JP2024010048A - Semiconductor device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a semiconductor device using a film-like adhesive which is excellent in adhesive force while sufficiently suppressing copper ion permeation in the adhesive.

SOLUTION: There is provided a semiconductor device. The semiconductor device includes a support member, a first semiconductor element bonded onto the support member by a first adhesive member, and a second semiconductor element bonded onto the first semiconductor element by a second adhesive member. The first adhesive member and the second adhesive member are cured products of the film-like adhesive. The film-like adhesive contains a thermosetting resin, a curing agent, acrylic rubber, and an inorganic filler. The content of the inorganic filler is 0.5-10 pts.mass with respect to 100 pts.mass of the total mass of the thermosetting resin, the curing agent, the acrylic rubber and the inorganic filler. The thickness of the film-like adhesive is 15 μm or less.

SELECTED DRAWING: Figure 7

COPYRIGHT: (C)2024,JPO&INPIT

Description

The present invention relates to a film adhesive, an adhesive sheet, a semiconductor device, and a method for manufacturing the same.

2. Description of the Related Art In recent years, stacked MCPs (Multi Chip Packages) in which semiconductor elements (semiconductor chips) are stacked in multiple stages have become popular, and are installed as memory semiconductor packages for mobile phones, mobile audio devices, and the like. Furthermore, as mobile phones and the like become more multifunctional, semiconductor packages are becoming faster, more dense, more highly integrated, and so on. Along with this, speeding up has been achieved by using copper as a wiring material for semiconductor chip circuits. In addition, lead frames made of copper are being used from the viewpoint of improving the reliability of connections to complex mounting boards and promoting heat dissipation from semiconductor packages.

However, copper has the characteristic of being easily corroded, and from the perspective of cost reduction, the coating materials used to ensure the insulation of the circuit surface are also becoming simpler, so the electrical characteristics of the semiconductor package cannot be guaranteed. It tends to be difficult to do. In particular, in a semiconductor package in which semiconductor chips are stacked in multiple layers, copper ions generated due to corrosion move inside the adhesive, which tends to cause electrical signal loss within the semiconductor chip or between semiconductor chips.

In addition, from the viewpoint of high functionality, semiconductor elements are often connected to complex mounting boards, and lead frames made of copper tend to be preferred in order to improve connection reliability. Even in such a case, loss of electrical signals due to copper ions generated from the lead frame may pose a problem.

Furthermore, in a semiconductor package using a member made of copper, there is a high possibility that copper ions are generated from the member, causing electrical problems, and sufficient HAST resistance may not be obtained.

In order to prevent loss of electrical signals, adhesives that capture copper ions generated within semiconductor packages are being studied. For example, Patent Document 1 describes a thermoplastic resin having an epoxy group and no carboxyl group, and a heterocyclic compound containing a tertiary nitrogen atom in a ring atom, which forms a complex with a cation. An adhesive sheet for manufacturing semiconductor devices having an organic complex-forming compound is disclosed.

However, conventional adhesives are not sufficient in terms of suppression of copper ion permeation within the adhesive and adhesive strength, and there is still room for improvement.

JP2013-026566A

Therefore, the main object of the present invention is to provide a film adhesive which has excellent adhesive strength while sufficiently suppressing copper ion permeation within the adhesive.

The inventors of the present invention have conducted extensive studies and found that by controlling the content of inorganic filler in a film adhesive within a specific range, it is possible to sufficiently suppress copper ion permeation within the adhesive while also achieving superior adhesive strength. This discovery led to the completion of the present invention.

One aspect of the present invention is a film adhesive for bonding a semiconductor element and a support member on which the semiconductor element is mounted, the film adhesive comprising a thermosetting resin, a curing agent, and an acrylic rubber. , an inorganic filler, the content of the inorganic filler is 0.5 to 10 parts by mass with respect to 100 parts by mass of the total mass of the thermosetting resin, curing agent, acrylic rubber, and inorganic filler, and the film To provide a film-like adhesive having a thickness of 15 μm or less.

The content of the inorganic filler is 0.5 to 10 parts by mass based on 100 parts by mass of the total mass of the thermosetting resin, curing agent, acrylic rubber, and inorganic filler. When the content of the inorganic filler is 0.5 parts by mass or more, the film adhesive tends to be excellent in terms of adhesive strength, wafer adhesion, elastic modulus, and bulk strength. When the content of the inorganic filler is 10 parts by mass or less, permeation of copper ions within the adhesive is sufficiently suppressed, and the appearance of the coated surface and embeddability also tend to be excellent.

In another aspect, the present invention provides an adhesive sheet comprising a base material and the above-described film adhesive provided on one surface of the base material. The base material may be a dicing tape.

In another aspect, the present invention includes a semiconductor element, a support member on which the semiconductor element is mounted, and an adhesive member provided between the semiconductor element and the support member to adhere the semiconductor element and the support member, the adhesive member being , provides a semiconductor device which is a cured product of the above-mentioned film adhesive. The support member may include a member made of copper.

In another aspect, the present invention provides a method for manufacturing a semiconductor device, which includes a step of bonding a semiconductor element and a support member using the above-described film adhesive.

In another aspect, the present invention provides a step of attaching a film adhesive of the above-described adhesive sheet to a semiconductor wafer, and cutting the semiconductor wafer to which the film adhesive is attached, thereby dividing the semiconductor wafer into a plurality of pieces. Provided is a method for manufacturing a semiconductor device, which includes a step of manufacturing a semiconductor element with a film-like adhesive attached thereto, and a step of adhering the semiconductor element with a film-like adhesive to a support member. The method for manufacturing a semiconductor device may further include a step of heating using a reflow oven.

According to the present invention, a film adhesive is provided which sufficiently suppresses permeation of copper ions within the adhesive and has excellent adhesive strength. Further, according to the present invention, an adhesive sheet and a semiconductor device using such a film adhesive are provided. Further, according to the present invention, a method for manufacturing a semiconductor device using a film adhesive or an adhesive sheet is provided.

FIG. 1 is a schematic cross-sectional view showing one embodiment of a film adhesive. FIG. 1 is a schematic cross-sectional view showing one embodiment of an adhesive sheet. FIG. 7 is a schematic cross-sectional view showing another embodiment of the adhesive sheet. FIG. 7 is a schematic cross-sectional view showing another embodiment of the adhesive sheet. FIG. 7 is a schematic cross-sectional view showing another embodiment of the adhesive sheet. FIG. 1 is a schematic cross-sectional view showing one embodiment of a semiconductor device. FIG. 3 is a schematic cross-sectional view showing another embodiment of a semiconductor device.

Embodiments of the present invention will be described below with appropriate reference to the drawings. However, the present invention is not limited to the following embodiments. In the following embodiments, the constituent elements (including steps, etc.) are not essential unless otherwise specified. The sizes of the components in each figure are conceptual, and the relative size relationships between the components are not limited to those shown in each figure.

The same applies to the numerical values and their ranges in this specification, and they do not limit the present invention. In this specification, a numerical range indicated using "-" indicates a range that includes the numerical values written before and after "-" as the minimum and maximum values, respectively. In the numerical ranges described step by step in this specification, the upper limit value or lower limit value described in one numerical range may be replaced with the upper limit value or lower limit value of another numerical range described step by step. good. Further, in the numerical ranges described in this specification, the upper limit or lower limit of the numerical range may be replaced with the value shown in the Examples.

As used herein, (meth)acrylate means acrylate or the corresponding methacrylate. The same applies to other similar expressions such as (meth)acryloyl group and (meth)acrylic copolymer.

A film adhesive according to one embodiment is a film adhesive for bonding a semiconductor element and a support member on which the semiconductor element is mounted, and the film adhesive includes (A) a thermosetting resin; Contains (B) a curing agent, (C) acrylic rubber, and (D) an inorganic filler, and the content of the inorganic filler is 100 mass of the total mass of the thermosetting resin, the curing agent, the acrylic rubber, and the inorganic filler. 0.5 to 10 parts by mass, and the thickness of the film adhesive is 15 μm or less.

The film adhesive is produced by molding an adhesive composition containing (A) a thermosetting resin, (B) a curing agent, (C) an acrylic rubber, and (D) an inorganic filler into a film. You can get it by doing this. The film-like adhesive and the adhesive composition may be in a semi-cured (B stage) state and may be in a fully cured (C stage) state after curing treatment.

Component (A): Thermosetting resin Component (A) may be an epoxy resin from the viewpoint of adhesiveness. The epoxy resin can be used without any particular restriction as long as it has an epoxy group in its molecule. Examples of the epoxy resin include bisphenol A epoxy resin, bisphenol F epoxy resin, bisphenol S epoxy resin, phenol novolac epoxy resin, cresol novolac epoxy resin, bisphenol A novolac epoxy resin, and bisphenol F novolac epoxy resin. , stilbene type epoxy resin, triazine skeleton-containing epoxy resin, fluorene skeleton-containing epoxy resin, triphenolmethane type epoxy resin, biphenyl type epoxy resin, xylylene type epoxy resin, biphenylaralkyl type epoxy resin, naphthalene type epoxy resin, 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 (A) may be a cresol novolac type epoxy resin, a bisphenol F type epoxy resin, or a bisphenol A type epoxy resin from the viewpoint of film tackiness, flexibility, etc.

The epoxy equivalent of the epoxy resin is not particularly limited, but may be 90 to 300 g/eq, 110 to 290 g/eq, or 110 to 290 g/eq. When the epoxy equivalent of the epoxy resin is within such a range, it tends to be possible to ensure fluidity while maintaining the bulk strength of the film adhesive.

Component (B): Curing agent Component (B) may be a phenol resin that can serve as a curing agent for epoxy resins. The phenol resin can be used without particular limitation as long as it has a phenolic hydroxyl group in its molecule. Examples of phenolic resins include 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, and formaldehyde. Novolak type phenol resin obtained by condensation or co-condensation with a compound having an aldehyde group under an acidic catalyst, allylated bisphenol A, allylated bisphenol F, allylated naphthalene diol, phenol novolac, phenols such as phenol and/or Alternatively, examples include phenol aralkyl resins and naphthol aralkyl resins synthesized from naphthols and dimethoxyparaxylene or bis(methoxymethyl)biphenyl. These may be used alone or in combination of two or more. Among these, the phenol resin may be a phenol aralkyl resin or a naphthol aralkyl resin.

The hydroxyl equivalent of the phenol resin may be 70 g/eq or more or 70 to 300 g/eq. When the hydroxyl equivalent of the phenol resin is 70 g/eq or more, the storage modulus of the film tends to be further improved, and when it is 300 g/eq or less, it is possible to prevent problems caused by foaming, outgassing, etc. .

The ratio of the epoxy equivalent of the epoxy resin to the hydroxyl equivalent of the phenol resin (epoxy equivalent of the epoxy resin/hydroxyl equivalent of the phenol resin) is 0.30/0.70 to 0.70/0.30 from the viewpoint of curability. , 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. It's good to be there. When the ratio is 0.30/0.70 or more, more sufficient curability tends to be obtained. When the ratio is 0.70/0.30 or less, the viscosity can be prevented from becoming too high, and more sufficient fluidity can be obtained.

The total content of component (A) and component (B) is 5 to 50 parts by mass per 100 parts by mass of the total mass of component (A), component (B), component (C), and component (D). parts, 10 to 40 parts by weight, or 15 to 30 parts by weight. When the total content of component (A) and component (B) is 5 parts by mass or more, the elastic modulus tends to improve due to crosslinking. When the total content of component (A) and component (B) is 50 parts by mass or less, film handling properties tend to be maintained.

(C) Component: Acrylic Rubber (C) Component is a rubber having as a main component a structural unit derived from a (meth)acrylic acid ester. The content of the structural unit derived from the (meth)acrylic acid ester in component (C) 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 the structural units. Component (C) may contain a structural unit 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. Component (C) may contain a structural unit derived from acrylonitrile within a range that satisfies the conditions of formula (1) described below, but it is possible to further suppress copper ion permeation within the adhesive. Component (C) may not contain a structural unit derived from acrylonitrile, since this is possible and provides better embedding properties.

In the infrared absorption spectrum of component (C), when the height of the absorption peak derived from the stretching vibration of the carbonyl group is P _CO and the height of the peak derived from the stretching vibration of the nitrile group is P _CN , P _CO and P _CN may satisfy the condition of the following formula (1).
P _CN /P _CO <0.070 (1)

Here, the carbonyl group is mainly derived from (meth)acrylic acid ester, which is a structural unit, and the nitrile group is mainly derived from acrylonitrile, which is a structural unit. The height of the absorption peak derived from the stretching vibration of the carbonyl group (P _CO ) and the height of the peak derived from the stretching vibration of the nitrile group (P _CN ) mean those defined in Examples.

A small P _CN /P _CO means that there are few structural units derived from acrylonitrile in the component (C). Therefore, the component (C) that does not contain a structural unit derived from acrylonitrile can theoretically satisfy the condition of formula (1).

P _CN /P _CO is less than 0.070, 0.065 or less, 0.060 or less, 0.055 or less, 0.050 or less, 0.040 or less, 0.030 or less, 0.020 or less, or It may be 0.010 or less. When P _CN /P _CO is less than 0.070, it may be possible to sufficiently suppress copper ion permeation within the adhesive. Furthermore, as the value of P _CN /P _CO decreases, copper ion permeation within the adhesive can be more effectively suppressed. Further, as the value of P _CN /P _CO decreases, the cohesive force of the component (C) decreases, and therefore the embeddability also tends to be better.

The glass transition temperature (Tg) of component (C) may be -50 to 50°C or -30 to 30°C. When the Tg of component (C) is -50°C or higher, it tends to be possible to prevent the adhesive from becoming too flexible. This makes it easier to cut the film adhesive during wafer dicing, making it possible to prevent the occurrence of burrs. When the Tg of the component (C) is 50° C. or lower, it tends to suppress a decrease in the flexibility of the adhesive. This tends to make it easier to fill in voids sufficiently when attaching the film adhesive to the wafer. Furthermore, it is possible to prevent chipping during dicing due to decreased adhesion of the wafer. Here, the glass transition temperature (Tg) means a value measured using a DSC (thermal differential scanning calorimeter) (for example, Thermo Plus 2, manufactured by Rigaku Co., Ltd.).

The weight average molecular weight (Mw) of component (C) may be from 100,000 to 3,000,000 or from 200,000 to 2,000,000. When the Mw of component (C) is within such a range, film formability, strength in film form, flexibility, tackiness, etc. can be appropriately controlled, as well as excellent reflow properties and improved embeddability. can do. Here, Mw means a value measured by gel permeation chromatography (GPC) and converted using a standard polystyrene calibration curve.

Commercially available products of component (C) include, for example, SG-70L, SG-P3, SG-708-6, WS-023 EK30, and SG-280 EK23 (all manufactured by Nagase ChemteX Corporation). Further, as a commercially available product of component (C) that does not contain a structural unit derived from acrylonitrile, for example, KH-CT-865 (manufactured by Hitachi Chemical Co., Ltd.) may be mentioned.

The content of component (C) is 50 to 95 parts by mass, 55 to 90 parts by mass based on 100 parts by mass of the total mass of component (A), component (B), component (C), and component (D). , or 60 to 85 parts by mass. When the content of component (C) is within this range, copper ion permeation within the adhesive tends to be more effectively suppressed.

(D) Component: Inorganic filler (D) Component includes, for example, aluminum hydroxide, magnesium hydroxide, calcium carbonate, magnesium carbonate, calcium silicate, magnesium silicate, calcium oxide, magnesium oxide, aluminum oxide, nitride Examples include aluminum, aluminum borate whiskers, boron nitride, and silica. These may be used alone or in combination of two or more. Among these, the component (D) may be silica from the viewpoint of adjusting the melt viscosity.

The average particle size of component (D) may be 0.01 to 1 μm, 0.01 to 0.8 μm, or 0.03 to 0.5 μm from the viewpoint of fluidity. Here, the average particle size means a value calculated from the BET specific surface area. As the average particle size of component (D) becomes smaller, the appearance of the coated surface tends to be further improved and the thin film coating properties tend to be further improved.

The shape of component (D) is not particularly limited, but may be spherical.

The content of component (D) is 0.5 to 10 parts by mass based on 100 parts by mass of the total mass of component (A), component (B), component (C), and component (D). When the content of component (D) is 0.5 parts by mass or more, the film adhesive tends to be excellent in adhesive strength, wafer adhesion strength, elastic modulus, and bulk strength. When the content of component (D) is 10 parts by mass or less, copper ion permeation within the adhesive is sufficiently suppressed, and the appearance of the coated surface and embeddability also tend to be excellent. The content of component (D) may be 1 part by mass or more, 3 parts by mass or more, or 5 parts by mass or more, and 10 parts by mass or less, 9 parts by mass or less, 8.5 parts by mass or less, or 8 parts by mass. or less.

The film adhesive (adhesive composition) may further contain (E) a coupling agent, (F) a curing accelerator, and the like.

Component (E): Coupling agent Component (E) may be a silane coupling agent. Examples of the silane coupling agent include γ-ureidopropyltriethoxysilane, γ-mercaptopropyltrimethoxysilane, 3-phenylaminopropyltrimethoxysilane, and 3-(2-aminoethyl)aminopropyltrimethoxysilane. It will be done. These may be used alone or in combination of two or more.

Component (F): Curing accelerator Component (F) is not particularly limited, and commonly used components can be used. Examples of the component (F) include imidazoles and derivatives thereof, 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 viewpoint of reactivity, the component (F) may be imidazoles and derivatives thereof.

Examples of 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.

The film adhesive (adhesive composition) may further contain other components. Examples of other components include pigments, ion scavengers, antioxidants, and the like.

The content of component (E), component (F), and other components is 0 parts by mass based on 100 parts by mass of the total mass of component (A), component (B), component (C), and component (D). It may be 30 parts by weight.

FIG. 1 is a schematic cross-sectional view showing one embodiment of a film adhesive. A film adhesive 1 (adhesive film) shown in FIG. 1 is an adhesive composition formed into a film. The film adhesive 1 may be in a semi-cured (B stage) state. Such a film adhesive 1 can be formed by applying an adhesive composition to a support film. When using an adhesive composition varnish (adhesive varnish), components (A), (B), (C), and (D), as well as other components added as necessary, are mixed in a solvent. The adhesive varnish is prepared by mixing or kneading the mixed solution, the adhesive varnish is applied to a support film, and the solvent is removed by heating and drying, thereby forming the film adhesive 1. .

The support film is not particularly limited as long as it can withstand the above heat drying, but examples include polyester film, polypropylene film, polyethylene terephthalate film, polyimide film, polyetherimide film, polyether naphthalate film, polymethylpentene film, etc. It may be. The support film may be a multilayer film made of a combination of two or more types, or the surface may be treated with a silicone-based, silica-based, or the like release agent. The thickness of the support film may be, for example, 10-200 μm or 20-170 μm.

Mixing or kneading can be carried out using a dispersing machine such as an ordinary stirrer, a sieve machine, a three-roll mill, a ball mill, etc., or by appropriately combining these dispersing machines.

The solvent used for preparing 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, dimethyl formamide, dimethyl acetamide, N-methyl pyrrolidone, toluene, and xylene. The solvent may be methyl ethyl ketone, cyclohexanone, etc. in terms of drying speed and cost.

As a method for applying the adhesive varnish to the support film, a known method can be used, such as a knife coating method, a roll coating method, a spray coating method, a gravure coating method, a bar coating method, a curtain coating method, etc. It will be done. The conditions for heat drying are not particularly limited as long as the solvent used is sufficiently volatilized, but drying can be carried out by heating at 50 to 150° C. for 1 to 30 minutes.

If the thickness of the film-like adhesive is 15 μm or less, the distance between the semiconductor element and the support member on which the semiconductor element is mounted becomes short, so that problems due to copper ions tend to occur more easily. Since the film-like adhesive according to this embodiment can sufficiently suppress permeation of copper ions within the adhesive, it is possible to reduce the thickness to 15 μm or less. The thickness of the film adhesive 1 may be 12 μm or less or 10 μm or less. The lower limit of the thickness of the film adhesive 1 is not particularly limited, but may be, for example, 1 μm or more.

In one embodiment, the copper ion permeation time of the film adhesive 1 in the semi-cured (B stage) state may be more than 260 minutes, 270 minutes or more, 280 minutes or more, 290 minutes or more, or 300 minutes or more. There may be. In other embodiments, the copper ion permeation time of the film adhesive 1 in the semi-cured (B stage) state may be more than 70 minutes, 75 minutes or more, or 80 minutes or more. When the copper ion permeation time is within this range, it is predicted that even if a defect such as insufficient curing occurs during the manufacture of a semiconductor device, defects due to copper ions will be less likely to occur.

In one embodiment, the adhesive force (die shear strength) of the film adhesive 1 (that is, the cured product of the film adhesive) in the C-stage state may be more than 0.5 MPa, and may be 0.8 MPa or more, or 1.5 MPa or more. It may be 0 MPa or more. In other embodiments, the adhesive strength (die shear strength) of the film adhesive in the C-stage state may be more than 1.5 MPa, 1.6 MPa or more, 1.7 MPa or more, or 1.8 MPa or more. There may be. When the adhesive strength is within this range, it is difficult to cause defects due to peeling during the production of semiconductor manufacturing equipment, and it is predicted that the higher the adhesive strength, the lower the probability of occurrence of defects due to peeling.

FIG. 2 is a schematic cross-sectional view showing one embodiment of an adhesive sheet. The adhesive sheet 100 shown in FIG. 2 includes a base material 2 and a film adhesive 1 provided on the base material 2. FIG. 3 is a schematic cross-sectional view showing another embodiment of the adhesive sheet. The adhesive sheet 110 shown in FIG. 3 includes a base material 2, a film adhesive 1 provided on the base material 2, and a cover film provided on the surface of the film adhesive 1 opposite to the base material 2. 3.

Although the base material 2 is not particularly limited, it may be a base film. The base film may be similar to the support film described above.

The cover film 3 is used to prevent damage or contamination of the film adhesive, and may be, for example, a polyethylene film, a polypropylene film, a film treated with a surface release agent, or the like. The thickness of the cover film 3 may be, for example, 15 to 200 μm or 70 to 170 μm.

The adhesive sheets 100 and 110 can be formed by applying an adhesive composition to a base film in the same manner as the method for forming the film adhesive described above. The method of applying the adhesive composition to the substrate 2 may be the same as the method of applying the adhesive composition to the support film described above.

The adhesive sheet 110 can be obtained by further laminating the cover film 3 on the film adhesive 1.

The adhesive sheets 100 and 110 may be formed using a film adhesive prepared in advance. In this case, the adhesive sheet 100 can be formed by laminating under predetermined conditions (for example, room temperature (20° C.) or heated state) using a roll laminator, a vacuum laminator, or the like. Since the adhesive sheet 100 can be manufactured continuously and has excellent efficiency, it may be formed using a roll laminator in a heated state.

Another embodiment of the adhesive sheet is a dicing/die bonding integrated adhesive sheet in which the base material 2 is a dicing tape. When a dicing/die bonding integrated adhesive sheet is used, the process of laminating the semiconductor wafer is performed only once, making it possible to improve work efficiency.

Examples of the dicing tape include plastic films such as polytetrafluoroethylene film, polyethylene terephthalate film, polyethylene film, polypropylene film, polymethylpentene film, and polyimide film. Further, the dicing tape may be subjected to surface treatments such as primer coating, UV treatment, corona discharge treatment, polishing treatment, etching treatment, etc., as necessary. The dicing tape may be adhesive. Such a dicing tape may be made of the above-mentioned plastic film with adhesive properties, or may be made of the above-mentioned plastic film with an adhesive layer provided on one side. The adhesive layer may be either a pressure-sensitive type or a radiation-curable type, and has sufficient adhesive strength to prevent the semiconductor elements from scattering during dicing, and has sufficient adhesive strength to prevent the semiconductor elements from being damaged during the subsequent pick-up process of the semiconductor elements. There are no particular restrictions on the material as long as it has low adhesive strength, and conventionally known materials can be used.

The thickness of the dicing tape may be 60 to 150 μm or 70 to 130 μm from the viewpoint of economy and film handling.

Examples of such a dicing/die bonding integrated adhesive sheet include one having the configuration shown in FIG. 4 and one having the configuration shown in FIG. 5. FIG. 4 is a schematic cross-sectional view showing another embodiment of the adhesive sheet. FIG. 5 is a schematic cross-sectional view showing another embodiment of the adhesive sheet. The adhesive sheet 120 shown in FIG. 4 includes a dicing tape 7, an adhesive layer 6, and a film adhesive 1 in this order. The adhesive sheet 130 shown in FIG. 5 includes a dicing tape 7 and a film adhesive 1 provided on the dicing tape 7.

The adhesive sheet 120 can be obtained, for example, by providing the adhesive layer 6 on the dicing tape 7 and further laminating the film adhesive 1 on the adhesive layer 6. The adhesive sheet 130 can be obtained, for example, by bonding the dicing tape 7 and the film adhesive 1 together.

The film adhesive and adhesive sheet may be used in the manufacture of semiconductor devices, and the film adhesive and dicing tape may be applied to a semiconductor wafer or a semiconductor element (semiconductor chip) that has already been cut into small pieces at 0°C or higher. After bonding at 90°C, a semiconductor element with a film-like adhesive is obtained by cutting with a rotary blade, a laser, or by stretching, and then the semiconductor element with a film-like adhesive is used as an organic substrate, a lead frame, or another semiconductor element. It may be used in manufacturing a semiconductor device including a step of adhering it thereon.

Examples of semiconductor wafers include single crystal silicon, polycrystalline silicon, various ceramics, and compound semiconductors such as gallium arsenide.

Film adhesives and adhesive sheets are used for semiconductor devices such as ICs and LSIs; lead frames such as 42 alloy lead frames and copper lead frames; plastic films such as polyimide resin and epoxy resin; polyimide resin on base materials such as glass nonwoven fabric, It can be used as a die bonding adhesive for bonding materials impregnated and hardened with plastics such as epoxy resin; supporting members for mounting semiconductors such as ceramics such as alumina.

Film adhesives and adhesive sheets are also suitably used as adhesives for bonding semiconductor elements together in a Stacked-PKG structure in which a plurality of semiconductor elements are stacked. In this case, one semiconductor element serves as a support member on which the semiconductor element is mounted.

Film adhesives and adhesive sheets are, for example, protective sheets for protecting the back side of semiconductor elements of flip-chip semiconductor devices, and sealing sheets between the surface of semiconductor elements of flip-chip semiconductor devices and adherends. It can also be used as a sealing sheet, etc.

A semiconductor device manufactured using a film adhesive will be specifically described using drawings. Note that semiconductor devices with various structures have been proposed in recent years, and the application of the film adhesive according to this embodiment is not limited to semiconductor devices with the structure described below.

FIG. 6 is a schematic cross-sectional view showing one embodiment of a semiconductor device. A semiconductor device 200 shown in FIG. 6 includes a semiconductor element 9, a support member 10 on which the semiconductor element 9 is mounted, and an adhesive member provided between the semiconductor element 9 and the support member 10 to adhere the semiconductor element 9 and the support member 10. (Cured product 1c of film adhesive). Connection terminals (not shown) of the semiconductor element 9 are electrically connected to external connection terminals (not shown) via wires 11 and sealed with a sealing material 12 .

FIG. 7 is a schematic cross-sectional view showing another embodiment of the semiconductor device. In the semiconductor device 210 shown in FIG. 7, the first-stage semiconductor element 9a is adhered to the support member 10 on which the terminal 13 is formed by an adhesive member (cured film-like adhesive 1c), and the first-stage semiconductor element 9a A second-stage semiconductor element 9b is further bonded thereon by an adhesive member (cured film adhesive 1c). Connection terminals (not shown) of the first-stage semiconductor element 9 a and the second-stage semiconductor element 9 b are electrically connected to external connection terminals via wires 11 and sealed with a sealing material 12 . In this way, the film adhesive according to this embodiment can also be suitably used for a semiconductor device having a structure in which a plurality of semiconductor elements are stacked.

The semiconductor device (semiconductor package) shown in FIGS. 6 and 7 is manufactured by, for example, interposing a film adhesive between a semiconductor element and a supporting member or between two semiconductor elements, and bonding them by heat and pressure. are bonded together, and then, if necessary, undergoes a wire bonding process, a sealing process with a sealing material, a heating melting process including reflow with solder, etc. The heating temperature in the thermocompression bonding process is usually 20 to 250°C, the load is usually 0.1 to 200N, and the heating time is usually 0.1 to 300 seconds.

As a method of interposing a film adhesive between a semiconductor element and a supporting member or between a semiconductor element and a semiconductor element, as described above, after preparing a semiconductor element with a film adhesive in advance, the supporting member or It may be a method of attaching it to a semiconductor element.

The support member may include a member made of copper. In the semiconductor device according to the present embodiment, since the semiconductor element and the support member are bonded together by the cured film adhesive 1c, there is no need to use a member made of copper as a component of the semiconductor device. However, the influence of copper ions generated from the member can be reduced, and the occurrence of electrical problems caused by copper ions can be sufficiently suppressed.

Here, examples of components made of copper include lead frames, wiring, wires, heat dissipation materials, etc., but the influence of copper ions can be reduced no matter which component is made of copper. It is.

Next, an embodiment of a method for manufacturing a semiconductor device using the dicing/die bonding integrated adhesive sheet shown in FIG. 4 will be described. Note that the method for manufacturing a semiconductor device using the integrated dicing and die bonding adhesive sheet is not limited to the method for manufacturing a semiconductor device described below.

First, a semiconductor wafer is pressure-bonded to the film adhesive 1 of the adhesive sheet 120 (dicing/die bonding integrated adhesive sheet), and is adhesively held and fixed (mounting step). This step may be performed while being pressed by a pressing means such as a pressure roll.

Next, the semiconductor wafer is diced. Thereby, the semiconductor wafer is cut into a predetermined size, and a plurality of individual film-like adhesive-attached semiconductor elements (semiconductor chips) are manufactured. Dicing can be performed, for example, from the circuit side of the semiconductor wafer according to a conventional method. In addition, in this step, for example, a cutting method called a full cut in which cuts are made to the dicing tape, a method in which half cuts are made in the semiconductor wafer and the semiconductor wafer is divided by cooling and pulling, a cutting method using a laser, etc. can be adopted. The dicing device used in this step is not particularly limited, and any conventionally known device can be used.

In order to peel off the semiconductor element adhesively fixed to the dicing/die bonding integrated adhesive sheet, the semiconductor element is picked up. The pickup method is not particularly limited, and various conventionally known methods can be employed. For example, there is a method in which each semiconductor element is pushed up from the dicing/die bonding integrated adhesive sheet side using a needle, and the pushed up semiconductor element is picked up by a pickup device.

If the adhesive layer is of a radiation (for example, ultraviolet) curing type, the pickup is performed after the adhesive layer is irradiated with radiation. This reduces the adhesive strength of the adhesive layer to the film adhesive, making it easier to peel off the semiconductor element. As a result, it becomes possible to pick up the semiconductor element without damaging it.

Next, the film-like adhesive-attached semiconductor element formed by dicing is adhered to a support member for mounting the semiconductor element via the film-like adhesive. Adhesion may be performed by crimping. The conditions for die bonding are not particularly limited and can be set as appropriate and necessary. Specifically, for example, die bonding can be carried out at a die bonding temperature of 80 to 160° C., a bonding load of 5 to 15 N, and a bonding time of 1 to 10 seconds.

If necessary, a step of thermally curing the film adhesive may be provided. By thermally curing the film adhesive bonding the supporting member and the semiconductor element in the above bonding step, it becomes possible to more firmly bond and fix the support member and the semiconductor element. When thermal curing is performed, pressure may be applied simultaneously for curing. The heating temperature in this step can be changed as appropriate depending on the constituent components of the film adhesive. The heating temperature may be, for example, 60 to 200°C. Note that the temperature or pressure may be changed in stages.

Next, a wire bonding step is performed in which the tips of the terminal portions (inner leads) of the support member are electrically connected to electrode pads on the semiconductor element using bonding wires. As the bonding wire, for example, a gold wire, an aluminum wire, a copper wire, etc. are used. The temperature during wire bonding may be in the range of 80 to 250°C or 80 to 220°C. The heating time may be from a few seconds to a few minutes. The wire connection may be performed in a heated state within the above-mentioned temperature range by using a combination of vibration energy generated by ultrasonic waves and compression energy generated by applied pressure.

Next, a sealing step is performed to seal the semiconductor element with a sealing resin. This step is performed to protect the semiconductor element or bonding wire mounted on the support member. This step is performed by molding the sealing resin with a mold. The sealing resin may be, for example, an epoxy resin. The heat and pressure during sealing embeds the substrate and the residue, making it possible to prevent separation due to air bubbles at the adhesive interface.

Next, in a post-curing process, the sealing resin that was insufficiently cured in the sealing process is completely cured. Even if the film adhesive is not thermally cured in the sealing process, adhesive fixation is possible by thermally curing the film adhesive at the same time as the sealing resin is cured in this process. The heating temperature in this step can be appropriately set depending on the type of sealing resin, and may be in the range of 165 to 185° C., for example, and the heating time may be about 0.5 to 8 hours.

Next, the semiconductor element with the film adhesive bonded to the support member is heated using a reflow oven. In this step, a resin-sealed semiconductor device may be surface-mounted on the support member. Examples of surface mounting methods include reflow soldering, in which solder is supplied onto a printed wiring board in advance, and then heated and melted with hot air or the like to perform soldering. Examples of the heating method include hot air reflow, infrared reflow, and the like. Moreover, the heating method may be a method of heating the whole body or a method of heating a local part. The heating temperature may be, for example, in the range of 240 to 280°C.

When semiconductor elements are laminated in multiple layers, thermal history such as wire bonding process increases, and bubbles present at the interface between the film adhesive and the semiconductor element can have a large effect on peeling. However, the use of a specific acrylic rubber in the film adhesive according to this embodiment tends to reduce cohesive force and improve embeddability. Therefore, it is difficult for air bubbles to be drawn into the semiconductor device, the air bubbles can be easily diffused in the sealing process, and separation due to air bubbles at the adhesive interface can be prevented.

The present invention will be specifically described below based on Examples, but the present invention is not limited thereto.

[Preparation of film adhesive]
(Example and comparative example)
<Preparation of adhesive varnish>
A composition consisting of (A) an epoxy resin as a thermosetting resin, (B) a phenol resin as a curing agent, and (D) an inorganic filler with the product name and composition ratio (unit: parts by mass) shown in Tables 1 and 2. Cyclohexanone was added to the mixture and mixed with stirring. To this, add (C) acrylic rubber shown in Tables 1 and 2 and stir, and then add (E) coupling agent and (F) curing accelerator shown in Tables 1 and 2 to ensure that each component is uniform. An adhesive varnish was prepared by stirring until . Note that the numerical values of component (C) and component (D) shown in Tables 1 and 2 mean parts by mass of solid content.

(A) Thermosetting resin (A1) YDCN-700-10 (trade name, manufactured by Nippon Steel & Sumikin Chemical Co., Ltd., o-cresol novolac type epoxy resin, epoxy equivalent: 209 g/eq)

(B) Curing agent (B1) HE-100C-30 (trade name, manufactured by Air Water Co., Ltd., phenylaralkyl phenol resin, hydroxyl equivalent: 174 g/eq, softening point 77°C)

(C) Acrylic rubber (C1) SG-P3 improved product (SG-P3 (trade name, manufactured by Nagase ChemteX Co., Ltd.) acrylic rubber, excluding structural units derived from acrylonitrile, weight average of acrylic rubber Molecular weight: 600,000, theoretical Tg of acrylic rubber: 12°C, P _CN /P _CO =0.001)
(C2) SG-P3 solvent-changed product (SG-P3 (trade name, manufactured by Nagase ChemteX Co., Ltd., methyl ethyl ketone solution of acrylic rubber) with a changed solvent, weight average molecular weight of acrylic rubber: 800,000, acrylic rubber Theoretical Tg: 12°C, P _CN /P _CO =0.070)

(Measurement of IR spectrum)
P _CN /P _CO of (C1) and (C2) was calculated by the following method. First, the transmitted IR spectra of (C1) and (C2) from which the solvent had been removed were measured by the KBr tablet method, and the vertical axis is the absorbance and the horizontal axis is the wave number (cm ^-1 ). For the measurement of the IR spectrum, FT-IR6300 (manufactured by JASCO Corporation, light source: high-intensity ceramic light source, detector: DLATGS) was used.

(Height of absorption peak derived from stretching vibration of carbonyl group P _CO )
The peak with the highest absorbance between 1670 cm ^-1 and 1860 cm ^-1 was defined as the peak point. The straight line between the two points 1670 cm ^-1 and 1860 cm ^-1 is taken as the baseline, and the point on this baseline that has the same wave number as the peak point is taken as the baseline point, and the difference in absorbance between the baseline point and the peak point is It was defined as the height of the absorption peak (P _CO ) derived from the stretching vibration of the carbonyl group.

(Height of peak derived from stretching vibration of nitrile group P _CN )
In the same IR spectrum as that used to determine P _CO , the peak with the highest absorbance between 2270 cm ⁻¹ and 2220 cm ⁻¹ was taken as the peak point. The straight line between the two points 2270 cm ^-1 and 2220 cm ^-1 is taken as the baseline, and the point on this baseline that has the same wave number as the peak point is taken as the baseline point, and the difference in absorbance between the baseline point and the peak point is It was defined as the peak height (P _CN ) derived from the stretching vibration of the nitrile group.

(D) Inorganic filler (D1) SC2050-HLG (trade name, manufactured by Admatex Co., Ltd., silica filler dispersion, average particle size 0.50 μm)

(E) Coupling agent (E1) A-189 (trade name, manufactured by Nippon Unicar Co., Ltd., γ-mercaptopropyltrimethoxysilane)
(E2) A-1160 (trade name, manufactured by Nippon Unicar Co., Ltd., γ-ureidopropyltriethoxysilane)

(F) Curing accelerator (F1) 2PZ-CN (trade name, manufactured by Shikoku Kasei Kogyo Co., Ltd., 1-cyanoethyl-2-phenylimidazole)

<Preparation of film adhesive>
The produced adhesive varnish was filtered through a 100 mesh filter and degassed under vacuum. A release-treated polyethylene terephthalate (PET) film having a thickness of 38 μm was prepared as a base film, and an adhesive varnish after vacuum defoaming was applied onto the PET film. The applied adhesive varnish was heated and dried in two steps, first at 90°C for 5 minutes and then at 130°C for 5 minutes, to obtain Examples 1-1 and 1-2 and Comparative Examples 1-1 and 1 in the B stage state. -2, Examples 2-1 and 2-2, and Comparative Examples 2-1 and 2-2 film adhesives were obtained. The film adhesive was adjusted to have a thickness of 10 μm depending on the amount of adhesive varnish applied.

[Measurement of copper ion permeation time]
<Preparation of liquid 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 a copper sulfate aqueous solution having a copper ion concentration of 500 mg/kg in terms of Cu element. The obtained copper sulfate aqueous solution was designated as A solution.

<Preparation of B solution>
1.0 g of anhydrous sodium sulfate was dissolved in 1000 g of distilled water and stirred until the sodium sulfate was completely dissolved. Further, 1000 g of N-methyl-2-pyrrolidone (NMP) was added to this and stirred. Thereafter, the mixture was air-cooled to room temperature to obtain an aqueous sodium sulfate solution. The obtained solution was designated as B solution.

<Measurement of copper ion permeation time>
The film adhesives (thickness: 10 μm) of Examples 1-1, 1-2 and Comparative Example 1-2 and Examples 2-1, 2-2 and Comparative Example 2-2 prepared above were each coated with a diameter of approximately Cut out a 3cm circle. Next, two silicone packing sheets having a thickness of 1.5 mm, an outer diameter of about 3 cm, and an inner diameter of 1.8 cm were prepared. A film adhesive cut out in a circular shape was sandwiched between two silicone packing sheets, and this was sandwiched between the flanges of two glass cells each having a volume of 50 mL, and fixed with a rubber band.

Next, 50 g of liquid A was injected into one glass cell, and then 50 g of liquid B was injected into the other glass cell. Mars Carbon (manufactured by Staedtler LLC, φ2 mm/130 mm) was inserted into each cell as a carbon electrode. The A liquid side was used as an anode and the B liquid side was used as a cathode, and the anode and a DC power source (manufactured by A&D Co., Ltd., DC power supply device AD-9723D) were connected. Further, the cathode and the DC power source were connected in series through an ammeter (Digital multimeter PC-720M, manufactured by Sanwa Denki Keiki Co., Ltd.). A voltage was applied at an applied voltage of 24.0 V at room temperature, and measurement of the current value was started after the voltage was applied. The measurement was carried out until the current value exceeded 15 μA, and the time when the current value reached 10 μA was defined as the copper ion permeation time. The results are shown in Tables 3 and 4. In this evaluation, it can be said that the longer the permeation time, the more the copper ion permeation is suppressed.

[Appearance evaluation of coated surface]
For the film adhesives of Examples 1-1, 1-2 and Comparative Example 1-2, Examples 2-1, 2-2, and Comparative Example 2-2, the appearance of the coated surface was evaluated, and foreign matter, missing particles, The presence of streaks etc. was visually confirmed. "A" indicates that no foreign matter, missing spots, streaks, etc. were confirmed; "B" indicates that foreign matter, missing spots, streaks, etc. were confirmed; "C" indicates that a large amount of foreign matter, missing spots, streaks, etc. were confirmed. rated it as. The results are shown in Tables 3 and 4.

[Evaluation of adhesive strength]
<Production of semiconductor device>
A dicing tape (manufactured by Hitachi Chemical Co., Ltd., thickness 110 μm) was prepared and prepared in Examples 1-1, 1-2 and Comparative Example 1-1, Examples 2-1, 2-2 and Comparative Example 2-1. A film adhesive (thickness: 10 μm) was attached to produce a dicing-die bonding integrated adhesive sheet comprising a dicing tape and a film adhesive. A 400 μm thick semiconductor wafer was laminated on the film adhesive side of a dicing-die bonding integrated adhesive sheet at a stage temperature of 70° C. to prepare a dicing sample.

The obtained dicing sample was cut using a fully automatic dicer DFD-6361 (manufactured by DISCO Co., Ltd.). The cutting was performed by a step cut method using two blades, and dicing blades ZH05-SD3500-N1-xx-DD and ZH05-SD4000-N1-xx-BB (both manufactured by DISCO Co., Ltd.) were used. The cutting conditions were a blade rotation speed of 4000 rpm, a cutting speed of 50 mm/sec, and a chip size of 7.5 mm x 7.5 mm. The first step of cutting was performed so that about 30 μm of the semiconductor wafer remained, and then the second step of cutting was performed so that a cut of about 20 μm was made in the dicing tape.

Subsequently, the semiconductor chip obtained by cutting was thermocompression bonded onto a solder resist (Taiyo Holdings Co., Ltd., trade name: AUS-308). The pressure bonding conditions were a temperature of 120° C., a time of 1 second, and a pressure of 0.1 MPa. Subsequently, the sample obtained by pressure bonding was placed in a dryer and cured at 170° C. for 1 hour. The semiconductor chip crimped to the solder resist is cured, and the semiconductor chip is hooked and pulled using a universal bond tester (manufactured by Nordson Advanced Technology Co., Ltd., product name: Series 4000) to perform die sharing after curing between the semiconductor chip and the solder resist. The strength was measured and evaluated as adhesive strength. The measurement conditions were a stage temperature of 250°C. The results are shown in Tables 5 and 6.

As shown in Tables 5 and 6, the film has an inorganic filler content of 0.5 to 10 parts by mass based on 100 parts by mass of the total mass of the thermosetting resin, curing agent, acrylic rubber, and inorganic filler. Compared to film adhesives that do not meet this requirement, the copper ion permeation time of the adhesive was longer and the adhesive strength was superior.

As described above, it was confirmed that the film adhesive of the present invention sufficiently suppresses copper ion permeation within the adhesive and has excellent adhesive strength.

DESCRIPTION OF SYMBOLS 1... Film adhesive, 2... Base material, 3... Cover film, 6... Adhesive layer, 7... Dicing tape, 9, 9a, 9b... Semiconductor element, 10... Supporting member, 11... Wire, 12... Sealing Material, 13... Terminal, 100, 110, 120, 130... Adhesive sheet, 200, 210... Semiconductor device.

Claims (2)

a support member;
a first semiconductor element adhered onto the support member by a first adhesive member;
a second semiconductor element adhered onto the first semiconductor element by a second adhesive member;
A semiconductor device having a structure in which semiconductor elements are stacked, comprising:
The first adhesive member and the second adhesive member are cured film adhesives,
The film adhesive contains a thermosetting resin, a curing agent, an acrylic rubber, and an inorganic filler,
The content of the inorganic filler is 0.5 to 10 parts by mass with respect to 100 parts by mass of the total mass of the thermosetting resin, the curing agent, the acrylic rubber, and the inorganic filler,
A semiconductor device, wherein the film adhesive has a thickness of 15 μm or less. The semiconductor device according to claim 1, wherein the support member includes a member made of copper.

Images