Method for manufacturing high-order lens and high-order lens

Abstract

The application discloses a manufacturing method of a high-order lens and the high-order lens. By using a common ultraviolet photoetching device, a performance that a difference in intermolecular binding force of positive photoresist in exposed areas and non-exposed areas is generated after molecular chain unzipping of the positive photoresist after exposure is utilized, the positive photoresist is subjected to multiple exposure treatments of different depth sizes, and then, by using the shrinkage force in the reflow process of the exposed areas of the positive photoresist, a high-order concave lens is directly formed. By controlling the exposure dose, the exposure depth and the performance selection of the positive photoresist, an extremely low concave lens (an angle < 3°) is formed under the condition that no high-expansion positive photoresist is used. The high-order extremely low concave lens can be mass-produced, and the nano-imprinting technology and the etching technology can be used for pattern transfer, so that the high-order extremely low convex lens (an angle < 3°) can be mass-produced. The technical scheme of the application can be widely used in various micro-nano processing, integrated circuits and optical device fields.

Description

Technical Field

[0001] This invention belongs to the fields of optoelectronic devices and semiconductor process technology, and specifically relates to a method for fabricating a high-order lens and the high-order lens itself. Background Technology

[0002] With the advancement of Moore's Law, various semiconductor and optical devices are facing increasingly higher integration requirements from major semiconductor manufacturers. The trend of high-order integrated lenses replacing multi-lens groups is unstoppable. Currently, the mainstream processing methods for high-order lenses in the market are high-cost, difficult, and non-mass-producible methods such as machining, grayscale exposure, and laser direct writing, resulting in persistently high costs for high-order lenses.

[0003] Grayscale exposure technology is immature, has a long processing cycle, and is difficult to manufacture, making it impossible to mass-produce high-end lenses. Machining methods are often used for nanoimprint template production, with a processing cycle expected to be over one year and costs in the millions, making them relatively expensive.

[0004] Therefore, none of the above methods can be used for mass production of high-end lenses, and the production cost is high, requiring extremely high precision and stability from the equipment. Equipment that meets these requirements is typically in the tens of millions of dollars, which is difficult for ordinary manufacturers to maintain.

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

[0006] The information disclosed in this background section is intended only to enhance the understanding of the overall background of the invention and should not be construed as an admission or in any way implying that the information constitutes prior art known to those skilled in the art. Summary of the Invention

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

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

[0009] Provide wafers;

[0010] A positive photoresist is homogenized on the first surface of the wafer;

[0011] The first mask is used to perform a first exposure treatment on the positive photoresist on the first surface of the wafer to form a first exposure area;

[0012] A second mask is used to perform a second exposure process on the positive photoresist on the first surface of the wafer to form a second exposure area, which partially overlaps with the first exposure area;

[0013] Thermal reflow treatment utilizes the unchaining of molecular chains between molecules in positive photoresist after exposure, creating a difference in the binding force between positive photoresist molecules in the exposed and unexposed areas. Through thermal reflow, the molecules in the exposed area are guided to shrink towards the unexposed area, forming a high-order concave photoresist spherical lens.

[0014] The high-order concave lens is transferred onto the wafer using etching technology to form a high-order concave lens.

[0015] In one or more embodiments of the present invention, prior to the spin coating step of positive photoresist on the first surface of the wafer, the method further includes:

[0016] The steps for preprocessing wafers.

[0017] In one or more embodiments of the present invention, preprocessing of the wafer includes:

[0018] Clean and dry the wafer;

[0019] The wafer is placed in an oven for hexamethyldisilazane coating;

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

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

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

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

[0024] The side length or diameter range of the exposure area is 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] The side length or diameter range of the exposure area is 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, prior to the thermal reflow process, the positive photoresist on the first surface of the wafer may be exposed for a corresponding number of exposure levels according to the layer requirements of the higher-order concave lens.

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

[0034] In one or more embodiments of the present invention, the high-order concave lens is used as a hard template, imprinting adhesive is coated on the corresponding wafer surface, and the high-order convex lens is fabricated 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 using the above-described high-order lens manufacturing method.

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

[0037] The high-order lens fabrication method and high-order lens of the present invention can form an extremely low concave lens (angle < 3°) under the condition of no high expansion positive photoresist by controlling the exposure dose, exposure depth and the performance selection of positive photoresist. Furthermore, an extremely low convex lens (angle < 3°) can be fabricated by pattern transfer through nanoimprinting technology and etching technology. Attached Figure Description

[0038] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0039] Figure 1 This is a process flow diagram of a method for manufacturing a high-order lens according to an embodiment of the present invention;

[0040] Figure 2 This is a process diagram of the fabrication of a high-order concave lens according to an embodiment of the present invention. Detailed Implementation

[0041] To enable those skilled in the art to better understand the technical solutions of this invention, the technical solutions of the embodiments of this invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are merely some embodiments of this invention, and not all embodiments. Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of this invention.

[0042] High-order lenses: Aspherical optical elements, a type of product distinct from traditional spherical elements. For a spherical surface, its radius of curvature is the only surface shape parameter, while aspherical surfaces have more parameters describing their shape. Common formulas describing aspherical lens height are shown below:

[0043]

[0044] In the above formula, r is the radial distance between a point on the aspherical surface and the optical axis of the aspherical surface, and z(r) is the height difference at that distance. c is the vertex curvature of the aspherical surface, and its reciprocal is the vertex radius of curvature of the aspherical surface. k is called the conic coefficient, and its value is -e. 2 Where e is the geometric eccentricity, a4, a6, a8, a n These are the coefficients corresponding to higher-order terms in aspherical surfaces. As can be seen from the aspherical equations above, the numerous shape parameters of aspherical surfaces provide flexible degrees of freedom for their design.

[0045] As mentioned in the background section, existing technologies commonly use grayscale exposure and machining methods to fabricate high-order lenses. However, grayscale exposure is a technically immature method with a long processing cycle and high technological difficulty, making it unsuitable for mass production of high-order lenses. Machining is often used for fabricating nanoimprint templates, with a processing cycle estimated to be over one year and costs in the millions, making it quite expensive.

[0046] Therefore, none of the above methods can be used for mass production of high-end lenses, and the production cost is high, requiring extremely high precision and stability from the equipment. Equipment that meets these requirements is typically in the tens of millions of dollars, which is difficult for ordinary manufacturers to maintain.

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

[0048] To address the aforementioned technical problems, this application provides a method for fabricating a high-order lens and the high-order lens itself. Utilizing common ultraviolet lithography equipment, and based on the property that the molecular chains of positive photoresist unwind after exposure, creating a difference in the binding forces between the exposed and unexposed areas, the positive photoresist undergoes multiple exposures at different depths. Then, by utilizing the shrinkage force during the reflow process of the exposed areas, a high-order concave lens is directly formed. Furthermore, by controlling the exposure dose and selecting appropriate properties for the positive photoresist, an extremely low-concavity lens (angle < 3°) can be formed without highly expanding positive photoresist. This method allows for the mass production of high-order extremely low-concavity lenses, and the pattern can be transferred using nanoimprint lithography to mass-produce high-order extremely low-convex lenses (angle < 3°). The technical solution of this application can be widely used in various micro / nano fabrications, integrated circuits, and optical devices.

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

[0050] S1 provides wafers.

[0051] S2, preprocessing the wafer.

[0052] S3, perform positive photoresist homogenization on the first surface of the wafer.

[0053] S4, the first mask is used to perform the first exposure treatment on the positive photoresist on the first surface of the wafer to form the first exposure area.

[0054] S5, a second mask is used to perform a second exposure process on the positive photoresist on the first surface of the wafer to form a second exposure area, which partially overlaps with the first exposure area.

[0055] S6, thermal reflow treatment, utilizes the unchaining of molecular chains between molecules in the positive photoresist after exposure, creating a difference in the binding force between positive photoresist molecules in the exposed and unexposed areas. Through thermal reflow, the molecules in the exposed area are guided to shrink towards the unexposed area, forming a high-order concave photoresist spherical lens.

[0056] S7 uses etching technology to transfer a high-order concave lens onto the wafer, forming a high-order concave lens.

[0057] In step S2, the pretreatment of the wafer specifically includes: cleaning and drying the wafer; placing the wafer in an oven for coating with hexamethyldisilazane for 10-14 minutes, and the oven temperature for 110-130°C.

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

[0059] In steps S4 and S5, the first and second masks can be fabricated according to the actual dimensions required for the high-order concave lens. For example, if the high-order lens being fabricated is a long, narrow concave lens, then the patterns on both the first and second masks should be rectangular. The conditions for the first exposure process are: exposure dose range: 10 mJ-40 mJ; side length or diameter range of the exposure area: 20 μm-500 μm; exposure depth range: 0.3 μm-20 μm. The conditions for the second exposure process are: exposure dose range: 10 mJ-40 mJ; side length or diameter range of the exposure area: 20 μm-500 μm; exposure depth range: 0.3 μm-20 μm. 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 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 as described above, it is possible to fabricate extremely low-recessed lenses (angle <3°).

[0061] Before the thermal reflow process in step S6, the positive photoresist on the first surface of the wafer can be exposed to the corresponding number of exposures using an optical mask, depending on the layer requirements of the higher-order concave lens. The area formed by each exposure partially overlaps with the first exposure area and is deeper than the first exposure area. Except for the first exposure area, the areas formed by each subsequent exposure may partially overlap or not overlap with the areas formed by other exposure processes.

[0062] The above-described manufacturing process enables the individual or batch production of high-order ultra-low concave lenses. Based on this, using the high-order ultra-low concave lens as a hard template, imprinting adhesive is coated on the corresponding wafer surface, and the high-order ultra-low convex lens is fabricated using nanoimprinting technology. Finally, the pattern is transferred onto the wafer using etching technology to complete the fabrication of the high-order ultra-low convex lens.

[0063] The following is in conjunction with the appendix Figure 2 The method for fabricating a high-order lens according to this application is described in detail through a specific embodiment to facilitate further understanding of the technical solution of this application.

[0064] refer to Figure 2As shown, wafer 10 is first pretreated: it is cleaned and dried. Specifically, wafer 10 is first cleaned using the RCA cleaning process, and then placed on a high-temperature heating plate to thoroughly dry the surface moisture. Next, wafer 10 is placed in an oven for HMDS-hexamethyldisilazane (tackifier) ​​coating for 10-14 minutes at a temperature of 110-130°C.

[0065] Secondly, according to design requirements, positive photoresist is uniformly coated on the first surface of wafer 10. A uniform layer of positive photoresist 20 is applied to the top surface of wafer 10 using a spin coater. The positive photoresist is a low-expansion photoresist, such as the AZ5214, S6130, or AZ4620 series. The spin coater method involves uniformly coating the positive photoresist onto the top surface of wafer 10 using a spin coater, while preventing air bubbles from forming. After spin coating, the self-smoothing effect of the photoresist allows it to stand for a certain period of time to remove the ripples generated during spin coating. During coating, the spin coater speed is 3000 rpm, and the coating thickness is 5 μm.

[0066] Based on the required order of the higher-order concave lens and the required ROC (radius of curvature) of each order of the higher-order concave lens, photolithographic masks are fabricated. In this embodiment, for a fourth-order concave lens, four photolithographic masks are fabricated.

[0067] Next, stepped exposure is performed. A first mask is applied to the top surface of the positive photoresist 20. Then, the wafer 10 is placed in the center of the lithography machine tray, and contact lithography is used to expose the positive photoresist 20 to ultraviolet light, forming the first exposure area A. During ultraviolet exposure, the exposure conditions are set according to the required ROC (radius of curvature) of the concave lens. For example, the conditions for the first exposure 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 without development, a second mask is directly applied to the top surface of the positive photoresist 20. The wafer 10 is then placed in the center of the lithography machine tray, and contact lithography is used to perform stepped ultraviolet exposure on the positive photoresist 20, forming the second exposure region B. The second exposure region B partially overlaps with the first exposure region A. During ultraviolet exposure, the exposure conditions are set according to the required ROC (radius of curvature) of the concave lens. For example, the conditions for the second exposure are: exposure dose range: 10mJ-40mJ; side length or diameter range of the exposure region: 20μm-500μm; exposure depth range: 0.3μm-20μm.

[0069] After the second exposure, the second mask is removed, and without development, a third mask is directly applied to the top surface of the positive photoresist 20. The wafer 10 is then placed in the center of the lithography machine tray, and contact lithography is used to perform stepped ultraviolet exposure on the positive photoresist 20, forming the third exposure region C. The third exposure region C partially overlaps with the first exposure region A, and does not overlap with the second exposure region B, and is arranged parallel to it. During ultraviolet exposure, the exposure conditions are set according to the required ROC (radius of curvature) of the concave lens. For example, the conditions for the third exposure are: exposure dose range: 10mJ-40mJ; side length or diameter range of the exposure region: 20μm-500μm; exposure depth range: 0.3μm-20μm.

[0070] After the third exposure, the third mask is removed, and without development, a fourth mask is directly applied to the top surface of the positive photoresist 20. The wafer 10 is then placed in the center of the lithography machine tray, and contact lithography is used to perform stepped ultraviolet exposure on the positive photoresist 20, forming the fourth exposure region D. The fourth exposure region D partially overlaps with the first exposure region A, and also partially overlaps with both the second and third exposure regions B and C, and is perpendicular to both. During ultraviolet exposure, the exposure conditions are set according to the required ROC (radius of curvature) of the concave lens. For example, the conditions for the fourth exposure are: exposure dose range: 10mJ-40mJ; side length or diameter range of the exposure region: 20μm-500μm; exposure depth range: 0.3μm-20μm.

[0071] Then, the wafer 10 with positive photoresist 20 is reflowed. The wafer 10 is placed in an oven, and the bottom surface of the wafer 10 is fully in contact with the heating plate of the oven for heating. After heating, the wafer 10 is removed and allowed to cool to room temperature. At this time, the positive photoresist forms a photoresist film, and the top surface of the photoresist film is a high-order ultra-low concavity photoresist ball lens.

[0072] After the stepped exposure step, there is no need for development. The molecular chains between the molecules of the positive photoresist are directly unchained after exposure, which creates 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 into the non-exposed area to form the designed high-order ultra-low concavity photoresist spherical lens.

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

[0074] Alternatively, the pattern of the high-order ultra-low concave lens fabricated above can be transferred using nanoimprint technology to create a high-order ultra-low convex lens.

[0075] Example 1:

[0076] Wafer 10 was cleaned and dried. First, wafer 10 was cleaned using the RCA cleaning process. After cleaning, wafer 10 was placed on a high-temperature heating plate to thoroughly dry the surface moisture. Then, wafer 10 was placed in an oven for HMDS-hexamethyldisilazane (tackifier) ​​coating for 12 minutes at 120°C.

[0077] According to design requirements, positive photoresist was uniformly coated on the first surface of wafer 10. A uniform layer of positive photoresist 20 was applied to the top surface of wafer 10 using a spin coater. The positive photoresist was AZ5214. The spin coater method involves uniformly coating the positive photoresist onto the top surface of wafer 10 using a spin coater, while preventing air bubbles from forming. After spin coating, the self-smoothing effect of the photoresist was utilized, and the coating was left to stand for 40 minutes to remove any ripples generated during spin coating. During coating, the spin coater speed was 3000 rpm, and the coating thickness was 2 micrometers.

[0078] A first mask is applied to the top surface of the positive photoresist 20. Then, the wafer 10 is placed in the center of the lithography machine tray, and contact lithography is used to expose the positive photoresist 20 to ultraviolet light, forming the 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] After removing the first mask and without development, a second mask is directly applied to the top surface of the positive photoresist 20. The wafer 10 is then placed in the center of the lithography machine tray, and contact lithography is used to perform stepped ultraviolet exposure on the positive photoresist 20 to form the second exposure area B. During ultraviolet exposure, the exposure dose is 15 mJ; the side length of the exposure area is 135 * 50 μm. 2 The exposure depth is 1μm.

[0080] The wafer 10 with positive photoresist 20 is reflowed. Wafer 10 is placed in an oven, ensuring the bottom surface of wafer 10 is in full contact with the oven heating plate. The oven temperature is set to 65°C and heated for 5 minutes. After heating, the oven temperature is increased to 95°C and heated for another 10 minutes. After heating, wafer 10 is removed and allowed to cool to room temperature. At this point, the positive photoresist forms a photoresist film, and the top surface of the photoresist film is a high-order concave spherical lens. The angle of the high-order ultra-low concave spherical lens is 3°.

[0081] A high-order ultra-low concave lens is transferred onto wafer 10 using a plasma etching process to form a wafer-level high-order ultra-low concave lens.

[0082] Example 2:

[0083] Wafer 10 was cleaned and dried. First, wafer 10 was cleaned using the RCA cleaning process. After cleaning, wafer 10 was placed on a high-temperature heating plate to thoroughly dry the surface moisture. Then, wafer 10 was placed in an oven for HMDS-hexamethyldisilazane (tackifier) ​​coating for 12 minutes at 120°C.

[0084] According to design requirements, positive photoresist was uniformly coated on the first surface of wafer 10. A uniform layer of positive photoresist 20 was applied to the top surface of wafer 10 using a spin coater. The positive photoresist was S6130. Spin coater uniformly applied the positive photoresist to the top surface of wafer 10 using a spin coater, while preventing air bubbles from forming. After spin coater application, the self-smoothing effect of the photoresist allowed the substrate to stand for 40 minutes to remove any ripples caused by the spin coater application. During the coating process, the spin coater speed was 2500 rpm, and the coating thickness was 3 micrometers.

[0085] A first mask is applied to the top surface of the positive photoresist 20. Then, the wafer 10 is placed in the center of the lithography machine tray, and contact lithography is used to expose the positive photoresist 20 to ultraviolet light, forming the 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] After removing the first mask and without development, a second mask is directly applied to the top surface of the positive photoresist 20. The wafer 10 is then placed in the center of the lithography machine tray, and contact lithography is used to perform stepped ultraviolet exposure on the positive photoresist 20 to form the second exposure area B. During ultraviolet exposure, the exposure dose is 10 mJ; the side length of the exposure area is 100 * 700 μm. 2 The exposure depth is 0.5μm.

[0087] The wafer 10 with positive photoresist 20 is reflowed. Wafer 10 is placed in an oven, ensuring the bottom surface of wafer 10 is in full contact with the oven heating plate. The oven temperature is set to 65°C and heated for 5 minutes. After heating, the oven temperature is increased to 95°C and heated for another 10 minutes. After heating, wafer 10 is removed and allowed to cool to room temperature. At this point, the positive photoresist forms a photoresist film, and the top surface of the photoresist film is a high-order concave spherical lens. The angle of the high-order ultra-low concave spherical lens is 1°.

[0088] A high-order ultra-low concave lens is transferred onto wafer 10 using a plasma etching process to form a wafer-level high-order ultra-low concave lens.

[0089] Example 3:

[0090] Wafer 10 was cleaned and dried. First, wafer 10 was cleaned using the RCA cleaning process. After cleaning, wafer 10 was placed on a high-temperature heating plate to thoroughly dry the surface moisture. Then, wafer 10 was placed in an oven for HMDS-hexamethyldisilazane (tackifier) ​​coating for 12 minutes at 120°C.

[0091] According to design requirements, positive photoresist was uniformly coated on the first surface of wafer 10. A uniform layer of positive photoresist 20 was applied to the top surface of wafer 10 using a spin coater. The positive photoresist was AZ4620. Spin coater method refers to uniformly applying positive photoresist to the top surface of wafer 10 using a spin coater, while preventing the formation of air bubbles in the photoresist. After spin coater application, the self-smoothing effect of the photoresist was utilized to remove the ripples generated during spin coater application by allowing the coating to stand for 40 minutes. During coating, the spin coater speed was 3000 rpm, and the coating thickness was 6 micrometers.

[0092] A first mask is applied to the top surface of the positive photoresist 20. Then, the wafer 10 is placed in the center of the lithography machine tray, and contact lithography is used to expose the positive photoresist 20 to ultraviolet light, forming the 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] After removing the first mask and without development, a second mask is directly applied to the top surface of the positive photoresist 20. The wafer 10 is then placed in the center of the lithography machine tray, and contact lithography is used to perform stepped ultraviolet exposure on the positive photoresist 20 to form the second exposure region B. During ultraviolet exposure, the exposure dose is 20 mJ; the side length of the exposure region is 300 * 100 μm. 2 The exposure depth is 3μm.

[0094] The wafer 10 with positive photoresist 20 is reflowed. Wafer 10 is placed in an oven, ensuring the bottom surface of wafer 10 is in full contact with the oven heating plate. The oven temperature is set to 65°C and heated for 5 minutes. After heating, the oven temperature is increased to 95°C and heated for another 10 minutes. After heating, wafer 10 is removed and allowed to cool to room temperature. At this point, the positive photoresist forms a photoresist film, and the top surface of the photoresist film is a high-order concave spherical lens. The angle of the high-order ultra-low concave spherical lens is 4°.

[0095] A high-order ultra-low concave lens is transferred onto wafer 10 using a plasma etching process to form a wafer-level high-order ultra-low concave lens.

[0096] Example 4:

[0097] Example 4 differs from Example 3 only in the exposure conditions. During the first exposure, the exposure dose was 60 mJ; the side length of the exposed area was 700*700 μm. 2The exposure depth was 3 μm. During the second exposure, the exposure dose was 60 mJ; the side length of the exposed area was 200 x 900 μm. 2 The exposure depth is 5μm.

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

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

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

[0101] The high-order lens fabrication method and high-order lens of the present invention can form an extremely low concave lens (angle < 3°) under conditions without high expansion positive photoresist, such as AZ5214 and S6130 series, by controlling the exposure dose, exposure depth and the performance selection of positive photoresist. Furthermore, an extremely low convex lens (angle < 3°) can be fabricated by pattern transfer through nanoimprinting technology and etching technology.

[0102] It will be apparent to those skilled in the art that the present 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 its spirit or essential characteristics. Therefore, the embodiments should be considered in all respects as exemplary and non-limiting, and the scope of the invention is defined by the appended claims rather than the foregoing description. Thus, all variations falling within the meaning and scope of equivalents of the claims are intended to be included within the present invention. No reference numerals in the claims should be construed as limiting the scope of the claims.

[0103] Furthermore, it should be understood that although this specification describes embodiments, not every embodiment contains only one independent technical solution. This narrative style is merely for clarity. Those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments 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; A positive photoresist is homogenized on the first surface of the wafer; The first mask is used to perform a first exposure treatment on the positive photoresist on the first surface of the wafer to form a first exposure area; A second mask is used to perform a second exposure process on the positive photoresist on the first surface of the wafer to form a second exposure area, which partially overlaps with the first exposure area; After the stepped exposure step is completed, there is no need for development. The molecular chains between the molecules of the positive photoresist are unchained after exposure, which creates 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 towards the non-exposed area to form a high-order concave photoresist spherical lens. The high-order concave lens is transferred onto the wafer using 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 the spin coating step of positive photoresist on the first surface of the wafer, the method further includes: The steps for preprocessing wafers.

3. The method for manufacturing a high-order lens according to claim 2, characterized in that, Preprocessing of the wafer includes: Clean and dry the wafer; The wafer is placed in an oven for hexamethyldisilazane coating; The coating time is 10-14 minutes, and the oven temperature is 110℃-130℃.

4. The method for manufacturing a high-order lens according to claim 1, characterized in that, Based on the actual size requirements of the high-order concave lens, a corresponding optical mask is fabricated, wherein the optical mask includes at least 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 for the first exposure process are: Exposure dose range: 10mJ-40mJ; The side length or diameter range of the exposure area is 20μm-500μm; Exposure depth range: 0.3μm-20μm; and / or, The conditions for the second exposure process are: Exposure dose range: 10mJ-40mJ; The side length or diameter range of the exposure area is 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 hot reflow process, the positive photoresist on the first surface of the wafer can be exposed to the corresponding number of exposures according to the layer requirements of the high-order concave lens.

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

9. The method for manufacturing a high-order lens according to claim 1, characterized in that, Using the high-order concave lens as a hard template, an imprinting adhesive is coated on the corresponding wafer surface, and the high-order convex lens is fabricated using nanoimprinting technology. The pattern is then transferred onto the wafer using etching technology.

10. A high-order lens manufactured by a method for manufacturing a high-order lens as described in any one of claims 1-9.

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