JPH11265879A - Vacuum processing equipment - Google Patents

Abstract

PROBLEM TO BE SOLVED: To restrain dust from attaching to a pressure ring so as to carry out an etching process well by a method wherein a graphite ring of excellent thermal conductivity is provided in the upper periphery of an electrode holder, and a heat-resistant sheet is interposed between the graphite ring and a substrate pressure ring. SOLUTION: A lower electrode 11 is arranged putting its base on bases 20 located on the base of a vacuum chamber 1 and fixed by the side with holders 21, and a heat dissipating outer ring 24 of single crystal graphite is provided in the upside periphery of the holders 21. A substrate 18 to process is fixed to the lower electrode 11 with a doughnut-shaped pressure ring 22 located on the upside of the dissipating outer ring 24, and a heat-resistant sheet 25 is interposed between the outer ring 24 and the pressure ring 22. When the surface of the substrate 18 is subjected to etching, a certain amount of reactive gas is supplied into the vacuum chamber 1 after the substrate 18 is fixed to the lower electrode 11, a high-frequency electrode 12 and a matching equipment 13 are operated to generate plasma, and the substrate 18 is exposed to plasma.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to a vacuum processing apparatus used for manufacturing electronic devices such as semiconductor chips and liquid crystal panels.

[0002]

2. Description of the Related Art Conventionally, as a means for patterning various thin films constituting various electronic devices into a desired shape, a wet etching method in which a substrate provided with an etch mask is immersed in an etching solution, or a substrate provided with a metal mask is used. A dry etching method or the like in which the substrate is placed in a vacuum chamber and irradiated with plasma, ions, or the like is used. In recent years, with the miniaturization of electronic devices, the pattern shape of various thin films has become extremely fine, and the use of dry etching, which has higher processing accuracy than wet etching, has become the mainstream.

FIG. 2 is a sectional view showing a schematic configuration of an example of a vacuum processing apparatus for dry etching. 1 shows a vacuum chamber. The vacuum chamber 1 has a substrate insertion port 2 for inserting a substrate by a manipulator or the like, a gas supply port 4 for supplying a reaction gas by opening and closing a valve 3 connected to a reaction gas tank (not shown), and a vacuum pump. 5
An exhaust port 9 is provided which is connected to the valves 6 and 6 to adjust the pressure in the vacuum chamber 1 by opening and closing the valves 7 and 8. The vacuum chamber 1 communicates with a preliminary exhaust chamber (not shown) through a door of the substrate insertion port 2. An upper electrode 10 is provided on the upper surface of the vacuum chamber 1, and a lower electrode 11 held as described below is provided opposite to the upper electrode 10. A high frequency power supply 12 for applying a high frequency voltage between the two electrodes and a matching device 13
Is connected.

The lower electrode 11 is fixed on a base 20 at the bottom of the vacuum chamber 1 by a holder 21 which presses the bottom from the base. On the lower electrode 11,
A substrate 18 to be processed is installed and fixed by a donut-shaped pressing ring 22 that can be moved up and down by an arm (not shown). An electric shield plate 23 is provided on the outer periphery of the base 20 and the holder 21 to shield discharge from the lower electrode 11. The base 20, the holder 21, and the pressing ring 22 are made of ceramic, and the upper and lower electrodes are made of aluminum. The lower electrode 11 is provided with a cooling water circulation path 14 therein, and is maintained at a desired temperature by flowing cooling water whose temperature is controlled by a temperature controller (not shown). A tube 1 penetrating near the center of the lower electrode 11
6, 17 are valves 15 connected to the helium gas tank,
Each is connected to a valve 19 connected to the vacuum pump 5. By opening and closing the valves 15 and 19, a helium gas layer is formed between the substrate 18 and the lower electrode 11, thereby suppressing an increase in the substrate temperature during plasma etching.

[0005] Using the vacuum processing apparatus having such a configuration,
In order to etch the substrate surface, the substrate 18 is placed in the preliminary exhaust chamber, the chamber is evacuated, the door of the substrate insertion port 2 is opened, and the substrate 18 is removed using a manipulator or the like (not shown). It is inserted into the vacuum chamber 1. Then, the arm is moved to lift the pressing ring 22, and the substrate 18 is placed on the lower electrode 11. Subsequently, the pressing ring 22 is lowered to fix the substrate 18 on the lower electrode 11. Next, the valve 3 is opened to supply a certain amount of the reaction gas into the vacuum chamber 1 from the gas supply port 4, and the valves 6 and 7 are opened and closed to adjust the inside of the vacuum chamber 1 to a desired pressure state. Then, the high frequency power supply 12 and the matching device 13 are operated to apply a high frequency voltage between the upper electrode 10 and the lower electrode 11 to generate plasma. Substrate 1
The substrate surface is etched by exposing 8. At this time, the valves 15 and 19 are opened to suppress a rise in the substrate temperature. After the etching process, the substrate is pushed up above the lower electrode by closing the valve 3, raising the pressing ring 22, and raising the pin (not shown) housed in the lower electrode 11. Then, open the door of the substrate entrance 2,
The substrate is taken out to the preliminary exhaust chamber with the substrate sandwiched between manipulators or the like.

[0006]

In the vacuum processing apparatus having the above-described structure, the vicinity of the inner periphery of the pressing ring 22 includes heat generated on the surface of the substrate 18 and electrons existing in the plasma.
The temperature rises due to collisions of radicals and ions.
However, since the outer peripheral portion of the pressing ring 22 does not have such an effect, the temperature hardly increases and the temperature is low. As described above, since the outer peripheral portion of the pressing ring 22 is at a low temperature, the reaction product released into the vacuum adheres and accumulates on the outer peripheral portion of the pressing ring 22 to form a dust lump. This dust mass,
Due to the vertical movement of the pressing ring 22 when the substrate 18 is set, the pressing ring 22 drops from the pressing ring 22 and adheres to the substrate to be processed.

[0007] Since the dust mass adhering to the substrate 18 forms a place like a mask which is not etched, the substrate surface cannot be patterned into a desired shape, which is a factor of causing a pattern defect. . Also,
Even in a vacuum film forming apparatus having a configuration similar to that of the above vacuum processing apparatus, the dust mass forms a portion where a film is not formed or remains as a foreign substance in the thin film. Had been lowered. In view of the above problems, an object of the present invention is to provide a vacuum processing apparatus capable of suppressing dust from adhering to a pressing ring and performing favorable etching processing and forming a thin film.

[0008]

According to the present invention, there is provided a vacuum processing apparatus comprising: a reaction chamber having a gas supply port and an exhaust port; a means for adjusting atmospheric gas and pressure in the reaction chamber; a lower electrode having a cooling water circulation path therein; An electrode holder that presses and fixes the lower electrode from the side to the bottom of the reaction chamber, an upper electrode that faces the lower electrode, a power supply that applies a voltage between the two electrodes, and a peripheral portion of the substrate to be processed. A substrate pressing ring to be fixed on the lower electrode is provided, and a graphite ring having good thermal conductivity is provided on the peripheral edge of the upper surface of the electrode holder, and a heat-resistant sheet is provided between the graphite ring and the substrate pressing ring. It is characterized by intervening.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS As described above, the vacuum processing apparatus according to the present invention is provided with a heat radiation outer peripheral ring having excellent heat conductivity at the periphery of an upper surface of an electrode holder for holding a lower electrode. It is configured to efficiently transmit the heat of the substrate to the peripheral portion of the substrate pressing ring. With such a configuration, the temperature of the peripheral portion of the substrate pressing ring can be increased, so that the reaction product can be prevented from adhering to the peripheral portion of the substrate pressing ring. As a result, a dust lump is less likely to be formed, and the dust lump does not drop onto the substrate.

It is preferable to use single-crystal graphite having excellent thermal conductivity for the heat-radiating outer peripheral ring. This single-crystal graphite has anisotropy in its thermal conductivity, and therefore needs to be installed in consideration of the direction of the layer surface. Further, a heat-resistant thin sheet such as a polyimide sheet is provided between the heat-radiating outer peripheral ring and the substrate to be processed so that the substrate is not contaminated with graphite carbon. As the heat-resistant sheet, a thin sheet that does not hinder heat transfer is used. As a vacuum processing apparatus, in addition to an etching apparatus such as a parallel plate type reactive ion etching apparatus, the present invention is applied to a film forming apparatus for forming a thin film on a substrate by a sputtering method or a chemical vapor deposition method (CVD method). be able to.

FIG. 1 is a sectional view showing a schematic configuration of an example of a vacuum processing apparatus according to the present invention. As in FIG. 2, the vacuum chamber 1 is provided with a substrate insertion port 2, a gas supply port 4 connected to the valve 3, and an exhaust port 9 connected to the valves 7 and 8. Valves 7 and 8 are connected to vacuum pumps 4 and 5. An upper electrode 10 and a lower electrode 11 held as described below are installed in the vacuum chamber 1, and a high-frequency power supply 12 for applying a high-frequency voltage and a matching device 13 are connected between the two electrodes.

The lower electrode 11 is mounted on a base 20 at the bottom of the vacuum chamber 1, and is fixed from the side by a holder 21. At the periphery of the upper surface of the holder 21, a heat-radiating outer peripheral ring 24 made of single-crystal graphite is provided. A donut-shaped pressing ring 22 for fixing the substrate 18 to be processed on the lower electrode 11 is provided on the upper surface of the outer peripheral ring 24.
And a heat-resistant sheet 25 is interposed between them. An electric shield plate 23 is provided on the outer periphery of the base 20 and the outer ring 24 to shield discharge from the lower electrode 11. The lower electrode 11 is maintained at a desired temperature by controlling the temperature of the cooling water flowing through the cooling water circulation path 14 provided inside.

In order to etch the surface of the substrate using the vacuum apparatus having such a configuration, the substrate 18 is fixed on the lower electrode 11 and the reaction gas is introduced into the vacuum chamber 1 in the same manner as in FIG. A fixed amount is supplied, the high-frequency power supply 12 and the matching machine 13 are operated to generate plasma, and the substrate is exposed to the plasma. At this time, the peripheral edge of the pressing ring 22 is warmed by the heat transmitted through the heat-radiating outer peripheral ring 24, and the entire surface of the pressing ring 22 has substantially the same temperature.
After the etching, the substrate 18 is taken out in the same manner as in FIG.

[0014]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in more detail by applying the apparatus having the structure shown in FIG. 1 to a parallel plate type reactive ion etching apparatus. The outer ring 24 was made of single crystal graphite, and had a thermal conductivity of 800 W / (m · K) from the electrode holder 21 to the pressing ring 22. As the heat-resistant sheet 25, a polyimide sheet having a thickness of 0.03 mm was used. First, by circulating water kept at 75 ° C. through the cooling water circulation path 14, the temperature of the lower electrode 11 becomes 7 ° C.
The temperature was controlled to be 5 ° C. Then, when the surface temperature of the pressing ring 22 was measured using a thermo label, it was maintained at about 60 ° C. in any place.

Next, a polysilicon film was formed on the surface.
An inch silicon wafer was prepared, and the wafer was evacuated in the pre-evacuation chamber, then put into the vacuum chamber 1 through the substrate insertion port 2, and the pressing ring 22 was lowered and fixed. Then, the valve 3 was opened, a mixed gas of Cl ₂ and HBr was supplied into the vacuum chamber 1, and the valves 7 and 8 were opened and closed to adjust the internal pressure to about 50 Pa. Subsequently, a high-frequency voltage of 400 W was applied between the upper and lower electrodes to etch the polysilicon film. After that, the press ring was raised, the etched substrate was taken out from the substrate insertion port 2, and the next wafer prepared by vacuuming in the preliminary exhaust chamber was inserted. Even when this operation was repeated 300 times, no adhesion or deposition of the reaction product on the pressing ring 22 was observed.

[0016]

As described above, according to the present invention, a thin film on a substrate can be faithfully etched according to a resist pattern,
A good thin film containing no dust can be formed.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view showing a schematic configuration of a vacuum processing apparatus according to an embodiment of the present invention.

FIG. 2 is a longitudinal sectional view showing a schematic configuration of a conventional vacuum processing apparatus.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Upper electrode 11 Lower electrode 18 Substrate 20 Base 21 Electrode holder 22 Substrate pressing ring 23 Electric shield plate 24 Graphite ring 25 Heat resistant sheet

Claims (1)

[Claims] 1. A reaction chamber having a gas supply port and an exhaust port, means for adjusting the atmospheric gas and pressure in the reaction chamber,
A lower electrode having a cooling water circulation path therein, an electrode holder for pressing and fixing the lower electrode from the side to the bottom of the reaction chamber, an upper electrode facing the lower electrode, a power supply device for applying a voltage between the two electrodes, And a substrate pressing ring for pressing the substrate to be processed and pressing the peripheral portion thereof on the lower electrode, and a graphite ring having good thermal conductivity is provided on a peripheral portion of the upper surface of the electrode holder, and the graphite ring and the substrate are provided. A vacuum processing apparatus comprising a heat-resistant sheet interposed between the pressure ring and a pressure ring.