JPH0220369B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to an electrostatic chuck device, and more particularly to an electrostatic chuck device that facilitates the removal of objects to be treated.

[Technical background of the invention]

BACKGROUND ART In recent years, semiconductor manufacturing processes have rapidly become dry and automated, and with this, production equipment with high precision and high mass productivity has been actively developed. Further, in semiconductor integrated circuits, the miniaturization of elements has progressed, and recently, ultra-LSIs with minimum dimensions of 1 to 1.5 [μm] have been prototyped. It is no exaggeration to say that the ultimate yield of these ultrafine devices is determined by the fight against dust on the micron order during the production process, and therefore production equipment must be structured to prevent dust as much as possible. I have no choice but to do so.

The most effective method for preventing dust is to process the object with the device-forming surface facing its own weight. In order to realize this method, a means for fixing the object to be processed on the stage with its processing side facing down is required, and furthermore, this fixing means itself must not become a source of dust. In addition, production equipment includes equipment that processes objects by irradiating them with charged beams such as ion beams and electron beams, such as dry etching equipment that uses high-frequency discharge, ion implantation equipment, electron beam lithography equipment, and electron beam annealing equipment. In many cases, such as a device, it is necessary to maintain sufficient thermal contact between the stage and the workpiece in order to sufficiently suppress the temperature rise of the workpiece, and a uniform chucking force is required. For the above purpose, electrostatic chuck devices have recently been attracting attention.

Incidentally, as a semiconductor processing apparatus, for example, a reactive ion etching apparatus, equipped with the above-mentioned electrostatic chuck apparatus, a structure shown in FIG. 3 is conventionally known. That is, 1 in the figure is a conductive vacuum chamber with an open top surface, and this chamber 1 is grounded. An electrostatic chuck plate (electrode) 3 is disposed on the upper surface of the chamber 1 via an insulating material 2 such as fluororesin, and a dielectric film 4 made of polyimide or the like is disposed on the lower surface of the electrode 3. It is pasted. A conduit 5 that also serves as a water cooling pipe is installed inside the electrode 3. One end of the conduit 5 is connected to a high frequency power source 7 via a matching circuit 6, and the other end is connected to a DC power source 9 via a choke coil 8 for cutting off high frequency waves. The electrode 3 and the dielectric film 4 are provided with a through hole 10 penetrating them, as shown in FIG. 4, and an insulating pipe 11 is attached to the through hole 10 via a flange. There is. This piping 11
is branched in the middle, and one branch pipe 12a
is connected to a gas supply source, and the other branch pipe 12b is connected to an exhaust system. In addition, these branch pipes 1
Electromagnetic valves 13a and 13b are inserted into 2a and 12b, respectively.

A gas introduction pipe 14 and an exhaust pipe 15 are attached to the lower surface of the chamber 1, respectively. Also,
A bearing 18 that pivotally supports the shaft 17 of the air cylinder 16 is provided in the center of the lower surface of the chamber 1 so as to pass through the chamber 1 . A support stand 19 is arranged at the upper end of the shaft 17. This support stand 19 includes a plate body 20 fixed to the shaft 17, a receiving plate 21 on which the object to be processed is placed, and is attached to the lower surface of this receiving plate 21 with its lower end penetrating the plate body 20.
It is comprised of a support shaft 23 on which a coil spring 22 is wound between a plate body 20 and a receiving plate 21.

Next, the operation of the reactive ion etching apparatus having the electrostatic chuck device having the structure shown in FIGS. 3 and 4 will be explained.

First, the receiving plate 2 of the support stand 19 in the vacuum chamber 1
1, a workpiece 24 such as a wafer is installed. Subsequently, the support table 19 is raised by the air cylinder 16, and the dielectric film 4 on the lower surface of the electrode 3 to which a DC voltage is applied from the DC power source 9 is brought into contact with the object to be processed 24, and the object to be processed is moved by the electrostatic force. 24 as dielectric film 4
Fix it by suction. At this time, the electrode 3 and the dielectric film 4
The through hole 10 penetrated by the object 24 is closed by the object 24, and the electromagnetic valve 13b is opened to evacuate the gas inside the through hole 10 from the branch pipe 12b to prevent electrical discharge on the back surface of the object 24. I'm trying to prevent it.

Next, the gas in the chamber 1 is exhausted from the exhaust pipe 15, and a gas such as Ar is supplied from the gas introduction pipe 14 to create a gas atmosphere in the chamber 1 at a predetermined pressure. In this state, by turning on the high frequency power supply 7, plasma is generated between the electrode 3 and the support base 19 at ground potential, and ions in the plasma collide with the object 24 to be processed. Etching is performed on the lower surface (front surface) side. Further, the electrode 3 and the object to be processed 24 are cooled by the cooling water flowing inside the conduit 5.

After etching is completed, the high-frequency electrode 7 is turned off and the DC electrode 9 is turned off, and then the support base 19, which is at ground potential, is raised by the air cylinder 16, brought into contact with the object to be processed 24, and accumulated on the object to be processed 24. The generated charges are released through the support base 19. Thereafter, the electromagnetic valve 13b is closed, and the electromagnetic valve 13a is opened for a certain period of time to blow gas such as N ₂ directly onto the back surface of the object to be processed 24 from the branch space 12a. As a result, the electrostatically chucked object 24 is detached from the lower surface of the electrode 3 and placed on the receiving plate 21 of the support base 19. On the other hand, apart from the conventional example,
Japanese Patent Publication No. 78641 discloses a technique for detaching the object to be treated using a piston driven by gas pressure control.

[Problems with background technology]

However, this type of device has the following problems. That is, in the former case, the object to be processed 2
Since gas is directly blown onto the workpiece 24 through the through hole 10 in order to remove the In addition, there was a problem in that the object 24 to be processed was damaged. In addition, in the latter case, since it has a flow control valve that gradually sends pressurized air to the air cylinder that drives the piston, the configuration is complicated and the air cylinder is large, which makes it difficult to Since it protrudes from the bottom of the electric chuck base, there is a problem in that the size of the device itself becomes large.

[Purpose of the invention]

The present invention was made in consideration of the above circumstances, and
The purpose is to create a compact electrostatic chuck device that can reliably detach the electrostatically chucked workpiece and prevent damage to the workpiece due to changes in gas pressure, etc. Our goal is to provide the following.

[Summary of the invention]

The gist of the present invention is to use a piston driven by gas pressure as a buffer member when the object to be processed is detached from the chuck electrode by gas pressure.

That is, the present invention provides an electrode that electrostatically attracts and fixes an object to be processed, an accommodating section formed inside the electrode with one side opening to the adsorption surface of the object, and an accommodating section connected to the other side of the accommodating section. a piping, a piston provided in the storage section that is driven in a direction to press the object to be processed, an elastic body that biases the piston in a direction opposite to the object to be processed, and an elastic body that is wound around the piston and is driven in a direction that presses the object to be processed. A piston ring made of an elastic body that moves integrally with the piston in close contact with the inner surface of the storage section, and a gas supply device that supplies gas to the storage section through the piping when the object to be processed is removed. The structure is designed to provide the following features.

[Embodiments of the invention]

Hereinafter, details of the present invention will be explained with reference to illustrated embodiments.

FIG. 1 is a schematic configuration diagram showing a reactive ion etching apparatus using an electrostatic chuck device according to an embodiment of the present invention, and FIG. 2 is an enlarged sectional view showing the configuration of the main parts of the apparatus. Note that the same parts as in FIGS. 3 and 4 are designated by the same reference numerals, and detailed explanation thereof will be omitted.

This embodiment differs from the conventional device described above in that a housing part 30 is formed inside the chuck electrode instead of a through hole, and a piston is provided in this housing part 30. That is, the chuck electrode 3
In the accommodating part 30 which is formed penetrating the dielectric film 4 and has one side open to the adsorption surface of the object to be treated, it is made of ceramic such as SiO ₂ or Al ₂ O ₃ or SUS or Al.
It has a structure in which a piston 25 made of metal such as the like is embedded with a spring (elastic body) 26 interposed therebetween. Here, the piston 25 is arranged to be slidable in the vertical direction, and is pressed upward by a spring 26. The piston 25 also includes a piston ring (O-ring) made of an elastic material such as rubber.
27 is wrapped. This O-ring is in the housing part 3.
0 so as to move together with the piston 25 in close contact with the inner surface of the piston 25. In the figure, 28 indicates a gasket, and 29 indicates a lid.

Although not shown, the other side of the housing section 30 is connected to a gas introduction pipe 14 connected to a supply device.

In such a configuration, after the reactive ion etching is finished, the high frequency power source 7 is turned off, and the DC power source 9 is turned off, the support base 1 at the ground potential is turned off.
9 is raised by an air cylinder 16 and brought into contact with the object 24 to be processed, and the charge accumulated on the object 24 is released through the support table 19. Next, the solenoid valve 13b is closed, and the solenoid valve 13a is opened for a certain period of time to introduce gas such as N ₂ from the branch pipe 12a, and the pressure causes the piston 25 to resist the pressing force of the spring 26 and the frictional resistance of the O-ring 27. The object to be processed is moved forward in the direction of the object 24. As a result, the electrostatically chucked object 24 can be gently detached from the lower surface of the electrode 3, and the object 24 can be placed on the receiving plate 21 of the support stand 19. Note that by exhausting the air using the solenoid valve 13b, the piston 25 is returned to its original position by the spring 26.

According to this embodiment, the supporting table 19 at ground potential is brought into contact with the electrostatically chucked workpiece 24, and the piston 25 is moved toward the workpiece by supplying gas from the pipe 11. Accordingly, the object to be processed 24 can be gently detached from the electrode 3 from the lower surface side. And in this case,
When supplying N ₂ gas, even if the introduced pressure fluctuates greatly, the spring 26 and piston ring 27 act as a damper, so that no sudden damage is caused to the object 24 to be processed. Also, piston 25
Since the driving distance of the piston 25 is regulated by the flange portion and the spring 26, the protrusion length of the piston 25 is constant no matter how high the gas pressure becomes, so there is a risk of extra action other than detachment. There isn't. In other words, the electrostatically chucked workpiece 24
can be reliably desorbed, and damage to the object to be processed 24 due to changes in gas pressure or the like can be prevented.

Note that the present invention is not limited to the embodiments described above. For example, the chuck electrode is
The electrode is not limited to one that also serves as an electrode for applying high-frequency power, and may be provided separately and below the electrode for applying high-frequency power. Further, instead of the spring (coil spring) that biases the piston, a leaf spring or other elastic body may be used. In addition to reactive ion etching equipment, we also offer sputtering equipment, plasma CVD equipment, and
For ion implantation equipment, electron beam lithography equipment, etc.
Of course, it can also be applied in the same way. In addition, various modifications can be made without departing from the gist of the present invention.

〔Effect of the invention〕

As described in detail above, according to the present invention, when the object to be processed is detached from the chuck electrode by gas pressure,
It has a simple and compact structure that uses a piston driven by gas pressure, and has an elastic body and a piston ring made of an elastic body added to the piston to control the drive, so even if the gas pressure fluctuates greatly, it will not be applied to the processed material. Inconveniences such as a sudden increase in pressing force were eliminated, and the electrostatically chucked workpiece could be reliably removed without damaging the workpiece.

[Brief explanation of drawings]

FIG. 1 is a schematic configuration diagram showing a reactive ion etching apparatus using an electrostatic chuck device according to an embodiment of the present invention, FIG. The figure is a schematic configuration diagram showing a conventional reactive ion etching device.
FIG. 2 is a cross-sectional view showing an enlarged configuration of main parts of the device shown in the figure. DESCRIPTION OF SYMBOLS 1... Vacuum chamber, 3... Electrostatic chuck plate (electrode for chuck), 4... Dielectric film, 5... Conduit, 7... High frequency power supply, 9... DC power supply, 10...
...Through hole, 11...Piping, 12a, 12b...Branch pipe, 16...Air cylinder, 19...Support stand, 24...Workpiece, 25...Piston, 26
... Spring (elastic body), 27 ... Piston ring, 30 ... Accommodation section.

Claims (1)

[Scope of Claims] 1. An electrode that electrostatically adsorbs and fixes the object to be treated;
A housing part formed inside the electrode and having one side open to the suction surface of the object to be treated, a pipe connected to the other side of the housing part, and a pipe provided in the housing part and driven in a direction to press the object to be treated. an elastic body that urges the piston in a direction opposite to the object to be processed; and an elastic body that is wound around the piston and moves integrally with the piston in close contact with the inner surface of the housing section. An electrostatic chuck device comprising: a piston ring; and a gas supply device that supplies gas to the storage section via the piping when the object to be processed is removed. 2. The electrostatic chuck device according to claim 1, wherein the electrode is also used as a processing electrode to which high frequency power or the like is applied for surface treatment of the object to be processed.