阅读说明：本技术 平坦度控制方法及装置、涂膜的形成方法及装置 (Flatness control method and device, and method and device for forming coating film ) 是由 荻原勤 于 2021-04-23 设计创作，主要内容包括：本发明提供一种平坦度控制方法及装置、涂膜的形成方法及装置。本发明的平坦度控制方法,用于晶圆的平坦度控制,其包含以下步骤：准备具有包含多个区段的固持面,且该多个区段各自具备干式粘接性纤维构造物的固持构件的步骤；使晶圆吸附于该固持构件的该固持面,而使该晶圆固持于该固持构件的步骤；测量该晶圆的平坦度,而取得该晶圆的平坦度的信息的步骤；及基于该平坦度的信息,而在该固持构件的该固持面的该多个区段的一部分中,释放该干式粘接性纤维构造物对该晶圆所进行的吸附的步骤。(The invention provides a flatness control method and device, and a method and device for forming a coating film. The flatness control method of the invention is used for controlling the flatness of the wafer, and comprises the following steps: preparing a holding member having a holding surface including a plurality of segments each having a dry-adhesive fibrous structure; a step of attaching a wafer to the holding surface of the holding member to hold the wafer on the holding member; measuring the flatness of the wafer to obtain the flatness information of the wafer; and releasing the wafer from being adsorbed by the dry adhesive fibrous structure in a part of the plurality of sections of the holding surface of the holding member based on the flatness information.)

1. A flatness control method for controlling the flatness of a wafer includes the following steps:

preparing a holding member having a holding surface including a plurality of segments each having a dry-adhesive fibrous structure;

a step of attaching a wafer to the holding surface of the holding member to hold the wafer on the holding member;

measuring the flatness of the wafer to obtain the flatness information of the wafer; and

releasing the wafer from being adsorbed by the dry adhesive fibrous structure in a part of the plurality of sections of the holding surface of the holding member based on the flatness information.

2. The flatness control method according to claim 1,

the step of obtaining the flatness information measures the flatness of the wafer held by the holding member to obtain the flatness information.

3. The flatness control method according to claim 1,

the step of obtaining the flatness information measures the flatness of the wafer held by the holding member to obtain the flatness information.

4. The flatness control method according to any one of claims 1 to 3,

the dry-adhesive fibrous structure comprises a plurality of microfibers and/or a plurality of nanofibers.

5. The flatness control method according to any one of claims 1 to 3,

the wafer comprises a plurality of divided areas;

the flatness information of the wafer includes flatness information of each of the plurality of divided regions of the wafer;

the flatness control method further comprises the following steps:

a step of determining a controlled region protruding toward the holding surface of the holding member among the plurality of divided regions of the wafer from the flatness information;

the step of releasing the suction releases the suction of the dry adhesive fibrous structure to the wafer in a section corresponding to the controlled region among the plurality of sections of the holding member.

6. A method for forming a coating film on a wafer, comprising the steps of:

a step of controlling the flatness of the wafer by the flatness control method according to any one of claims 1 to 5; and

a step of applying a composition for forming a coating film on the wafer having the controlled flatness.

7. The method for forming a coating film according to claim 6, further comprising the steps of:

preparing a reference wafer, and causing the entire surface of the reference wafer facing the holding member to adhere to the holding surface of the holding member to hold the reference wafer on the holding member;

a step of measuring the flatness of the reference wafer held by the holding member to obtain information on the flatness of the reference wafer;

a step of applying the composition for forming a coating film to the reference wafer held by the holding member to form a reference coating film; and

acquiring information on the surface state of the reference coating film;

in the step of releasing the suction, the suction of the dry-adhesive fibrous structure to the wafer is released in a part of the plurality of segments of the holding surface of the holding member based on the information on the flatness of the wafer, the information on the flatness of the reference wafer, and the information on the surface state of the reference coating film.

8. The method for forming a coating film according to claim 6 or 7, wherein,

the coating film-forming composition is applied by spin coating.

9. The method for forming a coating film according to claim 6 or 7, wherein,

as the composition for forming a coating film, a composition for forming a photoresist film is used.

10. A flatness control apparatus for controlling flatness of a wafer, comprising:

a holding member having a holding surface including a plurality of segments each having a dry-adhesive fibrous structure, the holding member holding the wafer by sucking the wafer by the holding surface; and

and a controller configured to release the wafer from being adsorbed by the dry adhesive fibrous structure in a part of the plurality of segments of the holding surface of the holding member based on the flatness information of the wafer.

11. The flatness control apparatus of claim 10, further comprising:

the measuring device measures the flatness of the wafer to obtain the flatness information of the wafer.

12. The flatness control apparatus according to claim 10 or 11,

the dry-adhesive fibrous structure comprises a plurality of microfibers and/or a plurality of nanofibers.

13. The flatness control apparatus according to claim 10 or 11,

the wafer comprises a plurality of divided areas;

the flatness information of the wafer includes flatness information of each of the plurality of divided regions of the wafer;

the controller performs the following control:

determining a controlled region protruding toward the holding surface of the holding member among the plurality of divided regions of the wafer from the flatness information; and

in a section corresponding to the controlled region among the plurality of sections of the holding member, the suction of the wafer by the dry adhesive fibrous structure is released.

14. A coating film forming apparatus comprising:

the flatness control apparatus according to any one of claims 10 to 13; and

a coating device for coating the wafer which is held and planarized by the flatness control device with the composition for forming a coating film.

15. The coating film forming apparatus according to claim 14, wherein,

the controller releases the adsorption of the dry adhesive fibrous structure to the wafer in a part of the plurality of segments of the holding surface of the holding member based on information on flatness of the wafer, information on flatness of a reference wafer, and information on a surface state of a reference coating film;

the information on the flatness of the reference wafer is information on the flatness of the reference wafer in a state where the entire surface facing the holding member is attracted to the holding surface of the holding member;

the information on the surface state of the reference coating film is information on the surface state of the coating film formed on the reference wafer in a state where the entire surface facing the holding member is adsorbed to the holding surface of the holding member by using the coating apparatus.

Technical Field

The invention relates to a flatness control method, a method for forming a coating film, a flatness control device, and a coating film forming device.

Background

With the demand for miniaturization of a pattern specification accompanying high integration and high speed of a large scale integrated circuit (LSI), various techniques have been developed for performing finer and more precise patterning of a light source used in photolithography using a chemically amplified photoresist, which is currently used as a general-purpose technique.

In photolithography using a chemically amplified photoresist, a wafer as a workpiece is fixed, and a chemically amplified photoresist film forming material is applied in the fixed state. As a method for fixing a wafer, for example, a method widely spread by vacuum adsorption, electrostatic adsorption, or the like, or a method using an adhesive film, an adhesive sheet, or the like is known (for example, patent documents 1 and 2). However, when the wafer is fixed by using an adhesive film or an adhesive sheet, there is a problem that a part of the adhesive remains on the wafer when the wafer is removed from the support.

As a fixing method without using an adhesive or an adhesive, for example, a vacuum chuck described in patent document 3 and a method of clamping by capillary force described in patent document 4 are used. By using these methods, the problem of adhesive remaining can be solved.

Referring to fig. 14 and 15, an example of applying a chemically amplified photoresist to a wafer by the "wafer fixing method by vacuum suction using a vacuum chuck" will be described. First, as shown on the left side of fig. 14, a wafer 5 is placed on the vacuum chuck 4. Next, as shown in the center of fig. 14, the vacuum chuck 4 is operated to hold the wafer 5. Next, as shown in the right side of fig. 14, the wafer 5 is rotated while being held by the vacuum chuck 4, and a composition for forming the chemically amplified photoresist film 9 is spin-coated on the wafer 5, thereby forming the chemically amplified photoresist film 9. Fig. 15 is a plan view of the chemically amplified photoresist film 9 viewed from the direction C in fig. 14.

As shown in fig. 14 and 15, the chemically amplified photoresist film 9 thus formed inevitably has an uneven coating film. The reason is that the wafer 5 coated with the chemically amplified photoresist film 9 sometimes does not have sufficient flatness. If the film thickness is not uniform, a range in which the focus of a partial exposure apparatus is out of focus is generated during pattern processing by photolithography, and the size of the exposure pattern varies in this region.

Therefore, in order to perform fine and highly accurate patterning by photolithography, it is necessary to develop a technique for reducing the variation in the thickness of a coating film generated when a coating film such as a chemically amplified photoresist film is applied.

Further, not only in the case of forming a coating film, but also in the case of processing while holding a wafer, processing is unevenly performed on the wafer surface unless the wafer is held flat, and therefore, how to hold the wafer flat becomes a problem.

[ Prior art documents ]

[ patent document ]

[ patent document 1] specification of patent No. 5646395

[ patent document 2] Japanese patent application laid-open No. 2019-134109

[ patent document 3] Japanese patent application laid-open No. 2005-32959

[ patent document 4] patent No. 5596058

[ patent document 5] U.S. patent application publication No. 2015/0368519

[ patent document 6] U.S. Pat. No. 9,566,722

[ patent document 7] U.S. patent application publication No. 2015/0072110

[ non-patent document ]

[ non-patent document 1] APPLIED MATERIAL & INTERFACES, Vol.1, No.4, pp.849-855,2009

[ non-patent document 2] J.Adhesion Sci.Technol., Vol.17, No.8, pp.1055-1073

Disclosure of Invention

[ problems to be solved by the invention ]

The present invention has been made to solve the above problems, and an object of the present invention is to provide a flatness control method capable of sufficiently controlling the flatness of a wafer, and a flatness control apparatus capable of implementing the method. It is another object of the present invention to provide a method for forming a coating film that can reduce variation in the thickness of the coating film that occurs when the coating film is applied, and a coating film forming apparatus that can implement this method.

[ means for solving problems ]

In order to achieve the above object, the present invention provides a flatness control method for a wafer, comprising the steps of: preparing a holding member having a holding surface including a plurality of segments each having a dry-adhesive fibrous structure; a step of attaching a wafer to the holding surface of the holding member to hold the wafer on the holding member; measuring the flatness of the wafer to obtain the flatness information of the wafer; and releasing the wafer from being adsorbed by the dry adhesive fibrous structure in a part of the plurality of sections of the holding surface of the holding member based on the flatness information.

According to the flatness control method of the present invention, the suction of the dry adhesive fibrous structure to the wafer is partially released based on the information on the flatness of the wafer, and the flatness of the wafer can be sufficiently controlled. By using the "wafer whose flatness is controlled by the flatness control method of the present invention", for example, when a composition for forming a coating film is applied to the wafer, the occurrence of variations in the thickness of the coating film can be reduced.

The step of obtaining the flatness information may be a step of measuring the flatness of the wafer held by the holding member to obtain the flatness information.

Alternatively, the step of obtaining the information on the flatness may be a step of measuring the flatness of the wafer held by the holding member to obtain the information on the flatness.

Thus, the flatness information of the wafer for controlling the flatness may be either before or in a state of being held by the holding member.

In the dry-adhesive fibrous structure, it is preferable to use a structure containing a plurality of microfibers and/or a plurality of nanofibers.

By using the dry-adhesive fibrous structure including the microfibers and/or nanofibers, the portion of the wafer adsorbed by the dry-adhesive fibrous structure can be more easily released.

The wafer comprises a plurality of divided areas, and the flatness information of the wafer comprises flatness information of each of the plurality of divided areas of the wafer; the flatness control method of the present invention further comprises the steps of: a step of determining a controlled region protruding toward the holding surface of the holding member among the plurality of divided regions of the wafer from the flatness information; the step of releasing the suction preferably releases the suction of the wafer by the dry adhesive fibrous structure in a section corresponding to the controlled region among the plurality of sections of the holding member.

By releasing the suction of the dry adhesive fiber structure to the wafer in the section corresponding to the controlled region of the wafer among the sections of the holding surface of the holding member, the unevenness of the wafer can be reduced, and the flatness of the wafer can be more precisely controlled.

The present invention also provides a method for forming a coating film on a wafer, comprising the steps of: controlling the flatness of the wafer by the flatness control method of the invention; and a step of applying a composition for forming a coating film on the wafer having the controlled flatness.

By applying the composition for forming a coating film to a wafer whose flatness has been controlled by the flatness control method of the present invention, the occurrence of variations in the thickness of the coating film can be reduced when the composition for forming a coating film is applied.

The method for forming a coating film of the present invention further comprises the steps of:

preparing a reference wafer, and causing the entire surface of the reference wafer facing the holding member to adhere to the holding surface of the holding member to hold the reference wafer on the holding member;

a step of measuring the flatness of the reference wafer held by the holding member to obtain information on the flatness of the reference wafer;

a step of forming a reference coating film by applying a composition for forming a coating film on the reference wafer held by the holding member; and

acquiring information on the surface state of the reference coating film;

in the step of releasing the suction, it is preferable that the suction of the dry adhesive fiber structure to the wafer is released in a part of the plurality of segments of the holding surface of the holding member based on the information on the flatness of the wafer, the information on the flatness of the reference wafer, and the information on the surface state of the reference coating film.

In such a method of forming a coating film, the flatness of the wafer can be controlled more sufficiently in accordance with, for example, the coating conditions and the coating apparatus, and variation in the coating film thickness of the coating film formed on the wafer can be suppressed more, whereby a desired coating film can be formed with good reproducibility.

Further, the coating film-forming composition is preferably applied by spin coating.

By spin coating the composition for forming a coating film, the occurrence of coating film thickness variations can be further reduced.

Further, a composition for forming a photoresist film can be used as the composition for forming a coating film.

By using the composition for forming a photoresist film as the composition for forming a coating film, a uniform photoresist film free from coating film thickness variation can be formed.

Further, the present invention provides a flatness control apparatus for a wafer, comprising: a holding member having a holding surface including a plurality of segments each having a dry-adhesive fibrous structure, the holding member holding the wafer by sucking the wafer by the holding surface; and a controller configured to release the wafer from being adsorbed by the dry adhesive fibrous structure in a part of the plurality of segments of the holding surface of the holding member based on information on flatness of the wafer.

According to the flatness control device of the present invention, the suction of the dry adhesive fiber structure to the wafer can be partially released based on the information on the flatness of the wafer, and the flatness of the wafer can be sufficiently controlled. By using the "wafer whose flatness is controlled by using the flatness control apparatus of the present invention", for example, when the coating film forming composition is applied to the wafer, the occurrence of variation in the thickness of the coating film can be reduced.

The flatness control apparatus of the present invention may further include a measuring device for measuring the flatness of the wafer to obtain information on the flatness of the wafer.

With such a flatness control device, it is possible to obtain information on the flatness of the wafer held by the holding member and/or obtain information on the flatness of the wafer held by the holding member by the measuring device.

The dry-adhesive fibrous structure preferably comprises a plurality of microfibers and/or a plurality of nanofibers.

The flatness control device provided with the "dry-type adhesive fibrous structure including a plurality of microfibers and/or a plurality of nanofibers" can more easily release the portion of the dry-type adhesive fibrous structure wafer that has been adsorbed.

The wafer includes a plurality of divided regions, the flatness information of the wafer includes flatness information of each of the plurality of divided regions of the wafer, and the controller preferably performs the following control: determining a controlled region protruding toward the holding surface of the holding member among the plurality of divided regions of the wafer from the flatness information; and releasing the adsorption of the dry adhesive fiber structure to the wafer in a section corresponding to the controlled area among the plurality of sections of the holding member.

The flatness control device is provided with a controller which is configured to release the adsorption of the dry adhesive fiber structure to the wafer in a section corresponding to the controlled area of the wafer among a plurality of sections of the holding surface of the holding member, and can reduce the unevenness of the wafer, thereby more precisely controlling the flatness of the wafer.

The present invention also provides a coating film forming apparatus comprising the flatness control apparatus of the present invention and a coating apparatus for coating a composition for forming a coating film on the wafer flattened by holding the wafer by the flatness control apparatus.

According to the coating film forming apparatus including the flatness control apparatus of the present invention and the coating apparatus configured as described above, the occurrence of coating film thickness variation when the coating film forming composition is coated can be reduced.

The controller releases the adsorption of the dry adhesive fibrous structure to the wafer in a part of the plurality of segments of the holding surface of the holding member based on the information on the flatness of the wafer, the information on the flatness of the reference wafer and the information on the surface state of the reference coating film,

the information on the flatness of the reference wafer is preferably information on the flatness of the reference wafer in a state where "the entire surface facing the holding member is attracted to the holding surface of the holding member",

the information on the surface state of the reference coating film is preferably information on the surface state of the coating film formed on the reference wafer in a state where "the entire surface facing the holding member is adsorbed to the holding surface of the holding member" using the coating apparatus.

By using such a coating film forming apparatus, it is possible to control the flatness of the wafer more sufficiently in accordance with, for example, the coating conditions or the coating apparatus, and to form a desired coating film with good reproducibility by suppressing the variation in the coating film thickness of the coating film formed on the wafer.

[ Effect of the invention ]

As described above, according to the flatness control method of the present invention, the flatness of the wafer can be sufficiently controlled. By forming a coating film by applying the composition for forming a coating film on a wafer whose flatness is controlled in this manner, for example, the occurrence of variation in the thickness of the coating film when the composition is applied can be reduced. Further, by forming a coating film by the flatness control method of the present invention, a photoresist film with less variation in coating film thickness can be formed. By using a photoresist film with little variation in coating film thickness in photolithography, patterning with no variation in line width can be performed.

Further, according to the flatness control apparatus of the present invention, the flatness control method of the present invention can be implemented. Further, according to the method for forming a coating film of the present invention, by forming a coating film by applying the composition for forming a coating film on a wafer whose flatness has been controlled, the occurrence of variations in the thickness of the coating film when the composition is applied can be reduced. Further, according to the coating film forming apparatus of the present invention, the coating film forming method of the present invention can be carried out.

Drawings

FIG. 1 is a schematic cross-sectional view showing an example of a flatness control apparatus according to the present invention.

Fig. 2 is a schematic cross-sectional view showing a holding member provided in the flatness control apparatus of fig. 1.

Fig. 3 is a schematic top view of the holding means shown in fig. 1 and 2.

FIG. 4 is a schematic cross-sectional view showing another example of the flatness control apparatus according to the present invention.

Fig. 5 is a schematic cross-sectional view showing an example of a holding member that can be provided in the flatness control apparatus according to the present invention.

Fig. 6 is a schematic sectional view showing another example of a holding member which the flatness control apparatus of the present invention may be provided with.

FIG. 7 is a schematic sectional view showing an example of the coating film forming apparatus of the present invention.

Fig. 8 is a schematic cross-sectional view of an example of the holding member shown in fig. 2 in a state where adsorption of a part of the wafer is released.

Fig. 9 is a schematic sectional view showing one step in an example of the method for forming a coating film of the present invention.

Fig. 10 is a schematic sectional view of a wafer and a coating film after a coating step of a coating film forming composition in an example of a coating film forming method of the present invention.

Fig. 11 is a plan view of the coating film viewed from the direction a of fig. 10.

Fig. 12 is a schematic cross-sectional view of a reference wafer and a reference coating film formed thereon in a state of being held by suction to a holding member of a flatness control apparatus according to an example of the present invention.

Fig. 13 is a plan view of the reference coating film viewed from the direction B of fig. 12.

Fig. 14 is a schematic cross-sectional view showing a series of steps of a conventional coating film forming method.

Fig. 15 is a plan view of the photoresist film viewed from the direction C of fig. 14.

Wherein the symbols in the drawings are briefly described as follows:

1: a holding member; 2: a controller; 3: a measuring device; 4: a vacuum chuck; 5: a wafer; 5': a reference wafer; 6: a coating device; 7: a coating film (photoresist film); 8: a reference coating film; 9: a photoresist film; 10: a holding surface; 11: a segment; 11 a: a portion of a segment; 11 b: a portion of a segment; 12: a dry-adhesive fibrous structure; 12 a: fibers; 12 b: a spatula-shaped front end; 12 c: a front end; 12 d: fibers; 12 e: a spatula-shaped front end; 13: a base; 13 a: penetrating through the hole; 14: a carrier; 14 a: penetrating through the hole; 51: a segmented region; 51 a: a controlled area; 51 b: a region outside the controlled region; 100: a flatness control device; 200: a coating film forming device; A. b, C: and (4) direction.

Detailed Description

As described above, in order to perform fine and highly accurate patterning by photolithography, it is necessary to develop a method capable of sufficiently controlling the flatness of a wafer.

The present inventors have made extensive studies to solve the above-mentioned problems, and as a result, have found that the flatness of a wafer can be sufficiently controlled by using a dry adhesive fiber structure as a holding member and partially releasing the suction of the dry adhesive fiber structure to the wafer based on the flatness information of the wafer as an object to be controlled, thereby completing the present invention.

That is, the flatness control method of the present invention is a method for controlling the flatness of a wafer, which comprises the following steps: preparing a holding member having a holding surface including a plurality of segments each having a dry-adhesive fibrous structure; a step of attaching a wafer to the holding surface of the holding member to hold the wafer on the holding member; measuring the flatness of the wafer to obtain the flatness information of the wafer; and releasing the wafer from being adsorbed by the dry adhesive fibrous structure in a part of the plurality of sections of the holding surface of the holding member based on the flatness information.

The method for forming a coating film of the present invention is a method for forming a coating film on a wafer, including the steps of: controlling the flatness of the wafer by the flatness control method of the invention; and a step of applying a composition for forming a coating film on the wafer having the controlled flatness.

Further, a flatness control apparatus according to the present invention is a wafer flatness control apparatus, including: a holding member having a holding surface including a plurality of segments each having a dry-adhesive fibrous structure, the holding member holding the wafer by sucking the wafer by the holding surface; and a controller configured to release the wafer from being adsorbed by the dry adhesive fibrous structure in a part of the plurality of segments of the holding surface of the holding member based on information on flatness of the wafer.

The coating film forming apparatus of the present invention includes the flatness control apparatus of the present invention and a coating apparatus for coating a composition for forming a coating film on the wafer flattened by being held by the flatness control apparatus.

The present invention will be described in detail below, but the present invention is not limited thereto.

< flatness control device >

First, the flatness control apparatus of the present invention will be described.

The flatness control device of the present invention is a flatness control device for a wafer, including: a holding member having a holding surface including a plurality of segments each having a dry-adhesive fibrous structure, the holding member holding the wafer by sucking the wafer by the holding surface; and a controller configured to release the wafer from being adsorbed by the dry adhesive fibrous structure in a part of the plurality of segments of the holding surface of the holding member based on information on flatness of the wafer.

According to the flatness control device of the present invention, the suction of the dry adhesive fiber structure to the wafer can be partially released based on the information on the flatness of the wafer, so that the flatness of the wafer can be sufficiently controlled. By using the wafer whose flatness is controlled by the flatness control apparatus of the present invention, the occurrence of coating film thickness variation can be reduced when the coating film forming composition is coated on the wafer.

The control of the flatness of the wafer by the present invention is not limited to the improvement of the flatness of the wafer, and includes, for example, the adjustment of the flatness of the wafer so that a desired coating film thickness can be obtained with good reproducibility when the coating film is formed by applying the coating film forming composition to the wafer. That is, according to the present invention, the flatness of the wafer can be controlled as necessary to produce desired irregularities on the wafer.

Next, an embodiment of the flatness control apparatus according to the present invention will be described in detail with reference to the drawings.

FIG. 1 is a schematic cross-sectional view showing an example of a flatness control apparatus according to the present invention. Fig. 2 is a schematic cross-sectional view of a holding member provided in the flatness control apparatus of fig. 1. Fig. 3 is a schematic top view of the holding means shown in fig. 1 and 2.

The flatness control apparatus 100 shown in fig. 1 includes a holding means 1 and a controller 2. The holding member 1 has an upwardly facing holding face 10.

As shown in fig. 2 and 3, the holding surface 10 of the holding member 1 comprises a plurality of segments 11. In fig. 3, the segments 11 are distinguished by lines, but may not have a clear boundary. Each segment 11 is provided with a dry-adhesive fibrous structure 12 shown in fig. 2. The dry-adhesive fibrous structure 12 is supported by a base 13. The base 13 is supported by a carrier 14. The holding member 1 is composed of a dry adhesive fiber structure 12, a base 13 and a carrier 14. The details of the dry-adhesive fibrous structure 12, the base 13, and the carrier 14 will be described later.

The dry-adhesive fibrous structure 12 can be adsorbed to an object in contact with the tip thereof, and can release adsorption (desorption) of the object. The tips of the dry-adhesive fibrous structures 12 constitute a holding surface 10. The holding member 1 includes the dry adhesive fibrous structure 12, and can hold the wafer 5 by sucking the wafer 5 to the holding surface 10. Further, by including the dry-adhesive fibrous structure 12 in each of the plurality of segments 11 of the holding surface 10 of the holding member 1, the wafer 5 can be sucked and released by the dry-adhesive fibrous structure 12 in each segment 11 independently of the other segments 11.

The controller 2 releases the suction of the wafer 5 by the dry adhesive fibrous structure 12 in a part of the plurality of segments 11 of the holding surface 10 of the holding member 1 based on the information on the flatness of the wafer 5. The connection form between the controller 2 and the holding member 1 is not particularly limited.

The flatness control apparatus 100 shown in fig. 1 includes the holding member 1 and the controller 2 as described above, and can partially release the suction of the dry adhesive fibrous structure to the wafer based on the information on the flatness of the wafer, thereby sufficiently controlling the flatness of the wafer.

For example, the controller 2 may release the suction of the dry adhesive fiber structures 12 to the wafer 5 in a part of the plurality of segments 11 of the holding surface 10 of the holding member 1 based on the information on the flatness of the wafer 5, the information on the flatness of the reference wafer, and the information on the surface state of the reference coating film.

The information on the flatness of the reference wafer used here is the information on the flatness of the reference wafer in the state where "the entire surface facing the holding member 1 is attracted to the holding surface 10 of the holding member 1". The information on the surface state of the reference coating film is information on the surface state of the reference coating film formed on the reference wafer in the "state where the entire surface facing the holding member 1 is attracted to the holding surface 10 of the holding member 1". Details of the reference wafer and the reference coating film will be described later.

The controller 2 configured as described above can use the surface state of the reference coating film as information of the fingerprint. The controller 2 can release the suction of the dry adhesive fiber structure 12 to the wafer 5 in a part of the plurality of segments 11 of the holding surface 10 of the holding member 1 based on the information on the flatness of the wafer 5, the information on the flatness of the reference wafer, and the information on the surface state of the reference coating film, thereby controlling the flatness of the wafer 5 so that the coating film having a desired surface state can be formed on the wafer 5. The desired surface state referred to herein is, for example, a surface state after "a point (for example, coating distribution) to be corrected with reference to the surface state of the coating film" is corrected.

The flatness control apparatus 100 having such a controller 2 can control the flatness of the wafer 5 more sufficiently according to, for example, the coating conditions or the coating apparatus. Thus, by using the flatness control apparatus 100, it is possible to further suppress the variation in the coating film thickness of the coating film formed on the wafer 5, and to form a desired coating film with good reproducibility.

The flatness control apparatus 100 of the present invention further includes a measuring apparatus 3 shown in fig. 4, which measures the flatness of the wafer 5 to acquire information on the flatness of the wafer 5.

The measuring device 3 can acquire information on the flatness of the wafer 5 before being held by the holding member 1, or can acquire information on the flatness of the wafer 5 in a state of being held by the holding member 1. The method of obtaining the flatness information of the wafer 5 measured by the measuring apparatus 3 is not particularly limited. For example, the measurement device 3 may obtain information on the flatness of the wafer 5 by an optical interferometric flatness tester.

The flatness control apparatus of the present invention may not include a measuring apparatus. In this case, the flatness information of the wafer may be acquired by using a measuring device different from the flatness control device of the present invention.

As shown in fig. 2, the wafer 5 may include a plurality of divided regions 51. In this case, the flatness information of the wafer 5 may include flatness information of each of the plurality of divided regions 51. As shown in fig. 2, each of the divided regions 51 may not have a clear boundary. In fig. 2, the wafer 5 is shown as a large wave for explanation, but the flatness of the wafer 5 as the object to be controlled is not particularly limited.

In this case, the controller 2 preferably performs the following control: determining a controlled area 51a protruding toward the holding surface 10 of the holding member 1 among the plurality of divided areas 51 of the wafer 5 from the flatness information of the wafer 5; and releasing the suction of the wafer 5 by the dry adhesive fibrous structure 12 in the segment 11a corresponding to the controlled region 51a among the plurality of segments 11 of the holding member 1. By providing such a controller 2, the unevenness of the wafer can be reduced, and the flatness of the wafer can be controlled more precisely.

Next, an example of the holding member provided in the flatness control apparatus according to the present invention will be described in detail with reference to the drawings. However, the holding member provided in the flatness control apparatus according to the present invention is not limited to the example described below, as long as it has a holding surface including a plurality of segments, each of the plurality of segments has a dry-adhesive fibrous structure, and the wafer is held by being adsorbed by the holding surface.

Fig. 5 is a schematic cross-sectional view of a holding member as an example of a flatness control apparatus according to the present invention. Fig. 5 is a schematic cross-sectional view of a part of the holding member 1 shown in fig. 2.

The holding means 1 comprises: a carrier 14, a base 13 supported by the carrier 14, and a dry adhesive fiber structure (12) supported by the base 13.

The dry-adhesive fibrous structure 12 includes a plurality of fibers 12 a. The plurality of fibers 12a may comprise a plurality of nanofibers, may comprise a plurality of microfibers, or may comprise both. That is, the dry-bondable fibrous structure 12 may include a plurality of microfibers and/or a plurality of nanofibers.

Each of the plurality of fibers 12a shown in fig. 5 has a spatula-shaped (spatula-shaped) tip 12 b. The plurality of front ends 12b constitute the holding face 10. The plurality of tips 12b can be dry-bonded (dry adhesion) to the object by applying a surface force such as van der waals force between the tips and the object in contact therewith. This bonding is also associated with capillary action.

The fibers 12a included in the dry-adhesive fibrous structure 12 can be variously deformed. For example, as shown in fig. 6, a plurality of fibers 12d may be further provided at the tip 12c of each fiber 12 a. The diameter of the fibers 12d is smaller than the diameter of the fibers 12a supporting them. The plurality of fibers 12d each include a spatula-shaped tip 12 e. The plurality of front ends 12e constitute the holding face 10. The structure shown in fig. 6 may be a hierarchical structure, for example.

The adsorbability of the dry-adhesive fibrous structure 12 can be controlled by, for example, the diameter of the fibers 12a, the shape of the ends 12b, the diameter of the fibers 12d, and/or the shape of the ends 12 e.

The base 13 supports the plurality of fibers 12a integrally therewith. The base 13 is formed with through holes 13a at positions corresponding to each of the plurality of fibers 12 a. In other aspects, the base 13 may be separate from the plurality of fibers 12 a.

The carrier 14 supports the base 13. The carrier 14 is provided with through holes 14a communicating with the through holes 13a of the base 13.

For example, the adsorption and release of the fibers 12a to the wafer 5 may be controlled for each fiber 12a by stressing the fibers 12a through the through holes 13a of the base 13 and the through holes 14a of the carrier 14, and/or reducing or eliminating the stress imposed on the fibers 12 a.

That is, the flatness control device of the present invention includes the dry-adhesive fibrous structure including the microfibers and/or nanofibers, and thereby can more easily release the portion of the dry-adhesive fibrous structure that is adsorbed to the wafer.

The dry-adhesive fibrous structure 12 exemplified above is disclosed in, for example, patent document 5 and non-patent document 1. The methods for producing the dry-adhesive fibrous structure 12 described above include, for example, the methods described in patent documents 6 and 7 and non-patent document 2. Further, these documents do not mention "control of suction by a dry adhesive fiber structure in order to control flatness of a wafer".

The flatness control method that can be performed using the flatness control apparatus of the present invention will be described later.

< coating film Forming apparatus >

Next, a coating film forming apparatus of the present invention will be described.

The coating film forming apparatus of the present invention includes the flatness control apparatus of the present invention and a coating apparatus that coats the wafer held and planarized by the flatness control apparatus with the composition for coating film formation.

The flatness control apparatus of the present invention described above can sufficiently control the flatness of a wafer. According to the coating film forming apparatus of the present invention including such a flatness control apparatus and the above-described coating apparatus, the occurrence of coating film thickness variations can be reduced when the coating film forming composition is applied to a wafer.

Next, an embodiment of the coating film forming apparatus of the present invention will be described in detail with reference to the drawings.

FIG. 7 is a schematic sectional view showing an example of the coating film forming apparatus of the present invention.

The coating film forming apparatus 200 shown in fig. 7 includes a flatness control apparatus 100 and a coating apparatus 6. The flatness control apparatus 100 is the flatness control apparatus 100 according to the embodiment of the present invention shown in fig. 1.

The coating film forming apparatus 200 shown in fig. 7 further includes a vacuum chuck 4. The vacuum chuck 4 detachably supports the holding member 1.

The holding member 1 can hold the wafer 5 on the holding face 10. The flatness control apparatus 100 can control the flatness of the wafer 5 as previously described.

The coating device 6 coats the wafer 5 with the composition for forming a coating film.

When the controller 2 releases the suction of the dry adhesive fiber structures 12 to the wafer 5 in a part of the plurality of segments 11 of the holding surface 10 of the holding member 1 based on the information on the flatness of the wafer 5, the information on the reference wafer flatness, and the information on the surface state of the reference coating film, in addition to the information on the flatness of the wafer 5 described above, the controller 2 preferably controls the suction in accordance with the specification and the coating condition of the coating device 6, for example.

The method of forming a coating film using the coating film forming apparatus of the present invention will be described later.

< flatness control method >

Next, a flatness control method according to the present invention will be described.

The flatness control method of the invention is a flatness control method of a wafer, comprising the following steps: preparing a holding member having a holding surface including a plurality of segments each having a dry-adhesive fibrous structure; a step of attaching a wafer to the holding surface of the holding member to hold the wafer on the holding member; measuring the flatness of the wafer to obtain the flatness information of the wafer; and releasing the wafer from being adsorbed by the dry adhesive fibrous structure in a part of the plurality of sections of the holding surface of the holding member based on the flatness information.

According to the flatness control method of the present invention, the suction of the dry adhesive fibrous structure to the wafer can be partially released based on the information on the flatness of the wafer, and the flatness of the wafer can be sufficiently controlled. By using the wafer whose flatness is controlled by the flatness control method of the present invention, the occurrence of coating film thickness variations can be reduced when the coating film forming composition is applied to the wafer.

The flatness control method of the present invention can be implemented using the previously described flatness control apparatus of the present invention, for example. However, the flatness control method of the present invention may be performed by using a device other than the flatness control device of the present invention.

Next, an embodiment of the flatness control method according to the present invention will be described in detail with reference to the drawings.

The flatness control method described below uses the flatness control apparatus 100 described with reference to fig. 1 to 3. Therefore, redundant description will be omitted.

First, the step of preparing the holding member 1 shown in fig. 1 to 3 is performed.

Next, as shown in fig. 2, the wafer 5 is attracted to the holding surface 10 of the holding member 1, and the wafer 5 is held by the holding member 1. At this time, the wafer 5 is sucked to the plurality of blocks 11 shown in fig. 3. Can be adsorbed on all the sections 11, or can be adsorbed on a part of the sections 11.

On the other hand, the flatness of the wafer 5 is measured, and information on the flatness of the wafer 5 is acquired.

The step of acquiring the flatness information may be, for example, measuring the flatness of the wafer 5 held by the holding member 1 to acquire the flatness information. In this case, the measuring apparatus 3 described with reference to fig. 4 may be used, or a measuring apparatus different from the flatness control apparatus 100 may be used.

Alternatively, the step of acquiring the flatness information may be performed by measuring the flatness of the wafer 5 held by the holding member 1 to acquire the flatness information. In this case, the measuring device 3 described with reference to fig. 4 may be used, or a measuring device different from the flatness control device 100 may be used.

That is, the step of acquiring the information of the flatness may be performed before the step of holding the wafer 5 on the holding member 1, or may be performed after the step of holding the wafer 5 on the holding member 1.

The flatness information of the wafer 5 preferably includes information of each of the plurality of divided areas 51 of the wafer 5.

Next, a step of releasing the suction of the wafer 5 by the dry-adhesive fibrous structure 12 in a part of the plurality of segments 11 of the holding surface 10 of the holding member 1 based on the information of the flatness of the wafer 5 is performed.

By this step, the flatness of the wafer 5 can be sufficiently controlled. On the other hand, when the suction of the dry adhesive fiber structure 12 to the wafer 5 is released in all the sections of the wafer 5 among the plurality of sections 11, the flatness of the wafer 5 cannot be controlled.

A specific example of the procedure for releasing the adsorption will be described with reference to FIG. 8.

Fig. 8 is a schematic cross-sectional view showing an example of a state in which a part of the wafer is released from the suction by the holding member shown in fig. 2. In fig. 8, the outline of the wafer 5 before the "partial release" of the suction is performed is indicated by a dotted line, and the outline of the wafer after the "partial release" of the suction is indicated by a solid line.

In this case, the following steps are also included: and determining a controlled region 51a protruding toward the holding surface 10 of the holding member 1 among the plurality of divided regions 51 of the wafer 5 from the flatness information of the wafer 5.

As shown in fig. 8, in the suction releasing step, suction of the wafer 5 by the dry adhesive fibrous structure 12 is released in the segment 11a corresponding to the controlled region 51a among the plurality of segments 11 of the holding member 1.

As shown in fig. 8, in such a desorption step, a difference in adsorption state occurs between the zone 11b in which adsorption is not desorbed and the zone 11a in which adsorption is desorbed among the plurality of zones 11. Due to this difference, the controlled area 51a of the wafer 5 is displaced upward, and the area 51b other than the controlled area 51a is displaced downward. As a result, the unevenness of the wafer 5 can be further reduced, and the flatness of the wafer 5 can be more precisely controlled.

Further, by releasing the suction of the portion, the suction state of the wafer 5 and the holding member 1 can be controlled.

The steps of determining the controlled area 51a and the step of releasing the adsorption described above can be executed by using the controller 2 shown in fig. 1.

As shown in fig. 3, by using the holding member 1 having the "holding surface 10 including the plurality of segments 11 arranged in a grid like a checkerboard", the flatness of the wafer 5 can be more finely controlled.

As described above, by using the dry-adhesive fibrous structure including the microfibers and/or nanofibers, the portion of the wafer to be adsorbed by the dry-adhesive fibrous structure can be more easily released.

Specific means for controlling the adsorption and the release thereof are not particularly limited. For example, as previously described with reference to fig. 5, the adsorption and release of the fibers 12a and the wafer 5 may be controlled for each fiber 12a by stressing the fibers 12a or reducing or eliminating the stress imposed on the fibers 12a through the through holes 13a of the base 13 and the through holes 14a of the carrier 14. Alternatively, a weaker force may be applied to the controlled area 51a of the wafer 5 to release the adsorption of the fibers 12a of the segment 11 a.

< method for Forming coating film >

Next, a method for forming a coating film of the present invention will be described.

The method for forming a coating film of the present invention comprises the steps of: controlling the flatness of the wafer by the flatness control method of the invention; and a step of applying a composition for forming a coating film on the wafer having the controlled flatness.

By applying the composition for forming a coating film to a wafer whose flatness has been controlled by the flatness control method of the present invention, the occurrence of coating film thickness variations can be reduced when the composition for forming a coating film is applied.

The method for forming a coating film of the present invention further comprises the steps of:

preparing a reference wafer, and causing the entire surface of the reference wafer facing the holding member to adhere to the holding surface of the holding member to hold the reference wafer on the holding member;

a step of measuring the flatness of the reference wafer held by the holding member to obtain information on the flatness of the reference wafer;

a step of applying a composition for forming a coating film onto the reference wafer held by the holding member to form a reference coating film; and

acquiring information on the surface state of the reference coating film;

in the step of releasing the suction, it is preferable that the suction of the dry adhesive fiber structure to the wafer is released in a part of the plurality of segments of the holding surface of the holding member based on the information on the flatness of the wafer, the information on the flatness of the reference wafer, and the information on the surface state of the reference coating film.

By such a method of forming a coating film, for example, the flatness of the wafer can be controlled more sufficiently in accordance with the coating conditions and the coating apparatus, and variation in the coating film thickness of the coating film formed on the wafer can be suppressed more, whereby a desired coating film can be formed with good reproducibility.

Further, the coating film-forming composition is preferably applied by spin coating.

By spin coating the coating film-forming composition, a flatter coating film can be formed, and as a result, the occurrence of coating film thickness variations can be further reduced.

The composition for forming a coating film can be a composition for forming a photoresist film, which is particularly required to have flatness.

By using the composition for forming a photoresist film as the composition for forming a coating film, a flat and uniform photoresist film can be formed. In particular, according to the method for forming a coating film of the present invention, a photoresist film in which the occurrence of coating film thickness variation is reduced can be formed.

The formed photoresist film can be used as a coating film for lithography in, for example, a single-layer or multilayer photoresist etching method. Therefore, examples of the composition for forming a photoresist film include: a composition for forming an upper photoresist film, a composition for forming a lower photoresist film, a composition for forming a silicon-containing photoresist film, and a composition for forming an organic lower film, such as a photosensitive photoresist composition, an electron beam photosensitive photoresist composition, a directional self-assembly photoresist composition, and a photoresist composition for nanoimprinting. The coating film forming composition used in the coating film forming method of the present invention is not limited to a photoresist film forming composition.

The method for forming a coating film of the present invention can be carried out, for example, using the apparatus for forming a coating film of the present invention described above. However, the method for forming a coating film of the present invention may be performed by a device other than the apparatus for forming a coating film of the present invention.

Next, an embodiment of the method for forming a coating film of the present invention will be described with reference to the drawings.

The coating film forming apparatus 200 of the example described with reference to fig. 7 is used in the coating film forming method of the example described below. Therefore, redundant description will be omitted.

First, a step of controlling the flatness of the wafer 5 by the flatness control method of the present invention using the flatness control apparatus 100 is performed.

Next, as shown in fig. 9, the holding member 1 is fixed using the vacuum chuck 4 below the carrier 14 of the holding member 1. This ensures stability of the wafer 5 during coating.

Next, a step of applying the composition for forming a coating film to the wafer 5 whose flatness has been controlled by using the coating apparatus 6 is performed.

Fig. 10 is a schematic sectional view showing a state where the coating film 7 is formed by applying the composition for forming a coating film to the wafer 5. Fig. 11 is a plan view of the coating film viewed from the direction a of fig. 10.

When fig. 11 is compared with fig. 15 described above, it is found that the coating film 7 formed by the coating film forming method of the present invention has less unevenness than the chemically amplified photoresist film 9 formed by the conventional method. The reason is that the flatness of the wafer 5 is sufficiently controlled by the flatness control method of the present invention.

Further, since the coating film 7 shown in fig. 10 and 11 has less unevenness than the chemically amplified photoresist film 9 formed by the conventional method, the variation in coating film thickness is reduced.

When the coating film 7 is a photoresist film, the photoresist film 7 thus formed suppresses the occurrence of coating film thickness variations which are detrimental to photolithography, and is therefore suitable for fine patterning by photolithography without variations in line width.

As described above, the dry-adhesive fibrous structure 12 can be adsorbed not only to an object in contact with the tip thereof but also to release the adsorption (desorption) of the object. Therefore, after the coating film 7 is formed, the suction of the dry adhesive fibrous structure 12 to the wafer 5 can be released in all the segments 11 of the holding surface 10 of the holding member 1, and thereby the wafer 5 can be easily removed from the holding member 1.

Next, another modification of the method for forming a coating film of the present invention will be described with reference to the drawings.

The method of forming a coating film of this example is substantially different from the previously described examples in the following points: also comprises the following steps: acquiring information of flatness of the reference wafer and information of surface state of the reference coating film; in the step of releasing the suction, the suction of the dry adhesive fibrous structure to the wafer is partially released based on the information on the flatness of the wafer to which the coating film is applied, the information on the flatness of the reference wafer, and the information on the surface state of the reference coating film.

In this example, first, a reference wafer 5' shown in fig. 13 is prepared. The reference wafer 5' is not particularly limited, but is preferably made of the same material as the wafer 5 on which the coating film is formed. Next, as shown in fig. 12, the entire surface of the reference wafer 5 'facing the holding member 1 is attracted to the holding surface 10 of the holding member 1, and the reference wafer 5' is held by the holding member 1. The flatness of the reference wafer 5 'in this state is measured, and information on the flatness of the reference wafer 5' is obtained. This measurement can be performed by the same means as the "means for acquiring the flatness information of the wafer 5" described previously.

Next, the coating film forming composition is applied to the reference wafer 5' in this state by using the coating apparatus 6 in the same procedure as described with reference to fig. 9 and 10. Thereby, a reference coating film 8 shown in fig. 12 is formed on the reference wafer 5'.

As is clear from the "plan view shown in fig. 13 viewed from the direction B of fig. 12", the formed reference coating film 8 includes unevenness on the surface. This unevenness is called haze, for example, and is a disadvantage of the pattern processing by photolithography.

Next, information on the surface state of the formed reference coating film 8 is acquired. The information on the surface state of the coating film 8 can be obtained by, for example, an optical interferometric film thickness meter or an ellipsometric film thickness meter.

Subsequently, the reference wafer 5' is removed from the holding member 1. Next, a wafer 5 on which a coating film is formed is prepared. Then, the entire surface of the wafer 5 facing the holding member 1 is attracted to the holding surface 10 of the holding member 1, and the wafer 5 is held by the holding member 1.

Next, in this example, the controller 2 releases the adsorption of the dry-adhesive fibrous structure 12 in a part of the plurality of segments 11 of the holding surface 10 of the holding member 1, based on the information on the flatness of the wafer 5, the information on the flatness of the reference wafer 5' obtained previously, and the information on the surface state of the reference coating film 8. The release of the adsorption can be controlled in accordance with the specification and coating conditions of the coating device 6.

Next, the coating film forming composition is applied to the wafer 5 whose flatness has been controlled as described above by using the coating apparatus 6 in the same procedure as described with reference to fig. 9 and 10. Thus, "the coating film 7 with reduced coating film thickness variation similar to that described with reference to fig. 11" can be formed on the wafer 5.

According to the method of forming a coating film of this example, the flatness of the wafer 5 can be controlled more sufficiently in accordance with the coating conditions and the coating apparatus, and variation in the coating film thickness of the coating film 7 formed on the wafer 5 can be suppressed more, whereby a desired coating film 7 can be formed with good reproducibility. In this case, the flatness of the wafer 5 is not necessarily controlled to be high in order to reduce the fluctuation of the coating film.

In particular, according to the method for forming a coating film of this example, the coating film 7 in which the defect generated in the reference coating film 8 is corrected can be formed.

[ examples ]

The present invention will be specifically described below with reference to examples and comparative examples, but the present invention is not limited thereto.

(example 1)

In example 1, the flatness of the wafer was controlled by the following procedure.

First, the same flatness control device 100 as shown in fig. 1 to 3 is prepared. The holding surface 10 comprises one thousand segments 11 arranged in a checkerboard grid as shown in fig. 3. The dry-adhesive fibrous structure 12 of the holding member 1 has a shape schematically shown in fig. 5.

Next, a wafer 5 as a control target is prepared. Wafer 5 comprises one thousand silicon wafers of singulated areas 51.

As shown in fig. 2, the wafer 5 is attracted to the holding surface 10 of the holding member 1, and the wafer 5 is held by the holding member 1.

In this state, the flatness of each of the divided regions 51 of the wafer 5 is measured, and flatness information is acquired. The flatness of the wafer 5 is 0.4 μm.

Next, the controller 2 determines, based on the obtained flatness information, a controlled region 51a protruding toward the holding surface 10 of the holding member 1 among the plurality of divided regions 51 of the wafer 5.

Next, as shown in fig. 8, the controller 2 releases the suction of the dry adhesive fibrous structure 12 to the wafer 5 in the segment 11a corresponding to the controlled region 51a among the plurality of segments 11 of the holding member 1. The release of the adsorption is achieved by drawing the fibers 12 in the section 11a through the through-holes 13a and 14a shown in fig. 5. The flatness of the wafer 5 thus controlled over-flatness was 0.02 μm.

(example 2)

In example 2, the flatness of the wafer was controlled by the same procedure as in example 1 except for the following points.

In example 2, before being held by the holding member 1, the flatness of the wafer 5 was measured to obtain flatness information, and the flatness was controlled in the same manner as in example 1 based on the flatness information. The flatness of the wafer 5 held in front of the holding member 1 was 0.01 μm. In example 2, the same wafer 5 as in example 1 was used.

The flatness of the wafer 5 whose over-flatness was controlled in example 2 was 0.01 μm.

(example 3)

In example 3, a photoresist film was formed on the wafer 5 whose flatness was controlled in example 1 by the following procedure.

As shown in fig. 7, the wafer 5 whose flatness is controlled is held by the holding member 1 and fixed by the vacuum chuck 4.

Next, the test coating film forming composition is applied to the wafer 5 in this state by using the coating apparatus 6. A photoresist was used as a composition for forming a test coating film.

Then, the resist film is baked at 100 ℃.

(example 4)

In example 4, a photoresist film was formed on the wafer 5 whose flatness was controlled in example 2 by the same procedure as in example 3.

Comparative example 1

In comparative example 1, a photoresist film was formed on the wafer 5 on which flatness control was not performed by the same procedure as in example 3.

The same wafer 5 as that used in comparative example 1 and "wafer 5 before flatness control" used in examples 1 and 2 was used.

Comparative example 2

In comparative example 2, the wafer 5 was adsorbed to the holding member 1 and the wafer 5 was held by the holding member 1 in the same procedure as in example 1. Then, the wafer 5 is removed by releasing the suction of the wafer 5 by the holding member 1. The flatness of the removed wafer 5 was 0.6 μm. On the wafer 5 thus obtained, a photoresist film was formed in the same procedure as in example 3.

[ evaluation of coating film thickness fluctuation ]

The coating film thickness variation of the photoresist films obtained in examples 3 and 4 and comparative examples 1 and 2 was evaluated by the following procedure. One thousand points in the wafer plane are measured using an ellipsometer, and the maximum and minimum values of the measured values are determined. The results are shown in table 1 below.

[ Table 1]

	Coating film thickness fluctuation (difference between maximum value and minimum value)
		Example 3	0.3A
Example 4	0.3A
		Comparative example 1	0.5A
Comparative example 2	0.5A

As shown in table 1, it is understood that in examples 3 and 4 using wafers whose flatness was controlled by the flatness control method of the present invention (examples 1 and 2), the occurrence of coating film thickness variation can be reduced when the composition for forming a photoresist film is coated.

On the other hand, in comparative examples 1 and 2 using wafers that have not been controlled for flatness, it was not possible to suppress the occurrence of coating film thickness variations when forming a photoresist film.

(example 5)

In example 5, a photoresist film was formed on the wafer 5 whose flatness was controlled by the following procedure in the same manner as in example 3.

First, a reference wafer similar to the wafer 5 used in example 1 was prepared. Then, the reference wafer is attracted to the holding member 1, and the reference wafer is held by the holding member 1. In this state, the flatness of the reference wafer is measured, and information on the flatness of the reference wafer is acquired. The flatness of the reference wafer was 0.01 μm.

Next, a photoresist film, which is a reference coating film, was formed on the reference wafer by the same procedure as in example 3. The surface condition of the formed reference coating film was measured by the same procedure as described above, and information on the surface condition of the reference coating film was obtained.

Next, a wafer 5 identical to the wafer 5 used in example 1 was prepared. Then, the wafer 5 is attracted to the holding member 1, and the wafer 5 is held by the holding member 1. In this state, the flatness of the wafer 5 is measured, and information on the flatness of the wafer 5 is acquired. The flatness of the wafer was 0.01 μm.

Then, the controlled region of the plurality of divided regions 51 of the wafer 5 is determined based on the information of the flatness of the reference wafer, the information of the surface state of the reference coating film, and the information of the flatness of the wafer 5, which are obtained in the above manner. Next, the controller 2 releases the suction of the dry adhesive fibrous structure 12 to the wafer 5 in the section corresponding to the controlled region among the plurality of sections 11 of the holding member 1. The release of the adsorption is performed by drawing the fibers 12 through the through holes 13a and 14a shown in fig. 5 in a section corresponding to the controlled area among the plurality of sections 11 of the holding member 1. This controls the flatness of the wafer 5.

On the wafer 5 controlled in the above manner, a photoresist film was formed in the same procedure as in example 3. The formed photoresist film was evaluated for coating film thickness variation by the same procedure as in example 3.

The results are shown in table 2 below.

[ Table 2]

	Coating film thickness fluctuation (difference between maximum value and minimum value)
		Example 5	0.1A

As is clear from comparison of the results of example 3 shown in table 1 and the results of example 5 shown in table 2, in example 5 in which control was performed based on the information on the flatness of the reference wafer and the information on the surface state of the reference coating film in addition to the information on the flatness of the wafer 5, the occurrence of coating film thickness variation was reduced more than in example 3.

In the above, the flatness control method and the flatness control apparatus according to the present invention are applied to form a coating film, particularly a photoresist film, but the processing by applying the flatness control method and the flatness control apparatus according to the present invention is not limited to the formation of a coating film. For example, the flatness control method and the flatness control apparatus of the present invention can be suitably applied to processing requiring flatness of a wafer. The coating film formed by applying the flatness control method and the flatness control apparatus of the present invention is not limited to a photoresist film.

The above description is only for the preferred embodiment of the present invention, and it is not intended to limit the scope of the present invention, and any person skilled in the art can make further modifications and variations without departing from the spirit and scope of the present invention, therefore, the scope of the present invention should be determined by the claims of the present application.