Circuit board assembly and method of attaching a chip to a circuit board

• US 20050151215A1
• Filed: 01/13/2004
• Published: 07/14/2005
• Est. Priority Date: 01/13/2004
• Status: Active Grant

• Current Assignee: Raytheon Company (Rtx Corporation)
• Original Assignee: Raytheon Company (Rtx Corporation)
• Inventors: Quan, Clifton, Rolston, Kevin C., Hauhe, Mark S., Wong, Tse E., Fenger, Harold S.
• Granted Patent: US 7,298,235 B2
• Time in Patent Office: Days
• US Class Current: 257/421
• CPC Class Codes: H01L 2224/73204 the bump connector being embedded into the 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 2924/07811 Extrinsic, i.e. with electrical conductive fillers
• CPC Class Codes: H01L 2924/1305 Bipolar Junction Transistor [BJT]
• CPC Class Codes: H01Q 21/0025 Modular arrays
• CPC Class Codes: H01Q 21/0087 Apparatus or processes specially adapted for manufacturing antenna arrays manufacturing waveguides H01P11/00

Abstract

An antenna array is assembled by direct attaching a flip chip transmit/receive (T/R) module to an antenna circuit board. A fillet bond is applied to the circuit board and the flip chip T/R module around at least a portion of the periphery of the flip chip T/R module.

Claims

1. A method of assembling an antenna array, comprising:

direct attaching a flip chip transmit/receive (T/R) module to an antenna circuit board;

applying a fillet bond to the circuit board and the chip around at least a portion of a periphery of the flip chip T/R module.

2. The method of claim 1, wherein the antenna circuit board is a multi-layered flexible circuit board.

3. The method of claim 1, wherein direct attaching the flip chip T/R module comprises at least making R/F connections, DC power connections and digital connections.

4. The method of claim 1, wherein said attaching a flip chip T/R module comprises attaching the flip chip T/R module without applying the fillet bond over R/F traces on the circuit board.

5. The method of claim 4, wherein the T/R module operates at frequencies greater than about 6 GHz.

6. The method of claim 1, wherein the fillet bond extends around an entire periphery of the flip chip T/R module.

7. The method of claim 6, wherein the T/R module operates at frequencies less than about 6 GHz.

8. The method of claim 6, further comprising underfilling the flip chip T/R module.

9. The method of claim 1, wherein direct attaching the flip chip T/R module to the circuit board comprises connecting bumps on the flip chip T/R module to corresponding contact pads on the circuit board with a conductive medium.

10. The method of claim 9, wherein the conductive medium comprises at least one of electrically conductive adhesive or solder.

11. The method of claim 9, wherein the conductive medium comprises an anisotropically conductive film.

12. The method of claim 9, wherein said direct attaching comprises creating one of a pressure or thermosonic contact.

13. A method of assembling an antenna array, comprising:

providing a multi-layered flexible antenna array circuit board having RF circuit traces formed on a surface thereof;

direct attaching a T/R module to the circuit board;

applying a fillet bond to the circuit board and flip chip T/R module, the fillet bond extending around at least a portion of a periphery of the flip chip T/R module, without applying the fillet bond over said RF traces.

14. The method of claim 13, wherein direct attaching the T/R module to the circuit board comprises connecting bumps on the T/R module to contact pads on the circuit board with a conductive medium.

15. The method of claim 13, wherein the T/R module operates at frequencies greater than 6 Ghz.

16. A method of assembling an antenna array, comprising:

providing a multi-layered flexible antenna array circuit board;

direct attaching a flip chip T/R module to the circuit board;

applying a fillet bond to the circuit board and chip around the periphery of the T/R module.

17. The method of claim 16, further comprising underfilling the T/R module with underfill.

18. The method of claim 17, wherein the underfill comprises epoxy.

19. An assembly comprising:

a chip;

a flip chip connection connecting the chip to a circuit board, wherein the flip chip connection comprises at least an RF connection, a DC power connection and a digital connection.

20. The assembly of claim 19, wherein the chip is a T/R module.

21. The assembly of claim 19, wherein the circuit board comprises a multi-layer flexible antenna circuit board.

22. The assembly of claim 19, further comprising:

a fillet bond connected to the circuit board and the chip around at least a portion of the chip.

23. The assembly of claim 22, wherein the circuit board comprises RF traces and the fillet bond does not cover any portion of any of the RF traces.

24. The assembly of claim 23, wherein the chip is a T/R module which operates at frequencies greater than 6 Ghz.

25. The assembly of claim 19, further comprising:

underfill between at least a portion of the chip and the circuit board.

27. An circuit comprising:

a plurality of contact pads;

a transmit/receive chip comprising a plurality of connection portions for connecting with corresponding contact pads of the plurality of contact pads;

a conductive medium making RF, digital and DC power connections between at least some of the plurality of connection portions and respective, corresponding contact pads.

26. The assembly of claim 32, wherein the underfill comprises epoxy.

28. The circuit according to claim 27, wherein the conductive medium comprises one of Electrically conductive adhesive or solder.

29. The circuit according to claim 27, wherein the conductive medium comprises an anisotropically conductive film.

30. The circuit according to claim 27, wherein at least one of the plurality of connection portions is connected to a corresponding at least one of the plurality of contact pads by one of a pressure or thermosonic contact.

31. The circuit according to claim 27, further comprising an epoxy underfill between the chip and the circuit board.

32. The circuit according to claim 27, further comprising:

a fillet bond between the circuit board and the chip around at least a portion of the chip.

33. The circuit according to claim 32, wherein the fillet bond comprises non-conductive adhesive.

34. The circuit according to claim 33, wherein the non-conductive adhesive has a high viscosity.

35. The circuit according to claim 32, wherein the fillet bond has a high modulus.

36. The circuit according to claim 32, wherein the bond extends up an edge of the chip between 50% and 100% of a thickness of the edge of the chip.

37. The circuit according to claim 32, wherein the fillet bond is not applied over RF or microwave traces on the board.

38. The circuit according to claim 37, wherein the chip is a high frequency T/R module.

39. The circuit according to claim 32, wherein the fillet bond extends around the perimeter of the chip.

40. The circuit according to claim 39, further comprising an epoxy underfill.