JP5193527B2 - Silicon oxide film forming method, silicon oxide film forming apparatus, and program - Google Patents

Description

  The present invention relates to a silicon oxide film forming method, a silicon oxide film forming apparatus, and a program.

  In recent years, when a silicon oxide film is formed on a semiconductor wafer, it is required to perform the treatment at a low temperature. For example, a method of forming a silicon oxide film using plasma has been studied. However, when the silicon oxide film is formed by such a method, there is a problem that the step coverage is deteriorated, and an ALD (Atomic Layer Deposition) method capable of forming a thin film with good step coverage at a low temperature has begun to be adopted. Yes.

Various methods have been proposed for forming a thin film using such an ALD method. 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

  Incidentally, the silicon oxide film is required to further improve the film quality. Therefore, a method capable of forming a high-quality silicon oxide film at a low temperature is demanded.

  The present invention has been made in view of the above problems, and provides a silicon oxide film forming method, a silicon oxide film forming apparatus, and a program capable of forming a high-quality silicon oxide film at a low temperature. Objective.

In order to achieve the above object, a method for forming a silicon oxide film according to the first aspect of the present invention includes:
An adsorption step of supplying monovalent aminosilane into a reaction chamber in which the object to be treated is accommodated, and adsorbing silicon to the object to be treated;
A silicon oxide film forming step of supplying an activated oxidizing gas to the silicon adsorbed in the adsorption step, oxidizing the silicon, and forming a silicon oxide film on the object to be processed;
The adsorption step and the silicon oxide film formation step are repeated a plurality of times,
The reaction chamber is set to room temperature to 700 ° C.,
In the silicon oxide film forming step, oxygen, ozone, or water vapor is used as the oxidizing gas,
In the adsorption step, the reaction chamber is set to 0.133 Pa to 13.3 kPa, the monovalent aminosilane is supplied into the reaction chamber at 10 sccm to 10 slm , and SiH ₃ (NHC (CH ₃ ) _{3), or} Ru with _{SiH 3 (N (CH 3)} 2), characterized in that.

In the silicon oxide film forming step, for example, the reaction chamber is set to 0.133 Pa to 13.3 kPa.
In the silicon oxide film formation step, for example, an oxidizing gas is supplied to the reaction chamber at 1 sccm to 10 slm.

  In the silicon oxide film forming step, for example, an oxidizing gas is supplied to a plasma generating chamber set to 0.133 Pa to 13.3 kPa to form oxidizing gas radicals, and the oxidizing gas radicals are formed into the plasma generating chamber. To the reaction chamber.

  In the silicon oxide film forming step, for example, ozone is supplied into the reaction chamber set at 200 ° C. to 600 ° C. to activate the ozone, and the activated ozone is supplied to the adsorbed silicon. Silicon is oxidized to form a silicon oxide film on the object to be processed.

An apparatus for forming a silicon oxide film according to a second aspect of the present invention provides:
A reaction chamber for accommodating a workpiece,
An aminosilane supply means for supplying monovalent aminosilane into the reaction chamber;
An oxidizing gas supply means for supplying an activated oxidizing gas to the object to be processed;
Control means for controlling each part of the apparatus,
The control means includes
By controlling the aminosilane supply means, the reaction chamber is set to 0.133 Pa to 13.3 kPa, the monovalent aminosilane is supplied to the reaction chamber at 10 sccm to 10 slm, and silicon is adsorbed on the object to be processed.
Controlling the oxidizing gas supply means to supply an activated oxidizing gas to the adsorbed silicon, oxidize the silicon, and form a silicon oxide film on the object to be processed;
Repeat the process multiple times,
The reaction chamber is set to room temperature to 700 ° C.,
The oxidizing gas is oxygen, ozone or, Ri steam der,
The monovalent _{aminosilane, SiH 3 (NHC (CH 3} ) 3), _{or, SiH 3 (N (CH 3} ) 2) Ru der, characterized in that.

The program according to the third aspect of the present invention is:
Computer
An aminosilane supply means for supplying monovalent aminosilane into the reaction chamber containing the object to be treated;
An oxidizing gas supply means for supplying an activated oxidizing gas to the object to be processed;
By controlling the aminosilane supply means, the reaction chamber is set to 0.133 Pa to 13.3 kPa, the monovalent aminosilane is supplied to the reaction chamber at 10 sccm to 10 slm, and silicon is adsorbed on the object to be processed. Control that repeats the process a plurality of times by controlling the oxidizing gas supply means, supplying activated oxidizing gas to the adsorbed silicon, oxidizing the silicon, and forming a silicon oxide film on the object to be processed means,
Function as
The reaction chamber is set to room temperature to 700 ° C.,
The oxidizing gas is oxygen, ozone or, Ri steam der,
The monovalent _{aminosilane, SiH 3 (NHC (CH 3} ) 3), _{or, SiH 3 (N (CH 3} ) 2) Ru der, characterized in that.

  According to the present invention, a high-quality silicon oxide film can be formed at a low temperature.

  Hereinafter, a silicon oxide film forming method, a silicon oxide film forming apparatus, and a program according to embodiments of the present invention will be described. In this embodiment, an example in which a silicon oxide film is formed using an MLD (Molecular Layer Deposition) method will be described. Further, a case where a batch type vertical processing apparatus is used as the silicon oxide film forming apparatus of the present invention will be described as an example. FIG. 1 shows the configuration of the processing apparatus of the present embodiment. FIG. 2 shows a cross-sectional configuration of the processing apparatus of the present embodiment.

  As shown in FIG. 1, the processing apparatus 1 includes a reaction tube 2 with a ceiling and a substantially cylindrical shape whose longitudinal direction is directed in the vertical direction. The reaction tube 2 is made of a material excellent in heat resistance and corrosion resistance, for example, quartz.

  On one side of the reaction tube 2, an exhaust part 3 for exhausting the gas in the reaction tube 2 is arranged. The exhaust part 3 is formed so as to extend upward along the reaction tube 2, and communicates with the reaction tube 2 through an opening provided on a side wall of the reaction tube 2 (not shown). The upper end of the exhaust part 3 is connected to an exhaust port 4 arranged at the upper part of the reaction tube 2. An exhaust pipe (not shown) is connected to the exhaust port 4, and a pressure adjustment mechanism such as a valve (not shown) and a vacuum pump 127 described later is provided on the exhaust pipe. By this pressure adjusting mechanism, the gas in the reaction tube 2 is exhausted to the exhaust tube through the opening, the exhaust part 3 and the exhaust port 4, and the inside of the reaction tube 2 is controlled to a desired pressure (degree of vacuum).

  A lid 5 is disposed below the reaction tube 2. The lid 5 is made of a material excellent in heat resistance and corrosion resistance, for example, quartz. The lid 5 is configured to be movable up and down by a boat elevator 128 described later. When the lid 5 is raised by the boat elevator 128, the lower side (furnace port portion) of the reaction tube 2 is closed, and when the lid 5 is lowered by the boat elevator 128, the lower side (furnace port portion) of the reaction tube 2. Is opened.

  A wafer boat 6 is placed on the lid 5. The wafer boat 6 is made of, for example, quartz. The wafer boat 6 is configured to accommodate a plurality of semiconductor wafers W at predetermined intervals in the vertical direction. In addition, on the upper part of the lid 5, a heat insulating cylinder for preventing the temperature in the reaction tube 2 from decreasing from the furnace port portion of the reaction tube 2 and a wafer boat 6 for housing the semiconductor wafers W are rotatably mounted. A rotary table may be provided, and the wafer boat 6 may be placed thereon. In these cases, it becomes easy to control the semiconductor wafers W accommodated in the wafer boat 6 to a uniform temperature.

  Around the reaction tube 2, for example, a heating heater 7 made of a resistance heating element is provided so as to surround the reaction tube 2. The inside of the reaction tube 2 is heated to a predetermined temperature by the temperature raising heater 7, and as a result, the semiconductor wafer W accommodated in the reaction tube 2 is heated to a predetermined temperature.

Processing gas supply pipes 8 and 9 for supplying a processing gas into the reaction tube 2 are inserted in side surfaces near the lower end of the reaction tube 2. Examples of the processing gas include source gas, oxidizing gas, and dilution gas. The source gas is a Si source made of monovalent aminosilane that adsorbs the source (Si) to the object to be processed, and is used in an adsorption step described later. The oxidizing gas is a gas that oxidizes the adsorbed source (Si) and is used in an oxidation step described later. In this example, oxygen (O ₂ ) is used as the oxidizing gas. The dilution gas is a gas for diluting the processing gas, and nitrogen (N ₂ ) is used in this example.

Of these process gases, an oxidizing gas is supplied into the reaction tube 2 via the process gas supply pipe 8. The processing gas supply pipe 8 is inserted into a plasma generator 10 which will be described later. For this reason, the oxidizing gas supplied from the processing gas supply pipe 8 is plasma-excited (activated). The source gas and the dilution gas are supplied into the reaction tube 2 through the processing gas supply tube 9. A purge gas (for example, nitrogen (N ₂ )) is also supplied into the reaction tube 2 through the processing gas supply tube 9. The purge gas may be separately supplied into the reaction tube 2 via a purge gas supply tube. The processing gas supply pipe 9 is disposed on the inner wall of the reaction pipe 2 as shown in FIG. For this reason, the source gas and the purge gas supplied from the processing gas supply pipe 9 are not plasma-excited (activated). For example, a dispersion injector is used as the processing gas supply pipe 9.

  Each processing gas supply pipe 8, 9 is provided with a supply hole at a predetermined interval in the vertical direction, and the processing gas is supplied into the reaction tube 2 from the supply hole. For this reason, as shown by the arrows in FIG. 1, the processing gas is supplied into the reaction tube 2 from a plurality of locations in the vertical direction. The processing gas supply pipes 8 and 9 are connected to a processing gas supply source (not shown) via a mass flow controller (MFC) 125 described later. In FIG. 1, only a processing gas supply pipe 8 (a processing gas supply pipe for supplying an oxidizing gas in the present embodiment) for supplying a processing gas for performing a plasma processing described later is illustrated. In FIG. 2, a processing gas supply pipe 8 that supplies an oxidizing gas and a processing gas supply pipe 9 that supplies a processing gas that does not perform plasma processing, which will be described later (in this embodiment, a process for supplying a source gas and a purge gas). Gas supply pipe).

On the other side of the reaction tube 2, that is, on the opposite side of one side of the reaction tube 2 where the exhaust unit 3 is disposed, a plasma generation unit 10 is provided. The plasma generation unit 10 includes a pair of electrodes 11 and the like. A processing gas supply pipe 8 is inserted between the pair of electrodes 11 in the plasma generator 10. The pair of electrodes 11 is connected to a high-frequency power source, a matching unit, etc. (not shown). Then, high frequency power is applied between the pair of electrodes 11 from a high frequency power supply via a matching unit, thereby plasma excitation (activation) of the processing gas supplied between the pair of electrodes 11 and oxygen radicals (O ₂ ^* ) Etc. Oxygen radicals (O ₂ ^* ) and the like generated in this way are supplied from the plasma generator 10 into the reaction tube 2.

  In the reaction tube 2, a plurality of temperature sensors 122 that measure the temperature in the reaction tube 2, for example, a thermocouple and a pressure gauge 123 that measures the pressure in the reaction tube 2 are arranged. .

  In addition, the processing device 1 includes a control unit 100 that controls each unit of the device. FIG. 3 shows the configuration of the control unit 100. As shown in FIG. 3, the control unit 100 includes an operation panel 121, a temperature sensor (group) 122, a pressure gauge (group) 123, a heater controller 124, an MFC 125, a valve control unit 126, a vacuum pump 127, a boat elevator 128, A plasma control unit 129 and the like are connected.

  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 (group) 122 measures the temperature of each part such as the inside of the reaction tube 2 and the exhaust pipe, and notifies the control unit 100 of the measured value.
The pressure gauge (group) 123 measures the pressure of each part such as the inside of the reaction tube 2 and the exhaust pipe, and notifies the control unit 100 of the measured value.

  The heater controller 124 is for individually controlling the temperature raising heater 7, and in response to an instruction from the control unit 100, energizes the temperature raising heater 7 to heat them. The power consumption of the heater 7 is individually measured and notified to the control unit 100.

  The MFC 125 is arranged in each pipe such as the processing gas supply pipes 8 and 9 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. The control unit 100 is notified.

The valve control unit 126 is arranged in each pipe, and controls the opening degree of the valve arranged in each pipe to a value instructed by the control unit 100.
The vacuum pump 127 is connected to the exhaust pipe and exhausts the gas in the reaction tube 2.

  The boat elevator 128 raises the lid 5 to load the wafer boat 6 (semiconductor wafer W) into the reaction tube 2 and lowers the lid 5 to react the wafer boat 6 (semiconductor wafer W). Unload from within tube 2.

The plasma control unit 129 is for controlling the plasma generation unit 10. In response to an instruction from the control unit 100, the plasma control unit 129 controls the plasma generation unit 10 and is supplied into the plasma generation unit 10. Oxygen is activated to generate oxygen radicals (O ₂ ^* ) and the like.

  The control unit 100 includes a recipe storage unit 111, a ROM 112, a RAM 113, an I / O port 114, a CPU 115, and a bus 116 that interconnects them.

  The recipe storage unit 111 stores a setup recipe and a plurality of process recipes. At the beginning of manufacturing the processing 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 amount of the processing gas are defined.

The ROM 112 is a recording medium that includes an EEPROM, 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, temperature sensor 122, pressure gauge 123, heater controller 124, MFC 125, valve controller 126, vacuum pump 127, boat elevator 128, plasma controller 129, etc. Control the input and output of.

A CPU (Central Processing Unit) 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 processing 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 (group) 122, the pressure gauge (group) 123, the MFC 125, and the like to measure the temperature, pressure, flow rate, and the like of each part in the reaction tube 2 and the exhaust tube, and based on the measurement data, Control signals and the like are output to the heater controller 124, the MFC 125, the valve control unit 126, the vacuum pump 127, and the like, and the above-described units are controlled to follow the process recipe.
The bus 116 transmits information between the units.

  Next, a method for forming a silicon oxide film using the processing apparatus 1 configured as described above will be described with reference to a recipe (time sequence) shown in FIG. In the silicon oxide film forming method of the present embodiment, a silicon oxide film is formed on the semiconductor wafer W by MLD (Molecular Layer Deposition).

  As shown in FIG. 4, the present embodiment includes an adsorption step for adsorbing silicon (Si) on the surface of the semiconductor wafer W, and an oxidation step for oxidizing the adsorbed Si. One cycle of the law is shown. Further, as shown in FIG. 4, in the present embodiment, oxygen is used as the oxidizing gas and nitrogen is used as the diluent gas. A desired silicon oxide film 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 unit constituting the processing 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 determined by the control unit 100 (CPU 115) by the heater controller 124 (heating heater 7) and the MFC 125 (processing gas supply pipe 8). 9), by controlling the valve controller 126, the vacuum pump 127, the plasma controller 129 (plasma generator 10), etc., the conditions are set according to the recipe shown in FIG.

  First, a semiconductor wafer W as an object to be processed is accommodated (loaded) in the reaction tube 2. Specifically, the inside of the reaction tube 2 is maintained at a predetermined load temperature by the heater 7 for raising temperature, and a predetermined amount of nitrogen is supplied into the reaction tube 2. In addition, the wafer boat 6 containing the semiconductor wafers W is placed on the lid 5. Then, the lid 5 is raised by the boat elevator 128, and the semiconductor wafer W (wafer boat 6) is loaded into the reaction tube 2.

  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, the temperature inside the reaction tube 2 is set to a predetermined temperature, for example, 400 ° C. as shown in FIG. In addition, a predetermined amount of nitrogen is supplied from the processing gas supply pipe 9 into the reaction tube 2, and the gas in the reaction tube 2 is discharged, so that the reaction tube 2 has a predetermined pressure, for example, as shown in FIG. And 66.5 Pa (0.5 Torr). Then, a predetermined amount of Si source is supplied from the processing gas supply pipe 9, for example, 0.3 slm as shown in FIG. 4 (d), and a predetermined amount of nitrogen inside the reaction tube 2 as shown in FIG. 4 (c). (Flow process).

  Here, the temperature in the reaction tube 2 is preferably room temperature (RT) to 700 ° C. If the temperature is lower than room temperature, a silicon oxide film may not be formed. If the temperature in the reaction tube 2 is higher than 700 ° C., the quality and uniformity of the film thickness of the formed silicon oxide film deteriorate. This is because there is a risk that it may occur. The temperature in the reaction tube 2 is more preferably RT to 700 ° C, and further preferably RT to 500 ° C. This is because, by setting the temperature within such a range, the film quality and film thickness uniformity of the formed silicon oxide film can be further improved.

  In the method for forming the silicon oxide film, it is preferable that the temperature in the reaction tube 2 is not changed in the film forming sequence. For this reason, in this embodiment, as will be described later, the temperature in the reaction tube 2 is not changed even in the oxidation step, and is set to 400 ° C.

  The supply amount of the Si source 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 the Si source 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.

  FIG. 5 schematically shows the reaction on the surface of the semiconductor wafer W. The Si source supplied into the reaction tube 2 is heated and activated in the reaction tube 2. For this reason, when the Si source is supplied into the reaction tube 2, the surface of the semiconductor wafer W reacts with the activated Si as shown in FIG. 5B from the state shown in FIG. Si is adsorbed on the surface of the semiconductor wafer W.

  Here, since the Si source is monovalent aminosilane, nitrogen (N) is not included in the adsorbate adsorbed in the adsorption step, and nitrogen is included in the silicon oxide film formed by the method of the present invention. It becomes difficult to be. For this reason, a high-quality silicon oxide film can be formed. Further, since the Si source is monovalent aminosilane, structural failure is unlikely to occur during Si adsorption, and adsorption of other molecules is difficult to be prevented. For this reason, the adsorption speed is not slowed, and productivity does not decrease.

  When a predetermined amount of Si is adsorbed on the surface of the semiconductor wafer W, supply of Si source and nitrogen from the processing gas supply pipe 9 is stopped. Then, the gas in the reaction tube 2 is discharged, and for example, a predetermined amount of nitrogen is supplied from the processing gas supply tube 9 into the reaction tube 2 to discharge the gas in the reaction tube 2 to the outside of the reaction tube 2 (purge). , Vacuum process).

  Subsequently, an oxidation step for oxidizing the surface of the semiconductor wafer W is performed. The oxidation step is a process of oxidizing the adsorbed Si by supplying an oxidizing gas onto the semiconductor wafer W on which Si is adsorbed. In the present embodiment, Si adsorbed by supplying oxygen (oxygen radicals) onto the semiconductor wafer W is oxidized.

In the oxidation step, the inside of the reaction tube 2 is set to a predetermined temperature, for example, 400 ° C. as shown in FIG. In addition, a predetermined amount of nitrogen is supplied from the processing gas supply pipe 9 into the reaction tube 2, and the gas in the reaction tube 2 is discharged, so that the reaction tube 2 has a predetermined pressure, for example, as shown in FIG. And 66.5 Pa (0.5 Torr). Then, as shown in FIG. 4G, high-frequency power is applied between the electrodes 11 from a high-frequency power source (not shown) via a matching unit (RF: ON), and oxygen is supplied from the processing gas supply pipe 8 to a predetermined amount, for example, As shown in FIG. 4E, 1 slm is supplied between the pair of electrodes 11 (inside the plasma generator 10). Oxygen supplied between the pair of electrodes 11 is plasma-excited (activated) to generate oxygen radicals (O ^* ). The oxygen radicals generated in this way are supplied from the plasma generation unit 10 into the reaction tube 2. Further, as shown in FIG. 4C, a predetermined amount of nitrogen as a dilution gas is supplied from the processing gas supply pipe 9 into the reaction pipe 2 (flow process).

  Here, the supply amount of oxygen is preferably 1 sccm to 10 slm. This is because, within this range, plasma can be generated without problems and oxygen radicals sufficient to form a silicon oxide film can be supplied. More preferably, the supply amount of oxygen is 0.5 slm to 5 slm. This is because the plasma can be generated stably by setting it in such a range.

  The RF power is preferably 10 W to 1500 W. This is because if it is less than 10 W, oxygen radicals are hardly generated, and if it exceeds 1500 W, the quartz wall constituting the plasma generation unit 10 may be damaged. The RF power is more preferably 50 W to 500 W. This is because, within this range, oxygen radicals can be generated efficiently.

  The pressure in the reaction tube 2 is preferably 0.133 Pa (0.001 Torr) to 13.3 kPa (100 Torr). By setting the pressure in such a range, oxygen radicals are likely to be generated, and the mean free path of oxygen radicals in the space where the semiconductor wafer W is placed increases. 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 pressure in the plasma generating unit 10 is preferably 0.133 Pa (0.001 Torr) to 13.3 kPa (100 Torr), and more preferably 70 Pa (0.53 Torr) to 400 Pa (3 Torr). This is because by setting the pressure within such a range, plasma can be generated without problems and oxygen radicals sufficient to form a silicon oxide film can be supplied.

  When oxygen radicals are supplied into the reaction tube 2, Si adsorbed on the semiconductor wafer W is oxidized as shown in FIG. 5D from the state shown in FIG. A silicon oxide film is formed. When a desired silicon oxide film is formed on the semiconductor wafer W, the supply of oxygen from the processing gas supply pipe 8 is stopped and the application of high-frequency power from a high-frequency power source (not shown) is stopped. Further, the supply of nitrogen from the processing gas supply pipe 9 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 9 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).

  As a result, one cycle of the MLD method including the adsorption step and the oxidation step is completed.

  Subsequently, one cycle of the MLD method starting from the adsorption step is started again. Then, this cycle is repeated a predetermined number of times. As a result, Si source is supplied to the surface of the semiconductor wafer W as shown in FIG. 5E, Si is adsorbed as shown in FIG. 5F, and the adsorbed Si is oxidized to form silicon. An oxide film is formed. As a result, a silicon oxide film having a desired thickness is formed on the semiconductor wafer W.

  When a silicon oxide film having a desired thickness is formed on the semiconductor wafer W, the semiconductor wafer W is unloaded. Specifically, a predetermined amount of nitrogen is supplied from the process gas supply pipe 9 into the reaction tube 2 to return the pressure in the reaction tube 2 to normal pressure, and the temperature inside the reaction tube 2 is set to a predetermined level by the heating heater 7. Maintain temperature. Then, the semiconductor wafer W is unloaded by lowering the lid 5 by the boat elevator 128.

  Next, the composition of the silicon oxide film formed by such a method was confirmed using an X-ray photoelectron spectrometer (XPS). As a result, it was confirmed that the formed silicon oxide film did not contain nitrogen. For this reason, it was confirmed that a high-quality silicon oxide film was formed at a low temperature.

Further, the film formation rate (cycle rate) per cycle of the formed silicon oxide film was obtained. For comparison, divalent aminosilane (BTBAS: SiH ₂ (NHC (CH ₃ ) ₃ ) ₂ ), trivalent aminosilane (3DMAS: SiH (N (CH ₃ ) ₂ ) ₃ ) is used as a source gas. Similarly, the cycle rate was obtained. FIG. 6 shows the cycle rate of divalent aminosilane and monovalent aminosilane when the cycle rate when trivalent aminosilane is used as the source gas is 1.

  As shown in FIG. 6, it was confirmed that the cycle rate was improved by using monovalent aminosilane as the source gas. This is thought to be because structural failure is unlikely to occur during Si adsorption, and it is difficult to prevent adsorption of other molecules.

  As described above, according to the present embodiment, by repeating a cycle including an adsorption step for adsorbing Si using monovalent aminosilane and an oxidation step for oxidizing the adsorbed Si, a semiconductor is obtained. Since the silicon oxide film is formed on the wafer W, a high-quality silicon oxide film that does not contain nitrogen can be formed in the film. For this reason, a high-quality silicon oxide film can be formed at a low temperature.

  In addition, according to the present embodiment, since monovalent aminosilane is used as the source gas, structural failure is unlikely to occur during Si adsorption, and adsorption of other molecules is unlikely to be hindered. For this reason, the adsorption speed is not slowed, and productivity does not decrease.

  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 as an example the case where oxygen radicals are generated by plasma. However, the present invention only needs to be able to activate an oxidizing gas. For example, a catalyst, UV, Heat, magnetic force or the like may be used. For example, when the oxidizing gas is activated by heat, a heat treatment apparatus as shown in FIG. 7 can be used. For example, when such a heat treatment apparatus is used, oxygen can be activated by introducing oxygen into the reaction tube 2 heated to a predetermined temperature. The temperature in the reaction tube 2 may be any temperature that can activate the supplied oxygen, and is preferably about 550 ° C., for example. The pressure in the reaction tube 2 is preferably about 133 Pa (1 Torr), and the oxygen supply amount is preferably 100 sccm to 1 slm.

In the above-described embodiment, the present invention has been described by taking as an example the case where oxygen is used as the oxidizing gas. However, the oxidizing gas only needs to be capable of oxidizing Si adsorbed on the semiconductor wafer W. For example, ozone ( O ₃ ), water vapor (H ₂ O), or the like may be used. For example, when ozone is used as the oxidizing gas, the temperature in the reaction tube 2 is 200 ° C. to 600 ° C., the pressure is 133 Pa (1 Torr), the ozone is 10 slm, and O ₃ / O ₂ is about 250 g / Nm ^3. preferable.

As the Si source of the above embodiment, various aminosilanes can be used as long as they are monovalent aminosilanes. Examples of the monovalent aminosilane include SiH ₃ (NHC (CH ₃ ) ₃ ) and SiH ₃ (N (CH ₃ ) ₂ ).

  In the above embodiment, the present invention has been described by taking as an example the case where a silicon oxide film is formed on the semiconductor wafer W by executing 100 cycles. However, even if the number of cycles is reduced, for example, 50 cycles. Good. Further, the number of cycles may be increased as in 200 cycles. Also in this case, a silicon oxide film having a desired thickness can be formed by adjusting, for example, the supply amount of Si source and oxygen, RF power, and the like according to the number of cycles.

  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 supplying the processing gas, but it is not necessary to supply nitrogen when supplying the processing gas. 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 above embodiment, the present invention is described by taking as an example the case where the processing gas supply pipe 8 for supplying the processing gas for performing the plasma processing and the processing gas supply pipe 9 for supplying the processing gas for which the plasma processing is not performed are provided. However, for example, a processing gas supply pipe may be provided for each type of processing gas. Further, a plurality of processing gas supply pipes 8 and 9 may be inserted in the side surface near the lower end of the reaction tube 2 so that the same gas is supplied from the plurality. In this case, the processing gas is supplied into the reaction tube 2 from the plurality of processing gas supply pipes 8 and 9, and the processing gas can be supplied more uniformly into the reaction tube 2.

  In the present embodiment, the present invention has been described by taking the case of a single-pipe structure batch processing apparatus as the processing apparatus 1 as an example, but for example, the reaction tube 2 is a double tube composed of an inner tube and an outer tube. It is also possible to apply the present invention to a batch type vertical processing apparatus having a tube structure. 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, 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 control unit 100 that executes the above-described processing is configured by installing the program from a recording medium (such as a flexible disk or a CD-ROM) that stores the program for executing the above-described processing in a general-purpose computer. be able to.

  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) of a communication network and provided by superimposing it on a carrier wave 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 the OS.

It is a figure which shows the processing apparatus of embodiment of this invention. It is a figure which shows the cross-sectional structure of the processing apparatus of FIG. It is a figure which shows the structure of the control part of FIG. It is a figure explaining the formation method of a silicon oxide film. It is a figure for demonstrating reaction of the semiconductor wafer surface. It is a figure which shows the cycle rate at the time of changing source gas. It is a figure which shows the processing apparatus of other embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Processing apparatus 2 Reaction tube 3 Exhaust part 4 Exhaust port 5 Cover body 6 Wafer boat 7 Heating heater 8, 9 Process gas supply pipe 10 Plasma generation part 11 Electrode 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 Heater controller 125 MFC
126 Valve control unit 127 Vacuum pump 128 Boat elevator 129 Plasma control unit W Semiconductor wafer

Claims (7)

An adsorption step of supplying monovalent aminosilane into a reaction chamber in which the object to be treated is accommodated, and adsorbing silicon to the object to be treated;
A silicon oxide film forming step of supplying an activated oxidizing gas to the silicon adsorbed in the adsorption step, oxidizing the silicon, and forming a silicon oxide film on the object to be processed;
The adsorption step and the silicon oxide film formation step are repeated a plurality of times,
The reaction chamber is set to room temperature to 700 ° C.,
In the silicon oxide film forming step, oxygen, ozone, or water vapor is used as the oxidizing gas,
In the adsorption step, the reaction chamber is set to 0.133 Pa to 13.3 kPa, the monovalent aminosilane is supplied into the reaction chamber at 10 sccm to 10 slm , and SiH ₃ (NHC (CH ₃ ) _{3), or, SiH 3 (N (CH 3} ) 2) Ru with, method of forming a silicon oxide film, characterized in that.   The method for forming a silicon oxide film according to claim 1, wherein in the silicon oxide film forming step, the reaction chamber is set to 0.133 Pa to 13.3 kPa.   3. The method of forming a silicon oxide film according to claim 1, wherein, in the silicon oxide film forming step, an oxidizing gas is supplied to the reaction chamber in an amount of 1 sccm to 10 slm.   In the silicon oxide film forming step, an oxidizing gas is supplied to the plasma generating chamber set to 0.133 Pa to 13.3 kPa to form oxidizing gas radicals, and the oxidizing gas radicals are formed from the plasma generating chamber to the plasma generating chamber. The silicon oxide film forming method according to claim 1, wherein the silicon oxide film is supplied into a reaction chamber.   In the silicon oxide film formation step, ozone is activated by supplying ozone into a reaction chamber set to 200 ° C. to 600 ° C., and the activated ozone is supplied to the adsorbed silicon. The method for forming a silicon oxide film according to claim 1, wherein a silicon oxide film is formed on the object to be processed by oxidation. A reaction chamber for accommodating a workpiece,
An aminosilane supply means for supplying monovalent aminosilane into the reaction chamber;
An oxidizing gas supply means for supplying an activated oxidizing gas to the object to be processed;
Control means for controlling each part of the apparatus,
The control means includes
By controlling the aminosilane supply means, the reaction chamber is set to 0.133 Pa to 13.3 kPa, the monovalent aminosilane is supplied to the reaction chamber at 10 sccm to 10 slm, and silicon is adsorbed on the object to be processed.
Controlling the oxidizing gas supply means to supply an activated oxidizing gas to the adsorbed silicon, oxidize the silicon, and form a silicon oxide film on the object to be processed;
Repeat the process multiple times,
The reaction chamber is set to room temperature to 700 ° C.,
The oxidizing gas is oxygen, ozone or, Ri steam der,
The monovalent _{aminosilane, SiH 3 (NHC (CH 3} ) 3), _{or, SiH 3 (N (CH 3} ) 2) der Ru, forming apparatus of a silicon oxide film, characterized in that. Computer
An aminosilane supply means for supplying monovalent aminosilane into the reaction chamber containing the object to be treated;
An oxidizing gas supply means for supplying an activated oxidizing gas to the object to be processed;
By controlling the aminosilane supply means, the reaction chamber is set to 0.133 Pa to 13.3 kPa, the monovalent aminosilane is supplied to the reaction chamber at 10 sccm to 10 slm, and silicon is adsorbed on the object to be processed. Control that repeats the process a plurality of times by controlling the oxidizing gas supply means, supplying activated oxidizing gas to the adsorbed silicon, oxidizing the silicon, and forming a silicon oxide film on the object to be processed means,
Function as
The reaction chamber is set to room temperature to 700 ° C.,
The oxidizing gas is oxygen, ozone or, Ri steam der,
The monovalent _{aminosilane, SiH 3 (NHC (CH 3} ) 3), _{or, SiH 3 (N (CH 3} ) 2) Ru der, program characterized by.

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