Heating apparatus and heating method

Abstract

Provided is a heating apparatus capable of heating a local range. A heating apparatus 1 comprises: a microwave generator 10; a coaxial cable 20 for transmitting generated microwaves; and a microwave irradiation device 30 for emitting the transmitted microwaves. The microwave irradiation device 30 is provided with: an inner line 31; first and second outer lines 32 and 33 disposed on both sides of the inner line 31 with a gap therebetween; and a connection line 34 for connecting tips of the first and second outer lines 32 and 33, which are ends on the opposite side from ends on the microwave introduction side.

Description

Heating Apparatus and Heating Method

[0001] The present invention relates to a heating apparatus that heats an object to be heated by irradiating microwaves to the object, a heating method, and the like.

[0002] In manufacturing, commerce and various other industries, diverse processes involve heating. Heating wires and the like are widely used as heating means.

[0003] These conventional heating means heat the entire object to be heated. The inventors have found that if heating within a local range of about several millimeters to several centimeters can be performed, the potential for quality improvement, cost reduction and other benefits in various industries will be expanded.

[0004] The present invention has been made in view of such circumstances, and an object thereof is to provide a heating apparatus, a heating method or an application thereof that enables heating within a local range of about several millimeters to several centimeters.

[0005] In order to solve such a problem, a microwave irradiation apparatus according to a first aspect of the present invention includes: an inner line; first and second outer lines arranged with intervals on both sides of the inner line; and a connection line connecting first and second tip ends which are ends of the first and second outer lines on opposite sides to a microwave introduction side.

[0006] Furthermore, a microwave irradiation apparatus according to a second aspect of the present invention is the microwave irradiation apparatus according to the first aspect, further comprising one or more resistors connecting the inner line to at least any one of the first and second outer lines and the connection line.

[0007] Furthermore, a microwave irradiation apparatus according to a third aspect of the present invention is the microwave irradiation apparatus according to the first or second aspect, further comprising a dielectric substrate, wherein the inner line, the first and second outer lines, and the connection line are each arranged on the substrate.

[0008] Furthermore, a microwave irradiation device according to a fourth aspect of the present invention is a microwave irradiation device according to any of the first to third aspects, wherein the inner line and the microwave introduction ends of the first and second outer lines are connected to a coaxial cable, and the line width and height of the inner line, and the distance between the inner line and the first and second outer lines are determined so as to match the impedance between the microwave irradiation device and the coaxial cable.

[0009] Furthermore, a microwave irradiation device according to a fifth aspect of the present invention is a microwave irradiation device according to any of the first to fourth aspects, comprising a microwave generator for generating microwaves, and transmission lines for transmitting the microwaves generated by the microwave generator to the inner line and the microwave introduction end of the first and second outer lines of the microwave irradiation device, respectively, and is configured to heat an object to be heated by irradiating it with microwaves from the microwave irradiation device.

[0010] Furthermore, a semiconductor wafer polishing apparatus according to a sixth aspect of the present invention comprises a chuck table that can hold and rotate a semiconductor wafer, a polishing pad for polishing the surface of the semiconductor wafer, a holding unit for holding the polishing pad, a supply unit for supplying polishing liquid to the surface, and a heating apparatus according to a fifth aspect for heating the surface by irradiating it with microwaves.

[0011] Furthermore, the retread tire manufacturing apparatus according to the seventh aspect of the present invention comprises a holding unit for holding a base tire, and a heating device according to claim 5, which heats the unvulcanized rubber by irradiating it with microwaves from the outer circumference side of the tread rubber, which is placed on the outer circumference surface of the base tire via unvulcanized rubber, thereby vulcanizing and bonding the base tire and the tread rubber.

[0012] Furthermore, an eighth aspect of the present invention relates to a method for heating an object to be heated, comprising the steps of supplying microwaves to the inner line, the first and second outer lines, and the microwave introduction side ends of the first and second outer lines, in a microwave irradiation device comprising an inner line, first and second outer lines arranged at intervals on both sides of the inner line, and connecting lines connecting the first and second tip ends, which are the ends of the first and second outer lines opposite to the microwave introduction side, respectively, and irradiating the object to be heated with microwaves from the microwave irradiation device.

[0013] Furthermore, the heating method according to the ninth aspect of the present invention is the heating method according to the eighth aspect, wherein the object to be heated is a semiconductor wafer.

[0014] Furthermore, a method for manufacturing a semiconductor device according to the tenth aspect of the present invention is a method for manufacturing a semiconductor device using a semiconductor wafer, comprising the step of heating the semiconductor wafer by the heating method of the eighth aspect.

[0015] Furthermore, a semiconductor wafer polishing method according to the eleventh aspect of the present invention includes the steps of: rotating a chuck table holding the semiconductor wafer; supplying a polishing liquid to the surface of the semiconductor wafer; polishing the surface by bringing a polishing pad into contact with the surface; and heating the surface by irradiating it with microwaves from a heating device according to the fifth aspect.

[0016] Furthermore, a method for manufacturing a retread tire according to the twelfth aspect of the present invention includes the steps of: placing tread rubber on the outer surface of a base tire via unvulcanized rubber; and using a heating device according to the fifth aspect, irradiating the unvulcanized rubber from the outer surface of the tread rubber with microwaves to heat it and vulcanize and bond the base tire and the tread rubber.

[0017] According to one aspect of the present invention, a localized area of ​​several millimeters to several centimeters can be heated by microwaves.

[0018] A schematic diagram showing the configuration of a heating device according to Embodiment 1 of the present invention; a plan view of a microwave irradiation device according to the same embodiment; a front view of a microwave irradiation device according to the same embodiment; a perspective view of a microwave irradiation device according to the same embodiment; a graph showing the relationship between the distance between the inner line and the first and second outer lines and characteristic impedance in the same embodiment; a graph showing the relationship between the height of the inner line and characteristic impedance in the same embodiment; a graph showing the relationship between resistance length and reflectance in the same embodiment; a graph showing the relationship between resistance length and power density in the same embodiment; a graph showing the change in the electric field in the x-axis direction in the same embodiment; a graph showing the change in the electric field in the y-axis direction in the same embodiment; a graph showing the change in the electric field in the z-axis direction in the same embodiment; a perspective view showing the electric field distribution near the microwave irradiation device in the same embodiment; a cross-sectional view showing the electric field distribution near the microwave irradiation device in the same embodiment; a schematic diagram showing the configuration of a SiC substrate polishing device according to Embodiment 2 of the present invention; a schematic diagram showing the configuration of a retread tire manufacturing device according to Embodiment 3 of the present invention.

[0019] The heating device and the like according to the present invention will be described below using embodiments. In the following embodiments, components denoted by the same reference numerals are the same or equivalent, and their further description may be omitted.

[0020] (Embodiment 1) A heating device and heating method according to Embodiment 1 of the present invention will be described with reference to the drawings. The heating device according to this embodiment can heat a localized area of ​​several millimeters to several centimeters by irradiating it with microwaves.

[0021] Figure 1 is a schematic diagram showing the configuration of the heating device 1 according to this embodiment. Figures 2A and 2B are a plan view and a front view, respectively, of the microwave irradiation device 30 according to this embodiment. Figure 3 is a perspective view of the microwave irradiation device 30.

[0022] The heating device 1 according to this embodiment comprises a microwave generator 10 that generates microwaves, a transmission line 20 such as a coaxial cable that transmits the microwaves generated by the microwave generator 10, and a microwave irradiation device 30 that irradiates the object to be heated with the microwaves transmitted by the coaxial cable 20. The heating device 1 is configured to heat the object to be heated by irradiating the object to be heated with microwaves from the microwave irradiation device 30.

[0023] In the heating device 1 according to this embodiment, microwaves can be irradiated onto a localized area, such as a few millimeters to a few centimeters, to heat the object to be heated. Therefore, in addition to being used for microwave heating in closed systems such as inside a container, the heating device 1 can also be used for microwave heating in open systems outside a container, without microwave leakage being a major problem. For this reason, many applications of the heating device 1 according to this embodiment can be considered. As examples, heating of a SiC substrate using the heating device 1 during polishing of a SiC substrate, and heating for vulcanization bonding using the heating device 1 during the manufacture of retreaded tires will be described later in Embodiments 2 and 3, respectively. The object to be heated by the heating device 1 irradiating with microwaves may be, for example, a solid, a liquid, or a gas. Examples of solids include semiconductor wafers such as SiC substrates, GaN substrates, wafers having a GaN layer, and diamond substrates, where "substrate" may refer to a wafer processed into a disc shape. SiC and GaN have relatively high microwave absorption capabilities and are highly suitable as objects to be heated. Furthermore, semiconductor wafers with an adhesive layer can also be cited as objects to be heated.

[0024] The microwave generator 10 generates microwaves that are supplied to the microwave irradiation device 30. The microwave generator 10 may generate microwaves using, for example, a magnetron, klystron, gyrotron, or semiconductor element. Generating microwaves using a semiconductor element may, for example, involve oscillating microwaves using the semiconductor element, or amplifying microwaves using the semiconductor element. The frequency band of the microwaves may be, for example, around 433.92 MHz, 915 MHz, 2.45 GHz, and 5.8 GHz, or it may be any other frequency band within the range of 300 MHz to 300 GHz.

[0025] The coaxial cable 20 transmits microwaves generated by the microwave generator 10 to the microwave irradiation device 30. As shown in Figure 2A, the coaxial cable 20 may have, for example, an inner conductor 21, an insulator 22 provided around the inner conductor 21, an outer conductor 23 provided on the outer periphery of the insulator 22, and a covering 24 covering the outer surface of the outer conductor 23.

[0026] The microwave irradiation device 30 irradiates microwaves and comprises an inner line 31, first and second outer lines 32 and 33 arranged on both sides of the inner line 31, and a connecting line 34 connecting the first and second tip portions 32b and 33b, which are the ends of the first and second outer lines 32 and 33 opposite to the microwave introduction side. If necessary, the microwave irradiation device 30 may further include a resistor 35 connecting the tip portion 31b, which is the end of the inner line 31 opposite to the microwave introduction side, to the connecting line 34. Here, the connections between each line and between each line and the resistor 35 are electrical connections. Furthermore, if necessary, the microwave irradiation device 30 may further include a dielectric substrate 36.

[0027] In this embodiment, as shown in Figures 2A, 2B, and 3, the xyz coordinate system, which is a three-dimensional Cartesian coordinate system, is set such that the origin is the center in the longitudinal and width directions on the upper surface of the inner track 31, the longitudinal direction of the inner track 31 is the x-axis, the normal direction of the substrate 36 is the z-axis, and the direction perpendicular to the x and z axes is the y-axis. The upper surface of the inner track 31 is the surface of the inner track 31 that is parallel to the substrate 36 and does not come into contact with the substrate 36. The same applies to the other tracks. Furthermore, the positive direction of the x-axis is the direction from the end 31a to the tip 31b of the inner track 31, the positive direction of the y-axis is the direction from the inner track 31 to the second outer track 33, and the positive direction of the z-axis is the direction from the surface of the substrate 36 where the inner track 31 etc. are not arranged to the surface where the inner track 31 etc. are arranged.

[0028] First and second outer tracks 32 and 33 are arranged on both sides of the inner track 31, spaced apart. For example, the inner track 31, the first outer track 32, the second outer track 33, and the connecting track 34 may each be tracks with any arbitrary linear shape, tracks that extend in a straight line, or tracks that have a constant width and height independently. The width of each track is the width in the direction perpendicular to the longitudinal direction in a plan view. The height of each track is the height from the surface in contact with the substrate 36 to the top surface. Preferably, the spacing between the inner track 31 and the first and second outer tracks 32 and 33 is constant in at least a portion of the longitudinal direction of the inner track 31. As an example, this spacing may be constant over the entire longitudinal direction of the inner track 31, as shown in Figure 2A. The inner track 31 and the first and second outer tracks 32 and 33 may also be arranged parallel to each other. Furthermore, it is preferable that the distance between the inner track 31 and the first outer track 32 is equal to the distance between the inner track 31 and the second outer track 32.

[0029] Furthermore, the local area irradiated by microwaves from the microwave irradiation device 30 changes depending on the longitudinal length of the inner line 31. Therefore, it is preferable to determine the longitudinal length of the inner line 31 so that microwaves are irradiated over a desired area.

[0030] It is preferable that the first and second outer tracks 32 and 33 have the same length and line width in a plan view. It is also preferable that they are at the same height. The inner track 31 and the first and second outer tracks 32 and 33 may or may not have the same line width. In the latter case, for example, the line width of the first and second outer tracks 32 and 33 may be greater than the line width of the inner track 31. It is also preferable that the inner track 31 and the first and second outer tracks 32 and 33 are at the same height. In this embodiment, the case in which the inner track 31 and the first and second outer tracks 32 and 33 have the same line width and height will be mainly described. Furthermore, it is preferable that at least the first and second outer tracks 32 and 33 are present in the range in which the inner track 31 exists in the x-axis direction. In this embodiment, as an example, the x-axis values ​​of the inner line 31 and the microwave introduction ends 31a, 32a, and 33a of the first and second outer lines 32 and 33 are the same, and the x-axis values ​​of the first and second tip portions 32b and 33b of the first and second outer lines 32 and 33 are greater than the x-axis value of the tip portion 31b of the inner line 31 will be mainly described.

[0031] The inner line 31 and the microwave introduction ends 31a, 32a, and 33a of the first and second outer lines 32 and 33 are each connected to the coaxial cable 20. That is, the microwaves generated by the microwave generator 10 are transmitted by the coaxial cable 20 to the inner line 31 and the ends 31a, 32a, and 33a of the first and second outer lines 32 and 33, respectively. More specifically, as shown in Figure 2A, the end 31a of the inner line 31 may be connected to the internal conductor 21 of the coaxial cable 20, and the ends 32a and 33a of the first and second outer lines 32 and 33 may be connected to the external conductor 23 of the coaxial cable 20, respectively. It is preferable that the coaxial cable 20 and the first and second outer lines 32 and 33 are connected such that the microwave phases at the ends 32a and 33a are the same. Therefore, as an example, the outer conductor 23 and the ends 32a and 33a may be connected by connecting wires of the same length.

[0032] The connecting line 34 may be arranged such that its longitudinal direction is perpendicular to the longitudinal direction of the inner line 31, etc., as shown in Figure 2A. The inner line 31 and the connecting line 34 may have the same line width and the same height, for example. This embodiment will mainly describe this case. The resistor 35 may connect, for example, the center of the connecting line 34 in the longitudinal direction to the tip 31b of the inner line 31, or it may connect a position other than the center of the connecting line 34 in the longitudinal direction to the tip 31b of the inner line 31. The microwave irradiation device 30 may also include, for example, one or more resistors 35 that connect the inner line 31 to at least one of the first and second outer lines 32, 33 and the connecting line 34. Thus, the inner line 31 and the other lines may be connected by a single resistor 35 or by multiple resistors 35. As an example, the microwave irradiation device 30 may be equipped with one resistor 35 connecting the inner line 31 and the first outer line 31 at a certain location in the x-axis direction, or as another example, it may be equipped with two resistors 35 connecting the inner line 31 and the first and second outer lines 31 and 32, respectively, at a certain location in the x-axis direction. In order to output a more uniform microwave, it is preferable that the inner line 31 and both the first and second outer lines 31 and 32 are connected by two resistors 35, rather than the inner line 31 and one of the first and second outer lines 31 and 32 being connected by one resistor 35. Furthermore, it is preferable that the length from the location where the resistor 35 is connected in the longitudinal direction of the inner line 31 to the end 31a on the microwave introduction side be at least 1 / 4 wavelength of the microwave propagating in that region of the inner line 31. Otherwise, microwaves will not be properly introduced into the inner line 31. Furthermore, in the x-axis direction, microwaves are mainly output from the region from the microwave introduction end 31a, 32a, 33a to the point where the resistor 35 is connected to the inner line 31 and the other lines.Therefore, in order to output microwaves from a wider area, it is preferable for the resistor 35 to connect a point close to the tip 31b of the inner line 31 to another line, and it is even more preferable to connect the tip 31b of the inner line 31 to the connecting line 34, as shown in Figures 2A and 3.

[0033] The materials of the inner track 31, the first and second outer tracks 32 and 33, and the connecting track 34 are preferably the same. Furthermore, these materials are preferably metals with high electrical conductivity. Metals with high electrical conductivity may be, for example, copper or silver.

[0034] For example, the resistance value per unit length in the longitudinal direction of the resistor 35 may be greater than the resistance value per unit length in the longitudinal direction of the inner line 31. The longitudinal direction of the resistor 35 shown in Figures 2A and 3 may also be the x-axis direction of the resistor 35. As an example, the electrical resistivity of the resistor 35 may be greater than that of the inner line 31. As another example, the electrical resistivity of the resistor 35 may be the same as that of the inner line 31, but the cross-sectional area perpendicular to the longitudinal direction of the resistor 35 may be smaller than the cross-sectional area perpendicular to the longitudinal direction of the inner line 31. If the microwave irradiation device 30 is equipped with a resistor 35, more uniform microwave irradiation can be achieved, but the microwave irradiation device 30 does not have to be equipped with a resistor 35. Furthermore, from the viewpoint of achieving more uniform microwave irradiation, it is preferable that the resistor 35 connects the center in the longitudinal direction of the connecting line 34 to the tip 31b of the inner line 31, as shown in Figures 2A and 3.

[0035] The inner track 31, the first and second outer tracks 32 and 33, the connecting track 34, and the resistor 35 may, for example, have a line-symmetric shape with respect to the x-axis in a plan view. Alternatively, they may have a plane-symmetric shape with respect to the xz-plane where y=0. This embodiment will mainly describe the latter case.

[0036] The inner line 31, the first and second outer lines 32 and 33, and the connecting line 34 may each be arranged on a dielectric substrate 36. The substrate 36 is usually a planar substrate. As shown in Figure 2A, in a plan view, the area of ​​the substrate 36 may be larger than the smallest rectangular area containing each line, or the two areas may coincide. Each line may, for example, be arranged on the surface of the dielectric substrate 36, or at least a part of it may be embedded inside the substrate 36. Furthermore, the inner line 31, the first and second outer lines 32 and 33, and the connecting line 34 may each be arranged on the same side of the dielectric substrate 36, for example, as shown in Figures 2A, 2B, and 3, or they may not be. In the latter case, for example, some of the inner line 31, the first and second outer lines 32 and 33, and the connecting line 34 may be arranged on the first side of the substrate 36, and the other lines may be arranged on the second side of the substrate 36. The second side is the side opposite to the first side. As an example, the inner line 31 may be arranged on the first side of the substrate 36, and the first and second outer lines 32 and 33, and the connecting line 34 may be arranged on the second side of the substrate 36. In this case, the resistor 35 may connect the inner line 31 and the other lines via the substrate 36. In this embodiment, the case in which each line is arranged on the same side of the substrate 36 will be mainly described.

[0037] The microwave irradiation device 30 according to this embodiment can also be considered as a coplanar line comprising a signal line corresponding to the inner line 31 and a pair of ground lines corresponding to the first and second outer lines 32 and 33, wherein one end of the pair of ground lines is short-circuited by a line corresponding to the connecting line 34, and the short-circuiting line and one end of the signal line are connected by a resistor.

[0038] In order to ensure that microwaves transmitted through the coaxial cable 20 are introduced into the microwave irradiation device 30 with low reflectivity, it is preferable to match the impedance of the coaxial cable 20 and the microwave irradiation device 30. This impedance matching will be explained below. The impedance of the coaxial cable 20 is usually 50Ω, so the explanation below will mainly focus on the case where the impedance of the two is matched by setting the characteristic impedance of the microwave irradiation device 30 to 50Ω. However, if the impedance of the coaxial cable 20 is other than 50Ω, it goes without saying that the impedance of the two may be matched by setting the characteristic impedance of the microwave irradiation device 30 to a value other than 50Ω. Furthermore, for example, if the reflectivity of the microwaves introduced from the coaxial cable 20 to the microwave irradiation device 30 does not exceed 10%, it may be considered that the impedances of the coaxial cable 20 and the microwave irradiation device 30 are matched.

[0039] The properties of the microwave irradiation device 30 verified by simulation will be described below with reference to Figures 4 to 12. In this simulation, as shown in Figures 2A and 2B, the length of the inner line 31 in the x-axis direction is A, the line width of the inner line 31 in the y-axis direction is B, the height of the inner line 31 and the first and second outer lines 32 and 33 in the z-axis direction is C, the distance between the inner line 31 and the first and second outer lines 32 and 33 in the y-axis direction is D, and the length of the resistor 35 in the x-axis direction (hereinafter sometimes referred to as "resistor length") is E. In the following explanation, the resistance value of the resistor 35 will be changed by changing the resistor length E. That is, the longer the resistor length E, the higher the resistance value from the connection point of the resistor 35 with the inner line 31 to the connection point with the connecting line 34. Also, when the resistor length E is changed, the lengths of the first and second outer lines 32 and 33 in the x-axis direction will be changed accordingly. In this simulation, all A lines are set to 100 mm, and the microwave frequency is set to 2.45 GHz. Furthermore, the line width and height of the inner line 31 and the first and second outer lines 32 and 33 are made the same. In this simulation, it is assumed that each line is positioned on the surface of the dielectric substrate 36.

[0040] Figure 4 is a diagram of the simulation results showing the relationship between the spacing D and the characteristic impedance of the microwave irradiation device 30. In graph 101, B = 0.7 mm and C = 0.5 mm, and in graph 102, B = 0.8 mm and C = 0.6 mm. As shown in graphs 101 and 102 of Figure 4, the characteristic impedance of the microwave irradiation device 30 increases as the spacing D increases. Therefore, the characteristic impedance of the microwave irradiation device 30 can be changed by changing the spacing D. For example, in graph 101, by setting the spacing D to 0.5 mm, and in graph 102, by setting the spacing D to 0.6 mm, the characteristic impedance of the microwave irradiation device 30 can be set to 50 Ω, thereby achieving impedance matching between the coaxial cable 20 and the microwave irradiation device 30.

[0041] Figure 5 shows the simulation results illustrating the relationship between height C and the characteristic impedance of the microwave irradiation device 30. In graph 111, B = 0.8 mm and D = 0.3 mm; in graph 112, B = 0.7 mm and D = 0.3 mm; in graph 113, B = 0.8 mm and D = 0.5 mm; in graph 114, B = 0.7 mm and D = 0.5 mm; in graph 115, B = 0.8 mm and D = 0.7 mm; and in graph 116, B = 0.7 mm and D = 0.7 mm. As shown in graphs 111 to 116 of Figure 5, the characteristic impedance of the microwave irradiation device 30 decreases as the height C increases. Therefore, the characteristic impedance of the microwave irradiation device 30 can be changed by changing the height C. For example, in graph 114, impedance matching can be achieved by setting the height C to 0.5 mm.

[0042] Furthermore, referring to the graph in Figure 5, it can be seen that the characteristic impedance of the microwave irradiation device 30 decreases as the line width B increases. Therefore, it can be seen that the characteristic impedance of the microwave irradiation device 30 can be changed by changing the line width B.

[0043] As described above, since the characteristic impedance of the microwave irradiation device 30 changes in accordance with the line width B, the height C, and the interval D, the line width B and the height C of the inner line 31, and the interval D between the inner line 31 and the first and second outer lines 32, 33 may be determined so that the impedance between the coaxial cable 20 and the microwave irradiation device 30 is matched. By using the microwave irradiation device 30 having the line width B, the height C, and the interval D determined in this way, the impedance between the coaxial cable 20 and the microwave irradiation device 30 can be matched. By matching the impedance of the two, microwaves can be propagated to each line of the microwave irradiation device 30 without generating a standing wave. Further, when the inner line 31 and the connection line 34 are connected via the resistor 35, uniform heat generation along the inner line 31 and the first and second outer lines 32, 33 can be achieved.

[0044] FIG. 6 is a diagram showing simulation results illustrating the relationship between the resistance length E and the reflectance of microwaves introduced into the microwave irradiation device 30. In graph 121, B = 0.7 mm, C = 0.5 mm, D = 0.5 mm; in graph 122, B = 0.8 mm, C = 0.6 mm, D = 0.6 mm; and in graph 123, B = 0.8 mm, C = 0.6 mm, D = 0.5 mm. Note that in FIG. 6, it is assumed that the impedance between the coaxial cable 20 and the microwave irradiation device 30 is matched even when the resistance length E is changed. As shown in graphs 121 to 123 of FIG. 6, the smaller the resistance length E, that is, the smaller the resistance value of the resistor 35 in the longitudinal direction, the lower the reflectance. It can be seen that the reflectance is lowest when the resistance length E is 1 mm. Therefore, in the simulations of FIGS. 8 to 12, the resistance length E was all set to 1 mm.

[0045] Figure 7 is a simulation result showing the relationship between the resistance length E and the power density at a position 10 cm away from the inner line 31 when 100 W of microwaves is supplied to a microwave irradiation device 30 with B = 0.7 mm, C = 0.5 mm, and D = 0.5 mm. Graph 131 shows the relationship between the resistance length E and the power density at the position (x, y, z) = (15 cm, 0, 0), Graph 132 shows the relationship between the resistance length E and the power density at the position (x, y, z) = (-15 cm, 0, 0), Graph 133 shows the relationship between the resistance length E and the power density at the position (x, y, z) = (0, 15 cm, 0), and Graph 134 shows the relationship between the resistance length E and the power density at the position (x, y, z) = (0, 0, 15 cm). Graphs 131-134 show that at a distance of 10 cm from the inner track 31, the microwave leakage rate is 0.1 mW / cm². ２ It has become smaller, and the microwave leakage threshold is 1 mW / cm². ２ It can be confirmed that the microwaves are significantly weaker. This indicates that the microwaves emitted from the microwave irradiation device 30 do not spread over a wide area. Therefore, even if microwave irradiation using the microwave irradiation device 30 is performed in an open system, objects and people located at a certain distance from the microwave irradiation device 30 will have almost no effect from the microwaves.

[0046] Furthermore, from graph 134 in Figure 7, it can be seen that in order to achieve microwave irradiation over a wider area in the z-axis direction, that is, in the direction normal to the substrate 36, the resistance length E, that is, the resistance value in the longitudinal direction of the resistor 35, should be increased. On the other hand, as mentioned above, increasing the resistance length E increases the reflectivity. Therefore, in order to broaden the microwave reach in the z-axis direction without increasing the resistance length E, it can be seen that the power of the microwaves introduced into the microwave irradiation device 30 should be increased.

[0047] FIGS. 8, 9, and 10 are each diagrams showing simulation results of the electric field intensity of microwaves along the x-axis, y-axis, and z-axis when 100 W of microwaves are supplied to the microwave irradiation device 30. In FIGS. 8, 9, and 10, graphs 141, 151, and 161 have B = 0.7 mm, C = 0.5 mm, and D = 0.5 mm; graphs 142, 152, and 162 have B = 0.8 mm, C = 0.6 mm, and D = 0.6 mm; and graphs 143, 153, and 163 have B = 0.8 mm, C = 0.6 m, and D = 0.5 mm.

[0048] From FIG. 8, it can be confirmed that microwaves with uniform electric field intensity along the longitudinal direction of the inner line 31 are output from the microwave irradiation device 30. Further, from FIGS. 9 and 10, it can also be confirmed that the electric field intensity of the microwaves output from the microwave irradiation device 30 is high only in the vicinity of the inner line 31 and the first and second outer lines 32, 33 in the y-axis direction and z-axis direction, and the electric field intensity attenuates by about one order of magnitude even at a position several millimeters away from the inner line 31 and the like. From these results, it can be understood that the microwaves output from the microwave irradiation device 30 are localized in the vicinity of the inner line 31 and the like.

[0049] FIGS. 11 and 12 are each diagrams showing simulation results of the electric field distribution on the xy plane at z = 0, and the direction and intensity of the electric field on the yz plane at x = 0, when 100 W of microwaves are supplied to the microwave irradiation device 30. In FIGS. 11 and 12, B = 0.7 mm, C = 0.5 mm, and D = 0.5 mm. As shown in FIG. 11, it can be seen that the electric field in the vicinity of the inner line 31 is uniform. Further, as shown in FIG. 12, it can be seen that the z-axis direction component of the electric field is dominant on the upper side of the inner line 31 and the first and second outer lines 32, 33, and the y-axis direction component of the electric field is dominant between the inner line 31 and the first and second outer lines 32, 33. Further, from FIG. 12, it can be confirmed that the microwaves output from the microwave irradiation device 30 are directed more in the z-axis direction than in the y-axis direction.

[0050] Next, microwave heating of an object to be heated using the heating device 1 according to this embodiment will be described. Since the microwaves output from the microwave irradiation device 30 are localized in the vicinity of each line, the microwave irradiation device 30 or the object to be heated should be positioned so that the object to be heated is within the range irradiated by the microwaves from the microwave irradiation device 30. In addition, since the microwave irradiation device 30 irradiates microwaves directed in the z-axis direction, it is preferable that the object to be heated is located in the positive z-axis direction from the inner line 31. Then, the microwave generator 10 starts generating microwaves, and the generated microwaves are supplied to the introduction end 31a, 32a, and 33a of the microwave irradiation device 30 so that the microwaves from the microwave irradiation device 30 irradiate the object to be heated. Since the microwaves irradiated from the microwave irradiation device 30 are localized, microwave irradiation can also be performed in an open system. Therefore, microwave heating by the heating device 1 can be performed in spaces where people are working, such as factories, shops, or homes, without the need to use metal containers or other means to shield the microwaves.

[0051] For example, if the type of object to be heated and its heating temperature are predetermined, the desired heating can be achieved by supplying microwaves of a predetermined power from the microwave generator 10 to the microwave irradiation device 30. Another example is that the temperature of the object to be heated is measured, and feedback control is performed on the microwave generation by the microwave generator 10 using the measured temperature, so that the object to be heated is heated to a set temperature. In this case, the heating device 1 may further include, for example, a temperature acquisition unit that acquires the temperature of the object to be heated, and a control unit that controls the microwave generator 10 using the temperature acquired by the temperature acquisition unit. The temperature acquisition unit may be, for example, a temperature sensor, or it may be a unit that accepts the temperature acquired by the temperature sensor.

[0052] As described above, with the heating device 1 and heating method according to this embodiment, microwaves can be localized by irradiating the object to be heated with microwaves output from the microwave irradiation device 30, and a localized area of ​​several millimeters to several centimeters can be microwave-heated. For this reason, microwave heating can be performed in an open system, for example, in a factory. Furthermore, when resistors 35 are connected to the inner line 31 and the connecting line 34, a uniform electric field is formed near the inner line 31 and the first and second outer lines 32 and 33 of the microwave irradiation device 30, thus enabling uniform heating. In this way, localized heating can be performed by using the heating device 1, and if the microwave irradiation device 30 is equipped with resistors 35, uniform heating can also be performed, making it easy to heat only a part of an object in an open system, for example.

[0053] Furthermore, by determining the line width and height of the inner line 31 of the microwave irradiation device 30, as well as the spacing between the inner line 31 and the first and second outer lines 32 and 33, so that the impedance of the coaxial cable 20 and the microwave irradiation device 30 are matched, microwaves can be appropriately supplied from the coaxial cable 20 to the microwave irradiation device 30, thereby achieving more efficient heating.

[0054] In this embodiment, the case in which an object to be heated is heated by irradiating it with microwaves from the microwave irradiation device 30 has been mainly described. However, the microwaves irradiated from the microwave irradiation device 30 may also be used for purposes other than heating, such as chemical reactions, drying, decomposition, detoxification, sterilization, and chemical recycling.

[0055] (Embodiment 2) An SiC substrate polishing apparatus and SiC substrate polishing method according to Embodiment 2 of the present invention will be described with reference to the drawings. The SiC substrate polishing apparatus according to this embodiment heats the SiC substrate using the heating apparatus according to Embodiment 1. The SiC substrate polishing apparatus and SiC substrate polishing method according to this embodiment can be applied to semiconductor device manufacturing processes other than the polishing process, such as the annealing process.

[0056] Conventionally, before fabricating devices on a single-crystal SiC (silicon carbide) substrate, the surface of the SiC substrate is planarized by polishing it with a polishing pad while supplying a polishing solution. It is known that heating the SiC substrate during this polishing process can improve polishing efficiency and shorten polishing time. However, when heating the SiC substrate using conventional heating methods such as electric heating wires, the SiC substrate is heated via the polishing solution present on its surface, leading to problems such as the evaporation of the polishing solution. Heating the surface of the SiC substrate with microwaves is also conceivable, but conventional microwave heating is performed in closed systems. If the SiC substrate polishing equipment is placed in a closed system such as a container, the workability of the SiC substrate polishing is significantly reduced, and therefore microwave heating has not been adopted.

[0057] The SiC substrate polishing apparatus and SiC substrate polishing method according to this embodiment can provide a SiC substrate polishing apparatus and SiC substrate polishing method that can heat the SiC substrate with microwaves, which was previously difficult, when polishing the SiC substrate in an open system.

[0058] Figure 13 is a schematic diagram showing the configuration of the SiC substrate polishing apparatus 50 according to this embodiment. The SiC substrate polishing apparatus 50 according to this embodiment includes a chuck table 52 that can hold and rotate a SiC substrate 51, a polishing pad 53 for polishing the surface of the SiC substrate 51, a holding unit 54 for holding the polishing pad 53, a supply unit 55 for supplying polishing liquid to the surface of the SiC substrate 51, and a heating device 1 for heating the surface of the SiC substrate 51 by irradiating it with microwaves.

[0059] The chuck table 52 may, for example, hold the SiC substrate 51 by suction. The chuck table 52 may also be connected to a driving means such as a motor and rotated by the driving means around a rotation axis extending in the vertical direction.

[0060] The polishing pad 53 is used to polish the SiC substrate 51, and may be disc-shaped, for example. The polishing pad 53 may be formed from a foamed rigid material such as foamed rigid polyurethane, or from a nonwoven fabric impregnated with urethane or the like. The polishing pad 53 may or may not contain abrasive particles such as silica. If the polishing pad 53 does not contain abrasive particles, it is preferable that the polishing liquid contains free abrasive particles.

[0061] The holding portion 54 may hold the polishing pad 53 by, for example, holding a base on which the polishing pad 53 is fixed to its lower surface. The holding portion 54 may rotate, for example, around a rotation axis extending in the vertical direction, or it may not. In the former case, the holding portion 54 may be connected to a driving means such as a motor and rotated around a rotation axis extending in the vertical direction by the driving means.

[0062] The supply unit 55 may, for example, supply polishing liquid stored in a tank to the upper surface of the SiC substrate 51 via a nozzle or the like. The supply unit 55 may, for example, supply the polishing liquid to the vicinity of the center of the SiC substrate 51, or to other locations. Known polishing liquids can be used.

[0063] The chuck table 52, polishing pad 53, holding unit 54, and supply unit 55 are already publicly known, and therefore their detailed descriptions are omitted.

[0064] The heating device 1 may, for example, heat the surface of the SiC substrate 51 from above. As an example, the microwave irradiation device 30 described in Embodiment 1 may be positioned such that the positive z-axis direction of the microwave irradiation device 30 is directed downward in the vertical direction. Furthermore, it is preferable that at least one of the longitudinal resistance value of the resistor 35 of the microwave irradiation device 30 and the power of the microwaves supplied to the microwave irradiation device 30 are designed so that the microwaves output from the microwave irradiation device 30 reach the surface of the SiC substrate 51 and heat that surface.

[0065] It is preferable that the surface of the SiC substrate 51 be heated to a temperature above room temperature by the heating device 1. This is to improve the efficiency of polishing. Also, since the polishing solution usually contains water, it is preferable that the surface of the SiC substrate 51 be heated to a temperature below the boiling point of water by the heating device 1. For example, the surface of the SiC substrate 51 may be heated to a temperature in the range of 25°C or higher and 80°C or lower.

[0066] Next, a method for polishing a SiC substrate according to this embodiment will be described. First, with the SiC substrate 51 held in the chuck table 52, the chuck table 52 is rotated, and polishing liquid is supplied to the surface of the SiC substrate 51 from the supply unit 54. Also, the polishing pad 53, held by the holding unit 54, is brought into contact with the surface of the SiC substrate 51. The holding unit 54 may be rotated as appropriate. Because the SiC substrate 51 is rotating, the SiC substrate 51 is polished by the polishing pad 53 contacting the surface. Furthermore, the efficiency of the polishing can be improved by heating the surface of the SiC substrate 51 with microwaves from the heating device 1 during the polishing process.

[0067] As described above, with the SiC substrate polishing apparatus 50 according to this embodiment, the surface of the SiC substrate 51 can be locally heated with microwaves in an open system by using the heating device 1. Since the SiC substrate 51 has a particularly high microwave absorption capacity, it can be heated efficiently with microwaves.

[0068] (Embodiment 3) A manufacturing apparatus and manufacturing method for retread tires according to Embodiment 3 of the present invention will be described with reference to the drawings. The manufacturing apparatus for retread tires according to this embodiment manufactures retread tires by performing vulcanization bonding using the heating apparatus according to Embodiment 1.

[0069] Conventionally, in the pre-cure method, a method for manufacturing retreaded tires, a vulcanized tread rubber with a tread pattern formed on it is attached to a base tire via unvulcanized rubber, and the unvulcanized rubber is heated to vulcanize and bond the base tire and the tread rubber. In the conventional pre-cure method, the entire base tire, tread rubber, and unvulcanized rubber are heated in a vulcanizing can to perform the vulcanization and bonding, which results in the entire base tire being heated during the vulcanization and bonding process, and this heating causes the base tire to deteriorate.

[0070] The retread tire manufacturing apparatus and manufacturing method according to this embodiment can provide a retread tire manufacturing apparatus and manufacturing method that can reduce the deterioration of the base tire during the manufacturing of retread tires.

[0071] Figure 14 is a schematic diagram showing the configuration of a retread tire manufacturing apparatus 60 according to this embodiment. The retread tire manufacturing apparatus 60 according to this embodiment includes a holding section 64 for holding a base tire 61, and a heating device 1 that heats the unvulcanized rubber 62 from the outer circumference side of the tread rubber 63, which is placed on the outer circumference of the base tire 61 via unvulcanized rubber 62, by irradiating the unvulcanized rubber 62 with microwaves, thereby vulcanizing and bonding the base tire 61 and the tread rubber 63. A roller 65 for pressing the tread rubber 63 onto the outer circumference of the base tire 61 may be further included as needed.

[0072] The holding portion 64 may, for example, have a wheel to which a base tire 61 is attached, and a support portion that supports the wheel. Also, for example, the base tire 61 attached to the wheel may be filled with air. Furthermore, the wheel may be rotatable in the holding portion 64. In this case, the holding portion 64 may be connected to a driving means such as a motor, and the wheel may be rotated around a rotation axis by the driving means.

[0073] The roller 65 may press the tread rubber 63, which is positioned on the outer surface of the unvulcanized rubber 62, toward the central axis side of the base tire 61.

[0074] The heating device 1 heats the rubber 62 from the outer periphery side of the tread rubber 63, which is placed on the outer circumferential surface of the base tire 61 via unvulcanized rubber 62. For example, the microwave irradiation device 30 described in Embodiment 1 may be positioned so that the positive z-axis direction of the microwave irradiation device 30 points toward the radial center of the base tire 61. Furthermore, it is preferable that at least one of the longitudinal resistance value of the resistor 35 of the microwave irradiation device 30 and the power of the microwaves supplied to the microwave irradiation device 30 be designed so that the microwaves output from the microwave irradiation device 30 reach the unvulcanized rubber 62 and can vulcanize and bond the base tire 61 and the tread rubber 63. In order to prevent deterioration of the base tire 61, it is preferable that the reach range in the z-axis direction of the microwaves output from the microwave irradiation device 30 be as short as possible within the range in which the base tire 61 and the tread rubber 63 can be vulcanized and bonded.

[0075] Preferably, the heating device 1 heats the unvulcanized rubber 62 to a temperature at which it can vulcanize and bond the base tire 61 and the tread rubber 63. The unvulcanized rubber 62 may be heated to a temperature within the range of 120°C to 200°C, for example.

[0076] Next, a method for manufacturing retreaded tires will be described. First, a base tire 61 is attached to a holding unit 64. Air may be filled into the base tire 61 attached to the holding unit 64. If a tread pattern remains on the outer surface of the base tire 61 at this point, the outer surface may be shaved down to a predetermined dimension. After that, vulcanized tread rubber 63 is placed on the outer surface of the base tire 61 held by the holding unit 64 via unvulcanized rubber 62. As an example, the placement of the tread rubber 63 may be done by attaching a thin strip of rubber 62 to the outer surface of the base tire 61, and then, while rotating the base tire 61 with the holding unit 64, attaching the strip of tread rubber 63 to the outer surface of the rubber 62. For example, rubber glue may be used to attach the unvulcanized rubber 62 and the tread rubber 63. When attaching the tread rubber 63 to the outer surface of the rubber 62, the tread rubber 63 may be pressed towards the rubber 62 by a roller 65 while rotating the base tire 61 with the holding unit 64. Alternatively, as shown in Figure 14, after the tread rubber 63 is attached to the rubber 62, the heating device 1 may be used to irradiate the unvulcanized rubber 62 with microwaves from the outer circumference of the tread rubber 63 to heat the rubber 62 and vulcanize and bond the base tire 61 and the tread rubber 63. The holding unit 64 may rotate the base tire 61 at a rotational speed that can properly achieve vulcanization bonding using microwaves irradiated from, for example, the microwave irradiation device 30. Once the tread rubber 63 is attached to the entire circumference of the rubber 62 and vulcanization bonding is performed by the heating device 1, the retreaded tire is completed.

[0077] In this embodiment, an example was described in which unvulcanized rubber 62 is first attached to the base tire 61, and then the tread rubber 63 is attached; however, this is not required. As another example, the unvulcanized rubber 62 and the tread rubber 63 may be attached to the outer surface of the base tire 61 simultaneously. In this case, for example, the tread rubber 63 with unvulcanized rubber 62 attached to one surface may be attached to the outer surface of the base tire 61.

[0078] Furthermore, in this embodiment, as an example, a case in which the unvulcanized rubber 62 is heated using the heating device 1 at one location in the circumferential direction of the base tire 61 has been described, but this is not required. As another example, a plurality of microwave irradiation devices 30 may be arranged on the outer circumference of the base tire 61 held by the holding part 64 so as to surround the base tire 61 all around. Then, by performing microwave heating with the plurality of microwave irradiation devices 30, the entire tread rubber 63, which is arranged on the outer surface of the base tire 61 via the unvulcanized rubber 62, may be vulcanized and bonded to the base tire 61 all at once. In this case, the time required to vulcanize and bond the base tire 61 and the tread rubber 63 can be shortened. Note that the plurality of microwave irradiation devices 30 may be supplied with microwaves generated by a single microwave generator 10, or microwaves generated by multiple microwave generators 10 may be supplied to each of them.

[0079] As described above, with the retread tire manufacturing apparatus 60 according to this embodiment, by using the heating device 1, the unvulcanized rubber 62 can be locally internally heated with microwaves in an open system.

[0080] The embodiments described above are illustrative examples for specifically carrying out the present invention and do not limit the technical scope of the invention. The technical scope of the invention is indicated by the claims rather than by the description of the embodiments, and modifications within the literal scope and equivalent meaning of the claims are intended.

[0081] 1 Heating device 10 Microwave generator 20 Coaxial cable 30 Microwave irradiation device 31 Inner lines 31b, 32b, 33b Tip 32 First outer line 33 Second outer line 34 Connecting line 35 Resistor 36 Substrate 50 SiC substrate polishing device 51 SiC substrate 52 Chuck table 53 Polishing pads 54, 64 Holding part 55 Supply part 60 Retread tire manufacturing device 61 Base tire 62 Unvulcanized rubber 63 Tread rubber

Claims

1. A microwave irradiation device for irradiating microwaves, comprising: an inner line; first and second outer lines arranged at intervals on both sides of the inner line; and a connecting line connecting the first and second tip ends of the first and second outer lines, which are the ends opposite to the microwave introduction side.

2. A microwave irradiation apparatus according to claim 1, further comprising one or more resistors connecting the inner line, the first and second outer lines, and the connecting line, to at least one of them.

3. A microwave irradiation apparatus according to claim 1 or 2, further comprising a dielectric substrate, wherein the inner line, the first and second outer lines, and the connecting line are each arranged on the substrate.

4. A microwave irradiation device according to any one of claims 1 to 3, wherein the inner line and the microwave introduction ends of the first and second outer lines are each connected to a coaxial cable, and the line width and height of the inner line, and the distance between the inner line and the first and second outer lines are determined so as to match the impedance between the microwave irradiation device and the coaxial cable.

5. A microwave irradiation device according to any one of claims 1 to 4, a microwave generator for generating microwaves, and a transmission line for transmitting the microwaves generated by the microwave generator to the inner line of the microwave irradiation device and to the microwave introduction end of the first and second outer lines, respectively, and configured to heat an object to be heated by irradiating it with microwaves from the microwave irradiation device.

6. A semiconductor wafer polishing apparatus comprising: a chuck table that can hold and rotate a semiconductor wafer; a polishing pad for polishing the surface of the semiconductor wafer; a holding unit for holding the polishing pad; a supply unit for supplying polishing liquid to the surface; and a heating device according to claim 5 for heating the surface by irradiating it with microwaves.

7. A retread tire manufacturing apparatus comprising a holding part for holding a base tire, and a heating device according to claim 5, which heats the unvulcanized rubber by irradiating it with microwaves from the outer circumference side of the tread rubber, which is placed on the outer circumference surface of the base tire via unvulcanized rubber, thereby vulcanizing and bonding the base tire and the tread rubber.

8. A method for heating an object to be heated, comprising the steps of supplying microwaves to the inner line, the first and second outer lines, and the microwave introduction side ends of the first and second outer lines, in a microwave irradiation device comprising an inner line, first and second outer lines arranged at intervals on both sides of the inner line, and connecting lines connecting the first and second tip ends of the first and second outer lines, which are the ends opposite to the microwave introduction side; and irradiating the object to be heated with microwaves from the microwave irradiation device.

9. The heating method according to claim 8, wherein the object to be heated is a semiconductor wafer.

10. A manufacturing method for manufacturing a semiconductor device using a semiconductor wafer, comprising the step of heating the semiconductor wafer by the heating method described in claim 8.

11. A method for polishing a semiconductor wafer, comprising the steps of: rotating a chuck table holding the semiconductor wafer; supplying a polishing solution to the surface of the semiconductor wafer; polishing the surface by bringing a polishing pad into contact with the surface; and heating the surface by irradiating it with microwaves from the heating device described in claim 5.

12. A method for manufacturing a retread tire, comprising the steps of: placing tread rubber on the outer surface of a base tire via unvulcanized rubber; and heating the unvulcanized rubber from the outer surface of the tread rubber by irradiating it with microwaves using the heating device described in claim 5, thereby vulcanizing and bonding the base tire and the tread rubber.

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