Ceramic package type semiconductor device and method of assembling the same

• US 5,081,067 A
• Filed: 05/10/1991
• Issued: 01/14/1992
• Est. Priority Date: 02/10/1989
• Status: Expired due to Term

• Current Assignee: Fujitsu Microelectronics Limited (Fujitsu Limited)
• Original Assignee: Fujitsu Limited
• Inventors: Sugimoto, Masahiro, Shimizu, Nobutaka, Harada, Shigeki, Tsujimura, Takehisa
• Primary Examiner(s): Hearn, Brian E.
• Assistant Examiner(s): Picardat, Kevin M.
• Application Number:
  US07/698,030
• Time in Patent Office: 249 Days
• Field of Search: 437/209, 437/218, 437/217, 437/216, 437/215, 357/80, 357/81, 357/74, 361/381
• US Class Current: 228/123.1
• CPC Class Codes: H01L 23/04 characterised by the shape of the container or parts, e.g. caps, walls
• CPC Class Codes: H01L 23/057 the leads being parallel to the base
• CPC Class Codes: H01L 23/367 Cooling facilitated by shape of device H01L23/38, H01L23/40, H01L23/42, H01L23/44, H01L23/46 take precedence
• CPC Class Codes: H01L 23/49827 Via connections through the substrates, e.g. pins going through the substrate, coaxial cables H01L23/49822, H01L23/49833, H01L23/4985, H01L23/49861 take precedence
• 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 2924/0002 Not covered by any one of groups H01L24/00, H01L24/00 and H01L2224/00
• CPC Class Codes: H01L 2924/01079 Gold [Au]
• CPC Class Codes: H01L 2924/15312 being a pin array, e.g. PGA
• CPC Class Codes: Y10T 29/49144 by metal fusion

Abstract

A ceramic package type semiconductor device comprising: a ceramic substrate having a wiring pattern layer formed on a top surface thereof; at least one semiconductor element mounted on the ceramic substrate with a top face thereof facing downward and electrically connected to the wiring patttern layer; a metal cap having at least one through-hole corresponding to an external size of the semiconductor element and an end portion thereof soldered to the top surface of the ceramic substrate, so that a top surface of the metal cap and a bottom surface of the semiconductor element fitting into the through-hole form a flat plane: and a heatsink member comprising a plate portion which is soldered to the flat plane of the metal cap and the semiconductor element to complete a hermetic sealing of the semiconductor element.

Claims

1. A method of assembling a semiconductor device of a hermetic sealing ceramic package type comprising the steps of:

mounting at least one semiconductor element on a ceramic substrate with a top face thereof facing downward and electrically connected to a wiring pattern layer of the ceramic substrate;

placing a solder frame on said ceramic substrate at a peripheral region of the substrate;

placing a metal cap having at least one through-hole corresponding to an external size of said semiconductor element, on said solder frame, to fit said semiconductor element into said through-hole and to form a flat plane with the top surface of said metal cap and the bottom surface of said semiconductor element;

heating the assembling device to solder said metal cap to said ceramic substrate;

placing a solder plate on said flat plane of the top surface of said metal cap and the bottom surface of said semiconductor element;

placing a plate portion of a heatsink member on said solder plate; and

heating the assembling device to solder said plate portion to said metal cap and said semiconductor element, whereby a hermetic sealing of the semiconductor element is completed.

2. A method according to claim 1, wherein said solder frame has a melting point higher than that of said solder plate, and said heating step for said solder plate is carried out at a temperature higher than that of said heating step for said solder frame.

3. A method according to claim 2, wherein said solder frame is made of Au-Sn solder, and said solder plate is made of Pb-Sn solder.

4. A method according to claim 1, wherein said heatsink plate portion is made of a material selected from a group consisting of aluminum nitride ceramic, silicon carbide ceramic, Cu-W alloy, Cu-Mo alloy and AlSi alloy, and is coated with a metal layer for soldering.

5. A method according to claim 4, wherein said heatsink plate portion of aluminum nitride ceramic is coated with a metal lower layer formed by one of a sputtering method and a screen-printing method, and a metal upper layer is formed on the lower layer by a plating method.

6. A method according to claim 5, wherein said plating metal layer consists of a Ni plating layer having a thickness of 1.0 μ

m or more and an Au plating layer having a thickness of 0.2 to 1.0 μ

m and formed on the Ni plating layer.

7. A method according to claim 1, wherein said metal cap is made of an alloy selected from a group consisting of Fe-Ni-Co alloy and Fe-Ni alloy and is coated with a metal layer for soldering.

8. A method according to claim 7, wherein said metal cap is coated with a Ni plating layer having a thickness of 2.0 μ

m or more and then an Au plating layer having a thickness of 0.1 to 1.0 μ

m.

9. A method according to claim 1 further comprising, after said heating step for said solder plate, a step of bonding a heat dissipation fin portion to said heatsink plate portion with a resin.

10. A method according to claim 1, wherein said heatsink member consists of the plate portion and a heat dissipation fin portion fixed to said plate portion.

11. A method according to claim 10, wherein said fin portion is fixed to said plate portion with a solder.

12. A method according to claim 10, wherein said fin portion is fixed to said plate portion by a friction welding method.

13. A method of assembling a semiconductor device of a hermetic sealing ceramic package type comprising the steps of:

mounting at least one semiconductor element on a ceramic substrate with a top face thereof facing downward and electrically connected to a wiring pattern layer of the ceramic substrate;

placing a solder frame on said ceramic substrate at a peripheral region of the substrate;

placing a metal cap having at least one through-hole corresponding to an external size of said semiconductor element, on said solder frame, to fit said semiconductor element into said through-hole and to form a flat plane with the top surface of said metal cap and the bottom surface of said semiconductor element;

placing a solder plate made of the same solder as that of said solder frame on said flat plane of the top surface of said metal cap and the bottom surface of said semiconductor element;

placing a plate portion of a heatsink member on said solder plate; and

heating the assembling device to solder said metal cap to said ceramic substrate and to simultaneously solder said plate portion to said metal cap and said semiconductor element, whereby a hermetic sealing of the semiconductor element is completed.

14. A method according to claim 13, wherein said heatsink plate portion is made of a material selected from a group consisting of aluminum nitride ceramic, silicon carbide ceramic, Cu-W alloy, Cu-Mo alloy, Cu, Al and Mo and is coated with metal layer for soldering.

15. A method according to claim 14, wherein said heatsink plate portion of aluminum nitride ceramic is coated with a metal lower layer formed by one of a sputtering method and a screen-printing and baking method, and a metal upper layer is formed on the lower layer by a plating method.

16. A method according to claim 15, wherein said plating metal layer consists of a Ni plating layer having a thickness of 1.0 μ

m or more and an Au plating layer having a thickness of 0.2 to 1.0 μ

m and formed on the Ni plating layer.

17. A method according to claim 13, wherein said metal cap is made of an alloy selected from a group consisting of Fe-Ni-Co alloy and Fe-Ni alloy and is coated with a metal layer for soldering.

18. A method according to claim 17, wherein said metal cap is coated with a Ni plating layer having a thickness of 2.0 μ

m or more and then an Au plating layer having a thickness of 0.1 to 1.0 μ

m.

19. A method according to claim 13 further comprising, after said heating step for said solder plate, a step of bonding a heat dissipation fin portion to said heatsink plate portion with a resin.

20. A method according to claim 13, wherein said heatsink member consists of the plate portion and a heat dissipation fin portion fixed to said plate portion.

21. A method according to claim 20, wherein said fin portion is fixed to said plate portion with a solder.

22. A method according to claim 20, wherein said fin portion is fixed to said plate portion by a friction welding method.