JP2006118017A - Metal-evaporating heater - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a metal-evaporating boat which has improved wettability to a molten metal and has the extended life. <P>SOLUTION: The metal-evaporating heater has a plurality of flutes which are arranged in not a parallel direction to a passing current direction and have significantly different depths, on the top face of a ceramic sintered compact containing titanium diboride (TiB<SB>2</SB>) and/or zirconium diboride (ZrB<SB>2</SB>), and boron nitride (BN). In the heater, it is preferable that (1) the depths of the flute are significantly different in one flute, or between the flutes, (2) the difference of the depth of the flute is 10% or more, particularly 30% or more, with respect to the depth of the deepest part of the flute, (3) the flute having the deepest part among a plurality of flutes is arranged at a central part or in the vicinity of the center of the ceramic sintered compact in a longitudinal direction, (4) the flute having the shallowest part among a plurality of flutes is arranged on one end or both ends of the ceramic sintered compact in a longitudinal direction, and (5) the number of the flutes is 10 or more. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a metal vapor deposition heating element.

Conventionally, as a metal evaporation heating element (hereinafter also referred to as “boat”), for example, a ceramic sintered body mainly composed of boron nitride (BN), aluminum nitride (AlN), and titanium diboride (TiB ₂ ). Is known in which a cavity is formed on the upper surface (Japanese Patent Publication No. 53-20256). As an example of the commercial product, there is a trade name “BN Composite EC” manufactured by Denki Kagaku Kogyo. In this method of use, both ends of the boat are connected to the electrodes with clamps to generate voltage and heat is generated, and a metal such as an Al wire rod placed in the cavity is melted and evaporated to obtain a deposited film and cooled. Such an operation is repeated, and during that time, it is subjected to a cooling cycle and erosion by the molten metal, resulting in a lifetime.

The life of the boat is greatly related to the wettability of the molten metal to the boat. If the wettability is poor, the molten metal is localized and the original deposition efficiency of the boat cannot be obtained, and the corrosion of the molten metal to the boat progresses. Increases speed and shortens boat life. Therefore, in order to ensure the wettability of the boat, various devices such as laser irradiation have been performed, but a sufficient lifespan has not been achieved. In addition, laser irradiation requires a large amount of equipment and facilities. In order to solve this problem, the present applicant has previously proposed a boat in which one or more grooves are provided on the upper surface of the ceramic sintered body in a direction not parallel to the energizing direction (Patent Document 1).
Japanese Patent Application No. 2004-008217

  An object of the present invention is to provide a metal evaporation heating element (boat) that can improve wettability to molten metal and achieve a long life.

In the present invention, on the upper surface of the ceramic sintered body containing titanium diboride (TiB ₂ ) and / or zirconium diboride (ZrB ₂ ) and boron nitride (BN), in a direction not parallel to the energizing direction, A metal evaporation heating element, wherein a plurality of grooves are provided with a significant difference in the depth of the grooves.

In this invention, it is preferable to provide 1 or 2 or more chosen from the following embodiment (1)-(11).
(1) There is a significant difference in groove depth in one groove or between grooves.
(2) A significant difference in the depth of the groove is 10% or more, particularly 30% or more with respect to the depth of the deepest portion of the groove.
(3) Of the plurality of grooves, the groove having the deepest portion is provided in the central portion or the vicinity thereof with respect to the longitudinal direction of the ceramic sintered body.
(4) Of the plurality of grooves, a groove having the shallowest portion is provided at one or both ends with respect to the longitudinal direction of the ceramic sintered body.
(5) The number of grooves is 10 or more.
(6) The direction not parallel to the energizing direction is 20 to 160 degrees, particularly 60 to 120 degrees with respect to the energizing direction.
(7) Crossing the grooves so that there is at least one intersection.
(8) The ceramic sintered body has a cavity, and has a groove on the bottom surface of the cavity and / or the upper surface of the ceramic sintered body.
(9) A pattern is drawn with a plurality of grooves on the bottom surface of the cavity and / or the top surface of the ceramic sintered body.
(10) Occupied area ratio of the pattern is 30% or more, particularly 50% or more with respect to the top area of the ceramic sintered body with respect to the cavity bottom area for those having cavities, and with respect to the top area of the ceramic sintered body for those without cavities. And 80% or more.
(11) The groove has a width of 0.1 to 1.5 mm, a length of 1 mm or more, and a depth of 0.03 to 1.0 mm, and the difference in the depth of the groove is the depth of the deepest part of the groove. On the other hand, it is 10% or more, particularly 30% or more, and 0.005 mm or more, particularly 0.01 mm or more.

  ADVANTAGE OF THE INVENTION According to this invention, the boat which can improve the wettability with respect to a molten metal and can achieve lifetime improvement is provided.

  The composition of the ceramic sintered body used in the present invention contains at least a conductive material of titanium diboride and / or zirconium diboride and an insulating material of boron nitride as at least essential components. Conductive substances such as titanium nitride, silicon carbide, and chromium carbide, and insulating substances such as aluminum nitride, silicon nitride, alumina, silica, and titanium oxide can be appropriately contained.

  Among them, titanium diboride and / or zirconium diboride and boron nitride are the main components, or titanium diboride and / or zirconium diboride, boron nitride, and aluminum nitride. The main component is preferable. Particularly preferably, titanium diboride and / or zirconium diboride 30 to 60% (% is mass%, the same shall apply hereinafter) and boron nitride 70 to 40%, or titanium diboride and / or Alternatively, those containing 35 to 55% zirconium diboride, 25 to 40% boron nitride, and 5 to 40% aluminum nitride are preferable. With such a composition, the ceramic sintered body can be extremely easily processed.

  The relative density of the ceramic sintered body is preferably 90% or more, particularly 93% or more. If the relative density is remarkably smaller than 90%, the molten metal may erode into the pores of the ceramic sintered body, which may promote erosion. Realization of a relative density of 90% or more is facilitated by adding a sintering aid described later to the above composition within a range not exceeding 10%. The relative density of the ceramic sintered body is obtained by processing the sintered body into a rectangular parallelepiped having a predetermined size and dividing the measured density obtained from the outer size and mass by the theoretical density.

  The ceramic sintered body used in the present invention can be manufactured by molding and sintering a mixed raw material powder containing a conductive material of titanium diboride and / or zirconium diboride and an insulating material of boron nitride. .

  The raw material titanium diboride powder may be obtained by any manufacturing method such as a direct reaction with titanium metal or a method using a reduction reaction of an oxide such as titania. The average particle size is preferably 5 to 25 μm.

  The boron nitride powder is preferably hexagonal boron nitride, amorphous boron nitride, or a mixture thereof. This is produced by heating a mixture of borax and urea in an ammonia atmosphere at 800 ° C. or higher, or heating a mixture of boric acid or boron oxide and calcium phosphate at 1300 ° C. or higher with a nitrogen-containing compound such as ammonium or dicyandiamide. can do. Further, boron nitride powder may be heated at a high temperature in a nitrogen atmosphere to improve crystallinity. The average particle size of the boron nitride powder is preferably 10 μm or less, particularly preferably 5 μm or less.

  The aluminum nitride powder may be produced by a direct nitriding method, an alumina reduction method or the like, and the average particle size is preferably 10 μm or less, particularly preferably 7 μm or less.

As the sintering aid, one kind or two or more kinds of powders selected from the group consisting of alkaline earth metal oxides, rare earth element oxides, and compounds that become these oxides upon heating are used. _{Specifically, CaO, MgO, SrO, BaO} , Y 2 O 3, La 2 O 3, Ce 2 O 3, Pr 2 O 3, Nd 2 O 3, Pm 2 O 3, Sm 2 O 3, Eu 2 O ₃ , Gd ₂ O ₃ , Tb ₂ O ₃ , Dy ₂ O ₃ , Ho ₂ O ₃ , Er ₂ O ₃ , Tm ₂ O ₃ , Yb ₂ O ₃ , Lu ₂ O ₃ etc., and further Ca (OH) Examples thereof include hydroxides such as ₂ and carbonates such as MgCO ₃ , and compounds that become these oxides upon heating. The average particle size of the sintering aid is preferably 5 μm or less, particularly preferably 1 μm or less.

  The mixed raw material powder containing the above components is preferably granulated and then molded and sintered. As an example of molding / sintering conditions, after uniaxial or cold isostatic pressing of 0.5 to 200 MPa, normal pressure sintering at a temperature of 1800 to 2200 ° C. or low pressure sintering of 1 MPa or less It is. Further preferable examples include a hot press or a hot isostatic press of 1800 to 2200 ° C. and 1 to 100 MPa.

  Sintering is preferably carried out in a graphite container, a boron nitride container, a container lined with boron nitride, or the like. In the hot pressing method, sintering is preferably performed using a graphite or boron nitride sleeve, a sleeve lined with boron nitride, or the like.

  In order to manufacture a boat from a ceramic sintered body, for example, it can be performed by processing into a suitable shape by machining or the like. Moreover, the boat of this invention can also provide a cavity in the approximate center part of the upper surface of a ceramic sintered compact. If an example of a boat shape is shown, it will be a plate-shaped body with an overall dimension of 100-200 mm in length, width (width) 25-35 mm, and thickness 8-12 mm. When a cavity is provided, examples of the cavity include a rectangular shape having a length of 90 mm to 120 mm, a width (width) of 20 to 32 mm, and a depth of 0.5 to 2 mm.

  The boat of the present invention is parallel to the energization direction (that is, the direction connecting the electrodes) to the upper surface of the ceramic sintered body, and to the bottom surface of the cavity and / or the upper surface of the ceramic sintered body in the case of having a cavity. It has a plurality of grooves in the direction which is not. As a result, wetting and spreading in the direction parallel to the energizing direction is further suppressed, wetting and spreading in the direction orthogonal to the energizing direction is promoted, and wettability is further improved.

  The angle in a direction not parallel to the energizing direction is preferably 20 to 160 degrees, particularly 60 to 120 degrees with respect to the energizing direction.

  The shape of the groove is preferably a linear shape having a rectangular cross section. For example, the groove has a width of 0.1 to 1.5 mm, a length of 1 mm or more, a depth of 0.03 to 1 mm, and particularly a width. 0.3 to 1 mm, length is 10 mm or more, and depth is 0.05 to 0.2 mm. The number of grooves is preferably 10 or more, particularly 30 or more, and more preferably 50 or more. The interval between the grooves is preferably 2 mm or less, particularly preferably 0.5 to 1.5 mm.

  In the present invention, the grooves are intersected, and at least one intersection is formed, preferably the number of intersections equal to or more than the number of grooves, or the top surface of the ceramic sintered body and / or the bottom surface of the cavity is, for example, circular or elliptical. It is preferable to draw various patterns (planar patterns) such as a shape, a rhombus, a rectangle, a moon, a lattice, and a radial pattern with a plurality of grooves. The area occupied by the pattern is 30% or more, particularly 50% or more with respect to the top area of the ceramic sintered body with respect to the cavity bottom area for those having a cavity, Is preferably 80% or more.

  In the present invention, the occupied area ratio of the pattern is defined as a percentage of a value obtained by dividing the area formed by connecting the outermost grooves with the upper area of the ceramic sintered body or the bottom area of the cavity. . Instead of the pattern occupation area ratio, the groove occupation area per unit area of the ceramic sintered body or the bottom area of the cavity is expressed as a percentage of 10% or more, particularly 30% or more, and more preferably 50% or more. Is preferred.

  In the boat of the present invention, in order to prevent a molten metal such as aluminum from creeping out from the side surface, even if a cavity such as a boat shape is formed on the upper surface of the ceramic sintered body as in the conventional structure, Good. In the present invention, the cavity is not always necessary, but in the case of having the cavity, the groove is preferably formed at least on the bottom surface of the cavity.

  By forming a plurality of grooves as described above, the wettability of the molten metal in the direction parallel to the energizing direction is suppressed and the arrival of the molten metal to the electrode can be significantly delayed compared to a boat without grooves. As a result, metal evaporation can be stabilized and highly efficient. A feature of the present invention is that a boat having a plurality of grooves has a significant difference in the depth of the grooves, thereby promoting the wettability of the molten metal.

  In the present invention, the significant difference in the depth of the groove can be expressed as a percentage of (depth of the deepest portion of the groove−depth of the shallowest portion of the groove) / (depth of the deepest portion of the groove). it can. In this equation, the groove used to measure the depth of the deepest part of the groove and the groove used to measure the depth of the shallowest part of the groove may be the same or different. Also good. In the present invention, the significant difference of the grooves according to the above formula is preferably 10% or more, particularly 30% or more. Further, irrespective of the above formula or in relation to the above formula, (the depth of the deepest part of the groove−the depth of the shallowest part of the groove) is 0.005 mm or more, particularly 0.1 mm or more. preferable.

  In the present invention, in order to provide a significant difference in the depth of the groove, (b) among the plurality of grooves, a significant difference in the groove depth is provided in at least one of the grooves. It is performed by providing a significant difference in the depth of the groove between them, or (c) a combination of both.

  According to the method (a), the groove difference is determined according to the above equation. In this case, it is preferable that the deepest part of the groove is between 10% to 80%, particularly 40% to 60% with respect to the longitudinal direction of the groove, and the shallowest part is located at a position outside these ranges. .

  In the case of the method (b), the groove for which “the deepest part of the groove” is obtained may be the same as or different from the groove for which “the shallowest part of the groove” is obtained. Further, all of the plurality of grooves may be grooves having a uniform depth without the deepest portion and the shallowest portion, or at least one of the plurality of grooves has a non-uniform depth as shown in (a). It may have a groove. (C) is a special embodiment of these, and has a structure in which a groove having a uniform depth and a groove having a non-uniform depth are combined.

  In (b) or (c), deeper grooves (including grooves having the deepest part) and shallower grooves (grooves including the shallowest part) are provided, for example, alternately, every two or more, and randomly. Etc. are totally free. However, the groove having the deepest portion is preferably provided in the central portion or the vicinity thereof with respect to the longitudinal direction of the ceramic sintered body. Here, the central portion or its vicinity with respect to the longitudinal direction is preferably, for example, a position of 20 to 80%, particularly 30 to 70%, more preferably 40 to 60% with respect to the longitudinal direction. And it is preferable to provide a groove having a shallower depth than the deeper groove (including the groove having the deepest portion) disposed in the above-mentioned area in the area other than these areas. In particular, it is more preferable that the groove which becomes the end at one end or both ends with respect to the longitudinal direction of the ceramic sintered body is a groove having the shallowest portion.

  The groove can be processed by a method such as machining, sand blasting, or water jet.

  The perspective view which shows an example of the boat of this invention was shown in FIGS. The direction of the groove is 20 to 160 degrees with respect to the energization direction of the ceramic sintered body. The boat of FIG. 2 has an intersection, and the other boats have no intersection. The boats of FIGS. 1, 2, 5 and 6 have cavities and the other boats have no cavities.

  The boat of FIG. 1 is provided with a cavity 26 mm wide × 1 mm deep × 120 mm long at the center of the upper surface of a ceramic sintered body made of a rectangular prism having a length of 150 mm × width of 30 mm × thickness of 10 mm. On the bottom surface, 50 grooves having a length of 20 mm, a width of 1 mm, and different depths are provided at intervals of 1 mm and 90 degrees with respect to the energizing direction. In the examples, the groove depth (not shown) was variously changed to provide a significant difference in the groove depth.

  The boat shown in FIG. 2 has 35 grooves each having a width of 1 mm, a depth of 0.15 mm, and a length of 28 mm at 45 ° with respect to the energization direction on the bottom surface of the cavity of the boat and energization perpendicular to the grooves. 1 except that 35 grooves having a width of 1 mm, a depth of 0.10 mm, and a length of 28 mm having an inclination of 135 degrees with respect to the direction are provided so as to intersect with each other.

  The boat shown in FIG. 3 has a plurality of grooves (total 30) inclined by 90 degrees with respect to the energizing direction by continuous grooves having a length of 645 mm, a width of 1.5 mm and different depths without forming a cavity. It is the same as FIG. 1 except that it is provided in a striped pattern. The groove having a depth of 0.20 mm is provided only at a position of 40 to 60% with respect to the longitudinal direction of the ceramic sintered body, and the groove having a depth of 0.15 mm is provided at a position other than the above.

  The boat shown in FIG. 4 has 24 grooves at a 1 mm interval, a width of 1.0 mm, a depth of 0.10 mm, and a length of 1.0 mm, a depth of 0.15 mm, and a length of 25 mm without forming a cavity. 1 except that 25 mm grooves are provided alternately at intervals of 1 mm as grooves having a depth of 0.10 mm at both ends, and both grooves are provided at 90 degrees with respect to the energizing direction. .

  In the boat of FIG. 5, 26 grooves of a maximum length of 24 mm, a width of 1 mm, and a depth of 0.15 mm are formed on the bottom surface of the cavity at 90 degrees with respect to the energizing direction at or near the center of the ceramic sintered body. On the other hand, on the right and left sides, 12 grooves each having a width of 1 mm and a depth of 0.10 mm (a total of 24 grooves) are provided at an angle of 90 mm with respect to the energizing direction. 1 is the same as FIG.

  The boat of FIG. 6 has 30 grooves 20 mm long, 1 mm wide, and 0.15 mm deep on the bottom surface of the cavity and the upper surface of the boat other than the cavity. On the right and left sides, 15 grooves with a length of 20 mm, a width of 1 mm, and a depth of 0.10 mm (30 in total) are provided at 90 degrees with respect to the energizing direction. Except that, it is the same as FIG.

  The boat of FIG. 7 is provided with 30 grooves of 19 mm in length, 1 mm in width, and 0.15 mm in depth on the ceramic sintered body at an interval of 1.5 mm and 90 degrees with respect to the energizing direction. On both sides, there are 14 grooves (total of 28) with a length of 25 mm, a width of 1 mm, and a depth of 0.10 mm, with a spacing of 1.5 mm and 90 degrees with respect to the energizing direction. On both sides, grooves of length 27 mm, width 1 mm, depth 0.05 mm are provided at four intervals of 90 mm with respect to the energizing direction at 1.5 mm intervals (total of 8), while parallel to the energizing direction. In the direction, a groove with a width of 1 mm, a depth of 0.15 mm, and a length of 130 mm is provided on each edge, and a groove with a width of 1 mm, a depth of 0.15 mm, and a length of 65 mm is provided on both edges at the inner center. Example 1 is the same as Example 1 except that one is provided in each part.

An example of how to use the boat of the present invention is to form a metal vapor deposition film on a film or the like by heating in a vacuum while supplying a metal such as an Al wire in contact with a part or all of the groove of the boat. . If an example of conditions for vacuum heating is shown, the degree of vacuum is preferably 1 × 10 ⁻¹ to 1 × 10 ⁻³ Pa, and the temperature is preferably 1400 to 1600 ° C.

Examples 1-3
A mixed raw material powder of 45% titanium diboride powder (average particle size 12 μm), boron nitride powder (average particle size 0.7 μm), 30% by mass and aluminum nitride powder (average particle size 10 μm) is made of graphite. The die was filled and hot pressed at a temperature of 1750 ° C. to produce a ceramic sintered body (relative density 94.5%, diameter 200 mm × height 20 mm). From this ceramic sintered body, the boat shown in FIG. 1 was manufactured by machining. The groove depth (not shown) was changed to provide various significant differences in the groove depth.

Examples 4-6
A boat was manufactured in the same manner as in Example 1, 2, or 3 except that the cavity was not formed.

Example 7
For a single groove, except that the central portion of the groove in the longitudinal direction has a depth of 0.15 mm, both sides have a depth of 0.10 mm, and 50 such grooves are provided. Produced a boat in the same manner as in Example 1.

Comparative Examples 1 and 2
A boat was manufactured in the same manner as in Example 1 or 4 except that a groove having a depth of 0.15 mm was uniformly formed without providing a significant difference in the groove depth.

In order to evaluate the wettability of the boat obtained above with respect to the molten metal, the applied voltage was determined and set so that the boat end was connected to an electrode with a clamp and the temperature at the center of the boat was 1600 ° C. Next, a voltage was applied to the boat and heated, and under a vacuum of 1 × 10 ⁻² Pa, an aluminum wire was supplied to the groove at a rate of 6.5 g / min for 5 minutes to continue heating. Five minutes after the start of aluminum supply, the upper surface of the boat was photographed, and the width (mm) and the maximum length (mm) of the central portion were measured for the spread of the molten metal. The results are shown in Table 1.

The boat life was also evaluated. That is, the temperature at the center of the boat is 1500 ° C., and an evaporation test is performed in a vacuum of 2 × 10 ⁻² Pa while supplying aluminum wire at a rate of 6.5 g / min for 40 minutes as a unit cycle. The operation was repeated. The number of repetitions when the erosion depth on the aluminum evaporation surface of the boat reached a maximum of 3 mm was taken as the life of the boat. The results are shown in Table 1.

The boat and the metal evaporation method of the present invention are used to deposit various metals on, for example, a film.

The perspective view which shows an example of the boat of this invention. The perspective view which shows an example of the boat of this invention. The perspective view which shows an example of the boat of this invention. The perspective view which shows an example of the boat of this invention. The perspective view which shows an example of the boat of this invention. The perspective view which shows an example of the boat of this invention. The perspective view which shows an example of the boat of this invention

Claims (12)

The depth of the groove on the upper surface of the ceramic sintered body containing titanium diboride (TiB ₂ ) and / or zirconium diboride (ZrB ₂ ) and boron nitride (BN) in a direction not parallel to the energizing direction. A metal evaporation heating element, wherein a plurality of grooves are provided with a difference in orientation.   The metal evaporation heating element according to claim 1, wherein a significant difference is made in the depth of the groove in one groove or between the grooves.   3. The metal evaporation heating element according to claim 1, wherein a significant difference in the depth of the groove is 10% or more with respect to the depth of the deepest portion of the groove.   The metal evaporation heating element according to any one of claims 1 to 3, wherein, among the plurality of grooves, the groove having the deepest portion is provided in the central portion or the vicinity thereof with respect to the longitudinal direction of the ceramic sintered body. .   The metal evaporation heating element according to any one of claims 1 to 4, wherein a groove having the shallowest portion among the plurality of grooves is provided at one end or both ends with respect to the longitudinal direction of the ceramic sintered body.   6. The metal evaporation heating element according to claim 1, wherein the number of grooves is 10 or more.   The metal evaporation heating element according to any one of claims 1 to 6, wherein a direction not parallel to the energization direction is 20 to 160 degrees with respect to the energization direction.   The metal evaporation heating element according to any one of claims 1 to 7, wherein the grooves are crossed so that at least one intersection is formed.   9. The metal evaporation heating element according to claim 1, wherein the ceramic sintered body has a cavity, and a plurality of grooves are provided on the bottom surface of the cavity and / or the upper surface of the ceramic sintered body. .   The metal evaporation heating element according to any one of claims 1 to 9, wherein a pattern is drawn by a plurality of grooves on the bottom surface of the cavity and / or the top surface of the ceramic sintered body.   The occupation area ratio of the pattern is 30% or more with respect to the cavity bottom area for those having cavities and 30% or more with respect to the top area of the ceramic sintered body for those without cavities, respectively. Item 11. The metal evaporation heating element according to any one of Items 1 to 10.   The groove has a width of 0.1 to 1.5 mm, a length of 1 mm or more, and a depth of 0.03 to 1.0 mm, and the positional difference of the groove depth is 10 with respect to the depth of the deepest part of the groove. % Or more, and 0.005 mm or more, The metal evaporation heating element according to claim 1.

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