Readout chip for detectors

Abstract

The present application provides a readout chip for a detector, a detector module and an X-ray system, wherein the readout chip for the detector comprises: a plurality of pixel input pads PADs arranged in a matrix and distributed in the central area of ​​the readout chip; an auxiliary PAD different from the pixel input PAD and distributed at the edge of the readout chip; at least one guard ring internal PAD distributed between the plurality of pixel input PADs and the auxiliary PAD; and a guard ring bonding PAD distributed on the same side of the auxiliary PAD, wherein at least one guard ring internal PAD is connected to the guard ring bonding PAD so as to apply a bias voltage to the at least one guard ring internal PAD through the guard ring bonding PAD, and a connection line between the at least one guard ring internal PAD and the guard ring bonding PAD is not interconnected with other connection lines in the readout chip.

Description

Technical Field

[0001] The present disclosure relates to the field of X-ray radiation, and more particularly to a readout chip for a detector in an X-ray radiation system. Background Art

[0002] X-ray imaging systems are usually composed of detectors, readout circuits / chips, data transmission and storage, and host computer software. The detectors are usually linear or planar array photodetectors, and the readout circuits / chips are used to read out the electrical signals of the detectors. They and the detectors are both core components of the imaging system.

[0003] However, the process of directly flipping the array detector and its readout chip is complex and has low reliability, and the energy resolution capability of the detector is not high enough. Summary of the invention

[0004] In order to solve the above problems, in the first aspect of the present application, a readout chip for a detector is provided, which may include: a plurality of pixel input pads PADs arranged in a matrix and distributed in the central area of ​​the readout chip; an auxiliary PAD different from the pixel input PAD and distributed at the edge of the readout chip; at least one guard ring internal PAD distributed between the plurality of pixel input PADs and the auxiliary PAD; and a guard ring bonding PAD distributed on the same side of the auxiliary PAD, wherein the at least one guard ring internal PAD is connected to the guard ring bonding PAD to apply a bias to the at least one guard ring internal PAD through the guard ring bonding PAD, and the connecting wires between the at least one guard ring internal PAD and the guard ring bonding PAD are not interconnected with other connecting wires in the readout chip.

[0005] According to the first aspect of the present application, when the bias voltage applied to the guard ring bonding PAD is greater than the power supply voltage of the readout chip, the interconnection line between the at least one guard ring internal PAD and the guard ring bonding PAD is shielded by other metal lines.

[0006] According to the first aspect of the present application, when the readout chip is used for a three-side spliced ​​detector, the auxiliary PAD, the guard ring bonding PAD, and the at least one guard ring internal PAD are all arranged on a side that is not spliced.

[0007] In a second aspect of the present application, a detector module is provided, which may include: a detector; and a readout chip, wherein the detector is flip-chip mounted on the readout chip, and the readout chip includes: a plurality of pixel input pads PAD arranged in a matrix and distributed in a central area of ​​the readout chip; an auxiliary PAD different from the pixel input PAD and distributed at an edge of the readout chip; at least one guard ring internal PAD distributed between the plurality of pixel input PADs and the auxiliary PAD; and a guard ring bonding PAD distributed on the same side of the auxiliary PAD, wherein the at least one guard ring internal PAD is connected to the guard ring bonding PAD to apply a bias to the at least one guard ring internal PAD through the guard ring bonding PAD, and the connecting wires between the at least one guard ring internal PAD and the guard ring bonding PAD are not interconnected with other connecting wires in the readout chip.

[0008] According to the second aspect of the present application, when the bias voltage applied to the guard ring bonding PAD is greater than the power supply voltage of the readout chip, the interconnection line between the at least one guard ring internal PAD and the guard ring bonding PAD is shielded by other metal lines.

[0009] According to the second aspect of the present application, when the readout chip is used for a three-side spliced ​​detector, the auxiliary PAD, the guard ring bonding PAD, and the at least one guard ring internal PAD are all arranged on a side that is not spliced.

[0010] In a third aspect of the present application, an X-ray system is provided, comprising the detector module according to the second aspect.

[0011] The present application designs a PAD inside the readout chip that is specifically used to interconnect with the guard ring electrode of the detector, thereby simplifying the flip-packaging process of the detector module, improving the reliability of the detector module, reducing the cost of the detector module, and further improving the energy resolution capability of the detector module. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] The above and other embodiments and features of the present disclosure will become more apparent by describing in detail embodiments of the present disclosure with reference to the accompanying drawings, in which:

[0013] Figure 1 A diagram schematically showing an example arrangement of a detector and a readout circuit in an X-ray imaging system according to an embodiment of the present disclosure;

[0014] Figure 2 Schematically shows a schematic diagram of the layout design of a 36×36 pixel photon counting readout chip according to an embodiment of the present disclosure;

[0015] Figure 3A schematic diagram of a layout design of a readout chip having a guard ring pad PAD according to an embodiment of the present disclosure is schematically shown. DETAILED DESCRIPTION

[0016] The specific embodiments of the present invention will be described in detail below. It should be noted that the embodiments described herein are only for illustration and are not intended to limit the present invention. In the following description, a large number of specific details are set forth in order to provide a thorough understanding of the present invention. However, it is obvious to those of ordinary skill in the art that these specific details do not have to be used to implement the present invention. In other examples, in order to avoid confusing the present invention, known circuits, materials or methods are not specifically described.

[0017] Throughout the specification, references to "one embodiment," "an embodiment," "an example," or "an example" mean that a particular feature, structure, or characteristic described in conjunction with the embodiment or example is included in at least one embodiment of the present invention. Thus, the phrases "in one embodiment," "in an embodiment," "an example," or "an example" appearing in various places throughout the specification do not necessarily all refer to the same embodiment or example. Furthermore, particular features, structures, or characteristics may be combined in one or more embodiments or examples in any appropriate combinations and / or subcombinations.

[0018] It should be understood that when an element is said to be "coupled to" or "connected to" another element, it can be directly coupled or connected to the other element or there may be intermediate elements. On the contrary, when an element is said to be "directly coupled to" or "directly connected to" another element, there are no intermediate elements.

[0019] Furthermore, as used herein, the term "and / or" includes any and all combinations of one or more of the associated listed items.

[0020] It will be understood that a noun corresponding to a term in the singular form may include one or more things unless the relevant context clearly indicates otherwise. As used herein, each of phrases such as "A or B," "at least one of A and B," "at least one of A or B," "A, B or C," "at least one of A, B and C," and "at least one of A, B or C" may include all possible combinations of items listed together with a corresponding one of the plurality of phrases. As used herein, terms such as "1st" and "2nd" or "first" and "second" may be used to simply distinguish a corresponding component from another component and do not limit the components in other respects (e.g., importance or order).

[0021] As used herein, the term "circuit" may include units implemented in hardware, software, or firmware, and may be used interchangeably with other terms (e.g., "logic," "logic block," "portion," or "module"). A module may be a single integrated component adapted to perform one or more functions or a minimum unit or portion of the single integrated component. For example, according to an embodiment, a module may be implemented in the form of an application specific integrated circuit (ASIC).

[0022] It should be understood that the various embodiments of the present disclosure and the terms used therein are not intended to limit the technical features set forth herein to specific embodiments, but include various changes, equivalent forms or replacement forms for the corresponding embodiments. Unless otherwise clearly defined herein, all terms will be given their broadest possible interpretation, including the meanings implied in the specification and the meanings understood by those skilled in the art and / or defined in dictionaries, papers, etc.

[0023] In addition, it should be understood by those skilled in the art that the drawings provided herein are for illustrative purposes and are not necessarily drawn to scale. For the description of the drawings, similar reference numerals may be used to refer to similar or related elements. The present disclosure will be described exemplarily with reference to the drawings below.

[0024] Readout chip

[0025] It should be noted that in the fields of security inspection, non-destructive testing and medical imaging, in order to obtain better image quality and more accurate material identification at a lower X-ray irradiation dose, large-scale pixel detectors and matching pixel single photon counting readout chips (a type of readout circuit / chip) are developed, and the pixel detector electrodes and the readout chips are interconnected through a flip-chip process. The interconnected detectors and chips are called detector modules. A typical pixel detector module is as follows: Figure 1 As shown in FIG. 1 , it is mainly composed of a PCB, a readout chip (or a readout circuit), bumps, and a detector. A pixel-type detector module can be used for independent imaging or energy spectrum detection, or multiple detector modules can be spliced ​​together to achieve radiation imaging or energy spectrum detection over a larger area.

[0026] In order to achieve large-area imaging or energy spectrum detection of pixel-type detector modules, the pixel input pads PAD in the readout circuit / chip are usually distributed in the internal matrix of the chip, while the power PAD, data input / output module PAD, bias circuit PAD and other PADs are usually fanned out from one side of the chip; for chips that do not require multi-detector splicing, except for the pixel input PAD distributed in the center of the chip, other PADs can be distributed around the chip.

[0027] Figure 2The schematic diagram of the layout design of a 36×36 pixel photon counting readout chip is shown. In the figure, the input PADs of the pixel units are distributed in a matrix in the central area, while other PADs, such as the power PAD, the PAD of the data input / output module, and the PAD of the bias circuit, are distributed on the right side of the chip. Through such an arrangement, multiple detector modules can be spliced ​​in the other three directions of the power PAD, the PAD of the data input / output module, and the bias circuit PAD fan-out direction.

[0028] For semiconductor single-photon detectors such as cadmium zinc telluride, cadmium telluride, and silicon, in order to improve the energy resolution capability of the detector, a guard ring can be made around the anode plane of the detector. The guard ring can be used to form an electric field and reduce the leakage current of the detector, and can realize a unipolar sensitive charge collection method, thereby improving the energy resolution capability of the detector.

[0029] However, usually, the detector's guard ring is a certain distance away from the edge of the anode. Figure 1 The pixel detector readout chip in the detector module that uses the flip-package technology to interconnect the detector and the readout circuit / chip, if the chip PAD is still in accordance with Figure 2 If the chip is not arranged like that, or if the chip does not have an interconnect PAD specifically designed for the detector guard ring electrode, then the guard ring electrode on the detector anode plane needs to be led out and connected to the ground potential or other potential in other ways, such as by making a metal wire between the chip and the detector to connect the detector guard ring electrode. This will add additional process steps and increase the cost of the detector module. If the detector guard ring is suspended, the advantages of making a guard ring will not be brought into play.

[0030] In order to solve this problem, the present application provides a readout chip for a detector, a detector module consisting of a detector and a readout chip, and an X-ray system including the detector module, wherein the readout chip for the detector may include: a plurality of pixel input pads PADs arranged in a matrix and distributed in the central area of ​​the readout chip; an auxiliary PAD different from the pixel input PAD and distributed at the edge of the readout chip; at least one guard ring internal PAD distributed between the plurality of pixel input PADs and the auxiliary PAD; and a guard ring bonding PAD distributed on the same side of the auxiliary PAD, wherein at least one guard ring internal PAD is connected to the guard ring bonding PAD to apply a bias to the at least one guard ring internal PAD through the guard ring bonding PAD, and a connecting line between at least one guard ring internal PAD and the guard ring bonding PAD is not interconnected with other connecting lines in the readout chip.

[0031] Figure 2The layout design of the 36×36 pixel photon counting readout chip shown in is a layout design of a readout chip suitable for a detector module that can be spliced ​​on three sides. The following description will be made by taking the readout chip suitable for a detector module that can be spliced ​​on three sides as an example, but those skilled in the art should understand that the present application is not limited thereto, and the principles disclosed in the present application can be used for any suitable readout chip as needed.

[0032] Figure 3 A schematic diagram of a layout design of a readout chip having a guard ring pad PAD according to an embodiment of the present disclosure is schematically shown.

[0033] like Figure 3 As shown, multiple pixel input PADs are distributed in a matrix form in the central area of ​​the readout chip, and other auxiliary PADs different from the pixel input PADs (for example, power supply PAD, data input / output module PAD, bias circuit PAD) are distributed on the right side of the readout chip (in this example, the right side is considered to be the side that does not need splicing).

[0034] In order to prevent the guard ring from being suspended in the air, the present application sets a guard ring internal PAD in the area between the pixel input PAD and the auxiliary PAD (for example, Figure 3 17A and 17B) so that when the detector is flip-chip mounted on the readout chip, the guard ring can be flip-chip mounted on the readout chip at the same time as the detector.

[0035] For the guard ring to work, a bias needs to be applied to the guard ring. To this end, a guard ring bonding PAD is provided near the PAD inside the guard ring, so as to apply a bias to the PAD inside the guard ring through the guard ring bonding PAD. In this example, the guard ring bonding PAD can be provided on the same side as the auxiliary PAD. Those skilled in the art should understand that the position of the guard ring bonding PAD is not limited to this, for example, it can be provided at a position on the lower side or upper side of the PAD inside the guard ring, which can be provided differently according to requirements.

[0036] When in use, the PADs 17A and 17B inside the guard ring are interconnected with the guard ring bonding PAD 17 and are connected to other metal connection lines in different readout chips.

[0037] Preferably, when the bias voltage applied to the guard ring bonding PAD is greater than the power supply voltage of the readout chip, the connection lines between the guard ring bonding PAD 17A and 17B and the guard ring bonding PAD 17 can be shielded by using ground wires or other metal wires, thereby effectively preventing the connection lines between the guard ring bonding PAD 17A and 17B and the guard ring bonding PAD 17 from interfering with other connection lines in the readout chip.

[0038] When the bias voltage applied to the guard ring bonding PAD is less than the power supply voltage of the readout chip, the interconnection line between at least one guard ring internal PAD and the guard ring bonding PAD may be shielded by other metal lines or may not be shielded.

[0039] In an exemplary embodiment, multiple sets of guard ring inner PADs 17A and 17B and guard ring bonding PADs 17 may be provided on one side of the readout chip as needed, for example Figure 3 As shown in the figure numeral 18.

[0040] In an exemplary embodiment, the number of PADs inside the guard ring may be one or more.

[0041] As mentioned above, Figure 3 The chip layout shown in FIG. 1 is suitable for a detector module that can be spliced ​​on three sides. When the detector module does not need to be spliced, the guard ring internal PADs 17A and 17B and the guard ring bonding PAD 17 can be set on either side of the readout chip.

[0042] Alternatively, the guard ring inner PADs 17A and 17B may be disposed on one side of the readout chip, and the guard ring bonding PAD 17 may be disposed on the other side of the readout chip.

[0043] Alternatively, the guard ring inner PADs 17A, 17B and the guard ring bonding PAD 17 may be provided between the auxiliary PADs.

[0044] Detector module

[0045] The above referenced Figure 3 An improved readout chip having a PAD inside a guard ring and a guard ring bonding PAD according to an embodiment of the present application is described.

[0046] Based on the improved readout chip, the detector can be mounted on the improved readout chip by flip-chip technology, and the guard ring is correspondingly connected to the internal PAD of the guard ring on the readout chip, thereby forming a new detector module.

[0047] X-ray system

[0048] Based on the novel detector module described above, a new X-ray system can be formed.

[0049] In order to simplify the description, the novel detector module and the novel X-ray system including the same will not be described again.

[0050] Although the above embodiments are described by taking a pixel-type single photon counter chip as an example, those skilled in the art should understand that the technical solutions described in the present disclosure may also be used in any other suitable circuits.

[0051] In addition, although the above description uses semiconductor detectors as an example, those skilled in the art should understand that the detectors are not limited to semiconductor detectors, but may be, for example, silicon, photodiodes, cadmium zinc telluride, or cadmium telluride; nor are they limited to scintillators or other detectors, such as perovskite detectors.

[0052] The above description is mainly based on hardware, but those skilled in the art should understand that corresponding hardware can execute corresponding methods accordingly.

[0053] In order to simplify the description, the functions and methods performed by the hardware circuit will not be elaborated in detail here.

[0054] It will be appreciated by those skilled in the art that the features described in the various embodiments and / or claims of the present disclosure may be combined and / or combined in a variety of ways, even if such combinations and / or combinations are not explicitly described in the present disclosure. In particular, the features described in the various embodiments and / or claims of the present disclosure may be combined and / or combined in a variety of ways without departing from the spirit and teachings of the present disclosure. All of these combinations and / or combinations fall within the scope of the present disclosure.

[0055] The embodiments of the present disclosure are described above. However, these embodiments are only for illustrative purposes and are not intended to limit the scope of the present disclosure. Although the embodiments are described above separately, this does not mean that the measures in the various embodiments cannot be used in combination to advantage. The scope of the present disclosure is defined by the attached claims and their equivalents. Without departing from the scope of the present disclosure, those skilled in the art may make a variety of substitutions and modifications, which should all fall within the scope of the present disclosure.

Claims

1. A readout chip for a detector, comprising: a plurality of pixel input pads arranged in a matrix and distributed at a central area of ​​the readout chip; Auxiliary pads distributed at the edge of the readout chip and different from the pixel input pads; at least one guard ring inner pad distributed between the plurality of pixel input pads and the auxiliary pad; and A guard ring bonding pad is distributed on the same side of the auxiliary pad, wherein The at least one guard ring inner pad is connected to the guard ring wire bonding pad so as to apply a bias voltage to the at least one guard ring inner pad through the guard ring wire bonding pad, and the connecting wire between the at least one guard ring inner pad and the guard ring wire bonding pad is not interconnected with other connecting wires in the readout chip.

2. The readout chip according to claim 1, wherein: When the bias voltage applied to the guard ring bonding pad is greater than the power supply voltage of the readout chip, the interconnection line between the at least one guard ring inner pad and the guard ring bonding pad is shielded by other metal lines.

3. The readout chip according to claim 1, wherein: In the case where the readout chip is used for a detector with three-side splicing, the auxiliary pad, the guard ring wire bonding pad, and the at least one guard ring internal pad are all arranged on a side that is not spliced.

4. A detector module, comprising: detector; as well as A readout chip, wherein the detector is flip-mounted on the readout chip, and the readout chip comprises: a plurality of pixel input pads arranged in a matrix and distributed at a central area of ​​the readout chip; Auxiliary pads distributed at the edge of the readout chip and different from the pixel input pads; at least one guard ring inner pad distributed between the plurality of pixel input pads and the auxiliary pad; and A guard ring bonding pad is distributed on the same side of the auxiliary pad, wherein The at least one guard ring inner pad is connected to the guard ring wire bonding pad so as to apply a bias voltage to the at least one guard ring inner pad through the guard ring wire bonding pad, and the connecting wire between the at least one guard ring inner pad and the guard ring wire bonding pad is not interconnected with other connecting wires in the readout chip.

5. The detector module according to claim 4, wherein: When the bias voltage applied to the guard ring bonding pad is greater than the power supply voltage of the readout chip, the interconnection line between the at least one guard ring inner pad and the guard ring bonding pad is shielded by other metal lines.

6. The detector module according to claim 4, wherein: In the case where the readout chip is used for a detector with three-side splicing, the auxiliary pad, the guard ring wire bonding pad, and the at least one guard ring internal pad are all arranged on a side that is not spliced.

7. An X-ray system comprising a detector module according to any one of claims 4-6.

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