Manufacturing method of double-sided micro-lens structure

Abstract

The invention discloses a manufacturing method of a double-sided micro-lens structure. The manufacturing method comprises the following steps: providing a substrate; coating photoresist on the first surface and forming a first colloid through a photoetching process and a backflow process; performing pattern transfer etching to form a first micro lens; bonding the first surface on the slide glass by using a bonding material; forming a second micro lens on the second surface, and forcibly cooling the slide glass in the etching process; and releasing the bonding between the first surface and the slide glass to obtain the double-sided micro-lens structure. According to the invention, the first micro-lens on the first surface is compactly bonded with the carrier plate through the bonding material, and the purging cooling of the first surface is converted into the purging cooling of the carrier plate, so that the influence of the first micro-lens on the purging of the cooling gas can be avoided, the purging efficiency and uniformity of the cooling gas are improved, and the production efficiency is improved. Therefore, the problem of carbonization of partial photoresist colloid caused by out-of-control local temperature is avoided, the influence on the structure and appearance of the micro lens on the second surface is avoided, and the reject ratio during batch production is remarkably reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of semiconductor microlens manufacturing, and in particular to a method for manufacturing a double-sided microlens structure. Background Art

[0002] The microlens structure plays a role in light path shaping and is an important component of the optical device structure. With the demand for increased computing power and the demand for miniaturization of device structures, higher requirements are placed on the number of lenses and coupling efficiency.

[0003] In this context, researchers have developed a double-sided structural lens that not only saves device size and area, but also has a higher coupling effect.

[0004] During the research and development process, the inventors of the present invention found that in the semiconductor process manufacturing, the double-sided structure limits the implementation of the etching process, especially the double-sided convex lens structure has the greatest impact. This is because the back of the etching process needs to be attached to the carrier, and the wafer is cooled and dissipated by circulating coolant and cooling gas (generally helium). The cooling gas purges the wafer and plays a major role in heat dissipation. The presence of the convex lens structure causes the cooling gas to not purge the wafer evenly, resulting in excessively high wafer temperature. The high temperature causes carbonization of the surface pattern photoresist, which affects the structure and appearance of the product, and then leads to the production of defective products. Summary of the invention

[0005] In view of the shortcomings of the prior art, an object of the present invention is to provide a method for manufacturing a double-sided microlens structure.

[0006] In order to achieve the above-mentioned invention object, the technical solution adopted by the present invention includes: The present invention provides a method for manufacturing a double-sided microlens structure, which comprises: Providing a substrate having a first surface and a second surface disposed opposite to each other; The first surface is coated with photoresist and subjected to photolithography and reflow processes to form a first colloid; Performing pattern transfer etching on the first surface by using the first colloid to form a first microlens on the first surface; Bonding the first surface having the first microlens to a carrier wafer using a bonding material; The second surface is coated with photoresist and subjected to photolithography and reflow processes to form a second colloid; Performing pattern transfer etching on the second surface by using the second colloid to form a second microlens on the second surface, and applying forced cooling to the carrier during the etching process; The bonding between the first surface and the carrier is released to obtain a double-sided microlens structure.

[0007] Based on the above technical solution, compared with the prior art, the beneficial effects of the present invention at least include: The manufacturing method provided by the present invention utilizes the idea of ​​temporary bonding to form a dense bond between the first microlens on the first surface and the carrier through a bonding material, and converts the purging cooling of the first surface into the purging cooling of the carrier, so that the influence of the first microlens, especially the convex first microlens, on the purging of the cooling gas can be avoided, the efficiency and uniformity of the cooling gas purging can be improved, and the problem of partial carbonization of the photoresist colloid caused by local temperature runaway can be avoided, thereby avoiding the influence on the structure and appearance of the microlens on the second surface, and significantly reducing the defective rate during mass production.

[0008] The above description is only an overview of the technical solution of the present invention. In order to enable those skilled in the art to more clearly understand the technical means of the present application and implement them according to the contents of the specification, the following is a description of the preferred embodiments of the present invention in conjunction with detailed drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] Figure 1 is a schematic diagram of the bonding state of a manufacturing method provided by a typical embodiment of the present invention; Figure 2 It is a schematic diagram of a complete process of a manufacturing method provided by a typical embodiment of the present invention; Figure 3 It is a schematic structural diagram of a reflux device used in a manufacturing method provided by a typical embodiment of the present invention; Figure 4 It is a microphotograph of a microlens made by a manufacturing method provided in a ratio of the present invention; Figure 5 is a microphotograph of a microlens produced by a production method provided by another comparative example of the present invention; Figure 6 is a microphotograph of a microlens produced by a production method provided by a typical embodiment of the present invention; Figure 7 is a surface diagram of a microlens manufactured by a manufacturing method provided by another typical embodiment of the present invention; Figure 8 This is a surface diagram of a microlens manufactured by a manufacturing method provided by a typical embodiment of the present invention.

[0010] Explanation of the accompanying drawings: 1. Water bath; 2. Circulating fluid; 3. Support structure; 4. Lens structure; 5. Cover plate. DETAILED DESCRIPTION

[0011] Some prior arts mention methods for making double-sided microlenses, such as the Chinese invention patent with publication number CN112630873A, which proposes coating photoresist on both sides of a glass substrate; placing the glass substrate coated with photoresist on a photolithography platform; using a photolithography machine for exposure; performing a development operation after exposure; placing the developed glass substrate in a constant temperature box; S6, an overall preparation scheme for transferring the photoresist pattern to the glass substrate by a graphic transfer method, but the etching process cannot currently achieve simultaneous etching of both sides, and can only adopt a method of etching both sides back and forth, which, as shown in the background technology of the present invention, will cause heat dissipation problems, thereby leading to various disadvantages.

[0012] In view of the deficiencies in the prior art, the inventor of this case has proposed the technical solution of the present invention after long-term research and extensive practice. The technical solution, its implementation process and principle will be further explained as follows.

[0013] In the following description, many specific details are set forth to facilitate a full understanding of the present invention. However, the present invention may also be implemented in other ways different from those described herein. Therefore, the protection scope of the present invention is not limited to the specific embodiments disclosed below.

[0014] Moreover, relational terms such as “first” and “second” are merely used to distinguish one component or method step from another with the same name, but do not necessarily require or imply any such actual relationship or order between these components or method steps.

[0015] See also Figure 1 and Figure 2 As shown, an embodiment of the present invention provides a method for manufacturing a double-sided microlens structure, which includes the following steps: Providing a substrate having a first surface and a second surface disposed opposite to each other; The first surface is coated with photoresist and subjected to photolithography and reflow processes to form a first colloid; Performing pattern transfer etching on the first surface by using the first colloid to form a first microlens on the first surface; Bonding the first surface having the first microlens to a carrier wafer using a bonding material; The second surface is coated with photoresist and subjected to photolithography and reflow processes to form a second colloid; Performing pattern transfer etching on the second surface by using the second colloid to form a second microlens on the second surface, and applying forced cooling to the carrier during the etching process; The bonding between the first surface and the carrier is released to obtain a double-sided microlens structure.

[0016] Based on the above technical solution, the present invention combines the substrate and the carrier together through a bonding method, thereby providing good heat dissipation for the substrate, avoiding product defects caused by carbonization of the photoresist, and providing good protection for the first microlens on the first surface during the CMP / photolithography process.

[0017] The lens structure involved in the present invention is, for example, a double-sided convex lens / double-sided concave lens / one-side convex and one-side concave lens. The specific shape of the lens includes spherical / aspherical / cylindrical lens, and the substrate materials involved include Si / SiO2 / Ge / InP GaAs, etc., but are not limited to these.

[0018] The method of temporary bonding of the wafer adopted in the above technical solution not only plays the fixing and protection role played by traditional temporary bonding in the semiconductor field, but more importantly solves the heat dissipation problem. This problem has not been taken seriously in many precedents for the preparation of double-sided lenses, but is a special phenomenon noticed by the inventor of the present invention during the long-term production and research and development process, especially for some lens types with higher lens height and lower contact angle, this phenomenon becomes more and more obvious.

[0019] In the present invention, the bonding material between the carrier and the substrate not only plays the role of fixing and supporting / protecting the first surface, but also serves as a bridge for heat dissipation, which plays an important role in improving the product process. Regarding the most critical bonding process in the present invention, the present invention has also made certain improvements in heat dissipation performance. For example, in some embodiments, the bonding process specifically includes the steps of primary bonding, annealing treatment, and secondary bonding; the primary bonding is used to achieve the first combination of the first surface and the carrier, and the bonding pressure is removed during the annealing treatment and the temperature is used for treatment, and the bonding pressure continues to be applied during the secondary bonding.

[0020] In some embodiments, the temperature of the primary bonding and / or secondary bonding is 200-220° C., the time is 5-10 min, and the pressure is 2-6 kN; the temperature of the annealing treatment is 200-230 degrees, and the time is 10-20 min.

[0021] As a specific example, the products after sequential bonding can be annealed at a temperature of 200-230 degrees for 10-20 minutes. After annealing, secondary bonding can be performed. The bonding conditions may be slightly different from the primary bonding. This method can ensure that the structure of the intermediate bonding material is flat and smooth without voids, thereby improving its heat dissipation and flow conduction function.

[0022] In some embodiments, the bonding process may further include the following steps: The bonding material is coated on the first surface with the first microlens to form a bonding adhesive layer, and the bonding material layer is formed after the adhesive is baked. Then, the bonding material layer is attached to the surface of the carrier for pressure bonding.

[0023] In some embodiments, the thickness of the bonding glue layer is 1.1-1.3 times the height or depth of the first microlens.

[0024] As a typical example of the above implementation, the thickness of the bonding layer material is set according to the height of the first lens, generally 1.1-1.3 times of the first lens height, and then baked for 10-20 minutes at a temperature between 120-150°C. Finally, the substrate and the carrier are bonded by a bonding device at 200-220°C, a bonding pressure of 2-6kN, and a bonding time of 5-10 minutes to ensure good bonding strength. Second, for the selection of bonding materials, the debonding temperature must be above 250 degrees to prevent the carrier temperature from concentrating during the etching process and causing the bonding material to melt.

[0025] Regarding the specific processing of the first lens and the second lens, you can refer to many existing processing methods. Generally, the first / second lens is made by photolithography / etching process; photolithography includes steps such as coating / exposure / development / reflow. The etching process can use plasma dry etching (ICP), and select appropriate etching gas components and ratios according to different etching materials. For example, when quartz, silicon, and Ge are used as substrates, fluorine-based gases such as SF6 / CF4 / CHF3 / C3F8 can be used. When InP and GaAs are used as substrates, chlorine-based gases such as Cl2 / BCl3 can be used. At the same time, some O2 / H2 can be added to adjust the etching rate, and the etching is accurately transferred to the etching substrate according to the glue ball surface shape.

[0026] Of course, the specific photolithography and etching processes are not necessarily limited to the scope specifically exemplified in the present invention.

[0027] In addition, the present invention also makes certain improvements to the reflow process. The traditional thermal reflow method is to use a hot plate to heat the structure so that the photoresist flows and forms. In some embodiments, the reflow process is carried out in a steam condensation cycle, and the steam condensation cycle can specifically include the following process: The circulating liquid is heated to form vapor, and the lens structure to be processed by the reflow process is brought into contact with the vapor, so that the photoresist remaining after the photolithography process forms the first colloid or the second colloid under the action of its own surface tension.

[0028] In some embodiments, the circulating fluid includes ethanol and / or isopropanol diluted with water; the heating temperature of the steam condensation cycle is 80-100° C. and the time is 2-5 min.

[0029] See also Figure 3As shown, the preferred reflow method used in the embodiment of the present invention avoids the problem of uneven reflow surface of the hot plate, and can solve some special surface reflow methods, such as large diameter and low contact angle lenses. (For example, lenses with diameter > 1mm and contact angle < 10°) The reflux system is mainly composed of a water bath 1, a circulating liquid 2, a supporting structure 3, a lens structure 4, and a cover plate 5. The reflux system has a simple structure and is easy to operate. The cover plate structure design allows the solution to be condensed and reused. The circulating liquid 2 can be diluted alcohol / isopropanol or other solutions, the water bath 1 temperature is set to 80-100°C, the reflux time is set to 2-5min, and the lens structure 4 forms a colloid microlens morphology under the combined action of tension and molecular force after the solution is vaporized after being heated. This method has low setting temperature, high reflux efficiency, uniform morphology, regular lens morphology, and SPD <15nm (SPD represents profile deviation).

[0030] In some embodiments, the debonding temperature of the bonding material is above 250°C.

[0031] In some embodiments, the carrier is selected from a silicon wafer, and the thickness of the carrier is 5-10um greater than the designed thickness of the double-sided microlens structure. In some specific examples, a double-polished silicon wafer can be selected, and the thickness is 5-10um greater than the theoretical product thickness to compensate for the loss of vector height caused by over-etching during the etching process; in addition, the production of front and back mark marks can generally be completed by conventional double-sided photolithography etching process, and the double-sided mark points are used as subsequent single-sided lens lithography. In the field of semiconductor technology, conventional bonding carriers generally use lens quartz materials, and the preferred case of the present invention uses a carrier wafer silicon wafer as a bonding carrier in the bonding, which can not only ensure that the thermal expansion coefficient is consistent with the wafer, but also the thermal conductivity of glass quartz is very high, and the heat dissipation capacity is poor, which cannot meet the requirements of this process product, and can ensure that TTV is less than 10um after bonding (TTV represents the total thickness change, which is a parameter commonly used in wafer thickness measurement. It describes the maximum positive deviation and maximum negative deviation of each point on the wafer relative to the average thickness).

[0032] In some embodiments, the forced cooling includes cooling by circulating a coolant and simultaneously purging with a coolant gas.

[0033] In the final debonding process, the wafer can be heated above 250°C, the substrate and the carrier can be separated by thermal sliding, and the residual bonding material can be cleaned by soaking in a cleaning solution such as NMP.

[0034] The technical solution of the present invention is further described in detail below through several embodiments and in conjunction with the accompanying drawings. However, the selected embodiments are only used to illustrate the present invention, and do not limit the scope of the present invention.

[0035] Example 1 This embodiment illustrates a manufacturing process of a double-sided lens, which is specifically as follows: 1. Use double-polished silicon wafers with a thickness 5um greater than the theoretical product thickness. The theoretical product thickness is 500um. Select a 505um silicon wafer thickness to compensate for the loss of vector height caused by over-etching during the etching process.

[0036] 2. The front and back marks are made by conventional double-sided photolithography and etching process; the double-sided marking points are used as the subsequent single-sided lens photolithography.

[0037] 3. Silicon lens is made into glue column by conventional photolithography process, and then the wafer is placed on Figure 3 The new reflux system provided is used for steam condensation circulation reflux, with a reflux temperature of 80°C and a reflux time of 2 minutes to obtain a uniform rubber ball lens.

[0038] 4. Then, through the ICP etching process, the appropriate etching procedure is selected according to the height relationship between the colloid ball and the back profile after etching. Etching gas: SF6: 50 sccm, CF4: 30 sccm, H2: 5 sccm, O2: 6 sccm, ICP: 1500 W, RF: 500 W, pressure: 1 Pa, back purge helium pressure: 1 kPa, cooler temperature 0 ° C, etching accurately transfers the colloid ball surface profile to the silicon substrate; 5. The completed first-side structure is integrated with the carrier through a temporary bonding method. The thickness of the bonding glue is 1.2 times the sagittal height of the first-side lens. Then it is baked for 10 minutes at a temperature of 120°C. Finally, the wafer and the carrier are bonded through a bonding device at 200°C, a bonding pressure of 4kN, and a bonding time of 5 minutes to ensure good bonding strength.

[0039] 6. After one bonding, annealing temperature is 200 degrees and time is 20 minutes.

[0040] 7. After annealing, the secondary bonding process is carried out with the process conditions of 220 degrees, bonding pressure of 5kN and bonding time of 10min.

[0041] 8. Then, the second lens processing is completed according to the same process as steps 3 and 4. After bonding, good heat dissipation can be guaranteed, and the transfer etching of the second lens structure can be completed with high quality.

[0042] 9. After the structure is completed, the bonding is debonded by hot sliding at 250°C, and finally the residual bonding material is cleaned by NMP immersion.

[0043] Comparative Example 1 This comparative example is substantially the same as Example 1, except that: The bonding process in steps 5-7 is omitted, and the wafer after the first lens is constructed is directly supported by a bracket to perform the second-side lithography and etching process.

[0044] Finally, due to the poor heat dissipation during the etching process, the first lens of the raised structure will lead to poor contact. In addition, the main heat dissipation system He gas cannot effectively circulate and contact, and the heat energy accumulates during the etching process, which eventually leads to the failure to dissipate heat in time. The photoresist carbonization paste appears abnormal on the top of the lens, and it does not have the protective effect that can be played on the first lens after bonding, and cannot prevent the lens surface from being scratched and dirty during the process. The microscopic photos of the obtained products are shown in the figure. Figure 4 shown.

[0045] Comparative Example 2 This comparative example is substantially the same as Example 1, except that: The annealing and secondary bonding processes in steps 6-7 are omitted, and the double-sided lens structure is directly prepared based on the primary bonding.

[0046] Finally, due to the poor heat dissipation during the etching process, micro bubbles will appear in the bonding glue during the first bonding, which is easy to cause voids. Under some etching conditions (such as etching conditions with high heat accumulation), poor heat dissipation will also occur. The microscopic photos of defective products are as follows: Figure 5 As shown; in Example 1, secondary bonding is performed after annealing, which greatly reduces the void problem caused by bubbles, thereby ensuring good system heat transfer between the lens structure, bonding glue, and the carrier, and avoiding the occurrence of the above problems to the greatest extent. The obtained product micrograph is shown as follows Figure 6 As shown, it is obviously smoother and of better quality.

[0047] Example 2 This embodiment is substantially the same as Embodiment 1, and the main difference is that: In steps 3 and 8, reflow is achieved by heating on a hot plate, and the heating temperature is consistent with that in Example 1.

[0048] The profile deviation of the lens structure finally obtained is significantly higher than that of Example 1, which indicates that the pilling of the photoresist is insufficient by using the conventional hot plate reflow method, and the surface profile is M-shaped, concave in the middle and asymmetrical on the left and right, and the PV value (indicating the standard surface profile deviation) is about 100nm. Figure 7 As shown; and the preferred method of condensation reflux provided by the present invention, the pilling of the photoresist is sufficient, the surface curve is symmetrical, and the PV value is about 30nm, such as Figure 8 shown.

[0049] Example 3 This embodiment illustrates a manufacturing process of a double-sided lens, which is specifically as follows: 1. Use double-polished silicon wafers with a thickness 10um greater than the theoretical product thickness. The theoretical product thickness is 500um. Select a 510um silicon wafer thickness to compensate for the loss of vector height caused by over-etching during the etching process.

[0050] 2. The front and back marks are made by conventional double-sided photolithography and etching process; the double-sided marking points are used as the subsequent single-sided lens photolithography.

[0051] 3. Silicon lens is made into glue column by conventional photolithography process, and then the wafer is placed on Figure 3 The new reflux system provided is used for steam condensation circulation reflux, with a reflux temperature of 95°C and a reflux time of 5 minutes to obtain a uniform gumball lens.

[0052] 4. Then, through the ICP etching process, the appropriate etching procedure is selected according to the height relationship between the colloid ball and the back profile after etching. Etching gas: SF6: 50 sccm, CF4: 30 sccm, H2: 5 sccm, O2: 6 sccm, ICP: 1500 W, RF: 500 W, pressure: 1 Pa, back purge helium pressure: 1 kPa, cooler temperature 0 ° C, etching accurately transfers the colloid ball surface profile to the silicon substrate; 5. The completed first-side structure is integrated with the carrier through a temporary bonding method. The thickness of the bonding glue is 1.1 times the sagittal height of the first-side lens. Then it is baked for 10 minutes at a temperature of 120°C. Finally, the wafer and the carrier are bonded through a bonding device at 220°C, a bonding pressure of 2kN, and a bonding time of 10 minutes to ensure good bonding strength.

[0053] 6. After one bonding, annealing temperature is 230 degrees and time is 10 minutes.

[0054] 7. After annealing, the secondary bonding process is carried out with the process conditions of 210 degrees, bonding pressure of 2kN and bonding time of 10min.

[0055] 8. Then, the second lens processing is completed according to the same process as steps 3 and 4. After bonding, good heat dissipation can be guaranteed, and the transfer etching of the second lens structure can be completed with high quality.

[0056] 9. After the structure is completed, the bonding is debonded by hot sliding at 260°C, and finally the residual bonding material is cleaned by NMP immersion.

[0057] Example 4 This embodiment illustrates a manufacturing process of a double-sided lens, which is specifically as follows: 1. Use double-polished silicon wafers with a thickness 5-10um greater than the theoretical product thickness. The theoretical product thickness is 500um. Select a 505um silicon wafer thickness to compensate for the loss of vector height caused by over-etching during the etching process.

[0058] 2. The front and back marks are made by conventional double-sided photolithography and etching process; the double-sided marking points are used as the subsequent single-sided lens photolithography.

[0059] 3. Silicon lens is made into glue column by conventional photolithography process, and then the wafer is placed on Figure 3 The new reflux system provided is used for steam condensation circulation reflux, with a reflux temperature of 90°C and a reflux time of 4 minutes to obtain a uniform gum ball lens.

[0060] 4. Then, through the ICP etching process, the appropriate etching procedure is selected according to the height relationship between the colloid ball and the back profile after etching. Etching gas: SF6: 50 sccm, CF4: 30 sccm, H2: 5 sccm, O2: 6 sccm, ICP: 1500 W, RF: 500 W, pressure: 1 Pa, back purge helium pressure: 1 kPa, cooler temperature 0 ° C, etching accurately transfers the colloid ball surface profile to the silicon substrate; 5. The completed first-side structure is integrated with the carrier through a temporary bonding method. The thickness of the bonding glue is 1.3 times the sagittal height of the first-side lens. Then it is baked for 15 minutes at a temperature of 110°C. Finally, the wafer and the carrier are bonded through a bonding device at 210°C, a bonding pressure of 6kN, and a bonding time of 8 minutes to ensure good bonding strength.

[0061] 6. After one bonding, annealing temperature is 220 degrees and time is 15 minutes.

[0062] 7. After annealing, the secondary bonding process is carried out with the process conditions of 200 degrees, bonding pressure of 6kN and bonding time of 8min.

[0063] 8. Then, the second lens processing is completed according to the same process as steps 3 and 4. After bonding, good heat dissipation can be guaranteed, and the transfer etching of the second lens structure can be completed with high quality.

[0064] 9. After the structure is completed, the bonding is removed by hot sliding at 245°C, and the residual bonding material is finally cleaned by NMP immersion.

[0065] Based on the above embodiments and comparative examples, it can be clearly seen that the manufacturing method provided in the embodiments of the present invention utilizes the idea of ​​temporary bonding to form a dense bond between the first microlens on the first surface and the carrier through a bonding material, and transforms the purging cooling of the first surface into the purging cooling of the carrier. In this way, the influence of the first microlens, especially the convex first microlens, on the purging of the cooling gas can be avoided, the efficiency and uniformity of the cooling gas purging can be improved, and the problem of partial carbonization of the photoresist colloid caused by local temperature runaway can be avoided, thereby avoiding the influence on the structure and appearance of the microlens on the second surface, and significantly reducing the defective rate during mass production.

[0066] It should be understood that the above embodiments are only for illustrating the technical concept and features of the present invention, and their purpose is to enable people familiar with the technology to understand the content of the present invention and implement it accordingly, and they cannot be used to limit the protection scope of the present invention. Any equivalent changes or modifications made according to the spirit of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for manufacturing a double-sided microlens structure, characterized in that: include: Providing a substrate having a first surface and a second surface disposed opposite to each other; The first surface is coated with photoresist and subjected to photolithography and reflow processes to form a first colloid; Performing pattern transfer etching on the first surface by using the first colloid to form a first microlens on the first surface; Bonding the first surface having the first microlens to a carrier wafer using a bonding material; The second surface is coated with photoresist and subjected to photolithography and reflow processes to form a second colloid; Performing pattern transfer etching on the second surface by using the second colloid to form a second microlens on the second surface, and applying forced cooling to the carrier during the etching process; The bonding between the first surface and the carrier is released to obtain a double-sided microlens structure.

2. The method according to claim 1, characterized in that: The bonding process specifically includes the steps of primary bonding, annealing treatment and secondary bonding; The primary bonding is used to achieve the first bonding between the first surface and the carrier. During the annealing treatment, the bonding pressure is removed and the temperature is used for treatment. During the secondary bonding, the bonding pressure continues to be applied.

3. The method according to claim 2, characterized in that: The temperature of the primary bonding and / or secondary bonding is 200-220°C, the time is 5-10min, and the pressure is 2-6kN; The annealing treatment is carried out at a temperature of 200-230 degrees and for a time of 10-20 minutes.

4. The method according to claim 2, characterized in that: The bonding process also includes: The bonding material is coated on the first surface with the first microlens to form a bonding adhesive layer, and the bonding material layer is formed after the adhesive is baked. Then, the bonding material layer is attached to the surface of the carrier for pressure bonding.

5. The method according to claim 4, characterized in that: The thickness of the bonding adhesive layer is 1.1-1.3 times the height or depth of the first microlens.

6. The method according to claim 1, characterized in that: The reflux process is carried out in a steam condensation cycle, and the steam condensation cycle specifically includes: The circulating liquid is heated to form vapor, and the lens structure to be processed by the reflow process is brought into contact with the vapor, so that the photoresist remaining after the photolithography process forms the first colloid or the second colloid under the action of its own surface tension.

7. The manufacturing method according to claim 6, characterized in that: The circulating liquid includes ethanol and / or isopropanol diluted with water; the heating temperature of the steam condensation cycle is 80-100° C. and the time is 2-5 minutes.

8. The manufacturing method according to claim 1, characterized in that: The debonding temperature of the bonding material is above 250°C.

9. The manufacturing method according to claim 1, characterized in that: The carrier is selected from a silicon wafer, and the thickness of the carrier is greater than the designed thickness of the double-sided microlens structure by 5-10 um.

10. The manufacturing method according to claim 1, characterized in that: The forced cooling includes cooling by circulating coolant and synchronously purging with cooling gas.

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