Substrate processing apparatus and substrate processing method
Patent Information
- Authority / Receiving Office
- TW · TW
- Patent Type
- Patents
- Current Assignee / Owner
- ULVAC INC
- Filing Date
- 2024-02-15
- Publication Date
- 2026-08-01
Smart Images
Figure 00000000_0000_ABST
Abstract
Description
Substrate Processing Apparatus and Substrate Processing Method The present disclosure relates to a substrate processing apparatus and a substrate processing method. An example of a device for eliminating static electricity of an object to be statically eliminated located in a vacuum chamber includes: a vacuum chamber in which the object to be statically eliminated is disposed, and a ground electrode that closes an opening of the vacuum chamber. An insulating ring member is installed on the ground electrode, and a filament and a mesh electrode are installed on the ring member. The filament is installed on the ring member so as to protrude into a space surrounded by the ring member, and the mesh electrode is installed on the ring member so as to sandwich the space surrounded by the ring member together with the ground electrode. In the static elimination device, while a current is supplied to the filament and a voltage is applied to the mesh electrode, a gas is supplied into the space surrounded by the ring member, thereby generating plasma. Thereby, the charge of the object to be statically eliminated located in the vacuum chamber is statically eliminated (see, for example, Patent Document 1). [Prior Art Documents] [Patent Documents] [Patent Document 1] Japanese Patent Application Laid-Open No. 2021-157909 (Problems to be Solved by the Invention) However, a cluster tool type device, which is an example of a substrate processing device, includes: a transfer chamber, and a plurality of processing chambers connected to the transfer chamber through gate valves. If the processing chamber is, for example, a sputtering chamber, a target and a stage facing the target are located in the sputtering chamber, and an electrostatic chuck for adsorbing a substrate is located in the stage. The above-described static elimination device must be provided in a vacuum chamber in which the object to be statically eliminated is disposed. Therefore, if the object to be statically eliminated is a member located in the sputtering chamber, members for generating plasma, such as a filament or a mesh electrode, must be installed in the sputtering chamber. However, various members for performing sputtering film formation are installed in the sputtering chamber, so it is sometimes difficult to install the members for generating plasma in the sputtering chamber. Therefore, it is desired to generate plasma in a processing chamber different from the processing chamber in which the object to be statically eliminated is disposed and to perform static elimination by the plasma. Such a problem is not limited to a cluster tool type device having a sputtering chamber, and is common to a film forming device having a processing chamber for forming a film by a method other than a sputtering method such as a CVD method, or a processing device for performing processing other than film formation, and a device having two or more vacuum chambers. (Means for Solving the Problem) A substrate processing apparatus for solving the above problems includes: a first vacuum chamber that defines a first space for accommodating an object to be electrostatically eliminated; a second vacuum chamber that defines a second space; a connection part that connects the second vacuum chamber to the first vacuum chamber; and an electrostatic elimination part that electrostatically eliminates the object to be electrostatically eliminated located in the first vacuum chamber. The connection part has an opening that communicates the second space to the first space. A space including the first space and the second space that communicate with each other through the opening is a processing space. The electrostatic elimination part is configured to generate plasma from a plasma generation gas supplied into the second vacuum chamber, and electrostatically eliminate the object to be electrostatically eliminated located in the first space because the mean free path of charged particles in the plasma in the processing space is shorter than the minimum size of the opening in a plane orthogonal to the plane along the direction from the second space toward the first space. A substrate processing method for solving the above problems includes: communicating a second space defined by a second vacuum chamber to a first space defined by the first vacuum chamber and accommodating an object to be electrostatically eliminated through an opening of a connection part that connects the second vacuum chamber to the first vacuum chamber; and generating plasma including the charged particles from a plasma generation gas supplied into the second vacuum chamber in such a manner that the mean free path of the charged particles in a processing space including the first space and the second space that communicate with each other through the opening is shorter than the minimum size of the opening in a plane orthogonal to the plane along the direction from the second space toward the first space, thereby electrostatically eliminating the object to be electrostatically eliminated located in the first space. With the above substrate processing apparatus and substrate processing method, charged particles in the plasma easily move from the second space toward the first space. Therefore, the potential of the object to be electrostatically eliminated easily becomes smaller, and in addition, the time required for electrostatic elimination of the object to be electrostatically eliminated can be shortened. In the above substrate processing apparatus, the electrostatic elimination part may also adjust the mean free path in such a manner that the mean free path of the charged particles is shorter than the minimum size of the opening by the pressure in the processing space. With the above substrate processing apparatus, the mean free path of charged particles is inversely proportional to the pressure. Therefore, if the pressure in the processing space is adjusted, the mean free path of charged particles can be easily changed. In the above substrate processing apparatus, the electrostatic elimination part may also adjust the pressure in the processing space by the flow rate of the plasma generation gas supplied into the processing space. With the above substrate processing apparatus, since the mean free path of charged particles generated in the processing space can be changed only by changing the flow rate of the plasma generation gas supplied into the processing space, the mean free path can be easily adjusted. In the above-described substrate processing apparatus, the gas for plasma generation may also be a noble gas. With the above-described substrate processing apparatus, in the plasma generated from the noble gas, the diameter of the charged particles is likely to be larger than the diameter of the charged particles included in the plasma generated using other inert gases. Therefore, it is easy for the mean free path to be shorter than the size of the opening. Referring to FIGS. 1 to 10, an embodiment of a substrate processing apparatus and a substrate processing method will be described. [Substrate Processing Apparatus] Referring to FIGS. 1 to 3, a substrate processing apparatus will be described. Hereinafter, a cluster tool type sputtering apparatus as an example of a substrate processing apparatus will be described. As shown in FIG. 1, the cluster tool type sputtering apparatus 10 includes a transfer chamber 11, two sputtering chambers 12, a loading / unloading chamber 13, and two substrate processing chambers 14. The sputtering apparatus 10 includes a first sputtering chamber 12A and a second sputtering chamber 12B as the two sputtering chambers 12. Each of the processing chambers 12A, 12B, 13, and 14 is connected to the transfer chamber 11. Gate valves are located between the transfer chamber 11 and each of the processing chambers 12A, 12B, 13, and 14. When the gate valves are opened, the transfer space defined by the transfer chamber 11 communicates with the processing spaces defined by each of the processing chambers 12A, 12B, 13, and 14. In contrast, when the gate valves are closed, the transfer space of the transfer chamber 11 and the processing spaces of each of the processing chambers 12A, 12B, 13, and 14 are separated from each other. The transfer chamber 11 includes a transfer robot 11R. The transfer robot 11R is configured to be able to transfer a substrate between each of the processing chambers connected to the transfer chamber 11 and the transfer chamber 11. The transfer robot 11R transfers the substrate along a plane substantially parallel to the horizontal plane between the transfer chamber 11 and each of the processing chambers. The transfer chamber 11 includes a plasma generation unit 11P that generates plasma in the transfer space. The plasma generation unit 11P can be located at the center of the transfer chamber 11 when the transfer chamber 11 is viewed from above, for example. The loading / unloading chamber 13 is configured to be able to load a substrate before processing into the sputtering apparatus 10 from outside the sputtering apparatus 10 and unload the substrate after processing from inside the sputtering apparatus 10 to outside the sputtering apparatus 10. The loading / unloading chamber 13 includes an exhaust unit 13E. When a substrate is loaded, with the loading / unloading chamber 13 separated from the transfer chamber 11, the loading / unloading port of the loading / unloading chamber 13 is opened, whereby the loading / unloading chamber 13 is opened to the atmosphere. Then, after the substrate before processing is loaded through the loading / unloading port, the loading / unloading port is closed. Then, the inside of the loading / unloading chamber 13 is exhausted by the exhaust unit 13E, whereby the inside of the loading / unloading chamber 13 is depressurized to the same level as the transfer chamber 11. After that, the gate valve located between the loading / unloading chamber 13 and the transfer chamber 11 is opened. In contrast, when the substrate is carried out, after the processed substrate is carried into the carry-in / carry-out chamber 13 from the transfer chamber 11, the gate valve located between the carry-in / carry-out chamber 13 and the transfer chamber 11 is closed. Next, after the pressure in the carry-in / carry-out chamber 13 is increased to atmospheric pressure, the carry-in / carry-out opening of the carry-in / carry-out chamber 13 is opened. Then, the processed substrate is carried out from the carry-in / carry-out opening to the outside of the sputtering apparatus 10. Each of the sputtering chambers 12A and 12B is provided with a cathode 20. Each of the sputtering chambers 12A and 12B is configured to form a thin film on the surface of the substrate by sputtering using the cathode 20. Each of the sputtering chambers 12A and 12B is provided with exhaust portions 12AE and 12BE for exhausting the processing space defined by the sputtering chambers 12A and 12B. Each substrate processing chamber 14 is configured to perform a predetermined process on the substrate. The process performed in the substrate processing chamber 14 can be a pre-process performed on the substrate before film formation in the sputtering chambers 12A and 12B, or a post-process performed on the substrate after film formation in the sputtering chambers 12A and 12B. The pre-process and the post-process can be, for example, heat treatment or cooling treatment. Each substrate processing chamber 14 is provided with an exhaust portion 14E for exhausting the processing space defined by the substrate processing chamber 14. Referring to FIG. 2, the transfer chamber 11 and the first sputtering chamber 12A will be described in more detail. Among them, in FIG. 2, for convenience of illustration, the distance between the plasma generation unit 11P and the first sputtering chamber 12A is shorter than the distance between the plasma generation unit 11P and the first sputtering chamber 12A in FIG. 1. As shown in FIG. 2, the transfer chamber 11 defines a transfer space 11S for transferring the substrate Sb. The first sputtering chamber 12A defines a first film formation space 12AS. The sputtering apparatus 10 is provided with a connection portion 10P that connects the transfer chamber 11 to the first sputtering chamber 12A. The connection portion 10P has an opening 10PA (refer to FIG. 3) that communicates the transfer space 11S of the transfer chamber 11 to the first film formation space 12AS of the first sputtering chamber 12A. The gate valve 10G is located at the connection portion 10P. Since the gate valve 10G is opened and the opening 10PA is opened, the first film formation space 12AS communicates with the transfer space 11S through the opening 10PA. In contrast, since the gate valve 10G is closed and the opening 10PA is blocked, the first film formation space 12AS is separated from the transfer space 11S. The space defined by the connection portion 10P that connects the transfer space 11S and the first film formation space 12AS that communicate with each other through the opening 10PA is included in the processing space together with the transfer space 11S and the first film formation space 12AS. The transfer chamber 11 includes a vacuum chamber 11C that defines a transfer space 11S. The vacuum chamber 11C is an example of a second vacuum chamber, and the transfer space 11S is an example of a second space. The transfer chamber 11 is provided with a plasma generation unit 11P as described above. The plasma generation unit 11P generates plasma from a plasma generation gas supplied into the transfer space 11S. The plasma generation unit 11P is, for example, a microwave plasma source. The first sputtering chamber 12A includes a vacuum chamber 12AC that defines a first film formation space 12AS. The vacuum chamber 12AC is an example of a first vacuum chamber, and the first film formation space 12AS is an example of a first space for accommodating an object to be electrostatically eliminated. The first sputtering chamber 12A is provided with a cathode 20 as described above. The cathode 20 includes a target 21 and a backing plate 22. The target 21 is formed of, for example, a metal, a metal compound, or a mixture of a metal and a metal compound. The target 21 has a sputtered surface that is sputtered when forming a film on the substrate Sb. The backing plate 22 is joined to the target 21. The backing plate 22 has conductivity. The cathode 20 is mounted on one surface of the side wall portion that defines the first film formation space 12AS. At least the sputtered surface of the target 21 in the cathode 20 is exposed to the first film formation space 12AS. A target power source 23 is connected to the backing plate 22. A voltage is applied to the backing plate 22 by the target power source 23, and a voltage is applied to the target 21 connected to the backing plate 22. The target power source 23 can be, for example, a DC power source or an AC power source. The first sputtering chamber 12A includes a support portion 31 and an adsorption portion 32. The support portion 31 is an example of an object to be electrostatically eliminated. The support portion 31 has a support surface 31F for supporting the substrate Sb. The support surface 31F can be formed of, for example, a material different from the material of the surface of the substrate Sb that contacts the support surface 31F. For example, the support surface 31F can be formed of alumina, and the substrate Sb is a glass substrate. For example, the support portion 31 has a flat plate shape, and the support surface 31F is one plane provided by the support portion 31. The adsorption portion 32 is located inside the support portion 31. The adsorption portion 32 electrostatically adsorbs the substrate Sb located on the support surface 31F to the support surface 31F. The adsorption portion 32 is an electrostatic chuck that uses electrostatic force to adsorb the substrate Sb. The first sputtering chamber 12A is provided with a position changing unit 33. The position changing unit 33 is configured to be able to change the position of the support unit 31 relative to the cathode 20. The position changing unit 33 changes the position of the support unit 31 between a first position and a second position. When the support unit 31 is located at the first position, the support surface 31F is substantially orthogonal to the cathode 20. That is, when the support unit 31 is located at the first position, the support surface 31F is positioned along a substantially horizontal direction. In contrast, when the support unit 31 is located at the second position, the support surface 31F is substantially parallel to the cathode 20. That is, when the support unit 31 is located at the second position, the support surface 31F is positioned along a substantially vertical direction. The first sputtering chamber 12A is further provided with a gas introduction unit 34. The gas introduction unit 34 is a gas inlet of the vacuum chamber 12AC. The gas introduction unit 34 is connected to a gas cylinder located outside the sputtering device 10 through a mass flow controller. The gas introduction unit 34 introduces a plasma generation gas into the first film formation space 12AS. The plasma generation gas is, for example, an inert gas. The inert gas can also be a noble gas or nitrogen. The noble gas can also be, for example, argon or helium. A plasma containing charged particles is generated from the plasma generation gas. In the present disclosure, charged particles refer to particles having a charge other than electrons. For example, if argon is the plasma generation gas, positively charged argon ions are an example of charged particles. If helium is the plasma generation gas, positively charged helium ions are an example of charged particles. The gas introduction unit 34 may also be provided with: a conduction valve. The conduction valve sets the flow rate of the gas flowing into the first film formation space 12AS through the gas introduction unit 34 by the opening degree. By changing the opening degree of the conduction valve from a first opening degree to a second opening degree, the flow rate of the gas flowing into the first film formation space 12AS is changed from a first flow rate to a second flow rate. When the support unit 31 is located at the second position, whereby the support surface 31F is positioned along a substantially vertical direction, when viewed from an angle facing the horizontal plane, the gas introduction unit 34 can be located, for example, between the support unit 31 and the target 21. The gas introduction unit 34 can be located, for example, on the upper wall portion of the vacuum chamber 12AC. At this time, the gas introduction unit 34 introduces gas into the first film formation space 12AS along a direction from above to below in the vertical direction. The vacuum chamber 12AC is further provided with: an exhaust port 35 connected to the exhaust unit 12AE. The first sputtering chamber 12A may also be provided with a conduction valve between the exhaust port 35 and the exhaust unit 12AE. The conduction valve sets the exhaust flow rate by the opening degree. By changing the opening degree of the conduction valve from a first opening degree to a second opening degree, the exhaust flow rate is changed from a first flow rate to a second flow rate. When forming a film on the substrate Sb, the pressure in the first film-forming space 12AS is adjusted to a predetermined pressure by exhausting using the exhaust section 12AE and the plasma generation gas introduced from the gas introduction section 34. The pressure in the first film-forming space 12AS can be, for example, 1×10 -1 Pa or more and 1×10 1 Pa or less. The pressure in the first film-forming space 12AS during film formation can also be the same as the pressure in the first film-forming space 12AS during static elimination in the first sputtering chamber 12A. When performing static elimination of the support section 31, the pressure in the first film-forming space 12AS is adjusted to a predetermined pressure by exhausting using the exhaust section 12AE and the plasma generation gas introduced from the gas introduction section 34. When performing static elimination of the support section 31, since the gate valve 10G is opened and the opening 10PA is opened, the pressure in the first film-forming space 12AS is approximately equal to the pressure in the transfer space 11S. Therefore, the pressure in the processing space including the first film-forming space 12AS and the transfer space 11S is substantially uniform. Therefore, the mean free path of the charged particles in the first film-forming space 12AS can be regarded as equal to the mean free path of the charged particles in the transfer space 11S, and also equal to the mean free path of the charged particles in the processing space. When performing static elimination of the support section 31, the pressure in the first film-forming space 12AS can be, for example, 1×10 -1 Pa or more and 1×10 1 Pa or less. Figure 3 shows the planar structure of the opening 10PA of the connection section 10P. Figure 3 shows the structure of the opening 10PA in a plane orthogonal to the plane along the direction from the transfer chamber 11 to the first sputtering chamber 12A. That is, Figure 3 shows the structure of the opening 10PA in a plane orthogonal to the plane along the direction in which the connection section 10P connecting the transfer chamber 11 to the first sputtering chamber 12A extends. Among them, the connection section 10P shown in Figures 1 and 2 has a cylindrical shape extending along the direction from the transfer chamber 11 to the first sputtering chamber 12A, so the inner surface of the connection section 10P defines the passage of the transfer robot 11R on which the substrate Sb is placed. The plate member 10PB shown in Figure 3 is located in the passage defined by the connection section 10P. The plate member 10PB has an opening 10PA. The outer edge of the plate member 10PB is in contact with the inner surface of the connection section 10P, whereby, in the plane including the plate member 10PB, in the passage defined by the connection section 10P, the portion other than the opening 10PA is sealed. Therefore, the transfer space 11S communicates with the first film-forming space 12AS through the opening 10PA. In this embodiment, the opening 10PA has a rectangular shape. In the example shown in FIG. 3, the four corners of the opening 10PA have a curvature with the center of curvature located within the opening 10PA. Since the opening 10PA has a rectangular shape, among the opening 10PA, the length of the short side 10PAS corresponds to the minimum size Lm of the opening 10PA. The opening 10PA is not limited to a rectangular shape and may have, for example, a polygonal shape other than a rectangular shape. The polygonal shape other than a rectangular shape includes, for example, a square shape, a diamond shape, and a hexagonal shape. The opening 10PA may also have a circular shape. Here, the minimum size of the opening 10PA means the geometric center of the outer edge of the opening 10PA and the length of the line segment connecting the first point and the second point on the outer edge. Therefore, for example, if the opening 10PA has a square shape, the length of the line segment passing through the geometric center of the outer edge of the opening 10PA and connecting a pair of parallel sides on the outer edge is the minimum size of the opening 10PA. Further, if the opening 10PA has a circular shape, the line segment passing through the geometric center of the outer edge of the opening 10PA and connecting two points on the circumference, that is, the diameter of the circle, is the minimum size of the opening 10PA. In the sputtering apparatus 10 of this embodiment, the static eliminator generates plasma from the plasma generation gas supplied into the transfer chamber 11. At this time, it is configured such that the mean free path of the charged particles in the processing space is shorter than the minimum size Lm of the opening 10PA, and the support portion 31 located in the first film formation space 12AS is electrostatically eliminated. Thereby, the charged particles in the plasma easily move from the transfer space 11S toward the first film formation space 12AS. Therefore, the potential of the support portion 31, that is, the absolute value in the potential of the support portion 31 easily becomes smaller, and further, the time required for electrostatic elimination of the support portion 31 can be shortened. That is, the support portion 31 is easily electrostatically eliminated. The mean free path λ of the charged particles is calculated by the following formula (1). [Equation 1] Formula (1) In formula (1), 2r is the diameter of the charged particle, and n is the particle number density. Therefore, the mean free path is inversely proportional to the pressure according to the following formula (2). [Equation 2] Formula (2) In formula (2), p is the pressure, n is the particle number density, k is the Boltzmann constant, and T is the thermodynamic temperature. The static eliminator can adjust the mean free path by the pressure in the processing space so that the mean free path of the charged particles is shorter than the minimum size Lm of the opening 10PA. From the above formulas (1) and (2), it can be seen that the mean free path of the charged particles is inversely proportional to the pressure. Therefore, if the pressure in the processing space is adjusted, the mean free path of the charged particles can be easily changed. The static electricity eliminating unit can also adjust the pressure in the processing space by the flow rate of the plasma generating gas supplied into the processing space. At this time, the mean free path of the charged particles generated in the processing space can be changed only by changing the flow rate of the plasma generating gas supplied into the processing space, so it is easy to adjust the mean free path. The plasma generating gas can be a noble gas. In the plasma generated by the noble gas, the diameter of the charged particles is likely to be larger than that of the charged particles included in the plasma generated using other inert gases. Therefore, it is easy to make the mean free path shorter than the size of the opening 10PA. [Substrate processing method] The substrate processing method of the present embodiment includes: connecting the first film forming space 12AS to the transfer space 11S, and eliminating static electricity of the support portion 31 located in the first film forming space 12AS. In connecting the first film forming space 12AS to the transfer space 11S, the transfer space 11S is connected to the first film forming space 12AS through the opening 10PA of the connection portion 10P. In eliminating static electricity of the support portion 31, plasma is generated from the plasma generating gas supplied into the transfer chamber 11 in such a manner that the mean free path of the charged particles in the plasma in the processing space is shorter than the minimum size of the opening 10PA, thereby eliminating static electricity of the support portion 31. The substrate processing method in the present embodiment will be described in more detail below. When eliminating static electricity of the support portion 31, with the exhaust portion 12AE provided in the first sputtering chamber 12A reducing the pressure in the first film forming space 12AS to a predetermined pressure, the gate valve 10G is opened. Thereby, since the opening 10PA is opened, the transfer space 11S defined by the transfer chamber 11 is also reduced in pressure together with the first film forming space 12AS by the exhaust portion 12AE. After a predetermined period has elapsed after the gate valve 10G is opened, the plasma generating gas is introduced into the first film forming space 12AS by the gas introduction portion 34. The timing of starting to introduce the plasma generating gas into the first film forming space 12AS is preferably set after the period in which the transfer space 11S is reduced in pressure to the same level as the first film forming space 12AS has elapsed. By introducing the plasma generating gas into the first film forming space 12AS, the plasma generating gas is also introduced into the transfer space 11S through the opening 10PA. After a predetermined period has elapsed since the start of introducing the plasma-generating gas, microwave power is supplied to the plasma generation unit 11P, thereby generating plasma from the plasma-generating gas in the transfer space 11S. The charged particles in the plasma are supplied from the transfer space 11S to the first film formation space 12AS through the opening 10PA, whereby the support unit 31 to be the object of static elimination is statically eliminated. That is, in the sputtering apparatus 10 of the present embodiment, the static elimination unit that statically eliminates the support unit 31 located in the first film formation space 12AS includes: a gas introduction unit 34, an exhaust unit 12AE, and a plasma generation unit 11P. The static elimination of the support unit 31 is performed during a period when the substrate Sb is not electrostatically adsorbed to the support unit 31. Therefore, the static elimination of the support unit 31 is performed between the film formation process for the first substrate Sb and the film formation process for the second substrate Sb. Among them, the static elimination of the support unit 31 can be performed every time the film formation process for the substrate Sb is performed, or can be performed every time the film formation process for a plurality of substrates Sb is performed. [Test Example] Referring to FIGS. 4 to 10, the test examples will be described. FIG. 4 is a plan view showing the positions of the charged plates arranged on the support unit 31. As shown in FIG. 4, in Test Examples 1 to 3, charged plates are arranged one by one at the four corners of the support unit 31 having a quadrangular shape. In the direction from the transfer chamber 11 toward the first sputtering chamber 12A, among the four corners of the support unit 31, in the corner portion having a shorter distance from the transfer chamber 11, the third plate P3 is arranged at the first corner portion, and the fourth plate P4 is arranged at the second corner portion. In addition, in the direction from the transfer chamber 11 toward the first sputtering chamber 12A, among the four corners of the support unit 31, in the corner portion having a longer distance from the transfer chamber 11, the first plate P1 is arranged at the first corner portion, and the second plate P2 is arranged at the second corner portion. Therefore, the distances from the plasma generation unit 11P to the respective charged plates are substantially equal between the first plate P1 and the second plate P2, and are also substantially equal between the third plate P3 and the fourth plate P4. The distance between the plasma generation unit 11P and the first plate P1 is 3750 mm, and the distance between the plasma generation unit 11P and the second plate P2 is 3820 mm. The distance between the plasma generation unit 11P and the third plate P3 is 2850 mm, and the distance between the plasma generation unit 11P and the fourth plate P4 is 2940 mm. [Test Example 1] In the cluster tool type sputtering apparatus 10, plasma is generated in the processing space in a state where the opening 10PA is open. The conditions for plasma generation are set as follows. ・ Pressure in the processing space: 6.8×10 -2Pa - Gas for plasma generation: Argon - Flow rate of gas for plasma generation: 11.12 sccm - Mean free path: 105 mm - Minimum size of opening 10 PA: 250 mm [Test Example 2] In Test Example 2, among the conditions during plasma generation in Test Example 1, the pressure inside the processing space and the mean free path were changed as shown below, and the flow rate of the gas for plasma generation was set as shown below. At this time, the opening degree of the conduction valve between the exhaust port and the exhaust section was changed from the opening degree in Test Example 1. Other than this, plasma was generated under the same conditions as in Test Example 1. ・ Pressure inside the processing space: 1.1×10 -2 Pa - Gas for plasma generation: 11.12 sccm - Mean free path: 650 mm [Test Example 3] In Test Example 3, among the conditions during plasma generation in Test Example 1, the pressure inside the processing space and the mean free path were changed as shown below, and the flow rate of the gas for plasma generation was set as shown below. At this time, the opening degree of the conduction valve between the exhaust port and the exhaust section was changed from the opening degree in Test Example 1. Other than this, plasma was generated under the same conditions as in Test Example 1. ・ Pressure inside the processing space: 6.1×10 -3 Pa - Gas for plasma generation: 11.12 sccm - Mean free path: 1170 mm [Evaluation Method and Evaluation Results] In each test example, after generating plasma inside the processing space with the initial voltage value of each charged plate set to approximately +1.2 V, the time-dependent change in the voltage value of each charged plate from the start of plasma generation was measured. In addition, after generating plasma inside the processing space with the initial voltage value of each charged plate set to approximately -1.2 V, the time-dependent change in the voltage value of each charged plate from the start of plasma generation was measured. The time-dependent change in the voltage value when the initial voltage value of the first plate P1 was set to approximately +1.2 V is as shown in Figure 5. In addition, the time-dependent change in the voltage value when the initial voltage value of the first plate P1 was set to approximately -1.2 V is as shown in Figure 6. The time-dependent change in the voltage value when the initial voltage value of the fourth plate P4 was set to approximately +1.2 V is as shown in Figure 7. In addition, the time-dependent change in the voltage value when the initial voltage value of the fourth plate P4 was set to approximately -1.2 V is as shown in Figure 8. As shown in FIGS. 5 and 6, regardless of the positive or negative of the initial voltage value in the first plate P1, in Test Example 1, it was found that if plasma generation was started, the voltage value of the first plate P1 rapidly approached 0 V during the period when the elapsed time from the start was less than 1 second. In contrast, regardless of the positive or negative of the initial voltage value in the first plate P1, in Test Examples 2 and 3, it was found that the change rate of the voltage value in the first plate P1 was relatively low. In addition, in Test Examples 2 and 3, it was found that at the point in time when about 30 seconds had elapsed from the start of plasma generation, the change in the voltage value of the first plate P1 stopped while the voltage value of the first plate P1 had not reached 0 V. In Test Examples 2 and 3, it was found that if the initial voltage value in the first plate P1 was negative, the change in the voltage value of the first plate P1 stopped in a state where the deviation of the voltage value of the first plate P1 from 0 V was large. As shown in FIGS. 7 and 8, regardless of the positive or negative of the initial voltage value in the fourth plate P4, in Test Example 1, it was found that if plasma generation was started, the voltage value of the first plate P1 rapidly approached 0 V during the period when the elapsed time from the start was about 1 second. However, it was found that the deviation of the voltage value in the fourth plate P4 from 0 V was larger than the deviation of the voltage value in the first plate P1 from 0 V. In contrast, regardless of the positive or negative of the initial voltage value in the fourth plate P4, in Test Examples 2 and 3, it was found that the change rate of the voltage value in the fourth plate P4 was relatively low. In addition, in Test Examples 2 and 3, it was found that if the initial voltage value of the fourth plate P4 was negative, at the point in time when about 20 seconds had elapsed from the start of plasma generation, the change in the voltage value of the fourth plate P4 stopped. At this time, it was found that the voltage value of the fourth plate P4 had not reached 0 V. In addition, in Test Examples 2 and 3, it was found that the change in the voltage value of the fourth plate P4 stopped in a state where the deviation of the voltage value of the fourth plate P4 from 0 V was large. As described above, it was found that when the mean free path of the charged particles is longer than the minimum size of the opening 10 PA, especially when the initial voltage value of the charged plate is negative, it is difficult to eliminate the static electricity of the charged plate. In contrast, if the mean free path of the charged particles is shorter than the minimum size of the opening 10 PA, the static electricity is eliminated equally regardless of the positive or negative of the initial voltage value of the charged plate. Therefore, it can be said that the difference between the mobility of electrons and the mobility of ions is suppressed. In addition, the effect caused by the mean free path of the charged particles being smaller than the minimum size of the opening 10 PA is more obvious when the initial voltage value of the charged plate is negative, that is, it is more obvious in the static electricity elimination by ions. Among them, the time-dependent change of the voltage value of the second plate P2 was found to have the same tendency as the time-dependent change of the voltage value of the first plate P1. In addition, the time-dependent change of the voltage value of the third plate P3 was found to have the same tendency as the time-dependent change of the voltage value of the fourth plate P4. Referring to FIGS. 9 and 10, the operation of the substrate processing apparatus will be described. FIG. 9 shows the behavior of charged particles when the mean free path of the charged particles is longer than the minimum size Lm of the opening 10PA. In contrast, FIG. 10 shows the behavior of charged particles when the mean free path of the charged particles is shorter than the minimum size Lm of the opening 10PA. As shown in FIG. 9, if the mean free path of the charged particles CP is equal to or greater than the minimum size Lm of the opening 10PA, before and after the charged particles CP pass through the opening 10PA, the charged particles CP are less likely to collide with other particles present in the processing space. Thereby, since the trajectory of the charged particles CP is less likely to change, it can be said that the charged particles CP are less likely to reach the support portion 31. In contrast, as shown in FIG. 10, if the mean free path of the charged particles CP is shorter than the minimum size Lm of the opening 10PA, before and after the charged particles CP pass through the opening 10PA, the charged particles CP are likely to collide with other particles present in the processing space. Thereby, since the trajectory of the charged particles CP is likely to change, it can be said that the proportion of the charged particles CP that reach the support portion 31 among the charged particles CP is likely to increase. As described above, by an embodiment of the substrate processing apparatus and the substrate processing method, the following effects can be obtained. (1) Since the charged particles CP in the plasma are likely to move from the transfer space 11S toward the first film formation space 12AS, the potential of the support portion 31 is likely to become smaller, and in addition, the time required for static elimination of the support portion 31 can be shortened. (2) The mean free path of the charged particles CP is inversely proportional to the pressure. Therefore, if the pressure in the processing space is adjusted, the mean free path of the charged particles CP can be easily changed. (3) Since the mean free path of the charged particles generated in the processing space can be changed only by changing the flow rate of the plasma generation gas supplied to the processing space, the mean free path can be easily adjusted. (4) In the plasma generated by the noble gas, the diameter of the charged particles is likely to be larger than the diameter of the charged particles included in the plasma generated using other inert gases. Therefore, it is easy to make the mean free path shorter than the size of the opening 10PA. Among them, the above-described embodiments can be implemented with the following modifications. [Electrostatic elimination unit] - The mean free path of the charged particles can also be changed from the first value to the second value by changing at least one of the flow rate of the plasma-generating gas, the type of the plasma-generating gas, the opening degree of the conduction valve between the exhaust port 35 and the exhaust unit 12AE, and the exhaust flow rate of the exhaust unit 12AE. That is, the mean free path of the charged particles can also be adjusted by any one of the flow rate of the plasma-generating gas, the type of the plasma-generating gas, the opening degree of the conduction valve between the exhaust port 35 and the exhaust unit 12AE, and the exhaust flow rate of the exhaust unit 12AE, or can be adjusted by any two or more of them. [Sputtering device] - The sputtering device can also be configured to include a plurality of processing chambers arranged along one direction, and the substrate to be processed is transported in the sputtering device along a plane substantially parallel to the vertical plane. In this case, the electrostatic elimination plasma can also be generated in such a manner that the mean free path of the charged particles is shorter than the minimum size of the opening between the second vacuum chamber and the first vacuum chamber where the electrostatic elimination plasma is generated, thereby obtaining the effect according to the above (1). [Substrate processing device] - The substrate processing device of the present disclosure can also be a film-forming device other than a sputtering device. The substrate processing device can be, for example, a CVD device. Alternatively, the substrate processing device of the present disclosure can also be a substrate processing device that performs processing other than film formation on the substrate. The substrate processing device can be, for example, an etching device. 10: Sputtering device 10G: Gate valve 10P: Connection part 10PA: Opening 10PAS: Short side 10PB: Plate member 11: Transfer chamber 11C: Vacuum chamber 11P: Plasma generation part 11R: Transfer robot 11S: Transfer space 12: Sputtering chamber 12A: First sputtering chamber, processing chamber 12AC: Vacuum chamber 12AE, 12BE: Exhaust part 12AS: First film-forming space 12B: Second sputtering chamber, processing chamber 13: Loading / unloading chamber, processing chamber 13E: Exhaust part 14: Substrate processing chamber, processing chamber 14E: Exhaust part 20: Cathode 21: Target 22: Backing plate 23: Target power supply 31: Support part 31F: Support surface 32: Adsorption part 33: Position changing part 34: Gas introduction part 35: Exhaust port CP: Charged particle Lm: Minimum size P1: First plate P2: Second plate P3: Third plate P4: Fourth plate Sb: Substrate [Fig. 1] is a block diagram schematically showing the structure of a cluster tool type sputtering apparatus as an example of a substrate processing apparatus. [Fig. 2] is a block diagram schematically showing the structure of the transfer chamber and the first sputtering chamber included in the sputtering apparatus shown in Fig. 1. [Fig. 3] is a plan view showing the opening included in the connection portion. [Fig. 4] is a plan view showing the position of the charged plate to be electrostatically eliminated. [Fig. 5] is a graph showing the relationship between the voltage value of the positively charged plate and the elapsed time from the start of the electrostatic elimination process. [Fig. 6] is a graph showing the relationship between the voltage value of the negatively charged plate and the elapsed time from the start of the electrostatic elimination process. [Fig. 7] is a graph showing the relationship between the voltage value of the positively charged plate and the elapsed time from the start of the electrostatic elimination process. [Fig. 8] is a graph showing the relationship between the voltage value of the negatively charged plate and the elapsed time from the start of the electrostatic elimination process. [Fig. 9] is an operation diagram for explaining the operation of the substrate processing apparatus. [Fig. 10] is an operation diagram for explaining the operation of the substrate processing apparatus. 10G: Gate valve 10P: Connection portion 11: Transfer chamber 11C: Vacuum chamber 11P: Plasma generation unit 11S: Transfer space 12A: First sputtering chamber 12AC: Vacuum chamber 12AE: Exhaust portion 12AS: First film formation space 20: Cathode 21: Target 22: Backing plate 23: Target power supply 31: Support portion 31F: Support surface 32: Adsorption portion 33: Position changing portion 34: Gas introduction portion 35: Exhaust port Sb: Substrate
Claims
1. A substrate processing apparatus comprising: a first vacuum chamber defining a first space for accommodating an object to be statically eliminated; a second vacuum chamber defining a second space; a connecting portion connecting the second vacuum chamber to the first vacuum chamber; and a static elimination unit for statically eliminating the object to be statically eliminated located in the first vacuum chamber, wherein the connecting portion has an opening connecting the second space to the first space, and the space including the first space and the second space connected to each other through the opening is a processing space, and the static elimination unit is configured to generate plasma by plasma generation gas supplied to the second vacuum chamber, and statically eliminate the object to be statically eliminated located in the first space by means that the mean free path of charged particles in the plasma in the processing space is shorter than the minimum size of the opening in a plane orthogonal to a plane along a direction from the second space toward the first space.
2. The substrate processing apparatus as described in claim 1, wherein, The aforementioned static electricity elimination section adjusts the mean free path of the aforementioned charged particles by using the pressure within the aforementioned processing space, such that the mean free path of the aforementioned charged particles is shorter than the aforementioned minimum size of the aforementioned opening.
3. The substrate processing apparatus as described in claim 2, wherein, The aforementioned static electricity elimination unit adjusts the pressure within the aforementioned processing space by adjusting the flow rate of the aforementioned plasma generating gas supplied to the aforementioned processing space.
4. The substrate processing apparatus as described in any one of claims 1 to 3, wherein, The aforementioned plasma generation gas is a rare gas.
5. A substrate processing method comprising: connecting a second space defined by a second vacuum tank to a first space defined by a first vacuum tank and containing an object to be statically eliminated by an opening in a connection portion of the second vacuum tank to a first vacuum tank; and generating a plasma containing the charge particles by means of a mean free path of charge particles in a processing space including the first space and the second space connected by the opening, such that the minimum size of the opening in a plane orthogonal to a plane along a direction from the second space toward the first space is shorter than the minimum size of the opening in the first space.