JP5797790B2 - Semiconductor device manufacturing method, substrate processing method, and substrate processing apparatus - Google Patents

Description

  The present invention relates to a semiconductor device manufacturing method and a substrate processing apparatus including a step of forming a thin film on a substrate.

A flash memory has an electron storage region (floating gate) surrounded by an insulating film, and writes information by exchanging electrons through a thin tunnel oxide film, and at the same time uses the insulating properties of this thin oxide film. The principle of operation is to hold electrons for a long time and keep the memory. The information stored in the flash memory needs to be held for a long time of 10 years even if no operation is performed from the outside, and the demand for an insulating film surrounding a charge storage region called a floating gate is becoming strict. In an interlayer insulating film provided between the control gate for controlling the operation of the memory cell, an oxide film (SiO ₂ ) / nitride film (Si ₃ N ₄ ) / oxide film (SiO ₂ ) generally called ONO is laminated. The structure is used and is expected to have high leakage current characteristics.

Conventionally, the SiO ₂ insulating film formation in the ONO laminated structure has been performed at a high temperature around 800 ° C. by a CVD method using, for example, SiH ₂ Cl ₂ gas and N ₂ O gas, but for further miniaturization of devices. As a result, the capacity of the nitride film in the ONO multilayer film is reduced, and therefore, from the viewpoint of securing the capacity, the use of a high dielectric film instead of the nitride film layer has been studied. The SiO ₂ insulating film formed on the high dielectric film needs to be formed at a temperature lower than the high dielectric film formation temperature in order to suppress crystallization of the high dielectric film.

Japanese Patent Application No. 2009-178309

In the case of forming a SiO ₂ insulating film, the film growth rate (deposition rate) tends to become slow as the formation temperature is lowered. Therefore, an inorganic raw material or an organic raw material that has high reactivity and is easy to adsorb the raw material on the substrate is used. However, these raw materials have a problem in that the unit price of the formed semiconductor device is high because the amount of distribution is small and the raw material price is high compared with the conventional raw materials. In addition, when these raw materials are used, there is a problem that it is difficult to ensure the film thickness uniformity of the formed insulating film.

  Therefore, an object of the present invention is to solve the above-described problems and to provide a semiconductor device capable of forming an insulating film with good film thickness uniformity at low cost while maintaining a high film formation rate even at a low temperature. It is to provide a manufacturing method and a substrate processing apparatus.

According to one aspect of the invention,
Carrying a substrate into a processing container;
Forming a predetermined element-containing layer on the substrate by supplying and exhausting a first source gas containing a predetermined element and a second source gas containing the predetermined element in the processing container; and the processing Modifying the predetermined element-containing layer into an oxide layer, a nitride layer, or an oxynitride layer by supplying and exhausting a reactive gas different from the first source gas and the second source gas into the container; and , And alternately performing a process of forming an oxide film, a nitride film or an oxynitride film having a predetermined thickness on the substrate;
And a step of carrying out the processed substrate from the processing container,
The first source gas is more reactive than the second source gas,
In the step of forming the predetermined element-containing layer, a method for manufacturing a semiconductor device is provided in which the supply amount of the first source gas is less than the supply amount of the second source gas.

According to another aspect of the invention,
Carrying a substrate into a processing container;
Forming a silicon-containing layer on the substrate by supplying and exhausting a first source gas containing silicon and a second source gas containing silicon in the processing vessel; and Modifying the silicon-containing layer into a silicon oxide layer, a silicon nitride layer, or a silicon oxynitride layer by supplying and exhausting a reactive gas different from the first source gas and the second source gas; A process of forming a silicon oxide film, a silicon nitride film, or a silicon oxynitride film having a predetermined film thickness on the substrate by repeating alternately;
And a step of carrying out the processed substrate from the processing container,
The first source gas is more reactive than the second source gas,
In the step of forming the silicon-containing layer, a method of manufacturing a semiconductor device is provided in which the supply amount of the first source gas is less than the supply amount of the second source gas.

According to yet another aspect of the invention,
A processing container for containing a substrate;
A first source gas supply system for supplying a first source gas containing a predetermined element in the processing container;
A second source gas supply system for supplying a second source gas containing the predetermined element into the processing container;
A reaction gas supply system for supplying a reaction gas different from the first source gas and the second source gas into the processing container;
An exhaust system for exhausting the inside of the processing vessel;
A process of forming a predetermined element-containing layer on the substrate by supplying and exhausting the first source gas and the second source gas into the processing container containing the substrate; and in the processing container A process of modifying the predetermined element-containing layer into an oxide layer, a nitride layer, or an oxynitride layer by supplying and exhausting the reactive gas is alternately repeated, whereby an oxide film having a predetermined thickness is formed on the substrate. A control unit for controlling the first source gas supply system, the second source gas supply system, the reaction gas supply system, and the exhaust system so as to perform a process of forming a nitride film or an oxynitride film; Have
The first source gas is more reactive than the second source gas,
The controller further includes the first source gas so that the supply amount of the first source gas is less than the supply amount of the second source gas in the process of forming the predetermined element-containing layer. A substrate processing apparatus configured to control a supply system and the second source gas supply system is provided.

  According to the present invention, there is provided a method for manufacturing a semiconductor device and a substrate processing apparatus capable of forming an insulating film with good film thickness uniformity at low cost while maintaining a high film formation rate even at low temperatures. Can be provided.

It is a schematic block diagram of the vertical processing furnace of the substrate processing apparatus used suitably by this embodiment, and is a figure which shows a processing furnace part with a vertical cross section. It is a schematic block diagram of the vertical processing furnace of the substrate processing apparatus used suitably by this embodiment, and is a figure which shows a processing furnace part by the AA 'line sectional drawing of FIG. It is a figure which shows the film-forming flowchart in this embodiment. Is a diagram showing the timing of gas supply in the film forming sequence of the embodiment, after the supply of the HCD gas and DCS gas simultaneously stopping the supply of the HCD gas and DCS gas simultaneously, then O ₂ gas and H ₂ An example of supplying gas is shown. It is a figure which shows the timing of the gas supply in the film-forming sequence of this embodiment, and after supplying HCD gas and DCS gas simultaneously, after stopping supply of HCD gas and stopping supply of DCS gas, it is O It shows an example of supplying a ₂ gas and H ₂ gas. It is a figure which shows the timing of the gas supply in the film-forming sequence of this embodiment, supplies HCD gas ahead of DCS gas supply, stops supply of HCD gas first, and stops supply of DCS gas Then, an example in which O ₂ gas and H ₂ gas are supplied is shown. When DCS gas is used alone, when a gas obtained by adding a small amount of HCD gas to DCS gas, or when a trace amount of HCD gas is used alone, the film formation rate and film thickness uniformity of each SiO ₂ film are tested. It is a figure showing a result. Is a graph showing the relationship between the supply amount and the deposition rate of the SiO ₂ film of the HCD gas. It is a figure which shows the timing of the gas supply in the film-forming sequence at the time of applying this invention to SiN film formation, and after supplying HCD gas and DCS gas simultaneously, supply of HCD gas is stopped | fastened first and DCS gas is supplied. In the example, NH ₃ gas is supplied after the supply is stopped. It is a figure which shows the timing of the gas supply in the film-forming sequence at the time of applying this invention to SiON film-forming, and after supplying HCD gas and DCS gas simultaneously, supply of HCD gas is stopped | fastened first and DCS gas is supplied. In the example, NH ₃ gas is supplied after supply is stopped, and then O ₂ gas is supplied. It is a figure which shows the relationship between the HCD / DCS flow rate ratio and the SiO film-forming speed | rate which concern on the Example of this invention. It is a figure which shows the relationship between the HCD / DCS flow rate ratio and SiO film thickness uniformity which concern on the Example of this invention.

In a silicon raw material: dichlorosilane (SiH ₂ Cl ₂ , abbreviated as DCS) widely used in the case of forming a SiO ₂ film by a conventional CVD (Chemical Vapor Deposition) method, as the film forming temperature is lowered, the reactivity is increased. And the incubation of adsorption / deposition on the substrate (SiO ₂ , SiON, SiN, etc.) increases. Therefore, it becomes extremely difficult to form a silicon layer of less than one atomic layer to several atomic layers on the substrate. In addition, the uniformity of the thickness distribution of the SiO ₂ film obtained at this time is markedly bad by dragging silicon layer formation spots.

FIG. 7 shows film formation speed and film thickness uniformity when an SiO ₂ film is formed on a substrate at a low temperature (600 ° C.) by alternately supplying a silicon source gas and a reaction gas (oxygen gas and hydrogen gas). The experimental results are shown. FIG. 7A shows the film forming speed and film thickness uniformity when DCS gas is used alone as the silicon source gas. FIG. 7B shows the film forming speed and film thickness uniformity when a gas obtained by adding a small amount of HCD gas to DCS gas is used as the silicon source gas. FIG. 7C shows the film forming speed and film thickness uniformity when a trace amount of HCD gas is used alone as the silicon source gas. When the flow rate of the DCS gas used in the experiment of FIG. 7 is 1, the flow rate of the trace amount HCD gas is represented by 0.03. That is, the ratio of the flow rate of the HCD gas to the flow rate of the DCS gas used in the experiment of FIG. 7, that is, the HCD gas flow rate / DCS gas flow rate (HCD / DCS flow rate ratio) is 0.03% (3%). In FIG. 7, the film formation rate is shown as a film formation rate ratio when the film formation rate of (a) is 1 (reference), and the film thickness uniformity is the film thickness uniformity of (a). Is shown as a film thickness uniformity ratio when 1 is set as 1 (reference). The film thickness uniformity indicates the degree of variation in the film thickness distribution in the substrate surface, and the smaller the value, the better the film thickness uniformity in the substrate surface.

As a result of diligent research, the inventors have higher reactivity than DCS gas, that is, one of the inorganic raw materials that has a lower thermal decomposition temperature than DCS gas and is easier to adsorb on the substrate than DCS gas under similar conditions. By adding a small amount of hexachlorodisilane (Si ₂ Cl ₆ , abbreviated as HCD) gas to the DCS gas, it is possible to improve the deposition rate of the SiO ₂ film at a low temperature, for example, 600 ° C. It was found that the film thickness uniformity of the _two films can be improved. As shown in FIG. 7B, it can be seen that by adding a small amount of HCD gas to the DCS gas, a film formation rate 2.2 times that obtained when the DCS gas is used alone can be obtained. It can also be seen that by adding a small amount of HCD gas to DCS gas, extremely good film thickness uniformity can be obtained as compared with the case where DCS gas is used alone. Note that the film formation rate of the SiO ₂ film when a very small amount of HCD gas is used alone is extremely low as shown in FIG. 7C, and the thickness distribution uniformity of the SiO ₂ film obtained at this time is also remarkably high. I know it ’s bad.

8, the formation of the supply amount and the SiO ₂ film of the HCD gas when forming the SiO ₂ film under a low temperature (600 ° C.) is supplied alternately with HCD gas and reaction gas (oxygen gas and hydrogen gas) It is a graph showing the relationship with speed. FIG. 8 shows the relationship between the HCD gas supply rate and the SiO ₂ film deposition rate when the deposition rate is normalized with reference to a certain HCD supply rate. FIG. 8 shows that the film formation rate of the SiO ₂ film is decreased due to the decrease in the amount of silicon adsorbed on the substrate as the HCD gas supply amount is decreased. That is, when the HCD gas is used alone, the film formation rate cannot be improved even if the supply amount of the HCD gas is reduced and the supply amount of the HCD gas is made very small. In order to secure the film forming rate when the HCD gas is used alone, a certain amount of HCD gas needs to be supplied. Even when DCS gas is used alone, the film formation rate cannot be improved at low temperatures. However, by adding a small amount of HCD gas to DCS gas, it is possible to improve the deposition rate even at a low temperature such as 600 ° C.

  The reason why the film forming speed can be improved by adding a small amount of HCD gas to the DCS gas is that, by supplying a small amount of HCD onto the substrate, silicon material is adsorbed and silicon is deposited to some extent. Compared to the case where a small amount of HCD is not added, the site where DCS adsorption / silicon deposition is required is narrowed. As a result, the exposure amount of DCS to the site is relatively increased, and the DCS adsorption probability / This is probably because the probability of silicon deposition is significantly improved.

In addition, by DCS gas are simultaneously supplied HCD gas is thermally decomposed, also by Cl ₂ which HCD gas is generated during the thermal decomposition reacts with H groups DCS gas, the SiCl ₄ gas and Si atoms The generation is accelerated and the adsorption of silicon raw material and the deposition of silicon are greatly accelerated. This is also considered as a reason why the film formation rate can be improved. At this time, it is considered that the following reaction proceeds.

2SiH ₂ Cl ₂ + Si ₂ Cl ₆ → 2Si + 2SiCl ₄ + 2HCl + H ₂
SiH ₂ Cl ₂ + Si ₂ Cl ₆ → 2Si + SiCl ₄ + 2HCl
SiH ₂ Cl ₂ + Si ₂ Cl ₆ → Si + 2SiCl ₄ + H ₂

As a result, it is possible to improve the film formation speed and to uniformly adsorb silicon material and deposit silicon on the substrate. Therefore, the film thickness uniformity (film thickness) of the SiO ₂ film formed in the present invention Distribution) is also considered to be good. In addition, compared to the case where HCD gas is used alone, the raw material cost can be significantly reduced without lowering the film formation controllability.

  When the HCD gas as the first silicon source gas is Si source A and the DCS gas as the second silicon source gas is Si source B, the supply timing of each Si source is as shown in FIG. 1 (Si material A and B simultaneous supply), FIG. 5 Si material supply timing 2 (Si material A and B simultaneous supply, Si material B post-cut), FIG. 6 Si material supply timing 3 (Si material A advance, Si Any post-feed timing may be used. In addition, the experimental result of FIG.7 (b) is a result performed at the Si raw material supply timing 2 of FIG. Details of these Si raw material supply timings will be described later.

  The present invention has been made based on such knowledge obtained by the inventors. Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

  FIG. 1 is a schematic configuration diagram of a vertical processing furnace of a substrate processing apparatus suitably used in an embodiment of the present invention, and shows a processing furnace 202 portion in a vertical sectional view. FIG. 2 is a cross-sectional view taken along the line A-A ′ of the processing furnace shown in FIG. 1. The present invention is not limited to the substrate processing apparatus according to the present embodiment, and can be suitably applied to a substrate processing apparatus having a single wafer type, hot wall type, or cold wall type processing furnace.

  As shown in FIG. 1, the processing furnace 202 includes a heater 207 as a heating means (heating mechanism). The heater 207 has a cylindrical shape and is vertically installed by being supported by a heater base (not shown) as a holding plate.

Inside the heater 207, a process tube 203 as a reaction tube is disposed concentrically with the heater 207. The process tube 203 is made of a heat resistant material such as quartz (SiO ₂ ) or silicon carbide (SiC), and is formed in a cylindrical shape with the upper end closed and the lower end opened. A process chamber 201 is formed in a cylindrical hollow portion of the process tube 203 so that wafers 200 as substrates can be accommodated by a boat 217, which will be described later, in a horizontal posture and aligned in multiple stages in the vertical direction.

  A manifold 209 is disposed below the process tube 203 concentrically with the process tube 203. The manifold 209 is made of, for example, stainless steel and is formed in a cylindrical shape with an upper end and a lower end opened. The manifold 209 is engaged with the process tube 203 and is provided to support the process tube 203. An O-ring 220a as a seal member is provided between the manifold 209 and the process tube 203. Since the manifold 209 is supported by the heater base, the process tube 203 is installed vertically. A reaction vessel (processing vessel) is formed by the process tube 203 and the manifold 209.

  The manifold 209 includes a first nozzle 233a as a first gas introduction part, a second nozzle 233b as a second gas introduction part, and a third nozzle 233c as a third gas introduction part. A first gas supply pipe 232a, a second gas supply pipe 232b, and a third gas supply pipe 232c are connected to the first nozzle 233a, the second nozzle 233b, and the third nozzle 233c, respectively. ing. A fourth gas supply pipe 232d is connected to the third gas supply pipe 232c. As described above, four gas supply pipes are provided in the processing chamber 201 as gas supply paths for supplying a plurality of types, here, four types of processing gases.

  The first gas supply pipe 232a is provided with a mass flow controller 241a as a flow rate controller (flow rate control means) and a valve 243a as an on-off valve in order from the upstream direction. A first inert gas supply pipe 234a that supplies an inert gas is connected to the downstream side of the valve 243a of the first gas supply pipe 232a. The first inert gas supply pipe 234a is provided with a mass flow controller 241c that is a flow rate controller (flow rate control means) and a valve 243c that is an on-off valve in order from the upstream direction. The first nozzle 233a is connected to the tip of the first gas supply pipe 232a. The first nozzle 233a is placed in an arcuate space between the inner wall of the process tube 203 constituting the processing chamber 201 and the wafer 200 along the upper direction from the lower part of the inner wall of the process tube 203, in the loading direction of the wafer 200. It is provided to rise upward. A gas supply hole 248a that is a supply hole for supplying a gas is provided on a side surface of the first nozzle 233a. The gas supply holes 248a have the same opening area from the lower part to the upper part, and are provided at the same opening pitch. A first gas supply system is mainly configured by the first gas supply pipe 232a, the mass flow controller 241a, the valve 243a, and the first nozzle 233a. In addition, a first inert gas supply system is mainly configured by the first inert gas supply pipe 234a, the mass flow controller 241c, and the valve 243c.

  The second gas supply pipe 232b is provided with a mass flow controller 241b as a flow rate controller (flow rate control means) and a valve 243b as an on-off valve in order from the upstream direction. A second inert gas supply pipe 234b that supplies an inert gas is connected to the downstream side of the valve 243b of the second gas supply pipe 232b. The second inert gas supply pipe 234b is provided with a mass flow controller 241d as a flow rate controller (flow rate control means) and a valve 243d as an on-off valve in order from the upstream direction. The second nozzle 233b is connected to the tip of the second gas supply pipe 232b. The second nozzle 233b is placed in an arc-shaped space between the inner wall of the process tube 203 constituting the processing chamber 201 and the wafer 200, along the upper portion from the lower portion of the inner wall of the process tube 203, in the loading direction of the wafer 200. It is provided to rise upward. A gas supply hole 248b, which is a supply hole for supplying gas, is provided on the side surface of the second nozzle 233b. The gas supply holes 248b have the same opening area from the lower part to the upper part, and are provided at the same opening pitch. A second gas supply system is mainly configured by the second gas supply pipe 232b, the mass flow controller 241b, the valve 243b, and the second nozzle 233b. In addition, a second inert gas supply system is mainly configured by the second inert gas supply pipe 234b, the mass flow controller 241d, and the valve 243d.

  The third gas supply pipe 232c is provided with a mass flow controller 241e as a flow rate controller (flow rate control means) and a valve 243e as an on-off valve in order from the upstream direction. Further, a third inert gas supply pipe 234c for supplying an inert gas is connected to the downstream side of the valve 243e of the third gas supply pipe 232c. The third inert gas supply pipe 234c is provided with a mass flow controller 241f as a flow rate controller (flow rate control means) and a valve 243f as an on-off valve in order from the upstream direction. A fourth gas supply pipe 232d is connected to the downstream side of the valve 243e of the third gas supply pipe 232c. The fourth gas supply pipe 232d is provided with a mass flow controller 241g that is a flow rate controller (flow rate control means) and a valve 243g that is an on-off valve in order from the upstream direction. The third nozzle 233c described above is connected to the tip of the third gas supply pipe 232c. The third nozzle 233c is placed in the arc-shaped space between the inner wall of the process tube 203 constituting the processing chamber 201 and the wafer 200, along the upper portion from the lower portion of the inner wall of the process tube 203, in the loading direction of the wafer 200. It is provided to rise upward. A gas supply hole 248c, which is a supply hole for supplying gas, is provided on the side surface of the third nozzle 233c. The gas supply holes 248c have the same opening area from the lower part to the upper part, and are provided at the same opening pitch. A third gas supply system is mainly configured by the third gas supply pipe 232c, the mass flow controller 241e, the valve 243e, and the third nozzle 233c. Further, a fourth gas supply system is mainly configured by the fourth gas supply pipe 232d, the mass flow controller 241g, the valve 243g, the third gas supply pipe 232c, and the third nozzle 233c. Further, the third inert gas supply system is mainly configured by the third inert gas supply pipe 234c, the mass flow controller 241f, and the valve 243f.

From the first gas supply pipe 232a, for example, oxygen (O ₂ ) gas is supplied as oxygen-containing gas (oxygen-containing gas) into the processing chamber 201 via the mass flow controller 241a, the valve 243a, and the first nozzle 233a. The That is, the first gas supply system is configured as an oxygen-containing gas supply system. At the same time, the inert gas may be supplied from the first inert gas supply pipe 234a into the first gas supply pipe 232a via the mass flow controller 241c and the valve 243c.

Further, from the second gas supply pipe 232b, for example, hydrogen (H ₂ ) gas as hydrogen-containing gas (hydrogen-containing gas) enters the processing chamber 201 via the mass flow controller 241b, the valve 243b, and the second nozzle 233b. Supplied. That is, the second gas supply system is configured as a hydrogen-containing gas supply system. At the same time, the inert gas may be supplied from the second inert gas supply pipe 234b into the second gas supply pipe 232b via the mass flow controller 241d and the valve 243d.
From the second gas supply pipe 232b, for example, ammonia (NH ₃ ) gas as nitrogen-containing gas (nitrogen-containing gas) enters the processing chamber 201 through the mass flow controller 241b, the valve 243b, and the second nozzle 233b. It may be supplied. That is, the second gas supply system may be configured as a nitrogen-containing gas supply system. At the same time, the inert gas may be supplied from the second inert gas supply pipe 234b into the second gas supply pipe 232b via the mass flow controller 241d and the valve 243d.

Further, from the third gas supply pipe 232c, for example, hexachlorodisilane (Si ₂ Cl ₆ , abbreviated as HCD) gas is used as the first source gas, that is, the first source gas containing silicon (first silicon-containing gas). Is supplied into the processing chamber 201 via the mass flow controller 241e, the valve 243e, and the third nozzle 233c. That is, the third gas supply system is configured as a first source gas supply system (first silicon-containing gas supply system). At the same time, the inert gas may be supplied from the third inert gas supply pipe 234c into the third gas supply pipe 232c via the mass flow controller 241f and the valve 243f.

Further, from the fourth gas supply pipe 232d, for example, dichlorosilane (SiH ₂ Cl ₂ , abbreviated as DCS) gas is used as the second source gas, that is, the second source gas containing silicon (second silicon-containing gas). Is supplied into the processing chamber 201 through the mass flow controller 241g, the valve 243g, the third gas supply pipe 232c, and the third nozzle 233c. That is, the fourth gas supply system is configured as a second source gas supply system (second silicon-containing gas supply system). At the same time, the inert gas may be supplied from the third inert gas supply pipe 234c into the third gas supply pipe 232c via the mass flow controller 241f and the valve 243f.

  The first gas supply system and the second gas supply system constitute a reactive gas supply system, and the third gas supply system and the fourth gas supply system constitute a source gas supply system.

In the present embodiment, _{O 2} gas, _{H 2} gas (NH ₃ gas), the HCD gas and DCS gas, but is then supplied to the processing chamber 201 from their respective separate nozzles, eg, _{H 2} gas And HCD gas may be supplied into the processing chamber 201 from the same nozzle. Alternatively, O ₂ gas and H ₂ gas may be supplied into the processing chamber 201 from the same nozzle. As described above, if the nozzles are shared by a plurality of types of gases, the number of nozzles can be reduced, the apparatus cost can be reduced, and maintenance can be facilitated. Further, by supplying the O ₂ gas and the H ₂ gas from the same nozzle into the processing chamber 201, it becomes possible to enhance the oxidizing power improving effect and the oxidizing power uniformizing effect. In the deposition temperature range to be described later, but do not react with HCD gas and H ₂ gas, since it is considered to react with HCD gas and O ₂ gas, from different nozzles and HCD gas and O ₂ gas It is better to supply it into the processing chamber 201. In the present embodiment, the HCD gas and the DCS gas are mixed in advance in the same supply pipe (third gas supply pipe 232c) and supplied into the processing chamber 201 from the same nozzle (third nozzle 233c). However, they may be supplied into the barber room 201 from separate supply pipes and nozzles.

  The manifold 209 is provided with an exhaust pipe 231 that exhausts the atmosphere in the processing chamber 201. A vacuum pump 246 as a vacuum exhaust device is connected to the exhaust pipe 231 via a pressure sensor 245 as a pressure detector and an APC (Auto Pressure Controller) valve 242 as a pressure regulator (pressure adjustment unit). . The APC valve 242 is an open / close valve configured to open / close the valve to stop evacuation / evacuation in the processing chamber 201 and to adjust the pressure by adjusting the valve opening. By adjusting the opening degree of the APC valve 242 based on the pressure detected by the pressure sensor 245 while operating the vacuum pump 246, the pressure in the processing chamber 201 becomes a predetermined pressure (degree of vacuum). It is configured to be evacuated. An exhaust system is mainly configured by the exhaust pipe 231, the pressure sensor 245, the APC valve 242, and the vacuum pump 246.

  Below the manifold 209, a seal cap 219 is provided as a furnace port lid that can airtightly close the lower end opening of the manifold 209. The seal cap 219 is configured to contact the lower end of the manifold 209 from the lower side in the vertical direction. The seal cap 219 is made of a metal such as stainless steel and has a disk shape. On the upper surface of the seal cap 219, an O-ring 220b is provided as a seal member that contacts the lower end of the manifold 209. On the opposite side of the seal cap 219 from the processing chamber 201, a rotation mechanism 267 for rotating a boat 217 as a substrate holder described later is installed. A rotation shaft 255 of the rotation mechanism 267 passes through the seal cap 219 and is connected to the boat 217. The rotation mechanism 267 is configured to rotate the wafer 200 by rotating the boat 217. The seal cap 219 is configured to be lifted and lowered in the vertical direction by a boat elevator 115 as a lifting mechanism that is vertically installed outside the process tube 203. The boat elevator 115 is configured such that the boat 217 can be carried into and out of the processing chamber 201 by moving the seal cap 219 up and down.

  A boat 217 as a substrate holder is made of a heat-resistant material such as quartz or silicon carbide, and holds a plurality of wafers 200 in a horizontal posture and in a state where the centers are aligned with each other and held in multiple stages. It is configured. A heat insulating member 218 made of a heat resistant material such as quartz or silicon carbide is provided at the lower part of the boat 217 so that heat from the heater 207 is not easily transmitted to the seal cap 219 side. . The heat insulating member 218 may be constituted by a plurality of heat insulating plates made of a heat resistant material such as quartz or silicon carbide, and a heat insulating plate holder that supports the heat insulating plates in a horizontal posture in multiple stages. A temperature sensor 263 as a temperature detector is installed in the process tube 203, and the temperature in the processing chamber 201 is adjusted by adjusting the degree of energization to the heater 207 based on the temperature information detected by the temperature sensor 263. Is configured to have a desired temperature distribution. The temperature sensor 263 is provided along the inner wall of the process tube 203, similarly to the first nozzle 233a, the second nozzle 233b, and the third nozzle 233c.

  The controller 280 as a control unit (control means) includes mass flow controllers 241a, 241b, 241c, 241d, 241e, 241f, 241g, valves 243a, 243b, 243c, 243d, 243e, 243f, 243g, pressure sensors 245, APC valves 242. , Heater 207, temperature sensor 263, vacuum pump 246, rotation mechanism 267, boat elevator 115, and the like. The controller 280 controls the gas flow rate by the mass flow controllers 241a, 241b, 241c, 241d, 241e, 241f, 241g, the opening / closing operation of the valves 243a, 243b, 243c, 243d, 243e, 243f, 243g, the opening / closing of the APC valve 242 and the pressure sensor. The pressure adjustment operation based on H.245, the temperature adjustment of the heater 207 based on the temperature sensor 263, the start / stop of the vacuum pump 246, the rotation speed adjustment of the rotation mechanism 267, and the lifting / lowering operation of the boat 217 by the boat elevator 115 are performed.

  Next, an example of a method for forming an oxide film as an insulating film on a substrate as a process of manufacturing a semiconductor device (device) using the above-described processing furnace of the substrate processing apparatus will be described. In the following description, the operation of each part constituting the substrate processing apparatus is controlled by the controller 280.

FIG. 3 shows a film formation flow chart in the present embodiment, and FIGS. 4, 5, and 6 show gas supply timing charts in the film formation sequence of the present embodiment. In the film forming sequence according to the present embodiment, a first source gas containing silicon (HCD gas) and silicon are included as at least two types of source gases containing silicon as a predetermined element in a processing container containing a substrate. A step of forming a silicon-containing layer as a predetermined element-containing layer on the substrate by supplying a second source gas (DCS gas); and a first source gas and a second source gas in the processing container; By alternately supplying an oxygen-containing gas (O ₂ gas) and a hydrogen-containing gas (H ₂ gas) as different reaction gases, the step of modifying the silicon-containing layer into a silicon oxide layer is alternately repeated. Then, a silicon oxide film having a predetermined thickness is formed on the substrate. Note that the first source gas is more reactive than the second source gas, and in the step of forming the silicon-containing layer on the substrate, the supply amount of the first source gas is changed to the supply amount of the second source gas. Less than.

  The step of forming the silicon-containing layer on the substrate is performed under conditions that cause a CVD reaction. At this time, a silicon layer as a silicon-containing layer of less than one atomic layer to several atomic layers is formed on the substrate. The silicon-containing layer may be an adsorption layer for each source gas, that is, an adsorption layer for the first source gas or an adsorption layer for the second source gas. Here, the silicon layer is a generic name including a continuous layer made of silicon, a discontinuous layer, and a silicon thin film formed by overlapping these layers. A continuous layer made of silicon may be referred to as a silicon thin film. The source gas adsorption layer includes a discontinuous chemical adsorption layer in addition to a continuous chemical adsorption layer of gas molecules of the source gas. In addition, the layer less than 1 atomic layer means the atomic layer formed discontinuously. Under conditions where the source gas self-decomposes, silicon is deposited on the substrate to form a silicon layer. Under the condition that the source gas does not self-decompose, the source gas is adsorbed on the substrate to form an adsorption layer of the source gas. Note that it is preferable to form a silicon layer on the substrate, rather than forming a source gas adsorption layer on the substrate, because the film formation rate can be increased.

  In the step of modifying the silicon-containing layer into the silicon oxide layer, the reaction gas is activated by heat and supplied to oxidize the silicon-containing layer and modify it into the silicon oxide layer. At this time, an oxygen-containing gas as a reaction gas and a hydrogen-containing gas are reacted in a processing container under a pressure atmosphere less than atmospheric pressure to generate an oxygen-containing oxidizing species, and the silicon-containing layer is oxidized by the oxidizing species. Then, the silicon oxide layer is modified. According to this oxidation treatment, the oxidizing power can be greatly improved as compared with the case where the oxygen-containing gas is supplied alone. That is, by adding a hydrogen-containing gas to an oxygen-containing gas in a reduced-pressure atmosphere, a significant effect of improving the oxidizing power can be obtained compared to the case of supplying an oxygen-containing gas alone. The step of modifying the silicon-containing layer into an oxide layer is performed in a non-plasma reduced pressure atmosphere. In addition, as a reactive gas, oxygen-containing gas can also be used independently.

(Application to SiO film formation)
This will be specifically described below. In the present embodiment, HCD gas is used as the first source gas containing silicon, DCS gas is used as the second source gas containing silicon, oxygen-containing gas as the reactive gas, O ₂ gas as the hydrogen-containing gas, H ₂ An example in which a silicon oxide film (SiO ₂ film) is formed as an insulating film on a substrate by using _two gases, respectively, according to the film formation flow of FIG. 3 and the film formation sequences of FIGS. 4, 5, and 6 will be described.

  When a plurality of wafers 200 are loaded into the boat 217 (wafer charge), as shown in FIG. 1, the boat 217 holding the plurality of wafers 200 is lifted by the boat elevator 115 and processed in the processing chamber 201. It is carried in (boat loading). In this state, the seal cap 219 seals the lower end of the manifold 209 via the O-ring 220b.

  The processing chamber 201 is evacuated by a vacuum pump 246 so that a desired pressure (degree of vacuum) is obtained. At this time, the pressure in the processing chamber 201 is measured by the pressure sensor 245, and the APC valve 242 is feedback-controlled based on the measured pressure (pressure adjustment). Further, the processing chamber 201 is heated by the heater 207 so as to have a desired temperature. At this time, the power supply to the heater 207 is feedback-controlled based on the temperature information detected by the temperature sensor 263 so that the inside of the processing chamber 201 has a desired temperature distribution (temperature adjustment). Subsequently, the wafer 200 is rotated by rotating the boat 217 by the rotation mechanism 267. Thereafter, the following four steps are sequentially executed.

[Step 1]
The valve 243e of the third gas supply pipe 232c and the valve 243f of the third inert gas supply pipe 234c are opened, the HCD gas is supplied to the third gas supply pipe 232c, and the inert gas (for example, N _{2 is} supplied to the third inert gas supply pipe 234c). Gas). Further, the valve 243g of the fourth gas supply pipe 232d is opened, and the DCS gas is caused to flow through the fourth gas supply pipe 232d. The inert gas flows from the third inert gas supply pipe 234c, and the flow rate is adjusted by the mass flow controller 241f. The HCD gas flows from the third gas supply pipe 232c and the flow rate is adjusted by the mass flow controller 241e. The DCS gas flows from the fourth gas supply pipe 232d and the flow rate is adjusted by the mass flow controller 241g. The HCD gas whose flow rate is adjusted, the DCS gas whose flow rate is adjusted, and the inert gas whose flow rate is adjusted are mixed in the third gas supply pipe 232c and heated from the gas supply hole 248c of the third nozzle 233c. Then, it is supplied into the processing chamber 201 in a reduced pressure state and exhausted from the exhaust pipe 231 (HCD and DCS supply).

  At this time, as shown in FIGS. 4, 5, and 6, the supply amount of the HCD gas in step 1 is made smaller than the supply amount of the DCS gas. That is, the supply amount of HCD gas with respect to the supply amount of DCS gas in step 1 is set to a very small amount. 4, 5, and 6, the horizontal axis represents time, and the vertical axis represents the supply flow rate of each gas. The rectangular area indicating the supply state of each gas in each step represents the area of each rectangle in each step. The supply amount of each gas is shown.

  The ratio of the supply amount of the HCD gas to the supply amount of the DCS gas in step 1, that is, the HCD supply amount / DCS supply amount (HCD / DCS) is 0.03 (3%) or more and 0.5 (50%) or less. Of 0.06 (6%) to 0.5 (50%) is more preferable. If the HCD / DCS is less than 3%, the probability of adsorption of DCS on the wafer surface and the probability of silicon deposition will decrease, making it difficult to increase the film formation rate and ensuring film thickness uniformity. It becomes difficult. If HCD / DCS is less than 6%, the adsorption / deposition of HCD and DCS on the wafer surface is not easily saturated. When HCD / DCS is larger than 50%, the potential for increasing by-products and particles increases. The raw material cost reduction effect is also reduced. That is, by setting HCD / DCS to 3% or more and 50% or less, the probability of adsorption / deposition of DCS on the wafer surface can be increased, the film formation rate can be increased, and the film thickness uniformity can be improved. It will also be possible. Furthermore, it is possible to suppress the generation of by-products and the generation of particles, and the raw material cost can be greatly reduced. Also, by setting HCD / DCS to 6% or more and 50% or less, it becomes easy to saturate the adsorption / deposition of HCD or DCS on the wafer surface, so that the film formation rate can be further increased. Moreover, the film thickness uniformity can be further improved. Furthermore, it is possible to suppress the generation of by-products and the generation of particles, and the raw material cost can be greatly reduced.

  In this case, as shown in FIG. 4, the supply flow rate of the HCD gas may be made smaller than the supply flow rate of the DCS gas, and the HCD gas and the DCS gas may be supplied simultaneously. That is, the supply flow rate of the HCD gas is made smaller than the supply flow rate of the DCS gas, the supply start and stop of supply of the HCD gas and the DCS gas are simultaneously performed, and the supply time of the HCD gas and the supply time of the DCS gas are made equal. It may be. In the case of the supply method of FIG. 4, the opening / closing timing of the valve 243e and the valve 243g can be matched, and the valve opening / closing control becomes easy.

  Further, as shown in FIG. 5, the supply flow rate of the HCD gas and the supply flow rate of the DCS gas are made equal, and the supply of the HCD gas is stopped first after supplying the HCD gas and the DCS gas at the same time. Also good. That is, the supply flow rate of the HCD gas and the supply flow rate of the DCS gas are made equal, the supply of the HCD gas and the DCS gas is started simultaneously, the supply of the HCD gas is stopped, and then the supply of the DCS gas alone is continued for a predetermined time. Then, the operation may be stopped and the supply time of the HCD gas may be made shorter than the supply time of the DCS gas. In the case of the supply method of FIG. 5, compared with the supply method of FIG. 4, the supply amount of the HCD gas at the initial stage of supplying the HCD gas and the DCS gas can be increased, and the DCS gas is adsorbed on the wafer surface at the initial supply stage. It is possible to quickly create a state that is easy to perform, and then to increase the adsorption efficiency of the DCS gas to the wafer surface when supplying the DCS gas alone.

  Further, as shown in FIG. 6, the supply flow rate of the HCD gas and the supply flow rate of the DCS gas may be made equal to supply the HCD gas prior to the supply of the DCS gas. That is, the supply flow rate of the HCD gas is made equal to the supply flow rate of the DCS gas, the supply of the HCD gas is started, the supply of the HCD gas is stopped, and the supply of the DCS gas is started at the same time. The supply time of the HCD gas may be shorter than the supply time of the DCS gas. In this case, after the supply of the HCD gas is started, the supply of the DCS gas is started without stopping the supply of the HCD gas, and then the supply of the HCD gas is stopped while the supply of the DCS gas is continued. Also good. Even in this case, the supply time of the HCD gas is made shorter than the supply time of the DCS gas. In the supply method of FIG. 6, by supplying the HCD gas before the DCS gas, it is possible to create a state in which the DCS gas is easily adsorbed on the wafer surface before the DCS gas is supplied, and then the DCS gas. The efficiency of adsorption of DCS gas onto the wafer surface can be increased when supplying the gas alone.

  Moreover, you may combine these supply methods suitably. For example, the supply flow rate of the HCD gas may be made smaller than the supply flow rate of the DCS gas, and the supply time of the HCD gas may be made shorter than the supply time of the DCS gas.

  If the supply amount of the HCD gas is made smaller than the supply amount of the DCS gas, for example, the supply flow rate of the HCD gas is made smaller than the supply flow rate of the DCS gas and the supply time of the HCD gas is set to supply the DCS gas. The HCD gas supply flow rate may be set longer than the DCS gas supply flow rate, and the HCD gas supply time may be set shorter than the DCS gas supply time.

  Thus, the supply flow rate of the HCD gas is made smaller than the supply flow rate of the DCS gas, the supply time of the HCD gas is made shorter than the supply time of the DCS gas, or the supply flow rate of the HCD gas is supplied to the DCS gas. By making the flow rate lower than the flow rate and making the supply time of the HCD gas shorter than the supply time of the DCS gas, the supply amount of the HCD gas is made smaller than the supply amount of the DCS gas.

  At this time, the APC valve 242 is appropriately adjusted to maintain the pressure in the processing chamber 201 at a pressure lower than atmospheric pressure, for example, in a range of 10 to 1000 Pa. The supply flow rate of the HCD gas controlled by the mass flow controller 241e is set to a flow rate in the range of 1 to 500 sccm, for example. The time for exposing the wafer 200 to the HCD gas is, for example, a time within a range of 1 to 120 seconds. The supply flow rate of the DCS gas controlled by the mass flow controller 241g is, for example, a flow rate in the range of 1 to 5000 sccm. The time for exposing the wafer 200 to the DCS gas is, for example, a time within a range of 1 to 120 seconds. The temperature of the heater 207 is set so that the CVD reaction occurs in the processing chamber 201. That is, the temperature of the heater 207 is set so that the temperature of the wafer 200 is, for example, in the range of 350 to 850 ° C., preferably 400 to 700 ° C. When the temperature of the wafer 200 is less than 350 ° C., it becomes difficult for HCD and DCS to be adsorbed on the wafer 200, and HCD and DCS are difficult to decompose. Further, when the temperature of the wafer 200 is less than 400 ° C., the film formation rate falls below the practical level. Further, when the temperature of the wafer 200 exceeds 700 ° C., particularly 850 ° C., the CVD reaction becomes strong and the uniformity tends to deteriorate. Therefore, the temperature of the wafer 200 is 350 to 850 ° C., preferably 400 to 700 ° C.

  By supplying HCD gas and DCS gas into the processing chamber 201 under the above-described conditions, a silicon layer (Si layer) as a silicon-containing layer of less than one atomic layer to several atomic layers on the wafer 200 (surface underlayer film). ) Is formed. The silicon-containing layer may be a chemical adsorption layer of HCD gas or a chemical adsorption layer of DCS gas. Note that, under conditions where the HCD gas and the DCS gas are self-decomposed, silicon is deposited on the wafer 200 to form a silicon layer. Under conditions where the HCD gas and DCS gas are not self-decomposed, the chemical adsorption layer of HCD gas and DCS gas is formed by the chemical adsorption of the HCD gas and DCS gas on the wafer 200. When the thickness of the silicon-containing layer formed on the wafer 200 exceeds several atomic layers, the oxidation action in step 3 described later does not reach the entire silicon-containing layer. The minimum value of the silicon-containing layer that can be formed on the wafer 200 is less than one atomic layer. Therefore, the thickness of the silicon-containing layer is preferably less than one atomic layer to several atomic layers.

As the first raw material containing silicon, in addition to inorganic raw materials such as HCD, aminosilane-based 4DMAS (tetrakisdimethylaminosilane, Si [N (CH ₃ ) ₂ ] ₄ ), 3DMAS (trisdimethylaminosilane, Si [N (CH _{3) 2] 3 H),} 2DEAS ( bis diethylamino _{silane, Si [N (C 2 H} 5) 2] 2 H 2), BTBAS ( Bicester tertiary butyl amino _{silane, SiH 2 [NH (C 4} H 9)] 2) Organic raw materials such as may be used. In addition to DCS, inorganic materials such as TCS (tetrachlorosilane, SiCl ₄ ), SiH ₄ (monosilane), Si ₂ H ₆ (disilane) may be used as the second material containing silicon.

As the inert gas, a rare gas such as Ar, He, Ne, or Xe may be used in addition to the N ₂ gas. Note that the use of a rare gas such as Ar or He that does not contain nitrogen (N) as the inert gas can reduce the N impurity concentration in the formed silicon oxide film. Therefore, it is preferable to use a rare gas such as Ar or He as the inert gas. The same can be said for steps 2, 3, and 4 described later.

[Step 2]
After the silicon-containing layer is formed on the wafer 200, the valve 243e of the third gas supply pipe 232c is closed, and the supply of HCD gas is stopped. Further, the valve 243g of the fourth gas supply pipe 232d is closed, and the supply of DCS gas is stopped. At this time, the APC valve 242 of the exhaust pipe 231 is kept open, the inside of the processing chamber 201 is evacuated by the vacuum pump 246, and the remaining HCD gas and DCS gas are removed from the processing chamber 201. At this time, if the inert gas is supplied into the processing chamber 201, the effect of removing the remaining HCD gas and DCS gas is further enhanced (residual gas removal). The temperature of the heater 207 at this time is set so that the temperature of the wafer 200 is 350 to 850 ° C., preferably 400 to 700 ° C., as in the case of supplying the HCD gas and the DCS gas.

[Step 3]
After the residual gas in the processing chamber 201 is removed, the valve 243a of the first gas supply pipe 232a and the valve 243c of the first inert gas supply pipe 234a are opened, and O ₂ gas and the first inert gas are supplied to the first gas supply pipe 232a. An inert gas is allowed to flow through the active gas supply pipe 234a. The inert gas flows from the first inert gas supply pipe 234a, and the flow rate is adjusted by the mass flow controller 241c. The O ₂ gas flows from the first gas supply pipe 232a and the flow rate is adjusted by the mass flow controller 241a. The O ₂ gas whose flow rate has been adjusted is mixed with the inert gas whose flow rate has been adjusted in the first gas supply pipe 232a, and is heated from the gas supply hole 248a of the first nozzle 233a into the heated processing chamber 201 in a reduced pressure state. Is exhausted from the exhaust pipe 231.
At the same time, the valve 243b of the second gas supply pipe 232b and the valve 243d of the second inert gas supply pipe 234b are opened, the H ₂ gas is supplied to the second gas supply pipe 232b, and the inert gas is supplied to the second inert gas supply pipe 234b. Flow gas. The inert gas flows from the second inert gas supply pipe 234b, and the flow rate is adjusted by the mass flow controller 241d. The H ₂ gas flows from the second gas supply pipe 232b and the flow rate is adjusted by the mass flow controller 241b. The H ₂ gas whose flow rate has been adjusted is mixed with the inert gas whose flow rate has been adjusted in the second gas supply pipe 232b, and is heated from the gas supply hole 248b of the second nozzle 233b into the heated processing chamber 201 in a reduced pressure state. And exhausted from the exhaust pipe 231 (O ₂ and H ₂ supply). Note that the O ₂ gas and the H ₂ gas are supplied into the processing chamber 201 without being activated by plasma.

At this time, the APC valve 242 is appropriately adjusted to maintain the pressure in the processing chamber 201 at a pressure lower than atmospheric pressure, for example, in a range of 1 to 1000 Pa. The supply flow rate of O ₂ gas controlled by the mass flow controller 241a is, for example, a flow rate in the range of 1 sccm to 20000 sccm (20 slm). The supply flow rate of the H ₂ gas controlled by the mass flow controller 241b is, for example, a flow rate in the range of 1 sccm to 20000 sccm (20 slm). Note that the time for which the wafer 200 is exposed to the O ₂ gas and the H ₂ gas is, for example, a time within a range of 1 to 120 seconds. The temperature of the heater 207 is set so that the temperature of the wafer 200 becomes a temperature within a range of 350 to 1000 ° C., for example. Note that it was confirmed that the effect of improving the oxidizing power by adding H ₂ gas to the O ₂ gas under a reduced pressure atmosphere can be obtained at a temperature within this range. It has also been confirmed that if the temperature of the wafer 200 is too low, the effect of improving the oxidizing power cannot be obtained. However, in consideration of the throughput, the temperature of the wafer 200 is a temperature at which the effect of improving the oxidizing power can be obtained and is the same as that at the time of supplying the HCD gas in Step 1, that is, in Step 1 and Step 3. It is preferable to set the temperature of the heater 207 so that the temperature in the chamber 201 is kept at the same temperature. In this case, the temperature of the heater 207 is set so that the temperature of the wafer 200 in step 1 and step 3, that is, the temperature in the processing chamber 201 becomes a constant temperature in the range of 350 to 850 ° C., preferably 400 to 700 ° C. Set. Furthermore, it is more preferable that the temperature of the heater 207 is set so that the temperature in the processing chamber 201 is maintained at the same temperature in steps 1 to 4 (described later). In this case, the temperature of the heater 207 is set so that the temperature in the processing chamber 201 becomes a constant temperature in the range of 350 to 850 ° C., preferably 400 to 700 ° C., in steps 1 to 4 (described later). Incidentally, in order to obtain the effect of the oxidizing power improvement by H ₂ gas added to the O ₂ gas under a reduced pressure atmosphere, although the temperature in the processing chamber 201 is required to be 350 ° C. or higher, the temperature in the processing chamber 201 Is preferably 400 ° C. or higher, more preferably 450 ° C. or higher. If the temperature in the processing chamber 201 is 400 ° C. or higher, an oxidizing power exceeding the oxidizing power by the O ₃ oxidation treatment performed at a temperature of 400 ° C. or higher can be obtained, and the temperature in the processing chamber 201 is set to 450 ° C. or higher. For example, an oxidizing power exceeding the oxidizing power by the O ₂ plasma oxidation treatment performed at a temperature of 450 ° C. or higher can be obtained.

By supplying O ₂ gas and H ₂ gas into the processing chamber 201 under the above-described conditions, the O ₂ gas and H ₂ gas are activated and reacted with non-plasma in a heated reduced pressure atmosphere, thereby Oxidized species containing O, such as atomic oxygen, are generated. Then, an oxidation process is performed on the silicon-containing layer formed on the wafer 200 in Step 1 mainly by this oxidation species. By this oxidation treatment, the silicon-containing layer is modified into a silicon oxide layer (SiO ₂ layer, hereinafter also referred to simply as “SiO layer”).

As the oxygen-containing gas, in addition to oxygen (O ₂ ) gas, ozone (O ₃ ) gas or the like may be used. In addition, when the hydrogen-containing gas addition effect to the nitrogen monoxide (NO) gas and the nitrous oxide (N ₂ O) gas was tried in the above temperature range, the NO gas alone supply and the N ₂ O gas alone supply were performed. It was confirmed that the effect of improving the oxidizing power was not obtained. That is, it is preferable to use a nitrogen-free oxygen-containing gas (a gas that does not contain nitrogen but contains oxygen) as the oxygen-containing gas. As the hydrogen-containing gas, deuterium (D ₂ ) gas or the like may be used in addition to hydrogen (H ₂ ) gas. Note that when ammonia (NH ₃ ) gas, methane (CH ₄ ) gas, or the like is used, nitrogen (N) impurities or carbon (C) impurities may be mixed into the film. That is, as the hydrogen-containing gas, it is preferable to use a hydrogen-containing gas that does not contain other elements (a gas that does not contain other elements and contains hydrogen or deuterium). That is, as the oxygen-containing gas, at least one gas selected from the group consisting of O ₂ gas and O ₃ gas can be used, and as the hydrogen-containing gas, selected from the group consisting of H ₂ gas and D ₂ gas At least one gas can be used.

[Step 4]
After modifying the silicon-containing layer into a silicon oxide layer, the valve 243a of the first gas supply pipe 232a is closed, and the supply of O ₂ gas is stopped. Further, the valve 243b of the second gas supply pipe 232b is closed, and the supply of H ₂ gas is stopped. At this time, the APC valve 242 of the exhaust pipe 231 is kept open, the inside of the processing chamber 201 is evacuated by the vacuum pump 246, and the remaining O ₂ gas and H ₂ gas are removed from the processing chamber 201. At this time, if the inert gas is supplied into the processing chamber 201, the effect of removing the remaining O ₂ gas and H ₂ gas is further enhanced (residual gas removal). The temperature of the heater 207 at this time is set to a temperature such that the temperature of the wafer 200 is 350 to 850 ° C., preferably 400 to 700 ° C., as in the case of supplying the O ₂ gas and the H ₂ gas. .

By repeating steps 1 to 4 described above as one cycle and repeating this cycle a plurality of times, a silicon oxide film (SiO ₂ film, hereinafter simply referred to as SiO film) having a predetermined thickness can be formed on the wafer 200. I can do it.

  When a silicon oxide film having a predetermined thickness is formed, the inside of the processing chamber 201 is purged with the inert gas (purge) by supplying and exhausting the inert gas into the processing chamber 201. Thereafter, the atmosphere in the processing chamber 201 is replaced with an inert gas, and the pressure in the processing chamber 201 is returned to normal pressure (return to atmospheric pressure).

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

  In Step 1 described above, the HCD gas, which is more expensive than the DCS gas but has a short incubation time, and the DCS gas that is cheaper and has a longer incubation time than the HCD gas, the supply amount of the HCD gas is larger than the supply amount of the DCS gas. By supplying simultaneously or sequentially as trace amounts, it is possible to improve the film formation rate and shorten the processing time even in the case of film formation in a low temperature region. When DCS gas is used alone, it is possible to form a film even in a low temperature region where film formation cannot be performed. In addition, it is possible to form a film in a lower temperature region than in the past. In addition, compared with the case where the HCD gas is used alone, the raw material cost can be significantly suppressed without deteriorating the film formation controllability, and the production cost of the semiconductor device can be greatly reduced.

In Step 3 described above, O ₂ gas and H ₂ gas are reacted in a heated reduced pressure atmosphere to generate an oxidizing species containing O such as atomic oxygen, and the silicon-containing layer is formed using this oxidizing species. By performing a reforming step for reforming the silicon oxide layer, the energy of the oxidizing species separates the Si—N, Si—Cl, Si—H, and Si—C bonds contained in the silicon-containing layer. Since the energy for forming the Si—O bond is higher than the bond energy of Si—N, Si—Cl, Si—H, and Si—C, the energy required for forming the Si—O bond is converted to silicon to be oxidized. By giving to the containing layer, Si—N, Si—Cl, Si—H, and Si—C bonds in the silicon containing layer are cut off. N, H, Cl, and C from which the bond with Si has been removed are removed from the film and discharged as N ₂ , H ₂ , Cl ₂ , HCl, CO _{2, and the} like. Further, the bond of N, H, Cl, and C is cut, so that the remaining Si bonds are combined with O contained in the oxidized species to be modified into a SiO ₂ layer. The SiO ₂ film formed by the film forming sequence of this embodiment has a very low concentration of nitrogen, hydrogen, chlorine, and carbon, and a Si / O ratio that is very close to the stoichiometric composition of 0.5. It was confirmed that

In addition, when the oxidation treatment of step 3 is compared with the O ₂ plasma oxidation treatment and the O ₃ oxidation treatment, the oxidizing power of the oxidation treatment of step 3 is lower in a low temperature atmosphere at 450 ° C. or higher and 850 ° C. or lower. Confirmed to be the most powerful. To be precise, at 400 ° C. or higher and 850 ° C. or lower, the oxidizing power by the oxidation treatment in Step 3 exceeds the oxidizing power by O ₃ oxidation treatment, and at 450 ° C. or higher and 850 ° C. or lower, the oxidizing power by Step 3 oxidation treatment is It was confirmed that the oxidizing power by O ₃ oxidation treatment and O ₂ plasma oxidation treatment was exceeded. As a result, it was found that the oxidation treatment in Step 3 is very effective under such a low temperature atmosphere. Note that in the case of O ₂ plasma oxidation treatment, a plasma generator is required, and in the case of O ₃ oxidation treatment, an ozonizer is required. There are merits such as being able to do. However, in this embodiment, there is an option of using O ₃ or O ₂ plasma as the oxygen-containing gas, and the use of these gases is not denied. By adding a hydrogen-containing gas to O ₃ or O ₂ plasma, it is possible to generate oxidized species with higher energy. By performing oxidation treatment with this oxidized species, effects such as improved device characteristics are also considered. It is done.

Further, if the silicon oxide film is formed by the film forming sequence of the present embodiment, the film forming rate and the film thickness uniformity in the wafer surface are better than the case of forming the silicon oxide film by a general CVD method. It was confirmed that Note that the general CVD method refers to a method of simultaneously forming DCS and N ₂ O, which are inorganic materials, and forming a silicon oxide film (HTO (High Temperature Oxide) film) by the CVD method. . Further, it was confirmed that the concentration of impurities such as nitrogen and chlorine in the silicon oxide film formed by the film forming sequence of the present embodiment is extremely lower than that of a silicon oxide film formed by a general CVD method. Further, it was confirmed that the impurity concentration in the silicon oxide film formed by the film forming sequence of this embodiment is extremely lower than that of the silicon oxide film formed by the CVD method using an organic silicon raw material. Further, according to the film forming sequence of the present embodiment, even when an organic silicon raw material is used, the film forming rate, the film thickness uniformity in the wafer surface, and the impurity concentration in the film are good. It was confirmed.

<Other Embodiments of the Present Invention>
In the above-described embodiment, the example in which the H ₂ gas as the hydrogen-containing gas is supplied intermittently as illustrated in FIGS. 4, 5, and 6, that is, only in step 3 has been described. That is, you may make it always supply, during repeating step 1-4. Further, even when intermittently supplying the H ₂ gas, only may be supplied in step 1 and 3, it may be supplied toward the step 1-3. Moreover, you may make it supply over step 2-3, and may make it supply over step 3-4.

In Step 1, that is, by supplying H ₂ gas at the time of supplying HCD gas and DCS gas, it is conceivable that Cl in HCD gas and DCS gas is extracted, thereby improving the film formation rate and reducing Cl impurities in the film. Conceivable. In step 2, that is, after the supply of the HCD gas and the DCS gas is stopped, the supply of the H ₂ gas is started before the O ₂ gas. . Also, in step 2, that is, by starting the supply of H ₂ gas before O ₂ gas, for example, an oxide film can be selectively formed on silicon for a portion where metal and silicon are exposed. It is possible to become. Further, in Step 4, that is, after the supply of O ₂ gas is stopped and before the supply of HCD gas and DCS gas is started, the surface of the SiO layer formed in Step 3 is supplied by supplying H ₂ gas. It is conceivable that the hydrogen can be terminated and reformed so that the HCD gas and DCS gas supplied in the next step 1 can be easily adsorbed on the surface of the SiO layer.

In the above-described embodiment, the step of forming a silicon-containing layer on the substrate by supplying at least two kinds of source gases (HCD gas and DCS gas) containing silicon to the substrate; By alternately supplying the reaction gas (O ₂ gas, H ₂ gas) and the step of modifying the silicon-containing layer into the silicon oxide layer, a silicon oxide film having a predetermined film thickness (on the substrate) The example of forming the (SiO film) has been described, but the present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the scope of the invention.

(Application to SiN film formation)
For example, the present invention is also applicable to the case where a silicon nitride film having a predetermined thickness is formed on a substrate by modifying a silicon-containing layer into a silicon nitride layer instead of modifying it into a silicon oxide layer (SiN film formation). it can. In this case, a nitrogen-containing gas is used as the reaction gas. As the nitrogen-containing gas, for example, NH ₃ gas is used. In this case, the film forming flow is different from the film forming flow in the above-described embodiment only in steps 3 and 4, and the rest is the same as the film forming flow in the above-described embodiment. Hereinafter, a film forming sequence when the present invention is applied to SiN film forming will be described.

FIG. 9 shows a gas supply timing chart in a film forming sequence when the present invention is applied to SiN film forming. In this film forming sequence, a first source gas containing silicon (HCD gas) and a second source gas containing silicon (DCS gas) are used as at least two kinds of source gases containing silicon in a processing container containing a substrate. ) As a reactive gas different from the first source gas and the second source gas in the processing container, and a nitrogen-containing gas (NH ₃ gas). By alternately repeating the step of modifying the silicon-containing layer into the silicon nitride layer, a silicon nitride film having a predetermined thickness is formed on the substrate. Note that the first source gas is more reactive than the second source gas, and in the step of forming the silicon-containing layer on the substrate, the supply amount of the first source gas is changed to the supply amount of the second source gas. Less than. In FIG. 9, after supplying the HCD gas and the DCS gas simultaneously in the step of forming the silicon-containing layer on the substrate, the supply of the HCD gas is stopped first, and the supply of the DCS gas alone is continued for a predetermined time. In this example, the HCD gas supply time is made shorter than the DCS gas supply time. In this case, wafer charge, boat load, pressure adjustment, temperature adjustment, step 1, step 2, purge, return to atmospheric pressure, boat unload, and wafer discharge are performed in the same manner as the film formation flow in the above-described embodiment. Steps 3 and 4 are performed as follows.

[Step 3]
After the residual gas in the processing chamber 201 is removed, the valve 243b of the second gas supply pipe 232b and the valve 243d of the second inert gas supply pipe 234b are opened, and the NH ₃ gas and the second inert gas are supplied to the second gas supply pipe 232b. An inert gas is caused to flow through the active gas supply pipe 234b. The inert gas flows from the second inert gas supply pipe 234b, and the flow rate is adjusted by the mass flow controller 241d. The NH ₃ gas flows from the second gas supply pipe 232b and the flow rate is adjusted by the mass flow controller 241b. The NH ₃ gas whose flow rate has been adjusted is mixed with the inert gas whose flow rate has been adjusted in the second gas supply pipe 232b, and is heated from the gas supply hole 248b of the second nozzle 233b into the heated processing chamber 201 in a reduced pressure state. And exhausted from the exhaust pipe 231 (NH ₃ supply). Note that the NH ₃ gas is supplied into the processing chamber 201 without being activated by plasma.

At this time, the APC valve 242 is appropriately adjusted to maintain the pressure in the processing chamber 201 at a pressure lower than atmospheric pressure, for example, in a range of 10 to 3000 Pa. The supply flow rate of the NH ₃ gas controlled by the mass flow controller 241b is, for example, a flow rate in the range of 10 sccm to 10000 sccm (10 slm). The time for exposing the wafer 200 to the NH ₃ gas is set to a time within the range of 1 to 120 seconds, for example. The temperature of the heater 207 is set so that the temperature of the wafer 200 is, for example, 350 to 850 ° C., preferably 400 to 700 ° C. Since NH ₃ gas has a high reaction temperature and does not easily react at the wafer temperature as described above, it can be thermally activated by setting the pressure in the processing chamber 201 to a relatively high pressure as described above. Yes. Note that the NH ₃ gas can generate a soft reaction by being activated by heat rather than being activated by plasma, and nitridation described later can be performed softly.

At this time, the gas flowing in the processing chamber 201 is NH ₃ gas thermally activated by non-plasma, and neither the HCD gas nor the DCS gas is flowing in the processing chamber 201. Accordingly, the NH ₃ gas does not cause a gas phase reaction, and the activated NH ₃ gas reacts with the silicon-containing layer formed on the wafer 200 in Step 1. As a result, the silicon-containing layer is nitrided and modified into a silicon nitride layer (Si ₃ N ₄ layer, also simply referred to as an SiN layer hereinafter).

As the nitrogen-containing gas, N ₂ H ₄ gas or N ₃ H ₈ gas may be used in addition to NH ₃ gas.

[Step 4]
After modifying the silicon-containing layer into the silicon nitride layer, the valve 243b of the second gas supply pipe 232b is closed, and the supply of NH ₃ gas is stopped. At this time, the APC valve 242 of the exhaust pipe 231 is kept open, the inside of the processing chamber 201 is evacuated by the vacuum pump 246, and the remaining NH ₃ gas is removed from the processing chamber 201. At this time, if an inert gas is supplied into the processing chamber 201, the effect of removing the remaining NH ₃ gas is further enhanced (residual gas removal). The temperature of the heater 207 at this time is set to such a temperature that the temperature of the wafer 200 is 350 to 850 ° C., preferably 400 to 700 ° C., as in the case of supplying the NH ₃ gas.

By repeating steps 1 to 4 described above as one cycle and repeating this cycle a plurality of times, a silicon nitride film (Si ₃ N ₄ film, hereinafter simply referred to as SiN film) having a predetermined thickness is formed on the wafer 200. I can do it.

(Application to SiON film formation)
Further, for example, in the present invention, when a silicon oxynitride film having a predetermined thickness is formed on a substrate by modifying the silicon-containing layer into a silicon oxynitride layer instead of modifying the silicon oxide layer (SiON film formation). It can also be applied to. In this case, nitrogen-containing gas and oxygen-containing gas are used as the reaction gas. As the nitrogen-containing gas, for example, NH ₃ gas is used. For example, O ₂ gas is used as the oxygen-containing gas. In this case, the film forming flow is different from the film forming flow in the above-described embodiment only in steps 3 and 4, and the rest is the same as the film forming flow in the above-described embodiment. Hereinafter, a film forming sequence when the present invention is applied to SiON film forming will be described.

FIG. 10 shows a gas supply timing chart in the film forming sequence when the present invention is applied to SiON film forming. In this film forming sequence, a first source gas containing silicon (HCD gas) and a second source gas containing silicon (DCS gas) are used as at least two kinds of source gases containing silicon in a processing container containing a substrate. ) As a reactive gas different from the first source gas and the second source gas in the processing container, and a nitrogen-containing gas (NH ₃ gas). As a reaction gas different from the first source gas and the second source gas in the process vessel and the step of modifying the silicon-containing layer into a silicon nitride layer by supplying the oxygen-containing gas (O ₂ gas) By alternately repeating the step of modifying the silicon nitride layer into a silicon oxynitride layer, a silicon oxynitride film having a predetermined thickness is formed on the substrate. Note that the first source gas is more reactive than the second source gas, and in the step of forming the silicon-containing layer on the substrate, the supply amount of the first source gas is changed to the supply amount of the second source gas. Less than. In FIG. 10, after the HCD gas and the DCS gas are simultaneously supplied in the step of forming the silicon-containing film on the substrate, the supply of the HCD gas is stopped first, and the supply of the DCS gas alone is continued for a predetermined time. In this example, the HCD gas supply time is made shorter than the DCS gas supply time. In this case, wafer charge, boat load, pressure adjustment, temperature adjustment, step 1, step 2, purge, return to atmospheric pressure, boat unload, and wafer discharge are performed in the same manner as the film formation flow in the above-described embodiment. Steps 3 and 4 are performed in place of the following steps 3, 4, 5, and 6.

[Step 3]
Step 3 is performed in the same manner as Step 3 in the application to the SiN film formation described above.

[Step 4]
Step 4 is performed in the same manner as Step 4 in the application to the SiN film formation described above.

[Step 5]
After the residual gas in the processing chamber 201 is removed, the valve 243a of the first gas supply pipe 232a and the valve 243c of the first inert gas supply pipe 234a are opened, and O ₂ gas and the first inert gas are supplied to the first gas supply pipe 232a. An inert gas is allowed to flow through the active gas supply pipe 234a. The inert gas flows from the first inert gas supply pipe 234a, and the flow rate is adjusted by the mass flow controller 241c. The O ₂ gas flows from the first gas supply pipe 232a and the flow rate is adjusted by the mass flow controller 241a. The O ₂ gas whose flow rate has been adjusted is mixed with the inert gas whose flow rate has been adjusted in the first gas supply pipe 232a, and is heated from the gas supply hole 248a of the first nozzle 233a into the heated processing chamber 201 in a reduced pressure state. Is exhausted from the exhaust pipe 231.

At this time, the APC valve 242 is appropriately adjusted to maintain the pressure in the processing chamber 201 at a pressure lower than atmospheric pressure, for example, in a range of 10 to 1000 Pa. The supply flow rate of O ₂ gas controlled by the mass flow controller 241a is, for example, a flow rate in the range of 1 sccm to 20000 sccm (20 slm). The time for exposing the wafer 200 to the O ₂ gas is, for example, a time within a range of 1 to 120 seconds. The temperature of the heater 207 is set so that the temperature of the wafer 200 is, for example, 350 to 850 ° C., preferably 400 to 700 ° C. Than O ₂ gas are activated in a plasma, who were activated by heat, the activating amount is suppressed, it is possible to suppress the oxidation of the SiN layer, so that it is possible to produce a soft reaction become.

At this time, the gas flowing in the processing chamber 201 is O ₂ gas thermally activated by non-plasma, and no HCD gas, DCS gas, or NH ₃ gas is flowing in the processing chamber 201. Therefore, the O ₂ gas does not cause a gas phase reaction, and the activated O ₂ gas reacts with the SiN layer formed on the wafer 200 in step 3. As a result, the SiN layer is nitrided and modified into a silicon oxynitride layer (SiON layer).

As the oxygen-containing gas, in addition to O ₂ gas, O ₃ gas, NO gas, N ₂ O ₄ gas, N ₂ O gas, H ₂ O gas, or the like may be used. Further, as in step 3 in the above-described embodiment, a gas obtained by adding a hydrogen-containing gas to an oxygen-containing gas may be used.

[Step 6]
After modifying the SiN layer into a silicon oxide layer, the valve 243a of the first gas supply pipe 232a is closed, and the supply of O ₂ gas is stopped. At this time, the APC valve 242 of the exhaust pipe 231 is kept open, the inside of the processing chamber 201 is evacuated by the vacuum pump 246, and the remaining O ₂ gas is removed from the inside of the processing chamber 201. At this time, if an inert gas is supplied into the processing chamber 201, the effect of removing the remaining O ₂ gas is further enhanced (residual gas removal). The temperature of the heater 207 at this time is set to such a temperature that the temperature of the wafer 200 is in the range of 350 to 850 ° C., preferably 400 to 700 ° C., as in the case of supplying the O ₂ gas.

  By repeating steps 1 to 6 described above as one cycle and repeating this cycle a plurality of times, a silicon oxynitride film having a predetermined thickness can be formed on the wafer 200.

In addition, in the application to the above-described SiON film formation, a step (step of forming a silicon-containing layer on the substrate by supplying at least two kinds of source gases (HCD gas and DCS gas) containing silicon to the substrate. 1), a step of modifying the silicon-containing layer into a silicon nitride layer by supplying a reactive gas (NH ₃ gas) to the substrate (step 3), and a reactive gas (O ₂ gas) for the substrate An example of forming a silicon oxynitride film having a predetermined thickness on the substrate by alternately repeating the step of modifying the silicon nitride layer into a silicon oxynitride layer by supplying (Step 5) However, step 3 (and 4) and step 5 (and 6) may be interchanged. That is, by supplying at least two kinds of source gases (HCD gas and DCS gas) containing silicon to the substrate, a step of forming a silicon-containing layer on the substrate (step 1) and a reaction gas for the substrate (O ₂ gas) is supplied to modify the silicon-containing layer into a silicon oxide layer (step 5), and a reactive gas (NH ₃ gas) is supplied to the substrate to thereby change the silicon oxide layer. A silicon oxynitride film having a predetermined thickness may be formed on the substrate by alternately repeating the step of modifying the silicon oxynitride layer (step 3).

In the above-described embodiment, the first source gas containing silicon (HCD gas) and the second source gas containing silicon (DCS gas) are used as at least two kinds of source gases containing silicon as the predetermined element. Although the example of using was demonstrated, you may make it use 3 or more types of source gas containing a silicon | silicone. For example, a first source gas containing silicon (HCD gas), a second source gas containing silicon (DCS gas), and a third source gas containing silicon (SiCl ₄ gas (hereinafter referred to as TCS gas)) May be used. In this case, the first source gas (HCD gas) is more reactive than the second source gas (DCS gas), and the second source gas (DCS gas) is higher than the third source gas (TCS gas). In the step of forming the silicon-containing layer on the substrate with high reactivity, the supply amount of the first source gas is made smaller than the supply amount of the second source gas and more than the supply amount of the third source gas. Less. That is, the supply amount of the source gas having the highest reactivity is made smaller than the supply amounts of the other source gases. Thereby, the same effect as the above-mentioned embodiment is obtained.

(Application to metal oxide film, metal nitride film or metal oxynitride film)
Further, the present invention uses titanium (Ti), zirconium (Zr), hafnium (Hf), aluminum (Al), etc. as the predetermined element instead of using a source gas containing a semiconductor element such as silicon (Si) as the predetermined element. By using a source gas containing the above metal element, the present invention can also be applied to the case where a metal oxide film, metal nitride film, or metal oxynitride film having a predetermined thickness is formed on a substrate.

  For example, in the case of forming a metal oxide film, a first source gas containing a metal element and a metal element are included as at least two kinds of source gases containing a metal element as a predetermined element in a processing container containing a substrate. A step of forming a metal-containing layer as a predetermined element-containing layer on the substrate by supplying the second source gas, and a reaction gas different from the first source gas and the second source gas in the processing vessel As described above, by alternately supplying the oxygen-containing gas or the step of reforming the metal-containing layer into the metal oxide layer by supplying the oxygen-containing gas and the hydrogen-containing gas, a metal having a predetermined film thickness is formed on the substrate. An oxide film is formed.

  For example, in the case of forming a metal nitride film, a first source gas containing a metal element and a metal element are used as at least two kinds of source gases containing a metal element as a predetermined element in a processing container containing a substrate. A nitrogen-containing gas as a reactive gas different from the first source gas and the second source gas in the processing vessel by supplying the second source gas containing the step of forming the metal-containing layer on the substrate The step of reforming the metal-containing layer into the metal nitride layer is alternately repeated to form a metal nitride film having a predetermined thickness on the substrate.

  In addition, for example, when forming a metal oxynitride film, a first source gas containing a metal element and a metal element are used as at least two types of source gases containing a metal element as a predetermined element in a processing container containing a substrate. And a step of forming a metal-containing layer on the substrate by supplying a second source gas containing a nitrogen-containing reaction gas different from the first source gas and the second source gas in the processing vessel. The step of reforming the metal-containing layer into a metal nitride layer by supplying a gas, and a reactive gas different from the first source gas and the second source gas in the processing vessel are oxygen-containing gas or oxygen By supplying the containing gas and the hydrogen-containing gas, the step of modifying the metal nitride layer into the metal oxynitride layer is alternately repeated to form a metal oxynitride film having a predetermined thickness on the substrate.

  In any case, the first source gas is more reactive than the second source gas, and in the step of forming the metal-containing layer on the substrate, the supply amount of the first source gas is changed to the second source gas. Less than the gas supply. That is, the supply flow rate of the first source gas is made smaller than the supply flow rate of the second source gas, the supply time of the first source gas is made shorter than the supply time of the second source gas, or By making the supply flow rate of the first source gas smaller than the supply flow rate of the second source gas and making the supply time of the first source gas shorter than the supply time of the second source gas, The supply amount of the source gas is made smaller than that of the second source gas.

For example, using a source gas containing titanium as a source gas containing a metal element, a metal oxide film, a metal nitride film, or a metal oxynitride film having a predetermined thickness on the substrate, respectively, a titanium oxide film (TiO ₂ film), titanium When forming a nitride film (TiN film) or a titanium oxynitride film (TiON film), for example, TDMAT (tetrakisdimethylaminotitanium, Ti [ N (CH ₃ ) ₂ ] ₄ ) gas and TiCl ₄ (titanium tetrachloride) gas are used. As the oxygen-containing gas, hydrogen-containing gas, and nitrogen-containing gas, the gas exemplified in the above-described embodiment can be used. In these cases, the processing temperature (substrate temperature) is set to a temperature in the range of 100 to 500 ° C., the processing pressure (pressure in the processing chamber) is set to a pressure in the range of 1 to 3000 Pa, for example, and the TDMAT gas is supplied. The flow rate is set to a flow rate in the range of 1 to 500 sccm, for example, and the supply flow rate of the TiCl ₄ gas is set to a flow rate in the range of 1 to 5000 sccm, for example. The supply flow rates of the oxygen-containing gas, hydrogen-containing gas, and nitrogen-containing gas are set to the flow rates within the ranges exemplified in the above-described embodiments. Incidentally, higher in reactivity than the TiCl ₄ gas TDMAT gas, i.e., TiCl ₄ thermal decomposition temperature is lower than the gas easily adsorbed onto the substrate than the TiCl ₄ gas under the same conditions. In the step of forming the titanium-containing layer as the metal-containing layer on the substrate, the supply amount of the TDMAT gas is made smaller than the supply amount of the TiCl ₄ gas.

Further, for example, using a source gas containing zirconium as a source gas containing a metal element, a zirconium oxide film (ZrO ₂ film) as a metal oxide film, metal nitride film or metal oxynitride film having a predetermined thickness on the substrate, When forming a zirconium nitride film (ZrN film) or a zirconium oxynitride film (ZrON film), as the first source gas containing zirconium and the second source gas containing zirconium, for example, TEMAZ (tetrakisethylmethylamino zirconium, Zr [N (CH ₃ ) C ₂ H ₅ ] ₄ ) gas, ZrCl ₄ (zirconium tetrachloride) gas is used. As the oxygen-containing gas, hydrogen-containing gas, and nitrogen-containing gas, the gas exemplified in the above-described embodiment can be used. In these cases, the processing temperature (substrate temperature) is set to a temperature in the range of 100 to 400 ° C., the processing pressure (pressure in the processing chamber) is set to a pressure in the range of 1 to 1000 Pa, for example, and the TEMAZ gas is supplied. The flow rate is set to a flow rate in the range of 1 to 500 sccm, and the supply flow rate of the ZrCl ₄ gas is set to a flow rate in the range of 1 to 5000 sccm. The supply flow rates of the oxygen-containing gas, hydrogen-containing gas, and nitrogen-containing gas are set to the flow rates within the ranges exemplified in the above-described embodiments. Incidentally, who TEMAZ gas more reactive than ZrCl ₄ gas, i.e., ZrCl ₄ thermal decomposition temperature is lower than the gas easily adsorbed onto the substrate than the ZrCl ₄ gas under the same conditions. In the step of forming the zirconium-containing layer as the metal-containing layer on the substrate, the supply amount of the TEMAZ gas is made smaller than the supply amount of the ZrCl ₄ gas.

Further, for example, using a source gas containing hafnium as a source gas containing a metal element, a hafnium oxide film (HfO ₂ film) as a metal oxide film, metal nitride film or metal oxynitride film having a predetermined thickness on the substrate, When a hafnium nitride film (HfN film) or a hafnium oxynitride film (HfON film) is formed, for example, TEMAH (tetrakisethylmethylaminohafnium, Hf [N (CH ₃ ) C ₂ H ₅ ] ₄ ) gas or HfCl ₄ (hafnium tetrachloride) gas is used. As the oxygen-containing gas, hydrogen-containing gas, and nitrogen-containing gas, the gas exemplified in the above-described embodiment can be used. In these cases, the processing temperature (substrate temperature) is set to a temperature in the range of 100 to 400 ° C., the processing pressure (pressure in the processing chamber) is set to a pressure in the range of 1 to 1000 Pa, for example, and the TEMAH gas is supplied. The flow rate is set to a flow rate in the range of 1 to 500 sccm, and the supply flow rate of the HfCl ₄ gas is set to a flow rate in the range of 1 to 5000 sccm. The supply flow rates of the oxygen-containing gas, hydrogen-containing gas, and nitrogen-containing gas are set to the flow rates within the ranges exemplified in the above-described embodiments. Incidentally, who TEMAH gas more reactive than HfCl ₄ gas, i.e., HfCl ₄ thermal decomposition temperature is lower than the gas easily adsorbed onto the substrate than HfCl ₄ gas under the same conditions. In the step of forming the hafnium-containing layer as the metal-containing layer on the substrate, the supply amount of the TEMAH gas is made smaller than the supply amount of the HfCl ₄ gas.

Further, for example, a source gas containing aluminum is used as a source gas containing a metal element, and an aluminum oxide film (Al ₂ O ₃ film) is formed on the substrate as a metal oxide film, metal nitride film, or metal oxynitride film having a predetermined thickness. ), An aluminum nitride film (AlN film) or an aluminum oxynitride film (AlON film), for example, TMA (trimethylaluminum, Al) is used as the first source gas containing aluminum and the second source gas containing aluminum, respectively. (CH ₃ ) ₃ ) gas, AlCl ₃ (aluminum trichloride) gas is used. As the oxygen-containing gas, hydrogen-containing gas, and nitrogen-containing gas, the gas exemplified in the above-described embodiment can be used. In these cases, the processing temperature (substrate temperature) is set to a temperature in the range of 100 to 400 ° C., the processing pressure (pressure in the processing chamber) is set to a pressure in the range of 1 to 1000 Pa, for example, and TMA gas is supplied. The flow rate is set to a flow rate in the range of 1 to 500 sccm, and the supply flow rate of the AlCl ₃ gas is set to a flow rate in the range of 1 to 5000 sccm. The supply flow rates of the oxygen-containing gas, hydrogen-containing gas, and nitrogen-containing gas are set to the flow rates within the ranges exemplified in the above-described embodiments. Incidentally, who TMA gas more reactive than AlCl ₃ gas, i.e., AlCl ₃ thermal decomposition temperature is lower than the gas easily adsorbed onto the substrate than the AlCl ₃ gas under the same conditions. In the step of forming the aluminum-containing layer as the metal-containing layer on the substrate, the supply amount of the TMA gas is made smaller than the supply amount of the AlCl ₃ gas.

  A silicon oxide film was formed on the wafer by the film forming sequence shown in FIG. 4 of the present embodiment, and the film forming speed (SiO film forming speed) and the in-plane film thickness uniformity (SiO film thickness uniformity) were measured. Film formation conditions (processing conditions at each step) other than the HCD flow rate and the DCS flow rate were set within the processing condition ranges described in the above-described embodiments. The DCS flow rate is fixed to a certain flow rate within the range of 1 to 2 slm, the HCD flow rate is changed within the range of 0 to 0.2 slm, and the HCD / DCS flow rate ratio is set to (A) 0%, (B) 3%, (C) 6% and (D) 10%. Hereinafter, these will be referred to as a flow rate condition (A), a flow rate condition (B), a flow rate condition (C), and a flow rate condition (D). In addition, the HCD / DCS flow rate ratio of flow rate condition (A): 0% indicates a case where HCD is not added to DCS (a case where DCS is supplied alone). In this embodiment, since the supply time of HCD and the supply time of DCS are the same, the HCD / DCS flow rate ratio is the same value as the ratio of the supply amount of HCD gas to the supply amount of DCS gas (HCD / DCS). It becomes.

  The results are shown in FIGS. 11 and 12 show the relationship between the HCD / DCS flow rate ratio and the SiO film forming rate, and the relationship between the HCD / DCS flow rate ratio and the SiO film thickness uniformity, respectively. 11 and 12 both indicate the HCD / DCS flow rate ratio (%), and the vertical axis in FIG. 11 indicates the SiO film formation rate (arbitrary unit (au)), and FIG. The vertical axis represents SiO film thickness uniformity (au). In FIG. 11, the film formation rate when the silicon oxide film is formed by supplying the HCD independently at a flow rate higher than the HCD flow rate in the flow rate condition (D) is 1 (reference). In this case, the film formation rate ratio is shown. In FIG. 12, the film thickness uniformity is 1 (reference) when the silicon oxide film is formed by supplying HCD independently at a flow rate higher than the HCD flow rate in the flow rate condition (D). ) And the film thickness uniformity ratio. The film thickness uniformity indicates the degree of variation in the film thickness distribution in the substrate surface, and the smaller the value, the better the film thickness uniformity in the substrate surface.

  From FIG. 11, an increase in the film formation rate is observed with an increase in the HCD / DCS flow rate ratio, that is, an increase in the amount of HCD added to the DCS, and the film formation rate is saturated when the HCD / DCS flow rate ratio is 6% or more. I understand that. This is because, under the processing conditions in the present embodiment, the addition of HCD to DCS compensates for DCS adsorption / deposition on the substrate, and the HCD / DCS flow rate ratio is set to 6% or more, so that DCS and HCD. This is thought to be due to saturation of adsorption / deposition on the substrate. When the HCD / DCS flow rate ratio is set to 3% or more, the adsorption / deposition of DCS and HCD on the substrate is not saturated, but the film forming rate is higher than that in the case of supplying DCS alone. Moreover, FIG. 12 shows that favorable film thickness uniformity is obtained under any flow rate conditions. In particular, it can be seen that better film thickness uniformity can be obtained by setting the HCD / DCS flow rate ratio to 6% or more. That is, it can be said that the HCD / DCS flow rate ratio is preferably 3% or more, and more preferably 6% or more, from the viewpoint of securing the film forming speed and film thickness uniformity. If the HCD / DCS flow rate ratio is greater than 50%, the potential for increasing by-products and particles increases. The raw material cost reduction effect is also reduced. For these reasons, the HCD / DCS flow rate ratio is preferably 3% to 50%, more preferably 6% to 50%. As described above, since the HCD supply time and the DCS supply time are the same in the present embodiment, the HCD / DCS flow rate ratio (HCD gas flow rate / DCS gas flow rate) is HCD / DCS (HCD gas supply). Amount / DCS gas supply amount). That is, from this example, the ratio of the supply amount of HCD gas to the supply amount of DCS gas (HCD / DCS) is preferably 3% to 50%, more preferably 6% to 50%. It can be said that it is preferable.

<Preferred embodiment of the present invention>
Hereinafter, preferred embodiments of the present invention will be additionally described.

According to one aspect of the invention,
Carrying a substrate into a processing container;
Forming a predetermined element-containing layer on the substrate by supplying and exhausting a first source gas containing a predetermined element and a second source gas containing the predetermined element in the processing container; and the processing Modifying the predetermined element-containing layer into an oxide layer, a nitride layer, or an oxynitride layer by supplying and exhausting a reactive gas different from the first source gas and the second source gas into the container; and , And alternately performing a process of forming an oxide film, a nitride film or an oxynitride film having a predetermined thickness on the substrate;
And a step of carrying out the processed substrate from the processing container,
The first source gas is more reactive than the second source gas,
In the step of forming the predetermined element-containing layer, a method for manufacturing a semiconductor device is provided in which the supply amount of the first source gas is less than the supply amount of the second source gas.

  Preferably, in the step of forming the predetermined element-containing layer, the supply flow rate of the first source gas is made smaller than the supply flow rate of the second source gas.

  Preferably, in the step of forming the predetermined element-containing layer, the supply time of the first source gas is shorter than the supply time of the second source gas.

  Preferably, in the step of forming the predetermined element-containing layer, a ratio of the supply amount of the first raw material gas to the supply amount of the second raw material gas is 3% or more and 50% or less.

  Preferably, in the step of forming the predetermined element-containing layer, a ratio of the supply amount of the first source gas to the supply amount of the second source gas is set to 6% to 50%.

  Preferably, in the step of forming the predetermined element-containing layer, the supply of the first source gas is stopped before the supply of the second source gas is stopped.

Preferably, in the step of forming the predetermined element-containing layer, the supply of the first source gas and the supply of the second source gas are started simultaneously, and the supply of the second source gas is stopped. First, the supply of the first source gas is stopped.

  Preferably, in the step of forming the predetermined element-containing layer, the supply of the first source gas is started before the supply of the second source gas is started.

  Preferably, in the step of forming the predetermined element-containing layer, the supply of the first source gas is started before the supply of the second source gas is started, and the second source gas is supplied. Prior to stopping the supply, the supply of the first source gas is stopped.

  Preferably, the predetermined element is a semiconductor element or a metal element.

According to another aspect of the invention,
Carrying a substrate into a processing container;
Forming a silicon-containing layer on the substrate by supplying and exhausting a first source gas containing silicon and a second source gas containing silicon in the processing vessel; and Modifying the silicon-containing layer into a silicon oxide layer, a silicon nitride layer, or a silicon oxynitride layer by supplying and exhausting a reactive gas different from the first source gas and the second source gas; A process of forming a silicon oxide film, a silicon nitride film, or a silicon oxynitride film having a predetermined film thickness on the substrate by repeating alternately;
And a step of carrying out the processed substrate from the processing container,
The first source gas is more reactive than the second source gas,
In the step of forming the silicon-containing layer, a method of manufacturing a semiconductor device is provided in which the supply amount of the first source gas is less than the supply amount of the second source gas.

  Preferably, in the step of forming the silicon-containing layer, the supply flow rate of the first source gas is made smaller than the supply flow rate of the second source gas.

  Preferably, in the step of forming the silicon-containing layer, the supply time of the first source gas is made shorter than the supply time of the second source gas.

  Preferably, in the step of forming the silicon-containing layer, a ratio of the supply amount of the first source gas to the supply amount of the second source gas is set to 3% or more and 50% or less.

  Preferably, in the step of forming the silicon-containing layer, a ratio of the supply amount of the first source gas to the supply amount of the second source gas is set to 6% or more and 50% or less.

  Preferably, in the step of forming the silicon-containing layer, the supply of the first source gas is stopped before the supply of the second source gas is stopped.

  More preferably, in the step of forming the silicon-containing layer, the supply of the first source gas and the supply of the second source gas are started simultaneously, and the supply of the second source gas is stopped. First, the supply of the first source gas is stopped.

  Preferably, in the step of forming the silicon-containing layer, the supply of the first source gas is started before the supply of the second source gas is started.

  Preferably, in the step of forming the silicon-containing layer, the supply of the first source gas is started and the supply of the second source gas is started before the supply of the second source gas is started. Prior to stopping the supply of the first source gas, the supply of the first source gas is stopped.

  Preferably, the first source gas is hexachlorodisilane gas, and the second source gas is dichlorosilane gas.

According to yet another aspect of the invention,
Carrying a substrate into a processing container;
A process of forming a silicon-containing layer on the substrate by supplying and exhausting hexachlorodisilane gas and dichlorosilane gas into the processing container, and supplying and exhausting a reactive gas into the processing container, The step of modifying the containing layer into a silicon oxide layer, a silicon nitride layer, or a silicon oxynitride layer is alternately repeated, whereby a silicon oxide film, a silicon nitride film, or a silicon oxynitride film having a predetermined thickness is formed on the substrate. A step of performing a forming process;
And a step of carrying out the processed substrate from the processing container,
In the step of forming the silicon-containing layer, a method of manufacturing a semiconductor device is provided in which the supply amount of the hexachlorodisilane gas is less than the supply amount of the dichlorosilane gas.

According to yet another aspect of the invention,
A processing container for containing a substrate;
A first source gas supply system for supplying a first source gas containing a predetermined element in the processing container;
A second source gas supply system for supplying a second source gas containing the predetermined element into the processing container;
A reaction gas supply system for supplying a reaction gas different from the first source gas and the second source gas into the processing container;
An exhaust system for exhausting the inside of the processing vessel;
A process of forming a predetermined element-containing layer on the substrate by supplying and exhausting the first source gas and the second source gas into the processing container containing the substrate; and in the processing container A process of modifying the predetermined element-containing layer into an oxide layer, a nitride layer, or an oxynitride layer by supplying and exhausting the reactive gas is alternately repeated, whereby an oxide film having a predetermined thickness is formed on the substrate. A control unit for controlling the first source gas supply system, the second source gas supply system, the reaction gas supply system, and the exhaust system so as to perform a process of forming a nitride film or an oxynitride film; Have
The first source gas is more reactive than the second source gas,
The controller further includes the first source gas so that the supply amount of the first source gas is less than the supply amount of the second source gas in the process of forming the predetermined element-containing layer. A substrate processing apparatus configured to control a supply system and the second source gas supply system is provided.

According to yet another aspect of the invention,
Carrying a substrate into a processing container;
A step of forming a predetermined element-containing layer on the substrate by supplying and exhausting at least two kinds of source gases containing a predetermined element in the processing vessel; and a reaction gas different from the source gas in the processing vessel By alternately supplying and exhausting the step of modifying the predetermined element-containing layer into an oxide layer, a nitride layer, or an oxynitride layer, whereby an oxide film or nitride film having a predetermined thickness is formed on the substrate. Or a process for forming an oxynitride film;
And a step of carrying out the processed substrate from the processing container,
In the step of forming the predetermined element-containing layer, there is provided a method of manufacturing a semiconductor device in which the supply amount of the most reactive source gas among the at least two kinds of source gases is less than the supply amount of other source gases. Provided.

  Preferably, in the step of forming the predetermined element-containing layer, the supply flow rate of the most reactive source gas is made smaller than the supply flow rate of the other source gas.

  Preferably, in the step of forming the predetermined element-containing layer, the supply time of the source gas having the highest reactivity is made shorter than the supply time of the other source gas.

According to yet another aspect of the invention,
Carrying a substrate into a processing container;
A process of forming a silicon-containing layer on the substrate by supplying and exhausting at least two source gases containing silicon into the processing vessel, and supplying a reaction gas different from the source gas into the processing vessel And a step of modifying the silicon-containing layer into a silicon oxide layer, a silicon nitride layer, or a silicon oxynitride layer by alternately evacuating the silicon oxide film, silicon having a predetermined thickness on the substrate A process of forming a nitride film or a silicon oxynitride film;
And a step of carrying out the processed substrate from the processing container,
In the step of forming the silicon-containing layer, a method for manufacturing a semiconductor device is provided in which the supply amount of the most reactive source gas among the at least two types of source gases is less than the supply amount of other source gases. Is done.

According to yet another aspect of the invention,
A processing vessel for processing a substrate;
A source gas supply system for supplying at least two kinds of source gases containing a predetermined element in the processing vessel;
A reaction gas supply system for supplying a reaction gas different from the source gas into the processing vessel;
An exhaust system for exhausting the inside of the processing vessel;
Supplying and exhausting the at least two kinds of source gases into the processing container containing the substrate to form a predetermined element-containing layer on the substrate; supplying the reaction gas into the processing container and exhausting By alternately repeating the process of modifying the predetermined element-containing layer into an oxide layer, a nitride layer, or an oxynitride layer, an oxide film, a nitride film, or an oxynitride film having a predetermined thickness is formed on the substrate. In the process of forming the predetermined element-containing layer, among the at least two types of source gases, the supply amount of the most reactive source gas is set to be higher than the supply amounts of other source gases. A controller that controls the source gas supply system, the reaction gas supply system, and the exhaust system,
A substrate processing apparatus is provided.

121 Controller 200 Wafer 201 Processing chamber 202 Processing furnace 203 Reaction tube 207 Heater 231 Exhaust tube 232a First gas supply tube 232b Second gas supply tube 232c Third gas supply tube 232d Fourth gas supply tube

Claims (9)

A step of supplying a including a first material gas to predetermined element with respect to the substrate, to the substrate, wherein the step of supplying a second material gas containing a predetermined element, by performing, on the substrate Forming a predetermined element-containing layer in
Modifying the predetermined element-containing layer by supplying a reactive gas different from the first source gas and the second source gas to the substrate;
The By repeating this cycle a plurality of times as one cycle, it has a step of forming a film containing a predetermined element on the substrate,
The first source gas is more reactive than the second source gas,
The method of manufacturing a semiconductor device , wherein in the step of forming the predetermined element-containing layer, the step of supplying the first source gas is stopped before the step of supplying the second source gas is stopped . 2. The method of manufacturing a semiconductor device according to claim 1, wherein in the step of forming the predetermined element-containing layer, a supply amount of the first source gas is made smaller than a supply amount of the second source gas. 3. The method of manufacturing a semiconductor device according to claim 1 , wherein in the step of forming the predetermined element-containing layer, a supply flow rate of the first source gas is made smaller than a supply flow rate of the second source gas. 4. The manufacturing of a semiconductor device according to claim 1 , wherein in the step of forming the predetermined element-containing layer, a supply time of the first source gas is made shorter than a supply time of the second source gas. Method. 5. The method according to claim 1, wherein in the step of forming the predetermined element-containing layer, a ratio of the supply amount of the first source gas to the supply amount of the second source gas is set to 3% or more and 50% or less. The manufacturing method of the semiconductor device of description. 5. The ratio of the supply amount of the first raw material gas to the supply amount of the second raw material gas is 6% to 50% in the step of forming the predetermined element-containing layer. The manufacturing method of the semiconductor device of description. 7. The method according to claim 1, wherein in the step of forming the predetermined element-containing layer, the step of supplying the first source gas is started before the step of supplying the second source gas. A method for manufacturing a semiconductor device. A step of supplying a including a first material gas to predetermined element with respect to the substrate, to the substrate, wherein the step of supplying a second material gas containing a predetermined element, by performing, on the substrate Forming a predetermined element-containing layer in
Modifying the predetermined element-containing layer by supplying a reactive gas different from the first source gas and the second source gas to the substrate;
The By repeating this cycle a plurality of times as one cycle, it has a step of forming a film containing a predetermined element on the substrate,
The first source gas is more reactive than the second source gas,
In the step of forming the predetermined element-containing layer, the substrate processing method of stopping the step of supplying the first source gas before stopping the step of supplying the second source gas . A processing container for containing a substrate;
A first source gas supply system that supplies including first source gas predetermined element into the processing chamber,
A second source gas supply system for supplying a second source gas containing a predetermined element in the processing container;
A reaction gas supply system for supplying a reaction gas different from the first source gas and the second source gas into the processing container;
By performing the process for supplying the first source gas to the substrate in the processing chamber, and a process for supplying the second source gas to the substrate in the processing chamber, said substrate The process of forming the predetermined element-containing layer thereon and the process of modifying the predetermined element-containing layer by supplying the reaction gas to the substrate in the processing container are defined as one cycle. by repeating a plurality of times, processing the line Align to form a film containing a predetermined element on the substrate, the process of forming a predetermined element-containing layer, than to stop the process for supplying the second source gas A controller configured to control the first source gas supply system, the second source gas supply system, and the reaction gas supply system so as to stop the step of supplying the first source gas first ; ,
A substrate processing apparatus.