Recycling method of bad patterned substrate

Abstract

The invention relates to the technical field of semiconductors, and discloses a recycling method of an undesirable patterned substrate, the bottom width of the undesirable patterned substrate is smaller than a preset value, and the recycling method comprises the following steps: cleaning the surface of the classified undesirable patterned substrate with the bottom width smaller than the preset value for the first time, and keeping the undesirable patterned substrate dry; etching the bad patterned substrate cleaned for the first time so as to widen the bottom width of the bad patterned substrate; wherein in the etching process, the upper radio frequency power ranges from 1000 W to 1400 W, the lower radio frequency power ranges from 180 W to 250 W, the etching gas is BCl3 and Cl2, the flow of the etching gas ranges from 80 sccm to 120 sccm, the flow of the auxiliary gas ranges from 2 sccm to 6 sccm, and the etching time ranges from 100 s to 300 s. By implementing the method, the rejection rate of products caused by small bottom width can be reduced, secondary utilization of bad patterned substrate products is realized, the process loss is reduced, the shipment rate is improved, and the rework rate after the patterned substrate is etched is reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of semiconductors, and in particular to a method for recycling defective patterned substrates. Background Art

[0002] As is well known, the production process of patterned sapphire substrates is complex and affected by various factors. For example, process fluctuations, substrate type switching, and machine stop and restart situations will inevitably result in defective product dimensions, and it is easy to produce edge Pin defects in product dimensions. In the inspection process, product dimensions are classified into large size, small size, oversized, undersized, and micro-defect levels through optical principles. For products with a large bottom width, a unified method of pulling them back for secondary etching is usually adopted to solve the problem. Although the proportion of scrapped parts with a small size is only 0.005%, in the long run, the quantity corresponding to this proportion cannot be underestimated, which will cause significant economic losses to the enterprise.

[0003] Currently, for products with a small bottom width, they are often directly scrapped, and then flat polishing or substrate thinning and other rework operations are carried out before being fed back for reuse. However, this method of dealing with products with a small bottom width has obvious drawbacks. It not only reduces the production and shipment rate, but also increases the rework cost and extends the material turnover cycle. In view of the above situation, it is urgent to formulate effective improvement measures for the "scrapped" wafer sources produced in the conventional patterned substrate process to reduce process losses and improve the product shipment rate. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to provide a method for recycling defective patterned substrates, which can realize the secondary utilization of abnormal patterned substrates, has a short recycling period, and improves the shipment rate of patterned substrates.

[0005] To solve the above technical problem, in the first aspect of the present invention, a method for recycling defective patterned substrates is provided. The bottom width of the defective patterned substrate is less than a preset value, and the method includes:

[0006] (1) Perform the first size measurement and classification on the defective patterned substrate;

[0007] (2) Perform the first cleaning on the surface of the classified defective patterned substrate with a bottom width less than the preset value, and keep it dry;

[0008] (3) Etch the defective patterned substrate after the first cleaning to widen the bottom width of the defective patterned substrate;

[0009] Wherein, when performing the etching, the upper radio frequency power is 1000W - 1400W, the lower radio frequency power is 180W - 250W, and the etching gas is BCl 3 and Cl 2, the total flow rate of the etching gas is 80 sccm - 120 sccm, the flow rate of the auxiliary gas is 2 sccm - 6 sccm, and the etching time is 100 s - 300 s;

[0010] (4) Perform a second cleaning on the patterned substrate obtained after etching and keep it dry;

[0011] (5) Perform a second dimensional measurement on the patterned substrate after the second cleaning and perform AOI gaging.

[0012] As an improvement to the above solution, the widening width W1 of the bottom width of the defective patterned substrate, the bottom width of the defective patterned substrate is W2, and W1 = (3% - 10%)W2.

[0013] As an improvement to the above solution, W1 = 100 nm - 200 nm.

[0014] As an improvement to the above solution, in the etching gas, BCl 3 and Cl 2 have a volume ratio of (2 - 4):1.

[0015] As an improvement to the above solution, when performing the etching, the upper RF power is 1100 W - 1300 W, the lower RF power is 190 W - 240 W, the flow rate of the auxiliary gas is 3 sccm - 5 sccm, and the etching gas is BCl 3 and Cl 2 , the flow rate of the etching gas is 90 sccm - 110 sccm, and the etching time is 120 s - 280 s.

[0016] As an improvement to the above solution, when performing the etching, the flow rate of the auxiliary gas is 3 sccm - 5 sccm, and the auxiliary gas is helium.

[0017] As an improvement to the above solution, the first cleaning includes:

[0018] Clean the surface of the defective patterned substrate with a bottom width less than the preset value using an acid solution to remove impurities and foreign matters on the surface, and then flush with water to remove the residual acid solution on the surface;

[0019] Among them, the acid solution is a mixture of H 2 SO 4 and H 2 O 2 , and the volume ratio of H 2 SO 4 and H 2 O 2 is (3 - 4):1.

[0020] As an improvement of the above solution, when performing the first cleaning, the cleaning temperature is 110°C - 140°C, the cleaning time is 550s - 650s; the flushing time is 500s - 600s.

[0021] As an improvement of the above solution, the second cleaning includes:

[0022] Using an acid solution to clean the surface of the defective patterned substrate to remove impurities and foreign matters on the surface, and then flushing with water to remove the residual acid solution on the surface;

[0023] Among them, the acid solution is a mixed solution of H 2 SO 4 and H 2 O 2 with a volume ratio of (3 - 4):1. The cleaning temperature is 110°C - 140°C, the cleaning time is 550s - 650s; the flushing time is 500s - 600s.

[0024] As an improvement of the above solution, an atomic force microscope is used to perform the first size measurement on the defective patterned substrate, and the measurement parameters include the bottom width, height, and radian;

[0025] An atomic force microscope is used to perform the second size measurement on the defective patterned substrate, and the measurement parameters include the bottom width, height, and radian..

[0026] Implementing the present invention has the following beneficial effects:

[0027] In this application, by performing additional etching on the defective patterned substrate with a bottom width less than the preset value, the rejection rate of products caused by a small bottom width can be reduced, and the secondary utilization of the defective patterned substrate products that have been "scrapped" can be realized. Moreover, compared with the traditional recycling technologies such as thinning and polishing used for defective patterned substrates, the recycling method in this application is more efficient, greatly shortening the recycling cycle of the substrate, improving the effective utilization rate and turnover rate of the substrate, thereby reducing the process loss, increasing the shipping rate, and reducing the rework rate after etching of the patterned substrate. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 : Comparison chart of the bottom width values of the first size test and the second size test in Example 1 of the present invention;

[0029] Figure 2 : Comparison chart of the height values of the first size test and the second size test in Example 1 of the present invention;

[0030] Figure 3 : Comparison chart of the radian values of the first size test and the second size test in Example 1 of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0031] To make the objectives, technical solutions, and advantages of the present invention clearer, the following specific embodiments will be used to further describe the present invention in detail.

[0032] In the conventional etching process, to meet the production capacity requirements, the etching machine of North China Technology usually adopts parameter settings of high etching power and high gas flow rate. Specifically, the upper electrode power ranges from 1000W to 1400W, the lower electrode power is from 400W to 800W, the helium gas flow rate is from 4sccm to 8sccm, and the BCl 3 flow rate is from 80sccm to 130sccm. At the same time, it is paired with the yellow light photoresist condition window to achieve the etching requirements. However, this high-power and high-flow etching method further increases the risk of product size defects to a certain extent.

[0033] To solve the above problems, the present invention provides a method for recycling defective patterned substrates, where the bottom width of the defective patterned substrate is less than a preset value, including:

[0034] (1) Conduct the first size measurement and classification on the defective patterned substrate;

[0035] (2) Conduct the first cleaning on the surface of the defective patterned substrate with a bottom width less than the preset value after classification, and keep it dry;

[0036] (3) Etch the defective patterned substrate after the first cleaning to widen the bottom width of the defective patterned substrate;

[0037] Among them, when conducting the etching, the upper radio frequency power is from 1000W to 1400W, the lower radio frequency power is from 180W to 250W, the etching gas is BCl 3 and Cl 2 , the total flow rate of the etching gas is from 80sccm to 120sccm, the auxiliary gas flow rate is from 2sccm to 6sccm, and the etching time is from 100s to 300s;

[0038] (4) Conduct the second cleaning on the patterned substrate obtained after etching, and keep it dry;

[0039] (5) Conduct the second size test on the patterned substrate after the second cleaning, and conduct a conventional AOI gage.

[0040] In this application, by performing supplementary etching on a defective patterned substrate with a bottom width less than a preset value, the rejection rate of products caused by a small bottom width can be reduced, realizing the secondary utilization of defective patterned substrate products that have undergone "rejection" treatment. Moreover, compared with the traditional recycling technologies such as thinning and polishing for defective patterned substrates, the recycling method in this application is more efficient, greatly shortening the recycling cycle of the substrate, improving the effective utilization rate and turnover rate of the substrate, thereby reducing process losses, increasing the shipping rate, and reducing the rework rate after etching the patterned substrate.

[0041] The following is a specific elaboration for each step:

[0042] Regarding (1), perform the first size measurement and classification on the defective patterned substrate;

[0043] In this step, use an atomic force microscope to perform the first size measurement on the defective patterned substrate. The measurement parameters include the bottom width, height, and radian. Subsequently, classify the defective patterned substrates according to the bottom width, height, and radian parameters. Exemplarily, defective patterned substrates with a bottom width greater than the preset value, and height and radian close to the preset value can be classified as Class A1; defective patterned substrates with a bottom width less than the preset value, and height and radian close to the preset value can be classified as Class A2; defective patterned substrates with a height greater than the preset value, and bottom width and radian close to the preset value can be classified as Class B1; defective patterned substrates with a height less than the preset value, and bottom width and radian close to the preset value can be classified as Class B2; defective patterned substrates with a radian greater than the preset value, and bottom width and height close to the preset value can be classified as Class C1; defective patterned substrates with a radian less than the preset value, and bottom width and height close to the preset value can be classified as Class C2; defective patterned substrates with a bottom width, height, and radian all greater than the preset value can be classified as Class D1; defective patterned substrates with a bottom width, height, and radian all less than the preset value can be classified as Class D2.

[0044] Optionally, the defective patterned substrate is a sapphire substrate.

[0045] Regarding (2), perform the first cleaning on the surface of the classified defective patterned substrates with a bottom width less than the preset value and keep it dry;

[0046] In this step, the first cleaning of the surface of the classified defective patterned substrates with a bottom width less than the preset value includes: using an acid solution to clean the surface of the defective patterned substrates with a bottom width less than the preset value to remove impurities and foreign matters on the surface, and then flushing with water to remove the residual acid solution on the surface.

[0047] Preferably, the acid solution is H 2 SO 4 and H 2 O 2 mixed solution, which has strong oxidizing properties, H 2SO 4 and H 2 O 2 can react with and remove various metal impurities, and at the same time quickly remove the organic substances on the surface of the substrate, such as photoresist residues, grease, organic pollutants, etc., effectively removing various types of impurities with good cleaning effect, and there will be no residual organic or metal pollutants interfering with the etching reaction after cleaning, thereby improving the uniformity, selectivity and controllability of etching, contributing to promoting the precise widening of the bottom width. In addition, H 2 SO 4 and H 2 O 2 are both easily available, with high economy and practicability.

[0048] Furthermore, the volume ratio of H 2 SO 4 to H 2 O 2 is (3 - 4):1. H 2 SO 4 provides a suitable acidic environment for H 2 O 2 , increasing the oxidizing property of H 2 O 2 , with better cleaning effect, and can control the corrosion degree of the acid solution on the substrate within a reasonable range, ensuring the structural integrity and surface quality of the substrate, which is beneficial to the subsequent etching process. If the content of H 2 SO 4 is too high, it will corrode the substrate excessively, resulting in changes in the microscopic structure of the substrate surface. During subsequent etching, the contact area and reaction active points between the etchant and the substrate increase, which may accelerate the etching rate and make it difficult to control, affecting the etching accuracy and the accuracy of the pattern; if the content of H 2 O 2 is too high, while removing impurities, it can better maintain the flatness and smoothness of the substrate surface, providing a more ideal surface state for subsequent etching, but it will make the organic or metal impurities unable to be completely oxidized and dissolved, and the residual impurities will hinder the contact between the etchant and the substrate during the etching process, resulting in uneven etching rate and deviation of the etched pattern, reducing the selectivity and uniformity of etching.

[0049] Furthermore, when performing the first cleaning, the cleaning temperature is 110°C - 140°C, the cleaning time is 550s - 650s, and the flushing time is 500s - 600s. At this time, the decomposition rate of H 2 O 2 is fast, and more strongly oxidizing hydroxyl radicals can be generated, reacting with H 2 SO 4The synergistic effect greatly enhances the oxidation ability of the mixed solution, further enhancing the cleaning effect, fully exposing the active sites on the substrate surface, facilitating the uniform contact and reaction between the subsequent etchant and the substrate, and accelerating the cleaning rate. The cleaning time can be controlled within 550 s - 650 s. Moreover, it accelerates the conversion of various impurities into soluble substances, which detach from the substrate surface. The flushing time of 500 s - 600 s can remove the acid solution and impurities on the substrate surface.

[0050] Optionally, the methods for keeping the defective patterned substrate dry after the first cleaning include, but are not limited to, spin-drying, and the spin-drying time can be 600 s - 720 s.

[0051] Regarding (3), etching the defective patterned substrate after the first cleaning to widen the bottom width of the defective patterned substrate;

[0052] In this step, when performing the etching, the upper radio frequency power is 1000 W - 1400 W, the lower radio frequency power is 180 W - 250 W, the etching gas is BCl 3 and Cl 2 , and the etching time is 100 s - 300 s. In this application, by reducing the lower radio frequency power and using a low frequency to etch the defective patterned substrate, ions can obtain more appropriate energy, enabling the ions to bombard the substrate surface, widen the bottom width, and not overly affect the height and curvature of the substrate due to excessive ion energy. This helps to achieve precise etching, and is also conducive to the more uniform transmission and distribution of ions in the plasma, avoiding some uncontrollable side reactions generated during high-frequency processing, ensuring relatively consistent bombardment of ions at various positions on the substrate surface, and better controlling the widening of the bottom width. Subsequently, in combination with the etching gases BCl 3 and Cl 2 , an auxiliary gas is introduced, but not CHF 3 , which has good selectivity and controllable chemical reactions on the defective patterned substrate, enabling the etching process to proceed at the expected rate and direction, facilitating the precise control of the etching width. Moreover, BCl 3 can form a certain passivation layer on the sidewalls of the substrate during the etching process, preventing it from being overly eroded during the etching process, thus helping to maintain the curvature and height of the substrate, and making the etching mainly focus on widening the bottom width. More preferably, when performing the etching, the upper radio frequency power is 1100 W - 1300 W, the lower radio frequency power is 190 W - 240 W, the etching gas is BCl 3 and Cl 2 , and the etching time is 120 s - 280 s. Optionally, the auxiliary gas is helium.

[0053] Furthermore, in the etching gas, BCl 3 and Cl 2The volume ratio is (2 - 4):1, the total flow rate of the etching gas is 80 sccm - 120 sccm, and the flow rate of the auxiliary gas is 2 sccm - 6 sccm, which further promotes that the etching rate in the direction perpendicular to the substrate surface is relatively greater than that in other horizontal directions, ensures the expansion of the bottom width, and maintains the stability of the height and arc while not reaching the scrapping condition. If the flow rate of BCl 3 is low, the etching rate becomes slow, and there is insufficient material for sidewall passivation and participation in the reaction, which may not effectively protect the sidewalls, resulting in poor etching directionality and affecting the arc and height; if the flow rate of Cl 2 is low, too much BCl 3 may inhibit the etching reaction, reduce the etching rate, and cannot effectively widen the bottom width. More preferably, when performing the etching, the volume ratio of BCl 3 and Cl 2 in the etching gas is (2.5 - 3.5):1, the total flow rate of the etching gas is 90 sccm - 110 sccm, and the flow rate of the auxiliary gas is 3 sccm - 5 sccm.

[0054] Furthermore, through the above etching, the widened width W1 of the bottom width of the defective patterned substrate, and the bottom width of the defective patterned substrate is W2, such that W1 = (3% - 10%)W2. Exemplarily, W1 = 3% * W2, W1 = 5% * W2, W1 = 7% * W2, W1 = 9% * W2, W1 = 10% * W2. In some specific and preferred embodiments, W1 is 100 nm - 200 nm, and the height and arc dimensions do not decrease significantly, not reaching the scrapping compartment, realizing the secondary recycling of the defective patterned substrate.

[0055] Regarding (4), the patterned substrate obtained after etching is subjected to a second cleaning and kept dry;

[0056] In this step, the second cleaning includes: cleaning the surface of the defective patterned substrate with an acid solution to remove foreign impurities on the surface, and then flushing with water to remove the residual acid solution on the surface; wherein, the acid solution is a mixture of H 2 SO 4 and H 2 O 2 with a volume ratio of (3 - 4):1, which can effectively remove foreign impurities generated during the etching process.

[0057] Further, the cleaning temperature is 110°C - 140°C, the cleaning time is 550 s - 650 s; the flushing time is 500 s - 600 s, which can accelerate the cleaning rate and control the cleaning time to 550 s - 650 s. Moreover, it is beneficial for various impurities to be converted into solutes and quickly detached from the substrate surface, and the flushing time of 500 s - 600 s can remove the acid solution and impurities on the substrate surface.

[0058] Optionally, the methods for drying the defective patterned substrate after the second cleaning include, but are not limited to, spin-drying, and the spin-drying time can be 600 s - 720 s.

[0059] Regarding (5), perform a second size test on the patterned substrate after the second cleaning and conduct AOI gaging.

[0060] In this step, use an atomic force microscope to perform a second size measurement on the defective patterned substrate. The measurement parameters include the bottom width, height, and radian. Subsequently, perform AOI gaging on the patterned substrate that meets the parameter requirements. Through the second size measurement, it can be found that for a defective patterned substrate with a bottom width less than the preset value, by using a specific low frequency and etching gas, the bottom width of the substrate can be increased, and the height and radian remain almost unchanged, so as to meet the shipping requirements and improve the product yield.

[0061] The present invention will be further described below with specific examples:

[0062] Example 1

[0063] This example provides a method for recycling defective patterned substrates, including:

[0064] (1) Use an atomic force microscope to perform a first size measurement on the defective patterned sapphire substrate. The measurement parameters include the bottom width, height, and radian. Subsequently, classify the defective patterned substrates according to the bottom width, height, and radian parameters;

[0065] (2) Use an acid solution to perform a first cleaning on the surface of the defective patterned substrate with a bottom width less than the preset value after classification to remove foreign impurities on the surface. Subsequently, flush with water to remove the residual acid solution on the surface and spin-dry; wherein, the acid solution is a mixture of H 2 SO 4 and H 2 O 2 , and the volume ratio of H 2 SO 4 and H 2 O 2 is 4:1, the cleaning temperature is 130°C, the cleaning time is 600 s, and the flushing time is 550 s;

[0066] (3) Etch the defective patterned substrate after the first cleaning to widen the bottom width of the defective patterned substrate; wherein, when performing the etching, the upper radio frequency power is 1200 W, the lower radio frequency power is 190 W, and the etching gas is BCl 3 and Cl 2 , the total flow rate is 100 sccm, and the volume ratio of BCl 3 and Cl 2 is 3.5:1, the etching time is 240 s, the auxiliary gas is helium, and the flow rate of the auxiliary gas is 4 sccm;

[0067] (4) Use an acid solution to perform a second cleaning on the patterned substrate obtained after etching to remove foreign impurities on the surface, then rinse with water to remove the residual acid solution on the surface, and spin dry; wherein, the acid solution is a mixture of H 2 SO 4 and H 2 O 2 , and the volume ratio of H 2 SO 4 and H 2 O 2 is 4:1, the cleaning temperature is 130 °C, the cleaning time is 600 s, and the rinsing time is 550 s;

[0068] (5) Perform a second dimensional test on the patterned substrate after the second cleaning, and the measured parameters include the bottom width, height, and radian. Subsequently, according to the bottom width, height, and radian parameters, then perform AOI gaging on the patterned substrate that meets the parameter requirements.

[0069] Compare and analyze the numerical values of the bottom width, height, and radian of the first dimensional test with those of the second dimensional test. As Figures 1 - 3 shown, it is found that using the method in this application to process the defective patterned substrate can widen the bottom width of the defective patterned substrate by about 100 nm, and the height and radian remain almost unchanged, meeting the shipping requirements.

[0070] Example 2

[0071] This example provides a method for recycling defective patterned substrates, which is basically the same as Example 1, except that:

[0072] In step (3), the lower radio frequency power is 250 W, and the etching gas is BCl 3 and Cl 2 , the total flow rate is 80 sccm, and the etching time is 150 s.

[0073] Compare and analyze the bottom width, height, and radian of the first size test with those of the second size test. It is found that by using the method in this application to process the defective patterned substrate, the bottom width of the defective patterned substrate can be widened by about 90 nm, and the height and radian remain almost unchanged, meeting the shipping requirements.

[0074] Example 3

[0075] This example provides a method for recycling defective patterned substrates, which is basically the same as Example 1, except that:

[0076] In step (2), the acid solution is a mixture of H 2 SO 4 and H 2 O 2 , and the volume ratio of H 2 SO 4 to H 2 O 2 is 3:1;

[0077] In step (3), the lower radio frequency power is 220 W, the etching gas is BCl 3 and Cl 2 , the total flow rate is 120 sccm, and the etching time is 200 s.

[0078] Compare and analyze the bottom width, height, and radian of the first size test with those of the second size test. It is found that by using the method in this application to process the defective patterned substrate, the bottom width of the defective patterned substrate can be widened by about 95 nm, and the height and radian remain almost unchanged, meeting the shipping requirements.

[0079] Example 4

[0080] This example provides a method for recycling defective patterned substrates, which is basically the same as Example 1, except that:

[0081] In step (2), the acid solution is a mixture of H 2 SO 4 and H 2 O 2 , and the volume ratio of H 2 SO 4 to H 2 O 2 is 5:1.

[0082] Compare and analyze the bottom width, height, and radian values of the first size test with those of the second size test. It is found that when using the method in this application to process the defective patterned substrate, the bottom width of the defective patterned substrate can be widened by about 90 nm, and the height and radian also change, not meeting the shipping requirements.

[0083] Comparative Example 1

[0084] This comparative example provides a method for recycling defective patterned substrates, which is basically the same as Example 1, except that:

[0085] In step (3), the lower radio frequency power is 500 W.

[0086] Compare and analyze the bottom width, height, and radian values of the first size test with those of the second size test. It is found that when using the method in this application to process the defective patterned substrate, the bottom width of the defective patterned substrate can be widened by about 110 nm, and the height and radian also change, not meeting the shipping requirements.

[0087] Comparative Example 2

[0088] This comparative example provides a method for recycling defective patterned substrates, which is basically the same as Example 1, except that:

[0089] In step (3), the etching gas is BCl 3 , Cl 2 and CHF 3 , and the flow rate ratio of BCl 3 , Cl 2 and CHF 3 is 1:1:1.

[0090] Compare and analyze the bottom width, height, and radian values of the first size test with those of the second size test. It is found that when using the method in this application to process the defective patterned substrate, the bottom width of the defective patterned substrate can be widened by about 70 nm, and the height and radian also change, not meeting the shipping requirements.

[0091] Through the comparative analysis of the examples and comparative examples in this application, it can be known that for defective patterned substrates with a bottom width less than the preset value, by using specific low frequencies and etching gases, the bottom width of the substrate can be increased, and the height and radian are almost unchanged, meeting the shipping requirements, improving the product yield, realizing the secondary utilization of defective patterned substrate products, and having a short recycling period.

[0092] The above-disclosed is only a preferred embodiment of the present invention, and of course, it cannot be used to limit the scope of the rights of the present invention. Therefore, equivalent changes made according to the claims of the present invention still fall within the scope covered by the present invention.

Claims

1. A method for recycling a defective patterned substrate, characterized in that: The bottom width of the defective patterned substrate is smaller than a preset value, including: (1) Perform the first dimension measurement and classification of defective patterned substrates; (2) performing a first cleaning on the surface of the classified defective patterned substrate whose bottom width is smaller than a preset value and keeping it dry; (3) etching the poorly patterned substrate after the first cleaning to widen the bottom width of the poorly patterned substrate; Wherein, when performing the etching, the upper RF power is 1000W-1400W, the lower RF power is 180W-250W, the etching gas is BCl3 and Cl2, the total flow rate of the etching gas is 80sccm-120sccm, the flow rate of the auxiliary gas is 2sccm-6sccm, and the etching time is 100s-300s; (4) cleaning the patterned substrate obtained after etching for a second time and keeping it dry; (5) Perform a second size test on the patterned substrate after the second cleaning and perform AOI grading.

2. The method for recycling a defective patterned substrate according to claim 1, wherein: The expanded width of the bottom width of the poorly patterned substrate is W1, and the bottom width of the poorly patterned substrate is W2, where W1 = (3% - 10%) W2.

3. The method for recycling a defective patterned substrate according to claim 2, wherein: W1=100nm-200nm.

4. The method for recycling a defective patterned substrate according to claim 1, wherein: The volume ratio of BCl3 and Cl2 in the etching gas is (2-4):

1.

5. The method for recycling a defective patterned substrate according to claim 3, characterized in that: When performing the etching, the upper RF power is 1100W-1300W, the lower RF power is 190W-240W, the flow rate of the auxiliary gas is 3sccm-5sccm, the etching gas is BCl3 and Cl2, the flow rate of the etching gas is 90sccm-110sccm, and the etching time is 120s-280s.

6. The method for recycling a defective patterned substrate according to claim 4 or 5, characterized in that: When performing the etching, the flow rate of the auxiliary gas is 3sccm-5sccm, and the auxiliary gas is helium.

7. The method for recycling a defective patterned substrate according to claim 6, wherein: The first cleaning comprises: The surface of the defective patterned substrate with a bottom width smaller than a preset value is cleaned with an acid solution to remove impurities and foreign matter on the surface, and then the residual acid solution on the surface is removed by flushing with water; The acid solution is a mixture of H2SO4 and H2O2, and the volume ratio of H2SO4 to H2O2 is (3-4):

1.

8. The method for recycling a defective patterned substrate according to claim 7, wherein: When performing the first cleaning, the cleaning temperature is 110° C.-140° C., the cleaning time is 550s-650s; and the flushing time is 500s-600s.

9. The method for recycling a defective patterned substrate according to claim 1, wherein: The second cleaning comprises: The surface of the poorly patterned substrate is cleaned with an acid solution to remove impurities and foreign matter on the surface, and then the residual acid solution on the surface is removed by flushing with water; The acid solution is a mixture of H2SO4 and H2O2 in a volume ratio of (3-4):1, the cleaning temperature is 110°C-140°C, the cleaning time is 550s-650s; the flushing time is 500s-600s.

10. The method for recycling a defective patterned substrate according to claim 1, wherein: Using an atomic force microscope to perform a first dimension measurement on the defective patterned substrate, the measurement parameters including bottom width, height, and curvature; An atomic force microscope is used to perform a second dimension measurement on the defective patterned substrate, and the measurement parameters include bottom width, height, and curvature.

Images