JP4566610B2 - Ceramic plate heating element - Google Patents

Description

  The present invention relates to a thin ceramic plate-like heating element capable of rapidly heating a tape-like object to be heated to a high temperature, and in particular, a predetermined temperature control is performed over the entire heating region of the tape-like object to be continuously supplied. The present invention relates to a ceramic plate-like heating element that can be performed strictly and has high heating efficiency and low power consumption.

Conventionally, when a thin film is continuously formed on an object to be heated (substrate) in a tape shape by using an MOCVD apparatus or the like, as shown in FIG. 4, a metal heating element is covered with glass fibers around the quartz tube 20. An external heating method has been adopted in which a desired thin film is formed by heating the mantle heater 24 and passing a tape 21 as a heated body through the quartz tube 20. Reference numeral 22 denotes an apparatus for supplying a thin film forming substance.
However, when such a metal heater is used and the external heating method is used, the output is insufficient for rapid heating to a high temperature, and the temperature control in the quartz tube 20 has a poor response, and strict temperature control cannot be performed. was there. In addition, the external heating method has a drawback that it is difficult to increase the size (large diameter), and one heating device is required for each tape to be processed, resulting in poor productivity.

For this reason, it has been considered to heat by an internal heating method using a ceramic heater that can be heated to a higher temperature. In general, since a ceramic heater is difficult to process, it is common to finish it into a round bar-shaped heating element and heat it by energizing it.
However, in order to aim at high speed, high temperature, and uniform heating, it is necessary to arrange linear linear rod heating elements closely, or to repeatedly bend the rods repeatedly to form a multi-shank. However, the former has a problem that a large number of terminal portions necessary for power feeding are required for each linear rod-shaped heating element, and in the latter, repeated dense bending becomes a limit at a pitch of about 20 mm. (For example, refer to Patent Document 1).
Japanese Patent Laid-Open No. 7-18445

For this reason, it is conceivable to use a ceramic plate heater (heater). Since the plate-like heating body can be heated in a planar shape toward the body to be heated, there is an advantage that the heating efficiency is the highest, the uniform heating area is widened, and the power consumption is reduced.
However, in the conventional plate-like heating element, uniform heating is easy in the heating zone, but the terminal portion is thicker than the plate thickness of the heating portion, or a large R is required to bend the terminal portion into an L shape. In addition, in order to avoid contact between the terminals of adjacent heating elements, it is necessary to widen the intervals between the heating elements, so that unless the device is specially devised, the temperature drops between the heating elements arranged in tandem. There is.
In particular, when heating a tape or the like, when a heating device is configured by arranging a plurality of plate-like heating elements in the longitudinal direction, a temperature drop occurs between the heating elements arranged in tandem, or there is an uncontrollable region. Existence was a serious obstacle. In recent years when advanced thin film characteristics and annealing characteristics have been demanded, the demand from the viewpoint of uniform heating has become stronger.

 The present invention makes it possible to precisely perform a predetermined temperature control over the entire heating region of a thin ceramic plate-like heating element, particularly a tape-like heating object, capable of rapidly heating the tape-like heating object to a high temperature. In addition, a ceramic plate-like heating element that has high heating efficiency and can be used for low power consumption is provided.

  In order to solve the above-mentioned problems, the present inventors have conducted intensive research. As a result, a thin plate-shaped heating element is used, and slits and cutout spaces are formed therein, so that a plurality of plate-shaped heating elements are formed. It was found that the width of the temperature drop zone between the heating elements adjacent in the longitudinal direction can be made as small as possible by improving the arrangement structure.

 Based on this knowledge, the present invention is made of 1) ceramics in which a plurality of plate-like heating elements having L-shaped power supply terminal portions at both ends are arranged on one side of a tape-like object to be heated in the longitudinal direction of the object to be heated. It is a plate-like heating element, and by forming a plurality of slits alternately in the width direction of the plate-like heating element, it is U-shaped when viewed from the plane of the plate-like heating element in almost the entire area of the center of the plate-like heating element. Alternatively, an M-shaped heat generating portion having a narrow U shape with a continuous U-shape is provided, and at least one of the L-shaped terminal portions of the adjacent plate-shaped heat generating elements is arranged so as to cross each other without contact. 2) A ceramic plate-like heating element, and 2) R of the plate-like heating element bent in an L shape in a direction away from the tape-like object to be heated is 10 mm or less. The ceramic plate-like heating element according to 1 above, 3) of the terminal part of the plate-like heating element 4. The ceramic plate-like heating element according to 1 or 2 above, wherein the thickness is equal to or less than the thickness of the heating part, 4) portions of the plate-like heating element intersecting each other without contact The ceramic plate-like heating element according to any one of 1 to 3 above, wherein a plurality of voids are provided in the longitudinal direction of the object to be heated. The ceramic plate-like heating element according to any one of the above 1 to 4, wherein the plurality of plate-like heating elements are arranged in tandem with the same width.

Further, the present invention is characterized in that 6) the outer edges of the plate-like heating elements at the crossing portions provided with the notches are aligned with the outer edges of the plurality of arranged plate-like heating elements. 7) The plate-like heating element made of ceramics according to any one of 1 to 5 above, and 7) the width of the intersecting portion of the plate-like heating elements provided with a notch space is ± the plate width of the heating part. The ceramic plate-like heating element according to any one of 1 to 6 above, wherein the plate-like heating element has a thickness of 1 to 5 mm and is arranged in the longitudinal direction. The ceramic plate-like heating element according to any one of 1 to 7 above, wherein the total plate width is 10 to 40 mm and the clearance of the slit is 10 mm or less, 9) the plate width of the heating part is 3 to 20 mm The ceramic plate according to any one of 1 to 8 above, which is Heating elements, 10) A plurality of tape-shaped heated bodies move continuously or intermittently, and plate-like heating elements are arranged in a plurality of rows and columns along the longitudinal direction of the heated bodies. The ceramic plate-like heating element according to any one of 1 to 9 above, 11) The plate-like heating element is made of MoSi ₂ type, SiC type or lanthanum chromite type ceramics. The ceramic plate-like heating element according to any one of the above, 12) the plate-like heating element is made of high-purity MoSi ₂ or SiC ceramics, and the contents of impurities Fe, Ni, and Cr contained in the ceramics are respectively The ceramic plate-like heating element according to any one of 1 to 11 above, wherein the content is 200 ppm or less and the contents of Na and K are each 20 wtppm or less.

 The present invention makes it possible to precisely perform a predetermined temperature control over the entire heating region of a thin ceramic plate-like heating element, particularly a tape-like heating object, capable of rapidly heating the tape-like heating object to a high temperature. In addition, there is a remarkable effect that it is possible to provide a ceramic plate-like heating element that has good heating efficiency and can cope with low power consumption.

Next, the present invention will be specifically described mainly based on the drawings. However, the structure shown in the figure is merely an example for explaining the present invention so that the present invention can be easily understood, and is not limited to the structure shown in the figure. That is, modifications and other structures or configurations based on the technical idea of the present invention are naturally included in the present invention.
Plate-like heating element of the present invention, the terminal portion of the power supply to the opposite ends (electrodes and terminals) provided, which generates heat by passing a current, the material of the heat generating element, MoSi ₂ system, SiC system or A plate-like heating element made of ceramics such as lanthanum chromite ceramics can be used.
In particular, a heating element containing MoSi ₂ as a main component (containing 70 wt% or more of MoSi ₂ ) has excellent oxidation resistance and can be used in the atmosphere or an oxidizing atmosphere. It is a desirable material because it is resistant to thermal shock and can generate heat to an extremely high temperature in a short time. In addition, rapid temperature rise to the processing temperature has an advantage that the processing speed is increased, the production speed is increased, and the cost can be reduced.

In addition, when a high-purity MoSi ₂ or high-purity SiC heating element is used, there is no emission of contaminants from the heating element, and there is no deterioration or deterioration of characteristics due to contamination of the film-formed or heat-treated material. It is a preferred material because it is not present.
FIG. 1 is a partial explanatory view when two ceramic plate-like heating elements of the present invention are combined. As shown in FIG. 1, in the ceramic plate-like heating element 1 of the present invention, the width of the power supply terminal portion 2 corresponds to the width of the entire plate-like heating element. That is, a plurality of plate-like heating elements 1 are designed to be aligned along the longitudinal direction of the tape-shaped heated body 3 on one side of the heated body (tape) 3, that is, on the lower side in FIG.

A plurality of slits 4 are alternately formed in the width direction of the ceramic plate-like heating element 1. As a result, a heat generating part 5 having a narrow width and an M shape in which the U-shape or the U-shape is continuous as viewed from the plane of the plate-like heating element can be formed in almost the entire center of the plate-like heating element.
At this time, if the width of the heat generating portion is reduced to about 1/4 of the width of the terminal portion, even if the thickness of the terminal portion is the same as that of the heat generating portion, resistance heating at the terminal portion is suppressed, and the temperature of the electrode portion 11 to be fed is suppressed. Can be lowered sufficiently. When the terminal part including the electrode part 11 is thin, there is an advantage that the heating elements can be brought closer to each other.
This ceramic plate-like heating element 1 can cut and process a heating part or a terminal part into an arbitrary shape by processing means such as punching, electric discharge machining, and laser processing.
Here, the important point of the present invention is that the L-shaped terminal portion of the adjacent plate-like heating element 1 and the heat generating portion 6 in the vicinity of the terminal portion intersect each other without contact. As a result, the plurality of plate-like heating elements 1 are arranged close to each other, and the region where no heat generating portion is present can be remarkably reduced, and uniform heating can be achieved over the entire length.

In order to cross the heat generating parts 6 in the vicinity of the terminal part without contacting each other, as shown in FIG. 1, it can be obtained by providing a space 7 that is cut out mutually inside the crossing direction. The voids are usually rectangular because they are easy to manufacture, but other shapes may be used as long as they can cross each other without contacting the heat generating portion 6.
In this case, the outer edge portion 8 of the heat generating portion 6 at the intersecting portion provided with the voids 7 cut out from each other is aligned with the other outer edge portions 9 of the plurality of aligned plate-like heat generating elements. It will be necessary. The width of the heat generating portion 6 at the intersecting portion is preferably within ± 20% of the plate width of the heat generating portion 5. As a result, the heat generating part 6 contributes to uniformly heating the object to be heated, like the heat generating part 5.

It can be said that it is desirable that the radius of curvature R of the portion 10 bent in the direction away from the tape-shaped heated body 3 is as small as possible, that is, R is close to a right angle. This is because the adjacent ceramic heating elements 1 can be arranged closer to each other.
Another effect of making the width of the heat generating part 6 at the crossing portion within ± 20% of the plate width of the heat generating part 5 is that the plate width of the heat generating part 6 is narrower than the terminal part 2, so L-shaped bending becomes possible, and heating elements to be arranged in a column can be arranged closer to each other. However, the ceramic heating element 1 has a problem that it is difficult to process, and an extreme R design causes cracks.
As described above, it is possible to obtain a ceramic plate-like heating element 1 in which a plurality of plate-like heating elements 1 arranged in the longitudinal direction of the heated body 3 are aligned with the same width. Further, since the plurality of ceramic plate-like heating elements 1 of the present invention can have the same shape, there is an advantage that the manufacturing can be standardized and the cost can be reduced.

Moreover, since the ceramic plate-shaped heating element 1 of the present invention is literally plate-shaped, there is an advantage that the thermal efficiency for raising the temperature of the heated object is the best. Moreover, temperature control can be performed for each heating element, and the temperature can be arbitrarily set in the longitudinal direction. When processing a wide tape-shaped object to be heated, a plurality of plate-like heating elements can be aligned not only in the longitudinal direction but also in the width direction.
In general, when a plurality of heating elements are assembled to heat an object to be processed, the central area is often heated to a higher temperature than the surrounding area due to the influence of heat from the surrounding heating elements. Since each body can be controlled, uniform heating is facilitated.
Furthermore, the plate thickness of the ceramic plate-like heating element of the present invention is 1 to 5 mm, the total plate width of the plate-like heating elements arranged in the longitudinal direction is 10 to 40 mm, the slit clearance is 10 mm or less, and the plate width of the high-temperature heating portion Is preferably 3 to 20 mm.

Of course, it is possible to manufacture a ceramic plate-like heating element outside this numerical range. However, especially for a heating element for forming a thin film on a tape-like object to be heated by an MOCVD apparatus or the like, the above numerical value range is used. Is preferred.
In general, a plurality of tape-like heated bodies move continuously or intermittently, and a plurality of plate-like heating elements are arranged along the longitudinal direction of the heated bodies. FIG. 2 shows an example in which a total of 15 ceramic plate-like heating elements 1 are arranged.
FIG. 2 does not clearly show the heat generating part formed by forming a slit or the L-shaped terminal part provided with a notched void, but the adjacent L-shaped terminal part and the terminal part of the ceramic plate-like heating element 1 The exothermic parts of each other cross each other without contact. FIG. 3 shows an example in which a thin film is formed on the surface of such a ceramic plate-like heating element 1 by moving five rows of tape-like objects to be heated continuously or intermittently.

Drums 23 are provided on the left and right, and are wound after, for example, five turns. Reference numeral 22 denotes an apparatus for supplying a thin film forming substance.
As described above, MoSi ₂ , SiC, or lanthanum chromite ceramics can be used for the plate-like heating element, and high purity MoSi ₂ or SiC ceramics are particularly desirable. It is desirable that the contents of Fe, Ni, and Cr, which are impurities contained in the ceramics, are 200 ppm or less, and the contents of Na and K are 20 wtppm or less, respectively.

When a high-purity MoSi ₂ or high-purity SiC heating element is used, there is no emission of contaminants from the heating element, and there is no deterioration or deterioration of properties due to contamination of the film-formed or heat-treated material. It is. In addition, it can be made of a material resistant to oxidation resistance and thermal shock, can generate heat to ultra-high temperature in a short time, and rapid temperature rise increases processing speed, increasing production speed and reducing cost The following advantages can be obtained.

  The ceramic plate-like heating element of the present invention has a remarkable effect that a tape-like object to be heated can be efficiently heated in a short time, temperature control is easy, and uniform heating is possible. It is optimal for heating the tape-shaped substrate when continuously formed.

It is a partial explanatory view at the time of combining two ceramic plate-like heating elements of the present invention. It is a figure which shows the example at the time of arranging 15 plate-shaped heat generating bodies made from ceramics of this invention. It is a figure which shows the example of the thin film formation apparatus in the case of heating several (5) tapes simultaneously. It is a schematic diagram which shows the conventional heating apparatus of the type which heats a tape through a quartz tube.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Ceramic plate-shaped heating element 2 Terminal part 3 Tape-like to-be-heated body 4 Slit (opening part)
DESCRIPTION OF SYMBOLS 5 Heat generation part 6 Heat generation part near terminal part 7 Space 8 Edge of heat generation part near terminal part 9 Edge of ceramic plate-like heating element 10 Bending part 11 Electrode part 20 Quartz tube 21 Tape 22 Supplying thin film forming substance Equipment to do 23 drums 24 mantle heaters

Claims (12)

A part of the heat generating part (6) in the vicinity of the terminal part in the direction in which the power supply terminal parts (2) at both ends are separated from the tape-like heated object (3) on one side of the tape-shaped heated object (3) Is a ceramic plate-like heating element in which a plurality of plate-like heating elements (1) having bent portions (10) bent in an L shape are arranged in the longitudinal direction of the body to be heated (3) , by forming a plurality of slits in the width direction of the body (1) alternately, substantially the entire central plate-like heating element, U-shaped or U-shaped continuous when viewed from the plane of the plate-like heating element (1) M-shaped narrow-width heat generating portions (5) are provided, and the bent portions (10) bent in the L shape of the adjacent plate-shaped heat generating elements (1) intersect each other without contacting each other. A plate-shaped heating element made of ceramics, characterized in that it is arranged in the manner described above. The R of the bent portion (10) of the plate-like heating element (1) bent in an L shape in a direction away from the tape-shaped heated body (3) is 10 mm or less. Ceramic plate-like heating element. 3. The ceramic plate-like heating element according to claim 1, wherein the thickness of the terminal part (2) of the plate-like heating element (1) is equal to or less than 5 mm equal to the thickness of the heating part (5) . Bent portions are bent in an L-type (10), on the side that intersects the adjacent plate-like heating element (1), the bent portion that is bent in an L-shaped adjacent plate-like heating element (1) (10 ) and ceramic plate-like heating element according to any one of claims 1 to 3, characterized in that it comprises a cut out space to avoid contact (7) of the. The ceramic plate according to any one of claims 1 to 4, wherein a plurality of plate-like heating elements (1) arranged in the longitudinal direction of the body to be heated (3) are arranged in tandem with the same width. Heating element. Terminal of the plate-like heating element (1) provided with a notched space (7) for avoiding contact with the bent portion (10) bent in the L shape of the adjacent plate-like heating element (1) The outer edge portion (8) of the heat generating portion (6) in the vicinity of the portion is aligned with the outer edge portion (9) of the plurality of aligned plate-like heating elements (1). A ceramic plate-like heating element according to any one of the above. Terminal of the plate-like heating element (1) provided with a notched space (7) for avoiding contact with the bent portion (10) bent in the L shape of the adjacent plate-like heating element (1) heat generating portion of the section near the width (6), according to claim 1, characterized in that the plate width of the other of the heat generating portion (5) is in the range of 100 ± 20% Ceramic plate-like heating element. The plate-like heating element (1) has a plate thickness of 1 to 5 mm, the plate-like heating elements (1) arranged in the longitudinal direction have a total plate width of 10 to 40 mm, and a slit clearance of 10 mm or less. Item 8. A ceramic plate-like heating element according to any one of Items 1 to 7. The plate-like heating element made of ceramics according to any one of claims 1 to 8, wherein a plate width of the heating part (5) is 3 to 20 mm. A plurality of tape-like heated bodies (3) move continuously or intermittently, and plate-like heating elements (1) are arranged in a plurality of rows and columns along the longitudinal direction of the heated body (3). The ceramic plate-like heating element according to any one of claims 1 to 9. Plate-like heating element (1) is, MoSi ₂ system, ceramic plate-like heating element according to any one of claims 1 to 10, characterized in that it consists of a SiC-based or lanthanum chromite-based ceramics. Plate-like heating element (1) is made of a high-purity MoSi ₂ system or SiC-based ceramics, the impurities contained in the ceramic, Fe, Ni, Cr content 200ppm or less, respectively, Na, the content of K respectively It is 20 wtppm or less, The ceramic plate-shaped heating element in any one of Claims 1-11 characterized by the above-mentioned.

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