JPS5970490A - Pb alloy brazing material for semiconductor device - Google Patents

Abstract

PURPOSE:To provide a Pb alloy brazing material for a semiconductor device imparted with good wettability and adhesive strength by incorporating specific amts. of Sb and Ag, Sn, In in Pb and limiting the count number of radioactive alpha particles. CONSTITUTION:A Pb alloy brazing material for a semiconductor device consists of 1-15wt% Sb and the balance Pb and unavoidable impurities, contains, if necessary, 1-10% Ag, and 1-65% >=1 kinds of Sn and In and has a characteristic of <=0.5CPH/cm<2> count number of radioactive alpha particles. Such alloy brazing material contains <=50ppb radioactive isotope to avoid receiving the adverse influence of the radioactive isotope. If such alloy brazing material is used for brazing of a sealing plate to a ceramic case, etc. in the stage of assembling a semiconductor device, the generation of a memory error occuring in the brazing material is thoroughly obviated.

Description

[Detailed Description of the Invention] This invention applies not only to ordinary ICs but also to large-capacity ICs:
64KRAM and 256KRAM which are memory elements
etc., and semiconductor devices such as various ultra-LSIs.
□This relates to a PB gold alloy suitable for use as a brazing material for joining parts during assembly.
Generally speaking, as a type of semiconductor device, the
: An IC ceramic pack shown in a schematic vertical cross-sectional view is known. This IC ceramic
The pack □-no mainly consists of a ceramic case l with a predetermined cavity, a silicon chip 2 brazed to the bottom of this cavity, and a binding AQ.
It consists of a wire 3 and a sealing plate 4 which is brazed to the ceramic case 1. Further, in assembling this IC ceramic package, an Au-Sn alloy brazing material or an Au-8i alloy brazing material is used to braze the silicon chip 2 and the sealing plate 4.

As described above, Au alloys are used as brazing materials in semiconductor device assemblies, and while it is true that the use of Au alloy brazing materials increases reliability, it inevitably increases costs. It is something.

Therefore, from the above-mentioned viewpoint, the present inventor has developed a brazing filler metal that has reliability comparable to the Au alloy brazing filler metal conventionally used in the assembly of semiconductor devices, and is cheaper than the Au alloy brazing filler metal. As a result of conducting research to obtain the desired result, it was found that it contained Sb: 1-15% by weight, and further added A as necessary.
g: 1 to 10%, one or both of Sn and In: 1 to 65%, or both, with the remainder consisting of PB and inevitable impurities, and
A PB gold alloy with a radioactive alpha particle count of 0.50 PH (counts/hour)/cI/L or less, which has extremely good wettability when used as a brazing material in the assembly of semiconductor devices. and adhesive strength,
What's more, we learned that it does not cause memory errors and is highly reliable.
Furthermore, this Pb alloy brazing material does not contain expensive components such as Au, so it is extremely inexpensive.

This invention was made based on the above knowledge, and the reason why the component composition was limited as described above will be explained below.

(a) The 5b sb acid component has the effect of further improving the wettability and adhesive strength of the brazing filler metal, but if the content is less than 15%, the desired effect cannot be obtained; If it is included, the workability of the brazing filler metal deteriorates, so its content is set at 1 to 15%.

(b) Ag When the Ag component coexists with Sb, it has the effect of further improving the wettability and adhesive strength of the brazing filler metal, so it is necessary when further improvement in properties is required due to the above effect. However, if the content is less than 1%, the desired effect of improving the above action cannot be obtained, while if the content exceeds 19%, no further improvement effect will be obtained, and the economic efficiency will be reduced. Taking this into consideration, the content was determined to be 1 to 10%.

(c) Sn and In Similar to Ag, Sn and In components have the effect of further improving the wettability and adhesive strength of the brazing filler metal, so they are included as necessary, but if the content is less than 1%. In this case, the desired effect of improving the above action cannot be obtained -J 65. Even if the content exceeds 1% to 65%, further improved suburban fruit will not appear and it will cause higher costs.
It was determined that

(d) Count number of radioactive α particles 5 - PB produced by the normal smelting method contains more than 50 ppb of radioactive isotopes, and this is the count number of radioactive α particles, which is several CPH1cr! ~Several 100 CPH
Corresponds to /crl. When a PB gold alloy material whose main component is PB, which has a high content of radioactive isotopes, is used in the assembly of semiconductor devices, radioactive α particles emitted from the PB gold alloy material may cause memory errors. This can lead to negative effects such as becoming unreliable. Therefore, in order to prevent the adverse effects of these radioactive isotopes from appearing, the content of radioactive isotopes should be set to less than 50 ppb, and the count number of radioactive α particles should be set to 0.
．． It is necessary to keep it below 50PH/crl.

Next, the pb gold alloy filler material of the present invention will be specifically explained using examples.

Example A material with a low content of radioactive isotope, i.e., 0.5 in terms of radioactive α particle count, was prepared using a normal melting method.
Using PB having a characteristic of 0 PH/d or less, the present invention PB alloys 1 to 1 having the component compositions shown in Table 1, respectively, and the SB content falling outside the range of the present invention were prepared. Comparative pb gold alloys were each prepared, and furthermore, they were produced by a conventional smelting method, and therefore had a radioactive α particle count of mass, 4 Cp H
/cffl was used to prepare a comparative PB gold alloy with a composition shown in Table 1, which was cast and rolled into a plate with a thickness of 0.05mm, and from this plate was punched K.
Vertical: 15y1. X width: 10gX width: 1IIl+1! A window frame-shaped brazing filler metal with dimensions of was manufactured.

Next, the resulting window frame-shaped PB gold alloy filling material 1-18 of the present invention and comparative PB gold alloy filling material 1. 2, the first
When assembling the IC ceramic package shown in the figure, it was used to braze the sealing plate to the ceramic case, and the adhesive strength was measured and the wettability was observed. Wettability is marked 0 if the wax completely covers the adhesive surface, and an X if there is even a small part where the wax does not spread.
Evaluation was made using marks. Table 1 also shows the alpha particle counts of the brazing filler metal. Furthermore, the presence or absence of memory errors in the resulting IC ceramic package was also observed.

8 - From the results shown in Table 1, the pb gold alloy fillers 1 to 1 of the present invention
No. 18 showed excellent wettability and adhesive strength compared to Izuku, and the count number of radioactive α particles was also 0, 50 P H/
CI! As shown below, it is clear that there will be no memory errors caused by the moon. On the other hand, the comparative PB gold alloy filling material 1 has a low sb content which is out of the scope of the present invention.

Adhesive strength is low and wettability is poor.

In addition, when Comparative PB gold alloy filler material 2 was used which had a high count of radioactive α particles outside the range of the present invention, memory errors were observed.

As mentioned above, the PB gold alloy filler material of the present invention has excellent adhesive strength and wettability, and the count number of radioactive α particles is 0.50 PH/crl or less, so it can be used in the assembly of semiconductor devices. It is suitable for doing so, and it is also inexpensive.

[Brief explanation of drawings]

FIG. 1 is a schematic longitudinal cross-sectional view of an IC ceramic package. In the drawings, 9-l... Ceramic case, 2... Silicon chip, 3... Bonding AQ wire, 4... Sealing plate. Applicant Mitsubishi Metals Co., Ltd. Agent Tomi 1) Kazuo and one other person 10- Figure 1

Claims (4)

[Claims] (1) Sl:+:: Contains 1 to 15 PH, with the remainder consisting of PB and unavoidable impurities (weight%), and the count number of radioactive α particles is 0.50 PH
A Pb alloy brazing filler metal for semiconductor devices, characterized in that it has a property of /cIft or less. (2) Contains Sb: 1 to 15%, and further contains Ag: 1 to 15%.
10%, with the remainder consisting of PB and unavoidable impurities (wt%), and a semiconductor characterized in that the count number of radioactive α particles is o, 5 CP H/i or less. Pb alloy brazing filler metal for equipment. (3) s'b: Contains 1 to 15%, and further contains S'b.
A composition containing one or two of n and In = 1 to 65%, with the remainder consisting of PB and unavoidable impurities (hereinafter referred to as -L).
weight%), and the count number of radioactive α particles is 0.
A PB gold alloy filler material for semiconductor devices, characterized by having a property of 50 PH/cIi1 or less. (4) Contains Sb: 1 to 15, and further contains Ag: 1 to 1
0% and one or two of Sn and In: 1-
65%, with the remainder consisting of PB and unavoidable impurities (weight%), and the count number of radioactive α particles is 0.50 P H/a! A PB gold alloy filler material for semiconductor devices characterized by having the following properties.