JP2016174059A - Thin film formation method and thin film formation device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a thin film formation method and a thin film formation device, which can improve productivity.SOLUTION: A thin film formation method of repeating: a storage process of storing a semiconductor wafer W in a reaction tube 2; a thin film formation process of forming a shin film on the semiconductor wafer W stored in the reaction tube 2; and a carry-out process of carrying out to the outside of the reaction tube 2, the semiconductor wafer W where the thin film is formed. The thin film formation method further comprises between the carry-out process and the storage process, a carbon purge process of supplying a carbon-containing gas to inside of the reaction tube 2 to cause a surface of an adhering substance which adheres to the inside of the device to be carbon terminated and cause a gas which is generated from the thin film and remains inside the device to be carbon terminated.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a thin film forming method and a thin film forming apparatus.

  As a method for forming a thin film, for example, a silicon nitride film or a silicon oxide film, a CVD (Chemical Vapor Deposition) method or an ALD (Atomic Layer Deposition) method is used. Various thin film forming methods for forming a book film have been proposed. For example, Patent Document 1 discloses a method of forming a thin film at a low temperature of 300 ° C. to 600 ° C.

JP 2004-281853 A

  By the way, the formed book film is deposited (attached) not only on the surface of the semiconductor wafer but also inside the heat treatment apparatus such as the inner wall of the reaction tube and various jigs. In particular, in the formation of a silicon nitride film at a low temperature, a large amount of outgas is generated from the formed silicon nitride film, and deposits are easily attached to the inside of the heat treatment apparatus. When a thin film is formed in a state where the deposits are attached in the heat treatment apparatus, stress is generated due to the difference in thermal expansion coefficient between quartz constituting the reaction tube and the deposits, and the deposits are broken by this stress. Thus, what the deposit | attachment broke becomes particle | grains and becomes a cause which reduces productivity. Further, there is a possibility that the inside of the apparatus is corroded. For this reason, there is a demand for a thin film forming method and the like that can suppress corrosion inside the apparatus and generation of particles and improve productivity.

  The present invention has been made in view of the above problems, and an object of the present invention is to provide a thin film forming method and a thin film forming apparatus capable of improving productivity.

In order to achieve the above object, a thin film forming method according to the first aspect of the present invention comprises:
A housing step of housing the object to be processed in the reaction chamber;
A thin film forming step of forming a thin film on the target object accommodated in the reaction chamber;
A thin film forming method that repeats an unloading step of unloading the object on which the thin film is formed out of the reaction chamber,
Between the unloading step and the containing step, a gas containing carbon is supplied into the reaction chamber, and the surface of the deposit attached to the inside of the apparatus is terminated with carbon, and is generated from the thin film and remains inside the apparatus. It is characterized by comprising a carbon purge step for terminating the gas with carbon.

  In the carbon purge step, for example, ethylene, propylene, or acetylene is used as the gas containing carbon supplied into the reaction chamber.

  The thin film is, for example, a silicon nitride film, a silicon oxide film, a silicon nitride film containing boron, or a film containing silicon, boron, carbon, and nitrogen.

  In the carbon purge step, for example, the pressure in the reaction chamber is set to 13.3 Pa to 1.33 kPa.

  In the carbon purge step, for example, 0.1 slm to 10 slm of a gas containing carbon is supplied into the reaction chamber.

A thin film forming apparatus according to a second aspect of the present invention provides:
A reaction chamber for accommodating a workpiece,
A film forming gas supply means for supplying a film forming gas into the reaction chamber;
A carbon gas supply means for supplying a gas containing carbon into the reaction chamber;
Control means for controlling each part of the apparatus,
The control means includes
The object to be processed is accommodated in the reaction chamber, the film forming gas supply means is controlled to form a thin film on the object to be processed accommodated in the reaction chamber, and the object to be processed on which the thin film is formed is reacted with the reaction. Repeat the process of taking it out of the room,
A gas containing carbon in the reaction chamber is controlled by controlling the carbon gas supply means while the object to be processed is accommodated in the reaction chamber after unloading the object to be processed in which the thin film is formed. The surface of deposits supplied and adhered inside the apparatus is carbon-terminated, and the gas generated from the thin film and remaining inside the apparatus is carbon-terminated.

  According to the present invention, productivity can be improved.

It is a figure which shows the thin film forming apparatus of embodiment of this invention. It is a figure which shows the structure of the control part of FIG. It is a figure explaining the thin film formation method. It is a figure which shows the relationship between carbon purge gas and the etching amount.

  Hereinafter, a thin film forming method and a thin film forming apparatus according to an embodiment of the present invention will be described. In this embodiment, a case where a batch type vertical heat treatment apparatus is used as the thin film forming apparatus of the present invention will be described as an example. FIG. 1 shows the configuration of the heat treatment apparatus of the present embodiment.

  As shown in FIG. 1, the heat treatment apparatus 1 includes a reaction tube 2 having a substantially cylindrical shape and a ceiling. The reaction tube 2 is arranged so that its longitudinal direction is in the vertical direction. The reaction tube 2 is made of a material excellent in heat resistance and corrosion resistance, for example, quartz.

  A substantially cylindrical manifold 3 is provided below the reaction tube 2. The upper end of the manifold 3 is airtightly joined to the lower end of the reaction tube 2. An exhaust pipe 4 for exhausting the gas in the reaction tube 2 is airtightly connected to the manifold 3. The exhaust pipe 4 is provided with a pressure adjusting unit 5 including a valve control unit 125, a vacuum pump 126 and the like, which will be described later, and adjusts the inside of the reaction tube 2 to a desired pressure (degree of vacuum).

  A lid 6 is disposed below the manifold 3 (reaction tube 2). The lid 6 is made of a material excellent in heat resistance and corrosion resistance, for example, quartz. The lid 6 is configured to be movable up and down by a boat elevator 127 described later. When the lid 6 is raised by the boat elevator 127, the lower side (furnace port portion) of the manifold 3 (reaction tube 2) is closed, and the boat 6 When the lid body 6 is lowered by the elevator 127, the lower side (furnace port portion) of the reaction tube 2 is opened.

  On the lid 6, a heat insulating cylinder 8 is placed to prevent the temperature in the reaction tube 2 from decreasing from the furnace port portion of the reaction tube 2. A wafer boat 9 is placed on the heat insulating cylinder 8. The wafer boat 9 is made of, for example, quartz. The wafer boat 9 is configured to accommodate a plurality of semiconductor wafers W at predetermined intervals in the vertical direction. Note that a rotary table on which the wafer boat 9 that accommodates the semiconductor wafers W is rotatably mounted may be provided on the heat insulating cylinder 8, and the wafer boat 9 may be mounted thereon. In these cases, it becomes easy to control the semiconductor wafers W accommodated in the wafer boat 9 to a uniform temperature.

  Around the reaction tube 2, for example, a heater unit 10 made of a resistance heating element is provided so as to surround the reaction tube 2. The heater 10 heats the inside of the reaction tube 2 to a predetermined temperature, and as a result, the semiconductor wafer W is heated to a predetermined temperature. The heater unit 10 includes, for example, heaters 11 to 15 arranged in five stages. Each of the heaters 11 to 15 is connected to a power controller, which will be described later, and by independently supplying power to the power controller, each of the heaters 11 to 15 can be independently heated to a desired temperature. it can.

  The manifold 3 is provided with a plurality of processing gas supply pipes for supplying a processing gas into the reaction tube 2. In FIG. 1, three process gas supply pipes 21 to 23 that supply process gas to the manifold 3 are illustrated.

  The process gas supply pipes 21 to 23 are provided with flow rate adjusting units 24 to 26, respectively. As will be described later, the flow rate adjusting units 24 to 26 include a mass flow controller (MFC 124) for adjusting the flow rate of the processing gas flowing in the processing gas supply pipes 21 to 23, and the like. For this reason, the processing gas supplied from the processing gas supply pipes 21 to 23 is adjusted to a desired flow rate by the flow rate adjusting units 24 to 26 and supplied to the reaction pipe 2 respectively.

  The processing gas supplied from the processing gas supply pipes 21 to 23 varies depending on the type of thin film to be formed. For example, when forming a silicon nitride film, source gas, nitriding gas, dilution gas, purge gas, and carbon purge gas are used. is there.

  The source gas is a Si source that adsorbs the source (Si) to the object to be processed, and is used in an adsorption step described later. In this example, dichlorosilane (DCS) is used as the Si source.

The nitriding gas is a gas for nitriding the adsorbed source (Si), and is used in a nitriding step described later. In this example, ammonia (NH ₃ ) is used as the nitriding gas.

The dilution gas is a gas that dilutes the source gas, the nitriding gas, and the like, and for example, nitrogen (N ₂ ) is used.
The purge gas is a gas that exhausts the gas in the reaction tube 2, and for example, nitrogen (N ₂ ) is used.

The carbon purging gas is a gas that suppresses the generation of corrosion and particles by terminating the surface of the outgas generated from the formed book film and the deposit attached to the inside of the apparatus, and for example, carbonization having an unsaturated bond. There are hydrogen compounds and the like. Examples of the hydrocarbon compound having an unsaturated bond include ethylene (C ₂ H ₄ ), propylene (C ₃ H ₆ ), and acetylene (C ₂ H ₂ ).

  Further, the heat treatment apparatus 1 includes a control unit (controller) 100 for controlling processing parameters such as a gas flow rate in the reaction tube 2, a pressure, and a processing atmosphere temperature. FIG. 2 shows the configuration of the control unit 100.

  As shown in FIG. 2, an operation panel 121, a temperature sensor 122, a pressure gauge 123, an MFC 124, a valve control unit 125, a vacuum pump 126, a boat elevator 127, a heater controller 128, and the like are connected to the control unit 100.

  The operation panel 121 includes a display screen and operation buttons, transmits an operation instruction of the operator to the control unit 100, and displays various information from the control unit 100 on the display screen.

The temperature sensor 122 measures the temperature of each part such as the inside of the reaction tube 2 and the exhaust pipe 4 and notifies the control unit 100 of the measured value.
The pressure gauge 123 measures the pressure in each part such as the inside of the reaction tube 2 and the exhaust pipe 4 and notifies the control unit 100 of the measured value.

  The MFC 124 is arranged in each pipe such as the processing gas supply pipes 21 to 23, and controls the flow rate of the gas flowing through each pipe to the amount instructed by the control unit 100, and measures the flow rate of the actually flowed gas. , Notify the control unit 100.

The valve control unit 125 is arranged in each pipe and controls the opening degree of the valve arranged in each pipe to a value instructed from the control unit 100.
The vacuum pump 126 is connected to the exhaust pipe 4 and exhausts the gas in the reaction pipe 2.

  The boat elevator 127 raises the lid 6 to load the wafer boat 9 (semiconductor wafer W) into the reaction tube 2 and lowers the lid 6 to react the wafer boat 9 (semiconductor wafer W). Unload from within tube 2.

  The heater controller 128 is for individually controlling the heaters 11 to 15. In response to an instruction from the control unit 100, the heater controller 128 energizes the heaters 11 to 15 to heat them, and the heaters 11 to 15. Are measured individually and notified to the control unit 100.

  The control unit 100 includes a recipe storage unit 111, a ROM (Read Only Memory) 112, a RAM (Random Access Memory) 113, an I / O port (Input / Output Port) 114, a CPU (Central Processing Unit) 115, The bus 116 interconnects these components.

  The recipe storage unit 111 stores a setup recipe and a plurality of process recipes. At the beginning of the manufacture of the heat treatment apparatus 1, only the setup recipe is stored. The setup recipe is executed when a thermal model or the like corresponding to each processing apparatus is generated. The process recipe is a recipe prepared for each heat treatment (process) actually performed by the user. Each process from loading of the semiconductor wafer W to the reaction tube 2 until unloading of the processed semiconductor wafer W is performed. The temperature change, the pressure change in the reaction tube 2, the start and stop timings and supply amounts of various gases are defined.

The ROM 112 is a recording medium that includes an EEPROM (Electrically Erasable Programmable Read Only Memory), a flash memory, a hard disk, and the like, and stores an operation program of the CPU 115 and the like.
The RAM 113 functions as a work area for the CPU 115.

  The I / O port 114 is connected to the operation panel 121, the temperature sensor 122, the pressure gauge 123, the MFC 124, the valve control unit 125, the vacuum pump 126, the boat elevator 127, the heater controller 128, and the like, and controls input / output of data and signals. To do.

The CPU 115 constitutes the center of the control unit 100 and executes a control program stored in the ROM 112. Further, the CPU 115 controls the operation of the heat treatment apparatus 1 in accordance with a recipe (process recipe) stored in the recipe storage unit 111 in accordance with an instruction from the operation panel 121. That is, the CPU 115 causes the temperature sensor 122, the pressure gauge 123, the MFC 124, and the like to measure the temperature, pressure, flow rate, and the like of each part such as in the reaction tube 2 and the exhaust tube 4, and based on this measurement data, the heater controller 128, Control signals and the like are output to the MFC 124, the valve control unit 125, the vacuum pump 126, and the like, and the above-described units are controlled so as to follow the process recipe.
The bus 116 transmits information between the units.

  Next, a thin film forming method using the heat treatment apparatus 1 configured as described above will be described with reference to a recipe (time sequence) shown in FIG. In the book film forming method of the present embodiment, the present invention will be described by taking as an example the case where a silicon nitride film is formed on a semiconductor wafer W by the ALD method.

As shown in FIG. 3, the ALD method of the present embodiment includes an adsorption step for adsorbing silicon (Si) on the surface of the semiconductor wafer W and a nitridation step for nitriding the adsorbed Si. One cycle of the ALD method is shown. Also, as shown in FIG. 3, DCS is used as the Si source gas, ammonia (NH ₃ ) is used as the nitriding gas, nitrogen (N ₂ ) is used as the dilution gas, and methylene (C ₂ H ₄ ) is used as the carbon dioxide purge gas. A silicon nitride film having a desired thickness is formed on the semiconductor wafer W by executing (repeating) the cycle shown in the recipe of FIG.

  In the following description, the operation of each part constituting the heat treatment apparatus 1 is controlled by the control unit 100 (CPU 115). In addition, as described above, the temperature, pressure, gas flow rate, etc. in the reaction tube 2 in each process are controlled by the control unit 100 (CPU 115) by the heater controller 128 (heater unit 10) and the MFC 124 (processing gas supply pipe 21). By controlling the valve control unit 125 and the vacuum pump 126, the conditions according to the recipe shown in FIG. 3 are set.

  First, the inside of the reaction tube 2 is maintained at a predetermined load temperature, for example, 450 ° C. as shown in FIG. Next, the wafer boat 9 containing the semiconductor wafers W is placed on the lid body 6. Then, the lid 6 is lifted and loaded by the boat elevator 127, and the semiconductor wafer W (wafer boat 9) is accommodated in the reaction tube 2 (wafer charging step).

  Subsequently, a silicon nitride film forming step for forming a silicon nitride film on the semiconductor wafer W is performed. First, the inside of the reaction tube 2 is set to a predetermined temperature, for example, 630 ° C. as shown in FIG. In addition, a predetermined amount of nitrogen is supplied into the reaction tube 2 from the processing gas supply tube 21 and the like, and the gas in the reaction tube 2 is exhausted, so that the reaction tube 2 has a predetermined pressure, for example, as shown in FIG. Thus, it is set to 133 Pa (1 Torr) (stabilization step).

  Next, an adsorption step for adsorbing Si on the surface of the semiconductor wafer W is executed. The adsorption step is a process of supplying a source gas to the semiconductor wafer W and adsorbing Si on the surface thereof.

  In the adsorption step, a predetermined amount of DCS as the Si source from the processing gas supply pipe 21 or the like, for example, 0.3 slm as shown in FIG. 3D, and a predetermined amount of DCS as shown in FIG. Nitrogen is supplied into the reaction tube 2 (flow process).

  Here, the temperature in the reaction tube 2 is preferably set to 450 ° C. to 630 ° C. If the temperature is lower than 450 ° C., the silicon nitride film may not be formed. If the temperature in the reaction tube 2 is higher than 630 ° C., the film quality and film thickness uniformity of the formed silicon nitride film deteriorate. This is because there is a risk that it will occur.

  The supply amount of DCS is preferably 10 sccm to 10 slm. This is because if it is less than 10 sccm, there is a possibility that sufficient Si is not supplied to the surface of the semiconductor wafer W, and if it is more than 10 slm, there is a possibility that Si that does not contribute to the reaction will increase. The supply amount of DCS is more preferably 0.1 slm to 3 slm. This is because the reaction between the surface of the semiconductor wafer W and Si is promoted by setting it in such a range.

  The pressure in the reaction tube 2 is preferably 0.133 Pa (0.001 Torr) to 13.3 kPa (100 Torr). This is because the reaction between the surface of the semiconductor wafer W and Si can be promoted by setting the pressure within this range. The pressure in the reaction tube 2 is more preferably 40 Pa (0.3 Torr) to 400 Pa (3 Torr). This is because the pressure in the reaction tube 2 can be easily controlled by setting the pressure within this range.

  The DCS supplied into the reaction tube 2 is heated and activated in the reaction tube 2. For this reason, when DCS is supplied into the reaction tube 2, the surface of the semiconductor wafer W reacts with the activated Si, and Si is adsorbed on the surface of the semiconductor wafer W.

  When a predetermined amount of Si is adsorbed on the surface of the semiconductor wafer W, the supply of DCS and nitrogen from the processing gas supply pipe 21 and the like is stopped. And while discharging | emitting the gas in the reaction tube 2, as shown in FIG.3 (c), for example, as shown in FIG.3 (c), a predetermined amount of nitrogen is supplied in the reaction tube 2 from the process gas supply tube 21, etc. The gas is discharged out of the reaction tube 2 (purge, vacuum process).

  Subsequently, the inside of the reaction tube 2 is set to a predetermined temperature, for example, 630 ° C. as shown in FIG. Further, as shown in FIG. 3C, a predetermined amount of nitrogen is supplied into the reaction tube 2 from the processing gas supply tube 21 and the like, and the gas in the reaction tube 2 is discharged, so that the reaction tube 2 is kept at a predetermined pressure. For example, as shown in FIG. 3B, it is set to 133 Pa (1 Torr).

Next, a nitriding step for nitriding the surface of the semiconductor wafer W is performed. The nitriding step is a process of nitriding the adsorbed Si by supplying a nitriding gas onto the semiconductor wafer W on which Si is adsorbed. In the present embodiment, Si adsorbed by supplying ammonia (NH ₃ ) onto the semiconductor wafer W is nitrided.

  In the nitriding step, a predetermined amount of ammonia, for example, 10 slm is supplied into the reaction tube 2 from the processing gas supply tube 21 or the like, for example, as shown in FIG. Further, as shown in FIG. 3C, a predetermined amount of nitrogen as a dilution gas is supplied into the reaction tube 2 from the processing gas supply tube 21 or the like (flow process).

  Here, the supply amount of ammonia is preferably 1 sccm to 50 slm, more preferably 0.1 slm to 20 slm, and most preferably 1 slm to 10 slm. This is because, when the thickness is within this range, sufficient nitridation for forming the silicon nitride film can be performed.

  The pressure in the reaction tube 2 is preferably 0.133 Pa (0.001 Torr) to 13.3 kPa (100 Torr). This is because by setting the pressure in such a range, the nitridation of Si on the surface of the semiconductor wafer W can be promoted. The pressure in the reaction tube 2 is more preferably 40 Pa (0.3 Torr) to 400 Pa (3 Torr). This is because the pressure in the reaction tube 2 can be easily controlled by setting the pressure within this range.

  When ammonia is supplied into the reaction tube 2, Si adsorbed on the semiconductor wafer W is nitrided, and a silicon nitride film is formed on the semiconductor wafer W. When a silicon nitride film having a desired thickness is formed on the semiconductor wafer W, the supply of ammonia from the processing gas supply pipe 21 and the like is stopped. Further, the supply of nitrogen from the processing gas supply pipe 21 or the like is stopped. Then, the gas in the reaction tube 2 is discharged, and a predetermined amount of nitrogen is supplied from the processing gas supply tube 21 into the reaction tube 2 to react the gas in the reaction tube 2 as shown in FIG. Drain out of the tube 2 (purge, vacuum process).

  This completes one cycle of the ALD method, which consists of an adsorption step and an oxidation step. Subsequently, one cycle of the ALD method starting from the adsorption step is started again. Then, this cycle is repeated a predetermined number of times. Thereby, a silicon nitride film having a desired thickness is formed on the semiconductor wafer W.

  When a silicon nitride film having a desired thickness is formed on the semiconductor wafer W, the heater 10 maintains the inside of the reaction tube 2 at a predetermined load temperature, for example, 450 ° C. as shown in FIG. A predetermined amount of nitrogen is supplied into the reaction tube 2 from the processing gas supply tube 21 and the like, the gas in the reaction tube 2 is discharged to the outside of the reaction tube 2, and the inside of the reaction tube 2 is returned to normal pressure (normal pressure return step) ).

  Then, the lid 6 is lowered by the boat elevator 127 to unload the semiconductor wafer W and collect the semiconductor wafer W from the wafer boat 9 (wafer discharge process).

  Next, the inside of the reaction tube 2 is set to a predetermined temperature, for example, 630 ° C. as shown in FIG. In addition, a predetermined amount of nitrogen is supplied into the reaction tube 2 from the processing gas supply tube 21 and the like, and the gas in the reaction tube 2 is exhausted, so that the reaction tube 2 has a predetermined pressure, for example, as shown in FIG. Thus, it is set to 1064 Pa (8 Torr) (standby process).

  The temperature in the reaction tube 2 is preferably 450 ° C to 800 ° C. By setting it in this range, the surface of the adhering material adhering to the inside of the apparatus can be easily carbon-terminated, and corrosion and particle generation can be suppressed.

  The pressure in the reaction tube 2 is preferably 0.133 Pa (0.001 Torr) to 1.33 kPa (10 Torr). By setting the pressure in such a range, the surface of the deposit attached to the inside of the apparatus can be easily carbon-terminated, and corrosion and particle generation can be suppressed. The pressure in the reaction tube 2 is more preferably 13.3 Pa (0.1 Torr) to 1.33 kPa (10 Torr), and most preferably 133 Pa (1 Torr) to 1064 Pa (8 Torr). This is because the pressure in the reaction tube 2 can be easily controlled by setting the pressure within this range.

Subsequently, as shown in FIG. 3F, 1 slm of ethylene (C ₂ H ₄ ) is supplied into the reaction tube 2 from the processing gas supply tube 21 or the like (carbon purge step).

  The supply amount of ethylene is preferably 10 sccm to 10 slm. This is because if it is less than 10 sccm, the surface of the deposit attached inside the apparatus may not be sufficiently carbon-terminated, and if it is more than 10 slm, ethylene that does not contribute to the reaction may increase. The supply amount of ethylene is more preferably 0.1 slm to 10 slm, and most preferably 0.1 slm to 5 slm. This is because the carbon termination treatment on the surface of the deposit is promoted by setting the amount within this range.

  When ethylene is supplied into the reaction tube 2, the surface of the deposit attached inside the apparatus is terminated with carbon. This makes it difficult for the inside of the apparatus to corrode. Further, since the surface of the deposit is carbon-terminated, the deposit is difficult to peel from the inside of the apparatus, and the generation of particles can be suppressed. Further, the outgas generated from the silicon nitride film remaining inside the device is terminated with carbon and is difficult to adhere to the inside of the device.

  When the carbon purge process is completed, the supply of ethylene from the processing gas supply pipe 21 and the like is stopped. Then, the gas in the reaction tube 2 is discharged, and a predetermined amount of nitrogen is supplied from the processing gas supply tube 21 into the reaction tube 2 to react the gas in the reaction tube 2 as shown in FIG. It discharges out of the pipe 2 (purge, vacuum process), and this process is completed. Then, the above-described silicon nitride film forming step can be performed again.

  As described above, the carbon purge process is performed between the process of forming the silicon nitride film on the semiconductor wafer W and the process of forming the silicon nitride film on the new semiconductor wafer W, so that it can be applied from the inside of the apparatus. The kimono becomes difficult to peel off, and the generation of particles can be suppressed. In addition, the inside of the apparatus is hardly corroded. Furthermore, the outgas generated from the silicon nitride film remaining in the apparatus becomes difficult to adhere to the inside of the apparatus. As a result, corrosion inside the apparatus and generation of particles can be suppressed and productivity can be improved.

  Next, in order to confirm the effect of the present invention, the inside of the reaction tube 2 after the silicon nitride film is formed according to the above embodiment is etched for 10 seconds using BHF (Buffered Hydrogen Fluoride). The etching amount was measured (Example 1). Etching when the inside of the reaction tube 2 is etched for 10 seconds using BHF after the silicon nitride film is formed by the same method except that the pressure in the reaction tube 2 is set to 133 Pa (1 Torr) in the carbon purge step. The amount was measured (Example 2). For comparison, the etching amount was also measured in the same manner when nitrogen gas was used as the carbon purge gas (Comparative Example 1) and when the carbon purge process was not performed (Comparative Example 2). The results are shown in FIG.

  As shown in FIG. 4, it was confirmed that the etching amount can be reduced by performing the carbon purge process. In particular, it was confirmed that the etching amount was greatly reduced by setting the pressure in the reaction tube 2 to 1064 Pa (8 Torr). This is because the surface of the deposit attached to the inside of the apparatus is carbon-terminated and the deposit is difficult to peel off from the inside of the apparatus. Further, this is because the outgas generated from the silicon nitride film remaining inside the device is carbon-terminated and is difficult to adhere to the inside of the device.

  As described above, according to the present embodiment, the carbon purge process is performed after the nitride film forming process, whereby the surface of the deposit attached to the inside of the apparatus is carbon-terminated, and the deposit is not easily peeled off from the inside of the apparatus. Become. Further, the outgas generated from the silicon nitride film remaining inside the device is terminated with carbon and is difficult to adhere to the inside of the device. As a result, corrosion inside the apparatus and generation of particles can be suppressed and productivity can be improved.

  In addition, this invention is not restricted to said embodiment, A various deformation | transformation and application are possible. Hereinafter, other embodiments applicable to the present invention will be described.

In the above embodiment, the present invention has been described by taking the case of forming a silicon nitride film as an example. For example, a silicon oxide film (SiO ₂ film), a silicon nitride film containing boron (SiBN film), silicon, boron, and carbon It is possible to apply to various thin films such as a film containing nitrogen and nitrogen (SiBCN film).

  In the above embodiment, the present invention has been described by taking as an example the case where the carbon purge step is performed between the steps of forming the silicon nitride film, but the present invention is limited to the case where the same type of thin film is formed a plurality of times. For example, the carbon purge process may be performed in a process of forming different types of thin films such that a carbon purge process is performed after the SiBN film is formed and then a silicon nitride film is formed.

  In the above embodiment, the present invention has been described by taking DCS as the Si source and ammonia as the nitriding gas as an example. However, the Si source and the nitriding gas may be any organic source gas capable of forming a silicon nitride film, Various gases can be used.

  In the above-described embodiment, the present invention has been described by taking as an example the case where a silicon nitride film is formed on the semiconductor wafer W by executing 100 cycles. Good. Further, the number of cycles may be increased as in 200 cycles. Also in this case, a silicon nitride film having a desired thickness can be formed by adjusting the supply amount of Si source and ammonia, for example, according to the number of cycles.

  In the above embodiment, the present invention has been described by taking as an example the case where a silicon nitride film is formed on the semiconductor wafer W using the ALD method. However, the present invention is not limited to the case where the ALD method is used, A silicon nitride film may be formed on the semiconductor wafer W by using the CVD method.

  In the above embodiment, the present invention has been described by taking as an example the case where nitrogen as a diluent gas is supplied when the source gas and the nitriding gas are supplied. However, it is not necessary to supply nitrogen when the source gas and the nitriding gas are supplied. However, it is preferable to include a dilution gas because it is easy to set the processing time by including nitrogen as a dilution gas. The diluent gas is preferably an inert gas, and in addition to nitrogen, for example, helium (He), neon (Ne), argon (Ar), krypton (Kr), and xenon (Xe) can be applied.

  In the present embodiment, the present invention has been described as an example of a single-pipe structure batch processing apparatus as the thin film forming apparatus. For example, the present invention is applied to a double-pipe single-pipe batch processing apparatus. It is also possible to apply. Further, the present invention can be applied to a batch type horizontal processing apparatus or a single wafer processing apparatus. Further, the object to be processed is not limited to the semiconductor wafer W, and may be a glass substrate for LCD (Liquid Crystal Display), for example.

  The control unit 100 according to the embodiment of the present invention can be realized using a normal computer system, not a dedicated system. For example, the above-described processing is executed by installing the program from a recording medium (such as a flexible disk or a CD-ROM (Compact Disc Read Only Memory)) storing the program for executing the above-described processing in a general-purpose computer. The control unit 100 can be configured.

  The means for supplying these programs is arbitrary. In addition to being able to be supplied via a predetermined recording medium as described above, for example, it may be supplied via a communication line, a communication network, a communication system, or the like. In this case, for example, the program may be posted on a bulletin board (BBS: Bulletin Board System) of a communication network and provided via the network. Then, the above-described processing can be executed by starting the program thus provided and executing it in the same manner as other application programs under the control of an OS (Operating System).

  The present invention is useful for a thin film forming method such as a silicon nitride film and a silicon oxide film, and a thin film forming apparatus.

DESCRIPTION OF SYMBOLS 1 Heat processing apparatus 2 Reaction pipe 3 Manifold 4 Exhaust pipe 5 Pressure adjustment part 6 Cover body 8 Heat insulation cylinder 9 Wafer boat 10 Heater part 11-15 Heater 21-23 Process gas supply pipe 24-26 Flow volume adjustment part 100 Control part 111 Recipe memory | storage Part 112 ROM
113 RAM
114 I / O port 115 CPU
116 Bus 121 Operation panel 122 Temperature sensor 123 Pressure gauge 124 MFC
125 Valve control unit 126 Vacuum pump 127 Boat elevator 128 Heater controller W Semiconductor wafer

Claims (6)

A housing step of housing the object to be processed in the reaction chamber;
A thin film forming step of forming a thin film on the target object accommodated in the reaction chamber;
A thin film forming method that repeats an unloading step of unloading the object on which the thin film is formed out of the reaction chamber,
Between the unloading step and the containing step, a gas containing carbon is supplied into the reaction chamber, and the surface of the deposit attached to the inside of the apparatus is terminated with carbon, and is generated from the thin film and remains inside the apparatus. A thin film forming method comprising a carbon purging step for terminating a gas with carbon.   2. The thin film forming method according to claim 1, wherein, in the carbon purge step, ethylene, propylene, or acetylene is used as a gas containing carbon supplied into the reaction chamber.   3. The thin film forming method according to claim 1, wherein the thin film is a silicon nitride film, a silicon oxide film, a silicon nitride film containing boron, or a film containing silicon, boron, carbon, and nitrogen. .   4. The thin film forming method according to claim 1, wherein, in the carbon purge step, the pressure in the reaction chamber is set to 13.3 Pa to 1.33 kPa. 5.   4. The thin film forming method according to claim 1, wherein in the carbon purge step, a gas containing carbon is supplied into the reaction chamber in an amount of 0.1 slm to 10 slm. A reaction chamber for accommodating a workpiece,
A film forming gas supply means for supplying a film forming gas into the reaction chamber;
A carbon gas supply means for supplying a gas containing carbon into the reaction chamber;
Control means for controlling each part of the apparatus,
The control means includes
The object to be processed is accommodated in the reaction chamber, the film forming gas supply means is controlled to form a thin film on the object to be processed accommodated in the reaction chamber, and the object to be processed on which the thin film is formed is reacted with the reaction. Repeat the process of taking it out of the room,
A gas containing carbon in the reaction chamber is controlled by controlling the carbon gas supply means while the object to be processed is accommodated in the reaction chamber after unloading the object to be processed in which the thin film is formed. A thin film forming apparatus characterized in that the surface of deposits supplied and adhered inside the apparatus is carbon-terminated, and gas generated from the thin film and remaining in the apparatus is carbon-terminated.

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