JPH0611039B2 - Semiconductor device - Google Patents

Description

TECHNICAL FIELD OF THE INVENTION The present invention relates to a semiconductor device in which the surface of a semiconductor element is coated with a thermosetting polyimide-epoxy modified resin composition.

[Technical Background of the Invention and its Problems] The exposed surface of a pn junction formed on a semiconductor element is sensitive to the atmosphere and is therefore stabilized (passivated) by coating with various stabilizing materials. . Conventionally, a silicon dioxide film or a silicon nitride film is formed as a junction stabilizing film between an emitter, a base, and a collector on the surface of an element on a semiconductor substrate, and further a base electrode is formed on the stabilizing film.
The emitter electrode is formed of an aluminum vapor deposition film.

In the conventional semiconductor device, the substrate pellet is fixed to the tip of the tab lead, the electrode of the element and the lead wire are bonded by a wire of gold or aluminum, and the pellet surface is protected by an undercoat resin. The substrate pellets are embedded in the mold resin to provide high mechanical strength and to protect from the outside air.

However, when the above-mentioned semiconductor device is subjected to temperature change and exposed to a high-humidity atmosphere, the difference in thermal expansion coefficient between the mold resin and the bonding wire or the mold resin and the semiconductor substrate or the swelling of the undercoat resin due to moisture absorption causes Then, a void is generated at the interface between the mold resin and the bonding wire and at the interface between the mold resin and the semiconductor substrate. Water contained in the outside air penetrates through the voids and reaches the surface layer of the semiconductor substrate. Generally, the adhesiveness between non-metallic materials such as silicon and silicon dioxide and the resin is significantly reduced by the intervention of water.

Therefore, the moisture that reaches the surface layer of the semiconductor substrate through the voids deteriorates the adhesiveness between the semiconductor substrate or the silicon dioxide film and the undercoat resin, and reaches the base electrode.

As a result, there is a drawback that the reverse breakdown voltage between the base and collector occurs due to the invasion of water, and the function as a semiconductor device cannot be achieved.

[Object of the Invention] The present invention provides a semiconductor device treated with an undercoat resin which has excellent adhesion to a bonding wire, a silicon substrate, or a stabilizing film such as a silicon dioxide film and which has excellent moisture resistance. It is intended to be provided.

[Summary of the Invention] As a result of intensive studies to achieve the above object, the present invention has found that the object can be achieved by using a thermosetting polyimide-epoxy modified resin composition described below. .

That is, in the present invention, in a semiconductor device in which the periphery of a semiconductor element is sealed with a sealing resin, (a) a bismaleimide and a triazine resin monomer as main components are directly or through another insulating material. A thermosetting polyimide-epoxy modified resin composition coating film comprising a resin (b) and an epoxy resin (b), wherein the thermosetting polyimide-epoxy modified resin composition is preferable. The solvent is (c) diethylene glycol monoalkyl ether acetate or diethylene glycol dialkyl ether solvent. Next, each component will be described.

First, as the resin (a) containing bismaleimide and a triazine resin monomer as main components, a compound represented by the general formula Bismaleimide, a dicyanate represented by the general formula N≡C—O—Ar ₂ —O—C≡N, and a triazine ring in which 3 or more molecules of dicyanate are cyclopolymerized in the molecule. And a cyanate group (N≡C—O—) at the molecular end, for example, a triazine resin having the following structural formula (However, Ar ₁ and Ar ₂ represent the same or different divalent aromatic groups). An example of such a resin is BT resin (trade name) manufactured by Mitsubishi Gas Chemical Company.

Next, as the component (b) epoxy resin, for example, there are the following bisphenol diepoxides. Shell Chemical Co., Ltd. Epikote 827,828,8
34,1001,1002,1004,1007,10
09, DER330, 331, 33 made by Dow Chemical Co.
2,334,335,336,337,660,66
1,662,667,668,669, Ciba-Geigy Araldite GY250,260,2
80, 6071, 6084, 6097, 6099, Jon
es Dabney's Epi-Res 510, 5101, Dainippon Ink and Chemicals' Epicron 810, 1000, 10
10, 3010 (all above are trade names). Furthermore, by using, for example, a novolac epoxy resin having an average number of epoxy groups of 3 or more as the epoxy resin, it is possible to further improve the adhesive strength of the resin composition. As the novolac epoxy resin used, one having a molecular weight of 500 or more is suitable. Examples of such novolac epoxy resin are as follows. Ciba Geigy Araldite EPN1138, 1139, ECN127
3,1280,1299, EEN43 manufactured by Dow Chemical Company
1, DEN438, Epicoat 152 manufactured by Shell Chemical Co.,
154, Union Carbide ERR-0100, E
RRB-0447, ERLB-0448 etc. are mentioned.

The mixing ratio of the resin containing (b) the bismaleimide and the triazine resin monomer as main components to the epoxy resin (b) is preferably in the range of 10:90 to 90:10 (weight ratio). When the blending ratio of the resin containing (b) the bismaleimide and the triazine resin monomer as main components is less than the above range, the softening temperature of the coating film of the obtained resin composition becomes low and the adhesive strength at high temperature becomes poor. On the contrary, if the amount exceeds the above range, the flexibility of the obtained resin composition decreases, which is not preferable. Therefore, it is limited to the above range.

When the resin (a) containing the bismaleimide and the triazine resin monomer as main components and the epoxy resin (b) are blended, these resins may be simultaneously added to a common solvent and dissolved. However, it is desirable to first dissolve the latter in a solvent and then the former.

The (c) organic solvent, which is another component of the resin composition used in the present invention, is used as a general ink solvent, and does not immerse the emulsion of the screen, has no toxicity and has little odor, diethylene glycol monoalkyl. Examples thereof include ether acetate or diethylene glycol dialkyl ether type solvents. Specific examples include diethylene glycol monomethyl ether acetate, diethylene glycol monobutyl ether acetate, diethylene glycol dimethyl ether, and diethylene glycol dibutyl ether. These solvents may be used alone or in combination of two or more. In addition, after dissolving the resins (a) and (b) above in a solvent,
By heating and reacting for several hours in the temperature range of 80 to 120 ° C., the viscosity and molecular weight of the resin composition are adjusted by causing partial reaction between cyanate groups, cyanate groups and epoxy groups, and cyanate groups and bismaleimide. You can also do it. Further, a known curing catalyst may be added to this resin composition in addition to the above-mentioned necessary components. As a curing catalyst,
For example, usual polymerization initiators such as benzoyl peroxide, dicumyl peroxide, ditertiary butyl peroxide, and azobisisobutyronitrile, and tertiary amines, imidazoles, organometallic salts and chlorides as accelerators Used as appropriate. Further, if necessary, a filler made of silica powder, mica powder, inorganic powder such as carbon powder or polyimide powder, resin powder such as polytetrafluoroethylene powder is added to reduce the heat shrinkage of the cured resin. Alternatively, the thermal conductivity can be improved. Furthermore, in order to change the physical properties of the cured resin as needed, in addition to the resin containing bismaleimide (a) and a triazine resin monomer as main components and the epoxy resin (b), other resins such as polyester resin, It can also be modified by adding a small amount of a polyimide resin, a polyesterimide resin or the like. The mixing ratio of the resin component and the solvent (resin concentration) can be arbitrarily changed according to the coating method, and if necessary, increase the resin concentration to lower the viscosity by heating this during coating. You may use it.

The present invention is a semiconductor device in which the surface of a semiconductor element is coated with the thermosetting polyimide-epoxy modified resin composition obtained as described above.

This will be described below with reference to the drawings.

In FIGS. 1 and 2, reference numeral 1 denotes a semiconductor substrate made of silicon or the like, and a PNP transistor, for example, is formed on the surface layer thereof. On the surface of the semiconductor substrate 1, a silicon dioxide film 2 for insulation and protection between the emitter, the base and the collector is formed, and a base electrode 3 and an emitter electrode 4 (further, an aluminum metal film band 9 in FIG. 2) are formed. It is formed of an aluminum vapor deposition film. When packaging this planar type transistor, the semiconductor substrate 1 is fixed to the tip of the tab lead 7, and the electrode of the device and the lead wire are bonded by the wire 5 of gold or aluminum, and the thermosetting polyimide-epoxy modified resin composition is used. After covering and protecting with the undercoat resin 6 consisting of
The semiconductor substrate 1 including the tip portions of the tab leads 7 is molded with a resin 8 in order to provide mechanical strength and to protect it from the outside air.

[Effects of the Invention] As described above, since the thermosetting polyimide-epoxy modified resin composition is undercoated, it has excellent adhesive strength with semiconductor substrates, silicon dioxide films, etc. There is no deterioration due to, no leak current due to interfacial polarization of the undercoat resin, etc. occurs, and the connection between the wire and the electrode is reliable.

[Examples of the Invention] The present invention will be specifically described below with reference to Examples.

"Parts" means "parts by weight", and the present invention is not limited to these examples.

Example 1 80 parts of Epicoat 828 and BT2170 (resin content 100
% Mitsubishi Gas Chemical Co., Inc. (trade name) 100 parts and a dissolution reaction of 120 parts of diethylene glycol diethyl ether at 120 ° C. for 1 hour to obtain a viscous thermosetting polyimide-epoxy modified resin composition. This was applied on the surface of a semiconductor substrate and a planar type transistor, heated and cured at 200 ° C. for 2 hours to form an undercoat resin film, and the outside was resin-sealed with an epoxy resin to manufacture a semiconductor device.

Example 2 200 parts of ECN1280 (trade name of Ciba-Geigy)
Diethylene glycol monobutyl ether acetate 60
Example 1 except that 200 parts of BT2170 were added and mixed at 100 ° C. after dissolution in 0 parts of solvent at 80 ° C. to use a viscous and transparent thermosetting polyimide-epoxy modified resin composition.
A semiconductor device was manufactured in the same manner as in.

Example 3 100 parts of Epicoat 1007 was dissolved in 180 parts of diethylene glycol monobutyl ether acetate at 90 ° C., and then 20 parts of BT2170 was added and uniformly dissolved to obtain a viscous thermosetting polyimide-epoxy modified resin composition. Was obtained, and a semiconductor device was manufactured in the same manner as in Example 1 except that this was used.

Comparative Example 4,4'-diaminodiphenyl ether and pyromellitic dianhydride were reacted in N, N'-dimethylacetamide in an equivalent amount. A polyimide solution having a resin content of 17% was applied to the surface of a planar transistor and a semiconductor substrate. , 200 ℃
The resin was heat-cured for 2 hours to form an undercoat resin film, and the outside was resin-sealed with an epoxy resin to manufacture a semiconductor device. The pressure-immersion test (120 ° C
A forced deterioration test was conducted by leaving it in saturated steam at 2 atm), and the results are shown in Table 1.

[Brief description of drawings]

FIG. 1 is a sectional view showing the structure of a semiconductor device according to the present invention, and FIG. 2 is a sectional view showing the structure of another semiconductor device to which the present invention is applied. 1 ... Semiconductor substrate, 2 ... Silicon dioxide, 3 ... Base electrode,
4 ... Emitter electrode, 5 ... Bonding wire, 6 ... Undercoat resin, 7 ... Metal film band, 8 ... Tab lead, 9 ...
Mold resin.

Claims (4)

[Claims] 1. In a semiconductor device in which the periphery of a semiconductor element is sealed with a sealing resin, (a) a bismaleimide and a triazine resin monomer as main components are directly or through another insulating material on the surface of the semiconductor element. A semiconductor device provided with a film of a thermosetting polyimide-epoxy modified resin composition comprising a resin (1) and an epoxy resin (b). 2. A thermosetting polyimide-epoxy modified resin composition comprising (a) a resin mainly containing a bismaleimide and a triazine resin monomer and (b) an epoxy resin,
The semiconductor device according to claim 1, comprising (c) a diethylene glycol monoalkyl ether acetate or a diethylene glycol dialkyl ether solvent. 3. A compounding ratio of (a) a resin containing bismaleimide and a triazine resin monomer as main components and (b) an epoxy resin in a range of 10:90 to 90:10 (weight ratio). 2. A semiconductor device according to claim 1. 4. A resin containing (a) a bismaleimide and a triazine resin monomer as main components is represented by the general formula: Bismaleimide, a dicyanate represented by the general formula N≡C—O—Ar ₂ —O—C≡N, and a triazine ring in which 3 or more molecules of dicyanate are cyclopolymerized in the molecule. And a cyanate group (N≡C-O
4. A semiconductor device according to any one of claims 1 to 3, wherein a triazine resin having-) (wherein Ar ₁ and Ar ₂ represent the same or different divalent aromatic groups).