High-density infrared photoelectric focal plane array sensor

Abstract

The utility model provides a high-density infrared photoelectric focal plane array sensor, which comprises a sensitive element chip and a through hole element which are connected in an overlapped manner, the sensitive element chip comprises a first substrate, a plurality of sensitive elements arranged on the first substrate and a plurality of pairs of electrodes arranged at the two ends of each sensitive element, the through hole element comprises a second substrate, a plurality of pairs of through holes formed in the second substrate and metal filling columns arranged in the through holes, each pair of electrodes corresponds to one pair of through holes in a one-to-one mode, and the ends of the metal filling columns are connected with the electrodes in a welded mode. According to the utility model, the sensitive element chip and the through hole element are respectively manufactured, and then the electrode of the sensitive element chip corresponds to the through hole and is connected with the through hole through a flip-chip bonding method, so that the vertical interconnection between the sensitive element and the through hole is realized; according to the utility model, the structure is simple, not only is the preparation process flow of the area array sensitive element simplified, but also small-size and high-density focal plane array integration is realized.

Description

Technical Field

[0001] The utility model relates to the technical field of infrared sensors, in particular to a high-density infrared optoelectronic focal plane array sensor. Background Art

[0002] Since the 21st century, infrared imaging technology has made great progress. The development speed of infrared imaging technology mainly depends on the progress made in infrared detector technology. Infrared detector technology has gone through the stages of single element, linear array, staring array, and is currently developing towards the direction of high performance, high reliability, further miniaturization, uncooled, and dual-use technology for both military and civilian applications with ultra-high density integration of focal plane. Currently, the relatively mature focal plane array detectors studied are mainly focal plane chips prepared from materials such as InGaSb, HgCdTe, QWIP, and InAs / GaSb type-II superlattice. However, they all require liquid nitrogen cooling or lower temperatures to obtain high infrared detection performance. Therefore, the research and development of uncooled infrared focal plane arrays will promote the expansion of infrared thermal imaging technology from long-term mainly military purposes to broad civilian fields, such as industrial monitoring and temperature measurement, law enforcement and drug suppression, security and prevention, medical and health, remote sensing, early fault diagnosis and maintenance of equipment, and night vision enhancement viewers for ship drivers, etc.

[0003] To improve the resolution of system imaging and the target recognition ability, significantly increasing the integration degree of the focal plane infrared detection pixels of the system is an important way. Each company and manufacturer is trying its best to increase the number of pixels of the focal plane array and develop large or extra-large infrared focal plane arrays of various formats. IV-VI group semiconductor compounds (such as PbS, PbSe, and PbTe) have characteristics such as direct bandgap and narrow bandgap width. PbSe photoconductive detectors can obtain good infrared detection ability at room temperature, so they are very suitable for making focal plane infrared detectors that work at room temperature.

[0004] The Chinese invention application with the publication date of September 5, 2023, and the publication number of CN 116699566 A discloses an infrared sensor, an infrared focal plane array, a display panel, and a display device. The infrared sensor includes a substrate, a sensor device, and a readout circuit. The substrate includes a first area and a second area. The sensor device is located in the first area, and the readout circuit is located in the second area. The sensor device includes a first electrode, a second electrode, and a thermal-sensitive layer connected between the first electrode and the second electrode. The thermal-sensitive layer is configured to change its resistance when receiving infrared light. The readout circuit includes a switch terminal, an input terminal, and an output terminal. The input terminal is electrically connected to the second electrode. The readout circuit is configured to: under the control of the signal of the switch terminal, output an electrical signal corresponding to the infrared light at the output terminal. However, the structure of the infrared sensor in this application is complex, and the preparation process is also complex. Summary of the Invention

[0005] In view of the above technical problems, the utility model provides a high-density infrared optoelectronic focal plane array sensor to solve the problems of complex structure and complex manufacturing process of the focal plane array sensor in the prior art.

[0006] In order to achieve the above object, the technical solution of the utility model is realized as follows:

[0007] A high-density infrared optoelectronic focal plane array sensor includes a stacked and connected sensitive element chip and a via element. The sensitive element chip includes a first substrate, a plurality of sensitive elements disposed on the first substrate, and multiple pairs of electrodes disposed at both ends of each sensitive element. The via element includes a second substrate, multiple pairs of vias disposed on the second substrate, and metal filling columns disposed in the vias. Each pair of electrodes corresponds to a pair of vias one by one, and the end of the metal filling column is welded to the electrode.

[0008] Further, the metal filling column is connected to the electrode through a solder joint.

[0009] Further, the second substrate is a glass substrate.

[0010] Further, leads connected to each via and second electrodes connected to the leads are provided on the second substrate.

[0011] Further, the leads include multiple first leads arranged at intervals and multiple second leads arranged at intervals. One of each pair of vias is connected to the first lead, and the other via is connected to the second lead.

[0012] Further, the vias are arranged in a rectangular array, the first leads and the second leads are arranged vertically and horizontally. Each pair of vias includes a left via and a right via. Each column of left vias is connected to a first lead, and each right via in each column of right vias is respectively connected to a second lead.

[0013] Further, each first lead includes a first main lead arranged longitudinally and multiple first branch leads connected to the first main lead. The first branch leads are arranged horizontally, and the multiple first branch leads are respectively connected to the left vias in the corresponding column; a second electrode is connected to the end of each first main lead.

[0014] Further, each second lead includes a second main lead arranged horizontally and multiple second branch leads connected to the second main lead. The second branch leads are arranged longitudinally, and the multiple second branch leads are respectively connected to the right vias in the corresponding row; a second electrode is connected to the end of each second main lead.

[0015] Further, the side view projection of the solder joint is a semi-circular structure, and the straight side of the semi-circular structure faces the sensitive element chip and is connected to the end of the metal filling column.

[0016] Further, one end of the metal-filled column away from the electrode protrudes from the surface of the second substrate.

[0017] Advantages of the present utility model:

[0018] 1. In the present utility model, the sensitive element chip and the via element are fabricated separately, and then the electrodes of the sensitive element chip are aligned with the vias and connected by flip-chip bonding to achieve vertical interconnection between the sensitive element and the via.

[0019] 2. The structure of the present utility model is simple, which not only simplifies the manufacturing process of the area array sensitive element, but also realizes the integration of a small-size high-density focal plane array. Description of the Drawings

[0020] In order to more clearly illustrate the technical solutions in the embodiments of the present utility model or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the following drawings are only some embodiments of the present utility model, and for those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0021] Figure 1 It is a schematic structural diagram of the sensitive element chip of the present utility model.

[0022] Figure 2 It is a schematic structural diagram of the via element of the present utility model.

[0023] Figure 3 It is a schematic cross-sectional structural diagram of the present utility model.

[0024] In the figure: 1. Substrate, 2. Sensitive element, 3. Electrode, 4. Via, 5. First lead, 6. Second lead, 7. Second substrate, 8. Second electrode, 9. Metal-filled column, 10. Solder joint. Detailed Embodiments

[0025] The following will clearly and completely describe the technical solutions in the embodiments of the present utility model with reference to the drawings in the embodiments of the present utility model. Obviously, the described embodiments are only some embodiments of the present utility model, rather than all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative efforts belong to the scope of protection of the present utility model.

[0026] As Figures 1 to 3 shown, a high-density infrared optoelectronic focal plane array sensor described in Embodiment 1 of the present utility model includes a sensitive element chip and a via element connected in an overlapping manner. In this embodiment, as Figure 1As shown, the sensitive element chip is disposed on the upper side of the through-hole element. The sensitive element chip includes a first substrate 1, a plurality of sensitive elements 2 disposed on the first substrate 1, and multiple pairs of electrodes 3. The plurality of sensitive elements 2 are arranged in an array, and each pair of electrodes 3 is disposed at both ends of each sensitive element 2. The through-hole element includes a second substrate 7, multiple pairs of through-holes 4 disposed on the second substrate 7, and metal filling columns 9 filled in the through-holes 4. Each pair of electrodes 3 corresponds to a pair of through-holes 4 one by one, that is, every two through-holes form a pair. The two through-holes in this pair of through-holes respectively correspond to the two electrodes in a pair of electrodes, so that the metal filling columns 9 of each pair of through-holes 4 can correspond to each pair of electrodes 3, and the lower end portions of the metal filling columns 9 are welded to the electrodes 3. Among them, the metal filling columns 9 are connected to the electrodes 3 through solder joints 10.

[0027] Embodiment 2, which is different from Embodiment 1 in that, as Figure 2 shown, the second substrate 7 is a glass substrate. The second substrate 7 is provided with leads connected to each through-hole 4 and second electrodes 8 connected to the leads.

[0028] Furthermore, as Figure 2 shown, the leads include a plurality of first leads 5 arranged at intervals and a plurality of second leads 6 arranged at intervals. One of the through-holes 4 in each pair of through-holes 4 is connected to the first lead 5, and the other through-hole 4 is connected to the second lead 6.

[0029] Specifically, the through-holes 4 are arranged in a rectangular array. Each pair of through-holes 4 includes a left through-hole and a right through-hole. The first leads 5 and the second leads 6 are arranged vertically and horizontally in the gaps between the through-holes. Among them, the first leads 5 are arranged vertically, and the second leads 6 are arranged horizontally. Each column of left through-holes is connected to one first lead 5, that is, each column of left through-holes corresponds to one first lead 5, and each through-hole in this column of left through-holes is connected to this first lead 5. Each right through-hole in each column of right through-holes is respectively connected to one second lead 6, that is, each through-hole in this column of right through-holes is connected to one second lead 6; and the second leads 6 are arranged horizontally in rows, and the right through-holes in the same row correspond to one second lead 6.

[0030] Furthermore, each first lead 5 includes a first main lead arranged vertically and a plurality of first branch leads connected to the first main lead. The first branch leads are arranged horizontally, and the plurality of first branch leads are respectively connected to the left through-holes in the corresponding column; a second electrode 8 is connected to the end of each first main lead.

[0031] Furthermore, each second lead 6 includes a second main lead arranged horizontally and a plurality of second branch leads connected to the second main lead. The second branch leads are arranged vertically, and the plurality of second branch leads are respectively connected to the right through-holes in the corresponding row; a second electrode 8 is connected to the end of each second main lead.

[0032] Example 3, which is different from Example 1 in that, as Figure 3 shown, the side view projection of the solder joint 10 is a semi-circular structure, and the straight side of the semi-circular structure faces the sensitive element chip, that is, the straight side is upward and horizontally arranged. That is, the planar side of the solder joint 10 faces upward, and this upper side plane is connected to the end of the metal filling column 9, and the lowest point of the arc surface of the semi-circular structure is connected to the electrode 3.

[0033] Further, the end of the metal filling column 9 far from the electrode 3, that is, the upper end, protrudes from the surface of the second substrate 7.

[0034] The preparation process of the present utility model is as follows:

[0035] On the cleaned substrate 1, a lead selenide thin film is prepared by methods such as chemical bath deposition, physical / chemical vapor deposition, sputtering deposition, etc., and the sensitive element is sensitized at high temperature; then an ultraviolet photolithography process is carried out on the obtained lead selenide thin film substrate to engrave the sensitive element area, and the remaining lead selenide thin film is removed by wet or dry etching to obtain the sensitive element 2. Then, an electrode pattern is over-etched on the above-mentioned substrate 1 by photolithography technology, and electrode materials are plated by methods such as evaporation plating, magnetron sputtering, electron beam evaporation, etc., and the electrode materials include one or two of gold, chromium, nickel, and titanium; then the photoresist is removed by the lift-off technique, leaving the electrode layer, that is, the electrode 3. Then, a passivation layer material is plated by methods such as evaporation plating, magnetron sputtering, electron beam evaporation, etc., and the passivation layer materials include silicon dioxide, aluminum oxide, polytetrafluoroethylene, etc.; then the photoresist is removed by the lift-off technique, thereby obtaining a focal plane type optoelectronic thin film.

[0036] The glass substrate 7 is cleaned, and through processes such as laser ablation, plasma etching, sandblasting, wet etching, etc., through holes 4 are prepared, and then wiring preparation is carried out on the front surface. The lead area is defined by photolithography, leads are plated by methods such as evaporation plating, magnetron sputtering, electron beam evaporation, etc., and then the photoresist is removed by the lift-off technique to lay the first lead 5. The lead protection area is defined by photolithography, an insulating layer is plated by physical / chemical vapor deposition, the photoresist is removed by the lift-off technique, and the second lead and the second electrode area are defined by photoresist on this insulating layer thin film. Leads and electrodes are plated by methods such as evaporation plating, magnetron sputtering, electron beam evaporation, etc., and then the photoresist is removed by the lift-off technique to lay the second lead 6 and the second electrode 8; then metal filling in the through holes 4 is formed by methods such as seed layer sputtering and through hole electroplating to form metal filling columns 9, and the involved metal filling materials include one or more of copper, gold, chromium, and titanium; finally, the glass substrate 7 is thinned through a surface planarization technique so that the metal filling columns 9 protrude from the upper surface of the second substrate 7.

[0037] The above are only the preferred embodiments of the present invention, and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that: within the spirit and principle of the present invention, any modification to the technical solutions described in the foregoing embodiments, or any equivalent replacement of some or all of the technical features, and these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention, and should all be included within the protection scope of the present invention.

Claims

1. A high-density infrared photoelectric focal plane array sensor, characterized in that: The invention comprises a superimposed and connected sensitive element chip and a through-hole component, wherein the sensitive element chip comprises a first substrate (1), a plurality of sensitive elements (2) arranged on the first substrate (1), and a plurality of pairs of electrodes (3) arranged at both ends of each sensitive element (2); the through-hole component comprises a second substrate (7), a plurality of pairs of through holes (4) arranged on the second substrate (7), and metal filling columns (9) arranged in the through holes (4), each pair of electrodes (3) corresponds to a pair of through holes (4) in a one-to-one manner, and the ends of the metal filling columns (9) are welded and connected to the electrodes (3).

2. The high-density infrared photoelectric focal plane array sensor according to claim 1, characterized in that: The metal filling column (9) is connected to the electrode (3) via a welding point (10).

3. The high-density infrared photoelectric focal plane array sensor according to claim 1 or 2, characterized in that: The second substrate (7) is a glass substrate.

4. The high-density infrared photoelectric focal plane array sensor according to claim 3, characterized in that: The second substrate (7) is provided with a lead wire connected to each through hole (4) and a second electrode (8) connected to the lead wire.

5. The high-density infrared photoelectric focal plane array sensor according to claim 4, characterized in that: The leads include a plurality of first leads (5) arranged at intervals and a plurality of second leads (6) arranged at intervals, and one through hole (4) of each pair of through holes (4) is connected to the first lead (5) and the other through hole (4) is connected to the second lead (6).

6. The high-density infrared photoelectric focal plane array sensor according to claim 5, characterized in that: The through holes (4) are arranged in a rectangular array, and the first leads (5) and the second leads (6) are arranged vertically and horizontally; each pair of through holes (4) comprises a left through hole and a right through hole, each column of left through holes is connected to a first lead (5), and each right through hole in each column of right through holes is connected to a second lead (6).

7. The high-density infrared photoelectric focal plane array sensor according to claim 6, characterized in that: Each first lead (5) comprises a first main lead arranged longitudinally and a plurality of first branch leads connected to the first main lead, the first branch leads are arranged transversely, and the plurality of first branch leads are respectively connected to the left through holes of a corresponding column; the end of each first main lead is connected to a second electrode (8).

8. The high-density infrared photoelectric focal plane array sensor according to claim 6 or 7, characterized in that: Each second lead (6) comprises a second main lead arranged transversely and a plurality of second branch leads connected to the second main lead, the second branch leads are arranged longitudinally, and the plurality of second branch leads are respectively connected to a corresponding row of right through holes; the end of each second main lead is connected to a second electrode (8).

9. The high-density infrared photoelectric focal plane array sensor according to claim 2, characterized in that: The side projection of the solder joint (10) is a semicircular structure, and the straight side of the semicircular structure faces the sensitive element chip and is connected to the end of the metal filling column (9).

10. The high-density infrared photoelectric focal plane array sensor according to claim 9, characterized in that: One end of the metal filling column (9) away from the electrode (3) protrudes from the surface of the second substrate (7).

Images