Infrared detector and chip structure and processing technology thereof

Abstract

The present invention relates to the field of infrared detection technology, and in particular to an infrared detector and its chip structure and processing technology, wherein the chip structure includes a shell, a window, a separation ring, two getters, an even number of pressure sensors and a chip body, the window and the shell are bonded to form a vacuum cavity, the separation ring is made of elastic material, and is inserted in the vacuum cavity, and divides the vacuum cavity into two chambers that are not connected to each other, the two getters are respectively inserted in the two chambers, and are used to absorb the gas in the respective chambers, the pressure sensors are grouped in pairs, and the two pressure sensors in the same group are respectively inserted in the two chambers and are located on both sides of the separation ring, and the pressure sensors are configured to sense the corresponding pressure when the separation ring expands or contracts, and send a signal to start the corresponding getter, so as to avoid the influence of external gas on the vacuum degree of the chamber where the chip body is located when it penetrates from the side wall of the shell, and at the same time, the corresponding getter can be started in time.

Description

Technical Field

[0001] The present invention relates to the field of infrared detection technology, and in particular to an infrared detector and a chip structure and a processing technology thereof. Background Art

[0002] A thermal imaging system is a device that uses infrared technology to detect and display the temperature distribution on the surface of an object. It mainly collects light in the thermal infrared band and converts the thermal radiation emitted by the object into grayscale values ​​or pseudo-color images to discover and identify the target object. The core component of the thermal imaging system is the infrared detector, which can detect infrared radiation and convert it into electrical signals.

[0003] In the related art, in order to ensure the sensitivity and accuracy of the infrared detector in temperature measurement, the infrared detector chip has strict requirements on the environment inside the detector. The temperature change of the infrared detector microbolometer after receiving the target infrared radiation is very weak. In order to maintain the heat on it and avoid heat exchange with air molecules, it needs to be placed in a vacuum environment for operation. For example, a Chinese reference document with authorization announcement number CN102956662B discloses a vacuum-sealed packaging structure and packaging method for an infrared focal plane detector chip. The vacuum-sealed packaging structure of the infrared focal plane detector chip installs a getter in the cavity to absorb the gas released from the inner wall of the cavity and the internal components to maintain the vacuum degree of the packaging structure.

[0004] Existing infrared detectors often have poor response rates, blurred imaging, or even no imaging when in use due to insufficient vacuum. There are two main ways to judge whether the vacuum has dropped to the point where the getter needs to be activated. One way is to remove the infrared detector micro-dewar assembly from the imaging system and indirectly judge whether the vacuum has dropped by measuring parameters such as the thermal load and refrigeration start-up time of the infrared detector. Although it can judge the vacuum condition inside the infrared detector, it requires the use of special measuring instruments during detection, and the technology is highly professional, the cycle is long, and the workload is large. Another way is to periodically activate the getter based on statistical data obtained from preliminary tests or human experience during use. This method of periodically activating the getter is performed without knowing the actual vacuum inside the assembly, and since the leakage conditions of each micro-dewar and the degree of degassing on the surface of parts in the vacuum chamber are different, it is difficult to determine the activation cycle in actual operation. Summary of the invention

[0005] Based on this, it is necessary to provide an infrared detector and its chip structure and processing technology to address the problem that the current infrared detector cannot activate the getter in time to maintain the vacuum degree during use.

[0006] The above purpose is achieved through the following technical solutions:

[0007] A chip structure, comprising:

[0008] shell;

[0009] A window sheet, wherein the window sheet and the housing are bonded to form a vacuum cavity;

[0010] A separator ring, which is made of an elastic material and is inserted into the vacuum chamber to separate the vacuum chamber into an outer chamber and an inner chamber that are not connected to each other;

[0011] two getters, respectively inserted in the outer chamber and the inner chamber, and configured to absorb gas in the outer chamber or the inner chamber;

[0012] An even number of pressure sensors, in groups of two, wherein the two pressure sensors in the same group are respectively inserted into the outer chamber and the inner chamber and are located on both sides of the separation ring, wherein the pressure sensors are configured to sense corresponding pressure when the separation ring expands or contracts, and send signals to start the corresponding getter;

[0013] A chip body is inserted into the inner cavity.

[0014] Furthermore, the chip structure also includes a refrigeration unit, which is inserted between the chip body and the housing and is configured to be able to cool so that the chip body works at a constant temperature.

[0015] Furthermore, the cooling unit includes a thermoelectric cooler.

[0016] Furthermore, there are four pressure sensors, and two groups of pressure sensors are symmetrically arranged about the separation ring.

[0017] Furthermore, the pressure sensor is a MEMS pressure sensor.

[0018] Furthermore, an optical window is arranged on the window piece.

[0019] Furthermore, the getter is an electrically activated getter.

[0020] Furthermore, the shell is made of ceramic.

[0021] The invention also provides an infrared detector, comprising a chip structure.

[0022] The present invention also provides a processing technology for an infrared detector, including an infrared detector, wherein the processing technology for the infrared detector includes the following steps:

[0023] The separation ring, the getter and the pressure sensor are all welded in the cavity of the housing;

[0024] Installing the chip body inside the separation ring;

[0025] The window piece is sealed and connected to the housing and the separation ring at the same time.

[0026] The beneficial effects of the present invention are:

[0027] The invention relates to an infrared detector and a chip structure and a processing technology thereof. The infrared detector comprises a chip structure. The processing technology of the infrared detector comprises a processing step of the infrared detector. When the infrared detector is in use, when the pressure inside an outer chamber is greater than the pressure inside an inner chamber, a separation ring is compressed and contracted and sensed by an inner pressure sensor. The pressure sensor sends a signal to start an outer getter to absorb the gas inside the outer chamber, thereby ensuring the vacuum degree of the outer chamber and avoiding affecting the vacuum degree of the inner chamber. When the pressure inside the outer chamber is less than the pressure inside the inner chamber, the separation ring is compressed and expanded and sensed by an outer pressure sensor. The pressure sensor sends a signal to start an inner getter to absorb the gas inside the inner chamber, thereby ensuring the vacuum degree of the inner chamber and avoiding affecting the imaging accuracy of the infrared detector. By arranging the separation ring and the pressure sensor, on the one hand, a chip body and a side wall of an outer shell are separated, which helps to reduce the influence of external gas infiltrating from the side wall of the outer shell and the gas released by the side wall of the outer shell on the vacuum degree of the chamber where the chip body is located, and on the other hand, helps to start the getter on the corresponding side in time, while ensuring the vacuum degree of the inner chamber, ensuring the imaging accuracy. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 A schematic diagram of a three-dimensional structure of a chip structure provided by an embodiment of the present invention;

[0029] Figure 2 A schematic diagram of an exploded structure of parts of a chip structure provided by an embodiment of the present invention;

[0030] Figure 3 A schematic diagram of a top view of a chip structure without a window sheet provided by an embodiment of the present invention;

[0031] Figure 4 for Figure 3 Middle AA section view;

[0032] Figure 5 for Figure 4 Schematic diagram of the local enlarged structure at point B in the middle.

[0033] in:

[0034] 1. Shell; 101. Mounting frame; 11. Welding plate; 12. Pins; 13. Pressure sensor; 14. Getter;

[0035] 2. Separation ring;

[0036] 3. Chip body;

[0037] 4. Window piece. DETAILED DESCRIPTION

[0038] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below through embodiments and in conjunction with the accompanying drawings. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0039] The serial numbers assigned to the components herein, such as "first", "second", etc., are only used to distinguish the objects described and do not have any order or technical meaning. The "connection" and "coupling" mentioned in this application, unless otherwise specified, include direct and indirect connections (couplings). In the description of the present invention, it should be understood that the orientation or position relationship indicated by the terms "upper", "lower", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", etc. are based on the orientation or position relationship shown in the accompanying drawings, which is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation to the present invention.

[0040] In the present invention, unless otherwise clearly specified and limited, a first feature being "above" or "below" a second feature may mean that the first and second features are in direct contact, or the first and second features are in indirect contact through an intermediate medium. Moreover, a first feature being "above", "above" or "above" a second feature may mean that the first feature is directly above or obliquely above the second feature, or simply means that the first feature is higher in level than the second feature. A first feature being "below", "below" or "below" a second feature may mean that the first feature is directly below or obliquely below the second feature, or simply means that the first feature is lower in level than the second feature.

[0041] like Figures 1 to 5 As shown, a chip structure provided by an embodiment of the present invention; in this embodiment, the chip structure is configured to include a housing 1, a window 4, a separation ring 2, two getters 14, an even number of pressure sensors 13 and a chip body 3, wherein the housing 1 is configured as a box structure with an open upper surface, and can be configured to be made of ceramics. The housing 1 made of ceramic material has excellent mechanical properties, thermal stability, insulation performance, airtightness, moisture resistance, light-shielding performance, etc., and can effectively reduce the volume and weight of the packaged detector, and reduce the raw material cost and manufacturing cost; the window 4 and the housing 1 are bonded to form a vacuum cavity, specifically, as Figure 2As shown, the window piece 4 is configured to be a sheet structure with a square shape, and a square mounting frame 101 is fixedly arranged inside the shell 1, the outer wall of the mounting frame 101 and the inner wall of the shell 1 are arranged to overlap, and the upper surface of the mounting frame 101 is located between the upper surface and the upper bottom surface of the shell 1, forming a step pattern, and the window piece 4 is configured to cover the top of the mounting frame 101 when installed, and the lower surface of the window piece 4, the inner wall of the mounting frame 101 and the upper bottom surface of the shell 1 together surround to form a vacuum cavity; more specifically, the window piece 4 is configured to be made of wafer material to ensure the transmittance of infrared radiation in the required band.

[0042] The separation ring 2 is made of elastic material and is inserted into the vacuum chamber to separate the vacuum chamber into an outer chamber and an inner chamber that are not connected to each other. Specifically, Figure 2 and Figure 3 As shown, the separator ring 2 is configured as a square frame structure, and is inserted between the window piece 4 and the outer shell 1 during installation, the side walls of the separator ring 2 and the side walls of the outer shell 1 are arranged in parallel one by one, and the lower surface of the window piece 4, the inner side wall of the separator ring 2 and the upper bottom surface of the outer shell 1 together surround an inner chamber, and the lower surface of the window piece 4, the inner side wall of the mounting frame 101, the outer side wall of the separator ring 2 and the upper bottom surface of the outer shell 1 together surround an outer chamber; more specifically, the elastic material includes but is not limited to rubber, and when the separator ring 2 is made of rubber, a square metal frame structure can be arranged at both ends of the separator ring 2, so that the separator ring 2 can be welded to the window piece 4 and the outer shell 1 respectively; more specifically, the extension trajectory of the separator ring 2 in the vertical direction can be set to an S shape, so that it is easier to deform when the pressures in the outer chamber and the inner chamber are not equal, thereby improving the control accuracy of the start-up of the getter 14.

[0043] Two getters 14 are respectively inserted into the outer chamber and the inner chamber, and are configured to absorb the gas inside the outer chamber or the inner chamber. Specifically, Figure 3 As shown, the getter 14 on the left is arranged on the upper bottom surface of the housing 1 and is located between the mounting frame 101 and the separation ring 2 , and the getter 14 on the right is arranged on the upper bottom surface of the housing 1 and is located inside the separation ring 2 .

[0044] In this embodiment, the getter 14 can be set as an electrically activated getter 14. Specifically, a metal activation electrode for electrically activating the getter 14 is provided on the outer shell 1. During activation, only the getter 14 is heated to avoid an increase in the overall temperature of the detector, thereby avoiding problems such as structural thermal failure, detector packaging failure, and solder overflow caused by thermal activation, and multiple activations can be achieved to ensure the vacuum degree in the vacuum chamber.

[0045] The pressure sensors 13 are arranged in pairs, and the two pressure sensors 13 in the same group are respectively inserted into the outer chamber and the inner chamber, and are located on both sides of the separation ring 2. Specifically, taking the number of pressure sensors 13 as an example, the pressure sensors 13 are divided into two groups in total, and the two groups are symmetrically arranged about the separation ring 2, such as Figure 3 As shown, one pressure sensor 13 of one group is arranged on the upper bottom surface of the shell 1 and is located between the upper side wall of the mounting frame 101 and the upper side wall of the separation ring 2, another pressure sensor 13 is arranged on the upper bottom surface of the shell 1 and is located below the upper side wall of the separation ring 2, one pressure sensor 13 of the other group is arranged on the upper bottom surface of the shell 1 and is located between the lower side wall of the mounting frame 101 and the lower side wall of the separation ring 2, and another pressure sensor 13 is arranged on the upper bottom surface of the shell 1 and is located above the lower side wall of the separation ring 2; the pressure sensors 13 are configured to sense the corresponding pressure when the separation ring 2 expands or contracts, and send a signal to start the corresponding getter 14.

[0046] In this embodiment, the pressure sensor 13 can be set as a MEMS pressure sensor. Specifically, the MEMS pressure sensor mainly refers to a silicon-based pressure sensor. The silicon-based pressure sensor refers to a sensor prepared by utilizing the piezoresistive effect of single-crystal silicon material and drawing on the processing technology related to integrated circuits. Its characteristic parameters are generally in the um order of magnitude, and it has the advantages of small size, low power consumption, and high reliability. By adopting a MEMS pressure sensor, the volume of the housing 1 can be further reduced; and compared with the use of a vacuum sensor, such as a Pirani vacuum gauge sensor, the Pirani vacuum gauge sensor includes a heating component, such as a heating wire or a film, which is usually heated to a high temperature by using a bridge circuit. When the density of gas molecules changes, the heat transfer from the metal wire to the gas will be affected. This heat loss depends on the gas type and pressure, and the energy required to keep the metal wire at temperature also changes accordingly, thereby reflecting the vacuum degree. However, this vacuum sensor will generate heat when in use, which will affect the detection accuracy of the detector, resulting in a large imaging error.

[0047] The chip body 3 is inserted into the inner cavity. Specifically, Figure 2 As shown, a welding plate 11 is arranged on the upper bottom surface of the shell 1, and the chip body 3 is welded on the upper surface of the welding plate 11 and electrically connected to the welding plate 11 during installation, and a pin 12 is arranged at the bottom of the welding plate 11, and the pin 12 passes through and extends out of the bottom wall surface of the shell 1, and is used to be electrically connected to the detector; more specifically, the pressure sensor 13 located on the inner side of the separation ring 2 is arranged to be welded on the welding plate 11 and electrically connected to the welding plate 11 during installation.

[0048] During use, when the pressure inside the outer chamber is greater than the pressure inside the inner chamber, the separation ring 2 is compressed and contracted and sensed by the pressure sensor 13 on the inside. The pressure sensor 13 sends a signal to start the outer getter 14 to absorb the gas inside the outer chamber, thereby ensuring the vacuum degree of the outer chamber and avoiding affecting the vacuum degree of the inner chamber; when the pressure inside the outer chamber is less than the pressure inside the inner chamber, the separation ring 2 is compressed and expanded and sensed by the pressure sensor 13 on the outside. The pressure sensor 13 sends a signal to start the inner getter 14 to absorb the gas inside the inner chamber, thereby ensuring the vacuum degree of the inner chamber and avoiding affecting the imaging accuracy of the infrared detector; by setting the separation ring 2 and the pressure sensor 13, on the one hand, the chip body 3 and the side wall of the shell 1 are separated, which helps to reduce the influence of the external gas infiltrating from the side wall of the shell 1 and the gas released from the side wall of the shell 1 on the vacuum degree of the chamber where the chip body 3 is located, and on the other hand, it helps to start the getter 14 on the corresponding side in time, while ensuring the vacuum degree of the inner chamber, ensuring the imaging accuracy.

[0049] It can be understood that the gas outside the outer shell 1 can enter the outer chamber through the weld gap between the outer shell 1 and the window plate, thereby causing the pressure inside the outer chamber to gradually increase; the gas inside the outer chamber can enter the inner chamber through the weld gap between the separating ring 2 and the outer shell 1 and the window plate, thereby causing the pressure inside the inner chamber to gradually increase; the gas naturally released from the outer shell 1 and its internal components will cause the pressure inside the outer chamber and the inner chamber to gradually increase.

[0050] It is understandable that in extreme cases, when the pressure inside the outer chamber is equal to the pressure inside the inner chamber and both gradually rise, the detector imaging will still be unclear. At this time, the two getters 14 can be manually started to respectively extract the gas from the outer chamber and the inner chamber, thereby maintaining the vacuum degree inside the outer chamber and the inner chamber.

[0051] In a further embodiment, the chip structure is configured to also include a refrigeration unit, which is inserted between the chip body 3 and the housing 1 and is configured to be able to provide cooling so that the chip body 3 operates at a constant temperature, thereby reducing the impact of the heat generated by the chip structure itself on imaging accuracy.

[0052] In this embodiment, the refrigeration part is configured to include a thermoelectric refrigerator. Specifically, the thermoelectric refrigerator is a device that uses the thermoelectric effect to convert electrical energy into cooling capacity. It is mainly achieved through the Peltier effect. This effect is that when current passes through a thermocouple composed of two different materials, a temperature difference will be generated at both ends of the thermocouple, thereby realizing the transfer of heat from one end to the other end; the working principle of the thermoelectric refrigerator is based on the characteristics of thermoelectric materials. These materials are usually composed of two different metals or semiconductor materials, which will produce a thermoelectric effect between them. When power is turned on, the generated current will cause a temperature difference, thereby forming a cooling effect, so that the chip body 3 can work at a constant temperature.

[0053] In other embodiments, the number of the pressure sensors 13 may also be two, such as Figure 3 As shown, the two pressure sensors 13 can be arranged on the upper and lower sides of the upper side wall of the separation ring 2, or on the upper and lower sides of the lower side wall of the separation ring 2, so as to sense the expansion or contraction of the separation ring 2 in real time.

[0054] In other embodiments, an optical window is provided on the window plate 4, so as to enhance the transmittance of infrared radiation in a required band, reduce stray light, and further improve the performance of the detector.

[0055] In other embodiments, the material of the housing 1 includes but is not limited to aluminum oxide and aluminum nitride.

[0056] An embodiment of the present invention further provides an infrared detector, comprising any one of the above chip structures.

[0057] Another embodiment of the present invention further provides a processing technology for an infrared detector, which is applied to the above-mentioned infrared detector. The processing technology for the infrared detector includes the following steps:

[0058] The separation ring 2, the getter 14 and the pressure sensor 13 are all welded in the cavity of the housing 1;

[0059] Specifically, the getter 14 can be welded to the upper bottom surface of the housing 1 by a cold welding machine using a butt welding process.

[0060] Install the chip body 3 inside the separation ring 2;

[0061] Specifically, the chip body 3 can be bonded to the soldering plate 11 by a chip mounter.

[0062] The window sheet 4 is sealed and connected to the housing 1 and the separation ring 2 at the same time.

[0063] Specifically, the window sheet 4 can be welded together with the housing 1 and the separation ring 2 simultaneously by parallel sealing welding.

[0064] The technical features of the above embodiments may be combined arbitrarily. To make the description concise, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0065] The above-described embodiments only express several implementation methods of the present invention, and the description thereof is relatively specific and detailed, but it cannot be understood as limiting the scope of the present invention. It should be pointed out that, for a person of ordinary skill in the art, several modifications and improvements can be made without departing from the concept of the present invention, and these all belong to the protection scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the attached claims.

Claims

1. A chip structure, characterized in that: The chip structure comprises: shell; A window sheet, wherein the window sheet and the housing are bonded to form a vacuum cavity; A separator ring, which is made of an elastic material and is inserted into the vacuum chamber to separate the vacuum chamber into an outer chamber and an inner chamber that are not connected to each other; two getters, respectively inserted in the outer chamber and the inner chamber, and configured to absorb gas in the outer chamber or the inner chamber; An even number of pressure sensors are arranged in groups of two, and the two pressure sensors in the same group are respectively inserted into the outer chamber and the inner chamber, and are located on both sides of the separation ring, and the pressure sensors are configured to sense the corresponding pressure when the separation ring expands or contracts, and send a signal to start the corresponding getter; and when the pressure inside the outer chamber is greater than the pressure inside the inner chamber, the separation ring is compressed and contracted and sensed by the pressure sensor inside, and the pressure sensor inside sends a signal to start the getter on the outside to absorb the gas inside the outer chamber; when the pressure inside the outer chamber is less than the pressure inside the inner chamber, the separation ring is compressed and expanded and sensed by the pressure sensor outside, and the pressure sensor outside sends a signal to start the getter on the inside to absorb the gas inside the inner chamber; A chip body is inserted into the inner cavity.

2. The chip structure according to claim 1, characterized in that: The chip structure further includes a cooling unit, which is inserted between the chip body and the housing and is configured to be able to cool so that the chip body works at a constant temperature.

3. The chip structure according to claim 2, characterized in that: The cooling unit includes a thermoelectric cooler.

4. The chip structure according to claim 1, characterized in that: There are four pressure sensors, and two groups of pressure sensors are symmetrically arranged about the separation ring.

5. The chip structure according to claim 1, characterized in that: The pressure sensor is a MEMS pressure sensor.

6. The chip structure according to claim 1, characterized in that: An optical window is arranged on the window sheet.

7. The chip structure according to claim 1, characterized in that: The getter is an electrically activated getter.

8. The chip structure according to claim 1, characterized in that: The material of the shell is ceramic.

9. An infrared detector, characterized in that: Comprising the chip structure as described in any one of claims 1 to 8.

10. A processing technology for an infrared detector, characterized in that: Applied to the infrared detector according to claim 9, the processing technology of the infrared detector comprises the following steps: The separation ring, the getter and the pressure sensor are all welded in the cavity of the housing; Installing the chip body inside the separation ring; The window piece is sealed and connected to the housing and the separation ring at the same time.

Images