JP5616271B2 - Induction heating device and magnetic pole - Google Patents

Description

  The present invention relates to an induction heating apparatus, and more particularly to an induction heating apparatus suitable for controlling the temperature of an object to be heated and a magnetic pole used in the induction heating apparatus when heat treating a large-diameter semiconductor substrate.

  When batch processing a large-sized semiconductor substrate, even if a metal film or the like is formed on the substrate surface, the metal film is directly heated, resulting in variations in temperature distribution in the substrate surface. There is known an induction heating apparatus capable of suppressing the above (for example, see Patent Document 1).

  The technique disclosed in Patent Document 1 includes a chamber constituting a process chamber and an induction heating coil wound around a core constituting a magnetic pole. According to the induction heating apparatus having such a configuration, the magnetic flux generated through the magnetic pole is generated in parallel with the mounting direction of the semiconductor substrate that is the object to be heated disposed in the chamber. For this reason, even when a metal film or the like is formed on the surface of the semiconductor substrate, magnetic flux is not input in a direction intersecting with the metal film, and the substrate may be directly heated by induction heating. No. For this reason, the temperature distribution in the substrate surface does not vary.

JP 2010-59490 A

  According to the induction heating apparatus configured as disclosed in Patent Document 1, the metal film is certainly directly heated by induction heating even in a semiconductor substrate or the like whose surface is coated with the metal film. There is no fear.

  However, in the induction heating apparatus configured as described above, the magnetic pole end face is made of an induction heating member in order to produce a characteristic action of generating an alternating magnetic flux from the induction heating coil in parallel with the mounting direction of the semiconductor substrate. It is necessary to arrange the susceptor so as to face and be close to the end face. For this reason, problems specific to the device include a thermal problem with respect to the magnetic pole and the opposed end face of the induction heating coil, and an influence of interlinkage magnetic flux on the opposed end face of the induction heating coil.

  For example, as a thermal problem, ferrite is generally used for the magnetic pole. Since the Curie point temperature of a general ferrite core is about 100 ° C. to about 460 ° C., if the heating temperature of the susceptor rises to about 1000 ° C., the magnetic pole may exceed the Curie point due to the influence of radiant heat. is there. When the Curie point is exceeded, the residual magnetic flux density as a magnet becomes 0, so that it cannot be used as a magnetic pole. Also, regarding the induction heating coil, when the temperature rises remarkably, there is a possibility that it cannot be used.

  Further, the influence of the interlinkage magnetic flux is an event in which the induction heating coil itself is induction-heated due to the magnetic flux leaking from the magnetic pole or the influence of the reaching magnetic flux from the adjacent induction heating coil. When such an event occurs, there is a problem that power loss increases.

  Therefore, in the present invention, in the induction heating apparatus provided with the induction heating coil that forms an AC magnetic flux in a direction parallel to the surface of the object to be heated in the induction heating member, while suppressing the heat generation of the magnetic pole and the induction heating coil, An induction heating apparatus and a magnetic pole that can reduce loss are provided.

In order to achieve the above object, an induction heating apparatus according to the present invention includes an induction heating member disposed in a chamber, and the induction heating member is disposed outside the chamber via an opening formed in the chamber. An induction heating coil wound around a magnetic pole disposed with its end faces facing each other, and generating an alternating magnetic flux toward the end face of the induction heating member, the induction heating member and the magnetic pole A magnetically permeable shielding plate that separates the inner region and the outer region of the chamber, and a cooling pipe through which a refrigerant can be inserted while being stacked and disposed so as to be in close proximity to or close to the magnetically permeable shielding plate A cooling plate that is closely arranged to prevent overheating of the magnetic pole, and the induction heating coil includes a conductor through which a refrigerant for cooling the magnetic pole can be inserted , and a litz wire that is a conductor through which the refrigerant does not pass. Combination Constituted by causing, characterized in that the can be inserted conductor the refrigerant is arranged on the object induction heating member proximally.

  In the induction heating apparatus having the above-described features, the induction heating coil and the magnetic pole are preferably brought into close contact with each other. By setting it as such a structure, the cooling effect of a magnetic pole can be improved.

  In the induction heating apparatus having the above-described characteristics, a member for improving heat conduction may be interposed between the induction heating coil and the magnetic pole. With such a configuration, the magnetic pole can be cooled efficiently and evenly.

  The induction heating apparatus having the above-described characteristics may include a filling member that integrates the induction heating coil and the magnetic pole as components. Even in such a configuration, the magnetic pole can be cooled efficiently and evenly.

  Furthermore, the induction heating apparatus having the above-described features includes a plurality of the magnetic poles and a yoke connecting the plurality of magnetic poles, and the end surfaces of the magnetic poles are arranged to face the induction heating member, It is desirable to provide the induction heating coil in the vicinity of the end face of the magnetic pole. With such a configuration, the flux linkage can be reduced.

  According to the induction heating device having the characteristics as described above, in the induction heating device including the induction heating coil that forms an alternating magnetic flux in a direction parallel to the surface of the object to be heated in the induction heating member, It is possible to reduce power loss while suppressing heat generation.

It is a top view which shows the structure of the induction heating apparatus which concerns on 1st Embodiment. It is a figure which shows the structure of the AA cross section in FIG. It is a top view which shows the relationship between the angle of two magnetic poles, and an opening part. It is a figure which shows the front form of the opening part provided in the housing. It is a figure which shows the detail of the assembly | attachment form of the magnetic-permeable shielding member and cooling plate provided in the opening part. It is side surface sectional drawing which shows the tubular member which comprises an induction heating coil, and the arrangement | positioning form of a litz wire. It is a top view for demonstrating the form of the opening part provided in the housing in the induction heating apparatus which concerns on 2nd Embodiment. It is a figure which shows the front form of the opening part provided in the housing in the induction heating apparatus which concerns on 2nd Embodiment.

  Hereinafter, embodiments of the induction heating apparatus of the present invention will be described in detail with reference to the drawings. First, a schematic configuration of the induction heating apparatus according to the first embodiment will be described with reference to FIGS. 1 and 2. FIG. 1 is a partial cross-sectional block diagram illustrating a planar configuration of the induction heating apparatus, and FIG. 2 is a block diagram illustrating a cross-section taken along line AA in FIG.

The induction heating apparatus 10 according to the present embodiment is a batch-type apparatus in which a wafer 60 as a heated object and a susceptor 16 as an induction heating member (heating element) are stacked in multiple stages to perform heat treatment.
The induction heating apparatus 10 is configured based on a chamber 12, an excitation unit 28 disposed outside the chamber 12, and a power supply unit 40.

  The chamber 12 is a process chamber configured based on the boat 14, the rotary table 18, and the housing 26. The boat 14 is configured by stacking a plurality of susceptors 16 on which wafers 60 to be heated are placed in a vertical direction. A support member (not shown) is disposed between the susceptors 16 and is configured to maintain a predetermined interval for disposing the wafer 60. The support member (not shown) is not affected by the magnetic flux, is preferably made of a member having high heat resistance and a low coefficient of thermal expansion, and specifically, made of quartz or the like.

The susceptor 16 may be made of a conductive member, and may be made of, for example, graphite, SiC, SiC-coated graphite, refractory metal, or the like.
The rotary table 18 is configured based on a table 20, a rotary shaft 22, and a base 24. The table 20 is a table for supporting the boat 14 composed of a plurality of susceptors 16 arranged in a stacked manner, and a support portion (not shown) is provided. The rotating shaft 22 is a shaft fixed to the rotation center of the table 20, and rotates by receiving a driving force from a driving source (not shown), thereby rotating the table 20, and a plurality of susceptors mounted on the table 20. 16 is rotated. The base 24 is a base having a drive source such as a motor for rotating the rotary shaft 22, and ensures a stable state of the table 20. By rotating the boat 14 by the rotary table 18, the susceptor 16 can be uniformly heated even when the excitation unit 28, which is a heating source, is arranged biased with respect to the induction heating device 10. Further, by arranging the excitation unit 28 in a biased manner, it is possible to reduce the size of the device as compared with the case where the induction heating device 10 is evenly arranged on the outer periphery of the boat 14 (chamber 12).

  The housing 26 is a partition for keeping the inside of the chamber 12 in a vacuum. The housing 26 in the embodiment can be formed easily by forming the planar form into a polygon (hexagon in the example shown in FIG. 1). The component of the housing 26 is made of aluminum or stainless steel from the process side. Here, aluminum has a disadvantage in shape formation and a welding surface for shape formation, and has lower heat resistance than stainless steel. For this reason, stainless steel is often used as a constituent member of the housing 26. As shown in FIGS. 3 to 5, an opening 42 is provided in at least a part of the housing 26, and a magnetically permeable shielding plate 46 and a magnetically permeable cooling plate 48 are in close contact with or in the opening 42. Laminated and arranged so as to be close to each other. The magnetically permeable shielding plate 46 is a member for separating the inner region and the outer region of the chamber 12 and has vacuum strength, magnetic flux permeability, heat resistance, low thermal expansion, low thermal conductivity, and thermal shock resistance. For example, quartz may be used. On the other hand, the cooling plate 48 cools the magnetically permeable shielding plate 46 by conducting the temperature of the refrigerant transmitted from the cooling pipe 50, which will be described in detail later, and the magnetic pole 32 (32 a associated with the heating of the magnetically permeable shielding plate 46. 32c) and 34 (34a to 34c) to be cooled to play a role of preventing overheating. Examples of the constituent member of the cooling plate 48 include ceramic members such as aluminum nitride, SiC, and alumina.

  In the housing 26 according to the embodiment, openings 42 are provided on two sides forming a planar hexagonal body. Further, in the case of the example according to the embodiment, a square piece 26a constituting the diaphragm portion 44 that partially narrows the opening area of the opening portion 42 is provided at the apex portion of the hexagon. As a result, the opening 42 is constituted by two divided openings 42 a that are communicated with each other via the diaphragm 44 over two adjacent sides.

  The magnetically permeable shielding plate 46 according to the embodiment is pressed and held by a step portion 26b provided on the outer edge of the opening 42 of the housing 26 made of aluminum or the like. A cooling plate 48 is closely arranged outside the magnetically permeable shielding plate 46 (between the magnetically permeable shielding plate 46 and the magnetic poles 32 and 34), and cooling that allows a refrigerant to be inserted into the outer edge portion of the cooling plate 48. The tube 50 is closely placed. With such an arrangement configuration, heat exchange is performed between the refrigerant inserted into the cooling pipe 50 and the cooling plate 48 to cool the cooling plate 48. Since the cooling plate 48 has higher thermal conductivity than the magnetically permeable shielding plate 46, the heat exchange (heat transfer) between the magnetically permeable shielding plate 46 and the cooling plate 48 is performed before or after the heat exchange. During the process, the entire cooling plate 48 is cooled. Thereafter, heat exchange is performed between the cooled cooling plate 48 and the magnetically permeable shielding plate 46, and the magnetically permeable shielding plate 46 is cooled. Thereby, it can avoid that a magnetic pole is overheated by the influence of radiant heat.

  The magnetically permeable shielding plate 46 is pressed against the stepped portion 26b through the O-ring 52 as shown in FIG. And the cooling plate 48 and the cooling pipe 50 are arrange | positioned. With such a configuration, the inner region and the outer region of the chamber 12 can be isolated, and the inside of the chamber 12 can be evacuated.

  The exciting unit 28 includes a core 30 (30a to 30c) and induction heating coils 36 (36a to 36c) and 38 (38a to 38c). The core 30 is an iron core formed in a bowl shape. The core 30 has magnetic poles 32 (32a to 32c) and 34 (34a to 34c) formed by winding induction heating coils 36 and 38, which will be described in detail later, at both ends, and connects between the two magnetic poles. Yoke 35 (35a to 35c) is provided. The end faces of the magnetic poles 32 and 34 are configured to have a plane parallel to the tangent line of the circular susceptor 16, that is, a plane orthogonal to the radial extension line of the susceptor 16. With this configuration, the end surfaces of the magnetic poles 32 and 34 can be opposed to the side surfaces of the susceptor 16, and the induction heating coils 36 and 38 can be wound near the end surfaces of the magnetic poles 32 and 34. The leakage of magnetic flux from can be suppressed. Therefore, there is no waste in the magnetic flux input to the susceptor 16, and the heating efficiency can be improved. The core 30 is preferably composed of ferrite or the like. According to such a configuration, the magnetic poles 32 and 34 and the yoke 35 having desired shapes can be obtained by firing after forming a clay-like raw material. For this reason, shape formation can be performed freely.

  The induction heating coils 36 and 38 are conductive wires wound around both ends of the core 30 constituting the magnetic poles 32 and 34. By supplying current to the induction heating coils 36 and 38, magnetic flux is generated from the tip of the magnetic pole located in the direction intersecting with the winding direction of the coil. In the present embodiment, the magnetic pole end face (magnetic pole tip) faces in the direction orthogonal to the wafer placement surface of the susceptor 16, so that an alternating magnetic flux is generated from the magnetic pole end face in a direction parallel to the wafer placement face of the susceptor 16. Will be. As shown in FIG. 6, the induction heating coils 36 and 38 according to the embodiment include a conductor (tubular member: for example, a copper tube when water is used as the coolant) 36 a 1 (36 b 1, 36 c 1) that can be inserted with a coolant. It is configured by combining the litz wire 36a2 (36b2, 36c2) which is a conductor that does not allow the refrigerant to pass. Specifically, a tubular member is used for the tip of the magnetic pole 32a (32b, 32c) and the portion close to the tip of the magnetic pole 32a (for example, about one turn of the coil or two turns of the coil from the tip of the magnetic pole). In addition, a litz wire is used on the rear end side. Here, as for the winding form of the tubular member 36a1 and the litz wire 36a2, as shown in FIG. 6, a terminal may be provided on each of the tubular member 36a1 and the litz wire 36a2. At this time, the tubular member 36a1 and the litz wire 36a2 may be connected to the power supply unit 40 in series or in parallel.

  In FIG. 6, the tubular member 36a1 and the litz wire 36a2 are shown as separate members. However, the tubular member 36a1 and the litz wire 36a2 are integrated with an insulating filling member such as an epoxy resin to form a single component. It is also good. Moreover, although the litz wire was mentioned as an example as a conductor which does not let a refrigerant | coolant pass, a solid member may be sufficient.

  In the heating method in which the magnetic flux is generated in the horizontal direction with respect to the wafer mounting surface of the susceptor 16, the frequency of the current applied to the induction heating coils 36 and 38 is several tens of kHz. When copper is used for the tubular member, the copper tube (tubular member 36a1) having a thickness of about 1 mm is induction-heated, so that the heating efficiency of the susceptor 16 is reduced and the power loss is increased. On the other hand, if the litz wire 36a2 is formed by twisting together a plurality of strands (strips) of about 0.18φ, it is considered that the magnetic flux is transmitted. Due to the large amount of magnetic flux, induction heating occurs. When the Litz wire 36a2 that does not have a cooling action generates heat due to induction heating, the temperature rises and may exceed the operating temperature limit. For this reason, by arranging the tubular member 36a1 having a cooling action on the magnetic pole front end side and the litz wire 36a2 on the rear end side, it becomes possible to suppress power loss and prevent overheating of the coil. .

  The induction heating coils 36 and 38 according to the embodiment are wound so as to be in close contact with the magnetic poles 32 and 34. This is because by adopting such a configuration, the effect of preventing the heating of the magnetic pole tip by the cooling effect of the tubular member can be enhanced.

  An insulating heat equalizing member having a relatively high thermal conductivity such as an epoxy resin may be interposed between the magnetic poles 32 and 34 and the induction heating coils 36 and 38. With this configuration, the magnetic pole can be cooled efficiently and evenly. Further, a filling member having a relatively high thermal conductivity such as an epoxy resin may be filled between the induction heating coils 36 and 38 and the magnetic poles 32 and 34, and both may be integrated as components. .

The exciting unit 28 is configured by arranging a plurality (three in the example shown in FIG. 2) of the core 30 and the induction heating coils 36 and 38 configured as described above along the stacking direction of the susceptor 16.
Further, in the exciting unit 28 as described above, the core 30 of the embodiment has a predetermined angle θ formed by a line extending from the center point O of the susceptor 16 toward the center of each magnetic pole end face as shown in FIG. It is configured to have an angle (depending on the angle formed by the housing 26). By making the angle between the magnetic poles 32 and 34 and reversing the polarities of one magnetic pole 32 and the other magnetic pole 34, the generated magnetic flux travels between the magnetic poles 32 and 34. Thereby, it is possible to generate a magnetic flux passing through the center side of the susceptor 16 rather than a magnetic flux generated by the single magnetic pole 32 (34).

  The power supply unit 40 includes an inverter (not shown) corresponding to the induction heating coils 36 and 38 wound around the magnetic poles 32 and 34 of each core 30, an AC power supply (not shown), and a power control (not shown). The current and voltage to be supplied, the frequency, the frequency, and the like can be adjusted in units of induction heating coils 36 and 38 provided in each core 30. In the induction heating device 10 according to the embodiment, the induction heating coils 36 and 38 wound around the single core 30 (for example, the induction heating coil 36a wound around the magnetic pole 32a and the induction heating coil wound around the magnetic pole 34a). 38a) is a parallel or serial relationship on the circuit, and the winding direction is the same, and the current input direction is reversed. Thereby, the polarities of the two magnetic poles (for example, the magnetic pole 32a and the magnetic pole 34a) in each core 30 can be reversed. Here, when a resonant type inverter is adopted, a resonant capacitor matched to each control frequency is connected in parallel so that the frequency can be easily switched, and this is used as a signal from the power control unit. It is desirable to configure so that it can be switched accordingly.

  The power control unit according to the embodiment includes zone control means (not shown). The zone control means plays a role of controlling the input power to each induction heating coil 36, 38 while avoiding the influence of mutual induction occurring between the induction heating coils 36, 38 wound around the adjacent core 30. Bear.

  Since each of the induction heating coils 36 and 38 wound around the core 30 stacked in close proximity as described above is operated as an individual induction heating coil, the induction heating coils adjacent to each other vertically (for example, induction Mutual induction occurs in the heating coil 38a and the induction heating coil 38b), which may adversely affect individual power control. For this reason, the zone control means matches the frequency of the current applied to the adjacent induction heating coil based on the detected current frequency and waveform (current waveform) and synchronizes the phase of the current waveform (phase difference). Power control (zone control control) that avoids the influence of mutual induction between adjacently arranged induction heating coils by controlling so that the phase difference is approximated to 0 or a phase difference of 0) It is possible.

  Such control detects a current value, a current frequency, a voltage value, and the like supplied to the induction heating coils 36 and 38, and inputs them to the zone control means. In the zone control means, for example, the phase of the current waveform between the induction heating coils 36a, 38a wound around the core 30a and the induction heating coils 36b, 38b wound around the core 30b is detected, respectively, and this is synchronized or predetermined. Control to maintain the phase difference of. Such control is performed by outputting a signal that instantaneously changes the frequency of the current supplied to each induction heating coil to the power control unit.

  In the case of a configuration such as the induction heating apparatus 10 according to the present embodiment, the power control is based on a control map (vertical temperature distribution control map) stored in a storage unit (memory) (not shown) provided in the power control unit. Thus, it suffices to output a signal for outputting input power to be changed in units of elapsed time from the start of heat treatment. The control map corrects the temperature change between the stacked susceptors from the start of heat treatment to the end of heat treatment, and gives power to each induction heating coil to obtain an arbitrary temperature distribution (for example, uniform temperature distribution). Any value may be recorded as long as the elapsed time from the start of the heat treatment is recorded. Further, in the case where measurement means (not shown) for measuring the temperature of the susceptor 16 is provided, it is preferable to perform temperature control (power control) by feeding back the susceptor temperature in each zone.

  In the power supply unit 40 having such a configuration, the frequency of the current input to each induction heating coil 36 and 38 is instantaneously adjusted based on the signal from the power control unit, and the phase control of the current waveform is performed. By performing power control for each induction heating coil 36, 38, the temperature distribution in the vertical direction in the boat 14 can be controlled.

  Moreover, according to the induction heating apparatus 10 having such a configuration, since the magnetic flux works horizontally with respect to the wafer 60, even when a conductive member such as a metal film is formed on the surface of the wafer 60, There is no possibility that the temperature distribution of the wafer 60 is disturbed.

  According to the induction heating device having such a configuration, it is possible to efficiently heat the susceptor 16 that is an induction heating member while preventing the magnetic poles 32 and 34 disposed outside the chamber 12 from being heated.

  Next, a second embodiment according to the induction heating device of the present invention will be described in detail with reference to the drawings. Most configurations of the induction heating apparatus according to the present embodiment are the same as those of the induction heating apparatus 10 according to the first embodiment described above. Therefore, in the present embodiment, only the main parts that are different in configuration from the induction heating apparatus 10 according to the first embodiment are illustrated and described, and the same configuration is the same in the drawings. A detailed description is omitted with reference numerals. The difference from the induction heating apparatus 10 according to the first embodiment is the form of the opening 142 provided in the housing 26. Specifically, the opening 42 in the first embodiment is provided with an opening 42 on each of two sides of the housing 26 having a polygonal shape (hexagonal in the example shown in FIG. 1). The magnetically permeable shielding plate 46 and the cooling plate 48 are individually arranged for each. On the other hand, in the induction heating apparatus according to this embodiment, as shown in FIGS. 7 and 8, the housing 26 is not interposed in the opening 142, and a single magnetically permeable shielding plate 46 and a single cooling plate 48 are used. Thus, the opening 42 is shielded.

  Even in such a configuration, the induction heating coil is composed of a tubular member and a litz wire, so that the induction heating coil is prevented from being overheated, and the heating control with good heating efficiency is performed. It can be carried out.

  Moreover, in the said embodiment, although it showed that the terminal connected to the power supply part 40 was provided in each of the tubular member 36a1 and the litz wire 36a2 which comprise the induction heating coil 36, insertion of the refrigerant | coolant with respect to the tubular member 36a1 is possible. If so, the tubular member 36a1 and the litz wire 36a2 may be directly connected, and one terminal may be provided for each of the tubular member 36a1 and the litz wire 36a2.

DESCRIPTION OF SYMBOLS 10 ......... Induction heating apparatus, 12 ......... Chamber, 14 ......... Boat, 16 ......... Susceptor, 18 ......... Rotary table, 20 ......... Table, 22 ......... Rotating shaft, 24 ......... Base, 26 ......... Housing, 28 ......... Excitation part, 30 (30a-30c) ......... Core, 32 (32a-32c) ......... Magnetic pole, 34 (34a-34c) ......... Magnetic pole, 35 ( 35a-35c) ......... Yoke, 36 (36a-36c) ......... Induction heating coil, 38 (38a-38c) ......... Induction heating coil, 40 ......... Power supply, 42 ......... Opening, 46 ..... Magnetically permeable shielding plate, 48 .... Cooling plate, 50 .... Cooling tube, 60 ..... Wafer.

Claims (5)

An induction heating member is disposed in the chamber, and induction heating is performed on the outside of the chamber around a magnetic pole disposed with an end face facing the induction heating member through an opening formed in the chamber. An induction heating device having a coil and generating an alternating magnetic flux directed to an end face of the induction heating member,
Between the induction heating member and the magnetic pole, a magnetically permeable shielding plate that separates an inner region and an outer region of the chamber, and a laminated arrangement so as to be in close proximity to or close to the magnetically permeable shielding plate, A cooling plate disposed in close contact with a cooling pipe through which a refrigerant can be inserted to prevent overheating of the magnetic pole;
The induction heating coil is configured by combining a conductor through which a refrigerant for cooling the magnetic pole can be inserted and a litz wire that is a conductor through which the refrigerant does not pass, and the conductor through which the refrigerant can be inserted is guided. An induction heating apparatus, which is disposed near the heating member .   The induction heating apparatus according to claim 1, wherein the induction heating coil and the magnetic pole are brought into close contact with each other.   The induction heating apparatus according to claim 1, wherein a member for improving heat conduction is interposed between the induction heating coil and the magnetic pole.   The induction heating apparatus according to claim 1, further comprising a filling member that integrates the induction heating coil and the magnetic pole as components. A plurality of the magnetic poles, and a yoke connecting the magnetic poles,
The induction heating according to any one of claims 1 to 4, wherein an end face of each magnetic pole is arranged to face the induction heating member, and the induction heating coil is provided in the vicinity of the end face of the magnetic pole. apparatus.

Images