JP2011086747A - Plasma processing apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a plasma processing apparatus capable of compatibly achieving removal of a reaction product deposited on a dielectric window and obtaining stability of an etching rate of a workpiece. <P>SOLUTION: An electrode 8 which is disposed facing an upper opening 2b of a chamber 2, shaped winding and spreading from a side of a center part 8a to a side of a circumferential part 8b, and operative to etch a substrate 4 held at a placement part 3 by making a reaction gas in the chamber 2 into plasma by induction coupling comprises a coil part 11 as an induction antenna component which winds and spreads from an outer circumferential surface of a vertically intermediate part of a cylinder shaft member 10 positioned at the center part 8a and applied with high-frequency electric power from an upper side, and an operation part as a capacitive antenna component such that a low-side end surface of the cylindrical shaft member 10 is disposed closely to an upper surface 5a of the dielectric window 5. Consequently, an induction component is not easily generated between the operation part and coil part and the plasma processing apparatus compatibly remove the reaction product deposited on the dielectric window and obtain the stability of the etching rate of a workpiece. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a plasma processing apparatus that performs plasma processing on a target object such as a substrate.

  In plasma processing that etches the surface of an object to be processed such as a substrate, the etching depth and surface state of the surface of the object to be processed are measured in real time when high-precision control of the etching amount or monitoring of the etching state is required. Measurement is performed at As an example of the measurement technique, an optical measurement method such as laser interference, a CCD camera, or a plasma emission analysis measurement is used, and an optical measurement device is provided outside the chamber that can be decompressed. In the plasma treatment process, light is transmitted through a derivative window provided in a part of the chamber, and the etching depth of the object to be processed, surface state observation and recognition treatment, and plasma generated in the chamber are generated. The measured light or the like is measured in real time by an optical measuring instrument.

  In order to perform these optical measurements accurately, it is desirable that the light transmittance of the derivative window is always high and stable. However, during the dry etching process in the plasma process, reaction products generated from the object to be processed adhere to the inner surface of the chamber. For this reason, the reaction product adheres to and accumulates on the derivative window, resulting in gradual cloudiness, and the light transmittance of the derivative window is lowered, making it difficult to carry out accurate optical measurements continuously.

  In order to prevent such problems due to adhesion of reaction products, a plasma processing apparatus having a function of removing reaction products deposited on the derivative window has been used (for example, Patent Document 1). In the prior art example shown in this patent document, the reaction product deposited on the derivative window by bringing the path of the excitation coil for generating plasma by inductive coupling inside the chamber (inside the reaction chamber) close to the dielectric window Is used as an action part for removing the film by the sputtering effect.

JP 2006-73801 A

  However, in the above prior art examples, the following problems are involved in efficiently performing the etching process while achieving both the removal of the reaction product deposited on the dielectric window and the stability of the etching rate of the object to be processed. there were. That is, in the configuration of the above-described prior art example, the reaction product deposited on the derivative window is removed by making the path of the excitation coil in the vicinity of the dielectric window as an action part, but between the excitation coil and the action part. The inductive component that is generated tends to be a factor that inhibits the inductive component for etching by the excitation coil, and this is an unstable factor that impairs the uniformity of the etching rate of the object to be processed.

  In order to prevent this, in Cited Document 1 (see paragraph 0024), an inductive component is prevented from being generated between the excitation coil and the action part by devising the shape of the action part. However, since the action part is formed in the path of the excitation coil in the above-described configuration, when applying high-power high-frequency power to the excitation coil, the reaction product deposited on the derivative window is removed by the action part and the object to be processed In order to achieve both the stability of the etching rate, there has been a problem that a complicated balance adjustment is required to appropriately set the shape of the action portion and the like.

  Accordingly, an object of the present invention is to provide a plasma processing apparatus capable of achieving both the removal of reaction products deposited on a dielectric window and the stability of the etching rate of an object to be processed.

  The plasma processing apparatus of the present invention is disposed so as to face a chamber capable of being depressurized, a mounting portion that is provided on the lower side of the chamber and holds an object to be processed, and an upper opening provided in the chamber. The high-frequency power is applied to the central part and has a shape that spreads from the central part side to the peripheral part side, the reaction gas in the chamber is turned into plasma by inductive coupling, and the object to be processed held in the mounting part is An electrode for etching, a dielectric window having a light transmitting portion that is transparent below the electrode and seals the upper opening of the chamber, and is disposed above the electrode; An optical measuring instrument capable of measuring or observing the object to be processed in the chamber through a gap in a plan view of the electrode and the light transmission part of the dielectric window; Position A central support shaft to which high-frequency power is applied from the upper side, a coil portion as an induction antenna component spreading from an outer peripheral surface of an intermediate portion in the vertical direction of the central support shaft, and an end surface on the lower side of the central support shaft Has an action portion as a capacitive antenna component arranged close to the upper surface of the dielectric window.

  According to the present invention, the reaction gas in the chamber is disposed so as to face the upper opening of the chamber for plasma processing, and has a shape in which high-frequency power is applied to the central portion and spreads from the central portion side to the peripheral portion side. An electrode for etching the object to be processed held in the mounting part by inductive coupling into a plasma, a central support shaft that is located at the center and to which high-frequency power is applied from the upper side, and upper and lower of the central support shaft A coil portion as an induction antenna component that spreads from the outer peripheral surface of the intermediate portion in the direction, and a function portion as a capacitive antenna component in which the lower end surface of the central support shaft is disposed close to the surface of the dielectric window As a result, an inductive component is hardly generated between the action part and the coil part, and it is possible to achieve both the removal of the reaction product deposited on the dielectric window and the stability of the etching rate of the workpiece. .

Sectional drawing which shows the structure of the plasma processing apparatus of Embodiment 1 of this invention 1 is an exploded perspective view of a plasma processing apparatus according to a first embodiment of the present invention. Structure explanatory drawing of the coil part of an electrode and an action part in the plasma processing apparatus of Embodiment 1 of this invention Structure explanatory drawing of the coil part of an electrode and an action part in the plasma processing apparatus of Embodiment 1 of this invention Structure explanatory drawing of the coil part of an electrode and an action part in the plasma processing apparatus of Embodiment 1 of this invention Sectional drawing which shows the structure of the plasma processing apparatus of Embodiment 2 of this invention Explanatory drawing of the recessed part provided in the dielectric material window in the plasma processing apparatus of Embodiment 2 of this invention. Explanatory drawing of the recessed part provided in the dielectric material window in the plasma processing apparatus of Embodiment 2 of this invention. Explanatory drawing of the recessed part provided in the dielectric material window in the plasma processing apparatus of Embodiment 2 of this invention.

(Embodiment 1)
First, with reference to FIG. 1 and FIG. 2, the structure of the plasma processing apparatus 1 in Embodiment 1 of this invention is demonstrated. 1 and 2, a chamber 2 is a substantially cylindrical container having a processing chamber 2a for plasma processing therein, and an upper opening 2b that opens upward is provided on the upper surface side. A placement unit 3 is provided below the processing chamber 2 a, and a substrate 4 that is an object to be processed is held on the top surface of the placement unit 3.

  A dielectric window 5 that seals the processing chamber 2a by sealing the upper opening 2b is disposed below the electrode 8 described below. The dielectric window 5 is made of a transparent material that can transmit light, such as quartz or sapphire. As will be described later, the substrate 4 held on the mounting portion 3 is optically measured from the outside of the processing chamber 2a by the optical measuring instrument 14. It can be measured and observed. In other words, the dielectric window 5 has a light transmitting portion 5c (FIG. 2) that is transparent and can transmit light.

  Further, an evacuation device 6 and a gas supply source 7 are connected to the openings 2 c and 2 d provided on the side surface of the chamber 2, respectively. By driving the evacuation apparatus 6, the inside of the processing chamber 2a is evacuated and decompressed. That is, the chamber 2 can be depressurized. Then, by driving the gas supply source 7, a reaction gas for etching the substrate 4 is supplied into the processing chamber 2a. The vacuum exhaust device 6, the gas supply source 7, and the high-frequency power application device 9 are controlled by the controller 15, whereby plasma processing for the substrate 4 is executed.

  On the upper surface 5a side of the dielectric window 5, an electrode 8 is provided for etching the substrate 4 held on the mounting portion 3 by converting the reaction gas in the processing chamber 2a of the chamber 2 into plasma by inductive coupling. ing. The electrode 8 is disposed so as to face the upper opening 2b provided in the chamber 2, and as shown in FIG. 2, the high frequency power is applied by the high frequency power application device 9 from the central portion 8a side to the peripheral portion 8b side. A plurality of coil portions 11 (here, four of the coil portions 11 a to 11 d) have a shape that spreads in a spiral shape. A cylindrical shaft member 10 as a central support shaft that supports the ends of the plurality of coil portions 11 is disposed in the central portion 8a in a vertical posture.

  As shown in FIG. 3, the cylindrical shaft member 10 has a hollow shape having a hollow portion 10a penetrating in the vertical direction. The connection terminal 9a for connecting the cylindrical shaft member 10 to the high frequency power application device 9 is coupled to one side of the outer peripheral surface of the upper portion of the cylindrical shaft member 10, and the high frequency power supplied from the high frequency power application device 9 is the cylindrical shaft. The member 10 is configured to be applied from the upper side periphery. The coil portions 11a to 11d are arranged to extend in a spiral shape from four equal positions in plan view on the outer peripheral surface 10d of the cylindrical shaft member 10.

  Moreover, the height position where the coil parts 11a-11d extend from the cylindrical shaft member 10 is as shown in FIG.3 (b), and the cylindrical shaft member 10 with which the connection terminal 9a was couple | bonded in the outer peripheral surface 10d of the intermediate part 10c. It is set at a position away from the top by a predetermined distance D. Here, the predetermined distance D is a coil portion 11a for extending high-frequency power supplied from a different position on the outer peripheral surface 10d through a connection terminal 9a coupled to a position biased to one side in the upper part of the cylindrical shaft member 10. It is a distance required to transmit to ˜11d substantially evenly. Further, the cylindrical shaft member 10 extends downward from the height positions of the coil portions 11a to 11d, the lower end surface 10b of the cylindrical shaft member 10 is close to the upper surface 5a of the dielectric window 5, and the end surface 10b and the upper surface 5a. A predetermined gap G is maintained between the two.

  When high-frequency power is applied from the high-frequency power application device 9 to the electrode 8 having the above-described configuration via the connection terminal 9 a, high-frequency current flows through the coil portions 11 a to 11 d, and electromagnetic induction action due to this high-frequency current is transmitted through the dielectric window 5. As a result, the plasma P in which the reaction gas is ionized by inductive coupling is generated in the processing chamber 2a. In the electrode 8, the coil portions 11a to 11d function as an induction antenna component that exerts an electromagnetic induction action in the processing chamber 2a (see an elliptical frame 12 indicated by a dotted line in FIG. 1).

  When high frequency power is applied to the electrode 8 via the connection terminal 9 a, an electric field due to the potential of the end face 10 b close to the upper surface 5 a acts in the processing chamber 2 a via the dielectric window 5. Due to the capacitive coupling between the end face 10 b and the dielectric window 5, a self-bias in which electrons in the processing chamber 2 a collide and negatively charge is generated at a position immediately below the end face 10 b on the lower surface 5 b of the dielectric window 5. As a result, a sputtering effect in which positive ions in the processing chamber 2a collide occurs at a position immediately below the end face 10b, and reaction products adhering to the lower surface 5b of the dielectric window 5 during the plasma processing process are caused by this sputtering effect. Removed. In the electrode 8, the end surface 10 b of the cylindrical shaft member 10 is disposed close to the upper surface 5 a of the dielectric window 5, and a capacitive antenna component (circular indicated by a dotted line in FIG. 1) that generates a sputtering effect at a position immediately below the end surface 10 b. It has the function of the action part as a frame 13).

  That is, in the present embodiment, the electrode 8 is located at the central portion 8a and the cylindrical shaft member 10 that is a central support shaft to which high frequency power is applied from the upper side by the high frequency power applying device 9; A capacitive antenna component in which the coil portion 11 serving as an induction antenna component extending from the outer peripheral surface 10d of the intermediate portion 10c in the vertical direction and the lower end surface of the cylindrical shaft member 10 are disposed close to the upper surface 5a of the dielectric window 5 It has the structure which has an action part (end surface 10b) as.

  In the example shown in FIG. 3, in the electrode 8, the cylindrical shaft member 10 serving as a central support shaft to which high-frequency power is applied from the upper side periphery has a hollow shape, and the coil portions 11 a to 11 d serving as induction antenna components are plasma. A predetermined distance D set to prevent the bias of the high frequency power of the coil portions 11 a to 11 d on the outer peripheral surface 10 d of the intermediate portion 10 c of the cylindrical shaft member 10 from the application position of the high frequency power around the upper side of the processing apparatus 1. However, it has a form that spreads from a position apart in the vertical direction.

  Above the electrode 8, an optical measuring instrument 14 is arranged with the measuring optical axis 14 a aligned with the hollow portion 10 a of the cylindrical shaft member 10 positioned at the center of the plane of the chamber 2. The plane center of the chamber 2 is a function such as an optical measuring instrument 14 such as a laser displacement meter, measurement of the etching depth of the substrate 4 that is the object to be processed held in the mounting section 3 in the processing chamber 2a, and observation of the etching state. It is what has. The result of measurement / observation by the optical measuring instrument 14 is transmitted to the controller 15, and the controller 15 controls the evacuation device 6, the gas supply source 7, and the high-frequency power application device 9 based on this result, so that plasma corresponding to the purpose is obtained. Processing can be executed with high accuracy.

  Measurement or observation by the optical measuring instrument 14 is performed by transmitting light through the hollow portion 10a of the cylindrical shaft member 10, that is, the gap in the plan view of the electrode 8 and the light transmitting portion 5c of the dielectric window 5. Here, as described above, since the sputtering effect is always applied to the position immediately below the end face 10b on the lower surface 5b of the dielectric window 5, that is, the lower surface of the light transmitting portion 5c, in the plasma processing process, the deposition of reaction products is deposited. No fogging due to the occurrence of fogging, and good light transmittance is maintained. Therefore, the optical measurement / observation by the optical measuring instrument 14 can be performed accurately and continuously.

In the embodiment described above, the hollow cylindrical shaft member 10 is used as the central support shaft. However, as shown in FIG. 4, the cross shaft member 18 having a cross-shaped horizontal cross section is used as the central support shaft. May be. In FIG. 4, the cross shaft member 18 has a cross shape in which four edge portions 18 a to 18 d are extended from the center in four directions equally spaced by 90 °. In this case, the planar position of the optical measuring instrument 14 is arranged so that the measurement optical axis 14a is offset from the center of the horizontal cross section of the cross shaft member 18 by the thickness of the member cross section. That is, also in the example shown in FIG. 4, the optical measuring instrument 14 measures and observes the substrate 4 in the chamber 2 through the gap in the plan view of the electrode 108 and the light transmission part 5 c of the dielectric window 5.

  Similarly, the coil portions 11a to 11d are arranged so as to extend in a spiral shape from four equal positions in a plan view of the cross shaft member 18. The connection terminal 9 a that connects the cross shaft member 18 to the high frequency power application device 9 is coupled to the center of the upper portion of the cross shaft member 18, and the high frequency power supplied from the high frequency power application device 9 is upper in the cylindrical shaft member 10. Applied from the center of the side. The cross shaft member 18 extends downward from the height position of the coil portions 11a to 11d, the lower end surface 18e of the cross shaft member 18 is close to the upper surface 5a of the dielectric window 5, and the end surface 18e and the upper surface 5a A predetermined gap G is maintained between the two. Also in this case, as in the example shown in FIG. 3, the end face 18e of the cross shaft member 18 is disposed in the vicinity of the upper surface 5a of the dielectric window 5, and a capacitive antenna that generates a sputtering effect at a position directly below the end face 18e. It has the function of the action part as a component.

  In the example shown here, the application position of the high frequency power is the center of the upper part of the cross shaft member 18, and the coil portions 11a to 11d are coupled in a radial configuration from the center, so that each of the coil portions 11a to 11a. In 11d, power is evenly transmitted from the high-frequency power applying device 9 without deviation. Therefore, in the example shown in FIG. 3, it is not necessary to consider the predetermined distance D required to transmit power to the coil portions 11a to 11d without deviation. As a result, as shown in FIG. 4B, the coil portions 11a to 11d can be coupled to the upper portions of the edge portions 18a to 18d with their upper end surfaces aligned.

  That is, in the example shown in FIG. 4, in the electrode 8, the cross shaft member 18 as a central support shaft to which high-frequency power is applied from the center on the upper side has a radial shape spreading from the center to the periphery, and the lower side of the cross shaft member 18. The end face 18e is an action portion as a capacitive antenna component disposed in the vicinity of the surface 5a of the dielectric window 5. By adopting such a configuration, it is possible to secure as large an interval as possible between the coil portions 11a to 11d constituting the induction antenna component and the end face 18e that is the action portion. Thereby, the influence which the induction | guidance | derivation component of coil part 11a-11d exerts on an action part can be suppressed, and it is possible to ensure the fog prevention effect of the light transmissive part 5c, without causing the fall of the etching rate with respect to the board | substrate 4. It has become.

  3 and 4, the positions of the cylindrical shaft member 10 and the cross shaft member 18 disposed in the central portion 8a are fixed with respect to the dielectric window 5, and the cylindrical shaft member 10 The interval between the end surface 10b of the cross shaft member 18 and the end surface 18e of the cross shaft member 18 and the upper surface 5a of the dielectric window 5 is a fixed predetermined interval G set in advance. On the other hand, in the example shown in FIG. 5A, the cylindrical shaft member 110 that constitutes the action portion in the vicinity of the upper surface 5a is a separate body that can be moved and adjusted in the vertical direction with respect to the hollow portion 10A. In the example shown in FIG. 5B, the cross shaft member 118 that constitutes the action portion in the vicinity of the upper surface 5a is a separate body that can be moved and adjusted in the vertical direction with respect to the edge portion 18A.

  That is, in the example shown here, the capacitive antenna in which the end surfaces 110a and 118a on the lower side of the cylindrical shaft member 10A and the cross shaft member 18A, which are the central support shafts of the electrodes 8, are arranged close to the surface 5a of the dielectric window 5. The action portion as a component is configured as a separate body that can be moved and adjusted in the vertical direction with respect to the cylindrical shaft member 10A and the cross shaft member 18A. By adopting such a configuration, the distance G between the end surfaces 110a and 118a and the upper surface 5a of the dielectric window 5 is appropriately adjusted according to the magnitude of the high-frequency power applied by the high-frequency power application device 9. It is possible to set the effect of the action part as a capacitive antenna component to a desired state.

As described above, in the configuration of the electrode 8 shown in FIGS. 1 to 5, the coil portion 11 to which high-frequency power is applied and functions as an induction antenna component is disposed on the lower side of the central support shaft as a capacitive antenna component. It becomes the structure by which an end surface (action part) is connected in parallel. For this reason, an inductive component is hardly generated between the coil portion as the inductive antenna component and the action portion as the capacitive antenna component, and the reaction product deposited on the lower surface 5b of the dielectric window 5 is removed and the etching rate of the substrate 4 is increased. And balance adjustment is easy.

  1 to 5, the cylindrical shaft member 10 of the electrode 8, the end surface 10 b of the cross shaft member 18, and the end surface 18 e are positioned at the position of the lower surface 5 b opposite to the position of the upper surface 5 a of the dielectric window 5. In addition to providing a cylindrical recess (see recess 21 shown in FIG. 6) that opens toward the mounting portion 3 on which the substrate 4 is held, a reactive gas or a noble gas for etching the substrate 4 from the inside of the recess The internal pressure in the recess may be made higher than the internal pressure near the lower surface 5b of the dielectric window 5 in the chamber 2. This makes it difficult for the reaction product when etching the substrate 4 to enter the recess, and prevents the reaction product from adhering to the dielectric window 5 to prevent the light transmission portion 5c from being fogged. be able to.

(Embodiment 2)
Next, the configuration of the plasma processing apparatus 101 according to the second embodiment will be described with reference to FIG. In FIG. 6, the chamber 2 is the same as that shown in FIG. 1 of the first embodiment, and a mounting portion 3 is provided below the processing chamber 2a. The substrate 4 which is a body is held. Here, the lower part of the chamber 2 is not shown.

  A dielectric window 105 that seals the processing chamber 2a by sealing the upper opening 2b is disposed above the chamber 2 so as to be positioned below the electrode 108 corresponding to the electrode 8 in the first embodiment. The electrode 108 is disposed so as to face the upper opening 2b, and has a shape in which a plurality of coil portions 11 are spirally wound from the central portion 108a side to which the high frequency power is applied by the high frequency power applying device 9 to the peripheral portion 108b side. have. However, the electrode 108 does not have a central support shaft like the cylindrical shaft member 10 in the electrode 8, and is configured to include only the induction antenna component indicated by the dotted oval frame 12.

  Above the electrode 108, an optical measuring instrument 14 similar to that of the first embodiment is disposed with the measurement optical axis 14 a aligned with the plane center of the chamber 2. Measurement or observation by the optical measuring instrument 14 is performed by transmitting light through a gap in the plan view of the central portion 108a and a light transmitting portion provided in the dielectric window 105 (see the light transmitting portion 5c shown in FIG. 2). Done. The dielectric window 105 is made of a transparent material capable of transmitting light, such as quartz or sapphire, like the dielectric window 5 in the first embodiment.

  In the second embodiment, the reaction gas supplied from the gas supply source 7 is supplied into the processing chamber 2 a via the shower-like gas supply path 20 formed in the dielectric window 105. The gas supply path 20 is connected to the gas supply source 7 to guide the reaction gas to the central position of the upper opening 2b, and branches in a horizontal direction from a portion where the end of the gas introduction hole 20a is bent downward. A gas branch hole 20b and a plurality of gas injection holes 20c branched downward from the gas branch hole 20b and opened in the lower surface 105b of the dielectric window 105 to inject the reaction gas into the processing chamber 2a. The position where the end portion of the gas introduction hole 20a is bent downward at the center position of the upper opening 2b and opens to the lower surface 105b is the gas blowing center portion in the gas supply path 20 described above. A cylindrical concave portion 21 opened to the placement portion 3 side is provided in the central portion of the gas blowing, and the gas injection hole 20 c located in the center is opened in the bottom surface 21 a of the concave portion 21.

  The bottom surface 21 a of the recess 21 has a planar shape and can transmit light, and the bottom surface 21 a is a light transmission portion provided in the dielectric window 105. The light for measurement or observation by the optical measuring instrument 14 passes through the bottom surface 21a of the recess 21 as shown in FIG. Here, as described above, the reactive gas for the plasma processing is supplied into the processing chamber 2a through the gas supply path formed in the dielectric window 105, and the recess 21 is formed through the gas injection hole 20c located in the center. It also erupts inside.

  As a result, the internal pressure P1 in the recess 21 is higher than the internal pressure P2 near the lower surface 105b of the dielectric window 105 in the processing chamber 2a. As a specific numerical example, the internal pressure P2 in the vicinity of the lower surface 105b is substantially equal to the processing pressure in the processing chamber 2a (for example, about 1.3 pa), and the internal pressure P1 in the recess 21 is a viscous flow region (for example, 229 pa). The shape and size of the gas supply path 20 and the recess 21 and the gas flow rate (for example, 200 sccm) are set so that

  The internal pressure P2 shown in the above numerical value is a molecular flow region, and in the plasma processing for the purpose of etching the substrate 4, reaction product fine particles scattered from the substrate 4 pass through the processing chamber 2a in the dielectric window 105. It moves freely toward the lower surface 105b. On the other hand, in the vacuum pressure region of the internal pressure P1 shown in the above-mentioned numerical value, the reaction gas ejected into the recess 21 has a viscous flow property, and thus moves from the inside of the processing chamber 2a toward the inside of the recess 21. Movement of the fine particles of the reaction product is hindered by the flow of the reaction gas, and entry into the recess 21 is suppressed. That is, the reaction product is hardly deposited on the bottom surface 21a of the recess 21 and fogging due to the reaction product is not generated, and a good light transmittance is maintained. Therefore, measurement and observation by the optical measuring instrument 14 can always be performed accurately.

  That is, in the plasma processing apparatus 101 shown in the second embodiment, a cylindrical shape having a bottom surface 21a that is open to the mounting portion 3 side, has a planar shape, and can transmit light, on the lower surface 105b side of the dielectric window 105. The recess 21 is provided, and a reactive gas or a rare gas for etching the substrate 4 as an object to be processed is ejected from the inside thereof, whereby the internal pressure P1 in the recess 21 is reduced to the lower surface 105b of the dielectric window 105 in the chamber 2. It has a form that is higher than the nearby internal pressure P2.

Note that the low vacuum (100 Pa or higher) region is a viscous flow. In the viscous flow region, there is sufficient collision between molecules, and the reaction gas or rare gas is a continuous fluid with a liquid-like concept. Can be captured. As a result, the gas outflow (spout) velocity Vo of the gas injection hole 20c that is opened in the lower surface 105b side of the dielectric window 105 and that is opened in the bottom surface 21a of the recess 21 of the dielectric window 105 is It is simply expressed by the following calculation formula (Formula 1).
Vo = Q * (101325 / (P + ΔP)) * (T / 273) / (A * x) (1)

Here, the gas outlet (outlet) speed Vo = 323 m / s, the gas flow rate Q = 200 sccm = 3.33 * 10 ⁻⁶ m ³ / s, the gas temperature T = 300 K, the outlet of the gas injection hole 20 c. The cross-sectional area A = 1 * 10 ⁻⁶ m ^{2 of} the (outlet), the pressure P = 1.3P of the chamber 2 (internal pressure P2 near the lower surface 105b), the reaction gas from the lower surface 105b side of the dielectric window 105 into the chamber 2 Alternatively, the number of gas holes (spout ports) x = 5 in the gas injection holes 20c through which the rare gas is injected (the center one of them is the gas injection hole 20c opened in the bottom surface 21a of the recess 21) and In this case, from the above formula (formula 1), the pressure difference ΔP (internal pressure P1 in the recess 21) of the outflow portion (spout portion) with respect to the pressure P of the chamber 2 is 229 Pa. Similarly, (Table 1) shows the value of the outflow part pressure ΔP when the number x of gas holes (jet ports) is 1, 4, and 8.

  Further, here, the concave portion 21 which is a light transmitting portion provided in the dielectric window 105 is provided in the central part of the gas blowing in the shower-like gas supply path 20 configured in the dielectric window 105. It is possible to perform a well-balanced injection of reaction gas from the gas supply source 7 to the peripheral portion in the processing chamber 2a through the plurality of gas injection holes 20c branched from the gas blowing center side and provided in the periphery. it can. Thereby, in the processing chamber 2a, the reactive gas can be uniformly supplied to the portion corresponding to the peripheral portion 108b where the coil winding density of the electrode 108 is high, and a stable plasma distribution can be realized. .

  In the example shown in FIG. 7, the example in which the reactive gas or the rare gas is ejected from the bottom surface 21a in the concave portion 21 provided in the dielectric window 105 is shown. However, as shown in FIG. A gas injection hole 20d opened in the side wall 21b may be provided, and the reaction gas or the rare gas may be ejected into the recess 21 from the side wall 21b. Thereby, the internal pressure P1 in the recess 21 is made higher than the internal pressure P2 near the lower surface 105b of the dielectric window 105. At this time, since the reaction gas is injected from the side wall 21b, a gas flow that flows in the lateral direction is generated in the recess 21, and this gas flow effectively prevents the reaction product from adhering to the bottom surface 21a. it can.

  Further, as described above, when the configuration in which the reactive gas is ejected from the gas injection hole 20d is adopted, as shown in FIG. 9, one of the dielectric windows 105 corresponding to the bottom surface 21a of the concave portion 21 which is a light transmission portion. The part can be a separate replaceable part. That is, as shown in FIG. 9A, on the upper surface 105a of the dielectric window 105, a portion corresponding to the upper part of the concave portion 21 is removed in a circular shape to form a fitting concave portion 105d and fitted into the fitting concave portion 105d. A light transmitting member 25 made of a material that can transmit light in a shape is prepared. When the plasma processing apparatus 101 is in operation, the light transmitting member 25 is fitted into the fitting recess 105 d and the light transmitting member 25 is sealed by the seal member 26 as shown in FIG. 9B.

  Thereby, the lower surface of the light transmission member 25 functions as the bottom surface 21 a of the recess 21. By adopting such a configuration, when the operation of the apparatus is continued for a long time, even if the lower surface 105a of the dielectric window 105 is worn by sputtering, the light in the chamber 2 can be replaced by replacing only the light transmitting member 25. The light transmittance during optical measurement by the measuring instrument 14 can be kept good. Therefore, the cost of replacement parts required for apparatus maintenance can be reduced, and the light transmission member 25 can be easily replaced from the upper side, so that the time and labor required for maintenance work can be shortened. .

The plasma processing apparatus of the present invention has an effect that it is possible to achieve both the removal of reaction products deposited on the dielectric window and the stability of the etching rate of the target object, and the surface of the target object such as a substrate. Can be used in the field of etching.

DESCRIPTION OF SYMBOLS 1,101 Plasma processing apparatus 2 Chamber 2a Processing chamber 2b Upper opening 3 Placement part 4 Substrate 5, 105 Dielectric window 8, 108 Electrode 8a, 108a Central part 8b, 108b Peripheral part 10 Cylindrical shaft member 10a Hollow part 10b End surface 11 11a, 11b, 11c, 11d Coil unit 14 Optical measuring device 18 Cross shaft member 18e End surface 20 Gas supply path 21 Recessed portion 21a Bottom surface 21b Side wall 25 Light transmitting member

Claims (5)

A chamber capable of being depressurized, and a mounting portion that is provided on the lower side of the chamber and holds an object to be processed;
It is arranged so as to face the upper opening provided in the chamber, has a shape spreading from the central part side to which the high-frequency power is applied, to the peripheral part side, and the reaction gas in the chamber is converted into plasma by inductive coupling as described above An electrode for etching the object to be processed held in the mounting portion;
A dielectric window having a transparent portion that is transparent to transmit light and is located below the electrode by sealing the upper opening of the chamber;
An optical measuring instrument that is disposed above the electrode and is capable of measuring or observing the object to be processed in the chamber via a gap in a plan view of the electrode and the transmission part of the dielectric window;
The electrode is a central support shaft that is located at the center and to which high-frequency power is applied from the upper side, and a coil portion as an induction antenna component that extends from the outer peripheral surface of the intermediate portion in the vertical direction of the center support shaft, The plasma processing apparatus according to claim 1, wherein a lower end face of the central support shaft has an action portion as a capacitive antenna component disposed close to the surface of the dielectric window.   In the electrode, the central support shaft to which the high frequency power is applied from the upper side periphery has a hollow shape, and the coil part as the induction antenna component is from the application position of the high frequency power around the upper side of the central support shaft, The plasma processing apparatus according to claim 1, wherein the plasma processing apparatus spreads from a position separated in a vertical direction by a predetermined distance set in order to prevent bias of high-frequency power of the coil portion on the outer peripheral surface of the intermediate portion.   In the electrode, a central support shaft to which high-frequency power is applied from the center on the upper side has a radial shape extending from the center to the periphery, and an end surface on the lower side of the center support shaft is disposed close to the surface of the dielectric window. The plasma processing apparatus according to claim 1, wherein the plasma processing apparatus is an action portion serving as a capacitive antenna component.   The acting portion as a capacitive antenna component in which the lower end surface of the central support shaft of the electrode is disposed close to the surface of the dielectric window is separately movable and adjustable with respect to the central support shaft. The plasma processing apparatus according to claim 1, wherein the plasma processing apparatus is formed of a body.   The mounting portion in which the object to be processed is held at a position on the lower surface side of the dielectric window facing the position of the electrode side surface of the dielectric window in which the end surface of the hollow central support shaft of the electrode is close A cylindrical recess that opens toward the side is provided, and a reactive gas or a rare gas for etching the object to be processed is ejected from the inside, thereby reducing the internal pressure of the cylindrical recess to the dielectric in the chamber. 5. The plasma processing apparatus according to claim 1, wherein the pressure is higher than the internal pressure in the vicinity of the lower surface of the window.

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