Plasma processing apparatus and method of manufacturing semiconductor device

The present invention increases uniformity of plasma processing in a surface to be processed of an object to be processed or increases uniformity of plasma processing between objects to be processed. There is provided a plasma processing apparatus including: a processing container; a gas supply system; an exhaust system; a plasma generating unit; a gas flow path installed between an outer wall of the processing container and the plasma generating unit, the gas flow path guiding a temperature controlling gas to flow along the outer wall of the processing container; a plurality of gas introduction holes disposed along a circumferential direction of the processing container and configured to introduce the temperature controlling gas into the gas flow path; and a gas exhaustion hole configured to exhaust the temperature controlling gas passed through the gas flow path.

CROSS-REFERENCE TO RELATED PATENT APPLICATION

This U.S. non-provisional patent application claims priority under 35 U.S.C. § 119 of International Application No. PCT/JP2014/058865, filed on Mar. 27, 2014, in the WIPO, the whole contents of which are hereby incorporated by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a plasma processing apparatus and a method of manufacturing a semiconductor device.

2. Description of the Related Art

In the course of manufacturing a semiconductor device, a substrate processing apparatus configured to perform plasma processing on an object to be processed (for example, a wafer) is used in some cases. In a processing container of the substrate processing apparatus, plasma of a processing gas is generated, and plasma processing is performed on the object to be processed. A batch process in which a plurality of objects to be processed are transferred in the substrate processing apparatus and plasma processing is sequentially performed on the transferred objects to be processed is performed.

However, uniformity of plasma processing is low in a surface to be processed of an object to be processed in some cases. Also, uniformity of plasma processing between objects to be processed is low in some cases. Therefore, the present invention provides a plasma processing apparatus and a method of manufacturing a semiconductor device through which uniformity of plasma processing in the surface to be processed of the object to be processed can increase or uniformity of plasma processing between objects to be processed can increase.

SUMMARY OF THE INVENTION

According to an aspect of the present invention, there is provided a plasma processing apparatus including: a processing container configured to accommodate an object to be processed; a gas supply system configured to supply a processing gas into the processing container; an exhaust system configured to exhaust an inside atmosphere of the processing container; a plasma generating unit installed outside the processing container and configured to generate a plasma of the processing gas supplied into the processing container; a gas flow path installed between an outer wall of the processing container and the plasma generating unit, the gas flow path guiding a temperature controlling gas to flow along the outer wall of the processing container; a plurality of gas introduction holes disposed along a circumferential direction of the processing container and configured to introduce the temperature controlling gas into the gas flow path; and a gas exhaustion hole configured to exhaust the temperature controlling gas passed through the gas flow path.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

<Knowledge Obtained by the Inventors>

First, knowledge obtained by the inventors will be described. In the course of manufacturing a semiconductor device, a semiconductor manufacturing apparatus (substrate processing apparatus) configured to perform plasma processing on an object to be processed is used. Examples of the semiconductor manufacturing apparatus include a plasma processing apparatus. The plasma processing apparatus generates plasma of a processing gas in a processing container and performs plasma processing on an object to be processed. A batch process in which a plurality of objects to be processed are transferred in the plasma processing apparatus and plasma processing is sequentially performed on the transferred objects to be processed is performed.

The term “plasma processing” used herein refers to ashing of a resist film formed on an object to be processed, etching of a metal film or a semiconductor film formed on the object to be processed, or oxidation, nitridation or ashing of a metal film or a semiconductor film formed on the object to be processed.

The inventors have found that a rate of plasma processing or a degree of plasma processing on the object to be processed in the plasma processing apparatus depends on a temperature of the processing container. The term “a rate of plasma processing” used herein refers to a rate of, for example, ashing, etching, oxidation or nitridation. Also, the term “a degree of plasma processing” refers to a degree (such as a concentration or a depth) of, for example, oxidation or nitridation.

When a temperature of the processing container or a temperature of a coil installed to surround the processing container is nonuniform in a circumferential direction, a temperature distribution of the object to be processed itself is non-uniformized in a planar direction in some cases. Also, a plasma density of a plasma generating region is non-uniformized in the planar direction of the object to be processed in some cases. A rate of plasma processing near a region at which a temperature of the processing container is low is lower than a rate of plasma processing near a region at which a temperature of the processing container is high. Also, a degree of plasma processing near a region at which a temperature of the processing container is low is lower than a degree of plasma processing near a region at which a temperature of the processing container is high. Therefore, uniformity of plasma processing in a surface to be processed of the objects to be processed is likely to decrease.

Also, there is a concern about an increasing temperature of the processing container over time when plasma processing is performed. For example, when plasma processing is performed on one object to be processed, a temperature of the processing container when the processing ends is higher than a temperature of the processing container when the processing starts. Also, when plasma processing is consecutively performed on the plurality of objects to be processed, a temperature of the processing container when processing is performed on the plurality of objects to be processed is higher than a temperature of the processing container when processing is performed on a first object to be processed. In this case, a temperature of the object to be processed itself may be changed over time or a plasma density of the plasma generating region may be changed over time. Accordingly, a rate of plasma processing or a degree of plasma processing is changed over time during processing or for each processing. Therefore, uniformity of plasma processing between the objects to be processed is likely to decrease.

Therefore, the present inventors have conducted research on methods of addressing the above problems and have found the following knowledge.

A gas flow path of a temperature controlling gas is installed along an outer wall of the processing container between the processing container and a plasma generating unit. In the gas flow path, a gas introduction hole and a gas exhaustion hole are installed. The gas introduction holes are disposed in a circumferential direction of the processing container at equal intervals. The temperature controlling gas is uniformly introduced in the circumferential direction of the processing container through the gas introduction hole. The processing container is uniformly cooled in the circumferential direction due to the temperature controlling gas. The temperature of the processing container is uniformized in the circumferential direction. Therefore, uniformity of plasma processing within planes of the object to be processed increases.

Also, a gas exhaustion pipe is connected to the gas exhaustion hole. An adjusting valve is installed at the gas exhaustion pipe. A flow rate of the temperature controlling gas is controlled by adjusting a degree of opening of the adjusting valve. The temperature of the processing container remains in a predetermined temperature. Therefore, it is possible to suppress a rate of plasma processing or a degree of plasma processing from being changed over time during processing or for each processing. Accordingly, uniformity of plasma processing between the objects to be processed increases.

As described above, it is possible to increase uniformity of plasma processing within planes of the object to be processed or uniformity of plasma processing between the objects to be processed. The following embodiments are based on the above knowledge.

(1) Structure of Plasma Processing Apparatus

FIG. 1is a cross sectional view schematically illustrating a plasma processing apparatus according to an embodiment of the present invention. The plasma processing apparatus10includes a processing container120configured to accommodate a wafer20serving as an object to be processed; a gas supply system configured to supply a processing gas into the processing container120; an exhaust system configured to exhaust an inside of the processing container120; a plasma generating unit installed outside the processing container120and configured to excite the processing gas supplied into the processing container120; a gas flow path140installed between the processing container120and the plasma generating unit such that a temperature controlling gas flows along the outer wall of the processing container120; a gas introduction hole152ainstalled in a circumferential direction of the processing container120at equal intervals and configured to introduce the temperature controlling gas into the gas flow path140; and a gas exhaustion hole185configured to exhaust the temperature controlling gas passed through the gas flow path140. Hereinafter, details thereof will be described.

The term “plasma processing” in the present embodiment refers to, for example, ashing of a resist film formed on a processing surface of the object to be processed. Specifically, the term “plasma processing” refers to, for example, ashing of a resist film applied onto a wafer or performing a descum process on a semiconductor device in which a bump electrode is formed. Also, the descum process refers to a process of removing a resist residue (called a scum) generated when the resist film is patterned. Therefore, in the present embodiment, “the object to be processed” includes a wafer20(called a whole wafer) before dicing (before processing), a semiconductor device or a semiconductor package after dicing (after processing) and the like. In the present embodiment, the object to be processed will be described as the wafer20before processing.

The plasma processing apparatus10includes the processing container120that contains a reaction tube131and a wafer accommodating unit190. The plasma processing apparatus10may include a loadlock seal (not illustrated) configured to accommodate at least one or a plurality of wafers20on which one batch process is performed, and a transfer chamber (not illustrated) having a transfer unit configured to sequentially transfer the wafer20into the processing container120. In the present embodiment, the plasma processing apparatus10is a single wafer processing apparatus. In the processing container120, the wafer20is transferred one by one, and plasma processing is sequentially performed on the wafer20.

The reaction tube131has, for example, a cylindrical shape. The reaction tube131is made of, for example, ceramics or quartz glass of high purity. An upper end and a lower end of the reaction tube131are opened. The reaction tube131is installed on a base plate148serving as a stand. A central axis of the reaction tube131is installed in a normal line direction of the base plate148.

A top plate154having a disk shape is installed at an upper opening of the reaction tube131. The top plate154seals the upper opening of the reaction tube131. The top plate154comes in contact with the reaction tube131through an O ring (not illustrated). A plasma generating region130is formed in the reaction tube131.

A gas introducing port133is installed at the center of the top plate154. The processing gas or a purge gas is supplied into the processing container120through the gas introducing port133.

The gas supply system is connected to the gas introducing port133. The gas supply system is configured to supply the processing gas or the purge gas into the processing container120. The gas supply system includes a processing gas supply system configured to supply the processing gas into the processing container120and a purge gas supply system configured to supply the purge gas into the processing container120. Also, the purge gas supply system serves as a carrier gas supply system configured to facilitate supply of the processing gas into the processing container120.

A downstream end of a pipe52cthrough which the processing gas flows is connected to the gas introducing port133. A valve52ais installed at the pipe52c. A mass flow controller52bis installed upstream from the valve52aof the pipe52c. The mass flow controller52bis configured to adjust a flow rate of the processing gas. A processing gas bombe (not illustrated) is connected upstream from the mass flow controller52bof the pipe52c. The processing gas supply system mainly includes the pipe52c, the valve52aand the mass flow controller52b. Also, the processing gas bombe may be included in the processing gas supply system.

A type of the processing gas is appropriately selected according to content of plasma processing. As the processing gas, for example, at least any of oxygen (O2) gas, hydrogen (H2) gas, nitrogen (N2) gas, argon (Ar) gas, helium (He) gas, tetrafluoromethane (CF4) gas and trifluoromethane (CHF3) gas or a combination thereof is used.

A downstream end of a pipe51cthrough which the purge gas flows is connected downstream from the valve52aof the pipe52c. A valve51ais installed at the pipe51c. A mass flow controller51bis installed upstream from the valve51aof the pipe51c. The mass flow controller51badjusts a flow rate of the purge gas. A purge gas bombe (not illustrated) is connected upstream from the mass flow controller51bof the pipe51c. The purge gas supply system mainly includes the pipe51c, the valve51aand the mass flow controller51b. Also, the purge gas bombe may be included in the purge gas supply system. As the purge gas, for example, N2gas or an inert gas such as a rare gas is used.

A dispersion plate160configured to rectify a gas supplied through the gas introducing port133is installed at an upper side in the processing container120. The dispersion plate160is made of, for example, quartz. A planar shape of the dispersion plate160is a shape according to an inner diameter of the reaction tube131and is substantially circular. The dispersion plate160is installed to be separated a predetermined interval from an inner wall of the processing container120, and is horizontally held. The dispersion plate160is formed as a plate having no hole. Therefore, the gas supplied through the gas introducing port133collides with the dispersion plate160, and flows from the upper side to a lower side in the processing container120along the inner wall of the processing container120.

A resonant coil132is installed outside the processing container120. The resonant coil132generates plasma of the processing gas supplied into the processing container120. The resonant coil132is wound along, for example, an outer circumference of the reaction tube131. A high frequency power source144is connected to the resonant coil132through an RF sensor168. The high frequency power source144applies high frequency power to the resonant coil132. Therefore, the processing gas becomes a plasma state in the plasma generating region130. A frequency matching unit146is connected to the resonant coil132through the RF sensor168. The RF sensor168is configured to monitor a traveling wave, a reflected wave or the like of high frequency power. A high frequency power value monitored by the RF sensor168is fed-back to the frequency matching unit146. The frequency matching unit146is configured to control an oscillation frequency such that the reflected wave of high frequency power is minimized.

The plasma generating unit mainly includes the resonant coil132. Also, the RF sensor168, the high frequency power source144and the frequency matching unit146may be included in the plasma generating unit. In this manner, the plasma processing apparatus10is an apparatus configured to perform plasma processing on the object to be processed by, for example, inductive coupling plasma (ICP).

Here, a winding diameter, a winding pitch, the number of windings and the like of the resonant coil132are set to resonate in a constant wavelength mode. The resonant coil132is configured to form a standing wave of a predetermined wavelength. That is, a length of the resonant coil132is set to a length corresponding to an integer multiple (1×, 2×, . . . ) of one wavelength, ½ wavelengths or ¼ wavelengths at a predetermined frequency of high frequency power supplied from the high frequency power source144. One wavelength has a length of, for example, about 22 m at 13.56 MHz, about 11 m at 27.12 MHz, and about 5.5 m at 54.24 MHz. The number of windings of the resonant coil132is, for example, 10. The resonant coil132has a winding diameter of, for example, 300 mm or more and 400 mm or less, and preferably 360 mm or more and 370 mm or less.

The resonant coil132is made of an insulating material, has a planar shape, and is supported with a plurality of supporting members (not illustrated) that are vertically provided on an upper end surface of the base plate148. Also, both ends of the resonant coil132are electrically grounded. At least one end of the resonant coil132is grounded through a movable tap162. Therefore, when the plasma processing apparatus10is initially installed or processing conditions are changed, it is possible to finely adjust the length of the resonant coil132. The other end of the resonant coil132is grounded through a fixed ground164. Also, between the both grounded ends of the resonant coil132, a power supply unit is configured by a movable tap166. Therefore, it is configured to such that, when the plasma processing apparatus10is initially installed or processing conditions are changed, an impedance of the resonant coil132can be finely adjusted. That is, the resonant coil132includes an electrically grounded ground portion at both ends, and includes the power supply unit configured to receive power from the high frequency power source144between the ground portions. A ground portion of at least one end is configured as a variable ground portion whose position is adjustable. Also, the power supply unit is configured as a variable power supply unit whose position is adjustable. When the resonant coil132includes the variable ground portion and the variable power supply unit, it is possible to easily adjust a resonant frequency and a load impedance of the plasma generating unit.

A shield unit152is installed to surround an outside of the resonant coil132serving as the plasma generating unit. The shield unit152has conductivity. The shield unit152shields an electromagnetic wave from leaking to the outside of the resonant coil132. A capacity component necessary for resonance is formed between the resonant coil132and the shield unit152. The shield unit152is made of a conductive material, for example, an aluminum alloy, copper or a copper alloy. The shield unit152has a cylindrical shape and is formed of a metal plate that is bent and processed in a cylindrical shape.

Here, when a capacitance capacity between the resonant coil132and the shield unit152is set to Cs, and a capacitance capacity between the resonant coil132and the reaction tube131is set to Cp, Cs>>Cp is established. The shield unit152is configured to satisfy the above condition. A diameter of the shield unit152is set based on an inner diameter of the reaction tube131and a winding diameter of the resonant coil132.

A height of the shield unit152is set to be higher than a height of a range at which the resonant coil132is disposed.

A lower end of the shield unit152preferably comes in contact with the base plate148to be described below. For example, when the lower end of the shield unit152is separated from the base plate148, an interval between the shield unit152and the base plate148is preferably smaller than a diameter of the gas introduction hole152aof the temperature controlling gas to be described below.

In the present embodiment, the shield unit152forms a part of the gas flow path140of the temperature controlling gas. Details thereof will be described below.

Below (at an exhaust system side) the reaction tube131, the wafer accommodating unit190is installed. The wafer accommodating unit190accommodates the wafer20. A lower opening of the reaction tube131is hermitically connected to the wafer accommodating unit190. A processing chamber145configured to process the wafer20is formed in the wafer accommodating unit190. The processing chamber145communicates with the above-described plasma generating region130. A lower opening of the wafer accommodating unit190is sealed by a bottom plate169having a bowl shape. Central axes of the wafer accommodating unit190, the reaction tube131and the bottom plate169each are vertically disposed.

A susceptor159is installed in the processing chamber145. The susceptor159includes a susceptor table111. The susceptor table111supports the wafer20. Below the susceptor table111, a plurality of supports161are installed. The plurality of supports161support the susceptor table111from below. A heater163is installed in the susceptor159. The heater163heats the wafer20supported on the susceptor159.

Below the susceptor table111, a lifting substrate171is installed. A guide shaft167is installed to communicate with the lifting substrate171. The guide shaft167guides lifting of the lifting substrate171. A plurality of lift pins113are installed on the lifting substrate171in a vertical direction. The lift pin113penetrates an outer circumference portion of the susceptor table111in a vertical direction. A substrate holding part114is installed at an upper end of the lift pin113. The substrate holding part114extends in a center direction of the susceptor table111and holds an outer circumference of the wafer20. The lifting substrate171is connected to an upper end of a lifting shaft173. The lifting shaft173penetrates through the bottom plate169and is connected to a lifting drive unit (not illustrated). The lifting drive unit lifts the lifting shaft173. Therefore, the substrate holding part114is lifted through the lifting substrate171and the lift pin113. Also, the wafer20can be moved onto the susceptor table111from the substrate holding part114or the wafer20can be moved to the substrate holding part114from the susceptor table111.

Below the susceptor table111, a baffle ring158is installed. The baffle ring158has, for example, a cylindrical shape. A space below the susceptor table111communicates with the processing chamber145. On the bottom plate169, an exhaust plate165is horizontally supported through the guide shaft167. An exhaust communicate hole175is installed in the exhaust plate165. A space formed above the exhaust plate165and a space formed below the exhaust plate165communicate through the exhaust communicate hole175.

A gas exhaustion pipe180is connected to the center of the bottom plate169. In the gas exhaustion pipe180, in order from an upstream end, a pressure sensor (not illustrated), an auto pressure controller (APC) valve181and an exhaust device179are installed. The exhaust device179is configured to exhaust the inside of the processing container120. When the exhaust device179exhausts the inside of the processing container120, a degree of opening of the APC valve181is adjusted based on pressure information from the pressure sensor. Therefore, a pressure in the processing container120is adjusted to a predetermined pressure. The exhaust system mainly includes the gas exhaustion pipe180and the APC valve181. Also, the exhaust device179may be included in the exhaust system.

Also, the reaction tube131and the wafer accommodating unit190need not be clearly separated. That is, these may be integrally formed. In this case, at least a part or all of the plasma generating region130and the processing chamber145may overlap.

A controller170serving as a control unit is connected to the mass flow controllers51band52b, the valves51aand52a, the high frequency power source144, the frequency matching unit146, the RF sensor168, the heater163, the lifting drive unit, the pressure sensor, the APC valve181, the exhaust device179and the like. The controller170is configured to control operations thereof. A display172serving as a display unit is connected to the controller170. The display172displays data, for example, a monitoring result of a reflected wave by the RF sensor168.

(2) Gas Flow Path of Temperature Controlling Gas

Hereinafter, a detailed configuration of the gas flow path140of the temperature controlling gas will be described with reference toFIGS. 1, 2aand2b.FIG. 2ais a cross sectional view taken along the line A-A′ ofFIG. 1as seen from an arrow direction.FIG. 2bis a development view of a shield unit. A solid arrow inFIGS. 1, 2aand2bindicates a flow of the temperature controlling gas.

In the present embodiment, in order to stabilize a temperature of the processing container120, the temperature controlling gas flows along the outer wall of the processing container120. The gas flow path140is installed between the processing container120and the resonant coil132serving as the plasma generating unit, and through which the temperature controlling gas flows along the outer wall of the processing container120. The temperature of the processing container120is stabilized due to so-called forced convection rather than natural convection.

The temperature controlling gas may be, for example, an atmosphere. The temperature controlling gas may be N2gas or an inert gas such as a rare gas.

As illustrated inFIG. 1, the gas introduction hole (air intake hole)152ais installed at the shield unit152. The gas introduction hole152ais configured to introduce the temperature controlling gas into the gas flow path140. The gas introduction hole152ais installed at a lower end side of the shield unit152. The gas introduction hole152ais positioned vertically below the resonant coil132. The gas introduction hole152ais installed below the movable tap166, that is, at an end further below a lower end portion of the resonant coil132. The temperature controlling gas is introduced from vertically below the resonant coil132. In other words, the temperature controlling gas is introduced from vertically below the plasma generating region130.

The number of gas introduction holes152a, a shape thereof, or a disposition thereof is set according to a required flow rate of the temperature controlling gas. Also, these are set according to an exhaust capacity of an exhaust device188to be described below.

As illustrated inFIG. 2a, a plurality of gas introduction holes152aare installed. The plurality of gas introduction holes152aare disposed in the circumferential direction of the processing container120within the gas flow path140at equal intervals. The term “the circumferential direction of the processing container120” refers to the circumferential direction of the processing container120in a birds-eye view of the plasma processing apparatus10. Each of the plurality of gas introduction holes152aintroduces the temperature controlling gas in a center direction of the reaction tube131. The temperature controlling gas is introduced through the plurality of gas introduction holes152a, and collides with the outer wall of the processing container120at a uniform flow rate and a uniform flow velocity. Therefore, the processing container120is easily uniformly cooled in the circumferential direction due to the temperature controlling gas.

As described above, the shield unit152is installed to surround an outside of the resonant coil132serving as the plasma generating unit. The plurality of gas introduction holes152aare installed in the shield unit152. At least a part of the gas flow path140is installed between the processing container120and the shield unit152.

As illustrated inFIG. 2b, the gas introduction hole152ahas a cross-sectional shape, for example, a circular shape. The number of gas introduction holes152a, a diameter thereof, or a disposition thereof is designed according to a required exhaust amount of the exhaust device188. For example, when a required flow rate of the temperature controlling gas is about 3 m3/min, a flow velocity of the temperature controlling gas may be about 1 m/sec to 3 m/sec. In this case, for example, a diameter of the gas introduction hole152ais 20 mm or more and 40 mm or less. The number of gas introduction holes152ais, for example, 10 or more and 100 or less and preferably 15 or more and 50 or less. An interval Wa between the plurality of gas introduction holes152ais, for example, 10 mm or more and 40 mm or less. A height Ha from the lower end of the shield unit152to the center of the gas introduction hole152ais, for example, about 1/10 of a height Hs of the shield unit152, and is, for example, 20 mm or more and 50 mm or less. Also, since the shield unit152comes in contact with the base plate148, the height Ha from the lower end of the shield unit152to the center of the gas introduction hole152ais, for example, the same as a height from the base plate148to the center of the gas introduction hole152a.

In the shield unit152, an opening162afor the movable tap162and an opening166afor the movable tap166are installed. The fixed ground164is withdrawn from the opening166afor the movable tap166. The opening162ais installed in a movable range of the movable tap162. The opening166ais installed in a movable range of the movable tap166.

A gas guide (an air flow guide)153is installed between the processing container120and the resonant coil132. The gas guide153surrounds the outer wall of the processing container120. The gas guide153is configured to guide the temperature controlling gas between the processing container120and the resonant coil132through the gas introduction hole152a. A part of the gas flow path140is formed between the processing container120and the gas guide153. The temperature controlling gas efficiently flows between the processing container120and the resonant coil132. The gas guide153is fixed to the base plate148, the reaction tube131or the shield unit152.

For example, the gas guide153has the following shape. An intermediate portion153bis installed to surround the processing container120. The intermediate portion153bhas, for example, a cylindrical shape. A flange unit153ais installed at the gas introduction hole152aside of the intermediate portion153b. The flange unit153acomes in contact with a lower end of the intermediate portion153b. The flange unit153ais installed to suppress the temperature controlling gas from leaking between the gas guide153and the shield unit152. The flange unit153ais installed between the gas introduction hole152aand a lower end of the resonant coil132. The flange unit153ais installed below the opening166afor the movable tap166. The flange unit153aextends to the outside from the intermediate portion153bin a diameter direction. An end at the shield unit152side within the flange unit153ais installed in a substantially arc shape along a shape inside the shield unit152. The temperature controlling gas mainly flows between the gas guide153and the processing container120at a high speed, rather than between the gas guide153and the shield unit152. Therefore, the processing container120is efficiently cooled.

A flange unit153cis installed at a side opposite to the flange unit153aof the intermediate portion153b. The flange unit153ccomes in contact with an upper end of the intermediate portion153b. The flange unit153cis installed above the opening162aof the movable tap162. The temperature controlling gas is mainly exhausted between the gas guide153and the processing container120rather than between the gas guide153and the shield unit152.

The gas guide153mainly includes the flange unit153aand the intermediate portion153b. Also, the flange unit153cmay be included in the gas guide153. Also, the flange unit153a, the intermediate portion153band the flange unit153cneed not be clearly separated.

Here, when an outer diameter of the reaction tube131of the processing container120is set to φc, an inner diameter (an inner diameter of the intermediate portion153b) of the gas guide153is set to φg, and an inner diameter of the shield unit152is set to φs, an interval dcgbetween the processing container120and the gas guide153and an interval dgsbetween the gas guide153and the shield unit152are obtained by the following equations. Also, a thickness of the gas guide153is set to a degree that is negligible with respect to the inner diameter and the outer diameter. An inner diameter of the gas guide153is set to be the same as an outer diameter of the gas guide153.
dcg(φg−φc)/2,dgs(φs−φg)/2

As a width of the gas flow path140decreases, a flow velocity of the temperature controlling gas increases. As the flow velocity of the temperature controlling gas increases, a heat transfer rate between the temperature controlling gas and the processing container120increases. Therefore, the interval dcgbetween the processing container120and the gas guide153is preferably smaller than the interval dgsbetween the gas guide153and the shield unit152. That is, dcg<dg, is preferable. A flow velocity of the temperature controlling gas between the processing container120and the gas guide153is higher than a flow velocity of the temperature controlling gas at other parts of the gas flow path140. Therefore, a heat transfer rate increases between the temperature controlling gas and the processing container120.

Also, when forced convection of the temperature controlling gas is not performed, natural convection may occur in an enclosed space between the shield unit152and the processing container120. In natural convection, a heat transfer rate among the processing container120, the enclosed space and the processing container120may be 5 W/m2K or more and 20 W/m2K or less.

Meanwhile, when forced convection due to the temperature controlling gas is performed as in the present embodiment, a heat transfer rate between the temperature controlling gas and the processing container120may be 25 W/m2K or more and 250 W/m2K or less. In order to stabilize a temperature of the processing container120, a heat transfer rate of the processing container120of at least several tens of W/m2K or more is required. As a flow velocity at a part between the processing container120and the shield unit152within the gas flow path140, several tens of msec or more is required. In order to satisfy these requirements, the interval dcgbetween the gas guide153and the processing container120is preferably, for example, 2 mm or more and 5 mm or less. Therefore, the above heat transfer rate is implemented.

Also, when a diameter of an end at the shield unit152side within the flange unit153ais set to φf, the interval dfs[that is, an interval dfsat a gap between the flange unit153aand the shield unit152] between the end of the flange unit153aand the shield unit152is obtained by the following equation.
dfs=(φs−φf)/2

The interval dfsbetween the end of the flange unit153aand the shield unit152is negligibly small, compared to the interval dcgbetween the processing container120and the gas guide153. That is, dfs<<dcgis established. Therefore, it is possible to suppress the temperature controlling gas from leaking between the gas guide153and the shield unit152.

The flange unit153ais positioned above the gas introduction hole152a. A height from the base plate148to the flange unit153ais, for example, 20 mm or more and 50 mm or less.

The gas guide153has a thickness of, for example, 2 mm or more and 5 mm or less. When the thickness of the gas guide153is within the above range, a capacitance capacity Cp between the resonant coil132and the shield unit152is not easily influenced by insertion of the gas guide153. Also, when plasma processing is performed, the gas guide153is not easily changed due to heat from the processing container120.

The gas guide153is made of, for example, a material of a low dielectric constant. For example, the material of the gas guide153has a lower dielectric constant than a material of the reaction tube131. When the reaction tube131is made of quartz (dielectric constant is 3.8), a dielectric constant of the gas guide153is, for example, 3.8 or less. Therefore, the capacitance capacity Cp between the resonant coil132and the shield unit152is not easily influenced by insertion of the gas guide153.

Also, the gas guide153may be made of, for example, an insulating material. On the other hand, when the gas guide153has conductivity, an inside of the reaction tube131is electrically shielded by the gas guide153. When the gas guide153is made of an insulating material, it is difficult to decrease plasma generation in the reaction tube131.

Also, the gas guide153may be made of, for example, a material having thermal resistance. The gas guide153is closer to the reaction tube131than to the resonant coil132. The gas guide153may be heated to, for example, about 200° C. When the gas guide153is made of a polymeric material, a material glass transition temperature of the gas guide153is, for example, 200° C. or more. Therefore, the gas guide153keeps its shape when plasma processing is performed.

Specifically, the gas guide153is made of any material of Teflon (registered trademark), polytetrafluoroethylene (PTFE), polychlorotrifluoroethylene (PCTFE), polyether ether ketone (PEEK), polyoxymethylene (POM), Vespel (registered trademark) and polybenzimidazole (PBI). In this case, the gas guide153satisfies above-described requirements of the dielectric constant, the insulating property and the thermal resistance.

An intermediate opening156is installed above at least the resonant coil132. For example, the intermediate opening156is installed on the top plate154. The intermediate opening156is installed between the resonant coil132and the gas exhaustion hole185to be described below within the gas flow path140. The intermediate opening156connects a part between the processing container120and the shield unit152and a gas buffer unit182to be described below. The intermediate opening156is installed, for example, outside an upper end of a cylindrical part of the reaction tube131.

Also, when the reaction tube131includes an extending part (a reference numeral is not shown) that extends from a cylindrical part in a diameter direction, the intermediate opening156may also be installed in the extending part. In this case, the intermediate opening156communicates with the extending part of the reaction tube131and the top plate154.

For example, a plurality of intermediate openings156are installed. The plurality of intermediate openings156are installed in an annular shape to surround the processing container120. The plurality of intermediate openings156are disposed in the circumferential direction of the processing container120within the gas flow path140at equal intervals. The plurality of intermediate openings156each are installed at a position that each of the plurality of gas introduction holes152aoverlaps, for example, in a birds-eye view of the plasma processing apparatus10. The temperature controlling gas is introduced through the plurality of gas introduction holes152a, and flows toward the plurality of intermediate openings156. The plurality of intermediate openings156each have substantially a circular shape.

The gas buffer unit (air pumping box)182is installed vertically above the processing container120. The gas buffer unit182is disposed above the top plate154. The gas buffer unit182is installed between the intermediate opening156and the gas exhaustion hole185to be described below within the gas flow path140. The gas buffer unit182is installed downstream [the gas exhaustion hole185side to be described below] from the resonant coil132within the gas flow path140.

The gas buffer unit182is connected to all of the plurality of intermediate openings156. The gas buffer unit182is designed not to interfere with advancing of the temperature controlling gas. A conductance in the gas buffer unit182is greater than a conductance of a space between the gas introduction hole152aand the gas buffer unit182. A volume in the gas buffer unit182is greater than a volume of a space between the gas guide153and the processing container120.

The gas buffer unit182may have a columnar shape, a polygonal columnar shape, a cone shape or a polygonal cone shape. A bottom of the gas buffer unit182has a diameter of, for example, 450 mm or more and 550 mm or less.

A height of the gas buffer unit182is higher than a diameter of the intermediate opening156. The height of the gas buffer unit182is, for example, 50 mm or more and 200 mm or less. Therefore, when the temperature controlling gas is introduced into the gas buffer unit182through the intermediate opening156, it is difficult to interfere with a flow toward the gas exhaustion hole185.

The gas exhaustion hole185is installed vertically above the processing container120. The gas exhaustion hole185is configured to exhaust the temperature controlling gas from the gas flow path140. The gas exhaustion hole185is installed at a side opposite to the intermediate opening156of the gas buffer unit182. The gas exhaustion hole185is disposed at the center of the gas buffer unit182in a birds-eye view of the plasma processing apparatus10. The plurality of intermediate openings156are disposed from the gas exhaustion hole185at equal distances. More preferably, the plurality of intermediate openings156are disposed point-symmetrically with respect to the center of the gas buffer unit182in a birds-eye view of the plasma processing apparatus10. The temperature controlling gas flows toward the center of the processing container120from each of the intermediate openings156in a diameter direction in a birds-eye view of the plasma processing apparatus10. Therefore, a flow velocity of the temperature controlling gas at a part along the outer wall of the processing container120is likely to be uniformized in the circumferential direction.

(Gas Exhaustion Pipe and Exhaust Device)

A gas exhaustion pipe186is connected to the gas exhaustion hole185. The exhaust device188is connected to a side opposite to the gas exhaustion hole185of the gas exhaustion pipe186. The exhaust device188forcefully exhausts the temperature controlling gas through the gas exhaustion hole185to form the gas flow path140from the gas introduction hole152ato the gas exhaustion hole185within the gas flow path140. Also, the exhaust device188is not necessarily installed as a dedicated product of the plasma processing apparatus10. The exhaust device188may be a common duct installed in a cleanroom.

An adjusting valve (control damper)184is installed at the gas exhaustion pipe186. The adjusting valve184is configured to adjust a flow rate of the temperature controlling gas flowing in the gas exhaustion pipe186. The adjusting valve184decreases (dumps) a flow rate of the temperature controlling gas when a constant amount of the temperature controlling gas is exhausted. The adjusting valve184is a damper.

A flow rate of the temperature controlling gas flowing in the gas flow path140is, for example, 1 m3/min or more and 10 m3/min or less. The gas exhaustion hole185has an inner diameter of, for example, 50 mm or more and 100 mm or less. Also, an inner diameter of the gas exhaustion pipe186is the same as, for example, the inner diameter of the gas exhaustion hole185.

(Gas Flow Path of Temperature Controlling Gas)

For example, the plurality of gas introduction holes152a, the gas guide153, the plurality of intermediate openings156, the gas buffer unit182and the gas exhaustion hole185constitute the gas flow path140of the temperature controlling gas. The temperature controlling gas flows in order thereof. Also, the gas exhaustion pipe186, the adjusting valve184and the exhaust device188may be included in the gas flow path140.

The plurality of gas introduction holes152aare disposed in the circumferential direction of the processing container120within the gas flow path140at equal intervals. The temperature controlling gas is uniformly introduced through the plurality of gas introduction holes152ain the circumferential direction. Therefore, the processing container120is likely to be uniformly cooled in the circumferential direction due to the temperature controlling gas.

The gas guide153is installed between the processing container120and the resonant coil132to surround the outer wall of the processing container120. Therefore, the gas flow path140becomes narrower at a part along the processing container120by the gas guide153. The temperature controlling gas flows at a high speed between the processing container120and the resonant coil132. Therefore, cooling of the processing container120is facilitated.

The plurality of intermediate openings156are installed between the resonant coil132and the gas exhaustion hole185. The plurality of intermediate openings156are disposed in the circumferential direction of the processing container120within the gas flow path140at equal intervals. The temperature controlling gas is introduced through the plurality of gas introduction holes152aand flows toward the plurality of intermediate openings156. A flow rate and a flow velocity of the temperature controlling gas are uniformized between the gas introduction hole152aand the intermediate opening156in the circumferential direction. Therefore, the processing container120is likely to be uniformly cooled in the circumferential direction due to the temperature controlling gas.

The gas buffer unit182is installed between the intermediate opening156and the gas exhaustion hole185. A conductance in the gas buffer unit182is greater than a conductance of a space between the gas introduction hole152aand the intermediate opening156. Therefore, when the temperature controlling gas is introduced into the gas buffer unit182, it is difficult to interfere with a flow toward the gas exhaustion hole185.

The gas exhaustion hole185is installed at a side opposite to the intermediate opening156of the gas buffer unit182. Only one gas exhaustion hole185is disposed at the center of the plurality of intermediate openings156in a birds-eye view of the plasma processing apparatus10. A flow velocity at a part between the gas introduction hole152aand the intermediate opening156within the gas flow path140is uniformized in the circumferential direction of the processing container120. Therefore, the processing container120is likely to be uniformly cooled in the circumferential direction.

In this manner, the temperature controlling gas is introduced through the gas introduction hole152a, and is exhausted from the gas exhaustion hole185through the outer wall of the processing container120. Here, the temperature controlling gas flows in a direction opposite to that of the processing gas. The temperature controlling gas flows from the lower side to the upper side of the processing container120. That is, the temperature controlling gas flows from the exhaust system side of the processing container120to the gas supply system of the processing container120. A part of the gas flow path140is formed in a length direction of the reaction tube131. The outer wall of the processing container120is cooled due to the temperature controlling gas. On the other hand, the temperature controlling gas is heated by the outer wall of the processing container120. The temperature controlling gas may flow in the same direction of an ascending air current due to the heat.

(Control of Temperature Controlling Gas)

The controller170serving as a control unit is connected to the adjusting valve184. The controller170is configured to control a flow rate of the temperature controlling gas by adjusting a degree of opening of the adjusting valve184. For example, when a temperature of the processing container120is lower than a predetermined temperature, the controller170decreases a degree of opening of the adjusting valve184. Therefore, the temperature of the processing container120increases to the predetermined temperature. On the other hand, when the temperature of the processing container120is greater than the predetermined temperature, the controller170increases the degree of opening of the adjusting valve184. Therefore, the temperature of the processing container120decreases to the predetermined temperature. In this manner, the temperature of the processing container120remains in the predetermined temperature.

Also, the term “temperature of the processing container120” used herein refers to a temperature of the outer wall of the processing container120and a temperature inside the processing container120. Also, the term “predetermined temperature” used herein may refer to a constant temperature range in which a rate of plasma processing or a degree of plasma processing becomes a predetermined rate or a predetermined degree.

A temperature measurement unit183is installed in the gas flow path140. The temperature measurement unit183penetrates through, for example, the shield unit152, and comes in contact with the processing container120. The temperature measurement unit183penetrates through the shield unit152and comes in contact with an outer wall of the reaction tube131. The temperature measurement unit183is configured to measure a temperature of the processing container120. The temperature measurement unit183is disposed downstream from the resonant coil132of the gas flow path140. The temperature measurement unit183is, for example, a type K thermocouple (TC) or a platinum resistance temperature detector (RTD).

The temperature measurement unit183may be installed to be pressed to the processing container120with a constant force due to a spring structure. Even when an installation state is changed due to thermal expansion, the temperature measurement unit183and the processing container120remain in contact. Therefore, the temperature measurement unit183can stably measure the temperature of the processing container120.

The controller170serving as a control unit is connected to the temperature measurement unit183. The controller170is configured to control the adjusting valve184based on temperature information from the temperature measurement unit183. The temperature of the processing container120remains in the predetermined temperature.

(3) Plasma Processing Method

FIG. 3is a flowchart illustrating a plasma processing method according to an embodiment of the present invention. As a process among processes of manufacturing a semiconductor device, a plasma processing process according to the present embodiment will be described with reference toFIG. 3. Hereinafter, for example, a case in which a resist film applied onto the wafer20is ashed will be described. The plasma processing process is performed by the above-described plasma processing apparatus10. In the following description, operations of respective units of the plasma processing apparatus10are controlled by the controller170.

A pod (not illustrated) including, for example, 25 wafers20, is transferred to the loadlock seal (not illustrated) of the plasma processing apparatus10. A processing surface of each of the wafers20is coated with, for example, a resist film (S101).

The exhaust device188is operated to start exhaustion of the temperature controlling gas in the gas flow path140. The temperature controlling gas is introduced into the gas flow path140through the gas introduction holes152adisposed in the circumferential direction of the processing container120at equal intervals. The controller170controls a flow rate of the temperature controlling gas by adjusting a degree of opening of the adjusting valve184based on temperature information from the temperature measurement unit183. For example, when the temperature of the processing container120is lower than the predetermined temperature, for example, when processing starts, the controller170decreases a degree of opening of the adjusting valve184or a flow rate of the temperature controlling gas is set to be smaller. Also, flow rate control of the temperature controlling gas is continuously performed, for example, until the plasma processing process ends (S102).

Next, the transfer unit picks up one wafer20from the loadlock seal and loads the wafer20in the processing chamber145. The lift pin113is raised by the lifting shaft173, and the wafer20is placed on the lift pin113. The transfer unit is extracted from the processing chamber145. The lift pin113is lowered by the lifting shaft173and the wafer20is lowered to a predetermined processing position. Therefore, the wafer20is moved onto the susceptor table111(S103).

(Temperature Adjustment and Pressure Adjustment)

The inside of the processing container120is vacuum-exhausted by the exhaust device179such that the inside of the processing container120has a predetermined pressure (degree of vacuum). In this case, the controller170controls a pressure in the processing container120by adjusting a degree of opening of the APC valve181based on pressure information of the inside of the processing container120, which is measured by the pressure sensor. The pressure of the inside of the processing container120is controlled to be a predetermined pressure within a range, for example, 30 Pa to 530 Pa. Also, the exhaust device179is continuously operated during at least the plasma processing process. Also, control of the pressure of the inside of the processing container120is continuously performed during at least the plasma processing process.

Also, the susceptor159is heated by the heater163such that the temperature of the wafer20becomes a predetermined temperature. Heat adjustments is performed such that the wafer20has a predetermined processing temperature in a range of, for example, 180° C. to 250° C., due to thermal conductivity from the susceptor table111or radiation from the heater163. Also, temperature control of the wafer20is continuously performed during at least the plasma processing process (S104).

Next, when the temperature of the wafer20increases to a predetermined temperature, the gas supply system supplies the processing gas into the processing container120. Specifically, the valve52aof the processing gas supply system is opened, and the processing gas is supplied into the processing container120while a flow rate of the processing gas is adjusted by the mass flow controller52b. The processing gas supplied into the processing container120is dispersed by the dispersion plate160and flows downward along the inner wall of the reaction tube131.

When the processing gas is supplied, plasma of the processing gas is generated by the plasma generating unit at the same time. Specifically, high frequency power is applied to the resonant coil132from the high frequency power source144. As a result, plasma discharge is generated in the plasma generating region130and thus the processing gas becomes a plasma state. The processing gas in a plasma state flows toward the processing chamber145from the plasma generating region130and is supplied to the wafer20. As a result, the resist film formed on the processing surface of the wafer20is ashed.

As the processing gas, for example, at least any of O2gas, H2gas, N2gas, Ar gas, He gas, tetrafluoromethane (CF4) gas and trifluoromethane (CHF3) gas or a combination thereof is used. Also, a flow rate of the processing gas is adjusted within a range of, for example, 800 sccm to 2,600 sccm, by the mass flow controller52b. Also, a processing pressure is set within a range of, for example, 30 Pa to 530 Pa. Also, high frequency power applied to the resonant coil132is set within a range of, for example, 600 W to 2,000 W. Also, a transmission frequency of the high frequency power source144is bound to a resonant frequency of the resonant coil132. In this case, the RF sensor168monitors a reflected wave from the resonant coil132and transmits a level of the monitored reflected wave to the frequency matching unit146. The frequency matching unit146adjusts the transmission frequency of the high frequency power source144such that a reflected wave of reflected wave power is minimized. Therefore, even when a gas flow rate, a gas mixture ratio, and processing conditions of the pressure are changed, the transmission frequency of the high frequency power source144immediately matches.

During plasma processing, for example, when the temperature of the processing container120is higher than a predetermined temperature, a degree of opening of the adjusting valve184is set to be higher. A flow rate of the temperature controlling gas increases. Therefore, the temperature of the processing container120decreases to the predetermined temperature. On the other hand, when the temperature of the processing container120is lower than the predetermined temperature, a degree of opening of the adjusting valve184is set to be lower. Therefore, the temperature of the processing container120increases to the predetermined temperature. In this manner, the temperature of the processing container120remains in the predetermined temperature.

When the resist film on the processing surface of the wafer20is removed, power supply from the high frequency power source144to the resonant coil132is stopped. Also, supply of the processing gas from the gas supply system to the processing container120is stopped. Therefore, plasma processing on the wafer20ends (S105).

(Purging and Restoring to Atmospheric Pressure)

Next, after power supply to the resonant coil132and supply of the processing gas are stopped, the APC valve181is fully opened and the inside of the processing container120is exhausted for a predetermined time. In this case, the valve51aof the purge gas supply system is opened, and the purge gas is supplied into the processing container120while a flow rate of the purge gas is adjusted by the mass flow controller51b. Therefore, the inside of the processing container120is replaced with the purge gas. Also, a degree of opening of the APC valve181is adjusted and the inside of the processing container120is restored to atmospheric pressure (S106).

Next, the processed wafer20is unloaded from the inside of the processing chamber145. The processed wafer20is returned to the pod (S107).

(Determination of Batch Process End)

Next, it is determined whether plasma processing on a predetermined number of wafers20is completely performed (S108). The predetermined number refers to, for example, the number of wafers20accommodated in the pod installed in the plasma processing apparatus10, for example, 25 wafers.

When plasma processing on the predetermined number of wafers20is not completely performed (No in S108), similarly, step (S103) to step (S107) are performed again.

When plasma processing on the predetermined number of wafers20is completely performed (Yes in S108), the exhaust device188is stopped. Therefore, a temperature controlling gas flow is stopped (S109). In this manner, until plasma processing on the predetermined number of wafers20is performed, the temperature controlling gas continuously flows in the gas flow path140.

The pod including the processed wafer20is unloaded from the plasma processing apparatus10(S110). In this manner, the plasma processing process in the present embodiment ends.

(4) Effects of the Present Embodiment

According to the present embodiment, one or a plurality of effects to be described will be obtained.

(a) According to the present embodiment, the gas flow path140is installed at least between the processing container120and the resonant coil132of the plasma generating unit. The temperature controlling gas flows along the outer wall of the processing container120by the gas flow path140. The plurality of gas introduction holes152aare uniformly disposed in the circumferential direction of the processing container120within the gas flow path140and introduce the temperature controlling gas into the gas flow path140. The temperature controlling gas is uniformly introduced through the plurality of gas introduction holes152ain the circumferential direction of the processing container120. The processing container120is uniformly cooled in the circumferential direction due to the temperature controlling gas. The temperature of the processing container120is uniformized in the circumferential direction. A temperature distribution of the wafer20itself is uniformly maintained in the planar direction or a plasma density of the plasma generating region130is uniformly maintained in the planar direction of the wafer20. Therefore, plasma processing is uniformly performed within planes of the wafer20. Uniformity of a rate of plasma processing or a degree of plasma processing within planes of the wafer20increases.

Here, as a first comparative example, a case in which the gas introduction holes152aare non-uniformly disposed in the gas flow path140will be described with reference toFIGS. 4aand 4b.FIG. 4ais a diagram schematically illustrating a temperature distribution of the processing container120according to an embodiment of the present invention.FIG. 4bis a diagram schematically illustrating a temperature distribution of the processing container120according to the first comparative example. InFIGS. 4aand 4b, a solid arrow indicates a flow of the temperature controlling gas. Also, inFIGS. 4aand 4b, a contrast distribution of the reaction tube131illustrates a temperature distribution of the reaction tube131.

As illustrated inFIG. 4b, in the first comparative example, for example, a gas introduction hole152a′ is installed in only a part of the shield unit (not illustrated). Only a part of an outer wall of a reaction tube131′ is cooled. In the first comparative example, a low temperature region LT is more localized than a high temperature region HT. A temperature of the reaction tube131′ is non-uniformized in the circumferential direction. In this case, a temperature distribution of the wafer itself is non-uniformized in the planar direction in some cases or a plasma density of the plasma generating region is non-uniformized in the planar direction of the wafer in some cases. A rate of plasma processing or a degree of plasma processing at a part at which the temperature of the reaction tube131′ is low is lower than a rate of plasma processing or a degree of plasma processing at a part at which the temperature of the reaction tube131′ is high. Accordingly, plasma processing within planes of the wafer may be non-uniformized.

However, according to the present embodiment ofFIG. 4a, the reaction tube131is uniformly cooled in the circumferential direction due to the temperature controlling gas. In the present embodiment, similarly to the high temperature region HT, the low temperature region LT is uniformly distributed in the circumferential direction of the reaction tube131. Therefore, uniformity of plasma processing within planes of the wafer increases.

(b) According to the present embodiment, the controller170serving as a control unit controls a flow rate of the temperature controlling gas by adjusting a degree of opening of the adjusting valve184installed at the gas exhaustion pipe186. The temperature of the processing container120remains in the predetermined temperature. Therefore, it is possible to suppress a rate of plasma processing or a degree of plasma processing from being changed over time during processing or for each processing. Accordingly, uniformity of plasma processing between the wafers20increases.

Here, as a second comparative example, a case in which a controller does not control a flow rate of the temperature controlling gas will be described. In the second comparative example, heat dissipation from the processing container includes only natural convection in a gap between the shield unit and the processing container or radiation from the processing container. When plasma processing is performed, the temperature of the processing container can increase over time. For example, when plasma processing is performed on one wafer, a temperature of the processing container when processing ends becomes higher than a temperature of the processing container when processing starts. Also, when plasma processing is consecutively performed on a plurality of wafers, a temperature of the processing container when processing is performed on the plurality of wafers is higher than a temperature of the processing container when processing is performed on a first wafer. In this case, a temperature of the wafer can be changed over time or a plasma density of the plasma generating region can be changed over time. Accordingly, a rate of plasma processing or a degree of plasma processing may be changed over time during processing or for each processing. However, according to the present embodiment, the temperature of the processing container remains in the predetermined temperature by the controller170. Therefore, it is possible to suppress a rate of plasma processing or a degree of plasma processing from being changed over time during processing or for each processing.

(c) According to the present embodiment, the gas buffer unit182is installed between the plasma generating unit and the gas exhaustion hole185within the gas flow path140. A conductance in the gas buffer unit182is greater than a conductance of a space between the gas introduction hole152aand the gas buffer unit182. Therefore, when the temperature controlling gas is introduced into the gas buffer unit182, it is difficult to interfere with a flow toward the gas exhaustion hole185. The temperature controlling gas heated by the processing container120is efficiently exhausted from the gas buffer unit182to the gas exhaustion hole185.

(d) According to the present embodiment, the plurality of intermediate openings156are installed between the plasma generating unit and the gas exhaustion hole185within the gas flow path140, and are uniformly disposed in the circumferential direction of the processing container120within the gas flow path140. The plurality of intermediate openings156are disposed from the gas exhaustion hole185at equal distances. A flow velocity at a part between the gas introduction hole152aand the intermediate opening156within the gas flow path140is uniformized in the circumferential direction of the processing container120. Therefore, the processing container120is likely to be uniformly cooled in the circumferential direction.

(e) According to the present embodiment, the gas guide153is installed between the processing container120and the resonant coil132of the plasma generating unit and guides the temperature controlling gas between the processing container120and the resonant coil132of the plasma generating unit through the gas introduction hole152a. A part of the gas flow path140is installed between the processing container120and the gas guide153. The gas flow path140becomes narrower at a part along the processing container120by the gas guide153. Even when the temperature controlling gas has a similar flow rate, the temperature controlling gas flows at a high speed between the processing container120and the resonant coil132. Since a heat transfer rate between the temperature controlling gas and the processing container120increases as a flow velocity of the temperature controlling gas increases, cooling of the processing container120is facilitated.

(f) According to the present embodiment, plasma processing is performed on the predetermined number of wafers20, and the temperature controlling gas continuously flows in the gas flow path140until plasma processing is performed on the predetermined number of wafers20. During the process, the temperature of the processing container120remains in the predetermined temperature. Plasma processing on each of the wafers20is performed while the temperature of the processing container120is the predetermined temperature. Therefore, it is possible to suppress a rate of plasma processing or a degree of plasma processing from being changed over time during processing or for each processing.

Here, as a method of stabilizing the temperature of the processing container120, a case in which the processing container120is pre-heated before the plasma processing process or a case in which a cooling time is set when the processing container120is heated may be considered. However, in any case, an additional time is consumed. Throughput may decrease. However, according to the present embodiment, the temperature of the processing container120remains in the predetermined temperature. It is possible to suppress a rate of plasma processing or a degree of plasma processing from being changed over time during processing or for each processing. Therefore, productivity increases.

−Other Embodiments of the Present Invention

Embodiments of the present invention have been specifically described above. The present invention is not limited to the above-described embodiments, but may be variously changed without departing from the scope of the invention.

In the present embodiment, the object to be processed has been described as the wafer20before processing. The object to be processed may be a semiconductor device or a semiconductor package after processing.

In the present embodiment, a case in which the controller170serving as a control unit controls a flow rate of the temperature controlling gas by adjusting a degree of opening of the adjusting valve184based on temperature information from the temperature measurement unit183has been described. The controller170may control a flow rate of the temperature controlling gas based on a pre-input temperature simulation result. The controller170may control a flow rate of the temperature controlling gas based on a flow rate of the processing gas, power of the high frequency power source144, a processing time and the number of processing times in addition to the simulation result.

In the present embodiment, a method in which the temperature measurement unit183is brought in direct contact with the processing container120to measure a temperature has been described. The temperature measurement unit183may measure a temperature of the temperature controlling gas flowing in the gas flow path140. Also, the temperature measurement unit183may measure a temperature of the processing container120using an infrared thermometer in a non-contact manner.

In the present embodiment, a case in which the plurality of intermediate openings156of the gas flow path140are installed in an annular shape has been described. The intermediate opening156may be a gap having an annular shape (ring shape). The intermediate opening156is preferably disposed concentrically with the processing container120. The gas exhaustion hole185is disposed at the center of the intermediate opening156having an annular shape in a birds-eye view of the plasma processing apparatus10. Therefore, the same effects as in the present embodiment may be obtained.

According to the plasma processing apparatus and the method of manufacturing a semiconductor device of the present invention, it is possible to increase uniformity of plasma processing in a surface to be processed of an object to be processed or increase uniformity of plasma processing between objects to be processed.

PREFERRED EMBODIMENTS OF THE PRESENT INVENTION

Hereinafter, preferred embodiments according to the present invention are supplementarily noted.

According to an aspect of the present invention, there is provided a plasma processing apparatus including:

a processing container configured to accommodate an object to be processed;

a gas supply system configured to supply a processing gas into the processing container;

an exhaust system configured to exhaust an inside atmosphere of the processing container;

a plasma generating unit installed outside the processing container and configured to generate a plasma of the processing gas supplied into the processing container;

a gas flow path installed at least between an outer wall of the processing container and the plasma generating unit, the gas flow path guiding a temperature controlling gas to flow along the outer wall of the processing container;

a plurality of gas introduction holes disposed along a circumferential direction of the processing container and configured to introduce the temperature controlling gas into the gas flow path; and

a gas exhaustion hole configured to exhaust the temperature controlling gas passed through the gas flow path.

In the plasma processing apparatus of Supplementary note 1, preferably, further including:

a gas exhaustion pipe connected to the gas exhaustion hole and configured to exhaust the temperature controlling gas through the gas exhaustion hole;

an adjusting valve installed at the gas exhaustion pipe; and

a control unit configured to control a flow rate of the temperature controlling gas by adjusting an opening degree of the adjusting valve.

According to another aspect of the present invention, there is provided a plasma processing apparatus including:

a processing container configured to accommodate an object to be processed;

a gas supply system configured to supply a processing gas into the processing container;

an exhaust system configured to exhaust an inside atmosphere of the processing container;

a plasma generating unit installed outside the processing container and configured to generate a plasma of the processing gas supplied into the processing container;

a gas flow path installed between an outer wall of the processing container and the plasma generating unit, the gas flow path guiding a temperature controlling gas to flow along the outer wall of the processing container;

a gas introduction hole configured to introduce the temperature controlling gas into the gas flow path;

a gas exhaustion hole configured to exhaust the temperature controlling gas passed through the gas flow path;

a gas exhaustion pipe connected to the gas exhaustion hole and configured to exhaust the temperature controlling gas through the gas exhaustion hole;

an adjusting valve installed at the gas exhaustion pipe; and

a control unit configured to control a flow rate of the temperature controlling gas by adjusting an opening degree of the adjusting valve.

In the plasma processing apparatus of any one of Supplementary notes 2 and 3, preferably, further including a temperature measurement unit configured to measure a temperature of the processing container, and the control unit is further configured to control the adjusting valve based on a temperature information generated by the temperature measurement unit.

In the plasma processing apparatus of any one of Supplementary notes 1 through 4, preferably, further including a gas buffer unit installed between the plasma generating unit and the gas exhaustion hole, and a conductance of the gas buffer unit is greater than that of a space between the plurality of gas introduction holes and the gas buffer unit.

In the plasma processing apparatus of Supplementary note 5, preferably, the gas buffer unit is disposed on the processing container.

In the plasma processing apparatus of any one of Supplementary notes 5 and 6, preferably, the gas exhaustion hole is installed at the center of the gas buffer unit in a birds-eye view.

The plasma processing apparatus of any one of Supplementary notes 1 to 7, preferably, further includes a plurality of intermediate openings that are installed between the plasma generating unit and the gas exhaustion hole and are uniformly disposed in a circumferential direction of the processing container within the gas flow path, and the plurality of intermediate openings are disposed from the gas exhaustion hole at uniform distances.

The plasma processing apparatus of any one of Supplementary notes 1 to 8, preferably, further includes a shield unit that is installed to surround an outside of the plasma generating unit, includes the gas introduction hole and has conductivity, and a part of the gas flow path is installed at least between the processing container and the shield unit.

In the plasma processing apparatus of any one of Supplementary notes 1 through 9, preferably, further including a gas guide disposed between the processing container and the plasma generating unit to surround the outer wall of the processing container wherein the gas guide is configured to guide the temperature controlling gas introduced through the plurality of gas introduction holes to flow between the processing container and the plasma generating unit, and wherein the gas flow path is installed between the processing container and the gas guide unit.

In the plasma processing apparatus of any one of Supplementary note 10, preferably, the gas guide is formed of a material having a low dielectric constant.

In the plasma processing apparatus of any one of Supplementary notes 10 and 11, preferably, the gas guide is formed of an insulating material.

In the plasma processing apparatus of any one of Supplementary notes 10 through 12, preferably, the gas guide is formed of a material having heat resistance.

The plasma processing apparatus of any one of Supplementary notes 10 to 13, preferably, further includes a shield unit that is installed to surround an outside of the plasma generating unit, includes the gas introduction hole and has conductivity, and an interval between the gas guide and the processing container is smaller than an interval between the gas guide and the shield unit.

In the plasma processing apparatus of any one of Supplementary notes 10 to 14, preferably, the gas guide includes an intermediate portion installed to surround the processing container; and a flange unit that comes in contact with the gas introduction hole side within the intermediate portion and is installed to suppress the temperature controlling gas from being introduced between the gas guide and the shield unit.

In the plasma processing apparatus of Supplementary note 15, preferably, the flange unit extends to the outside from the intermediate portion in a diameter direction.

In the plasma processing apparatus of any one of Supplementary notes 10 through 16, preferably, the gas guide is formed of one of a material selected from the group consisting of Teflon (registered trademark), PTFE (polytetrafluoroethylene), PCTFE (polychlorotrifluoroethylene), PEEK (Polyether ether ketone), POM (polyoxymethylene), Vespel (registered trademark) and PBI (polybenzimidazole).

In the plasma processing apparatus of any one of Supplementary notes 1 through 17, preferably, the temperature controlling gas includes at least one of an air and a nitrogen gas.

In the plasma processing apparatus of any one of Supplementary notes 1 through 18, preferably, the plurality of gas introduction holes are disposed along the circumferential direction of the processing container at equal intervals.

According to another aspect of the present invention, there is provided a method of manufacturing a semiconductor device, including:

(a) loading an object to be processed into a processing container;

(b) introducing a processing gas into the processing container, generating plasma of the processing gas supplied into the processing container using the plasma generating unit installed outside the processing container, and subjecting the object to a plasma processing; and

(c) introducing a temperature controlling gas into a gas flow path through a plurality of gas introduction holes disposed along a circumferential direction of the processing container, wherein the gas flow path is installed at least between an outer wall of the processing container and the plasma generating unit along the outer wall of the processing container.

According to still another aspect of the present invention, there is provided a method of manufacturing a semiconductor device, including:

(a) loading an object to be processed into a processing container;

(b) introducing a processing gas into the processing container and generating plasma of the processing gas supplied into the processing container using the plasma generating unit installed outside the processing container, and subjecting the object to a plasma processing; and

(c) introducing a temperature controlling gas into a gas flow path installed at least between an outer wall of the processing container and the plasma generating unit along the outer wall of the processing container and controlling a flow rate of the temperature controlling gas such that the processing container is at a predetermined temperature.

In the method of manufacturing a semiconductor device of any one of Supplementary notes 20 and 21, preferably, (b) is performed to a predetermined number of objects to be processed and (c) is performed while performing (b) to the predetermined number of the objects to be processed.

In the method of manufacturing a semiconductor device of any one of Supplementary notes 20 through 22, preferably, the temperature controlling gas is introduced into the gas flow path through the plurality of gas introduction holes disposed along the circumferential direction of the processing container at equal intervals.

According to the substrate processing apparatus and the method of manufacturing a semiconductor device of the present invention, it is possible to increase uniformity of plasma processing in a surface to be processed of an object to be processed or increase uniformity of plasma processing between objects to be processed.