JPS60258945A - Lead for ceramic package ic - Google Patents

Abstract

PURPOSE:To eliminate the damage of ceramic substrates, and to improve the strength, conductivity, and thermal conductivity after brazing, by using Cu containing a specific amount of Ni, Si, Zn, Sn, and Cr. CONSTITUTION:As the material of the lead for a ceramic package IC, substance containing Ni 1.0-5.0wt%, Si 0.2-1.5wt%, Zn 0.05-5.0wt%, Sn 0.1-2.0wt%, and Cr 0.02-0.5wt% and made of Cu in the remaining and inevitable impurities is used. Ni and Si improve the strength; however, an excess in Ni content above 5.0wt% deteriorates the conductivity, and an excess in Si content above 1.5wt% deteriorates the hot-workability. Zn improves the thermal exfoliation-resistance of a plated layer, but an excess in its content above 5.0wt% deteriorates the solderability. Sn improves the strength and the elongation, but an excess in its content above 2.0wt% decreases the conductivity. A Cr content of less than 0.002wt% shows a small effect in improvement of the heat workability, and its content more than 0.5wt% causes the oxidation of the molten metal and deteriorates the castability.

Description

[Detailed Description of the Invention] [Industrial Application Field 1] The present invention relates to a lead wire for a ceramic pancage IC;
More specifically, the brazing terminals are joined under heating at 800 to 900'C to form input/output terminals, and the brazing terminals are connected to plug-in terminals made of a copper alloy with a later via cast hardness of at least 130. Ceramics for integrated circuits called IC1 or pin grid array IC.
This invention relates to lead wires for IC.

[Prior art 1] Generally, the base of a bin grid array IC is made of ceramics, several IC elements are mounted on the surface of the base, and the electrodes of the base and the electrodes of the IC elements are connected via bonding wires. , resistors, etc. are added to form a circuit, and the back side is composed of input/output lead wires corresponding to each electrode on the front side. These lead wires are then joined to metalized electrodes by silver fertilization.

In this way, -Va is a Co Ni-Fe alloy (
F-15 alloy of ASTM standard) or Fe-42Ni alloy (F-30 alloy of ASTM standard) is used.

These F-15 alloy and F-30 alloy have a coefficient of thermal expansion similar to that of ceramics, so it is 800 to 900.
Silver brazing at a temperature of 30°F (°C) has been used because it does not apply thermal stress to the ceramic substrate when it is cooled down to room temperature, so it does not cause damage. Also, F-15 alloy and F-
30 alloy has a Vickers hardness of 13 (1') even after brazing at a temperature of 80 o - 9 fl 1')'C.
It has the advantage of being above.

However, F-15 alloy or F-30 alloy has a low electrical conductivity of 3% IACS, and therefore has a low thermal conductivity, so it is easy to generate Joule heat when used as an IC lead wire. The ability to dissipate the amount of heat generated inside the element is also insufficient. In particular, with the recent increase in the density of IC elements,
The amount of heat generated inside the IC element increases, and P
It has been pointed out that the heat dissipation properties of the -]5 alloy and the F-30 alloy are poor, and there is a demand for materials that can replace these alloys.

Copper alloys can be used to meet this demand, but copper alloys generally have the problem that silver brazing at temperatures of 8 () 0 to 900°C softens and loses strength due to heating. Copper alloys with good strength and heat resistance also have the disadvantage of low electrical conductivity, similar to F-15 alloy or F-30 alloy.
It has α.

1-Problem to be Solved by the Invention 1 The present invention has been made in view of the prior art as explained above, and uses a copper alloy that has a higher thermal expansion than F-15 alloy or F-30 alloy. However, silver brazing does not damage the ceramic base during the subsequent cooling process, and
Even after silver brazing at temperatures of 800-900°C, plug-in package ICs or bin grid array ICs with excellent strength, electrical conductivity, and thermal conductivity can be manufactured.
The present invention provides lead wires for ceramic packaged ICs such as the following.

[Means for Solving the Problems 1] The characteristics of the ceramic package IC lead wire according to the present invention are as follows: Ni 1.0-5.01%, Si 0.2-1.5, Zn.
O, 05-5, Ou+t%, Sn O, 1-2, 0wt
%, CrO,002-0.5u+t%, and the remainder consists of Cu and inevitable impurities.

The lead wire for ceramic package IC according to the present invention will be explained in detail below.

3- First, the components and component ratios of the lead wire for ceramic package IC according to the present invention will be explained.

N1 and Si are elements that improve the strength, and Ni1,
If the Ou+t% or Si is less than 0.2iut%, sufficient strength cannot be obtained, and if the Ni and Si contents are increased, the
Brazing at a temperature of 00 to 900°C provides sufficient strength and improves electrical conductivity, but when the Ni content exceeds 5.0 wt%, these effects are saturated and at the same time the electrical conductivity decreases. becomes worse, and the 81 content is 1.5+uL%
If it exceeds 100%, hot workability deteriorates. Therefore, the Ni content is 1.0 to 5.0 LIlt%, and the S1 content is 0.2
], 5u+t%.

Zn is an essential element for improving the thermal peeling resistance of the tin plating or tin alloy plating layer applied to the surface of the lead wire, and if it is less than 0.05u+t%, this effect will be small; If the content exceeds Ou+t%, the soldering properties will deteriorate. Therefore, the Zn content is 0.05 to 5.0
t%.

Sn is an element that dissolves in Cu to improve strength and elongation, especially at temperatures of 800 to 900°C.
Even after brazing at a temperature of 3, it is necessary to satisfy at least three lead wire bending tests, and if the content is less than 1 ust%, the lead wire bending test number cannot be satisfied. Moreover, if the content exceeds 2.0+t%, this standard is satisfied, but the conductivity decreases. Therefore, the Sn content is 0.1 to 2. Let Ou+t%.

Cr is an element that strengthens the grain boundaries of the ingot and improves hot workability.If the content is less than 0,002 wt%, this effect will be small, and if the content exceeds 0.5+++t%, the molten metal will deteriorate. is oxidized and castability deteriorates. Therefore, the Cr content is set to 0.002-0.5u+t%.

In addition to the elements explained above, Fe, Mn, Co
up to 0.2u+t% and Mg alone or in combination of two or more
, Zr, and Ti may be contained alone or in combinations of up to 1 ust%, since silver brazing will be impaired and properties such as tensile strength, conductivity, and number of lead wire bending tests will be maintained without problems. It is permissible until

Therefore, the lead wire for the ceramic package rC according to the present invention is produced by hot extrusion processing from the copper alloy described in 1.
Although it is manufactured through processes such as cold-open drawing and annealing, there are no particular restrictions on the manufacturing process for this lead wire. Good.

Further, the ceramic package IC lead wire according to the present invention was further heated for 10 minutes at a temperature of 400 to 55 fl'C.
Hardness and electrical conductivity can be improved by performing a heat treatment for ~30 minutes.

The reason why the ceramic package IC lead wire according to the present invention has high hardness and high conductivity even after hard brazing is that it has a high hardness of 400 to 500% during the cooling process after brazing.
This is because the purity of the phase decreases if N i2S i precipitates when passing through the 50°C temperature range.

1 Example 1 Next, a ceramic panqueno IC according to the present invention was used.
J-F line "implementation fil" Theory 11J1t7+/Example The alloy shown in Table 1 was melted under charcoal coating in the air in a Kryptor furnace, and poured into a tilting cast iron book mold.
A field and an ingot with a thickness of 60 mm, a width of 60 mm, and a length of 180 mm were prepared.

The front and back sides of this ingot were milled 5111111 times 8
Hot rolling was carried out at a temperature of 50°C to produce a plate with a thickness of O[Ilm], and from this plate a bar with a diameter of 6+nmφ was machined using a lathe, heated to a temperature of 700°C for 30 minutes, and then rapidly cooled in water. .

Next, after removing scale with sulfuric acid, a wire rod with a diameter of 0.46 mm was produced by swaging in a cold I old oven and drawing.

Commercially available F-15 alloy was used as a comparison material.

Table 1 8- Assuming the conditions for joining these wires to electrodes formed by metallizing ceramics using silver solder such as JISBAg-8, after heating to a temperature of 850°C for 10 minutes, approximately The specimens were cooled to room temperature at a rate of 1/2 min, and then aged at a temperature of 475° C. for 30 minutes, and hardness, conductivity, and lead wire bending tests were conducted.

The results are shown in Table 2.

In the lead bending test, a load of 227 g was suspended on the terminal, the terminal was slowly tilted until it was bent by 90°, and then returned to the normal position.This entire operation was counted as one time, and the number of bends until breakage was determined. However, the R of the gripping part was set to Omen. The following can be seen from Tables 1 and 2.

That is, in the present invention Nos. 1, 2, and 2, the hardness (14V) after silver brazing is 1.30 or more, and the electrical conductivity is 20% l.
The AC rating is 3 or more, and the number of times the lead wire is bent is 3 or more times.

However, in Comparative Example No. 3, the lead wire was bent less than 3 times and did not satisfy the standard, and in No. 4, the conductivity was 3%.
It is as low as lAC3.

Therefore, it can be seen that the lead wire for ceramic package IC according to the present invention is excellent.

[Effect of the Invention 1] As explained above, the lead wire for a ceramic package IC according to the present invention has the above-mentioned configuration, so even though the coefficient of thermal expansion is not close to that of ceramics, , silver brazing at a temperature of 800 to 900°C does not cause any cracking of the ceramic during the subsequent cooling process, there is no need to approximate the thermal expansion coefficients of the ceramic and the lead wire, and the conductivity is low. F-15 alloy or F-1
There is no need to use 1-30 alloy, and brazing is done after 1.
In this case as well, it has excellent effects such as high strength and high electrical conductivity.

12-

Claims (1)

[Claims] Ni 1.0-5.0III%, SiO, 2-1,5
u+t%, Zn 0105-5,0w1%, SnO,
1-2, Ou+t%, Cr 00002-0.5iuL
%, with the remainder consisting of Cu and inevitable impurities.