Fine wire of gold alloy, method for manufacture thereof and use thereof

• US 6,103,025 A
• Filed: 07/06/1998
• Issued: 08/15/2000
• Est. Priority Date: 07/07/1997
• Status: Expired due to Term

• Current Assignee: Heraeus Deutschland GmbH & Co. KG (Heraeus Holding GMBH)
• Original Assignee: Heraeus Holding GMBH
• Inventors: Schrapler, Lutz, Reuel, Jurgen, Herklotz, Gunther, Simons, Christoph
• Primary Examiner(s): SHEEHAN, JOHN P
• Application Number:
  US09/110,905
• Time in Patent Office: 771 Days
• Field of Search: 148/430, 148/678, 420/508, 420/509, 420/510
• US Class Current: 148/430
• CPC Class Codes: C22C 5/02 Alloys based on gold
• CPC Class Codes: H01L 2224/13 of an individual bump connector
• CPC Class Codes: H01L 2224/13099 Material
• CPC Class Codes: H01L 2224/4321 Pulling
• CPC Class Codes: H01L 2224/45015 being circular
• CPC Class Codes: H01L 2224/45144 Gold (Au) as principal constituent
• CPC Class Codes: H01L 2224/48 of an individual wire connector
• CPC Class Codes: H01L 24/10 Bump connectors bumps on insulating substrates, e.g. chip carriers, H01L23/49816; Manufacturing methods related thereto
• CPC Class Codes: H01L 24/13 of an individual bump connector
• CPC Class Codes: H01L 24/43 Manufacturing methods
• CPC Class Codes: H01L 24/45 of an individual wire 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 2924/00014 the subject-matter covered by the group, the symbol of which is combined with the symbol of this group, being disclosed without further technical details
• CPC Class Codes: H01L 2924/01004 Beryllium [Be]
• CPC Class Codes: H01L 2924/01006 Carbon [C]
• CPC Class Codes: H01L 2924/01012 Magnesium [Mg]
• CPC Class Codes: H01L 2924/01013 Aluminum [Al]
• CPC Class Codes: H01L 2924/01014 Silicon [Si]
• CPC Class Codes: H01L 2924/01015 Phosphorus [P]
• CPC Class Codes: H01L 2924/01018 Argon [Ar]
• CPC Class Codes: H01L 2924/0102 : Calcium [Ca]
• CPC Class Codes: H01L 2924/01021 : Scandium [Sc]
• CPC Class Codes: H01L 2924/01022 : Titanium [Ti]
• CPC Class Codes: H01L 2924/01023 : Vanadium [V]
• CPC Class Codes: H01L 2924/01027 : Cobalt [Co]
• CPC Class Codes: H01L 2924/01028 : Nickel [Ni]
• CPC Class Codes: H01L 2924/01031 : Gallium [Ga]
• CPC Class Codes: H01L 2924/01032 : Germanium [Ge]
• CPC Class Codes: H01L 2924/01038 : Strontium [Sr]
• CPC Class Codes: H01L 2924/01039 : Yttrium [Y]
• CPC Class Codes: H01L 2924/01044 : Ruthenium [Ru]
• CPC Class Codes: H01L 2924/01045 : Rhodium [Rh]
• CPC Class Codes: H01L 2924/01046 : Palladium [Pd]
• CPC Class Codes: H01L 2924/01047 : Silver [Ag]
• CPC Class Codes: H01L 2924/01049 : Indium [In]
• CPC Class Codes: H01L 2924/0105 : Tin [Sn]
• CPC Class Codes: H01L 2924/01056 : Barium [Ba]
• CPC Class Codes: H01L 2924/01057 : Lanthanum [La]
• CPC Class Codes: H01L 2924/01058 : Cerium [Ce]
• CPC Class Codes: H01L 2924/01059 : Praseodymium [Pr]
• CPC Class Codes: H01L 2924/0106 : Neodymium [Nd]
• CPC Class Codes: H01L 2924/01063 : Europium [Eu]
• CPC Class Codes: H01L 2924/01066 : Dysprosium [Dy]
• CPC Class Codes: H01L 2924/01068 : Erbium [Er]
• CPC Class Codes: H01L 2924/01076 : Osmium [Os]
• CPC Class Codes: H01L 2924/01077 : Iridium [Ir]
• CPC Class Codes: H01L 2924/01078 : Platinum [Pt]
• CPC Class Codes: H01L 2924/01079 : Gold [Au]
• CPC Class Codes: H01L 2924/01105 : Rare earth metals
• CPC Class Codes: H01L 2924/01202 : 2N purity grades, i.e. 99%
• CPC Class Codes: H01L 2924/013 : Alloys
• CPC Class Codes: H01L 2924/014 : Solder alloys
• CPC Class Codes: H01L 2924/14 : Integrated circuits
• CPC Class Codes: H01L 2924/181 : Encapsulation
• CPC Class Codes: H01L 2924/19043 : being a resistor
• CPC Class Codes: H01L 2924/20752 : larger or equal to 20 microns less than 30 microns
• CPC Class Codes: H01L 2924/3025 : Electromagnetic shielding

Abstract

Fine wires of a gold alloy of 0.05 to 0.95 wt % platinum, palladium or a mixture thereof; 0.001 to 0.1 wt % mischmetal containing at least 50 wt. % of cerium; and 0 to 0.1 wt % of alkaline earth metal. The wire has a favorable strength-to-elongation ratio and is suitable both for wire bonding and for making the ball bumps of flip chips.

Claims

1. A fine wire of a gold alloy containing mischmetal, for bonding semiconductor devices, wherein the gold alloy comprises a total of 0.05 to 0.95 wt % of platinum or palladium or a mixture thereof;

0.001 to 0.1 wt % of mischmetal containing at least 50 wt. % of cerium;

0 to 0.1 wt % of alkaline earth metal; and

the remainder being gold.

2. A fine wire according to claim 1, wherein the total platinum or palladium or mixture thereof content of the gold alloy is 0.25 to 0.9 wt %.

3. A fine wire according to claim 1, wherein the mischmetal content of the gold alloy is 0.001 to 0.01 wt %.

4. A fine wire according to claim 1, wherein the alkaline earth metal content of the gold alloy is 0.0001 to 0.01 wt %.

5. A fine wire according to claim 1, wherein the gold alloy contains platinum.

6. A fine wire according to claim 1, wherein the gold alloy contains palladium.

7. A fine wire according to claim 1, wherein

the platinum or palladium, or mixture thereof content of the gold alloy is 0.25 to 0.9 wt %;

the mischmetal content of the gold alloy is 0.001 to 0.01 wt %; and

the alkaline earth metal content of the gold alloy is 0.0001 to 0.01 wt %.

8. A fine wire of a gold alloy containing mischmetal, for bonding semiconductor devices, wherein the gold alloy comprises a total of 0.05 to 0.95 wt % of platinum or palladium or a mixture thereof;

0.001 to 0.1 wt % of mischmetal containing at least 50 wt. % of cerium;

0 to 0.1 wt % of alkaline earth metal; and

the remainder being gold, and wherein the alkaline earth metal is a mixture of beryllium and calcium.

9. A method for making a fine wire from a gold alloy containing mischmetal for bonding to a semiconductor comprising melting a gold alloy of 0.05 to 0.95 wt % of platinum or palladium or a mixture thereof, 0.001 to 0.1 wt % of mischmetal containing at least 50 wt. % cerium, 0 to 0.1 wt % of alkaline earth metal and the remainder being gold, continuously casting the melted alloy into a strand, drawing the strand to a wire for bonding to a semiconductor, and annealing the wire.

10. A method according to claim 9, wherein the melted alloy is continuously cast as a strand of circular cross section.

11. A method according to claim 9, wherein the gold alloy having a platinum or palladium or mixture thereof content of 0.25 to 0.9 wt % is melted.

12. A method according claim 9, wherein the gold alloy having a mischmetal content of 0.001 to 0.01 wt % is melted.

13. A method according to claim 9, wherein the gold alloy having an alkaline earth metal content of 0.0001 to 0.01 wt % is melted.

14. A method according to claim 9, wherein the gold alloy containing a mixture of beryllium and calcium as alkaline earth metal is melted.

15. A method according to claim 9, wherein the gold alloy containing platinum is melted.

16. A method according to claim 9, wherein the gold alloy containing palladium is melted.

17. A method according to claim 9, wherein the annealing step comprises annealing the wire at 300 to 700°

C.