Plasma firing apparatus, plasma firing method, and method for forming conductive pattern

Abstract

To provide a plasma firing apparatus capable of reducing temperature unevenness in a flexible substrate when performing plasma-based reduction sintering processing on the flexible substrate.SOLUTION: A plasma firing apparatus 1 configured to perform plasma-based reduction sintering processing on a flexible substrate S on which a predetermined pattern is printed with ink containing a metal compound, includes: a vacuum chamber 10; a feed roller 20 for feeding the flexible substrate S; a take-up roller 30 for taking up the flexible substrate S; a cooling roller 40 for transporting the flexible substrate S from the feed roller 20 to the take-up roller 30 and cooling the flexible substrate S; and a plasma generator 50 configured to emit plasma to the flexible substrate S transported by the cooling roller 40 from an irradiation window 11 provided in the vacuum chamber 10. The irradiation window 11 extends along a width direction of the flexible substrate S with a dimension WW longer than a width dimension WS of the flexible substrate S.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to a plasma baking apparatus, a plasma baking method, and a method for forming a conductive pattern. [Background technology]

[0002] At present, a plasma sintering technique has been proposed and put to practical use, in which a pattern is drawn (printed) on a non-conductive substrate using a metal compound solution, and the drawn pattern is exposed to plasma for reduction sintering to form a conductive pattern. In recent years, a technique has been proposed in which a flexible substrate is used to perform continuous reduction sintering with plasma in order to increase the processing efficiency (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2011-100918 A Summary of the Invention [Problem to be solved by the invention]

[0004] When performing reduction-sintering treatment with plasma on a flexible substrate, if a film with low heat resistance (such as PET) is used as the flexible substrate, the reduction-sintering treatment must be performed under conditions that do not exceed the heat resistance temperature of the film. On the other hand, the reaction rate of plasma baking increases as the temperature during the reduction-sintering treatment increases. Therefore, in order to increase the treatment efficiency while suppressing damage to the film, it is necessary to make the reduction-sintering treatment temperature as high as possible without exceeding the heat resistance temperature of the film.

[0005] However, when the conventional technology described in Patent Document 1 is adopted, temperature unevenness occurs in the flexible substrate during film baking, and the temperature during reduction sintering treatment may locally exceed the heat resistance temperature of the film. To prevent such a situation from occurring, it is necessary to use a large-scale film cooling device or reduce the film conveying speed, but doing so poses the problem of increasing the size of the device and reducing processing efficiency.

[0006] The present invention has been made in consideration of the above circumstances, and aims to improve processing efficiency while suppressing damage to a flexible substrate by reducing temperature unevenness in a plasma sintering apparatus that performs reduction sintering processing on a flexible substrate using plasma. [Means for solving the problem]

[0007] In order to achieve the above-mentioned object, the plasma firing apparatus of the present invention is configured to perform a reduction sintering process using plasma on a flexible substrate on which a predetermined pattern has been printed using an ink containing a metal compound, and includes a vacuum chamber, a payout roller for paying out the flexible substrate in the vacuum chamber, a take-up roller for taking up the flexible substrate in the vacuum chamber, a cooling roller for transporting the flexible substrate from the payout roller to the take-up roller and cooling the flexible substrate, and a plasma generating device configured to irradiate plasma from an irradiation window provided in the vacuum chamber to the flexible substrate transported by the cooling roller, and the irradiation window extends along the width direction of the flexible substrate with a dimension longer than the width dimension of the flexible substrate.

[0008] With this configuration, the irradiation window provided in the vacuum chamber extends along the width direction of the flexible substrate with a dimension longer than the width of the flexible substrate, so that when the flexible substrate is subjected to reduction sintering treatment with plasma, the plasma can be irradiated uniformly over the entire width direction of the flexible substrate. This reduces temperature unevenness in the width direction of the flexible substrate, thereby making it possible to increase the treatment efficiency while suppressing damage to the flexible substrate.

[0009] In the plasma baking apparatus according to the present invention, a plasma generating device configured to irradiate plasma over the entire width of the flexible substrate by introducing microwaves along the width of the flexible substrate can be used.

[0010] By adopting such a configuration, microwaves can be introduced along the width direction of the flexible substrate, thereby irradiating plasma across the entire width direction of the flexible substrate, thereby further reducing temperature unevenness in the width direction of the flexible substrate.

[0011] In the plasma baking apparatus according to the present invention, the irradiation window can extend along the width direction of the flexible substrate with a dimension that is 1.5 to 4.5 times the width of the flexible substrate.

[0012] By adopting such a configuration, the irradiation window extends along the substrate width direction with a specific dimension (a dimension between 1.5 and 4.5 times the width dimension of the flexible substrate), so that the temperature unevenness in the width direction of the flexible substrate can be further reduced. Note that it is preferable to extend the irradiation window along the substrate width direction with a dimension between 3 and 4 times the width dimension of the flexible substrate, since this prevents the device from becoming unnecessarily large.

[0013] In the plasma baking apparatus according to the present invention, the diameter of the cooling roller can be set to be 3 to 12 times the dimension of the emission window in the substrate transport direction.

[0014] By adopting such a configuration, the diameter of the cooling roller is set to a specific dimension (3 to 12 times the dimension of the irradiation window in the substrate transport direction), so that the curvature of the transported flexible substrate can be made relatively small (the portion of the flexible substrate irradiated with plasma can be made relatively flat). Therefore, the temperature unevenness in the transport direction of the flexible substrate can be reduced. It is preferable to set the diameter of the cooling roller to 6 times or less the dimension of the irradiation window in the substrate transport direction, since this prevents the device from becoming unnecessarily large.

[0015] In the plasma baking apparatus according to the present invention, the width dimension of the cooling roller can be set to 0.5 to 3 times the dimension of the irradiation window in the width direction of the substrate.

[0016] By adopting such a configuration, the width dimension of the cooling roller is set within a specific range (0.5 to 3 times the dimension of the irradiation window in the width direction of the substrate), so that the size of the device can be prevented from becoming unnecessarily large. In particular, it is preferable to set the width dimension of the cooling roller to 2 times or less the dimension of the irradiation window in the width direction of the substrate.

[0017] In the plasma baking apparatus according to the present invention, the plasma irradiation distance from the irradiation window to the flexible substrate can be set to 1 mm or more and 300 mm or less.

[0018] By adopting such a configuration, the plasma irradiation distance from the irradiation window to the flexible substrate is set within a specific range (1 mm or more and 300 mm or less), so that stable plasma irradiation is possible. In addition, in consideration of the stability of plasma lighting, it is preferable to set the plasma irradiation distance from the irradiation window to the flexible substrate to 20 mm or more. In addition, it is preferable to set the plasma irradiation distance from the irradiation window to the flexible substrate to 140 mm or less, because the plasma can reliably reach the flexible substrate.

[0019] In the plasma baking apparatus according to the present invention, a cooling roller having a turbulent coolant flow path can be employed.

[0020] By adopting such a configuration, it is possible to increase the cooling efficiency of the flexible substrate, and to reduce temperature unevenness in the transport direction of the flexible substrate.

[0021] In the plasma baking apparatus according to the present invention, the surface roughness Ra of the cooling roller can be set to 0.005 μm or more and 10 μm or less.

[0022] By adopting such a configuration, the surface roughness Ra of the cooling roller is set within a specific range (0.005 μm or more and 10 μm or less), so that the transport efficiency and cooling efficiency of the flexible substrate can be improved. In addition, considering that finishing is performed by vertical polishing, it is preferable to set the surface roughness Ra of the cooling roller to 0.1 μm or more. In addition, it is preferable to set the surface roughness Ra of the cooling roller to 2 μm or more, since this further improves the cooling efficiency of the flexible substrate.

[0023] In the plasma baking apparatus according to the present invention, the microwave power per plasma generating device can be set to 100W or more and 6000W or less.

[0024] By adopting such a configuration, the microwave power per plasma generator is set within a specific range (100 W or more and 6000 W or less), so that the plasma can be lit stably. It is particularly preferable to set the microwave power per plasma generator to 300 W or more.

[0025] In the plasma baking apparatus according to the present invention, the pressure in the vacuum chamber during baking can be set to 0.1 Pa or more and 200 Pa or less.

[0026] By adopting such a configuration, the pressure in the vacuum chamber during firing is set within a specific range (0.1 Pa or more and 200 Pa or less), so that the plasma can be lit stably. In particular, it is preferable to set the pressure in the vacuum chamber during firing to 10 Pa or more and 100 Pa or less, because this allows the surface wave plasma of the reducing gas to be lit stably.

[0027] The plasma firing method according to the present invention is a method for performing a reduction sintering process with plasma on a flexible substrate on which a predetermined pattern is printed with ink containing a metal compound, and the reduction sintering process is performed using the plasma firing apparatus according to the present invention. As the metal compound, a metal oxide (e.g., copper oxide) can be used. As the flexible substrate, a substrate having a visible light transmittance of 80% or more measured in accordance with JIS K 7361-1:1997 can be used.

[0028] By adopting this method, the reduction sintering process is performed using the plasma firing device according to the present invention, so that the plasma can be irradiated uniformly over the entire width of the flexible substrate, and temperature unevenness in the width of the flexible substrate can be reduced, thereby making it possible to increase the processing efficiency while suppressing damage to the flexible substrate.

[0029] Furthermore, the method for forming a conductive pattern according to the present invention is a method for forming a conductive pattern on a flexible substrate by carrying out a reduction sintering treatment of a metal oxide using the plasma firing method according to the present invention. Effect of the Invention

[0030] According to the present invention, in a plasma sintering apparatus that performs a reduction sintering process on a flexible substrate using plasma, it is possible to increase the processing efficiency while suppressing damage to the flexible substrate by reducing the temperature unevenness of the flexible substrate. [Brief description of the drawings]

[0031] [Figure 1] FIG. 1 is an explanatory diagram for explaining the configuration of a plasma baking apparatus according to an embodiment of the present invention (a diagram showing the inside of a vacuum chamber as viewed from the side). [Diagram 2] FIG. 1 is an explanatory diagram for explaining the configuration of a plasma baking apparatus according to an embodiment of the present invention (a diagram showing the inside of a vacuum chamber as viewed from above). [Diagram 3] 1 is a graph showing temperature profiles from the center to the ends in the width direction of a flexible substrate in this embodiment and a comparative example. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0032] Hereinafter, embodiments of the present invention will be described with reference to the drawings. Note that the following embodiments are merely preferred application examples, and the scope of application of the present invention is not limited to these.

[0033] First, the configuration of a plasma baking device 1 according to this embodiment will be described with reference to Figures 1 and 2. The plasma baking device 1 is configured to perform a reduction sintering process using plasma on a flexible substrate S on which a predetermined pattern is printed with ink containing a metal compound, and includes a vacuum chamber 10, a pay-out roller 20, a wind-up roller 30, a cooling roller 40, a plasma generator 50, and the like, as shown in Figures 1 and 2.

[0034] The vacuum chamber 10 is a housing having a predetermined internal space, and is configured to perform plasma firing (reduction sintering process using plasma) in the internal space. The pressure in the internal space of the vacuum chamber 10 is set within a specific range (0.1 Pa to 200 Pa) during plasma firing so that the plasma can be stably ignited. In particular, it is preferable to set the pressure in the internal space of the vacuum chamber 10 during firing to 10 Pa to 100 Pa, since this allows the surface wave plasma of the reducing gas to be stably ignited.

[0035] 1 and 2, the vacuum chamber 10 is provided with two irradiation windows 11 for irradiating plasma from a plasma generating device 50 provided outside into the internal space. The irradiation window 11 has a substantially rectangular shape when viewed from the front (i.e., when viewed from the left or right side of the paper in FIGS. 1 and 2) and has a predetermined height dimension (dimension in the transport direction of the flexible substrate S) H as shown in FIG. W and a predetermined width dimension (the dimension in the width direction of the flexible substrate S) W WIn this embodiment, the vacuum chamber 10 is provided with two irradiation windows 11, but the vacuum chamber 10 may be provided with only one irradiation window 11. The shape of the irradiation window 11 as viewed from the front is not limited to a rectangular shape, and may be, for example, an elliptical shape.

[0036] As shown in FIG. 2, the irradiation window 11 has a width dimension W S Dimension W is longer than W The width dimension W of the irradiation window 11 extends along the width direction of the flexible substrate S. With this configuration, when the flexible substrate S is subjected to a reduction sintering process using plasma, the plasma can be uniformly irradiated over the entire width direction of the flexible substrate S, and temperature unevenness in the width direction of the flexible substrate S can be reduced. W The width dimension W of the flexible substrate S S It is preferable to set the width W of the flexible substrate S to 1.5 to 4.5 times, since this can further reduce the temperature unevenness in the width direction of the flexible substrate S. S It is preferable to have the width of the substrate extend along the substrate width direction with a dimension of 3.0 times or less, since this can prevent the size of the device from becoming unnecessarily large.

[0037] As shown in FIGS. 1 and 2, the plasma irradiation distance D from the irradiation window 11 to the flexible substrate S is P It is preferable to set the plasma irradiation distance D from the irradiation window 11 to the flexible substrate S to 1 mm or more and 300 mm or less, since this enables stable plasma irradiation. P It is preferable to set the plasma irradiation distance D to 20 mm or more. P It is preferable to set the plasma irradiation distance D to 140 mm or less, since the plasma can reliably reach the flexible substrate S. In the vacuum chamber 10 of the present embodiment, as shown in FIG. P An irradiation distance adjustment mechanism 12 is provided to adjust the irradiation distance.

[0038] 1 and 2, a payout roller 20, a winding roller 30, and a cooling roller 40 are installed in the internal space of the vacuum chamber 10. The payout roller 20 functions to pay out the flexible substrate S toward the cooling roller 40, and the winding roller 30 functions to wind up the flexible substrate S transported by the cooling roller 40. The payout roller 20 and the winding roller 30 may have any configuration as long as they perform the above functions, and their diameters and positions within the vacuum chamber 10 can be set appropriately depending on the scale and specifications of the plasma baking apparatus 1.

[0039] The cooling roller 40 functions to transport the flexible substrate S from the pay-out roller 20 to the take-up roller 30 and to cool the flexible substrate S. As shown in FIG. R The height dimension H of the irradiation window 11 W When the diameter D of the cooling roller 40 is set to 3 times or more and 12 times or less, the curvature of the flexible substrate S being transported can be made relatively small (i.e., the portion of the flexible substrate S irradiated with the plasma can be made relatively flat), and the temperature unevenness in the transport direction of the flexible substrate S can be reduced, which is preferable. R The height dimension H of the irradiation window 11 W It is preferable to set the value to 6 times or less, since this can prevent the device from becoming unnecessarily large in size.

[0040] As shown in FIG. 2, the width W R The width dimension W of the irradiation window 11 W It is preferable to set the width W of the cooling roller 40 to 0.5 times or more and 3 times or less, since this prevents the size of the device from becoming unnecessarily large. R The width dimension W of the irradiation window 11 WIt is preferable to set the surface roughness Ra of the cooling roller 40 to 0.005 μm or more and 10 μm or less, since this can improve the transport efficiency and cooling efficiency of the flexible substrate S. In this case, taking into consideration the finishing by vertical polishing, it is preferable to set the surface roughness Ra of the cooling roller 40 to 0.1 μm or more, and it is also preferable to set the surface roughness Ra of the cooling roller to 2 μm or more, since this further improves the cooling efficiency of the flexible substrate S.

[0041] A refrigerant flow path is provided near the surface of the cooling roller 40 to allow the cooling medium supplied from a refrigerant supply source (not shown) to flow. The position of the refrigerant flow path (depth from the surface of the cooling roller 40, etc.), the shape of the refrigerant flow path (whether it is formed in a spiral shape along the circumferential direction of the cooling roller 40 or formed in a meandering shape along the axial direction of the cooling roller 40, etc.), the cross-sectional area of ​​the refrigerant flow path, etc. can be appropriately determined according to the type of cooling medium and the scale and specifications of the plasma baking device 1. In this embodiment, the cooling roller 40 having a turbulent cooling solvent flow path is used. For example, by reducing the cross-sectional area of ​​the entire refrigerant flow path, the flow rate of the refrigerant in the entire refrigerant flow path can be increased, and the Reynolds number can be increased to generate a turbulent flow. By increasing the Reynolds number and generating a turbulent flow in this way, the cooling efficiency of the flexible substrate S can be increased, and the temperature unevenness in the transport direction of the flexible substrate S can be reduced.

[0042] The plasma generating device 50 functions to irradiate plasma from an irradiation window 11 provided in the vacuum chamber 10 to the flexible substrate S transported by the cooling roller 40. As shown in FIG. 2, the plasma generating device 50 in this embodiment is configured to irradiate plasma over the entire width of the flexible substrate S by introducing microwaves along the width of the flexible substrate S. This has the advantage of further reducing temperature unevenness in the width of the flexible substrate S. It is preferable to set the microwave power per plasma generating device 50 to 100 W or more and 6000 W or less, since plasma can be stably lit. In particular, it is preferable to set the microwave power per plasma generating device 50 to 300 W or more. The plasma generating device 50 is attached to the irradiation window 11 of the vacuum chamber 10 via a quartz plate 60.

[0043] Next, the plasma baking method according to the present embodiment will be described. The plasma baking method according to the present embodiment is a method of performing a reduction sintering process with plasma on a flexible substrate S on which a predetermined pattern has been printed with ink containing a metal compound, using a plasma baking device 1, and includes a method of forming a conductive pattern on the flexible substrate S by performing a reduction sintering process on the metal oxide contained in the ink (conductive pattern forming method).

[0044] First, a flexible substrate S on which a predetermined pattern is printed with ink containing a metal compound is prepared (substrate preparation step). As the metal compound, a metal oxide such as copper oxide can be used. As the flexible substrate S, a substrate having a visible light transmittance of 80% or more measured in accordance with JIS K 7361-1:1997 can be used. Next, the flexible substrate S prepared in the substrate preparation step is introduced into the internal space of the vacuum chamber 10 of the plasma baking device 1, and arranged so that it is unwound from the unwinding roller 20, passes through the cooling roller 40, and is wound up by the winding roller 30 (substrate arrangement step).

[0045] Next, a vacuum pump (not shown) is used to reduce the pressure in the internal space of the vacuum chamber 10 to within a specific range (for example, 10 Pa or more and 100 Pa or less), a cooling medium is supplied from a cooling medium supply source (not shown) to the cooling medium flow path of the cooling roller 40, and the plasma generator 50 is operated to introduce microwaves along the width direction of the flexible substrate S, thereby preparing to irradiate the flexible substrate S with plasma over the entire width direction (irradiation preparation step). In the irradiation preparation step, the microwave power per plasma generator 50 is set within a specific range (for example, 100 W or more and 6000 W or less).

[0046] Next, the flexible substrate S is transported by operating the payout roller 20, the cooling roller 40, and the take-up roller 30, while the flexible substrate S is irradiated with plasma from the plasma generator 50 through the irradiation window 11 to perform a reduction sintering process (firing process). By this firing process, a reduction sintering process of the metal compound contained in the pattern printed on the flexible substrate S is performed, and a conductive pattern can be formed.

[0047] In the plasma firing apparatus 1 according to the embodiment described above, the irradiation window 11 provided in the vacuum chamber 10 extends along the width direction of the flexible substrate S with a dimension longer than the width of the flexible substrate S, so that when performing reduction sintering treatment on the flexible substrate S with plasma, the plasma can be uniformly irradiated over the entire width direction of the flexible substrate S. Therefore, it is possible to reduce temperature unevenness in the width direction of the flexible substrate S, and it is possible to increase the treatment efficiency while suppressing damage to the flexible substrate S.

[0048] Furthermore, in the plasma baking apparatus 1 according to the embodiment described above, by introducing microwaves along the width direction of the flexible substrate S, plasma can be irradiated over the entire width direction of the flexible substrate S, thereby further reducing temperature unevenness in the width direction of the flexible substrate S.

[0049] In the plasma firing apparatus 1 according to the embodiment described above, the irradiation window 11 is set to a specific dimension (the width dimension W of the flexible substrate S).S (1.5 to 4.5 times the dimension of W) W Since the flexible substrate S extends in the width direction of the substrate, the temperature unevenness in the width direction of the flexible substrate S can be further reduced.

[0050] In the plasma baking apparatus 1 according to the embodiment described above, the diameter D of the cooling roller 40 R The dimension H W Since the heating temperature is set to 3 to 12 times the heating temperature, the curvature of the flexible substrate S being transported can be made relatively small (the portion of the flexible substrate S that is irradiated with the plasma can be made relatively flat). Therefore, the temperature unevenness in the transport direction of the flexible substrate S can be reduced.

[0051] In the plasma baking apparatus 1 according to the embodiment described above, the width W of the cooling roller 40 R Within a specific range (the dimension W W Since the size of the device 1 is set to be equal to or larger than 0.5 times and equal to or smaller than 3 times the size of the device 1, the device 1 can be prevented from becoming unnecessarily large.

[0052] In the plasma firing apparatus 1 according to the embodiment described above, the plasma irradiation distance D from the irradiation window 11 to the flexible substrate S is P Since the distance is set within a specific range (1 mm or more and 300 mm or less), stable plasma irradiation is possible.

[0053] In addition, in the plasma baking apparatus 1 according to the embodiment described above, the cooling roller 40 having a turbulent cooling solvent flow path is adopted, so that the cooling efficiency of the flexible substrate S can be improved and temperature unevenness in the transport direction of the flexible substrate S can be reduced.

[0054] Furthermore, in the plasma baking apparatus 1 according to the embodiment described above, the surface roughness Ra of the cooling roller 40 is set within a specific range (0.005 μm or more and 10 μm or less), thereby improving the transport efficiency and cooling efficiency of the flexible substrate S.

[0055] Furthermore, in the plasma baking apparatus 1 according to the embodiment described above, the microwave power per plasma generating device 50 is set within a specific range (100 W or more and 6000 W or less), so that the plasma can be lit stably.

[0056] Furthermore, in the plasma firing apparatus 1 according to the embodiment described above, the pressure in the vacuum chamber 10 during firing is set within a specific range (0.1 Pa or more and 200 Pa or less), so that the plasma can be lit stably.

[0057] Next, examples of the present invention and comparative examples will be described.

[0058] <Example> The plasma baking apparatus 1 according to this embodiment includes the components already described (vacuum chamber 10, pay-out roller 20, wind-up roller 30, cooling roller 40, plasma generator 50, quartz plate 60, etc.). W was set to 400 (mm), and the firing conditions were set as follows: Output: 3 (kW) Pressure: 40(Pa) Gas type: HeH2 Gas flow rate: 600 (sccm) Beam distance D P :80(mm) Cooling roller coolant temperature: 25(℃) -Substrate conveying speed: 1 (m / min)

[0059] The specifications of the flexible substrate S to be subjected to the reduction sintering treatment in this example were as follows: ·Material: PET Thickness: 50(μm) ·Emissivity: 0.78 Thermal conductivity: 0.31 (W / mK) Width dimension W S :300(mm)

[0060] That is, in this embodiment, the width dimension W of the flexible substrate S S (300 mm) than the width dimension W of the irradiation window 11 W (400 mm) was set to be longer. And, as a boundary condition, the heat transfer coefficient between the flexible substrate S and the cooling roll 40 was set to 80 (W / m 2 The temperature of the quartz plate 60 was set to 600 (° C.).

[0061] Under the above conditions, the temperature was measured at multiple positions along the width direction of the flexible base material S to be subjected to reduction sintering treatment. Specifically, the temperatures at the center position in the width direction of the flexible base material S (center), at a position 60 mm away from the center along the width direction (gap 1), at a position 100 mm away from the center along the width direction (gap 2), and at a position 150 mm away from the center along the width direction (end) were measured and were found to be 173°C, 171°C, 167°C, and 155°C, respectively. In addition to the temperature measurements, the view factor and heat flux (W / m 2 The results are shown in Table 1.

[0062] <Comparative Example 1> In Comparative Example 1, the width dimension W of the irradiation window 11 of the vacuum chamber 10 of the plasma baking apparatus 1 used in the embodiment was W Only the width dimension W of the irradiation window 11 of the vacuum chamber 10 was changed, and the other configurations were the same as those of the embodiment (the firing conditions, boundary conditions, and specifications of the flexible substrate S were also the same as those of the embodiment). W was set to 300 (mm). That is, in Comparative Example 1, the width dimension W S (300 mm) and the width dimension W of the irradiation window 11 W (300 mm) and were set to be the same.

[0063] Under these conditions, similarly to the examples, the temperature at the center of the flexible substrate S in the width direction and at positions 60 mm (gap 1), 100 mm (gap 2), and 150 mm (end) away from the center of the flexible substrate S in the width direction were measured, and were 170°C, 166°C, 154°C, and 125°C, respectively. The results are shown in Table 1.

[0064] <Comparative Example 2> In Comparative Example 2, the width dimension W of the irradiation window 11 of the vacuum chamber 10 of the plasma baking apparatus 1 used in the Example was also W Only the width dimension W of the irradiation window 11 of the vacuum chamber 10 was changed, and the other configurations were the same as those of the embodiment (the firing conditions, boundary conditions, and specifications of the flexible substrate S were also the same as those of the embodiment). W was set to 200 (mm). That is, in Comparative Example 2, the width dimension W S (300 mm) than the width dimension W of the irradiation window 11 W (200mm) was set to be shorter.

[0065] Under these conditions, similar to the examples, the temperature at the center of the flexible substrate S in the width direction and the temperatures at positions 60 mm (gap 1), 100 mm (gap 2), and 150 mm (end) away from the center of the flexible substrate S in the width direction were measured and found to be 162°C, 151°C, 122°C, and 78°C, respectively. The results are shown in Table 1.

[0066] [Table 1]

[0067] 3 shows temperature profiles of this example, comparative example 1, and comparative example 2, with the horizontal axis representing the distance from the center in the width direction of the flexible substrate S and the vertical axis representing the temperature of the flexible substrate S. In FIG. 3, the solid line graph shows the temperature profile of this example, the dashed line graph shows the temperature profile of comparative example 1, and the dashed line graph shows the temperature profile of comparative example 2.

[0068] As is apparent from Table 1 and FIG. 3, the width dimension W of the flexible substrate S S The width dimension W of the irradiation window 11 W In this embodiment, in which the width dimension W of the flexible substrate S is set to be longer, the temperature difference in the width direction of the flexible substrate S is at most about 18°C ​​(Fig. 3: solid line). S and the width dimension W of the irradiation window 11 W In Comparative Example 1, in which the temperature difference in the width direction of the flexible substrate S was set to be the same as that in Comparative Example 1, the temperature difference in the width direction of the flexible substrate S was a maximum of 45° C. (FIG. 3: dashed line), and the width dimension W S The width dimension W of the irradiation window 11 W In Comparative Example 2, in which the width dimension W of the flexible substrate S was set to be shorter, the temperature difference in the width direction of the flexible substrate S was a maximum of 84° C. (FIG. 3: dashed line). S The width dimension W of the irradiation window 11 W is set to be longer, it has become clear that when performing reduction sintering treatment on the flexible substrate S with plasma, the plasma can be uniformly irradiated over the entire width direction of the flexible substrate S, and temperature unevenness in the width direction of the flexible substrate S can be reduced.

[0069] The present invention is not limited to the above-mentioned embodiments, and even if a person skilled in the art appropriately modifies the design of the embodiments, the embodiment is included in the scope of the present invention as long as it has the characteristics of the present invention. In other words, the elements of the above-mentioned embodiments and their arrangement, materials, conditions, shapes, sizes, etc. are not limited to those exemplified, and can be appropriately modified. In addition, the elements of the above-mentioned embodiments can be combined to the extent technically possible, and the combination of these elements is also included in the scope of the present invention as long as it has the characteristics of the present invention. [Industrial Applicability]

[0070] INDUSTRIAL APPLICABILITY The present invention is useful in a plasma sintering apparatus that performs reduction sintering treatment on a flexible substrate using plasma, in that it reduces temperature unevenness in the flexible substrate, thereby suppressing damage to the flexible substrate and increasing treatment efficiency. [Explanation of symbols]

[0071] 1...Plasma firing device 10…Vacuum chamber 11...Irradiation window 20...Feed roller 30... Winding roller 40...Cooling roller 50...Plasma generator D P …Plasma irradiation distance D R …cooling roller diameter H W …Height of irradiation window (dimension in the substrate conveying direction) S…Flexible base material W R …Cooling roller width W S …Width dimension of flexible substrate W W …Width of irradiation window (dimension in the width direction of the substrate)

Claims

1. A plasma sintering apparatus configured to perform a reduction sintering process using plasma on a flexible substrate on which a predetermined pattern is printed using an ink containing a metal compound, A vacuum chamber; a payoff roller for paying off the flexible substrate within the vacuum chamber; a take-up roller for taking up the flexible substrate within the vacuum chamber; a cooling roller that conveys the flexible substrate from the pay-out roller to the take-up roller and cools the flexible substrate; a plasma generating device configured to irradiate plasma onto the flexible substrate transported by the cooling roller from an irradiation window provided in the vacuum chamber; The irradiation window extends along the width direction of the flexible substrate with a dimension longer than the width dimension of the flexible substrate.

2. The plasma baking apparatus according to claim 1 , wherein the plasma generating device is configured to irradiate the plasma over the entire width of the flexible substrate by introducing microwaves along the width of the flexible substrate.

3. The plasma firing apparatus according to claim 1 , wherein the irradiation window extends along the width direction of the flexible substrate with a dimension that is 1.5 to 4.5 times the width of the flexible substrate.

4. 2. The plasma baking device according to claim 1, wherein the diameter of the cooling roller is set to be 3 to 12 times the dimension of the irradiation window in the substrate transport direction.

5. 2. The plasma firing apparatus according to claim 1, wherein the width of the cooling roller is set to be 0.5 to 3 times the dimension of the radiation window in the width direction of the substrate.

6. 2. The plasma baking apparatus according to claim 1, wherein a plasma irradiation distance from the irradiation window to the flexible base material is set to be 1 mm or more and 300 mm or less.

7. The plasma baking apparatus of claim 1 , wherein the cooling roller has a turbulent coolant flow passage.

8. 2. The plasma baking apparatus according to claim 1, wherein the surface roughness Ra of the cooling roller is set to be 0.005 μm or more and 10 μm or less.

9. 2. The plasma baking apparatus according to claim 1, wherein the microwave power per one of said plasma generating devices is set to 100 W or more and 6000 W or less.

10. 2. The plasma firing apparatus according to claim 1, wherein the pressure in the vacuum chamber during firing is set to 0.1 Pa or more and 200 Pa or less.

11. A plasma sintering method for performing a reduction sintering process using plasma on a flexible substrate on which a predetermined pattern is printed using an ink containing a metal compound, comprising the steps of: A plasma sintering method, comprising the steps of: performing the reduction sintering treatment using the plasma sintering apparatus according to claim 1 .

12. The plasma firing method according to claim 11 , wherein the metal compound is a metal oxide.

13. The plasma firing method of claim 12, wherein the metal oxide is copper oxide.

14. The plasma firing method according to claim 11, wherein the flexible substrate has a visible light transmittance of 80% or more as measured in accordance with JIS K 7361-1:1997.

15. A method for forming a conductive pattern on a flexible substrate by performing a reduction sintering process of a metal oxide using the plasma sintering method according to claim 11.

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