JP3100236B2 - Plasma processing equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a plasma processing apparatus.

[0002]

2. Description of the Related Art In general, as a device for performing a part of a semiconductor manufacturing process, a plasma etching device for etching a wafer or the like to be processed under reduced pressure using active plasma is known. This type of etching apparatus is configured, for example, as shown in FIG. That is, a susceptor 4 insulated from the surroundings is disposed in a processing container 2 made of aluminum or the like, and a high-frequency power source 6 is applied to the susceptor 4 to form a lower electrode 8. A semiconductor wafer W is suction-held on the upper surface of the lower electrode 8 by an electrostatic chuck or the like, and plasma is generated between the upper electrode 10 and the lower electrode 8 using the ceiling of the processing container provided above as the upper electrode 10. Then, plasma processing is performed on the wafer W. At this time, by rotating the permanent magnet 12 provided above the processing chamber 2, a magnetic field is applied to the surface of the wafer W in the horizontal direction, and the activation of plasma is promoted. Further, for example, a ceramic heater 14 is provided in the upper electrode 10 so as to heat the upper electrode before and after the plasma processing or to control the temperature of the upper electrode during the plasma processing.

[0003]

From the viewpoint of improving productivity, for example, in the case of performing an etching treatment, it is preferable that the etching rate be as high as possible. Even if the object to be etched is a thermal oxide film or polycrystalline Si, the temperature difference between the upper electrode and the lower electrode and the respective set temperatures alone during the etching process is as small as possible. It is better to maintain the same temperature. Generally, during the plasma processing, the power of the heater 14 is reduced or cut off so that the upper and lower electrodes are maintained at a set temperature, for example, 60 ° C. As a result, for example, when the high-frequency power is 2 kW, the upper electrode temperature becomes 67 to 68 ° C.
This has the advantage that the temperature of the upper electrode rises to the extent that the upper electrode temperature cannot be maintained at an appropriate temperature.

In order to solve this problem, a cooling medium is circulated through the upper electrode 10 to cool it, but in this case, it takes time to conduct heat of the cooling heat of the cooling medium. For this reason, the thermal responsiveness is not sufficient, so that it is difficult to set and maintain the electrode at the specified temperature, and the temperature accuracy is not so good.
The present invention has been devised in view of the above problems and effectively solving them. SUMMARY OF THE INVENTION An object of the present invention is to provide a plasma processing apparatus capable of performing accurate temperature control by providing a heating means and a heat pipe on the upper electrode side.

[0005]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention provides a plasma processing apparatus for performing plasma processing on an object to be processed by plasma generated between an upper electrode and a lower electrode in a processing vessel. In the above, a heating means is formed above the upper electrode, a heat pipe for heat radiation is provided near the heating means, and air is blown to the heat pipe near the heat pipe.
And a heating fan to maintain the upper electrode at a predetermined temperature .
A control means for controlling the rotation is provided.

[0006]

According to the present invention, a heating means and a heat pipe for heat dissipation are provided on the upper electrode of the processing vessel, and the temperature of the upper electrode is controlled by a hot and cool method. The action of the heat pipe can promote heat radiation, make up for the insufficient amount of heat by controlling the amount of heat generated by the heating means using the control means , and rotate the blower fan.
Control the heat radiation of the heat pipe
Accordingly, it is an object of the present invention to provide a plasma processing apparatus capable of performing highly accurate temperature control.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the plasma processing apparatus according to the present invention will be described below in detail with reference to the accompanying drawings. FIG. 1 is a sectional view showing one embodiment of the plasma processing apparatus according to the present invention.
In this embodiment, a plasma etching apparatus will be described as an example of a plasma processing apparatus. The same parts as those of the conventional device shown in FIG. As shown in the figure, the plasma etching apparatus 16 is made of a material having good heat conductivity such as aluminum, for example, by 400 mm.
A processing container 2 formed in a rectangular shape having a rectangular shape, and a wafer mounting table made of, for example, aluminum or the like which is insulated from its surroundings for mounting, for example, a semiconductor wafer W as an object to be processed in the processing container 2 18 are installed.

The wafer mounting table 18 is composed of a susceptor 4 as an upper structure and a susceptor support table 20 for supporting the susceptor 4. An electrostatic chuck (not shown) is provided on the upper part of the susceptor 4, and the wafer W is attracted and held by a Coulomb force by applying a high DC voltage to the electrostatic chuck. The susceptor 4 is connected to a high-frequency power source 26 for plasma generation through a lead 22 via a matching 24 composed of a capacitor or the like, and is configured as a lower electrode 8. Further, the susceptor support 20 is provided with a cooling jacket 28 through which a coolant can flow, and the cooling jacket 28 can flow, for example, -50 ° C. florinate as a coolant and cool the wafer W by the cold heat. It has become.

The ceiling of the processing vessel 2 is formed in a parallel plate shape with respect to the susceptor 4 and is grounded, and is configured as an upper electrode 10. Therefore, a space between the upper electrode 10 and the lower electrode 8 is configured as a processing space,
The plasma processing is performed on the wafer W by generating plasma here. A processing gas introduction head 30 is provided over the entire lower surface of the upper electrode 10, and a large number of ejection holes 32 are formed on the lower surface thereof so as to face a lower processing space.
For example, a CF-based process gas introduced from the apparatus is released toward the processing space. And processing container 2
An exhaust pipe 36 provided with a vacuum pump (not shown) for evacuating the inside of the container is connected to the side wall 2.

The distance between the upper electrode 10 and the lower electrode 8 is generally set to a distance of, for example, about 10 to 25 mm. At the upper part of the upper electrode 10, a plate-like heating means at least larger than the wafer area, for example, a ceramic heater 14 is embedded and installed in aluminum so that the upper electrode 10 can be heated as required. It is composed of The amount of electric power supplied to the ceramic heater 14 is controlled by a control unit 36 as a control unit composed of, for example, a microcomputer for controlling the entire apparatus. In addition, a temperature detector 38 composed of a fluorooptic fiber thermometer or a thermocouple for measuring temperature using light is embedded in the upper electrode 10, and the output is input to the control unit 36. The above-mentioned fluorooptic fiber thermometer is a thermometer utilizing the fact that the round trip time of light changes depending on the temperature.

Above the upper electrode 10, that is, in the vicinity of the ceramic heater 14, there is provided a heat pipe 40 for radiating heat which has an area covering substantially the entire area of the electrode and is a feature of the present invention. Specifically, this heat pipe 40
Is formed as a rectangular cylinder having an operating space 42 inside, and the bottom, ceiling, and the entire wall of the pipe are made of a material having good heat conductivity, for example, aluminum. In the illustrated example, a state in which the bottom of the heat pipe 40 and the upper electrode 10 are integrally combined is shown.

The height L1 of the heat pipe 40 is set to, for example, several + mm. A proper amount of a working fluid 44 such as freon is accommodated in the inside of the heat pipe 40, and the inner wall surface and the inner surface of the ceiling are sponge. A wick 46, for example, such as a wire mesh, which absorbs the working fluid 42 well and causes a capillary phenomenon as shown in FIG. The lower portion of the heat pipe 40 is configured as an evaporator 40A for removing heat from the heater 14 and the lower electrode 8 to vaporize the working fluid 44, and the upper portion of the heat pipe 40 is configured to vaporize and evaporate the working fluid 44. Is configured as a condensing unit 40B for cooling and liquefying. In order to control the operation efficiency of the heat pipe 40, it is preferable to provide pressure adjusting means (not shown) for appropriately adjusting the pressure in the heat pipe 40. The ceramic heater 14 is controlled by the control unit 36, and is configured to adjust the amount of heat generated.

Further, on the side of the heat pipe 40,
A blower fan 48 is provided in close proximity thereto, and by blowing air from the blower fan 48 to the heat pipe 40, heat is radiated from the heat pipe to change the efficiency. The rotation speed of the blower fan 48 is controlled by controlling the drive motor 50 from the control unit 36. The working fluid 44 in the heat pipe 40, NH ₄ other freon described above, it is possible to use acetone, methanol, ethanol, heptane, and water. Further, as the wick 46, stainless steel wire mesh, nickel foam, metal wool, glass fiber, carbon fiber, ceramic fiber, or the like can be used. As a material of the heat pipe 40, stainless steel, copper, or the like can be used in addition to aluminum. A magnetic field generator 5 such as a permanent magnet is provided directly above the processing vessel 2.
2 and a drive motor 54 connected thereto.
Is rotated so that a horizontal rotating magnetic field is applied to the wafer W to increase the plasma processing efficiency.

Next, the operation of the embodiment constructed as described above will be described. In the present embodiment, as described above, the ceiling of the processing vessel 2 is grounded to form the upper electrode 10, and the high-frequency power source 6 is supplied to the susceptor 4 side to form a counter electrode, and the RIE (reactive ion) is performed.
(etching) type plasma etching apparatus. Further, the magnetron etching apparatus is rotated by rotating a magnetic field generator 52 composed of a permanent magnet above the processing container 2 at a position facing the wafer W to form a magnetic field parallel to the surface of the wafer W. Make up.
Then, an etching gas is introduced while the inside of the processing space is evacuated, and plasma is generated between the upper electrode 10 and the lower electrode 8 by the etching gas. Further, by forming a horizontal magnetic field in the vicinity of the wafer W, the flight direction of ions becomes perpendicular to the surface of the wafer W, and etching with high anisotropy can be realized. In this case, the inside of the processing container 2 is an exhaust pipe 36.
, For example, 10 ⁻² to 10 ⁻³ Torr
Pressure is maintained.

In this embodiment, in order to increase the etching rate and the production efficiency, the control unit 36 controls the high frequency power supply 2 so that the upper electrode 10 is maintained at, for example, + 60 ° C.
6. Control the amount of heat generated by the ceramic heater 14, the number of rotations of the blower fan 48, and the like. Before the plasma processing, the application of the high-frequency power supply 26 is stopped, and the driving of the blower fan 48 is stopped, and the temperature of the electrodes is maintained at about + 60 ° C. by the ceramic heater 14. In this state, the above-described plasma processing is performed by holding the wafer W by suction on the susceptor 4.

During the etching process, the upper electrode 1
Numeral 0 receives heat energy from the plasma and is heated to accumulate the heat energy. This heat evaporates and evaporates the working fluid 44 of the evaporating section 40A of the heat pipe 40, and the vapor rises in the heat pipe 40 The cooling fluid reaches the condensing section 40 serving as a ceiling, where the heat is radiated by the air blown from the blower fan 48 and the working fluid is condensed. This condensed working fluid 44
It is dropped from the condensing part 40B or flows down the inner wall of the pipe through the wick 46, reaches the evaporating part 40A again, and is vaporized again. Thus, the heat accumulated in the upper electrode 10 by the action of the working fluid 44 circulating the evaporation / condensation is efficiently removed.

Here, when plasma is generated by applying the high frequency power supply 26 to the electrodes, the power of the ceramic heater 14 is gradually reduced, and the heater 14 is controlled so that the upper electrode 10 maintains 60 ° C. In this case, if the heat pipe 40 is not used, even if the heater 14 is turned off, the upper electrode 10 becomes 6 due to accumulation of plasma heat.
Although the temperature rises to 7 to 68 ° C., the provision of the heat pipe 40 controls the power of the heater 14 and the number of rotations of the blower fan 48 while simultaneously radiating heat by the heat pipe 40 and heating by the heater 14.
Is maintained at + 60 ° C. As described above, when the temperature of the upper electrode is controlled while performing the heat radiation by the heat pipe and the heating by the heater 14 at the same time, the temperature of the electrode can be accurately controlled and maintained at a predetermined temperature.

That is, heat radiation is promoted by the action of the heat pipe 40, and the shortage of heat is compensated for by controlling the amount of heat generated by the ceramic heater 14 by the control unit 36, so that highly accurate temperature control can be performed. Therefore, since the temperature of the upper electrode 10 can be maintained at, for example, 60 ° C., the etching rate can be maintained at a high level. In the actual control, when the electrode temperature is set to 60 ° C., the blower fan 48 is configured to radiate the excess temperature increase, for example, 6 to 7 ° C. or more to the atmosphere by the heat pipe 40.
To control the number of revolutions.

In the above embodiment, the blower fan 48
Although only one unit is provided, a plurality of units may be provided at appropriate intervals along the circumferential direction of the heat pipe 40. Further, as shown in FIG. 2, a large number of heat radiating pipes or heat radiating fins 56 may be provided on the ceiling of the heat pipe 40 so as to protrude upward from the ceiling in a sealed state to increase the heat radiating efficiency. Further, in the above embodiment, the description has been made by taking the plasma etching apparatus as an example, but the present invention is not limited to this.
Of course, the present invention can be applied to a D apparatus, a plasma sputtering apparatus, and the like.

[0020]

As described above, according to the plasma processing apparatus of the present invention, the following excellent functions and effects can be exhibited. The temperature of the upper electrode is controlled by using both the heating by the heating means and the heat radiation by the heat pipe ,
Moreover, the heat pipe is controlled by controlling the rotation speed of the blower fan.
Since the heat radiation amount is also controlled, the temperature of the upper electrode can be controlled accurately and at a predetermined temperature.

[Brief description of the drawings]

FIG. 1 is a sectional view showing one embodiment of a plasma processing apparatus according to the present invention.

FIG. 2 is a sectional view showing another embodiment of the plasma processing apparatus according to the present invention.

FIG. 3 is a cross-sectional view illustrating an example of a conventional plasma processing apparatus.

[Explanation of symbols]

 2 Processing Vessel 4 Susceptor 8 Lower Electrode 10 Upper Electrode 14 Ceramic Heater (Heating Means) 16 Plasma Etching Apparatus (Plasma Processing Apparatus) 26 High Frequency Power Supply 36 Control Unit (Control Means) 38 Temperature Detector 40 Heat Pipe 44 Working Fluid 46 Wick W Semiconductor wafer (workpiece)

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-4-181724 (JP, A) JP-A 1-211921 (JP, A) JP-A-63-115338 (JP, A) JP-A-62-162 12129 (JP, A) JP-A-61-105097 (JP, A) JP-A-1-248623 (JP, A) JP-A-60-76032 (JP, U) (58) Fields investigated (Int. Cl. ⁷ , DB name) H01L 21/3065 C23C 14/34 C23C 16/505

Claims (5)

(57) [Claims] 1. A plasma processing apparatus for performing a plasma process on an object to be processed by plasma generated between an upper electrode and a lower electrode in a processing vessel, wherein a heating means is formed above the upper electrode. A heat pipe for radiating heat is provided near the heat pipe, a blower fan for blowing air is provided near the heat pipe, and a heating value of the heating means and rotation of the blower fan to maintain the upper electrode at a predetermined temperature. A plasma processing apparatus provided with control means for controlling the temperature. 2. The heat pipe is installed above the heating means, and an inner surface of the heat pipe includes:
Claim 1 Symbol placement of the plasma processing apparatus wherein the wick to cause the capillary phenomenon is formed by absorbing the internal working fluid. 3. The heat pipe according to claim 1, wherein the heat pipe has an area covering substantially the entire area of the upper electrode.
Or the plasma processing apparatus according to 2. The method according to claim 4, wherein the heat pipe, the plasma processing apparatus according to any one of claims 1 to 3, characterized in that heat radiation fins for promoting heat dissipation is provided. 5. The control means stops the blower fan before the plasma processing, maintains the upper electrode at substantially the processing temperature by the heating means, and drives the blower fan after the plasma processing starts to drive the upper electrode. the plasma processing apparatus according to any one of claims 1 to 4, wherein the controller controls so as to maintain the electrodes in substantially the processing temperature.