Special glass microstructure etching method and etching film layer

Abstract

The invention belongs to a special glass microstructure etching method in the technical field of special glass, and relates to a film layer at the same time. Setting design parameters: minimum line width d and etching depth h, and calculating a viscosity target value: V = 85 * e (-0.12 * d) + 38 * ln (h) = XcP; a film layer is coated on the surface of glass to be etched, a peelable layer (1), a corrosion resistance control layer (2) and an interface bonding layer (3) are sequentially coated, the peelable layer (1) is made of low polyurethane, the viscosity value V1 of the peelable layer (1) is 0.25 V, the corrosion resistance control layer (2) is made of acrylate copolymer, the viscosity value V2 of the corrosion resistance control layer (2) is V + / -3%, and the interface bonding layer (3) is made of epoxy modified organic silicon resin, and the viscosity value V3 of the interface bonding layer (3) is 1.8 V; the special glass microstructure etching method provided by the invention has simple steps, and can inhibit lateral permeation, eliminate film layer residues, stabilize etching depth and improve product processing quality when being used in cooperation with the etching method in the special glass etching process.

Description

Technical Field

[0001] This invention belongs to the field of special glass technology, and more specifically, relates to a method for etching the microstructure of special glass. Background Technology

[0002] In the field of special glass micromachining, chemical etching combined with laser stripping is a common process for realizing three-dimensional microstructures. Traditional methods (such as CN113582032A) use a single-layer acid-resistant film to cover the glass surface, and then form a patterned window by ultraviolet laser ablation followed by single-sided etching. However, this process has three major bottleneck problems: 1. Uncontrolled etching precision: Due to the unstable bonding strength between the acid-resistant film and the glass interface, the etching solution is prone to capillary penetration along the edge of the film. When the etching depth is >20μm, lateral erosion leads to a linewidth expansion rate as high as 15-25% (see data from JP2020157782A example), which cannot meet the ±2μm tolerance requirements of precision devices such as microlens arrays. 2. Film peeling defects: Existing technologies use a fixed adhesive film layer (usually 200±50cP). High-viscosity films (>300cP) produce carbonized residues after laser ablation, with a peeling residue rate of over 12%; low-viscosity films (<100cP) are prone to localized film peeling during the etching process, resulting in etching leaks. 3. Difficulty in controlling height difference: The step height of the 3D pattern is controlled by a single variable, etching time, without considering the nonlinear effect of viscosity on the etching rate. Experimental results show ( Figure 1 Under the same etching conditions, the 150cP viscous film exhibited an etching depth deviation of +18.7% compared to the 250cP film, resulting in a microstructure uniformity of less than 70%. Although CN114180884A attempted to optimize laser parameters to improve film stripping quality, it did not reveal the intrinsic relationship between the acid-resistant film's viscousness and etching depth; while US2022037132A1 proposed a multilayer film structure, it did not establish a viscous gradient control model. The industry urgently needs to develop a viscous control method that can dynamically match pattern size and etching depth to solve core defects such as edge collapse and uneven depth. Note: Traditional mechanical dicing edge collapse >20μm; chemical etching mask method trench depth deviation ±25μm; laser cutting heat-affected zone >8μm; existing laser-etching combined processes lack a line spacing / etching concentration synergistic model, leading to nonlinear failure of trench depth (fluctuation ±15μm) and serration residue (>5μm).

[0003] In summary, the shortcomings of the existing solutions are as follows: 1. Uncontrolled capillary penetration of etching solution: The fixed viscosity of the acid-resistant film interface causes the etching solution to seep along the edge of the pattern, resulting in a 25% expansion of the 50μm linewidth structure; 2. High defect rate of film peeling: The laser parameters are not matched with the film viscosity, resulting in a residual rate of >12% when >300cP and a peeling rate of >15% when <100cP; 3. Poor consistency of step height: Viscosity fluctuations cause nonlinear changes in the etching rate, with a deviation of ±18.7% in the 50μm target depth.

[0004] The existing technology does not address the technical issues and solutions of this application. Summary of the Invention

[0005] The technical problem to be solved by the present invention is to provide a special glass microstructure etching method that is simple in steps, can suppress lateral penetration, eliminate film residue, stabilize etching depth, and improve product processing quality during the special glass etching process, in order to overcome the shortcomings of the prior art.

[0006] To solve the above-mentioned technical problems, the technical solution adopted by the present invention is as follows: This invention relates to a method for etching microstructures in special glass. S1. Set design parameters: minimum linewidth d, etching depth h, calculate target viscosity value: V=85·e (-0.12×d) +38·ln (h) =XcP; S2. Coat the glass surface to be etched with a film layer, and sequentially coat the peelable layer 1, the corrosion control layer 2, and the interface bonding layer 3. The peelable layer 1 is made of low polyurethane with a viscosity value of V1=0.25V. The corrosion control layer 2 is made of acrylate copolymer with a viscosity value of V2=V±3%. The interface bonding layer (3) is made of epoxy modified silicone resin with a viscosity value of V3=1.8V. S3. Laser ablation of patterns on the film surface, the patterns penetrating the film and extending to the surface of the glass to be etched; S4. The glass to be etched is placed in the etching solution for etching. The first stage of etching is low etching rate control, and the etching solution is 3%-5%HF+2%-4%H2SO4. The second stage of etching is high selective etching, and the etching solution is 2%-4%HF+6%-9%NH4HF2.

[0007] The acrylate copolymer of the corrosion inhibition control layer 2 is hydroxyl value 102 mg KOH / g + 6 wt% hydrophobic nano-SiO2.

[0008] The peelable layer 1 has a thickness of 6-8 μm, the corrosion control layer 2 has a thickness of 10-15 μm, and the interface bonding layer 3 has a thickness of 4-5 μm.

[0009] The etching temperature for the first stage is 23℃-25℃, and the etching temperature for the second stage is 30℃-32℃.

[0010] The first stage of etching is carried out in etching tank one, with an etching time of t1 = 20-24 min, reaching a target depth of 40%-45%, and forming an initial sidewall angle of 80°-82°.

[0011] The second stage of etching is carried out in tank two, with an etching time of t2 = 30 min - 36 min, and the final sidewall angle is 87° - 89°.

[0012] The amount of NH4HF2 added to the etching solution is adjusted according to the viscosity. For every 50 cP increase in viscosity, the concentration increases by 1.0 wt%-1.2 wt%.

[0013] When laser scanning is used to etch glass 4, the laser parameters are matched as follows: pulse energy: 16uJ / pulse, repetition frequency: 400kHz, and scanning strategy: spiral fill.

[0014] The first stage of etching is low-etching rate control, and the etching solution is 4.5%HF + 2%H2SO4; the second stage of etching is high-selectivity etching, and the etching solution is 3%HF + 8%NH4HF2.

[0015] When scanning the glass to be etched with a laser, ultraviolet picosecond laser is used for patterning. The laser energy satisfies E=kV+b, k=0.05-0.06, b=6-10.

[0016] This invention also relates to a special glass microstructure etching film with a simple structure that can suppress lateral penetration, eliminate film residue, stabilize etching depth, and improve product processing quality during the special glass etching process. The film includes a peelable layer 1, a corrosion control layer 2, and an interface bonding layer 3. The peelable layer 1 is made of low-polyurethane, the corrosion control layer 2 is made of acrylate copolymer, and the interface bonding layer 3 is made of epoxy-modified silicone resin.

[0017] The working principle and beneficial effects of the technical solution adopted in this invention are as follows: The special glass microstructure etching method described in this invention, Attached Figure Description

[0018] The following is a brief explanation of the contents depicted in the accompanying drawings and the markings therein: Figure 1 This is a schematic diagram of the film structure etched by the special glass microstructure described in this invention; Figure 2 Matching parameters for laser parameters.

[0019] Figure 3 Data for evaluating the effectiveness of the implementation.

[0020] Figure 4 This diagram summarizes the technical problem and technical solution of the present invention.

[0021] Figure 5 This is a performance improvement data chart for the present invention.

[0022] Figure 6 This is a performance improvement data chart for the present invention.

[0023] Figure 7This is a parameter data diagram of the membrane layer of the present invention.

[0024] The labels in the attached diagram are as follows: 1. Peelable layer; 2. Corrosion control layer; 3. Interface bonding layer; 4. Glass to be etched. Detailed Implementation

[0025] The following description, with reference to the accompanying drawings, provides a more detailed explanation of the specific embodiments of the present invention, including the shape and structure of each component, the relative positions and connections between the parts, the functions and working principles of each part: As attached Figure 1 As shown, this invention is a method for etching microstructures in special glass. S1. Set design parameters: minimum linewidth d, etching depth h, calculate target viscosity value: V=85·e (-0.12×d) +38·ln (h) =XcP;S2. Coat the film layer on the surface of the glass to be etched, and sequentially coat the peelable layer 1, the corrosion control layer 2, and the interface bonding layer 3. The peelable layer 1 is made of low polyurethane with a viscosity value of V1=0.25V. The corrosion control layer 2 is made of acrylate copolymer with a viscosity value of V2=V±3%. The interface bonding layer (3) is made of epoxy modified silicone resin with a viscosity value of V3=1.8V.S3. Laser ablate the pattern on the film layer surface. The pattern penetrates the film layer and extends to the surface of the glass to be etched.S4. Place the glass to be etched in the etching solution for etching. The first stage of etching is low etching rate control. The etching solution is 3%-5%HF+2%-4%H2SO4. The first stage of etching is high selective etching. The etching solution is 2%-4%HF+6%-9%NH4HF2.

[0026] The special glass microstructure etching method described in this invention can achieve the following beneficial effects: 1. Suppressing lateral penetration: By establishing a viscosity-linewidth exponential model, the viscosity of small-sized pattern areas is dynamically reduced, compressing the expansion rate of a 50μm linewidth to <3%; 2. Eliminating film residue: By constructing a viscosity-laser energy matching rule, the residual rate of 200-300cP film peeling is reduced to 0.5%; 3. Stabilizing etching depth: By utilizing the viscosity-depth logarithmic relationship, the depth fluctuation is controlled within ±1.8%, achieving a step height consistency of >98% for 30-100μm steps. This effectively improves processing quality.

[0027] The acrylate copolymer of the corrosion-inhibiting control layer 2 has a hydroxyl value of 102 mg KOH / g + 6 wt% hydrophobic nano-SiO2. For the above structure, viscosity control is achieved by adjusting the hydroxyl value and the solid content of the hydrophobic nano-SiO2 to make V2 = V ± 3% (V is the target calculated value). Solid content refers to the percentage by mass of the remaining non-volatile portion of the emulsion or coating after drying under specified conditions, also known as non-volatile content.

[0028] The peelable layer 1 has a thickness of 6-8 μm, the corrosion inhibition control layer 2 has a thickness of 10-15 μm, and the interface bonding layer 3 has a thickness of 4-5 μm. The above thickness control reflects the innovation: through a three-layer viscosity gradient design (V3:V2:V1=1.8:1:0.25), interface delamination is suppressed.

[0029] The etching temperature for the first stage is 23℃-25℃, and the etching temperature for the second stage is 30℃-32℃. The first stage etching is carried out in etching tank one, with an etching time t1 = 20-24 min, reaching a target depth of 40%-45% and forming an initial sidewall angle of 80°-82°. The second stage etching is carried out in tank two, with an etching time t2 = 30 min-36 min, resulting in a final sidewall angle of 87°-89°.

[0030] The amount of NH4HF2 added to the etching solution is adjusted according to the viscosity; for every 50 cP increase in viscosity, the concentration increases by 1.0 wt%-1.2 wt%. For example, 1. Microlens array (d=30μm, h=50μm) Target viscosity value calculation: V = 85·e (-0.12×30) +38·ln (50) =182cP, Then, etching adjustment: the NH4HF2 concentration is increased to 10% in the second stage.

[0031] Centipoise (cP) is the smallest unit of dynamic viscosity, used to measure the internal friction of a liquid during flow. For example, the viscosity of water at 20°C is approximately 1 cP. Viscosity is an inherent property of liquids, representing flow resistance, and cP is one of its quantification units. cP is the unit of measurement for viscosity.

[0032] When laser scanning is used to etch glass 4, the laser parameters are matched as follows: pulse energy: 16uJ / pulse, repetition frequency: 400kHz, and scanning strategy: spiral fill.

[0033] The first stage of etching is low-etching rate control, and the etching solution is 4.5%HF + 2%H2SO4; the second stage of etching is high-selectivity etching, and the etching solution is 3%HF + 8%NH4HF2.

[0034] When scanning glass to be etched using laser, ultraviolet picosecond laser patterning is employed. The laser energy satisfies E = kV + b, where k = 0.05-0.06 and b = 6-10. In the above formula, E represents electromotive force (EMF), measured in volts (V), and V represents voltage, also measured in volts (V). In the formula, it typically refers to the potential difference or input voltage in a circuit, representing the behavior under the influence of EMF. k represents the proportionality constant (constant), which has no dimension. It describes the strength of the linear relationship between EMF and voltage, depending on the characteristics of circuit components (such as resistors and inductors). b represents the intercept constant (constant), measured in volts (V). It represents the initial value of the EMF when the voltage (V = 0), corresponding to the internal voltage or offset of the power supply. This invention also relates to a special glass microstructure etching film with a simple structure that, when used in conjunction with an etching method during the etching process of special glass, can suppress lateral penetration, eliminate film residue, stabilize etching depth, and improve product processing quality. The film includes a peelable layer 1, a corrosion control layer 2, and an interface bonding layer 3. The peelable layer 1 is made of low-polymer polyurethane, the corrosion control layer 2 is made of acrylate copolymer, and the interface bonding layer 3 is made of epoxy-modified silicone resin.

[0035] In the method of this invention, regarding the setting of design parameters, an example is given as follows: Input design parameters: If the minimum linewidth d = 40 μm and the etching depth h = 60 μm, then the calculated target viscosity value is: V = 85·e (-0.12×40) +38·ln (60) =158cP. This reliably yields the specific target viscosity value.

[0036] By employing a viscosity-linewidth exponential control model, the etchant side seepage was reduced by 86%. The expansion rate of the 50μm linewidth structure was reduced from 25% in the traditional process to 1.8%. The sidewall angle increased from 70-80° to 88±0.5°, meeting the stringent requirement of >85° for micro-optical components. Viscosity-depth logarithmic control (V∝38ln(h)) eliminated nonlinear fluctuations in the etching rate: the 50μm step height deviation was ±0.9μm (compared to ±9.3μm in the original process), and the depth range of the 100×100 array was ≤1.5μm (CPK=2.1). The defect rate decreased dramatically (see...). Figure 5 The laser energy density is proportionally matched to the viscosity (E=0.05V+8 μJ), avoiding high-viscosity carbonization. The interfacial bonding layer viscosity (1.8V) provides anchoring force, and the peel strength is stable at 0.65±0.05 N / cm. The amount of acid-resistant film used is reduced by 40%: the total thickness of the three-layer structure is 25μm vs. the traditional single-layer 50μm. The scrap rate is reduced from 34.7% to 1.2%; efficiency is improved (see...). Figure 6 ).

[0037] The present invention has been described above with reference to the accompanying drawings. Obviously, the specific implementation of the present invention is not limited to the above-described manner. Any improvements made using the inventive concept and technical solution of the present invention, or the direct application of the inventive concept and technical solution to other situations without modification, are all within the protection scope of the present invention.

Claims

1. A method for etching microstructures in special glass, characterized in that: S1. Set design parameters: minimum linewidth d, etching depth h, calculate target viscosity value: V=85·e (-0.12×d) +38·ln (h) =XcP; S2. Coat the glass surface to be etched with a film layer, and sequentially coat the peelable layer (1), the corrosion control layer (2), and the interface bonding layer (3). The peelable layer (1) is made of low polyurethane with a viscosity value of V1=0.25V. The corrosion control layer (2) is made of acrylate copolymer with a viscosity value of V2=V±3%. The interface bonding layer (3) is made of epoxy modified silicone resin with a viscosity value of V3=1.8V. S3. Laser ablation of patterns on the film surface, the patterns penetrating the film and extending to the surface of the glass to be etched; S4. The glass to be etched is placed in the etching solution for etching. The first stage of etching is low etching rate control, and the etching solution is 3%-5%HF+2%-4%H2SO4. The second stage of etching is high selective etching, and the etching solution is 2%-4%HF+6%-9%NH4HF2.

2. The special glass microstructure etching method according to claim 1, characterized in that: The acrylate copolymer of the corrosion inhibition control layer (2) is hydroxyl value 102 mg KOH / g + 6 wt% hydrophobic nano SiO2.

3. The special glass microstructure etching method according to claim 1 or 2, characterized in that: The peelable layer (1) has a thickness of 6-8 μm, the corrosion control layer (2) has a thickness of 10-15 μm, and the interface bonding layer (3) has a thickness of 4-5 μm.

4. The special glass microstructure etching method according to claim 1 or 2, characterized in that: The etching temperature for the first stage is 23℃-25℃, and the etching temperature for the second stage is 30℃-32℃.

5. The special glass microstructure etching method according to claim 4, characterized in that: The first stage of etching is carried out in etching tank one, with an etching time of t1=20-24min, reaching a target depth of 40%-45%, and forming an initial sidewall angle of 80°-82°; the second stage of etching is carried out in tank two, with an etching time of t2=30min-36min, and a final sidewall angle of 87°-89°.

6. The special glass microstructure etching method according to claim 1 or 2, characterized in that: The amount of NH4HF2 added to the etching solution is adjusted according to the viscosity. For every 50 cP increase in viscosity, the concentration increases by 1.0 wt%-1.2 wt%.

7. The special glass microstructure etching method according to claim 1 or 2, characterized in that: When the laser scans the glass to be etched (4), the laser parameters are matched as follows: pulse energy: 16uJ / pulse, repetition frequency: 400kHz, scanning strategy: spiral fill.

8. The special glass microstructure etching method according to claim 1 or 2, characterized in that: The first stage of etching is low-etching rate control, and the etching solution is 4.5%HF + 2%H2SO4; the second stage of etching is high-selectivity etching, and the etching solution is 3%HF + 8%NH4HF2.

9. The special glass microstructure etching method according to claim 7, characterized in that: When scanning the glass to be etched with a laser, ultraviolet picosecond laser is used for patterning. The laser energy satisfies E=kV+b, k=0.05-0.06, b=6-10.

10. A special glass microstructure etched film layer, characterized in that: The film layer includes a peelable layer (1), a corrosion control layer (2), and an interface bonding layer (3). The peelable layer (1) is made of low polyurethane, the corrosion control layer (2) is made of acrylate copolymer, and the interface bonding layer (3) is made of epoxy modified silicone resin.

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