Radiation imaging device and system

• US 20030155516A1
• Filed: 05/23/2002
• Published: 08/21/2003
• Est. Priority Date: 02/15/2002
• Status: Active Grant

• Current Assignee: AJAT OY Limited
• Original Assignee: AJAT OY Limited
• Inventors: Spartiotis, Konstantinos, Puhakka, Kimmo Petteri
• Granted Patent: US 7,189,971 B2
• Time in Patent Office: Days
• US Class Current: 250/370.09
• CPC Class Codes: G01T 1/2928 using solid state detectors
• CPC Class Codes: H01L 27/14658 X-ray, gamma-ray or corpuscular radiation imagers measuring X-, gamma- or corpuscular radiation G01T1/00
• CPC Class Codes: H01L 27/14661 of the hybrid type

Abstract

An x-ray and gamma-ray radiation energy imaging device has its semiconductor detector substrate and semiconductor readout/processing substrate both mounted on opposite sides of, and electrically communicating through, an intermediate substrate. The substrates are all substantially planar with the top plan perimeter of the semiconductor readout/processing substrate falling within the top plan shadow perimeter of the corresponding semiconductor detector substrate with which it electrically communicates. Additionally, all of the readout/processing circuitry contacts of the semiconductor readout/processing substrate are disposed on the surface of the semiconductor readout/processing substrate that electrically communicates with the intermediate substrate. Substantially all electrical communication to and from the semiconductor readout/processing substrate is routed through the intermediate substrate. The intermediate substrate is a printed circuit board or similar construct. The electrical contacts between the semiconductor substrates and the intermediate substrate are accomplished using bump-bonds, conductive adhesive bonds, conductive adhesive films or a combination thereof. One or two dimensional planar arrays of semiconductor readout/processing substrates and corresponding semiconductor detector substrates can be mounted on a single intermediate substrate using “tiling” techniques known in the art to form a mosaic radiation imaging device of increased active imaging area and reduced/minimized imaging dead area.

Claims

1. An x-ray and gamma-ray radiation energy imaging device comprising:

a detector substrate, the detector substrate having an electrode surface and a pixel surface, and disposed to convert said radiation energy impinging on the electrode surface to electrical charges, with the electrode surface having a continuous contact electrode disposed thereon, and with the pixel surface having a plurality of pixel collector electrodes and associated pixel contacts thereon with the pixel collector electrodes for collecting the electrical charges and the pixel contacts disposed in a pixel contact pattern;

an ASIC readout substrate comprising a plurality of pixel circuits and having a readout surface disposed opposite the pixel surface of the detector substrate, the pixel circuits each having an electrical transmission contact processed on the readout surface in a transmission contact pattern, the transmission contacts being inputs to pixel circuits of the ASIC readout substrate, and a plurality of electrical I/O contacts processed on the readout surface in an I/O contact pattern, the I/O contacts being the input and output electrical contacts for the ASIC readout substrate;

an intermediate substrate disposed between the detector substrate and the ASIC readout substrate, and having an entry face adjacent the pixel surface and an exit face adjacent the readout surface, a plurality of discrete conductive via passages, the passages having a first end at the entry face disposed in an entry passage pattern corresponding to the pixel pattern and a second end at the exit face disposed in an exit passage pattern corresponding to the transmission contact pattern, and a plurality of wire contacts on the exit face disposed in a wire contact pattern corresponding to the I/O contact pattern on the readout surface, the wire contacts being in electrical communication with wire bonding pads mounted on the intermediate substrate; and

electrically conductive bonds discretely connecting each pixel contact in the pixel pattern to the first end of the corresponding conductive via passage of the entry passage pattern, and connecting each transmission contact in the transmission contact pattern to the second end of the corresponding conductive via passage of the exit passage pattern, and connecting each I/O contact in the I/O contact pattern with the corresponding wire contact in the wire contact pattern on the intermediate substrate.

2. The radiation energy imaging device of claim 1, wherein the detector substrate is a temperature sensitive, compound semiconductor substrate.

3. The radiation energy imaging device of claim 1, wherein the detector substrate comprises an element selected from the group consisting of Cadmium and Tellurium.

4. The radiation energy imaging device of claim 1, wherein the intermediate substrate has the wire contacts recessed into the exit face of the intermediate substrate.

5. The radiation energy imaging device of claim 1, wherein the intermediate substrate has conductive via passages having a lining comprised of an electrically conductive material to make the passage conductive.

6. The intermediate substrate of claim 5, wherein the conductive via passages have a lining comprised of an electrically conductive material selected from the group consisting of Copper, Gold, Silver, Nickel, Aluminum, Platinum, Lead, Tin, Bismuth and Indium.

7. The intermediate substrate of claim 5, wherein the intermediate substrate further comprises a material selected from the group consisting of:

a printed circuit board, a photo-resist material, an FR4 material, a ceramic material.

8. The radiation energy imaging device of claim 1, wherein the intermediate substrate has conductive via passages that are filled with an electrically conductive material to make the passage conductive.

9. The intermediate substrate of claim 5, wherein the conductive via passages each electrically communicates with a discrete conductive skirt at the end of passage on at least one of the faces of the intermediate substrate.

10. The radiation energy imaging device of claim 1, wherein the electrically conductive bonds comprise bump-bonds.

11. The radiation energy imaging device of claim 1, wherein the electrically conductive bonds comprise solder bump-bonds.

12. The radiation energy imaging device of claim 1, wherein the electrically conductive bonds comprise a conductive adhesive.

13. The radiation energy imaging device of claim 1, wherein the electrically conductive bonds comprise an anisotropically conductive adhesive.

14. The radiation energy imaging device of claim 1, comprising a plurality of detector substrates, a plurality of ASIC readout substrates bonded to a single intermediate substrate.

16. A method of producing a radiation energy imaging device of claim 1 comprising the steps of:

providing an intermediate substrate having an entry face and an exit face, a plurality of discrete conductive via passages having two ends, a first end at the entry face disposed in an entry passage pattern corresponding to a pixel pattern of a detector substrate and a second end at the exit face disposed in an exit passage pattern corresponding to a transmission contact pattern of a readout substrate, and a plurality of wire contacts on the exit face disposed in a wire contact pattern corresponding to the I/O contact pattern of a readout substrate, the wire contacts being in electrical communication with wire bonding pads mounted on the intermediate substrate;

applying conductive bumps to the conductive via passages and any wire contacts on a face of the intermediate substrate to provide an intermediate substrate face with solder bumped contacts;

positioning an appropriate semiconductor substrate in juxtaposition with the intermediate substrate face with solder bumped contacts, with the solder bumped contacts closely proximate the corresponding contacts on the semiconductor substrate; and

causing the conductive bumped contacts to bond under appropriate conditions of heat and pressure and to form bump-bonds between the conductive bumped contacts of the intermediate substrate and the corresponding contacts on the semiconductor substrate to produce the radiation energy imaging device of claim 1.

17. A method of producing a radiation energy imaging device of claim 16, wherein the applying step and the positioning step comprise:

applying conductive bumps to the conductive contacts and any wire contacts on a face of a semiconductor substrate to provide a semiconductor substrate face with solder bumped contacts; and

positioning the semiconductor substrate face with conductive bumped contacts in juxtaposition with an appropriate intermediate substrate face of the intermediate substrate, with the conductive bumped contacts closely proximate the corresponding contacts on the appropriate intermediate substrate face.

18. A method of producing a radiation energy imaging device of claim 1 comprising the steps of:

providing an intermediate substrate having an entry face and an exit face, a plurality of discrete conductive via passages having two ends, a first end at the entry face disposed in an entry passage pattern corresponding to a pixel pattern of a detector substrate and a second end at the exit face disposed in an exit passage pattern corresponding to a transmission contact pattern of a readout substrate, and a plurality of wire contacts on the exit face disposed in a wire contact pattern corresponding to the I/O contact pattern of a readout substrate, the wire contacts being in electrical communication with wire bonding pads mounted on the intermediate substrate;

applying a conductive adhesive to the conductive via passages and any wire contacts on a face of the intermediate substrate to provide an intermediate substrate face with conductive adhesive coated contacts;

positioning an appropriate semiconductor substrate in juxtaposition with the intermediate substrate face with the conductive adhesive coated contacts, and with the conductive adhesive coated contacts closely proximate the corresponding contacts on the semiconductor substrate; and

causing the conductive adhesive of the conductive adhesive coated contacts under appropriate conditions of heat and pressure to conductively adhere the contacts of the intermediate substrate to the corresponding contacts on the semiconductor substrate to produce the radiation energy imaging device of claim 1.

19. A method of producing a radiation energy imaging device of claim 18, wherein the applying step and the positioning step comprise:

applying a conductive adhesive to the conductive contacts and any wire contacts on a face of a semiconductor substrate to provide a semiconductor substrate face with conductive adhesive coated contacts; and

positioning the semiconductor substrate face with the conductive adhesive coated contacts in juxtaposition with an appropriate intermediate substrate face of the intermediate substrate, with the conductive adhesive coated contacts closely proximate the corresponding contacts on the appropriate intermediate substrate face.

20. A method of producing a radiation energy imaging device of claim 18, wherein the conductive adhesive is an anisotropically conductive adhesive.

15. An x-ray and gamma-ray radiation energy imaging device comprising:

a semiconductor detector substrate and a semiconductor readout/processing substrate both mounted on opposite sides of, and electrically communicating with each other, through an intermediate substrate, the substrates all being substantially planar, with the readout/processing substrate and the detector substrate each having a perimeter, the readout/processing substrate perimeter falling within the shadow of the detector substrate perimeter of the corresponding detector substrate with which it electrically communicates, and the readout/processing substrate having circuitry contacts all of which circuitry contacts are disposed on a surface of the semiconductor readout/processing substrate that electrically communicates with the intermediate substrate, and substantially all electrical communication to and from the semiconductor readout/processing substrate being routed through the intermediate substrate by way of the circuitry contacts.