SUBSTRATE PROCESSING APPARATUS, SUBSTRATE HOLDER, METHOD OF MANUFACTURING SEMICONDUCTOR DEVICE, AND RECORDING MEDIUM

There are provided a substrate holder that holds a plurality of substrates, a reaction tube that houses the substrate holder, a gas supplier that has a plurality of supply holes corresponding one-to-one to the plurality of substrates and supplies gas to the plurality of substrates, and a plurality of plates provided in substantially parallel to the plurality of substrates, in which at least part of each of the plurality of plates is disposed between the gas supplier and the substrate holder.

BACKGROUND

Field

The present disclosure relates to a substrate processing apparatus, a substrate holder, a method of manufacturing a semiconductor device, and a recording medium.

Description of the Related Art

There is a substrate processing apparatus that forms, with a substrate holder holding substrates on a multiple-stage basis in a processing furnace, a film on the surface of each substrate.

SUMMARY

A substrate holder used in such a substrate processing apparatus as described above has a plate disposed between substrates in order to inhibit an ununiform flow of processing gas due to a prop, leading to an improvement in substrate in-plane uniformity.

However, such a conventional substrate processing apparatus has an inadequate rate of reach of processing gas supplied laterally to the substrate holder onto a wafer (inadequate efficiency of supply). Thus, there is room for improvement.

According to an embodiment of the present disclosure, there is provided a technology including:a substrate holder that holds a plurality of substrates;a reaction tube that houses the substrate holder;a gas supplier that has a plurality of supply holes corresponding one-to-one to the plurality of substrates and supplies gas to the plurality of substrates; anda plurality of plates provided in substantially parallel to the plurality of substrates, in whichat least part of each of the plurality of plates is disposed between the gas supplier and the substrate holder.

DETAILED DESCRIPTION

Embodiment of the Present Disclosure

An embodiment of the present disclosure will be described below mainly with reference toFIGS.1to7. Note that the drawings used in the following description are all schematic and thus, for example, the dimensional relationship between each constituent element and the ratio between each constituent element illustrated in the drawings do not necessarily coincide with realities. In addition, for example, a plurality of drawings does not necessarily coincide with each other in the dimensional relationship between each constituent element or in the ratio between each constituent element.

(1) Configuration of Substrate Processing Apparatus

As illustrated inFIG.1, a processing furnace202includes a heater207serving as a temperature regulator (heater). The heater207is cylindrical in shape and is vertically installed with support by a holding plate. The heater207further functions as an activator (exciter) that thermally activates (excites) gas.

Inside the heater207, a reaction tube203is provided concentrically with the heater207. The reaction tube203is formed of a heat-resistant material, such as quartz (SiO 2) or silicon carbide (SiC). The reaction tube203is cylindrical in shape with its upper end occluded and its lower end open, and has a tubular side face coaxial with a rotary shaft255described later, a top, and a space enclosed with the side face and the top. Below the reaction tube203, a manifold209is provided concentrically with the reaction tube203. The manifold209is formed of a metal material, such as stainless steel (SUS), and is cylindrical in shape with its upper end and lower end open. The manifold209has an upper end portion engaging with the lower end portion of the reaction tube203and thus supports the reaction tube203. An O-ring220aserving as a gasket is provided between the manifold209and the reaction tube203. The reaction tube203is vertically installed, similarly to the heater207. Mainly, with the reaction tube203and the manifold209, a process container (reaction container) is achieved. The process container has a cylindrical hollow portion serving as a process chamber201. The process chamber201is capable of housing a wafer200serving as a substrate. Processing is performed to such a wafer200in the process chamber201.

In the process chamber201, nozzles249aand249bserving, respectively, as first and second feeders are provided, in which the nozzles249aand249bpenetrate through the side wall of the manifold209. The nozzles249aand249bare also referred to as first and second nozzles, respectively. The nozzles249aand249bare each formed of a heat-resistant material, such as quartz or SiC. The nozzles249aand249bhave, respectively, gas supply pipes232aand232bconnected thereto. The nozzles249aand249bare independent from each other and are provided adjacently to each other.

The gas supply pipe232ais provided with a mass flow controller (MFC)241aserving as a flow rate controller and a valve243aserving as an on/off valve in the order from the upstream side of a gas flow. The gas supply pipe232bis provided with a mass flow controller (MFC)241bserving as a flow rate controller and a valve243bserving as an on/off valve in the order from the upstream side of a gas flow. A gas supply pipe232cis connected to the downstream side of the valve243aof the gas supply pipe232a.A gas supply pipe232dis connected to the downstream side of the valve243bof the gas supply pipe232b.The gas supply pipe232cis provided with an MFC241cand a valve243cin the order from the upstream side of a gas flow. The gas supply pipe232dis provided with an MFC241dand a valve243din the order from the upstream side of a gas flow. The gas supply pipes232ato232dare each formed of a metal material, such as SUS.

As illustrated inFIG.2, the annular space in plan view between the inner wall of the reaction tube203and a wafer200is provided with the nozzles249aand249beach extending upward in the direction of an array of wafers200along the inner wall of the reaction tube203from the lower portion to upper portion of the inner wall. That is, the nozzles249aand249bare each provided, in a lateral region horizontally surrounding a wafer array region in which wafers200are arrayed, along the wafer array region. The nozzle249ahas a side face provided with a gas supply hole250aserving as a supply hole for gas supply, and the nozzle249bhas a side face provided with a gas supply hole250bserving as a supply hole for gas supply. The gas supply holes250aand250bare each open opposite (facing) an exhaust port233in plan view, enabling gas supply to the wafer200. Such a plurality of gas supply holes250aand a plurality of gas supply holes250bare provided from the lower portion to upper portion of the reaction tube203.

Source gas serving as processing gas is supplied from the gas supply pipe232ainto the process chamber201through the MFC241a,the valve243a,and the nozzle249a.

Reactant gas serving as processing gas is supplied from the gas supply pipe232binto the process chamber201through the MFC241b,the valve243b,and the nozzle249b.

From the gas supply pipe232cinto the process chamber201, an inert gas serving as processing gas is supplied through the MFC241c,the valve243c,the gas supply pipe232a,and the nozzle249a.From the gas supply pipe232dinto the process chamber201, an inert gas serving as processing gas is supplied through the MFC241d,the valve243d,the gas supply pipe232b,and the nozzle249b.

For example, with the gas supply pipes232ato232dand the nozzles249aand249b,achieved is a gas supplier that supplies gas parallel to the surface of a wafer200to discharge the gas to the central axis.

Mainly, with the gas supply pipe232a,the MFC241a,and the valve243a,a source-gas supply system is achieved. Mainly, with the gas supply pipe232b,the MFC241b,and the valve243b,a reactant-gas supply system is achieved. Mainly, with the gas supply pipes232cand232d,the MFCs241cand241d,and the valves243cand243d,an inert-gas supply system is achieved.

Here, the source gas and the reactant gas act as film-forming gas and thus the source-gas supply system and the reactant-gas supply system can be referred to as a film-forming-gas supply system.

Any or all of the various supply systems described above may be provided as an integrated supply system248including, for example, the valves243ato243dand the MFCs241ato241dintegrated. The integrated supply system248is connected to the gas supply pipes232ato232dsuch that a controller121described later controls the operations of supplying various types of gas into the gas supply pipes232ato232d,namely, the on/off operations of the valves243ato243dor the flow rate regulating operations with the MFCs241ato241d.The integrated supply system248is provided as a single integrated unit or a splittable integrated unit such that the integrated supply system248can be attached to or detached from the gas supply pipes232ato232dper integrated unit. Thus, for example, maintenance, replacement, or addition per integrated unit can be performed to the integrated supply system248.

The side wall of the reaction tube203has a lower portion provided with the exhaust port233for exhausting the atmosphere in the process chamber201. As illustrated inFIG.2, in plan view, the exhaust port233is located opposite (facing) the nozzles249aand249b(gas supply holes250aand250b) across the wafer200. The exhaust port233may be provided along the side wall of the reaction tube203from the lower portion to upper portion of the side wall, namely, along the wafer array region. The exhaust port233is in connection with an exhaust pipe231. The exhaust pipe231is in connection with a vacuum pump246serving as a vacuum exhauster through a pressure sensor245serving as a pressure detector that detects the pressure in the process chamber201and an auto pressure controller (APC) valve244serving as a pressure regulator. With the vacuum pump246in operation, the APC valve244opens to vacuum-exhaust the process chamber201or shuts to stop the vacuum exhaust. Furthermore, with the vacuum pump246in operation, the APC valve244regulates its degree of valve opening, based on pressure information detected by the pressure sensor245, so that the pressure in the process chamber201can be regulated. Mainly, with the exhaust pipe231, the APC valve244, and the pressure sensor245, an exhaust system (gas exhauster) is achieved. The vacuum pump246may be included in the exhaust system.

Below the manifold209, provided is a seal cap219serving as a furnace opening lid capable of hermetically occluding the opening at the lower end of the manifold209. The seal cap219is formed of a metal material, such as SUS, and is discoid in shape. The seal cap219has an upper face provided with an O-ring220bserving as a gasket that abuts on the lower end of the manifold209. Below the seal cap219, provided is a rotator267that rotates a boat217described later. The rotary shaft255of the rotator267penetrates through the seal cap219and is in connection with the boat217. The rotator267rotates the boat217to rotate wafers200. The seal cap219rises or falls vertically due to a boat elevator115serving as a lifter provided outside the reaction tube203. The boat elevator115serves as a conveyer that raises or lowers the seal cap219to load (convey) wafers200into or unload (convey) the wafers200from the process chamber201.

Below the manifold209, provided is a shutter219sserving as a furnace opening lid capable of hermetically occluding the opening at the lower end of the manifold209with the boat217unloaded from the process chamber201due to lowering of the seal cap219. The shutter219sis formed of a metal material, such as SUS, and is discoid in shape. The shutter219shas an upper face provided with an O-ring220cserving as a gasket that abuts on the lower end of the manifold209. The on/off operation (e.g., lifting operation or turning operation) of the shutter219sis controlled by a shutter on/off switch115s.

The boat217serving as a substrate holder holds a plurality of wafers200, such as 25 to 200 wafers200, such that the wafers200, of which the postures are kept horizontal and the centers are aligned, are arrayed vertically on a multiple-stage basis, namely, at intervals, though to be described in detail later. The boat217is formed of a heat-resistant material, such as quartz or SiC. The boat217has a lower portion at which heat insulating plates218formed of a heat-resistant material, such as quartz or SiC, are supported on a multiple-stage basis.

In the reaction tube203, provided is a temperature sensor263serving as a temperature detector. The degree of energization to the heater207is regulated based on temperature information detected by the temperature sensor263, so that the temperature in the process chamber201has a desired temperature distribution. The temperature sensor263is provided along the inner wall of the reaction tube203.

Next, the boat217will be described in detail withFIG.3.

The boat217includes a bottom plate301ring-shaped, a top plate302discoid in shape, an intermediate plate303discoid in shape provided substantially horizontally between the bottom plate301and the top plate302, and a plurality of props304ato304c(three props in the present embodiment) by which the bottom plate301, the top plate302, and the intermediate plate303are disposed in the vertical direction and are kept substantially horizontal.

The props304ato304care provided with a plurality of separation plates400serving as a plurality of plates in the vertical direction between the top plate302and the intermediate plate303, in which the plurality of separation plates400is kept substantially horizontal.

The plurality of separation plates400is each an annular flat plate and each is, for example, formed of quartz. Each separation plate400has an inner diameter not more than the outer diameter of a wafer200and has an outer diameter larger than the outer diameter of the wafer200. In addition, the outer diameter of each separation plate400is larger than the diameter of a circle corresponding to the radius of gyration of the props304ato304c,namely, the diameter of the circumscribed circle402of the props304ato304c.Thus, part of each separation plate400is disposed outside the circumscribed circle402.

The plurality of separation plates400is each fixed to the props304ato304cby substantially vertical penetration. That is, the plurality of separation plates400is each fixed due to the penetration of the props304ato304c,resulting in integration with the boat217.

The plurality of separation plates400is each fixed to the props304ato304cof which the central axes are located inward by the amount equivalent to the diameter of each of the props304ato304cfrom the outer circumference of each separation plate400and are located outside the inner circumference of each separation plate400. Thus, each separation plate400protrudes by a predetermined amount or more outside the circumscribed circle402of the props304ato304c,such as by an amount not less than the radius of each of the props304ato304c,in other words, by an amount not less than half the width of each of the props304ato304c.

Between each separation plate400, provided is a support pin221serving as a support for holding a wafer200substantially horizontally. From each of the plurality of props304ato304c,such support pins221extend inward, substantially horizontally, such that a wafer200is supported at predetermined intervals (pitches) between an upper separation plate400and a lower separation plate400. Each support pin221is not limited to a projection shaped like a rod and thus may be a semicircular projection formed by cutting off parts not for the support pin221from a round rod for the material of the props304ato304c.

Next, the positional relationship between gas supply holes250aand250b,a separation plate400, and a wafer200will be described in detail.

FIG.4Ais a partial enlarged view of the vicinity of the nozzles249aand249bin the process chamber201.FIG.4Bis a partial enlarged view of the vicinity of gas supply holes250aand250billustrated inFIG.4A.FIG.5is a horizontal sectional view illustrating the positional relationship between gas supply holes250aand250b,a separation plate400, and a wafer200.

The plurality of separation plates400is each disposed between gas supply holes250ain the up-down direction of the gas supply holes250aand between gas supply holes250bin the up-down direction of the gas supply holes250b.Preferably, the plurality of separation plates400is disposed one-to-one between the top plate302and a wafer200, between each wafer200, and between a wafer200and the intermediate plate303, in substantially parallel to the wafers200. Part of each of the plurality of separation plates400is disposed in the space between the nozzles249aand249band the boat217. Such a configuration enables inhibition of a flow of gas in a substantially vertical direction between the nozzles249aand249band the boat217and in the up-down direction.

At the position between each of the plurality of separation plates400, three support pins221hold a wafer200substantially horizontally. That is, a plurality of support pins221holds a plurality of wafers200at predetermined pitches such that each wafer200is located between separation plates400. The distance P1between each wafer200and the lower adjacent separation plate400and the distance P2between each wafer200and the upper adjacent separation plate400are determined in accordance with the type of the end effector of a transferer.

As an example, as illustrated inFIG.4B, the plurality of separation plates400is each disposed, between the upper adjacent wafer200serving as a wafer corresponding to the separation plate400and the lower adjacent wafer200serving as a wafer corresponding to the separation plate400, closer to the upper adjacent wafer200in height than to the lower adjacent wafer200. That is, each separation plate400is provided such that the distance P2to the lower adjacent wafer200is longer than the distance P1to the upper adjacent wafer200. Such a configuration enables an adequate interval between a wafer200and the upper separation plate400to the wafer200and thus is favorable to a suction or Bernoulli's end effector. Alternatively, according to a configuration in which the distance P1is larger than the distance P2, below a wafer200, a space for insertion of the end effector of a transferer that bears and conveys the wafer200is ensured and a space for lifting and conveying the wafer200is ensured above the wafer200.

Between upper and lower adjacent separation plates400, the respective upper ends and lower ends of a gas supply hole250aand a gas supply hole250bare disposed. Between the respective upper ends and lower ends of the gas supply hole250aand the gas supply hole250b,a wafer200is disposed almost at the centers of the gas supply hole250aand the gas supply hole250b.That is, the plurality of gas supply holes250ais each disposed corresponding to the position of the wafer200between the corresponding separation plates400and the plurality of gas supply holes250bis each disposed corresponding to the position of the wafer200between the corresponding separation plates400. Then, gas is supplied from each gas supply hole250ato the corresponding wafer200and gas is supplied from each gas supply hole250bto the corresponding wafer200, followed by formation of a parallel flow of gas on the surface of each wafer200, resulting in efficient gas supply to each of the plurality of wafers200.

Note that the plurality of separation plates400is each annular as described above and each has an opening at its center. That is, the space between upper and lower wafers200is not completely separated. Thus, the pitch between wafers can be kept wide, so that gas flows easily on a wafer200without detouring around the wafer200. At a central portion, which causes a film thin in thickness, in a wafer, a flow channel has its height increasing to the interval between wafers, enabling prevention of a reduction in flow velocity and supply of unreacted gas through the opening at the center of a separation plate400.

Specifically, the inflow of gas from the gas supply holes250aand250bcorresponding to a wafer200branches into two flows of gas that are a flow of gas between the upper side of the corresponding wafer200and the separation plate400directly above the wafer200and a flow of gas between the lower side of the corresponding wafer200and the separation plate400right below the wafer200. Then, the upper flow of gas merges, at the opening at the center of the upper separation plate400, with a flow of gas to the upper adjacent wafer200to the corresponding wafer, and the lower flow of gas merges, at the opening at the center of the lower separation plate400, with a flow of gas to the lower adjacent wafer200to the corresponding wafer.

According to such a configuration, the gas supplied from gas supply holes250aand250bcauses an increase in the quantity of gas flowing between wafers200, leading to an increase in the gas inflow rate that is the rate at which the gas supplied from gas supply holes250aand250bflows between wafers200. Use of a separation plate400enables a smaller surface area and less gas consumption than use of a discoid separation plate.

In the process chamber201, the plurality of separation plates400is fixed and arrayed at predetermined intervals (pitches) by the props304ato304c,orthogonally to the rotary shaft255and concentrically with the rotary shaft255. That is, the center of each separation plate400is aligned with the central axis of the boat217. In addition, the central axis of the boat217coincides with the central axis of the reaction tube203and the rotary shaft255. That is, the plurality of separation plates400is supported at constant intervals by the props304ato304cof the boat217with their postures kept horizontal and their centers aligned with each other, in which the stack direction corresponds to the axial direction of the reaction tube203. That is, the boat217including the plurality of separation plates400is housed rotatably in the reaction tube203.

Each of the plurality of separation plates400has, as illustrated inFIG.5, a width W occupying between the nozzles249aand249band the circumscribed circle402that is a circle corresponding to the radius of gyration of the props304ato304cin horizontal sectional view, larger than the width of each of the props304ato304cof the boat217(diameter D of each of the props304ato304cinFIG.5) or the distance L between the circumscribed circle402and the end portion of the wafer200.

That is, at least part of each of the plurality of separation plates400is disposed outside the circumscribed circle402of the props304ato304cin the space between the nozzles249aand249band the boat217, and the plurality of separation plates400is fixed to the props304ato304c,in substantially parallel with the plurality of wafers200.

According to such a configuration, each separation plate400protrudes by a predetermined amount or more outside the props304ato304c,enabling inhibition of a flow of gas in a substantially vertical direction between the nozzles249aand249band the boat217and in the up-down direction. Therefore, a reduction can be made in loading effect with an improvement in the efficiency of gas supply to each wafer200. In particular, the gas supplied from the gas supply holes250aand250bcan be inhibited from flowing down due to hitting against the props304ato304c.

This results in an increase in the inflow rate of gas onto each wafer200, so that constancy or improvement can be achieved in in-plane uniformity. An improvement can be made in inter-plane uniformity with inhibition of diffusion in the up-down direction of each wafer200.

As illustrated inFIG.6, a controller121serves as a computer including a central processing unit (CPU)121a,a random access memory (RAM)121b,a memory121c,and an I/O port121d.The RAM121b,the memory121c,and the I/O port121dare capable of data exchange with the CPU121athrough an internal bus121e.An input/output device122serving, for example, as a touch panel is connected to the controller121.

The memory121cis achieved, for example, with a flash memory, a hard disk drive (HDD), or a solid state drive (SSD). In the memory121c,readably stored are a control program for controlling the operation of the substrate processing apparatus and a process recipe including procedures of substrate processing and conditions therefor described later. The process recipe functions as a program that causes the controller121to perform each procedure in substrate processing described later to obtain a predetermined result. Hereinafter, the process recipe and the control program are also collectively and simply referred to as a program. The process recipe is also simply referred to as a recipe. In the present specification, in some cases, the term “program” indicates only the recipe, only the control program, or both of the recipe and the control program. The RAM121bserves as a memory area (work area) in which the program or data read by the CPU121ais temporarily stored.

The I/O port121dis connected to, for example, the MFC241ato241d,the valves243ato243d,the pressure sensor245, the APC valve244, the vacuum pump246, the temperature sensor263, the heater207, the rotator267, the boat elevator115, and the shutter on/off switch115sdescribed above.

The CPU121ais capable of reading the control program from the memory121cto execute the control program and reading the recipe from the memory121cin response to an operation command input through the input/output device122. In accordance with the content of the read recipe, the CPU121ais capable of controlling the flow rate regulating operations of various types of gas with the MFC241ato241d,the on/off operations of the valves243ato243d,the on/off operation of the APC valve244, the pressure regulating operation with the APC valve244based on the pressure sensor245, the startup or shutdown of the vacuum pump246, the temperature regulating operation of the heater207based on the temperature sensor263, the rotation of the boat217with the rotator267and the rotational rate regulating operation of the rotator267, the lifting operation of the boat217with the boat elevator115, and the on/off operation of the shutter219swith the shutter on/off switch115s.

The controller121can be achieved due to installation of the above program stored in an external memory123into the computer. Examples of the external memory123include a magnetic disk, such as an HDD, an optical disc, such as a CD, a magneto-optical disc, such as an MO, and a semiconductor memory, such as a USB memory or an SSD. The memory121cand the external memory123each serve as a computer-readable recording medium. Hereinafter, such memories are collectively and simply referred to as a recording medium. In the present specification, in some cases, the term “recording medium” indicates only the memory121c,only the external memory123, or both thereof. Note that the program may be provided to the computer, for example, through the internet or a dedicated line, instead of the external memory123.

(2) Substrate Processing Process

An exemplary sequence of substrate processing of forming a film on the surface of a wafer200serving as a substrate will be described mainly withFIG.7as a partial process in the process of manufacturing a semiconductor device with the substrate processing apparatus described above. In the following description, the controller121controls the operation of each constituent of the substrate processing apparatus.

In the present specification, in some cases, the term “wafer” means a wafer itself, or means a laminate of a wafer and a predetermined layer or film formed on the surface of the wafer. In the present specification, in some cases, the term “surface of a wafer” means the surface of a wafer itself or means the surface of a predetermined layer or the like formed on a wafer. In the present specification, in some cases, the expression “form a predetermined layer on a wafer” means that directly form a predetermined layer on the surface of a wafer itself or means that form a predetermined layer on a layer or the like formed on a wafer. In the present specification, the term “substrate” is synonymous with the term “wafer”.

Wafer Charge and Boat Load

When a plurality of wafers200is charged to the boat217(wafer charge), the shutter on/off switch115smoves the shutter219s,so that the opening at the lower end of the manifold209is exposed (shutter open). After that, as illustrated inFIG.1, the boat elevator115lifts up the boat217supporting the plurality of wafers200, to load the boat217into the process chamber201(boat load), so that the plurality of wafers200is housed in the process chamber201. In this state, the lower end of the manifold209is sealed by the seal cap219through the O-ring220b.

Pressure Regulation and Temperature Regulation

After that, the vacuum pump246performs vacuum exhaust (decompression exhaust) such that the process chamber201has its inside, namely, the space in which the wafers200are present, at a desired pressure (desired degree of vacuum). In this case, the pressure sensor245measures the pressure in the process chamber201and then the APC valve244is feedback-controlled based on information on the measured pressure. The heater207performs heating such that the wafers200in the process chamber201have a desired process temperature. In this case, based on information on the temperature detected by the temperature sensor263, the degree of energization to the heater207is feedback-controlled such that a desired temperature distribution is acquired in the process chamber201. The rotator267starts to rotate the wafers200. The exhaust in the process chamber201, the heating to the wafers200, and the rotation of the wafers200each continue at least until the processing to the wafers200finishes.

After that, the following first to fourth steps are performed in this order. Each step will be described below.

First Step (Source Gas Supply)

The valve243ais opened to supply source gas into the gas supply pipe232a.The source gas is supplied into the process chamber201through the nozzle249awhile being regulated in flow rate by the MFC241aand then is exhausted through the exhaust port233. In this case, the source gas is supplied to the surface of each wafer200(source gas supply). In this case, the valves243cand243dmay be opened to supply inert gases, such as nitrogen (N 2), into the process chamber201through the nozzles249aand249b,respectively.

The supply of the source gas to the surface of each wafer200causes, on the surface of each wafer200, formation of a first layer including an element contained in the source gas.

As the source gas, for example, an Si-and-halogen containing gas can be used. Halogen includes, for example, chlorine (Cl), fluorine (F), bromine (Br), and iodine (I).

Second Step (Purge)

After the elapse of a predetermined time from the start of supply of the source gas, the valve243ais shut to stop the supply of the source gas. In this case, with the exhaust pipe231having the APC valve244opened, the vacuum pump246vacuum-exhausts the process chamber201to remove the residual gas on each wafer200, so that the unreacted source gas remaining in the process chamber201is eliminated (exhausted) from the process chamber201(purge). In this case, the valves243cand243dare opened to supply inert gases serving as purge gas into the process chamber201. The inert gases act as purge gas to remove the residual gas from the surface of each wafer200, resulting in an enhancement in the effect of eliminating, from the process chamber201, the unreacted source gas remaining in the process chamber201.

Third Step (Reactant Gas Supply)

After the elapse of a predetermined time from the start of the purge, the valve243bis opened to supply reactant gas into the gas supply pipe232b.The reactant gas is supplied into the process chamber201through the nozzle249bwhile being regulated in flow rate by the MFC241band then is exhausted through the exhaust port233. In this case, the reactant gas is supplied to the surface of each wafer200(reactant gas supply). In this case, the valves243cand243dmay be opened to supply inert gases into the process chamber201through the nozzles249aand249b,respectively.

The supply of the reactant gas to the surface of each wafer200enables reaction of at least part of the first layer formed on the surface of each wafer200. Thus, a second layer resulting from reaction of the first layer is formed on the surface of each wafer200.

As the reactant gas, a gas that reacts with the source gas is used. Note that, for formation of a film such as an oxide film, an oxidation gas containing oxygen (O) can be used as the reactant gas. For formation of a film such as a nitride film, a nitridation gas containing nitrogen (N) can be used as the reactant gas.

Fourth Step (Purge)

After the elapse of a predetermined time from the start of supply of the reactant gas, the valve243bis shut to stop the supply of the reactant gas. Then, based on a processing procedure and processing conditions similar to those for the purge in the second step, for example, the gas remaining in the process chamber201is eliminated (exhausted) from the process chamber201(purge).

Predetermined Number of Times of Performance

A cycle in which the first to fourth steps described above are performed not simultaneously, namely, asynchronously, is repeated a predetermined number of times (n times: n is an integer of one or more) to form a film having a predetermined thickness on the surface of each wafer200. Preferably, the cycle described above is repeated a plurality of times. That is, preferably, the cycle described above is repeated a plurality of times until a film has a desired thickness due to a stack of second layers, in which the thickness of the second layer formed per single cycle is smaller than the desired thickness.

After-Purge and Atmospheric Pressure Restoration

Respective inert gases through the nozzles249aand249bare supplied into the process chamber201and then are exhausted through the exhaust port233. The inert gases supplied through the nozzles249aand249bact as purge gas. Thus, a purge is conducted in the process chamber201, so that the residual gas and any reaction by-product in the process chamber201are removed from the process chamber201(after-purge). After that, the atmosphere in the process chamber201is replaced with the inert gases (Inert gas replacement), so that the pressure in the process chamber201is restored to the normal pressure (atmospheric pressure restoration).

Boat Unload and Wafer Discharge

After that, the boat elevator115lowers the seal cap219, resulting in exposure of the opening at the lower end of the manifold209. Then, the processed wafers200that the boat217has supported are unloaded outward from the reaction tube203through the lower end of the manifold209(boat unload). After the boat unload, the shutter219sis moved, so that the opening at the lower end of the manifold209is sealed with the shutter219sthrough the O-ring220c(shutter close). After being unloaded outward from the reaction tube203, the processed wafers200are taken out from the boat217(wafer discharge).

(3) Modified Examples

The separation plates400or the gas supplier in the embodiment described above can be modified as in the following modified examples. Unless otherwise specified, the configuration in each modified example is similar to the configuration in the embodiment described above, and thus the description thereof will be omitted.

Modified Example 1

In Modified Example 1, as a plurality of separation plates, as illustrated inFIG.8, separation plates500alarge in diameter and separation plates500bsmall in diameter are used, instead of the separation plates400identical in diameter in the embodiment described above. The separation plates500alarge in diameter and the separation plates500bsmall in diameter are different in outer diameter but are identical in inner diameter. The separation plates500aand the separation plates500bare disposed in substantially parallel to wafers200, in which part of each separation plate500aand part of each separation plate500bare disposed in the space between nozzles249aand249band a boat217.

That is, the separation plates500aannular in shape and large in diameter and the separation plates500bannular in shape and small in diameter are alternately disposed in the vertical direction and are fixed to props304ato304c.Then, the wafers200are each placed on support pins221disposed directly above a separation plate500bsmall in diameter. That is, the wafers200are not placed on support pins221disposed directly above any separation plate500alarge in diameter. In other words, each separation plate500bsmall in diameter is adjacent above to the corresponding separation plate500alarge in diameter. Each wafer200is adjacent above to the corresponding separation plate500bsmall in diameter. Each separation plate500alarge in diameter is adjacent above to the corresponding wafer200. The upper end and lower end of each of gas supply holes250aand250bare disposed corresponding to the position of the wafer200between the corresponding separation plate500alarge in diameter and the corresponding separation plate500bsmall in diameter.

The separation plates500alarge in diameter each adjacent above to the wafer200and the separation plates500bsmall in diameter each adjacent below to the wafer200enable, with rectification of a flow of gas, suppression of the quantity of gas consumption due to the separation plates500aand500b.Regulation of the width W of each separation plate500aand the width W of each separation plate500bdisposed outside the circumscribed circle402of the props304ato304cenables an improvement in in-plane uniformity and an improvement in inter-plane uniformity with inhibition of a change in the thickness of a film at the end portion of each wafer200or near the props304ato304c.

Note that the configuration in which the separation plates500bsmall in diameter are annular in shape has been given above, but this is not limiting. Thus, the separation plates500bsmall in diameter may be discoid in shape or may be C-shaped. Alternatively, provided may be crescent-shaped or arc-shaped plates fixed to each of the props304ato304c.The arrangement positions of the separation plates500alarge in diameter and the arrangement positions of the separation plates500bsmall in diameter may be changed with each other. Even in such a case, an effect similar to that in the present Modified Example 1 can be obtained.

Modified Example 2

In Modified Example 2, as a gas supplier, as illustrated inFIG.9, a nozzle249ahaving gas supply holes550aopen obliquely and a nozzle249bhaving gas supply holes550bopen obliquely are used, instead of the nozzle249ahaving the gas supply holes250aopen substantially horizontally and the nozzle249bhaving the gas supply holes250bopen substantially horizontally in the embodiment described above.

That is, the gas supply holes550aand550bare each directed obliquely downward. That is, the gas supply holes550aand550beach supply gas to the surface of a wafer200from obliquely above. The gas supply holes550aand550bare each disposed corresponding to the position of the wafer between separation plates400. Specifically, the upper end and lower end of each of the gas supply holes550aand550bare disposed between the upper face of the corresponding wafer200and the separation plate400adjacent above to the corresponding wafer200. According to such a configuration, the gas supplied obliquely downward from each of the gas supply holes550aand550bis supplied to the upper face of the corresponding wafer200, efficiently. The gas supplied to the lower face of the corresponding wafer200reflects off the separation plate400adjacent below to the corresponding wafer200and then is supplied to the lower adjacent wafer200through the opening at the center of the separation plate400. Thus, a flow of gas between each separation plate400can be regulated, leading to efficient gas supply to each wafer200. An improvement in in-plane uniformity and an improvement in inter-plane uniformity can be made with inhibition of a change in the thickness of a film at the end portion of each wafer200or near props304ato304c.

Note that the configuration in which the gas supply holes550aand550bare each directed obliquely downward has been given above, but this is not limiting. Thus, the gas supply holes550aand550bmay be each directed obliquely upward. That is, the gas supply holes550aand550bmay each supply gas to the surface of the corresponding wafer200from obliquely below. According to such a configuration, the gas supplied obliquely upward from each of the gas supply holes550aand550breflects off the separation plate400adjacent above to the corresponding wafer200and then is supplied to the upper face of the corresponding wafer200. Even in such a case, an effect similar to that in the present Modified Example 2 can be obtained.

Modified Example 3

In Modified Example 3, as illustrated inFIG.10, in addition to the nozzle249ahaving the gas supply holes550aand the nozzle249bhaving the gas supply holes550bin Modified Example 2 described above as a gas supplier, separation plates600are used, instead of the separation plates400. The separation plates600each include a central portion600aannular in shape disposed inside props304ato304cand an outer circumferential portion600bdisposed outside the props304ato304c.The outer circumferential portion600bis angled obliquely upward with respect to the central portion600aand is directed obliquely upward. That is, the respective outer circumferential portions600bof the separation plates600are disposed in the space between the nozzles249aand249band a boat217and the respective central portions600aof the separation plates600are disposed in substantially parallel to wafers200.

That is, the gas supply holes550aand550bare each directed obliquely downward and supply gas to the surface of the corresponding wafer200from obliquely above, similarly to Modified Example 2 described above. Then, the upper end and lower end of each of the gas supply holes550aand550bare disposed corresponding to the position of the wafer200between the outer circumferential portions600bof separation plates600. Thus, a flow of gas between each separation plate600can be regulated, leading to efficient gas supply to each wafer200. A thicker film can be inhibited from being formed at the end portion of each wafer200, so that an improvement can be made in in-plane uniformity. Note that, even in a case where, instead of the gas supply holes550aand550b,the nozzle249ahaving the gas supply holes250aopen substantially horizontally and the nozzle249bhaving the gas supply holes250bopen substantially horizontally described above are used, an effect similar to that in the present Modified Example 3 can be obtained.

Modified Example 4

In Modified Example 4, as a separation plate, as illustrated inFIG.11, separation plates700ato700cof one or more crescent-shaped plates (three in the present Modified Example) are used, instead of such a separation plate400as in the embodiment described above. The separation plates700ato700care each disposed in the space between nozzles249aand249band a boat217, in substantially parallel to wafers200.

The separation plates700ato700care fixed to props304ato304c,respectively. Gas supply holes250aand250bare each disposed corresponding to the position of the wafer200between such separation plates700a,700b,or700c.As above, since the separation plates serving as divisions are disposed near the props where a downward flow of gas occurs easily, a downward flow of gas is inhibited, leading to efficient gas supply to each wafer200. In the present Modified Example 4, the separation plates700ato700cdisposed as divisions are low in internal stress and thus are not easily damaged. The separation plates700ato700ccan be made thin, leading to easy production. Note that, even in a case where the separation plates700ato700care each a circumferentially divided plate, such as an arc-shaped plate, instead of a crescent-shaped plate, a similar effect can be obtained.

Modified Example 5

In Modified Example 5, as illustrated inFIGS.12and13, a reaction tube203includes an outer tube205and an inner tube204. The respective vertical portions of nozzles249aand249bare provided inside a supply chamber201abeing channel-shaped (groove shaped), protruding outward in the radial direction of the inner tube204, and extending in the vertical direction. Then, in a process chamber201, provided are movable separation plates800each fixed to props304ato304c,fixed separation plates900afixed to the nozzle249ain the supply chamber201a,and fixed separation plates900bfixed to the nozzle249bin the supply chamber201a.

The movable separation plates800are each an annular flat plate protruding in a crescent shape near the props304ato304csuch that its width (outer diameter) is wider (larger) near the props304ato304cthan at the others, as illustrated inFIG.12. The movable separation plates800each have its inner diameter larger than the outer diameter of a wafer200and are each fixed substantially perpendicularly to the outer circumferential side of each of the props304ato304c.That is, the movable separation plates800are disposed between the nozzles249aand249band a boat217and are fixed rotatably between the nozzles249aand249band the boat217. The movable separation plates800each include, on its outer circumferential side, a narrow-width portion or cut-away portion enabling passage with avoidance of the fixed separation plates900aand900bdescribed later at the time of loading of the boat217into the inner tube204. In the present example, the portion excluding the crescent-shaped protrusions corresponds to the narrow-width portion, that is, the narrow-width portion or cut-away portion is formed around the props304bto304c.

As illustrated inFIGS.12and13, the fixed separation plates900aare fixed substantially perpendicularly to the nozzle249aserving as a gas supplier and the fixed separation plates900bare fixed substantially perpendicularly to the nozzle249bserving as a gas supplier. The fixed separation plates900aand900bare disposed between the nozzles249aand249band the boat217and are fixed unrotatably between the nozzles249aand249band the boat217. Note that the fixed separation plates900aand900bmay be each fixed to the reaction tube203. As above, the provision of the fixed separation plates900aand900bfixed unrotatably in the process chamber201enables inhibition of a downward flow of gas immediately after supply from gas supply holes250aand250b.

As illustrated inFIG.13, the gas supply holes250aand250bare each disposed between movable separation plates800. The gas supply holes250aare each disposed just above the corresponding fixed separation plate900a,and the gas supply holes250bare each disposed just above the corresponding fixed separation plate900b.That is, each gas supply hole250aand the corresponding fixed separation plate900aare disposed between movable separation plates800, and each gas supply hole250band the corresponding fixed separation plate900bare disposed between movable separation plates800. The fixed separation plates900aand900bextend toward the center of the inner tube204with respect to the inner circumferential face of the inner tube204and are disposed in substantially parallel to the movable separation plates800and wafers200. The gas supply holes250aand250bare each formed corresponding to the position of a wafer200. That is, the movable separation plates800and the fixed separation plates900aand900bare each disposed between the nozzles249aand249band the boat217. According to such a configuration, the gas discharged from each of the gas supply holes250aand250bflows along the corresponding fixed separation plate900aor900band then almost all the gas travels straight to flow onto the surface of the corresponding wafer200. In a case where the gas supply holes250aand250bare each opposed to (face) any of the props304ato304c,the gas having hit against the props304ato304cis rectified to a horizontal flow around the props304ato304cbecause the corresponding movable separation plate800restricts a downward flow of gas. Thus, efficient gas supply can be made to each wafer200.

As illustrated inFIG.13, the movable separation plates800are each disposed, between the upper adjacent wafer200and the lower adjacent wafer200, closer to the lower adjacent wafer200in height than to the upper adjacent wafer200. That is, the distance between each movable separation plate800and the lower adjacent wafer200is shorter than the distance between each movable separation plate800and the upper adjacent wafer200. Thus, below each wafer200, secured is a space for lifting and conveying the wafer200. That is, an adequate interval between a wafer200and the movable separation plate800below the wafer200enables use of a lifting transferer.

Modified Example 6

In Modified Example 6, as a separation plate, as illustrated inFIG.14, a fixed separation plate1000fixed in a reaction tube203is used, instead of such a separation plate400as in the embodiment described above.

That is, the fixed separation plate1000fixed in the reaction tube203is provided near nozzles249aand249b.The fixed separation plate1000has through-holes for the nozzles249aand249b,in which the nozzles249aand249bare provided one-to-one through the through-holes. Such a plurality of fixed separation plates1000is provided in a substantially vertical direction in the reaction tube203, in which each fixed separation plate1000is substantially horizontal. The fixed separation plates1000are each disposed between gas supply holes250aof the nozzle249aand between gas supply holes250bof the nozzle249b.That is, the gas supply holes250aand250bare each disposed between fixed separation plates1000. The fixed separation plates1000each have a part disposed between the nozzles249aand249band a boat217and are each fixed unrotatably between the nozzles249aand249band the boat217. According to such a configuration, an effect similar to that in the embodiment described above is obtained.

Other Embodiments

Various exemplary embodiments and modified examples of the present disclosure have been described above, but the present disclosure is not limited to such embodiments. Thus, any appropriate combination thereof can be provided.

For example, the configuration in which the inner diameter of a separation plate400is not more than the outer diameter of a wafer200has been given in the embodiment described above, but this is not limiting. Thus, the inner diameter of a separation plate400may be larger than the outer diameter of a wafer200. That is, such a separation plate400may be fixed to the props304ato304cwithout being penetrated by the props304ato304c.

The example in which a wafer200is placed on support pins221has been given in the embodiment described above, but this is not limiting. Thus, a wafer200may be placed with the respective support grooves formed on the props304ato304cor a wafer200may be placed on a separation plate.

Note that particular embodiments and modified examples of the present disclosure have been described in detail, but the present disclosure is not limited to such embodiments and modified examples. Thus, it is obvious to those skilled in the art that other various embodiments can be made without departing from the scope of the present disclosure.

According to the present disclosure, an improvement can be made in the efficiency of supply of processing gas with constancy or improvement in in-plane uniformity.