Search

CN-122018243-A - Optical waveguide master mask defect self-adaptive photoetching method based on Talbot self-imaging

CN122018243ACN 122018243 ACN122018243 ACN 122018243ACN-122018243-A

Abstract

The invention relates to the technical field of photoetching, in particular to a self-adaptive photoetching method for defects of an optical waveguide master mask based on Talbot self-imaging, which comprises the steps of collecting design period and exposure wavelength parameters of the optical waveguide master mask, calculating the Talbot self-imaging distance, and driving a substrate coated with photoresist to be accurately positioned at the distance; starting coherent light output after positioning is finished, controlling a substrate to perform periodic motion in a plane, and optically counteracting distortion components caused by defects in a propagation process of a diffraction light field by utilizing a Fresnel diffraction effect to generate uniform light intensity distribution; the photoresist records the distribution, forms a grating structure through development, and completes the preparation of the optical waveguide template through etching and deposition processes. The invention can realize defect inhibition on the optical level, improve the structural integrity and the preparation consistency of the template, reduce the scrapping requirement of the master plate and reduce the production cost.

Inventors

  • XIAO XIANGFENG
  • LIU HAILONG
  • Liang caihong

Assignees

  • 深圳市瀚思通汽车电子有限公司

Dates

Publication Date
20260512
Application Date
20260227

Claims (10)

  1. 1. The self-adaptive photoetching method for the defects of the optical waveguide master plate based on Talbot self-imaging is characterized by comprising the following steps of: Step 1, collecting a design period value of an optical waveguide master plate and a coherent light wavelength value for exposure to generate a parameter data packet; step 2, extracting a design period value and a wavelength value from the parameter data packet, and performing calculation on the design period value and the wavelength value to obtain a Talbot self-imaging distance value; Step 3, converting the Talbot self-imaging distance value into a displacement control signal to drive the substrate coated with the photoresist to move, and judging that the positioning is finished when the difference value between the measured value of the distance between the substrate and the master plate and the Talbot self-imaging distance value is smaller than a set threshold value; Step 4, under the positioning completion state, starting coherent light output, and simultaneously controlling the substrate to perform periodic motion in a plane according to preset frequency parameters and amplitude parameters; Step 5, coherent light passes through the optical waveguide mother plate to form a diffraction light field, and the diffraction light field counteracts distortion components caused by defects through a Fresnel diffraction effect in the process of propagating to the substrate position, wherein the distortion components are uneven parts of the diffraction light field caused by the defects; And 6, recording the light intensity distribution of the photoresist after offset treatment, forming a grating structure by treatment of a developing solution, and completing preparation of the optical waveguide template by etching and depositing the waveguide functional layer.
  2. 2. The method of adaptive photolithography for defects of an optical waveguide master based on taber self-imaging according to claim 1, wherein step 1 comprises: Reading a period label in an optical waveguide master design drawing to generate a first design period value, or scanning the surface of the master by using optical measurement equipment, collecting an original period signal, digitally filtering the original period signal, and outputting a second design period value; Collecting a wavelength nominal value of a laser source, monitoring an actual spectrum output by laser by using a spectrometer, comparing the wavelength nominal value with a central wavelength of the actual spectrum, and outputting a wavelength value; And carrying out data encapsulation on the first design period value or the second design period value and the wavelength value to generate a parameter data packet.
  3. 3. The method of adaptive photolithography for defects of optical waveguide masters based on taber self-imaging according to claim 2, wherein step 2 comprises: receiving a parameter data packet, and separating a design period value and a wavelength value from the parameter data packet; Square calculation is carried out on the separated design period value to generate a period square value, reciprocal calculation is carried out on the separated wavelength value to generate a wavelength reciprocal value; Multiplying the periodic square value by the wavelength reciprocal value to obtain a Talbot distance preliminary calculation result; And taking the initial calculation result of the Talbot distance as an initial distance parameter, executing optical diffraction simulation calculation, and iteratively adjusting the initial distance parameter if the light field uniformity value output by the simulation calculation is lower than a preset standard value until the light field uniformity value reaches the preset standard value, and outputting a final Talbot self-imaging distance value.
  4. 4. The method of adaptive photolithography for defects of an optical waveguide master based on taber self-imaging according to claim 3, wherein the step 3 comprises: Reading the Talbot self-imaging distance value, and generating a displacement control signal based on the Talbot self-imaging distance value, wherein the displacement control signal controls the substrate to move towards the optical waveguide master plate; Measuring the real-time distance between the surface of the substrate and the surface of the master plate to obtain a real-time distance measurement value; Calculating an absolute difference value between the real-time distance measurement value and the Talbot self-imaging distance value, and judging whether the absolute difference value is smaller than a set threshold value or not; if the absolute difference value is greater than or equal to the set threshold value, generating a feedback control signal according to the positive and negative of the difference value, and superposing the feedback control signal to the displacement control signal to enable the value of the displacement control signal to be adjusted according to the difference value proportion, and guiding the substrate to continuously move; If the absolute difference is smaller than the set threshold, stopping generating the feedback control signal and outputting a positioning completion state signal.
  5. 5. The method of adaptive photolithography for defects of a master optical waveguide based on taber self-imaging according to claim 4, wherein the step 4 comprises: Receiving a positioning completion status signal; responding to the positioning completion state signal, generating coherent light, and modulating the coherent light to form a uniform illumination light field; determining a substrate movement frequency parameter and an amplitude parameter according to the photosensitive characteristic of the photoresist and the period of the target grating structure; controlling the substrate to perform in-plane reciprocating motion according to the frequency parameter and the amplitude parameter; In the reciprocating motion process, monitoring actual displacement data of a substrate, comparing the actual displacement data with frequency parameters and amplitude parameters, and if the deviation exceeds a tolerance, adjusting the amplitude parameters in the motion control parameters according to the equal ratio of the deviation.
  6. 6. The adaptive photolithography method for defects of optical waveguide master based on taber self-imaging according to claim 5, wherein step 5 comprises: Receiving the uniform illumination light field formed in the step 4, wherein the uniform illumination light field irradiates the optical waveguide mother plate with the defects; the periodic structure and the defects on the optical waveguide master plate modulate an illumination light field together to generate a diffraction light field, wherein the diffraction light field comprises master plate structure information and defect information; The diffraction light field propagates from the optical waveguide master plate to the substrate position, a plurality of acquisition points are arranged on the diffraction light field propagation path, and phase data and amplitude data of the diffraction light field at the acquisition points are acquired through a photoelectric detector; Performing Fourier transform on the phase data and the amplitude data, converting the diffraction light field into a spatial frequency spectrum, and identifying a high-frequency component corresponding to the master plate periodic structure and a low-frequency component corresponding to the defect distortion from the spatial frequency spectrum; based on the Talbot self-imaging principle, the high-frequency components are coherently overlapped due to periodic matching at the Talbot self-imaging distance, the light intensity is enhanced to be more than 1.5 times of the original value, the low-frequency components are scattered due to non-periodic characteristics at the Talbot self-imaging distance, and the light intensity is attenuated to be less than 30% of the original value; and synthesizing the enhanced high-frequency component and the attenuated low-frequency component at the substrate position to obtain the uniform light intensity distribution.
  7. 7. The adaptive photolithography method for optical waveguide master defect based on taber self-imaging according to claim 6, wherein in step 6, the photoresist records the light intensity distribution after the offset processing, and the grating structure is formed by processing with a developing solution, comprising: propagating the homogenized light intensity distribution obtained in the step 5 to the surface of the substrate coated with the photoresist through an optical system; the homogenized light intensity distribution acts on the photoresist layer to enable photosensitive components in the photoresist to absorb photon energy in the light intensity distribution; The photosensitive component absorbs photon energy and then generates photochemical reaction, so that the photosensitive component in the exposure area generates crosslinking or decomposition; Forming a grating pattern potentially on the surface in the photoresist layer based on the spatial intensity variation of the light intensity distribution, wherein the region with the light intensity higher than the photoresist photosensitive threshold value generates complete photochemical reaction, and the region with the light intensity lower than the photoresist photosensitive threshold value generates incomplete photochemical reaction; Coating a developing solution on the surface of the photoresist, dissolving the photoresist area which does not have complete photochemical reaction, and reserving the photoresist area which has complete photochemical reaction; After dissolution treatment, a grating structure corresponding to the homogenized light intensity distribution is formed on the surface of the photoresist.
  8. 8. The adaptive photolithography method for defects of optical waveguide master based on taber self-imaging according to claim 7, wherein in step 6, the preparing of the optical waveguide template is completed by etching and depositing the functional layer of the waveguide, comprising: Performing surface morphology measurement on the grating structure formed after development to obtain grating groove depth data, line width data and cycle size data; according to the grating groove depth data, the line width data and the cycle size data, calculating etching time parameters, etching gas flow parameters and power parameters; etching is carried out according to the etching time parameter, the etching gas flow parameter and the power parameter, and the grating pattern on the surface of the photoresist is transferred into a substrate material; depositing waveguide functional materials on the surface of the substrate after pattern transfer according to preset thickness requirements and refractive index requirements; and (3) performing optical performance test on the template after the waveguide functional material is deposited, measuring transmission loss and diffraction efficiency, comparing the measurement result with the template performance prepared by the defect-free master plate, and outputting defect suppression effect evaluation data.
  9. 9. The taber self-imaging based optical waveguide master defect adaptive lithography method of claim 8, further comprising: Acquiring current distance data of the substrate and the master plate in real time from the step 3, and acquiring movement frequency data and amplitude data of the substrate in real time from the step 4; Establishing a corresponding relation between the distance data and the motion frequency data and between the distance data and the motion amplitude data; When the difference value between the current distance data and the Talbot self-imaging distance value is smaller than 2 times of a set threshold value, reducing the motion amplitude data to 50% of an original value; when deviation occurs in the substrate movement track, the feedback control signal in the step 3 is adjusted; the generation of the localization completion status signal satisfies both the distance threshold condition and the motion stability condition.
  10. 10. The taber self-imaging based optical waveguide master defect adaptive lithography method of claim 9, further comprising: the Talbot self-imaging distance value output in the step 2 is used as a generation basis of the displacement control signal in the step 3; The positioning completion state signal generated in the step 3 is used as a trigger condition for starting the exposure in the step 4; the substrate movement starting time and the coherent light output starting time of the step 4 are kept synchronous; Monitoring a taber self-imaging distance value, an actual distance measurement value, movement frequency data, movement amplitude data and light intensity distribution data; And when any item of data exceeds a preset normal range threshold, suspending the flow and generating a specific adjustment instruction, wherein the adjustment instruction comprises a data name, an offset and an adjustment direction, and continuing to execute after the data is restored to be within the normal range threshold.

Description

Optical waveguide master mask defect self-adaptive photoetching method based on Talbot self-imaging Technical Field The invention relates to the technical field of photoetching, in particular to an optical waveguide master plate defect self-adaptive photoetching method based on Talbot self-imaging. Background In the application scene of the optical waveguide template photoetching preparation technology, talbot self-imaging is an optical phenomenon, repeated self-imaging patterns are generated by utilizing periodic diffraction, a high-resolution exposure template is provided for a photoetching process, an optical waveguide master plate is an original template for copying an optical waveguide structure, the preparation precision of the optical waveguide master plate is related to the performance of an optical waveguide device, and defect self-adaptive photoetching is a photoetching method for compensating manufacturing defects by monitoring and adjusting exposure parameters in real time, and the periodic characteristics of Talbot self-imaging are combined, so that pattern generation can be optimized when the optical waveguide master plate is prepared, defect influence is reduced, and the preparation quality of the template is improved. The existing optical waveguide master defect self-adaptive photoetching technology has the following technical pain points, particularly in the existing near-contact or contact photoetching technology, micron or nano-scale defects such as scratches, broken lines or cycle disorders on the surface of an optical waveguide master can be directly transmitted to a photoresist template, and the defect transmission process lacks an effective inhibition mechanism, for example, the scratch defects of the master can lead to the formation of corresponding grooves on the surface of the template, the pattern defects of the master can lead to the loss of grating lines of the template, the transmission of the defects leads to the structural integrity damage of the template, and the optical waveguide device prepared based on the defect template has the performance degradation problems such as waveguide loss increase or diffraction efficiency decrease. Disclosure of Invention Aiming at the defects of the prior art, the invention provides an optical waveguide master mask defect self-adaptive photoetching method based on Talbot self-imaging, which solves the technical problem of optical waveguide performance degradation caused by the fact that the transmission of defects in a copying template cannot be effectively inhibited. In order to solve the technical problems, the invention comprises the following specific contents: The invention provides an optical waveguide master mask defect self-adaptive photoetching method based on Talbot self-imaging, which comprises the following steps: Step 1, collecting a design period value of an optical waveguide master plate and a coherent light wavelength value for exposure to generate a parameter data packet; step 2, extracting a design period value and a wavelength value from the parameter data packet, and performing calculation on the design period value and the wavelength value to obtain a Talbot self-imaging distance value; Step 3, converting the Talbot self-imaging distance value into a displacement control signal to drive the substrate coated with the photoresist to move, and judging that the positioning is finished when the difference value between the measured value of the distance between the substrate and the master plate and the Talbot self-imaging distance value is smaller than a set threshold value; Step 4, under the positioning completion state, starting coherent light output, and simultaneously controlling the substrate to perform periodic motion in a plane according to preset frequency parameters and amplitude parameters; Step 5, coherent light passes through the optical waveguide mother plate to form a diffraction light field, and the diffraction light field counteracts distortion components caused by defects through a Fresnel diffraction effect in the process of propagating to the substrate position, wherein the distortion components are uneven parts of the diffraction light field caused by the defects; And 6, recording the light intensity distribution of the photoresist after offset treatment, forming a grating structure by treatment of a developing solution, and completing preparation of the optical waveguide template by etching and depositing the waveguide functional layer. Further, in the step 1, the collecting the design period value of the optical waveguide master and the value of the wavelength of the coherent light for exposure to generate the parameter data packet includes: Reading a period label in an optical waveguide master design drawing to generate a first design period value, or scanning the surface of the master by using optical measurement equipment, collecting an original period signal, digitally filtering the original period