Patent Description:
The present disclosure relates to a reaction tube, a substrate processing apparatus and a method of manufacturing a semiconductor device.

A substrate processing apparatus may be configured to perform a process such as an oxidation process and a diffusion process. According to the substrate processing apparatus, for example, a gas such as a process gas is introduced through a gas introduction port provided at a bottom of a reaction tube of the substrate processing apparatus, and then is supplied into a reaction chamber (also referred to as a "process chamber"). According to Patent Document <NUM> and Patent Document <NUM> described below, a space where the gas is temporarily stored to adjust a pressure of the gas is provided at the reaction tube, and the gas is supplied into the reaction chamber through the space.

According to Patent Document <NUM> described below, a preheating cylinder is provided below a substrate processing region of a substrate retainer and a gas introduction portion of the substrate processing apparatus, and the gas introduced through the gas introduction portion flows upward via the preheating cylinder.

According to Patent Document <NUM> described below, the gas supplied through a pipe disposed below the substrate processing region of the substrate retainer is preheated.

However, the gas introduced through the gas introduction portion may pass through the pipe arranged on a side surface of the substrate processing region without sufficiently heated to a desired temperature. As a result, a temperature of an outer periphery of a lower portion of the substrate processing region may decrease, and thus processing results between substrates accommodated in the substrate processing region may vary.

Described herein is a technique capable of reducing a difference in processing results between substrates arranged in a substrate processing region.

According to one aspect of the technique of the present disclosure, there is provided a reaction tube provided therein with a process chamber and heated by a heater provided therearound including: a gas introduction portion provided at a lower end and through which a process gas is introduced; a first supplier provided along a side surface at least at a position facing a substrate processing region where a plurality of substrates are processed; and a preheating portion provided at a position lower than the substrate processing region, the preheating portion including: a first preheating portion extending in a direction from the gas introduction portion toward a ceiling; and a second preheating portion extending in a direction perpendicular to the direction from the gas introduction portion toward the ceiling, wherein the preheating portion is configured to connect the gas introduction portion with the first supplier by combining the first preheating portion and the second preheating portion, and wherein a cross-sectional shape of the first preheating portion is different from that of the second preheating portion.

According to some embodiments in the present disclosure, it is possible to suppress the decrease in the temperature of the substrate processing region due to the flow of the gas, and as a result, it is possible to reduce the difference in the processing results between substrates arranged in the substrate processing region.

Hereinafter, embodiments according to the technique of the present disclosure will be described with reference to the drawings.

A substrate processing apparatus (also simply referred to as a "processing apparatus") <NUM> according to embodiments of the present disclosure is configured to process a semiconductor wafer. Specifically, for example, the substrate processing apparatus <NUM> is configured to perform a substrate processing such as a film-forming process of forming an oxide film on the semiconductor wafer, a diffusion process on the semiconductor wafer and a CVD process on the semiconductor wafer. According to the embodiments described herein, the semiconductor wafer (hereinafter, also simply referred to as a "wafer") <NUM> serving as a substrate is made of a semiconductor material such as silicon (Si). According to the first embodiment, a FOUP (front opening unified pod) <NUM> is used as a carrier (container) of accommodating and transporting (transferring) a plurality of wafers including the wafer <NUM>.

As shown in <FIG>, the processing apparatus <NUM> according to the first embodiment includes a housing <NUM>. A maintenance space is provided at a lower front portion of a front wall 111a of the housing <NUM>. Front maintenance doors 104a and 104b configured to open and close the maintenance space are provided at the lower front portion of the front wall 111a of the housing <NUM>.

A pod loading/unloading port <NUM> is provided at the front wall 111a of the housing <NUM> so as to communicate with an inside and an outside of the housing <NUM>. The FOUP (hereinafter, also referred to as a "pod") <NUM> may be transferred (loaded) into and transferred (unloaded) out of the housing <NUM> through the pod loading/unloading port <NUM>. A front shutter <NUM> is configured to open and close the pod loading/unloading port <NUM>.

A loading port (also referred to as a "load port shelf) <NUM> is provided in front of the pod loading/unloading port <NUM>. The pod <NUM> is aligned while placed on the load port shelf <NUM>. The pod <NUM> is loaded onto or unloaded from the load port shelf <NUM> by an in-process transfer apparatus (not shown).

An accommodating shelf <NUM> is provided over a substantially center portion in a front-rear direction in the housing <NUM>. The accommodating shelf <NUM> is configured to hold (store) the pod <NUM> and is rotatable. The accommodating shelf <NUM> may hold a plurality of pods (also simply referred to as "pods") including the pod <NUM>. That is, the accommodating shelf <NUM> includes a vertical column <NUM> and a plurality of shelf plates (also simply referred to as "shelf plates") <NUM> provided at the vertical column <NUM>. Each of the shelf plates <NUM> is configured to support pods such as the pod <NUM> placed thereon.

A pod transport device <NUM> serving as a first transport device is provided between the load port shelf <NUM> and the accommodating shelf <NUM> in the housing <NUM>. The pod <NUM> may be elevated or lowered by the pod transport device <NUM> while supported by the pod transport device <NUM>. The pod transport device <NUM> may include a pod elevator 118a and a pod transport mechanism 118b. The pod transport device <NUM> is configured to transport the pod <NUM> among the load port shelf <NUM>, the accommodating shelf <NUM> and a pod opener <NUM> described later by consecutive operations of the pod elevator 118a and the pod transport mechanism 118b.

The substrate processing apparatus <NUM> includes a semiconductor manufacturing apparatus that performs the substrate processing such as the film-forming process of forming the oxide film. A sub-housing <NUM> constituting a housing of the semiconductor manufacturing apparatus is provided below the substantially center portion in the front-rear direction in the housing <NUM> toward a rear end of the substrate processing apparatus <NUM>.

A pair of wafer loading/unloading ports (also referred to as "substrate loading/unloading ports") <NUM> are provided at a front wall 119a of the sub-housing <NUM>. The wafer <NUM> shown in <FIG> may be loaded into or unloaded out of the sub-housing <NUM> through the pair of the wafer loading/unloading ports <NUM>. The pair of the wafer loading/unloading ports <NUM> is arranged vertically in two stages. That is, an upper wafer loading/unloading port and a lower wafer loading/unloading port are provided as the pair of the wafer loading/unloading ports <NUM>. A pair of pod openers including the pod opener <NUM> is provided at the pair of the wafer loading/unloading ports <NUM>, respectively. For example, an upper pod opener and a lower pod opener may be provided as the pair of the pod openers. The upper pod opener and the lower pod opener may be collectively or individually referred to as the "pod opener <NUM>".

The pod opener <NUM> includes a placement table <NUM> where the pod <NUM> is placed thereon and a cap attaching/detaching mechanism <NUM> configured to attach or detach a cap of the pod <NUM>. By detaching or attaching the cap of the pod <NUM> placed on the placement table <NUM> by the pod opener <NUM>, a wafer entrance of the pod <NUM> is opened or closed.

The sub-housing <NUM> defines a transfer chamber <NUM> fluidically isolated from an installation space in which the pod transport device <NUM> or the accommodating shelf <NUM> is provided. A wafer transport mechanism (also referred to as a "substrate transport mechanism") <NUM> is provided in a front region of the transfer chamber <NUM>. The substrate transport mechanism <NUM> is constituted by a wafer transport device (also referred to as a "substrate transport device") 125a and a wafer transport device elevating mechanism (also referred to as a "substrate transport device elevating mechanism") 125b. The substrate transport device 125a is configured to support the wafer <NUM> by tweezers 125c and rotate or move the wafer <NUM> horizontally. The substrate transport device elevating mechanism 125b is configured to elevate or lower the substrate transport device 125a. The substrate transport mechanism <NUM> may load (charge) or unload (discharge) the wafer <NUM> into or out of a boat (also referred to as a "substrate retainer") <NUM> by consecutive operations of the substrate transport device elevating mechanism 125b and the substrate transport device 125a.

As shown in <FIG>, a boat elevator <NUM> serving as an elevating mechanism described later is provided in the transfer chamber <NUM>. The boat elevator <NUM> is configured to elevate or lower the boat <NUM>. A lid <NUM> serving as a cover is provided horizontally at an arm serving as a connecting tool connected to the boat elevator <NUM>. The lid <NUM> is configured to support the boat <NUM> vertically and to close a lower end of a process furnace <NUM> of the substrate processing apparatus <NUM>. The boat <NUM> includes a plurality of support portions (also simply referred to as "support portions") (not shown) serving as a supporting part. The supporting part of the boat <NUM> is configured to support the plurality of the wafers (for example, <NUM> to <NUM> wafers) including the wafer <NUM> in horizontal orientation with their centers aligned concentrically in vertical direction with a predetermined interval therebetween.

The supporting part of the boat <NUM> is made of a material such as quartz (SiO<NUM>), silicon carbide (SiC) and silicon (Si). The material of the supporting part may be selected according to a process temperature. For example, when the process temperature is equal to or less than <NUM>, the supporting part may be made of quartz. When the process temperature is higher than <NUM>, the supporting part may be made of SiC or Si. A fork portion of the supporting part of the boat <NUM> may be of various types depending on process conditions. For example, the fork portion may be short or long, or configured to have a small contact area with the wafer <NUM>.

Next, a pod loading/unloading operation of the substrate processing apparatus <NUM> will be described. As shown in <FIG>, when the pod <NUM> is placed on the load port shelf <NUM>, the pod loading/unloading port <NUM> is opened by the front shutter <NUM>. Then, the pod <NUM> placed on the load port shelf <NUM> is transported (loaded) into the housing <NUM> through the pod loading/unloading port <NUM> by the pod transport device <NUM>.

The pod <NUM> transported into the housing <NUM> is automatically transported to and temporarily stored in a designated shelf plate among the shelf plates <NUM> of the accommodating shelf <NUM> by the pod transport device <NUM>. The pod <NUM> is then transported toward one of the upper and lower pod openers <NUM> from the designated shelf plate and placed on the placement table <NUM>. The pod <NUM> may be directly transported toward the one of the upper and lower pod openers <NUM> and placed on the placement table <NUM>. Simultaneously, the pair of the wafer loading/unloading ports <NUM> are closed by the cap attaching/detaching mechanism <NUM>, and the transfer chamber <NUM> is filled with clean air.

When the wafer entrance of the pod <NUM> placed on the placement table <NUM> is pressed against one of the pair of the wafer loading/unloading ports <NUM> of the front wall 119a of the sub-housing <NUM>, the cap attaching/detaching mechanism <NUM> detaches the cap of the pod <NUM> and the wafer entrance of the pod <NUM> is opened. The wafer <NUM> is then transported out of the pod <NUM> by the tweezers 125c of the substrate transport device 125a, aligned by a notch alignment device (not shown), and transported and charged into the boat <NUM> (wafer charging). The substrate transport device 125a then returns to the pod <NUM> and transports a next wafer among the plurality of the wafers from the pod <NUM> into the boat <NUM>.

While the substrate transport mechanism <NUM> loads the wafer <NUM> from the one of the upper and lower pod openers <NUM> into the boat <NUM>, another pod <NUM> is transported by the pod transport device <NUM> to the other one of the upper and lower pod openers <NUM>, and the cap of the aforementioned another pod <NUM> opened.

When a predetermined number of wafers including the wafer <NUM> are charged into the boat <NUM>, the lower end of the process furnace <NUM> is opened by a furnace opening gate valve <NUM>. Then, the lid <NUM> is elevated by the boat elevator <NUM> and the boat <NUM> supported by the lid <NUM> is loaded into the process furnace <NUM>.

After the boat <NUM> is loaded into the process furnace <NUM>, the plurality of the wafers including the wafer <NUM> are processed in the process furnace <NUM>. After the plurality of the wafers are processed, the boat <NUM> is unloaded by the boat elevator <NUM> serving as an elevating mechanism. The plurality of the wafers and the pod <NUM> are unloaded out of the housing <NUM> in the order reverse to that described above except for an aligning process of the plurality of the wafers by the notch alignment device (not shown).

Subsequently, a configuration of a controller <NUM> serving as a control device will be described with reference to <FIG>. The controller <NUM> may be embodied by a computer that includes a CPU (central processing unit) <NUM>, a memory <NUM> such as a RAM (Random Access Memory) and a ROM (Read Only Memory) serving as a temporary memory device, a hard disk drive (HDD) <NUM> serving as a memory device, and a transmission/reception part <NUM> serving as a communication part. In addition to an instruction part <NUM> including at least the CPU <NUM> and the memory <NUM>, the transmission/reception part <NUM> and the hard disk drive <NUM>, the controller <NUM> may further include a display such as a liquid crystal display and a user interface device <NUM> serving as an operation part including a keyboard and a pointing device such as a mouse. For example, recipe files (not shown) containing recipes defining processing conditions and processing sequences, a control program file (not shown) containing a control program for executing the recipes, a parameter file (not shown) containing parameters for configuring the processing condition and the processing sequence and a display file (not shown) defining an input screen for entering process parameters are stored in the hard disk drive <NUM>.

The transmission/reception part <NUM> of the controller <NUM> may be connected to a switching hub (not shown). The controller <NUM> may transmit and receive data to and from an external computer via a network using the transmission/reception part <NUM>.

For example, the controller <NUM> is electrically connected to components such as a gas flow rate controller (hereinafter, also referred to as a "mass flow controller" or an "MFC") <NUM>, a pressure controller <NUM>, an operation controller <NUM> and a temperature controller <NUM> and sensors (not shown) provided in the housing <NUM> via a communication line through the transmission/reception part <NUM>.

The controller <NUM> according to the first embodiment may be embodied by a general computer system as well as a dedicated system. The controller <NUM> may be embodied by installing the control program (also referred to as a "program") in the general computer system from a recording medium <NUM> such as a USB memory which stores the program. As described above, the program is configured to execute predetermined processes of the recipes.

The method of providing the program is not limited. For example, the program may be provided through the recording medium as described above, a communication line, a communication network or a communication system. In addition, the program may be posted on a bulletin board on the communication network, and may be provided by being superimposed on a carrier wave via the communication network. The program provided as described above may be executed to perform the above-described process under an OS (operating system) just like any other application programs.

As shown in <FIG>, the process furnace <NUM> includes a heater <NUM> serving as a heating apparatus (heating mechanism). The heater <NUM> is of a cylindrical shape, and is vertically installed while being supported by a support plate (also referred to as a "heater base") <NUM>. An upper opening of the heater <NUM> is closed by a lid part <NUM>.

A soaking tube (also referred to as an "outer tube") <NUM> is provided on an inner side of the heater <NUM> so as to be concentric with the heater <NUM>. For example, the soaking tube <NUM> is made of a heat resistant material such as silicon carbide (SiC), and is of a cylindrical shape with a closed upper end and an open lower end.

A reaction tube (also referred to as an "inner tube") <NUM> is provided on an inner side of the soaking tube <NUM> so as to be concentric with the soaking tube <NUM>. The reaction tube <NUM> is made of a heat resistant material such as quartz (SiO<NUM>), and is of a cylindrical shape with a closed upper end and an open lower end. A process chamber <NUM> is provided in a hollow cylindrical portion of the reaction tube <NUM>. The process chamber <NUM> is configured to accommodate vertically arranged wafers including the wafer <NUM> in a horizontal orientation in a multistage manner by the boat <NUM> described later. For example, a space between the reaction tube <NUM> and the soaking tube <NUM> is provided with a clearance of only about <NUM>. Therefore, a pipe with a large diameter cannot be provided in the space between the reaction tube <NUM> and the soaking tube <NUM>.

As shown in <FIG> and <FIG>, a gas introduction portion (hereinafter, also referred to as a "gas inlet") <NUM> of a pipe shape is provided at a lower end side of the reaction tube <NUM>. A process gas is supplied into the reaction tube <NUM> through the gas introduction portion <NUM> from an outside of the reaction tube <NUM>. A plurality of thin pipes (also simply referred to as "thin pipes", for example, three thin pipes according to the first embodiment) <NUM> extend upward from the gas introduction portion <NUM> along an outer peripheral surface of the reaction tube <NUM>. A diameter of each of the thin pipes <NUM> is smaller than a diameter of the gas introduction portion <NUM>, and a cross-section of each of the thin pipes <NUM> is of a circular shape. Upper ends of the thin pipes <NUM> are connected to a preheating portion <NUM> serving as a preheating path arranged on the outer peripheral surface of the reaction tube <NUM>. The thin pipes <NUM> may be considered as a part of the gas introduction portion <NUM>. The thin pipes <NUM> are fixed to the inner tube <NUM> such that each of the thin pipes <NUM> contacts the inner tube <NUM> and the thin pipes <NUM> are adjacent to each other. By providing the thin pipes <NUM>, it is possible to increase a flow rate of a gas such as the process gas supplied into the inner tube <NUM> at one time. The thin pipes <NUM> may be thin enough to fit in the space between the inner tube <NUM> and the outer tube <NUM>. A cross-sectional shape of each of the thin pipes <NUM> is not limited to the circular shape. For example, the cross-section of each of the thin pipes <NUM> may be of a rectangular shape. For example, the diameter of each of the thin pipes <NUM> may range from <NUM> to <NUM>. It is preferable that the diameter of each of the thin pipes <NUM> is <NUM>. In addition, the number of the thin pipes <NUM> may be two or more, for example, three or more.

The preheating portion <NUM> is connected to a plurality of thin pipes (also simply referred to as "thin pipes", for example, three thin pipes according to the first embodiment) <NUM>. Similar to the thin pipes <NUM>, the cross-section of each of the thin pipes <NUM> is of a circular shape. Configurations of the thin pipes <NUM> are essentially same as the thin pipes <NUM>. The thin pipes <NUM> are connected to a nozzle pipe <NUM> via a buffer portion <NUM> provided at a ceiling of the reaction tube <NUM>. The thin pipes <NUM> may also be referred to as a "first supplier" and the nozzle pipe <NUM> may also be referred to as a "second supplier". The process gas introduced through the gas introduction portion <NUM> via a plurality of gas holes (also simply referred to as "gas holes") <NUM> is supplied to the process chamber <NUM>. The gas holes <NUM> serve as a gas supplier, and are provided at the nozzle pipe <NUM> arranged on the outer peripheral surface of the reaction tube <NUM>.

In the present specification, the term "pipe member" refers to a assembly that communicates the gas introduction portion <NUM> to the gas holes <NUM>. That is, components described above such as the thin pipes <NUM>, the preheating portion <NUM>, the thin pipes <NUM>, the buffer portion <NUM>, the nozzle pipe <NUM> and a thin pipe <NUM> described later may be collectively referred to as the "pipe member". However, the pipe member is not limited to the configuration of the first embodiment including the thin pipes <NUM>, the preheating portion <NUM>, the thin pipes <NUM>, the buffer portion <NUM>, the nozzle pipe <NUM> and the thin pipe <NUM>. In addition, as shown in <FIG>, the pipe member is provided outside the reaction tube <NUM>. That is, the pipe member is provided between the reaction tube <NUM> and the heater <NUM>. For example, the diameter of each of the thin pipes <NUM>, the diameter of each of the thin pipes <NUM> and a diameter of thin pipe <NUM> are the same.

According to the first embodiment, a region of a side surface (hereinafter, also referred to as a "side wall") of the reaction tube <NUM> facing the plurality of the wafers including the wafer <NUM> to be processed by the gas in the reaction tube <NUM> may be referred to as a wafer processing region (also referred to as a "substrate processing region") <NUM>, and a region below the wafer processing region <NUM> where the preheating portion <NUM> is disposed may be referred to as a gas preheating region <NUM>. In the gas preheating region <NUM>, the preheating portion <NUM> is provided on the side surface of the reaction tube <NUM> at a position lower than the wafer processing region <NUM> where the plurality of the wafers including the wafer <NUM> are disposed in the process chamber <NUM>. The preheating portion <NUM> extends in a direction detouring from a direction from the gas introduction portion <NUM> toward the ceiling of the reaction tube <NUM>. For example, the preheating portion <NUM> is configured to extend in a direction intersecting with the direction in which the process gas introduced through the gas introduction portion <NUM> flows to the ceiling of the reaction tube <NUM> at a shortest distance. In addition, for example, at least a part of the preheating portion <NUM> is provided to extend in an outer peripheral direction of the reaction tube <NUM>. Hereinafter, the preheating portion <NUM> will be described in detail with reference to the drawings.

As shown in <FIG>, the preheating portion <NUM> includes a plurality of preheating pipes (also simply referred to as "preheating pipes", for example, four preheating pipes according to the first embodiment) <NUM> extending in a circumferential direction of the reaction tube <NUM> over a range of approximately <NUM>°. The preheating pipes <NUM> are arranged in a multistage manner in the vertical direction. End sides of the preheating pipes <NUM> adjacent to each other are alternately connected by a plurality of connecting pipes (also simply referred to as "connecting pipes", for example, three connecting pipes according to the first embodiment) <NUM>. A diameter of each of the connecting pipes <NUM> is smaller than a diameter of each of the preheating pipes <NUM>, and a cross-section of each of the connecting pipes <NUM> is of a circular shape. The preheating portion <NUM> constitutes the preheating path of a rectangular waveform shape (two cycles, two reciprocations) as a whole. According to the first embodiment, the connecting pipes <NUM> correspond to a first preheating portion, and the preheating pipes <NUM> correspond to a second preheating portion. The preheating portion <NUM> is configured by combining the connecting pipes <NUM> and the preheating pipes <NUM>. A starting point and an ending point of the preheating path are located at the preheating pipes <NUM>. the connecting pipes <NUM> is provided between a position of the preheating pipes <NUM> and another position of the preheating pipes <NUM>. The angular range in which the preheating pipes <NUM> are located in the circumferential direction of the reaction tube <NUM> is determined as desired according to a positional relationship between the gas introduction portion <NUM> and the nozzle pipe <NUM>. For example, the angular range in which the preheating pipes <NUM> are located in the circumferential direction of the reaction tube <NUM> is determined by an angular range from an angular position of the gas introduction portion <NUM> to an angular position of the nozzle pipe <NUM> in the circumferential direction. For example, as shown in <FIG>, when the angular position where the gas introduction portion <NUM> is disposed is set to <NUM>° and the angular position where the nozzle pipe <NUM> is disposed is set to N° (N is a positive number equal to or less than <NUM>), the angular range in which the preheating pipes <NUM> are located in the circumferential direction of the reaction tube <NUM> may be set to be greater than <NUM>° and less than N°. In addition, the angular range in which the preheating pipes <NUM> are located in the circumferential direction of the reaction tube <NUM> may be set to be greater than <NUM>° and less than N°. As described above, for example, the angular range in which the preheating pipes <NUM> are located in the circumferential direction of the reaction tube <NUM> may be set to <NUM>°. By providing the preheating pipes <NUM> in the circumferential direction of the reaction tube <NUM>, it is possible to lengthen the preheating path. According to the first embodiment, a configuration of each of the connecting pipes <NUM> is the same as that of each of the thin pipes <NUM> (or the thin pipes <NUM>). According to the first embodiment, cross-sectional areas of flow paths of the connecting pipes <NUM> are set to be essentially the same as cross-sectional areas of flow paths of the thin pipes (for example, three thin pipes) <NUM> or the thin pipes (for example, three thin pipes) <NUM>. In addition, as shown in <FIG> and <FIG>, a temperature sensor <NUM> serving as a temperature detecting device is provided in a space (cylindrical space) between the reaction tube <NUM> and the soaking tube <NUM> (not shown in <FIG> and <FIG>). Preferably, the temperature sensor <NUM> is provided on the space opposite to the preheating pipes <NUM> so as not to be in contact with or close to the preheating pipes <NUM>. That is, when the preheating pipes <NUM> and the temperature sensor <NUM> are close to each other, the temperature sensor <NUM> intended to detect an inner temperature of the reaction tube <NUM> may detect a temperature of the preheating pipes <NUM> instead of the inner temperature of the reaction tube <NUM>. Specifically, the angular range in which the preheating pipes <NUM> are located in the circumferential direction of the reaction tube <NUM> is from the angular position of the gas introduction portion <NUM> to an angular position of the temperature sensor <NUM> in the circumferential direction of the reaction tube.

As shown in <FIG>, since the space between the reaction tube <NUM> and the soaking tube <NUM> is very narrow as described above, a pipe whose vertical cross-section is of a rectangular shape may be used as each of the preheating pipes <NUM> according to the first embodiment. By adjusting the shape of the pipe serving as each of the preheating pipes <NUM> to be same as a vertical cross-sectional shape of the space (also referred to as a "gap") between the reaction tube <NUM> and the soaking tube <NUM>, it is possible to enlarge a cross-sectional shape (that is, a cross-sectional area) of the preheating path. As a result, it is possible to increase the flow rate of the gas such as the process gas passing through the preheating path. In addition, the preheating pipes <NUM> and the connecting pipes <NUM> constituting the preheating portion <NUM> are provided close to or in contact with the outer peripheral surface of the reaction tube <NUM>, and are configured to transfer the heat from the heater <NUM> and the heat from the reaction tube <NUM> to the gas passing through the preheating path in the preheating pipes <NUM> and the connecting pipes <NUM>. According to the first embodiment, the cross-sectional shapes of the thin pipes <NUM> and the connecting pipes <NUM> are different from the cross-sectional shapes of the preheating pipes <NUM> in the gas preheating region <NUM>. Therefore, connecting parts between the thin pipes <NUM> and the preheating pipes <NUM> and connecting parts between the connecting pipes <NUM> and the preheating pipes <NUM> of the preheating portion <NUM> are configured to mix the gas passing through the preheating path. Thus, the gas introduced through the thin pipes <NUM> is supplied into the thin pipes <NUM> via the preheating portion <NUM> while a temperature of the gas at the connecting parts is uniformized. As the number of the connecting parts increases, the effect of maintaining the temperature of the gas by mixing the gas at the connecting parts becomes remarkable. By reducing the length of each of the preheating pipes <NUM> in the vertical direction, it is possible to increase the number of the connecting parts between the connecting pipes <NUM> and the preheating pipes <NUM>. However, by reducing the length of each of the preheating pipes <NUM>, the cross-sectional area of the preheating path of the preheating pipes <NUM> is also reduced. As a result, the flow rate of the gas passing through the preheating path is also reduced. Therefore, according to the first embodiment, the preheating portion <NUM> is configured such that the cross-sectional areas of the flow paths of the thin pipes <NUM> or the cross-sectional area of the preheating path in the connecting pipes <NUM> are equal to or less than the cross-sectional area of the preheating path in the preheating pipes <NUM>, and the gas may pass through the preheating path in the connecting pipes <NUM> and the preheating path in the preheating pipes <NUM> a plurality of times. In addition, as shown in <FIG>, the preheating pipes <NUM> are fixed to the reaction tube <NUM> via a plurality of mounting portions (also simply referred to as "mounting portions") 266A. The mounting portions 266A are provided in the outer peripheral direction of the reaction tube <NUM>. When the preheating pipes <NUM> are brought into contact with and fixed (welded) to the reaction tube <NUM>, (i) the inner temperature of the reaction tube <NUM> (or the process chamber <NUM>) may decrease due to the gas flowing in the preheating pipes <NUM>, (ii) the flow rate of the gas may decrease due to the welding deformation of the preheating pipes <NUM> and (iii) dimensional variations in the clearance and interferences with the components in the reaction tube <NUM> such as the boat <NUM> may occur due to the welding deformation of the reaction tube <NUM>. Therefore, in order to address the risks described above, a structure shown in <FIG> may be used. According to the structure shown in <FIG>, it is possible to reduce welding portions (or welding areas) and contact areas with the reaction tube <NUM> as much as possible. Therefore, it is possible to reduce the risks caused by the welding areas and the contact areas.

The upper ends of the thin pipes <NUM> extending from the gas introduction portion <NUM> are connected to the end of a lowermost preheating pipe among the preheating pipes <NUM> constituting the preheating portion <NUM>, and the lower ends of the thin pipes <NUM> extending upward are connected to the end of a uppermost preheating pipe among the preheating pipes <NUM>.

The buffer portion <NUM> serving as a circular buffer box is provided at an uppermost part of the reaction tube <NUM> (that is, on the ceiling of the reaction tube <NUM>). The upper ends of the thin pipes <NUM> extending from the preheating portion <NUM> are connected to the buffer portion <NUM> on one side in a radial direction of the buffer portion <NUM> such that the gas passing through the preheating portion <NUM> is introduced into the buffer portion <NUM>.

The nozzle pipe <NUM> extending in the vertical direction is provided at the outer peripheral surface of the reaction tube <NUM> opposite to the thin pipes <NUM> and the thin pipes <NUM>. Specifically, the nozzle pipe <NUM> serves as a part of the side wall of the reaction tube <NUM>, and a part of the nozzle pipe <NUM> is provided so as to protrude into the space between the reaction tube <NUM> and the soaking tube <NUM>. An upper end of the nozzle pipe <NUM> is connected to the buffer potion <NUM> via the thin pipe <NUM> with a small diameter so that the gas passing through the buffer portion <NUM> is introduced into the nozzle pipe <NUM>. A horizontal cross-section of the nozzle pipe <NUM> is of a circular shape, and a diameter of the nozzle pipe <NUM> is greater than a diameter of the thin pipe <NUM>. For example, the diameter of the nozzle pipe <NUM> is greater than <NUM>, preferably about <NUM>. The thin pipe <NUM> may be included in a part of the nozzle pipe <NUM>.

The gas holes <NUM> shown in <FIG> configured to eject the gas into the reaction tube <NUM> are provided at the nozzle pipe <NUM> from a lower end to the upper end of the nozzle pipe <NUM> at a predetermined interval (a constant interval) along the longitudinal direction. The gas holes <NUM> are arranged between the plurality of the wafers including the wafer <NUM> at the same interval as the interval between the supporting portions of the boat <NUM> configured to support the plurality of the wafers. The gas holes <NUM> are provided at the nozzle pipe <NUM> so as to eject the gas between the plurality of the wafers including the wafer <NUM>.

As shown in <FIG>, a gas exhaust portion (also referred to as an "exhaust portion" or a "gas outlet") <NUM> of a pipe shape is provided at the lower side of the reaction tube <NUM> opposite to the nozzle pipe <NUM>. The gas exhaust portion <NUM> is configured to discharge (exhaust) an inner atmosphere of the reaction tube <NUM> to the outside of the reaction tube <NUM>. As shown in <FIG>, the gas exhaust portion <NUM> is provided closer to the gas introduction portion <NUM> than to the nozzle pipe <NUM>. Specifically, the gas exhaust portion <NUM> is located at a position of the reaction tube <NUM> opposite to the other position where the nozzle pipe <NUM> is located. An angular position of the gas exhaust portion <NUM> is between the angular position of the gas introduction portion <NUM> and the angular position of the nozzle pipe <NUM>. The gas exhaust portion <NUM> is provided lower than the preheating pipes <NUM>.

As shown in <FIG>, a process gas supply source (not shown), a carrier gas supply source (not shown) and an inert gas supply source (not shown) are connected to an upstream side of the gas introduction portion <NUM> via the MFC (that is, the gas flow rate controller) <NUM>. The MFC <NUM> is configured to control the flow rate of the gas supplied into the process chamber <NUM> to a desired flow rate at a desired timing. A gas supply system according to the first embodiment is constituted by at least the process gas supply source, the carrier gas supply source, the inert gas supply source and the MFC <NUM>.

A sequencer (not shown) is configured to control the supply or the stop of the supply of the gas by opening and closing a valve (not shown). The controller <NUM> is configured to control the MFC <NUM> and the sequencer to adjust the flow rate of the gas supplied into the process chamber <NUM> to the desired flow rate at the desired timing.

<FIG> schematically illustrates the process furnace <NUM> when the boat <NUM> is loaded into the reaction tube <NUM>. In <FIG>, only some of the plurality of the wafers including the wafer <NUM> are shown for simplification. Horizontal arrows in <FIG> indicate flows (directions) of the process gas. In a heat insulating region of the boat <NUM> (that is, a region where a plurality of heat insulating plates (also simply referred to as "heat insulating plates") 218A of a heat insulating cylinder <NUM> described later is accommodated), a distance (pitch) between adjacent heat insulating plates among the heat insulating plates 218A is about ten millimeters, and the distances between the gas holes <NUM> of the nozzle pipe <NUM> (not shown in <FIG>) are also set to be equal to the pitch of the heat insulating plates 218A. A lowermost gas hole among the gas holes <NUM> (not shown in <FIG>) is provided at a position facing the gas exhaust portion <NUM> shown in <FIG>.

As described above, it is possible to supply the gas to the lower end of the boat <NUM> (the position facing the gas exhaust portion <NUM>) by providing the gas holes <NUM> at the lower end of the boat <NUM>. Therefore, it is possible to eliminate the gas stagnation at the lower end of the boat <NUM>. In particular, even in the heat insulating region, by supplying the gas into the process chamber <NUM> through the gas holes <NUM>, it is possible to form the flow of the gas on each of the surface of the heat insulating plates 218A. In this manner, it is possible to form the flow of the gas the same as the gas in the wafer processing region <NUM>. Therefore, it is possible to suppress the particles due to the gas stagnation at a lower end of the wafer processing region <NUM>.

The gas is continuously heated by the heat from the reaction tube <NUM> and the heat from the heater <NUM> while the gas temporarily stagnates in the buffer portion <NUM> described above. Then, the gas sufficiently heated by the heat is ejected through the gas holes <NUM> of the nozzle pipe <NUM> and supplied into the process chamber <NUM>. As a result, it is possible to reduce temperature differences between the gas supplied into the process chamber <NUM> and components constituting the process chamber <NUM> such as a SiC component, a quartz component and the wafer <NUM>. Therefore, it is possible to reduce the particles due to the temperature differences.

As shown in <FIG>, a support body <NUM> serving as a base flange capable of hermetically sealing a lower end opening of the reaction tube <NUM> and the lid <NUM> are provided at a lower end of the reaction tube <NUM>. For example, the lid <NUM> is made of a metal such as stainless steel and is of a disk shape. For example, the support body <NUM> provided on the lid <NUM> is made of quartz and is of a disk shape. An O-ring <NUM> serving as a sealing part in contact with the lower end of the reaction tube <NUM> is provided on an upper surface of the support body <NUM>.

A rotating mechanism <NUM> configured to rotate the boat <NUM> is provided on the lid <NUM> opposite to the process chamber <NUM>. A rotating shaft <NUM> of the rotating mechanism <NUM> is connected to the heat insulating cylinder <NUM> and the boat <NUM> through the lid <NUM> and the support body <NUM>. The rotating mechanism <NUM> rotates the heat insulating cylinder <NUM> and the boat <NUM> to rotate the plurality of the wafers including the wafer <NUM>.

The lid <NUM> is elevated or lowered in the vertical direction by the boat elevator <NUM> vertically installed outside the reaction tube <NUM> so as to load the boat <NUM> into or unload the boat <NUM> out of the process chamber <NUM>. The operation controller <NUM> is electrically connected to the rotating mechanism <NUM> and the boat elevator <NUM>. The operation controller <NUM> may control the rotating mechanism <NUM> and the boat elevator <NUM> such that the rotating mechanism <NUM> and the boat elevator <NUM> perform a desired operation at a desired timing.

The boat <NUM> is made of a heat resistant material such as quartz and silicon carbide (SiC), and is configured to support the plurality of wafers including the wafer <NUM> vertically arranged in a horizontal orientation in a multistage manner with their centers aligned. The heat insulating cylinder <NUM> serving as a heat insulating member is provided below the boat <NUM> to support the boat <NUM>. For example, the heat insulating cylinder <NUM> is made of a heat resistant material such as quartz and silicon carbide and is of a cylindrical shape. The heat insulating cylinder <NUM> is configured to suppress the heat emitted from the heater <NUM> from being transmitted to the lower end portion of the reaction tube <NUM>.

The temperature controller <NUM> is electrically connected to the heater <NUM> and the temperature sensor <NUM>. The temperature controller <NUM> is configured to adjust a state of electric conduction to the heater <NUM> based on the temperature detected by the temperature sensor <NUM> such that an inner temperature of the process chamber <NUM> reaches and is maintained at a desired temperature at a desired timing.

An exhaust pipe <NUM> is connected to the gas exhaust portion <NUM>. A pressure adjusting device <NUM> including at least an APC (Automatic Pressure Controller) valve and an exhaust device (not shown) are connected to a downstream side of the exhaust pipe <NUM>. An exhaust system is constituted by the components described above such as the exhaust pipe <NUM>, the pressure adjusting device and the exhaust device. The pressure controller <NUM> is electrically connected to the pressure adjusting device <NUM> and the exhaust device. The pressure controller <NUM> may be configured to control the exhaust system such that an inner pressure of the process chamber <NUM> reaches and is maintained at a predetermined pressure.

Subsequently, a method of performing a substrate processing such as an oxidation process and a diffusion process (particularly, the substrate processing such as a PYRO oxidation process, a DRY oxidation process and an annealing process) on the wafer <NUM>, which is a part of manufacturing processes of a semiconductor device, will be described. The substrate processing may be performed using the process furnace <NUM> of the substrate processing apparatus <NUM>. In the following description, the operations of the components constituting the substrate processing apparatus <NUM> are controlled by the controller <NUM>.

After the plurality of wafers including the wafer <NUM> are transported (charged) into the boat <NUM> (wafer charging), the boat <NUM> charged with the plurality of wafers is elevated by the boat elevator <NUM> and transferred (loaded) into the process chamber <NUM> (boat loading). With the boat <NUM> loaded, the lid <NUM> seals the lower end of the reaction tube <NUM> via the support body <NUM> and the O-ring <NUM>.

The process chamber <NUM> is heated by the heater <NUM> such that the inner temperature of the process chamber <NUM> reaches and is maintained at the desired temperature. The electric conduction state to the heater <NUM> is feedback-controlled based on the temperature detected by the temperature sensor <NUM> such that the inner temperature of the process chamber <NUM> has a predetermined temperature distribution. Subsequently, the rotating mechanism <NUM> rotates the heat insulating cylinder <NUM> and the boat <NUM> to rotate the plurality of wafers including the wafer <NUM>.

Subsequently, the gas supplied through the process gas supply source (not shown) and the carrier gas supply source (not shown) and adjusted (controlled) to the desired flow rate by the MFC <NUM> is introduced into the gas introduction portion <NUM>. The gas introduced into the gas introduction portion <NUM> at the lower side of the reaction tube <NUM> flows through the thin pipes <NUM>, and is introduced into the nozzle pipe <NUM> via the preheating portion <NUM>, the thin pipes <NUM> and the buffer portion <NUM>. Then, the gas is introduced into the process chamber <NUM> through the gas holes <NUM>.

The gas introduced into the gas introduction portion <NUM> is preheated at the preheating portion <NUM> by the heat from the heater <NUM> and the heat from the reaction tube <NUM>, and passes through the thin pipes <NUM> in the wafer processing region <NUM> after the temperature of the gas is sufficiently increased. Therefore, it is possible to suppress the decrease in the temperature of the wafer processing region <NUM>. As a result, it is possible to uniformize the temperature of the wafer processing region <NUM> facing the plurality of the wafers including the wafer <NUM> in the reaction tube <NUM>.

When the gas introduced into the gas introduction portion <NUM> passes through the wafer processing region <NUM> without preheating, the gas with a low temperature may pass through the thin pipes <NUM>, the temperature of a portion where the thin pipes <NUM> are arranged may decrease and the temperature of the reaction tube <NUM> may become uneven (nonuniform). As a result, a temperature uniformity of the plurality of the wafers including the wafer <NUM> may be adversely affected.

The gas heated by passing through the preheating portion <NUM> is ejected into the process chamber <NUM> through the gas holes <NUM> provided in the nozzle pipe <NUM> via the buffer portion <NUM>. The gas ejected through the gas holes <NUM> comes into contact with the surface of the wafer <NUM> when passing through the process chamber <NUM>. As a result, the process such as the oxidation process and the diffusion process is performed onto the wafer <NUM>. As the boat <NUM> is rotated, the wafer <NUM> is also rotated such that the gas contacts the entire surface of the wafer <NUM>.

Since the temperature of the wafer processing region <NUM> facing the plurality of wafers including the wafer <NUM> is uniformized, it is possible to uniformly heat the plurality of wafers including the wafer <NUM>.

In addition, by exhausting the process chamber <NUM> by an ejector (not shown) provided at a downstream side of the gas exhaust portion <NUM>, the gas with a uniform flow rate is supplied through each of the gas holes <NUM> to the process chamber <NUM> at a predetermined flow rate. Thereby, it is possible to quickly exhaust an outgas during a heat treatment process to the exhaust system.

When a process using water vapor is performed onto the wafer <NUM>, the flow rate of the gas is adjusted to a desired flow rate by the MFC <NUM>, and the gas with the flow rate thereof adjusted is then supplied to a water vapor generator (not shown). Then, the gas containing the water vapor (H<NUM>O) generated by the water vapor generator is supplied into the process chamber <NUM>.

After a predetermined processing time has elapsed, an inert gas is supplied through inert gas supply source to replace an inner atmosphere of the process chamber <NUM> with an inert gas, and the inner pressure of the process chamber <NUM> is returned to normal pressure.

Thereafter, the lid <NUM> is lowered by the boat elevator <NUM> and the lower end of the reaction tube <NUM> is opened. Then, the processed wafers including the wafer <NUM> charged in the boat <NUM> are unloaded out of the reaction tube <NUM> through the lower end of the reaction tube <NUM> (boat unloading). The processed wafers <NUM> are then discharged from the boat <NUM> (wafer discharging).

As described above, in the substrate processing apparatus <NUM> according to the first embodiment, the gas passing through the thin pipes <NUM> provided at the wafer processing region <NUM> is sufficiently preheated at the preheating portion <NUM>, and the influence of the temperature of the gas passing through the thin pipes <NUM> on the wafer processing region <NUM> is suppressed. As a result, since the temperature of the wafer processing region <NUM> facing the plurality of wafers including the wafer <NUM> is uniformized, it is possible to suppress the processing failure of the wafer <NUM> due to the nonuniform temperature of the wafer processing region <NUM>.

Hereinafter, a substrate processing apparatus <NUM> according to a second embodiment will be described with reference to <FIG>. The same components as those of the first embodiment will be denoted by like reference numerals, and detailed description thereof will be omitted.

As shown in <FIG>, in the substrate processing apparatus <NUM> according to the second embodiment, an upper heater <NUM> of a cylindrical shape is provided above the heater <NUM>. The upper heater <NUM> is provided so as to face the buffer portion <NUM> at a radially outer side of the buffer portion <NUM>. In addition, the upper heater <NUM> is provided so as not to face the plurality of the wafers including the wafer <NUM> to be processed by the gas in the reaction tube <NUM> at radially outer sides of the plurality of the wafers. That is, the upper heater <NUM> is provided above the wafer processing region <NUM>. A ceiling heater <NUM> of a plate shape is provided above the soaking tube <NUM>. It is possible to adjust (set) temperatures of the upper heater <NUM> and the ceiling heater <NUM> differently by the controller <NUM>.

In the substrate processing apparatus <NUM> according to the second embodiment, it is possible to heat the gas stagnated in the buffer part <NUM> by at least one among the upper heater <NUM> and the ceiling heater <NUM>. Therefore, it is possible to process the wafer <NUM> by supplying the gas with a higher temperature than that of the first embodiment into the process chamber <NUM> of the reaction tube <NUM>. Accordingly, the gas such as the process gas can be supplied into the process chamber <NUM> while reducing a temperature difference between the process gas and components constituting the process chamber <NUM>. As a result, it is possible to reduce the particles due to the temperature difference. Other operations and effects of the second embodiment are the same as those of the first embodiment.

Hereinafter, a substrate processing apparatus <NUM> according to a third embodiment will be described with reference to <FIG>. The same components as those of the first embodiment will be denoted by like reference numerals, and detailed description thereof will be omitted.

As shown in <FIG>, in the substrate processing apparatus <NUM> according to the third embodiment, the preheating pipes <NUM> of the preheating portion <NUM> of the first embodiment is replaced with a plurality of preheating pipes (also simply referred to as "preheating pipes", for example, three preheating pipes whose cross-sections are of a circular shape according to the third embodiment) <NUM>. As described above, the cross-section of each of the preheating pipes <NUM> is of a rectangular shape. The preheating pipes <NUM> may also be referred to as a "main preheating portion". A plurality of joints (also simply referred to as "joints") <NUM> are configured to connect the preheating pipes <NUM> and the connecting pipes <NUM>, the preheating pipes <NUM> and the thin pipes <NUM>, and the preheating pipes <NUM> and the thin pipes <NUM>, respectively. The preheating pipes <NUM> and the joints <NUM> correspond to a second preheating portion according to the third embodiment. A pipe whose vertical cross-section is of a rectangular shape is used as each of the connecting pipes <NUM> according to the third embodiment. Thus, a cross-sectional shape of each of the connecting pipes <NUM> of the third embodiment is different from those of the connecting pipes <NUM> of the first embodiment, the preheating pipes <NUM>, the thin pipes <NUM> and the thin pipes <NUM>, whose cross-sections are of a circular shape. According to the third embodiment, a thin pipe is used as each of the preheating pipes <NUM>. However, since a set of three thin pipes are used as the preheating pipes <NUM>, it is possible to increase a cross-sectional area of the flow path of the preheating pipes <NUM>. Therefore, it is possible to sufficiently preheat the gas similarly to the preheating pipes <NUM> of the first embodiment. Other operations and effects of the third embodiment are the same as those of the first and second embodiments.

The test is performed using two types of reaction tubes according to comparative examples (that is, a first comparative example and a second comparative example) and three types of reaction tubes according to examples (that is, a first example, a second example and a third example) of the embodiments in which the preheating path described above is provided. Test results obtained by comparing and verifying the reaction tubes according to the first comparative example, the second comparative example, the first example, the second example and the third example will be described below. In the following description and the drawings illustrating the comparative examples and the examples, the same components as those of the embodiments described above will be denoted by like reference numerals, and detailed description thereof will be omitted.

The nozzle pipe <NUM> and an internal structure of the reaction tube <NUM> according to each of the comparative examples and the examples are the same. However, according to each of the comparative examples and the examples, a configuration of a gas path from the gas introduction portion <NUM> to the nozzle pipe <NUM> is different. Hereinafter, differences between the gas paths according to the comparative examples and the examples will be described.

As shown in <FIG> and <FIG>, according to the first comparative example (indicated by "<NUM>st CE" in <FIG>), three thin pipes <NUM> extending upward on the outer surface of the reaction tube <NUM> from the gas introduction portion <NUM> are directly connected to the nozzle pipe <NUM> across the uppermost side of the reaction tube <NUM>. For example, an inner diameter Φ of each of the three thin pipes <NUM> is <NUM>. According to the first comparative example, no preheating path is provided.

As shown in <FIG>, according to the second comparative example (indicated by "<NUM>nd CE" in <FIG>), a thin pipe <NUM> extending upward on the outer surface of the reaction tube <NUM> from the gas introduction portion <NUM> is directly connected to the nozzle pipe <NUM> across the uppermost side of the reaction tube <NUM>. For example, an inner diameter Φ of the thin pipe <NUM> is <NUM>. According to the second comparative example, no preheating path is provided.

As shown in <FIG>, according to the first example of the embodiments (indicated by "<NUM>st EE" in <FIG>), the thin pipes (three thin pipes) <NUM> extend upward on the outer surface of the reaction tube <NUM> from the gas introduction portion <NUM> to the preheating portion <NUM>. For example, an inner diameter Φ of each of the three thin pipes <NUM> is <NUM>. The thin pipes (three thin pipes) <NUM> extending upward from the preheating portion <NUM> are connected to the nozzle pipe <NUM> across the uppermost side of the reaction tube <NUM>. According to the first example, the preheating portion <NUM> is configured by disposing the three thin pipes <NUM> serving as preheating pipes in the circumferential direction of the reaction tube <NUM> over a range of <NUM>° and reciprocating the preheating path once.

As shown in <FIG>, according to the second example of the embodiments (indicated by "<NUM>nd EE" in <FIG>), the thin pipes (three thin pipes) <NUM> extend upward on the outer surface of the reaction tube <NUM> from the gas introduction portion <NUM> to the preheating portion <NUM>. For example, the inner diameter Φ of each of the three thin pipes <NUM> is <NUM>. The thin pipes (three thin pipes) <NUM> extending upward from the preheating portion <NUM> are connected to the nozzle pipe <NUM> across the uppermost side of the reaction tube <NUM>. According to the second example, the preheating portion <NUM> is configured by disposing the three thin pipes <NUM> serving as the preheating pipes in the circumferential direction of the reaction tube <NUM> over a range of <NUM>° and reciprocating the preheating path twice.

As shown in <FIG>, according to the third example of the embodiments (indicated by "<NUM>rd EE" in <FIG>), the thin pipes (three thin pipes) <NUM> extend upward on the outer surface of the reaction tube <NUM> from the gas introduction portion <NUM> to the preheating portion <NUM>. For example, the inner diameter Φ of each of the three thin pipes <NUM> is <NUM>. The thin pipes (three thin pipes) <NUM> extending upward from the preheating portion <NUM> are connected to the nozzle pipe <NUM> across the uppermost side of the reaction tube <NUM>. According to the third example, the preheating portion <NUM> is configured by disposing a rectangular pipe <NUM> in the circumferential direction of the reaction tube <NUM> over a range of <NUM>° and reciprocating the preheating path twice. A cross-section of the rectangular pipe <NUM> is of a rectangular shape with dimensions of <NUM> × <NUM>.

<FIG> schematically illustrates the test results in which temperatures of inner walls of the reaction tubes (that is, temperature distributions) according to the first comparative example, the second comparative example, the first example, the second example and the third example are represented as differences in concentration. In <FIG>, the higher the concentration (the darker the concentration), the higher the temperature. As shown in <FIG>, according to the first comparative example and the second comparative example, temperature at position of the reaction tube <NUM> where the thin pipes <NUM> extending upward from the gas introduction portion <NUM> or the thin pipe <NUM> extending upward is provided are lower than temperature at position of the reaction tube <NUM> where the thin pipes <NUM> or the thin pipe <NUM> is not provided. That is, according to the first comparative example and the second comparative example, the temperature of the reaction tube <NUM> is uneven (nonuniform). As shown in <FIG>, according to the first example, the second example and the third example, it is possible to suppress the unevenness (nonuniformity) in the temperature of the reaction tube <NUM> as compared with the first comparative example and the second comparative example.

The preheating path of the preheating portion <NUM> of each of the examples (that is, the first example, the second example and the third example) is longer than that of each of the comparative examples (that is, the first comparative example and the second comparative example). Therefore, according to the examples, the gas is preheated more efficiently and the influence of the gas passing through the thin pipes <NUM> is reduced. Therefore, according to the examples, it is possible to suppress the unevenness (nonuniformity) in the temperature of the reaction tube <NUM> as compared with the comparative examples. The preheating path of the preheating portion <NUM> of each of the second example and the third example is longer than that of the first example. Therefore, according to the second example and the third example, the gas is preheated more efficiently and the influence of the gas passing through the thin pipes <NUM> is more reduced. Therefore, according to the second example and the third example, it is possible to suppress the unevenness (nonuniformity) in the temperature of the reaction tube <NUM> as compared with the first example. The cross-sectional area (or dimensions) of the preheating path of the preheating portion <NUM> of the third example is greater than that the cross-sectional area (or inner diameter) of the preheating path of the preheating portion <NUM> of the second example. Therefore, according to the third example, the gas is preheated more efficiently and the influence of the gas passing through the thin pipes <NUM> is more reduced. Therefore, according to the third example, it is possible to suppress the unevenness (nonuniformity) in the temperature of the reaction tube <NUM> as compared with the second example. In particular, according to the third embodiment, since the cross-sectional area (or dimensions) of the preheating path of the preheating portion <NUM> is large and the preheating path is long, an area where the gas is applied to the heat in the pre-heating portion <NUM> and a contact time during the gas being applied to the heat in the pre-heating portion <NUM> are increased as compared with the comparative examples, the first example and the second example. Therefore, the temperature of the gas is sufficiently increased before flowing into the thin pipes <NUM>. As a result, it is possible to substantially eliminate the temperature unevenness (nonuniformity) in the wafer processing region <NUM>.

A graph on a left side of <FIG> schematically illustrates the temperatures (temperature distributions) of the inner walls of the reaction tubes according to the comparative examples and the examples at a side (indicated by "INLET SIDE") in the vertical direction where the gas introduction portion <NUM> is provided. A graph on a center side of <FIG> schematically illustrates the temperatures (temperature distributions) of the inner walls of the reaction tubes according to the comparative examples and the examples at a side (indicated by "OUTLET SIDE") in the vertical direction where the gas exhaust portion <NUM> is provided. The vertical axes of the graphs shown on the left side and the center side of <FIG> represent a height dimension (in unit of mm) with the lower end of the wafer processing region <NUM> as a reference ("<NUM>"), and the horizontal axes of the graphs shown on the left side and the center side of <FIG> represent the temperature (in unit of °C) of the inner wall of the reaction tube <NUM>. The vertical axis of a graph on a right side of <FIG> represents the height dimension (in unit of mm) with the lower end of the wafer processing region <NUM> as the reference ("<NUM>"), and the horizontal axis of the graph on the right side of <FIG> represents the temperature difference between the temperature of the "INLET SIDE" and the temperature of the "OUTLET SIDE". As shown in the graph on the right side of <FIG>, it is confirmed that the temperature difference in the wafer processing region <NUM> according to each of the examples is small as compared with that of each of the comparative examples. That is, the temperature unevenness (nonuniformity) in the wafer processing region <NUM> according to each of the examples is small as compared with that of each of the comparative examples. As described above, according to the configuration of each of the examples to which the embodiments of the technique is applied, it is possible to suppress the temperature unevenness (nonuniformity) in the wafer processing region <NUM> of the reaction tube <NUM>. As a result, it is possible to uniformly process the plurality of wafers including the wafer <NUM> accommodated in the boat <NUM>.

According to the embodiments described above, the buffer portion <NUM> is provided at the uppermost side of the reaction tube <NUM> in addition to the preheating portion <NUM>, and the gas temporarily stagnated in the buffer portion <NUM> is heated. However, when the temperature of the gas ejected through the nozzle pipe <NUM> into the process chamber <NUM> is sufficiently high (that is, the temperature required for processing the wafer <NUM> is reached), as shown in <FIG>, the buffer portion <NUM> may be omitted, and ends of the thin pipes <NUM> may be directly connected to the nozzle pipe <NUM>. That is, according to another embodiment, the pipe member may include the thin pipes <NUM>, the preheating portion <NUM>, the thin pipes <NUM> and the nozzle pipe <NUM>.

According to another embodiment described above, there is provided a substrate processing apparatus including: the reaction tube <NUM> provided therein with the process chamber <NUM> where the wafer <NUM> is processed; the gas introduction portion <NUM> provided at the lower end of the reaction tube <NUM> and through which the process gas is introduced into the reaction tube <NUM>; the pipe member provided between the reaction tube <NUM> and the heater <NUM>, extending in the direction from the gas introduction portion <NUM> to the nozzle pipe <NUM> across the ceiling of the reaction tube <NUM>, and configured to communicate the gas introduction portion <NUM> with the nozzle pipe <NUM>; and the gas exhaust portion <NUM> configure to exhaust the process gas from the process chamber <NUM>. The nozzle pipe <NUM> is provided on the side surface of the reaction tube <NUM>, and the gas holes <NUM> are provided at the nozzle pipe <NUM>. The gas exhaust portion <NUM> is provided at the lower end of the reaction tube <NUM> opposite to the nozzle pipe <NUM>. The pipe member includes the preheating path (that is, the preheating portion <NUM>). The preheating portion <NUM> is provided on the side surface of the reaction tube <NUM> at the position lower than the substrate processing region where the plurality of the wafers including the wafer <NUM> are disposed in the process chamber <NUM>, and extends in a direction intersecting with a direction of a shortest distance connecting the gas introduction portion <NUM> and the ceiling of the reaction tube <NUM>. Operations and effects of another embodiment described above are the same as at least those of the first embodiment. According to another embodiment described above, at least one among the upper heater <NUM> and the ceiling heater <NUM> of the second embodiment may be further provided. In such a case, the operations and the effects of another embodiment described above are the same as those of the second embodiment.

According to another embodiment described above, the temperature of the gas ejected through the nozzle pipe <NUM> into the process chamber <NUM> is sufficiently high (that is, the temperature required for processing the wafer <NUM> is reached). However, by providing the preheating portion <NUM>, the temperature of the gas ejected into the process chamber <NUM> may be sufficiently increased and the temperature of the gas in the flow path up to the gas holes <NUM> may be sufficiently increased. Therefore, in such a case, as shown in <FIG>, the buffer portion <NUM> and the nozzle pipe <NUM> may be omitted, and a simple configuration in which the thin pipes <NUM>, the thin pipes <NUM> and the preheating portion <NUM> are provided on the outer peripheral surface of the reaction tube <NUM> and the gas holes <NUM> are provided at the thin pipes <NUM> at the ceiling of the reaction tube <NUM> may be used. That is, according to still another embodiment, the pipe member may include the thin pipes <NUM>, the preheating portion <NUM> and the thin pipes <NUM>.

According to still another embodiment described above, there is provided a substrate processing apparatus including: the reaction tube <NUM> provided therein with the process chamber <NUM> where the wafer <NUM> is processed; the gas introduction portion <NUM> provided at the lower end of the reaction tube <NUM> and through which the process gas is introduced into the reaction tube <NUM>; the pipe member provided between the reaction tube <NUM> and the heater <NUM> and configured to communicate the gas introduction portion <NUM> with the gas holes <NUM>; and the gas exhaust portion <NUM> configure to exhaust the process gas from the process chamber <NUM>. The gas holes <NUM> are provided at the ceiling of the reaction tube <NUM>, and are configured to supply the process gas into the process chamber <NUM>. The pipe member includes the preheating path (that is, the preheating portion <NUM>). The preheating portion <NUM> is provided on the side surface of the reaction tube <NUM> at the position lower than the substrate processing region where the plurality of the wafers including the wafer <NUM> are disposed in the process chamber <NUM>, and extends in a direction intersecting with a direction of connecting the gas introduction portion <NUM> and the ceiling of the reaction tube <NUM> by the shortest distance. Operations and effects of still another embodiment described above are the same as those of the first embodiment.

According to still another embodiment described above, the buffer portion <NUM> provided at the ceiling of the reaction tube <NUM> to temporarily store the process gas may be further provided. The buffer portion <NUM> is configured to communicate the pipe member to the process chamber <NUM>, and the gas holes <NUM> configured to supply the process gas into the process chamber <NUM> are provided at the buffer portion <NUM>. In such a case, even when the process gas stagnates in the buffer portion <NUM> by providing the buffer portion <NUM>, the process gas is heated by the heater <NUM>. Therefore, it is possible to heat the process gas sufficiently. According to still another embodiment described above, at least one among the upper heater <NUM> and the ceiling heater <NUM> of the second embodiment may be further provided. In such a case, the operations and the effects of still another embodiment described above are the same as those of the second embodiment.

While the technique is described in detail by way of the above-described embodiments, the above-described technique is not limited thereto. The above-described technique may be modified in various ways without departing from the gist thereof.

For example, the above-described embodiments are described by way of an example in which the flow path of the gas (that is, the preheating path constituted by components such as the preheating pipes <NUM> and the connecting pipes <NUM>) is of the rectangular waveform shape when viewed from the reaction tube <NUM>. However, the above-described technique is not limited thereto. For example, instead of the rectangular waveform shape, the preheating path may be of a so-called zigzag shape such as a sine curve shape and a triangular wave shape. In such a case, a specific shape of the zigzag shape and a direction in which the zigzag shape extends are not particularly limited.

That is, the preheating portion <NUM> may be constituted by: a first portion on the side surface of the reaction tube <NUM> extending in the direction (for example, the circumferential direction of the reaction tube <NUM>) intersecting with the direction (for example, the vertical direction with respect to the reaction tube <NUM>) of connecting the gas introduction portion <NUM> and the buffer portion <NUM> by the shortest distance in the flow path of the gas; and a second portion such as pipes bypassing in the circumferential direction rather than connecting the gas introduction portion <NUM> to the buffer portion <NUM> with the shortest distance so as to lengthen the preheating path. Thereby, it is possible to sufficiently preheat the gas.

Although not shown in the drawings, at the preheating portion <NUM>, the preheating path (that is, the pipes) through which the gas passes may be provided in a spiral shape on the outer peripheral surface of the reaction tube <NUM>. In such a case, it is possible to lengthen the preheating path through which the gas flows. Thereby, it is possible to sufficiently preheat the gas.

For example, the above-described embodiments are described by way of an example in which the wafer serving as a substrate is processed. However, the above-described technique is not limited thereto. For example, the above-described technique may also be applied to substrate processing apparatuses configured to process a glass substrate of a liquid crystal panel or a substrate such as a magnetic disk and an optical disk.

The invention may also be summarized as follows: Described herein is a technique capable of reducing a difference in processing results between substrates. According to one aspect of the technique, there is provided a reaction tube having a process chamber; a gas introduction portion provided at a lower end; a first supplier provided along a side surface to face a substrate processing region; and a preheating portion provided lower than the substrate processing region, the preheating portion including: a first preheating portion extending in a direction from the gas introduction portion toward a ceiling; and a second preheating portion extending in a direction perpendicular to the above direction, wherein the preheating portion connects the gas introduction portion with the first supplier by combining the first preheating portion and the second preheating portion.

Claim 1:
A reaction tube (<NUM>) provided therein with a process chamber (<NUM>) and heated by a heater provided therearound, the reaction tube (<NUM>) comprising:
a gas introduction portion (<NUM>) provided at a lower side and through which a process gas is introduced;
a first supplier (<NUM>) provided along a side surface at least at a position facing a substrate processing region (<NUM>) where a plurality of substrates (<NUM>) is processed; and
a preheating portion (<NUM>) provided at a position lower than the substrate processing region (<NUM>), the preheating portion (<NUM>) comprising:
a first preheating portion (<NUM>) extending in a direction from the gas introduction portion (<NUM>) toward a ceiling; and
a second preheating portion (<NUM>) extending in a direction perpendicular to the direction from the gas introduction portion (<NUM>) toward the ceiling,
wherein the preheating portion (<NUM>) is configured to connect the gas introduction portion (<NUM>) with the first supplier (<NUM>) by combining the first preheating portion (<NUM>) and the second preheating portion (<NUM>),
and wherein a cross-sectional shape of the first preheating portion (<NUM>) is different from that of the second preheating portion (<NUM>).