Preparation process of double-sided array pattern coated optical glass substrate

Abstract

The invention discloses a preparation process of a double-sided array pattern coated optical glass substrate. During exposure, double-sided low-reflection glass is used as a base plate of the lower layer of the thick glass substrate, so that reflected light is prevented from interfering with an exposure pattern form, and the pattern form is more accurate; according to the method, the sound wave degumming means is adopted for degumming, and ultrasonic cleaning and degumming by soaking with the degumming liquid are combined, so that the degumming effect is better, the degumming time is shortened, and the pattern morphology is better; the photoresist spin-coating process is combined with fixture gluing, center positioning of the square substrate is facilitated, it can be guaranteed that the center of the substrate coincides with the center of the platform under the condition that the substrate is provided with or not provided with a light-transmitting film layer, product damage caused by uneven stress of the substrate in the horizontal direction is prevented, uniformity of the photoresist thickness is guaranteed, and the yield of the product is improved. And the use amount of the photoresist can be reduced.

Description

Technical Field

[0001] The invention relates to the field of optical glass substrate preparation, and in particular to a preparation process of a double-sided array pattern coated optical glass substrate. Background Art

[0002] During the preparation process of the original pattern coated optical glass substrate, the product is usually placed directly on the fixture for exposure after the coating and pre-baking are completed in the exposure stage. Ideally, the light emitted by the light source passes through the mask plate to make the light incident vertically on the substrate surface. When incident at a vertical angle, the light will not be deflected when passing through the substrate, and will not affect the light reaction boundary of the upper surface photoresist after reaching the bottom surface and reflecting. After development, the image analysis should be observed to be a smooth and clear pattern outline; under realistic conditions, because the light will be incident on the upper surface of the substrate at a certain angle (the incident angle is not 0) after passing through the photoresist, and then reflected on the bottom surface of the substrate, the photoresist attached to the upper surface is "secondarily exposed". The thicker the glass, the longer the path of the reflected light, the greater the corresponding horizontal distance, and the greater the range affected by the reflection. Therefore, after the thick substrate is developed, the boundary of the small pattern with dense pores is blurred and rough, which affects the difficulty of implementing the subsequent process and the pattern size of the final product. Summary of the invention

[0003] In order to solve the above technical problems, the present invention designs a preparation process for a double-sided array pattern-coated optical glass substrate.

[0004] The present invention adopts the following technical solution: A process for preparing a double-sided array pattern coated optical glass substrate, the steps of which are: S1. Cleaning: Clean the surface of the substrate to remove particles and chemical residues on the surface of the substrate, and spin dry the cleaned substrate; S2, spin coating photoresist: place the substrate at the center of the adsorption platform with a clamp, first drip 5ml of negative photoresist at the center of the substrate through the dispensing module of the glue coating machine, at this stage, continuously inject the trickle state of negative photoresist at a speed of 3.0ml / min through the Teflon needle, rotate the substrate at an initial low speed of 800rpm, maintain for 3s, so that the photoresist is evenly spread into a circle, and then accelerate with an angular acceleration of 340.17rad / s2, the acceleration time is 0.4s, and when the speed is increased to 2100rpm, maintain this speed for 5s, and then reduce the speed with an angular acceleration of 44.07rad / s2, the deceleration time is 3.8s, reduce to 500rpm, the cumulative spin coating time is 12.2s, and a layer of negative photoresist film is formed, and then the program is completed, the rotation is stopped and reset; S3, pre-baking: use a hot plate to bake the substrate at a temperature of 125°C for 150 seconds; S4, exposure: Place a double-sided low-reflection glass under the upper substrate of the fixture, and perform photolithography through a mask corresponding to the photoresist placed above the substrate; the exposure energy is 9mW / cm in the 365nm band 2， The exposure time is 4.5s, and the exposure method is contact exposure. The setting of double-sided low-reflection glass reduces the light passing through the substrate product to reach the fixture surface during exposure, and is reflected by the fixture to the photoresist that does not need to be exposed, causing misexposure, which in turn affects the pattern accuracy and causes residual glue, size and other defects. For patterns with a line width of less than 20um, the use of low-reflection glass has a better effect.

[0005] S5, post-baking: use a hot plate to bake at a temperature of 122°C for 400 seconds to reduce the standing wave effect, while stimulating and enhancing the acid generated by the photoacid agent in the photoresist to react with the protective group of the photoresist, thereby achieving the purpose of destroying the group and making the photoresist soluble in the developer; S6, development: the development is carried out by spin-on immersion development, and the development time is 600s; the purpose is to remove the part that has not undergone photochemical reaction during the exposure process, so that the substrate can fully show the pattern on the mask; S7, hard film: bake the substrate on a hot plate at 150°C for 5 minutes to completely evaporate the solvent in the photoresist, improve the photoresist's ability to resist ion cleaning during coating to maintain the pattern, and further reduce the standing wave effect; S8, coating: deposit a low-reflection and low-transmittance film layer on the surface of the product by evaporation or sputtering coating; S9, cleaning: clean the surface of the coated substrate and dry the cleaned substrate; the cleaning is carried out through 1 alkaline detergent tank (40KHz, 1.8A current intensity, cleaning 240s), 8 ultrasonic water washing tanks (80KHz, 1.7A current intensity, cleaning 240s) and two drying tanks (temperature set to 85℃, time is 240s).

[0006] S10, performing S3-S9 steps on the other side of the substrate; S11, ultrasonic degumming: placing the substrate after step S10 into an ultrasonic washing tank, adding a degumming liquid, and performing ultrasonic degumming on the coated product for 6 hours; based on the action principle of ultrasonic cavitation effect in liquid, ultrasonic degumming can make the surface of the adhesive layer receive a large amount of impact while accelerating the reaction speed between the degumming liquid and the adhesive layer, and the degumming effect is better; S12, peeling: placing the debonded product on a rotating peeling platform to peel off the remaining residual glue and residual film.

[0007] Preferably, the double-sided low-reflection glass is made of glass with a thickness of 0.245 mm, and low-reflection film layers are processed on both sides of the glass. The side in contact with the surface of the fixture is superimposed with UV absorbing ink to absorb ultraviolet light, and is processed by coating to avoid warping of the product during processing.

[0008] Preferably, the rotating stripping platform is set to rotate at 1000 rpm and the stripping time is 130 seconds. The debonding liquid impacts the substrate surface where the film layer has been peeled off in the form of a water flow with a certain pressure, and rotates to completely strip off the remaining residual glue and residual film.

[0009] Preferably, the set temperature of the ultrasonic washing tank in step S11 is 85° C. and the frequency is 2.5 KHz.

[0010] Preferably, the fixture includes a fixture seat, which is recessed inwardly with a substrate mounting groove, the shape and size of the substrate mounting groove match the shape and size of the substrate to be processed, a circle of positioning marking lines matching the adsorption platform is provided in the substrate mounting groove on the fixture seat, a plurality of positioning holes tangent to the positioning marking lines are evenly provided along the outer edge of the positioning marking lines on the fixture seat, the positioning holes are fixedly connected with positioning columns protruding downward, and a plurality of vacuum adsorption channels are provided in the positioning marking lines on the fixture seat corresponding to the vacuum port of the adsorption platform.

[0011] Preferably, the positioning column is cylindrical.

[0012] Preferably, the cross-section of the substrate seating groove is square.

[0013] Preferably, film taking openings are provided on both sides of the substrate placement groove on the fixture seat.

[0014] Preferably, arc openings are respectively provided at the four corners of the substrate placement groove on the fixture seat.

[0015] The substrate is placed in the middle of a special circular fixture. The top of the middle of the fixture is designed to be concave, with a depth of 2mm lower than the substrate, and the four corners are designed to be R angles. A cylindrical positioning column is designed on the back of the fixture, which can be aligned with the center of the vacuum adsorption platform. This design has two advantages: ① Since the product is plated with a black film, the first side is subjected to the yellow light process and coating, and the product is not transparent when the second side is made, making it difficult to align. Therefore, a cylindrical positioning column is designed on the back of the fixture platform for locking and positioning. It is easy to operate and align during operation, and can share an adsorption platform with other circular substrate products. When making circular products, you only need to remove the fixture; ② The main purpose of the fixture is to improve the uniformity of the glue thickness and reduce the amount of photoresist used.

[0016] The beneficial effects of the present invention are as follows: (1) during exposure, the present invention uses double-sided low-reflection glass as a pad for the lower layer of the thick glass substrate to prevent reflected light from interfering with the exposure pattern morphology, thereby making the pattern morphology more precise; (2) the present invention uses acoustic wave degumming as a means of degumming, combining ultrasonic cleaning with degumming by immersion in a degumming liquid, thereby achieving better degumming effect, shortening degumming time, and improving pattern morphology; (3) the present invention combines the spin coating of photoresist with the glue coating of the fixture, thereby facilitating the center positioning of the square substrate. Whether there is a light-transmitting film layer on the substrate or not, the center of the substrate can be ensured to coincide with the center of the platform, thereby preventing product damage caused by uneven force on the substrate in the horizontal direction, and ensuring uniform glue thickness while reducing the amount of photoresist used. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 This is a 50x photo schematic diagram of the product prepared by the original process after development under a laser microscope; Figure 2 This is a photo schematic diagram of the product prepared by the original process after development under a laser microscope at 150 times magnification; Figure 3 This is a 50x laser microscope photo schematic of the product prepared by the original process after degumming; Figure 4 This is a photo schematic diagram of the product prepared by the original process after degumming under a laser microscope at 150 times magnification; Figure 5 This is a schematic diagram of a 50x laser microscope photo of the product prepared by the process of the present invention after development; Figure 6 This is a schematic diagram of a laser microscope 150 times magnified photograph of the product prepared by the process of the present invention after development; Figure 7 This is a schematic diagram of a laser microscope at 50 times magnification after degumming of the product prepared by the process of the present invention; Figure 8 This is a schematic diagram of a laser microscope 150 times magnified photograph of the product prepared by the process of the present invention after degumming; Fig. 9 This is a schematic diagram of a structure without low-reflection glass exposure; Fig.10 This is a schematic diagram of a structure in which reflective glass exposure is added to the present invention; Fig.11 It is the reflection curve of each reflection surface when the reflection glass is added to expose the present invention; Fig.12 The present invention adds a reflective glass to absorb the ink penetration curve when exposed; Fig.13 It is a structural diagram of the front side of the fixture; Fig.14 It is a structural diagram of the back of the fixture; Fig.15This is a schematic diagram of a structure after the substrate is spin-coated with photoresist using a fixture; DETAILED DESCRIPTION

[0018] The technical solution of the present invention is further described in detail below through specific embodiments and in conjunction with the accompanying drawings: Embodiment: A process for preparing a double-sided array pattern coated optical glass substrate, the steps of which are: S1. Cleaning: Clean the surface of the substrate to remove particles and chemical residues on the surface of the substrate, and spin dry the cleaned substrate; S2, spin coating photoresist: place the substrate at the center of the adsorption platform with a clamp, first drip 5ml of negative photoresist at the center of the substrate through the dispensing module of the glue coating machine, at this stage, continuously inject the trickle state of negative photoresist at a speed of 3.0ml / min through the Teflon needle, rotate the substrate at an initial low speed of 800rpm, maintain for 3s, so that the photoresist is evenly spread into a circle, and then accelerate with an angular acceleration of 340.17rad / s2, the acceleration time is 0.4s, and when the speed is increased to 2100rpm, maintain this speed for 5s, and then reduce the speed with an angular acceleration of 44.07rad / s2, the deceleration time is 3.8s, reduce to 500rpm, the cumulative spin coating time is 12.2s, and a layer of negative photoresist film is formed, and then the program is completed, the rotation is stopped and reset; S3, pre-baking: use a hot plate to bake the substrate at a temperature of 125°C for 150 seconds; S4, exposure: Place a double-sided low-reflection glass under the upper substrate of the fixture, and perform photolithography through a mask corresponding to the photoresist placed above the substrate; the exposure energy is 9mW / cm in the 365nm band 2， The exposure time is 4.5s, and the exposure method is contact exposure. The setting of double-sided low-reflection glass reduces the light passing through the substrate product to reach the fixture surface during exposure, and is reflected by the fixture to the photoresist that does not need to be exposed, causing misexposure, which in turn affects the pattern accuracy and causes residual glue, size and other defects. For patterns with a line width of less than 20um, the use of low-reflection glass has a better effect.

[0019] S5, post-baking: use a hot plate to bake at a temperature of 122°C for 400 seconds to reduce the standing wave effect, while stimulating and enhancing the acid generated by the photoacid agent in the photoresist to react with the protective group of the photoresist, thereby achieving the purpose of destroying the group and making the photoresist soluble in the developer; S6, development: the development is carried out by spin-on immersion development, and the development time is 600s; the purpose is to remove the part that has not undergone photochemical reaction during the exposure process, so that the substrate can fully show the pattern on the mask; S7, hard film: bake the substrate on a hot plate at 150°C for 5 minutes to completely evaporate the solvent in the photoresist, improve the photoresist's ability to resist ion cleaning during coating to maintain the pattern, and further reduce the standing wave effect; S8, coating: deposit a low-reflection and low-transmittance film layer on the surface of the product by evaporation or sputtering coating; S9, cleaning: clean the surface of the coated substrate and dry the cleaned substrate; the cleaning is carried out through 1 alkaline detergent tank (40KHz, 1.8A current intensity, cleaning 240s), 8 ultrasonic water washing tanks (80KHz, 1.7A current intensity, cleaning 240s) and two drying tanks (temperature set to 85℃, time is 240s).

[0020] S10, performing S3-S9 steps on the other side of the substrate; S11, ultrasonic degumming: placing the substrate after step S10 into an ultrasonic washing tank, adding a degumming liquid, and performing ultrasonic degumming on the coated product for 6 hours; based on the action principle of ultrasonic cavitation effect in liquid, ultrasonic degumming can make the surface of the adhesive layer receive a large amount of impact while accelerating the reaction speed between the degumming liquid and the adhesive layer, and the degumming effect is better; S12, peeling: placing the debonded product on a rotating peeling platform to peel off the remaining residual glue and residual film.

[0021] Double-sided low-reflection glass uses 0.245mm thick glass, and low-reflection film layers are processed on both sides of the glass. The side in contact with the fixture surface is superimposed with UV absorption ink to absorb ultraviolet light, and is processed by coating to avoid warping of the product during processing.

[0022] The photosensitive band of photoresist is the ultraviolet band, so the reflection from the bottom of the product and the contact surface of the product is very important, especially for products with high line width requirements, such as Fig. 9 As shown in FIG. 1 , it is a schematic diagram of a structure of the original exposure without low-reflection glass, such as Fig.10As shown, it is a schematic diagram of a structure of the present invention with reflective glass exposure; the fixture surface of the lithography machine has a maximum reflectivity of 4.5% in the 350-500nm band, a minimum reflectivity of 1.88%, and an average reflectivity of 2.17%; the low-reflection glass S1 surface (the surface in contact with the product) has a maximum reflectivity of 0.43% in the 350-500nm band, a minimum reflectivity of 0.03%, and an average reflectivity of 0.10%; the S2 surface (the fixture contact surface) has a maximum reflectivity of 0.31% in the 350-500nm band, a minimum reflectivity of 0.03%, and an average reflectivity of 0.16%. After using the low-reflection glass, the reflectivity is greatly reduced, which greatly reduces the photoresist exposure error caused by the high reflectivity of the original fixture. In addition, the superposition of absorption ink can increase the absorption of the ultraviolet light band, further reducing the diffuse reflection of ultraviolet light between the product and the low-reflection glass and the fixture. The transmission curve is shown in FIG. Fig.11 and Fig.12 shown.

[0023] The rotation speed of the rotary stripping platform is set to 1000 rpm, and the stripping time is 130 seconds. The debonding liquid impacts the substrate surface where the film layer has been peeled off in the form of a water flow with a certain pressure, and rotates to completely strip off the remaining residual glue and residual film.

[0024] In step S11, the set temperature of the ultrasonic cleaning tank is 85° C. and the frequency is 2.5 KHz.

[0025] like Fig.13 and Fig.14 As shown, the fixture includes a fixture seat, and a substrate placement groove is provided on the fixture seat inwardly concave, and the shape and size of the substrate placement groove match the shape and size of the substrate to be processed. A circle of positioning marking lines matching the adsorption platform is provided in the substrate placement groove on the fixture seat, and multiple positioning holes tangent to the positioning marking lines are evenly provided along the positioning marking lines on the fixture seat. The positioning holes are fixedly connected with positioning columns protruding downward, and multiple vacuum adsorption channels are provided in the positioning marking lines on the fixture seat corresponding to the vacuum port of the adsorption platform. The positioning column is cylindrical. The cross-section of the substrate placement groove is square. Film taking openings are provided on both sides of the substrate placement groove on the fixture seat. Arc openings are respectively provided at the four corners of the substrate placement groove on the fixture seat.

[0026] The substrate is placed in the middle of a special circular fixture. The top of the middle of the fixture is designed to be concave, with a depth of 2mm lower than the substrate, and the four corners are designed to be R angles. A cylindrical positioning column is designed on the back of the fixture, which can be aligned with the center of the vacuum adsorption platform. This design has two advantages: ① Since the product is plated with a black film, the first side is subjected to the yellow light process and coating, and the product is not transparent when the second side is made, making it difficult to align. Therefore, a cylindrical positioning column is designed on the back of the fixture platform for locking and positioning. It is easy to operate and align during operation, and can share an adsorption platform with other circular substrate products. When making circular products, you only need to remove the fixture; ② The main purpose of the fixture is to improve the uniformity of the glue thickness and reduce the amount of photoresist used.

[0027] like Fig.15 The figure shows a schematic diagram of a structure after the substrate is spin-coated with photoresist using a fixture. In the figure, each edge of the substrate is used as a measuring point to detect the thickness of the photoresist. The substrate after spin-coating the photoresist without using a fixture is used to measure the thickness of the photoresist at the same measuring point for comparison and reference. The test results are as follows: The data in the table show that without using the fixture, the uniformity of the glue thickness is within 2.35±1.3um, and the dispersion is 1.495um. After using the fixture, the uniformity of the glue thickness is within 2.35±0.1um, and the dispersion is 0.175um, and the uniformity is greatly improved.

[0028] like Figure 1-Figure 8 As shown, there are respectively schematic diagrams of laser microscope photos taken at 50 times and 150 times magnification after degumming of the products prepared by the original process and the process of the present invention, and schematic diagrams of laser microscope photos taken at 50 times and 150 times magnification after degumming of the products; by comparison, it can be seen that the pattern morphology of the products prepared by the process of the present invention is more precise and clear.

[0029] The above-described embodiment is only a preferred solution of the present invention and does not limit the present invention in any form. There are other variations and modifications without exceeding the technical solution described in the claims.

Claims

1. A process for preparing a double-sided array pattern coated optical glass substrate, characterized in that: The steps are: S1. Cleaning: Clean the surface of the substrate to remove particles and chemical residues on the surface of the substrate, and spin dry the cleaned substrate; S2, spin coating photoresist: place the substrate at the center of the adsorption platform with a clamp, first drip 5ml of negative photoresist at the center of the substrate through the dispensing module of the glue coating machine, at this stage, continuously inject the trickle state of negative photoresist at a speed of 3.0ml / min through the Teflon needle, rotate the substrate at an initial low speed of 800rpm, maintain for 3s, so that the photoresist is evenly spread into a circle, and then accelerate with an angular acceleration of 340.17rad / s2, the acceleration time is 0.4s, and when the speed is increased to 2100rpm, maintain this speed for 5s, and then reduce the speed with an angular acceleration of 44.07rad / s2, the deceleration time is 3.8s, reduce to 500rpm, the cumulative spin coating time is 12.2s, and a layer of negative photoresist film is formed, and then the program is completed, the rotation is stopped and reset; S3, pre-baking: use a hot plate to bake the substrate at a temperature of 125°C for 150 seconds to evaporate the organic solvent in the photoresist, solidify the glue on the surface of the substrate, and improve the adhesion between the photoresist and the substrate; S4, exposure: a piece of double-sided low-reflection glass is placed below the upper substrate of the fixture, and photolithography is performed through a mask plate corresponding to the photoresist placed above the substrate; S5, post-baking: use a hot plate for baking, the baking temperature is 122°C, and the time is 400s; S6, development: using a rotary immersion development method, the development time is 600s; S7, hard film: bake the substrate on a hot plate at 150°C for 5 minutes; S8, coating: deposit a low-reflection and low-transmittance film layer on the surface of the product by evaporation or sputtering coating; S9, cleaning: cleaning the surface of the substrate after coating, and drying the cleaned substrate; S10, performing S3-S9 steps on the other side of the substrate; S11, ultrasonic degumming: placing the substrate after step S10 into an ultrasonic cleaning tank, adding a degumming solution, and performing ultrasonic degumming on the coated product for 6 hours; S12, peeling: placing the debonded product on a rotating peeling platform to peel off the remaining residual glue and residual film.

2. The process for preparing a double-sided array pattern coated optical glass substrate according to claim 1, characterized in that: The double-sided low-reflection glass is made of glass with a thickness of 0.245 mm, and low-reflection film layers are processed on both sides of the glass, wherein the side in contact with the fixture surface is superimposed with UV absorbing ink and processed by coating.

3. The process for preparing a double-sided array pattern coated optical glass substrate according to claim 1, characterized in that: The rotating stripping platform was set at a rotation speed of 1000 rpm and a stripping time of 130 s.

4. The process for preparing a double-sided array pattern coated optical glass substrate according to claim 1, characterized in that: In step S11, the set temperature of the ultrasonic cleaning tank is 85° C. and the frequency is 2.5 KHz.

5. The process for preparing a double-sided array pattern coated optical glass substrate according to claim 1, characterized in that: The fixture includes a fixture seat, which is recessed inwardly with a substrate placement groove, the shape and size of the substrate placement groove match the shape and size of the substrate to be processed, a circle of positioning marking lines matching the adsorption platform is arranged in the substrate placement groove on the fixture seat, a plurality of positioning holes tangent to the positioning marking lines are evenly arranged along the outer edge of the positioning marking lines on the fixture seat, the positioning holes are fixedly connected with positioning columns protruding downward, and a plurality of vacuum adsorption channels are arranged in the positioning marking lines on the fixture seat corresponding to the vacuum port of the adsorption platform.

6. The process for preparing a double-sided array pattern coated optical glass substrate according to claim 5, characterized in that: The positioning column is cylindrical.

7. The process for preparing a double-sided array pattern coated optical glass substrate according to claim 5, characterized in that: The cross section of the substrate placement groove is square.

8. The process for preparing a double-sided array pattern coated optical glass substrate according to claim 5, characterized in that: The clamp seat has film taking openings on both sides of the substrate placement groove.

9. The process for preparing a double-sided array pattern coated optical glass substrate according to claim 5, characterized in that: The four corners of the substrate placement groove on the fixture seat are respectively provided with arc openings.

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