JP2011171657A - Substrate treatment device and method for manufacturing semiconductor device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a substrate treatment device for reducing a consumption amount of cooling water, and a method for manufacturing a semiconductor device. <P>SOLUTION: A treatment furnace 202 for carrying out heat treatment to a wafer 200 is provided with a cooling water supply device 1 including a cooling water supply pump 2, an inlet cock 3, a pressure gauge 4, a cooling water line 5A of a manifold 209, a cooling water line 5B of a seal cap 219, a cooling water line 5C of a shutter 102, a cooling water line 5D of a jacket 207, flow rate adjusting valves 6A, 6B, 6C and 6D connected to the cooling water lines 5A to 5D, respectively, an outlet cock 7, a tank 8, and a flow rate control part 9. The manifold 209, the seal cap 219, the shutter 102, and the jacket 207 as cooling requirement parts are installed with thermo-couples 10A, 10B, 10C and 10D, respectively. The flow rate control part 9 controls the flow rate of cooling water by the respective flow rate adjusting valves 6A, 6B, 6C and 6D so that the measurement temperatures of the respective thermo-couples 10A, 10B, 10C and 10D can be kept constant. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a semiconductor manufacturing technique, and more particularly to a heat treatment technique in which a substrate to be processed is accommodated in a processing chamber and processed in a state of being heated by a heater. The present invention relates to a wafer (hereinafter referred to as a wafer) that is effective for oxidation treatment, diffusion treatment, carrier activation after ion implantation, reflow for planarization, annealing, and film formation treatment by thermal CVD reaction.

In an IC manufacturing method, a vertical thermal CVD apparatus may be used for a film forming process for forming a film on a wafer.
Generally, a vertical thermal CVD apparatus includes a process tube in which a processing chamber for accommodating a plurality of wafers and collectively processing, a heater installed outside the process tube for heating the processing chamber, and a processing chamber. A supply pipe for supplying a processing gas; and a boat for holding a plurality of wafers into a processing chamber, and holding the plurality of wafers in the processing chamber and carrying them into the processing chamber. A plurality of wafers are collectively processed by heating with a heater and supplying a processing gas into the processing chamber through a supply pipe.
In a conventional vertical thermal CVD apparatus, in order to protect members around the heater (for example, a seal member) or prevent excessive heat transfer to the outside of the apparatus, cooling water is allowed to flow to places where cooling is necessary. For example, see Patent Document 1.

JP 2009-1111025 A

  However, the flow rate of the cooling water is set to a constant flow rate that does not damage the device even when the heater is used at the maximum temperature and has a margin that prevents excessive heat transfer outside the device. Therefore, in the film forming process where a wide variety of process conditions exist, there are cases where the heater temperature actually used is low and there is no problem even if it is used at a lower flow rate than the constant set coolant flow rate. is doing. This means that cooling water is consumed more than necessary, leading to an increase in utility cost.

  The objective of this invention is providing the manufacturing method of the substrate processing apparatus which can reduce the consumption of a cooling water, and a semiconductor device.

According to one aspect of the present invention, the following substrate processing apparatus is provided.
A processing furnace for heating and processing the substrate;
A cooling water line for flowing cooling water to a place where cooling is required in the processing furnace;
A flow rate adjusting valve for adjusting a flow rate of cooling water provided in the cooling water line;
A temperature sensor that measures the temperature of the cooling-required portion;
A flow rate control unit for controlling the flow rate of the cooling water by controlling the flow rate adjustment valve based on temperature information measured by the temperature sensor;
A substrate processing apparatus comprising:
According to another aspect of the present invention, the following method for manufacturing a semiconductor device is provided.
Carrying the substrate into the processing furnace;
Heating and processing the substrate in the processing furnace;
Unloading the processed substrate from the processing furnace,
In each step, cooling water is allowed to flow from the cooling water line to the cooling-necessary part while measuring the temperature of the cooling furnace-necessary part with a temperature sensor, and the temperature is measured based on the temperature information measured by the temperature sensor. Controlling the flow rate of the cooling water by controlling a flow rate adjusting valve provided in the cooling water line;
A method for manufacturing a semiconductor device.

  According to the above means, the consumption of cooling water can be reduced.

It is front sectional drawing which shows the substrate processing apparatus which is one Embodiment of this invention. It is a circuit diagram which shows a cooling water supply apparatus. It is a circuit diagram which shows the cooling water flow control system.

  Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

  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 (SiO ₂ ) or silicon carbide (SiC), and is formed in a cylindrical shape having upper and lower ends opened. A processing chamber 201 is formed in the cylindrical hollow portion of the inner tube 204, and is configured so that wafers 200 as substrates can be accommodated in a state of being aligned in multiple stages in a horizontal posture and in a vertical direction by a boat 217 described later. The outer tube 205 is made of a heat-resistant material such as quartz or silicon carbide, and is formed in a cylindrical shape having an inner diameter larger than the outer diameter of the inner tube 204 and closed at the upper end and opened at the lower end. It is provided in the shape.

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.

  A nozzle 230 as a gas introduction unit is connected to a seal cap 219 described later so as to communicate with the inside of the processing chamber 201, and a gas supply pipe 232 is connected to the nozzle 230. A processing gas supply source and an inert gas supply source (not shown) are connected to an upstream side of the gas supply pipe 232 opposite to the connection side with the nozzle 230 via an MFC (mass flow controller) 241 as a gas flow rate controller. Has been. A gas flow rate control unit 235 is electrically connected to the MFC 241 and is configured to control at a desired timing so that the flow rate of the supplied gas becomes a desired amount.

  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 vacuum exhaust device 246 such as a vacuum pump is connected to the downstream side of the exhaust pipe 231 opposite to the connection side with the manifold 209 via a pressure sensor 245 and a pressure adjustment device 242 as a pressure detector. The chamber 201 is configured to be evacuated so that the pressure in the chamber 201 becomes a predetermined pressure (degree of vacuum). A pressure control unit 236 is electrically connected to the pressure adjustment device 242 and the pressure sensor 245, and the pressure control unit 236 is installed in the processing chamber 201 by the pressure adjustment device 242 based on the pressure detected by the pressure sensor 245. Control is performed at a desired timing so that the pressure becomes a desired pressure.

Below the manifold 209, a seal cap 219 is provided as a first furnace port lid capable of airtightly closing 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.
The seal cap 219 is provided with a rotating mechanism 254 that rotates the boat on the opposite side of 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 vertically lifted 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. It is possible. A drive control unit 237 is electrically connected to the rotation mechanism 254 and the boat elevator 115, and is configured to control at a desired timing so as to perform a desired operation.
Below the manifold 209, a shutter 102 is provided as a second furnace port lid that can airtightly close the lower end opening of the manifold 209. The shutter 102 seals the lower end opening of the manifold 209 in a state where the boat 217 is unloaded from the processing chamber 201. The shutter 102 is made of the same material as the seal cap 219 and is formed in a disk shape. On the upper surface of the shutter 102, an O-ring 103 is provided as a seal member that contacts the lower end of the manifold 209.

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 control unit 238 is electrically connected to the heater 206 and the temperature sensor 263, and by adjusting the power supply to the heater 206 based on the temperature information detected by the temperature sensor 263, Control is performed at a desired timing so that the temperature has a desired temperature distribution.

  The gas 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 a main control unit 239 that controls the entire substrate processing apparatus. ing. These gas 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 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.

  As shown in FIG. 1, when a plurality of wafers 200 are loaded into the boat 217 with the lower end opening of the manifold 209 sealed by the shutter 102 (wafer charging), the shutter 102 is opened, and the manifold The lower end opening 209 is opened, and 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.

Next, the processing chamber 201 is evacuated by the evacuation device 246 so as to have a desired pressure (degree of vacuum). At this time, the pressure in the processing chamber 201 is measured by the pressure sensor 245, and the pressure regulator 242 is feedback-controlled based on the measured pressure.
In addition, 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 inside of the processing chamber 201 has a desired temperature distribution.
Subsequently, the wafer 200 is rotated by rotating the boat 217 by the rotation mechanism 254.

Next, the gas supplied from the processing gas supply source and controlled to have a desired flow rate by the MFC 241 is introduced into the processing chamber 201 from the nozzle 230 through the gas supply pipe 232. The introduced gas rises in the processing chamber 201, flows out from the upper end opening of the inner tube 204 into the cylindrical space 250, and is exhausted from the exhaust pipe 231.
The gas comes into contact with the surface of the wafer 200 when passing through the processing chamber 201, and at this time, a thin film is deposited on the surface of the wafer 200 by a thermal CVD reaction.

  When a preset processing time has passed, an inert gas is supplied from an inert gas supply source, the inside of the processing chamber 201 is replaced with an inert 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, the lower end of the manifold 209 is opened, and the processed wafer 200 is held by the boat 217 to the outside of the process tube 203 from the lower end of the manifold 209. Unload (boat unloading). Thereafter, the lower end of the manifold 209 is sealed by the shutter 102, and the processed wafer 200 is taken out from the boat 217 (wafer discharge).

  In the processing furnace 202 described above, in order to protect the members around the heater 206 and prevent excessive heat transfer to the outside of the processing furnace 202, the cooling water supply device shown in FIG. 1 is flowing.

Locations that require cooling will be described with reference to FIGS.
In the film forming process, the wafer 200 may be processed by flowing a toxic gas or a combustible gas into the processing chamber 201. It is necessary to prevent these gases from flowing from the processing chamber 201 into the transfer chamber 101 (see FIG. 1). Further, the inside of the processing chamber 201 may be decompressed. For these reasons, an O-ring 220a is provided between the manifold 209 and the outer tube 205, and an O-ring 220b is provided between the upper surface of the seal cap 219 and the lower surface of the manifold 209. In order to prevent these O-rings 220 a and 220 b from being melted or deteriorated due to heat conduction from the heater 206, cooling water is allowed to flow in the manifold 209 and the seal cap 219.
Similarly, as shown in FIG. 1, the O-ring 103 is also provided on the shutter 102 that closes the lower end opening of the manifold 209 in the state where the boat 217 is carried out from the processing chamber 201, so that the cooling water is not supplied. Being washed away.
In order to prevent heat from escaping to the outside of the processing furnace 202, a heater cooling jacket (hereinafter referred to as a jacket) 207 is wound around the heater 206, and cooling water is also supplied to the jacket 207.

As shown in FIG. 2, the cooling water supply device 1 according to this embodiment includes a cooling water supply pump 2, an inlet cock 3, a pressure gauge 4, a cooling water line 5 </ b> A of a manifold 209, and a cooling water of a seal cap 219. Line 5B, cooling water line 5C of shutter 102, cooling water line 5D of jacket 207, flow rate adjusting valves 6A, 6B, 6C and 6D connected to each of cooling water lines 5A to 5D, outlet cock 7, tank 8 and flow rate. A control unit 9 is provided.
Thermocouples 10A, 10B, 10C, and 10D as temperature sensors are installed on the manifold 209, the seal cap 219, the shutter 102, and the jacket 207, respectively, as places where cooling is required. The flow rate control unit 9 controls the flow rate of the cooling water using the flow rate adjusting valves 6A, 6B, 6C, and 6D so that the measured temperatures of the thermocouples 10A, 10B, 10C, and 10D are kept constant. Reduce consumption.

Hereinafter, the operation of the cooling water supply apparatus 1 will be described with reference to FIGS. 2 and 3 by taking the cooling water flow rate control of the seal cap 219 as an example.
The cooling water of the seal cap 219 flows for the purpose of protecting the O-ring 220b. When the heat-resistant temperature of the O-ring 220b is 180 ° C., the flow rate control unit 9 is set so that the temperature of the thermocouple 10B becomes 160 ° C., for example. Set the target temperature to.
As shown in FIG. 3, the flow rate control unit 9 takes in the value of the thermocouple 10B in the immediate vicinity of the O-ring 220b, calculates the PID for the deviation of the target temperature, and outputs it to the flow rate adjustment valve 6B.

Next, the relationship between the actual processing sequence of the wafer 200 and the cooling water flow rate will be described.
Before the wafer 200 is processed, the seal cap 219 is in the transfer chamber 101, so there is no heat conduction from the heater 206, and the value of the thermocouple 10B in the immediate vicinity of the O-ring 220b is a value close to room temperature. Accordingly, at this time, the flow rate control unit 9 outputs to go to close the flow rate control valve 6B.
In actual operation, if the flow rate adjustment valve 6B is fully closed, the flow in the cooling water line 5B disappears, and the temperature of the thermocouple 10B may rise rapidly when heat is applied. It is better to keep the minimum flow rate.
In addition, when the flow rate adjustment valve 6B is fully closed, micro bubbles are generated in the vicinity of the flow rate adjustment valve 6B, and there is a phenomenon that water hardly flows when the flow rate adjustment valve 6B is opened next time. In order to avoid this, it is preferable to keep the opening degree of the flow regulating valve 6B to the minimum necessary.

After the wafer 200 is transferred to the boat 217 on the seal cap 219, when the seal cap 219 rises to a position where the wafer 200 is formed, the temperature near the O-ring 220b starts to rise due to heat conduction from the heater 206. The flow rate control unit 9 adjusts the output to the flow rate adjustment valve 6B so that the target value (for example, 160 ° C.) of the thermocouple 10B closest to the O-ring 220b is the same value (open the flow rate adjustment valve 6B). Will go).
After the film formation is completed, the seal cap 219 is lowered after the temperature of the heater 206 and the wafer 200 is lowered, and the wafer 200 is discharged from the boat 217 (discharge). However, even if the heat conduction from the heater 206 is lost, the value of the thermocouple 10B gradually decreases because the seal cap 219 itself has a certain heat capacity.
Therefore, the flow rate control unit 9 also changes the command to the flow rate adjustment valve 6B in the direction from open to close as the temperature of the thermocouple 10B decreases.

  As described above, in the present embodiment, when heat is applied to a portion requiring cooling, the flow rate of the cooling water is automatically flowed as a large flow rate, and when the temperature of the cooling point is lowered, the flow rate of the cooling water Automatically reduces the consumption of cooling water.

Other cooling-necessary portions will be described.
Since the shutter 102 covers the lower end opening of the manifold 209 when the seal cap 219 is fully lowered, the shutter 102 is in a state where the seal cap 219 is moving up or down or when the seal cap 219 is at the film forming position. Does not conduct heat from the heater 206.
Accordingly, the cooling water flow rate of the cooling water line 5C of the shutter 102 is set such that the cooling water flow rate is large when the shutter 102 covers the lower end opening of the manifold 209, and otherwise the cooling water flow rate is small. The consumption of cooling water can be reduced.

  In addition, the temperature of the heater 206 at the time of standby of the substrate processing apparatus (preparation state or standby state of the substrate processing apparatus, that is, when film formation processing is not performed) is lower than the temperature of the heater 206 during film formation. The temperatures of the manifold 209 and the jacket 207 are also lowered, and the cooling water flow rate during standby can also be reduced for the cooling water line 5A of the manifold 209 and the cooling water line 5D of the jacket 207.

  According to the above embodiment, the following effects can be obtained.

(1) The consumption of cooling water used in the processing furnace can be reduced. Although there are parts that depend on the configuration of the processing furnace and the processing recipe, a reduction of about 25% of the amount of cooling water used in the conventional processing furnace is expected in the calculation.

(2) When the processing temperature was changed, if it was a conventional processing furnace, when changing the flow rate setting value of the cooling water, it was necessary to measure the temperature of the cooling location, and work man-hours were generated. However, in the present embodiment, since the flow rate of the cooling water is automatically controlled according to the temperature of the cooling location, no extra work man-hours are generated.

  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, a temperature sensor such as a thermocouple provided at a place where cooling is required may not be able to measure the temperature accurately. It is preferable to be configured so that it can be measured.

  In addition, when the temperature of the cooling water is 60 ° C. or higher, depending on the water quality, foreign matter may be deposited in the cooling water line and clogging may occur in the piping. It is preferable to measure the cooling water temperature.

  When the temperature of the cooling water rises abnormally, it is preferable to configure a fail-safe system that forcibly opens the flow rate adjustment valve.

  In the said embodiment, although the vertical thermal CVD apparatus provided with the process tube which consists of an outer tube and an inner tube was demonstrated, this invention is not restricted to this, The other CVD apparatus provided with the process tube only of an outer tube In addition, the present invention can be applied to substrate processing apparatuses such as diffusion apparatuses and oxidation apparatuses and semiconductor device manufacturing methods using them.

DESCRIPTION OF SYMBOLS 1 ... Cooling water supply apparatus 2 ... Cooling water supply pump 3 ... Inlet cock 4 ... Pressure gauge 5A ... Cooling water line 5B of manifold 209 ... Cooling water line 5C of seal cap 219 ... Cooling water line 5D of shutter 102 ... Jacket 207 Cooling water lines 6A, 6B, 6C, 6D ... Flow rate adjusting valve 7 ... Outlet cock 8 ... Tank 9 ... Flow rate control units 10A, 10B, 10C, 10D ... Thermocouple (temperature sensor)

Claims (2)

A processing furnace for heating and processing the substrate;
A cooling water line for flowing cooling water to a place where cooling is required in the processing furnace;
A flow rate adjusting valve for adjusting a flow rate of cooling water provided in the cooling water line;
A temperature sensor that measures the temperature of the cooling-required portion;
A flow rate control unit for controlling the flow rate of the cooling water by controlling the flow rate adjustment valve based on temperature information measured by the temperature sensor;
A substrate processing apparatus comprising: Carrying the substrate into the processing furnace;
Heating and processing the substrate in the processing furnace;
Unloading the processed substrate from the processing furnace,
In each step, cooling water is allowed to flow from the cooling water line to the cooling-necessary part while measuring the temperature of the cooling furnace-necessary part with a temperature sensor, and the temperature is measured based on the temperature information measured by the temperature sensor. Controlling the flow rate of the cooling water by controlling a flow rate adjusting valve provided in the cooling water line;
A method for manufacturing a semiconductor device.

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