WO2008056614A1 - Reflow method, pattern-forming method, and method for manufacturing tft - Google Patents

Abstract

There is prepared an object to be processed which has a foundation layer film and a resist film pattern-formed above the foundation layer film in such a manner that there are an exposed region where the foundation layer film is exposed and a covered region where the foundation layer film is covered. Then, the object to be processed is subjected to a surface modification treatment so that the exposed region of the foundation layer film is surface-modified to suppress fluxion of the resist. After this surface modification treatment, resist of the resist film is softened and flowed to partially cover the exposed region, and then etching is performed by using the flowed resist as a mask, thereby forming a certain pattern.

Description

 Specification

 Reflow method, pattern forming method, and TFT manufacturing method

 Technical field

 The present invention relates to a resist reflow method that can be applied in the manufacturing process of, for example, a thin film transistor (TFT), a pattern forming method using the resist, and a TFT manufacturing method.

 Background art

 [0002] An active matrix liquid crystal display device holds a liquid crystal sandwiched between a TFT substrate on which a thin film transistor (TFT) is formed and a counter substrate on which a color filter is formed, and applies a voltage selectively to each pixel. It is configured to be able to. In the process of manufacturing the TFT substrate used here, a pattern of a photosensitive material such as a photoresist is repeatedly performed by a photolithography process, and thus a mask pattern is required for each photolithography process.

 [0003] However, in recent years, with the progress of high integration and miniaturization of liquid crystal display devices, the manufacturing process has become complicated, and the manufacturing cost tends to increase. Therefore, it has been studied to reduce the total number of processes by integrating the mask pattern formation process for photolithography, which should reduce the manufacturing cost. For example, using a halftone mask with a difference in light transmittance as an exposure mask and performing so-called half-exposure processing, a technique for patterning resist masks with different film thicknesses in a single exposure process is available. Proposed

(For example, JP-A-9-80740, JP-A-2005-108904).

[0004] An example of a manufacturing procedure of a TFT substrate using such a half exposure technique is as follows. For example, an insulating film, an amorphous silicon film, an ohmic contour outer film, and a metal film are stacked so as to cover the gate electrode formed on the glass substrate. Thereafter, a pattern is formed by a half exposure process so that the resist film corresponding to the channel region is thin, and metal film etching and silicon etching (etching of the ohmic contact film and amorphous silicon film) are performed.

[0005] After that, for example, ashing re-development processing is carried out to reduce the resist film thickness as a whole As a result, the thin film portion of the resist is removed, and the metal film corresponding to the channel region is exposed. Then, the exposed metal film is etched to form a source electrode and a drain electrode, and the ohmic contact film is further etched to expose the semiconductor film in the channel region to form a TFT element. Then, after removing the resist, an organic film made of a photosensitive material is deposited on the TFT element, and a pattern is formed by photolithography to form a contact hole. Furthermore, a conductive film such as indium tin oxide (ITO) is formed on the organic film, and the conductive film is etched using a resist patterned by a photolithography technique as a mask to form a transparent electrode. The TFT substrate is formed by the series of steps described above.

 [0006] In the above process, by using the half exposure technique, a silicon etching mask and an etching mask for forming the source electrode and the drain electrode can be formed in one photolithography process. . Therefore, the number of resist film formations can be reduced, and the amount of resist used can be reduced.

 [0007] By the way, in the manufacture of a TFT substrate using the above-described half-exposure process, it is possible to save resist and reduce the number of photolithography processes. An ashing process or a re-development process for removing the thin film portion by reducing the overall film thickness is required.

 [0008] When the thin film portion of the resist is removed by performing an ashing process, it is difficult to ensure the uniformity of the pattern accuracy within the substrate surface. In the case of redevelopment processing, since it is a liquid process that involves the application of a developer, the process flow becomes complicated due to the repetition of separate liquid processes of development and redevelopment processing, resulting in increased equipment costs and running costs. Lead to In addition, in order to ensure the accuracy of the redevelopment process, a pre-process for removing the altered surface layer of the resist in advance is necessary, and there is a limit to the reduction in the number of processes.

 Disclosure of the invention

 An object of the present invention is to provide a reflow method, a mask pattern forming method, and a mask pattern which can reduce the number of processes and the total process time while ensuring the accuracy of the mask pattern on the workpiece. It is to provide a manufacturing method of TFT.

[0010] According to the first aspect of the present invention, the lower layer film is exposed to a lower layer film and an upper layer than the lower layer film. Preparing an object to be processed having a resist film patterned so as to form an exposed region and a covering region coated with the lower layer film, and the lower layer film with respect to the object to be processed The exposed region of the substrate is subjected to surface modification treatment so that resist flow is suppressed, and after the surface modification treatment, the resist of the resist film is softened and flowed to partially cover the exposed region. And a reflow method is provided.

 [0011] According to a second aspect of the present invention, a resist film is formed in an upper layer than an etching target film of an object to be processed, the resist film is exposed, and the exposed resist film is formed. Forming a resist pattern by developing, performing a surface modification process on the exposed region of the film to be etched where the resist is not formed, so as to suppress resist flow, and the surface modification After the treatment, the resist of the resist film is softened and reflowed, and a reflow process for covering the target region of the film to be etched with the deformed resist is performed, and the deformed resist is used as a mask. The first etching is performed on the exposed region of the etching film, the resist after the deformation is removed, and the resist after the deformation is removed. It said re-exposed by being includes performing the second etching with respect to the target region of the Etsu quenching film, a pattern forming method is provided.

[0012] According to a third aspect of the present invention, a gate electrode is formed on a substrate, a gate insulating film covering the gate electrode is formed, and on the gate insulating film, a — Deposit Si film, Si film for ohmic contact and source / drain metal film, form a resist film on the source / drain metal film, and apply the resist film to a predetermined exposure mask. The resist film subjected to the exposure treatment is developed to form a pattern to form a resist mask for the source electrode and a resist mask for the drain electrode, and the resist mask for the source electrode and the Etching the source / drain metal film using the drain electrode resist mask as a mask to form a source electrode and a drain electrode; The exposed region of the Si film for ohmic contact that is not covered with the source electrode and the drain electrode is surface-modified so that the resist flow is suppressed, and the resist mask for the source electrode and By allowing an organic solvent to act on the resist mask for the drain electrode, softening the resist, and reflowing, Applying a reflow process for covering at least the Si film for ohmic contact in the recess for the channel region between the source electrode and the drain electrode with a resist deformed by reflow; and the resist and the source after deformation Etching the lower layer of the ohmic contact Si film and the a-Si film using the electrode and the drain electrode as a mask, removing the resist after the deformation, and removing the source electrode and the drain electrode The ohmic contact Si film is exposed again in the recess for the channel region between and the channel electrode recess exposed between the source electrode and the drain electrode as a mask. Etching a Si film for ohmic contact, and a method for manufacturing a TFT, including: .

[0013] According to a fourth aspect of the present invention, there is provided a storage medium that operates on a computer and stores a program for controlling a reflow processing system, the program comprising: a lower layer film; and the lower layer film Preparing an object to be processed having a resist film patterned to form an exposed region where the lower layer film is exposed on the upper layer and a covered region covered with the lower layer film; A surface modification process is performed on the exposed body of the lower layer film so that resist flow is suppressed, and after the surface modification process, the resist film resist is softened and flowed. Thus, a storage medium is provided for controlling the reflow processing system such that a reflow method including: partially covering the exposed area is performed.

 [0014] According to the fifth aspect of the present invention, a surface modification processing unit for performing a surface modification treatment on an object to be treated, and a resist on the object to be treated after the surface modification treatment in a solvent atmosphere. A pattern is formed so as to form a reflow processing unit that is softened and fluidized, a lower layer film, an exposed region in which the lower layer film is exposed above the lower layer film, and a covered region that is covered with the lower layer film. The object to be processed having the formed resist film is subjected to a surface modification process in the exposed region of the lower layer film so that the resist flow is suppressed, and after the surface modification process, There is provided a reflow processing system comprising: a control unit that controls to partially cover the exposed region by softening and flowing the resist.

[0015] According to the present invention, prior to the reflow process, the exposed surface of the lower layer film is subjected to a surface modification process in advance so that the flow of the softened resist is suppressed. Can effectively suppress the spread of the gap. This makes it possible to adjust the area of the base film that is fluidized by the reflow process and is covered with the deformed resist.

 Therefore, by applying the reflow method of the present invention to the manufacture of a semiconductor device such as a TFT element in which an etching process using a resist as a mask is repeatedly performed, high etching accuracy can be ensured, and the high performance of the semiconductor device can be ensured. It is possible to cope with integration and miniaturization. In addition, it is possible to reduce the number of resists and reduce the number of photolithography processes without requiring half exposure processing or re-development processing.

Brief Description of Drawings

 FIG. 1 is a schematic diagram showing a reflow processing system in which a reflow method of the present invention is implemented.

 2 is a cross-sectional view showing a schematic configuration of an adhesion unit (AD) mounted on the reflow system of FIG.

 FIG. 3 is a sectional view showing a schematic configuration of a reflow processing unit (REFLW) mounted on the reflow processing system of FIG.

4A] Cross-sectional process chart for explaining the comparative reflow method.

4B] Cross-sectional process chart for explaining the comparative reflow method.

4C] Cross-sectional process chart for explaining the comparative reflow method.

5A] Cross-sectional process chart for explaining the reflow method of the present invention.

 FIG. 5B is a process cross-sectional view for explaining the reflow method of the present invention.

 FIG. 5C is a process cross-sectional view for explaining a process of the reflow method of the present invention.

5D] Cross-sectional process chart for explaining the process of the reflow method of the present invention.

Sono 6] A graph showing the relationship between CD variation and reflow time.

 FIG. 7A is a cross-sectional view illustrating the principle of resist flow to a channel region in reflow processing.

 FIG. 7B is a cross-sectional view for explaining the principle of resist flow to the channel region in the reflow process.

 FIG. 8 is a flowchart showing an example of a manufacturing method of a TFT element for a liquid crystal display device to which the reflow method of the present invention is applied.

9A] A process cross-sectional view for explaining a manufacturing method of the TFT element of FIG. 9B is a process cross-sectional view for explaining the manufacturing method of the TFT element of FIG. 8.

 FIG. 9C is a process cross-sectional view for explaining the manufacturing method of the TFT element of FIG.

 9D is a process cross-sectional view for explaining the manufacturing method of the TFT element of FIG. 8.

 FIG. 9E is a process cross-sectional view for explaining the manufacturing method of the TFT element of FIG.

 FIG. 9F is a process cross-sectional view for explaining the manufacturing method of the TFT element of FIG.

 FIG. 9G is a process cross-sectional view for explaining the manufacturing method of the TFT element of FIG.

 FIG. 9H is a process cross-sectional view for explaining the manufacturing method of the TFT element of FIG.

 FIG. 91 is a process cross-sectional view for explaining the manufacturing method of the TFT element of FIG. 8.

 9J is a process cross-sectional view for explaining the manufacturing method of the TFT element of FIG. 8.

 FIG. 9K is a process cross-sectional view for explaining the manufacturing method of the TFT element of FIG.

 FIG. 9L is a process cross-sectional view for explaining the manufacturing method of the TFT element of FIG.

 BEST MODE FOR CARRYING OUT THE INVENTION

Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings.

 FIG. 1 is a schematic plan view showing an entire reflow processing system that can be suitably used in the reflow method of the present invention. Here, the resist film formed on the surface of the glass substrate for LCD (hereinafter simply referred to as “substrate”) G is softened and deformed after development, and reused as an etching mask when etching the underlying film A reflow processing system that includes a reflow processing unit that performs a reflow process for performing the reflow process and an adhesion unit that performs a surface modification process prior to the reflow process will be described as an example. The reflow processing system 100 is configured so that the substrate G can be transferred to and from an external resist coating and developing processing system, exposure device, etching device, ashing device, etc. via a substrate transfer line (not shown). Has been.

[0018] The reflow processing system 100 includes a cassette station (loading / unloading unit) 1 on which a cassette C that accommodates a plurality of substrates G is placed, and a substrate G with a reflow process and a surface modification process performed prior to the reflow process. A processing station (processing unit) 2 including a plurality of processing units for performing a series of processing including the above, and a control unit 3 that controls each component of the reflow processing system 100 are provided. In FIG. 1, the longitudinal direction of the reflow processing system 100 is the X direction, and the direction orthogonal to the X direction on the horizontal plane is the Y direction. The cassette station 1 is disposed adjacent to one end of the processing station 2. This cassette station 1 is provided with a transfer device 11 for loading and unloading the substrate G between the cassette C and the processing station 2, and the cassette station 1 is loaded into and out of the cassette C from the outside. Is done. In addition, the transport device 11 has a transport arm 11a that can move on a transport path 10 provided along the Y direction that is the arrangement direction of the cassettes C. The transfer arm 11a is provided so as to be able to advance and retract and rotate in the X direction, and is configured to transfer the substrate G between the cassette C and the processing station 2.

 The processing station 2 includes a plurality of processing units for performing a resist reflow process on the substrate G and a surface modification process as a pre-process. In each of these processing units, one substrate G is processed. The processing station 2 basically has a central transport path 20 for transporting a substrate G extending in the X direction. Each processing unit is placed on both sides of the central transport path 20 with the central transport path 20 interposed therebetween. It is arranged to face 20th.

 In addition, the central transport path 20 is provided with a transport device 21 for loading and unloading the substrate G to and from each processing unit, and is movable in the X direction, which is the arrangement direction of the processing units. It has a transport arm 21a. Furthermore, the transfer arm 21a is provided so as to be advanced and retracted in the Y direction, reciprocated in the vertical direction, and rotated, and is configured so that the substrate G can be transferred into and out of each processing unit. Yes.

 [0022] Arranged in this order from the cassette station 1 side to the adjunct unit (AD) 30 and the reflow processing unit (REFLW) 60 forces S along the central transfer path 20 of the processing station 2 On the other side along the central conveying path 20, three heating / cooling processing units HHP / COU 80a, 80b, 80c force S— 歹 IJ are applied. Each heating / cooling processing unit (HP / COL) 80a, 80b, 80c is stacked in multiple layers in the vertical direction (not shown).

[0023] Adhesion unit (AD) 30 is a representative of silylating agents such as HMDS (hexamethyldisilazane) and TMSDEA (N-trimethylsilyljetylamine) for substrate G prior to reflow treatment. An atmosphere containing the surface modification treatment agent is formed, and surface modification treatment is performed to promote the flow of the resist. These surface modification treatment agents are hydrophobized It has a treatment effect and is also known as a hydrophobizing agent!

 Here, the adhesion unit (AD) 30 will be described with reference to FIG.

 The adhesion unit (AD) 30 has a rectangular parallelepiped frame (not shown), and has a fixed chamber main body 31 and a lid 33 that can be raised and lowered inside the frame. The chamber body 31 is configured as a flat, rectangular parallelepiped lower container having an upper surface that is slightly larger in size than the substrate G.

 [0025] The lid 33 is configured as an upper container of a flat rectangular parallelepiped opening on the lower surface of substantially the same size (area) as the chamber body 31, and an HMDS supply source for storing HMDS used for surface modification as described later Connected to 35. The lid 33 is fixed to a plurality of horizontal support members 37 extending in the horizontal direction (X direction and Y direction), and each horizontal support member 37 is provided with an elevating drive mechanism (not shown) such as a plurality of air. It is connected to the piston rod of the cylinder. Therefore, when the piston rods of these air cylinders are advanced vertically upward, the lid 33 moves (rises) integrally with the horizontal support member 37, and the chamber is opened. When the piston rod is retracted vertically downward, the lid 33 moves (lowers) together with the horizontal support member 37 vertically (!).

 In the chamber body 31, a rectangular heating plate 41 having a size substantially corresponding to the substrate G is horizontally disposed and fixed by a fixture 42. The heating plate 41 is made of a metal having a high thermal conductivity, such as aluminum, and a heater (not shown) made of, for example, a resistance heating element is provided on the inside or the lower surface thereof.

 [0027] Further, the heating plate 41 is formed with a plurality of through holes 43, and each through hole 43 is provided with a lifter pin 44, and a substrate lifting mechanism 45 that lifts and lowers the substrate G up and down. Is provided. These lifter pins 44 project from the surface of the heating plate 41 between the transfer arm 21a (see FIG. 1) of the external transfer device 21 so that the substrate G can be delivered. The lifter pins 44 are connected to each other by a horizontal support plate 46 disposed under the heating plate 41, and are configured to be able to move up and down synchronously. It should be noted that a lifting drive unit force (not shown) for moving the horizontal support plate 46 up and down is disposed inside or outside the chamber body 31.

[0028] A seamless seal member 3 extending in the circumferential direction is formed on the upper end surface of the side wall of the chamber body 31. 2 is installed. The sealing member 32 is interposed between the lower end surface of the side wall of the lid 33 and the upper end surface of the side wall of the chamber body 31 in a state in which the lid 33 is combined with the chamber body 31 so that the lid 33 can be closed tightly. . Thereby, an airtight processing chamber 47 is formed by the chamber body 31 and the lid 33.

 An HMDS gas introduction port 48 is provided on one side surface of the lid 33, and an exhaust port 49 is provided on the other side surface facing the HMDS gas introduction port 48.

 The HMDS gas introduction port 48 includes a plurality of through holes 50 formed at an arbitrary interval on one side surface of the lid 33, a terminal adapter 53 of the gas supply pipe 51 attached to each through hole 50 from the outside, and each And a buffer chamber 54 provided inside the through hole 50 and having a large number of gas discharge ports 55 formed at regular intervals.

 The exhaust port 49 has a large number of air holes 56 formed at regular intervals on the side surface of the lid 33 facing the HMDS gas introduction port 48, and is provided outside the side wall of the lid 33. It has an exhaust duct chamber 57. An exhaust port 58 formed at the bottom of the exhaust duct chamber 57 is connected to an exhaust pump (not shown) through an exhaust pipe 59.

 When performing the surface modification process in the adhesion unit (AD) 30 having such a configuration, first, the transport arm 21a of the transport device 21 is brought up with the lifter pins 44 of the substrate lift mechanism 45 raised. Receives board G from Then, after the lifter pin 44 is lowered and the substrate G is placed on the calo heat plate 41, the lid 33 is vertically lowered from the retracted position and brought into contact with the chamber body 31 to seal the chamber. The substrate G is heated by the heating plate 41 to a predetermined temperature, for example, 110 ° C. to 120 ° C. Then, the HMDS gas is supplied from the HMDS supply source 35 to the processing chamber 47 through the gas supply pipe 51 and the HMDS gas introduction port 48 while exhausting the inside of the processing chamber 47 by an exhaust pump (not shown). In the processing chamber 47, an HMDS gas force S ejected from the gas discharge port 55 of the HMDS gas introduction port 48 and an air flow toward the exhaust port 49 are formed, and the surface of the substrate G (processed surface) in the middle To modify the surface.

The HMDS gas that has passed through the processing chamber 47 is sent from the vent hole 56 to the exhaust duct chamber 57 at the exhaust port 49 and is exhausted therefrom by the action of the exhaust pump. After the prescribed treatment time has elapsed and the surface modification treatment is completed, supply of HMDS gas and exhaust pump Then, the lid 33 is pulled upward from the chamber main body 31 by the ascending drive of a lifting drive mechanism (not shown) and lifted up to a predetermined retracted position as it is. Thereafter, the lifter pin 44 of the substrate lifting mechanism 45 is raised, the substrate G is lifted above the heating plate 41, and transferred to the transfer arm 21 a of the transfer device 21. Thereafter, the substrate G after the surface modification treatment is unloaded from the adhesion unit (AD) 30 by the transfer arm 21a.

[0033] The substrate G after the surface modification treatment is then carried into the reflow treatment unit (REFLW) 60 of the treatment station 2 by the transfer arm 21a, and the resist formed on the substrate G is removed from the organic solvent such as a thinner atmosphere. A reflow process is performed to soften and change the mask shape.

 Here, the configuration of the reflow processing unit (REFLW) 60 will be described in more detail. FIG. 3 is a schematic sectional view of the reflow processing unit (REFLW) 60. The reflow processing unit (HREFLW) 60 has a chamber 61, and this chamber 61 is composed of a lower chamber 61a and an upper chamber 61b abutting on the upper portion of the lower chamber 61a. The The upper chamber 61b and the lower chamber 61a are configured to be opened and closed by an opening / closing mechanism (not shown), and the substrate G is loaded and unloaded by the transfer device 21 when the chamber is open.

In the chamber 61, a support table 62 that supports the substrate G horizontally is provided. The support table 62 is made of a material having excellent thermal conductivity such as aluminum!

[0036] The support table 62 is driven by a lift mechanism (not shown) and lifts and lowers the substrate G. Three lift pins 63 (only two are shown in FIG. 3) 1S Provided so as to penetrate the support table 62 It has been. When transferring the substrate G between the lifting pins 63 and the transfer device 21, the lift pins 63 lift the substrate G from the support table 62 and support the substrate G at a predetermined height position. During the reflow process, for example, the tip of the support table 62 is held at the same height as the upper surface.

[0037] Exhaust ports 64a and 64b are formed at the bottom of the lower chamber 61a, and an exhaust system 64 is connected to the exhaust ports 64a and 64b. Then, the atmospheric gas in the chamber 61 is exhausted through the exhaust system 64. [0038] A temperature control medium flow path 65 is provided inside the support table 62. In the temperature control medium flow path 65, for example, a temperature control medium such as temperature control cooling water is supplied to the temperature control medium introduction pipe 65a. And is discharged from the temperature control medium discharge pipe 65b and circulated, and its heat (for example, cold heat) is transferred to the substrate G through the support table 62, whereby the processing surface of the substrate G is changed. The desired temperature is controlled.

 [0039] The ceiling wall portion of the chamber 61 is provided so as to face the shower head 66 force support table 62. A large number of gas discharge holes 66b are provided on the lower surface 66a of the shower head 66.

 In addition, a gas introduction part 67 is provided at the upper center of the shower head 66, and the gas introduction part 67 communicates with a space 68 formed in the shower head 66. A pipe 69 is connected to the gas inlet 67. The pipe 69 is connected to a bubbler tank 70 that vaporizes and supplies an organic solvent such as thinner, and an open / close valve 71 is provided in the middle thereof. An N gas supply pipe 74 connected to an N gas supply source (not shown) is provided at the bottom of the bubbler tank 70 as a bubble generating means for vaporizing the thinner.

 twenty two

 The The N gas supply pipe 74 has a mass flow controller 72 and an opening / closing valve 73.

 2

 Is provided. The bubbler tank 70 is provided with a temperature adjusting mechanism (not shown) for adjusting the temperature of the thinner stored therein to a predetermined temperature. Then, N gas is supplied from an N gas supply source (not shown) while the flow rate is controlled by the mass flow controller 72.

twenty two

 By introducing it into the bottom of the blur tank 70, the thinner in the bubbler tank 70, the temperature of which has been adjusted to a predetermined temperature, can be vaporized and introduced into the chamber 61 via the pipe 69 and the gas inlet 67! /

[0041] Further, a plurality of purge gas introduction portions 75 are provided at the upper peripheral portion of the shower head 66, and each purge gas introduction portion 75 is filled with, for example, N gas as purge gas.

 2

 A purge gas supply pipe 76 for supplying the gas to the inside 61 is connected. The purge gas supply pipe 76 is connected to a purge gas supply source (not shown), and an opening / closing valve 77 is provided in the middle thereof.

In the reflow processing unit (REFLW) 60 having such a configuration, first, the upper channel 61b is released from the lower chamber 61a, and in this state, the transfer arm 21a of the transfer device 21 is opened. As a result, the substrate G having the resist that has already been patterned and subjected to the surface modification treatment is loaded and placed on the support table 62. Then, the upper chamber 61b and the lower chamber 61a are brought into contact with each other, and the chamber 61 is closed.

Next, open the open / close valve 71 of the pipe 69 and the open / close valve 73 of the N gas supply pipe 74.

 2

 The flow rate of N gas is controlled by the mass flow controller 72 to control the vaporization amount of thinner.

 2

 In the meantime, the vaporized thinner is introduced into the space 68 of the shower head 66 from the bubbler tank 70 via the pipe 69 and the gas introduction part 67 and discharged from the gas discharge hole 66b. As a result, the inside of the chamber 61 has a thinner atmosphere with a predetermined concentration.

[0044] Since a patterned resist is already provided on the substrate G placed on the support table 62 in the chamber 61, the resist is exposed to a thinner atmosphere. Penetrates the resist. As a result, the resist is softened and its fluidity is increased, and the resist is deformed and a predetermined region (target region) on the surface of the substrate G is covered with the deformed resist. At this time, by introducing the temperature adjustment medium into the temperature adjustment medium flow path 65 provided inside the support table 62, the heat is transferred to the substrate G via the support table 62, thereby The processing surface of the substrate G is controlled to a desired temperature, for example, 20 ° C. The gas containing thinner discharged from the head 66 toward the surface of the substrate G contacts the surface of the substrate G, then flows toward the exhaust ports 64a and 64b, and is exhausted from the chamber 61 to the exhaust system 64. The

 [0045] After the reflow processing in the reflow processing unit (REFLW) 60 is completed as described above, the open / close valve 77 on the purge gas supply pipe 76 is opened while continuing the exhaust, and the purge gas introduction unit 75 is connected. N gas as a purge gas is introduced into the chamber 61,

 2

 Replace the atmosphere in the chamber. Thereafter, the upper chamber 61b is opened from the lower chamber 61a, and the substrate G after the reflow process is carried out from the reflow process unit (REFLW) 60 by the transfer arm 21a in the reverse procedure.

[0046] Three heating and cooling processing units (HP / COU 80a, 80b, and 80c have a hot plate unit (HP) that heats the substrate G and a cooling plate that cools the substrate G, respectively. Unit (COL) force Multi-stage, for example, 2 stages are stacked in a total of 4 stages (not shown) .This heating / cooling processing unit (HP / COU 80a, 80b, 8 In Oc, the substrate G after the surface modification treatment and the reflow treatment is subjected to heat treatment or cooling treatment as necessary.

 As shown in FIG. 1, each component of the reflow processing system 100 is configured to be connected to and controlled by a controller 90 having a CPU of the controller 3. Connected to the controller 90 is a user interface 91 consisting of a keyboard on which an operator inputs commands to manage the reflow processing system 100, a display that visualizes and displays the operating status of the reflow processing system 100, and the like. Has been.

 [0048] In addition, the controller 90 stores a storage unit storing a recipe in which programs for executing various processes executed by the reflow processing system 100 under the control of the controller 90 and processing condition data are recorded. 92 is connected.

 [0049] Then, if necessary, the reflow processing system 100 is controlled under the control of the controller 90 by calling an arbitrary recipe from the storage unit 92 according to an instruction from the user interface 91 and causing the controller 90 to execute it. The desired processing at is performed. In addition, the recipe may be stored in a computer-readable storage medium such as a CD-ROM, a hard disk, a flexible disk, or a flash memory, or may be dedicated from another device, for example. It is also possible to use it by transmitting it through the line at any time.

In the reflow processing system 100 configured as described above, first, in the cassette station 1, the cassette in which the transfer arm 11 a of the transfer apparatus 11 contains the substrate G on which a resist pattern has already been formed. Access C and take out one board G. The substrate G is transferred from the transfer arm 11a of the transfer device 11 to the transfer arm 21a of the transfer device 21 in the central transfer path 20 of the processing station 2, and is transferred into the adhesion unit (AD) 30 by the transfer device 21. The Then, after the surface modification process is performed prior to the reflow process in the adhesion unit (AD) 30, the substrate G is taken out of the adhesion unit (AD) 30 by the transfer device 21, and is heated and cooled. (HP / COL) 80a, 8 Ob, or 80c. Then, the substrate G subjected to the cooling process in each heating / cooling processing unit (HP / COL) 80a, 80b, 80c is carried into the reflow processing unit (REF LW) 60, where the reflow process is performed. [0051] After the reflow process, the heating and cooling processing units (HP / COUs 80a, 80b, and 80c are subjected to predetermined heating and cooling processes as necessary. Substrate G after such a series of processes has been completed. Is taken out from the reflow processing unit (REFLW) 60 by the transfer device 21, delivered to the transfer device 11 of the cassette station 1, and stored in an arbitrary cassette C.

 Next, the principle of the reflow method of the present invention performed in the reflow processing unit (REFLW) 60 will be described in comparison with a comparative reflow method that does not perform surface modification processing. Here, a case where reflow processing is performed in the TFT manufacturing process will be described.

4A to 4C are process cross-sectional views for explaining a comparative reflow method. As shown in FIG. 4A, a gate electrode 202 and a gate line (not shown) are formed on an insulating substrate 201 made of a transparent substrate such as glass. Further, a gate insulating film 203 such as a silicon nitride film, a-Si (amorphous (Silicon) film 204, η + Si film 205 as an ohmic contact layer, source electrode 206a and drain electrode 206b, source electrode resist mask 210 and drain electrode resist mask 211 are laminated in this order. The source electrode 206a and the drain electrode 206b are etched using the source electrode resist mask 210 and the drain electrode resist mask 211 as a mask, and the surface of the n ⁺ Si film 205 as the base film is exposed.

Next, the object to be processed having such a laminated structure is subjected to a reflow process in a solvent atmosphere such as thinner in the reflow process unit (REFLW) 60 of the reflow process system 100. By this reflow treatment, the resist constituting the source electrode resist mask 210 and the drain electrode resist mask 211 is softened and has fluidity. By this reflow process, as shown in FIG. 4B, the surface of the n ⁺ Si film 205 in the recess 220 (channel formation region) between the source electrode 206a and the drain electrode 206b is covered with the fluidized deformation resist 212. This process is the purpose of preventing the n ⁺ Si layer 205 and the a- Si film 204 in the next step when etched ring, n ⁺ Si layer 205 and the a- Si film 204 of the channel formation region is etched Done in Thus, there is an advantage that the photolithography process can be omitted by reflowing the resist constituting the resist mask for source electrode 210 and the resist mask for drain electrode 211 and reusing the resist mask.

[0055] However, as shown in FIG. In some cases, the surface of the base n ⁺ Si film 205 may extend beyond the area of the electrode 206a and the drain electrode 206b. That is, the deformed resist 212 that serves as a mask when etching the n ⁺ Si film 205 and the a-Si film 204 in the next process protrudes beyond the area of the lower source electrode 206a and drain electrode 206b, and covers it. The area will spread. If the n + Si film 205 and the a-Si film 204 are etched in this state, there arises a problem that the etching accuracy is lowered. That is, as shown in FIG. 4C, the side surfaces of the n ⁺ Si film 205 and the a-Si film 204 after etching and the side surfaces of the source electrode 206a or the drain electrode 206b are not flush with each other, resulting in a step. In this way, when the TFT is manufactured by performing the following steps with the n ⁺ Si film 205 and the a-Si film 204 as a base protruding in the lateral direction with respect to the source electrode 206a or the drain electrode 206b, In addition, the aperture ratio, which represents the rate of light passing through, decreases, and photocurrent is generated by light striking the a-Si film 204 at this protruding part, increasing electrical noise and generating leakage current. There is concern that it will cause adverse effects.

 On the other hand, FIGS. 5A to 5D are process cross-sectional views for explaining the reflow method of the present invention. Figure

 The laminated structure shown in FIG. 5A is the same as that in FIG. As shown in FIG. 5B, the surface modification process is performed on the workpiece having such a laminated structure by the adhesion unit (AD) 30 of the reflow processing system 100. By the surface modification treatment, the exposed surface of the n + Si film 205 not covered with the source electrode 206a and the drain electrode 206b (the source electrode resist mask 210 and the drain electrode resist mask 211) is surface-modified. In this case, it is preferable to perform the surface modification treatment until the contact angle of pure water on the surface modification treatment surface 205a of the n + Si film 205 is 50 degrees or more, for example, 50 to 120 degrees. By modifying the surface so that the contact angle on the surface-modified surface 205a is 50 degrees or more, it is possible to effectively suppress the spread due to the resist flow in the subsequent reflow process.

Next, reflow treatment is performed in a reflow treatment unit (REFLW) 60 in a solvent atmosphere such as thinner. By this reflow treatment, the resist constituting the source electrode resist mask 210 and the drain electrode resist mask 211 is softened and has fluidity. By this reflow process, as shown in FIG. 5C, the surface of the n + Si film 205 in the recess 220 (channel formation region) between the source electrode 206a and the drain electrode 206b is fluidized. Covered with deformation resist 212. At this time, the fluidized resist is deformed, and the force that tries to spread over the surface of the underlying η + Si film 205 beyond the area of the source electrode 206 a and the drain electrode 206 b is already on the surface of the η + Si film 205. Since the modified surface 205a is formed by the modification, the flow of the softened resist is suppressed and the surface of the n ⁺ Si film 205 is difficult to spread.

Therefore, as shown in FIG. 5C, the deformed resist 212 after reflow is formed as a source electrode in the lower layer.

 Phenomenon force that protrudes beyond the area of 206a and drain electrode 206b is greatly suppressed compared to the comparative reflow method (see Fig. 4B). That is, the area covered with the deformed resist after reflowing is improved to be slightly larger than the areas of the source electrode 206a and the drain electrode 206b.

 [0059] For this reason, in the next step, the η + Si film 205 and the a-Si film 204 are etched using the deformed resist 212 as a mask, and after the deformed resist 212 is further removed, as shown in FIG. The side surfaces of the film 205 and the a-Si film 204 and the side surfaces of the source electrode 206a or the drain electrode 206b can be formed substantially flush with each other. Therefore, the problems in the comparative reflow method, such as a decrease in aperture ratio due to the formation of the a-Si film 204 extending laterally from the source / drain wiring, an increase in electrical noise due to the generation of photocurrent, and the occurrence of leakage current, are addressed. Solve with power S.

 [0060] It has also been confirmed from experimental results that the etching accuracy is improved by the surface modification treatment. Fig. 6 is a graph showing the test results of examining the effect of surface modification treatment on CD (Critical Dimension). The vertical axis of the graph represents the amount of change (ΔCD) between the resist pattern CD and the etched pattern CD, and the horizontal axis represents the time of the reflow process. The surface modification treatment was performed using HMDS at a treatment temperature of 110 ° C for 120 seconds.

 From Fig. 6, it can be seen that when the surface modification treatment using HMDS is performed, the resist pattern with a small CD change amount is accurately transferred to the etched shape compared to the case where the surface modification treatment is not performed. . This is thought to be the result of the resist modification suppressing the spread of the resist during reflow.

In the method of the present invention, after reflowing, a light ashing process is performed on the deformed resist 212 to further reduce the area covered by the deformed resist 212, and the source electrode It becomes possible to make it closer to the area of 206a and the drain electrode 206b. In this case, the ashing process uses, for example, a parallel plate type plasma processing apparatus, and an acid such as O.

 2 This light ashing process, which can be carried out under the conditions of a chamber gas pressure of about 13 Pa and a processing time of about 100 seconds, is performed by the plasma of the gas containing elemental gas. This part of the deformed resist 212 protrudes from the source electrode 206a and the drain electrode 206b. Therefore, the effect on the etching accuracy is almost a problem in a short time, for example, about two-thirds of the time required for etching, which is usually performed for the purpose of removing the resist thin film with half exposure technology. It will not be.

[0062] After the reflow process, when the η + Si film 205 and the a-Si film 204 are etched using the deformed resist 212 as a mask, the η + Si film 205 and the a-Si film 204 are isotropically etched. By performing the etching under such conditions as to proceed, it is possible to further suppress the phenomenon that the n ⁺ Si film 205 and the a-Si film 204 protrude laterally from the source electrode 206a and the drain electrode 206b after the etching. . For example, in the case of dry etching, a plasma processing apparatus such as a parallel plate method is used, and as an etching gas type, for example, SF, C1 gas, etc.

 This can be carried out using a gas mixture of 62 and under the conditions of a chamber internal pressure of 6.7 Pa and a processing time of 120 seconds.

 Next, the principle of resist flow to the channel region in the reflow process will be described.

 Fig. 7A is a diagram showing a modeled state of resist flow during reflow processing without surface modification treatment, and Fig. 7B shows resist flow during reflow processing with surface modification processing. It is a figure which models and shows a state. In these figures, the velocity of viscous flow during reflow and the velocity of flow due to surface tension are indicated by the size of the arrows.

[0064] The reflow speed is determined by the viscous flow of the softened resists 210a and 21 la and the surface tension of the resists 210a and 211a fused in the recess 220. As shown in FIG. 7A, when the surface modification treatment is not performed, the resists 210a and 211a softened quickly by the viscous flow and the flow due to the surface tension are formed in the recesses between the source electrode 206a and the drain electrode 206b. The resists 210a and 21la softened by the viscous flow spread to the outer regions of the flowing-in source electrode 206a and the drain electrode 206b. [0065] On the other hand, when the surface modification treatment is performed on the exposed portion of the n ⁺ Si film 205, the velocity of the viscous flow of the softened resist 210a, 21 la is suppressed, and the softened resist 210a, The spread of 211 a is suppressed.

[0066] In this case, the surface modification treatment is performed on the entire surface of the η + Si film 205 that is not covered by the source electrode 206a and the drain electrode 206b, so that the outside of the source electrode 206a and the drain electrode 206b. In addition to the region, the surface of the n ⁺ Si film 205 in the recess 220 exposed between the source electrode 206a and the drain electrode 206b is also surface-modified to form a surface-modified surface 205a. The speed of the viscous flow in that portion is also suppressed.

 [0067] As described above, the inflow speed of the resists 210a and 21 la into the recesses 220 is mutually changed into the recesses 220 formed only by the viscous flow of the resists 210a and 21 la softened by the reflow process. However, it is also affected by the flow promotion effect due to surface tension when resists 210a and 21 la that flowed in from the opposite direction come into contact.

 Accordingly, even when the surface modification treatment is performed, the resist 210a, 211a smoothly flows in due to the surface tension after the resist 210a, 211a comes into contact with the directional force into the recess 220. Then, as shown in FIG. 7B, the directional force and flow to the surface modification surface 205a outside the recess 220 (outside the source electrode 206a and the drain electrode 206b) are suppressed, while the resist in the recess 220 is suppressed. The inflow of 210a and 211a proceeds rapidly due to surface tension. With such a mechanism, even after the surface modification treatment, the flow rates of the resists 210a and 21la inside and outside the recess can be made to have a difference.

 [0069] As described above, by suppressing the resist flow by the surface modification treatment, it is possible to prevent the resist from spreading further while reliably covering the channel region. Therefore, it is possible to secure sufficient etching accuracy and to prevent generation of photocurrent in LCD products.

 Next, an embodiment in which the reflow method of the present invention is applied to a manufacturing process of a TFT element for a liquid crystal display device will be described with reference to FIG. 8 and FIGS. 9A to 9L.

FIG. 8 is a flowchart showing an example of a manufacturing method of a TFT element for a liquid crystal display device to which the reflow method of the present invention is applied, and FIGS. 9A to 9L are cross-sectional views for explaining the manufacturing method. First, as shown in FIG. 9A, a gate electrode 202 and a gate line (not shown) are formed on an insulating substrate 201 made of a transparent substrate such as glass, and a gate insulating film 203 such as a silicon nitride film, a-Si (amorphous (Silicon) film 204, η + Si film 205 as ohmic contact layer, and metal film 206 for electrodes such as A1 alloy and Mo alloy are stacked in this order (step)

51).

 Next, as shown in FIG. 9B, a resist 207 is formed on the electrode metal film 206 (step

 52). Then, as shown in FIG. 9C, using the exposure mask 300, the resist 207 is exposed (step S3). The exposure mask 300 is configured so that the resist 207 can be exposed in a predetermined pattern. By exposing the resist 207 in this manner, an exposed resist portion 208 and an unexposed resist portion 209 are formed as shown in FIG. 9D.

 [0072] After the exposure, by performing development processing, the exposed resist portion 208 is removed and the unexposed resist portion 209 can remain on the electrode metal film 206 as shown in FIG. 9E. Yes (step S4). The unexposed resist portion 209 is separated into a source electrode resist mask 210 and a drain electrode resist mask 211 and is patterned.

[0073] Then, using the source electrode resist mask 210 and the drain electrode resist mask 211 as an etching mask, the electrode metal film 206 is etched, and as shown in FIG. 9F, a recess 220 is formed in a portion that later becomes a channel region. Form (step S5). By this etching, the source electrode 206a and the drain electrode 206b are formed, and the surface of the n ⁺ Si film 205 can be exposed in the recess 220 between them.

 Next, in the adhesion unit (AD) 30 of FIG. 2, a surface modification process is performed on the exposed surface of the η + Si film 205 (step S6). The surface of the η + Si film 205 is modified by the surface modification treatment using a silylating agent, etc., and as shown in FIG. 9G, the surface modification treated surface 205a having a contact angle with pure water of 50 degrees or more. Is formed. That is, a state in which the resist hardly flows is formed on the surface modification surface 205a of the η + Si film 205.

Next, reflow processing is performed by the reflow processing unit (REFLW) 60 of FIG. 3 (step S 7). In this reflow process, a resist softened with an organic solvent such as a thinner is poured into a target recess 220 to be a channel region later. During this reflow process, the flow of the softened resist is suppressed on the surface modification surface 205a of the η + Si film 205. However, the inflow of the softening resist is accelerated by the action of the surface tension in the recess 220 which will later become the channel region, and the recess 220 can be reliably covered.

FIG. 9H shows a state where the recess 220 is covered with the deformation resist 212. When the surface modification treatment of step S6 is not performed, the deformed resist 212 extends to, for example, the periphery of the source electrode 206a and the drain electrode 206b (on the side opposite to the recess 220), for example, an _n ⁺ Si film 205 as an ohmic contact layer 205 As a result, the coated portion is not etched in the next silicon etching process, resulting in a problem that the etching accuracy is deteriorated and the TFT element is defective and the yield is lowered. In addition, if the area covered with the deformed resist 212 is designed to be estimated in advance, the area (dot area) required to manufacture one TFT element will increase, and the integration and miniaturization of TFT elements will increase. When it became difficult to respond to the problem, there was a problem!

On the other hand, in the present embodiment, the flow of the softened resist to the surface of the n ⁺ Si film 205 other than the recess 220 that becomes the channel region is suppressed by the surface modification treatment, and as shown in FIG. 9H. In addition, the area covered with the deformation resist 212 is substantially limited to the recess 220, which is the target area for the reflow process. Therefore, it is possible to ensure high etching accuracy and cope with high integration and miniaturization of TFTs.

 Next, a light ashing process is performed on the deformed resist after the reflow (step S8). By this ashing process, the area covered by the deformed resist 212 can be further reduced as shown in FIG. Therefore, the accuracy of the etching performed in the next step S9 can be significantly improved. Note that this ashing process is an optional process, and this ashing process may be omitted if there is little protrusion outside the deformed resist 212 after reflow (around the source electrode 206a and the drain electrode 206b). Touch with force S.

Next, as shown in FIG. 9J, the n + Si film 205 and the a-Si film 204 are etched using the source electrode 206a, the drain electrode 206b, and the deformed resist 212 as an etching mask (step S9). ). Thereafter, the deformed resist 212 is removed by a method such as a wet process using a resist stripping solution (step S10), and the source electrode 206a and the drain electrode 206b are exposed as shown in FIG. 9K. Next, using the source electrode 206a and the drain electrode 206b as an etching mask, the n ⁺ Si film 205 exposed in the recess 220 is etched (step Sl 1). As a result, a channel region 221 is formed as shown in FIG. 9L.

 Although the subsequent steps are not shown, for example, after forming an organic film so as to cover the channel region 221, the source electrode 206 a, and the drain electrode 206 b (step S 12), the source electrode 206 a ( A contact hole connected to the drain electrode 206b) is formed by etching (step S13), and then a transparent electrode is formed by indium tin oxide (ITO) or the like (step S14). The device is manufactured.

In the above embodiment, by performing the reflow process of Step S 7, the process of etching the electrode metal film 206 of Step S 5, and the n ⁺ Si film 205 and the a-Si film 204 of Step S 9 Can be performed by the resist formed by one photolithography process, that is, the resist mask 210 for the source electrode, the resist mask 211 for the drain electrode, and the deformation resist 212, so that the number of photolithography processes can be increased. Reduction and savings can be achieved. In addition, the surface modification process in step S6 ensures high etching accuracy, and can cope with high integration and miniaturization of TFT elements.

 Note that the present invention is not limited to the above-described embodiment, and various modifications can be made.

 For example, in the above description, the manufacture of TFT elements using a glass substrate for LCD was taken as an example, but reflow processing of resist formed on a substrate such as another flat panel display (FPD) substrate or a semiconductor substrate is performed. The present invention can also be applied when performing

Further, the reflow method of the present invention can be applied to a TFT manufacturing process in which half exposure technology and re-development processing are performed.

 Industrial applicability

The present invention can be suitably used in the manufacture of semiconductor devices such as TFT elements.

Claims

 The scope of the claims  [1] A processing target having a lower layer film, and a resist film patterned so as to form an exposed region in which the lower layer film is exposed above the lower layer film, and a covered region covered with the lower layer film Preparing the body,  Surface-modifying the object to be processed so that resist flow is suppressed in the exposed region of the lower layer film;  After the surface modification treatment, the resist of the resist film is softened and fluidized to partially cover the exposed region;  Including reflow method.  [2] The reflow method according to claim 1, wherein the surface modification treatment is performed in a chemical atmosphere containing a silylating agent.  [3] The reflow method according to claim 1, wherein the surface modification treatment is performed so that a contact angle with pure water of the exposed region subjected to the surface modification treatment is 50 degrees or more. [4] forming a resist film above the etching target film of the object to be processed;  Exposing the resist film; and  The exposed resist film is developed to form a resist pattern, and the resist of the film to be etched is formed to prevent the resist from flowing to the exposed area! Applying surface modification treatment to  After the surface modification treatment, the resist of the resist film is softened and reflowed, and a reflow treatment for covering the target region of the film to be etched with the deformed resist is performed.  Performing a first etching on the exposed region of the film to be etched using the deformed resist as a mask;  Removing the deformed resist;  Performing a second etching on the target region of the film to be etched that is re-exposed by removing the deformed resist; A pattern forming method. 5. The pattern forming method according to claim 4, further comprising reducing the covered area. 6. The pattern forming method according to claim 4, wherein the surface modification treatment is performed in a chemical solution atmosphere containing a silylating agent.  7. The pattern forming method according to claim 4, wherein the surface modification treatment is performed so that a contact angle with pure water of the exposed region subjected to the surface modification treatment is 50 degrees or more.  [8] In the object to be processed, a gate line and a gate electrode are formed on a substrate, and a gate insulating film is formed to cover them, and an a-Si film and an ohmic contact are sequentially formed on the gate insulating film from the bottom. 5. The pattern forming method according to claim 4, wherein the Si film for source and the metal film for source / drain are formed, and the etching target film includes at least the ohmic contour external Si film. [9] forming a gate electrode on the substrate;  Forming a gate insulating film covering the gate electrode;  Depositing an a-Si film, an ohmic contact Si film and a source 'drain metal film on the gate insulating film in order from the bottom;  Forming a resist film on the source / drain metal film;  Exposing the resist film using a predetermined exposure mask;  Developing and patterning the exposed resist film to form a resist mask for a source electrode and a resist mask for a drain electrode;  Etching the source / drain metal film using the source electrode resist mask and the drain electrode resist mask as a mask to form a source electrode and a drain electrode; Surface-treating the exposed region of the Si film for the contactor covered with the source electrode and the drain electrode so that the resist flow is suppressed; and An organic solvent is allowed to act on the electrode resist mask and the drain electrode resist mask to soften and reflow the resist, thereby at least the channel region in the channel region recess between the source electrode and the drain electrode. -Applying reflow treatment to cover Si film for Mic contact with resist deformed by reflow, Etching the lower Si film for ohmic contact and the a-Si film using the deformed resist and the source and drain electrodes as a mask, and removing the deformed resist, Re-exposing the silicon film for ohmic contact in the recess for the channel region between the source electrode and the drain electrode, and using the source electrode and the drain electrode as a mask, the channel between them. Etching the Si film for ohmic contact exposed in the concave portion for region, and a method for manufacturing a TFT. 10. The method for manufacturing a TFT according to claim 9, further comprising ashing the deformed resist to reduce a covering area after the reflow process. [11] The TFT manufacturing method according to [9], wherein when etching the Si film for ohmic contact and the a-Si film, dry etching is performed under a condition in which etching proceeds isotropically. .  12. The method for producing a TFT according to claim 9, wherein the surface modification treatment is performed in a chemical atmosphere containing a silylating agent.  13. The method for manufacturing a TFT according to claim 9, wherein the surface modification treatment is performed so that a contact angle with pure water of the exposed region subjected to the surface modification treatment is 50 degrees or more. [14] A storage medium that runs on a computer and stores a program for controlling the reflow processing system,  The program includes a lower layer film, a resist film patterned so as to form an exposed region where the lower layer film is exposed above the lower layer film, and a covered region covered with the lower layer film. Preparing an object to be processed,  Surface-modifying the object to be processed so that resist flow is suppressed in the exposed region of the lower layer film;  After the surface modification treatment, the resist of the resist film is softened and fluidized to partially cover the exposed region; A storage medium for controlling the reflow processing system such that a reflow method is performed. A surface modification processing unit for performing a surface modification treatment on the workpiece;  A reflow processing unit that softens and fluidizes the resist on the target object after the surface modification treatment in a solvent atmosphere;  An object to be processed having a lower layer film, and a resist film patterned to form an exposed region in which the lower layer film is exposed above the lower layer film and a covered region coated with the lower layer film Then, the exposed region of the lower layer film is subjected to a surface modification process so that resist flow is suppressed, and after the surface modification process, the resist of the resist film is softened and fluidized to flow the exposed region. A reflow processing system comprising: a control unit that controls to partially cover.