JPH07242981A - Combined member of cbn polycrystal and sintered hard alloy, reduced in resin adhesion - Google Patents

Abstract

PURPOSE:To produce a combined member of CBN polycrystal and sintered hard alloy, reduced in resin adhesion, by constituting a surface layer part of a CBN polycrystal sintered compact of specific composition and also constituting an inner part of low-hardness WC-base sintered hard alloy or TiC- or TiCN-base cermet. CONSTITUTION:A surface layer part is constituted of a CBN polycrystal sintered compact composed of, by volume, 100-60% CBN, 0-40% TiN, 0-20% AlN, O-40% Co, 0-20% Al, 0-40% Ni, and 0-10% Cr and having sufficient thickness, and a WC-base sintered hard alloy or TiC- or TiCN-base cermet, having <=93.0 hardness HRA, is used for the inner part. By this procedure, a combined member of various CBN polycrystals and sintered hard alloy, reduced in resin adhesion and improved in reliability and service life, can be obtained. By forming a pot or plunger for a resin mold for semiconductor devices by using this combined member, a metal mold reduced in resin adhesion and consisting of a hard and corrosion resisting surface and a high-toughness inner part can be obtained.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to various CBN polycrystalline-carbide composite members having reduced resin adhesion and improved reliability and service life.

[0002]

2. Description of the Related Art In the process of mounting an IC on a lead frame, various kinds of carbide punches and dies have been conventionally used. In particular, resin molds are generally used to protect ICs from the environment. Therefore, dies for manufacturing resin tablets, punches, pots for injection molding parts, plungers, gates for resin inlets, resin cuts for removing resin resin. Many punches and the like come into direct or indirect contact with the resin.

However, recently, in order to improve the performance of the resin, a kind of resin having a high content of silica as a filler and generating a large amount of corrosive gas has begun to be used. Therefore, the surface of the cemented carbide member that comes into contact with such a resin is abraded by the hard silica, so that the irregularities are easily peeled off. If the irregularities become severe, the resin easily adheres to the surface of the member, and then the corrosive gas generated from the adhered resin erodes the metal binder portion of the cemented carbide member, which promotes surface damage.

[0004]

As described above, in the conventional cemented carbide, the surface roughness becomes severe due to the hardness of the silica contained in the recent resin and the corrosive gas, which causes the resin to adhere. Dramatically reduces reliability and service life.

[0005]

In order to overcome the hardness of silica, it is ideal that the surface of the member is made of a material harder than the cemented carbide, that is, CBN polycrystal. However, when the whole member is made of CBN polycrystal, the transverse rupture strength and the fracture toughness value are naturally lowered. However, due to the recent tendency to increase the number of pins, there is a tendency for the overall thickness of the members to decrease, starting with the punch.
If a CBN polycrystal is used for such a thin member, the fracture strength and the fracture toughness value are low and the frequency of breakage increases, so that it cannot be put to practical use. The inventors of the present invention have conducted extensive studies on a method of coexisting these contradictory properties in one member. As a result, a CBN polycrystal having a hard surface and corrosion resistance,
The problem was solved by making the inside a superhard or cermet double structure that is rich in toughness. The following is a detailed description according to the claims.

[0006]

When the metal binder in the A portion of the surface layer is used, one or two kinds of Co and Ni are used. Other metals have poor wettability with CBN and cannot be put to practical use. The content of these binding metals is in the range of 0 to 40% by volume. If it exceeds 40%, the hardness is lowered, so that surface irregularities are likely to occur, which is contrary to the gist of the present invention. Particularly in the case of improving the corrosion resistance, it is effective to add Cr, and in this case, the addition amount is 0 to 10% by volume. If it exceeds 10%, the toughness decreases and it cannot be put to practical use. When a part of CBN is replaced with TiN and / or AlN, the toughness of the CBN polycrystalline part is also improved and the reliability is increased. However, an excessive amount of substitution impairs wear resistance, so an appropriate substitution amount is 40% by volume for TiN.
Hereinafter, AlN is 20% by volume or less, and the total amount is 40% by volume or less.

It is also possible to replace part of Co and Ni with Al. The effect of improving toughness and corrosion resistance can be expected. However, excessive substitution lowers wear resistance and toughness, so the upper limit is 20% by volume. Further, the thickness of the portion A is defined by the application, and if it is too thin, sufficient abrasion resistance cannot be ensured and unevenness is likely to occur, which is contrary to the gist of the present invention. On the other hand, if it is too thick, the wear resistance can be secured, but the fracture toughness value is lowered, and it tends to be broken, which also goes against the gist of the present invention. The internal B part is WC-based carbide or cermet having a hardness of HRA 93 or less. By setting the HRA to 93 or less, the toughness can be secured, and even when it is used as a thin member, the frequency of breakage is small and it can be practically used.

As a method of forming the double structure of the part A and the part B, silver brazing is sufficient for the purpose of the present invention when the temperature rise is small and the load is small. Further, when it is desired to secure the bonding strength, the purpose can be achieved by superposing the part A constituent part and the part B constituent part and bonding them by electric heating. In this case, a good effect can be obtained in which a metal thin piece or an unsintered cemented carbide press body is inserted into the joint portion and electric current welding is performed. Specifically as a composite member, a resin mold pot, a plunger,
A die for resin tablet molding, a punch, a gate installed at a mold inlet, a resin cut punch and a die for removing resin resin are liable to be directly and indirectly affected by the resin due to its application, and the improvement effect thereof by the application of the present invention. large.

[0009]

EXAMPLE A CBN polycrystal body prepared by mixing and molding into a predetermined composition or sintering after molding was prepared for part A. Further, raw material powders such as WC, Co and Cr for the B part were weighed in a predetermined ratio and wet-mixed for 72 hours in a ball mill using alcohol as a dispersant. Next, the mixed powder was dried by spray drying, granulated, and then press-molded into a predetermined shape. The molded body thus obtained is overlaid with that for the part A and sintered (treatment 1), or silver brazing after sintering (treatment 2), or electric heating after sintering (treatment 3), or metal The thin body was inserted between two types of sintered bodies and joined by means of heating by heating (treatment 4) or the like. The joining member thus obtained is provided with a resin molding pot, a plunger, a resin tablet molding die, a punch, an IC resin mold die gate, a resin cut punch, and a resin molding pot such that the portion A is a contact portion with the resin. A die was prepared and compared with the conventional product, and the resin adhesion state, breakage frequency and abrasion resistance were investigated.

[0010]

[Table 1]

[0011]

[Table 2]

[0012]

[Table 3]

[0013]

As described above, various mold members using a double-structured composite member having a CBN polycrystal-cemented carbide composite material on the surface and a cemented carbide alloy with a slightly increased amount of binding metal inside have resin adhered thereto. It is possible to obtain the property that the number of breakage is small, the frequency of breakage is small, and the abrasion resistance is high.

Claims (10)

[Claims] 1. A surface layer portion (hereinafter abbreviated as A portion) having a sufficient thickness is CBN; 100-60% by volume TiN; 0-40% by volume AlN; 0-20% by volume Co; 0-40% by volume Al; A CBN polycrystalline sintered body composed of 0-20% by volume Ni; 0-40% by volume Cr; 0-10% by volume.
(Abbreviated as "part") is a WC-based cemented carbide having a hardness of HRA 93.0 or less, or a TiC or TiCN-based cermet, and a CBN polycrystalline-cemented carbide composite member with reduced resin adhesion. 2. A CBN multi-conductor having reduced resin adhesion, characterized in that a pot or a plunger for resin molding of a semiconductor element (hereinafter abbreviated as IC) is wholly or partly formed of the cemented carbide member according to claim 1. Crystal-Cemented Carbide composite member. 3. A CBN polycrystal with reduced resin adhesion, characterized in that the die or pestle for molding a resin tablet for resin molding of IC is entirely or partially formed of the cemented carbide member according to claim 1. -Cemented carbide composite member. 4. A resin adhesion characterized in that all or a part of a gate part (hereinafter abbreviated as a gate) into which a resin for a resin mold of an IC is injected is made of the cemented carbide member according to claim 1. CBN polycrystalline-hard alloy composite member with reduced 5. The punch or die (hereinafter abbreviated as resin cut punch or die) for removing the resin adhering in the step of mounting the IC on the lead frame is entirely or partially formed of the cemented carbide member according to claim 1. A CBN polycrystalline-cemented carbide composite member with reduced resin adhesion characterized by the following. 6. The method according to claim 1, wherein at least one of the constituent elements of the A or B portion has a concentration gradient in the vicinity of the boundary between the A and B portions shown in claim 1. CBN poly-crystalline cemented carbide composite member with reduced resin adhesion 7. A CBN polycrystalline-cemented carbide composite member with reduced resin adhesion, characterized in that the A part and the B part shown in claim 1 are joined by silver brazing. 8. A CBN polycrystalline-cemented carbide composite member with reduced resin adhesion, according to claim 1, wherein part A and part B of claim 1 are joined by an electric heating method. 9. The CBN polycrystalline-carbide composite member according to claim 8, wherein a metal foil piece is inserted between the A portion and the B portion. 10. The CBN polycrystalline-carbide composite member according to claim 1, wherein the A part and the B part are sintered and joined.