JPS5959850A - Alloy for lead frame - Google Patents

Abstract

PURPOSE:To obtain a novel Cu alloy having various suitable characteristics as a material for a lead frame as well as high heat conductivity and heat resistance by adding specified percentages of Si, P, Sn and Zn to Cu. CONSTITUTION:An alloy consisting of, by weight, 0.05-0.2 Si, 0.005-0.015% P, 0.1-1% Sn, 0.05-1% Zn and the balance essentially Cu or further contg. 0.005- 0.05% in total of Mg and/or Ca and/or 0.05-0.5% in total of one or more among V, Nb and Ti is prepared. The alloy has high electric conductivity, a high softening point and favorable mechanical characteristics, and it satisfies requirements as a material for a lead frame of a semiconductor apparatus.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to lead frame materials for semiconductor devices.

Generally, lead frame materials for integrated circuits using semiconductors as elements are required to have the following characteristics.

(1) Good thermal and electrical conductivity.

Excellent thermal conductivity and electrical conductivity are required in order to transmit electrical signals to the circuit section and to promptly release heat generated from the circuit ff14 to the outside.

(2) High mechanical strength Semiconductor devices are ultimately used by inserting the lead tips into the sockets of various circuit boards or by soldering them, so the leads themselves need to have high strength. In addition, the lead portion must have high fatigue strength against repeated bending.

+31 Good heat resistance (high softening temperature).

During the assembly process of semiconductor devices, in each process such as die bonding, wire bonding, and packaging, lead frame materials are exposed to water at temperatures of about 3000 to 400 C, so the heating of the bar L has recently caused the mechanical strength to deteriorate. It is necessary not to do so.

(4) The coefficient of thermal expansion is close to that of the semiconductor chip or mold material.

In order to prevent variations in the properties of the semiconductor chip or deterioration of adhesion with the molding material due to differences in thermal expansion during the assembly process that involves heating, the lead frame material must have r@expansion characteristics similar to those of the semiconductor chip and molding material. be done.

(5) Good workability.

It is necessary to have good molding workability by iJ punching or photoetching, or to have good bending workability of the lead portion.

(6) Good plating properties.

The surface of lead frames is plated with gold, silver, etc. depending on the purpose, so it is desirable that plating with good heat resistance and heat resistance can be easily obtained. 9 However, Fe-42%N, which has been conventionally used as a lead frame material,
i, Fe-Ni such as Fe-29Ni-170o
Ou-based alloys such as Tetsujin copper and phosphor bronze all have advantages and disadvantages, and they have been used depending on the application at the expense of some of the necessary properties.

Among these lead frame materials, Ou-based alloys are
-Thermal conductivity 11-1 electrical conductivity is extremely superior to that of Ni-based alloys, and because it is inexpensive, its usage has begun to increase rapidly in recent years. Alternately, 6-persimmon alloys with improved plating properties have been developed, but none of them simultaneously satisfy the requirements of thermal conductivity, heat resistance, mechanical strength, and plating properties.

In view of these points, the present invention improves the drawbacks of existing copper alloys for lead frames, and provides good heat conduction. The purpose is to provide a new copper alloy that has properties suitable for use in lead frames, having both thermal properties and 4-thermal properties.
0.05-0.2%, Po, 005-0.015%S
An alloy characterized in that it contains 1% to 1% of Zn, 0.05% to 1% of Zn, and the balance substantially consists of O, and furthermore, an alloy containing one or two of the above alloy numbers Mg and OB in total. 0.005-0.05%, Arike V, 11)
and one or more of T1 at a combined N1 of 0.
This alloy is characterized by containing 0.05 to 0.5%.

The present invention will be explained below with reference to Examples.

The alloy having the composition shown in Table 1 is melted in a high frequency melting furnace G trowel,
After casting, hot sweat IJ rolling was carried out at approximately 800L to a thickness of 5 mm, then surface oxide scale was removed by grinding, cold R#F1 rolling and bright annealing were repeated until the thickness was 0.2 mm.
Finished it in 5 minutes. The electrical conductivity, softening temperature, tensile strength, and repeated bending strength of these samples were measured and the results are shown in Table 2.

The approximate bending strength was determined by measuring the number of times until breakage occurred when one side was bent back at 90 degrees, with one round trip of bending back.

As is clear from the results in Table 2, the IJ bronze type (sample % No. 17) has good strength when repeatedly bent (low conductivity), and the iron hook type (sample F No. 1B, 19) Although it has the disadvantage of having good electrical conductivity or weak strength, the present invention has a good electrical conductivity, although it has the disadvantage of weak power (1) electrical conductivity, approximately 60% or more, It can be seen that the lead frame material has a softening temperature of about 400 tl, and has a sticky property as a lead frame material with a softening temperature of about 400 tl and a bending temperature of about 7.

Table 2 Next, the reasons for limiting the range of ingredients in the present invention are described.O8'' and Zn have the effect of increasing the mechanical strength without significantly impairing the electrical conductivity of the alloy, but both are 0.05%.
If it is less than that, the effect is small, and each S10.2%
, if Zn exceeds 1%, the decrease in conductivity cannot be ignored, so Sl is 0.05 to 0.2%, and Zn is 0.05 to 1%.
limited to.

Both P and Sn are effective in improving heat resistance and mechanical strength, but if Po is less than 0.05% and SnO is less than 1%, sufficient heat resistance will not be achieved; , O], 5%, and Sn1% in excess of 1'1, the conductivity decreases too much. ]
, % bound.

Mg and Oa have the effect of increasing the cyclic bending strength by 8%, or by dividing either I+ or both by 0.00.
If it is less than 5%, the effect will be small, and if it exceeds 0.05%, the effect will be saturated, leading to a decrease in conductivity.
And for Oa, either type or both types are 0.
．． It was limited to 0.005% to 0.05%.

V, Nb and Tj are softening temperature and mechanical strength IQ
- 41 [1 or more] If the two words are less than 0.05%, the effect will be small, and if it exceeds 0.05%, the introduction rate will increase. V, Nb and T3- were limited to -fiit or split into two or more ``C0.05 to 0.5% since this would lead to a decrease in cyclic bending strength.

As explained above, the alloy of the present invention has high molar conductivity and sieve softening point, as well as extremely good mechanical properties, j
It exhibits the characteristics of a semiconductor device and has the necessary printing and conditions for binding, and has a remarkable effect.

Agent 1) Hisashi Naka? 8' Procedural Amendment (Mackerel) 1980 1S/Application No. 170537 C; = title of invention, - door, - detailed description of the invention in the specification of the person making the 4 alloy correction.

Claims (1)

[Claims] 1, 'ifi lij% nite, Sj, (1,05~
02! %, PO, 005-0.015%, Sn0.1
~1%, zno, o[-1%, and the remainder is substantially Ou
J, Rinaru lead frame meeting c0 2, jiii% Si0.05 he 0.2%, P
0.005-0.01.5%, 5n01-1%, Zn0
．． 05 = 1%% N Tf1', further contains 0.005 to 0.05% of Mg and -fl of 08 (or the two types together in 81) A bonded frame alloy characterized by the following: 3-layer Sj, 0.05-0.2%, P O, 0
05~O, O15%, SnO, Co~1%, Zn0.05
~1%, the balance being essentially OU &J history v
,NbJ$ J:hi1"One or more of 1"
- f3:tt did not contain 0.05 to 055 4
Characteristic lead part T-M alloy. 4 M (f1%c=: -CS10.05~0.2%
, PO,005~O,O], 5%, F3nO01
~1%, Zn0.05~%, one or two of M6 and Oa at the same time in total 0.005~0.05%
, the remainder is actually OuJ: further V, N) +
and one or more of Ti in a gold phase with 0.0
A glued frame alloy characterized by containing 5-0.5%.