KR20090051700A - Manufacturing method of semiconductor device and substrate processing apparatus - Google Patents

Abstract

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a semiconductor device and a substrate processing apparatus for uniformly forming a high quality interface between a wafer and a thin film at low oxygen / carbon density.

Carrying out and arranging a plurality of substrates in a reaction vessel comprising a process tube and a manifold supporting the same; and pre-processing gas flowing from the manifold side in the reaction vessel toward the process tube side, wherein the plurality of substrates Performing a pretreatment on the substrate; and performing a main treatment on the plurality of substrates subjected to the pretreatment by flowing the main processing gas from the manifold side in the reaction vessel toward the process tube side. And carrying out the plurality of substrates after the main processing from the reaction vessel. In the step of performing the pretreatment, a region corresponding to the manifold is provided with a pretreatment gas. At least one position in the region and a region corresponding to the substrate array region Also it is supplied from the one position of the upper.

 Process gas, process tube

Description

Manufacturing Method and Substrate Processing Apparatus for Semiconductor Device TECHNICAL FIELD

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

Specifically, in the process of manufacturing a semiconductor integrated circuit device (hereinafter referred to as IC), a wafer and a thin film are formed in a process of forming a thin film on a semiconductor wafer (hereinafter referred to as a wafer) for making an integrated circuit containing a semiconductor element. A method of forming a high quality interface therebetween and a substrate processing apparatus for realizing it.

In the manufacturing method of an IC, there exists a thing which forms a thin film on a wafer by the reduced pressure CVD method (chemical vapor deposition method).

In recent years, the following method is used to solve problems such as an increase in the native oxide film when the wafer is introduced into the reactor, deterioration of the semiconductor due to impurity deposition, and the like.

After the preliminary chamber is installed at the front end of the reactor, oxygen, water, and the like are sufficiently removed in the preliminary chamber, and the preliminary chamber is replaced with nitrogen gas, the wafer is introduced into the reactor.

In carrying out this reduced pressure CVD method, a vertical reduced pressure CVD apparatus (hereinafter referred to as a CVD apparatus with a preliminary chamber) having a preliminary chamber is used, which has a preliminary chamber formed in a sealed structure capable of vacuum evacuation at the front end of the reactor. .

In the CVD apparatus with a preliminary chamber, the wafer before the process is carried into the preliminary chamber from the wafer transport port and is set in a boat which is a jig for wafer processing. Thereafter, the preliminary chamber is hermetically closed, and oxygen, moisture, and the like are removed by repeated vacuum evacuation and nitrogen purge. The wafer is then boat loaded from the reserve chamber into the reactor by boat.

By the way, in this CVD apparatus with a preliminary chamber, contamination of the wafer surface by contaminants, such as an organic substance at the time of vacuum exhaust, is feared. This is because the drive shaft portion, the boat rotation mechanism portion, and the wiring portion for carrying the wafer and the boat into the reaction furnace are provided in the reserve chamber.

Therefore, a hydrogen (H ₂ ) annealing method is used as a method of removing a native oxide film or impurities on a wafer using a reaction gas in a reaction furnace into which a wafer is loaded. For example, it is the same as patent document 1.

<Patent Document 1> Japanese Unexamined Patent Publication No. 1993-29309

However, in this hydrogen annealing method, since high temperature treatment of 900-1000 degreeC is generally needed, the problem of thermal damage and thermal budget increase with respect to IC can be considered.

Here, in order to form a high quality interface between the wafer and the thin film at low oxygen and carbon density, it is necessary to minimize the contamination of the wafer surface from introduction of the wafer in the CVD apparatus with the pre-chamber to just before the deposition in the reactor. It is important.

Specifically, it is necessary to take the following measures for cleaning the wafer surface.

In the preliminary chamber, contamination of the wafer surface by the organic matter from the drive shaft portion, the boat rotation mechanism portion, and the wiring portion is suppressed when nitrogen is replaced before the wafer is loaded into the reactor and when it is taken out from the reactor.

In the reactor, contamination from the furnace section and the wafer itself, which are relatively low temperature, is suppressed.

High cleanliness of the furnace atmosphere and reduction and removal of the contaminants adsorbed on the surface are performed until just before the thin film is formed on the wafer.

The above-described cleaning of the wafer surface is carried out in a batch process, for example, a mass production process of 100 to 150 sheets process using a CVD apparatus with a preliminary chamber. Contamination on the wafer surface may occur unevenly in the wafer interplanar direction, that is, the wafer array direction, by the deaeration gas from the wafer or the wafer.

Disclosure of Invention An object of the present invention is to provide a semiconductor device manufacturing method and a substrate processing apparatus capable of uniformly forming a high quality interface between a wafer and a thin film at low oxygen and carbon density over a wafer interplanar direction in a batch production process. There is.

According to one aspect of the invention, a step of bringing a plurality of substrates into a reaction vessel composed of a process tube and a manifold supporting the same and arranging the plurality of substrates in the reaction vessel;

Performing pretreatment on the plurality of substrates by flowing a pretreatment gas from the manifold side in the reaction vessel toward the process tube side;

Performing a main processing on the plurality of substrates on which the pretreatment has been performed by flowing the main processing gas from the manifold side in the reaction container toward the process tube side;

And carrying out the plurality of substrates after the main treatment from the reaction vessel,

In the step of performing the pretreatment, there is provided a method for manufacturing a semiconductor device, wherein the pretreatment gas is supplied from at least one place in a region corresponding to the manifold and from at least one top in a region corresponding to a substrate array region. do.

According to still another aspect of the present invention, a step of bringing a plurality of substrates into a reaction vessel and arranging the plurality of substrates in the reaction vessel,

Performing pretreatment on the plurality of substrates by flowing a pretreatment gas into the reaction vessel;

Performing a main processing on the plurality of substrates on which the pretreatment has been performed by flowing the main processing gas into the reaction vessel;

And carrying out the plurality of substrates after the main treatment from the reaction vessel,

In the step of performing the pretreatment, a method of manufacturing a semiconductor device, wherein the pretreatment gas is supplied from at least one location in a region that is lower than the substrate array region and at least one downstream end in a region corresponding to the substrate array region. This is provided.

According to still another aspect of the present invention, a step of bringing a plurality of substrates into a reaction vessel and arranging the plurality of substrates in the reaction vessel,

Performing pretreatment on the plurality of substrates by flowing a pretreatment gas into the reaction vessel;

Performing a main processing on the plurality of substrates on which the pretreatment has been performed by flowing the main processing gas into the reaction vessel;

And carrying out the plurality of substrates after the main treatment from the reaction vessel,

In the step of performing the pretreatment, there is provided a method for manufacturing a semiconductor device, wherein the pretreatment gas is supplied from at least one place in a region below the substrate array region and from at least one upper portion in a region corresponding to the substrate array region. .

According to another aspect of the invention, the step of bringing the substrate into the reaction vessel,

Performing pretreatment on the substrate in the reaction vessel;

Performing the main processing on the substrate subjected to the pretreatment in the reaction vessel;

Carrying out the substrate after the main treatment from the reaction vessel;

In the step of performing the pretreatment, the production of a semiconductor device which supplies a pretreatment gas from a plurality of locations in the processing chamber and changes the supply flow rate, concentration, or type of the pretreatment gas at a location different from at least one of the plurality of locations. A method is provided.

According to another aspect of the invention, the step of bringing the substrate into the reaction vessel,

Performing pretreatment on the substrate in the reaction vessel;

Performing the main processing on the substrate subjected to the pretreatment in the reaction vessel;

Carrying out the substrate after the main treatment from the reaction vessel;

In the step of performing the pretreatment, a plurality of kinds of pretreatment gases are supplied from a plurality of places in the processing chamber, and at a different location from at least one of the plurality of places, a supply flow rate ratio or a concentration ratio of the plurality of kinds of pretreatment gases is different. A manufacturing method of a semiconductor device is provided.

According to still another aspect of the present invention, there is provided a process tube for processing a substrate;

A manifold supporting the process tube;

A support for arranging and supporting a plurality of substrates in the process tube;

A first nozzle for supplying gas from at least one location in a region corresponding to the manifold;

A second nozzle for supplying gas from at least one upper portion in a region corresponding to the substrate array region in the process tube;

An exhaust passage disposed on a side opposite to the side on which the first nozzle of the process tube is installed and exhausting the inside of the process tube;

The pretreatment gas is supplied from the first nozzle and the second nozzle, flows toward the exhaust passage, pretreatment is performed on the plurality of substrates, the main processing gas is supplied from at least the first nozzle, and the exhaust is exhausted. There is provided a substrate processing apparatus including a controller that flows toward a furnace and controls to perform the main processing on the plurality of substrates on which the pretreatment has been performed.

According to the present invention, in a mass production process of a batch treatment, a natural oxide film or impurities on a substrate are efficiently and uniformly removed over a substrate interplanar direction, and a high quality interface with a low oxygen and carbon density is uniform over a substrate interplanar direction. Can be formed.

EMBODIMENT OF THE INVENTION Hereinafter, one Embodiment of this invention is described based on drawing.

In this embodiment, the manufacturing method of the semiconductor device which concerns on this invention is performed using the preliminary chamber CVD apparatus (henceforth CVD apparatus) shown in FIG. 1 and FIG. 2 as a substrate processing apparatus.

In this embodiment, before forming a thin film, the gas containing a hydrogen atom, the gas containing a silicon atom, or the gas containing a chlorine atom is singly or mixed as a pretreatment gas (interfacial cleaning gas), or a carrier Together with the gas, two or more multi-gas lines are introduced into the reactor.

First, the CVD apparatus will be described.

As shown in FIG. 1, the CVD apparatus 10 includes an enclosure 11, and a preliminary chamber 12 is formed in the housing 11. The preliminary chamber 12 is built in the sealed chamber which has the airtight performance which can maintain the pressure below atmospheric pressure, and comprises the preliminary chamber provided in the front end of the reactor.

The wafer carrying in / out port 13 is opened in the front wall of the housing 11, and the wafer carrying in / out port 13 is opened and closed by the gate valve 14.

The boat loading / unloading exit 15 through which the boat 34 enters and exits is opened at the ceiling wall position of the hull 11, and the boat loading / unloading exit 15 is opened and closed by the shutter 16.

One end of an exhaust line 17 for exhausting the atmosphere in the preliminary chamber 12 is connected to the housing 11, and the other end of the exhaust line 17 is a mechanical booster as a vacuum pump via a valve 18. mechanical booster) connected to the pump 19 and the dry pump 20.

One end of a nitrogen gas supply line 21 for supplying nitrogen gas as a purge gas into the preliminary chamber 12 is connected to the housing 11, and the other end of the nitrogen gas supply line 21 is interposed through the mass flow controller 22. Is connected to the nitrogen gas supply source 23.

The boat elevator 24 for elevating the boat 34 is provided in the spare room 12 of the housing 11. The boat elevator 24 lifts and lowers the boat 34 to carry the boat 34 into or out of the processing chamber 46 described later.

The boat elevator 24 is provided with the guide rail 25 and the motor 27 which reverse-rotate the feed screw shaft 26 and the feed screw shaft 26 respectively perpendicularly installed. The lifting body 28 is freely fitted to the guide rail 25 in the vertical direction, and the lifting body 28 is screwed freely in the vertical direction to the feed screw shaft 26.

Arms 29 are horizontally protruding from the elevating body 28, and the boat loading / unloading port 15 provided on the ceiling wall of the housing 11 is hermetically closed on the upper surface of the tip of the arm 29. A seal cap 30 as a possible furnace mouth individual is provided horizontally. The seal cap 30 is abutted from the lower side in the vertical direction on the lower surface of the ceiling wall of the housing 11. The seal cap 30 is made of, for example, a metal such as stainless steel and has a disk shape. On the upper surface of the seal cap 30, an O-ring 31 serving as a seal member in contact with the lower surface of the ceiling wall of the housing 11 is placed.

The rotary mechanism 32 which rotates a boat is provided in the lower side of the seal cap 30, and the rotating shaft 33 of the rotary mechanism 32 is connected to the boat 34 through the seal cap 30. As shown in FIG. The rotating mechanism 32 rotates the wafer 1 by rotating the boat 34.

The boat 34 as the substrate holding tool is formed by using a heat resistant material such as quartz or silicon carbide, for example, and aligns the wafers 1 as a plurality of substrates in a horizontal posture while centering them. Let's see in multistage.

In the lower part of the boat 34, the heat insulation board 35 is arrange | positioned in multiple numbers in a horizontal position. The heat insulating plate 35 is made of, for example, a heat resistant material such as quartz or silicon carbide and is formed into a disk shape. The heat insulation board 35 makes it difficult to transfer the heat from the heater 42 to the preliminary chamber 12 in the state where the boat 34 was accommodated in the process chamber 46.

The drive control part 36 is electrically connected to the rotating mechanism 32 and the motor 27 of the boat elevator 24 by the electrical wiring 37. As shown in FIG. The drive control part 36 controls these at the desired timing so that the rotation mechanism 32 and the motor 27 of the boat elevator 24 can make a desired operation | movement.

The reaction furnace 40 is provided on the housing 11 corresponding to the boat loading / unloading outlet 15.

The reactor 40 includes a heater 42 as a heating mechanism. The heater 42 is formed in a cylindrical shape and is vertically provided by being supported by the heater base 41 as the holding plate. The heater 42 includes a U zone (upper zone 42a), a CU zone (center upper zone 42b), a C zone (center zone 42c), a CL zone (cneter lower zone 42d) and an L zone (lower zone 4242). It is divided into five zones of).

Inside the heater 42, a process tube 43 as a reaction tube is disposed concentrically with the heater 42. The process tube 43 is composed of an outer tube 44 as an outer reaction tube and an inner tube 45 as an inner reaction tube provided therein.

The outer tube 44 is formed using a heat resistant material such as, for example, quartz (SiO ₂ ) or silicon carbide (SiC). The outer tube 44 is formed in a cylindrical shape whose inner diameter is larger than the outer diameter of the inner tube 45 and the upper end is closed and the lower end is opened, and the outer tube 44 is provided concentrically with the inner tube 45.

The inner tube 45 is formed into a cylindrical shape in which a heat resistant material such as quartz or silicon carbide is used, and the upper and lower ends thereof are opened. The tubular hollow portion of the inner tube 45 forms the processing chamber 46, and the processing chamber 46 accommodates the plurality of wafers 1 in a state in which the boat 34 is arranged in multiple stages in the vertical direction from the horizontal posture. .

The cylindrical space 47 is formed by the gap between the outer tube 44 and the inner tube 45.

Under the outer tube 44, the manifold 49 is arrange | positioned concentrically with the outer tube 44 via the O-ring 48 as a sealing member. Stainless steel is used for the manifold 49, for example, and is formed in the cylindrical shape which opened the upper end and the lower end.

The manifold 49 engages with the outer tube 44 and the inner tube 45 and supports them. The manifold 49 is supported by the heater base 41 and the ceiling wall of the housing 11, whereby the process tube 43 is in a vertically installed state.

The reaction vessel is formed by the process tube 43 and the manifold 49.

In the process tube 43, a temperature sensor 50 as a temperature detector is provided. The temperature control part 51 is electrically connected to the heater 42 and the temperature sensor 50 by the electrical wiring 52. The temperature control part 51 adjusts the energization state with respect to the heater 42 based on the temperature information detected by the temperature sensor 50, and controls it by desired timing so that the temperature in the process chamber 46 may have a desired temperature distribution.

The manifold 49 is provided with an exhaust pipe 53 for exhausting the atmosphere in the processing chamber 46. The exhaust pipe 53 is disposed at the lower end of the tubular space 47 formed by the gap between the outer tube 44 and the inner tube 45 and communicates with the tubular space 47. .

On the downstream side of the exhaust pipe 53 opposite to the connection side with the manifold 49, a mechanical booster pump (MBP, 19) and a dry pump via a pressure sensor 54 and a pressure regulator 55 as a pressure detector. Exhaust devices such as DP and 20 are connected. The pressure sensor 54, the pressure regulating device 55, the mechanical booster pump 19, and the dry pump 20 exhaust the pressure in the processing chamber 46 to be a predetermined pressure (vacuum degree).

The pressure control part 56 is electrically connected to the pressure sensor 54 and the pressure regulator 55 by the electrical wiring 57. The pressure controller 56 controls the pressure adjusting device 55 at a desired timing so that the pressure in the processing chamber 46 becomes a desired pressure based on the pressure detected by the pressure sensor 54.

A plurality of nozzles as gas introduction portions are connected to the manifold 49 so as to communicate in the processing chamber 46.

The plurality of nozzles are composed of four long nozzles of elbow tube shape (L type) different in length from each other, and one short nozzle of straight pipe shape (I type).

The 1st long nozzle N1, the 2nd long nozzle N2, the 3rd long nozzle N3, and the 4th long nozzle N4 are provided between the boat 34 and the inner tube 45, and a wafer group (Iii) It protrudes to the area | region which opposes the heater 42 which is an array area | region.

The gas ejection openings of the first long nozzle N1, the second long nozzle N2, the third long nozzle N3, and the fourth long nozzle N4 are respectively at different heights in regions corresponding to the wafer group array region. Both of them are located upward in the wafer group array direction (vertical direction).

The gas ejection opening of the short nozzle N5 which is the fifth nozzle is a region facing the manifold 49 which is an upstream region of the wafer group array region, that is, a region lower than the wafer group array region and lower than the wafer group array region. It is located in the area | region which becomes this, and it opens toward a direction orthogonal to a wafer group arrangement direction (horizontal direction).

In FIG. 2, only the 1st long nozzle N1 which is a 1st nozzle is shown for convenience, and illustration of another nozzle is abbreviate | omitted.

Gas supply lines L1 to L5 are connected to these nozzles N1 to N5, respectively. A gas supply / flow controller including a plurality of valves and a plurality of gas flow controllers on an upstream side of the gas supply lines L1 to L5 opposite to the connection side with the nozzles N1 to N5. A gas supply unit G including a plurality of gas supply sources is connected via M).

The gas supply / flow rate control unit 58 is electrically connected to the gas supply / flow rate controller M by the electric wiring 59. The gas supply / flow rate control unit 58 controls the gas supply / flow rate controller M at a desired timing so that the gas flow rate of each gas flowing through each gas supply line L1 to L5 becomes a desired amount.

10 (a) and 10 (b) show specific examples of the gas supply system. FIG. 10A shows an example (hereinafter referred to as an example of a first supply system) used when performing a first preprocessing sequence described later.

In the example of the first feed system, a first gas supply source (G1) it is supplied to the hydrogen (H ₂₎ gas to each gas supply line (L1 ~ L5). The second gas source G2 supplies a monosilane (SiH ₄ ) gas to the gas supply line L5. The third gas supply source G3 supplies nitrogen (N ₂ ) gas to each gas supply line L1 to L5.

In each of the gas supply lines L1 to L5 for supplying hydrogen gas from the first gas supply source G1, the upstream valves U1 to U5, the mass flow controllers C1 to C5, and the downstream valves sequentially from the upstream side. D1 to D5 are provided respectively.

From the second gas supply source G2 to the connection line for supplying the monosilane gas to the gas supply line L5, the upstream valve U6, the mass flow controller C6, and the downstream valve D6 are sequentially sequentially from the upstream side. ) Is installed.

From the 3rd gas supply source G3 to the connection line which supplies nitrogen gas to each gas supply line L1-L5, the upstream valve U7, the mass flow controller C7, and the downstream valve sequentially from an upstream side. (D7) is installed. On the other hand, the gas supply unit G includes the first gas supply source G1, the second gas supply source G2, and the third gas supply source G3, and the gas supply / flow controller M includes an upstream valve. (U1-U7), mass flow controllers C1-C7, and downstream valves D1-D7.

That is, in the example of the first supply system, when hydrogen gas is used as the pretreatment gas, the flow rate and concentration of the hydrogen gas are controlled by controlling the respective valves and the mass flow controllers of the gas supply / flow controller M. It can change for every supply line L1-L5, ie, every nozzle N1-N5, respectively.

FIG. 10 (b) shows an example (hereinafter referred to as an example of a second supply system) used when performing the second preprocessing sequence described later.

In the example of a 2nd supply system, the 1st gas supply source G1 supplies hydrogen gas to each gas supply line L1-L5. The second gas supply source G2 supplies the monosilane gas to each gas supply line L1 to L5. The fourth gas supply source G4 supplies chlorine (Cl ₂ ) gas to each gas supply line L1 to N5. The third gas supply source G3 supplies nitrogen gas to each gas supply line L1 to L5.

In each of the gas supply lines L1 to L5 for supplying hydrogen gas from the first gas supply source G1, the upstream valves U1 to U5, the mass flow controllers C1 to C5, and the downstream valves sequentially from the upstream side. D1 to D5 are provided respectively.

Upstream valves U11 to U15 and mass flow controllers C11 to C15 are sequentially connected from the upstream side to each connection line for supplying monosilane gas from the second gas supply source G2 to the respective gas supply lines L1 to L5. ) And downstream valves D11 to D15 are provided, respectively.

Each connecting line for supplying chlorine gas to each gas supply line L1 to L5 from the fourth gas supply source G4 is sequentially provided with an upstream valve U16 to U20 and a mass flow controller C16 to C20 from the upstream side. ) And downstream valves D16 to D20 are respectively provided.

Upstream valves U21 to U25 and mass flow controllers C21 to C25 are sequentially supplied from the upstream side to each connection line for supplying nitrogen gas to the respective gas supply lines L1 to L5 from the third gas supply source G3. And downstream valves D21 to D25 are respectively provided. On the other hand, the gas supply unit G includes a first gas supply source G1, a second gas supply source G2, a third gas supply source G3, and a fourth gas supply source G4, and includes a gas supply and flow rate controller. (M) includes upstream valves U1 to U5 and U11 to U25, mass flow controllers C1 to C5 and C11 to C25, and downstream valves D1 to D5 and D11 to D25.

That is, the example of the 2nd supply system controls each valve | bulb and each mass flow controller of the gas supply / flow controller M, so that the flow volume and concentration of hydrogen gas, monosilane gas, and chlorine gas can be adjusted for each gas supply line L1. It is possible to change each of ˜L5, that is, each nozzle N1 to N5.

The drive control part 36, the temperature control part 51, the pressure control part 56, and the gas flow control part 58 comprise an operation part and an input / output part, and these are electrically connected to the main control part 60 which controls the CVD apparatus 10 whole. Connected.

These drive control part 36, the temperature control part 51, the pressure control part 56, the gas flow control part 58, and the main control part 60 comprise the controller 61. As shown in FIG.

Next, as one step of the semiconductor device manufacturing process according to one embodiment of the present invention, a polycrystalline silicon film or single crystal silicon is formed on a wafer using the CVD apparatus 10 according to the above configuration. A method of forming a film (hereinafter referred to as a silicon film) will be described based on FIGS. 3 and 4.

3 and 4 are sequence flow charts showing a method of forming a silicon film on a wafer, wherein the furnace temperature change, each step name, nitrogen (N ₂ ) gas, hydrogen (H ₂ ) gas, silane (SiH ₄ ) gas, Each supply timing of the chlorine (Cl ₂ ) gas and the like and the pressure change in the furnace are respectively shown.

In FIG.3 and FIG.4, the horizontal axis has shown time progress, and the vertical axis | shaft has shown the furnace temperature, each step, the supply state of each gas, and the furnace pressure.

3 shows a silicon film forming method according to the first embodiment, and FIG. 4 shows a silicon film forming method according to the second embodiment.

In addition, in the following description, operation | movement of each part which comprises the CVD apparatus 10 is controlled by the controller 61. As shown in FIG.

After removing the native oxide film on the surface of the silicon wafer with dilute hydrofluoric acid (dihydrofluoric acid) and subjecting the surface to hydrogen termination, the number of batches of one batch is provided in the boat 34 in the preliminary chamber 12. For example, 100 to 150 wafers 1 are loaded (wafer charge step).

Subsequently, purge with an inert gas in the preliminary chamber 12, for example, a nitrogen purge is performed (pre-purge step), and vacuum evacuation and nitrogen purge are repeatedly performed in the preliminary chamber 12 (cycle purge step). . As a result, oxygen and moisture in the atmosphere in the preliminary chamber 12 are sufficiently removed.

Thereafter, the boat elevator 24 raises the boat 34 on which the wafer group loading is completed, and loads the boat 34 into the processing chamber 46 through the boat loading / unloading port 15.

When the loading of the boat 34 supporting the plurality of wafers 1 into the processing chamber 46 is completed, the seal cap 30 has a lower surface of the ceiling wall of the housing 11 constituting the boat loading / unloading port 15. The inside of the processing chamber 46 is sealed by abutting through the O-ring 31 and closing the boat loading / unloading outlet 15.

At this time, in order to prevent wafer surface oxidation during the boat load step, the wafer loading temperature, for example, the temperature in the reactor 40 (the processing chamber 46) (hereinafter referred to as the furnace) is lower than the wafer processing temperature, for example, The temperature control part 51 controls the heater 42 so that it may become a temperature of about 100-400 degreeC.

In the case of FIG. 3 and FIG. 4, wafer loading temperature is adjusted to 200 degreeC.

On the other hand, the pressure in the furnace becomes atmospheric pressure (ATM) from the wafer charge step to the boat load step.

Next, the furnace is evacuated by the mechanical booster pump 19 and the dry pump 20 while maintaining the furnace temperature at the wafer loading temperature (vacuum evacuation step).

At this time, the pressure control unit 56 controls the pressure adjusting device 55 so that the pressure in the furnace is adjusted to a pressure lower than the atmospheric pressure and lower than the pressure during the wafer processing, for example, about 1 to 10000 Pa.

In the case of FIGS. 3 and 4, the pressure in the furnace is adjusted to 1 Pa.

At this time, the drive control part 36 rotates the boat 34 by the rotation mechanism 32 at a predetermined rotational speed.

The above steps are the initial steps common to the sequence of the silicon film forming method according to the first and second embodiments shown in FIGS. 3 and 4.

Next, in the first embodiment shown in FIG. 3, a hydrogen gas use decontamination sequence (hereinafter referred to as a first pretreatment sequence) will be described.

After the furnace pressure is adjusted to a predetermined pressure (45 Pa in this case), while the hydrogen gas is supplied into the furnace while the furnace is exhausted, the furnace is purged with hydrogen gas (hydrogen purge step).

Thereafter, in the state where the supply and exhaust of hydrogen gas to the furnace are maintained, the furnace temperature is raised from the wafer loading temperature to the temperature of the first pretreatment temperature, for example, about 750 to 850 ° C (heating step).

Before this temperature increase step, that is, from the hydrogen purge step, supply of hydrogen gas into the furnace is started.

The supply and exhaust of hydrogen gas to the furnace stabilizes the temperature reduction step and the furnace temperature at the film formation temperature, which lower the furnace temperature from the first pretreatment temperature (750 to 850 ° C.) to the film formation temperature (620 ° C.) described later. This is done continuously until the temperature stabilization step is complete.

Hydrogen gas is supplied into a furnace from all the nozzles N1-N5 shown in FIG. That is, the shot nozzle N5 located in the region corresponding to the manifold 49 and the gas ejection opening are supplied from the long nozzles N1 to N4 located in the region corresponding to the wafer group array region. The hydrogen gas supplied into the furnace rises in the furnace, flows down the cylindrical space 47, and is exhausted from the exhaust pipe 53.

By supplying and exhausting hydrogen gas for a predetermined time, the removal process of the native oxide film and contaminants on the wafer is continued for a predetermined time. The reaction mechanism in the removal process of the natural oxide film and the contaminants, that is, the removal mechanism by hydrogen of oxygen (O), carbon (C), and natural oxide film (SiO ₂ ) will be described below.

By supplying hydrogen gas into the furnace, it can be considered that the following reaction proceeds.

In addition, in the following formula, the thing which added * shows that it is an active species.

H ₂ → 2H ^*

2H ^* + O → H ₂ O ↑

2H ₂ + C → CH ₄ ↑

SiO ₂ + 2H ^* → SiO ↑ + H ₂ O ↑

In the temperature range of 750 ° C. to 850 ° C., H ₂ can be considered to be separated into chemically active H ^* or the like (Scheme 1).

These may be considered to react with oxygen, carbon, and natural oxide film remaining in the furnace atmosphere, vaporize in the form of H ₂ O, CH ₄ , SiO, etc., and remove them by exhausting them to the outside of the furnace (Scheme 2, 3, 4). ).

Next, a decontamination sequence (hereinafter referred to as a second pretreatment sequence) using hydrogen gas, silane gas, and chlorine gas in the second embodiment shown in FIG. 4 will be described.

After the furnace pressure is adjusted to a predetermined pressure (45 Pa in this case), while the hydrogen gas is supplied into the furnace while the furnace is exhausted, the furnace is purged with hydrogen gas (hydrogen purge step).

Thereafter, in the state where the supply and exhaust of hydrogen gas to the furnace are maintained, the furnace temperature is raised from the wafer loading temperature to a second pretreatment temperature, for example, a temperature of about 620 ° C (heating step).

In addition, in 2nd Embodiment, 2nd preprocessing temperature and film-forming temperature mentioned later are made into the same temperature.

From this temperature increase step, supply of silane gas and chlorine gas to an furnace is started.

That is, at this time, the hydrogen gas, the silane gas, and the chlorine gas are supplied into the furnace to exhaust the inside of the furnace (hydrogen + silane + chlorine purge step).

The in-house pressure at this time is adjusted to 50 Pa, for example.

On the other hand, the silane gas and the chlorine gas continue to be supplied for a predetermined time even after the temperature increase step ends.

When the supply of the silane gas and the chlorine gas is stopped while the hydrogen gas supply is maintained, the hydrogen purge step is performed again. That is, the supply and the exhaust of the hydrogen gas are continued until the hydrogen purge step after the temperature increase step is completed from the hydrogen purge step before the temperature increase step.

By executing the hydrogen purge step after the silane gas and the chlorine gas supply stop, it is possible to remove chlorine remaining on the wafer surface.

Hydrogen gas, silane gas, and chlorine gas are supplied into the furnace from all the nozzles N1 to N5 shown in FIG. 1. That is, from the short nozzle N5 in which the gas jet port is located in the area | region corresponding to the manifold 49, and from the long nozzles N1-N4 in which the gas jet port is located in the area | region corresponding to a wafer group arrangement area | region, it transfers to a hydrogen purge step. In each case, hydrogen gas is supplied, and in the hydrogen + silane + chlorine purge step, hydrogen gas, a mixed gas of silane gas, and chlorine gas is supplied, respectively. Hydrogen gas, silane gas, and chlorine gas supplied into the furnace ascend in the furnace, flow down the cylindrical space 47, and are exhausted from the exhaust pipe 53.

The supply and exhaust of the hydrogen gas, the silane gas, and the chlorine gas are maintained for a predetermined time, so that the natural oxide film and contaminant removal processing for the wafer is continued for a predetermined time. The reaction mechanism in the removal process of the native oxide film and contaminants is described below.

First, the mechanism of removing water (H ₂ O) and oxygen (O) by silane will be described.

It is considered that the following reaction proceeds by supplying the silane gas into the furnace.

SiH ₄ → SiH ₂ + H ₂

SiH ₄ → SiH ₃ + H ^*

SiH ₂ + H ₂ O ↑ → SiO ↑ + 2H ₂

2SiH ₂ + O ₂ → 2SiO ↑ + 2H ₂

2H ^* + O → H ₂ O ↑

SiH ₄ + SiO ₂ → 2SiO ↑ + 2H ₂

In a relatively low temperature range within the range of 200 to 620 ° C., silane (SiH ₄ ) is not completely decomposed and can be considered to be separated in the form of SiH ₂ and H ₂ or SiH ₃ and H (Scheme 5, 6). ).

It can be considered that they react with moisture and oxygen remaining in the atmosphere in the furnace, vaporize in the form of SiO, H ₂ O, etc., respectively, and are removed by evacuation to the outside of the furnace (Scheme 7, 8, 9).

However, since it is relatively low temperature, it does not reach until removing SiO ₂ formed on the wafer surface as in Scheme 10.

Next, the mechanism for removing oxygen (O) and carbon (C) by chlorine will be described.

When chlorine gas is supplied into a furnace, it can be considered that the following reaction proceeds.

2Cl ₂ + Si → SiCl ₄ ↑

It can be considered that there is no direct reaction with O or C by Cl ₂ , but it can be considered that Si is etched by Cl ₂ (Scheme 11).

At that time, it is considered that O and C adsorbed on Si are lifted up and removed together with Si.

Each of the first pretreatment sequence and the second pretreatment sequence alone is effective for removing the native oxide film and the contaminant on the wafer, but it is also possible to combine both.

By combining both, it is possible to obtain a higher natural oxide film or an effect of removing impurities.

After the end of the first preprocessing sequence or the second preprocessing sequence, the film forming step is executed.

Hereafter, the steps common to the silicon film forming method sequences shown in FIGS. 3 and 4 are described.

When the heater 42 is controlled by the temperature control unit 51 and the furnace temperature is stabilized at the film formation temperature (620 ° C) (temperature stabilization step), the hydrogen gas supply is stopped in the furnace, and the silane gas is supplied into the furnace. At this time, the furnace pressure is adjusted to 20 Pa, for example. Silane gas is supplied into the furnace from the shot nozzle N5. In addition, silane gas may be supplied to the furnace from all the nozzles N1-N5. The silane gas supplied into the furnace rises in the furnace, flows down the cylindrical space 47, and is exhausted from the exhaust pipe 53.

Since the supplied silane gas decomposes in the reduced pressure atmosphere heated by the heater 42, a silicon film is formed on the wafer surface by thermal CVD reaction (film formation step).

When the surface of the wafer is cleaned by the first pretreatment sequence or the second pretreatment sequence, a polycrystalline silicon film is formed when the underlying film is polycrystalline silicon (poly-Si), and when the underlying film is monocrystalline silicon, A silicon film is formed.

Thus, according to this embodiment, a single crystal silicon film can be formed at low temperature of 620 degreeC.

By stopping the supply of the silane gas, the film forming step for the wafer is completed.

After completion of the film forming step for the wafer, the pressure in the furnace is adjusted to a predetermined pressure, for example, a pressure of about 1 to 10,000 Pa. Here, the furnace pressure is adjusted to 15 Pa.

Simultaneously with the silane gas supply stop, the furnace is purged with nitrogen gas, whereby the furnace is replaced with nitrogen gas.

Thereafter, while the nitrogen gas supply is maintained in the furnace, the pressure in the furnace is raised to return to atmospheric pressure (atmospheric pressure return step).

After the atmospheric pressure return step, the boat 34 holding the processed wafer, i.e., the wafer on which the single crystal silicon film or the polycrystalline silicon film is formed, is dropped by the boat elevator 24 and taken out from the process chamber 46 (boat unload step).

The boat 34 waits in the preliminary chamber 12 until all the wafers 1 held by the boat 34 are cooled (wafer cooling step).

When all the wafers 1 held by the boat 34 which have been waited to cool to a predetermined temperature, the wafer 1 is taken out from the boat 34 by a wafer transfer device (not shown), and the wafer carrier Wafer discharge step (not shown).

On the other hand, for the next sequence, the furnace temperature is lowered from the film formation temperature to a predetermined wafer loading temperature, for example, about 300 to 600 ° C. (here, 200 ° C.) in parallel with the wafer cooling step (inner temperature reduction). step).

As a result of examining the silicon film forming method, the present inventors found the following phenomenon.

Like the CVD apparatus 10 in this embodiment, a reaction vessel is formed of the process tube 43 and the manifold 49 provided below the process tube 43, and from the manifold 49 side, In the case of the substrate processing apparatus in which gas flows toward the upper portion of the process tube 43, the portion of the manifold 49 which is lower than the wafer group array region and lower than the wafer group array region and the upper portion of the wafer group array region (wafer group array). In the vicinity of the region downstream end portion, the degree of contamination of oxygen, carbon, or the like becomes larger than that of other portions.

This inventor considered the reason why this phenomenon arises as follows.

In the film forming step, the gas introduced from the shot nozzle N5 near the manifold 49 having a relatively lower temperature than the wafer group array region is raised in the processing chamber 46 to form a film with respect to the wafer 1. After the operation, the exhaust pipe 53 is exhausted from the tubular space 47 formed between the outer tube 44 and the inner tube 45.

When the inside of the furnace is divided into three areas (area) near the upper portion of the wafer group array region, the portion other than the upper portion of the wafer group array region, and the manifold 49, the interfacial impurity density of the wafer, such as oxygen or carbon, It becomes relatively large in the upper part of the wafer group arrangement region and in the vicinity of the manifold 49.

As a reason for the relatively high interfacial impurity density in the vicinity of the manifold 49, contamination due to desorption of moisture and organic matter adhering to the manifold 49 can be considered.

Since moisture and organic substances that cause interfacial impurities are more easily adsorbed on the surface as the ambient temperature is lower, more moisture and organic substances are adsorbed in the vicinity of the manifold 49 where the temperature is relatively lower in the furnace, It is conceivable that they desorb at the time of the temperature increase in the film formation sequence, and adsorb | suck to the wafer 1 of the manifold 49 vicinity.

As the reason for the relatively high interfacial impurity density in the upper portion of the wafer group array region, contamination due to desorption of moisture and organic matter adhering to the wafer 1 or the boat 34 can be considered.

Since the desorbed moisture and organic substances flow from the bottom to the wafer group array region in the structure of the reactor 40, it is assumed that the wafers 1 are evenly arranged in the wafer group array region. It is conceivable that the upper portion of the wafer group array region is affected by desorption water and organic matter from more portions than the surfaces of more wafers 1 and boats 34.

In addition, due to the structure of the reactor 40, the influence of dediffusion of impurities from the exhaust side can be considered to be stronger even in the upper portion of the wafer group array region located near the cylindrical space 47.

The inventors thus increase the degree of contamination than other parts,

(1) an area below the wafer group array region (upstream of the wafer group array region), that is, a region corresponding to a manifold that is lower than the wafer group array region;

(2) an area corresponding to the upper portion of the wafer group array region (the downstream end of the wafer group array region)

It has been found that this phenomenon can be improved by actively supplying the pretreatment gas from the present invention.

Next, an experiment performed to identify the difference by the supply gas system number of the natural oxide film / pollutant removal effect (hereinafter, referred to as a decontamination effect) on the wafer will be described.

5 shows the evaluation apparatus used for the experiment.

In addition, about the component same as FIG. 1, the same code | symbol is attached | subjected and the description is abbreviate | omitted.

In the first evaluation device shown in FIG. 5A, after the hydrogen gas is introduced into the furnace with only one system of the shot nozzles N5 and the first pretreatment sequence is performed on the wafer 1, the shot nozzles N5. The silane gas was introduced into the furnace from the film forming step.

The interfacial oxygen-carbon density, which is an index of the decontamination effect, was measured for the monitor wafers provided in the center region (89th) and the upper region (167th) of the boat 34.

In the second evaluation apparatus shown in FIG. 5B, hydrogen gas is introduced into the furnace by two systems of the short nozzle N5 and one long nozzle N1, and the first pretreatment sequence for the wafer 1. After the process, the silane gas was introduced into the furnace from the shot nozzle N5 and the film forming step was performed. That is, in the first pretreatment sequence, not only hydrogen is supplied from the manifold 49 by the short nozzle N5, but also the upper portion of the boat having a relatively high influence of contamination by degassing from the boat 34 or the wafer 1. In order to improve the interface characteristics of the region 167th, hydrogen gas was further introduced by the long nozzle N1 even slightly below (150th). Similarly to the experiment by the first evaluation device, a monitor wafer was placed in the center region (89th) and the upper region (167th) of the boat 34 to measure the interfacial oxygen and carbon density.

6 is a graph showing experimental results.

In FIG. 6, the horizontal axis | shaft has shown the difference of the evaluation apparatus, ie, supply gas system number, and the vertical axis | shaft has shown interfacial oxygen-carbon density (atoms / cm <^2> ).

In this experiment, the hydrogen gas purge temperature of the 1st pretreatment sequence was 800 degreeC, the hydrogen gas purge time was 30 minutes, and the supply flow volume of the hydrogen gas supplied from each nozzle was 5 slm, respectively.

In the film forming step, the supply flow rate of the silane gas was set to 0.5 slm, and about 200 nm of the polycrystalline silicon film was formed on the about 100 nm thick polycrystalline silicon film which is an underlayer.

Interfacial properties were measured with a Secondary Ionization Mass Spectrometer (SIMS).

According to FIG. 6, it turns out that the influence of the contamination by the degassing from a boat and a wafer is comparatively high in a boat upper area | region in the 1st evaluation apparatus with the number of hydrogen gas system | system | groups.

When comparing the interface characteristics in the monitor wafer provided in the boat center area | region (89th), a difference is hardly seen in a 1st evaluation apparatus and a 2nd evaluation apparatus.

From this, it can be seen that there is almost no error between the increase in the flow rate of the hydrogen gas when the number of hydrogen gas systems is changed from one system to the two systems, the influence of the pressure increase in the hydrogen gas purge, and the evaluation batch.

On the other hand, comparing the interface characteristics of the monitor wafer provided in the upper region (167th) with the first and second evaluation apparatuses, the number of hydrogen gas systems is increased from one system to two systems and the upper region 167 Second), by additionally supplying hydrogen gas from a slightly ahead (upstream side) of the upper region (167th), it is possible to reduce about 61% in oxygen density and about 44% in carbon density, and the pollution density is large. It can be seen that it is reduced.

From this, by further supplying pretreatment gas such as hydrogen gas into multiple systems, contaminants on the surface of the wafer that enter unevenly in the wafer interplanar direction are uniformly removed, and a wafer group of mass production processing having a high quality interface is produced. It can form uniformly in the arrangement area | region (100-150 sheets).

In the case of FIG.5 (b), the gas kind, supply flow volume, and density | concentration of the pretreatment gas as interface cleaning gas supplied to long nozzle N1 and shot nozzle N5 were made the same.

That is, the gas types of the pretreatment gas supplied to the long nozzle N1 and the short nozzle N5 were all hydrogen gas. In addition, the hydrogen gas flow rates supplied to the long nozzle N1 and the short nozzle N5 were all 5 slm. In addition, the density | concentration of the hydrogen gas supplied to long nozzle N1 and shot nozzle N5 was 100% in all.

However, for example, when the degree of contamination in the processing chamber is nonuniform in the interplanar direction, the gas type, supply flow rate and concentration of the pretreatment gas as the interfacial cleaning gas supplied to each nozzle are different depending on the amount of contamination in the processing chamber as follows. You may also

(1) For example, when the degree of contamination at the upper part in the processing chamber is larger than other parts, the pretreatment for supplying the supply flow rate or concentration of the pretreatment gas supplied from the long nozzle N1 to the upper part in the processing chamber to another part. You may make it larger than the supply flow volume or concentration of gas.

The gas type of the pretreatment gas supplied from the long nozzle N1 to the upper part of the processing chamber may be different from the gas kind of the pretreatment gas supplied to the other part.

For example, in the case of the apparatus of FIG. 5 (b), the supply flow rate of the hydrogen gas supplied from the long nozzle N1 to the upper part of the processing chamber, and the supply flow rate of the hydrogen gas supplied from the short nozzle N5 to the lower part of the processing chamber, The concentration of hydrogen gas supplied from the long nozzle N1 to the upper part of the process chamber and the concentration of the hydrogen gas supplied from the short nozzle N5 to the lower part of the process chamber may be 100% and 80%, respectively. You may also

Further, even if the pretreatment gas supplied from the long nozzle N1 to the upper portion of the processing chamber is a mixed gas of hydrogen gas, silane gas, and chlorine gas, the pretreatment gas supplied from the short nozzle N5 to the lower portion of the processing chamber is hydrogen gas. do.

(2) Further, for example, when the degree of contamination in the upper and lower portions of the processing chamber is larger than other portions, the pretreatment for supplying the supply flow rate or concentration of the pretreatment gas supplied to the upper and lower portions in the processing chamber to other portions. You may make it larger than the supply flow volume or concentration of gas.

In addition, the gas kind of the pretreatment gas supplied to the upper part and the lower part in a process chamber may be different from the gas kind of the pretreatment gas supplied to another part.

For example, in the above-described CVD apparatus 10 of FIGS. 1 and 2, the supply flow rate of hydrogen gas supplied from the longest long nozzle N1 to the upper part of the processing chamber, and the second longest nozzle N ₂ . Flow rate of hydrogen gas supplied from the third upper (second shortest) long nozzle N3 to the center upper part in the processing chamber from the gas chamber, supply flow rate of hydrogen gas supplied from the third longest (second short) long nozzle N3, the shortest long nozzle N4 The supply flow rate of the hydrogen gas supplied to the process chamber bottom from the bottom and the supply flow rate of the hydrogen gas supplied to the process chamber lower part from the short nozzle N5 may be 8 slm, 6 slm, 5 slm, 6 slm, and 7 slm, respectively.

In addition, the concentration of hydrogen gas supplied from the longest long nozzle N1 to the upper part of the process chamber, the concentration of hydrogen gas supplied from the second longest long nozzle N ₂ to the center upper part of the process chamber, and the third longest (two Concentration of hydrogen gas supplied from the shortest long nozzle N3 to the center lower portion of the processing chamber, concentration of hydrogen gas supplied from the shortest long nozzle N4 to the processing chamber bottom, and supplied from the short nozzle N5 to the lower processing chamber. The concentration of hydrogen gas may be 100%, 80%, 80%, 90%, 100%, respectively.

In addition, the pretreatment gas supplied from the longest long nozzle N1 to the upper part of a process chamber is made into the mixed gas of hydrogen gas, silane gas, and chlorine gas, and is supplied to the center upper part of a process chamber from the second longest nozzle N2. The pretreatment gas, the pretreatment gas supplied from the third longest (second shortest) long nozzle N3 to the center lower part in the process chamber, the pretreatment gas supplied from the shortest long nozzle N4 to the process chamber bottom, is hydrogen gas, The pretreatment gas supplied from the shot nozzle N5 to the lower portion of the processing chamber may be a mixed gas of hydrogen gas, silane gas, and chlorine gas.

That is, in the step of performing the pretreatment, the pretreatment gas may be supplied from a plurality of locations in the processing chamber, and at a different location from at least one of the plurality of locations, the supply flow rate, concentration, or type of the pretreatment gas may be different.

Thus, by varying the supply flow rate, concentration, or type of pretreatment gas at each position in accordance with the degree of contamination at each position in the processing chamber, the natural oxide film or impurities on the wafer can be efficiently and uniformly spread across the wafer plane. It can be removed, and it can form uniformly in the mass production process which batch-processes 100-150 sheets of a high quality interface at low oxygen and carbon density.

(3) Also, for example, when the degree of contamination in the upper and lower parts of the processing chamber is larger than in other parts, the pretreatment gas supplied from the upper and lower parts of the processing chamber is a mixed gas in which a plurality of kinds of pretreatment gases are mixed. In the case where the pretreatment gas supplied from another part in the processing chamber is the same as the mixed gas, the plural kinds of supply flow rate ratios or concentration ratios of the plural types of pretreatment gas supplied from the upper and lower parts in the processing chamber are supplied from other parts. May be different from the supply flow rate ratio or the concentration ratio of the pretreatment gas.

For example, in the above-described CVD apparatus 10, when supplying a mixed gas of hydrogen gas, silane gas and chlorine gas as pretreatment gas from each nozzle, hydrogen supplied from the long nozzle N1 to the upper part of the process chamber. Supply flow rate ratio of gas, silane gas, and chlorine gas, supply flow rate ratio of hydrogen gas, silane gas, and chlorine gas supplied from the long nozzles (N2, N3, N4) to the upper, middle, and bottom portions of the processing chamber, and the short nozzle (N5) The supply flow rate ratios of the hydrogen gas, the silane gas, and the chlorine gas supplied from the lower portion of the processing chamber may be set to 5: 3: 2, 8: 1: 1, 6: 3: 1, respectively.

That is, in the step of performing the pretreatment, a plurality of types of pretreatment gases may be supplied from a plurality of places in the processing chamber, and at a different location from at least one of the plurality of places, the supply flow rate ratio or the concentration ratio of the plurality of types of pretreatment gases may be different.

Thus, by varying the supply flow rate or concentration ratio of the plural kinds of pretreatment gases in each position in accordance with the degree of contamination at each position in the processing chamber, the natural oxide film or impurities on the wafer can be removed efficiently and uniformly across the wafer interplanar direction. Therefore, it can form uniformly in the mass-production process which batch-processes 100-150 sheets of high quality interface at low oxygen and carbon density.

As multiple places in the process chamber which supply a pretreatment gas, it is preferable to set it as at least 1 place in an upstream region rather than a wafer group arrangement area | region, and at least 1 place in the area | region corresponding to a wafer group arrangement area | region.

More preferably, the pretreatment gas is supplied from at least one place in the region corresponding to the manifold and from at least one place in the upper portion in the region corresponding to the wafer group arrangement region.

That is, it is more preferable to supply the pretreatment gas from at least one place at a downstream end in at least one place and a region corresponding to the wafer group arrangement area in a region that is lower than the wafer group arrangement area,

It is more preferable to supply from at least one place in the lower region than the wafer group array region and from at least one upper portion in the region corresponding to the wafer group array region.

Moreover, it is preferable that the preprocessing gas nozzle which supplies a pretreatment gas, and this process gas nozzle which supplies the film-forming gas as this process gas are the same nozzle.

Next, when the degree of contamination in the lower part of the process chamber is large, the interface contamination (interface oxygen density) when the flow rate ratio of chlorine gas and hydrogen gas supplied as a pretreatment gas from the short nozzle N5 to the lower part of the process chamber is changed. The experiments performed to identify the differences between are described.

Experiment was performed using the 1st evaluation apparatus of FIG.

That is, after the pretreatment of the wafer was performed by introducing a mixed gas of chlorine gas and hydrogen gas as the pretreatment gas into the furnace using the first evaluation device of FIG. 5 (a), a D-polySi film was applied to the wafer at 100 nm. Formed.

At the time of pretreatment, the flow rate ratio of chlorine gas and hydrogen gas was changed into two types: chlorine / hydrogen = 0.02 and chlorine / hydrogen = 0.1.

The measurement of the interface pollutant (interface oxygen density) was performed by providing a monitor wafer in the lower region (11th) of the boat.

The difference by the flow ratio of chlorine gas and hydrogen gas of interfacial oxygen density is shown in FIG.

In FIG. 7, the horizontal axis represents the flow rate ratio (chlorine / hydrogen) of chlorine gas and hydrogen gas, and the vertical axis represents the interface oxygen density (atoms / cm ² ).

Interface characteristics were measured by SIMS.

According to Fig. 7, the following facts can be seen.

At the time of pretreatment, when the flow rate ratio of chlorine gas and hydrogen gas is chlorine / hydrogen = 0.1, the interface oxygen density is lower than when chlorine / hydrogen = 0.02.

In other words, an increase in the ratio of chlorine gas to hydrogen gas (chlorine / hydrogen) yields a high quality interface at low oxygen. This is considered to be because the etching of the wafer is accelerated and the decontamination effect is increased by increasing the ratio of chlorine gas.

As discussed for the description of the second pretreatment sequence, when chlorine gas is used, the interfacial impurities can be removed by etching the silicon wafer using the reaction of Cl ₂ and Si as shown in Scheme 11.

In this case, in order to make the film thickness distribution in the wafer interplanar direction after pretreatment uniform, it is necessary to make the silicon etching amount uniform in the wafer interplanar direction.

For example, in the above-described CVD apparatus 10, when the degree of silicon etching in the upper part of the processing chamber is larger than other parts, the supply flow rate of the pretreatment gas supplied from the long nozzle N1 to the upper part of the processing chamber or The concentration may be made smaller than the supply flow rate or the concentration of the pretreatment gas supplied to the other portion, or the gas kind of the pretreatment gas supplied from the long nozzle N1 to the upper portion of the processing chamber may be different from the gas kind supplied to the other portion.

Next, when the degree of contamination in the lower part of the process chamber is large, the silicon etching amount when the flow rate ratio of chlorine gas and hydrogen gas and the flow rate ratio of silane gas and chlorine gas supplied from the short nozzle N5 to the process chamber lower part are changed. The experiments performed to identify the differences between are described.

Experiment was performed using the 1st evaluation apparatus of FIG.

That is, using the 1st evaluation apparatus of FIG. 5 (a), the mixed gas of hydrogen gas, silane gas, and chlorine gas was introduced into the furnace as a pretreatment gas, and the wafer was preprocessed.

At the time of pretreatment, there are two flow rate ratios of chlorine gas and hydrogen gas, chlorine / hydrogen = 0.02 and chlorine / hydrogen = 0.1, and the flow rate ratio of silane gas and chlorine gas is silane / chlorine = 0 and silane / chlorine = It was changed to two of 2.5.

The silicon etching amount was measured by providing a monitor wafer in each of the upper region (167th), the center region (89th), and the lower region (11th) of the boat.

8 shows a difference between the monitor wafer positions according to the flow rate ratio of the chlorine gas and the hydrogen gas and the flow rate ratio of the silane gas and the chlorine gas in the silicon etching amount.

In FIG. 8, the horizontal axis represents the monitor wafer position, and the vertical axis represents the silicon etching amount.

According to Fig. 8, the following facts can be seen.

At the time of pretreatment, the silicon etching amount distribution in the wafer interplanar direction becomes more uniform than when chlorine / hydrogen = 0.02 has a flow rate ratio of chlorine gas and hydrogen gas set to chlorine / hydrogen = 0.1.

That is, the lowering the ratio of chlorine gas to hydrogen gas can make the silicon etching amount distribution in the wafer interplanar direction uniform.

Further, at the time of pretreatment, the silicon etch amount distribution in the wafer interplanar direction becomes more uniform than that in the case where the flow rate ratio of silane gas and chlorine gas is set to silane / chlorine = 0 and silane / chlorine = 2.5, and thus silicon etching The amount can be made large overall.

That is, the lowering of the ratio of silane gas to chlorine gas can increase the silicon etching amount in all regions while maintaining the silicon etching amount distribution in the wafer interplanar direction.

From this fact, in order to make the silicon etching amount distribution in the wafer interplanar direction uniform, when the ratio of the chlorine gas to the hydrogen gas is lowered, there is a fear that the silicon etching amount is lowered in all regions and the effect of removing interface impurities is lowered. have.

In such a case, since the silicon etching amount can be increased in all regions by lowering the ratio of silane gas to chlorine gas, the decontamination effect can be increased in all regions while maintaining the silicon etching amount satisfactorily.

When the degree of silicon etching in the upper and lower portions of the processing chamber becomes larger than other portions, the supply flow rate or concentration of the pretreatment gas for supplying the upper and lower portions of the processing chamber to the upper and lower portions in the processing chamber to the other portions, or Silicon etching in the interplanar direction of the wafer, such as to reduce the concentration to an appropriate supply flow rate or concentration, or to change the gas type of the pretreatment gas supplied to the upper and lower parts of the processing chamber from that of the pretreatment gas supplied to the other part. It is also possible to make the degree of.

For example, in the above-mentioned CVD apparatus 10, you may set as follows.

(1) Supply flow rate of the chlorine gas supplied from the long nozzle N1 to the upper part in the process chamber, Supply flow rate of the chlorine gas supplied from the long nozzle N2 to the center upper part in the process chamber, and center lower part in the process chamber from the long nozzle N3. The flow rate of the chlorine gas supplied to the process chamber, the supply flow rate of the chlorine gas supplied from the long nozzle N4 to the process chamber bottom, and the supply flow rate of the chlorine gas supplied from the short nozzle N5 to the process chamber lower are 50sccm, 40sccm, 30sccm, 40 sccm, 60 sccm.

(2) The concentration of chlorine gas supplied from the long nozzle N1 to the upper part of the process chamber, the concentration of the chlorine gas supplied from the long nozzle N2 to the center upper part of the process chamber, and the supply from the long nozzle N3 to the center lower part of the process chamber. The concentration of chlorine gas to be supplied to the process chamber bottom from the long nozzle N4, the concentration of the chlorine gas to be supplied to the process chamber lower from the short nozzle N5 is 20%, 10%, 5%, and 10, respectively. % And 30%.

(3) The pretreatment gas supplied to the upper part in a process chamber from the long nozzle N1 as a mixed gas of hydrogen gas and chlorine gas, and the pretreatment gas supplied to the center upper part in a process chamber from the long nozzle N2, and the long nozzle N3. The pretreatment gas supplied from the long chamber N4 to the bottom of the process chamber from the long nozzle N4 as a mixed gas of hydrogen gas, silane gas and chlorine gas, and supplied from the short nozzle N5 to the process chamber bottom. The pretreatment gas is a mixed gas of hydrogen gas and chlorine gas.

In this way, the degree of silicon etching in the wafer interplanar direction can be made uniform by varying the supply flow rate, concentration, or type of the pretreatment gas for each nozzle in accordance with the degree of silicon etching amount. The film thickness distribution can be made uniform.

In addition, this invention is not limited to the said embodiment, Needless to say that a various change is possible in the range which does not deviate from the summary.

For example, the long nozzle is not limited to using a nozzle in which the gas ejection port is opened so as to eject gas upward at the tip of the nozzle as in the above-described embodiment, and a plurality of gas ejection ports are provided on the nozzle tube wall as shown in FIG. 9. In addition, you may use the nozzle which opened so that gas may be blown toward a horizontal direction.

In this case, it is good to provide the gas blowing holes H1-H4 provided in each long nozzle N1-N4 in the place which does not overlap in a vertical direction as shown in FIG. In FIG. 9, five gas ejection openings are provided at equal intervals at the tip of each long nozzle, and the gas ejection holes H1 to H4 of the long nozzles N1 to N4 are also spaced at equal intervals. The example which installed the gas ejection opening in the whole long nozzle at equal intervals is shown. By arrange | positioning the gas blowing holes H1-H4 of each long nozzle N1-N4 in this way, pretreatment gas can be supplied uniformly to the whole furnace.

In addition, the magnitude | size (diameter), airflow, and pitch of gas blowing hole H1-H4 may vary with a place.

In the above embodiment, a case where a polycrystalline silicon film or a single crystal silicon film is formed on a wafer has been described. However, the present invention is not limited thereto, but an amorphous film, or a doped single crystal film, It can also be applied to the formation of a polycrystalline film, amorphous film, nitride film, oxide film, or metal film.

In the said embodiment, although the CVD apparatus was demonstrated, this invention is not limited to this, It is applicable to the whole substrate processing apparatus.

In particular, the present invention can be applied to the case where it is necessary to form a high quality interface between the substrate and the thin film, and excellent effects can be obtained.

Below, a preferable aspect is appended.

(1) a step of bringing a plurality of substrates into a reaction vessel comprising a process tube and a manifold supporting the same, and arranging the plurality of substrates in the reaction vessel;

Performing pretreatment on the plurality of substrates by flowing a pretreatment gas from the manifold side in the reaction vessel toward the process tube side;

Performing a main processing on the plurality of substrates on which the pretreatment has been performed by flowing the main processing gas from the manifold side in the reaction container toward the process tube side;

And carrying out the plurality of substrates after the main treatment from the reaction vessel,

In the step of performing the pretreatment, a pretreatment gas is supplied from at least one place in a region corresponding to the manifold and from at least one top in a region corresponding to a substrate array region.

(2) bringing a plurality of substrates into a reaction vessel and arranging the plurality of substrates in the reaction vessel;

Performing pretreatment on the plurality of substrates by flowing a pretreatment gas into the reaction vessel;

Performing a main processing on the plurality of substrates on which the pretreatment has been performed by flowing the main processing gas into the reaction vessel;

And carrying out the plurality of substrates after the main treatment from the reaction vessel,

In the step of performing the pretreatment, a method of manufacturing a semiconductor device, wherein the pretreatment gas is supplied from at least one location in a region that is lower than the substrate array region and at least one downstream end in a region corresponding to the substrate array region. .

(3) bringing a plurality of substrates into a reaction vessel and arranging the plurality of substrates in the reaction vessel;

Performing pretreatment on the plurality of substrates by flowing a pretreatment gas into the reaction vessel;

Performing a main processing on the plurality of substrates on which the pretreatment has been performed by flowing the main processing gas into the reaction vessel;

And carrying out the plurality of substrates after the main treatment from the reaction vessel,

In the step of performing the pretreatment, a method of manufacturing a semiconductor device, wherein the pretreatment gas is supplied from at least one place in a region below the substrate array region and from at least one upper portion in a region corresponding to the substrate array region.

(4) bringing the substrate into the reaction vessel;

Performing pretreatment on the substrate in the reaction vessel;

Performing the main processing on the substrate subjected to the pretreatment in the reaction vessel;

Carrying out the substrate after the main treatment from the reaction vessel;

In the step of performing the pretreatment, a method of manufacturing a semiconductor device in which a pretreatment gas is supplied from a plurality of places in the processing chamber, and at a different location from at least one of the plurality of places, the supply flow rate, concentration, or type of the pretreatment gas is different. .

(5) bringing the substrate into the reaction vessel;

Performing pretreatment on the substrate in the reaction vessel;

Performing the main processing on the substrate subjected to the pretreatment in the reaction vessel;

Carrying out the substrate after the main treatment from the reaction vessel;

In the step of performing the pretreatment, a plurality of kinds of pretreatment gases are supplied from a plurality of places in the processing chamber, and at a different location from at least one of the plurality of places, the supply flow rate ratio or the concentration ratio of the plurality of kinds of pretreatment gases is changed. The manufacturing method of a semiconductor device.

(6) a process tube for processing the substrate;

A manifold supporting the process tube;

A support for arranging and supporting a plurality of substrates in the process tube;

A first nozzle for supplying gas from at least one location in a region corresponding to the manifold;

A second nozzle for supplying gas from at least one upper portion in a region corresponding to the substrate array region in the process tube;

An exhaust passage disposed on a side opposite to the side on which the first nozzle of the process tube is installed and exhausting the inside of the process tube;

The pretreatment gas is supplied from the first nozzle and the second nozzle, flows toward the exhaust passage, pretreatment is performed on the plurality of substrates, the main processing gas is supplied from at least the first nozzle, and the exhaust is exhausted. And a controller which flows toward the furnace and controls the substrate to perform the main processing on the plurality of substrates on which the pretreatment has been performed.

(7) The controller controls the supply flow rate, concentration, or type of the pretreatment gas to be different at the first nozzle and the second nozzle when the pretreatment gas is supplied from the first nozzle and the second nozzle (6). Substrate processing apparatus).

(8) a process tube for processing the substrate;

A manifold supporting the process tube;

A support for arranging and supporting a plurality of substrates in the process tube;

A first nozzle for supplying gas from at least one location in a region corresponding to the manifold;

A second nozzle for supplying gas from a plurality of locations including at least an upper portion in a region corresponding to the substrate array region in the process tube;

An exhaust passage disposed on a side opposite to the side on which the first nozzle of the process tube is installed and exhausting the inside of the process tube;

The pretreatment gas is supplied from the first nozzle and the second nozzle, flows toward the exhaust passage, pretreatment is performed on the plurality of substrates, the main processing gas is supplied from at least the first nozzle, and the exhaust is exhausted. And a controller which flows toward the furnace and controls the substrate to perform the main processing on the plurality of substrates on which the pretreatment has been performed.

(9) When the controller supplies the pretreatment gas from the first nozzle and the second nozzle, the supply flow rate of the pretreatment gas is different from at least one of the gas supply points of the first nozzle and the second nozzle, The substrate processing apparatus of said (8) which controls so that a density | concentration or a kind may differ.

BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a schematic side sectional view showing a CVD apparatus according to a first embodiment of the present invention.

2 is a side sectional view showing a main part thereof.

3 is a sequence flowchart showing a silicon film forming step of the semiconductor device manufacturing method according to the first embodiment of the present invention.

4 is a sequence flowchart showing a silicon film forming step of the semiconductor device manufacturing method according to the second embodiment of the present invention.

5 is a schematic diagram for evaluating the decontamination effect, in which (a) shows a case by the first evaluation device, and (b) shows a case by the second evaluation device.

Figure 6 is a graph showing the difference by the number of feed gas system of the decontamination effect.

7 is a graph showing the difference in interfacial oxygen density when the flow rate ratio of chlorine gas and hydrogen gas is changed.

8 is a graph showing the difference in silicon etching amount by the flow rate ratio of chlorine gas and hydrogen gas and the flow rate ratio of silane gas and chlorine gas.

9 is a schematic side sectional view of a CVD apparatus according to a second embodiment of the present invention.

10A is a piping diagram showing an example of a first supply system.

10 (b) is a piping diagram showing an example of a second supply system.

<Description of Drawing Major Symbols>

1: wafer (substrate)

10: CVD apparatus (CVD apparatus with a preliminary chamber, substrate processing apparatus)

11: ore 12: reserve room

13: wafer carrying in and out exit 14: gate valve

15: boat carrying in and out 16: shutter

17: exhaust line 18: valve

19: mechanical booster pump 20: dry pump

21: nitrogen gas supply line 22: mass flow controller

23: nitrogen gas source 24: boat elevator

25: guide rail 26: feed screw shaft

27: motor 28: lifting body

29: arm 30: seal cap

31: O-ring 32: rotating mechanism

33: axis of rotation 34: boat

35: heat insulating plate 36: drive control unit

37: electrical wiring 40: reactor

41: heater base 42: heater

43: process tube 44: outer tube

45: inner tube 46: processing chamber

47: cylindrical space 48: O-ring

49: manifold 50: temperature sensor

51: temperature control unit 52: electrical wiring

53 exhaust pipe 54 pressure sensor

55 pressure adjustment device 56 pressure control unit

57: electrical wiring 58: gas flow control unit

59: electrical wiring 60: main controller

61: controller N1: first long nozzle

N2: second long nozzle N3: third long nozzle

N4: fourth long nozzle N5: short nozzle

L1 ~ L5: Gas Supply Line M1 ~ M5: Gas Flow Controller

G1 ~ G5: Gas supply source H1 ~ H4: Gas ejection hole

Claims (9)

Placing a plurality of substrates into a reaction vessel comprising a process tube and a manifold supporting the process tube and arranging the plurality of substrates in the reaction vessel; Performing a pretreatment on the plurality of substrates by flowing a pretreatment gas from the manifold side in the reaction vessel toward the process tube side; Performing a main processing on the plurality of substrates on which the pretreatment has been performed by flowing a main processing gas from the manifold side in the reaction vessel toward the process tube side; Removing the plurality of substrates after the main treatment from the reaction vessel Including, In the step of performing the pretreatment, a pretreatment gas is supplied from at least one place in a region corresponding to the manifold and from at least one top in a region corresponding to a substrate array region. Bringing a plurality of substrates into a reaction vessel and arranging the plurality of substrates in the reaction vessel; Performing pretreatment on the plurality of substrates by flowing a pretreatment gas into the reaction vessel; Performing a main treatment on the plurality of substrates on which the pretreatment has been performed by flowing the main processing gas into the reaction vessel; Removing the plurality of substrates after the main treatment from the reaction vessel Including, In the step of performing the pretreatment, a method of manufacturing a semiconductor device, wherein the pretreatment gas is supplied from at least one location in a region that is lower than the substrate array region and at least one downstream end in a region corresponding to the substrate array region. . Bringing a plurality of substrates into a reaction vessel and arranging the plurality of substrates in the reaction vessel; Performing pretreatment on the plurality of substrates by flowing a pretreatment gas into the reaction vessel; Performing a main treatment on the plurality of substrates on which the pretreatment has been performed by flowing the main processing gas into the reaction vessel; Removing the plurality of substrates after the main treatment from the reaction vessel Including, In the step of performing the pretreatment, a method of manufacturing a semiconductor device, wherein the pretreatment gas is supplied from at least one place in a region below the substrate array region and from at least one upper portion in a region corresponding to the substrate array region. Bringing the substrate into the reaction vessel; Performing pretreatment on the substrate in the reaction vessel; Performing the main treatment on the substrate on which the pretreatment has been performed in the reaction vessel; Step of carrying out the board | substrate after the said main process from the said reaction container Including, In the step of performing the pretreatment, a method of manufacturing a semiconductor device in which a pretreatment gas is supplied from a plurality of places in the processing chamber, and at a different location from at least one of the plurality of places, the supply flow rate, concentration, or type of the pretreatment gas is different. . Bringing the substrate into the reaction vessel; Performing pretreatment on the substrate in the reaction vessel; Performing the main treatment on the substrate on which the pretreatment has been performed in the reaction vessel; Step of carrying out the board | substrate after the said main process from the said reaction container Including, In the step of performing the pretreatment, a plurality of kinds of pretreatment gases are supplied from a plurality of places in the processing chamber, and at a different location from at least one of the plurality of places, the supply flow rate ratio or the concentration ratio of the plurality of kinds of pretreatment gases is different. The manufacturing method of the semiconductor device. A process tube for processing the substrate, A manifold supporting the process tube; A support for arranging and supporting a plurality of substrates in the process tube; A first nozzle for supplying gas from at least one location in a region corresponding to the manifold; A second nozzle for supplying gas from at least one upper portion in a region corresponding to the substrate array region in the process tube; An exhaust passage disposed on a side opposite to the side on which the first nozzle of the process tube is installed and exhausting the inside of the process tube; The pretreatment gas is supplied from the first nozzle and the second nozzle, flows toward the exhaust passage, pretreatment is performed on the plurality of substrates, the main processing gas is supplied from at least the first nozzle, and the exhaust is exhausted. And a controller which flows toward the furnace and controls to perform the main processing on the plurality of substrates on which the pretreatment has been performed. The method of claim 6, wherein the controller, when supplying the pretreatment gas from the first nozzle and the second nozzle, to control the supply flow rate, concentration or type of the pretreatment gas to be different in the first nozzle and the second nozzle. Substrate processing apparatus. A process tube for processing the substrate, A manifold supporting the process tube; A support for arranging and supporting a plurality of substrates in the process tube; A first nozzle for supplying gas from at least one location in a region corresponding to the manifold; A second nozzle for supplying gas from a plurality of locations including at least an upper portion in a region corresponding to the substrate array region in the process tube; An exhaust passage disposed on a side opposite to the side on which the first nozzle of the process tube is installed and exhausting the inside of the process tube; The pretreatment gas is supplied from the first nozzle and the second nozzle, flows toward the exhaust passage, pretreatment is performed on the plurality of substrates, the main processing gas is supplied from at least the first nozzle, and the exhaust is exhausted. And a controller which flows toward the furnace and controls the substrate to perform the main processing on the plurality of substrates on which the pretreatment has been performed. The said controller, when supplying a pretreatment gas from the said 1st nozzle and a said 2nd nozzle, is a site different from at least one of the gas supply parts of a said 1st nozzle and a 2nd nozzle of a pretreatment gas. Substrate processing apparatus for controlling the supply flow rate, concentration or type to be different.

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