Quartz substrate defect detection device and method based on moire fringes

Abstract

The invention provides a quartz substrate defect detection device and method based on moire fringes, and the device comprises a laser light source, a first grating, a second grating, an image collection module, and a processing module. A to-be-measured quartz substrate is placed between the first grating and the second grating, laser beams emitted by the laser light source penetrate through the first grating to form stripe light rays, the stripe light rays deform when penetrating through the to-be-measured quartz substrate or due to defects existing in the quartz substrate, and then the stripe light rays generate Moire interference when penetrating through the second grating to form Moire fringes. The image acquisition module acquires moire fringes and converts the moire fringes into electric signals, and the processing module analyzes and judges whether the quartz substrate has defects according to the received electric signals. According to the invention, high-efficiency and non-destructive detection of defects of the quartz substrate is realized.

Description

Technical Field

[0001] The present invention relates to the technical field of substrate defect detection, and particularly relates to a quartz substrate defect detection device and method based on Moiré fringes. Background Art

[0002] During the processing of quartz substrates, from grinding and cutting, precision carving to polishing, rough polishing and fine polishing, and finally defect detection of the substrates after cleaning to determine whether they meet the quality requirements, otherwise rework is required. Therefore, detection is also very important for the entire process and quality control. Currently, the most common detection method in most factories is to use a strong light source to irradiate the surface of the substrate for manual visual inspection. However, this method is labor-consuming, and long-term eye observation will cause eye fatigue, and the strong light may cause injuries such as burns to the eyes of the inspectors; in addition, some use AOI defect detectors to directly capture the sample images by CCD and confirm the defects after comparison. However, due to the high transparency of quartz, it is not easy to focus on the sample during the detection process, which is likely to cause omissions. Moreover, the quartz substrate is a double-sided polished sample, and both sides need to be defect-detected. If one side is detected and then the other side is flipped for detection, it will increase the detection time cost. Therefore, there is an urgent need for an efficient and accurate quartz substrate defect detection method. Summary of the Invention

[0003] The purpose of the present invention is to provide a quartz substrate defect detection device and method based on Moiré fringes to improve the efficiency and accuracy of quartz substrate defect detection. To solve the above technical problems, the present invention provides a quartz substrate defect detection device based on Moiré fringes, including a laser light source, a first grating, a second grating, an image acquisition module, and a processing module; the quartz substrate to be measured is placed between the first grating and the second grating. The laser beam emitted by the laser light source passes through the first grating to form a striped light beam. When the striped light beam passes through the quartz substrate to be measured, it may deform due to the defects existing in the quartz substrate, and then Moiré interference occurs when passing through the second grating to form Moiré fringes. The image acquisition module acquires the Moiré fringes and converts them into electrical signals, and the processing module analyzes the received electrical signals to determine whether there are defects in the quartz substrate.

[0004] According to the above solution, the laser light source includes a visible light band laser and a collimating and beam expanding module; the collimating and beam expanding module collimates and expands the emitted light of the visible light band laser to form a laser beam.

[0005] According to the above solution, the visible light band laser is a helium-neon laser of 632.8 nm.

[0006] According to the above solution, the first grating and the second grating are transmissive gratings, and the relative positions of the vertical projections of the first grating and the second grating are completely coincident.

[0007] According to the above solution, the image acquisition module is a CCD camera.

[0008] According to the above solution, the processing module is set on the PC side.

[0009] According to the above solution, the quartz substrate to be measured is clamped by a fixture, and the outer shape of the fixture matches that of the quartz substrate to be measured, and the clamping surface is perpendicular to the light-transmitting surface of the quartz substrate to be measured.

[0010] According to the above solution, it is characterized in that the device is arranged in an openable enclosed space.

[0011] The present invention also discloses a method for detecting defects of a quartz substrate based on Moiré fringes, including: S1. Turn on the laser light source to generate a laser beam; S2. Collect Moiré fringes through the image acquisition module and convert them into electrical signals; the laser beam forms Moiré fringes after passing through the first grating, the quartz substrate to be measured, and the second grating in sequence, and the Moiré fringes carry the defect information of the quartz substrate to be measured; S3. Analyze the electrical signals through the processing module to judge whether the quartz substrate to be measured has defects.

[0012] According to the above solution, step S2 includes: after collecting Moiré fringes once, move the quartz substrate to be measured a distance of one grating pitch in the arrangement direction of the first grating or the second grating, and then collect Moiré fringes again.

[0013] Beneficial effects The present invention realizes the monitoring of defects on both the front and back sides of the quartz substrate to be measured at one time, without flipping the sample for repeated scanning, improving the detection efficiency; using Moiré fringes to carry the defect information of the quartz substrate, it is easy to collect and analyze the defect information, improving the analyzability of the detection results; when collecting defect information, the light-transmitting surface of the quartz substrate to be measured does not contact other substances, avoiding the introduction of new defects and realizing non-destructive detection. Description of the drawings

[0014] Figure 1 is a schematic structural diagram of a device for detecting defects of a quartz substrate based on Moiré fringes according to Embodiment 1 of the present invention; Figure 2 is a flowchart of a method for detecting defects of a quartz substrate based on Moiré fringes according to Embodiment 2 of the present invention.

[0015] In the figure: 1 - laser light source, 2 - first grating, 3 - quartz substrate to be measured, 4 - second grating, 5 - image acquisition module, 6 - processing module. Detailed implementation manners

[0016] To make the objectives, technical solutions, and advantages of the embodiments of the present disclosure clearer, the technical solutions of the embodiments of the present disclosure will be clearly and completely described below in conjunction with the accompanying drawings of the embodiments of the present disclosure. Obviously, the described embodiments are part of the embodiments of the present disclosure, rather than all of the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the described embodiments of the present disclosure without creative efforts fall within the scope of protection of the present disclosure.

[0017] Embodiment 1: Referring to Figure 1 , this embodiment discloses a quartz substrate defect detection device based on Moiré fringes, including a laser light source 1, a first grating 2, a second grating 4, an image acquisition module 5, and a processing module 6; the quartz substrate 3 to be measured is placed between the first grating 2 and the second grating 4, and the laser beam emitted by the laser light source 1 passes through the first grating 2 to form fringe light (the fringe light carries the information of the first grating 2). When the fringe light passes through the quartz substrate 3 to be measured, it may deform due to the defects existing in the quartz substrate (at this time, the fringe light also carries the defect information of the upper and lower light-transmitting surfaces of the quartz substrate), and then Moiré interference occurs when passing through the second grating 4 to form Moiré fringes (the Moiré fringes carry the defect information of the upper and lower light-transmitting surfaces of the quartz substrate). The image acquisition module 5 acquires the Moiré fringes and converts them into electrical signals, and the processing module 6 analyzes according to the received electrical signals (i.e., performs reduction analysis on the Moiré fringes) and determines whether there are defects in the quartz substrate.

[0018] Furthermore, the laser light source 1 includes a visible light band laser and a collimating and beam expanding module; the collimating and beam expanding module collimates and expands the emitted light of the visible light band laser to form a laser beam (parallel light); in this embodiment, considering that the transmittance of the quartz substrate in the ultraviolet band is greatly affected by the surface quality, and when approaching the infrared band, especially in the 2000 - 3000 nm band, the transmittance is greatly affected by the hydroxyl content of the substrate material. Considering comprehensively, a visible light band laser can be selected.

[0019] Furthermore, the visible light band laser is a helium-neon laser of 632.8 nm.

[0020] Furthermore, the first grating 2 and the second grating 4 are transmissive gratings, and the relative positions of the perpendicular projections of the first grating 2 and the second grating 4 are completely coincident; in this embodiment, the grating pitches of the first grating 2 and the second grating 4 are determined according to the defect sizes to be controlled.

[0021] Furthermore, the image acquisition module 5 is a CCD camera.

[0022] Furthermore, the processing module 6 is set on the PC side.

[0023] Further, the quartz substrate 3 to be measured is clamped by a jig, and the outer shape of the jig matches that of the quartz substrate 3 to be measured, and the clamping surface is perpendicular to the light-transmitting surface of the quartz substrate 3 to be measured; the clamping surface is located on the side, which does not affect the passage of light and does not contact the light-transmitting surface to generate new defects.

[0024] Further, it is characterized in that the device is arranged in an openable enclosed space; for example, the device is arranged in a space with an openable and closable window. After placing the quartz substrate 3 to be measured, the window is closed to form an enclosed space to avoid the influence of air disturbance on the test result.

[0025] Embodiment 2: The principle of this embodiment is basically the same as that of Embodiment 1. On the basis of Embodiment 1, this embodiment discloses a method for detecting defects of a quartz substrate based on Moiré fringes, including: S1. Turn on the laser light source 1 to generate a laser beam; in this embodiment, after turning on the laser light source 1, it needs to be preheated for a certain time before subsequent detection steps to ensure the stability of the laser beam; S2. Collect the Moiré fringes through the image acquisition module 5 and convert them into electrical signals; the laser beam passes through the first grating 2, the quartz substrate 3 to be measured, and the second grating 4 in sequence to form Moiré fringes, and the Moiré fringes carry the defect information of the quartz substrate 3 to be measured; S3. Analyze the electrical signals through the processing module 6 to judge whether the quartz substrate 3 to be measured has defects.

[0026] Further, step S2 includes: after collecting the Moiré fringes once, move the quartz substrate 3 to be measured by a grating pitch distance in the arrangement direction of the first grating 2 or the second grating 4, and then collect the Moiré fringes again; by moving the sample to be measured, the missed detection caused by the defect being located at the dark fringe is avoided.

[0027] In this embodiment, the defect situation of the quartz substrate 3 to be measured can be judged by comparing the obtained Moiré fringes with a standard image; the method for obtaining the standard image includes: after the laser is preheated and turned on, the laser beam is collimated and expanded, and then the laser beam is vertically irradiated onto the first grating 2 to obtain the fringe light controlled by the first grating 2, and the fringe light is directly irradiated onto the second grating 4 (without placing the quartz substrate 3 to be measured at this time) to obtain a complete and normal Moiré fringe image, which is used as the standard image. It should be noted that according to the needs of implementation, each step / component described in this application can be split into more steps / components, or two or more steps / components or partial operations of steps / components can be combined into new steps / components to achieve the purpose of the present invention.

[0028] Those skilled in the art can easily understand that the above are only the preferred embodiments of the present invention, and are not intended to limit the present invention. Any modifications, equivalent replacements, and improvements made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A quartz substrate defect detection device based on Moiré fringes, characterized in that, It includes a laser light source, a first grating, a second grating, an image acquisition module, and a processing module; the quartz substrate to be measured is placed between the first grating and the second grating. The laser beam emitted by the laser light source passes through the first grating to form fringe light. When the fringe light passes through the quartz substrate to be measured, it deforms due to the defects existing in the quartz substrate, and then Moiré interference occurs when passing through the second grating to form Moiré fringes. The image acquisition module acquires the Moiré fringes and converts them into electrical signals. The processing module analyzes the received electrical signals to determine whether there are defects in the quartz substrate.

2. The quartz substrate defect detection device based on Moiré fringes according to claim 1, characterized in that, The laser light source includes a visible light band laser and a collimating and beam expanding module; the collimating and beam expanding module collimates and expands the emitted light of the visible light band laser to form a laser beam.

3. The quartz substrate defect detection device based on Moiré fringes according to claim 2, wherein The visible light band laser is a helium-neon laser with a wavelength of 632.8 nm.

4. The quartz substrate defect detection device based on Moiré fringes according to claim 1, wherein The first grating and the second grating are transmissive gratings, and the relative positions of their vertical projections are completely coincident.

5. The quartz substrate defect detection device based on Moiré fringes according to claim 1, wherein, The image acquisition module is a CCD camera.

6. The quartz substrate defect detection device based on Moiré fringes according to claim 1, characterized in that, The processing module is set on the PC side.

7. The quartz substrate defect detection device based on Moiré fringes according to claim 1, characterized in that, The quartz substrate to be measured is clamped by a fixture, and the shape of the fixture matches that of the quartz substrate to be measured, and the clamping surface is perpendicular to the light passing surface of the quartz substrate to be measured.

8. The quartz substrate defect detection device based on Moiré fringes according to claim 1, characterized in that This device is set in an openable enclosed space.

9. A method for detecting defects in a quartz substrate based on Moiré fringes, characterized in that, It includes: S1. Turn on the laser light source to generate a laser beam; S2. Acquire the Moiré fringes through the image acquisition module and convert them into electrical signals; the laser beam passes through the first grating, the quartz substrate to be measured, and the second grating in sequence to form Moiré fringes, and the Moiré fringes carry the defect information of the quartz substrate to be measured; S3. Analyze the electrical signals through the processing module to determine whether there are defects in the quartz substrate to be measured.

10. The method for detecting defects of a quartz substrate based on Moiré fringes according to claim 9, wherein, Step S2 includes: after acquiring the Moiré fringes once, move the quartz substrate to be measured a distance of one grating pitch in the arrangement direction of the first grating or the second grating, and then acquire the Moiré fringes again.

Images