Manufacturing method of micro-lens array
Through laser processing, a silicon -pores are formed and the use of optical UV glue to form a microscope array, which solves the problem of skewers in parallel layout in the existing technology, and reduces the cost of production and improves optical performance.
Patent Information
- Application Number
- CN202411624961.X
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-11-14
- Publication Date
- 2025-01-28
AI Technical Summary
The existing microlens arrays have crosstalk problems when they are arranged in parallel, and the photoresist materials used in traditional manufacturing methods have poor optical performance and high cost.
The laser processing technology is used to form a hole on the silicon wafer, and the liquid optical UV glue is dripped into the hole, and the microscope is formed by the gravity and the surface tension of the liquid. Then the ultraviolet light is used to solidify the optical UV gel to form a microscope array.
The production of non -birch -free microscopy arrays is achieved, simplifying the production process, reducing costs, and improving the optical properties of the microscope array.
Smart Images
Figure CN119375992A_ABST
Abstract
Description
Technical Field
[0001] The invention relates to the fields of semiconductor chips, integrated circuits and micro-nano processing, and in particular to a through silicon via method and a microlens array structure manufacturing technology. Background Art
[0002] Through Silicon Via technology, referred to as TSV (Through Silicon Via) technology, is to create vertical conductions between chips and wafers, and to interconnect chips through Z-direction through holes.
[0003] Through-silicon-via technology enables chips to have the highest density in three-dimensional integrated stacking, the shortest interconnection lines between chips, the smallest overall dimensions, and excellent anti-interference performance.
[0004] A microlens array is a regularly arranged lens array with a light aperture of micrometer or nanometer level. The microlens array units are small in size and tightly arranged, and can realize functions such as laser shaping, 3D imaging, beam focusing, and wavefront sensing.
[0005] Laser has the advantages of strong coherence and high brightness. By using this advantage, the laser can be focused to a point through a lens. The focus has high energy and the through hole can be achieved through the photothermal effect.
[0006] Optical UV glue has the advantages of high light transmittance, high adhesion, high light transmittance, oxidation resistance, water resistance, frost resistance, good high temperature resistance, safety, hygiene and non-toxicity, and has a plastic structure. It can be cured under ultraviolet light and cures quickly.
[0007] The main methods for making microlenses include photoresist melting technology, reactive ion beam etching, femtosecond laser direct writing technology, etc., and photoresist materials are needed. Compared with optical UV glue, the optical properties of photoresist materials themselves are poor and the cost is high. In addition, the produced microlens arrays all have the problem of crosstalk. The spacing between microlenses of the present invention effectively solves this problem. Summary of the invention
[0008] In view of the defects existing in the prior art, the purpose of the present invention is to achieve the above purpose, and the technical solution adopted by the present invention is: The present invention provides a system and method for laser processing of through silicon vias, which can realize through silicon vias efficiently and quickly, and has a simple structure and convenient operation. At the same time, in order to solve the problem of crosstalk in parallel microlens arrays, the purpose of the present invention is to provide a simple and effective microlens array structure to solve the above technical problems.
[0009] In order to achieve the above object, the present invention adopts the following technical solutions: A laser through-hole technology method includes processing a silicon wafer to obtain a silicon through-hole; dripping liquid optical UV glue on the processed silicon through-hole, and waiting for the liquid optical UV glue to form a lens under the action of gravity and liquid surface tension, and using ultraviolet light to irradiate the liquid optical UV glue to solidify it, so as to realize the method for manufacturing a microlens array.
[0010] The steps specifically include: A method for forming through-silicon vias using laser burning, wherein the system includes the following instruments: a nanosecond laser, a lens, and a vacuum box. In the present invention, the laser etching system is, in sequence: a nanosecond laser, a lens, and a vacuum box. Install them in sequence along the propagation direction of the nanosecond pulse laser light source, and place the sample at the focal position of the lens. A method for forming a microlens using optical UV glue, step one: clean and dry the sample. Step two: use a syringe to drop liquid optical UV glue into the lens. Step three: use a high-power ultraviolet light source to irradiate the optical UV glue to solidify it. The specific steps are as follows: Step 1: Place the sample at the focal length position in the vacuum box; Step 2: evacuate the vacuum box. The vacuum box needs to be evacuated to effectively reduce the damage range of the sample. Preferably, the selected sample material is a silicon wafer. Silicon has a low transmittance in the visible light band, but is transparent in the terahertz band, and can achieve filtering and frequency selection. Step 3: Clean the polished silicon wafer and blow dry or dry it with nitrogen; Step 4: Place the silicon wafer at the sample position and the sample stage at the focal position of the vacuum box, wherein the thickness of the silicon wafer (i.e., the through-hole depth) is 1 mm; Step 5: Use nanosecond laser to emit pulse light to hit the silicon wafer, and the number of pulses is enough to form a through-wound on the silicon wafer, thus realizing a through-silicon via; Step 6: Use the translation stage to move a distance of 100 microns to drill n rows and n columns of holes, the holes are arranged in an n*n square, and the thickness of the silicon wafer (i.e., the depth of the through hole) is 1 mm; Step 7: Use a syringe to drop liquid optical UV glue into the above through-holes. Due to the surface tension and gravity of the liquid, a microlens is formed. Let it stand for 5 minutes. Step eight, using a high-power ultraviolet light source to solidify the liquid optical UV glue.
[0011] Nanosecond lasers emit pulsed light.
[0012] The function of the lens is to focus the laser.
[0013] The vacuum box is custom made and made of glass.
[0014] Optical UV glue can be used as the main raw material for microlens arrays.
[0015] The diameter of the silicon hole is 100 microns and the thickness of the silicon wafer (i.e. the depth of the through hole) is 1 mm.
[0016] The refractive index of optical UV glue is 1.46.
[0017] Compared with the prior art, the advantages of the present invention are: (1) The present invention has a simple structure and a convenient manufacturing process; (2) The present invention can effectively save economic costs. The raw materials silicon wafers and optical UV adhesives are cheap, thus greatly saving economic costs; (3) The microlenses of the present invention have a certain spacing between them, which effectively improves the problem of large crosstalk in the microlens array and has a significant anti-crosstalk effect. BRIEF DESCRIPTION OF THE DRAWINGS
[0018] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.
[0019] Figure 1 It is a flow chart of the steps of the present invention.
[0020] Figure 2 Schematic diagram of the overall structure of the laser via system in the present invention.
[0021] Figure 3 The schematic diagram of the silicon wafer after perforation is shown as an example.
[0022] Figure 4 Demonstration of a microlens array that is cured after optical UV glue is dripped into a silicon wafer after perforation Figure 5 The schematic diagram of the hole shape after the through hole of this embodiment is exemplarily shown.
[0023] Figure 6 The schematic diagram after the optical UV glue is dripped into this embodiment is exemplarily shown.
[0024] Figure 7 This is a simulated light field diagram of the micro-optical device of the present invention, at a position of 300 microns.
[0025] Figure 8 This is a simulated light field diagram of the micro-optical device of the present invention, and the position is the focus.
[0026] Fig. 9 This is a simulated light field diagram of the micro-optical device of the present invention, at a position of 2 mm. DETAILED DESCRIPTION
[0027] In order to make the purpose, technical scheme and advantages of the embodiments of the present application clearer, the technical scheme in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of this application. The embodiments of the present invention are further described in detail below in conjunction with the drawings.
[0028] See also Figure 1 The present invention provides a method for preparing a three-dimensional microlens array, wherein Figure 2 The system structure of laser damage is shown, where 2-1 is a nanosecond laser, 2-2 is a vacuum box, and 2-3 is a sample. The steps for preparing a through hole are steps 1 to 4: Step 1: Clean and dry the sample and place it at the focal length in the vacuum box; Step 2: Evacuate the vacuum box to -98 KPa; Step 3: Use pulsed light with an energy of 0.35 joules to emit pulses until a through hole is achieved; Step 4: Use the translation stage to move the position of the vacuum box so that the distance between two adjacent holes is 100 microns.
[0029] The sample used for processing the microlens array base is metal such as silicon, nickel, germanium, etc., and silicon is preferred in this embodiment.
[0030] Among them, the wavelength of the pulse light emitted by the nanosecond laser is 532 nanometers.
[0031] The pulse energy was adjusted to 0.35 joules.
[0032] The through hole described in step three is measured to have a diameter of 100 microns.
[0033] Please refer to the obtained array through-hole structure Figure 3 .
[0034] The microlens array to be prepared in this application is as follows Figure 4 As shown, 4-1 is the silicon wafer; 4-2 is the microlens array, and its detailed structural diagram can be found in Figure 5 .
[0035] Figure 3 The microlens is made by using optical UV glue. The specific implementation of the microlens array is as follows: Step 5: Use a syringe to drop liquid optical UV glue into the above-mentioned through hole and let it stand. Microlenses are formed due to the surface tension of the liquid and gravity.
[0036] Step 6: Use a high-power ultraviolet light source to solidify the liquid optical UV glue.
[0037] See also Figure 4 The figure shows a detailed structural diagram of one row of through silicon vias of the present invention. Figure 5 The figure shows a detailed structural diagram of one column after the UV glue of the present invention is cured. Figure 6 , 7 , 8 are light field simulation diagrams at 300 microns, focus, and 2 mm respectively, simulated by the simulation software, where the lens diameter (i.e., through-hole diameter) is 100 microns, the array period is 200 microns, and the curvature radius of the microlens is 300 microns.
[0038] To calculate the focal length of a singlet lens, we will use the lens formula: , f is the focal length of the lens; R is the radius of curvature of the sphere; is the refractive index of the lens material; is the refractive index of the surrounding medium (the lens is in air, =1). The parameters of the lens are as follows: lens diameter D = 100 microns, array period 200 microns, lens curvature radius R = 300 microns, lens thickness d = 1 mm = 1000 microns, refractive index n = 1.46. The focal length is calculated to be: f = 652.17. Use simulation software for simulation, such as Figure 8 As shown in the figure, the focal length of the microlens array measured by the software is 651 microns, which is basically consistent with the conclusion drawn by calculation, with an error of only 0.179%.
[0039] In summary, the preparation method in this application uses laser perforation technology and the characteristics of optical UV glue to propose a new method for making a microlens array, and successfully simulates it to obtain a new type of microlens array without crosstalk. Please refer to Fig. 9 The light field simulation diagram of the present invention is shown, and the light field diagram in the figure shows that there is no crosstalk in the light field at this distance. Firstly, the above method is simple to operate, low in cost, can quickly produce a microlens array, and has high efficiency, which solves the problem of large crosstalk in the existing microlens array.
[0040] The above description is only a specific implementation of the present application, so that those skilled in the art can understand or implement the present application. Various modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the present application. Therefore, the present application will not be limited to the embodiments shown herein, but will conform to the widest range consistent with the principles and novel features applied for herein.
Claims
1. A method for preparing a microlens array, characterized in that: The lens is made of optical UV glue, and other parts are made of silicon wafers. The method includes: Step 1: Processing a silicon wafer to obtain a through silicon via; Step 2: dripping liquid optical UV glue on the processed silicon through hole, and waiting for the liquid optical UV glue to form a lens under the action of gravity and liquid surface tension; Step 3, using ultraviolet light to irradiate the liquid optical UV glue to solidify it; A method for forming a through silicon via by laser ablation, wherein the system comprises the following instruments: a nanosecond laser, a lens, and a vacuum box.
2. A method for manufacturing a microlens array, characterized in that there is a spacing between lenses to prevent crosstalk. The material used to manufacture the microlens array has a silicon wafer as a substrate, and optical UV glue is used to form the main component of the microlens array.
3. The method according to claim 1, characterized in that: Step one includes: The system is built to perform through silicon vias. The system is composed of the following parts: lens, vacuum box, and sample stage according to the nanosecond laser and the direction of laser propagation. The sample stage is located inside the vacuum box, and there is a translation stage at the bottom of the vacuum box; the silicon wafer is placed on the sample stage, and the sample stage is placed inside the vacuum box.
4. The method according to claim 1, characterized in that The light emitted by the laser is pulsed light, and the laser drilling forms a through hole. The vacuum box needs to be evacuated. Preferably, the sample used is a silicon wafer, which needs to be placed in the vacuum box and located at the focus of the lens.
5. The method according to claim 8, characterized in that Silicon has a low transmittance in the visible light band, but is transparent in the terahertz band, and can perform filtering and frequency selection functions.
6. The method according to claim 1, comprising the steps of: Step 1: Place the sample at the focal length in the vacuum box. Step 2: Evacuate the vacuum box. Step 3: Use the laser to emit pulsed light, and the number of pulses is enough to cause penetrating damage to the sample, thus achieving through-silicon vias.
7. The method according to claim 8, wherein the selected silicon wafer thickness (i.e., through-hole depth) is 1 mm, and the laser is re-irradiated to form holes in n rows and n columns arranged in an n*n square. The method according to claim 13 , wherein the distance between two adjacent holes is 100 μm.
9. The method according to claim 15, characterized in that Optical UV glue is a material with high refractive index and good light transmittance.
10. The method according to claim 2, preferably, the material constituting the microlens array is optical UV glue; the steps include: Step 1: Clean and dry the sample. Step 2: Use a syringe to drop liquid optical UV glue into the lens, and the lens will be formed under the action of gravity and liquid surface tension. Step 3: Use a high-power ultraviolet light source to irradiate the optical UV glue to solidify it.