Adhesive tape

Abstract

The present invention addresses the problem of providing an adhesive tape for wafer processing that combines tensile stress and uniform expandability suitable for a step of dividing an adhesive layer by expansion, and high shrinkability that can eliminate slack of the tape that occurs during expansion in a heat shrinking step. The solution to the problem is an adhesive tape for wafer processing comprising an adhesive layer and a base film of at least two layers having a first resin layer and a second resin layer that have an ionomer resin content of at least 80 mass%, the ionomer resin comprising a resin in which the Vicat softening temperature is 50 to 79°C and some of the acid groups of an ethylene-unsaturated carboxylic acid copolymer have been neutralized by zinc ions, the ratio of structural units derived from unsaturated carboxylic acids contained in the ethylene-unsaturated carboxylic acid copolymer being 6.9-18.0 mass% assuming 100 mass% to be all of the structural units of the ethylene-unsaturated carboxylic acid copolymer, and the zinc ion concentration being 0.38–0.60 mmol per gram of ethylene-unsaturated carboxylic acid copolymer.

Description

Technical Field

[0001] The present invention relates to an adhesive tape for wafer processing used in the manufacturing process of semiconductor devices, and more particularly to an expandable adhesive tape for wafer processing used to obtain a semiconductor chip with a die bond film (adhesive layer).

Background Art

[0002] In the manufacturing process of semiconductor devices such as ICs, in order to obtain a semiconductor chip with an adhesive film having a chip-equivalent size for die bonding, a dicing die bond film in which a dicing tape composed of a base material and an adhesive layer and a die bond film (hereinafter sometimes referred to as an "adhesive layer" or an "adhesive film") are integrated may be used.

[0003] The above dicing die bond film is provided with a die bond film (hereinafter sometimes referred to as an "adhesive film" or an "adhesive layer") on the adhesive layer of the dicing tape so as to be peelable. Specifically, in the manufacturing of semiconductor devices, for example, a semiconductor wafer is attached and placed on the die bond film of the dicing die bond film, and the semiconductor wafer is diced together with the die bond film to obtain individual semiconductor chips with adhesive films. Then, the semiconductor chip is peeled (picked up) from the adhesive layer of the dicing tape as a semiconductor chip with a die bond film together with the die bond film, and the semiconductor chip is fixed to an adherend such as a lead frame, a wiring board, or another semiconductor chip via the die bond film.

[0004] The above dicing die bond film is preferably used from the viewpoint of productivity improvement. However, as a method for obtaining a semiconductor chip with a die bond film using the dicing die bond film, in recent years, instead of the conventional full-cut method using a high-speed rotating dicing blade, when singulating a semiconductor wafer to be thinned into chips, it is said that chipping and pickup defects caused by cutting chips of the adhesive layer can be suppressed. Therefore, (1) a method by DBG (Dicing Before Grinding), (2) a method by stealth dicing (registered trademark), etc. have been proposed.

[0005] In the method by DBG of (1) above, first, without completely cutting the semiconductor wafer using a dicing blade, a dividing groove with a predetermined depth is formed on the surface of the semiconductor wafer, and then back grinding is performed to a predetermined thickness while appropriately adjusting the grinding amount, thereby obtaining a divided body of the semiconductor wafer including a plurality of semiconductor chips or a thinned semiconductor wafer that can be singulated into a plurality of semiconductor chips. Then, the divided body of the semiconductor wafer or the semiconductor wafer that can be singulated into the semiconductor chips is attached to a dicing die bond film, and the dicing tape is expanded at a low temperature (for example, -30°C or higher and 0°C or lower) (hereinafter, may be referred to as "cool expansion"). Along the above dividing groove, the die bond film embrittled at a low temperature is cut (hereinafter, may be referred to as "divided") into sizes corresponding to individual semiconductor chips, or cut together with the semiconductor wafer. The expansion of the dicing tape is performed by pushing up an expansion table provided under the dicing tape. Finally, by peeling off by pickup from the adhesive layer of the dicing tape, individual semiconductor chips with a die bond film can be obtained.

[0006] In the method of stealth dicing described in (2) above, first, a semiconductor wafer thinned to a predetermined thickness by back grinding is attached to a dicing die bond film, and a dicing planned line is formed while irradiating a laser beam into the semiconductor wafer to selectively form a modified region (modified layer). Then, by cooling and expanding the dicing tape, cracks are propagated vertically from the modified region to the semiconductor wafer, and the semiconductor wafer is individually cut along the above-mentioned dicing planned line together with the die bond film embrittled at a low temperature. Finally, it can be peeled off by picking up from the adhesive layer of the dicing tape to obtain individual semiconductor chips with die bond films. At this time, the dicing tape is required to have sufficient stress and uniform and isotropic extensibility to surely cut the semiconductor wafer with a die bond film, and various proposals have been made so far.

[0007] For example, Patent Document 1 aims to provide a wafer processing tape that does not soften excessively during the heat treatment when using a thermosetting type surface protection tape and has uniform and isotropic extensibility that can be used in the expanding process of dividing the adhesive layer. It discloses a base film composed of multiple layers of two or more layers, including a bottom layer made of a thermoplastic resin with a Vicat softening point of 80°C or higher defined by JIS K7206, and other layers other than the bottom layer made of a thermoplastic resin with a Vicat softening point of 50°C or higher and less than 80°C defined by JIS K7206.

[0008] Also, in the method by DBG described in (1) above, instead of forming a dividing (cutting) groove on the semiconductor wafer surface with a dicing blade, after selectively providing a modified region inside the semiconductor wafer by stealth dicing, the semiconductor wafer is thinned to a predetermined thickness by back grinding, and a divided body of the semiconductor wafer with a die bond film or a semiconductor wafer with a die bond film that can be fragmented can also be obtained. This is a method called SDBG (Stealth Dicing Before Griding).

[0009] Incidentally, in order to appropriately pick up the semiconductor chip with the die bond film described above, usually, as a previous step, a dicing tape is expanded near room temperature (hereinafter sometimes referred to as "room temperature expansion") for the purpose of widening the interval between adjacent semiconductor chips with die bond films cut in the above cool expansion step (hereinafter sometimes referred to as "kerf width"). In this step, when pushing up the expansion table provided under the dicing tape, the stress applied to the dicing tape at the peripheral edge of the expansion (expanded) table is greater than that at the center of the expansion table. Therefore, when the expansion table is lowered after room temperature expansion to release the expanded state, a slack corresponding to the peripheral edge of the expansion table occurs in the outer peripheral portion of the dicing tape. Such slack makes the interval between the divided semiconductor chips non-uniform or narrower, which causes product defects in the pickup process. Specifically, in the pickup process, it may not be possible to appropriately pick up the semiconductor chip with the die bond film from the adhesive layer of the dicing tape. For example, when picking up the semiconductor chip, damage caused by chip-to-chip contact between the chip and the adjacent chip and re-adhesion caused by contact between the adhesive layers may occur, resulting in a decrease in the pickup yield.

[0010] As a means for eliminating the slack of such a dicing tape, a heat shrinkage process (hereinafter sometimes referred to as a "heating and shrinking process") is known in which hot air is blown onto the slack portion of the outer peripheral portion of the dicing tape so that the surface temperature of the portion becomes about 80°C, and the slack portion is heated and shrunk to restore it to its original state. In order for this process to be appropriately carried out, the dicing tape needs to have high heat shrinkability at a temperature of about 80°C. By this appropriate heat shrinkage process, the region inside the outer peripheral portion of the dicing tape (the region where the semiconductor wafer is adhered) reaches a tension state in which a predetermined degree of tension acts. As a result, the interval (kerf width) between individual semiconductor chips can be fixed and held while being widened, so that the individual semiconductor chips with diced bond films can be appropriately picked up from the adhesive layer of the dicing tape.

[0011] For example, Patent Document 2 aims to provide an adhesive tape for fixing a semiconductor wafer that can cope with the expansion of the chip interval due to an increase in the elongation rate, the slack generated by expansion can be sufficiently removed by hot air blowing, and no storage error occurs during cassette storage after the pickup is completed. In an adhesive tape for fixing a semiconductor wafer having an adhesive layer on a base film, a semiconductor wafer fixing adhesive tape is disclosed in which the base film has at least one layer containing an ionomer resin having a melting point of 60 to 80°C.

[0012] Also, Patent Document 3 aims to provide a wafer processing tape having uniform expandability suitable for the process of dividing the adhesive layer by expansion, showing sufficient shrinkability in the heating and shrinking process, and not causing defects due to slack after the heating and shrinking process. A base film made of a thermoplastic crosslinked resin having a Vicat softening point defined by JIS K7206 of 50°C or higher and less than 90°C and an increase in stress due to heat shrinkage of 9 MPa or higher is disclosed.

Prior Art Documents

Patent Documents

[0013] [Patent Document 1] JP-A-2009-231700 [Patent Document 2] JP-A-9-7976 [Patent Document 3] JP-A-2011-216508 [Summary of the Invention] [Problems to be Solved by the Invention]

[0014] The tape for wafer processing in Patent Document 1 uses a base film having a lowermost layer made of a thermoplastic resin with a Vicat softening point of 80°C or higher. Therefore, it is said that sticking to the chuck table does not occur and the adhesive layer can be well separated. However, there is no description regarding the heat shrinkage process for removing the slack of the dicing tape after expansion and ensuring the kerf width between individual semiconductor chips, or the heat shrinkability of the tape for wafer processing. According to the study by the present inventors, when the Vicat softening point of the thermoplastic resin used for the base film is high, for example, when hot air is blown so that the surface temperature of the slack portion becomes about 80°C, the heat shrinkability may not be sufficiently high, and there is a possibility that the slack cannot be restored to its original state by the heat shrinkage process and the kerf width between individual semiconductor chips cannot be sufficiently ensured. Also, it is unclear whether an adhesive layer having a large thickness and high fluidity, such as the wire-embedded die bond film described later, can be cut.

[0015] In addition, the adhesive tape for fixing a semiconductor wafer in Patent Document 2 has at least one layer containing an ionomer resin with a melting point of 60 to 80°C in the base film. Therefore, it can cope with the expansion of the chip interval due to the increase in the elongation rate, the sag generated by expansion can be sufficiently removed by hot air blowing, and it is said that the occurrence of storage errors can be prevented when storing in a cassette after the pickup is completed. However, in the above heat shrinkage process, for example, when hot air is blown so that the surface temperature of the slack portion becomes about 80°C, if the melting point of the ionomer resin used for the base film is low, the resin will soften and fluidize excessively during heat shrinkage, so there is a risk that the adhesive tape for fixing a semiconductor wafer will be deformed or worst of all, melted. In addition, there is no description about the adhesive layer at all. When this adhesive tape for fixing a semiconductor wafer is applied to methods such as DBG or stealth dicing, it is unclear whether it has the stress capable of cutting the semiconductor wafer together with the die bond film (adhesive layer). Furthermore, it is also unclear whether a sufficient kerf width is ensured when the chip is subjected to the process of releasing the expanded state after heat shrinkage and picking up the chip.

[0016] In addition, the tape for wafer processing in Patent Document 3 uses a base film made of a thermoplastic crosslinked resin with a Vicat softening point of 50°C or higher and less than 90°C and a stress increase due to heat shrinkage of 9 MPa or higher. Therefore, there is very little slack after the heat shrinkage process, and the divided semiconductor chips and the individualized adhesives can be stably fixed on the tape for wafer processing, and it is said that good pick-up properties can be obtained. However, according to the study by the present inventors, depending on the performance of the thermoplastic crosslinked resin used for the base film, for example, when the surface temperature of the slack portion is about 80°C and hot air is blown, the heat shrinkability may not be sufficiently high, and there is a risk that the slack cannot be restored to the original state by the heat shrinkage process and a sufficient kerf width between individual semiconductor chips cannot be ensured. In addition, it is unclear whether an adhesive layer with a large thickness and high fluidity like the wire-embedded die bond film described later can be cut.

[0017] As described above, in the prior art, although a certain effect can be obtained in eliminating the slack of the tape after expansion, depending on the performance of the base film containing the thermoplastic cross-linked resin used, the shrinkage due to heating is not sufficient, slack remains after the heat shrinkage process, and the separated semiconductor chips and the fragmented adhesive layers cannot be stably fixed on the tape with the kerf width widened, and adjacent semiconductor chips may come into contact and be damaged, or the adhesive layers may come into contact and re-adhere, resulting in a deterioration in the yield of the semiconductor component manufacturing process, and there was still room for improvement.

[0018] In addition, in recent years, with the thinning of semiconductor wafers, chip cracking has become more likely to occur during wire bonding in the multi-layer stacking process of semiconductor chips. As a countermeasure for this problem, a wire-embedded die bond film having a spacer function has been proposed. This wire-embedded die bond film needs to embed the wire without gaps during die bonding, and compared with the conventional general-purpose die bond film described above, it tends to be thicker and have higher fluidity (lower melt viscosity at high temperatures). Therefore, such a wire-embedded die bond film is less likely to be cut during cool expansion compared to a general-purpose die bond film used in a form where the conventional wire is not embedded in the adhesive layer, and re-adhesion between the cut die bond films with a thick thickness and collision between semiconductor chips are likely to occur, and the pick-up property tends to be poor. To address this, if the expansion amount of the adhesive tape for wafer processing is increased, the slack amount also increases, and it may be difficult to eliminate the slack by the heat shrinkage process. Therefore, from this perspective as well, there has been a strong demand for an adhesive tape for wafer processing that can be cut well even for a die bond film that is difficult to cut, such as a wire-embedded die bond film, and can stably fix the separated semiconductor chips and the fragmented adhesive layers on the tape with the kerf width sufficiently widened.

[0019] The present invention has been made in view of the problems of such prior art, and has a tensile stress suitable for the step of dividing an adhesive layer, particularly a difficult-to-cut adhesive layer typified by a wire-embedded die bond film, by expansion, and a uniform expandability, and a high shrinkage property capable of eliminating the tape slack generated during expansion in the heat shrinkage step. An object of the present invention is to provide an adhesive tape for wafer processing having both of these properties.

Means for Solving the Problems

[0020] That is, the present invention provides the following embodiments. [1] An expandable adhesive tape for wafer processing used when dividing an adhesive layer along a chip by expansion, comprising a base film and an adhesive layer provided on the base film, The base film has at least a first resin layer containing an ionomer resin at a content ratio of 80% by mass or more, and a second resin layer containing an ionomer resin of the same or different type as the ionomer resin at a content ratio of 80% by mass or more, and has a laminated structure of two or more layers, Each of the ionomer resins contains a zinc ion and an ethylene-unsaturated carboxylic acid copolymer which is a base polymer of the resin, and has a Vicat softening temperature defined in JIS K7206 within a range having a lower limit value of 50°C and an upper limit value of 79°C, The ethylene-unsaturated carboxylic acid copolymer has a content ratio of a structural unit derived from an unsaturated carboxylic acid within a range having a lower limit value of 6.9% by mass and an upper limit value of 18.0% by mass based on 100% by mass of the total amount of the structural units constituting the ethylene-unsaturated carboxylic acid copolymer, The concentration of the zinc ion has a value within a range having a lower limit value of 0.38 mmol per 1 g of the ethylene-unsaturated carboxylic acid copolymer and an upper limit value of 0.60 mmol. An adhesive tape for wafer processing.

[0021] [2] When the content ratio of the structural unit derived from the unsaturated carboxylic acid is based on 100% by mass of the total amount of the structural units constituting the ethylene-unsaturated carboxylic acid copolymer, the ethylene-unsaturated carboxylic acid copolymer is in the range of 8.0% by mass or more and 15.0% by mass or less, and the wafer processing adhesive tape has the form [1].

[0022] [3] The concentration of the zinc ions is in the range of 0.41 mmol or more and 0.55 mmol or less per 1 g of the ethylene-unsaturated carboxylic acid copolymer, and the wafer processing adhesive tape has the form [1] or [2].

[0023] [4] The total thickness of the base film is in the range of 60 μm or more and 150 μm or less. The thickness of each resin layer containing the ionomer resin in the base film at a content ratio of 80% by mass or more is in the range of 10 μm or more and 50 μm or less. The total thickness of all the resin layers containing the ionomer resin at a content ratio of 80% by mass or more is 65% or more of the total thickness of the base film, and the wafer processing adhesive tape has any of the forms [1] to [3].

[0024] [5] The ethylene-unsaturated carboxylic acid copolymer is composed of at least one copolymer selected from the group consisting of a binary copolymer of ethylene-(meth)acrylic acid and a ternary copolymer of ethylene-(meth)acrylic acid-(meth)acrylic acid alkyl ester, and the wafer processing adhesive tape has any of the forms [1] to [4].

[0025] 6 A method for manufacturing a semiconductor chip or a semiconductor device using any of the wafer processing adhesive tapes having the forms [1] to 5 .

Advantages of the Invention

[0026] ​According to the present invention, it is possible to provide an adhesive tape for wafer processing that has a tensile stress and uniform extensibility suitable for the step of dividing an adhesive layer by expansion, and a high shrinkability capable of eliminating tape slack generated during expansion in the heat shrinkage step. That is, the adhesive layer can be divided well, the tape slack generated during expansion can be removed by the heat shrinkage step, and the divided semiconductor chips and the fragmented adhesive layers can be stably fixed on the adhesive tape for wafer processing while maintaining a sufficient kerf width. As a result, the occurrence of damage due to contact between adjacent semiconductor chips and re-adhesion due to contact between adhesive layers, as described above, is suppressed, and the pick-up property becomes better. And, even when a wire embedding type die bond film having a large thickness and high fluidity is used as the adhesive layer, the same effect can be obtained. Further, it is possible to provide a method for manufacturing a semiconductor chip or a semiconductor device using the adhesive tape for wafer processing.

Brief Description of Drawings

[0027]

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[0028] Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawings as necessary. However, the present invention is not limited to the following embodiments. (Configuration of Adhesive Tape for Wafer Processing)

[0029] (a) and (b) of Fig. 1 are cross-sectional views showing an example of the two-layer structure of the base film 1 of the adhesive tape for wafer processing to which the present embodiment is applied. The two-layer base film 1 of the adhesive tape for wafer processing according to the present embodiment may have the same ionomer resin (see 1-A in Fig. 1(a), one type two-layer type) contained in the first resin layer and the second resin layer at a content ratio of 80% by mass or more, or the ionomer resins contained in the first resin layer and the second resin layer at a content ratio of 80% by mass or more may be different types of ionomer resins (see 1-B in Fig. 1(b), two types two-layer type).

[0030] (c) to (e) of Fig. 2 are cross-sectional views showing an example of the three-layer structure of the base film 1 of the adhesive tape for wafer processing to which the present embodiment is applied. The three-layer base film 1 of the adhesive tape for wafer processing according to the present embodiment may have all the ionomer resins contained in the first resin layer, the second resin layer, and the third resin layer at a content ratio of 80% by mass or more being the same ionomer resin (see 1-C in Fig. 2(c), one type three-layer type), or the ionomer resins contained in the first resin layer and the second resin layer at a content ratio of 80% by mass or more may be the same ionomer resin, and the ionomer resin contained in the third resin layer at a content ratio of 80% by mass or more may be a different type of ionomer resin (see 1-D in Fig. 2(d), two types three-layer type), or the ionomer resins contained in the first resin layer, the second resin layer, and the third resin layer at a content ratio of 80% by mass or more may all be different types of ionomer resins (see 1-E in Fig. 2(e), three types three-layer type). In addition, in the entire base film, the layer positions of the first resin layer, the second resin layer, and the third resin layer are not particularly limited.

[0031] (f) and (g) of FIG. 3 are cross-sectional views showing an example of a laminated structure of another aspect of the base film 1 of the adhesive tape for wafer processing to which the present embodiment is applied. The three-layer base film 1 of the adhesive tape for wafer processing according to the present embodiment is composed of a resin in which the first resin layer and the second resin layer contain the same ionomer resin at a content ratio of 80% by mass or more, and the third resin layer is composed of another resin other than the resin containing the ionomer resin constituting the first resin layer and the second resin layer at a content ratio of 80% by mass or more (see 1-F in FIG. 3, two types and three-layer type), or the first resin layer and the second resin layer are each composed of a resin containing a different type of ionomer resin at a content ratio of 80% by mass or more, and the third resin layer is composed of another resin other than the resin containing the ionomer resin constituting the first resin layer and the second resin layer at a content ratio of 80% by mass or more (see 1-G in FIG. 3, three types and three-layer type). In the entire base film, the layer positions of the first resin layer, the second resin layer, and the third resin layer are not particularly limited.

[0032] The base film 1 of the adhesive tape for wafer processing to which the present embodiment is applied has at least a first resin layer containing an ionomer resin at a content ratio of 80% by mass or more, and a second resin layer containing the same or a different type of ionomer resin at a content ratio of 80% by mass or more, and is composed of a laminated structure of two or more layers. The number of layers has two layers of the above-mentioned first resin layer and second resin layer, and is not particularly limited as long as the effects of the present invention are not impaired. From the viewpoints of the mechanical properties and productivity of the base film 1, etc., the number of layers is preferably in the range of two or more and five or less. In the entire base film, the layer positions of the first resin layer and the second resin layer are not particularly limited.

[0033] FIG. 4 is a cross-sectional view showing an example of the configuration of an adhesive tape for wafer processing to which the present embodiment is applied. As shown in FIG. 4, the adhesive tape 10 for wafer processing has a configuration in which an adhesive layer 2 is provided on a base film 1. A typical example of such a laminated structure is a dicing tape. Although not shown, a base sheet (release liner) having releasability may be provided on the surface of the adhesive layer 2 of the adhesive tape 10 for wafer processing (the surface opposite to the surface facing the base film 1). The base film 1 includes at least a first resin layer containing an ionomer resin at a content ratio of 80% by mass or more, and a second resin layer containing an ionomer resin of the same or different type as the ionomer resin at a content ratio of 80% by mass or more, and is composed of a laminated structure of two or more layers. As the adhesive for forming the adhesive layer 2, for example, an active energy ray curable acrylic adhesive that cures and shrinks by irradiating active energy rays such as ultraviolet rays (UV) and thus reduces the adhesive force to the adherend is used.

[0034] FIG. 5 is a cross-sectional view showing an example of a configuration in which an adhesive layer 3 is detachably provided on the adhesive tape 10 for wafer processing to which the present embodiment is applied. The adhesive layer 3 is detachably adhered and laminated on the adhesive layer 2 of the adhesive tape 10 for wafer processing. A typical example of such a laminated structure is a dicing die bond film 20.

[0035] The dicing die bond film 20 with such a configuration is used, for example, as follows in the semiconductor manufacturing process. On the die bond film (adhesive layer) 3 of the dicing die bond film 20, a thin-film semiconductor wafer with split grooves formed on the surface by a blade or a thin-film semiconductor wafer with a modified layer formed inside by a laser is pasted and held (adhered), and the semiconductor wafer is cut together with the die bond film 3 by cool expansion to obtain individual semiconductor chips with the die bond film 3. Alternatively, on the die bond film 3 of the dicing die bond film 20, a thin-film semiconductor wafer is pasted and held (adhered), and after forming a modified layer inside the semiconductor wafer by a laser in that state, the semiconductor wafer is cut together with the die bond film 3 by cool expansion to obtain individual semiconductor chips with the die bond film 3. Alternatively, on the die bond film 3 of the dicing die bond film 20, a split body of a semiconductor wafer including a plurality of semiconductor chips is pasted and held by transfer from a back grind tape, and then the die bond film 3 is cut along the semiconductor chips by cool expansion to obtain individual semiconductor chips with the die bond film 3.

[0036] Next, after sufficiently expanding the kerf width between the semiconductor chips with the die bond film 3 by normal temperature expansion, the individual semiconductor chips with the die bond film 3 are peeled off from the adhesive layer 2 of the wafer processing adhesive tape (dicing tape) 10 by a pick-up process. The obtained semiconductor chips with the die bond film (adhesive film) 3 are fixed to an adherend such as a lead frame, a wiring board, or another semiconductor chip through the die bond film (adhesive film) 3. Although not shown, a base sheet (release liner) having releasability may be provided on the surface of the adhesive layer 2 of the wafer processing adhesive tape (dicing tape) 10 (the surface opposite to the surface facing the base film 1) and the surface of the die bond film 3 (the surface opposite to the surface facing the adhesive layer 2), respectively.

[0037] (Wafer processing adhesive tape) <<Base film>> The base film 1 of the adhesive tape 10 for wafer processing according to the present invention comprises at least a first resin layer containing a specific ionomer resin (details will be described later) at a content ratio of 80% by mass or more, and a second resin layer containing a specific ionomer resin of the same or different type as the above ionomer resin at a content ratio of 80% by mass or more, and has a laminated structure of two or more layers. When the base film 1 has only one resin layer containing an ionomer resin, that is, when the base film 1 is composed of a single layer of a resin layer containing an ionomer resin, especially when increasing the thickness of the base film 1, it is necessary to increase the extrusion flow rate of the resin. Therefore, the resin pressure and motor load in the extruder may become excessively large during film formation, the film formation accuracy of the base film 1 may deteriorate, and it may be difficult to stably form a long film. As a result, unnecessary wrinkles may occur when the base film 1 is wound up, causing problems such as poor appearance and a decrease in pick-up yield. On the other hand, when the base film is composed of a laminate of two or more layers including at least a first resin layer and a second resin layer containing an ionomer resin, compared with the case of forming a base film 1 of the same thickness with a single-layer structure, the extrusion flow rate can be controlled without excessively increasing the resin pressure and motor load in the extruder. Therefore, it is suitable from the viewpoints of film formation accuracy and stable film formation, and unnecessary wrinkles do not occur in the base film 1. Also, it is suitable in that the film formation speed of the base film 1 can be increased and in that it is easy to control the balance of physical properties such as tensile stress, uniform extensibility during expansion, and shrinkage during the heat shrinkage process.

[0038] Here, "containing ~ at a content ratio of 80 mass% or more" means that when the total mass of the resin in each of the first resin layer and the second resin layer is taken as 100 mass% as a reference, the content ratio of the specific ionomer resin is 80 mass% or more. The content ratio of the specific ionomer resin is preferably in the range of 85 mass% or more and 100 mass% or less, and more preferably in the range of 90 mass% or more and 100 mass% or less. That is, the first resin layer and the second resin layer of the base film 1 may be composed only of the specific ionomer resin. When the content ratio of the specific ionomer resin is less than 80 mass%, the mechanical properties exhibited by the appropriate and advanced cross-linked structure of the ionomer resin, that is, the tensile stress and uniform extensibility during the expansion of the adhesive tape 10 for wafer processing, and the shrinkage property in the heat shrinkage process become insufficient. As a result, there is a risk that the die bond film (adhesive layer) 3 cannot be cut well, or that the kerf width between individual semiconductor chips cannot be ensured sufficiently, and good pick-up property may not be obtained.

[0039] The number of resin layers of the base material film 1 composed of the above-described laminated structure of two or more layers is not particularly limited, but from the viewpoints of the characteristics and productivity of the base material film 1, etc., it is preferably in the range of two or more and five or less layers, and preferably in the range of two or more and three or less layers. Although details will be described later, in the above base material film 1, the total thickness of all resin layers containing the specific ionomer resin at a content ratio of 80% by mass or more is preferably 65% or more of the total thickness of the base material film 1. More preferably, it is in the range of 80% or more and 100% or less, and still more preferably in the range of 90% or more and 100% or less. For example, when the above base material film 1 has a three-layer laminated structure having a third resin layer in addition to the first resin layer and the second resin layer, first, the third resin layer may be composed of a resin containing the specific ionomer resin at a content ratio of 80% by mass or more, similar to the first resin layer and the second resin layer as shown in FIG. 2, or may be composed only of the specific ionomer resin. Further, the third resin layer may be composed of other resins other than the resin containing the specific ionomer resin constituting the first resin layer and the second resin layer at a content ratio of 80% by mass or more, as shown in FIG. 3. Here, in the case of the base material film 1 having the former configuration (the mode shown in FIG. 2), the total thickness of all resin layers containing the specific ionomer resin at a content ratio of 80% by mass or more corresponds to 100% of the total thickness of the base material film 1, which is particularly preferable as the present embodiment.

[0040] On the other hand, in the case of the base film 1 having the latter configuration (the embodiment shown in FIG. 3), the total thickness of each of the first resin layer and the second resin layer containing the above-specified ionomer resin at a content ratio of 80% by mass or more is preferably 65% or more of the total thickness of the base film 1, more preferably in the range of 80% or more and 99% or less, and still more preferably in the range of 90% or more and 99% or less. When the total thickness of each of the resin layers containing the above-specified ionomer resin at a content ratio of 80% by mass or more is less than 65% of the total thickness of the base film 1, the mechanical properties exhibited by the appropriate and highly crosslinked structure of the ionomer resin, that is, the tensile stress and uniform extensibility during the expansion of the adhesive tape 10 for wafer processing, and the shrinkage property during the heat shrinkage process become insufficient. As a result, there is a risk that the die bond film (adhesive layer) 3 may not be cut well, or that the kerf width between individual semiconductor chips cannot be ensured sufficiently, and good pick-up property may not be obtained.

[0041] <Ionomer resin> The specific ionomer resin contained in the first resin layer and the second resin layer of the base film 1 of the present embodiment at a content ratio of 80% by mass or more will be described.

[0042] All of the above-specified ionomer resins contain an ethylene-unsaturated carboxylic acid copolymer, which is the base polymer of the resin, and zinc ions, and have a Vicat softening temperature defined by JIS K7206 within a range having a lower limit value of 50 °C and an upper limit value of 79 °C. In the above ethylene-unsaturated carboxylic acid copolymer, the content ratio of the structural unit derived from the unsaturated carboxylic acid has a value within a range having a lower limit value of 6.9% by mass and an upper limit value of 18.0% by mass based on 100% by mass of the total amount of the structural units constituting the ethylene-unsaturated carboxylic acid copolymer. Further, the concentration of the above zinc ions has a value within a range having a lower limit value of 0.38 mmol per 1 g of the ethylene-unsaturated carboxylic acid copolymer and an upper limit value of 0.60 mmol.

[0043] In the ionomer resin used for the base film 1, by setting the content ratio of the structural unit derived from the unsaturated carboxylic acid and the concentration of zinc ions contained in the ethylene-unsaturated carboxylic acid copolymer within the above ranges, although details will be described later, the acid groups of the ethylene-unsaturated carboxylic acid copolymer are appropriately neutralized by zinc ions, and in the continuous layer of the ethylene-unsaturated carboxylic acid copolymer, the development of ion aggregates (clusters) formed by the aggregate of carboxylate ions of acid groups derived from unsaturated carboxylic acids and zinc ions is sufficient and appropriate, and the cross-linking form is optimized. Therefore, it is possible to realize an adhesive tape for wafer processing that has a tensile stress and uniform extensibility suitable for the cool expand process, and a high shrinkability capable of eliminating the tape slack generated during expansion in the heat shrink process.

[0044] The above ethylene-unsaturated carboxylic acid copolymer is at least a binary copolymer in which ethylene and an unsaturated carboxylic acid are copolymerized, and may further be a ternary or higher multi-component copolymer in which other copolymerization components such as a third and a fourth are copolymerized. In addition, the ethylene-unsaturated carboxylic acid copolymer may be used alone or in combination of two or more ethylene-unsaturated carboxylic acid copolymers.

[0045] Examples of the unsaturated carboxylic acid constituting the above ethylene-unsaturated carboxylic acid binary copolymer include unsaturated carboxylic acids having 4 to 8 carbon atoms such as acrylic acid, methacrylic acid, ethacrylic acid, itaconic acid, itaconic anhydride, fumaric acid, crotonic acid, maleic acid, and maleic anhydride. Among these, as the unsaturated carboxylic acid, acrylic acid or methacrylic acid is preferable.

[0046] When the above ethylene-unsaturated carboxylic acid copolymer is a terpolymer or higher multi-component copolymer, in addition to ethylene and unsaturated carboxylic acid that constitute the above binary copolymer, other copolymer components such as third, fourth, and other copolymer components that form the multi-component copolymer may be included. Examples of other copolymer components such as third and fourth include unsaturated carboxylic acid esters, unsaturated hydrocarbons, vinyl esters, oxides such as vinyl sulfate and vinyl nitrate, halogen compounds, vinyl group-containing primary and secondary amine compounds, carbon monoxide, sulfur dioxide, and the like. Among these, unsaturated carboxylic acids and unsaturated hydrocarbons are preferred as other copolymer components.

[0047] As the above unsaturated carboxylic acid ester, an alkyl ester of an unsaturated carboxylic acid is preferred. The number of carbon atoms in the alkyl moiety of the alkyl ester is preferably in the range of 1 or more and 12 or less, more preferably in the range of 1 or more and 8 or less, and still more preferably in the range of 1 or more and 4 or less. Examples of the alkyl moiety include methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, secondary butyl, 2-ethylhexyl, isooctyl, and the like.

[0048] Specific examples of the above unsaturated carboxylic acid alkyl ester include unsaturated carboxylic acid alkyl esters in which the number of carbon atoms in the alkyl moiety is in the range of 1 or more and 12 or less (for example, alkyl esters of acrylic acid such as methyl acrylate, ethyl acrylate, isobutyl acrylate, n-butyl acrylate, isooctyl acrylate, etc., alkyl esters of methacrylic acid such as methyl methacrylate, ethyl methacrylate, isobutyl methacrylate, etc., alkyl esters of maleic acid such as dimethyl maleate, diethyl maleate, etc.). Among these, (meth)acrylic acid alkyl esters in which the number of carbon atoms in the alkyl moiety is in the range of 1 or more and 4 or less are more preferred. From the viewpoint of controlling the Vicat softening temperature and suppressing the necking phenomenon during the expansion of the adhesive tape 10 for wafer processing, isobutyl methacrylate in which the number of carbon atoms in the alkyl moiety is 4 is particularly preferred.

[0049] Examples of the unsaturated hydrocarbon include propylene, butene, 1,3-butadiene, pentene, 1,3-pentadiene, 1-hexene, and the like.

[0050] Examples of the vinyl ester include vinyl acetate, vinyl propionate, and the like, and examples of the halogen compound include vinyl chloride, vinyl fluoride, and the like.

[0051] The form of the ethylene-unsaturated carboxylic acid copolymer may be any of a block copolymer, a random copolymer, and a graft copolymer, and may be any of a binary copolymer and a multicomponent copolymer of three or more components. Among them, from the viewpoint of industrial availability, a binary random copolymer, a ternary random copolymer, a graft copolymer of a binary random copolymer, or a graft copolymer of a ternary random copolymer is preferable, a binary random copolymer or a ternary random copolymer is more preferable, and a ternary random copolymer is further preferable from the viewpoint of uniform expandability during expansion of the adhesive tape 10 for wafer processing.

[0052] Preferable specific examples of the ethylene-unsaturated carboxylic acid copolymer include binary copolymers of ethylene-(meth)acrylic acid such as ethylene-acrylic acid copolymer and ethylene-methacrylic acid copolymer, and ternary copolymers of ethylene-(meth)acrylic acid-(meth)acrylic acid alkyl ester such as ethylene-methacrylic acid-isobutyl acrylate copolymer. From the viewpoint of uniform expandability during expansion of the adhesive tape 10 for wafer processing, a ternary copolymer of ethylene-(meth)acrylic acid-(meth)acrylic acid alkyl ester such as ethylene-methacrylic acid-isobutyl acrylate copolymer is preferable. Further, a commercially available product marketed as an ethylene-unsaturated carboxylic acid copolymer may be used. For example, Nuclel (registered trademark) series manufactured by Mitsui DuPont Polychemical Co., Ltd. can be used.

[0053] The above ethylene-unsaturated carboxylic acid copolymer has a content ratio of the structural unit derived from the unsaturated carboxylic acid within a range where the lower limit is 6.9% by mass and the upper limit is 18.0% by mass, based on 100% by mass of the total amount of the structural units constituting the ethylene-unsaturated carboxylic acid copolymer. The lower limit of the content ratio of the structural unit derived from the unsaturated carboxylic acid is preferably 8.0% by mass, more preferably 10.0% by mass. On the other hand, the upper limit is preferably 15.0% by mass, more preferably 12.0% by mass. In the above specific ionomer resin using the ethylene-unsaturated carboxylic acid copolymer as a base polymer, the acid groups (carboxyl groups) of the ethylene-unsaturated carboxylic acid copolymer are neutralized by zinc ions at an arbitrary ratio, that is, a structure in which intermolecular pseudo-crosslinking is formed. However, when the content ratio of the structural unit derived from the unsaturated carboxylic acid is less than 6.9% by mass, the crosslinking effect by zinc ions is small, and in the continuous layer of the ethylene-unsaturated carboxylic acid copolymer, the development of ion aggregates (clusters) formed by the aggregate of carboxylate ions of the acid groups derived from the unsaturated carboxylic acid and zinc ions is also insufficient. Therefore, there is a possibility that the tensile stress and uniform extensibility during the expansion of the wafer processing adhesive tape 10, as well as the shrinkage property during the heat shrinkage process, may be insufficient.

[0054] As a result, there is a possibility that the die bond film (adhesive layer) 3 may not be cut well, and it may not be possible to sufficiently secure the kerf width between individual semiconductor chips, resulting in a lack of good pick-up property. Also, the Vicat softening temperature may become too high. On the other hand, when the content ratio of the structural unit derived from the unsaturated carboxylic acid exceeds 18.0% by mass, there is a possibility that the mechanical properties of the base film 1 may become insufficient. Also, depending on the content ratio of the unsaturated carboxylic acid ester, the Vicat softening temperature described later may become too low. When the content ratio of the structural unit derived from the unsaturated carboxylic acid is within the above range, it becomes easier to balance the appropriate tensile stress and uniform extensibility during the expansion of the wafer processing adhesive tape 10, as well as the shrinkage property during the heat shrinkage process.

[0055] Further, when the total amount of the constituent units constituting the ethylene-unsaturated carboxylic acid copolymer is taken as 100% by mass as a reference, the content ratio of the constituent unit derived from the unsaturated carboxylic acid ester preferably has a value within the range where the lower limit is 0% by mass and the upper limit is 16.0% by mass. From the viewpoint of uniform expandability including suppression of the necking phenomenon during expansion of the wafer processing adhesive tape 10, the lower limit of the content ratio of the constituent unit derived from the unsaturated carboxylic acid ester is more preferably 1.5% by mass, and even more preferably 5.0% by mass. On the other hand, the upper limit is more preferably 15.0% by mass, and even more preferably 12.0% by mass. When the content ratio of the constituent unit derived from the unsaturated carboxylic acid ester exceeds 16.0% by mass, there is a risk that the Vicat softening temperature described later may become too low depending on the content ratio of the unsaturated carboxylic acid. Also, there is a risk of blocking or fusion occurring in the base film 1.

[0056] When the ethylene-unsaturated carboxylic acid copolymer in the present invention is a binary copolymer of ethylene-unsaturated carboxylic acid, the preferred copolymerization ratio is such that when the total amount of the constituent units constituting the ethylene-unsaturated carboxylic acid copolymer is taken as 100% by mass as a reference, the content ratio of the constituent unit derived from ethylene is in the range of 82.0% by mass or more and 93.1% by mass or less, and the content ratio of the constituent unit derived from the unsaturated carboxylic acid is in the range of 6.9% by mass or more and 18.0% by mass or less. More preferably, the content ratio of the constituent unit derived from ethylene is in the range of 85.0% by mass or more and 92.0% by mass or less, and the content ratio of the constituent unit derived from the unsaturated carboxylic acid is in the range of 8.0% by mass or more and 15.0% by mass or less.

[0057] In addition, when the ethylene-unsaturated carboxylic acid copolymer is a terpolymer of ethylene-unsaturated carboxylic acid-unsaturated carboxylic acid ester, the preferred copolymerization ratio is as follows: when the total amount of the constituent units constituting the ethylene-unsaturated carboxylic acid copolymer is taken as 100% by mass as a reference, the content ratio of the constituent units derived from ethylene is in the range of 66.0% by mass or more and 91.6% by mass or less, the content ratio of the constituent units derived from unsaturated carboxylic acid is in the range of 6.9% by mass or more and 18.0% by mass or less, the content ratio of the constituent units derived from unsaturated carboxylic acid ester is in the range of 1.5% by mass or more and 16.0% by mass or less, and the total amount is adjusted to be 100% by mass. More preferably, the content ratio of the constituent units derived from ethylene is in the range of 70.0% by mass or more and 87.0% by mass or less, the content ratio of the constituent units derived from unsaturated carboxylic acid is in the range of 8.0% by mass or more and 15.0% by mass or less, and the content ratio of the constituent units derived from unsaturated carboxylic acid ester is in the range of 5.0% by mass or more and 15.0% by mass or less.

[0058] Generally, in an ionomer resin, the acid groups (carboxyl groups) of the ethylene-unsaturated carboxylic acid copolymer, which is the base polymer of the resin, are neutralized by metal ions such as lithium ions, sodium ions, potassium ions, rubidium ions, cesium ions, zinc ions, magnesium ions, and manganese ions at an arbitrary ratio. However, for the specific ionomer resin applied to the base film 1 of the present embodiment, from the viewpoint of stabilizing the crosslinked structure (strong crosslinked bond), it contains a zinc ion and the ethylene-unsaturated carboxylic acid copolymer, which is the base polymer of the resin. An ionomer resin in which at least a part of the acid groups of the ethylene-unsaturated carboxylic acid copolymer, which is the base polymer of the resin, is neutralized by zinc ions, which are divalent metal ions, is used.

[0059] Examples of the above zinc ion source include zinc oxides, hydroxides, carbonates, bicarbonates, acetates, formates, organic acid salts, etc. Specifically, for example, zinc oxide, zinc hydroxide, zinc acetate, zinc stearate, basic zinc carbonate, etc. may be mentioned. Among these, zinc oxide and zinc stearate are preferred. These zinc ion sources may be used alone or in combination of two or more.

[0060] The above specific ionomer resin is obtained by adding a zinc ion source to an ethylene-unsaturated carboxylic acid copolymer adjusted so that the content ratio of the structural unit derived from the unsaturated carboxylic acid, which is the base polymer of the resin, is within the range with 6.9% by mass as the lower limit and 18.0% by mass as the upper limit, and neutralizing (crosslinking) the acid groups (carboxyl groups) possessed by the copolymer with zinc ions at an arbitrary ratio. Here, in order to achieve both uniform expandability during expansion of the wafer processing adhesive tape 10 and shrinkability during the heat shrinkage process, not any ionomer resin will do. The concentration of the above zinc ions with respect to the ethylene-unsaturated carboxylic acid copolymer with the content ratio of the structural unit derived from the above unsaturated carboxylic acid specified is extremely important. That is, in the above specific ionomer resin applied to the base film 1 of the present embodiment, the concentration of the above zinc ions is adjusted to be within the range with 0.38 mmol per 1 g of the ethylene-unsaturated carboxylic acid copolymer as the lower limit and 0.60 mmol as the upper limit. The lower limit of the concentration of the above zinc ions is preferably 0.41 mmol, more preferably 0.46 mmol. On the other hand, the upper limit is preferably 0.55 mmol, more preferably 0.52 mmol.

[0061] When the concentration of the above zinc ions is less than 0.38 mmol, the cross-linking effect of the zinc ions on the ethylene-unsaturated carboxylic acid copolymer is small. In the continuous layer of the ethylene-unsaturated carboxylic acid copolymer, the development of ion aggregates (clusters) formed by the aggregation of carboxylate ions of acid groups derived from unsaturated carboxylic acids and zinc ions is also insufficient. Therefore, when the adhesive tape 10 for wafer processing is expanded, the uniform expandability and the shrinkability in the heat shrinkage process are insufficient. As a result, it may not be possible to sufficiently secure the kerf width between individual semiconductor chips, and good pick-up properties may not be obtained. On the other hand, when the concentration of the above zinc ions exceeds 0.60 mmol, depending on the content ratio of unsaturated carboxylic acid in the ethylene-unsaturated carboxylic acid copolymer which is the base polymer of a specific ionomer resin, the melt viscosity of the resin becomes too high, the resin pressure in the extruder increases, and the motor load becomes large, which may make it difficult to stably form a film.

[0062] When the concentration of the above zinc ions is within the above range, in the continuous layer of the ethylene-unsaturated carboxylic acid copolymer, the development of ion aggregates (clusters) formed by the aggregation of carboxylate ions of acid groups derived from unsaturated carboxylic acids and zinc ions is sufficient and appropriate. Therefore, due to its cross-linking effect, even when the base film 1 is expanded, the ion aggregates (clusters) are less likely to be broken, and as the expansion progresses, the number of molecular chain tensions between the ion aggregates increases and an appropriate tensile stress is expressed. On the other hand, in the heat shrinkage process after expansion, the entropy elasticity acts strongly, and the stretched and oriented molecules are likely to return to their original state. That is, the tensile stress during the stretching of the base film 1 and the restoring force during heating with respect to the strain after stretching become sufficient, and it is possible to achieve both the appropriate tensile stress and uniform expandability when the adhesive tape 10 for wafer processing is expanded, and the shrinkability in the heat shrinkage process. As a result, the cutting of the adhesive layer 3 is performed well, and furthermore, the kerf width between individual semiconductor chips can be sufficiently secured, and good pick-up properties can be obtained.

[0063] Furthermore, the above-specified ionomer resin has a Vicat softening temperature defined by JIS K7206 within a range where the lower limit is 50°C and the upper limit is 79°C. The lower limit of the Vicat softening temperature is preferably 54°C, more preferably 57°C. On the other hand, the upper limit is preferably 74°C, more preferably 64°C. If the Vicat softening temperature of the above-specified ionomer resin is less than 50°C, there is a risk of blocking during film formation or adhesive tape production. Also, in the heat shrinkage process, for example, when hot air is blown so that the surface temperature of the slack part becomes about 80°C, the resin may soften and fluidize excessively during heat shrinkage, resulting in the wafer processing adhesive tape 10 being deformed or melted more than necessary. On the other hand, if the Vicat softening temperature of the above-specified ionomer resin is 80°C or higher, for example, the heat shrinkability becomes insufficient when hot air is blown so that the surface temperature of the slack part becomes about 80°C. As a result, it may not be possible to ensure a sufficient kerf width between individual semiconductor chips, and good pick-up performance may not be obtained. When the Vicat softening temperature of the above-specified ionomer resin is within the above range, combined with the appropriate cross-linking effect of the above zinc ions, in the wafer processing adhesive tape 10, it is possible to achieve both a tensile stress and uniform extensibility suitable for the process of dividing the adhesive layer by expansion (expansion process), and a high shrinkability (recovery property) suitable for the process of eliminating and removing the tape slack generated during expansion (heat shrinkage process).

[0064] As described above, the specific ionomer resin contained in the first resin layer and the second resin layer of the base film 1 at a content ratio of 80% by mass or more has been explained. However, when the base film 1 has a laminated structure of three or more layers having other resin layers with the same configuration as the first resin layer and the second resin layer in addition to the first resin layer and the second resin layer (for example, the embodiment shown in FIG. 2), naturally, the above-specified ionomer resin can be used as the ionomer resin contained in the other resin layer at a content ratio of 80% by mass or more.

[0065] <Other Resin> The first resin layer and the second resin layer of the base material film 1 can contain other resins other than the specific ionomer resin in a content ratio of 20% by mass or less, provided that the effects of the present invention are not impaired. That is, when the total mass of the resins in the first resin layer and the second resin layer is set to 100% by mass as a reference respectively. Further, when the resin layers such as the third and fourth resin layers laminated on the first resin layer and the second resin layer contain the specific ionomer resin at a content ratio of 80% by mass or more, similarly, other resins other than the specific ionomer resin can be contained in a content ratio of 20% by mass or less. Furthermore, when another resin layer is laminated on the first resin layer and the second resin layer, the other resin layer can also be composed of other resins other than the resin containing the specific ionomer resin constituting the first resin layer and the second resin layer at a content ratio of 80% by mass or more.

[0066] The other resins are not particularly limited, but thermoplastic resins are preferred. Examples of the thermoplastic resins include ionomer resins other than the specific ionomer resin, thermoplastic olefin copolymers, thermoplastic polyurethanes, thermoplastic polyamides, thermoplastic styrene resins, thermoplastic polyesters, thermoplastic acrylic resins, thermoplastic polyolefins, thermoplastic polybutadienes, thermoplastic polyethers, thermoplastic polyether-polyolefin copolymers, thermoplastic polyether-polyamide copolymers and other thermoplastic resins (including thermoplastic elastomers). Also, resins obtained by irradiating a thermoplastic olefin copolymer or a thermoplastic polyolefin with an electron beam for crosslinking can be used. Among these, as the thermoplastic resin, thermoplastic olefin copolymers such as ethylene-propylene copolymer elastomers and ethylene-1-butene copolymer elastomers, thermoplastic polyamides such as nylon 6 and nylon 6 / 12, and thermoplastic polyether-polyolefin copolymers are preferred, and from the viewpoint of the separability of the adhesive layer 3, thermoplastic polyamides are more preferred. These thermoplastic resins may be used alone or in combination of two or more.

[0067] When the above-mentioned first resin layer, second resin layer, and other resin layers are composed of a mixed resin containing other resins other than the above-mentioned specific ionomer resin at a content ratio of 20% by mass or less, the Vicat softening temperature of the other resin is not particularly limited, but it is preferably appropriately selected so that the Vicat softening temperature of the mixed resin is in the range of 50°C or higher and less than 80°C. Further, when the other resin layer laminated on the first resin layer and the second resin layer is composed of other resins other than the resin containing the above-mentioned specific ionomer resin at a content ratio of 80% by mass or more, the Vicat softening temperature of the other resin is preferably in the range of 50°C or higher and less than 80°C.

[0068] <Other components> In the resin used for each resin layer constituting the base film 1 of the present embodiment, other components other than the resin according to the present embodiment can be contained as long as the effects of the present invention are not impaired. The other components are not particularly limited, and examples thereof include coupling agents, inorganic fillers, organic fillers, ultraviolet absorbers, antioxidants, light stabilizers, anti-aging agents, light diffusing agents, plasticizers, organic dyes, dyes, pigments, lubricants, impact resistance improvers, metal deactivators, flame retardants, flame retardant aids, slip agents, strengthening agents, release agents, and the like. The other components may be used alone or in combination of two or more. The content of these other components is not particularly limited, but should be kept within a range where the base film 1 exhibits the desired functions and does not lose its expandability and heat shrinkability.

[0069] <Total thickness of the base film and thickness of each resin layer> The total thickness of the base film 1 of the present embodiment is not particularly limited, but the lower limit is preferably 60 μm, more preferably 70 μm. On the other hand, the upper limit is preferably 150 μm, more preferably 120 μm. When the total thickness of the base film 1 is less than 60 μm, for example, the strength may be insufficient for holding the ring frame during dicing. On the other hand, when the total thickness of the base film 1 exceeds 150 μm, for example, the expandability may be inferior. In addition, when the base film 1 or the wafer processing adhesive tape 10 is wound in a long roll shape, step marks may occur in the winding core part.

[0070] In addition, the thickness of each resin layer containing the specific ionomer resin in the base film 1 at a content ratio of 80% by mass or more is not particularly limited, but the lower limit is preferably 10 μm, more preferably 20 μm. On the other hand, the upper limit is preferably 50 μm, more preferably 40 μm. The total thickness of all resin layers containing the specific ionomer resin at a content ratio of 80% by mass or more is not particularly limited, but the lower limit is preferably 65% of the total thickness of the base film 1, more preferably 80%, still more preferably 90%, and the upper limit is 100%. In the base film 1 adjusted in this way, the mechanical properties exhibited by the appropriate and advanced cross-linked structure of the specific ionomer resin are sufficiently reflected, so that the tensile stress during stretching, the uniform expandability, and the restoring force during heating with respect to the strain after stretching of the base film 1 are sufficient. As a result, the die bond film (adhesive layer) 3 is cut well, and the kerf width between individual semiconductor chips is also sufficiently ensured, so that good pick-up properties can be obtained.

[0071] In addition, for the base film 1 of the present embodiment, the thickness of each resin layer containing the specific ionomer resin in the base film 1 at a content ratio of 80% by mass or more is in the range of 10 μm or more and 50 μm or less, and it is preferable to laminate and form a film so that the total thickness of the base film 1 is in the range of 60 μm or more and 150 μm or less. In this case, compared with the case of forming and manufacturing the base film 1 having the same thickness with a single-layer structure, the extrusion flow rate can be controlled without excessively increasing the resin pressure and motor load in the extruder, so it is preferable from the viewpoints of film forming accuracy and stable film formation.

[0072] When another resin layer is further laminated on the first resin layer and the second resin layer of the base film 1, it is preferable to appropriately adjust the total thickness of the other resin layer so that the total thickness of the base film 1 is in the range of 60 μm or more and 150 μm or less. The total thickness of the other resin layer is preferably adjusted, for example, in the range of 0.6 μm or more and 52 μm or less.

[0073] <Method for manufacturing a base film> The method for manufacturing the base film 1 of the present embodiment is not particularly limited. For example, the resin composition for forming the first resin layer described above and the resin composition for forming the second resin layer are supplied to separate extruders, melted, and the T-die co-extrusion method or inflation co-extrusion method in which the respective molten resin compositions are extruded from one die can be used. When manufacturing the base film 1 having a structure of three or more layers, separate extruders corresponding to the number of layers may be used. Also, a method of extrusion laminating the second resin layer on the previously formed first resin layer, a method of extrusion laminating the second resin layer between two previously formed first resin layers, etc. can also be used. Among these, from the viewpoints of the uniform expandability and production efficiency of the base film 1, the T-die co-extrusion method is preferable. In the inflation co-extrusion method, since the resin is likely to be oriented, the uniform expandability may decrease. Also, in the extrusion lamination method, since it is necessary to previously form one layer into a film shape, the production efficiency deteriorates.

[0074] In addition, in the above T-die coextrusion method, it is desirable to adopt a T-die coextrusion - nip roll forming method using a nip roll having fine irregularities on its surface. When the resin composition is extruded from the T-die and sandwiched (nip roll formed) between a cooling roll and a nip roll having fine irregularities, for example, even if a resin layer containing the above specific ionomer resin having a low Vicat softening point is disposed as the outermost layer of the base film 1, due to the irregularities formed on the surface of the base film 1, the releasability of the resin layer from the roll during film formation of the base film 1 and during the production of the adhesive tape for wafer processing, and the blocking prevention property of the roll-shaped mother roll of the base film 1 after film formation and the adhesive tape for wafer processing after processing can be ensured.

[0075] <<Adhesive layer>> The adhesive tape 10 for wafer processing of the present invention has a configuration in which an adhesive layer 2 for holding (temporarily fixing) a semiconductor wafer is provided on one surface of the above-described base film 1. Further, a base sheet (release liner) having releasability may be provided on the surface of the adhesive layer 2 of the adhesive tape 10 for wafer processing (the surface opposite to the surface facing the base film 1). As the adhesive for forming the adhesive layer 2, for example, conventionally known adhesive compositions such as acrylic-based, silicone-based, polyester-based, polyvinyl acetate-based, polyurethane-based, and rubber-based can be used. Among these, from the viewpoints of versatility and practical reliability, an active energy ray curable acrylic-based adhesive composition that cures and shrinks by irradiation with active energy rays such as ultraviolet rays (UV) and thus reduces the adhesive force to the adherend is preferably used.

[0076] <Active energy ray curable acrylic-based adhesive composition> Examples of the active energy ray-curable acrylic pressure-sensitive adhesive composition typically include a pressure-sensitive adhesive composition (A) comprising an acrylic pressure-sensitive adhesive polymer having a photosensitive carbon-carbon double bond and a functional group (hereinafter sometimes referred to as "active energy ray-curable acrylic pressure-sensitive adhesive polymer"), a photopolymerization initiator, and a crosslinking agent that reacts with the functional group, or a pressure-sensitive adhesive composition (B) comprising an acrylic pressure-sensitive adhesive polymer having a functional group, an active energy ray-curable compound, a photopolymerization initiator, and a crosslinking agent that reacts with the functional group, etc., but are not particularly limited thereto. Among them, from the viewpoints of improving the peelability from the adhesive layer 3 and suppressing glue residue on the adhesive layer 3, the pressure-sensitive adhesive composition (A) comprising the active energy ray-curable acrylic pressure-sensitive adhesive polymer, the photopolymerization initiator, and the crosslinking agent that reacts with the functional group in the former aspect is preferred. Here, the functional group refers to a thermally reactive functional group that can coexist with a carbon-carbon double bond. Examples of such functional groups are active hydrogen groups such as hydroxyl group, carboxyl group, and amino group, and functional groups that react with active hydrogen groups such as glycidyl group. The active hydrogen group refers to a functional group having an element such as nitrogen, oxygen, or sulfur other than carbon and hydrogen directly bonded thereto.

[0077] <Adhesive composition (A)> [Acrylic pressure-sensitive adhesive polymer having a carbon-carbon double bond and a functional group] The above adhesive composition (A) contains an acrylic pressure-sensitive adhesive polymer having a photosensitive carbon-carbon double bond and a functional group, a photopolymerization initiator, and a crosslinking agent that reacts with the functional group. As the acrylic pressure-sensitive adhesive polymer having a carbon-carbon double bond and a functional group in the above adhesive composition (A), those having a carbon-carbon double bond introduced into the molecular side chain are used. The method for producing an acrylic pressure-sensitive adhesive polymer having a carbon-carbon double bond and a functional group is not particularly limited, but usually includes copolymerizing a (meth)acrylate ester and a functional group-containing unsaturated compound to obtain a copolymer, and adding a compound having a functional group capable of undergoing an addition reaction with the functional group and a carbon-carbon double bond possessed by the copolymer.

[0078] As the above copolymer (hereinafter sometimes referred to as "copolymer having a functional group") before subjecting the compound having the above functional group and a carbon-carbon double bond to an addition reaction, specifically, a copolymer containing a (meth)acrylic acid alkyl ester monomer, an active hydrogen group-containing monomer and / or a glycidyl group-containing monomer can be mentioned.

[0079] Examples of the above (meth)acrylic acid alkyl ester monomer include hexyl (meth)acrylate, n-octyl (meth)acrylate, isooctyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, nonyl (meth)acrylate, isononyl (meth)acrylate, decyl (meth)acrylate, isodecyl (meth)acrylate, undecyl (meth)acrylate, dodecyl (meth)acrylate, tridecyl (meth)acrylate, tetradecyl (meth)acrylate, pentadecyl (meth)acrylate, hexadecyl (meth)acrylate, heptadecyl (meth)acrylate, octadecyl (meth)acrylate, or monomers having 5 or less carbon atoms such as pentyl (meth)acrylate, n-butyl (meth)acrylate, isobutyl (meth)acrylate, ethyl (meth)acrylate, methyl (meth)acrylate and the like.

[0080] In addition, examples of the active hydrogen group-containing monomer include hydroxyl group-containing monomers such as 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, and 6-hydroxyhexyl (meth)acrylate; carboxyl group-containing monomers such as (meth)acrylic acid, itaconic acid, maleic acid, fumaric acid, crotonic acid, and isocrotonic acid; acid anhydride group-containing monomers such as maleic anhydride and itaconic anhydride; amide-based monomers such as (meth)acrylamide, N,N-dimethyl (meth)acrylamide, N-butyl (meth)acrylamide, N-methylol (meth)acrylamide, N-methylolpropane (meth)acrylamide, N-methoxymethyl (meth)acrylamide, and N-butoxymethyl (meth)acrylamide; amino group-containing monomers such as aminoethyl (meth)acrylate, N,N-dimethylaminoethyl (meth)acrylate, and t-butylaminoethyl (meth)acrylate. These active hydrogen group-containing monomer components may be used alone or in combination of two or more. Examples of the glycidyl group-containing monomer include glycidyl (meth)acrylate.

[0081] The content of the above heat-reactive functional group is not particularly limited, but it is preferably in the range of 0.5% by mass or more and 50% by mass or less based on the total amount of the copolymerizable monomer components.

[0082] Examples of suitable copolymers having functional groups obtained by copolymerizing the above monomers include, specifically, a binary copolymer of 2-ethylhexyl acrylate and acrylic acid, a binary copolymer of 2-ethylhexyl acrylate and 2-hydroxyethyl acrylate, a terpolymer of 2-ethylhexyl acrylate, methacrylic acid and 2-hydroxyethyl acrylate, a binary copolymer of n-butyl acrylate and acrylic acid, a binary copolymer of n-butyl acrylate and 2-hydroxyethyl acrylate, a terpolymer of n-butyl acrylate, methacrylic acid and 2-hydroxyethyl acrylate, a terpolymer of 2-ethylhexyl acrylate, methyl methacrylate and 2-hydroxyethyl acrylate, a quaternary copolymer of 2-ethylhexyl acrylate, n-butyl acrylate, 2-hydroxyethyl acrylate and methacrylic acid, a quaternary copolymer of 2-ethylhexyl acrylate, methyl methacrylate, 2-hydroxyethyl acrylate and methacrylic acid, etc., but are not particularly limited thereto.

[0083] The copolymer having the above functional group may contain other copolymer monomer components as necessary for the purpose of cohesion, heat resistance, etc. Specific examples of such other copolymer monomer components include, for example, cyano group-containing monomers such as (meth)acrylonitrile, olefin-based monomers such as ethylene, propylene, isoprene, butadiene, isobutylene, etc., styrene-based monomers such as styrene, α-methylstyrene, vinyltoluene, etc., vinyl ester-based monomers such as vinyl acetate, vinyl propionate, etc., vinyl ether-based monomers such as methyl vinyl ether, ethyl vinyl ether, etc., halogen atom-containing monomers such as vinyl chloride, vinylidene chloride, etc., alkoxy group-containing monomers such as (meth)acrylic acid methoxyethyl, (meth)acrylic acid ethoxyethyl, etc., monomers having a nitrogen atom-containing ring such as N-vinyl-2-pyrrolidone, N-methylvinylpyrrolidone, N-vinylpyridine, N-vinylpiperidone, N-vinylpyrimidine, N-vinylpiperazine, N-vinylpyrazine, N-vinylpyrrole, N-vinylimidazole, N-vinyl oxazole, N-vinylmorpholine, N-vinylcaprolactam, N-(meth)acryloylmorpholine, etc. These other copolymer monomer components may be used alone or in combination of two or more. The acrylic pressure-sensitive adhesive polymer having the above functional group preferably has a glass transition temperature (Tg) in the range of -70°C or higher and 15°C or lower, and more preferably in the range of -60°C or higher and -10°C or lower.

[0084] The acrylic pressure-sensitive polymer having the carbon-carbon double bond and the functional group can be obtained by using the copolymer having the above-described functional group and subjecting a compound having a functional group capable of undergoing an addition reaction with the functional group of the copolymer and a carbon-carbon double bond to an addition reaction. As such a compound having a functional group and a carbon-carbon double bond, for example, when an addition reaction is carried out with respect to the hydroxyl group in the side chain of the copolymer, 2-methacryloyloxyethyl isocyanate, 4-methacryloyloxy-n-butyl isocyanate, 2-acryloyloxyethyl isocyanate, m-isopropenyl-α,α-dimethylbenzyl isocyanate and other isocyanate compounds having a (meth)acryloyloxy group can be used. Further, when an addition reaction is carried out with respect to the carboxyl group in the side chain of the copolymer, glycidyl (meth)acrylate, 2-(1-aziridinyl)ethyl (meth)acrylate and the like can be used as the compound. Furthermore, when an addition reaction is carried out with respect to the glycidyl group in the side chain of the copolymer, (meth)acrylic acid and the like can be used as the compound.

[0085] From the viewpoints of ease of reaction tracking (stability of control) and technical difficulty, the most suitable addition reaction method is to subject a compound having an isocyanate group and a carbon-carbon double bond (an isocyanate compound having a (meth)acryloyloxy group) capable of undergoing an addition reaction with the hydroxyl group in the side chain of the copolymer to an addition reaction.

[0086] In addition, when performing the above addition reaction, in order to crosslink the active energy ray-curable acrylic pressure-sensitive adhesive polymer with a crosslinking agent such as a polyisocyanate-based crosslinking agent or an epoxy-based crosslinking agent described later and further increase the molecular weight, it is preferable to leave functional groups such as hydroxyl groups, carboxyl groups, and glycidyl groups. For example, when reacting an isocyanate compound having a (meth)acryloyloxy group with a copolymer having a hydroxyl group in the side chain, the equivalent ratio [(NCO) / (OH)] of the isocyanate group (-NCO) of the isocyanate compound having a (meth)acryloyloxy group to the hydroxyl group (-OH) in the side chain of the above copolymer may be adjusted so as to be less than 1.0. In this way, an acrylic pressure-sensitive adhesive polymer having a carbon-carbon double bond and a functional group such as a (meth)acryloyloxy group, that is, an active energy ray-curable acrylic pressure-sensitive adhesive polymer can be obtained.

[0087] In the above addition reaction, it is preferable to use a polymerization inhibitor so that the active energy ray reactivity of the carbon-carbon double bond is maintained. As such a polymerization inhibitor, a quinone-based polymerization inhibitor such as hydroquinone monomethyl ether is preferable. The amount of the polymerization inhibitor is not particularly limited, but it is preferably in the range of usually 0.01 part by mass or more and 0.1 part by mass or less with respect to the total amount of the copolymer having a functional group and the active energy ray-reactive compound.

[0088] The above-mentioned active energy ray-curable acrylic pressure-sensitive adhesive polymer preferably has a weight average molecular weight Mw in the range of 100,000 or more and 2,000,000 or less. When the weight average molecular weight Mw of the active energy ray-curable acrylic pressure-sensitive adhesive polymer is less than 100,000, it is difficult and not preferable to obtain a solution of an active energy ray-curable resin composition having a high viscosity of several thousand cP or more and several tens of thousands of cP or less in consideration of coatability and the like. In addition, the cohesive force of the adhesive layer 2 before irradiation with active energy rays becomes small. For example, when the semiconductor chip with the die bond film 3 is detached from the adhesive layer 2 after irradiation with active energy rays, the semiconductor wafer with the die bond film 3 may be contaminated. On the other hand, when the weight average molecular weight Mw exceeds 2,000,000, there are no particular problems in terms of the properties of the pressure-sensitive adhesive, but it is difficult to mass-produce the active energy ray-curable acrylic pressure-sensitive adhesive polymer. For example, the active energy ray-curable acrylic pressure-sensitive adhesive polymer may gel during synthesis, which is not preferable. The weight average molecular weight Mw of the active energy ray-curable acrylic pressure-sensitive adhesive polymer is more preferably 300,000 or more and 1,500,000 or less. Here, the weight average molecular weight Mw means a standard polystyrene conversion value measured by gel permeation chromatography.

[0089] The carbon-carbon double bond content of the acrylic pressure-sensitive polymer having the carbon-carbon double bond and the functional group only needs to be an amount that can obtain a sufficient adhesive force reduction effect in the adhesive layer 2 after irradiation with active energy rays. It varies depending on usage conditions such as the irradiation amount of active energy rays and is not uniquely defined. However, as the carbon-carbon double bond content, for example, it is preferably in the range of 0.85 meq / g or more and 1.60 meq / g or less. When the carbon-carbon double bond content is less than 0.85 meq / g, the adhesive force reduction effect in the adhesive layer 2 after irradiation with active energy rays becomes small, and there is a risk of an increase in the pickup failure of the semiconductor chip with the adhesive layer 3. On the other hand, when the carbon-carbon double bond content exceeds 1.60 meq / g, the fluidity of the adhesive becomes insufficient in the adhesive layer 2 after irradiation with active energy rays, the semiconductor chip gap after expansion of the dicing die bond film 20 does not widen sufficiently, and there is a risk of a problem that image recognition of each semiconductor chip becomes difficult during pickup. In addition, depending on the copolymer composition of the acrylic pressure-sensitive polymer, it may be likely to gel during polymerization or reaction during synthesis, and synthesis may become difficult. When confirming the carbon-carbon double bond content of the active energy ray-curable acrylic pressure-sensitive polymer, the carbon-carbon double bond content can be calculated by measuring the iodine value of the active energy ray-curable acrylic pressure-sensitive polymer.

[0090] [Photoinitiator] As described above, the above-mentioned active energy ray-curable acrylic pressure-sensitive adhesive composition (pressure-sensitive adhesive composition (A)) contains a photopolymerization initiator that generates radicals upon irradiation with active energy rays. The photopolymerization initiator senses the irradiation of active energy rays on the pressure-sensitive adhesive layer during adhesion removal, generates radicals, and initiates the crosslinking reaction of the carbon-carbon double bonds possessed by the active energy ray-curable acrylic pressure-sensitive polymer in the pressure-sensitive adhesive layer 2. As a result, under irradiation with active energy rays, the pressure-sensitive adhesive layer further cures and shrinks, thereby reducing the adhesive force to the adherend. As the photopolymerization initiator, a compound that generates radical active species by ultraviolet rays or the like is preferable. For example, alkylphenone-based radical polymerization initiators, acylphosphine oxide-based radical polymerization initiators, oxime ester-based radical polymerization initiators, and the like can be mentioned. These photopolymerization initiators may be used alone or in combination of two or more.

[0091] Examples of the alkylphenone-based radical polymerization initiator include benzyl methyl ketal-based radical polymerization initiators, α-hydroxyalkylphenone-based radical polymerization initiators, α-aminoalkylphenone-based radical polymerization initiators, and the like.

[0092] Specific examples of the benzyl methyl ketal-based radical polymerization initiator include, for example, 2,2'-dimethoxy-1,2-diphenylethane-1-one (e.g., trade name: Omnirad651, manufactured by IGM Resins B.V.). Specific examples of the α-hydroxyalkylphenone-based radical polymerization initiator include, for example, 2-hydroxy-2-methyl-1-phenylpropan-1-one (trade name: Omnirad1173, manufactured by IGM Resins B.V.), 1-hydroxycyclohexyl phenyl ketone (trade name: Omnirad184, manufactured by IGM Resins B.V.), 1-[4-(2-hydroxyethoxy)phenyl]-2-hydroxy-2-methyl-1-propan-1-one (trade name: Omnirad2959, manufactured by IGM Resins B.V.), 2-hydroxy-1-{4-[4-(2-hydroxy-2-methylpropionyl)benzyl]phenyl}-2-methylpropan-1-one (trade name Omnirad127, manufactured by IGM Resins B.V.), and the like. Specific examples of the α-aminoalkylphenone-based radical polymerization initiator include, for example, 2-methyl-1-(4-methylthiophenyl)-2-morpholinopropan-1-one (trade name: Omnirad907, manufactured by IGM Resins B.V.), 2-benzyl-2-(dimethylamino)-4'-morpholinobutyrophenone (trade name: Omnirad369, manufactured by IGM Resins B.V.), 2-dimethylamino-2-(4-methylbenzyl)-1-(4-morpholin-4-yl-phenyl)-butan-1-one (trade name: Omnirad379EG, manufactured by IGM Resins B.V.), and the like.

[0093] Specific examples of the acylphosphine oxide-based radical polymerization initiator include, for example, 2,4,6-trimethylbenzoyl-diphenylphosphine oxide (trade name: OmniradTPO, manufactured by IGM Resins B.V.), bis(2,4,6-trimethylbenzoyl)-phenylphosphine oxide (trade name: Omnirad819, manufactured by IGM Resins B.V.), and the like.

[0094] Examples of the oxime ester-based radical polymerization initiator include 1,2-octanedione, 1-[4-(phenylthio)phenyl]-, 2-(O-benzoyloxime) (trade name: Omnirad OXE-01, manufactured by IGM Resins B.V.).

[0095] The addition amount of the above photoinitiator is preferably in the range of 0.1 part by mass or more and 10.0 parts by mass or less with respect to 100 parts by mass of the solid content of the above active energy ray-curable acrylic pressure-sensitive adhesive polymer. When the addition amount of the photoinitiator is less than 0.1 part by mass, the photoreactivity with respect to the active energy ray is not sufficient, so that even when the active energy ray is irradiated, the photo-radical crosslinking reaction of the acrylic pressure-sensitive adhesive polymer does not occur sufficiently, and the curing and shrinkage of the adhesive become insufficient. As a result, the effect of reducing the adhesive force in the adhesive layer 2 after irradiation with the active energy ray becomes small, and there is a possibility that the pick-up failure of the semiconductor chip increases. On the other hand, when the addition amount of the photoinitiator exceeds 10.0 parts by mass, the effect is saturated, which is not preferable from the viewpoint of economy. In addition, depending on the type of the photoinitiator, the adhesive layer 2 may turn yellow and cause poor appearance.

[0096] In addition, as a sensitizer for such a photoinitiator, compounds such as dimethylaminoethyl methacrylate and isoamyl 4-dimethylaminobenzoate may be added to the adhesive.

[0097] [Crosslinking agent] As described above, the above-mentioned active energy ray-curable acrylic pressure-sensitive adhesive composition (pressure-sensitive adhesive composition (A)) further contains a crosslinking agent for increasing the molecular weight of the active energy ray-curable acrylic pressure-sensitive adhesive polymer. Such a crosslinking agent is not particularly limited, and a known crosslinking agent having a functional group capable of reacting with functional groups such as a hydroxyl group, a carboxyl group, and a glycidyl group, which are functional groups of the above-mentioned active energy ray-curable acrylic pressure-sensitive adhesive polymer, can be used. Specifically, for example, polyisocyanate-based crosslinking agents, epoxy-based crosslinking agents, aziridine-based crosslinking agents, melamine resin-based crosslinking agents, urea resin-based crosslinking agents, acid anhydride compound-based crosslinking agents, polyamine-based crosslinking agents, carboxyl group-containing polymer-based crosslinking agents, etc. can be mentioned. Among these, it is preferable to use a polyisocyanate-based crosslinking agent or an epoxy-based crosslinking agent from the viewpoints of reactivity and versatility. These crosslinking agents may be used alone or in combination of two or more. The blending amount of the crosslinking agent is preferably in the range of 0.01 part by mass or more and 15 parts by mass or less with respect to 100 parts by mass of the solid content of the active energy ray-curable acrylic pressure-sensitive adhesive polymer.

[0098] Examples of the above-mentioned polyisocyanate-based crosslinking agents include polyisocyanate compounds having an isocyanurate ring, adduct polyisocyanate compounds obtained by reacting trimethylolpropane with hexamethylene diisocyanate, adduct polyisocyanate compounds obtained by reacting trimethylolpropane with tolylene diisocyanate, adduct polyisocyanate compounds obtained by reacting trimethylolpropane with xylylene diisocyanate, adduct polyisocyanate compounds obtained by reacting trimethylolpropane with isophorone diisocyanate, etc. These can be used alone or in combination of two or more.

[0099] Examples of the epoxy crosslinking agent include bisphenol A-epichlorohydrin type epoxy resins, ethylene glycol diglycidyl ether, polyethylene glycol diglycidyl ether, glycerin diglycidyl ether, glycerin triglycidyl ether, 1,6-hexanediol diglycidyl ether, trimethylolpropane triglycidyl ether, sorbitol polyglycidyl ether, polyglycerol polyglycidyl ether, pentaerythritol polyglycidyl ether, diglycerol polyglycidyl ether, 1,3′-bis(N,N-diglycidylaminomethyl)cyclohexane, N,N,N′,N′-tetraglycidyl-m-xylenediamine, and the like. These can be used alone or in combination of two or more.

[0100] After forming the pressure-sensitive adhesive layer 2 with the above active energy ray curable resin composition (pressure-sensitive adhesive composition (A)), the aging conditions for reacting the above crosslinking agent with the active energy ray curable acrylic pressure-sensitive adhesive polymer having the above functional group are not particularly limited. For example, the temperature may be appropriately set in the range of 23°C or higher and 80°C or lower, and the time may be appropriately set in the range of 24 hours or longer and 168 hours or shorter.

[0101] [Others] The above active energy ray curable acrylic pressure-sensitive adhesive composition (pressure-sensitive adhesive composition (A)) may, within a range not impairing the effects of the present invention, optionally contain other additives such as polyfunctional acrylic monomers, polyfunctional acrylic oligomers, tackifiers, fillers, antioxidants, colorants, flame retardants, antistatic agents, surfactants, silane coupling agents, leveling agents, and the like.

[0102] [Pressure-sensitive adhesive composition (B)] [Acrylic pressure-sensitive adhesive polymer having a functional group] The above pressure-sensitive adhesive composition (B) contains an acrylic pressure-sensitive adhesive polymer having a functional group, an active energy ray curable compound, a photoinitiator, and a crosslinking agent that reacts with the functional group. As the acrylic pressure-sensitive adhesive polymer having a functional group in the above pressure-sensitive adhesive composition (B), the same ones as those exemplified as the acrylic pressure-sensitive adhesive polymer having a functional group in the description of the above active energy ray curable acrylic pressure-sensitive adhesive composition (pressure-sensitive adhesive composition (A)) can be used.

[0103] [Active energy ray curable compound] As the active energy ray curable compound in the above pressure-sensitive adhesive composition (B), for example, low molecular weight compounds having at least two carbon-carbon double bonds in the molecule that can be three-dimensionally crosslinked by irradiation with active energy rays are widely used. Specific examples of such low molecular weight compounds include esters of (meth)acrylic acid and polyhydric alcohols such as trimethylolpropane tri(meth)acrylate, pentaerythritol tri(meth)acrylate, tetraethylene glycol di(meth)acrylate, 1,6-hexanediol di(meth)acrylate, neopentyl glycol di(meth)acrylate, dipentaerythritol hexa(meth)acrylate; isocyanurates or isocyanurate compounds such as 2-propenyl-di-3-butenyl cyanurate, 2-hydroxyethyl bis(2-acryloxyethyl) isocyanurate, tris(2-methacryloxyethyl) isocyanurate. These active energy ray curable low molecular weight compounds may be used alone or in combination of two or more.

[0104] In addition to the low molecular weight compounds as described above, as the active energy ray curable compound, active energy ray curable oligomers such as epoxy acrylate oligomers, urethane acrylate oligomers, and polyester acrylate oligomers can also be used. Epoxy acrylate is synthesized by an addition reaction of an epoxy compound and (meth)acrylic acid. Urethane acrylate is synthesized, for example, by reacting an addition reaction product of a polyol and a polyisocyanate with a hydroxy group-containing (meth)acrylate to react the remaining isocyanate group at the terminal to introduce a (meth)acrylic group at the molecular terminal. Polyester acrylate is synthesized by a reaction of a polyester polyol and (meth)acrylic acid. From the viewpoint of the effect of reducing the adhesive strength of the adhesive layer 2 after irradiation with active energy rays, those having three or more carbon-carbon double bonds in the molecule are preferable for the above active energy ray curable oligomers. These active energy ray curable oligomers may be used alone or in combination of two or more.

[0105] The weight average molecular weight Mw of the above active energy ray curable oligomer is not particularly limited, but is preferably in the range of 100 or more and 30,000 or less, and more preferably in the range of 500 or more and 6,000 or less from the viewpoints of both suppression of contamination of the semiconductor chip and the effect of reducing the adhesive strength of the adhesive layer 2 after irradiation with active energy rays.

[0106] The content of the above active energy ray curable compound is preferably in the range of 5 parts by mass or more and 500 parts by mass or less, preferably 50 parts by mass or more and 180 parts by mass or less, based on 100 parts by mass of the acrylic pressure-sensitive adhesive polymer having a functional group. When the content of the above active energy ray curable compound is within the above range, the adhesive strength of the adhesive layer 2 can be appropriately reduced after irradiation with active energy rays, and pickup can be facilitated without damaging the semiconductor chip.

[0107] [Photoinitiator] The above-mentioned active energy ray-curable acrylic pressure-sensitive adhesive composition (pressure-sensitive adhesive composition (B)) contains a photopolymerization initiator that generates radicals upon irradiation with active energy rays. As the above-mentioned photopolymerization initiator, the same ones as those exemplified in the description of the above-mentioned active energy ray-curable acrylic pressure-sensitive adhesive composition (pressure-sensitive adhesive composition (A)) can be used. Also, the addition amount of the photopolymerization initiator may be the same.

[0108] [Crosslinking agent] The above-mentioned active energy ray-curable acrylic pressure-sensitive adhesive composition (pressure-sensitive adhesive composition (B)) further contains a crosslinking agent for increasing the molecular weight of the acrylic pressure-sensitive adhesive polymer having the above-mentioned functional groups. As the above-mentioned crosslinking agent, the same ones as those exemplified as crosslinking agents in the description of the above-mentioned active energy ray-curable acrylic pressure-sensitive adhesive composition (pressure-sensitive adhesive composition (A)) can be used. Also, the compounding amount of the crosslinking agent and the aging conditions for reacting the crosslinking agent with the acrylic pressure-sensitive adhesive polymer having functional groups may be the same.

[0109] [Others] The above-mentioned active energy ray-curable acrylic pressure-sensitive adhesive composition (pressure-sensitive adhesive composition (B)) may, within a range not impairing the effects of the present invention, optionally be added with other additives such as tackifiers, fillers, anti-aging agents, colorants, flame retardants, antistatic agents, surfactants, silane coupling agents, leveling agents, etc.

[0110] [Thickness of the pressure-sensitive adhesive layer] The thickness of the adhesive layer 2 of the wafer processing adhesive tape 10 of the present invention is not particularly limited, but is preferably in the range of 5 μm or more and 50 μm or less, more preferably in the range of 6 μm or more and 20 μm or less, and particularly preferably in the range of 7 μm or more and 15 μm or less. When the thickness of the adhesive layer 2 is less than 5 μm, the adhesive strength of the wafer processing adhesive tape 10 may be excessively reduced. In this case, in the cool expand process, the die bond film 3 is likely to peel off from the adhesive layer 2, and the yield of semiconductor chips is reduced. Also, when used as a dicing die bond film, poor adhesion may occur between the adhesive layer 2 and the die bond film 3. On the other hand, when the thickness of the adhesive layer 2 exceeds 50 μm, the internal stress generated when the wafer processing adhesive tape 10 is cool-expanded may be difficult to be transmitted as an external stress to the semiconductor wafer with the die bond film 3. In that case, in the dicing process, the dicing yield of the semiconductor chip with the die bond film 3 may be reduced. Also, the adhesion to the die bond film 3 becomes high, and from the viewpoint of economy, it is not very practical.

[0111] <<Anchor coat layer>> In the wafer processing adhesive tape 10 of the present embodiment, within a range that does not impair the effects of the present invention, an anchor coat layer adapted to the composition of the base film 1 may be provided between the base film 1 and the adhesive layer 2 according to the manufacturing conditions of the wafer processing adhesive tape 10 and the usage conditions of the wafer processing adhesive tape 10 after manufacturing. By providing the anchor coat layer, the adhesion between the base film 1 and the adhesive layer 2 is improved.

[0112] <<Release liner>> On the other hand, on the surface side (one surface side) opposite to the base film 1 of the adhesive layer 2, a release liner may be provided as needed. What can be used as the release liner is not particularly limited, and examples include synthetic resins such as polyethylene, polypropylene, and polyethylene terephthalate, and papers. Further, in order to enhance the releasability of the adhesive layer 2, the surface of the release liner may be subjected to a release treatment with a silicone-based release treatment agent, a long-chain alkyl-based release treatment agent, a fluorine-based release treatment agent, or the like. The thickness of the release liner is not particularly limited, but those in the range of 10 μm or more and 200 μm or less can be preferably used.

[0113] (Method for manufacturing an adhesive tape for wafer processing) FIG. 6 is a flowchart for explaining the method for manufacturing the adhesive tape 10 for wafer processing. First, a release liner is prepared (step S101: release liner preparation step). Next, a coating solution for the adhesive layer 2 (coating solution for forming the adhesive layer), which is a forming material for the adhesive layer 2, is prepared (step S102: coating solution preparation step). The coating solution can be prepared, for example, by uniformly mixing and stirring an acrylic adhesive polymer, a crosslinking agent, and a diluting solvent, which are components of the adhesive layer 2. As the solvent, for example, general-purpose organic solvents such as toluene and ethyl acetate can be used.

[0114] Then, using the coating solution for the adhesive layer 2 prepared in step S102, the coating solution is applied onto the release treatment surface of the release liner and dried to form an adhesive layer 2 with a predetermined thickness (step S103: adhesive layer forming step). The coating method is not particularly limited, and for example, it can be applied using a die coater, comma coater (registered trademark), gravure coater, roll coater, reverse coater, etc. Also, the drying conditions are not particularly limited, but for example, the drying temperature is preferably in the range of 80°C or higher and 150°C or lower, and the drying time is preferably in the range of 0.5 minutes or more and 5 minutes or less. Subsequently, a base film 1 is prepared (step S104: base film preparation step). Then, the base film 1 is bonded onto the adhesive layer 2 formed on the release liner (step S105: base film bonding step). Finally, the formed adhesive layer 2 is aged, for example, in an environment of 40°C for 72 hours to react the acrylic pressure-sensitive adhesive polymer and the crosslinking agent to effect crosslinking and curing (step S106: thermosetting step). Through the above steps, an adhesive tape 10 for wafer processing provided with an adhesive layer 2 and a release liner in this order from the base film side on the base film 1 can be manufactured. In the present invention, a laminate having a release liner on the adhesive layer 2 may also be referred to as the adhesive tape 10 for wafer processing.

[0115] Note that, as a method of forming the adhesive layer 2 on the base film 1, a method of applying the coating solution for the adhesive layer 2 onto the release liner, drying it, and then bonding the base film 1 onto the adhesive layer 2 was exemplified, but a method of directly applying the coating solution for the adhesive layer 2 onto the base film 1 and drying it may also be used. From the viewpoint of stable production, the former method is preferably used.

[0116] The adhesive tape 10 for wafer processing of the present embodiment may be in a form wound in a roll shape or a form in which wide sheets are laminated. Also, it may be in a sheet-like or tape-like form formed by cutting the adhesive tape 10 for wafer processing of these forms into a predetermined size in advance.

[0117] (Dicing Die Bond Film) This In the semiconductor manufacturing process, the wafer processing adhesive tape 10 of the embodiment can also be used in the form of a so-called dicing die bond film 20 in which a die bond film (adhesive layer) 3 is detachably adhered and laminated on the adhesive layer 2 of the wafer processing adhesive tape 10. The die bond film (adhesive layer) 3 is for adhering and connecting semiconductor chips cut and separated by cool expansion to a lead frame or a wiring board (support substrate). Also, when laminating semiconductor chips, it also serves as an adhesive layer between the semiconductor chips. In this case, the first-stage semiconductor chip is adhered to the wiring board for mounting a semiconductor chip with terminals formed thereon by the die bond film (adhesive layer) 3, and on the first-stage semiconductor chip, a second-stage semiconductor chip is further adhered by the die bond film (adhesive layer) 3. The connection terminals of the first-stage semiconductor chip and the second-stage semiconductor chip are electrically connected to external connection terminals via wires. However, the wires for the first-stage semiconductor chip are embedded in the die bond film (adhesive layer) 3, that is, the above-mentioned wire-embedded die bond film (adhesive layer) 3 during crimping (die bonding). Hereinafter, an example of the die bond film (adhesive layer) 3 when the wafer processing adhesive tape (dicing tape) 10 of the present embodiment is used in the form of the dicing die bond film 20 will be shown, but it is not particularly limited to this example.

[0118] <<Die Bond Film (Adhesive Layer)>> The above die bond film (adhesive layer) 3 is a layer made of a thermosetting adhesive composition that cures by heat. The adhesive composition is not particularly limited, and conventionally known materials can be used. As an example of a preferred embodiment of the adhesive composition, for example, a resin composition containing a glycidyl group-containing (meth)acrylate copolymer as a thermoplastic resin, an epoxy resin as a thermosetting resin, and a phenolic resin as a curing agent for the epoxy resin, with a curing accelerator, an inorganic filler, a silane coupling agent, etc. added thereto, is a thermosetting adhesive composition. The die bond film (adhesive layer) 3 made of such a thermosetting adhesive composition is excellent in adhesiveness between the semiconductor chip / support substrate and between the semiconductor chip / semiconductor chip, can also impart electrode embedding property and / or wire embedding property, etc., can be adhered at a low temperature in the die bonding process, and excellent curing can be obtained in a short time, and has characteristics such as excellent reliability after being molded by a sealing agent, which is preferable.

[0119] The general-purpose die bond film used in a form where the wire is not embedded in the adhesive layer and the wire-embedded type die bond film used in a form where the wire is embedded in the adhesive layer are often substantially the same in terms of the types of materials constituting the adhesive composition, but by changing the blending ratio of the materials used, the physical properties and characteristics of each material, etc. according to each purpose, they are customized for general-purpose die bond films or wire-embedded type die bond films. Also, when there is no problem with the reliability of the final semiconductor device, the wire-embedded type die bond film may be used as a general-purpose die bond film. That is, the wire-embedded type die bond film is not limited to wire embedding applications, and can be similarly used for applications such as adhering a semiconductor chip to a substrate having unevenness due to wiring, etc., a metal substrate such as a lead frame.

[0120] <Adhesive Composition for General-Purpose Die Bond Film> First, an example of an adhesive composition for a general-purpose die bond film will be described, but it is not particularly limited to this example. As an index of the fluidity of the die bond film 3 formed from the adhesive composition during die bonding, for example, the shear viscosity characteristics at 80°C can be mentioned. In the case of a general-purpose die bond film, generally, the shear viscosity at 80°C shows values in the range of 20,000 Pa·s or more and 40,000 Pa·s or less, preferably in the range of 25,000 Pa·s or more and 35,000 Pa·s or less. The shear viscosity at 80°C described above is a value measured by the following method. The die bond film (adhesive layer) 3 is laminated by bonding a plurality of sheets at 70°C so that the total thickness becomes 200 to 210 μm to produce a laminate. Next, the laminate is punched out into a size of 10 mm × 10 mm in the thickness direction to obtain a measurement sample. Subsequently, using a dynamic viscoelasticity device ARES (manufactured by Rheometric Scientific F.E. Co., Ltd.), after attaching a circular aluminum plate jig with a diameter of 8 mm, the measurement sample is set. While applying a 5% strain to the measurement sample at 35°C, the shear viscosity is measured while heating the measurement sample at a heating rate of 5°C / min, and the value of the shear viscosity at 80°C is obtained.

[0121] As an example of a preferred embodiment of the above-mentioned adhesive composition for a general-purpose die bond film, when the total amount of the glycidyl group-containing (meth)acrylate copolymer, the epoxy resin, and the phenol resin, which are the resin components of the adhesive composition, is taken as 100 parts by mass as a reference, (a) the glycidyl group-containing (meth)acrylate copolymer is included in the range of 52 parts by mass or more and 90 parts by mass or less, the epoxy resin is included in the range of 5 parts by mass or more and 25 parts by mass or less, and the phenol resin is included in the range of 5 parts by mass or more and 23 parts by mass or less, and the total amount of the resin components is adjusted to 100 parts by mass, (b) the curing accelerator is included in the range of 0.1 part by mass or more and 0.3 part by mass or less with respect to 100 parts by mass of the total amount of the epoxy resin and the phenol resin, and (c) an inorganic filler is included in the range of 5 parts by mass or more and 20 parts by mass or less with respect to 100 parts by mass of the total amount of the glycidyl group-containing (meth)acrylate copolymer, the epoxy resin, and the phenol resin.

[0122] [Glycidyl Group-containing (Meth)acrylate Copolymer] The glycidyl group-containing (meth)acrylate copolymer preferably contains, as copolymer units, at least (meth)acrylate alkyl ester having an alkyl group with 1 to 8 carbon atoms and glycidyl (meth)acrylate. From the viewpoint of ensuring appropriate adhesive strength, the copolymer unit of glycidyl (meth)acrylate is preferably contained in the total amount of the glycidyl group-containing (meth)acrylate copolymer in the range of 0.5% by mass or more and 6.0% by mass or less, and more preferably in the range of 2.0% by mass or more and 4.0% by mass or less. Further, the glycidyl group-containing (meth)acrylate copolymer may contain other monomers such as styrene and acrylonitrile as copolymer units, if necessary, from the viewpoint of adjusting the glass transition temperature (Tg).

[0123] The glass transition temperature (Tg) of the glycidyl group-containing (meth)acrylate copolymer is preferably in the range of -50°C or higher and 30°C or lower, and more preferably in the range of -10°C or higher and 30°C or lower from the viewpoint of improving the handleability (suppressing tackiness) as a die bond film. To make the glycidyl group-containing (meth)acrylate copolymer have such a glass transition temperature, it is preferable to use ethyl (meth)acrylate and / or butyl (meth)acrylate as the (meth)acrylate alkyl ester having an alkyl group with 1 to 8 carbon atoms.

[0124] The weight average molecular weight Mw of the glycidyl group-containing (meth)acrylate copolymer is preferably in the range of 500,000 or more and 2,000,000 or less, and more preferably in the range of 700,000 or more and 1,000,000 or less. When the weight average molecular weight Mw is within the above range, it is easy to make the adhesive strength, heat resistance, and flowability appropriate. Here, the weight average molecular weight Mw means the standard polystyrene conversion value measured by gel permeation chromatography.

[0125] The content ratio of the glycidyl group-containing (meth)acrylic acid ester copolymer in the die bond film (adhesive layer) 3 is preferably in the range of 52 mass% or more and 90 mass% or less, and more preferably in the range of 60 mass% or more and 80 mass% or less, based on 100 mass parts as the total amount of the glycidyl group-containing (meth)acrylic acid ester copolymer, which is the resin component in the adhesive composition, and the epoxy resin and phenolic resin described below.

[0126] [Epoxy resin] The epoxy resin is not particularly limited, but examples thereof include bisphenol A type epoxy resin, bisphenol F type epoxy resin, bisphenol S type epoxy resin, alicyclic epoxy resin, aliphatic chain epoxy resin, phenol novolac type epoxy resin, alkylphenol novolac type epoxy resin, cresol novolac type epoxy resin, bisphenol A novolac type epoxy resin, biphenol diglycidyl epoxy resin, and the like. ル Etherification products, diglycidyl naphthalene diol ル Ethers, diglycidyl phenols ル Examples of the epoxy resins include bifunctional epoxy resins such as etherified products, diglycidyl etherified products of alcohols, and alkyl-substituted, halogenated, and hydrogenated products thereof, and novolac-type epoxy resins. Other commonly known epoxy resins such as polyfunctional epoxy resins and heterocycle-containing epoxy resins may also be used. These may be used alone or in combination of two or more.

[0127] From the viewpoints of adhesive strength and heat resistance, the softening point of the epoxy resin is preferably in the range of 70° C. or more and 130° C. or less. Moreover, from the viewpoint of sufficiently proceeding with the curing reaction with the phenolic resin described below, the epoxy equivalent of the epoxy resin is preferably in the range of 100 or more and 300 or less.

[0128] From the perspective of appropriately expressing the function as a thermosetting adhesive in the die bond film (adhesive layer) 3, when the total amount of the glycidyl group-containing (meth)acrylate copolymer, the epoxy resin, and the phenolic resin described later, which are resin components in the adhesive composition, is taken as 100 parts by mass as a reference, the content ratio of the epoxy resin in the die bond film (adhesive layer) 3 is preferably in the range of 5% by mass or more and 25% by mass or less, and more preferably in the range of 10% by mass or more and 20% by mass or less.

[0129] [Phenolic resin: Curing agent for epoxy resin] The curing agent for the epoxy resin is not particularly limited. For example, a phenolic resin obtained by reacting a phenolic compound with a xylylene compound, which is a divalent linking group, in the absence or presence of an acid catalyst can be mentioned. Examples of the phenolic resin include novolak-type phenolic resins, resol-type phenolic resins, and polyoxy styrenes such as polyparaoxystyrene. Examples of the novolak-type phenolic resin include phenol novolak resin, phenol aralkyl resin, cresol novolak resin, tert-butylphenol novolak resin, and nonylphenol novolak resin. These phenolic resins may be used alone or in combination of two or more. Among these phenolic resins, phenol novolak resin and phenol aralkyl resin are preferably used because they tend to improve the connection reliability of the die bond film (adhesive layer) 3.

[0130] From the viewpoints of adhesive strength and heat resistance, the softening point of the phenolic resin is preferably in the range of 70°C or higher and 90°C or lower. Also, from the viewpoint of allowing the curing reaction with the epoxy resin to proceed sufficiently, the hydroxyl equivalent of the phenolic resin is preferably in the range of 100 or more and 200 or less.

[0131] From the viewpoint of allowing the curing reaction between the epoxy resin and the phenol resin in the above thermosetting resin composition to proceed sufficiently, the phenol resin is preferably blended in an amount such that the hydroxyl group in the total phenol resin component is preferably in the range of 0.5 equivalent or more and 2.0 equivalents or less, more preferably 0.8 equivalent or more and 1.2 equivalents or less, per equivalent of the epoxy group in the total epoxy resin component. Since it depends on the functional group equivalent of each resin, it cannot be generally stated, but for example, when the total amount of the glycidyl group-containing (meth)acrylate copolymer, the epoxy resin, and the phenol resin, which are resin components in the adhesive composition, is taken as 100 parts by mass as a reference, the content ratio of the phenol resin is preferably in the range of 5% by mass or more and 23% by mass or less.

[0132] [Curing accelerator] In addition, a curing accelerator such as a tertiary amine, imidazoles, or quaternary ammonium salts can be added to the above thermosetting resin composition as needed. Specific examples of such curing accelerators include, for example, 2-methylimidazole, 2-ethyl-4-methylimidazole, 1-cyanoethyl-2-phenylimidazole, 1-cyanoethyl-2-phenylimidazolium trimellitate, etc. These may be used alone or in combination of two or more. The addition amount of the above curing accelerator is preferably in the range of 0.1 part by mass or more and 0.3 part by mass or less with respect to 100 parts by mass in total of the above epoxy resin and the above phenol resin.

[0133] [Inorganic filler] Furthermore, from the viewpoint of controlling the fluidity of the die bond film (adhesive layer) 3 and improving the elastic modulus, an inorganic filler can be added to the above thermosetting resin composition as needed. Examples of the inorganic filler include aluminum hydroxide, magnesium hydroxide, calcium carbonate, magnesium carbonate, calcium silicate, magnesium silicate, calcium oxide, magnesium oxide, aluminum oxide, aluminum nitride, aluminum borate whisker, boron nitride, crystalline silica, amorphous silica, etc. These can be used alone or in combination of two or more. Among these, from the viewpoint of versatility, crystalline silica, amorphous silica, etc. are preferably used. Specifically, for example, Aerosil (registered trademark: ultrafine dry silica) having a nano-sized average particle diameter is preferably used. The content ratio of the inorganic filler in the die bond film (adhesive layer) 3 is preferably in the range of 5% by mass or more and 20% by mass or less based on 100 parts by mass in total of the glycidyl group-containing (meth)acrylate copolymer, epoxy resin, and phenol resin which are the above-described resin components.

[0134] [Silane coupling agent] Furthermore, from the viewpoint of improving the adhesive strength to the adherend, a silane coupling agent can be added to the above thermosetting resin composition as needed. Examples of the silane coupling agent include β-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, γ-glycidoxypropyltrimethoxysilane, and γ-glycidoxypropylmethyldiethoxysilane. These can be used alone or in combination of two or more. The addition amount of the silane coupling agent is preferably in the range of 1.0 part by mass or more and 7.0 part by mass or less with respect to 100 parts by mass in total of the above epoxy resin and the above phenol resin.

[0135] [Others] Furthermore, in the above thermosetting resin composition, a flame retardant, an ion trap agent, etc. may be added as long as the function as a die bond film is not impaired. Examples of the flame retardant include antimony trioxide, antimony pentoxide, and brominated epoxy resin. Examples of the ion trap agent include hydrotalcites, bismuth hydroxide, antimony hydroxide hydrate, zirconium phosphate with a specific structure, magnesium silicate, aluminum silicate, triazole-based compounds, tetrazole-based compounds, and bipyridyl-based compounds.

[0136] <Adhesive Composition for Wire-Embedded Die Bond Film> Subsequently, an example of the adhesive composition for a wire-embedded die bond film will be described, but it is not particularly limited to this example. As an index of the fluidity during die bonding of the die bond film 3 formed from the adhesive composition, for example, the shear viscosity characteristics at 80°C can be mentioned. In the case of a wire-embedded die bond film, generally, the shear viscosity at 80°C shows values in the range of 200 Pa·s or more and 11,000 Pa·s or less, preferably in the range of 2,000 Pa·s or more and 7,000 Pa·s or less.

[0137] As an example of a preferred embodiment of the above-described adhesive composition for a wire-embedded die bond film, when the total amount of the glycidyl group-containing (meth)acrylate copolymer, the epoxy resin, and the phenol resin, which are the resin components of the adhesive composition, is 100 parts by mass as a reference, (a) the glycidyl group-containing (meth)acrylate copolymer is in the range of 17 parts by mass or more and 51 parts by mass or less, the epoxy resin is in the range of 30 parts by mass or more and 64 parts by mass or less, and the phenol resin is in the range of 19 parts by mass or more and 53 parts by mass or less, and is adjusted and contained so that the total amount of the resin components is 100 parts by mass, (b) a curing accelerator is contained in the range of 0.01 parts by mass or more and 0.07 parts by mass or less with respect to 100 parts by mass of the total amount of the epoxy resin and the phenol resin, and (c) an inorganic filler is contained in the range of 10 parts by mass or more and 80 parts by mass or less with respect to 100 parts by mass of the total amount of the glycidyl group-containing (meth)acrylate copolymer, the epoxy resin, and the phenol resin.

[0138] [Glycidyl group-containing (meth)acrylate copolymer] The above glycidyl group-containing (meth)acrylate copolymer preferably contains, as copolymer units, at least a (meth)acrylic acid alkyl ester having an alkyl group having 1 to 8 carbon atoms and glycidyl (meth)acrylate. In the case of a wire-embedded die bond film, since it is necessary to achieve both improved fluidity during die bonding and ensured adhesive strength after curing, a glycidyl group-containing (meth)acrylate copolymer (A) having a high copolymer unit ratio of glycidyl (meth)acrylate and a low molecular weight and a glycidyl group-containing (meth)acrylate copolymer (B) having a low copolymer unit ratio of glycidyl (meth)acrylate and a high molecular weight are preferably used in combination, and it is preferable that the former component (A) is contained in a certain amount or more in the combination.

[0139] That is, the glycidyl group-containing (meth)acrylate copolymer in the adhesive composition for wire-embedded die bond film is specifically "(a copolymer unit of glycidyl (meth)acrylate is contained in the total amount of the glycidyl group-containing (meth)acrylate copolymer in the range of 5.0% by mass or more and 15.0% by mass or less, the glass transition temperature (Tg) is in the range of -50°C or more and 30°C or less, and the weight average molecular weight Mw is in the range of 100,000 or more and 400,000 or less glycidyl group-containing (meth)acrylate copolymer (A))" and "(a copolymer unit of glycidyl (meth)acrylate is contained in the total amount of the glycidyl group-containing (meth)acrylate copolymer in the range of 1.0% by mass or more and 7.0% by mass or less, the glass transition temperature (Tg) is in the range of -50°C or more and 30°C or less, and the weight average molecular weight Mw is in the range of 500,000 or more and 900,000 or less glycidyl group-containing (meth)acrylate copolymer (B))" and is preferably composed of a mixture thereof. Here, the weight average molecular weight Mw means a standard polystyrene conversion value measured by gel permeation chromatography.

[0140] The content ratio of the glycidyl group-containing (meth)acrylate copolymer (A) is preferably in the range of 60% by mass or more and 90% by mass or less in the total amount of the glycidyl group-containing (meth)acrylate copolymer (the total of (A) and (B)). Further, the glycidyl group-containing (meth)acrylate copolymer may contain other monomers such as styrene and acrylonitrile as copolymer units, if necessary, from the viewpoint of adjusting the glass transition temperature (Tg).

[0141] The glass transition temperature (Tg) of the entire glycidyl group-containing (meth)acrylic acid ester copolymer is preferably in the range of -50°C or higher and 30°C or lower, and more preferably in the range of -10°C or higher and 30°C or lower from the viewpoint of improving the handleability (suppressing tackiness) as a die bond film. To obtain such a glass transition temperature for the glycidyl group-containing (meth)acrylic acid ester copolymer, as the (meth)acrylic acid alkyl ester having an alkyl group with 1 to 8 carbon atoms, it is preferable to use ethyl (meth)acrylate and / or butyl (meth)acrylate.

[0142] The content ratio of the total amount of the glycidyl group-containing (meth)acrylic acid ester copolymer (the total of (A) and (B)) in the above wire-embedded die bond film (adhesive layer) 3 is, from the viewpoints of fluidity during die bonding and adhesive strength after curing, when the total amount of the glycidyl group-containing (meth)acrylic acid ester copolymer, which is a resin component in the adhesive composition, and the epoxy resin and phenol resin described below is taken as 100 parts by mass as a reference, preferably in the range of 17% by mass or more and 51% by mass or less, and more preferably in the range of 20% by mass or more and 45% by mass or less.

[0143] [Epoxy resin] The epoxy resin is not particularly limited, but the same ones as those exemplified as the epoxy resin for the general-purpose die bond film adhesive composition described above can be used. These can be used alone or in combination of two or more. However, in the case of a wire-embedded die bond film, it is necessary to ensure adhesive strength, suppress the generation of voids on the adhesive surface, and impart good embeddability of the wire. Therefore, in controlling its fluidity and elastic modulus, it is preferable to use a combination of two or more epoxy resins.

[0144] As a preferred embodiment of the epoxy resin used for the wire-embedded die bond film (adhesive layer) 3, those composed of a mixture of an epoxy resin (C) that is liquid at room temperature and an epoxy resin (D) having a softening point of 98°C or lower, preferably 85°C or lower, can be mentioned. The content ratio of the above-mentioned epoxy resin (C) that is liquid at room temperature is preferably in the range of 15% by mass or more and 75% by mass or less, more preferably in the range of 30% by mass or more and 50% by mass or less, in the total amount of the epoxy resin ((C) and (D)). From the viewpoint of allowing the curing reaction with the phenolic resin described later to proceed sufficiently, the epoxy equivalent of the above epoxy resin is preferably in the range of 100 or more and 300 or less.

[0145] From the viewpoint of appropriately expressing the function as a thermosetting adhesive in the die bond film (adhesive layer) 3, when the total amount of the above glycidyl group-containing (meth)acrylate copolymer, the epoxy resin, and the phenolic resin described later, which are resin components in the adhesive composition, is taken as 100 parts by mass as a reference, the content ratio of the above epoxy resin in the die bond film (adhesive layer) 3 is preferably in the range of 30% by mass or more and 64% by mass or less, more preferably in the range of 35% by mass or more and 50% by mass or less.

[0146] [Phenolic resin: Curing agent for epoxy resin] The curing agent for the epoxy resin is not particularly limited, but the same ones as those exemplified as the phenolic resin for the above-mentioned general-purpose die bond film adhesive composition can be used in the same manner. From the viewpoints of adhesive strength and fluidity, the softening point of the above phenolic resin is preferably in the range of 70°C or higher and 115°C or lower. Also, from the viewpoint of allowing the curing reaction with the epoxy resin to proceed sufficiently, the hydroxyl equivalent of the above phenolic resin is preferably in the range of 100 or more and 200 or less.

[0147] From the viewpoint of allowing the curing reaction between the epoxy resin and the phenolic resin in the above thermosetting resin composition to proceed sufficiently, in the phenolic resin, per equivalent of epoxy groups in all epoxy resin components, the hydroxyl groups in all the phenolic resin components are preferably in an amount in the range of 0.5 equivalents or more and 2.0 equivalents or less, and more preferably in the range of 0.6 equivalents or more and 1.0 equivalent or less, from the viewpoint of achieving compatibility with the fluidity during die bonding. Since it depends on the functional group equivalent of each resin, it cannot be generally stated, but for example, when the total amount of the glycidyl group-containing (meth)acrylate copolymer, the epoxy resin, and the phenolic resin, which are resin components in the adhesive composition, is taken as 100 parts by mass as a reference, the content ratio of the phenolic resin is preferably in the range of 19% by mass or more and 53% by mass or less.

[0148] [Curing accelerator] Further, a curing accelerator such as a tertiary amine, imidazoles, quaternary ammonium salts, etc. can be added to the above thermosetting resin composition as required. As such a curing accelerator, the same ones as those exemplified as the curing accelerator for the general-purpose die bond film adhesive composition can be used in the same manner. The addition amount of the above curing accelerator is preferably in the range of 0.01 part by mass or more and 0.07 part by mass or less with respect to 100 parts by mass in total of the above epoxy resin and the above phenolic resin, from the viewpoint of suppressing the generation of voids on the adhesive surface.

[0149] [Inorganic filler] Furthermore, from the viewpoints of improving the handleability of the die bond film (adhesive layer) 3, adjusting the fluidity during die bonding, imparting thixotropic properties, and improving the adhesive strength, an inorganic filler can be added to the thermosetting resin composition as needed. As the inorganic filler, the same ones as those exemplified as the inorganic fillers for the general-purpose die bond film adhesive composition can be used in the same manner. Among these, from the viewpoint of versatility, a silica filler is preferably used. The content ratio of the inorganic filler in the die bond film (adhesive layer) 3 is preferably in the range of 10% by mass or more and 80% by mass or less, more preferably in the range of 15% by mass or more and 50% by mass or less, based on 100 parts by mass of the total amount of the glycidyl group-containing (meth)acrylate copolymer, epoxy resin, and phenol resin, which are the resin components described above, from the viewpoints of fluidity during die bonding, cutability during cool expansion, and adhesive strength.

[0150] For the purpose of improving the cutability of the die bond film (adhesive layer) 3 during cool expansion and fully expressing the adhesive force after curing, it is preferable to mix two or more types of inorganic fillers having different average particle diameters. Specifically, it is preferable to use an inorganic filler having an average particle diameter in the range of 0.1 μm or more and 5 μm or less as the main inorganic filler component accounting for 80% by mass or more based on the total mass of the inorganic filler. When it is necessary to suppress the foaming of the adhesive layer 3 in the semiconductor chip manufacturing process due to excessive fluidity of the die bond film (adhesive layer) 3 and improve the adhesive strength after curing, an inorganic filler having an average particle diameter of less than 0.1 μm may be used in combination with the above main inorganic filler component in a blending amount of 20% by mass or less based on the total mass of the inorganic filler.

[0151] [Silane coupling agent] Furthermore, from the viewpoint of improving the adhesion to the adherend, a silane coupling agent can be added to the above thermosetting resin composition as needed. As the silane coupling agent, the same ones as those exemplified as the silane coupling agents for the above-mentioned general-purpose die bond film adhesive composition can be used in the same manner. The addition amount of the above silane coupling agent is preferably in the range of 0.5 parts by mass or more and 2.0 parts by mass or less with respect to 100 parts by mass in total of the above epoxy resin and the above phenolic resin from the viewpoint of suppressing the generation of voids on the adhesion surface.

[0152] [Others] Furthermore, a flame retardant, an ion trap agent, etc. may be added to the above thermosetting resin composition as long as the function as the die bond film 3 is not impaired. As these flame retardants and ion trap agents, the same ones as those exemplified as the flame retardants and ion trap agents for the above-mentioned general-purpose die bond film adhesive composition can be used in the same manner.

[0153] <Thickness of Die Bond Film> The thickness of the above die bond film (adhesive layer) 3 is not particularly limited, but is preferably in the range of 5 μm or more and 200 μm or less in order to ensure the adhesion strength, appropriately embed the wires for semiconductor chip connection, or sufficiently fill the unevenness of the wiring circuit of the substrate. If the thickness of the die bond film (adhesive layer) 3 is less than 5 μm, the adhesion between the semiconductor chip and the lead frame, wiring board, etc. may be insufficient. On the other hand, if the thickness of the die bond film (adhesive layer) 3 exceeds 200 μm, it becomes uneconomical and it is likely to be insufficient in coping with the miniaturization and thinning of the semiconductor device. In addition, in terms of high adhesiveness and the ability to thin the semiconductor device, the film thickness of the film-like adhesive is more preferably in the range of 10 μm or more and 100 μm or less, and particularly preferably in the range of 20 μm or more and 75 μm or less.

[0154] More specifically, when used as a general-purpose die bond film (adhesive layer), the thickness is preferably in the range of, for example, 5 μm or more and less than 30 μm, particularly preferably in the range of 10 μm or more and 25 μm or less. When used as a wire-embedded die bond film (adhesive layer), the thickness is preferably in the range of, for example, 30 μm or more and 100 μm or less, particularly preferably in the range of 40 μm or more and 80 μm or less.

[0155] (Method for manufacturing die bond film) The above die bond film (adhesive layer) 3 is manufactured, for example, as follows. First, a release liner is prepared. Note that the same release liner as the one disposed on the adhesive layer 2 of the wafer processing adhesive tape (dicing tape) 10 can be used. Next, a coating solution for the die bond film (adhesive layer) 3, which is a forming material of the die bond film (adhesive layer) 3, is prepared. The coating solution can be prepared, for example, by uniformly mixing and dispersing a thermosetting resin composition containing a glycidyl group-containing (meth)acrylate copolymer, an epoxy resin, a curing agent for the epoxy resin, an inorganic filler, a curing accelerator, and a silane coupling agent, etc., which are the constituent components of the die bond film (adhesive layer) 3 as described above, and a diluting solvent. As the solvent, for example, general-purpose organic solvents such as methyl ethyl ketone and cyclohexanone can be used.

[0156] Next, a coating solution for the die bond film (adhesive layer) 3 is applied onto the release treatment surface of the above-mentioned release liner serving as a temporary support, and then dried to form a die bond film (adhesive layer) 3 with a predetermined thickness. Thereafter, the release treatment surface of another release liner is bonded onto the die bond film (adhesive layer) 3. The coating method is not particularly limited, and for example, it can be applied using a die coater, comma coater (registered trademark), gravure coater, roll coater, reverse coater, or the like. Also, as the drying conditions, for example, it is preferable that the drying temperature is within the range of 60°C or higher and 200°C or lower, and the drying time is within the range of 1 minute or longer and 90 minutes or shorter. In the present invention, a laminate having a release liner on both sides or one side of the die bond film (adhesive layer) 3 may also be referred to as the die bond film (adhesive layer) 3 in some cases.

[0157] (Method for manufacturing dicing die bond film) The method for manufacturing the above-mentioned dicing die bond film 20 is not particularly limited, but it can be manufactured by a conventionally known method. For example, for the above-mentioned dicing die bond film 20, first, a wafer processing adhesive tape (dicing tape) 10 and a die bond film 20 are separately prepared. Next, the adhesive layer 2 of the wafer processing adhesive tape (dicing tape) 10 and the release liner of the die bond film (adhesive layer) 3 are peeled off respectively, and the adhesive layer 2 of the wafer processing adhesive tape (dicing tape) 10 and the die bond film (adhesive layer) 3 are bonded together by pressure bonding with a pressure bonding roll such as a hot roll laminator.

[0158] The bonding temperature is not particularly limited, and for example, it is preferably in the range of 10°C or higher and 100°C or lower. The bonding pressure (linear pressure) is preferably in the range of, for example, 0.1 kgf / cm or higher and 100 kgf / cm or lower. In the present invention, the dicing die bond film 20 may also be referred to as a laminate in which a release liner is provided on the adhesive layer 2 and the die bond film (adhesive layer) 3. In the dicing die bond film 20, the release liner provided on the adhesive layer 2 and the die bond film (adhesive layer) 3 may be peeled off when the dicing die bond film 20 is supplied to the workpiece.

[0159] The above dicing die bond film 20 may be in a form wound in a roll shape or a form in which wide sheets are laminated. Further, it may be in a sheet-like or tape-like laminated form formed by cutting the wafer processing adhesive tape 10 and the die bond film 3 in these forms into a predetermined size in advance.

[0160] For example, as disclosed in Japanese Patent Application Laid-Open No. 2011-159929, it can also be manufactured in a film roll shape in which a plurality of adhesive layers (die bond films 3) and adhesive films (dicing tapes 10) precut into the shape of a wafer constituting a semiconductor element are formed in an island shape on a release substrate (release liner). In this case, the dicing tape 10 is formed in a circular shape with a larger diameter than the die bond film (adhesive layer) 3, and the die bond film (adhesive layer) 3 is formed in a circular shape with a larger diameter than the semiconductor wafer 30. When such a precut process is performed in the form of a film roll, the excess dicing tape 10 is peeled off and removed.

[0161] (Method for manufacturing a semiconductor chip) FIG. 7 is a flowchart for explaining a method of manufacturing a semiconductor chip using a dicing die bond film 20 in which a die bond film (adhesive layer) 3 is laminated on an adhesive layer 2 of an adhesive tape for wafer processing (dicing tape) 10 according to the present embodiment. FIG. 8 is a schematic view showing a state in which a ring frame (wafer ring) 40 is provided at an outer edge portion (adhesive layer 2 exposed portion) of the adhesive tape for wafer processing (dicing tape) 10 of the dicing die bond film 20, and a semiconductor wafer processed to be singulated is attached on the die bond film (adhesive layer) 3 at the center portion. FIGS. 9(a) to 9(f) are cross-sectional views showing an example of a grinding process of a semiconductor wafer in which a plurality of modified regions are formed by laser beam irradiation and a bonding process of the semiconductor wafer to the dicing die bond film. FIGS. 10(a) to 10(f) are cross-sectional views showing an example of a method of manufacturing a semiconductor chip using a thin film semiconductor wafer having a plurality of modified regions to which the dicing die bond film is bonded.

[0162] (Method of manufacturing a semiconductor chip using the dicing die bond film 20) The method of manufacturing a semiconductor chip using the dicing die bond film 20 is not particularly limited and may be based on any of the methods described above. Here, a manufacturing method by SDBG (Stealth Dicing Before Griding) will be described as an example.

[0163] First, as shown in FIG. 9(a), for example, a semiconductor wafer W having a plurality of integrated circuits (not shown) mounted on a first surface Wa of a semiconductor wafer W mainly composed of silicon is prepared (step S201: preparation step in FIG. 7). Then, a back grind tape T having an adhesive surface Ta is bonded to the first surface Wa side of the semiconductor wafer W.

[0164] Next, as shown in FIG. 9(b), with the semiconductor wafer W held by the back grind tape T, laser light focused at a condensing point is irradiated onto the semiconductor wafer W from the side opposite to the back grind tape T, that is, from the second surface Wb side of the semiconductor wafer W, along the lattice-like planned division lines X thereof, and a modified region 30b is formed in the semiconductor wafer W due to ablation by multi-photon absorption (step S202 in FIG. 7: modified region formation step). The modified region 30b is a weakening region for cutting and separating the semiconductor wafer W into semiconductor chip units by a cool expand process. Regarding the method of forming the modified region 30b along the planned division lines by laser light irradiation in the semiconductor wafer W, for example, methods disclosed in Japanese Patent No. 3408805, Japanese Patent Application Laid-Open No. 2002-192370, Japanese Patent Application Laid-Open No. 2003-338567, etc. can be referred to.

[0165] Next, as shown in FIG. 9(c), with the semiconductor wafer W held by the back grind tape T, the semiconductor wafer W is thinned by grinding from the second surface Wb until it reaches a predetermined thickness. Here, the thickness of the semiconductor wafer 30 is preferably adjusted to 100 μm or less, more preferably 10 μm or more and 50 μm or less, from the viewpoint of thinning the semiconductor device. Thereby, a thin-film semiconductor wafer 30 having a modified region 30b therein that facilitates individualization into a plurality of semiconductor chips 30a is obtained by cool expansion in a subsequent process (step S203 in FIG. 7: grinding and thinning step). In this grinding and thinning process, depending on differences such as the final thickness of the semiconductor wafer 30 after grinding, the number of scanning times (input power) of laser light irradiation, and the physical properties of the back grind tape T, when a grinding load of the grinding wheel is applied, the semiconductor wafer 30 may crack in the vertical direction starting from the modified region 30b and be cut into individual semiconductor chips 30a at this stage, or may not crack and not be cut.

[0166] Next, as shown in FIGS. 9(d) and 9(e), a semiconductor wafer 30 of a thin film having a plurality of modified regions 30b held by a back grind tape T therein (when the semiconductor wafer 30 has already been singulated into semiconductor chips 30a, a plurality of semiconductor chips 30a) is bonded to a bond film 3 of a dicing die bond film 20 prepared separately (step S204 in FIG. 7: bonding step). In this step, after peeling off the release liner from the adhesive layer 2 and the bond film (adhesive layer) 3 of the circularly cut dicing die bond film 20, as shown in FIG. 8, a ring frame (wafer ring) 40 is attached to the outer edge portion (adhesive layer 2 exposed portion) of the dicing tape 10 of the dicing die bond film 20, and a semiconductor wafer 30 of a thin film that has been processed to be singulatable (when the semiconductor wafer 30 has already been singulated into semiconductor chips 30a, a plurality of semiconductor chips 30a) is attached onto the bond film (adhesive layer) 3 laminated on the upper central portion of the adhesive layer 2 of the dicing tape 10.

[0167] Thereafter, as shown in FIG. 9(f), the back grind tape T is peeled off from the semiconductor wafer 30 of the thin film (when the semiconductor wafer 30 has already been singulated into semiconductor chips 30a, a plurality of semiconductor chips 30a). The bonding is performed while pressing with a pressing means such as a pressure roll. The bonding temperature is not particularly limited, and for example, it is preferably in the range of 20°C or higher and 130°C or lower, and more preferably in the range of 40°C or higher and 100°C or lower from the viewpoint of reducing the warp of the semiconductor wafer 30. The bonding pressure is not particularly limited, and is preferably in the range of 0.1 MPa or higher and 10.0 MPa or lower. Since the adhesive tape for wafer processing (dicing tape) 10 of the present invention has a certain heat resistance, there is no particular problem in its handling even when the bonding temperature is high.

[0168] Subsequently, after the ring frame 40 is attached onto the adhesive layer 2 of the wafer processing adhesive tape (dicing tape) 10 in the dicing die bond film 20, as shown in Fig. 10(a), the dicing die bond film 20 with the thin film semiconductor wafer 30 (when the semiconductor wafer 30 has already been scribed into semiconductor chips 30a, it is a plurality of semiconductor chips 30a) that has been processed to be singulatable is fixed to the holder 41 of the expand device. As shown in Fig. 10(b), the thin film semiconductor wafer 30 has a plurality of modified regions 30b formed therein along the dicing planned line X so as to be singulatable into a plurality of semiconductor chips 30a.

[0169] Next, a first expand process, i.e., a cool expand process, is performed under relatively low temperature conditions (for example, -30°C or higher and 0°C or lower), as shown in Fig. 10(c). The semiconductor wafer 30 is singulated into a plurality of semiconductor chips 30a, and the die bond film (adhesive layer) 3 of the dicing die bond film 20 is scribed into small pieces of die bond film (adhesive layer) 3a corresponding to the size of the semiconductor chip 30a, obtaining semiconductor chips 30a with die bond film 3a (step S205 in Fig. 7: cool expand process). In this process, a hollow cylindrical pushing member (not shown) provided in the expand device abuts against the wafer processing adhesive tape (dicing tape) 10 below the dicing die bond film 20 and rises, and the wafer processing adhesive tape (dicing tape) 10 of the dicing die bond film 20 to which the singulatable processed semiconductor wafer 30 is bonded is expanded so as to be stretched in a two-dimensional direction including the radial direction and the circumferential direction of the semiconductor wafer 30.

[0170] The internal stress generated by the all-directional tension of the adhesive tape for wafer processing (dicing tape) 10 due to cool expansion is transmitted as external stress to the semiconductor wafer 30 processed to be singulatable and the die bond film 3 attached to the semiconductor wafer 30. Due to this external stress, the semiconductor wafer 30 cracks vertically starting from a plurality of lattice-shaped modified regions 30b formed therein, is severed into individual semiconductor chips 30a, and the die bond film 3 embrittled at low temperature is also severed into small pieces of die bond film 3a of the same size as the semiconductor chips 30a. When the semiconductor wafer 30 has already been severed into individual semiconductor chips 30a in the grinding and thinning process, only the die bond film 3 embrittled at low temperature in close contact with the semiconductor chips 30a is severed into small pieces of die bond film 3a corresponding to the size of the semiconductor chips 30a by cool expansion, and semiconductor chips 30a with die bond film 3a are obtained.

[0171] The temperature conditions in the above cool expansion process are, for example, -30°C or higher and 0°C or lower, preferably in the range of -20°C or higher and -5°C or lower, more preferably in the range of -15°C or higher and -5°C or lower, and particularly preferably -15°C. The expansion speed (the speed at which the hollow cylindrical lifting member rises) in the above cool expansion process is preferably in the range of 0.1 mm / second or higher and 1000 mm / second or lower, more preferably in the range of 10 mm / second or higher and 300 mm / second or lower. Also, the expansion amount (the lifting height of the hollow cylindrical lifting member) in the above cool expansion process is preferably in the range of 3 mm or higher and 16 mm or lower.

[0172] Here, the adhesive tape for wafer processing (dicing tape) 10 of the present invention has a structure in which a resin layer containing an ionomer resin obtained by crosslinking an ethylene-unsaturated carboxylic acid copolymer containing a structural unit derived from an unsaturated carboxylic acid at a specific content ratio with zinc ions at a specific concentration is laminated on the base film 1. Therefore, in the continuous layer of the ethylene-unsaturated carboxylic acid copolymer, the development of ion aggregates (clusters) becomes sufficient and appropriate. Due to the crosslinking effect, even when the base film 1 is expanded, the ion aggregates (clusters) are less likely to be destroyed, and the number of molecular chain tensions between the ion aggregates increases as the expansion progresses. As a result, the internal stress generated by the tension in all directions of the dicing tape 10 due to cool expansion is efficiently transmitted as an external stress to the die bond film 3 attached to the semiconductor wafer 30, for example. As a result, the die bond film 3 is cut into small pieces of the die bond film 3a corresponding to the size of the semiconductor chip 30a with good yield, and the semiconductor chip 30a with the die bond film 3a is obtained with good yield. And even if a wire embedding type die bond film having a large thickness and high fluidity (low melt viscosity at high temperature) is used as the die bond film 3, it can be cut with good yield.

[0173] After the above cool expansion process, the hollow cylindrical pushing member of the expansion device is lowered, and the expanded state of the adhesive tape for wafer processing (dicing tape) 10 is released.

[0174] Next, a second expansion process, i.e., a normal-temperature expansion process, is performed under relatively high-temperature conditions (e.g., 10°C or higher and 30°C or lower). As shown in FIG. 10(d), the distance (kerf width) between the semiconductor chips 30a with the die bond film (adhesive layer) 3a is widened. In this process, a cylindrical table (not shown) provided in the expansion apparatus abuts against the wafer processing adhesive tape (dicing tape) 10 below the dicing die bond film 20 and rises, and the wafer processing adhesive tape (dicing tape) 10 of the dicing die bond film 20 is expanded (step S206 in FIG. 7: normal-temperature expansion process). By sufficiently securing the distance (kerf width) between the semiconductor chips 30a with the die bond film (adhesive layer) 3a in the normal-temperature expansion process, the recognition performance of the semiconductor chips 30a by a CCD camera or the like is improved, and re-adhesion between the semiconductor chips 30a with the die bond film (adhesive layer) 3a caused by contact between adjacent semiconductor chips 30a during pickup can be prevented. As a result, in the pickup process described later, the pickup performance of the semiconductor chips 30a with the die bond film (adhesive layer) 3a is improved.

[0175] The temperature condition in the above normal-temperature expansion process is, for example, 10°C or higher, preferably in the range of 15°C or higher and 30°C or lower. The expansion speed (the speed at which the cylindrical table rises) in the normal-temperature expansion process is, for example, in the range of 0.1 mm / second or higher and 50 mm / second or lower, preferably in the range of 0.3 mm / second or higher and 30 mm / second or lower. Also, the expansion amount in the normal-temperature expansion process is, for example, in the range of 3 mm or higher and 20 mm or lower.

[0176] After the wafer dicing tape 10 is expanded at room temperature by the rising of the table, the table vacuum-adsorbs the wafer dicing tape 10. Then, while maintaining the adsorption by the table, the table is lowered with the workpiece, and the expanded state of the wafer dicing tape 10 is released. In order to suppress the narrowing of the kerf width of the semiconductor chip 30a with the die bond film (adhesive layer) 3a on the wafer dicing tape 10 after the release of the expanded state, in the state where the wafer dicing tape 10 is vacuum-adsorbed to the table, the circumferential portion outside the semiconductor chip 30a holding region in the wafer dicing tape 10 is heated and shrunk (heat shrink) by hot air blowing, and it is preferable to maintain a tension state by eliminating the slack of the wafer dicing tape 10 generated by expansion. After the above heat shrinkage, the vacuum adsorption state by the table is released.

[0177] The temperature of the hot air may be adjusted according to the physical properties of the base film 1, the distance between the hot air outlet and the dicing tape, the air volume, etc. For example, a range of 200°C or more and 250°C or less is preferable. Also, the distance between the hot air outlet and the wafer dicing tape 10 is preferably in the range of, for example, 15 mm or more and 25 mm or less. Also, the air volume is preferably in the range of, for example, 35 L / min or more and 45 L / min or less. When performing the heat shrink process, while rotating the stage of the expansion device at a rotation speed in the range of, for example, 3° / second or more and 10° / second or less, hot air blowing is performed along the circumferential portion outside the semiconductor chip 30a holding region of the wafer dicing tape 10. By such hot air blowing, the temperature of the surface of the wafer dicing tape 10 is adjusted to around 80°C, for example.

[0178] The adhesive tape (dicing tape) 10 for wafer processing of the present invention uses, as its base film 1, a laminated resin layer containing an ionomer resin in which an ethylene-unsaturated carboxylic acid copolymer containing a structural unit derived from an unsaturated carboxylic acid at a specific content ratio is crosslinked with zinc ions at a specific concentration and has an appropriate Vicat softening temperature. Therefore, in the continuous layer of the ethylene-unsaturated carboxylic acid copolymer, the development of ion aggregates (clusters) formed by the aggregation of ionic bonds between carboxylate ions of acid groups derived from unsaturated carboxylic acids and zinc ions is sufficient and appropriate. Due to its crosslinking effect, even when the base film 1 is heated, the ion aggregates (clusters) are not completely destroyed but are moderately maintained. Therefore, in the heat shrinkage process after expansion, the entropy elasticity acts strongly, and the stretched and oriented molecules tend to return to their original state. That is, the restoring force during heating against the strain after stretching of the base film 1 becomes sufficient, and in the heat shrinkage process of the adhesive tape 10 for wafer processing, no heat wrinkles or the like occur, and the circumferential portion of the dicing tape 10 can be heated and shrunk without problems to eliminate slack. As a result, a sufficient kerf width is ensured between individual semiconductor chips, and good pick-up properties can be obtained in the pick-up process described later.

[0179] Subsequently, the adhesive tape for wafer processing (dicing tape) 10 is irradiated with active energy rays from the base film 1 side to cure and shrink the adhesive layer 2, thereby reducing the adhesive force of the adhesive layer 2 to the dicing film 3a (step S207 in FIG. 7: active energy ray irradiation step). Here, examples of the active energy rays used for the post-irradiation include ultraviolet rays, visible light rays, infrared rays, electron beams, β rays, γ rays, and the like. Among these active energy rays, ultraviolet rays (UV) and electron beams (EB) are preferable, and ultraviolet rays (UV) are particularly preferably used. The light source for irradiating the ultraviolet rays (UV) is not particularly limited, and for example, a black light, an ultraviolet fluorescent lamp, a low-pressure mercury lamp, a medium-pressure mercury lamp, a high-pressure mercury lamp, an ultra-high-pressure mercury lamp, a carbon arc lamp, a metal halide lamp, a xenon lamp, or the like can be used. Further, an ArF excimer laser, a KrF excimer laser, an excimer lamp, synchrotron radiation light, or the like can also be used. The irradiation light amount of the ultraviolet rays (UV) is not particularly limited, and for example, it is preferably in the range of 100 mJ / cm 2 or more and 2,000 mJ / cm 2 or less, and more preferably in the range of 300 mJ / cm 2 or more and 1,000 mJ / cm 2 or less.

[0180] Here, in the active energy ray curable adhesive composition constituting the adhesive layer 2 of the adhesive tape for wafer processing (dicing tape) 10 of the present invention, the concentration of the active energy ray reactive carbon-carbon double bond is controlled, for example, in the range of 0.85 mmol or more and 1.60 mmol or less per 1 g of the active energy ray curable adhesive composition. Therefore, after ultraviolet ray (UV) irradiation, the adhesive layer 2 has an increased crosslinking density due to the three-dimensional crosslinking reaction of the carbon-carbon double bond, that is, the storage elastic modulus greatly increases, the glass transition temperature also increases, and the volume shrinkage also increases. As a result, the adhesive force to the dicing film 3a can be sufficiently reduced. As a result, in the pickup process described later, the pickup property of the semiconductor chip 30a with the dicing film (adhesive layer) 3a is improved.

[0181] Subsequently, a so-called pick-up is performed to peel off each semiconductor chip 30a with a die bond film (adhesive layer) 3a that has been severed and fragmented by the above-described expansion process from the adhesive layer 2 after ultraviolet (UV) irradiation of the wafer processing adhesive tape (dicing tape) 10 (step S208 in FIG. 7: peeling (pick-up) process).

[0182] As a method for the above pick-up, for example, as shown in FIG. 10(e), the semiconductor chip 30a with a die bond film (adhesive layer) 3a is pushed up by a push-up pin (needle) 60 against the second surface of the base film 1 of the wafer processing adhesive tape (dicing tape) 10, and as shown in FIG. 10(f), the pushed-up semiconductor chip 30a with a die bond film (adhesive layer) 3a is sucked by a suction collet 50 of a pick-up device (not shown) to be peeled off from the adhesive layer 2 of the wafer processing adhesive tape (dicing tape) 10. By this, a semiconductor chip 30a with a die bond film (adhesive layer) 3a is obtained.

[0183] The pick-up conditions are not particularly limited as long as they are within an acceptable range in practical use. Usually, the push-up speed of the push-up pin (needle) 60 is often set within the range of 1 mm / second or more and 100 mm / second or less. However, when the thickness of the semiconductor chip 30a (thickness of the semiconductor wafer) is as thin as 100 μm or less, from the viewpoint of suppressing damage to the thin-film semiconductor chip 30a, it is preferably set within the range of 1 mm / second or more and 20 mm / second or less. From the viewpoint of considering productivity, it is more preferably set within the range of 5 mm / second or more and 20 mm / second or less.

[0184] In addition, the push-up height of the push-up pins that enables the semiconductor chip 30a to be picked up without being damaged can be preferably set within a range of 100 μm or more and 600 μm or less, for example, from the same viewpoint as described above. From the viewpoint of stress reduction for the semiconductor thin film chip, it can be more preferably set within a range of 100 μm or more and 450 μm or less. From the viewpoint considering productivity, it is particularly preferable that it can be set within a range of 100 μm or more and 350 μm or less. It can be said that the wafer processing adhesive tape (dicing tape) capable of making such a push-up height smaller is excellent in pick-up property.

[0185] As described above, the base film 1 composed of a laminated resin layer containing an ionomer resin in which an ethylene-unsaturated carboxylic acid copolymer containing a structural unit derived from an unsaturated carboxylic acid is crosslinked with zinc ions at a specific concentration and has an appropriate Vicat softening temperature, and the adhesive layer 2 composed of an active energy ray curable adhesive composition. The wafer processing adhesive tape (dicing tape) 10 of the present invention is used in the semiconductor manufacturing process in the form of a dicing die bond film 20 in which a die bond film (adhesive layer) 3 is peelably adhered and laminated on the adhesive layer 2 of the wafer processing adhesive tape (dicing tape) 10. For example, even when applying a die bond film with high fluidity and a thick thickness, such as a wire embedding type die bond film, the semiconductor wafer 30 with the die bond film 3 can be favorably cut by cool expansion, and a sufficient kerf width can be ensured by normal temperature expansion and heat shrinkage. In the die bond film 3a after cutting, the semiconductor chips 30a with the cut individual die bond films 3a can be favorably picked up from the adhesive layer 2 of the wafer processing adhesive tape (dicing tape) 10.

[0186] Note that the manufacturing method described with reference to FIGS. 10(a) to 10(f) is an example (SDBG) of the manufacturing method of the semiconductor chip 30a using the dicing die bond film 20, and the method of using the wafer processing adhesive tape (dicing tape) 10 in the form of the dicing die bond film 20 is not limited to the above method. For example, instead of the method of forming the modified region 30b along the planned division line by irradiating the semiconductor wafer W with a laser beam as described with reference to FIG. 9(b), a method of forming a division groove having a predetermined depth on the first surface Wa side of the semiconductor wafer W with a rotating blade may be adopted. In this case, although not shown, after the back grind tape T2 having the adhesive surface T2a is bonded to the second surface Wb side of the semiconductor wafer W, in a state where the semiconductor wafer W is held by the back grind tape T2, a division groove having a predetermined depth is formed on the first surface Wa side of the semiconductor wafer W using a rotating blade of a dicing apparatus or the like. Next, the back grind tape T having the adhesive surface Ta is bonded to the first surface Wa side of the semiconductor wafer W, and the back grind tape T2 is peeled off from the semiconductor wafer W, resulting in the state of FIG. 9(b). In the grinding and thinning process shown in FIG. 9(c), a method of grinding the semiconductor wafer W until the division groove itself is exposed on the second surface Wb side may be adopted, or the semiconductor wafer W may be ground until before reaching the division groove from the second surface Wb side, and then, a method of forming a crack between the division groove and the second surface by the action of the grinding load pressure from the grinding wheel to the semiconductor wafer W to form divided bodies (a plurality of semiconductor chips 30a) of the semiconductor wafer W may be adopted. Depending on the method adopted, the depth of the formed division groove from the first surface Wa is appropriately determined.

[0187] Thus , dam The dicing die bond film 20 can be used without being limited to the above method as long as it can be attached to the semiconductor wafer 30 during dicing.

[0188] Among them, the adhesive tape for wafer processing (dicing tape) 10 of the present invention is particularly suitable as a dicing tape for use as a dicing die bond film by being integrated with a wire-embedded die bond film in a manufacturing method for obtaining thin film semiconductor chips such as DBG, stealth dicing, and SDBG. Of course, it is also possible to use it in integration with a general-purpose die bond film.

[0189] (Method of manufacturing a semiconductor device) A semiconductor device in which a semiconductor chip manufactured using a dicing die bond film 20 in which the adhesive tape for wafer processing (dicing tape) 10 to which the present embodiment is applied and the die bond film 3 are integrated is mounted will be specifically described below.

[0190] A semiconductor device (semiconductor package) can be obtained, for example, by thermocompression bonding and adhering a semiconductor chip 30a with the above-described die bond film (adhesive layer) 3a to a semiconductor chip mounting support member or a semiconductor chip, and then passing through processes such as a wire bonding process and a sealing process using a sealing material.

[0191] FIG. 11 is a schematic cross-sectional view of one aspect of a semiconductor device having a stacked structure on which a semiconductor chip manufactured using a dicing die bond film 20 in which the adhesive tape for wafer processing (dicing tape) 10 to which the present embodiment is applied and a wire-embedded die bond film 3 are integrated is mounted. The semiconductor device 70 shown in FIG. 11 includes a semiconductor chip mounting support substrate 4, cured die bond films (adhesive layers) 3a1 and 3a2, a first-stage semiconductor chip 30a1, a second-stage semiconductor chip 30a2, and a sealing material 8. The semiconductor chip mounting support substrate 4, the cured die bond film 3a1, and the semiconductor chip 30a1 constitute a support member 9 for the semiconductor chip 30a2.

[0192] On one surface of the support substrate 4 for mounting semiconductor chips, a plurality of external connection terminals 5 are arranged. On the other surface of the support substrate 4 for mounting semiconductor chips, a plurality of terminals 6 are arranged. The support substrate 4 for mounting semiconductor chips has wires 7 for electrically connecting connection terminals (not shown) of the semiconductor chips 30a1 and 30a2 and the external connection terminals 5. The semiconductor chip 30a1 is adhered to the support substrate 4 for mounting semiconductor chips by a cured die bond film 3a1 in such a manner as to embed irregularities derived from the external connection terminals 5. The semiconductor chip 30a2 is adhered to the semiconductor chip 30a1 by a cured die bond film 3a2. The semiconductor chip 30a1, the semiconductor chip 30a2, and the wires 7 are encapsulated by an encapsulant 8. Thus, the wire-embedded die bond film 3a is suitably used for a semiconductor device having a stacked structure in which a plurality of semiconductor chips 30a are stacked.

[0193] Further, FIG. 12 is a schematic cross-sectional view of one aspect of another semiconductor device on which a semiconductor chip manufactured using a dicing die bond film 20 in which a wafer processing adhesive tape (dicing tape) 10 to which the present embodiment is applied and a general-purpose die bond film 3 are integrated is mounted. The semiconductor device 80 shown in FIG. 12 includes a support substrate 4 for mounting semiconductor chips, a cured die bond film 3a, a semiconductor chip 30a, and an encapsulant 8. The support substrate 4 for mounting semiconductor chips is a support member for the semiconductor chip 30a and has wires 7 for electrically connecting connection terminals (not shown) of the semiconductor chip 30a and external connection terminals (not shown) arranged on the main surface of the support substrate 4 for mounting semiconductor chips. The semiconductor chip 30a is adhered to the support substrate 4 for mounting semiconductor chips by a cured die bond film 3a. The semiconductor chip 30a and the wires 7 are encapsulated by an encapsulant 8. Body chi The semiconductor chip 30a is adhered to the support substrate 4 for mounting semiconductor chips by a cured die bond film 3a. The semiconductor chip 30a and the wires 7 are encapsulated by an encapsulant 8.

Example

[0194] The present invention will be described more specifically by the following examples, but the present invention is not limited thereto.

[0195] 1. Preparation of the base film 1 The following resins were respectively prepared as materials for producing the base films 1(a) to 1(z). As the zinc (Zn2+) ion source of the ionomer resin, a mixture having a mass ratio of zinc oxide / zinc stearate = 99 / 1 was used.

[0196] (Resin composed of an ionomer of an ethylene / unsaturated carboxylic acid copolymer) (1) Resin (IO-1) Zinc ionomer resin of a terpolymer having a mass ratio of ethylene / methacrylic acid / isobutyl acrylate = 80 / 10 / 10, zinc (Zn2+) ion concentration per 1 g of the copolymer: 0.38 mmol, Vicat softening temperature: 56 °C

[0197] (2) Resin (IO-2) Zinc ionomer resin of a terpolymer having a mass ratio of ethylene / methacrylic acid / isobutyl acrylate = 80 / 10 / 10, zinc (Zn2+) ion concentration per 1 g of the copolymer: 0.41 mmol, Vicat softening temperature: 57 °C

[0198] (3) Resin (IO-3) Zinc ionomer resin of a terpolymer having a mass ratio of ethylene / methacrylic acid / isobutyl acrylate = 80 / 10 / 10, zinc (Zn2+) ion concentration per 1 g of the copolymer: 0.46 mmol, Vicat softening temperature: 57 °C

[0199] (4) Resin (IO-4) Zinc ionomer resin of a terpolymer having a mass ratio of ethylene / methacrylic acid / isobutyl acrylate = 80 / 10 / 10, zinc (Zn2+) ion concentration per 1 g of the copolymer: 0.52 mmol, Vicat softening temperature: 57 °C

[0200] (5) Resin (IO-5) Zinc ionomer resin of a terpolymer consisting of ethylene / methacrylic acid / isobutyl acrylate = 80 / 10 / 10 by mass ratio, zinc (Zn2+) ion concentration per 1 g of copolymer: 0.55 mmol, Vicat softening temperature: 57 °C

[0201] (6) Resin (IO-6) Zinc ionomer resin of a terpolymer consisting of ethylene / methacrylic acid / isobutyl acrylate = 80 / 8 / 12 by mass ratio, zinc (Zn2+) ion concentration per 1 g of copolymer: 0.41 mmol, Vicat softening temperature: 55 °C

[0202] (7) Resin (IO-7) Zinc ionomer resin of a terpolymer consisting of ethylene / methacrylic acid / isobutyl acrylate = 80 / 12 / 8 by mass ratio, zinc (Zn2+) ion concentration per 1 g of copolymer: 0.41 mmol, Vicat softening temperature: 58 °C

[0203] (8) Resin (IO-8) Zinc ionomer resin of a terpolymer consisting of ethylene / methacrylic acid / isobutyl acrylate = 80 / 15 / 5 by mass ratio, zinc (Zn2+) ion concentration per 1 g of copolymer: 0.41 mmol, Vicat softening temperature: 56 °C

[0204] (9) Resin (IO-9) Zinc ionomer resin of a terpolymer consisting of ethylene / methacrylic acid / isobutyl acrylate = 91.6 / 6.9 / 10 by mass ratio, zinc (Zn2+) ion concentration per 1 g of copolymer: 0.38 mmol, Vicat softening temperature: 64 °C

[0205] (10) Resin (IO-10) Zinc ionomer resin of a terpolymer consisting of ethylene / methacrylic acid / isobutyl acrylate = 77.1 / 6.9 / 16 by mass ratio, zinc (Zn2+) ion concentration per 1 g of copolymer: 0.38 mmol, Vicat softening temperature: 50 °C

[0206] (11) Resin (IO-12) Zinc ionomer resin of a terpolymer consisting of ethylene / methacrylic acid / isobutyl acrylate with a mass ratio of 88.1 / 6.9 / 5, zinc (Zn2+) ion concentration per 1 g of the copolymer: 0.38 mmol, Vicat softening temperature: 74 °C

[0207] (12) Resin (IO-13) Zinc ionomer resin of a terpolymer consisting of ethylene / methacrylic acid / isobutyl acrylate with a mass ratio of 80.5 / 18 / 1.5, zinc (Zn2+) ion concentration per 1 g of the copolymer: 0.41 mmol, Vicat softening temperature: 51 °C

[0208] (13) Resin (IO-14) Zinc ionomer resin of a terpolymer consisting of ethylene / methacrylic acid / isobutyl acrylate with a mass ratio of 80.5 / 18 / 1.5, zinc (Zn2+) ion concentration per 1 g of the copolymer: 0.60 mmol, Vicat softening temperature: 51 °C

[0209] (14) Resin (IO-15) Zinc ionomer resin of a binary copolymer consisting of ethylene / methacrylic acid with a mass ratio of 82 / 18, zinc (Zn2+) ion concentration per 1 g of the copolymer: 0.38 mmol, Vicat softening temperature: 54 °C

[0210] (15) Resin (IO-16) Zinc ionomer resin of a terpolymer consisting of ethylene / methacrylic acid / isobutyl acrylate with a mass ratio of 80 / 10 / 10, zinc (Zn2+) ion concentration per 1 g of the copolymer: 0.35 mmol, Vicat softening temperature: 56 °C

[0211] (16) Resin (IO-17) Zinc ionomer resin of a terpolymer consisting of ethylene / methacrylic acid / isobutyl acrylate with a mass ratio of 85 / 5 / 10, zinc (Zn2+) ion concentration per 1 g of the copolymer: 0.29 mmol, Vicat softening temperature: 70 °C

[0212] (17) Resin (IO-18) Zinc ionomer resin of a terpolymer consisting of ethylene / methacrylic acid / isobutyl acrylate = 78 / 19 / 3 by mass ratio, zinc (Zn2+) ion concentration per 1 g of the copolymer: 0.35 mmol, Vicat softening temperature: 44 °C

[0213] (18) Resin (IO-19) Zinc ionomer resin of a terpolymer consisting of ethylene / methacrylic acid / isobutyl acrylate = 93 / 4 / 3 by mass ratio, zinc (Zn2+) ion concentration per 1 g of the copolymer: 0.22 mmol, Vicat softening temperature: 87 °C

[0214] (19) Resin (IO-20) Zinc ionomer resin of a terpolymer consisting of ethylene / methacrylic acid / isobutyl acrylate = 75 / 15 / 10 by mass ratio, zinc (Zn2+) ion concentration per 1 g of the copolymer: 0.83 mmol, Vicat softening temperature: 57 °C

[0215] (Resin composed of an ionomer of an ethylene / unsaturated carboxylic acid copolymer and other resins) (20) Mixed resin (IO-2 / PA) A mixed resin obtained by dry blending a zinc ionomer resin (IO-2) of a terpolymer consisting of ethylene / methacrylic acid / isobutyl acrylate = 80 / 10 / 10 by mass ratio and polyamide resin "Amilan (registered trademark) CM1017" (PA) manufactured by Toray Industries, Inc. in a mass ratio of 90:10, Vicat softening temperature of the mixed resin melt-kneaded at a single-screw extruder die temperature of 230 °C: 61 °C

[0216] (21) Mixed resin (IO-2 / TPO-1) A mixed resin obtained by dry blending a zinc ionomer resin (IO-2) of a terpolymer consisting of ethylene / methacrylic acid / isobutyl acrylate = 80 / 10 / 10 by mass ratio and polypropylene-based elastomer "Zealus (registered trademark) 5053" (TPO-1) manufactured by Mitsubishi Chemical Corporation in a mass ratio of 80:20, Vicat softening temperature of the mixed resin melt-kneaded at a single-screw extruder die temperature of 230 °C: 55 °C

[0217] (Ethylene-unsaturated carboxylic acid copolymer resin) (22) Resin (EMAA) A binary copolymer consisting of ethylene / methacrylic acid with a mass ratio of 96 / 4, Vicat softening temperature: 92 °C

[0218] (Olefin thermoplastic elastomer) (23) Resin (TPO-1) Polypropylene-based elastomer "Zeelas (registered trademark) 5053" manufactured by Mitsubishi Chemical Corporation, propylene / ethylene = 79 / 21 mass ratio, Vicat softening temperature: 50 °C

[0219] (24) Resin (TPO-2) Multi-stage polymerization propylene / ethylene copolymer [Reactor TPO] "Catalloy (registered trademark)" manufactured by LyondellBasell, Vicat softening temperature: 59 °C

[0220] <Base film 1(a)> Ionomer resin (IO-1) was put into each extruder of a 1-kind (same resin) 3-layer T-die film forming machine and formed under the condition of a processing temperature of 240 °C to produce a base film 1(a) with a 3-layer structure of the same resin and a thickness of 90 μm. In addition, matte processing was performed on the side of the third resin layer (the side opposite to the surface in contact with the second resin layer). The thickness of each resin layer was set as the first resin layer (the surface side in contact with the adhesive layer 2) / the second resin layer / the third resin layer = 30 μm / 30 μm / 30 μm. The content ratio of the specific ionomer resin in each resin layer was 100% by mass. Also, the total thickness of the resin layers (the first resin layer, the second resin layer, and the third resin layer) containing the specific ionomer resin at a content ratio of 80% by mass or more was 100% of the total thickness of the base film 1(a).

[0221] <Base films 1(b) to 1(j), 1(l) to 1(n)> The substrate films 1(b) to 1(j), 1(l) to 1(n) were each produced in the same manner as the substrate film 1(a), except that the ionomer resin (IO-1) was changed to ionomer resins (IO-2) to (IO-10), (IO-12) to (IO-14), respectively. The content ratio of the specific ionomer resin in each resin layer of the substrate films 1(b) to 1(j), 1(l) to 1(n) is 100% by mass. Also, the total thickness of the resin layers (the first resin layer, the second resin layer, and the third resin layer) containing the specific ionomer resin at a content ratio of 80% by mass or more is 100% of the total thickness of the substrate film 1 in each case.

[0222] <Substrate film 1(o)> Ionomer resin (IO-15) was prepared as the resin composition for the first resin layer and the third resin layer, and ionomer resin (IO-1) was prepared as the resin composition for the second resin layer. They were charged into the respective extruders of a two-component (resin) three-layer T-die film forming machine and molded under the condition of a processing temperature of 240°C to produce a substrate film 1(o) with a three-layer structure of two resins and a thickness of 90 μm. In addition, mat processing was performed on the side of the third resin layer (the side opposite to the surface in contact with the second resin layer). The thickness of each resin layer was set as follows: the first resin layer (the surface side in contact with the adhesive layer 2) / the second resin layer / the third resin layer = 20 μm / 50 μm / 20 μm. The content ratio of the specific ionomer resin in each resin layer is 100% by mass. Also, the total thickness of the resin layers (the first resin layer, the second resin layer, and the third resin layer) containing the specific ionomer resin at a content ratio of 80% by mass or more is 100% of the total thickness of the substrate film 1(o).

[0223] <Substrate film 1(p)> As the resin composition for the first resin layer, an ionomer resin (IO-2) was prepared. As the resin composition for the second resin layer, an ionomer resin (IO-3) was prepared. As the resin composition for the third resin layer, an ionomer resin (IO-4) was prepared. These were put into the respective extruders of a three-layer T-die film forming machine with three types (resins), and molded under the condition of a processing temperature of 240°C to produce a base film 1(p) with a three-layer structure of three types of resins and a thickness of 90 μm. Note that the third resin layer side (the side opposite to the surface in contact with the second resin layer) was subjected to a matting process. The thickness of each resin layer was set as follows: the first resin layer (the surface side in contact with the adhesive layer 2) / the second resin layer / the third resin layer = 30 μm / 30 μm / 30 μm. The content ratio of the specific ionomer resin in each resin layer was 100% by mass. Also, the total thickness of the resin layers (the first resin layer, the second resin layer, and the third resin layer) containing the specific ionomer resin at a content ratio of 80% by mass or more was 100% of the total thickness of the base film 1(p).

[0224] <Base film 1(q)> As the resin composition for the first resin layer and the second resin layer, an ionomer resin (IO-2) was prepared. As the resin composition for the third resin layer, a mixed resin of an ionomer resin and a polyamide resin (IO-2 / PA) was prepared. These were put into the respective extruders of a three-layer T-die film forming machine with two types (resins), and molded under the condition of a processing temperature of 240°C to produce a base film 1(q) with a three-layer structure of two types of resins and a thickness of 90 μm. Note that the third resin layer side (the side opposite to the surface in contact with the second resin layer) was subjected to a matting process. The thickness of each resin layer was set as follows: the first resin layer (the surface side in contact with the adhesive layer 2) / the second resin layer / the third resin layer = 30 μm / 30 μm / 30 μm. The content ratio of the specific ionomer resin in the first resin layer and the second resin layer was 100% by mass, and the content ratio of the specific ionomer resin in the third resin layer was 90% by mass. Also, the total thickness of the resin layers (the first resin layer, the second resin layer, and the third resin layer) containing the specific ionomer resin at a content ratio of 80% by mass or more was 100% of the total thickness of the base film 1(q).

[0225] <Base film 1(r)> As the resin composition of the first resin layer, an ionomer resin (IO-2) was prepared. As the resin composition for the second resin layer, a mixed resin of an ionomer resin and an olefin-based thermoplastic elastomer resin (IO-2 / TPO-1) was prepared. They were put into the respective extruders of a two-component (resin) two-layer T-die film forming machine and molded under the condition of a processing temperature of 240°C to produce a base film 1(r) with a two-layer structure of two resins and a thickness of 70 μm. Note that the second resin layer side (the side opposite to the surface in contact with the first resin layer) was subjected to a matting process. The thickness of each resin layer was set as follows: the first resin layer (the surface side in contact with the adhesive layer 2) / the second resin layer = 50 μm / 20 μm. The content ratio of the specific ionomer resin in the first resin layer was 100% by mass, and the content ratio of the specific ionomer resin in the second resin layer was 80% by mass. Also, the total thickness of the resin layers (the first resin layer and the second resin layer) containing the specific ionomer resin at a content ratio of 80% by mass or more was 100% of the total thickness of the base film 1(r).

[0226] <Base film 1(s)> As the resin composition for the first resin layer and the third resin layer, an ionomer resin (IO-2) was prepared. As the resin composition for the second resin layer, an olefin-based thermoplastic elastomer resin (TPO-1) was prepared. They were put into the respective extruders of a two-component (resin) three-layer T-die film forming machine and molded under the condition of a processing temperature of 240°C to produce a base film 1(s) with a three-layer structure of two resins and a thickness of 90 μm. Note that the third resin layer side (the side opposite to the surface in contact with the second resin layer) was subjected to a matting process. The thickness of each resin layer was set as follows: the first resin layer (the surface side in contact with the adhesive layer 2) / the second resin layer / the third resin layer = 40 μm / 10 μm / 40 μm. The content ratio of the specific ionomer resin in the first resin layer and the third resin layer was 100% by mass. Also, the total thickness of the resin layers (the first resin layer and the third resin layer) containing the specific ionomer resin at a content ratio of 80% by mass or more was 89% of the total thickness of the base film 1(s).

[0227] <Base film 1(t)> As the resin composition for the first resin layer and the second resin layer, an ionomer resin (IO-2) was prepared, and as the resin composition for the third resin layer, an olefin-based thermoplastic elastomer resin (TPO-2) was prepared. They were put into the respective extruders of a two-component (resin) three-layer T-die film forming machine and molded under the condition of a processing temperature of 240°C to produce a base film 1(t) with a three-layer structure of two resins and a thickness of 120 μm. Note that the surface on the third resin layer side (the side opposite to the surface in contact with the second resin layer) was subjected to matting. The thickness of each resin layer was set as the first resin layer (the surface side in contact with the adhesive layer 2) / the second resin layer / the third resin layer = 40 μm / 40 μm / 40 μm. The content ratio of the specific ionomer resin in the first resin layer and the second resin layer was 100% by mass. Further, the total thickness of the resin layers (the first resin layer and the second resin layer) containing the specific ionomer resin at a content ratio of 80% by mass or more was 67% of the total thickness of the base film 1(t).

[0228] <Base films 1(u) to 1(y)> Base films 1(u) to 1(y) were each produced in the same manner as base film 1(a), except that the ionomer resin (IO-1) was changed to ionomer resins (IO-16) to (IO-20) respectively. Note that for the base film 1(y) using the ionomer resin (IO-20), the melt flow rate (MFR) was small and stable film formation could not be achieved.

[0229] <Base film 1(z)> As the resin composition for the first resin layer, an ionomer resin (IO-16) was prepared, and as the resin composition for the second resin layer, an ethylene-unsaturated carboxylic acid copolymer resin (EMAA) was prepared. They were put into the respective extruders of a two-component (resin) two-layer T-die film forming machine and molded under the condition of a processing temperature of 240°C to produce a base film 1(z) with a two-layer structure of two resins and a thickness of 100 μm. The thickness of each resin layer was set as the first resin layer (the surface side in contact with the adhesive layer 2) / the second resin layer = 40 μm / 60 μm.

[0230] 2. Preparation of the solution of the adhesive composition As an adhesive composition for the adhesive layer 2 of the dicing tape 10, a solution of the following active energy ray-curable acrylic adhesive composition 2(a) was prepared.

[0231] (Solution of the active energy ray-curable acrylic adhesive composition 2(a)) As copolymer monomer components, 2-ethylhexyl acrylate (2-EHA), 2-hydroxyethyl acrylate (2-HEA), and methyl methacrylate (MMA) were prepared. These copolymer monomer components were mixed so as to have a copolymerization ratio of 2-EHA / 2-HEA / MMA = 78.5 parts by mass / 21.0 parts by mass / 0.5 parts by mass (= 425.94 mmol / 180.85 mmol / 5.81 mmol), and using ethyl acetate as a solvent and azobisisobutyronitrile (AIBN) as an initiator, a solution of a base polymer (acrylic ester copolymer) having a hydroxyl group was synthesized by solution radical polymerization. The Tg calculated from Fox's equation of the obtained base polymer was -60°C.

[0232] Next, with respect to 100 parts by mass of the solid content of this base polymer, as an active energy ray-reactive compound manufactured by Showa Denko K.K., 21.0 parts by mass (135.35 mmol: 74.8 mol% with respect to 2-HEA) of 2-isocyanatoethyl methacrylate (trade name: KARENZ MOI, molecular weight: 155.15, isocyanate group: 1 per molecule, double bond group: 1 per molecule) manufactured by Showa Denko K.K. was blended and reacted with a part of the hydroxyl groups of 2-HEA to synthesize a solution of an acrylic pressure-sensitive adhesive polymer (A) having a carbon-carbon double bond in the side chain (solid content concentration: 50% by mass, weight average molecular weight Mw: 380,000, solid content hydroxyl value: 21.1 mgKOH / g, solid content acid value: 2.7 mgKOH / g, carbon-carbon double bond content: 1.12 mmol / g). In the above reaction, 0.05 part by mass of hydroquinone monomethyl ether was used as a polymerization inhibitor for maintaining the reactivity of the carbon-carbon double bond.

[0233] Subsequently, with respect to 200 parts by mass (100 parts by mass in terms of solid content) of the solution of the acrylic pressure-sensitive adhesive polymer (A) synthesized above, 2.0 parts by mass of an α-hydroxyalkylphenone-based photoinitiator (trade name: Omnirad184) manufactured by IGM Resins B.V., 0.4 parts by mass of an acylphosphine oxide-based photoinitiator (trade name: Omnirad819) manufactured by IGM Resins B.V., and 2.56 parts by mass (1.15 parts by mass in terms of solid content, 1.75 mmol) of a TDI-based polyisocyanate crosslinking agent (trade name: Coronate L-45E, solid content concentration: 45% by mass) manufactured by Tosoh Corporation as a crosslinking agent were blended, diluted with ethyl acetate, and stirred to prepare a solution of an active energy ray-curable acrylic pressure-sensitive adhesive composition 2(a) having a solid content concentration of 22% by mass.

[0234] 3. Preparation of Solution of Adhesive Composition As the adhesive compositions for the dicing die bond film 3 of the dicing die bond film 20, solutions of the following adhesive compositions 3(a) to 3(d) were prepared.

[0235] (Solution of Adhesive Composition 3(a)) As a wire-embedded type die bond film, the following solution of the adhesive composition solution 3(a) was prepared. First, 26 parts by mass of a bisphenol type epoxy resin (trade name: R2710, epoxy equivalent: 170, molecular weight: 340, liquid at room temperature) manufactured by Printec Co., Ltd. as a thermosetting resin, 36 parts by mass of a cresol novolak type epoxy resin (trade name: YDCN-700-10, epoxy equivalent 210, softening point 80 °C) manufactured by Tohto Kasei Co., Ltd., 1 part by mass of a phenol resin (trade name: Mirex XLC-LL, hydroxyl equivalent: 175, softening point: 77 °C, water absorption rate: 1% by mass, heating mass reduction rate: 4% by mass) manufactured by Mitsui Chemicals, Inc. as a crosslinking agent, 25 parts by mass of a phenol resin (trade name: HE200C-10, hydroxyl equivalent: 200, softening point: 71 °C, water absorption rate: 1% by mass, heating mass reduction rate: 4% by mass) manufactured by Air Water, Inc., 12 parts by mass of a phenol resin (trade name: HE910-10, hydroxyl equivalent: 101, softening point: 83 °C, water absorption rate: 1% by mass, heating mass reduction rate: 3% by mass) manufactured by Air Water, Inc., 15 parts by mass of a silica filler dispersion (trade name: SC2050-HLG, average particle diameter: 0.50 μm) manufactured by Admatechs Co., Ltd. as an inorganic filler, 14 parts by mass of a silica filler dispersion (trade name: SC1030-HJA, average particle diameter: 0.25 μm) manufactured by Admatechs Co., Ltd., 1 part by mass of silica (trade name: Aerosil R972, average particle diameter: 0.016 μm) manufactured by Nippon Aerosil Co., Ltd. were added to the resin composition, cyclohexanone was added as a solvent, stirred and mixed, and further dispersed for 90 minutes using a bead mill.

[0236] Next, to the above resin composition, as a thermoplastic resin A glycidyl group-containing (meth)acrylate copolymer with a low weight-average molecular weight Mw 37 parts by mass, A glycidyl group-containing (meth)acrylate copolymer with a high weight-average molecular weight Mw9 parts by mass, 0.7 parts by mass of γ-ureidopropyltriethoxysilane (trade name: NUC A-1160) manufactured by GE Toshiba Corporation, 0.3 parts by mass of γ-ureidopropyltriethoxysilane (trade name: NUC A-189) manufactured by GE Toshiba Corporation, and 0.03 parts by mass of 1-cyanoethyl-2-phenylimidazole (trade name: Curezol 2PZ-CN) manufactured by Shikoku Kasei Co., Ltd. as a curing accelerator were added, stirred and mixed, filtered through a 100-mesh filter, and then vacuum-degassed to prepare a solution of an adhesive composition 3(a) having a solid content concentration of 20% by mass. The content ratio of each resin component in the total amount of resin components (total mass of the thermoplastic resin, thermosetting resin, and crosslinking agent) was glycidyl group-containing (meth)acrylate copolymer: epoxy resin: phenol resin = 31.5% by mass: 42.5% by mass: 26.0% by mass. Also, the content of the inorganic filler was 20.5% by mass based on the total amount of the resin components. Further, the shear viscosity at 80°C of the die bond film (adhesive layer) 3 formed from the solution of the adhesive composition 3(a) was 3,800 Pa·s.

[0237] (Solution of adhesive composition 3(b)) As for the wire-embedded type die bond film, the following solution of the adhesive composition solution 3(b) was prepared and prepared. First, 21 Quality parts by mass of bisphenol F type epoxy resin (trade name: YDF-8170C, epoxy equivalent: 159, molecular weight: 310, liquid at room temperature) manufactured by Tohto Kasei Co., Ltd. as a thermosetting resin, 33 parts by mass of cresol novolak type epoxy resin (trade name: YDCN-700-10, epoxy equivalent 210, softening point 80°C) manufactured by Tohto Kasei Co., Ltd., 46 parts by mass of phenol resin (trade name: HE200C-10, hydroxyl equivalent: 200, softening point: 71°C, water absorption rate: 1% by mass, heating mass reduction rate: 4% by mass) manufactured by Air Water Co., Ltd. as a crosslinking agent, and 18 parts by mass of silica filler dispersion liquid (trade name: SC1030-HJA, average particle diameter: 0.25 μm) manufactured by Admatechs Co., Ltd. as an inorganic filler were added to the resin composition, cyclohexanone was added as a solvent, stirred and mixed, and further dispersed for 90 minutes using a bead mill.

[0238] Next, to the above resin composition, as a thermoplastic resin A glycidyl group-containing (meth)acrylate copolymer with a low weight-average molecular weight Mw 16 parts by mass, A glycidyl group-containing (meth)acrylate copolymer with a high weight-average molecular weight Mw 64 parts by mass, 1.3 parts by mass of γ-ureidopropyltriethoxysilane (trade name: NUC A-1160) manufactured by GE Toshiba Corporation as a silane coupling agent, 0.6 parts by mass of γ-ureidopropyltriethoxysilane (trade name: NUC A-189) manufactured by GE Toshiba Corporation, and 0.05 parts by mass of 1-cyanoethyl-2-phenylimidazole (trade name: Curezol 2PZ-CN) manufactured by Shikoku Kasei Co., Ltd. as a curing accelerator were added, stirred and mixed, filtered through a 100-mesh filter, and then vacuum-degassed to prepare a solution of an adhesive composition 3(b) having a solid content concentration of 20% by mass. The content ratio of each resin component in the total amount of resin components (total mass of thermoplastic resin, thermosetting resin, and crosslinking agent) was glycidyl group-containing (meth)acrylate copolymer: epoxy resin: phenol resin = 44.4% by mass: 30.0% by mass: 25.6% by mass. Also, the content of the inorganic filler was 10.0% by mass based on the total amount of resin components. Further, the shear viscosity at 80°C of the die bond film (adhesive layer) 3 formed from the solution of the adhesive composition 3(b) was 9,700 Pa·s.

[0239] (Solution of adhesive composition 3(c)) As an adhesive composition solution 3(c) for a wire-embedded type die bond film, the following solution was prepared. First, 11 parts by mass of a bisphenol type epoxy resin (trade name: R2710, epoxy equivalent: 170, molecular weight: 340, liquid at room temperature) manufactured by Printec Co., Ltd. as a thermosetting resin, 40 parts by mass of a dicyclopentadiene type epoxy resin (trade name: HP-7200H, epoxy equivalent: 280, softening point: 83°C) manufactured by DIC Corporation, 18 parts by mass of a bisphenol S type epoxy resin (trade name: EXA-1514, epoxy equivalent: 300, softening point: 75°C) manufactured by DIC Corporation, 1 part by mass of a phenol resin (trade name: Mirex XLC-LL, hydroxyl equivalent: 175, softening point: 77°C, water absorption rate: 1% by mass, heating mass reduction rate: 4% by mass) manufactured by Mitsui Chemicals, Inc. as a crosslinking agent, 20 parts by mass of a phenol resin (trade name: HE200C-10, hydroxyl equivalent: 200, softening point: 71°C, water absorption rate: 1% by mass, heating mass reduction rate: 4% by mass) manufactured by Air Water, Inc., 10 parts by mass of a phenol resin (trade name: HE910-10, hydroxyl equivalent: 101, softening point: 83°C, water absorption rate: 1% by mass, heating mass reduction rate: 3% by mass) manufactured by Air Water, Inc., 24 parts by mass of a silica filler dispersion liquid (trade name: SC1030-HJA, average particle diameter: 0.25 μm) manufactured by Admatechs Co., Ltd. as an inorganic filler, and 0.8 parts by mass of silica (trade name: Aerosil R972, average particle diameter: 0.016 μm) manufactured by Nippon Aerosil Co., Ltd. were added to the resin composition, cyclohexanone was added as a solvent, and the mixture was stirred and mixed, and further dispersed for 90 minutes using a bead mill.

[0240] Next, to the above resin composition, as a thermoplastic resin A glycidyl group-containing (meth)acrylate copolymer with a low weight-average molecular weight Mw 30 parts by mass, A glycidyl group-containing (meth)acrylate copolymer with a high weight-average molecular weight Mw7.5 parts by mass, 0.57 parts by mass of γ-ureidopropyltriethoxysilane (trade name: NUC A-1160) manufactured by GE Toshiba Corporation as a silane coupling agent, 0.29 parts by mass of γ-ureidopropyltriethoxysilane (trade name: NUC A-189) manufactured by GE Toshiba Corporation, and 0.023 parts by mass of 1-cyanoethyl-2-phenylimidazole (trade name: Curezol 2PZ-CN) manufactured by Shikoku Kasei Co., Ltd. as a curing accelerator were added, stirred and mixed, filtered through a 100-mesh filter, and then vacuum degassed to prepare a solution of an adhesive composition 3(c) having a solid content concentration of 20% by mass. The content ratio of each resin component in the total amount of resin components (total mass of the thermoplastic resin, thermosetting resin and crosslinking agent) was glycidyl group-containing (meth)acrylate copolymer: epoxy resin: phenol resin = 27.3% by mass: 50.2% by mass: 22.5% by mass. Also, the content of the inorganic filler was 18.0% by mass based on the total amount of the resin components. Further, the shear viscosity at 80 °C of the die bond film (adhesive layer) 3 formed from the solution of the adhesive composition 3(c) was 3,600 Pa·s.

[0241] (Solution of adhesive composition 3(d)) For general-purpose die bond films, the following solution of an adhesive composition 3(d) was prepared and prepared. First, 54 parts by mass of a cresol novolac type epoxy resin (trade name: YDCN-700-10, epoxy equivalent: 210, softening point: 80 °C) manufactured by Tohto Kasei Co., Ltd. as a thermosetting resin, 46 parts by mass of a phenol resin (trade name: Mirex XLC-LL, hydroxyl equivalent: 175, water absorption rate: 1.8%) manufactured by Mitsui Chemicals, Inc. as a crosslinking agent, and 32 parts by mass of silica (trade name: Aerosil R972, average particle diameter: 0.016 μm) manufactured by Nippon Aerosil Co., Ltd. as an inorganic filler were added to the resin composition, cyclohexanone was added as a solvent, stirred and mixed, and further dispersed for 90 minutes using a bead mill.

[0242] Next, to the above resin composition, as a thermoplastic resin Te gu Lysidyl group-containing (meth)acrylate copolymer Body 274 parts by mass, 5.0 parts by mass of γ-ureidopropyltriethoxysilane (trade name: NUC A-1160) manufactured by GE Toshiba Corporation as a silane coupling agent, 1.7 parts by mass of γ-ureidopropyltriethoxysilane (trade name: NUC A-189) manufactured by GE Toshiba Corporation, and 0.1 part by mass of 1-cyanoethyl-2-phenylimidazole (trade name: Curezol 2PZ-CN) manufactured by Shikoku Kasei Co., Ltd. as a curing accelerator were added, stirred and mixed, filtered through a 100-mesh filter, and then vacuum-degassed to prepare a solution of an adhesive composition 3(d) having a solid content concentration of 20% by mass. The content ratio of each resin component in the total amount of resin components (total mass of the thermoplastic resin, thermosetting resin, and crosslinking agent) was glycidyl group-containing (meth)acrylate copolymer: epoxy resin: phenol resin = 73.3% by mass: 14.4% by mass: 12.3% by mass. Further, the content of the inorganic filler was 8.6% by mass based on the total amount of the resin components. Further, the shear viscosity at 80°C of the die bond film (adhesive layer) 3 formed from the solution of the adhesive composition 3(d) was 30,300 Pa·s.

[0243] 4. Production of a wafer processing adhesive tape (dicing tape) 10 and a dicing die bond film 20 (Example 1) The solution of the above active energy ray-curable acrylic-based adhesive composition (a) was applied to the release-treated surface side of the release liner (thickness 38 μm, polyethylene terephthalate film) so that the thickness of the dried adhesive layer 2 became 10 μm, and after drying the solvent by heating at a temperature of 100°C for 3 minutes, the surface of the base film 1(a) on the first resin layer side was bonded onto the adhesive layer 2 to produce a raw sheet of the dicing tape 10. Thereafter, the raw sheet of the dicing tape 10 was stored at a temperature of 40°C for 48 hours to crosslink and cure the adhesive layer 2.

[0244] Next, a solution of the adhesive composition 3(a) for forming the die bond film (adhesive layer) 3 was prepared, and the solution of the adhesive composition 3(a) was applied to the release-treated surface side of the release liner (thickness: 38 μm, polyethylene terephthalate film) so that the thickness of the die bond film (adhesive layer) 3 after drying would be 30 μm. Then, the solvent was dried by heating in two steps: first at a temperature of 90°C for 5 minutes and then at a temperature of 140°C for 5 minutes, thereby producing a die bond film (adhesive layer) 3 provided with a release liner. If necessary, a protective film (e.g., a polyethylene film or the like) may be laminated on the dried surface side of the die bond film (adhesive layer) 3.

[0245] Subsequently, the die bond film (adhesive layer) 3 provided with the release liner produced above was cut into a circle with a diameter of 335 mm together with the release liner, and the adhesive layer exposed surface (the surface without the release liner) of the die bond film (adhesive layer) 3 was bonded to both surfaces of the adhesive layer 2 of the dicing tape 10 from which the release liner had been peeled. The bonding conditions were 23°C, 10 mm / second, and a linear pressure of 30 kgf / cm.

[0246] Finally, by cutting the dicing tape 10 into a circle with a diameter of 370 mm, a dicing die bond film 20 (DDF(a)) was produced in which a circular die bond film (adhesive layer) 3 with a diameter of 335 mm was laminated on the upper central portion of the adhesive layer 2 of the circular dicing sheet 10 with a diameter of 370 mm.

[0247] (Examples 2 to 19) Dicing die bond films 20 (DDF(b) to DDF(j), DDF(l) to DDF(t)) were produced in the same manner as in Example 1, except that the base film 1(a) was changed to the base films 1(b) to 1(j), 1(l) to 1(t) shown in Tables 1 to 3, respectively.

[0248] (Example 20) Bonding Agent combinationA dicing die bond film 20 (DDF(u)) was produced in the same manner as in Example 2, except that the solution of composition 3(a) was changed to the solution of adhesive composition 3(b).

[0249] (Example 21) Adhesion Agent combination A dicing die bond film 20 (DDF(v)) was produced in the same manner as in Example 2, except that the solution of composition 3(a) was changed to the solution of adhesive composition 3(c).

[0250] (Example 22) Adhesion Agent combination A dicing die bond film 20 (DDF(w)) was produced in the same manner as in Example 2, except that the solution of composition 3(a) was changed to the solution of adhesive composition 3(d) and the thickness of the die bond film (adhesive layer) 3 after drying was changed to 20 μm.

[0251] (Example 23) A dicing die bond film 20 (DDF(x)) was produced in the same manner as in Example 3, except that the thickness of the die bond film (adhesive layer) 3 after drying was changed to 50 μm.

[0252] (Comparative Examples 1 - 6) Dicing die bond films 20 (DDF(y) - DDF(dd)) were produced in the same manner as in Example 1, except that the base film 1(a) was changed to the base films 1(u) - 1(z) shown in Table 4 respectively. Note that for Comparative Example 5, since the base film 1(y) could not be stably formed into a film, the production of the dicing die bond film (DDF(cc)) was not carried out.

[0253] 5. Evaluation Method of Dicing Die Bond Film For the dicing tapes 10 and dicing die bond films 20 (DDF(a) - DDF(j), DDF(l) - DDF(dd)) produced in Examples 1 - 23 and Comparative Examples 1 - 6, various measurements and evaluations were carried out by the methods shown below.

[0254] 5.1 Measurement of the shear viscosity of the die bond film (adhesive layer) 3 at 80°C Each die bond film (adhesive layer) formed from the solutions of the adhesive compositions 3(a) to 3(d) To 3 Regarding this, the shear viscosity at 80°C was measured by the following method. A plurality of die bond films (adhesive layer) 3 from which the release liner had been removed were laminated at 70°C so that the total thickness became 200 to 210 μm to prepare a laminate. Next, the laminate was punched out into a size of 10 mm × 10 mm in the thickness direction to obtain a measurement sample. Subsequently, using a dynamic viscoelasticity apparatus ARES (manufactured by Rheometric Scientific, Inc.), after attaching a circular aluminum plate jig with a diameter of 8 mm, the measurement sample was set. While applying a 5% strain to the measurement sample at 35°C, the shear viscosity was measured while raising the temperature of the measurement sample at a temperature increase rate of 5°C / min, and the value of the shear viscosity at 80°C was obtained.

[0255] 5.2 Evaluation of the stealth dicing property of the dicing die bond film 20 5.2.1 Cutability of the die bond film (adhesive layer) 3 First, a semiconductor wafer (silicon mirror wafer, thickness 750 μm, outer diameter 12 inches) W was prepared, and a commercially available back grind tape was attached to one surface. Next, from the surface opposite to the side where the back grind tape of the semiconductor wafer W was attached, using a stealth dicing laser saw (device name: DFL7361) manufactured by DISCO Corporation, along the lattice-shaped division planned lines, so that the size of the semiconductor chip 30a after dicing became 4.5 mm × 7.0 mm, laser light was irradiated under the following conditions to form a modified region 30b at a predetermined depth position of the semiconductor wafer W.

[0256] · Laser irradiation conditions (1) Laser oscillator type: Semiconductor laser-excited Q-switch solid-state laser (2) Wavelength: 1342 nm (3) Oscillation mode: Pulse (4) Frequency: 90 kHz (5) Output: 1.7 W (6) Moving speed of the mounting table of the semiconductor wafer: 700 mm / second

[0257] Next, using a back grinding apparatus (apparatus name: DGP8761) manufactured by DISCO Corporation, the semiconductor wafer W with a thickness of 750 μm in which the modified region 30b held on the back grinding tape was formed was ground and thinned to obtain a semiconductor wafer 30 with a thickness of 30 μm. In the stage of the back grinding (grinding) process, the semiconductor wafer 30 was divided into semiconductor chips 30a of a predetermined size on the back grinding tape by cracks progressing vertically starting from the modified region 30b formed on the dividing line. Subsequently, by performing the cool expand process by the following method, the cuttability of the adhesive layer 3, which is one of the index items of stealth dicing property, was evaluated. Specifically, on the surface opposite to the side to which the back grinding tape of a plurality of semiconductor chips 30a with a thickness of 30 μm obtained by the above method was attached, the peeling liner was peeled from the dicing die bond film 20 prepared in each example and comparative example so that the exposed adhesive layer 3 adhered. Using a laminating apparatus (apparatus name: DFM2800) manufactured by DISCO Corporation, the dicing die bond film 20 was laminated on the plurality of semiconductor chips 30a under the conditions of a lamination temperature of 70°C and a lamination speed of 10 mm / second, and a ring frame (wafer ring) 40 was attached to the exposed portion of the adhesive layer 2 at the outer edge of the dicing tape 10. Then, the back grinding tape was peeled off, and the plurality of semiconductor chips 30a were transferred and fixed onto the die bond film 3 of the dicing die bond film 20. Here, the dicing die bond film 20 is attached to a plurality of semiconductor chips 30a, which are divided bodies of the semiconductor wafer 30, so that the MD direction of the base film 1 thereof coincides with the longitudinal line direction of the lattice-like dividing line of the semiconductor wafer 30 (the TD direction of the base film 1 and the horizontal line direction of the lattice-like dividing line of the semiconductor wafer 30).

[0258] A laminate (a plurality of semiconductor chips 30a / adhesive layer 3 / adhesive layer 2 / base film 1) including a plurality of semiconductor chips 30a held on the above-described ring frame (wafer ring) 40 was fixed to an expandable device (device name: DDS2300 Fully Automatic Die Separator) manufactured by DISCO Corporation. Next, under the following conditions, the dicing tape 10 (adhesive layer 2 / base film 1) of the dicing die bond film 20 with the semiconductor wafer 30 was cooled and expanded to cut the adhesive layer 3. As a result, semiconductor chips 30a with a die bond film (adhesive layer) 3 were obtained. In this example, the cool expansion process was carried out under the following conditions. However, the expansion conditions (such as "expansion speed" and "expansion amount") may be appropriately adjusted according to the physical properties of the base film 1 and temperature conditions, etc., and then the cool expansion process may be carried out.

[0259] · Conditions of the cool expansion process (1) Temperature: -15°C, Cooling time: 80 seconds (2) Expansion speed: 200 mm / second (3) Expansion amount: 11 mm (4) Standby time: 0 seconds

[0260] Regarding the adhesive layer 3 after cool expansion, from the surface side of the semiconductor chip 30a, using an optical microscope (model: VHX-1000) manufactured by KEYENCE CORPORATION and observing at a magnification of 200 times, the number of uncut sides among the sides to be cut was measured. Then, for each of the adhesive layers 3, from the total number of sides to be cut and the total number of uncut sides, the ratio of the number of cut sides to the total number of sides to be cut was calculated as the cutting rate (%). The observation with the optical microscope was performed for all of the semiconductor chips 30a. According to the following criteria, the cuttability of each of the adhesive layers 3 was evaluated, and an evaluation of B or higher was determined to have good cuttability.

[0261] A: The cutting rate was 95% or more and 100% or less. B: The cutting rate was 90% or more and less than 95%. C: The cutting rate was less than 90%.

[0262] 5.2.2 Confirmation of relaxation elimination of dicing tape 10 after the heat shrinkage process After releasing the above cool expand state, again, using an expand device (device name: DDS2300 Fully Automatic Die Separator) manufactured by DISCO Corporation, a normal temperature expand process was carried out at the following conditions using its heat expander unit.

[0263] · Conditions of the normal temperature expand process (1) Temperature: 23°C (2) Expand speed: 30 mm / second (3) Expand amount: 9 mm (4) Standby time: 15 seconds

[0264] Next, while maintaining the expand state, the dicing tape 10 was adsorbed by the adsorption table, and the adsorption table was lowered together with the work while maintaining the adsorption by the adsorption table. Then, a heat shrinkage process was carried out at the following conditions to heat-shrink (heat-shrink) the circumferential portion outside the semiconductor chip 30a holding region in the dicing tape 10. The surface temperature of the heated portion of the dicing tape 10 was 80°C.

[0265] · Conditions of the heat shrinkage process (1) Hot air temperature: 220°C (2) Air volume: 40 L / min (3) Distance between the hot air outlet and the dicing tape 10: 20 mm (4) Rotation speed of the stage: 7° / second

[0266] Subsequently, after releasing the dicing tape 10 from the adsorption by the adsorption table, the workpiece was removed from the expansion device, placed on a flat rubber mat, and the degree of relaxation elimination in the circumferential portion outside the semiconductor chip 30a holding region in the dicing tape 10 after heat shrinkage (heat shrink) was visually confirmed under a three-wavelength fluorescent lamp. According to the following criteria, the degree of relaxation elimination for each of the dicing tapes 10 was evaluated, and a rating of B or higher was judged to have good heat shrinkability.

[0267] A: No relaxation was confirmed. B: Wavy relaxation was confirmed in a very small part but was minor. C: Wavy relaxation or deformed wrinkles were clearly confirmed.

[0268] 5.2.3 Confirmation of kerf width after the heat shrink process After the above heat shrink process, the workpiece was removed from the expansion device, and the distance (kerf width) between adjacent semiconductor chips 30a was observed and measured at a magnification of 200 times using an optical microscope (model: VHX-1000) manufactured by Keyence Corporation from the surface side of the semiconductor wafer 30, thereby evaluating the expandability and heat shrinkability of the dicing tape 10 in the dicing die bond film 20.

[0269] Specifically, at four locations (two locations of kerf MD1 and kerf MD2 in the MD direction of the base film 1, two locations of kerf TD1 and kerf TD2 in the TD direction of the base film 1, see FIG. 14) of one cut cross line portion formed by four adjacent semiconductor chips 30a at the center portion 31 of the semiconductor wafer 30 shown in FIG. 13, at seven locations (three locations of kerf MD3 to kerf MD5 in the MD direction, four locations of kerf TD3 to kerf TD6 in the TD direction, not shown) of two cut cross line portions formed by six adjacent semiconductor chips 30a at the left portion 32, at seven locations (three locations of kerf MD6 to kerf MD8 in the MD direction, four locations of kerf TD7 to kerf TD10 in the TD direction, not shown) of two cut cross line portions formed by six adjacent semiconductor chips 30a at the right portion 33, at seven locations (four locations of kerf MD9 to kerf MD12 in the MD direction, three locations of kerf TD11 to kerf TD13 in the TD direction, not shown) of two cut cross line portions formed by six adjacent semiconductor chips 30a at the upper portion 34, and at seven locations (four locations of kerf MD13 to kerf MD16 in the MD direction, three locations of kerf TD14 to kerf TD16 in the TD direction, not shown) of two cut cross line portions formed by six adjacent semiconductor chips 30a at the lower portion 35, a total of 32 locations (16 locations in the MD direction and 16 locations in the TD direction), the separation distance between adjacent semiconductor chips 30a was measured respectively, and the average value of the 16 locations in the MD direction was calculated as the kerf width in the MD direction, and the average value of the 16 locations in the TD direction was calculated as the kerf width in the TD direction. According to the following criteria, the extensibility and thermal shrinkage of the dicing tape 10 in the dicing die bond film 20 were evaluated, and it was determined that an evaluation of B or higher indicated that the extensibility and thermal shrinkage were good, that is, the kerf width was ensured at a level where problems were unlikely to occur in the pickup process.

[0270] A: The values of both the kerf width in the MD direction and the kerf width in the TD direction were 30 μm or more. B: The value of the curl width in the MD direction is 30 μm or more, and the value of the curl width in the TD direction is 25 μm or more and less than 30 μm, or the value of the curl width in the TD direction is 30 μm or more, and the value of the curl width in the MD direction is 25 μm or more and less than 30 μm, or the value of either the MD direction curl width or the TD direction curl width is 25 μm or more and less than 30 μm. C: The value of at least one of the MD direction curl width and the TD direction curl width was less than 25 μm.

[0271] 5.2.4 Picking up of the dicing tape 10 in the dicing die bond film 20 Evaluation of pick-up property From the base film 1 side of the dicing tape 10 holding the semiconductor chip 30a with the die bond film (adhesive layer) 3a that has been severed and individualized by the above expansion process, ultraviolet light (UV) with a central wavelength of 365 nm is irradiated at an irradiation intensity of 70 mW / cm2 so that the integrated light amount becomes 150 mJ / cm2 to cure the adhesive layer 2, thereby obtaining an evaluation sample for pick-up property.

[0272] Subsequently, a pick-up test was conducted using a device (device name: die bonder DB-830P) having a pick-up mechanism manufactured by Fast Forward Technology Co., Ltd. (formerly manufactured by Hitachi High-Technologies Corporation). The size of the pick-up collet was 4.4 × 6.9 mm, the number of pins of the push-up pins was 12, and for the pick-up conditions, the push-up speed of the push-up pins was 10 mm / second, and the push-up height of the push-up pins was 100 μm. The number of samples for the pick-up trials was 20 (chips) at a predetermined position, and according to the following criteria, the pick-up property of the dicing tape 10 in the dicing die bond film 20 was evaluated, and an evaluation of B or higher was judged to have good pick-up property.

[0273] A: 20 chips were continuously picked up, and the number of chips without chip cracking or pick-up failure (number of successful pick-ups) was 20. The pick-up success rate was 100%. B: Twenty chips were continuously picked up, and the number of chips without chip cracking or pickup failure (the number of successful pickups) was 19. The pickup success rate was 95%. C: Twenty chips were continuously picked up, and the number of chips without chip cracking or pickup failure (the number of successful pickups) was 18 or less. The pickup success rate was 90% or less.

[0274] 6. Evaluation Results For each evaluation result of the dicing die bond films 20 (DDF(a) to DDF(j), DDF(l) to DDF(dd)) prepared in Examples 1 to 23 and Comparative Examples 1 to 6, the composition of the dicing die bond film 20 (the type of the adhesive composition, the type of the adhesive composition, the shear viscosity, and the thicknesses of the adhesive layer and the adhesive layer) and the composition of the base film 1 used (the content ratios of methacrylic acid and isobutyl acrylate and the zinc ion concentration of the ionomer resin used in each resin layer, the Vicat softening temperature of the entire resin used in each resin layer, the thickness) are shown in Tables 1 to 5 together.

[0275] [Table 1]

[0276] [Table 2]

[0277] [Table 3]

[0278] [Table 4]

[0279] [Table 5]

[0280] First, as shown in Tables 1 to 4, for the dicing die bond films (DDF(a) to DDF(j), DDF(l) to DDF(x)) of Examples 1 to 23 using the adhesive tape for wafer processing that satisfies the requirements of the present invention, after the adhesive layer is divided, the semiconductor chip with the adhesive layer can be fixed on the adhesive layer of the adhesive tape for wafer processing (dicing tape) with a sufficient kerf width ensured. As a result, it was confirmed that the pick-up property was good. That is, the dicing die bond film using the adhesive tape for wafer processing of the present invention uses, as the base film, a resin film in which a resin layer containing an ethylene-unsaturated carboxylic acid copolymer containing a structural unit derived from an unsaturated carboxylic acid at a specific content ratio is crosslinked with zinc ions at a specific concentration and has an appropriate Vicat softening temperature. Therefore, it has both an appropriate tensile stress and uniform expandability during expansion, and shrinkability during the heat shrinkage process. The adhesive layer can be well divided by expansion, and the slack generated in the tape during expansion can be removed by heat shrinkage. As a result, the kerf width between the semiconductor chips with the adhesive layer ensured by expansion is appropriately maintained, and damage caused by contact between chips and re-adhesion caused by contact between the adhesive layers are less likely to occur. Thus, it was found that the semiconductor chips with the adhesive layer can be picked up well. And even when an adhesive layer that is thick and has high fluidity, such as a wire-embedded die bond film, is used as the adhesive layer, it was found that the adhesive layer can be divided as well as a normal general-purpose die bond film, and the semiconductor chips with the adhesive layer can be picked up well.

[0281] When comparing the examples in detail, first, when comparing the dicing die bond films of Examples 1 to 15 in which the content ratio of the specific ionomer resin in each resin layer is 100% by mass and the total thickness of the resin layers (the first resin layer, the second resin layer, and the third resin layer) containing the specific ionomer resin at a content ratio of 80% by mass or more is 100% of the total thickness of the base film, zinc (Zn) per 1 g of the ethylene-unsaturated carboxylic acid copolymer 2+)In Examples 2 to 8, 12, 13, and 15 where the ion concentration is in the range of 0.41 mmol or more and 0.60 mmol or less, in the evaluation of the segmentation property of the adhesive layer, the kerf width after heat shrinkage, and the pick-up property of the dicing die bond film, zinc (Zn) per 1 g of the ethylene-unsaturated carboxylic acid copolymer 2+ )It was found that it is superior to the die bond films of Examples 1, 9 to 11, and 14 where the ion concentration is 0.38 mmol. Also, zinc (Zn) per 1 g of the ethylene-unsaturated carboxylic acid copolymer 2+ )Although the ion concentration is in the range of 0.41 mmol or more and 0.60 mmol or less, the dicing die bond films of Examples 12 and 13 where the content ratio of the structural unit (isobutyl acrylate) derived from the unsaturated carboxylic acid ester in the ethylene-unsaturated carboxylic acid copolymer is as low as 1.5% by mass are compared with the dicing die films of Examples 2 to 8 and 15 where the content ratio of isobutyl acrylate in the ethylene-unsaturated carboxylic acid copolymer is 5% by mass or more. The result was slightly inferior.

[0282] Also, from the evaluation results of the dicing die bond films of Examples 2, 20 to 22 using die bond films with the same composition of the dicing tape 10 but different shear viscosity characteristics at 80°C and the dicing die bond film of Example 23 where the thickness of the die bond film was increased to 50 μm compared to 30 μm of Example 3, the adhesive tape for wafer processing of the present embodiment uses any die bond film (adhesive layer) of the wire-embedded type die bond film and the general-purpose die bond film. It was found that the segmentation property of the adhesive layer is generally good, the kerf width after heat shrinkage is sufficiently ensured, and the pick-up property is also good.

[0283] Furthermore, the dicing die bond film of Example 16 having a base film with a three-layer structure of two resins using an ionomer resin (IO-2) as the resin composition for the first resin layer and the second resin layer, and a resin (IO-2 / PA) obtained by mixing an ionomer resin and a polyamide resin at a mass ratio of 90:1 as the resin composition for the third resin layer, was found to be as excellent as the dicing die bond film of Example 2 having a base film with a three-layer structure of one resin using only the ionomer resin (IO-2). However, the dicing die bond film of Example 17 having a base film with a two-layer structure of two resins using an ionomer resin (IO-2) as the resin composition for the first resin layer and a resin (IO-2 / TPO-1) obtained by mixing an ionomer resin and an olefin-based thermoplastic elastomer resin at a mass ratio of 80:20 as the resin composition for the second resin layer, although it was at a practically acceptable level, showed slightly inferior results compared to the dicing die bond film of Example 2.

[0284] Furthermore, the dicing die bond film of Example 18 having a base film with a three-layer structure of two resins using an ionomer resin (IO-2) as the resin composition for the first resin layer and the third resin layer, and an olefin-based thermoplastic elastomer resin (TPO-1) as the resin composition for the second resin layer, and having a total thickness of the resin layers containing a specific ionomer resin at a content ratio of 80% by mass or more being 89% of the total thickness of the base film, and the dicing die bond film of Example 19 having a base film with a three-layer structure of two resins using an ionomer resin (IO-2) as the resin composition for the first resin layer and the second resin layer, and an olefin-based thermoplastic elastomer resin (TPO-2) as the resin composition for the third resin layer, and having a total thickness of the resin layers containing a specific ionomer resin at a content ratio of 80% by mass or more being 67% of the total thickness of the base film, although they were at a practically acceptable level respectively, showed slightly inferior results compared to the dicing die bond film of Example 2.

[0285] In contrast, as shown in Table 5, in Comparative Examples 1 to 6 using an adhesive tape for wafer processing that does not meet the requirements of the present invention, the dicing die bond films (DDF(y) to DDF(dd)) were all inferior to the dicing die bond films of Examples 1 to 23 in terms of the evaluation of the segmentability of the adhesive layer, the kerf width after heat shrinkage, and the pick-up property.

[0286] Specifically, the dicing die bond film of Comparative Example 1 having a base film of a three-layer structure of a single resin using only an ionomer resin (IO-16) in which the zinc (Zn 2+ ) ion concentration per 1 g of the ethylene-unsaturated carboxylic acid copolymer is less than 0.38 mmol had a small tensile stress, insufficient segmentability of the adhesive layer, and insufficient shrinkage during heat shrinkage, and thus could not secure a sufficient kerf width. Therefore, compared with the dicing die bond films of Examples 1 to 15, the pick-up property was inferior.

[0287] Also, the content ratio of the structural unit (methacrylic acid) derived from the unsaturated carboxylic acid in the ethylene-unsaturated carboxylic acid copolymer is less than 6.9% by mass, and the zinc (Zn 2+ ) ion concentration per 1 g of the ethylene-unsaturated carboxylic acid copolymer is less than 0.38 mmol. The dicing die bond film of Comparative Example 2 having a base film of a three-layer structure of a single resin using only the ionomer resin (IO-17) was also inferior in pick-up property compared with the dicing die bond films of Examples 1 to 15, similar to the dicing die bond film of Comparative Example 1.

[0288] Furthermore, the content ratio of the structural unit (methacrylic acid) derived from the unsaturated carboxylic acid in the ethylene-unsaturated carboxylic acid copolymer exceeds 18.0% by mass, and the zinc (Zn 2+)The dicing die bond film of Comparative Example 3 having a base film with a three-layer structure of a single resin using only an ionomer resin (IO-18) with an ion concentration of less than 0.38 mmol and a Vicat softening temperature of less than 50°C was also inferior in pick-up property compared to the dicing die bond films of Examples 1 to 15, similar to the dicing die bond film of Comparative Example 1. During the dicing tape processing, partial blocking occurred on the winding core side of the raw roll, so the evaluation was conducted on the non-blocking part.

[0289] Furthermore, the content ratio of the structural unit (methacrylic acid) derived from the unsaturated carboxylic acid in the ethylene-unsaturated carboxylic acid copolymer is less than 6.9% by mass, and the zinc (Zn) per 1 g of the ethylene-unsaturated carboxylic acid copolymer 2+ )The dicing die bond film of Comparative Example 4 having a base film with a three-layer structure of a single resin using only an ionomer resin (IO-19) with an ion concentration of less than 0.38 mmol and a Vicat softening temperature exceeding 80°C is presumed to have had a necking phenomenon during expansion, but its expandability was insufficient, resulting in insufficient segmentation of the adhesive layer and insufficient securing of the kerf width. Also, the shrinkage during heat shrinkage was insufficient, and the kerf width could not be secured sufficiently. Therefore, compared to the dicing die bond films of Examples 1 to 15, the pick-up property was inferior.

[0290] Furthermore, to a resin layer made of an ethylene-methacrylic acid copolymer (EMAA) with a Vicat softening temperature of 80°C or higher, zinc (Zn) per 1 g of the ethylene-unsaturated carboxylic acid copolymer 2+ )The dicing die bond film of Comparative Example 6 having a base film with a two-layer structure of two resins in which a resin layer made of an ionomer resin (IO-16) with an ion concentration of less than 0.38 mmol is laminated was also inferior in pick-up property compared to the dicing die bond films of Examples 1 to 23, similar to the dicing die bond film of Comparative Example 1.

[0291] Regarding Comparative Example 5, since stable film formation of the base film 1(y) was not possible, it could not be evaluated as a dicing die bond film.

Explanation of Signs

[0292] 1…Base film, 2…Adhesive layer, 3, 3a1, 3a2…Die bond film (adhesive layer, adhesive film), 4…Support substrate for mounting semiconductor chips, 5…External connection terminal, 6…Terminal, 7…Wire, 8…Sealing material, 9…Support member, 10…Dicing tape, 11…OPP film base single-sided adhesive tape (backing tape), 12…Paper double-sided adhesive tape (fixing tape), 13…Flat cross stage, 14…PET film base single-sided adhesive tape (backing tape, fixing tape), 15…SUS plate, 20…Dicing die bond film, W, 30…Semiconductor wafer, 30a, 30a1, 30a2…Semiconductor chip, 30b…Modified region, 31…Center part of semiconductor wafer, 32…Left part of semiconductor wafer, 33…Right part of semiconductor wafer, 34…Upper part of semiconductor wafer, 35…Lower part of semiconductor wafer, 40…Ring frame (wafer ring), 41…Holder, 50…Suction collet, 60…Pushing pin (needle), 70, 80…Semiconductor device.

Claims

1. An expandable adhesive tape for wafer processing used when dividing an adhesive layer along a chip by expansion, comprising a base film and an adhesive layer provided on the base film, The base film comprises at least a first resin layer containing an ionomer resin at a content ratio of 80% by mass or more, and a second resin layer containing an ionomer resin of the same or different type as the ionomer resin at a content ratio of 80% by mass or more, and has a laminated structure of two or more layers, Each of the ionomer resins comprises an ethylene-unsaturated carboxylic acid copolymer which is a base polymer of the resin and zinc ions, and is made of a resin having a Vicat softening temperature defined by JIS K7206 within a range having a lower limit value of 50°C and an upper limit value of 79°C, The ethylene-unsaturated carboxylic acid copolymer has a content ratio of structural units derived from unsaturated carboxylic acid within a range having a lower limit value of 6.9% by mass and an upper limit value of 18.0% by mass when the total amount of structural units constituting the ethylene-unsaturated carboxylic acid copolymer is 100% by mass based on the total amount, The concentration of the zinc ions has a value within a range having a lower limit value of 0.38 mmol per 1 g of the ethylene-unsaturated carboxylic acid copolymer and an upper limit value of 0.60 mmol, an adhesive tape for wafer processing.

2. The ethylene-unsaturated carboxylic acid copolymer has a content ratio of structural units derived from unsaturated carboxylic acid within a range of 8.0% by mass or more and 15.0% by mass or less when the total amount of structural units constituting the ethylene-unsaturated carboxylic acid copolymer is 100% by mass based on the total amount, the adhesive tape for wafer processing according to Claim 1.

3. The concentration of the zinc ions has a value within a range of 0.41 mmol or more and 0.55 mmol or less per 1 g of the ethylene-unsaturated carboxylic acid copolymer, the adhesive tape for wafer processing according to Claim 1.

4. The total thickness of the base film is within a range of 60 μm or more and 150 μm or less, the thickness of each resin layer containing the ionomer resin at a content ratio of 80% by mass or more in the base film is within a range of 10 μm or more and 50 μm or less, and the total thickness of all resin layers containing the ionomer resin at a content ratio of 80% by mass or more is 65% or more of the total thickness of the base film, the adhesive tape for wafer processing according to Claim 1.

5. The adhesive tape for wafer processing according to claim 1, wherein the ethylene-unsaturated carboxylic acid copolymer is composed of at least one copolymer selected from the group consisting of a binary copolymer of ethylene and (meth)acrylic acid and a terpolymer of ethylene, (meth)acrylic acid, and an alkyl (meth)acrylate.

6. A method for manufacturing a semiconductor chip or a semiconductor device, which uses the adhesive tape for wafer processing according to any one of claims 1 to 5.

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