JP2006319192A - Electrode and plasma process unit employing it - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electrode which can be supplied with high power and can perform plasma processing stably for a long time, and to provide a plasma processing unit employing that electrode. <P>SOLUTION: The electrode comprises metal electrodes 11 and 12, dielectrics 21 and 22, thin films 31 and 32, and cushion members 41 and 42. The dielectrics 21 and 22 are arranged oppositely to the metal electrodes 11 and 12. The thin films 31 and 32 are formed to cover the surface of the dielectrics 21 and 22 opposing the metal electrodes 11 and 12 at least partially. The cushion members 41 and 42 are conductive members for connecting the metal electrodes 11 and 12 with the thin films 31 and 32. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an electrode and a plasma processing apparatus using the electrode, and more specifically, an electrode capable of supplying a large amount of power and stably performing plasma treatment under a pressure at or near atmospheric pressure for a long time, and the electrode The present invention relates to a plasma processing apparatus using the above.

  Currently, in order to manufacture various electronic devices such as semiconductors, liquid crystal displays, organic electroluminescence displays, solar cells, etc., plasma processing apparatuses that perform etching, film formation, ashing, or surface hydrophilization treatment by plasma treatment are known. . Most of them are performed by generating plasma under a pressure of about 0.1 Pa to 1 kPa. In order to maintain the pressure in the plasma processing apparatus, a vacuum vessel is required. Therefore, (1) the size of the device is larger than the size of the electrode part, (2) the processing speed cannot be increased because the density of the active species of the plasma is small, and (3) vacuum compared to the time of the plasma processing. There is a problem that the time for exhausting and releasing to the atmosphere is longer, that is, the processing time per substrate to be processed becomes longer.

  In order to solve the above problems, a technique for performing plasma treatment under atmospheric pressure or a pressure near atmospheric pressure has been developed. According to this technique, since plasma processing is performed under atmospheric pressure or pressure near atmospheric pressure, (1) the apparatus size can be reduced because a vacuum vessel is not required, and (2) the density of active species of plasma is high. Therefore, there is an advantage that the processing speed can be increased, and (3) the processing time per substrate to be processed can be substantially equal to the plasma processing time.

  However, when the metal part of the electrode to be plasma-treated under this atmospheric pressure or pressure near atmospheric pressure is exposed, arc discharge will occur if the input power for generating plasma is increased in order to increase the processing speed. End up. For this reason, a technique for coating the surface of a metal electrode with a solid dielectric has been developed.

  As a method of coating a metal electrode with a solid dielectric, for example, there is a method of forming a dielectric such as alumina on the metal electrode by thermal spraying. The dielectric formed by this thermal spraying method has a porous structure as compared with a high-density sintered dielectric manufactured by, for example, a HIP (hot isostatic pressing) process using a powder material having a particle diameter of 2 μm. Therefore, the dielectric breakdown voltage is lowered. Also, when high power is applied to the electrode to continuously generate plasma, heat is generated by the power consumed by the plasma generator, and the temperature of the dielectric and the electrode rises. Along with this temperature rise, there arises a difference in the amount of thermal expansion between the electrode and the dielectric, which is represented by the product of the coefficient of thermal expansion, the amount of temperature rise, and the length of the object. For this reason, there is a problem in that stress at the interface between the electrode and the dielectric is increased, and the dielectric is cracked and dielectric breakdown is likely to occur.

  Further, in an electrode in which a dielectric is provided on the plasma discharge surface side of the metal electrode, a gap is partially generated between the metal electrode and the dielectric due to processing accuracy and assembly accuracy. This gap is effective in avoiding the generation of stress due to the difference in thermal expansion. However, when high power is applied to the electrode under atmospheric pressure or pressure near atmospheric pressure, unnecessary discharge occurs due to the gap. Therefore, the power efficiency for plasma generation could not be increased.

  In order to solve the above problem, for example, as described in JP-A-7-220895 (Patent Document 1), an inner wall of a glass tube is subjected to silver plating, and an AC voltage is applied using the plated film as an electrode. An electrode for glow discharge is disclosed.

  Further, for example, an electrode described in JP-A-11-43781 (Patent Document 2) is disclosed.

FIG. 10 is a cross-sectional view of the electrode disclosed in Patent Document 2. The electrode 200 is formed by reliably depositing the metal electrodes 201 and 202 by plating, vapor deposition, thermal spraying, or coating the sintered ceramics 211 and 212, and applying an AC voltage to the electrodes. The problem is solved.
Japanese Patent Laid-Open No. 7-220895 JP 11-43781 A

  However, the electrodes disclosed in Patent Documents 1 and 2 formed by plating, vapor deposition, thermal spraying, coating, or the like can have an electrode thickness of only about several tens of microns. In addition, the conductivity of the film is lower than that of bulk metal, and even when high power is applied to the electrode, the loss at the electrode increases and the influence of heat generation increases. Therefore, in the plasma processing using He (helium) gas having a low ionization voltage as a reaction gas, the thin film electrode as described above can be used. However, if plasma processing is used for etching or film formation using halogen- or silane-based reactive gases with high ionization voltage, the discharge may not be stable unless high power is applied to the electrode, or the process speed may be high. It may be insufficient. In such a case, if a thin film electrode as described above is used as the electrode, the Joule heat increases because the resistance is higher than that of the bulk metal electrode. Therefore, there is a problem that the temperature of the thin film electrode rises and melts, or that the temperature rise causes a difference in thermal expansion from the dielectric, causing the thin film to peel from the dielectric.

  SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide an electrode capable of supplying a large amount of power and capable of performing plasma processing stably for a long time and a plasma process apparatus using the electrode.

  The electrode according to the present invention includes a metal electrode, a dielectric, a thin film, and a buffer member. The dielectric is disposed so as to face the metal electrode. The thin film is formed so as to cover at least a part of the surface of the dielectric facing the metal electrode. The buffer member is a conductive member that connects the metal electrode and the thin film.

  Thereby, the buffer member exists as a medium between the metal electrode and the thin film. The buffer member has good contact between the dielectric and the metal electrode formed depending on the surface shape of the dielectric. Therefore, the heat of the dielectric heated by the plasma can be transmitted to the metal electrode through the buffer member. Therefore, an increase in electrode temperature can be suppressed even when a large amount of power is applied.

  In the above electrode, the buffer member is preferably a spring-like alloy. The “buffer member” in this case means an elastic body that can absorb the respective elongations caused by the thermal expansion of the metal electrode and the dielectric. The “spring-like alloy” means an alloy material having elasticity.

  Thereby, even when heat is applied to the electrode, it is possible to prevent a contact failure portion such as a gap from being generated in the connection portion between the metal electrode and the thin film by the buffer member.

  Preferably, in the above electrode, the buffer member includes any one of a conductive adhesive and a conductive paste.

  Thereby, since the contact area of a buffer member and a thin film or a metal electrode can be enlarged, contact resistance can be reduced.

  In the above electrode, preferably, the electrode that generates plasma, and the metal electrode and the thin film are connected to at least one position on the side opposite to the surface of the dielectric that is in contact with the region that generates plasma.

  As a result, the temperature rise of the electrode can be suppressed even when a large amount of power is applied, and plasma processing can be performed stably for a long time.

  Preferably, in the above electrode, the projected shape of the projected metal electrode is included in the projected shape of the dielectric projected on the virtual plane with respect to the virtual plane perpendicular to the direction in the direction of viewing the dielectric from the metal electrode. The shape of the dielectric has been determined.

  Thereby, discharge can be prevented. In addition, since the electrode can be used to the maximum extent, a large amount of power can be input efficiently.

  The plasma process apparatus of the present invention further includes at least one electrode, and further includes a gas introduction unit that introduces a reactive gas in the vicinity of the electrode, and a voltage application unit that applies a high-frequency voltage to the electrode.

  As a result, the temperature rise of the electrode can be suppressed even when a large amount of power is applied, and plasma processing can be performed stably for a long time.

  In the above plasma processing apparatus, preferably, plasma is generated under atmospheric pressure or a pressure near atmospheric pressure.

  As a result, an increase in electrode temperature can be suppressed even when a large amount of electric power is applied under atmospheric pressure or a pressure near atmospheric pressure, and plasma processing can be performed stably for a long time.

The “pressure in the vicinity of atmospheric pressure” means a pressure range of 1.0 × 10 ⁴ Pa or more and 1.1 × 10 ⁵ Pa or less.

  As described above, according to the present invention, since the buffer member connects the thin film that covers a part of the dielectric and the metal electrode, even if a large amount of electric power is applied under a pressure at or near atmospheric pressure. The temperature rise of the electrode can be suppressed, unnecessary discharge can be eliminated, and plasma processing can be performed stably for a long time.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the following drawings, the same or corresponding parts are denoted by the same reference numerals, and description thereof will not be repeated.

(Embodiment 1)
FIG. 1 is a schematic cross-sectional view showing an electrode according to Embodiment 1 of the present invention. An electrode according to Embodiment 1 of the present invention will be described with reference to FIG. The electrode according to the first embodiment of the present invention is, for example, a direct discharge type electrode as shown in FIG. The direct discharge type electrode includes an electrode 51 on the high frequency application side and an electrode 52 on the ground side. As shown in FIG. 1, the electrode 51 on the high frequency application side according to Embodiment 1 of the present invention includes, for example, a metal electrode 11, a dielectric 21, a thin film 31, and a buffer member 41. Further, as shown in FIG. 1, the ground-side electrode 52 according to the first embodiment of the present invention includes, for example, a metal electrode 12, a dielectric 22, a thin film 32, and a buffer member 42.

  The electrode 51 is connected to the voltage applying means 71 via the matching unit 72, and the electrode 52 is grounded, whereby a high frequency voltage is applied between the electrodes 51 and 52. A substrate 61 to be processed is disposed between the electrode 51 and the electrode 52.

  The dielectrics 21 and 22 are disposed so as to face the metal electrodes 11 and 12, respectively. The thin films 31 and 32 are formed so as to cover at least a part of the surfaces of the dielectrics 21 and 22 facing the metal electrodes 11 and 12, respectively. The thin films 31 and 32 are conductive. The buffer members 41 and 42 connect the metal electrodes 11 and 12 and the thin films 31 and 32, respectively. Moreover, the buffer members 41 and 42 are conductive.

  The thin films 31 and 32 are formed so as to cover a part of the dielectrics 21 and 22, and the thin films 31 and 32 are formed under a certain condition. For example, even if heat is applied between the thin films 31 and 32 and the dielectrics 21 and 22, the thin films 31 and 32 need not be peeled off. When the thin films 31 and 32 are formed on the dielectrics 21 and 22, the films are formed with good adhesion, with the material, the temperature at the time of film formation, and the like being fixed conditions. Alternatively, in order to prevent stress from being applied to the thin films 31 and 32, the film forming method, the film forming speed at the time of film forming, and the like are set to a certain condition, an additive is added, or an alloy is formed.

  The electrodes 51 and 52 are electrodes that generate plasma. There are two positions where the metal electrodes 11 and 12 and the thin films 31 and 32 are connected to each other on the side opposite to the surfaces of the dielectrics 21 and 22 in contact with the region where the plasma A is generated.

  In a direction D in which the dielectric 22 is viewed from the metal electrode 11 of the electrode 51 on the high frequency application side, a projected shape L11 of the projected metal electrode 11 with respect to a virtual plane H perpendicular to the direction D is a dielectric projected onto the virtual plane H. The shape of the dielectric 21 is determined so as to be included in the projected shape L21 of 21. The same applies to the relationship between the metal electrode 12 and the dielectric 22 in the ground-side electrode 52.

For example, Al (aluminum) is used as the material of the metal electrodes 11 and 12. The metal electrodes 11 and 12 are preferably made of a metal material such as Al or Cu (copper) or an alloy such as an alloy having a conductivity of 1 × 10 ⁶ [1 / Ω · m] or more. Furthermore, it is preferable to use a perfect conductor having an electrical conductivity of ∞. This is because high-frequency propagation loss increases when a material having a conductivity smaller than 1 × 10 ⁶ [1 / Ω · m] is used. In the case of increasing the size of the electrode or increasing the frequency of the power source, it is preferable to use a material having a conductivity of 1 × 10 ⁷ [1 / Ω · m] or higher, such as Al or Cu.

  As the material of the dielectrics 21 and 22, for example, sintered alumina is used. As the materials for the dielectrics 21 and 22, it is preferable to use a material excellent in electrical insulation, heat resistance, corrosion resistance, plasma resistance, workability, and low loss. As materials having such properties, the dielectrics 21 and 22 may be made of, for example, zirconia-based, silicon nitride-based, or aluminum nitride-based sintered ceramics. In addition, as other materials of the dielectrics 21 and 22, a material having high conductivity among Ag (silver), Al, and an alloy material containing the material can be used. In addition, the shape of the dielectrics 21 and 22 is a flat plate shape.

  The thin films 31 and 32 are formed in a thickness of 1 μm or more and 100 μm or less on the surfaces of the dielectrics 21 and 22 on the metal electrodes 11 and 12 side by vapor deposition, plating, thermal spraying, or the like.

The buffer members 41 and 42 are made of BeCu having a spring property and good conductivity. When BeCu having a spring property is used, the conductivity can be made higher than that of a conductive adhesive or a conductive paste. Moreover, the width is 5 mm to 20 mm and the thickness is 10 μm to 1 mm. The buffer members 41 and 42 are connected at intervals of 1 mm or more and 10 mm or less over the outer periphery of each surface where the metal electrodes 11 and 12 and the thin films 31 and 32 face each other. As a material of the buffer members 41 and 42, it is preferable to use a material having a spring property and a conductivity of 1 × 10 ⁶ [1 / Ω · m] or more. For example, in addition to the above materials, SUS, brass, or the like can be used. In addition to the material having the spring property as described above, for example, a material including any one of a conductive adhesive including an Ag filler and a conductive paste can be used. When a material containing either one of a conductive adhesive and a conductive paste is used as a material, the contact area with the thin films 31 and 32 and the metal electrodes 11 and 12 can be increased as compared with a spring material. Contact resistance can be lowered.

  Next, the electromagnetic field in the electrode 51 will be described. In the electrode 51, as shown in FIG. 1, when the distance D41 between the metal electrode 11 and the thin film 31 is 0.1 mm, an electromagnetic field analysis is performed to know the electric field at the distance D41 of the gap. It was. The results are shown in FIG. FIG. 2 is a diagram showing the electric field strength between the thin film 31 and the metal electrode 11. In FIG. 2, the vertical axis represents the electric field strength (unit: au), and the horizontal axis represents the position (unit: mm) from the end of the thin film 31. As shown in FIG. 2, the buffer members 41 are arranged at three positions at intervals of 4 mm, and the electric field strength at the gap is 2 compared to the electric field strength of the electrode not having the buffer member 41. It has become more than an order of magnitude lower. Since the gap portion is surrounded by a metal material, the electric field in the gap portion is zero, so unnecessary discharge cannot occur.

  In addition, a reactive gas is introduced between the electrode 51 and the electrode 52 under atmospheric pressure or a pressure near atmospheric pressure, and plasma A is generated by applying, for example, a high frequency voltage having a frequency of 13.56 MHz by the voltage applying means 71. Then, unnecessary discharge does not occur in the gap. In addition, since the electrode is not only a thin film electrode but mainly a metal electrode, the heat capacity is large and the temperature rise of the electrodes 51 and 52 can be suppressed. Therefore, the plasma A can be generated efficiently, and the plasma A can be supplied to the substrate 61 to be processed.

  On the other hand, when the buffer member 41 is not provided, even if the thin film 31 is formed, the electric field strength in the gap between the metal electrode 11 and the thin film 31 (in the case of non-connection in FIG. 2) is the electric field strength when discharging. It became almost equivalent. Further, when high power is applied, unnecessary discharge occurs in the gap, and power for supplying the plasma A to the substrate 61 cannot be efficiently supplied.

  Next, a plasma processing apparatus using the electrodes 51 and 52 according to the first embodiment of the present invention will be described. FIG. 3 is a sectional view showing the plasma processing apparatus according to the first embodiment of the present invention. With reference to FIG. 1 and FIG. 3, the plasma process apparatus by Embodiment 1 of this invention is demonstrated. The plasma processing apparatus according to the first embodiment of the present invention is a plasma processing apparatus using, for example, direct discharge electrodes 51 and 52 as shown in FIGS.

  The plasma processing apparatus 10 includes electrodes 51 and 52, a gas introduction unit 81, a gas discharge unit 91, a voltage application unit 71, a matching unit 72, a transfer unit 101, and a shield unit 111. The gas introduction means 81 introduces a reactive gas in the vicinity of the electrodes 51 and 52. The voltage applying unit 71 applies a high frequency voltage to the electrodes 51 and 52.

  As the substrate 61, for example, a glass substrate on which a Si-based thin film and a resist pattern are formed is used. The substrate 61 to be processed is transferred to the plasma processing apparatus 10 by the transfer unit 101 with the long axis direction of the substrate 61 to be processed (from left to right in FIG. 3) as the transfer direction. As a conveyance method of the conveyance unit 101, for example, a roller conveyance method is used, but is not particularly limited to this configuration. For example, a roller conveyance method or a belt conveyance method may be used.

  For example, a gas obtained by mixing helium gas, fluorine-based gas, and oxygen gas is introduced into the gas introduction means 81 as a reaction gas. The reaction gas is not particularly limited to this, and the type, mixing ratio, and flow rate of the reaction gas can be appropriately selected depending on the film type of the film to be processed, the selection ratio between the lower layer film and the resist, the processing time, and the like.

  The reaction gas is introduced from the gas introduction means 81, passes between the electrodes 51 and 52, passes through a path along which the substrate 61 is transported, and is discharged from the gas discharge unit 91. The electrodes 51 and 52 are disposed in a shield part 111 made of aluminum or the like. The shield part 111 is configured such that electromagnetic waves do not leak to the outside even when a high frequency voltage is applied to the electrodes 51 and 52 disposed therein.

  In the first embodiment, as shown in FIG. 3, the thicknesses D21 and D22 of the dielectrics 21 and 22 are 5 mm, respectively, and the distance D10 between the surfaces of the dielectrics 21 and 22 on the other electrode side (between opposing surfaces). Is 5 mm.

  Next, an operation method of the plasma process apparatus 10 will be described. In the plasma process apparatus according to the first embodiment, for example, a case where an etching process is performed as a plasma process will be described.

  For example, voltage applying means 71 having a frequency of 13.56 MHz is connected to the electrode 51 through a matching unit 72. Next, a high frequency voltage is applied under atmospheric pressure or a pressure near atmospheric pressure to generate plasma A between the electrode 51 and the electrode 52. Then, an etching process was performed as a plasma process on the Si-based thin film on one or both surfaces of the substrate 61 to be processed, which is disposed and transported between the electrodes 51 and 52.

  The frequency of the voltage applying means 71 is related to the process processing speed and the uniformity of the process and has a trade-off relationship, and can be appropriately selected from a frequency of about 10 kHz to 100 MHz depending on the purpose. In addition, since the power is related to the process processing speed, it is possible to appropriately select a power that provides a desired processing speed.

  As described above, the electrodes 51 and 52 according to the first embodiment include the conductive buffer members 41 and 42 that connect the metal electrodes 11 and 12 and the thin films 31 and 32. Therefore, even if the thin films 31 and 32 and the metal electrodes 11 and 12 are thermally expanded due to heating and a difference in displacement due to the expansion is generated, the buffer members 41 and 42 absorb the metal electrodes 11 and 12 and the thin films 31 and 32. Thus, no contact failure portion such as a gap occurs at the connection portion. On the other hand, even if the thermal expansion does not occur, since the thin films 31 and 32 are formed on the dielectrics 21 and 22, the shape of the thin films 31 and 32 is formed depending on the surface shape of the dielectrics 21 and 22. . Therefore, since the thin films 31 and 32 and the metal electrodes 11 and 12 are brought into contact with the buffer members 41 and 42 as mediators, the difficulty of contact is avoided. Therefore, the electrodes 51 and 52 do not generate cracks or the like in the dielectrics 21 and 22 through the buffer members 41 and 42 even when a large electric power is applied under atmospheric pressure or a pressure near atmospheric pressure. , 22 can be transmitted to the metal electrodes 11 and 12, so that the temperature rise of the electrodes 51 and 52 can be suppressed, and unnecessary plasma discharge can be eliminated and plasma treatment can be stably performed for a long time.

  The buffer members 41 and 42 are made of a spring-like alloy (alloy having spring properties). Therefore, the conductivity can be increased. Therefore, it can serve as a buffer member.

  Furthermore, the electrodes 51 and 52 are electrodes that generate plasma, and the positions where the metal electrodes 11 and 12 and the thin films 31 and 32 are connected are the surfaces of the dielectrics 21 and 22 that are in contact with the region where the plasma A is generated. There is at least one location on the opposite side. Therefore, even if large power is applied, the heat applied to the dielectrics 21 and 22 can be transmitted to the metal electrodes 11 and 12 through the buffer members 41 and 42, so that the temperature rise of the electrodes can be suppressed. Plasma treatment can be performed stably for a long time without unnecessary discharge.

  Furthermore, in the direction D when the dielectric 21 is viewed from the metal electrode 11, the projected shape L11 of the projected metal electrodes 11 and 12 with respect to the virtual surface H perpendicular to the direction D is that of the dielectric 21 projected onto the virtual surface H. The shape of the dielectric is determined so as to be included in the projected shape L21. Therefore, discharge can be prevented.

  The plasma processing apparatus 10 according to Embodiment 1 includes the electrodes 51 and 52 described above, a gas introduction unit 81 that introduces a reactive gas in the vicinity of the electrodes 51 and 52, and a voltage application unit that applies a high-frequency voltage to the electrode 51. 71. Therefore, even when a large amount of electric power is applied at atmospheric pressure or a pressure near atmospheric pressure, the electric power can be used efficiently and plasma treatment can be performed stably for a long time.

(Embodiment 2)
FIG. 4 is a schematic cross-sectional view showing an electrode according to Embodiment 2 of the present invention. With reference to FIG. 4, the electrode by Embodiment 2 of this invention is demonstrated. The electrode according to the second embodiment of the present invention is, for example, a remote type electrode as shown in FIG. Referring to FIG. 4, the configuration of the electrode according to the second embodiment is basically the same as that of electrodes 51 and 52 according to the first embodiment of the present invention, but one electrode 51 on the high frequency application side. 1 and the ground electrode 52 is different from the electrode shown in FIG.

  Specifically, the electrodes 51 and 52 have the same configuration as in the first embodiment. As shown in FIG. 4, the electrodes 51 and 52 are configured such that the high-frequency application-side electrode 51 is sandwiched between two ground-side electrodes 52, and are arranged side by side in FIG.

  As shown in FIG. 4, the dielectric 21 in the electrode 51 on the high frequency application side has a substantially U-shaped cross section. The dielectric 22 in the ground-side electrode 52 has a substantially L-shaped cross section.

  The buffer member 41 connects the metal electrode 11 and the thin film 31. The buffer member 41 is arranged with a width of 10 mm and an interval of 5 mm on the outer periphery of the facing surface between the metal electrode 11 and the thin film 31 (the end of the metal electrode 11 on the upper opening side of the dielectric 21). .

  Next, the function of the buffer member 41 will be described. When the cross section of the dielectric 21 is processed into a substantially U shape as described above, a gap may be generated between the metal electrode 11 and the thin film 31 depending on the processing accuracy and assembly accuracy of the corners. Similarly, when the cross section of the dielectric 22 on the electrode 52 side is processed into a substantially L shape as described above, a gap may be formed between the metal electrode 12 and the thin film 32. However, even if such a gap occurs, by disposing the buffer members 41 and 42 so as to connect the metal electrodes 11 and 12 and the thin films 31 and 32 as described above, unnecessary discharge in the gap is prevented. It does not occur.

  Further, since the electrodes 51 and 52 are metal electrodes, the heat capacity is large, and the temperature rise of the electrodes 51 and 52 is suppressed. Therefore, the plasma B can be generated efficiently, and the plasma B can be supplied to the substrate 61 to be processed.

  On the other hand, when the buffer members 41 and 42 are not provided, even if the thin films 31 and 32 are formed so as to cover a part of the dielectrics 21 and 22, respectively, Unnecessary discharge occurred in the gaps between them. As a result, power could not be efficiently supplied to the plasma processing unit.

  The shapes of the dielectrics 21 and 22 shown in the second embodiment are not particularly limited to this. For example, any shape may be used as long as it surrounds the metal electrodes 11 and 12.

  Next, a plasma processing apparatus using the electrodes 51 and 52 according to the second embodiment of the present invention will be described. FIG. 5 is a cross-sectional view showing a plasma processing apparatus according to Embodiment 2 of the present invention. With reference to FIG. 4 and FIG. 5, the plasma process apparatus by Embodiment 2 of this invention is demonstrated. The plasma processing apparatus according to the second embodiment of the present invention is a plasma processing apparatus using, for example, remote-type electrodes 51 and 52 as shown in FIGS.

  Referring to FIG. 5, the configuration of plasma processing apparatus 20 according to the second embodiment is basically the same as that of plasma processing apparatus 10 according to the first embodiment of the present invention. 52 is different from the plasma processing apparatus 10 shown in FIG.

  Specifically, the plasma process apparatus 20 includes one high-frequency application electrode 51, two ground electrodes 52, a gas introduction unit 81, two gas discharge units 91, and a voltage application unit 71. A matching unit 72, a transport unit 101, and a shield unit 111.

  The reaction gas is introduced from the gas introduction means 81, is branched into two flow paths between the electrodes 51 and 52, passes through a path along which the substrate to be processed 61 is transported, and from two gas discharge portions 91. Discharged.

  In the second embodiment, as shown in FIG. 5, the thicknesses D21 and D22 of the dielectrics 21 and 22 are 5 mm, respectively, and the distance D20 between the surfaces of the dielectrics 21 and 22 on the other electrode side is 1 mm.

  Next, an operation method of the plasma process apparatus 20 will be described. In the plasma process apparatus according to the second embodiment, for example, a case where an etching process is performed as a plasma process will be described.

  For example, voltage applying means 71 having a frequency of 13.56 MHz is connected to the electrode 51 through a matching unit 72. Next, a high frequency voltage is applied under atmospheric pressure or a pressure near atmospheric pressure to generate plasma B between the electrode 51 and the electrode 52. Then, ions and active species are carried to the substrate 61 by the gas flow. Thereby, the etching process was performed on the Si-based thin film of the substrate 61 as a plasma process remotely.

  In the second embodiment, one electrode 51 and two electrodes 52 are provided. However, the present invention is not particularly limited to this configuration. For example, a configuration in which the number of discharge points is increased with two electrodes 51 and three electrodes 52, or a configuration in which a plurality of sets of electrodes according to the second embodiment are provided, for example, may be configured to increase the plasma processing speed.

  As described above, the electrodes 51 and 52 according to the second embodiment include the conductive buffer members 41 and 42 that connect the metal electrodes 11 and 12 and the thin films 31 and 32. Therefore, even if the electrodes 51 and 52 apply a large amount of power under atmospheric pressure or a pressure close to atmospheric pressure, the heat applied to the dielectrics 21 and 22 through the buffer members 41 and 42 is used as the metal electrode 11, 22. 12, the temperature rise of the electrode can be suppressed, and unnecessary plasma discharge can be eliminated and stable plasma treatment can be performed for a long time.

  The plasma processing apparatus 20 according to the second embodiment includes the electrodes 51 and 52 described above, a gas introduction unit 81 that introduces a reactive gas in the vicinity of the electrodes 51 and 52, and a voltage application unit that applies a high-frequency voltage to the electrode 51. 71. Therefore, as a plasma process apparatus using a remote type electrode, even when a large amount of power is applied, the power can be used efficiently, and plasma processing can be performed stably for a long time.

(Embodiment 3)
FIG. 6 is a schematic cross-sectional view showing an electrode according to Embodiment 3 of the present invention. An electrode according to Embodiment 3 of the present invention will be described with reference to FIG. As shown in FIG. 6, the electrode according to the third embodiment of the present invention is an electrode of a system different from, for example, a direct discharge system and a remote system. Referring to FIG. 6, the configuration of the electrode according to the third embodiment is basically the same as that of electrodes 51 and 52 according to the second embodiment of the present invention. Differs from the electrode shown in FIG. 4 in that there is no discharge space.

  Specifically, as shown in FIG. 6, the dielectric 23 is configured to cover both the electrode 51 and the electrode 52. In the dielectric 23, the cross-sectional shape on the high-frequency side electrode 51 side is substantially U-shaped. In the dielectric 23, the cross-sectional shape of the ground side electrode 52 is substantially L-shaped. The electrode 51 and the electrode 52 are configured to discharge in a region on the substrate 61 side.

  Since the discharge space does not exist on the opposing surface side of the electrode 51 and the electrode 52, the dielectric 23 is formed of one member, but is not particularly limited to this configuration. For example, the dielectric 23 may be formed so as to have the above shape with a plurality of components.

  Next, the function of the buffer members 41 and 42 will be described. As described in the second embodiment, since the cross-sectional shape of the dielectric 23 is as described above, a gap may be generated between the metal electrode 11 and the thin films 31 and 32, respectively. However, even if such a gap occurs, unnecessary discharge in the gap does not occur by arranging the buffer members 41 and 42 as described above.

  Moreover, since the electrodes 51 and 52 are metal electrodes, the temperature rise of the electrodes 51 and 52 can be suppressed. Therefore, the plasma C can be generated efficiently, and the plasma C can be supplied to the substrate 61 to be processed.

  On the other hand, when the buffer members 41 and 42 are not provided, unnecessary discharge similarly occurs in the gap portions between the metal electrodes 11 and 12 and the thin films 31 and 32.

  The shape of the dielectric 23 shown in the third embodiment is not particularly limited to this. As long as the side on which the high electric field is generated is surrounded by the dielectric, the cross-sectional shape of the dielectric 23 on the side of the electrode 52 on the ground side may be substantially U-shaped.

  Next, a plasma processing apparatus using the electrodes 51 and 52 according to the third embodiment of the present invention will be described. FIG. 7 is a sectional view showing a plasma processing apparatus according to the third embodiment of the present invention. A plasma processing apparatus according to Embodiment 3 of the present invention will be described with reference to FIGS. As shown in FIGS. 6 and 7, the plasma process apparatus according to the third embodiment of the present invention is a plasma process apparatus using electrodes 51 and 52 of a system different from the direct discharge system and the remote system, for example.

  Referring to FIG. 7, the configuration of plasma processing apparatus 30 according to the third embodiment is basically the same as that of plasma processing apparatus 20 according to the second embodiment of the present invention. 5 is different from the plasma processing apparatus 20 shown in FIG.

  Specifically, the plasma processing apparatus 30 includes one high-frequency application side electrode 51, two ground-side electrodes 52, a gas introduction unit 81, one gas discharge unit 91, and a voltage application unit 71. A matching unit 72, a transport unit 101, and a shield unit 111.

  The reaction gas is introduced from the gas introduction means 81, passes through a path through which the substrate 61 to be processed is conveyed, and is discharged from the gas discharge unit 91. In the plasma process apparatus 30 according to the third embodiment, the reaction gas flow path is one flow path.

  In the third embodiment, as shown in FIG. 7, the thickness D23 of the dielectric 23 is 5 mm.

  Next, an operation method of the plasma process apparatus 30 will be described. In the plasma process apparatus according to the third embodiment, for example, a case where an etching process is performed as a plasma process will be described.

  For example, voltage applying means 71 having a frequency of 13.56 MHz is connected to the electrode 51 through a matching unit 72. Next, a high frequency voltage is applied under atmospheric pressure or a pressure near atmospheric pressure to generate plasma C in the lower region between the electrode 51 and the electrode 52. There are two such regions in the plasma processing apparatus 30. Then, ions and active species act on the substrate 61 to be processed. Thus, an etching process was performed as a plasma process on the Si-based thin film of the substrate 61 to be processed.

  In the third embodiment, one electrode 51 and two electrodes 52 are provided. However, the present invention is not particularly limited to this configuration. For example, a configuration in which the number of discharge locations is increased with two electrodes 51 and three electrodes 52, or a configuration in which a plurality of sets of electrodes according to Embodiment 3 are provided, for example, may be configured to increase the plasma processing speed.

  As described above, the electrodes 51 and 52 according to the third embodiment include the conductive buffer members 41 and 42 that connect the metal electrodes 11 and 12 and the thin films 31 and 32. Therefore, as in the first and second embodiments of the present invention, the electrodes 51 and 52 can suppress the temperature rise of the electrodes even when a large electric power is applied under atmospheric pressure or a pressure near atmospheric pressure, and are unnecessary. Plasma treatment can be performed stably for a long time without discharge.

  The plasma processing apparatus 30 according to the third embodiment includes the electrodes 51 and 52 described above, a gas introduction unit 81 that introduces a reactive gas in the vicinity of the electrodes 51 and 52, and a voltage application unit that applies a high-frequency voltage to the electrode 51. 71. Therefore, as a plasma process apparatus using electrodes other than the direct discharge method and the remote method, even when a large amount of power is applied, the power can be used efficiently and plasma processing can be performed stably for a long time.

  Next, a modification of the third embodiment will be described. FIGS. 8B and 8C are cross-sectional views showing electrodes in Modifications 1 and 2 of the electrode 51 according to Embodiment 3 of the present invention. FIG. 8A is an enlarged cross-sectional view of the electrode 51 shown in FIG.

  FIG. 8B is an enlarged cross-sectional view of the electrode 110 according to the first modification. Referring to FIG. 8B, the configuration of electrode 110 according to Modification 1 has the same configuration as that of electrode 51 according to Embodiment 3, but in the arrangement of metal electrode 11 and thin film 31, FIG. Different from the electrode 51 shown in FIG.

  Specifically, as shown in FIG. 8B, the shape of the dielectric 21 is substantially U-shaped, and the thin film 31 is formed so as to cover the surface facing the metal electrode 11. Therefore, the shape of the thin film 31 is also substantially U-shaped. The metal electrode 11 and the thin film 31 are disposed so as to contact the metal electrode 11 on the lower surface of the thin film 31.

  In the electrode 51 according to the third embodiment and the electrode 150 according to the reference example shown in FIG. 9 described later, no discharge occurs in the gap, but the temperature of the dielectric 21 rises, the dielectric 21 breaks, and high power is input. There are cases where it is not possible. The cause of the crack of the dielectric 21 is considered as follows.

When the plasma is generated, the surface of the dielectric 21 on the plasma generation side is heated by the plasma C. The electrode 51 and the electrode 150 have a gap between the thin film 31 and the metal electrode 11 in the vicinity of the generated plasma. This gap is an air layer. The thermal conductivity of air is as low as 2.6 × 10 ⁻² [W / m · K]. Therefore, for example, a flow path is provided in the metal electrode 11 (not shown), and a coolant such as water around 20 ° C. is circulated to cool the metal electrode 11. However, the surface of the dielectric 21 is difficult to cool because of the air layer. Therefore, the surface of the dielectric 21 may be 500 ° C. or more, and stress is locally generated due to the difference in thermal expansion between the dielectric 21 and the metal electrode 11, the temperature distribution, etc., and the dielectric 21 is cracked. It is thought that it may occur.

  However, in the electrode 110 according to the first modification, the plasma treatment can be performed by arranging the thin film 31 and the metal electrode 11 in contact with each other. Therefore, the electrode 110 can improve heat conduction and electric conduction in a region where the heat flux is large, such as a region where the plasma C is generated. Specifically, the metal electrode 11 and the dielectric 21 are in contact with each other at the lower part of the dielectric 21 that is a region near the region where plasma is generated. Therefore, the heat applied to the dielectric 21 by plasma through the contact portion can be transmitted to the metal electrode 11. As a result, the dielectric 21 can be sufficiently cooled. Therefore, since the temperature of the surface of the dielectric 21 can be lowered to 300 ° C. or less, the dielectric 21 is not cracked, and unnecessary discharge in the gap can be prevented.

  FIG. 8C is an enlarged cross-sectional view of the electrode 120 according to the second modification. Referring to FIG. 8C, the configuration of the electrode 120 according to the second modification includes the same configuration as that of the electrode 51 according to the third embodiment, but the arrangement of the buffer member 41 is illustrated in FIG. Different from the electrode 51.

  Specifically, as shown in FIG. 8C, there are three positions where the metal electrode 11 and the thin film 31 are connected on the side opposite to the surface of the dielectric 21 in contact with the region where the plasma C is generated. The three positions to be connected are one inner peripheral lower surface and two inner peripheral upper surfaces in the U-shaped metal electrode 11.

  If the electrode 120 according to the modified example 2 has the above-described configuration, and the buffer member 41 has a high conductivity and a thermal conductivity of 10 [W / m · K] or higher, the metal electrode 11 and the thin film The heat conduction with 31 can be increased. Therefore, the cooling effect by a coolant such as water provided on the metal electrode 11 is increased, and the surface temperature of the dielectric 21 can be lowered to 300 ° C. or lower. Therefore, it is possible to prevent the dielectric 21 from cracking even when high power is applied.

  FIG. 9 is an enlarged cross-sectional view of an electrode 150 according to a reference example. Referring to FIG. 9, the configuration of electrode 150 according to the reference example is basically the same as that of electrode 51 according to the third embodiment, except that buffer member 41 is not provided, metal electrode 11, and dielectric. The shape of the body 21 is different from the electrode 51 shown in FIG.

  Specifically, the cross-sectional shape of the metal electrode 11 is substantially T-shaped, and the cross-sectional shape of the dielectric 21 is substantially U-shaped. And the metal electrode 11 is provided so that the thin film 31 formed in the upper surface of the dielectric material 21 may be contact | abutted.

  By making the electrode 150 according to the reference example into the above-described shape, the metal electrode 11 and the thin film 31 can be electrically connected under the flange portion protruding outside the metal electrode 11, and a large amount of power is input to the electrode 150. Even in such a case, it is possible to adopt a configuration in which no discharge occurs between the metal electrode 11 and the thin film 31.

  The embodiment disclosed this time should be considered as illustrative in all points and not restrictive. The scope of the present invention is shown not by the above-described embodiment but by the scope of claims, and is intended to include all modifications within the meaning and scope equivalent to the scope of claims.

It is a cross-sectional schematic diagram which shows the electrode by Embodiment 1 of this invention. It is a figure which shows the electric field strength between a thin film and a metal electrode. It is sectional drawing which shows the plasma process apparatus by Embodiment 1 of this invention. It is a cross-sectional schematic diagram which shows the electrode by Embodiment 2 of this invention. It is sectional drawing which shows the plasma process apparatus by Embodiment 2 of this invention. It is a cross-sectional schematic diagram which shows the electrode by Embodiment 3 of this invention. It is sectional drawing which shows the plasma process apparatus by Embodiment 3 of this invention. (A) is an expanded sectional view which shows the electrode by Embodiment 3 of this invention, (B) is an expanded sectional view which shows the electrode by the modification of the electrode by Embodiment 3 of this invention, ( C) is an enlarged cross-sectional view showing an electrode according to another modification. It is an expanded sectional view which shows the electrode by a reference example. It is sectional drawing which shows the electrode disclosed by patent document 2. FIG.

Explanation of symbols

  10, 20, 30 Plasma process apparatus, 11, 12 Metal electrode, 21-23 Dielectric, 31, 32 Thin film, 41, 42 Buffer member, 51, 52, 110, 120, 150 Electrode, 61 Substrate, 71 Voltage Application means, 72 Matching device, 81 Gas introduction means, 91 Gas discharge section, 101 Conveyance section, 111 Shield section, 200 electrodes, 201 Metal electrodes, 211, 212 Sintered ceramics, AC plasma, D direction, H virtual surface.

Claims (7)

A metal electrode;
A dielectric disposed to face the metal electrode;
A conductive thin film formed to cover at least a part of a surface of the dielectric material facing the metal electrode;
An electrode comprising: a conductive buffer member that connects the metal electrode and the thin film.   The electrode according to claim 1, wherein the buffer member is a spring-like alloy.   The electrode according to claim 1, wherein the buffer member includes any one of a conductive adhesive and a conductive paste. An electrode for generating plasma,
The position where the metal electrode and the thin film are connected to each other is at least one on the side opposite to the surface of the dielectric that is in contact with the region where plasma is generated. The electrode according to item. In the direction of viewing the dielectric from the metal electrode,
The shape of the dielectric is determined so that the projected shape of the metal electrode projected onto the virtual surface perpendicular to the direction is included in the projected shape of the dielectric projected onto the virtual surface. The electrode according to claim 1, characterized in that it is characterized by the following. Comprising at least one electrode according to any one of claims 1 to 5,
Gas introduction means for introducing a reactive gas in the vicinity of the electrode;
A plasma processing apparatus, further comprising voltage applying means for applying a high frequency voltage to the electrode.   The plasma processing apparatus according to claim 6, wherein plasma is generated under atmospheric pressure or a pressure near atmospheric pressure.

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