JPH03102820A - Vacuum treating apparatus - Google Patents

Abstract

PURPOSE:To obtain thermal conduction of ten times or higher as compared with a conventional method by providing an electrostatic attraction unit and a cooling gas pipe for introducing pressure controlled cooling gas between a first electrode and a substrate. CONSTITUTION:An electrostatic attraction unit 7 is formed of an insulator 9 and electrostatic attraction electrodes 10, and a DC power source 11 for applying a high voltage is connected to the electrodes 10. The upper end of a cooling gas pipe 12 passing through the center between a first electrode 1 and the unit 7 is opened between the contact faces of the electrodes 10 and a material 8 to be treated. The unit 7 is operated by the source 11 to electrostatically attract the material 8, reactive gas is introduced into a vacuum vessel 3 through a gas introduction tube 5, and cooling gas controlled at its temperature is introduced between the contact faces of the unit 7 and the material 8 through the pipe 12. When an AC power source 4 is energized in this state, reactive gas existing between the first electrode 1 and a second electrode 2 is excited to produce plasma for etching the surface of the material 8. The temperature of the material 8 is extremely lowered, and its temperature control is improved by about ten times.

Description

[Detailed Description of the Invention] [Object of the Invention] (Industrial Field of Application) The present invention relates to a vacuum processing apparatus that performs etching processing, etc. on a processing target such as a semiconductor wafer board in a high vacuum while controlling the temperature. In particular, the present invention relates to a vacuum processing apparatus having a temperature control mechanism that combines an electrostatic adsorption method and a gas cooling system using heat conduction of gas.

(Prior Art) For example, in a vacuum processing apparatus used for dry etching, a reactive gas is supplied onto a substrate such as a silicon wafer, and etching is performed using a chemical reaction or a physical reaction.

In this dry etching method, the substrate temperature greatly affects the etched shape and selectivity, so highly accurate temperature control is required. However, in conventional methods, substrate temperature control involves heating the electrode stage on which the substrate is placed, This was simply done by cooling.

(Problems to be Solved by the Invention) In the substrate temperature control method by heating and cooling the electrode stage described above, the temperature control characteristics are poor because the substrate temperature depends on the heat conduction at the contact portion between the electrode stage and the substrate. However, there were problems with the etching shape and selectivity.

[Structure of the invention]

(Means for Solving the Problems) In order to achieve the above object, the vacuum processing apparatus of the present invention includes a 17l5 pole and a second electrode arranged oppositely in a vacuum container, and a reactive gas injected into the vacuum container. An electrostatic adsorption device that electrostatically adsorbs a workpiece (substrate) to the first electrode in a vacuum processing apparatus comprising a reactive gas supply device that supplies a flood of reactive gas, and a vacuum evacuation device that evacuates the inside of the vacuum container. and a cooling gas pipe for introducing pressure-controlled cooling gas between the first electrode and the substrate.

(Function) In the vacuum processing apparatus of the present invention configured as described above, the substrate placed on the electrode stage (first electrode) at a temperature of J3 increases the number of contact parts with the electrode stage by electrostatic adsorption. Furthermore, by supplying gas to the non-contact portion, heat conduction that is 10 times or more can be obtained compared to conventional methods. Also,
When the cooling gas supplied between the electrode stage and the substrate is gas-sealed by the ring-shaped protrusion, it is possible to prevent the cooling gas from leaking into the processing atmosphere.

(Example) Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 schematically shows the main parts of the vacuum processing apparatus of the present invention, in which a first electrode 1 and a second electrode 2 are arranged facing each other in a vacuum container 3 with a predetermined interval in the vertical direction. ing.

The first electrode 1 is grounded via an AC power source 4, and the second electrode 1 is grounded via an AC power source 4.
m-pole 2 is directly grounded.

A gas introduction pipe 5 for introducing a reactive gas and a gas exhaust pipe 6 for evacuating the reactive gas are attached to the side wall of the vacuum container 3. A reactive gas supply device (not shown) is connected to the gas introduction pipe 5, and a vacuum evacuation device (not shown) for evacuating the inside of the vacuum container 3 is connected to the gas exhaust pipe 6.

Cooling water maintained at a constant temperature flows through the first electrode 1 via a piping system (not shown), and the first electrode 1 is maintained at a predetermined temperature.

A workpiece 8 such as a wafer 7 or a substrate is electrostatically attracted to the upper surface of the first electrode 1 via an electrostatic attraction device 7 .

As the details of the electrostatic adsorption device 7 are shown in FIG. A high voltage is applied to the direct f? tPower supply] 1 is connected.

The upper end of a cooling gas pipe 12 that penetrates through the center of the first electrode 1 and the electrostatic chucking device 7 is open between the contact surface between the electrostatic chucking electrode 10 and the object to be processed 8 .

A pressure-controlled cooling gas is supplied to this cooling gas pipe through a gas introduction pipe 13.

In the vacuum processing apparatus of the present invention configured as described above,
The electrostatic adsorption device 7 is operated by the DC power source 11 to electrostatically adsorb the object 8 to be processed, and after introducing a reactive gas into the vacuum container 3 via the gas introduction n5, the reactive gas is introduced into the vacuum container 3 via the cooling gas pipe 12. Then, a temperature-controlled cooling gas is introduced between the contact surface between the electrostatic adsorption device 7- and the workpiece 8.

In this state, when the AC power source 4 is turned on, the reactive gas interposed between the first electrode 1 and the second electrode 2 is excited, turns into plasma, and etches the surface of the object 8 to be processed.

FIG. 3 shows the temperature of the object to be processed (wafer substrate) 8 during plasma processing by the apparatus of the present invention having the above configuration, and curve A shows the temperature of the object to be processed (wafer substrate) 8 when the object to be processed 8 is simply placed on the electrostatic adsorption device 7. Curve B shows the case where the object to be processed 8 is simply adsorbed by the electrostatic adsorption device 7. In addition, curve C represents the object to be processed 8.
A case is shown in which the electrostatic adsorption device 7 adsorbs the liquid and gas cooling is used in combination. As is clear from this figure, according to the present invention, the temperature of the object to be processed 8 is significantly lowered, and the temperature control is also improved by about 10 times.

FIG. 4 shows another embodiment of the present invention, in which a ring-shaped protrusion 9a having a diameter slightly smaller than the diameter of the limb treatment object is formed on the upper surface of the insulator 9 of the electrostatic adsorption device 7.

In this way, the sealing function between the electrostatic adsorption device 7 and the object to be processed 8 is improved, so that the amount of leakage of cooling gas can be significantly reduced.

That is, in the case of FIG. 2, the amount of cooling gas leakage is 5. OX10
It is about **pam*/see, but in the case of FIG. 3, it is about 3.2X10**pam*/sec, which makes it possible to reduce it to about 1/100 or less.

〔Effect of the invention〕

As described above, according to the vacuum processing apparatus of the present invention, the object to be processed placed on the temperature-controlled first electrode can increase the contact area with the first electrode by electrostatic adsorption, and moreover, the non-contact area can be increased. By supplying a pressure-controlled cooling gas, more than 10 times the heat transfer can be obtained compared to conventional methods. Also,
When the cooling gas supplied between the electrode stage and the substrate is sealed by the ring-shaped protrusion, the cooling gas can be prevented from leaking into the processing atmosphere.

Figure 2 is a block diagram of the vicinity of the electrostatic chuck device in the apparatus of the present invention, Figure 3 is a graph showing the relationship between processing time and substrate temperature using a cooling method, and Figure 4 is a diagram showing the electrostatic chuck device and other parts in the apparatus of the present invention. FIG.

DESCRIPTION OF SYMBOLS 1... First electrode, 2... Second electrode, 3... Vacuum container, 4... AC power supply, 5... Gas introduction tube, 6...
Gas outlet pipe, 7... Electrostatic adsorption device, 8... Treated object, 9... Insulator, 9a... Ring-shaped protrusion, 10.
...Electrostatic adsorption electrode, 11...DC power supply, 12...
Cooling gas piping, 13... gas introduction pipe.

Claims (1)

[Claims] A first electrode and a second electrode arranged opposite each other in a vacuum container, a reactive gas supply device for supplying a reactive gas into the vacuum container, and a vacuum evacuation device to evacuate the inside of the vacuum container. In the vacuum processing apparatus, an electrostatic adsorption device that electrostatically adsorbs a workpiece to the first electrode; a cooling gas pipe that introduces pressure-controlled cooling gas between the first electrode and the workpiece; A vacuum processing apparatus comprising: