Dual-band visible and short-wave infrared detector

Abstract

The visible light and short-wave infrared dual-band detector comprises a tube shell, a cover plate, a thermoelectric refrigerator, a short-wave infrared chip set, a multilayer ceramic substrate with a cavity, a microlens array, a silicon-based visible light chip, an anti-reflection film and a coffering glue, the cover plate with a window is welded on the upper end of the tube shell, the multilayer ceramic substrate with a cavity is fixed on the bottom plate of the tube shell, the thermoelectric refrigerator is arranged on the bottom surface of the ceramic cavity, the short-wave infrared chip set is arranged on the thermoelectric refrigerator in the ceramic cavity, the microlens array is arranged on the light-sensitive surface of the silicon-based visible light chip, the anti-reflection film is made on the back light surface of the silicon-based visible light chip, the coffering glue is coated on the outer periphery of the short-wave infrared readout circuit chip, the silicon-based visible light chip with the anti-reflection film is fixed on the coffering glue, so that the pixels of the silicon-based visible light chip are aligned with the pixels of the indium gallium arsenide short-wave infrared light-sensitive chip in an up-down manner and one-to-one correspondence, the filling glue is filled between the anti-reflection film and the light-sensitive surface of the indium gallium arsenide short-wave infrared light-sensitive chip, and the silicon-based visible light chip and the indium gallium arsenide short-wave infrared chip are connected with the ceramic substrate through lead bonding wires.

Description

Technical Field

[0001] This invention relates to the field of photodetectors, and in particular to a dual-band detector for visible light and short-wave infrared. Background Technology

[0002] Multi-spectral, high-resolution photoelectric detection is the trend in detector development, playing a disruptive role in miniaturization, low power consumption, high precision, and high anti-interference capabilities of photoelectric instruments and equipment. Nighttime light sources such as moonlight, atmospheric glow, and starlight, present in dark environments, primarily have energy concentrated in the visible-shortwave infrared band (0.4–1.7 μm). To achieve high-quality imaging in low-light night vision environments, visible-shortwave infrared dual-band detectors have become a research hotspot. These detectors combine the advantages of visible light detectors and infrared detectors, having a disruptive impact on many visible-infrared fusion application fields. They can be used in automotive lidar, deep space exploration, Earth mineral resource exploration, soil monitoring, vegetation water content and atmospheric composition changes, crop yield estimation, and disaster prevention and mitigation, among other fields.

[0003] To achieve visible-shortwave infrared detection, existing technologies include the following solutions:

[0004] 1. Extend the response band of photosensitive chips. For example, by removing the InP substrate, the response band of an InGaAs infrared detector can be extended from 0.9μm to about 0.5μm, covering the visible light band. In this technology, visible light and short-wave infrared need to correspond to different pixels for response. For example, one short-wave infrared pixel is set in every four sub-pixels, which actually sacrifices the resolution of the entire array.

[0005] 2. Different wavelength bands can be detected through device integration technology. For example, patent CN 108346713 B discloses a visible-shortwave infrared detector, which forms a visible light detector on the back of the silicon substrate and a shortwave infrared detector on the front of the silicon substrate. The problem with this technology is that the process is complex and the process flow is long. The failure of each device will lead to the scrapping of the whole device. In addition, the two detectors share a readout circuit, making the circuit design difficult.

[0006] Chip-level stacked packaging is widely used in the integrated circuit industry to achieve high-density integration. Upper and lower chips are interconnected via flip-chip bonding or wire bonding, or individually led out via wire bonding. However, in the optoelectronic field, because photosensitive chips need to receive incident light from a window, and because the upper chip's obstruction reduces the external quantum efficiency of the lower chip, stacked packaging becomes more difficult. Therefore, visible-shortwave infrared stacked packaging is rarely reported.

[0007] In conventional integrated device technology, the silicon process for visible light detectors is incompatible with the compound semiconductor process for short-wave infrared detectors, making it difficult to integrate and fabricate visible-short-wave infrared detectors. Patent CN 108346713 B reports a visible-short-wave infrared detector compatible with silicon semiconductor processes, which fabricates visible light detectors and short-wave infrared detectors on opposite sides of the readout circuit. However, its readout circuit design is difficult, the device process flow is complex, and the yield is low.

[0008] It is evident that current technologies for visible-shortwave infrared detection either struggle to achieve high resolution or suffer from difficulties in device design, complex device fabrication processes, and long workflows, which can easily lead to low yield rates. Summary of the Invention

[0009] The purpose of this invention is to provide a miniaturized dual-band detector for visible light and short-wave infrared, which achieves high-resolution imaging of both visible light and short-wave infrared without increasing the overall design and manufacturing complexity.

[0010] To achieve the purpose of this invention, the following technical solution is adopted:

[0011] This invention discloses a dual-band detector for visible light and short-wave infrared, comprising: a housing, a cover plate, a thermoelectric cooler, a short-wave infrared chip assembly, and a multilayer ceramic substrate with a cavity. The cover plate is welded to the upper end of the housing and has a window that allows light to enter the space enclosed by the cover plate and the housing. A multilayer ceramic substrate with a cavity is disposed at the lower end of the housing. A thermoelectric cooler is disposed within the cavity of the multilayer ceramic substrate. The short-wave infrared chip assembly is disposed on the thermoelectric cooler and includes: a short-wave infrared readout circuit chip and an indium gallium arsenide (IGaAs) short-wave infrared photosensitive chip. The short-wave infrared readout circuit chip is disposed on the thermoelectric cooler, and the IGaAs short-wave infrared photosensitive chip is interconnected to the top of the short-wave infrared readout circuit chip via indium pillars. The short-wave infrared readout circuit chip is connected to the housing via wire bonding wires. A multilayer ceramic substrate with a cavity is connected, and several lead-out pins are soldered to the bottom surface of the multilayer ceramic substrate. They extend through the lower end of the tube shell bottom plate. The visible light and short-wave infrared dual-band detector also includes a microlens array, a silicon-based visible light chip, an anti-reflection film, and a damming adhesive. The microlens array is set on the photosensitive surface of the silicon-based visible light chip, the anti-reflection film is fabricated on the back surface of the silicon-based visible light chip, and the damming adhesive is applied to the outer periphery of the short-wave infrared readout circuit chip. The silicon-based visible light chip with the anti-reflection film is fixed on the damming adhesive, so that the pixels of the silicon-based visible light chip are vertically aligned and correspond one-to-one with the pixels of the indium gallium arsenide short-wave infrared photosensitive chip. Filler adhesive is filled between the anti-reflection film and the photosensitive surface of the indium gallium arsenide short-wave infrared photosensitive chip. The silicon-based visible light chip is connected to the multilayer ceramic substrate with a cavity through wire bonding wires.

[0012] The present invention relates to a dual-band detector for visible light and short-wave infrared, wherein: the confining adhesive contains spherical spacers with a particle size of 15-200 μm, and the distance between the photosensitive surface of the indium gallium arsenide short-wave infrared photosensitive chip and the backlight surface of the silicon-based visible light chip is adjusted by the particle size of the aforementioned spherical spacers.

[0013] The present invention provides a dual-band detector for visible light and short-wave infrared, wherein: a step is provided inside the cavity of the multilayer ceramic substrate with cavity, and the short-wave infrared readout circuit chip is connected to the bonding point on the step through a lead bonding wire.

[0014] The present invention provides a dual-band detector for visible light and short-wave infrared, wherein the silicon-based visible light chip is connected to a bonding point on the upper end of a multilayer ceramic substrate via wire bonding wires.

[0015] The present invention relates to a dual-band detector for visible light and short-wave infrared, wherein the aperture ratio of the silicon-based visible light chip is above 50%.

[0016] The present invention provides a dual-band detector for visible light and short-wave infrared, wherein the silicon substrate of the silicon-based visible light chip is 200-300 μm.

[0017] The present invention provides a dual-band detector for visible light and short-wave infrared, wherein the silicon-based visible light chip has a response band of 350nm to 1050nm.

[0018] The present invention provides a dual-band detector for visible light and short-wave infrared, wherein the microlens array is made of silicon nitride or sapphire material.

[0019] The visible light and short-wave infrared dual-band detector of the present invention can realize miniaturized visible-short-wave infrared simultaneous staring imaging without sacrificing device resolution, and the present invention does not increase the overall chip design and process complexity. Attached Figure Description

[0020] Figure 1 This is a front cross-sectional schematic diagram of the visible light and short-wave infrared dual-band detector of the present invention;

[0021] Figure 2 This is a three-dimensional partial cross-sectional schematic diagram of the visible light and short-wave infrared dual-band detector of the present invention.

[0022] exist Figure 1 and Figure 2In the diagram, 1 is the window; 2 is the cover plate; 3 is the microlens array; 4 is the silicon-based visible light chip; 5 is the antireflective coating; 6 is the cofferdam adhesive; 7 is the step; 8 is the lead-out pin; 9 is the thermoelectric cooler; 10 is the tube shell; 11 is the indium pillar; 12 is the short-wave infrared readout circuit chip; 13 is the indium gallium arsenide short-wave infrared photosensitive chip; 14 is the ceramic substrate; 15 is the filler adhesive; and 16 is the wire bonding wire. Detailed Implementation

[0023] like Figure 1 and Figure 2 As shown, the present invention provides a dual-band detector for visible light and short-wave infrared, comprising: a cover plate 2, a thermoelectric cooler 9, a tube shell 10, a short-wave infrared chip group, a multilayer ceramic substrate 14 with a cavity, a microlens array 3, a silicon-based visible light chip 4, an antireflective film 5, and a containment adhesive 6. A cover plate 2 is welded to the upper end of the tube shell 7. A window 1 is opened on the cover plate 2, allowing light to enter the space enclosed by the cover plate 2 and the tube shell 7 through the window 1. A multilayer ceramic substrate 14 with a cavity is provided at the lower end of the tube shell 10. A thermoelectric cooler 9 is provided on the bottom surface of the cavity of the ceramic substrate. A short-wave infrared chip group is provided on the thermoelectric cooler 9. The short-wave infrared chip group includes a short-wave infrared readout circuit chip 12 and an indium gallium arsenide short-wave infrared photosensitive chip 13. The short-wave infrared readout circuit chip 12 is provided on the thermoelectric cooler 9. The indium gallium arsenide short-wave infrared photosensitive chip 13 is interconnected on the top of the short-wave infrared readout circuit chip 12 through indium pillars 11. There is a step 7 on the inner side of the cavity of the multilayer ceramic substrate 14. The short-wave infrared readout circuit chip 12 is connected to the bonding point on the step 7 through a lead bonding wire 16. The cutoff wavelength of the indium gallium arsenide short-wave infrared photosensitive chip 13 is 1.7μm. Several lead pins 8 are soldered to the bottom surface of the multilayer ceramic substrate 14, and they extend through the lower end of the bottom plate of the casing 10.

[0024] A microlens array 3 is disposed on the photosensitive surface of the silicon-based visible light chip 4, an antireflection film 5 is fabricated on the backlight surface of the silicon-based visible light chip 4, and a damming adhesive 6 is applied to the outer periphery of the short-wave infrared readout circuit chip 12. The silicon-based visible light chip 4 with the antireflection film 5 is fixed on the damming adhesive 6, so that the pixels of the silicon-based visible light chip 4 and the pixels of the indium gallium arsenide short-wave infrared photosensitive chip 13 are aligned vertically and correspond one-to-one by alignment marks. The damming adhesive 6 contains spherical spacers with a particle size of 15-200 μm, for example, the spherical spacers are silicon oxide spheres with a diameter of 50 μm or 20 μm. The distance between the photosensitive surface of the indium gallium arsenide short-wave infrared photosensitive chip 13 and the backlight surface of the silicon-based visible light chip 4 is adjusted by the particle size of the aforementioned spherical spacers. A filler adhesive 15 is filled between the antireflection film 5 and the photosensitive surface of the indium gallium arsenide short-wave infrared photosensitive chip 13. The silicon-based visible light chip 4 is connected to the bonding point at the upper end of the ceramic cavity 14 through a lead bonding wire 16.

[0025] The silicon-based visible light chip 4 has an aperture ratio of over 50%, for example, 70% or 85%. The silicon-based visible light chip 4 is a common type of visible light chip, with a response wavelength of 350nm to 1050nm. The microlens array 3 is made of silicon nitride or sapphire material. The microlens array focuses the incident light to the center of the pixel, improving the quantum efficiency of the photosensitive sensor and ensuring broad spectral transmission in the visible-short-wave infrared range.

[0026] Both the photosensitive side of the indium gallium arsenide short-wave infrared photosensitive chip 13 and the backlight side of the silicon-based visible light chip 4 have alignment marks, so that the pixels of the silicon-based visible light chip 4 and the pixels of the indium gallium arsenide short-wave infrared photosensitive chip 13 are aligned vertically by the above-mentioned alignment marks and correspond one-to-one.

[0027] The key features of the visible light and short-wave infrared dual-band detector of this invention are:

[0028] (1) The two chips, indium gallium arsenide short-wave infrared photosensitive chip 13 and silicon-based visible light chip 4, are vertically stacked by spherical spacers. The stacking does not affect the imaging function of the lower indium gallium arsenide short-wave infrared photosensitive chip 13.

[0029] (2) By using a vertically stacked packaging structure, the indium gallium arsenide short-wave infrared photosensitive chip 13 and the silicon-based visible light chip 4 can be simultaneously stared at for imaging without sacrificing the chip resolution.

[0030] (3) In a single package, the indium gallium arsenide short-wave infrared photosensitive chip 13 and the silicon-based visible light chip 4 can be imaged simultaneously without the need to set up separate filter structures, thus reducing system complexity.

[0031] The above is merely one embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any modifications that can be easily conceived by those skilled in the art within the scope of the technology disclosed in the present invention should be included within the scope of protection of the present invention.

Claims

1. A dual-band detector for visible light and short-wave infrared, comprising: The system comprises a casing (10), a cover plate (2), a thermoelectric cooler (9), a short-wave infrared chip assembly, and a multilayer ceramic substrate (14) with a cavity. The cover plate (2) is welded to the upper end of the casing (10). A window (1) is opened on the cover plate (2) so that light can enter the space enclosed by the cover plate (2) and the casing (10) through the window (1). A multilayer ceramic substrate (14) with a cavity is provided at the lower end of the casing (10). The thermoelectric cooler (9) is provided in the cavity of the multilayer ceramic substrate (14). A short-wave infrared chip assembly is mounted on a thermoelectric cooler (9). The short-wave infrared chip assembly includes a short-wave infrared readout circuit chip (12) and an indium gallium arsenide (IGaAs) short-wave infrared photosensitive chip (13). The short-wave infrared readout circuit chip (12) is mounted on the thermoelectric cooler (9). The IGaAs short-wave infrared photosensitive chip (13) is interconnected to the top of the short-wave infrared readout circuit chip (12) via an indium pillar (11). The short-wave infrared readout circuit chip (12) is connected to a multilayer ceramic substrate with a cavity via a wire bonding wire (16). 14) Connected, several lead-out pins (8) are welded to the bottom surface of the multilayer ceramic substrate (14) with cavity, and extend through the lower end of the tube shell (10). The feature is that the visible light and short-wave infrared dual-band detector further includes: microlens array (3), silicon-based visible light chip (4), anti-reflection film (5) and damming adhesive (6). The microlens array (3) is set on the photosensitive surface of the silicon-based visible light chip (4), the anti-reflection film (5) is made on the backlight surface of the silicon-based visible light chip (4), and the damming adhesive (6) is applied to the short-wave infrared chip. On the outer periphery of the infrared readout circuit chip (12), a silicon-based visible light chip (4) with an anti-reflection film (5) is fixed on a dam adhesive (6), so that the pixels of the silicon-based visible light chip (4) are aligned vertically and correspond one-to-one with the pixels of the indium gallium arsenide short-wave infrared photosensitive chip (13). A filler adhesive (15) is filled between the anti-reflection film (5) and the photosensitive surface of the indium gallium arsenide short-wave infrared photosensitive chip (13). The silicon-based visible light chip (4) is connected to a multilayer ceramic substrate (14) with a cavity through a wire bonding wire (16).

2. The visible light and short-wave infrared dual-band detector as described in claim 1, characterized in that: The containment adhesive (6) contains spherical spacers with a particle size of 15-200 μm. The distance between the photosensitive surface of the indium gallium arsenide short-wave infrared photosensitive chip (13) and the backlight surface of the silicon-based visible light chip (4) is adjusted by the particle size of the spherical spacers.

3. The visible light and short-wave infrared dual-band detector as described in claim 2, characterized in that: A step (7) is provided on the inner side of the multilayer ceramic substrate (14) with cavity, and the short-wave infrared readout circuit chip (12) is connected to the bonding point on the step (7) through the lead bonding wire (16).

4. The visible light and short-wave infrared dual-band detector as described in claim 3, characterized in that: The silicon-based visible light chip (4) is connected to the bonding point at the upper end of the multilayer ceramic substrate (14) with cavity via a lead bonding wire (16).

5. The visible light and short-wave infrared dual-band detector as described in claim 4, characterized in that: The aperture ratio of the silicon-based visible light chip (4) is above 50%.

6. The visible light and short-wave infrared dual-band detector as described in claim 5, characterized in that: The silicon substrate of the silicon-based visible light chip (4) is 200-300μm.

7. The visible light and short-wave infrared dual-band detector as described in claim 6, characterized in that: The silicon-based visible light chip (4) has a response wavelength of 350nm to 1050nm.

8. The visible light and short-wave infrared dual-band detector as described in claim 7, characterized in that: The microlens array (3) is made of silicon nitride or sapphire material.

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