JPS62124143A - Sealing resin for semiconductor - Google Patents

Abstract

PURPOSE:To obtain a semiconductor sealant resin usable to (very) large scale integrated circuit, etc., without causing the malfunction of a chip nor lowering the reliability, productivity and yield of the chip, by compounding a filler produced by mixing a large spherical particles with fine particles. CONSTITUTION:A sealant resin matrix (e.g. epoxy resin, silicone resin, etc.) is compounded with 30-90wt%, preferably 50-80wt% filler (e.g. silica, alumina, etc.) produced by mixing spherical coarse particles of >=20mum in diameter and crushed fine particles of <20mum in diameter.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a seal for sealing semiconductor devices such as high-density integrated circuits (hereinafter referred to as LSI) and ultra-high-density integrated circuits (hereinafter referred to as VLSI). Regarding resin stopper.

[Prior art and its problems] Resin encapsulation of semiconductor devices has traditionally been done to protect semiconductor chips (hereinafter referred to as chips) from external mechanical shocks, moisture, dust, heat, etc. In recent years, the mainstream method for resin encapsulation of semiconductor devices has been low-pressure 1-transfer molding using epoxy resins and silicone resins. Inorganic powders such as silica and alumina are added as fillers to alleviate molding stress caused by the difference in thermal expansion coefficient with the lead frame on which the lead frame is mounted, or to improve the mechanical and thermal properties of the sealing resin. There is.

However, with recent significant advances in ultra-fine processing technology for various elements formed on chip surfaces and aluminum wiring, L
As SI and VLSI have become ultra-miniaturized or integrated, these semiconductor devices have become more sensitive to external stimuli. Problems have arisen in that the resulting stress causes damage such as deformation and micro-cranking to elements and wiring on the surface of the chip, adversely affecting the functionality of the chip.

In other words, today's ultra-miniaturized or integrated LSI
Whereas the wiring width of VLSI and VLSI is about 1 to 3-
As shown in Figure 1, the filler (4
) has a maximum particle size of 15 when converted to Stokes diameter.
(However, there are no particles with a particle size larger than the opening size of the mold gate, that is, about 20μ or more). When the filler particles come into contact with the passivation film that protects various microscopic elements and wiring on the surface, the corners of the filler particles are strongly pushed toward the chip surface due to molding shrinkage of the surrounding matrix resin, and the stress is applied to these corners. especially when the particle size of the filler particles is large.
The stress becomes extremely large, and can destroy the extremely thin passivation film, or the stress caused by compression and shearing can cause damage such as cutting or deforming elements and wiring, leading to problems such as chip malfunction and poor moisture resistance. occurs.

In order to alleviate the above edge stress, it is effective to reduce the particle size of the filler particles or to round the shape of the filler particles.

However, reducing the thermal expansion coefficient of the sealing resin,
In order to improve mechanical and thermal properties, it is necessary to fill a large number of fillers, and for this purpose, fillers with a wide particle size distribution from large particles to very small particles are preferable, and materials containing such fillers are preferred. The sealing resin has good fluidity during molding and is also effective in preventing the formation of paris due to the resin flowing out from the air vent of the mold. Therefore, in this case, it naturally contains particles with a large particle size, so even if the conventional filler has the various advantages mentioned above, including cost and practical aspects, it is not suitable for sealing semiconductors such as LSI and VLSI. It cannot be used as a resin.

Therefore, a method of rounding filler particles has been considered in order to alleviate the edge stress of the filler, but this is extremely technically difficult, especially in the case of fine particles, and poses major problems in terms of cost and practicality.

On the other hand, in the method of removing large particles and using fine particle filler, it is difficult to disperse the filler into the sealing resin.
In addition, there is a significant decrease in fluidity, and a decrease in productivity and yield due to the formation of paris due to the outflow of molding resin from the air vent of the mold. If the removal is incomplete, the particles will be chewed during the next shot, causing major problems such as poor appearance.

[Problems to be Solved by the Invention] Therefore, the present inventors conducted intensive research to find a semiconductor encapsulating resin that could solve these problems, and found that large particles with round shapes and normal crushing caused When semiconductors are encapsulated using a encapsulating resin containing a filler prepared by mixing fine particles, it is possible to achieve excellent results without reducing reliability such as chip malfunction or poor moisture resistance, and without reducing productivity or yield. They discovered that the semiconductor encapsulating resin could be replaced and completed the present invention.

[Means for solving the problems] The present invention is based on 20. A and more relate to a semiconductor encapsulating resin characterized by containing a filler system consisting of a group of spherical coarse particles and a group of less than 20 particles a group of crushed fine particles.

[Function and Examples] The filler of the resin used in the present invention contains spherical coarse particles when the number is 20 or more, and 20! If the amount is less than 100%, use crushed microparticles having a normal shape.

If the minimum particle size of coarse particles with a normal shape is 20p or more, it may destroy the very thin passivation film when LSI or VLSI is encapsulated with resin, or stress due to compression or shear may cut elements or wiring. This is undesirable because it causes damage such as bending or deformation, and causes problems such as malfunction of the chip and poor moisture resistance.

Therefore, when using a filler with a particle size of 20 ρ or more, it is necessary to use particles whose shape is close to spherical.

In addition, it is preferable to use a filler that has a wide particle size distribution from the viewpoint of fluidity and moldability, as with conventionally used fillers, but the maximum particle size of the filler used is It is preferable that the size is about 200 mm based on the opening size of the gate of the mold.

As the material of the filler, conventionally used materials can be used, and specific examples thereof include silica,
Examples include alumina, magnesia, boron nitride, and silicon carbide. Among these, silica is particularly preferred because it is excellent in terms of purity and cost.

In addition, in order to make the filler, which is a relatively large particle with a particle size of 20 mm or more, into a spherical shape, conventional methods such as dropping it into high-temperature plasma can be used as is, so filler manufacturing There is no problem with the above, and it can also be used as a sealing resin with better fluidity and mold abrasion than conventional fillers.

Furthermore, as the sealing resin base material used in the present invention, conventionally used epoxy resins, silicone resins, etc. can be used, but the resin contains filler in an amount of 30 to 90% by weight, particularly 50 to 80% by weight. Weight is preferred.

Next, the semiconductor encapsulating resin of the present invention will be explained in more detail based on Examples, but the present invention is not limited to these Examples.

Examples 1 to 2 and Comparative Examples 1 to 3 Each filler shown in the Examples and Comparative Examples in Table 1 was used as a filler for an epoxy sealing resin for a resin-sealed semiconductor device used in a conventional low-pressure transfer molding method. Using epoxy sealing resin containing T 256KDRAH D
We prototyped an IP (Dual 1n-1ine Oackaae) and conducted an operation test. Table 1 shows the malfunction occurrence rate at this time.

[Margins below] -8, No. 1 Table 1 [Note] ■: Conventional filler refers to one in which all particles are in the form of crushed particles.

From the results in Table 1, the semiconductor encapsulation resin of the present invention has no problems such as edge stress due to fillers in the encapsulation resin, and has excellent practical properties in terms of moldability, productivity, yield, and cost. It can be seen that it is.

[Effects of the Invention] When the semiconductor encapsulation resin of the present invention is used, a resin-encapsulated semiconductor having excellent characteristics such as no reduction in reliability such as malfunction of the chip or poor moisture resistance, and no decrease in productivity or yield can be obtained. This has the effect that the equipment can be obtained.

[Brief explanation of drawings]

FIG. 1 shows a cross-sectional view for explaining the distribution state of filler in a DIP resin-sealed using a conventional sealing resin. (Drawing codes) (1) Two semiconductor chips (a: die pad, (3): sealing resin (4): filler (5), (6): gold wire (sword), (8): lead agent Masuo Oiwa 1: Semiconductor chip 4 Nifiler 5, 6: Gold wire 7.8: Lead procedure amendment (voluntary) Showa year, month, day

Claims (1)

[Claims] (1) A semiconductor encapsulation resin characterized by containing a filler system consisting of spherical coarse particles with a diameter of 20 μm or more and crushed fine particles with a diameter of less than 20 μm.