Base film for semiconductor manufacturing tape

Abstract

To provide a base film for a semiconductor manufacturing tape, which is excellent in uniform elongation, rigidity, and processing stability.SOLUTION: Provided is a base film for a semiconductor manufacturing tape, which contains a homopolymer of 1-butene and low-density polyethylene having a density of 0.93 g / cm3 or less. The mass ratio ([homopolymer of 1-butene]:[low-density polyethylene]) of the homopolymer of 1-butene relative to the low-density polyethylene is 10:90-70:30.SELECTED DRAWING: None

Description

Technical Field

[0001] The present invention relates to a base film for a semiconductor manufacturing tape (hereinafter, may be simply referred to as "base film").

Background Art

[0002] As a method for manufacturing a semiconductor device such as an IC chip, for example, a wafer circuit having a circuit formed on a substantially disk-shaped semiconductor wafer is diced on a semiconductor manufacturing tape (dicing tape) for a wafer to obtain individual semiconductor devices. This method is widely used. After dicing, for example, the dicing tape is stretched to form a gap between the semiconductor devices (i.e., expanded), and then each semiconductor device is picked up by a robot or the like.

[0003] Further, as a semiconductor manufacturing tape for a wafer, a dicing / die attach film (DDAF) in which an adhesive layer is laminated on the adhesive layer of the above-described dicing tape is used. After the wafer circuit is diced on the dicing / die attach film, the dicing / die attach film is stretched to form a gap between the semiconductor devices, and then the adhesive layer is photocured, and the semiconductor device is peeled off from the adhesive layer and picked up in a state where the adhesive layer is adhered.

[0004] Dicing tapes and dicing / die attach films generally include an adhesive layer for fixing a wafer and a base film containing polyolefin or the like. For example, the base film contains 30 to 100% by weight of an amorphous polyolefin having a content of a propylene and / or 1-butene component of 50% by weight or more, 0 to 70% by weight of a crystalline polypropylene-based resin, and 0 to 70% by weight of a polyethylene-based resin. A dicing tape provided with a base film constituted by a laminate of a polyolefin layer (intermediate layer) and a polyethylene-based resin layer (surface layer) formed of a polyethylene-based resin such as low-density polyethylene laminated on both surfaces of the polyolefin layer has been proposed (see, for example, Patent Document 1).

[0005] In addition, a base material film composed of a laminate including an intermediate layer containing at least 40% by mass or more of an amorphous polyolefin containing at least one component selected from the group consisting of ethylene, propylene, and 1-butene, and surface layers laminated on both sides of the intermediate layer and mainly composed of crystalline polyethylene has been proposed (see, for example, Patent Document 2).

[0006] In addition, a random copolymer of propylene with ethylene and / or an α-olefin having 4 to 8 carbon atoms, wherein the content of ethylene and / or an α-olefin having 4 to 8 carbon atoms is 6% by weight or more, and the density measured in accordance with ASTM D1505 is 885 kg / m 3 A base material film composed of a laminate including an intermediate layer mainly composed of the following propylene-based random copolymer (β), and surface layers laminated on both sides of the intermediate layer and mainly composed of a propylene-based random copolymer (α) having a lower content of ethylene and / or an α-olefin having 4 to 8 carbon atoms and a higher density than the propylene-based random copolymer (β) has been proposed (see, for example, Patent Document 3).

Prior Art Documents

Patent Documents

[0007]

Patent Document 1

Patent Document 2

Patent Document 3

Summary of the Invention

Problems to be Solved by the Invention

[0008] However, in the base film described in Patent Document 1, since the same amount or more of crystalline random polypropylene is added to the amorphous butene copolymer, necking occurs when the base film is stretched, and there is a problem that the uniform stretchability (uniform expandability) of the base film is insufficient. Further, since a low-viscosity butene copolymer is used, the thickness variation due to discharge variations such as draw resonance when forming the base film becomes large, and there is a problem that the processing stability of the base film is insufficient.

[0009] Further, in the base film described in Patent Document 2, since the rigidity of the base film is insufficient, there is a problem that the unwinding of the base material becomes unstable in the manufacturing process of the base film.

[0010] Further, in the base film described in Patent Document 3, since a semi-crystalline resin instead of an amorphous resin is used, necking occurs when forming the base film, and there is a problem that the uniform stretchability of the base film is insufficient. Further, since the rigidity of the base film is insufficient, there is a problem that the unwinding of the base material becomes unstable in the manufacturing process of the base film. Further, since the surface of the base film has high adhesiveness, the base film adheres to the conveying roll when the base film is conveyed, making it difficult to convey and wind up the base film, and blocking occurs when winding up the base film, and there is a problem that the processing stability is insufficient.

[0011] Therefore, the present invention has been made in view of the above problems, and an object thereof is to provide a base film for a semiconductor manufacturing tape excellent in uniform stretchability, rigidity, and processing stability.

Means for Solving the Problems

[0012] To achieve the above object, the base film for a semiconductor manufacturing tape of the present invention comprises a homopolymer of 1-butene and a density of 0.93 g / cm 3It contains low-density polyethylene as follows, and is characterized in that the mass ratio of the homopolymer of 1-butene to low-density polyethylene is 10:90 to 70:30, i.e., homopolymer of 1-butene:low-density polyethylene = 10:90 to 70:30.

Advantages of the Invention

[0013] According to the present invention, it becomes possible to provide a base film for a semiconductor manufacturing tape that is excellent in uniform stretchability, rigidity, and processing stability.

Brief Description of the Drawings

[0014]

Figure 1

Figure 2

Modes for Carrying Out the Invention

[0015] Hereinafter, the base film for a semiconductor manufacturing tape of the present invention will be specifically described. Note that the present invention is not limited to the following embodiments, and can be appropriately changed and applied without changing the gist of the present invention.

[0016] The base film of the present invention is a film formed of a polyolefin resin, and contains a homopolymer of 1-butene and low-density polyethylene having a density of 0.93 g / cm 3 as follows.

[0017] <Homopolymer of 1-butene> In the present invention, as the polybutene, a homopolymer obtained by polymerizing 1-butene alone is used. This homopolymer of 1-butene has a high molecular weight and bulky side chains, and due to the strong intermolecular force caused by these bulky side chains, although it is a crystalline polymer, it can improve the uniform stretchability of the base film in the same manner as in the amorphous case.

[0018] In addition, as the homopolymer of 1-butene used in this embodiment, those having a weight-average molecular weight (Mw) of about 500,000 to 1,500,000 can be used.

[0019] The above-mentioned "weight-average molecular weight" refers to the value calculated in accordance with JIS K 7252-1:2016.

[0020] Since the homopolymer of 1-butene used in the present invention has a high molecular weight, it has low surface tackiness and can be used as a surface layer. Also, compared with amorphous polyolefin, it has high rigidity, so in the manufacturing process of the base film, a base film with high rigidity that enables unwinding of the base material can be provided.

[0021] In addition, although the homopolymer of 1-butene used in the present invention has a high molecular weight, it can be molded with a general-purpose extruder. Since the high molecular weight component reduces the surface tackiness of the film, it is possible to suppress adhesion to the conveying rolls when conveying the base film, and to suppress blocking when winding up the base film and draw resonance when forming the base film, thereby improving the processing stability of the base film.

[0022] From the above, by using the homopolymer of 1-butene as the resin for forming the base film, the uniform stretchability, rigidity, and processing stability of the base film can be improved.

[0023] <Low-density polyethylene> In the present invention, the density of the low-density polyethylene is 0.930 g / cm 3 or less. When the density is 0.930 g / cm 3 or less, an excessive increase in crystallinity is suppressed and flexibility is improved, so the isotropy of the base film can be improved. When the density is 0.930 g / cm 3If it is larger than this, the crystallinity may increase excessively, resulting in a decrease in isotropy. Also, since the rigidity becomes too high, the pick-up property of the semiconductor device may decrease, and the semiconductor device may be damaged.

[0024] Also, from the viewpoint of improving processing stability, the density of the low-density polyethylene is preferably 0.860 g / cm 3 or more, and more preferably 0.880 g / cm 3 or more.

[0025] In addition, since linear low-density polyethylene has side-chain branches in the linear structure of high-density polyethylene, compared with high-density polyethylene, its crystallinity does not increase too much and it has excellent flexibility.

[0026] Note that, from the viewpoint of strength, linear low-density polyethylene produced using a metallocene catalyst or a Ziegler catalyst may be used.

[0027] Also, the melt mass flow rate (MFR) of the linear low-density polyethylene is preferably 0.5 to 7.5 g / 10 min, more preferably 1.0 to 6.0 g / 10 min, and even more preferably 2.0 to 5.0 g / 10 min. When the melt mass flow rate (MFR) is 0.5 g / 10 min or more, the molecular weight is not too large, and flexibility and processability can be improved. When it is 7.5 g / 10 min or less, the molecular weight is not too small, and processing stability can be improved.

[0028] Note that the above melt mass flow rate can be obtained by measuring in accordance with the provisions of JIS K7210:1999.

[0029] From the above, by using low-density polyethylene with a density of 0.93 g / cm 3 or less as the resin for forming the base film, the flexibility and isotropy of the base film can be improved.

[0030] <Base film> In the base film of the present invention, the mass ratio of the homopolymer of 1-butene to low-density polyethylene is in the range of homopolymer of 1-butene:low-density polyethylene = 10:90 to 70:30. By setting the mass ratio of the homopolymer of 1-butene to low-density polyethylene within this range, the occurrence of necking during the formation of the base film can be prevented, enabling uniform expansion, and enabling the unwinding of the base material during the manufacturing process of the base film. Furthermore, it becomes possible to prevent the occurrence of blocking when winding up the base film and the thickness variation due to draw resonance when forming the base film. Therefore, it becomes possible to provide a base film excellent in uniform stretchability, rigidity, and processing stability.

[0031] Also, in the base film of the present invention, from the viewpoint of further improving the uniform stretchability of the base film, in the machine axis (longitudinal) direction (hereinafter referred to as "MD") of the base film and the direction orthogonal thereto (hereinafter referred to as "TD"), the ratio of the stress (at 40% elongation) to the stress (at 20% elongation) (that is, the elongation rate of the base film) is preferably 1 or more and 2 or less, more preferably 1.05 or more and 1.8 or less, and even more preferably 1.1 or more and 1.7 or less. When the elongation rate of the base film is greater than 2, it may become difficult to hold the expand ring due to excessive stress increase. When the elongation rate of the base film is less than 1, necking may occur, making uniform expansion difficult.

[0032] Also, the stress (at 25% elongation) in MD and TD is preferably 5 MPa or more and 20 MPa or less, more preferably 6 MPa or more and 15 MPa or less, and even more preferably 7 MPa or more and 13 MPa or less. When the stress is greater than 20 MPa, the rigidity becomes too high, resulting in a decrease in the pick-up property of the semiconductor device and possible damage to the semiconductor device. When the stress is less than 5 MPa, the rigidity is low, making it difficult to unwind the base material during the manufacturing process of the base film and possibly reducing the coatability of the adhesive.

[0033] Further, from the viewpoint of suppressing the occurrence of slack due to the isotropy of the base film during expansion, the ratio of the stress in the MD (at 25% elongation) to the stress in the TD (at 25% elongation) (i.e., the stress ratio of the base film at 25% elongation) is preferably 0.8 or more and 1.3 or less, more preferably 0.85 or more and 1.15 or less, and even more preferably 0.9 or more and 1.1 or less.

[0034] Note that the above-mentioned "stress" refers to the stress measured in accordance with JIS K7161-2:2014.

[0035] The thickness of the base film is preferably 50 to 300 μm, more preferably 80 to 150 μm. If the thickness of the base film is 50 μm or more, the handleability is improved, and if the thickness is 300 μm or less, the flexibility (expandability) can be improved. In the case of the base film for wafers, the thickness of the base film is preferably 50 to 150 μm, more preferably 70 to 100 μm.

[0036] <Manufacturing method> The base film of the present invention is manufactured by using a resin material containing the above-mentioned homopolymer of 1-butene and a low-density polyethylene having a density of 0.93 g / cm 3 or less, and extruding and molding the resin material at a predetermined temperature by an extruder equipped with a T-die, for example. Note that the base film of the present invention may also be manufactured by a known calendar method or inflation method.

[0037] <Other forms> Various additives may be contained in the base film of the present invention. As the additives, known additives usually used for semiconductor manufacturing tapes can be used, and examples include crosslinking aids, antistatic agents, heat stabilizers, antioxidants, ultraviolet absorbers, lubricants, antiblocking agents, colorants, and the like. Note that these additives may be used alone or in combination of two or more.

[0038] In addition, examples of the crosslinking aid include triallyl isocyanurate and the like. When the base film contains a crosslinking aid, the content of the crosslinking aid in the base film is preferably 0.05 to 5 parts by mass, more preferably 1 to 3 parts by mass, based on 100 parts by mass of the resin forming the base film.

Examples

[0039] Hereinafter, the present invention will be described based on examples. It should be noted that the present invention is not limited to these examples, and these examples can be modified and changed based on the gist of the present invention, and they are not excluded from the scope of the present invention.

[0040] The materials used for producing the base film are shown below. (1) LLDPE-1: Linear low-density polyethylene, melting point: 120 °C, density: 0.913 g / cm 3 , MFR: 2.0 g / 10 min (2) LLDPE-2: Linear low-density polyethylene, melting point: 108 °C, density: 0.921 g / cm 3 , MFR: 2.5 g / 10 min (3) LLDPE-3: Linear low-density polyethylene, melting point: 93 °C, density: 0.903 g / cm 3 , MFR: 2.0 g / 10 min (4) LLDPE-4: Linear low-density polyethylene, melting point: 124 °C, density: 0.936 g / cm 3 , MFR: 2.0 g / 10 min (5) LLDPE-5: Linear low-density polyethylene, density: 0.923 g / cm 3 , MFR: 0.5 g / 10 min (manufactured by Prime Polymer Co., Ltd., trade name: Ultrex (registered trademark) 2005HC) (6) LDPE-1: Low-density polyethylene, melting point: 108 °C, density: 0.918 g / cm 3 , MFR: 7.5 g / 10 min (manufactured by Ube Maruzen PE Co., Ltd., trade name: UBE polyethylene L719) (7) LDPE-2: Low-density polyethylene, melting point: 110 °C, density: 0.922 g / cm 3, MFR: 5.0 g / 10 min (manufactured by Ube Maruzen PE Co., Ltd., product name: UBE Polyethylene F522N) (8) PP Elastomer 1: Propylene-based elastomer, density: 0.889 g / cm 3 , MFR: 8.0 g / 10 min (230 °C), polyethylene content 4% (manufactured by ExxonMobil, product name: Vistamaxx® 3588FL) (9) PP Elastomer 2: Propylene-based elastomer, density: 0.862 g / cm 3 , MFR: 3.0 g / 10 min (230 °C), polyethylene content: 16% (manufactured by ExxonMobil, product name: Vistamaxx® 6102FL) (10) Amorphous polyolefin + crystalline polypropylene (1-butene·propylene copolymer: crystalline polypropylene = 50:50): density: 0.880 g / cm 3 , MFR: 11.7 g / 10 min (manufactured by Dainichi Kasei Co., Ltd., product name: Pericon CAP350S) (11) 1-Bu: Homopolymer of 1-butene, melting point: 128 °C, density: 0.920 g / cm 3 , MFR: 0.5 g / 10 min

[0041] (Example 1) <Preparation of Base Film> First, each material shown in Table 1 was blended to prepare a resin material for Example 1 having the composition (parts by mass) shown in Table 1. Next, this resin material was extruded using a three-layer co-extrusion machine through a T-die under the conditions of a die temperature of 180 - 200 °C and a chill roll temperature of 40 °C to obtain a base film having the thickness shown in Table 1.

[0042] <Evaluation of Yield Point Presence or Absence> Using the prepared base film, a sample for measurement was obtained in accordance with JIS K7161-2:2014. Next, the obtained measurement sample was set in a tensile testing machine (manufactured by Shimadzu Corporation, product name: AG-5000A) such that the distance between the grips was 40 mm, and a tensile test was conducted at a tensile speed of 300 mm / min in an environment of 23 °C and a relative humidity of 40% in accordance with JIS K7161-2:2014.

[0043] Then, in the S-S curves (stress-strain curves) of MD and TD, those in which no yield point was confirmed during the elongation ratio from 0% to 100% (no necking occurred and uniform expansion was possible) were marked as 〇, and those in which the yield point was confirmed (necking occurred and uniform expansion was impossible) were marked as ×. The above results are shown in Table 1.

[0044] Note that the S-S curves (stress-strain curves) of MD and TD in the base film of this example are shown in FIGS. 1 to 2. As shown in FIGS. 1 to 2, it can be seen that there is no yield point in the S-S curves (stress-strain curves) of MD and TD during the elongation ratio from 0% to 100%.

[0045] <Measurement of Stress in MD and TD> Using the produced base film, a sample for measurement was obtained in accordance with JIS K7161-2:2014. Next, the obtained sample for measurement was set in a tensile testing machine (manufactured by Shimadzu Corporation, product name: AG-5000A) so that the distance between the gripping tools was 40 mm, and a tensile test was conducted at a tensile speed of 300 mm / min in an environment where the temperature was 23°C and the relative humidity was 40% in accordance with JIS K7161-2:2014.

[0046] Then, the stress at 25% elongation (25% stress) in MD and TD of the base film was measured, and the ratio of the stress in MD to the stress in TD (at 25% elongation) (that is, the stress ratio of the base film at 25% elongation) was calculated. The above results are shown in Table 1.

[0047] Similarly, the stress at 20% elongation (20% stress) and the stress at 40% elongation (40% stress) in the MD and TD of the base film were measured, and the ratio of the stress at 40% elongation to the stress at 20% elongation (i.e., the elongation rate of the base film in the MD) and the ratio of the stress at 40% elongation to the stress at 20% elongation (i.e., the elongation rate of the base film in the TD) were calculated. The above results are shown in Table 1.

[0048] <Rigidity evaluation> The rigidity of the produced base film was evaluated. More specifically, in the manufacturing process of the base film, when the unwinding of the base material is possible, it is marked as 〇 (the rigidity of the base film is excellent), and when the unwinding of the base material is unstable in the manufacturing process of the base film, it is marked as × (the rigidity of the base film is poor). The above results are shown in Table 1.

[0049] <Processing stability evaluation> The processing stability of the produced base film was evaluated. More specifically, when it is possible to suppress the adhesion of the base film to the conveying roll during the conveyance of the base film, and at the same time, it is possible to prevent blocking during the winding of the base film and thickness variation due to draw resonance during the forming of the base film, it is marked as 〇 (the processing stability of the base film is excellent). When the base film adheres to the conveying roll during the conveyance of the base film, making it difficult to convey and wind the base film, or when the thickness variation due to draw resonance during the forming of the base film is large, it is marked as × (the processing stability of the base film is poor). The above results are shown in Table 1.

[0050] (Examples 2 to 9, Comparative Examples 1 to 3) Except that the composition of the resin component was changed to the composition (parts by mass) shown in Tables 1 to 2, a base film having the thickness shown in Tables 1 to 2 was produced in the same manner as in Example 1 described above.

[0051] Then, in the same manner as in Example 1 described above, evaluation of the presence or absence of a yield point, measurement of stress in the MD and TD directions, rigidity evaluation, and process stability evaluation were performed. The above results are shown in Tables 1 to 2.

[0052] (Comparative Examples 4 to 6) First, in each of the comparative examples, each of the materials shown in Table 3 was blended to prepare a resin material for forming a surface layer and a resin material for forming an intermediate layer having the compositions (parts by mass) shown in Table 3.

[0053] Next, using a co-extrusion machine for three-layer with a T-die, the resin material for forming a surface layer and the resin material for forming an intermediate layer were simultaneously extruded and molded under the conditions of 180 to 200°C and a chill roll temperature of 40°C, to obtain a base film having a thickness shown in Table 3 (i.e., the ratio of the intermediate layer to the entire base film is 80%) and having a three-layer structure laminated in the order of surface layer / intermediate layer / surface layer.

[0054] Then, in the same manner as in Example 1 described above, evaluation of the presence or absence of a yield point, measurement of stress in the MD and TD directions, rigidity evaluation, and process stability evaluation were performed. The above results are shown in Table 3.

[0055]

Table 1

[0056]

Table 2

[0057]

Table 3

[0058] As shown in Table 1, a homopolymer of 1-butene and a density of 0.93 g / cm 3In the base films of Examples 1 to 9 containing low-density polyethylene below, where the mass ratio of the homopolymer of 1-butene to low-density polyethylene is 1-butene homopolymer:low-density polyethylene = 10:90 to 70:30, no yield point is confirmed, and it can be seen that they are excellent in uniform elongation and also excellent in rigidity and processing stability.

[0059] On the other hand, as shown in Table 2, in the base film of Comparative Example 1, the mass ratio of the homopolymer of 1-butene to low-density polyethylene is 1-butene homopolymer:low-density polyethylene = 80:20. Since the content of the 1-butene homopolymer is high, a yield point is confirmed, and in TD, the ratio of the stress (at 40% elongation) to the stress (at 20% elongation) is less than 1, and it can be seen that the uniform elongation is poor.

[0060] Also, as shown in Table 2, in the base film of Comparative Example 2, since no homopolymer of 1-butene is contained, a yield point is confirmed, the uniform elongation is poor, and it can also be seen that the processing stability is poor.

[0061] Also, as shown in Table 2, in the base film of Comparative Example 3, the density of the low-density polyethylene is greater than 0.93 g / cm 3 (it is 0.936 g / cm 3 ). Therefore, a yield point is confirmed, and in TD, the ratio of the stress (at 40% elongation) to the stress (at 20% elongation) is less than 1, and it can be seen that the uniform elongation is poor.

[0062] Also, as shown in Table 3, in the base film of Comparative Example 4, since no homopolymer of 1-butene is contained, a yield point is confirmed and the uniform elongation is poor. Also, since the ratio of the stress (at 25% elongation) in TD to the stress (at 25% elongation) in MD is greater than 1.3, it can be seen that the isotropy is poor. Also, since a low-viscosity butene copolymer is used, the thickness variation due to draw resonance becomes large when forming the base film, and it can be seen that the processing stability is poor.

[0063] Also, as shown in Table 3, in the base film of Comparative Example 5, a homopolymer of 1-butene is not contained, and since the stress (at 25% elongation) in TD is less than 5 MPa, in the manufacturing process of the base film, the unwinding of the base material becomes unstable, indicating that it lacks rigidity.

[0064] Also, as shown in Table 3, in the base film of Comparative Example 6, a homopolymer of 1-butene is not contained, and in MD and TD, the ratio of the stress (at 40% elongation) to the stress (at 20% elongation) is less than 1, so the yield point is confirmed, indicating that it lacks uniform stretchability. Also, since the stress (at 25% elongation) in MD and TD is less than 5 MPa, in the manufacturing process of the base film, the unwinding of the base material becomes unstable, indicating that it lacks rigidity. Further, since the surface of the film has high adhesiveness, when transporting the base film, the base film adheres to the transport roll, making it difficult to transport and wind up the base film, indicating that it lacks processing stability.

Industrial Applicability

[0065] As described above, the present invention is suitable for a base film for a semiconductor manufacturing tape.

Claims

1. A homopolymer of 1-butene, and The low-density polyethylene having a density of 0.93 g / cm ３ or less, and the mass ratio of the homopolymer of 1-butene to the low-density polyethylene is such that homopolymer of 1-butene:low-density polyethylene = 10:90 to 70:30, the low-density polyethylene is linear low-density polyethylene, the melt mass flow rate (MFR) of the linear low-density polyethylene is 1.0 to 6.0 g / 10 min, a base film for a semiconductor manufacturing tape, characterized in that the stress (at 25% elongation) is 5 MPa or more and 20 MPa or less.

2. The base film for a semiconductor manufacturing tape according to Claim 1, characterized in that the ratio of the stress (at 40% elongation) to the stress (at 20% elongation) is 1 or more and 2 or less.

3. The base film for a semiconductor manufacturing tape according to Claim 1 or Claim 2, characterized in that the ratio of the stress (at 25% elongation) in the MD to the stress (at 25% elongation) in the TD is 0.8 or more and 1.3 or less.

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