ACF attachment for radiation detector

• US 8,071,953 B2
• Filed: 04/29/2008
• Issued: 12/06/2011
• Est. Priority Date: 04/29/2008
• Status: Active Grant

• Current Assignee: Redlen Technologies, Inc. (Canon Inc.)
• Original Assignee: Redlen Technologies, Inc. (Canon Inc.)
• Inventors: Lu, Pinghe, Chen, Henry, Bindley, Glenn
• Primary Examiner(s): Porta, David
• Assistant Examiner(s): BOOSALIS, FANI POLYZOS
• Application Number:
  US12/111,413
• Publication Number:
  US 20090321651A1
• Time in Patent Office: 1,316 Days
• Field of Search: 250/370.09, 250/370.13, 257/428
• US Class Current: 250/370.13
• CPC Class Codes: G01T 1/00 Measuring X-radiation, gamma radiation, corpuscular radiation, or cosmic radiation G01T3/00, G01T5/00 take precedence
• CPC Class Codes: G01T 1/24 with semiconductor detectors
• CPC Class Codes: H01L 27/14661 of the hybrid type
• CPC Class Codes: H01L 27/1469 Assemblies, i.e. hybrid integration
• CPC Class Codes: H01L 31/115 Devices sensitive to very short wavelength, e.g. X-rays, gamma-rays or corpuscular radiation
• CPC Class Codes: H05K 3/323 by applying an anisotropic conductive adhesive layer over an array of pads
• CPC Class Codes: Y10S 977/762 Nanowire or quantum wire, i.e. axially elongated structure having two dimensions of 100 nm or less
• CPC Class Codes: Y10T 156/10 Methods of surface bonding and/or assembly therefor

Abstract

A device includes (a) radiation detector including a semiconductor substrate having opposing front and rear surfaces, a cathode electrode located on the front surface of said semiconductor substrate, and a plurality of anode electrodes on the rear surface of said semiconductor substrate, (b) a printed circuit board, and (c) an electrically conductive polymeric film disposed between circuit board and the anode electrodes. The polymeric film contains electrically conductive wires. The film bonds and electrically connects the printed circuit board and anode electrodes.

Claims

1. A device, comprising:

a radiation detector comprising;

a semiconductor substrate having opposing front and rear surfaces;

a cathode electrode located on the front surface of said semiconductor substrate; and

a plurality of anode electrodes on the rear surface of said semiconductor substrate;

a printed circuit board; and

a polymeric film disposed between the printed circuit board and the anode electrodes, wherein the polymeric film comprises electrically conductive wires electrically connecting the radiation detector with the printed circuit board.

2. The device of claim 1, wherein the polymeric film is an anisotropic conductive film.

3. The device of claim 2, wherein the anisotropic conductive film comprises a thermoplastic polymer or an epoxy matrix in which the wires are located.

4. The device of claim 2, further comprising an edge coating covering bonding lines of the anisotropic conductive film.

5. The device of claim 4, wherein the edge coating comprises a UV curable epoxy, solder mask or silicone.

6. The device of claim 2, wherein the electrically conductive wires render the polymeric film an anisotropic conductive film.

7. The device of claim 1, wherein:

the semiconductor substrate comprises a CdTe or a CZT substrate; and

the polymeric film bonds to both the printed circuit board and to the anode electrodes at a temperature of about 135°

C. or less and at a pressure of about 35 psi or less.

8. The device of claim 1, wherein the polymeric film which comprises electrically conductive wires contacts the anode electrodes.

9. A device, comprising:

a radiation detector comprising;

a semiconductor substrate having opposing front and rear surfaces;

a cathode electrode located on the front surface of said semiconductor substrate; and

a plurality of anode electrodes on the rear surface of said semiconductor substrate;

a printed circuit board; and

a polymeric film disposed between the printed circuit board and the anode electrodes, wherein the polymeric film comprises electrically conductive wires electrically connecting the radiation detector with the printed circuit board, wherein the polymeric film is an anisotropic conductive film, and wherein the wires are metallic nanowires.

10. The device of claim 9, wherein the anisotropic conductive film comprises up to about 20 million nanowires per square inch.

11. The device of claim 9, wherein the nanowires comprise NiO coated Ni nanowires.

12. A method of electrically connecting a radiation detector to a printed circuit board, comprising:

providing a radiation detector comprising;

a semiconductor substrate having opposing front and rear surfaces;

a cathode electrode located on the front surface of said semiconductor substrate; and

a plurality of anode electrodes on the rear surface of said semiconductor substrate;

providing a printed circuit board;

providing an electrically conductive polymeric film comprising electrically conductive wires in a polymer matrix between the printed circuit board and the plurality of anodes; and

bonding the radiation detector to the printed circuit board using at least one of a bonding temperature of 135°

C. or less or a compressive force of about 35 psi or less.

13. The method of claim 12, wherein the step of bonding is conducted at the temperature of 135°

C. or less.

14. The method of claim 12, wherein the step of bonding is conducted at the compressive force of about 35 psi or less.

15. The method of claim 12, wherein the step of bonding is conducted at the bonding temperature of 135°

C. or less and the compressive force of about 35 psi or less.

16. The method of claim 15, wherein the step of bonding is conducted at the bonding temperature of about 125°

C. to about 130°

C. and the compressive force of about 25 psi to about 35 psi.

17. The method of claim 15, wherein the electrically conductive wires electrically connect the anode electrodes to the printed circuit board.

18. The method of claim 17, wherein the electrically conductive polymeric film is an anisotropic conductive film which comprises a thermoplastic polymer or an epoxy matrix in which the wires are located.

19. The method of claim 18, wherein the electrically conductive wires render the polymeric film an anisotropic conductive film.

20. The method of claim 17, further comprising applying an edge coating over bonding lines of the anisotropic conductive film.

21. The method of claim 20, wherein the edge coating comprises a UV curable epoxy, solder mask or silicone.

22. The method of claim 12, wherein the semiconductor substrate comprises a CdTe or a CZT substrate.

23. The method of claim 12, further comprising annealing the detector after the step of bonding to reduce a leakage current of the detector.

24. The method of claim 12, wherein the electrically conductive polymeric film contacts the printed circuit board and the plurality of anodes.

25. A method of electrically connecting a radiation detector to a printed circuit board, comprising:

providing a radiation detector comprising;

a semiconductor substrate having opposing front and rear surfaces;

a cathode electrode located on the front surface of said semiconductor substrate; and

a plurality of anode electrodes on the rear surface of said semiconductor substrate;

providing a printed circuit board;

providing an electrically conductive polymeric film comprising electrically conductive wires in a polymer matrix between the printed circuit board and the plurality of anodes; and

bonding the radiation detector to the printed circuit board using a bonding temperature of 135°

C. or less and a compressive force of about 35 psi or less,

wherein the electrically conductive wires electrically connect the anode electrodes to the printed circuit board, and

wherein the wires are metallic nanowires.

26. The method of claim 25, wherein the nanowires comprise NiO coated Ni nanowires.