Chip preparation method
By adding microscopic examination steps and canceling some microscopic examination steps during the chip preparation process, the problem of easy contamination in the process of chip preparation is solved, and the chip yield and preparation efficiency are improved.
Patent Information
- Application Number
- CN202411245842.3
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-09-06
- Publication Date
- 2025-05-13
AI Technical Summary
The existing chip preparation process is susceptible to contamination, resulting in a low chip yield.
By adding microscopic examination steps during chip preparation, detecting whether there is contamination or abnormality on the surface of the chip, and canceling some microscopic examination steps to reduce the possibility of contamination during chip flow.
It improves the yield of chip preparation, simplifies the preparation process, improves the preparation efficiency, and reduces the possibility of contamination during the chip flow process.
Smart Images
Figure CN119993851A_ABST
Abstract
Description
Technical Field
[0001] The present application belongs to the technical field of chip preparation, and specifically relates to a chip preparation method. Background Art
[0002] The chip preparation process includes front-end process, back-end process and in-process testing. Each process is crucial. Among them, the back-end process mainly involves multiple steps and details from reverse soldering to back thinning. Each step is closely related and affects each other. In the current back-end process, the chip is easily contaminated, resulting in a low chip yield. Summary of the invention
[0003] The technical problem to be solved by the present application is that the back-end process of existing chip preparation is easily contaminated, resulting in a low chip yield. In order to solve the above technical problem, a chip preparation method is provided.
[0004] The technical solution proposed in this application is: A chip preparation method comprises the steps of: S110, performing degumming and cleaning on the infrared chip, and then performing microscopic inspection on the infrared chip; S120, interconnecting the infrared chip and the readout circuit to form an array chip; S130, filling the gaps of the array chip with glue and curing the gaps, and then performing microscopic inspection; S140, applying glue to the contacts of the array chip; S150, thinning the back of the array chip, and then performing microscopic inspection; S160, etching the back of the array chip; S170, performing a degumming process on the array chip, and then performing a microscopic examination; S180, coating the back of the array chip; S190, inspecting the array chip under a microscope and then packaging it.
[0005] Furthermore, step S110 includes: S111, immersing the infrared chip in a first degumming solution, and heating the first degumming solution in a water bath; S112, taking out the infrared chip and immersing it in a second degumming solution, and then heating the second degumming solution in a water bath; S113, taking out the infrared chip, and then immersing the infrared chip in acetone at room temperature; S114, taking out the infrared chip, and then cleaning the infrared chip with alcohol; S115, taking out the infrared chip, and then purging the infrared chip with nitrogen; S116, performing microscopic inspection on the infrared chip.
[0006] Furthermore, the first degumming solution and the second degumming solution are both N-methylpyrrolidone.
[0007] Further, step S150 includes: S151, applying mineral oil on the back of the array chip; S152, using an adsorption tool to adsorb and fix the array chip; S153, grinding and polishing the back of the array chip; S154, cleaning the back of the array chip and inspecting the array chip under a microscope.
[0008] Further, in step S154: if the glue at the contact point is not damaged, then execute step S160; if the glue at the contact point is damaged, then execute steps S155 to S156 first, and then execute step S160; S155, performing a degumming process on the array chip; S156, applying glue to the contacts of the array chip.
[0009] Furthermore, in step S154, the back of the array chip is first wiped with ethylene glycol and then scrubbed with pure water.
[0010] Further, step S160 includes: S161, using a first etching solution to corrode the back of the array chip; S162, using nitrogen to purge the array chip; S163, using a second etching solution to etch the back of the array chip; S164, washing the array chip with water.
[0011] Further, the first etching solution comprises nitric acid, lactic acid, hydrofluoric acid and water, and the volume ratio of nitric acid:lactic acid:hydrofluoric acid:water is (20-55): (15-45):5: (30-40); Among them, the concentration of nitric acid is 69%~71%, the concentration of lactic acid is 85%~90%; the concentration of hydrofluoric acid is 48.8%~49.2%.
[0012] Further, the second etching solution comprises bromine and hydrobromic acid, and the volume ratio of bromine to hydrobromic acid is 0.5 to 100; Among them, the concentration of hydrobromic acid is 40%.
[0013] Further, step S170 includes: S171, using acetone to scrub the contacts of the array chip; S172, cleaning the contacts of the array chip using alcohol; S173, using nitrogen gas to purge the array chip; S174, performing microscopic inspection on the array chip.
[0014] By adopting the above chip preparation method, adding a microscopic inspection step before or after some steps, the chips in each step can be inspected during the chip preparation process, which can improve the yield of chip preparation. In addition, compared with setting up microscopic inspection before or after each step, this method cancels some microscopic inspection steps, which can reduce the possibility of chip contamination during the circulation process, further improve the chip yield, and also simplify the preparation process and improve the preparation efficiency. BRIEF DESCRIPTION OF THE DRAWINGS
[0015] The accompanying drawings are used to provide further understanding of the present application and constitute a part of the specification. They are used to explain the present application together with the embodiments of the present application and do not constitute a limitation of the present application.
[0016] Figure 1 A schematic diagram of a chip preparation method according to an embodiment of the present application. DETAILED DESCRIPTION
[0017] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.
[0018] In the description of the present application, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise" and the like indicating orientations or positional relationships are based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present application.
[0019] In order to facilitate understanding of the technical solution of the present application, the back-end process of existing chip preparation is explained here: in the existing back-end process, in order to improve the yield of the chip, microscopic inspection will be performed before or after each operation, and microscopic inspection will be performed before and after some operations, that is, to detect whether the surface of the product is contaminated in the corresponding step, or to detect other problems. After adding microscopic inspection, the yield will increase compared to the case without microscopic inspection, but the product needs to be transferred to the inspection station during microscopic inspection, which increases the possibility of product contamination during the transfer process. For example, after the microscopic inspection is completed, the product is contaminated during the process of returning to the processing station, resulting in the chip yield is still low. In addition, after adding the microscopic inspection step, due to the large number of microscopic inspection steps, the process is more cumbersome, affecting the preparation efficiency.
[0020] Based on the above technical problems, the present application provides a chip preparation method, which can improve the yield of the chip. Figure 1 As shown, the chip preparation method includes the steps of: S110, the infrared chip is debonded and cleaned, and then the infrared chip is inspected under a microscope.
[0021] It should be noted that, in this embodiment, the infrared chip is prepared in a conventional manner, and the gaps of the infrared chip are filled with photoresist.
[0022] Step S110 includes: S111, immersing the infrared chip in a first degumming solution, and heating the first degumming solution in a water bath.
[0023] Specifically, the first degumming solution is N-methylpyrrolidone, and the first degumming solution is heated to 80° C. in a water bath, and the immersion time of the infrared chip is 20 minutes.
[0024] S112, take out the infrared chip and immerse it in the second degumming solution, and then heat the second degumming solution in a water bath, wherein the second degumming solution is also N-methylpyrrolidone, and the water bath heating temperature and immersion time are the same as those in step S111.
[0025] S113, taking out the infrared chip, and then immersing the infrared chip in acetone at room temperature to remove the residual degumming liquid on the surface of the infrared chip.
[0026] Specifically, the infrared chip is immersed in acetone for 5 minutes.
[0027] S114, taking out the infrared chip, and then cleaning the infrared chip with alcohol to remove the acetone remaining on the surface of the infrared chip.
[0028] Specifically, the infrared chip is cleaned with alcohol for two or more times, each time the infrared chip is immersed in the alcohol, and each time the immersion time is 1 to 2 minutes.
[0029] It should be noted that in steps S111 and S112, the first degumming solution and the second degumming solution are the same degumming solution, and the first degumming solution and the second degumming solution are to reflect that two degumming solutions are used in the two steps, rather than the same one. Similarly, in step S114, the alcohol is preferably multiple, and one portion of alcohol is used each time. Of course, in other embodiments, it is also possible to soak twice in the same portion of alcohol according to actual conditions.
[0030] S115, taking out the infrared chip, and then using nitrogen to purge the infrared chip to remove alcohol and other residues remaining on the surface of the infrared chip.
[0031] Specifically, the infrared chip is purged with nitrogen for at least 30 seconds until there is no trace of liquid on the surface of the infrared chip. Meanwhile, during the purging process, the infrared chip can be placed on a dust-free cloth or dust-free paper.
[0032] S116, performing a microscopic inspection on the infrared chip to detect whether there is any residual glue or contamination on the surface of the infrared chip.
[0033] Specifically, the infrared chip is inspected using a metallographic microscope. If an abnormality is found, a photo is taken and recorded, and the above steps S111 to S116 are repeated as appropriate; if there is no abnormality, step S120 is executed.
[0034] S120, interconnecting the infrared chip and the readout circuit to form an array chip.
[0035] Specifically, in this embodiment, the infrared chip and the readout circuit are interconnected by reverse soldering. After the interconnection is completed, step S130 is performed. It can be understood that in this embodiment, no microscopic inspection is performed before and after the infrared chip and the readout circuit are interconnected, and contamination will not occur during the circulation of the array chip.
[0036] S130, filling the gaps of the array chip with glue and curing the gaps, and then performing microscopic inspection.
[0037] Specifically, the gaps of the array chip are filled with glue by a glue dispenser, and the glue creeping height is greater than 20 μm; after the filling is completed, the glue is cured in an oven, the curing temperature is 80° C., and the curing time is 15 hours.
[0038] In addition, in this embodiment, a metallographic microscope is used to inspect the array chip. If residual glue is detected at the contacts of the array chip, it can be wiped off with a dust-free cotton swab dipped in acetone, and then step S140 is executed; if no abnormality is detected, step S140 is executed.
[0039] Regarding the above-mentioned method of adding microscopic inspection before and after the operation, steps S120 and S130 are used as examples for explanation: if microscopic inspection is performed before and after the reverse soldering, the microscopic inspection step has been performed in step S116 before the reverse soldering. Adding the microscopic inspection step at this time will affect the chip preparation efficiency; adding microscopic inspection after the reverse soldering may cause the chip to be contaminated during the circulation process, and subsequent filling and curing will be performed. After filling and curing, microscopic inspection will be performed again. At this time, even if contamination is detected, it is usually inconvenient to handle, and the chip will usually be directly scrapped, thereby affecting the chip yield. At the same time, adding microscopic inspection after the reverse soldering will also affect the preparation efficiency.
[0040] S140, applying glue to the contacts of the array chip to protect the contacts in subsequent steps.
[0041] Specifically, the glue coating operation is performed under the observation of a stereo microscope; after the glue coating is completed, the array chip is placed on a hot plate, and the array chip is baked on the hot plate, and the baking temperature is 110°C and the time is 20 minutes. The glue coating can be performed using a dust-free cotton swab. In addition, in this step, the glue is a photoresist. It should be noted that since the glue coating needs to be performed under a stereo microscope, the array chip can also be inspected while the glue coating is being performed. After the baking is completed, step S150 is executed.
[0042] S150, thinning the back of the array chip and then performing microscopic inspection.
[0043] Further, step S150 includes: S151, apply mineral oil on the back of the array chip to prevent the array chip from being scratched during the clamping process, and also to make the array chip more firmly adsorbed.
[0044] S152, using an adsorption tool to adsorb and fix the array chip. It should be noted that before adsorption, the adsorption tool can be cleaned with a dust-free cloth soaked in anhydrous ethanol to remove dust particles on the surface of the tool to prevent the array chip from being contaminated.
[0045] S153, grinding and polishing the array chip to thin the back of the array chip.
[0046] Specifically, grinding and polishing were performed using a diamond lathe.
[0047] S154, cleaning the back of the array chip and inspecting the array chip under a microscope.
[0048] As an example, the back of the array chip is first wiped with ethylene glycol, and then brushed with pure water. After brushing, microscopic examination is performed under a metallographic microscope. Specifically, if the glue at the contact point is not damaged, step S160 is performed; if the glue at the contact point is damaged, steps S155 to S156 are first performed, and then step S160 is performed.
[0049] SS155, debonding the array chip.
[0050] Specifically, the contacts are first scrubbed with acetone, then rinsed with an alcohol spray gun, and finally the array chip is purged with nitrogen until there is no trace of liquid, and then step S156 is performed.
[0051] S156, applying glue to the contacts of the array chip. The gluing operation in this step is the same as that in step S140, and will not be described in detail here.
[0052] S160, etching the back of the array chip.
[0053] Further, step S160 includes: S161, using a first etching solution to etch the back of the array chip.
[0054] Specifically, the first etching solution comprises nitric acid, lactic acid, hydrofluoric acid and water, and the volume ratio of nitric acid: lactic acid: hydrofluoric acid: water is (20-55): (15-45): 5: (30-40). The concentration of nitric acid is 69%-71%, the concentration of lactic acid is 85%-90%; and the concentration of hydrofluoric acid is 48.8%-49.2%. In addition, in this step, the etching time of the first etching solution is 2-3 minutes. Preferably, the volume ratio of nitric acid: lactic acid: hydrofluoric acid: water in the first etching solution is 50:45:5:40, 55:40:5:40, 20:25:5:27.5 or 20:15:5:15.
[0055] S162, using nitrogen gas to purge the array chip until there is no trace of liquid on the surface of the array chip.
[0056] Specifically, the array chip is placed on a dust-free cloth or dust-free paper, and then nitrogen is used to continuously blow the array chip for at least 30 seconds until there is no trace of liquid on the surface of the array chip, and then step S163 is performed.
[0057] S163, using a second etching solution to etch the back of the array chip.
[0058] Specifically, the second etching solution includes bromine and hydrobromic acid, and the volume ratio of bromine to hydrobromic acid is 0.5 to 100. The concentration of hydrobromic acid is 40%. In addition, in this step, the etching time of the second etching solution is 5 to 10 seconds.
[0059] S164, washing the array chip with water to remove the residual corrosive liquid. Specifically, pure water is used for washing, and the washing time is 20 minutes. After the washing is completed, step S170 is performed.
[0060] S170, performing a degumming process on the array chip, and then performing a microscopic inspection.
[0061] Further, step S170 includes: S171, using acetone to scrub the contacts of the array chip.
[0062] Specifically, acetone is used to scrub the contacts of the array chip 4 to 5 times to remove the photoresist, and then step S172 is performed.
[0063] S172, using alcohol to clean the contacts of the array chip.
[0064] Specifically, use an alcohol spray gun to clean the contacts for 1 to 2 minutes to remove residual photoresist, and then execute step S173.
[0065] S173, use nitrogen to purge the array chip. It should be noted that this step is the same as the above-mentioned purging step, that is, placing it on a dust-free cloth or dust-free paper and purging it for at least 30 seconds.
[0066] S174, inspect the array chip under a microscope.
[0067] Specifically, a metallographic microscope is used to detect whether the surface of the array chip is damaged, has residual solution, or has dirty marks, etc. If there is no damage, step S180 is performed; if there is damage and / or dirty marks, a photo can be taken and recorded, and the array chip can be determined as a waste or cleaned again according to the situation. The cleaning steps can refer to the above steps S171 to S173, and the microscopic examination is performed again after cleaning.
[0068] S180, coating the back of the array chip. Specifically, a coating machine is used to coat a layer of ZnS film on the back of the array chip, with a film thickness of 520 nm. After the coating is completed, step S190 is performed.
[0069] S190, the array chip is inspected under a microscope and then packaged.
[0070] Further, step S190 includes: S191, use a stereo microscope to inspect the array chip to check whether the array chip is intact, whether the focal plane is normal, and whether the contacts are damaged. If there is no abnormality, execute step S192; if there is an abnormality, take a photo and record it, and determine whether the array chip is a waste or continue to execute step S192 depending on the situation.
[0071] S192, encapsulating the array chip to form a finished chip. Specifically, encapsulation is performed by a Dewar. After the encapsulation is completed, step S193 is executed.
[0072] S193, test the finished chips and put them into storage after passing the test.
[0073] By adopting the above chip preparation method, adding a microscopic inspection step before or after some steps, the chips in each step can be inspected during the chip preparation process, which can improve the yield of chip preparation. In addition, compared with setting up microscopic inspection before or after each step, this method cancels some microscopic inspection steps, which can reduce the possibility of chip contamination during the circulation process, further improve the chip yield, and also simplify the preparation process and improve the preparation efficiency.
[0074] In order to facilitate understanding of the chip preparation method in the above embodiment, several specific embodiments and comparative examples are provided below for illustration: Example 1 First, immerse the infrared chip in N-methylpyrrolidone, heat the N-methylpyrrolidone water bath to 80°C, and take it out after soaking for 20 minutes; then immerse the infrared chip in another portion of N-methylpyrrolidone, and also heat this portion of N-methylpyrrolidone water bath to 80°C, and take it out after soaking for 20 minutes; then immerse the infrared chip in acetone, soak it for 5 minutes and take it out; after taking it out, soak the infrared chip twice with alcohol, soaking for 2 minutes each time. After soaking, use nitrogen to purge the infrared chip until there is no trace of liquid on the surface; after the purge is completed, use a metallographic microscope to detect the infrared chip.
[0075] After the detection is normal, the infrared chip and the readout circuit are interconnected by reverse soldering to form an array chip. Next, the gaps of the array chip are filled with glue and then cured. After curing, the array chip is inspected by a metallographic microscope. If residual glue is detected at the contacts of the array chip, it can be wiped off with a dust-free cotton swab dipped in acetone, and then the next step is performed. If no abnormality is detected, the next step is performed.
[0076] After the microscopic inspection is completed, the glue coating operation is carried out under the observation of a physical microscope, that is, photoresist is applied to the contacts to protect the contacts in the subsequent steps. After the glue coating is completed, mineral oil is applied to the back of the array chip, and then the array chip is adsorbed and fixed using an adsorption tool; then the back of the array chip is polished using a diamond lathe.
[0077] After polishing, wipe the back with ethylene glycol, and then use pure water to brush. After brushing, perform microscopic inspection under a metallographic microscope to check whether the glue at the contact is damaged. If the glue at the contact is damaged, first use acetone to brush the contact, then use an alcohol spray gun to rinse the contact, and finally use nitrogen to purge the array chip until there is no trace of liquid on the surface, and then apply glue to the contacts of the array chip. After the glue is applied, perform the following corrosion steps; if the glue at the contact is not damaged, perform the following corrosion steps.
[0078] For the etching step, the back of the array chip is firstly corroded with the first etching liquid for 3 minutes, and then the array chip is purged with nitrogen until there is no trace of liquid on the surface; next, the array chip is corroded with the second etching liquid for 10 seconds; finally, the array chip is washed with pure water for 20 minutes.
[0079] After the water washing is completed, the array chip is debonded, that is, first use acetone to brush the contacts of the array chip 5 times, then use an alcohol spray gun to clean the contacts for 2 minutes, and finally use nitrogen to purge the array chip until there is no trace of liquid on the surface. After the purge is completed, the array chip is inspected using a metallographic microscope. If the array chip is damaged and / or the imprint is dirty, the array chip can be determined as a waste or the array chip can be cleaned again. The cleaning process is the same as the above-mentioned debonding process, which will not be repeated here. After cleaning, it is inspected again under a microscope until the test is qualified, and the next coating step is performed; if there is no abnormality, the next coating step is directly performed.
[0080] A coating machine is used to coat a layer of ZnS film on the back of the array chip, and then a stereo microscope is used to examine the array chip; if there is an abnormality, the array chip can be determined as a waste or the subsequent packaging steps can be continued; if there is no abnormality, the packaging step is directly performed.
[0081] The array chip is packaged through the Dewar to form a finished chip. After packaging, the finished chip is tested and put into storage after passing the test.
[0082] In this embodiment, the components of the first etching solution include nitric acid, lactic acid, hydrofluoric acid and water, and the volume ratio of nitric acid: lactic acid: hydrofluoric acid: water is 50:45:5:40, the concentration of nitric acid is 69%~71%, the concentration of lactic acid is 85%~90%; the concentration of hydrofluoric acid is 48.8%~49.2%; the components of the second etching solution include bromine and hydrobromic acid, and the volume ratio of bromine: hydrobromic acid is 0.5:100, and the concentration of hydrobromic acid is 40%.
[0083] Example 2 In this embodiment, the composition of the first etching solution is nitric acid: lactic acid: hydrofluoric acid: water = 20:15:5:30 in volume ratio, and the rest is the same as in Embodiment 1.
[0084] Comparative Example 1 In this comparative example, a microscopic inspection step is added before steps S120, S130, S150 and S160, and the microscopic inspection method is performed using a metallographic microscope. The rest is the same as in Example 1.
[0085] Comparative Example 2 In this comparative example, the microscopic inspection steps in steps S110, S130 and S150 are removed, and the rest are the same as in Example 1.
[0086] Comparative Example 3 In this comparative example, the composition of the first etching solution is nitric acid: lactic acid: hydrofluoric acid: water = 60:50:5:20 in volume ratio, and the rest is the same as in Example 1.
[0087] The yield of the chip in Example 1 is 79%, the yield of the chip in Comparative Example 1 is 75%, and the yield of the chip in Comparative Example 2 is 70%. It can be seen that if the microscopic inspection step is added in Comparative Example 1, the probability of chip contamination will increase during the circulation process, resulting in a decrease in yield. If the microscopic inspection step is reduced in Comparative Example 2, problems with the chip cannot be discovered in time, resulting in a decrease in yield.
[0088] The yield of the chip in Example 2 is 76%, and the yield of Comparative Example 3 is 74%. The use of the first etching solution in the chip preparation method provided in the present application, combined with the subsequent steps, can effectively remove the back of the array chip to avoid residue, thereby improving the yield of the chip.
[0089] In summary, it can be determined that the chip preparation method of the present application can improve the yield of chip preparation.
[0090] Although the embodiments of the present application have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present application, and that the scope of the present application is defined by the appended claims and their equivalents.
Claims
1. A chip preparation method, characterized in that: Includes steps: S110, performing degumming and cleaning on the infrared chip, and then performing microscopic inspection on the infrared chip; S120, interconnecting the infrared chip and the readout circuit to form an array chip; S130, filling the gaps of the array chip with glue and curing the gaps, and then performing microscopic inspection; S140, applying glue to the contacts of the array chip; S150, thinning the back of the array chip, and then performing microscopic inspection; S160, etching the back of the array chip; S170, performing a degumming process on the array chip, and then performing a microscopic examination; S180, coating the back of the array chip; S190, inspecting the array chip under a microscope and then packaging it.
2. The chip preparation method according to claim 1, characterized in that: Step S110 includes: S111, immersing the infrared chip in a first degumming solution, and heating the first degumming solution in a water bath; S112, taking out the infrared chip and immersing it in a second degumming solution, and then heating the second degumming solution in a water bath; S113, taking out the infrared chip, and then immersing the infrared chip in acetone at room temperature; S114, taking out the infrared chip, and then cleaning the infrared chip with alcohol; S115, taking out the infrared chip, and then purging the infrared chip with nitrogen; S116, performing microscopic inspection on the infrared chip.
3. The chip preparation method according to claim 2, characterized in that: The first degumming solution and the second degumming solution are both N-methylpyrrolidone.
4. The chip preparation method according to claim 1, characterized in that: Step S150 includes: S151, applying mineral oil on the back of the array chip; S152, using an adsorption tool to adsorb and fix the array chip; S153, grinding and polishing the back of the array chip; S154, cleaning the back of the array chip and inspecting the array chip under a microscope.
5. The chip preparation method according to claim 4, characterized in that: In step S154: if the glue at the contact point is not damaged, then execute step S160; if the glue at the contact point is damaged, then execute steps S155 to S156 first, and then execute step S160; S155, performing a degumming process on the array chip; S156, applying glue to the contacts of the array chip.
6. The chip preparation method according to claim 4, characterized in that: In step S154, the back of the array chip is first wiped with ethylene glycol and then scrubbed with pure water.
7. The chip preparation method according to claim 1, characterized in that: Step S160 includes: S161, using a first etching solution to corrode the back of the array chip; S163, using a second etching solution to etch the back of the array chip; The first etching solution comprises nitric acid, lactic acid, hydrofluoric acid and water, and the volume ratio of nitric acid:lactic acid:hydrofluoric acid:water is (20-55): (15-45):5: (30-40); Among them, the concentration of nitric acid is 69%~71%, the concentration of lactic acid is 85%~90%; the concentration of hydrofluoric acid is 48.8%~49.2%.
8. The chip preparation method according to claim 7, characterized in that: The steps between step S161 and step S163 include: S162, using nitrogen to purge the array chip; Step S163 also includes the following steps: S164, washing the array chip with water.
9. The chip preparation method according to claim 7, characterized in that: The second etching solution comprises bromine and hydrobromic acid, and the volume ratio of bromine to hydrobromic acid is 0.5 to 100; Among them, the concentration of hydrobromic acid is 40%.
10. The chip preparation method according to claim 1, characterized in that: Step S170 includes: S171, using acetone to scrub the contacts of the array chip; S172, cleaning the contacts of the array chip using alcohol; S173, using nitrogen to purge the array chip; S174, performing microscopic inspection on the array chip.