JP2016001760A - Semiconductor device manufacturing method, substrate processing method, substrate processing apparatus and gas supply system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable deposition of a thin film of a silicon film in an amorphous state or an epitaxial state or a polysilicon state.SOLUTION: A semiconductor device manufacturing method comprises: a transfer process of transferring a substrate to a processing chamber; a first process of supplying to inside the processing chamber, a first gas containing at least a silicon element and a chlorine element; and a second process of supplying to inside the processing chamber, a second gas containing at least a silicon element of a type different from that of the first gas. By repeating the first process and the second process at least once, a silicon film in an amorphous state or an epitaxial state or a polysilicon state is formed at least on the substrate.

Description

  The present invention relates to a semiconductor device manufacturing method and a substrate processing apparatus.

  In a process of manufacturing a semiconductor device (device) such as an IC or LSI, a silicon thin film is formed on a substrate using a vertical low pressure CVD apparatus, for example, by a low pressure CVD method (chemical vapor deposition method). (For example, refer to Patent Document 1). In recent years, with the miniaturization of LSI CPU (Central Processing Unit) and DRAM (Dynamic Random Access Memory), there is an increasing demand for forming a silicon film on the upper part of the device.

International Publication No. 2006/049225 Pamphlet

On the other hand, conventionally, in order to form an amorphous or epitaxial or polysilicon state silicon film on an insulating film such as SiO ₂ , a seed layer is formed on the insulating film using silicon atoms as crystal nuclei, and then the density is high. It is necessary to form crystal nuclei and grow them as growth nuclei. However, when a silane-based gas such as monosilane (SiH ₄ ) is used alone as the source gas for the silicon film, it is difficult to form a seed layer on the insulating film, and it is difficult to form an amorphous, epitaxial, or polycrystal on the insulating film. It was difficult to form a thin silicon film in a silicon state.

  An object of the present invention is to provide a method of manufacturing a semiconductor device and a substrate processing apparatus that can form a thin film of an amorphous, epitaxial, or polysilicon silicon film on an insulating film.

  According to one aspect of the present invention, a transfer step of transferring a substrate to a processing chamber, a first step of supplying a first gas containing at least a silicon element and a chlorine element into the processing chamber, and the first step into the processing chamber. A second step of supplying a second gas containing at least a silicon element of a type different from one gas, and repeating at least one of the first step and the second step at least on the substrate Provided is a method for manufacturing a semiconductor device for forming an amorphous, epitaxial, or polysilicon silicon film.

  According to another aspect of the present invention, a processing chamber for processing a substrate, a first gas supply line for supplying a first gas containing at least silicon element and chlorine element in the processing chamber, and the first chamber in the processing chamber. A second gas supply line for supplying a second gas containing at least silicon element of a type different from one gas, a heating device for heating the processing chamber, and the heating device maintaining the heating of the processing chamber, The first gas supply line supplies the first gas into the processing chamber, the second gas supply line supplies the second gas into the processing chamber, the supply of the first gas, and the second gas A controller that controls to form an amorphous, epitaxial, or polysilicon silicon film at least on the substrate by repeating the supply at least once The substrate processing apparatus is provided with.

  According to another aspect of the present invention, a transfer step of transferring a substrate to a processing chamber, a first step of supplying at least a silane-based first gas into the processing chamber, and the first gas into the processing chamber; A second step of supplying a second gas of a different silane compound system, and repeating the first step and the second step at least once, so that at least amorphous or epitaxial on the substrate, or A method for manufacturing a semiconductor device for forming a silicon film in a polysilicon state is provided.

  According to the present invention, a thin film of an amorphous, epitaxial, or polysilicon silicon film can be formed on an insulating film.

It is front sectional drawing which shows the reactor of the CVD apparatus which concerns on one embodiment of this invention. It is a flowchart of the substrate processing process which concerns on one embodiment of this invention. It is a main gas supply time chart in the substrate processing process concerning one embodiment of the present invention. It is the schematic diagram of the film-forming which concerns on one embodiment of this invention, (a) is the growth process of the Si crystal nucleus, (b) is the mixed growth process of Si, (c) is after vapor phase reaction growth (D) is a diagram showing a growth process of an alternate film formation method of Si. It is a film-forming gas supply time chart which concerns on the 1st Embodiment of this invention. It is a film-forming gas supply time chart which concerns on the 2nd Embodiment of this invention. It is a film-forming gas supply time chart which concerns on the 3rd Embodiment of this invention. It is the film-forming gas supply time chart which concerns on the 4th Embodiment of this invention. It is the film-forming gas supply time chart which concerns on the 5th Embodiment of this invention. It is the film-forming gas supply time chart which concerns on the 6th Embodiment of this invention.

  An embodiment of the present invention will be described below.

[Configuration of substrate processing apparatus]
The substrate processing apparatus according to the present embodiment is configured as a batch type vertical hot wall type low pressure CVD apparatus (hereinafter referred to as a CVD apparatus) that forms a CVD film on a wafer in the IC manufacturing method.

(Processing room)
As shown in FIG. 1, the CVD apparatus includes a housing 2, and a standby chamber 3 for waiting for a boat 7 as a substrate processing jig is formed in the housing 2. The standby chamber 3 is preferably constructed as a sealed chamber having an airtight performance capable of maintaining a pressure lower than atmospheric pressure, and constitutes a preliminary chamber installed in the front stage of the reaction furnace 10. As a result, in the standby chamber 3, evacuation, nitrogen purge, or evacuation and nitrogen purge are repeated to remove oxygen, moisture, etc., and the standby chamber 3 passes through the standby chamber 3 from which these oxygen, moisture, etc. have been removed. Since the substrate is introduced into the reaction furnace 10, it is possible to reduce the influence of oxygen, moisture, etc. on the substrate.

  As shown in FIG. 1, a reaction furnace 10 for processing a wafer 6 as a substrate is installed on the housing 2 so as to face the boat loading / unloading port 8.

  The reaction furnace 10 includes a heater unit 11 as a heating device divided into 4 to 5 zones, for example, and a process tube 12 is installed inside the heater unit 11. The process tube 12 is made of quartz or silicon carbide, is formed in a cylindrical shape with the upper end closed and the lower end opened, and is arranged concentrically with the heater unit 11.

  A processing chamber 13 is constituted by the cylindrical hollow portion of the process tube 12. A manifold 14 is disposed under the process tube 12, and the process tube 12 is erected vertically on the housing 2 via the manifold 14.

  A seal cap 43 is installed on the upper surface of the lifting platform 33 via a seal ring. The seal cap 43 is configured to seal the boat loading / unloading port 8 of the housing 2 that becomes the furnace port of the processing chamber 13 through a seal ring.

(boat)
The boat 7 is configured to hold a plurality of wafers 6 (for example, 25, 50, 75, 100, 200, etc.) horizontally with their centers aligned. And the boat 7 is comprised so that it may carry in and out with the raising / lowering of the raising / lowering stand 33 by a boat elevator with respect to the process chamber 13 of the process tube 12. FIG.

(Exhaust system)
One end of an exhaust line 15 for exhausting the inside of the processing chamber 13 as an exhaust system is connected to the manifold 14. The other end of the exhaust line 15 is connected to a mechanical booster pump 16 and a dry pump 17 as vacuum pumps that evacuate the reactor 10.

(Gas supply system)
A first nozzle 18 and a second nozzle 28 for supplying various gases into the processing chamber 13 are laid vertically at, for example, a portion of the manifold 14 on the exhaust line 15 on the side opposite to the connecting portion. The first nozzle 18 and the second nozzle 28 are vertically supported by their lower ends fixed to the manifold 14.

  The first gas supply port of the first nozzle 18 extending in the arrangement direction of the wafers 6 is disposed at, for example, the upper end portion that is one end side of the processing chamber 13, and is blown out from the first gas supply port of the first nozzle 18. The gas flows through the processing chamber 13 from the upper end of the processing chamber 13.

  The second gas supply port of the second nozzle 28 extending in the wafer arrangement direction is disposed in the substrate processing region of the processing chamber 13 for processing the wafer 6, and the gas blown out from the second gas supply port of the second nozzle 28. Is configured to flow down from the substrate processing region of the processing chamber 13 through the processing chamber 13.

  The first nozzle 18 includes a silicon and chlorine gas supply line (hereinafter referred to as a first gas supply line) L1 for supplying at least a silicon element and chlorine element-containing gas (hereinafter referred to as a first gas) into the reaction furnace 10, and For example, an inert gas supply line (hereinafter referred to as a sixth gas supply line) L6 for supplying an inert gas (hereinafter referred to as a sixth gas) such as nitrogen gas is connected in parallel to the reaction furnace 10. .

  An upstream end of the first gas supply line L1 is connected to a gas supply source (hereinafter referred to as a first gas supply source) T1 for supplying a first gas, and an on-off valve is provided in the middle of the first gas supply line L1. V1 (hereinafter referred to as a first on-off valve) and a flow rate control device (hereinafter referred to as a first flow rate controller) M1 are provided in order from the first gas supply source T1 side. The first gas functions as a film forming gas.

  The upstream end of the sixth gas supply line L6 is connected to a gas supply source (hereinafter referred to as a sixth gas supply source) T6 that supplies a sixth gas, and an on-off valve is provided in the middle of the sixth gas supply line L6. V6 (hereinafter referred to as the sixth on-off valve) and a flow rate controller (hereinafter referred to as the sixth flow rate controller) M6 are sequentially provided from the sixth gas supply source T6 side. The sixth gas (inert gas) functions as a gas for purging the processing chamber 13 and the first gas supply line L1, and a carrier gas for diluting and transporting the first gas.

  The second nozzle 28 includes a silane-based gas supply line (hereinafter referred to as a 21st gas supply line) L 21 for supplying a silane-based gas (hereinafter referred to as a 21st gas) into the reaction furnace 10, and a A silane compound gas supply line (hereinafter referred to as the 22nd gas supply line) L22 for supplying a silane compound gas other than 21 gas (hereinafter referred to as the 22nd gas) L22 and a hydrogen gas (hereinafter referred to as 4th gas) in the reaction furnace 10, for example. A hydrogen gas supply line (hereinafter referred to as a fourth gas supply line) L4 and an inert gas supply for supplying an inert gas (hereinafter referred to as a fifth gas) such as nitrogen gas into the reaction furnace 10. Lines (hereinafter referred to as fifth gas supply lines) L5 are respectively connected in parallel. The 21st gas and the 22nd gas (hereinafter collectively referred to as the second gas) are gases containing at least a silicon element of a type different from the first gas. The twenty-first gas supply line L21 and the twenty-second gas supply line L22 are collectively referred to as a second gas supply line L2.

  The upstream end of the twenty-first gas supply line L21 is connected to a silane-based gas supply source T21 (hereinafter referred to as a twenty-first gas supply source), and an on-off valve (hereinafter referred to as a twenty-first valve) is provided in the middle of the twenty-first gas supply line L21. An on-off valve (V21) and a flow rate controller (hereinafter referred to as a 21st flow rate controller) M21 are sequentially provided from the 21st gas supply source T21 side. The 21st gas (silane-based gas) functions as a second pretreatment gas or a film forming gas.

  The upstream end of the twenty-second gas supply line L22 is connected to a silane compound gas supply source T22 (hereinafter referred to as the twenty-second gas supply source), and an on-off valve (hereinafter referred to as the second gas supply line L22) is provided in the middle of the twenty-second gas supply line L22. 22 on-off valve) and a flow rate controller (hereinafter referred to as a 22nd flow rate controller) M22 are provided in order from the 22nd gas supply source T22 side. The 22nd gas (silane compound gas) functions as a second pretreatment gas or a film forming gas.

  The upstream end of the fourth gas supply line L4 is connected to, for example, a gas supply source T4 (hereinafter referred to as a fourth gas supply source) that supplies hydrogen gas. Hereinafter, a fourth open / close valve (V4) and a flow rate controller (hereinafter referred to as a fourth flow rate controller) M4 are sequentially provided from the fourth gas supply source T4 side.

  An upstream end of the fifth gas supply line L5 is connected to a gas supply source T5 (hereinafter referred to as a fifth gas supply source) that supplies an inert gas such as nitrogen gas, for example, and is in the middle of the fifth gas supply line L5. Is provided with an open / close valve (referred to as a fifth open / close valve) V5 and a flow rate controller (hereinafter referred to as a fifth flow rate controller) M5 in order from the fifth gas supply source T5 side. The fifth gas (inert gas) dilutes the gas for purging the processing chamber 13 and the 21st gas supply line L21, the 22nd gas supply line L22, the 4th gas supply line L4, the 21st gas, and the 22nd gas. It functions as a carrier gas to be carried.

(controller)
The first on-off valve V1 and the first flow rate controller M1 of the first gas supply line L1, the 21st on-off valve V21 and the 21st flow rate controller M21 of the 21st gas supply line L21, and the 22nd of the 22nd gas supply line L22. On-off valve V22 and 22nd flow rate controller M22, 4th on-off valve V4 and 4th flow rate controller M4 of 4th gas supply line L4, 5th on-off valve V5 and 5th flow rate controller M5 of 5th gas supply line L5 The sixth on-off valve V6 and the sixth flow rate controller M5 of the sixth gas supply line L6 are electrically connected to the controller 19.

  Specifically, the controller 19 controls the flow rate of the flow controllers M1, M21, M22, M4, M5, and M6, and controls the open / close valves V1, V21, V22, V4, V5, and V6, respectively. Gas supply at a predetermined flow rate is started at a predetermined timing in the processing chamber 13 or gas supply is stopped. Further, the controller 19 adjusts the power supply to the heater unit 11 based on the temperature information detected by the temperature sensor so that the inside of the processing chamber 13 and the surface of the wafer 6 reach a predetermined temperature at a predetermined timing. .

  Further, the controller 19 supplies the twenty-second gas into the processing chamber 13 in the film forming process, and after supplying the twenty-second gas, supplies the twenty-first gas into the processing chamber 13 so that at least on the wafer 6. An amorphous, epitaxial, or polysilicon state silicon film may be formed.

  The controller 19 is also electrically connected to the mechanical booster pump 16, the dry pump 17, and other parts constituting the CVD apparatus. Transfer the wafer into the processing chamber 13, control the transfer means for transferring the wafer to carry the wafer out of the processing chamber 13 to the outside of the processing chamber 13, depressurize the processing chamber 13, or return to atmospheric pressure Like to do.

In some other embodiments, the controller 19 controls the fifth gas supply line L5 while heating and maintaining the inside of the processing chamber 13 before the film forming process, so that the fifth gas (inert gas) is contained in the processing chamber 13. (N ₂ gas)) may be exhausted while being supplied, and a water desorption process for desorbing moisture adhering to the inside of the processing chamber 13 may be performed. Note that the fifth gas may be continuously supplied in the processes after the water desorption process.

[Substrate processing process]
The substrate processing step as one step of the IC manufacturing method according to one embodiment of the present invention is shown in FIG. 2 in the case where a silicon film is formed on a wafer using the CVD apparatus having the above configuration. The process flow and the gas supply timing shown in FIG. 3 will be described.

(Wafer transfer process)
In the wafer transfer step (S201) shown in FIG. 2, the boat 7 supported by the lifting platform 33 rises through the seal cap 43 and is transferred into the processing chamber 13 of the process tube 12 from the boat loading / unloading port 8. (Boat loading). When the boat 7 reaches the upper limit, the periphery of the upper surface of the seal cap 43 closes the boat loading / unloading port 8 in a sealed state via the seal ring, so that the processing chamber 13 of the process tube 12 is closed in an airtight manner. Become.

(Temperature and decompression process)
After the wafer transfer, the interior of the processing chamber 13 is heated by the heater unit 11 so that the temperature in the processing chamber 13 becomes a predetermined temperature in the temperature raising and depressurization step (S203) shown in FIG. Further, the inside of the processing chamber 13 is evacuated through the exhaust line 15 by the mechanical booster pump 16 and the dry pump 17. Thereby, the pressure in the processing chamber 13 is controlled to be a pressure lower than the atmospheric pressure. Further, the boat 7 is rotated at a predetermined rotation speed.

(Water desorption process)
A water desorption step (S205) may be performed after the temperature and pressure reduction step. In this step, the sixth on-off valve V6 or the fifth on-off valve V5 is opened. The sixth gas (nitrogen gas) of the sixth gas supply source T6 or the fifth gas (nitrogen gas) of the fifth gas supply source T5 enters the sixth supply line L6, the sixth gas in the processing chamber 13 in the evacuated state. The first gas supply port of the first nozzle 18 or the second of the second nozzle 28 is passed through the on-off valve V6, the sixth flow rate controller M6, or the fifth supply line L5, the fifth on-off valve V5, and the fifth flow rate controller M5. It is supplied from the gas supply port (FIG. 3) and exhausted from the exhaust line 15. In this way, the inert gas (N ₂ gas) is supplied into the processing chamber 13 and exhausted to desorb moisture adhering to the processing chamber 13. The supply of nitrogen gas into the processing chamber 13 in the evacuated state is maintained after the water desorption process. Further, as a pretreatment, hydrogen gas may be supplied to clean the substrate surface.

(Film forming process)
Next, after stabilizing the film formation temperature and the processing pressure, in the film formation processing step (S211) shown in FIG. 2, the source gas supply of the first gas and the second gas into the processing chamber is performed at least once. Performed (FIG. 3). Here, when the source gas supply of the first gas and the second gas into the processing chamber 13 is performed at least once, the case where the first gas and the second gas are supplied back and forth, The case where the first gas and the second gas are alternately supplied is included. Note that simultaneous supply of the first gas and a second gas of a different type from the first gas may be performed in the processing chamber 13.

  These gases are controlled by the controller 19 by the first on-off valve V1, the 21st on-off valve V21, the 22nd on-off valve V22, the first flow rate controller M1, the 21st flow rate controller M21, and the 22nd flow rate controller M22. Thus, the processing chamber 13 passes through the first gas supply port of the first nozzle 18 and the second gas supply port of the second nozzle 28 via the first gas supply line L1, the 21st gas supply line L21, and the 22nd gas supply line L22. To be supplied appropriately.

In addition, as a process condition of the film-forming process (S211) which concerns on this embodiment,
Treatment temperature: room temperature to 450 ° C., preferably 350 ° C. to 450 ° C., more preferably upper limit temperature is 400 ° C. or less Treatment pressure: 13 Pa to 13330 Pa Monosilane gas (second gas) supply flow rate: 10 sccm to 2000 sccm Dichlorosilane gas ( First gas) Supply flow rate: 10 sccm or more and 2000 sccm or less is exemplified.

  In this film forming process, in addition to the silicon element-containing gas, a silicon element and chlorine element-containing gas that can be easily formed in the initial stage is used. Therefore, silicon nuclei are formed on the film formed on the wafer, for example, on the insulating film. Since a seed layer having a predetermined thickness can be formed, a silicon film in an amorphous, epitaxial, or polysilicon state is formed on the insulating film on the wafer at a pressure lower than atmospheric pressure and at a low temperature of 450 ° C. or lower. Can be easily formed. In addition, since the boat 7 is rotated during the film forming process, the source gas is uniformly brought into contact with the surface of the wafer 6, so that the insulating film on the wafer 6 is formed on the insulating film on the amorphous, epitaxial, or polycrystal. A silicon film in a silicon state is uniformly formed. Amorphous silicon films are mainly obtained by continuously supplying silicon element-containing gas (silane-based gas), and polysilicon films and epitaxial films are mainly supplied alternately with silicon element and chlorine element-containing gas and silane-based gas. Can be obtained. In general, for example, an epitaxial silicon film is obtained at 400 ° C. to 600 ° C., a polysilicon film is obtained at 400 ° C. to 650 ° C., and an amorphous silicon film is obtained at 350 ° C. to 550 ° C., respectively. The gas supply timing in the film forming process will be described in detail later with reference to FIGS.

(Cooling and atmospheric pressure recovery process)
After the elapse of a preset processing time, the first on-off valve V1, the 21st on-off valve V21, and the 22nd on-off valve V22 are closed in the temperature lowering and atmospheric pressure return step (S213) shown in FIG. Supply to the processing chamber 13 is stopped, and a cycle purge step is performed. In this cycle purge step, the fifth on-off valve V5 and the sixth on-off valve V6 are opened, and the inside of the processing chamber 13 and the inside of the first nozzle 18 and the second nozzle 28 are cycle purged with nitrogen gas. Subsequently, the temperature in the processing chamber 13 is lowered to a predetermined temperature by natural cooling, and the inside of the processing chamber 13 is returned to atmospheric pressure by supplying nitrogen gas to the processing chamber 13.

(Wafer transfer process)
After the temperature lowering and atmospheric pressure returning process, in the wafer transfer process (S215) shown in FIG. 2, the lift table 33 supporting the seal cap 43 and the boat 7 is lowered, so that the boat 7 holding the processed wafer 6 waits. Carried out to the chamber 3 (boat unloading).

  Thereafter, by repeating the above-described operation, a plurality of wafers 6 (for example, 25, 50, 75, 100, 200, etc.) are batch processed by the CVD apparatus.

  Hereinafter, the gas supply timing of the film-forming process described in detail later will be described using the first to sixth embodiments illustrated in FIGS.

(Gas supply timing of the film forming process of the first embodiment (FIG. 5))
As shown in FIG. 5, a first gas (silicon element and chlorine element-containing gas (chlorine-containing silane-based gas)) is supplied into the processing chamber 13 from the first gas supply port of the first nozzle 18 for a predetermined time. After supplying one gas, the second gas (silicon element-containing gas (silane-based gas)) is continuously supplied from the gas supply port of the second nozzle 28 into the processing chamber 13 for a time longer than the predetermined time. As shown in FIG. 4A, in order to form a silicon film on an insulating film, first, silicon atoms are formed as crystal nuclei so that the silicon film can be easily formed on the insulating film. Next, high-density crystal nuclei are formed and grown as growth nuclei. However, when a silane-based gas such as monosilane (SiH ₄ ) is used at a film forming temperature of 500 ° C. or lower, it is difficult to form the Si film on the insulating film. However, by flowing the chlorine-containing silane-based gas first, as shown in FIG. 4D, the gas species containing Cl element contributes to the initial film formation, and the seed layer containing Cl element is formed on the insulating film surface. Since the Cl element of the seed layer is formed and is replaced by Si of a silane-based gas, for example, monosilane gas (SiH ₄ ), an amorphous, epitaxial, or polysilicon silicon film is stably formed on the insulating film. To do. Here, the silicon element and chlorine element-containing gas is, for example, dichlorosilane (DCS: SiH ₂ Cl ₂ ), trichlorosilane (SiHCl ₃ ), tetrachlorosilane (SiCl ₄ ), hexachlorodisilane (HCD: Si ₂ Cl ₆ ), or the like. It is. The silicon element-containing gas different from the silicon element and chlorine gas-containing gas is, for example, any one of monosilane (SiH ₄ ), disilane (Si ₂ H ₆ ), trisilane (Si ₃ H ₈ ), and the like.

Accordingly, after introducing the chlorine-containing silicon-based gas from the first nozzle 18 into the processing chamber 13 and introducing the chlorine-containing silicon-based gas, and then introducing the silicon-based gas from the second nozzle 28, the silicon substrate surface is formed. Alternatively, after a seed layer containing a Cl element is formed on the surface of the insulating film, the Cl element is replaced with a Si element by a silane-based gas, so that the film can be formed even if it is not decomposed at a low temperature. Therefore, an amorphous, epitaxial, or polysilicon silicon film can be formed on the insulating film at a low temperature. Therefore, since film formation can be performed by non-plasma, it is not necessary to provide an expensive apparatus such as a plasma generator.
As gas supply conditions,
Monosilane gas supply flow rate: 10 sccm or more and 2000 sccm or less Dichlorosilane gas supply flow rate: 10 sccm or more and 2000 sccm or less Monosilane gas supply time: 5 seconds or more and 60 minutes or less are exemplified.

(Gas supply timing of the film forming process of the second embodiment (FIG. 6))
The second embodiment differs from the first embodiment in that supply of a silane-based gas species containing Cl element and supply of silane-based gas into the processing chamber 13 are alternately performed as shown in FIG. This is the point that is being implemented. Specifically, silane-based gas and chlorine-containing silane-based gas are alternately supplied into the processing chamber 13 from the second gas supply port of the second nozzle 28 and the first gas supply port of the first nozzle 18. It is a point. In this case, an inert gas such as N ₂ is supplied into the processing chamber 13 from the fifth gas supply line L5 and the sixth gas supply line L6 during the gas supply of the silane-based gas and the chlorine-containing silane-based gas. Thus, it is preferable to purge the source gas remaining in the second gas supply line L2, the first gas supply line L1, and the processing chamber 13. When these gases are alternately supplied using a gas species containing Cl element and a silane-based gas, as shown in FIG. 4D, a seed layer containing Cl element on the substrate surface by the gas species containing Cl element. The Cl element in the seed layer is replaced with Si of a silane-based gas, for example, monosilane gas (SiH ₄ ), and the formation and replacement of the seed layer are alternately repeated, whereby an amorphous or epitaxial layer is formed on the insulating film. Alternatively, a silicon film in a polysilicon state is stably formed at a low temperature.
At this time, it is preferable to supply the chlorine-containing silane gas first. Thereby, the natural oxide film, impurities, etc. existing on the substrate can be removed by chlorine atoms.
In FIG. 6, the gas supply time is supplied for the same time. However, the gas supply time is not limited to this, and the gas supply times may be set differently, and the gas supply timings overlap. Gas supply may be performed.

  Both the silane-based gas species containing Cl element and the silane-based gas are supplied in the range of 2 seconds to 10 minutes. When supplying two kinds of gases at different timings, by changing the flow rate and time, it is possible to stably suppress vapor phase growth under low temperature conditions and obtain a thin silicon film with good uniformity.

According to the present embodiment, after introducing the chlorine-containing silane-based gas, a seed layer containing Cl element is formed on the silicon substrate or on the insulating film, and then the Cl element is replaced with Si element by the silane-based gas. By repeating this, a film can be formed even when the gas is not easily decomposed at a low temperature.
As gas supply conditions,
Monosilane gas supply flow rate: 10 sccm to 2000 sccm Dichlorosilane gas supply flow rate: 10 sccm to 2000 sccm Monosilane gas supply time: 2 seconds to 10 minutes Dichlorosilane gas supply time: 2 seconds to 10 minutes

(Gas supply timing of the film forming process of the third embodiment (FIG. 7))
The third embodiment differs from the second embodiment in that, as shown in FIG. 7, supply of a silane-based gas species containing Cl element into the processing chamber 13, silane-based gas, and silane-based The supply of compound gas is performed. Specifically, a silane compound gas (disilane), a silane gas (monosilane), and a chlorine-containing silane gas (dichlorosilane) are alternately supplied into the processing chamber 13. In this case, an inert gas such as N ₂ is supplied into the processing chamber 13 during the supply of the silane compound gas, the silane gas, and the chlorine-containing silane gas, and the 21st gas supply line L21 and the 22nd gas are supplied. It is preferable to purge the source gas remaining in the supply line L22 and the processing chamber 13. As in the third embodiment, when these gases are alternately supplied using a Cl species-containing gas species, a silane-based gas, and a silane-based compound gas, the seed layer is insulated by the Cl species-containing gas species. The Cl element of the seed layer formed on the film is replaced with Si of a silane-based gas, for example, monosilane gas (SiH ₄ ), and the formation and replacement of the seed layer are alternately repeated, whereby the seed layer is amorphous or The silicon film in the epitaxial or polysilicon state is more stable and is formed at a lower temperature.
As gas supply conditions,
Monosilane gas supply flow rate: 10 sccm to 2000 sccm Disilane gas supply flow rate: 10 sccm to 2000 sccm Dichlorosilane gas supply flow rate: 10 sccm to 2000 sccm Monosilane gas supply time: 2 seconds to 10 minutes Disilane gas supply time: 2 seconds to 10 minutes Dichlorosilane gas supply time: Examples are 2 seconds or more and 10 minutes or less.
In this embodiment, chlorine-containing silane-based gas, silane-based gas, and silane-based compound gas are alternately supplied. However, after supplying chlorine-containing silane-based gas, silane-based gas and silane-based compound gas are simultaneously supplied. You may do it.

(Gas supply timing of the film forming process of the fourth embodiment (FIG. 8))
In the first to third embodiments described above, a chlorine-containing silane-based gas is used as one of the two types of source gases. However, in the fourth embodiment, a chlorine-containing silane-based gas is used. A case where two types of gases, ie, a silane-based gas (monosilane) and a silane-based compound gas (disilane, trisilane) are used is exemplified.

A silane compound gas is supplied into the processing chamber 13 to carry out a film forming process after the wafer on which the insulating film is formed is transferred to the processing chamber, and the silane compound gas is supplied into the processing chamber 13 after the silane compound gas is supplied. The system gas is supplied. Using a silane compound gas such as disilane (Si ₂ H ₆ ) or trisilane (Si ₃ H ₈ ) and a silane gas such as monosilane (SiH ₄ ), as shown in FIG. If the silane-based gas is supplied first and then the silane-based gas is supplied later, as shown in FIG. 4C, disilane gas, trisilane, etc. are decomposed in the gas phase to form a seed layer. When the seed layer is formed and then laminated with a silane-based gas such as monosilane gas (SiH ₄ ), an amorphous, epitaxial, or polysilicon silicon film is stably formed on the insulating film. In this film forming process, a boron-containing gas that is a p-type dopant may be supplied in order to make the silicon film to be formed conductive.

  As described above, according to the fourth embodiment, since a gas species such as disilane and trisilane that reacts in a gas phase with a metal film is selected as a source gas, a composition of 450 ° C. or less can be formed without using a chlorine-containing silane-based gas. Even at the film temperature, an amorphous, epitaxial, or polysilicon silicon film can be formed on the insulating film. Thereby, since it can implement by non-plasma, it does not need to provide expensive apparatuses, such as a plasma generator.

Monosilane gas supply flow rate: 10 sccm or more and 2000 sccm or less Disilane gas supply flow rate: 10 sccm or more and 2000 sccm or less are exemplified.

(Gas supply timing of the film forming process of the fifth embodiment (FIG. 9))
In the fifth embodiment, as shown in FIG. 9, the first gas and the second gas of a different type from the first gas (silicon element and chlorine element-containing gas) are simultaneously supplied into the processing chamber 13. As a result, a silicon film in an amorphous, epitaxial, or polysilicon state is formed on at least the wafer 6.

In this regard, these gases are supplied simultaneously using a gas species containing a chlorine element (Cl element) such as dichlorosilane (DCS: SiH ₂ Cl ₂ ) and a silane-based gas. Then, as shown in FIG. 4B, even at a film formation temperature of 500 ° C. or less, the gas species containing Cl contributes to the initial film formation, and the seed layer containing the Cl element is formed. Since the element is replaced by Si of a silane-based gas, for example, monosilane gas (SiH ₄ ), an amorphous, epitaxial, or polysilicon silicon film is stably formed on the insulating film.

  Thus, according to the fifth embodiment, by selecting a gas species containing Cl element as a gas that reacts in a gas phase even at a low temperature, an amorphous or epitaxial layer is formed on the insulating film even at a film forming temperature of 500 ° C. or lower. Alternatively, a silicon film in a polysilicon state can be formed. Further, since the film can be formed by non-plasma, it is not necessary to provide an expensive apparatus such as a plasma generator.

As gas supply conditions,
Monosilane gas supply flow rate: 50 sccm or more and 2000 sccm or less Dichlorosilane gas supply flow rate: 50 sccm or more and 2000 sccm or less is exemplified.

(Gas supply timing of the film forming process of the sixth embodiment (FIG. 10))
The sixth embodiment is similar to the fifth embodiment in that two types of gas, a silane-based gas (silicon element-containing gas) and a chlorine-containing silane-based gas (silicon element and chlorine element-containing gas) are supplied simultaneously. Although it is the same as the embodiment, the difference from the fifth embodiment is that, as shown in FIG. 10, two types of silane-based gases are used instead of one. The two types of silane-based gases are a silane-based compound gas and a silane-based gas containing a different type of silane from the compound gas. In the example of FIG. 10, disilane (Si ₂ H ₆ ), trisilane (Si ₃ H ₈ ) or the like is used as the silane compound gas, and monosilane (SiH ₄ ) or the like is used as the silane gas. Further, dichlorosilane, trichlorosilane, or the like is used as the chlorine-containing silane-based gas. According to the sixth embodiment, while the seed layer containing the Cl element is formed, the Cl element of the seed layer is replaced with the Si element of the two types of silane-based gases, so that the silicon film is formed on the insulating film. Film formation is more stable.
As gas supply conditions,
Monosilane gas supply flow rate: 50 sccm to 2000 sccm Disilane gas supply flow rate: 50 sccm to 2000 sccm Dichlorosilane gas supply flow rate: 10 sccm to 2000 sccm

[Effect of the embodiment]
According to embodiments of the present invention, one or more of the following effects are provided.

  According to the embodiment of the present invention, since the silicon element and chlorine-containing gas are used as the source gas of the silicon film, a thin film of an amorphous, epitaxial, or polysilicon silicon film is formed on the insulating film. Is possible.

  According to the embodiment of the present invention, a silicon film having a uniform silicon film thickness can be stably obtained at a low temperature of 450 ° C. or lower, more preferably 400 ° C. or lower.

  According to the embodiment of the present invention, since a silicon film can be formed by non-plasma for low temperature growth, it is not necessary to provide an expensive apparatus such as a plasma generator.

  Since the process temperature is as low as 450 ° C. or lower, it is possible to prevent the diffusion of dopants in the wiring of a conductive material part of an LSI CPU (Central Processing Unit) or DRAM (Dynamic Random Access Memory) or in a shallow junction.

  According to the embodiment of the present invention, by forming a film at a low temperature, the diffusion of the dopant is prevented, the recrystallization of the base film is prevented, and the deterioration of the electrical characteristics is prevented. Accordingly, a faster and finer LSI can be manufactured.

  According to this embodiment, since the silicon film can be formed at a low temperature, the diffusion of the dopant is prevented, the recrystallization of the base film is prevented, and the deterioration of the electrical characteristics can be prevented, that is, the low temperature silicon film, A low-temperature amorphous silicon film using a silane-based gas, a low-temperature polysilicon film obtained by alternately forming a chlorine-containing silicon-based gas, or an epitaxial or amorphous silicon film can be formed.

  With the miniaturization of semiconductor devices, there is an increasing demand for forming a film on a device such as a high-k material or a metal material. However, since a film can be formed at a low temperature of 450 ° C. or less, the high-k A silicon film can be formed at a low temperature on the upper part of the device such as a metal material or a metal material. Therefore, it is possible to suppress deterioration of logic transistors and memory capacitors using a high-k material or a metal material.

  With the miniaturization and increase in capacity of semiconductor devices, high dielectric constant (High-k) insulating materials are used for capacitive films, metals such as Cu are used for wiring, and metal materials are used for electrodes. In order to improve the performance of the device and prevent deterioration, it is essential that the process of the electrode joint is performed at a low temperature. However, according to this embodiment, the film forming process can be performed at a low temperature. I can respond.

  In mass production, film formation and film thickness stability in such a low-temperature process can be realized, so that device productivity can be improved.

  In addition, when the film is formed only with the silane-based gas, the film formation temperature exceeds 450 ° C., so that impurity diffusion into the base film and self-annealing of the film itself occur, and the deterioration of the electrical characteristics of the device becomes a problem. According to the present embodiment, film formation at 450 ° C. or lower can be realized, so that such a problem hardly occurs.

  In addition, when film formation is performed at a low temperature of 450 ° C. or less by using a highly reactive silane-based gas alone, the in-plane uniformity of the silicon film may vary by several tens of percent or more. According to the present embodiment using the contained gas, in-plane uniformity of usually 2 to 3% or less can be realized at the mass production level. Therefore, the uniformity of the silicon film thickness in the batch can be greatly improved.

(Other)
Of course, the present invention can be variously modified without departing from the scope of the invention.

For example, in this embodiment, a dopant for making a silicon film conductive is not particularly described. In a film forming process, diborane (B ₂ H ₆ ) is used as a p-type dopant in addition to a silicon film source gas. A silicon film to be formed may be made conductive by supplying a boron element-containing gas such as.

  In the present embodiment, the reaction tube is configured by a single process tube, and the gas flowing through the process tube is discharged from the exhaust line 15, but the present invention is not limited to this. For example, the reaction tube may be composed of a double tube composed of an outer tube and an inner tube, and gas may be discharged from the exhaust line 15 via a cylindrical space formed between the outer tube and the inner tube. . In this case, an exhaust hole communicating with the cylindrical space may be provided on the side wall of the inner tube.

  In this embodiment, a plurality of gas supply lines are commonly connected to the first nozzle and the second nozzle, respectively. However, the first nozzle and the second nozzle are each composed of a plurality of nozzles. A plurality of gas supply lines may be individually connected to each nozzle constituting the nozzle group.

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

  According to the first aspect, the transporting step of transporting the substrate to the processing chamber, the first step of supplying the first gas containing at least silicon element and chlorine element into the processing chamber, and the first in the processing chamber. A second step of supplying a second gas containing at least a silicon element of a type different from the gas, and by repeating the first step and the second step at least once, at least on the substrate Alternatively, a method of manufacturing a semiconductor device for forming a silicon film in an epitaxial or polysilicon state is provided.

  According to the second aspect, the processing chamber for processing the substrate, the first gas supply line for supplying the first gas containing at least silicon element and chlorine element into the processing chamber, and the first gas in the processing chamber. A second gas supply line for supplying a second gas containing at least a silicon element of a different type, a heating device for heating the processing chamber, and the heating device maintaining the heating of the processing chamber, A gas supply line supplies the first gas into the processing chamber, a second gas supply line supplies the second gas into the processing chamber, a supply of the first gas, and a supply of the second gas And a controller that controls to form at least an amorphous, epitaxial, or polysilicon silicon film on the substrate by repeating at least once. That the substrate processing apparatus is provided.

  According to the third aspect, a transporting step of transporting the substrate to the processing chamber, a first step of supplying a first gas containing at least silicon element and chlorine element into the processing chamber, and the first into the processing chamber. And a second step of supplying a second gas containing at least a silicon element of a different type from the above gas, and after repeating the first step and the second step at least once, at least silicon in the processing chamber By performing the third step of supplying a third gas containing an element, there is provided a method for manufacturing a semiconductor device that forms an amorphous, epitaxial, or polysilicon silicon film on at least the substrate. .

  According to a fourth aspect, there is provided a method for manufacturing a semiconductor device according to the first embodiment, wherein a silicon gas is contained and a third gas different from the first and second gases is simultaneously supplied.

  According to a fifth aspect, there is provided the method for manufacturing a semiconductor device according to the fourth embodiment, wherein the second gas is a silane-based gas and the third gas is a silane compound-based gas. The

According to a sixth aspect, in the first aspect,
There is provided a method for manufacturing a semiconductor device, further comprising a purge step of supplying an inert gas between the first process and the second process.

According to a seventh embodiment, in the first aspect,
A method for manufacturing a semiconductor device is provided in which the silicon film is formed at 450 ° C. or lower.

According to an eighth embodiment, in the first aspect,
In the first step, a method of manufacturing a semiconductor device performed before the second step is provided.

  According to the ninth embodiment, the transfer step of transferring the substrate to the processing chamber, the first step of supplying at least a silane-based first gas into the processing chamber, and the first gas in the processing chamber are different. A second step of supplying a silane compound-based second gas, and repeating the first step and the second step at least once, so that at least amorphous or epitaxial on the substrate, or A method for manufacturing a semiconductor device for forming a polysilicon film in a polysilicon state is provided.

1 CVD equipment (semiconductor manufacturing equipment)
6 Wafer (substrate)
7 boat (substrate processing jig)
8 Boat loading / unloading port 10 Reactor 11 Heater unit (heating device)
12 process tube 13 processing chamber 15 exhaust line 18 first nozzle 19 controller 28 second nozzle L1 first gas supply line T1 first gas supply source V1 first on-off valve M1 first flow controller L21 21st gas supply line T21 first 21 gas supply source V21 21st on-off valve M21 21st flow controller L22 22nd gas supply line T22 22nd gas supply source V22 22nd on-off valve M22 22nd flow controller L3 3rd gas supply line T3 3rd gas supply source V3 Third open / close valve M3 Third flow controller L4 Fourth gas supply line T4 Fourth gas supply source V4 Fourth open / close valve M4 Fourth flow controller L5 Fifth gas supply line T5 Fifth gas supply source V5 Fifth open / close Valve M5 Fifth flow controller L6 Sixth gas supply line T6 Sixth gas supply source V6 Sixth on-off valve M6 Sixth flow control vessel

Claims (7)

A first step of removing a natural oxide film or impurities present on the surface of the substrate by supplying a first gas containing silicon element and chlorine element to the substrate;
A second step of supplying a second gas containing a silicon element of a type different from the first gas to the substrate after the natural oxide film or the impurities are removed;
And a third step of supplying a third gas containing a different kind of silicon element from the first gas and the second gas to the substrate after the natural oxide film or the impurities have been removed. And
The first step and the second step are performed in this order with a step of purging the gas remaining on the substrate between them, and the second step and the third step are performed simultaneously, or A semiconductor device having a step of forming a silicon film on the substrate by performing the second step and the third step in this order with a step of purging gas remaining on the substrate between them. Manufacturing method. In the first step, a seed layer containing a chlorine element is formed on the surface of the substrate,
In the second step, chlorine element contained in the seed layer is replaced with silicon element contained in the second gas,
2. The method of manufacturing a semiconductor device according to claim 1, wherein in the third step, a chlorine element contained in the seed layer is replaced with a silicon element contained in the third gas.   The first gas is any one of dichlorosilane gas, trichlorosilane gas, tetrachlorosilane gas, and hexachlorodisilane gas, the second gas is any one of disilane gas and trisilane gas, and the third gas is monosilane gas. The method of manufacturing a semiconductor device according to claim 1 or 2.   The method of manufacturing a semiconductor device according to claim 1, wherein an insulating film is formed on a surface of the substrate, and the silicon film is formed on the insulating film. A first step of removing a natural oxide film or impurities present on the surface of the substrate by supplying a first gas containing silicon element and chlorine element to the substrate;
A second step of supplying a second gas containing a silicon element of a type different from the first gas to the substrate after the natural oxide film or the impurities are removed;
And a third step of supplying a third gas containing a different kind of silicon element from the first gas and the second gas to the substrate after the natural oxide film or the impurities have been removed. And
The first step and the second step are performed in this order with a step of purging the gas remaining on the substrate between them, and the second step and the third step are performed simultaneously, or A substrate processing method for forming a silicon film on the substrate by performing the second step and the third step in this order with a step of purging a gas remaining on the substrate between them. A processing chamber for processing the substrate;
A first gas supply system for supplying a first gas containing silicon element and chlorine element to the substrate in the processing chamber;
A second gas supply system for supplying a second gas containing a silicon element of a different type from the first gas to the substrate in the processing chamber;
A third gas supply system for supplying a third gas containing a silicon element of a different type from the first gas and the second gas to the substrate in the processing chamber;
In the processing chamber, by supplying the first gas to the substrate, a first process for removing a natural oxide film or impurities existing on the surface of the substrate, and the natural oxide film or impurities are removed. A second process for supplying the second gas to the substrate after the third process, and a third process for supplying the third gas to the substrate after the natural oxide film or the impurities are removed, And performing the first process and the second process in this order with a process of purging gas remaining on the substrate between them, and simultaneously performing the second process and the third process. The silicon film is formed on the substrate by performing the second process and the third process in this order with a process of purging gas remaining on the substrate between them. And the first gas supply System, a controller configured to control the second gas supply system, and the third gas supply system,
A substrate processing apparatus. A first gas supply system for supplying a first gas containing silicon element and chlorine element to the substrate;
A second gas supply system for supplying a second gas containing a silicon element of a different type from the first gas to the substrate;
A third gas supply system for supplying a third gas containing a silicon element of a different type from the first gas and the second gas to the substrate;
Supplying the first gas to the substrate from the first gas supply system to remove a natural oxide film or impurities present on the surface of the substrate; and the natural oxide film or impurities A second process for supplying the second gas from the second gas supply system to the substrate after the removal; and a third process for the substrate after the natural oxide film or the impurities are removed. And a third process for supplying the third gas from a gas supply system, and the first process and the second process are sandwiched between the processes for purging the gas remaining on the substrate in this order. And performing the second process and the third process at the same time, or interposing the process of purging the gas remaining on the substrate between the second process and the third process. On the substrate by performing in order Gas supply system which is controlled so as to form a silicon film.