Substrate processing apparatus and substrate detaching method

Abstract

To accurately determine a suction state of a substrate by an electrostatic chuck when separating the substrate after high-temperature treatment, and to reduce a breakage risk when separating the substrate.SOLUTION: The substrate processing apparatus WD includes an electrostatic chuck E for attracting and supporting a substrate W to be subjected to high temperature processing, a separation device F for separating the substrate W supported by the electrostatic chuck E, and a control device C for applying a separation voltage to the electrostatic chuck E when the substrate W is physically separated by the separation device F. The control device C determines the suction state of the substrate W based on the load of the separation device F.SELECTED DRAWING: Figure 6

Description

[Technical Field]

[0001] The present invention relates to a substrate processing apparatus equipped with an electrostatic chuck and a method for removing a substrate from the electrostatic chuck in the substrate processing apparatus. [Background technology]

[0002] In substrate processing equipment such as a film deposition apparatus, a dry etching apparatus, or an ion implantation apparatus, a substrate is subjected to a predetermined process while being supported by an electrostatic chuck. After the substrate processing is completed, the substrate is released from the electrostatic chuck. After the release, the substrate is transported along a predetermined path and stored in a cassette or the like.

[0003] After the substrate processing, when the substrate is to be released from the electrostatic chuck, a release voltage is applied to the electrostatic chuck in order to remove residual charge generated between the substrate and the electrostatic chuck. The residual attraction force does not disappear instantly when a release voltage is applied, but decreases over time.

[0004] If a substrate is forcibly released from an electrostatic chuck while a relatively large residual attracting force remains, various problems such as cracking, bouncing, and displacement of the substrate may occur. The residual attracting force can be reduced by setting the elapsed time after application of the release voltage to a sufficiently long time. However, in this case, the processing capacity of the substrate processing apparatus may be reduced.

[0005] Therefore, Patent Document 1 proposes a method for releasing a substrate from an electrostatic chuck at an appropriate timing based on the measurement results of a sensor. Specifically, a plurality of laser displacement sensors and capacitance sensors are installed facing the substrate surface in the substrate release direction, and these sensors are used to monitor the substrate's chuck state. Based on the results of the chuck state monitoring, the substrate is released from the electrostatic chuck at a timing when the chuck state becomes suitable for releasing the substrate.

[0006] However, the substrate held by the electrostatic chuck is not necessarily flat. For example, the substrate surface may contain minute irregularities or may be slightly inclined. Furthermore, the temperature characteristics of the substrate processing and the electrostatic chuck supporting the substrate may cause the temperature distribution within the substrate surface to be uneven. As a result, localized distortion occurs within the substrate surface, which may lead to warping of the substrate. In particular, in substrate processing apparatuses that perform high-temperature processing on substrates, the substrates tend to be significantly warped.

[0007] When the substrate is significantly warped, the entire substrate may be supported by the electrostatic chuck, with some areas supported by the electrostatic chuck and some areas not supported by the electrostatic chuck. In this case, the substrate and the electrostatic chuck are in partial contact with each other, and the contacting areas are attracted to the electrostatic chuck. When the substrate is supported in this manner, the method of Patent Document 1, which uses a sensor to monitor the attraction state between the substrate and the electrostatic chuck, may result in an erroneous determination of the attraction state. This erroneous determination occurs because, even if the entire substrate is attracted to the electrostatic chuck, the portion of the substrate facing the sensor is not in contact with the electrostatic chuck, and therefore the substrate is determined to be detached from the electrostatic chuck. In order to avoid such misjudgments, it is conceivable to increase the number of sensors, but this would result in various problems, such as increased costs due to the addition of sensors, limitations on sensor placement locations, and increased complexity of signal processing.

[0008] Patent Document 2 proposes a method in which a force sensor is mounted on a lift-up pin used when releasing a substrate, and the attracted state of the substrate is determined from the results of measuring the load applied to the force sensor. Specifically, after the substrate attracting voltage applied by the electrostatic chuck is stopped, the lift-up pin is raised and the attracted state of the substrate is determined based on the load measured by the force sensor. In Patent Document 2, the attracted state of the substrate is determined by physically pressing the substrate, so it is possible to correctly determine the attracted state of the substrate even if the substrate is only partially supported by the electrostatic chuck. [Prior art documents] [Patent documents]

[0009] [Patent Document 1] Patent Publication No. 2019-117926 [Patent Document 2] Patent Publication No. 2008-187106 Summary of the Invention [Problem to be solved by the invention]

[0010] Patent Document 2 proposes reducing the residual chucking force by using a push-up pin to slightly push up the edge of the substrate from the electrostatic chuck after stopping the chucking voltage. However, when the edge of the substrate is to be released from the electrostatic chuck while most of the substrate is still attached to the electrostatic chuck by the residual attraction force, a large force must be applied to the edge of the substrate during the initial lift-up operation, which may result in damage to the edge of the substrate.

[0011] The main object of the present invention is to accurately determine the state of attraction of a substrate by an electrostatic chuck when the substrate is released after high-temperature processing, thereby reducing the risk of damage to the substrate when it is released. [Means for solving the problem]

[0012] The substrate processing apparatus includes: an electrostatic chuck for adsorbing and supporting a substrate to be processed at high temperature; a de-chuck configured to de-chuck the substrate supported by the electrostatic chuck; a control device that applies a de-chuck voltage to the electrostatic chuck when the de-chuck device physically de-chucks the substrate, The control device determines the suction state of the substrate based on the load on the desorption device.

[0013] The method for removing the substrate is as follows: supporting the substrate to be subjected to high temperature processing by electrostatic chuck; physically removing the substrate from the electrostatic chuck after high temperature processing of the substrate; applying a desorption voltage to the electrostatic chuck when physically desorbing the substrate; and determining the suction state of the substrate based on the load applied when physically removing the substrate.

[0014] The system employs a configuration that determines the suction state of the substrate based on the load applied when the substrate is released, making it possible to accurately determine the suction state of the substrate even if the substrate is significantly warped due to high-temperature processing. Furthermore, when physically removing the substrate, applying a removal voltage reduces the residual attraction force generated between the substrate and the electrostatic chuck, thereby reducing the force applied to the substrate during removal, thereby reducing the risk of damage to the substrate during removal. [Effects of the Invention]

[0015] The system employs a configuration that determines the suction state of the substrate based on the load applied when the substrate is released, making it possible to accurately determine the suction state of the substrate even if the substrate is significantly warped due to high-temperature processing. Furthermore, when physically removing the substrate, applying a removal voltage reduces the residual attraction force generated between the substrate and the electrostatic chuck, thereby reducing the force applied to the substrate during removal, thereby reducing the risk of damage to the substrate during removal. [Brief explanation of the drawings]

[0016] [Figure 1] Schematic plan view of a substrate processing apparatus [Figure 2] Diagram of the injection mechanism [Figure 3] Illustration of the board delivery position [Figure 4] Explanation of the substrate removal operation [Figure 5] Plan view of Figure 4 from a different plane [Figure 6] Explanation of the substrate removal operation [Figure 7]Explanation of the substrate removal operation [Figure 8] Relationship between release voltage and adhesion voltage [Figure 9] Flowchart for substrate removal method [Figure 10] Schematic plan view of another substrate processing apparatus. DETAILED DESCRIPTION OF THE INVENTION

[0017] Film deposition equipment, dry etching equipment, and ion implantation equipment are known as substrate processing equipment that performs a predetermined process on a substrate while it is supported on an electrostatic chuck. Figure 1 shows the configuration of the processing chamber and surrounding area of ​​an ion implantation equipment as a typical example of a substrate processing equipment WD. Cassettes 7a-7d store a plurality of substrates W. The substrates W are made of SiC, Si, or the like and have a circular outer shape in plan view, and are provided with a mark on the periphery to indicate a reference position, such as a notch or an orientation flat. However, the type and shape of the substrates W are not limited to this. For example, they may be glass substrates that are rectangular in plan view.

[0018] The atmospheric robots 4a and 4b take out the substrates W from the cassettes 7a-7d and transport them to the aligner 5. After the circumferential position of the substrates W is adjusted by the aligner 5, the atmospheric robots 4a and 4b transport the substrates W to the vacuum spare chambers 3a and 3b. The spare vacuum chambers 3a and 3b enable the substrate W to be transported between the processing chamber 1 and the room where the aligner 5 is located by switching the degree of vacuum in the chambers. The floors of the vacuum preparatory chambers 3a and 3b are moved in the front-to-back direction of the drawing by a drive mechanism (not shown). The floors are moved after the chambers are switched from atmosphere to vacuum or from vacuum to atmosphere.

[0019] The processing chamber 1 is equipped with vacuum hands V1 and V2 that can independently rotate in the directions of the arrows shown in the figure. The vacuum hands V1 and V2 are equipped with gripping portions C1 and C2 that grip the periphery of the substrate W. The vacuum hands V1 and V2 grip the substrate W in the vacuum auxiliary chambers 3a and 3b and transport it to the platen 2.

[0020] FIG. 2 illustrates the process of ion implantation on a substrate W supported on a platen 2. A drive shaft 12 is attached to the platen 2, which reciprocates the platen 2 in the Y-axis direction by a drive source D1 (scan motor). The ion beam IB shown in FIG. 2 is an ion beam whose cross section in the XY plane is spot-shaped. This ion beam IB is scanned in a direction parallel to the X-axis direction by electrostatic or magnetic fields. The scanning width of the ion beam IB at this time is equal to or greater than the diameter of the substrate W.

[0021] The platen 2 includes an electrostatic chuck E that attracts and supports the substrate W, and a heater H that heats the substrate W to a high temperature during substrate processing. The circumferential position of the substrate W attracted and supported by the electrostatic chuck E is adjusted by a twist mechanism (not shown). In addition, a drive source D2 (tilt motor) that drives a tilt mechanism (not shown) rotates the platen 2 around an axis parallel to the X-axis, thereby adjusting the irradiation angle of the ion beam IB onto the substrate W.

[0022] After the attitude of the platen 2 is adjusted, the drive shaft 12 reciprocates, whereby the surface to be processed of the substrate W moves across the ion beam IB, and ion implantation processing is performed on the substrate W. Note that instead of the above-described ion beam IB, a ribbon-shaped ion beam having a substantially rectangular cross section in the XY plane may be used. In this case, the dimension of the ion beam IB in the X-axis direction is larger than the dimension of the substrate W in the same direction. Furthermore, scanning of the ion beam IB in a direction parallel to the X-axis is not required.

[0023] 3 shows the position of the platen 2 when the substrate W is transferred. When the substrate W is transferred, the drive source D2 rotates the platen 2, and the position of the platen 2 becomes horizontal. 2 and 3 is configured to rotate the platen 2 about an axis parallel to the X axis, but it may also be configured to rotate the platen 2 about an axis parallel to the Y axis. In that case, a separate drive source is provided to keep the platen 2 in a horizontal position, and the substrate W is transferred.

[0024] The configuration of the ion implantation apparatus described in FIGS. 1 to 3 is an example, and the present invention is not limited to the configurations depicted in the figures. For example, the numbers of vacuum hands V1, V2, vacuum spare chambers 3a, 3b, atmospheric robots 4a, 4b, and cassettes 7a-7d are not limited to those shown in the figure, and a configuration in which one of each is provided may also be used.

[0025] The control device C includes a memory for storing data and processing circuitry for computing data, including a processor, central processing unit, microprocessor, microcontroller, and / or hardware control logic.

[0026] When the substrate W is released from the electrostatic chuck E, a signal Si related to the attracted state of the substrate W is input to the control device C. The control device C refers to the data of the reference state stored in the control device C and determines whether the attracted state is the reference state. If the reference state is not satisfied, the control device C outputs a signal So for changing the release voltage.

[0027] More specifically, the signal Si is the load applied to the desorption device F, which will be described later. The control device C stores the load value when the substrate W can be desorption as a reference value. The control device C compares the load applied to the desorption device F with the reference value. If the load applied to the desorption device F is equal to or less than the reference value, that is, if the reference state is satisfied, the desorption operation of the substrate W by the desorption device F continues. Conversely, if the load exceeds the reference value, the control device C outputs a signal So to increase the set value of the desorption voltage.

[0028] The reference state is a state in which the substrate W is attracted and supported by the electrostatic chuck E to such an extent that various defects such as bouncing or cracking of the substrate W due to residual attracting force do not occur when the substrate W is released from the electrostatic chuck E. The value of the load applied to the release device F when the reference state is achieved is obtained in advance by experiment and stored in the control device C.

[0029] 4, 6 and 7 are explanatory diagrams of the substrate detachment operation, which is carried out in the order of FIG. 4, FIG. 6 and FIG. Fig. 5 is a plan view when viewed from the ZX plane in Fig. 4. When the vacuum hand V1 (V2) is viewed from above, the members drawn with dashed lines are hidden by the vacuum hand V1 (V2) and the substrate W. After the substrate processing, the platen 2 moves downward while maintaining a slightly inclined posture. After that, the vacuum hand V1 (V2) rotates to the position of the platen 2. This state is shown in Figures 4 and 5.

[0030] The vacuum hand V1 (V2) has a gripping portion C1 (C2) that extends downward. This gripping portion C1 (C2) is divided into two portions with a gap in the X-axis direction to accommodate the platen 2. By rotating the vacuum hand V1 (V2) to the position of the platen 2, the platen 2 is positioned between the gripping portions C1 (C2) of the vacuum hand V1 (V2). The gripping portion C1 (C2) has a claw portion N1 and a claw portion N2 between the opposing gripping portion C1 (C2). Since the lengths of the gripping portions C1 (C2) are different, the attachment positions of the claw portion N1 and the claw portion N2 in the Y-axis direction are different. Specifically, the claw portion N1 is provided at a slightly higher position than the claw portion N2.

[0031] The configuration of the removing device F is changed depending on the configuration for removing the substrate W. In the embodiment of FIGS. 4 to 7, a de-mounting device F that de-mounts the substrate W from the electrostatic chuck E includes a claw portion N1 and a driving source D2.

[0032] The platen 2 shown in FIG. 4 is rotated clockwise by the drive source D2, resulting in the state shown in FIG. 6. In FIG. 6, the claw portion N1 abuts against the edge of the substrate W. In this state, as the drive source D2 continues to rotate the platen 2, a load is applied to the drive source D2. Based on the measurement results of this load, the control device C determines the suction state of the substrate W. The torque is constant when the drive source D2 continues to rotate the platen 2.

[0033] The initial load when the claw portion N1 contacts the edge of the substrate W is relatively large. After a few seconds, the load applied to the drive source D2 converges to a substantially constant value. The control device C uses the value at which the load value converges to determine the suction state of the substrate W.

[0034] When the substrate W is physically released by the release device F, specifically, the edge of the substrate W is pressed against the claw portion N1, and then the control device C applies a release voltage to the electrostatic chuck E. The desorption voltage is a voltage that cancels out residual charge remaining between the substrate W and the electrostatic chuck E. For example, the desorption voltage may be a voltage of the same polarity as the clamping voltage applied to the electrostatic chuck during substrate processing, but approximately 30% of the magnitude of the clamping voltage. Alternatively, the desorption voltage may be a voltage of the opposite polarity to the clamping voltage applied to the electrostatic chuck during substrate processing, but smaller than the clamping voltage.

[0035] If no desorption voltage is applied, a large force is required to desorb the edge of the substrate W from the electrostatic chuck E. However, by applying the desorption voltage, the residual adsorptive force acting on the substrate W is reduced, and therefore the force required to desorb the edge of the substrate W from the electrostatic chuck E can be reduced. As a result, it is possible to reduce the risk of damage to the substrate edge when the substrate is desorbed.

[0036] After the substrate W is released from the electrostatic chuck E by the rotation of the platen 2, the platen 2 moves downward as shown in Fig. 7. By moving the platen 2 downward, the substrate W is placed on the claws N1 and N2.

[0037] Since a configuration is adopted in which the suction state of the substrate W is determined based on the load applied to the desorption device F, it is possible to accurately determine the suction state of the substrate W even if the substrate W is significantly warped due to high-temperature processing.

[0038] When the control device C determines that the current attraction state does not satisfy the reference state, it changes the de-sorption voltage applied to the electrostatic chuck E to a larger set value. The set value of the de-sorption voltage described here is an absolute value. By changing the set value of the desorption voltage, it is possible to actively reduce the residual charge and shorten the time required to desorb the substrate W.

[0039] The setting value of the desorption voltage may be set to a relatively large value from the initial stage, however, there is a concern that the application of a large desorption voltage may cause the residual charge to disappear in a very short time, and the substrate W may be attracted again to the electrostatic chuck E by the desorption voltage. For this reason, it is desirable to apply a small release voltage in the initial stage and then increase the release voltage setting stepwise to V1, V2, and V3 over time as shown in Figure 8. In this case, taking into consideration the possibility of re-attachment as mentioned above, the release voltage should not exceed the attraction voltage Vc during substrate processing.

[0040] When the de-chuck voltage is changed, the load on the de-chuck device F is continuously measured. This configuration makes it possible to de-chuck the substrate W from the electrostatic chuck E at an appropriate timing. The magnitude of the set value of the de-chuck voltage may be changed stepwise as shown in FIG. 8, or may be changed linearly or in a curve.

[0041] When changing the set value of the desorption voltage, it is not essential to desorb the substrate W from the electrostatic chuck E by the initial operation of pressing the edge of the substrate W against the claw portion N1. By changing the set value of the desorption voltage, the residual attracting force gradually decreases, and therefore the force pressing the edge of the substrate W against the claw portion N1 can be reduced. As a result, the risk of damage to the substrate W during the substrate desorption operation can be further reduced.

[0042] FIG. 9 is a flowchart showing the substrate removal method. After the substrate processing is completed, the platen 2 moves downward and the vacuum hand V1 (V2) rotates. Then, the platen 2 rotates clockwise and the edge of the substrate W is pressed against the claw portion N1 (process S1). The position of the substrate W at this time is defined as the first release position. With the rotational torque of the platen 2 kept constant and the edge of the substrate W pressed against the claws N1, a release voltage is applied to the electrostatic chuck E (step S2).

[0043] The load applied to the drive source D2 when the desorption voltage is applied is compared with a reference value R (process S3). If the load is equal to or less than the reference value R, it is determined that the chucking state satisfies the reference state, and the substrate W is desorbed from the electrostatic chuck E. Thereafter, the platen 2 is moved further downward, and the substrate W is placed on the claw portions N1 and N2 (process S4). The position of the substrate W at this time is set as the second desorption position. On the other hand, if the load exceeds the reference value R in process S3, it is determined that the attraction state does not satisfy the reference state, and the set value of the release voltage is increased (process S5). After resetting the release voltage, the load on the driving source D2 is measured, and the measured value is compared with the reference value R again (process S3). Finally, processes S5 and S3 are repeated until the conditions of process S3 are satisfied.

[0044] The measurement of the load applied to the driving source D2 may be carried out continuously while the substrate W moves from the first release position to the second release position. By continuously measuring the load applied to the driving source D2, it becomes possible to determine not only the suction state of the substrate W, but also whether the substrate W has been transported to the first release position or the second release position.

[0045] The substrate W may be released by a lift pin as in the prior art. In this case, a force sensor may be provided on the lift pin to measure the load on the lift pin, thereby determining the suction state of the substrate W. However, in this configuration, a force sensor must be provided separately, which incurs additional costs, and maintenance is required when the force sensor breaks down. Considering these points, it is desirable to measure the load applied to the drive source used for substrate transport using a drive source that is originally provided as part of the device configuration, and to determine the suction state of the substrate W.

[0046] In the above embodiment, the load applied to the driving source D2 is measured to determine the suction state of the substrate W. However, the present invention is not limited to this configuration, and the load applied to another driving source may be measured to determine the suction state of the substrate W. For example, the attracting state of the substrate W may be determined by measuring the load applied to the drive source D1 for moving the drive shaft 12 up and down. In this case, when the platen 2 is in the state shown in Fig. 4 or 6, the drive source D1 moves the drive shaft 12 downward to detach the substrate W from the electrostatic chuck E. At this time, the platen 2 is not rotated by the drive source D2.

[0047] In the above embodiment, the configuration of an ion implantation apparatus has been described as an example of the substrate processing apparatus WD, but the substrate processing apparatus WD of the present invention can also be applied to other semiconductor manufacturing apparatuses.

[0048] 10 illustrates an example of the configuration of a film formation apparatus. In a processing chamber 21, a substrate W is placed on a platen 22. The platen 22 is equipped with an electrostatic chuck E and a heater H. A ring clamp 23 presses the upper end of the substrate W toward the platen 22. A film formation process on the substrate W is performed by irradiating the substrate W with plasma from above.

[0049] The ring clamp 23 is connected to a drive shaft 25. The drive shaft 25 is moved up and down in the direction of the arrow in the figure by a drive source 26. An L-shaped lift pin 24 is connected to the drive shaft 25. In the figure, the ring clamp 23 and the lift pin 24 are drawn on the left and right, but these components are all connected to the drive shaft 25 and move up and down in conjunction with the up and down movement of the drive shaft 25.

[0050] After the substrate processing, the drive shaft 25 moves upward, thereby releasing the clamping of the substrate W by the ring clamp 23. As the drive shaft 25 continues to move upward, the tip ends of the lift pins 24 come into contact with the back surface of the substrate W, and a load is applied to the drive source 26. The load generated at this time is transmitted as a signal Si to the control device C. The control device C compares the load applied to the drive source 26 with a reference value stored in the control device C, as in the previous embodiment. If the comparison result indicates that the voltage exceeds the reference value, the control device C outputs a signal So to increase the set value of the break-off voltage.

[0051] If the comparison result by the control device C indicates that the load applied to the drive source 26 is equal to or less than the reference value, the lift pins 24 are moved upward to detach the substrate W from the electrostatic chuck E. Thereafter, the valve 27 is opened, and the hand of the transfer robot is introduced into the processing chamber 21 to retrieve the processed substrate W on the lift pins 24. In the film forming apparatus of FIG. 10, the detachment device F includes lift pins 24, a drive shaft 25, and a drive source .

[0052] In the above embodiment, the high-temperature processing that causes a large warp in the substrate W has been described as an example, but the configuration of the present invention may also be used for a substrate removal operation that is performed after substrate processing at room temperature. Furthermore, the means for determining the suction state may be switched depending on the temperature of the substrate processing. When the temperature of the substrate processing is high, the configuration of the present invention is used, in which the suction state of the substrate is determined based on the load of the desorption device F. When the temperature of the substrate processing is room temperature, the electrostatic capacitance is measured to determine the suction state of the substrate. If the substrate processing temperature is room temperature, the substrate W will not be significantly warped, and therefore the attracted state of the substrate can be accurately determined even by measuring the electrostatic capacitance.

[0053] Furthermore, the attracting state of the substrate may be determined first by measuring the electrostatic capacitance, and if the determination becomes impossible due to an abnormal measured value or if it is determined that the substrate is not attracted to the electrostatic chuck E, the attracting state of the substrate may be determined based on the load of the de-chuck F.

[0054] Furthermore, the present invention is not limited to the above-described embodiment, and it goes without saying that various modifications are possible without departing from the spirit of the present invention. [Explanation of symbols]

[0055] W substrate E Electrostatic Chuck F Release device C Control device WD Substrate Processing Equipment

Claims

1. an electrostatic chuck for adsorbing and supporting a substrate to be processed at high temperature; a de-chuck configured to de-chuck the substrate supported by the electrostatic chuck; a control device that applies a de-chuck voltage to the electrostatic chuck when the de-chuck device physically de-chucks the substrate, The control device determines the suction state of the substrate based on the load of the desorption device.

2. The substrate processing apparatus according to claim 1 , wherein the control device changes the take-off voltage to a larger voltage when the load is larger than a reference value.

3. The substrate processing apparatus according to claim 2 , wherein the control device continuously measures the load on the release device when the release voltage is changed.

4. 2. The substrate processing apparatus according to claim 1, wherein the control device applies, as the desorption voltage, a voltage that is smaller than a clamping voltage applied to the electrostatic chuck during processing of the substrate.

5. The substrate processing apparatus according to claim 1 , wherein the removing device includes a drive source used for transferring the substrate.

6. supporting the substrate to be subjected to high temperature processing by electrostatic chuck; physically removing the substrate from the electrostatic chuck after high temperature processing of the substrate; applying a desorption voltage to the electrostatic chuck when physically desorbing the substrate; determining an adsorption state of the substrate based on a load when physically removing the substrate.

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