Patent ID: 12204256

DETAILED DESCRIPTION

In the following detailed description, reference is made to the accompanying drawings, which form a part of the description. In the drawings, similar symbols typically identify similar components, unless context dictates otherwise. Furthermore, unless otherwise noted, the description of each successive drawing may reference features from one or more of the previous drawings to provide clearer context and a more substantive explanation of the current exemplary embodiment. Still, the exemplary embodiments described in the detailed description, drawings, and claims are not meant to be limiting. Other embodiments may be utilized, and other changes may be made, without departing from the spirit or scope of the subject matter presented herein. It will be readily understood that the aspects of the present disclosure, as generally described herein and illustrated in the drawings, may be arranged, substituted, combined, separated, and designed in a wide variety of different configurations, all of which are explicitly contemplated herein.

Hereinafter, exemplary embodiments will be described with reference to the accompanying drawings. In the following description, same parts or parts having same functions will be assigned same reference numerals, and redundant description thereof will be omitted.

[Substrate Processing System]

First, referring toFIG.1andFIG.2, a substrate processing system1will be explained. The substrate processing system1shown inFIG.1is a system configured to perform, on a wafer W, formation of a photosensitive film, exposure of the photosensitive film, and development of the photosensitive film. The wafer W as a processing target is, for example, a substrate or a substrate having a film, a circuit, or the like formed thereon as a result of being subjected to a preset processing. The substrate may be, by way of non-limiting example, a silicon wafer. The wafer W (substrate) may have a circular shape. The wafer W may be a glass substrate, a mask substrate, a flat panel display (FPD), or the like. The photosensitive film may be, by way of example, a resist film.

As depicted inFIG.1andFIG.2, the substrate processing system1includes a coating and developing apparatus2(substrate processing apparatus), an exposure apparatus3, and a control device100. The exposure apparatus3is configured to expose a resist film (photosensitive film) formed on the wafer W (substrate). Specifically, the exposure apparatus3radiates an energy beam to an exposure target portion of the resist film by an immersion exposure method or the like.

The coating and developing apparatus2performs a processing of forming the resist film by coating resist (chemical liquid) on a front surface of the substrate W prior to the exposure processing by the exposure apparatus3, and also performs a developing processing of the resist film after the exposure processing. The coating and developing apparatus2is equipped with a carrier block4, a processing block5, and an interface block6.

The carrier block4is configured to carry the wafer W into/from the coating and developing apparatus2. For example, the carrier block4is configured to support a plurality of carriers C for the wafer W, and incorporates therein a transfer device A1including a delivery arm. Each carrier C accommodates therein, for example, a multiple number of circular wafers W. The transfer device A1serves to take out the wafer W from the carrier C, hand the wafer W over to the processing block5, receive the wafer W from the processing block5, and return the wafer W back into the carrier C. The processing block5includes processing modules11,12,13and14.

The processing module11incorporates therein a liquid processing unit U1, a heat treatment unit U2, and a transfer device A3configured to transfer the wafer W to these units. The processing module11is configured to form a bottom film on the front surface of the wafer W by the liquid processing unit U1and the heat treatment unit U2. The liquid processing unit U1is configured to coat, on the wafer W, a processing liquid for forming the bottom film. The heat treatment unit U2is configured to perform various kinds of heat treatments required to form the bottom film.

The processing module12incorporates therein a liquid processing unit U1, a heat treatment unit U2, and a transfer device A3configured to transfer the wafer W to these units. The processing module12is configured to form a resist film on the bottom film by the liquid processing unit U1and the heat treatment unit U2. The liquid processing unit U1is configured to coat, on the bottom film, a processing liquid for forming the resist film. The heat treatment unit U2is configured to perform various kinds of heat treatments required to form the resist film.

The processing module13incorporates therein a liquid processing unit U1, a heat treatment unit U2, and a transfer device A3configured to transfer the wafer W to these units. The processing module13is configured to form a top film on the resist film by the liquid processing unit U1and the heat treatment unit U2. The liquid processing unit U1is configured to coat, on the resist film, a processing liquid for forming the top film. The heat treatment unit U2is configured to perform various kinds of heat treatments required to form the top film.

The processing module14incorporates therein a liquid processing unit U1, a heat treatment unit U2, and a transfer device A3configured to transfer the wafer W to these units. The processing module14is configured to perform a developing processing for the resist film after being subjected to an exposure processing and, also, perform heat treatments required for the developing processing by the liquid processing unit U1and the heat treatment unit U2. The liquid processing unit U1forms a resist pattern by supplying a developing liquid onto the front surface of the wafer W after being subjected to the exposure processing and then washing away this developing liquid with a rinse liquid (that is, performs the developing processing for the resist film). The heat treatment unit U2is configured to perform the various kinds of heat treatments required for the developing processing. Specific examples of these heat treatments include a heat treatment (PEB: Post Exposure Bake) before developing, a heat treatment (PB: Post Bake) after developing, and so forth.

Within the processing block5, a shelf unit U10is provided near the carrier block4. The shelf unit U10is partitioned into a multiple number of cells arranged in a vertical direction. A transfer device A7including an elevating arm is provided near the shelf unit10. The transfer device A7is configured to move the wafer W up and down between the cells of the shelf unit U10.

Within the processing block5, a shelf unit U11is provided near the interface block6. The shelf unit U11is partitioned into a multiple number of cells arranged in the vertical direction.

The interface block6is configured to deliver the wafer W to/from the exposure apparatus3. By way of example, the interface block6incorporates therein a transfer device A8including a delivery arm and is connected to the exposure apparatus3. The transfer device A8serves to hand the wafer W placed in the shelf unit U11over to the exposure apparatus3. The transfer device A8also serves to receive the wafer W from the exposure apparatus3and return it back into the shelf unit U11.

The control device100is configured to control the coating and developing apparatus2partially or in overall. The control device100controls the coating and developing apparatus2to perform a coating and developing processing in the following sequence, for example. First, the control device100controls the transfer device A1to transfer the wafer W within the carrier C to the shelf unit U10, and controls the transfer device A7to place this wafer W in the cell for the processing module11.

Next, the control device100controls the transfer device A3to transfer the wafer W of the shelf unit U10to the liquid processing unit U1and the heat treatment unit U2within the processing module11. Further, the control device100controls the liquid processing unit U1and the heat treatment unit U2to form the bottom film on the front surface of the wafer W. Thereafter, the control device100controls the transfer device A3to return the wafer W with the bottom film formed thereon back into the shelf unit U10, and controls the transfer device A7to place this wafer W in the cell for the processing module12.

Next, the control device100controls the transfer device A3to transfer the wafer W of the shelf unit U10to the liquid processing unit U1and the heat treatment unit U2in the processing module12. Further, the control device100controls the liquid processing unit U1and the heat treatment unit U2to form the resist film on the bottom film of the wafer W. Thereafter, the control device100controls the transfer device A3to return the wafer W back into the shelf unit U10, and controls the transfer device A7to place this wafer W in the cell for the processing module13.

Next, the control device100controls the transfer device A3to transfer the wafer W of the shelf unit U10to each unit within the processing module13. Further, the control device100controls the liquid processing unit U1and the heat treatment unit U2to form the top film on the resist film of the wafer W. Thereafter, the control device100controls the transfer device A3to transfer the wafer W to the shelf unit U11.

Thereafter, the control device100controls the transfer device A8to send the wafer W of the shelf unit U11to the exposure apparatus3. Then, the control device100controls the transfer device A8to receive, from the exposure apparatus3, the wafer W after being subjected to the exposure processing and place the received wafer W in the cell for the processing module14in the shelf unit U11.

Next, the control device100controls the transfer device A3to transfer the wafer W of the shelf unit U11to each unit within the processing module14, and controls the liquid processing unit U1and the heat treatment unit U2to perform a developing processing for the resist film of the wafer W. Then, the control device100controls the transfer device A3to carry the wafer W back into the shelf unit U10, and controls the transfer device A7and the transfer device A1to return this wafer W back into the carrier C.

Through the above-described operations, the coating and developing processing upon the single sheet of wafer W is completed. The control device100controls the coating and developing apparatus2to perform the coating and developing processing for each of the plurality of subsequent wafers W. Here, the specific configuration of the coating and developing apparatus2is not limited to the example described above. The coating and developing apparatus2may be any of various kinds as long as it has a unit configured to perform a heat treatment.

<Heat Treatment Unit>

Now, with reference toFIG.3toFIG.8, an example of the heat treatment unit U2will be described. The heat treatment unit U2is configured to perform a heat treatment including a heating processing and a cooling processing on the wafer W. In the present exemplary embodiment, a configuration of the heat treatment unit U2regarding the heating processing will be explained, while omitting description of a configuration regarding the cooling processing. That is, inFIG.3, etc., illustration of the configuration of the heat treatment unit U2for the cooling processing is omitted.

As depicted inFIG.3, the heat treatment unit U2includes a heat plate20, a plurality of gap members22, a supporting table30, a plurality of heat plate temperature sensors40, an elevating mechanism50, a suction unit70, and the control device100.

The heat plate20is configured to place the wafer W thereon and heat the wafer W placed thereon. The heat plate20is configured to receive heat from a heater21(heating mechanism) and maintain a high temperature through heat conduction by a solid. The heat plate20may be composed of a material containing, for example, silicon carbide. The heat plate20has a disk shape and incorporates a plurality of heaters21therein. The heat plate20has an area equal to or larger than that of the wafer W when viewed from the top. A multiple number of through holes20zare formed through the heat plate20in a thickness direction thereof. These through holes20zare arranged to correspond to a multiple number of elevating pins51(to be described later), and serve as passages through which the elevating pins51pass when they are moved up and down.

The plurality of gap members22are formed along a front surface20aof the heat plate20on which the wafer W is placed. The gap members22are proximity pins configured to support the wafer W to form a clearance V between the heat plate20and the wafer W. The plurality of gap members22are interspersed along the front surface20aof the heat plate20. The heights of these gap members22from the front surface20aof the heat plate20to their leading ends in contact with the wafer W may be all same.

In addition, although the heat plate20is shown to have a flat shape inFIG.3, the heat plate20is actually formed in a concave shape so that it may be inclined downwards as it goes from an outer side toward an inner side (seeFIG.4).FIG.4is a diagram illustrating details of the shape of the heat plate20.

As illustrated inFIG.4, the front surface20aof the heat plate20on which the wafer W is placed has a concave region20dthat is inclined downwards as it goes from an edge (outer side) toward a center (inner side) thereof. In the heat plate20according to the present exemplary embodiment, approximately the entire front surface20ais formed as the concave region20d, and an edge portion20eis the most upwardly protruding region, whereas a central portion20cis the most downwardly protruding region. That is, in the heat plate20, the most downwardly protruding region of the concave region20dis the region (central portion20c) facing a central portion Wc of the wafer W in the state that the wafer W is placed on the heat plate20. More specifically, in the front surface20aof the heat plate20, an outermost edge (outer side than the edge portion20eof the concave region20d) is formed as a flat portion20f. Here, however, the flat portion20fmay not be provided, and a curved surface of the concave region20dmay be extended up to the outermost edge of the heat plate20. According to this configuration, a heating effect at an edge portion of the wafer W can be improved. The shape of the front surface20awhere the concave region20dis formed is, for example, a spherical surface (curved surface), and the curvature thereof may or may not be constant. When the curvature of the concave region20dis not constant, the inner curvature of the concave region20dmay be set to be larger than the outer curvature thereof (so that the inner side may be deeper). According to this configuration, when the bending of the wafer W is not uniform, for example, a state in which a gap between the wafer W and the heat plate20on the outer side is narrower than a gap on the inner side can be created more easily when suction is performed, thus making it easier to suction the wafer W having various bending states. That is, the robustness of the suction with respect to the bending of the wafer W can be improved.

In the example shown inFIG.4, the wafer W is a concave wafer (a substrate bent in + direction) in which a region of the central portion Wc protrudes more downwardly than the edge portion We. However, the wafer W placed on the heat plate20is not limited to the concave wafer, but it can be a flat wafer, or a convex wafer (a substrate bent in − direction) in which the region of the central portion We protrudes higher than the edge portion We. In consideration of the fact that wafers W having such various shapes may be placed, it is desirable to use the heat plate20having the above-described downwardly inclined concave region20d. The reason for this will be described with reference toFIG.5AandFIG.5B.

FIG.5Ais a diagram illustrating an example where a convex wafer W is placed on a flat heat plate200according to a comparative example, andFIG.5Bis a diagram illustrating an example where a concave wafer W is placed on the flat heat plate200according to the comparative example. As shown inFIG.5A, in case of the convex wafer W, the edge portion We is placed on the gap members22on the edge side of the heat plate200having the flat shape. In this way, if the edge portion We of the wafer W is appropriately placed on the gap members22, this state is as if a suction area is covered with the wafer W. Therefore, the wafer W can be properly attracted in the direction of the heat plate200by the suction of the suction unit70. As for the convex wafer W and the flat-plate shape wafer W, in the heat plate20(seeFIG.4) having the concave region20daccording to the present exemplary embodiment as well, the edge portion We of the wafer W can be appropriately placed on the gap members22on the edge side. Therefore, the wafer W can be properly attracted in the direction of the heat plate20by the suction of the suction unit70.

Meanwhile, as shown inFIG.5B, in case of the concave wafer W, the edge portion We is not placed on the gap members22on the edge side of the heat plate200but it is in a floating state. In this case, the state as if being covered with the wafer W cannot be created, so that the atmosphere may be easily sucked from the edge portion We side, and airtightness is difficult to achieve. As a result, attraction property of the wafer W to the heat plate200is lowered. As described above, while the shape of the heat plate is not a critical factor for the convex wafer W or the flat-plate shape wafer W from the viewpoint of the attraction property of the wafer W, the attraction property of the wafer W cannot be guaranteed on the flat heat plate200if the wafer W has the concave shape. From this point of view, in a situation where wafers W of various shapes can be placed, it is desirable that the heat plate is formed to have a shape enabling to improve the attraction property of the concave wafer W. As described above, in the placement of the concave wafer W on the heat plate, the problem is that the edge portion We is not placed on the gap members22but is in the floating state. As a resolution, the above-described heat plate20is adopted as a heat plate that allows the edge portion We to be securely placed on the gap members22. That is, by using the heat plate20having the concave region20dthat is inclined downwards as it goes from the edge side toward the center side, the shape of the concave wafer W and the shape of the heat plate20can be easily matched, so that the edge portion We of the wafer W can be appropriately placed on the gap members22. As a consequence, even for the concave wafer W, the attraction property for the heat plate20can be improved.

A depth d1of the concave region20dof the heat plate20is set to exceed a bending amount of the concave wafer W at least. The depth d1is a length in a height direction from the flat portion20fas a reference plane to the central portion20c, as shown inFIG.4. The bending amount of the wafer W is a length in the height direction from the edge portion We of the wafer W to the central portion We thereof.

The shape of the concave region20dof the heat plate20is decided as follows, for example. Assume that the concave wafer W has a diameter of 300 mm and a bending amount of 1000 μm. In this case, the radius of curvature of this wafer W is calculated as 11250.5 mm from the square root theorem. In addition, in case that a film is uniformly formed on the wafer W, the wafer W is deformed due to a difference in the linear expansion. If a cross-sectional shape of the wafer W is measured, the diameter, the bending amount and the radius of curvature meet the above-described relationship. Then, based on the radius of curvature of the wafer W, the radius of curvature of the concave region20dof the heat plate20is determined. Specifically, the radius of curvature of the concave region20dis calculated by adding a thickness of the wafer W and a height of the gap member22protruding from the front surface20ato the radius of curvature (11250.5 mm) of the wafer W.

In addition, the depth d1and the diameter ϕ of the concave region20dof the heat plate20are set in consideration of a positional deviation in a robot transfer or the like as well as the size of the wafer W. To elaborate, when a transfer error of about 2 mm is taken into consideration, the depth d1of the concave region20dmay be set to be about 1 mm, and the diameter ϕ thereof may be set to be about 304 mm. Moreover, even when the aforementioned transfer error arises, the influence upon the temperature uniformity of the wafer in the heat treatment is small.

The concave region20dof the heat plate20whose shape is decided as described above can be formed by, for example, a rotary grinding machine or the like. When a process defect due to microparticles generated from the surface of the heat plate after being machined is expected, the risk of particle scattering can be reduced by performing brush polishing or annealing treatment.

Returning back toFIG.3, the suction unit70attracts the wafer W toward the heat plate20by applying a suction force to the wafer W. The suction unit70applies the suction force to a plurality of regions in a rear surface of the wafer W. The suction unit70has a suction device71and a plurality of pipelines72.

The suction device71is a mechanism configured to suck up a gas by the action of pressure. Each of the plurality of pipelines72is connected at one end to the suction device71, and the other end thereof reaches an attraction hole20x(a portion facing the wafer W) formed in the front surface20aof the heat plate20.

The supporting table30has a base plate31and a peripheral wall32(supporting member). The supporting table30may be made of a material containing stainless steel, for example. The peripheral wall32is provided along the periphery of the base plate31and supports a peripheral portion of the heat plate20. The base plate31faces the heat plate20, and supports the heat plate20from below with the peripheral wall32therebetween. In the state that the peripheral wall32supports the heat plate20, a cavity33is formed in a space surrounded by the supporting table30. A plurality of path holes31zthrough which the elevating pins51(to be described later) pass are formed in the base plate31. The plurality of path holes31zare arranged to correspond to the multiple number of elevating pins51, and serve as passages for the elevating pins51when they are moved up and down.

The plurality of heat plate temperature sensors40are individually provided at different positions within the heat plate20. These heat plate temperature sensors40measure temperatures near the heaters21, and transmit the measurement results to the control device100.

Separately from the plurality of heat plate temperature sensors40, a plurality of control temperature sensors140may be provided inside the heat plate20so as to correspond to different positions of the wafer W.FIG.6is a diagram illustrating the layout of the plurality of control temperature sensors140. As shown inFIG.6, it is desirable that a distance of each of the plurality of control temperature sensors140provided inside the heat plate20from the front surface20aof the heat plate20is as short as possible. Specifically, it is desirable that the distance of the control temperature sensor140from the front surface20ais set to be uniform as being about 1 mm to 3 mm. In addition, the plurality of control temperature sensors140are arranged so that lengths d2in a height direction (vertical direction) from upper ends140a(leading ends) thereof to the front surface20aof the heat plate20are all same.

FIG.7Ais a chart showing a temperature control based on temperatures acquired by the control temperature sensor140that is relatively close in distance from the front surface20aof the heat plate20, andFIG.7Bis a chart showing a temperature control based on temperatures acquired by the control temperature sensor140which is far from the front surface20a. InFIG.7AandFIG.7B, a horizontal axis represents time, and a vertical axis represents a temperature acquired by the control temperature sensor140. As shown inFIG.7AandFIG.7B, the closer the control temperature sensor140is to the front surface20a, the more rapidly a temporary temperature drop after the wafer W is mounted on the heat plate20is obtained. Thus, since a temperature raising control for the heater21can be started early, control responsiveness can be improved, and temperature optimization for the heat treatment can be achieved at an early stage. When the distances of the control temperature sensors140from the front surface20aare different from each other, the time required to achieve the temperature optimization for the heat treatment becomes different therebetween, as can be seen fromFIG.7AandFIG.7B. In this case, conditions for the heat treatment may become different for each area of the wafer W corresponding to each control temperature sensor140. In this case, there is a risk that the uniformity of the heat treatment of the wafer W may be deteriorated. As a resolution, by setting the length d2of the temperature control sensors140in the height direction (vertical direction) up to the front surface20ato be uniform as stated above, the uniformity of the heat treatment of the wafer W can be improved. In this way, the temperature of the heat plate20is controlled based on the temperature acquired by the control temperature sensor140which is located closer to the front surface20aof the heat plate20than the heat plate temperature sensor40near the heater21and whose distance from the front surface20ais set to a predetermined value. As a consequence, it is possible to carry out the heat treatment more suitable for the temperature distribution of the wafer W. In addition, this control method is deemed to be desirable as a method suitable for the temperature distribution of the wafer W even for a configuration in which the distance from each heater21to the front surface20ais different at individual positions, such as when the heaters21are provided approximately horizontally with respect to the front surface20ahaving a curved surface or a step.

Referring back toFIG.3, the elevating mechanism50has the multiple number of (for example, three) elevating pins51, and a driving unit52. The elevating pin51is moved up and down through the path hole31zof the base plate31and the through hole20zof the heat plate20. An upper portion of the elevating pin51is protruded above the heat plate20as the elevating pin51is raised, and is accommodated within the heat plate20as the elevating pin51is lowered. The driving unit52incorporates therein a driving source such as a motor and an air cylinder, and serves to move the elevating pins51up and down. The elevating mechanism50moves the elevating pins51up and down, thus allowing the wafer W on the heat plate20to be moved up and down. Here, from the viewpoint of improving the effect of attraction when the wafer W is suctioned toward the heat plate20by the suction unit70, it is desirable that the path hole31zof the elevating pin51or the like is blocked with respect to a space below the base plate31. Hereinafter, with reference toFIG.8, an example of a configuration of a seal member according to the blocking of the path hole31zor the like will be explained.

FIG.8is a diagram schematically illustrating an example of the configuration of the seal member. InFIG.8, illustration of the concave region20dof the heat plate20, etc., is omitted. As shown inFIG.8, the heat treatment unit U2includes an upper seal member91and a lower seal member92as components of the seal member. The upper seal member91is made of a cylindrical heat insulating material, and is provided so as to be in contact with a surface (bottom surface) of the heat plate20opposite to the front surface20a. The upper seal member91is provided so as to surround the elevating pin51. The upper seal member91has elasticity and is made of a material including, for example, resin or rubber. In addition, a heating resistor93may be provided in the substantially entire bottom surface of the heat plate20.

The lower seal member92is configured to close the internal space of the path hole31zof the base plate31and the internal space of the upper seal member91with respect to the space below the base plate31. The lower seal member92is made of, for example, polyimide or PEEK. For example, the lower seal member92is provided on a bottom surface of the base plate31, as shown inFIG.8. Since the lower seal member92is disposed below the base plate31, a heating effect on the wafer W, which is a problem caused when the lower seal member92with heat is positioned above it, is suppressed. In addition, by separating the lower seal member92from the heat source, durability of the lower seal member92can be improved, and maintenability of the lower seal member92can be improved. Further, the lower seal member92may be provided inside the base plate31.

If a member having elasticity is not used as the upper seal member91, a spring configured to press the upper seal member91from below may be further provided between the upper seal member91and the lower seal member92. Such a spring may be provided on a holder on the base plate31, for example.

The control device100serves to control the heaters21based on the temperatures detected by the plurality of control temperature sensors140, control the driving unit52of the elevating mechanism50, and control the transfer device A3to perform the transfer of the wafer W from the heat plate20. Further, the control device100also performs a control over a suctioning process by the suction device71, and so forth.

The control device100is composed of one or more control computers. The control device100has, for example, a circuit120shown inFIG.9. The circuit120includes one or more processors122, a memory124, a storage126, an input/output port128, and a timer132. The storage126has a computer-readable recording medium such as, but not limited to, a hard disk. The recording medium stores therein a program for causing the control device100to perform a substrate processing method to be described later. The recording medium may be a portable medium such as a nonvolatile semiconductor memory, a magnetic disk, or an optical disk.

The memory124temporarily stores the program loaded from the recording medium of the storage126and an operation result by the processor122. The processor122executes the program in cooperation with the memory124. The input/output port128performs input/output of electric signals between the liquid processing unit U1and the heat treatment unit U2in response to an instruction from the processor122. The timer132measures an elapsed time by counting a reference pulse of a certain cycle, for example.

[Operations]

In general, the flat heat plate200shown inFIG.5AandFIG.5Bis used as the heat plate. In this heat plate200, when the concave wafer W (seeFIG.5B) whose inner region protrudes downwards more than the outer region thereof is used in particular, it is difficult to appropriately attract the outer region of the wafer W even by suctioning the wafer W with the suction unit70. Since the outer region of this wafer W having the concave shape is in the floating state (seeFIG.5B), the atmosphere may be easily sucked in and it is difficult to easily achieve the airtightness. For this reason, even when compared with, for example, the convex substrate (seeFIG.5A) whose inner region protrudes upwards, the attraction property with respect to the heat plate200is deteriorated.

FIG.10is a diagram showing an example of a VAC flow rate (vacuum rate of the suction unit70) required for each wafer bending amount. InFIG.10, a horizontal axis indicates a wafer bending amount, and a vertical axis represents a vacuum rate required for correcting the bending. In addition, inFIG.10, a solid line indicates the vacuum rate for each bending amount of the wafer W having the convex shape, and a dashed line indicates the vacuum rate for each bending amount of the wafer W having the concave shape. As shown inFIG.10, the vacuum rate is found to be particularly high in the concave wafer W. By way of example, the vacuum rate for the wafer W having the bending mount of about 1000 μm is found to be about 50 times as large as the vacuum rate of the wafer W having the bending amount of about 200 μm. Thus, the method of increasing the vacuum rate for the sake of improving the attraction property of the wafer W goes against the sustainable society, and thus cannot be said to be advantageous. In addition, the increase of the vacuum rate raises a concern that a local cool spot may be generated at an inlet portion, or that scratches and particles may be generated on the rear surface of the wafer W due to an increase of an attraction pressure. For this reason, there is a demand for device configured to increase the attraction property of the concave wafer W to the heat plate through a method other than increasing the vacuum rate.

In this regard, in the heat treatment unit U2according to the present exemplary embodiment, since the heat plate20has the concave region20dinclined downwards as it goes from the outer side toward the inner side, it is easy to make the shape of the concave wafer W conform to the shape of the heat plate20(specifically, the concave region20dof the heat plate20). With this configuration, when the wafer W is suctioned by the suction unit70, the outer region of the concave wafer W can also be appropriately attracted to the heat plate20. Since the wafer W can be properly attracted to the heat plate20in this way, the wafer W can be appropriately supported by the gap members22, so that the heat treatment can be uniformly performed on the substrate at any regions thereof. As described above, according to the heat treatment unit U2of the present exemplary embodiment, the attraction property of the wafer W in the heat treatment can be improved, so that the uniformity of the heat treatment can be improved.

The effect of improving the uniformity of the heat treatment will be described in comparison with the heat plate200according to the comparative example.FIG.11AandFIG.11Bare diagrams illustrating a wafer temperature range with respect to the heat plate200according to the comparative example.FIG.12AandFIG.12Bare diagrams illustrating a wafer temperature range with respect to the heat plate20according to the present exemplary embodiment. Here, the wafer temperature range refers to information on a temperature range between a plurality of positions on the front surface20aof the heat plate20obtained as a result of performing evaluation by using temperature sensors attached to those different positions. InFIG.11AandFIG.12A, an actual temperature difference value is shown as the wafer temperature range, and inFIG.11BandFIG.12B, the degree of the temperature difference is expressed in percentage (%) as the wafer temperature range. The result that the degree of the temperature difference is 0% indicates that there is no temperature difference at all. InFIG.11BandFIG.12B, a horizontal axis represents a temperature transition during the heating of the wafer W, and a vertical axis represents a wafer temperature and a wafer temperature range. InFIG.11BandFIG.12B, a solid line represents a temperature near the center of the wafer W; a dashed-dotted line represents a temperature near the edge (outer periphery) of the wafer W; and a dashed line represents a wafer temperature range. In addition, the temperatures shown inFIG.11AandFIG.11BandFIG.12AandFIG.12Bare measured by a total of five thermocouples (not shown) respectively attached to the central portion of the wafer W and four edge portions distanced apart from each other by 90 degrees with respect to the central portion. In addition, the temperature indicated by the solid line is a temperature acquired by the thermocouple of the central portion, and the temperature indicated by the dashed-dotted line is the average of the temperatures acquired by the thermocouples of the four edge portions. As the wafer W, the concave wafer having the bending amount of 1000 μm is used.

As can be seen fromFIG.11A, in the heat plate200according to the comparative example, a temperature difference between the temperature near the center of the wafer W and the temperature near the edge of the wafer W is found to be 62.4° C. in a transient state. Further, in a steady state (for example, after the lapse of 120 seconds), the temperature difference is found to be 6.5° C. As shown inFIG.11B, the wafer temperature range (the degree of the temperature difference between the central portion and the edge portions) does not reach 0% even when 120 seconds has elapsed. As described above, in the heat plate200according to the comparative example, the temperature difference between the inner side and the outer side of the wafer W is large, and even if a heating time is lengthened, the temperature difference is still generated in the surface of the wafer W, so it cannot be said that the uniformity of the heat treatment is achieved.

Meanwhile, in the heat plate20according to the present exemplary embodiment, the temperature range obtained by providing the control temperature sensors140at the multiple positions of the wafer W, the same as described above, is 0.5° C., as shown inFIG.12A. As can be clearly seen from this point, the temperature difference is improved by about 125 times as compared to the heat plate200according to the comparative example. Further, in a steady state (for example, after the lapse of 60 seconds), the temperature difference is found to be 0.1° C., which is improved by about 65 times as compared to the heat plate200according to the comparative example. Further, as shown inFIG.12B, the wafer temperature range (the degree of the temperature difference between the central portion and the edge portions) is maintained at around 0% from an early stage. As stated above, in the heat plate20according to the present exemplary embodiment, since the temperature difference between the inner side and the outer side of the wafer W is suppressed to be small from the early stage, it can be said that the uniformity of the heat treatment is improved.

The most downwardly protruding portion of the concave region20dmay face the central portion We of the wafer W in the state that the wafer W is placed on the heat plate20. According to this configuration, the shape of the heat plate20can be more easily made to conform to the shape of the concave wafer W, so that the attraction property of the wafer W can be improved.

The heights of the plurality of gap members22from the front surface20aof the heat plate20to the leading ends thereof which are in contact with the wafer W may be set to be all same. According to this configuration, it is possible to suppress deterioration of the correspondence between the shape of the concave wafer W and the shape of the heat plate20that might be caused by being affected by the gap members22.

The heat treatment unit U2is further equipped with the plurality of control temperature sensors140provided inside the wafer W to correspond to the different positions of the wafer W and configured to measure the temperatures for use in controlling the heaters21. These control temperature sensors140may be arranged such that their lengths in the height direction from the leading ends thereof to the front surface20aof the heat plate20are all same. With this configuration, the temperatures for use in the control of the heaters21are acquired under the same conditions (conditions under which the distance from the front surface20aof the heat plate20becomes uniform) for the different positions of the wafer W. Therefore, the uniformity of the heat treatment of the wafer W can be improved.

The heat treatment unit U2is equipped with the base plate31configured to support the heat plate20from below with the peripheral wall32therebetween and having the path holes31zthrough which the elevating pins51pass. Further, the heat treatment unit U2is equipped with the upper seal member91which is made of the cylindrical heat insulating material and is in contact with the bottom surface of the heat plate20opposite to the front surface20a. In addition, the heat treatment unit U2is equipped with the lower seal member92configured to close the internal space of the path hole31zof the base plate31and the internal space of the upper seal member91with respect to the space below the base plate31. In this way, the internal space of the path hole31z(the hole through which the elevating pin51passes) of the base plate31is closed by the lower seal member92with respect to the space below the base plate31. Therefore, the suction effect (vacuum correction effect for the bent wafer) can be improved when the wafer W is sucked toward the heat plate20by the suction unit70. Here, if only the above-described closing effect is required, it may be also possible that the seal member is not divided into the upper seal member91and the lower seal member92but is just composed of only one member. However, if the seal member composed of the only one member is provided at a position near the heat plate20, for example, the seal member may be gradually degraded due to the thermal deterioration. According to the present exemplary embodiment, however, the seal member is divided into the upper seal member91and the lower seal member92, and the upper seal member91made of the heat insulating material that does not interfere with the heat treatment of the heat plate20is provided at the position in contact with the heat plate20. Further, the lower seal member92is provided at the position away from the heat plate20(a position not affected by the heat of the heat treatment). Thus, it is possible to avoid the gradual deterioration of the seal member, while enabling to perform the heat treatment by the heat plate20appropriately.

The lower seal member92may be provided within the base plate31or on the bottom surface of the base plate31. According to this configuration, the internal space of the path hole31zof the base plate31can be securely closed against the space below the base plate31with the lower seal member92.

The upper seal member91may have elasticity. According to this configuration, it is possible to improve the contact between the upper seal member91and the heat plate20while providing a certain degree of freedom in the vertical direction for the position of the upper seal member91.

So far, the various exemplary embodiments have been described. However, the present disclosure is not limited to the above-described exemplary embodiments, and various additions, omissions, replacements, and modifications may be made. Further, by combining the components in the various exemplary embodiments, other exemplary embodiments may be conceived.

By way of example, in the configuration in which the control device100controls the driving unit52to move the elevating pins51up and down, the control device100may control the driving unit52to change the descending speed of the elevating pin51during the descending operation.

FIG.13is a diagram for describing the descending speed of the elevating pin51according to a modification example.FIG.13shows an example of the speed of the elevating pin51in the descending operation of the elevating pin51. In the example shown inFIG.13, the descending operation of the elevating pin51is performed at a descending speed of 30 mm/s from a descending operation starting position600of the elevating pin51(that is, UP completion position of the elevating pin51) up to a temporary stop position601. Then, after the descending is stopped at the temporary stop position601for a preset time period, the descending operation of the elevating pin51is performed again at a descending speed of 2 mm/s from the temporary stop position601to a under-gap position602below the leading end of the gap member22. In this case, the wafer W is placed on the gap member22at the descending speed of 2 mm/s. Finally, the descending operation of the elevating pin51is performed at a descending speed of 10 mm/s from the under-gap position602to a descending operation end position603(that is, DOWN completion position of the elevating pin51).

That is, in the descending operation, the control device100controls the driving unit52to lower the elevating pin51at a first predetermined speed (for example, 30 mm/s) down to a predetermined first height (the aforementioned temporary stop position601). Further, when the elevating pin51is further lowered from the first height, the control device100controls the driving unit52to lower the elevating pin51at a second speed (for example, 2 mm/s) that is lower than the first speed.

Then, in the descending operation, the control device100controls the driving unit52such that the elevating pin51that has reached the predetermined first height (the aforementioned temporary stop position601) is stopped for a preset time period without being moved down.

The above-described control by the control device100is a control for suppressing large deformation of the wafer W immediately after the wafer W is mounted on the heat plate20. For example, such a large deformation of the wafer W occurs as a balance in a surface tension of the wafer W is changed due to partial expansion of the wafer W when only the edge portion (outer periphery) of the wafer W is extremely heated, for example. In case that the wafer W has, for example, the convex shape, the edge portion of the wafer W may be easily heated first, so that the above-described large deformation is likely to occur.

Since the driving unit52is controlled by the control device100such that the descending speed after the first height becomes lower than the descending speed up to the first height, the rapid heating of the edge portion of the wafer W is suppressed when the wafer W having the convex shape is mounted on the heat plate20. Thus, the large deformation of the wafer W, which becomes the problem caused when the edge portion of the wafer W is extremely heated, can be suppressed.

In addition, since the driving unit52is controlled by the control device100such that the elevating pin51is stopped at the predetermined first height for the preset time period, the rapid heating of the edge portion of the wafer W is suppressed when the wafer W having the convex shape is mounted on the heat plate20. Therefore, it is possible to more appropriately suppress the wafer W from being largely deformed.

Moreover, the control device100may determine the aforementioned first height based on bending amount data of the wafer W. In this case, the substrate processing apparatus may be further equipped with an inspection unit U3(seeFIG.14) having a periphery imaging sub-unit400(measuring unit) configured to measure the bending amount data of the wafer W.

FIG.14is a side view of the inspection unit U3according to a modification example. The bending amount data of the wafer W is measured by the inspection unit U3shown inFIG.14. First, the control device100controls the individual components of the substrate processing apparatus to transfer the wafer W to the inspection unit U3. Then, the control device100controls a rotating/holding sub-unit900to hold the wafer W on a holding table901. Next, the control device100controls the rotating/holding sub-unit900, causing the holding table901to be moved to a predetermined imaging position along a guide rail904by an actuator903.

Next, the control device100controls the rotating/holding sub-unit900to allow the holding table901to be rotated by the actuator903. As a result, the wafer W is rotated. In this state, the control device100controls the periphery imaging sub-unit400to perform the imaging with a camera410while turning on a light source of a lighting module420. As a result, an end surface of the wafer W is imaged along the entire circumference of the wafer W. The obtained images of the end surface of the wafer W are used as the bending amount data for specifying the bending amount of the wafer W.

The control device100calculates a profile line of the wafer W based on the obtained images of the end surface of the wafer W. Specifically, the control device100identifies upper and lower edges of the end surface of the wafer W from the obtained images based on, for example, a contrast difference. Then, the control device100calculates a line passing through a midway position between the upper edge and the lower edge as the profile line. The control device100calculates the bending amount of the wafer W by subtracting a profile line of a reference wafer (a wafer whose bending amount is known) from the calculated profile line.

Then, the control device100determines the aforementioned first height in consideration of the bending amount of the wafer W calculated based on the bending amount data. In this way, since the first height, which is a speed change point, is determined in consideration of the actual bending amount of the wafer W, the rapid heating of the edge portion of the wafer W can be suppressed more appropriately in consideration of the actual shape of the wafer W.

In addition, the bending amount data of the wafer W may not necessarily be measured by the inspection unit U3. The bending amount data of the wafer W may be, for example, data previously measured by another apparatus to be stored in the substrate processing apparatus.

FIG.15Ais a plan view of a heat plate520according to another modification example, andFIG.15Bis a cross sectional view taken along a line b-b ofFIG.15A. As depicted inFIG.15AandFIG.15B, a surface height of an outer peripheral region652of the heat plate520may be lower than a surface height of an inner region651. According to this configuration, when the wafer W having the convex shape is placed on the heat plate520, the rapid heating of the edge portion of the wafer W that might be caused when the edge portion of the wafer W collides with the outer peripheral region652of the heat plate520can be suppressed, so that the large deformation of the wafer W can be suppressed.

A difference in the surface height between the outer peripheral region652and the inner region651may be smaller than 0.2 mm (e.g., about 0.1 mm). In case that the wafer W of the flat shape without having irregularities is placed on the heat plate520, when the difference in the surface height between the outer peripheral region652and the inner region651is large, there is a risk that the heat treatment may not be appropriately performed. In this regard, by setting the difference in the surface height between the outer peripheral region652and the inner region651to be less than 0.2 mm, the heat treatment can be carried out appropriately even when the flat wafer W is placed on the heat plate520.

Furthermore, as shown inFIG.15A, fixed pins722may be provided as gap members near a boundary between the outer peripheral region652and the inner region651to support the wafer W. In the example shown inFIG.15A, twenty four fixed pins722are provided over the entire circumference of the boundary. As described above, since the fixed pins722are provided near the boundary between the outer peripheral region652and the inner region651, the edge portion of the wafer W having the convex shape can be more appropriately suppressed from colliding with the outer peripheral region652.

In addition, the surface height of the outer peripheral region652may be set to be uniform (constant height without variations) over the whole region. Therefore, the heat treatment upon the edge portion of the wafer W can be performed suitably.

Moreover, as shown inFIG.15AandFIG.15B, in the outer peripheral region652, fixed pins723which support the wafer W may be further provided as gap members. With this configuration, it is possible to more appropriately suppress the edge portion of the wafer W having the convex shape from colliding with the outer peripheral region652. Also, as shown inFIG.15B, the height of the fixed pin723may be higher than that of the outer peripheral region652and lower than that of the inner region651.

Here, various exemplary embodiments included in the present disclosure are described in [E1] to [E16] below.

[E1]

A substrate processing apparatus includes a heat plate configured to place a substrate thereon and heat the substrate placed thereon; and multiple gap members formed along a front surface of the heat plate on which the substrate is placed, and configured to support the substrate to secure a clearance between the heat plate and the substrate. Further, the substrate processing apparatus includes a suction unit configured to suck the substrate toward the heat plate; and an elevating pin configured to penetrate the heat plate and configured to be moved up and down to move the substrate placed on the heat plate up and down. The front surface of the heat plate of the substrate processing apparatus has a concave region inclined downwards from an outer side toward an inner side thereof.

[E2]

The substrate processing apparatus described in [E1],wherein a most downwardly protruding portion of the concave region faces a central portion of the substrate in a state that the substrate is placed on the heat plate.
[E3]

The substrate processing apparatus described in [E1] or [E2],wherein the multiple gap members are same in a height from the front surface of the heat plate on which the multiple gap members are provided to leading ends thereof, the leading ends being in contact with the substrate.
[E4]

The substrate processing apparatus described in any one of [E1] to [E3],wherein the heat plate is a plate-shaped member configured to receive heat from a heating mechanism and maintain a high temperature by heat conduction through a solid, and the heat plate has an area equal to or larger than that of the substrate when viewed from a top,the substrate processing apparatus further includes multiple temperature sensors provided within the heat plate to respectively correspond to different positions of the substrate and configured to measure a temperature to control the heating mechanism, andthe multiple temperature sensors are arranged such that lengths of these temperature sensors in a height direction from leading ends thereof to the front surface of the heat plate are equal.
[E5]

The substrate processing apparatus described in any one of [E1] to [E4], further including:a base plate, configured to support the heat plate from below with a supporting member therebetween, having a path hole through which the elevating pin passes;an upper seal member made of a cylindrical heat insulating material and in contact with a bottom surface of the heat plate opposite to the front surface; anda lower seal member configured to close an internal space of the path hole of the base plate and an internal space of the upper seal member with respect to a space below the base plate.
[E6]

The substrate processing apparatus described in [E5],wherein the lower seal member is provided within the base plate or provided on a bottom surface of the base plate.
[E7]

The substrate processing apparatus described in [E5] or [E6],wherein the upper seal member has elasticity.
[E8]

The substrate processing apparatus described in any one of [E1] to [E7], further including:a driving unit configured to move the elevating pin up and down; anda control device configured to control the driving unit to move the elevating pin up and down,wherein the control device controls the driving unit to change a descending speed of the elevating pin in a descending operation of the elevating pin.
[E9]

The substrate processing apparatus described in [E8],wherein the control device controls the driving unit such that the elevating pin is lowered at a predetermined first speed up to a preset first height, and such that the elevating pin is lowered at a second speed lower than the first speed when the elevating pin is further lowered from the first height.
[E10]

The substrate processing apparatus described in [E9],wherein the control device controls the driving unit such that, in the descending operation, the elevating pin that has reached the first height is stopped for a preset time period without being lowered.
[E11]

The substrate processing apparatus described in [E9] or [E10],wherein the control device decides the first height based on bending amount data of the substrate.
[E12]

The substrate processing apparatus described in [E11], further including:a measuring unit configured to measure the bending amount data of the substrate.
[E13]

The substrate processing apparatus described in any one of [E1] to [E12],wherein a surface height of an outer peripheral region of the heat plate is lower than a surface height of an inner region thereof.
[E14]

The substrate processing apparatus described in [E13],wherein a difference in the surface height between the outer peripheral region and the inner region is less than 0.2 mm.
[E15]

The substrate processing apparatus described in [E13] or [E14],wherein the multiple gap members have fixed pins provided near a boundary between the outer peripheral region and the inner region to support the substrate.
[E16]

The substrate processing apparatus described in any one of [E13] to [E15],wherein the surface height of the outer peripheral region is uniform.

According to the exemplary embodiment, it is possible to provide the substrate processing apparatus capable of improving the uniformity of the heat treatment by bettering the attraction property of the substrate in the heat treatment.

From the foregoing, it will be appreciated that various embodiments of the present disclosure have been described herein for purposes of illustration, and that various modifications may be made without departing from the scope and spirit of the present disclosure. Accordingly, the various embodiments disclosed herein are not intended to be limiting. The scope of the inventive concept is defined by the following claims and their equivalents rather than by the detailed description of the exemplary embodiments. It shall be understood that all modifications and embodiments conceived from the meaning and scope of the claims and their equivalents are included in the scope of the inventive concept.

The claims of the present application are different and possibly, at least in some aspects, broader in scope than the claims pursued in the parent application. To the extent any prior amendments or characterizations of the scope of any claim or cited document made during prosecution of the parent could be construed as a disclaimer of any subject matter supported by the present disclosure, Applicants hereby rescind and retract such disclaimer. Accordingly, the references previously presented in the parent applications may need to be revisited.