JP2009152292A - Apparatus for cleaning substrate and method of cleaning substrate by using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an apparatus for cleaning a substrate that hardly causes unevenness in the processing of stripping resist or flaws due to concentration of particles, and to provide a method of cleaning the substrate using the apparatus. <P>SOLUTION: The apparatus for cleaning the substrate uses a main channel 12, a first interconnection passage 30 and a second interconnection passage 35 interconnected with a cleaning space S, and a switching means Sw. The switching means Sw switches a first interconnection state where supercritical fluid is supplied from the other end 12b of the main channel 12 through the second interconnection passage 35 into the cleaning space S and thence discharged to one end 12a of the main channel 12 through the first interconnection passage 30, and a second interconnection state where supercritical fluid is supplied from the other end 12b of the main channel 12 through the first interconnection passage 30 into the cleaning space S and thence discharged to one end 12a of the main channel 12 through the second interconnection passage 35. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a substrate cleaning apparatus for cleaning a substrate surface such as a semiconductor substrate or a glass substrate for flat panel display and a resist stripping process using a supercritical fluid, and a substrate cleaning method using the substrate cleaning apparatus.

  In the manufacturing process of glass substrates for semiconductor manufacturing equipment and flat panel displays (FPD), when forming a pattern on the substrate, resist that is not required after pattern formation or particles that are generated during etching and remain on the substrate A cleaning step for removing the substrate from the substrate is an essential step.

  Conventionally, as a method for cleaning the substrate, a so-called wet method of cleaning the substrate surface using a liquid such as water or a cleaning liquid has been employed. However, in recent years, with the miniaturization of circuit pattern sizes, there has been a problem that the circuit pattern formed on the substrate collapses due to the surface tension of the liquid used for cleaning (pattern collapse) in the wet cleaning. Therefore, in recent years, a cleaning method using a supercritical fluid has been adopted for cleaning the substrate.

  The substrate cleaning apparatus for performing the cleaning method using the supercritical fluid includes a substrate cleaning chamber and a circulation pump for liquid feeding, and a circulating flow for circulating the supercritical fluid from one end to the other end. What is provided with a road is known. In this substrate cleaning apparatus, a supercritical fluid to which a cleaning agent or the like is added is supplied from the other end of the circulation channel into the substrate cleaning chamber, and the supercritical fluid flows along the surface (cleaning surface) of the substrate. The substrate is cleaned. The supercritical fluid after this substrate cleaning is discharged together with the resist and particles from the substrate cleaning chamber to one end of the circulation channel. The supercritical fluid discharged to one end of the circulation channel is sent again toward the other end by the circulation pump and supplied into the substrate cleaning chamber. As described above, in the substrate cleaning apparatus, the supercritical fluid circulates between the circulation flow path and the substrate cleaning chamber, and the substrate surface is cleaned without causing the pattern collapse of the fine circuit pattern in the substrate cleaning chamber. Do.

  In the substrate cleaning apparatus, the supercritical fluid flows in one direction in the circulation channel by the circulation pump. For this reason, in the substrate cleaning chamber, from the communication site with the other end of the circulation channel to the communication channel with one end of the circulation channel, that is, from the supercritical fluid supply position into the substrate cleaning chamber to the outside of the substrate cleaning chamber. The supercritical fluid flows in one direction toward the discharge position. In this case, a place where the flow is slow or a place where the flow is concentrated occurs on the substrate, and there are cases where the substrate surface is scratched due to processing unevenness or particle concentration in the resist peeling process.

  In view of the above-described problems, an object of the present invention is to provide a substrate cleaning apparatus and a substrate cleaning method in which processing unevenness in resist stripping processing and scratches due to particle concentration hardly occur.

  Therefore, in order to solve the above problems, a substrate cleaning apparatus according to the present invention includes a substrate cleaning chamber having a cleaning space for cleaning a substrate with a supercritical fluid, a pump for liquid feeding, and the other from one end. A main flow path for flowing the supercritical fluid toward the end, a first communication path communicating with the cleaning space, a second communication path communicating with the cleaning space, and one end of the main flow path A first communication state in which the other end portion of the main flow path is communicated with the second communication path while communicating with the first communication path, and one end portion of the main flow path is communicated with the second communication path and the main flow path And a switching means for switching to the second communication state in which the other end communicates with the first communication path.

  In such a configuration, by switching the switching means, it is possible to reverse the flow direction of the supercritical fluid in the cleaning space without changing the flow direction of the supercritical fluid flowing through the main flow path.

  That is, when the switching means is switched, in the first communication path, the flow of the supercritical fluid from the cleaning space toward one end of the main flow path is switched to the flow from the other end of the main flow path toward the cleaning space. On the other hand, in the second communication path, the flow of the supercritical fluid from the other end of the main channel to the cleaning space is switched to the flow from the cleaning space to one end of the main channel, or vice versa. Switch. Therefore, in the main flow path, the supercritical fluid always flows from one end to the other end, and in the cleaning space, the supercritical fluid is directed from the communication portion with the second communication path to the communication portion with the first communication path. The flow of the critical fluid is reversed by the switching, and the flow is switched from the communication part with the first communication path to the communication part with the second communication path, or vice versa.

  As a result, the location where the flow is slow or the location where the flow is concentrated, which may occur when the supercritical fluid flows in one direction in the cleaning space, is moved by the switching, so that the resist stripping process is performed on the substrate surface. Done uniformly. Furthermore, the location where the flow concentrates moves, the location where the washed-out particles concentrate also moves, and the generation of scratches at the location where the flow concentrates on the substrate surface is also suppressed.

  Moreover, since the direction of the supercritical fluid flowing through the main flow path is always the same direction, it is not necessary to reversely rotate the pump when reversing the flow of the supercritical fluid in the cleaning space, and the physical load on the pump is reduced. It is suppressed and failure etc. are suppressed.

  In the substrate cleaning apparatus according to the present invention, the first communication path communicates with the cleaning space at a position facing a central portion of the substrate disposed in the cleaning space, and the second communication path includes the cleaning path. The structure which communicates with the said washing | cleaning space may be sufficient in the outer peripheral part of the board | substrate arrange | positioned in space.

  According to this configuration, when the supercritical fluid is supplied from the first communication path to the cleaning space, the supercritical fluid is discharged toward the central portion of the substrate disposed in the cleaning space. The fluid reaches the central portion of the substrate and then flows in the entire circumferential direction. Therefore, the entire substrate can be cleaned by flowing the supercritical fluid along the substrate. On the other hand, the flow of the supercritical fluid can be reversed by switching the switching means.

  In the above-described configuration, it is preferable that the second communication path communicates with the cleaning space at a plurality of locations at intervals in the circumferential direction of the substrate.

  With such a configuration, the flow of the supercritical fluid along the substrate flows from the entire circumferential direction of the peripheral portion of the substrate toward the central portion, and the entire circumferential direction of the peripheral portion of the substrate from the central portion. It becomes possible to reverse to the flow toward. Therefore, the entire substrate surface is more evenly cleaned.

  The switching means has a first on-off valve, has a first connection path for connecting one end of the main flow path and the first communication path, and a second on-off valve, and has one end of the main flow path. A second connection path connecting the first communication path to the second communication path, a third on-off valve, a third connection path connecting the other end of the main flow path to the first communication path, and a fourth on-off valve A first connection path that connects the other end of the main flow path to the second communication path, and that opens the first and fourth on-off valves and closes the second and third on-off valves. An open / close control unit that performs open / close control of the first to fourth open / close valves that switches between the communication state and the second communication state in which the first and fourth open / close valves are closed and the second and third open / close valves are opened. And the structure which has these is preferable.

  By being configured in this way, by a simple configuration such as a flow path having an open / close valve and an open / close control unit that performs open / close control of the open / close valve, without changing the direction of the flow of the supercritical fluid flowing through the main flow path, It becomes possible to reverse the flow in the cleaning space.

  Further, in order to solve the above problems, a substrate cleaning method according to the present invention is a substrate cleaning method for cleaning a surface of a substrate by discharging a supercritical fluid supplied from a main flow path into a cleaning space. A main flow path through which the supercritical fluid flows from one end to the other end, a first communication path and a second communication path respectively communicating with the cleaning space, and each end of the main flow path and the first and second communication paths Switching means for switching the communication state with the passage, the supercritical fluid is supplied into the cleaning space from the other end of the main flow path through the second communication path, and the main flow from the cleaning space through the first communication path. A first communication state in which the supercritical fluid is discharged to one end of the passage; a supercritical fluid is supplied into the cleaning space from the other end of the main flow path through the first communication path; and a second from the cleaning space. Supercritical fluid at one end of main channel through communication path Wherein the switching and the second communication state being discharged, said switching means.

  According to this configuration, as described above, by switching the switching means, it is possible to reverse the flow of the supercritical fluid in the cleaning space without changing the direction of the flow of the supercritical fluid flowing through the main flow path. Become.

  Therefore, the location where the flow is slow or the location where the flow is concentrated, which may occur when the supercritical fluid flows in one direction in the cleaning space, is moved by the switching, and the resist stripping process is uniform on the substrate surface. To be done. Furthermore, the location where the flow concentrates moves, the location where the washed-out particles concentrate also moves, and the generation of scratches at the location where the flow concentrates on the substrate surface is also suppressed.

  Also, in the substrate cleaning method according to the present invention, the switching means includes a first on-off valve, a first connection path that connects one end of the main flow path and the first communication path, and a second on-off valve. A second connection path that connects one end of the main flow path and the second communication path, and a third on-off valve that connects the other end of the main flow path and the first communication path. A third connection path, a fourth connection path having a fourth open / close valve and connecting the other end of the main flow path to the second communication path, and opening the first and fourth open / close valves and The switching means between the first communication state in which the second and third on-off valves are closed and the second communication state in which the first and fourth on-off valves are closed and the second and third on-off valves are opened. A configuration for switching between is preferable.

  With this configuration, as described above, the flow direction of the supercritical fluid flowing through the main flow path is changed by a simple configuration such as a flow path having an open / close valve and an open / close control unit that performs open / close control of the open / close valve. Without reversing the flow in the cleaning space.

  As described above, according to the present invention, it is possible to provide a substrate cleaning apparatus and a substrate cleaning method in which processing unevenness in resist stripping processing and scratches due to concentration of particles hardly occur.

  Hereinafter, an embodiment of the present invention will be described with reference to the accompanying drawings.

The substrate cleaning apparatus according to the present embodiment uses a supercritical fluid (hereinafter also simply referred to as “supercritical fluid”) to which a cleaning agent or the like is added, and a glass substrate for a semiconductor substrate (wafer) or a flat panel display (FPD). (Hereinafter, both are also simply referred to as “substrate”). In particular, the apparatus is used when a substrate on which a fine circuit pattern is formed is cleaned so as not to cause pattern collapse. Note that the supercritical fluid used in the present embodiment is carbon dioxide (CO ₂ ) that has become a supercritical state by being placed under a high temperature and high pressure above the critical point.

  Specifically, as shown in FIGS. 1 and 2, the substrate cleaning apparatus 10 has a circulation channel 11 for circulating a supercritical fluid and a cleaning space S, and is supplied from the circulation channel 11. And a substrate cleaning chamber 40 in which resist removal processing and cleaning processing are performed on the substrate w accommodated in the cleaning space S using the supercritical fluid.

  The circulation flow path 11 includes a main flow path pipe 12 that allows a supercritical fluid to flow from one end portion 12a toward the other end portion 12b, and a first communication path 30 that has one end portion communicating with the cleaning space S of the substrate cleaning chamber 40. And the second communication passage 35, and a connection portion J that connects each end portion (one end portion 12a or the other end portion 12b) of the main flow channel pipe 12 to the other end portion of the first or second communication passages 30 and 35. It is configured.

The main flow path pipe 12 has a circulation pump 17 for feeding the supercritical fluid in the main flow path pipe 12 from the one end portion 12a toward the other end portion 12b at an intermediate portion. An exhaust pipe (exhaust line) 18, a carbon dioxide (CO ₂ ) supply pipe (CO ₂ supply line) 19, and a washing are sequentially provided from the upstream side downstream of the one end portion 12 a of the main flow path pipe 12 and upstream of the circulation pump 17. An agent (additive) supply pipe (cleaning agent supply line) 20 is connected. Exhaust of carbon dioxide from the main flow path pipe 12 is performed by opening and closing a valve 18 a provided in the exhaust pipe 18. Carbon dioxide is supplied to the main flow path pipe 12 by opening and closing a valve 19 a provided in the carbon dioxide supply pipe 19. The cleaning agent is supplied to the main channel tube 12 by opening and closing a valve 20 a provided in the cleaning agent supply tube 20.

  The main channel pipe 12 is provided with a filter 21 on the downstream side of the circulation pump 17 and on the upstream side of the other end portion 12b. This filter 21 is generated when the resist removal and cleaning processing of the substrate w is performed in the substrate cleaning chamber 40, and the stripped resist pieces and particles circulating along with the supercritical fluid in the circulation channel 11 are applied to the substrate w. In order to prevent troubles such as adhesion again, the resist pieces and particles are removed.

  The connecting part J has first to fourth four ports J1 to J4. The other end part 12b of the main channel pipe 12 is connected to the first port J1, and the main channel pipe 12 is connected to the second port J2. The other end of the first communication path 30 is connected to the third port J3, and the other end of the second communication path 35 is connected to the fourth port J4. The connection portion J is configured to be switchable between a first communication state and a second communication state, which will be described later. In the present embodiment, the connection portion J is composed of four connection pipes 13 to 16. The four connecting pipes 13 to 16 have a first on-off valve 13a, a first connecting pipe 13 that connects one end 12a of the main flow path pipe 12 and the other end of the first communication path 30, and a second The on-off valve 14a has a second connecting pipe 14 that connects one end 12a of the main flow path pipe 12 and the other end of the second communication path 35, and a third on-off valve 15a. The third connecting pipe 15 that connects the other end portion 12b and the other end portion of the first communication passage 30 and a fourth on-off valve 16a are provided. The other end portion 12b of the main flow passage tube 12 and the second communication passage 35 are connected to each other. It is the 4th connection pipe 16 which connects the other end part.

  The first to fourth on-off valves 13a to 16a are each of an open state in which the supercritical fluid can flow through the first to fourth connection pipes 13 to 16, and a closed state in which the supercritical fluid cannot flow. A valve that can be switched between two states. In this embodiment, an air operated valve is used. The opening / closing control of these opening / closing valves 13a to 16a is performed by the opening / closing control unit C1.

  The opening / closing control unit C1 constitutes a part of the device control unit C that controls the substrate cleaning apparatus 10. The opening / closing control unit C1 may be configured by a program stored in the device control unit C, or may be configured by a control device for controlling the opening / closing valve attached to the device control unit C. Details of the control of the opening / closing control unit C1 will be described later.

  The first to fourth connecting pipes 13 to 16 having the on-off valves 13a to 16a and the on-off control unit C1 for performing on-off control of the first to fourth on-off valves 13a to 16a constitute the switching means Sw. By this switching means Sw, the one end portion 12a of the main flow channel pipe 12 is communicated with the other end portion of the first communication passage 30, and the other end portion 12b of the main flow channel tube 12 is communicated with the other end portion of the second communication passage 35. In the first communication state, one end portion 12a of the main flow channel pipe 12 is communicated with the other end portion of the second communication passage 35, and the other end portion 12b of the main flow channel tube 12 is communicated with the other end portion of the first communication passage 30. It can be switched to the second communication state.

  As shown in FIG. 3, the substrate cleaning chamber 40 includes a first branch channel 37 and a plurality of second branch channels 38, 38,... Constituting the one end portion of the second communication path 35, and a cleaning space S. Fluid passage ports 41a and 41b for discharging (or supplying) the supercritical fluid to the outside. The details of the first branch channel 37 and the second branch channel 38 will be described later.

  The cleaning space S of the substrate cleaning chamber 40 is a space formed in a horizontal substantially disk shape, and when the substrate w is placed, a circumferential inner wall 42 surrounding the substrate w from the peripheral direction and a pair of upper and lower surfaces facing each other. Of the opposite walls (the upper opposite wall 43 and the lower opposite wall 44). The inner wall 42 has a circular shape in plan view, and the inner wall 42 is provided with a plurality of second branch channels 38, 38,. The lower facing wall 44 is configured by an upper part of a stage 45 that can be moved up and down, is formed so that the upper surface is a smooth horizontal surface, and the substrate w carried into the cleaning space S is disposed thereon. When the stage 45 is lowered or raised, the cleaning space S communicates with the outside, and a substrate insertion port (not shown) for loading and unloading the substrate w into and from the cleaning space S opens and closes.

  The upper facing wall 43 has a peripheral edge 43a inclined radially outward and upward, and a pair (two) of fluid passage ports 41a and 41b are provided at the center.

  Each fluid passage port 41a or 41b is connected to a flow path switching valve 32 (described later) disposed outside the substrate cleaning chamber 40 through switching pipes 31a and 31b. The flow path switching valve 32 and the switching pipes 31a and 31b constitute one end of the first communication path 30 as will be described later.

  The first communication passage 30 communicates with the cleaning space S at a position where one end thereof faces the central portion of the substrate w disposed in the cleaning space S, and the other end of the first communication passage 30 via the connection portion J. Connected to one end 12a and the other end 12b. In the present embodiment, the other end portion of the first communication passage 30 is connected to the one end portion 12 a of the main flow path tube 12 via the first connection pipe 13 and the main flow path pipe 12 via the third connection pipe 15. Is connected to the other end 12b. On one end portion side of the first communication passage 30, a pair of switching pipes 31 a and 31 b and a flow path switching valve 32 are provided in order from the end, and each switching pipe 31 is provided in the substrate cleaning chamber 40. The fluid passages 41a and 41b communicate with the cleaning space S. That is, one fluid passage port 41a communicates with the flow path switching valve 32 through one switching pipe 31a, and the other fluid passage port 41b communicates with the flow path switching valve 32 through the other switching pipe 31b.

  The flow path switching valve 32 is a valve for switching the flow path so that the supercritical fluid flows alternately in one switching pipe 31a and the other switching pipe 31b.

  The second communication path 35 has one end communicating with the cleaning space S at the outer peripheral portion of the substrate w disposed in the cleaning space S, and the other end connected with the one end 12a of the main flow channel pipe 12 via the connection portion J. Connected to the other end 12b. In the present embodiment, the other end portion of the second communication path 35 is connected to the one end portion 12 a of the main flow path tube 12 via the second connection pipe 14 and the main flow path pipe 12 via the fourth connection pipe 16. Is connected to the other end 12b. Specifically, the one end portion of the second communication path 35 communicates with the cleaning space S at a plurality of locations at intervals in the circumferential direction of the substrate w disposed in the cleaning space S. Specifically, the second communication path 35 is connected to the substrate cleaning chamber 40 at one end and is connected to the fourth port J4 of the connection portion J to form a single flow path. 36, a first branch flow path 37 connected to one end of the main pipe 36 and disposed at a position surrounding the cleaning space S, and a plurality of first branch flow paths 37 and the cleaning space communicating with each other. It is comprised by 2 branch flow paths 38,38, .... As described above, a part of the second communication path 35, that is, the first branch flow path 37, the plurality of second branch flow paths 38, 38,... And one end of the main pipe 36 are in the substrate cleaning chamber 40. Has been placed.

  One end of the main pipe 36 is connected to the first branch flow path 37 formed in the substrate cleaning chamber 40 as described above, and the other end is one end of the main flow path pipe 12 via the second connection pipe 14. 12 a and connected to the other end portion 12 b of the main flow path pipe 12 through the fourth connection pipe 16.

  The first branch channel 37 distributes the supercritical fluid supplied from the main pipe 36 to the plurality of second branch channels 38, 38,... Or joins the supercritical fluid from each second branch channel 38. This is a flow path for supplying the main pipe 36. The first branch flow path 37 is formed in an annular flow path that is concentric with the wall surface of the inner wall 42 that defines the cleaning space S. Further, the first branch flow path 37 is formed outside the wall surface (in the radial direction outside the cleaning space S) so that the distance from the wall surface of the inner wall 42 is constant, and has an inner diameter at each position in the axial direction. It is formed to be the same.

  A plurality of second branch channels 38, 38,... Are connected to the first branch channel 37, and the inner diameter of these second branch channels 38, 38,. It is formed to be smaller than that. The plurality of second branch flow paths 38, 38,... Are provided at intervals along the inner wall 42 and can discharge (supply) the supercritical fluid into the cleaning space S at a predetermined angle α with respect to the inner wall 42. Are provided respectively. Specifically, the plurality of second branch flow paths 38, 38,... Are provided on the inner wall 42 so as to be equally spaced along the circumferential direction of the inner wall 42, and a common plane (horizontal virtual plane V: FIG. 2)) to discharge the supercritical fluid. That is, all the second branch flow paths 38, 38,... Are provided at the same height with respect to the wall surface of the lower facing wall 44. Each of the second branch flow paths 38 is provided so as to discharge the supercritical fluid in a clockwise direction in a plan view so that the horizontal angle with respect to the inner wall 42 is α. Each of the second branch channels 38 has an equal length and an inner diameter, and is formed in an arc shape that is curved clockwise along the horizontal virtual plane V. Each of the second branch flow paths 38 is provided on the inner wall 42 so that the front end surface on the cleaning space S side is flush with the wall surface of the inner wall 42.

  In the present embodiment, each of the second branch flow paths 38 separates the inner wall 42 in the vertical direction at the position of the virtual plane V, cuts a groove in the facing separation surface, and combines the separated inner walls 42 together. It may be formed by embedding the pipe material in the inner wall 42.

  The substrate cleaning apparatus 10 according to the present embodiment has the above-described configuration. Next, the operation of the substrate cleaning apparatus 10 will be described with reference to FIGS. 4 (a) and 4 (b).

  First, the stage 45 is lowered, and the substrate w is carried into the cleaning space S from the substrate insertion opening opened in the substrate cleaning chamber 40 in the lowered state. After the substrate w is carried in, the stage 45 is raised and the substrate insertion port is closed, so that the cleaning space S becomes liquid-tight and air-tight.

Next, the valve 19a is opened with the valves 18a and 20a closed, and the components constituting the circulation cycle in which the supercritical fluid such as the circulation channel 11 and the substrate cleaning chamber 40 circulates from the carbon dioxide supply pipe 19 are included. A supercritical fluid (supercritical CO ₂ ) is filled. Further, the valve 20a is temporarily opened, a predetermined amount of cleaning agent is added to the supercritical fluid from the cleaning agent supply pipe 20, and the supercritical fluid is circulated in the circulation cycle by the circulation pump 17.

  At this time, the connection pipes 13 to 16 constituting the connection portion J are in the first communication state by the switching means Sw. That is, the first and fourth on / off valves 13a and 16a are opened and the second and third on / off valves 14a and 15a are closed by the on / off control unit C1.

  In the first communication state, the supercritical fluid flows in the main flow path pipe 12 from the one end portion 12a toward the other end portion 12b. Then, the supercritical fluid is supplied into the cleaning space S from the other end portion 12 b of the main flow path pipe 12 through the second communication path 35, and one end portion of the main flow path pipe 12 from the cleaning space S through the first communication path 30. The supercritical fluid is discharged at 12a. Therefore, in this first communication state, the supercritical fluid moves from the communication site with the second communication channel 35 toward the communication site with the first communication channel 30 in the cleaning space S, that is, each second branch channel 38. Flows toward the fluid passage ports 41a and 41b (see FIG. 4A).

  Specifically, in the first communication state, the supercritical fluid is supplied from the other end portion 12 b of the main flow path pipe 12 to the main pipe 36 of the second communication path 35 through the fourth connection pipe 16 of the connection portion J. The supercritical fluid supplied to the main pipe 36 is introduced into the substrate cleaning chamber 40 by the main pipe 36. The introduced supercritical fluid is distributed to each second branch channel 38 by the first branch channel 37 and is discharged into the cleaning space S from each second branch channel 38. The supercritical fluid discharged into the cleaning space S flows on the substrate surface toward the fluid passage ports 41a and 41b. In this way, the supercritical fluid flows along the substrate surface, whereby the resist peeling process and the cleaning process of the substrate w are performed. Then, the supercritical fluid that has reached the fluid passage ports 41a and 41b is discharged from the cleaning space S through one of the fluid passage ports 41a and 41b. The discharged supercritical fluid flows from the first communication path 30 to the one end portion 12 a of the main flow path pipe 12 through the first connection pipe 13.

  When the supercritical fluid is discharged into the cleaning space S, the first branch flow path 37 has the same inner diameter in the axial direction, so the pressure at each position in the axial direction is the same. Accordingly, the supercritical fluid is supplied to each second branch flow path 38 at the same pressure, and the flow rates of the supercritical fluid discharged from the second branch flow paths 38 into the cleaning space S are the same.

  When the supercritical fluid supplied into the cleaning space S is discharged from each of the second branch channels 38, the supercritical fluid is all in the clockwise direction in plan view from the inner wall 42 of the substrate cleaning chamber 40 that defines the cleaning space S. It is discharged into the cleaning space S. By being discharged in this manner, the supercritical fluid flows while forming a vortex along the substrate surface disposed in the cleaning space S from the inner wall 42 side toward the center of the cleaning space S. A pseudo single wafer spin cleaning is performed on the substrate w by the vortex of the supercritical fluid.

  In this state, after a predetermined time elapses, the connection pipes 13 to 16 constituting the connection portion J are switched to the second communication state by the switching means Sw. That is, the first and fourth on-off valves are closed and the second and third on-off valves are opened by the on-off controller C1. Thus, by opening and closing each of the on-off valves 13a to 16a, the supercritical fluid is supplied into the cleaning space S from the other end portion 12b of the main flow path pipe 12 through the first communication path 30, and from the cleaning space S. The supercritical fluid is discharged from the one end portion 12 a of the main flow path pipe 12 through the second communication path 35.

  Specifically, in the second communication state, the supercritical fluid is supplied to the first communication path 30 from the other end portion 12 b of the main flow path pipe 12 through the third connection pipe 15. The supercritical fluid supplied to the first communication path 30 flows through the first communication path 30 and is discharged (supplied) into the cleaning space S through one of the fluid passage ports 41a and 41b. The supercritical fluid discharged into the cleaning space S reaches the central portion of the substrate surface and then flows toward the second branch flow path 38 over the entire circumferential direction of the substrate w. The supercritical fluid that has reached the inner wall 42 of the cleaning space S is discharged from each second branch channel 38. The supercritical fluid discharged from each second branch flow path 38 joins in the first branch flow path 37, is sent to the main pipe 36, and is discharged out of the substrate cleaning chamber 40 through the main pipe 36. The discharged supercritical fluid is supplied to the one end portion 12 a of the main flow path pipe 12 through the second connection pipe 14.

  As described above, the connection pipes 13 to 16 constituting the connection portion J are switched from the first communication state to the second communication state, so that the flow direction of the supercritical fluid flowing through the main flow path pipe 12 is not changed. In the cleaning space S, the supercritical fluid directed from the communication part (each second branch flow path 38) to the second communication path 35 to the communication part (fluid passage ports 41a and 41b) to the first communication path 30 is obtained. The flow is reversed by the switching, and the flow is switched to the flow from the communication portion (fluid passage ports 41a and 41b) with the first communication passage 30 toward the communication portion (each second branch flow path 38) with the second communication passage 35. (See FIG. 4B).

  Thereafter, the second communication state is switched again to the first communication state, and this switching is repeated once or a plurality of times. As described above, when the communication state is switched from the first communication state to the second communication state or from the second communication state to the first communication state by the switching means Sw, the flow of the supercritical fluid flowing in the cleaning space S is reversed each time. Even if the connection portion J (the first to fourth connection pipes 13 to 16 in this embodiment) is alternately switched between the first communication state and the second communication state, The supercritical fluid always flows from the one end portion 12a toward the other end portion 12b. The switching timing of the switching means Sw is performed at a predetermined cycle by the opening / closing control unit C1, and this cycle can be arbitrarily adjusted.

  On the other hand, in the flow path switching valve 32, the supercritical fluid first flows through one switching pipe 31a, so that the supercritical fluid is supplied into the cleaning space S or discharged from the cleaning space S through the one fluid passage port 41a. Has been switched. In this state, when the flow path switching valve 32 is switched, the switching pipe through which the supercritical fluid can flow is switched to the other switching pipe 31b. By switching in this way, the fluid passage port discharged or supplied from the cleaning space S is switched to the fluid passage port 41b on the other side. Therefore, the position at which the supercritical fluid is supplied to or discharged from the cleaning space S is switched from one fluid passage port 41a to the other fluid passage port 41b, and the supercritical fluid flowing through the cleaning space S is changed. The flow changes. The switching timing of the flow path switching valve 32 is performed at a predetermined cycle by a timer (not shown). This timer switching cycle can be arbitrarily adjusted.

  It should be noted that only by switching the switching means Sw, the place where the flow of the supercritical fluid formed in the cleaning space S is slow and the place where the flow is concentrated moves and the resist stripping process is performed uniformly. Furthermore, if the generation of scratches due to the concentration of particles is suppressed, the number of fluid passage ports provided in the upper facing wall 43 may be only one. Further, by providing three or more fluid passage openings on the upper facing wall 43, the flow of the supercritical fluid can be controlled more freely. In addition, when there is one fluid passage port, the flow path switching valve 32 and the switching pipe need not use 31a and 31b. In this case, the 1st communicating path 30 is comprised by one pipe material etc. from one end part to the other end part. In addition, when there are three or more fluid passage ports, a number of switching pipes corresponding to the fluid passage openings are arranged, and one or a plurality of switching pipes are disposed at the end of the plurality of switching pipes opposite to the cleaning space S. A flow path switching valve is provided that can switch the flow path so that the supercritical fluid can flow through the tubes in order.

  As described above, the substrate surface cleaning (cleaning process) such as resist stripping and particle cleaning of the substrate surface carried into the cleaning space S is performed by the flow of the supercritical fluid in the cleaning space S. At this time, the switching state Sw (opening / closing control unit C1) switches the communication state at the connection portion J, that is, the opening / closing control of the opening / closing valves 13a to 16a of the connection pipes 13 to 16 and the flow path switching by a timer (not shown). By controlling the switching timing of the valve 32, the reversal of the flow of the supercritical fluid formed in the cleaning space S is controlled, and the substrate w is cleaned. When the cleaning of the substrate w is completed, the valve 18a of the exhaust pipe 18 is opened, and the supercritical fluid is discharged from the circulation cycle through the exhaust pipe 18. After discharging the supercritical fluid, the substrate w is unloaded from the cleaning space S in the reverse procedure of loading.

    Next, the operation and effect of the substrate cleaning apparatus 10 according to the present embodiment will be described.

  In the substrate cleaning apparatus 10, the direction of the supercritical fluid in the cleaning space S is reversed without changing the direction of the flow of the supercritical fluid flowing through the main flow path pipe 12 by switching the switching unit Sw. Is possible.

  That is, when the switching means Sw is switched, the flow from the cleaning space S toward the one end portion 12a of the main flow channel pipe 12 in the first communication passage 30 is transferred from the other end portion 12b of the main flow channel tube 12 to the cleaning space S. Switch to the supercritical fluid flow. On the other hand, in the second communication path 35, the flow from the other end portion 12 b of the main flow path pipe 12 toward the cleaning space S becomes a supercritical fluid flow from the cleaning space S toward the one end section 12 a of the main flow path pipe 12. Switch. Or, in each of the communication passages 30 and 35, the switching is reversed. For this reason, in the main channel pipe 12, the supercritical fluid always flows from the one end portion 12a to the other end portion 12b, whereas in the cleaning space S, the communication portion (each second passage) with the second communication passage 35 is provided. The flow of the supercritical fluid from the branch flow path 38) toward the communication part (fluid discharge part 41) with the first communication path 30 is reversed by the switching, and the second communication path is communicated from the communication part with the first communication path 30. It switches to the flow toward the communication part with 35. Or switch to the reverse.

  As a result, since the location where the flow is slow or the location where the flow is concentrated that occurs when the supercritical fluid flows in one direction in the cleaning space S is moved by the switching, the resist stripping process is performed on the substrate surface. Is performed uniformly. Furthermore, the location where the flow concentrates moves, the location where the washed-out particles concentrate also moves, and the generation of scratches at the location where the flow concentrates on the substrate surface is also suppressed.

  Moreover, since the direction of the supercritical fluid flowing through the main flow pipe 12 is always the same direction, there is no need to reversely rotate the circulation pump 17 when reversing the flow of the supercritical fluid in the cleaning space S. The physical load on 17 is suppressed, and failures and the like are suppressed.

  Further, the first communication path 30 is at a position facing the central portion of the substrate w disposed in the cleaning space S, and the second communication path 35 is an outer peripheral portion of the substrate w disposed in the cleaning space S. To communicate with the cleaning space S. Therefore, when the supercritical fluid is supplied from the first communication path 30 to the cleaning space S (in the second communication state), the supercritical fluid is directed toward the central portion of the substrate w disposed in the cleaning space S. Discharged. This supercritical fluid reaches the center of the substrate and then flows in the whole circumferential direction. As a result, the entire substrate can be cleaned by flowing the supercritical fluid along the substrate w. On the other hand, the flow of the supercritical fluid can be reversed by switching the switching means Sw (switching from the second communication state to the first communication state).

  Further, the second communication passage 35 communicates with the cleaning space S at a plurality of locations at intervals in the circumferential direction of the substrate w. Therefore, the flow of the supercritical fluid along the substrate w flows from the entire peripheral direction of the peripheral portion of the substrate w toward the central portion, and from the central portion of the substrate w to the entire peripheral direction of the peripheral portion. It can be reversed with the flow. Therefore, the entire substrate surface is more evenly cleaned.

  Further, the switching means Sw has a simple structure such as first to fourth connecting pipes 13 to 16 having on-off valves 13a to 16a and an on-off control unit C1 for performing on-off control of these on-off valves 13a to 16a. It is possible to reverse the flow in the cleaning space S without changing the direction of the flow of the supercritical fluid flowing through the cleaning space 12.

  In the substrate cleaning method using the substrate cleaning apparatus 10, the substrate surface is cleaned by the vortex of the supercritical fluid formed in the cleaning space S. Further, by switching the switching means Sw, it is possible to reverse the flow of the supercritical fluid in the cleaning space S without changing the direction of the flow of the supercritical fluid flowing through the main flow path pipe 12. For this reason, as described above, the location where the flow is slow or the flow is concentrated when the supercritical fluid flows in one direction in the cleaning space S is moved by the switching, and the resist is moved relative to the substrate surface. The peeling process is performed uniformly, and the generation of scratches on the substrate surface is also suppressed.

  In the above method, the switching means Sw has a simple configuration such as the first to fourth connecting pipes 13 to 16 having the on / off valves 13a to 16a and the on / off control unit C1 for controlling the on / off of the on / off valves 13a to 16a. Thus, as described above, the flow in the cleaning space S can be reversed without changing the direction of the flow of the supercritical fluid flowing through the main flow path pipe 12.

  The substrate cleaning apparatus 10 of the present invention is not limited to the above-described embodiment, and it is needless to say that various changes can be made without departing from the gist of the present invention.

  In the present embodiment, the switching means Sw is composed of the first to fourth connection pipes 13 to 16 each having an opening / closing valve and the opening / closing control unit C1, but is not limited to this. For example, You may comprise by a four-way switching valve and the four-way switching valve control part which controls the said four-way switching valve.

The schematic block diagram of the board | substrate cleaning apparatus which concerns on this embodiment is shown. FIG. 2 is a partially enlarged configuration diagram of a substrate cleaning chamber in the substrate cleaning apparatus according to the embodiment. The partially expanded block diagram in the AA cross section of FIG. 2 is shown. In the substrate cleaning apparatus according to the embodiment, (a) is a diagram showing the flow of the supercritical fluid in the first communication state, and (b) is a diagram showing the flow of the supercritical fluid in the second communication state.

Explanation of symbols

10 Substrate cleaning device 12 Main channel pipe (main channel)
12a One end part 12b Other end part 13 1st connection pipe (1st connection path)
13a 1st on-off valve 14 2nd connection pipe (2nd connection path)
14a Second on-off valve 15 Third connection pipe (third connection path)
15a 3rd on-off valve 16 4th connection pipe (4th connection path)
16a 4th on-off valve 17 Circulation pump (pump)
30 First communication path 35 Second communication path 40 Substrate cleaning chamber C1 Opening / closing control unit S Cleaning space Sw Switching means w Substrate

Claims (6)

A substrate cleaning chamber having a cleaning space for cleaning the substrate with a supercritical fluid;
A main flow path that has a pump for feeding liquid and distributes the supercritical fluid from one end to the other end;
A first communication path communicating with the cleaning space;
A second communication path communicating with the cleaning space;
A first communication state in which one end portion of the main flow path is communicated with the first communication path and the other end portion of the main flow path is communicated with the second communication path, and one end portion of the main flow path is communicated with the second communication path. And a switching means for switching to the second communication state in which the other end portion of the main flow path is communicated with the first communication path. The first communication path communicates with the cleaning space at a position facing a central portion of a substrate disposed in the cleaning space;
The substrate cleaning apparatus according to claim 1, wherein the second communication path communicates with the cleaning space at an outer peripheral portion of a substrate disposed in the cleaning space.   3. The substrate cleaning apparatus according to claim 2, wherein the second communication passage communicates with the cleaning space at a plurality of locations at intervals in a circumferential direction of the substrate. The switching means is
A first connection path having a first on-off valve and connecting one end of the main flow path and the first communication path;
A second connection path having a second on-off valve and connecting one end of the main flow path and the second communication path;
A third connection path having a third on-off valve and connecting the other end of the main flow path and the first communication path;
A fourth connection path having a fourth on-off valve and connecting the other end of the main flow path and the second communication path;
The first communication state in which the first and fourth on-off valves are opened and the second and third on-off valves are closed; the first and fourth on-off valves are closed and the second and third on-off valves are opened 4. The substrate cleaning apparatus according to claim 1, further comprising: an opening / closing control unit that performs opening / closing control of the first to fourth opening / closing valves that are switched to the second communication state. 5. . A substrate cleaning method for cleaning the surface of a substrate by discharging a supercritical fluid supplied from a main flow path into the cleaning space,
A main flow path through which the supercritical fluid flows from one end to the other end; a first communication path and a second communication path respectively communicating with the cleaning space; and each end of the main flow path and the first and first Switching means for switching the communication state with the two communication paths,
A supercritical fluid is supplied from the other end of the main flow path into the cleaning space through the second communication path, and the supercritical fluid is discharged from the cleaning space to the one end of the main flow path through the first communication path. Communication state,
A supercritical fluid is supplied from the other end of the main flow path into the cleaning space through the first communication path, and the supercritical fluid is discharged from the cleaning space to the one end of the main flow path through the second communication path. A substrate cleaning method, wherein the switching means is switched to a communication state. The switching means is
A first connection path having a first on-off valve and connecting one end of the main flow path and the first communication path;
A second connection path having a second on-off valve and connecting one end of the main flow path and the second communication path;
A third connection path having a third on-off valve and connecting the other end of the main flow path and the first communication path;
A fourth connection path having a fourth on-off valve and connecting the other end of the main flow path and the second communication path;
The first communication state in which the first and fourth on-off valves are opened and the second and third on-off valves are closed; the first and fourth on-off valves are closed and the second and third on-off valves are opened The substrate cleaning method according to claim 5, wherein the switching unit is switched between the second communication state and the second communication state.

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