Title of Invention

METAL EVAPORATION HEATING ELEMENT AND METHOD FOR EVAPORATING METAL

Abstract There is disclosed a metal evaporation heating element having one or more grooves in a direction not in parallel with a current direction, on an upper surface of a sintered body, wherein the groove has a width of from 0.l to 1.5 mm, a depth of from 0.03 to 1 mm and a length of at least 1 mm, characterized in that the sintered body is a ceramic sintered body comprising titanium diboride (TiB2) and/or zirconium diboride (ZrB2), and boron nitride (BN), and in that the direction not in parallel with the current direction makes an angle of from 60 to 120° with the current direction.
Full Text DESCRIPTION
METAL EVAPORATION HEATING ELEMENT AND METHOD FOR
EVAPORATING METAL
TECHNICAL FIELD
The present invention relates to a metal evaporation
heating element and a method for evaporating a metal.
BACKGROUND ART
Heretofore, as a metal evaporation heating element
(hereinafter sometimes referred to as ^*boat"), for
example, an electrically conductive ceramic sintered body-
comprising boron nitride (BN), aluminum nitride (AlN) and
titanium diboride {TiB2) as the main components and
having a cavity formed on the upper surface thereof has
been known (JP-B-53-20256). As one example of commercial
products, "BN COMPOSITE EC", tradename, manufactured by
Denki Kagaku Kogyo Kabushiki Kaisha may be mentioned.
As a method of using the boat, each end of the boat
is connected to an electrode by a clamp, a voltage is
applied to generate heat, and a metal such as an Al wire
rod put in the cavity is melted and evaporated to obtain
a deposited film, followed by cooling. Such an operation
is repeatedly carried out, during which the boat
undergoes temperature cycles and erosion by the molten
metal, and it will reach the end of its usefulness.
The boat life greatly relates to wettability of the
boat to the molten metal, and if the wettability is poor,
not only the molten metal is localized and no evaporation
efficiency inherent in the boat will be obtained, but
also the progress of erosion of the boat by the molten
metal will be accelerated, whereby the boat life will be
shortened. Accordingly, in order to secure the
wettability of the boat, various attempts have been made
such as irradiation with laser (JP-A-2000-93788), but no
sufficient prolongation of life has been achieved.
Further, extensive apparatus and facility will be
required for irradiation with laser.
DISCLOSURE OF THE INVENTION
OBJECT TO BE ACCOMPLISHED BY THE INVENTION
It is an object of the present invention to provide
a metal evaporation heating element (boat) which has
improved wettability to a molten metal and which has a
prolonged life, and a method for evaporating a metal
using it.
(1) A metal evaporation heating element characterized by
having one or more grooves in a direction not in parallel
with a current direction, on an upper surface of a
ceramic sintered body comprising titanium diboride (TiB2)
and/or zirconium diboride (ZrB2) , and boron nitride (BN),
wherein the groove has a width of from 0.1 to 1.5 mm, a
depth of from 0.03 to 1 mm and a length of at least 1 mm.
(2) The metal evaporation heating element according to
the above (1), characterized by having at least two
grooves with a distance of at most 2 mm.
(3) The metal evaporation heating element according to
the above (1) or (2), characterized in that the number of
grooves is at least 10.
(4) The metal evaporation heating element according to
any one of the above (1) to (3), characterized in that
the direction not in parallel with the current direction
makes an angle of from 20 to 160° with the current
direction.
(5) The metal evaporation heating element according to
the above (4), characterized in that the grooves are
crossed so as to form at least one intersection.
(6) The metal evaporation heating element according to
any one of the above (1) to (5), characterized in that
the ceramic sintered body has a cavity, and the groove is
formed on the bottom surface of the cavity and/or on the
upper surface of the ceramic sintered body.
(7) The metal evaporation heating element according to
any one of the above (1) to (6), characterized in that a
pattern is drawn by a plurality of grooves on the bottom
surface of the cavity and/or on the upper surface of the
ceramic sintered body.
(8) The metal evaporation heating element according to
the above (7), characterized in that the area ratio
occupied by the pattern is at least 30% to the bottom
surface area of the cavity with respect to one having a
cavity, or to the upper surface area of the ceramic
sintered body with respect to one having no cavity.
(9) The metal evaporation heating element according to
the above (8), characterized in that the area ratio
occupied by the pattern is at least 50%.
(10) The metal evaporation heating element according to
the above (8), characterized in that the area ratio
occupied by the pattern is at least 80%.
(11) The metal evaporation heating element according to
any one of the above (1) to (10), characterized in that
in one groove, or between different grooves, a
significant difference is provided in the depth of the
groove•
(12) The metal evaporation heating element according to
the above (11), characterized in that the significant
difference in the depth of the groove is at least 10%.
(13) The metal evaporation heating element according to
the above (11) or (12), characterized in that among a
plurality of grooves, the groove having the deepest
portion is provided at a center portion in the
longitudinal direction of the ceramic sintered body or in
the vicinity thereof.
(14) The metal evaporation heating element according to
any one of the above (11) to (13), characterized in that
among the plurality of grooves, the groove having the
shallowest portion is provided at one end or each end in
the longitudinal direction of the ceramic sintered body.
(15) The metal evaporation heating element according to
any one of the above (11) to (14), characterized in that
{(depth of the deepest portion of the groove) - (depth of
the shallowest portion of the groove)} is at least 0.005
mm.
(16) A method for evaporating a metal, characterized by
using the metal evaporation heating element as defined in
any one of the above (1) to (15) and heating a metal in
vacuum in a state where the metal is in contact with part
or all of the groove.

BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS
Fig. 1 is a perspective view illustrating one
example of the boat of the present invention.
Fig. 2 is a perspective view illustrating one
example of the boat of the present invention.
Fig. 3 is a perspective view illustrating one
example of the boat of the present invention.
Fig. 4 is a perspective view illustrating one
example of the boat of the present invention.
Fig. 5 is a perspective view illustrating one
example of the boat of the present invention.
Fig. 6 is a perspective view illustrating one
example of the boat of the present invention.
Fig. 7 is a perspective view illustrating one
example of the boat of the present invention.
Pig. 8 is a perspective view illustrating one
example of the boat of the present invention.
Pig. 9 is a perspective view illustrating one
example of the boat of the present invention.
Pig. 10 is a perspective view illustrating one
example of the boat of the present invention.
BEST MODE FOR CARRYING OUT THE INVENTION
As the composition of the ceramic sintered body to
be used in the present invention, it contains at least an
electrically conductive substance titanium diboride
and/or zirconium diboride and an insulating substance
boron nitride as essential components. An electrically
conductive substance such as titanium nitride, silicon
carbide or chromium carbide and an insulating substance
such as aluminum nitride, silicon nitride, alumina,
silica or titanium oxide may suitably be incorporated.
Among them, preferred is one containing as the main
components titanium diboride and/or zirconium diboride,
and boron nitride, or one containing as the main
components titanium diboride and/or zirconium diboride,
and boron nitride and aluminum nitride. Particularly .
preferred is one containing from 30 to 60% (hereinafter %
means mass% unless otherwise specified) of titanium
diboride and/or zirconium diboride and from 70 to 40% of
boron nitride, or one containing from 35 to 55% of
titanium diboride and/or zirconium diboride, from 25 to
40% of boron nitride and from 5 to 40% of aluminum
nitride. When the ceramic sintered body has such a
composition, it will very easily be processed.
Further, the ceramic sintered body has a relative
density of preferably at least 90%, particularly
preferably at least 93%. If the relative density is less
than 90%, the molten metal will erode the pores of the
ceramic sintered body, whereby erosion will be
accelerated. A relative density of at least 90% will be
easily realized by incorporating a sintering aid as
described hereinafter to the above composition within a
range not exceeding 10%. The relative density of the
ceramic sintered body is determined by processing the
sintered body into a rectangular solid having
predetermined dimensions and dividing the actually
measured density obtained from the outer dimensions and
the mass by the theoretical density.
The ceramic sintered body to be used in the present
invention can be produced by forming a material powder
mixture containing an electrically conductive substance
titanium diboride and/or zirconium diboride and an
insulating siibstance boron nitride and sintering the
mixture.
A material titanium diboride powder may be produced
by any production method such as a method of utilizing a
direct reaction with metal titanium or a reduction of an
oxide such as titania. The powder preferably has an
average particle size of from 5 to 25 µm.
A boron nitride powder is preferably hexagonal boron
nitride or amorphous boron nitride or a mixture thereof.
The powder may be produced, for example, by a method of
heating a mixture of borax with urea in an ammonia
atmosphere at 800°C or higher, or a method of heating a
mixture of boric acid or boron oxide with calcium
phosphate and a nitrogen-containing compound such as
ammonium or dicyandiamide at 1,300°C or higher. Further,
the boron nitride powder may be heated at high
temperature in a nitrogen atmosphere thereby to increase
crystallinity. The boron nitride powder has an average
particle size of preferably at most 10 µm, particularly
preferably at most 5 µm.
An aluminum nitride powder may be produced by a
direct nitriding method or an alumina reduction method,
and it has an average particle size of preferably at most
10 µm, particularly preferably at most 7 µm.
As a sintering aid, one or more powders selected
from the group consisting of an alkaline earth metal
oxide, an oxide of a rare earth element and a compound to
be converted to such an oxide by heating. Specifically,
it may, for example, be CaO, MgO, SrO, BaO, Y2O3, La2O3 ,
Ce2O3, Pr2O3, Nd2O3, Pm2O3, Sm2O3, EU2O3, Gd2O3, Tb2O3, Dy2O3,
HO2O3, Er2O3, Tm2O3, Yb2O3 or LU2O3, or a compound to be
converted to such an oxide by heating, such as a
hydroxide such as Ca(0H)2 or a carbonate such as MgCO3.
The sintering aid has an average particle size of
preferably at most 5 µm, particularly preferably at most
1 µm.
The material powder mixture containing the above
components is preferably granulated, and then formed and
sintered. As one example of the forming and sintering
conditions, uniaxial pressing or cold isostatic pressing
under from 0.5 to 200 MPa is carried out, and then normal
pressure sintering or low pressure sintering under 1 MPa
or below is carried out at a temperature of from 1,800 to
2,200°C. As an example of more preferred conditions, hot
pressing or hot isostatic pressure under from 1 to 100
MPa is carried out at from 1,800 to 2,200°C.
Sintering is carried out preferably in a state where
the mixture is accommodated in a container made of
graphite, a container made of boron nitride, a container
lined with boron nitride, or the like. In the case of
hot pressing, sintering is carried out preferably by
using a sleeve made of graphite or boron nitride, a
sleeve lined with boron nitride, or the like.
Production of a boat from the ceramic sintered
product can be carried out, for example, by forming the
sintered body into a suitable shape by means of e.g.
mechanical processing. Further, in the boat of the
present invention, a cavity may be formed on a
substantially center portion on the upper surface of the
ceramic sintered body. As one example of the boat shape.
the boat has a plate shape having a whole dimension with
a length of from 100 to 200 mm, a width of from 25 to 35
mm and a thickness of from 8 to 12 mm. In a case where a
cavity is formed, the cavity may, for example, have a
rectangular shape having a length of from 90 to 12 0 mm, a
width of from 20 to 32 mm and a depth of from 0.5 to 2 mm.
The boat of the present invention has, on the upper
surface of the ceramic sintered body, or with respect to
one having a cavity, on the bottom surface of the cavity
and/or on the upper surface of the ceramic sintered body,
one or more grooves in a direction not in parallel with a
current direction (i.e. a direction connecting
electrodes), i.e. with a predetermined angle a with the
current direction which is the longitudinal direction of
the ceramic sintered body as shown in Fig. 1. By such a
groove, wetting in a direction in parallel with the
current direction will be suppressed, wetting in a
direction at right angles to current direction will be
accelerated, and wettability will further improve.
A suitable angle a in a direction not in parallel
with the current direction is, as shown in Figs. 1 to 10,
preferably from 20 to 160°, particularly preferably from
60 to 120° to the current direction. The groove
preferably has a linear shape with a rectangular cross
section preferably having a width of from 0.1 to 1.5 mm.
a depth of from 0.03 to 1 mm and a length of at least 1
mm, particularly preferably a width of from 0.3 to 1 mm,
a depth of from 0.05 to 0.2 mm and a length of at least
10 mm. Although only one groove can improve wettability
to a molten metal, the number of grooves is preferably at
least 2, particularly preferably at least 10, furthermore
preferably at least 30. In a case where there are two or
more grooves, the distance between the grooves is
preferably at most 2 mm, particularly preferably from 0.5
to 1.5 mm.
Particularly, it is preferred that the grooves are
crossed so as to form at least one intersection,
preferably intersections in the same or more number of
the grooves, or on the upper portion of the ceramic
sintered body and/or on the bottom of the cavity, a
pattern (planar pattern) such as a circular, elliptic,
rhomboidal, rectangular, mooned, lattice or radial
pattern is drawn by the grooves. The area ratio occupied
by the pattern is preferably at least 3 0%, particularly
preferably at least 50%, more preferably at least 80% to
the bottom surface area of the cavity with respect to one
having a cavity, or to the upper surface area of the
ceramic sintered body with respect to one having no
cavity. The area ratio occupied by the pattern is
defined as a percentage of a value obtained by dividing
the area formed by connecting outermost grooves forming
the pattern by the upper surface area of the ceramic
sintered body or the bottom surface area of the cavity.
When the area ratio occupied by the groove is employed
instead of the area ratio occupied by the pattern, the
area ratio occupied by the groove to the upper surface
area of the ceramic sintered body or the bottom surface
area of the cavity is preferably at least 10%,
particularly preferably at least 3 0%, more preferably at
least 50%.
Further, in the present invention, in one groove or
between different grooves to be formed on the ceramic
sintered body, a significant difference is preferably
provided in the depth of the groove. By the significant
difference, wettability to a molten metal will further be
accelerated. In the present invention, the significant
difference (%) in the depth of the groove is represented
by the following formula. A groove to be used to measure
the depth of the deepest portion of the groove and a
groove to be used to measure the depth of the shallowest
portion of a groove for the following formula may be the
same or different.
{(depth of the deepest portion of the groove) - (depth of
the shallowest portion of the groove)} x 100/(depth of
the deepest portion of the groove)
In the present invention, the significant difference
of the groove by the above formula is preferably at least
10%, more preferably at least 20%, particularly
preferably at least 30%. Further, regardless of the
above formula or in relation to the above formula, the
depth of the groove is suitably such that {(depth of the
deepest portion of the groove) - (depth of the shallowest
portion of the groove)} is preferably at least 0.005 mm,
particularly preferably at least 0.1 mm.
In the present invention, the significant difference
in the depth of the groove may be provided by (i)
providing a significant difference in the depth of the
groove in at least one groove among a plurality of
grooves, (ii) providing a significant difference in the
depth of the groove between two or more grooves, or (iii)
a combination thereof.
In the case of the above method (i), the deepest
portion in one groove is suitably provided preferably at
a center portion with a length of from 10 to 80%,
particular preferably at a center portion with a length
of from 40 to 6 0% in the longitudinal direction of the
groove, and the shallowest portion is suitably provided
at the other end portion in the longitudinal direction.
In the case of the above method (ii) , the groove
employed to determine "the deepest portion of the groove"
and the groove employed to determine "the shallowest
portion of the groove" may be the same or different.
Further, a plurality of grooves having different depths,
each having a uniform depth, may be provided, or at least
one groove among the plurality of grooves may be a groove
having a non-vmiform depth as in (i) . Further, in the
case of the above (iii), a groove having a uniform depth
and a groove having a non-uniform depth are combined.
Further, in the case of the above (ii) or (iii), a
deep groove (including a groove having the deepest
portion) and a shallow groove (including a groove having
the shallowest portion) are freely arranged, such that
they are alternately provided, two or more grooves and
two or more of the other types of grooves are alternately
provided, or they are randomly provided. However, a deep
groove (including a groove having the deepest portion) is
preferably provided at a center portion in the
longitudinal direction of the ceramic sintered body or in
the vicinity thereof. The center portion in the
longitudinal direction of the ceramic sintered body or in
the vicinity thereof, is preferably a center region with
a length of preferably from 20 to 80%, more preferably
from 30 to 70%, particularly preferably from 40 to 60%,
of the total length of the ceramic sintered body.
Further, it is preferred to provide a groove shallower
than the deep groove (including a groove having the
deepest portion) at an end region other than such a
center region. Particularly, in one or each end region
in the longitudinal direction of the ceramic sintered
body, the outermost groove preferably has the shallowest
portion.
In the present invention, it is particularly
preferred that a plurality of grooves having a width of
from 0.1 to 1.5 mm, a length of at least 1 mm and a depth
of from 0.03 to 1.0 mm are provided, the significant
difference in the depth of the groove is at least 10%,
and {(depth of the deepest portion of the groove) -
(depth of the shallowest portion of the groove)} is at
least 0.005 mm.
Processing of the groove on the ceramic sintered
body of the present invention may be carried out, for
example, by mechanical processing, sandblasting or water
jet.
The boat of the present invention has suppressed
wettability to a molten metal in a direction in parallel
with a current direction, by formation of the groove.
Thus, arrival of a molten metal to electrodes can be
remarkably reduced as compared with a conventional boat
having no groove, whereby the metal can be evaporated
stably with high efficiency.
On a conventional boat, a cavity is formed so as to
prevent the molten metal such as aluminum being dripping
from the side surface. However, in the present invention,
a cavity is one having grooves with different size or
function provided thereon. Therefore, the cavity is not
necessarily required in the present invention. However,
with respect to one having a cavity, the groove or a
pattern by the groove is formed preferably on at least
the bottom surface of the cavity. Perspective views
illustrating one example of the boat of the present
invention are shown in Figs. 1 to 10.
Boats in Figs. 1, 2, 3 and 4 are produced in
Examples 1, 3, 4 and 5, respectively. In each of the
boats, a pattern is drawn by groove(s), and the area
ratios occupied by the pattern are 64% and 76% to the
bottom surface area of the cavity in Figs. 1 and 2,
respectively, and they are 39% and 55% to the upper
surface area of the ceramic sintered body in Figs. 3 and
4, respectively.
In the boat shown in Fig. 5, on the bottom surface
of the cavity, 50 grooves having a maximum length of 24
mm, a width of 1 mm and a depth of 0.15 mm are formed
with different lengths with a distance of 1 mm at an
angle of 90° to a current direction in an elliptic
pattern by mechanical processing. The area ratio
occupied by the pattern is 50% to the bottom surface area
of the cavity.
In the boat shown in Fig. 6, on the bottom surface
of the cavity, 44 grooves having a width of 1 mm and a
depth of 0.15 mm are formed with a distance of 1 mm at an
angle of 45° or 135°C to a current direction in the
dogleg pattern by mechanical processing. The area ratio
occupied by the pattern is 66% to the bottom surface area
of the cavity.
In the boat shown in Fig. 7, on the bottom surface
of the cavity, 50 grooves having a width of 1 mm and a
depth of 0.15 mm are formed with a distance of 1 mm at an
angle of 90° of 180° to a current direction in a lattice
pattern by mechanical processing. The area ratio
occupied by the pattern is 60% to the bottom surface area
of the cavity.
In the boat shown in Fig. 8, on the bottom surface
of the cavity, 20 grooves having a width of 1 mm and a
depth of 0.15 mm are formed in a radial pattern from the
boat center portion toward the boat edge by mechanical
processing. The area ratio occupied by the pattern is
61% to the bottom surface area of the cavity.
In the boat shown in Fig. 9, on the bottom surface
of the cavity and on the upper surface of the boat out of
the cavity, 60 grooves having a length of 20 mm, a width
of 1 mm and a depth of 0.15 mm are formed with a distance
of 1.5 mm at an angle of 90° to a current direction by
mechanical processing. The area ratio occupied by the
pattern is 77% to the bottom surface area of the cavity
and 67% to the upper surface area of the ceramic sintered
body.
In the boat shown in Fig. 10, on the upper surface
of the ceramic sintered body, 60 grooves having a width
of 1 mm, a depth of 0.15 mm (and a length of 27 mm at
each end portion, 23 mm at an intermediate portion and 19
mm at a center portion) are formed with a distance of 1.5
mm at an angle of 90° to a current direction, and in a
direction in parallel with the current direction, one
groove having a width of 1 mm, a depth of 0.15 mm and a
length of 130 mm is formed at each edge portion, and at
the inside thereof, a groove having a width of 1 mm, a
depth of 0.15 mm and a length of 65 mm is formed. The
area ratio occupied by the patter is 89% to the upper
surface area of the ceramic sintered body.
The method for evaporating a metal of the present
invention comprises supplying a metal such as an Al wire
rod so that it is in contact with part or all of the
groove portion on the boat of the present invention (in a
case where one groove is formed, it may be in contact
with a part of the groove), heating and carrying on
heating while the molten metal and the groove are in
contact. In such a manner, a metal deposited film is
formed on an object substance. As one example of vacuum
heating conditions, the degree of vacuum is preferably
from 1 X 10-1 to 1 X 10-3 Pa and the temperature is
preferably from 1,4 00 to 1,600°C.
EXAMPLES
EXAMPLE 1
A material powder mixture comprising 45 mass% of a
titanium diboride powder (average particle size: 12 µm) ,
30 mass% of a boron nitride powder (average particle
size: 0.7 µm) and 25 mass% of an aluminum nitride powder
(average particle size: 10 µm) was put in a die made of
graphite, followed by hot pressing at 1,750°C to produce
a ceramic sintered body (relative density: 94.5%,
diameter 200 mm x height 20 mm) . From this ceramic
sintered body, a rectangular column having a length of
150 mm, a width of 30 mm and a thickness of 10 mm was cut
out, and at a center portion on the upper surface thereof,
a cavity having a width of 26 mm, a depth of 1 mm and a
length of 120 mm was formed by mechanical processing. On
the bottom surface of the cavity, 50 grooves having a
width of 1 mm, a depth of 0.15 mm and a length of 20 mm
were formed with a distance of 1 mm at an angle of 90° to
a current direction by mechanical processing to produce a
boat. Its perspective schematic view is shown in Fig. 1.
EXAMPLE 2
A boat was produced in the same manner as in Example
1 except that the grooves had a width of 0.5 mm, a depth
of 0.1 mm and a length of 20 mm.
EXAMPLE 3
A boat was produced in the same manner as in Example
1 except that on the bottom surface of the cavity of the
boat, 35 grooves having a width of 1 mm, a depth of 0.15
mm and a length of 28 mm were formed with a distance of 1
mm at an angle of 45° to a current direction by
mechanical processing, and 35 grooves having the same
dimensions were formed at an angle of 135° to the current
direction, at right angles to the above grooves by
mechanical processing. Its perspective schematic view is
shown in Fig. 2.
EXAMPLE 4
A boat was produced in the same manner as in Example
1 except that on a center portion of the upper surface of
the rectangular column, one linear continuous groove
having a width of 1.5 mm, a depth of 0.2 mm and a length
of 645 mm was formed at an angle of 90° to a current
direction in a stripe pattern directly without forming a
cavity. Its perspective schematic view is shown in Fig.
3.
EXAMPLE 5
A boat was produced in the same manner as in Example
1 except that on a center portion of the upper surface of
the rectangular column, 50 grooves having a width of 1.0
mm, a depth of 0.15 mm and a length of 25 mm were formed
with a distance of 1 mm at an angle of 90° to a current
direction by mechanical processing, directly without
forming a cavity. Its perspective schematic view is
shown in Fig. 4.
EXAMPLE 6
A boat was produced in the same manner as in Example
1 except that the grooves were formed by sandblasting.
EXAMPLE 7
A boat was produced in the same manner as in Example
1 except that the grooves were formed by water jet and
that the boat was dried by a vacuum dryer.
COMPARATIVE EXAMPLE 1
A boat was produced in the same manner as in Example
1 except that no groove was formed on the rectangular
column.
COMPARATIVE EXAMPLE 2
A boat was produced in the same manner as in Example
1 except that the grooves had a width of 2.0 mm.
COMPARATIVE EXAMPLE 3
A boat was produced in the same manner as in Example
1 except that the grooves had a depth of 2.0 mm.
COMPARATIVE EXAMPLE 4
A boat was produced in the same manner as in Example
1 except that the grooves were formed with a distance of
3.0 mm.
In order to evaluate wettability of the boats in the
above Examples and Comparative Examples to a molten metal,
each end portion of the boat was connected to an
electrode by a clamp, and a voltage to be applied was set
so that the temperature at a center portion of the boat
would be 1,550°C. Then, a voltage was applied to the
boat for heating, an aluminum wire was supplied to the
groove portion at a rate of 6.5 g/min for 5 minutes in
vacuum at a degree of vacuum of 2 x 10-2 Pa and heating
was continued. 5 Minutes after initiation of aluminum
supply, the upper surface of the boat was photographed,
and the wet area was obtained from a comparison between
the glowing portion and the molten metal portion. Then,
the wet area was divided by the bottom surface area of
the cavity with respect to a boat having a cavity or by
the upper surface area of the ceramic sintered body with
respect to a boat having no cavity to calculate the wet
area ratio (%). The results are shown in Table 1.
Further, the boat life was evaluated. Namely, an
evaporative test was carried out at a temperature at a
boat center portion of 1,500°C in vacuum at a degree of
vacuum of 2 x 10-2 Pa while an aluminum wire was supplied
at a rate of 6.5 g/min for 4 0 minutes as a unit cycle,
and this operation was repeatedly carried out. The
number of repetition when the maximum erosion depth on a
surface of the boat on which aluminum was evaporated
reached 3 mm, was taken as the boat life. The results
are shown in Table 1.
TABLE 1
EXAMPLES 8 to 10
A boat was produced in the same manner as in Example
1 except that instead of the uniform grooves (totally 50
grooves) in Example 1, 50 grooves among which
predetermined number of grooves had different depths, as
identified in Table 2, were formed from one end to the
other end in a longitudinal direction of the boat so that
grooves at a center region would be deepest.
EXAMPLES 11 to 13
A boat was produced in the same manner as in Example
8, 9 or 10 except that no cavity was formed on the boat.
EXAMPLE 14
A boat was produced in the same manner as in Example
1 except that each of the 50 grooves had a groove depth
of 0.15 mm at a portion of 1/3 from the center in a
longitudinal direction of the groove and a groove depth
of 0.10 mm at each end portion.
With respect to the boats in Examples 8 to 14, in
the same manner as in Examples 1 to 7, the number of
repetition when the maximum erosion depth on a surface of
the boat on which aluminum was evaporated reached 3 mm,
was measured as the boat life. Further, the wettability
to a molten metal was measured in accordance with the
following method. The results are shown in Table 2.
TEST ON WETTABILITY TO MOLTEN METAL
Each end portion of the boat was connected to an
electrode by a clamp, and a voltage to be applied was
determined and set so that the temperature at a center
portion of the boat would be 1,600°C. Then, a voltage
was applied to the boat for heating, an aluminum wire was
supplied to the groove portion at a rate of 6.5 g/min for

5 minutes in vacuum at a degree of vacuum of 1 x 10-2 Pa,
and heating was continued. 5 Minutes after initiation of
aluminum supply, the upper surface of the boat was
photographed, and with respect to the expansion of a
molten metal portion, the width (mm) and the maximum
length (mm) at a center portion were measured. The
results are shown in Table 2.

INDUSTRIAL APPLICABILITY
The boat and the method for evaporating a metal of
the present invention are useful for deposition of
various metals on e.g. a film.
WE CLAIM:
1. A metal evaporation heating element having one or more grooves in a
direction not in parallel with a current direction, on an upper surface of a sintered body,
wherein the groove has a width of from 0.1 to 1.5 mm, a depth of from 0.03 to 1 mm and
a length of at least 1 mm, characterized in that
(i) the sintered body is a ceramic sintered body comprising titanium diboride (TiB2)
and/or zirconium diboride (ZrB2), and boron nitride (BN), and in that
(ii) the direction not in parallel with the current direction makes an angle of from 60
to 120° with the current direction.
2. The metal evaporation heating element as claimed in claim 1, which has at least
two grooves with a distance of not more than 2 mm.
3. The metal evaporation heating element as claimed in claim 1 or 2, wherein the
number of grooves is at least 10.
4. The metal evaporation heating element as claimed in claim 1, wherein the grooves
are crossed so as to form at least one intersection.
5. The metal evaporation heating element as claimed in any one of claims I to 4,
wherein the ceramic sintered body has a cavity, and the groove is formed on the bottom
surface of the cavity and/or on the upper surface of the ceramic sintered body.
6. The metal evaporation heating element as claimed in any one of claims 1 to 5,
wherein a pattern is drawn by a plurality of grooves on the bottom surface of the cavity
and/or on the upper surface of the ceramic sintered body.
7. The metal evaporation heating element as claimed in claim 6, wherein the area
ratio occupied by the pattern is at least 30% to the bottom surface area of the cavity with
respect to one having a cavity, or to the upper surface area of the ceramic sintered body
with respect to one having no cavity.
8. The metal evaporation heating element as claimed in claim 7, wherein the area
ratio occupied by the pattern is at least 50%.
9. The metal evaporation heating element as claimed in claim 7, wherein the area
ratio occupied by the pattern is at least 80%.
10. The metal evaporation heating element as claimed in any one of claims 1 to 9,
wherein in one groove, or between different grooves, a significant difference is provided
in the depth of the groove.
11. The metal evaporation heating element as claimed in claim 10, wherein the
significant difference in the depth of the groove is at least 10%.
12. The metal evaporation heating element as claimed in claim 10 or 11, wherein
among a plurality of grooves, the groove having the deepest portion is provided at a
center portion in the longitudinal direction of the ceramic sintered body or in the vicinity
thereof
13. The metal evaporation heating element as claimed in any one of claims 10 to 12,
wherein among the plurality of grooves, the groove having the shallowest portion is
provided at one end or each end in the longitudinal direction of the ceramic sintered body.
14. The metal evaporation heating element as claimed in any one of claims 10 to 13,
wherein {(depth of the deepest portion of the groove) - (depth of the shallowest portion
of the groove)} is at least 0.005 mm.
15. A method for evaporating a metal, such as herein described, by using the metal
evaporation heating element as claimed in any one of claims 1 to 14. and heating the
metal in vacuum, such that the metal is in contact with part or all of the groove(s) of the
metal evaporation heating element.

There is disclosed a metal evaporation heating element having one or more grooves in a direction not in parallel with a current direction, on an upper surface of a sintered body, wherein the groove has a width of from 0.l to 1.5 mm, a depth of from 0.03 to 1 mm and a length of at least 1 mm, characterized in that the sintered body is a ceramic sintered body comprising titanium diboride (TiB2) and/or zirconium diboride (ZrB2), and boron nitride (BN), and in that the direction not in parallel with the current direction makes an angle of from 60 to 120° with the current direction.

Documents:

01295-kolnp-2006 abstract.pdf

01295-kolnp-2006 assignment.pdf

01295-kolnp-2006 claims.pdf

01295-kolnp-2006 correspondence others-1.1.pdf

01295-kolnp-2006 correspondence others.pdf

01295-kolnp-2006 description (complete).pdf

01295-kolnp-2006 drawings.pdf

01295-kolnp-2006 form-1.pdf

01295-kolnp-2006 form-3-1.1.pdf

01295-kolnp-2006 form-3.pdf

01295-kolnp-2006 form-5.pdf

01295-kolnp-2006 international publication.pdf

01295-kolnp-2006 international search report.pdf

01295-kolnp-2006 pct form.pdf

01295-kolnp-2006 priority document.pdf

01295-kolnp-2006-correspondence-1.2.pdf

01295-kolnp-2006-form-18.pdf

1295-KOLNP-2006-ABSTRACT-1.1.pdf

1295-KOLNP-2006-AMENDED DOCUMENTS.pdf

1295-KOLNP-2006-CANCELLED DOCOMENT.pdf

1295-kolnp-2006-CLAIMS 1.1.pdf

1295-KOLNP-2006-CLAIMS-1.2.pdf

1295-KOLNP-2006-CORRESPONDENCE 1.1.pdf

1295-KOLNP-2006-DESCRIPTION COMPLETE-1.1.pdf

1295-KOLNP-2006-DRAWINGS-1.1.pdf

1295-KOLNP-2006-FORM 1-1.1.pdf

1295-KOLNP-2006-FORM 27.pdf

1295-kolnp-2006-FORM 3 1.1.pdf

1295-KOLNP-2006-FORM 3-1.1.pdf

1295-KOLNP-2006-FORM-27.pdf

1295-kolnp-2006-granted-abstract.pdf

1295-kolnp-2006-granted-assignment.pdf

1295-kolnp-2006-granted-claims.pdf

1295-kolnp-2006-granted-correspondence.pdf

1295-kolnp-2006-granted-description (complete).pdf

1295-kolnp-2006-granted-drawings.pdf

1295-kolnp-2006-granted-examination report.pdf

1295-kolnp-2006-granted-form 1.pdf

1295-kolnp-2006-granted-form 18.pdf

1295-kolnp-2006-granted-form 3.pdf

1295-kolnp-2006-granted-form 5.pdf

1295-kolnp-2006-granted-gpa.pdf

1295-kolnp-2006-granted-reply to examination report.pdf

1295-kolnp-2006-granted-specification.pdf

1295-kolnp-2006-PETITION UNDER RULE 137.pdf

1295-KOLNP-2006-PETITION UNDER RULE.pdf

1295-KOLNP-2006-REPLY TO EXAMINATION REPORT-1.1.pdf

1295-KOLNP-2006-REPLY TO EXAMINATION REPORT-1.2.pdf

1295-kolnp-2006-REPLY TO EXAMINATION REPORT.pdf

abstract-01295-kolnp-2006.jpg


Patent Number 235704
Indian Patent Application Number 1295/KOLNP/2006
PG Journal Number 33/2009
Publication Date 14-Aug-2009
Grant Date 11-Aug-2009
Date of Filing 16-May-2006
Name of Patentee DENKI KAGAKU KOGYO KABUSHIKI KAISHA
Applicant Address 1-1, NIHONBASHI-MUROMACHI 2-CHOME, CHUO-KU, TOKYO
Inventors:
# Inventor's Name Inventor's Address
1 IKARASHI, KOUKI C/O DENKI KAGAKU KOGYO KABUSHIKI KAISHA OMUTA KOJO, 1, SHINKAI-MACHI, OMUTA-SHI, FUKUOKA 8368510
2 MIYAI, AKIRA C/O DENKI KAGAKU KOGYO KABUSHIKI KAISHA OMUTA KOJO, 1, SHINKAI-MACHI, OMUTA-SHI, FUKUOKA 8368510
3 WATANABE,SHOUJIRO C/O DENKI KAGAKU KOGYO KABUSHIKI KAISHA OMUTA KOJO, 1, SHINKAI-MACHI, OMUTA-SHI, FUKUOKA 8368510
4 SUSAKI, JUNICHI C/O DENKI KAGAKU KOGYO KABUSHIKI KAISHA OMUTA KOJO, 1, SHINKAI-MACHI, OMUTA-SHI, FUKUOKA 8368510
5 IWAMOTO, KENTARO C/O DENKI KAGAKU KOGYO KABUSHIKI KAISHA OMUTA KOJO, 1, SHINKAI-MACHI, OMUTA-SHI, FUKUOKA 8368510
PCT International Classification Number C23C 14/24
PCT International Application Number PCT/JP2004/017023
PCT International Filing date 2004-11-16
PCT Conventions:
# PCT Application Number Date of Convention Priority Country
1 2004-008217 2004-01-15 Japan
2 2003-390344 2003-11-20 Japan
3 PCT/JP2004/010568 2004-07-16 Japan