Protective plate, substrate processing apparatus, and method of manufacturing semiconductor device

There is provided a technique that includes a protective plate installed on a lid, including: a disc portion, of which a lower surface is in contact with an upper surface of the lid, a side wall portion extending from an outer peripheral end of the disc portion, a groove formed in the lower surface of the disc portion, and a stepped portion formed to be closer to the outer peripheral end of the disc portion than the groove, a clearance formed between the upper surface of the lid and the stepped portion, wherein the groove is configured to be able to form a flow of a gas that runs through a gap between the lid and the stepped portion, and is supplied to an outside of the side wall portion.

TECHNICAL FIELD

The present disclosure relates to a protective plate used for a process such as forming a thin film or the like on a substrate, a substrate processing apparatus, and a method of manufacturing a semiconductor device.

BACKGROUND

There is a vertical substrate processing apparatus as a substrate processing apparatus that performs substrate processing in a process of manufacturing a semiconductor device. In the vertical substrate processing apparatus, a plurality of substrates are stacked and held in multiple stages, loaded into a process chamber, and processed at once.

During the processing, a furnace port at the lower portion of the process chamber can be the coldest in the process chamber. When a precursor gas diffuses to the furnace port, reaction by-products of the precursor gas adhere to the furnace port, which may cause a generation of particles. There has been conventionally proposed a substrate processing apparatus that supplies a purge gas to a furnace port having a high process gas concentration so as to suppress adhesion of by-products to metal parts.

However, in some types of substrate processing apparatuses, a dilution of the precursor gas is insufficient due to a configuration of the furnace port, and by-products by the precursor gas may adhere to the furnace port. In particular, when metal parts are used in the furnace port, by-products tend to adhere to the metal parts. For this reason, even as cleanings are performed more frequently, particles may be generated.

SUMMARY

The present disclosure provides some embodiments of a protective plate, a substrate processing apparatus, and a method of manufacturing a semiconductor device, which are capable of suppressing adhesion of by-products by a precursor gas to a furnace port.

According to one or more embodiments of the present disclosure, there is provided a technique that includes a protective plate installed on a lid including: a disc portion having a disc shape, wherein at least a part of a lower surface of the disc portion is in contact with an upper surface of the lid, a side wall portion extending vertically from an outer peripheral end of the disc portion, a groove having a loop shape and formed in the lower surface of the disc portion, and a stepped portion formed to be closer to the outer peripheral end of the disc portion than the groove, a predetermined clearance being formed between the upper surface of the lid and the stepped portion, wherein the groove is configured to be able to form a flow of a gas that runs through a gap between the lid and the stepped portion, and is supplied to an outside of the side wall portion.

DETAILED DESCRIPTION

Embodiments of the present disclosure will now be described with reference to the drawings. Throughout the drawings, the same or corresponding components are denoted by the same or corresponding reference numerals, and explanation thereof may be omitted.

First embodiments may include a substrate processing apparatus which is a vertical substrate processing apparatus (hereinafter referred to as a “processing apparatus”)1that performs a substrate processing process such as heat treatment or the like as a manufacturing process in a method of manufacturing a semiconductor device.

As shown inFIG. 1, the processing apparatus1includes a reaction tube2having a cylindrical shape and a heater3as a heating mechanism (heating means) installed on the outer periphery of the reaction tube2. The reaction tube2is made of, for example, quartz (SiO), silicon carbide (SiC), or the like. A temperature detector4is installed in the reaction tube2. The temperature detector4is erected along the inner wall of the reaction tube2.

A manifold5having a cylindrical shape is connected to the lower end opening of the reaction tube2via a seal member6such as an O-ring or the like so as to support the lower end of the reaction tube2. The manifold5is made of metal such as stainless steel or the like. A process vessel7is formed by the reaction tube2and the manifold5. A process chamber8in which wafers W as substrates are processed is formed inside the process vessel7.

In addition, the reaction tube2is formed with a supply buffer chamber2A and an exhaust buffer chamber2B facing each other so as to protrude outward (in the radial direction). The supply buffer chamber2A and the exhaust buffer chamber2B are partitioned into a plurality of spaces by partition walls. A nozzle23a, a nozzle23b, and a nozzle23c(which will be described later) are installed in the respective spaces of the supply buffer chamber2A. A boundary wall between the supply buffer chamber2A and the exhaust buffer chamber2B and the process chamber8is formed to have the same inner diameter as the inner diameter of the reaction tube at a location where the supply buffer chamber2A and so on are not installed, and a plurality of slits in fluid communication with both sides are installed. An opening2E for inserting or removing the nozzle23a, the nozzle23b, and the nozzle23cis formed in a lower portion of the inner wall of the supply buffer chamber2A. The opening2E is formed to have substantially the same width as the supply buffer chamber2A. Here, since it is difficult to eliminate the gaps between the opening2E and the bases of the nozzle23a, the nozzle23band the nozzle23c, it is difficult to prevent a reaction gas or the like from flowing out of the gaps.

The lower end opening of the manifold5(the lower end opening of the process vessel7) is opened/closed by a lid9having a disc shape. The lid9is made of, for example, metal. A seal member11such as an O-ring or the like is installed on the upper surface of the lid9, and the reaction tube2is hermetically sealed from the outside air by the seal member11. A protective plate12as a lid cover to be described later is installed on the upper surface of the lid9. A hole is formed in the center of the lid9, and a rotary shaft13to be described later is inserted through the hole. In order to protect the seal member6and the seal member11, they may be kept at 200 degrees C. or less, and a water jacket (not shown) can be attached to the flanges of the reaction tube2or the manifold5.

The process chamber8stores therein a boat14as a substrate holder for supporting a plurality of wafers W, for example, 25 to 150 wafers W, vertically in a shelf shape. The boat14is made of, for example, quartz, SiC, or the like, and is supported above a heat-insulating structure15.

The heat-insulating structure15has an outer shape of cylinder with a generally flat bottom and is supported by the rotary shaft13that penetrates the lid9. The rotary shaft13is connected to a rotation mechanism16installed below the lid9. For example, a magnetic fluid seal is installed at a portion of the rotary shaft13that penetrates the lid9, and the rotary shaft13is configured to be rotatable in a state where the interior of the reaction tube2is hermetically sealed. When the rotary shaft13is rotated, the heat-insulating structure15and the boat14are rotated together. The lid9is driven in the vertical direction by a boat elevator17as an elevator. The substrate holder and the lid9are integrally moved up or down by the boat elevator17, so that the boat14is loaded/unloaded into/from the reaction tube2.

The processing apparatus1includes a gas supply mechanism18that supplies a precursor gas as a process gas to be used for substrate processing, a reaction gas, and an inert gas into the process chamber8. The process gas supplied by the gas supply mechanism18is selected according to the type of a film to be formed. In the first embodiments, the gas supply mechanism18includes a precursor gas supplier, a reaction gas supplier, an inert gas supplier, a first purge gas supplier, and a second purge gas supplier.

The precursor gas supplier includes a gas supply pipe19a. A mass flow controller (MFC)21a, which is a flow rate controller (flow rate control part), and a valve22a, which is an opening/closing valve, are installed in the gas supply pipe19ain order from an upstream direction. A downstream end of the gas supply pipe19ais connected to the nozzle23athat penetrates the side wall of the manifold5. The nozzle23ais vertically installed in the reaction tube2along the inner wall of the reaction tube2, and has a plurality of supply holes formed to open toward the wafers W held by the boat14. A precursor gas is supplied to the wafers W through the supply holes of the nozzle23a.

Hereinafter, with the same configuration, a reaction gas is supplied to the wafers W from the reaction gas supplier via a gas supply pipe19b, an MFC21b, a valve22b, and the nozzle23b. An inert gas is supplied to the wafers W from the inert gas supplier via gas supply pipes19c,19dand19e, MFCs21c,21dand21e, valves22c,22dand22e, and the nozzles23a,23band23c.

The first purge gas supplier (supply mechanism) includes a gas supply pipe19f. An MFC21fand a valve22fare installed in the gas supply pipe19fin order from an upstream direction. A downstream end of the gas supply pipe19fis connected to a hollow portion24formed around the rotary shaft13. The hollow portion24is sealed in front of a bearing by a magnetic fluid seal, and is opened to the upper end, that is, to the interior of the reaction tube2. In addition, a space communicating from the hollow portion24to the upper surface of the protective plate12is formed, and the space is continuous with a gap41(which will be described, seeFIG. 2) formed between the heat-insulating structure15and the protective plate12and forms a first purge gas flow path25(seeFIG. 2).

The second purge gas supplier (supply mechanism) includes a gas supply pipe19g. An MFC21gand a valve22gare installed in the gas supply pipe19gin order from an upstream direction. A downstream end of the gas supply pipe19gpenetrates the lid9, and a second purge gas supply port is formed on the upper surface of the lid9. Accordingly, the second purge gas supply port is formed on the upper surface of the lid9and opens to a second purge gas flow path27. The opening position of the second purge gas supply port is in the vicinity of the nozzles23a,23band23c(seeFIG. 3B). A flexible pipe such as a bellows pipe is used for the gas supply pipe19abetween the valve22gand the second purge gas supply port. The second purge gas flow path27has substantially an annular shape (loop shape) and is formed over the entire circumference of the lower surface of the protective plate12.

An exhaust pipe32is attached to an exhaust port26of the manifold5. A vacuum pump35, which is a vacuum exhaust device, is connected to the exhaust pipe32via a pressure sensor33, which is a pressure detector (pressure detection part) for detecting the internal pressure of the process chamber8, and an APC (Auto Pressure Controller) valve34which is a pressure regulator (pressure regulation part). With this configuration, the internal pressure of the process chamber8can be set to a processing pressure corresponding to the processing. The exhaust pipe32is installed at a position facing the nozzles23a,23b, and23c.

The rotation mechanism16, the boat elevator17, and the MFCs21ato21g, valves22ato22gand APC valve34of the gas supply mechanism18are connected to a controller36for controlling them. The controller36includes, for example, a microprocessor (computer) including a CPU, and is configured to control the operation of the processing apparatus1. For example, an input/output device37configured as a touch panel or the like is connected to the controller36.

A storage device38, which is a storage medium, is connected to the controller36. The storage device38stores, in a readable manner, a control program for controlling the operation of the processing apparatus1, and a program (also referred to as a recipe) that causes each component of the processing apparatus1to execute a process in accordance with processing conditions.

The storage device38may be a memory device (hard disk or flash memory) built in the controller36, or a portable external recording device (a magnetic tape, a magnetic disk such as a flexible disk or a hard disk, an optical disk such as a CD or DVD, a magneto-optical disk such as an MO, or a semiconductor memory such as a USB memory or a memory card). Further, the program may be provided to the computer using a communication means such as the Internet or a dedicated line. The program is read from the storage device38according to an instruction or the like from the input/output device37as necessary, and the controller36executes a process according to the read recipe to cause the processing apparatus1to execute a desired process under control of the controller36.

The protective plate12installed on the upper surface of the lid9is made of a heat-resistant and corrosion-resistant material such as quartz or the like. When the protective plate12covers the metal lid9, the contact of a process gas to the lid9is suppressed, and corrosion and deterioration of the lid9due to the process gas are accordingly suppressed.

FIG. 2shows the internal structure of a furnace port and the heat-insulating structure15. The heat-insulating structure15includes a cylindrical body39having a columnar shape and a bottom plate40made of metal and having a disc shape supported by the rotary shaft13. The cylindrical body39is made of a heat-resistant material such as quartz or the like, has a hollow structure with its lower end opened, and is placed on the bottom plate40. In addition, a heat-insulating plate support pillar42having a hollow cylindrical shape is installed on the bottom plate40in the cylindrical body39.

The heat-insulating plate support pillar42holds disc-shaped heat-insulating plates43made of a heat-resistant material such as quartz or the like, which are stacked in multi-stage. A sub-heater44is inserted into the heat-insulating plate support pillar42. The sub-heater44has a ring shape above the heat-insulating plate support pillar42, and the upper surface of the cylindrical body39and the lower portion of the process chamber8are heated by the sub-heater44. The rotary shaft13also has a hollow structure in order to insert the sub-heater44, and a third purge gas branched from a first purge gas is introduced into the rotary shaft13through a through hole13cinstalled in a side portion of the rotary shaft13near a magnetic seal.

After the first purge gas supplied from the first purge gas supplier ascends over the outer periphery of the rotary shaft13, the first purge gas changes its course horizontally, and is supplied to the lower portion of the process vessel7, which is the furnace port, while purging the gap41, which is narrow, between the bottom plate40and the protective plate12. That is, the first purge gas purges the periphery of the rotary shaft13in the upstream, then purges the exposed surface of the protective plate12and the bases of the nozzles23ato23cin the downstream, and finally is discharged through the exhaust port26formed at the lower end of the reaction tube2. In some embodiments, a supply path of the first purge gas supplied from the first purge gas supply mechanism may exclude a side wall portion29.

The protective plate12has a first thin portion28formed to extend to the vicinity of the manifold5except for the location where the nozzles23a,23band23care disposed. In addition, the side wall portion29extending vertically along the inner wall of the manifold5is formed at the outer peripheral end of the first thin portion28. A clearance having a predetermined interval is formed between the first thin portion28and the lid9, and a clearance31having a predetermined interval is also formed between the side wall portion29and the manifold5.

A second purge gas supplied to the second purge gas flow path27flows out from the second purge gas flow path27in the radial direction, purges the back surface of the protective plate12and the inner surface of the manifold5while passing through the clearance31, and then is discharged through the exhaust port26.

The third purge gas branched from the first purge gas in the hollow portion24is introduced into the heat-insulating structure15through a gap between the rotary shaft13and the sub-heater44and a gap between the heat-insulating plate support pillar42and the sub-heater44. These gaps form a third purge gas flow path30. In addition, as discharge holes of the third purge gas, a plurality of openings40A are formed at, for example, an equiangular pitch in the bottom plate40. The third purge gas is supplied through the third purge gas flow path30into the cylindrical body39from the upper end of the heat-insulating plate support pillar42. The third purge gas in the cylindrical body39descends along the inner peripheral surface of the cylindrical body39, is discharged through the openings40A, merges with the first purge gas, and is released into the furnace port. In the course of releasing the third purge gas into the furnace port, the interior of the cylindrical body39is purged. The conductance of each flow path is designed so that the flow rate of the third purge gas is higher than that of the first purge gas. The purge gas may be any gas that does not react with the precursor gas or the reaction gas.

Next, the concentration (partial pressure) of a process gas at the furnace port will be described.FIGS. 6A and 6Bshow a process gas concentration (gas partial pressure) distribution in a reference furnace port, that is, a furnace port for which purge with the second purge gas54(which will be described later) is not performed. As shown inFIGS. 6A and 6B, in the case of the reference configuration, it was found that the process gas concentration was high at a portion (nozzle23side) of the bases of the nozzles23ato23clocated on the opposite side (opposing side) of the exhaust port26in the furnace port. Further, it was confirmed that the adhesion of by-products was noticeable at the portion of the bases of the nozzles23ato23c.

The process gas concentration in the inner peripheral surface of the manifold5at this time was 2.5 Pa or more for the nozzle23side, and 1 Pa or less for the opposite side (exhaust port26side) of the nozzle23. That is, substantially no by-product was observed in the exhaust port26side. The temperature of the manifold is almost constant over the entire circumference, and is about 200 degrees C. Thus, when the process gas concentration in the furnace port is set to a value (for example, 1 Pa) lower than a critical value (a value between 1 and 2.5 Pa, for example, 2 Pa) at which no by-product is generated, it is thought that adhesion of by-products to the furnace port can be sufficiently suppressed.

The reason why the process gas concentration in the exhaust port26side is low is considered to be that the purge gas easily flows toward the exhaust port26. On the other hand, since it is difficult to sufficiently supply the purge gas to the nozzles23ato23cside as much as the purge gas flows to the exhaust port26, it is considered that the process gas concentration in the nozzles23ato23cside is high. Accordingly, by supplying the purge gas at a sufficient flow rate to the nozzles23ato23cside to sufficiently dilute the process gas on the nozzles23ato23cside, it is considered that the process gas concentration in the nozzle23side can have a value lower than the critical value at which no by-product is generated.

The process gas concentration in the furnace port decreases as the flow rate of the purge gas increases. However, when the flow rate of the purge gas is higher than a certain critical value (for example, higher than 500 sccm), it has been found that the purge gas of the furnace port reaches a wafer processing region, which may adversely affect a film-forming process (for example, inter-surface uniformity). In order to maintain the quality of the film-forming process, the purge gas flow rate may be 500 sccm or less. However, in this case, it has been found that the process gas concentration in the furnace port has a critical value (for example, 1 Pa) or more, and by-products may adhere to the furnace port. Here, the inter-surface uniformity means processing uniformity for each substrate. For example, this means that a substrate positioned in the lower portion of the boat14has substantially the same processing state as a substrate positioned in the upper portion of the boat14.

Therefore, the inventors have found that adhesion of by-products in the entire furnace port can be suppressed without adversely affecting the film-forming process by increasing the flow rate of the purge gas supplied to portions where the process gas concentration is high and the by-products are likely to adhere, for example, the bases and peripheral portions of the nozzle23ato23cof the furnace port, more than the other portions, that is, by increasing the flow rate of the purge gas locally. In addition, the inventors have found that adhesion of by-products can be suppressed by supplying most of the first purge gas53to the bases and peripheral portions of the nozzles23ato23cand supplying the second purge gas54to the other parts along the inner wall surface of the manifold5and by intensively supplying the purge gas to a portion where the process gas concentration is high while supplying the purge gas to the other portions, while suppressing the purge gas flow rate below a critical value.

Hereinafter, the structure of the protective plate12for intensively supplying the first purge gas53to the bases of the nozzles23ato23cand supplying the second purge gas54to the other portions will be described with reference toFIGS. 3A and 3BandFIGS. 4A and 4B. InFIGS. 3A, 3B and 4A, the flow of the first purge gas53is indicated by a solid arrow, and the flow of the second purge gas54is indicated by a broken arrow. InFIGS. 3A, 3B, 4A and 4B, the nozzles23ato23c(installation positions of the nozzles23ato23c) are shown as holes for the sake of convenience.

As shown inFIGS. 3A and 4B, a thick portion45, a first thin portion28, a second thin portion47, and a third thin portion48are formed in the surface of the protective plate12. The thick portion45has substantially a circular shape with its portion cut away, and a hole46through which the heat-insulating plate support pillar42is inserted is formed in the center portion of the thick portion45. The thick portion45, the first thin portion28, the second thin portion47, and the third thin portion48form a disc portion having a disc shape.

The first thin portion28is formed on the outer peripheral side of the thick portion45. The thickness of the first thin portion28is smaller than that of the thick portion45, and has an annular shape with its portion cut away. Further, the side wall portion29is formed continuously and perpendicularly to the outer peripheral end of the first thin portion28. A portion where the first thin portion28is cut away corresponds to the second thin portion47having a thickness smaller than that of the first thin portion28. In order to avoid contact with the nozzles23ato23c, the second thin portion47is formed at a location corresponding to its installation position (the bases of the nozzles23ato23cand their peripheral portions). The side wall portion29is not formed at the outer peripheral end of the second thin portion47.

A portion where the thick portion45is cut away corresponds to the third thin portion48having a thickness smaller than that of the thick portion45and having the same or substantially the same thickness as the first thin portion28. The third thin portion48is continuous to the inner side in the radial direction of the second thin portion47and is an arc-shaped portion that is concentric with the second thin portion47and has a predetermined width. In addition, specifically, the thickness of the third thin portion48is configured to be greater than the thickness of the second thin portion47. With this configuration, the flow path resistance from the center side of the protective plate12toward the nozzles23ato23ccan be reduced. That is, it is possible to increase the gas supply amount from the center side of the protective plate12toward the nozzles23ato23c.

In addition, the outer diameter of the bottom plate40is smaller than the outer diameter of the thick portion45, and the position of the inner peripheral end of the third thin portion48is closer to the center of the bottom plate40than the inner peripheral end of the bottom plate40. Accordingly, since the gap41larger than a gap between the bottom plate40and the thick portion45is formed between the bottom plate40and the third thin portion48, the flow path resistance is smaller in the gap41than in the gap between the bottom plate40and the thick portion45. Therefore, as shown inFIGS. 3A and 4A, most of the first purge gas53that descends along the inner peripheral surface of the cylindrical body39is supplied below the nozzles23ato23cthrough the third thin portion48to purge the bases and peripheral portions of the nozzles23ato23c.

A region formed by connecting both ends of a region where the concentration of the precursor gas and the reaction gas is high and the first purge gas53needs to flow intensively and the center of the protective plate12is a sectorial region S, and the second thin portion47and the third thin portion48are located in the sectorial region S. The central angle (open angle) a of the sectorial region S is, for example, 60° and is appropriately set within a range of 0°<α<120° according to the number of nozzles installed or the like. When the central angle α exceeds 120°, the process gas concentration may exceed the critical value, and there is a possibility that by-products may adhere to the process vessel7, which is not preferable.

The thick portion45is formed with a protruding portion49that protrudes radially outward from the boundary with the third thin portion48(the inner peripheral end of the third thin portion48) to the outer peripheral end of the third thin portion48. The position where the protruding portion49is formed is, for example, a position facing the exhaust port26(the opposite side of the exhaust port26). A height of the upper surface of the protruding portion49is the same as a height of the inside of the thin portion.

As shown inFIG. 3B, a groove27having a predetermined width and a predetermined depth (hereinafter referred to as a “second purge gas flow path”) is engraved in the back surfaces of the thick portion45and the protruding portion49along the outer peripheral ends of the thick portion45and the protruding portion49. The second purge gas flow path27includes a first flow path27aextending from the distal end of the protruding portion49in the central direction, a second flow path27bthat branches from the proximal end of the protruding portion49, is curved in the circumferential direction and extends along the inner peripheral end of the third thin portion48, and a third flow path27chaving an annular shape that is curved outward in the side end of the third thin portion48in the radial direction, is further curved in the circumferential direction along the outer peripheral end of the thick portion45, extends along the outer peripheral end of the thick portion45and is continuous with the second flow path27b.

A stepped portion52having a decreasing thickness is formed on the back surface of the protective plate12on the outer peripheral side (the back surfaces of the first thin portion28, the second thin portion47and the third thin portion48) of the second purge gas flow path27. Further, the stepped portion52is formed to be closer to the outer peripheral end of the disc portion than the groove27. Accordingly, when the protective plate12is installed on the lid9, a central portion51(the back surface of the thick portion45) closer to the center side than the second purge gas flow path27and the upper surface of the lid9are in contact with each other, and a slight clearance is formed between the upper surface of the lid9and the stepped portion52.

The gas supply pipe19gof the second purge gas supplier is in fluid communication with the distal end (outer peripheral side) of the first flow path27a, and the second purge gas54is supplied from the distal end of the first flow path27a. The second purge gas54supplied to the first flow path27asequentially flows in the order of the first flow path27a, the second flow path27b, and the third flow path27c. In this operation, the upper surface of the lid9and the central portion51are in contact with each other, and a slight clearance is formed between the upper surface of the lid9and the stepped portion52. Accordingly, the second purge gas54flows out of the clearance in the course of flowing through the first flow path27a, the second flow path27b, and the third flow path27c, flows between the upper surface of the lid9and the stepped portion52and between the inner peripheral surface of the manifold5and the side wall portion29, and is released to the furnace port while purging. The second purge gas54released to the furnace port is exhausted through the exhaust port26.

In addition, the clearance that communicates the first flow path27a, the second flow path27b, and the third flow path27cto the furnace port has a constant interval on the entire circumference, and allows the purge gas to flow out to the furnace port relatively uniformly in at least the third flow path27c. On the other hand, in the second flow path27b, since the clearance length is approximately doubled and the conductance is reduced, the outflow is small. Since the amount of increase of the first purge gas by the third thin portion48is larger than the amount of decrease of the outflow, the purge gas supply to the bases of the nozzles23ato23ccan be enhanced as a result.

FIG. 5shows the flow state of the second purge gas54with flow lines when the second purge gas54is supplied to the second purge gas flow path27. As shown inFIG. 5, the second purge gas54hardly flows out from the first flow path27aand the second flow path27b, flows through the third flow path27cwhile flowing out outward in the radial direction, and purges a space between the manifold5and the side wall portion29. Strictly speaking, the amount of outflow of the second purge gas54increases as it approaches the nozzles23ato23c, and decreases as it approaches the exhaust port26. Although it is shown inFIG. 5that there is no flux of the second purge gas54in the vicinity of the exhaust port26, a small amount of second purge gas54actually flows.

FIGS. 7A and 7Bshow the process gas concentration (gas partial pressure) distribution in the furnace port in the structure for intensively supplying the first purge gas53to the bases of the nozzles23ato23cand supplying the second purge gas54to the other portions, according to the first embodiments. As shown inFIGS. 7A and 7B, in the case of the configuration of the first embodiments, it can be seen that the process gas concentration in the furnace port is reduced over the entire region, and in particular, the process gas concentration is remarkably reduced in the bases and peripheral portions (the vicinity of a first measurement point and a second measurement point) of the nozzles23ato23c.

FIG. 8is a graph showing a comparison between results of measurement on gas partial pressure at the first to seventh measurement points shown inFIGS. 6B and 7B. InFIG. 8, a solid line indicates the process gas concentration distribution of the reference structure, and a broken line indicates the process gas concentration distribution of the structure of the first embodiments.

As can be seen fromFIG. 8, in the structure of the first embodiments, in the bases and peripheral portions (the vicinity of the first measurement point and the second measurement point) of the nozzles23ato23cto which the first purge gas53is intensively supplied, the process gas concentration is reduced to about ½ of that in the reference structure. As can be further seen, in the portions (the third to seventh measurement points) where the side wall portion29is formed and the second purge gas54is supplied between the side wall portion29and the manifold5through the second purge gas flow path27, the process gas concentration is reduced to ¼ or less of that in the reference structure.

Next, a process of forming a film on a substrate using the above-described processing apparatus1(film-forming process) will be described. Here, examples of forming a silicon oxide (SiO2) film on wafers W by supplying a DCS (SiH2Cl2: dichlorosilane) gas as a precursor gas and an O2(oxygen) gas as a reaction gas to the wafers W will be described. In the following description, the operation of each of the parts constituting the processing apparatus1is controlled by the controller36.

(Wafer Charging and Boat Loading)

When a plurality of wafers W are charged into the boat14(wafer charging), the boat14is loaded into the process chamber8by the boat elevator17(boat loading), and the lower portion of the reaction tube2is hermetically closed (sealed) by the lid9. In this operation, a N2gas as the first purge gas53is supplied from the first purge gas supplier to the bases of the nozzles23ato23cthrough the gap41. Further, a N2gas as the second purge gas54is supplied from the second purge gas supplier between the side wall portion29and the manifold5through the second purge gas flow path27. The supply of the first purge gas53and the second purge gas54is continued at least until the film-forming process is completed.

(Pressure Adjusting and Temperature Adjusting)

The process chamber8is vacuum-exhausted (depressurization-exhausted) by the vacuum pump35so that the internal pressure of the process chamber8reaches a predetermined pressure (degree of vacuum). The internal pressure of the process chamber8is measured by the pressure sensor33, and the APC valve34is feedback-controlled based on the measured pressure information. Further, the wafers W in the process chamber8are heated by the heater3so as to reach a predetermined temperature. In this operation, the supply of power to the heater3is feedback-controlled based on the temperature information detected by the temperature detector4so that the process chamber8has a predetermined temperature distribution. Further, the rotation of the boat14and the wafers W by the rotation mechanism16is started.

When the internal temperature of the process chamber8is stabilized at a preset processing temperature, the DCS gas is supplied to the wafers W in the process chamber8. A DCS gas is controlled so as to have a desired flow rate by the MFC21a, and is supplied into the process chamber8through the gas supply pipe19aand the nozzle23a. In this operation, a N2gas is supplied from the first purge gas supplier and the second purge gas supplier to the furnace port. As a result, the bases and peripheral portions of the nozzles23ato23ccan be intensively purged with the first purge gas53, and the other portions can be purged with the second purge gas54, to dilute the precursor gas concentration in the furnace port. In this operation, the supply of N2gas by the first purge gas supplier and the second purge gas supplier may be temporarily increased.

Next, the supply of DCS gas is stopped, and the interior of the process chamber8is vacuum-exhausted by the vacuum pump35. In this operation, a N2gas as an inert gas may be supplied from the inert gas supplier into the process chamber8(inert gas purge).

Next, an O2gas is supplied to the wafers W in the process chamber8. The O2gas is controlled to have a desired flow rate by the MFC21b, and is supplied into the process chamber8through the gas supply pipe19band the nozzle23b. In this operation, a N2gas is supplied from the first purge gas supplier and the second purge gas supplier to the furnace port. As a result, the bases and peripheral portions of the nozzles23ato23ccan be purged intensively, and other portions can also be purged, to dilute the reaction gas concentration in the furnace port.

Next, the supply of O2gas is stopped, and the interior of the process chamber8is vacuum-exhausted by the vacuum pump35. In this operation, a N2gas may be supplied from the inert gas supplier into the process chamber8(inert gas purge).

By performing a cycle of performing the above-described four steps a predetermined number of times (once or more), a SiO2film having a predetermined composition and a predetermined film thickness can be formed on each of the wafers W.

After the film having the predetermined film thickness is formed, a N2gas is supplied from the inert gas supplier to replace the interior of the process chamber8with the N2gas, and the internal pressure of the process chamber8is returned to the normal pressure. Thereafter, the lid9is lowered by the boat elevator17and the boat14is unloaded from the reaction tube2(boat unloading). Thereafter, the processed wafers W are taken out from the boat14(wafer discharging).

The processing conditions for forming the SiO2film on the wafers W may be exemplified as follows.

By setting the respective processing conditions to values within the respective ranges, the film-forming process can be appropriately advanced.

As described above, in the first embodiments, the third thin portion48is formed in the portion of the thick portion45facing the nozzles23ato23c, and the second thin portion47is formed in the bases and peripheral portions of the nozzles23ato23cof the first thin portion28.

Accordingly, the gap41formed between the heat-insulating structure15and the protective plate12has a large opening area in the direction from the center of the protective plate12toward the nozzles23ato23c. That is, since the flow path resistance when passing through the gap41is reduced, most of the first purge gas53in the heat-insulating structure15passes through the third thin portion48. In addition, since the second thin portion47is thinner than the first thin portion28, the first purge gas53that has passed through the third thin portion48is supplied to the bases and peripheral portions of the nozzles23ato23cwithout spreading in the circumferential direction.

Accordingly, the process gas concentration in the bases and peripheral portions of the nozzles23ato23ccan be reduced to suppress adhesion of by-products. As a result, it is possible to suppress generation of particles and thus improve productivity.

In the first embodiments, the protective plate12is disposed in a manner such that the second purge gas flow path27is formed in the back surface of the protective plate12, the side wall portion29erected vertically is formed at the outer peripheral end of the protective plate12, and predetermined gaps are formed between the protective plate12and the lid9and between the side wall portion29and the manifold5.

Accordingly, the second purge gas54supplied to the second purge gas flow path27is released to the furnace port through the gaps between the protective plate12and the lid9and between the side wall portion29and the manifold5. By forming the side wall portion29, since the flow path sectional area of the second purge gas54can be reduced, the inner peripheral surface of the manifold5can be sufficiently purged while suppressing the supply amount of the second purge gas54, and the process gas concentration can be greatly reduced. As a result, it is possible to suppress adhesion of by-products to the inner peripheral surface of the manifold5and generation of particles and thus improve productivity.

In addition, since the supply amount of the second purge gas54can be suppressed, it is not necessary to increase the total flow rate of the purge gas more than necessary. Accordingly, it is possible to suppress an adverse effect on the wafer processing due to the purge gas and thus improve the quality of film formation.

Further, since the second purge gas54is supplied from the first flow path27aprotruding toward the nozzles23ato23c, the amount of outflow of the second purge gas54from the second purge gas flow path27increases as it approaches the nozzles23ato23cside (seeFIG. 5). That is, since a larger amount of the second purge gas54is supplied to the nozzles23ato23cside having a higher process gas concentration, the second purge gas54can be efficiently supplied in accordance with the process gas concentration distribution.

The embodiments of the present disclosure have been specifically described above. However, the present disclosure is not limited to the above-described embodiments, but various modifications can be made without departing from the gist of the present disclosure.

Next, second embodiments of the present disclosure will be described with reference toFIGS. 9A to 9C. The second embodiments may include installing the temperature detector4through the lid9and the protective plate12from below.

When installing the temperature detector4from below, as shown inFIG. 9B, the installation position of the temperature detector4is in the second purge gas flow path27(third flow path27c) formed in the back surface of the protective plate12.

Therefore, in the second embodiments, a detour flow path27dis formed by bending the third flow path27cin a semicircular shape so as to detour the temperature detector4from the center side. An introduction hole of the temperature detector4installed in the lid9may be purged in order to maintain the sealing performance. The introduction hole is in fluid communication with the detour flow path27d, and when the second purge gas54flows through the detour flow path27d, the periphery of the introduction hole can be purged.

In the second embodiments, as in the first embodiments, the first purge gas53can be intensively supplied to the bases and peripheral portions of the nozzles23ato23c, and the second purge gas54flowing out from the third flow path27ccan purge the gaps between the lid9and the stepped portion52and between the manifold5and the side wall portion29.

In the first and second embodiments, the second purge gas flow path (second flow path27b) is formed so as to avoid the third thin portion48. However, if a sufficient thickness can be secured in the third thin portion48, the second purge gas flow path may be formed in a circular shape with a certain radius without avoiding the third thin portion48.

The examples in which the DCS gas is used as the precursor gas have been described in the above-described first and second embodiments. However, the present disclosure is not limited to such embodiments. For example, as the precursor gas, it may be possible to use, for example, an inorganic halosilane precursor gas such as a HCDS (Si2Cl6: hexachlorodisilane) gas, a MCS (SiH3Cl: monochlorosilane) gas or a TCS (SiHCl3: trichlorosilane) gas, or the like, a halogen-group-free amino-based (amine-based) silane precursor gas such as a 3DMAS (Si[N(CH3)2]3H: trisdimethylaminosilane) gas or a BTBAS (SiH2[NH(C4H9)]2: bistertiarybutylaminosilane) gas, or the like, or a halogen-group-free inorganic silane precursor gas such as a MS (SiH4: monosilane) gas or a DS (Si2H6: disilane) gas, or the like, as well as the DCS gas.

The examples in which the SiO2film is formed have been described in the above-described embodiments. However, the present disclosure is not limited to such embodiments. Alternatively or in addition to these, they may be possible to form, for example, a SiN film, a SiON film, a SiOCN film, a SiOC film, a SiCN film, a SiBN film, or a SiBCN film, or the like using a nitrogen (N)-containing gas (nitriding gas) such as an ammonia (NH3) gas or the like, a carbon (C)-containing gas such as a propylene (C3H6) gas or the like, or a boron (B)-containing gas such as a boron trichloride (BCl3) gas or the like. Even when these films are formed, the film formation can be performed under the same processing conditions as in the above-described embodiments, and the same effects as in the above-described embodiments can be obtained.

The present disclosure can be suitably applied to cases of forming a film which contains metal element such as titanium (Ti), zirconium (Zr), hafnium (Hf), tantalum (Ta), niobium (Nb), aluminum (Al), molybdenum (Mo), tungsten (W), or the like, that is, a metal-based film, on a wafer W.

The present disclosure can be applied to an apparatus for processing a semiconductor substrate or the like under reduced pressure, process gas atmosphere or high temperature, and can be applied to, for example, deposition such as CVD, PVD, ALD, epitaxial growth, or the like, a process for forming an oxide film or a nitride film on a surface, a diffusion process or an etching process.

According to the present disclosure in some embodiments, it is possible to suppress adhesion of by-products and generation of particles and thus improve productivity.