Wafer release method

Abstract

This invention discloses a wafer release method for use in a wafer processing system and a wafer processing method. The wafer release method of this invention includes: a polarity reversal step of reversing the polarity of a voltage applied to a chuck; a first transfer step of raising a lifting pin housed in the chuck at a first transfer speed to transfer a wafer supported on the chuck to a first predetermined position; and a second transfer step of raising the lifting pin at a second transfer speed different from the first transfer speed to transfer the wafer positioned at the first predetermined position to a second predetermined position higher than the first predetermined position.

Description

Technical Field

[0001] This invention relates to a wafer release method, and more specifically, to a wafer release method for releasing a wafer from an electrostatic chuck holding a wafer product in a semiconductor manufacturing process system. Background Technology

[0002] Typically, chucks used in semiconductor manufacturing processes generate static electricity when voltage is applied, thereby securing the wafers supported on them.

[0003] However, the problem with the electrostatic chuck described above is that the wafer is held in place by electrostatic force. As a result, when the wafer is to be separated from the chuck using lifting pins, it is not easy to separate the wafer due to the electrostatic force acting between the chuck and the wafer.

[0004] That is, the problem is that when the wafer is separated from the chuck by using the lifting pin to support it, the electrostatic force between the chuck and the wafer generates a large resistance, which causes the wafer to detach from the lifting pin.

[0005] Therefore, in order to solve the problems mentioned above, a method has been developed that reverses the polarity of the voltage applied to the chuck to discharge residual charge and thereby remove the electrostatic force between the chuck and the wafer to separate the wafer from the chuck.

[0006] However, the problem is that even if the polarity of the voltage applied to the chuck is reversed to discharge the charge, complete discharge is not possible, leaving some electrostatic force between the chuck and the wafer. As a result, the wafer may detach from the lifting pin or tilt during wafer separation, and the wafer may be damaged. Summary of the Invention

[0007] Technical issues

[0008] The purpose of this invention is to provide a wafer release method that completely discharges the residual charge between the chuck and the wafer, so as to prevent the wafer from detaching from the lifting pin or tilting due to the influence of residual charge during wafer separation, as well as the problem of wafer damage, and to minimize the defect rate.

[0009] Technical solution

[0010] An embodiment of the wafer release method of the present invention includes: a polarity reversal step of reversing the polarity of a voltage applied to a chuck; a first transfer step of raising a lifting pin housed in the chuck at a first transfer speed to transfer a wafer supported on the chuck to a first predetermined position; and a second transfer step of raising the lifting pin at a second transfer speed different from the first transfer speed to transfer the wafer disposed at the first predetermined position to a second predetermined position higher than the first predetermined position.

[0011] The second set position can be the position where the wafer is transported.

[0012] The first transfer speed can be slower than the second transfer speed.

[0013] The ratio of the first transfer speed to the second transfer speed can be from 1:2 to 1:5.

[0014] The distance from the chuck to the first predetermined position can be shorter than the distance from the chuck to the second predetermined position.

[0015] The ratio of the first distance from the chuck to the first set position to the second distance from the chuck to the second set position can be 1:4 to 1:6.

[0016] The wafer can be continuously moved from the first set position to the second set position.

[0017] Another embodiment of the wafer release method of the present invention includes: a polarity reversal step of reversing the polarity of a voltage applied to a chuck; a first transfer step of raising a lifting pin housed in the chuck at a first transfer speed to transfer a wafer supported on the chuck to a first predetermined position; a third transfer step of lowering the lifting pin at a third transfer speed to transfer the wafer disposed at the first predetermined position to a third predetermined position lower than the first predetermined position; and a second transfer step of raising the lifting pin at a second transfer speed different from the first transfer speed and the third transfer speed to transfer the wafer disposed at the third predetermined position to a second predetermined position higher than the first predetermined position.

[0018] The third transfer speed can be the same as the first transfer speed or a faster speed than the first transfer speed.

[0019] The ratio of the first transfer speed to the second transfer speed can be from 1:2 to 1:5, and the ratio of the third transfer speed to the second transfer speed can be from 1:2 to 1:5.

[0020] The third set position can be the position where the wafer is supported on the chuck.

[0021] During the process of the wafer supported on the chuck being moved to the first set position, a flow path is formed between the chuck and the wafer. During the process of the wafer positioned at the first set position being moved to the third set position, fluid supplied from the top of the wafer and discharged from a position lower than the wafer can contact the top of the chuck and the bottom of the wafer when passing through the flow path.

[0022] At least one of the first transfer step and the second transfer step may include multiple intervals in which the speed can be gradually or intermittently increased to a faster speed.

[0023] Before the wafer is moved to a position above the first set position, fluid supplied from the top of the wafer can be discharged from a position below the wafer.

[0024] When the wafer transfer speed is changed, at least one of the fluid's capacity and pressure can be changed.

[0025] The effects of the invention

[0026] According to an embodiment of the present invention, when the wafer is separated from the chuck, the wafer is moved slowly and steadily to minimize the effect of residual charge remaining between the wafer and the chuck on the wafer. This prevents the wafer from detaching from the lifting pin or tilting due to the effect of residual charge, as well as wafer damage, and minimizes the defect rate.

[0027] Furthermore, as the wafer is slowly separated from the chuck, a flow path is formed between the chuck and the wafer, allowing the fluid supplied to the chamber to flow between the chuck and the wafer, thereby enabling the residual charge to be completely discharged.

[0028] At the same time, when the wafer is moved to the first set position unaffected by electrostatic forces, the wafer is moved to the second set position at a faster speed to shorten the process time, thereby minimizing the loss of throughput.

[0029] The effects of the present invention are not limited to the above-described examples, but rather include a wider variety of effects. Attached Figure Description

[0030] Figure 1 This is a diagram schematically illustrating the wafer release process according to an embodiment of the present invention.

[0031] Figure 2 This is a sequence diagram illustrating a wafer release method according to an embodiment of the present invention.

[0032] Figure 3 This is a diagram schematically illustrating a variable-speed process during wafer release according to an embodiment of the present invention.

[0033] Figure 4 This is a diagram schematically illustrating the wafer release process according to another embodiment of the present invention.

[0034] Figure 5 This is a sequence diagram illustrating a wafer release method according to another embodiment of the present invention.

[0035] Figure Labels

[0036] 100: Wafer processing device, 10: Chamber, 20: Chuck, 30: Lifting pin, W: Wafer. Detailed Implementation

[0037] The embodiments of the present invention will now be described in detail with reference to the accompanying drawings, so that those skilled in the art can easily implement the invention.

[0038] This invention can be implemented in many different forms, and is not limited to the embodiments described herein.

[0039] Reference Figure 1 In one embodiment of the present invention, the wafer release process is performed by the wafer processing apparatus 100 of a semiconductor manufacturing system.

[0040] The wafer processing apparatus 100 is configured to handle the loading and unloading of wafer W via a robotic arm (not shown), and includes a chamber 10 serving as a space for processing wafer W, a chuck 20 disposed within the chamber 10 and configured to fix or release wafer W according to the polarity of the applied DC voltage, and a lifting pin 30 housed inside the chuck 20 and configured to raise and lower wafer W. However, the wafer processing apparatus 100 is not necessarily limited to this and may further include various components.

[0041] A wafer release method according to an embodiment of the present invention will be described in more detail.

[0042] A wafer release method according to an embodiment of the present invention may include a polarity reversal step (S110), a first transfer step (S120), and a second transfer step (S130).

[0043] Reference Figure 1 (a) and Figure 2 When the processing step of wafer W is completed, the wafer processing apparatus 100 may perform a polarity reversal step (S110) to reverse the polarity of the voltage applied to the chuck 20.

[0044] That is, after the wafer processing apparatus 100 completes the processing step of wafer W, it reverses the polarity of the voltage applied to chuck 20 so that the wafer W fixed to chuck 20 can be separated from chuck 20. For example, the polarity of the DC voltage applied to chuck 20 before performing the wafer W processing step can be +, and the polarity of the DC voltage applied to chuck 20 after performing the wafer W processing step can be -. However, the polarity of the DC voltage applied to chuck 20 before performing the wafer W processing step and the polarity of the DC voltage applied to chuck 20 after performing the wafer W processing step are not necessarily limited to these, and can be applied with opposite polarities.

[0045] Reference Figure 1 (b) and Figure 2 When the polarity of the voltage applied to the chuck 20 is reversed, the wafer processing apparatus 100 can cause the lifting pin 30 housed in the chuck 20 to rise from the chuck 20 at a first transfer speed to perform a first transfer step (S120) of transferring the wafer W supported on the chuck 20 to a first set position P1. Although not shown in the figure, a drive device (not shown) may be further configured to be combined with the lifting pin 30 and configured to raise and lower the lifting pin 30. For example, the drive device may be implemented as an actuator such as a motor or cylinder.

[0046] Reference Figure 1 (c) and Figure 2 When the wafer W is moved to the first set position P1, the wafer processing device 100 can raise the lifting pin 30 at a second transfer speed different from the first transfer speed to perform a second transfer step (S130) to move the wafer W arranged at the first set position P1 to a second set position P2 higher than the first set position P1.

[0047] That is, such as Figure 1 As shown, when the wafer W is moved to the first set position P1, the wafer processing device 100 causes the lifting pin 30 to rise at a second transfer speed different from the first transfer speed to move the wafer W arranged at the first set position P1 to the position where the wafer W is transported by the robotic arm (not shown), namely the second set position P2.

[0048] Therefore, in this embodiment, when the wafer W is separated from the chuck 20, the wafer W is moved slowly and steadily to minimize the effect of the electrostatic force remaining between the wafer W and the chuck 20 on the wafer W. This can prevent the wafer W from detaching from the lifting pin 30 or tilting due to the effect of electrostatic force, as well as prevent the wafer W from being damaged, and can minimize the defect rate.

[0049] At this time, the first conveying speed of the lifting pin 30 can be slower than the second conveying speed of the lifting pin 30.

[0050] That is, in order to prevent the influence of residual charge remaining between wafer W and chuck 20 from affecting wafer W, wafer processing apparatus 100 moves wafer W supported on chuck 20 to first set position P1 at a first transfer speed that is relatively slower than the second transfer speed. When wafer W reaches the first set position P1, in order to speed up the process, wafer W is moved to second set position P2 at the second transfer speed.

[0051] More specifically, the ratio of the first transfer speed to the second transfer speed can be from 1:2 to 1:5. For example, the drive pulse of the drive device (not shown) that causes the lifting pin 30 to move up and down at the first transfer speed can be set to 8,000 to 15,000. Additionally, the drive pulse of the drive device (not shown) that causes the lifting pin 30 to move up and down at the second transfer speed can be set to 16,000 to 75,000.

[0052] Furthermore, the first distance d1 from the chuck 20 to the first set position P1 can be shorter than the second distance d2 from the chuck 20 to the second set position P2. For example, the first set position P1 can be the position where the wafer W supported by the lifting pin 30 rises from the chuck 20 at a first transfer speed for 5 to 20 seconds.

[0053] More specifically, the ratio of the first distance d1 from the chuck 20 to the first set position P1 to the second distance d2 from the chuck 20 to the second set position P2 can be 1:4 to 1:6.

[0054] At this time, the wafer W is continuously moved from the first set position P1 to the second set position P2. That is, when moving from the first set position P1 to the second set position P2, the moving speed can be changed without stopping.

[0055] Reference Figure 1 and Figure 3 At least one of the processes of moving wafer W from chuck 20 to a first set position P1 and moving wafer W from the first set position P1 to a second set position P2 may include multiple intervals in which the transfer speed of wafer W can be gradually or intermittently increased.

[0056] That is, in at least one of the processes of the wafer W being moved from the chuck 20 to the first set position P1 and the wafer W being moved from the first set position P1 to the second set position P2, the lifting pin 30 can gradually increase the transfer speed of the wafer W, or the lifting pin 30 can increase the transfer speed of the wafer W in intervals by dividing it into multiple intervals.

[0057] For example, refer to the diagram showing the process of moving from the first set position P1 to the second set position P2. Figure 3The lifting pin 30 can gradually increase its rising speed to move the wafer W positioned at the first set position P1 to the second set position P2 more quickly. For reference, in Figure 3 In the diagram, the arrows on both sides of wafer W represent the transfer speed of wafer W. The thickness of the arrow indicates the rate of transfer. That is, it can represent... Figure 3 The wafer W shown in (b) has a transfer speed that is greater than that of the wafer W. Figure 3 The wafer W shown in (a) has a fast transfer speed, and Figure 3 The wafer W shown in (c) has a transfer speed ratio that is higher than that of the wafer W. Figure 3 The wafer W shown in (b) has a fast transfer speed.

[0058] Therefore, in this embodiment, when the wafer W is moved to the first set position P1 which is not affected by electrostatic force, the wafer W can be continuously moved to the second set position P2 at a faster speed to shorten the process time, thereby minimizing the loss of throughput.

[0059] In addition, it may include multiple intervals that progressively or intermittently increase the transfer speed of wafer W to a faster speed, so that wafer W can be transferred stably.

[0060] On the other hand, fluid supplied from the top of wafer W can be discharged from a position below wafer W. In this case, fluid can be supplied at least before wafer W is moved to a position above the first set position P1, and if necessary, it can also be supplied during the process of wafer W being moved to the second set position P2.

[0061] At this point, the fluid combines with the residual charge remaining between the wafer W and the chuck 20 and is discharged, thus allowing the residual charge to be completely discharged.

[0062] For example, the fluid can be an inert gas or a near-inert gas. Specifically, the fluid can be formed from argon (Ar) series or nitrogen (N2) series.

[0063] On the other hand, when the transfer speed of wafer W changes, at least one of the volume and pressure of the fluid supplied to the interior of chamber 10 can be changed. For example, the fluid volume can be changed from 50 to 500 sccm. Additionally, the fluid pressure can be changed from 5 to 1000 mT.

[0064] Specifically, as the transfer speed of wafer W increases, the magnitude of at least one of the fluid volume and pressure can decrease. For example, the magnitude of at least one of the fluid volume and pressure during the process of wafer W being transferred from the first set position P1 to the second set position P2, compared to the magnitude of at least one of the fluid volume and pressure during the process of wafer W being spaced apart from chuck 20 and transferred to the first set position P1, can be smaller.

[0065] In this way, as the transfer speed of wafer W increases, the size of at least one of the fluid capacity and pressure can be reduced, so that wafer W can be transferred stably.

[0066] The wafer release method according to another embodiment of the present invention will now be described.

[0067] For reference, for ease of description, the reference numerals used in describing the wafer release method of another embodiment of the present invention will be used in the same way for each component, and the same or repeated descriptions will be omitted.

[0068] Another embodiment of the wafer release method of the present invention may include a polarity reversal step (S210), a first transfer step (S220), a third transfer step (S230), and a second transfer step (S240).

[0069] Reference Figure 4 (a) and Figure 5 When the processing step of wafer W is completed, the wafer processing apparatus 100 may perform a polarity reversal step (S210) to reverse the polarity of the voltage applied to the chuck 20.

[0070] Reference Figure 4 (b) and Figure 5 When the polarity of the voltage applied to the chuck 20 is reversed, the wafer processing apparatus 100 can cause the lifting pin 30 housed in the chuck 20 to rise from the chuck 20 at a first transfer speed, and perform a first transfer step (S220) to transfer the wafer W supported on the chuck 20 to a first set position P1.

[0071] Reference Figure 4 (c) and Figure 5 When the wafer W is moved to the first set position P1, the wafer processing device 100 can lower the lifting pin 30 at a third transfer speed to perform a third transfer step (S230) to move the wafer W arranged at the first set position P1 to a third set position P3 lower than the first set position P1.

[0072] Reference Figure 4 (d) and Figure 5When the wafer W is moved to the third set position P3, the wafer processing apparatus 100 can raise the lifting pin 30 at a second transfer speed different from the first transfer speed and the third transfer speed to perform a second transfer step (S240) to move the wafer W arranged at the third set position P3 to the second set position P2 which is higher than the first set position P1.

[0073] At this time, the third conveying speed of the lifting pin 30 can be the same as or faster than the first conveying speed of the lifting pin 30. Alternatively, the first and third conveying speeds of the lifting pin 30 can be slower than the second conveying speed of the lifting pin 30.

[0074] More specifically, the ratio of the first transfer speed to the second transfer speed can be from 1:2 to 1:5, and the ratio of the third transfer speed to the second transfer speed can be from 1:2 to 1:5.

[0075] In addition, the first set position P1 can be a position where the wafer W is not affected by the residual charge remaining between the wafer W and the chuck 20, the second set position P2 can be a position where the wafer W is transported by a robotic arm (not shown), and the third set position P3 can be a position where the wafer W is supported on the chuck 20.

[0076] That is, such as Figure 4 As shown, when the processing step of wafer W is completed, in order to prevent the residual charge remaining between wafer W and chuck 20 from affecting wafer W, the wafer processing apparatus 100 moves the wafer W supported on chuck 20 to a first set position P1 at a first transfer speed that is relatively slower than the second transfer speed. Then, when wafer W reaches the first set position P1, the wafer processing apparatus 100 moves the wafer W positioned at the first set position P1 to a third set position P3 at a third transfer speed that is the same as or faster than the first transfer speed, in a manner that keeps wafer W supported on chuck 20. Then, when wafer W reaches the third set position P3, for a faster process, the wafer processing apparatus 100 moves the wafer W positioned at the third set position P3 to a second set position P2 for transporting wafer W at a second transfer speed that is faster than both the first and third transfer speeds.

[0077] Therefore, in this embodiment, the wafer W is moved slowly when it is moved to the first set position P1 or the third set position P3, so as to adjust the wafer W to be more stably supported on the lifting pin 30, thereby allowing the wafer W to rise stably to the second set position P2.

[0078] Furthermore, in this embodiment, before the wafer W supported on the chuck 20 is moved to the second set position P2, it is lowered to the third set position P3 after rising to the first set position P1, so that the residual charge remaining between the wafer W and the chuck 20 can be completely discharged.

[0079] Furthermore, in this embodiment, during the process of moving the wafer W supported on the chuck 20 to the first set position P1, a flow path FP is formed between the chuck 20 and the wafer W. During the process of moving the wafer W arranged in the first set position P1 to the third set position P3, fluid supplied from the upper part of the wafer W and discharged from a position lower than the wafer W comes into contact with the upper part of the chuck 20 and the lower part of the wafer W when it passes through the flow path FP. As the wafer W is moved to the third set position P3, the height of the flow path FP gradually decreases, which speeds up the flow of fluid and thus allows the residual charge between the wafer W and the chuck 20 to be discharged more quickly.

[0080] Furthermore, in this embodiment, the wafer W can be moved to the second set position P2 at a relatively faster speed than when the wafer W is moved to the first set position P1 and the third set position P3, thereby shortening the process time.

[0081] Although not illustrated, the distance from chuck 20 to the first set position P1 can be made shorter than the distance from chuck 20 to the second set position P2.

[0082] Furthermore, at least one of the processes of moving wafer W from chuck 20 to a first set position P1, moving wafer W from the first set position P1 to a third set position P3, and moving wafer W from the third set position P3 to a second set position P2 may include multiple intervals in which the transfer speed of wafer W can be gradually or intermittently increased.

[0083] On the other hand, fluid supplied from the top of wafer W can be discharged from a position below wafer W. In this case, fluid can be supplied at least before wafer W is moved to a position above the first set position P1, and if necessary, it can also be supplied during the process of moving to the second set position P2.

[0084] At this point, the fluid combines with the residual charge remaining between the wafer W and the chuck 20 and is discharged, thus allowing the residual charge to be completely discharged.

[0085] For example, the fluid can be an inert gas or a near-inert gas. Specifically, the fluid can be formed from argon (Ar) series or nitrogen (N2) series.

[0086] On the other hand, when the transfer speed of wafer W changes, at least one of the volume and pressure of the fluid supplied to the interior of chamber 10 can be changed. For example, the fluid volume can be changed from 50 to 500 sccm. Additionally, the fluid pressure can be changed from 5 to 1000 mT.

[0087] Specifically, as the transfer speed of wafer W increases, the magnitude of at least one of the fluid volume and pressure can decrease. For example, the magnitude of at least one of the fluid volume and pressure during the process of wafer W being transferred from the third set position P3 to the second set position P2 can be smaller than the magnitude of the fluid volume and pressure during the process of wafer W being transferred from the first set position P1 to the third set position P3, which is spaced apart from chuck 20.

[0088] In this way, as the transfer speed of wafer W increases, the size of at least one of the fluid capacity and pressure can be reduced, so that wafer W can be transferred stably.

[0089] Although the invention has been described in detail above with reference to preferred embodiments, the invention is not limited thereto, but can be implemented in various ways within the scope of the claims.

Claims

1. A wafer release method, characterized in that, include: A polarity reversal step that reverses the polarity of the voltage applied to the chuck; A first transfer step in which a lifting pin housed in the chuck rises from the chuck at a first transfer speed to transfer a wafer supported on the chuck to a first predetermined position; A third transfer step involves lowering the lifting pin at a third transfer speed to transfer the wafer positioned at the first set position to a third set position lower than the first set position. as well as A second transfer step involves raising the lifting pin at a second transfer speed different from the first and third transfer speeds to transfer the wafer positioned at the third set position to a second set position higher than the first set position.

2. The wafer release method according to claim 1, characterized in that, The second designated position is the position where the wafer is transported.

3. The wafer release method according to claim 1, characterized in that, The first transfer speed is slower than the second transfer speed.

4. The wafer release method according to claim 3, characterized in that, The ratio of the first transfer speed to the second transfer speed is 1:2 to 1:

5.

5. The wafer release method according to claim 1, characterized in that, The distance from the chuck to the first predetermined position is shorter than the distance from the chuck to the second predetermined position.

6. The wafer release method according to claim 5, characterized in that, The ratio of the first distance from the chuck to the first set position to the second distance from the chuck to the second set position is 1:4 to 1:

6.

7. The wafer release method according to claim 1, characterized in that, The third transfer speed is the same as or faster than the first transfer speed.

8. The wafer release method according to claim 7, characterized in that, The ratio of the third transfer speed to the second transfer speed is 1:2 to 1:

5.

9. The wafer release method according to claim 1, characterized in that, The third designated position is the position where the wafer is supported on the chuck.

10. The wafer release method according to claim 1, characterized in that, During the process of the wafer supported by the chuck being moved to the first predetermined position, a flow path is formed between the chuck and the wafer. During the process of the wafer positioned at the first predetermined position being moved to the third predetermined position, fluid supplied from the top of the wafer and discharged from a position below the wafer comes into contact with the top of the chuck and the bottom of the wafer as it passes through the flow path.

11. The wafer release method according to claim 1, characterized in that, At least one of the first transfer step and the second transfer step includes multiple intervals in which the speed gradually or intermittently increases.

12. The wafer release method according to any one of claims 1 to 10, characterized in that, Before the wafer is moved to a position above the first set position, fluid supplied from the top of the wafer is discharged from the wafer to a position below the wafer.

13. The wafer release method according to claim 12, characterized in that, When the wafer transfer speed changes, at least one of the fluid's capacity and pressure changes.

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