Film-like adhesive, adhesive film, dicing / die bonding integrated film, and method for manufacturing semiconductor device

Abstract

To provide a film-like adhesive that has a barrier function that prevents the migration of heavy metal ions, such as copper ions, and that can suppress the generation of voids and the exudation of resin from the edges.SOLUTION: A film-like adhesive having a single-layer structure includes a resin composition that is thermosetting and contains a filler, the film-like adhesive has a first surface and a second surface, the film-like adhesive has a region near the first surface in which the filler content decreases from the second surface side toward the first surface side, and a recess is formed in the first surface.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a film adhesive, an adhesive film, a dicing / die bonding integrated film, and a method for manufacturing a semiconductor device. [Background technology]

[0002] In recent years, as smartphones, tablet PCs, and other devices have become more sophisticated and faster, the semiconductor packages used in them are being required to be even smaller, have higher capacity, are faster, and are thinner. The wafers used in these semiconductor packages are seeing further miniaturization of the wiring, and the chips tend to become even thinner when assembled into semiconductor packages.

[0003] Amid these trends, problems of operational malfunctions caused by trace amounts of heavy metal ions, such as copper ions, have begun to become apparent, particularly in the fields of DRAM and NAND flash memory. It has been known that when heavy metal ions come into contact with silicon crystals, they can diffuse within the crystal and reach the circuit surface, causing operational malfunctions. To prevent operational malfunctions, gettering treatment is typically performed on silicon wafers during semiconductor package assembly to capture heavy metal ions and prevent them from diffusing to the circuit surface.

[0004] Gettering processes mainly involve providing a gettering layer inside the wafer (intrinsic gettering, hereinafter referred to as "IG") and providing a gettering layer on the backside of the wafer (extrinsic gettering, hereinafter referred to as "EG"). However, with IG, the thickness of the internal gettering layer is reduced due to the trend toward thinner chips, making its effectiveness insufficient. Furthermore, with EG, microcracks are formed on the backside of the wafer, reducing the die strength of the chip. Therefore, excessive gettering is difficult to perform, especially on ultrathin wafers, which are difficult to handle. In light of this situation, efforts have been made to impart gettering functionality for capturing heavy metal ions to resin films (adhesive films used in the manufacturing process of semiconductor devices), more specifically, film-like adhesives (die-bonding films) used to bond chips to substrates or between chips themselves (see, for example, Patent Documents 1 and 2). [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Laid-Open No. 2011-213878 [Patent Document 2] Japanese Patent Application Laid-Open No. 2012-241157 Summary of the Invention [Problem to be solved by the invention]

[0006] However, conventional film adhesives are insufficient in terms of suppressing defects associated with the migration of copper ions within the adhesive, and there is still room for improvement. Furthermore, when the film adhesive is applied, voids may occur or resin may leak from the edges of the film adhesive.

[0007] Therefore, the present invention provides a film-like adhesive that has a barrier function that prevents the migration of heavy metal ions, such as copper ions, and that can suppress the generation of voids and the exudation of resin from the edges, and an adhesive film that includes the film-like adhesive.The present invention also provides an integrated dicing and die bonding film that includes the film-like adhesive as a first adhesive layer, and a method for manufacturing a semiconductor device using the same. [Means for solving the problem]

[0008] One aspect of the present invention includes the following [1] to

[12] . [1] A film-like adhesive having a single-layer structure, which is composed of a thermosetting resin composition containing a filler and has a first surface and a second surface, the film adhesive has a region in the vicinity of the first surface, in which the filler content decreases from the second surface side toward the first surface side; A film-like adhesive having recesses formed on the first surface. [2] A film-like adhesive having a single-layer structure, which is composed of a thermosetting resin composition containing a filler and has a first surface and a second surface, when the film-like adhesive is cured by heating, the film-like adhesive after thermal curing has a region in the vicinity of the first surface, in which the filler content decreases from the second surface side toward the first surface side, A film adhesive having recesses formed on the first surface. [3] The film adhesive according to [1] or [2], wherein the thickness of the region is 2 μm or less. [4] The film adhesive according to any one of [1] to [3], wherein the ratio of the thickness of the region to the total thickness of the film adhesive is 0.3 to 25%. [5] The film adhesive according to any one of [1] to [4], wherein the region is located at a position shallower than 2 μm in depth from the first surface. [6] The film adhesive according to any one of [1] to [5], wherein the content of the filler is 3 to 55 mass % based on the total mass of the resin composition. [7] The resin composition contains an acrylic rubber, The film adhesive according to any one of [1] to [6], wherein the content of the acrylic rubber is 50 to 85 mass % based on the total mass of the resin composition. [8] The film adhesive according to any one of [1] to [7], wherein the recesses extend in one or more directions within the plane of the first surface. [9] The film adhesive according to any one of [1] to [8], wherein, in a plan view of the first surface, the ratio of the area of ​​the recesses to the area of ​​the first surface is 10 to 70%.

[10] A film-like adhesive according to any one of [1] to [9], a substrate film in contact with the second surface of the film adhesive; An adhesive film comprising:

[11] A first adhesive layer composed of the film-like adhesive according to any one of [1] to [9]; a second adhesive layer in contact with the second surface of the film adhesive; a base film in contact with the second adhesive layer; This is a dicing and die bonding integrated film.

[12] A step of attaching a wafer to the first surface of the film-like adhesive in the dicing-die bonding integrated film according to

[11] ; singulating the wafer and the film adhesive into a plurality of adhesive piece-attached chips; picking up the adhesive strip-attached chip from the second adhesive layer; Pressing the chip onto a substrate or another chip via the adhesive strip; A method for manufacturing a semiconductor device, comprising: [Effects of the Invention]

[0009] The present invention provides a film-like adhesive and an adhesive film comprising the same, which have a barrier function that prevents the migration of heavy metal ions, such as copper ions, and are capable of suppressing the generation of voids and the exudation of resin from edges. The present invention also provides an integrated dicing and die bonding film comprising the film-like adhesive as a first adhesive layer, and a method for manufacturing a semiconductor device using the same. [Brief explanation of the drawings]

[0010] [Figure 1] FIG. 1 is a cross-sectional view that schematically illustrates one embodiment of a film-like adhesive according to the present invention. [Figure 2] 2(a) to 2(c) are plan views each showing a schematic diagram of one embodiment of the film adhesive according to the present invention. [Figure 3] 3(a) to 3(c) are plan views each showing a schematic diagram of one embodiment of the film adhesive according to the present invention. [Figure 4] FIG. 4 is a plan view schematically showing one embodiment of a film adhesive according to the present invention. [Figure 5] FIG. 5 is a plan view schematically showing one embodiment of a film adhesive according to the present invention. [Figure 6] FIG. 6 is a cross-sectional view schematically showing an example of an adhesive film provided with the film-like adhesive shown in FIG. [Figure 7] FIG. 7 is a cross-sectional view schematically showing one embodiment of a dicing-die bonding integrated film according to the present invention. [Figure 8] FIG. 8 is a cross-sectional view schematically showing an example of a semiconductor device. [Figure 9] FIG. 9 is a cross-sectional view schematically showing another example of a semiconductor device. [Figure 10] FIG. 10 is a cross-sectional view schematically showing another embodiment of the film adhesive according to the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0011] Hereinafter, embodiments of the present invention will be described with reference to the drawings as appropriate. However, the present invention is not limited to the following embodiments. In the following embodiments, the components (including steps, etc.) are not essential unless specifically stated. The sizes of the components in each drawing are conceptual, and the relative size relationships between the components are not limited to those shown in each drawing.

[0012] The same applies to numerical values ​​and ranges in this specification, and do not limit the present invention. In this specification, numerical ranges indicated using "to" indicate ranges that include the numerical values ​​before and after "to" as the minimum and maximum values, respectively. In numerical ranges described in stages in this specification, the upper or lower limit value described in one numerical range may be replaced with the upper or lower limit value of another numerical range described in stages. Furthermore, in numerical ranges described in this specification, the upper or lower limit value of that numerical range may be replaced with a value shown in the Examples. In this specification, (meth)acrylate means acrylate or the corresponding methacrylate. The same applies to other similar expressions such as (meth)acryloyl group and (meth)acrylic copolymer.

[0013] <Film adhesive> FIG. 1 is a cross-sectional view schematically illustrating a film-like adhesive according to this embodiment. The film-like adhesive 1 shown in this figure has a single-layer structure composed of a thermosetting resin composition containing a filler. The thickness of the film-like adhesive 1 may be 50 μm or less, for example, 40 μm or less, 30 μm or less, 20 μm or less, or 10 μm or less. If the thickness of the film-like adhesive 1 is 50 μm or less, the distance between the semiconductor element and the support member on which the semiconductor element is mounted becomes short, which tends to make problems due to heavy metal ions more likely to occur, and therefore the effects of the present invention are more easily achieved. The lower limit of the thickness of the film-like adhesive 1 is not particularly limited, but is, for example, 2 μm or more. If the thickness of the film-like adhesive 1 is 2 μm or more, a film with a better appearance tends to be obtained more easily.

[0014] The film adhesive 1 has a region R1 near the first surface F1 where the filler content decreases from the second surface F2 toward the first surface F1 (the region whose thickness is indicated by the arrow in the enlarged view shown in FIG. 1). At this time, the film adhesive 1 may be either uncured or cured.

[0015] Region R1 is composed of a plurality of fillers 1f and a resin component. In region R1, the filler content may decrease continuously or stepwise. Region R1 serves to prevent the migration of heavy metal ions. That is, the relatively low filler content in region R1 located near first surface F1 means that, near first surface F1, a region with a relatively high resin component content (resin-rich region) is formed locally in the thickness direction, while being formed with a continuous spread in the planar direction. Region R1 is denser than other regions, and is therefore presumed to have a barrier function that prevents the migration of heavy metal ions.

[0016] Region R1 according to this embodiment is located at a depth of less than 2 μm from the first surface F1, although this varies depending on the thickness of the film adhesive 1. In other words, "vicinity of the first surface F1" in this embodiment refers to a region that is less than 2 μm deep from the first surface F1. It is sufficient that region R1 exists near the first surface F1; for example, a region with a high filler content may exist locally on the first surface F1.

[0017] The presence and thickness of region R1 can be confirmed, for example, by impacting a slurry containing abrasive grains against the first surface F1 at high speed and measuring the wear rate, or by measurement using a rigid pendulum-type physical property tester. In particular, the method of impacting a slurry containing abrasive grains at high speed to measure the wear rate can sufficiently reduce the thermal effects on the film adhesive 1. The presence and thickness of region R1 can also be confirmed after the film adhesive 1 is cured by heating. Specifically, a heat-cured film adhesive and a heat-cured film adhesive with the vicinity of the first surface F1 physically removed can be prepared, and the compositional difference between the two can be determined by changing the ATR crystal and changing the penetration depth during measurement. The presence and thickness of region R1 can also be confirmed by observing the cross-section of the film adhesive.

[0018] The thickness of region R1 is, for example, 0.05 to 2 μm, and may be 0.1 to 1.5 μm or 0.3 to 1 μm. When the thickness of region R1 is 0.05 μm or more, region R1 tends to be able to function as an impediment to the migration of heavy metal ions. Furthermore, when the thickness of region R1 is 0.1 μm or more, region R1 tends to be able to fully function as an impediment to the migration of heavy metal ions. On the other hand, when the thickness of region R1 is 2 μm or less, the handleability of the film adhesive 1 tends to be easily maintained.

[0019] The ratio of the thickness of region R1 to the total thickness of the film-like adhesive 1 is, for example, 0.3 to 25%, or may be 1 to 20%, or 3 to 15%. When this ratio is 0.3% or more, region R1 tends to be able to function as an impediment to the migration of heavy metal ions, and when this ratio is 1% or more, region R1 tends to be able to sufficiently function as an impediment to the migration of heavy metal ions. On the other hand, when this ratio is 25% or less, the mechanical strength of the film-like adhesive 1 can be maintained.

[0020] The film adhesive 1 has a recess D1 on the first surface F1. The film adhesive 1 has a plurality of recesses D1 on the first surface F1, but the film adhesive may have at least one recess on the first surface.

[0021] The recesses D1 may be formed in a specific pattern or randomly in a plan view of the first surface F1. The recesses D1 may be formed uniformly over the entire surface of the film or may be formed partially. The recesses D1 may be groove-shaped, lattice-shaped, or dot-shaped in a plan view of the first surface F1. The recesses D1 may be formed to correspond to the arrangement of chips in the semiconductor device in a plan view of the first surface F1. The region R1 has a relatively low filler content and is therefore flexible, which means that it can be said to have excellent processability when forming the recesses D1. Figures 2 to 5 specifically show the formation patterns of the recesses D1.

[0022] In Figures 2(a) to 2(c), the recesses D1 extend in one in-plane direction of the first surface. Because the recesses D1 extend in one in-plane direction of the first surface, voids are more easily removed along the recesses D1, and the volume of the film-like adhesive in the direction along which the recesses D1 are formed is reduced, thereby further suppressing resin exudation in the direction along which the recesses D1 are formed. The width of the recesses D1 may be non-uniform, and the spacing between the recesses D1 may also be non-uniform. For example, when the width of the central recess D1 among the multiple recesses D1 is large, as in Figure 2(b), or when there are many central recesses D1 among the multiple recesses D1 in a planar view of the first surface, in addition to the above effects, the volume of the film-like adhesive at the center of the side portion S1 on the end side of the recess D1 is further reduced, thereby further suppressing resin exudation at the center of the side portion S1 of the film-like adhesive. 2, the recess D1 is formed in a straight line, but the shape of the recess is not limited to a straight line and may be a dashed line, a wavy line, etc. Also, in FIG. 2, the end of the recess D1 and the side of the film adhesive are aligned, but the recess does not extend to the side of the film adhesive, and the end of the recess may be within the plane of the first surface of the film adhesive.

[0023] In Figures 3(a) to 3(c), the recesses D1 extend in multiple directions within the plane of the first surface. Because the recesses D1 extend in multiple directions within the plane of the first surface, voids are more easily removed along the recesses. Furthermore, the reduced volume of the film-like adhesive further suppresses resin seepage along the direction in which the recesses D1 are formed. Furthermore, when the width of the central recess D1 among the multiple recesses D1 is large, as in Figure 3(b), or when there are a large number of central recesses D1 among the multiple recesses D1 in a planar view of the first surface, in addition to the above-described effects, the volume of the film-like adhesive at the center of the side portion S1 on the edge side of the recess D1 is further reduced, further suppressing resin seepage at the center of the side portion S1 of the film-like adhesive. While the recesses D1 are formed linearly in Figure 3, the shape of the recesses is not limited to linear and may be dashed, wavy, or the like. Also, in Figure 3, the end of the recess D1 coincides with the side of the film-like adhesive, but the recess may not extend to the side of the film-like adhesive, and the end of the recess may be within the plane of the first surface of the film-like adhesive.

[0024] In Fig. 4, the recesses D1 are formed at regular intervals within the first surface. By forming the recesses D1 at regular intervals within the first surface, the volume of the film-like adhesive is reduced, which makes it possible to further suppress resin seepage in all directions within the first surface, and also makes the density of the resin uniform within the first surface, making it easier to maintain sufficient adhesive strength. Note that in Fig. 4, the recesses D1 are formed in a circular shape, but the shape of the recess is not limited to a circular shape and may be a rectangular shape, a polygonal shape, an elliptical shape, or the like.

[0025] In Fig. 5, recess D1 is formed on the side of the film adhesive. By forming recess D1 on the side of the film adhesive, the volume of the side of the film adhesive is reduced, which makes it possible to further suppress the exudation of resin from the side of the first surface F1 on which recess D1 is formed. Note that, although recess D1 is formed in a semicircular shape in Fig. 5, the shape of the recess is not limited to a semicircular shape and may be rectangular, polygonal, or the like.

[0026] The shape of the recess D1 in the cross section of the film adhesive 1 is rectangular. The shape of the recess in the cross section of the film adhesive is not particularly limited, and may be semicircular, triangular, polygonal, irregular, or the like.

[0027] The depth of the recesses D1 (the length in the thickness direction of the film-like adhesive 1) may be 8 μm or less, 5 μm or less, or 2 μm or less to avoid insufficient resin filling during bonding, and may be 0.5 μm or more, 1 μm or more, or 2 μm or more to further suppress the occurrence of voids and resin seepage. The depth of the recesses D1 may be greater or less than the thickness of the region R1. The depths of the multiple recesses D1 may be the same or different.

[0028] In a plan view of the first surface F1, the ratio of the area of ​​the recesses D1 to the area of ​​the first surface F1 (the total area if there are multiple recesses D1) may be 10% or more, 20% or more, or 30% or more from the viewpoint of further suppressing the generation of voids and resin seepage, and may be 70% or less, 60% or less, or 50% or less from the viewpoint of more sufficiently suppressing the movement (permeation) of heavy metal ions in the adhesive. From these viewpoints, in a plan view of the first surface F1, the ratio of the area of ​​the recesses D1 to the area of ​​the first surface F1 may be 10 to 70%, 20 to 60%, or 30 to 50%.

[0029] The film-like adhesive 1 is composed of an adhesive composition containing (A) a thermosetting resin component and (B) a filler. The film-like adhesive 1 may be capable of passing through a semi-cured (B-stage) state and then becoming a cured (C-stage) state after a curing treatment. In one embodiment, the (A) thermosetting resin component may include (A1) a thermosetting resin, (A2) a curing agent, and (A3) an elastomer.

[0030] (A1) Component: Thermosetting resin From the viewpoint of adhesiveness, the component (A1) may be an epoxy resin. Any epoxy resin having an epoxy group in the molecule may be used without particular limitation. Examples of epoxy resins include bisphenol A epoxy resins, bisphenol F epoxy resins, bisphenol S epoxy resins, phenol novolac epoxy resins, cresol novolac epoxy resins, bisphenol A novolac epoxy resins, bisphenol F novolac epoxy resins, stilbene epoxy resins, triazine skeleton-containing epoxy resins, fluorene skeleton-containing epoxy resins, triphenolmethane epoxy resins, biphenyl epoxy resins, xylylene epoxy resins, biphenyl aralkyl epoxy resins, naphthalene epoxy resins, polyfunctional phenols, and diglycidyl ether compounds of polycyclic aromatics such as anthracene. These may be used alone or in combination of two or more. Among these, the component (A1) may be a cresol novolac epoxy resin, a phenol novolac epoxy resin, a bisphenol F epoxy resin, or a bisphenol A epoxy resin, from the viewpoint of film tackiness, flexibility, and the like.

[0031] The epoxy equivalent of the epoxy resin is not particularly limited, but may be 90 to 300 g / eq or 110 to 290 g / eq. When the epoxy equivalent of the epoxy resin is within this range, the film adhesive tends to maintain its bulk strength while ensuring its fluidity.

[0032] Component (A2): Hardener Component (A2) may be a phenolic resin that can serve as a curing agent for epoxy resins. Any phenolic resin can be used without particular limitation as long as it has a phenolic hydroxyl group in the molecule. Examples of phenolic resins include novolak-type phenolic resins obtained by condensing or co-condensing phenols such as phenol, cresol, resorcinol, catechol, bisphenol A, bisphenol F, phenylphenol, and aminophenol and / or naphthols such as α-naphthol, β-naphthol, and dihydroxynaphthalene with a compound having an aldehyde group such as formaldehyde under an acidic catalyst; phenol aralkyl resins and naphthol aralkyl resins synthesized from phenols such as allylated bisphenol A, allylated bisphenol F, allylated naphthalenediol, phenol novolak, and / or naphthols with dimethoxyparaxylene or bis(methoxymethyl)biphenyl; and the like. These resins may be used alone or in combination of two or more. Among these, the phenol resin may be a phenol novolac type phenol resin or a naphthol aralkyl resin.

[0033] The hydroxyl equivalent of the phenolic resin may be 70 g / eq or more, or 70 to 300 g / eq. If the hydroxyl equivalent of the phenolic resin is 70 g / eq or more, the storage modulus of the film tends to be further improved, and if it is 300 g / eq or less, defects due to the generation of foaming, outgassing, etc. can be prevented.

[0034] From the viewpoint of curability, the ratio of the epoxy equivalent of the epoxy resin to the hydroxyl equivalent of the phenolic resin (epoxy equivalent of the epoxy resin / hydroxyl equivalent of the phenolic resin) may be 0.30 / 0.70 to 0.70 / 0.30, 0.35 / 0.65 to 0.65 / 0.35, 0.40 / 0.60 to 0.60 / 0.40, or 0.45 / 0.55 to 0.55 / 0.45. When the equivalent ratio is 0.30 / 0.70 or more, more sufficient curability tends to be obtained. When the equivalent ratio is 0.70 / 0.30 or less, excessive viscosity can be prevented, and more sufficient fluidity can be obtained.

[0035] The total amount of the (A1) and (A2) components may be 5 to 50 parts by mass, 10 to 40 parts by mass, or 15 to 30 parts by mass, based on 100 parts by mass of the total amount of the (A) component. When the total amount of the (A1) and (A2) components is 5 parts by mass or more, the elastic modulus tends to be improved by crosslinking. When the total amount of the (A1) and (A2) components is 50 parts by mass or less, the film handleability tends to be maintained.

[0036] (A3) Component: Elastomer The component (A3) may be an acrylic rubber having, as a main component, structural units derived from a (meth)acrylic acid ester. The content of structural units derived from a (meth)acrylic acid ester in the component (A3) may be, for example, 70% by mass or more, 80% by mass or more, or 90% by mass or more, based on the total amount of structural units. The acrylic rubber may contain structural units derived from a (meth)acrylic acid ester having a crosslinkable functional group such as an epoxy group, an alcoholic or phenolic hydroxyl group, or a carboxyl group. Furthermore, the acrylic rubber may contain structural units derived from acrylonitrile. However, since this can more effectively inhibit the permeation of heavy metal ions into the adhesive and achieve better embeddability, the component (A3) may not contain structural units derived from acrylonitrile.

[0037] The glass transition temperature (Tg) of component (A3) may be -50 to 50°C or -30 to 30°C. When the Tg of component (A3) is -50°C or higher, it tends to be possible to prevent the flexibility of the adhesive from becoming too high. This makes it easier to cut the film-like adhesive during wafer dicing, and makes it possible to prevent the occurrence of burrs. When the Tg of component (A3) is 50°C or lower, it tends to be possible to suppress a decrease in the flexibility of the adhesive. This tends to make it easier to sufficiently fill voids when the film-like adhesive is attached to a wafer. It also makes it possible to prevent chipping during dicing due to a decrease in wafer adhesion. Here, the glass transition temperature (Tg) refers to a value measured using a DSC (differential scanning calorimeter) (e.g., Thermo Plus 2, manufactured by Rigaku Corporation).

[0038] The weight-average molecular weight (Mw) of component (A3) may be 100,000 to 3,000,000 or 200,000 to 2,000,000. When the Mw of component (A3) is within this range, it is possible to appropriately control the film-forming properties, film strength, flexibility, tackiness, etc., and also to achieve excellent reflowability and improved embeddability. Here, Mw refers to a value measured by gel permeation chromatography (GPC) and converted using a calibration curve based on standard polystyrene.

[0039] Commercially available products of the component (A3) include, for example, improved SG-P3 and SG-80H (both manufactured by Nagase ChemteX Corporation).

[0040] The content of component (A3) may be 50 to 95 parts by mass, 60 to 90 parts by mass, or 70 to 85 parts by mass, based on 100 parts by mass of the total mass of component (A). When the content of component (A3) is within this range, migration (permeation) of heavy metal ions within the adhesive tends to be more effectively suppressed. When component (A3) is an acrylic rubber, the content of the acrylic rubber, based on the total mass of the adhesive composition, may be, for example, 50 to 85% by mass, 55 to 80% by mass, or 60 to 80% by mass. A content of 50% by mass or more facilitates the formation of region R1, while a content of 85% by mass or less facilitates the maintenance of workability during the production of the film-like adhesive 1.

[0041] In another embodiment, the (A) thermosetting resin component may contain an elastomer having a crosslinkable functional group such as an epoxy group, an alcoholic or phenolic hydroxyl group, or a carboxyl group, and a curing agent capable of reacting with the crosslinkable functional group. Examples of a combination of an elastomer having a crosslinkable functional group and a curing agent capable of reacting with the crosslinkable functional group include a combination of an acrylic rubber having an epoxy group and a phenolic resin.

[0042] (B) Component: Filler Component (B) may be either an inorganic filler or an organic filler. Examples of inorganic fillers include aluminum hydroxide, magnesium hydroxide, calcium carbonate, magnesium carbonate, calcium silicate, magnesium silicate, calcium oxide, magnesium oxide, aluminum oxide, aluminum nitride, aluminum borate whisker, boron nitride, and silica. These may be used alone or in combination of two or more. Among these, component (B) may be silica from the viewpoint of adjusting the melt viscosity. Examples of organic fillers include carbon, rubber-based fillers, silicone-based fine particles, polyamide fine particles, and polyimide fine particles. The shape of component (B) is not particularly limited, but may be spherical.

[0043] From the viewpoint of fluidity, the average particle size of component (B) may be 0.01 to 1 μm, 0.01 to 0.8 μm, or 0.03 to 0.5 μm, where the average particle size refers to a value determined by conversion from the BET specific surface area.

[0044] The content of component (B) may be 0.1 to 50 parts by mass, 0.1 to 30 parts by mass, or 0.1 to 20 parts by mass, relative to 100 parts by mass of the total mass of component (A). Based on the total mass of the adhesive composition, the content of component (B) is, for example, 3 to 55% by mass, or may be 5 to 50% by mass, or 7 to 40% by mass. A content of 3% by mass or more has the effect of maintaining the mechanical strength of the film-like adhesive 1, while a content of 55% by mass or less has the effect of maintaining a good appearance of the film-like adhesive 1.

[0045] The film-like adhesive (adhesive composition) may further contain (C) a coupling agent, (D) a curing accelerator, and the like.

[0046] Component (C): Coupling agent Component (C) may be a silane coupling agent. Examples of silane coupling agents include γ-ureidopropyltriethoxysilane, γ-mercaptopropyltrimethoxysilane, 3-phenylaminopropyltrimethoxysilane, and 3-(2-aminoethyl)aminopropyltrimethoxysilane. These may be used alone or in combination of two or more.

[0047] Component (D): Curing accelerator The component (D) is not particularly limited, and a commonly used component can be used. Examples of the component (D) include imidazoles and their derivatives, organic phosphorus compounds, secondary amines, tertiary amines, and quaternary ammonium salts. These may be used alone or in combination of two or more. Among these, from the perspective of reactivity, the component (D) may be imidazoles and their derivatives. Examples of the imidazoles include 2-methylimidazole, 1-benzyl-2-methylimidazole, 1-cyanoethyl-2-phenylimidazole, and 1-cyanoethyl-2-methylimidazole. These may be used alone or in combination of two or more.

[0048] The film adhesive 1 may further contain other components. Examples of other components include leveling agents, pigments, ion scavengers, antioxidants, etc. The content of component (C), component (D), and other components may be 0 to 30 parts by mass per 100 parts by mass of the total mass of component (A).

[0049] <Method of manufacturing film adhesive> The film-like adhesive 1 can be formed by applying the adhesive composition to a support film and then forming recesses D1. When a varnish of the adhesive composition (adhesive varnish) is used, the (A) component, the (B) component, and other components added as needed are mixed in a solvent, the mixture is mixed or kneaded to prepare an adhesive varnish, the adhesive varnish is applied to a support film 5, the solvent is removed by drying, and recesses D1 are formed, thereby obtaining the film-like adhesive 1. The recesses D1 may be formed before or after the adhesive varnish is dried. The adhesive film 100 shown in FIG. 6 is composed of a support film 5 and a film-like adhesive 1 provided on the surface of the support film 5.

[0050] When forming the film adhesive 1 from a coating of adhesive varnish, the solvent is removed by drying while air is blown onto the surface of the coating, thereby forming a region R1 near the first surface F1. The speed of the air flowing parallel to the upper surface of the coating is, for example, 3 to 20 m / sec. When this speed is 3 m / sec or more, the drying of component (A) on the surface of the coating that is exposed to the air is promoted, which has the effect of facilitating the formation of a region R1 with sufficient thickness near the first surface F1 of the film adhesive 1. On the other hand, when the speed is 20 m / sec or less, the appearance of the coating surface is easily maintained.

[0051] The drying temperature of the adhesive varnish is, for example, 25 to 150° C., and may be 60 to 145° C. or 70 to 140° C. A drying temperature of 70° C. or higher provides the effect of easily maintaining productivity, while a drying temperature of 150° C. or lower provides the effect of easily suppressing poor appearance.

[0052] The support film 5 is not particularly limited as long as it can withstand the above-mentioned heat drying, and may be, for example, a polyester film, a polypropylene film, a polyethylene terephthalate film, a polyimide film, a polyetherimide film, a polyethylene naphthalate film, a polymethylpentene film, etc. The support film 5 may be a multilayer film made by combining two or more types of film, and may have a surface treated with a silicone-based, silica-based, or other mold release agent. The thickness of the support film 5 may be, for example, 10 to 200 μm or 20 to 170 μm.

[0053] Mixing or kneading can be carried out using a dispersing machine such as a conventional stirrer, a mortar and pestle, a three-roll mill, or a ball mill, and combining these as appropriate. The solvent used to prepare the adhesive varnish is not limited as long as it can uniformly dissolve, knead, or disperse each component, and conventionally known solvents can be used. Examples of such solvents include ketone solvents such as acetone, methyl ethyl ketone, methyl isobutyl ketone, and cyclohexanone, as well as dimethylformamide, dimethylacetamide, N-methyl-2-pyrrolidone, toluene, and xylene. Methyl ethyl ketone, cyclohexanone, and the like may be used as the solvent because of their fast drying rate and low cost. Known methods can be used to apply the adhesive varnish to the support film, including, for example, knife coating, roll coating, spray coating, gravure coating, bar coating, and curtain coating.

[0054] The surface tension of the adhesive varnish is, for example, 27 to 44 mN / m, and may be 28 to 40 mN / m or 28 to 38 mN / m. Having this value within the above range facilitates the production of a film with good appearance and also facilitates maintaining workability during production. The surface tension of the adhesive varnish refers to a value measured by the hanging drop method under windless conditions at room temperature of 22 to 28°C and humidity of 40 to 60%. The surface tension of the adhesive varnish can be adjusted, for example, by blending a leveling agent into the adhesive varnish.

[0055] The recesses D1 can be formed, for example, by applying an adhesive varnish to the support film 5, drying it, and then removing a portion of the dried adhesive varnish by irradiating it with laser light, applying a solvent, or the like. Alternatively, the recesses D1 may be formed by applying an adhesive varnish to the support film 5, drying it, heating the adhesive varnish to 40 to 80°C to soften it, contacting it with a substrate having protrusions or an object with a network structure such as a mesh, and then peeling the substrate or the like after cooling to transfer the shape of the protrusions. Alternatively, the recesses D1 may be formed by applying an adhesive varnish to the support film 5, placing a substrate having protrusions on the adhesive varnish, drying the adhesive varnish, and transferring the shape of the substrate having protrusions.

[0056] The recess D1 may be formed during the manufacture of the semiconductor device. For example, an adhesive varnish may be applied to a semiconductor chip or the like, or a film-like adhesive may be attached, and then the recess may be formed in the adhesive varnish or film-like adhesive. The method for forming the recess is as described above. After the recess is formed, the semiconductor chip or the like may be attached to the surface on which the recess is formed.

[0057] <Dicing and die bonding integrated film> 7 is a schematic cross-sectional view of a dicing-die bonding integrated film comprising a film-like adhesive 1. The dicing-die bonding integrated film 120 shown in this figure comprises, in this order, a first adhesive layer L1 made of the film-like adhesive 1, a second adhesive layer L2 in contact with the second surface F2 of the film-like adhesive 1, and a base film L3 in contact with the second adhesive layer L2. The second adhesive layer L2 and base film L3 form a dicing tape.

[0058] <Semiconductor device> The integrated dicing and die bonding film 120 can be used to manufacture, for example, a semiconductor device as shown in FIG. 8. The semiconductor device 200 shown in FIG. 8 comprises a semiconductor chip 9, a support member 10 on which the semiconductor chip 9 is mounted, and a cured adhesive piece 1c provided between the semiconductor chip 9 and the support member 10. The adhesive piece is an individual piece of film-like adhesive 1. The cured adhesive 1c bonds the semiconductor chip 9 to the support member 10. The connection terminals (not shown) of the semiconductor chip 9 are electrically connected to external connection terminals (not shown) via wires 11 and are sealed with a sealing material 12.

[0059] The semiconductor device shown in Fig. 9 can also be manufactured using the dicing / die bonding integrated film 120. In the semiconductor device 210 shown in Fig. 9, a first-tier semiconductor chip 9a is bonded to a support member 10 with a cured material 1c, and a second-tier semiconductor chip 9b is further bonded onto the first-tier semiconductor chip 9a with a cured material 1c. The connection terminals (not shown) of the first-tier semiconductor chip 9a and the second-tier semiconductor chip 9b are electrically connected to external connection terminals via wires 11 and are sealed with a sealing material 12. Terminals 13 are formed on the underside of the support member 10.

[0060] <Method of manufacturing a semiconductor device> The semiconductor devices 200 and 210 are manufactured, for example, through the following steps. A process of attaching a wafer onto the first surface F1 of the first adhesive layer L1 (film-like adhesive) in the integrated dicing and die bonding film 120. A step of singulating the wafer and the first adhesive layer L1 (film-like adhesive) into a plurality of chips with adhesive pieces. A step of picking up the chip with adhesive piece from the second adhesive layer L2. A process of pressing a semiconductor chip onto a substrate or another semiconductor chip via an adhesive strip.

[0061] The semiconductor devices 200, 210 are obtained, for example, by interposing an adhesive piece between a semiconductor chip and a support member or between two semiconductor chips, bonding them together by thermocompression, and then, as necessary, undergoing a wire bonding process, a sealing process using a sealing material, a heat melting process including solder reflow, etc. In the thermocompression bonding process, the heating temperature is typically 20 to 250°C, the load is typically 0.1 to 200 N, and the heating time is typically 0.1 to 300 seconds.

[0062] The support member may include a copper-based material. The semiconductor devices 200, 210 are manufactured using the film-like adhesive 1, which has a barrier function that prevents the migration of heavy metal ions (e.g., copper ions). Therefore, even when copper-based materials are used as components of the semiconductor device, the effects of copper ions generated from the materials can be reduced, and electrical defects caused by copper ions can be sufficiently suppressed. Examples of copper-based materials include lead frames, wiring, wires, and heat dissipation materials. Regardless of the type of material, copper can be used to reduce the effects of copper ions.

[0063] Although the embodiments of the present invention have been described in detail above, the present invention is not limited to these embodiments. For example, in the above embodiment, an embodiment in which region R1 is formed near the first surface F1 has been illustrated. However, as shown in FIG. 10, a region R2 similar to region R1 may also be formed near the second surface F2. The film-like adhesive 2 shown in the figure has the same configuration as the film-like adhesive 1, except that it further includes region R2, which is a region near the second surface F2 and in which the filler content decreases from the first surface F1 side toward the second surface F2 side. Region R2 is located at a depth of less than 2 μm from the second surface F2. In other words, "near the second surface F2" refers to a region shallower than a depth of 2 μm from the second surface F2. Note that it is sufficient that region R2 exists near the second surface F2; for example, a region with a high filler content may be locally present on the second surface F2.

[0064] The thickness of the film-like adhesive 2 may be 50 μm or less, and may be, for example, 40 μm or less, 30 μm, 20 μm or less, or 10 μm or less. If the thickness of the film-like adhesive 2 is 50 μm or less, the distance between the semiconductor element and the support member on which the semiconductor element is mounted becomes short, which tends to make problems due to heavy metal ions more likely to occur, and therefore the effects of the present invention are more easily achieved. There is no particular lower limit to the thickness of the film-like adhesive 2, but it can be, for example, 2 μm or more. If the thickness of the film-like adhesive 2 is 2 μm or more, a film with a better appearance tends to be obtained more easily.

[0065] The thickness of region R2 is, for example, 0.05 to 2 μm, and may be 0.1 to 1.5 μm or 0.3 to 1 μm. When the thickness of region R2 is 0.05 μm or more, region R2 tends to be able to function as an impediment to the migration of heavy metal ions. Furthermore, when the thickness of region R2 is 0.1 μm or more, region R2 tends to be able to fully function as an impediment to the migration of heavy metal ions. On the other hand, when the thickness of region R2 is 2 μm or less, the handleability of the film-like adhesive 2 is easily maintained.

[0066] The ratio of the thickness of region R2 to the total thickness of the film-like adhesive 2 is, for example, 0.3 to 25%, or may be 1 to 20% or 3 to 15%. When this ratio is 0.3% or more, region R2 tends to be able to function as an impediment to the migration of copper ions. Furthermore, when this ratio is 1% or more, region R2 tends to be able to fully function as an impediment to the migration of heavy metal ions. On the other hand, when this ratio is 25% or less, the mechanical strength of the film-like adhesive 2 can be maintained.

[0067] The film adhesive 2 has recesses D2 on the second surface F2. For the recesses D2 that the film adhesive 2 has on the second surface F2, the above description of the recesses D1 can be referred to as appropriate. [Example]

[0068] The present invention will be specifically described below based on examples and comparative examples, but the present invention is not limited to the following examples.

[0069] (Examples 1 to 6 and Comparative Example 1) [Preparation of film adhesive] <Preparing the adhesive varnish> The adhesive varnish was an acrylic rubber solution shown in Tables 1 and 2. The numerical values ​​relating to the composition shown in Tables 1 and 2 refer to the parts by mass of the solid content of the acrylic rubber solution.

[0070] Epoxy resin N-500P-10 (product name, manufactured by DIC Corporation, o-cresol novolac epoxy resin, epoxy equivalent: 203 g / eq) Hardener (phenolic resin) MEH-7800M (product name, manufactured by Meiwa Chemical Co., Ltd., phenol novolac type phenolic resin, hydroxyl equivalent: 175 g / eq, softening point: 61 to 90°C) PSM-4326 (product name, manufactured by Gun-ei Chemical Industry Co., Ltd., softening point: 120°C) acrylic rubber SG-P3 Improved 1 (product name, manufactured by Nagase ChemteX Corporation) SG-P3 Improved Product 2 (product name, manufactured by Nagase ChemteX Corporation) acrylic rubber with the structural units derived from acrylonitrile removed. inorganic filler R972 (product name, manufactured by Nippon Aerosil Co., Ltd., silica particles, average particle size: 0.016 μm) SC2050-HLG (product name, manufactured by Admatechs Co., Ltd., silica filler dispersion, average particle size: 0.50 μm) Coupling Agent Z-6119 (product name, Dow-Toray Industries, Inc., 3-ureidopropyltriethoxysilane) A-189 (trade name, manufactured by Nippon Unicar Co., Ltd., γ-mercaptopropyltrimethoxysilane) Leveling Agent · BYK-333: Polyether-modified polydimethylsiloxane (manufactured by BYK Chemie Japan Co., Ltd.) · BYK-325N: Polyether-modified polymethylalkylsiloxane (manufactured by BYK Chemie Japan Co., Ltd.) Curing accelerator · 2PZ-CN (trade name, manufactured by Shikoku Kasei Kogyo Co., Ltd., 1-cyanoethyl-2-phenylimidazole)

[0071] <Preparation of film-like adhesive> (Examples 1 to 6 and Comparative Example 1) The adhesive varnish with the composition shown in Tables 1 and 2 was filtered through a 100-mesh filter and degassed under vacuum. The surface tension (pendant drop method) of the obtained adhesive varnish was 36 mN / m. As the base film, a polyethylene terephthalate (PET) film with a thickness of 38 μm and subjected to a release treatment was prepared, and the adhesive varnish after degassing under vacuum was applied onto the PET film. The application amount of the adhesive varnish was adjusted so that the thickness after drying would be 20 μm. By drying the applied adhesive varnish under the conditions shown in Tables 1 and 2, a film-like adhesive in the B-stage state was obtained. In the table, "wind" "yes" means that the adhesive varnish was dried under the condition that the wind speed flowing parallel to the upper surface of the coating film was 3 m / s or more, and "wind" "no" means that the adhesive varnish was dried under the condition that the wind speed flowing parallel to the upper surface of the coating film was substantially 0 m / s or more.

[0072] (Comparative Example 2) After producing a film-like adhesive in the same manner as in Example 1, the surface layer on the surface (first surface) side of the film-like adhesive was removed. That is, a range of about 0.6 μm in depth from the surface of the film-like adhesive was removed using a plasma treatment system PX-250 (manufactured by Nissho Electronics Co., Ltd.) so that the resin-rich region would be removed.

[0073] [Evaluation of copper ion permeation suppression effect] <Preparation of Solution A> 2.0 g of anhydrous copper(II) sulfate was dissolved in 1020 g of distilled water and stirred until the copper sulfate was completely dissolved to prepare an aqueous copper sulfate solution with a copper ion concentration of 500 mg / kg in terms of Cu element. The obtained aqueous copper sulfate solution was designated as Solution A.

[0074] <Preparation of Solution B> 1.0 g of anhydrous sodium sulfate was dissolved in 1000 g of distilled water and stirred until the sodium sulfate was completely dissolved. Then, 1000 g of N-methyl-2-pyrrolidone (NMP) was further added thereto and stirred. Thereafter, it was air-cooled until it reached room temperature to obtain an aqueous sodium sulfate solution. The obtained solution was designated as Solution B.

[0075] <Measurement of copper ion permeation time> After curing, the film-like adhesives (thickness: 10 μm) of the examples and comparative examples prepared above were each cut out into a circular shape with a diameter of about 3 cm. Next, two silicon packing sheets with a thickness of 1.5 mm, an outer diameter of about 3 cm, and an inner diameter of 1.8 cm were prepared. The film-like adhesive cut out into a circular shape was sandwiched between the two silicon packing sheets, and this was sandwiched between the flange portions of two glass cells with a volume of 50 mL and fixed with a rubber band.

[0076] Next, after injecting 50 g of Solution A into one glass cell, 50 g of Solution B was injected into the other glass cell. As carbon electrodes, Mars Carbon (manufactured by Staedtler GmbH & Co. KG, φ2 mm / 130 mm) was inserted into each cell. With the Solution A side as the anode and the Solution B side as the cathode, the anode was connected to a DC power supply (manufactured by A&D Co., Ltd., DC power supply device AD-9723D). Also, the cathode and the DC power supply were connected in series via an ammeter (manufactured by Sanwa Electric Instrument Co., Ltd., Degital multimeter PC-720M). At room temperature, a voltage was applied at 24.0 V, and the measurement of the current value was started after the application. The measurement time was set to 500 minutes, and the time for the current value to rise was taken as the copper ion permeation time. The rising time was defined as the time when the current value reached 1.0 μA. In this evaluation, it can be said that the slower the time for the current value to rise, the more the copper ion permeation is suppressed. Evaluation was carried out according to the following criteria. The results are shown in Table 1. A: Copper ion permeation time is 100 minutes or more. B: The copper ion permeation time is 60 minutes or more and less than 100 minutes. C: Copper ion permeation time is less than 60 minutes.

[0077] [Table 1]

[0078] [Table 2] [Explanation of symbols]

[0079] 1,2...film-like adhesive, 1c...cured product, 5...support film, 9,9a,9b...semiconductor chip, 10...support member, 11...wire, 12...encapsulant, 13...terminal, 100...adhesive film, 120...dicing and die bonding integrated film, D1...recess, F1...first surface, F2...second surface, L1...first adhesive layer (film-like adhesive), L2...second adhesive layer, L3...base film, R1,R2...region, S1...side portion.

Claims

1. A film-like adhesive having a single-layer structure, the film-like adhesive being composed of a thermosetting resin composition containing a filler and having a first surface and a second surface, the film adhesive has a region in the vicinity of the first surface, in which the filler content decreases from the second surface side toward the first surface side; A film-like adhesive having recesses formed on the first surface.

2. A film-like adhesive having a single-layer structure, the film-like adhesive being composed of a thermosetting resin composition containing a filler and having a first surface and a second surface, when the film-like adhesive is cured by heating, the film-like adhesive after thermal curing has a region in the vicinity of the first surface, in which the filler content decreases from the second surface side toward the first surface side, A film adhesive having recesses formed on the first surface.

3. 3. The film adhesive according to claim 1, wherein the thickness of said region is 2 μm or less.

4. 3. The film adhesive according to claim 1, wherein the ratio of the thickness of said region to the total thickness of said film adhesive is 0.3 to 25%.

5. The film adhesive according to claim 1 or 2, wherein the region is located at a depth from the first surface that is less than 2 μm.

6. 3. The film adhesive according to claim 1, wherein the filler content is 3 to 55 mass % based on the total mass of the resin composition.

7. The resin composition contains an acrylic rubber, The film-like adhesive according to claim 1 or 2, wherein the content of the acrylic rubber is 50 to 85 mass % based on the total mass of the resin composition.

8. The film adhesive according to claim 1 or 2, wherein the recesses extend in one or more directions within the plane of the first surface.

9. 3. The film adhesive according to claim 1, wherein the ratio of the area of ​​the recesses to the area of ​​the first surface in a plan view of the first surface is 10 to 70%.

10. The film-like adhesive according to claim 1 or 2; a substrate film in contact with the second surface of the film adhesive; An adhesive film comprising:

11. A first adhesive layer composed of the film-like adhesive according to claim 1 or 2; a second adhesive layer in contact with the second surface of the film adhesive; a base film in contact with the second adhesive layer; A dicing and die bonding integrated film comprising the above in this order.

12. A step of attaching a wafer to the first surface of the film-like adhesive in the dicing and die bonding integrated film according to claim 11; singulating the wafer and the film adhesive into a plurality of adhesive piece-attached chips; picking up the adhesive strip-attached chip from the second adhesive layer; Pressing the chip onto a substrate or another chip via the adhesive strip; A method for manufacturing a semiconductor device, comprising:

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