Radiation detector unit with three-side buttable read-out integrated circuit and method of making thereof
A radiation detector unit includes a read-out integrated circuit (ROIC) including a plurality of core circuit blocks located on a continuous uninterrupted substrate adjacent to one another along a first direction, and a plurality of radiation sensors bonded to a front side surface of the ROIC, where each radiation sensor of the plurality of radiation sensors is bonded to a respective core circuit block of the plurality of core circuit blocks of the ROIC. Additional embodiments include detector modules and detector arrays formed by assembling the detector units, and methods of operating and manufacturing the same.
1. A radiation detector unit, comprising:
a read-out integrated circuit (ROIC) comprising a plurality of core circuit blocks located on a continuous uninterrupted substrate adjacent to one another along a first direction; and
a plurality of radiation sensors bonded to a front side surface of the ROIC, wherein each radiation sensor of the plurality of radiation sensors is bonded to a respective core circuit block of the plurality of core circuit blocks of the ROIC,
wherein the radiation sensors are directly bonded to the front side surface of the ROIC such that no interposer is used to route event detection signals from the radiation sensors to the core circuit blocks of the ROIC, and
the ROIC further comprises a power bus that extends from a peripheral circuit block to each of the core circuit blocks along the first direction, and wherein each of the core circuit blocks comprises a low dropout regulator configured to provide an identical supply voltage to each of the core circuit blocks.
2. The radiation detector unit of claim 1 , wherein the peripheral circuit block is located on the continuous uninterrupted substrate of the ROIC adjacent to the plurality of core circuit blocks along the first direction.
3. The radiation detector unit of claim 2 , wherein each core circuit block of the ROIC is configured to receive event detection signals from a radiation sensor and convert the event detection signals to digital detection signals.
4. The radiation detector unit of claim 3 , wherein the ROIC further comprises a local processing unit configured to perform operations comprising at least one of:
data compression or buffering of the digital detection signals generated by the core circuit blocks;
providing updated temperature data;
providing updated non-conforming pixel data;
error correction;
dynamic detection of bad pixels;
minimodule neighbor recognition; or
non-conforming pixel list re-configuration.
5. The radiation detector unit of claim 2 , wherein:
the peripheral circuit block is located adjacent to a first peripheral edge of the ROIC; and the plurality of core circuit blocks comprise N instances of an identical core circuit block extending adjacent to one another along the first direction to a second peripheral edge of the ROIC that is opposite the first peripheral edge of the ROIC, where N is an integer >1.
6. The radiation detector unit of claim 5 , wherein each core circuit block includes at least N output data channels for transmitting digital detection signals to the adjacent circuit block that is more proximate to the first peripheral edge of the ROIC, and at least N−1 input data channels for receiving digital detection signals from the adjacent circuit block that is more proximate to the second peripheral edge of the ROIC.
7. The radiation detector unit of claim 2 , further comprising a carrier board, wherein the ROIC is located over the front side surface of the carrier board, the carrier board comprises a bond pad region on the front side surface of the carrier board, and a plurality of wire bonds electrically connect bond pads on the peripheral circuit block of the ROIC to bond pads of the bond pad region of the ROIC.
8. The radiation detector unit of claim 1 , wherein:
the continuous uninterrupted substrate does not contain gaps between the adjacent core circuit blocks; and
the adjacent core circuit blocks are formed by photolithographic stitching on the continuous uninterrupted substrate and do not contain a gap between them.
9. A detector module, comprising:
the radiation detector unit of claim 4 ;
a second radiation detector unit, comprising:
a second read-out integrated circuit (ROIC) comprising a plurality of core circuit blocks adjacent to one another along the first direction; and
a second plurality of radiation sensors bonded to a front side surface of the second ROIC, wherein each radiation sensor of the second plurality of radiation sensors is bonded to a respective core circuit block of the plurality of core circuit blocks of the second ROIC; and
a support member,
wherein the radiation detector unit and the second radiation detector unit are arranged on the support member such that a first peripheral edge of the radiation detector unit abuts a first peripheral edge of the second radiation detector unit along the first direction and the plurality of radiation sensors and the second plurality of radiation sensors form a continuous detector surface having a length of at least 8 cm along the first direction.
10. The detector module of claim 9 , wherein:
the plurality of radiation sensors and the second plurality of radiation sensors form a continuous detector surface having a length of at least 16 cm along the first direction;
the plurality of core circuit blocks of the second ROIC are located on a second continuous uninterrupted substrate adjacent to one another along the first direction, the second continuous uninterrupted substrate does not contain gaps between the adjacent core circuit blocks of the second ROIC, and the adjacent core circuit blocks of the second ROIC are formed by photolithographic stitching on the second continuous uninterrupted substrate and do not contain a gap between them; and
a gap extends between the continuous uninterrupted substrate and the second continuous uninterrupted substrate, and between the plurality of core circuit blocks of the ROIC and the plurality of core circuit blocks of the second ROIC.
11. The radiation detector unit of claim 1 , wherein length and width dimensions of each of the core circuit blocks is substantially equal to the length and width dimensions of the radiation sensors bonded to the respective core circuit blocks.
12. The radiation detector unit of claim 11 , wherein the combined length dimension of the plurality of core circuit blocks along the first direction is between 4 cm and 20 cm.
13. The radiation detector unit of claim 12 , wherein the combined length dimension of the plurality of core circuit blocks along the first direction is 8 cm to 16 cm.
14. The radiation detector unit of claim 1 , wherein each of the radiation sensors comprises an array of pixel sensors, wherein each pixel sensor of the array of pixel sensors has a dimension in the first direction that is 25-80% larger than the dimension of the pixel sensor in a second direction that is perpendicular to the first direction.
15. A detector module, comprising:
the radiation detector unit of claim 1 ; and
a module circuit board electrically coupled to the radiation detector unit.
16. The detector module of claim 15 , further comprising a support member which comprises a frame bar having a front side surface and a backside surface, wherein the radiation detector unit is mounted to the front side surface of the frame bar, and the module circuit board is attached to the frame bar such that first and second major surfaces of the module circuit board extend away from the backside surface of the frame bar along a direction that is perpendicular to a top surface of the continuous uninterrupted substrate which supports the ROIC.
17. A detector array, comprising:
a detector array frame; and
a plurality of detector modules of claim 15 mounted to the detector array frame such that the radiation detector units of the plurality of detector modules abut one another along a second direction that is perpendicular to the first direction.
18. A computed tomography system comprising:
an X-ray radiation source configured to emit an X-ray;
the detector array of claim 17 , wherein the detector array is configured to receive the X-ray from the X-ray radiation source through an intervening space configured to contain an object therein; and
an image reconstruction system including a computer configured to run an automated image reconstruction algorithm on detection signals generated from the detector array.