Method for removing silicon wafer box seal after alkali washing

Abstract

The invention discloses a method for removing a box seal of a silicon wafer after alkali washing, and relates to the technical field of semiconductors, and the method comprises the following steps: 1, preprocessing the silicon wafer; 2, optimized alkali washing is carried out; and step 3, post-processing and quality verification. According to the method, the alkali cleaning link is optimized, TMAH liquid medicine with the concentration of 2%-5% is adopted in a first alkali cleaning tank, the cleaning temperature of 28-32 DEG C and the ultrasonic power of 45-55 kHz are matched, the cleaning time is prolonged to 120 seconds from traditional 80 seconds, meanwhile, a silicon boat is controlled to rotate at the speed of 5-10 r / min, it is ensured that a silicon wafer makes contact with the liquid medicine in all directions, blue liquid medicine residues fully react and are peeled off, and the quality of the silicon wafer is improved. And subsequently washing the deionized water in the second tank by alkali and rinsing for 50-70 seconds by 40-50kHz ultrasonic waves to further remove the reaction product, so that the stripping rate of the blue liquid medicine residue is 100%, the subsequent process pollution caused by the residue is avoided, a clean silicon wafer substrate is provided for manufacturing a semiconductor device, and the production quality of the silicon wafer is improved.

Description

Technical Field

[0001] This invention relates to the field of semiconductor technology, and more specifically to a method for removing wafer cassette marks after alkaline washing. Background Technology

[0002] In the semiconductor manufacturing field, silicon wafers are the core substrate material, and their surface cleanliness directly determines the precision of subsequent photolithography, deposition and other processes and the performance of devices. In the silicon wafer processing, alkaline washing (commonly tetramethylammonium hydroxide, TMAH) is a key process to remove the surface damage layer and achieve precise thinning. However, alkaline washing is prone to two major problems: wafer cassette printing residue and blue chemical residue. In order to improve production quality, the residue needs to be removed.

[0003] Existing removal methods have significant drawbacks:

[0004] The traditional method of cleaning with deionized water alone cannot completely remove the initial dust and oil on the silicon wafer surface. During subsequent acid etching, impurities are easily formed and masked, resulting in uneven thinning. The traditional cleaning time is only 80 seconds, and the reaction between TMAH and blue residue is insufficient. In addition, the silicon boat is stationary or rotates at low speed, and the solution cannot fully contact the edge of the silicon wafer. The wafer cassette peeling rate is less than 80%, which is inefficient. At the same time, silicon wafers of different specifications may get stuck and unable to rotate during processing, resulting in edge stains and wafer cassette marks. This method has great limitations. Summary of the Invention

[0005] This invention provides a method for removing wafer cassette marks after alkaline washing, in order to solve the problems mentioned in the background art.

[0006] To solve the above-mentioned technical problems, the technical solution adopted by the present invention is as follows:

[0007] A method for removing wafer cassette marks after alkaline washing, comprising the following steps:

[0008] Step 1: Silicon wafer pretreatment;

[0009] Step 2: Optimize alkaline washing;

[0010] Step 3: Post-processing and quality verification.

[0011] A further improvement to the technical solution of the present invention is that step one further includes the following steps:

[0012] A1: A conventional enclosed side-bar type wafer cassette is used to hold the silicon wafers to be processed. Deionized water is used as the cleaning solution, and ultrasonic treatment is combined to remove the initial dust and oil on the surface of the silicon wafers. The cleaned silicon wafers are then transferred to an acid etching tank, where a mixed acid solution is used for etching to achieve precise thinning of the silicon wafers. The acid-etched silicon wafers are then placed in a mixed cleaning solution containing hydrofluoric acid (HF) and tetramethylammonium hydroxide (TMAH), and ultrasonic treatment is combined to initially remove the silicon oxides and metal ions remaining after acid etching.

[0013] A2: Place the cleaned silicon wafers in a clean environment and use optical inspection to screen out qualified silicon wafers that are free of scratches and pitting defects.

[0014] A further improvement to the technical solution of the present invention is that step two further includes the following steps:

[0015] B1: Transfer the qualified silicon wafers from the conventional closed side-panel wafer cassette to the silicon wafer cleaning device. Place the silicon wafer cleaning device containing the silicon wafers into an alkaline cleaning tank filled with TMAH solution. Control the cleaning temperature, ultrasonic power, and cleaning time to ensure that the residual blue solution on the surface of the silicon wafers reacts fully and is peeled off. The cleaning time is set to 120 seconds, which is 40 seconds longer than the traditional 80-second cleaning time.

[0016] B2: Transfer the cleaned silicon wafers to the second alkaline cleaning tank, and use deionized water in conjunction with ultrasonic treatment to remove the TMAH reaction products adhering to the surface of the silicon wafers.

[0017] A further improvement to the technical solution of the present invention is that step three further includes the following steps:

[0018] C1: Place the rinsed silicon wafers into a spin dryer to remove moisture from the surface of the silicon wafers through centrifugal action. Place the spin-dried silicon wafers in a Class 1000 cleanroom and visually inspect them under fluorescent and spotlights to confirm that there is no blue chemical residue or wafer box mark on the surface and edges of the silicon wafers.

[0019] C2: For silicon wafers that have passed the visual inspection, further visual inspection is conducted to confirm whether there are any wafer cassette stains on the edges, thus completing the quality verification.

[0020] A further improvement to the technical solution of this invention is as follows: In step one, the ultrasonic treatment power is 40-60kHz, and the treatment time is 50-70 seconds; the resistivity of the deionized water is ≥18.2MΩ·cm; the volume ratio of the mixed acid solution is HF:HNO3:CH3COOH=1:3:2; the corrosion temperature is controlled at 25-30℃; the corrosion time is 110-130 seconds; and the silicon wafer thinning is controlled at 3-5μm. The concentration parameters of the mixed cleaning solution are: HF concentration 5%~8%, TMAH concentration 2%~5%; the ultrasonic treatment power is 45-65kHz; the treatment time is 80-100 seconds; the cleaning temperature is maintained at 25-35℃; the optical inspection uses an optical microscope with a magnification of 150-250x; and the clean environment is a Class 1000 cleanroom with an ambient temperature of 23±2℃ and a relative humidity of 45±5%.

[0021] A further improvement to the technical solution of this invention is as follows: the concentration of the TMAH solution in step two is 2% to 5%, the cleaning temperature is controlled at 28-32℃, and the ultrasonic power is 45-55kHz; during the cleaning process, the rotation speed of the silicon boat is 5-10r / min to ensure that the silicon wafer is in full contact with the TMAH solution; the ultrasonic power in step 2.3 is 40-50kHz, and the rinsing time is 50-70 seconds; the resistivity of the deionized water used for rinsing is ≥18.2MΩ·cm, and the water temperature is maintained at 25-30℃.

[0022] A further improvement to the technical solution of this invention is as follows: the centrifugal speed of the spin dryer in step three is 1600-2000 rpm, and the spin drying time is 3-5 minutes; during the spin drying process, the silicon wafers are placed horizontally to avoid water stains remaining on the surface of the silicon wafers; the power of the fluorescent lamp is 30-40W, and the vertical distance between the fluorescent lamp and the surface of the silicon wafer is 35-45cm; the power of the spotlight is 45-55W, the illuminance is 900-1100 lux, and the vertical distance between the spotlight and the surface of the silicon wafer is 30-40cm; during visual inspection, the observation angle is 40-50° with the surface of the silicon wafer, and the single observation time is not less than 10 seconds; the judgment criteria for the inspection of the silicon wafer surface are: no visible blue liquid residue on the surface of the silicon wafer, and no wafer cassette stains with a width ≥0.1mm on the edge; if unqualified silicon wafers are found, the process of steps two and three must be repeated, and the number of reprocessing times shall not exceed one, to avoid excessive corrosion of the silicon wafers.

[0023] A further improvement of the technical solution of the present invention is that it includes a box body one and a box body two, with a guide rod one and two guide rods two slidably arranged between the box body one and the box body two, and an adjustment component is provided. The adjustment component includes a bidirectional lead screw, which is threadedly engaged with the box body one and the box body two. The inner walls of the box body one and the box body two are provided with a plurality of silicon wafer slots. When the bidirectional lead screw rotates forward, it drives the box body one and the box body two to move towards each other. A fixing frame two and two reinforcing plates two are sleeved on the bidirectional lead screw and the guide rods two. The fixing frame one and the two reinforcing plates one are fixedly sleeved on the two guide rods one. A lifting block is fixedly installed on one side of the fixing frame one and the fixing frame two.

[0024] A further improvement of the technical solution of the present invention is that: the second fixing frame and the second reinforcing plate are both fixedly connected to the second guide rod and rotate in cooperation with the bidirectional lead screw; the first fixing frame and the first reinforcing plate are both fixedly connected to the two first guide rods; the adjustment assembly further includes a rotating shaft and a rotating handle; the rotating shaft is fixedly connected to one end of the bidirectional lead screw; the rotating handle is fixedly connected to the rotating shaft; the fixing frame is fitted in the middle position of the rotating shaft and the second guide rod; and the second fixing frame is fitted in the middle position of the two first guide rods.

[0025] Due to the adoption of the above technical solution, the technical progress achieved by this invention compared to the prior art is as follows:

[0026] 1. This invention provides a method for removing wafer cassette marks from silicon wafers after alkaline washing. By optimizing the alkaline washing process, a 2%–5% concentration of TMAH solution is used in the first alkaline washing tank, combined with a cleaning temperature of 28–32°C and an ultrasonic power of 45–55 kHz. The cleaning time is extended from the traditional 80 seconds to 120 seconds. At the same time, the silicon boat is controlled to rotate at a speed of 5–10 r / min to ensure that the silicon wafer is in full contact with the solution, allowing the blue solution residue to fully react and peel off. Subsequently, the wafer is rinsed in a second alkaline washing tank with deionized water and 40–50 kHz ultrasonic waves for 50–70 seconds to further remove reaction products. Ultimately, a 100% peeling rate of blue solution residue is achieved, avoiding subsequent process contamination caused by residue and providing a clean silicon wafer substrate for semiconductor device manufacturing.

[0027] 2. This invention provides a method for removing wafer cassette marks after alkaline washing. In the pretreatment stage, metal ions are initially removed by using a mixed cleaning solution containing HF and TMAH combined with 45-65kHz ultrasonic treatment. The alkaline washing stage is optimized by extending the reaction time and improving the uniformity of the cleaning solution contact, further removing the blue cleaning solution residue and its carried metal ions, ultimately ensuring that the metal ion content on the silicon wafer surface is ≤1×10⁻⁶. 10 atoms / cm 2It meets the stringent standards for semiconductor-grade silicon wafers, effectively reducing the risk of device leakage and improving the performance stability and reliability of semiconductor devices.

[0028] 3. This invention provides a method for removing wafer cassette marks after alkaline washing. By rotating the handle to drive the bidirectional lead screw, the first and second cassettes move in opposite directions. The gap between the wafer slot and the wafer is adjusted according to the wafer size, avoiding the problem of localized chemical accumulation caused by the fixed gap of traditional closed wafer cassettes. This reduces chemical residue at the contact point between the wafer cassette and the wafer from the source, indirectly achieving a similar effect to open wafer cassettes in reducing contact contamination and lowering the probability of wafer cassette marks. At the same time, the method has a wide adjustment range and can clean wafers of different sizes, making it highly applicable. Attached Figure Description

[0029] Figure 1 This is a schematic diagram of the operation steps of a method for removing silicon wafer cassette marks after alkaline washing according to the present invention;

[0030] Figure 2 This is a three-dimensional structural diagram of a silicon wafer cleaning device according to the present invention;

[0031] Figure 3 for Figure 2 A magnified structural diagram of part A in the middle;

[0032] Figure 4 This is a three-dimensional structural diagram of a silicon wafer cleaning device according to the present invention.

[0033] In the picture:

[0034] 1. Box Body One; 100. Silicon Wafer Groove; 2. Box Body Two; 301. Guide Rod One; 302. Guide Rod Two; 401. Fixing Frame One; 402. Fixing Frame Two; 403. Lifting Block; 5. Adjustment Assembly; 501. Two-Way Lead Screw; 502. Rotary Shaft; 503. Rotary Handle; 601. Reinforcing Plate One; 602. Reinforcing Plate Two; Detailed Implementation

[0035] The present invention will be further described in detail below with reference to embodiments:

[0036] Example 1

[0037] like Figure 1 As shown, the present invention provides a method for removing wafer cassette marks after alkaline washing. The method for removing wafer cassette marks after alkaline washing includes the following steps:

[0038] Step 1: Silicon wafer pretreatment;

[0039] Step 2: Optimize alkaline washing;

[0040] Step 3: Post-processing and quality verification.

[0041] Step one also includes the following steps:

[0042] A1: A conventional enclosed side-bar type wafer cassette is used to hold the silicon wafers to be processed. Deionized water is used as the cleaning solution, and ultrasonic treatment is combined to remove the initial dust and oil on the surface of the silicon wafers. The cleaned silicon wafers are then transferred to an acid etching tank, where a mixed acid solution is used for etching to achieve precise thinning of the silicon wafers. The acid-etched silicon wafers are then placed in a mixed cleaning solution containing hydrofluoric acid (HF) and tetramethylammonium hydroxide (TMAH), and ultrasonic treatment is combined to initially remove the silicon oxides and metal ions remaining after acid etching.

[0043] A2: Place the cleaned silicon wafers in a clean environment and use optical inspection to screen out qualified silicon wafers that are free of scratches and pitting defects.

[0044] Step two also includes the following steps:

[0045] B1: Transfer the qualified silicon wafers from the conventional closed side-panel wafer cassette to the silicon wafer cleaning device. Place the silicon wafer cleaning device containing the silicon wafers into an alkaline cleaning tank filled with TMAH solution. Control the cleaning temperature, ultrasonic power, and cleaning time to ensure that the residual blue solution on the surface of the silicon wafers reacts fully and is peeled off. The cleaning time is set to 120 seconds, which is 40 seconds longer than the traditional 80-second cleaning time.

[0046] B2: Transfer the cleaned silicon wafers to the second alkaline cleaning tank, and use deionized water in conjunction with ultrasonic treatment to remove the TMAH reaction products adhering to the surface of the silicon wafers.

[0047] Step three also includes the following steps:

[0048] C1: Place the rinsed silicon wafers into a spin dryer to remove moisture from the surface of the silicon wafers through centrifugal action. Place the spin-dried silicon wafers in a Class 1000 cleanroom and visually inspect them under fluorescent and spotlights to confirm that there is no blue chemical residue or wafer box mark on the surface and edges of the silicon wafers.

[0049] C2: For silicon wafers that have passed the visual inspection, further visual inspection is conducted to confirm whether there are any wafer cassette stains on the edges, thus completing the quality verification.

[0050] In step one, the ultrasonic treatment power is 40-60kHz, and the treatment time is 50-70 seconds; the resistivity of deionized water is ≥18.2MΩ·cm; the volume ratio of the mixed acid solution is HF:HNO3:CH3COOH=1:3:2; the etching temperature is controlled at 25-30℃, and the etching time is 110-130 seconds; the silicon wafer thinning is controlled at 3-5μm; the concentration parameters of the mixed cleaning solution are: HF concentration 5%~8%, TMAH concentration 2%~5%; the ultrasonic treatment power is 45-65kHz, and the treatment time is 80-100 seconds; the cleaning temperature is maintained at 25-35℃; optical inspection is performed using an optical microscope with a magnification of 150-250x; the clean environment is a Class 1000 cleanroom with an ambient temperature of 23±2℃ and a relative humidity of 45±5%.

[0051] In step two, the concentration of TMAH solution is 2%–5%, the cleaning temperature is controlled at 28–32℃, and the ultrasonic power is 45–55kHz. During the cleaning process, the rotation speed of the silicon boat is 5–10 r / min to ensure that the silicon wafer is in full contact with the TMAH solution. In step 2.3, the ultrasonic power is 40–50kHz, and the rinsing time is 50–70 seconds. The resistivity of the deionized water used for rinsing is ≥18.2 MΩ·cm, and the water temperature is maintained at 25–30℃.

[0052] In step three, the centrifugal speed of the spin dryer is 1600-2000 rpm, and the spin drying time is 3-5 minutes. During the spin drying process, the silicon wafers are placed horizontally to avoid water stains on the surface. The power of the fluorescent lamp is 30-40W, and the vertical distance between the fluorescent lamp and the silicon wafer surface is 35-45cm. The power of the spotlight is 45-55W, the illuminance is 900-1100 lux, and the vertical distance between the spotlight and the silicon wafer surface is 30-40cm. During visual inspection, the observation angle is 40-50° to the silicon wafer surface, and the single observation time is not less than 10 seconds. The judgment criteria for the silicon wafer surface inspection are: no visible blue chemical residue on the silicon wafer surface, and no wafer cassette stains with a width ≥0.1mm on the edge. If unqualified silicon wafers are found, step three must be repeated, and the number of reprocessing times should not exceed one to avoid excessive corrosion of the silicon wafers.

[0053] In this embodiment, efficient removal is achieved through two major optimizations: first, extending the alkaline washing time to 120 seconds ensures sufficient reaction between TMAH and residues; second, controlling the silicon boat rotation speed to 5-10 r / min solves the problem of blind spots in localized contact with the chemical solution, increasing the wafer cassette peeling rate from the traditional 80% to 100%, and completely removing blue residues, meeting the stringent requirements of semiconductor devices for the cleanliness of silicon wafer edges. On the one hand, by precisely controlling the acid etching parameters, the silicon wafer thinning is stabilized at 3-5 μm, avoiding the decrease in silicon wafer strength caused by excessive thinning; on the other hand, the number of reworks for unqualified silicon wafers is limited to ≤1, eliminating the problem of repeated processing and silicon wafer scrapping from the process perspective, reducing the material loss rate from the traditional 5% to 8% to below 0.2%, significantly reducing production costs.

[0054] Example 2

[0055] like Figure 2-4 As shown, in one embodiment, the device includes a housing 1 and a housing 2. A guide rod 301 and two guide rods 302 are slidably disposed between housing 1 and housing 2. An adjustment assembly 5 is also provided, comprising a bidirectional lead screw 501 that is threaded into housing 1 and housing 2. The inner walls of housing 1 and housing 2 are each provided with several silicon wafer slots 100. When the bidirectional lead screw 501 rotates forward, it drives housing 1 and housing 2 to move towards each other. A fixing frame 402 and two reinforcing plates 602 are sleeved on the bidirectional lead screw 501 and guide rods 302. The fixing frame 401 and the two reinforcing plates are fixedly sleeved on the two guide rods 301. A lifting block 403 is fixedly installed on one side of both the first fixed frame 401 and the second fixed frame 402. The second fixed frame 402 and the second reinforcing plate 602 are both fixedly connected to the second guide rod 302 and rotate in cooperation with the double-acting screw 501. The first fixed frame 401 and the first reinforcing plate 601 are both fixedly connected to the two guide rods 301. The adjustment assembly 5 also includes a rotating shaft 502 and a handle 503. The rotating shaft 502 is fixedly connected to one end of the double-acting screw 501, and the handle 503 is fixedly connected to the rotating shaft 502. The first fixed frame 401 is sleeved in the middle position of the rotating shaft 502 and the second guide rod 302, and the second fixed frame 402 is sleeved in the middle position of the two guide rods 301.

[0056] In this embodiment, the operator first places the silicon wafer in the wafer slot 100 within box 1 or box 2, and then rotates the handle 503. The rotation of the handle 503 drives the rotating shaft 502 and the bidirectional lead screw 501 to rotate clockwise. When the bidirectional lead screw 501 rotates, it engages with the threads of box 1 and box 2, causing box 1 and box 2 to move towards each other, thus squeezing the silicon wafer until it is a certain distance from the inside of the two wafer slots 100, at which point the rotation stops. The operator can adjust the relative position of box 1 and box 2 according to the size of the silicon wafer, thus achieving effective cleaning of silicon wafers of different sizes. Simultaneously, adjusting the gap between the silicon wafer and the wafer slot 100 prevents the silicon wafer from getting stuck, making it highly adaptable. Furthermore, by using mechanical equipment to grab the two lifting blocks 403, the equipment can be lifted from both sides. The two lifting blocks 403 are always centered relative to box 1 and box 2, without any deviation affecting the stability of the equipment during lifting, further improving its applicability.

[0057] The present invention has been described in detail above. However, modifications or improvements can be made to it, which will be obvious to those skilled in the art. Therefore, any modifications or improvements that do not depart from the spirit of the present invention are within the scope of protection of the present invention.

Claims

1. A method for removing wafer cassette markings after alkaline washing, characterized in that: The method for removing wafer cassette marks after alkaline washing includes the following steps: Step 1: Silicon wafer pretreatment; Step 2: Optimize alkaline washing; Step 3: Post-processing and quality verification.

2. The method for removing wafer cassette markings after alkaline washing according to claim 1, characterized in that: Step one also includes the following steps: A1: A conventional enclosed side-bar type wafer cassette is used to hold the silicon wafers to be processed. Deionized water is used as the cleaning solution, and ultrasonic treatment is combined to remove the initial dust and oil on the surface of the silicon wafers. The cleaned silicon wafers are then transferred to an acid etching tank, where a mixed acid solution is used for etching to achieve precise thinning of the silicon wafers. The acid-etched silicon wafers are then placed in a mixed cleaning solution containing hydrofluoric acid (HF) and tetramethylammonium hydroxide (TMAH), and ultrasonic treatment is combined to initially remove the silicon oxides and metal ions remaining after acid etching. A2: Place the cleaned silicon wafers in a clean environment and use optical inspection to screen out qualified silicon wafers that are free of scratches and pitting defects.

3. The method for removing wafer cassette markings after alkaline washing according to claim 1, characterized in that: Step two also includes the following steps: B1: Transfer the qualified silicon wafers from the conventional closed side-panel wafer cassette to the silicon wafer cleaning device. Place the silicon wafer cleaning device containing the silicon wafers into an alkaline cleaning tank filled with TMAH solution. Control the cleaning temperature, ultrasonic power, and cleaning time to ensure that the residual blue solution on the surface of the silicon wafers reacts fully and is peeled off. The cleaning time is set to 120 seconds, which is 40 seconds longer than the traditional 80-second cleaning time. B2: Transfer the cleaned silicon wafers to the second alkaline cleaning tank, and use deionized water in conjunction with ultrasonic treatment to remove the TMAH reaction products adhering to the surface of the silicon wafers.

4. The method for removing wafer cassette markings after alkaline washing according to claim 1, characterized in that: Step three also includes the following steps: C1: Place the rinsed silicon wafers into a spin dryer to remove moisture from the surface of the silicon wafers through centrifugal action. Place the spin-dried silicon wafers in a Class 1000 cleanroom and visually inspect them under fluorescent and spotlights to confirm that there is no blue chemical residue or wafer box mark on the surface and edges of the silicon wafers. C2: For silicon wafers that have passed the visual inspection, further visual inspection is conducted to confirm whether there are any wafer cassette stains on the edges, thus completing the quality verification.

5. The method for removing wafer cassette markings after alkaline washing according to claim 2, characterized in that: In step one, the ultrasonic treatment power is 40-60kHz, and the treatment time is 50-70 seconds; the resistivity of the deionized water is ≥18.2MΩ·cm; the volume ratio of the mixed acid solution is HF:HNO3:CH3COOH=1:3:2; the corrosion temperature is controlled at 25-30℃, the corrosion time is 110-130 seconds, the silicon wafer thinning is controlled at 3-5μm; the concentration parameters of the mixed cleaning solution are: HF concentration 5%~8%, TMAH concentration 2%~5%; the ultrasonic treatment power is 45-65kHz, and the treatment time is 80-100 seconds; the cleaning temperature is maintained at 25-35℃; the optical inspection uses an optical microscope with a magnification of 150-250x; the clean environment is a Class 1000 cleanroom with an ambient temperature of 23±2℃ and a relative humidity of 45±5%.

6. The method for removing wafer cassette markings after alkaline washing according to claim 3, characterized in that: In step two, the concentration of the TMAH solution is 2%–5%, the cleaning temperature is controlled at 28–32℃, and the ultrasonic power is 45–55kHz. During the cleaning process, the rotation speed of the silicon boat is 5–10 r / min to ensure that the silicon wafer is in full contact with the TMAH solution. In step 2.3, the ultrasonic treatment power is 40–50kHz, and the rinsing time is 50–70 seconds. The resistivity of the deionized water used for rinsing is ≥18.2 MΩ·cm, and the water temperature is maintained at 25–30℃.

7. The method for removing wafer cassette markings after alkaline washing according to claim 4, characterized in that: In step three, the centrifugal speed of the spin dryer is 1600-2000 rpm, and the spin-drying time is 3-5 minutes. During the spin-drying process, the silicon wafers are placed horizontally to avoid water stains on the wafer surface. The power of the fluorescent lamp is 30-40W, and the vertical distance between the fluorescent lamp and the silicon wafer surface is 35-45cm. The power of the spotlight is 45-55W, the illuminance is 900-1100 lux, and the vertical distance between the spotlight and the silicon wafer surface is 30-40cm. During visual inspection, the observation angle is 40-50° with the silicon wafer surface, and each observation lasts no less than 10 seconds. The criteria for judging the silicon wafer surface inspection are: no visible blue chemical residue on the silicon wafer surface, and no wafer cassette stains with a width ≥0.1mm on the edges. If unqualified silicon wafers are found, the process of steps two and three must be repeated, and the number of reprocessing times should not exceed one to avoid excessive corrosion of the silicon wafers.

8. The silicon wafer cleaning apparatus according to claim 3, characterized in that: The device includes a housing 1 (1) and a housing 2 (2). A guide rod 1 (301) and two guide rods 2 (302) are slidably disposed between the housing 1 (1) and the housing 2 (2). An adjustment assembly (5) is also provided. The adjustment assembly (5) includes a bidirectional lead screw (501), which is threadedly engaged with the housing 1 (1) and the housing 2 (2). The inner walls of both the housing 1 (1) and the housing 2 (2) are provided with several silicon wafer slots (100). When the bidirectional lead screw (501) rotates forward, it drives the first box (1) and the second box (2) to move towards each other. The bidirectional lead screw (501) and the second guide rod (302) are fitted with a second fixing frame (402) and two second reinforcing plates (602). The first guide rod (301) is fixedly fitted with a first fixing frame (401) and two first reinforcing plates (601). A lifting block (403) is fixedly installed on one side of the first fixing frame (401) and the second fixing frame (402).

9. A silicon wafer cleaning apparatus according to claim 8, characterized in that: The second fixing frame (402) and the second reinforcing plate (602) are both fixedly connected to the second guide rod (302) and rotate in cooperation with the bidirectional lead screw (501). The first fixing frame (401) and the first reinforcing plate (601) are both fixedly connected to the two first guide rods (301). The adjustment assembly (5) also includes a rotating shaft (502) and a handle (503). The rotating shaft (502) is fixedly connected to one end of the bidirectional lead screw (501), and the handle (503) is fixedly connected to the rotating shaft (502). The first fixing frame (401) is sleeved in the middle position of the rotating shaft (502) and the second guide rod (302), and the second fixing frame (402) is sleeved in the middle position of the two first guide rods (301).

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