JPH03174745A - Semiconductor device - Google Patents

Abstract

PURPOSE:To improve stress reduction with no pretreatment before packaging to electronic appliances and with resistance to heating in soldered packaging by sealing a semiconductor chip with an epoxy resin composite which contains two specific kinds of components. CONSTITUTION:A semiconductor chip is sealed with an epoxy resin composite which contains an epoxy resin represented by formula I and a reaction product obtained by preliminary reaction of a silane compound represented by formula II with a phenol aralkyl resin represented by formula III. In formula I R1-R4 are alkyl groups of carbon number 1-4; in formula II X is a monovalent organic group whose terminal has at least one functional group selected from a group consisting of glycidyl group, amino group, and mercapto group, Y is an alkoxy group of carbon number 1-4, and n is 0.1 or 2; and in formula III m is a positive integer. This constitution makes the device excellent in bonding strength of a semiconductor chip and sealing resin, prevents package cracks under severe conditions in soldering packaging to provide excellent moistureproof reliability, and improves stress reduction.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a semiconductor device that is excellent in both thermal shock resistance reliability and moisture resistance reliability.

[Conventional technology]

2. Description of the Related Art Semiconductor elements such as transistors, ICs, and LSIs are sealed in plastic packages or the like to form semiconductor devices from the viewpoint of protecting the external environment and enabling handling of the elements. A typical example of this type of package is a dual in-line package (DIP). This DIP is of a pin insertion type, and a semiconductor device is attached by inserting pins into a mounting board.

Recently, the integration and speed of semiconductor devices such as LSI chips have been increasing, and in addition, the demand for smaller and more highly functional electronic devices has led to higher density packaging. From this point of view, surface mount packages have become mainstream instead of pin insertion type packages such as DIP. In a semiconductor device using this type of package, pins are taken out in a plane and fixed directly to the surface of the mounting board by soldering or the like. These surface-mounted semiconductor devices have pins that can be taken out on a flat surface, and have the advantages of being thin, light, and small.
Therefore, it has the advantage that it occupies only a small area on the mounting board, and also has the advantage that it can be mounted on both sides of the board.

[Problem to be solved by the invention]

However, in a semiconductor device using a surface mount package as described above, if the package itself absorbs moisture before surface mounting, there is a problem that cracks occur in the package due to the vapor pressure of moisture during solder mounting. That is, in a surface-mounted semiconductor device as shown in FIG. It accumulates on the back side of the. Then, when performing solder surface mounting such as paper phase soldering,
The accumulated moisture is vaporized by the heating during the solder mounting, and its vapor pressure pushes the resin part on the back side of the Guibond pad 4 downward, creating a gap 5 there. At the same time, a crack 6 is generated in the package 3. In FIGS. 1 and 2, 8 is a bonding wire.

As a solution to such problems, there are methods in which the semiconductor element is sealed in a package, the resulting semiconductor device is then packaged in a moisture-proof package, and the semiconductor device is opened and used immediately before surface mounting. A method of drying at 100°C for 24 hours and then performing solder mounting has been proposed and has already been implemented. However, such a pretreatment method has the problem that the manufacturing process is long and labor-intensive.

On the other hand, in order to improve the low hygroscopicity of the encapsulating resin, an epoxy resin composition for semiconductor encapsulation is prepared using, for example, an epoxy resin having a skeleton represented by the following general formula (IV), and an epoxy resin having a skeleton represented by the following general formula (IV). It has been proposed that an epoxy resin m-acid containing a novolak resin represented by V) is used.

However, when a semiconductor element is encapsulated using the above-mentioned epoxy resin composition, although the moisture absorption rate of the encapsulation resin is reduced, the moisture resistance reliability after solder mounting is reduced.

The present invention was made in view of the above circumstances, and its purpose is to provide a semiconductor device that does not require pretreatment when mounted on electronic equipment and has excellent low stress properties that can withstand heating during solder mounting. shall be.

[Means to solve the problem]

In order to achieve the above object, the semiconductor device of the present invention includes:
The structure is such that a semiconductor element is sealed using an epoxy resin composition containing the following components (A) and (B).

(A) An epoxy resin represented by the following general formula (I).

(B) A reaction product obtained by preliminarily reacting a silane compound represented by the following general formula (II) and a phenol aralkyl resin represented by the following general formula (I[[).

(XteH+l S!廿Y), -, ... (II) [Function] As a method to prevent the occurrence of package cracks, ■
Three methods can be considered: suppressing moisture absorption into the sealing resin, ■ increasing the adhesive strength between the back side of the Guibond pad and the surface of the semiconductor element, and the sealing resin, and ■ increasing the strength of the sealing resin itself. . This invention is based on the method (2) above to significantly reduce the water absorption rate of the sealing resin to suppress moisture absorption into the sealing resin, and also based on the method (2) above, the surface of the semiconductor element and the sealing resin are bonded together. By increasing the adhesive force between the two, it is intended to improve the moisture resistance of the package itself and the adhesive strength of the sealing resin. Therefore, a reaction product of a special epoxy resin represented by the above general formula (1), a silane compound of the above general formula (If), and a phenol aralkyl resin of the above general formula (■) is used. As a result, it is possible to significantly improve the package crack resistance and moisture resistance reliability of the sealing resin at high temperatures (215 to 260° C.) such as in solder mounting.

The epoxy resin composition used in this invention has the general formula (
A special epoxy resin (component A) represented by I), a silane compound represented by the general formula (II), and a silane compound represented by the general formula (I[
The pre-reaction product of I) with the phenolic aralkyl resin (
It is obtained using component B) and is usually in the form of a powder or a tablet formed by compressing it.

The above-mentioned special epoxy resin of component A is a biphenyl type epoxy resin and is represented by the following general formula (1).

0 In this way, by adding a lower alkyl group to a phenyl ring having a glycidyl group, it becomes water repellent. The epoxy resin component may be composed only of the above-mentioned special epoxy resin, or may be used in combination with other commonly used epoxy resins. In the former case, all of the A component is composed of the special epoxy resin of the above general formula (1), and in the latter case, a part of the A component is composed of the special epoxy resin of the above general formula (I). It will be done. Examples of the above-mentioned commonly used epoxy resins include various epoxy resins such as Talesol novolac type, phenol novolac type, novolac bis A type, and bisphenol A type. The above-mentioned novolac type epoxy resin usually has an epoxy equivalent of 150 to 250. Softening point 50
-130°C is used, and the cresol novolac type epoxy resin has an epoxy equivalent of 180 to 210.
Generally, those having a softening point of 60 to 110°C are used. When using both in combination in this way, it is preferable to set the epoxy resin represented by the above general formula (1) at 20% (hereinafter abbreviated as "%") or more of the entire epoxy resin component, especially Preferably it is 50% or more.

The special reaction product which is the above B component is expressed by the following general formula (
It is obtained by preliminarily reacting a specific silane compound represented by II) with a specific phenol aralkyl resin represented by the following general formula (I).

(X+; TV'Si dimension Y) 3-4...(II) That is, the above-mentioned special reaction product is the organic group X and the alkoxy group Y of the specific silane compound represented by the above general formula (n). is obtained by reacting with the ○H group in a specific phenol aralkyl resin represented by the general formula (III) and dealcoholizing it.

As the specific silane compound represented by the above general formula (n), a silane coupling agent can be used, and specifically, N-(2-aminoethyl)-3-aminopropylmethyldimethoxysilane, N -(2-aminoethyl)-
3-aminopropyltrimethoxysilane, 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, N,N-bis[(methyldimethoxysilyl)propyl]amine, N,N-bis[3-(methyldimethoxy) silyl)propyl]ethylenediamine, N, N
-bis(3-()rimethoxysilyl)propyl]amine, N,N-bis(3-(1-rimethoxysilyl)propyl)ethylenecyan, 3-(N,N-diglycidyl)
Aminopropyltrimethoxysilane, N-glycidyl-
N,N-bis[3-(methyldimethoxysilyl)propyl]amine, N-glycidyl-N,N-bis[3-(trimethoxysilyl)propyl]amine, 3-glycidoxypropylmethyldimethoxysilane, 3-glycidoxyprobyltrimethoxysilane, 3-mercaptotrimethoxysilane,
3-Mercaptopropyltrimethoxysilane, N-((
3-)rimethoxysilyl)propyl] diethylenetriamine, N-((3-trimethoxysilyl)propyl)
Examples include triethylenetetraamine, N-3-)dimethoxysilylpropyl-m-phenylenediamine, and the like.

The specific phenolic aralkyl resin represented by the above general formula (III) acts as a curing agent for the above-mentioned special epoxy resin, and is obtained by reacting an aralkyl ether and phenol with a Friedel Krach catalyst. . Generally, condensation polymer compounds of α, α' dimethoxy p-xylene and phenol monomers are known.

Here, when the above-mentioned phenol aralkyl resin uses phenol monomer as one of the polycondensation monomers, the above-mentioned phenol monomer may remain as a reaction residue in the final polymerized compound, and usually, the phenol is removed under reduced pressure in the final reaction step. It is produced by distilling off the phenol monomer through a process until a predetermined softening point is reached. However, even after the above steps, phenol monomers may remain. The present inventors discovered that when a semiconductor element is molded by transfer molding using an epoxy resin composition containing a phenol aralkyl resin in which a large amount of phenol monomer remains, in some cases, the sealing resin (
It was encountered that the cured product of the epoxy resin composition was difficult to release from the mold. Based on this experience, the present inventors came up with the idea that the remaining amount of phenol monomer might affect the mold releasability of the mold, and conducted repeated research on this issue. As a result, it was found that there is a correlation between the amount of free phenol (free phenol monomer) remaining in the phenol aralkyl resin and the mold releasability of the mold. As a result of further research, we found that the amount of free phenol remaining in the phenol ara5 alkyl resin was reduced to 0.5%.
It has been found that mold releasability becomes good when the setting is as follows. Particularly preferred is 0.2% or less.

As the specific phenol aralkyl resin represented by the above general formula (DI), it is preferable to use one having a softening point of 70 to 110'' and a C1 hydroxyl equivalent of 150 to 220.

Further, the above-mentioned phenol aralkyl resin may constitute a curing agent component by itself, or may be used in combination with other commonly used phenol resins. In the former case, the entire curing agent component is composed of the above-mentioned phenol aralkyl resin, and in the latter case, a part of the curing agent component is composed of the above-mentioned phenol aralkyl resin. Examples of the above-mentioned commonly used phenolic resins include phenol novolak, cresol novolak, and the like. These novolac resins have a softening point of 50 to 11
It is desirable to use one having a 0°C hydroxyl equivalent of 70 to 150. When the above-mentioned phenol aralkyl resin and such a normal phenol resin are used together, it is preferable that the above-mentioned phenol aralkyl resin accounts for 50% or more of the entire curing agent component, particularly preferably 70%.
That's all. And the above phenol aralkyl resin (
The blending ratio of the phenolic aralkyl resin is 0.7 to 1 hydroxyl group in the phenol aralkyl resin per equivalent of epoxy group in the special epoxy resin (component A).
．． It is suitable to mix so that it becomes 3 equivalents. More preferred is 0.9 to 1.1 equivalents.

The reaction product (component B) consisting of the specific phenol aralkyl resin represented by the above general formula (III) and the specific silane compound represented by the above general formula (II) can be obtained, for example, as follows. It will be done. That is, the above-mentioned specific silane compound and specific phenol aralkyl resin are appropriately blended in a reaction vessel equipped with a stirring device, and heated at 120 to 180°C.
Particularly preferably, the temperature is raised to 130 to 150°C, and the two are reacted to produce a reaction product. Next, the alcohol produced in this reaction is removed from the yarn by degassing or the like under conditions of 130 to 180°C.

7 In addition to the special epoxy resin as component A and the reaction product as component B, the epoxy resin composition used in this invention may optionally contain inorganic fillers, curing accelerators, flame retardants, wax, etc. is used.

Examples of the inorganic filler include crystalline and meltable fillers, as well as aluminum oxide, beryllium oxide, silicon carbide, silicon nitride, and the like.

The above-mentioned curing accelerators include amine type and phosphorus type.

Curing accelerators such as boron type and phosphorus-boron type are mentioned,
Used alone or in combination.

As the flame retardant, compounds such as novolac type brominated epoxy, bis A type epoxy, antimony trioxide, and antimony pentoxide may be used alone or in combination as appropriate.

The above-mentioned coupling agents include glycidyl ether type, amine type, and thiocyan type.

Methoxy or ethoxysilane such as urea type,
They may be used alone or in combination as appropriate.

8 Methods of using it include triblending or preheating the filler, or premixing the organic component raw material, but there are no particular limitations. do not have.

Examples of the wax include compounds such as higher fatty acids, higher fatty acid esters, and higher fatty acid calcium, which may be used alone or in combination.

The epoxy resin composition used in this invention includes:
In addition to the above additives, rubber components such as silicone oil, silicone rubber, and synthetic rubber are blended to reduce stress, and ion trapping agents such as hydrotalcite are added to improve reliability in moisture resistance tests. May be blended.

The epoxy resin composition used in this invention can be produced, for example, as follows.

That is, first, a reaction product (component B) is produced by preliminarily reacting the specific silane compound and the specific phenol aralkyl resin under the above conditions. next,
This reaction product and the above-mentioned special epoxy resin of Precept 9 are blended and premixed in appropriate proportions, and then kneaded in a heating state using a mixer such as a real kissing roll machine to melt and mix. The product can then be produced through a series of steps of cooling it to room temperature, pulverizing it by known means, and, if necessary, compressing it into tablets.

The encapsulation of a semiconductor element using such an epoxy resin composition is not particularly limited, and can be performed by a known molding method such as ordinary transfer molding.

The semiconductor device thus obtained consists of a special epoxy resin (component) represented by the general formula (1) contained in the epoxy resin composition, the general formula (II) and the general formula CI[ Due to the action of the preliminary reaction product (component B) with It has excellent durability and moisture resistance, and does not cause package cracks even when soldered. Moreover, by adjusting the amount of free phenol to 0.5% or less, it becomes possible to easily and reliably release the mold from the mold during transfer molding.

〔Effect of the invention〕

As described above, the semiconductor device of the present invention is constructed by resin-sealing a semiconductor element using an epoxy resin composition containing the above-mentioned special epoxy resin and special preliminary reaction product. Therefore, it has excellent adhesive strength between the semiconductor element and the sealing resin, does not cause package cracks even under severe conditions such as solder mounting, and has excellent moisture resistance and reliability.

Next, examples will be described together with comparative examples.

First, prior to Examples, compounds shown in Table 1 below were prepared.

(Leaving space below) ■ 22 Next, the phenolic resins C, D and silane compounds E, F, and G in Table 1 above were mixed in the proportions shown in Table 2 below, and the mixture was poured into a reaction vessel equipped with a stirring device. A preliminary reaction was carried out under the reaction conditions shown in the same table, and a reaction product J~0 was prepared by degassing (170°C). Note that the amount of free phenol contained in the phenol resin C (phenol aralkyl resin) was 0.5% or less.

(Left below) 3 4 [Examples 1 to 7, Comparative Examples 1 to 4] The above reaction products J to ○, epoxy resins A and B, and other additives were blended in the proportions shown in Table 3 below. The mixture was kneaded using a mixing roll machine at 100°C for 10 minutes to obtain a sheet-like composition.

Then, the obtained sheet-like composition was pulverized to obtain the desired powdered epoxy resin composition.

(The following is a blank space) 5 [Examples 8 and 9] Instead of the phenol resin C (phenol aralkyl resin) shown in Table 1 above, phenol aralkyl resins having different amounts of free phenol shown in Table 4 below were used. . An epoxy resin assembly was obtained in the same manner as in Example 1 except for the above.

Next, a semiconductor device was obtained by molding a semiconductor element by transfer molding using the powdered epoxy resin assembly obtained in Examples 1 to 9 and Comparative Examples 1 to 4. This semiconductor device is an 80-pin four-way flat package (QFP) (20 mm x 14 mm x 2.5 m thick).
m), with a chip size of 7 + n + n x 7 mm, a chip size of 6,5 mm x 6,5 + nm. The semiconductor device obtained in this way was immersed in solder at 260"C at 85°C/85% until package cranking occurred.
The critical moisture absorption time under RH was measured. In addition, a disk-shaped cured product with a thickness of 3 mm and a diameter of 50 mm was prepared using the above epoxy resin assembly (curing conditions: 180°C for 5 hours).
This disc-shaped cured product was heated at 85°C x 85% RH.
The sample was allowed to absorb moisture for 500 hours and the saturated moisture absorption rate was measured. Furthermore, the bending strength of the cured product was determined according to JIS-69115,17.
The measurement was carried out at 260°C according to the above. Then, the adhesive strength between the semiconductor element and the cured product was measured. These results are shown in Table 5 below. In addition, the said adhesive force was measured as follows. That is, as shown in FIGS. 3(A) and (B), the upper surface has a diameter a = 11 mm and the lower surface has a diameter b =
A truncated cone-shaped cured product 10 with a diameter h of 9 mm and a height h=10 mm was prepared, and 2 + n
A semiconductor element 11 measuring m x 2 mm x 0.4 mm in thickness was mounted. Then, the shear adhesive force between this truncated conical cured product 10 and the semiconductor element 11 was measured. In addition, the release load of the cured product of the obtained epoxy resin assembly from the mold was measured, and this was evaluated as the release property. The results are also shown in Table 5.

In addition, the said mold release load was measured as follows. That is, first, the upper stage 12 and the middle stage 1 as shown in FIG.
A mold 15 consisting of three stages, 3 and a lower stage 14, was prepared, and the mold surface of the mold 15 was cleaned with a cleaning resin. Thereafter, the epoxy resin assembly is filled into the mold 15 via the filling path (runner) 16 and transfer molded to form a molded rod 17 (top diameter C=18 mm, bottom surface diameter C=18 mm) as shown in FIG. diameter d=20 mm).

Next, as shown in FIG. 5(B), take out the middle stage 13, turn it over, place it on the support frame 19 as shown in FIG. 5(C), and use the bushing gauge 18 to
To release the molding rod 17 from the middle stage 13 by pushing the molding rod 17 in the direction shown in FIG. 5(D)>. Middle row 13 at this time
The load when releasing the molded rod 17 from the mold was measured. In the figure, 19 is a support frame.

(The following is a blank space) 9 30 From the results in Table 5, the three products of Comparative Example have a low saturated moisture absorption rate and a long limit moisture absorption time, but have a low adhesive strength to the semiconductor element. In addition, comparative height measurement products other than Comparative Example 3 have a certain degree of adhesive strength, but have a high saturated water absorption rate and a short critical moisture absorption time. On the other hand, actual height measurement has high adhesive strength, low saturated water absorption rate, and long limit moisture absorption time. Therefore, it can be seen that the actual height measurement has excellent moisture resistance reliability and low stress properties at high temperatures. Furthermore, it can be seen that the actual height measurement had a low mold release load and excellent mold releasability.

[Brief explanation of the drawing]

FIGS. 1 and 2 are longitudinal cross-sectional views illustrating the occurrence of package cracks in conventional semiconductor devices, and FIG. Plan view explaining the adhesive force measurement method, 3rd
Figure (B) is its front view, Figure 4 is a perspective view of the cured epoxy resin composition, Figures 5 (A), (B), (C) and (
D) is a process diagram illustrating a method of measuring mold release load. 1 7 Now Figure (A) Figure Figure 5 Figure (A) Figure Figure (B) Figure (C) Figure (D)

Claims (5)

[Claims] (1) A semiconductor device in which a semiconductor element is sealed using an epoxy resin composition containing the following components (A) and (B). (A) An epoxy resin represented by the following general formula (I). ▲There are mathematical formulas, chemical formulas, tables, etc.▼…(I) [In the above formula (I), R_1 to R_4 have 1 carbon number
~4 alkyl group. ] (B) a silane compound represented by the following general formula (II);
A reaction product obtained by preliminary reaction with a phenol aralkyl resin represented by the following general formula (III). ▲There are mathematical formulas, chemical formulas, tables, etc.▼...(II) [In the above formula (II), It is an organic group, and Y is an alkoxy group having 1 to 4 carbon atoms. n is 0, 1 or 2. ] ▲There are mathematical formulas, chemical formulas, tables, etc.▼...(III) [In the above formula (III), m is 0 or a positive integer. ] (2) The silane compound represented by general formula (II) is at least one selected from the group consisting of 3-glycidoxypropyltrimethoxysilane, 3-aminopropyltrimethoxysilane, and 3-mercaptotrimethoxysilane. The semiconductor device according to claim 1, which is a silane compound. (3) The semiconductor device according to claim (1) or (2), wherein the amount of free phenol contained in the phenol aralkyl resin represented by general formula (III) is 0.5% by weight or less. (4) An epoxy resin composition for semiconductor encapsulation containing the following components (A) and (B). (A) An epoxy resin represented by the following general formula (I). ▲There are mathematical formulas, chemical formulas, tables, etc.▼…(I) [In the above formula (I), R_1 to R_4 have 1 carbon number
~4 alkyl group. ] (B) a silane compound represented by the following general formula (II);
A reaction product obtained by preliminary reaction with a phenol aralkyl resin represented by the following general formula (III). ▲There are mathematical formulas, chemical formulas, tables, etc.▼...(II) [In the above formula (II), It is an organic group, and Y is an alkoxy group having 1 to 4 carbon atoms. n is 0.1 or 2. ] ▲There are mathematical formulas, chemical formulas, tables, etc.▼...(III) [In the above formula (III), m is 0 or a positive integer. ] (5) The epoxy resin composition for semiconductor encapsulation according to claim (4), wherein the amount of free phenol contained in the phenol aralkyl resin represented by general formula (III) is 0.5% by weight or less.