Patent Application
20190127848
The present disclosure relates to a processing method, a method of manufacturing a semiconductor device and a non-transitory computer-readable recording medium.
When a film-forming process is performed for forming a deposition film on a substrate in a process chamber of a substrate processing apparatus, deposits (that is, deposited materials) such as a film and by-products (hereinafter, also referred to as “reaction by-products”) are deposited not only on the substrate but also in other regions in the process chamber. As a method of removing the deposits, a cleaning gas is supplied into the process chamber to remove the deposits. For example, hydrogen fluoride (HF) gas may be used as the cleaning gas.
However, the etching rate may be different between one end of the process chamber and the other end of the process chamber. Therefore, the deposits such as the reaction by-products are liable to remain in locations wherefrom it is difficult to remove the deposits due to the variation in the etching rate. In order to remove the deposits such as the reaction by-products remaining in such locations as above, it is necessary to supply the cleaning gas for a longer time. In addition, if the cleaning by the cleaning gas is not sufficient to remove the deposits, the deposits must be removed manually by, for example, wiping the deposits. As a result, the time required for cleaning the deposits is prolonged.
Described herein is a technique capable of shortening the time required for performing the cleaning process while suppressing the variation of the etching rate depending on the location in the cleaning region.
According to one aspect of the technique described herein, there is provided a processing method including: (a) processing a substrate accommodated in a substrate holding region of a substrate retainer in a process chamber at a first temperature, the substrate retainer including a heat insulating region on one end thereof and the substrate holding region on the other end thereof; (b) supplying a cleaning gas to the heat insulating region at a second temperature variable within a temperature range lower than the first temperature and higher than a room temperature after unloading the substrate accommodated in the substrate retainer; and (c) supplying the cleaning gas to the substrate holding region at a third temperature variable within another temperature range lower than the second temperature after unloading the substrate accommodated in the substrate retainer.
Hereinafter, one or more embodiments according to the technique will be described with reference to
A reaction tube 16 is provided in the heater 14 so as to be concentric with the heater 14. The reaction tube 16 is cylindrical with a closed upper end and an open lower end. The reaction tube 16 is made of a heat resistant material such as quartz (SiO2) and silicon carbide (SiC).
An inlet flange (hereinafter, also referred to as an “inlet” or a “manifold”) 18 is provided under the reaction tube 16 so as to be concentric with the reaction tube 16. The inlet 18 is cylindrical with open upper and lower ends. The inlet 18 is made of a metal such as stainless steel (SUS). An upper end portion of the inlet 18 is engaged with the lower end of the reaction tube 16 so as to support the reaction tube 16.
An O-ring 20a serving as a sealing part is provided between the inlet 18 and the reaction tube 16. The reaction tube 16 is vertically installed by the inlet 18 being supported by the heater base.
A process vessel (reaction vessel) is constituted mainly by the reaction tube 16 and the inlet 18. A process chamber 22 is provided in a hollow cylindrical portion of the process vessel. An opening portion for loading wafers 24 serving as substrates into the process chamber 22 and for unloading the wafers 24 out of the process chamber 22 is provided under the process chamber 22. The process chamber 22 is configured to accommodate the vertically arranged wafers 24 in a horizontal orientation in a multistage manner by a boat 28 serving as a substrate retainer capable of accommodating the wafers 24. Hereinafter, the wafers 24 may also be referred to as the substrates 24.
The boat 28 aligns the substrates 24 in the vertical direction and supports the substrates 24, while the substrates 24 are horizontally oriented with their centers aligned with each other. The boat 28 is made of a heat resistant material such as quartz and SiC. A heat insulating part 30 is provided under the boat 28. The heat insulating part 30 may be constituted by a plurality of heat insulating plates (not shown) made of a heat resistant material such as quartz and SiC and a heat insulating plate holder for supporting the plurality of heat insulating plates in a horizontal orientation in a multistage manner.
The process furnace 12 is provided with a first gas supply system (hereinafter, also referred to as a “source gas supply system”) 32, a second gas supply system (hereinafter, also referred to as a “reactive gas supply system”) 34 and a third gas supply system (hereinafter, also referred to as a “cleaning gas supply system”) 36. The first gas supply system 32 is configured to supply a first gas (for example, a source gas) for processing the substrates 24 into the process chamber 22. The second gas supply system 34 is configured to supply a second gas (for example, a reactive gas) for processing the substrates 24 into the process chamber 22. The third gas supply system 36 is configured to supply a third gas (for example, a cleaning gas) for cleaning an inside of the process chamber 22 into the process chamber 22.
The process furnace 12 is provided with nozzles 40a, 40b and 40c configured to supply various gases into the process chamber 22. The nozzles 40a, 40b and 40c are provided in the process chamber 22 through a sidewall of the inlet 18. The nozzles 40a, 40b and 40c are made of a heat resistant material such as quartz and SiC. A gas supply pipe 42a and an inert gas supply pipe 52a are connected to the nozzle 40a. A gas supply pipe 42b and an inert gas supply pipe 52b are connected to the nozzle 40b. A gas supply pipe 42c, an inert gas supply pipe 52c, a cleaning gas supply pipe 62a, a gas supply pipe 42d and an inert gas supply pipe 52d are connected to the nozzle 40c.
A mass flow controller (MFC) 44a serving as a flow rate controller (flow rate control mechanism) and a valve 46a serving as an opening/closing valve are sequentially provided at the gas supply pipe 42a from the upstream side toward the downstream side of the gas supply pipe 42a. The inert gas supply pipe 52a is connected to the gas supply pipe 42a at the downstream side of the valve 46a. The nozzle 40a is connected to a front end of the gas supply pipe 42a. An MFC 54a and a valve 56a are sequentially provided at the inert gas supply pipe 52a from the upstream side toward the downstream side of the inert gas supply pipe 52a.
The nozzle 40a is provided in an annular space between an inner wall of the reaction tube 16 and the substrates 24 accommodated in the process chamber 22, and extends from the inlet 18 to an inside of the reaction tube 16 along a stacking direction of the substrates 24. The nozzle 40a is provided in a region that horizontally surrounds a wafer holding region (hereinafter, also referred to as a “substrate holding region”) at one side of the wafer holding region where the substrates 24 are accommodated along the wafer holding region.
A plurality of gas supply holes 48a is provided at a side surface of the nozzle 40a. The plurality of gas supply holes 48a is open toward the center of the reaction tube 16. The plurality of gas supply holes 48a is configured to supply the gas such as a source gas toward the substrates 24 accommodated in the process chamber 22. The plurality of gas supply holes 48a is provided from a lower portion of the wafer holding region in the reaction tube 16 to an upper portion thereof.
The first gas supply system 32 is constituted mainly by the gas supply pipe 42a, the MFC 44a and the valve 46a. A first inert gas supply system is constituted mainly by the inert gas supply pipe 52a, the MFC 54a and the valve 56a.
The source gas containing a predetermined element and a halogen element is supplied through the gas supply pipe 42a. For example, a chlorosilane-based source gas serving as the source gas containing silicon (Si) as the predetermined element and chlorine (Cl) as the halogen element is supplied into the process chamber 22 via the MFC 44a and the valve 46a provided at the gas supply pipe 42a and the nozzle 40a. For example, hexachlorodisilane (Si2Cl6, abbreviated as HCDS) gas may be used as the chlorosilane-based source gas.
The source gas refers to a source which remains in gaseous state under normal temperature and pressure or a gas obtained by vaporizing a liquid source under normal temperature and pressure. The chlorosilane-based source refers to a silane-based source containing chloro group as a halogen group, that is, a source containing at least silicon (Si) and chlorine (Cl).
An MFC 44c and a valve 46c are sequentially provided at the gas supply pipe 42c from the upstream side toward the downstream side of the gas supply pipe 42c. The inert gas supply pipe 52c is connected to the gas supply pipe 42c at the downstream side of the valve 46c. An MFC 54c and a valve 56c are sequentially provided at the inert gas supply pipe 52c from the upstream side toward the downstream side of the inert gas supply pipe 52c.
The nozzle 40c is provided in the annular space and extends from a lower portion of the reaction tube 16 to an upper portion thereof. The nozzle 40c is provided in the region that horizontally surrounds the wafer holding region at one side of the wafer holding region where the substrates 24 are accommodated along the wafer holding region.
A plurality of gas supply holes 48c is provided at a side surface of the nozzle 40c. The plurality of gas supply holes 48c is open toward the center of the reaction tube 16. The plurality of gas supply holes 48c is configured to supply the gas such as the reactive gas toward the substrates 24 accommodated in the process chamber 22. The plurality of gas supply holes 48c is provided from the lower portion of the wafer holding region in the reaction tube 16 to the upper portion thereof.
The gas supply pipe 42d is connected to the gas supply pipe 42c at the downstream sides of the valve 46c provided at the gas supply pipe 42c and the valve 56c provided at the inert gas supply pipe 52c. An MFC 44d and a valve 46d are sequentially provided at the gas supply pipe 42d from the upstream side toward the downstream side of the gas supply pipe 42d. The inert gas supply pipe 52d is connected to the gas supply pipe 42d at the downstream side of the valve 46d. An MFC 54d and a valve 56d are sequentially provided at the inert gas supply pipe 52d from the upstream side toward the downstream side of the inert gas supply pipe 52d.
The second gas supply system 34 is constituted mainly by the nozzle 40c, the gas supply pipes 42c and 42d, the MFCs 44c and 44d and the valves 46c and 46d. A second inert gas supply system is constituted mainly by the inert gas supply pipes 52c and 52d, the MFCs 54c and 54d and the valves 56c and 56d.
The reactive gas such as an oxygen (O)-containing gas is supplied through the gas supply pipe 42c. The oxygen-containing gas serves as an oxidation gas. For example, an oxygen gas (O2 gas) serving as the oxygen-containing gas is supplied into the process chamber 22 via the MFC 44c and the valve 46c provided at the gas supply pipe 42c and the nozzle 40c. When the oxygen gas is supplied into the process chamber 22, an inert gas may be supplied into the gas supply pipe 42c via the MFC 54c and the valve 56c provided at the inert gas supply pipe 52c.
The reactive gas such as a hydrogen (H)-containing gas is supplied through the gas supply pipe 42d. The hydrogen-containing gas serves as a reducing gas. For example, a hydrogen gas (H2 gas) serving as the hydrogen-containing gas is supplied into the process chamber 22 via the MFC 44d and the valve 46d provided at the gas supply pipe 42d and the nozzle 40c. When the hydrogen gas is supplied into the process chamber 22, the inert gas may be supplied into the gas supply pipe 42d via the MFC 54d and the valve 56d provided at the inert gas supply pipe 52d.
The cleaning gas supply pipe 62a is connected to the gas supply pipe 42c. An MFC 64a and a valve 66a are sequentially provided at the cleaning gas supply pipe 62a from the upstream side toward the downstream side of the cleaning gas supply pipe 62a. An MFC 64b and a valve 66b are sequentially provided at the cleaning gas supply pipe 62b from the upstream side toward the downstream side of the cleaning gas supply pipe 62b. The inert gas supply pipe 52b is connected to the cleaning gas supply pipe 62b at the downstream side of the valve 66b. An MFC 54b and a valve 56b are sequentially provided at the inert gas supply pipe 52b from the upstream side toward the downstream side of the inert gas supply pipe 52b. Referring to
A gas supply hole 48b configured to supply the gas such as the cleaning gas is provided at a front end of the nozzle 40b. The gas supply hole 48b is open in the horizontal direction. More specifically, the gas supply hole 48b is open in the direction from an inner wall side of the inlet 18 toward an inside of the inlet 18. The nozzle 40b is configured to supply the gas such as the cleaning gas into the process chamber 22 such that the gas is supplied at a position closer to the inlet 18 than the nozzle 40c in a heat insulating region.
A first cleaning gas supply system is constituted mainly by the nozzle 40b, the cleaning gas supply pipe 62b, the MFC 64b and the valve 66b. A second cleaning gas supply system is constituted mainly by the nozzle 40c, the cleaning gas supply pipe 62a, the MFC 64a and the valve 66a. A third inert gas supply system is constituted mainly by the inert gas supply pipe 52b, the MFC 54b and the valve 56b. The third gas supply system 36 is constituted by the first cleaning gas supply system and the second cleaning gas supply system.
The cleaning gas such as a fluorine (F)-containing gas is supplied through the cleaning gas supply pipe 62a. For example, hydrogen fluoride (HF) gas serving as the fluorine-containing gas is supplied into the process chamber 22 via the MFC 64a and the valve 66a provided at the cleaning gas supply pipe 62a, the gas supply pipe 42c and the nozzle 40c. Specifically, the hydrogen fluoride gas is supplied mainly to the surfaces of the components (for example, the inner wall of the reaction tube 16 in the wafer holding region and the boat 28 accommodated in the process chamber 22). When the cleaning gas is supplied into the process chamber 22 through the cleaning gas supply pipe 62a, the inert gas may be supplied into the process chamber 22 through the inert gas supply pipes 52c and 52d. Specifically, the inert gas may be supplied into the process chamber 22 via the MFCs 54c and 54d and the valves 56c and 56d provided at the inert gas supply pipes 52c and 52d, the gas supply pipe 42c and the nozzle 40c. Compared to other kinds of cleaning gas, the hydrogen fluoride gas can remove oxide-based deposits at a lower temperature, for example, a temperature lower than 100° C.
Similarly, the cleaning gas such as the fluorine-containing gas is supplied through the cleaning gas supply pipe 62b. For example, the hydrogen fluoride (HF) gas serving as the fluorine-containing gas is supplied into the process chamber 22 via the MFC 64b and the valve 66b provided at the cleaning gas supply pipe 62b and the nozzle 40b. Specifically, the hydrogen fluoride gas is supplied mainly to the surfaces of the components (for example, the inner wall of the reaction tube 16, the inner wall side of the inlet 18 in the heat insulating region and the boat 28 accommodated in the process chamber 22). When the cleaning gas is supplied into the process chamber 22 through the cleaning gas supply pipe 62b, the inert gas may be supplied into the cleaning gas supply pipe 62b through the inert gas supply pipe 52b. Specifically, the inert gas may be supplied into the cleaning gas supply pipe 62b via the MFC 54b and the valve 56b provided at the inert gas supply pipe 52b.
The exhaust pipe 90 configured to exhaust an inner atmosphere of the process chamber 22 is provided at the reaction tube 16. A vacuum pump 96 serving as a vacuum exhauster is connected to the exhaust pipe 90 through a pressure sensor 92 and an APC (Automatic Pressure Controller) valve 94. The pressure sensor 92 serves as a pressure detector (pressure detection mechanism) to detect an inner pressure of the process chamber 22, and the APC valve 94 serves as a pressure controller (pressure adjusting mechanism). With the vacuum pump 96 in operation, the APC valve 94 may be opened/closed to vacuum-exhaust the process chamber 22 or stop the vacuum exhaust.
An exhaust system is constituted mainly by the exhaust pipe 90, the pressure sensor 92 and the APC valve 94. The exhaust system may further include the vacuum pump 96. With the vacuum pump 96 in operation, an opening degree of the APC valve 94 may be adjusted based on the pressure detected by the pressure sensor 92, in order to control the inner pressure of the process chamber 22 to a predetermined pressure (vacuum degree). Similar to the components such as the nozzle 40a and the nozzle 40b provided at the inlet 18, the exhaust pipe 90 may be provided at the inlet 18 instead of the reaction tube 16.
A seal cap 100 serving as a first furnace opening cover capable of airtightly sealing a lower end opening of the inlet 18, is provided under the inlet 18. The seal cap 100 is in contact with the lower end of the inlet 18 from thereunder. The seal cap 100 is made of a metal such as stainless steel, and is disk-shaped. An O-ring 20b serving as a sealing part is provided on an upper surface of the seal cap 100 so as to be in contact with the lower end of the inlet 18.
A rotating mechanism 102 configured to rotate the boat 28 is provided under the seal cap 100 opposite to the process chamber 22. A rotating shaft 104 of the rotating mechanism 102 is connected to the boat 28 through the seal cap 100. The rotating shaft 104 is made of a metal such as stainless steel. As the rotating mechanism 102 rotates the boat 28, the substrates 24 supported by the boat 28 are rotated.
A boat elevator 106 serving as an elevating mechanism is provided at the outside the reaction tube 16 vertically. The seal cap 100 may be moved upward/downward in the vertical direction by the boat elevator 106. When the seal cap 100 is moved upward/downward by the boat elevator 106, the boat 28 placed on the seal cap 100 may be loaded into the process chamber 22 or unloaded out of the process chamber 22. The boat elevator 106 serves as a transfer device (transfer mechanism) that loads the boat 28, that is, the substrates 24 accommodated in the boat 28 into the process chamber 22 or unloads the boat 28, that is, the substrates 24 accommodated in the boat 28 out of the process chamber 22.
A shutter 110 serving as a second furnace opening cover capable of airtightly sealing the lower end opening of the inlet 18, is provided under the inlet 18. The shutter 110 is made of a metal such as stainless steel, and is disk-shaped. An O-ring 20c serving as a sealing part is provided on an upper surface of the shutter 110 so as to be in contact with the lower end of the inlet 18. The shutter 110 is configured to close the lower end opening of the inlet 18 when the seal cap 100 is lowered to open the lower end opening of the inlet 18. The shutter 110 is configured to retract from the lower end opening of the inlet 18 when the seal cap 100 is elevated to close the lower end opening of the inlet 18. The opening/closing operation of the shutter 110 such as the elevation and the rotation is controlled by a shutter opening/closing mechanism 112 provided at the outside the reaction tube 16.
Referring to
A controller 200 serving as a control device (control mechanism) is constituted by a computer including a CPU (Central Processing Unit) 202, a RAM (Random Access Memory) 204, a memory device 206 and an I/O port 208. The RAM 204, the memory device 206 and the I/O port 208 may exchange data with the CPU 202 through an internal bus 210. For example, an input/output device 212 such as a touch panel is connected to the controller 200.
The memory device 206 is configured by components such as a flash memory and HDD (Hard Disk Drive). An operation program of the CPU 202 is readably stored in the memory device 206. For example, a control program for controlling the operation of the substrate processing apparatus 10, a process recipe containing information on the sequences and conditions of a substrate processing (film-forming process) described later or a cleaning recipe containing information on the sequences and conditions of a cleaning process) described later is readably stored in the memory device 206.
The process recipe is obtained by combining steps of the film-forming process (substrate processing) described later such that the controller 200 can execute the steps to acquire a predetermine result, and functions as a program. The cleaning recipe is obtained by combining steps of the cleaning process described later such that the controller 200 can execute the steps to acquire a predetermine result, and functions as a program. Hereafter, the process recipe, the cleaning recipe and the control program are collectively referred to as a “program”. In the present specification, “program” may indicate only the process recipe, indicate only the cleaning recipe, indicate only the control program, or indicate any combination of the process recipe, the cleaning recipe and/or the control program.
The RAM 204 is a memory area (work area) where a program or data read by the CPU 202 is temporarily stored.
The I/O port 208 is connected to the above-described components such as the mass flow controllers (MFCs) 44a, 44c, 44d, 54a, 54b, 54c, 54d, 64a and 64b, the valves 46a, 46c, 46d, 56a, 56b, 56c, 56d, 66a and 66b, the pressure sensor 92, the APC valve 94, the vacuum pump 96, the heater 14, the temperature sensor 114, the rotating mechanism 102, the boat elevator 106 and the shutter opening/closing mechanism 112.
The CPU 202 forms a backbone of the controller 200. The CPU 202 is configured to read a control program from the memory device 206 and execute the read control program. Furthermore, the CPU 202 is configured to read a recipe such as the process recipe and the cleaning recipe from the memory device 206 according to an operation command inputted from the input/output device 212. According to the contents of the read recipe, the CPU 202 may be configured to control various operations such as flow rate adjusting operations for various gases by the MFCs 44a, 44c, 44d, 54a, 54b, 54c, 54d, 64a and 64b, opening/closing operations of the valves 46a, 46c, 46d, 56a, 56b, 56c, 56d, 66a and 66b, an opening/closing operation of the APC valve 94, a pressure adjusting operation by the APC valve 94 based on the pressure sensor 92, a temperature adjusting operation of the heater 14 based on the temperature sensor 114, a start and stop of the vacuum pump 96, an operation of adjusting rotation and rotation speed of the boat 28 by the rotating mechanism 102, an elevating and lowering operation of the boat 28 by the boat elevator 106, and an opening/closing operation of the shutter 110 by the shutter opening/closing mechanism 112.
The controller 200 may be embodied by installing the above-described program stored in an external memory device 220 into a computer. For example, the external memory device 220 may include a magnetic disk such as a hard disk, an optical disk such as a CD, a magneto-optical disk such as MO, and a semiconductor memory such as a USB memory. The memory device 206 or the external memory device 220 may be embodied by a non-transitory computer readable recording medium. Hereafter, the memory device 206 and the external memory device 220 are collectively referred to as recording media. In the present specification, the term “recording media” may indicate only the memory device 206, indicate only the external memory device 220, and indicate both of the memory device 206 and the external memory device 220. Instead of the external memory device 220, a communication means such as the Internet and a dedicated line may be used for providing the program to the computer.
Hereinafter will be described an exemplary sequence of forming a film on the substrates 24 (that is, the substrate processing or the film-forming process) and cleaning the inside of the process chamber 22 (that is, the cleaning process) after the film-forming process is completed, which is a part of a manufacturing process of a semiconductor device. The exemplary sequence is performed by using the process furnace 12 of the above-described substrate processing apparatus 10. Hereinafter, the components of the substrate processing apparatus 10 are controlled by the controller 200.
Hereinafter, an example of forming a silicon oxide film (SiO2 film. Hereinafter, also referred to as a “SiO film”) by using the HCDS gas as the source gas and the O2 gas and the H2 gas as the reactive gas and cleaning the inside of the process chamber 22 by using the hydrogen fluoride (HF) gas as the cleaning gas after the SiO film is formed, will be described in detail with reference to
In the present specification, the term “wafer” may refer to “a wafer itself” or refer to “a wafer and a stacked structure (aggregated structure) of predetermined layers or films formed on the surface of the wafer”. In addition, “surface of a wafer” refers to “a surface (exposed surface) of a wafer itself” or “the surface of a predetermined layer or film formed on the wafer, i.e. the top surface of the wafer as a stacked structure”. Thus, in the present specification, “forming a predetermined layer (or film) on a wafer” may refer to “forming a predetermined layer (or film) on a surface of wafer itself” or refer to “forming a predetermined layer (or film) on a surface of a layer or a film formed on the wafer”. In the present specification, “substrate” and “wafer” may be used as substantially the same meaning. That is, the term “substrate” may be substituted by “wafer” and vice versa.
The substrates 24 are charged in the boat 28 (wafer charging step). After the boat 28 is charged with the substrates 24, the shutter 110 is moved by the shutter opening/closing mechanism 112 to open the lower end opening of the inlet 18. Then, the boat 28 charged with the substrates 24 is elevated by the boat elevator 106 and loaded into the process chamber 22 (boat loading step). With the boat 28 loaded, the seal cap 100 seals the lower end opening of the inlet 18 via the O-ring 20b.
The vacuum pump 96 vacuum-exhausts the process chamber 22 until the inner pressure of the process chamber 22 reaches a desired pressure (vacuum degree). In the pressure and temperature adjusting step, the inner pressure of the process chamber 22 is measured by the pressure sensor 92, and the APC valve 94 is feedback-controlled based on the measured pressure (pressure adjusting step). The vacuum pump 96 continuously vacuum-exhausts the process chamber 22 until at least the processing of the substrates 24 is completed. The heater 14 heats the process chamber 22 until the temperature of the substrates 24 in the process chamber 22 reaches a desired first temperature. The amount of the current flowing to the heater 14 is feedback-controlled based on the temperature detected by the temperature sensor 114 such that the inner temperature of the process chamber 22 has a desired temperature distribution (temperature adjusting step). The heater 14 continuously heats the process chamber 22 until at least the processing of the substrates 24 is completed. The rotating mechanism 102 rotates the boat 28. As the rotating mechanism 102 rotates the boat, the substrates 24 supported by the boat 28 are rotated. Until at least the processing of the substrates 24 is completed, the boat rotating mechanism 102 continuously rotates the boat 28 and the substrates 24.
Next, the SiO film having a predetermined thickness is formed on the substrates 24 by performing a cycle including a first step, a second step, a third step and a fourth step described below a predetermined number of times as shown
In the first step, a layer (silicon-containing layer) is formed on the substrates 24 by supplying the source gas such as the HCDS gas onto the substrates 24 accommodated in the process chamber 22.
First, the valve 46a is opened to supply the HCDS gas into the gas supply pipe 42a. The flow rate of the HCDS gas supplied into the gas supply pipe 42a is adjusted by the MFC 44a. The HCDS gas whose flow rate is adjusted is supplied onto the substrates 24 in the heated and depressurized process chamber 22 through the plurality of gas supply holes 48a of the nozzle 40a, and is exhausted through the exhaust pipe 90. As described above, the HCDS gas is supplied onto the substrates 24 (HCDS gas supplying step).
In the first step, the valve 56a may be opened to supply the inert gas such as N2 gas through the inert gas supply pipe 52a. After the flow rate of the N2 gas is adjusted by the MFC 54a, the N2 gas whose flow rate is adjusted is supplied into the gas supply pipe 42a. The N2 gas whose flow rate is adjusted is mixed with the HCDS gas whose flow rate is adjusted in the gas supply pipe 42a, then supplied onto the substrates 24 in the heated and depressurized process chamber 22 through the plurality of gas supply holes 48a of the nozzle 40a, and is exhausted through the exhaust pipe 90.
In order to prevent the HCDS gas from entering the nozzles 40b and 40c, the valves 56b, 56c and 56d are opened to supply the N2 gas into the inert gas supply pipes 52b, 52c and 52d. The N2 gas supplied into the inert gas supply pipes 52b, 52c and 52d is then supplied into the process chamber 22 through the cleaning gas supply pipe 62b, the gas supply pipe 42c, the gas supply pipe 42d, the nozzle 40b and the nozzle 40c, and is exhausted through the exhaust pipe 90.
In the first step, the APC valve 94 is appropriately controlled to adjust the inner pressure of the process chamber 22 to a predetermined pressure. For example, the inner pressure of the process chamber 22 may range from 1 Pa to 2,000 Pa, preferably from 10 Pa to 1,330 Pa. The flow rate of the HCDS gas is adjusted to a predetermined flow rate. For example, the flow rate of the HCDS gas may range from 1 sccm to 1,000 sccm. The flow rates of the N2 gas supplied through the gas supply pipes are adjusted to predetermined flow rates, respectively. For example, the flow rates of the N2 gas may range from 100 sccm to 2,000 sccm, respectively. The HCDS gas is supplied onto the substrates 24 for a predetermined time. For example, the time duration of supplying the HCDS gas onto the substrates 24 may range from 1 second to 120 seconds.
In the first step, the temperature of the heater 14 is set such that the temperature of the substrates 24 is at a predetermined temperature. For example, the temperature of the substrates 24 may range from 350° C. to 800° C., preferably from 450° C. to 800° C., more preferably from 550° C. to 750° C.
By supplying the HCDS gas onto the substrates 24 under the above-described conditions, the silicon-containing layer having a thickness of, for example, less than one atomic layer to several atomic layers is formed on the substrates 24 (that is, on a underlying film or a base film of the surfaces of the substrates 24). The silicon-containing layer may be an adsorption layer of the HCDS gas, a silicon layer, or both. Preferably, the silicon-containing layer is a layer containing silicon (Si) and chlorine (Cl).
The HCDS gas supplied into the process chamber 22 is supplied not only onto the substrates 24 but also to the surfaces of the components in the process chamber 22 (for example, the inner wall of the reaction tube 16, the inner wall of the inlet 18 and the boat 28 accommodated in the process chamber 22). Therefore, the silicon-containing layer is formed not only on the substrate 24s but also on the surfaces of the components in the process chamber 22. Similar to the silicon-containing layer formed on the substrates 24, the silicon-containing layer formed on the surfaces of the components in the process chamber 22 may be the adsorption layer of the HCDS gas, the silicon layer, or both.
In the first step, instead of the HCDS gas, for example, a gas such as tetrachlorosilane gas, that is, silicon tetrachloride (SiCl4, abbreviated as STC) gas, trichlorosilane (SiHCl3, abbreviated as TCS) gas, dichlorosilane (SiH2Cl2, abbreviated as DCS) gas and monochlorosilane (SiH3Cl, abbreviated as MCS) gas may be used as the source gas. Instead of the N2 gas, for example, rare gases such as argon (Ar) gas, helium (He) gas, neon (Ne) gas and xenon (Xe) gas may be used as the inert gas.
After the silicon-containing layer is formed on the substrates 24, the valve 46a is closed to stop the supply of the HCDS gas. In the second step, with the APC valve 94 of the exhaust pipe 90 open, the vacuum pump 96 vacuum-exhausts the inside of the process chamber 22 to remove a residual gas such as the HCDS gas in the process chamber 22 from the process chamber 22 (residual gas removing step). In the second step, by maintaining the valves 56a, 56b, 56c and 56d open, the N2 gas is continuously supplied into the process chamber 22. The N2 gas serves as a purge gas. The flow rates of the N2 gas supplied through the gas supply pipes are adjusted to predetermined flow rates, respectively. For example, the flow rates of the N2 gas may range from 100 sccm to 2,000 sccm, respectively. In the second step, instead of the N2 gas, for example, rare gases such as argon (Ar) gas, helium (He) gas, neon (Ne) gas and xenon (Xe) gas may be used as the purge gas.
In the third step, the O2 gas and the H2 gas, each of which serves as the reactive gas, is supplied onto the heated substrates 24 accommodated in the process chamber 22 under a pressure lower than the atmospheric pressure. Thereby, the layer (silicon-containing layer) formed in the first step is oxidized and modified into an oxide layer.
After the residual gas is removed, the valve 46c is opened to supply the O2 gas into the gas supply pipe 42c. The flow rate of the O2 gas supplied into the gas supply pipe 42c is adjusted by the MFC 44c. The O2 gas whose flow rate is adjusted is then supplied onto the substrates 24 in the heated and depressurized process chamber 22 through the plurality of gas supply holes 48c of the nozzle 40c.
The valve 46d is opened to supply the H2 gas into the gas supply pipe 42d. The flow rate of the H2 gas supplied into the gas supply pipe 42d is adjusted by the MFC 44d. The H2 gas whose flow rate is adjusted is then supplied onto the substrates 24 in the heated and depressurized process chamber 22 through the plurality of gas supply holes 48c of the nozzle 40c.
When passing through the gas supply pipe 42c, the H2 gas is mixed with the O2 gas in the gas supply pipe 42c. A mixed gas of the H2 gas and the O2 gas is then supplied onto the substrates 24 in the heated and depressurized process chamber 22 through the plurality of gas supply holes 48c of the nozzle 40c, and is exhausted through the exhaust pipe 90. As described above, the mixed gas of the H2 gas and the O2 gas is supplied onto the substrates 24 (O2 gas and H2 gas supplying step).
In the third step, the valve 56c may be opened to supply the inert gas such as the N2 gas through the inert gas supply pipe 52c. After the flow rate of the N2 gas is adjusted by the MFC 54c, the N2 gas whose flow rate is adjusted is supplied into the gas supply pipe 42c. In addition, the valve 56d may be opened to supply the inert gas such as the N2 gas through the inert gas supply pipe 52d. After the flow rate of the N2 gas is adjusted by the MFC 54d, the N2 gas whose flow rate is adjusted is supplied into the gas supply pipe 42c. When the N2 gas is supplied into the gas supply pipe 42c, a mixed gas of the O2 gas, the H2 gas and the N2 gas is supplied through the nozzle 40c. In the third step, instead of the N2 gas, for example, rare gases such as argon (Ar) gas, helium (He) gas, neon (Ne) gas and xenon (Xe) gas may be used as the inert gas.
In order to prevent the O2 gas and the H2 gas from entering the nozzles 40a and 40b, the valves 56a and 56b are opened to supply the N2 gas into the inert gas supply pipes 52a and 52b. The N2 gas supplied into the inert gas supply pipes 52a and 52b is then supplied into the process chamber 22 through the gas supply pipe 42a, the nozzle 40a, the cleaning gas supply pipe 62b and the nozzle 40b, and is exhausted through the exhaust pipe 90.
In the third step, the APC valve 94 is appropriately controlled to adjust the inner pressure of the process chamber 22 to a predetermined pressure lower than the atmospheric pressure. For example, the inner pressure of the process chamber 22 may range from 1 Pa to 1,000 Pa. The flow rate of the O2 gas is adjusted to a predetermined flow rate. For example, the flow rate of the O2 gas may range from 1,000 sccm to 10,000 sccm. The flow rate of the H2 gas is adjusted to a predetermined flow rate. For example, the flow rate of the H2 gas may range from 1,000 sccm to 10,000 sccm. The flow rates of the N2 gas supplied through the gas supply pipes are adjusted to predetermined flow rates, respectively. For example, the flow rates of the N2 gas may range from 100 sccm to 2,000 sccm, respectively. The O2 gas and the H2 gas are supplied onto the substrates 24 for a predetermined time. For example, the time duration of supplying the O2 gas and the H2 gas onto the substrates 24 may range from 1 second to 120 seconds.
In the third step, similar to the first step, the temperature of the heater 14 is set such that the temperature of the substrates 24 is at a predetermined temperature. For example, the temperature of the substrates 24 may range from 450° C. to 800° C., preferably from 550° C. to 750° C. When the temperature of the substrates 24 is within the above-described range, it is possible to remarkably enhance the oxidation power. In addition, it is possible to further enhance the oxidation power by adding the H2 gas to the O2 gas under the depressurized atmosphere when the temperature of the substrates 24 is within the above-described range. When the temperature of the substrates 24 is too low, it is difficult to obtain the effect of enhancing the oxidation power.
By supplying the O2 gas and the H2 gas onto the substrates 24 under the above-described conditions, the O2 gas and the H2 gas are thermally activated (excited) in non-plasma state to undergo chemical reaction which causes to form oxidation species containing, e.g., an atomic oxygen (O) free of moisture (H2O). Then, the silicon-containing layer formed on the substrates 24 in the first step is oxidized mainly by the above-formed oxidation species. Thereby, the silicon-containing layer is changed (modified) into a silicon oxide layer (SiO2 layer, hereinafter, also referred to simply as a “SiO layer”) containing a small amount of impurities such as chlorine (Cl).
According to the oxidation of the silicon-containing layer as described above, it is possible to remarkably enhance the oxidation power as compared with the case where the O2 gas is supplied alone or the water vapor (H2O) is supplied. By adding the H2 gas to the O2 gas under the depressurized atmosphere, it is possible to further enhance the oxidation power as compared with the case when the O2 gas is supplied alone or when water vapor (H2O) is supplied.
The oxidation species generated in the process chamber 22 is not only supplied to the substrates 24 but also supplied to the surfaces of the components in the process chamber 22. As a result, similar to the silicon-containing layer formed on the substrates 24, a part of the silicon-containing layer formed on the surfaces of the components in the process chamber 22 is changed (modified) into the silicon oxide layer (SiO layer).
The oxygen-containing gas may include at least one gas selected from the group consisting of the O2 gas and ozone (03) gas. The hydrogen-containing gas may include at least one gas selected from the group consisting of the H2 gas and deuterium (D2) gas.
After the silicon-containing layer is modified into the silicon oxide layer, the valve 46c is closed to stop the supply of the O2 gas. In addition, the valve 46d is closed to stop the supply of the H2 gas. In the fourth step, with the APC valve 94 of the exhaust pipe 90 open, the vacuum pump 96 vacuum-exhausts the inside of the process chamber 22 to remove the residual gas such as the O2 gas and the H2 gas in the process chamber 22 from the process chamber 22 (residual gas removing step). In the fourth step, by maintaining the valves 56a, 56b, 56c and 56d open, the N2 gas is continuously supplied into the process chamber 22. The N2 gas serves as the purge gas. The flow rates of the N2 gas supplied through the gas supply pipes are adjusted to predetermined flow rates, respectively. For example, the flow rates of the N2 gas may range from 100 sccm to 2,000 sccm, respectively. In the fourth step, instead of the N2 gas, for example, rare gases such as argon (Ar) gas, helium (He) gas, neon (Ne) gas and xenon (Xe) gas may be used as the purge gas.
By performing the cycle including the first step, the second step, the third step and the fourth step a predetermined number of times (n times), the silicon oxide film (SiO film) having a predetermined thickness is formed on the substrates 24.
After the silicon oxide film having the predetermined thickness is formed on the substrates 24, the N2 gas is supplied into the process chamber 22 through the inert gas supply pipes 52a, 52b, 52c and 52d, respectively, and then the N2 gas supplied into the process chamber 22 is exhausted through the exhaust pipe 90. The N2 gas serves as the purge gas. The inside of the process chamber 22 is purged with the inert gas (purge gas) such as the N2 gas, thus the residual gas in the process chamber 22 are removed from the process chamber 22 by supplying the N2 gas (purging step). Thereafter, the inner atmosphere of the process chamber 22 is replaced with the inert gas, and the inner pressure of the process chamber 22 is returned to the atmospheric pressure (returning to atmospheric pressure step).
Thereafter, the seal cap 100 is lowered by the boat elevator 115 and the lower end of the inlet 18 is opened. The boat 24 with the processed substrates 24 charged therein is unloaded out of the reaction tube 16 through the lower end of the inlet 18 (boat unloading step). After the boat 28 is unloaded, the shutter 110 is moved by the shutter opening/closing mechanism 112. The lower end of the inlet 18 is sealed by the shutter 110 through the O-ring 20c (shutter closing step). Then, the processed substrates 24 (that is, the substrates 24 after batch processing is performed) are then discharged from the boat 28 (wafer discharging step).
Subsequently, the cleaning process for cleaning the inside of the process chamber 22 is performed based on timing diagrams of the temperature and the pressure respectively shown in
When the SiO film is formed by the film forming process described above, the film is also deposited on the surfaces of the components in the process chamber 22 such as the inner wall of the reaction tube 16, the inner wall of the inlet 18 and the boat 28 accommodated in the process chamber 22. The deposited film is accumulated by performing (repeating) the batch processing described above, and gradually becomes thicker. The accumulated deposited film may be peeled off in subsequent substrate processing and adhere to the substrates 24. Thus, particles may be generated. Therefore, in preparation for the subsequent substrate processing, when the thickness of the accumulated deposited film reaches a predetermined thickness, the accumulated deposited film is removed from the process chamber 22. In the embodiments, an example when the predetermined thickness is 3,000 nm will be described.
The boat 28 without any substrate 24 charged therein (that is, an empty boat 28) is loaded into the process chamber 22 in the same manners as in the boat loading step of the film-forming process.
The vacuum pump 96 vacuum-exhausts the process chamber 22 until the inner pressure of the process chamber 22 reaches a desired pressure (vacuum degree). In the pressure and temperature adjusting step, the inner pressure of the process chamber 22 is measured by the pressure sensor 92, and the APC valve 94 is feedback-controlled based on the measured pressure (pressure adjusting step). The vacuum pump 96 continuously vacuum-exhausts the process chamber 22 until at least the cleaning process for cleaning the inside of the process chamber 22 is completed.
In the pressure and temperature adjusting step, the inner temperature of the process chamber 22 is stabilized at a predetermined temperature (for example, 450° C.) serving as a first temperature, as shown in
Thereafter, after the inner temperature of the process chamber 22 is stabilized at the first temperature, the rotating mechanism 102 rotates the boat 28. As the rotating mechanism 102 rotates the boat 28, the substrates 24 supported by the boat 28 are rotated. Until at least the processing of the substrates 24 is completed, the boat rotating mechanism 102 continuously rotates the boat 28 and the substrates 24. However, the boat 28 may not be rotated in the cleaning process.
Thereafter, the cleaning gas is supplied into the process chamber 22 when the inner temperature of the process chamber 22 detected by the temperature sensor 114 is the second temperature lower than the first temperature and higher than the room temperature. In the cleaning gas supplying step, first, the cleaning gas is supplied into the process chamber 22 through the nozzle 40b while the inner temperature of the process chamber 22 is being lowered from the second temperature (for example, 100° C.) to the third temperature (for example, 75° C.) lower than the second temperature (heat insulating region cleaning step), and thereafter, the cleaning gas is supplied into the process chamber 22 through the nozzle 40c while the inner temperature of the process chamber 22 is being lowered from the third temperature (for example, 75° C.) to the fourth temperature (for example, 50° C.) lower than the third temperature (wafer holding region cleaning step). It is possible to complete the heat insulating region cleaning step and the wafer holding region cleaning step by supplying the cleaning gas while the inner temperature is maintained, for a predetermined period, at their final temperatures (for example, 75° C. for the heat insulating region cleaning step and 50° C. for the wafer holding region cleaning step), respectively. In addition, the second temperature is not limited to 100° C., the third temperature is not limited to 75° C., and the fourth temperature is not limited to 50° C. Hereinafter, the heat insulating region cleaning step and the wafer holding region cleaning step will be described in detail.
First, the valve 66b is opened to supply the cleaning gas such as the HF gas into the gas supply pipe 62b. The flow rate of the HF gas supplied into the gas supply pipe 62b is adjusted by the MFC 64b. The HF gas whose flow rate is adjusted is then supplied into the process chamber 22 through the gas supply hole 48b of the nozzle 40b, and contacts the surfaces of the components such as the inner wall of the inlet 18, the upper surface of the seal cap 100 and a side surface of the rotating shaft 104. The HF gas is then exhausted through the exhaust pipe 90. Specifically, the deposits deposited on the components constituting the heat insulating region such as the inlet 18, the heat insulating part 30 and the rotating shaft 104 are removed by reacting with the HF gas. In addition, the nozzle 40b is configured to supply the HF gas directly to the heat insulating part 30 through the gas supply hole 48b. Particularly, since the nozzle 40b is configured to supply the HF gas directly to the heat insulating part 30, it is possible to efficiently remove the deposits deposited on the heat insulating part 30. Since the HF gas supplied through the nozzle 40b is in contact with the other components in the process chamber 22 and then exhausted through the exhaust pipe 90, the deposits deposited on the components constituting the wafer holding region such as the boat 28 may be removed. In the heat insulating region cleaning step, the valves 56c and 56d are opened to supply the inert gas such as the N2 gas through the nozzle 40c.
In the heat insulating region cleaning step, preferably, in order to prevent the HF gas from entering the nozzle 40a, the valve 56a is opened to supply the N2 gas into the inert gas supply pipe 52a. The N2 gas supplied into the inert gas supply pipe 52a is then supplied into the process chamber 22 through the gas supply pipe 42a and the nozzle 40a, and is exhausted through the exhaust pipe 90.
In the heat insulating region cleaning step, the HF gas is supplied through the nozzle 40b. When inner temperature of the process chamber 22 is lowered to about 75° C. as the third temperature, the valves 66b, 56c and 56d are closed to stop the supply of the HF gas through the cleaning gas supply pipe 62b and to stop the supply of the N2 gas through the inert gas supply pipes 52c and 52d.
Thereafter, the valve 66a is opened to supply the cleaning gas such as the HF gas into the gas supply pipe 62a. The flow rate of the HF gas supplied into the gas supply pipe 62a is adjusted by the MFC 64a. The HF gas whose flow rate is adjusted is then supplied into the process chamber 22 through the plurality of gas supply holes 48c of the nozzle 40c, and contacts the surfaces of the components such as the inner wall of the reaction tube 16, the inner wall of the inlet 18 and the surface of the boat 28. The HF gas is then exhausted through the exhaust pipe 90. Specifically, the deposits deposited on the components constituting the wafer holding region such as the reaction tube 16, the inlet 18 and the boat 28 are removed by reacting with the HF gas. Since the HF gas supplied through the plurality of gas supply holes 48c of the nozzle 40c is in contact with the other components in the process chamber 22 and then exhausted through the exhaust pipe 90, the deposits deposited on the components constituting the heat insulating region may be removed. In the wafer holding region cleaning step, the valve 56b is opened to supply the inert gas such as the N2 gas through the nozzle 40b.
In the wafer holding region cleaning step, preferably, in order to prevent the HF gas from entering the nozzle 40a, the valve 56a is opened to supply the N2 gas into the inert gas supply pipe 52a. The N2 gas supplied into the inert gas supply pipe 52a is then supplied into the process chamber 22 through the gas supply pipe 42a and the nozzle 40a, and is exhausted through the exhaust pipe 90.
In the wafer holding region cleaning step, the HF gas is supplied through the nozzle 40c. When inner temperature of the process chamber 22 is lowered to about 50° C. as the fourth temperature, the valves 66a and 56b are closed to stop the supply of the HF gas through the cleaning gas supply pipe 62a and to stop the supply of the N2 gas through the inert gas supply pipe 52b.
In the cleaning gas supplying step including the heat insulating region cleaning step and the wafer holding region cleaning step, the APC valve 94 is adjusted to control (adjust) the inner pressure of the process chamber 22. The inner pressure of the process chamber 22 may be controlled to be constant at a predetermined pressure (for example, 13 kPa), or may be varied from about 0.1 kPa (first pressure) to 26 kPa (second pressure). For example, the inner pressure of the process chamber 22 may be varied such that a period (hereinafter, also referred to as a “time duration”) t1 during which the inner pressure of the process chamber 22 is lower than a predetermined high pressure (for example, 10 kPa) and a period t2 during which the inner pressure of the process chamber 22 is equal to or higher than the predetermined high pressure are repeated. Specifically, the inner pressure of the process chamber 22 may be varied such that the period t1 during which the inner pressure of the process chamber 22 is lower than the predetermined high pressure is longer than the period t2 during which the inner pressure of the process chamber 22 is equal to or higher than the predetermined high pressure. As shown in
In the cleaning gas supplying step, the flow rate of the HF gas adjusted by each of the MFCs 64a and 64b is, for example, 2.0 slm. The flow rates of the N2 gas adjusted by the MFCs 54a, 54b, 54c and 54d are, for example, 3.0 slm in total. That is, it is preferable to control the flow rates of the HF gas and the N2 gas such that the HF gas whose flow rate is 40% of that of the N2 gas is supplied into the process chamber 22 in the heat insulating region cleaning step and the wafer holding region cleaning step. As a result, the concentration of the HF gas in the process chamber 22 is increased. Therefore, it is possible to improve the etching rate greatly as compared with that of the comparative example described later. In addition, it is possible to improve the efficiency of using the HF gas. When the flow rates of the HF gas and the N2 gas are controlled as described above, the etching rate is about 1900 Å/cycle as shown in
As shown in
After the deposits (deposited films) are removed by supplying the HF gas into the process chamber 22 when the inner temperature of the process chamber is at 50° C. which is the fourth temperature or by supplying the HF gas into the process chamber 22 for a predetermined time during which the inner temperature of the process chamber 22 is maintained at 50° C. which is the fourth temperature, the valves 56a, 56b, 56c are 56d opened to supply the inert gas such as the N2 gas into the process chamber 22 through the inert gas supply pipes 52a, 52b, 52c and 52d, respectively. The N2 gas supplied into the process chamber 22 is then exhausted through the exhaust pipe 90. The N2 gas serves as the purge gas. The inside of the process chamber 22 is purged with the inert gas (purge gas) such as the N2 gas, thus the residual gas in the process chamber 22 is removed from the process chamber 22 by supplying the N2 gas (purging step). Thereafter, the inner atmosphere of the process chamber 22 is replaced with the inert gas, and the inner pressure of the process chamber 22 is returned to the atmospheric pressure (returning to atmospheric pressure step).
Thereafter, the boat 24 is unloaded out of the reaction tube 16 in the same manners as in the boat unloading step of the film-forming process. Thereafter, the lower end opening of the inlet 18 is sealed by the shutter 110. In addition, after the lower end opening of the inlet 18 is sealed or the boat 24 is unloaded from the reaction tube 16, the inner temperature of the process chamber 22 may be elevated to a predetermined standby temperature (for example, 450° C.).
According to the cleaning result of the heat insulating region cleaning step shown in
The nozzle 40b is configured to supply the gas such as the cleaning gas to the heat insulating region. Therefore, as shown in
However, according to the embodiments, the cleaning process is performed while changing (lowering or dropping) the inner temperature of the process chamber 22. Therefore, it is possible to shorten the time required for performing the cleaning process. According to the embodiments, first, the heat insulating region cleaning step is performed by supplying the cleaning gas to the heat insulating region through the nozzle 40b while dropping the inner temperature of the process chamber 22 from 100° C. to 75° C., wherein it is known that the heat insulating region should be cleaned at relatively high temperatures. Thereafter, the wafer holding region cleaning step is performed by supplying the cleaning gas to the wafer holding region through the nozzle 40c while dropping the inner temperature of the process chamber 22 from 75° C. to 50° C. That is, according to the embodiments, by performing the heat insulating region cleaning step and the wafer holding region cleaning step at different temperature ranges, it is possible to shorten the time required for performing the cleaning process while removing the deposits such as the reaction by-products adhered to the heat insulating region and the wafer holding region. It is also possible to suppress the variation of the etching rate depending on the location in a cleaning region such as the heat insulating region and the cleaning the wafer holding region.
Hereinafter, a cleaning process according to the comparative example of the embodiments will be described.
As shown in
In a cleaning gas supplying step of the comparative example, as shown in
According to the cleaning process of the embodiment, the average etching rate obtained by performing the heat insulating region cleaning step is about 1,900 Å/cycle as shown in
According to the cleaning process of the embodiments shown in
For example, when cleaning the SiO film using the HF gas, it is preferable to perform the cleaning process at about 30° C., since the etching rate improves as the temperature is as low as 100° C. or less. However, it takes a lot of time to lower the temperature to a processing temperature (or standby temperature). For example, as shown in
However, according to the embodiments, first, the heat insulating region cleaning step is performed by supplying the cleaning gas through the nozzle 40b while lowering the inner temperature of the process chamber 22 from 100° C. to 75° C., and subsequently, the wafer holding region cleaning step is performed by supplying the cleaning gas through the nozzle 40c while lowering the inner temperature of the process chamber 22 from 75° C. to 50° C. Thereby, it is possible to shorten the time required for lowering the temperature. In addition, for example, it is possible to remove the reaction by-products in the heat insulating region and the wafer holding region more meticulously as compared with the case where the cleaning gas is supplied while maintaining the inner temperature of the process chamber 22 at a constant temperature as shown in the comparative example. Thus, it is possible to shorten the time required for cleaning the inside of the process chamber 22, and to improve the throughput.
According to the embodiments, the second temperature may not be the same as the temperature at which the heat insulating region cleaning step is started or terminated, and the third temperature may not be the same as the temperature at which the wafer holding region cleaning step is started or terminated.
According to the embodiments, one or more advantageous effects described below can be achieved.
(a) According to the embodiments, it is possible to shorten the time required for performing the cleaning process by performing the cleaning process under 100° C. and varying (lowering) the inner temperature of the process chamber 22 during the cleaning process.
(b) According to the embodiments, the cleaning process is performed by changing the region to be cleaned according to the inner temperature of the process chamber 22. Therefore, it is possible to shorten the time required for performing the cleaning process while suppressing the variation of the etching rate depending on the location in the cleaning region.
(c) According to the embodiments, the cleaning process is performed by varying the inner pressure of the process chamber. As a result, the flow velocity of the cleaning gas is decreased and the time during which the HF gas remains in the process chamber 22 is increased. Therefore, it is possible to improve the efficiency of using the HF gas and the etching rate. Since the number of cycles necessary for removing the deposits in the heat insulating region cleaning step, for example, is greatly reduced, it is also possible to shorten the time required for performing the cleaning process.
(d) According to the embodiments, the cleaning process is performed by supplying the HF gas and the N2 gas such that the flow rate of the HF gas is lower than that of the N2 gas. As a result, it is possible to improve the efficiency of using the HF gas and the etching rate. Since the number of cycles necessary for removing the deposits in the cleaning process is greatly reduced, it is also possible to shorten the time required for performing the cleaning process.
(e) According to the embodiments, the cleaning process is performed by considering the trade-off relationships between the temperature suitable for performing the cleaning process using the HF gas and the cooling time (or temperature lowering time) required for lowering the inner the temperature of the process chamber 22. Therefore, it is possible to shorten the time required for performing the cleaning process while suppressing the variation of the etching rate depending on the location in the cleaning region.
(f) According to the embodiments, the cleaning process may be performed by adjusting the cleaning conditions (for example, by increasing the concentration of the cleaning gas). Thus, it is possible to expand the temperature range suitable for performing the cleaning process. Since the cleaning process may be started at a temperature higher than the conventional cleaning temperature, it is possible to shorten the time required for performing the cleaning process.
(g) According to the embodiments, the cleaning process may be performed by adjusting the cleaning conditions (for example, by increasing the concentration of the cleaning gas). Therefore, it is possible to suppress the variation of the etching rate depending on the location in the cleaning region.
(h) According to the embodiments, the cleaning process may be performed by adjusting the cleaning conditions (for example, by increasing the concentration of the cleaning gas). Therefore, it is possible to set the cleaning region according to the inner the temperature of the process chamber 22. As a result, it is possible to suppress the variation of the etching rate depending on the location in the cleaning region.
Hereinafter, a modified example of the cleaning process according to the embodiments will be described with reference to
According to a cleaning process of the modified example, after the inner temperature of the process chamber 22 is lowered from 450° C. to 50° C., the wafer holding region cleaning step is performed by supplying the HF gas through the nozzle 40c while elevating the inner temperature of the process chamber 22 from 50° C. to 75° C., and the heat insulating region cleaning step is performed by supplying the HF gas through the nozzle 40b while elevating the inner temperature of the process chamber 22 from 75° C. to 100° C. After the heat insulating region cleaning step is completed, the steps such as a purging step at 100° C. as a standby temperature, the returning to atmospheric pressure step and the boat unloading step are performed.
According to the modified example, the same advantageous effects as the embodiments may be obtained.
While the above-described embodiments are described by way of an example in which the SiO film, that is, a silicon-based film containing silicon as a semiconductor element is formed, the above-described technique is not limited thereto. For example, the above-described technique may be applied to the formations of other films such as a metal-based film containing a metal element such as titanium (Ti), zirconium (Zr), hafnium (Hf), tantalum (Ta), aluminum (Al) and molybdenum (Mo).
As described above, the above-described technique may be applied not only to the formation of the silicon-based film but also to the formations of other films such as the metal-based film. The same advantageous effects as the embodiments may be obtained when the above-described technique is applied to the formation of the metal-based film. That is, the above-described technique may be suitably applied to the formation of the film containing a predetermined element such as a semiconductor element or a metal element.
While the above-described embodiments are described based on a case in which the cleaning gas is supplied into the process chamber 22 after the boat 28 is loaded in the cleaning process (that is, the cleaning process for cleaning the inside of the process chamber 22 is performed with the boat 28 accommodated in the process chamber 22), the above-described technique is not limited thereto. For example, when the cleaning of the boat 28 is unnecessary, the boat loading step may be omitted and the cleaning gas may be supplied into the process chamber 22 without the boat 28 loaded (that is, the boat 28 is not accommodated in the process chamber 22). That is, the above-described technique may be applied to the cleaning process in which the boat loading step is omitted.
While the above-described embodiments are described based on a case in which the cleaning gas is sequentially supplied through one of the nozzle 40b and the nozzle 40c, the above-described technique is not limited thereto. For example, above-described technique may also be applied to a case where the cleaning gas is supplied simultaneously through the nozzle 40b and the nozzle 40c. Further, the above-described technique is not limited to the above-described case in which the cleaning gas supply pipe 62a is connected to the gas supply pipe 42c. For example, above-described technique may also be applied to a case where the cleaning gas supply pipe 62a is connected to the gas supply pipe 42a or to both of the gas supply pipe 42a and the gas supply pipe 42c.
The above-described technique may also be embodied by changing an existing process recipe and an existing cleaning recipe stored in a predetermined substrate processing apparatus to a new process recipe and a new cleaning recipe according to the embodiments. When changing the existing process recipe and the existing cleaning recipe to the new process recipe and the new cleaning recipe, the new process recipe and the new cleaning recipe may be installed in the predetermined substrate processing apparatus via the telecommunication line or the recording medium in which the new process recipe and the new cleaning recipe are stored. The existing process recipe and the existing cleaning recipe may be changed to the new process recipe and the new cleaning recipe by operating the input/output device of the predetermined substrate processing apparatus.
The above-described technique is not limited to the semiconductor manufacturing apparatus, but may also be applied to, e.g., an apparatus for processing a glass substrate such as an LCD manufacturing apparatus. While the above-described embodiments are described based on a case in which the cleaning process is performed after the film is deposited on the substrates, the above-described technique is not limited thereto. For example, the above-described technique may also be applied to the processes such as an oxidation process, a diffusion process and an annealing process. The above-described embodiments and modified examples may be appropriately combined. The processing conditions of the combinations may be substantially the same as the above-described embodiments or the modified examples.
The above-described technique may be applied to the cleaning process of the substrate processing apparatus capable of processing the substrates, particularly to the cleaning process capable of shortening the time required for performing the cleaning process.
According to the technique described herein, it is possible to suppress the variation of the etching rate depending on the location in the cleaning region and to shorten the time required for performing the cleaning process.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2016-116528 | Jun 2016 | JP | national |
This application is a continuation of International Application No. PCT/JP2017/010219, filed on Mar. 14, 2017, which claims priority under 35 U.S.C. § 119 to Application No. JP 2016-116528 filed on Jun. 10, 2016, the entire contents of which are hereby incorporated by reference.
| Number | Date | Country | |
|---|---|---|---|
| Parent | PCT/JP2017/010219 | Mar 2017 | US |
| Child | 16215303 | US |
