TWI900052B - Wafer identification device - Google Patents

Abstract

A wafer identification device includes a support unit and a working unit. The support unit includes a support and a carrier that can be movably arranged on the support along a longitudinal direction. The working unit includes a laser module arranged on the carrier, and a detection module arranged on the carrier spaced apart from the laser module. The laser module has a light source suitable for emitting a linear light extending along the longitudinal direction toward the wafer. The detection module has an image capturer for capturing the range of the linear light irradiating the wafer, and a processor connected to the image capturer. The processor is used to determine whether the number of the multiple light spots formed by the linear light on the wafers meets the expected number and confirm the distance between the light spots.

Description

Wafer identification device

The present invention relates to an auxiliary device for a semiconductor production line, and more particularly to a wafer identification device.

Referring to Figure 1, a wafer cassette 1 is used to hold multiple wafers W commonly used in semiconductor manufacturing. The cassette 1 defines a storage space 10 and has multiple carrier plates 11 extending from the left and right sides of the storage space 10 toward each other, each pairing together to support the wafers W (only one side is visible in Figure 1 due to the viewing angle). The carrier plates 11 divide the storage space 10 into multiple slots S, each for each wafer W. In a mature semiconductor production line, automated equipment removes the wafers W from the storage space 10 and then loads them into the production line for processing at each station.

However, whether the wafers W can be accurately introduced into the production line by the automated equipment depends in part on whether the wafers W are placed in the respective slots S as expected. Therefore, if a slot S is missing a wafer W, if multiple wafers W are placed in a slot S, or if a wafer W is tilted and not positioned flat on the aligned carrier plates 11, the automated equipment's ability to correctly introduce the wafers W may be affected. Similarly, even when returning the wafers W to the wafer cassette 1 after completing a specific process step, similar issues can occur, impacting subsequent processing and even the shipment of finished products.

Therefore, the purpose of the present invention is to provide a wafer identification device that can specifically detect the condition of wafers placed in a wafer cassette.

Therefore, the wafer identification device of the present invention is suitable for installation adjacent to a wafer cassette. The wafer cassette defines an internal space suitable for placing multiple wafers along a longitudinal direction. The wafer identification device includes a support unit and a working unit mounted on the support unit.

The support unit includes a bracket and a carrier movably mounted on the bracket along the longitudinal direction.

The working unit includes a laser module mounted on the stage and a detection module mounted on the stage spaced apart from the laser module. The laser module includes a light source adapted to emit a linear beam toward the wafers. The linear beam extends along the longitudinal direction when irradiated on the outer edges of the wafers. The detection module includes an image capturer for capturing a capture range of the linear beam irradiated on the wafers, and a processor connected to the image capturer. The processor is configured to determine, based on a plurality of light spots formed on the wafers by the linear light within the imaging range, whether a calculated number of the light spots meets an expected number corresponding to the imaging range, and to confirm whether a measured distance between adjacent light spots meets a specified distance.

The effect of the present invention is that the expected quantity can be properly set by utilizing the principle that the shooting range fixed by the image capture device of the detection module should correspond to a specific number of wafers. Subsequently, the support unit is used to move the work unit to an appropriate position relative to the wafer cassette to be verified. When the light source illuminates the wafers, forming the light spots, the image capturer is used to capture the image. The calculated number of light spots determined by the processor represents the number of wafers actually placed within the captured area. Therefore, the calculated number can be compared with the expected number, and the accuracy of the measured distance between adjacent wafers can be confirmed, thereby determining whether the wafers within the captured area are correctly placed.

2: Support unit

21: Bracket

22: Carrier

23: Deceleration mechanism

24: Servo Motor

3: Work Unit

31: Laser Module

311: Light Source

312: First Adjustment Seat

32: Detection Module

321: Image Capture

322: Second Adjustment Seat

323:Processor

4: Fixed unit

80: Wafer

9: Wafer Box

90: Inner Space

H: Vertical direction

Other features and functions of the present invention are clearly illustrated in the embodiments with reference to the accompanying drawings, including: Figure 1 is a fragmentary perspective view illustrating multiple wafers placed in a wafer cassette; Figure 2 is a perspective view illustrating an embodiment of the wafer identification device of the present invention; Figure 3 is a partially enlarged perspective view illustrating a support unit and a working unit of the embodiment; Figure 4 is a schematic diagram illustrating the operation of a laser module and a detection module of the working unit; Figure 5 is a schematic diagram illustrating a linear beam emitted by the laser module irradiating multiple wafers; and Figure 6 is a partially enlarged view, used in conjunction with Figure 5, illustrating the linear beam forming five light spots on the wafers.

Referring to Figure 2, an embodiment of the wafer identification device of the present invention is shown. This embodiment is suitable for installation adjacent to a wafer cassette 9. The wafer cassette 9 defines an interior space 90 suitable for accommodating multiple wafers 80 (see Figure 5) along a longitudinal direction H. This embodiment includes a support unit 2, a working unit 3 mounted on the support unit 2, and a fixing unit 4 spaced adjacent to the support unit 2 and suitable for fixing the wafer cassette 9. Specifically, the wafer cassette 9 used in this embodiment is a front-opening shipping box (FOSB) made of a transparent material.

Referring to Figures 2 and 3 , the support unit 2 comprises a bracket 21, a carrier 22 movably mounted on the bracket 21 along the longitudinal direction H, a deceleration mechanism 23 mounted on the bracket 21 and connected to the carrier 22, and a servo motor 24 connected to the deceleration mechanism 23. The form of the bracket 21 is not particularly limited and can be freely designed based on the production line environment or the need to secure various components, as long as it provides stable support and possesses sufficient structural strength. The carrier 22 is powered by the servo motor 24 and can be adjusted to its proper position along the longitudinal direction H on the bracket 21, while the deceleration mechanism 23 controls speed to optimize adjustment accuracy.

The working unit 3 includes a laser module 31 mounted on the carrier 22, and a detection module 32 spaced apart from the laser module 31 on the carrier 22. The laser module 31 has a light source 311 adapted to emit a linear beam toward the wafers 80, and a first adjustment base 312 mounted on the carrier 22 and capable of adjusting the direction of the linear beam. The linear beam extends along the longitudinal direction H when irradiating the outer edges of the wafers 80. The detection module 32 includes an image capturer 321 for capturing the range of the linear light irradiating the wafers 80, a second adjustment base 322 mounted on the stage 22 and capable of adjusting the capturing direction of the image capturer 321, and a processor 323 (shown in FIG. 4 ) connected to the image capturer 321. The image capturer 321 is a charge-coupled device (CCD). The linear light generated by the light source 311 preferably irradiates four to six wafers 80 in a positioned manner, in accordance with the range captured by the image capturer 321. In addition, the specific forms of the first adjustment base 312 and the second adjustment base 322 are not limited, as long as they can freely adjust the directions of the light source 311 and the image capturer 321.

Referring to Figure 4 in conjunction with Figure 2, the processor 323 is specifically a computing chip that can be pre-programmed with logic or installed with image processing software, and is capable of performing the required calculations and outputting results. The processor 323 receives information from the image captured by the image capturer 321 and, through image recognition, determines the number of light spots formed on the wafers 80 by the linear light within the captured range. It then determines the calculated number of these light spots, the measured distance between adjacent light spots, and the measured area of each light spot within the captured range.

Referring to Figures 4 to 6 in conjunction with Figures 2 and 3 , when inspecting the wafers 80 placed in the wafer cassette 9 using this embodiment, with the wafer cassette 9 securely positioned within the fixing unit 4 , the orientation of the light source 311 of the laser module 31 and the image capturer 321 of the detection module 32 can be pre-adjusted using the first adjustment base 312 and the second adjustment base 322 Because the wafer cassette 9 is made of a transparent material, the linear light emitted by the laser module 31 is able to pass through and directly illuminate the wafers 80 . It should be noted that when inspecting and confirming the completed wafers 80, since the fabricated structure surface is typically facing upward, to avoid unexpected reflections from the fabricated structure, the light source 311 is preferably directed upwards, as shown in Figure 4, toward the backside of the wafers 80.

Next, in conjunction with the image capture range of the image capturer 321, for example, if a single frame is set to capture five wafers 80, the laser module 31, which emits the linear light, and the detection module 32, which interprets the images formed by these light spots, can be fixed in relative position. By virtue of the stage 22's ability to move along the longitudinal direction H, they can gradually move and perform inspections on five wafers at a time.

For each frame containing the light spots captured by the image capturer 321 in conjunction with the illumination of the light source 311, the processor 323 can determine whether the calculated number of light spots, that is, the number of wafers 80, meets an expected number corresponding to the captured range (in this example, 5 wafers as shown in Figure 6). If the calculated number is confirmed to match the expected number, it can be generally determined that there are indeed 5 wafers 80 in the captured range. If the number does not match, it can be directly determined whether the number has increased or decreased. Furthermore, to address the possibility that the wafers 80 may overlap, and considering that the light spot formed by the combined reflection of the linear light from multiple overlapping wafers 80 should have a larger area, the processor 323 can also detect whether the measurement area of each light spot is within a preset reasonable range, thereby ensuring that the wafers 80 are not "overlapping." Furthermore, after presetting a standard spacing between two wafers 80 when properly positioned, image recognition is also used to confirm whether the measurement spacing between adjacent light spots meets the standard spacing, thereby detecting whether any wafers 80 are not properly positioned horizontally but are "tilted."

In summary, in this embodiment of the wafer identification device of the present invention, the laser module 31 and the detection module 32 of the working unit 3 cooperate with each other to utilize image recognition to determine whether the wafer 80 is correctly placed, and whether there are any abnormal placement conditions such as overlap, tilting, etc. This allows for specialized inspection of the wafer 80 within the wafer cassette 9, ensuring the normal operation of the back-end process and the stable shipment of finished products. Therefore, the purpose of this invention is effectively achieved.

However, the above descriptions are merely examples of the present invention and should not be construed to limit the scope of the present invention. Any simple equivalent variations and modifications made within the scope of the patent application and the contents of the patent specification are still covered by the present patent.

2: Support unit

21: Bracket

22: Carrier

23: Deceleration mechanism

24: Servo Motor

3: Work Unit

31: Laser Module

311: Light Source

32: Detection Module

321: Image Capture

4: Fixed unit

9: Wafer Box

90: Inner Space

H: Vertical direction

Claims (7)

A wafer identification device is suitable for being installed adjacent to a wafer cassette, wherein the wafer cassette defines an interior space suitable for accommodating multiple wafers along a longitudinal direction. The wafer identification device comprises: a support unit comprising a bracket and a carrier movably mounted on the bracket along the longitudinal direction; and a working unit mounted on the support unit and comprising a laser module mounted on the carrier and a detection module spaced apart from the laser module and mounted on the carrier. The laser module has a light source suitable for emitting a linear light toward the wafers, wherein the linear light extends along the longitudinal direction when irradiated on the outer edges of the wafers. The detection module has a lens for capturing the linear light irradiated on the wafers. An image capturer for a capture range of the wafers, and a processor connected to the image capturer. The processor is configured to determine, based on a plurality of light spots formed on the wafers by the linear light within the capture range, whether a calculated number of the light spots meets an expected number corresponding to the capture range, and to confirm whether a measured distance between adjacent light spots meets a specified distance. The wafer identification device as described in claim 1, wherein the support unit further includes a deceleration mechanism mounted on the bracket and connected to the carrier, and a servo motor connected to the deceleration mechanism. In the wafer identification device as described in claim 1, the laser module of the working unit further has a first adjustment base mounted on the carrier and capable of adjusting the irradiation direction of the linear light. The wafer identification device as described in claim 1, wherein the detection module of the working unit further has a second adjustment base mounted on the carrier and capable of adjusting the shooting direction of the image capturer. The wafer identification device as described in claim 1, wherein the image capturer of the detection module of the working unit is a charge-coupled photosensitive element. The wafer identification device as described in claim 1 further includes a fixing unit spaced adjacent to the supporting unit and suitable for fixing the wafer box. In the wafer identification device as described in claim 1, the processor of the detection module of the working unit is further used to determine whether a measurement area of each of the light spots in the shooting range is within a preset reasonable range.