JPH10173102A - Semiconductor device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a semiconductor device which suppresses the thermal stress generated at reflow cracking and provides a superior reflow crack (package crack) resistance. SOLUTION: The device is a resin-sealed semiconductor device having a lead frame and a semiconductor element mounted on a die pad of the lead frame; the element is sealed with a resin hardened block. The die pad is covered with a silane coupling agent and the resin block is made of an epoxy resin compsn. contg. epoxy resin, phenol resin, hardening accelerator and partly cross-linked functional rubber grains.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a resin-sealed semiconductor device, and more particularly, to a die pad surface which is previously coated with a silane coupling agent.
The present invention relates to a semiconductor device formed of an epoxy resin composition containing partially crosslinked functional rubber particles.

[0002]

2. Description of the Related Art Among semiconductor devices using epoxy resin compositions, in recent years, quad flat packages (QFPs), low profile quad flat packages (LQFPs) and thin small outline packages (QFPs) have been increasingly used. thin small outline package: T
SOP) and other thin surface-mount packages are increasing, and reflow crack resistance during solder mounting on a circuit board is required.

The cause of the reflow crack is, for example, a peeling interface between the back surface of the die pad (the surface opposite to the semiconductor element mounting surface) and the cured resin when moisture absorbed by the cured resin constituting the package is reflowed by soldering. The cause may be that the cured resin does not withstand the thermal stress caused by the vaporization and expansion at the peeling interface between the semiconductor element and the cured resin, and the crack occurs without being able to withstand the strength.

Conventionally, as a method for improving the epoxy resin composition against the reflow crack, for example, Japanese Patent Application Laid-Open No.
As can be seen in JP-A-17474, the resin composition containing low-melting viscosity epoxy resin and phenolic resin curing agent as essential components is filled with a silica filler at a high density to greatly increase the water absorption of the cured resin composition. The method of reduction was the mainstream. However, in a situation where the package itself is becoming thinner and thinner, it is not sufficient to reduce the moisture absorption of only the epoxy resin composition forming the sealing resin, and there is a demand for even better reflow crack resistance.

On the other hand, as means for reducing thermal stress generated at the time of reflow crack, for example, Japanese Patent Publication No. 4-1583
As disclosed in Japanese Patent Application Publication No. 0-204, the use of crosslinked functional rubber particles has been proposed, but this method can alleviate the thermal stress to some extent, but does not provide reflow crack resistance. It was enough.

[0006]

SUMMARY OF THE INVENTION The present invention has been made in view of such circumstances, and an object of the present invention is to provide a semiconductor device having excellent reflow crack resistance during solder reflow.

[0007]

To achieve the above object, a semiconductor device according to the present invention comprises a lead frame and a semiconductor element mounted on a die pad of the lead frame sealed with a cured resin. A semiconductor device, wherein the die pad surface is coated with a silane coupling agent, and the cured resin is formed of an epoxy resin composition containing the following components (A) to (D). Take the configuration. (A) Epoxy resin. (B) a phenolic resin. (C) a curing accelerator. (D) Partially crosslinked functional rubber particles.

According to the present invention, for example, a separation interface between a surface opposite to a semiconductor element mounting surface of a die pad surface and a cured resin body, or a separation interface between a semiconductor element and a cured resin body, which causes a reflow crack, is mainly used as an adhesion interface. In order to reduce the thermal stress due to the vaporization and expansion of water vapor and to withstand the thermal stress generated at the minute peeling interface even if there is a minute peeling interface, the elongation of the resin cured body itself at a high temperature during solder reflow By paying attention to the ratio and improving this, the package crack resistance is improved overall. That is, the present invention covers the die pad surface of the lead frame with a silane coupling agent, and cures the epoxy resin cured product serving as the sealing resin portion with a special epoxy resin composition containing partially crosslinked functional rubber particles. It is a formed semiconductor device. For this reason, the adhesiveness at the interface between the die pad and the cured resin body made of the epoxy resin composition is improved, and the elongation characteristics of the cured resin body at a high temperature (for example, about 260 ° C.) during solder reflow are improved. Since the high temperature cohesive force is improved by the improvement, excellent solder package crack resistance, which cannot be obtained by the conventional method, is realized.

In particular, as the silane coupling agent,
By using at least one of the reactive silane compound represented by the general formula (1), and particularly, γ-glycidoxypropyltrimethoxysilane and γ-glycidoxypropylmethyldiethoxysilane, a resin cured product is obtained. The effect of further improving the adhesiveness at the interface between the die pad and the die pad is obtained.

[0010] Further, in the case where the coating treatment of the die pad surface with the silane coupling agent is performed by applying the silane coupling agent to the die pad surface and then heating it to 270 ° C or more, the method is more robust. An adhesive interface will result.

In the present invention, the die pad surface coated with the silane coupling agent is at least
It refers to both the surface on which the semiconductor element is mounted (hereinafter referred to as “die pad surface”) and the surface opposite to the surface on which the semiconductor element is mounted (hereinafter referred to as “die pad back surface”).

[0012]

Next, embodiments of the present invention will be described in detail.

The semiconductor device of the present invention is a semiconductor device in which a semiconductor element mounted on a die pad of a lead frame is sealed with a cured resin. The die pad surface is coated with a silane coupling agent, and the cured resin is formed of a specific epoxy resin composition.

Examples of the silane coupling agent used for coating the die pad surface include a reactive silane compound represented by the following general formula (1).

[0015]

(X) _{n + 1} -Si- (Y) _3-n (1) [In the above formula (1), X is a glycidyl group at the terminal,
A vinyl group, a methacryloyl group, a monovalent organic group having at least one functional group selected from the group consisting of an amino group and a mercapto group, Y is an alkoxyl group having 1 to 4 carbon atoms, May be included. N is 0, 1 or 2. ]

As the reactive silane compound represented by the above formula (1), specifically, vinyl tris (β-methoxyethoxy) silane, vinyl triethoxy silane, vinyl trimethoxy silane, γ-methacryloxypropyl trimethoxy Silane, β- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropylmethyldiethoxysilane, N-β (aminoethyl) γ-aminopropyltri Methoxysilane, N-β (aminoethyl) γ-aminopropylmethyldimethoxysilane, γ-
Aminopropyltriethoxysilane, N-phenyl-γ
A reactive silane compound comprising a functional group-containing hydrocarbon group and a hydrolyzable alkoxyl group represented by -aminopropyltrimethoxysilane, γ-mercaptopropyltrimethoxysilane and the like. Particularly, epoxysilanes such as γ-glycidoxypropyltrimethoxysilane and γ-glycidoxypropylmethyldiethoxysilane are suitable as an adhesion promoter between the cured resin and the die pad.

As a method of coating the die pad surface using a silane coupling agent, for example, the silane coupling agent is used as it is, or is diluted into an alcohol solution such as methanol or isopropanol, or an aqueous solution. A coating method may be used in which coating is performed on the die pad surface of the lead frame by a known method such as spray coating or dispense coating, followed by drying at room temperature or heating and drying. In particular, after a silane coupling agent is applied to the die pad surface, it is heated to 270 ° C. or higher, preferably 30 ° C.
When heated to a temperature range of 0 ° C. or higher, the silane coupling agent is hydrolyzed to generate silanol groups, so that the silanol groups easily form oxane bonds with the lead frame material, resulting in stronger adhesion. An interface is generated, which is preferable.

In the present invention, the material of the lead frame is not particularly limited, and may be a conventional one. When the material (including the die pad portion) of the lead frame is an iron-Ni alloy such as a 42 alloy or a 50 alloy during the coating process using the silane coupling agent, the coating after the application of the silane coupling agent is performed. The heating may be performed in the air, but when the lead frame material is a copper-based material, it is preferable to perform the heating operation in an inert gas such as a nitrogen gas.

As described above, the die pad surface coated with the silane coupling agent includes at least both the die pad surface and the die pad back surface. , Including the side surface of the die pad and a part of the suspension pin.

The epoxy resin composition for forming the cured resin of the semiconductor device of the present invention is an epoxy resin (component A).
And a phenolic resin (component B), a curing accelerator (component C), and partially cross-linked functional rubber particles (component D), which are usually powdered or pressed into tablets. Used as tablets.

The epoxy resin (component A) is not particularly limited, and various conventionally known epoxy resins can be used. Among them, a novolak type epoxy resin is preferably used. The novolak type epoxy resin includes an epoxy equivalent of 150 to 250 and a softening point of 50 to 1.
Examples thereof include a phenol novolak type epoxy resin at 30 ° C, a cresol novolak type epoxy resin having an epoxy equivalent of 180 to 210 and a softening point of 60 to 110 ° C. Further, together with the novolak type epoxy resin, if the glass transition temperature is within a range that does not cause molding problems,
4,4'-bis (2,3-epoxypropoxy) -3,
Biphenyl type epoxy resin such as 3 ′, 5,5′-tetramethylbiphenyl, bisphenol A type epoxy resin,
A bisphenol F type epoxy resin or the like can be used in combination.

The phenolic resin (component B) used together with the component A serves as a curing agent for the epoxy resin (component A), and is not particularly limited, and a conventionally known one can be used. For example, a phenol novolak resin having a hydroxyl equivalent of 100 to 200,
Examples include an alkyl-substituted phenol novolak resin and a phenol aralkyl resin.

The mixing ratio of the epoxy resin (A component) and the phenol resin (B component) is such that the hydroxyl group in the phenol resin is 0.8 to 1 equivalent of the epoxy group in the epoxy resin.
It is preferable to set so as to be 1.2 equivalents.

Examples of the curing accelerator (component C) used together with the above-mentioned components A and B include 1,8-diazabicyclo (5,4,0) -7-undecene (hereinafter abbreviated as "DBU"). But in addition to this,
4,6-tri (dimethylamino) methylphenol, 2
Any catalyst that serves as a catalyst for the curing reaction of a phenolic resin-cured epoxy resin such as -methylimidazole can be used in combination with DBU.

The amount of the curing accelerator (component C) is preferably set in the range of 0.1 to 10% by weight (hereinafter abbreviated as "%") of the entire epoxy resin composition, and particularly preferably 0. 0.5-5%.

The partially crosslinked functional rubber particles (component D) used together with the above components A to C include, for example, acrylonitrile-butadiene-crosslinkable monomer-reactive functional group monomer having a particle diameter of 1 nm to 1 μm. And the like.

Examples of the crosslinkable monomer include divinylbenzene, ethylene glycol diacrylate, ethylene glycol dimethacrylate, divinyl ether and the like.

The reactive functional group monomer includes:
Acrylic acid, methacrylic acid, maleic acid, fumaric acid, glycidyl acrylate, glycidyl methacrylate,
Examples thereof include 2,3-epoxy acrylate, 2,3-epoxy methacrylate, and allyl glycidyl ether.

As the partially crosslinked functional rubber particles (component (D)), it is particularly preferable to use epoxy group-containing rubber particles and carboxyl group-containing rubber particles, and these may be used alone or in combination.

In particular, as the epoxy group-containing rubber particles, it is preferable to use epoxy group-containing crosslinked acrylonitrile-butadiene rubber particles (epoxy group-containing crosslinked NBR particles), and specifically, glycidyl acrylate (or glycidyl methacrylate or 2,2). Crosslinked rubber-like copolymer particles of 3-epoxy acrylate or 2,3-epoxy methacrylate), acrylonitrile and butadiene are preferred.

Further, as the carboxyl group-containing rubber particles, carboxyl group-containing crosslinked acrylonitrile-butadiene rubber particles (carboxyl group-containing crosslinked NBR particles)
It is preferable to use acrylic acid (or methacrylic acid), acrylonitrile, and butadiene crosslinked rubber-like copolymer particles.

Then, the partially crosslinked functional rubber particles (D
Component) must have a partial cross-linked structure in advance, and the degree of cross-linking can be represented by, for example, measuring the gel fraction according to the following method and expressing the value. That is, first, the weight (W ₁ ) of a rubber particle to be measured is measured, and then the rubber particle is put into an organic solvent such as methyl ethyl ketone, methyl isobutyl ketone, N-methyl-2-pyrrolidone, and immersed at room temperature for 168 hours. I do. At this time, the non-gelled portion dissolves in the organic solvent. Next, after drying the insoluble matter at 120 ± 5 ° C. for 2 hours, the weight (W ₂ ) of the residue (gelled matter) is measured, and the gel fraction is calculated based on the following equation.

[0033]

## EQU1 ## Gel fraction (%) = (W ₂ / W ₁ ) × 100

The gel fraction, which is the degree of crosslinking, is preferably in the range of 50 to 100%. Particularly preferably, the gel fraction is 90 to 95%. That is, when the gel fraction is less than 50%, it becomes difficult to maintain elastic deformation of the cured composition at a high temperature such as a solder reflow temperature.

As described above, by using the above-mentioned partially crosslinked functional rubber particles as a component constituting the epoxy resin composition used in the present invention, the resistance to the thermal stress of the composition cured product at the solder reflow temperature is reduced. As a result, for example, as a result, the elongation of the resin cured body itself at a high temperature during solder reflow is improved, and the resin cured body can withstand the thermal stress generated at the minute peeling interface. The synergistic effect with the coating treatment of the silane coupling agent of (1) has a remarkable effect of improving package crack resistance.

However, for the purpose of improving the elongation of the cured resin itself at a high temperature, a liquid acrylonitrile-butadiene rubber containing a functional group which reacts with an epoxy group in the molecule, which is a conventional technique, may be used. Although these methods have been proposed, these methods have the problems that the glass transition temperature decreases, the electrical resistivity at high temperatures decreases, the dispersibility in the epoxy resin cured product is poor, and molding defects tend to occur during transfer molding. Occurs. The present inventors have found that the above effects can be obtained and that such problems can be solved by using partially crosslinked functional rubber particles as the D component, and have reached the present invention.

The blending amount of the partially crosslinked functional rubber particles (component D) is the total amount of the above components A to D (epoxy resin + phenol resin + curing accelerator + partially crosslinked functional rubber particles).
Is preferably set to 1 to 20%, particularly preferably 2 to 15%. That is, if the amount of the component D is less than 1%, it is difficult to improve the elongation of the resin cured product at a high temperature during solder reflow to obtain an excellent effect of improving reflow crack resistance. %, The melt viscosity of the composition during transfer molding increases, making it difficult to fill the cavity.

Further, in addition to the above-mentioned components A to D, the epoxy resin composition used in the present invention may contain, if necessary, conventional fillers such as inorganic fillers, flame retardants, coloring agents, ion trapping agents and various additives. Other components used from the above can be used as appropriate.

As the above-mentioned inorganic filler, there may be mentioned conventionally known ones. Among them, crystalline silica and fusible silica are preferably used, and in particular, crushed silica and spherical silica particles are used. And, the compounding amount is used in a proportion of 60 to 92%, more preferably in a proportion of 70 to 90% in the epoxy resin composition.

As the flame retardant, a compound such as a novolak type brominated epoxy resin, a bisphenol A type brominated epoxy resin, antimony trioxide, antimony pentoxide or the like is appropriately used alone or in combination of two or more.

As the colorant, carbon black and various pigments can be used.

It is also possible to use an ion trapping agent such as a hydrotalcite compound for the purpose of improving the moisture resistance reliability, and various silicone oils, silicone rubbers and synthetic rubbers for the purpose of further reducing the stress. Furthermore, various mold release agents such as montan waxes, carnauba waxes, polyethylene waxes, and stearic acid waxes, and other various coupling agents can be used.

The epoxy resin composition used in the present invention can be produced, for example, as follows.
That is, first, the above-mentioned partially crosslinked functional rubber particles (D component) are applied to two rolls heated to about 80 to 150 ° C.
It is charged together with the epoxy resin (A component) and the phenol resin (B component), and is sufficiently melt-kneaded. afterwards,
It is obtained by charging the remaining components and heating and kneading. The obtained epoxy resin composition may be cooled and pulverized and used as a powder, or may be further tableted and used.

The epoxy resin composition thus obtained is subjected to, for example, a molding step using a conventionally known low-pressure transfer molding machine. That is, a semiconductor element is mounted on a die pad previously coated with the above-mentioned silane coupling agent, and a lead frame electrically connected by a gold wire is placed in a mold of a transfer molding machine. Next, a desired resin-encapsulated semiconductor device is obtained by transfer molding generally under heating at 165 to 185 ° C.

The semiconductor device thus obtained has a substrate effect due to the synergistic effect of the effect of improving the adhesion at the interface between the die pad surface of the lead frame and the cured resin and the effect of improving the cohesive force of the cured resin itself. The package crack resistance at the time of solder mounting on the semiconductor device is dramatically improved as compared with the related art.

Next, examples will be described together with comparative examples.

(1) A case where epoxy group-containing partially crosslinked NBR copolymer particles are used as partially crosslinked functional rubber particles will be described.

[Preparation of Epoxy Resin Compositions a to e] Using the components shown in Table 1 below, epoxy resin compositions for sealing were prepared as follows. First, a cresol novolak type epoxy resin shown in Table 1 below and an epoxy group-containing partially crosslinked NBR were placed on two rolls heated to 95 ° C.
The copolymer particles were added at the mixing ratio shown in the same table and kneaded for 30 minutes to obtain the epoxy group-containing partially crosslinked NBR.
The copolymer particles were sufficiently dispersed. Further, the remaining components shown in Table 1 below were added thereto in the mixing ratio shown in the same table, and were heated and kneaded. After that, remove the kneaded material from the roll,
After cooling to room temperature, the mixture was pulverized and further compression-molded into a tablet through a tableting step.

[0049]

[Table 1]

The physical properties of each of the epoxy resin compositions a to e prepared as described above were measured according to the following methods. The results are shown in Table 2 below.

[175 ° C. Spiral Flow] Using a mold conforming to the EMMI standard, a molding temperature of 175 ° C. and a molding pressure of 7
It was measured at 0 kgf / cm ² .

[Elongation at 25 ° C. and 260 ° C.] JIS
K 6911.

[Strength at 25 ° C. and 260 ° C.] JIS
K 6911.

[Elastic modulus at 25 ° C. and 260 ° C.] JIS
K 6911.

[0055]

[Table 2]

[0056]

Example 1 A die pad of a 1.5 mm-thick 42-alloy lead frame for 80-pin QFP (size: 9.5 ×
A silane coupling agent shown in Table 3 below was brush-coated on the front and back surfaces of the die pad (9.5 mm), and heated at 300 ° C. for 1 hour in the air. Subsequently, the thickness 0.375
A silicon pellet having a size of 8 mm × 8 mm was die-bonded with a silver paste and dried at 180 ° C. for 30 minutes to bond and fix the silicon pellet on the surface of the die pad.

Subsequently, the lead frame on which the semiconductor chip is mounted is loaded into a molding die, and the lead frame is set to 70 kg / cm.
2 minutes at 175 ° C. in ² of mold pressure, a tablet made of the epoxy resin composition b was transfer molding, thickness 2.5 mm, 3.0 mm, 3 kinds of QFP resin-sealed package of 3.5 mm ( Size: 14 × 20
mm), and post-cured at 175 ° C. for 5 hours to obtain a target semiconductor device.

[0058]

Examples 2 to 6 The epoxy resin compositions for resin encapsulation were replaced with the epoxy resin compositions shown in Table 3 below. Further, the type of the silane coupling agent for coating the front and back surfaces of the die pad was changed to a silane coupling agent shown in Table 3 below. Otherwise in the same manner as in Example 1, a target semiconductor device was obtained.

[0059]

Comparative Example 1 The front and back surfaces of a die pad were not coated with a silane coupling agent. Except for this, the intended semiconductor device was obtained in the same manner as in Example 1, except that the epoxy resin composition a was used as the sealing resin.

[0060]

Comparative Example 2 The front and back surfaces of a die pad were coated with a silane coupling agent shown in Table 4 below. The epoxy resin composition for resin encapsulation was replaced with an epoxy resin composition (epoxy resin composition a) shown in Table 4 below. Otherwise in the same manner as in Example 1, a target semiconductor device was obtained.

[0061]

Comparative Example 3 The front and back surfaces of the die pad were not coated with a silane coupling agent. Except for this, the intended semiconductor device was obtained in the same manner as in Example 1, except that the epoxy resin composition c was used as the sealing resin.

The semiconductor devices thus obtained (packages having three different thicknesses in each of the examples and comparative examples) were dried at 120 ° C. for 24 hours, and then dried at 85 ° C.
/ 85% RH for 336 hours to allow saturated moisture absorption,
By dipping in a solder bath at 260 ° C. for 60 seconds, the presence or absence of occurrence of a package crack was visually checked. The results are shown in Tables 3 and 4 below.

[0063]

[Table 3]

[0064]

[Table 4]

From the results shown in Table 2, the epoxy resin compositions b to e containing the epoxy group-containing partially crosslinked NBR particles were added.
Indicates that elongation characteristics are improved as compared with the epoxy resin composition a in which the epoxy group-containing crosslinked NBR is not blended.

On the other hand, from the results in Tables 3 and 4, Comparative Example 1 using an epoxy resin composition in which the die pad surface was not coated with a silane coupling agent and in which no epoxy group-containing crosslinked NBR was blended was used. Then, package cracks occurred in all packages having different thicknesses. Further, Comparative Example 2 in which the die pad surface was simply coated with the silane coupling agent also provided substantially the same results as Comparative Example 1, indicating that the package crack resistance was poor. Further, Comparative Example 3 in which the die pad surface was not coated with a silane coupling agent and an epoxy resin composition containing partially crosslinked NBR particles containing an epoxy group was used as a sealing resin,
Package cracks did not occur in the packages having a thickness of 3.0 mm and 3.5 mm, but package cracks occurred in all the packages having a thickness of 2.5 mm.
Therefore, it is understood that the thin package does not have sufficient package crack resistance. On the other hand, examples using a lead frame having a die pad surface coated with a silane coupling agent and using an epoxy resin composition containing partially crosslinked NBR particles containing an epoxy group as a sealing resin have different thicknesses. No package cracks occurred in all of the packages. From this, it is clear that the package crack resistance is excellent.

(2) A case where carboxyl group-containing partially crosslinked NBR copolymer particles are used as partially crosslinked functional rubber particles will be described.

[Preparation of Epoxy Resin Compositions fi] Using the components shown in Table 5 below, an epoxy resin composition for sealing was prepared as follows. First, a cresol novolak type epoxy resin shown in Table 5 below and a carboxyl group-containing partially crosslinked N were added to two rolls heated to 95 ° C.
The BR copolymer particles were charged at the compounding ratio shown in the same table, and 30
By kneading for minutes, the carboxyl group-containing partially crosslinked NBR copolymer particles were sufficiently dispersed. Further, the remaining components shown in Table 5 below were added thereto in the mixing ratio shown in the same table, and were heated and kneaded. Thereafter, the kneaded product was taken out from the roll, cooled to room temperature, pulverized, and further compression-molded into a tablet by passing through a tableting step.

[0069]

[Table 5]

The physical properties of the epoxy resin compositions fi prepared as described above were measured in the same manner as described above. The results are shown in Table 6 below.

[0071]

[Table 6]

[0072]

Embodiment 7 A die pad of a 1.5 mm thick 80-pin QFP 42 alloy lead frame (size: 9.5 ×
A silane coupling agent shown in Table 7 below was brush-coated on the front and back surfaces of a die pad (9.5 mm), and heated in air at 300 ° C. for 1 hour. Subsequently, the thickness 0.375
A silicon pellet having a size of 8 mm × 8 mm was die-bonded with a silver paste and dried at 180 ° C. for 30 minutes to bond and fix the silicon pellet on the surface of the die pad.

Subsequently, the lead frame on which the semiconductor chip was mounted was loaded in a molding die, and the lead frame was set at 70 kg / cm.
2 minutes at 175 ° C. in ² of mold pressure, a tablet made of the epoxy resin composition f was transfer molding, thickness 2.5 mm, 3.0 mm, 3 kinds of QFP resin-sealed package of 3.5 mm ( Size: 14 × 20
mm), and post-cured at 175 ° C. for 5 hours to obtain a target semiconductor device.

[0074]

Examples 8 to 12 The epoxy resin compositions for resin encapsulation were replaced with the epoxy resin compositions shown in Table 7 below. Also,
The type of silane coupling agent for coating the front and back surfaces of the die pad was changed to a silane coupling agent shown in Table 7 below. Otherwise in the same manner as in Example 1, a target semiconductor device was obtained.

[0075]

Comparative Example 4 The front and back surfaces of the die pad were not coated with a silane coupling agent. Except for this, the intended semiconductor device was obtained in the same manner as in Example 1, except that the epoxy resin composition i was used as the sealing resin.

Each of the semiconductor devices thus obtained (three types of packages having different thicknesses for the example and the comparative example) was dried at 120 ° C. for 24 hours and then left at 85 ° C./85% RH for 336 hours. After that, the package was immersed in a solder bath at 260 ° C. for 60 seconds to visually check for the occurrence of package cracks. The results are shown in Tables 7 and 8 below.

[0077]

[Table 7]

[0078]

[Table 8]

From the results in Table 6 above, the epoxy resin compositions f to which the carboxyl group-containing partially crosslinked NBR particles were blended.
As for i, it is understood that the elongation property is improved as compared with the epoxy resin composition a in which the partially crosslinked NBR particles are not blended.

On the other hand, from the results in Tables 7 and 8, the die pad surface was not coated with a silane coupling agent, and an epoxy resin composition containing partially crosslinked NBR particles containing carboxyl groups was used as a sealing resin. In Comparative Example 4, package cracks did not occur in the packages having a thickness of 3.0 mm and 3.5 mm, but package cracks occurred in all the packages having a thickness of 2.5 mm. Therefore, it is understood that the thin package does not have sufficient package crack resistance. On the other hand, examples using a lead frame having a die pad surface coated with a silane coupling agent and using an epoxy resin composition containing carboxyl group-containing partially crosslinked NBR particles as a sealing resin have different thicknesses. No package cracks occurred in all of the packages. From this, it is clear that the package crack resistance is excellent.

[0081]

As described above, the present invention relates to a semiconductor device in which a lead frame and a semiconductor element mounted on a die pad of the lead frame are sealed with a cured resin. The resin cured product is coated with a silane coupling agent, and is formed of a special epoxy resin composition containing partially crosslinked functional rubber particles. For this reason, the adhesiveness of the interface between the die pad and the cured resin body made of the epoxy resin composition is improved,
In addition, the solder temperature of the resin cured body itself (for example, 260
Since the high temperature cohesive force is improved by improving the elongation characteristics at about (° C.), excellent solder package crack resistance, which cannot be obtained by the conventional method, is realized.

In particular, as the silane coupling agent,
By using at least one of the reactive silane compound represented by the above formula (1), in particular, γ-glycidoxypropyltrimethoxysilane and γ-glycidoxypropylmethyldiethoxysilane, a cured resin is obtained. The effect of further improving the adhesiveness at the interface of the die pad can be obtained.

Further, when the coating treatment of the die pad surface with the silane coupling agent is performed by applying the silane coupling agent to the die pad surface and then heating it to 270 ° C. or more, the solidification becomes even stronger. An adhesive interface will result.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁶ Identification code FI C08L 33:20 61:04)

Claims (10)

[Claims] 1. A semiconductor device comprising a lead frame and a semiconductor element mounted on a die pad of the lead frame sealed with a cured resin, wherein the die pad surface is coated with a silane coupling agent. Further, the semiconductor device is characterized in that the cured resin is formed of an epoxy resin composition containing the following components (A) to (D). (A) Epoxy resin. (B) a phenolic resin. (C) a curing accelerator. (D) Partially crosslinked functional rubber particles. 2. The semiconductor device according to claim 1, wherein the silane coupling agent is a reactive silane compound represented by the following general formula (1). (X) _{n + 1} -Si- (Y) _3-n (1) [In the above formula (1), X represents a glycidyl group at the terminal,
A vinyl group, a methacryloyl group, a monovalent organic group having at least one functional group selected from the group consisting of an amino group and a mercapto group, Y is an alkoxyl group having 1 to 4 carbon atoms, May be included. N is 0, 1 or 2. ] 3. The reactive silane compound represented by the general formula (1) is at least one of γ-glycidoxypropyltrimethoxysilane and γ-glycidoxypropylmethyldiethoxysilane. Semiconductor device. 4. The coating treatment of the die pad surface with the silane coupling agent is a coating treatment performed by applying a silane coupling agent to the die pad surface and heating the silane coupling agent to 270 ° C. or higher. The semiconductor device according to claim 1. 5. The semiconductor according to claim 1, wherein the partially crosslinked functional rubber particles as the component (D) are at least one of a carboxyl group-containing rubber particle and an epoxy group-containing rubber particle. apparatus. 6. The semiconductor device according to claim 5, wherein the carboxyl group-containing rubber particles are carboxyl group-containing crosslinked acrylonitrile-butadiene rubber particles. 7. The semiconductor device according to claim 5, wherein the epoxy group-containing rubber particles are epoxy group-containing crosslinked acrylonitrile-butadiene rubber particles. 8. The content of the partially crosslinked functional rubber particles as the component (D) is set to 1 to 20% by weight based on the total amount of the components (A) to (D). The semiconductor device according to any one of claims 1 to 7. 9. The curing accelerator as the component (C),
The semiconductor device according to claim 1, wherein the semiconductor device is 1,8-diazabicyclo (5,4,0) -7-undecene. 10. An epoxy resin composition for encapsulating a semiconductor, comprising the following components (A) to (D). (A) Epoxy resin. (B) a phenolic resin. (C) a curing accelerator. (D) Partially crosslinked functional rubber particles.