Adhesive sheet

Abstract

To provide an adhesive sheet provided with an adhesive layer in which generation of interlayer peeling between single layers and formation of internal cracks are both restrained.SOLUTION: An adhesive sheet including at least two single layers 11a, an organic component containing a thermoplastic component and a thermosetting component, and an inorganic filler dispersed in the organic component, wherein, in each of the single layers, a maximum value of a Hansen solubility parameter distance between the thermoplastic component and the thermosetting component is 8.5 or less, and in at least one of the single layers in the cured adhesive layer 11, the organic component is in a non-phase-separated state and the inorganic filler is dispersed in the organic component in the non-phase-separated state, or in at least one of the single layers in the cured adhesive layer, the organic component is in a phase-separated state, a dispersed phase containing more of the thermosetting component than the thermoplastic component is dispersed in a continuous phase containing more of the thermoplastic component than the thermosetting component, and the inorganic filler is dispersed in the dispersed phase.SELECTED DRAWING: Figure 1B

Description

[Technical Field]

[0001] The present invention relates to an adhesive sheet having an adhesive layer that is used, for example, when manufacturing a semiconductor device having a semiconductor integrated circuit or the like. [Background technology]

[0002] Conventionally, dicing die bond films used in the manufacture of semiconductor devices have been known. This type of dicing die bond film includes, for example, a dicing tape and a die bond sheet laminated on the dicing tape and adhered to a wafer. The dicing tape has a base layer and a pressure-sensitive adhesive layer in contact with the die bond sheet. This type of dicing die bond film is used in the manufacture of semiconductor devices, for example, as follows.

[0003] A method for manufacturing a semiconductor device generally includes a front-end process of forming a circuit surface on one side of a wafer using highly integrated electronic circuits, and a back-end process of cutting chips from the wafer with the circuit surface formed and assembling them.

[0004] The post-processing includes, for example, a fragile portion forming process in which a fragile portion is formed in the semiconductor wafer using a laser beam or the like to split the wafer (semiconductor wafer) into small chips (dies), a back-grinding process in which the surface opposite the circuit surface of the wafer where the fragile portion is formed is polished and cut, a mounting process in which the surface opposite the circuit surface of the wafer is attached to a die-bonding sheet and the semiconductor wafer is fixed to a dicing tape via the die-bonding sheet, a dicing process in which the dicing tape is stretched in the surface direction to separate the semiconductor wafer into chips (dies) using the fragile portions as boundaries and widen the gaps between adjacent chips (dies), a pick-up process in which the die-bonding sheet is peeled off from the adhesive layer to remove the chips (dies) with the die-bonding sheet attached, a die-bonding process in which the chips (dies) with the die-bonding sheet attached are attached to an adherend via the die-bonding sheet, and a curing process in which the die-bonding sheet attached to the adherend is hardened. A semiconductor integrated circuit in a semiconductor device is manufactured through, for example, these processes.

[0005] In the above-described semiconductor device manufacturing method, after the die bonding step, a relatively thick die bond sheet may be attached to the adherend so as to cover and embed the chip (die) attached to the adherend, and then a plurality of chips (dies) with die bond sheets attached thereto may be further stacked on top of the die bond sheet.

[0006] In a method for manufacturing a semiconductor device that includes a step of stacking a plurality of chips (dies) as described above, an adhesive layer that can manufacture semiconductor devices with a good yield and is used as the die bond sheet is known (for example, Patent Document 1).

[0007] Specifically, the adhesive layer (die bond sheet) described in Patent Document 1 is an adhesive layer for embedding a semiconductor element fixed on an adherend and for stacking additional semiconductor elements, and has a thickness T that is greater than the thickness T1 of the semiconductor element to be embedded, with the difference between thickness T and thickness T1 designed to be 10 μm or more and 260 μm or less. The adhesive layer described in Patent Document 1 allows the semiconductor element fixed on the adherend to be suitably embedded depending on the connection mode (wire bonding connection or flip chip connection) between the adherend and the semiconductor element. [Prior art documents] [Patent documents]

[0008] [Patent Document 1] Japanese Patent Application Laid-Open No. 2014-011257 Summary of the Invention [Problem to be solved by the invention]

[0009] A semiconductor device manufactured to include the adhesive layer (die bond sheet) as described above can be used in both low-temperature and high-temperature environments. Furthermore, the relatively thick adhesive layer described in Patent Document 1 can be produced by laminating multiple single layers. However, in adhesive layers in which multiple monolayers are laminated, peeling between adjacent monolayers can occur due to shrinkage of each monolayer in low-temperature environments, etc. Furthermore, cracks (fine tears) can occur inside the adhesive layer due to expansion of the adhesive layer in high-temperature environments, etc.

[0010] In response to this, there is a demand for an adhesive layer that suppresses both the occurrence of peeling between the single layers and the occurrence of internal cracks, but adhesive sheets equipped with such an adhesive layer have not yet been fully studied.

[0011] Therefore, an object of the present invention is to provide an adhesive sheet having an adhesive layer that suppresses both the occurrence of peeling between the single layers and the occurrence of internal cracks. [Means for solving the problem]

[0012] In order to solve the above problems, the adhesive sheet according to the present invention has: An adhesive sheet having an adhesive layer in which a plurality of monolayers are laminated, At least two adjacent monolayers each contain an organic component containing at least a thermoplastic component and a thermosetting component, and an inorganic filler dispersed in the organic component; In each of the monolayers, the maximum value of the Hansen solubility parameter distance between the thermoplastic component and the thermosetting component is 8.5 or less; In at least one of the monolayers of the adhesive layer after curing, the organic component is in a non-phase-separated state, and the inorganic filler is dispersed in the non-phase-separated organic component, or In at least one of the monolayers of the adhesive layer after curing, the organic component is in a phase-separated state, and a dispersed phase containing more of the thermosetting component than the thermoplastic component is dispersed in a continuous phase containing more of the thermoplastic component than the thermosetting component, and the inorganic filler is dispersed in the dispersed phase. [Effects of the Invention]

[0013] The adhesive layer of the adhesive sheet according to the present invention is inhibited from both peeling between the single layers and internal cracking. [Brief explanation of the drawings]

[0014] [Figure 1A] FIG. 2 is a cross-sectional view of the adhesive sheet of the present embodiment cut in the thickness direction. [Figure 1B] FIG. 2 is a cross-sectional view of the adhesive layer of the adhesive sheet of the present embodiment cut in the thickness direction. [Figure 1C] 1 is a cross-sectional view of a dicing die bond film having an adhesive layer according to the present embodiment, cut in the thickness direction. [Figure 2A] FIG. 2 is a cross-sectional view schematically showing an electron microscope image of a cross section of an example of an adhesive layer corresponding to an example. [Figure 2B] FIG. 10 is a cross-sectional view schematically showing an electron microscope image of a cross section of another example of an adhesive layer corresponding to an example. [Figure 2C] FIG. 10 is a cross-sectional view schematically showing an electron microscope image of a cross section of an example of an adhesive layer that does not correspond to an example. [Figure 3A] 3A to 3C are schematic cross-sectional views showing an example of a process for producing the adhesive sheet of the present embodiment. [Figure 3B] 3A to 3C are schematic cross-sectional views showing an example of a process for producing the adhesive sheet of the present embodiment. [Figure 3C] 3A to 3C are schematic cross-sectional views showing an example of a process for producing the adhesive sheet of the present embodiment. [Figure 3D] 3A to 3C are schematic cross-sectional views showing an example of a process for producing the adhesive sheet of the present embodiment. [Figure 3E] 3A to 3C are schematic cross-sectional views showing an example of a process for producing the adhesive sheet of the present embodiment. [Figure 4A] FIG. 2 is a cross-sectional view schematically illustrating a state before back grinding in the method for manufacturing a semiconductor device. [Figure 4B] 1A and 1B are cross-sectional views schematically illustrating back grinding in a method for manufacturing a semiconductor device. [Figure 4C] 1A and 1B are cross-sectional views schematically illustrating a stealth dicing step in a method for manufacturing a semiconductor device. [Figure 4D] 1A and 1B are cross-sectional views schematically illustrating back grinding in a method for manufacturing a semiconductor device. [Figure 5A] 1A to 1C are cross-sectional views schematically illustrating a mounting step in a method for manufacturing a semiconductor device. [Figure 5B] 1A to 1C are cross-sectional views schematically illustrating a mounting step in a method for manufacturing a semiconductor device. [Figure 5C] 10A and 10B are cross-sectional views schematically illustrating an expanding step at a low temperature in the method for manufacturing a semiconductor device. [Figure 5D] 10A and 10B are cross-sectional views schematically illustrating an expanding step at a low temperature in the method for manufacturing a semiconductor device. [Figure 5E] 10A and 10B are cross-sectional views schematically illustrating an expanding step at a low temperature in the method for manufacturing a semiconductor device. [Figure 5F] 1A to 1C are cross-sectional views schematically illustrating an expanding step at room temperature in a method for manufacturing a semiconductor device. [Figure 5G] 1A and 1B are cross-sectional views schematically illustrating an expanding step at room temperature in a method for manufacturing a semiconductor device. [Figure 5H] 1A to 1C are cross-sectional views schematically illustrating a pickup step in a method for manufacturing a semiconductor device. [Figure 6A] 1A to 1C are cross-sectional views schematically illustrating a die bonding step in a method for manufacturing a semiconductor device. [Figure 6B] FIG. 10 is a cross-sectional view schematically illustrating a state after a sealing step in the method for manufacturing a semiconductor device. [Figure 7A] 1 is a photograph showing an example of an image of a cross section of an adhesive layer observed under an electron microscope. [Figure 7B] 10 is a photograph showing another example of an image of a cross section of an adhesive layer observed under an electron microscope. [Figure 7C] 10 is a photograph showing another example of an image of a cross section of an adhesive layer observed under an electron microscope. DETAILED DESCRIPTION OF THE INVENTION

[0015] One embodiment of an adhesive sheet according to the present invention will now be described with reference to the drawings. Adhesive sheet 10 of this embodiment comprises at least adhesive layer 11, as shown in FIG. 1A, for example. Adhesive sheet 10 of this embodiment may further comprise one release liner 12 overlying one side of adhesive layer 11. Alternatively, adhesive sheet 10 of this embodiment may further comprise two release liners 12 overlying both sides of adhesive layer 11.

[0016] 1B, adhesive layer 11 of the adhesive sheet of this embodiment is formed by laminating multiple layers (single layers 11a). The number of layers (single layers 11a) constituting adhesive layer 11 may be, for example, 2 or more and 5 or less.

[0017] The adhesive layer 11 of the adhesive sheet of this embodiment is used, for example, to manufacture a semiconductor device having a semiconductor integrated circuit. In this case, the adhesive layer 11 is used, for example, as a die bond sheet for adhering a semiconductor chip or the like to an adherend or for embedding a semiconductor chip or the like.

[0018] An example in which the adhesive layer 11 of the adhesive sheet 10 of this embodiment is used as a die-bonding sheet, which is one member constituting the dicing die-bonding film 1, will be described in detail below.

[0019] As shown in Fig. 1C, the dicing die bond film 1 comprises a dicing tape 20 and an adhesive layer 11 (die bond sheet) laminated on the pressure-sensitive adhesive layer 22 of the dicing tape 20 and adhered to a semiconductor wafer. The adhesive layer 11 (die bond sheet) is to be adhered to an adherend such as a circuit board or a semiconductor chip, for example, in the manufacture of a semiconductor device having a semiconductor integrated circuit. Note that the figures are schematic diagrams and do not necessarily have the same aspect ratio as the actual product.

[0020] <Adhesive layer of adhesive sheet> The adhesive layer 11 of the adhesive sheet 10 of this embodiment has a plurality of monolayers 11a containing an organic component and an inorganic filler dispersed in the organic component, and the plurality of monolayers 11a are laminated. In at least two adjacent monolayers 11a, the organic component contains at least a thermoplastic component and a thermosetting component, and in each monolayer 11a, the maximum Hansen solubility parameter distance between the thermoplastic component and the thermosetting component is 8.5 or less. In at least one of the monolayers in the adhesive layer after curing, the organic component is in a non-phase-separated state, and the inorganic filler is dispersed in the organic component in the non-phase-separated state. Alternatively, in at least one of the monolayers of the adhesive layer after curing, the organic component is in a phase-separated state, and a dispersed phase containing more of the thermosetting component than the thermoplastic component is dispersed in a continuous phase containing more of the thermoplastic component than the thermosetting component, and the inorganic filler is dispersed in the dispersed phase.

[0021] The adhesive layer 11 contains at least a thermoplastic component and a thermosetting component as organic components, and further contains an inorganic filler. The thermoplastic component contains, for example, an acrylic polymer, which will be described in detail later. The thermosetting component contains, for example, a thermosetting resin and a phenolic resin (polymeric curing agent), which will be described in detail later.

[0022] In this specification, it is sufficient that at least one of two adjacent monolayers 11a (among a plurality of pairs of monolayers) in the adhesive layer 11 contains the above-described components. Similarly, it is sufficient that at least one of the adjacent monolayers 11a satisfies the Hansen solubility parameter distance requirement described below. On the other hand, it is sufficient that at least one of the monolayers 11a in the adhesive layer 11 satisfies the requirement (A) or (B) (referring to the dispersion state of the inorganic filler) described in detail below. It is preferable that all the monolayers 11a of the adhesive layer 11 each contain the components as described above, and that all the monolayers 11a satisfy the Hansen solubility parameter distance requirement and the requirement (A) or (B) described in detail below.

[0023] The maximum value of the Hansen Solubility Parameter distance between the thermoplastic component and the thermosetting component is 8.5 or less. The maximum value of the HSP distance is the value when the HSP distance between any one of the thermoplastic components and any one of the thermosetting components is the maximum. The minimum value of the Hansen solubility parameter distance may be 0.5 or more. Hereinafter, the Hansen solubility parameter distance may be simply referred to as the HSP distance.

[0024] The above HSP distances are calculated as follows. For example, the above HSP distances can be calculated using the computer software "HSPiP (Hansen Solubility Parameters in Practice) ver. 4," which is available on the website. The Hansen solubility parameter (HSP) is a parameter obtained by dividing the Hildebrand solubility parameter into three components: a dispersion term, a polar term, and a hydrogen bonding term. The dispersion term, polar term, and elementary bonding term can be expressed in three-dimensional coordinates. The Hansen solubility parameter of any of the thermoplastic components is calculated using the three-dimensional coordinates (δ dA , δ pA , δ hA ) and the Hansen solubility parameter of any of the thermosetting components is expressed as a three-dimensional coordinate (δ dD , δ pD , δ hD ), the Hansen solubility parameter distance (HSP distance) Ra is calculated according to the following formula (1):

[0025]

number

[0026] The HSP distance is one indicator of the degree of mutual solubility (compatibility) between the thermoplastic component and the thermosetting component. When the thermoplastic component and the thermosetting component each contain components that result in a smaller maximum HSP distance (when their three-dimensional coordinates are closer to each other), their compatibility with each other can be said to be high. On the other hand, when the opposite is true, their compatibility with each other can be said to be low. In other words, the smaller the maximum value of the HSP distance Ra calculated according to the above formula (1), the higher the compatibility between the thermoplastic component and the thermosetting component, and the larger the maximum value of the HSP distance Ra, the lower the compatibility between the thermoplastic component and the thermosetting component.

[0027] The dispersion term δ of one component (e.g., acrylic polymer) contained in the thermoplastic component dA , polarity term δ pA , and the hydrogen bond term δ hA , and the dispersion term δ of one component (e.g., epoxy resin or phenolic resin) included in the thermosetting component. dD , polarity term δ pD , and the hydrogen bond term δ hD can be derived, for example, by the following simulation. (1) Create a Smiles (simplified molecular input line entry system) notation for the polymer unit obtained by polymerizing each monomer used to polymerize each polymer compound. For example, if a polymer unit obtained by polymerizing a monomer is a polymer unit obtained by polymerizing styrene, it is expressed as XCC(C1=CC=CC=C1)X in Smiles notation. The Xs at both ends are dummy atoms. (2) Using the Windows software "HSPiP ver. 4" (the main program and license file can be purchased by visiting https: / / www.hansen-solubility.com / ), calculate the dispersion term, polar term, and hydrogen bond term for each polymer unit. Furthermore, the molar ratio of each polymer unit in each polymer compound contained in the thermoplastic component and the thermosetting component is calculated. (3) For each polymer compound contained in the thermoplastic component and the thermosetting component, the dispersion term, polarity term, and hydrogen bond term for each polymer unit are multiplied by the molar ratio of each polymer unit, and then these are added together. As a result, a dispersion term, a polar term, and a hydrogen bond term are obtained for each polymer compound that is a polymerization reaction product. That is, for each polymer compound contained in the thermoplastic component, the dispersion term δ dA , polarity term δ pA , and the hydrogen bond term δ hA and for each polymer compound contained in the thermosetting component, the dispersion term δ dD , polarity term δ pD , and the hydrogen bond term δ hD get.

[0028] When the polymer units constituting each polymer compound are not clear, the molar ratio of each polymer unit in each polymer compound can be determined as follows. Specifically, a sample taken from each monolayer of the adhesive layer 11 is used as an analytical sample, and the analytical sample is subjected to high-temperature methanol decomposition treatment (hydrolysis treatment).The resulting decomposition product is then subjected to GC / MS analysis, and either total nitrogen (TN) analysis or CHN elemental analysis is performed on the analytical sample that has not been decomposed, allowing the identification of each polymer unit in each polymer compound contained in the thermoplastic component. If the amount of nitrogen contained in the analytical sample is less than 0.5% by mass, the amount of nitrogen can be quantified by TN analysis, and if the amount of nitrogen contained in the analytical sample is 0.5% by mass or more, the amount of nitrogen can be quantified by CHN elemental analysis. Similarly, each polymer unit in each polymer compound contained in the thermosetting component can be estimated. The combination of the above GC / MS analysis and TN analysis is particularly suitable when the polymer compounds contained in the thermoplastic component and the thermosetting component are composed of AN (acrylonitrile), AA (acrylic acid), EA (ethyl acrylate), and BA (butyl acrylate). As described above, when the polymer compounds contained in the thermoplastic component are composed of AN, AA, EA, and BA, GC / MS analysis can be performed by taking 10 mg of a sample from each single layer of the adhesive layer 11 as a GC / MS analysis sample, and subjecting the GC / MS analysis sample to high-temperature methanol decomposition (hydrolysis) to obtain a decomposition product, using the conditions shown in Table A. In the GC / MS analysis, the amounts of ethanol and butanol are quantified. In addition, TN analysis can be performed by placing a few mg of TN analysis sample taken from each single layer of the adhesive layer 11 on a ceramic board, weighing it on a microbalance, and then employing the conditions shown in Table B for the TN analysis sample. Furthermore, when quantifying the amount of nitrogen by CHN elemental analysis instead of TN analysis, the CHN elemental analysis can be performed by taking a sample for CHN elemental analysis in an amount of several mg to several tens of mg from each single layer of the adhesive layer 11, sealing it in tin foil, and then adopting the conditions shown in Table C for the CHN elemental analysis sample. Since the analysis method varies depending on the composition of the polymer, it is not necessary to perform the analysis of the analysis sample collected from each single layer of the adhesive layer 11 by a combination of GC / MS analysis and TN analysis, or a combination of GC / MS analysis and CHN elemental analysis. 13 C-NMR analysis, 1 This can be carried out by H-NMR analysis, FT-IR analysis, etc.

[0029] [Table A]

[0030] [Table B]

[0031] [Table C]

[0032] The dispersion term δ for each polymer compound contained in the thermoplastic component obtained as described above dA , polarity term δ pA , and the hydrogen bond term δ hA is substituted into the above formula (1), and the dispersion term δ dD , polarity term δ pD , and the hydrogen bond term δ hD By substituting into the above formula (1), the Hansen solubility parameter distance Ra can be calculated.

[0033] The adhesion between two adjacent monolayers can be evaluated using the Hansen Solubility Parameter distance (HSP distance) Ra between the polymer compounds contained in the thermoplastic and thermosetting components. The smaller the maximum Ra value, the stronger the adhesion between the two adjacent monolayers, and the larger the maximum Ra value, the weaker the adhesion between the two adjacent monolayers. It is preferable that the difference in the maximum HSP distance between two adjacent monolayers is as small as possible.

[0034] Since the maximum HSP distance between any two adjacent monolayers is 8.5 or less as described above, the affinity between the thermoplastic and thermosetting components contained in each monolayer is relatively good. Therefore, the component composition of each monolayer, particularly the surface portion (the surface portion in contact with the outside air or the surface portion in contact with the release liner), is prevented from differing from the component composition of the interior. In other words, the component composition is prevented from varying between the front portion and the interior of each monolayer. Therefore, delamination between the two adjacent monolayers can be prevented.

[0035] After curing, a part of the adhesive layer 11 of the adhesive sheet of this embodiment (a part of a cross section of a single layer cut in the thickness direction) was observed under an electron microscope under the following conditions, and the image was as follows: (A) In at least one of the monolayers of the adhesive layer after curing, the organic component is in a non-phase-separated state, and the inorganic filler is dispersed in the organic component in the non-phase-separated state, or (B) In at least one of the monolayers of the adhesive layer after curing, the organic component is in a phase-separated state, and a dispersed phase containing a larger amount of the thermosetting component than the thermoplastic component is dispersed in a continuous phase containing a larger amount of the thermoplastic component than the thermosetting component, and the inorganic filler is dispersed in the dispersed phase. In such a case, the content of the thermoplastic component in the continuous phase is higher than the content of the thermosetting component, and the content of the thermosetting component in the dispersed phase is higher than the content of the thermoplastic component. The higher the content of thermoplastic components, the fewer secondary electrons generated by the electron gun, making the observed image appear darker. On the other hand, the higher the content of thermosetting components, the more secondary electrons are generated, making the observed image appear lighter.

[0036] [Electron microscope observation conditions] Preparation of specimens for observation: The procedure is resin embedding, mechanical polishing, ion polishing (IP) processing, conductive treatment, and observation. Electronic staining method: No staining was performed Equipment: Field emission scanning electron microscope (e.g., Hitachi High-Technologies Corporation S4800) Acceleration voltage: 3 kV Observed image: Secondary electron image Magnification: 20,000x Observation area: Approximately square area with at least 5 μm on each side

[0037] By visually checking the above observed image, it can be determined that it is either (A) or (B) above. In the case of (A) above, the inorganic filler can be easily recognized because its outer edge is circular or elliptical. When viewing the portion other than the inorganic filler in the observed image, almost no difference in shade is observed. In other words, the difference in shade of the portion other than the inorganic filler is smaller than the difference in shade of the portion other than the inorganic filler in the cases of (B) or (C) below. Therefore, the portion corresponding to the continuous phase in a non-phase-separated state has almost no difference in shade and appears to be of uniform shade. The presence of each particle is observed within the continuous phase, which appears to be of nearly uniform shade (see, for example, Figures 2A and 7A). In the case of (B) above, the inorganic filler can also be easily recognized because its outer edge is circular or elliptical. When viewing the areas other than the inorganic filler in the observed image, darker and lighter areas are observed. The areas surrounding each particle appear lighter, and the areas other than those surrounding each particle appear darker. The areas corresponding to the continuous phase, which contains more thermoplastic components than thermosetting components, appear darker. The areas corresponding to the dispersed phase, which contains more thermosetting components than thermoplastic components, appear lighter. The presence of each particle is observed within the lighter areas corresponding to the dispersed phase (see, for example, Figures 2B and 7B). On the other hand, in cases other than (A) and (B) (for example, case (C)), the inorganic filler can be easily recognized because its outer edge is circular or elliptical. When viewing the parts other than the inorganic filler in the observed image, darker and lighter parts are observed. The parts surrounding each particle appear darker, and the parts other than the parts surrounding each particle appear lighter. The parts corresponding to the dispersed phase, which contains more thermoplastic components than thermosetting components, appear darker. The parts corresponding to the continuous phase, which contains more thermosetting components than thermoplastic components, appear lighter. The presence of each particle is observed within the dark parts corresponding to the dispersed phase (see, for example, Figures 2C and 7C).

[0038] To achieve the above state (A), for example, the affinity between the thermoplastic component and the thermosetting component contained in the adhesive layer 11 is increased. Specifically, the HSP value between the thermoplastic component and the thermosetting component is reduced. To achieve the above state (B), for example, the affinity between the thermoplastic component and the inorganic filler contained in the adhesive layer 11 is reduced, or the affinity between the thermosetting component and the inorganic filler is increased. Specifically, the polarity of the acrylic polymer is increased.

[0039] In the case of the above-mentioned state (A), the inorganic filler is dispersed in a continuous phase containing both a thermosetting component and a thermoplastic component. Even if the inorganic filler is present in the continuous phase (organic component), since the continuous phase contains a thermosetting component, it is thought that the occurrence of cracks originating from the interface between the organic component and the inorganic filler is suppressed for the same reason as above. In the case of the above state (B), the inorganic filler is present (dispersed) in a dispersed phase containing a large amount of the thermosetting component. Although the thermal expansion coefficients of the organic component and the inorganic filler are significantly different, the cohesive force of the cured thermosetting component is relatively high. Therefore, even if the inorganic filler is present in the organic component of the dispersed phase containing a large amount of the thermosetting component, it is thought that the occurrence of cracks originating from the interface between the organic component and the inorganic filler is suppressed. In contrast, in cases other than (A) and (B), for example, when an inorganic filler is present in a continuous phase containing a large amount of thermoplastic components, the cohesive force of the thermoplastic components is relatively low, and it is thought that cracks are more likely to occur at the interface between the organic components in the continuous phase containing a large amount of thermoplastic components and the inorganic filler. The semiconductor device includes a semiconductor chip and the like bonded to the adhesive layer 11, and can be used in both high-temperature and low-temperature environments. Because the hardened adhesive layer 11 is used at high and low temperatures, it may be prone to internal cracks due to the difference in thermal expansion coefficients described above.

[0040] The storage modulus of the adhesive layer 11 at 85°C after curing is preferably 500 MPa or more, more preferably 1200 MPa or more. The storage modulus of the adhesive layer 11 at 85°C is preferably 3000 MPa or less, more preferably 1700 MPa or less. When the storage modulus is 500 MPa or more, the cohesive force inside the adhesive layer 11 becomes higher, and when the storage modulus is 3000 MPa or less, the stress relaxation property of the adhesive layer 11 can be further improved. Therefore, the occurrence of cracks inside the adhesive layer 11 can be further suppressed. The above "after curing" refers to the state after the adhesive layer 11 has been subjected to a heat treatment at least at 140°C for 2 hours and then a further heat treatment at 175°C for 1 hour.

[0041] The storage modulus can be reduced, for example, by increasing the total proportion of the thermoplastic resin and thermosetting resin in the adhesive layer 11 or by reducing the content of inorganic filler in the adhesive layer 11. On the other hand, the storage modulus can be increased, for example, by reducing the total proportion of the thermoplastic resin and thermosetting resin in the adhesive layer 11 or by increasing the content of inorganic filler in the adhesive layer 11.

[0042] The storage modulus is measured under the following conditions. Measurement equipment: Dynamic viscoelasticity measuring equipment For example, the "RSA-III" manufactured by Rheometrics Scientific (TA Instruments) Measurement sample: 200 μm thick (prepared by laminating each layer that makes up the adhesive layer appropriately) Test piece: 10mm wide, 40mm long strip, initial chuck distance 22.5mm Measurement mode: Tensile mode Frequency 10Hz, heating rate 10℃ / min, distortion 0.1% Measurement temperature range: 0℃ to 280℃ -Read the tensile storage modulus E' [MPa] at 85℃

[0043] The adhesive layer 11 preferably has a melt viscosity of 1000 Pa·s or more, and more preferably 2000 Pa·s or more, at 120°C. The adhesive layer 11 preferably has a melt viscosity of 8000 Pa·s or less, and more preferably 4000 Pa·s or less, at 120°C. By having the values ​​in the above numerical ranges, the adhesive layer 11 has better wettability, and can therefore be better bonded to the adherend.

[0044] The melt viscosity can be increased, for example, by increasing the proportion of thermoplastic resin in the adhesive layer 11 or by increasing the content of inorganic filler in the adhesive layer 11. On the other hand, the melt viscosity can be decreased, for example, by decreasing the proportion of thermoplastic resin in the adhesive layer 11 or by decreasing the content of inorganic filler in the adhesive layer 11.

[0045] The melt viscosity is measured under the following conditions. Measurement equipment: Dynamic viscoelasticity measuring equipment For example, the "HAAKE MARS III" manufactured by Thermo Scientific Measurement sample: 360 μm thick (prepared by laminating each layer that makes up the adhesive layer appropriately) Test piece: 8 mm diameter disc (punched from the above measurement sample) Measurement mode: Shear mode (gap 250 μm) Frequency 1Hz, heating rate 10℃ / min, distortion 5% Measurement temperature range: 80℃ to 160℃ ·Read the complex viscosity [Pa·s] at 120℃

[0046] In this embodiment, the thermoplastic component includes an acrylic polymer, which is a polymer compound obtained by polymerizing at least a (meth)acrylate monomer [a (meth)acrylic acid ester monomer]. In this specification, the term "(meth)acrylic acid" refers to at least one of methacrylic acid and acrylic acid, and the term "(meth)acrylate" refers to at least one of methacrylate (methacrylic acid ester) and acrylate (acrylic acid ester).

[0047] In each monolayer (adjacent monolayer) of the adhesive layer 11, the proportion of the thermoplastic component (particularly the proportion of the acrylic polymer) in the total amount of organic components is preferably 15% by mass or more, and more preferably 20% by mass or more. When the proportion of the thermoplastic component (particularly the acrylic polymer) is 15% by mass or more, the stress relaxation properties of the adhesive layer 11 can be further improved. The proportion of the thermoplastic component (particularly the proportion of the acrylic polymer) is preferably 35% by mass or less, and more preferably 30% by mass or less. When the proportion of the thermoplastic component (particularly the acrylic polymer) is 35% by mass or less, the cohesive force inside the adhesive layer 11 can be further increased. Therefore, the occurrence of cracks inside the adhesive layer 11 can be further suppressed.

[0048] In the above acrylic polymer, it is preferable that the mass proportion of the structural unit of alkyl (meth)acrylate is the highest. Examples of the alkyl (meth)acrylate include C2 to C8 alkyl (meth)acrylate, and preferably C2 to C4 alkyl (meth)acrylate. Note that the notation C2 in the above C2 to C8 alkyl (meth)acrylate indicates the number of carbon atoms in the alkyl portion (hydrocarbon portion) of the alkyl (meth)acrylate. Such alkyl portion is usually a saturated hydrocarbon. For example, the notation C2 to C8 indicates a carbon number of 2 to 8. The same applies hereinafter.

[0049] The acrylic polymer may further contain a structural unit derived from a glycidyl group-containing monomer in addition to the structural unit derived from the alkyl(meth)acrylate monomer. In addition to the constituent units derived from alkyl (meth)acrylate monomers, the acrylic polymer may further contain constituent units derived from, for example, a carboxy group-containing monomer, an acid anhydride monomer, a hydroxy group-containing monomer, a sulfonic acid group-containing monomer, a phosphoric acid group-containing monomer, a polar functional group-containing monomer such as acrylamide or acrylonitrile, or various other polyfunctional monomers.

[0050] The acrylic polymer is preferably a copolymer of at least an alkyl(meth)acrylate, particularly an alkyl(meth)acrylate having an alkyl moiety with 8 or less carbon atoms, and a carboxyl group- or hydroxyl-containing (meth)acrylate.

[0051] When the acrylic polymer has a glycidyl group, a carboxy group, a hydroxy group, or the like in the molecule, it may have the carboxy group, hydroxy group, or the like in a side chain, specifically, the carboxy group, hydroxy group, or the like at the end of the side chain.

[0052] The mass average molecular weight Mw of the acrylic polymer may be 500,000 or more, or 600,000 or more, and may be 1,500,000 or less, or 1,300,000 or less. When the mass average molecular weight of the acrylic polymer is 500,000 or more, the cohesive force of the adhesive layer 11 can be increased in the die bonding step (described in detail later), and the adhesive strength of the adhesive layer 11 can be increased. Furthermore, when the mass average molecular weight Mw of the acrylic polymer is 1,500,000 or less, the wettability of the adhesive layer 11 can be increased in the die bonding step (described in detail later), and the adhesive strength of the adhesive layer 11 can be increased.

[0053] When the acrylic polymer has a carboxy group in the molecule, the acid value of the acrylic polymer may be 5 mgKOH / g or more and 40 mgKOH / g or less, as measured by potentiometric titration according to JIS K2501:2003.

[0054] The acrylic polymers may be commercially available products, or may be synthesized by carrying out a polymerization reaction using an acrylic monomer such as an alkyl (meth)acrylate monomer by a general method.

[0055] In this embodiment, the adhesive layer 11 contains, for example, a thermosetting resin as the thermosetting component.

[0056] Examples of thermosetting resins include epoxy resins, phenolic resins, amino resins, unsaturated polyester resins, polyurethane resins, silicone resins, and thermosetting polyimide resins. Only one type of thermosetting resin may be used, or two or more types may be used. The thermosetting resin may contain, for example, at least one of an epoxy resin and a phenolic resin. The thermosetting resin preferably contains both an epoxy resin and a phenolic resin.

[0057] Examples of the epoxy resin include bisphenol A type, bisphenol F type, bisphenol S type, brominated bisphenol A type, hydrogenated bisphenol A type, bisphenol AF type, biphenyl type, naphthalene type, fluorene type, phenol novolac type, orthocresol novolac type, trishydroxyphenylmethane type (trisphenolmethane type), tetraphenylolethane type, hydantoin type, trisglycidyl isocyanurate type, and glycidylamine type epoxy resins. The epoxy equivalent weight [g / eq] of the epoxy resin may be, for example, 90 or more and 280 or less. The epoxy equivalent weight [g / eq] of the epoxy resin may be 220 or less.

[0058] The phenolic resin can act as a curing agent for the epoxy resin. The hydroxyl group of the phenolic resin can crosslink with the glycidyl group, so the epoxy resin and the phenolic resin can crosslink.

[0059] Examples of phenolic resins include novolac type phenolic resins, resol type phenolic resins, and polyoxystyrenes such as polyparaoxystyrene. Examples of novolac type phenolic resins include phenol novolac resins, phenol aralkyl resins (such as biphenyl aralkyl type resin phenolic resins), cresol novolac resins, tert-butylphenol novolac resins, nonylphenol novolac resins, and phenol xylylene resins. The hydroxyl group equivalent [g / eq] of the phenolic resin may be, for example, 100 or more and 250 or less. As the phenolic resin, a biphenyl aralkyl type phenolic resin having a relatively large hydroxyl group equivalent is preferred, since the elastic modulus of the adhesive layer 11 can be appropriately reduced. As the phenolic resin, only one kind or two or more kinds may be employed.

[0060] The adhesive layer 11 may contain a thermoplastic resin other than the acrylic polymer. Examples of the thermoplastic resin other than the acrylic polymer include natural rubber, butyl rubber, isoprene rubber, chloroprene rubber, ethylene-vinyl acetate copolymer, ethylene-acrylic acid copolymer, polybutadiene resin, polycarbonate resin, thermoplastic polyimide resin, polyamide resin such as 6-polyamide resin and 6,6-polyamide resin, phenoxy resin, saturated polyester resin such as PET and PBT, polyamideimide resin, and fluororesin. As the thermoplastic resin, one kind alone or two or more kinds may be adopted.

[0061] In this embodiment, the adhesive layer 11 contains an inorganic filler. By changing the amount of inorganic filler in the adhesive layer 11, the elasticity and viscosity of the adhesive layer 11 can be more easily adjusted, and the physical properties of the adhesive layer 11, such as electrical conductivity, thermal conductivity, and elastic modulus, can also be adjusted.

[0062] Examples of inorganic fillers include fillers containing aluminum hydroxide, magnesium hydroxide, calcium carbonate, magnesium carbonate, calcium silicate, magnesium silicate, calcium oxide, magnesium oxide, aluminum oxide, aluminum nitride, boron nitride, and silica such as crystalline silica and amorphous silica. Examples of inorganic filler materials include simple metals such as aluminum, gold, silver, copper, and nickel, as well as alloys. The inorganic filler may be aluminum borate whiskers, amorphous carbon black, graphite, or the like. The inorganic filler may have various shapes such as spherical, acicular, and flake-like. Only one or more of the above inorganic fillers may be used.

[0063] As the inorganic filler, silica filler is preferred, which has the advantage that the -OH groups present on the surface of the silica particles and the epoxy groups of the epoxy resin react easily during the curing treatment, thereby allowing the adhesive layer 11 to be cured more sufficiently.

[0064] The inorganic filler may have an average particle size (average particle size of primary particles) of, for example, 100 nm or more and 1 μm or less. The inorganic filler preferably has an average particle size of 200 nm or more, more preferably 300 nm or more. The inorganic filler preferably has an average particle size of 850 nm or less, more preferably 700 nm or less.

[0065] The adhesive layer 11 preferably contains 25 parts by mass or more, more preferably 30 parts by mass or more, of the thermoplastic component per 100 parts by mass of the thermosetting component. The adhesive layer 11 preferably contains 70 parts by mass or less, more preferably 60 parts by mass or less, even more preferably 50 parts by mass or less, and even more preferably 40 parts by mass or less, of the thermoplastic component per 100 parts by mass of the thermosetting component. By keeping the content within these numerical ranges, the adhesive layer 11 after curing can have appropriate stress relaxation properties and cohesive strength. Therefore, the occurrence of cracks in the adhesive layer 11 is further suppressed.

[0066] The adhesive layer 11 contains preferably 40 parts by mass or more, more preferably 50 parts by mass or more, of inorganic filler per 100 parts by mass of organic components (thermoplastic components and thermosetting components). The adhesive layer 11 contains preferably 150 parts by mass or less, more preferably 130 parts by mass or less, of inorganic filler per 100 parts by mass of organic components (thermoplastic components and thermosetting components). By keeping the content within this range, the wettability of the adhesive layer 11 is further improved, and the adhesive layer 11 can have stronger adhesive strength.

[0067] In the thermosetting component contained in the adhesive layer 11, the ratio of phenolic resin to 100 parts by mass of epoxy resin is preferably 60 parts by mass or more, more preferably 80 parts by mass or more. The ratio is preferably 140 parts by mass or less, more preferably 120 parts by mass or less. By keeping the ratio within this range, the adhesive layer 11 after curing can have appropriate stress relaxation properties and cohesive strength. Therefore, the occurrence of cracks in the adhesive layer 11 is further suppressed.

[0068] The adhesive layer 11 preferably contains 10% by mass or more and 20% by mass or less of a thermoplastic component (particularly the acrylic polymer). When the adhesive layer 11 contains a larger amount of the thermoplastic component (particularly the acrylic polymer), the adhesive layer 11 after curing can have appropriate stress relaxation properties and cohesive strength, and the occurrence of cracks in the adhesive layer 11 can be further suppressed. On the other hand, when the adhesive layer 11 contains a smaller amount of the thermoplastic resin (particularly the acrylic polymer), the adhesive layer 11 after curing can have higher cohesive strength, and the reliability of the adhesive layer 11 can be more fully ensured.

[0069] The adhesive layer 11 preferably contains 20% by mass or more and 50% by mass or less of a thermosetting component (particularly the above-mentioned epoxy resin and phenolic resin). When the adhesive layer 11 contains a larger amount of the thermosetting component, the adhesive layer 11 after curing can have a higher cohesive strength, and therefore the reliability of the adhesive layer 11 can be more fully ensured. On the other hand, when the adhesive layer 11 contains a smaller amount of the thermosetting component, the stress relaxation property of the adhesive layer 11 can be further improved, and therefore the reliability of the adhesive layer 11 can be more fully ensured.

[0070] The content of the inorganic filler in each monolayer (adjacent monolayer) of the adhesive layer 11 is preferably 30% by mass or more, more preferably 35% by mass or more, and is preferably 60% by mass or less, more preferably 55% by mass or less.

[0071] The adhesive layer 11 may contain other components as needed, such as a curing catalyst, a flame retardant, a silane coupling agent, an ion trapping agent, and a dye. Each of the monolayers (adjacent monolayers) of the adhesive layer 11 preferably contains a urea catalyst as a curing catalyst, which can make the portion of the adhesive layer 11 other than the inorganic filler more uniform. Examples of the flame retardant include antimony trioxide, antimony pentoxide, and brominated epoxy resin. Examples of the silane coupling agent include β-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, γ-glycidoxypropyltrimethoxysilane, and γ-glycidoxypropylmethyldiethoxysilane. Examples of the ion trapping agent include hydrotalcites, bismuth hydroxide, and benzotriazole. As the other additives, only one kind or two or more kinds may be employed.

[0072] The adhesive layer 11 preferably contains the above-mentioned acrylic polymer, epoxy resin, phenol resin, and silica filler, in that the elasticity and viscosity can be easily adjusted.

[0073] The thickness of the adhesive layer 11 is not particularly limited, but is, for example, 1 μm or more and 200 μm or less. Note that this thickness is the thickness of the adhesive layer 11 in which single layers are laminated (total thickness of the laminate of single layers). When the adhesive layer 11 is used in a so-called film over die (FoD) application, the thickness of the adhesive layer 11 may be 100 μm or more and 150 μm or less. In this case, the thickness of each monolayer constituting the adhesive layer 11 may be 3 μm or more, 5 μm or more, or 7 μm or more. The thickness of each monolayer may be 50 μm or less, or 40 μm or less.

[0074] Next, a method for producing the adhesive sheet of this embodiment will be described.

[0075] The adhesive sheet of this embodiment can be produced, for example, by preparing a composition for forming an adhesive layer and forming an adhesive layer from such a composition.

[0076] In preparing the composition, for example, the thermoplastic component, thermosetting component, inorganic filler, solvent, and other additives as needed are mixed to prepare the composition. The viscosity of the composition can be adjusted by changing the amount of solvent. Note that commercially available products can be used as the thermoplastic component, thermosetting component, and inorganic filler.

[0077] To form the adhesive layer, for example, the composition prepared as described above is applied to a release liner. The application method is not particularly limited, and general application methods such as roll coating, screen coating, and gravure coating are used. Next, if necessary, the applied composition is solidified by a solvent removal treatment or a curing treatment to form an adhesive layer (single layer) superimposed on the release liner.

[0078] Specifically, when forming the adhesive layer, the formed monolayers can be laminated, for example, as shown in Figures 3A to 3E. More specifically, when laminating three monolayers, for example, three laminates each consisting of a release liner and a monolayer are prepared. First, as shown in Figures 3A to 3C, two laminates are bonded together so that the monolayers of the two laminates overlap, and one of the release liners is removed. Next, as shown in Figures 3D and 3E, a monolayer of a third laminate is placed on top of the two laminated monolayers, and then one of the release liners is removed.

[0079] Next, we will explain a dicing die bond film having the above-mentioned adhesive layer 11. The above-mentioned adhesive layer 11 in the dicing die bond film is used as a so-called die bond sheet. Such a dicing die bond film is used, for example, when manufacturing a semiconductor device.

[0080] <Dicing die bond film> The dicing die bond film 1 includes the above-mentioned adhesive layer 11 and a dicing tape 20 bonded to the adhesive layer 11. The dicing tape 20 has a base layer 21 and a pressure-sensitive adhesive layer 22 overlapping the base layer 21. The above-mentioned adhesive layer 11 can function as a so-called die bond sheet.

[0081] When the dicing die bond film 1 is used, the pressure-sensitive adhesive layer 22 is cured by irradiation with active energy rays (e.g., ultraviolet rays). Specifically, in a state where the adhesive layer 11, having a semiconductor wafer bonded to one surface thereof, and the pressure-sensitive adhesive layer 22, having been attached to the other surface of the adhesive layer 11, are laminated together, ultraviolet rays or the like are irradiated onto at least the pressure-sensitive adhesive layer 22. For example, ultraviolet rays or the like are irradiated from the side where the base layer 21 is disposed, and the ultraviolet rays or the like reach the pressure-sensitive adhesive layer 22 after passing through the base layer 21. The pressure-sensitive adhesive layer 22 is cured by irradiation with ultraviolet rays or the like. Since the adhesive layer 22 hardens after irradiation, the adhesive strength of the adhesive layer 22 can be reduced, and therefore the adhesive layer 11 to which the semiconductor wafer is adhered can be relatively easily peeled off from the adhesive layer 22 after irradiation.

[0082] (dicing tape) The dicing tape 20 is usually a long sheet and is stored in a rolled state until it is used. The dicing die bond film 1 of this embodiment is stretched on an annular frame having an inner diameter slightly larger than the silicon wafer to be cut, and is used after being cut.

[0083] The base layer 21 may be a single layer, or may be made up of multiple layers (for example, three layers). The thickness (total thickness) of the base layer 21 may be 80 μm or more and 150 μm or less.

[0084] Each layer of the base material layer 21 is, for example, a metal foil, a fiber sheet such as paper or cloth, a rubber sheet, or a resin film.

[0085] The surface of the base layer 21 may be subjected to a surface treatment to enhance adhesion to the pressure-sensitive adhesive layer 22. Examples of surface treatments that can be used include oxidation treatments using chemical or physical methods such as corona treatment, antistatic treatment, chromic acid treatment, ozone exposure, flame exposure, high-voltage shock exposure, and ionizing radiation treatment. In addition, the base layer 21 may be subjected to a coating treatment using a coating agent such as an anchor coating agent, a primer, an antistatic agent, or an adhesive.

[0086] The back side of the base material layer 21 (the side on which the adhesive layer 22 is not overlapped) may be subjected to a release treatment using a release agent (release agent) such as a silicone-based resin or a fluorine-based resin to impart releasability. The base layer 21 is preferably a light-transmitting (ultraviolet-transmitting) resin film or the like, since it allows active energy rays such as ultraviolet rays to be applied to the pressure-sensitive adhesive layer 22 from the back side.

[0087] The adhesive layer 22 contains, for example, an acrylic resin, an isocyanate compound, and a polymerization initiator. The adhesive layer 22 may have a thickness of 5 μm or more and 40 μm or less. The shape and size of the adhesive layer 22 are usually the same as the shape and size of the base layer 21.

[0088] Common dicing tapes are commercially available. For example, the adhesive layer 11 is attached to the pressure-sensitive adhesive layer 22 of a commercially available dicing tape 20, and the adhesive layer 11 and the dicing tape 20 are overlapped. This allows the production of a dicing die bond film 1 including the dicing tape 20 and the adhesive layer 11 (die bond sheet).

[0089] The dicing die bond film 1 manufactured as described above is used, for example, as an auxiliary tool for manufacturing a semiconductor device having a semiconductor integrated circuit. A specific example of its use will be described below.

[0090] <Method of using dicing die bond film when manufacturing semiconductor devices> In a manufacturing method of a semiconductor device, generally, chips are cut out from a semiconductor wafer on which a circuit surface is formed and then assembled. At this time, the dicing die bond film of this embodiment is used as a manufacturing auxiliary tool.

[0091] A typical method for manufacturing a semiconductor device includes a process of cutting out chips from a semiconductor wafer on which a circuit surface is formed, and assembling the chips. This process includes, for example, a stealth dicing process in which a weakened portion is formed inside the semiconductor wafer by laser light to prepare for processing the semiconductor wafer into chips (dies) by a fracturing process; a mounting process in which one surface of the semiconductor wafer (for example, the surface opposite to the circuit surface) is attached to an adhesive layer 11 (die bond sheet) and the semiconductor wafer is fixed to the dicing tape 20; an expanding process in which the dicing tape 20 is stretched to fractur e the semiconductor wafer and adhesive layer 11 (die bond sheet) and widen the gap between the chips; and a bonding process in which the adhesive layer 11 (die bond sheet) and the adhesive are bonded to each other. The process includes a pickup step in which the semiconductor chip (die) is removed with a small piece of adhesive layer 11 (die bond sheet) attached by peeling it off from the adhesive layer 22, a die bonding step in which the adhesive layer 11 (die bond sheet) attached to the semiconductor chip (die) is bonded to an adherend, a curing step in which the adhesive layer 11 (die bond sheet) attached to the adherend is hardened, a wire bonding step in which electrodes of the electronic circuit in the semiconductor chip (die) are electrically connected to the adherend with wires, and an encapsulation step in which the semiconductor chip (die) and wires on the adherend are encapsulated with a thermosetting resin. When any of these steps is performed, at least a portion of the dicing tape (dicing die bond film) of this embodiment is used as a manufacturing aid.

[0092] Before the stealth dicing process, as shown in Figures 4A and 4B, for example, a backgrinding tape G is attached to the circuit surface of the semiconductor wafer W (see Figure 4A). With the backgrinding tape G attached, the semiconductor wafer W is subjected to a grinding process (pre-backgrinding process) using a grinding pad K until it reaches a predetermined thickness (see Figure 4B). In the stealth dicing process, weakened portions for separating the semiconductor wafer W into small pieces (dies) are formed inside the semiconductor wafer W. The weakened portions are formed inside the semiconductor wafer W by irradiating the thinned semiconductor wafer W with laser light (see FIG. 4C). Furthermore, as shown in FIG. 4D, the semiconductor wafer W with the backgrinding tape G attached may be further ground to thin the thickness of the semiconductor wafer W to the thickness of the chips (dies) that will be produced by subsequent cleaving.

[0093] In the mounting step, as shown in Figures 5A and 5B, the semiconductor wafer W is fixed to the dicing die bond film 1. Specifically, while a dicing ring R is attached to the adhesive layer 22 of the dicing tape 20, the semiconductor wafer W, whose thickness has been reduced by the cutting process described above, is attached to the exposed surface of the adhesive layer 11 (die bond sheet) (see Figure 5A). Subsequently, the backgrinding tape G is peeled off from the semiconductor wafer W (see Figure 5B).

[0094] In the expanding process, as shown in FIGS. 5C to 5E, the dicing tape 20 is stretched to cleave the semiconductor wafer W and further increase the distance between adjacent semiconductor chips (dies) X. Specifically, a dicing ring R is attached to the adhesive layer 22 of the dicing tape 20, and then the dicing ring R is fixed to a holder H of an expanding device (see FIG. 5C). A push-up member U provided in the expanding device is pushed up from below the dicing die bond film 1, stretching the dicing die bond film 1 so as to expand it in the planar direction (see FIG. 5D). This cleaves the semiconductor wafer W under specific temperature conditions. The temperature conditions are, for example, −20°C or higher and 0°C or lower, preferably −15°C or higher and 0°C or lower, and more preferably −10°C or higher and −5°C or lower. The expanded state is released by lowering the push-up member U (see FIG. 5E; this is the low-temperature expanding process). When the expanding step is performed at such a low temperature, the adhesive layer 11 (die-bonding sheet) needs to be cleaved. The adhesive layer 11 (die-bonding sheet) of the present embodiment described above is designed to be cleaved well at this time. 5F and 5G, the dicing tape 20 is stretched to expand its area under higher temperature conditions (for example, 10°C or higher and 25°C or lower), thereby separating adjacent semiconductor chips X after cleaving in the planar direction of the film surface and further widening the kerf (gap) (room temperature expansion process).

[0095] In the pick-up process, as shown in FIG. 5H, the semiconductor chip X with the adhesive layer (die bond sheet) piece 11' attached thereto is peeled off from the adhesive layer 22 of the dicing tape 20. More specifically, the pin members P are raised to push up the semiconductor chip X to be picked up through the dicing tape 20. The pushed-up semiconductor chip X is held by a suction jig J. A pickup collet, for example, is used as the suction jig J.

[0096] In the die bonding process, the semiconductor chip X (X1) with the small piece 11' of the adhesive layer (die bond sheet) attached thereto is bonded to the adherend Z using the suction jig J. In the die bonding process, the semiconductor chip X is generally bonded to the adherend Z under temperature conditions of about 120°C or higher and 150°C or lower. In the die bonding process, as shown in Fig. 6A, a semiconductor chip X2 with a small piece 11' of an adhesive layer (die bond sheet) attached thereto may be bonded to an adherend Z so as to cover the semiconductor chip X1 bonded to the adherend Z. The adhesive layer of the above-described embodiment is particularly useful as the adhesive layer (die bond sheet) used in this manner. In the die bonding step, as shown in FIG. 6A, the semiconductor chips X with the small pieces 11' of the adhesive layer 11 (die bonding sheet) attached thereto may be stacked multiple times.

[0097] In the curing step, in order to promote the hardening of the pieces 11' of the adhesive layer 11 (die-bonding sheet), a heat treatment is performed at a temperature of, for example, 100°C or higher and 150°C or lower. At this time, pressure can be applied to the pieces 11' of the adhesive layer 11 (die-bonding sheet). The heat treatment is performed while applying a pressure of preferably 0.2 MPa or higher and 2 MPa or lower, more preferably 0.4 MPa or higher and 1 MPa or lower.

[0098] In the wire bonding process, a semiconductor chip X (die) and an adherend Z are connected with a wire L while being heated (see FIG. 6A).

[0099] 6B, the semiconductor chip X (die) and the small piece 11' of the adhesive layer 11 (die bond sheet) are sealed with a thermosetting resin M such as epoxy resin. In the sealing process, the thermosetting resin M is flowed and then hardened by heating at a temperature of, for example, 150°C to 200°C while applying pressure.

[0100] After the sealing step, a reflow soldering step may be performed in which the electrodes are electrically joined by molten solder, for example, by heat treatment at a temperature of 230° C. or higher and 270° C. or lower.

[0101] In the above-mentioned method for manufacturing a semiconductor device (method for using a dicing die bond film), an example in which a semiconductor wafer W having a weak portion formed therein is broken into small pieces in an expanding process has been described in detail, but the present invention is not limited to such an example. For example, instead of forming a weak portion inside the semiconductor wafer W, a semiconductor wafer W that has been subjected to a so-called half-cut process may be split into small pieces in the expanding step. Furthermore, for example, when the above-described pre-back grinding process is performed on a semiconductor wafer W having a weak portion formed therein or a semiconductor wafer W that has been subjected to a half-cut process, the semiconductor wafer W may be divided into small pieces.

[0102] The adhesive sheet (adhesive layer) of this embodiment is as exemplified above, but the present invention is not limited to the adhesive sheet (adhesive layer) exemplified above. That is, various forms used in general adhesive sheets (such as die bond sheets) can be employed within the scope that does not impair the effects of the present invention.

[0103] The matters disclosed by this specification include the following. (1) An adhesive sheet having an adhesive layer in which a plurality of monolayers are laminated, At least two adjacent monolayers each contain an organic component containing at least a thermoplastic component and a thermosetting component, and an inorganic filler dispersed in the organic component; In each of the monolayers, the maximum value of the Hansen solubility parameter distance between the thermoplastic component and the thermosetting component is 8.5 or less; In at least one of the monolayers of the adhesive layer after curing, the organic component is in a non-phase-separated state, and the inorganic filler is dispersed in the non-phase-separated organic component, or an adhesive sheet in which, in at least one of the monolayers in the adhesive layer after curing, the organic component is in a phase-separated state, and a dispersed phase containing a larger amount of the thermosetting component than the thermoplastic component is dispersed in a continuous phase containing a larger amount of the thermoplastic component than the thermosetting component, and the inorganic filler is dispersed in the dispersed phase. (2) The adhesive sheet according to (1) above, wherein the adhesive layer after curing has a storage modulus of 500 MPa or more and 3000 MPa or less at 85°C. (3) The adhesive sheet according to (1) or (2) above, wherein the adhesive layer has a melt viscosity at 120°C of 1000 Pa·s or more and 8000 Pa·s or less. (4) At least two adjacent monolayers in the adhesive layer each contain at least an acrylic polymer as the thermoplastic component; The adhesive sheet according to any one of (1) to (3) above, wherein the proportion of the acrylic polymer in the total amount of the organic components in each of the monolayers is 15% by mass or more and 35% by mass or less. (5) The adhesive sheet according to any one of (1) to (4) above, wherein at least two adjacent monolayers in the adhesive layer each contain 25% by mass or more and 50% by mass or less of the inorganic filler. (6) The adhesive sheet according to any one of (1) to (5) above, wherein at least two adjacent monolayers in the adhesive layer each contain a urea catalyst as a curing catalyst. [Example]

[0104] The present invention will now be described in more detail with reference to experimental examples, but the present invention is not limited to these examples.

[0105] An adhesive sheet (adhesive layer) was produced as follows: This adhesive sheet (adhesive layer) was used as a die bond sheet and attached to a dicing tape to produce a dicing die bond film.

[0106] <Production of die bond sheet> The raw materials having the respective compositions shown in Table 1 were added to and mixed with methyl ethyl ketone to obtain a composition for adhesive layer having a solid content concentration of 15 mass %. Details of each raw material are shown below.

[0107] (thermoplastic component) [SG-708-6] Acrylic polymer (containing carboxyl and hydroxyl groups) solution (solid content 20% by mass) Mass average molecular weight: Mw=700,000 Product name: "Teisan Resin SG-708-6" manufactured by Nagase ChemteX Corporation Acid value: 9 [mgKOH / g] Glass transition temperature Tg: 4℃ SG-N50 Acrylic polymer (containing carboxyl and hydroxyl groups) solution (solid content 25% by mass) Mass average molecular weight: Mw=900,000 Product name: "Teisan Resin SG-N50" manufactured by Nagase ChemteX Corporation Acid value: 35[mgKOH / g] Glass transition temperature Tg: 0℃ SG-70L Acrylic polymer (containing carboxyl and hydroxyl groups) solution (solid content 12.5% ​​by mass) Mass average molecular weight: Mw=900,000 Product name: "Teisan Resin SG-70L" manufactured by Nagase ChemteX Corporation Acid value: 5 [mgKOH / g] Glass transition temperature Tg: -13℃ SG-N80 Acrylic polymer (containing carboxyl and hydroxyl groups) solution (solid content 23% by mass) Mass average molecular weight: Mw=900,000 Product name: "Teisan Resin SG-N80" manufactured by Nagase ChemteX Corporation Acid value: 10 [mgKOH / g] Glass transition temperature Tg: -23℃

[0108] (Thermosetting component) Epoxy resin [EPPN-501HY] Trisphenolmethane epoxy resin Product name: "EPPN-501HY" manufactured by Nippon Kayaku Co., Ltd. Epoxy equivalent: 166 [g / eq] [N-665-EXP-S] Cresol novolac epoxy resin Product name: "EPICLON N-665-EXP-S" manufactured by DIC Epoxy equivalent: approx. 200 [g / eq] HP-7200 Dicyclopentadiene epoxy resin Product name: "EPICLON HP-7200" manufactured by DIC Epoxy equivalent: approx. 260 [g / eq] [KI-3000] Cresol novolac epoxy resin Product name: "KI-3000" manufactured by Tohto Kasei Co., Ltd. Epoxy equivalent: approx. 200 [g / eq] HP-4700 Naphthalene-type epoxy resin Product name: "EPICLON HP-4700" manufactured by DIC Epoxy equivalent: approx. 165 [g / eq]

[0109] (Thermosetting component) Phenolic resin MEHC-7800H Phenol-xylylene resin Product name: MEHC-7800H, manufactured by UBE Hydroxyl group equivalent: 180[g / eq] [MEHC-7851SS] Biphenyl aralkyl phenolic resin Product name: MEHC-7851SS, manufactured by UBE Hydroxyl group equivalent: 203[g / eq] MEH-8000H Allylated phenol novolac resin Product name: MEH-8000H, manufactured by UBE Hydroxyl group equivalent: 141[g / eq] LVR-8210DL Novolac phenolic resin Product name: "LVR-8210DL" manufactured by Gun-ei Chemical Co., Ltd. Hydroxyl group equivalent: 104[g / eq] HF-1M Novolac phenolic resin Product name: "HF-1M" manufactured by UBE Hydroxyl group equivalent: 106[g / eq]

[0110] (inorganic filler) [SE-2050MCV] Spherical silica filler (60% solids MEK dispersion) Product name: "SE-2050MCV" manufactured by Admatechs Average primary particle size 500nm (curing catalyst) ·[Urea catalyst] Aliphatic dimethylurea Product name: U-CAT 3513N, manufactured by San-Apro Co., Ltd. [TPP-K] Product name: “TPP-K” Manufactured by Hokuko Chemical Industry Co., Ltd. Tetraphenylphosphonium tetraphenylborate (Silane coupling agent) [KBM-303] 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane Product name: "KBM-303" manufactured by Shin-Etsu Chemical Co., Ltd.

[0111] Example 1 Of the above raw materials, the following raw materials were mixed in the amounts shown below to prepare a composition for adhesive layer (solid content 40% by mass). The composition for adhesive layer was then applied to one side of a release liner (the silicone-treated side of a 50 μm-thick PET sheet) using an applicator. The solvent was then evaporated from the composition for adhesive layer by drying at 130°C for 2 minutes. In this way, a single layer of adhesive layer (40 μm thick) was obtained on one side of the release liner. Three single layers were stacked together to produce an adhesive sheet. Acrylic polymer solution [SG-708-6] 100 parts by mass Epoxy resin [EPPN-501HY] 37.2 parts by mass Phenolic resin [MEHC-7800H] 22.8 parts by mass Silica filler dispersion [SE-2050MCV] 123 parts by mass ·Curing catalyst [urea catalyst] 0.125 parts by mass Silane coupling agent [KBM-303] 0.46 parts by mass Solvent: Methyl ethyl ketone The formulations expressed in terms of solid content are shown in Table 1.

[0112] (Examples 2 to 12, Comparative Examples 1 to 5) Each adhesive layer (adhesive sheet) was produced in the same manner as in Example 1, except that the raw materials and blending compositions were changed to those shown in Tables 1 and 2, respectively.

[0113] [Table 1]

[0114] The HSP values ​​of the thermoplastic and thermosetting components used to prepare each adhesive layer were determined according to the method described above. The results are shown in Table 2. The storage modulus and melt viscosity of each adhesive layer were measured according to the methods described above. The results are shown in Table 2. Furthermore, each adhesive layer was subjected to a series of pretreatments, including resin embedding, mechanical polishing, ion polishing (IP), and finally conductive treatment, to prepare samples for observation with a field emission scanning electron microscope (FE-SEM).The cross sections of each sample were then observed under the following conditions. [Electron microscope observation conditions] Electron staining: No staining ·Magnification: 20,000x (20,000x) Observation area: Approximately square area with at least 5 μm on each side Acceleration voltage: 3 kV As representative examples of the observed images, the observed images of Example 1, Example 12, and Comparative Example 4 are shown in Figures 7A to 7C, respectively. In the examples and comparative examples, when the organic components are phase-separated, this is also called a sea-island structure, and therefore in Table 2 the dispersed phase is also referred to as islands and the continuous phase as a sea.

[0115] [Table 2]

[0116] <Performance evaluation> The performance of each adhesive layer produced was evaluated as follows.

[0117] (Delamination between monolayers) A temperature cycle test was conducted to artificially create an environment in which delamination is likely to occur. Using a temperature cycle tester, test samples (three single-layer laminate samples) of each example were subjected to a maximum of 1,000 cycles of temperature changes in the range of -55°C to 125°C. The temperature profile of one cycle included a 5-minute hold period at -55°C and a 5-minute hold period at 125°C. After the temperature cycle test, the test samples were mechanically polished vertically to expose the cross section (cross section cut in the thickness direction) of the adhesive layer of each test sample. The exposed polished surface was then observed under an optical microscope and evaluated according to the following criteria. No delamination: Good (〇) Delamination: Poor (×)

[0118] (Crack occurrence inside adhesive layer TCT crack test) The test samples prepared as described above were subjected to a temperature cycle test (TCT) up to a predetermined number of cycles. The adhesive layer of each test sample was then horizontally polished by mechanical polishing to expose the substrate-side surface of the adhesive layer. The exposed surface was then observed and evaluated according to the following criteria: No cracks even after 1000 cycles: Excellent (◎) No cracks after 800 cycles: Good (〇) No cracks after 500 cycles: Pass (△) Cracks occurred after 500 cycles: Failure (×)

[0119] As can be seen from the above evaluation results, the adhesive layers of the examples suppressed both the occurrence of peeling between the single layers and the occurrence of internal cracks. On the other hand, in the adhesive layer of the comparative example, neither the occurrence of peeling between the single layers nor the occurrence of internal cracks was suppressed. [Industrial Applicability]

[0120] The adhesive sheet (adhesive layer) of the present invention is suitably used, for example, as an auxiliary tool when manufacturing a semiconductor device having a semiconductor integrated circuit. [Explanation of symbols]

[0121] 1: dicing die bond film, 10: adhesive sheet, 11: adhesive layer (die bond sheet), 11a: single layer, 12: release liner, 20: dicing tape, 21: Base material layer, 22: Adhesive layer.

Claims

1. An adhesive sheet having an adhesive layer in which a plurality of monolayers are laminated, At least two adjacent monolayers each contain an organic component containing at least a thermoplastic component and a thermosetting component, and an inorganic filler dispersed in the organic component; In each of the monolayers, the maximum value of the Hansen solubility parameter distance between the thermoplastic component and the thermosetting component is 8.5 or less; In at least one of the monolayers of the adhesive layer after curing, the organic component is in a non-phase-separated state, and the inorganic filler is dispersed in the non-phase-separated organic component, or In at least one of the monolayers in the adhesive layer after curing, the organic component is in a phase-separated state, and a dispersed phase containing a thermosetting component in a larger amount than the thermoplastic component is dispersed in a continuous phase containing a thermoplastic component in a larger amount than the thermosetting component, and the inorganic filler is dispersed in the dispersed phase. Adhesive sheet.

2. The adhesive sheet according to claim 1 , wherein the adhesive layer after curing has a storage modulus of 500 MPa or more and 3000 MPa or less at 85° C.

3. The adhesive sheet according to claim 1 or 2, wherein the adhesive layer has a melt viscosity of 1000 Pa·s or more and 8000 Pa·s or less at 120°C.

4. At least two adjacent monolayers in the adhesive layer each contain at least an acrylic polymer as the thermoplastic component; 3. The adhesive sheet according to claim 1, wherein the proportion of the acrylic polymer in the total amount of the organic components in each of the monolayers is 15% by mass or more and 35% by mass or less.

5. The adhesive sheet according to claim 1 or 2, wherein at least two adjacent monolayers in the adhesive layer each contain 25% by mass or more and 50% by mass or less of the inorganic filler.

6. The adhesive sheet according to claim 1 or 2, wherein at least two adjacent monolayers in the adhesive layer each contain a urea catalyst as a curing catalyst.

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