A micro-motion wafer center offset detection device
By installing a vertical strip photoelectric sensor on a wafer handling robot to obtain the wafer center coordinates, the problem of the inability to integrate existing devices is solved, enabling efficient and low-cost wafer center offset detection.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- SHENYANG JIEJING AUTOMATION EQUIPMENT CO LTD
- Filing Date
- 2025-08-07
- Publication Date
- 2026-06-09
Smart Images
Figure CN224343746U_ABST
Abstract
Description
Technical Field
[0001] This utility model belongs to the technical field of wafer handling equipment, specifically a micro-motion wafer center offset detection device. Background Technology
[0002] Wafer center misalignment refers to the deviation of the wafer center position from the expected target during wafer processing or transport. Wafer center misalignment affects processing accuracy and yield, thus requiring wafer centering correction. Detecting the wafer center misalignment is a prerequisite for wafer alignment; only by detecting the extent of the wafer center misalignment can further measures be taken to compensate for it.
[0003] Existing wafer offset detection equipment works by rotating the wafer around a stage and using a bar sensor to measure several points on the wafer's circumference to fit the coordinates of the center. This requires a separate wafer center offset detection device. Integrating wafer offset detection equipment into a wafer handling robot would significantly reduce process steps and equipment costs. However, integrating the existing rotary wafer center offset detection equipment into the wafer handling robot arm would require the robot arm to rotate, necessitating substantial changes to its mechanical structure, making it less feasible.
[0004] For the reasons mentioned above, there is a need to propose a device that can be integrated into existing wafer handling robots and can complete wafer offset detection without the aid of wafer rotation. Utility Model Content
[0005] To address the shortcomings of existing technologies, this utility model proposes a micro-motion wafer center offset detection device, aiming to solve the problem that existing wafer center offset detection devices cannot be directly integrated into wafer handling robots.
[0006] To achieve the above objectives, the present invention adopts the following technical solution:
[0007] A micro-motion wafer center offset detection device includes a wafer handling robot and a wafer center deviation detection device, wherein the wafer center deviation detection device is fixedly installed on the wafer handling robot;
[0008] The wafer handling robot includes a robotic arm base, on which a wafer handling robotic arm is movably mounted, and the wafer handling robotic arm is equipped with an encoder that provides feedback on the wafer position.
[0009] The wafer center deviation detection device includes a mounting frame, which is a hollow frame structure. A first strip-shaped photoelectric sensor and a second strip-shaped photoelectric sensor are symmetrically mounted in the hollow area of the mounting frame. The wafer handling robot arm can carry the wafer in a linear motion within the hollow area of the mounting frame. The width measurement direction of the first strip-shaped photoelectric sensor and the second strip-shaped photoelectric sensor is perpendicular to the movement direction of the wafer handling robot arm.
[0010] Preferably, the first strip photoelectric sensor consists of a first transmitting end and a first receiving end, with the first transmitting end mounted directly above the first receiving end; the second strip photoelectric sensor consists of a second transmitting end and a second receiving end, with the second receiving end positioned directly below the second transmitting end; and the light emitted by the first transmitting end and the second transmitting end is perpendicular to the wafer surface.
[0011] When the wafer is located at the origin, the projection of its edge onto the first receiving end is within the measurement range of the first strip photoelectric sensor, and the projection onto the second receiving end is within the measurement range of the second strip photoelectric sensor.
[0012] Preferably, the mounting frame includes an upper mounting plate and a lower mounting plate, with a column provided between the upper and lower mounting plates. The first transmitting end and the second transmitting end are mounted on the lower surface of the upper mounting plate, and the first receiving end and the second receiving end are mounted on the upper surface of the lower mounting plate. The lower mounting plate is fixedly mounted on the robotic arm base.
[0013] Preferably, the measurement range of both the first and second strip photoelectric sensors is 3-90 mm.
[0014] Preferably, the wafer handling robot is a dual-arm robot, and the wafer handling robotic arm includes an upper robotic arm and a lower robotic arm. The upper robotic arm and the lower robotic arm are mounted on the upper part of the robotic arm base. Both the upper robotic arm and the lower robotic arm can independently handle wafers and move linearly within the hollow area of the mounting frame. Both the upper robotic arm and the lower robotic arm are equipped with encoders.
[0015] Beneficial effects:
[0016] Compared with the prior art, the present invention can achieve at least the following technical effects:
[0017] 1. This utility model can be integrated into existing wafer handling robots. When the robot's robotic arm moves forward while handling the wafer, the coordinates of the endpoints of two parallel chords on the wafer can be obtained through two sets of bar photoelectric sensors. In this way, the actual center coordinates of the wafer can be obtained, eliminating the need for a separate wafer center offset device and inspection process. This improves inspection efficiency and saves equipment costs.
[0018] 2. This utility model obtains the actual center coordinates of the wafer by using the endpoint coordinates of two parallel chords on the wafer. The wafer handling robot arm only needs to move the wafer forward by 5-10mm to complete the detection of the wafer center deviation, which takes 0.5s to 1s. This time is less than that of traditional wafer alignment devices (about 4 to 6s). Moreover, the algorithm is simple and stable, which further improves the detection efficiency while ensuring the detection accuracy. Attached Figure Description
[0019] Figure 1 This is a schematic diagram of the overall structure of this utility model.
[0020] Figure 2 This is a schematic diagram of the center deviation detection device of this utility model.
[0021] Figure 3 This is a schematic diagram of the detection principle of this utility model.
[0022] In the diagram: 1. Robotic arm base; 2. Upper robotic arm; 3. Lower robotic arm; 4. Mounting frame; 41. Upper mounting plate; 42. Column; 43. Lower mounting plate; 5. First strip photoelectric sensor; 51. First transmitter; 52. Second receiver; 6. Second strip photoelectric sensor; 61. Second transmitter; 62. Second receiver. Detailed Implementation
[0023] The present invention will be further explained below with reference to specific implementation examples.
[0024] Please see Figure 1-2 This utility model proposes a micro-motion wafer center offset detection device, including a wafer handling robot and a wafer center deviation detection device, wherein the wafer center deviation detection device is fixedly installed on the wafer handling robot;
[0025] The wafer handling robot includes a robotic arm base 1, on which a wafer handling robotic arm is movably mounted, and the wafer handling robotic arm is equipped with an encoder that provides feedback on the wafer position.
[0026] The wafer center deviation detection device includes a mounting frame 4, which is a hollow frame structure. A first strip photoelectric sensor 5 and a second strip photoelectric sensor 6 are symmetrically installed in the hollow area of the mounting frame 4. The wafer handling robot arm can carry the wafer in a straight line within the hollow area of the mounting frame 4. The width measurement direction of the first strip photoelectric sensor 5 and the second strip photoelectric sensor 6 is perpendicular to the movement direction of the wafer handling robot arm.
[0027] like Figure 1As shown, the wafer center deviation detection device of this invention is integrated on the wafer handling robot. When the wafer handling robot's wafer handling arm moves forward (R-axis) with the wafer, the center offset of the wafer is detected by two sets of bar photoelectric sensors on the wafer center deviation detection device. This eliminates the need for a dedicated wafer center deviation detection device and the wafer transfer process between the deviation detection device and the wafer handling robot, simplifying the process flow and saving equipment costs.
[0028] like Figure 2 As shown, the two sets of bar photoelectric sensors (first bar photoelectric sensor 5 and second bar photoelectric sensor 6) of the wafer center deviation detection device are symmetrically arranged on the mounting bracket 4. When the wafer handling robot arm carries the wafer to the origin position, the first bar photoelectric sensor 5 and the second bar photoelectric sensor 6 can detect the edge of the wafer, that is, the distance d from the edge of the wafer to the zero point of the bar photoelectric sensor. Since the first bar photoelectric sensor 5 and the second bar photoelectric sensor 6 are symmetrically arranged, let the zero point coordinates of the first bar photoelectric sensor 5 and the second bar photoelectric sensor 6 be (x, y) and (-x, y) respectively. Therefore, the coordinates of the two points on the wafer are (x+d1, y) and (-x-d2, y), where d1 is the first bar photoelectric sensor. The readings of the first strip photoelectric sensor 5 and the second strip photoelectric sensor 6 are d2 and d1 and d2, respectively. When the wafer handling robot arm moves the wafer forward, the encoder on the wafer handling robot arm records the distance l that the wafer moves forward. At this time, the readings of the first strip photoelectric sensor 5 and the second strip photoelectric sensor 6 are d3 and d4, respectively. Then, the coordinates of the points on the two sets of strip photoelectric sensors at the edge of the wafer when the wafer is at the origin are (x+d1, yl) and (-x-d2, yl). Based on the four known coordinates of the points (x+d1, y), (-x-d2, y), (x+d1, yl), and (-x-d2, yl) on the wafer, the actual coordinates of the wafer center can be calculated by a simple geometric algorithm, thereby obtaining the wafer center offset.
[0029] In this embodiment, the first strip photoelectric sensor 5 is composed of a first transmitting end 51 and a first receiving end 52, with the first transmitting end 51 mounted directly above the first receiving end 52. The second strip photoelectric sensor 6 is composed of a second transmitting end 61 and a second receiving end 62, with the second receiving end 62 positioned directly below the second transmitting end 61. The light emitted by the first transmitting end 51 and the second transmitting end 61 is perpendicular to the wafer surface. The projection of the wafer edge onto the first receiving end 52 is within the measurement range of the first strip photoelectric sensor 5, and the projection of the wafer edge onto the second receiving end 62 is within the measurement range of the second strip photoelectric sensor 6.
[0030] like Figure 2As shown, the first strip photoelectric sensor 5 has a through-beam structure with the first emitting end 51. Part of the light emitted by the first emitting end 51 is blocked by the wafer. The projection length of the wafer edge on the first receiving end 52 (the distance d from the edge of the wafer to the zero point of the strip photoelectric sensor) can be obtained through the first receiving end 52. Similarly, the projection length of the wafer edge on the second receiving end 62 can be obtained through the second receiving end 62.
[0031] In this embodiment, the mounting frame 4 is further configured to include an upper mounting plate 41 and a lower mounting plate 43, with a column 42 disposed between the upper mounting plate 41 and the lower mounting plate 43. The first transmitting end 51 and the second transmitting end 61 are mounted on the lower surface of the upper mounting plate 41, and the first receiving end 52 and the second receiving end 62 are mounted on the upper surface of the lower mounting plate 43. The lower mounting plate 43 is fixedly mounted on the robotic arm base 1.
[0032] like Figure 2 As shown, the frame structure of the mounting bracket 4 is displayed, wherein the middle straight portion of the upper mounting plate 41 and the lower mounting plate 43 is perpendicular to the moving direction (R-axis) of the wafer handling robot arm, and the line connecting the center points of the first transmitting end 51 and the second transmitting end 61, as well as the line connecting the center points of the first receiving end 52 and the second receiving end 62, are all perpendicular to the moving direction (R-axis) of the wafer handling robot arm.
[0033] In this embodiment, the measurement range of both the first strip photoelectric sensor 5 and the second strip photoelectric sensor 6 is 3-90mm.
[0034] Based on the mainstream wafer size specification (12 inches), the measurement range of the first strip photoelectric sensor 5 and the second strip photoelectric sensor 6 is set to 3-90mm. Optionally, to facilitate the inspection of wafers of various sizes, a centering and adjusting mechanism can be provided between the first strip photoelectric sensor 5 and the second strip photoelectric sensor 6 to adjust the distance between the two sets of strip photoelectric sensors to accommodate the inspection of wafers of various sizes.
[0035] In this embodiment, the wafer handling robot is further configured as a dual-arm robot, and the wafer handling robotic arm includes an upper robotic arm 2 and a lower robotic arm 3. The upper robotic arm 2 and the lower robotic arm 3 are mounted on the upper part of the robotic arm base 1. Both the upper robotic arm 2 and the lower robotic arm 3 can independently handle wafers and move linearly within the hollow area of the mounting frame 4. Both the upper robotic arm 2 and the lower robotic arm 3 are equipped with encoders.
[0036] In this embodiment, the wafer handling robot is a mainstream dual-arm robot, in which the upper robotic arm 2 and the lower robotic arm 3 can independently complete the wafer handling and center offset detection actions.
[0037] Please see Figure 3The process of solving the actual center coordinates of the wafer using this invention is as follows:
[0038] When the wafer is at the origin, A and B are within the detection range of the first strip photoelectric sensor 5 and the second strip photoelectric sensor 6, respectively. At this time, the readings of the first strip photoelectric sensor 5 and the second strip photoelectric sensor 6 are d1 and d2, respectively. Taking the width measurement direction of the strip photoelectric sensor as the X-axis, the zero point coordinates of the first strip photoelectric sensor 5 and the second strip photoelectric sensor 6 are (x, y) and (-x, y), respectively. Then the coordinates of points A and B are (x+d1, y) and (-x-d2, y), respectively. Let the actual center coordinates of the wafer be (h, k).
[0039] When the wafer handling robot arm moves the wafer forward a distance l, C and D are within the detection range of the first strip photoelectric sensor 5 and the second strip photoelectric sensor 6, respectively. At this time, the readings of the first strip photoelectric sensor 5 and the second strip photoelectric sensor 6 are d3 and d4, respectively. When the wafer is at the origin, the coordinates of points C and D are (x+d1, yl) and (-x-d2, yl), respectively.
[0040] Take the midpoint M of AB and the midpoint N of CD. The coordinates of M (x, y) can be obtained from the coordinates of points A and B. m ,y m Let parameter t be the scaling factor of the vector from M to O relative to the vector from M to N, i.e., ON = t * NM; NM = l, MA = (d1 + d2) / 2 + x, NC = (d3 + d4) / 2 + x.
[0041] Therefore, through OM 2 +MA 2 =ON 2 +NC 2 t can be calculated; let the vector from M to N be (0, d y If M is the vector from M to O, then M is the vector from M to O (0, td). y Then, the coordinates of point O are obtained based on the coordinates of point M.
[0042] In the description of this utility model, the term "multiple" refers to two or more. Unless otherwise explicitly defined, the terms "upper," "lower," "left," "right," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this utility model. The terms "connection," "installation," "fixing," etc., should be interpreted broadly. For example, "connection" can be a fixed connection, a detachable connection, or an integral connection; it can be a direct connection or an indirect connection through an intermediate medium. For those skilled in the art, the specific meaning of the above terms in this utility model can be understood according to the specific circumstances.
[0043] In the description of this utility model, the terms "one embodiment," "some embodiments," "specific embodiment," etc., refer to a specific feature, structure, material, or characteristic described in connection with that embodiment or example, which is included in at least one embodiment or example of this utility model. In this utility model, the 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] The above description is merely a preferred embodiment of this utility model and is not intended to limit the utility model. Various modifications and variations can be made to this utility model by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this utility model should be included within the protection scope of this utility model.
Claims
1. A device for detecting the center offset of a micro-movement wafer, characterized in that, The device includes a wafer handling robot and a wafer center deviation detection device, wherein the wafer center deviation detection device is fixedly mounted on the wafer handling robot. The wafer handling robot includes a robotic arm base (1), on which a wafer handling robotic arm is movably mounted, and the wafer handling robotic arm is equipped with an encoder that provides feedback on the wafer position; The wafer center deviation detection device includes a mounting frame (4), which is a hollow frame structure. A first strip photoelectric sensor (5) and a second strip photoelectric sensor (6) are symmetrically installed in the hollow area of the mounting frame (4). The wafer handling robot arm can carry the wafer in a straight line within the hollow area of the mounting frame (4). The width measurement direction of the first strip photoelectric sensor (5) and the second strip photoelectric sensor (6) is perpendicular to the movement direction of the wafer handling robot arm.
2. The micro-motion wafer center offset detection device according to claim 1, characterized in that, The first strip photoelectric sensor (5) consists of a first transmitting end (51) and a first receiving end (52). The first transmitting end (51) is installed directly above the first receiving end (52). The second strip photoelectric sensor (6) consists of a second transmitting end (61) and a second receiving end (62). The second receiving end (62) is located directly below the second transmitting end (61). The light emitted by the first transmitting end (51) and the second transmitting end (61) is perpendicular to the wafer surface. When the wafer is at the origin, the projection of its edge onto the first receiving end (52) is within the measurement range of the first strip photoelectric sensor (5), and the projection onto the second receiving end (62) is within the measurement range of the second strip photoelectric sensor (6).
3. The micro-motion wafer center offset detection device according to claim 2, characterized in that, The mounting frame (4) includes an upper mounting plate (41) and a lower mounting plate (43). A column (42) is provided between the upper mounting plate (41) and the lower mounting plate (43). The first transmitting end (51) and the second transmitting end (61) are mounted on the lower surface of the upper mounting plate (41). The first receiving end (52) and the second receiving end (62) are mounted on the upper surface of the lower mounting plate (43). The lower mounting plate (43) is fixedly mounted on the robotic arm base (1).
4. The micro-motion wafer center offset detection device according to claim 1, characterized in that, The measurement range of the first strip photoelectric sensor (5) and the second strip photoelectric sensor (6) is 3-90mm.
5. The micro-motion wafer center offset detection device according to claim 1, characterized in that, The wafer handling robot is a dual-arm robot. The wafer handling robotic arm includes an upper robotic arm (2) and a lower robotic arm (3). The upper robotic arm (2) and the lower robotic arm (3) are mounted on the upper part of the robotic arm base (1). Both the upper robotic arm (2) and the lower robotic arm (3) can independently handle wafers and move linearly in the hollow area of the mounting frame (4). Both the upper robotic arm (2) and the lower robotic arm (3) are equipped with encoders.