Wafer centering device

Abstract

The present invention provides a wafer centering device, comprising: a centering cover, the centering cover comprises a cover body with an upward opening, the inner wall diameter of the cover body is gradually increased from bottom to top, the cover body is recessed from the edge to the center along the extension direction of the inner wall to form at least one holding platform for holding the wafer upward and flush with the horizontal plane; a lifting mechanism, the lifting mechanism is fixedly arranged below the centering cover and is used to pass through the centering cover and lift up the wafer placed on the holding surface, the lifting mechanism comprises a driving unit and at least three lifting rods for lifting the wafer; wherein the edge diameter of the holding platform is equal to the diameter of the wafer, and the radially adjacent holding platforms are arranged in a step-by-step manner along the radial inward direction of the cover body. Through the present application, it is avoided that the edge of the thinned wafer is damaged or crushed during centering, so as to reduce production losses, and at the same time simplify the centering steps and improve the efficiency of centering; and the centering of wafers of different sizes is achieved.

Description

Technical Field

[0001] The present invention relates to the technical field of semiconductor equipment, and in particular to a wafer centering device. Background Art

[0002] In the process of wafer manufacturing, automated equipment is usually used to implement the process flow. For example, in some occasions where wafers need to be transferred, robots are often used to transfer wafers. When using automated equipment to implement processes on wafers, the position coordinates of the wafer are more critical. Whether the position coordinates of the wafer are accurate determines whether the automated equipment can smoothly implement the process flow on the wafer. If the position coordinates of the wafer deviate, the automated equipment will not be able to implement the operation correctly, and may even cause serious errors in the wafer process (Recipe), which will lead to process errors in the chip area on the upper surface of the wafer and cause the entire wafer to be scrapped. Therefore, before the automated equipment implements the process flow on the wafer, the wafer needs to be centered to determine the position coordinates of the center of the wafer.

[0003] After searching, the applicant found that a Chinese invention patent with publication number CN112635380A discloses a wafer centering device. In this prior art, a first centering adjustment member and a second centering adjustment member arranged at intervals along a predetermined direction and a first driving mechanism are provided. The first driving mechanism drives the first centering adjustment member and the second centering adjustment member to move synchronously closer to or farther from each other, so that the first centering adjustment member and the second centering adjustment member jointly clamp the wafer, thereby centering the wafer.

[0004] First, the prior art cannot guarantee that the wafer will not be damaged during the centering process, especially for wafers that have undergone a thinning process, as the wafer will become brittle after thinning. The prior art adopts a centering method in which both sides clamp the wafer together, which can easily cause damage to the edge of the wafer, or even crush the entire wafer, thereby increasing production losses. Secondly, the prior art requires a first drive mechanism to drive the first centering adjustment member and the second centering adjustment member to approach synchronously to clamp the wafer, and then the second drive mechanism is used to lift the wafer. Therefore, the entire centering process is complicated, reducing production efficiency.

[0005] In view of this, it is necessary to improve the wafer centering device in the prior art to solve the above problems. Summary of the invention

[0006] The object of the present invention is to provide a wafer centering device to solve the defects of the wafer centering device in the prior art, especially to avoid the edge of the thinned wafer being damaged or crushed during centering, so as to reduce production losses, and at the same time simplify the centering steps and improve the centering efficiency.

[0007] To achieve the above object, the present invention provides a wafer centering device, comprising:

[0008] A centering cover, the centering cover comprises a cover body with an upward opening, the inner wall diameter of the cover body is gradually increased from bottom to top, and the cover body is concave from the edge to the center along the extension direction of the inner wall to form at least one holding platform for holding the wafer upward and flush with the horizontal plane;

[0009] A lifting mechanism, the lifting mechanism is fixedly arranged below the centering cover and is used to pass through the centering cover and lift up the wafer placed on the supporting surface, the lifting mechanism includes a driving unit and at least three lifting rods for lifting the wafer;

[0010] The edge diameter of the holding platform is equal to the diameter of the wafer, and the radially adjacent holding platforms are arranged to be gradually lowered along the radial inward direction of the cover body.

[0011] As a further improvement of the present invention, the mandrels are distributed in geometric symmetry and the centers of geometric symmetry coincide with the projection of the center of the centering cover on the horizontal plane, and the top ends of the mandrels are located in the same horizontal plane.

[0012] As a further improvement of the present invention, a suction cup for adsorbing the lower surface of the wafer is arranged at the top end of the ejector rod.

[0013] As a further improvement of the present invention, it also includes: a fixing member for stabilizing the driving unit, the fixing member includes a horizontal section parallel to the horizontal plane and a vertical section perpendicular to the horizontal plane, the horizontal section is fixed on the horizontal plane, and the vertical section fixes the driving unit.

[0014] As a further improvement of the present invention, the holding surface is embedded with a plurality of sensors for sensing the wafer, and the sensors are electrically connected to the driving unit and the suction cup.

[0015] As a further improvement of the present invention, the cover body is provided with a notch for the robot arm to clamp the wafer.

[0016] As a further improvement of the present invention, at least three support rods for fixing and supporting the centering cover are arranged around the driving unit.

[0017] Compared with the prior art, the present invention has the following beneficial effects:

[0018] First, in the present application, the centering hood includes a hood body with an upward opening, the inner wall diameter of the hood body is gradually increased from bottom to top, the hood body is recessed from the edge to the center along the extension direction of the inner wall to form at least one holding platform for holding the wafer upward and flush with the horizontal plane, and the edge diameter of the holding platform is equal to the diameter of the wafer, the wafer slides onto the holding platform through the inner wall to achieve centering, and a lifting mechanism is fixedly arranged below the centering hood, the lifting mechanism includes a lifting rod for lifting the wafer upward, thereby avoiding the situation where the edge of the thinned wafer is damaged or crushed due to the horizontal clamping force during centering, thereby reducing production consumption, reducing centering steps, and improving centering efficiency; secondly, by setting at least two or more holding platforms of different sizes, the same wafer centering device can be used to center wafers of different sizes, thereby improving the applicability and convenience of the wafer centering device. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 A three-dimensional diagram of a wafer centering device disclosed in the present invention;

[0020] Figure 2 is a three-dimensional diagram of the centering cover of the present invention;

[0021] Figure 3 for Figure 2 A top view of the centering hood shown;

[0022] Figure 4 A three-dimensional diagram of a jacking mechanism in the present invention from one viewing angle;

[0023] Figure 5 A three-dimensional diagram of the jacking mechanism of the present invention from another perspective;

[0024] Figure 6 It is a top view of the lifting mechanism in the present invention. DETAILED DESCRIPTION

[0025] The present invention is described in detail below in conjunction with the various embodiments shown in the accompanying drawings, but it should be noted that these embodiments are not limitations of the present invention, and any equivalent transformations or substitutions in functions, methods, or structures made by ordinary technicians in the field based on these embodiments are all within the scope of protection of the present invention.

[0026] It should be noted that when an element is considered to be "connected" to another element, it may be directly connected to another element or there may be a centering element at the same time. Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those generally understood by those skilled in the art of the technical field of the present invention. The terms used in the specification of the present invention herein are only for the purpose of describing specific embodiments and are not intended to limit the present invention. The term "and / or" used herein includes any and all combinations of one or more related listed items.

[0027] It should be understood that the orientation or position relationship indicated by terms such as "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential", "positive direction", "negative direction", etc. are based on the orientation or position relationship shown in the accompanying drawings, and are only for the convenience of describing the technical solution and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the technical solution.

[0028] Ginseng Figures 1 to 6 A specific embodiment of a wafer centering device of the present invention is shown. The wafer centering device performs centering on wafers of different sizes, especially on wafers that have undergone a thinning process, to protect the wafers to the maximum extent to avoid damage to the wafers. Figure 1 As shown, in this embodiment, the wafer centering device includes: a centering cover 10 and a lifting mechanism 20 disposed below the centering cover 10. The centering cover 10 is used to accommodate and center the wafer, and the lifting mechanism 20 is used to lift the wafer that has been centered in the centering cover 10 and transport it to the next station through a robot arm.

[0029] Combination Figures 2 to 3As described, in the present embodiment, the centering cover 10 includes a funnel-shaped cover body 11, the cover body 11 has an upward opening and the diameter of the inner wall 111 of the cover body 11 is gradually increased from bottom to top (that is, the cover body 11 is axially expanded upward along the axial direction). The cover body 11 is recessed from the edge to the center in the extension direction of the inner wall 111 to form at least one holding platform 12, and the holding platform 12 is used to hold the wafer upward and the holding platform 12 is flush with the horizontal plane. The edge diameter of the holding platform 12 is equal to the diameter of the wafer to be centered. Specifically illustrated as shown in the accompanying drawings, in the present embodiment, the cover body 11 is recessed from the edge to the center in the extension direction of the inner wall 111 to form two holding platforms 12, which include a first holding platform 121 and a second holding platform 122 located radially inside the first holding platform 121. Among them, the edge diameter of the first holding platform 121 is larger than the diameter of the second holding platform 122. The edge diameter of the first holding platform 121 is 8 inches for centering 8-inch wafers, and the edge diameter of the second holding platform 122 is 6 inches for centering 6-inch wafers. The second holding platform 122 is set lower than the first holding platform 121, so that a wafer centering device can perform centering on wafers of different sizes, increasing the application range of the wafer centering device and improving the adaptability and convenience of the device. Further, in the specific implementation of the present invention, there is no specific restriction on the number of holding platforms 122 formed. It is only necessary that two radially adjacent holding platforms 122 are arranged in a step-by-step manner along the radial direction of the cover body 11 so as not to cause interference. At the same time, there is no specific restriction on the edge size of the holding platform 122. It is only necessary that the edge diameter of the holding platform 122 is equal to the diameter of the wafer to be centered. The specific value and combination of the edge diameter of the holding platform 122 can be obtained according to actual usage.

[0030] Further, Figures 2 to 3 As shown, the centering cover 10 also includes a notch 13 provided on the cover body 11 and a fixing block 14 fixed to the lower end of the cover body 11. When the wafer is centered through the centering cover 10, the robot arm can clamp the lifted wafer through the notch 13. The fixing block 14 is provided with a plurality of mounting holes 141 and a through hole 142. The inner wall 111 of the cover body 11 forms an angle α with the supporting platform 12. The inner wall 111 of the cover body 11 is used to guide the wafer to the supporting platform 12 smoothly and safely. The value range of the angle α is greater than 0° and less than 90°. Preferably, when the angle α is selected to be 60°, the guiding effect of the inner wall 111 is the best. When the wafer slides to the supporting platform 12, the center A of the centering cover 10 coincides with the projection of the center of the wafer on the horizontal plane, and the centering is completed.

[0031] Ginseng Figures 4 to 6As shown, a lifting mechanism 20 is fixedly arranged below the centering cover 10, and the lifting mechanism 20 includes: a bottom plate 21, a driving unit 23 arranged on the bottom plate 21 and arranged vertically upward. In this embodiment, the driving unit 23 is a cylinder, and preferably, the cylinder is a servo cylinder. The driving unit 23 includes a body 231 and an actuator rod 232, wherein a top plate 24 is fixedly arranged horizontally on the top of the actuator rod 232, and the actuator rod 232 is used to stably support the top plate 24 to perform the rising and falling actions. Four top rods 25 for lifting the wafer upward are vertically protruded upward on the upper surface of the top plate 24. It should be noted that in this embodiment, four top rods 25 are protruded on the upper surface of the top plate 24, but when the present invention is actually implemented, the number of the top rods 25 is greater than or equal to three to stably support the lifted wafer, because when more than three supporting points are provided for the wafer, the wafer is not easy to fall.

[0032] Specifically, combined Figure 4 and Figure 5 As shown, a plurality of fixing holes 211 are provided on the bottom plate 21, and the bottom plate 21 is fixed to a horizontal plane through the fixing holes 211 to ensure that the wafer centering device is arranged vertically as a whole, thereby avoiding affecting the stability of the wafer after being lifted up. The lifting mechanism 20 also includes a fixing member 26 for fixing and supporting the driving unit 23. The fixing member 26 includes a horizontal section 262 parallel to the bottom plate 21 and a vertical section 261 perpendicular to the bottom plate 21, wherein the horizontal section 262 is fixed to the upper surface of the bottom plate 21, and the vertical section 261 is fixed to the body 231 of the driving unit 23, and is used to support the body 231 and keep the actuator 232 vertically upward to lift the wafer, thereby avoiding the wafer centering device after long-term use. The lifting angle of the actuator 232 is offset to affect the accuracy of the wafer centering. The driving unit 23 includes two actuator rods 232 for lifting the top plate 24. The top plate 24 is in a geometrically symmetrical butterfly shape. The symmetry centers of the two actuator rods 232 coincide with the projection of the symmetry center of the top plate 24 on the horizontal plane, so as to ensure that the actuator rods 232 are uniformly stressed when lifting the top plate 24, thereby ensuring that the top plate 24 rises and falls in the vertical direction. Three support rods 22 are arranged around the driving unit 23. The top ends of the support rods 22 are fixed to the centering cover 10 through the mounting holes 141. The support rods 22 are used to lift the centering cover 10 upward.

[0033] Further, combined with Figure 6As shown, a push rod 25 protrudes vertically from the top plate 24, and the four push rods 25 are distributed in geometric symmetry, and the geometric center B coincides with the projection of the center A of the centering cover 10 on the horizontal plane. At the same time, the geometric center B of the four push rods 25 also coincides with the projection of the center of the wafer on the horizontal plane. Therefore, when the push rods 25 lift the wafer upward, the upward support force provided by the push rods 25 to the wafer is distributed in geometric symmetry with the center of the wafer as the symmetry center, so that the force distribution of the wafer in the vertical direction is uniform. Since the mass of the wafer itself is evenly distributed, it is effectively avoided that the wafer is damaged or broken due to uneven force during the lifting process.

[0034] Combination Figures 1 to 6, the specific implementation method of the present invention is described in detail. Before placing the wafer, the push rod 25 needs to be lifted by the driving unit 23. After the push rod 25 is fully lifted, the wafer to be centered is placed on the push rod 25, and the driving unit 23 slowly lowers the execution rod 232 to ensure that the wafer is not damaged. Since the center of the wafer is not centered, the wafer contacts the inner wall 111 in the direction deviating from the center A of the centering cover 10, so that the inner wall 111 applies a reverse force to the wafer. Therefore, in the process of the push rod 25 driving the wafer to descend, the inner wall 111 continues to apply a horizontal force to the wafer to correct the wafer until the wafer falls onto the supporting platform 12. It should be noted here that in order to prevent the wafer from being damaged in the process of falling onto the holding platform 12, as a further extension of the present embodiment, a flexible material is provided on the surface of the inner wall 111, and the flexible material is used to make the wafer in flexible contact with the inner wall 111 of the centering cover 10, thereby protecting the wafer at the contact point with the inner wall 111 and ensuring that the wafer is not scratched or damaged. The wafer that falls onto the holding platform 12 is centered, and at this time, the actuator rod 232 of the drive unit 23 passes through the through hole 142 and lifts the wafer vertically upward. It should be noted that, as a further extension of the present invention, the top end of the push rod 25 (i.e., the contact position between the push rod 25 and the wafer) is provided with a suction cup (not shown) for adsorbing the lower surface of the wafer. The suction cup is connected to the suction channel (not shown) contained in the ejector pin, and is connected to the negative pressure generating device (not shown) through the suction channel. The negative pressure generating device creates a negative pressure environment in the suction cup and uses the atmospheric pressure to adsorb the suction cup to the lower surface of the wafer, thereby avoiding interference from external environmental factors on the wafer during the lifting process, so as to avoid the wafer from being offset, tilted or falling in the horizontal direction, thereby improving the centering accuracy of the wafer. Further, during the falling process of the aforementioned wafer, the suction cup is not adsorbed to the lower surface of the wafer to ensure that the wafer can be corrected in the horizontal direction during the falling process along the inner wall 111. The aforementioned lower surface of the wafer refers to the substrate of the wafer and is opposite to the chip area formed by processes such as photolithography, etching, diffusion, and film formation. The robot arm clamps the wafer lifted by the ejector pin 25 through the notch 13 set on the centering cover 10 and performs the next process. At this time, the ejector pin 25 is lowered and retracted, waiting for the next wafer to be centered. As a further extension of the present invention, in order to realize the automation of lifting the wafer, a sensor (not shown) for sensing the wafer is embedded in a ring at the position in contact with the wafer on the holding platform 12. The sensor (not shown) is electrically connected to the drive unit and the suction cup (not shown). When the sensor (not shown) senses that the wafer has fallen onto the holding platform 12, the sensor (not shown) transmits the captured information to the drive unit 23 and the suction cup (not shown). At this time, the drive unit 23 drives the actuator rod 232 to lift upward, and the suction cup (not shown) adsorbs the lower surface of the wafer to complete the wafer lifting operation.

[0035] The series of detailed descriptions listed above are only specific descriptions of feasible implementation methods of the present invention. They are not intended to limit the scope of protection of the present invention. Any equivalent implementation methods or changes that do not deviate from the technical spirit of the present invention should be included in the scope of protection of the present invention.

[0036] It will be apparent to those skilled in the art that the invention is not limited to the details of the exemplary embodiments described above and that the invention can be implemented in other specific forms without departing from the spirit or essential features of the invention. Therefore, the embodiments should be considered exemplary and non-limiting in all respects, and the scope of the invention is defined by the appended claims rather than the foregoing description, and it is intended that all variations falling within the meaning and scope of the equivalent elements of the claims be included in the invention. Any reference numeral in a claim should not be considered as limiting the claim to which it relates.

[0037] In addition, it should be understood that although the present specification is described according to implementation modes, not every implementation mode contains only one independent technical solution. This description of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment may also be appropriately combined to form other implementation modes that can be understood by those skilled in the art.

Claims

1. A wafer centering device performs a centering operation on a wafer after a thinning process. It is characterized in that include: A centering cover, the centering cover comprises a cover body with an upward opening, a fixing block fixed to the lower end of the cover body, the inner wall diameter of the cover body is gradually increased from bottom to top, the cover body is recessed from the edge to the center in the extension direction of the inner wall to form at least one holding platform for holding the wafer upward and flush with the horizontal plane, and the holding platform forms a holding surface for holding the wafer; A lifting mechanism, the lifting mechanism is fixedly arranged below the centering cover and is used to pass through the centering cover and lift up the wafer placed on the supporting surface, the lifting mechanism includes a driving unit and at least three lifting rods for lifting the wafer; The edge diameter of the holding platform is equal to the diameter of the wafer, the radially adjacent holding platforms are arranged to be gradually lowered along the radial inward direction of the cover body, the cover body is provided with a notch for the robot arm to clamp the wafer, and the center of the fixed block forms a central notch connected to the notch; The driving unit includes a main body and an actuator rod, a top plate is laterally fixed on the top of the actuator rod, the top rod is vertically protruded upward from the upper surface of the top plate, the symmetry center of the actuator rod coincides with the projection of the symmetry center of the top plate on the horizontal plane, and the top rod passes through the fixed block in the vertical direction.

2. The wafer centering device according to claim 1, It is characterized in that The push rods are distributed in geometric symmetry, and the centers of geometric symmetry coincide with the projections of the center points of the centering covers on the horizontal plane, and the top ends of the push rods are located in the same horizontal plane.

3. The wafer centering device according to claim 2, It is characterized in that The top end of the ejector rod is provided with a suction cup for adsorbing the lower surface of the wafer.

4. The wafer centering device according to claim 1, It is characterized in that Also includes: A fixing member for stabilizing the driving unit, wherein the fixing member comprises a horizontal section parallel to the horizontal plane and a vertical section perpendicular to the horizontal plane, wherein the horizontal section is fixed on the horizontal plane, and the vertical section fixes the driving unit.

5. The wafer centering device according to claim 3, It is characterized in that The holding surface is embedded with a plurality of sensors for sensing wafers, and the sensors are electrically connected to the driving unit and the suction cup.

6. The wafer centering device according to claim 1, It is characterized in that At least three support rods for fixing and supporting the centering cover are arranged around the driving unit.

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