JPH04196346A - Thin resin-sealed semiconductor device - Google Patents

Abstract

PURPOSE:To make it possible to obtain a resin-sealed semiconductor device, whose package is thin in thickness, by a method wherein a material made by impregnating a thermosetting resin in an inorganic or organic fiber is used as a sealing resin. CONSTITUTION:A material made by impregnating inorganic or organic fibers with thermosetting resin is used as a sealing resin. The reason why a base material 4 made by impregnating the inorganic or organic fibers with the thermosetting resin is used is for improving a sealing workability and moreover, is that the wet spread of the resin at the time of heating and hardening of the resin and the thickness of a sealing layer are inhibited in a constant range and moreover, the mechanical strength of the hardened resin is increased and for other reasons. As such a fibrous substance, glass fibers, ceramic fibers, Kevlar fibers and the like are exemplified. As these materials, a material, whose thermal expansion coefficient is close to that of a silicon chip as much as possible, is preferable for improving the various reliabilities of a sealing product. Thereby, a resin-sealed semiconductor device, whose package is thin and which has various reliabilities superior to those of a TAB element, is obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a resin-sealed semiconductor device, and particularly to a thin package semiconductor device.

[Conventional technology]

Resin encapsulation technology has been widely used as a packaging technology to protect semiconductor elements from the external environment and facilitate mounting on printed circuit boards. A currently widely used encapsulation method is to encapsulate semiconductor elements using a transfer molding machine using a molding material containing epoxy resin mixed with a large amount of filler and various additives. In recent years, there has been a strong demand for higher density mounting of various semiconductor components due to the need for smaller, thinner, lighter weight, and more sophisticated electronic devices. It is on the rise. In other words, the conventional pancage is a DIP (dual engineering, one-day, one-stick) system in which the bottle is inserted into a through hole on a printed circuit board.
The pin-insertion type, typified by Package), was the mainstream. However, recently, in order to increase the packaging density, SO
P (Small 0utline 1astic P
ackage), S OJ (Small Out 1
ine J-1ead Plastic Package
), Q F P (Quad Flat 1st
There is an increasing demand for surface mount packages such as icPackage, which can be mounted on both sides and are small in size. In addition, the thickness of the package is extremely important, especially when trying to make devices and parts thinner, and recently T
S OP (Thin Small 0ut-1in
eDan1astic Package), TSO
J (Engineering Small Outline J-1e
ad Plastic Package), TQ
F P (Thin Quad Flat Plast)
An ultra-thin package with a thickness of around 111I11 (IC Package) has also been developed. However, in fields such as watches, cameras, calculators, word processors, and personal computers,
Furthermore, thin packages are required, and TAB (Tape Automated Bodies) are used in such fields.
A product with a thickness of Q, approximately 7 to 0.8 m, is used, in which the element is bonded to a copper REIT formed on a polyimide film and sealed with potting resin or coating resin. There is.

[Problem to be solved by the invention]

The TAB element is one of the thinnest among the packages currently in practical use, and it is made by transfer molding using a molding material made of epoxy resin mixed with a large amount of fillers and various additives. Compared to molded products, they have lower reliability in terms of moisture resistance and thermal shock resistance, and their mechanical strength is weaker, making them easier to deform or break when handled roughly. There is the problem mentioned above. In particular, mechanical strength problems are becoming more serious as devices become more highly integrated and functional, and chips become larger.

An object of the present invention is to provide a resin-sealed semiconductor device with a thin package.

[Means to solve the problem]

In order to solve the above problems, the resin-sealed semiconductor device of the present invention includes (1) a resin-sealed semiconductor device in which at least the circuit forming surface of a semiconductor element is sealed with resin; It is characterized by being a material made of organic fibers impregnated with thermosetting resin.

(2) The thermosetting resin impregnated into the inorganic or organic fiber is heat-cured when sealing at least the circuit forming surface of the semiconductor element.

(3) In (1) or (2), the thermosetting resin is a thermosetting resin selected from epoxy resins, silicone resins, polyimide resins, and unsaturated polyester resins.

(4) The resin-sealed semiconductor device according to (3), wherein the epoxy resin comprises a polyfunctional epoxy resin, a phenol novolak resin, and a curing accelerator.

(5) Features a surface-mounted pancage structure according to (1), (2), (3) or (4) in which the thermosetting resin contains inorganic or organic particulate matter.

(6) The particulate material is substantially spherical fused silica or alumina particles (1), (2), (3), (4)
Or the resin-sealed semiconductor device according to (5).

(7) Electronic equipment or equipment equipped with the resin-sealed semiconductor device described in (1) to 6).

A more detailed explanation of the part related to the package structure in this description with reference to the drawings is as follows.

FIG. 1 shows an example in which the circuit-forming surface of a semiconductor element 1 and a reed 3 connected via a hump 2 are simultaneously sealed with a base material 4 made of glass fiber impregnated with a thermosetting resin. FIG. 2 shows an example in which the circuit forming surface of the element 1 and the lead 3 connected via the hump 2 are sealed with two types of base materials 4 of different sizes in order to eliminate the step difference in the sealed portion. FIG. 3 shows an example in which the leads are sealed from above and below for the purpose of reinforcing the lead portion 3.

FIG. 4 shows an example in which the element 1 and the leads 3 are sealed from both the upper and lower directions for the purpose of improving various reliability of the element 1 and reinforcing the leads 3.

[Effect]

In the present invention, a base material made of inorganic or organic fibers impregnated with a thermosetting resin is used to improve sealing workability.
In addition, the wetting and spreading of the resin and the thickness of the sealing layer when the resin is heated and cured are suppressed within a certain range, and the mechanical strength of the cured resin is increased. Examples of such fibrous materials include glass fibers, ceramic fibers, and Kevlar fibers. It is preferable that these materials have a coefficient of thermal expansion as close to that of a silicon chip as possible in order to improve various reliability of the sealed product. In addition, these fibers are preferably woven into a cross-like shape or woven into a non-woven fabric in order to maintain a constant thickness.

Next, as the thermosetting resin to be impregnated into such fibers, epoxy resin, silicone resin, polyimide resin, unsaturated polyester resin, etc. can be used. Each of these resins has advantages and disadvantages, but among them, epoxy resin is particularly useful because it has an excellent balance of moldability, physical properties of cured products, and reliability of sealed products. This epoxy resin can use various compounds such as phenol novolac resin, polycarboxylic anhydride, amine, imidazole, and boron trifluoride compounds as a curing agent, but among these, compositions using phenol novolak resin as a curing agent are particularly suitable. Excellent balance of moldability, physical properties of cured product, and reliability of sealed products. Since the curing reaction of these epoxy resins is relatively slow, it is usually necessary to add a curing accelerator to accelerate the curing reaction.

As curing accelerators useful in applications such as the present invention, compounds selected from nitrogen-containing basic compounds, phosphorus-containing basic compounds, or tetra-substituted boron salts of these compounds are useful. The nitrogen-containing basic compound is specifically imidazole and its derivatives or 8-diazabicyclo (D+4+ ○
)-undecene and its derivatives. Examples of the phosphorus-containing basic compound include triphenylphosphine, triethylphosphine, tributylphosphine, trimethylphosphine, tri(p-methylphenyl)phosphine, and tri(nonylphenyl)phosphine. Furthermore, tetra-substituted boron salts of nitrogen-containing basic compounds and phosphorus-containing basic compounds include imidazole and its derivatives, 1,8-
Examples include diazabicyclo(5°4.0)-undecene and its derivatives, and tetra-substituted boron salts of organic phosphonium compounds. Two or more types of these curing accelerators can also be used in combination.

On the other hand, inorganic or organic particulate materials can be used as fillers in the resin component. Such fillers may include fillers such as fused silica, crystalline silica, and alumina, which have a small thermal expansion coefficient and high rigidity, as well as various plastic powders and beads.

Next, various flexibilizing agents can be added to the molding resin composition of the present invention. In particular, when such a flexibilizing agent is blended into a thermosetting resin, not only the thermal shock resistance of the sealed product is improved, but also thermal stress due to a decrease in elastic modulus can be reduced. Specifically, the flexibilizing agent is a silicone compound,
Thermoplastic elastomers such as silicone rubber, polybutadiene rubber, and polyester rubber, and thermoplastic resins such as polyether sulfone and polyetherimide can be used, but silicone-based flexibilizing agents impart water repellency to the resin composition. Because of this, it is also possible to improve the moisture resistance reliability of the sealed product.

In addition, the present invention may optionally contain a camping agent for improving the adhesion between the resin component and the fibrous substance, filler, chip, lead frame, etc., and a molding agent for releasing the molded product from the mold. A release agent, flame retardant, coloring agent, etc. for improving the moldability may be added within a range that does not impair the purpose of the invention.

The fibrous material is impregnated with such a resin component by immersing the fibrous material in an organic solvent in which the resin component is dissolved or dispersed.

At that time, the amount of resin to be impregnated can be adjusted by changing the concentration of the organic solvent. The fibrous material impregnated with the resin component is dried in a temperature range where the thermosetting resin will not harden, and the organic solvent is removed by drying under reduced pressure if necessary.
It is cut to the required size and used for sealing. Although various methods can be considered for sealing a semiconductor element, one example is shown in FIG.

〔Example〕

[Examples 1 to 4] As an epoxy resin, 85 parts by weight of 0-cresol novolac type epoxy resin (epoxy equivalent: 198,150°C melt viscosity: 18 poise) and brominated bisphenol A
15 parts by weight of type epoxy resin (epoxy equivalent: 400, melt viscosity at 150°C: 1.2 poise), phenol novolac resin (hydroxyl equivalent: 10G, 150°C) as a curing agent.
Melt viscosity: 0.8 poise) 52 parts by weight, 2 parts by weight of tetraphenylphosphonium tetraphenylborate as a curing accelerator, 10 parts by weight of polydimethyl silicone modified with amines at both ends (degree of polymerization of about 100) as a flexibilizing agent, coupling A solution was prepared by mixing 2 parts by weight of epoxy silane as an agent, 5 parts by weight of actimon dioxide as an N combustion aid, and 2 parts by weight of carbon blank as a coloring agent with 20 parts by weight of methyl ethyl ketone, and a glass with a thickness of 100 μm was mixed in this solution. The cloth was soaked for 5 seconds. The removed glass cloth was dried at 80°C for 15 minutes to obtain a base material for sealing. Next, using these base materials, aluminum zigzag wiring was formed on the surface using the four methods shown in Figures 1 to 4. The semiconductor element (chip size 2: 8 x 8 m) formed thereon was sealed. The resin was cured by heating at 180°C for 9 minutes using the equipment shown in Figure 5. After the resin was precured, the sealed product was removed from the equipment, and then main curing was performed at 180°C for 9 hours in a thermostatic oven. I did it.

[Examples 5 and 6] As epoxy resins, 85 parts by weight of 0-cresol novolac type epoxy resin (jLt per epoxy: 198, 150°C melt viscosity = 18 poise) and brominated bisphenol A type epoxy buffing fat (epoxy equivalent: 400 , 150°C melt viscosity: 1.2 poise) 15 parts by weight, phenol novolac m fat (jL per hydroxyl group: 106) as a curing agent,
150''C7s melt viscosity: Q, 8 poise) 52 parts by weight, 2 parts by weight of tetraphenylphosphonium tetraphenylborate as a curing accelerator, polydimethyl silicone modified with amines at both ends (degree of polymerization about 100) as a flexibilizing agent 10
150 parts by weight of spherical fused silica with an average particle diameter of 6 μm as a filler, 2 parts by weight of epoxy silane as a camping agent, 5 parts by weight of antimony dioxide as a flame retardant aid, and 2 parts by weight of carbon blank as a coloring agent. A solution was prepared by mixing this with 300 parts by weight of methyl ethyl ketone, and a glass cloth with a thickness of 100 μm was immersed in the solution for 5 seconds. The glass cloth taken out was dried at 80° C. for 15 minutes to obtain a base material for sealing. Next, using this base material, semiconductor elements were sealed using two methods shown in FIGS. 2 and 4. The resin was cured at 180°C in the same way as above using the equipment shown in Figure 5.
After pre-curing the resin by heating for - minutes, the sealed product was taken out from this device and further heated at 180°C in a thermostatic oven.
The main curing was carried out for an hour.

[Comparative Example 1 As a coepoxy resin, 85 parts by weight of 0-cresol novolac type epoxy resin (epoxy equivalent: 198,150·C melt viscosity: 18 poise) and brominated bisphenol A
15 parts by weight of type epoxy resin (epoxy equivalent: 400,150'C melt viscosity: 1.2 poise), phenol novolac resin (hydroxyl equivalent: l○6,150°) as a curing agent
C melt viscosity = 0.8 poise) 52 parts by weight, 2 parts by weight of tetraphenylphosphonium tetraphenylporate as a curing accelerator, 10 parts by weight of polydimethyl silicone modified with amines at both ends (degree of polymerization of about 100) as a flexibilizing agent, filling Using spherical fused silica with an average particle size of 6 μm as the agent,
A solution was prepared by mixing 300 parts by weight of methyl ethyl ketone with 2 parts by weight of epoxysilane as a coupling agent, 5 parts by weight of antimony dioxide as an iliization aid, and 2 parts by weight of carbon black as a coloring agent. Next, this solution was applied to the circuit forming surface and the lead of the semiconductor used in the example, and the temperature was increased to 80°C/30 minutes + 1.20°C/30 minutes + 150°C.
C./30 minutes + 180.degree. C./- hour heat curing was performed to form a coating film with a thickness of about 100 .mu.m. For each semiconductor device thus obtained, the mechanical strength, temperature cycle resistance, and moisture resistance of the chip were evaluated.

As a result, as shown in Table 1, it was confirmed that the resin-sealed semiconductor of the present invention was extremely excellent in various reliability.

〔Effect of the invention〕

The resin-sealed semiconductor of the present invention has an extremely thin package like the conventional TAB element, and has various reliability levels of TA.
Superior to B element. Therefore, the resin-sealed semiconductor device of the present invention is effective in reducing the size and thickness of electronic components and electronic devices that require a high degree of reliability.

[Brief explanation of the drawing]

Fig. 1 is a cross-sectional view of the circuit forming surface of a semiconductor element and the contacts 3 connected via bumps 2 and sealed with a base material 4 made of glass fiber impregnated with thermosetting resin, and Fig. 2 is a sectional view of the sealed portion. In order to eliminate the difference in level, the circuit forming surface of the element l and the lead 3 connected via the bumps 2 are made of two types of base materials 4 of different sizes.
3 is a cross-sectional view of an example in which the circuit formation surface of the semiconductor element 1 and the REIT 3 are sealed from both the upper and lower sides for the purpose of reinforcing the lead portion 3, and FIG. Element 1, for the purpose of improving various reliability of 1 and reinforcing REET 3.
Further, FIG. 5 is a cross-sectional view of an example in which the leads 3 are sealed from both the upper and lower directions, and FIG. 5 is a cross-sectional view showing the method for sealing a semiconductor device of the present invention. 1... Semiconductor element, 2... Bump, 3... Lead,
4...Base material for sealing, 5=-upper mold, 6...Lower mold. Agent: Patent attorney Katsuma Ogawa. Figure 1 Figure 2 Figure 3 Figure 4

Claims (1)

[Claims] 1. A resin-sealed semiconductor device in which at least the circuit forming surface of a semiconductor element is sealed with resin, characterized in that the sealing resin is a material made of inorganic or organic fibers impregnated with a thermosetting resin. A resin-sealed semiconductor device. 2. The resin-sealed semiconductor device according to claim 1, wherein the thermosetting resin impregnated into the inorganic or organic fiber is heated and cured when sealing at least the circuit forming surface of the semiconductor element. 3. The resin-sealed semiconductor device according to claim 1 or 2, wherein the thermosetting resin is a thermosetting resin selected from epoxy resin, silicone resin, polyimide resin, and unsaturated polyester resin. 4. The resin-sealed semiconductor device according to claim 3, wherein the epoxy resin comprises a polyfunctional epoxy resin, a phenol novolak resin, and a curing accelerator. 5. The resin-sealed semiconductor device of claim 1, 2, 3, or 4 having a surface-mounted package structure, wherein the thermosetting resin contains inorganic or organic particulate matter. 6. The resin-sealed semiconductor device according to claim 5, wherein the particulate material is substantially spherical fused silica or alumina particles. 7. The electronic device or device according to claim 1, 2, 3, 4, 5 or 6, equipped with the resin-sealed semiconductor device.