Process for attaching a lead member to a semiconductor device

• US 3,930,306 A
• Filed: 04/24/1974
• Issued: 01/06/1976
• Est. Priority Date: 04/24/1974
• Status: Expired due to Term

• Current Assignee: General Instrument Corporation (CommScope Holding Company, Inc.)
• Original Assignee: General Instrument Corporation (CommScope Holding Company, Inc.)
• Inventors: Goldberg, Monroe B., Voorhis, William B.
• Primary Examiner(s): Tupman, W.
• Application Number:
  US05/463,678
• Time in Patent Office: 622 Days
• Field of Search: 29/588, 29/589, 29/504, 29/590, 29/591, 228/219
• US Class Current: 29/854
• CPC Class Codes: B23K 35/302 Cu as the principal constituent
• CPC Class Codes: H01L 2224/8319 Arrangement of the layer connectors prior to mounting
• CPC Class Codes: H01L 2224/83801 Soldering or alloying
• CPC Class Codes: H01L 23/051 another lead being formed by a cover plate parallel to the base plate, e.g. sandwich type
• CPC Class Codes: H01L 23/3157 Partial encapsulation or coating mask layer used as insulation layer H01L21/31
• CPC Class Codes: H01L 23/3171 the coating being directly applied to the semiconductor body, e.g. passivation layer H01L23/3178 takes precedence
• CPC Class Codes: H01L 23/48 Arrangements for conducting electric current to or from the solid state body in operation, e.g. leads, terminal arrangements ; Selection of materials therefor
• CPC Class Codes: H01L 23/488 consisting of soldered or bonded constructions bump connectors H01L24/01
• CPC Class Codes: H01L 23/4924 characterised by the materials
• CPC Class Codes: H01L 24/01 Means for bonding being attached to, or being formed on, the surface to be connected, e.g. chip-to-package, die-attach, "first-level" interconnects; Manufacturing methods related thereto
• CPC Class Codes: H01L 24/33 of a plurality of layer connectors
• CPC Class Codes: H01L 24/83 using a layer connector
• CPC Class Codes: H01L 2924/00 Indexing scheme for arrangements or methods for connecting or disconnecting semiconductor or solid-state bodies as covered by H01L24/00
• CPC Class Codes: H01L 2924/01005 Boron [B]
• CPC Class Codes: H01L 2924/01006 Carbon [C]
• CPC Class Codes: H01L 2924/01013 Aluminum [Al]
• CPC Class Codes: H01L 2924/01015 Phosphorus [P]
• CPC Class Codes: H01L 2924/01018 Argon [Ar]
• CPC Class Codes: H01L 2924/01019 Potassium [K]
• CPC Class Codes: H01L 2924/0102 Calcium [Ca]
• CPC Class Codes: H01L 2924/01023 : Vanadium [V]
• CPC Class Codes: H01L 2924/01029 : Copper [Cu]
• CPC Class Codes: H01L 2924/0103 : Zinc [Zn]
• CPC Class Codes: H01L 2924/01033 : Arsenic [As]
• CPC Class Codes: H01L 2924/01039 : Yttrium [Y]
• CPC Class Codes: H01L 2924/01042 : Molybdenum [Mo]
• CPC Class Codes: H01L 2924/01044 : Ruthenium [Ru]
• CPC Class Codes: H01L 2924/01047 : Silver [Ag]
• CPC Class Codes: H01L 2924/01057 : Lanthanum [La]
• CPC Class Codes: H01L 2924/01058 : Cerium [Ce]
• CPC Class Codes: H01L 2924/01063 : Europium [Eu]
• CPC Class Codes: H01L 2924/01073 : Tantalum [Ta]
• CPC Class Codes: H01L 2924/01074 : Tungsten [W]
• CPC Class Codes: H01L 2924/01075 : Rhenium [Re]
• CPC Class Codes: H01L 2924/01079 : Gold [Au]
• CPC Class Codes: H01L 2924/01082 : Lead [Pb]
• CPC Class Codes: H01L 2924/0132 : Binary Alloys
• CPC Class Codes: H01L 2924/01322 : Eutectic Alloys, i.e. obtained by a liquid transforming into two solid phases
• CPC Class Codes: H01L 2924/014 : Solder alloys
• CPC Class Codes: H01L 2924/10253 : Silicon [Si]
• CPC Class Codes: H01L 2924/13062 : Junction field-effect transistor [JFET]
• CPC Class Codes: Y10T 29/49169 : Assembling electrical component directly to terminal or elongated conductor

Abstract

A thermally and electrically conductive metal lead member is joined to the refractory metal contact member of a semiconductor device using a brazing alloy comprising on a weight basis about 80-89 percent copper, about 5-15 percent silver, and about 4-6 percent phosphorus. The contact member/semiconductor joint may be formed in an inert atmosphere at the same time and at the same temperature as the contact member/lead member joint.

Claims

1. A process for attaching a lead member to a semiconductor device comprising the steps of

A. providing a lead member formed substantially of a thermally and electrically conductive metal and terminating at one end in a joining surface;

and a semiconductor device comprising a semiconductor body and a contact member formed of a refractory metal extending outwardly from said body and terminating in a joining surface of said refractory metal spaced from said body;

B. placing said joining surfaces of said members in contact with a brazing alloy comprising on a weight basis about 80-89 percent copper, about 5-15 percent silver, and about 4-6 percent phosphorus;

C. heating the brazing alloy at least to its wetting point for a period of time sufficient to melt the brazing alloy; and

D. allowing the molten brazing alloy to cool and solidify in contact with said joining surfaces of said members, thereby to join said contact member and said lead member into a unitary structure.

2. The process of claim 1 including the additional step of subsequently applying and fusing a passivating layer of a passivating material about said body and about said contact member between said joining surface thereof and said body.

3. The process of claim 1 wherein the refractory metal is selected from the group consisting of tungsten, molybdenum, tantalum, and alloys thereof.

4. The process of claim 3 wherein said refractory metal is molybdenum.

5. The process of claim 1 wherein the conductive metal is selected from the group consisting of silver and copper and alloys thereof.

6. The process of claim 5 wherein said conductive metal is copper.

7. The process of claim 2 wherein the passivating material is selected from the group consisting of glass and plastic.

8. The process of claim 7 wherein the passivating material is glass.

9. The process of claim 1 wherein said semiconductor body is formed substantially of silicon.

10. The process of claim 2 wherein said refractory metal is molybdenum, said conductive metal is copper, said passivating material is glass, and said semiconductor body is formed substantially of silicon.

11. The process of claim 1 wherein the heating of step (C) is performed in an inert atmosphere.

12. The process of claim 1 wherein said joining surfaces of said members are of substantially the same configuration and size, and wherein the brazing alloy is provided as a preform with joining surfaces of substantially similar configuration and size abutting said joining surfaces of said members.

13. The process according to claim 2 wherein said refractory metal is selected from the group consisting of tungsten, molybdenum, tantalum, and alloys thereof;

said thermally and electrically conductive metal is selected from the group consisting of silver, copper and alloys thereof;

said brazing alloy comprises on a weight basis about 80 percent copper, about 15 percent silver and about 5 percent phosphorus; and

said passivating material is selected from the group consisting of glass and plastic.

14. A process for attaching a lead member to a semiconductor body comprises the steps of

A. providing (i) a semiconductor body having a joining surface;

(ii) a contact member formed substantially of a refractory metal and having a joining surface of said refractory metal at each end thereof;

(iii) a lead member formed substantially of a thermally and electrically conductive metal and having at one end a joining surface; and

(iv) a brazing preform formed substantially of a brazing alloy comprising on a weight basis about 80-89 percent copper, about 5-15 percent silver, and about 4-6 percent phosphorus, and having a joining surface at each end thereof.

B. forming an assembly by simultaneously contacting (i) said joining surface of said semiconductor body to one of said refractory metal joining surfaces of said contact member;

(ii) the other of said refractory metal joining surfaces of said contact member to one of said brazing alloy joining surfaces of said preform; and

(iii) the other of said brazing alloy joining surfaces of said preform to said conductive metal joining surface of said lead member;

C. heating said assembly in an inert atmosphere at least to the alloy wetting point to cause brazing of contacting joining surfaces; and

D. allowing said assembly to cool, thereby to join said semiconductor body, said contact member, said preform, and said lead member into a unitary structure.

15. The process of claim 14 wherein said refractory metal is selected from the group consisting of molybdenum, tungsten, tantalum and alloys thereof.

16. The process of claim 15 wherein said refractory metal is molybdenum.

17. The process of claim 14 wherein said conductive metal is selected from the group consisting of copper and silver and alloys thereof.

18. The process of claim 17 wherein said conductive metal is copper.

19. The process of claim 14 wherein said semiconductor body is formed substantially of silicon and has an electrically conductive layer of metal selected from the group consisting of aluminum and gold disposed thereon to define said joining surface thereof.

20. The process of claim 14 wherein said refractory metal is molybdenum, said conductive metal is copper, and said semiconductor body is formed substantially of silicon with a layer of aluminum disposed thereon to define said joining surface thereof.

21. The process of claim 14 including the additional step of subsequently applying and fusing a passivating layer of a passivating material about said semiconductor body and about said contact member between said refractory metal joining surfaces.

22. The process of claim 21 wherein said passivating material is selected from the group consisting of glass and plastic.

23. The process of claim 22 wherein said passivating material is glass.

24. The process of claim 21 wherein said refractory material is molybdenum, said conductive metal is copper, said passivating material is glass, and said semiconductor body is formed substantially of silicon and has an electrically conductive layer of aluminum disposed thereon to define said joining surface thereof.

25. The process according to claim 14 wherein said semiconductor body is formed substantially of silicon and has an electrically conductive layer of a metal selected from the group consisting of aluminum and gold disposed thereon to define said joining surface thereof;

said refractory metal is selected from the group consisting of molybdenum, tungsten, tantalum, and alloys thereof;

said thermally and electrically conductive metal is selected from the group consisting of copper, silver and alloys thereof; and

said brazing alloy comprises on a weight basis about 80 percent copper, about 15 percent silver, and about 5 percent phosphorus.

26. The process of claim 25 including the additional step of subsequently applying and fusing a passivating layer of a passivating material selected from the group consisting of glass and plastic about said semiconductor body and about said contact member between said refractory joining surfaces.

27. The process of claim 14 wherein said assembly is heated in an inert atmosphere at substantially atmospheric pressure.