JP5227197B2 - Focus ring and plasma processing apparatus - Google Patents

Description

  The present invention relates to a focus ring attached to a peripheral portion of an electrode, and a plasma processing apparatus including an electrode to which the focus ring is attached.

  A plasma processing apparatus is used to perform a process such as etching on a target object such as a flat panel display substrate (hereinafter referred to as an FPD glass substrate).

  For example, as described in Patent Document 1, the plasma processing apparatus includes a processing chamber that performs plasma processing on a target object, and an upper electrode that faces each other, and a mounting for mounting the target object in the processing chamber. A lower electrode also serving as a mounting table is provided. A high frequency is applied between the upper electrode and the lower electrode, and plasma is generated in a processing space between the upper electrode and the lower electrode. A focus ring for concentrating the high-frequency electric field above the object to be processed is attached to the peripheral portion of the lower electrode. The focus ring is made of ceramics, generally an alumina sintered body. The alumina sintered body has an advantage that it is excellent in plasma resistance and hardly corrodes.

JP 2003-115476 A

  However, the alumina sintered body has a high relative dielectric constant of 9 to 10 and has a relatively low shielding property against a high frequency electric field. For this reason, if the application of the high frequency electric field is repeated, the surface of the focus ring is scraped off and becomes a particle source.

  An object of the present invention is to provide a focus ring excellent in both plasma resistance and shielding performance against a high-frequency electric field, and a plasma processing apparatus including the focus ring.

In order to solve the above problem, a focus ring according to the first aspect of the present invention is arranged as a mounting table for mounting the object to be processed into the processing chamber for performing a plasma treatment, and the convex portion, the convex A focus that is mounted on the flange portion of the electrode having a flange portion around the portion, surrounding the periphery of the convex portion, and concentrates a high-frequency electric field on the object to be processed placed on the mounting table. a ring, having a multilayer structure formed by laminating a plurality of dielectric having a dielectric constant different, the one of the plurality of dielectric having a dielectric constant different, the said electrodes having a lower dielectric constant low-k dielectric A plasma-resistant dielectric disposed on the flange portion side and having a dielectric constant higher than that of the low-dielectric-constant dielectric and having higher plasma resistance than the low-dielectric-constant dielectric is treated in the processing space of the processing chamber. place on a side, the low-k dielectric and Ki耐plasma dielectric respectively a split type that connects a plurality of divided members, the position of the joint of the divided members is different the low-k dielectric and said plasma resistance dielectric.

A plasma processing apparatus according to a second aspect of the present invention includes a processing chamber for performing plasma processing on an object to be processed, an upper electrode disposed in the processing chamber, and a position facing the upper electrode in the processing chamber. wherein arranged as mounting table for mounting the object to be processed, it comprises a convex portion, and a lower electrode and a flange portion around the convex portion, on the flange portion of the lower electrode Further, the focus ring according to the first aspect is attached to surround the periphery of the convex portion .

  According to the present invention, it is possible to provide a focus ring excellent in both plasma resistance and shielding performance against a high-frequency electric field, and a plasma processing apparatus including the focus ring.

Sectional drawing which shows roughly an example of the plasma processing apparatus which concerns on 1st Embodiment Cross-sectional view of the focus ring and its surroundings 3A is a perspective view showing an example of a focus ring according to the second embodiment, and FIG. 3B is a cross-sectional view taken along line 3B-3B in FIG. 3A. The perspective view which showed the modification of a joint The perspective view at the time of applying to the focus ring which concerns on 2nd Embodiment the joint which concerns on a modification Sectional drawing which showed an example of the focus ring which concerns on 3rd Embodiment Sectional drawing which showed the other example of the focus ring which concerns on 3rd Embodiment Sectional drawing which showed another example of the focus ring which concerns on 3rd Embodiment Sectional drawing which showed an example of the focus ring which concerns on 4th Embodiment Sectional drawing which showed an example of the focus ring which concerns on 5th Embodiment Sectional drawing which showed the other example of the focus ring which concerns on 5th Embodiment Sectional view showing a focus ring according to a reference example Sectional drawing which showed an example of the focus ring which concerns on 6th Embodiment Sectional drawing which showed the other example of the focus ring which concerns on 6th Embodiment Sectional drawing which showed the other example of the focus ring which concerns on 6th Embodiment Sectional drawing which showed the other example of the focus ring which concerns on 6th Embodiment Sectional drawing which showed the 1st example of the focus ring which concerns on 7th Embodiment Sectional drawing which showed the 2nd example of the focus ring which concerns on 7th Embodiment Sectional drawing which showed the 3rd example of the focus ring which concerns on 7th Embodiment

  Embodiments of the present invention will be described below with reference to the drawings. Throughout the drawings to be referred to, the same parts are denoted by the same reference numerals.

(First embodiment)
FIG. 1 is a sectional view schematically showing an example of a plasma processing apparatus according to the first embodiment of the present invention.

  The plasma processing apparatus 1 shown in FIG. 1 is an example of an apparatus that performs a predetermined process on the glass substrate G for FPD, and is configured as a capacitively coupled parallel plate plasma etching apparatus. Here, as FPD, a liquid crystal display (LCD), an electroluminescence (Electro Luminescence; EL) display, a plasma display panel (PDP), etc. are illustrated.

  The plasma processing apparatus 1 has a processing chamber (processing chamber) 2 formed into a rectangular tube shape made of aluminum, for example, whose surface is anodized (anodized). A mounting table 3 for mounting a glass substrate G as a substrate to be processed is provided at the bottom of the processing chamber 2.

  The mounting table 3 is supported on the bottom of the processing chamber 2 via an insulating member 4. The mounting table 3 includes a convex portion 5a and a conductive substrate 5 having a flange portion 5b around the convex portion 5a. A frame-shaped focus ring 6 surrounding the periphery of the convex portion 5a is provided on the peripheral portion of the base material 5, in this example, the flange portion 5b, and further, the periphery of the base material 5, in this example, the flange portion. On the side surface of 5b, an insulating ring 7 surrounding the periphery of the flange portion 5b is provided. The surface of the substrate 5 is covered with an insulating coating 8, for example, alumina spraying or alumite.

  A power supply line 12 for supplying high-frequency power is connected to the base material 5, and a matching unit 13 and a high-frequency power source 14 are connected to the power supply line 12. From the high frequency power supply 14, for example, high frequency power of 13.56 MHz is supplied to the base material 5 of the mounting table 3. Thereby, the base material 5 functions as a lower electrode.

  Above the mounting table 3, a shower head 20 that functions as an upper electrode is provided in parallel with the mounting table 3. The shower head 20 is supported on the upper part of the processing chamber 2, has an internal space 21 inside, and has a plurality of discharge holes 22 for discharging processing gas on the surface facing the mounting table 3. The shower head 20 is grounded and constitutes a pair of parallel plate electrodes together with the mounting table 3 functioning as a lower electrode.

A gas inlet 24 is provided on the upper surface of the shower head 20, and a processing gas supply pipe 25 is connected to the gas inlet 24, and the processing gas supply pipe 25 is connected to a processing gas supply source 28. Yes. Further, an opening / closing valve 26 and a mass flow controller 27 are interposed in the processing gas supply pipe 25. A processing gas for plasma processing, for example, plasma etching, is supplied from the processing gas supply source 28. As the processing gas, a gas usually used in this field, such as a halogen-based gas, an O ₂ gas, or an Ar gas, can be used.

  An exhaust pipe 29 is formed at the bottom of the processing chamber 2, and an exhaust device 30 is connected to the exhaust pipe 29. The exhaust device 30 includes a vacuum pump such as a turbo molecular pump, and is configured so that the processing chamber 2 can be evacuated to a predetermined reduced pressure atmosphere.

  A substrate loading / unloading port 31 is provided on the side wall of the processing chamber 2, and the substrate loading / unloading port 31 can be opened and closed by a gate valve 32. And the glass substrate G for FPD is carried in / out by the conveyance apparatus (not shown) in the state which opened this gate valve 32. FIG.

  FIG. 2A is an enlarged cross-sectional view of the focus ring 6 and its periphery.

  As shown in FIG. 2A, the focus ring 6 of this example is a multilayer structure focus ring. The multi-layer structure focus ring 6 is mounted on the flange portion 5 b and the insulating ring 7. In this example, the insulating ring 7 is a multiple insulating ring in which an inner ring 7a and an outer ring 7b are combined. In this example, the multi-layer structure focus ring 6 is a two-layer structure focus ring in which an upper dielectric and a lower dielectric are stacked.

  Further, in this example, the lower dielectric disposed on the flange portion 5b side is a low dielectric constant dielectric 6a having a low dielectric constant, and the upper dielectric disposed on the processing space side of the processing chamber 2 has a dielectric constant of The plasma-resistant dielectric 6b is equal to or higher than the dielectric constant of the low dielectric constant dielectric 6a and has higher plasma resistance than the low dielectric constant dielectric 6a.

  Examples of the plasma-resistant dielectric 6b include plasma-resistant dielectric ceramics such as an alumina sintered body, a porous alumina sintered body, and a yttria sintered body. The relative dielectric constant of the alumina sintered body is about 9-10. The relative dielectric constant of the porous alumina sintered body is lower than about 9 to 10, and is about 3 to 5 depending on the porosity. The relative permittivity of the yttria sintered body is about 11.

  Examples of the low dielectric constant dielectric 6a include quartz, porous ceramics, and fluororesin. The relative dielectric constant of quartz is about 3 to 4, the relative dielectric constant of porous ceramics such as porous alumina sintered body is about 3 to 5 as described above, and the relative dielectric constant of fluororesin such as tetrafluoroethylene resin. Is about 2.

  As an example of the combination, when an alumina sintered body is used for the plasma-resistant dielectric 6b, quartz, porous ceramics, or fluororesin can be used for the low dielectric constant dielectric 6a.

  Also, when a porous alumina sintered body is used for the plasma-resistant dielectric 6b, quartz, porous ceramics, or fluororesin can be used for the low dielectric constant dielectric 6a. In addition, when a porous ceramic, for example, a porous alumina sintered body is used for both the plasma-resistant dielectric 6b and the low dielectric constant dielectric 6a, the dielectric constant is the same. The dielectric constant may be the same for both the plasma-resistant dielectric 6b and the low dielectric constant dielectric 6a. However, when the same kind of porous ceramics is used, the porosity may be changed between the plasma-resistant dielectric 6b and the low dielectric constant dielectric 6a, for example. For example, the porosity of the plasma resistant dielectric 6b is set to 40%, and the porosity of the low dielectric constant dielectric 6a is set to 60%. When the porosity is changed in this way, for example, the plasma-resistant dielectric 6b has a low porosity, so that the plasma resistance is good, and the low-dielectric dielectric 6a has a high porosity, so the relative dielectric constant becomes small, The shielding property of the high frequency electric field can be improved.

  Further, as shown in FIG. 2B, when the height of the plasma-resistant dielectric 6b is made higher than the electrode surface and the thickness is increased, the shielding property can be further improved.

  In the case where only the shielding property is regarded as important, it is also possible to use a material having low plasma resistance, such as quartz, for the member indicated by reference numeral 6b.

  As described above, according to the focus ring 6 provided in the plasma processing apparatus 1 according to the first embodiment, the low dielectric constant dielectric 6a is disposed on the substrate 5 side, and the dielectric constant is the low dielectric constant dielectric 6a. A plasma-resistant dielectric 6b having a dielectric constant or higher and higher plasma resistance than the low-dielectric-constant dielectric 6a is disposed on the processing space side of the processing chamber 2. With this configuration, it is possible to obtain a focus ring excellent in both plasma resistance and shielding performance against a high-frequency electric field, and a plasma processing apparatus including the focus ring.

(Second Embodiment)
3A is a perspective view illustrating an example of a focus ring according to the second embodiment, and FIG. 3B is a cross-sectional view taken along line 3B-3B in FIG. 3A.

  As shown in FIGS. 3A and 3B, the focus ring 6 according to the second embodiment includes a low dielectric constant dielectric 6a and a plasma-resistant dielectric 6b, and a plurality of divided members 6a1 to 6a4 and 6b1 to 6b4. It is a divided type that is connected. The split type focus ring 6 is effective when the glass substrate for FPD becomes large and it is difficult to form the focus ring 6 integrally.

  Further, in this example, in the split type focus ring 6, the position of the joint 9 of the split members 6a1 to 6a4 and the position of the joint 10 of the split members 6b1 to 6b4 are made different. There is a clearance (gap) at the joint. During the plasma treatment, a high frequency is applied to the substrate 5. For this reason, in the split-type focus ring 6, abnormal discharge is likely to occur at the joint.

  On the other hand, in this example, the positions of the joints 9 and 10 are made different between the low dielectric constant dielectric 6a and the plasma resistant dielectric 6b. Thereby, there is no clearance extending straight from the surface of the base material 5 toward the space above the focus ring 6. Therefore, compared with a focus ring in which the positions of the joints 9 and 10 match between the low dielectric constant dielectric 6a and the plasma resistant dielectric 6b, the possibility of abnormal discharge can be reduced, and abnormal discharge resistant Can increase the sex.

  Further, as shown in FIGS. 4A and 4B, the joints 9 and 10 are formed in a stepped structure even when viewed from the surface (viewed from the Z-axis) or from the side (viewed from the X-axis). Abnormal discharge resistance on the side surface can be improved.

  Furthermore, as shown in FIG. 4C, even in the cross section along the line 4C-4C (cross section along the X-axis direction) in FIG. be able to.

  FIG. 5 shows a perspective view of an example in which the modification example of the joint shown in FIGS. 4A to 4C is applied to the focus ring according to the second embodiment.

  Although not shown, the staircase structure shown in FIGS. 4A to 4C may be obtained by dividing it into separate parts.

(Third embodiment)
FIG. 6 is a cross-sectional view showing an example of the focus ring according to the third embodiment, and FIG. 7 is a cross-sectional view showing another example of the focus ring according to the third embodiment.

  The low dielectric constant dielectric 6a of the focus ring 6 may be disposed on the base material 5 side. For this reason, for example, as shown in FIG. 6, the low dielectric constant dielectric 6a may be disposed from the upper surface of the flange portion 5b to the entire upper surface of the inner ring 7a, and as shown in FIG. Further, it may be disposed only on the upper surface of the flange portion 5b.

  However, in the case of the focus ring 6 shown in FIG. 7, the position of the boundary surface 41 between the inner ring 7a and the low dielectric constant dielectric 6a coincides with the edge 42 of the flange portion 5b. There is a clearance at the boundary surface 41. The edge 42 is a corner. Electric field concentration tends to occur at the corners. For this reason, the plasma that has entered from the joint of the focus ring 6 may cause abnormal discharge in the corner 42 through the boundary surface 41.

  When it is desired to reduce the possibility of such an abnormal discharge, a flange with a low dielectric constant dielectric 6a, such as the focus ring 6 shown in FIGS. 2A and 2B and the focus ring 6 shown in FIG. It is preferable to cover the edge 42 of the part 5b.

  Also, the focus ring 6 shown in FIG. 4 and the focus ring 6 shown in FIG. 2 are configured such that the outer surface 43 of the low dielectric constant dielectric 6a opposite to the convex portion 5a has a plasma-resistant dielectric. It differs in that it matches the outer surface 44 located on the opposite side of the convex portion 5a of the body 6b or whether the outer surface 43 is arranged between the outer surface 44 and the edge 42.

  The clearance also exists on the boundary surface between the focus ring 6 and the insulating ring 7. This clearance reaches the substrate 5. When plasma enters from such a clearance, abnormal discharge occurs in the substrate 5.

  In order to suppress such abnormal discharge of the base material 5, the clearance existing on the boundary surface between the focus ring 6 and the insulating ring 7 may be bent in a key shape or stepped shape. For this purpose, for example, the horizontal width d1 of the low dielectric constant dielectric 6a is wider than the horizontal width d2 of the flange portion 5b as in the focus ring 6 shown in FIG. The horizontal width of the plasma dielectric 6b, in particular, the horizontal width d3 on the bottom side is made narrower. Or, conversely, as shown in FIG. 8, the horizontal width d1 of the low dielectric constant dielectric 6a is made narrower than the horizontal width d2 of the flange portion 5a, so that it is effective even if the plasma penetration path is lengthened. There is. Or like the plasma-resistant dielectric 6b, the outer side surface 44 is processed in steps. Alternatively, by combining these, the clearance is bent in a key shape or stepped shape at the boundary surface between the focus ring 6 and the insulating ring 7. By bending the clearance, it is possible to prevent the plasma from entering or lengthen the intrusion path, and to suppress abnormal discharge to the substrate 5.

  Further, for example, in the focus ring 6 shown in FIG. 2 described above, the outer surface 43 of the low dielectric constant dielectric 6a is not processed in a stepped manner, but like the outer surface 44 of the plasma-resistant dielectric 6b, It may be processed into a staircase shape.

(Fourth embodiment)
FIG. 9 is a cross-sectional view showing an example of a focus ring according to the fourth embodiment.

  As shown in FIG. 9, the focus ring 6 according to the fourth embodiment differs from the focus ring 6 described in the first embodiment in that the side surface 45 of the convex portion 5a and the low dielectric constant dielectric 6a are A dielectric seal member 51 is further provided between the inner surface 46 located on the convex portion 5a side. An example of the dielectric seal member 51 is an O-ring.

  In the case where the low dielectric constant dielectric 6a is, for example, an integral type, the low dielectric constant dielectric 6a is fitted to the convex portion 5a and attached to the substrate 5. A clearance is required between the low dielectric constant dielectric 6a and the convex portion 5a. A narrower clearance is better for suppressing abnormal discharge, for example. However, if a low-k dielectric material 6a is made of an easily chipped material (brittle material) such as quartz while the clearance is narrowed, the low-k dielectric material 6a is damaged during handling (assembly). There is a possibility that.

  When it is desired to reduce the damage of the low dielectric constant dielectric 6a during the handling, the clearance between the low dielectric constant dielectric 6a and the convex portion 5a as in the focus ring 6 according to the fourth embodiment. To widen. And it is good to attach the dielectric seal member 51 to a clearance part, and to eliminate a clearance gap.

  In this example, a dielectric spacer 52 is further provided between the dielectric seal member 51 and the flange portion 5b.

  The advantage of providing the dielectric spacer 52 is that the dielectric seal member 51, for example, the O-ring alone, fills the clearance with the dielectric even when the clearance between the inner surface 46 and the convex portion 5a cannot be sealed. In order to prevent damage to the low dielectric constant dielectric 6a, the clearance can be filled with a dielectric even when the clearance between the inner surface 46 and the convex portion 5a is made wider.

  Examples of the dielectric seal member 51 include fluororubber. For example, Viton (registered trademark) can be preferably used as the fluororubber. The relative permittivity of fluororubber, for example, the relative permittivity of Viton is about 2 to 2.5. If the dielectric seal member 51 has a dielectric constant equal to or lower than that of the plasma-resistant dielectric 6b, the shielding property of the high-frequency electric field is not impaired.

  An example of the dielectric spacer 52 can be a fluororesin. As the fluororesin, a tetrafluoroethylene resin or the like can be preferably used. The relative dielectric constant of the fluororesin, for example, the relative dielectric constant of the tetrafluoroethylene-based resin is about 2 as described in the first embodiment. By using the dielectric spacer 52 having a relative dielectric constant equal to or lower than that of the plasma-resistant dielectric 6b, the shielding property of the high-frequency electric field is not impaired as in the dielectric seal member 51.

  As described above, according to the focus ring 6 according to the fourth embodiment, the dielectric seal member 51 or the dielectric seal is provided between the side surface 45 of the convex portion 5a and the inner side surface 46 of the low dielectric constant dielectric 6a. By further including the member 51 and the dielectric spacer 52, the handling property (assembly property) of the plasma processing apparatus can be improved.

  In addition, since the handling property is good, it is easy to remove and attach the low dielectric constant dielectric 6a. This is effective for facilitating maintenance.

  Moreover, even when a low dielectric constant dielectric 6a, such as quartz, that is easily chipped is used, the clearance can be widened, so that damage to the low dielectric constant dielectric 6a can be suppressed.

  In this example, the case where the low dielectric constant dielectric 6a is integrated is described. However, even if the low dielectric constant dielectric 6a is a split type, the dielectric seal member 51 or the dielectric seal member is used. Of course, 51 and dielectric spacer 52 can be used.

(Fifth embodiment)
FIG. 10 is a sectional view showing an example of the focus ring according to the fifth embodiment, and FIG. 11 is a sectional view showing another example of the focus ring according to the fifth embodiment.

  As shown in FIG. 10, the focus ring 6 according to the fourth embodiment differs from the focus ring 6 described in the first embodiment on the surface of the plasma-resistant dielectric 6b facing the processing space. This is that the plasma resistant material is sprayed and the plasma resistant dielectric coating 61 is applied.

Examples of plasma resistant materials used for plasma resistant dielectric coating 61 and sprayed include yttrium oxide (eg, Y ₂ O ₃ ), yttrium fluoride (eg, YF ₃ ), aluminum oxide (eg, Al). ₂ O ₃ ).

  As described above, the plasma resistance of the focus ring 6 can be further improved by applying the plasma resistance dielectric coating 61 on the surface of the plasma resistance dielectric 6b facing the processing space.

  Further, when the plasma-resistant dielectric coating 61 is applied, it is possible to eliminate the plasma-resistant dielectric 6b and use only the low dielectric constant dielectric 6a, as shown in FIG. In this case, almost the entire focus ring 6 can be made of only a material having a low dielectric constant, for example, quartz, porous ceramics, or a fluororesin, and the dielectric constant of the focus ring 6 itself is low, thereby providing a shielding property against a high-frequency electric field. Can be increased.

(Sixth embodiment)
In the above embodiment, the low dielectric constant dielectric 6a is disposed on the substrate 5 side, and the plasma-resistant dielectric 6b is disposed on the processing space side of the processing chamber 2, so that as shown in FIG. Thus, the influence of the electric field Ev in the vertical direction from the bottom surface 47 of the convex portion 5a can be weakened, and the shielding property against the high frequency electric field can be improved. However, as a result of improving the shielding property and weakening the electric field Ev in the vertical direction, the electric field Ei in the oblique direction from the side surface 45 of the convex portion 5a is increased, and the focus ring 6 is locally scraped. 12, as indicated by reference numeral 67, there is a possibility that the portion where the electric field Ei in the oblique direction works most strongly is scraped. When it is desired to suppress such shaving, the focus ring according to the sixth embodiment is preferably used.

  FIG. 13 is a cross-sectional view showing an example of a focus ring according to the sixth embodiment, and FIGS. 14 to 16 are cross-sectional views showing other examples of the focus ring according to the sixth embodiment.

  As shown in FIG. 13, the focus ring 6 according to the sixth embodiment differs from the focus ring 6 described in the first embodiment in that a frame-shaped electric field shield is formed on the upper surface of the plasma-resistant dielectric 6b. The block member 71 is provided. The electric field shielding block member 71 is provided on a portion 67 where the electric field Ei in the oblique direction acts most strongly on the upper surface of the plasma-resistant dielectric 6b. In this example, the portion 67 exists above the bottom surface 47 of the convex portion 5a and at a position away from the peripheral edge of the glass substrate G on the upper surface of the plasma-resistant dielectric 6b.

  Thus, by providing the electric field shielding block member 71 on the portion 67 where the electric field Ei acts most strongly on the upper surface of the plasma resistant dielectric 6b, the thickness of the plasma resistant dielectric 6b on the portion 67 is increased. The thickness can be increased. The material of the electric field shielding block member 71 may be the same material as the plasma-resistant dielectric 6b.

  According to the focus ring 6 according to the sixth embodiment, by further providing the electric field shielding block member 71, the thickness of the plasma-resistant dielectric 6b can be increased and the electric field Ei in the oblique direction can be weakened. Is possible.

  Therefore, even when the electric field shielding property is enhanced by the low dielectric constant dielectric, it is possible to suppress the local abrasion of the focus ring 6, and both the plasma resistance and the shielding property against the high frequency electric field can be prevented. In addition to being excellent, it is possible to obtain a focus ring that is particularly improved in shielding performance against a high-frequency electric field and a plasma processing apparatus including the focus ring.

  Further, the electric field shielding block member 71 is partially provided in a frame shape on the portion 67 and in the vicinity thereof, and as shown in FIG. 14, covers the portion 67 and its vicinity to the outer edge of the focus ring 6 to form a frame shape. May be provided. In this case, it is possible to obtain an advantage that the electric field Ev in the vertical direction can be weakened as compared with the case where the electric field shielding block member 71 is partially provided.

  Further, as shown in FIG. 15, on the processing space side exposed surface 68 of the plasma-resistant dielectric 6b not covered with the electric field shielding block member 71 in the focus ring 6 shown in FIG. 14 (or FIG. 13). For example, the plasma-resistant dielectric coating 61 may be applied by thermal spraying.

  Further, as shown in FIG. 16, the plasma-resistant dielectric coating 61 may be further provided on the surface inside the electric field shielding block member 71 (on the glass substrate G side).

  An example of the material of the plasma resistant dielectric coating 61 may be the same material as described in the fifth embodiment.

  As described above, the plasma-resistant dielectric coating 61 is applied on the exposed surface 68, or the plasma-resistant dielectric coating 61 is applied on the exposed surface 68 and on the inner surface of the electric field shielding block member 71. The shielding property against the high frequency electric field of the focus ring 6 according to the embodiment can be further improved.

Further, the plasma resistant dielectric coating 61 is partially applied on the exposed surface 68 or on the exposed surface 68 and the inner surface of the electric field shielding block member 71, thereby focusing the plasma resistant dielectric coating 61. Compared with the case where it is applied over the entire surface of the ring 6, the amount of expensive plasma-resistant material used can be minimized, and both the plasma resistance and the shielding property against a high-frequency electric field are excellent. It is possible to obtain an advantage that a focus ring that further improves the shielding property against a high-frequency electric field can be obtained at a low cost.
(Seventh embodiment)
As in the sixth embodiment, the seventh embodiment relates to a focus ring that can weaken an electric field Ei in an oblique direction.

  As a method for weakening the electric field Ei in the oblique direction, in addition to the method of providing the electric field shielding block member 71, a method of devising the shape of the low dielectric constant dielectric 6a can be considered. The seventh embodiment is an example in which the shape of the low dielectric constant dielectric 6a is devised to weaken the electric field Ei in the oblique direction.

  FIG. 17 is a cross-sectional view showing a first example of a focus ring according to the seventh embodiment.

  As shown in FIG. 17, the focus ring 6 according to the first example is different from the focus ring 6 described in the first embodiment in that the thickness of the low dielectric constant dielectric 6a is from the outer periphery to the side surface of the convex portion 5a. It is that it becomes thick gradually toward 45.

  According to the first example, the thickness of the low dielectric constant dielectric 6a is gradually increased from the outer periphery toward the side surface 45 of the convex portion 5a, so that the side surface 45 of the convex portion 5a is formed of the low dielectric constant dielectric 6a. Can be used to coat more widely. In other words, the low dielectric constant dielectric 6a is interposed between the side surface 45 and the plasma-resistant dielectric 6b.

  Thus, by covering the side surface 45 with the low dielectric constant dielectric 6a widely, the electric field Ei in the oblique direction can be weakened, and the same advantages as in the sixth embodiment described above can be obtained.

  FIG. 18 is a cross-sectional view showing a second example of the focus ring according to the seventh embodiment.

  As shown in FIG. 18, the focus ring 6 according to the second example is different from the focus ring 6 according to the first example shown in FIG. 17 in that the thickness of the low dielectric constant dielectric 6a is the side surface of the convex portion 5a. In the vicinity of 45, it is thick in steps.

  Even in this case, the side surface 45 is widely covered with the low dielectric constant dielectric 6a, and the electric field Ei in the oblique direction can be weakened.

  In the second example shown in FIG. 18, the thickness of the low dielectric constant dielectric 6a is increased in one step. However, the thickness of the low dielectric constant dielectric 6a is increased from the outer periphery toward the side surface 45 of the convex portion 5a. The thickness may be increased stepwise.

  FIG. 19 is a cross-sectional view showing a third example of the focus ring according to the seventh embodiment.

  As shown in FIG. 19, the focus ring 6 according to the third example is different from the focus ring 6 according to the first example shown in FIG. 17 in that the lower portion of the side surface 45 of the convex portion 5a is recessed. In other words, the low dielectric constant dielectric 6a is formed in the portion.

  According to the third example, the low dielectric constant dielectric 6a is interposed between the lower portion of the side surface 45 of the convex portion 5a and the plasma-resistant dielectric 6b. For this reason, similarly to the focus ring 6 according to the first example, the electric field Ei in the oblique direction can be weakened, and the same advantages as those of the above-described sixth embodiment can be obtained.

  As mentioned above, although this invention was demonstrated by some embodiment, this invention is not limited to the said some embodiment, A various deformation | transformation is possible.

  For example, in the above-described embodiment, the case where the present invention is applied to the plasma processing of a glass substrate for FPD has been described.

  In addition, the number of dielectric layers in the focus ring is exemplified by two layers as shown in FIGS. 2 to 6 and 8 or three layers as shown in FIG. It is not limited to two or three layers.

  Further, the number of divisions in the focus ring is four divisions as shown in FIG. 3, but the number of divisions of the focus ring is not limited to four divisions.

  Furthermore, the several embodiments described above can be implemented in any combination.

  2 ... processing chamber (processing chamber), 5 ... base material (lower electrode), 5a ... convex part, 5b ... flange part, 6 ... focus ring, 6a ... low dielectric constant dielectric, 6a1-6a4 ... split member, 6b ... Plasma-resistant dielectric, 6b1 to 6b4 ... split member, 7 ... insulating ring, 9 ... joint of split members 6a1 to 6a4, 10 ... joint of split members 6b1 to 6b4, 20 ... shower head (upper electrode), 51 ... dielectric Body sealing member, 52... Dielectric spacer, 61.

Claims (11)

It is disposed as a mounting table for mounting the object to be processed into the processing chamber for performing a plasma treatment, and the convex portion, on the flange portion of the electrode having a flange portion around the protrusion, the protrusion A focus ring that surrounds the periphery of the unit and concentrates the high-frequency electric field above the object to be processed placed on the mounting table ,
It has a multilayer structure in which a plurality of dielectrics having different dielectric constants are laminated,
Among the plurality of dielectrics having different dielectric constants, a low dielectric constant dielectric having a low dielectric constant is disposed on the flange side of the electrode , and the dielectric constant is higher than the dielectric constant of the low dielectric constant dielectric, And a plasma resistant dielectric having a higher plasma resistance than the low dielectric constant dielectric is disposed on the processing space side of the processing chamber,
Each of the low dielectric constant dielectric and the plasma resistant dielectric is a divided type in which a plurality of divided members are connected,
The focus ring , wherein a position of a joint of the dividing member is different between the low dielectric constant dielectric and the plasma resistant dielectric . The horizontal width of the low dielectric constant dielectric is wider or narrower than the horizontal width of the flange portion, and narrower than the horizontal width of the plasma-resistant dielectric. Item 4. The focus ring according to item 1 . Further comprising an insulating ring outside the focus ring;
The focus ring according to claim 1 or 2 , wherein a boundary surface between the focus ring and the insulating ring has a key shape or a step shape. The focus ring according to claim 3 , wherein the insulating ring has a multiple structure. The dielectric seal member is further comprised between the side surface of the said convex part, and the inner surface located in the said convex part side of the said low dielectric constant dielectric material, The Claim 1 thru | or 4 characterized by the above-mentioned. The focus ring according to any one of the above. 6. The focus ring according to claim 5 , wherein a dielectric constant of the dielectric seal member is equal to or lower than a dielectric constant of the plasma-resistant dielectric. Wherein between the dielectric seal member and the flange portion, the focus ring of claim 5 or claim 6, characterized in that the dielectric spacer further comprises. The focus ring according to claim 7 , wherein a dielectric constant of the dielectric spacer is equal to or less than a dielectric constant of the plasma-resistant dielectric. The focus ring according to any one of claims 1 to 8 , wherein high-frequency power is applied to the electrode. The focus ring according to any one of claims 1 to 9 , wherein the low dielectric constant dielectric is a porous dielectric. A processing chamber for performing plasma processing on an object to be processed;
An upper electrode disposed in the processing chamber;
A lower electrode having a convex portion and a flange portion around the convex portion, disposed as a mounting table for placing the object to be processed at a position facing the upper electrode in the processing chamber; equipped with,
The plasma processing apparatus according to claim 1, wherein the focus ring according to claim 1 is attached to the flange portion of the lower electrode so as to surround the convex portion .

Images