JPH0635517B2 - Semiconductor encapsulation resin - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention relates to a seal for encapsulating a semiconductor device such as a high density integrated circuit (hereinafter referred to as LSI) or a super high density integrated circuit (hereinafter referred to as VLSI). Regarding stop resin.

[Prior Art and Its Problems] Resin encapsulation of a semiconductor device has been conventionally performed in order to protect a semiconductor chip (hereinafter referred to as a chip) from external mechanical shock, moisture, dust, heat, etc. In recent years, a low-pressure transfer molding method using an epoxy resin or a silicone resin has become mainstream as a resin sealing method for a semiconductor device. A chip and a chip are mounted on the sealing resin used in the low-voltage transfer molding method. Inorganic powder such as silica or alumina is added as a filler in order to relieve the molding stress caused by the difference in the coefficient of thermal expansion from the lead frame or to improve the mechanical and thermal characteristics of the sealing resin.

However, due to recent breakthroughs in ultra-fine processing technology for various elements and aluminum wiring formed on the chip surface,
As a result of ultra-miniaturization and high integration of SI and VLSI, these semiconductor devices become more sensitive to external stimuli, and the stress generated from the corners of the filler contained in the resin, which has had almost no effect in the past, is generated. There is a problem that elements and wirings on the surface of a chip are damaged by deformation or microcracks, which adversely affects the function of the chip.

That is, today, ultra-miniaturized or highly integrated LSI
While the wiring width of VLSI and VLSI is about 1 to 3 μm, the particle diameter of the filler 4 existing in the sealing resin is 150 when converted to the maximum Stokes diameter as shown in FIG.
Up to about 200 μm (however, there is no particle having a size larger than the opening size of the gate of the mold, that is, particles having a particle size of about 200 μm or more) and having a square shape,
When the corner comes into contact with the passivation film that protects various fine elements and wiring on the chip surface, the corner of the filler particle is strongly extruded to the surface of the chip due to the molding shrinkage of the surrounding matrix resin. Are concentrated in this corner, especially when the size of the filler particles is large,
The stress becomes extremely large, and the stress caused by breaking or compressing or shearing a very thin passivation film causes damage such as cutting or deforming the element or wiring, resulting in problems such as chip malfunction or moisture resistance failure. Occur.

In order to relieve 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 amount of filler, and for that purpose a filler having a wide particle size distribution from large particles to very small particles is preferable, and such a filler is contained. The encapsulating resin has good fluidity at the time of molding and is also effective in preventing the formation of burrs due to the outflow of the resin from the air vent of the mold. Therefore, in this case, naturally, particles having a large particle size are contained, so that even conventional fillers having the above-mentioned various advantages including cost and practical aspects can be used as a sealing resin for semiconductors such as LSI and VLSI. Cannot be applied.

Therefore, a method of rounding the filler particles can be considered in order to relieve the edge stress of the filler. However, particularly in the case of fine particles, it is extremely technically difficult, and there are major problems in terms of cost and practicality.

On the other hand, the method of removing the large particles and using the fine particle filler is difficult to disperse the filler in the sealing resin,
In addition, the fluidity is significantly reduced, the productivity is reduced due to the formation of burrs due to the outflow of the molding resin from the mold air vent, and the yield is reduced, that is, the dead time and burrs required for removing burrs adhering to the mold. If the removal is not complete, it will bite the burr at the next sailboat and cause a serious problem such as poor appearance.

[Problems to be Solved by the Invention] Therefore, the inventors of the present invention have conducted extensive studies to obtain a semiconductor encapsulating resin capable of solving such problems, and found that large particles having a round shape and ordinary crushing caused the problems. When a semiconductor is encapsulated with an encapsulating resin containing a filler that is prepared by mixing fine particles, it is an excellent semiconductor encapsulator that does not reduce reliability such as chip malfunctions and moisture resistance defects, and productivity and yield. The inventors have found that a stop resin can be obtained, and completed the present invention.

[Means for Solving Problems] The semiconductor sealing resin according to the present invention has a particle diameter of 200 μm.
The filler contains a particle group consisting of spherical particles having a particle size of 10 μm or more and a particle group consisting of crushed particles having a particle size of less than 20 μm.

[Operation and Examples] Since the semiconductor encapsulating resin according to the present invention has the above-described configuration, it is possible to sufficiently disperse the filler in the matrix resin and prevent a significant decrease in fluidity. It is possible to reduce the edge stress of the filler while preventing the productivity and the yield from being reduced due to the formation of burrs due to the outflow of the molding resin from the air vent of the mold.

Table 1 shows DIP (Dual in-line pa) of 256K DRAM using the epoxy encapsulating resin containing the filler of the present invention.
ckage) is made as a prototype and an operation test thereof is performed.

The filler of the encapsulating resin of Example 2 uses spherical particles having a particle size of 20 μm or more, and crushed fine particles having an ordinary shape having a particle size of less than 20 μm.

Further, the filler of the sealing resin of Example 1 uses spherical particles having a particle size of 10 μm or more.

If the minimum particle size of coarse particles having a normal shape is 20 μm or more, when a LSI or VLSI is resin-sealed, a very thin passivation film may be destroyed, or stress due to compression or shear may cut elements or wirings. It is not preferable because it causes damage such as deformation or deformation and causes problems such as malfunction of the chip and poor moisture resistance.

Therefore, when using a filler having a particle size of at least 20 μm, it is necessary to use a particle having a shape close to a sphere.

From the results shown in Table 1, the semiconductor encapsulating resin of the present invention has no problem such as edge stress due to the filler in the encapsulating resin, and is very excellent in practical use such as moldability, productivity, yield, and cost. It can be seen that it is.

Further, like the conventionally used filler, it is preferable to use a filler having a wide particle size distribution from the viewpoint of fluidity and moldability, but the maximum particle size of the filler to be used is 200 μm from opening size of die gate
It is preferably about the same.

As the material of the filler, those conventionally used can be used, and specific examples thereof include silica,
Alumina, magnesia, boron nitride, silicon carbide and the like can be mentioned, and among these, silica is particularly preferable because it is excellent in purity and cost.

Further, in order to make the shape of the filler, which is a relatively large particle having a particle diameter of 20 μm or more, as described above into a spherical shape, a conventional method such as dropping in high temperature plasma can be used as it is. There is no problem, and as a sealing resin, it is possible to obtain a resin that is superior in fluidity and mold wear to conventional fillers.

Further, as the encapsulating resin base material used in the present invention, conventionally used epoxy resin or silicone resin can be used, but the resin contains 30 to 90% by weight, particularly 50 to 80% by weight of filler. Preferably.

EFFECT OF THE INVENTION The semiconductor sealing resin according to the present invention has a particle size of 200 μm.
Dispersion of the filler in the matrix resin, since it contains a filler composed of spherical particles having a particle size of 10 μm or more and crushed particles having a particle diameter of less than 20 μm. Since the edge stress of the filler can be relaxed while ensuring the fluidity and fluidity of the sealing resin and preventing the occurrence of burrs, the semiconductor has high productivity and yield, and is highly reliable without malfunction or moisture resistance failure. The device can be obtained.

[Brief description of drawings]

FIG. 1 is a sectional view of a semiconductor device for explaining a distribution state of a filler in a DIP resin-sealed with a conventional sealing resin. In the figure, 1 is a semiconductor chip, 2 is a die pad, 3
Is a sealing resin, 4 is a filler, 5 and 6 are gold wires, 7 and 8
Is a lead.

Front page continuation (72) Inventor Osamu Nakagawa 4-1, Mizuhara, Itami City, Hyogo Prefecture Mitsubishi Electric Corporation Kita Itami Works (56) References JP-A-60-124647 (JP, A) JP-A-53-102361 (JP, A)

Claims (1)

[Claims] 1. A filler comprising a group of particles composed of spherical particles having a particle size of 200 μm or less and 10 μm or more and a group of particles composed of crushed particles having a particle size of less than 20 μm. Semiconductor encapsulation resin to be.