Optical chip based on ALD coating film and preparation method thereof
Through ALD coating technology, the AR film layer with alternating layers is deposited on the groove surface of the waveguide structure, which solves the problem of uneven film layer deposition and achieves the efficient optical performance and functional stability of the optical chip.
Patent Information
- Application Number
- CN202510273613.0
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-03-10
- Publication Date
- 2025-06-20
AI Technical Summary
The prior art is difficult to ensure consistency in film thickness when depositing film layers on the groove surface of the waveguide structure, affecting optical characteristics and the function of the optical chip.
An optical film layer is deposited on the microstructure surface by atomic layer deposition (ALD) coating technology, and Al2O3 and SiO2 films with different refractive indices are alternately deposited with each other to form a low-reflection anti-reflection (AR) film layer.
Effective deposition in the microstructure area is achieved, high conformity and film formation uniformity of the film layer are ensured, and optical performance and functional stability of the optical chip are improved.
Smart Images
Figure CN120178423A_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to the field of silicon photonics integration technology, and particularly to an optical chip based on ALD coating and a preparation method thereof. Background Art
[0002] At present, with the expansion of the data application market and the substantial increase in system scale, the development of traditional electronic chips has increasingly approached the limit of Moore's Law. Optical chips use photons instead of electrons for transmission, can carry more information, transmit over longer distances, and can be used as a solution to break through the limit of traditional microelectronic computing. Therefore, in terms of trend, optical computing based on optical chips is expected to continuously replace the application of electronic chips in some computing scenarios. An optical chip generates optical signals through a light source, transmits the optical signals using a waveguide, and converts the optical signals into electrical signals through a detector, thereby realizing the transmission and processing of information. In the optical transmission stage, the optical signals are transmitted through a waveguide structure. To enhance the transmission and anti-interference capabilities of the optical signals, a functional film layer is usually coated on the surface of the waveguide structure.
[0003] However, ordinary coating methods can only deposit a film layer on the surface of the waveguide, and cannot ensure the film thickness uniformity of the film layer deposited on the surface of a groove with a certain aspect ratio, thereby affecting the optical properties of the thin film and resulting in a certain degree of functional loss of the optical chip. Summary of the Invention
[0004] The present invention overcomes the deficiencies of the prior art and provides an optical chip based on ALD coating and a preparation method thereof; by using ALD coating technology to deposit an optical film layer on the surface of the micro-structure to achieve certain optical properties, ensuring the effective deposition of the film layer in the micro-structure region, and meeting the various requirements of the optical chip for optical signals.
[0005] To achieve the above object, the technical solution adopted by the present invention is: an optical chip based on ALD coating, comprising: a substrate, a groove structure is provided on the substrate, an optical film layer is provided on the surface of the groove structure, the area on the substrate where the optical film layer is provided is the optical waveguide coating area, and the area on the substrate where no optical film layer is provided outside the groove structure is the non-coating area.
[0006] In a preferred embodiment of the present invention, the optical film layer is an AR film, and the AR film is formed by alternately depositing optical films with different refractive indices.
[0007] In a preferred embodiment of the present invention, the AR film is formed by alternately depositing an Al2O3 film and an SiO2 film, and the layer closest to the substrate is an Al2O3 film, achieving an optical effect of low reflection and high transmission.
[0008] In a preferred embodiment of the present invention, for the spectrum of the optical film layer, when the incident angle is 0°, the maximum reflectance in the wavelength range of 1270 - 1330 nm is less than 0.3%.
[0009] In a preferred embodiment of the present invention, the total number of optical film layers is 4 - 12 layers, and the total thickness of the film layers is 0.8 - 2.8 um.
[0010] In a preferred embodiment of the present invention, the groove width range of the groove structure in the waveguide coating area is 5 - 30 um.
[0011] In a preferred embodiment of the present invention, the groove depth range of the groove structure in the waveguide coating area is 1 - 100 um.
[0012] In a preferred embodiment of the present invention, the surface of the groove structure includes the bottom and side walls of the groove structure.
[0013] In a preferred embodiment of the present invention, the substrate is one of glass, JGS1, JGS2, K9, BK7, D263T, BF33; the substrate thickness is 0.2 - 1.0 mm.
[0014] In a preferred embodiment of the present invention, a method for preparing an optical chip based on ALD coating, used to prepare an optical chip based on ALD coating, includes the following steps: Step S1, a groove structure is provided on the substrate of the optical chip.
[0015] Step S2, photoresist masking is performed on the non - coating area outside the groove structure of the substrate.
[0016] Step S3, an optical film layer is provided on the substrate; Step S4, the photoresist on the substrate and the optical film layer on the photoresist are removed, and the optical film layer on the surface of the groove structure is retained to obtain an optical chip; Among them, the method of providing an optical film layer on the surface of the groove structure is one of thin - film deposition method, atomic layer deposition, vacuum evaporation method, magnetron sputtering method, sol - gel method.
[0017] Compared with the prior art, the beneficial effects achieved by the present invention are: The present invention discloses an optical chip based on ALD coating and its preparation method; through the ALD coating technology, an optical film layer is deposited on the surface of the micro - structure to achieve certain optical properties, ensuring the effective deposition of the film layer in the micro - structure area and meeting various requirements of the optical chip for optical signals.
[0018] By depositing the film layer through the atomic layer deposition process, the material precursor is deposited on the surface of the micro - structure without difference in three - dimensional space, effectively depositing the film layer in all directions in the micro - structure area, and then obtaining a coating sample with high conformality and uniform film formation, and the spectrum of the groove micro - structure is guaranteed to a certain extent. BRIEF DESCRIPTION OF THE DRAWINGS
[0019] The present invention will be further described below with reference to the drawings and embodiments.
[0020] Figure 1 Schematic cross-sectional view of the groove microstructure in the coating area in the preferred embodiment of the present invention; Figure 2 Flow chart for coating preparation of the optical chip in the preferred embodiment of the present invention; Figure 3 Schematic diagram of the coating process for the groove structure of the optical chip in the preferred embodiment of the present invention; Figure 4 Schematic diagram of the optical film layer structure in the preferred embodiment of the present invention; Figure 5 Reflection spectrum of the coated area of the optical chip prepared in the fourth preferred embodiment of the present invention within the wavelength range of 1270 - 1330 nm at an incident angle of 5°; Figure 6 Schematic diagram of the self-made sample in the fifth preferred embodiment of the present invention; Figure 7 Schematic diagram of the film thickness measurement points in the fifth preferred embodiment of the present invention; Figure 8 Reflection spectrum of the coated area of the optical chip prepared in Comparative Example 1 of the invention within the wavelength range of 1270 - 1330 nm at an incident angle of 5°; Figure 9 Table of designed film layer thickness parameters designed in the fourth embodiment of the invention; Figure 10 Optical test data table of the optical chips prepared in the fourth embodiment and Comparative Example 1 of the invention; Figure 11 Test results of the film layer thickness at different points in the fifth embodiment of the invention; Among them, 1 - substrate, 2 - groove structure, 21 - bottom, 22 - side wall, 3 - optical film layer. Detailed implementation manners
[0021] The technical solution of the present invention will be described in detail below through the accompanying drawings and specific embodiments. It should be understood that the embodiments of the present invention and the specific features in the embodiments are detailed descriptions of the technical solution of the present invention, rather than limitations on the technical solution of the present invention. Without conflict, the technical features in the embodiments of the present invention and the embodiments can be combined with each other.
[0022] The term "and / or" only describes the associated relationship of associated objects and indicates that three relationships can exist. For example, A and / or B can represent: A exists alone, A and B exist simultaneously, and B exists alone. In addition, the character " / " generally represents an "or" relationship between the associated objects before and after. Embodiment 1
[0023] Such as Figures 1-4As shown in the figure, an optical chip based on ALD coating includes: a substrate 1, where the substrate 1 is glass; the thickness of the substrate 1 is 0.2 - 1.0 mm. A groove structure 2 is provided on the substrate 1, and an optical film layer 3 is provided on the surface of the groove structure 2. The surface of the groove structure 2 includes the bottom 21 and the side wall 22 of the groove structure. The area on the substrate 1 where the optical film layer 3 is provided is the optical waveguide coating area, and the area on the substrate 1 where no optical film layer 3 is provided outside the groove structure 2 is the non - coating area.
[0024] Specifically, the optical film layer is an AR film, and the AR film is formed by alternately depositing optical films with different refractive indices. Among them, the AR film is formed by alternately depositing Al2O3 film and SiO2 film, and the layer closest to the substrate 1 is the Al2O3 film, achieving the optical effect of low reflection and high transmittance.
[0025] Specifically, for the spectrum of the optical film layer 3, when the incident angle is 0°, the maximum reflectance in the wavelength range of 1270 - 1330 nm is less than 0.3%. The total number of layers of the optical film layer is 4 - 12 layers, and the total thickness of the film layer is 0.8 - 2.8 um.
[0026] Specifically, the groove width range of the groove structure 2 in the optical waveguide coating area is 5 - 30 um. The groove depth range of the groove structure 2 in the optical waveguide coating area is 1 - 100 um. Embodiment 2
[0027] As Figures 1-4 shown in the figure, an optical chip based on ALD coating includes: a substrate 1, where the substrate 1 is glass; the thickness of the substrate 1 is 0.2 - 1.0 mm. A groove structure 2 is provided on the substrate 1, and an optical film layer 3 is provided on the surface of the groove structure 2. The surface of the groove structure 2 includes the bottom 21 and the side wall 22 of the groove structure. The area on the substrate 1 where the optical film layer 3 is provided is the optical waveguide coating area, and the area on the substrate 1 where no optical film layer 3 is provided outside the groove structure 2 is the non - coating area.
[0028] Specifically, the optical film layer is an AR film, and the AR film is formed by alternately depositing optical films with different refractive indices. Among them, the AR film is formed by alternately depositing Al2O3 film and SiO2 film, and the layer closest to the substrate 1 is the Al2O3 film, achieving the optical effect of low reflection and high transmittance.
[0029] Specifically, for the spectrum of the optical film layer 3, when the incident angle is 0°, the maximum reflectance in the wavelength range of 1270 - 1330 nm is less than 0.3%. The total number of layers of the optical film layer is 4 - 12 layers, and the total thickness of the film layer is 0.8 - 2.8 um. In this embodiment, the total number of layers of the optical film layer 3 is 4 layers, and the total thickness of the film layer is 0.803 um.
[0030] Specifically, the groove width range of the groove structure 2 in the optical waveguide coating area is 5 - 30 μm. The groove depth range of the groove structure 2 in the optical waveguide coating area is 1 - 100 μm. In this embodiment, the groove depth profile depth of the groove structure 2 is D, where D is 1 - 100 μm, and the bottom width of the groove width of the groove structure 2 is W, where W is 5 - 30 μm. Further, the optical film layer is deposited by ALD coating process. The schematic diagram of the optical film layer structure is as Figure 4 shown. Embodiment 3
[0031] Based on Embodiment 1 or Embodiment 2, as Figures 1-4 shown, for an optical chip based on ALD coating, the substrate 1 is one of JGS1 quartz glass, JGS2 quartz glass, K9 optical glass, BK7 optical glass, D263T optical glass, and BF33 optical glass. The optical film layer 3 is formed on the surface of the groove structure 2 by one of thin film deposition method, atomic layer deposition, vacuum evaporation method, magnetron sputtering method, and sol-gel method. Embodiment 4
[0032] A preparation method of an optical chip based on ALD coating, which is used to prepare the optical chip based on ALD coating in Embodiment 2; includes the following steps: Step S1, a groove structure 2 is provided on the substrate 1 of the optical chip.
[0033] Step S2, photoresist masking is performed on the non-coating area other than the groove structure 2 of the optical chip.
[0034] Step S3, an optical film layer 3 is provided on the substrate 1; Step S4, the photoresist on the substrate 1 and the optical film layer 3 on the photoresist are removed, and the optical film layer 3 on the surface of the groove structure 2 is retained to obtain the optical chip. More specifically, photolithographic masking is performed on the non-coating area of the optical chip in the optical waveguide coating area. Among them, the photoresist uses the photoresist in the prior art, and the selection of the photoresist will not be elaborated and listed one by one here; then the ALD technology is used to deposit the optical film layer in the groove microstructure space. After coating the groove area, the photoresist is removed by photolithographic development to obtain the optical chip.
[0035] The optical film layer 3 is an AR film, and the AR film uses optical films with different refractive indices deposited alternately. Among them, the AR film is formed by alternately depositing Al2O3 film and SiO2 film, and the layer closest to the substrate 1 is the Al2O3 film, achieving the optical effect of low reflection and high transmission. For the spectrum of the optical film layer 3, when the incident angle is 0°, the maximum reflectivity in the wavelength range of 1270 - 1330 nm is less than 0.3%. In this embodiment, the total number of layers of the optical film layer 3 is 4 layers, and the total film thickness is 0.803 μm. The schematic diagram of the optical film layer structure is as Figure 4as shown
[0036] Furthermore, the groove width of the groove structure 2 in the optical waveguide coating area is 10 um, that is, the bottom width of the groove of the groove structure 2 is W, and W is 10 um. The groove depth of the groove structure 2 in the optical waveguide coating area is 30 um, that is, the sectional depth of the groove of the groove structure 2 is D, and D is 30 um. The optical film layer is deposited by ALD coating process. The schematic diagram of the optical film layer structure is as Figure 4 shown
[0037] Specifically, the preparation flow chart is as Figure 2 shown, and the schematic diagram of the groove structure coating process is as Figure 3 shown
[0038] Among them, the design of the optical film layer 3 includes: Using Essential Macleod or TFCalc software for film system design. According to the required reflectivity requirements, simulate and optimize the thickness of each layer of thin film for the optical chip to design a low-reflection optical chip in the required wavelength band. The thickness of the film layer in the optical film layer 3 is designed as Figure 9 shown
[0039] Among them, the pretreatment when the substrate 1 is made of glass includes: Select a square white glass with a thickness of 0.5 mm, a length and width of 150×150 mm, and a grade of JGS2 as the base material. Use the laser etching process to make groove microstructures, and use the photolithography process to mask the non-coated area of the optical waveguide.
[0040] Among them, the steps for preparing the optical film layer 3 include: Put the processed substrate 1 with groove structure into a dust-free clean oven equipment of model SXCOL-480Q, set the temperature to 110°C and bake for one hour; Put the baked substrate 1 into the coating Rack tray and send it into a coating equipment of model ALDER-1000. Wait for the equipment to pump to the specified vacuum degree of 5 pa and the specified temperature of 100°C, and deposit the optical film layer on the surface of the substrate 1 by ALD coating. The precursors are trimethylaluminum and pure water, diethylaminosilane and Plasma O2, and the generated materials are Al2O3 and SiO2. Preferably, the optical film layer is deposited by atomic layer deposition (ALD) coating, vacuum evaporation coating or magnetron sputtering coating process. The ALD coating process has excellent three-dimensional conformal properties, large-area film formation uniformity and precise film thickness control. ALD coating can effectively improve the problem of uneven coating in the microstructure area.
[0041] Test the prepared optical film layer 3: Take out the sample after coating, and use the Lambda1050 instrument to perform spectral measurement on the plane of the finished product at an incident angle of 0° for the optical properties in the wavelength range of 1200 - 1400 nm. The spectral measurement results are as Figure 5 the measurement results shown. Example Five
[0042] The steps of this Example Five are basically the same as those of Example Four. The difference is that the substrate used is a self-made sample, and glass strips are manually mounted with a height of 5 mm and a spacing of 10 μm; the self-made sample is as Figure 6 shown. In this example, a single-layer Al2O3 film is deposited. This example is mainly used to verify the film thickness uniformity of the ALD groove structure coating. Therefore, the dimensions of the prefabricated groove structure 2 in this example do not need to be the same as those in Example 4, and only the optical film layer 3 needs to be deposited on the plane and the vertical surface for testing the film thickness uniformity.
[0043] Use a ME-Mapping-L type spectroscopic ellipsometer to measure and analyze the film thickness of 9 different regions of the sample. The measurement positions on the side surface are as Figure 7 shown (i.e., the schematic diagram of the ellipsometer measurement points). Measure the film thickness of the plane film layer in 3 different regions; the film thickness is as Figure 11 the test results of the Al2O3 film thickness at different positions shown. Example Six
[0044] The steps of this Example Six are basically the same as those of Example Four. The difference is that in this example, the total number of layers of the optical film layer 3 is 12 layers, and the total film thickness is 2.77 μm.
[0045] Specifically, the groove width of the groove structure 2 in the optical waveguide coating area is 30 μm; that is, the bottom width of the groove structure 2 is W, and W is 30 μm. The groove depth of the groove structure 2 in the optical waveguide coating area is 100 μm; that is, the cross-sectional depth of the groove structure 2 is D, and D is 100 μm. The optical film layer is deposited by the ALD coating process. Example Seven
[0046] The steps of this Example Seven are basically the same as those of Example Four. The difference is that the groove width of the groove structure 2 in the optical waveguide coating area is 5 μm; that is, the bottom width of the groove structure 2 is W, and W is 5 μm. The groove depth of the groove structure 2 in the optical waveguide coating area is 1 μm; that is, the cross-sectional depth of the groove structure 2 is D, and D is 1 μm. The optical film layer is deposited by the ALD coating process.
[0047] Comparative Example One The steps and parameters of this embodiment are basically the same as those of Embodiment 4, except that in this comparative example, the substrate is changed from the original JGS2 to D263T. After taking out the sample after film coating, use the Lambda1050 instrument to perform spectral measurement on the plane of the finished product at an incident angle of 0° in the wavelength range of 1200 - 1400 nm. The spectral measurement results are as Figure 8 the measurement results shown.
[0048] The tests and results are summarized as follows: First, use the 1050 instrument to perform optical tests on the optical chips prepared in Embodiment 4 and Comparative Example 1. The test method refers to the test method in the prior art. Figure 10 For the optical test results, Figure 10 the data of Embodiment 4 and Comparative Example 1 in
[0049] show that different substrates can meet the requirements of low reflection in the near-infrared wavelength range of 1270 - 1330 nm. Figure 11 The test results of the Al2O3 film thickness. From Figure 11 the results shown, the film thickness consistency of different points on the side surface of the self-made sample at a 10-um pitch is relatively high, the film thickness difference < 2 nm, and the film thickness difference between the plane and the side surface < 4 nm, thus proving that the ALD film coating method has excellent film formation uniformity in three-dimensional space coating. According to the film system design simulation, a small film thickness difference will not cause a large change in the AR reflection spectrum. Therefore, sufficient margin is reserved during design. Considering the difficulty of spectral measurement on the side surface, so on the premise of good film formation uniformity, the spectral data of the plane is used as the basis for measurement when coating the film on the micro-structured surface. The spectral data of both Embodiment 4 and Comparative Example 1 are plane spectra, and the measurement results are as Figure 10 shown.
[0050] Working principle: An optical chip based on ALD film coating and its preparation method according to the present invention; by depositing an optical film layer on the micro-structured surface through the ALD film coating technology to achieve certain optical properties, ensuring the effective deposition of the film layer in the micro-structured area and meeting various requirements of the optical chip for optical signals. The film layer is deposited by the atomic layer deposition process, and the material precursor is deposited on the micro-structured surface without difference in three-dimensional space, effectively depositing the film layer in all directions in the micro-structured area, and then obtaining a coating sample with high conformal property and uniform film formation, and the spectrum of the groove micro-structure is ensured to a certain extent. The optical chip of the present invention includes a pad non-coated area and a waveguide coated area, and an infrared low-reflection optical film layer is coated on the waveguide coated area. By using the ALD film coating technology to prepare an optical film layer in the micro-structured waveguide area with different depth-to-width ratios, it has the effect of infrared low reflection.
[0051] Based on the inspiration of the ideal embodiments of the present invention, through the above description, relevant personnel can completely make various changes and modifications without departing from the technical idea of this invention. The technical scope of this invention is not limited to the content in the specification, and the technical scope must be determined according to the scope of the claims.
Claims
1. An optical chip based on ALD coating, characterized in that: include: A substrate (1), wherein a groove structure (2) is provided on the substrate (1), an optical film layer (3) is provided on the surface of the groove structure (2), the area on the substrate (1) where the optical film layer (3) is provided is an optical waveguide coating area, and the area on the substrate (1) where the optical film layer (3) is not provided outside the groove structure (2) is a non-coating area.
2. The optical chip based on ALD coating according to claim 1, characterized in that: The optical film layer (3) is an AR film, and the AR film is an optical film with different refractive indices deposited alternately.
3. The optical chip based on ALD coating according to claim 2, characterized in that: The AR film is formed by alternately depositing an Al2O3 film and a SiO2 film, and the layer closest to the substrate (1) is an Al2O3 film, thereby achieving an optical effect of low reflection and high transmittance.
4. The optical chip based on ALD coating according to claim 3, characterized in that: The spectrum of the optical film layer (3) has a maximum reflectivity of less than 0.3% in the wavelength range of 1270-1330 nm when the incident angle is 0°.
5. The optical chip based on ALD coating according to claim 4, characterized in that: The total number of layers of the optical film layer (3) is 4-12, and the total thickness of the film layer is 0.8-2.8 um.
6. The optical chip based on ALD coating according to claim 5, characterized in that: The groove width of the groove structure (2) in the optical waveguide coating area is in the range of 5-30 um.
7. The optical chip based on ALD coating according to claim 6, characterized in that: The groove depth of the groove structure (2) in the optical waveguide coating area ranges from 1 to 100 um.
8. The optical chip based on ALD coating according to claim 7, characterized in that: The surface of the groove structure (2) comprises a bottom (21) and a side wall (22) of the groove structure.
9. The optical chip based on ALD coating according to claim 1, characterized in that: The substrate (1) is one of glass, JGS1, JGS2, K9, BK7, D263T, and BF33; the thickness of the substrate (1) is 0.2-1.0 mm.
10. A method for preparing an optical chip based on ALD coating, characterized in that: For preparing an optical chip based on ALD coating according to any one of claims 1 to 9, the preparation method comprises the following steps: Step S1, providing a groove structure (2) on a substrate (1) of an optical chip; Step S2, performing photoresist masking on the non-coated area outside the groove structure (2) of the substrate (1); Step S3, providing an optical film layer (3) on the substrate (1); Step S4, removing the photoresist on the substrate (1) and the optical film layer (3) on the photoresist, retaining the optical film layer (3) on the surface of the groove structure (2), and obtaining an optical chip; The optical film layer (3) is arranged on the surface of the groove structure (2) by using one of the following methods: thin film deposition, atomic layer deposition, vacuum evaporation, magnetron sputtering, and sol-gel method.