Manufacturing method of square quartz substrate

Abstract

The invention provides a method for manufacturing a square quartz substrate, which comprises the following steps of: cutting a square quartz substrate blank to be processed into blank pieces by using a cutting machine, then respectively carrying out profiling contour grinding on each piece, and carrying out double-sided coarse grinding and accurate grinding on two large surfaces of a square quartz substrate workpiece according to the thickness removal amount and roughness requirements; placing the square quartz substrate workpiece subjected to double-sided accurate grinding on a side edge polishing machine carrying table, and polishing the four side surfaces of the square quartz substrate workpiece at the same time; the square quartz substrate workpiece with the side face polished is loaded in a polishing jig of a double-face polishing machine, double-face rough polishing, medium polishing and fine polishing are conducted on the two large faces of the square quartz substrate workpiece respectively, and the thickness removal amount, roughness and surface quality requirements of all procedures are met; and the polished square quartz substrate workpiece is placed in an ultrasonic cleaning machine to be cleaned and detected, and the square quartz substrate workpiece is cleaned and packaged after being detected to be qualified. The method is mainly completed by combining the working procedures of single-line cutting, multi-line cutting, CNC profiling, double-face grinding, side edge polishing, double-face polishing, ultrasonic cleaning and the like, the method is suitable for manufacturing high-flatness, low-roughness and low-defect quartz glass substrates, the complete manufacturing technological process and specification of the quartz glass substrates are established through batch machining, sampling inspection and full inspection, and the production efficiency of the quartz glass substrates is improved. The processing efficiency and the yield of the product are improved, and the quartz substrate is particularly suitable for a photomask plate used in a semiconductor associated electronic material and belongs to the technical field of ultra-precision processing.

Description

Technical Field

[0001] The invention discloses a method for manufacturing a square quartz substrate, and particularly relates to the technical field of photomask quartz substrate processing. Background Art

[0002] In photolithography, the mask, also known as the photomask, is a master template for pattern transfer in the microelectronics manufacturing process and is widely used in semiconductors, flat panel displays, printed circuit boards and other fields. The function of the mask is similar to the "negative" of a traditional camera. Its role is to transfer the designed circuit pattern to the photoresist film on the wafer or quartz substrate through processes such as photolithography, development, and etching with the cooperation of the photolithography machine and photoresist, so as to replicate the circuit pattern and achieve mass production. The most important raw material in the mask is the mask substrate. As the carrier of the mask pattern, the mask substrate plays an important role in the precision and quality of the mask product. The substrate must have good optical transmittance, size and chemical stability, flatness, etc., and no minor defects such as sand inclusions and bubbles. Due to the stable chemical properties, high optical transmittance and low thermal expansion coefficient of quartz glass, it has become the mainstream raw material for preparing mask quartz substrates in recent years.

[0003] At present, the production process of photomask quartz substrates on the market has a long processing cycle and low processing efficiency, and the quartz substrate products on the market can only meet optical-grade or low-precision application scenarios. There is no complete product quality requirement that meets the semiconductor lithography level, including its production process and quality control process that meet the requirements. The product flatness and surface quality control are poorly controlled and can no longer meet the batch processing and supply needs of a large number of square quartz semiconductor substrates. Summary of the invention

[0004] The object of the present invention is to provide a method for manufacturing a square quartz substrate which can improve the processing quality of the product.

[0005] The present invention is achieved in that:

[0006] The present invention provides a method for manufacturing a square quartz substrate, which is characterized by comprising the following steps:

[0007] S1. Cut the square quartz substrate blank to be processed into blank pieces by a cutting machine. The thickness difference between each piece and the thickness difference between each piece should be TTV≤25um, the surface roughness should be Ra<1um, and there should be no obvious line marks on the cutting surface.

[0008] S2, grinding the cut square quartz substrate workpiece blank according to the finished product specifications, specifically grinding the length, width and chamfer of the cut square quartz substrate workpiece using a CNC engraving machine;

[0009] S3, loading the square quartz substrate workpiece that has completed the profile grinding into the double-sided grinding machine grinding fixture, and performing rough grinding and fine grinding on the two large surfaces of the square quartz substrate workpiece according to the thickness removal amount and roughness requirements, and the process environment is required to be a dust-free clean workshop;

[0010] S4, loading the double-sided fine grinding square quartz substrate workpiece on the side polishing machine carrier, and polishing the four sides of the square quartz substrate workpiece at the same time, and the process environment is required to be a Class 10,000 clean workshop;

[0011] S5. Load the square quartz substrate workpiece that has completed side polishing into the polishing fixture of the double-sided polishing machine, and perform double-sided rough polishing, medium polishing, and fine polishing on the two large surfaces of the square quartz substrate workpiece according to the thickness removal amount and roughness requirements, and the process environment is required to be a Class 1000 clean workshop;

[0012] S6. Place the polished square quartz substrate workpiece in an ultrasonic cleaning machine for cleaning and testing. After passing the test, it will be cleanly packaged, and the process environment is required to be a Class 100 clean workshop.

[0013] According to the above technical solution, in step S1, a single-wire saw and a multi-wire saw are used to cut the quartz substrate blank into individual pieces.

[0014] According to the above technical solution, in step S2, a diamond grinding tool with a particle size of 400# to 1200# is used in combination with a CNC engraving machine to perform contour grinding on the square quartz substrate workpiece cut into a blank; wherein the grinding tool spindle speed is 10000r / min to 20000r / min, and the cutting depth is 0.05 to 0.5mm.

[0015] According to the above technical scheme, in step S3, rough grinding is performed according to the thickness removal amount and roughness requirements; the grinding powder adopts one of artificial corundum, silicon carbide, aluminum oxide, and artificial diamond, the particle size of the grinding powder for rough grinding is W7-W14, the solid content of the powder liquid after being prepared into the grinding liquid is 25%-35%, and the rough grinding pressure is 75-100g / cm 2 The speed of the double-sided grinder is 15-25r / min, the coarse grinding time is 1H-3H, and the process environment is required to be a dust-free clean workshop.

[0016] According to the above technical scheme, in step S3, fine grinding is performed according to the thickness removal amount and roughness requirements; the grinding powder is one of artificial corundum, silicon carbide, aluminum oxide, and artificial diamond; the particle size of the grinding powder for fine grinding is W2.5-W7, and the solid content of the powder liquid after being prepared into the grinding liquid is 15%-25%, and the fine grinding pressure is 50-75g / cm 2 The speed of the double-sided grinder is 10-20r / min, the fine grinding time is 0.5H-1H, and the process environment is required to be a dust-free clean workshop.

[0017] According to the above technical scheme, in step S4, the type of powder for side polishing is selected from one of ferric oxide polishing powder, cerium-rare earth oxide polishing powder, and zirconium oxide polishing powder; the particle size of the polishing powder for side polishing is W2.5~W7, and the solid content of the powder liquid after being prepared into the side polishing liquid is 25%~35%, the type of polishing wheel is polyurethane foam plastic or polytetrafluoroethylene polishing material, the speed of the side polishing machine is 600r / min~1200r / min, and the time is 2H~3H.

[0018] According to the above technical scheme, in step S5, the type of polishing powder for double-sided rough polishing is selected from cerium-rare earth oxide polishing powder and zirconium oxide polishing powder, the center particle size of the polishing powder is 1.5-2.1um, the solid content of the polishing liquid prepared for rough polishing is 20%-30%, the type of polishing pad is polyurethane foam plastic or polytetrafluoroethylene polishing material, the hardness of the polishing pad is Shore A66-90, the compression rate of the polishing pad is 3.4-8.3%, and the rough polishing pressure is 80-120g / cm 2 The speed of the double-sided polishing machine is 15-25r / min, the temperature is 20℃-25℃, the rough polishing time is 3H-4H, and the pH value of the rough polishing liquid is PH9-12.

[0019] According to the above technical scheme, in step S5, the type of polishing powder for double-sided medium polishing is selected from one of cerium-rare earth oxide and zirconium oxide polishing powder liquid, the central particle size of the polishing powder liquid is 0.2-0.9um, the solid content of the polishing liquid prepared for medium polishing is 10%-20%, the type of polishing pad is a polyurethane foam pad, the hardness of the polishing pad is Shore Asker C 60-70, the compression rate of the polishing pad is 4-7%, the opening diameter is 50-80um, the grinding layer thickness is 500-700um, and the medium polishing pressure is 60-100g / cm 2 The speed of the double-sided polishing machine is 10-20r / min, the temperature is 20℃-25℃, the medium polishing time is 1H-2H, the pH value of the medium polishing liquid is 8.0-10.0, and the process environment is required to be a Class 1000 clean workshop.

[0020] According to the above technical scheme, in step S5, the type of polishing liquid for double-sided fine polishing is selected from one of cerium-rare earth oxide polishing liquid and silicon oxide polishing liquid, the central particle size of the polishing liquid is 0.04-0.1um, the solid content of the polishing liquid prepared for fine polishing is 5%-15%, the type of polishing pad is polyurethane foam pad, the hardness of the polishing pad is Shore Asker C 37-55, the compression rate is 9.0-24%, the opening diameter is 20-120um, the grinding layer thickness is 400-600um, and the fine polishing pressure is 40-80g / cm 2The speed of the double-sided polishing machine is 10-15r / min, the temperature is 20℃-25℃, the fine polishing time is 0.5-1.0H, the PH value of the fine polishing liquid is 7.0-9.0, and the process environment is required to be a Class 1000 clean workshop.

[0021] According to the above technical solution, the measuring equipment used in step S5 includes an automatic image measuring instrument and an atomic force microscope; wherein the automatic image measuring instrument selects an AOI image measuring instrument and a flatness measuring instrument.

[0022] According to the above technical scheme, in step S6, the tank ultrasonic cleaning process environment is a Class 100 clean workshop, and the types of cleaning agents can be selected from alkaline cleaning agents (PH 10-12) and acidic cleaning agents (PH 4-6), with concentrations of 2%-5% respectively, and the ultrasonic frequency is 20kHz to 130kHz in stages. The water used for rinsing and preparing cleaning agents is national standard EW-I electronic grade water, and the ultrasonic time is set at 3 to 10 minutes, and the temperature is set at 22 to 50°C. It is required that after cleaning, KLA, Lasertec, LAZIN and other defect detection equipment be used to detect defects on the surface. The product surface particle size is not more than 50 particles above 0.2um, and the particles above 0.5um are not more than 20. There are no defects above 1um (pits, protruding particles, etc.), and metal ions are less than 5E10 atoms / square centimeter. After the inspection is completed, clean packaging is carried out, wherein the substrate pieces used for macro index (flatness, roughness) sampling in steps S3-S5 do not enter the clean packaging;

[0023] The beneficial effects of the present invention are as follows: the present invention is mainly completed by a combination of single-line and multi-line cutting, CNC profiling, double-sided rough grinding, fine grinding and polishing, side polishing, double-sided rough polishing, medium polishing, fine polishing, ultrasonic cleaning and other process steps, and is suitable for the production of high-flatness, low-roughness and low-defect quartz glass substrates. Through batch processing, random inspection and full inspection, the product processing efficiency and yield are improved, especially meeting the requirements of photomask quartz substrates used in semiconductor-related electronic materials, and belonging to the field of ultra-precision processing technology. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 The present invention is a flowchart provided in an embodiment of the present invention. DETAILED DESCRIPTION

[0025] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Generally, the components of the embodiments of the present invention described and shown in the drawings here can be arranged and designed in various different configurations.

[0026] Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the invention claimed for protection, but merely represents selected embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0027] The features and performance of the present invention are further described in detail below in conjunction with the embodiments.

[0028] Example 1

[0029] This embodiment provides a method for manufacturing a square quartz substrate, comprising the following steps:

[0030] S1. Use a cutting machine to cut the quartz substrate blank to be processed into shape, requiring the thickness difference between each piece and the thickness difference between each piece TTV≤25um, the surface roughness Ra<1um, and no obvious line marks on the cutting surface;

[0031] The cutting step is specifically divided into two steps. First, a single-wire cutting machine is used to cut the quartz ingot blank into single pieces. The square is cut according to the process size requirements by controlling the feed speed, tension, cutting line speed, etc. of the single-wire cutting machine, and the length, width and total thickness of the quartz blank to be processed are detected by a vernier caliper; then, the quartz blank ingot is evenly cut in the thickness direction by a multi-wire cutting machine, and the thickness slices are cut according to the process size requirements by controlling the cutting wire diameter, feed speed, tension, cutting line speed, etc., and there are no obvious cutting marks on the surface;

[0032] S2, the cut square quartz substrate workpiece is subjected to profiling profile grinding (CNC profiling) according to the product specifications, specifically, the length, width, height and chamfer of the cut square quartz substrate workpiece are ground by a CNC engraving machine; specifically, a grinding tool with a particle size of 400# to 1200# is used to perform profile grinding on the square quartz substrate workpiece cut into blanks, wherein the grinding tool spindle speed is 12000r / min, and the cutting depth is 0.1mm, wherein the length, width and chamfer of the square quartz substrate workpiece are detected by a vernier caliper and an R gauge;

[0033] S3, loading the square quartz substrate workpiece that has completed the profile grinding into the double-sided grinding machine grinding fixture, and performing rough grinding and fine grinding on the two large surfaces of the square quartz substrate workpiece according to the thickness removal amount and roughness requirements to ensure the thickness, and the process environment is required to be a dust-free clean workshop;

[0034] Among them, during rough grinding: rough grinding is carried out according to the thickness removal and roughness requirements, such as the removal requirement of 0.2mm-0.3mm, the surface roughness requirement of Ra<0.2um, and the thickness difference TTV≤3um. The grinding powder is one of artificial corundum, silicon carbide, aluminum oxide, and artificial diamond; the particle size of the grinding powder is W7, the solid content of the powder liquid after being prepared into the grinding liquid is 25%, and the rough grinding pressure is 75g / cm 2 , the speed of the double-sided grinder is 15r / min, and the rough grinding time is 3H; the process environment is required to be a dust-free clean workshop; after the rough grinding, a micrometer is used to detect the thickness of the single piece and its thickness difference; a portable surface roughness measuring instrument is used to detect the surface roughness, and a strong light (120,000-300,000 Lx illumination) is used to transmit the workpiece to check its surface quality, and the surface is required to be free of scratches and other abnormal defects.

[0035] Fine grinding: Fine grinding is carried out according to the thickness removal and roughness requirements, such as thickness removal of 0.05-0.1mm, surface roughness requirement Ra<0.1um, thickness difference requirement TTV≤1um; the grinding powder uses artificial corundum, silicon carbide, aluminum oxide, and artificial diamond; the particle size of the grinding powder for fine grinding is W2.5, the solid content of the powder liquid after being prepared into the grinding liquid is 15%, and the fine grinding pressure is 50g / cm 2 The speed of the double-sided grinder is 10r / min, and the fine grinding time is 1H; the process environment is required to be a dust-free clean workshop; after fine grinding, a micrometer is used to detect the thickness of the single piece and its thickness difference; a portable surface roughness measuring instrument is used to detect the surface roughness, and a strong light (120,000-300,000 Lx illumination) is used to transmit the workpiece to check its surface quality, and the surface is required to be free of scratches and other abnormal defects.

[0036] S4. Load the double-sided fine grinding square quartz substrate workpiece onto the side polishing machine platform, and polish the four sides of the square quartz substrate workpiece at the same time to ensure that the side roughness Ra≤0.02um. Among them, the type of polishing powder is selected from ferric oxide polishing powder, cerium-rare earth oxide polishing powder, and zirconium oxide polishing powder; the particle size of the polishing powder for side polishing is W2.5, and the solid content of the powder liquid after preparing the side polishing liquid is 25%. The type of polishing wheel is polyurethane foam plastic or polytetrafluoroethylene polishing material, the speed of the side polishing machine is 600r / min, and the time is 3H. The process environment is a 10,000-level clean workshop. After the side polishing is completed, a portable surface roughness measuring instrument is used to detect the side surface roughness Ra≤0.02um, and a strong light (120,000-300,000 Lx illumination) is used to transmit the workpiece to check its surface quality, and the surface is required to be free of scratches and other abnormal defects.

[0037] S5. Load the square quartz substrate workpiece that has completed side polishing into the polishing fixture of the double-sided polishing machine, and perform double-sided rough polishing, medium polishing, and fine polishing on the two large surfaces of the square quartz substrate workpiece according to the thickness removal amount and roughness requirements, and the process environment is required to be a Class 1000 clean workshop;

[0038] During the rough polishing process, the type of polishing powder for double-sided rough polishing can be selected from cerium-rare earth oxide polishing powder and zirconium oxide polishing powder. The center particle size of the polishing powder is 1.5, the solid content of the polishing liquid prepared for rough polishing is 20%, the type of polishing pad is polyurethane foam plastic or polytetrafluoroethylene polishing material, the hardness of the polishing pad is Shore A66, the compression rate of the polishing pad is 3.4, and the rough polishing pressure is 80g / cm 2 The speed of the double-sided polishing machine is 15r / min, the temperature is 20℃, the rough polishing time is 4H, the pH value of the rough polishing liquid is PH9, and the process environment is required to be a Class 1000 clean workshop; the thickness removal amount is required to be guaranteed after rough polishing, such as 0.05mm-0.08mm, flatness <3um and roughness Ra≤1nm. Among them, the measurement equipment used includes automatic image measuring instruments (such as AOI image measuring instruments, flatness measuring instruments (Corning Tropel Flat Master), atomic force microscopes (BrukerAFM), etc.); a strong light (120,000-300,000 Lx illumination) is used to transmit the workpiece to check its surface quality from multiple angles, and the surface is required to be free of abnormal defects such as scratches.

[0039] During the medium polishing process, the type of polishing powder for double-sided medium polishing can be selected from cerium-rare earth oxide and zirconium oxide polishing powder liquid. The center particle size of the polishing powder liquid is 0.2um. The solid content of the polishing liquid prepared for medium polishing is 10%. The type of polishing pad is polyurethane foam pad. The hardness of the polishing pad is Shaw Asker C 60, the compression rate of the polishing pad is 4%, the opening diameter is 50um, the grinding layer thickness is 500um, and the medium polishing pressure is 60g / cm 2 The speed of the double-sided polishing machine is 10r / min, the temperature is 20℃, the polishing time is 2H, the pH value of the polishing liquid is 8.0, and the process environment is required to be a Class 1000 clean workshop. The thickness removal is required to be guaranteed after polishing, such as 0.01mm-0.04mm, flatness <1um and roughness Ra≤0.5nm. Among them, the measuring equipment used includes automatic image measuring instruments (such as AOI image measuring instruments, flatness measuring instruments (Corning Tropel FlatMaster), atomic force microscopes (Bruker AFM), etc.); a strong light (120,000-300,000 Lx illumination) is used to transmit the workpiece to check its surface quality from multiple angles, and the surface is required to be free of abnormal defects such as scratches.

[0040] During the fine polishing process, one of the cerium-rare earth oxide polishing liquid and the silicon oxide polishing liquid can be selected. The center particle size of the polishing liquid is 0.04um. The solid content of the polishing liquid prepared for fine polishing is 5%. The type of polishing pad is a polyurethane foam pad. The hardness of the polishing pad is Shaw Asker C 37, the compression rate is 9.0%, the opening diameter is 20um, the grinding layer thickness is 400um, and the fine polishing pressure is 40g / cm 2 The speed of the double-sided polishing machine is 10r / min, the temperature is 20℃, the fine polishing time is 1H, the pH value of the fine polishing liquid is 7.0, and the process environment is required to be a Class 1000 clean workshop. The thickness removal amount is required to be guaranteed after fine polishing, such as 0.002mm-0.005mm, flatness <1um and roughness Ra≤0.2nm. Among them, the measuring equipment used includes automatic image measuring instruments (such as AOI image measuring instruments, flatness measuring instruments (Corning Tropel Flat Master), atomic force microscopes (Bruker AFM), etc., and a strong light (120,000-300,000 Lx illumination) is used to transmit the workpiece to check its surface quality from multiple angles, and the surface is required to be free of abnormal defects such as scratches.

[0041] S6. Place the square quartz substrate workpiece that has completed side polishing in an ultrasonic cleaning machine for deep cleaning and testing. The macro indicators (length, width, thickness, flatness, roughness, etc.) are tested by random inspection, and defects are fully inspected. After passing the inspection, they are cleanly packaged.

[0042] Among them, a fully automatic ultrasonic cleaning machine is used for tank-type multi-piece ultrasonic cleaning. The types of cleaning agents can be selected from alkaline cleaning agents (PH pH 10) and acidic cleaning agents (PH pH 4), the concentration is prepared using 2%, the ultrasonic frequency is matched in stages from 20kHz to 130kHz, the water used for rinsing and preparing cleaning agents uses national standard EW-I electronic grade water, the ultrasonic time is set at 3-10 minutes, and the temperature is set at 22°C to 45°C.

[0043] Next, after cleaning, the surface is required to be inspected for defects using defect detection equipment such as KLA, Lasertec, and LAZIN. The number of particles on the product surface with a particle size of more than 0.2um shall not exceed 50, and the number of particles with a particle size of more than 0.5um shall not exceed 20. There shall be no defects (pits, raised particles, etc.) larger than 1um, and the metal ions shall be less than 5E10 atoms / square centimeter.

[0044] Finally, the clean packaging is carried out after being treated with clean nitrogen on the clean packaging workbench. The substrates used for macro index (flatness, roughness) sampling test in steps S3-S5 do not enter the clean packaging;

[0045] The present invention is mainly completed by combining single-line and multi-line cutting, CNC profiling, double-sided grinding and polishing, side polishing and other process steps, and is suitable for the production of high-flatness, low-roughness and low-defect quartz glass substrates. Through batch processing, random inspection and full inspection, the product processing efficiency and yield are improved, especially meeting the requirements of photomask quartz substrates used in semiconductor-related electronic materials, and belongs to the field of ultra-precision processing technology.

[0046] Example 2

[0047] This embodiment provides a method for manufacturing a square quartz substrate, comprising the following steps:

[0048] S1. Use a cutting machine to cut the quartz substrate blank to be processed into shape, requiring the thickness difference between each piece and the thickness difference between each piece TTV≤25um, the surface roughness Ra<1um, and no obvious line marks on the cutting surface;

[0049] The cutting step is specifically divided into two steps. First, a single-wire cutting machine is used to cut the quartz ingot blank into single pieces. The square is cut according to the process size requirements by controlling the feed speed, tension, cutting line speed, etc. of the single-wire cutting machine, and the length, width and total thickness of the quartz blank to be processed are detected by a vernier caliper; then, the quartz blank ingot is evenly cut in the thickness direction by a multi-wire cutting machine, and the thickness slices are cut according to the process size requirements by controlling the cutting wire diameter, feed speed, tension, cutting line speed, etc., and there are no obvious cutting marks on the surface;

[0050] S2, the cut square quartz substrate workpiece is subjected to profiling profile grinding (CNC profiling) according to the product specifications, specifically, the length, width, height and chamfer of the cut square quartz substrate workpiece are ground by a CNC engraving machine; specifically, a grinding tool with a particle size of 400# to 1200# is used to perform profile grinding on the square quartz substrate workpiece cut into blanks, wherein the grinding tool spindle speed is 10000r / min to 20000r / min, and the cutting depth is 0.1-0.5mm, wherein the length, width and chamfer of the square quartz substrate workpiece are detected by a vernier caliper and an R gauge;

[0051] S3, loading the square quartz substrate workpiece that has completed the profile grinding into the double-sided grinding machine grinding fixture, and performing rough grinding and fine grinding on the two large surfaces of the square quartz substrate workpiece according to the thickness removal amount and roughness requirements to ensure the thickness, and the process environment is required to be a dust-free clean workshop;

[0052] Among them, during rough grinding: rough grinding is carried out according to the thickness removal and roughness requirements, such as the removal requirement of 0.2mm-0.3mm, the surface roughness requirement of Ra<0.2um, and the thickness difference TTV≤3um. The grinding powder is one of artificial corundum, silicon carbide, aluminum oxide, and artificial diamond; the particle size of the grinding powder is W14, the solid content of the powder liquid after being prepared into the grinding liquid is 35%, and the rough grinding pressure is 100g / cm 2 , the speed of the double-sided grinder is 25r / min, and the rough grinding time is 1H; the process environment is required to be a dust-free clean workshop; after the rough grinding, a micrometer is used to detect the thickness of the single piece and its thickness difference; a portable surface roughness measuring instrument is used to detect the surface roughness, and a strong light (120,000-300,000 Lx illumination) is used to transmit the workpiece to check its surface quality, and the surface is required to be free of scratches and other abnormal defects.

[0053] Fine grinding: Fine grinding is carried out according to the thickness removal and roughness requirements, such as thickness removal of 0.05-0.1mm, surface roughness requirement Ra<0.1um, thickness difference requirement TTV≤1um; the grinding powder uses artificial corundum, silicon carbide, aluminum oxide, and artificial diamond; the particle size of the grinding powder for fine grinding is W7, the solid content of the powder liquid after being prepared into the grinding liquid is 25%, and the fine grinding pressure is 75g / cm 2 The speed of the double-sided grinder is 20r / min, and the rough grinding time is 0.5H; the process environment is required to be a dust-free clean workshop; after the fine grinding, a micrometer is used to detect the thickness of the single piece and its thickness difference; a portable surface roughness measuring instrument is used to detect the surface roughness, and a strong light (120,000-300,000 Lx illumination) is used to transmit the workpiece to check its surface quality, and the surface is required to be free of scratches and other abnormal defects.

[0054] S4. Load the double-sided fine grinding square quartz substrate workpiece on the side polishing machine platform, and polish the four sides of the square quartz substrate workpiece at the same time to ensure that the side roughness Ra≤0.02um. Among them, the type of polishing powder is selected from ferric oxide polishing powder, cerium-rare earth oxide polishing powder, and zirconium oxide polishing powder; the particle size of the polishing powder for side polishing is W7, and the solid content of the powder liquid after preparing the side polishing liquid is 35%. The type of polishing wheel is polyurethane foam plastic or polytetrafluoroethylene polishing material. The speed of the side polishing machine is 1200r / min, the time is 2H, and the process environment is a 10,000-level clean workshop. After the side polishing is completed, a portable surface roughness measuring instrument is used to detect the side surface roughness Ra≤0.02um, and a strong light (120,000-300,000 Lx illumination) is used to transmit the workpiece to check its surface quality, and the surface is required to be free of scratches and other abnormal defects.

[0055] S5. Load the square quartz substrate workpiece that has completed side polishing into the polishing fixture of the double-sided polishing machine, and perform double-sided rough polishing, medium polishing, and fine polishing on the two large surfaces of the square quartz substrate workpiece according to the thickness removal amount and roughness requirements, and the process environment is required to be a Class 1000 clean workshop;

[0056] During the rough polishing process, the type of polishing powder for double-sided rough polishing can be selected from cerium-rare earth oxide polishing powder and zirconium oxide polishing powder. The center particle size of the polishing powder is 2.1um. The solid content of the polishing liquid prepared for rough polishing is 30%. The type of polishing pad is polyurethane foam plastic or polytetrafluoroethylene polishing material. The hardness of the polishing pad is Shore A90, the compression rate of the polishing pad is 8.3%, and the rough polishing pressure is 120g / cm 2 The speed of the double-sided polishing machine is 25r / min, the temperature is 25℃, the rough polishing time is 2H, the pH value of the rough polishing liquid is PH12, and the process environment is required to be a Class 1000 clean workshop; the thickness removal amount is required to be guaranteed after rough polishing, such as 0.08mm, flatness <3um and roughness Ra≤1nm. Among them, the measurement equipment used includes automatic image measuring instruments (such as AOI image measuring instruments, flatness measuring instruments (Corning Tropel Flat Master), atomic force microscopes (BrukerAFM), etc.); a strong light (120,000-300,000 Lx illumination) is used to transmit the workpiece to check its surface quality from multiple angles, and the surface is required to be free of abnormal defects such as scratches.

[0057] During the medium polishing process, the type of polishing powder for double-sided medium polishing can be selected from cerium-rare earth oxide and zirconium oxide polishing powder liquid. The center particle size of the polishing powder liquid is 0.9um. The solid content of the polishing liquid prepared for medium polishing is 20%. The type of polishing pad is polyurethane foam pad. The hardness of the polishing pad is Shaw Asker C 70, the compression rate of the polishing pad is 7%, the opening diameter is 80um, the grinding layer thickness is 700um, and the medium polishing pressure is 100g / cm 2 The speed of the double-sided polishing machine is 20r / min, the temperature is 25℃, the polishing time is 1H, the pH value of the polishing liquid is 10.0, and the process environment is required to be a Class 1000 clean workshop. The thickness removal is required to be guaranteed after polishing, such as 0.01mm-0.04mm, flatness <1um and roughness Ra≤0.5nm. Among them, the measuring equipment used includes automatic image measuring instruments (such as AOI image measuring instruments, flatness measuring instruments (Corning Tropel FlatMaster), atomic force microscopes (Bruker AFM), etc.); a strong light (120,000-300,000 Lx illumination) is used to transmit the workpiece to check its surface quality from multiple angles, and the surface is required to be free of abnormal defects such as scratches.

[0058] During the fine polishing process, one of the cerium-rare earth oxide polishing liquid and the silicon oxide polishing liquid can be selected. The center particle size of the polishing liquid is 0.1um. The solid content of the polishing liquid prepared for fine polishing is 15%. The type of polishing pad is a polyurethane foam pad. The hardness of the polishing pad is Shaw Asker C 55, the compression rate is 24%, the opening diameter is 120um, the grinding layer thickness is 600um, and the fine polishing pressure is 80g / cm 2 The speed of the double-sided polishing machine is 15r / min, the temperature is 25℃, the fine polishing time is 0.5H, the pH value of the fine polishing liquid is 9.0, and the process environment is required to be a Class 1000 clean workshop. The thickness removal amount is required to be guaranteed after fine polishing, such as 0.002mm-0.005mm, flatness <1um and roughness Ra≤0.2nm. Among them, the measuring equipment used includes automatic image measuring instruments (such as AOI image measuring instruments, flatness measuring instruments (Corning Tropel Flat Master), atomic force microscopes (Bruker AFM), etc., and a strong light (120,000-300,000 Lx illumination) is used to transmit the workpiece to check its surface quality from multiple angles, and the surface is required to be free of abnormal defects such as scratches.

[0059] S6. Place the square quartz substrate workpiece that has completed side polishing in an ultrasonic cleaning machine for deep cleaning and testing. The macro indicators (length, width, thickness, flatness, roughness, etc.) are tested by random inspection, and defects are fully inspected. After passing the inspection, they are cleanly packaged.

[0060] Among them, a fully automatic ultrasonic cleaning machine is used for tank-type multi-piece ultrasonic cleaning. The type of cleaning agent can be an alkaline cleaning agent (PH acidity 10-12), the concentration is prepared using 5%, the ultrasonic frequency is matched in stages of 20kHz to 130kHz, and the water used for rinsing and preparing the cleaning agent is national standard EW-I grade electronic grade water. The ultrasonic time is set at 3 to 10 minutes, and the temperature is set at 22°C to 45°C.

[0061] Next, after cleaning, the surface is required to be inspected for defects using defect detection equipment such as KLA, Lasertec, and LAZIN. The number of particles on the product surface with a particle size of more than 0.2um shall not exceed 50, and the number of particles with a particle size of more than 0.5um shall not exceed 20. There shall be no defects (pits, raised particles, etc.) larger than 1um, and the metal ions shall be less than 5E10 atoms / square centimeter.

[0062] Finally, the clean packaging is carried out after being treated with clean nitrogen on the clean packaging workbench. The substrates used for macro index (flatness, roughness) sampling test in steps S3-S5 do not enter the clean packaging;

[0063] Example 3

[0064] This embodiment provides a method for manufacturing a square quartz substrate, comprising the following steps:

[0065] S1. Use a cutting machine to cut the quartz substrate blank to be processed into shape, requiring the thickness difference between each piece and the thickness difference between each piece TTV≤25um, the surface roughness Ra<1um, and no obvious line marks on the cutting surface;

[0066] The cutting step is specifically divided into two steps. First, a single-wire cutting machine is used to cut the quartz ingot blank into single pieces. The square is cut according to the process size requirements by controlling the feed speed, tension, cutting line speed, etc. of the single-wire cutting machine, and the length, width and total thickness of the quartz blank to be processed are detected by a vernier caliper; then, the quartz blank ingot is evenly cut in the thickness direction by a multi-wire cutting machine, and the thickness slices are cut according to the process size requirements by controlling the cutting wire diameter, feed speed, tension, cutting line speed, etc., and there are no obvious cutting marks on the surface;

[0067] S2, the cut square quartz substrate workpiece is subjected to profiling profile grinding (CNC profiling) according to the product specifications, specifically, the length, width, height and chamfer of the cut square quartz substrate workpiece are ground by a CNC engraving machine; specifically, a grinding tool with a particle size of 400# to 1200# is used to perform profile grinding on the square quartz substrate workpiece cut into blanks, wherein the grinding tool spindle speed is 18000r / min, and the cutting depth is 0.3mm, wherein the length, width and chamfer of the square quartz substrate workpiece are detected by a vernier caliper and an R gauge;

[0068] S3, loading the square quartz substrate workpiece that has completed the profile grinding into the double-sided grinding machine grinding fixture, and performing rough grinding and fine grinding on the two large surfaces of the square quartz substrate workpiece according to the thickness removal amount and roughness requirements to ensure the thickness, and the process environment is required to be a dust-free clean workshop;

[0069] Among them, during rough grinding: rough grinding is carried out according to the thickness removal and roughness requirements, such as the removal requirement of 0.2mm-0.3mm, the surface roughness requirement of Ra<0.2um, and the thickness difference TTV≤3um. The grinding powder is one of artificial corundum, silicon carbide, aluminum oxide, and artificial diamond; the particle size of the grinding powder is W30, and the solid content of the powder liquid after being prepared into the grinding liquid is 31%, and the rough grinding pressure is 85g / cm 2 , the speed of the double-sided grinder is 18r / min, and the rough grinding time is 2H; the process environment is required to be a dust-free clean workshop; after the rough grinding, a micrometer is used to detect the thickness of the single piece and its thickness difference; a portable surface roughness measuring instrument is used to detect the surface roughness, and a strong light (120,000-300,000 Lx illumination) is used to transmit the workpiece to check its surface quality, and the surface is required to be free of scratches and other abnormal defects.

[0070] Fine grinding: Fine grinding is carried out according to the thickness removal and roughness requirements, such as thickness removal of 0.05-0.1mm, surface roughness requirement Ra<0.1um, thickness difference requirement TTV≤1um; the grinding powder uses artificial corundum, silicon carbide, aluminum oxide, and artificial diamond; the particle size of the grinding powder for fine grinding is W4, the solid content of the powder liquid after being prepared into the grinding liquid is 17%, and the fine grinding pressure is 60g / cm 2 The speed of the double-sided grinder is 15r / min, and the rough grinding time is 0.8H; the process environment is required to be a dust-free clean workshop; after the fine grinding, a micrometer is used to detect the thickness of the single piece and its thickness difference; a portable surface roughness measuring instrument is used to detect the surface roughness, and a strong light (120,000-300,000 Lx illumination) is used to transmit the workpiece to check its surface quality, and the surface is required to be free of scratches and other abnormal defects.

[0071] S4. Load the double-sided fine grinding square quartz substrate workpiece on the side polishing machine platform, and polish the four sides of the square quartz substrate workpiece at the same time to ensure that the side roughness Ra≤0.02um. Among them, the type of polishing powder is selected from ferric oxide polishing powder, cerium-rare earth oxide polishing powder, and zirconium oxide polishing powder; the particle size of the polishing powder for side polishing is W2.5~W7, and the solid content of the powder liquid after preparing the side polishing liquid is 30%. The type of polishing wheel is polyurethane foam plastic or polytetrafluoroethylene polishing material, and the speed of the side polishing machine is 800r / min and the time is 2.5H. The process environment is a 10,000-level clean workshop. After the side polishing is completed, a portable surface roughness measuring instrument is used to detect the side surface roughness Ra≤0.02um, and a strong light (120,000-300,000 Lx illumination) is used to transmit the workpiece to check its surface quality, and the surface is required to be free of scratches and other abnormal defects.

[0072] S5. Load the square quartz substrate workpiece that has completed side polishing into the polishing fixture of the double-sided polishing machine, and perform double-sided rough polishing, medium polishing, and fine polishing on the two large surfaces of the square quartz substrate workpiece according to the thickness removal amount and roughness requirements, and the process environment is required to be a Class 1000 clean workshop;

[0073] During the rough polishing process, the type of polishing powder for double-sided rough polishing can be selected from cerium-rare earth oxide polishing powder and zirconium oxide polishing powder. The center particle size of the polishing powder is 1.8um. ​​The solid content of the polishing liquid prepared for rough polishing is 25%. The type of polishing pad is polyurethane foam plastic or polytetrafluoroethylene polishing material. The hardness of the polishing pad is Shore A80. The compression rate of the polishing pad is 5.5%. The rough polishing pressure is 100g / cm 2The speed of the double-sided polishing machine is 20r / min, the temperature is 23℃, the rough polishing time is 3.5H, the pH value of the rough polishing liquid is PH10, and the process environment is required to be a Class 1000 clean workshop; the thickness removal amount is required to be guaranteed after rough polishing, such as 0.05mm-0.08mm, flatness <3um and roughness Ra≤1nm. Among them, the measurement equipment used includes automatic image measuring instruments (such as AOI image measuring instruments, flatness measuring instruments (Corning Tropel Flat Master), atomic force microscopes (Bruker AFM), etc.); a strong light (120,000-300,000 Lx illumination) is used to transmit the workpiece to check its surface quality from multiple angles, and the surface is required to be free of abnormal defects such as scratches.

[0074] During the medium polishing process, the type of polishing powder for double-sided medium polishing can be selected from cerium-rare earth oxide and zirconium oxide polishing powder liquid. The center particle size of the polishing powder liquid is 0.6um. The solid content of the polishing liquid prepared for medium polishing is 15%. The type of polishing pad is polyurethane foam pad. The hardness of the polishing pad is Shaw Asker C 65, the compression rate of the polishing pad is 5%, the opening diameter is 60um, the grinding layer thickness is 600um, and the medium polishing pressure is 80g / cm 2 The speed of the double-sided polishing machine is 15r / min, the temperature is 23℃, the polishing time is 1.5H, the pH value of the polishing liquid is 9.0, and the process environment is required to be a Class 1000 clean workshop. The thickness removal is required to be guaranteed after polishing, such as 0.01mm-0.04mm, flatness <1um and roughness Ra≤0.5nm. Among them, the measuring equipment used includes automatic image measuring instruments (such as AOI image measuring instruments, flatness measuring instruments (Corning Tropel FlatMaster), atomic force microscopes (Bruker AFM), etc.); a strong light (120,000-300,000 Lx illumination) is used to transmit the workpiece to check its surface quality from multiple angles, and the surface is required to be free of abnormal defects such as scratches.

[0075] During the fine polishing process, one of the cerium-rare earth oxide polishing liquid and the silicon oxide polishing liquid can be selected. The center particle size of the polishing liquid is 0.08um. The solid content of the polishing liquid prepared for fine polishing is 10%. The type of polishing pad is a polyurethane foam pad. The hardness of the polishing pad is Shaw Asker C 40, the compression rate is 15%, the opening diameter is 70um, the grinding layer thickness is 500um, and the fine polishing pressure is 60g / cm 2The speed of the double-sided polishing machine is 13r / min, the temperature is 23℃, the fine polishing time is 0.65H, the pH value of the fine polishing liquid is 8.0, and the process environment is required to be a Class 1000 clean workshop. The thickness removal amount is required to be guaranteed after fine polishing, such as 0.002mm-0.005mm, flatness <1um and roughness Ra≤0.2nm. Among them, the measuring equipment used includes automatic image measuring instruments (such as AOI image measuring instruments, flatness measuring instruments (Corning Tropel Flat Master), atomic force microscopes (Bruker AFM), etc., and a strong light (120,000-300,000 Lx illumination) is used to transmit the workpiece to check its surface quality from multiple angles, and the surface is required to be free of abnormal defects such as scratches.

[0076] S6. Place the square quartz substrate workpiece that has completed side polishing in an ultrasonic cleaning machine for deep cleaning and testing. The macro indicators (length, width, thickness, flatness, roughness, etc.) are tested by random inspection, and defects are fully inspected. After passing the inspection, they are cleanly packaged.

[0077] Among them, a fully automatic ultrasonic cleaning machine is used for tank-type multi-piece ultrasonic cleaning. The types of cleaning agents can be selected from alkaline cleaning agents (PH pH 11) and acidic cleaning agents (PH pH 5), the concentration is prepared using 4%, the ultrasonic frequency is matched in stages from 20kHz to 130kHz, and the water used for rinsing and preparing cleaning agents uses national standard EW-I electronic grade water. The ultrasonic time is set at 6 minutes and the temperature is set at 22°C to 45°C.

[0078] Next, after cleaning, the surface is required to be inspected for defects using defect detection equipment such as KLA, Lasertec, and LAZIN. The number of particles on the product surface with a particle size of more than 0.2um shall not exceed 50, and the number of particles with a particle size of more than 0.5um shall not exceed 20. There shall be no defects (pits, raised particles, etc.) larger than 1um, and the metal ions shall be less than 5E10 atoms / square centimeter.

[0079] Finally, the clean packaging is carried out after being treated with clean nitrogen on the clean packaging workbench. The substrates used for macro index (flatness, roughness) sampling test in steps S3-S5 do not enter the clean packaging;

[0080] The embodiments described above are part of the embodiments of the present invention, rather than all of the embodiments. The detailed description of the embodiments of the present invention is not intended to limit the scope of the invention claimed for protection, but merely represents selected embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

Claims

1. A method for manufacturing a square quartz substrate, characterized in that: The steps include: S1. Cut the square quartz substrate blank to be processed into blank pieces by a cutting machine. The thickness difference between each piece and the thickness difference between each piece should be TTV≤25um, the surface roughness should be Ra<1um, and there should be no obvious line marks on the cutting surface. S2, grinding the cut square quartz substrate workpiece blank according to the finished product specifications, specifically grinding the length, width and chamfer of the cut square quartz substrate workpiece using a CNC engraving machine; S3, loading the square quartz substrate workpiece that has completed the profile grinding into the double-sided grinding machine grinding fixture, and performing rough grinding and fine grinding on the two large surfaces of the square quartz substrate workpiece according to the thickness removal amount and roughness requirements, and the process environment is required to be a dust-free clean workshop; S4, loading the double-sided fine grinding square quartz substrate workpiece on the side polishing machine carrier, and polishing the four sides of the square quartz substrate workpiece at the same time, and the process environment is required to be a Class 10,000 clean workshop; S5. Load the square quartz substrate workpiece that has completed side polishing into the polishing fixture of the double-sided polishing machine, and perform rough polishing, medium polishing, and fine polishing on the two large surfaces of the square quartz substrate workpiece according to the thickness removal amount and roughness requirements, and the process environment is required to be a Class 1000 clean workshop; S6. Place the polished square quartz substrate workpiece in an ultrasonic cleaning machine for cleaning and testing. After passing the test, it will be cleanly packaged, and the process environment is required to be a Class 100 clean workshop.

2. The method for manufacturing a square quartz substrate according to claim 1 or 2, characterized in that: In step S1, a single-wire saw and a multi-wire saw are used to cut the quartz substrate blank into individual pieces.

3. The method for manufacturing a square quartz substrate according to claim 1 or 2, characterized in that: In step S2, a diamond grinding tool with a particle size of 400# to 1200# is used in combination with a CNC engraving machine to perform contour grinding on the square quartz substrate workpiece cut into blanks; wherein the grinding tool spindle speed is 10000r / min to 20000r / min, and the cutting depth is 0.05 to 0.5mm.

4. The method for manufacturing a square quartz substrate according to claim 1 or 2, characterized in that: In step S3, rough grinding is performed according to the thickness removal amount and roughness requirements; the grinding powder is one of artificial corundum, silicon carbide, aluminum oxide, and artificial diamond, the particle size of the grinding powder for rough grinding is W7-W14, the solid content of the powder liquid after being prepared into the grinding liquid is 25%-35%, and the rough grinding pressure is 75-100g / cm 2 The speed of the double-sided grinder is 15-25r / min, the coarse grinding time is 1H-3H, and the process environment is required to be a dust-free clean workshop.

5. The method for manufacturing a square quartz substrate according to claim 1 or 2, characterized in that: In step S3, fine grinding is performed according to the thickness removal amount and roughness requirements; the grinding powder is one of artificial corundum, silicon carbide, aluminum oxide, and artificial diamond; the particle size of the grinding powder for fine grinding is W2.5-W7, and the solid content of the powder liquid after being prepared into the grinding liquid is 15%-25%, and the fine grinding pressure is 50-75g / cm 2 The speed of the double-sided grinder is 10-20r / min, the fine grinding time is 0.5H-1H, and the process environment is required to be a dust-free clean workshop.

6. The method for manufacturing a square quartz substrate according to claim 1 or 2, characterized in that: In step S4, the type of powder for side polishing is selected from one of ferric oxide polishing powder, cerium-rare earth oxide polishing powder, and zirconium oxide polishing powder; the particle size of the polishing powder for side polishing is W2.5~W7, and the solid content of the powder liquid after being prepared into the side polishing liquid is 25%~35%, the type of polishing wheel is polyurethane foam plastic or polytetrafluoroethylene polishing material, the speed of the side polishing machine is 600r / min~1200r / min, and the time is 2H~3H.

7. The method for manufacturing a square quartz substrate according to claim 1 or 2, characterized in that: In step S5, the type of polishing powder for double-sided rough polishing is selected from cerium-rare earth oxide polishing powder and zirconium oxide polishing powder, the center particle size of the polishing powder is 1.5-2.1um, the solid content of the polishing liquid prepared for rough polishing is 20%-30%, the type of polishing pad is polyurethane foam plastic or polytetrafluoroethylene polishing material, the hardness of the polishing pad is Shore A66-90, the compression rate of the polishing pad is 3.4-8.3%, and the rough polishing pressure is 80-120g / cm 2 The speed of the double-sided polishing machine is 15-25r / min, the temperature is 20℃-25℃, the rough polishing time is 3H-4H, and the pH value of the rough polishing liquid is PH9-12.

8. The method for manufacturing a square quartz substrate according to claim 1 or 2, characterized in that: In step S5, the type of polishing powder for double-sided medium polishing is selected from one of cerium-rare earth oxide and zirconium oxide polishing powder liquid, the central particle size of the polishing powder liquid is 0.2-0.9um, the solid content of the polishing liquid prepared for medium polishing is 10%-20%, the type of polishing pad is polyurethane foam pad, the hardness of the polishing pad is Shore Asker C 60-70, the compression rate of the polishing pad is 4-7%, the opening diameter is 50-80um, the grinding layer thickness is 500-700um, and the medium polishing pressure is 60-100g / cm 2 The speed of the double-sided polishing machine is 10-20r / min, the temperature is 20℃-25℃, the medium polishing time is 1H-2H, the pH value of the medium polishing liquid is 8.0-10.0, and the process environment is required to be a Class 1000 clean workshop.

9. The method for manufacturing a square quartz substrate according to claim 1 or 2, characterized in that: In step S5, the type of polishing liquid for double-sided fine polishing is selected from one of cerium-rare earth oxide polishing liquid and silicon oxide polishing liquid, the central particle size of the polishing liquid is 0.04-0.1um, the solid content of the polishing liquid prepared for fine polishing is 5%-15%, the type of polishing pad is polyurethane foam pad, the hardness of the polishing pad is Shore Asker C 37-55, the compression rate is 9.0-24%, the opening diameter is 20-120um, the grinding layer thickness is 400-600um, and the fine polishing pressure is 40-80g / cm 2 The speed of the double-sided polishing machine is 10-15r / min, the temperature is 20℃-25℃, the fine polishing time is 0.5-1.0H, the pH value of the fine polishing liquid is 7.0-9.0, and the measuring equipment used in step S5 includes an automatic image measuring instrument and an atomic force microscope; among them, the automatic image measuring instrument selects an AOI image measuring instrument and a flatness measuring instrument.

10. The method for manufacturing a square quartz substrate according to claim 1 or 2, characterized in that: In step S6, the type of cleaning agent is alkaline cleaning agent or acidic cleaning agent, and the concentration is prepared by 2%-5%, the ultrasonic frequency is matched in stages of 20kHz-130kHz, the water used for rinsing and preparing the cleaning agent is national standard EW-I electronic grade water, the ultrasonic time is set at 3-10min, the temperature is set at 22-50℃, and it is required that after cleaning, the surface particle size of the product is not more than 50 particles above 0.2um, the particle size above 0.5um is not more than 20, there is no defect above 1um, and the metal ion is less than 5E10 atoms / square centimeter; after the inspection is completed, clean packaging is carried out, wherein the substrate pieces used for macro index sampling in steps S3-S5 do not enter the clean packaging.

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