JP2007115883A - Substrate treatment equipment - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide substrate treatment equipment suppressing an eddy current flowing through a soaking pipe fitted between an electrode for applying a high frequency and a heater for a heating, and being capable of effectively converting a charged high-frequency power to a plasma. <P>SOLUTION: The substrate treatment equipment has a treating pipe 2 forming a space housing a substrate, the soaking pipe 16 arranged so as to coat the treating pipe 2 from the outside, and a heating means 4 arranged around the soaking pipe 16. The substrate treatment equipment further has a pair of the electrodes 6 and 7 arranged in the space between the treating pipe 2 and the soaking pipe 16 for receiving the application of the high-frequency power. Irregularities are formed to a surface on at least the electrode side of the soaking pipe 16. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a substrate processing apparatus, and more particularly to a plasma processing apparatus that performs predetermined substrate processing using plasma generated by high-frequency power.

  For example, in the manufacture of semiconductor integrated circuits, plasma is used to promote ionization, chemical reaction, and the like of process gases in CVD, etching, ashing, and sputtering processes. Conventionally, methods for generating plasma in a semiconductor manufacturing apparatus include a parallel plate method, a high frequency induction method, a helicon wave method, and an ECR method. The parallel plate method is a method of generating plasma between both electrodes by grounding one of a pair of parallel plate electrodes and capacitively coupling the other to a high frequency power source. The high frequency induction method is a method of generating plasma by applying a high frequency to a spiral or spiral antenna to create a high frequency electromagnetic field and causing electrons flowing in the electromagnetic field space to collide with neutral particles in the gas. The helicon wave method generates a special electromagnetic wave (helicon wave) that travels parallel to the magnetic field by a specially shaped antenna within a uniform magnetic field made of coils, and uses the Landau damping effect associated with this helicon wave to create a velocity. In this method, plasma is generated by a controllable electron flow. In the ECR method, a microwave having a frequency equal to the cyclotron frequency of an electron (2.45 GHz) is guided through a waveguide in a uniform magnetic field formed by a coil, and a resonance phenomenon is caused. In this method, plasma is generated by absorption. As these plasma generation methods, there are a single-wafer method for processing the objects to be processed one by one and a method for processing a plurality of objects to be processed in batches.

  In the conventional plasma processing apparatus, a heater is provided outside the processing tube so that the inside of the processing tube can be heated. In addition, a high-frequency application electrode for generating plasma by applying high-frequency power is provided between the processing tube and the heater. A soaking tube is provided between the high-frequency applying electrode and the heater so as not to cause a significant temperature difference in the substrate to be processed.

  In such a device, the magnetic field generated by the current flowing through the high-frequency application electrode penetrates the soaking tube, eddy current flows through the soaking tube, and Joule heat is generated due to the inherent resistance value of the soaking tube and eddy current, There is a problem that the input high frequency power (RF power) is not effectively converted into plasma.

  Therefore, a main object of the present invention is to provide a substrate processing apparatus capable of suppressing eddy current flowing in a soaking tube and effectively converting inputted high-frequency power into plasma.

According to the present invention,
A processing tube forming a space for accommodating the substrate;
A soaking tube arranged to cover the processing tube from the outside;
Heating means disposed around the soaking tube;
Arranged in a space between the processing tube and the soaking tube, and comprising at least a pair of electrodes to which high-frequency power is applied,
A substrate processing apparatus is provided in which an uneven portion is provided on at least the surface of the soaking tube on the electrode side.

  ADVANTAGE OF THE INVENTION According to this invention, the substrate processing apparatus which suppresses the eddy current which flows into a soaking | uniform-heating tube, and can convert the input high frequency electric power into plasma effectively is provided.

  Next, a preferred embodiment of the present invention will be described.

  In a preferred embodiment of the present invention, in a batch type plasma processing apparatus in which a processing tube and a soaking tube are installed, and an electrode is placed between the processing tube and the soaking tube, and a high frequency power is applied thereto to generate plasma. The soaking tube has a double structure.

  Further, in a preferred embodiment of the present invention, a batch type plasma processing apparatus in which a processing tube and a soaking tube are installed, an electrode is placed between the processing tube and the soaking tube, and high frequency power is applied thereto to generate plasma. , The inner and outer double-layer soaking pipes constituting the soaking pipe are provided with pores, and the inner and outer soaking pipes are configured so as not to communicate with each other. Blocking the space.

  Further, in a preferred embodiment of the present invention, a batch type plasma processing apparatus in which a processing tube and a soaking tube are installed, an electrode is placed between the processing tube and the soaking tube, and high frequency power is applied thereto to generate plasma. However, the inner and outer heat equalizing tubes are electrically connected to each other through contact resistance, and the contact resistance is higher than that of the integrally molded product.

  Next, preferred embodiments of the present invention will be described in more detail with reference to the drawings.

  FIG. 1 shows the configuration and arrangement of electrodes and heat equalizing tubes placed on the outer surface of the processing chamber 1, FIG. 2 shows a cross section of the processing chamber 1, and FIG. 3 shows a cross section of the processing chamber as viewed from above. It is.

  The processing chamber 1 is hermetically configured with a processing tube 2 and a seal cap 3, and a heater 4 is provided around the processing tube 2 so as to surround the processing chamber 1. The processing tube 2 is made of a dielectric material such as quartz, and a first electrode 6 (6a to 6h) connected to the high frequency power source 5 and a second electrode 7 (7a) connected to the ground are provided on the outer periphery of the processing tube 2. ˜7h) are alternately arranged in stripes perpendicular to the object to be processed (semiconductor wafer in this embodiment) 8. As the high frequency (RF) power, AC power output from the high frequency power source 5 can be applied to the first electrode 6 via the matching unit 9. The frequency of AC power supplied to the first electrode 6 is often 13.56 MHz.

  The processing chamber 1 is connected to a pump 12 via an exhaust pipe 10 and a pressure adjustment valve 11 so that the gas inside the processing chamber 1 can be exhausted. Further, the processing chamber 1 is provided with a gas introduction port 13, which is provided along a side surface inside the processing chamber 1, for supplying a plurality of gases whose sizes are adjusted so as to supply the processing gas evenly in the height direction. The gas can be introduced uniformly by the gas supply nozzle 14 provided with the pores 25.

  Inside the processing chamber 1, a boat 15 that can be horizontally mounted, for example, about 100 to 150, is provided so that semiconductor wafers that are also the workpieces 8 can be batch-processed.

  A soaking tube 16 is installed between the heater 4 and the processing tube 2 so that a significant temperature difference does not occur in the workpiece 8. Even if the heat distribution of the heater 4 is non-uniform, the soaking tube 16 becomes a thermal warming medium and does not give a significant temperature difference to the workpiece 8. The soaking tube 16 is made of SiC. Since SiC is excellent in heat conduction, the temperature distribution of the workpiece 8 can be made more uniform.

  In this embodiment, the soaking tube 16 has a double structure, and pores are provided to block the eddy current path so that the RF power is efficiently converted into plasma. Since the eddy current has a property of flowing more on the surface, in addition to providing a pore in the inner tube of the double heat equalizing tube, providing a pore in the outer tube in order to prevent it from flowing around the outer tube, and The inner tube and the outer tube are fitted together without being integrally molded, and the resistance is increased by contact resistance.

  As shown in FIG. 5, when the electrode 6 (7) is positioned in the vicinity of the SiC soaking tube 16, as shown in FIG. 4, a magnetic field 32 is generated by the current flowing through the electrode 6 (7). This magnetic field 32 penetrates the soaking tube 16, and an eddy current 33 flows on the surface of the soaking tube. The eddy currents 33 are combined to form a combined eddy current 34. Accordingly, Joule heat is generated by the resistance value of the soaking tube 16 and the eddy current 33.

  In the research of the present inventors, it has been found that heating of the soaking tube by such eddy current (induction heating) is extremely disadvantageous for plasma generation. That is, a part of the input RF power is not converted into plasma and is used for heating the soaking tube, so that there is a problem that the input high frequency power cannot be effectively converted into plasma.

  It is assumed that the eddy current flows as shown in FIG. Therefore, in order to prevent the eddy current, it is necessary to increase the equivalent resistance value of the soaking tube 16.

  It is known that eddy currents tend to flow on the surface. In general, the depth δ at which the eddy current enters is expressed by the following equation.

  Here, ρ represents the resistivity (μΩcm) of the member, μ represents the relative permeability of the member, and f represents the frequency (Hz).

  In the case of the present embodiment, it is about 3 mm. In addition, this penetration depth means the place where the value becomes 1 / e compared with the surface current. Moreover, the thickness of the soaking tube 16 is usually 5 to 10 mm.

  Further, the influence of such an eddy current is greater on the surface of the soaking tube 16 on the side of the electrodes 6 and 7 than on the surface on the side opposite to the electrodes 6 and 7.

  Therefore, in order to suppress the influence of the eddy current, an uneven portion is provided on the surface of at least the electrode 6 (7) side of the soaking tube 16. If it does in this way, the extended surface distance of the surface of the soaking tube 16 becomes long, resistance value can be raised and eddy current can be reduced.

  More preferably, a concavo-convex portion is also provided on the surface of the heat equalizing tube 16 opposite to the electrode 6 (7). At this time, it is preferable that the uneven portion on the surface on the electrode 6 (7) side and the uneven portion on the surface opposite to the electrode 6 (7) do not overlap each other. If they overlap, a through hole is formed in the soaking tube 16, and heat from the heater 4 is directly transmitted to the processing tube 2 through the through hole, so that a significant temperature difference does not occur in the object 8 to be processed. This is because the significance of the soaking tube 16 is diminished.

  However, in the structure in which the uneven portions of the surface on the opposite side of the electrode 6 (7) side of the heat equalizing tube 16 are provided, a uniform continuous portion exists inside the heat equalizing tube 16 and passes through that portion. There is also an eddy current flowing through.

  Therefore, in this embodiment, as shown in FIG. 6, the SiC soaking tube 16 has a double structure of the inner tube 18 and the outer tube 19, the inner tube 18 is provided with pores 20, and the outer tube 19 is provided with pores 21. Is provided. The pore 20 penetrates the inner tube 18, and the pore 21 penetrates the outer tube 10. In this way, by providing the penetrating pores 20 and 21 in the inner tube 18 and the outer tube 19 respectively, there is no uniformly continuous portion, and the resistance values of the inner tube 18 and the outer tube 19 are reduced. Can be raised. Furthermore, since the path of the eddy current flowing through the inner pipe 18 is blocked by the pore 21 and may be bypassed to the outer pipe 19, contact resistance is utilized by fitting the inner and outer pipes without being integrally molded. Thus, the electrical contact between the inner and outer tubes is obstructed, and the bypass current is reduced.

  The pores 20 of the inner tube 18 and the pores 21 of the outer tube 19 are arranged so as not to communicate with each other to prevent a through-hole from being formed in the soaking tube 16, and the space on the electrode 6 (7) side and the heater The space on the 4 side is isolated so that heat from the heater 4 is not directly transmitted to the processing tube 2 so that a significant temperature difference does not occur in the object 8 to be processed.

  By adopting the double soaking tube 16 with the pores 20 and 21, eddy current can be reduced and RF power can be efficiently converted into plasma. As a result, energy can be used efficiently and plasma can be easily generated.

Next, the operation of this apparatus will be described.
When the processing chamber 1 is at atmospheric pressure, the elevator cap (see FIG. 9) lowers the seal cap 3 in order to load the processing object 8 into the boat 15, and the processing object transfer robot (wafer transfer machine 112, FIG. 9). , Refer to FIG. 10), after the required number of objects 8 to be processed are placed on the boat 15, the seal cap 3 is raised and inserted into the processing chamber 1.

  Electric power is supplied to the heater 4 to heat members in the processing chamber 1 such as the object 8 to a predetermined temperature. If the temperature of the heater is excessively lowered during the transfer of the object to be processed, it takes a considerable amount of time to stabilize the temperature within the processing chamber by raising the temperature to a predetermined value after the transfer of the object to be processed. Usually, the temperature is lowered to a temperature that does not hinder the conveyance of the object to be processed, and the conveyance is performed in a state where the temperature is maintained.

  At the same time, the gas inside the processing pipe 1 is exhausted by a pump 12 through an exhaust pipe 10 from an exhaust port not shown. When the object to be processed 8 reaches a predetermined temperature, a reactive gas is introduced into the processing chamber 1 from the gas introduction port 13, and the pressure in the processing chamber 1 is maintained at a constant value by the pressure adjustment valve 11.

  When the inside of the processing chamber 1 reaches a predetermined pressure, AC power output from the high-frequency power source 5 is supplied to the first electrode 6 via the matching unit 9, and the second electrode 7 is used as a counter electrode to generate plasma between the electrodes. Generate and process the object 8 to be processed.

  Next, with reference to FIG. 5 and FIG. 6, the outline of the substrate processing apparatus according to a preferred embodiment of the present invention will be described.

  A cassette stage 105 is provided on the front side of the inside of the housing 101 as a holder transfer member that transfers the cassette 100 as a substrate storage container to and from an external transfer device (not shown). Is provided with a cassette elevator 115 as lifting means, and a cassette transfer machine 114 as a conveying means is attached to the cassette elevator 115. A cassette shelf 109 as a means for placing the cassette 100 is provided on the rear side of the cassette elevator 115, and a spare cassette shelf 110 is also provided above the cassette stage 105. A clean unit 118 is provided above the spare cassette shelf 110 so that clean air is circulated inside the housing 101.

  A processing furnace 40 is provided above the rear portion of the casing 101, and a boat 15 as a substrate holding means for holding the wafers 8 as substrates in a horizontal posture in multiple stages is raised and lowered to the processing furnace 40 below the processing furnace 40. A boat elevator 121 as an elevating means is provided, and a seal cap 3 as a lid is attached to the tip of an elevating member 122 attached to the boat elevator 121 to support the boat 26 vertically. Between the boat elevator 121 and the cassette shelf 109, a transfer elevator 113 as an elevating means is provided, and a wafer transfer machine 112 as a transfer means is attached to the transfer elevator 113. A furnace opening shutter 116 as a shielding member that has an opening / closing mechanism and closes the lower surface of the processing furnace 40 is provided beside the boat elevator 121.

  The cassette 100 loaded with the wafer 8 is carried in an upward posture from the external transfer device (not shown) to the cassette stage 105, and is rotated by 90 ° on the cassette stage 105 so that the wafer 8 is in a horizontal posture. Further, the cassette 100 is transported from the cassette stage 105 to the cassette shelf 109 or the spare cassette shelf 110 by cooperation of the raising / lowering operation of the cassette elevator 115, the transverse operation, the advance / retreat operation of the cassette transfer machine 114, and the rotation operation.

  The cassette shelf 109 has a transfer shelf 123 in which the cassette 100 to be transferred by the wafer transfer device 112 is stored. The cassette 100 to which the wafer 8 is transferred is transferred by the cassette elevator 115 and the cassette transfer device 114. Transferred to the transfer shelf 123.

  When the cassette 100 is transferred to the transfer shelf 123, the wafer 8 is transferred from the transfer shelf 123 to the lowered boat 15 by the cooperation of the advance / retreat operation, rotation operation, and lifting / lowering operation of the transfer elevator 113 of the wafer transfer device 112. Is transferred.

  When a predetermined number of wafers 8 are transferred to the boat 15, the boat 15 is inserted into the processing furnace 40 by the boat elevator 121, and the processing furnace 40 is airtightly closed by the seal cap 3. The wafer 8 is heated and the processing gas is supplied into the processing furnace 40 in the hermetically closed processing furnace 40, and the wafer 8 is processed.

  When the processing on the wafer 8 is completed, the wafer 8 is transferred from the boat 15 to the cassette 100 of the transfer shelf 123 by the reverse procedure of the above-described operation, and the cassette 100 is transferred from the transfer shelf 123 by the cassette transfer device 114. It is transferred to the cassette stage 105 and carried out of the housing 101 by an external transfer device (not shown). The furnace port shutter 116 closes the lower surface of the processing furnace 40 when the boat 15 is in the lowered state, and prevents outside air from being caught in the processing furnace 24.

  The transport operation of the cassette transfer machine 114 and the like is controlled by the transport control means 124.

It is a schematic longitudinal cross-sectional view for demonstrating the processing furnace of the substrate processing apparatus of preferable Example of this invention. It is a schematic longitudinal cross-sectional view for demonstrating the processing furnace of the substrate processing apparatus of preferable Example of this invention. It is a schematic cross-sectional view for demonstrating the processing furnace of the substrate processing apparatus of preferable Example of this invention. It is a schematic perspective view for demonstrating the generation | occurrence | production form of an eddy current. It is a schematic longitudinal cross-sectional view for demonstrating the generation | occurrence | production form of an eddy current. It is a schematic longitudinal cross-sectional view for demonstrating the soaking | uniform-heating tube used with the processing furnace of the substrate processing apparatus of preferable Example of this invention. It is a partial expansion schematic side view of the A section of FIG. FIG. 8 is a schematic vertical sectional view taken along line BB in FIG. 7. It is a schematic perspective view for demonstrating the substrate processing apparatus of the preferable Example of this invention. It is a schematic longitudinal cross-sectional view for demonstrating the substrate processing apparatus of the preferable Example of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Processing chamber 2 ... Processing pipe 3 ... Seal cap 4 ... Heater 5 ... High frequency power supply 6, 6a-6h ... 1st electrode 7, 7a-7h ... 2nd electrode 8 ... To-be-processed object (silicon wafer)
DESCRIPTION OF SYMBOLS 9 ... Matching device 10 ... Exhaust piping 11 ... Pressure control valve 12 ... Pump 13 ... Gas introduction port 14 ... Gas supply nozzle 15 ... Boat 16 ... Soaking pipe 18 ... Soaking pipe inner pipe 19 ... Soaking pipe outer pipe 20 ... Soaking Pore of inner tube 21 ... Pore of soaking outer tube 25 ... Pore for gas supply 31 ... Current 32 ... Magnetic field 33 ... Eddy current 34 ... Synthetic eddy current 40 ... Processing furnace 100 ... Cassette 101 ... Housing 105 ... Cassette Stage 109 ... Cassette shelf 110 ... Preliminary cassette shelf 112 ... Wafer transfer machine 113 ... Transfer elevator 114 ... Cassette transfer machine 115 ... Cassette elevator 116 ... Furnace port shutter 118 ... Clean unit 121 ... Boat elevator 122 ... Lifting member 123 ... Transfer shelf 124 ... Conveyance control means

Claims (1)

A processing tube forming a space for accommodating the substrate;
A soaking tube arranged to cover the processing tube from the outside;
Heating means disposed around the soaking tube;
Arranged in a space between the processing tube and the soaking tube, and comprising at least a pair of electrodes to which high-frequency power is applied,
A substrate processing apparatus, wherein an uneven portion is provided on at least the surface of the soaking tube on the electrode side.

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