SUBSTRATE PROCESSING APPARATUS

A substrate processing apparatus includes: an inner cylinder having a first region formed inside the inner cylinder to accommodate a substrate; an outer cylinder provided outside the inner cylinder with a second region interposed between the inner cylinder and the outer cylinder and including an exhaust port formed in an end portion of a sidewall of the outer cylinder; a nozzle configured to discharge a gas to the first region; and a gas flow regulator including a plurality of slits provided from an upstream side toward a downstream side in a flow direction of the gas in a flow path of the gas from the first region to the exhaust port.

CROSS-REFERENCE TO RELATED APPLICATION

This application is based upon and claims the benefit of priority from Japanese Patent Application No. 2022-071477, filed on Apr. 25, 2022, the entire contents of which are incorporated herein by reference.

TECHNICAL FIELD

The present disclosure relates to a substrate processing apparatus.

BACKGROUND

In a substrate processing apparatus provided with a processing container including an inner cylinder and an outer cylinder which are arranged concentrically, a configuration in which a plate-shaped rectifying plate is provided between the inner cylinder and the outer cylinder has been known (see Patent Document 1, for example).

Prior Art Document

SUMMARY

According to one embodiment of the present disclosure, there is provided a substrate processing apparatus including: an inner cylinder having a first region formed inside the inner cylinder to accommodate a substrate; an outer cylinder provided outside the inner cylinder with a second region interposed between the inner cylinder and the outer cylinder and including an exhaust port formed in an end portion of a sidewall of the outer cylinder; a nozzle configured to discharge a gas to the first region; and a gas flow regulator including a plurality of slits provided from an upstream side toward a downstream side in a flow direction of the gas in a flow path of the gas from the first region to the exhaust port.

DETAILED DESCRIPTION

Hereinafter, non-limiting exemplary embodiments of the present disclosure will be described with reference to the accompanying drawings. In all the accompanying drawings, the same or corresponding members or components will be denoted by the same or corresponding reference numerals, and redundant descriptions thereof will be omitted. In the following detailed description, numerous specific details are set forth in order to provide a thorough understanding of the present disclosure. However, it will be apparent to one of ordinary skill in the art that the present disclosure may be practiced without these specific details. In other instances, well-known methods, procedures, systems, and components have not been described in detail so as not to unnecessarily obscure aspects of the various embodiments.

Substrate Processing Apparatus

A substrate processing apparatus1according to an embodiment will be described with reference toFIGS.1and2. As illustrated inFIG.1, the substrate processing apparatus1is a batch type vertical heat treatment apparatus that heats a plurality of substrates W at once. The substrate W is, for example, a semiconductor wafer.

The substrate processing apparatus1includes a processing container10, a gas supplier30, an exhauster50, a heating part70, a gas flow regulator80, and a controller90.

The interior of the processing container10may be reduced in pressure. The processing container10has a double tube structure in which an inner tube11and an outer tube12are coaxially arranged.

The inner tube11has a cylindrical shape with an open lower end and a ceiling. The inner tube11forms therein a first region R1in which the substrate W is accommodated. The ceiling of the inner tube11is flat, for example. The inner tube11is formed of, for example, a heat-resistant material such as quartz.

The outer tube12has a cylindrical shape with an open lower end and a ceiling. The outer tube12is provided so as to cover a sidewall and the ceiling of the inner tube11. The outer tube12is provided outside the inner tube11with a second region R2interposed therebetween. The outer tube12is formed of a heat-resistant material such as quartz.

An accommodation portion13for accommodating a nozzle is formed in one side of the inner tube11along an axial direction (vertical direction) thereof. For example, a portion of the sidewall of the inner tube11protrudes outward to form a convex portion14, and an interior of the convex portion14is formed as the accommodation portion13.

A slit A1is formed in the sidewall of the inner pipe11at the opposite side so as to correspond to the accommodation portion13. The slit A1is an exhaust port through which a gas in the first region R1is exhausted. The slit A1has a rectangular shape with a vertical direction thereof as a longitudinal direction. A slit length of the slit A1may be the same as a length of a boat16, or may be longer than the length of the boat16.

A lower end of the processing container10is supported by a cylindrical manifold17. The manifold17is formed of, for example, stainless steel. A flange18is formed at an upper end of the manifold17. A lower end of the outer tube12is attached to and supported by the flange18. A sealing member19such as an O-ring is provided between the flange18and the lower end of the outer pipe12.

An annular support20is provided on an upper inner wall of the manifold17. A lower end of the inner tube11is attached to and supported by the support20. A cover21is air-tightly fitted into an opening in a lower end of the manifold17via a sealing member22such as an O-ring. The cover21and the sealing member22air-tightly close an opening in the lower end of the processing container10, that is, the opening of the manifold17. The cover21is formed of, for example, stainless steel.

A rotary shaft24, which rotatably supports the boat16via a magnetic fluid seal23, is provided through a central portion of the cover21. A bottom portion of the rotary shaft24is rotatably supported by an arm25aof an elevating mechanism25, which is configured as a boat elevator.

A rotary plate26is provided on an upper end of the rotary shaft24. The boat16is placed on the rotary plate26via a heat-insulation container27formed of quartz. Thus, by moving the elevating mechanism25up and down, the cover21and the boat16integrally move up and down to insert and separate the boat16into and from the processing container10. The boat16may be accommodated in the processing container10. The boat16holds a plurality of (for example, 50 to 150) substrates W on shelves along the vertical direction.

The gas supplier30includes a plurality of (for example, three) nozzles31to33. The plurality of nozzles31to33are provided in a line along the circumferential direction inside the accommodation portion13of the inner tube11. Each of the nozzles31to33is provided inside the inner pipe11along the vertical direction, and includes a base end bent in an L shape so as to pass through the manifold17. Each of the nozzles31to33is formed of, for example, quartz.

A plurality of gas holes31aare provided in the nozzle31at predetermined intervals along the vertical direction. The plurality of gas holes31aare oriented, for example, toward the center (the side of the substrate W) of the inner tube11. The nozzle31horizontally discharges a raw material gas, which is introduced from a raw material gas source (not illustrated), toward the substrate W from the plurality of gas holes31a. The raw material gas is, for example, a gas containing silicon or a metal.

A plurality of gas holes32aare provided in the nozzle32at predetermined intervals along the vertical direction. The plurality of gas holes32aare oriented, for example, toward the center (the side of the substrate W) of the inner tube11. The nozzle32horizontally discharges a reactive gas, which is introduced from a reactive gas source (not illustrated), toward the substrate W from the plurality of gas holes32a. The reactive gas is a gas for reacting with the raw material gas to produce a reaction product. The reactive gas is, for example, an oxidizing gas or a nitriding gas.

A plurality of gas holes33aare provided in the nozzle33at predetermined intervals along the vertical direction. The plurality of gas holes33aare oriented, for example, toward the center (the side of the substrate W) of the inner tube11. The nozzle33horizontally discharges a purge gas, which is introduced from a purge gas source (not illustrated), toward the substrate W from the plurality of gas holes33a. The purge gas is a gas for purging the raw material gas or the reactive gas remaining inside the processing container10. The purge gas is, for example, an inert gas such as a nitrogen gas or an argon gas.

The gas supplier30may mix a plurality of types of gases and discharge the same from one nozzle. Respective nozzles may have different shapes in different arrangements. The gas supplier30may be configured to supply other gases in addition to the raw material gas, the reactive gas, and the purge gas. The other gases may include a cleaning gas and an etching gas.

The exhauster50exhausts the gas, which is discharged from the interior of the inner tube11through the slit A1and is discharged from the exhaust port28through the second region R2between the inner tube11and the outer tube12. The exhaust port28is formed in an upper sidewall of the manifold17and above the support20. An exhaust pipe51is connected to the exhaust port28. The exhaust pipe51is provided with a pressure regulating valve52and a vacuum pump53in order from the upstream side toward the downstream side in a gas flow direction. The exhauster50regulates the internal pressure of the processing container10by the pressure regulating valve52while sucking the gas in the processing container10by the vacuum pump53under the control of the controller90.

The heating part70includes a cylindrical heater71. The heater71is provided radially outside the outer tube12so as to surround the outer tube12. The heater71heats the entire periphery of the processing container10, thereby heating each substrate W accommodated in the processing container10. The heating part70may further include a heat insulator.

The gas flow regulator80is provided in a gas flow path from the first region R1to the exhaust port28. The gas flow regulator80includes a cover member81and a partition plate82.

The cover member81is provided in the second region R2. The cover member81is provided to protrude from the sidewall of the inner tube11toward the outer tube12so as to cover the slit A1and forms a third region R3between the sidewall of the inner tube11and the cover member81. The cover member81is provided along the sidewall of the inner tube11and includes a circular arc portion in which a central angle in a horizontal cross section forms a circular arc of a predetermined angle. The predetermined angle is, for example, 45 degrees or more and 90 degrees or less. A vertical length of the cover member81is greater than the slit length of the slit A1and is equal to or less than the vertical length of the inner tube11. The cover member81is formed of, for example, a heat-resistant material such as quartz. The cover member81may be formed integrally with the inner tube11, or may be formed separately from the inner tube11.

The partition plate82is provided in the third region R3. The partition plate82extends along the radial direction of the inner tube11and divides the third region R3into two regions R3aand R3b. The region R3ais a region facing the slit A1. The region R3bis located downstream of the region R3ain the gas flow direction, and is a region facing a slit A3to be described later. The partition plate82is formed of, for example, a heat-resistant material such as quartz. The partition plate82may be formed integrally with the cover member81, or may be formed separately from the cover member81. The partition plate82is provided with a slit A2for communicating the region R3awith the region R3b. The slit A2is provided downstream of the slit A1in the gas flow direction.

The slit A3is provided in a sidewall of an end of the cover member81closer to the exhaust port28. The slit A3is provided downstream of the slit A2in the gas flow direction. The slit A3is oriented toward the exhaust port28. However, the slit A3may be oriented toward a sidewall of the outer tube12.

Each of the slits A1to A3has a rectangular shape, an elongated hole shape, or an elliptical shape with the vertical direction as the longitudinal direction and the horizontal direction as the transverse direction. The slits A1to A3have the same slit length. However, the slits A1to A3may have different slit lengths. The slit A1may have the widest slit width among three slits A1to A3. In this case, the concentration of the flow velocity near the slit A1is alleviated. At least one of the slits A1to A3may be divided into a plurality of slits in the vertical direction.

The gas flow regulator80regulates the flow of the gas and guides the gas to the exhaust port28by passing the gas in the first region R1through the slit A1, the slit A2, and the slit A3in this order.

A computer having one or more processors91, a memory92, an input/output interface (not illustrated) and an electronic circuit (not illustrated) may be applied to the controller90. The processor91is one of a CPU, an ASIC, an FPGA, a circuit composed of a plurality of discrete semiconductors, and the like, or a combination thereof. The memory92includes a volatile memory or a non-volatile memory (for example, a compact disk, a DVD, a hard disk, and a flash memory), and stores programs for operating the substrate processing apparatus1and recipes such as process conditions of a substrate processing. The processor91executes programs and recipes stored in the memory92, thereby controlling each component of the substrate processing apparatus1to perform various processing.

As described above, the substrate processing apparatus1according to the embodiment includes the gas flow regulator80having the plurality of slits A1to A3provided in the gas flow path from the first region R1to the exhaust port28from the upstream side toward the downstream side in the gas flow direction. In this way, by multiplexing the slits along the gas flow direction, it is possible to prevent uneven gas flow in the vertical direction of the first region R1. As a result, the uniformity of film formation characteristics between the substrates W (hereinafter referred to as “inter-plane uniformity”) is improved.

Further, according to the substrate processing apparatus1of the embodiment, by widening the slit width of the slit A1located closest to the first region R1as well as multiplexing the slits along the gas flow direction, the concentration of the flow velocity near the slit A1may be alleviated. As a result, the uniformity of film formation characteristics in the plane of the substrate W (hereinafter referred to as “in-plane uniformity”) is improved.

Further, according to the substrate processing apparatus1of the embodiment, exhaust gas distribution in the vertical direction may be controlled by multiplexing the slits along the gas flow direction and varying the slit lengths of the slits A1to A3.

On the other hand, in a substrate processing apparatus that does not have the gas flow regulator80, the discharge of the gas from the bottom of a height region (hereinafter referred to as “process region”) in which the substrate W is accommodated increases, and the discharge of the gas from the top of the process region decreases. For this reason, the gas may stay in the top of the process region inside the inner tube11, causing excessive decomposition of the raw material gas or deactivation of the reactive gas, which may deteriorate the inter-plane uniformity of film formation characteristics. Further, when the slit A1has a narrow slit width, the excessively decomposed gas may be concentrated near the slit A1, so that a film tends to be deposited on a periphery edge of the substrate W, which may deteriorate the in-plane uniformity.

Next, a gas flow regulator80A according to a first modification will be described with reference toFIG.3. The gas flow regulator80A is provided in the gas flow path from the first region R1to the exhaust port28. The gas flow regulator80A includes a first plate-shaped member86and a second plate-shaped member87.

The first plate-shaped member86extends along the radial direction of the inner tube11from the sidewall of the inner tube11toward the sidewall of the outer tube12, and narrows a gap between the sidewall of the inner tube11and the sidewall of the outer tube to form the slit A2. A vertical length of the first plate-shaped member86is, for example, greater than or equal to the vertical length of the process region and is less than or equal to the vertical length of the inner tube11.

The second plate-shaped member87is provided downstream of the first plate-shaped member86in the gas flow direction. The second plate-shaped member87extends along the radial direction of the inner tube11from the sidewall of the inner tube11toward the sidewall of the outer tube12, and narrows the gap between the sidewall of the inner tube11and the sidewall of the outer tube to form the slit A3. A vertical length of the second plate-shaped member87is, for example, greater than or equal to the vertical length of the process region and is less than or equal to the vertical length of the inner tube11.

Similarly to the gas flow regulator80, the gas flow regulator80A adjusts the flow of the gas and guides the gas to the exhaust port28by passing the gas in the first region R1through the slit A1, the slit A2, and the slit A3in this order. The substrate processing apparatus including the gas flow regulator80A also has the same effect as the substrate processing apparatus1described above.

Next, a gas flow regulator80B according to a second modification will be described with reference toFIG.4. The gas flow regulator80B differs from the gas flow regulator80A in that the first plate-shaped member86and the second plate-shaped member87extend along the radial direction of the inner tube11from the sidewall of the outer pipe12toward the sidewall of the inner pipe11.

The first plate-shaped member86extends along the radial direction of the inner tube11from the sidewall of the outer tube12toward the sidewall of the inner tube11, and narrows the gap between the sidewall of the inner tube11and the sidewall of the outer tube to form the slit A2. The vertical length of the first plate-shaped member86is, for example, greater than or equal to the vertical length of the process region, and is less than or equal to the vertical length of the inner tube11.

The second plate-shaped member87is provided downstream of the first plate-shaped member86in the gas flow direction. The second plate-shaped member87extends along the radial direction of the inner tube11from the sidewall of the outer tube12toward the sidewall of the inner tube11, and narrows the gap between the sidewall of the inner tube11and the sidewall of the outer tube12to form the slit A3. The vertical length of the second plate-shaped member87is, for example, greater than or equal to the vertical length of the process region, and is less than or equal to the vertical length of the inner tube11.

Similarly to the gas flow regulator80A, the gas flow regulator80B adjusts the flow of the gas and guides the gas to the exhaust port28by passing the gas in the first region R1through the slit A1, the slit A2, and the slit A3in this order. The substrate processing apparatus including the gas flow regulator80B also has the same effect as the substrate processing apparatus1described above.

Analysis Result

Analysis results which have confirmed that uneven gas flow in the vertical direction of the first region R1is suppressed by using the substrate processing apparatus1according to the embodiment will be described.

Analysis A was conducted by simulation to calculate, in the substrate processing apparatus1, a gas flow-rate distribution in the vertical direction at the positions of the slits A1to A3when the gas was discharged from the nozzle31to the first region R1and the gas was discharged through the exhaust port28. In Analysis A, the slit width of the slit A1was set to 40 mm, the slit width of the slit A2was set to 10 mm, and the slit width of the slit A3was set to 5 mm. In addition, the slit lengths of the slits A1to A3were set so as to vertically extend longer than the length of the process region. Further, the slit lengths of the slits A1to A3were set to be the same.

FIG.5is a diagram illustrating analysis results of the gas flow-rate distribution in the vertical direction. InFIG.5, the horizontal axis indicates each vertical region when the process region is vertically divided into eight equal regions, and the vertical axis indicates a gas flow-rate ratio in each region. In addition, the gas flow-rate ratio was calculated by the following equation (1).

InFIG.5, rhombic marks, square marks, and triangular marks indicate the gas flow-rate ratios at the positions of the slits A1, A2and A3, respectively.

As illustrated inFIG.5, it can be seen that the flow rate is larger at the bottom than at the top at the position of the slit A3, whereas at the position of the slit A1, there is almost no difference in the flow rate between the top and the bottom. It was found from this result that uneven gas flow in the vertical direction of the first region R1may be suppressed by providing the slit A1with a slit width of 40 mm, the slit A2with a slit width of 10 mm, and the slit A3with a slit width of 5 mm from the upstream side toward the downstream side in the gas flow direction.

Analysis B was conducted by simulation to calculate, in the substrate processing apparatus1, a gas flow-rate distribution in the vertical direction at the position of the slit A1when the gas was discharged from the nozzle31to the first region R1and the gas was discharged through the exhaust port28. In Analysis B, the simulation was performed by changing the slit widths of the slits A1to A3. In addition, the slit lengths of the slits A1to A3were set so as to vertically extend longer than the length of the process region. Further, the slit lengths of the slits A1to A3were set to be the same. In Analysis B, for comparison, a similar simulation was performed for a substrate processing apparatus having one slit A1without the slits A2and A3.

FIG.6is a diagram illustrating analysis results of the uniformity of a gas flow rate, and illustrates the uniformity of the gas flow rate in the vertical direction in each substrate processing apparatus. In addition, the uniformity was calculated by the following equation (2).

However, in Equation (2), the maximum value, the minimum value, and the average value are the maximum flow, the minimum value, and the average value of the flow rates in the eight regions of the slit A1, respectively.

InFIG.6, a first bar graph from the left side indicates the result when there is the slit A1alone (slit width: 40 mm). A second bar graph from the left side indicates the result when there is the slit A1alone (slit width: 5 mm). A third bar graph from the left side indicates the result when there are the slit A1(slit width: 40 mm), the slit A2(slit width: 10 mm) and the slit A3(slit width: 5 mm). A fourth bar graph from the left side indicates the result when there are the slit A1(slit width: 20 mm), the slit A2(slit width: 10 mm) and the slit A3(slit width: 5 mm). A fifth bar graph from the left side illustrates the result when there are the slit A1(slit width: 5 mm), the slit A2(slit width: 10 mm) and the slit A3(slit width: 20 mm).

As illustrated inFIG.6, it can be seen that the uniformity of the gas flow rate in the vertical direction at the position of the slit A1is in a range from 1.2% to 1.6% when the substrate processing apparatus includes the three slits A1to A3. On the other hand, it can be seen that the uniformity of the gas flow rate in the vertical direction at the position of the slit A1is in a range from 2.3% to 10.6% when the substrate processing apparatus includes the slit A1alone. It was found from this result that uneven gas flow in the vertical direction of the first region R1may be suppressed by providing multiple slits from the upstream side to the downstream side in the gas flow direction.

Further, as illustrated inFIG.6, it can be seen that, when the substrate processing apparatus includes the three slits A1to A3, the uniformity of the gas flow rate in the vertical direction at the position of the slit A1is good when setting the slit width of the slit A3to 5 mm rather than when setting the slit width of the slit A3to 20 mm. It was found from this result that uneven gas flow in the vertical direction of the first region R1may be particularly suppressed by narrowing the slit width of the slit A3. It is considered that this is because the exhaust conductance near the slit A3is deteriorated by narrowing the slit width of the slit A3facing the second region R2. In other words, the exhaust flow velocity tends to be high in a region below the slit A3close to the exhaust port28, and it is considered that the high exhaust flow velocity in the region below the slit A3is alleviated due to the deterioration of the exhaust conductance.

Analysis C was conducted by simulation to calculate, in the substrate processing apparatus1, similarly to Analysis A, a gas flow-rate distribution in the vertical direction at the positions of the slits A1to A3when the gas was discharged from the nozzle31to the first region R1and the gas was discharged through the exhaust port28. In Analysis C, the simulation was performed by changing the slit lengths of two slits A2and A3. In addition, the slit widths of the slits A1to A3were set to the same slit widths as those of the slits A1to A3in Analysis A.

FIG.7is a diagram illustrating an opening position of a slit. InFIG.7, regions of numbers “2” to “8” indicate each region in the vertical direction when the process region is divided into eight equal regions in the vertical direction. The region of number “2” is located at the top of the process region, and the region of number “8” is located at the bottom of the process region. A region of number “1” indicates a region above the process region, and a region of number “10” indicates a region below the process region. Further, the numbered regions with pear-shell pattern hatching indicate regions with openings, and the numbered regions without pear-shell pattern hatching indicate regions without openings. That is, inFIG.7, the slits A1and A2are slits that are open from above to below the process region. Further, the slit A3is a slit in which two central regions are open and the other regions are not open when the process region is divided into eight equal regions.

FIG.8is a diagram illustrating analysis results of a gas flow-rate distribution in the vertical direction, and illustrates results when the substrate processing apparatus includes the three slits A1to A3illustrated inFIG.7. InFIG.8, the horizontal axis indicates each vertical region when the process region is vertically divided into eight equal regions and the vertical axis indicates a gas flow-rate ratio in each region. In addition, the gas flow-rate ratio was calculated by the above-described equation (1). Further, inFIG.8, rhombic marks, square marks, and triangular marks indicate gas flow-rate ratios at the positions of the slits A1, A2and A3, respectively.

As illustrated inFIG.8, it can be seen that the gas flow-rate distribution has a convex shape in which the center in the vertical direction has a larger flow rate than the top and bottom at the position of the slit A1.

FIG.9is a diagram illustrating an opening position of a slit. InFIG.9, regions of numbers “2” to “8” indicate each region in the vertical direction when the process region is divided into eight equal regions in the vertical direction. The region of number “2” is located at the top of the process region, and the region of number “8” is located at the bottom of the process region. A region of number “1” indicates a region above the process region, and a region of number “10” indicates a region below the process region. Further, the numbered regions with pear-shell pattern hatching indicate regions with openings, and the numbered regions without pear-shell pattern hatching indicate regions without openings. That is, inFIG.9, the slit A1is a slit that is open from above to below the process region. Further, the slit A2is a slit in which two upper regions and two lower regions are open and the other regions are not open when the process region is divided into eight equal regions. Further, the slit A3is a slit in which two central regions are open and the other regions are not open when the process region is divided into eight equal regions.

FIG.10is a diagram illustrating analysis results of a gas flow-rate distribution in the vertical direction, and illustrates results when the substrate processing apparatus includes the three slits A1to A3illustrated inFIG.9. InFIG.10, the horizontal axis indicates each vertical region when the process region is vertically divided into eight equal regions, and the vertical axis indicates the gas flow-rate ratio in each region. In addition, the gas flow-rate ratio was calculated by the above-described equation (1). Further, inFIG.10, rhombic marks, square marks, and triangular marks indicate gas flow-rate ratios at the positions of the slits A1, A2and A3, respectively.

As illustrated inFIG.10, it can be seen that the gas flow-rate distribution has a concave shape in which the center in the vertical direction has a smaller flow rate than the top and bottom at the position of the slit A1.

As described above, it was found from the results illustrated inFIGS.8and10that exhaust gas distribution in the vertical direction may be controlled by changing the slit lengths of the slits A2and A3.

In addition, in the above embodiment, the inner tube11is an example of an inner cylinder, and the outer tube12and the manifold17are examples of an outer cylinder.

The embodiments disclosed herein should be considered to be exemplary and not limitative in all respects. The above embodiments may be omitted, replaced or modified in various embodiments without departing from the scope of the appended claims and their gist.

In the above embodiment, a case where the outer tube12and the manifold17, which are formed of different materials, constitute the outer cylinder, has been described, but the present disclosure is not limited thereto. For example, the outer tube12and the manifold17may be formed of the same material and may be formed integrally with each other.

According to the present disclosure in some embodiments, it is possible to suppress uneven gas flow within a processing container.