JPS6033328A - Copper-based alloy for lead frame and manufacture thereof - Google Patents

Abstract

PURPOSE:To manufacture a copper based alloy for lead frame, which is excellent in the characteristics of strength and elongation, by subjecting a copper based alloy rough plate to which are added specific proportions of Ni, Fe and Sn on the basis of Cu to a finish cold rolling process under a specific condition. CONSTITUTION:A copper based alloy rough plate, consisting of 0.05-0.40wt% Ni, 0.5-1.5wt% Fe, 0.5-1.5wt% Sn and Cu as main component with inevitable impurities, is subjected to a finished rolling process with a draft rate of 50% or more and then to annealing process at 250-450 deg.C for 5-60min.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a copper-based alloy having various properties required for semiconductor lead frame materials.

Conventionally, semiconductor devices have been used for adhesives such as Kovar alloy (Fe-29Ni-16Co) and 42 alloy (Fe-29Ni-16Co), which have good adhesion and sealing properties with elements and ceramics.
High nickel alloys such as 42Ni) were preferred. However, as the S density of semiconductor circuits increases in recent years, there is a need to further improve heat dissipation.

Furthermore, in order to reduce costs, the proportion of copper-based alloys used in adhesives has recently increased.

The conventional copper-based alloys for glue include oxygen-free copper,
Sn-containing copper, phosphor bronze + Fe-containing copper, etc. are known, but each has advantages and disadvantages, including mechanical strength, elongation, electrical conductivity, heat dissipation, softening resistance, and plating required for lead materials. In order to comprehensively and fully satisfy various conditions such as performance, soldering, performance and economy, this 1F/1
Desired for base alloys.

The present invention aims to meet this need. For this purpose, the present inventors conducted repeated test and research, and found that Ni: 0.05-0.40%, Fe: (
A copper base metal containing 1.5 to 1.5% by weight and Sn: 0.5 to 1.5% by weight in copper has various properties suitable for Jl'+7+ as a lead frame material. I've come to find out. This copper-based alloy is then finished to the required thickness at a rolling rate of 50% or more during final finishing rolling (cold rolling), and then 25%
It has been found that by annealing at a temperature of 0 to 450°C for 5 to 60 minutes, it exhibits better characteristics as a lead frame material.

The properties of the copper base metal for lead frames of the present invention are as shown in the examples below, but an overview of the reasons for determining the contents of Ni + Fe and Sn, which are alloying elements of the single-base alloy, as described above will be explained below. The explanation is as follows.

Ni provides the effect of improving mechanical strength, softening resistance, and corrosion resistance, but if it is less than 0.05%, this effect cannot be obtained. However, if the content exceeds 0.4%, the N'I conductivity and solderability will deteriorate, as seen in Nos. 9 and 10 of Table 1 below.

Fe serves to improve strength without reducing conductivity. Further, due to the presence of Fe at a concentration below the solid solubility limit, fine iron precipitates precipitated in the copper matrix prevent coarsening of crystal grains during high temperature heating and improve softening resistance. If the Fe content is less than 0.5%, No. in Table 1 below,
5 and No. 6, this strength and 1li
ij The effect of improving the softening property is insufficient. On the other hand, if the Fe content exceeds 1.5%, the tetraelectricity decreases and the processability also deteriorates.

Sn forms a solid solution in the matrix to improve strength and softening resistance. However, if the Sn content is less than 0.5%, positive 7 in Table 1. As seen in No. 8, the improvement effect of 8 strength and softening resistance is not fully manifested. In addition, if the Sn content exceeds 1.5%, the conductivity and thermal transfer properties will deteriorate, and hot workability will also be impaired.

, like 2, Ni: 0.05-0.10% by weight
, Fe: 0.5~1.5% by weight, Sn: 0.5~
By adding 1.5% by weight to copper, the copper-based alloy of the present invention exhibits the properties required for semiconductor ICC REITs. (Cold-rolled sheet) was finished cold-rolled by IJ at a rolling reduction of 50% or more.

When the material is then annealed at a temperature of 250 to 450° C. for 5 to 60 minutes, it can be made into a material with properties that are even more desirable as a lead material, as shown in Table 2 below. In this case, if the final finish rolling reduction is less than 50%, sufficient strength and elongation can be obtained by 1 & subsequent annealing, but finish cold rolling at a rolling reduction of 50% or more (250-450°C)
A combination of annealing (5 to 60 minutes) is required. If the annealing temperature is lower than 250°C or the annealing time is shorter than 5 minutes, elongation will not be sufficient, and if the annealing temperature is higher than 450°C or longer than 60 minutes, the crystal grains will become coarse and the durability will deteriorate. As the softening property deteriorates, the strength also becomes insufficient.

The characteristics of the copper-based alloy for lead frames of the present invention will be described below with reference to typical examples.

Example 1 An ingot made by melting an alloy having the composition shown in Table 1 in a high-frequency vacuum melting furnace was hot-rolled at 850°C to obtain a hot-rolled plate having a thickness of 13 mm. After passing through the pickling process, this hot-rolled sheet is subjected to repeated cold rolling, annealing, and pickling, and is finally finished by 50% cold rolling to achieve +I! 7. Sa0.
A 5 mm cold rolled plate was rolled. Samples were taken from cold-rolled sheets (without final annealing) and the tensile strength and elongation were measured by a tensile test.

Electrical conductivity, bending resistance, and solderability were measured. The electrical conductivity was determined by (%IAC5), which is commonly used as an index for evaluating the thermal conductivity and electrical conductivity of the lead material. Surface J softening property was determined by measuring the temperature at which the hardness after heating the sample for 30 minutes becomes 80% of the hardness before heating (hardness as rolled). Moreover, solderability was evaluated by a solder spread test method. The results are summarized in Table 1.

The following is clear from the results in Table 1.

Even if the content of Ni and Sn is within the range of the present invention, the content of Fe and N is lower than the range specified by the present invention.
2. Strength, conductivity and softening resistance are not sufficient. Ni
Even if the Fe content is within the range of the present invention, the strength and softening resistance of Comparative Example No. 8, in which the Sjj ratio is lower than the range defined by the present invention, is insufficient. Further, even if the contents of Pe and Sn are within the range of the present invention, the conductivity and the JU property of Comparative Examples Nos. 9 and 10, in which the Ni content R7 is greater than the amount defined by the present invention, are decreased. Furthermore, even if the content of the old material was within the range of the present invention, Comparative Example No. 11, in which re and Sn were lower than the amounts specified by the present invention, had poor softening resistance and soldering properties.

On the other hand, inventive examples No. 1 to Positive 4 containing Ni, Fe, and Sn within the range specified by the present invention all have good strength, elongation, electrical conductivity (%IAC5), softening resistance, and solderability. It is.

Example 2 No. 4 of Example 1. The Na5 and N[110 alloys were cold rolled to a thickness of 0.25 mm at the final rolling rate shown in Table 2 in the final cold rolling to achieve the final thickness, and then subjected to the annealing conditions shown in Table 2. When final annealing is carried out (
(or not), each sample was taken and the tensile test value and electrical conductivity were measured. The results are shown in Table 2.

Table 2 From the results shown in Table 2, it can be seen that the alloy of the present invention can obtain high strength and elongation when subjected to appropriate final annealing with a final working ratio of 50% or more. For example, as seen in Tests No. and D, by combining an appropriate final rolling reduction and annealing conditions, improvements in both strength and elongation were achieved compared to the as-rolled sample of Example 1 (final rolling reduction of 5()%). can be achieved. On the other hand, in the case of comparative alloys, the effect of improving strength is low even with the combination of this final reduction ratio and annealing conditions.

Applicant: Dowa Mining Co., Ltd. Dowa Metal Industry Co., Ltd. Procedure corrector (voluntary) July 17, 1980 Director General of the Patent Office Gakudono Shiga1, Indication of the case 1982 Patent Application No. 1413862, Name of the invention REIT - Copper-based alloy for frames and its manufacturing method 3.1 Relationship with the case of the city commissioner Patent applicant address 8-2 Marunouchi-chome, Chiyoda-ku, Tokyo Name Dowa Mining Co., Ltd. (and one other person) Representative Nishi 1) Yaku 4, Agent 162 Address 83, Ichigaya Yakuoji-cho, Shinjuku-ku, Tokyo Detailed description of the invention in the specification () η 7, Contents of amendment (1), “On page 2 of the specification, lines 1-2” "increase" is corrected to "r increase".

(2) "Glue material" on page 2, line 4 of the specification is corrected to "lead material."

(3) "Required" on page 2, line 9 of the specification is corrected to "required j."

(4) In the bottom line of page 4 of the specification, "strength and elongation" is corrected to "strength".

(5) "As cold rolled" on page 5, line 16 of the specification is corrected to r cold rolled state 1.

(6) The statement "The electrical conductivity was determined by..." on page 5, line 19 of the specification to page 6, line 1 of the specification is amended as follows.

"Thermal conductivity is in a proportional relationship with electrical conductivity, so we evaluated heat transfer by measuring electrical conductivity."
Correct to.

(8) On page 6 of the specification, lines 3-4, "Temperature was measured." is corrected to "Evaluation was made by temperature."

Claims (1)

[Claims] (11, Ni: 0.05 to 0.40% by weight, Fe
: 0.5 to 1.5% by weight, Sn: 0.5 to 1.5% by weight, and the balance is Cu and unavoidable impurities. f21. Nj: 0.05-0.40% by weight, Fe
: 0.5-1.5% by weight, Sn: 0.5-1
．． A rough plate of a copper-based alloy consisting of 5% by weight and the balance being Cu and unavoidable impurities is finish cold rolled at a rolling rate of 50% or more, and then rolled at a temperature of 250 to 450°C for 5 to 6 hours.
A method for producing a copper-based alloy for lead frames, comprising annealing for 0 minutes.