JP3736103B2 - Plasma processing apparatus and processing method thereof - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a plasma processing apparatus such as a dry etching apparatus, a sputtering apparatus, and a CVD apparatus used for manufacturing a semiconductor device, a liquid crystal display (LCD), and the like, and a processing method thereof .
[0002]
[Prior art]
In recent years, when plasma processing is performed on a substrate to be processed such as a silicon substrate, a plasma processing apparatus that uses a means for cooling or heating the substrate to stabilize the processing temperature has been used.
[0003]
Hereinafter, a conventional plasma processing apparatus will be described.
FIG. 2 shows a cross section of a conventional plasma processing apparatus. In FIG. 2, 21 is a processing tank, 22 is an evacuation pump, 23 is an upper electrode having a reactive gas outlet, and the upper electrode 23 is grounded by a ground 24. Reference numeral 25 denotes a substrate to be processed such as a silicon substrate or a glass substrate, 26 denotes a convex lower electrode, and the surface of the lower electrode 26 is covered with an insulating film 27. The lower electrode 26 is placed on an insulating plate 28 and connected to a high frequency power source 29.
[0004]
A heat transfer gas supply port 30 is provided at the center of the lower electrode 26, and a cooling water pipe 31 is provided inside the lower electrode 26 to circulate the cooling water. A clamp ring 32 is provided around the lower electrode 26.
[0005]
The operation of the plasma processing apparatus configured as described above will be described below.
[0006]
First, the substrate 25 to be processed is placed on the lower electrode 26, and the substrate 25 to be processed and the lower electrode 26 are brought into close contact with the clamp ring 32. Next, after the processing tank 21 is evacuated by the vacuum pump 22, the reaction gas is introduced into the processing tank 21, helium gas is supplied from the heat transfer gas supply port 30, and the space between the substrate 25 and the lower electrode 26 is processed. To charge. Next, plasma is generated between the lower electrode 26 and the upper electrode 23 by applying high frequency power from a high frequency power source 29. At this time, since the atmosphere becomes high due to the generation of plasma, the substrate to be processed 25 is heated. However, the temperature of the lower electrode 26 is constantly controlled by the cooling water in the pipe 31, and the heat of the substrate 25 to be processed is transmitted to the lower electrode 26 by the helium gas having excellent thermal conductivity. The temperature of 25 is kept constant.
[0007]
[Problems to be solved by the invention]
However, in the above-described conventional configuration, the substrate to be processed 25 that is insulative and floating with respect to the lower electrode 26 due to the insulation of the insulating film 27 accumulates electric charges due to the generation of plasma, and has a potential of −300 to −400V. It becomes. At this time, since there is a space filled with helium gas at a constant pressure in the heat transfer gas supply port 30, the substrate 25 to be processed charged to a negative potential and the lower electrode to which the high frequency power of the high frequency power source 29 is applied. An abnormal discharge occurs between the substrate 26 and the substrate to be processed 25, which is damaged.
[0008]
The present invention solves the above-described conventional problems, and an object thereof is to provide a plasma processing apparatus that prevents abnormal discharge between a substrate to be processed and an electrode.
[0009]
[Means for Solving the Problems]
In order to achieve this object, a plasma processing apparatus and a processing method thereof according to the present invention include a first electrode provided in a processing tank and having a surface covered with an insulating film, and a first electrode provided in the processing tank. and second electrode, that is provided in the center of the substrate clamping means for securing an end of the substrate to be processed on the first electrode in a state where the arched central portion of the substrate, the first electrode And a heat transfer gas supply port for supplying a heat transfer gas to a space between the first electrode configured by warpage of the substrate to be processed and the substrate to be processed, and the first electrode or Plasma is generated by supplying high-frequency power to any of the second electrodes . Further, the heat transfer gas is supplied to the space through a porous insulator embedded in the heat transfer gas supply port.
[0010]
With this configuration, the heat transfer gas supply port can be electrically insulated, and abnormal discharge between the lower electrode and the substrate to be processed can be prevented.
[0011]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, an embodiment of the present invention will be described with reference to the drawings.
[0012]
FIG. 1 is a view showing a cross section of a plasma processing apparatus according to an embodiment of the present invention. In FIG. 1, 1 is a treatment tank, 2 is an evacuation pump, 3 is an upper electrode having a reactive gas outlet, and the upper electrode 3 is grounded by a ground 4. 5 is a silicon substrate as a substrate to be processed, 6 is a convex lower electrode, and the surface of the lower electrode 6 is covered with an insulating film 7. The lower electrode 6 is placed on the insulating plate 8 and is electrically connected to the high frequency power source 9. A heat transfer gas supply port 10 is provided at the center of the lower electrode 6, and a porous insulator 11 having air permeability such as ceramics is embedded in the heat transfer gas supply port 10. Inside the lower electrode 6 is a cooling water pipe 12 through which cooling water circulates. A clamp ring 13 is provided around the lower electrode 6, and the clamp ring 13 is fixed on the lower electrode 6 with the silicon substrate 5 being warped.
[0013]
The operation of the plasma processing apparatus configured as described above will be described.
First, the silicon substrate 5 is warped by the clamp ring 13 and fixed on the lower electrode 6 so that a space is generated between the silicon substrate 5 and the lower electrode 6. Next, after the inside of the processing tank 1 is evacuated by the vacuum pump 2, the reaction gas is introduced into the processing tank 1 from the reaction gas outlet of the upper electrode 3. Further, helium gas (heat transfer gas) is supplied through the porous insulator 11 of the heat transfer gas supply port 10 to fill the space between the silicon substrate 5 and the lower electrode 6 with helium gas. Next, high frequency power from a high frequency power source 9 is applied to the lower electrode 6 to generate plasma between the lower electrode 6 and the upper electrode 3. At this time, the silicon substrate 5 is heated by the generation of plasma, but the heat of the silicon substrate 5 is transmitted to the lower electrode by helium gas having excellent thermal conductivity. Further, the temperature of the lower electrode 6 is controlled to be constant with cooling water that circulates in the pipe 12. Therefore, even if the ambient temperature rises due to plasma generation, the silicon substrate 5 can keep the temperature constant.
[0014]
According to this configuration, electrical insulation between the silicon substrate 5 and the lower electrode 6 is achieved by the insulating film 7 coated on the surface of the lower electrode 6 and the porous insulation embedded in the heat transfer gas supply port 10. The abnormal discharge between the back surface of the silicon substrate 5 and the lower electrode 6 can be prevented.
[0015]
【The invention's effect】
As described above, the plasma processing apparatus and the processing method according to the present invention supply the heat transfer gas through the porous insulator embedded in the heat transfer gas supply port of the lower electrode. Insulation of the substrate is improved, abnormal discharge between the back surface of the substrate to be processed and the lower electrode can be prevented, and the temperature of the substrate to be processed can be kept constant, and plasma processing can be performed stably.
[Brief description of the drawings]
FIG. 1 is a sectional view of a plasma processing apparatus according to an embodiment of the present invention. FIG. 2 is a longitudinal sectional view of a conventional plasma processing apparatus.
DESCRIPTION OF SYMBOLS 1 Processing tank 2 Vacuum exhaust pump 3 Upper electrode 4 Ground 5 Silicon substrate 6 Lower electrode 7 Insulating film 8 Insulating plate 9 High frequency power supply 10 Heat transfer gas supply port 11 Porous insulator 12 Cooling water piping 13 Clamp ring

Claims (2)

A first electrode provided inside the processing tank and having a surface covered with an insulating film, a second electrode provided inside the processing tank, and the substrate to be processed in a state where the central portion of the substrate to be processed is warped. wherein a substrate clamping means for securing an end of the substrate on the first electrode, provided in the center portion of the first electrode Rutotomoni, the said first electrode constituted by the flexure of the substrate to be processed A heat transfer gas supply port for supplying a heat transfer gas to a space between the substrate to be processed and generating high-frequency power to either the first electrode or the second electrode to generate plasma a plasma processing apparatus,
A plasma processing apparatus, wherein a heat transfer gas is supplied to the space through a porous insulator embedded in the heat transfer gas supply port. A first electrode provided inside the processing tank and having a surface covered with an insulating film, a second electrode provided inside the processing tank, and the substrate to be processed in a state where the central portion of the substrate to be processed is warped. The edge of the substrate 1 A substrate clamping means for fixing on the first electrode, and a space between the first electrode and the substrate to be processed, which is provided at the center of the first electrode and is configured by warping of the substrate to be processed. A processing method of a plasma processing apparatus, comprising a heat transfer gas supply port for supplying a heat transfer gas, and generating plasma by supplying high-frequency power to either the first electrode or the second electrode. ,
A plasma processing method, wherein a heat transfer gas is supplied to the space through a porous insulator embedded in the heat transfer gas supply port.

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