JPS58123746A - Copper alloy for lead material of semiconductor device - Google Patents

Abstract

PURPOSE:To improve the bending workability and conductivity by a method wherein the lead material is formed of an alloy containing specified quantity of Cr, Sn and Cu. CONSTITUTION:The alloy for lead material comprises 0.03-0.2wt% of Cr, 0.03- 0.2wt% of Sn and residual of Cu. The strength and heat resistance of the alloy may be improved by means of adding Cr and Sn to Cu without remarkably degrading the conductivity and bending workability proper to Cu. Moreover, with 0.2wt% of P added, the strength and heat resistance of said alloy may be further improved. However, the content of Cr and Su exceeding respective upper limit remarkably degrades the conductivity of alloy while the content of P exceeding the upper limit thereof degrades both conductivity and workability of the alloy.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a copper alloy for use as a semiconductor V element and as a bonding material for equipment;
It has particularly good bending workability, and is a conventional lead material.
This invention relates to a copper alloy that has strength and heat resistance that are almost equivalent to Fe-Zm-P alloys, and exhibits far superior electrical conductivity.

In general, devices such as ICs and L8Is that use semiconductor V elements are made of semiconductor pellets, island leads (lead frames), bonding wires, etc. Various types of sealed products are used. The following properties are required for lead materials for these devices.

(11) Good electrical and thermal conductivity.

(2) High strength.

(3) Good bending workability.

(41) Superior heat resistance.

Conventional lead materials for semiconductor devices include Cu-Ni-Co alloy (copper #), Fe-Ni alloy, Cu-8th-P alloy, Cu-p*-Zm-P alloy, etc.
u-N i-('e Gold alloy and Fe-Ni alloy have excellent strength and heat resistance, but have poor electrical conductivity (thermal conductivity).
The drawback is that it is expensive. Further, although the Cu-Fe-Zn-P alloy is relatively inexpensive and has considerable strength and heat resistance, it has the drawbacks of poor electrical conductivity (thermal conductivity) and poor bending workability. Further, although the Cu-8s-P alloy is inexpensive, has excellent electrical conductivity (thermal conductivity), and good bending workability, it has the disadvantage of poor strength and heat resistance.

In view of these concerns, the present invention has been developed as a result of various studies. 1. It has good bending workability, and has almost the same strength and heat resistance as the conventional lead material, Cu-Fe-Zn-P alloy.

In addition, we have developed a copper alloy for lead materials for semiconductor devices that exhibits far superior electrical conductivity (thermal conductivity).

One of these is Cf0.03~0.2wt% (hereinafter wt% is simply abbreviated as %), 8 no, 03~0.
2%, balance C effect≧.

Another aspect of the present invention is croAa→, 2%, S n
It concerns an alloy consisting of 0.03 to 0.2%, 2012% or less, W& part Cu.

In other words, the alloy of the present invention has the strength of one alloy without significantly reducing the electrical conductivity (thermal conductivity) and bending workability characteristic of Cu by adding a small amount of Cr and Sa or Cr and 8n and Pv to Cu. Alloy 1: Compared with the conventional lead material Cu-re-Zll-P alloy "□"i:, it has the same strength and heat resistance. This alloy has electrical conductivity (thermal conductivity) and bending workability.

The reason why the P content is limited as in the upper string is as follows.

Cr content V 0.03-02%, 8n content %-0,
03 to 02%, if any of the additive elements such as kneading is less than the lower limit, the desired strength and heat resistance cannot be obtained, and if it exceeds the upper limit, the strength and heat resistance are improved, but the electrical conductivity decreases. This is because there is a significant In addition, the P content was set to 0.2% or less because adding Pv within this range further improves the strength and heat resistance of the alloy, but if the content exceeds 0.2%, the conductivity This is because not only the thermal conductivity (thermal conductivity) is significantly lowered but also the workability is V″4N.

Examples of the alloy society of the present invention will be described below.

Cuvfs analysis using graphite crucible 2. 8n, Or, and P were added in this order while the negative side was coated with charcoal powder, and this was cast to form the first.・15Q- in the composition shown in the table
An ingot with a length of 25 square meters and a length of 200 square meters was obtained. After cutting the surface of these ingots in 265 directions per side,
The color check method was used to check the surface condition and the soundness of the ingot.

Next, the faceted ingot was reheated and subjected to hot pressing to a thickness of 8 mm and width of 150 mm, and then cold cold pressing and annealing were repeated. ．． Finished as a board with a thickness of 0.3 m. The tensile strength, electrical conductivity, heat resistance, and bending workability of these plates were measured. These results and the soundness of the ingots are also listed in Table 1. For comparison, similar measurements were made on the conventional alloys for lead materials shown in Table il1, and the results were %'llll! It is also listed in Table 1.

Measurement of electrical conductivity and tensile strength is performed using JIS-Hose,
It was conducted based on JIS-22241. Heat resistance was determined by cutting samples from the rolled plate according to JIS-Z2201, heat-treating the samples at various temperatures of 7M degrees in an argon atmosphere for 1 hour, and then conducting a tensile test.

The tensile strength was expressed as a heating temperature (semi-softening temperature) that is 1/2 of the sum of the tensile strength before heat treatment and the tensile strength when completely annealed and softened. In addition, bending workability was determined by cutting out a rectangular test piece with a length of 10 mm and a length of 50 mm from the above-mentioned rolled plate, making a 180 degree close contact at the center of the specimen, observing the condition of the bent portion, and checking that there was no cracking. Smooth ones are marked with an O to indicate good bendability, those with defects such as cracks are marked with an X to indicate poor bendability, and those in between are marked with a △. Furthermore, regarding the soundness of the ingots, those for which no surface defects were found according to the color check method were marked with a vO mark, and the others were marked with a VX mark.

As is clear from Table 1, the tensile strength of the present invention is 842.
~51 hours/-1 conductivity 79-91 ncs, heat resistance 36
It exhibits properties from 0 to 450°C, has good ingot quality and bending workability, and has a conventional alloy Cu-24%F@-0.1.
1 compared to 3%Zn-0.04%P alloy (,419')
It has excellent bending workability, strength and heat resistance comparable to that of
It can be seen that it has far superior conductivity. Furthermore, compared to the conventional alloy Cm-0.15%3n-0.01%P alloy (42G), it is found that it has almost the same electrical conductivity and far superior strength and heat resistance.

On the other hand, the comparative alloys 413 and 415, which have a lower Cr content or f3m content than the composition range of the present alloy, have insufficient tensile strength and heat resistance, and in particular, the comparative alloys with a low 8va content are castable. It can be seen that the soundness and bendability of the lump have deteriorated. In addition, it can be seen that the comparative alloy 414%A16, in which the Cr content or 8wr content is higher than the composition axis □・: of the alloy of the present invention, has sufficient strength and heat resistance, but has a significant decrease in conductivity.

Furthermore, although the P content was higher than the composition range of the present alloy and the N comparison alloy, 41i17, showed considerable strength and heat resistance, the electrical conductivity decreased significantly, and the soundness and bending workability of the ingot deteriorated. I understand that.

As described above, the alloy of the present invention has good ingot quality, excellent strength, heat resistance, and excellent electrical conductivity (thermal conductivity), and is a relatively inexpensive product with good bendability. It is an alloy that has remarkable effects as a lead material for semiconductor devices.

Claims (1)

[Claims] (11CrO,03=-0,2wt%, sno, o!1
A pot alloy for lead material of semiconductor devices consisting of ~0.02 wt% and the balance Cu. +2) Cr0.03~0.2wt%, 8m110
3-(12W1%, PQ, 2WtI%, balance Cu, copper alloy for lead material of semiconductor devices.