JP2004165645A - Plasma processing apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a plasma processing apparatus, capable of uniformizing plasma processing within substrate surface by correcting the distortion of electric field and the distortion of the plasma, in an edge part in a plasma processing apparatus in which a substrate to be processed is installed on the applying electrode side. <P>SOLUTION: The plasma processing apparatus applys a plasma processing onto a substrate 8 to be processed, which is loaded on a cathode electrode 6 inside a processing chamber, by introducing a source gas into the processing chamber and generating plasma in the processing chamber. The apparatus is characterized in that a ring 10a, which includes the outer peripheral edge of the substrate 8 to be processed and which has a clearance between the inclusive face and the upper surface of the substrate 8 to be processed, is installed. <P>COPYRIGHT: (C)2004,JPO

Description

  The present invention relates to a plasma processing apparatus for a semiconductor manufacturing apparatus and a liquid crystal manufacturing apparatus.

  A plasma processing apparatus in a semiconductor manufacturing apparatus and a liquid crystal manufacturing apparatus exhausts the inside of a vacuum vessel while supplying a gas into the vacuum vessel, and controls the inside of the vacuum vessel to a predetermined pressure while using a plasma source or an electrode in a vacuum vessel. By supplying high-frequency power to both of them, an electric field is generated in the vacuum vessel, the reaction gas is turned into plasma by the electric field, and the substrate mounted on the electrode in the vacuum vessel is subjected to plasma processing. In this case, when the substrate is placed on the side of the cathode electrode to which the high-frequency power is applied, unless the plasma sheath on the substrate surface is uniformly distributed on the substrate surface, the plasma sheath on the substrate surface is not disposed. It becomes difficult to obtain a plurality of plasma processing characteristics uniformly, and in practice, it is inevitable that the plasma characteristics vary to some extent in the substrate surface. In particular, the plasma sheath on the substrate surface becomes extremely large at the outer edge of the substrate, and is directly affected when the plasma processing characteristics are obtained in accordance with the distribution of the plasma sheath. For example, in a dry etching apparatus, the etching rate tends to be higher in the peripheral portion of the substrate than in the central portion.

  Therefore, as a method for obtaining plasma processing characteristics that are affected by the distribution of the plasma sheath uniformly in the substrate surface, a ring around the substrate whose height from the substrate surface is not constant throughout the entire surface is uniformly formed from the substrate. Standing at a distance so as to surround the periphery of the substrate, controlling the inflow of the reaction gas around the substrate and the outflow of the reaction products, thereby reducing the reaction speed at the outer periphery of the substrate and reducing the variation in the etching rate. Technology exists as a known technology (for example, see Patent Document 1).

  Next, a conventional dry etching apparatus described in Patent Document 1 will be described with reference to FIGS. The conventional dry etching apparatus described in Patent Literature 1 evacuates a vacuum pump 111 as an exhaust device while introducing a predetermined flow rate of gas from a gas supply device 112 into a vacuum vessel 111 as shown in FIG. While maintaining the inside of the vacuum vessel 111 at a predetermined pressure, high-frequency power is supplied to the lower electrode 115 and the plasma source 117 from the electrode high-frequency power supply 114 and the plasma source high-frequency power supply 118 to generate plasma in the vacuum vessel 111. An etching process is performed on the substrate 116 mounted on the lower electrode 15. The ring 119 surrounds the entire periphery of the substrate 116 around the substrate 106, and the height from the surface of the substrate 106 is not uniform throughout the entire periphery. , The etching rate at the periphery of the substrate 116, particularly at the corners, can be selectively set with respect to the center. Pressing, and performs dry etching uniform etching rate is obtained as a whole.

  Conventionally, this technology has achieved uniformity of the etching rate with a focus ring of a certain height, but in order to obtain more uniformity of the etching rate as the etching process is diversified, It is characterized by providing a ring whose height is not uniform over the entire circumference.

  However, this method is an approach in which the variation in plasma processing characteristics due to the distribution of the plasma sheath due to the electric field is corrected by controlling the gas flow of the reaction gas, and the variation in the distribution of the plasma sheath still exists. is not.

JP 2000-315676 A (Page 4, FIG. 1, FIG. 2)

  Normally, the cathode electrode surface is assumed to be so large that the outermost edge of the electrode is negligible, and when high-frequency power is applied to the center of the cathode electrode surface, the electric field generated on the cathode electrode surface is the highest at the point of application and goes outward to the cathode electrode. The distribution gradually decreases, and the plasma processing characteristics of the substrate to be processed are also affected by this distribution. The plasma sheath generated on the surface of the substrate to be processed is generated according to the electric field distribution on the cathode electrode, but actually does not always coincide. Because, usually, the dimension of the cathode electrode surface is designed to be somewhat larger with respect to the substrate to be processed, and the processing substrate is mounted on the cathode electrode, or the dimension is somewhat larger with respect to the substrate to be processed. It is designed small and a processing substrate is mounted on its cathode electrode. Therefore, even if high-frequency power is uniformly applied to the cathode electrode surface to generate a uniform electric field on the cathode electrode surface, in the former case, the outer peripheral edge of the substrate to be processed is located inside the cathode electrode surface. And the latter is the opposite. In any case, the electric field generated at the peripheral edge of the substrate to be processed is in a state where it is impossible to avoid a change in shape due to the thickness of the substrate to be processed and a change in impedance due to the material of the substrate to be processed. This causes the electric field to be distorted, and the plasma sheath near the outer peripheral edge of the substrate to be processed extremely increases. Further, when the dimensions of the substrate to be processed and the dimensions of the cathode electrode surface are designed to be the same, the shape change and the impedance change become much more remarkable than in the above case. The plasma sheath near the periphery increases. For this reason, there is a problem in that the plasma processing characteristics are more greatly varied at the outer peripheral edge of the substrate to be processed than at the inner surface of the substrate, and uniform processing cannot be performed.

  Therefore, an object of the present invention is a plasma processing apparatus in which a processing substrate is provided on an application electrode side, which corrects distortion of an electric field at an edge portion and distortion of a plasma to provide uniform plasma processing characteristics in a substrate surface. Provided is a plasma processing apparatus that can be realized.

  The plasma processing apparatus of the present invention is a plasma processing apparatus characterized by providing a ring including the outer peripheral edge of the substrate to be processed. With such a configuration, it is possible to correct a change in shape due to the thickness of the substrate to be processed and a change in impedance due to the material of the substrate to be processed. In other words, in order to correct the electric field near the upper surface of the outer peripheral edge of the substrate, the upper surface of the outer peripheral edge of the substrate and the surface in the vertical direction of the outer peripheral edge of the substrate include the outermost peripheral portion of the substrate for the purpose of shielding or relaxing the electric field. The ring is provided as described above. Furthermore, when the ring is in direct contact with the substrate, the impedance of the substrate itself changes due to the contact of the ring, so the substrate must be processed to ensure a certain distance so that the substrate does not directly contact the ring. A clearance is provided between the substrate and the ring enclosing surface.

  With such a configuration, it is possible to generate a uniform electric field, and it is possible to suppress a phenomenon in which the plasma sheath near the processing target substrate is extremely increased at the outer peripheral portion, and to suppress the phenomenon that the plasma sheath near the processing target substrate outer peripheral portion increases. This suppresses the occurrence of variations in the plasma processing characteristics, and enables uniform processing.

  The plasma processing apparatus of the present invention can correct a shape change due to the thickness of the substrate to be processed and a change in impedance due to the material of the substrate to be processed by providing the ring enclosing the outer peripheral edge of the substrate to be processed, In addition, by providing a clearance between the substrate to be processed and the ring enclosing surface, it is possible to generate a uniform electric field and suppress the phenomenon that the plasma sheath near the outer peripheral edge of the substrate is extremely increased. As a result, it is possible to suppress the occurrence of variations in the plasma processing characteristics at the outer peripheral edge of the substrate to be processed, and to perform uniform plasma processing.

  Before describing the various embodiments of the present invention, various aspects of the invention will be described.

The plasma processing apparatus according to the first aspect of the present invention introduces a processing gas into a processing chamber, excites plasma in the processing chamber, and performs processing on a substrate to be processed mounted on a cathode electrode in the processing chamber. A plasma processing apparatus for performing plasma processing,
By providing a ring having a clearance between the inner peripheral surface and the upper surface of the substrate to be processed, the outer peripheral edge of the substrate to be processed being included in proximity to the outer peripheral portion of the substrate to be processed. By correcting the etching rate of the outer periphery of the processing substrate, it is possible to generate an electric field uniformly, and it is possible to prevent the plasma sheath near the outer peripheral edge of the processing substrate from being extremely increased and the plasma processing characteristics from being varied. This has the effect of suppressing and enabling uniform plasma processing.

  In the plasma processing apparatus according to a second aspect of the present invention, in the first aspect, the surface of the cathode electrode on which the substrate is to be processed is larger than the substrate to be processed, and the ring is provided on the cathode electrode. And, the cross-sectional shape of the ring, characterized in that it has an L-shaped in a direction that can include the outer peripheral edge of the substrate to be processed, it is possible to generate a uniform electric field, This has the effect of suppressing the occurrence of variations in the plasma processing characteristics at the peripheral edge of the substrate to be processed, and enabling uniform plasma processing.

  In the plasma processing apparatus according to a third aspect of the present invention, in the second aspect, the L-shaped ring has a clearance in an outward direction of the processing target substrate with respect to the outer peripheral edge of the processing target substrate. An outer surface covering portion that covers an outer surface of the outer peripheral edge of the substrate to be processed, and a clearance in a thickness direction of the substrate to be processed, with respect to an upper surface of the outer peripheral edge of the substrate to be processed. The substrate to be processed is divided into an upper surface covering portion that covers the upper surface of the outer peripheral edge portion. The divisional structure has an effect of simplifying manufacturing.

  The plasma processing apparatus according to a fourth aspect of the present invention is the plasma processing apparatus according to the first aspect, wherein a surface of the cathode electrode contacting the substrate to be processed is smaller than the substrate to be processed, and the ring is the substrate to be processed of the cathode electrode. It is installed outside the contact surface and on the cathode electrode, and the cross-sectional shape of the ring has a U-shape in a direction that can include the outer peripheral edge of the substrate to be processed, It has the same function as the invention described in the first aspect.

  In a plasma processing apparatus according to a fifth aspect of the present invention, in the fourth aspect, the U-shaped ring has a clearance in an outward direction of the substrate to be processed with respect to an outer peripheral edge of the substrate to be processed. And an outer surface covering portion that covers an outer surface of the outer peripheral edge of the substrate to be processed, and a clearance in a thickness direction of the substrate to be processed with respect to an upper surface of an outer peripheral edge of the substrate to be processed. The substrate is divided into an upper surface covering portion that covers the upper surface of the outer peripheral edge of the substrate to be processed, and has the same operation as the invention described in the fourth aspect.

  The plasma processing apparatus according to a sixth aspect of the present invention is the plasma processing apparatus according to the third or fifth aspect, wherein the upper surface covering portion is movable from the outer surface covering portion to the outer surface covering portion in the thickness direction. In this way, the substrate is mounted, and has an effect that the substrate to be processed can be transported by driving the above-described portion.

  The plasma processing apparatus according to a seventh aspect of the present invention is the plasma processing apparatus according to any one of the first to sixth aspects, wherein the region including the outer peripheral edge of the substrate to be processed is formed from the outer peripheral edge of the substrate to be processed. A region covering the inside of the upper surface of the substrate is approximately 3 mm or more and 10 mm or less, and the clearance with respect to the ring-containing surface and the upper surface of the substrate to be processed is approximately 0.1 mm or more and 0.5 mm or less. By providing the above clearance between the substrate and the ring, it is possible to generate an optimal and uniform electric field, and to prevent a change in impedance of the substrate itself due to contact between the substrate and the ring. .

  The plasma processing apparatus according to an eighth aspect of the present invention is the plasma processing apparatus according to any one of the first to seventh aspects, wherein an area of the ring from the outer peripheral edge of the processing target substrate to the inside of the upper surface of the processing target substrate is the ring. The upper surface of the ring has a taper in the thickness direction from the innermost edge of the ring to the outside of the ring with respect to the lower surface of the ring, so that a change in impedance due to a change in the shape of the ring thickness can be corrected. Has an action.

Next, various embodiments of the present invention will be described.
(1st Embodiment)
1A, 1B and 1C are views showing a plasma processing apparatus according to a first embodiment of the present invention.

  1A, 1B, and 1C, the mass flow controller 2 controls the flow rate in a vacuum chamber 1 as an example of a vacuum chamber or a processing chamber that is evacuated to a predetermined pressure and evacuated by an exhaust device 30 such as a vacuum pump. A reaction gas as an example of the processed gas can be supplied into the vacuum vessel 1 from a large number of ejection holes 4 provided in the rectangular anode electrode 3. High-frequency power can be applied from the high-frequency power supply 5 to the rectangular plate-shaped cathode electrode 6, impedance can be matched by a matching box 7 on the way, and can be supplied to the cathode electrode 6 in the vacuum vessel 1. A rectangular plate-shaped insulating member 20 is interposed between the vacuum vessel 1 and the cathode electrode 6, and the vacuum vessel 1 and the anode electrode 3 are grounded.

  In the first embodiment, as shown in FIG. 1B and FIG. 1C, the surface (upper surface) of the substrate to be processed of the cathode electrode 6 is opposed to the surface (lower surface) of the substrate 8 to be contacted with the cathode electrode. The ring 10a, which is large in size and is made of an insulator that is stable even in plasma, such as ceramic, Duracon (registered trademark), and quartz, has an outer peripheral edge substantially on the upper surface of the cathode electrode 6 (substrate mounting surface). It is installed in. The cross-sectional shape of the ring 10a is such that a portion having a dimension larger than the thickness of the substrate 8 to be processed functions as a side surface covering portion that covers the outer side surface of the outer peripheral edge of the substrate 8 to be processed, and the remaining upper end 10a-1 has The projection protrudes toward the center along the substantially upper surface of the cathode electrode 6 so as to function as an upper surface covering portion that covers the upper surface of the outer peripheral edge of the substrate 8 to be processed, between the ring inner surface and the outer peripheral surface, and between the ring inner surface and the outer surface. It is L-shaped so that it can include the outer peripheral edge of the substrate 8 to be processed while providing clearances 41 and 42 between the peripheral side surfaces. Note that the clearance 42 may not be provided, and at least the clearance 41 may be provided between the inner surface of the ring 10a and the upper surface of the outer peripheral edge of the substrate 8 to be processed.

  It is preferable that the inner surface of the ring 10a is substantially parallel to the upper surface of the outer peripheral edge of the substrate 8 to be processed, and the inner surface of the ring 10a is substantially parallel to the side surface of the outer peripheral edge of the substrate 8 to be processed. It is preferable that

  According to the plasma processing apparatus having such a structure, an electric field is generated between the anode electrode 3 and the cathode electrode 6, and the reaction gas is turned into plasma by the electric field. The plasma etches the substrate 8 having a rectangular plate shape placed on the cathode electrode 6. In order to obtain in-plane uniformity of the substrate 8 to be processed, the plasma is applied on the cathode electrode 6 as described above. A clearance 41 is provided between the inner surface of the ring and at least the upper surface of the outer edge of the substrate 8, or preferably, between the inner surface of the ring and the upper surface of the outer edge. A rectangular ring 10a provided with clearances 41 and 42 between the outer peripheral edge and the side surface of the outer peripheral edge is provided to correct the etching rate in the vicinity of the outer peripheral edge of the substrate 8 to be processed. For this reason, a uniform electric field can be generated, and a phenomenon in which the plasma sheath near the outer peripheral edge of the processing target substrate 8 is extremely increased can be suppressed, and the occurrence of variation in plasma processing characteristics can be suppressed. It is possible to perform uniform plasma processing of the substrate 8 to be processed.

  In FIG. 1A, reference numeral 1000 denotes a control device, which includes an exhaust device 30, a high-frequency power supply 5, a mass flow controller 2, a substrate transfer mechanism, a door 15, a substrate transfer arm 14, a driving device 22, a substrate lifting and lowering driving device 21, which will be described later. Are respectively controlled.

As an example of the reaction gas, a mixed gas of Cl ₂ and BCl ₃ when the film to be etched on the substrate 8 to be processed is titanium or aluminum, a Cl ₂ gas when the film to be etched is silicon, and In the case of silicon, a CF-based gas such as CF ₄ is used. Further, as an example, the size of the substrate 8 to be processed is 550 mm × 670 mm, the pressure is 15 Pa to 3 Pa depending on the type of the film to be etched, the high frequency applied to the cathode electrode 6 from the high frequency power supply 5 is 13.56 MHz, and the power is It is 1000W-3000W. The power per unit area is 0.00271 to 0.00814 W / mm ² .

(2nd Embodiment)
FIG. 2A is a diagram illustrating a plasma processing apparatus according to a second embodiment of the present invention, in which the vicinity of the outer peripheral portion of the substrate 8 to be processed is enlarged. The second embodiment differs from the first embodiment in the plasma processing apparatus of FIG. 1A in the following points. That is, the size of the processing substrate contact surface 6a from which the central portion of the cathode electrode 6A protrudes upward is relatively smaller than the size of the cathode electrode contact surface of the processing substrate 8, and the rectangular ring 10b The ring 10b is disposed substantially outside the processing substrate contact surface 6a of the cathode electrode 6A, and the cross-sectional shape of the ring 10b is substantially along the processing substrate contact surface 6a of the cathode electrode 6A. 2 protrudes toward the center to provide clearance between the ring-containing surface and the upper surface of the outer peripheral edge of the substrate 8 to be processed, between the ring-containing surface and the outer peripheral side surface, and between the ring-containing surface and the lower surface of the outer peripheral edge. The U-shape is a direction in which the outer peripheral edge of the substrate 8 to be processed can be included while providing 41, 42, and 43, respectively. The upper end 10b-1 of the ring 10b projects more toward the center than the lower end 10b-2. The upper end 10b-1 of the ring 10b covers the upper surface of the outer peripheral edge of the substrate 8 to be processed, and the lower end 10b-2 covers the upper surface of the outer peripheral edge of the substrate 8 to be processed. 8 so as to cover the outer surface of the outer peripheral edge.

  It is preferable that the inner surface of the ring 10b and the upper surface of the outer peripheral edge of the substrate 8 be substantially parallel to each other, and that the inner surface of the ring 10b and the side surface of the outer edge of the substrate 8 be substantially parallel. It is preferable that the inner surface of the ring 10 b and the lower surface of the outer peripheral edge of the substrate 8 be substantially parallel to each other.

  On the other hand, FIGS. 2B and 2C are modified examples of the second embodiment. The difference from FIG. 2A is that there is no clearance on the lower surface side of the outer peripheral edge of the substrate 8 to be processed. Identical. That is, the cross-sectional shape of the ring 10b is such that the upper end portion 10b-1 and the lower end portion 10b-2 protrude toward the center substantially along the substrate-contacting surface 6a of the cathode electrode 6A, and It has a U-shape in a direction in which the outer peripheral edge of the substrate 8 can be included while providing clearances 41 and 42 between the upper surface of the peripheral edge and between the inner surface of the ring and the side surface of the outer peripheral edge. Assuming that the amount of projection of the processing substrate contact surface 6a-1 of the cathode electrode 6A-1 and the thickness of the lower end 10b-2 of the ring 10b are substantially the same, the lower surface of the outer peripheral edge of the processing substrate 8 is Since the electrode 6A-1 is placed over the substrate contact surface 6a-1 of the electrode 6A-1 and the lower end 10b-2 of the ring 10b, there is no clearance on the lower surface side of the outer peripheral edge of the substrate 8 to be processed.

2A and 2B to 2C, a uniform electric field can be generated, and a phenomenon in which the plasma sheath near the outer peripheral portion of the substrate 8 is extremely increased can be suppressed. Variations in plasma processing characteristics at the outer peripheral edge of the processing substrate 8 are suppressed, and uniform plasma processing can be performed.

(Third embodiment)
FIG. 3A is a diagram illustrating a plasma processing apparatus according to a third embodiment of the present invention, in which the vicinity of the outer peripheral edge of the substrate is enlarged. FIG. 3A shows that the L-shaped ring 10a of FIGS. 1A to 1C has a thickness greater than the thickness of the substrate 8 to be processed, and An outer surface covering portion 10c having a clearance 42 in the outer direction; and a projection protruding toward the center side from the outer surface covering portion 10c, and in a thickness direction of the substrate 8 with respect to an upper surface of an outer peripheral edge of the substrate 8 to be processed. It is configured as a ring 10g having a structure provided on the cathode electrode 6 so as to be divisible into an upper surface covering portion 10d having a clearance 41. The upper surface covering portion 10d of the ring 10g covers the upper surface of the outer peripheral edge of the substrate 8 to be processed, and the outer surface covering portion 10c covers the outer peripheral surface of the outer peripheral edge of the substrate 8 to be processed.

  FIG. 3B is a modification of the third embodiment. The U-shaped ring 10b of FIG. 2A has a thickness larger than the thickness of the substrate 8 to be processed, and On the other hand, an outer surface and a lower surface covering portion 10e having clearances 42 and 43 in both an outer direction and a lower surface side direction of the substrate 8 to be processed, and projecting toward the center side from the outer surface and the lower surface covering portion 10e, and The ring 10h has a structure provided on the cathode electrode 6A so as to be dividable into an upper surface covering portion 10f having a clearance 41 in the thickness direction of the substrate 8 to be processed with respect to the upper surface of the outer peripheral edge of the substrate 8. . The upper surface covering portion 10f of the ring 10h covers the upper surface of the outer peripheral edge of the substrate 8 to be processed, and the outer surface and the lower surface covering portion 10e cover the outer surface and the lower surface of the outer peripheral edge of the substrate 8 to be processed.

  3A and 3B, it is possible to generate a uniform electric field and to suppress a phenomenon in which the plasma sheath near the outer peripheral edge of the substrate 8 is extremely increased. Variations in the plasma processing characteristics at the outer peripheral edge of No. 8 are suppressed, and uniform plasma processing can be performed.

  Further, the splitting structure simplifies the manufacture, and the upper surface covering portion 10d or 10f having a clearance in the thickness direction of the processing target substrate 8 with respect to the upper surface of the outer peripheral edge portion of the processing target substrate 8 is formed as shown in FIG. 4B, the substrate 8 to be processed can be transferred by being driven in the vacuum vessel 1 by a driving mechanism as shown in FIG. 4B.

  FIG. 4A and FIG. 4B are views showing an example of a substrate transport mechanism that makes substrate transport possible. Here, as shown in FIG. 3B, a ring 10h that divides the outer surface and lower surface covered portion 10e and the upper surface covered portion 10f is connected to the cathode electrode 6A- having the processed substrate contact surface 6a-1 in FIG. 2A. The case in which there is no clearance 43 on the lower surface side when placed on No. 1 will be described.

  First, when the substrate 8 to be processed is placed on the cathode electrode 6A-1 in the vacuum vessel 1, four support bars 13 are attached along the rectangular short side of the ring 10h. 10f is raised by the ring lifting unit 11 which is an example of the driving mechanism. Each ring elevating unit 11 includes a driving device 22 such as a piston or a motor, and an abutting plate 24 having an L-shaped cross section connected to an upper end of a rod 23 driven by the driving device 22. The contact plate 24 is moved up and down by driving. When the abutment plate 24 is raised by the driving device 22, at the same time, the upper surface covering portion 10f of the ring 10h is substantially raised by abutting and lifting four support bars 13 along the rectangular short side of the ring 10h. In parallel, it is raised from the mounting position indicated by the solid line in FIG. 4B to the upper end position indicated by the dashed line.

  Next, with the substrate 8 to be processed placed on the U-shaped substrate transfer arm 14 at the retreat position II, the substrate transfer arm 14 passes through a pre-opened door 15 from a preparation room adjacent to the vacuum vessel 1, The substrate transfer arm 14 enters the vacuum vessel 1 in a state where the upper surface covering portion 10f of the ring 10h is located at the upper end position shown by the dashed line, and the space between the upper surface covering portion 10f of the ring 10h and the cathode electrode 6A-1. The substrate transfer arm 14 is inserted to the insertion position I.

  Next, for example, by driving the substrate lifting / lowering driving device 21 such as four pistons, the four substrate lifting / lowering pins 12 are raised from the lower end position of the solid line to the upper end position of the dashed line. The substrate 8 is lifted from the substrate transfer arm 14.

  Thereafter, the substrate transfer arm 14 moves out of the vacuum vessel 1, and the door 15 is closed.

  Thereafter, the substrate elevating pins 12 are lowered by the driving of the substrate elevating driving device 21, and the substrate 8 to be processed is placed on the cathode electrode 6 </ b> A- 1. Finally, the driving device 22 removes the upper surface covering portion 10 f of the ring 10 h. By lowering, the outer peripheral edge of the target substrate 8 can be covered by the upper surface covering portion 10f of the ring 10h.

  After the plasma processing is completed, the operation is reversed.

  That is, the upper surface covering portion 10f of the ring 10h covering the outer peripheral edge of the substrate 8 is raised to the upper end position by the driving device 22.

  Next, the substrate lifting pins 12 are moved up from the lower end position of the solid line to the upper end position of the alternate long and short dash line by the driving of the substrate lifting / lowering drive device 21 to lift the substrate 8 on the cathode electrode 6A-1 from the cathode electrode 6A-1. .

  Next, from the preparation chamber adjacent to the vacuum chamber 1, the substrate transfer arm 14 passes through the door 15 which has been opened in advance, enters the vacuum chamber 1, and moves between the lifted substrate 8 and the cathode electrode 6A-1. To the insertion position I.

  Next, the substrate elevating pins 12 move down to place the substrate 8 on the substrate transfer arm 14, and the substrate elevating pins 12 move down to the lower end position.

  Next, the substrate transfer arm 14 on which the substrate to be processed 8 is mounted moves outside the vacuum vessel 1 and the door 15 is closed.

4A and 4B, for simplification, the mass flow controller 2, the anode electrode 3, the gas ejection hole 4, the high frequency power supply 5, the matching box 7, and the like in FIG. 1A are omitted.

(Fourth embodiment)
FIG. 5 is a view showing a plasma processing apparatus according to a fourth embodiment of the present invention, in which the vicinity of the outer peripheral edge of the substrate 8 to be processed is enlarged by taking the second embodiment of FIG. 2A as an example. In the fourth embodiment, the distance between the clearances 41 and 42 in the second embodiment is specified, and the outer peripheral edge of the processing target substrate 8 when viewed directly from the upper surface of the processing target substrate 8 to the lower surface of the processing target substrate 8. The area D covering from the surface to the inside (center side) of the upper surface of the substrate 8 to be processed is about 1 mm or more and 10 mm or less, and the area between the ring inclusion surface and the upper surface of the outer peripheral edge of the substrate 8 to be processed is characterized. The distances d1 and d2 between the clearances 41 and between the ring and the inner surface of the ring and the outer peripheral edge of the substrate to be processed 8 are each about 0.1 mm or more and 1.0 mm or less. In any case, by having these distances, it is possible to optimally generate a uniform electric field, and it is possible to suppress a phenomenon in which the plasma sheath near the outer peripheral portion of the substrate 8 is extremely increased. . Note that if the thickness d3 of the inner edge of the upper end 10b-1 of the ring 10b is 3 mm or less, the distortion of the plasma sheath due to the thickness of the ring 10b can be ignored.

With such a dimensional configuration, variation in plasma processing characteristics at the outer peripheral edge of the substrate 8 to be processed can be more reliably suppressed, and more uniform plasma processing can be performed.

(Fifth embodiment)
FIG. 6 is a view showing a plasma processing apparatus according to a fifth embodiment of the present invention, in which the vicinity of the outer peripheral portion of the substrate 8 to be processed is enlarged using the second embodiment of FIG. 2A as an example. When viewed directly from the upper surface of the substrate 8 to the lower surface of the substrate 8, the upper surface covering portion 10 k of the ring 10 j covering from the outer peripheral edge of the substrate 8 to the inside of the upper surface of the substrate 8 is covered with the upper surface. With respect to the lower surface of the portion 10k, the upper surface of the upper surface covering portion 10k has a taper in the thickness direction so that the thickness increases from the innermost edge of the upper surface covering portion 10k to the outside of the upper surface covering portion 10k. Usually, the material forming the ring 10j is desirably an insulator that is stable even in plasma, such as ceramic, Duracon (registered trademark), and quartz, but these are brittle materials. Therefore, when the thickness d3 of the inner edge of the upper surface covering portion 10k is set to 3 mm or less, there is a very high possibility that the ring 10j will be damaged at the time of maintenance, attachment and detachment, etc. in consideration of actual use. To ensure the thickness. However, by making the shape tapered in the thickness direction as described above, it is possible to correct a change in impedance due to a change in the shape of the thickness of the ring 10j, and it is possible to generate an optimal and uniform electric field. Thus, a phenomenon in which the plasma sheath near the outer peripheral edge of the substrate 8 is extremely increased can be suppressed. For this reason, variations in plasma processing characteristics at the outer peripheral edge of the substrate 8 to be processed can be suppressed, and uniform plasma processing can be performed. The taper angle θ of the upper surface covering portion 10k of the ring 10j is desirably 10 ° to 30 ° in consideration of the strength of the inner edge of the upper surface covering portion 10k.

  FIG. 7A shows a case where a silicon nitride film substrate is etched in an Ar gas using a 550 mm × 670 mm substrate dry etching apparatus for a liquid crystal in a plasma processing apparatus to which the present invention is not applied. : 1200 sccm, pressure: 0.5 Pa, applied power: 4500 W). FIG. 7B shows a case where a silicon nitride film substrate is etched in an Ar gas using a 550 mm × 670 mm substrate-use liquid crystal dry etching apparatus in the plasma processing apparatus shown in the first embodiment of the present invention (as processing conditions). Indicates an etching rate of Ar gas: 1200 sccm, pressure: 0.5 Pa, applied power: 4500 W). When the silicon nitride film is etched in Ar gas, it is almost ionic etching, which is equivalent to measuring the sheath distribution on the surface of the substrate 8 to be processed.

  As a result, in FIG. 7A to which the present invention is not applied, while the etching rate of the outer peripheral edge of the substrate 8 to be processed is extremely increased, the plasma processing apparatus according to the first embodiment of the present invention is not used. In FIG. 7B used, it can be confirmed that the etching rate at the outer peripheral edge of the substrate 8 to be processed is suppressed.

  Therefore, according to the plasma processing apparatus according to the various embodiments of the present invention, it is possible to generate an electric field more uniformly than in the conventional example, and the plasma sheath near the outer peripheral edge of the substrate to be processed is formed. Extremely large phenomena can be suppressed. From this, it was proved that variation in plasma processing characteristics at the outer peripheral edge of the substrate to be processed was suppressed, and uniform plasma processing became possible.

  Note that by appropriately combining any of the various embodiments described above, the effects of the respective embodiments can be achieved.

FIG. 2 is a partial cross-sectional side view illustrating the entire plasma processing apparatus according to the first embodiment of the present invention. FIG. 2 is a plan view showing a ring of the plasma processing apparatus according to the first embodiment of the present invention. FIG. 1B is a partially enlarged side view showing a ring, a cathode electrode, and the like of the plasma processing apparatus according to the first embodiment of the present invention, as viewed from the direction of arrow A in FIG. 1B. It is a partial section enlarged side view showing a ring, a cathode electrode, and the like of a plasma processing apparatus according to a second embodiment of the present invention. FIG. 11 is a plan view showing a ring of a plasma processing apparatus according to a modification of the second embodiment of the present invention. FIG. 4 is a partially enlarged side view showing a ring, a cathode electrode, and the like of a plasma processing apparatus according to a modification of the second embodiment of the present invention, as viewed from the direction of arrow B in FIG. 2B. It is a partial section enlarged side view showing a ring, a cathode electrode, and the like of a plasma processing apparatus according to a third embodiment of the present invention. FIG. 11 is an enlarged partial cross-sectional side view showing a ring, a cathode electrode, and the like of a plasma processing apparatus according to a modification of the third embodiment of the present invention. It is a top view for explaining the state where a substrate is conveyed by the substrate conveyance mechanism in the plasma processing device concerning the above-mentioned modification of a 3rd embodiment of the present invention. FIG. 11 is an enlarged partial cross-sectional side view for explaining a state in which a substrate is transported by a substrate transport mechanism in a plasma processing apparatus according to a modification of the third embodiment of the present invention. It is a partial section enlarged side view showing a ring, a cathode electrode, and the like of a plasma processing apparatus according to a fourth embodiment of the present invention. It is a partial section enlarged side view showing a ring, a cathode electrode, etc. of a plasma processing device concerning a 5th embodiment of the present invention. 4 is a graph showing an etching rate when a silicon nitride film substrate is etched in Ar gas using a 550 mm × 670 mm liquid crystal dry etching apparatus for a substrate as a plasma processing apparatus to which the present invention is not applied. 4 is a graph showing an etching rate when a silicon nitride film substrate is etched in an Ar gas using a 550 mm × 670 mm substrate liquid crystal dry etching apparatus as the plasma processing apparatus according to the first embodiment of the present invention. It is a partial cross-sectional side view showing a conventional plasma processing apparatus. It is a perspective view which shows the conventional ring.

Explanation of reference numerals

DESCRIPTION OF SYMBOLS 1 Vacuum container 2 Mass flow controller 3 Anode electrode 4 Gas ejection hole 5 High frequency power supply 6, 6A, 6A-1 Cathode electrode 6a, 6a-1 Processing substrate contact surface 7 Matching box 8 Processing substrate 10a, 10b, 10g, 10h , 10j ring 10b-1 upper end portion 10b-2 lower end portion 10c outer surface covering portion 10d, 10f, 10k upper surface covering portion 10e outer surface and lower surface covering portion 11 ring elevating unit 12 substrate elevating pin 13 support bar 14 substrate transport arm 15 door Reference Signs List 20 Insulating member 21 Substrate lifting drive 22 Drive 30 Exhaust 41, 42, 43 Clearance 1000 Control

Claims (8)

A plasma processing apparatus for introducing a processing gas into a processing chamber, exciting plasma in the processing chamber, and performing plasma processing on a substrate to be processed mounted on a cathode electrode in the processing chamber,
A ring is provided in the vicinity of the outer peripheral edge of the substrate to be processed, which encloses the outer peripheral edge of the substrate to be processed, and has a clearance between its internal surface and the upper surface of the substrate to be processed. Plasma processing apparatus.   The substrate mounting surface of the cathode electrode is large with respect to the substrate to be processed, the ring is provided on the cathode electrode, and the cross-sectional shape of the ring corresponds to the outer peripheral edge of the substrate to be processed. The plasma processing apparatus according to claim 1, wherein the plasma processing apparatus has an L-shape in a direction that can be included.   The L-shaped ring has an outer surface covering the outer peripheral edge of the substrate to be processed and having a clearance in an outward direction of the substrate to cover the outer surface of the outer peripheral edge of the substrate to be processed. A portion and an upper surface covering portion having a clearance in a thickness direction of the substrate to be processed and covering the upper surface of the outer peripheral portion of the substrate to be processed, with respect to the upper surface of the outer peripheral portion of the substrate to be processed. The plasma processing apparatus according to claim 2, wherein the plasma processing apparatus is divided.   A substrate contact surface of the cathode electrode to be processed is smaller than the substrate to be processed; the ring is installed outside the substrate contact surface of the cathode electrode and on the cathode electrode; and a cross-sectional shape of the ring 2. The plasma processing apparatus according to claim 1, wherein the substrate has a U-shape in a direction that can include an outer peripheral portion of the substrate to be processed.   The U-shaped ring has an outer surface covering the outer peripheral surface of the substrate to be processed, having a clearance in an outward direction of the substrate to be processed with respect to the outer peripheral edge of the substrate to be processed. And a top surface covering portion having a clearance in the thickness direction of the substrate to be processed and covering the upper surface of the outer peripheral portion of the substrate with respect to the upper surface of the outer peripheral portion of the substrate to be processed. The plasma processing apparatus according to claim 4, wherein the plasma processing apparatus is used.   The said upper surface covering part is mounted on the said outer surface covering part so that the said upper surface covering part can move in the said thickness direction from the said outer surface covering part, The said Claim 3 or 5 characterized by the above-mentioned. Plasma processing equipment.   The region including the outer peripheral edge of the substrate to be processed, the region covering from the outer peripheral edge of the substrate to be processed to the inner side of the upper surface of the substrate to be processed is approximately 3 mm or more and 10 mm or less. The plasma processing apparatus according to any one of claims 1 to 6, wherein a clearance between the upper surface of the substrate to be processed and the substrate is approximately 0.1 mm or more and 0.5 mm or less. The area to cover from the outer peripheral edge of the substrate to be processed to the inside of the upper surface of the substrate to be processed, the upper surface of the ring relative to the lower surface of the ring, from the innermost edge of the ring to the outside of the ring, The plasma processing apparatus according to claim 1, wherein the plasma processing apparatus has a taper in a thickness direction.

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