Grinding machine that can monitor wafer status

Abstract

This invention provides a grinding machine capable of monitoring wafer condition, including a stage and a grinding head. The wafer to be ground is placed on the surface of the stage, and the grinding head rotates and slides on the wafer surface to grind the wafer surface. It also includes an imaging device facing the wafer to be ground, imaging the wafer, and judging the wafer condition based on the brightness and uniformity of the image. This invention effectively overcomes the shortcomings of existing technologies by introducing an imaging device for dynamic visual inspection of the wafer surface. The imaging monitoring technology has broad adaptability to wafer materials and process types.

Description

Technical Field

[0001] This utility model relates to the field of semiconductor manufacturing equipment technology, and in particular to a grinding machine capable of monitoring wafer condition. Background Technology

[0002] In semiconductor wafer manufacturing, polishing is a commonly used critical process. Laser reflection signals are used to detect wafer breakage. However, this detection relies on light intensity feedback from a single point or localized area. If the wafer breaks, the signal intensity will only change significantly if the area where the laser is projected is fractured. However, in actual polishing processes, wafer breakage often starts at the edge or stress concentration area and propagates towards the center as cracks. If the laser detection point does not cover the cracked area, the system will be unable to detect early breakage risk, resulting in the inability to detect wafer breakage and only being able to monitor wafer breakage.

[0003] Undetected fragments of wafers may detach during the high-speed rotation of the polishing head, impacting the stage, polishing pad, or other precision components, causing mechanical deformation or sensor damage. Fragments mixed with the polishing slurry may contaminate subsequent batches of wafers, leading to batch yield losses. Equipment malfunctions caused by fragments require professional disassembly and repair, resulting in downtime of several hours or even days, severely impacting production line efficiency.

[0004] Therefore, there is an urgent practical need to develop a grinding machine that can detect debris, in order to improve the reliability, efficiency and economy of semiconductor manufacturing. Summary of the Invention

[0005] The technical problem to be solved by this utility model is to provide a grinding machine that can monitor the state of wafers and detect debris, which is of urgent practical need to improve the reliability, efficiency and economy of semiconductor manufacturing.

[0006] To address the aforementioned issues, this invention provides a grinding machine capable of monitoring wafer condition, comprising a stage and a grinding head; the wafer to be ground is disposed on the surface of the stage, and the grinding head rotates and slides on the wafer surface to achieve grinding of the wafer surface; it also includes an imaging device, which is positioned facing the wafer to be ground, images the wafer to be ground, and determines the wafer condition based on the brightness and uniformity of the image.

[0007] Optionally, it also includes a spindle head and a main spindle. The spindle head is connected to the main spindle, supports and connects to the grinding head, and drives the grinding head to rotate together with the motor inside the spindle head to grind the wafer.

[0008] Optionally, the imaging device is fixed to the side wall of the shaft head housing.

[0009] Optionally, the surface of the shaft head housing can be matte to reduce reflection.

[0010] Optionally, the imaging device is fixed to the side wall of the housing by a detachable and angle-adjustable bracket.

[0011] Optionally, the wafer is a single-crystal silicon wafer.

[0012] This invention introduces an imaging device to perform dynamic visual inspection of the wafer surface, effectively making up for the shortcomings of the prior art. The imaging monitoring technology has wide applicability to wafer materials (such as single crystal silicon and compound semiconductors) and process types (metal polishing and dielectric layer polishing). Attached Figure Description

[0013] Appendix Figure 1 The diagram shown is a structural schematic of a grinding machine capable of monitoring wafer condition according to a specific embodiment of this utility model. Detailed Implementation

[0014] The following detailed description, in conjunction with the accompanying drawings, describes the specific implementation of the grinding machine provided by this utility model, which is capable of monitoring the state of wafers.

[0015] Appendix Figure 1 The diagram shows a schematic representation of a wafer condition monitoring grinding machine according to a specific embodiment of the present invention. The machine includes a stage 10, a grinding head 20, and an imaging device 30. The wafer 40 to be ground is disposed on the surface of the stage 10. The grinding head 20 rotates and slides along the edge of the wafer 40 to grind the edge of the wafer 40. The imaging device 30 is positioned facing the wafer 40 to image it and determines the wafer condition based on the brightness and uniformity of the image.

[0016] In this specific embodiment, the wafer 40 is a single-crystal silicon wafer. Single-crystal silicon wafers are the most commonly used substrate material in semiconductor manufacturing. In other specific embodiments, any common semiconductor substrate material such as silicon carbide, silicon nitride, gallium arsenide, gallium nitride, zinc oxide, and sapphire is suitable for the above-described machine.

[0017] In this specific embodiment, the machine tool further includes a spindle head 21 and a main spindle 22. The spindle head 21 is connected to the main spindle 22, and the spindle head 21 supports and connects to the grinding head 20, driving the grinding head 20 to rotate together with the motor inside the spindle head 21 to grind the wafer 40. The imaging device 30 is fixed to the side wall of the housing of the spindle head 21 to ensure that the imaging device 30 is in a fixed position.

[0018] The surface of the housing of the spindle head 21 can be matte to reduce reflection. The imaging device 30 is fixed to the side wall of the housing by a detachable bracket 31, the angle of which can be adjusted to meet the imaging viewing angle requirements of different wafer sizes such as 8 inches and 12 inches.

[0019] In other specific embodiments, the imaging device 30 can also be fixed separately above the machine and image onto the wafer 40. The imaging device 30 determines the wafer status based on the brightness and uniformity of the image. A decrease in brightness may indicate that the entire wafer has broken off, triggering an alarm. Conversely, if the overall brightness remains unchanged but the uniformity exceeds a set threshold, it may indicate that the wafer has fragmented, with the brightness at the cracks decreasing, leading to a decrease in overall uniformity, which also requires triggering an alarm.

[0020] The imaging device 30 can employ a high-resolution industrial camera, supporting high-speed dynamic shooting to ensure clear capture of wafer surface details during the grinding process. It can also be equipped with a ring-shaped LED light source, installed around the camera, to provide uniform diffused illumination, avoiding glare interference caused by direct strong light and ensuring uniform brightness of the wafer surface image. The imaging device 30 incorporates image processing algorithms that can analyze the brightness distribution, texture features, and edge contours of the image in real time. For example, when a crack appears at the wafer edge, the reflectivity of the cracked area changes due to surface unevenness. The algorithm identifies areas of abrupt brightness changes by comparing the global brightness average; it calculates the spatial frequency distribution of the image using algorithms such as Fourier transform to determine the wafer surface flatness; and when local texture abnormalities occur (such as the appearance of dense micro-cracks), the system automatically triggers an early warning.

[0021] When the aforementioned machine is in operation, the wafer 40 is fixed on the stage 10, and the grinding head 20 is lowered to a position away from the wafer surface to await operation. The imaging device 30 initiates a self-test, adjusts the light source intensity and camera focal length, acquires an initial image of the wafer, and establishes a reference model.

[0022] The spindle 22 drives the spindle head 21 and the grinding head 20 to rotate, thus performing grinding. The imaging device 30 continuously captures images of the wafer surface at a set frame rate per second and transmits them to the control system for analysis in real time. When the image brightness non-uniformity exceeds a threshold (e.g., ±10%) or abnormal texture is detected, the system immediately issues an audible and visual alarm, and the grinding head automatically lifts and stops the machine, while simultaneously recording the coordinates of the abnormal position.

[0023] Compared to traditional laser single-point inspection, the above-mentioned technical solution enables real-time monitoring of 100% of the wafer surface area, eliminating blind spots. It is applicable to various reflective and non-reflective wafer materials such as single-crystal silicon, silicon carbide, and gallium nitride, as well as different process scenarios such as metal interconnect layer polishing and dielectric layer planarization, possessing broad industrial application value.

[0024] The above description is only a preferred embodiment of the present utility model. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present utility model, and these improvements and modifications should also be considered within the protection scope of the present utility model.

Claims

1. A grinding machine capable of monitoring the state of a wafer, characterized in that, Includes stage and grinding head; The wafer to be ground is placed on the surface of the stage, and the grinding head rotates and slides on the wafer surface to achieve grinding of the wafer surface, characterized in that: It also includes an imaging device, which is positioned toward the wafer being ground, images the wafer being ground, and determines the wafer state based on the brightness and uniformity of the image.

2. The machine tool according to claim 1, characterized in that, It also includes a spindle head and a main spindle. The spindle head is connected to the main spindle, supports and connects to the grinding head, and drives the grinding head to rotate together with the motor inside the spindle head to grind the wafer.

3. The machine tool according to claim 1, characterized in that, The imaging device is fixed to the side wall of the shaft head housing.

4. The machine tool according to claim 1, characterized in that, The surface of the shaft head housing can be matte to reduce reflection.

5. The machine tool according to claim 1, characterized in that, The imaging device is fixed to the side wall of the housing by a detachable and angle-adjustable bracket.

6. The machine tool according to claim 1, characterized in that, The wafer is a single-crystal silicon wafer.

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