JP2011100889A - Electrostatic chuck, method of manufacturing electrostatic chuck, and method of regenerating electrostatic chuck - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electrostatic chuck which can be manufactured easily while assuring high electric insulation. <P>SOLUTION: The electrostatic chuck includes an upper plate 12 having substrate holding electrodes 9a and 9b for holding a substrate S, a lower plate 14 having a plasma electrode for generating plasma, and a thermal fusion sheet 13 composed of a fluorine-containing ethylene polymer having a hydroxyl group and interposed between the upper plate 12 and the lower plate 14 in order to bond them each other while insulating electrically from each other. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

The present invention relates to an electrostatic chuck used in a plasma processing apparatus, and more particularly to an electrostatic chuck comprising a laminate of a dielectric upper plate and a conductive lower plate.
The present invention also relates to a method for manufacturing and regenerating such an electrostatic chuck.

  2. Description of the Related Art In a plasma processing apparatus that performs plasma processing on a substrate, an electrostatic chuck is used to hold the substrate without damage under a space where plasma is generated. The electrostatic chuck is composed of a laminate in which an upper plate having dielectric properties and a lower plate having conductivity are joined.

  A substrate holding electrode is installed inside the upper plate, and a high voltage is applied to the electrode from a DC power supply for holding the substrate, and an electrostatic force is placed between the upper plate and the substrate placed on the upper surface of the upper plate. By generating the above, the substrate is held by the electrostatic chuck. On the other hand, the lower plate functions as a plasma electrode for generating plasma. Between the upper plate and the lower plate, an insulating layer that electrically insulates both is interposed. For such an insulating layer, it is required to use a material that does not cause dielectric breakdown even when a high voltage is applied (a material having dielectric breakdown resistance).

  Thus, for example, Patent Document 1 proposes an electrostatic chuck having an insulating layer formed using a brittle material having high insulating properties. In this electrostatic chuck, the occurrence of dielectric breakdown is suppressed by forming a brittle material by an aerosol deposition method and forming an insulating layer with reduced generation of minute cavities.

JP 2008-227190 A

  However, the formation and processing of the brittle material by the aerosol deposition method may cause a great deal of labor and time.

The present invention has been made to solve such a conventional problem, and an object of the present invention is to provide an electrostatic chuck which can be easily manufactured while ensuring high dielectric breakdown resistance.
Another object of the present invention is to provide a method for producing and regenerating such an electrostatic chuck.

In order to achieve the above object, an electrostatic chuck according to the present invention is an electrostatic chuck that holds a substrate exposed to plasma by electrostatic force, and includes an upper electrode having a substrate holding electrode for holding the substrate. The upper plate is composed of a plate, a lower plate having a plasma electrode for generating plasma, and a fluorine-containing ethylenic polymer having a hydroxyl group, and is interposed between the upper plate and the lower plate And a heat-sealing sheet that joins the plate and the lower plate in a state of being electrically insulated from each other.
Here, the lower plate may include a temperature adjusting unit for adjusting the temperature of the substrate.

  An electrostatic chuck manufacturing method according to the present invention is an electrostatic chuck manufacturing method for holding a substrate exposed to plasma by an electrostatic force, and includes an upper plate having a substrate holding electrode for holding the substrate. And a lower plate having a plasma electrode for generating the plasma, with a heat fusion sheet composed of a fluorine-containing ethylenic polymer having a hydroxyl group interposed therebetween, and the heat fusion The upper plate and the lower plate are joined in a state where they are electrically insulated from each other by thermal fusion of sheets.

Furthermore, the electrostatic chuck regeneration method according to the present invention is a method for regenerating an electrostatic chuck in which a substrate exposed to plasma is retained by electrostatic force, and the electrostatic chuck retains the substrate for retaining the substrate. An upper plate having a working electrode, a lower plate having a plasma electrode for generating plasma, and a fluorine-containing ethylenic polymer having a hydroxyl group, and between the upper plate and the lower plate A heat-sealing sheet for interposing and joining the upper plate and the lower plate in an electrically insulated state, and heating the used electrostatic chuck to melt the heat-fusion sheet or Soften, separate the upper plate and the lower plate from each other, replace one of the upper plate and the lower plate with a new one and reuse the other, The part plate and the other reused upper plate or lower plate are laminated with a new heat-sealing sheet composed of a fluorine-containing ethylenic polymer having a hydroxyl group interposed therebetween, and the new plate The new upper plate or lower plate and the other upper plate or lower plate to be reused are joined in a state where they are electrically insulated from each other by heat-sealing of a heat-sealing sheet. .
Here, after the used electrostatic chuck is heated and separated into the upper plate and the lower plate, the other upper plate or the lower plate to be reused is reused by cleaning, and is renewed. The one upper plate or the lower plate may be joined.

  According to the present invention, it is possible to realize an electrostatic chuck that is easy to manufacture while ensuring high dielectric breakdown resistance by using a heat-sealing sheet.

It is sectional drawing which shows the structure of the plasma processing apparatus provided with the electrostatic chuck which concerns on one Embodiment of this invention. It is sectional drawing which shows the structure of an electrostatic chuck. It is sectional drawing which shows the structure of the electrostatic chuck used in other embodiment.

  Hereinafter, the present invention will be described in detail based on preferred embodiments shown in the accompanying drawings.

  FIG. 1 shows a configuration of a plasma processing apparatus including an electrostatic chuck 1 according to an embodiment of the present invention. The plasma processing apparatus has a vacuum chamber 2 that keeps the inside airtight from the outside.

  A gas supply port 3 for supplying a reaction gas is installed on the upper surface in the vacuum chamber 2, and a gas exhaust port 4 for exhausting the reaction gas is installed on the lower surface in the vacuum chamber 2. The gas supply port 3 is connected to a gas supply source (not shown), and a reaction gas for generating plasma by the gas supply source is supplied into the vacuum chamber 2 through the gas supply port 3. Further, the gas exhaust port 4 is connected to a decompression device (not shown), and the vacuum chamber 2 has a predetermined degree of vacuum by the decompression device, and the vacuum chamber 2 has a predetermined degree of vacuum even when the reaction gas is supplied. Make adjustments to maintain. As the decompression device, a vacuum pump, a cryocoil, or the like can be used.

The gas supply port 3 is connected to a shower head holding member 5 formed of a conductive material. The shower head holding member 5 has a gas supply chamber 6 that is a hollow space inside, and a reaction gas is supplied to the gas supply chamber 6 from the gas supply port 3. The shower head holding member 5 and the vacuum chamber 2 are electrically insulated from each other.
A shower head 7 is attached to the lower side of the shower head holding member 5 so as to cover the lower surface of the gas supply chamber 6. The shower head 7 is formed with a plurality of ejection holes 8 penetrating from the upper surface to the lower surface, and the reaction gas supplied from the gas supply chamber 6 is ejected below the shower head 7 through the plurality of ejection holes 8. Is done. The shower head 7 has an upper electrode made of a conductive material, and a plasma generation space P is formed below the shower head 7.

  In the lower part of the vacuum chamber 2, the electrostatic chuck 1 is installed at a position facing the shower head 7 with the plasma generation space P interposed therebetween. The electrostatic chuck 1 has an upper electrode of the shower head 7 and a lower electrode that forms an electrode pair for generating plasma. The lower electrode is installed in parallel with the upper electrode of the shower head 7 and is grounded. Further, substrate holding electrodes 9a and 9b surrounded by a dielectric material are disposed on the upper side of the lower electrode. The substrate holding electrodes 9a and 9b each have a flat plate shape and are disposed adjacent to each other, and are disposed in a direction parallel to the upper surface of the electrostatic chuck 1. When a voltage is applied to the substrate holding electrodes 9a and 9b from the substrate holding DC power supply 10, the substrate S disposed on the upper surface of the electrostatic chuck 1 is held by an electrostatic force. The electrostatic chuck 1 and the vacuum chamber 2 are electrically insulated from each other.

  The upper electrode of the shower head 1 is connected to a high frequency power source 11 through a shower head holding member 5. The high-frequency power source 11 is a power source that supplies power for generating plasma, and a known high-frequency power source used in a plasma processing apparatus can be used.

FIG. 2 shows the configuration of the electrostatic chuck 1. The electrostatic chuck 1 includes a laminated body of an upper plate 12, a heat fusion sheet 13 and a lower plate 14.
The upper plate 12 is made of a dielectric material and has substrate holding electrodes 9a and 9b therein. The substrate holding electrodes 9 a and 9 b are installed in parallel with the upper surface of the upper plate 12. As a material for forming the upper plate 12, for example, ceramics, polyimide, or the like can be used.
The lower plate 14 is formed of a conductive material and functions as a lower electrode that makes a pair with the upper electrode of the showerhead 7. As a material for forming the lower plate 14, for example, an aluminum alloy or the like can be used.

The heat-sealing sheet 13 is interposed between the upper plate 12 and the lower plate 14 and joined to each other by heat-sealing to electrically insulate the upper plate 12 and the lower plate 14 from each other and to have high dielectric breakdown resistance. It is formed from a fluoropolymer having properties. In such a heat-sealing sheet 13, the insulation is preferably 10 ¹⁶ Ωcm or more, the withstand voltage is preferably 10 kV or more, and the adhesiveness is preferably 1 kN / cm ² or more. As the fluorine-containing polymer forming the heat-fusible sheet 13, for example, a fluorine-containing ethylenic polymer having a hydroxyl group disclosed in Japanese Patent No. 3885805 can be used.

The upper plate 12, the heat fusion sheet 13, and the lower plate 14 are laminated and heated at 300 to 350 ° C. for 10 to 20 minutes, whereby the upper plate 12 and the lower plate 14 are connected to each other by the heat fusion sheet 13. Can be joined.
Thus, by joining the upper plate 12 and the lower plate 14 with the heat fusion sheet 13 having high dielectric breakdown resistance and bondability, labor and time associated with the manufacture of the electrostatic chuck 1 can be reduced. Can do.
In addition, the electrostatic chuck 1 heat-sealed in this way is heated at 300 to 350 ° C. in the same manner to melt or soften the heat-sealing sheet 13, so that the upper and lower plates 12 and 14 can The heat sealing sheet 13 can be removed.

  Next, the operation of the plasma processing apparatus provided with the electrostatic chuck 1 shown in FIG. 1 will be described.

First, the electrostatic chuck 1 composed of a laminate of the upper plate 12, the heat sealing sheet 13 and the lower plate 14 is fixed at a position facing the shower head 7 in the vacuum chamber 2 with the upper plate 12 as the upper surface. Is done. A substrate S is disposed at a predetermined position on the upper surface of the upper plate 12 of the electrostatic chuck 1, and a voltage is applied from the substrate holding DC power supply 10 to the substrate holding electrodes 9a and 9b. As a result, a positive potential and a negative potential are generated inside the upper plate 12, and an electrostatic force is generated between the substrate S and the dielectric-polarized substrate S, so that the substrate S is placed at a predetermined position on the upper plate 12. Retained.
Subsequently, the air in the vacuum chamber 2 is exhausted from the gas exhaust port 4 by the decompression device, and when the inside of the vacuum chamber 2 reaches a predetermined degree of vacuum, the reaction gas is supplied from the gas supply source to the gas supply chamber 6. The decompression device adjusts the exhaust in the vacuum chamber 2 and adjusts the vacuum chamber 2 to have a predetermined degree of vacuum even when the reaction gas is supplied.

The reaction gas supplied to the gas supply chamber 6 is ejected between the shower head 7 and the substrate S held by the electrostatic chuck 1 through a plurality of ejection holes 8 formed in the shower head 7. On the other hand, a voltage is applied to the shower head 7 from a high frequency power supply 11. As a result, an electrode pair is formed by the upper electrode of the shower head 7 and the lower plate 14 of the electrostatic chuck 1, and the reactive gas ejected between them is excited to generate plasma.
The surface of the substrate S is exposed to the plasma thus generated, and the substrate S is subjected to plasma treatment.

  Here, due to a temperature change caused by the generation of plasma, the shape of the upper plate 12 and the lower plate 14 of the electrostatic chuck 1 may change due to the difference in thermal expansion coefficient. However, by buffering the friction between the upper plate 12 and the lower plate 14, the generation of particles can be suppressed, and the quality of the plasma-treated surface can be improved.

When the plasma processing is completed, the next substrate S is held on the electrostatic chuck 1 and the same operation is repeated. Here, the upper plate 12 of the electrostatic chuck 1 may be unusable due to corrosion by plasma or malfunction of the electrodes 9a and 9b for electrostatic chuck. Even in such a case, the electrostatic chuck 1 can be regenerated by replacing only the unusable upper plate 12 with the peelable heat-sealing sheet 13 and reusing the usable lower plate 14. Can do.
For example, the electrostatic chuck 1 is removed from the vacuum chamber 2 and heat treatment is performed at 300 to 350 ° C. until the heat-sealing sheet 13 is melted or softened, thereby separating the upper plate 12 and the lower plate 14 from each other. Subsequently, the unusable upper plate 12 is replaced with a new one, and a new upper plate 12, a new heat-sealing sheet 13, and a washed lower plate 14 are stacked, and the upper plate 12 is heated at 300 to 350 ° C. The electrostatic chuck 1 is bonded after the heat treatment for ˜20 minutes is performed and the new upper plate 12 and the reused lower plate 14 are electrically insulated from each other by heat fusion of the heat fusion sheet 13. Can be played.
Even when the lower plate 14 of the electrostatic chuck 1 becomes unusable, only the lower plate 14 that has become unusable can be replaced and used by the heat-bondable sheet 13 that can be peeled off. The electrostatic chuck 1 can be regenerated by reusing the upper plate 12.

Thus, even if one of the upper plate 12 and the lower plate 14 constituting the electrostatic chuck 1 becomes unusable, the remnant of the heat-sealing sheet 13 attached to the other usable upper plate 12 or lower plate 14 The electrostatic chuck 1 can be reused by simply removing it by performing a simple process such as cleaning, and the electrostatic chuck 1 can be regenerated by a simple operation.
The other upper plate 12 or the lower plate 14 that can be used in the present embodiment is reused by washing, but the other upper plate 12 or the lower plate 14 can be used as a heat-sealing sheet 13 or the like. It is only necessary that the deposits can be removed. For example, the surface may be scraped or polished to be reused.

  The regenerated electrostatic chuck 1 is mounted in the vacuum chamber 2 and used in the same manner until one of the upper plate 12 and the lower plate 14 becomes unusable again.

  According to this embodiment, the upper plate 12 and the lower plate 14 are bonded by the heat-bonding sheet 13 having high dielectric breakdown resistance and bondability, thereby reducing labor and time associated with the manufacture of the electrostatic chuck 1. Can be achieved. Further, the heat-bonding sheet 13 can suppress the generation of particles by buffering the friction between the upper plate 12 and the lower plate 14, and the quality of the plasma-treated substrate S can be improved. Further, even if one of the upper plate 12 and the lower plate 14 constituting the electrostatic chuck 1 becomes unusable, the other upper plate 12 or the lower plate 14 that can be used can be reused only by performing a simple process such as cleaning. The electrostatic chuck 1 can be regenerated with a simple operation.

  Note that the lower plate 14 of the electrostatic chuck 1 is a substrate that is held on the upper surface of the upper plate 12 by incorporating a temperature adjusting unit 15 that includes at least one of a cooling device and a heating device, as shown in FIG. The temperature of S may be adjusted. The temperature from the cooling device and the heating device is transmitted from the lower plate 14 to the upper plate 12 through the heat-bonding sheet 13, but the heat-bonding sheet 13 formed from the fluoropolymer has a high thermal conductivity. Therefore, the temperature adjustment of the substrate S by the temperature adjustment unit 15 can be improved.

  In the present embodiment, the electrodes for holding the substrate S disposed on the upper surface of the electrostatic chuck 1 by electrostatic force use so-called bipolar type substrate holding electrodes 9a and 9b using two pairs of electrodes. As described above, a single-pole system having a single electrode on the upper plate 12 may be used.

  In this embodiment, the electrostatic chuck is used in a plasma processing apparatus that performs plasma processing on a substrate using a reactive gas. Similarly, the electrostatic chuck generates plasma and uses a source gas together with the reactive gas on a semiconductor substrate. The present invention can be similarly applied to a semiconductor manufacturing apparatus that performs film formation, and it becomes possible to form a high-quality film while suppressing generation of particles.

DESCRIPTION OF SYMBOLS 1 Electrostatic chuck, 2 Vacuum chamber, 3 Gas supply port, 4 Gas exhaust port, 5 Shower head holding member, 6 Gas supply chamber, 7 Shower head, 8 Ejection hole, 9a, 9b Substrate holding electrode, 10 Substrate holding DC power source, 11 high frequency power source, 12 upper plate, 13 heat fusion sheet, 14 lower plate, 15 temperature control unit, S substrate, P plasma generation space

Claims (5)

An electrostatic chuck for holding a substrate exposed to plasma by electrostatic force,
An upper plate having a substrate holding electrode for holding the substrate;
A lower plate having a plasma electrode for generating the plasma;
A heat composed of a fluorine-containing ethylenic polymer having a hydroxyl group and being joined between the upper plate and the lower plate in a state where the upper plate and the lower plate are electrically insulated from each other. An electrostatic chuck comprising a fusing sheet.   The electrostatic chuck according to claim 1, wherein the lower plate includes a temperature adjusting unit for adjusting a temperature of the substrate. A method of manufacturing an electrostatic chuck for holding a substrate exposed to plasma by electrostatic force,
An upper plate having a substrate holding electrode for holding the substrate and a lower plate having a plasma electrode for generating plasma are composed of a fluorine-containing ethylenic polymer having a hydroxyl group therebetween. Laminate with a heat-sealing sheet interposed,
An electrostatic chuck manufacturing method, wherein the upper plate and the lower plate are joined in a state of being electrically insulated from each other by heat fusion of the heat fusion sheet. A method for regenerating an electrostatic chuck for holding a substrate exposed to plasma by electrostatic force,
The electrostatic chuck is
An upper plate having a substrate holding electrode for holding the substrate;
A lower plate having a plasma electrode for generating the plasma;
A heat composed of a fluorine-containing ethylenic polymer having a hydroxyl group and being joined between the upper plate and the lower plate in a state where the upper plate and the lower plate are electrically insulated from each other. A fusion sheet and
Heating the used electrostatic chuck to melt or soften the thermal fusion sheet,
Separating the upper plate and the lower plate from each other;
Replace one of the upper plate and the lower plate with a new one and reuse the other,
A new heat-bonding sheet composed of a fluorine-containing ethylenic polymer having a hydroxyl group between the new upper plate or lower plate and the other upper plate or lower plate to be reused is interposed therebetween. Laminating,
The new one upper plate or lower plate and the other upper plate or lower plate to be reused are joined in a state of being electrically insulated from each other by heat fusion of the new heat fusion sheet. An electrostatic chuck regeneration method.   After the used electrostatic chuck is heated and separated into the upper plate and the lower plate, the other upper plate or lower plate to be reused is reused by cleaning, and the new one The electrostatic chuck regeneration method according to claim 4, wherein the electrostatic chuck is joined to the upper plate or the lower plate.

Images