Wafer transfer apparatus and wafer pickup method

Abstract

This invention provides a wafer transfer device and a wafer picking method. The wafer transfer device includes a translation mechanism and a robotic arm. The robotic arm picks up wafers via symmetrically distributed first and second branch components at its ends. The first and second branch components are connected to one end of a connecting member on the robotic arm along its length. The end of the connecting member away from the first and second branch components is connected to the translation mechanism via a support frame. The connecting member is equipped with a gravity sensor, which is electrically connected to both the first and second branch components. This invention addresses the problem in existing technologies where low wafer picking accuracy leads to positional misalignment, potentially increasing the misalignment or even causing wafer drop during subsequent wafer transfer.

Description

Technical Field

[0001] This invention relates to the field of wafer fabrication equipment, and more particularly to a wafer transfer device and a wafer pickup method. Background Technology

[0002] In the semiconductor device manufacturing process, robotic arms are needed to precisely transfer wafers between various process stations. It is necessary to reduce the positional deviations caused by the transfer of wafers between different stations in order to stabilize the consistency of process parameters in each process and thus ensure the yield of the final product.

[0003] Current robotic arms typically rely solely on the torque of the motor in the transmission component to sense and determine if the wafer is misaligned when gripping it. This method of determining wafer gripping accuracy is relatively inaccurate, and the gripping position may have greater errors for wafers of different sizes. When the wafer gripping position deviates, it can lead to more severe positional shifts during subsequent movement of the wafer by the robotic arm, potentially even causing the wafer to fall off and be damaged. Therefore, it is necessary to improve existing wafer transfer equipment and wafer alignment methods to address these problems.

[0004] It should be noted that the above description of the background technology is only for the purpose of providing a clear and complete explanation of the technical solutions of this application and facilitating understanding by those skilled in the art. It should not be assumed that these technical solutions are known to those skilled in the art simply because they have been described in the background technology section of this application. Summary of the Invention

[0005] The purpose of this invention is to disclose a wafer transfer device and a wafer picking method, wherein the wafer transfer device is used to solve the problem in the prior art that the wafer picking accuracy is low and there is positional offset, which may further increase the offset or even cause wafer drop in the subsequent wafer transfer process.

[0006] To achieve the above objectives, the present invention provides a wafer transfer device, comprising: a translation mechanism and a robotic arm, wherein the robotic arm picks up wafers by means of a first branch member and a second branch member symmetrically distributed at its end, the first branch member and the second branch member being connected to one end of a connecting member of the robotic arm along its length, and the end of the connecting member away from the first branch member and the second branch member being connected to the translation mechanism via a support frame. The connecting member is equipped with a gravity sensor, which is electrically connected to the first branch member and the second branch member respectively.

[0007] As a further improvement of the present invention, the robotic arm has a first robotic arm and a second robotic arm arranged coaxially, and the support frame includes a first support frame and a second support frame, the top ends of the first support frame and the second support frame being respectively connected to the connecting members of the first robotic arm and the second robotic arm.

[0008] As a further improvement of the present invention, the first support frame includes a first connecting plate, a second connecting plate and a third connecting plate. One end of the first connecting plate in the length direction is connected to the driving end of the translation mechanism. The other end of the first connecting plate extends in a direction away from the translation mechanism and is vertically fixed to the second connecting plate. The top end of the second connecting plate is vertically upward and connected to one end of the third connecting plate in the length direction. The end of the third connecting plate away from the second connecting plate is connected to the first robotic arm. The second support frame includes a connecting seat and a support rod. One end of the connecting seat is connected to the other drive end of the translation mechanism. The support rod is vertically fixed to the upper surface of the connecting seat, and the second robotic arm is mounted on the top of the support rod.

[0009] As a further improvement of the present invention, the lower surface of the first branch member is provided with a first suction cup and a second suction cup along the length direction, and the lower surface of the second branch member is provided with a third suction cup and a fourth suction cup along the length direction. The first suction cup, the second suction cup, the third suction cup and the fourth suction cup are simultaneously attached to the upper surface of the wafer. The first branch component and the second branch component are integrally formed to form an air passage that communicates with the first suction cup, the second suction cup, the third suction cup and the fourth suction cup.

[0010] As a further improvement of the present invention, the connecting member includes a connecting rod body, a first connecting portion and a second connecting portion, wherein the first connecting portion and the second connecting portion are formed at both ends of the connecting rod body; The first connecting part is attached and fixed to the connection between the first branch member and the second branch member, and the end of the first connecting part away from the main body of the connecting rod forms an air inlet that communicates with the air passage.

[0011] As a further improvement of the present invention, the gravity sensor is mounted on the upper surface of the connecting rod body and is optionally a thin-film gravity sensor; The air passage is formed on the upper surface of the first branch member and the second branch member and sealed by a cover of the same shape. The first branch member and the second branch member are electrically connected to the gravity sensor through the cover.

[0012] As a further improvement of the present invention, the ends of the first branch member and the second branch member away from the connecting member are respectively formed into arc shapes, and the connection between the first branch member and the second branch member is a circular arc transition.

[0013] As a further improvement of the present invention, a rotating device is fixedly connected to the top of the third connecting plate and the top of the support rod, and the second connecting parts of the two connecting members are respectively connected to the driving ends of the two rotating members.

[0014] The present invention also discloses a wafer pick-up method, implemented based on any one of the wafer transfer devices described above, comprising the following steps: S1, the translation mechanism drives the robotic arm to move toward the wafer to be picked up; S2, when the robotic arm moves to a position where the first branch component and the second branch component are symmetrically located on both sides of the diameter direction of the wafer to be picked up, the translation mechanism is stopped; S3, picking up the wafer through the first branch component and the second branch component; S4, determine whether the difference in gravity from the wafer between the first branch component and the second branch component is greater than a threshold value using the gravity sensor; S5, if not, drive the robotic arm to reverse the displacement of the wafer to be picked up through the translation mechanism; S6, if yes, return to step S2.

[0015] As a further improvement of the present invention, it also includes: the threshold is set based on the wafer size.

[0016] Compared with the prior art, the beneficial effects of the present invention are as follows: Through the first and second branch components symmetrically formed at the end of the robotic arm, and the gravity sensor electrically connected to the first and second branch components, when the first and second branch components synchronously pick up the wafer, if the picking accuracy is sufficient, the gravity force received by the first and second branch components as obtained by the gravity sensor is completely equal or has a very small difference, indicating that there is no wafer misalignment. The robotic arm can then be driven by a translation mechanism to move the wafer it carries to the next process. If there is an error in the picking accuracy, the uneven force on the first and second branch components causes a certain offset, and the gravity difference received by the gravity sensor will exceed the threshold set based on the wafer size. This indicates that moving the wafer at this time may lead to increased errors in subsequent wafer transfer processes. Therefore, in this state, the first and second branch components are controlled to pick up the wafer again until the accuracy meets the requirements, thereby effectively solving the problem in the prior art where low wafer picking accuracy leads to positional offset, which may further increase the offset or even cause wafer drop during subsequent wafer transfer processes. Attached Figure Description

[0017] Figure 1 This is a schematic diagram illustrating the specific structure of the semi-automatic alignment device in this invention; Figure 2 is a schematic diagram showing the specific structure of the mechanical arm in the present invention; Figure 3 is Figure 1 an enlarged view of part A in Figure 4 is Figure 1 an enlarged view of part B in Figure 5 is a sectional view showing the inner wall structure of the mechanical arm in the present invention; Figure 6 is Figure 5 an enlarged view of part C in Figure 7 is Figure 5 an enlarged view of part D in Figure 8 is a schematic diagram showing the specific structures of the lower surfaces of the first branch member and the second branch member in the present invention; Figure 9 is a schematic diagram of the steps of the wafer picking method in the present invention. DETAILED DESCRIPTION

[0018] The present invention will be described in detail below with reference to the various embodiments shown in the accompanying drawings, but it should be noted that these embodiments do not limit the present invention, and any equivalent changes or substitutions in functions, methods or structures made by those of ordinary skill in the art based on these embodiments shall fall within the protection scope of the present invention.

[0019] Reference Figures 1 to 8As shown, it is a wafer transfer device disclosed in the present invention. Compared with the prior art, in this embodiment, through the first branch member 1 and the second branch member 2 symmetrically formed at the end of the mechanical arm 10, and the gravity sensor 31 electrically connected to the first branch member 1 and the second branch member 2, when the first branch member 1 and the second branch member 2 pick up the wafer 6 synchronously, if the picking accuracy is sufficient, the gravity received by the first branch member 1 and the second branch member 2 acquired by the gravity sensor 31 is completely equal or the difference is extremely small, it can be determined that there is no misalignment in the picking of the wafer 6 at this time, and the translation mechanism 4 can drive the mechanical arm 10 as a whole to drive the wafer 6 carried by it to translate to the next process; if there is an error in the picking accuracy, due to the uneven force on the first branch member 1 and the second branch member 2, the first branch member 1 and the second branch member 2 will have a certain offset, and the gravity difference between the first branch member 1 and the second branch member 2 acquired by the gravity sensor 31 will exceed the threshold set based on the wafer size, which indicates that moving the wafer 6 at this time may increase the error in the subsequent wafer transferring process. Therefore, in this state, the first branch member 1 and the second branch member 2 are controlled to re-pick the wafer 6 until the accuracy meets the requirements, thereby effectively solving the problem in the prior art that the low wafer grabbing accuracy causes position offset, which may further increase the offset or even cause wafer dropping in the subsequent wafer transfer process.

[0020] Referring to Figures 1 to 8 As shown, in this embodiment, the wafer transfer device includes: a translation mechanism 4 and a mechanical arm 10. The mechanical arm 10 picks up the wafer 6 through the first branch member 1 and the second branch member 2 symmetrically arranged at the end. The first branch member 1 and the second branch member 2 are connected to one end of the connecting member 3 of the mechanical arm 10 in the length direction, and the end of the connecting member 3 away from the first branch member 1 and the second branch member 2 is connected to the translation mechanism 4 through a support frame 5; the connecting member 3 is provided with a gravity sensor 31, and the gravity sensor 31 is electrically connected to the first branch member 1 and the second branch member 2 respectively.

[0021] Referring to Figures 2 to 8 As shown, the lower surface of the first branch member 1 is provided with a first suction cup 11 and a second suction cup 12 along the length direction, the lower surface of the second branch member 2 is provided with a third suction cup 21 and a fourth suction cup 22 along the length direction, and the first suction cup 11, the second suction cup 12, the third suction cup 21 and the fourth suction cup 22 fit the upper surface of the wafer 6 synchronously; the first branch member 1 and the second branch member 2 are integrally formed and form an air path 13 communicated with the first suction cup 11, the second suction cup 12, the third suction cup 21 and the fourth suction cup 22.

[0022] Referring to Figures 2 to 8As shown, the connecting member 3 includes a connecting rod body 32, a first connecting portion 33, and a second connecting portion 34. The first connecting portion 33 and the second connecting portion 34 are formed at both ends of the connecting rod body 32. The first connecting portion 33 is fitted and fixed to the connection between the first branch member 1 and the second branch member 2. An air inlet 35 communicating with the air passage 13 is formed at the end of the first connecting portion 33 away from the connecting rod body 31. The first connecting portion 33 has an air passage 351 communicating with the air inlet 35 and the air passage 13. The air passage 35 is formed on the upper surface of the first branch member 1 and the second branch member 2 and sealed by a cover 23 of the same shape. The first branch member 1 and the second branch member 2 are electrically connected to the gravity sensor 31 through the cover 23. The gravity sensor 31 is assembled on the upper surface of the connecting rod body 32 and is optionally a thin-film gravity sensor. The ends of the first branch member 1 and the second branch member 2 away from the connecting member 3 are respectively formed into arc shapes, and the connection between the first branch member 1 and the second branch member 2 is a rounded transition.

[0023] Specifically, the wafer transfer device described in this embodiment is applicable to wafer flat plating equipment, single-wafer cleaning equipment, or other single-wafer wafer processing equipment. In the aforementioned single-wafer wafer processing equipment, the wafer is placed flat and supported inside the equipment (not shown) by an electroplating cup or worktable. Therefore, it is necessary to pick up the wafer by using suction cups to generate negative pressure and suck up the upper surface of the wafer. When using the wafer transfer device in this embodiment for wafer transfer, the translation mechanism 4 controls the robotic arm 10 to move directly above the wafer 6. Then, through the air inlet 35 and the air passage 13 formed on the first branch member 1 and the second branch frame 2, the first suction cup 11, the second suction cup 12, the third suction cup 21, and the fourth suction cup 22 simultaneously generate negative pressure and... Figure 1 The wafer 6 is picked up in the posture shown, so as to apply force to multiple points on the surface of the wafer 6 and maintain the effect of picking up the wafer 6 stably.

[0024] Furthermore, when the first suction cup 11, the second suction cup 12, the third suction cup 21, and the fourth suction cup 22 simultaneously pick up the wafer 6, the gravity sensor 31 determines whether the gravity on the first branch component 1 and the second branch component 2 is consistent, or whether the difference in gravity on the first branch component 1 and the second branch component 2 is less than a threshold. When the pressure values ​​on the first branch component 1 and the second branch component 2 are consistent or less than the threshold, it indicates that the first branch component 1 and the second branch component 2 are symmetrically located on both sides of the diameter of the wafer 6 in this state. The first suction cup 11, the second suction cup 12, the third suction cup 21, and the fourth suction cup 22 form a square around the center line of the wafer 6, which can apply a stable lifting force to the wafer 6. At this time, the translation mechanism 4 can be controlled to drive the robotic arm 10 to the next process equipment.

[0025] In this embodiment, the air path 13 formed in a Y shape on the upper surfaces of the first branch member 1 and the second branch member 2 realizes the purpose that the air path 13 can simultaneously communicate with the first suction cup 11, the second suction cup 12, the third suction cup 21, and the fourth suction cup 22. Further, in this embodiment, the covering member 23 covering the air path 13 is optionally Y-shaped consistent with the shape of the air path 13, and a stepped groove (not marked) for embedding the covering member 23 is formed at the opening edge of the air path 13 to achieve the purpose of sealing the air path 13. In addition, since the covering member 23 is configured as a metal member and is electrically connected to the gravity sensor 31, its symmetrical structure can achieve the effect of sealing the air path 13, and at the same time, can accurately measure the gravity from the wafer respectively received by the first branch member 1 and the second branch member 2.

[0026] It should be noted that when the wafer transfer device in this embodiment is applied to a wafer level plating apparatus, the first branch member 1, the second branch member 2, and the gravity sensor 31 formed on the connecting rod main body 32 not only have the function of judging whether the picking position for picking the wafer 6 is accurate, but also can judge whether the electroplated layer of the wafer is uniform. Specifically, if the wafer picking position is accurate but the gravity difference between the first branch member 1 and the second branch member 2 exceeds the set threshold, it indicates that there is a problem of uneven electroplating on the surface electroplated layer of the wafer, so the wafer transfer device in this embodiment further has the function of judging the wafer electroplating effect. When the gravity received by the first branch member 1 and the second branch member 2 is consistent or the gravity difference is less than the threshold, it indicates that there is no offset or the offset is very small for the first branch member 1 and the second branch member 2. In this state, the picking accuracy of the wafer 6 meets the requirements, and the electroplated layer formed on the surface of the wafer 6 is uniform, which is suitable for the next process.

[0027] Refer Figure 1 as shown, the mechanical arm 10 has a first mechanical arm 101 and a second mechanical arm 102 arranged coaxially, the support frame 5 includes a first support frame 51 and a second support frame 52, the top ends of the first support frame 51 and the second support frame are respectively connected to the connecting members 3 respectively provided on the first mechanical arm 101 and the second mechanical arm 102. The first support frame 51 includes a first connection plate 511, a second connection plate 512, and a third connection plate 513, one end of the first connection plate 511 in the length direction is connected to the driving end of the translation mechanism 4, the other end of the first connection plate 511 extends toward a direction away from the translation mechanism 4 and is vertically fixed with the second connection plate 512, the top end of the second connection plate 512 is vertically upward and connected to one end of the third connection plate 513 in the length direction, and the end of the third connection plate away from the second connection plate 512 is connected to the first mechanical arm 101; the second support frame 52 includes a connection seat 521 and a support rod 522, one end of the connection seat 521 is connected to the other driving end of the translation mechanism 4, the support rod 522 is vertically fixed on the upper surface of the connection seat 521, and the second mechanical arm 102 is mounted on the top end of the support rod 522.

[0028] Specifically, in this embodiment, the translation mechanism 4 is optionally a double-mover linear motor, and its two driving ends (not shown) are respectively connected to the first support frame 51 and the second support frame 52, so as to achieve the effect of simultaneously transferring two wafers, or selecting the first robot arm 101 or the second robot arm 102 for wafer transfer according to the height of the equipment, thereby having higher adaptability and being suitable for wafer transfer requirements in various wafer manufacturing processes. In this embodiment, through the structural design of the first support frame 51 and the second support frame 52, while the first robot arm 101 and the second robot arm 102 can be driven by the translation mechanism 4 at the same time, the first branch member 1 and the second branch member 2 respectively included in the first robot arm 101 and the second robot arm 102 can be arranged up and down in a concentric posture, and can provide stable supporting force for the first robot arm 101, the second robot arm 102 and the wafers 6 picked by them respectively.

[0029] Reference Figure 1 As shown in the figure, a rotating device 36 is fixedly connected to the top ends of the third connecting plate 513 and the supporting rod 522 respectively, and the second connecting portions 34 of the two connecting members 3 are respectively connected to the driving ends of the two rotating members 3. It should be noted that in this embodiment, the rotating device 36 can optionally be a driving motor, or any other device that can realize the rotation function. Further, in combination with the foregoing description, the wafer transfer equipment in this embodiment is adapted to wafers in a horizontal state, and in the entire process flow of wafers, it may be necessary to feed wafers into the equipment at different inclination angles (for example, perpendicular to the horizontal plane). In this embodiment, the rotating device 36 is provided to change the inclination angles of the first robot arm 101 and the second robot arm 102, so that the wafers 6 picked by the corresponding first branch member 1 and second branch member 2 can be fed into different equipment in different inclination postures.

[0030] Reference Figure 9 As shown in the figure, the present invention also discloses a wafer picking method, which is implemented based on the wafer transfer equipment in the foregoing embodiment, and includes the following steps: S1, driving the robot arm to displace towards the wafer to be picked by the translation mechanism.

[0031] S2, shutting down the translation mechanism when the robot arm moves to the position where the first branch member and the second branch member are symmetrically located on both sides of the diameter direction of the wafer to be picked.

[0032] S3, picking the wafer through the first branch member and the second branch member.

[0033] S4, the gravity sensor determines whether the difference in gravity between the first branch component and the second branch component from the wafer exceeds a threshold. It should be noted that the threshold is set based on the wafer size. For example, when this embodiment is applied to wafer picking in a wafer plating equipment, the entire plated wafer weighs approximately 54 grams for an 8-inch wafer and 120 grams for a 12-inch wafer. Further, when picking up an 8-inch wafer, the gravity difference between the first branch component and the second branch component is set to 2g, and when picking up a 12-inch wafer, the gravity difference is set to 4g.

[0034] S5, if not, the robotic arm is driven by a translation mechanism to reverse the displacement of the wafer to be picked up. Specifically, the wafer picked up by the first branch component and the second branch component is transferred to the next process equipment.

[0035] S6, if yes, return to step S3. Taking 8-inch and 12-inch wafers as examples, if the gravity difference between the first branch component and the second branch component is greater than the above threshold of 2g or 4g, it indicates that there is a precision deviation in wafer picking or that the wafer has uneven electroplating. Return to step S3 and repeat step S4 to determine if the gravity difference is reduced to less than the threshold, indicating that the picking precision has reached the standard and the wafer can be moved. If repeating steps S3 and S4 still results in a gravity difference greater than the threshold, there may be an uneven wafer electroplating problem, and the wafer can be inspected.

[0036] The above steps are detailed in conjunction with the aforementioned implementation methods and will not be repeated here.

[0037] The detailed descriptions listed above are merely specific descriptions of feasible embodiments of the present invention, and are not intended to limit the scope of protection of the present invention. All equivalent embodiments or modifications made without departing from the spirit of the present invention should be included within the scope of protection of the present invention.

[0038] It will be apparent to those skilled in the art that the present 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 its spirit or essential characteristics. Therefore, the embodiments should be considered in all respects as exemplary and non-limiting, and the scope of the invention is defined by the appended claims rather than the foregoing description. Thus, all variations falling within the meaning and scope of equivalents of the claims are intended to be included within the present invention. No reference numerals in the claims should be construed as limiting the scope of the claims.

[0039] Furthermore, it should be understood that although this specification describes embodiments, not every embodiment contains only one independent technical solution. This narrative style is merely for clarity. Those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

Claims

1. A wafer transfer device, characterized in that, include: The translation mechanism and the robotic arm are provided. The robotic arm picks up the wafer through a first branch component and a second branch component that are symmetrically distributed at its end. The first branch component and the second branch component are connected to one end of the connecting component in the length direction of the robotic arm. The end of the connecting component away from the first branch component and the second branch component is connected to the translation mechanism through a support frame. The connecting member is equipped with a gravity sensor, which is electrically connected to the first branch member and the second branch member respectively.

2. The wafer transfer device according to claim 1, characterized in that, The robotic arm has a first robotic arm and a second robotic arm arranged coaxially, and the support frame includes a first support frame and a second support frame. The top ends of the first support frame and the second support frame are respectively connected to the connecting members of the first robotic arm and the second robotic arm.

3. The wafer transfer device according to claim 2, characterized in that, The first support frame includes a first connecting plate, a second connecting plate, and a third connecting plate. One end of the first connecting plate in the length direction is connected to the drive end of the translation mechanism. The other end of the first connecting plate extends away from the translation mechanism and is vertically fixed to the second connecting plate. The top of the second connecting plate is vertically upward and connected to one end of the third connecting plate in the length direction. The end of the third connecting plate away from the second connecting plate is connected to the first robotic arm. The second support frame includes a connecting seat and a support rod. One end of the connecting seat is connected to the other drive end of the translation mechanism. The support rod is vertically fixed to the upper surface of the connecting seat, and the second robotic arm is mounted on the top of the support rod.

4. The wafer transfer device according to claim 3, characterized in that, The lower surface of the first branch component is provided with a first suction cup and a second suction cup along the length direction, and the lower surface of the second branch component is provided with a third suction cup and a fourth suction cup along the length direction. The first suction cup, the second suction cup, the third suction cup and the fourth suction cup are simultaneously attached to the upper surface of the wafer. The first branch component and the second branch component are integrally formed to form an air passage that communicates with the first suction cup, the second suction cup, the third suction cup and the fourth suction cup.

5. The wafer transfer device according to claim 4, characterized in that, The connecting component includes a connecting rod body, a first connecting part, and a second connecting part, wherein the first connecting part and the second connecting part are formed at both ends of the connecting rod body; The first connecting part is attached and fixed to the connection between the first supporting member and the second branch member, and the end of the first connecting part away from the main body of the connecting rod forms an air inlet that communicates with the air passage.

6. The wafer transfer device according to claim 5, characterized in that, The gravity sensor is mounted on the upper surface of the connecting rod body and is optionally a thin-film gravity sensor; The air passage is formed on the upper surface of the first branch member and the second branch member and sealed by a cover of the same shape. The first branch member and the second branch member are electrically connected to the gravity sensor through the cover.

7. The wafer transfer device according to claim 4, characterized in that, The ends of the first branch member and the second branch member away from the connecting member are respectively formed into arc shapes, and the connection between the first branch member and the second branch member is a rounded transition.

8. The wafer transfer device according to claim 5, characterized in that, A rotating device is fixed to the top of the third connecting plate and the support rod, respectively, and the second connecting parts of the two connecting members are respectively connected to the driving ends of the two rotating members.

9. A wafer picking method, characterized in that, Based on the wafer transfer device according to any one of claims 1 to 8, the process includes the following steps: S1, the translation mechanism drives the robotic arm to move toward the wafer to be picked up; S2, when the robotic arm moves to a position where the first branch component and the second branch component are symmetrically located on both sides of the diameter direction of the wafer to be picked up, the translation mechanism is stopped; S3, picking up the wafer through the first branch component and the second branch component; S4, determine whether the difference in gravity from the wafer between the first branch component and the second branch component is greater than a threshold value using the gravity sensor; S5, if not, drive the robotic arm to reverse the displacement of the wafer to be picked up through the translation mechanism; S6, if yes, return to step S2.

10. The wafer pickup method according to claim 9, characterized in that, Also includes: The threshold is set based on the wafer size.

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