BONDING SYSTEM FOR SEMICONDUCTOR DEVICE

• US 3,593,412 A
• Filed: 07/22/1969
• Issued: 07/20/1971
• Est. Priority Date: 07/22/1969
• Status: Expired due to Term

• Current Assignee: Robert S. Foote
• Original Assignee: Robert S. Foote
• Inventors: Foote, Robert S.
• Application Number:
  US04/843,717
• Time in Patent Office: 728 Days
• US Class Current: 228/123.1
• 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 2224/8383 Solid-solid interdiffusion
• CPC Class Codes: H01L 24/29 of an individual layer connector
• CPC Class Codes: H01L 24/31 Structure, shape, material or disposition of the layer connectors after the connecting process
• CPC Class Codes: H01L 24/83 using a layer connector
• CPC Class Codes: H01L 2924/01005 Boron [B]
• CPC Class Codes: H01L 2924/01006 Carbon [C]
• CPC Class Codes: H01L 2924/01026 Iron [Fe]
• CPC Class Codes: H01L 2924/01027 Cobalt [Co]
• CPC Class Codes: H01L 2924/01028 Nickel [Ni]
• CPC Class Codes: H01L 2924/01033 Arsenic [As]
• CPC Class Codes: H01L 2924/01047 Silver [Ag]
• CPC Class Codes: H01L 2924/01078 Platinum [Pt]
• CPC Class Codes: H01L 2924/01079 Gold [Au]
• CPC Class Codes: H01L 2924/0132 Binary Alloys
• CPC Class Codes: H01L 2924/0133 Ternary Alloys
• CPC Class Codes: H01L 2924/014 Solder alloys

Abstract

A method of bonding a semiconductor device to a metal substrate involving depositing a gold solder preform onto the device and coating the metal substrate with a first layer of gold, a second layer of silver and a third layer of gold. The device is bonded to the metal substrate by heating the substrate to an elevated temperature and placing the gold preform on top of the third gold layer of the substrate.

Claims

2. The method as described in claim 1 wherein said gold solder preform has a thickness of about 100 to 400 mils.

3. The method as described in claim 1 wherein said first layer of gold has a thickness of about 0.5 to 3 microinches.

4. A method as described in claim 1 wherein said first and said second layer of gold and said layer of silver have a combined thickness of about 21 to 50 microinches.

5. A method as described in claim 1 wherein said heating step is between about 425* C. and 475* C.

6. The method of bonding a semiconductor device onto a header comprising the steps of:

coating a surface of said semiconductor device with a first layer of gold, depositing a gold solder preform on said first layer of gold, coating a portion of said header with a first layer of gold, coating said first gold layer with a layer of silver about 8 to10 microinches thick, coating said silver layer with a second layer of gold about 12 to 50 microinches thick, placing said semiconductor device on said header whereby said gold preform is in contact with said second gold layer, and heating said header to a temperature sufficient to bond said header to said device.