Side-incident image sensor with protruding integrated circuit chip

Abstract

A system with an image sensor comprising: M metal layers (i) and M radiation detectors (i), i = 1, …, M. M is an integer greater than 1. The radiation detector (i) comprises a radiation absorption layer (i) and integrated circuit chips (i, j), j = 1, …, Ni. Ni, i = 1, …, M is a positive integer. The plurality of metal layers and the plurality of radiation absorption layers together form a layer stack. All sensing elements of one of the radiation detectors exist in a best-fit plane. Each of the integrated circuit chips (i, j), j = 1, …, Ni, at least partially overlaps the radiation absorption layer (i) in a direction perpendicular to the best-fit plane. There exists a first plane perpendicular to the best-fit plane, which intersects all integrated circuit chips and does not intersect any of the plurality of radiation absorption layers.

Description

[Background Technology]

[0001] A radiation detector is a device for measuring the characteristics of radiation. Examples of these characteristics may include the spatial distribution of the intensity, phase, and polarization of the radiation. The radiation measured by the radiation detector can be radiation that has already passed through an object. The radiation measured by the radiation detector can be electromagnetic radiation, such as infrared light, visible light, ultraviolet light, X-rays, or gamma rays. The radiation can also be other types, such as alpha rays and beta rays. An imaging system may include one or more image sensors, each of which may have one or more radiation detectors. [Summary of the Invention]

[0002] This document discloses a system including an image sensor comprising: M metal layers (metal layers (i), i = 1, ..., M) and M radiation detectors (radiation detectors (i), i = 1, ..., M), where M is an integer greater than 1. For each value of i, the radiation detector (i) includes a radiation absorption layer (i) and an integrated circuit chip (i, j), j = 1, ..., Ni, configured to process electrical signals generated in the radiation absorption layer (i). Ni, i = 1, ..., M are positive integers. The M metal layers and the radiation absorption layer (i), i = 1, ..., M together form a layer stack. All sensing elements of one of the M radiation detectors exist in a best-fit plane. For each value of i, each of the integrated circuit chips (i, j), j = 1, ..., Ni, at least partially overlaps the radiation absorption layer (i) in a direction perpendicular to the best-fit plane. There exists a first plane perpendicular to the best-fit plane, which intersects all the integrated circuit chips (i, j), i = 1, ..., M and j = 1, ..., Ni, and does not intersect any of the radiation-absorbing layers (i), i = 1, ..., M.

[0003] In one respect, the stack comprises 2×M layers.

[0004] In one respect, the M metal layers comprise metals with an atomic number of at least 26.

[0005] In one respect, the metal is tungsten, platinum, or gold.

[0006] On one hand, the M metal layers and the radiation absorbing layer (i), i = 1, ..., M, are arranged alternately in the stack.

[0007] On one hand, there exists a second plane perpendicular to the best-fit plane, which intersects all of the M metal layers and does not intersect any of the radiation-absorbing layers (i), i = 1, ..., M.

[0008] On one hand, the first plane is parallel to the second plane, and each point of the radiation absorbing layer (i), i = 1, ..., M, is located between the first plane and the second plane.

[0009] On one hand, the thickness of each of the M metal layers, measured in a direction perpendicular to the best-fit plane, is in the range of 50 micrometers to 100 micrometers.

[0010] In one respect, each of the integrated circuit chips (i, j), i = 1, ..., M and j = 1, ..., Ni, includes an application-specific integrated circuit (ASIC).

[0011] On one hand, the M metal layers are configured to block and absorb X-rays.

[0012] On one hand, the input / output device electrically connects external circuitry to electrodes on the integrated circuit chip (i, j), i = 1, ..., M and j = 1, ..., Ni, and the first plane is between (A) the electrodes and (B) the radiation absorption layer (i), i = 1, ..., M.

[0013] On one hand, for each value of i, the radiation-absorbing layer (i) comprises a plurality of discrete radiation-absorbing regions.

[0014] On the one hand, Ni, i = 1, ..., M are all 1.

[0015] In one respect, the radiation-absorbing layer (i), i = 1, ..., M, comprises GaAs, CdTe, or CdZnTe.

[0016] In one respect, the thickness of each of the integrated circuit chips (i, j), i = 1, ..., M and j = 1, ..., Ni, measured in a direction perpendicular to the best-fit plane, is in the range of 10 micrometers to 100 micrometers.

[0017] On one hand, for each value of i and each value of j, a portion of the integrated circuit chip (i, j) is sandwiched between the metal layer (i) and the radiation-absorbing layer (i).

[0018] On one hand, for each value of i, the metal layer (i) includes Pi gaps, where Pi is a positive integer not greater than Ni, and for each value of i, the integrated circuit chip (i, j), j = 1, ..., Ni is within the Pi gaps, such that there exists a straight line on the best-fit plane such that any travel from any point of the integrated circuit chip (i, j), j = 1, ..., Ni in any direction parallel to the straight line will impact the metal layer (i).

[0019] On the one hand, for every value of i, Ni > Pi.

[0020] On one hand, for each value of i, Ni = Pi, and for each value of i, the integrated circuit chip (i, j), j = 1, ..., Ni are respectively located in the Pi gaps.

[0021] On one hand, for each value of i, the thickness of each integrated circuit chip (i, j), j = 1, ..., Ni of the radiation detector (i) measured in the direction perpendicular to the best-fit plane is less than the thickness of the metal layer (i) measured in the direction perpendicular to the best-fit plane.

[0022] On one hand, for each value of i, each integrated circuit chip (i, j), j = 1, ..., Ni of the radiation detector (i) does not have direct physical contact with the radiation absorption layer of any other radiation detector among the M radiation detectors.

[0023] On one hand, each straight line segment on two adjacent radiation-absorbing layers (i), i = 1, ..., M, intersects with (A) at least one metal layer of the M metal layers or (B) at least one void in one of the M metal layers.

[0024] On one hand, each straight line segment on two adjacent radiation-absorbing layers (i), i = 1, ..., M, intersects one of the M metal layers.

[0025] In one aspect, the system also includes a radiation source. A straight line parallel to the best-fit plane intersects both the radiation source and the image sensor, and the first plane is not between the radiation source and the radiation-absorbing layer (i), i = 1, ..., M.

[0026] This document discloses a method using the above-described system. The method includes transmitting radiation from the radiation source to an object located between the radiation source and the image sensor; and capturing an image of the object using the image sensor based on the interaction between the radiation and the object. [Attached Image Description]

[0027] Figure 1 A radiation detector according to an embodiment is illustrated schematically.

[0028] Figure 2 A simplified cross-sectional view of a radiation detector according to an embodiment is shown schematically.

[0029] Figure 3 A detailed cross-sectional view of a radiation detector according to an embodiment is schematically shown.

[0030] Figure 4 A detailed cross-sectional view of a radiation detector according to an alternative embodiment is schematically shown.

[0031] Figure 5 A perspective view of a radiation detector according to an embodiment is shown schematically.

[0032] Figure 6 An image sensor according to an embodiment is schematically shown.

[0033] Figure 7 and Figure 8 An image sensor according to an alternative embodiment is illustrated schematically.

[0034] Figure 9 An imaging system according to an embodiment is illustrated schematically.

[0035] Figure 10 A flowchart illustrating the operation of a generalized imaging system according to an embodiment is shown.

[0036] Figure 11A and Figure 11B An alternative embodiment is shown. Figure 5 Radiation detector.

Detailed Implementation Methods

[0037] Radiation detector

[0038] Figure 1 A radiation detector 100 is schematically shown as an example. The radiation detector 100 may include an array of pixels 150 (also referred to as sensing elements 150). This array may be a rectangular array (such as...). Figure 1 (as shown), cellular array, hexagonal array, or any other suitable array. Figure 1 The example array of 150 pixels has 4 rows and 7 columns; however, in general, an array of 150 pixels can have any number of rows and any number of columns.

[0039] Each pixel 150 can be configured to detect radiation incident on it from a radiation source (not shown) and can be configured to measure characteristics of the radiation (e.g., particle energy, wavelength, and frequency). The radiation can include radiant particles such as photons (X-rays, gamma rays, etc.) and subatomic particles (alpha particles, beta particles, etc.). Each pixel 150 can be configured to count the number of radiant particles incident on it and whose energy falls into multiple energy bins over a period of time. All pixels 150 can be configured to count the number of radiant particles incident on it and falling into multiple energy bins simultaneously over the same period of time. When the incident radiant particles have similar energies, pixel 150 can be configured simply to count the number of radiant particles incident on it over a period of time without measuring the energy of individual radiant particles.

[0040] Each pixel 150 may have its own analog-to-digital converter (ADC) configured to digitize an analog signal representing the energy of an incident radiating particle into a digital signal, or to digitize an analog signal representing the total energy of multiple incident radiating particles into a digital signal. Pixels 150 may be configured to operate in parallel. For example, while one pixel 150 is measuring an incident radiating particle, another pixel 150 may be waiting for the radiating particle to arrive. Pixels 150 do not necessarily need to be individually addressable.

[0041] The radiation detector 100 described herein can be used in applications such as X-ray telescopes, X-ray mammography, industrial X-ray defect detection, X-ray microscopy or microradiography, X-ray casting inspection, X-ray non-destructive testing, X-ray welding inspection, and X-ray digital subtraction angiography. Using this radiation detector 100 in place of photographic plates, photographic films, light-excited phosphor plates (PSP plates), X-ray image intensifiers, scintillators, or other semiconductor X-ray detectors may be suitable.

[0042] Figure 2 The illustration schematically shows an embodiment. Figure 1 A simplified cross-sectional view of the radiation detector 100 along line 2-2. Specifically, the radiation detector 100 may include a radiation absorbing layer 110 and an electronic circuitry layer 120 (which may include one or more ASICs or application-specific integrated circuits) for processing and analyzing the electrical signals generated in the radiation absorbing layer 110 by incident radiation. The radiation detector 100 may or may not include a scintillator (not shown). The radiation absorbing layer 110 may include a semiconductor material such as silicon, germanium, GaAs, CdTe, CdZnTe, or combinations thereof. The semiconductor material may have a high-quality attenuation coefficient for the radiation of interest.

[0043] As an example, Figure 3 schematically shown Figure 1 A detailed cross-sectional view of the radiation detector 100 along line 2-2. Specifically, the radiation absorption layer 110 may include one or more diodes (e.g., pin or pn) formed by one or more discrete regions 114 of a first doped region 111 and a second doped region 113. The second doped region 113 may be separated from the first doped region 111 by an optional intrinsic region 112. The discrete regions 114 may be separated from each other by either the first doped region 111 or the intrinsic region 112. The first doped region 111 and the second doped region 113 may have opposite types of doping (e.g., the first doped region 111 is p-type and the second doped region 113 is n-type, or the first doped region 111 is n-type and the second doped region 113 is p-type). Figure 3 In the example, each discrete region 114 of the second doped region 113 forms a diode with the first doped region 111 and an optional intrinsic region 112. That is, in Figure 3 In the example, the radiation-absorbing layer 110 has multiple diodes (more specifically, 7 diodes corresponding to...). Figure 1 The array has 7 pixels (150) per row; for simplicity... Figure 3 Only two pixels 150 are marked in the image. Multiple diodes may have electrical contacts 119A as a common electrode. The first doped region 111 may also have multiple discrete portions.

[0044] Electronic circuitry layer 120 may include electronic system 121 adapted to process or interpret signals generated by radiation incident on radiation-absorbing layer 110. Electronic system 121 may include analog circuitry such as filter networks, amplifiers, integrators, and comparators, or digital circuitry such as microprocessors and memories. Electronic system 121 may include one or more analog-to-digital converters. Electronic system 121 may include components shared by multiple pixels 150 or components dedicated to a single pixel 150. For example, electronic system 121 may include an amplifier dedicated to each pixel 150 and a microprocessor shared among all pixels 150. Electronic system 121 may be electrically connected to pixels 150 via vias 131. The space between vias may be filled with filler material 130, which may increase the mechanical stability of the connection between electronic circuitry layer 120 and radiation-absorbing layer 110. Other bonding techniques may connect electronic system 121 to pixels 150 without using vias 131.

[0045] When radiation from a radiation source (not shown) impacts the radiation-absorbing layer 110 of a diode, the radiation particles can be absorbed and generate one or more charge carriers (e.g., electrons, holes) through various mechanisms. The charge carriers can drift to the electrode of one of the diodes under an electric field. This electric field can be an external electric field. Electrical contacts 119B can include multiple discrete portions, each electrically contacting a discrete region 114. The term "electrical contact" is used interchangeably with the term "electrode." In one embodiment, charge carriers can drift in multiple directions such that the charge carriers generated by a single radiation particle are substantially not shared by two different discrete regions 114 (here, "substantially not shared" means that less than 2%, less than 0.5%, less than 0.1%, or less than 0.01% of these charge carriers flow to a discrete region of the plurality of discrete regions 114 that is different from the discrete region to which the remaining charge carriers flow). The charge carriers generated by radiating particles incident on the footprint of one of these discrete regions 114 are substantially not shared by the other discrete regions 114. A pixel 150 associated with a particular discrete region 114 can be a region surrounding that discrete region 114 in which substantially all (more than 98%, more than 99.5%, more than 99.9%, or more than 99.99%) of the charge carriers generated by radiating particles incident therein flow towards that discrete region 114. That is, less than 2%, less than 1%, less than 0.1%, or less than 0.01% of these charge carriers flow out of that pixel 150.

[0046] Figure 4 An illustration of an alternative embodiment is shown. Figure 1 A detailed cross-sectional view of the radiation detector 100 along line 2-2. More specifically, the radiation absorbing layer 110 may include resistors made of semiconductor materials such as silicon, germanium, GaAs, CdTe, CdZnTe, or combinations thereof, but not diodes. The semiconductor material may have a high-quality attenuation coefficient for the radiation of interest. In one embodiment, Figure 4 The electronic circuit layer 120 is similar in structure and function to Figure 3 The electronic circuit layer 120.

[0047] When radiation impacts the radiation-absorbing layer 110, which includes resistors but not diodes, it can be absorbed and generate one or more charge carriers through various mechanisms. The radiating particles can generate 10 to 100,000 charge carriers. These charge carriers can drift to electrical contacts 119A and 119B under an electric field. This electric field can be an external electric field. Electrical contact 119B can include multiple discrete sections. In one embodiment, charge carriers can drift in multiple directions such that charge carriers generated by a single radiating particle are substantially not shared by two different discrete sections of electrical contact 119B (here, "substantially not shared" means that less than 2%, less than 0.5%, less than 0.1%, or less than 0.01% of these charge carriers flow to a discrete section different from the discrete section to which the remaining charge carriers flow). Charge carriers generated by radiating particles incident on the space occupied by one of these discrete sections of electrical contact 119B are substantially not shared by the other discrete section of electrical contact 119B. A pixel 150 associated with a discrete portion of the electrical contact 119B can be a region surrounding that discrete portion, in which substantially all (more than 98%, more than 99.5%, more than 99.9%, or more than 99.99%) of the charge carriers generated by incident radiant particles flow to that discrete portion of the electrical contact 119B. That is, less than 2%, less than 0.5%, less than 0.1%, or less than 0.01% of these charge carriers flow out of the pixel associated with that discrete portion of the electrical contact 119B.

[0048] Radiation detector with prominent integrated circuit chip

[0049] Figure 5 A perspective view of a radiation detector 105 according to an embodiment is shown schematically. In one embodiment, the radiation detector 105 may include a radiation absorbing layer 115 and one or more integrated circuit chips 125 (e.g., two integrated circuit chips 125a and 125b as shown in the figure).

[0050] In one embodiment, the radiation detector 105 can be similar to Figures 1 to 4 The radiation detector 100 is similar in structure and function to the radiation absorption layer 110 of the radiation detector 100, because (A) the radiation absorption layer 115 of the radiation detector 105 is similar in structure and function to the radiation absorption layer 110 of the radiation detector 100, and (B) the integrated circuit chip 125 of the radiation detector 105 is similar in function to the electronic circuit layer 120 of the radiation detector 100.

[0051] Specifically, in one embodiment, the integrated circuit chip 125 of the radiation detector 105 may be configured to process electrical signals generated in the radiation absorption layer 115. In one embodiment, each integrated circuit chip 125 may include an ASIC (Application-Specific Integrated Circuit).

[0052] Image sensor

[0053] Figure 6 A side view of an image sensor 600 according to an embodiment is schematically shown. In one embodiment, the image sensor 600 may include... Figure 5 Multiple radiation detectors 105 (e.g., three radiation detectors 105.1, 105.2, and 105.3 as shown in the figure). Radiation detectors 105.1, 105.2, and 105.3 may each include radiation absorption layers 115.1, 115.2, and 115.3, respectively.

[0054] Please note that each of the radiation detectors 105.1, 105.2, and 105.3 includes two integrated circuit chips 125; however, Figure 6 Only one of the two integrated circuit chips 125 is shown in the view because the other integrated circuit chip 125 is hidden from view. For example, the radiation detector 105.1 includes two integrated circuit chips 125a.1 and 125b.1, however, Figure 6 Only integrated circuit chip 125a.1 is shown in the view because integrated circuit chip 125b.1 is hidden in the view (integrated circuit chip 125b.1 is behind integrated circuit chip 125a.1). However, in Figure 7 The integrated circuit chip 125b.1 can be seen in it.

[0055] Layer stacking

[0056] In one embodiment, reference Figure 6 The image sensor 600 may also include a plurality of metal layers 610 corresponding one-to-one with the radiation detector 105 (e.g., three metal layers 610.1, 610.2, and 610.3 as shown). In one embodiment, the three metal layers 610.1, 610.2, and 610.3 together with the three radiation-absorbing layers 115.1, 115.2, and 115.3 form a stack of six layers (as shown).

[0057] In one embodiment, the three metal layers 610.1, 610.2, 610.3 and the three radiation-absorbing layers 115.1, 115.2, 115.3 can be arranged in an alternating manner in the stack (as shown in the figure). "Alternating manner" means that the multiple layers in the stack are arranged in the order of metal layer 610, then radiation-absorbing layer 115, then metal layer 610, then radiation-absorbing layer 115, and so on.

[0058] In one embodiment, the metal layer 610 of the image sensor 600 may include a metal with an atomic number of at least 26 (e.g., tungsten, platinum, and gold). In one embodiment, the metal layer 610 may block and absorb X-rays.

[0059] The integrated circuit chip was sandwiched in the middle

[0060] In one embodiment, reference Figure 6 Each integrated circuit chip 125 of the image sensor 600 may include a portion sandwiched between a corresponding metal layer 610 and a corresponding radiation-absorbing layer 115. For example, a portion of integrated circuit chip 125a.1 is sandwiched between a corresponding metal layer 610.1 and a corresponding radiation-absorbing layer 115.1. As another example, a portion of integrated circuit chip 125a.2 is sandwiched between a corresponding metal layer 610.2 and a corresponding radiation-absorbing layer 115.2.

[0061] Best-fit plane

[0062] refer to Figure 6 A best-fit plane 620 (e.g., least squares method) is specified for all sensing elements 150 of one of the three radiation-absorbing layers 115.1, 115.2, and 115.3 (e.g., radiation-absorbing layer 115.1) (as shown in the figure). Note that the best-fit plane 620 is perpendicular to the page; therefore, the best-fit plane 620 can be represented by a straight line as shown in the figure.

[0063] Integrated circuit chip overlaps with radiation absorption layer

[0064] In one embodiment, reference Figure 6 For each radiation detector 105 in the image sensor 600, each integrated circuit chip 125 of each radiation detector 105 may at least partially overlap with the radiation absorption layer 115 of each radiation detector 105 in a direction perpendicular to the best-fit plane 620. In other words, a straight line perpendicular to the best-fit plane 620 intersects both the integrated circuit chip 125 and the radiation absorption layer 115.

[0065] For example, for radiation detector 105.1, integrated circuit chip 125a.1 overlaps with radiation absorption layer 115.1 in a direction perpendicular to the best-fit plane 620. As another example, for radiation detector 105.2, integrated circuit chip 125a.2 overlaps with radiation absorption layer 115.2 in a direction perpendicular to the best-fit plane 620.

[0066] Integrated circuit chip protrusion

[0067] In one embodiment, reference Figure 6There can exist at least one plane (e.g., plane 625) that (A) is perpendicular to the best-fit plane 620, (B) intersects all integrated circuit chips 125, and (C) does not intersect any radiation-absorbing layer 115. In other words, structurally, all six integrated circuit chips 125 protrude from the radiation-absorbing layer 115 in the same direction (e.g., downwards, as shown). Note that plane 625 is perpendicular to the page; therefore, plane 625 can be represented by a straight line as shown.

[0068] Input / output connected to the protruding area

[0069] In one embodiment, reference Figure 6 Input / output (I / O) devices (not shown) can electrically connect external circuitry to electrodes (not shown) on the integrated circuit chip 125, such that plane 625 is located between (A) the electrodes and (B) the radiation-absorbing layer 115. In other words, the electrodes for the input / output connections reside on a protruding area (not shown) of the integrated circuit chip 125. Specifically, in Figure 6 In one embodiment, these protruding areas of the integrated circuit chip 125 may be located below the plane 625.

[0070] Metal layer protrusion

[0071] In one embodiment, reference Figure 6 There may be at least one plane (e.g., plane 630) that (A) is perpendicular to the best-fit plane 620, (B) intersects all metal layers 610, and (C) does not intersect any radiation-absorbing layer 115. In other words, structurally, all metal layers 610 protrude from the radiation-absorbing layer 115 in the same direction (e.g., upwards, as shown). Note that plane 630 is perpendicular to the page; therefore, plane 630 can be represented by a straight line as shown.

[0072] The integrated circuit chip and the metal layer protrude in opposite directions.

[0073] In one embodiment, reference Figure 6 Plane 625 can be parallel to plane 630; each point of the radiation-absorbing layer 115 can be located between plane 625 and plane 630 (as shown in the figure). In other words, six integrated circuit chips 125 and three metal layers 610 protrude from the radiation-absorbing layer 115 in two opposite directions. Specifically, the six integrated circuit chips 125 protrude downwards, and the three metal layers 610 protrude upwards (as shown in the figure).

[0074] Thickness of metal layer

[0075] In one embodiment, reference Figure 6The thickness of each metal layer 610, measured in a direction perpendicular to the best-fit plane 620, can be in the range of 50 micrometers to 100 micrometers. For example, the thickness 640 of metal layer 610.1, measured in a direction perpendicular to the best-fit plane 620, is in the range of 50 micrometers to 100 micrometers.

[0076] Thickness of integrated circuit chips

[0077] In one embodiment, reference Figure 6 The thickness of each integrated circuit chip 125, measured in the direction perpendicular to the best-fit plane 620, can be in the range of 10 micrometers to 100 micrometers. For example, the thickness 645 of integrated circuit chip 125a.1, measured in the direction perpendicular to the best-fit plane 620, is in the range of 10 micrometers to 100 micrometers.

[0078] In one embodiment, reference Figure 6 Each straight line segment with its two endpoints on two adjacent radiation-absorbing layers 115 can intersect with the metal layer 610. For example, each straight line segment with its two endpoints on two adjacent radiation-absorbing layers 115.1 and 115.2 intersects with the metal layer 610.2.

[0079] Alternative embodiments of voids in the metal layer of an image sensor

[0080] Figure 7 A viewpoint 650 is schematically shown according to an alternative embodiment. Figure 6 ) Observation Figure 6 The image sensor is 600. Figure 8 The illustration schematically shows an embodiment. Figure 7 A cross-sectional view along line 8-8 of the image sensor 600.

[0081] In one embodiment, reference Figure 7 and Figure 8 In addition to each metal layer 610 including one or more gaps 612 corresponding one-to-one with the integrated circuit chip 125 of the corresponding radiation detector 105, Figure 7 and Figure 8 The image sensor 600 can be similar to Figure 6 The image sensor 600. For example, the metal layer 610.1 may include two gaps 612a.1 and 612b.1 corresponding to the integrated circuit chips 125a.1 and 125b.1, respectively.

[0082] In one embodiment, for each radiation detector 105, the integrated circuit chip 125 of each radiation detector 105 can be respectively located within the gap 612 of the corresponding metal layer 610, thereby creating a straight line (not shown, but which is on the best-fit plane 620) on the best-fit plane 620. Figure 7 The middle is horizontal, in Figure 8 (perpendicular to the page), such that any travel from any point on the integrated circuit chip 125 of each radiation detector 105 in any direction parallel to the straight line will impact the corresponding metal layer 610.

[0083] For example, in radiation detector 105.1, two integrated circuit chips 125a.1 and 125b.1 are located within two gaps 612a.1 and 612b.1 of the corresponding metal layer 610.1, respectively. Note that in Figure 7 In this process, any point on the integrated circuit chips 125a.1 and 125b.1 of the radiation detector 105.1 traveling horizontally (i.e., westward or eastward) will impact the metal layer 610.1.

[0084] Generally, the number of voids 612 in each metal layer 610 can be equal to or less than the number of integrated circuit chips 125 in the corresponding radiation detector 105. The above describes the case where the number of voids 612 in the metal layer 610 is equal to the number of integrated circuit chips 125 in the corresponding radiation detector 105.

[0085] When the number of gaps 612 in the metal layer 610 is less than the number of integrated circuit chips 125 in the corresponding radiation detector 105, at least one of the gaps 612 accommodates a plurality of integrated circuit chips 125. For example, refer to Figure 7 and Figure 8 If gaps 612a.1 and 612b.1 are replaced by a larger gap (not shown), then the larger gap can accommodate two integrated circuit chips 125a.1 and 125b.1. In other words, the two integrated circuit chips 125a.1 and 125b.1 are located within the larger gap.

[0086] In one embodiment, reference Figure 8 The thickness of each integrated circuit chip 125 of the radiation detector 105, measured in the direction perpendicular to the best-fit plane 620, can be less than the thickness of the corresponding metal layer 610, measured in the same direction. For example, the thickness 127 of the integrated circuit chip 125a.1 of the radiation detector 105.1, measured in the direction perpendicular to the best-fit plane 620, is less than the thickness 640 of the corresponding metal layer 610.1, measured in the same direction.

[0087] In one embodiment, reference Figure 8 Each integrated circuit chip 125 of radiation detector 105 is not in direct physical contact with the radiation absorption layer 115 of any other radiation detector 105. For example, integrated circuit chip 125a.1 of radiation detector 105.1 is not in direct physical contact with radiation absorption layer 115.2 or radiation absorption layer 115.3. As another example, integrated circuit chip 125a.2 of radiation detector 105.2 is not in direct physical contact with radiation absorption layer 115.1 or radiation absorption layer 115.3.

[0088] In one embodiment, reference Figure 8 The image sensor 600 is structured such that each straight line segment with two endpoints on two adjacent radiation-absorbing layers 115 intersects with (A) at least one metal layer 610 or (B) at least one void 612. For example, each straight line segment with two endpoints on two adjacent radiation-absorbing layers 115.1 and 115.2 intersects with at least one void 612 of (A) metal layer 610.2 or (B) metal layer 610.2.

[0089] Imaging system

[0090] Figure 9 An imaging system 900 according to an embodiment is schematically illustrated. In one embodiment, the imaging system 900 may include a radiation source 910 and Figure 6 Image sensor 600 (or Figure 7 and Figure 8 Image sensor 600).

[0091] In one embodiment, reference Figure 9 The radiation source 910 and the image sensor 600 can be arranged such that a straight line (not shown) parallel to the best-fit plane 620 intersects both the radiation source 910 and the image sensor 600. This arrangement allows for lateral radiation incident during imaging using the image sensor 600.

[0092] In one embodiment, radiation source 910 may send radiation 912 to object 920 located between radiation source 910 and image sensor 600. In another embodiment, image sensor 600 may capture an image of object 920 based on the interaction between radiation 912 and object 920.

[0093] The interaction between radiation 912 and object 920 can include situations such as: (A) some radiation particles of radiation 912 incident on object 920 are blocked by object 920; (B) some radiation particles of radiation 912 incident on object 920 pass through object 920 without changing their direction; and (C) some radiation particles of radiation 912 incident on object 920 collide with atoms of object 920, thereby changing their direction.

[0094] The term "image" in this application is not limited to the spatial distribution of radiation properties (e.g., intensity). For example, the term "image" may also include the spatial distribution of the density of a substance or element.

[0095] A flowchart summarizing the operation of the imaging system

[0096] Figure 10 An overview according to an embodiment is shown. Figure 9 A flowchart 1000 describes the operation of the imaging system 900. In step 1010, this operation may include sending radiation from a radiation source to an object located between the radiation source and the image sensor. For example, in the above embodiment, referring to... Figure 9 The radiation source 910 sends radiation 912 to the object 920 located between the radiation source 910 and the image sensor 600.

[0097] In step 1020, the operation may include capturing an image of the object using an image sensor based on the interaction between radiation and the object. For example, in the above embodiment, referring to... Figure 9 The image sensor 600 captures images of the object 920 based on the interaction between the radiation 912 and the object 920.

[0098] Discrete regions in the radiation absorption layer

[0099] In one embodiment, reference Figure 5 For image sensor 600 ( Figures 6 to 9 The radiation absorption layer 115 of the radiation detector 105 in the figure can be integral (as shown). Alternatively, refer to Figure 11A (Top view) and Figure 11B (Perspective view), for image sensor 600 ( Figures 6 to 9 The radiation absorption layer 115 of the radiation detector 105 in the image may include a plurality of discrete radiation absorption regions (e.g., two discrete radiation absorption regions 115a and 115b as shown in the figure). In one embodiment, Figure 11A and Figure 11B The radiation detector 105 may include an integrated circuit chip 125 for processing electrical signals generated in discrete radiation absorption regions 115a and 115b. Note that... Figure 11A and Figure 11B The integrated circuit chip 125 protrudes from the discrete radiation absorption regions 115a and 115b in a manner similar to Figure 5 The integrated circuit chips 125a and 125b protrude from the radiation absorption layer 115 in such a way.

[0100] While various aspects and embodiments have been disclosed herein, other aspects and embodiments will be apparent to those skilled in the art. The various aspects and embodiments disclosed herein are for illustrative purposes and are not intended to be limiting; the true scope and spirit are indicated by the appended claims.

Claims

1. A system comprising an image sensor, the image sensor comprising: M metal layers (metal layer(i), i = 1, ..., M), where M is an integer greater than 1; and M radiation detectors (radiation detector(i), i = 1, ..., M), For each value of i, the radiation detector (i) includes a radiation absorption layer (i) and an integrated circuit chip (i, j) configured to process electrical signals generated in the radiation absorption layer (i), j = 1, ..., Ni, where Ni, i = 1, ..., M are positive integers. The M metal layers and the radiation absorption layer (i), i = 1, ..., M, together form a stacked layer. Among the M radiation detectors, all sensing elements of one of the radiation detectors have an optimal fitting plane. Wherein, for each value of i, each of the integrated circuit chips (i, j), j = 1, ..., Ni, at least partially overlaps the radiation absorption layer (i) in a direction perpendicular to the best-fit plane, and There exists a first plane perpendicular to the best-fit plane, which intersects all the integrated circuit chips (i, j), i = 1, ..., M and j = 1, ..., Ni, and does not intersect any of the radiation absorption layers (i), i = 1, ..., M.

2. The system according to claim 1, wherein, The stack comprises 2×M layers.

3. The system according to claim 1, wherein, The M metal layers contain metals with an atomic number of at least 26.

4. The system according to claim 3, wherein, The metal is tungsten, platinum, or gold.

5. The system according to claim 1, wherein, The M metal layers and the radiation absorbing layer (i), i = 1, ..., M, are arranged alternately in the stack.

6. The system according to claim 1, wherein, There exists a second plane perpendicular to the best-fit plane, which intersects all of the M metal layers and does not intersect any of the radiation-absorbing layers (i), i = 1, ..., M.

7. The system according to claim 6, in, The first plane is parallel to the second plane, and In this context, each point of the radiation absorption layer (i), i = 1, ..., M, is located between the first plane and the second plane.

8. The system according to claim 1, wherein, The thickness of each of the M metal layers, measured in a direction perpendicular to the best-fit plane, is in the range of 50 micrometers to 100 micrometers.

9. The system according to claim 1, wherein, Each of the integrated circuit chips (i, j), i = 1, ..., M and j = 1, ..., Ni, includes a dedicated integrated circuit.

10. The system according to claim 1, wherein, The M metal layers are configured to block and absorb X-rays.

11. The system according to claim 1, in, The input / output device electrically connects external circuitry to the electrodes on the integrated circuit chip (i, j), where i = 1, ..., M and j = 1, ..., Ni. The first plane is located between the electrode (A) and the radiation absorption layer (i) (B), where i = 1, ..., M.

12. The system according to claim 1, wherein, For each value of i, the radiation-absorbing layer (i) comprises a plurality of discrete radiation-absorbing regions.

13. The system according to claim 12, wherein, Ni, i=1,..., M are all 1.

14. The system according to claim 1, wherein, The radiation-absorbing layer (i), i = 1, ..., M, contains GaAs, CdTe, or CdZnTe.

15. The system according to claim 1, wherein, The thickness of each of the integrated circuit chips (i, j), i = 1, ..., M and j = 1, ..., Ni, measured in a direction perpendicular to the best-fit plane, is in the range of 10 micrometers to 100 micrometers.

16. The system according to claim 1, wherein, For each value of i and each value of j, a portion of the integrated circuit chip (i, j) is sandwiched between the metal layer (i) and the radiation-absorbing layer (i).

17. The system according to claim 1, in, For each value of i, the metal layer (i) comprises Pi voids, where Pi is a positive integer not greater than Ni, and Wherein, for each value of i, the integrated circuit chip (i, j), j = 1, ..., Ni is within the Pi gaps, so that there exists a straight line on the best-fit plane, such that any travel from any point of the integrated circuit chip (i, j), j = 1, ..., Ni in any direction parallel to the straight line will impact the metal layer (i).

18. The system according to claim 17, wherein, For every value of i, Ni > Pi.

19. The system according to claim 17, in, For each value of i, Ni = Pi, and For each value of i, the integrated circuit chip (i, j), j = 1, ..., Ni is located in the Pi gaps respectively.

20. The system according to claim 19, wherein, For each value of i, the thickness of each integrated circuit chip (i, j), j = 1, ..., Ni of the radiation detector (i) measured in the direction perpendicular to the best-fit plane is less than the thickness of the metal layer (i) measured in the direction perpendicular to the best-fit plane.

21. The system according to claim 19, wherein, For each value of i, each integrated circuit chip (i, j), j = 1, ..., Ni of the radiation detector (i) does not have direct physical contact with the radiation absorption layer of any of the other radiation detectors among the M radiation detectors.

22. The system according to claim 19, wherein, Each straight line segment on two adjacent radiation-absorbing layers (i), i = 1, ..., M, with two endpoints intersects with (A) at least one metal layer of the M metal layers or (B) at least one void in one of the M metal layers.

23. The system according to claim 1, wherein, Each straight line segment on two adjacent radiation-absorbing layers (i), i = 1, ..., M, intersects one of the M metal layers.

24. The system according to claim 1 further includes a radiation source. in, A straight line parallel to the best-fit plane intersects both the radiation source and the image sensor, and Wherein, the first plane is not between the radiation source and the radiation absorption layer (i), i = 1, ..., M.

25. A method of using the system according to claim 24, comprising: Radiation is emitted from the radiation source toward an object located between the radiation source and the image sensor; as well as Based on the interaction between the radiation and the object, an image of the object is captured using the image sensor.

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