Novel infrared sensor and processing technology for plating getter in Kovar cap

Abstract

The invention discloses a novel infrared sensor and a processing technology for plating getters in a Kovar cap, and relates to the technical field of infrared detection.The novel infrared sensor comprises a ceramic tube shell, a substrate is connected to the bottom of the inner wall of the ceramic tube shell, a chip is fixedly connected to the bottom of the inner wall of the substrate, the getters are fixedly connected to the left side and the right side of the inner wall of the substrate, and the getters are fixedly connected to the left side and the right side of the inner wall of the substrate. The bottom of the inner wall of the substrate is fixedly connected with a getter, the periphery of the top of the substrate is fixedly connected with a metal layer, the adjacent side of the inner wall of the metal layer is fixedly connected with an AR layer, the top of the outer wall of the AR layer is fixedly connected with a light window, and the top of the outer wall of the light window is provided with a Kovar cap. Compared with a sensor of a traditional structure, the sensor structure has the advantages that the getters are fixed on the two sides and the bottom of the substrate, so that the sensor structure is smaller in size, lower in cost, higher in vacuum degree after packaging and better in chip performance.

Description

Technical Field

[0001] The present invention relates to the technical field of infrared detection, and particularly to a novel infrared sensor and a processing technology for plating getter inside a kovar cap. Background Art

[0002] As the core component of the infrared industrial chain, the performance of an infrared detector directly determines the overall quality of an infrared imaging system. With the rapid development of infrared detector technology and the continuous decline in manufacturing costs, in addition, the application scope of infrared detectors in fields such as security monitoring, power monitoring, medical temperature measurement, intelligent driving, biometric recognition, and the Internet of Things is constantly expanding. Therefore, the cost-effectiveness and reliability of infrared detectors have become increasingly important. Currently, the packaging cost has accounted for more than 50% of the total R & D cost of infrared detectors, which reflects the importance of packaging technology as a research focus in the field of uncooled infrared detectors.

[0003] Sensors with traditional structures usually adopt vacuum packaging technology. Air, moisture, etc. will reduce the heat insulation of sensor elements, resulting in reduced sensitivity, especially for high-sensitivity image sensors used in thermal imagers and thermal imaging cameras. Therefore, a very high vacuum degree is required. To ensure vacuum, strip-shaped getters are usually placed inside. Or, instead of using sheet getters, by expanding the area of the packaging optical window, a thin-film getter is deposited on the optical window. No matter which structure is adopted, space must be reserved for the getter, making the overall structure large in volume and high in cost; due to the relatively small area of the getter, the overall vacuum degree after packaging is poor, further affecting the performance of the entire chip. Summary of the Invention

[0004] To make up for the above deficiencies, the present invention provides a novel infrared sensor and a processing technology for plating getter inside a kovar cap, aiming to further reduce costs, reduce the volume, and improve the performance.

[0005] To achieve the above object, the present invention adopts the following technical scheme: A novel infrared sensor includes a ceramic package. The bottom of the inner wall of the ceramic package is connected with a substrate. The bottom of the inner wall of the substrate is fixedly connected with a chip. Getters are fixedly connected to both the left and right sides of the inner wall of the substrate. The bottom of the inner wall of the substrate is fixedly connected with a getter. A metal layer is fixedly connected to the periphery of the top of the substrate. An AR layer is fixedly connected to an adjacent side of the inner wall of the metal layer. A light window is fixedly connected to the top of the outer wall of the AR layer. A kovar cap is arranged on the top of the outer wall of the light window.

[0006] As a further description of the above technical scheme: The getter is a thin-film type getter.

[0007] As a further description of the above technical scheme: In the middle of the inner wall of the kovar cap, there is a fixedly connected fixing frame.

[0008] As a further description of the above technical solution: At the bottom of the outer wall of the kovar cap, there is a fixedly connected base.

[0009] As a further description of the above technical solution: At the bottom of the outer wall of the base, there is a fixedly connected gasket.

[0010] As a further description of the above technical solution: On the left and right sides of the bottom of the ceramic package, there are multiple fixedly connected pins.

[0011] As a further description of the above technical solution: At the top of the inner wall of the kovar cap, there is a fixedly connected square groove.

[0012] As a further description of the above technical solution: The getter is a thin film type getter.

[0013] A processing technology for plating a getter inside a kovar cap, using laboratory equipment for physical vapor deposition (PVD) for thin film manufacturing: After injecting reaction gas into the vacuum chamber, apply an electrostatic field E to ionize the reaction gas to generate a high-energy Ar+ ion beam; The high-energy ions are directionally bombarded on the surface of the target under the action of electric field acceleration, triggering the sputtering effect of the target atoms / molecules; Among them, the electrically neutral target particles migrate to the surface of the substrate and complete the deposition, finally forming a dense thin film structure.

[0014] As a further preferred solution for the processing technology of plating a getter inside a kovar cap of the present invention, the process flow specifically includes the following steps; Step 1, vacuum preparation: After starting the system, execute in sequence: Turn on the fore pump, start the regeneration valve, activate the cryopump, and open the roughing valve; When the resistance gauge monitors the predetermined threshold vacuum degree, close the roughing valve and the fore pump in sequence; Then open the vent valve to complete the cavity balance, and load the sample tray into the sample chamber; On the fork, restart the fore pump and the roughing valve, observe the compound vacuum degree, and alternately operate the slow pumping valve and the fast pumping valve to pump vacuum; Step 2, heat treatment stage: Open the high valve, set the heating system to 80 - 200 °C, and maintain the vacuum environment in the sample chamber; Step 3, sample transfer: Close the high valve, open the isolation valve, and control the traverse motor to transfer the sample to the sputtering chamber; Step 4, sputtering deposition: Put in the target, activate the heating system; Set the power supply start time, sputtering current parameter of 1 - 5 A, power parameter of 0.3 - 2 kW, and the reaction gas flow rate; After the power supply starts, start timing. After the pre-sputtering cycle is completed, open the baffle, and turn off the heating system for cooling; Step 5, sample extraction: Turn on the roughing pump and the roughing valve, open the isolation valve, and drive the traversing motor into the sputtering chamber; then move the traversing motor to the left. After the lifting motor moves to the lower position, move the traversing motor to the right; then close the isolation valve. Step 6, venting: Close the roughing valve and the roughing pump in sequence, open the venting valve. After the resistance gauge shows that the ambient pressure meets the standard, open the sample chamber door. Finally, close the venting valve and take out the finished sample.

[0015] The present invention has the following beneficial effects: In the present invention, the ceramic package ensures the reliability of component installation. The connection between the substrate and the chip guarantees the stability and precise function of the chip. The getter is fixed on both sides and the bottom of the substrate, effectively removing residual gas and protecting the chip from impurity interference. The metal layer and the AR layer provide conductivity and reduce light reflection respectively, enhancing the light transmittance. The kovar cap ensures the overall airtightness and sealing strength, realizing the vacuum packaging of the chip, reducing the cost, avoiding air and moisture from reducing the heat insulation of the sensor element, and improving the device sensitivity. Compared with the traditional sensor structure, the structure of the present invention removes the space specifically reserved for the getter, making the whole structure more compact and the volume smaller; the reduced volume of the light window and the like brings about a reduction in cost; while the volume is reduced, the area of the getter becomes larger. Therefore, the overall vacuum degree after packaging is better, ensuring the life and performance of the entire chip. Description of the Drawings

[0016] Figure 1 is a perspective view of a novel infrared sensor proposed by the present invention; Figure 2 is an exploded view of the structure of a novel infrared sensor proposed by the present invention; Figure 3 is a sectional view of a novel infrared sensor proposed by the present invention; Figure 4 is a split view of the structure of a novel infrared sensor proposed by the present invention.

[0017] Legend Explanation: 1. Ceramic package; 2. Substrate; 3. Getter; 4. Chip; 5. Metal layer; 6. AR layer; 7. Light window; 8. Kovar cap; 9. Fixing frame; 10. Base; 11. Gasket; 12. Pin; 13. Square groove. Detailed Embodiment

[0018] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0019] Referring to Figure 2 、 Figure 3 and Figure 4 ,an embodiment provided by the present invention is a novel infrared sensor, including a ceramic package 1. At the bottom of the inner wall of the ceramic package 1, a substrate 2 is connected. At the bottom of the inner wall of the substrate 2, a chip 4 is fixedly connected. On both the left and right sides of the inner wall of the substrate 2, getter 3s are fixedly connected. At the bottom of the inner wall of the substrate 2, a getter 3 is also fixedly connected. Around the top of the substrate 2, a metal layer 5 is fixedly connected. On one adjacent side of the inner wall of the metal layer 5, an AR layer 6 is fixedly connected. On the top of the outer wall of the AR layer 6, an optical window 7 is fixedly connected. On the top of the outer wall of the optical window 7, a kovar cap 8 is provided. In the middle of the inner wall of the kovar cap 8, a fixing frame 9 is fixedly connected; Specifically, in the internal structure of the ceramic package 1, a stable connection is adopted between the bottom of its inner wall and the substrate 2, providing a reliable foundation for the installation of subsequent components. The substrate 2 is connected to the chip 4 at the bottom of its inner wall. The chip 4 is a MEMS chip 4, ensuring the stability of the chip 4 during operation. On both the left and right sides of the inner wall of the substrate 2, getter 3s are fixedly connected. The getter is a thin-film getter. The role of the getter 3 is crucial. It can effectively adsorb the residual gas inside the package, creating a purer internal environment and ensuring that the performance of the chip 4 is not interfered by impurity gases. It is worth mentioning that a getter 3 is also fixedly connected to the bottom of the inner wall of the substrate 2, acting together from multiple directions to further enhance the adsorption effect of the internal gas. Around the top of the substrate 2, a metal layer 5 is fixedly connected. The metal layer 5 not only has good electrical conductivity but also plays a key connecting and transitional role in the whole structure. On one adjacent side of the inner wall of the metal layer 5, the AR layer 6 is fixedly connected. The AR layer 6 is an antireflection layer, which can effectively reduce the reflection of light during transmission and improve the light transmittance. On the top of the outer wall of the AR layer 6, the optical window 7 is firmly fixedly connected. The optical window 7 is an important channel for optical signals to enter and exit, and its material and process can ensure the efficient transmission and stability of light. On the top of the outer wall of the optical window 7, a kovar cap 8 is provided. The kovar cap 8 has good airtightness and sealing strength. In the middle of the inner wall of the kovar cap 8, a fixing frame 9 is fixedly connected. The fixing frame 9 can further protect and fix the internal components, preventing the internal components from shifting under the influence of external vibration factors, thus comprehensively ensuring the stability of the internal structure of the entire ceramic package 1 and the reliability of its performance.

[0020] Referring to Figure 1 、 Figure 2 and Figure 4 ,at the bottom of the outer wall of the kovar cap 8, a base 10 is fixedly connected. At the bottom of the outer wall of the base 10, a gasket 11 is fixedly connected. On the left and right sides of the bottom of the ceramic package 1, a plurality of pins 12 are fixedly connected. On the top of the inner wall of the kovar cap 8, a square groove 13 is fixedly connected; Specifically, multiple pins 12 on the left and right sides of the bottom of the ceramic package 1, as electrical connection interfaces, are responsible for connecting to the external circuit, introducing external electrical signals into the package, and providing the required working voltage and signal input for the chip 4. The base 10 connected to the bottom of the outer wall of the kovar cap 8 further stabilizes the structure, and the gasket 11 at the bottom of the outer wall of the base 10 can play a buffering and insulating role, enhancing the stability and safety of the entire device during installation and use. The square groove 13 fixed to the top of the inner wall of the kovar cap 8 is used to accommodate and fix the components related to the optical window 7, further optimizing the overall function from the structural layout. Each component is closely matched to meet the working requirements of the ceramic package 1 in terms of electrical, optical, and structural sealing.

[0021] Working principle: The infrared image sensor chip 4 is packaged using vacuum packaging technology. Air and moisture will reduce the heat insulation of the sensor components, resulting in reduced sensitivity. Especially for the high-sensitivity image sensors used in thermal imagers and thermal imaging cameras, a very high vacuum degree is required. A large number of chips 4 can be vacuum-packaged in large quantities. The bottom of the inner wall of the ceramic package 1 is firmly connected to the substrate 2, serving as the installation foundation for the components. The chip 4 is connected to the bottom of the inner wall of the substrate 2 to ensure its stable operation. Getters 3 are fixed to both sides and the bottom of the inner wall of the substrate 2 to adsorb the residual gas in the tube, purify the internal environment, and improve the performance of the chip 4. A metal layer 5 is fixed around the top of the substrate 2 to play a role in connection transition and conduction. The AR layer 6 is connected to the adjacent side of the inner wall of the metal layer 5 to reduce light reflection and improve the light transmittance. The optical window 7 is connected to the top of the AR layer 6 as an optical signal channel to ensure efficient and stable light transmission. A kovar cap 8 is provided at the top of the optical window 7, which has good airtightness and sealing strength. The main packaging form of the infrared detector is ceramic packaging because it can achieve the advantages of high performance, low cost, small volume, and light weight. The volume is reduced by 40% without changing the height, almost half of the volume, reducing the cost. The area of the getter 3 also increases accordingly. Air and moisture will reduce the heat insulation of the sensor components, improve the product sensitivity, and increase the required area for evaporating the getter 3 on the outer ring of the transmissive cover. Secondly, the volume of the overall packaging structure is effectively reduced. Thirdly, the vacuum sealing performance is improved, enabling the vacuum packaging of a large number of chips 4. By optimizing the use of materials, the amount of germanium material is significantly reduced, thus achieving a significant cost reduction.

[0022] A processing technology for coating getters inside Kovar caps. The equipment used for coating getters inside Kovar caps is a pioneering laboratory device for physical vapor deposition (PVD) in thin film manufacturing. This equipment realizes material deposition through the following physical processes: after injecting reaction gas into the vacuum chamber, an electrostatic field E is applied to ionize the reaction gas to generate a high-energy Ar+ ion beam. These high-energy ions are directed to bombard the surface of the target material under the action of electric field acceleration, triggering the sputtering effect of the target atoms / molecules. Among them, the neutral target particles migrate to the substrate surface and complete the deposition, finally forming a dense thin film structure. Using a laboratory device for physical vapor deposition PVD in thin film manufacturing: after injecting reaction gas into the vacuum chamber, an electrostatic field E is applied to ionize the reaction gas to generate a high-energy Ar+ ion beam; the high-energy ions are directed to bombard the surface of the target material under the action of electric field acceleration, triggering the sputtering effect of the target atoms / molecules; among them, the neutral target particles migrate to the substrate surface and complete the deposition, finally forming a dense thin film structure.

[0023] The process flow specifically includes the following steps; Step 1, vacuum preparation: After starting the system, perform the following operations in sequence: turn on the fore pump, start the regeneration valve, activate the cryopump, and open the roughing valve; when the resistance gauge monitors the predetermined threshold vacuum degree, close the roughing valve and the fore pump in sequence; then open the bleed valve to complete the chamber balance, and load the sample tray into the sample chamber; on the fork, restart the fore pump and the roughing valve, observe the composite vacuum degree, and alternately operate the slow pump valve and the fast pump valve to evacuate the vacuum; Step 2, heat treatment stage: Open the high valve, set the heating system to 80 - 200 °C, and maintain the vacuum environment in the sample chamber; Step 3, sample transfer: Close the high valve, open the isolation valve to control the traverse motor to transfer the sample to the sputtering chamber; Step 4, sputtering deposition: Place the target material, activate the heating system; set the power supply start time, sputtering current parameter of 1 - 5 A, power parameter of 0.3 - 2 kW, and the reaction gas flow rate; start timing after the power supply is started, open the baffle after the pre-sputtering cycle is completed, and turn off the heating system for cooling; Step 5, sample removal: Open the fore pump, the roughing valve, open the isolation valve to drive the traverse motor into the sputtering chamber; then move the traverse motor to the left, move the lifting motor to the lower position and then move the traverse motor to the right; then close the isolation valve; Step 6, venting: Close the roughing valve and the fore pump in sequence, open the bleed valve, open the sample chamber door after the resistance gauge shows that the ambient pressure meets the standard, and finally close the bleed valve and take out the finished sample.

[0024] Finally, it should be noted that the above are only 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 skilled in the art can still modify the technical solutions described in the foregoing embodiments, or perform equivalent replacements for some of the technical features. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A novel infrared sensor, comprising a ceramic tube shell (1), characterized in that: The bottom of the inner wall of the ceramic tube shell (1) is connected to a substrate (2), the bottom of the inner wall of the substrate (2) is fixedly connected to a chip (4), the left and right sides of the inner wall of the substrate (2) are fixedly connected to a getter (3), the bottom of the inner wall of the substrate (2) is fixedly connected to the getter (3), the top of the substrate (2) is fixedly connected to a metal layer (5), one side of the inner wall adjacent to the metal layer (5) is fixedly connected to an AR layer (6), the top of the outer wall of the AR layer (6) is fixedly connected to a light window (7), and the top of the outer wall of the light window (7) is provided with a Kovar cap (8).

2. A novel infrared sensor according to claim 1, characterized in that: A fixing frame (9) is fixedly connected to the middle portion of the inner wall of the Kovar cap (8).

3. A novel infrared sensor according to claim 1, characterized in that: A base (10) is fixedly connected to the bottom of the outer wall of the Koval cap (8).

4. A novel infrared sensor according to claim 3, characterized in that: A gasket (11) is fixedly connected to the bottom of the outer wall of the base (10).

5. The novel infrared sensor according to claim 1 is characterized in that: A plurality of pins (12) are fixedly connected to the left and right sides of the bottom of the ceramic tube shell (1).

6. A novel infrared sensor according to claim 1, characterized in that: A square groove (13) is fixedly connected to the top of the inner wall of the Koval cap (8).

7. A novel infrared sensor according to claim 1, characterized in that: The getter (3) is a thin film type getter.

8. A process for processing a getter plated inside a Kovar cap according to any one of claims 1 to 7, characterized in that: Laboratory equipment used for physical vapor deposition (PVD) in thin film manufacturing is used: after the reaction gas is injected into the vacuum chamber, an electrostatic field E is applied to ionize the reaction gas to generate a high-energy Ar+ ion beam; the high-energy ions bombard the target surface in a direction under the acceleration of the electric field, causing the target atoms / molecules to undergo sputtering; the electrically neutral target particles migrate to the substrate surface and complete deposition, eventually forming a dense thin film structure.

9. The process for coating a getter in a kovar cap according to claim 8, characterized in that: The process specifically includes the following steps: Step 1, vacuum preparation: After starting the system, perform the following steps in sequence: start the foreline pump, start the regeneration valve, activate the cryopump, and open the roughing valve; when the resistance gauge detects the predetermined threshold vacuum degree, close the roughing valve and the foreline pump in sequence; then open the vent valve to complete the cavity balance and load the sample tray into the sample chamber; on the fork, restart the foreline pump and the roughing valve, observe the composite vacuum degree, and alternately operate the slow pumping valve and the fast pumping valve to evacuate the vacuum; Step 2, heat treatment stage: open the high valve, set the heating system to 80-200°C, and maintain the vacuum environment of the sample chamber; Step 3, sample transfer: close the high valve, open the isolation valve to control the traverse motor to transfer the sample to the sputtering chamber; Step 4, sputtering deposition: put in the target material and activate the heating system; set the power on time, sputtering current parameter 1-5A, power parameter 0.3-2 kW and reaction gas flow rate; start timing after the power is turned on, open the baffle after the pre-sputtering cycle is completed, and turn off the heating system for cooling; Step 5, sample removal: open the foreline pump, the roughing valve, and the isolation valve to drive the traverse motor into the sputtering chamber; Then move the traverse motor to the left, and after the upgrade motor moves to the lower position, move the traverse motor to the right; then close the isolation valve; Step 6, venting: close the roughing valve and the front pump in sequence, open the venting valve, open the sample chamber door after the resistance gauge shows that the ambient pressure meets the standard, and finally close the venting valve and take out the finished sample.

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