阅读说明：本技术 基板处理装置及半导体器件的制造方法 (Substrate processing apparatus and method for manufacturing semiconductor device ) 是由 西堂周平 佐佐木隆史 吉田秀成 于 2018-09-25 设计创作，主要内容包括：本发明提供一种能够缓和将多张晶片并排处理时的多个晶片的面间不均匀性(负载效应)的基板处理装置,基板处理装置构成为,包括：基板保持件,其按照规定的间隔排列保持多个基板；收容基板保持件的反应管,其具备使上端闭塞的顶板,并在下方具有能够使基板保持件出入的开口；炉体,其包围该反应管的上方及侧方；盖,其直接或间接保持基板保持件,并封堵开口；以及气体供给机构,其向在反应管内保持于基板保持件的多个基板各自的表侧的面提供与表侧的面平行的气体流动,基板保持件构成为,保持形成有集成电路图案的产品基板或监控基板和在表侧的面形成有Si熔射层的虚设基板,其中,所述虚设基板位于隔着该产品基板或监控基板的两侧的位置。(The present invention provides a substrate processing apparatus capable of alleviating surface unevenness (load effect) of a plurality of wafers when the plurality of wafers are processed side by side, the substrate processing apparatus comprising: a substrate holder configured to hold a plurality of substrates in a row at a predetermined interval; a reaction tube for accommodating the substrate holder, which has a top plate with a closed upper end and an opening for allowing the substrate holder to move in and out at a lower part; a furnace body surrounding the upper and lateral sides of the reaction tube; a cover that directly or indirectly holds the substrate holder and closes the opening; and a gas supply mechanism for supplying a gas flow parallel to the front surface of each of the plurality of substrates held in the substrate holder in the reaction tube, wherein the substrate holder holds a product substrate or a monitor substrate on which an integrated circuit pattern is formed and a dummy substrate on which an Si thermal sprayed layer is formed on the front surface, and the dummy substrate is positioned on both sides of the product substrate or the monitor substrate.)

1. A substrate processing apparatus, comprising:

a substrate holder configured to hold a plurality of substrates in a row at a predetermined interval;

a reaction tube for accommodating the substrate holder, the reaction tube having a top plate with a closed upper end and an opening for allowing the substrate holder to enter and exit from the reaction tube;

a cover that directly or indirectly holds the substrate holder and closes the opening; and

a gas supply mechanism for supplying a gas flow parallel to a front surface of each of the plurality of substrates held by the substrate holder in the reaction tube,

the substrate holder holds 1 or more dummy substrates having an Si sprayed layer formed on a front surface thereof at an end of the array, and holds a product substrate or a monitor substrate having an integrated circuit pattern formed thereon at other positions.

2. The substrate processing apparatus according to claim 1,

the Si sprayed layer formed on the front surface of the dummy substrate has a surface area substantially equal to that of the product substrate.

3. The substrate processing apparatus according to claim 1,

the product substrate has a via hole diameter or a trench width falling within a pore diameter range corresponding to 25% to 75% of the total volume in the cumulative pore volume distribution of the Si sprayed layer.

4. The substrate processing apparatus according to claim 1,

the substrate holder has a diameter less than half of that of the product substrate or the monitor substrate, and places and holds a plurality of dummy substrates having Si sprayed layers formed on the surfaces thereof on a tray.

5. The substrate processing apparatus according to claim 1 or 4, further comprising:

a furnace body surrounding the upper and side portions of the reaction tube; and

a controller for controlling the temperature of the furnace body and the gas supply mechanism so that a film having a predetermined thickness is deposited on the product substrate or the monitor substrate

The controller also holds, as an integrated value of film thickness, a history of processing that is held by the substrate holder and is processed together with the product substrate or the monitor substrate, for each of the plurality of dummy substrates.

6. The substrate processing apparatus according to claim 5,

the controller performs a predetermined recording operation, a notification operation, or an operation of removing the corresponding dummy substrate from the substrate holder when the integrated value exceeds a predetermined value.

7. The substrate processing apparatus according to claim 5, further comprising:

a lift for moving the cover up and down to carry the substrate holder in and out of the reaction tube; and

a cooler provided below the opening of the reaction tube and configured to spray a cooling gas toward the substrate holder being carried out or carried out,

the cooler is controlled to inject the cooling gas at a flow rate different from that at the time of non-contact when the injected cooling gas contacts the dummy substrate.

8. The substrate processing apparatus according to claim 7,

further comprising a particle counter for measuring particles in the gas of the cooling gas injected at a position opposed to the cooler,

the controller performs a predetermined recording operation, a notification operation, or an operation of removing the corresponding dummy wafer from the substrate holder when the particles measured by the particle counter from the cooling gas crossing the dummy wafer exceed a predetermined value.

9. A method of manufacturing a semiconductor device, comprising the steps of:

a step of carrying a substrate holder, which holds a plurality of substrates arranged at a predetermined interval, into a tubular reaction tube by using a carrying-in mechanism;

a step of adjusting the pressure inside the cylindrical reaction tube into which the substrate holder holding the substrate is carried by using a pressure adjusting section, and heating the reaction tube to a predetermined temperature by using a heater;

adjusting the pressure to supply a process gas from a gas supply unit into the tubular reaction tube heated to the predetermined temperature;

returning the interior of the cylindrical reaction tube to atmospheric pressure after the supply of the process gas is completed; and

a step of carrying out the substrate holder holding the substrate from the inside of the cylindrical reaction tube, the inside of which is returned to atmospheric pressure, using the carrying-in mechanism, and cooling the substrate to room temperature,

the supplying step is performed in a state where a product substrate or a monitor substrate on which an integrated circuit pattern is formed and a dummy substrate on which an Si fuse layer is formed on a surface thereof are aligned and held by the substrate holder, the dummy substrate being positioned on both sides of the product substrate or the monitor substrate.

10. The method according to claim 9, wherein in the supplying step, the temperature of the heater and the gas supplying portion are controlled by a controller so that a film having a predetermined thickness is deposited on the product substrate or the monitor substrate,

the method for manufacturing a semiconductor device further includes: using the controller, a history of processing together with the production substrate or the monitor substrate, which is held by the substrate holder, is held as an integrated value of film thickness for each of the plurality of dummy substrates, and a predetermined recording operation or a predetermined reporting operation is performed when the integrated value exceeds a predetermined value.

Technical Field

The present invention relates to a substrate processing apparatus for processing a substrate in a manufacturing process of a semiconductor device and a manufacturing method of a semiconductor device.

Background

For example, a vertical substrate processing apparatus is used for heat treatment of a substrate (wafer) in a process of manufacturing a semiconductor device. In a vertical substrate processing apparatus, a plurality of substrates are aligned and held in a vertical direction by a substrate holder, and the substrate holder is carried into a processing chamber. Thereafter, a process gas is introduced into the process chamber in a state where the process chamber is heated, and a thin film forming process is performed on the substrate.

Patent document 1 describes the following technique: the gas distribution adjusting member is provided with a plurality of concave and convex parts above and below the arrangement region of the plurality of the processed substrates held by the substrate holder. Further, it is described that two kinds of gas distribution adjusting members having different surface areas are used together.

Patent document 2 describes that a dummy wafer having the same surface area as that of a product wafer is used when a gate oxide film is deposited in a trench.

Patent document 3 discloses a vertical substrate processing apparatus in which the consumption amount of a processing gas is made to coincide with the vertical center of a substrate holder by a gas distribution adjusting mechanism that increases the surface area of the periphery of the upper and bottom portions of the substrate holder, thereby improving the uniformity of the film thickness between substrates. As the gas distribution adjusting mechanism, the following examples are disclosed: (1) arranging pattern dummy parts with a pattern magnification higher than that of the product substrate on the upper part and the bottom part of the substrate holder; (2) forming irregularities in upper and lower regions of the inner surface of the reaction tube by sand blasting; (3) unevenness is formed on the top plate and the bottom plate of the substrate holder by sandblasting.

Documents of the prior art

Patent document

Patent document 1: japanese patent laid-open publication No. 2017-22233

Patent document 2: japanese laid-open patent publication No. 2008-47785

Patent document 3: japanese patent laid-open publication No. 2015-173154

Disclosure of Invention

However, in the configurations described in patent documents 1 to 3, when a wafer having a very large processing surface area is processed, film thickness uniformity may be deteriorated among a plurality of wafers. In particular, the case where the uniformity is rapidly deteriorated at the upper and lower end portions of the wafer arrangement region is referred to as a load effect. If this occurs, the number of wafers taken out as products decreases, and productivity decreases.

According to the present disclosure, a technique is provided that can mitigate interfacial nonuniformity (load effect) of a plurality of wafers when the plurality of wafers having a large surface area are processed side by side, improve the process yield, and maintain the productivity.

One aspect of the present disclosure provides a technique of configuring a substrate processing apparatus including: a substrate holder configured to hold a plurality of substrates in a row at a predetermined interval; a reaction tube for accommodating the substrate holder, which has a top plate with a closed upper end and an opening for allowing the substrate holder to enter and exit from the reaction tube; a furnace body surrounding the upper and lateral sides of the reaction tube; a cover that directly or indirectly holds the substrate holder and closes the opening; and a gas supply mechanism for supplying a gas flow parallel to the front surface of each of the plurality of substrates held in the substrate holder in the reaction tube, wherein the substrate holder holds a product substrate or a monitor substrate on which an integrated circuit pattern is formed and a dummy substrate on which an Si thermal sprayed layer is formed on the front surface (front surface), and the dummy substrate is positioned on both sides of the product substrate or the monitor substrate.

Effects of the invention

According to the present disclosure, it is possible to alleviate interfacial unevenness (load effect) when processing a large surface area wafer, and to stably increase the number of wafers to be taken out as products compared with the conventional one, thereby maintaining high productivity.

Drawings

Fig. 1 is a longitudinal sectional view showing a schematic configuration of a vertical substrate processing apparatus according to embodiment 1 of the present disclosure.

Fig. 2 is a longitudinal sectional view showing a schematic configuration of a cleaning unit of a vertical substrate processing apparatus according to embodiment 1 of the present disclosure.

Fig. 3 is a transverse sectional view schematically showing the configuration of a transfer chamber of a vertical substrate processing apparatus according to example 1 of the present disclosure.

Fig. 4 is a longitudinal sectional view showing a schematic configuration of a processing furnace and a reaction tube of a vertical substrate processing apparatus according to example 1 of the present disclosure.

Fig. 5 is a block diagram showing a configuration of a controller of a vertical substrate processing apparatus according to embodiment 1 of the present disclosure.

Fig. 6 is a graph showing the analysis result of the distribution of radicals between the surfaces of stacked wafers in the case of processing a conventional large surface area wafer.

Fig. 7 is a graph showing cumulative pore volume distribution of the coating film of the Si dummy wafer in the vertical substrate processing apparatus according to example 1 of the present disclosure.

Fig. 8 is a graph showing the analysis result of the radical distribution between the surfaces of the stacked wafers in the vertical substrate processing apparatus according to example 1 of the present disclosure.

Fig. 9 is a flowchart showing a timing example of a film formation process for forming a film on 1 lot of wafers using the vertical substrate processing apparatus according to example 1 of the present disclosure.

Fig. 10 is a view of a Si thermal spraying dummy wafer processed by using the vertical substrate processing apparatus according to example 1 of the present disclosure, where (a) is a plan view and (b) is a front cross-sectional view.

Fig. 11 is a perspective view showing a tray in a state where a plurality of Si thermal sprayed wafers having a smaller diameter than the dummy wafer are mounted on the tray in the vertical substrate processing apparatus according to example 2 of the present disclosure.

Detailed Description

The present disclosure relates to a substrate processing apparatus, wherein when a large-wear pattern wafer is processed, Si meltallizing processing is performed on upper and lower dummy wafers. This can increase the surface area of the dummy wafer by several tens to several hundreds times. In addition, the surface area of the dummy wafer can be adjusted to be larger than or equal to the surface area of a product wafer to be processed by changing the thickness of the meltblown film in the Si meltblowing process.

Thus, the substrate processing apparatus of the present disclosure can be flexibly applied to processes of different film types and different development stages. In addition, the load effect caused by the consumption difference between the pattern wafer and the dummy wafer can be alleviated, and the uniformity between the surfaces can be improved.

In the substrate processing apparatus of the present disclosure, a plurality of small-diameter Si-fusion-shot wafers are mounted on a tray, and the surface area of the outer appearance on the tray is adjusted by changing the number of the Si-fusion-shot wafers mounted while keeping the thickness of the fusion-shot film constant.

According to the present disclosure, a technique is provided that can mitigate interfacial nonuniformity (load effect) of a plurality of wafers when the plurality of wafers having a large surface area are processed side by side, improve the process yield, and maintain the productivity.

Hereinafter, embodiments of the present disclosure will be described with reference to the drawings. The present disclosure is not limited to the embodiments described below, and includes various modifications. The embodiments described below are detailed for clearly and easily explaining the present disclosure, and the present disclosure is not limited to the embodiments having all the configurations described. Further, a part of the configuration of a certain embodiment may be replaced with another embodiment, and another embodiment may be added to the configuration of a certain embodiment. Further, addition, deletion, and replacement of another configuration may be performed with respect to a part of the configurations of the embodiments.

Example 1

A substrate processing apparatus and a method for manufacturing a semiconductor device according to embodiment 1 will be described with reference to fig. 1 to 10.

< Overall Structure of substrate processing apparatus >

In the present embodiment, the substrate processing apparatus is configured as a vertical substrate processing apparatus (hereinafter, referred to as a processing apparatus) 1 that performs a substrate processing step such as a heat treatment as one step of a manufacturing step in a manufacturing method of a semiconductor device (device). As shown in fig. 1, the processing apparatus 1 includes a transfer chamber 124 and a processing furnace 2 disposed above the transfer chamber 124.

The treatment furnace 2 includes: a cylindrical reaction tube 4 extending in the vertical direction; and a heater 3 (see fig. 4) of the 1 st heating unit (furnace body) provided on the outer periphery of the reaction tube 4. The reaction tube 4 is formed of, for example, quartz or SiC. A processing chamber 6 for processing a wafer 7 as a substrate is formed inside the reaction tube 4.

The cylindrical manifold 5 is connected to a lower end opening of the reaction tube 4 via a seal member such as an O-ring, and supports the lower end of the reaction tube 4. The manifold 5 is formed of metal such as stainless steel. The lower end opening of the manifold 5 is opened and closed by a disc-shaped shutter or cover 122, not shown. The lid portion 122 is formed in a disk shape from, for example, metal. A sealing member such as an O-ring is provided on the upper surface of the shutter plate and the lid 122, which are not shown, so that the inside of the reaction tube 4 is hermetically sealed from the outside air.

A heat insulating section 144 is placed on the cover section 122. The heat insulating portion 144 is formed of quartz, for example. The heat insulating part 144 has a cover heater 144a as a 2 nd heating means (heating means) on the surface or inside thereof. The lid heater 144a is configured to heat a substrate held below the process chamber 6 and below the wafer boat 126, which will be described later. A wafer boat 126 as a substrate holding unit is provided above the heat shield 144. The wafer boat 126 is composed of a top plate 126a, a bottom plate 126c, and a plurality of columns 126b provided between the top plate 126a and the bottom plate 126 c. The wafer boat 126 supports a plurality of, for example, 25 to 150 wafers 7 in multiple stages in the vertical direction by placing the wafers 7 in the multiple-stage grooves formed in the column 126 b. The boat 126 is made of, for example, quartz or SiC. The substrate holder 127 is constituted by the heat shield 144 and the boat 126. At the time of substrate processing, the substrate holder 127 is housed in the processing chamber 6.

The heat insulating portion 144 is connected to the rotating shaft 128 penetrating the cover 122. The rotation shaft 128 is connected to a rotation mechanism 130 provided below the cover 122. The heat shield 144 and the boat 126 can be rotated by rotating the rotating shaft 128 by the rotating mechanism 130.

In the transfer chamber 124, a substrate transfer unit 156, a boat 126, and a boat elevator 132 as an elevating mechanism are disposed. The substrate transfer unit 156 has an arm (tweezers) 156a capable of taking out, for example, 5 wafers 7. The substrate transfer unit 156 is configured to be capable of transferring the wafers 7 between the wafer cassette 160 placed at the position of the wafer cassette opener 158 and the boat 126 by vertically rotating the arm 156a by a driving mechanism, not shown. The boat elevator 132 moves the boat 126 in and out of the reaction tube 4 by vertically moving the lid 122. The transfer chamber 124 is configured as described later in detail.

The processing apparatus 1 includes a gas supply mechanism 134 for supplying a gas used for substrate processing into the processing chamber 6. The gas supplied by the gas supply mechanism 134 can be appropriately changed according to the type of film to be formed. The gas supply mechanism 134 includes a raw material gas supply unit (raw material gas supply system), a reaction gas supply unit (reaction gas supply system), and an inert gas supply unit (inert gas supply system).

The raw material gas supply system includes a gas supply pipe 9, and a Mass Flow Controller (MFC)10 as a flow controller (flow rate control unit) and a valve 11 as an on-off valve are provided in this order from the upstream side in the gas supply pipe 9. The gas supply pipe 9 is connected to a nozzle 8 penetrating the side wall of the manifold 5. The nozzle 8 is vertically erected in the reaction tube 4, and has a plurality of supply holes opened toward the wafers 7 held by the boat 126. The source gas is supplied to the wafer 7 through the supply hole of the nozzle 8.

Hereinafter, with the same configuration, the reaction gas is supplied from the reaction gas supply system to the wafer 7 through the gas supply pipe 9, the MFC10, the valve 11, and the nozzle 8. The reactive gas is supplied from the inert gas supply system to the wafer 7 through the gas supply pipe 12, the MFC13, the valve 14, and the nozzle 8.

An exhaust pipe 15 is attached to the manifold 5. A vacuum pump 18 as a vacuum exhaust device is connected to the exhaust pipe 15 via a Pressure sensor 16 as a Pressure detector (Pressure detecting unit) for detecting the Pressure in the processing chamber 6 and an APC (automatic Pressure Controller) valve 17 as a Pressure regulator (Pressure adjusting unit). With this configuration, the pressure in the processing chamber 6 can be set to a processing pressure corresponding to the processing.

Next, the configuration of the transfer chamber 124 according to the present embodiment will be described with reference to fig. 1 to 3.

As shown in fig. 2 and 3, the transfer chamber 124 is formed in a planar polygonal shape, for example, a planar rectangular parallelepiped shape (rectangular parallelepiped shape) by a ceiling plate, a bottom plate, and a side wall 120 surrounding the periphery. A cleaning unit 162 as a 1 st blowing unit (1 st gas supply unit) is provided on one side surface of the transfer chamber 124. A gas is supplied as clean air (clean ambient gas) from the cleaning unit 162 into the transfer chamber 124. Further, a circulation passage 174 for circulating gas is formed in a space located around the transfer chamber 124. The gas supplied into the transfer chamber 124 is exhausted from the side exhaust portion 172a, and is supplied again into the transfer chamber 124 from the cleaning unit 162 via the circulation passage 174. A radiator, not shown, is provided in the middle of the circulation passage 174, and the gas is cooled by passing through the radiator.

The cleaning unit 162 is disposed such that the upper cleaning unit 162a and the lower cleaning unit 162b are vertically adjacent to each other. The upper cleaning unit 162a is configured to supply gas into the transfer chamber 124, particularly, into the boat 126. The lower cleaning unit 162b is configured to supply gas into the transfer chamber 124, particularly, into the heat insulating portion 144. Hereinafter, the case of being referred to as the cleaning unit 162 includes a case of representing the upper cleaning unit 162a, a case of representing the lower cleaning unit 162b, or both of them.

The cleaning unit 162 includes a fan 164 as an air blowing unit, a buffer 166 as a buffer chamber, a filter unit 168, and a gas supply port 170 in this order from the upstream side. The buffer area 166 is a diffusion space for uniformly blowing the gas from the entire surface of the gas supply port 170. The filter unit 168 is configured to remove particles contained in the gas. The upper cleaning unit 162a and the lower cleaning unit 162b are each provided with a fan 164, a buffer 166, a filter section 168, and a gas supply port 170.

A side exhaust section 172a and the boat elevator 132 are provided on one side surface of the cleaning unit 162 on the opposite side. The gas supplied from the upper cleaning unit 162a into the transfer chamber 124 is mainly exhausted from the side exhaust portion 172a, and is supplied from the cleaning unit 162 into the transfer chamber 124 again through the circulation passage 174. Thus, a gas flow (side flow) in the horizontal direction (direction parallel to the wafer 7) is formed in the upper region (wafer 7 region) in the transfer chamber 124.

As shown in fig. 3, a pair of bottom surface exhaust portions 172b are provided on the bottom surface of the transfer chamber 124 with the boat 126 interposed therebetween. The bottom surface exhaust portion 172b is formed in a rectangular shape along one side of the transfer chamber 124. The gas supplied from the lower cleaning unit 162b into the transfer chamber 124 is mainly exhausted from the bottom surface exhaust portion 172b, and is supplied from the cleaning unit 162 into the transfer chamber 124 again through the circulation passage 174. Thereby, a gas flow (downward flow) in the vertical direction is formed in the lower region (the heat insulating portion 144 region) in the transfer chamber 124.

As shown in fig. 2 and 3, a gas pipe 176 serving as a 2 nd blowing unit (2 nd gas supply unit) is provided on a side surface other than the side surface opposite to the side surface on which the cleaning unit 162 is provided. For example, the gas pipe 176 is disposed on a side surface adjacent to a side surface on which the cleaning unit 162 is disposed. In the present embodiment, the gas pipe 176 is provided at a position facing the substrate transfer unit 156 in the transfer chamber 124 (a position between the side surface of the transfer chamber 124 and the boat 126) with the boat 126 therebetween. The gas pipe 176 is configured to supply gas to a region below the lowermost substrate placed on the boat 126. Preferably, the gas pipe 176 is configured to supply gas to a region between the lowermost substrate of the boat 126 and the heat shield 144.

As shown in fig. 2, the gas pipe 176 is provided horizontally in the transfer chamber 124, and has a blow-out port 176a opening toward the substrate holder 127. The gas is supplied into the transfer chamber 124, particularly the substrate holder 127, through the outlet port 176a of the gas pipe 176. Examples of the gas include an inert gas. The gas pipe 176 is connected to a transfer chamber gas supply mechanism 178 that supplies gas into the transfer chamber 124. The transfer chamber gas supply mechanism 178 includes a gas supply pipe 136c, and the gas supply pipe 136c is provided with an MFC138c and a valve 140c in this order from the upstream side.

The gas pipe 176 is provided so that the height position of the blow-out port 176a is maintained at the height position between the heat shield 144 and the substrate at the lowermost layer of the boat 126. As shown in fig. 3, the air outlet 176a is formed by a plurality of openings. When the blow ports 176a are formed by an even number of holes, the same number of holes are formed on the left and right across the center line of the wafer 7. In the case where the air outlet 176b is formed of an odd number of openings, 1 opening is formed at the center line of the wafer 7, and the same number of openings are formed to the left and right of 1 opening. In the present embodiment, the air outlet 176a is formed with 5 openings having a diameter of, for example, 1mm or less. The blow-out port 176a is formed in a region within the diameter range of the wafer 7 in plan view. In other words, the opening (forming) range of the blowing port 176a is formed so as to fall within the range of the diameter of the wafer 7. With this configuration, the direction of the main flow of the gas supplied from the outlet 176a can be set to the horizontal direction. Thus, a gas barrier (gas curtain) can be formed in the space between the lowermost substrate of the wafer boat 126 and the heat insulating portion 144, and the upper ambient gas on the wafer boat 126 side (ambient gas in the wafer 7 region) and the lower ambient gas on the heat insulating portion 144 side (ambient gas in the heat insulating portion 144 region) can be separated by the gas curtain.

As shown in fig. 1, the controller 29 for controlling the rotation mechanism 130, the boat elevator 132, the substrate transfer unit 156, the gas supply mechanism 134 (MFCs 10, 13 and valves 11, 14), the APC valve 17, the cleaning unit 162, and the transfer chamber gas supply mechanism 178(MFC138c and valve 140c) is connected thereto. The controller 29 is constituted by, for example, a microprocessor (computer) provided with a CPU, and is configured to control the operation of the processing device 1.

As shown in fig. 4, the treatment furnace 2 includes a heater 3 as a main heater disposed in the vertical direction to heat the cylindrical portion of a reaction tube 4 described later. The heater 3 has a cylindrical shape and is vertically arranged around a cylindrical portion (side portion in the present embodiment) of the reaction tube 4 described later. The heater 3 is constituted by a plurality of heater units divided into a plurality in the vertical direction. In the present embodiment, the heater 3 includes an upper heater 3A, a center upper heater 3B, a center heater 3C, a center lower heater 3D, and a lower heater 3E from the top. The heater 3 is supported by a heater base (not shown) as a holding plate, and is vertically mounted on a mounting base plate of the substrate processing apparatus 1.

The upper heater 3A, the central upper heater 3B, the central heater 3C, the central lower heater 3D, and the lower heater 3E are electrically connected to the power conditioner 70. The power conditioner 70 is electrically connected to the controller 29. The controller 29 functions as a temperature controller for controlling the amount of current supplied to each heater by the power conditioner 70. The controller 29 controls the amount of current supplied to the power conditioner 70, thereby controlling the temperatures of the upper heater 3A, the center upper heater 3B, the center heater 3C, the center lower heater 3D, and the lower heater 3E. The heater 3 also functions as an activation mechanism (activation unit) for activating (activating) the gas by heat as described later.

A reaction tube 4 constituting a reaction vessel (processing vessel) is disposed inside the heater 3. The reaction tube 4 is made of, for example, quartz (SiO)₂) Or a heat-resistant material such as silicon carbide (SiC), and is formed into a cylindrical shape having a closed upper end and an open lower end. The reaction tube 4 has a 2-fold tube structure having an outer tube 4A and an inner tube 4B joined to each other at a flange portion 4C at the lower end. In other words, the outer tube 4A and the inner tube 4B are each formed in a cylindrical shape, and the inner tube 4B is disposed inside the outer tube 4A. The outer tube 4A is provided with a top plate portion 72 whose upper end is closed. Further, a top plate 74 is provided on the inner tube 4B to close the upper end, and the lower end of the inner tube 4B is open. The top plate 74 is formed in a shape having a flat inner surface. The outer tube 4A is disposed so as to surround the upper and side portions of the inner tube 4B.

A flange portion 4C is provided at a lower portion of the outer tube 4A. The flange portion 4C has a larger outer diameter than the outer tube 4A and projects outward. An exhaust port 4D communicating with the inside of the outer tube 4A is provided near the lower end of the reaction tube 4. The entire reaction tube 4 including the above portions is integrally formed of a single material. The outer tube 4A is formed to be thick so as to be able to withstand a pressure difference when the inside is evacuated.

The treatment furnace 2 includes a side heat insulator 76 and an upper heat insulator 78 disposed on the upper side of the heater 3 so as to cover the obliquely upper side and the upper side of the top plate portion 72 of the outer tube 4A. For example, a cylindrical side heat insulator 76 is provided above the heater 3, and an upper heat insulator 78 is fixed to the side heat insulator 76 in a state of being laid over the side heat insulator 76. Thus, the treatment furnace 2 is configured to surround the upper and side portions of the reaction tube 4.

A ceiling heater 80 for heating the ceiling portion 72 of the outer tube 4A and the ceiling 74 of the inner tube 4B of the reaction tube 4 is provided above the ceiling portion 72 of the outer tube 4A and on the lower wall portion of the upper heat insulator 78. In the present embodiment, the ceiling heater 80 is provided outside the outer tube 4A. The ceiling heater 80 is electrically connected to the power conditioner 70. The controller 29 controls the amount of electricity supplied to the ceiling heater 80 by the power conditioner 70. Thereby, the temperature of the ceiling heater 80 is controlled independently of the temperatures of the upper heater 3A, the center upper heater 3B, the center heater 3C, the center lower heater 3D, and the lower heater 3E.

The manifold 5 is cylindrical or circular truncated cone-shaped, made of metal or quartz, and is provided to support the lower end of the reaction tube 4. The inner diameter of the manifold 5 is formed larger than the inner diameter of the reaction tube 4 (inner diameter of the flange portion 4C). This forms an annular space (described later) between the lower end (flange 4C) of the reaction tube 4 and the seal cap 19 (described later). The space or the members around the space are collectively referred to as a furnace opening.

The inner tube 4B has a main exhaust port 4E on its side surface and on the inner side of the reaction tube with respect to the exhaust port 4D, the inner side of which communicates with the outer side, and a supply slit 4F at a position opposite to the main exhaust port 4E. The main exhaust port 4E may be a single long-sized opening that opens to a region where the wafer 7 as a substrate is disposed, or may be a plurality of slits extending in the circumferential direction (see fig. 1). The supply slit 4F is a slit extending in the circumferential direction, and a plurality of supply slits are provided in parallel in the vertical direction so as to correspond to the wafers 7.

In the exhaust space S between the outer tube 4A and the inner tube 4B, 1 or more nozzles 8 for supplying a process gas such as a source gas are provided corresponding to the positions of the supply slits 4F. Gas supply pipes 9 for supplying process gases (source gases) penetrate the manifold 5 and are connected to the nozzles 8, respectively. The processing gas discharged from the nozzle 8 flows in parallel to the front surface of the wafer 7 in the gap between the wafers 7 (the uppermost wafer is the gap between the wafer boat top plate 21B) so as to traverse the end portions of the wafers 7.

A Mass Flow Controller (MFC)10 as a flow controller and a valve 11 as an on-off valve are provided in this order from the upstream side in the flow path of each gas supply pipe 9. A gas supply pipe 12 for supplying an inert gas is connected to the gas supply pipe 9 on the downstream side of the valve 11. The gas supply pipe 12 is provided with an MFC13 and a valve 14 in this order from the upstream side. The gas supply mechanism as a process gas supply system is mainly constituted by the gas supply pipe 9, the MFC10, and the valve 11.

The nozzle 8 is provided in the gas supply space S1 so as to rise from the lower portion of the reaction tube 4. One or more nozzle holes 8H for supplying gas are provided in the side surface and the upper end of the nozzle 8. The plurality of nozzle holes 8H are opened so as to correspond to the openings of the supply slits 4F and face the center of the reaction tube 4, and can inject gas to the wafer 7 through the inner tube 4B.

An exhaust pipe 15 for exhausting the ambient gas in the processing chamber 6 is connected to the exhaust port 4D. A vacuum pump 18 as a vacuum exhaust device is connected to the exhaust pipe 15 via a Pressure sensor 16 as a Pressure detector (Pressure gauge) for detecting the Pressure in the processing chamber 6 and an APC (automatic Pressure Controller) valve 17 as a Pressure regulator (Pressure adjusting unit). The APC valve 17 opens and closes the valve in a state where the vacuum pump 18 is operated, thereby enabling vacuum evacuation and vacuum evacuation stop in the processing chamber 6. The APC valve 17 is configured to be able to adjust the pressure in the processing chamber 6 by adjusting the valve opening degree based on the pressure information detected by the pressure sensor 16 in a state where the vacuum pump 18 is operated. The exhaust system is mainly constituted by an exhaust pipe 15, an APC valve 17, and a pressure sensor 16. It is also contemplated that vacuum pump 18 may be included in the exhaust system.

A seal cap 19 of a cap capable of hermetically closing the opening 90 at the lower end of the manifold 5 is provided below the manifold 5. That is, the seal cap 19 functions as a cap (shutter) for closing the outer tube 4A of the reaction tube 4. The seal cover 19 is formed of a metal such as stainless steel or nickel-based alloy, and is formed in a circular plate shape. An O-ring 19A as a sealing member is provided on the upper surface of the seal cap 19 so as to abut against the lower end of the manifold 5.

Further, a cover plate 20 for protecting the seal cover 19 is provided on the upper surface of the seal cover 19, with respect to a portion of the manifold 5 inside the lower end inner periphery. The cover plate 20 is formed of a heat-resistant and corrosion-resistant material such as quartz, sapphire, or SiC, and is formed in a circular plate shape. The cover plate 20 does not require mechanical strength and can be formed with a thin wall. The cover plate 20 is not limited to a member prepared separately from the sealing lid 19, and may be a thin film or layer of nitride or the like applied to or modified from the inner surface of the sealing lid 19. The cover plate 20 may have a wall that rises from the circumferential edge along the inner surface of the manifold 5.

A wafer boat 21 (corresponding to the wafer boat 126 in fig. 1) as a substrate holder is housed inside the inner tube 4B of the reaction tube 4. The boat 21 includes a plurality of upright support columns 21A and a disk-shaped boat top plate 21B that fixes upper ends of the plurality of support columns 21A to each other. Here, the boat top plate 21B is an example of a top plate. In the present embodiment, the wafer boat 21 has an annular bottom plate 21C at the lower end portions of the plurality of support columns 21A, but a disk-shaped bottom plate may be provided instead.

The wafer boat 21 supports, for example, 25 to 200 wafers 7 in a horizontal posture in a plurality of stages in a vertical direction with their centers aligned with each other. Thus, the wafers 7 are arranged at constant intervals. The wafer boat 21 is made of a heat-resistant material such as quartz or SiC.

The inner tube 4B of the reaction tube 4 preferably has a minimum inner diameter that allows the boat 21 to be safely carried in and out. In the present embodiment, for example, the diameter of the boat top plate 21B is set to 90% to 98% of the inner diameter of the inner tube 4B, or the interval between the wafers 7 held by the boat 21 is set to 6mm to 16mm, for example. Here, the diameter of the boat top plate 21B is preferably 90% to 98%, more preferably 92% to 97%, and still more preferably 94% to 96% of the inner diameter of the inner tube 4B.

By setting the diameter of the boat top plate 21B to 90% or more of the inner diameter of the inner tube 4B, the gap between the edge of the boat top plate 21B and the inner tube 4B can be reduced, and gas movement due to diffusion (particularly, the flow of residual radicals described later from the boat top plate 21B to the wafer 7 side) can be suppressed. Further, by setting the diameter of the boat top plate 21B to 98% or less of the inner diameter of the inner tube 4B, the boat 21 can be safely carried in and out from the inner tube 4B.

The interval between the wafers 7 is preferably 6mm to 16mm, more preferably 7mm to 14mm, and still more preferably 8mm to 12 mm. By setting the interval between the wafers 7 to 6mm or more, the gas can smoothly flow between the adjacent wafers 7. Further, by setting the interval between the wafers 7 to 16mm or less, more wafers 7 can be processed.

In the present embodiment, the volume of the upper end space sandwiched by the boat top plate 21B and the other part and the top plate 74 and the boat top plate 21B is set to be, for example, 1 to 3 times the volume of the space sandwiched by the mutually adjacent (adjacent) wafers 7 held in the boat 21.

Here, the volume of the upper end space sandwiched by the top plate 74 and the boat top plate 21B is preferably 1 time or more and 3 times or less, more preferably 1 time or more and 2.5 times or less, and still more preferably 1 time or more and 2 times or less, the volume of the space sandwiched by the mutually adjacent wafers 7. That is, the smaller the volume of the upper end space sandwiched between the top plate 74 and the boat top plate 21B, the better. But requires the gas to flow smoothly to the main exhaust port 4E.

The absolute amount of excess gas is reduced by setting the volume of the upper end space sandwiched between the top plate 74 and the boat top plate 21B to be 3 times or less the volume of the space sandwiched between the mutually adjacent wafers 7 held in the boat 21. Further, the volume of the upper end space sandwiched between the top plate 74 and the boat top plate 21B is 1 time or more of the volume of the space sandwiched between the mutually adjacent wafers 7 held in the boat 21, whereby the gas flows smoothly to the main exhaust port 4E.

A heat insulating unit (heat insulating structure) 22 described later is disposed below the boat 21. The heat insulating module 22 has a structure for minimizing heat conduction or heat transfer in the up-down direction, and generally has a hollow space therein. The interior can be purged with a shaft purge gas. In the reaction tube 4, an upper portion where the boat 21 is disposed is referred to as a processing region a of the wafers 7, and a lower portion where the heat shield assembly 22 is disposed is referred to as a heat shield region B.

A rotation mechanism 23 (corresponding to the rotation mechanism 130 in fig. 1) for rotating the boat 21 is provided on the side of the seal lid 19 opposite to the process chamber 6. A gas supply pipe 24 for shaft purge gas is connected to the rotating mechanism 23. The gas supply pipe 24 is provided with an MFC25 and a valve 26 in this order from the upstream side. The purpose of this purge gas is to protect the inside (e.g., bearings) of the rotation mechanism 23 from corrosive gases and the like used in the process chamber 6. The purge gas is supplied from the rotating mechanism 23 along the rotating shaft 66 (corresponding to the rotating shaft 128 in fig. 1) and is guided into the heat shield assembly 22.

The boat elevator 27 (corresponding to 132 in fig. 1) is vertically provided below the outside of the reaction tube 4, and operates as an elevating mechanism (conveyance mechanism) for elevating and lowering the seal cap 19. Thereby, the boat 21 and the wafers 7 supported by the seal cover 19 are carried into and out of the processing chamber 6. Further, a shutter plate (not shown) for closing the lower end opening of the reaction tube 4 may be provided instead of the seal cap 19 while the seal cap 19 is lowered to the lowermost position.

A temperature sensor (temperature detector) 28 as a processing space temperature sensor for detecting the temperature inside the reaction tube 4 is provided on the outer wall of the side portion of the outer tube 4A or on the inner side of the inner tube 4B. The temperature sensor 28 is constituted by a plurality of thermocouples arranged in parallel, for example, up and down. Although not shown, the temperature sensor 28 is electrically connected to the controller 29. The controller 29 adjusts the amount of current supplied to the upper heater 3A, the central upper heater 3B, the central heater 3C, the central lower heater 3D, and the lower heater 3E by the power adjuster 70 based on the temperature information detected by the temperature sensor 28 so that the temperature in the processing chamber 6 has a desired temperature distribution.

A temperature sensor (temperature detector) 82 as an upper end space temperature sensor for detecting the temperature of the upper portion in the reaction tube 4 is provided on the outer wall of the top plate portion 72 of the outer tube 4A. The temperature sensor 82 is constituted by, for example, a plurality of thermocouples arranged in parallel in the horizontal direction. Although not shown, the temperature sensor 82 is electrically connected to the controller 29. The controller 29 adjusts the amount of power supplied to the ceiling heater 80 by the power conditioner 70 based on the temperature information detected by the temperature sensor 82, thereby making the temperature of the upper portion in the processing chamber 6a desired temperature distribution.

As shown in fig. 1, the transfer chamber 124 is provided with a spatial particle measurement port (hereinafter referred to as a particle measurement port) 400 as a measurement port, the particle measurement port 400 collects particles for particle measurement, and the particle measurement port 400 is connected to a spatial particle counter (hereinafter referred to as a particle counter) 402 as a counter for particle measurement in a pipe 401. A particle measuring device as a measuring device for measuring particles floating in a space is composed of a particle measuring port 400, a tube 401, and a particle counter 402. The particle counter 402 is connected to a controller 29 described later.

The particle counter 402 includes a pump therein, and sucks ambient air from the particle measurement port 400. When the boat 21 starts to descend from the inside of the processing furnace 2, that is, when the seal lid 19 is separated from the lower end portion of the processing furnace 2 and the furnace opening 61 is opened, the controller 29 sends a signal "start of measurement" to the particle counter 402. Upon receiving the "measurement start" signal from the controller 29, the particle counter 402 resets the number of particles stored before the start of measurement to 0 (zero), detects the number of particles contained in the sucked ambient gas, counts the number of particles cumulatively, and records the number as the cumulative number of particles. The controller 29 may display the number of particles sent from the particle counter 402 on a display screen (hereinafter referred to as a screen) of the input/output device 222 (see fig. 5).

With this particle counter 402, measurement is performed downstream thereof during the supply of the cooling gas. When the particles measured by the particle counter 402 from the cooling gas that has passed through the dummy wafers stored in the boat 21 and formed with the sprayed coating exceed a predetermined value, the controller 29 performs a predetermined recording operation, a predetermined notification operation, or an operation of removing the corresponding dummy wafers from the boat 21. That is, since the surface shape of the spray coating is very random, the possibility that the SiN film formed thereon has a peculiar local shape which is easily peeled off cannot be denied. Therefore, it is effective to actually form a film, find a dummy wafer in which particles are likely to be generated, and remove the dummy wafer.

As shown in fig. 5, the controller 29 is electrically connected to and automatically controls the MFCs 10, 13, 25, and 138c, the valves 11, 14, 26, and 140c, the pressure sensor 16, the APC valve 17, the vacuum pump 18, the rotation mechanisms 23 and 130, and the boat elevator 132 (corresponding to the boat elevator 27 in fig. 4). The controller 29 is electrically connected to and automatically controls the heaters 3 (the upper heater 3A, the central upper heater 3B, the central heater 3C, the central lower heater 3D, and the lower heater 3E), the top plate heater 80, the lid heater 34 (corresponding to the lid heater 144a in fig. 1), the temperature sensors 28 and 82, and the like. Although not shown, the controller 29 is electrically connected to the heaters 3 (the upper heater 3A, the central upper heater 3B, the central heater 3C, the central lower heater 3D, and the lower heater 3E), the ceiling heater 80, and the lid heater 34, respectively, via the power conditioner 70.

The controller 29 is configured by a computer including a CPU (Central Processing Unit) 212, a RAM (Random Access Memory) 214, a storage device 216, and an I/O port 218. The RAM214, the storage device 216, and the I/O port 218 are configured to be able to exchange data with the CPU212 via an internal bus 220. The I/O port 218 is connected to each of the above components. An input/output device 222 such as a touch panel and an external storage device 224 are connected to the controller 29.

The storage device 216 is configured by, for example, a flash memory, an HDD (Hard Disk Drive), or the like. In the storage device 216, a control program for controlling the operation of the substrate processing apparatus 1 and programs (processes such as a process step and a cleaning step) for causing the respective components of the substrate processing apparatus 1 to perform a film forming process in accordance with processing conditions are stored so as to be readable. The RAM214 is configured as a memory area (work area) that temporarily holds programs, data, and the like read by the CPU 212.

The CPU212 reads and executes the control program from the storage device 216, and reads the process from the storage device 216 in accordance with input of an operation command from the input/output device 222, and the like, and controls each configuration in accordance with the process.

The controller 29 can be configured by installing the program, which is continuously stored in the external storage device (for example, a semiconductor memory such as a USB memory or a memory card, an optical disk such as a CD or a DVD, or an HDD)224, in the computer. The storage device 216 and the external storage device 224 are configured as computer-readable tangible media. Hereinafter, the above will be also simply referred to as "recording medium". Note that the program may be provided to the computer by using a communication means such as the internet or a dedicated line without using the external storage device 224.

The controller 29 manages the use history of each dummy substrate. That is, for each dummy substrate, a history of processing together with the product wafer held by the substrate holder is held as an integrated value of film thickness. When the integrated value exceeds a predetermined value, a predetermined recording operation, a notification operation, or an operation of removing the corresponding dummy wafer from the substrate holder is performed.

In such a configuration, the analysis result of the inter-surface radical distribution when a large-surface-area wafer (a surface area having an integrated circuit pattern with irregularities formed on the front surface thereof, for example, 100 times that of a bare wafer having a flat surface) as the wafer 7 is treated by a conventional method is shown in fig. 6. This is correlated with the film thickness distribution. In the vertical type apparatus, normally, a process of loading a plurality of dummy wafers 620, which are not used as products, on the upper and lower ends of the boat 126 is performed in addition to the wafer 7 (product wafer 610) used as a product. This is primarily to ensure temperature uniformity of the production wafer 610. In this example, the product wafers 610 are loaded in the slits 8 to 107, and 7 to 8 dummy wafers 620 are loaded at both ends thereof at the same intervals as the product wafers 610, respectively.

In the conventional method shown in fig. 6, it is known that the partial pressure of radicals increases at the upper and lower ends of a product wafer 610 (wafer having a circuit pattern formed on the surface thereof, hereinafter referred to as a pattern wafer), and the uniformity deteriorates. This is because the pattern wafer 610 has a large surface area and consumes a large amount of radicals, and therefore the radical concentration in the gas phase is low, while the dummy wafer 620 having a small surface area consumes a small amount of radicals, and therefore the radical concentration in the gas phase is high.

In the region where the pattern wafer 610 and the dummy wafer 620 are adjacent to each other, where such an extreme concentration difference is formed, diffusion occurs in the concentration in the gas phase, and the radical concentration difference tends to be alleviated. Therefore, the concentration inevitably increases at the upper and lower ends of the production wafer 610 (the film thickness becomes thicker), and the uniformity deteriorates. As such, a loading effect occurs due to the difference between the dummy wafer 620, which has substantially no consumption of radicals, and the pattern wafer 610, which has a heavy consumption (proportional to the surface area).

As a countermeasure for this, it is conceivable to increase the surface area on the dummy wafer by performing Si meltblowing treatment on the dummy wafer without using the conventional dummy wafer 620. By making the surface area of the dummy wafer larger than or equal to that of the pattern wafer, the difference in consumption between the dummy wafer and the pattern wafer can be eliminated, and the load effect can be reduced. In addition, if only the surface of the dummy wafer is roughened, the surface area is only several times that of the bare wafer, and thus the dummy wafer cannot cope with a pattern wafer having a large surface area. On the other hand, when the Si thermal spray treatment of the present method is used, the surface area can be increased to several tens to several hundreds times that of the bare wafer.

[ method for producing Si thermal spraying dummy wafer ]

In general, a dummy wafer is often prepared by regrinding a defective wafer generated in a device manufacturing process or the like. The Si meltblowing dummy wafer 820 (see fig. 10) of the present embodiment may be made of such a dummy wafer (bare dummy). In the Si sputtering dummy wafer of the present example, a Si sputtering coating 822 is formed by Si sputtering on the surface of the single crystal Si wafer on the front side of the bare dummy 821. The meltblowing can be roughly divided into thermal spraying for melting a raw material into droplets (fine particles) and blowing the droplets and cold spraying for blowing a solid powder at a critical velocity or higher, and both of them can be used.

At this time, the pores in the Si sprayed film 822 of the Si sprayed dummy wafer 820 are continuous pores, and it is necessary to stably perform spraying under a condition of an appropriately high porosity in order to obtain a large surface area. In this respect, when the melting and jetting is performed at a low temperature, scattering (splat) of the fine particles flattened by being hit against the base material is preferably not excessively adhered. The porous film thus formed has many continuous pores opened on the surface, and the surface area thereof is proportional to the film thickness (volume), and the proportionality constant is also referred to as a specific surface area.

After the Si sprayed coating 822 is formed by Si spraying, the Si sprayed dummy wafer 820 is cleaned (for example, modified RCA cleaning) and dried similarly to the product wafer 810 (corresponding to the pattern wafer 610), and further inspected for foreign matter (particles) by using a wafer surface inspection apparatus or the like as necessary.

In order to reproduce the radical consumption at the time of film formation on the production wafer 810 as faithfully as possible, it may be preferable to make the diameter of the micropores in the film of the Si thermal spraying dummy wafer 820 correspond to the size of the pattern of the production wafer 810 (the diameter of the via hole, the width of the trench). For example, the via hole used in 3D NAND has a diameter of 50nm or less. On the other hand, the diameter of the fine pores of the sprayed film formed by Si spraying can be controlled to some extent by the size of the fine particles to be sprayed.

Fig. 7 shows an example of a cumulative pore volume distribution 701 of a preferred Si sprayed film 822 formed on a Si sprayed dummy wafer 820. When the dimension of the pattern of the product wafer 810 is set to 50nm, the cumulative pore volume is about 40%. As described above, the diameter of the via hole or the width of the trench included in the product wafer 810 preferably falls within the range of pore diameters corresponding to 25% to 75% of the total volume in the cumulative pore volume distribution 701. If the pore diameter corresponding to 75% of the cumulative volume is smaller than the pattern size, the pores are too small, and therefore, not only the pores are easily closed, but also other phenomena such as capillary condensation occur, and there is a possibility that the simulation of the product wafer 810 cannot be performed. On the other hand, if the pore diameter corresponding to the cumulative volume of 25% is larger than the pattern size, the pores may be too large to be faithfully simulated.

Alternatively, the sintered coating using Si sintering may be made porous by anodic oxidation in an aqueous hydrofluoric acid solution, thereby forming mesopores having a size equivalent to the pattern formed on the production wafer 810. In this case, the surface area S is expressed by the following equation:

S＝S_s0×t_s×(1+S_p0×t_p),

here, t_sFor the duration of the meltdown process, S_s0Is the surface area formed per unit time by the meltblowing, t_sFor anodic oxidation time, S_p0For a short time increased surface area by anodic oxidation, S_s0And S_p0Obtained empirically.

[ film formation simulation ]

Fig. 8 shows the analysis result of the distribution of radicals between the surfaces when the surface areas of the Si-fired dummy wafer 820 and the product wafer 810 on which the circuit pattern is formed are the same. Although this calculation is performed by a model simpler than that of an actual apparatus, it is shown that if there is no consumption difference between the Si meltallizing dummy wafer 820 and the product wafer 810, the upper and lower ends are flat, and the distribution of radicals between the surfaces is uniform. By suppressing the difference in the radical concentration, the load effect can also be eliminated. Unless it is CVD with controlled feed rate, the radical partial pressure is not immediately proportional to the film thickness, but preferably the concentration difference is, for example, within 5%.

In an actual apparatus, the uniformity of the Si thermal spraying dummy wafer 820 having a surface area slightly larger than that of the product wafer 810 may be improved due to the influence of the presence of radicals or the like at a high concentration in the space between the boat top plate and the reaction tube.

In the Si sprayed layer of the present method, the thickness of the sprayed film is substantially proportional to the surface area, and therefore the surface area increases as the thickness of the sprayed film increases. That is, the surface area can be freely adjusted by changing the thickness of the meltblown film. Therefore, even when the pattern formed on the front surface changes due to the type and the development stage of the film and the surface area of the product wafer 810 changes, the pattern can be flexibly handled in accordance with the change.

[1 batch (batch) film formation Process steps ]

Next, a timing example of a process (hereinafter, also referred to as a film forming process) of forming a film on 1 lot of wafers 7 using the substrate processing apparatus 1 as one step of a manufacturing process of semiconductor devices (devices) will be described mainly based on the configuration shown in fig. 4 with reference to fig. 9.

(wafer filling and boat loading): s901

The wafer boat 21 (wafer boat 126 in fig. 1) holds a plurality of product wafers having patterns formed thereon at all positions where the wafers 7 can be held. When a plurality of wafers 7 are loaded in the boat 21 (wafer loading), the boat 21 is carried into the processing chamber 6 by the boat elevator 27 (the boat elevator 132 in fig. 1) (boat loading). At this time, the seal cap 19 is in a state of hermetically closing (sealing) the lower end of the manifold 5 via the O-ring 19A. The valve 26 can be opened from a standby state before filling the wafer, and a small amount of purge gas can be supplied into the cylindrical portion 39.

(pressure adjustment): s902

Vacuum evacuation (reduced pressure evacuation) is performed by the vacuum pump 18 so that the pressure (degree of vacuum) in the processing chamber 6, that is, the space in which the wafer 7 is located is a predetermined pressure. At this time, the pressure in the processing chamber 6 is measured by the pressure sensor 16, and the APC valve 17 performs feedback control based on the measured pressure information. The supply of the purge gas into the cylindrical portion 39 and the operation of the vacuum pump 18 are maintained at least until the end of the process for the wafer 7.

(temperature raising step): s903

After the oxygen gas and the like are sufficiently exhausted from the inside of the processing chamber 6, the temperature rise in the processing chamber 6 is started. Based on the temperature information detected by the temperature sensor 28, the amount of current supplied to the heaters 3 (the upper heater 3A, the central upper heater 3B, the central heater 3C, the central lower heater 3D, and the lower heater 3E) is feedback-controlled so that the process chamber 6 has a predetermined temperature distribution suitable for film formation. Further, the amount of current supplied to the ceiling heater 80 is feedback-controlled based on the temperature information detected by the temperature sensor 82.

The heating in the processing chamber 6 by the heaters 3 (the upper heater 3A, the central upper heater 3B, the central heater 3C, the central lower heater 3D, and the lower heater 3E), the ceiling heater 80, and the lid heater 34 is continued at least until the end of the process (film formation) on the wafer 7. The energization period to the lid heater 34 does not need to coincide with the heating period in which the heater 3 heats. It is preferable that the temperature of the lid heater 34 be the same as the film formation temperature and the temperature of the inner surface of the manifold 5 be 180 ℃ or higher (e.g., 260 ℃) immediately before the start of film formation.

Further, the rotation of the wafer boat 21 and the wafers 7 by the rotation mechanism 23 is started. The wafer boat 21 is rotated by the rotation mechanism 23 via the rotation shaft 66, the turntable 37, and the cylindrical portion 39, whereby the wafer 7 is rotated without rotating the lid heater 34. This reduces uneven heating. The rotation of the boat 21 and the wafers 7 by the rotation mechanism 23 is continued at least until the end of the process on the wafers 7.

(film formation step): s904

If the temperature in the processing chamber 6 is stabilized at the predetermined processing temperature in S903, step 1: s9041-step 4: and S9044. Further, in step 1: the purge gas (N) was added by opening the valve 26 before starting S9041₂) Is supplied.

[ step 1: raw material gas supply step ]: s9041

In step 1, HCDS gas is supplied to the wafer 7 in the process chamber 6. The valve 11 was opened and the valve 14 was opened to flow HCDS gas into the gas supply pipe 9 and to supply N₂The gas flows into the gas supply pipe 12. HCDS gas and N₂The gas is supplied into the processing chamber 6 through the nozzle chamber 42 and exhausted from the exhaust pipe 15 while the flow rates of the gases are adjusted by the MFCs 10 and 13, respectively. By supplying HCDS gas to the wafer 7, a silicon (Si) -containing film, for example, is formed as the 1 st layer on the outermost surface of the wafer 7.

[ step 2: raw material gas exhaust step ]: s9042

After the formation of the 1 st layer, the valve 11 was closed to stop the supply of the HCDS gas. At this time, the inside of the process chamber 6 is evacuated by the vacuum pump 18 with the APC valve 17 kept open, and the HCDS gas remaining in the process chamber 6 and unreacted or after forming the layer 1 is exhausted from the process chamber 6. Further, the N2 gas supplied while the valves 14 and 26 are kept open purges the gas supply pipe 9, the inside of the reaction tube 4, and the furnace opening.

[ step 3: reaction gas supply step ]: s9043

In step 3, NH is supplied to the wafer 7 in the processing chamber 6₃A gas. The opening and closing control of the valves 11, 14 is performed in the same procedure as the opening and closing control of the valves 11, 14 in step 1. NH (NH)₃Gas and N₂The gas is supplied into the processing chamber 6 through the nozzle chamber 42 and exhausted from the exhaust pipe 15 while the flow rates of the gases are adjusted by the MFCs 10 and 13, respectively. NH supplied to wafer 7₃The gas reacts with at least a portion of the 1 st layer, i.e., the Si-containing layer, formed on the wafer 7 in step 1. Thereby, the 1 st layer is nitrided and changed (modified) to a silicon nitride layer (SiN layer) which is a 2 nd layer containing Si and N.

[ step 4: reaction gas exhaust step ]: s9044

After the formation of layer 2, the valve 11 is closed to make NH₃The supply of gas is stopped. Then, in the same process step as step 1, the NH3 gas and reaction by-products remaining in the process chamber 6 and remaining unreacted or after forming the 2 nd layer are exhausted from the process chamber 6.

By performing a cycle of the above 4 steps S9041 to S9044 a predetermined number of times (n times) so as not to overlap, a SiN film having a predetermined composition and a predetermined film thickness can be formed on the wafer 7 (S9045).

As the above-described film forming step: the processing conditions of the sequence of steps S9041 to S9044 in S904 can be exemplified as follows:

process temperature (wafer temperature): at 250-700 deg.C,

Process pressure (pressure in process chamber): 1 to 4000Pa,

HCDS gas supply flow rate: 1 to 2000sccm,

NH₃Gas supply flow rate: 100 to 10000sccm,

N₂Gas supply flow rate (nozzle): 100 to 10000sccm,

N₂Gas supply flow rate (rotation axis): 100 to 500 sccm.

By setting each process condition to a value within each range, the film formation process can be appropriately performed.

A thermally decomposable gas such as HCDS may easily form a film of a by-product on the surface of a metal compared to quartz. SiO, SiON, etc. are easily adhered to the surface exposed to HCDS (and ammonia gas), particularly at 260 ℃ or lower.

(purge and atmospheric recovery): s905

After the film formation process is completed, the valve 14 is opened to supply N into the process chamber 6 from the gas supply pipe 12₂And gas is discharged from the exhaust pipe 15. Thereby, the ambient gas in the processing chamber 6 is replaced with an inert gas (inert gas replacement), and the remaining raw materials and by-products are removed (purged) from the processing chamber 6. Thereafter, the APC valve 17 is closed, and N is filled₂The gas is discharged until the pressure in the processing chamber 6 becomes atmospheric (atmospheric pressure recovery).

(boat unloading and wafer taking out): s906

The sealing lid 19 is lowered by the boat elevator 27, and the lower end of the manifold 5 is opened. The processed wafers 7 are carried out from the lower end of the manifold 5 to the outside of the reaction tube 4 while being supported by the boat 21 (boat unloading). The processed wafer 7 is taken out from the boat 21.

By performing the above-described film formation process, a thin film can be formed by depositing a SiN film containing nitrogen on the surface of the member in the heated reaction tube 4, for example, the inner wall of the outer tube 4A, the surface of the nozzle 8, the surface of the inner tube 4B, the surface of the boat 21, or the like. Therefore, when the accumulated film thickness, which is the amount of the deposit, reaches a predetermined amount (thickness) before the deposit peels off or falls, the cleaning process is performed. The cleaning treatment is performed by supplying a fluorine-based gas (for example, F) into the reaction tube 4₂Gas) is performed.

(temperature reduction step): s907

When the substrate holder 127 is completely carried out of the transfer chamber 124, the temperature of the wafer 7 is lowered (cooled) in the transfer chamber 124 until the wafer 7 reaches a predetermined temperature. At this time, the gas is continuously supplied from the cleaning unit 162 at the 1 st flow rate and the 1 st flow rate, and the gas is supplied from the gas pipe 176 to the substrate holder 127 at the 3 rd flow rate which is greater than the 1 st flow rate and the 3 rd flow rate which is less than the 1 st flow rate and greater than the 2 nd flow rate. Here, the predetermined temperature is a temperature at which the wafer 7 can be carried out, and is equal to or lower than the heat-resistant temperature of the tweezers 156a or the wafer cassette 160.

The No. 3 flow rate is, for example, 20 to 40cm/s, and the No. 3 flow rate is, for example, 15 to 70L/min. When the 3 rd flow rate is less than 20cm/s or the 3 rd flow rate is less than 15L/min, a horizontal gas flow cannot be formed in the region between the lowermost wafer 7 of the wafer boat 21 and the heat shield 144. The wafer 7 is vibrated at a flow rate of greater than 40cm/s at the 3 rd flow rate or greater than 70L/min at the 3 rd flow rate.

In the above-described film formation process, a thin film can be formed by depositing a SiN film containing nitrogen on the surface of the member in the heated reaction tube 4, for example, the inner wall of the outer tube 4A, the surface of the nozzle 8, the surface of the inner tube 4B, the surface of the boat 21, or the like. Therefore, when the amount of these deposits, that is, the cumulative film thickness reaches a predetermined amount (thickness) before the deposits are peeled off or dropped, the cleaning process is performed. The cleaning treatment is performed by supplying a fluorine-based gas (for example, F) into the reaction tube 4₂Gas) is performed.

When the boat is unloaded, the wafers 7, the boat 21, and the heat insulating members are cooled by the cooling gas. In this case, if the dummy substrate is exposed to a strong gas flow, the film may be peeled off due to rapid cooling, and particles may be generated.

[ management for continuous use of Si fire dummy ]

The Si meltallizing dummy wafer 820 gradually blocks pores due to SiN or the like after film formation, and the surface area decreases. In the wafer boat 21 on which N wafers can be mounted, when the respective mounting positions are set to Slot N, Slot N-1, Slot N-2, and … … from the uppermost side, for example, wafers whose number of uses is N or less are mounted on the Slot N, wafers whose number of uses is N +1 or more and 2N or less are mounted on the Slot N-1, wafers whose number of uses is 2N +1 or more and 3N or less are mounted on the Slot N-2, and wafers whose number of uses is i × N +1 or more and (i +1) × N or less are mounted on the Slot N-i. Here, n is the number of times that the tape can be repeatedly used while being held at 1 mounting position, and i is an index from 0.

If the number of the Si thermal spraying dummy wafers 820 on the upper side of the wafer boat 21 is set to 4, when the wafer boat descends and the Si thermal spraying dummy wafer 820 whose number of use times reaches 4N is located in the Slot N-3, the transfer machine takes out the Si thermal spraying dummy wafer 820 from the wafer boat 21 and transfers the Si thermal spraying dummy wafer 820 to a predetermined container, and the Si thermal spraying dummy wafers 820 located in the Slot N to the Slot N-2 are transferred to the next-stage Slot N-1 to Slot N-3, respectively. Then, a new Si fuse dummy wafer 820 is mounted on the Slot N.

The same applies to the Si-fired dummy wafer 820 on the lower side of the boat 21. Further, the portion where the number of uses or the reduction in surface area is equal to or more than a predetermined value may be set as a sub dummy wafer, and the Si thermal spraying dummy wafer 820 may be divided into a dummy wafer and a sub dummy wafer to be subjected to grouping management.

Here, the Si-fired dummy wafer 820 having a smaller number of times of use is disposed farther from the production wafer 810, but conversely, the Si-fired dummy wafer 820 having a smaller number of times of use may be disposed closer to the production wafer 810.

[ method for regenerating Si sputter dummy wafer ]

Remelting injection

Like a normal recycled wafer, the Si sprayed dummy wafer 820 is once polished by a method such as CMP to remove the Si sprayed film 822. Alternatively, a thick film of, for example, polycrystalline or single crystal Si is formed on the Si sintered film 822 so as to substantially close the opening of the pore. Thereafter, Si meltblowing was performed.

Dry cleaning

The regeneration can be performed by a method of selectively etching a material formed on the Si sprayed film 822 of the Si sprayed dummy wafer 820. For example, in the case of SiN/Si, isotropic plasma etching using a fluorine-containing olefin (hydrofluorocarbon) can be employed.

Wet cleaning

The regeneration can be performed by a method of selectively etching a material formed on the Si sprayed film 822 of the Si sprayed dummy wafer 820. For example, in the case of SiN/Si, phosphoric acid etching can be used.

According to the present embodiment, the load effect during the processing of a large-consumable wafer can be alleviated, and the inter-surface uniformity of the film formed on the production wafer among a plurality of production wafers can be improved.

Example 2

While in example 1 the Si-fired dummy wafer is prepared by Si-firing a front surface of a bare wafer having the same size as that of a production wafer, a second example is shown in fig. 11 in which a bare wafer having a diameter smaller than that of a production wafer is used and a plurality of Si-fired dummy wafers 1102 formed on the small-diameter bare wafer by Si-firing are mounted on a tray 1101.

The configuration of the substrate processing apparatus is the same as that described in embodiment 1 using fig. 1 to 9, and therefore, the description thereof is omitted.

Instead of the Si-fired dummy wafers 820 described in example 1, the tray 1101 (made of any material, for example, quartz, SiC, or the like) is mounted on the boat 21. In this case, the surface area of the appearance on the tray 1101 can be adjusted by changing the number of the mounted Si thermal spraying dummy wafers 1102 instead of the thermal spraying film thickness.

According to the present embodiment, the load effect during the processing of a large-consumable wafer can be alleviated, and the inter-surface uniformity between a plurality of production wafers of a film formed on the production wafer can be improved.

Industrial applicability

The present disclosure relates to a substrate processing apparatus and a substrate processing method, which can be applied to the field of manufacturing semiconductor components in which a semiconductor substrate is heat-treated to form a thin film on a surface thereof.

Description of the reference numerals

1 substrate processing apparatus

2 treatment furnace

3 heating device

4 reaction tube

8 spray nozzle

19 sealing cover

21. 126 boat

27. 132 boat elevator

29 controller

124 transfer chamber

134 gas supply mechanism

162 cleaning unit

402 particle counter

820 Si fire dummy wafer.