Manufacturing method of high-order lens and high-order lens

Abstract

The invention discloses a high-order lens manufacturing method and a high-order lens, which are characterized in that common ultraviolet lithography equipment is utilized, and according to the performance that molecular chains among molecules of positive photoresist after exposure are unlinked, the binding force among the molecules of the positive photoresist in an exposure area and a non-exposure area is different, so that the high-order lens is manufactured. The positive photoresist is subjected to exposure treatment with different depth sizes for multiple times, then the high-order concave lens is directly formed by utilizing the contraction force in the backflow process of the exposure area of the positive photoresist, and the high-order concave lens is formed by controlling the exposure dose and the exposure depth and selecting the performance of the positive photoresist under the condition of no high-expansion positive photoresist. The ultra-low concave lens (the angle is less than 3 degrees) is formed, so that high-order ultra-low concave lenses can be manufactured in batches, pattern transfer can be carried out through a nanoimprint technology and an etching technology, and high-order ultra-low convex lenses (the angle is less than 3 degrees) can be manufactured in batches. The technical scheme of the invention can be widely applied to the fields of various micro-nano processing, integrated circuits and optical devices.

Description

Technical Field

[0001] The invention belongs to the technical field of optoelectronic devices and semiconductor processes, and in particular relates to a method for manufacturing a high-order lens and the high-order lens. Background Art

[0002] With the development of Moore's Law, various semiconductors and optical devices, major semiconductor manufacturers have higher and higher requirements for the integration of components, and the trend of high-order integrated lenses replacing multi-lens groups is unstoppable. In the current market, the mainstream processing methods for high-order lenses are high-cost, difficult and non-batch processing methods such as mechanical processing, grayscale exposure and laser direct writing, which have caused the cost of high-order lenses to remain high.

[0003] Grayscale exposure technology is immature, with a long processing cycle and high process difficulty, and it is not possible to mass produce high-order lenses. Mechanical processing is often used in nanoimprint template production, with a processing cycle of more than one year and a cost of millions, which is relatively high.

[0004] Therefore, the above methods cannot be used for mass production of high-order lenses, and the production cost is high, and there are extremely high requirements for the accuracy and stability of the equipment. The equipment that can meet the requirements is often tens of millions of equipment, which is difficult for ordinary manufacturers to maintain.

[0005] Secondly, it is well known that low angle (<10°) has always been a difficult problem for reflow lens manufacturing, and for extreme angles (<3°), there is currently no suitable method on the market that can mass-produce extremely low lenses (angle <3°).

[0006] The information disclosed in this background technology section is only intended to enhance the understanding of the overall background of the invention and should not be regarded as an acknowledgment or any form of suggestion that the information constitutes the prior art already known to a person skilled in the art. Summary of the invention

[0007] The object of the present invention is to provide a method for manufacturing a high-order lens and the high-order lens, which can directly form a high-order concave lens by utilizing the contraction force during the reflow process of a positive photoresist.

[0008] In order to achieve the above object, a specific embodiment of the present invention provides a method for manufacturing a high-order lens, comprising:

[0009] Provide wafers;

[0010] Performing a positive photoresist coating on the first surface of the wafer;

[0011] Performing a first exposure process on the positive photoresist on the first surface of the wafer using a first mask to form a first exposure area;

[0012] Performing a second exposure process on the positive photoresist on the first surface of the wafer using a second mask to form a second exposure area, wherein the second exposure area partially overlaps with the first exposure area;

[0013] Thermal reflow treatment uses the molecular chains of positive photoresist to melt after exposure, so that the binding force between positive photoresist molecules in the exposed area and the non-exposed area is different. Through thermal reflow, the molecules in the exposed area are guided to shrink toward the non-exposed area to form a high-order concave rubber ball lens;

[0014] The high-order concave rubber ball lens is transferred to the wafer through etching technology to form a high-order concave lens.

[0015] In one or more embodiments of the present invention, before performing the step of coating the first surface of the wafer with a positive photoresist, the method further includes:

[0016] The steps for pre-processing the wafer.

[0017] In one or more embodiments of the present invention, the wafer is pre-processed, including:

[0018] cleaning and drying the wafer;

[0019] Placing the wafer in an oven for hexamethyldisilazane coating;

[0020] The coating time is 10min-14min, and the oven temperature is 110℃-130℃.

[0021] In one or more embodiments of the present invention, a corresponding optical mask is processed according to the actual required size of the high-order concave lens, and the optical mask at least includes a first mask and a second mask.

[0022] In one or more embodiments of the present invention, the conditions of the first exposure process are:

[0023] Exposure dose range: 10mj-40mj;

[0024] Side length or diameter range of exposure area: 20μm-500μm;

[0025] Exposure depth range: 0.3μm-20μm; and / or,

[0026] The conditions for the second exposure process are:

[0027] Exposure dose range: 10mj-40mj;

[0028] Side length or diameter range of exposure area: 20μm-500μm;

[0029] Exposure depth range: 0.3μm-20μm.

[0030] In one or more embodiments of the present invention, the width of the second exposure area is smaller than the width of the first exposure area; and / or,

[0031] The depth of the second exposure area is greater than the depth of the first exposure area.

[0032] In one or more embodiments of the present invention, before the step of thermal reflow treatment, the positive photoresist on the first surface of the wafer may be continuously exposed for a corresponding number of times according to the requirements of the levels of the high-order concave lenses.

[0033] In one or more embodiments of the present invention, the positive photoresist has a coating thickness greater than or equal to the depth of all exposure areas.

[0034] In one or more embodiments of the present invention, the high-order concave lens is used as a hard template, an imprinting glue is coated on the corresponding wafer surface, a high-order convex lens is manufactured by nanoimprinting technology, and the pattern is transferred on the wafer by etching technology.

[0035] A specific embodiment of the present invention provides a high-order lens manufactured by using the above-mentioned method for manufacturing a high-order lens.

[0036] Compared with the prior art, the method for manufacturing a high-order lens and the high-order lens of the present invention utilize the shrinkage force of the positive photoresist during the reflow process to directly form a high-order concave lens through multiple exposures without the need for development, and can be widely used in various micro-nano processing, integrated circuits and optical device fields.

[0037] The method for manufacturing a high-order lens and the high-order lens of the present invention can form an extremely low concave lens (angle <3°) by controlling the exposure dose, exposure depth and performance selection of the positive photoresist without high expansion positive photoresist, and can also perform pattern transfer through nanoimprint technology and etching technology to manufacture an extremely low convex lens (angle <3°). BRIEF DESCRIPTION OF THE DRAWINGS

[0038] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the prior art descriptions are briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in the present invention, and for ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0039] Figure 1 is a process flow chart of a method for manufacturing a high-order lens in one embodiment of the present invention;

[0040] Figure 2 A diagram of a high-order concave lens manufacturing process of a method for manufacturing a high-order lens in one embodiment of the present invention. DETAILED DESCRIPTION

[0041] In order to enable those skilled in the art to better understand the technical solutions in the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of the present invention.

[0042] High-order lens: Aspheric optical element is a product different from traditional spherical element. For a spherical surface, its radius of curvature is the only surface shape parameter, while there are more parameters to describe the shape of an aspheric surface. The common aspheric loss height description formula is as follows:

[0043]

[0044] In the above formula, r is the radial distance between the point on the aspherical surface and the optical axis of the aspherical surface, and z(r) is the corresponding height loss at this distance. c is the vertex curvature of the aspherical surface, and its reciprocal is the vertex curvature radius of the aspherical surface. k is called the cone coefficient, and its value is -e 2 , where e is the geometric eccentricity, a4, a6, a8, a n It is the coefficient corresponding to the high-order term of the aspheric surface. From the above aspheric surface equation, we can see that the more shape parameters of the aspheric surface can provide flexible freedom for the design of the aspheric surface.

[0045] As mentioned in the background technology, in the prior art, the commonly used production methods for high-order lenses are grayscale exposure and mechanical processing. However, the grayscale exposure method is immature, has a long processing cycle, and is difficult to manufacture in batches. Mechanical processing is commonly used in nanoimprint template production, and the processing cycle is expected to be more than one year, with a cost of millions, which is relatively high.

[0046] Therefore, the above methods cannot be used for mass production of high-order lenses, and the production cost is high, and there are extremely high requirements for the accuracy and stability of the equipment. The equipment that can meet the requirements is often tens of millions of equipment, which is difficult for ordinary manufacturers to maintain.

[0047] Secondly, it is well known that low angle (<10°) has always been a difficult problem for reflow lens manufacturing, and for extreme angles (<3°), there is currently no suitable method on the market that can mass-produce extremely low lenses (angle <3°).

[0048] In order to solve the above technical problems, the present application provides a method for manufacturing a high-order lens and a high-order lens, using commonly used ultraviolet lithography equipment, according to the molecular chain unzipping between the molecules of the positive photoresist after exposure, so that the molecular binding force between the positive photoresist molecules in the exposed area and the non-exposed area is different, the positive photoresist is subjected to multiple exposure treatments of different depths and sizes, and then the shrinkage force in the positive photoresist exposure area reflow process is used to directly form a high-order concave lens, and by controlling the exposure dose and the performance selection of the positive photoresist, an extremely low concave lens (angle <3°) is formed in the absence of a high-expansion positive photoresist, so as to batch produce high-order extremely low concave lenses, and the pattern transfer can be performed by nanoimprinting technology to batch produce high-order extremely low convex lenses (angle <3°). The technical solution of the present application can be widely used in various micro-nano processing, integrated circuits and optical device fields.

[0049] like Figure 1 As shown, a method for manufacturing a high-order lens in an embodiment of the present invention specifically includes the following steps:

[0050] S1, provides wafer.

[0051] S2, pre-processing the wafer.

[0052] S3, performing coating of positive photoresist on the first surface of the wafer.

[0053] S4, performing a first exposure process on the positive photoresist on the first surface of the wafer using a first mask to form a first exposure area.

[0054] S5, performing a second exposure process on the positive photoresist on the first surface of the wafer using a second mask to form a second exposure area, wherein the second exposure area partially overlaps with the first exposure area.

[0055] S6, thermal reflow treatment, utilizes the molecular chains between the positive photoresist molecules to unwind after exposure, so that there is a difference in the binding force between the positive photoresist molecules in the exposed area and the non-exposed area. Through thermal reflow, the molecules in the exposed area are guided to shrink toward the non-exposed area to form a high-order concave rubber ball lens.

[0056] S7, transferring the high-order concave rubber ball lens to the wafer through etching technology to form a high-order concave lens.

[0057] Among them, in step S2, pre-treatment of the wafer specifically includes: cleaning and drying the wafer; placing the wafer in an oven for hexamethyldisilazane coating, the coating time is 10min-14min, and the oven temperature is 110℃-130℃.

[0058] In step S3, a positive photoresist with low expansion is selected and evenly coated on the first surface of the wafer at a spin coating condition of 2500 rpm to 3500 rpm to a thickness of 2 μm to 6 μm.

[0059] In steps S4 and S5, the first mask and the second mask can be processed according to the actual required size of the high-order concave lens. For example, if the manufactured high-order lens is a long strip concave lens, the pattern shapes on the first mask and the second mask should both be rectangular. The conditions for the first exposure treatment are: exposure dose range: 10mj-40mj; side length or diameter range of the exposure area: 20μm-500μm; exposure depth range: 0.3μm-20μm. The conditions for the second exposure treatment are: exposure dose range: 10mj-40mj; side length or diameter range of the exposure area: 20μm-500μm; exposure depth range: 0.3μm-20μm. The width of the second exposure area is smaller than the width of the first exposure area, the depth of the second exposure area is greater than the depth of the first exposure area, and the uniform thickness of the positive photoresist is greater than or equal to the depth of all exposure areas.

[0060] By controlling the exposure dose and exposure depth, it is possible to produce an extremely low concave lens (angle <3°).

[0061] Before the thermal reflow treatment in step S6, the positive photoresist on the first surface of the wafer can be exposed for a corresponding number of times using an optical mask according to the requirements of the layers of the high-order concave lens, and the area formed by each exposure partially overlaps with the first exposure area and is deeper than the depth of the first exposure area. Except for the first exposure area, the area formed by each subsequent exposure can partially overlap or not overlap with the area formed by other exposure processes.

[0062] The above-mentioned specific production process can be used for individual or batch production of high-order ultra-low concave lenses. On this basis, the high-order ultra-low concave lenses are used as hard templates, and the imprint glue is coated on the corresponding wafer surface. The high-order ultra-low convex lenses are produced by nanoimprint technology, and the patterns are transferred on the wafer by etching technology to complete the production of high-order ultra-low convex lenses.

[0063] The following is combined with Figure 2 , the method for manufacturing the high-order lens of the present application is described in detail through a specific embodiment to facilitate further understanding of the technical solution of the present application.

[0064] refer to Figure 2As shown, the wafer 10 is first pre-treated: the wafer 10 is cleaned and dried, that is, the wafer 10 is first cleaned by the RCA cleaning process, and after the cleaning is completed, the wafer 10 is placed on a high-temperature heating plate to thoroughly dry the moisture on the surface of the wafer 10. Then the wafer 10 is placed in an oven for HMDS-hexamethyldisilazane (adhesion enhancer) coating for 10 minutes to 14 minutes at a temperature of 110°C to 130°C.

[0065] Secondly, according to the design requirements, the first surface of the wafer 10 is coated with a positive photoresist. A layer of positive photoresist 20 with uniform thickness is coated on the top surface of the wafer 10 by a spin coating method. The positive photoresist is a low-expansion photoresist, such as AZ5214, S6130, and AZ4620 series. The spin coating method refers to the use of a spin coater to evenly coat the positive photoresist on the top surface of the wafer 10, while preventing bubbles from appearing in the photoresist. After the spin coating is completed, the self-leveling effect of the photoresist is used to stand for a certain period of time to remove the ripples generated by the spin coating. During the coating, the spin coater speed is 3000rpm and the coating thickness is 5μm.

[0066] According to the required order of the high-order concave lens and the required ROC (radius of curvature) of each lens of the high-order concave lens, the photolithography mask is manufactured. In this embodiment, it is a four-order concave lens, and four photolithography masks are manufactured.

[0067] Next, step exposure is performed. The first mask is covered on the top surface of the positive photoresist 20, and then the wafer 10 is placed in the center of the photolithography machine tray, and then the positive photoresist 20 is exposed to ultraviolet light using contact photolithography technology to form a first exposure area A. During ultraviolet exposure, the exposure conditions are set according to the ROC (radius of curvature) of the required concave lens. Exemplarily, the conditions for the first exposure treatment are: exposure dose range: 10mj-40mj; side length or diameter range of the exposure area: 20μm-500μm; exposure depth range: 0.3μm-20μm.

[0068] After the first exposure, the first mask is removed, and no development is required. The second mask is directly covered on the top surface of the positive photoresist 20. Then the wafer 10 is placed in the center of the photolithography machine tray, and then the positive photoresist 20 is exposed to step UV by contact lithography technology to form a second exposure area B. The second exposure area B partially overlaps with the first exposure area A. During UV exposure, the exposure conditions are set according to the ROC (radius of curvature) of the required concave lens. Exemplarily, the conditions for the second exposure process are: exposure dose range: 10mj-40mj; side length or diameter range of the exposure area: 20μm-500μm; exposure depth range: 0.3μm-20μm.

[0069] After the second exposure, the second mask is removed, and no development is required. The third mask is directly covered on the top surface of the positive photoresist 20. Then the wafer 10 is placed in the center of the lithography machine tray, and then the positive photoresist 20 is exposed to step UV by contact lithography technology to form a third exposure area C. The third exposure area C partially overlaps with the first exposure area A, and the third exposure area C does not overlap with the second exposure area B and is arranged in parallel. During UV exposure, the exposure conditions are set according to the ROC (radius of curvature) of the required concave lens. Exemplarily, the conditions for the third exposure process are: exposure dose range: 10mj-40mj; side length or diameter range of the exposure area: 20μm-500μm; exposure depth range: 0.3μm-20μm.

[0070] After the third exposure, the third mask is removed, and no development is required. The fourth mask is directly covered on the top surface of the positive photoresist 20. Then the wafer 10 is placed in the center of the photolithography machine tray, and then the positive photoresist 20 is subjected to step UV exposure using contact lithography technology to form a fourth exposure area D. The fourth exposure area D partially overlaps with the first exposure area A, and the fourth exposure area D partially overlaps with the second exposure area B and the third exposure area C, and the fourth exposure area D is vertically arranged with the second exposure area B and the third exposure area C. During UV exposure, the exposure conditions are set according to the ROC (radius of curvature) of the desired concave lens. Exemplarily, the conditions for the fourth exposure process are: exposure dose range: 10mj-40mj; side length or diameter range of the exposure area: 20μm-500μm; exposure depth range: 0.3μm-20μm.

[0071] Then, the wafer 10 with the positive photoresist 20 is reflowed. The wafer 10 is placed in an oven so that the bottom surface of the wafer 10 is fully in contact with the oven heating plate for heating. After the heating is completed, the wafer 10 is taken out and left to cool to room temperature. At this time, the positive photoresist forms a photoresist film plate, and the top surface of the photoresist film plate is a high-order extremely low concave gum ball lens.

[0072] After the step-by-step exposure step, there is no need for development. The molecular chains of the positive photoresist can be directly melted after exposure, so that there is a difference in the binding force between the positive photoresist molecules in the exposed area and the non-exposed area. After heating, the photoresist in the exposed area shrinks toward the non-exposed area, forming the designed high-order extremely low concave gumball lens.

[0073] Finally, the high-order extremely low-concave rubber ball lens is transferred to the wafer 10 through a plasma etching process to form a wafer-level high-order extremely low-concave lens.

[0074] Optionally, the high-order extremely low concave lens manufactured above is pattern-transferred by nanoimprinting technology to manufacture a high-order extremely low convex lens.

[0075] Embodiment 1:

[0076] The wafer 10 is cleaned and dried, that is, the RCA cleaning process is first used to clean the wafer 10, and after cleaning, the wafer 10 is placed on a high-temperature heating plate to thoroughly dry the moisture on the surface of the wafer 10. The wafer 10 is then placed in an oven for HMDS-hexamethyldisilazane (adhesion enhancer) coating for 12 minutes at a temperature of 120°C.

[0077] According to the design requirements, the first surface of the wafer 10 is coated with a positive photoresist. A layer of positive photoresist 20 with uniform thickness is coated on the top surface of the wafer 10 by a spin coating method. The positive photoresist is AZ5214. The spin coating method refers to coating the positive photoresist uniformly on the top surface of the wafer 10 by a spin coater, while preventing bubbles from appearing in the photoresist. After the spin coating is completed, the self-leveling effect of the photoresist is used to stand for 40 minutes to remove the ripples generated by the spin coating. During the coating, the spin coater speed is 3000rpm and the coating thickness is 2 microns.

[0078] The first mask is covered on the top surface of the positive photoresist 20, and then the wafer 10 is placed in the center of the photolithography machine tray, and then the positive photoresist 20 is exposed to ultraviolet light using contact photolithography technology to form a first exposure area A. During ultraviolet exposure, the exposure dose is 10 mj; the diameter of the exposure area is a circle with a diameter of 127 μm; and the exposure depth is 0.5 μm.

[0079] Remove the first mask, without developing, directly cover the top surface of the positive photoresist 20 with the second mask, then place the wafer 10 in the center of the photolithography machine tray, and then use contact photolithography technology to perform step UV exposure on the positive photoresist 20 to form the second exposure area B. During UV exposure, the exposure dose is 15mj; the side length of the exposure area is 135*50μm 2 ; Exposure depth is 1μm.

[0080] The wafer 10 with the positive photoresist 20 is reflowed. The wafer 10 is placed in an oven so that the bottom surface of the wafer 10 is in full contact with the oven heating plate. The oven temperature is set to 65°C for heating for 5 minutes. After the heating is completed, the oven temperature is raised to 95°C and heated for another 10 minutes. After the heating is completed, the wafer 10 is taken out and allowed to cool to room temperature. At this time, the positive photoresist forms a photoresist film plate, and the top surface of the photoresist film plate is a high-order concave rubber ball lens. The angle of the high-order extremely low concave rubber ball lens is 3°.

[0081] The high-order extremely low-concave rubber ball lens is transferred to the wafer 10 through a plasma etching process to form a wafer-level high-order extremely low-concave lens.

[0082] Embodiment 2:

[0083] The wafer 10 is cleaned and dried, that is, the RCA cleaning process is first used to clean the wafer 10, and after cleaning, the wafer 10 is placed on a high-temperature heating plate to thoroughly dry the moisture on the surface of the wafer 10. The wafer 10 is then placed in an oven for HMDS-hexamethyldisilazane (adhesion enhancer) coating for 12 minutes at a temperature of 120°C.

[0084] According to the design requirements, the first surface of the wafer 10 is coated with a positive photoresist. A layer of positive photoresist 20 with uniform thickness is coated on the top surface of the wafer 10 by a spin coating method. The positive photoresist is S6130. The spin coating method refers to coating the positive photoresist uniformly on the top surface of the wafer 10 by a spin coater, while preventing bubbles from appearing in the photoresist. After the spin coating is completed, the self-leveling effect of the photoresist is used to stand for 40 minutes to remove the ripples generated by the spin coating. During the coating, the spin coater speed is 2500rpm, and the coating thickness is 3 microns.

[0085] The first mask is covered on the top surface of the positive photoresist 20, and then the wafer 10 is placed in the center of the photolithography machine tray, and then the positive photoresist 20 is exposed to ultraviolet light using contact photolithography technology to form a first exposure area A. During ultraviolet exposure, the exposure dose is 10 mj; the diameter of the exposure area is a circle with a diameter of 600 μm; and the exposure depth is 0.3 μm.

[0086] Remove the first mask, without developing, directly cover the top surface of the positive photoresist 20 with the second mask, then place the wafer 10 in the center of the photolithography machine tray, and then use contact photolithography technology to perform step UV exposure on the positive photoresist 20 to form the second exposure area B. During UV exposure, the exposure dose is 10mj; the side length of the exposure area is 100*700μm 2 ; Exposure depth is 0.5μm.

[0087] The wafer 10 with the positive photoresist 20 is reflowed. The wafer 10 is placed in an oven so that the bottom surface of the wafer 10 is in full contact with the oven heating plate. The oven temperature is set to 65°C for heating for 5 minutes. After the heating is completed, the oven temperature is raised to 95°C and heated for another 10 minutes. After the heating is completed, the wafer 10 is taken out and allowed to cool to room temperature. At this time, the positive photoresist forms a photoresist film plate, and the top surface of the photoresist film plate is a high-order concave rubber ball lens. The angle of the high-order extremely low concave rubber ball lens is 1°.

[0088] The high-order extremely low-concave rubber ball lens is transferred to the wafer 10 through a plasma etching process to form a wafer-level high-order extremely low-concave lens.

[0089] Embodiment 3:

[0090] The wafer 10 is cleaned and dried, that is, the RCA cleaning process is first used to clean the wafer 10, and after cleaning, the wafer 10 is placed on a high-temperature heating plate to thoroughly dry the moisture on the surface of the wafer 10. The wafer 10 is then placed in an oven for HMDS-hexamethyldisilazane (adhesion enhancer) coating for 12 minutes at a temperature of 120°C.

[0091] According to the design requirements, the first surface of the wafer 10 is coated with a positive photoresist. A layer of positive photoresist 20 with uniform thickness is coated on the top surface of the wafer 10 by a spin coating method. The positive photoresist is AZ4620. The spin coating method refers to coating the positive photoresist uniformly on the top surface of the wafer 10 by a spin coater, while preventing bubbles from appearing in the photoresist. After the spin coating is completed, the self-leveling effect of the photoresist is used to stand for 40 minutes to remove the ripples generated by the spin coating. During the coating, the spin coater speed is 3000rpm, and the coating thickness is 6 microns.

[0092] The first mask is covered on the top surface of the positive photoresist 20, and then the wafer 10 is placed in the center of the photolithography machine tray, and then the positive photoresist 20 is exposed to ultraviolet light using contact photolithography technology to form a first exposure area A. During ultraviolet exposure, the exposure dose is 50 mj; the diameter of the exposure area is a circle with a diameter of 700 μm; and the exposure depth is 2 μm.

[0093] Remove the first mask, without developing, and directly cover the top surface of the positive photoresist 20 with the second mask, then place the wafer 10 in the center of the photolithography machine tray, and then use contact photolithography technology to perform step UV exposure on the positive photoresist 20 to form the second exposure area B. During UV exposure, the exposure dose is 20mj; the side length of the exposure area is 300*100μm 2 ; Exposure depth is 3μm.

[0094] The wafer 10 with the positive photoresist 20 is reflowed. The wafer 10 is placed in an oven so that the bottom surface of the wafer 10 is in full contact with the oven heating plate. The oven temperature is set to 65°C for heating for 5 minutes. After the heating is completed, the oven temperature is raised to 95°C and heated for another 10 minutes. After the heating is completed, the wafer 10 is taken out and allowed to stand and cool to room temperature. At this time, the positive photoresist forms a photoresist film plate, and the top surface of the photoresist film plate is a high-order concave rubber ball lens. The angle of the high-order extremely low concave rubber ball lens is 4°.

[0095] The high-order extremely low-concave rubber ball lens is transferred to the wafer 10 through a plasma etching process to form a wafer-level high-order extremely low-concave lens.

[0096] Embodiment 4:

[0097] The difference between Example 4 and Example 3 is that the exposure conditions are different. In the first exposure, the exposure dose is 60 mj; the side length of the exposure area is 700*700 μm. 2; The exposure depth is 3μm. During the second exposure, the exposure dose is 60mj; the side length of the exposure area is 200*900μm 2 ; Exposure depth is 5μm.

[0098] The resulting high-order extremely low concave lens has an angle of 5°.

[0099] It can be seen from Examples 1-4 that the method for manufacturing high-order lenses and the high-order lenses of the present application utilize the shrinkage force during the reflow process of the positive photoresist to directly form high-order concave lenses through multiple exposures without the need for development, and by controlling the exposure conditions and the performance selection of the positive photoresist, extremely low lenses (angle <3°) can be mass-produced.

[0100] Compared with the prior art, the method for manufacturing a high-order lens and the high-order lens of the present invention utilize the shrinkage force of the positive photoresist during the reflow process to directly form a high-order concave lens through multiple exposures without the need for development, and can be widely used in various micro-nano processing, integrated circuits and optical device fields.

[0101] The method for manufacturing a high-order lens and the high-order lens of the present invention can form an extremely low concave lens (angle <3°) by controlling the exposure dose, exposure depth and performance selection of the positive photoresist without high expansion positive photoresist, such as AZ5214 and S6130 series, and can also perform pattern transfer through nanoimprint technology and etching technology to manufacture an extremely low convex lens (angle <3°).

[0102] It will be apparent to those skilled in the art that the invention is not limited to the details of the exemplary embodiments described above and that the invention can be implemented in other specific forms without departing from the spirit or essential features of the invention. Therefore, the embodiments should be considered exemplary and non-limiting in all respects, and the scope of the invention is defined by the appended claims rather than the foregoing description, and it is intended that all variations falling within the meaning and scope of the equivalent elements of the claims be included in the invention. Any reference numeral in a claim should not be considered as limiting the claim to which it relates.

[0103] In addition, it should be understood that although the present specification is described according to implementation modes, not every implementation mode contains only one independent technical solution. This description of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment may also be appropriately combined to form other implementation modes that can be understood by those skilled in the art.

Claims

1. A method for manufacturing a high-order lens, characterized in that: include: Provide wafers; Performing a positive photoresist coating on the first surface of the wafer; Performing a first exposure process on the positive photoresist on the first surface of the wafer using a first mask to form a first exposure area; Performing a second exposure process on the positive photoresist on the first surface of the wafer using a second mask to form a second exposure area, wherein the second exposure area partially overlaps with the first exposure area; Thermal reflow treatment uses the molecular chains of positive photoresist to melt after exposure, so that the binding force between positive photoresist molecules in the exposed area and the non-exposed area is different. Through thermal reflow, the molecules in the exposed area are guided to shrink toward the non-exposed area to form a high-order concave rubber ball lens; The high-order concave rubber ball lens is transferred to the wafer through etching technology to form a high-order concave lens.

2. The method for manufacturing a high-order lens according to claim 1, characterized in that: Before performing a positive photoresist coating step on the first surface of the wafer, the method further comprises: The steps for pre-processing the wafer.

3. The method for manufacturing a high-order lens according to claim 2, characterized in that: Pre-process the wafer, including: cleaning and drying the wafer; Placing the wafer in an oven for hexamethyldisilazane coating; The coating time is 10min-14min, and the oven temperature is 110℃-130℃.

4. The method for manufacturing a high-order lens according to claim 1, characterized in that: According to the actual required size of the high-order concave lens, a corresponding optical mask is processed, and the optical mask at least includes a first mask and a second mask.

5. The method for manufacturing a high-order lens according to claim 1, characterized in that: The conditions of the first exposure process are: Exposure dose range: 10mj-40mj; Side length or diameter range of exposure area: 20μm-500μm; Exposure depth range: 0.3μm-20μm; and / or, The conditions for the second exposure process are: Exposure dose range: 10mj-40mj; Side length or diameter range of exposure area: 20μm-500μm; Exposure depth range: 0.3μm-20μm.

6. The method for manufacturing a high-order lens according to claim 1, characterized in that: The width of the second exposure area is smaller than the width of the first exposure area; and / or, The depth of the second exposure area is greater than the depth of the first exposure area.

7. The method for manufacturing a high-order lens according to claim 1, characterized in that: Before the step of heat reflow treatment, the positive photoresist on the first surface of the wafer may be further exposed for a corresponding number of times according to the requirements of the layers of the high-order concave lenses.

8. The method for manufacturing a high-order lens according to claim 1, characterized in that: The positive photoresist has a uniform coating thickness greater than or equal to the depth of all exposure areas.

9. The method for manufacturing a high-order lens according to claim 1, characterized in that: The high-order concave lens is used as a hard template, an imprint glue is coated on the surface of the corresponding wafer, a high-order convex lens is manufactured by nanoimprint technology, and the pattern is transferred on the wafer by etching technology.

10. A high-order lens manufactured by the method for manufacturing a high-order lens according to any one of claims 1 to 9.

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