JPH0587182B2 - - Google Patents

Description

[Detailed description of the invention]

(Industrial Application Field) This invention relates to a resin molding material for semiconductor encapsulation. More specifically, the present invention relates to a resin molding material for semiconductor encapsulation that has excellent heat dissipation properties and low stress, reduces the incidence of leak defects, and improves moldability. (Prior Art) As resin molding materials for encapsulating semiconductor devices, materials containing epoxy resin as the main component have been widely used in terms of performance such as moisture resistance and heat resistance, as well as price. In recent years, with the increase in density and integration of semiconductor devices, it has become necessary to improve heat dissipation to reduce thermal fatigue caused by heat generation of devices, and to reduce thermal stress generated between semiconductor devices and sealing resin. It has become necessary to improve moldability and moisture resistance reliability. Improving the heat dissipation of such semiconductor element sealing,
In order to reduce stress, fillers such as crystalline silica and alumina, which have good heat dissipation properties, are generally blended into sealing resin compositions such as epoxy resins. Various attempts have also been made regarding the formulation of these fillers. For example, as an attempt to do this, a method has been proposed (Japanese Patent Laid-Open No. 276816/1983) in which aluminum hydroxide and red phosphorus powder whose surface has been treated with aluminum hydroxide are blended into an epoxy resin. In addition, the inventors of this invention have already proposed the use of silicon nitride filler, which can achieve higher heat dissipation and lower stress than conventional fillers such as crystalline silica and alumina. There is. (Problem to be solved by the invention) However, these fillers have high hardness and must be filled in a large proportion of the encapsulation molding material, so they are not mixed during the kneading process or molding process of the encapsulation molding material. This causes wear on machines and molds, increases the magnetic component in the molding material for sealing, and causes leakage defects. In addition, high filling of these fillers increases the viscosity of the sealing molding material, which causes deterioration of moldability such as wire deformation, fading, or unfilled areas. Various studies have been conducted to date on the occurrence of leakage defects due to an increase in the magnetic component and the decrease in moldability due to the increase in the viscosity of the sealing molding material.For example, regarding alumina filler, It has been found that it is effective to make the shape spherical. However, alumina fillers reduce the moisture resistance of the seal and are therefore problematic in practical use, while no effective method has been found for crystalline silica or silicon nitride fillers. For this reason, the reality is that it is not possible to satisfactorily achieve the goals of improving heat dissipation and reducing stress by filling with filler, and at the same time preventing the occurrence of leak defects and improving moldability. This invention was made in view of the above circumstances, and it improves the drawbacks of conventional resin molding materials for semiconductor encapsulation, has excellent heat dissipation properties and low stress for encapsulation, and has a magnetic component. It is an object of the present invention to provide a resin molding material for semiconductor encapsulation, which reduces the incidence of leak defects without increasing the viscosity and improves moldability by lowering the viscosity. (Means for Solving the Problems) In order to achieve the above object, the present invention provides a resin for semiconductor encapsulation which is formed by blending an inorganic base material mechanochemically coated with the same type of resin as the encapsulation resin as a filler. Provide molding materials. That is, in order to improve heat dissipation and reduce stress in semiconductor encapsulation, it is effective to mechanochemically coat the filler surface with the same type of resin as the encapsulation resin, This resin coating can prevent magnetic components from being mixed into the resin molding material for sealing, effectively suppressing the occurrence of leakage defects, and can also reduce the viscosity of the resin molding material for sealing. This was based on the knowledge that moldability can be significantly improved because of this. As the inorganic base material used in this invention, those that have been widely used as fillers can be used. Particularly preferable inorganic base materials include crystalline silica and/or silicon nitride,
The entire amount may be made of crystalline silica or silicon nitride,
It may be used in combination with other inorganic base materials. The particle size of the inorganic base material is preferably about 1000 μm or less so that a mechanochemical resin coating can be suitably applied. The resin mechanochemical coating method that can be adopted in this invention is a method in which an inorganic base material is surface-treated with a resin by using a pulverization device used as an ultrafine powder pulverizer. For example, as shown in Figure 1, due to the strong compression force and frictional force of the crushing processing equipment,
By coating the resin 2 on fine inorganic base material particles 1 having a particle size of 20 μm or less, or even 5 μm or less, it becomes possible to impart great fluidity. There are no particular restrictions on the equipment that can be used for this mechanochemical coating, but examples include an ONG mill manufactured by Hosokawa Micron Co., Ltd. and a CF mill manufactured by Ajibe Kosan as ultrafine powder crushers. Further, the resin used for this mechanochemical coating is the same type as the base resin of the semiconductor encapsulation molding material, and for example, epoxy resin or the like can be used. In this mechanochemical coating,
An inorganic base material may be surface-treated in advance with a silane coupling agent or silicone oil, and then coated with a resin. If the surface is treated in advance with a coupling agent such as alkoxysilane, epoxysilane, or aminosilane or silicone oil, the moisture resistance of the seal can be improved and the incidence of leakage defects can be further reduced. In the molding material for semiconductor encapsulation of the present invention, as the base resin compounded with the filler, conventionally known epoxy resins known to have good performance such as moisture resistance and heat resistance can be used as appropriate. For example, examples of the epoxy resin include novolac type epoxy resin, bisphenol A type epoxy resin, bisphenol F type epoxy resin, alicyclic epoxy resin, and halogenated epoxy resin. Further, as a curing agent, a conventionally used curing agent such as a novolak type phenolic resin can be used. In particular, suitable curing agents for novolak type phenolic resins include those having two or more phenolic hydroxyl groups in one molecule. As described above, the resin molding material for semiconductor encapsulation of the present invention is a composition in which a conventional semiconductor encapsulation composition containing an epoxy resin or the like as a resin component is mechanochemically coated with a resin as a filler. However, various other additives may be added as long as they do not impair the properties of the sealing resin. For example, silicone modifiers, flame retardants, curing accelerators, mold release agents, colorants, fillers, and the like can be blended as appropriate depending on the type and use of the semiconductor element. Further, as a method for encapsulating a semiconductor using the resin molding material for semiconductor encapsulation of the present invention, a conventional method can be appropriately employed depending on the semiconductor element to be encapsulated. (Function) The resin molding material for semiconductor encapsulation of the present invention mechanochemically coats the surface of the filler with a resin to improve the heat dissipation properties of semiconductor encapsulation and achieve low stress properties. Even if the material is highly filled, it is possible to prevent leak failure due to an increase in the magnetic component and deterioration of moldability due to high viscosity. (Example) Hereinafter, the molding material for semiconductor encapsulation of the present invention will be specifically described with reference to Examples. Example 1 A phenol novolak type curing agent was blended into a cresol novolak type epoxy resin as a curing agent,
As a filler, crystalline silica (maximum particle size 850 μm,
85wt% of the above cresol novolac type epoxy resin mechanochemically coated at a weight ratio of 10:1 (average particle size 8μm)
This was added to prepare a resin molding material for semiconductor encapsulation. A semiconductor element was encapsulated using the obtained resin molding material for semiconductor encapsulation, and the thermal conductivity of the encapsulation, melt viscosity at 150°C, magnetic content, moldability, initial leak failure rate, and PCT (5at% 100% RH 100
The incidence of leakage defects after 3 hours was evaluated. In this case, the magnetic content was determined by an automatic magnetic analyzer (MAONE TIC ANALYZER). In addition, regarding the evaluation of the leak defect incidence rate, NOS TEG (manufactured by Matsushita Electric Works Co., Ltd.) was used as an evaluation element.
Using the measurement circuit shown in Figure 2, the sample was placed in thermostatic oven 1 (100℃), and the time for the leakage current I _DS to reach 10 mA was measured with V _DS = V _GS = 10 V (the switch was not turned on during measurement). sw1 OFF state, switch
sw2 OFF state, sw1 OFF state when not measuring,
switch sw2 ON), the time is less than 100 seconds,
Judgments were made into three levels: 100 to 1000 seconds and those exceeding 1000 seconds, and those exceeding 1000 seconds were considered defective. The results of these evaluations were as shown in Table 1.
As is clear from the comparison with the comparative example described later, the heat dissipation property was good, and the moldability and prevention of leak defects were also excellent. Example 2 Crystalline silica (maximum particle size 700 μm, average particle size
490μm) in advance with a silane coupling agent (0.5wt).
%), and then mechanochemically coated with epoxy resin (average particle size 13 μm) in the same manner as in Example 1 was added as a filler at 85 wt% to prepare a resin molding material for semiconductor encapsulation. A semiconductor element was sealed with the obtained molding material and its properties were evaluated. The results are shown in Table 1. The melt viscosity was low and the magnetic content was small.
Even after PCT, the leak failure rate was significantly lower than in the comparative example. Example 3 Crystalline silica (maximum particle size 800 μm, average particle size
630 μm) was previously surface-treated with silicone oil (0.5 wt%), and then mechanochemically coated with epoxy resin (average particle size 8 μm) in the same manner as in Example 1, and 85 wt% was added as a filler for semiconductor encapsulation. A resin molding material was prepared, a semiconductor element was sealed with the molding material, and its properties were evaluated. The results are shown in Table 1. Similar to Example 2, its characteristics were excellent. Example 4 Crystalline silica (maximum particle size 800 μm, average particle size
630μm) and silicon nitride (maximum grain size 560μm, average grain size
410μm) was previously surface-treated with a silane coupling agent (0.5wt%) at a weight ratio of 1:1, and then mechanochemically coated with epoxy resin in the same manner as in Example 1.
% was added to prepare a molding material for semiconductor encapsulation, and a semiconductor element was sealed with the molding material and its properties were evaluated. The results are shown in Table 1. Similar to Examples 2-3, the properties were excellent. Comparative Example 1 Silane coupling agent (0.5wt%) without mechanochemical coating of epoxy resin
Crystalline silica (average particle size
A resin molding material for semiconductor encapsulation was prepared by adding 85 wt% of 560 μm) as a filler, and its properties were evaluated after encapsulation. The results are shown in Table 1. It has a large melt viscosity and a large magnetic content. The leakage rate was also much higher than in the example. Comparative Example 2 Silane coupling agent (0.5wt%) without mechanochemical coating of epoxy resin
A molding material for semiconductor encapsulation was prepared by adding 45 wt % and 40 wt % of the crystalline silica and silicon nitride of Example 4, which had only been surface-treated in Example 4, and the molding material was encapsulated and its properties were evaluated. The results are shown in Table 1. Similar to Comparative Example 1, the characteristics were poor. Comparative Example 3 In Example 1, the epoxy resin and filler were mixed using a normal Henschel mixer without mechanochemical coating, and 85 wt% of this mixture (average particle size 180 μm) was added to encapsulate the semiconductor. It was used as a molding material. This molding material was used to seal and evaluate its performance. The characteristics were considerably inferior to those of the Examples.

[Table] (Effects of the invention) The molding material for semiconductor encapsulation of the present invention can improve the heat dissipation properties of semiconductor encapsulation, reduce stress, and significantly reduce the incidence of leak defects. In addition, the moldability can be improved. Therefore, by using the molding material for semiconductor element encapsulation of the invention, it becomes possible to perform good resin encapsulation of power transistor devices and highly integrated LSIs.

[Brief explanation of drawings]

FIG. 1 is a process diagram showing a method of mechanochemical coating of resin. FIG. 2 is a circuit diagram showing a circuit for measuring the incidence of leak defects. 1... Inorganic base material particles, 2... Resin.

Claims (1)

[Claims] 1. A resin molding material for semiconductor encapsulation, characterized in that it contains an inorganic base material mechanochemically coated with the same type of resin as the encapsulation resin. 2. The resin molding material for semiconductor encapsulation according to claim 1, which comprises an inorganic base material which has been surface treated with a silane coupling agent or silicone oil and then mechanochemically coated with an epoxy resin. 3. The resin molding material for semiconductor encapsulation according to claim 1 or 2, wherein the inorganic base material is crystalline silica and/or silicon nitride.