JPH11233602A - Electrostatic chucking apparatus and apparatus for processing sample using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To ensure the reliability of electric terminals for applying a voltage to electrodes by embedding the electric terminals electrically insulated from a first electrode in a through-hole at a recess of an Al head, connecting the electrical terminal to a second electrode, and forming a dielectric film on the surfaces of the first and second electrodes. SOLUTION: An insulator 21 is provided on a screw-fixed grounding board 20 in a vacuum chamber, a lower electrode is provided on the top of the insulator 21, an Al head 24 is mounted on its surface, a circular groove 31 is provided as a recess at the Al head 24, a through-hole 32 is bored through one spot of the groove 31, an insulator 33 is embedded in the through-hole 32, a second electrode 35 is embedded in the insulator 33 so as to project from the bottom of the groove 31 and electrically connected to an electrical terminal 29, an insulation film 34 is provided in the groove 31, a first electrode 30 is formed on its surface, and a dielectric film 23 is formed on the surfaces of the first and second electrodes 30, 35 through the melt spraying.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrostatic suction apparatus and a sample processing apparatus, and more particularly to a wafer processing apparatus which is used for fixing a wafer in a semiconductor manufacturing apparatus at the time of transferring or processing the wafer and utilizing electrostatic force. The present invention relates to an electrostatic suction device and a sample processing device suitable for holding.

[0002]

2. Description of the Related Art A method of holding an object using static electricity is used particularly for transferring a wafer in a semiconductor manufacturing apparatus and fixing the wafer during each process. As a holding method for carrying or fixing the wafer, a mechanical holding method using a clamp or the like can be considered, but using an electrostatic force has many advantages in holding the semiconductor wafer. For example, there is no mechanical contact with the processing surface of the wafer, so there is no contamination of the wafer by abrasion powder, etc. Is more reliable, the thermal conductivity is improved, and the temperature control of the wafer becomes easier. As described above, electrostatic attraction has many advantages as a method for holding a wafer, and is therefore widely applied particularly as a wafer processing electrode in an apparatus such as dry etcher or CVD.

In an electrostatic chuck, an electrostatic attraction force is generated by the electrostatic force of the electric charge stored in the dielectric film and the electric charge polarized near the rear surface of the wafer, so that a potential difference is generated between the dielectric film and the wafer. Therefore, it is necessary to apply a high DC voltage of about several kilovolts or less. Therefore,
If the electrical connection of the voltage supply portion to the electrodes is not secure, abnormal discharge or disconnection may occur, causing a problem that an attraction force cannot be generated.

A method for dealing with such a problem is disclosed, for example, in Japanese Patent Laid-Open No. 6-342843. In this disclosure, a method is shown in which a screw hole is provided in a voltage supply portion of an electrode, a bolt structure is adopted for an electrical contact, and connection is performed by screw fastening.

[0005]

However, in the above method, the thickness of the electrode provided with the dielectric film is limited only to a case where the thickness is sufficient to provide the screw holes. For example, there is a problem that the method cannot be applied to a case where a dielectric film is provided on the surface of a conductive material and another very thin electrode is embedded in the dielectric film.

SUMMARY OF THE INVENTION It is an object of the present invention to provide an electrostatic chuck having extremely high reliability of an electric terminal for applying a voltage to an electrode.

It is a second object of the present invention to provide an electrostatic attraction device in which the electrodes of the electrostatic attraction device can be easily connected to an external power supply.

It is a third object of the present invention to provide a highly reliable sample processing apparatus for a sample holding unit in a sample processing apparatus.

[0009]

A first object of the present invention is to provide a first electrode made of a conductive material with a recess for arranging a second electrode, and penetrating at least one of the recesses. A hole is provided, an electric terminal is buried in the through hole while being electrically insulated from the first electrode, and a second electrode is provided in the concave portion so as to be electrically connected to the electric terminal. This can be achieved by forming a dielectric film on the surface of the two electrodes by thermal spraying.

A second object of the present invention is to provide a structure in which a socket portion is provided at one end of the electric terminal opposite to the side on which the dielectric film is formed, and electricity is supplied to the socket portion from an external power supply. Can be achieved.

Further, the third object of the present invention can be achieved by applying the electrostatic suction device according to the present invention to a sample holding section of a sample processing device.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings.

FIGS. 1 to 3 show a first embodiment of the present invention, in which the present invention is applied to a magnetic field microwave plasma processing apparatus.
FIG. 1 is a schematic cross-sectional view of the electrostatic chuck of the first embodiment of the present invention, and FIG. 2 is a cross-sectional view of the case where the electrostatic chuck of the first embodiment is applied to a processing apparatus. . First, the configuration and operation of the apparatus will be briefly described with reference to FIG.

A quartz tube 14 is set in the atmospheric pressure space 3, and a wafer 9 is fixed in a vacuum processing chamber 1 using the electrostatic chuck 8. The electrostatic attraction device of the present invention is applied to the electrostatic attraction device 8, which will be described later in detail. First,
A processing gas 13 is introduced into the vacuum processing chamber 1. The processing gas is
The interaction between the microwave 5 generated by the microwave oscillator 19 and introduced through the waveguide 4 and the magnetic field of the coil 6 attached around the discharge tube 2 results in a plasma state 7. The processing (here, etching processing) is performed by exposing the wafer to this plasma. In particular, the high frequency power supply 10 connected via the capacitor 18 controls the etching state by controlling the incidence of ions. The application of a voltage to the electrostatic attraction device is performed by a DC power supply 11 via a switch 12, and the electrodes in the electrostatic attraction device can be grounded 16 by switching the switch. Reference numeral 17 denotes a coil for preventing a high frequency component from flowing. Reference numeral 15 denotes an exhaust port for excess processing gas and reaction products, which is connected to a vacuum pump (not shown here).

Next, the electrostatic attraction device 8 of this embodiment will be described in detail with reference to FIGS. Electrostatic suction device 8
Has a four-layer structure as shown in FIG. First, an earth plate 20 screwed (not shown) is provided in a vacuum chamber, and an insulating material 21 for insulating the electrostatic chuck and the earth plate is provided thereon. An aluminum lower electrode 22 is provided above the insulating material 21. And
An aluminum head 24 having a dielectric film 23 formed by spraying ceramics on the surface is mounted on the lower electrode 22. These ground plate 20, insulating material 21, lower electrode 22
Is provided with a through hole 25, and an insulating guide 26 is further inserted into the through hole 25. Power is supplied to the embedded electrode 30 accommodated in the aluminum head 24 by a current introduction terminal 29 having a lead wire 38 therein.
8 is fixed to the ground plate 20.

A circumferential groove 31 is provided in the aluminum head 24, and a through hole 32 is formed in one place of the groove. An insulating material 33 is embedded in the through hole 32. The insulating material is fixed to the aluminum head with an adhesive. A buried metal 35 made of tungsten is buried in the insulating material 33 and protrudes from the bottom of the groove 31. Further, an insulating film 34 is applied to the groove 31 by thermal spraying such that one end of the buried metal 35 appears on the surface. A buried electrode 30 made of tungsten is formed on the surface of the insulating film 34 by spraying to have a thickness of 100 μm, and conduction with the buried electrode 35 is established. These aluminum head 24, insulating film 34, embedded electrode 30
Is sprayed on the surface of the dielectric film 23, and the surface of the dielectric film 23 is polished to a flat surface. In this embodiment, in order to further enhance the insulating effect between the aluminum head 24 serving as the first electrode and the embedded electrode 30 serving as the second electrode, before spraying the embedded electrode 30 onto the insulating film 34,
The groove is provided by the thickness of the embedded electrode. When a potential difference is applied between the embedded electrode and the aluminum head in this state,
Since the bipolar electrostatic chucking circuit is formed, it is possible to suck the object to be sucked loaded on the surface of the dielectric film.

In the thus formed electrostatic chuck, the electrodes of the electrostatic chuck (embedded electrodes 30 in this embodiment) are used.
And the buried metal 35 for supplying voltage is connected by thermal spraying of the same metal, so that conduction is ensured. Therefore, even when a high voltage is applied, disconnection and abnormal discharge can be prevented, and A highly reliable electrostatic attraction device is obtained. Further, it is possible to provide a structure that can ensure conduction even when the embedded electrode 30 is extremely thin. In this case, although not applied in this embodiment, when the aluminum head is cooled to control the temperature of the wafer, the second electrode (embedded electrode 30) is very thin and can be sufficiently cooled. The effect can be expected.

FIGS. 4 and 5 show a second embodiment of the present invention. In this embodiment, one end of the buried metal of the first embodiment on the lower electrode side has a socket structure. One end of the current introduction terminal 36 is configured to engage with the socket.

With the electrostatic suction device configured as described above, the same effect as that described in the first embodiment can be expected.
Since it is very easy to connect the component having the dielectric film and the component to which the component having the dielectric film is attached, there is an advantage that the time for the replacement operation or the like can be reduced.

In this embodiment, one end of the buried metal has a socket structure. However, the same effect can be obtained if the structure on the side of the current introducing terminal is a socket structure.

[0021]

According to the present invention, it is possible to provide an electrostatic chuck having extremely high reliability of the electric terminal for applying a voltage to the electrode. Further, it is possible to provide an electrostatic attraction device in which the electrodes of the electrostatic attraction device and the external power supply are very easily connected.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view schematically showing a first embodiment of the electrostatic suction device of the present invention.

FIG. 2 is a cross-sectional view when the electrostatic suction device of FIG. 1 of the present invention is applied to a processing apparatus.

FIG. 3 is a cross-sectional view of the case where the electrostatic suction device of FIG. 2 of the present invention is applied to a magnetic field microwave processing device.

FIG. 4 is a sectional view schematically showing a second embodiment of the electrostatic chuck according to the present invention.

5 is a cross-sectional view of the case where the electrostatic suction device of FIG. 4 of the present invention is applied to a processing apparatus.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Vacuum processing chamber, 2 ... Discharge tube, 3 ... Atmospheric space, 4 ... Waveguide, 5 ... Microwave, 6 ... Coil, 7 ... Plasma, 8 ...
Electrostatic chuck, 9 wafer, 10 high frequency power supply, 11
DC power supply, 12 switch, 13 processing gas, 14 quartz tube, 15 exhaust port, 16 ground, 17 coil, 18
... condenser, 19 ... microwave transmitter, 20 ... ground plate, 21 ... insulating material, 22 ... lower electrode, 23 ... dielectric film, 2
4 ... aluminum head, 25 ... through hole, 26 ... insulation guide,
27 ... O-ring, 28 ... Volt, 29 ... Current introduction terminal,
Reference numeral 30: embedded electrode, 31: groove, 32: through hole, 33:
Insulating material, 34: insulating film, 35: embedded metal, 36: current introduction terminal, 37: socket, 38: lead wire.

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Saburo Kanai 794, Higashi-Toyoi, Katsumatsu-shi, Kamamatsu-shi, Yamaguchi Prefecture Inside the Kasado Plant of Hitachi, Ltd. Inside the Kasado Plant of Hitachi, Ltd.

Claims (6)

[Claims] A first electrode formed of a conductive material and a recess for arranging a second electrode, wherein at least one of the recesses is provided;
A through hole is provided at a location, an electric terminal is buried in the through hole while being electrically insulated from the first electrode, and the second electrode is provided in the recess so as to be electrically connected to the electric terminal. ,
A dielectric film formed by spraying on the surfaces of the first electrode and the second electrode, and a potential difference is applied between the first electrode and the second electrode to be placed on the dielectric film. An electrostatic attraction device, which is capable of electrostatically attracting. 2. The electrostatic attraction device according to claim 1, wherein
An electrostatic attraction device, wherein the connection between the second electrode and the electric terminal is made with a conductive adhesive. 3. The electrostatic attraction device according to claim 1, wherein
An electrostatic attraction device, wherein the second electrode is formed by thermal spraying. 4. The electrostatic attraction device according to claim 3, wherein
An electrostatic attraction device wherein the material of the second electrode and the electric terminal is formed of the same material. 5. The electrostatic chuck according to claim 1, wherein a socket portion is provided at one end of the electric terminal opposite to the side on which the dielectric film is formed, and the socket portion receives electricity from an external power supply. An electrostatic attraction device characterized by supplying. 6. A sample processing apparatus comprising the electrostatic attraction device according to claim 1.