TWI806980B - Sealable adhesive sheet - Google Patents

Abstract

The adhesive sheet for packaging is used to package the electronic components mounted on the substrate, and at the same time adhere to the substrate. The adhesive sheet for packaging contains an adhesive composition. The amount of outgassing when the sealing adhesive sheet is heated at 150° C. for 30 minutes is 500 ppm or more relative to the sealing adhesive sheet before heating.

Description

Adhesive sheet for packaging

The present invention relates to an adhesive sheet for packaging.

Conventionally, it is known that an electronic device (electronic device) mounted on a substrate is packaged with a sealing resin sheet to manufacture an electronic device.

For example, a method for manufacturing an electronic device package has been proposed, in which a resin sheet for encapsulating an electronic device is laminated on an electronic device, and then the resin sheet for encapsulating an electronic device is cured to form a package (for example, refer to Japanese Patent Laid-Open No. 2017-98353).

However, the electronic device packaging sheet is used to package a semiconductor chip and then fix it on the surface of the substrate exposed from the semiconductor chip. Thereby, an electronic device package with excellent reliability can be manufactured. Therefore, the sheet for electronic device packaging requires good adhesion to the substrate.

The present invention provides an adhesive sheet for packaging that has excellent adhesiveness to a substrate.

The present invention (1) includes an adhesive sheet for encapsulation, which is an adhesive sheet for encapsulation that encapsulates electronic components mounted on a substrate, and is bonded to the substrate at the same time, wherein the adhesive composition is contained, and the amount of outgassing when the adhesive sheet for encapsulation is heated at 150° C. for 30 minutes is 500 ppm or more.

The present invention (2) includes the adhesive sheet for encapsulation as in (1), wherein the aforementioned adhesive composition contains a thermosetting component, an inorganic filler, and a coupling agent.

The present invention (3) includes the adhesive sheet for packaging according to (2), wherein the amount of the coupling agent blended is 1 part by mass or more relative to 100 parts by mass of the total amount of the thermosetting component and the inorganic filler.

The present invention (4) includes the adhesive sheet for encapsulation as in (2) or (3), wherein the aforementioned coupling agent is a silane coupling agent containing an epoxy group.

The present invention (5) includes the adhesive sheet for packaging according to any one of (1) to (4), which contains residual solvent, wherein the ratio of the residual solvent in the adhesive sheet for packaging is 5 ppm or more.

Since the adhesive sheet for packaging of the present invention contains an adhesive composition, it has excellent adhesiveness to the substrate.

Also, since the amount of outgassing generated when the adhesive sheet for packaging of the present invention is heated at 150° C. for 30 minutes is above the above-mentioned lower limit, the adhesiveness of the hardened product of the adhesive sheet for packaging can be improved by the sufficient amount of outgassing.

Therefore, this adhesive sheet for packaging has excellent reliability.

An adhesive sheet for semiconductor device packaging, which is one embodiment of the adhesive sheet for packaging of the present invention, will now be described with reference to FIGS. 1 to 2B.

This adhesive sheet 1 for semiconductor element encapsulation is an adhesive sheet for encapsulating and adhering to the substrate 2 while encapsulating a semiconductor element 3 (see FIG. 2A ) as an example of an electronic element to be mounted on a substrate 2 .

Also, the adhesive sheet 1 for semiconductor element packaging is a part used to manufacture the semiconductor element package assembly 4 (refer to FIG. 2B ) described later, not the semiconductor element package 4 itself. The adhesive sheet 1 for semiconductor element packaging does not include the semiconductor element 3 and the substrate 2 on which the semiconductor element 3 is mounted. Specifically, it is circulated as a separate part and is an industrially available device.

In addition, the adhesive sheet 1 for semiconductor element encapsulation is not the cured adhesive sheet 10 (see FIG. 2B ) (described later) after encapsulating the semiconductor element 3 , that is, it is a sheet before encapsulating the semiconductor element 3 .

As shown in FIG. 1 , the adhesive sheet 1 for semiconductor element encapsulation has a substantially flat plate shape (film shape) extending in a direction (surface direction) perpendicular to the thickness direction. Also, the semiconductor element packaging sheet 1 includes an adhesive surface 5 as an example of a surface located on one side in the thickness direction, and a first opposing surface 6 as an example of the other surface opposing the adhesive surface 5 in the thickness direction. Both the bonding surface 5 and the first opposing surface 6 have flat surfaces and are parallel to each other.

The bonding surface 5 is the surface (lower surface) on the other side in the thickness direction of the bonding sheet 1 for semiconductor element packaging. As shown in FIG.

On the other hand, the first facing surface 6 is a non-contact surface (one of the sides in the thickness direction) (upper surface) disposed opposite to the bonded surface 8 (described later) of the substrate 2 in the thickness direction when the adhesive sheet 1 for semiconductor element packaging is used to package the semiconductor element 3, without contacting the semiconductor element 3.

The sheet 1 for encapsulating a semiconductor element contains an adhesive composition. Specifically, the material of the adhesive sheet 1 for encapsulating semiconductor elements is an adhesive composition (encapsulating adhesive composition). Then the composition system contains, for example, thermosetting components, inorganic fillers and coupling agents.

The thermosetting component is an adhesive component that binds inorganic fillers in the adhesive sheet 1 (encapsulation composition) for semiconductor device encapsulation, and can increase the hardness of the adhesive composition by thermosetting, thereby enabling the adhesive composition to exhibit adhesive force. Preferable examples include epoxy-based thermosetting components (described later).

The thermosetting component includes, for example, a main ingredient (encapsulation resin), a curing agent, and a curing accelerator.

Examples of the main ingredient include epoxy resins, phenol resins, melamine resins, vinyl ester resins, cyanoester resins, maleimide resins, and silicone resins. As the main ingredient, epoxy resin is preferably used from the viewpoint of heat resistance and the like. If the main ingredient is an epoxy resin, the thermosetting component constitutes a curing agent (epoxy curing agent) and a curing accelerator (epoxy curing accelerator), which will be described later, and an epoxy thermosetting component.

Also, the main agent is a gas generating component that generates gas (a vaporized product of the main agent (preferably epoxy resin)) derived from the main agent when the semiconductor element encapsulating sheet 1 is heated to package the semiconductor element 3 .

Examples of the epoxy resin include bifunctional epoxy resins such as bisphenol A epoxy resins, bisphenol F epoxy resins, modified bisphenol A epoxy resins, modified bisphenol F epoxy resins, and biphenyl epoxy resins, and trifunctional or higher polyfunctional epoxy resins such as phenol novolac epoxy resins, cresol novolac epoxy resins, parahydroxyphenylmethane epoxy resins, tetraphenylolethane epoxy resins, and dicyclopentadiene epoxy resins. These epoxy resins can be used individually or in combination of 2 or more types.

Preferably, a bifunctional epoxy resin is used alone, and specifically, a bisphenol F-type epoxy resin is used alone.

The epoxy equivalent of the epoxy resin is, for example, 10 g/eq. or more, preferably 100 g/eq. or more; and, for example, 300 g/eq. or less, preferably 250 g/eq. or less.

The softening point of the main agent (preferably epoxy resin) is, for example, above 50°C, preferably above 70°C; and, for example, below 110°C, preferably below 90°C.

The proportion of the main agent (preferably epoxy resin) in the adhesive composition is, for example, 1% by mass or more, preferably 2% by mass or more; and, for example, 30% by mass or less, preferably 10% by mass or less. In addition, the proportion of the main ingredient (preferably epoxy resin) in the thermosetting component is, for example, 50% by mass or more, preferably 60% by mass or more; and, for example, 90% by mass or less, preferably 10% by mass or less.

If the ratio of the main agent (preferably epoxy resin) is more than the above-mentioned lower limit, a sufficient amount of gas originating from the main agent can be released to generate a desired amount of outgassing.

The curing agent is a component (preferably an epoxy resin curing agent) that cures the above-mentioned main ingredient by heating. Examples of the curing agent include phenol resins such as phenol novolac resins.

The ratio of the curing agent, if the main agent is an epoxy resin and the curing agent is a phenol resin, is adjusted so that the total of the hydroxyl groups in the phenol resin is, for example, 0.7 equivalents or more, preferably 0.9 equivalents or more, for example, 1.5 equivalents or less, preferably 1.2 equivalents or less, relative to 1 equivalent of epoxy groups in the epoxy resin. Specifically, the blending ratio of the curing agent is, for example, 30 parts by mass or more, preferably 50 parts by mass or more, and for example, 75 parts by mass or less, preferably 60 parts by mass or less with respect to 100 parts by mass of the main ingredient.

The hardening accelerator is a catalyst (thermosetting catalyst) that accelerates the hardening of the main agent by heating (preferably an epoxy resin hardening accelerator), and examples thereof include organophosphorus compounds; imidazole compounds such as 2-phenyl-4-methyl-5-hydroxymethylimidazole (2P4MHZ), and the like. Preferably, an imidazole compound is mentioned. The blending number of the hardening accelerator is, for example, 0.05 parts by mass or more with respect to 100 parts by mass of the main ingredient; and, for example, 5 parts by mass or less.

The inorganic filler is an inorganic particle used to increase the strength of the adhesive sheet 1 for encapsulating a semiconductor element and impart excellent toughness to the sheet 1 for encapsulating a semiconductor element. Examples of materials for the inorganic filler include inorganic compounds such as quartz glass, talc, silica, alumina, aluminum nitride, silicon nitride, and boron nitride. These can be used individually or in combination of 2 or more types. Preferably, silicon dioxide is used.

The shape of the inorganic filler is not particularly limited, and examples thereof include a substantially spherical shape, a substantially plate shape, a substantially needle shape, and an indeterminate shape. A slightly spherical shape is preferable.

The average value of the maximum length of the inorganic filler (average particle diameter if it is roughly spherical) M is, for example, 50 μm or less, preferably 20 μm or less, more preferably 10 μm or less; and, for example, 0.1 μm or more, preferably 0.5 μm or more. In addition, the average particle diameter M is obtained by D50 value (cumulative 50% median diameter) based on the particle size distribution obtained by the particle size distribution measurement method in the laser scattering method, for example.

In addition, the inorganic filler may include a first filler and a second filler having an average value M2 of a maximum length smaller than an average value M1 of a maximum length of the first filler.

The average value of the maximum length of the first filler (average particle diameter if it is approximately spherical) M1 is, for example, 1 μm or more, preferably 3 μm or more; and, for example, 50 μm or less, preferably 30 μm or less.

The average value of the maximum length of the second filler (average particle diameter if it is substantially spherical) M2 is, for example, less than 1 μm, preferably 0.8 μm or less; and, for example, 0.01 μm or more, preferably 0.1 μm or more.

The ratio (M1/M2) of the average maximum length of the first filler to the average maximum length of the second filler is, for example, 2 or more, preferably 5 or more; and, for example, 50 or less, preferably 20 or less.

The materials of the first filler and the second filler may be the same or different. Preferably, the materials of the first filler and the second filler are the same, specifically, silicon dioxide.

Furthermore, the surface of the inorganic filler can also be partially or completely treated with a silane coupling agent. Preferably, the combined use of the first filler without surface treatment and the second filler with surface treatment is used.

The proportion of the inorganic filler (if the first filler and the second filler are used together, their total amount) in the adhesive sheet 1 (adhesive composition) for semiconductor device packaging is, for example, 50% by mass or more, preferably more than 50% by mass, more preferably 55% by mass or more, more preferably 60% by mass or more; and, for example, 95% by mass or less, for example, 90% by mass or less, preferably 85% by mass or less, more preferably 75% by mass or less, and more preferably 70% by mass % or less, preferably less than 70% by mass.

When the ratio of the inorganic filler exceeds the above-mentioned lower limit, the toughness of the adhesive sheet 1 for semiconductor element encapsulation can be secured.

On the other hand, if the proportion of the inorganic filler is less than the above-mentioned upper limit, the embrittlement of the adhesive sheet 1 for semiconductor element encapsulation can be suppressed, and the semiconductor element 3 can be encapsulated reliably.

When the inorganic filler includes the above-mentioned first filler and second filler, the proportion of the first filler in the adhesive composition is, for example, 40 mass % or more, preferably more than 50 mass %; and, for example, 80 mass % or less, preferably 70 mass % or less.

When the inorganic filler includes the above-mentioned first filler and second filler, with respect to 100 parts by mass of the first filler, the number of blending parts of the second filler is, for example, 30 parts by mass or more, preferably 45 parts by mass or more, more preferably 50 parts by mass or more, more preferably more than 50 parts by mass; and, for example, less than 100 parts by mass, preferably 80 parts by mass or less, more preferably 70 parts by mass or less, and more preferably 60 parts by mass or less.

If the blending ratio of the second filler is higher than the above-mentioned lower limit or lower than the above-mentioned upper limit, then the larger gaps between the first fillers can be effectively filled by the second filler to obtain a semiconductor element packaging sheet 1 with excellent toughness, and even harden the adhesive sheet 10.

The coupling agent is a reactive component used to couple (form a chemical bond) the thermosetting component (especially the main component and the hardener) and the inorganic filler (preferably silicon dioxide) (the surface) to form a hardened adhesive sheet 10 with toughness. In addition, the coupling agent is also a gas derived from the coupling agent when the semiconductor element encapsulating sheet 1 is heated to package the semiconductor element 3 (the gas of the gasification of the coupling agent and the product (R' _4-n Si-OH _n ) generated by the hydrolysis reaction of the coupling agent (described later) (the gas of the following formula (1) for details of the chemical formula)) and the gas derived from the residual solvent (described later, preferably Alcohol derived from the hydrolysis reaction of the alkoxy group and the moisture in the air) (ROH) and other solvent gas) gas generating components. In addition, the above-mentioned gas derived from the coupling agent, the gas system derived from the residual solvent, and the gas derived from the main agent (the vaporized product of the epoxy resin) together constitute (include) the exhaust gas.

The coupling agent has at least two types of reactive groups in one molecule: a first reactive group that can react with the main agent, and a second reactive group that can react with the inorganic filler. As a 1st reactive group, an epoxy group, a vinyl group, a (meth)acryl group, an amine group, an isocyanate group, a mercapto group etc. are mentioned, for example. The 1st reactive group can be used individually or in combination. Preferably, an epoxy group is mentioned as a 1st reactive group. An alkoxy group etc. are mentioned as a 2nd reactive group.

Specifically, the coupling agent is, for example, a silane coupling agent.

A silane coupling agent is represented by following formula (1), for example.

R' _4-n Si-OR _n (1) In formula (1), R represents an alkyl group having 1 or more and 2 or less carbon atoms, such as a methyl group or an ethyl group. R' represents a group having a first reactive group (preferably an epoxy group described later). n represents, for example, an integer of 1 to 3, preferably an integer of 1 or 2.

Specifically, examples of the silane coupling agent include silane coupling agents having an epoxy group, a vinyl group, a (meth)acryl group, an amine group, an isocyanate group, a mercapto group, and the like as the first reactive group. Specifically, the silane coupling agent includes, for example, an epoxy group-containing silane coupling agent, a vinyl group-containing silane coupling agent, a (meth)acryl group-containing silane coupling agent, an amino group-containing silane coupling agent, an isocyanate group-containing silane coupling agent, and a mercapto group-containing silane coupling agent.

Examples of silane coupling agents containing epoxy groups include 3-glycidoxydialkyldialkoxysilanes such as 3-glycidoxypropylmethyldimethoxysilane and 3-glycidoxypropylmethyldiethoxysilane; for example, 3-glycidoxyalkyltrialkoxysilanes such as 3-glycidoxypropyltrimethoxysilane and 3-glycidoxypropyltriethoxysilane.

As a vinyl group-containing silane coupling agent, vinyltrimethoxysilane, vinyltriethoxysilane, etc. are mentioned, for example.

Examples of silane coupling agents containing (meth)acrylyl groups include silane coupling agents containing methacryl groups such as 3-methacryloxypropylmethyldimethoxysilane, 3-methacryloxypropyltrimethoxysilane, 3-methacryloxypropylmethyldiethoxysilane, and 3-methacryloxypropyltriethoxysilane. Acyl silane coupling agent, etc.

Examples of silane coupling agents containing amino groups include N-2-(aminoethyl)-3-aminopropylmethyldimethoxysilane, N-2-(aminoethyl)-3-aminopropyltrimethoxysilane, 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, 3-triethoxysilyl-N-(1,3-dimethyl-butylene)propylamine, N-phenyl-3-aminopropyltrimethoxysilane, Methoxysilane, etc.

As a silane coupling agent containing an isocyanate group, 3-isocyanate propyltriethoxysilane etc. are mentioned, for example.

Examples of the mercapto group-containing silane coupling agent include 3-mercaptopropylmethyldimethoxysilane and 3-mercaptopropyltrimethoxysilane.

As the coupling agent, preferably, an epoxy group-containing silane coupling agent is used, and more preferably, 3-glycidoxyalkyltrialkoxysilane is used.

The ratio of the coupling agent in the adhesive composition is, for example, 0.2% by mass or more, preferably 0.5% by mass or more, more preferably 1.0% by mass or more; and, for example, 10% by mass or less, preferably 5% by mass or less. In addition, with respect to 100 parts by mass of the total amount of the thermosetting component and the inorganic filler, the blending number of the coupling agent is, for example, 0.2 parts by mass or more, preferably 0.5 parts by mass or more, more preferably 1 part by mass or more; and, for example, 10 parts by mass or less, preferably 5 parts by mass or less.

If the ratio of the coupling agent and/or the number of blended parts is above the above-mentioned lower limit, the thermosetting component and the inorganic filler can be reliably coupled, and at the same time, a sufficient amount of gas derived from the coupling agent and gas derived from the residual solvent can be released, so that a desired amount of outgassing can occur.

On the other hand, if the ratio of the coupling agent and/or the number of blended parts is below the above upper limit, there is less risk of precipitation (bleeding) to the surface (adhesive surface 5 and first opposing surface 6) after the manufacture of the adhesive sheet 1 for semiconductor element encapsulation, and a stable varnish (described later) can be produced.

In addition, additives such as thermoplastic resins and pigments can also be added to the adhesive composition at an appropriate ratio.

The thermoplastic resin is a component that enhances the flexibility of the cured adhesive sheet 10 when heated.

Examples of thermoplastic resins include natural rubber, butyl rubber, isoprene rubber, chloroprene rubber, ethylene-vinyl acetate copolymer, ethylene-acrylic acid copolymer, ethylene-acrylate copolymer, polybutadiene resin, polycarbonate resin, thermoplastic polyimide resin, polyamide resin (6-nylon or 6,6-nylon, etc.), phenoxy resin, acrylic resin, saturated polyester resin (PET, etc.), polyamideimide resin, fluororesin, styrene - Isobutylene-styrene block copolymers, etc. These thermoplastic resins can be used individually or in combination of 2 or more types.

As a thermoplastic resin, an acrylic resin is mentioned preferably from a viewpoint of improving the dispersibility with a main ingredient (preferably an epoxy resin).

As the acrylic resin, for example, a carboxyl group-containing (meth)acrylate copolymer (preferably a carboxyl group-containing acrylate copolymer) obtained by polymerizing an alkyl (meth)acrylate having a straight-chain or branched alkyl group and other monomers (copolymerizable monomers) and the like.

Examples of the alkyl group include alkyl groups having 1 to 6 carbon atoms such as methyl, ethyl, propyl, isopropyl, n-butyl, tert-butyl, isobutyl, pentyl, and hexyl.

Examples of other monomers include carboxyl group-containing monomers such as acrylic acid, methacrylic acid, carboxyethyl acrylate, carboxypentyl acrylate, itaconic acid, maleic acid, fumaric acid, and crotonic acid.

The weight average molecular weight of the thermoplastic resin is, for example, 100,000 or more, preferably 300,000 or more; and, for example, 1 million or less, preferably 800,000 or less. In addition, the weight average molecular weight is measured based on the standard polystyrene conversion value by gel permeation chromatography (GPC).

The ratio of the thermoplastic resin (solid content ratio) is adjusted so as not to interfere with the thermosetting of the adhesive composition. Specifically, relative to the adhesive composition, it is, for example, 1% by mass or more, preferably 2% by mass or more, more preferably 3.5% by mass or more; and, for example, 10% by mass or less, preferably 5% by mass or less, more preferably 5% by mass or less.

In addition, thermoplastic resins can also be prepared by diluting them with appropriate solvents.

As a pigment, black pigments, such as carbon black, are mentioned, for example. The average particle diameter of the pigment is, for example, 0.001 μm or more and, for example, 1 μm or less. The ratio of the pigment to the adhesive composition is, for example, 0.1% by mass or more and, for example, 2% by mass or less.

To prepare an adhesive composition, a thermosetting component, an inorganic filler, a coupling agent, and additives as required are blended and mixed. Preferably, each of the above-mentioned components and a solvent are blended and mixed to prepare a varnish.

The solvent is not particularly limited, and examples thereof include ketones such as methyl ethyl ketone; aromatic solvents such as toluene; esters such as ethyl acetate; alcohols such as methanol and ethanol, and the like. Preferable examples include ketones.

Moreover, the solvent is preferably low molecular weight, specifically, its molecular weight is, for example, 300 or less, preferably 200 or less, more preferably 100 or less; and, for example, 20 or more, preferably 50 or more. When the molecular weight of the solvent is not more than the above upper limit and not less than the lower limit, the residual solvent-derived gas (solvent-derived gas) constituting part of the exhaust gas can be sufficiently generated to generate a desired amount of exhaust gas.

The number of blending parts of the solvent is set appropriately, relative to 100 parts by mass of the total amount of the above-mentioned components (the total amount of the thermosetting component, the inorganic filler, the silane coupling agent, and the additive) (the total amount of the so-called solid content), for example, 5 parts by mass or more, preferably 25 parts by mass or more, more preferably 75 parts by mass or more; and, for example, 1000 parts by mass or less, preferably 500 parts by mass or less. When the blending ratio of the solvent is more than the above lower limit, the residual solvent-derived gas (solvent-derived gas) constituting part of the exhaust gas can be sufficiently generated to generate a desired amount of exhaust gas. If the number of blending parts of a solvent is below the said upper limit, thick sheet|seat 1 for semiconductor element encapsulation can be manufactured simply by coating, drying, etc.

Next, a method of manufacturing the adhesive sheet 1 for semiconductor element packaging will be described.

To manufacture the adhesive sheet 1 for encapsulating semiconductor elements, for example, firstly, the above-mentioned varnish is prepared. Next, as shown in FIG. 1 , the varnish is applied to the first release sheet 15 and dried. Drying conditions are conditions that do not harden the thermosetting component (specifically, incomplete hardening), and remove most of the solvent (not the entire amount of the solvent). Specifically, the heating temperature is, for example, 40°C or higher, preferably 70°C or higher; and 130°C or lower, preferably 120°C or lower; and the heating time is, for example, 10 seconds or longer, preferably 1 minute or longer; and, for example, 15 minutes or less, preferably 10 minutes or less.

Thereby, the adhesive sheet 1 for semiconductor element packages is manufactured in the state supported by the 1st peeling sheet 15. Thereafter, the second release sheet 16 is arranged on the side opposite to the first release sheet 15 with respect to the adhesive sheet 1 for semiconductor element encapsulation. In other words, the adhesive sheet 1 for semiconductor element encapsulation is manufactured in the state sandwiched by the 1st peeling sheet 15 and the 2nd peeling sheet 16 in the thickness direction. The bonding surface 5 and the 1st opposing surface 6 of the bonding sheet 1 for semiconductor element packages contact the 1st peeling sheet 15 and the 2nd peeling sheet 16, respectively.

Each of the first release sheet 15 and the second release sheet 16 has flexibility and has a sheet shape extending in the surface direction. Examples of materials for the first release sheet 15 and the second release sheet 16 include resins such as polyethylene terephthalate and polyimide, metals such as stainless steel, and preferably resins. Moreover, the surface of the 1st peeling sheet 15 and the 2nd peeling sheet 16 (the contact surface which contacts the adhesive sheet 1 for semiconductor element encapsulation) may also be subjected to a peeling process. Each of the first release sheet 15 and the second release sheet 16 has a thickness of, for example, 1 μm or more, preferably 10 μm or more; and, for example, 1000 μm or less, preferably 500 μm or less.

In addition, instead of preparing a varnish, the adhesive sheet 1 for semiconductor element encapsulation may be produced from an adhesive composition (a composition substantially free of solvent) by kneading and extrusion. The 1st peeling sheet 15 and the 2nd peeling sheet 16 are arrange|positioned on the adhesive sheet 1 for semiconductor element encapsulation after extrusion.

It is preferable to prepare a varnish and apply it to form the sheet 1 for encapsulating a semiconductor element. If the semiconductor element encapsulating sheet 1 is formed of varnish, a desired amount of outgassing (in particular, gas derived from residual solvents derived from solvents) can be generated.

The thermosetting component in the adhesive sheet 1 for semiconductor element encapsulation is, for example, B-stage (semi-cured without complete curing). The B stage is a state where the thermosetting component is between the liquid A stage and the fully cured C stage. It is only slightly hardened and gelled, and the compressive elastic modulus is smaller than that of the C stage.

Thereby, the adhesive sheet 1 for semiconductor element packages is manufactured in the state which each of the adhesive surface 5 and the 1st opposing surface 6 is supported (protected) by the 1st peeling sheet 15 and the 2nd peeling sheet 16.

In the sheet 1 for encapsulating a semiconductor element, it is preferable to allow the solvent to remain. In other words, the sheet 1 for encapsulating a semiconductor element contains residual solvent. In the past, residual solvents were unfavorable components in the semiconductor element encapsulating sheet 1 , but in one embodiment, it is better to allow residual solvents instead.

Residual solvents include, for example, solvents added during varnish preparation, and alcohols (ROH such as methanol and ethanol (refer to the following formula (2)) produced by the hydrolysis reaction between the coupling agent and moisture in the air.

In addition, the hydrolysis reaction of the coupling agent is represented by the following formula (2).

R' _4-n Si-OR _n +nH ₂ O→R' _4-n Si-OH _n +nROH (2) In formula (2), R, R' and n are the same as those exemplified in formula (1).

The proportion of the residual solvent in the adhesive sheet 1 for encapsulating semiconductor elements is, for example, 5 ppm or more, preferably 10 ppm or more, more preferably 20 ppm or more, and more preferably 30 ppm or more on a mass basis; and, for example, 500 ppm or less, preferably 200 ppm or less.

If the ratio of the residual solvent is more than the above-mentioned lower limit, a desired amount of outgassing as described below can be generated, and the adhesiveness of the bonding surface 5 to the substrate 2 can be improved.

The ratio of the residual solvent was measured in terms of methyl ethyl ketone based on GC-MS, and the details will be described in Examples below.

Furthermore, with respect to the adhesive sheet 1 for semiconductor device packaging before heating, the amount of outgassing generated when the semiconductor device packaging sheet 1 is heated at 150° C. for 30 minutes is 500 ppm or more, preferably 750 ppm or more, more preferably 1,000 ppm or more, still more preferably 1,250 ppm or more, still more preferably 1,300 ppm or more, still more preferably 1,400 ppm or more, and still more preferably 1,500 ppm or more. and, for example, 10,000ppm or less, preferably 5,000ppm or less.

The above-mentioned heating conditions (heating at 150° C. for 30 minutes) are an example of the conditions used to completely harden the semiconductor element encapsulation sheet 1 to obtain the hardened adhesive sheet 10, specifically, it is also an example of the conditions used to obtain the cured adhesive sheet 10 adhered (contacted) to the substrate 2.

Traditionally, outgassing occurs when the hardened adhesive sheet 10 is obtained from the semiconductor device packaging sheet 1, and is an unfavorable component; however, in this embodiment, a large amount of outgassing needs to be generated instead.

Exhaust is an organic gas with a low molecular weight (for example, 300 or less, preferably 200 or less; and, for example, 20 or more, preferably 50 or more) generated by the semiconductor element packaging sheet 1 (specifically, the sheet or the hardening and bonding sheet 10 that is transferred from the semiconductor element packaging sheet 1 to the hardening and bonding sheet 10) under the above-mentioned heating conditions (specifically, the heating conditions for obtaining the hardening and bonding sheet 10).

Specifically, the exhaust gas includes, for example, the gas derived from the main agent, the gas derived from the coupling agent, the gas derived from the residual solvent (solvent gas derived from the residual solvent), and the like.

Exhaust gas is measured by purging and gas-collecting gas chromatography, and its detailed conditions are described in detail in the examples described later.

The thickness of the adhesive sheet 1 for semiconductor element packaging is not specifically limited, For example, it is 100 micrometers or more; Moreover, it is, for example, 2000 micrometers or less.

Next, a method for manufacturing a semiconductor element package 4 by packaging a semiconductor element 3 using the adhesive sheet 1 for semiconductor element packaging will be described.

The method for manufacturing the semiconductor element package 4 is provided with: the step of preparing the semiconductor element 3 (refer to FIG. 2A); the step of preparing the adhesive sheet 1 for semiconductor element packaging (refer to FIG. 1 and FIG. 2A);

In this method, as shown in FIG. 2A, first, a semiconductor element 3 is prepared.

It does not specifically limit as the semiconductor element 3, Various semiconductor elements are mentioned. Also, the semiconductor element 3 has, for example, a substantially flat plate shape extending in the surface direction. On one surface (lower surface) in the thickness direction of the semiconductor element 3, a plurality of terminals (not shown) arranged at intervals in the surface direction are provided.

The semiconductor element 3 is mounted on the adhered surface 8 (upper surface) of the substrate 2 (described later). Specifically, the semiconductor element 3 is, for example, flip-chip mounted on the substrate 2 via the above-mentioned terminals.

The substrate 2 is a construction substrate having a substantially flat shape extending in the surface direction. In addition, the substrate 2 has a bonded surface 8 (upper surface) on which the semiconductor element 3 is mounted, and a second opposing surface 9 arranged at a distance from the bonded surface 8 in the thickness direction.

The adhered surface 8 is a surface bonded to the bonding surface 5 of the sheet 10 through contact hardening, and has a plane along the surface direction. Furthermore, the adhered surface 8 is a mounting surface on which the semiconductor elements 3 are mounted, and has a size to surround a plurality of semiconductor elements 3 . In other words, the bonded surface 8 of the substrate 2 has an overlapping region 11 overlapping with the semiconductor element 3 in a plan view, and a bonded region (exposed region) 12 that is not overlapped with the semiconductor element 3 but is exposed from the substrate 2 and is directly bonded to the hardened bonding sheet 10. The bonded surface 8 is provided with substrate terminals (not shown) corresponding to terminals (not shown) of the semiconductor element 3 in the overlapping region 11 . In addition, in FIGS. 2A and 2B , although not shown, the overlapping region 11 is arranged with a small gap between the lower surface of the semiconductor element 3 in the thickness direction.

The second facing surface 9 is parallel to the adhered surface 8 and has a plane along the surface direction.

In this method, as shown in FIG. 1 and FIG. 2A, an adhesive sheet 1 for semiconductor element packaging is prepared. Specifically, as shown by arrows and phantom lines in FIG. 1 , the first peeling sheet 15 is peeled from the bonding surface 5 of the bonding sheet 1 for semiconductor element encapsulation.

As shown by the arrows in FIG. 2A and FIG. 2B , thereafter, the semiconductor element packaging adhesive sheet 1 is disposed on the semiconductor element 3 in such a manner that the adhesive surface 5 contacts the other surface (upper surface) of the semiconductor element 3 in the thickness direction.

As shown in FIG. 2B , next, the semiconductor element 3 is encapsulated by the adhesive sheet 1 for semiconductor element encapsulation.

For example, the semiconductor element 3 is packaged with the adhesive sheet 1 for semiconductor element encapsulation by heating and pressing the adhesive sheet 1 for semiconductor element encapsulation using a plate press (not shown) having a lower plate and an upper plate.

In addition, by the above heating, the adhesive sheet 1 for semiconductor device packaging is thermally hardened. Specifically, after temporarily softening, the adhesive composition of the adhesive sheet 1 for semiconductor element encapsulation is completely hardened (C-staged).

The heating condition is a condition to completely harden the adhesive composition. Specifically, the heating temperature is, for example, 85°C or higher, preferably 100°C or higher; and, for example, 125°C or lower, preferably 110°C or lower. The heating time is, for example, 10 minutes or more, preferably 30 minutes or more; and, for example, 300 minutes or less, preferably 180 minutes or less. The pressure is not particularly limited, and is, for example, 0.1 MPa or more, preferably 0.5 MPa or more; and, for example, 10 MPa or less, preferably 5 MPa or less.

The adhesive sheet 1 for semiconductor device encapsulation is temporarily softened to embed the semiconductor device 3 . In other words, the semiconductor element 3 is embedded by the adhesive sheet 1 for semiconductor element packaging.

The bonding surface 5 of the bonding sheet 1 for semiconductor element packaging covers the upper surface and peripheral side surfaces of the semiconductor element 3 and touches the bonded region 12 of the bonded surface 8 .

Thereby, the semiconductor element 3 is encapsulated by the adhesive sheet 1 for semiconductor element encapsulation. In addition, the bonded region 12 of the substrate 2 is in contact with (closely bonded to) the bonding sheet 1 for semiconductor element packaging.

In addition, the adhesive sheet 1 for semiconductor device packaging that has packaged the semiconductor device 3 and is in contact with the bonded region 12 of the substrate 2 has been thermally cured (completely cured) (stage C) by heating. Therefore, the adhesive sheet 1 for semiconductor element packaging becomes the hardened adhesive sheet 10 . The hardened adhesive sheet 10 is a cured product of the adhesive sheet 1 for encapsulating semiconductor elements.

After the adhesive composition of the above-mentioned adhesive sheet 1 for encapsulating semiconductor elements is completely cured, the adhesive sheet 10 exhibits adhesive force to the substrate 2 and the semiconductor element 3 after hardening.

As shown by the arrows in FIG. 2B , thereafter, the second peeling sheet 16 is peeled from the first opposing surface 6 of the cured adhesive sheet 10 . In other words, the first opposing surface 6 is exposed.

Thereby, the semiconductor element package 4 (hardened adhesive structure 20) provided with the board|substrate 2, the semiconductor element 3, and the hardened adhesive sheet 10 can be obtained.

Furthermore, since this semiconductor element encapsulation sheet 1 contains an adhesive composition, it is excellent in adhesiveness to the substrate 2 .

Also, since the amount of outgassing generated when the adhesive sheet 1 for semiconductor packaging is heated at 150° C. for 30 minutes is above the above-mentioned lower limit, the adhesiveness of the hardened adhesive sheet 10 to the substrate of the cured product of the adhesive sheet 1 for semiconductor device packaging can be improved by the sufficient amount of outgassing.

Therefore, it is presumed that the main reason is that the outgassing, specifically the gas originating from the main agent, the gas originating from the coupling agent, and the gas originating from the residual solvent, especially the gas originating from the main agent and the gas originating from the coupling agent perform surface treatment on the exposed area 12 of the mounting surface 8 of the substrate 2 (react with each other in the exposed area 12), thereby improving the adhesive force between the mounting surface 8 and the bonding surface 5.

＜Modifications＞ In the following modifications, the same members and steps as those in the above-mentioned first embodiment are assigned the same reference numerals, and detailed description thereof will be omitted. In addition, about each modification, unless otherwise specified, the same operation and effect as one embodiment can be exhibited. Moreover, one embodiment and a modified example can be combined suitably.

Although not shown in the figure, a plurality of semiconductor elements 3 can also be packaged by the adhesive sheet 1 for semiconductor element packaging. At this time, the cured adhesive sheet 10 in which the plurality of semiconductor elements 3 are packaged is cut by a cutter or the like.

In addition, in one embodiment, as an example of an adhesive sheet for packaging, a semiconductor element packaging adhesive sheet 1 is used to encapsulate a semiconductor element 3 as an example of an electronic element, but it is not limited thereto. For example, although not shown in the figure, it can also be an adhesive sheet for packaging other electronic elements. In this case, the electronic component can be packaged with the adhesive sheet for electronic component packaging to obtain an electronic component package. Example

Examples and comparative examples are shown below to describe the present invention more specifically. In addition, this invention is not limited at all by an Example and a comparative example. In addition, specific values such as blending ratios (proportions), physical properties, and parameters used in the following descriptions can be replaced with those described in the above-mentioned "embodiments", and correspond to the upper limits (values defined by "below" and "less than") or lower limits (values defined by "above" and "exceed") of their blending ratios (ratio), physical values, parameters, etc. in the descriptions.

The components, flakes, and the like used in Examples and Comparative Examples are shown below.

Epoxy resin: Nippon Steel Chemical Co., Ltd. YSLV-80XY (thermosetting component) (bisphenol F type epoxy resin (difunctional epoxy resin), epoxy equivalent 200g/eq. softening point 80°C) Curing agent: LVR-8210DL (thermosetting component) manufactured by Qunyei Chemical Co., Ltd. (novolac type phenolic resin, epoxy resin hardener, hydroxyl equivalent: 104 g/eq., softening point: 60°C) Hardening accelerator: Shikoku Chemical Industry Co., Ltd. 2PHZ-PW (thermosetting component) (2-phenyl-4,5-dihydroxymethylimidazole), epoxy resin hardening accelerator The first filler: FB-8SM (spherical fused silica powder (inorganic filler), average particle diameter: 15 μm) manufactured by Denka Corporation The second filler: an inorganic filler obtained by surface-treating SC220G-SMJ (average particle diameter: 0.5 μm) manufactured by Admatechs Co., Ltd. with 3-methacryloxypropyltrimethoxysilane (product name: KBM-503 manufactured by Shin-Etsu Chemical Co., Ltd.). An inorganic filler that is surface-treated with 1 part by mass of a silane coupling agent per 100 parts by mass of SC220G-SMJ.

Silane coupling agent: Shin-Etsu Chemical Co., Ltd. KBM-403 (coupling agent containing epoxy group) (3-glycidoxypropyltrimethoxysilane) Thermoplastic resin: Negami Industry Co., Ltd. HME-2006M, carboxyl group-containing acrylate copolymer, weight average molecular weight: 600,000, methyl ethyl ketone solution with a solid content concentration of 20% by mass Pigment: #20 (carbon black) manufactured by Mitsubishi Chemical Corporation Solvent: methyl ethyl ketone

Examples 1-4 and Comparative Examples 1-2 According to the blending formula recorded in Table 1, each component was dissolved and dispersed in methyl ethyl ketone to obtain a varnish.

After applying the varnish to the surface of the first peeling sheet 15, it was dried at 110° C. for 5 minutes. Thereby, the adhesive sheet 1 for semiconductor element packages with a thickness of 260 micrometers was produced. Thereafter, the second peeling sheet 16 is disposed on the first opposing surface 6 of the adhesive sheet 1 for semiconductor element encapsulation.

Thereby, each of the 1st peeling sheet 15 and the 2nd peeling sheet 16 is arrange|positioned on the bonding surface 5 and the 1st opposing surface 6, respectively, and the sheet|seat 1 for semiconductor element encapsulation in B stage is obtained.

[property] The following items were measured about the sheet|seat 1 for semiconductor element encapsulations. The results are described in Table 1.

(measurement of exhaust gas) A semiconductor element packaging sheet 1 having a size of 2 mm square was taken as a sample, this sample was put into a vial, and the mass of the sample was weighed. Next, the sample was heated at 150° C. for 30 minutes. During this period, the exhaust gas generated by the sample is collected into the cooled trapping tube, heated, and the mass of all the exhaust gas trapped is calculated based on the calibration curve with methyl ethyl ketone as the standard substance by means of a gas chromatograph (GC-MS) connected to a mass spectrometer. Next, the value obtained by dividing the calculated mass of the exhaust gas by the mass of the loaded semiconductor device encapsulating sheet 1 was obtained as the exhaust gas amount (unit: ppm) (dynamic headspace injection analysis method).

As the exhaust concentration device, MSTD-258M manufactured by GL Sciences was used.

As the trapping conditions of the exhaust gas, the flow rate of the chamber purge gas is 340 mL/min of _N2 gas, and the trapping time is 30 minutes.

As the analysis method, the GC-MS of the analysis device is used; as the analysis condition, the J&W capillary column DB-5MS is used as the column. After the column temperature is kept at 40°C for 3 minutes, the temperature is raised to 220°C at a heating rate of 9°C/min for 20 minutes, and then at a heating rate of 10°C/min, the temperature is raised to 300°C in 8 minutes and kept at 300°C for 3 minutes.

The temperature of the injection port was set at 250°C.

The carrier gas system uses He, the flow rate is 1.5mL/min, and the split ratio is 1:10.

MS analysis (mass analysis) was carried out by an electron ionization method using an analyzer (HP6890/5973-GC/MS manufactured by Agilent).

The temperature of the detector is taken as 230°C.

(Determination of residual solvent) The residual solvent in the sheet 1 for encapsulating a semiconductor element was measured by measurement in terms of methyl ethyl ketone by GC-MS.

[Evaluation of hardened adhesive sheet] The adhesiveness of the hardened adhesive sheet 10 was evaluated as follows (measurement of adhesive strength).

As shown in FIG. 3A (sectional view) and FIG. 3B (plan view), a substrate 2 composed of an alumina substrate with a length of 50 mm, a width of 10 mm, and a thickness of 200 μm was prepared. In addition, the substrate 2 is not used for constructing the semiconductor element 3 , but a test substrate for measuring bonding strength.

As shown by the imaginary lines and arrows in FIG. 3A , a semiconductor element packaging sheet 1 with a square size of 2 mm is prepared, and the bonding surface 5 of the semiconductor element packaging sheet 1 is attached to the surface of the substrate 2 . Next, it heated at 150 degreeC for 30 minutes. Thereby, the sheet|seat 1 for semiconductor element packages is fixed to the board|substrate 2 next. In this way, the cured bonded structure 20 having the semiconductor element encapsulating sheet 1 and the substrate 2 is produced.

Thereafter, the peel strength of the semiconductor element packaging sheet 1 and the substrate 2 of the hardened adhesive structure 20 was measured using a universal adhesive strength tester (Dage 4000 manufactured by Nordson Advanced Technology). As shown in FIG. 3A and FIG. 3B , the universal bond strength testing machine is equipped with a measuring device 30 that can move along the longitudinal direction. The gauge 30 has a pressing surface 31 (one side in the longitudinal direction) that can press the hardened adhesive sheet 10 on one side in the longitudinal direction.

In the measurement of the peeling strength, the gauge 30 was arranged at a distance (gap) of 50 μm from the surface of the substrate 2 on one of the longitudinal sides of the cured adhesive sheet 10 . Next, while moving the gauge 30 toward the hardened bonded sheet 10 and moving to the other side in the longitudinal direction, the pressing surface 31 of the gauge 30 is brought into contact with the side surface (part except the lower end) of the hardened bonded sheet 10, and then the gauge 30 is pressed (pressurized) toward the other longitudinal side.

Then, the strength (shear strength) when the hardened adhesive sheet 10 was peeled from the substrate 2 was obtained as the adhesive strength.

At the same time, when the hardened adhesive sheet 10 is peeled off from the substrate 2, in terms of failure mode, the case where the interface peeling between the hardened adhesive sheet 10 and the substrate 2 is rated as "○"; when the hardened adhesive sheet 10 is only slightly cohesively damaged, it is rated as "△"; when the hardened adhesive sheet 10 undergoes cohesive failure, it is rated as "×".

In Table 1, unless otherwise stated, the numerical values are blending parts.

In addition, the above-mentioned description is provided as an example embodiment of this invention, it is only an illustration, and it should not interpret it restrictively. Modifications of the present invention that are clear to those skilled in the art are included in the scope of claims described later.

1‧‧‧Adhesive sheet for semiconductor device packaging 2‧‧‧substrate 3‧‧‧Semiconductor components 4‧‧‧Semiconductor device package 5‧‧‧Joining 6‧‧‧The first facing surface 8‧‧‧Being connected 9‧‧‧The second facing surface 10‧‧‧hardened bonding sheet 11‧‧‧overlapping area 12‧‧‧Received area 15‧‧‧The first peeling sheet 16‧‧‧Second peeling sheet 20‧‧‧hardened bonding structure 30‧‧‧Measuring device 31‧‧‧press surface

Fig. 1 is a cross-sectional view of an adhesive sheet for encapsulating a semiconductor element, which is an embodiment of the adhesive sheet for encapsulating the present invention. 2A to FIG. 2B show the steps of using the adhesive sheet for semiconductor element packaging shown in FIG. 1 to package the semiconductor element and simultaneously attach it to the substrate to manufacture the semiconductor element package; FIG. 2A shows the steps of preparing the semiconductor element and the adhesive sheet for semiconductor element packaging respectively; FIG. 3A to 3B are schematic diagrams of adhesive strength measurement in the embodiment; FIG. 3A shows a cross-sectional view, and FIG. 3B shows a top view.

1‧‧‧Adhesive sheet for semiconductor device packaging

2‧‧‧substrate

3‧‧‧Semiconductor components

4‧‧‧Semiconductor device package

5‧‧‧Joining

6‧‧‧The first facing surface

8‧‧‧Being connected

9‧‧‧The second facing surface

10‧‧‧hardened bonding sheet

11‧‧‧overlapping area

12‧‧‧Received area

16‧‧‧Second peeling sheet

Claims (5)

An adhesive sheet for encapsulation, which is an adhesive sheet for encapsulating electronic components mounted on a substrate, and at the same time adhered to the aforementioned substrate, is characterized in that it contains an adhesive composition, and the aforementioned adhesive composition contains a thermosetting component, an inorganic filler of 55% by mass to 85% by mass, and a coupling agent of 0.5% by mass to 10% by mass. Compared to the adhesive sheet for encapsulation before heating, the amount of outgassing when the adhesive sheet for encapsulation is heated at 150°C for 30 minutes is: More than 500ppm. The adhesive sheet for packaging according to claim 1, wherein the amount of the aforementioned generation is 750 ppm or more. The adhesive sheet for packaging according to claim 2, wherein the amount of the coupling agent blended is 1 part by mass or more relative to 100 parts by mass of the total amount of the thermosetting component and the inorganic filler. The adhesive sheet for packaging according to claim 2, wherein the aforementioned coupling agent is a silane coupling agent containing an epoxy group. The adhesive sheet for packaging as claimed in claim 1, which contains residual solvent, Wherein, the proportion of the above-mentioned residual solvent in the adhesive sheet for packaging is more than 5 ppm.