A double-layer nested random single-sided microlens array and its manufacturing method

Abstract

The invention relates to the technical field of semiconductor device manufacturing process, in particular to a double-layer nested random single-sided microlens array and a manufacturing method thereof; by forming wet etching starting depths of different heights, two sets of microlens arrays with significantly different vector heights and virtual focal points are processed, the two sets of microlenses are mutually nested to form a complete and continuous microlens array, randomness of different heights between the microlenses is introduced, the conditions for generating a small amount of interference lattices are destroyed, the interference lattices are eliminated, and a flat-top homogenized light spot with completely uniform light spot intensity is realized; and by utilizing the isotropic etching characteristics of the wet etching process, the microlens array can be processed without adjusting etching parameters during the etching process, the process is simple, and the cost is saved.

Description

Technical Field

[0001] The invention relates to the technical field of semiconductor device manufacturing process, in particular to a double-layer nested random single-sided microlens array and a manufacturing method thereof. Background Art

[0002] The random microlens array structure is an optical structure widely used for laser beam homogenization. It eliminates the lattice generated by laser interference through a randomly arranged microlens array to achieve spot homogenization. However, the intensity distribution of the light spot after homogenization by the microlens array arranged completely randomly on the same plane will show a Gaussian distribution, and the intensity is uneven. In order to achieve a uniform flat-top distribution of the light spot intensity after homogenization, the microlens array needs to maintain a limited randomness that is close to a regular arrangement. However, under this limited randomness, a small amount of interference lattices is difficult to avoid, which affects the homogenization effect of the light spot.

[0003] The Chinese invention patent with application number "201980007680.0" and name "Diffuser Plate and Optical Device" adopts a double-sided microlens array homogenization scheme to eliminate a small amount of interference lattices; by manufacturing random microlens arrays on both sides of the substrate, the interference lattices are completely eliminated, and a flat-top distributed homogenized light spot is achieved. This method requires photolithography and dry etching on both sides of the substrate to process the microlens array structure. For the single-sided microlens array structure, the starting depth of dry etching in this scheme is on the same plane, and the microlens array has no obvious randomness in the height of the microlens virtual focus, and the generation of interference lattices cannot be avoided. Dry etching is anisotropic etching, so photolithography needs to use grayscale lithography that can manufacture continuous surface types, and use complex processes such as grayscale exposure. The etching parameters also need to be continuously adjusted during the dry etching process, and the process is complicated. Summary of the invention

[0004] In view of the problem that the interference lattice generated by the microlens array cannot be avoided, the present invention proposes a double-layer nested random single-sided microlens array and a manufacturing method thereof; by randomly dividing the random microlens array into two groups of microlens arrays, firstly photolithographing the vertices of one group of microlens arrays and performing dry etching, then photolithographing the vertices of the other group of microlens arrays, and finally performing wet etching, the two groups of microholes have different wet etching starting heights, so that the microlens array has not only the randomness of the two dimensions of planar arrangement, but also the randomness of the dimension of virtual focus height, which fully reduces the probability of interference of sub-beams generated by the light beam passing through the microlens array, and avoids the appearance of interference lattice bright spots.

[0005] The specific implementation contents of the present invention are as follows:

[0006] A double-layer nested random single-sided microlens array comprises a substrate; the double-layer nested random single-sided microlens array is located in the substrate;

[0007] The double-layer nested random single-sided microlens array comprises a first single-sided microlens array and a second single-sided microlens array nested in each other;

[0008] The number of vertices of the first single-sided microlens array is the same as that of the second single-sided microlens array, and the vector height of the first single-sided microlens array is different from that of the second single-sided microlens array.

[0009] In order to better implement the present invention, further, the substrate is a quartz substrate or a glass substrate.

[0010] In order to better implement the present invention, further, the first single-sided microlens array and the second single-sided microlens array are single-sided concave lens arrays.

[0011] Based on the double-layer nested random single-sided microlens array proposed above, in order to better realize the present invention, further, a manufacturing method of a double-layer nested random single-sided microlens array is proposed, firstly, the single-sided microlens array is randomly divided into a first single-sided microlens array and a second single-sided microlens array with an equal number of microholes, and a photolithography mask and an overlay mask are designed; secondly, the microholes of the first single-sided microlens array are used as a mask pattern for the first photolithography to perform a first photolithography, and dry etching is performed to obtain a first microhole array; then, the microholes of the second single-sided microlens array are used as a mask pattern for overlay to perform a second photolithography to obtain a second microhole array; finally, wet etching is performed using the first microhole array and the second microhole array with different depths as the starting depths of wet etching to obtain a random microlens array with a double-layer nested structure.

[0012] In order to better implement the present invention, further, the manufacturing method of the double-layer nested random single-sided microlens array specifically includes the following steps:

[0013] Step S1: randomly dividing the single-sided microlens array into two groups of single-sided microlens arrays with equal numbers of microholes, and manufacturing a photolithography mask and an overlay mask;

[0014] Step S2: performing first photolithography using the microholes of one group of single-sided microlens arrays as a mask pattern for first photolithography, and performing dry etching to transfer the mask pattern of the first photolithography to the substrate to obtain a first microhole array;

[0015] Step S3: using the microholes of another group of single-sided microlens arrays as an overlay mask pattern for a second photolithography, and transferring the overlay mask pattern to the chrome film layer to obtain a second microhole array;

[0016] Step S4: performing wet etching with the first microhole array and the second microhole array having different depths as the starting depths of wet etching to obtain a random microlens array with a double-layer nested structure.

[0017] In order to better implement the present invention, further, the step S1 specifically includes the following steps:

[0018] Step S11: using randomly arranged array micropores as a mask image;

[0019] Step S12: randomly dividing the single-sided microlens array into two groups of single-sided microlens arrays with equal numbers of microholes, and manufacturing a photolithography mask and an overlay mask.

[0020] In order to better implement the present invention, further, the step S2 specifically includes the following steps:

[0021] Step S21: a chromium film layer on one side of the double-sided polished substrate is used as a masking layer for wet etching;

[0022] Step S22: Spin-coating photoresist on the surface of the chrome film layer to form a first photoresist layer, performing first photolithography and developing using the microholes of one group of the single-sided microlens arrays as a mask pattern for first photolithography, and transferring the mask pattern for first photolithography to the first photoresist layer;

[0023] Step S23: placing the substrate into a chromium removal solution to transfer the mask pattern of the first photolithography to the chromium film layer;

[0024] Step S24: etching the substrate using a dry etching process to transfer the mask pattern of the first photolithography to the substrate;

[0025] Step S25: removing the first photoresist layer to obtain a first microwell array.

[0026] In order to better implement the present invention, further, the step S3 specifically includes the following steps:

[0027] Step S31: Spin-coating photoresist on the surface of the chrome film layer to form a second photoresist layer, performing a second photolithography using the microholes of another group of single-sided microlens arrays as an overlay mask pattern, and transferring the overlay mask pattern to the second photolithography layer;

[0028] Step S32: placing the substrate into a chromium removal solution to transfer the overlay mask pattern to the chromium film layer;

[0029] Step S33: removing the second photoresist layer to obtain a second microwell array.

[0030] In order to better implement the present invention, further, the specific operation of step S4 is: first, the substrate is placed in an etching solution, and wet etching is performed with the first micropore array and the second micropore array having different depths as the starting depths of wet etching to obtain two groups of single-sided microlens arrays with different vector heights, and the two groups of single-sided microlens arrays with different vector heights are nested with each other to obtain a continuous random microlens array with a double-layer nested structure.

[0031] In order to better implement the present invention, further, the starting depth of the wet etching of the first microhole array is the bottom and sidewall of the cylindrical micropits formed on the substrate after dry etching;

[0032] The starting depth of the wet etching of the second microhole array is the surface of the substrate exposed after the overlay mask pattern is transferred to the chrome film layer.

[0033] In order to better implement the present invention, further, the mask pattern is randomly arranged square lattice array micropores or hexagonal lattice micropores.

[0034] The present invention has the following beneficial effects:

[0035] (1) The present invention forms wet etching starting depths of different heights to process two sets of microlens arrays with significantly different vector heights and virtual focal points, and nests the two sets of microlenses to form a complete and continuous microlens array, introduces randomness of different heights between microlenses, destroys the conditions for generating a small amount of interference lattices, eliminates the interference lattices, and realizes a flat-top homogenized light spot with completely uniform light spot intensity.

[0036] (2) The present invention utilizes the isotropic etching characteristics of the wet etching process. The microlens array can be processed without adjusting the etching parameters during the etching process, which simplifies the process and saves costs.

[0037] (3) The present invention breaks the regular arrangement of the microlens array, designs a randomly arranged microlens array layout, introduces randomness in two dimensions of the microlens array planar arrangement, and introduces randomness in the dimension of the height of the microlens virtual focus of the microlens array, thereby further suppressing the generation of interference lattices. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] Figure 1 This is a schematic structural diagram of the first spin coating of photoresist provided by the present invention.

[0039] Figure 2 This is a schematic diagram of the structure of the first photolithography provided by the present invention.

[0040] Figure 3 This is a schematic structural diagram of the first chromium film etching provided by the present invention.

[0041] Figure 4 This is a schematic diagram of the dry etching structure provided by the present invention.

[0042] Figure 5 This is a schematic structural diagram of the second spin coating of photoresist provided by the present invention.

[0043] Figure 6 This is a schematic structural diagram of the second photolithography provided by the present invention.

[0044] Figure 7 This is a schematic structural diagram of the second chromium film etching provided by the present invention.

[0045] Figure 8 A schematic diagram of the structure for removing the second photoresist layer provided by the present invention.

[0046] Fig. 9 This is a schematic diagram of the double-layer nested random single-sided microlens array structure provided by the present invention.

[0047] Among them, 1. substrate, 2. chrome film layer, 3. first photoresist layer, 4. second photoresist layer, 5. first microhole array, 6. second microhole array, 7. first single-sided microlens array, 8. second single-sided microlens array. DETAILED DESCRIPTION

[0048] In order to more clearly illustrate the technical solutions of the embodiments of 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. It should be understood that the described embodiments are only part of the embodiments of the present invention, not all of the embodiments, and therefore should not be regarded as limiting the scope of protection. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technical personnel in this field without making creative work are within the scope of protection of the present invention.

[0049] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "disposed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be an indirect connection through an intermediate medium, or it can be the internal communication of two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0050] Embodiment 1:

[0051] This embodiment provides a double-layer nested random single-sided microlens array, including a substrate 1, such as Fig. 9 As shown, the double-layer nested random single-sided microlens array is located in the substrate 1;

[0052] The double-layer nested random single-sided microlens array comprises a first single-sided microlens array 7 and a second single-sided microlens array 8 which are nested with each other;

[0053] The number of vertices of the first single-sided microlens array 7 is the same as the number of vertices of the second single-sided microlens array 8 , and the vector height of the first single-sided microlens array 7 is different from the vector height of the second single-sided microlens array 8 .

[0054] Working principle: In order to eliminate the interference lattice, this embodiment adopts a first single-sided microlens array 7 and a second single-sided microlens array 8 of different depths, which are nested with each other to form a double-layer nested random microlens array, introduce the randomness of different heights between the microlenses, destroy the conditions for generating a small amount of interference lattices, eliminate the interference lattice, and achieve a flat-top homogenized light spot with completely uniform light spot intensity.

[0055] Embodiment 2:

[0056] In this embodiment, based on the above-mentioned embodiment 1, the substrate 1 is set as a quartz substrate or a glass substrate.

[0057] Working principle: Microlens arrays are generally used for light beam homogenization, so a transparent substrate is selected in this embodiment. Wet etching process is generally used for etching inorganic non-metallic materials, so a quartz substrate or a glass substrate is selected in this embodiment.

[0058] The other parts of this embodiment are the same as those of the above-mentioned embodiment 1, and thus will not be described in detail.

[0059] Embodiment 3:

[0060] In this embodiment, based on any one of the above-mentioned embodiments 1 to 2, the first single-sided microlens array 7 and the second single-sided microlens array 8 are single-sided concave lens arrays.

[0061] Working principle: The microlens array structure of this embodiment is a single-sided microlens array, in which the microlenses are concave lenses, and the arrangement is a randomly arranged square or hexagonal grid tightly arranged. By manufacturing two groups of lenses with randomly distributed heights in the vector height and virtual focus height, the microlens array has the randomness of the virtual focus height in addition to the two dimensions of planar arrangement. The randomness of more dimensions fully reduces the probability of interference of the sub-beams generated by the light beam passing through the microlens array, avoiding the appearance of bright spots of the interference lattice.

[0062] The other parts of this embodiment are the same as any one of the above-mentioned embodiments 1-2, so they will not be repeated here.

[0063] Embodiment 4:

[0064] Based on any one of the above-mentioned embodiments 1 to 3, this embodiment proposes a method for manufacturing a double-layer nested random single-sided microlens array. First, the single-sided microlens array is randomly divided into a first single-sided microlens array 7 and a second single-sided microlens array 8 with an equal number of microholes, and a photolithography mask and an overlay mask are designed; secondly, the microholes of the first single-sided microlens array 7 are used as a mask pattern for the first photolithography to perform a first photolithography, and dry etching is performed to obtain a first microhole array 5; then, the microholes of the second single-sided microlens array 8 are used as a mask pattern for overlay to perform a second photolithography to obtain a second microhole array 6; finally, wet etching is performed using the first microhole array 5 and the second microhole array 6 with different depths as the starting depths of wet etching to obtain a random microlens array with a double-layer nested structure.

[0065] Working principle: In this embodiment, a set of closely arranged random microlens arrays is randomly divided into two groups of microlenses, and the vertices of one group of microlenses are first photoetched and dry-etched, and then the vertices of the other group of microlenses are photoetched, and finally wet-etched to manufacture a random microlens array with a double-layer nested structure. The microhole photolithography circular holes of the first single-sided microlens array 7 are dry-etched, and the microholes of the second single-sided microlens array 8 are not dry-etched, so that the two groups of microholes in the wet etching process have two different wet etching starting heights, and the two groups of lenses are manufactured to have two groups of randomly distributed heights in the vector height and virtual focus height, so that the microlens array has the randomness of the virtual focus height in addition to the randomness of the two dimensions of the planar arrangement. The two dimensions of the planar arrangement refer to the microlenses, and the randomness of the arrangement of the X-axis, i.e., left and right, and the Y-axis, i.e., up and down, in the plane of the substrate surface can be measured by the vertex of the microlens or the virtual focus position. The dimension of the virtual focus height refers to the dimension perpendicular to the substrate surface, which is equivalent to the Z axis. The randomness of this dimension is caused by the etching starting depths of different heights. The randomness of more dimensions reduces the probability of interference between sub-beams generated by the light beam passing through the microlens array, thus avoiding the appearance of bright spots of the interference lattice.

[0066] The other parts of this embodiment are the same as any one of the above-mentioned embodiments 1 to 3, so they will not be repeated here.

[0067] Embodiment 5:

[0068] This embodiment is described in detail in the form of steps based on any one of the above embodiments 1 to 4, and specifically includes the following steps.

[0069] Step S1: randomly divide the single-sided microlens array into two groups of first single-sided microlens array 7 and second single-sided microlens array 8 with equal numbers of microholes, and manufacture a photolithography mask and an overlay mask.

[0070] The step S1 specifically includes the following steps:

[0071] Step S11: using randomly arranged array micropores as a mask image;

[0072] Step S12: randomly divide the single-sided microlens array into two groups, a first single-sided microlens array 7 and a second single-sided microlens array 8, with the same number of microholes, to manufacture a photolithography mask and an overlay mask.

[0073] In this embodiment, the mask for photolithography and overlay is first designed. The mask pattern is a randomly arranged square or hexagonal grid array of microholes. 50% of the microholes are randomly selected as the mask pattern for the first photolithography, and the other 50% of the microholes are used as the overlay mask pattern. If the subsequent photolithography requires ultraviolet lithography, the photolithography and overlay mask plate is manufactured. The microhole will be used as the etching starting point in the subsequent wet etching process, and the microhole will be located at the vertex of each microlens in the final manufactured microlens array.

[0074] Step S2: performing first photolithography using the microholes of the first single-sided microlens array 7 as a mask pattern for first photolithography, and performing dry etching, transferring the mask pattern of the first photolithography to the substrate 1 to obtain a first microhole array 5.

[0075] The step S2 specifically includes the following steps:

[0076] Step S21: a chromium film layer 2 on one side of the double-sided polished substrate 1 is used as a masking layer for wet etching;

[0077] Step S22: Spin-coating photoresist on the surface of the chrome film layer 2 to form a first photoresist layer 3, performing first photolithography and developing using the microholes of the first single-sided microlens array 7 as a mask pattern for first photolithography, and transferring the mask pattern for first photolithography to the first photoresist layer 3;

[0078] Step S23: placing the substrate 1 in a chromium removal solution, and transferring the mask pattern of the first photolithography to the chromium film layer 2;

[0079] Step S24: etching the substrate 1 using a dry etching process to transfer the mask pattern of the first photolithography to the substrate 1;

[0080] Step S25: removing the first photoresist layer 3 to obtain a first microwell array 5.

[0081] like Figure 1 As shown in FIG. 1 , firstly, a chrome film layer 2 is plated on one side of a double-sided polished quartz substrate or a glass substrate as a mask layer for wet etching; secondly, a photoresist is spin-coated on the surface of the chrome film layer 2 on the chrome-plated side of the substrate 1 for the first photolithography, and the pattern of the photolithography mask is transferred to the first photoresist layer 3 through conventional exposure processes such as ultraviolet exposure and laser direct writing after development. Figure 2Then, the chromium film layer 2 carrying the photoresist pattern information is chemically reacted with the chromium removal liquid to transfer the pattern on the first photoresist layer 3 to the chromium film layer 2, as shown. Figure 3 As shown in FIG. 1 , the first chromium film etching is performed, and the quartz substrate or glass substrate at the pattern is exposed and no longer protected by the chromium film layer 2; then, the developed quartz substrate or glass substrate is etched using a dry etching process such as RIE or ICP, as shown in FIG. Figure 4 As shown, the pattern of the first photoresist layer 3 is transferred to the substrate 1 to form cylindrical micro-pits, namely the first micro-hole array 5. The depth of the micro-pits is equal to the etching depth. The etching depth in this embodiment is determined according to requirements, such as 1 micron. Finally, the remaining photoresist, namely the remaining first photoresist layer 3, is removed.

[0082] In this embodiment, the spin-coated photoresist can be a positive photoresist or a negative photoresist, and the same photolithographic pattern can be obtained through different layout designs. In this embodiment, a positive photoresist is selected because the layout of the positive photoresist is easier to draw in the processing of this structure, the mask is easier to manufacture, and the processing cost is lower.

[0083] In the exposure described in this embodiment, the exposure dose of the mask pattern is consistent during the exposure process, the exposed first photoresist layer 3 is completely exposed, and the photoresist at the pattern is completely removed after development, forming a two-dimensional pattern on the first photoresist layer 3. Grayscale lithography is to use grayscale lithography mask, that is, mask contact lithography or computer control of laser beam or electron beam dose to achieve complete exposure in some areas, while some areas of photoresist are partially exposed, thereby leaving a 3D contour morphology of the photoresist structure on the substrate. For the microlens array structure, its contour morphology can be controlled by controlling the dose distribution.

[0084] Step S3: performing a second photolithography using the microholes of the second single-sided microlens array 8 as an overlay mask pattern, and transferring the overlay mask pattern to the chrome film layer 2 to obtain a second microhole array 6 .

[0085] The step S3 specifically comprises the following steps:

[0086] Step S31: Spin-coating photoresist on the surface of the chrome film layer 2 to form a second photoresist layer 4, performing a second photolithography using the microholes of the second single-sided microlens array 8 as an overlay mask pattern, and transferring the overlay mask pattern to the second photoresist layer 4;

[0087] Step S32: placing the substrate 1 into a chromium removal solution to transfer the overlay mask pattern to the chromium film layer 2;

[0088] Step S33: removing the second photoresist layer 4 to obtain a second microwell array 6.

[0089] like Figure 5As shown, the surface of the chrome film layer 2 on the chrome-plated side of the substrate 1 is again spin-coated with photoresist to form a second photoresist layer 4 for a second photolithography, overlay exposure, and then development and other operations are performed, such as Figure 6 As shown, the pattern of the overlay mask is transferred to the second photoresist layer 4; Figure 7 As shown, the second chromium film etching is performed, and the substrate 1 is placed in the chromium removal solution again to transfer the photoresist pattern to the chromium film layer 2, as shown in FIG. Figure 8 As shown, the remaining photoresist, namely the second photoresist layer 4 , is finally removed to obtain a second microwell array 6 .

[0090] Step S4: wet etching is performed with the first microhole array 5 and the second microhole array 6 having different depths as the starting depths of wet etching to obtain a random microlens array with a double-layer nested structure.

[0091] The specific operation of step S4 is as follows: firstly, the substrate 1 is placed in an etching solution, and wet etching is performed with the first micropore array 5 and the second micropore array 6 having different depths as the starting depths of wet etching, so as to obtain a first single-sided microlens array 7 and a second single-sided microlens array 8 having different vector heights, which are nested with each other to obtain a continuous random microlens array with a double-layer nested structure.

[0092] The starting depth of the wet etching of the first micro-hole array 5 is the bottom and sidewall of the cylindrical micro-pits formed on the substrate 1 after dry etching;

[0093] The starting depth of the wet etching of the second microhole array 6 is the surface of the substrate 1 exposed after the overlay mask pattern is transferred to the chromium film layer 2 .

[0094] like Fig. 9 As shown, the substrate 1 is placed in an etching solution with silicon dioxide substrate etching function such as hydrofluoric acid for wet etching. The etching solution penetrates and corrodes the quartz substrate or glass substrate from the pattern micropores of the chromium film layer 2 to form a randomly distributed hexagonal or square microlens array structure, completing the preparation of the random microlens array. Since wet etching is isotropic etching, the etched microlenses are spherical concave lenses. By controlling the etching time, each microlens fully intersects with the edges of the surrounding microlenses to form a continuous surface microlens array structure;

[0095] Since the micro-holes of the first photolithography have a certain depth after dry etching, the micro-holes of the two photolithography have a difference in the starting depth of wet etching. The starting depth of the micro-holes of the first photolithography is the bottom and side wall of the small hole after dry etching the quartz substrate or glass substrate, and the starting depth of the micro-holes of the second photolithography is the surface of the quartz or glass substrate exposed after the pattern is transferred to the chromium film layer 2. This difference will cause the micro-lens array formed by wet etching to contain two sets of micro-lenses with significantly different vector heights, and the two sets of micro-lenses are nested with each other to form a complete and continuous micro-lens array.

[0096] Working principle: This embodiment first utilizes the isotropic etching characteristics of the wet etching process, and the microlens array can be processed without adjusting the etching parameters during the etching process. And through the first photolithography and dry etching, grayscale exposure is not required, and the photolithography pattern is a 2D plane pattern, so the small hole of dry etching is a cylindrical micro-pit, not a spherical surface. Dry etching is anisotropic etching, and the etching direction can only be perpendicular to the surface of the substrate 1. For the structure of cylindrical micro-pits, the area of ​​the etched substrate surface remains basically unchanged during the etching process, and there is no need to adjust the etching gas formula during the etching process. However, the microlens array processed by grayscale exposure is a 3D spherical surface. During the dry etching process of the microlens array, as the photoresist layer is etched, the exposed substrate surface area continues to increase, so it is necessary to continuously adjust the etching gas formula to ensure the etching speed, and the etching parameters are fixed. Then the cylindrical micro-pit is processed, and the depth of the bottom of the micro-pit is used as the wet etching starting depth of the first single-sided microlens array 7. The second photolithography process exposes a circular hole pattern on the surface of the substrate 1, and the exposed surface of the substrate 1 is used as the starting height of wet etching for the second single-sided microlens array. By forming wet etching starting depths of different heights, a microlens array can be processed to include two sets of microlenses with significantly different vector heights and virtual focal points. The two sets of microlenses are nested with each other to form a complete and continuous microlens array to avoid interference lattices. The process is relatively simple and cost-effective. The method to avoid the appearance of interference lattices in the homogenized light spot of the microlens is to break the regular arrangement of the microlens array, introduce randomness, and design a randomly arranged microlens array layout, which can introduce randomness in two dimensions of the planar arrangement of the microlens array. The process method of this embodiment further introduces randomness in the dimension of the height of the virtual focal point of the microlens of the microlens array, further suppressing the generation of interference lattices.

[0097] The other parts of this embodiment are the same as any one of the above-mentioned embodiments 1 to 4, so they are not repeated here.

[0098] The above description is only a preferred embodiment of the present invention and does not limit the present invention in any form. Any simple modification or equivalent change made to the above embodiment based on the technical essence of the present invention shall fall within the protection scope of the present invention.

Claims

1. A method for manufacturing a double-layer nested random single-sided microlens array, characterized in that: Firstly, the single-sided microlens array is randomly divided into a first single-sided microlens array (7) and a second single-sided microlens array (8) with the same number of microholes, and a photolithography mask and an overlay mask are designed; secondly, the microholes of the first single-sided microlens array (7) are used as a mask pattern for the first photolithography to perform a first photolithography, and dry etching is performed to obtain a first microhole array (5); then, the microholes of the second single-sided microlens array (8) are used as a mask pattern for overlay etching to perform a second photolithography to obtain a second microhole array (6); finally, wet etching is performed using the first microhole array (5) and the second microhole array (6) with different depths as the starting depths of wet etching to obtain a random microlens array with a double-layer nested structure; The manufacturing method of the double-layer nested random single-sided microlens array specifically comprises the following steps: Step S1: randomly dividing the single-sided microlens array into two groups of a first single-sided microlens array (7) and a second single-sided microlens array (8) with equal numbers of microholes, and manufacturing a photolithography mask and an overlay mask; Step S2: performing a first photolithography using the microholes of the first single-sided microlens array (7) as a mask pattern for a first photolithography, and performing dry etching, transferring the mask pattern of the first photolithography to the substrate (1), thereby obtaining a first microhole array (5); Step S3: using the microholes of the second single-sided microlens array (8) as an overlay mask pattern for a second photolithography, and transferring the overlay mask pattern to the chrome film layer (2) to obtain a second microhole array (6); Step S4: wet etching is performed using the first microhole array (5) and the second microhole array (6) having different depths as the starting depths of wet etching to obtain a random microlens array having a double-layer nested structure.

2. The method for manufacturing a double-layer nested random single-sided microlens array according to claim 1, characterized in that: The step S1 specifically includes the following steps: Step S11: using randomly arranged array micropores as a mask image; Step S12: randomly dividing the single-sided microlens array into two groups of a first single-sided microlens array (7) and a second single-sided microlens array (8) with an equal number of microholes, and manufacturing a photolithography mask and an overlay mask.

3. The method for manufacturing a double-layer nested random single-sided microlens array according to claim 1, characterized in that: The step S2 specifically includes the following steps: Step S21: a chromium film layer (2) is used as a masking layer for wet etching on one side of the double-sided polished substrate (1); Step S22: Spin-coating a photoresist on the surface of the chrome film layer (2) to form a first photoresist layer (3), performing a first photolithography using the microholes of the first single-sided microlens array (7) as a mask pattern for a first photolithography and developing the pattern, and transferring the mask pattern for the first photolithography to the first photoresist layer (3); Step S23: placing the substrate (1) into a chromium removal solution, and transferring the mask pattern of the first photolithography to the chromium film layer (2); Step S24: etching the substrate (1) using a dry etching process to transfer the mask pattern of the first photolithography to the substrate (1); Step S25: removing the first photoresist layer (3) to obtain a first microwell array (5).

4. The method for manufacturing a double-layer nested random single-sided microlens array according to claim 3, characterized in that: The step S3 specifically comprises the following steps: Step S31: Spin-coating a photoresist on the surface of the chrome film layer (2) to form a second photoresist layer (4), performing a second photolithography using the microholes of the second single-sided microlens array (8) as an overlay mask pattern, and transferring the overlay mask pattern to the second photoresist layer (4); Step S32: placing the substrate (1) into a chromium removal solution, and transferring the overlay mask pattern to the chromium film layer (2); Step S33: removing the second photoresist layer (4) to obtain a second microwell array (6).

5. The method for manufacturing a double-layer nested random single-sided microlens array according to claim 4, characterized in that: The specific operation of step S4 is as follows: firstly, the substrate (1) is placed in an etching solution, and wet etching is performed using the first micropore array (5) and the second micropore array (6) having different depths as the starting depths of wet etching to obtain a first single-sided microlens array (7) and a second single-sided microlens array (8) having different vector heights, which are nested with each other to obtain a continuous random microlens array with a double-layer nested structure.

6. The method for manufacturing a double-layer nested random single-sided microlens array according to claim 5, characterized in that: The starting depth of the wet etching of the first microhole array (5) is the bottom and sidewall of the cylindrical micropits formed on the substrate (1) after dry etching; The starting depth of the wet etching of the second microhole array (6) is the surface of the substrate (1) exposed after the overlay mask pattern is transferred to the chromium film layer (2).

7. A method for manufacturing a double-layer nested random single-sided microlens array according to any one of claims 1 to 6, characterized in that: The mask pattern is randomly arranged square lattice array microholes or hexagonal lattice microholes.

8. The method for manufacturing a double-layer nested random single-sided microlens array according to claim 1, characterized in that: A random microlens array with a double-layer nested structure comprises a substrate (1); the double-layer nested random single-sided microlens array is located inside the substrate (1); The double-layer nested random single-sided microlens array comprises a first single-sided microlens array (7) and a second single-sided microlens array (8) which are nested with each other; The number of vertices of the first single-sided microlens array (7) is the same as the number of vertices of the second single-sided microlens array (8), and the vector height of the first single-sided microlens array (7) is different from the vector height of the second single-sided microlens array (8).

9. The method for manufacturing a double-layer nested random single-sided microlens array according to claim 1, characterized in that: The substrate (1) is a quartz substrate or a glass substrate.

10. The method for manufacturing a double-layer nested random single-sided microlens array according to claim 1, characterized in that: The first single-sided micro-lens array (7) and the second single-sided micro-lens array (8) are single-sided concave lens arrays.

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