CN115285932A - Preparation method of detector chip - Google Patents

Abstract

The application provides a preparation method of a detector chip, a window sheet and a device wafer are bonded to form a vacuum cavity corresponding to each detection unit in a detector array, laser penetrates through the window sheet to irradiate a getter in the vacuum cavity, and the energy provided by the laser for the getter is used for activating the getter, so that the getter can have the air suction capacity again. In the process of activating the getter, because the laser only aims at the area where the getter is located to irradiate, the energy generated by the laser cannot damage the structure of the detection unit, and meanwhile, the phenomenon that the solder overflows in the activation process can be effectively avoided, and the reliability of the detector chip is improved.

Description

Preparation method of detector chip

technical field

The present application relates to the field of semiconductor technology, in particular to a method for preparing a detector chip.

Background technique

Micro-Electro-Mechanical System (MEMS, Micro-Electro-Mechanical System) technology, as a new microfabrication technology, has begun to be applied in various fields. It can integrate functions such as information acquisition, processing, and execution, and has the advantages of being small, intelligent, executable, integrable, good process compatibility, and low cost. Therefore, MEMS technology also has a very broad application prospect in the field of infrared detection technology, which will provide a new way for research in this field. The use of MEMS technology in the development of uncooled infrared detectors can make devices develop in the direction of high reliability, miniaturization, intelligence, high-density array integration, low cost, and mass production, and it is possible to use this technology to manufacture devices with An uncooled infrared detector with a new mechanism.

The wafer-level packaging of MEMS infrared detectors is based on the wafer as the processing object. Many detector units are packaged on the wafer at the same time to form a detector chip, which is further aged and tested on the wafer before being divided into individual detectors. Chip packaging. Compared with traditional packaging forms, wafer-level packaging has the advantages of high efficiency, short cycle time and low cost. The vacuum degree inside the vacuum chamber of the infrared detector formed during the wafer-level packaging process will have a greater impact on its performance. Therefore, to ensure the excellent performance of the detector, it is necessary to strictly control the vacuum degree inside the detector. Due to the outgassing phenomenon of the internal materials of the detector, the internal vacuum degree will drop during long-term use. Therefore, in order to ensure that the performance of the detector is not affected, it is necessary to set a getter inside the vacuum chamber to maintain its vacuum degree.

In the wafer-level packaging process of the infrared detector, since the surface of the getter exposed to the atmosphere adsorbs gases such as H ₂ O, CO ₂ and hydrocarbons, in order to ensure the vacuum inside the detector vacuum chamber, it is necessary to The getter in the cavity is activated, thereby restoring its getter properties.

At present, the getter of the detector is mainly activated by high-temperature heating, high-frequency induced current activation or thermal radiation activation. Among them, when the getter is activated by high-temperature heating, the high temperature will easily cause thermal failure to the MEMS structure (the pixel area of the detector), and the high temperature will easily cause problems such as package failure and vacuum degree reduction. In addition, the solder is affected by Under the influence of high temperature, it is easy to produce a spill ball, which will have a certain impact on the detector. The use of high-frequency induced current to activate the getter can easily cause the loss of microcircuits, resulting in electrical failure or magnetic failure of the MEMS structure. Obviously, the current getter activation method is easily affected by the material properties and process window, and there is a problem of insufficient getter activation, resulting in insufficient vacuum in the detector's vacuum cavity, which leads to detector failure. In addition, the activation efficiency of heating is low, it is difficult to control precisely, and it is easy to damage the detector.

Contents of the invention

In order to solve the existing technical problems, the present application provides a method for preparing a detector chip that can avoid circuit and device damage during the activation process of the getter.

A method for preparing a detector chip, comprising:

The device wafer fabricated with the detector array is bonded to the corresponding window, and vacuum chambers corresponding to the detectors in the detector array are formed between the device wafer and the window body, each of the vacuum chambers is provided with a corresponding getter;

Laser light is used to irradiate the region of the getter in each of the vacuum chambers through the window, and is absorbed by the getter in the vacuum chamber, so as to activate the region of the getter in each of the vacuum chambers. of the getters.

In some embodiments, the laser is a continuous laser.

In some embodiments, the preparation method also includes:

The corresponding output power and irradiation time of the laser light irradiated on the window plate are set according to the getter rate and the getter volume in each of the vacuum chambers.

In some embodiments, the window is provided with marks corresponding to each of the vacuum chambers, and the preparation method further includes:

determining the position information of the getter in the vacuum cavity corresponding to each of the detectors according to the recognition result of the mark;

According to the position information of the getter in each of the vacuum cavities, the laser is controlled to be aimed at the area of the getter in each of the vacuum cavities.

In some embodiments, the bonding connection of the device wafer with the detector and the corresponding window includes:

After aligning the device wafer with the window, place it in a bonding machine;

vacuumizing the cavity to be bonded formed between the aligned device wafer and the window;

After the vacuum degree in the chamber to be bonded meets the set conditions, the chamber to be bonded is preheated and exhausted, and the preheating temperature is lower than that used for bonding and connecting the device wafer and the window The melting point of the solder ring;

After the duration of the preheating exhaust treatment reaches the first set time, control the temperature of the chamber to be bonded from the preheating temperature to the bonding temperature to melt the The solder ring for bonding and connecting the wafer and the window, and pressurizing the window to pass through the solder ring for bonding the device wafer and the window to the device wafer solder connection;

After the duration of the bonding temperature reaches a second set time, cooling and depressurization are performed to form the vacuum chamber composed of the solder ring, the window and the device wafer.

In some embodiments, before the device wafer fabricated with the detector is bonded to the corresponding window, the preparation method further includes:

A getter is fabricated on the non-device fabrication area on the side of the device wafer where the detector is fabricated or on the blind cell area of the detector.

In some embodiments, the distance between the detection unit of each detector and the corresponding getter is determined according to the corresponding output power of the laser and the irradiation time on the getter.

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

In some embodiments, before the device wafer fabricated with the detector is bonded to the corresponding window, the preparation method further includes:

making a getter in the non-optical window area on the opposite side of the window sheet to the device wafer;

The laser is an infrared laser.

In some embodiments, the preparation method also includes:

After activating the getters in each of the vacuum chambers, performing a performance test on the detector array, and based on the test results, determining the target detectors that need to be activated again with getters;

Use the laser to irradiate the region of the getter in the vacuum cavity of the target detector through the window, so as to irradiate the getter in the vacuum cavity of the target detector The aerosol is reactivated.

It can be seen from the above that in the preparation method of the detector chip provided by the present application, after the window plate is bonded to the device wafer to form a vacuum chamber corresponding to each detection unit in the detector array, and then the laser is used to transmit The getter is irradiated through the window to the getter in the vacuum cavity, and the energy provided by the laser to the getter is used to activate the getter, so that the getter can regain its ability to getter. In the process of activating the getter, since the laser is only irradiated on the area where the getter is located, the energy generated by the laser will not cause damage to the structure of the detection unit, and it can also effectively avoid the generation of solder during the activation process The overflow ball phenomenon is beneficial to improve the reliability performance of the detector chip.

Description of drawings

The drawings are only for illustrating the embodiments and are not to be considered as limiting the invention. Also throughout the drawings, the same reference numerals are used to designate the same components. In the attached picture:

Fig. 1 is a schematic flow chart of a method for preparing a detector chip provided according to some embodiments of the present application;

Fig. 2 is a schematic structural diagram of corresponding devices formed when laser activation is performed during the preparation method of the detector chip according to some embodiments of the present application;

Fig. 3 is a top view of corresponding devices formed when laser activation is performed during the preparation method of the detector chip according to some embodiments of the present application;

Fig. 4 is a schematic diagram of the principle of using a laser to activate a getter during the preparation method of a detector chip according to some embodiments of the present application;

Fig. 5 is a schematic flow diagram of the process of bonding the window and the device wafer according to the method for preparing the detector chip provided by some embodiments of the present application;

6 is a schematic diagram of the corresponding device structure after the window and the device wafer are aligned and before bonding during the method for preparing the detector chip according to some embodiments of the present application;

7 is a schematic diagram of the corresponding device structure after the window is aligned with the device wafer and before bonding during the method for preparing the detector chip according to other embodiments of the present application;

FIG. 8 is a schematic structural diagram of a corresponding device formed when laser activation is performed during a method for preparing a detector chip according to other embodiments of the present application.

Description of component symbols: window 1, solder ring 2, device wafer 3, getter 4, vacuum chamber 5, detection unit 6, chamber to be bonded 7

Detailed ways

The technical solution of the present application will be further elaborated below in combination with the accompanying drawings and specific embodiments.

Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the technical field to which this application belongs. The terms used herein in the description of the application are only for the purpose of describing specific embodiments, and are not intended to limit the implementation of the application. As used herein, the term "and/or" includes any and all combinations of one or more of the associated listed items.

In the description of this application, it is to be understood that the terms "center", "upper", "lower", "front", "rear", "left", "right", "vertical", "row", The orientations or positional relationships indicated by "top", "bottom", "inner", "outer", etc. are based on the orientations or positional relationships shown in the drawings, and are only for the convenience of describing the application and simplifying the description, rather than indicating or implying References to devices or elements must have a particular orientation, be constructed, and operate in a particular orientation and therefore should not be construed as limiting the application. In the description of the present application, unless otherwise specified, "plurality" means two or more.

In the description of this application, it should be noted that unless otherwise specified and limited, the terms "installation", "connection", and "connection" should be understood in a broad sense, for example, it can be a fixed connection or a detachable connection. Connected, or integrally connected; it can be directly connected, or indirectly connected through an intermediary, and it can be the internal communication of two elements. Those of ordinary skill in the art can understand the specific meanings of the above terms in this application according to specific situations.

In order to overcome the adverse effect of the existing getter activation method on the performance of the detector, the present application provides a method for preparing a detector chip using a laser activation method to activate the getter. During the preparation of the detector chip, after the vacuum cavity is formed, laser activation is performed on the position of the getter to avoid structural damage to the detector, and at the same time, it can effectively prevent excessive melting of solder at high temperature to produce overflow balls. The detector chip in the embodiment of the present application may be an uncooled infrared detector chip. The method for preparing the detector chip provided by each embodiment of the present application will be further described below with reference to FIGS. 1 to 8 .

Please refer to FIG. 1 , which is a schematic flowchart of a method for preparing a detector chip according to an embodiment of the present application. In the preparation method of the detector chip provided according to this embodiment, the corresponding device structure schematic diagram before bonding the window plate and the device wafer is shown in Fig. A schematic diagram of the device structure is shown in FIG. 2 or FIG. 8 . In this embodiment, the method for preparing the detector chip includes S02 and S04, which are described in detail as follows.

S02: Connect the device wafer with the detector array to the corresponding window by bonding, and form vacuum cavities corresponding to the detectors in the detector array between the device wafer and the window, each Corresponding getters are arranged in the vacuum cavity.

With reference to Fig. 2, 6, 7 and/or shown in Fig. 8, detector array is the array that is made up of a plurality of MEMS structures, and each MEMS structure is a detecting unit 6 that can detect infrared radiation that is formed by MEMS technology (also can called the infrared sensitive pixel unit). The device wafer 3 may be a silicon wafer fabricated with a detector readout circuit, and the readout circuit in the device wafer 3 is connected to the corresponding detection unit 6 fabricated on the device wafer 3 for reading infrared detection signals. The window 1 is an optical window corresponding to the detector array arranged on the device wafer 3 . The window 1 can be a window wafer corresponding to the device wafer 3, and each optical window unit corresponding to each detection unit 6 in the detector array is arranged on the window wafer, and each optical window unit is connected to the corresponding detection unit 6. The unit 6 forms a vacuum chamber 5 . Therefore, the detector array arranged on the device wafer 3 is composed of as many detection units 6 as there are optical window units on the window wafer, and how many optical window units will be formed after the device wafer 3 and the window wafer are bonded. Each of the vacuum chambers 5 is provided with a corresponding getter 4 and a detection unit 6 . The window 1 can also be a plurality of independent windows corresponding to each detection unit 6 in the detector array, that is, the window 1 includes a number of independent windows corresponding to the number of detection units 6 in the detection array. The windows are respectively bonded on corresponding positions of the device wafer 3 to serve as optical windows of corresponding detection units 6 in the detector array on the device wafer 3 .

A getter 4 is arranged in the vacuum chamber 5 , and the getter 4 can be used to absorb gas in the vacuum chamber 5 after being activated. It should be noted here that the vacuum chamber 5 does not just refer to a vacuum in an absolute sense, but a vacuum chamber whose degree of vacuum satisfies a set vacuum condition. The getter 4 can be located in the non-optical window area of the window 1 , or in the non-device fabrication area or the blind cell area of the detector on the device wafer 3 . The non-light window area refers to the area where the window plate 1 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 of the detection unit 6 from irradiating the detection unit 6 . Blind pixels, also known as invalid pixels, are dead pixels and overheated pixels generated during the production process of the detector array. A dead pixel refers to a pixel whose response rate is less than 1/10 of the average response rate, and an overheated pixel refers to a pixel whose noise voltage is 10 times greater than the average noise voltage.

In some embodiments, a solder ring 2 may be provided on the window 1, and after the window 1 and the device wafer 3 are bonded through the solder ring 2, the window 1, the solder ring 2 and the device wafer 3 form a vacuum chamber 5. A top view of the device structure shown in FIG. 2 is shown in FIG. 3 . It should be noted that FIG. 2 only illustrates the structure corresponding to one detector of the device wafer 3 , and FIG. 3 does not illustrate the detection unit 6 . In Fig. 2, the getter 4 is made on the non-device fabrication area on the side where the detector array is made on the device wafer 3, that is, the getter 4 is located around the detection unit 6 (MEMS structure) and between the detection unit 6. have a certain distance between them. A solder ring 2 is arranged on the window 1 , and the solder ring 2 is arranged on the edge of the area of the window 1 opposite to the getter 4 and the detection unit 6 . After the window 1 passes through the solder ring 2 and the device wafer 3 is bonded, a vacuum cavity 5 is formed.

S04: Using laser light to irradiate the region of the getter in each vacuum cavity through the window, and being absorbed by the getter in the vacuum cavity, so as to activate the getter in each vacuum cavity.

As shown in FIGS. 2 and 3 , in some embodiments, the laser is irradiated from the region of the window 1 corresponding to the getter 4 into the vacuum cavity 5 and reaches the getter 4 to be absorbed by the getter. 4 absorption. After the laser light reaches the getter 4, the getter 4 continuously obtains energy, and the passivation film on the surface of the getter 4 is gradually removed, so that the getter 4 becomes active again, thereby completing the activation of the getter 4. After the getter 4 is activated, it can regain the getter ability. In the preparation process of the detector chip provided in the embodiment of the present application, after the window plate 1 and the device wafer 3 are bonded to form the vacuum cavity 5, the schematic diagram of the principle of using laser to activate the getter 4 in the vacuum cavity 5 is as follows Figure 4 shows. The laser in S04 refers to the laser light that can pass through the window 1 and can be absorbed by the getter 4 when it reaches the getter 4 after passing through the window 1 . After the getter 4 absorbs the laser, the getter 4 obtains energy, so that H ₂ O (water molecules), CO ₂ (carbon dioxide molecules) and hydrocarbons in the getter 4 are gradually desorbed from the surface of the getter 4 , the oxygen element in the metal oxide constituting the getter 4 mainly leaves the surface of the getter 4 in the way of inward diffusion, and the surface of the getter 4 changes from an oxidized state to a near-metal state or a metal state, thereby Make the surface of the getter 4 have the getter ability again.

It can be seen from the above that in the method for preparing the detector chip provided in the embodiment of the present application, the vacuum cavity 5 corresponding to each detection unit 6 in the detector array is formed by bonding the window 1 and the device wafer 3 Finally, the laser light is used to irradiate the getter 4 in the vacuum cavity 5 through the window plate 1, and the energy provided by the laser to the getter 4 is used to activate the getter, so that the getter 4 can regain its ability to getter . In the process of activating the getter 4, since the laser is irradiated only at the area where the getter 4 is located, the energy generated by the laser will not cause damage to the structure of the detection unit 6, and at the same time, the solder overflow can be effectively avoided. The ball phenomenon is beneficial to improve the reliability of the detector chip.

In some embodiments, the window 1 is a semiconductor window coated with an infrared anti-reflection film. The semiconductor window is, for example, a germanium window made of germanium, or a silicon window made of silicon. The semiconductor window coated with the infrared anti-reflection film can pass through the light to be detected of the detector chip. In S04, in order to improve the activation efficiency of the getter 4, it is necessary to make the output power corresponding to the laser in S04 satisfy the set output power condition. Generally, the output power of the laser that generates the laser in S04 needs to reach the set output power, such as 200-500W. In order to avoid damage to the getter 4 when a laser with a higher output power is irradiated on the getter 4, in S04, a continuous laser output mode is further used to irradiate the getter 4 to achieve The agent 4 is activated without causing damage to the getter 4.

In some embodiments, the method for preparing the detector chip further includes: according to the gettering rate and the gettering amount of the getter 4 in each vacuum cavity 5 formed in S02, setting the laser beam irradiated on the window plate 1 to correspond to output power and irradiation time. The inhalation rate of the getter 4 is determined by the constituent material of the getter 4 , and the inhalation capacity of the getter 4 is the total amount of gas that the getter 4 can absorb. After the material of the getter 4 is determined, the larger the total amount of air intake required, the more energy required to activate the getter 4, and the output power and irradiation time required to irradiate the getter 4 Satisfy the getter 4 demand for activation energy.

In the method for fabricating the detector chip according to the embodiment of the present application, it is necessary to activate the getter 4 by aiming at the region where the getter 4 is located by using a laser. Therefore, the method for preparing the detector chip according to the embodiment of the present application further includes a step of aligning the laser light with the getter 4 . In some embodiments, in order to facilitate precise alignment of the window 1 and the device wafer 3, the window 1 is provided with marks corresponding to each detection unit 6 in the detector array arranged on the device wafer 3 ( 2, 6, 7 and 8 are not drawn), that is, according to the obtained position of each mark, the range of each detector on each device wafer 3 can be determined. It should be noted here that each detection unit 6 in the detector array on the device wafer 3 , the corresponding vacuum cavity 5 and the corresponding getter 4 constitute a detector. Therefore, a plurality of detectors are actually arranged on the device wafer 3 , and the position area where each detector is located has a corresponding mark on the window 1 . Therefore, in some embodiments, the specific step of aligning the laser in S04 with the getter 4 may be: according to the recognition results of the marks on the window 1, determine the corresponding detectors in the vacuum chamber 5 According to the position information of the getter 4 in each vacuum chamber 5, the laser is controlled to align with the region of the getter 4 in each vacuum chamber 5 according to the position information of the getter 4 in each vacuum chamber 5. Specifically, the laser device used to generate the laser light in S04 has an identification system, which can identify the marks on the window 1 to determine the position area of each detector, because the getter 4 and the detection unit 6 are in the The positions of the corresponding detectors are definite, so according to the recognition results obtained by identifying the marks, the position information of each detector can be determined, and then according to the position information of the corresponding detectors, the corresponding position in the vacuum chamber 5 can be determined. The position information of the getter 4. After the laser device recognizes the mark on the window plate 1, the position information of the getter 4 can be obtained, and then according to the position information of the getter 4, the laser probe of the laser device is controlled to the horizontal direction (x-axis direction) and /or move in the vertical direction (y-axis direction) to the position of the getter 4 that needs to be activated, and then emit a laser that can pass through the window 1 and aim at the area where the getter 4 is located and be absorbed by the getter 4 . And further according to the performance of the getter 4 (comprising the suction rate and the suction volume of the getter 4), determine the output power of the laser irradiated to the area where the getter 4 is located and the duration of laser irradiation on the getter 4 .

Please refer to FIG. 5 , which is a schematic diagram of a process of bonding a device wafer 3 and a window 1 according to an embodiment of the present application. In this embodiment, S02 further includes S021, S022, S023, S024 and S025.

S021: After aligning the device wafer and the window, place it in the bonding machine.

In this embodiment, the window 1 can be a window wafer, and the window wafer is provided with marks corresponding to the detectors made on the device wafer 3. Based on the positions of the corresponding marks, each of the window wafers can be The window area is aligned with the corresponding detector area in the device wafer 3 . In this embodiment, the edge of the window region corresponding to the window wafer and the device wafer 3 is provided with a solder ring 2 , that is, the solder ring 2 is prefabricated on the window sheet 1 before S021 is performed. In other embodiments, the solder ring 2 may also be prefabricated at the corresponding position of the device wafer 3 before performing S021. The shape of the solder ring 2 is not limited in this application, any shape of the solder ring that can form a closed vacuum chamber 5 with the window 1 and the device wafer 3 after subsequent bonding is acceptable.

S022: Vacuumize the cavity to be bonded formed between the aligned device wafer and the window.

Since the amount of getter 4 is limited, in order to ensure that the vacuum degree of the vacuum chamber 5 of the detector can meet the requirements of device performance, it is necessary to align the device wafer 3 and the window 1 after S021 The cavity 7 to be bonded between them is vacuumized. After the device wafer 3 is aligned with the window 1 but before the bonding is completed, the structural diagrams of the device structures formed according to the method for preparing the detection chip provided by the embodiment of the present application are shown in FIG. 6 and FIG. 7 respectively. The difference between FIG. 6 and FIG. 7 is that the position of the getter 4 is different. In FIG. 6 the getter 4 is arranged on the wafer device 3 , and in FIG. 7 the getter 4 is arranged on the window 1 . After the window 1 and the device wafer 3 are aligned, a chamber 7 to be bonded is formed between the two, and the chamber 7 to be bonded forms the aforementioned vacuum chamber 5 after subsequent bonding steps are completed.

S023: After the vacuum degree in the chamber to be bonded meets the set conditions, preheat and exhaust the chamber to be bonded. The preheating temperature is lower than the melting point of the solder ring used to bond the device wafer and the window. .

The vacuuming of the chamber 7 to be bonded needs to be determined according to the maximum absorption capacity of the getter 4, that is, after the vacuuming step of S022, the degree of vacuum in the chamber 7 to be bonded meets the set conditions. The setting condition may refer to a certain vacuum degree or a certain range of vacuum degree, and its specific value may be set according to the maximum suction capacity of the getter 4 . In some embodiments, the preheating and exhausting treatment of S023 can be performed after the vacuum treatment in S022 controls the vacuum degree in the chamber 7 to be bonded to 10 ⁻¹ to 10 ⁻⁶ mbar. Through the preheating exhaust treatment, the remaining gas in the chamber 7 to be bonded is further degassed by preheating and baking. As shown in Figures 6 and 7, during the preheating and exhausting process, the surface material of the device wafer 3 is degassed in a large amount and is gradually discharged out of the chamber 7 to be bonded with the air flow, ensuring that the vacuum chamber 5 of the subsequent detector has a higher of vacuum. Since the heating temperature is set lower than the melting point temperature of the solder ring 2 during the preheating exhaust process, the solder ring 2 is not melted during the preheating exhaust process. In some embodiments, the corresponding preheating temperature in the process of preheating exhaust gas is 150°C to 300°C, and the duration of preheating exhaust gas treatment generally reaches the set time (the first set time), such as the setting The time may be 40 minutes to 100 minutes.

S024: After the duration of the preheating exhaust treatment reaches the first set time, control the temperature of the chamber 7 to be bonded from the preheating temperature to the bonding temperature to melt the solder ring 2 and make the window Chip 1 is solder connected to device wafer 3 via solder ring 2 .

After the duration of the preheating exhaust treatment reaches the first set time (40min to 100min), it is necessary to further increase the heating temperature, that is, to make the ambient temperature of the solder ring 2 rise 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 , and the heating temperature in S023 is higher than the melting point of the solder ring 2 . In some embodiments, the bonding temperature in S024 can generally be set at 200° C. to 400° C. to melt the solder ring 2 . After the temperature is stabilized to the required bonding temperature, the solder ring 2 between the window 1 and the device wafer 3 is further pressurized, so that the window 1 passes through the solder ring 2 and the device wafer 3 in a pressurized manner. Round 3 solder connections.

S025: After the duration of the bonding temperature reaches the second set time, perform cooling and depressurization treatment to form a vacuum chamber composed of a solder ring, a window and a device wafer.

After the bonding temperature reaches the set temperature, the duration of the bonding temperature reaches the second set time, and during the bonding temperature is maintained at the set temperature, it is always maintained between the window plate 1 and the device wafer 3 The pressure value on the solder ring 2 between them is 500N to 5000N. Know that the duration of the bonding temperature reaches the second set time, then cool down the temperature of the environment where the solder ring 2 is located, and withdraw the above-mentioned applied pressure after the temperature of the environment where the solder ring 2 is located is lower than the set cooling temperature. The second set time here can generally be 3 to 20 minutes, and the set cooling temperature is generally lower than 60°C or below 60°C.

After the bonding between the window 1 and the device wafer 3 is completed, the device wafer 3 bonded with the window 1 is taken out of the bonding machine and placed in a laser device for activation of the getter 4 . The laser device is equipped with an optical recognition system. By recognizing the above-mentioned marks on the window plate 1, the range of detectors on each device wafer 3 is divided. The position where the getter 4 is located) performs track translation in the x direction and the y direction, accurately locates the area where the getter 4 is located for continuous irradiation, the laser penetrates the window 1 to reach the getter 4, and the getter 4 continuously absorbs infrared The light is converted into heat energy to increase the temperature, and the heat is quickly transferred to the surface of the getter 4 inside, so that the passivation film on the surface is gradually removed and the activity is rediscovered, and the getter ability is regained.

In some embodiments, before S02, the method for manufacturing the detection chip according to the embodiment of the present application further includes a step of manufacturing a getter. In some embodiments, as shown in FIGS. 2 and 6 , the getter 4 is fabricated on the device wafer 3 . Specifically, the getter 4 is fabricated in the non-device fabrication region on the side of the detection unit 6 where the detector is fabricated on the device wafer 3 . In other embodiments, the getter 4 can also be fabricated on the blind cell area of the detector on the device wafer 3 to serve as a light-shielding material for the detector. The specific steps for making the getter 4 can be as follows: first, apply glue and pattern the photoresist on the device wafer through a photolithography process, and then deposit the getter on the corresponding position by physical vapor deposition , forming getter 4.

In the embodiment where the getter 4 is fabricated on the device wafer 3 (corresponding to FIG. 2 and FIG. 6 ), the laser used in S04 can be an infrared laser or an X-ray laser. Wherein, 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 the getter 4 in the form of electromagnetic energy. In the process of using the infrared laser to activate the getter 4, since the infrared laser is directly facing the area where the getter 4 is located, it will not irradiate the detection unit 6, so the getter 4 will not be activated while the getter 4 is activated. Damage to the detection unit 6. However, the X-ray laser is used to activate the getter 4. Since the X-ray laser transmits energy to the getter 4 in the form of electromagnetic energy, the whole process will not cause the temperature of other regions of the detector to rise at all, which can effectively Avoid damage to the device during the activation process.

In some embodiments, in the process of activating the getter 4 with the infrared laser, in order to avoid damage to the detection unit 6 next to the getter 4 caused by the heat generated by the infrared laser during the heat transfer process, the present application provides The method for preparing the detector chip further includes: determining the distance between the getter 4 of each detector and the corresponding detection unit 6 according to the corresponding output power of the laser and the irradiation time on the getter 4 . This step is performed before making the getter 4, that is, according to the corresponding output power of the laser and the time of irradiation on the getter 4, determine the distance between the detection unit 6 of each detector and the corresponding getter 4 Afterwards, according to the distance, the photoresist patterning process in the preparation of the getter 4 is performed.

In other embodiments, as shown in FIGS. 7 and 8 , the getter 4 can also be fabricated on the window 1 . Specifically, before performing S02 , the method for preparing the detection chip provided by the present application further includes: making a getter 4 on the non-optical window area of the window plate 1 opposite to the device wafer 3 . Here, the non-optical window area has been explained above, and will not be described again here. As shown in Figure 7, before performing S02, the solder plating is first completed on the window plate 1 by a photolithography process to form a solder ring 2, and then, glue and photoresist are applied on the window plate 1 by a photolithography process. The patterning process is to expose the non-optical window area of the window plate 1 through the photoresist, and then deposit the getter 4 on the non-optical window area by physical vapor deposition, thereby completing the getter 4 plating. Wherein, the non-optical window area is any area on the window that does not block the pixel.

After the getter 4 is made on the window 1, the window 1 and the device wafer 3 are aligned in the bonding machine. After the alignment is completed but before the bonding, the device structure formed is shown in the figure 7. After the alignment is completed, perform the bonding step of the window 1 and the device wafer 3 according to the above S022 to S025 to form a device with a vacuum cavity 5 composed of the window 1, the solder ring 2 and the device wafer 3 , specifically as shown in Figure 8. Then execute S04 on the device shown in FIG. 8 to activate the getter 4 in the vacuum cavity 5 . In this embodiment, since the getter 4 is arranged on the side of the window plate 1 facing the device wafer 3 (corresponding to FIGS. 7 and 8 ), the X-ray laser cannot transfer heat to the surface of the getter 4. (the surface on the side facing the device wafer 3 ) is supplied with energy. Therefore, in this embodiment, an infrared laser is used to align the getter 4 for activation, that is, the laser in S04 is an infrared laser.

In some embodiments, the method for preparing a detector chip provided by the present application further includes: after activating the getter 4 in each vacuum chamber 5, performing a performance test on each detector in the detector array, And based on the test results, determine the target detector that needs to be activated again by the getter 4, and then determine the position of the getter 4 in the target detector according to the position of the target detector, and then use the above-mentioned laser through the window 1 is irradiated to the region where the getter 4 is located in the vacuum cavity 5 of the target detector, so as to reactivate the getter 4 in the vacuum cavity 5 of the target detector. In the existing method of activating the getter 4 of the detector, if it is found that the activation of the getter 4 is not complete after packaging, if the secondary activation is performed by heat, there will be a risk of sealing defects, and it is easy to cause solder Melting affects the reliability of the device. However, in the embodiment of the present application, during the wafer-level packaging process, the getter 4 is activated by laser after the bonding is completed, and after the getter 4 is activated, the detector is tested for performance. Based on the test results, The getter 4 corresponding to the target detector whose activation degree does not meet the standard is directly returned to the laser device, and the getter 4 in the target detector is reactivated by laser. In the process of secondary activation, it can not only avoid the impact on the sealing solder, but also complete the improvement of the getter 4 getter performance.

The above is only a specific implementation of the application, but the scope of protection of the application is not limited thereto. Any person familiar with the technical field can easily think of changes or substitutions within the technical scope disclosed in the application. All should be covered within the scope of protection of this application. Therefore, the protection scope of the present application should be determined by the protection scope of the claims.

Claims (10)

1. A preparation method of a detector chip is characterized by comprising the following steps:

bonding and connecting a device wafer (3) with a detector array with a corresponding window sheet (1), forming vacuum cavities (5) between the device wafer (3) and the window sheet (1) and respectively corresponding to detectors in the detector array, wherein each vacuum cavity (5) is provided with a corresponding getter (4);

and irradiating the area of the getter (4) in each vacuum cavity (5) through the window sheet (1) by using laser, and absorbing the getter (4) in each vacuum cavity (5) to activate the getter (4) in each vacuum cavity (5).

2. The method of claim 1, wherein the laser is a continuous laser.

3. The method of claim 1, further comprising:

and setting the output power and the irradiation time corresponding to the laser irradiated on the window sheet (1) according to the suction rate and the suction amount of the getter (4) in each vacuum cavity (5).

4. The production method according to claim 1, wherein the window sheet (1) is provided with marks corresponding to the respective vacuum chambers (5), and the production method further comprises:

according to the identification result of the mark, determining the position information of the getter (4) in the vacuum cavity (5) corresponding to each detector;

and controlling the laser to be aligned with the area of the getter (4) in each vacuum cavity (5) according to the position information of the getter (4) in each vacuum cavity (5).

5. The method for manufacturing according to claim 1, wherein the bonding connection of the device wafer (3) on which the probe is manufactured and the corresponding window piece (1) comprises:

after aligning the device wafer (3) and the window sheet (1), placing the device wafer and the window sheet in a bonding machine;

vacuumizing a cavity (7) to be bonded formed between the aligned device wafer (3) and the window piece (1);

after the vacuum degree in the cavity (7) to be bonded meets a set condition, preheating and exhausting the cavity (7) to be bonded, wherein the preheating temperature is lower than the melting point of a solder ring (2) for bonding and connecting the device wafer (3) and the window piece (1);

after the duration of the preheating exhaust treatment reaches a first set time, controlling the temperature of the cavity to be bonded (7) to rise from the preheating temperature to a bonding temperature so as to melt the solder ring (2), and enabling the window sheet (1) to be in solder connection with the device wafer (3) through the solder ring (2) for bonding connection of the device wafer (3) and the window sheet (1) in a pressurizing mode;

and after the duration time of the bonding temperature reaches a second set time, cooling and pressure-releasing treatment are carried out to form the vacuum cavity (5) consisting of the solder ring (2), the window sheet (1) and the device wafer (3).

6. The method for manufacturing according to claim 1, wherein before the bonding connection of the device wafer (3) on which the probe is fabricated with the corresponding window piece (1), the method further comprises:

and manufacturing the getter (4) on a non-device manufacturing region on one side of the device wafer (3) where the detector is manufactured or a blind pixel region of the detector.

7. The method according to claim 6, wherein the distance between the detection unit (6) of each detector and the corresponding getter (4) is determined according to the output power corresponding to the laser and the time of irradiation on the getter (4).

8. The method of claim 6, wherein the laser is an infrared laser or an X-ray laser.

9. The method for manufacturing according to claim 1, wherein before the bonding connection of the device wafer (3) on which the probe is fabricated with the corresponding window piece (1), the method further comprises:

-making a getter (4) in a non-optical window area of the window sheet (1) on the side opposite to the device wafer (3);

the laser is infrared laser.

10. The method of claim 1, further comprising:

after the getters (4) in the vacuum cavities (5) are activated, performing performance test on the detector array, and determining a target detector which needs to be subjected to getter (4) activation again based on a test result;

and irradiating the laser to the area of the getter (4) in the vacuum cavity (5) of the target detector through the window sheet (1) so as to perform reactivation treatment on the getter (4) in the vacuum cavity (5) of the target detector.

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