JPS62274038A - Ni-base bar for semiconductor device - Google Patents

Abstract

PURPOSE:To obtain an Ni-base bar for a semiconductor device improving the heat radiating property of conventional 42 Alloy and the coefft. of thermal expansion of a Cu alloy when used as a lead frame for a semiconductor integrated circuit by providing a composition consisting of a specified amount of Ni and the balance inevitable metallic impurities. CONSTITUTION:This Ni-base bar for a semiconductor device consists of >=99.5wt% Ni and the balance inevitable imetallic impurities. The physical properties of the Ni-base bar are similar to those of metallic Ni and the bar produces marvelous results (see table 1) when used as a lead frame for a semiconductor device. The adhesion of the bar to a plated Ag film can be remarkably improved by lowering the oxygen content to <=50ppm.

Description

[Detailed Description of the Invention] 3. Detailed Description of the Invention [Field of Industrial Application] This invention is applicable to semiconductors 81@! The present invention relates to a jFfJNi base material.

[Conventional technology]

Conventionally, F was used as a lead frame material for semiconductor devices.
Commonly known as 4210i (Fe-42%) whose main component is e-Ni.
An alloy whose main components are Ni) and copper is used.

The main properties required of such lead frame materials are (il, @small expansion coefficient close to that of silicon chips (11), good heat dissipation (ji1)
It has high strength (excellent IVL workability, excellent MM corrosion resistance, and excellent heat resistance, etc.).

The purpose of this characteristic fil is to prevent the chip from cracking due to stress caused by thermal expansion differences caused by heating during the Gui bonding process in which the silicon chip forming the circuit is placed on the lead frame material. 11) is I
This is to avoid failures due to self-heating during actual use of C (integrated circuits), and also for O1θ~Gψ.
It is considered to be a necessary characteristic for practical use of C.

The reason why the above-mentioned 4210i has been mainly used is because
Among these required characteristics, first and foremost is a low coefficient of thermal expansion, which facilitates assembly during mass production. Furthermore, it has many advantages such as high strength and workability, high corrosion resistance and #4f@ property.

However, in recent years, attention has been paid to materials with high electrical conductivity, that is, copper alloys, as an alternative to the 42A-42A steel alloys due to their low cost and the heat generation of ICs themselves due to increased integration.

[Problem that the invention seeks to solve]

In other words, 4210I, which is widely used as a lead frame material for semiconductor devices, has advantages such as a small coefficient of thermal expansion, high strength, workability, corrosion resistance, heat resistance, and excellent adhesion to plastic packages. On the other hand, the above-mentioned steel alloy materials have the required characteristics as close to 4210I as possible, and have high thermal conductivity as their greatest advantage. However, the most important property, the coefficient of thermal expansion, remains essentially unresolved, and we are now forced to rely on packaging technology for IC production.

The present invention solves #11, which is the biggest drawback of the above-mentioned 4270i, that is, the heat dissipation property and the biggest drawback of copper alloy material! This was done to solve the drawback of a large tensile coefficient.

[Means for solving problems]

The present invention basically uses Ni, particularly a Ni strip of which 99.5% or more is an unavoidable component, and improves the heat dissipation properties of the above-mentioned 4210I and the coefficient of thermal expansion of the copper alloy.

That is, the present invention is a Ni base material for semiconductor equipment, which is composed of a Ni component with a weight ratio of 99.5% or more, and the remainder is an unavoidable impurity metal, and is intended to be used as a lead frame for semiconductor AM circuits. be.

In the present invention, the properties themselves generally exhibit the physical properties of the Nii genus itself, and this has been utilized as a lead frame material for semiconductor devices, and surprising results have been obtained. Further, by controlling the oxygen content to 50 ppm or less, the adhesion of the Ag plating on the product strip can be significantly improved.

[For production]

The Ni strip material of the present invention, in which 1.299.5% or more of Ni and the remainder is an unavoidable component, is particularly used as the above-mentioned 421 for semiconductor lead frames.
This significantly improves the drawbacks of 0i and the like.

〔Example〕

Table 1 below compares the characteristics of various materials actually used as lead frame materials for integrated circuits and the strip materials according to the embodiments of the present invention. Table 2 shows a comparison of the characteristics of products using these materials.As is clear from Table 1 above, the materials of the examples of the present invention have thermal conductivity and thermal expansion that are higher than the above-mentioned 4.
It falls somewhere between 270I and copper alloys, and has properties suitable for lead frame strips for semiconductor devices.

In addition, in order to reduce costs in future IC production, A.
Technological innovations such as direct wire bonding of chips and lead frame materials without G plating are expected, and such Ni-based alloys are considered to be useful materials because they inherently have excellent spot weldability.

Next, from the results shown in Table 2, the use of the strip material of the present invention improves the deformation resistance of the lead and prevents breakage of the lead.
00, and the heat generation results of ■C show that it has characteristics close to copper-based.

In addition to these, the Ni-based alloy of the present invention has excellent #4 thermal oxidation properties and seals A4! It improves adhesion with F fat, reduces hygroscopicity compared to conventional prepared alloy materials, and improves IC reliability.

(Effects of the Invention) As described above, this invention uses 99.5% or more Ni, basically Ni itself, as a strip material and uses it as a lead frame for semiconductor integrated circuits, and has the surprising effect of solving the above problems. Therefore, the effect of its industrial use is very large.

Claims (2)

[Claims] (1) A Ni base material for semiconductor devices, characterized in that it consists of a Ni component with a weight ratio of 99.5% or more, the remainder being an unavoidable impurity metal, and is used as a lead frame for a semiconductor integrated circuit. (2) In the above (1), the oxygen content is 50 ppm.
A Ni-based material for semiconductor devices characterized by the following features: