JPS59195851A - Manufacture of semiconductor device - Google Patents

Abstract

PURPOSE:To obtain the semiconductor device having a high humidity resistance by a method wherein a polymer comprising a repeating structural unit expressed by the specified general formulas is spread and is printed to form a protective coating on a surface of the semiconductor element which is sealed by use of a resin composition or ceramic after that. CONSTITUTION:The solution of a polymer comprising a repeating structural unit expressed by the general formulas ( I )-(III) (wherein R<1> and R<2> express the same or the different hydrocarbon radicals of one valency) is spread on surfaces of a semiconductor element 2, a lead wire 1 and so on. Next, a printing treatment is performed by heating with 100 deg.C or over, more preferably with 150- 300 deg.C. By this treatment, the polymer increases the molecular weight and crosslinking occurs to form a protective coating layer. The coating layer should be formed preferably so as to have a thickness of 10mum or less, more particularly of 1mum or less for obtaining good effects. This is attained by adjusting the concentration of the solution properly under 5wt% usually. Subsequently, the object composed of the element 2 and the lead wire 1 comprising a protective coating layer 3 is sealed, e.g. with an epoxy resin composition 6, thereby offering the semiconductor device.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for manufacturing a semiconductor device that maintains excellent operational stability even when left in high temperature and high humidity conditions for a long time.

Moisture resistance is an essential characteristic of semiconductor devices, and as devices become more dense and reliable, requirements for moisture resistance are becoming increasingly strict.

In particular, resin-sealed semiconductor devices are more susceptible to high-temperature and high-humidity conditions (for example, 65 to 85C) than ceramic-sealed semiconductor devices.
In addition, the operation reliability was poor at a relative humidity of 95% or at 121 U (2 atmospheres of supersaturated steam).

As an improvement measure, a method has been proposed in which the adhesiveness between the surface of the semiconductor element and the sealing resin is increased to suppress the intrusion of moisture into the sealing device.

However, these conventional measures have not been able to adequately cope with the increasing density and reliability of semiconductor devices, and it has been felt that there is a need to develop a more effective method.

The present invention is the result of repeated studies for this purpose, and an object of the present invention is to provide a semiconductor device, particularly a resin-sealed semiconductor device, with excellent moisture resistance.

The feature is that in a method of manufacturing a semiconductor device in which a protective coating is applied to at least the surface of a semiconductor element and then sealed using a resin composition, ceramics, etc., the protective coating is formed using the general formula (1 (1) and R2 represent the same or different monovalent hydrocarbon groups) is coated and baked.

In the present invention, the polymer used as the protective coating includes, for example, a polymer obtained by a polycondensation reaction between tris(trimethoxysilyloxy)aluminum and tris(trimethylsilyl)phosphate (wherein Me represents a methyl group). ,n (Mess 1o)3At+n (M
e3SiO)3PO->MesSjO4AL-0-P
-O')-8jMes11 1 'O8IMe3 08iMe:s' n or a polymer obtained by a polycondensation reaction of tris(triethylsilyloxy)aluminum and triethylsilyloxyphosphinic acid (in the formula, Et represents an ethyl group), (n+t)(Et3SiO)aAt+n Ets S
iOP(OXOH)2 or alternatively, the reaction of tris(proxy)aluminum with methylbutoxyphosphine acid chloride (wherein Bu represents a butyl group), the sequential reaction of dibutoxy(methylbutoxyphosphinoxy)aluminum synthesized according to A polycondensate of diisogloboxy(methylcresyloxyphosphinoxy)aluminum synthesized by hydrolysis, polyhydrolysis, or in the same manner as above;
(In the formula, Pr represents an i-globyl group) Men(PrO)2At OP OC6H4Me-'1 and the like.

These polymers are prepared by polycondensing the respective reaction component mixtures at approximately 120-230C.
Obtained in a state soluble in organic solvents. The polymer is preferably applied as a solution to the surface of a semiconductor device, etc.
Examples of the solvent include aromatic hydrocarbons such as benzene and toluene, alcohols such as ethanol and 2-glopanol, and polar solvents such as keto/s, chlorinated hydrocarbons, and N-methyl birolide.

Solutions of these polymers are applied to the surfaces of semiconductor elements, lead wires, and the like. (FIGS. 1-3) As a coating method, there are methods such as dipping the element and lead wires in the solution, dropping the solution onto the element and lead wires, spraying, and spinner coating.

The semiconductor elements and lead wires coated with the polymer solution by the method described above are then coated with at least 1000 or more
Particularly preferably, heat baking is performed at 150 to 300 tT. This treatment increases the molecular weight of the polymer and allows it to be brushed to form a protective coating layer. The coating layer should have a thickness of 10 μm or less, especially 1 μm in order to exhibit a good effect.
It is preferable to form the following by adjusting the concentration of the solution appropriately, usually below 5% by weight.
achieved.

Next, as shown in FIG. 1, the semiconductor device of the present invention is obtained by sealing the element 2 having the protective coating layer 3 and the lead wires with, for example, the following epoxy resin composition 6.

Epoxy resin for sealing Acid novolac type epoxy resin 100 parts by weight Phenol-formadehyde resin 55 parts by weight Imidazole catalyst 3 parts by weight Fused silica glass powder
480 parts by weight Evosha disilane
2 parts by weight to 2 parts by weight to 2 parts by weight to 1 part by weight to carbon black.
After kneading for a minute, the mixture was roughly pulverized to prepare a sealing resin composition.

In the present invention, as a method for sealing the coated semiconductor element, in addition to resin sealing, sealing using can, solder-fused ceramic, glass-fused ceramic, etc. can be adopted.

Among the above-mentioned sealing methods, examples of sealing resin compositions that are particularly effective in the present invention for resin-encapsulated semiconductor devices include thermosetting resins such as epoxy resins, phenol resins, and melamine resins. There are compositions using resins, urea resins, diallyl phthalate resins, unsaturated polyester resins, urethane resins, addition type polyimide resins, silicone resins, polyvarabinylphenol resins, etc., and thermoplastic resins such as polyethylene, polystyrene, polyptadiene resins, etc. /, perfluoroethylene, polyamide, polyether, polyester, polyamide ether, polyamide ester, polyimide ether, polyamide ether, etc.

Among the above, epoxy resin compositions are particularly preferred.

Examples of the epoxy resin include diglycidyl ether of bisphenol A, butadiene dieboxide, 3,4
-Epoxycyclohexylmethyl-(3,4-epoxy)cyclohexanecarboxylate, vinylcyclohexane dioxide, 4.4'-di(1,2-epoxyethyl)diphenyl ether, 4. ．． 4'-(1,2-epoxyethyl)biphenyl, 2,2-bis(3,4-epoxycyclohexyl)propane, glycidyl ether of lesotvsin, diglycidyl ether of phloroglucin, dimethyl phloroglucin/ glycidyl ether,
Bis-(2,3'-epoxycyclobentyl)ether, 2-(3,4-epoxy)cyclohexa7-5.5-
Spiro(3,4-epoxy)-cyclohexa7-m-
Dioxa/, bis-(3,4-epoxy-6-methylcyclohexyl)adipate, N,N'-m-phenylenebis(4,5-epoxy-1,2-cyclohexyl)
Functional epoxy compounds such as dicarboximide, triglycidyl ether of paraaminofuranol, polyallyl glycidyl ether, 1,3.5-tri(1,2-epoxyethyl)benzene, 2121'4,4'-tetraglycidyl quine Tri- or higher functional epoxy compounds such as benzophenone, polyglycidyl ether of phenolformaldehyde novolac, triglycidyl ether of glycerin, and triglycidyl ether of methylolpropane are used. One or more of the above compounds can be used in combination depending on the use and purpose. A curing agent is used in combination with these epoxy resins. They are written by Hiroshi Kakiuchi; Epoxy Resin (published September 1970) 109-149
Page, Lee, Nevi le; Epoxy
l(, e3in3 (MCQr3W −Ht + +
Book c any Inc, New York,
(published in 1957) pages 63-141, p, E, B
by Epoxy R, esins Tec
hnology(Interscience pubf
ishers, New York.

(published in 1968), pages 45 to 111, such as aliphatic polyamines, aromatic polyaminos, amines including secondary and tertiary amines, carboxylic acids, carboxylic acid anhydrides, aliphatic polyamines, etc. and aromatic polyamide oligomers and polymers, boron trifluoride-amine complexes, phenolic resins, melamine resins,
Synthetic resin initial condensates such as urea resin and urethane resin, others, dianediamide, carboxylic acid hydrazide,
Examples include polyaminomaleimides.

The above-mentioned curing agent can be used in one or more forms depending on the use and purpose.

In particular, phenol borac resin is highly effective in terms of adhesion of the cured resin to metal inserts and workability during molding.
It is suitable as a curing agent component of the above-mentioned semiconductor encapsulation material.

In the resin composition, a known catalyst known to be effective in accelerating the curing reaction between the epoxy compound and the heptaboric phenol resin can be used.

Such catalysts include, for example, triethanolamine,
Tertiary amines such as tetramethylbutanediamine, tetramethylbutanediamine, tetramethylhex/diamine, triethylenediamine, dimethylaniline, oxyalkylamines such as dimethylaminoethanol, dimethylaminopetanol, and tris(dimethylaminemethyl)
There are amines such as phenol, N-methylmorpholine, and N-ethylmorpholine.

Also, cetyltrimethylammonium bromide, cetyltrimethylammonium chloride, dodecyltrimethylammonium iodide, trimethyldodecylammonium chloride, benzyldimethyltetradecylammonium chlorite, he/cylmethylpalmitylammonium chloride, allyldodecyltrimethylammonium bromide, benzyldimethylstearylammonium Examples include quaternary ammonium salts such as bromide, stearyltrimethylammonium chloride, and be/zyldimethyltetradecylammonium acetate.

Also, 2-ethylimidazole, 2-cundecylimidazole, 2-heptadecyl imidazole, 2-methyl-
4-ethylimidazole, 1-butylimidazole, 1
-Propyl-2-methylimidazole, 1-benzyl-
2-methylimidazole, 1-cyanoethyl-2-methylimidazole, 1-cyanoethyl-2-undecylimidazole, 1-77noethyl-2-phenylimidazole, 1-azi/-2-methylimidazole, 1-azine-2- Imidazoles such as undecyl imidazole, triphenylphosphine tetraphenylborate, tetraphenylphosphonium tetraphenylborate, triethylamine tetraphenylborate, N-methylmorpholine tetraphenylborate, 2-ethyl-4-methylimidazole tetraphenylborate, 2-ethyl -1,4-dimethylimidazole tetraphenylborate natonotetraphenylboron salt and the like.

In the present invention, depending on the purpose and use of the resin composition,
Various inorganic substances and additives can be mixed and used. Specific examples include zircon, silica, fused silica glass, alumina, aluminum hydroxide, glass, quartz glass, calcium silicate, gypsum, calcium carbonate, magnesite, clay, kaolin, talc, iron powder, copper powder. , mica, asbestos, silicon carbide, boron nitride, molybdenum disulfide, lead compounds, lead oxides, zinc white, titanium white, carbon black, and other fillers.

are higher fatty acids, release agents such as waxes, epoxysila/, vinylsila/, aminosila/, poran compounds,
These include coupling agents such as alkoxy titanate compounds and aluminum chelate compounds. Additionally, known flame retardants including antimony, membrane compounds, bromine and chlorine can be used.

Example 1 An equimolar mixture of tris(triethylsilyloxy)aluminum triethylsilyloxyphosphinic acid and o
At 00C, a polymer represented by the formula 0 (average molecular weight about 5600) obtained by polycondensation while distilling by-products was 2-
Dissolved in a mixed solvent of equal amounts of globanol and toluene to 0.
A 5% by weight solution was prepared.

The device structure when the resin solution is used as a multilayer (two-layer) wiring insulating film is shown in FIGS. 2 and 3.

The device consists of a Si device substrate, a SiOx insulating layer, a polysilicon layer, and a first layer of aluminum wiring (4-
After forming I), the above resin solution was applied (for spinner stems) and baked (270C).

After 60 minutes) (layer 3-1), a positive resist was applied and patterning of through holes was performed. Plasma etching was performed using the mulberry and CF402 as a reaction gas.

The positive resist was then removed using a plasma asher using 02 as a reactive gas.

Next, after forming the second eyelet aluminum wiring (4-II), the above resin solution was further applied and baked (under the same conditions as above). (3-n layer) FIG. 3 shows a case (5 layers) in which a polyimide resin (Hitachi Chemical Co., Ltd.: PIQ) is used as the coating resin for the second layer.

A memory LSI product in which the semiconductor device of the present invention is packaged in a gas-fused ceramic package (64 bits D-B, AM
Even after 5,000 hours of storage test (PCT) in supersaturated steam at 121C and 2 atm, there was no disconnection failure due to corrosion of the At wiring, and an LSI with excellent multiplicity was obtained.

Example 2 Triing globoxyaluminum and phenoxymethylphosphine/acid chloride were taken in substantially equimolar proportions, and 13
A solid polymer obtained by polycondensation while raising the temperature from around 0C to 200 tlt was prepared into a 1 weight solution using a 2-globanol-xylene mixed solvent. The solution was applied to a semiconductor element in the same manner as in Example 1, and after the solvent was evaporated, it was heated to 230C and baked, resulting in the formation of a coating layer that adhered to the element.

Example 3 Water-containing butanol was added to a xylene solution of methyl, poxyphosphinoxyaluminum diptoxide so that it became warm compared to the aluminum compound.
, 120 to 130C to obtain a solid polymer represented by the formula.

This polymer was dissolved in toluene to prepare a 1% by weight resin solution. FIG. 1 shows an element structure when the solution is used as a multilayer (two-layer) wiring insulating film.

It is shown in Figure 2.

The device consists of a Si device substrate, a 5I02 insulating layer, a polysilicon layer, and a first layer of aluminum wiring (2-
After forming I), the above resin coating material was applied (for tinted/nerar cabinets) and baked (250C for 160 minutes) (5
-I) After that, a positive resist was applied and patterned with multi-holes. Next, in step A, plasma etching was performed using CF4-O2 as a reactive gas. Then 0. The positive resist was removed by a plasma asher using as a reactive gas.

Next, the second layer of aluminum! After forming (2-n), the above resin liquid was further applied and baked (under the same conditions as above). (3-n layer) In addition, in Figure 2, polyimide resin (Hitachi Chemical PIQ) is used as the coating resin for the second layer.
) is used (4 layers).

A memory LSI product in which the semiconductor device of the present invention is resin packaged using an epoxy resin molding material using phenol novolac resin as a hardening agent (16 bits D-RAM)
Even after 2,000 hours of bias application at 85C and 85C relative humidity, there was no disconnection failure due to corrosion of the At wiring, and an LSI with excellent humidity resistance and reliability was obtained.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional view of a semiconductor device according to an embodiment of the present invention, and FIGS. 2 and 3 are partial cross-sectional views of an element portion of the semiconductor device according to the present invention.

Claims (1)

[Claims] 1. In a method for manufacturing a semiconductor device, in which a protective coating is applied to at least the surface of a semiconductor element and then sealed using a resin composition, ceramics, etc., the protective coating is formed by the general formula (in the formula , R1 and R2 represent the same or different one-stroke hydrocarbon groups) A method for manufacturing a semiconductor device, comprising applying and baking a polymer having a repeating structural unit.