Method for manufacturing a detector chip

Abstract

The application provides a preparation method of a detector chip. After a window sheet is bonded with a device wafer to form a vacuum cavity corresponding to each detection unit in a detector array, laser is irradiated onto a getter in the vacuum cavity through the window sheet. The energy provided by the laser activates the getter, so that the getter can regain the gettering ability. In the process of activating the getter, since the laser only irradiates the area where the getter is located, the energy generated by the laser will not damage the structure of the detection unit, and the phenomenon of solder overflow during the activation process can be effectively avoided, which is beneficial to improve the reliability of the detector chip.

Description

Technical Field

[0001] This application relates to the field of semiconductor technology, and in particular to a method for fabricating a detector chip. Background Technology

[0002] Micro-Electro-Mechanical Systems (MEMS) technology, as an emerging microfabrication technology, has begun to be applied in various fields. It integrates functions such as information acquisition, processing, and execution, and possesses advantages such as miniaturization, intelligence, operability, integrability, good process compatibility, and low cost. Therefore, MEMS technology also has very broad application prospects in the field of infrared detection technology, providing a new avenue for research in this area. Applying MEMS technology to the development of uncooled infrared detectors can enable devices to develop towards high reliability, miniaturization, intelligence, high-density array integration, low cost, and mass production capabilities. It is also possible to use this technology to fabricate uncooled infrared detectors with entirely new mechanisms.

[0003] MEMS infrared detector wafer-level packaging uses a wafer as the processing object, simultaneously packaging numerous detector units on the wafer to form detector chips, and then further aging and testing on the wafer before dividing them into individual detector chips for packaging. Compared with traditional packaging methods, wafer-level packaging has the advantages of high efficiency, short cycle time, and low cost. The vacuum level inside the infrared detector vacuum chamber formed during wafer-level packaging has a significant impact on its performance. Therefore, to ensure the detector's excellent performance, the internal vacuum level of the detector must be strictly controlled. Due to the outgassing phenomenon of the internal materials of the detector, the internal vacuum level will decrease during long-term use. Therefore, to ensure that the detector performance is not affected, a getter needs to be placed inside the vacuum chamber to maintain its vacuum level.

[0004] In the wafer-level packaging process of infrared detectors, gases such as H2O, CO2, and hydrocarbons are adsorbed on the surface of the getter exposed to the atmosphere. Therefore, in order to ensure the vacuum level inside the detector's vacuum chamber, the getter inside the vacuum chamber needs to be activated to restore its getter performance.

[0005] Currently, the activation methods for getters in detectors mainly include high-temperature heating, high-frequency induced current activation, or thermal radiation activation. Among these, high-temperature heating can easily cause thermal failure of the MEMS structure (the pixel area of ​​the detector), and can also lead to encapsulation failure, reduced vacuum, and other problems. Furthermore, the solder is susceptible to balling due to high temperatures, which can also affect the detector. High-frequency induced current activation can easily cause microcircuit losses, leading to electrical or magnetic failures in the MEMS structure. Clearly, current getter activation methods are easily affected by material properties and process windows, resulting in insufficient getter activation, leading to insufficient vacuum in the detector's vacuum chamber and ultimately detector failure. In addition, heating activation is inefficient, difficult to control precisely, and can easily damage the detector. Summary of the Invention

[0006] To address the existing technical problems, this application provides a method for fabricating a detector chip that can avoid damage to circuits and devices during getter activation.

[0007] A method for fabricating a detector chip, comprising:

[0008] A device wafer with a detector array is bonded to a corresponding window, and a vacuum cavity is formed between the device wafer and the window, which corresponds to each detector in the detector array. Each vacuum cavity is provided with a corresponding getter.

[0009] A laser is used to irradiate the area of ​​the getter in each of the vacuum chambers through the window, and the laser is absorbed by the getter in the vacuum chamber to activate the getter in each of the vacuum chambers.

[0010] In some embodiments, the laser is a continuous laser.

[0011] In some embodiments, the preparation method further includes:

[0012] Based on the getter rate and getter volume in each of the vacuum cavities, the output power and irradiation time corresponding to the laser irradiating the window are set.

[0013] In some embodiments, the window is provided with markings corresponding to each of the vacuum cavities, and the preparation method further includes:

[0014] Based on the identification results of the markers, the position information of the getter in the vacuum cavity corresponding to each of the detectors is determined;

[0015] Based on the position information of the getter in each of the vacuum chambers, the laser is controlled to be aligned with the area of ​​the getter in each of the vacuum chambers.

[0016] In some embodiments, bonding the device wafer with the detector to the corresponding window includes:

[0017] After aligning the device wafer with the window, it is placed in the bonding machine;

[0018] The bonding cavity formed between the aligned device wafer and the window is subjected to vacuum treatment.

[0019] After the vacuum level in the bonding cavity meets the set conditions, the bonding cavity is preheated and vented. The preheating temperature is lower than the melting point of the solder ring used to bond the device wafer and the window plate.

[0020] After the duration of the preheating exhaust treatment reaches a first set time, the temperature of the bonding cavity is controlled to rise from the preheating temperature to the bonding temperature to melt the solder ring used to bond the device wafer and the window piece, and the window piece is connected to the device wafer solder through the solder ring used to bond the device wafer and the window piece by applying pressure.

[0021] After the bonding temperature duration reaches a second set time, cooling and depressurization processes are performed to form the vacuum cavity consisting of the solder ring, the window, and the device wafer.

[0022] In some embodiments, before bonding the device wafer with the detector to the corresponding window, the fabrication method further includes:

[0023] A getter is fabricated on a non-device fabrication area on the side of the device wafer where the detector is fabricated, or on a blind region of the detector.

[0024] In some embodiments, the distance between the detection unit of each detector and the corresponding getter is determined based on the output power of the laser and the time it irradiates the getter.

[0025] In some embodiments, the laser is an infrared laser or an X-ray laser.

[0026] In some embodiments, before bonding the device wafer with the detector to the corresponding window, the fabrication method further includes:

[0027] A getter is fabricated in the non-optical window region on the side of the window sheet opposite to the device wafer;

[0028] The laser is an infrared laser.

[0029] In some embodiments, the preparation method further includes:

[0030] After activating the getter in each of the vacuum chambers, the detector array is tested for performance, and based on the test results, the target detectors that need to be reactivated with getter are determined.

[0031] The laser is used to irradiate the area of ​​the getter in the vacuum cavity of the target detector through the window to reactivate the getter in the vacuum cavity of the target detector.

[0032] As can be seen from the above, in the fabrication method of the detector chip provided in this application, after bonding a window sheet to a device wafer to form a vacuum cavity corresponding to each detection unit in the detector array, a laser is then used to irradiate the getter in the vacuum cavity through the window sheet. The energy provided by the laser to the getter activates the getter, enabling it to regain its gettering ability. During the activation process, since the laser only irradiates the area where the getter is located, the energy generated by the laser will not damage the structure of the detection unit. It also effectively avoids solder ball overflow during the activation process, which is beneficial to improving the reliability of the detector chip. Attached Figure Description

[0033] The accompanying drawings are for illustrative purposes only and are not intended to limit the invention. Furthermore, the same reference numerals denote the same parts throughout the drawings. In the drawings:

[0034] Figure 1 This is a schematic flowchart of a method for fabricating a detector chip according to some embodiments of this application;

[0035] Figure 2 This is a schematic diagram of the structure of the device formed during laser activation in the fabrication method of the detector chip provided according to some embodiments of this application;

[0036] Figure 3 A top view of the device is formed during laser activation in the fabrication method of the detector chip provided in some embodiments of this application;

[0037] Figure 4 This is a schematic diagram illustrating the principle of laser activation of the getter during the fabrication method of a detector chip according to some embodiments of this application;

[0038] Figure 5This is a schematic flowchart illustrating the bonding process between a window and a device wafer in the fabrication method of a detector chip according to some embodiments of this application.

[0039] Figure 6 This is a schematic diagram of the device structure after the window and the device wafer are aligned and before bonding during the fabrication process of the detector chip according to some embodiments of this application;

[0040] Figure 7 This is a schematic diagram of the device structure after the window is aligned with the device wafer and before bonding during the fabrication process of the detector chip according to some other embodiments of this application;

[0041] Figure 8 This is a schematic diagram of the structure of the device formed during laser activation in the fabrication method of the detector chip provided according to other embodiments of this application.

[0042] Component symbol explanation: 1. Window plate; 2. Solder ring; 3. Device wafer; 4. Getter; 5. Vacuum cavity; 6. Probe unit; 7. Bonding cavity. Detailed Implementation

[0043] The technical solution of this application will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0044] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used herein in the specification of this application is for the purpose of describing particular embodiments only and is not intended to limit the ways in which this application may be implemented. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0045] In the description of this application, it should be understood that the terms "center," "upper," "lower," "front," "rear," "left," "right," "vertical," "row," "top," "bottom," "inner," and "outer," etc., indicating the orientation or positional relationship, are based on the orientation or positional relationship shown in the accompanying drawings and are used only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation on this application. In the description of this application, unless otherwise stated, "a plurality of" means two or more.

[0046] In the description of this application, it should be noted that, unless otherwise expressly specified and limited, the terms "installation," "connection," and "joining" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal communication between two components. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.

[0047] To overcome the adverse effects of existing getter activation methods on detector performance, this application provides a method for fabricating a detector chip using laser activation to activate the getter. During the detector chip fabrication process, after forming a vacuum cavity, laser activation is performed on the getter location, avoiding structural damage to the detector and effectively preventing excessive melting of solder at high temperatures, which can cause ball overflow. The detector chip in this application embodiment can be an uncooled infrared detector chip. The following will combine... Figures 1 to 8 The fabrication methods of the detector chips provided in the various embodiments of this application will be further described.

[0048] Please refer to Figure 1 As shown, this is a schematic flowchart of the fabrication method of the detector chip according to an embodiment of this application. In the fabrication method of the detector chip according to this embodiment, the schematic diagram of the device structure before bonding the window to the device wafer is shown below. Figure 6 or Figure 7 As shown in the diagram, the corresponding device structure formed during laser activation of the getter is as follows: Figure 2 or Figure 8 As shown. In this embodiment, the fabrication method of the detector chip includes S02 and S04, which are described in detail below.

[0049] S02: The device wafer with the detector array is bonded to the corresponding window, and a vacuum cavity is formed between the device wafer and the window, which corresponds to each detector in the detector array. Each vacuum cavity is equipped with a corresponding getter.

[0050] refer to Figure 2 , 6 7 and / or Figure 8As shown, the detector array is an array composed of multiple MEMS structures, each of which is a detector unit 6 (also called an infrared sensitive pixel unit) fabricated using MEMS technology to detect infrared radiation. The device wafer 3 can be a silicon wafer with detector readout circuitry. The readout circuitry in device wafer 3 is connected to the corresponding detector unit 6 fabricated on device wafer 3 to read infrared detection signals. The window 1 is an optical window corresponding to the detector array on device wafer 3. This window 1 can be a window wafer corresponding to device wafer 3, with optical window units corresponding to each detector unit 6 in the detector array. Each optical window unit and its corresponding detector unit 6 constitute a vacuum cavity 5. Therefore, the number of detector units 6 in the detector array on device wafer 3 corresponds to the number of optical window units on the window wafer, and the number of vacuum cavities 5 formed after bonding device wafer 3 and the window wafer is equal to the number of vacuum cavities 5 formed. Each vacuum cavity 5 contains a corresponding getter 4 and a detector unit 6. Window 1 can also be multiple independent window pieces that correspond to each detection unit 6 in the detector array. That is, window 1 is composed of independent window pieces in a number corresponding to the number of detection units 6 in the detector array. Each independent window piece is bonded to the corresponding position on the device wafer 3 to serve as the optical window of the corresponding detection unit 6 in the detector array on the device wafer 3.

[0051] A getter 4 is installed in the vacuum chamber 5. After activation, the getter 4 can absorb gases within the vacuum chamber 5. It should be noted that the vacuum chamber 5 does not refer to an absolute vacuum, but rather a vacuum chamber whose vacuum level meets the set vacuum conditions. The getter 4 can be located in the non-optical window area of ​​the window 1, or in a non-device fabrication area on the device wafer 3, or in a blind cell area of ​​the detector. The non-optical window area refers to the area of ​​the window 1 that is not used to transmit infrared light for detection by the corresponding detection unit 6; that is, the getter 4 cannot block the detection light from the detection unit 6 from reaching the detection unit 6. A blind cell, also known as an invalid pixel, is a dead pixel or an overheated pixel generated during the production process of the detector array. A dead pixel is a pixel with a responsivity less than 1 / 10 of the average responsivity, and an overheated pixel is a pixel with a noise voltage greater than 10 times the average noise voltage.

[0052] In some embodiments, a solder ring 2 may be provided on the window 1. After the window 1 and the device wafer 3 are bonded together by the solder ring 2, the window 1, the solder ring 2 and the device wafer 3 constitute a vacuum cavity 5. Figure 2 Top view of the device structure shown. Figure 3 As shown. It should be noted that, Figure 2 The diagram only shows the structure corresponding to one detector on device wafer 3. Figure 3 Detection unit 6 is not shown in the diagram. Figure 2In this configuration, the getter 4 is fabricated on the non-device fabrication area on the side of the device wafer 3 where the detector array is located. Specifically, the getter 4 is situated around the detector unit 6 (MEMS structure) and at a certain distance from it. A solder ring 2 is provided on the window 1, positioned at the edge of the area of ​​the window 1 opposite to the getter 4 and the detector unit 6. After the window 1 is bonded to the device wafer 3 via the solder ring 2, a vacuum cavity 5 is formed.

[0053] S04: A laser is used to irradiate the area of ​​the getter in each vacuum chamber through the window and is absorbed by the getter in the vacuum chamber to activate the getter in each vacuum chamber.

[0054] like Figure 2 and Figure 3 As shown, in some embodiments, a laser is used to irradiate the vacuum cavity 5 from the region of the window 1 corresponding to the getter 4, reaching the getter 4 and being absorbed by it. After the laser reaches the getter 4, it continuously gains energy, and the passivation film on the surface of the getter 4 is gradually removed, causing the getter 4 to regain its activity, thus completing the activation of the getter 4. Once activated, the getter 4 can regain its gettering ability. In the fabrication process of the detector chip provided in this application embodiment, after the window 1 and the device wafer 3 are bonded to form the vacuum cavity 5, a schematic diagram of the principle of using a laser to activate the getter 4 in the vacuum cavity 5 is shown below. Figure 4 As shown. The laser in S04 refers to the laser that can pass through window 1 and be absorbed by getter 4 after passing through window 1. After the getter 4 absorbs the laser, it gains energy, causing H2O (water molecules), CO2 (carbon dioxide molecules), and hydrocarbons within the getter 4 to gradually desorb from its surface. The oxygen element in the metal oxide constituting the getter 4 mainly leaves the surface of the getter 4 by diffusion inwards. The surface of the getter 4 transforms from an oxidized state to a near-metallic or metallic state, thereby restoring the getter 4 surface to its gettering capacity.

[0055] As can be seen from the above, in the method for fabricating the detector chip provided in this application embodiment, after bonding the window 1 to the device wafer 3 to form a vacuum cavity 5 corresponding to each detection unit 6 in the detector array, a laser is then used to irradiate the getter 4 in the vacuum cavity 5 through the window 1. The energy provided by the laser to the getter 4 activates the getter 4, enabling it to regain its gettering capability. During the activation process of the getter 4, since the laser only irradiates the area where the getter 4 is located, the energy generated by the laser will not damage the structure of the detection unit 6, and the phenomenon of solder ball overflow can also be effectively avoided, which is beneficial to improving the reliability of the detector chip.

[0056] In some embodiments, window 1 is a semiconductor window coated with an infrared antireflection film. The semiconductor window may be a germanium window made of germanium or a silicon window made of silicon. The semiconductor window coated with the infrared antireflection film allows the light to be detected by the detector chip to pass through. In S04, to improve the activation efficiency of the getter 4, the output power of the laser in S04 needs to meet a set output power condition. Generally, the output power of the laser generating the laser in S04 needs to reach a set output power, such as 200-500W. To avoid damage to the getter 4 when a high-power laser irradiates it, S04 further employs a continuous laser with a continuous output mode to irradiate the getter 4, thereby activating the getter 4 without causing damage.

[0057] In some embodiments, the method for fabricating the detector chip further includes: setting the output power and irradiation time of the laser irradiating the window 1 according to the getter 4's getter rate and getter volume in each vacuum cavity 5 formed in S02. The getter rate of the getter 4 is determined by the constituent material of the getter 4, and the getter volume of the getter 4 is the total amount of gas that the getter 4 can absorb. Once the material of the getter 4 is determined, the larger the required total getter volume, the greater the energy required to activate the getter 4, and the output power and irradiation time required to irradiate the getter 4 need to meet the activation energy requirements of the getter 4.

[0058] In the fabrication method of the detector chip according to the embodiments of this application, it is necessary to activate the getter 4 by aligning it with a laser in the region where the getter 4 is located. Therefore, the fabrication method of the detector chip according to the embodiments of this application also includes a step of aligning the laser with the getter 4. In some embodiments, in order to facilitate precise alignment of the window 1 with the device wafer 3, the window 1 is provided with markings corresponding to each detection unit 6 in the detector array provided on the device wafer 3. Figure 2 , 6(The mark is not shown in sections 7 and 8). That is, based on the position of each mark, the range of the area where each detector is located on each device wafer 3 can be determined. It should be noted that each detector unit 6, the corresponding vacuum cavity 5, and the corresponding getter 4 in the detector array on device wafer 3 constitute a detector. Therefore, multiple detectors are actually arranged on device wafer 3, and the location area of ​​each detector is marked on window 1. Therefore, in some embodiments, the specific steps for aligning the laser with the getter 4 in S04 can be: based on the identification result of the marks on window 1, determine the position information of the getter 4 in the vacuum cavity 5 corresponding to each detector, and then, based on the position information of the getter 4 in each vacuum cavity 5, control the laser to align with the area of ​​the getter 4 in each vacuum cavity 5. Specifically, the laser device used to generate the laser in S04 has an identification system that can identify the marks on the window 1 to determine the position area of ​​each detector. Since the positions of the getter 4 and the detection unit 6 in their respective detectors are fixed, the position information of each detector can be determined based on the identification results obtained from identifying the marks. Then, based on the position information of the corresponding detectors, the position information of the getter 4 in the corresponding vacuum cavity 5 can be determined. After the laser device identifies the marks on the window 1, it can obtain the position information of the getter 4. Then, based on the position information of the getter 4, it controls the laser probe of the laser device to move horizontally (x-axis direction) and / or vertically (y-axis direction) to the position of the getter 4 that needs to be activated. Then, it emits a laser that can pass through the window 1, be aimed at the area where the getter 4 is located, and be absorbed by the getter 4. Furthermore, based on the performance of the getter 4 (including the getter rate and getter volume), it determines the output power of the laser irradiating the area where the getter 4 is located and the duration of laser irradiation of the getter 4.

[0059] Please refer to Figure 5 The diagram shown illustrates the bonding process between device wafer 3 and window 1 according to an embodiment of this application. In this embodiment, S02 further includes S021, S022, S023, S024, and S025.

[0060] S021: After aligning the device wafer with the window, place it in the bonding machine.

[0061] In this embodiment, the window 1 can be a window wafer, and the window wafer is provided with marks corresponding to the detectors fabricated on the device wafer 3. Based on the position of the corresponding marks, the window areas of the window wafer can be aligned with the corresponding detector areas in the device wafer 3. In this embodiment, the edges of the window areas corresponding to the window wafer and the device wafer 3 are provided with solder rings 2, that is, the solder rings 2 are pre-fabricated on the window 1 before performing S021. In other embodiments, the solder rings 2 can also be pre-fabricated at the corresponding positions on the device wafer 3 before performing S021. The shape of the solder rings 2 is not limited in this application, and any shape of solder ring that can form a closed vacuum cavity 5 with the window 1 and the device wafer 3 after subsequent bonding is completed is acceptable.

[0062] S022: Vacuum treatment is performed on the bonding cavity formed between the aligned device wafer and the window.

[0063] Since the getter 4 has a limited gas absorption capacity, in order to ensure that the vacuum level of the detector's vacuum cavity 5 meets the device performance requirements, a vacuum process is required after S021 to evacuate the bonding cavity 7 formed between the aligned device wafer 3 and the window 1. The structural schematic diagrams of the device structure formed according to the detection chip fabrication method provided in this application embodiment after aligning the device wafer 3 and the window 1 but before bonding is completed are shown below. Figure 6 and Figure 7 As shown. Figure 6 and Figure 7 The difference is that the position of getter 4 is different. Figure 6 Getter 4 is disposed on wafer device 3, in Figure 7 Getter 4 is disposed on window 1. After aligning window 1 with device wafer 3, a bonding cavity 7 is formed between them. After the bonding process is completed, the bonding cavity 7 forms the aforementioned vacuum cavity 5.

[0064] S023: After the vacuum level in the bonding cavity meets the set conditions, the bonding cavity is preheated and vented. The preheating temperature is lower than the melting point of the solder ring used to bond the device wafer and the window plate.

[0065] The vacuuming of the bonding cavity 7 needs to be determined based on the maximum absorption capacity of the getter 4. That is, after the vacuuming step in S022, the vacuum level inside the bonding cavity 7 must meet a set condition. This set condition can refer to a specific vacuum level or a range of vacuum levels, and its specific value can be set according to the maximum absorption capacity of the getter 4. In some embodiments, the vacuuming process in S022 can control the vacuum level inside the bonding cavity 7 to 10. -1 Up to 10 -6After mbar, a preheating and venting process using S023 is performed. This preheating and venting process further removes the remaining gas in the bonding cavity 7 by preheating and baking. For example... Figure 6 and Figure 7 As shown, during the preheating and venting process, a large amount of material on the surface of the device wafer 3 is released and gradually discharged from the bonding cavity 7 with the airflow, ensuring a high vacuum level in the vacuum cavity 5 of the subsequent detector. Since the heating temperature is set below the melting point of the solder ring 2 during the preheating and venting process, the solder ring 2 does not melt. In some embodiments, the preheating temperature during the preheating and venting process is between 150°C and 300°C, and the duration of the preheating and venting process generally reaches a set time (first set time), such as 40 min to 100 min.

[0066] S024: After the duration of the preheating and exhaust treatment reaches the first set time, the temperature of the bonding cavity 7 is controlled to rise from the preheating temperature to the bonding temperature to melt the solder ring 2, and the window 1 is connected to the device wafer 3 by the solder ring 2 through the solder ring 2 by pressurization.

[0067] After the preheating and venting process has lasted for a first set time (40 min to 100 min), the heating temperature needs to be further increased so that the ambient temperature of the solder ring 2 rises from the preheating temperature to the bonding temperature to melt the solder ring 2. The heating temperature in S023 is lower than the melting point of the solder ring 2, while the heating temperature in S024 is higher than the melting point of the solder ring 2. In some embodiments, the bonding temperature in S024 can generally be set to 200°C to 400°C to melt the solder ring 2. After the temperature stabilizes at the required bonding temperature, the solder ring 2 located between the window 1 and the device wafer 3 is further pressurized, thereby pressurizing the window 1 to be soldered to the device wafer 3 through the solder ring 2.

[0068] S025: After the bonding temperature duration reaches the second set time, cooling and depressurization are performed to form a vacuum cavity consisting of a solder ring, a window, and a device wafer.

[0069] After the bonding temperature reaches the set temperature, the duration of this bonding temperature is maintained for a second set time. While the bonding temperature is maintained at the set temperature, a pressure of 500N to 5000N is continuously applied to the solder ring 2 between the window 1 and the device wafer 3. After the bonding temperature duration reaches the second set time, the ambient temperature of the solder ring 2 is cooled. Once the ambient temperature of the solder ring 2 is below the set cooling temperature, the applied pressure is removed. The second set time is typically 3 to 20 minutes, and the set cooling temperature is typically below 60°C.

[0070] After bonding between window 1 and device wafer 3 is completed, device wafer 3 with window 1 bonded is removed from the bonding machine and placed in a laser device for activation of getter 4. The laser device is equipped with an optical recognition system, which identifies the marks on window 1 to define the range of each detector on each device wafer 3. Under the control of the laser device's operating program, the laser beam translates along the x and y directions according to the specified position (the location of the getter 4 to be activated), accurately locating the area where the getter 4 is located for continuous irradiation. The laser passes through window 1 to reach getter 4, which continuously absorbs infrared light and converts it into heat energy, causing its temperature to rise. The heat is rapidly conducted internally to the surface of getter 4, thereby gradually removing its surface passivation film and re-exposing its activity, thus regaining its getter capability.

[0071] In some embodiments, prior to S02, the method for fabricating the detector chip according to the embodiments of this application further includes a getter fabrication step. In some embodiments, such as Figure 2 and Figure 6 As shown, the getter 4 is fabricated on the device wafer 3. Specifically, the getter 4 is fabricated in a non-device fabrication area on the side of the detector unit 6 on the device wafer 3 where the detector is fabricated. In other embodiments, the getter 4 can also be fabricated on the blind cell region of the detector on the device wafer 3 to serve as a light-shielding material for the detector. The specific steps for fabricating the getter 4 can be as follows: first, photoresist is coated and patterned on the device wafer using photolithography; then, the getter is deposited at the corresponding position using physical vapor deposition to form the getter 4.

[0072] In the embodiment where getter 4 is fabricated on device wafer 3 (corresponding to...) Figure 2 and Figure 6 In step S04, the laser used can be either an infrared laser or an X-ray laser. In some embodiments, the wavelength range of the infrared laser is 800nm ​​to 2000nm, and the wavelength range of the X-ray laser is 1nm to 10nm. The infrared laser activates the getter 4 in the form of heat, while the X-ray laser activates it in the form of electromagnetic energy. When activating the getter 4 with an infrared laser, the laser directly targets the area containing the getter 4 without irradiating the detection unit 6, thus preventing damage to the detection unit 6 during activation. Similarly, when activating the getter 4 with an X-ray laser, the X-ray laser transfers energy to the getter 4 in the form of electromagnetic energy, preventing any temperature increase in other areas of the detector and effectively avoiding damage to the device during activation.

[0073] In some embodiments, during the activation of the getter 4 using an infrared laser, to avoid damage to the detection unit 6 adjacent to the getter 4 caused by the heat generated during the heat transfer process of the infrared laser, the fabrication method of the detector chip provided in this application further includes: determining the distance between the getter 4 and the corresponding detection unit 6 of each detector based on the output power of the laser and the time it irradiates the getter 4. This step is performed before fabricating the getter 4; that is, after determining the distance between the detection unit 6 of each detector and the corresponding getter 4 based on the output power of the laser and the time it irradiates the getter 4, the patterning processing of the photoresist in the fabrication of the getter 4 is performed based on this distance.

[0074] In other embodiments, such as Figure 7 and 8 As shown, the getter 4 can also be fabricated on the window 1. Specifically, before performing S02, the fabrication method of the detector chip provided in this application further includes: fabricating the getter 4 in the non-optical window region on the side of the window 1 opposite to the device wafer 3. The non-optical window region has been explained above and will not be described again here. Figure 7 As shown, before S02, solder is first deposited on window 1 using photolithography to form solder ring 2. Then, photolithography is used to coat and pattern the photoresist on window 1, exposing the non-optical window area of ​​window 1. Next, getter 4 is deposited onto the non-optical window area using physical vapor deposition, thus completing the getter 4 deposition. The non-optical window area refers to any area on the window that does not obstruct pixels.

[0075] After the getter 4 is fabricated on window 1, window 1 and device wafer 3 are aligned in a bonding machine. The device structure formed after alignment but before bonding is performed is as follows. Figure 7 As shown. After alignment is completed, the bonding steps of window 1 and device wafer 3 are performed according to S022 to S025 above to form a device having a vacuum cavity 5 composed of window 1, solder ring 2 and device wafer 3, specifically as follows. Figure 8 As shown. Then for Figure 8 The device shown performs S04 to activate the getter 4 in the vacuum chamber 5. In this embodiment, the getter 4 is disposed on the side of the window 1 facing the device wafer 3 (corresponding to...). Figure 7 and Figure 8 X-ray lasers cannot provide energy to the surface of getter 4 (the surface facing the device wafer 3) via heat transfer. Therefore, in this embodiment, an infrared laser is used to activate getter 4; that is, the laser in S04 is an infrared laser.

[0076] In some embodiments, the method for fabricating the detector chip provided in this application further includes: after activating the getter 4 in each vacuum chamber 5, performing performance tests on each detector in the detector array, and based on the test results, determining the target detector that needs to be reactivated by the getter 4; then, determining the position of the getter 4 in the target detector according to the position of the target detector; and then using the aforementioned laser through-window 1 to irradiate the area where the getter 4 is located in the vacuum chamber 5 of the target detector to reactivate the getter 4 in the vacuum chamber 5 of the target detector. Existing methods for activating the getter 4 of detectors, if incomplete activation of the getter 4 is found after packaging, may pose a risk of sealing defects if secondary activation is performed using heat, and may easily cause solder melting, affecting the reliability of the device. In this embodiment, during the wafer-level packaging process, after bonding is completed, the getter 4 is activated by laser. After the getter 4 is activated, the detector's performance is tested. Based on the test results, the getter 4 corresponding to the target detector whose activation level is substandard is directly returned to the laser device for secondary activation using laser. This secondary activation process avoids affecting the sealing solder while simultaneously improving the getter 4's gas-getting performance.

[0077] The above description is merely a specific embodiment of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. A method for fabricating a detector chip, characterized in that, Includes the following steps: After aligning the device wafer (3) with the window (1), it is placed in the bonding machine; The bonding cavity (7) formed between the aligned device wafer (3) and the window (1) is evacuated. After the vacuum level in the bonding cavity (7) meets the set conditions, the bonding cavity (7) is preheated and vented. The preheating temperature is lower than the melting point of the solder ring (2) used to bond the device wafer (3) and the window piece (1). After the duration of the preheating exhaust treatment reaches the first set time, the temperature of the bonding cavity (7) is controlled to rise from the preheating temperature to the bonding temperature to melt the solder ring (2), and the window (1) is connected to the solder of the device wafer (3) through the solder ring (2) used to bond the device wafer (3) and the window (1) by pressurization. After the bonding temperature duration reaches the second set time, cooling and depressurization are performed to form a vacuum cavity (5) composed of the solder ring (2), the window (1), and the device wafer (3); the vacuum cavity (5) corresponds to each detector in the detector array, and each vacuum cavity (5) is provided with a corresponding getter (4). The getter (4) is located in the non-device fabrication area on the side of the device wafer (3) where the detector is fabricated, or the blind cell area of ​​the detector, or the non-optical window area of ​​the window (1); The window (1) is provided with a mark corresponding to each of the vacuum cavities (5). Based on the recognition result of the mark, the position information of the getter (4) in the vacuum cavity (5) corresponding to each of the detectors is determined. Based on the position information of the getter (4) in each of the vacuum cavities (5), the laser is controlled to be aligned with the area of ​​the getter (4) in each of the vacuum cavities (5); A laser is used to irradiate the area of ​​the getter (4) in each of the vacuum cavities (5) through the window (1), and is absorbed by the getter (4) in the vacuum cavity (5) to activate the getter (4) in each of the vacuum cavities (5).

2. The preparation method according to claim 1, characterized in that, The laser is a continuous laser.

3. The preparation method according to claim 1, characterized in that, Also includes: Based on the gas absorption rate and gas absorption volume of the getter (4) in each of the vacuum cavities (5), the output power and irradiation time of the laser irradiated onto the window (1) are set.

4. The preparation method according to claim 1, characterized in that, The laser is an infrared laser or an X-ray laser.

5. The preparation method according to claim 1, characterized in that, The preparation method further includes: Getter (4) is fabricated in the non-optical window region on the side opposite to the device wafer (3) of the window (1); The laser is an infrared laser.

6. The preparation method according to claim 1, characterized in that, Also includes: After activating the getter (4) in each of the vacuum cavities (5), the detector array is tested for performance, and based on the test results, the target detector that needs to be activated again with getter (4) is determined. The laser is used to irradiate the area of ​​the getter (4) in the vacuum cavity (5) of the target detector through the window (1) to reactivate the getter (4) in the vacuum cavity (5) of the target detector.

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