Ultrathin quartz wafer appearance processing method

Abstract

The invention discloses an ultrathin quartz wafer appearance processing method. The method comprises the following steps: pasting a protective film on the surface of a quartz wafer to be processed by using a film pasting machine; the quartz wafer with the film is placed on a machining platform, a laser cutting module is arranged above the machining platform, the laser cutting module is connected with a laser generator, laser emitted by the laser cutting module irradiates the quartz wafer, and a penetrating and regular hole array is formed according to the shape, needing to be machined, of the quartz wafer; after the punching of the whole wafer is finished, the whole quartz wafer with the laser hole is separated from the protective film; and putting the separated quartz wafer into an ultrasonic wave vibration cracking device, immersing the quartz wafer into a chemical etching solvent, and carrying out ultrasonic vibration while carrying out chemical etching, so that the quartz wafer is cracked and separated along the hole array, and finally obtaining the quartz chip meeting the requirements. The problem that an existing cutting method cannot meet the requirement for high-precision machining of the appearance of the ultra-thin quartz wafer can be solved.

Description

Technical Field

[0001] The invention relates to the technical field of quartz wafer processing, in particular to a method for processing the shape of an ultra-thin quartz wafer. Background Art

[0002] With the development of science and technology and the popularization and application of 5G & AI technology, the requirements for quartz crystal oscillator products are becoming more and more stringent in terms of miniaturization, high frequency, high drive and high stability. The thickness of the core chip of quartz crystal oscillator is getting thinner and thinner. The corresponding wafer thickness of high-frequency products is 10-100um. The chip edge crack size after processing is ≤3um, the dimensional accuracy is ≤2um, no missing corners, no twin crystals, etc.

[0003] Affected by the physical properties of quartz crystal, traditional mechanical processing methods such as grinding and cutting can no longer meet the requirements of ultra-thin chip shape processing. In addition, the requirements for miniaturization are increasingly demanding on the dimensional accuracy of products. The emergence of new lasers provides conditions for solving such problems. However, the traditional continuous laser scribing method has too much continuous cutting laser energy in the processing of ultra-thin quartz chips. When cutting the chip, edge collapse and corner chipping also occur at the same time, which does not meet the quality requirements at all. Therefore, how to perform high-precision shape processing on ultra-thin quartz wafers is an urgent problem to be solved. Summary of the invention

[0004] The invention provides an ultra-thin quartz wafer profile processing method, which can solve the problem that the existing cutting method cannot meet the requirements of high-precision processing of the ultra-thin quartz wafer profile.

[0005] To achieve the above object, the present invention provides the following technical solution: a method for processing the shape of an ultra-thin quartz wafer, comprising the following steps:

[0006] S1. Use a film laminating machine to apply a protective film on the surface of the quartz wafer to be processed;

[0007] S2, placing the quartz wafer with the film on a processing platform, the processing platform can move freely in the XY plane, a laser cutting module is arranged above the processing platform, the laser cutting module is connected to a laser generator, the laser emitted by the laser cutting module irradiates the quartz wafer, and forms a regular array of holes according to the shape of the quartz wafer to be processed;

[0008] S3. After the whole wafer is drilled, the whole quartz wafer with the laser hole is separated from the protective film;

[0009] S4. The detached quartz wafer is placed in an ultrasonic vibrator and immersed in a chemical etching solvent. Ultrasonic vibration is performed while chemical etching is performed to separate the quartz wafer along the hole array, and finally a quartz chip with no broken edges or missing corners and accurate size is obtained.

[0010] Preferably, the thickness of the quartz wafer is 10-100um.

[0011] Preferably, in step S3, the entire quartz wafer with the laser hole is placed in a hollow container, and the entire hollow container is placed in a defilming solution placed in an ultrasonic device, with the liquid level submerging the chip, and then the ultrasonic wave is turned on for defilming to separate the quartz wafer from the protective film. After defilming, the quartz wafer is washed with pure water to ensure that there is no residual glue or foreign matter.

[0012] Preferably, in step S4, a rate plate is used to measure the ultrasonic vibrator's cracking rate at this time, and then the quartz wafer after film removal is placed in a chemical etching solvent together with the hollow container, the cracking time is set and the cracking is carried out. After the cracking is completed, the hollow container is taken out, cleaned with pure water, vibrated with alcohol, and finally baked.

[0013] Preferably, in step S4, the frequency before and after the split is first tested with the rate slice, and the machine split reference rate is calculated according to the split time of the rate slice, and then the split time is calculated using the split change amount and the split rate, specifically including: assuming that the frequency of the rate slice before splitting is F1, the rate slice split time is t, and the frequency of the rate slice after splitting is F2; ​​calculating the split rate v = (F2-F1) / t, assuming the split change amount is F, then the split time T = F / v.

[0014] Preferably, the laser emitted by the laser cutting module is an ultrashort pulse laser beam, and the focused beam diameter is less than 3um.

[0015] Compared with the prior art, the present invention has the following beneficial effects:

[0016] 1. Combining the processing platform that can move freely on the XY plane with the laser cutting module, quartz wafers of different shapes and thicknesses can be processed, and the size of the processable quartz wafer can be lower than 100um*100um;

[0017] 2. The chipping method combines traditional ultrasonic vibration chipping with chemical etching process for synchronous chipping, achieving a better chipping effect without damaging other parts of the wafer. After chipping, the appearance is more stable without chipping edges or corners.

[0018] 3. The overall material utilization rate can be greatly improved compared with traditional mechanical shape processing, from the traditional 30-50% to more than 80%. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 is a schematic diagram of the overall laser cutting device of the present invention;

[0020] Figure 2 This is a diagram showing the effect of laser micro-drilling of the present invention;

[0021] Figure 3 It is a dot pattern of the laser-cut quartz chip of the present invention;

[0022] Figure 4 It is a schematic cross-sectional view of the punching position after cutting of the present invention;

[0023] Figure 5 The schematic diagram of the edge of the chip after laser cutting of the present invention.

[0024] Reference numerals:

[0025] 1. Quartz wafer, 2. Protective film, 3. Processing platform, 4. Laser generator, 5. Laser cutting module. DETAILED DESCRIPTION

[0026] The technical solutions in the embodiments of the present invention will be described clearly and completely below in conjunction with the accompanying drawings in the embodiments of the present invention.

[0027] like Figure 1-5 As shown, the present invention solves the problem that the existing cutting method cannot meet the high-precision processing of the ultra-thin quartz wafer shape, and provides the following technical solutions: A method for processing the shape of an ultra-thin quartz wafer, comprising the following steps:

[0028] S1. Use a film laminating machine to paste a protective film 2 on the surface of the quartz wafer 1 to be processed. Specifically, before laminating, first confirm whether there is any abnormality in the appearance of the quartz wafer 1, and place it face down on the tray of the film laminating machine, turn on the film laminating machine to check the air pressure, clean the film laminating workbench, place the iron ring at the specified position, place the positioning block on the chassis and align it with the positioning point, then place the quartz wafer 1 on the workbench, close to the positioning block, turn on the vacuum, so that the quartz wafer 1 is sucked and fixed to the workbench, and then after removing the positioning block, wipe the surface of the quartz wafer 1 with a dust-free cloth moistened with alcohol, click to start the automatic film laminating machine, remove the film-pasted material, cut and tear off the excess film, release the vacuum, and insert the film-pasted quartz wafer 1 and the iron ring into the loading fixture box;

[0029] S2. Place the quartz wafer with film on the processing platform 3. The processing platform 3 can move freely in the XY plane. A laser cutting module 5 is arranged above the processing platform 3. The laser cutting module 5 is connected to the laser generator 4. The laser emitted by the laser cutting module 5 irradiates the quartz wafer 1 to form a regular array of holes according to the shape of the quartz wafer 1 to be processed. In this step, it is necessary to first confirm whether the environment for laser cutting meets the requirements. In this embodiment, the preferred cutting processing environment is a temperature of 20±3°C and a humidity of 45±10%. Before cutting, place the loading jig box in the loading area of ​​the processing platform 3. After placing it, click loading, enter the production information in the automatic mode, and click matching. The control system of the processing platform 3 will automatically give a cutting recipe, and then click start automatically. The machine automatically runs to start cutting. After cutting, remove the material box. During the whole process, the operator has no contact with the quartz wafer 1. Figure 3-4 As shown, after cutting by the laser cutting device, the punching effect of the quartz wafer 1 is visible, the horizontal and vertical points are clear, and the holes after cutting are through holes at various locations with consistent spacing.

[0030] Among them, the laser emitted by the laser cutting module 5 is an ultrashort pulse laser beam, and the focused beam diameter is less than 3um. The laser generator 4 can adopt an infrared-femtosecond laser, and some of its parameters are wavelength: 1030nm, repetition frequency: 100KHZ, pulse width: 200fs, average output: 5~10W, and processing speed: 100mm / s.

[0031] S3, after the whole wafer is drilled, the whole quartz wafer 1 with the laser hole is separated from the protective film 2;

[0032] S4. The detached quartz wafer 1 is placed in an ultrasonic vibrator and immersed in a chemical etching solvent. Ultrasonic vibration is performed during chemical etching to separate the quartz wafer 1 along the hole array, and finally a quartz chip with no broken edges or missing corners and accurate size is obtained.

[0033] In this embodiment, the thickness of the quartz wafer 1 is 10-100 um.

[0034] Among them, in the above step S3, the whole quartz wafer 1 with the laser hole is placed in a hollow container, and the hollow container is placed in the film removal solution placed in the ultrasonic device, the liquid level immerses the chip, and then the ultrasonic wave is turned on for film removal, so that the quartz wafer 1 is separated from the protective film 2, and the quartz wafer 1 after film removal is washed with pure water to ensure that there is no residual glue or foreign matter. The film removal solution is preferably a D326 mixed solution, which is an alkaline cleaning agent that mainly removes some foreign matter on the quartz surface. The main components are a mixture of polyoxyethylene alkyl ether, sodium hydroxide, potassium hydroxide, water, etc., wherein the film removal temperature is 80℃±5℃, the time is 10 to 15 minutes, and the time for rinsing with pure water is also about 10 minutes. The hollow container here can be a commonly used basket, basket, etc.

[0035] As the last step, the quartz wafer 1 needs to be split. It is necessary to select a suitable ultrasonic vibration intensity. During the vibration, the quartz wafer 1 undergoes a chemical etching reaction at the same time. It can just separate the wafer from the punched part without damaging other parts of the wafer. Experiments have shown that if only ultrasonic vibration is performed, for ultra-thin quartz chips, if the intensity is too low, some chips will not be able to split and separate normally. Increasing the intensity will increase the yield of splitting, and a large number of broken edges and abnormal appearance will appear. Therefore, the present invention combines mechanical vibration and chemical etching to perform splitting, and finally obtains a quartz chip with no broken edges, missing corners, and precise size.

[0036] In this embodiment, in order to better improve the efficiency and accuracy of the splitting, it is necessary to set the vibration rate of the ultrasonic vibrator. Therefore, in step S4, a rate plate is used to measure the splitting rate of the ultrasonic vibrator at this time, and then the quartz wafer 1 after film stripping is placed in a chemical etching solvent together with the hollow container, the splitting time is set and the splitting is carried out. After the splitting is completed, the hollow container is taken out and cleaned with pure water. In step S4, the frequency before and after the splitting is first tested with a rate sheet, and the machine splitting reference rate is calculated according to the splitting time of the rate sheet, and then the splitting time is calculated by the splitting change and the splitting rate, specifically including: assuming that the frequency of the rate sheet before splitting is F1, the rate sheet splitting time is t, and the frequency of the rate sheet after splitting is F2; ​​calculating the splitting rate v = (F2-F1) / t, assuming the splitting change is F, then the splitting time T = F / v, wherein the rate sheet refers to the actual splitting etching performed on the sample sheet before the formal product operation to obtain the splitting rate of the current solution, and the splitting change F is actually different for each product, such as the product frequency before splitting is F3, the target frequency after the product splitting is F4, and the splitting change F = F4-F3, so it needs to be determined through experiments.

[0037] In this embodiment, the quartz wafer 1 after processing needs to be vibrated with alcohol and then baked, wherein the oven temperature is 140° C.±5° C. and the baking time is 25 min±5 min, so as to dry the liquid on the surface of the quartz wafer 1 .

[0038] In this embodiment, the actual experimental data of the laser drilling experiment (45um wafer thickness) is as follows:

[0039]

[0040] Based on the above experimental results, the optimal solution for the size and spacing of holes in wafers of different thicknesses is obtained through experiments. Among them, twinning defect refers to the misalignment of different lattice planes of quartz crystal, which is an undesirable phenomenon. This phenomenon is a defective product. The expected proportion of twinning is 0. From the above table, it can be seen that the edge crack size in experimental groups 4 and 5 is less than 3um, and the twinning defect ratio is 0, so the drilling diameter and hole spacing in experimental groups 4 and 5 can meet the process requirements.

[0041] It should be noted that all directional indications in the embodiments of the present invention (such as up, down, left, right, front, back, etc.) are only used to explain the relative position relationship, movement status, etc. between the components under a certain specific posture (as shown in the accompanying drawings). If the specific posture changes, the directional indication will also change accordingly.

[0042] In addition, in the present invention, descriptions such as "first", "second", etc. are only used for descriptive purposes and cannot be understood as indicating or implying their relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" or "second" may explicitly or implicitly include at least one of the features. In the description of the present invention, the meaning of "plurality" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0043] In the present invention, unless otherwise clearly specified and limited, the terms "connection", "fixation", etc. should be understood in a broad sense. For example, "fixation" can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements, unless otherwise clearly defined. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0044] In addition, the technical solutions between the various embodiments of the present invention can be combined with each other, but it must be based on the fact that ordinary technicians in the field can implement it. When the combination of technical solutions is contradictory or cannot be implemented, it should be deemed that such combination of technical solutions does not exist and is not within the scope of protection required by the present invention.

Claims

1. A method for processing the shape of an ultra-thin quartz wafer, characterized in that: The steps include: S1, using a film laminating machine to affix a protective film (2) to the surface of a quartz wafer (1) to be processed; S2. Placing the quartz wafer with the film on a processing platform (3), wherein the processing platform (3) can move freely in an XY plane, and a laser cutting module (5) is arranged above the processing platform (3). The laser cutting module (5) is connected to a laser generator (4). The laser emitted by the laser cutting module (5) irradiates the quartz wafer (1), and forms a regular array of holes according to the shape of the quartz wafer (1) to be processed; S3, when the whole wafer is drilled, the whole quartz wafer (1) with the laser hole left is stripped from the protective film (2); S4. The detached quartz wafer (1) is placed in an ultrasonic vibrator and immersed in a chemical etching solvent. Ultrasonic vibration is performed during chemical etching to separate the quartz wafer (1) along the hole array, and finally a quartz chip with no broken edges or missing corners and accurate size is obtained.

2. The method for processing the outer shape of an ultra-thin quartz wafer according to claim 1, characterized in that: The thickness of the quartz wafer (1) is 10-100 um.

3. The method for processing the outer shape of an ultra-thin quartz wafer according to claim 1, characterized in that: In step S3, the whole quartz wafer (1) with the laser hole is placed in a hollow container, and the hollow container is placed in a defilming solution placed in an ultrasonic device, the liquid level immerses the chip, and then the ultrasonic wave is turned on to defilm, so that the quartz wafer (1) is separated from the protective film (2). After the defilming, the quartz wafer (1) is washed with pure water to ensure that there is no residual glue or foreign matter.

4. The method for processing the outer shape of an ultra-thin quartz wafer according to claim 3, characterized in that: In step S4, the ultrasonic vibrator cracking rate is first measured with a rate plate, and then the quartz wafer (1) after film removal is placed in a chemical etching solvent together with the hollow container, the cracking time is set and the cracking is carried out. After the cracking is completed, the hollow container is taken out, cleaned with pure water, vibrated with alcohol, and finally baked.

5. The method for processing the outer shape of an ultra-thin quartz wafer according to claim 4, characterized in that: In step S4, the rate slice is first used to test the frequencies before and after the split, and the machine split reference rate is calculated according to the split time of the rate slice, and then the split time is calculated using the split change amount and the split rate, specifically including: assuming that the frequency of the rate slice before splitting is F1, the rate slice split time is t, and the frequency of the rate slice after splitting is F2; ​​calculating the split rate v = (F2-F1) / t, assuming the split change amount is F, then the split time T = F / v.

6. The method for processing the outer shape of an ultra-thin quartz wafer according to claim 1, characterized in that: The laser emitted by the laser cutting module (5) is an ultrashort pulse laser beam, and the focused beam diameter is less than 3 μm.

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