JP2010123624A - Wafer treatment apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce an influence of an erosion gas applied to the metal of a rotating shaft. <P>SOLUTION: In the wafer treatment apparatus including a treatment chamber 201 which treats a wafer 200, a boat 217 which supports the wafer 200 in the treatment chamber 201, a seal cap 219 which closes the treatment chamber 201, a rotating shaft 255 which rotates the boat 217, an erosion gas supply nozzle 230a which supplies the erosion gas into the treatment chamber 201, and a non-erosion gas supply nozzle 230b which supplies a non-erosion gas into the treatment chamber 201, a shaft protector 301 which covers the rotating shaft 255 while facing the gas jetting ports of the erosion gas supply nozzle 230a, and non-erosion gas supply nozzle 230b is provided above the seal cap 219, and an opening 302 is formed in the shaft protector 301 at a part facing the gas jetting port of the non-erosion gas supply nozzle 230b. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a substrate processing apparatus for forming a film on a substrate such as a semiconductor wafer or a glass substrate.

When a substrate processing apparatus such as a vertical film forming processing apparatus is used to form a film that is a plurality of wafers, an L-shaped nozzle is used as a rotating shaft protection structure or the material of the rotating shaft metal is changed. The technique of doing is known.
Further, it is a process of forming a Si3 N4 film on a substrate using SiH2 Cl2 and NH3 by a vertical thermal CVD apparatus, a plate-like member is provided between the inside of the reaction furnace and the furnace opening, and NH3 is added. By supplying SiH2Cl2 separately from the downstream side from the upstream side of the plate member, NH3 is an inert gas in a structure that prevents adhesion of by-products such as NH4Cl to the low temperature part such as the furnace opening. There is also a method of preventing the corrosion of the metal at the furnace opening by replacing with. For example, see Patent Document 1.

International Publication No. 2004/075272 Pamphlet

In a substrate processing apparatus that supplies reaction gas into a reaction furnace through a nozzle, when supplying the reaction gas in a film forming process, the nozzle position in the reaction furnace is a rotation that a boat that holds the substrate of the apparatus has. Since it hits the same height as the shaft, the gas blown out from the nozzle flows into the rotating shaft in a fluid and diffusive manner. Thereby, there is a concern that the rotating shaft metal is affected by the corrosive gas, generates a contamination source, and affects the processing substrate.
Therefore, as a countermeasure, a technique for prefilling the reactor with a non-corrosive gas under reduced pressure and a technique for employing a corrosion-resistant metal for the rotating shaft are conceivable. Although these techniques can avoid significant impacts, they are not perfect and we assume that concerns remain.
In addition, the flow of the reaction gas can be changed by changing the nozzle shape to an L shape, but there is a problem that it is not suitable when the clearance between the inner wall of the reaction furnace and the boat as the substrate support is narrow.

  An object of the present invention is to provide a substrate processing apparatus capable of solving the countermeasures when the nozzle shape of these problems is limited and reducing the influence of the corrosive gas received on the rotating shaft metal.

  According to one aspect of the present invention, a processing chamber for processing a substrate, a support for supporting the substrate in the processing chamber, a rotating shaft for supporting and rotating the support, and a corrosive gas in the processing chamber. A corrosive gas supply nozzle for supplying, a non-corrosive gas supply nozzle for supplying a non-corrosive gas into the processing chamber, a gas outlet of the corrosive gas supply nozzle, and a gas outlet of the non-corrosive gas supply nozzle And a cover member provided so as to cover the rotating shaft while facing the gas outlet, and having an opening provided in a portion facing the gas ejection port of the non-corrosive gas supply nozzle.

  ADVANTAGE OF THE INVENTION According to this invention, it can prevent that corrosive gas flows in into a rotating shaft directly as a protective structure of a rotating shaft. Thereby, generation | occurrence | production of the contamination source from a rotating shaft metal can be prevented, and the contamination influence to a process board | substrate can be reduced. In addition, when a non-corrosive gas is allowed to flow into the protective device, a baffle plate or the like is provided in the space within the protective device to temporarily stagnate, thereby also promoting the decomposition efficiency of the reaction gas.

  An embodiment of the present invention will be described below with reference to the drawings.

First, the configuration of the substrate processing apparatus according to the present embodiment will be described with reference to the drawings.
FIG. 1 is a schematic configuration diagram of a processing furnace 202 of a substrate processing apparatus preferably used in the present embodiment, and is shown as a longitudinal sectional view.

  As shown in FIG. 1, the processing furnace 202 includes a heater 206 as a heating mechanism. The heater 206 has a cylindrical shape and is vertically installed by being supported by a heater base 251 as a holding plate.

A process tube 203 as a reaction tube is disposed inside the heater 206 concentrically with the heater 206. The process tube 203 includes an inner tube 204 as an internal reaction tube and an outer tube 205 as an external reaction tube provided on the outer side thereof.
The inner tube 204 is made of a heat-resistant material such as quartz (SiO2) or silicon carbide (SiC), and is formed in a cylindrical shape having an upper end and a lower end opened. A processing chamber 201 for performing a process of forming a thin film on a wafer 200 as a substrate is formed in the hollow cylindrical portion of the inner tube 204. The processing chamber 201 is configured such that the wafers 200 can be accommodated in a state where the wafers 200 are arranged in a plurality of stages in the vertical direction in a horizontal posture by a boat 217 described later.
The outer tube 205 is made of, for example, a heat-resistant material such as quartz or silicon carbide, has an inner diameter larger than the outer diameter of the inner tube 204, is formed in a cylindrical shape with the upper end closed and the lower end opened. It is provided concentrically.

A manifold 209 is disposed below the outer tube 205 concentrically with the outer tube 205. The manifold 209 is made of, for example, stainless steel and is formed in a cylindrical shape with an upper end and a lower end opened. The manifold 209 is engaged with the inner tube 204 and the outer tube 205, and is provided so as to support them. An O-ring 220a as a seal member is provided between the manifold 209 and the outer tube 205.
By supporting the manifold 209 on the heater base 251, the process tube 203 is installed vertically. A reaction vessel is formed by the process tube 203 and the manifold 209.

Nozzles 230 a and 230 b as gas introduction portions are connected to the manifold 209 so as to communicate with the inside of the processing chamber 201. Processing gas supply pipes 232a and 232b for supplying a processing gas for forming a thin film into the processing chamber 201 are connected to the nozzles 230a and 230b, respectively.
On the upstream side of the processing gas supply pipe 232a opposite to the connection side with the nozzle 230a, SiH2 Cl2 (DCS) as a first processing gas supply source is provided via a MFC (mass flow controller) 241a as a gas flow rate controller. A gas supply source 271 is connected. Valves 262a and 261a are provided on the upstream side and the downstream side of the processing gas supply pipe 232a from the MFC 241a, respectively.
An upstream side of the processing gas supply pipe 232b opposite to the connection side with the nozzle 230b is an N2 O gas supply source as a second processing gas supply source via an MFC (mass flow controller) 241b as a gas flow rate controller. 272 is connected. Valves 262b and 261b are respectively provided upstream and downstream of the MFC 241b in the processing gas supply pipe 232b.
A processing gas supply system is mainly configured by the processing gas supply pipes 232a and 232b, the MFCs 241a and 241b, the valves 262a, 261a, 262b, and 261b, the SiH2 Cl2 gas supply source 271 and the N2 O gas supply source 272.

Inert gas supply pipes 232c and 232d are connected to the downstream sides of the valves 261a and 261b of the processing gas supply pipes 232a and 232b, respectively.
On the upstream side of the inert gas supply pipe 232c opposite to the connection side with the processing gas supply pipe 232a, N2 gas as an inert gas supply source is provided via an MFC (mass flow controller) 241c as a gas flow rate controller. A supply source 273 is connected. Valves 262c and 261c are provided on the upstream side and the downstream side of the MFC 241c of the inert gas supply pipe 232c, respectively.
An N2 gas supply source 273 is connected to the upstream side of the inert gas supply pipe 232d opposite to the connection side with the processing gas supply pipe 232b via an MFC (mass flow controller) 241d as a gas flow rate controller. Yes. Precisely, the upstream side of the inert gas supply pipe 232d is connected to the upstream side of the valve 262c of the inert gas supply pipe 232c, and the inert gas supply pipe 232d is upstream of the valve 262c. A branch is provided from the supply pipe 232c. Valves 262d and 261d are provided upstream and downstream of the MFC 241d of the inert gas supply pipe 232d, respectively.
An inert gas supply system is mainly constituted by the inert gas supply pipes 232c and 232d, the MFCs 241c and 241d, the valves 262c, 261c, 262d and 261d, and the N2 gas supply source 273.

  The inert gas supply system also has a role of diluting the processing gas, and the inert gas supply system also constitutes a part of the processing gas supply system. The inert gas supply system also functions as a purge gas supply system.

  A gas supply / flow rate controller 235 is electrically connected to the MFCs 241a, 241b, 241c, 241d, valves 261a, 261b, 261c, 261d, 262a, 262b, 262c, 262d. The gas supply / flow rate control unit 235 is configured so that the type of gas supplied into the processing chamber 201 in each step to be described later becomes a desired gas type, and the flow rate of the supplied gas becomes a desired amount. The MFCs 241a, 241b, 241c, and 241d, the valves 261a, 261b, 261c, 261d, 262a, 262b, 262c, and 262d are configured to be controlled at a desired timing so that the concentration of the supplied gas becomes a desired concentration. ing.

The manifold 209 is provided with an exhaust pipe 231 that exhausts the atmosphere in the processing chamber 201. The exhaust pipe 231 is disposed at the lower end portion of the cylindrical space 250 formed by the gap between the inner tube 204 and the outer tube 205 and communicates with the cylindrical space 250. A downstream side of the exhaust pipe 231 opposite to the connection side with the manifold 209 is connected to a pressure sensor 245 as a pressure detector and a pressure adjustment device 242 such as a variable conductance valve, for example, an APC (Auto Pressure Controller) valve. A vacuum exhaust device 246 such as a vacuum pump is connected.
The vacuum exhaust device 246 is configured to be able to perform vacuum exhaust so that the pressure in the processing chamber 201 becomes a predetermined pressure (degree of vacuum). A pressure control unit 236 is electrically connected to the pressure adjusting device 242 and the pressure sensor 245. The pressure control unit 236 is configured to control the pressure adjusting device 242 at a desired timing based on the pressure detected by the pressure sensor 245 so that the pressure in the processing chamber 201 becomes a desired pressure. .
An exhaust system is mainly configured by the exhaust pipe 231, the pressure adjusting device 242, and the vacuum exhaust device 246.

Below the manifold 209, a seal cap 219 is provided as a furnace port lid that can airtightly close the lower end opening of the manifold 209. The seal cap 219 is brought into contact with the lower end of the manifold 209 from the lower side in the vertical direction. The seal cap 219 is made of a metal such as stainless steel and has a disk shape. On the upper surface of the seal cap 219, an O-ring 220b is provided as a seal member that comes into contact with the lower end of the manifold 209.
A rotation mechanism 254 for rotating the boat is installed on the side of the seal cap 219 opposite to the processing chamber 201. A rotation shaft 255 of the rotation mechanism 254 passes through the seal cap 219 and is connected to a boat 217 described later, and is configured to rotate the wafer 200 by rotating the boat 217.
The seal cap 219 is configured to be lifted vertically by a boat elevator 115 as a lifting mechanism vertically installed outside the process tube 203, and thereby the boat 217 is carried into and out of the processing chamber 201. Is possible.
A drive control unit 237 is electrically connected to the rotation mechanism 254 and the boat elevator 115. The drive control unit 237 is configured to control at a desired timing so that the rotation mechanism 254 and the boat elevator 115 perform a desired operation.

The boat 217 serving as a substrate holder is made of a heat-resistant material such as quartz or silicon carbide, and is configured to hold a plurality of wafers 200 in a horizontal posture and in a state where the centers are aligned with each other and held in multiple stages. ing.
In addition, a plurality of heat insulating plates 216 as a disk-shaped heat insulating member made of a heat resistant material such as quartz or silicon carbide are arranged in a plurality of stages in a horizontal posture at the lower part of the boat 217, Heat is configured not to be transmitted to the manifold 209 side.

  A temperature sensor 263 is installed in the process tube 203 as a temperature detector. A temperature controller 238 is electrically connected to the heater 206 and the temperature sensor 263. The temperature control unit 238 controls the power supply to the heater 206 at a desired timing based on the temperature information detected by the temperature sensor 263 so that the temperature in the processing chamber 201 has a desired temperature distribution. It is configured.

  The gas supply / flow rate control unit 235, the pressure control unit 236, the drive control unit 237, and the temperature control unit 238 also constitute an operation unit and an input / output unit, and are electrically connected to the main control unit 239 that controls the entire substrate processing apparatus. It is connected to the. These gas supply / flow rate control unit 235, pressure control unit 236, drive control unit 237, temperature control unit 238, and main control unit 239 are configured as a controller 240.

Next, a method of forming a thin film on the wafer 200 in the processing chamber 201 by the CVD method as one step of the semiconductor device manufacturing process using the processing furnace 202 having the above configuration will be described.
In the following description, the operation of each part constituting the substrate processing apparatus is controlled by the controller 240.

  When a plurality of wafers 200 are loaded into the boat 217 (wafer charge), the boat 217 holding the plurality of wafers 200 is lifted by the boat elevator 115 and loaded into the processing chamber 201 (boat loading). In this state, the seal cap 219 seals the lower end of the manifold 209 via the O-ring 220b.

The processing chamber 201 is evacuated by a vacuum evacuation device 246 so that a desired pressure (degree of vacuum) is obtained. At this time, the pressure in the processing chamber 201 is measured by the pressure sensor 245, and the pressure adjusting device 242 is feedback-controlled based on the measured pressure.
Further, the inside of the processing chamber 201 is heated by the heater 206 so as to have a desired temperature. At this time, the power supply to the heater 206 is feedback-controlled based on the temperature information detected by the temperature sensor 263 so that the temperature in the processing chamber 201 has a desired temperature distribution.
Subsequently, the boat 217 is rotated by the rotation mechanism 254, whereby the wafer 200 is rotated.

Next, with the temperature and pressure in the processing chamber 201 maintained at the desired temperature and pressure, the SiH2 Cl2 gas supply source 271 as the first processing gas supply source and the N2 O gas supply as the second processing gas supply source From the source 272, SiH2Cl2 gas as the first processing gas and N2O gas as the second processing gas are supplied into the processing chamber 201, respectively.
That is, by opening the valves 262a, 261a, 262b, and 261b, the SiH2 Cl2 gas and the N2 O gas supplied from the SiH2 Cl2 gas supply source 271 and the N2 O gas supply source 272 into the processing gas supply pipes 232a and 232b, respectively. Are controlled by the MFCs 241a and 241b so as to obtain a desired flow rate, and then are introduced into the processing chamber 201 from the nozzles 230a and 230b through the processing gas supply pipes 232a and 232b.

At the same time, N2 gas may be supplied from the N2 gas supply source 273 as an inert gas supply source into the processing chamber 201 to dilute the processing gas (SiH2 Cl2 gas, N2 O gas).
In this case, for example, when the valves 262c, 261c, 262d, and 261d are opened, the N2 gas supplied from the N2 gas supply source 273 into the inert gas supply pipes 232c and 232d, respectively, is desired by the MFCs 241c and 241d. After being controlled to have a flow rate, they are introduced into the processing chamber 201 from the nozzles 230a and 230b through the inert gas supply pipes 232c and 232d and the processing gas supply pipes 232a and 232b.
The N2 gas is mixed with each of SiH2 Cl2 gas and N2 O gas in the processing gas supply pipes 232a and 232b. The concentration of the processing gas can be controlled by controlling the supply flow rate of the N2 gas.

The processing gas introduced into the processing chamber 201 ascends in the processing chamber 201, flows out from the upper end opening of the inner tube 204 into the cylindrical space 250, flows down through the cylindrical space 250, and is exhausted from the exhaust pipe 231. The
The processing gas comes into contact with the surface of the wafer 200 when passing through the processing chamber 201. At this time, a thin film, that is, a silicon oxide (SiO2) film is deposited (deposited) on the surface of the wafer 200 by a thermal CVD reaction.

When a preset processing time has elapsed, the supply of the processing gas is stopped. That is, when the valves 262a, 261a, 262b, and 261b are closed, the supply of SiH2 Cl2 gas and N2 O gas from the SiH2 Cl2 gas supply source 271 and the N2 O gas supply source 272 into the processing chamber 201 is stopped. .
Thereafter, the valves 262c, 261c, 262d, and 261d are opened, and the inside of the processing chamber 201 is purged by exhausting from the exhaust pipe 231 while N2 gas is being supplied from the N2 gas supply source 273 into the processing chamber 201, The inside of the processing chamber 201 is replaced with N2 gas, and the pressure in the processing chamber 201 is returned to normal pressure.

  Thereafter, the seal cap 219 is lowered by the boat elevator 115 to open the lower end of the manifold 209, and the processed wafer 200 is unloaded from the lower end of the manifold 209 to the outside of the process tube 203 while being held by the boat 217. (Boat unload). Thereafter, the processed wafer 200 is taken out from the boat 217 (wafer discharge).

As a processing condition when processing the wafer 200 in the processing furnace 202 of the present embodiment, for example, in forming a silicon oxide film,
Process temperature: 700-830 degreeC,
Processing pressure: 10 to 100 Pa,
SiH2 Cl2 gas supply flow rate: 50 to 300 sccm,
N2 O gas supply flow rate: 50 to 600 sccm
The wafer 200 is processed by keeping each processing condition constant at a certain value within each range.

Next, a structure obtained by adding a protective structure for the rotating shaft to the above substrate processing apparatus will be described.
In a state where the boat 217 holding the wafers 200 is loaded into the processing furnace 202 (boat loading), the rotation shaft 255 and the gas supply nozzles 230a and 230b are at the same height, and between the boat 217 and the inner tube 204. Since the clearance is narrow and the nozzle shape is limited, when the gas is supplied, a large amount of gas flows fluidly and diffusively to the rotating shaft 255. Then, there is a concern about the corrosive influence of the metal on the rotating shaft 255 by the SiH2 Cl2 gas 281 which is a corrosive gas.
Therefore, as shown in FIG. 2 and FIG. 3, a corrosive SiH 2 Cl 2 gas 281 is provided by covering the rotating shaft 255 around the rotating shaft 255 with a shaft protector 301 as a cover member. And the flow of non-corrosive N2 O gas 282 are branched.
That is, the shaft protector 301 is made of quartz or silicon carbide (SiC) and is integrally formed in a short cylindrical shape having an open lower end surface as shown in FIG. An opening 302 is formed in a part of the upper end closing wall, and an escape hole 303 is formed in the upper end blocking wall for escaping the mounting portion 255a of the rotating shaft 255. The shaft protector 301 is placed on the seal cap receiver 304 placed on the seal cap 219 so as to cover the rotating shaft 255 (see FIGS. 2 and 3), and is laid down on the upper surface of the seal cap receiver 304. Positioning is performed by the positioning hole 305. By positioning the shaft protector 301, it is possible to prevent the shaft protector 301 and the rotating shaft 255 from contacting each other.
In addition, the shaft protector 301 is locked to the seal cap receiver 304 by engaging the rotation stop 306 projecting from the positioning hole 305 with the opening 302.
In the positioned state, as shown in FIGS. 3 and 4 (a), the opening 302 of the shaft protector 301 faces the nozzle 230b for supplying the non-corrosive N2 O gas 282. The nozzle 230a that supplies the reactive SiH2 Cl2 gas 281 is removed.

As described above, by installing the shaft protector 301 having the opening 302 in the side wall on the seal cap 219 so as to cover the rotating shaft 255, the SiH2 Cl2 gas 281 is formed as shown in FIG. Flows outside the shaft protector 301, so that the amount of SiH2 Cl2 gas flowing into the rotating shaft 255 can be reduced, and the N2 O gas 282 enters the shaft protector 301 from the opening 302 on the side of the shaft protector 301. Since it flows in, the purge effect around the rotating shaft 255 can be enhanced.
Thereby, corrosion of the metal part of the rotating shaft 255 can be prevented, and the level of metal contamination on the wafer 200 can be reduced.

  Needless to say, the present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the scope of the invention.

For example, the shaft protector as the cover member is not limited to being formed integrally, but may be formed in a split type. The split-type shaft protector can facilitate installation work on the seal cap.
In this case, like the split type shaft protector 301A shown in FIG. 4B, it is preferable to divide vertically so as to sandwich and cover the rotating shaft from the lateral direction of the rotating shaft. The vertically divided type shaft protector 301A can further facilitate the installation work on the seal cap.

  The shaft protector is not limited to be positioned by a positioning hole submerged in the seal cap receiver, but is positioned by a stopper 307 provided on the seal cap receiver or the seal cap, as indicated by an imaginary line in FIG. You may comprise.

  It is preferable to provide a baffle plate or the like in the shaft protector. By providing a baffle plate or the like, when N2 O gas is allowed to flow into the shaft protector, the gas can be temporarily stagnated, thereby promoting the decomposition of the reaction gas.

Preferred embodiments of the present invention will be additionally described.
According to one aspect of the present invention, a processing chamber for processing a substrate, a support for supporting the substrate in the processing chamber, a rotating shaft for supporting and rotating the support, and a corrosive gas in the processing chamber. A corrosive gas supply nozzle for supplying, a non-corrosive gas supply nozzle for supplying a non-corrosive gas into the processing chamber, a gas outlet of the corrosive gas supply nozzle, and a gas outlet of the non-corrosive gas supply nozzle And a cover member provided so as to cover the rotating shaft while facing the gas outlet, and having an opening provided in a portion facing the gas ejection port of the non-corrosive gas supply nozzle.
Preferably, the cover member is an integral type constituted by one member.
Preferably, the cover member is a split type constituted by a plurality of members.
Preferably, the cover member includes a plurality of members, and the plurality of members are configured to sandwich and cover the rotation shaft from a lateral direction of the rotation shaft.
Preferably, at least one baffle plate that prevents the flow of the non-corrosive gas and temporarily stagnates the non-corrosive gas is provided inside the cover member.
Preferably, the corrosive gas is SiH2 Cl2 gas and the non-corrosive gas is N2 O gas.
Preferably, the corrosive gas is SiH2 Cl2 gas and the non-corrosive gas is NH3 gas.

It is a longitudinal cross-sectional view which shows the reaction furnace of the substrate processing apparatus which is one Embodiment of this invention. It is a longitudinal cross-sectional view which shows a furnace port part detail. It is a cross-sectional view which shows a furnace port part detail. It is each perspective view which shows a shaft protector, (a) shows an integral-type shaft protector, (b) has shown the split-type shaft holder.

Explanation of symbols

200 wafer (substrate)
202 Processing furnace 203 Process tube 217 Boat 219 Seal cap 230a, 230b Nozzle 281 SiH2 Cl2 gas (corrosive gas)
282 N2 O gas (non-corrosive gas)
301 Shaft protector (cover member)
302 Opening 303 Relief hole 304 Seal cap receptacle 305 Positioning hole.

Claims (1)

A processing chamber for processing the substrate;
A support for supporting the substrate in the processing chamber;
A rotating shaft that supports and rotates the support;
A corrosive gas supply nozzle for supplying a corrosive gas into the processing chamber;
A non-corrosive gas supply nozzle for supplying a non-corrosive gas into the processing chamber;
The rotating shaft is provided so as to cover the gas outlet of the corrosive gas supply nozzle and the gas outlet of the non-corrosive gas supply nozzle, and faces the gas outlet of the non-corrosive gas supply nozzle. A cover member provided with an opening in a portion;
A substrate processing apparatus comprising:

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