A wafer alignment method

Abstract

The invention discloses a wafer alignment method, including: a support member moves upward; a fork clamps a wafer and adjusts the height position of the wafer; the fork drives the wafer to move toward a detection slot along a first direction; the fork drives the wafer to move downward, and the fork releases the clamping of the wafer; the flatness of the wafer is detected by a pressure value collected by a pressure sensor; when the flatness of the wafer is qualified, the fork continues to move downward until the fork is carried by a support surface; the support member moves downward until the wafer is carried on a rotating surface, and the rotating surface adsorbs the wafer; the rotating platform drives the wafer to rotate synchronously, and the detection slot pre-aligns the wafer; the rotating surface stops adsorption, and the support member moves upward until the mobile wafer is separated from the supporting surface; the flatness of the wafer is detected by the pressure value collected by the pressure sensor; when the flatness of the wafer is qualified, the fork carries the wafer away from the alignment device. The wafer on the fork is transferred to the rotating platform for alignment, and the flatness of the wafer is detected before and after alignment.

Description

Technical Field

[0001] The present invention relates to the technical field of wafer transmission equipment, and in particular to a wafer alignment method. Background Art

[0002] During the wafer processing, wafer transfer equipment (EFEM / Sorter) is usually used to transfer wafers between different process machines. The wafer transfer equipment includes a robot and an alignment device. When the wafer is transferred by the wafer transfer equipment, the robot is used to take the wafer out of the wafer box and place it on the pre-alignment mechanism for alignment. Usually, the end effector of the robot uses a Y-shaped clamping fork, which can clamp a wafer and place the wafer on the raised rotating platform of the pre-alignment mechanism for alignment.

[0003] The rotating platform fixes the wafer by adsorption. If the wafer is not flat enough or has abnormal warping, the rotating platform will not adsorb the wafer firmly, which will cause the wafer to detach from the rotating platform and affect alignment, and also affect subsequent wafer processing. However, the clamping fork does not have high requirements for the flatness of the wafer. Even if there is a warped wafer, it can be transported by the clamping fork. This results in the clamping fork being unable to detect the warping problem of the wafer when transporting the wafer for alignment, which may affect the wafer alignment. Summary of the invention

[0004] In order to overcome the above-mentioned shortcomings, the purpose of the present invention is to provide a wafer alignment method, which can transfer the wafer on the fork to a rotating platform for alignment, and perform flatness detection on the wafer before and after alignment, to ensure that the wafer placed on the rotating platform meets the flatness requirements and can be firmly adsorbed by the rotating platform.

[0005] In order to achieve the above purpose, the technical solution adopted by the present invention is: a wafer alignment method, based on a wafer alignment device to align the wafer transported by a wafer fork, the wafer alignment device comprising:

[0006] A pre-alignment mechanism, the pre-alignment mechanism comprises a rotating platform, the wafer fork approaches or moves away from the rotating platform along a first direction in a horizontal plane, and a detection groove for inserting a wafer edge is provided on one side of the rotating platform;

[0007] The transfer mechanism includes two support members located on both sides of the rotating platform, the two support members are arranged at intervals in a horizontal plane along a second direction perpendicular to the first direction, each support member includes a support surface located at the same height position and capable of carrying a wafer, each support surface is provided with at least one pressure sensor for obtaining a pressure value on the support surface, and the two support members can move up and down synchronously; the wafer alignment method includes:

[0008] The support member moves upward until the height of the support surface is higher than the height of the rotating surface of the rotating platform, and the height difference between the support surface and the rotating surface is greater than the thickness of the fork;

[0009] The wafer is clamped by a fork and the height position of the wafer is adjusted until the lower surface of the wafer is located above the support surface and the lower groove surface of the detection groove, and the upper surface of the wafer is located below the upper groove surface of the detection groove;

[0010] The wafer is driven by the fork to move along the first direction toward the inspection slot until the central axis of the wafer coincides with the central axis of the rotating platform;

[0011] The fork drives the wafer downward until the lower surface of the wafer abuts against the supporting surface, and the fork releases the wafer;

[0012] The flatness of the wafer is detected by using the maximum difference of the pressure values ​​collected by the pressure sensor;

[0013] When the flatness test of the wafer is qualified, the fork continues to move downward until it moves to a position where the upper end surface of the fork is lower than the height of the supporting surface, and the fork moves out in the horizontal plane in a direction away from the test slot;

[0014] The support member moves downward until it moves to a position where the support surface is lower than the height of the rotating surface, the wafer is carried on the rotating surface, and the rotating surface absorbs the wafer;

[0015] The rotating platform drives the wafer to rotate synchronously, and the inspection slot pre-aligns the wafer;

[0016] After pre-alignment, the rotating surface stops adsorbing the wafer, and the support moves upward until it moves to a height position where the support surface is higher than the rotating surface, and the wafer is carried on the support surface;

[0017] The flatness of the wafer is detected by using the maximum difference of the pressure values ​​collected by the pressure sensor;

[0018] When the flatness test of the wafer is qualified, the wafer on the fork transport support surface leaves the alignment device.

[0019] Specifically, the flatness detection of the wafer based on the maximum difference of the pressure values ​​collected by the pressure sensor includes:

[0020] Find the maximum and minimum pressure values ​​at the same time;

[0021] Calculate the difference between the maximum and minimum values ​​to get the maximum difference;

[0022] Determine whether the maximum difference is less than the set threshold;

[0023] If so, the wafer flatness test is qualified; if not, the wafer is judged to be abnormal and an abnormal alarm signal is issued.

[0024] Furthermore, at least two pressure sensors are evenly spaced apart on the support surface along the second direction to form a detection portion, and at least two detection portions are disposed on the support surface along the first direction.

[0025] Furthermore, the support member includes a support member body, on which friction blocks corresponding to the pressure sensors are arranged, the upper end surface of the friction blocks is the support surface, and the upper end surface of the friction blocks is not lower than the upper end surface of the support member body.

[0026] Furthermore, the transfer mechanism further includes a linear module, which is connected to two support members via a connecting member, and the linear module is used to drive the support members to move up and down, the connecting member includes two connecting parts and a fixing part located between the two connecting parts, and the support member is arranged on a side of the connecting part away from the fixing part;

[0027] The height position of the upper end surface of the fixing portion is lower than the height position of the supporting surface, and the height difference between the upper end surface of the fixing portion and the supporting surface is not less than the thickness of the slice fork.

[0028] Furthermore, the minimum distance between the two connecting parts in the second direction is not less than the width of the fork, and the upper end surface of the connecting part is not higher than the height position of the supporting surface.

[0029] Furthermore, the minimum spacing between the two connecting parts in the second direction is smaller than the width of the slice fork, the upper end surface of the connecting part is lower than the height position of the supporting surface, and the height difference between an upper end surface located at a higher position between the upper end surface of the connecting part and the upper end surface of the fixing part and the supporting surface is not less than the thickness of the slice fork.

[0030] Furthermore, the detection slot is arranged on a vertical plane passing through the central axis of the detection platform, and the two support members are symmetrically arranged on both sides of the vertical plane.

[0031] Furthermore, the transfer mechanism also includes a limit column, which is used to limit the rising distance of the support member.

[0032] Furthermore, a detection element is disposed in the detection groove, and the detection element can emit vertical detection light. The edge of the wafer adsorbed on the rotating platform can be inserted into the detection groove and detected by the detection element. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 A schematic diagram of the structure of a wafer alignment device according to an embodiment of the present invention;

[0034] Figure 2 A schematic diagram of the structure of a wafer alignment device according to another embodiment of the present invention from another angle;

[0035] Figure 3 It is a structural schematic diagram of a switching mechanism in one embodiment of the present invention;

[0036] Figure 4 A top view of a wafer alignment device according to another embodiment of the present invention;

[0037] Figure 5 This is a schematic diagram of the moving state of a wafer fork transporting a wafer in one embodiment of the present invention;

[0038] Figure 6 This is a schematic diagram of a state where a supporting surface carries a wafer in one embodiment of the present invention;

[0039] Figure 7 It is a schematic diagram of the state of the blade fork away from the detection component in one embodiment of the present invention;

[0040] Figure 8 Schematic diagram of a state where a rotating platform carries a wafer in one embodiment of the present invention. DETAILED DESCRIPTION

[0041] The preferred embodiments of the present invention are described in detail below in conjunction with the accompanying drawings so that the advantages and features of the present invention can be more easily understood by those skilled in the art, thereby making a clearer and more definite definition of the protection scope of the present invention.

[0042] A wafer alignment device according to an embodiment of the present invention is used to align a wafer 5 carried by a fork 1, wherein the fork 1 is a clamping fork, which is Y-shaped and includes a root and two fingers, and clamps the wafer 5. The fork 1 is connected to a manipulator, and the manipulator drives the fork 1 to move, and the fork 1 is used to carry the wafers 5 in the wafer loading mechanism one by one to the wafer alignment device for alignment.

[0043] See attached Figure 1 and attached Figure 2 As shown, the wafer alignment device includes a pre-alignment mechanism 3 and a transfer mechanism 2 , wherein the pre-alignment mechanism 3 is used for aligning the wafer 5 , and the transfer mechanism 2 is used for transferring the wafer 5 between the fork 1 and the pre-alignment mechanism 3 and performing flatness detection on the wafer 5 .

[0044] The pre-alignment mechanism 3 includes a rotating platform 31, which is used to carry the wafer 5 and drive the wafer 5 to rotate. The transfer mechanism 2 transfers the wafer 5 between the fork 1 and the rotating platform 31. The transfer mechanism 2 can lift the wafer 5 carried by the fork 1 and drive the wafer 5 to move only in the vertical direction (Z direction) to place the wafer 5 on the transfer mechanism 2 on the rotating platform 31. During this process, the center of the wafer 5 will not deviate in the horizontal plane and only move up and down in the vertical direction. A detection groove 32 for inserting the edge of the wafer 5 is provided on one side of the rotating platform, and the detection groove is used for the alignment of the wafer 5.

[0045] The rotating platform 31 is a cylindrical structure, and the rotating platform 31 can rotate along its own axis. The upper end surface of the rotating platform 31 is a rotating surface 311, and the wafer 5 can be fixed on the rotating surface 311 and rotated under the drive of the rotating surface 311. The rotating surface 311 is provided with an adsorption port, and the adsorption port can generate negative pressure to adsorb the wafer 5 placed on the rotating surface 311. When the wafer 5 is placed on the rotating surface 311, the rotating platform 31 and the wafer 5 are coaxially arranged, and the center of the rotating surface 311 is located on the central axis of the wafer 5.

[0046] See attached Figure 2 and attached Figure 3 As shown, the transfer mechanism 2 includes a support member 21 and a linear module 22. Two support members 21 are provided. The fork approaches or moves away from the rotating platform 31 along the Y direction (first direction) to transport the wafer to the top of the rotating platform 31. The two support members 21 are arranged at intervals along the X direction (second direction) and are located on both sides of the rotating platform. The two support members 21 can move up and down synchronously under the drive of the linear module 22. The two support members 21 respectively have support surfaces 211 located at the same height position, and the support surfaces 211 are used to support the lower surface of the wafer 5.

[0047] In this embodiment, a switching mechanism 2 is added, and the switching mechanism 2 uses two support members 21, and a distance is left between the two support members 21. This distance forms a space for the rotating platform 31, and the support member 21 will not interfere with the rotating platform 31 when moving up and down.

[0048] At least one pressure sensor 7 is disposed on each of the support surfaces 211, and the pressure sensor 7 is used to obtain a pressure value at a corresponding position on the support surface 211. The flatness of the wafer 5 can be detected based on the pressure value collected by the pressure sensor 7.

[0049] The wafer alignment method using the wafer alignment device includes:

[0050] Step 101 , the support member 21 moves upward until the height of the support surface 211 is higher than the height of the rotating surface 311 , and the height difference between the support surface 211 and the rotating surface 311 is greater than the thickness of the fork 1 .

[0051] During this process, the two support members 21 move upward synchronously, and the height difference between the support surface 211 and the rotating surface 311 is greater than the thickness of the fork 1, providing sufficient space for the subsequent downward movement of the fork 1 to prevent the fork 1 from touching the rotating platform 31 when moving downward.

[0052] Step 102 , the fork 1 clamps the wafer 5 and adjusts the height position of the wafer 5 until the lower surface of the wafer 5 is located above the support surface 211 and the lower groove surface of the detection groove 32 , and the upper surface of the wafer 5 is located below the upper groove surface of the detection groove 32 .

[0053] At this time, the height positions of the support member 21 and the wafer 5 are shown in the attached Figure 5 As shown, only when the wafer 5 reaches this height position, the edge of the subsequent wafer 5 can be inserted into the detection groove 32 for pre-alignment.

[0054] Step 103 : The wafer fork 1 drives the wafer 5 to move toward the pre-alignment mechanism 3 in a horizontal plane until the central axis of the wafer 5 coincides with the central axis of the rotating platform 31 .

[0055] Fork 1 along the Figure 5 Move in the direction of the hollow arrow.

[0056] Step 104 : The fork 1 drives the wafer 5 to move downward until the lower surface of the wafer 5 abuts against the supporting surface 211 , and the fork 1 releases the clamping of the wafer 5 .

[0057] At this time, the relative positions of the fork and the support surface 211 are shown in the attached Figure 6 As shown, the wafer 5 is now supported by the support surface 211, and the clamping of the wafer 5 by the fork 1 can be released. In this way, the fork 1 will not be able to drive the wafer to continue moving.

[0058] Step 105 , performing flatness detection on the wafer using the maximum difference of the pressure values ​​collected by the pressure sensor.

[0059] At this time, the wafer 5 is already supported on the support surface 211. If the wafer 5 is flat, the pressure values ​​collected by all pressure sensors should be the same. Before the wafer is placed on the rotating platform, a flatness test of the wafer is performed to ensure that the wafer placed on the rotating platform meets the flatness requirements and can be tightly adsorbed by the rotating platform.

[0060] Step 106 , when the flatness test of the wafer 5 is qualified, the fork 1 continues to move downward until the upper end surface of the fork 1 is lower than the rotating surface 311 , and then the fork 1 moves out in the horizontal plane in a direction away from the pre-alignment mechanism 3 .

[0061] At this time, the wafer flatness meets the requirements to ensure that the rotating platform can absorb the wafer. When the fork 1 moves to a height lower than the support surface 211, the wafer 5 has been placed on the support surface 211. At this time, the fork 1 no longer supports the wafer 5 and the fork 1 can be pulled out. When the fork 1 moves away from the pre-alignment mechanism 3 in the horizontal plane, the moving route is the same as the moving route in the horizontal plane toward the pre-alignment mechanism in step 103. See the attached Figure 7 As shown, the slice fork moves in the direction of the hollow arrow in the figure. At this time, the slice fork 1 has been moved out and the wafer 5 has been carried on the supporting surface 211.

[0062] Step 107 , the support member 21 moves downward until the support surface 211 is lower than the rotating surface 311 . At this time, the wafer 5 is supported on the rotating surface 311 , and the rotating surface 311 absorbs the wafer 5 .

[0063] See attached Figure 8 As shown, at this time, the wafer 5 has been carried on the rotating surface 311, and the edge of the wafer 5 has been inserted into the detection groove 32, and the wafer 5 and the rotating platform 31 are coaxially arranged at this time. Because the wafer has undergone the flatness detection in step 105, the wafer placed on the rotating platform in this step meets the flatness requirements and can be adsorbed by the rotating platform.

[0064] Step 108 : The rotating platform 31 drives the wafer 5 to rotate synchronously, and the detection component starts to pre-align the wafer 5 .

[0065] In step 101-step 108, the wafer 5 on the fork 1 is transported by two support members 21 that move up and down. The wafer 5 can be transferred between the fork 1 and the rotating platform 31 only by lifting and lifting the support surface 211, and the center of the wafer 5 is kept in the horizontal plane without deviation. At the same time, compared with the prior art, the transfer mechanism directly places the wafer on the fork on the rotating platform. The alignment method may cause the wafer to be unable to be adsorbed by the rotating platform due to the warping of the wafer. In this embodiment, through step 105, the transfer mechanism first performs a flatness test on the wafer before placing the wafer on the rotating platform to ensure that the flatness of the wafer placed on the rotating platform is qualified. At this time, the adsorption-type rotating platform can firmly adsorb the wafer to prevent the wafer from falling during rotation.

[0066] Step 109 , after pre-alignment, the rotating surface 311 stops adsorbing the wafer 5 , and the support member 21 moves upward until the support surface 211 is higher than the rotating surface, and the wafer is supported on the support surface.

[0067] At this time, the wafer is separated from the rotating surface, and the rotating surface no longer has the ability to adsorb the wafer.

[0068] Step 110 , performing flatness detection on the wafer using the maximum difference of the pressure values ​​collected by the pressure sensor.

[0069] After pre-alignment, the flatness is tested for the second time using the pressure value collected by the pressure sensor. If the wafer 5 is flat, the pressure values ​​on all the pressure sensors should be the same. Because the wafer after pre-alignment has been rotated by the rotating platform, although the axis of the wafer has not moved, the wafer has rotated a certain angle, and the position corresponding to the support surface has changed. However, the position of the wafer warping is random, so after the wafer is pre-aligned (rotated), the wafer flatness is tested again. Two flatness tests on different positions of the wafer make the test more comprehensive.

[0070] Step 111: When the flatness of the wafer passes the test, the wafer on the wafer fork transport support surface leaves the wafer alignment device.

[0071] The slice fork in step 111 and the slice fork in step 102 may be the same slice fork or different slice forks.

[0072] In this embodiment, the wafer is accurately transferred through the transfer mechanism, and a pressure sensor is set on the bearing surface, so that the support surface can transfer the wafer while the flatness of the wafer can be detected. During the wafer alignment process, before and after the wafer pre-alignment, the support member is respectively against the wafer to perform flatness detection on the front and back sides of the wafer to achieve flatness detection at different positions of the wafer, thereby improving the comprehensiveness and accuracy of the detection. The wafer flatness detection before pre-alignment allows the wafer placed on the rotating platform to have a certain flatness, so that it can be adsorbed by the rotating platform and will not fall off or shift during the rotation process, causing deviations in the pre-alignment results.

[0073] The flatness detection of the wafer is performed by the maximum difference of the pressure values ​​collected by the pressure sensor, specifically including:

[0074] Find the maximum and minimum pressure values ​​at the same time;

[0075] Calculate the difference between the maximum and minimum values ​​to get the maximum difference;

[0076] Determine whether the maximum difference is less than the set threshold;

[0077] If so, the wafer flatness test is qualified; if not, the wafer is judged to be abnormal and an abnormal alarm signal is issued.

[0078] In one embodiment, the wafer 5 should be flat in an ideal state, so the pressure on the support surface 211 when carrying the wafer 5 should be the same. However, if the wafer 5 is warped, the lower surface of the wafer 5 may not be against the support surface 211. At this time, the pressure on the support surface 211 is different, and the pressure sensors 7 at different positions will collect pressure values ​​of different sizes, but some warping is within an acceptable range. Therefore, at the same time, when the difference between the maximum and minimum values ​​in the pressure value exceeds or equals the threshold, the wafer 5 is determined to be abnormal and an abnormal alarm signal is issued.

[0079] In one embodiment, see the attached Figure 3 As shown, a pressure sensor 7 is respectively arranged on the supporting surfaces 211 of the two supporting members 21. When the pressure values ​​of the two pressure sensors 7 are equal, the lower surface of the wafer 5 is flat. When the difference between the pressure values ​​of the two pressure sensors 7 is greater than the threshold value, it means that the difference between the pressures received by the two supporting surfaces is too large, and at this time, the lower surface of the wafer 5 is not flat and abnormal.

[0080] The more pressure sensors 7 are installed, the more points are collected, and the abnormality detection of the wafer 5 is more accurate, but the cost will also increase.

[0081] In one embodiment, at least two pressure sensors 7 are evenly spaced along the second direction on the support surface 211, and the pressure sensors 7 located in the same row in the second direction serve as a detection portion, and at least two detection portions are evenly distributed along the first direction on the support surface 211. The pressure sensors 7 in one detection portion can detect the warpage of the wafer in the second direction, and the pressure sensors in different detection portions can detect the warpage of the wafer in the first direction.

[0082] For example, see the attached Figure 4 As shown, two detection parts are arranged on the support surface, and each detection part includes three pressure sensors. The three pressure sensors of one detection part on one support surface are pressure sensor A7a, pressure sensor B7b and pressure sensor C7c, the three pressure sensors of another detection part are pressure sensor D7d, pressure sensor E7e and pressure sensor F7f, and the corresponding six pressure sensors on another support surface are pressure sensor G7g, pressure sensor H7h, pressure sensor I7i, pressure sensor J7j, pressure sensor K7k and pressure sensor L7l.

[0083] When the wafer 5 is flat, after the support surface 211 carries the wafer, the pressure values ​​of the twelve pressure sensors 7 should be the same. If the wafer is warped in the second direction, and the middle of the wafer 5 is warped upward, the pressure values ​​of the twelve pressure sensors are different, and there may be a pressure value of pressure sensor A>pressure value of pressure sensor B>pressure value of pressure sensor C and pressure value of pressure sensor I>pressure value of pressure sensor H>pressure value of pressure sensor G. If the wafer 5 is warped in the first direction, the pressure values ​​of the twelve pressure sensors 7 are different, and the pressure value of pressure sensor A is not equal to the pressure value of pressure sensor D. When there is local warping in the area where the wafer 5 abuts against a support surface 211, the pressure values ​​detected by the pressure sensors 7 on this support surface 211 will also be different.

[0084] Therefore, by comparing these pressure values, wafer inspection can be quickly performed, the maximum and minimum pressure values ​​at the same time are found, and the difference between the maximum and minimum values ​​is compared with the set threshold. When the difference is greater than or equal to the threshold, it means that the wafer is not flat and the warpage exceeds the acceptable range. The threshold is set manually and can be set according to the actual tolerance range.

[0085] In this embodiment, by adding a pressure sensor 7 and judging the pressure value of the pressure sensor, the wafer 5 can be inspected through the transfer mechanism 2. The transfer mechanism 2 needs to carry the wafer before and after the wafer 5 is aligned, so the wafer inspection is performed before and after the wafer 5 is aligned. After the wafer 5 is rotated on the rotating platform, different positions of the wafer 5 abut against the supporting surface 211, and the flatness inspection can be performed on different areas of the wafer 5, thereby improving the comprehensiveness of the inspection.

[0086] In one embodiment, the minimum distance between the two support members 21 in the X direction is not less than the width of the fork 1. The width of the fork 1 refers to the maximum length of the fork 1 in the X direction, that is, the maximum distance between the two fingers in the X direction. At this time, the distance between the two support members forms a gap for the fork 1. The two fingers are located between the two support members. When the wafer 5 on the fork 1 is placed on the support member 21, the fork 1 can be withdrawn from between the two support members 21. This structure is discussed in this embodiment. Of course, the maximum distance between the two support members 21 in the X direction can also be less than the minimum distance between the two fingers of the fork 1. At this time, the two fingers are respectively located on the side of the two support members away from each other, and the two support members are located between the two fingers. At this time, there will be no interference between the fork and the support member.

[0087] In one embodiment, two support members 21 are symmetrically disposed on both sides of the rotating platform 31 in the X direction.

[0088] In another embodiment, the two support members 21 may not be symmetrically arranged relative to the rotating platform. In this case, the minimum spacing between the two support members 21 and the rotating platform in the X direction is different. In this case, the support members 21 can also carry the wafers transported by the wafer fork, as long as the rotating platform 31 is located between the two support members 21. However, in this case, the support members 21 are also asymmetrical relative to the central axis of the wafer, which may cause the wafer to tilt, so the offset of the support members 21 cannot be too large.

[0089] See attached Figure 3 and attached Figure 4 As shown, in this embodiment, the fork 1 carries a wafer 5 and moves in the horizontal direction until the wafer 5 is coaxial with the rotating platform 31. At this time, the support surface 211 is located above the rotating surface 311 but below the wafer 5, and the fork 1 is located directly above the spacing between the two support members 21. The fork 1 drives the wafer 5 to move downward until the position of the bearing surface of the fork 1 is lower than the position of the support surface 211. At this time, the wafer 5 is already supported on the support member 21. Then the fork 1 moves horizontally between the two support members 21 in the horizontal direction away from the rotating platform 31. The support member 21 moves downward synchronously under the drive of the linear module 22 until the support surface 211 is lower than the height of the rotating surface 311. At this time, the wafer 5 is already supported and fixed on the rotating surface 311. The rotating platform 31 drives the wafer 5 to rotate and align the wafer 5. In this process, the two support members 21 only lift the wafer 5, which will not cause damage to the wafer 5. At the same time, the flatness of the wafer can be detected through the pressure sensor thereon.

[0090] In one embodiment, the support member 21 includes a support member body and a plurality of friction blocks 24 extending upward along the support member body, the upper end surface of the friction block 24 is the support surface 211, the friction block 24 is arranged corresponding to the pressure sensor 7, the pressure sensor is fixed on the corresponding friction block, and the pressure sensor 7 detects the pressure value on the corresponding friction block.

[0091] The friction block 24 increases the friction force with the wafer 5, prevents the wafer 5 from slipping, and improves the stability of the transfer mechanism 2 when lifting the wafer 5. The upper end surface of the friction block 24 can also be flush with the upper end surface of the support body. The friction block 24 is embedded in the support body. At this time, the friction block 24 and the upper end surface of the support body together form a support surface 211.

[0092] In one embodiment, see the attached Figure 4 As shown, the support member 21 may also only include a support member body without the friction block 24. In this case, the upper surface of the support member body is the support surface 211. The connecting member 23 is fixedly connected to the support member body. In this case, the pressure sensor is directly arranged on the support member body.

[0093] See attached Figure 3 As shown, two support members 21 are connected to the same linear module 22 through a connecting member 23. The connecting member 23 connects the two support members 21 into a whole. At this time, one linear module 22 can drive the two support members 21 to rise and fall synchronously. The connecting member 23 is a U-shaped structure and extends in the horizontal direction. The connecting member 23 includes two parallel connecting parts 231 and a fixed part 232 located between the two connecting parts 231. The fixed part 232 is connected to the linear module 22, and the support member 21 is arranged on the side of the connecting part 231 away from the fixed part 232. Because the slice fork 1 will move downward relative to the support member 21, the height position of the upper end face of the fixed part 232 is lower than the height position of the support surface 211. The height difference between the upper end face of the fixed part 232 and the support surface 211 is not less than the thickness of the slice fork 1 in the Z direction, which provides sufficient moving space for the slice fork 1 to move downward relative to the support member 21.

[0094] In one embodiment, the transfer mechanism further includes a translation drive, the output end of which is connected to the linear module, and the translation drive drives the linear module to move along the first direction to adjust the position of the support member in the first direction, so that a vertical plane in the second direction can pass through the support surface and the rotating platform at the same time, that is, the projections of the support surface and the rotating platform in the second direction partially overlap. Of course, the translation drive may not be provided, in which case the position of the support surface needs to ensure that a vertical plane in the second direction can pass through the support surface and the rotating platform at the same time, and the projections of the support surface and the rotating platform in the second direction partially overlap.

[0095] In one embodiment, see the attached Figure 2 and attached Figure 3As shown, the minimum distance between the two connecting parts 231 is the same as the minimum distance between the two supporting members 21, and the height position of the upper end surface of the connecting part 231 is the same as the height position of the upper end surface of the fixing part 232. At this time, the connecting member 23 is an upper protrusion extending upward along the connecting part 231.

[0096] Of course, the height position of the upper end surface of the connection part 231 can also be the same as the height position of the support surface 211, and the minimum spacing between the two connection parts 231 is greater than the minimum spacing between the two support members 21. When the minimum spacing between the two connection parts 231 is greater than or equal to the minimum spacing between the support members 21, the connection part 231 will not be located directly below the slice fork 1, and will not interfere with the downward movement of the slice fork 1. As long as the upper end surface of the connection part 231 is not higher than the height position of the support surface 211, it will not interfere with the placement of the wafer 5 on the support surface 211. At this time, only one concave surface is provided on the fixing part 232 to make way for the downward movement of the slice fork 1, which can meet the requirements.

[0097] In one embodiment, the minimum spacing between the two connecting portions 231 is smaller than the width of the slice fork 1. At this time, a portion of the connecting portion 231 will be located directly below the slice fork 1. Therefore, the height of the upper end surface of the connecting portion 231 must be lower than or equal to the height position of the upper end surface of the fixing portion 232 to provide space for the downward movement of the slice fork 1.

[0098] When the two support members 21 are connected into a whole through a connecting member 23, the upper end surface of the fixing portion 232 will inevitably be lower than the height position of the support surface 211, but the height position of the upper end surface of the connecting portion 231 can be set according to actual needs, which is related to the position relationship of the connecting portion 231 relative to the fork 1, but the upper end surface of the connecting portion 231 will inevitably not be higher than the height position of the support surface 211.

[0099] In one embodiment, the connecting member 23 and the supporting member 21 may be an integral structure or a separate structure.

[0100] In one embodiment, an auxiliary part is fixed to one end of the support member 21 away from the connecting member 23. The auxiliary part is located between the two support members 21 and on one side of the rotating platform 31. At this time, the support member 21, the auxiliary part and the connecting member 23 form a U-shape. The auxiliary part has an auxiliary surface, which is located at the same height as the supporting surface 211. The auxiliary surface can also support the lower surface of the wafer 5. Providing an auxiliary part can increase the contact area between the transfer mechanism 2 and the wafer 5. However, due to the addition of the auxiliary surface, the auxiliary surface and the supporting surface 211 are not stacked relative to the rotating platform 31, that is, they are not symmetrical relative to the center of the wafer 5, which may cause the wafer 5 to tilt and shift on the transfer mechanism 2.

[0101] In one embodiment, see the attached Figure 4As shown, the linear module 22 is arranged corresponding to the support member 21, and two linear modules 22 are arranged. One linear module 22 drives the corresponding support member 21 to rise and fall. At this time, the two support members 21 do not need to be connected into a whole by the connecting member 23, but can be connected to the corresponding linear module 22. Figure 5 The hollow arrow direction moves toward the rotating platform, from between the two support members 21 to just above the rotating platform.

[0102] The switching mechanism 2 further includes a limiting column 25, which is used to limit the rising distance of the support member 21. The limiting column 25 can be a damping buffer limiter.

[0103] See attached Figure 3 As shown, the linear module 22 is a cylinder, the piston rod of the cylinder is extended and retracted in the vertical direction, and the cylinder is connected to the connecting member 23. A connecting block 26 is fixed on the piston rod, and the connecting block 26 is fixedly connected to the connecting member 23. The limiting column 25 is located above the fixed block. When the limiting column 25 abuts against the fixed block, the fixed block is limited to rise, that is, the upward movement distance of the support member 21 is limited. When the piston of the cylinder moves down to the limit distance, the support member 21 also reaches the maximum downward movement distance.

[0104] In one implementation, the linear module 22 is fixed on a stand 27, and the limit column 25 can be fixed on the stand 27. The stand 27 is provided with a guide rail for the connection block 26 to slide, providing guidance for the lifting and lowering of the connection block 26 (connecting member 23 and supporting member 21).

[0105] See attached Figure 2 As shown, the pre-alignment mechanism 3 also includes a detection component, which is located on one side of the rotating platform 31. The detection component includes a detection slot 32 and a detection element (not shown in the figure). The detection element is fixed in the detection slot 32 and can emit vertical detection light. The height of the detection slot 32 is greater than the thickness of the wafer 5. When the wafer 5 is placed on the rotating platform 31 and rotates synchronously with the rotating platform 31, the edge of the wafer 5 can be inserted into the detection slot 32 and the detection element detects the gap at the edge of the wafer 5. When the wafer 5 does not block the detection light during the rotation process, it means that the wafer 5 has been aligned, and the rotating platform 31 stops rotating.

[0106] The detection element is a through-beam sensor, including a transmitting end and a receiving end arranged up and down. The detection element detects the notch of the wafer 5 to achieve alignment, which is a prior art and will not be described in detail here.

[0107] See attached Figure 5As shown, the two support members 21 are symmetrically arranged relative to a vertical plane 6, the central axis of the rotating platform 31 passes through this vertical plane 6, and the detection slot 32 is also arranged on this vertical plane 6, that is, the detection slot 32 and the two support members 21 form an isosceles triangle. Such an arrangement facilitates the movement of the wafer fork 1 and the transportation of the wafer 5. At this time, the wafer fork 1 can directly approach or move away from the detection slot 32 along a straight line between the two support members 21. At this time, the linear module 22 is located on the side of the rotating platform 31 away from the pre-alignment mechanism 3, and the detection component and the transfer mechanism 2 are arranged at intervals along the Y direction.

[0108] Of course, in some embodiments, the detection assembly and the transfer mechanism 2 may not be arranged at intervals in the Y direction, but a certain angle may be provided between the two. In this case, the wafer 5 on the fork 1 can be transferred. The position of the transfer mechanism 2 is set according to the route of the fork 1. As long as the two support members 21 are symmetrically arranged on both sides of the rotating platform 31, and the distance between the two needs to allow the fork 1 to pass through.

[0109] The pre-alignment mechanism also includes a fixed plate, which is L-shaped and includes a vertical plate and a horizontal plate. The rotating platform 31 is rotatably connected to the horizontal plate, and the detection slot 32 is opened on the vertical plate.

[0110] See attached Figure 1 and attached Figure 2 As shown, the wafer alignment device further includes a substrate 4 , and the fixing plate of the pre-alignment mechanism 3 and the stand 27 of the transfer mechanism 2 are both fixed on the substrate 4 .

[0111] The above implementation modes are only for illustrating the technical concept and features of the present invention, and their purpose is to enable people familiar with this technology to understand the content of the present invention and implement it, and they cannot be used to limit the protection scope of the present invention. Any equivalent changes or modifications made according to the spirit of the present invention should be included in the protection scope of the present invention.

Claims

1. A wafer alignment method, characterized in that: The wafer transported by the wafer fork is aligned based on the wafer alignment device, and the wafer alignment device comprises: A pre-alignment mechanism, the pre-alignment mechanism comprising a rotating platform, the fork approaches or moves away from the rotating platform along a first direction in a horizontal plane, and a detection slot for inserting the wafer edge is provided on one side of the rotating platform; A transfer mechanism, wherein the transfer mechanism comprises two support members located on both sides of the rotating platform, the two support members are arranged at intervals in a horizontal plane along a second direction perpendicular to the first direction, each of the support members comprises a support surface located at the same height position and capable of carrying the wafer, each of the support surfaces is provided with at least one pressure sensor for obtaining a pressure value on the support surface, and the two support members can move up and down synchronously; the wafer alignment method comprises: The support member moves upward until the height of the support surface is higher than the height of the rotating surface of the rotating platform, and the height difference between the support surface and the rotating surface is greater than the thickness of the fork; The wafer is clamped by the fork and the height position of the wafer is adjusted until the lower surface of the wafer is located above the support surface and the lower groove surface of the detection groove, and the upper surface of the wafer is located below the upper groove surface of the detection groove; The wafer is driven by the fork to move along the first direction toward the inspection slot until the central axis of the wafer coincides with the central axis of the rotating platform; The fork drives the wafer to move downward until the lower surface of the wafer abuts against the supporting surface, and the fork releases the clamping of the wafer; Performing wafer flatness detection by using the maximum difference of the pressure values ​​collected by the pressure sensor; When the flatness test of the wafer is qualified, the fork continues to move downward until it moves to a height position where the upper end surface of the fork is lower than the support surface, and the fork moves out in a horizontal plane in a direction away from the detection slot; The support member moves downward until it moves to a height position where the support surface is lower than the rotating surface, the wafer is carried on the rotating surface, and the rotating surface absorbs the wafer; The rotating platform drives the wafer to rotate synchronously, and the detection groove pre-aligns the wafer; After pre-alignment, the rotating surface stops adsorbing the wafer, the supporting member moves upward until it moves to a height position where the supporting surface is higher than the rotating surface, and the wafer is supported on the supporting surface; Performing wafer flatness detection by using the maximum difference of the pressure values ​​collected by the pressure sensor; When the flatness detection of the wafer is qualified, the fork carries the wafer on the supporting surface away from the wafer alignment device.

2. The wafer alignment method according to claim 1, characterized in that: The flatness detection of the wafer by using the maximum difference of the pressure values ​​collected by the pressure sensor specifically includes: Find the maximum and minimum values ​​of the pressure values ​​at the same time; Calculating the difference between the maximum value and the minimum value to obtain the maximum difference; Determine whether the maximum difference is less than a set threshold; If so, the flatness test of the wafer is qualified; if not, the wafer is determined to be abnormal and an abnormal alarm signal is issued.

3. The wafer alignment method according to claim 1, characterized in that: At least two pressure sensors are evenly spaced apart on the support surface along the second direction to form a detection portion, and at least two detection portions are arranged on the support surface along the first direction.

4. The wafer alignment method according to claim 1, characterized in that: The support member comprises a support member body, on which friction blocks corresponding to the pressure sensors are arranged one by one, the upper end surface of the friction blocks is the support surface, and the upper end surface of the friction blocks is not lower than the upper end surface of the support member body.

5. The wafer alignment method according to claim 1, characterized in that: The transfer mechanism further includes a linear module, which is connected to the two support members via a connecting member, and is used to drive the support members to move up and down, wherein the connecting member includes two connecting parts and a fixing part located between the two connecting parts, and the support member is arranged on a side of the connecting part away from the fixing part; The height position of the upper end surface of the fixing portion is lower than the height position of the supporting surface, and the height difference between the upper end surface of the fixing portion and the supporting surface is not less than the thickness of the slice fork.

6. The wafer alignment method according to claim 5, characterized in that: The minimum distance between the two connecting parts in the second direction is not less than the width of the fork, and the upper end surface of the connecting part is not higher than the height position of the supporting surface; Or the minimum spacing between the two connecting parts in the second direction is smaller than the width of the slice fork, the upper end surface of the connecting part is lower than the height position of the supporting surface, and the height difference between an upper end surface located at a higher position between the upper end surface of the connecting part and the upper end surface of the fixing part and the supporting surface is not less than the thickness of the slice fork.

7. The wafer alignment method according to claim 1, characterized in that: The detection slot is arranged on a vertical plane passing through the central axis of the detection platform, and two support members are symmetrically arranged on both sides of the vertical plane.

8. The wafer alignment method according to claim 1, characterized in that: The transfer mechanism further comprises a limiting column, and the limiting column is used to limit the rising distance of the support member.

9. The wafer alignment method according to claim 1, characterized in that: A detection element is arranged in the detection groove, and the detection element can emit vertical detection light. The edge of the wafer adsorbed on the rotating platform can be inserted into the detection groove and detected by the detection element.

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