JP2005197523A - Substrate treatment equipment - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To effectively prevent high-frequency noise occurring from a plasma source in a treatment chamber from being transmitted to a heating means provided outside of the treatment chamber though this substrate treatment equipment is compact. <P>SOLUTION: The substrate treatment equipment is provided with a reaction tube 203 for forming the treatment chamber 201 inside, and treats a wafer 200 by utilizing plasma generated by the plasma source 250 in the treatment chamber 201. A conductive shield member 208 is formed between the treatment chamber 201 and a heater 207 provided outside of the treatment room 201, and a reaction tube 203 is covered with the shield member 208. By grounding E the shield member 208, the high-frequency noise occurring from the plasma source 250 in the treatment chamber 201 is suppressed. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a substrate processing apparatus that suppresses high-frequency noise generated from a plasma source in a processing chamber.

The substrate processing apparatus has a processing furnace, and a film forming process is performed on a substrate such as a wafer in the processing furnace. As a method for forming the film, a CVD method using plasma or an ALD method may be employed. Here, a film forming treatment method using the ALD method capable of lowering the film forming temperature as compared with the CVD method will be briefly described.
In the ALD method, under one film formation condition (temperature, time, etc.), two kinds (or more) of raw material gases used for film formation are alternately supplied onto the substrate one by one, and one atomic layer unit. In this method, the film is adsorbed by using a surface reaction to form a film.

Such an ALD apparatus has a discharge electrode as a plasma source installed in a reaction tube to generate plasma so that even a source gas activated at high temperature can be activated at low temperature by plasma. It has a structure.
A heater is disposed outside the reaction tube so as to cover the reaction tube. A heater thermocouple is provided in the heater, and a desired reaction temperature is obtained in the reaction tube by controlling the heater with a heating control system based on the detected temperature of the heater thermocouple.
The heater is provided with a power line for supplying power to the heater, a signal line for sending a heater thermocouple signal, and the like.

In such an ALD apparatus, high-frequency noise generated by the discharge electrode is superimposed on the power line or signal line while plasma is generated at the discharge electrode, and may cause a malfunction in the heating control system that controls the heater. is there.
Therefore, conventionally, as a countermeasure against high-frequency noise from the discharge electrodes, noise filters are respectively inserted in the power line and the signal line of the heater thermocouple.

As described above, conventionally, as a countermeasure against noise from the discharge electrode provided in the processing chamber, a noise filter has been attached to each of the power line and signal line constituting the heating means, but each noise filter is very large. Since the size of the processing chamber becomes a whole, it is difficult to secure a space for installing the noise filter.
An object of the present invention is to provide a substrate processing apparatus that can solve the above-described problems of the prior art and can effectively prevent high-frequency noise from being transmitted to a heating means while being compact.

  According to a first aspect of the present invention, there is provided a substrate processing apparatus for processing a substrate to be processed using plasma generated by a plasma source in a processing chamber. The substrate processing apparatus is characterized in that high-frequency noise generated from a plasma source in the processing chamber is suppressed by providing the shield and grounding the shield.

Since the high frequency noise generated from the plasma source is suppressed by the grounded shield, it is possible to effectively prevent the high frequency noise from being transmitted to the heating means.
A second invention is a substrate processing apparatus according to the first invention, wherein the shield is configured in a net shape. When the shield is configured in a net shape, the temperature stabilization time of the substrate to be processed can be shortened as compared with a configuration in which the shield is configured in a sheet shape.

  According to the present invention, it is possible to prevent high-frequency noise from being transmitted to the heating means, and therefore it is possible to effectively prevent malfunction due to high-frequency noise in the heating control system that controls the heating means.

Hereinafter, an embodiment of a substrate processing apparatus of the present invention used in one step of a semiconductor device manufacturing process will be described with reference to the drawings.
FIG. 1 is a schematic cross-sectional view of a vertical processing furnace 202 of the substrate processing apparatus of the present invention.
The processing chamber 201 is hermetically configured with a reaction tube 203 and a seal cap 219, and a buffer chamber 237 integrated with the reaction tube 203 is provided at a side portion in the processing chamber 201. The walls constituting the reaction tube 203 and the buffer chamber 237 are made of a dielectric such as quartz.

  The reaction tube 203 is provided with two gas supply tubes 232a and 232b for supplying a plurality of types, here two types of gases. The reaction gas is supplied from the first gas supply pipe 232a to the processing furnace 202 through the first mass flow controller 241a, the first valve 243a, and the nozzle 233, and further through the buffer chamber 237 formed in the processing furnace 202. Is done. The reaction gas is supplied from the second gas supply pipe 232b to the processing chamber 201 via the second mass flow controller 241b, the second valve 243b, the gas reservoir 247, and the third valve 243c, and further via the gas supply unit 249. Have been supplied.

  In the buffer chamber 237 described above, a pair of rod-shaped discharge electrodes 270 for generating plasma are provided protected by an electrode protection tube 275 (in the figure, one of the pair of discharge electrodes and the electrode protection tube). Only the reaction gas introduced from the first gas supply pipe 232a through the nozzle 233 is converted into plasma in the buffer chamber 237, and the substrate to be processed is formed from the gas supply hole 248a provided in the buffer chamber 237. As a result, active particles are blown out toward the wafer 200. The pair of discharge electrodes 270 and the electrode protection tube 275 constitute a plasma source 250 in the processing chamber 201.

  A pair of discharge electrodes 270 for forming plasma is drawn out from the reaction tube 203 together with the electrode protection tube 275, and one of the discharge electrodes 270 shown in the figure is connected to a high frequency power source 273 via a matching unit 272, The other discharge electrode not grounded is grounded, so that high-frequency power output from the high-frequency power source 273 can be supplied to the pair of discharge electrodes 270 via the matching unit 272.

  On the other hand, the gas supply unit 249 described above serves as a supply unit that shares the gas supply species with the buffer chamber 237 when alternately supplying a plurality of types of gases one by one to the wafer 200 in film formation by the ALD method. Similarly to the buffer chamber 237, the gas supply unit 249 also has a second gas supply hole 248c for supplying gas to a position adjacent to the wafer 200, and is connected to the second gas supply pipe 232b at the lower part.

  The second gas stored in the gas reservoir 247 is supplied to the surface of the wafer 200 in the processing chamber 201 all at once, and the supply of the second gas causes the first gas and the second gas on the wafer 200 to be changed. A film is formed on the wafer 200 by surface reaction.

  The reaction tube 203 is connected to a vacuum pump 246 through a fourth valve 243d by a gas exhaust tube 231 for exhausting gas, and is evacuated.

  The processing furnace 202 includes a heater 207 that is a heating unit. The heater 207 has a cylindrical shape and has an upper portion closed by a ceiling plate 207a. A heating resistor (not shown) constituting the heater 207 is provided only in the cylindrical portion excluding the ceiling plate 207a of the cylindrical heater 207. A metal cooling pipe 206 is wound around the outer surface of the cylindrical portion, and water is allowed to flow through the cooling pipe 206 to cool the corresponding portion of the heating resistor. In addition, an outside air introduction path 207c is formed in the ceiling plate 207a to communicate outside air and the cylindrical inner space 210. A cooling unit 205 for rapidly cooling the temperature of the heater 207 is connected to the outside air inlet of the outside air introduction path 207c.

  The inside of the processing chamber 201 is structured to be heated by a heater 207 provided outside the reaction tube 203. A terminal of the power line 225 a that supplies power to the heater 207 is connected to the power source 224 via the thyristor 223. The thyristor 223 is provided with a thyristor controller 222 for phase control of the conduction angle, and receives an electric signal (detected temperature signal) from the signal line 221a of the heater thermocouple 221 provided in the heater 207. It is configured to perform predetermined temperature control. The thyristor 223, the thyristor controller 222, and the heater thermocouple 221 constitute a heating control system 230 that supplies power to the heater 207.

  A boat 217 for mounting a plurality of wafers 200 in multiple stages at the same interval is provided at the center of the reaction tube 203. The boat 217 is erected on a seal cap 219 that hermetically closes the lower end opening 204 of the reaction tube 203 via a rotating shaft 211 and a boat table 218 that are sealed with a magnetic seal 212. The boat 217 can enter and exit the reaction tube 203 by a boat elevator (not shown). Further, a boat rotation mechanism 267 for rotating the boat 217 is provided in order to improve the uniformity of processing, and the boat held on the boat table 218 via the rotation shaft 211 by rotating the boat rotation mechanism 267. 217 is rotated.

Next, a film formation example by the ALD method will be described using the processing furnace 202 of the substrate processing apparatus described above. Here, a SiN film is formed using DCS and NH ₃ gas.

  First, the seal cap 219 on which the boat 217 for loading the wafers 200 is lowered by an elevator mechanism (not shown). After placing the wafer 200 on the boat 217, the seal cap 219 is raised and inserted into the processing chamber 201. The power source 224 is turned on to the heater 207, and the reaction tube 203, the boat 217 inside, the wafer 200, and the like are heated to a predetermined temperature. At the same time, the inside of the processing chamber 201 is exhausted from the exhaust pipe 231 by the pump 246. The temperature of the heater 207 is measured by the heater thermocouple 221. Upon receiving the detected temperature detection signal, the thyristor control unit 222 controls the phase of the conduction angle of the thyristor 223 so that the temperature reaches a predetermined temperature. Adjust the power supply. When the wafer 200 reaches a predetermined temperature, the pressure in the processing chamber 201 is held at a predetermined value by a pressure adjusting mechanism (not shown). Then, when the pressure inside the processing chamber 201 reaches a predetermined pressure, the following three steps are sequentially executed.

In step 1, NH ₃ gas that requires plasma excitation is supplied. The first valve 243a provided in the first gas supply pipe 232a and the fourth valve 243d provided in the gas exhaust pipe 231 are both opened, and the flow rate is supplied from the first gas supply pipe 232a by the first mass flow controller 241a. The adjusted NH ₃ gas is jetted from the second gas supply hole (not shown) of the nozzle 233 to the buffer chamber 237. High frequency power is applied between the pair of discharge electrodes 270 from the high frequency power supply 273 via the matching unit 272 to discharge between the pair of discharge electrodes 270 to excite NH ₃ and supply it to the processing chamber 201 as active species. While exhausting from the gas exhaust pipe 231. NH _{3 that} is excited by the plasma and becomes active species reacts with the underlying film on the wafer 200.

In step 2, DCS gas that does not require plasma excitation is stored. When NH ₃ is supplied as an active species in Step 1, the second valve 243b on the upstream side of the second gas supply pipe 232b is opened, the third valve 243c on the downstream side is closed, and DCS is also flowed. To. As a result, DCS is stored in the gas reservoir 247 provided between the second and third valves 243b and 243c. Even after the first valve 243a of the first gas supply pipe 232a is closed and the supply of NH ₃ is stopped, the supply to the gas reservoir 247 is continued. When a predetermined pressure and a predetermined amount of DCS accumulate in the gas reservoir 247, the second valve 243b on the upstream side is also closed, and the DCS is confined in the gas reservoir 247. Further, the fourth valve 243 d of the gas exhaust pipe 231 is kept open, and the processing furnace 202 is evacuated to 20 Pa or less by the vacuum pump 246, and residual NH ₃ is removed from the processing chamber 201.

In step 3, DCS gas is supplied to perform film formation. When the exhaust of the processing chamber 201 is finished, the fourth valve 243d of the gas exhaust pipe 231 is closed to stop the exhaust. The third valve 243c on the downstream side of the second gas supply pipe 232b is opened, and the DCS stored in the gas reservoir 247 is supplied to the processing chamber 201 at once. At this time, since the fourth valve 243d of the gas exhaust pipe 231 is closed, the pressure in the processing furnace 202 rapidly increases. Since the gas adsorption amount is proportional to the gas pressure and the gas exposure time, a desired amount of gas can be instantaneously adsorbed by a rapid pressure increase.
By supplying DCS, NH ₃ and DCS on the base film react with each other to form a SiN film on the wafer 200. After the film formation, the third valve 243c is closed, the fourth valve 243d is opened, and the processing furnace 202 is evacuated to remove the gas after contributing to the film formation of the remaining DCS. Also, the second valve 243b is opened to start supplying DCS to the gas reservoir 247.

  Steps 1 to 3 are defined as one cycle, and this cycle is repeated a plurality of times to form a SiN film having a predetermined thickness on the wafer.

  By the way, as described above, in the processing furnace 202, the heater 207 for heating the wafer 200 has a power line 225a for supplying power to the heater 207, a signal line for sending signals from the heater thermocouple 221 and the heater thermocouple 221. 221a, a cooling pipe 206 wound around the outer periphery of the heater 207 to cool the heater 207, a cooling unit 205 for rapidly lowering the temperature of the heater 207, and the like are provided.

  As described above, the cooling pipe 206 is made of metal, and the cooling pipe 206 is wound around the entire outer surface of the heater 207. The cooling unit 205 includes, for example, a radiator, a water pump, a thermostat, a cooling fan, and the like. The circulation amount of the cooling liquid fed to the radiator by the water pump and the cooling fan for cooling the radiator are controlled by a thermostat, and the outside air is cooled to a predetermined temperature by the radiator. By supplying this outside air to the cylindrical inner space 210 of the heater 207, the temperature of the heater 207 is rapidly lowered.

In an ALD apparatus in which such a heater 207 is provided with a power line 225 a, a heater thermocouple 221, a signal line 221 a, a cooling pipe 206, and a cooling unit 205, discharge is performed while plasma is generated by a pair of discharge electrodes 270. A part of the high-frequency power generated by the electrode 270 is superimposed on the heater 207, and the high-frequency power is transmitted to the thyristor 223 and the thyristor control unit 222, which affects the accuracy of the temperature control. Further, the heater thermocouple 221 malfunctions due to high frequency noise, and proper temperature control cannot be performed.
In addition, the cooling pipe 206 provided on the outer periphery of the heater 207 picks up high frequency components generated from the plasma source 250 in the reaction tube 203, and the cooling pipe 206 serves as an antenna, and high frequency noise adversely affects the heater thermocouple 221. The heater thermocouple 221 may malfunction. Furthermore, noise generated from a water pump, a cooling fan, or the like that constitutes the cooling unit 205 provided in the heater 207 may cause a malfunction in the thermocouple 221 or the heating control system 230.

  As a conventional countermeasure against high frequency noise from the discharge electrode 270, when noise filters are inserted in the power line 225a and the signal line 221a of the heater thermocouple 221, respectively, the power line 225a and the heater thermoelectric power are included in the noise described above. Noise on the signal line 221a of the pair 221 can be temporarily removed by a noise filter. However, it is difficult to remove noise on the cooling pipe 206 and noise from the cooling unit 205. Moreover, since the cooling pipe 206 and the cooling unit 205 are provided in the heater 207, the influence on the heater 207 and the heater thermocouple 221 is large.

  Therefore, in the embodiment, a shield member 208 for electric field shielding is provided between the reaction tube 203 and the heater 207, and the reaction tube 203 having the discharge electrode 270 serving as a noise source is covered with the shield member 208. Yes. The shield member 208 is formed of a conductive member in a sheet shape and is connected to the ground E. The conductive member is made of, for example, SUS.

By covering the outer periphery of the reaction tube 203 with the shield member 208 in this way, high frequency noise generated from the plasma source 250 in the processing chamber can be suppressed. Therefore, in the ALD apparatus, even when the plasma is generated by the pair of discharge electrodes 270, the high-frequency noise generated by the discharge electrodes 270 is prevented from being superimposed on the heater 207, and the heating for controlling the heater 207 is controlled. It is possible to effectively prevent malfunction due to high frequency noise of the control system. In addition, the heater thermocouple 221 can be appropriately controlled without malfunction due to high frequency noise.
In addition, the cooling pipe 206 provided on the outer periphery of the heater 207 does not pick up high-frequency components generated from the plasma source 250 in the reaction tube 203, and high-frequency noise adversely affects the heater thermocouple 221 in the heater 207. Therefore, there is no possibility that the thermocouple 221 malfunctions.
Furthermore, since noise generated from a water pump, a cooling fan, or the like constituting the cooling unit 205 connected to the heater 207 is also shielded by the shield member 208, a malfunction occurs in the heater thermocouple 221 or the heating control system 230. There is no fear.

Moreover, since the shield member 208 made of metal can be formed of a thin plate, an extra space is required between the reaction tube 203 and the heater 207 provided outside the reaction tube 203 unlike a large noise filter. Can be intervened. Therefore, the processing furnace can be made compact.
Further, the outer periphery of the reaction tube 203 is covered with the shield member 208 and grounded, so that electromagnetic radiation to the outside can also be prevented.

In the embodiment, the shield member 208 is configured in a sheet shape, but may be configured in a net shape. If the shield member is configured in a net shape, the temperature stabilization time of the substrate to be processed can be shortened as compared with the sheet member. That is, since there is a shield member 208 between the processing chamber 201 and the heater 207, the shield member 208 serves as a resistance for heat transfer from the heater 207 when the temperature of the wafer 200 inserted into the processing chamber 203 is heated and increased. In some cases, extra time is required to stabilize the temperature of the wafer 200. However, if the shield member 208 is a net-like shield member, the resistance to heat transfer is reduced, so that the temperature stabilization time of the substrate to be processed can be shortened compared to the case of a sheet.
Further, according to the embodiment, the case where the present invention is applied to an ALD apparatus has been described. However, the present invention can be applied to other plasma processing apparatuses as long as the plasma source is provided in the processing chamber. . As another plasma processing apparatus, for example, there is a plasma CVD apparatus.

It is sectional drawing of the processing furnace which comprises the substrate processing apparatus by embodiment.

Explanation of symbols

210 processing chamber 250 plasma source 200 substrate to be processed 207 heater (heating means)
208 Shield member (conductive shield)
221 Heater thermocouple E Ground

Claims (1)

In a substrate processing apparatus for processing a substrate to be processed using plasma generated by a plasma source in a processing chamber,
A conductive shield is provided between the processing chamber and a heating means provided outside the processing chamber,
A substrate processing apparatus characterized in that high-frequency noise generated from a plasma source in the processing chamber is suppressed by grounding the shield.

Images