JP2006339529A - Plasma treatment chamber, electrical potential control device, electrical potential control method, program and storage medium - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a plasma treatment chamber in which the amount of attached polymer is easily controlled with a simple constitution. <P>SOLUTION: The plasma treatment chamber 10 has a cylindrical side wall member 45 covering an inner peripheral surface of a vessel 11. An electrical potential control device 46 is provided with a grounded conducting member 47 which moves up and down in contact to or in noncontact to the side wall member 45. In an RIE process, by moving the conducting member 47 down to bring into contact to the side wall member 45, an electric potential of the side wall member 45 is set at a ground potential. In an ashing process, by moving the conducting member 47 up to leave the wide wall member 45, the electric potential of the side wall member 45 is set at a floating potential. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a plasma processing chamber, a potential control device, a potential control method, a program, and a storage medium, and more particularly to a plasma processing chamber having components exposed to plasma.

  Conventionally, there has been known a plasma processing chamber including a cylindrical container and an electrode disposed in the container and connected to a high-frequency power source. In this plasma processing chamber, processing gas is introduced into the container, and the electrode applies high-frequency power to the space in the container. Further, when a semiconductor wafer as a substrate is accommodated in a container, the introduced processing gas is converted into plasma by high frequency power to generate ions and the like, and the semiconductor wafer is subjected to plasma processing, for example, etching processing by the ions and the like. .

In the above-described plasma processing chamber, when a reactive gas, for example, a mixed gas of C ₄ F ₈ gas and argon (Ar) gas is used as a processing gas, neutral active species (radicals) generated from the reactive gas are used. ) Adheres as a polymer to the inner side wall of the container (hereinafter simply referred to as “side wall”). If the amount of polymer attached is too large, when the plasma treatment is performed on the semiconductor wafer, the polymer may peel from the side wall and adhere to the surface of the semiconductor wafer as a deposit, so it is necessary to remove the polymer attached to the side wall. There is.

  The polymer adhering to the side wall is preferably removed by colliding the cations generated when the processing gas becomes plasma with the side wall, and the number of cations colliding with the side wall depends on the potential of the side wall. The Specifically, when the potential of the side wall is low and the potential difference between the side wall and the space where the processing gas becomes plasma is large, the number of cations colliding with the side wall increases, and the amount of polymer attached decreases.

  However, since the potential of the side wall is determined by the anode / cathode ratio that depends on the shape of the electrode and the side wall and the magnitude of the high-frequency power that is set to obtain a desired plasma processing result for the semiconductor wafer, It is difficult to control the potential. Therefore, it is not easy to control the removal of the polymer, and if the deposition process where the polymer adheres to the sidewall and the deposit easily adheres to the surface of the semiconductor wafer is repeated, the amount of polymer attached becomes excessive, and therefore the frequency of cleaning the sidewall is increased. As a result, the operating rate of the plasma processing chamber decreases.

Therefore, in recent years, a processing chamber that actively controls the potential of the sidewall to remove the polymer on the sidewall, for example, when the operation time reaches a predetermined value, the sidewall is selectively connected to the ground or a high-frequency power source and attached to the sidewall. When removing the polymer, a processing chamber has been developed in which the side wall is connected to a high-frequency power source so that the potential of the side wall becomes a negative potential, so that cations collide with the side wall to remove the polymer on the side wall ( For example, see Patent Document 1.)
JP-A-1-231322

  However, the processing chamber according to Patent Document 1 requires a high-frequency power source for sidewalls, that is, a high-frequency power source for processing chamber components other than electrodes, in addition to the high-frequency power source for electrodes. There is a problem of complexity.

Moreover, since the processing chamber according to Patent Document 1 only removes the polymer on the side wall by connecting the side wall to a high-frequency power source when the operation time reaches a predetermined value, it is difficult to control the amount of polymer adhesion. As a result, in one plasma processing chamber, neutral active species such as the above-described deposition process and O ₂ gas used as a processing gas are not generated, and no polymer adheres to the side wall. When repeatedly performing a deposition process where no deposits adhere to the surface, if the polymer on the side wall is completely removed, the cations directly collide with the side wall, not the polymer, and the side wall is consumed. There is also a problem that the operating rate of the system decreases.

  An object of the present invention is to provide a plasma processing chamber, a potential control device, a potential control method, a program, and a storage medium that can easily control the amount of polymer adhered with a simple configuration.

  In order to achieve the above object, a plasma processing chamber according to claim 1 is provided with a container containing a substrate and an electrode disposed in the container and connected to a high-frequency power source, and introduced into the container. A plasma processing chamber in which at least two types of plasma processing can be performed on the substrate by using a processing gas as plasma, and a processing chamber component disposed in the container and exposed to the plasma, and the processing chamber component And a potential control device that sets the potential to either a floating potential or a ground potential according to each of the at least two types of plasma treatments.

  The plasma processing chamber according to claim 2 is the plasma processing chamber according to claim 1, wherein the at least two types of plasma processing are applied to a deposition process in which deposits adhere to the processing chamber components and the processing chamber components. It is a depositionless process in which no kimono adheres, and the potential control device sets the potential of the processing chamber component to the ground potential in the deposition process, and sets the potential of the processing chamber component to the floating potential in the deposition process. It is characterized by that.

  According to a third aspect of the present invention, there is provided the plasma processing chamber according to the first or second aspect, wherein the processing chamber component is electrically floated, and the potential control device includes an electrically grounded component contact member. And the component contact member is freely contactable with the processing chamber component.

  The plasma processing chamber according to claim 4 is the plasma processing chamber according to claim 3, wherein the processing chamber component has a concave hole, and the component contact member has a convex portion that can be fitted in the concave hole. It is characterized by having.

  The plasma processing chamber according to claim 5 is the plasma processing chamber according to claim 4, wherein the concave hole has a narrow portion, and at least one of the narrow portion and the convex portion is made of an elastic member. And

  The plasma processing chamber according to claim 6 is the plasma processing chamber according to claim 4 or 5, wherein the container has a cylindrical shape, and the processing chamber component is a cylindrical member that covers an inner peripheral surface of the container, The plurality of concave holes are arranged along the circumference of the cylindrical member, and the convex portions of the plurality of component contact members are freely fitted to the plurality of concave holes, respectively.

  The plasma processing chamber according to claim 7 is the plasma processing chamber according to claim 3, wherein the container has a cylindrical shape, and the processing chamber component is a cylindrical member that covers an inner peripheral surface of the container. The member has a groove formed at the end portion along the circumference of the cylindrical member, and the component contact member has a mesh shape and can be fitted into the groove.

  The plasma processing chamber according to claim 8 is the plasma processing chamber according to claim 1 or 2, wherein the processing chamber component is electrically floated, and the potential control device is configured to ground the processing chamber component. And a switching device that is arranged in the middle of the ground line and switches between disconnection and connection of the ground line.

  The plasma processing chamber according to claim 9 is the plasma processing chamber according to claim 8, wherein the potential control device includes a variable impedance element arranged in the middle of the ground line.

  The plasma processing chamber according to claim 10 is characterized in that, in the plasma processing chamber according to claim 9, the variable impedance element changes impedance according to the amount of deposits adhering to the processing chamber components. .

  The plasma processing chamber according to claim 11 is the plasma processing chamber according to claim 9 or 10, characterized in that the variable impedance element changes impedance in synchronization with the frequency of the high-frequency power source.

  The plasma processing chamber according to claim 12 is the plasma processing chamber according to any one of claims 9 to 11, wherein the variable impedance element is a variable inductance or a variable capacitor.

  In order to achieve the above object, a potential control device according to claim 13 is provided with a container that accommodates a substrate, and an electrode that is disposed in the container and connected to a high-frequency power source, and is introduced into the container. The at least two types of potentials of the processing chamber components disposed in the container of the plasma processing chamber capable of performing at least two types of plasma processing on the substrate using a processing gas as a plasma and exposed to the plasma are used. It is characterized in that either a floating potential or a ground potential is set according to each of the plasma treatments.

  A potential control apparatus according to a fourteenth aspect is the potential control apparatus according to the thirteenth aspect, wherein the at least two kinds of plasma treatments are applied to a deposition process in which deposits adhere to the processing chamber components and the processing chamber components. It is a deposition process in which no kimono adheres, and the potential of the processing chamber component is set to a ground potential in the deposition process, and the potential of the processing chamber component is set to a floating potential in the deposition process.

  The potential control device according to claim 15 is the potential control device according to claim 13 or 14, wherein the processing chamber component has a component contact member that is electrically floating and is electrically grounded. The component contact member is freely contactable with the processing chamber components.

  A potential control device according to a sixteenth aspect is the potential control device according to the thirteenth or fourteenth aspect, wherein the process chamber component is electrically floated, and a ground wire for grounding the process chamber component is formed. And a switching device that is arranged in the middle and switches between disconnection and connection of the ground wire.

  In order to achieve the above object, a potential control method according to claim 17 is provided with a container that accommodates a substrate, and an electrode that is disposed in the container and connected to a high-frequency power source, and is introduced into the container. A potential control method for processing chamber components disposed in the container of the plasma processing chamber capable of performing at least two types of plasma processing on the substrate by using a processing gas as a plasma and exposed to the plasma, In accordance with each of the at least two types of plasma processing, a potential setting step of setting a potential of the processing chamber component to either a floating potential or a ground potential is provided.

  The potential control method according to claim 18 is the potential control method according to claim 17, wherein the at least two types of plasma treatment are applied to a deposition process in which deposits adhere to the processing chamber components and the processing chamber components. In the deposition process where no kimono adheres, the potential setting step sets the potential of the processing chamber component to the ground potential in the deposition process, and sets the potential of the processing chamber component to the floating potential in the deposition process. It is characterized by that.

  In order to achieve the above object, a program according to claim 19 is provided with a processing gas introduced into a container including a container for accommodating a substrate and an electrode disposed in the container and connected to a high-frequency power source. A program for causing a computer to execute a method for controlling the potential of processing chamber components that are disposed in the container of a plasma processing chamber capable of performing at least two types of plasma processing on the substrate and are exposed to the plasma. In addition, according to each of the at least two types of plasma treatments, there is provided a potential setting module for setting the potential of the processing chamber component to either a floating potential or a ground potential.

  In order to achieve the above object, a storage medium according to claim 20 includes a container that accommodates a substrate, and an electrode that is disposed in the container and connected to a high-frequency power source, and is introduced into the container. A computer executes a potential control method of a processing chamber component that is disposed in the container of a plasma processing chamber capable of performing at least two kinds of plasma processing on the substrate by using a gas as a plasma and is exposed to the plasma. A computer-readable storage medium storing a program, wherein the program sets the potential of the processing chamber component to either a floating potential or a ground potential according to each of the at least two types of plasma processing. It has a potential setting module.

  According to the plasma processing chamber according to claim 1, the potential control device according to claim 13, the potential control method according to claim 17, the program according to claim 19, and the storage medium according to claim 20, they are arranged in a container. In addition, since the potential of the processing chamber component exposed to the plasma is set to either a floating potential or a ground potential according to each of at least two types of plasma processing, a high-frequency power source for the processing chamber component is unnecessary. In addition, the amount of deposits attached to the processing chamber components can be controlled in accordance with each plasma process, and the amount of deposits attached can be easily controlled with a simple configuration.

  According to the plasma processing chamber according to claim 2, the potential control apparatus according to claim 14, and the potential control method according to claim 18, at least two types of plasma processing are performed by a deposition process in which deposits adhere to processing chamber components. In addition, the depositor is a depositless process in which deposits do not adhere to the process chamber components, and the potential of the process chamber components is set to the ground potential in the depot process, and the potential of the process chamber components is set to the floating potential in the depot process Therefore, it is possible to prevent excessive deposits from adhering to the processing chamber components in the depot process, and to prevent the processing chamber components from being consumed in the depotless process, thereby reducing the operating rate of the plasma processing chamber. Can be prevented.

  According to the plasma processing chamber of claim 3 and the potential control apparatus of claim 15, the processing chamber component is electrically floating, and the electrically grounded component contact member is in contact with the processing chamber component. Therefore, the potential of the processing chamber components can be switched to the floating potential or the ground potential with certainty.

  According to the plasma processing chamber of claim 4, since the processing chamber component has a concave hole and the component contact member has a convex portion that can be fitted into the concave hole, the processing chamber component has a simple structure. Can be switched to a floating potential or a ground potential.

  According to the plasma processing chamber of claim 5, the concave hole of the processing chamber component has a narrow portion, and at least one of the narrow portion and the convex portion of the component contact member is made of an elastic member. The chamber component and the component contact member can be reliably contacted.

  According to the plasma processing chamber of claim 6, the container has a cylindrical shape, the processing chamber component is a cylindrical member that covers the inner peripheral surface of the container, and the plurality of concave holes extend along the circumference of the cylindrical member. Since the convex portions of the plurality of component contact members are freely fitted into the plurality of concave holes, when the process chamber component and the component contact member contact each other, the potential in the process chamber component Can be prevented from being unevenly distributed, and the amount of deposits can be uniformly controlled.

  According to the plasma processing chamber of claim 7, the container has a cylindrical shape, the processing chamber component is a cylindrical member that covers the inner peripheral surface of the container, and the cylindrical member is a circle of the cylindrical member at the end. Since the component contact member has a mesh shape and can be freely fitted to the groove, the process chamber component and the component contact member come into contact with each other. It is possible to reliably prevent the occurrence of uneven electric potential in the case, and to control the amount of deposits more uniformly.

  According to the plasma processing chamber of claim 8 and the potential control apparatus of claim 16, the processing chamber components are electrically floated, and the potential control device includes a ground wire for grounding the processing chamber components, and the ground Since the switching device is arranged in the middle of the line and switches the disconnection and connection of the ground line, the potential of the processing chamber components can be switched to the floating potential or the ground potential with a simple structure.

  According to the plasma processing chamber of claim 9, since the potential control device has the variable impedance element arranged in the middle of the ground line, the potential change speed of the processing chamber components can be controlled. The amount of deposits can be controlled more finely.

  According to the plasma processing chamber of claim 10, since the variable impedance element changes the impedance according to the amount of deposits attached to the processing chamber components, the potential of the processing chamber components according to the amount of deposits. Therefore, the amount of deposit can be controlled more finely.

  According to the plasma processing chamber of the eleventh aspect, since the variable impedance element changes the impedance in synchronization with the frequency of the high frequency power source, it is possible to suppress fluctuations in the amount of deposits during the plasma processing.

  According to the plasma processing chamber of the twelfth aspect, since the variable impedance element is a variable inductance or a variable capacitor, the adhesion amount of the deposit can be controlled more finely with a simpler configuration.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  First, the plasma processing chamber according to the first embodiment of the present invention will be described.

  FIG. 1 is a cross-sectional view showing a schematic configuration of a plasma processing chamber according to the present embodiment. This plasma processing chamber is configured to perform RIE (Reactive Ion Etching) processing or ashing processing on a semiconductor wafer W as a substrate.

  In FIG. 1, the plasma processing chamber 10 has a cylindrical container 11 in which, for example, a semiconductor wafer W having a diameter of 300 mm (hereinafter simply referred to as “wafer W”) is placed. A columnar susceptor 12 is arranged as a mounting table.

  In the plasma processing chamber 10, an exhaust path 13 that functions as a flow path for discharging gas molecules above the susceptor 12 to the outside of the container 11 is formed by the inner wall of the container 11 and the side surface of the susceptor 12. An annular baffle plate 14 is disposed in the middle of the exhaust passage 13 to prevent plasma leakage. In addition, the space downstream of the baffle plate 14 in the exhaust passage 13 wraps around below the susceptor 12 and enters an automatic pressure control valve (hereinafter referred to as “APC valve”) 15 that is a variable butterfly valve. Communicate. The APC valve 15 is connected to a turbo molecular pump (hereinafter referred to as “TMP”) 17 which is an exhaust pump for evacuation through an isolator 16, and the TMP 17 is connected to the valve V 1. Are connected to a dry pump (hereinafter referred to as “DP”) 18 which is an exhaust pump. An exhaust passage (hereinafter referred to as “main exhaust line”) constituted by the APC valve 15, the isolator 16, TMP17, the valve V1 and the DP18 performs pressure control in the container 11 by the APC valve 15, and further, TMP17 and DP18. The pressure inside the container 11 is reduced to a substantially vacuum state.

  A pipe 19 is connected between the isolator 16 and the TMP 17 to the DP 18 via the valve V2. The pipe 19 and the valve V <b> 2 (hereinafter referred to as “bypass line”) bypass the TMP 17 and roughen the container 11 by the DP 18.

  A high frequency power source 20 for the lower electrode is connected to the susceptor 12 via a feeding rod 21 and a matcher 22, and the high frequency power source 20 for the lower electrode supplies predetermined high frequency power to the susceptor 12. . Thereby, the susceptor 12 functions as a lower electrode. The matching unit 22 reduces the reflection of the high frequency power from the susceptor 12 to maximize the supply efficiency of the high frequency power to the susceptor 12.

  A disc-shaped ESC electrode plate 23 made of a conductive film is disposed above the susceptor 12. A DC power supply 24 is electrically connected to the ESC electrode plate 23. The wafer W is attracted and held on the upper surface of the susceptor 12 by a Coulomb force or a Johnson-Rahbek force generated by a DC voltage applied from the DC power source 24 to the ESC electrode plate 23. Further, an annular focus ring 25 is disposed above the susceptor 12 so as to surround the periphery of the wafer W sucked and held on the upper surface of the susceptor 12. The focus ring 25 is exposed to a space S to be described later, and the plasma is converged toward the surface of the wafer W in the space S to improve the efficiency of the RIE process and the ashing process.

  Further, for example, an annular refrigerant chamber 26 extending in the circumferential direction is provided inside the susceptor 12. A coolant having a predetermined temperature, for example, cooling water, is circulated and supplied from a chiller unit (not shown) to the coolant chamber 26 via a coolant pipe 27, and the wafer is adsorbed and held on the upper surface of the susceptor 12 by the coolant temperature. The processing temperature of W is controlled.

  A plurality of heat transfer gas supply holes 28 are opened in a portion of the upper surface of the susceptor 12 where the wafer W is adsorbed and held (hereinafter referred to as “adsorption surface”).

  The plurality of peripheral heat transfer gas supply holes 28 are connected to a heat transfer gas supply unit 32 via a heat transfer gas supply line 30 disposed inside the susceptor 12, and the heat transfer gas supply unit 32 serves as a heat transfer gas. The helium gas is supplied to the gap between the adsorption surface and the back surface of the wafer W through the heat transfer gas supply hole 28.

  A plurality of pusher pins 33 as lift pins that can protrude from the upper surface of the susceptor 12 are arranged on the suction surface of the susceptor 12. These pusher pins 33 are connected via a motor (not shown) and a ball screw (not shown), and freely protrude from the suction surface due to the rotational motion of the motor converted into a linear motion by the ball screw. To do. When the wafer W is sucked and held on the suction surface in order to perform the RIE process or the ashing process on the wafer W, the pusher pin 33 is accommodated in the susceptor 12 and the wafer W subjected to the RIE process or the ashing process is unloaded from the container 11. Sometimes, the pusher pin 33 protrudes from the upper surface of the susceptor 12 to lift the wafer W away from the susceptor 12 and lift it upward.

  A gas introduction shower head 34 is arranged on the ceiling of the container 11 so as to face the susceptor 12. A high-frequency power source 36 for the upper electrode is connected to the gas introduction shower head 34 via a matching unit 35, and the high-frequency power source 36 for the upper electrode supplies predetermined high-frequency power to the gas introduction shower head 34. The introduction shower head 34 functions as an upper electrode. The function of the matching unit 35 is the same as the function of the matching unit 22 described above.

  The gas introduction shower head 34 has a ceiling electrode plate 38 having a large number of gas holes 37 and an electrode support 39 that detachably supports the ceiling electrode plate 38. A buffer chamber 40 is provided inside the electrode support 39, and a processing gas introduction pipe 41 from a processing gas supply unit (not shown) is connected to the buffer chamber 40. A pipe insulator 42 is disposed in the middle of the processing gas introduction pipe 41. The pipe insulator 42 is made of an insulator and prevents the high-frequency power supplied to the gas introduction shower head 34 from leaking to the process gas supply section through the process gas introduction pipe 41. The gas introduction shower head 34 supplies the processing gas supplied from the processing gas introduction pipe 41 to the buffer chamber 40 into the container 11 through the gas hole 37.

  Further, on the side wall of the container 11, a wafer W loading / unloading port 43 is provided at a position corresponding to the height of the wafer W lifted upward from the susceptor 12 by the pusher pin 33, and the loading / unloading port 43 includes the loading / unloading port 43. A gate valve 44 for opening and closing 43 is attached.

  In the container 11 of the plasma processing chamber 10, as described above, high frequency power is supplied to the susceptor 12 and the gas introduction shower head 34, and high frequency power is applied to the space S between the susceptor 12 and the gas introduction shower head 34. Thus, high-density plasma is generated from the processing gas supplied from the gas introduction shower head 34 in the space S, and the wafer W is subjected to RIE processing or ashing processing by the plasma.

  Specifically, in the plasma processing chamber 10, when the RIE process or the ashing process is performed on the wafer W, the gate valve 44 is first opened, and the wafer W to be processed is loaded into the container 11. Is applied to the ESC electrode plate 23, and the loaded wafer W is sucked and held on the suction surface of the susceptor 12. Further, the processing gas is supplied from the gas introduction shower head 34 into the container 11 at a predetermined flow rate and flow ratio, and the pressure in the container 11 is controlled to a predetermined value by the APC valve 15 or the like. Further, high frequency power is applied to the space S in the container 11 by the susceptor 12 and the gas introduction shower head 34. As a result, the processing gas introduced from the gas introduction shower head 34 is converted into plasma in the space S, and the plasma is converged on the surface of the wafer W by the focus ring 25 to physically or chemically etch the surface of the wafer W.

  The operation of each component of the plasma processing chamber 10 described above is controlled by a CPU of a control unit (not shown) provided in the plasma processing chamber 10 according to a program corresponding to RIE processing and ashing processing.

  Further, the plasma processing chamber 10 has a cylindrical side wall member 45 (processing chamber component) that covers the inner peripheral surface of the cylindrical container 11. Since the side wall member 45 covers the inner peripheral surface of the container 11, the side wall member 45 faces the space S and is exposed to plasma generated in the space S. The side wall member 45 is made of aluminum, and the surface facing the space S is coated with alumite. The side wall member 45 is electrically floating (floating), and is set to obtain an anode / cathode ratio that depends on the shapes of the susceptor 12 and the side wall member 45 and a result of a desired RIE process or ashing process on the wafer W. A potential is generated in the side wall member 45 in accordance with the magnitude of the high frequency power as a process parameter, and the generated potential is controlled by a potential control device 46 described below.

  The potential control device 46 includes a round bar-like conduction member 47 (component contact member), a guide bar 48 extending in the vertical direction in the figure, a base 49 that is electrically grounded, and the conduction member 47. And an elevating part 50 that elevates and lowers the conducting member 47 along the guide rod 48. Since the conducting member 47, the base 49 and the elevating part 50 are made of a conductor, the conducting member 47 is electrically grounded via the base 49 and the elevating part 50.

  FIG. 2 is a view for explaining contact / non-contact between the conduction member and the side wall member in FIG. 1.

  In FIG. 2, the cylindrical side wall member 45 has a plurality of concave conductive member receiving holes 52 arranged along the circumference of the end portion 51 at the upper circumferential end portion 51 in the drawing. In addition, a plurality of conducting members 47 are arranged in the vertical direction in the drawing so as to face each conducting member accommodation hole 52.

  The diameter of the conducting member receiving hole 52 is slightly larger than the diameter of the conducting member 47. As shown in FIG. 3A, the conducting member receiving hole 52 is lowered downward from the end 51 by a predetermined distance in the drawing. It has a narrow portion 52a. The diameter of the narrow portion 52 a is smaller than the diameter of the conducting member 47. Further, at least one of the narrow portion 52a and the conductive member 47 is made of an elastic member, for example, aluminum or copper. Therefore, when the elevating part 50 lowers the tip (convex part) of the conduction member 47 to the narrow part 52a, the tip of the conduction member 47 and the narrow part 52a are fitted, as shown in FIG. Thereby, the conducting member 47 and the side wall member 45 are in contact with each other, and the side wall member 45 is electrically grounded via the potential control device 46. Further, when the elevating part 50 raises the conducting member 47 above the narrow part 52a, the conducting member 47 and the narrow part 52a are not in contact with each other, so that the conducting member 47 and the side wall member 45 are not in contact with each other. 45 is electrically floating. That is, the tips of the plurality of conducting members 47 are freely fitted into the plurality of conducting member receiving holes 52, respectively.

  By the way, prior to the present invention, the present inventor, in a conventional plasma processing chamber that does not include the above-described potential control device 46, adhered matter such as polymer (hereinafter referred to as “depot”) that adheres to components exposed to plasma. )) And the potential difference between each component and the space where plasma is generated, and the results are summarized in the graphs shown in FIG. 4 and FIG. Obtained knowledge.

  In FIG. 4, the depot (FIG. 4A) of the electrically floating component (hereinafter referred to as “floating part”) is the electrically grounded component (hereinafter referred to as “ground part”). It was found that the floating part is more easily attached to the floating part than the ground part. As shown in FIG. 5, since the potential difference of the ground part is larger than the potential difference of the floating part, the ions generated when the processing gas becomes plasma collide with the ground part more than the floating part. It was assumed that the deposited deposit was removed by etching with ions.

  Further, in FIG. 4, when the high frequency power of the upper electrode is fixed at 2200 W and the high frequency power of the lower electrode is set to three levels of 0/1000/3800 W, in the floating parts, the deposit is attached as the high frequency power of the lower electrode increases. It was found that the deposit is less likely to adhere to the ground part as the high frequency power of the lower electrode increases. In particular, in the ground part, it has been found that the deposition rate can be made substantially zero by increasing the high frequency power of the lower electrode. That is, it has been found that the deposit attached to the component can be almost eliminated by setting the potential of the component to the ground potential without using the high-frequency power source for the component.

  Based on these findings, in the present invention, when removing a depot from a component in a depot process where the depot adheres to the component, the potential of the component is set to the ground potential, and the depot adheres to the component. When the deposit is not removed from the component in the depotless process, the potential of the component is set to the floating potential.

  Hereinafter, a potential control method executed in the plasma processing chamber 10 will be described. Here, in the plasma processing chamber 10, two types of processing, RIE processing and ashing processing, are performed. This potential control method is executed by the CPU of the control unit in accordance with a program corresponding to the method.

First, in the RIE process, a processing gas is generated as plasma toward a resist film formed on the SiO ₂ layer of the wafer W and exposing a part of the SiO ₂ layer to the space S according to a predetermined wiring pattern. Draw ions. The drawn ions collide with the SiO ₂ layer exposed to the space S, and the SiO ₂ layer is etched according to a predetermined wiring pattern.

In the RIE process, a mixed gas of C ₄ F ₈ gas and argon gas is used as a processing gas. When this mixed gas becomes plasma, a large amount of neutral active species is generated, and the active species is used as a depot. The RIE process is a deposition process because it adheres to the side wall member 45. In this RIE process, the potential control device 46 sets the potential of the side wall member 45 to the ground potential by lowering the conductive member 47 by the elevating unit 50 and bringing the conductive member 47 and the side wall member 45 into contact with each other. The deposit attached to 45 is removed by ion etching.

In the subsequent ashing process, the resist film on the wafer W is removed by drawing ions generated by using the processing gas as plasma into the wafer W. Since the resist film is organic, O ₂ gas is used as a processing gas. Since the O ₂ gas does not generate the neutral active species as described above, and the deposit does not adhere to the surface of the side wall member 45, the ashing process is a depositless process.

When the deposit is almost removed from the side wall member 45 in the RIE process described above, ions generated when the O ₂ gas becomes plasma removes the deposit attached to the side wall member 45, and after the deposit is removed, The side wall member 45 may be exposed, and the exposed side wall member 45 may be consumed by the etching of ions. Correspondingly, in the ashing process, the potential controller 46 raises the conducting member 47 by the elevating unit 50 to bring the conducting member 47 and the sidewall member 45 into non-contact, and sets the potential of the sidewall member 45 to a floating potential. In addition, the deposit attached to the side wall member 45 is not removed. This prevents the side wall member 45 from being exposed.

  According to the plasma processing chamber and the potential control method according to the present embodiment, the potential of the side wall member 45 disposed in the container 11 and exposed to the plasma is set to the ground potential in the RIE process, and the floating potential in the ashing process. Therefore, almost no deposit attached to the side wall member 45 can be removed without using a high-frequency power source for the side wall member 45. Therefore, it is possible to easily control the deposit amount with a simple configuration. Further, it is possible to prevent deposits from being excessively attached to the side wall member 45 in the RIE process which is a deposition process, and to prevent the side wall member 45 from being consumed in the ashing process which is a depotless process. In addition, the consumption of the side wall member 45 can be prevented and the operating rate of the plasma processing chamber 10 can be prevented from decreasing.

  In addition, it becomes easy to accurately control the amount of deposits on the side wall member 45, and it is possible to suppress the peeling of the deposits from the side wall member 45 during the ashing process. Occurrence can be prevented.

  According to the above-described plasma processing chamber according to the present embodiment, the side wall member 45 is electrically floating, and the electrically grounded conductive member 47 is freely contactable with the side wall member 45. It is possible to reliably switch the potential to the floating potential or the ground potential.

  Further, according to the plasma processing chamber according to the present embodiment described above, the cylindrical side wall member 45 has the concave conductive member accommodation hole 52, and the conduction member 47 can be fitted into the conduction member accommodation hole 52. The conducting member receiving hole 52 of the side wall member 45 has a narrow portion 52a, and at least one of the narrow portion 52a and the conducting member 47 is made of an elastic member. The potential of the side wall member 45 can be switched to the floating potential or the ground potential by fitting with the narrow portion 52a or by detaching the conductive member 47 from the narrow portion 52a. The potential can be switched reliably.

  Furthermore, according to the plasma processing chamber according to the present embodiment described above, the side wall member 45 is a cylindrical member, and the plurality of conducting member accommodation holes 52 are arranged at the circumferential end portion 51 at the circumference of the end portion 51. Since the tips of the plurality of conducting members 47 are freely fitted in the plurality of conducting member receiving holes 52, when the side wall member 45 and the conducting member 47 come into contact with each other, the circumference of the side wall member 45 is Occurrence of the uneven distribution of the potential along the direction can be prevented, and the deposition amount of the deposit on the side wall member 45 can be controlled uniformly.

  In the plasma processing chamber according to the above-described embodiment, the side wall member 45 and the conduction member 47 are connected to each other by fitting the tips of the plurality of round bar-like conduction members 47 into the plurality of conduction member accommodation holes 52 of the side wall member 45. Although contacted, the conducting member 47 is not limited to a round bar shape, and may be any shape having a convex portion that can be fitted into the conducting member accommodation hole 52.

  Further, as shown in FIG. 6, the side wall member 45 has a groove 53 formed along the circumference of the end portion 51 at the circumferential end portion 51, and the potential control device 46 includes a conduction member. Instead of 47, it comprises two rings 54a, 54b having the same diameter as the groove 53 and disposed on the same central axis, and a plurality of rod-like connecting members 55 that connect the two rings 54a, 54b. You may have the net-like fitting member 56 (component contact member). The fitting member 56 is grounded via an elevating device (not shown) that moves the fitting member 56 up and down. Further, the fitting member 56 engages with the groove 53 and comes into contact with the side wall member 45 to electrically ground the side wall member 45, or is detached from the groove 53 to be out of contact with the side wall member 45. 45 is electrically floated. Needless to say, the width of the rings 54a and 54b is smaller than the groove 53, and the groove 53 has a narrow portion (not shown), and the width of the narrow portion is smaller than the width of the rings 54a and 54b.

  When the fitting member 56 is fitted to the side wall member 45, the fitting member 56 contacts the side wall member 45 over the entire circumference, so that the occurrence of potential unevenness in the circumferential direction in the side wall member 45 is ensured. Therefore, it is possible to more uniformly control the deposition amount of the deposit on the side wall member 45.

  The plasma processing chamber according to the present embodiment described above includes a lower electrode and an upper electrode, and a high frequency power source is connected to each electrode, but a high frequency power source may not be connected to the upper electrode. In this case, since the ceiling electrode plate 38 as a ceiling plate is electrically floating and the deposit adheres to the ceiling electrode plate 38 in the deposition process, a potential control device for a ceiling plate having the same configuration as the potential control device 46 is provided. The potential of the ceiling electrode plate 38 is set to the ground potential or the floating potential by controlling the contact / non-contact between the conductive member of the potential control device for the ceiling plate and the ceiling electrode plate 38, and the ceiling electrode plate 38 It is preferable to control the amount of deposits on the surface.

  Further, when the high frequency power source is not connected to the upper electrode, the side wall member 45 and the ceiling plate may be integrated. At this time, the conducting member 47 of the potential control device 46 may be in contact with either the side wall member 45 or the ceiling plate.

  Even when a high-frequency power source is connected to the upper electrode, a potential control device for a ceiling panel may be provided. As a result, in the plasma processing in which high frequency power is not supplied to the upper electrode, the potential of the ceiling electrode plate 38 can be controlled to control the deposition amount of the deposit on the ceiling electrode plate 38.

  Next, a plasma processing chamber according to a second embodiment of the present invention will be described.

  This embodiment is basically the same in configuration and operation as the first embodiment described above, and is not a potential control device 46 having a conducting member 47 that moves up and down. The only difference from the first embodiment is that the potential of the member 45 is controlled. Therefore, the description of the same configuration is omitted, and only the operation different from that of the first embodiment will be described below.

  FIG. 7 is a cross-sectional view showing a schematic configuration of the plasma processing chamber according to the present embodiment. This plasma processing chamber is also configured to perform RIE processing and ashing processing on the semiconductor wafer W, similarly to the plasma processing chamber 10 of FIG.

  In FIG. 7, the potential generated in the side wall member 45 in the plasma processing chamber 70 is controlled by a potential control device 71 described below.

  The potential control device 71 is connected to the side wall member 45, a ground wire 72 that grounds the side wall member 45, and a switch 73 (switching device) that is arranged in the middle of the ground wire 72 and switches between disconnection and connection of the ground wire 72. And have. Further, the potential control device 71 sets the potential of the side wall member 45 to a floating potential by cutting the ground line 72 with the switch 73, and sets the potential of the side wall member 45 to the ground potential by connecting the ground line 72. .

  Hereinafter, a potential control method executed in the plasma processing chamber 70 will be described. As described above, in the plasma processing chamber 70, two types of processing, RIE processing and ashing processing, are performed. This potential control method is executed by the CPU of the control unit in accordance with a program corresponding to the method.

  First, in the RIE process that is a deposition process, the potential control device 71 connects the ground line 72 by the switch 73 to set the potential of the side wall member 45 to the ground potential, and the depot adhering to the side wall member 45 is ionized. Remove by etching.

  In the ashing process that is a subsequent deposition process, the potential control device 71 sets the potential of the side wall member 45 to the floating potential by cutting the ground line 72 by the switch 73, and removes the deposit attached to the side wall member 45. do not do. This prevents the side wall member 45 from being exposed.

  According to the plasma processing chamber and the potential control method according to the present embodiment, the ground wire 72 that grounds the side wall member 45, and the switch 73 that is arranged in the middle of the ground wire 72 and that switches between disconnection and connection of the ground wire 72 are used. Since the potential of the side wall member 45 is set to the ground potential in the RIE process and is set to the floating potential in the ashing process by the potential control device 71, the potential of the side wall member 45 is set to the floating potential or the ground potential with a simple structure. Therefore, it is possible to easily control the deposit amount.

  The potential control device 71 in the plasma processing chamber according to the present embodiment described above includes the ground line 72 and the switch 73. The potential control device 71 is a variable impedance element disposed in the middle of the ground line 72, for example, a variable An inductance or a variable capacitor may be provided. Thereby, the change rate of the potential of the side wall member 45 can be controlled, so that the deposition amount of the deposit can be controlled more finely.

  In addition, the variable impedance element may change the impedance according to the amount of deposit attached to the side wall member 45. As a result, the potential of the side wall member 45 can be controlled in accordance with the amount of deposited deposit, so that the deposited amount of deposit can be controlled more finely. Furthermore, the variable impedance element may change the impedance in synchronization with the frequency of the power supplied from the high frequency power supply 20. Thereby, the fluctuation | variation of the deposition amount of the deposit resulting from the fluctuation | variation of electric power can be suppressed.

  The potential control device in the plasma processing chamber according to each of the embodiments described above includes one of a mechanical configuration (potential control device 46) and an electrical circuit configuration (potential control device 71). A general configuration and an electrical circuit configuration may be provided. Specifically, it is preferable to have a configuration in which the base 49 of the potential control device 46 is electrically grounded via a switch. In this case, when the potential of the side wall member 45 needs to be rapidly changed, the conducting member 47 is raised and lowered, while when the potential of the side wall member 45 needs to be finely adjusted, the ground line is disconnected by the switch 73. -Connect. As a result, the potential of the side wall member 45 can be set to an optimum potential in accordance with the change in the plasma processing content, and the deposition amount of the deposit can be controlled to the optimum amount.

  In the plasma processing chamber according to each of the above-described embodiments, the substrate to be processed is a semiconductor wafer. However, the substrate to be processed is not limited to this, for example, an LCD (Liquid Crystal Display) or an FPD (Flat Panel Display). It may be a glass substrate such as.

  It is an object of the present invention to refer to a storage medium storing software program codes for realizing the functions of the above-described embodiments as a computer connected to the plasma processing chamber or the above-described control unit (hereinafter referred to as “computer or the like”). And the program code stored in the storage medium is read and executed by a CPU such as a computer.

  In this case, the program code itself read from the storage medium realizes the functions of the above-described embodiments, and the program code and the storage medium storing the program code constitute the present invention.

  Examples of the storage medium for supplying the program code include RAM, NV-RAM, floppy (registered trademark) disk, hard disk, optical disk, magneto-optical disk, CD-ROM, CD-R, CD-RW, and DVD. (DVD-ROM, DVD-RAM, DVD-RW, DVD + RW), magnetic tape, non-volatile memory card, other ROM, etc. may be used as long as they can store the program code. Alternatively, the program code may be supplied to a computer or the like by downloading from another computer or database (not shown) connected to the Internet, a commercial network, a local area network, or the like.

  Further, by executing the program code read by the CPU, not only the functions of the above-described embodiments are realized, but also an OS (operating system) running on the CPU based on the instruction of the program code. Includes a case where part or all of the actual processing is performed and the functions of the above-described embodiments are realized by the processing.

 Further, after the program code read from the storage medium is written in a memory provided in a function expansion board inserted in a computer or the like or a function expansion unit connected to the computer or the like, the program code is read based on the instruction of the program code. A case where the CPU of the function expansion board or the function expansion unit performs part or all of the actual processing and the functions of the above-described embodiments are realized by the processing is also included.

  The form of the program code may be in the form of object code, program code executed by an interpreter, script data supplied to the OS, and the like.

It is sectional drawing which shows schematic structure of the plasma processing chamber which concerns on the 1st Embodiment of this invention. It is a figure for demonstrating the contact and non-contact of the conduction | electrical_connection member and side wall member in FIG. It is a figure for demonstrating the fitting state of the front-end | tip of a conduction member in FIG. 2, and a conduction-member accommodation hole, (A) is a figure which shows the state before the front-end | tip of a conduction member and a conduction member accommodation hole are fitted. (B) is a figure which shows a state when the front-end | tip of a conduction member and the conduction member accommodation hole fit. It is a graph which shows the deposition of the component in the conventional plasma processing chamber, (A) is a graph which shows the deposition of a floating part, (B) is a graph which shows the deposition of a ground part. It is a graph which shows the electrical potential difference of the component in the conventional plasma processing chamber, and the space where plasma generate | occur | produces. It is a figure for demonstrating the contact / non-contact of the fitting member and side wall member in the modification of the electric potential control apparatus in FIG. It is sectional drawing which shows schematic structure of the plasma processing chamber which concerns on the 2nd Embodiment of this invention.

Explanation of symbols

W Wafer 10, 70 Plasma processing chamber 11 Container 12 Susceptor 20 High frequency power supply 34 for lower electrode Gas introduction shower head 36 High frequency power supply 38 for upper electrode Ceiling electrode plate 45 Side wall member 46, 71 Potential control device 47 Conducting member 48 Guide rod 49 Base 50 Lifting Unit 51 End 52 Conducting Member Housing Hole 52a Narrow Part 53 Groove 54a, 54b Ring 55 Connecting Member 56 Fitting Member 72 Grounding Wire 73 Switch

Claims (20)

A container containing a substrate; and an electrode disposed in the container and connected to a high-frequency power source, and subjecting the substrate to at least two types of plasma treatment using a processing gas introduced into the container as a plasma. In a plasma processing chamber where
Process chamber components disposed within the vessel and exposed to the plasma;
A plasma processing chamber, comprising: a potential control device that sets a potential of the processing chamber components to either a floating potential or a ground potential according to each of the at least two types of plasma processing.   The at least two types of plasma treatments are a deposition process in which deposits adhere to the processing chamber components and a depositless process in which deposits do not adhere to the processing chamber components, and the potential control device includes 2. The plasma processing chamber according to claim 1, wherein the potential of the processing chamber component is set to a ground potential, and the potential of the processing chamber component is set to a floating potential in a deposition process.   The process chamber component is electrically floating, and the potential control device has an electrically grounded component contact member, and the component contact member is freely contactable with the process chamber component. The plasma processing chamber according to claim 1 or 2.   The plasma processing chamber according to claim 3, wherein the processing chamber component has a concave hole, and the component contact member has a convex portion that can be fitted into the concave hole.   The plasma processing chamber according to claim 4, wherein the concave hole has a narrow portion, and at least one of the narrow portion and the convex portion is made of an elastic member.   The container has a cylindrical shape, and the processing chamber component is a cylindrical member that covers an inner peripheral surface of the container, and a plurality of the concave holes are arranged along a circumference of the cylindrical member, 6. The plasma processing chamber according to claim 4, wherein the convex portion of the component contact member is freely fitted to each of the plurality of concave holes.   The container has a cylindrical shape, and the processing chamber component is a cylindrical member that covers the inner peripheral surface of the container, and the cylindrical member is a groove formed along the circumference of the cylindrical member at the end. The plasma processing chamber according to claim 3, wherein the component contact member has a mesh shape and can be fitted into the groove.   The processing chamber component is electrically floating, and the potential control device is a grounding wire that grounds the processing chamber component, and a switching device that is disposed in the middle of the grounding wire and switches between disconnection and connection of the grounding wire. The plasma processing chamber according to claim 1 or 2, characterized by comprising:   The plasma processing chamber according to claim 8, wherein the potential control device includes a variable impedance element disposed in the middle of the ground line.   The plasma processing chamber according to claim 9, wherein the variable impedance element changes impedance according to an amount of deposits attached to the processing chamber components.   The plasma processing chamber according to claim 9 or 10, wherein the variable impedance element changes impedance in synchronization with a frequency of the high frequency power source.   The plasma processing chamber according to any one of claims 9 to 11, wherein the variable impedance element is a variable inductance or a variable capacitor.   A container containing a substrate; and an electrode disposed in the container and connected to a high-frequency power source, and subjecting the substrate to at least two types of plasma treatment using a processing gas introduced into the container as a plasma. The potential of the processing chamber components disposed in the vessel of the plasma processing chamber capable of being exposed to and exposed to the plasma is set to either a floating potential or a ground potential according to each of the at least two types of plasma processing A potential control device characterized by:   The at least two types of plasma treatments are a deposition process in which deposits adhere to the processing chamber components and a deposition process in which deposits do not adhere to the processing chamber components, and the potential of the processing chamber components in the deposition process. 14. The potential control apparatus according to claim 13, wherein the potential of the processing chamber component is set to a floating potential in a depotless process.   14. The process chamber component has a component contact member that is electrically floating and electrically grounded, and the component contact member is freely contactable with the process chamber component. Or the electric potential control apparatus of 14.   The process chamber component is electrically floating, and has a ground line for grounding the process chamber component, and a switching device that is arranged in the middle of the ground line and switches between disconnection and connection of the ground line. The potential control device according to claim 13 or 14. A container containing a substrate; and an electrode disposed in the container and connected to a high-frequency power source, and subjecting the substrate to at least two types of plasma treatment using a processing gas introduced into the container as a plasma. A potential control method for a processing chamber component that is disposed in the vessel of the plasma processing chamber and is exposed to the plasma,
A potential control method comprising a potential setting step of setting a potential of the processing chamber component to either a floating potential or a ground potential according to each of the at least two types of plasma processing.   The at least two types of plasma treatments are a deposition process in which deposits adhere to the processing chamber components and a deposition process in which deposits do not adhere to the processing chamber components, and the potential setting step includes 18. The potential control method according to claim 17, wherein the potential of the processing chamber component is set to a ground potential, and the potential of the processing chamber component is set to a floating potential in a depotless process. A container containing a substrate; and an electrode disposed in the container and connected to a high-frequency power source, and subjecting the substrate to at least two types of plasma treatment using a processing gas introduced into the container as a plasma. A program for causing a computer to execute a potential control method for a processing chamber component that is disposed in the container of a plasma processing chamber capable of being exposed to the plasma,
A program comprising a potential setting module for setting a potential of the processing chamber component to either a floating potential or a ground potential in accordance with each of the at least two types of plasma processing. A container containing a substrate; and an electrode disposed in the container and connected to a high-frequency power source, and subjecting the substrate to at least two types of plasma treatment using a processing gas introduced into the container as a plasma. A computer-readable storage medium storing a program arranged in the container of a plasma processing chamber capable of performing and causing a computer to execute a potential control method for processing chamber components exposed to the plasma. ,
A storage medium comprising a potential setting module that sets a potential of the processing chamber component to either a floating potential or a ground potential in accordance with each of the at least two types of plasma processing.

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