A method for laser-induced etching of a quartz wafer and a quartz device

Abstract

This invention relates to the field of quartz wafer manufacturing technology, and discloses a laser-induced etching process for quartz wafers and a quartz device. A hard mask is used to form a high-frequency (thin wafer), and laser-induced etching is employed to form the wafer outline. The quartz wafer processing can be completed in a single deposition and photolithography process, avoiding the multiple depositions of precious metal Au films required in photolithography, thus minimizing the amount of Au used and significantly reducing processing costs. Furthermore, quartz wafers processed using this process exhibit good side perpendicularity, high dimensional accuracy, and high quality and stability.

Description

Technical Field

[0001] This invention relates to the field of quartz wafer manufacturing technology, and in particular to a laser-induced etching process for quartz wafers and a quartz device. Background Technology

[0002] With the development of information technology, the demand for miniaturization of quartz crystal devices used for frequency generation and control in the communications field is increasing. As the core component of quartz crystal resonators, quartz wafers are developing towards miniaturization and higher frequencies. The original cutting, grinding, and polishing machining processes can no longer meet the requirements for miniaturization and higher frequencies of quartz wafers. Photolithography, similar to semiconductor processes, has emerged as a solution. The processed quartz wafers have good size and frequency consistency and high stability.

[0003] While photolithography can achieve high-quality processing of quartz wafers, the main components of the hard mask used in its fabrication are chromium (Cr) and aluminum (Au). In actual processing, the barrier layer in photolithography requires two or more Au films, and multiple rounds of photolithography, metal etching, and wafer etching processes are needed. Although aluminum can be recycled to some extent, the high production cost of photolithography for quartz substrates remains a significant factor limiting the mass production of photolithography. Summary of the Invention

[0004] The present invention provides a laser-induced etching process for quartz wafers and a quartz device, so as to solve at least one of the above-mentioned technical problems.

[0005] To achieve the above objectives, the present invention provides a laser-induced etching process for quartz wafers, comprising the following steps: S1: Clean the quartz substrate; S2: Coat the two opposite sides of the cleaned quartz substrate with a metal film; S3: Use double-sided photolithography and double-sided metal etching processes to process the metal film at two target locations on each side of the quartz substrate to create a hard mask and perform a double-sided resist removal process. S4: The quartz substrate is subjected to a first double-sided etching in a quartz etching solution to achieve a first preset thickness; wherein, the value of the first preset thickness is configured to be between the original thickness value of the wafer and the target thickness value of the wafer. S5: Laser-induced processing is performed on the frame area or patterned area in the quartz substrate that is not protected by a metal film layer to form a modified channel at two corresponding local locations on the quartz substrate; wherein the modified channel is configured such that the quartz corrosion rate is greater than that of the unmodified area; S6: The quartz substrate is subjected to a second double-sided etching in a quartz etching solution so that when the modified channel is etched through, the thickness of the patterned area of ​​the quartz substrate is etched to the target thickness value of the wafer, forming a quartz wafer with the target configuration structure. S7: Fine-tune the frequency of the quartz crystal; S8: Remove the hard mask from the surface of the quartz wafer to form a quartz wafer product.

[0006] Optionally, step S1: Cleaning the quartz substrate, specifically including: placing the quartz wafer into a cleaning machine, passing it sequentially through a chemical solution and a pure water tank, and using ultrasonic and megaphonic methods to remove organic matter and impurities adhering to the surface of the quartz substrate, and then drying the substrate for later use.

[0007] Optionally, step S2: depositing metal films on the two opposite sides of the cleaned quartz substrate, specifically including: depositing Cr film and Au film of preset thickness on the two sides of the quartz substrate by magnetron sputtering.

[0008] Optionally, step S3: using double-sided photolithography and double-sided metal etching processes to process the metal film at two target locations on each side of the quartz substrate to create a hard mask and perform a double-sided resist removal process. Specifically, this includes: using double-sided photolithography and double-sided metal etching processes to create the hard mask required for wet etching at two target locations on each side of the quartz substrate after double-sided metal film deposition, and performing a double-sided resist removal process after visually inspecting the pattern for any abnormalities.

[0009] Optionally, the two target locations are configured as two first region locations near the two ends of the two sides of the quartz substrate, and the frame region in the quartz substrate without metal film protection is configured as a first quartz substrate region between the two first region locations and the nearest end of the quartz substrate.

[0010] Optionally, the two local locations corresponding to the formation of the modification channel on the quartz substrate are configured as the two boundary locations between the first region location and the first quartz substrate region; the target configuration structure of the quartz wafer formed after the second double-sided etching is configured as an INV-MESA structure quartz wafer.

[0011] Optionally, the two target locations are configured as two second region locations at the two side ends of the quartz substrate, and the patterned area in the quartz substrate without metal film protection is configured as a second quartz substrate region between the two second region locations.

[0012] Optionally, the two local positions corresponding to the formation of the modification channel on the quartz substrate are configured such that the second quartz substrate region is close to the modification positions that are respectively close to the two first regions; the target configuration structure of the quartz wafer formed after the second double-sided etching is configured as a high-frequency flat-plate quartz wafer.

[0013] Optionally, step S7: fine-tuning the frequency of the quartz wafers, specifically including: testing the frequency of all quartz wafers on the quartz substrate to form a frequency distribution map, and fine-tuning the etching of quartz wafers of different frequencies on the substrate so that the frequency dispersion of the quartz wafers on the quartz substrate after etching is narrowed to the product requirement range.

[0014] In addition, to achieve the above objectives, the present invention also provides a quartz device configured to be prepared by the quartz wafer laser-induced etching process described in any one of the above methods.

[0015] The beneficial effects of this invention are as follows: It proposes a laser-induced etching process for quartz wafers and a quartz device. A hard mask is used to form a high-frequency (thin wafer), and laser-induced etching is employed to form the wafer outline. The quartz wafer processing can be completed in a single deposition and photolithography process, avoiding the multiple deposition of precious metal Au films required in photolithography, thus minimizing the amount of precious metal Au used and significantly reducing processing costs. Furthermore, quartz wafers processed using this process exhibit good side perpendicularity, high dimensional accuracy, and high quality and stability. Attached Figure Description

[0016] Figure 1 This is a schematic flowchart of the laser-induced etching process for quartz wafers proposed in this invention.

[0017] Figure 2 This is a schematic diagram illustrating the preparation process of the laser-induced etching process for quartz wafers with an INV-MESA structure, as proposed in this invention.

[0018] Figure 3 This is a schematic diagram illustrating the preparation process of a flat-structure quartz wafer using the laser-induced etching method for quartz wafers proposed in this invention. Detailed Implementation

[0019] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0020] It should be noted that although photolithography can achieve high-quality processing of quartz wafers, the main components of the hard mask used in its fabrication are chromium (Cr) and aluminum (Au). In actual processing, the barrier layer in photolithography needs to be deposited with two or more Au films, and multiple rounds of photolithography, metal etching, and wafer etching processes are required. Although aluminum can be recycled to some extent, the high production cost of photolithography for quartz substrates remains a significant factor limiting the mass production of photolithography.

[0021] To address the aforementioned problems, this invention proposes a laser-induced etching method and device for quartz wafers. A hard mask is used to form a high-frequency (thin wafer), and laser-induced etching is employed to form the wafer profile. The quartz wafer can be processed in a single deposition and photolithography step, avoiding the multiple depositions of precious metal Au films required in photolithography, thus minimizing the amount of Au used and significantly reducing processing costs. Furthermore, quartz wafers processed using this method exhibit good side perpendicularity, high dimensional accuracy, and high quality and stability. Specifically: like Figure 1 As shown, this embodiment of the invention provides a laser-induced etching process for quartz wafers, comprising the following steps: S1: Clean the quartz substrate; S2: Coat the two opposite sides of the cleaned quartz substrate with a metal film; S3: Use double-sided photolithography and double-sided metal etching processes to process the metal film at two target locations on each side of the quartz substrate to create a hard mask and perform a double-sided resist removal process. S4: The quartz substrate is subjected to a first double-sided etching in a quartz etching solution to achieve a first preset thickness; wherein, the value of the first preset thickness is configured to be between the original thickness value of the wafer and the target thickness value of the wafer. S5: Laser-induced processing is performed on the frame area or patterned area in the quartz substrate that is not protected by a metal film layer to form a modified channel at two corresponding local locations on the quartz substrate; wherein the modified channel is configured such that the quartz corrosion rate is greater than that of the unmodified area; S6: The quartz substrate is subjected to a second double-sided etching in a quartz etching solution so that when the modified channel is etched through, the thickness of the patterned area of ​​the quartz substrate is etched to the target thickness value of the wafer, forming a quartz wafer with the target configuration structure. S7: Fine-tune the frequency of the quartz crystal; S8: Remove the hard mask from the surface of the quartz wafer to form a quartz wafer product.

[0022] In a preferred embodiment, step S1: cleaning the quartz substrate specifically includes: placing the quartz wafer into a cleaning machine, passing it sequentially through a chemical solution and a pure water tank, and using ultrasonic and megaphonic methods to remove organic matter and impurities adhering to the surface of the quartz substrate, and then drying the substrate for later use.

[0023] In a preferred embodiment, step S2: depositing metal films on the two opposite sides of the cleaned quartz substrate, specifically including: sequentially depositing Cr film and Au film of preset thickness on the two sides of the quartz substrate by magnetron sputtering.

[0024] In a preferred embodiment, step S3: using double-sided photolithography and double-sided metal etching processes to process the metal film at two target locations on each side of the quartz substrate to create a hard mask and perform a double-sided resist removal process. Specifically, this includes: using double-sided photolithography and double-sided metal etching processes to create the hard mask required for wet etching at two target locations on each side of the quartz substrate after double-sided metal film deposition, and performing a double-sided resist removal process after visual inspection confirms that the pattern is normal.

[0025] In a preferred embodiment, the two target locations are configured as two first region locations on two sides of the quartz substrate near both ends, and the frame region in the quartz substrate without metal film protection is configured as a first quartz substrate region between the two first region locations and the nearest end of the quartz substrate.

[0026] In a preferred embodiment, the two local locations corresponding to the formation of the modified channel on the quartz substrate are configured as the two boundary locations between the first region location and the first quartz substrate region; the target configuration structure of the quartz wafer formed after the second double-sided etching is configured as an INV-MESA structure quartz wafer.

[0027] In a preferred embodiment, the two target locations are configured as two second region locations at the two side ends of a quartz substrate, and the patterned area in the quartz substrate without metal film protection is configured as a second quartz substrate region between the two second region locations.

[0028] In a preferred embodiment, the two local positions corresponding to the formation of the modification channel on the quartz substrate are configured such that the second quartz substrate region is close to the modification positions that are respectively close to the two first regions; the target configuration structure of the quartz wafer formed after the second double-sided etching is configured as a high-frequency flat-plate quartz wafer.

[0029] In a preferred embodiment, step S7: fine-tuning the frequency of the quartz wafers specifically includes: testing the frequency of all quartz wafers on the quartz substrate to form a frequency distribution map, and fine-tuning the etching of quartz wafers of different frequencies on the substrate so that the frequency dispersion of the quartz wafers on the quartz substrate after etching is narrowed to the product requirement range.

[0030] To explain the present invention more clearly, specific examples of the laser-induced etching process for quartz wafers according to the present invention are provided below for the preparation of two quartz wafer configurations.

[0031] like Figure 2 As shown, the laser-induced etching process for quartz wafers of the present invention is for the preparation of INV-MESA structure quartz wafers, and includes the following specific execution process: Step 1: Cleaning the quartz substrate. Place the quartz wafer in a cleaning machine and pass it through tanks containing chemical solutions and pure water in sequence, aided by ultrasonic and megasonological methods, to remove organic matter and other impurities adhering to the surface of the quartz substrate. After completion, dry the substrate and set it aside for use.

[0032] Step 2: Depositing the metal film. For the cleaned quartz substrate, a Cr film and an Au film of a certain thickness are deposited sequentially using magnetron sputtering. Both sides of the quartz substrate need to be deposited with the metal film.

[0033] Step 3: Fabrication of the Hard Mask. Using double-sided photolithography and double-sided metal etching processes, a hard mask is fabricated from the double-sided metal-coated quartz substrate for wet etching. After visual inspection confirms the pattern is normal, a double-sided resist removal process is performed.

[0034] Step 4: Laser-induced pre-etching. The quartz substrate undergoes a first double-sided etching process in a quartz etching solution with a specific composition to achieve a certain thickness (generally a few micrometers to tens of micrometers, which is slightly higher than the target thickness of the wafer. It should be noted that the specific value of this thickness is determined by the amount of etching after laser-induced etching). Through this etching process, the quartz substrate obtains a higher frequency (close to the target frequency).

[0035] Step 5: Laser-induced treatment. This involves treating the unprotected frame areas of the quartz substrate (see [link to details]). Figure 2 By adjusting parameters such as the pulse width and power of the femtosecond laser, a localized modification treatment is carried out on the quartz substrate, ultimately forming a modification channel at a specific local location, so that the quartz corrosion rate in the modification channel is greater than that in the unmodified area.

[0036] Step Six: Laser-Induced Etching. The quartz substrate undergoes a second double-sided etching process in a quartz etching solution with a specific composition until the channel is etched through, forming an INV-MESA structure quartz wafer. At this point, the wafer thickness is precisely etched to the target frequency (in practical applications, those skilled in the art can calculate the etching rates at modified and unmodified locations to ensure that etching through and reaching the target thickness occur simultaneously). This etching time is short, and the etching process ends just as the wafer is etched through, preventing lateral etching of the wafer sides and maintaining good perpendicularity. Furthermore, since the wafer size is primarily controlled by the induced pattern during laser induction, product dimensional accuracy is guaranteed.

[0037] Step 7: Frequency Fine-tuning. The frequencies of all the crystals on the quartz substrate are tested to form a frequency distribution map. Then, the quartz crystals of different frequencies on the substrate are finely etched. After etching, the frequency dispersion of the quartz crystals on the substrate can be narrowed to meet the product requirements.

[0038] Step 8: Remove the Hard Mask. Remove the Hard Mask from the substrate surface to reveal the final product.

[0039] like Figure 3 As shown, the laser-induced etching process for quartz wafers of the present invention is for the preparation of flat quartz wafers, and includes the following specific execution process: Step 1: Cleaning the quartz substrate. Place the quartz wafer in a cleaning machine and pass it through tanks containing chemical solutions and pure water in sequence, aided by ultrasonic and mega-acoustic methods, to remove organic matter and other impurities adhering to the surface of the quartz substrate. After completion, dry the substrate and set it aside for use. Step 2: Depositing the metal film. For the cleaned quartz substrate, a Cr film and an Au film of a certain thickness are deposited sequentially using magnetron sputtering. Both sides of the quartz substrate need to be deposited with the metal film. Step 3: Hard Mask Fabrication. Using double-sided photolithography and double-sided metal etching processes, a hard mask is fabricated from the double-sided metal-coated quartz substrate for wet etching. After visual inspection confirms the pattern is normal, a double-sided resist removal process is performed. Step 4: Laser-induced pre-etching. The quartz substrate undergoes a first double-sided etching process in a quartz etching solution with a specific composition to achieve a certain thickness (generally a few micrometers to tens of micrometers, which is slightly higher than the target thickness of the wafer. It should be noted that the specific value of this thickness is determined by the amount of etching after laser-induced etching). Through this etching process, the quartz substrate obtains a higher frequency (close to the target frequency). Step 5: Laser-induced processing. This involves treating the patterned areas on the quartz substrate that are not protected by a metal film layer (see details below). Figure 3By adjusting parameters such as the pulse width and power of the femtosecond laser, a localized modification treatment is carried out on the quartz substrate, ultimately forming a modification channel at a specific local location, making the quartz corrosion rate in the modification channel greater than that in the unmodified area. Step Six: Laser-Induced Etching. The quartz substrate undergoes a second double-sided etching process in a quartz etching solution of a specific composition until the channel is etched through, forming a high-frequency flat-sheet quartz wafer. At this point, the wafer thickness is precisely etched to the target frequency (in practical applications, those skilled in the art can calculate the etching rates at modified and unmodified locations to ensure simultaneous etching through and reaching the target thickness). This etching process is short and ends just as the wafer is etched through, preventing lateral etching of the wafer sides and maintaining good perpendicularity. Furthermore, since the wafer dimensions are primarily controlled by the induced pattern during laser induction, product dimensional accuracy is guaranteed. Step 7: Frequency fine-tuning. The frequencies of all the crystals on the quartz substrate are tested to form a frequency distribution map. Then, the quartz crystals of different frequencies on the substrate are finely etched. After etching, the frequency dispersion of the quartz crystals on the substrate can be narrowed to meet the product requirements. Step 8: Remove the Hard Mask. Remove the Hard Mask from the substrate surface to reveal the final product.

[0040] Therefore, this invention proposes a laser-induced etching method for quartz wafers. A hard mask is used to form a high-frequency (thin wafer), and laser-induced etching is employed to form the wafer profile. The quartz wafer can be processed in a single deposition and photolithography step, avoiding the multiple depositions of precious metal Au films required in photolithography, thus minimizing the amount of Au used and significantly reducing processing costs. Furthermore, quartz wafers processed using this method exhibit good side perpendicularity, high dimensional accuracy, and high quality and stability.

[0041] In another embodiment, the present invention also provides a quartz device configured to be prepared using the quartz wafer laser-induced etching process described in any of the above embodiments.

[0042] Other embodiments or specific implementations of the quartz device of the present invention can be referred to the above embodiments of the laser-induced etching processing method for quartz wafers, which will not be repeated here.

[0043] It is understood that in the description of this specification, references to terms such as "one embodiment," "another embodiment," "other embodiments," or "first embodiment to Nth embodiment," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the present invention. In this specification, illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0044] It should be noted that, in this document, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or system that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or system. Unless otherwise specified, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or system that includes that element.

[0045] The above are merely preferred embodiments of the present invention and do not limit the scope of the patent. Any equivalent structural or procedural transformations made based on the description and drawings of the present invention, or direct or indirect applications in other related technical fields, are similarly included within the scope of patent protection of the present invention.

Claims

1. A method for laser-induced etching of a quartz wafer, characterized in that Includes the following steps: S1: Clean the quartz substrate; S2: Coat the two opposite sides of the cleaned quartz substrate with a metal film; S3: Use double-sided photolithography and double-sided metal etching processes to process the metal film at two target locations on each side of the quartz substrate to create a hard mask and perform a double-sided resist removal process. S4: The quartz substrate is subjected to a first double-sided etching in a quartz etching solution to achieve a first preset thickness; wherein, the value of the first preset thickness is configured to be between the original thickness value of the wafer and the target thickness value of the wafer. S5: Laser-induced processing is performed on the frame area or patterned area in the quartz substrate that is not protected by a metal film layer to form a modified channel at two corresponding local locations on the quartz substrate; wherein the modified channel is configured such that the quartz corrosion rate is greater than that of the unmodified area; S6: The quartz substrate is subjected to a second double-sided etching in a quartz etching solution so that when the modified channel is etched through, the thickness of the patterned area of ​​the quartz substrate is etched to the target thickness value of the wafer, forming a quartz wafer with the target configuration structure. S7: Fine-tune the frequency of the quartz crystal; S8: Remove the hard mask from the surface of the quartz wafer to form a quartz wafer product.

2. The quartz wafer laser-induced etching processing method according to claim 1, wherein Step S1: Clean the quartz substrate, specifically including: placing the quartz wafer into a cleaning machine, passing it sequentially through a chemical solution and a pure water tank, and using ultrasonic and mega-acoustic methods to remove organic matter and impurities adhering to the surface of the quartz substrate. After completion, the substrate is dried and ready for use.

3. The method of claim 1, wherein the quartz wafer is rotated during the laser-induced etching. Step S2: Deposit metal films on the two opposite sides of the cleaned quartz substrate. Specifically, deposit Cr and Au films of preset thicknesses on the two sides of the quartz substrate by magnetron sputtering.

4. The method of claim 1 wherein the quartz wafer is rotated during the laser-induced etching process. Step S3: Use double-sided photolithography and double-sided metal etching processes to process the metal film at two target locations on each side of the quartz substrate to create a hard mask and perform a double-sided resist removal process. Specifically, this includes: using double-sided photolithography and double-sided metal etching processes to create the hard mask required for wet etching at two target locations on each side of the quartz substrate after double-sided metal coating, and performing a double-sided resist removal process after visually inspecting the pattern for any abnormalities.

5. The laser-induced etching method for quartz wafers as described in claim 1, characterized in that, The two target locations are configured as two first region locations on two sides of the quartz substrate near both ends, and the frame region in the quartz substrate without metal film protection is configured as a first quartz substrate region between the two first region locations and the nearest end of the quartz substrate.

6. The laser-induced etching method for quartz wafers as described in claim 5, characterized in that, The two local locations corresponding to the formation of the modification channel on the quartz substrate are configured as the two boundary locations between the first region location and the first quartz substrate region; the target configuration structure of the quartz wafer formed after the second double-sided etching is configured as an INV-MESA structure quartz wafer.

7. The laser-induced etching method for quartz wafers as described in claim 1, characterized in that, The two target locations are configured as two second region locations at the two side ends of the quartz substrate, and the patterned area in the quartz substrate without metal film protection is configured as a second quartz substrate region between the two second region locations.

8. The laser-induced etching method for quartz wafers as described in claim 7, characterized in that, The two local positions corresponding to the formation of the modification channel on the quartz substrate are configured to be close to the modification positions of the two first regions respectively in the second quartz substrate region; the target configuration structure of the quartz wafer formed after the second double-sided etching is configured as a high-frequency flat-plate quartz wafer.

9. The laser-induced etching method for quartz wafers as described in claim 1, characterized in that, Step S7: Fine-tune the frequency of the quartz crystals, specifically including: testing the frequency of all quartz crystals on the quartz substrate to form a frequency distribution map, and fine-tuning the etching of quartz crystals of different frequencies on the substrate so that the frequency dispersion of the quartz crystals on the quartz substrate after etching is narrowed to the product requirement range.

10. A quartz device, characterized in that, It is configured to be prepared using the laser-induced etching process for quartz wafers as described in any one of claims 1-9.

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