Side-incident image sensor with protruding integrated circuit chip

Abstract

A system having 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 absorbing layer (i) and an integrated circuit chip (i, j), j = 1,..., Ni. Ni, i = 1,..., and M is a positive integer. The plurality of metal layers and the plurality of radiation absorbing layers together form a layer stack. All sensing elements of one of the radiation detectors have a best fit plane. Each of the integrated circuit chips (i, j), j = 1,..., Ni at least partially overlaps the radiation absorbing layer (i) in a direction perpendicular to the best fit plane. There is a first plane perpendicular to the best fit plane that intersects all of the integrated circuit chips and that does not intersect any of the plurality of radiation absorbing layers.

Description

[Background technology]

[0001] A radiation detector is a device that measures a property of radiation. Examples of such properties may include the spatial distribution of the intensity, phase, polarization of the radiation. The radiation measured by the radiation detector may be radiation that has passed through an object. The radiation measured by the radiation detector may be electromagnetic radiation, such as infrared light, visible light, ultraviolet light, X-rays, or gamma rays. The radiation may be of 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] Disclosed herein is a system, comprising an image sensor, the image sensor comprising: M metal layers (metal layer (i), i=1, ..., M) and M radiation detectors (radiation detector (i), i=1, ..., M), wherein M is an integer greater than 1. For each value of i, the radiation detector (i) comprises a radiation absorption layer (i) and an integrated circuit chip (i, j), j=1, ..., Ni configured to process an electrical signal 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. There is a best-fit plane for all sensing elements of one radiation detector among the M radiation detectors. For each value of i, each of the integrated circuit chips (i, j), j=1, ..., Ni at least partially overlaps with the radiation absorption layer (i) in a direction perpendicular to the best-fit plane. There is a first plane perpendicular to the best fit plane, which intersects all of the integrated circuit chips (i, j), i=1,...,M and j=1,...,Ni, and does not intersect any radiation absorbing layer among the radiation absorbing layers (i), i=1,...,M.

[0003] In one aspect, the stack comprises 2 x M layers.

[0004] In one aspect, the M metal layers comprise a metal having an atomic number of at least 26.

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

[0006] In one aspect, the M metal layers and the radiation absorbing layers (i), i=1, ..., M are arranged in an alternating manner in the stack.

[0007] In one aspect, there is a second plane perpendicular to the best fit plane, the second plane intersecting all of the M metal layers and not intersecting any of the radiation absorbing layers (i), i=1, ...,M.

[0008] In one aspect, 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] In one aspect, each of the M metal layers has a thickness in a range of 50 microns to 100 microns measured in a direction perpendicular to the best fit plane.

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

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

[0012] On the one hand, the input / output device electrically connects the external circuit to the 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 absorbing layer (i), i=1,...,M.

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

[0014] In one aspect, Ni,i=1, ..., M are all 1.

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

[0016] In one aspect, 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 microns to 100 microns.

[0017] In one aspect, 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 the 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, so that there is a straight line on the best fit plane, so that any point on the integrated circuit chip (i, j), j=1, ..., Ni moving in any direction parallel to the straight line will hit the metal layer (i).

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

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

[0021] On the 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 a direction perpendicular to the best fit plane is less than the thickness of the metal layer (i) measured in a direction perpendicular to the best fit plane.

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

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

[0024] In one aspect, each straight line segment having two endpoints on two adjacent radiation absorbing layers in the radiation absorbing layer (i), i=1, ..., M intersects one of the M metal layers.

[0025] In one aspect, the system further comprises 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] A method for using the above system is disclosed herein, comprising sending 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.

Brief Description of the Drawings

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

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

[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 schematically shown.

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

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

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

[0035] Fig.10 A flow chart outlining the operation of an imaging system according to an embodiment is shown.

[0036] Fig.11A and Fig. 11B An alternative embodiment is shown. Figure 5 radiation detector. [Specific implementation method]

[0037] Radiation Detectors

[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). The array may be a rectangular array (e.g. Figure 1 as shown), a honeycomb array, a hexagonal array, or any other suitable array. Figure 1 The array of pixels 150 in the example of FIG. 4 has 4 rows and 7 columns; however, in general, the array of pixels 150 may have any number of rows and any number of columns.

[0039] Each pixel 150 can be configured to detect radiation from a radiation source (not shown) incident thereon, and can be configured to measure the characteristics of the radiation (e.g., the energy, wavelength, and frequency of the particles). Radiation may include radiation 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 radiation particles incident thereon and whose energy falls into multiple energy bins over a period of time. All pixels 150 can be configured to count the number of radiation particles incident thereon and falling into multiple energy bins over the same period of time. When the incident radiation particles have similar energies, the pixel 150 can be configured only to count the number of radiation particles incident thereon over a period of time without measuring the energy of a single radiation particle.

[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 radiation particle into a digital signal, or to digitize an analog signal representing the total energy of multiple incident radiation particles into a digital signal. Pixels 150 may be configured to operate in parallel. For example, when one pixel 150 measures an incident radiation particle, another pixel 150 may be waiting for the radiation particle to arrive. Pixels 150 may not necessarily be individually addressable.

[0041] The radiation detector 100 described herein may have 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 nondestructive testing, X-ray weld inspection, X-ray digital subtraction angiography, etc. It may be appropriate to use the radiation detector 100 instead of a photographic plate, photographic film, a photo-stimulated phosphor plate (PSP plate), an X-ray image intensifier, a scintillator, or other semiconductor X-ray detector.

[0042] Figure 2 Schematically shows a Figure 1 2-2. Specifically, the radiation detector 100 may include a radiation absorbing layer 110 and an electronic circuit layer 120 (which may include one or more ASICs or application specific integrated circuits) for processing and analyzing 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 a combination thereof. The semiconductor material may have a high mass attenuation coefficient for the radiation of interest.

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

[0044] The electronic circuit layer 120 may include an electronic system 121 suitable for processing or interpreting signals generated by radiation incident on the radiation absorption layer 110. The electronic system 121 may include analog circuits such as filter networks, amplifiers, integrators, and comparators, or digital circuits such as microprocessors and memories. The electronic system 121 may include one or more analog-to-digital converters. The electronic system 121 may include components shared by multiple pixels 150 or components dedicated to a single pixel 150. For example, the electronic system 121 may include an amplifier dedicated to each pixel 150 and a microprocessor shared between all pixels 150. The electronic system 121 may be electrically connected to the pixel 150 through the through hole 131. The space between the through holes may be filled with a filling material 130, which may increase the mechanical stability of the connection between the electronic circuit layer 120 and the radiation absorption layer 110. Other bonding techniques may connect the electronic system 121 to the pixel 150 without using the through hole 131.

[0045] When radiation from a radiation source (not shown) strikes the radiation absorbing layer 110 including a diode, the radiation particles may be absorbed and generate one or more carriers (e.g., electrons, holes) through a variety of mechanisms. The carriers may drift to one of the electrodes of the diodes under an electric field. The electric field may be an external electric field. The electrical contact 119B may include a plurality of discrete portions, each of which is in electrical contact with the discrete region 114. The term "electrical contact" may be used interchangeably with the term "electrode". In one embodiment, the carriers may drift in a plurality of directions, and the carriers generated by a single radiation particle are not substantially shared by two different discrete regions 114 (here "substantially not shared by..." means that less than 2%, less than 0.5%, less than 0.1%, or less than 0.01% of these carriers flow to a discrete region different from the discrete region to which the remaining carriers flow in the plurality of discrete regions 114). The charge carriers generated by radiation particles incident around the footprint of one of the discrete regions 114 are substantially not shared by another of the discrete regions 114. A pixel 150 associated with a discrete region 114 may be an area around the 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 radiation particles incident therein flow toward the discrete region 114. That is, less than 2%, less than 1%, less than 0.1%, or less than 0.01% of the charge carriers flow out of the pixel 150.

[0046] Figure 4 Schematically shows a Figure 1 Detailed cross-sectional view of radiation detector 100 along line 2-2. More specifically, radiation absorbing layer 110 may include resistors of semiconductor materials such as silicon, germanium, GaAs, CdTe, CdZnTe, or combinations thereof, but not diodes. The semiconductor material may have a high mass 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 is provided.

[0047] When radiation strikes the radiation absorbing layer 110, which includes a resistor but does not include a diode, it can be absorbed and generate one or more carriers through a variety of mechanisms. The radiation particles can generate 10 to 100,000 carriers. The carriers can drift to the electrical contacts 119A and 119B under an electric field. The electric field can be an external electric field. The electrical contact 119B may include multiple discrete portions. In one embodiment, the carriers can drift in multiple directions, and the carriers generated by a single radiation particle are substantially not shared by two different discrete portions of the electrical contact 119B (here "substantially not shared by..." means that less than 2%, less than 0.5%, less than 0.1% or less than 0.01% of these carriers flow to a discrete portion different from the discrete portion to which the remaining carriers flow). The carriers generated by the radiation particles incident on the occupied space of one of the discrete portions of the electrical contact 119B are substantially not shared by another discrete portion of the discrete portions of the electrical contact 119B. A pixel 150 associated with a discrete portion of electrical contact 119B may be a region around the 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 radiation particles incident therein flow toward the discrete portion of 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 the discrete portion of electrical contact 119B.

[0048] Radiation detector with protruding integrated circuit chip

[0049] Figure 5 A perspective view of a radiation detector 105 according to an embodiment is schematically shown. In one embodiment, the radiation detector 105 may include a radiation absorbing layer 115 and one or more integrated circuit chips 125 (eg, 2 integrated circuit chips 125a and 125b as shown).

[0050] In one embodiment, the radiation detector 105 may be similar to Figures 1 to 4 The radiation detector 100 is configured such that (A) the radiation absorbing layer 115 of the radiation detector 105 is similar in structure and function to the radiation absorbing 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 chips 125 of the radiation detector 105 may be configured to process the electrical signals generated in the radiation absorbing 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 The radiation detectors 105 may include radiation absorbing 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, but Figure 6 Only one of the two integrated circuit chips 125 is shown in FIG. 1 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, but Figure 6 Only integrated circuit chip 125a.1 is shown in FIG. 1 because integrated circuit chip 125b.1 is hidden from view (integrated circuit chip 125b.1 is behind integrated circuit chip 125a.1). Figure 7 Integrated circuit chip 125b.1 can be seen in FIG.

[0055] Layer stacking

[0056] In one embodiment, reference Figure 6 The image sensor 600 may also include a plurality of metal layers 610 (e.g., three metal layers 610.1, 610.2, and 610.3 as shown) corresponding one to one with the radiation detectors 105. 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 may be arranged in an alternating manner in the stack (as shown). "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 (eg, tungsten, platinum, and gold) having an atomic number of at least 26. In one embodiment, the metal layer 610 may block and absorb X-rays.

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

[0060] In one embodiment, reference Figure 6 , each integrated circuit chip 125 of 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. For 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 radiation absorbing layer (e.g., radiation absorbing layer 115.1) among the three radiation absorbing layers 115.1, 115.2, and 115.3 (e.g., radiation absorbing layer 115.1) (as shown). 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.

[0063] Integrated circuit chip overlaps with radiation absorbing 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 radiation absorbing layer 115.1 in a direction perpendicular to best fit plane 620. For another example, for radiation detector 105.2, integrated circuit chip 125a.2 overlaps radiation absorbing layer 115.2 in a direction perpendicular to best fit plane 620.

[0066] Integrated circuit chip protrusion

[0067] In one embodiment, reference Figure 6, there may be at least one such plane (e.g., plane 625) that is (A) 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., downward 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 connections to highlighted areas

[0069] In one embodiment, reference Figure 6 , an input / output (I / O) device (not shown) can electrically connect an external circuit to an electrode (not shown) on the integrated circuit chip 125 such that the plane 625 is located between (A) the electrode and (B) the radiation absorbing layer 115. In other words, the electrode for the input / output connection resides on a protruding area (not shown) of the integrated circuit chip 125. Specifically, in Figure 6 In one embodiment, these protruding regions 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 such plane (e.g., plane 630) that is (A) 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., upward 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 may be parallel to plane 630; each point of radiation absorbing layer 115 may 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 radiation absorbing layer 115 in two opposite directions. Specifically, six integrated circuit chips 125 protrude downward, and three metal layers 610 protrude upward (as shown in the figure).

[0074] Thickness of metal layer

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

[0076] Thickness of IC chip

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

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

[0079] Image Sensor - Alternative Embodiments of Voids in Metal Layers

[0080] Figure 7 Schematically illustrates a view from a viewpoint 650 ( Figure 6 )Observation Figure 6 An image sensor 600 is provided. Figure 8 Schematically shows a Figure 7 A cross-sectional view of image sensor 600 along line 8 - 8 .

[0081] In one embodiment, reference Figure 7 and Figure 8 In addition to each metal layer 610 including one or more voids 612 corresponding one-to-one to the integrated circuit chip 125 of the corresponding radiation detector 105, Figure 7 and Figure 8 The image sensor 600 may be similar to Figure 6 For example, metal layer 610.1 may include two voids 612a.1 and 612b.1 corresponding to 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 may be located in the gap 612 of the corresponding metal layer 610, so that a straight line exists on the best fit plane 620 (not shown, but the straight line is Figure 7 is horizontal, Figure 8 , perpendicular to the page) so that any direction parallel to the straight line from any point of the integrated circuit chip 125 of each radiation detector 105 will hit the corresponding metal layer 610.

[0083] For example, for the radiation detector 105.1, two integrated circuit chips 125a.1 and 125b.1 are respectively located in two gaps 612a.1 and 612b.1 of the corresponding metal layer 610.1. Figure 7 , traveling horizontally (ie, west or east) from any point of the integrated circuit chips 125a.1 and 125b.1 of the radiation detector 105.1 will hit the metal layer 610.1.

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

[0085] In the case where the number of voids 612 of the metal layer 610 is less than the number of integrated circuit chips 125 of the corresponding radiation detector 105, at least one of the plurality of voids 612 accommodates a plurality of integrated circuit chips 125. Figure 7 and Figure 8 If the gaps 612a.1 and 612b.1 are replaced by a larger gap (not shown), 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 in 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 a direction perpendicular to the best fit plane 620 may be less than the thickness of the corresponding metal layer 610 measured in a direction perpendicular to the best fit plane 620. For example, the thickness 127 of the integrated circuit chip 125a.1 of the radiation detector 105.1 measured in a direction perpendicular to the best fit plane 620 is less than the thickness 640 of the corresponding metal layer 610.1 measured in a direction perpendicular to the best fit plane 620.

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

[0088] In one embodiment, reference Figure 8 The structure of the image sensor 600 can make each straight line segment whose two endpoints are respectively on two adjacent radiation absorption layers 115 intersect with (A) at least one metal layer 610 or (B) at least one gap 612. For example, each straight line segment whose two endpoints are respectively on two adjacent radiation absorption layers 115.1 and 115.2 intersects with (A) metal layer 610.2 or (B) at least one gap 612 of metal layer 610.2.

[0089] Imaging System

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

[0091] In one embodiment, reference Fig. 9 , radiation source 910 and image sensor 600 may be arranged such that a straight line (not shown) parallel to best fit plane 620 intersects both radiation source 910 and image sensor 600. This arrangement allows for side radiation incidence during imaging using image sensor 600.

[0092] In one embodiment, radiation source 910 may transmit radiation 912 to object 920 located between radiation source 910 and image sensor 600. In one 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 may include situations such as the following: (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 directions, and (C) some radiation particles of radiation 912 incident on object 920 collide with atoms of object 920, thereby changing their directions.

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

[0095] Flowchart outlining the operation of the imaging system

[0096] Fig.10 shows a summary according to an embodiment Fig. 9 1000 of the operation of the imaging system 900. In step 1010, the 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, reference Fig. 9 , radiation source 910 sends radiation 912 to an object 920 located between radiation source 910 and 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 the radiation and the object. Fig. 9 , the image sensor 600 captures an image of the object 920 based on the interaction between the radiation 912 and the object 920.

[0098] Discrete regions in the radiation absorbing layer

[0099] In one embodiment, reference Figure 5 , for image sensor 600( Figures 6 to 9 ) the radiation absorbing layer 115 of the radiation detector 105 may be integral (as shown). Alternatively, referring to Fig.11A (top view) and Fig. 11B (perspective view), for image sensor 600 ( Figures 6 to 9 ) may include a plurality of discrete radiation absorption regions (eg, two discrete radiation absorption regions 115a and 115b as shown). In one embodiment, Fig.11A and Fig. 11B The radiation detector 105 may include an integrated circuit chip 125 for processing the electrical signals generated in the discrete radiation absorption regions 115a and 115b. Fig.11A and Fig. 11B The integrated circuit chip 125 protrudes from the discrete radiation absorbing regions 115a and 115b in a manner similar to Figure 5 The integrated circuit chips 125 a and 125 b protrude from the radiation absorbing layer 115 .

[0100] Although 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 purposes of illustration and are not intended to be limiting, with the true scope and spirit being 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), wherein, for each value of i, the radiation detector (i) comprises a radiation absorbing layer (i) and an integrated circuit chip (i, j) configured to process an electrical signal generated in the radiation absorbing layer (i), j=1, ..., Ni, wherein Ni, i=1, ..., M are positive integers, wherein the M metal layers and the radiation absorbing layer (i), i=1, ..., M together form a layer stack, wherein a best-fit plane exists for all sensing elements of one radiation detector among the M radiation detectors, wherein, for each value of i, each of the integrated circuit chips (i, j), j=1, ..., Ni, at least partially overlaps the radiation absorbing layer (i) in a direction perpendicular to the best fit plane, and There is a first plane perpendicular to the best fit plane, which intersects with all the integrated circuit chips (i, j), i=1,...,M and j=1,...,Ni, and does not intersect with any radiation absorption layer among 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 include a metal having 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 layers (i), i=1, ..., M are arranged in an alternating manner in the stack.

6. The system according to claim 1, wherein: There is a second plane perpendicular to the best fit plane, the second plane intersecting all of the M metal layers and not intersecting 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 Wherein, each point of the radiation absorbing layer (i), i=1, ..., M is located between the first plane and the second plane.

8. The system according to claim 1, wherein: A thickness of each of the M metal layers measured in a direction perpendicular to the best fit plane is in a 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 the external circuit to the electrodes on the integrated circuit chip (i, j), i=1, ..., M and j=1, ..., Ni, and Wherein, the first plane is between (A) the electrode and (B) the radiation absorbing layer (i), i=1,...,M.

12. The system of 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 of claim 1, wherein: The radiation absorbing layers (i), i=1, ..., M comprise GaAs, CdTe or CdZnTe.

15. The system of 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 of 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) includes 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 is a straight line on the best fit plane, so that any point of the integrated circuit chip (i, j), j=1, ..., Ni moving in any direction parallel to the straight line will hit the metal layer (i).

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

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

20. The system of 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 a direction perpendicular to the best fit plane is less than the thickness of the metal layer (i) measured in a direction perpendicular to the best fit plane.

21. The system of claim 19, wherein: For each value of i, each of the integrated circuit chips (i, j), j=1, ..., Ni of the radiation detector (i) is not in direct physical contact with the radiation absorbing layer of any other radiation detector among the M radiation detectors.

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

23. The system of claim 1, wherein: Each straight line segment having two endpoints on two adjacent radiation absorbing layers in the radiation absorbing layer (i), i=1, ..., M intersects with one of the M metal layers.

24. The system of claim 1, further comprising a radiation source, in, 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.

25. A method of using the system according to claim 24, comprising: sending radiation from the radiation source toward an object 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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