Photoresist coating method and coating jig

Abstract

The invention relates to a photoresist coating method and a coating jig, and the method comprises the following steps: carrying out pre-spraying on a substrate by a spray head, and obtaining the thickness of photoresist at the center of a spraying point and the edge of the spraying point of the substrate; diluting the photoresist to obtain a diluted solution of the photoresist, and applying high-frequency micro-vibration to the diluted solution to obtain a diluted solution with reduced apparent viscosity; the distance between the adjacent spraying points on the substrate is set to be equal to two times of the distance between the center of the spraying point and a middle point, the middle point is located between the center of the spraying point and the edge of the spraying point, and the photoresist thickness of the middle point is one half of the photoresist thickness of the center of the spraying point; and increasing the air pressure of the spraying environment, and spraying the diluted solution with reduced apparent viscosity on a plurality of spraying points of the substrate by using the spray head to finish spraying. According to the invention, the problem that the thickness of the photoresist at the edge of the substrate, especially an irregular substrate, is not uniform is effectively solved, and the uniformity of the photoresist coating layer of the substrate is improved, so that the yield of products is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of semiconductor processes, and in particular to a photoresist coating method and a coating jig. Background Art

[0002] Photoresist coating is one of the key process steps in semiconductor production. Common coating processes include spin coating, spraying, and casting coating, etc. Taking the spin coating process as an example, photoresist is injected into the center of the substrate, and the substrate is rotated at a set speed so that the photoresist diffuses from the center to the edge, thereby realizing uniform coating of the photoresist on the surface of the substrate. It is commonly used for coating circular substrates. Due to the process characteristics of spin coating, during the spin coating process, affected by surface tension, photoresist accumulation and uneven thickness and other edge defects often occur at the edges of the substrate. These edge defects will affect the coating uniformity of the entire substrate surface and have a certain impact on the subsequent lithography process. Therefore, after coating is completed, a washing edge operation is usually required, that is, by washing the edge, redundant substances such as photoresist at the edge of the substrate are removed, the edge defects of the substrate are reduced, and the semiconductor production yield is improved.

[0003] In recent years, semiconductor processes have no longer been limited to coating on circular substrates, and have begun to coat on rectangular / square regular substrates or irregular substrates. However, the spin coating process is not applicable to non-circular substrates because the distances from the photoresist injection center point to the edge of the non-circular substrate are not equal, and the distances that the photoresist needs to move from the center to the edge of the substrate during spin coating are not equal, resulting in uneven thickness of the coated photoresist film at the edges of the non-circular substrate. Therefore, currently, spraying and casting coating are mostly used for non-circular substrates. Although the spraying or casting process can reduce the problem of uneven distribution of photoresist at the edges of irregular substrates to a certain extent, this problem still cannot be avoided, which may affect the subsequent lithography process, and such substrates are not suitable for the washing edge process in the spin coating mode. Therefore, there is still a problem of uneven thickness of the edge coating, thereby reducing the semiconductor production yield. Summary of the Invention

[0004] To this end, the technical problem to be solved by the present invention is to overcome the problem that the spraying coating process in the prior art cannot effectively solve the problem of uneven thickness of the edge photoresist of the substrate, and further provide a photoresist coating method and a coating jig, which effectively solve the problem of uneven thickness of the edge photoresist of the substrate, especially irregular substrates, improve the uniformity of the photoresist coating on the substrate, and thus improve the product yield.

[0005] To solve the above technical problems, the present invention provides a photoresist coating method, including the following steps: Pre-spraying: The nozzle pre-sprays the substrate to obtain the photoresist thickness at the center and the edge of the spraying point of the substrate; Volatility suppression treatment: Dilute the photoresist to obtain a diluted solution of the photoresist, and apply high-frequency micro-vibrations to the diluted solution to obtain a diluted solution with reduced apparent viscosity; Set the spraying point spacing: Set the distance between adjacent spraying points on the substrate to be equal to twice the distance from the center of the spraying point to the middle point, where the middle point is located between the center of the spraying point and the edge of the spraying point, and the thickness of the photoresist at the middle point is half of the thickness of the photoresist at the center of the spraying point; Spraying treatment: Increase the air pressure in the spraying environment, and use the above-mentioned nozzle to spray the diluted solution with reduced apparent viscosity on multiple spraying points of the substrate to complete spraying.

[0006] In one embodiment of the present invention, in the volatility suppression treatment step, the air pressure in the spraying environment is increased by adding an inert gas.

[0007] In one embodiment of the present invention, in the volatility suppression treatment step, the apparent viscosity of the photoresist is reduced by shear thinning control technology, which specifically includes the following steps: Add a diluent to the photoresist and mix well to obtain a diluted solution of the photoresist, where the diluent includes acetone and propylene glycol monomethyl ether acetate.

[0008] In one embodiment of the present invention, the volume ratio of the photoresist, acetone, and propylene glycol monomethyl ether acetate is 1:1-100:1-100, and the viscosity of the diluted solution of the photoresist is 5 cp - 800 cp.

[0009] In one embodiment of the present invention, after the spraying treatment, the following operations are also required: Discharge the gas in the spraying environment into the waste gas recovery system through a vacuum pump for recovery; Reuse the volatile solvent in the spraying environment through a condensation recovery and re-extraction process; Filter the remaining photoresist solution using a filter, remove large particles, and then dissolve and use it; Restore the air pressure in the spraying environment to standard atmospheric pressure, and dry the surface of the photoresist on the substrate by heating.

[0010] In one embodiment of the present invention, the substrate after spraying is heated by hot air or infrared irradiation to volatilize the solvent on the substrate.

[0011] In one embodiment of the present invention, in the spraying treatment step, an inert gas is sprayed on the substrate as a carrier of the photoresist.

[0012] A coating jig is also provided, which positions and sprays the substrate, including, Multiple nozzles, the distance between adjacent nozzles being equal to twice the distance from the center of the spraying point to the middle point, the thickness of the photoresist at the middle point being equal to half the thickness of the photoresist at the center of the spraying point, and each nozzle being respectively aligned with one spraying point.

[0013] In an embodiment of the present invention, the coating fixture further includes A base Multiple carriers, the multiple carriers being arranged on the base for carrying the substrate, a gap being provided between adjacent carriers, and the size of the carrier being smaller than the size of the substrate; Straight positioning blocks, multiple straight positioning blocks being symmetrically arranged at both ends of the base, and the straight positioning blocks being located between adjacent substrates. Each straight positioning block has a right-angled recess formed by enclosing a vertical first abutting surface and a second abutting surface at both ends. Among them, the first abutting surface and the second abutting surface of one right-angled recess respectively abut against two right-angled sides of one substrate, and the first abutting surface and the second abutting surface of the other right-angled recess respectively abut against two right-angled sides of the other substrate.

[0014] In an embodiment of the present invention, two right-angled sides of the carrier are respectively parallel to the first abutting surface and the second abutting surface.

[0015] In an embodiment of the present invention, the base is provided with a mounting groove that is in imitation matching with the straight positioning block, the straight positioning block is arranged in the mounting groove, and the straight positioning block is provided with a ball plunger, and the ball plunger abuts against the side wall of the mounting groove.

[0016] In an embodiment of the present invention, it further includes a base provided with multiple first pins. The base is provided with a first positioning hole, the carrier is provided with a second positioning hole, the first positioning hole and the second positioning hole are coaxially arranged, and the first pin sequentially passes through the first positioning hole of the base and passes out of the second positioning hole of the carrier to support the substrate.

[0017] In an embodiment of the present invention, the base is further provided with multiple second pins parallel to the first pin. The length of the second pin is greater than the length of the first pin. The base is provided with multiple third positioning holes, and the multiple third positioning holes are located on both sides of the substrate, and the second pin passes out of the third positioning hole.

[0018] In an embodiment of the present invention, the coating fixture is arranged on an automated transportation device.

[0019] The above technical solutions of the present invention have the following advantages compared with the prior art: The photoresist coating method described in the present invention obtains the photoresist thickness at the center and edge of the substrate spraying points through pre-spraying, so as to perform superposition calculation on the photoresist thickness on the substrate surface during spraying, reducing the error of the photoresist coating thickness on the substrate; by reducing the viscosity of the photoresist, the amount of solvent used in the dilution solution is reduced, the amount of solvent volatilization is reduced, and the uniformity of the photoresist coating layer is improved; the air pressure of the environment is increased before spraying, so that the volatile solvent in the photoresist dilution solution reaches approximate saturation on the substrate surface, suppressing the non-uniformity of the coating layer caused by the rapid volatilization of the solvent; by optimizing the distance between the centers of adjacent spraying points, optimizing the distribution of the photoresist in the spraying coverage and overlapping areas, ensuring that the total thickness after superposition tends to be consistent, avoiding local over-thickness or under-thickness, thereby effectively improving the uniformity of the photoresist coating on the substrate. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] In order to make the content of the present invention easier to be clearly understood, the following further details the present invention according to specific embodiments of the present invention in conjunction with the accompanying drawings.

[0021] Figure 1 is a flowchart of the photoresist coating method described in the present invention; Figure 2 is a schematic structural diagram of the coating fixture described in the present invention; Figure 3 is Figure 2 a schematic structural diagram of the shown bearing platform, carrier platform and straight positioning block; Figure 4 is Figure 2 a schematic structural diagram of the shown base; Figure 5 is Figure 3 a schematic structural diagram of the shown straight positioning block.

[0022] Explanation of the reference numerals in the drawings: 11, bearing platform; 111, carrier platform; 112, second positioning hole; 113, gap; 114, third positioning hole; 115, installation groove; 116, handle; 12, base; 121, first pin; 122, second pin; 123, support leg; 13, straight positioning block; 131, first rectangular body; 1311, protruding member; 1312, ball plunger; 1313, first abutting surface; 132, second rectangular body; 1321, second abutting surface; 133, right-angle recess; 134, right-angle recess. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0023] The following further illustrates the present invention in conjunction with the accompanying drawings and specific embodiments, so that those skilled in the art can better understand the present invention and be able to implement it, but the embodiments cited do not limit the present invention. Embodiment

[0024] Refer toFigure 1 As shown, the present invention discloses a photoresist coating method, which coats the photoresist on the surface of a substrate based on a spraying process, including the following steps: Pre-spraying: The nozzle pre-sprays the substrate to obtain the photoresist thickness at the center and the edge of the spraying point on the substrate; Volatilization inhibition treatment: Dilute the photoresist to obtain a diluted solution of the photoresist, and apply high-frequency micro-vibration to the diluted solution to obtain a diluted solution with reduced apparent viscosity; Set the spraying point spacing: Set the distance between adjacent spraying points on the substrate to be equal to twice the distance from the center of the spraying point to the midpoint, where the midpoint is located between the center and the edge of the spraying point, and the photoresist thickness at the midpoint is half of the photoresist thickness at the center of the spraying point; Spraying treatment: Increase the air pressure in the spraying environment, and use the above nozzle to spray the diluted solution with reduced apparent viscosity on multiple spraying points of the substrate to complete the spraying.

[0025] In the photoresist coating method described in this embodiment, since the change in the photoresist thickness from the center to the edge of the spraying point on the substrate is approximately normally distributed, the photoresist distribution between adjacent spraying points is improved by optimizing the spacing between the centers of adjacent spraying points. For example, the photoresist thickness at the center of the spraying point is 10 microns, and the photoresist thickness at a certain midpoint between the center and the edge of the spraying point is 5 microns. Assuming that the distance between this midpoint and the center of the spraying point is 2 cm, then the distance between the centers of adjacent spraying points is set to 4 cm. According to the superposition principle, the total thickness of the photoresist at any point between the centers of adjacent spraying points approaches 10 microns after superposition. This optimizes the thickness of the photoresist covering and overlapping areas between adjacent spraying points, makes the total thickness of the photoresist between adjacent spraying points close to uniform, effectively improves the overall uniformity of the substrate coating layer, and further reduces the problem of uneven photoresist thickness at the irregular substrate edge. Further, when using a single nozzle for reciprocating coating, the starting position of each spraying is moved parallel by 4 cm. When using multiple nozzles for simultaneous coating, the distance between adjacent nozzles is set to 4 cm. To further improve the uniformity of the substrate coating layer, the viscosity of the photoresist is also reduced, thereby reducing the amount of volatile solvent in the photoresist solution and reducing the coating layer non-uniformity caused by solvent volatilization; increasing the air pressure in the spraying environment can make the volatile solvent in the diluted photoresist solution reach approximately saturation on the substrate surface, further reducing the solvent volatilization rate and reducing the coating layer non-uniformity caused by rapid solvent volatilization.

[0026] In one embodiment of the present invention, the distance between the centers of adjacent spray points is L, and the distance between the center of the spray point and the middle point is L1, then L=2*L1, the center of the spray point is located at the center of the normally distributed photoresist coating sprayed by the nozzle, and the middle point is located at a point between the center and the edge of the photoresist coating, wherein the photoresist thickness at the middle point is equal to half of the photoresist thickness at the center of the spray point.

[0027] In one embodiment of the present invention, in the volatilization suppression treatment step, the air pressure of the spraying environment is increased by adding an inert gas, the spraying environment is a process chamber, the air pressure in the process chamber is maintained at 1.5-5 atmospheres, and the inert gas includes nitrogen and the like.

[0028] In one embodiment of the present invention, in the volatilization suppression treatment step, the apparent viscosity of the photoresist is reduced by shear thinning control technology, which specifically includes the following steps: adding a diluent to the photoresist and stirring and mixing it thoroughly to obtain a diluted solution of the photoresist, and then applying 10kHz-100kHz high-frequency micro-vibration to the diluted solution through a piezoelectric oscillator to reduce the apparent viscosity of the high-viscosity photoresist by 20%-40%. By reducing the viscosity of the photoresist solution in this way, the volatile solvent in the photoresist solution can be reduced, thereby reducing the unevenness of the coating layer caused by solvent volatilization, thereby improving the coating uniformity of the high-viscosity photoresist, wherein the diluent includes acetone and propylene glycol methyl ether acetate.

[0029] In one embodiment of the present invention, in order to ensure that the photoresist is completely diluted, the photoresist and the diluent can be transferred to a beaker in sequence, and the photoresist and the diluent in the beaker are stirred by a magnetic stirrer of a magnetic stirrer to ensure that the liquid in the beaker is fully mixed. The speed range of the magnetic stirrer is 200rpm-500rpm, and the stirring time of the magnetic stirrer is 1min~3min. When the liquid in the beaker is not stratified and has no precipitate under static conditions, it can be said that the liquid is fully mixed.

[0030] In one embodiment of the present invention, the volume ratio of the photoresist, acetone and propylene glycol methyl ether acetate is 1:1-100:1-100, and the viscosity of the diluted photoresist solution is 5cp-800cp.

[0031] In one embodiment of the present invention, after the spraying process, the following operations are required: The gas in the spraying environment is recovered by exhausting it into the waste gas recovery system through a vacuum pump to prevent the waste gas from spreading outside the process chamber and causing pollution; The volatile solvents in the spraying environment are reused through condensation recovery and re-extraction process to improve the utilization rate of volatile solvents; Filter the remaining photoresist solution to remove large particles, then dissolve and use it to improve the utilization rate of the photoresist; Restore the air pressure of the spraying environment to standard atmospheric pressure, and dry the surface of the photoresist on the substrate by heating. For example, raise the temperature of the jig for positioning the substrate to 80 °C, and then remove the substrate from the jig.

[0032] In one embodiment of the present invention, transfer the substrate after spraying to a drying device, and heat the sprayed substrate by means of hot air or infrared irradiation to dry and volatilize the solvent on the substrate, cure the photoresist on the substrate surface, and continue to cure the photoresist until it meets the requirements of the exposure process. The baking temperature range is 90 °C - 110 °C, and the baking time range is 3 min - 5 min.

[0033] In one embodiment of the present invention, in the spraying process, an inert gas is used as a carrier of the photoresist and sprayed on the substrate. Specifically, first connect the centrifuged photoresist solution to the glue pump pipeline of the coater, then rinse the relevant pipelines inside the coater, turn on the nitrogen and air compressors, where nitrogen is used as the carrier gas during the coating process. After starting the operation program of the coater, ultrasonic atomize the centrifuged photoresist solution at the nozzle to form small molecular particles. The nitrogen will carry the photoresist atomized particles during the flow to form an aerosol, and finally it can be evenly sprayed on the substrate.

[0034] In one embodiment of the present invention, in order to improve production efficiency, a method of synchronous coating with multiple nozzles is adopted. Among them, for conventional small-area coating less than 10 cm 2 a conical coating head is used, and a fan-shaped coating head is mostly used for large-area coating.

[0035] In one embodiment of the present invention, in the pre-spraying step, measure the thickness of the photoresist on the substrate after coating multiple times at a certain distance from the center of the substrate to the edge of the substrate.

[0036] The advantages of the photoresist coating method described in the present invention are: Combined with the thickness change of the photoresist from the center to the edge of the substrate, optimize the spacing between adjacent spraying points, improve the distribution of the overlapping part of the photoresist between adjacent spraying points, make the total thickness of the photoresist between adjacent spraying points approach the thickness of the photoresist at the center of the spraying point, improve the overall uniformity of the coated layer on the substrate, and also reduce the volatilization of volatile solvents by means of dilution, pressurization, etc., reduce the problem of uneven coating layer thickness caused by solvent volatilization, and effectively improve the problem of uneven photoresist thickness at the edge of the irregular substrate. Example

[0037] Refer to Figure 2 and Figure 3As shown, a coating jig is also provided, which positions and sprays the substrate. The substrate is a square substrate. The coating jig includes, Multiple nozzles, the distance between adjacent nozzles is equal to twice the distance from the center of the spraying point to the middle point. The thickness of the photoresist at the middle point is half of the thickness of the photoresist at the center of the spraying point, and each nozzle is respectively aligned with one spraying point.

[0038] For the coating jig described in this embodiment, by optimizing the distance between adjacent nozzles, the distribution of the photoresist between adjacent nozzles is improved. For example, if the thickness of the photoresist at the center of the spraying point of the nozzle is 10 microns, and the thickness of the photoresist at an intermediate point between the center and the edge of the spraying point of the nozzle is 5 microns, then assuming the distance between the intermediate point and the center of the spraying point is 2 cm, the distance between adjacent nozzles is set to 4 cm. This makes the total thickness of the photoresist coverage superposition between the spraying points of adjacent nozzles approach the thickness of the photoresist at the center of the spraying point of the nozzle, thereby greatly improving the uniformity of the photoresist coating on the substrate.

[0039] In an embodiment of the present invention, it includes two nozzles, and the substrate is sprayed at multiple points by the synchronous reciprocating movement of the two nozzles, greatly improving the spraying efficiency.

[0040] Referring to Figure 3 As shown, in an embodiment of the present invention, the coating jig further includes, A base 11; Multiple carriers 111, the multiple carriers 111 are arranged on the base 11, facilitating the transfer of multiple carriers 111 at one time through the base 11. One carrier 111 is used to carry one substrate.

[0041] Referring to Figure 3 As shown, in an embodiment of the present invention, a gap 113 is provided between adjacent carriers 111. The gap 113 can reduce the problem of mutual interference between adjacent substrates during spraying, prevent the edge glue surfaces of adjacent substrates from sticking to each other, improve the uniformity of the photoresist at the edges of the substrates, and also facilitate the removal of the substrates by tools.

[0042] In an embodiment of the present invention, the size of the carrier 111 is smaller than the size of the substrate. After the substrate is placed above the carrier 111, the edge of the substrate is far from the edge of the carrier 111, which can avoid the glue surface at the edge of the substrate from sticking to the edge of the carrier 111 and causing the glue film to fall off when removing the substrate.

[0043] Referring to Figure 3 and Figure 5As shown, it further includes straight positioning blocks 13. A plurality of the straight positioning blocks 13 are symmetrically arranged at the opposite ends of the bearing platform 11, and the straight positioning blocks 13 are located between adjacent substrates. At both ends of each straight positioning block 13, there are perpendicular first abutting surfaces 1313 and second abutting surfaces 1321. The first abutting surface 1313 and the second abutting surface 1321 enclose a right-angled recess. The first abutting surface 1313 and the second abutting surface 1321 at one end of the straight positioning block 13 enclose a right-angled recess 133. Similarly, the first abutting surface 1313 and the second abutting surface 1321 at the other end of the straight positioning block 13 enclose a right-angled recess 134. Among them, the first abutting surface 1313 and the second abutting surface 1321 of the right-angled recess 133 respectively abut against two right-angled side edges of a substrate, and the first abutting surface 1313 and the second abutting surface 1321 of the other right-angled recess 134 respectively abut against two right-angled side edges of another substrate. The straight positioning blocks 13 are used to quickly position the substrates on the carrier platform 111 to ensure that the centers of the substrates coincide with the center of the carrier platform 111. By providing two right-angled recesses 133 / 134 on the straight positioning blocks 13, the two right-angled recesses 133 / 134 can simultaneously position the two right-angled side edges at the same end of the two substrates, and the two straight positioning blocks 13 arranged oppositely are used to position the two ends of the two adjacent substrates, improving the positioning efficiency.

[0044] In an embodiment of the present invention, a heating and temperature control device is provided inside the carrier platform 111, which can heat the surface of the carrier platform 111, and then cure the photoresist on the surface of the substrate. The temperature control range is 15 - 100 °C.

[0045] Refer to Figure 3 As shown, in an embodiment of the present invention, at least two handles 116 are provided on the side of the bearing platform 11. The handles 116 on the opposite sides are parallel to each other, which is convenient for transferring the bearing platform 11.

[0046] Refer to Figure 2 As shown, in an embodiment of the present invention, at least four support feet 123 are also arranged in an array at the bottom of the base 12. The support feet 123 are used to improve the stability of the base 12.

[0047] Refer to Figure 2 As shown, in an embodiment of the present invention, there are two carrier platforms 111 and two straight positioning blocks 13 on the bearing platform 11. The sides of the two carrier platforms 111 are parallel, and the two straight positioning blocks 13 can simultaneously position the two ends of the two substrates.

[0048] In an embodiment of the present invention, the width of the gap 113 is 8 - 10 mm.

[0049] Refer toFigure 5 As shown, in an embodiment of the present invention, a protruding member 1311 is provided on the top of the positioning block 13, and the protruding member 1311 serves to facilitate the insertion and removal of the straight positioning block 13.

[0050] Referring to Figure 3 As shown, in an embodiment of the present invention, the two right-angled sides of the carrier table 111 are respectively parallel to the first abutting surface 1313 and the second abutting surface 1321. Specifically, when there are two carrier tables 111 and two straight positioning blocks 13 on the bearing platform 11, the long sides of the carrier table 111 are parallel to the two second abutting surfaces 1321 on the same side, but do not touch; the two short sides of the carrier table 111 are parallel to the two first abutting surfaces 1313, but do not touch; when the two vertical sides of the substrate abut against the first abutting surface 1313 and the second abutting surface 1321, it can not only ensure that the center of the substrate coincides with the center of the carrier table 111, but also ensure that the edge of the substrate is misaligned with the edge of the carrier table 111; the other substrate and the carrier table 111 are arranged in the same way.

[0051] Referring to Figure 3 As shown, in an embodiment of the present invention, in order to accurately install the straight positioning block 13, mounting grooves 115 are provided on both sides of the bearing platform 11. The mounting grooves 115 are in imitation matching with the straight positioning block 13, and the straight positioning block 13 is arranged in the mounting grooves 115 and protrudes above the mounting grooves 115.

[0052] Referring to Figure 5 As shown, in an embodiment of the present invention, a ball plunger 1312 is provided on the side surface of the straight positioning block 13. The ball plunger 1312 abuts against the side wall of the mounting groove 115. The ball plunger 1312 can be telescopic and rolling, which is used to reduce the friction between the straight positioning block 13 and the side wall of the mounting groove 115 and improve the installation and disassembly efficiency of the straight positioning block 13.

[0053] In an embodiment of the present invention, after the center of the carrier table 111 is aligned with the center of the substrate, the straight positioning block 13 is removed from the mounting groove 115 of the bearing platform 11 to avoid the influence of the presence of the straight positioning block 13 on the coating effect of the substrate edge during coating.

[0054] In an embodiment of the present invention, ball plungers 1312 are provided on both sides of the straight positioning block 13 to further reduce the friction between both sides of the straight positioning block 13 and the mounting groove 115.

[0055] Referring to Figure 4As shown, in an embodiment of the present invention, it further includes a base 12 provided with a plurality of first pins 121. The bearing platform 11 is provided with first positioning holes, and the carrier stage 111 is provided with second positioning holes 112. The first positioning holes and the second positioning holes 112 are coaxially arranged so that the first pins 121 sequentially pass through the first positioning holes of the bearing platform 11 and pass out of the second positioning holes 112 of the carrier stage 111 to support the substrate. The first pins 121 are used to position the carrier stage 111 and the bearing platform 11. The top of the first pins 121 can also lift the substrate on the carrier stage 111, facilitating the removal of the substrate that has completed spraying.

[0056] In an embodiment of the present invention, the base 12 is provided with 8 first pins 121, the bearing platform 11 is provided with 8 first positioning holes, and each carrier stage 111 is provided with 4 second positioning holes 112.

[0057] Refer to Figure 4 As shown, in an embodiment of the present invention, the base 12 is further provided with a plurality of second pins 122 parallel to the first pins 121. In the vertical direction, the second pins 122 are higher than the first pins 121. The bearing platform 11 is provided with a plurality of third positioning holes 114. The plurality of third positioning holes 114 are located on both sides of the substrate, and the second pins 122 pass out of the third positioning holes 114. Since the carrier stage 111 on the bearing platform 11 will cover the first positioning holes, the operator cannot ensure that all the first pins 121 accurately pass through the first positioning holes. If only some of the first pins 121 pass through the first positioning holes, the bearing platform 11 will tilt during the descending process, causing the substrate to shift. Therefore, the second pins 122 are used to pass through the third positioning holes 114 first to position the bearing platform 11, ensuring that the first pins 121 can align with and pass through the first positioning holes and the second positioning holes 112, and ensuring the smooth descent of the bearing platform 11.

[0058] Refer to Figure 3 As shown, in an embodiment of the present invention, at least two second pins 122 are provided on each side of the bearing platform 11, and at least two third positioning holes 114 are provided on each side of the bearing platform 11.

[0059] In an embodiment of the present invention, the height of the straight positioning block 13 is 12 - 15 mm.

[0060] In an embodiment of the present invention, the length of the carrier stage 111 is 209 mm and the width is 104 mm.

[0061] In an embodiment of the present invention, the height of the bearing platform 11 is 25 mm.

[0062] In one embodiment of the present invention, the height of the first pin 121 is 25 - 35 mm, and the height of the second pin 122 is 35 - 45 mm.

[0063] In one embodiment of the present invention, the height of the carrier stage 111 is 5 - 8 mm.

[0064] In one embodiment of the present invention, the length of the substrate is 210 mm and the width is 105 mm.

[0065] Referring Figure 5 As shown, in one embodiment of the present invention, the straight positioning block 13 is composed of a vertical first square body 131 and a second square body 132. Among them, a second square body 132 is convexly provided on the side surface of the first square body 131. Two 90° angles of the first square body 131 and the second square body 132 form right-angle recesses 133 and 134, and the second square body 132 is located between adjacent carrier stages 111.

[0066] In one embodiment of the present invention, the depth of the mounting groove 115 is 5 - 8 mm.

[0067] In one embodiment of the present invention, the coating fixture is arranged on an automated transportation device, which facilitates the automated transportation of the coating fixture and the substrate, and improves production efficiency.

[0068] The working principle of the coating fixture of the present invention is: First, place the substrate on the carrier stage 111, then place the carrier stage 111 on the bearing platform 11. Transfer the bearing platform 11 to the base 12 through the handle 116. After ensuring the precise alignment of the second pin 122 and the third positioning hole 114, lower the bearing platform 11. The second pin 122 first passes through the third positioning hole 114. As the carrier stage 111 continues to descend, the first pin 121 sequentially passes through the first positioning hole and the second positioning hole 112, and finally jacks up the substrate on the carrier stage 111 until the bearing platform 11 completely descends onto the base 12. Finally, after adjusting the center of the substrate to align with the center of the carrier stage 111, remove the straight positioning block 13 and start coating the substrate.

[0069] Obviously, the above embodiments are merely examples for clear illustration and are not limitations on the implementation manners. For those of ordinary skill in the art, other different forms of changes or variations can be made based on the above description. It is not necessary and impossible to list all the implementation manners here. And the obvious changes or variations derived therefrom are still within the protection scope of the present invention.

Claims

1. A photoresist coating method, characterized in that: The steps include: Pre-spraying: The nozzle pre-sprays the substrate to obtain the photoresist thickness at the center and edge of the spraying point on the substrate; Volatilization suppression treatment: diluting the photoresist to obtain a diluted photoresist solution, applying high-frequency micro-vibration to the diluted solution to obtain a diluted solution with reduced apparent viscosity; Setting the spray point spacing: The distance between adjacent spray points on the substrate is set to be equal to twice the distance from the center of the spray point to the middle point, where the middle point is between the center of the spray point and the edge of the spray point, and the photoresist thickness of the middle point is half of the photoresist thickness at the center of the spray point; Spraying treatment: The air pressure of the spraying environment is increased, and the diluted solution with reduced apparent viscosity is sprayed on multiple spraying points of the substrate using the above-mentioned nozzle to complete the spraying.

2. A photoresist coating method according to claim 1, characterized in that: In the volatilization suppression process step, the gas pressure of the spraying environment is increased by adding an inert gas; in the spraying process step, the inert gas is sprayed onto the substrate as a carrier of the photoresist.

3. A photoresist coating method according to claim 1, characterized in that: In the volatilization suppression treatment step, the apparent viscosity of the photoresist is reduced by shear thinning control technology, which specifically includes the following steps: adding a diluent to the photoresist and mixing it thoroughly to obtain a diluted solution of the photoresist, wherein the diluent includes acetone and propylene glycol methyl ether acetate.

4. A photoresist coating method according to claim 3, characterized in that: The volume ratio of photoresist, acetone and propylene glycol methyl ether acetate is 1:1-100:1-100, and the viscosity of the diluted photoresist solution is 5cp-800cp.

5. A photoresist coating method according to claim 1, characterized in that: After spraying, the following operations are required: Recover the gas in the spraying environment by discharging it into the exhaust gas recovery system through a vacuum pump; The volatile solvents in the spraying environment are reused through condensation recovery and re-extraction process; Filter the remaining photoresist solution using a filter to remove large particles before dissolving and using; The air pressure of the spraying environment is restored to the standard atmospheric pressure, and the photoresist surface on the substrate is dried by increasing the temperature; The sprayed substrate is heated by hot air or infrared irradiation to evaporate the solvent on the substrate.

6. A coating jig for positioning the substrate according to any one of claims 1 to 5, characterized in that: include, Multiple nozzles, the spacing between adjacent nozzles is equal to twice the distance from the center of the spraying point to the middle point, the photoresist thickness at the middle point is equal to half the photoresist thickness at the center of the spraying point, and each nozzle is respectively aligned with one of the spraying points.

7. A coating jig according to claim 6, characterized in that: Also includes, platform; A plurality of carriers, the plurality of carriers are arranged on the support platform for carrying the substrate, a gap is provided between adjacent carriers, and the size of the carriers is smaller than the size of the substrate; A straight positioning block, a plurality of the straight positioning blocks are symmetrically arranged at both ends of the support platform, and the straight positioning blocks are located between adjacent substrates, and both ends of each of the straight positioning blocks are provided with a right-angle recess surrounded by a vertical first abutting surface and a second abutting surface, wherein the first abutting surface and the second abutting surface of one right-angle recess respectively abut against two right-angled sides of one substrate, and the first abutting surface and the second abutting surface of another right-angle recess respectively abut against two right-angled sides of another substrate, and the two right-angled sides of the support platform are parallel to the first abutting surface and the second abutting surface respectively.

8. A coating jig according to claim 7, characterized in that: The support platform is provided with a mounting groove matching the straight positioning block in shape, the straight positioning block is arranged in the mounting groove, and the straight positioning block is provided with a ball plunger, and the ball plunger abuts against the side wall of the mounting groove.

9. A coating jig according to claim 7, characterized in that: It also includes a base with multiple first pins, the support platform is provided with a first positioning hole, the carrier is provided with a second positioning hole, the first positioning hole and the second positioning hole are coaxially arranged, the first pin passes through the first positioning hole and the second positioning hole in sequence to support the substrate.

10. A coating jig according to claim 9, characterized in that: The base is also provided with a plurality of second pins parallel to the first pins, the length of the second pins is greater than the length of the first pins, the support platform is provided with a plurality of third positioning holes, and the plurality of third positioning holes are located on both sides of the substrate, and the second pins pass through the third positioning holes.

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