CN-121763675-B - Metal grid exposure system and method for sapphire optical window

CN121763675BCN 121763675 BCN121763675 BCN 121763675BCN-121763675-B

Abstract

The invention relates to the technical field of optical windows, in particular to a metal grid exposure system and a metal grid exposure method for a sapphire optical window, wherein the method comprises the steps of obtaining substrate characteristic data, photoresist characteristic data, exposure light source characteristic data and pattern structure characteristic data of the metal grid of the sapphire optical window; the method comprises the steps of predicting a standing wave effect, determining exposure dose fluctuation characteristic parameters under the influence of the standing wave effect, analyzing the coupling degree of a metal grid pattern structure and the standing wave effect, determining the standing wave coupling characteristic parameters under the influence of the metal grid pattern structure, determining exposure dose fluctuation ranges of different areas of a sapphire optical window, and carrying out metal grid exposure quality early warning based on the matching relation between the exposure dose fluctuation ranges and a photoresist exposure dose process window. According to the invention, the standing wave amplification effect and the periodic resonance effect caused by the metal grid pattern structure are quantized, so that the process stability and the reliability of metal grid exposure are improved.

Inventors

XIAO YANQING
CAO YANG
ZHAO JUNZHU
CHENG KE
LIU DEXIN

Assignees

青岛华芯晶电科技有限公司
青岛芯微半导体科技有限公司

Dates

Publication Date: 20260505
Application Date: 20260304

Claims (10)

1. The metal grid exposure method for the sapphire optical window is characterized by comprising the following steps of: s1, acquiring substrate characteristic data, photoresist characteristic data, exposure light source characteristic data and pattern structure characteristic data of a metal grid of a sapphire optical window, wherein the photoresist characteristic data comprises a photoresist material refractive index and a photoresist exposure dose process window; S2, predicting the standing wave effect based on substrate characteristic data, photoresist characteristic data and exposure light source characteristic data, and determining exposure dose fluctuation characteristic parameters under the influence of the standing wave effect; S3, analyzing the coupling degree of the metal grid pattern structure and the standing wave effect based on pattern structure feature data, and determining standing wave coupling feature parameters under the influence of the metal grid pattern structure; s4, determining exposure dose fluctuation ranges of different areas of the sapphire optical window based on the exposure dose fluctuation characteristic parameters and the standing wave coupling characteristic parameters; s5, performing metal grid exposure quality early warning based on the matching relation between the exposure dose fluctuation range and the photoresist exposure dose process window.
2. The method according to claim 1, wherein determining exposure dose fluctuation characteristic parameters under the influence of standing wave effect in step S2 comprises: S21, constructing a layered medium optical structure model comprising an air layer, a photoresist layer and a sapphire substrate layer based on substrate characteristic data, photoresist characteristic data and exposure light source characteristic data; S22, performing light field propagation analysis on the layered medium optical structure model by a thin film optical transmission matrix method to obtain a light intensity distribution prediction result of exposure light in the photoresist layer along the thickness direction; S23, determining the space interval between adjacent light intensity peaks in the thickness direction of the photoresist based on a light intensity distribution prediction result, and taking the space interval mean value as an exposure dose fluctuation period; S24, determining a maximum light intensity value and a minimum light intensity value in the light intensity distribution based on a light intensity distribution prediction result, and taking the difference value between the maximum light intensity value and the minimum light intensity value as the fluctuation amplitude of exposure dose; S25, taking the exposure dose fluctuation period and the exposure dose fluctuation amplitude as exposure dose fluctuation characteristic parameters, and representing the standing wave effect intensity under the reflecting action of the sapphire substrate.
3. The method for exposing a metal grid for a sapphire optical window according to claim 1, wherein determining standing wave coupling characteristic parameters under the influence of the pattern structure of the metal grid in step S3 comprises: S31, dividing a graph area of the sapphire optical window into different subareas, and respectively extracting topological structure characteristic parameters of the metal grid in each subarea based on graph structure characteristic data, wherein the topological structure characteristic parameters comprise line width, period and cross point density of the metal grid; S32, constructing a coupling field model of a pattern structure and a standing wave effect based on strict coupling wave analysis and topological structure characteristic parameter combination, and analyzing the redistribution influence of the metal grid pattern structure on the light intensity inside the photoresist to obtain a light intensity redistribution prediction result; S33, determining the standing wave amplification coefficient and the periodic resonance coefficient of the metal grid pattern structure on the standing wave effect based on the light intensity redistribution prediction result, and taking the standing wave amplification coefficient and the periodic resonance coefficient as standing wave coupling characteristic parameters to represent the enhancement degree of the metal grid pattern structure on the standing wave effect.
4. The metal grid exposure method for a sapphire optical window according to claim 3, wherein determining the standing wave amplification factor in step S33 comprises: S331, extracting a light intensity average value in each subarea based on the light intensity distribution prediction result in the step S22, and taking the light intensity average value as a reference light intensity value under the influence of a non-graphic structure; s332, extracting a redistribution light intensity mean value in each subarea based on a light intensity redistribution prediction result, and taking the redistribution light intensity mean value as a coupling light intensity value under the influence of a metal grid pattern structure; S333, taking the ratio of the coupling light intensity value to the reference light intensity value as the standing wave amplification factor, and using the ratio as the local enhancement degree of the grid topological structure to the standing wave amplitude characteristic.
5. A metal grid exposure method for a sapphire optical window according to claim 3, wherein determining the periodic resonance coefficient in step S33 comprises: s334, determining horizontal spatial frequency based on the horizontal period of the metal grid, wherein the horizontal spatial frequency is the reciprocal of the period of the metal grid; S335, taking the reciprocal of the fluctuation period of the exposure dose as the vertical space frequency, and calculating the sine value of the included angle between the propagation direction of the exposure light source and the pattern direction of the metal grid as a direction matching factor; S336, taking the absolute value of the product of the ratio of the horizontal space frequency to the vertical space frequency and the direction matching factor as a periodic resonance coefficient, and representing the dose fluctuation superposition effect caused by the matching degree between the grid geometric period and the standing wave period.
6. The method according to claim 1, wherein determining exposure dose fluctuation ranges at different spatial positions of the sapphire optical window in step S4 comprises: S41, determining a reference dose fluctuation amplitude based on the exposure dose fluctuation amplitude and a preset exposure dose range; S42, extracting standing wave amplification coefficients and periodic resonance coefficients corresponding to all the subareas based on subarea division results in the step S33, and taking products of the standing wave amplification coefficients and the periodic resonance coefficients as local coupling enhancement coefficients corresponding to the subareas; s43, calculating the exposure dose fluctuation amplitude of each sub-region based on the reference dose fluctuation amplitude and the local coupling enhancement coefficient, and obtaining the exposure dose fluctuation range corresponding to each sub-region.
7. The method for exposing a metal grid for a sapphire optical window according to claim 1, wherein the step S5 of performing the pre-warning of the exposure quality of the metal grid comprises: And comparing the minimum value and the maximum value of the exposure dose of each sub-region with the lower limit value and the upper limit value of the photoresist exposure dose process window respectively, and only when the exposure dose fluctuation range falls into the photoresist exposure dose process window range, performing no metal grid exposure quality early warning, otherwise, performing metal grid exposure quality early warning.
8. A metal grid exposure system for a sapphire optical window for implementing the metal grid exposure method for a sapphire optical window according to any of claims 1-7, the system comprising: The data acquisition module is used for acquiring substrate characteristic data, photoresist characteristic data, exposure light source characteristic data and pattern structure characteristic data of the metal grid of the sapphire optical window, wherein the photoresist characteristic data comprises a photoresist material refractive index and a photoresist exposure dose process window; the standing wave effect prediction module is used for predicting the standing wave effect based on the substrate characteristic data, the photoresist characteristic data and the exposure light source characteristic data, and determining exposure dose fluctuation characteristic parameters under the influence of the standing wave effect; The standing wave coupling analysis module is used for analyzing the coupling degree of the metal grid pattern structure and the standing wave effect based on the pattern structure characteristic data and determining standing wave coupling characteristic parameters under the influence of the metal grid pattern structure; The fluctuation range determining module is used for determining the fluctuation range of the exposure dose in different areas of the sapphire optical window based on the fluctuation characteristic parameters of the exposure dose and the standing wave coupling characteristic parameters; And the exposure quality early warning module is used for carrying out metal grid exposure quality early warning based on the matching relation between the exposure dose fluctuation range and the photoresist exposure dose process window.
9. An electronic device comprising a processor and a memory, wherein the memory has stored therein a computer program that is callable by the processor, characterized in that the processor performs the metal grid exposure method for a sapphire optical window according to any of claims 1-7 by calling the computer program stored in the memory.
10. A computer readable storage medium storing instructions that when run on a computer cause the computer to perform the metal grid exposure method for a sapphire optical window of any of claims 1-7.

Description

Metal grid exposure system and method for sapphire optical window Technical Field The invention relates to the technical field of optical windows, in particular to a metal grid exposure system and method for a sapphire optical window. Background Sapphire materials are widely used in optical windows, infrared detection windows and high-power optical systems due to their excellent mechanical strength, high temperature resistance and good optical transmission characteristics. In order to realize the electromagnetic shielding function, the optical window needs to form a metal grid structure on the surface of the window through a photoetching process, and the pattern precision and the appearance quality of the metal grid directly influence the optical transmittance, the resistance uniformity and the reliability. However, when photolithography is performed on a sapphire substrate, exposure light is reflected and interfered for many times in the photoresist layer due to the high refractive index of sapphire, so that a standing wave effect distributed along the thickness direction of the photoresist is formed. The standing wave effect will cause periodic fluctuation of the exposure dose in the photoresist in the thickness direction, thereby causing problems such as line edge roughness, sidewall wobble or uneven development. Meanwhile, when the metal grid pattern has higher pattern density and a complex topological structure, the local intensity of the standing wave field can be further amplified through scattering and diffraction effects, so that the exposure dose distribution of different areas is obviously different. In the prior art, the suppression of standing wave effect is mostly dependent on empirical means such as anti-reflection layer design, photoresist thickness optimization or exposure dose adjustment, and a system method for quantitatively analyzing specific pattern structures is lacked. Especially under the condition that the metal grid has different periods, line widths and cross structure densities, the coupling enhancement degree of different areas to standing waves is inconsistent, and the traditional integral dose setting mode is difficult to accurately predict the local exposure failure risk. Therefore, a quantitative evaluation method capable of comprehensively considering the optical characteristics of the sapphire substrate, the photoresist process parameters and the structural characteristics of the metal grid pattern is needed, so that the spatial prediction of the fluctuation range of exposure dose is realized, and the exposure quality early warning is performed by combining the photoresist process window. Disclosure of Invention In order to overcome the defects and the shortcomings in the prior art, the invention provides the metal grid exposure system and the metal grid exposure method for the sapphire optical window, and the standing wave amplification effect and the periodic resonance effect caused by the metal grid pattern structure are quantized, so that the process stability and the reliability of metal grid exposure are improved. In order to achieve the above purpose, the present invention adopts the following technical scheme: The invention provides a metal grid exposure method for a sapphire optical window, which comprises the steps of S1, obtaining substrate characteristic data, photoresist characteristic data, exposure light source characteristic data and pattern structure characteristic data of the metal grid of the sapphire optical window, wherein the photoresist characteristic data comprises a photoresist material refractive index and a photoresist exposure dose process window, S2, predicting a standing wave effect based on the substrate characteristic data, the photoresist characteristic data and the exposure light source characteristic data, determining exposure dose fluctuation characteristic parameters under the influence of the standing wave effect, S3, analyzing the coupling degree of a pattern structure of the metal grid and the standing wave effect based on the pattern structure characteristic data, determining standing wave coupling characteristic parameters under the influence of the pattern structure of the metal grid, S4, determining exposure dose fluctuation ranges of different areas of the sapphire optical window based on the exposure dose fluctuation characteristic parameters and the standing wave coupling characteristic parameters, and S5, and carrying out metal grid exposure quality early warning based on the matching relation between the exposure dose fluctuation ranges and the photoresist exposure dose process window. Further, the determining the exposure dose fluctuation feature parameter under the influence of the standing wave effect in the step S2 includes: S21, constructing a layered medium optical structure model comprising an air layer, a photoresist layer and a sapphire substrate layer based on substrate characteristic data, photoresist characteris