JPH0310036A - Lead material for semiconductor apparatus - Google Patents

Abstract

PURPOSE:To obtain the lead material for a semiconductor apparatus excellent in all of heat releasing properties, heat resistance, strength, solderability, adhesiveness in plating, etc., required for a lead material by limiting the dimension of precipitated grains in a copper alloy having specified contents of Ni and Si. CONSTITUTION:A copper alloy for a lead material contg., by weight, 0.4 to 4.0% Ni, 0.1 to 1.0% Si and the balance Cu with inevitable impurities is melted and is transformed into an ingot, which is thereafter hot-rolled to chamfer the surface. Next, the alloy is cold-rolled into prescribed thickness, is thereafter annealed and is subjected to final cold rolling to execute heat treatment under optimum conditions, by which the above lead material contg. <=5mum precipitated grains can be prepd.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a copper alloy suitable for lead material of semiconductor devices such as transistors and integrated circuits (ICs).

[Prior art and problems]

Conventionally, high nickel alloys such as Kovar alloy and 42 alloy have been favorably used as lead materials for semiconductor devices because of their low coefficient of thermal expansion and good adhesion and sealing properties with elements and ceramics.

However, in recent years, with the increase in the degree of integration of semiconductor circuits,
As the number of high-power ICs increases, the lead wires used are also made of copper-based alloys, which have good heat dissipation and thermal conductivity.

However, as a lead wire, it has good thermal conductivity, good heat resistance, good solderability, good plating adhesion, and high strength.
Corrosion resistant. It is necessary to satisfy a wide range of conditions such as being inexpensive.

[Means for solving problems]

Therefore, the applicant first developed a copper alloy that was inexpensive and had excellent properties (Japanese Patent Application No. 55-183967 → Japanese Patent Application No. 57-1
09357, patent application 1984-1630 → 1984-11
However, in the present invention, in order to use this alloy as a lead material for semiconductor devices, it is necessary to strictly adjust the size of precipitated particles, and in particular, to improve soldering properties and plating adhesion. found that it is necessary to reduce the size of precipitated particles to 5 μm or less.

The present invention is for semiconductor devices in which precipitated particles of a copper alloy for lead material consisting of 0.4 to 4.0% by weight of nickel, 0.1 to 1.0% by weight of silicon, copper, and unavoidable impurities are 5 μm or less. lead material.

The alloy according to the present invention has good heat dissipation, heat resistance, strength, solderability, plating adhesion, etc. all required for lead materials.

[Detailed description of the invention]

Next, the reason for limiting one alloy component will be explained. The reason why the nickel content is set to 0.4 to 4.0% by weight is that if the nickel content is less than 0.4% by weight, even if 0.1% by weight or more of silicon is added, high strength and high strength cannot be achieved. This is because an alloy exhibiting electrical conductivity cannot be obtained, and conversely, if the nickel content exceeds 4.0% by weight, workability and solderability will decrease.

The reason for limiting the silicon content to 0.1 to 1.0% by weight is that when the silicon content is less than 0.1% by weight, nickel is reduced to 0.4'
Even if more than 1.0% by weight is added, an alloy with high strength and high conductivity cannot be obtained, and if the silicon content exceeds 1.0% by weight, the workability and conductivity will be significantly reduced, and soldering will be difficult. This is because the sex also decreases.

The reason why the precipitated particles are set to be 5 μm or less is that if the particle size exceeds 5 μm, solderability and plating adhesion will deteriorate.

Examples will be described below.

〔Example〕

An alloy having the composition shown in Table 1 was melted to obtain an ingot with a thickness of 100 m. Next, the ingot was hot rolled at about 800℃ to a thickness of 7
．． After reducing the thickness to 5 nn, the surface is solidified. Then, it is cold rolled to a thickness of 1.5 mm, annealed at 800° C. for 5 minutes, final cold rolled to a thickness of 0.8 mm, and heat treated at 420° C. for 6 hours.

As for the comparative alloys, the precipitated particles were coarsened as shown in Table 1 by changing the aging treatment and other conditions.

This sample was pickled with 5% by weight sulfuric acid for about 10 seconds, and its tensile strength, elongation, and hardness were measured. For soldering, the solder was immersed in a 230° C. solder bath (60% tin - 40% lead) for 5 seconds using a vertical dipping method, and the state of solder wetting was visually observed. In addition, plating adhesion was determined by silver plating the material surface to a thickness of about 5 μm and heating it at 350°C for 5 minutes.

After cooling, evaluation was made visually based on the presence or absence of blistering.

As shown in Table 1, the alloy according to the present invention has precipitated particles of 5μ
m or less, the alloy has sufficient strength as a lead material for semiconductor devices, and has good solderability and plating adhesion, making the alloy excellent as a lead material for semiconductor devices.

Margin below Full text correction statement October 18, 1999

Claims (1)

[Claims] (1) A semiconductor in which the precipitated particles of a copper alloy for lead material are 5 μm or less, consisting of nickel: 0.4 to 4.0% by weight, silicon: 0.1 to 1.0% by weight, copper and unavoidable impurities; the remainder Lead material for equipment.