Method of molding high-viscosity materials

This invention provides a method of molding which can feed the high-viscosity material quickly and accurately as well as with good operability. For achieving quick heating and cooling cycles in a mold, the mold is constructed from a mold material having superior heat-conductivity in such a way that the high-viscosity material can be heated and cooled from outside of the mold. Thereby, this invention comprises: PA1 a step for preparing a mold fabricated with high orientation graphite material, PA1 a step for feeding high-viscosity material into the recess portion for molding inside said mold in the non-molten state, PA1 a step for heating and melting the high-viscosity material in the recess portion via said mold from the outside, and PA1 a step for cooling the molten high-viscosity material via said mold and molding it into a desired shape.

BACKGROUND OF THE INVENTION 
This invention relates to a method for molding high-viscosity materials. 
For a specific example of a technique to use high-viscosity material by 
molding, a technique for preparing a bump electrode for semiconductor ICs 
is known. The metallic material to be molded into a bump electrode is 
brought to a high-viscosity mixture liquid state together with a binder, 
and the mixture is discharged in a specified amount from a nozzle, and an 
electrode of a specified profile is molded on a substrate. This method 
provides features of simpler operation and reduced processes as compared 
to the technique for preparing bump electrodes using photolithographic or 
etching techniques which have been generally practiced hitherto. 
On the other hand, a process for applying high-viscosity adhesive on to the 
substrate in a form of spots for the purpose of mold bonding, etc. is 
practiced. In this case, using the similar nozzle as described above, a 
high-viscosity adhesive is formed into a specified spot. 
In the fabrication technique for the bump electrode as specified above, the 
molding profile of the high-viscosity material is extremely important. 
Moldings with a specified profile and uniform size must be produced. 
However, the material liquid with high viscosity provides poor fluidity and 
it is difficult to accurately control the discharge rate from the nozzle. 
Consequently, variations tend to occur in the profile and size of the 
molded high-viscosity material. In the case of the above-mentioned bump 
electrode, there is a case in which as many as tens of to more than one 
hundred pieces of bump electrodes are prepared on one IC substrate, and it 
is extremely troublesome to change places for each of many bump electrodes 
and discharge high-viscosity material liquid from the nozzle to form bump 
electrodes one by one. In particular, the high-viscosity material liquid 
with poor fluidity does not begin discharging immediately even when the 
gate is opened or pressure is applied to discharge the liquid from the 
nozzle, and conversely, when discharging the liquid from the nozzle is 
planned to be ended, discharge is unable to be immediately stopped. 
Consequently, long molding time is required for one operation cycle, and 
operability becomes extremely degraded when a large number of moldings are 
repeatedly produced as described above. Improvement in the nozzle profile 
and construction has been proposed as a technique for solving the above 
problems, but satisfactory solution has not yet been obtained, leaving a 
problem of increased complication in the equipment construction such as 
nozzles, etc. 
SUMMARY OF THE INVENTION 
It is an object of this invention to provide a molding process which can 
quickly and accurately feed the high-viscosity material as described above 
to a recess portion for molding and can produce moldings with accurate 
profile and size at the accurate position with good operability when said 
high-viscosity material is molded into a specified profile. In order to 
achieve the above-mentioned object, taking a bump molding machine as an 
example, the bump material must be fed in a non-molten state free of high 
viscosity, but for this purpose, the heating and cooling cycles in which 
the high-viscosity material in the non-molten state is heated and melted 
in the recess portion for molding and, then, cooled must quickly take 
place. 
Therefore, this invention has been completed with eyes placed on the fact 
that the mold itself must provide excellent thermal conductivity and must 
be constructed to enable heating and cooling of the recess portion for 
molding via mold material from outside of the mold in order to achieve the 
quick heating and cooling cycle inside the mold, and this invention method 
of molding a high-viscosity material having a high melt viscosity, which 
comprises the steps of: 
preparing a mold fabricated with high-orientation graphite materials; 
feeding the high-viscosity material into a molding recess portion of said 
mold in a non-molten state, 
heating the high-viscosity material existing in said recess portion via 
said mold from outside to melt said high-viscosity material; and 
cooling the molten high-viscosity material in said recess portion via said 
mold from outside to mold said molten high-viscosity material into a 
desired shape. 
In this invention, in order to implement the above molding process, said 
mold must quickly and accurately transfer heat from the outside of the 
mold to the recess portion for molding, the high-orientation graphite 
material composing said mold shall be a laminate with the high-orientation 
graphite sheets stacked, the recess portion for molding shall be molded on 
one side of said laminates sheets whose end faces are arranged in a line, 
and the graphite crystal should be oriented to the opposite side. 
In addition, in order to uniformly heat and cool the recess portion for 
molding of said mold, to the side opposite to the other side on which the 
end faces of the first graphite sheet laminate with high orientation 
composing said mold are arranged in a line, it is preferable to join a 
laminate in which the second graphite sheets are stacked in such a manner 
that the orientations intersect orthogonally, and to heat and cool the 
recess portion for molding molded on the end face from said second 
laminate via the first laminate. 
The laminate of said sheet can be fabricated by using the process described 
in Japanese Non-examined Patent Publication No. Hei 4-21508, laminating 
specific polymer film, and eventually heat-treating at temperatures higher 
than 2400.degree. C., while heat-treatment at the temperature range of 
2000.degree. C. or higher is being carried out in inert gas, but it is 
preferable to integrally fix the laminates by bundling them with 
heat-resistant band. 
The said polymer film contains a filler, and is chosen from a group 
comprising polyoxadiazole 200 .mu.m or thinner, polybenzothiazole, 
polybenzobisthiazole, polybenzoxazole, polybenzobisoxazole, 
poly(pyromellitoimide), poly(m-phenylene isophthalamide), poly(phenylene 
beozobisimidazole), polythiazole, and polyparaphenylene vinylene, but in 
particular, aromatic polyimide film such as poly pyromellitoimide is 
preferable. 
For feeding high-viscosity material to the recess portion for molding in 
said mold, it is preferable to provide a high-viscosity material feeding 
means for feeding high-viscosity material to said recess portion for 
molding to said mold. In order to heat and melt the high-viscosity 
material in the recess portion for molding from outside via said mold and 
to cool the molten high-viscosity material, it is preferable to provide a 
heating and cooling means for heating and cooling selectively the inside 
of the recess portion for molding to the outer surface of the recess 
portion for molding for the mold. 
When molding is carried out using the material in the powder form, it is 
preferable to prepare the high-viscosity material which is mixed with the 
binder for printing in a paste form, and metallic powder, bump material 
powder, dielectric material powder, insulation material powder, optical 
parts material powder, and other various powders are selected in accord 
with applications for molding. The binder for printing vaporizes and 
disappears during heating at the recess portion for molding. The means for 
feeding this paste-form high-viscosity material is preferably constructed 
with a screen printing plate with a powder passage located at the position 
corresponding to said recess portion for molding arranged at the upper 
part of the surface with the recess portion for molding of said mold and a 
screen printing machine with a squeegee which pushes to move said powder 
fed to the top surface of the screen printing plate along the screen 
printing plate. 
When said high-viscosity material is a wires for wire bonding, etc., the 
means for feeding high-viscosity material shall be located at the upper 
part of the surface with the recess portion for molding of the mold and 
shall be constructed as a wires feeder for feeding the top end of the 
wires to the recess portion for molding. 
On the other hand, for the heating and cooling means, it is preferable to 
have a heating body and a cooling body free to selectively come in contact 
with the opposite surface of the mold. 
Because the process according to this invention comprises a mold for 
high-viscosity material made from high-orientation graphite and achieves 
excellent thermal conductivity, heating of the high-viscosity material 
quickly and efficiently takes place via the mold when the high-viscosity 
material is fed to the recess portion for molding and heated to melt. In 
the event of cooling the product of the high-viscosity material heated, 
melted, and molded, it can be quickly and efficiently cooled via the mold. 
Consequently, it is possible to feed powders or wires to the recess 
portion for molding, and to produce a specified molding using the quick 
heating and cooling cycle. Because this high-orientation graphite also 
provides excellent heat resistance, it can be smoothly applied to 
high-viscosity material which must be melted at high temperature. 
If the high-orientation graphite is oriented from the surface with the 
recess portion for molding to the opposite surface, since high-orientation 
graphite provides particularly large thermal conductivity in the direction 
along the orientation, the powder or molding in the recess portion for 
molding on the surface can be quickly and efficiently heated and cooled by 
heating or cooling from the external surface opposite to the recess 
portion for molding inside the mold. 
The high-orientation graphite is generally manufactured in a thin sheet 
state. If these high-orientation graphite sheets are laminated to form a 
laminate, a mold with sufficient thickness can be easily constructed. The 
laminate of high-orientation graphite oriented in the plane direction 
achieves the condition in which it is successfully oriented in the plane 
direction of the sheet as a whole. If the recess portion for molding is 
molded on the surface in which sheet end faces are arranged in line, a 
mold with extremely good orientation with high-orientation graphite 
orientation aligned uniformly from the surface equipped with the recess 
portion for molding to the opposite surface is achieved, and the thermal 
conductivity from the surface to the opposite surface is improved. 
If the laminates of the high-orientation graphite sheets are integrally 
fixed by bundling with a heat-resistant band, a mold can be easily 
fabricated without bonding the sheets composing the laminates. Because the 
mold is heated to high temperature or rapidly heated and cooled 
repeatedly, the integrity of sheets may be degraded by such means as 
bonding, but bundling with a heat-resistant band can satisfactorily stand 
heating to high temperature or rapid heating or cooling. 
Providing both means for feeding high-viscosity material and means for 
heating and cooling to the mold enables quick execution of a series of 
operating processes from feeding of high-viscosity material to the recess 
portion for molding, heating and melting as well as molding of 
high-viscosity material, and to cooling. 
When the molding material is powder, if the high-viscosity material is 
prepared by mixing the powder and a printing binder which vaporizes by 
heating, easy handling as well as easy heating, melting, and molding can 
be achieved. In this event, if the means for feeding high-viscosity 
material is equipped with a screen printing machine with a screen printing 
plate and squeegee, a required volume of powder can be reliably and 
efficiently fed to the recess portion of the mold. Even when a large 
number of recess portions for molding are provided in the mold, it is 
possible to uniformly feed the powder to a large number of recess portions 
for molding simultaneously. 
If the high-viscosity material is in the form of wires which can be heated 
and melted, it is hard to scatter and easy to be stored and transported. 
In this event, if the means for feeding high-viscosity material feeds the 
top end of the wire pieces to the recess portion for molding, it is 
possible to heat and melt and form only the required volume of wire piece 
in the recess portion for molding. There is no fear of high-viscosity 
material leaking outside the recess portion for molding. The construction 
of the equipment for feeding wire pieces can be simplified. 
If the means for heating and cooling is equipped with a heating element and 
cooling element which selectively come in contact on the opposite surface 
of the mold, it is not necessary to equip a complicated heating mechanism 
or cooling mechanism inside the mold composed of high-orientation 
graphite, and it is easy to produce moldings. Bringing the heating element 
in contact with the mold quickly begins heating and separating the heating 
element from the mold and bringing the cooling element in contact quickly 
begins cooling, enabling quick change-over from heating to cooling and 
vice versa and improving the operation efficiency. 
Because the process for molding high-viscosity material according to this 
invention feeds high-viscosity material in the form of powder, powder 
mixed paste, or non-molten condition of wire pieces to the recess portion 
for molding, material can be fed to the mold far simply as compared to the 
case in which molten high-viscosity material is fed. It is also possible 
to accurately set the feed rate of the high-viscosity material. If the 
heating element is brought in contact with the recess portion for molding 
of the mold at the opposite surface, the powder fed to the recess portion 
for molding on the surface can be rapidly heated and melted via the mold 
composed with high-orientation graphite with excellent thermal 
conductivity and molded in accordance with the profile of the recess 
portion for molding. If the cooling element is brought into contact with 
the mold in place of the heating element, moldings in the recess portion 
for molding are rapidly cooled and the condition that can maintain a 
specified molding profile is achieved. The cooled moldings can be taken 
out from the mold and freely used. 
If the high-viscosity material is a powder mixture of metal and a binder, 
compacts for producing metal sintered products and compacts to be used for 
bump electrodes can be simply and efficiently manufactured. If the 
high-viscosity material is bump material, fabrication of bump electrodes 
can be easily and efficiently carried out. If the high-viscosity material 
is dielectric material or insulating material, fabrication of dielectric 
members and insulating members which are utilized for various electronic 
equipment can be easily and efficiently carried out. If the high-viscosity 
material is optical parts material, fabrication of optical parts utilized 
for various optical equipment can be easily and efficiently carried out. 
If the high-viscosity material is wire pieces for wire bonding, 
fabrication of wire bonding construction utilized for various electronic 
equipment can be simply and efficiently carried out.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
Referring now to the drawings, the present invention will be described in 
detail hereinafter. 
The molding machine shown in FIG. 1 is a molding machine used for 
fabricating bump electrodes on the IC substrate. It is equipped with a 
mold 10, heating element 21, and cooling element 30. 
The mold 10 comprises a rectangular laminate piece 12 to which strip-form 
high-orientation graphite sheets 12a are stacked in many pieces in the 
through-thickness direction and a heat-resistant band 14 arranged on the 
outer circumference of the laminate piece 12 along the laminate direction 
of the sheet 12a. 
Graphite is carbon crystalline, whose crystal forms a layer structure. It 
is the high orientation graphite in which this carbon crystalline is 
arranged in a specified orientation. To manufacture high-orientation 
graphite, for example, specific polymer film as described above can be 
obtained by being fired under the following conditions. Firing polymer 
film with a plurality of the film stacked can produce sheet-form or 
block-form high-orientation graphite. For the high-orientation graphite 
sheet 12a, the high-orientation graphite film itself comprising polymer 
film as above may be used or a plurality of thin high-orientation graphite 
films which are stacked and fired to produce a sheet with a specified 
thickness may be used. The sheet 12a about 5-200 .mu.m thick is used. 
Manufacturing Example 1 
Poly pyromellitoimide (available from Du Pont as CAPTON H FILM) 25 .mu.m 
thick were stacked in 200 pieces and set to a graphite jig and heated to 
1400.degree. C. at a rate of 10.degree. C./min in argon gas. During this 
period, to the specimen, pressure of 100 g/cm.sup.2 jig weight was 
designed to be applied. Then, after 1400.degree. C. was reached, the 
specimen was heated to 1600.degree. C. with 30 kg/cm.sup.2 pressure 
applied while keeping the same heating rate. Thereafter, pressure was 
reduced to enable only the jig pressure to be applied, and the specimen 
was heated to 2700.degree. C. Then, pressure was increased to 300 
kg/cm.sup.2 and temperature was heated to 3000.degree. C. to complete heat 
treatment, and graphite block was obtained. 
Manufacturing Example 2 
Poly pyromellitoimide (available from Du Pont as CAPTON H FILM) 25 .mu.m 
thick containing 5% by weight of calcium hydrogenphosphate was heated to 
1000.degree. C. at a rate of 3.degree. C./min in nitrogen gas using an 
LTF-S type electric furnace of Sankyo Denro Company and held for 1 hour at 
1000.degree. C. for pre-heat treatment. Then, the obtained carbonized 
sheet was set inside a graphite cylinder so that the sheet could be freely 
stretched or shrunk, and was heated to 2800.degree. C. at a rate of 
5.degree. C./min together with the graphite cylinder using an ultra-high 
temperature furnace 46-5 type of Shinsei Denro Company. Heating was 
carried out at normal pressure in argon atmosphere. The obtained sheet was 
passed between two stainless rollers (available from Kumagaya Riken Kogyo) 
to undergo rolling treatment. A sheet with 630 kgf/cm.sup.2 tensile 
strength and 860 kcal/m.multidot.h.multidot..degree.C. thermal 
conductivity was obtained. 
The heat-resistant band 14 was made of high-orientation graphite sheet same 
as that of laminate 12, and was wrapped around the outer circumference of 
the laminate 12 to firmly bind sheets 12a composing the laminate 12, 
integrate, and fix. Edges of the heat-resistant band 14 are stacked and 
affixed or mechanically bonded. 
On the top surface of the mold 10 on which end faces of sheets 12a are 
aligned, a plurality of recess portions 16 for molding are provided along 
the outer circumference. Electric discharge machining is used for 
providing the recess portion for molding 16 on the surface of the mold 10 
comprising high-orientation graphite sheets 12a. 
The recess portion for molding 16 is a flat round column with a spherical 
bottom. The profile and arrangement of the recess portion for molding 16 
are set in conformity to the profile and arrangement of the bump electrode 
to be fabricated. 
The heating element 20 comprises metal and others with large heat capacity, 
has an upper surface profile in contact with the bottom surface of the 
mold 10, and forms a rectangular shape as a whole. The cooling element 30 
is composed with the material same as that of heating element 20 and also 
has a same shape. 
The heating element 20 is mounted movably between the position in contact 
with the bottom surface of the mold 10 and a heating device (not 
illustrated) such as a heating furnace or a heater for heating the heating 
element 20 at the position away from the mold 10. The cooling element 30 
is mounted movably between the position in contact with the bottom surface 
of the mold 10 and the position away from the mold 10. To the cooling 
element 30, no special cooling device is equipped but it should be kept 
low with respect to the heating element 20 by allowing the cooling element 
to cool at room temperature. 
In order to enable the heating element 20 and the cooling element 30 to 
uniformly heat and easily cool, respectively, a heating element 200 or 
heating and cooling element 300 with high orientation in the plane 
direction shown in FIG. 8 or FIG. 9 may be used on the heating and cooling 
sides of the mold 10. 
In the case of FIG. 8, the heating element comprises bonding the laminate 
200 via bonding graphite sheet 201 (which can be fabricated by the process 
disclosed in Japanese Non-examined Patent Publication No. Hei 2-103478 
corresponding to U.S. Pat. No. 5,091,025), which comprises the second 
graphite sheets stacked with the orientation intersecting orthogonally on 
the side opposite to the other side, wherein the end faces of the mold 
100, the first graphite sheet laminate of high orientation which forms the 
recess portion for molding 16 are arranged in parallel, irradiating the 
second laminate 200 with laser beam from YAG or CO.sub.2 laser beam device 
202 which reciprocates horizontally, receiving heat that spreads in the 
plane direction of the second laminate 200 via the first laminate 100, and 
heating the recess portion for molding 16 formed on its end face. Because 
the second laminate 200 has high orientation in the plane direction, the 
second laminate 200 provides a property to function as a uniform heating 
source when there is 1 mm or more thickness even when the laser beam 
irradiates the center. 
On the other hand, in FIG. 9, in place of the laser beam device used in 
FIG. 8, a Peltier element 300 is used for a heating and cooling element, 
and the Peltier element 300 may be used as a uniform heating and cooling 
source for the first laminate 100 using the high orientation of the second 
laminate 200 in the plane direction by mounting the Peltier element 300 to 
part of both ends of the second laminate 200. 
Now, the description will be made on the molding method using the molding 
machine of the above-mentioned construction. 
As shown in FIG. 2, a screen printing machine 40 is arranged above the mold 
10. 
The screen printing machine 40 is a machine used for so-called silk screen 
printing. The screen printing machine 40 has a screen printing plate 42 
whose periphery is supported with a frame. The screen printing plate 42 
comprises a metal or synthetic resin plate or mesh and is provided with 
holes for allowing the printing material to pass only at the portions to 
be printed. Under this embodiment, a round powder passage hole 46 nearly 
same as the plane profile of the recess portion for molding 16 is provided 
on the screen printing plate 42 at the portion above the recess portion 
for molding 16 of the mold 10. 
On the top surface of the screen printing plate 42, powder paste 50 of 
high-viscosity material is fed, and a squeegee 44 in the form of knife 
with the bottom end pointed moves along the top surface of the screen 
printing plate 42. 
The powder paste 50 is the powder mixing metallic powders to be a bump 
electrode with a binder comprising synthetic resin which exhibits a 
function to integrate metal powders at the time of molding. 
The powder paste 50 which drops from the powder passage hole 46 as the 
squeegee 44 moves collects inside each of the recess portions for molding 
16. The powder paste 50 can be fed to the amount near the top edge or 
slightly exceeding the top edge of the recess portion for molding 16. 
After the powder paste 50 is fed to the recess portion for molding 16, the 
heating element 20 heated to high temperatures about 300.degree. C. is 
brought in contact with the bottom surface of the mold 10 as shown in FIG. 
1. Then, heat is transferred from the heating element 20 to the powder 
paste 50 in the recess portion for molding 16 via the mold 10. The heated 
powder paste 50 melts and is formed in accordance with the profile of the 
recess portion for molding 16. If a binder for printing is used for the 
binder, the binder can be vaporized and allowed to disappear at the time 
of heating. 
As shown in FIG. 3A, the heated and melted powder 50 is formed in a sphere 
along the bottom profile of the recess portion for molding 16 by the 
action such as the surface tension of itself and the molding 52 is formed. 
When the powder 50 is heated and melted to produce the molding 52, the 
heating element 20 is removed from the bottom surface of the mold 10 and 
the cooling element 30 held to temperatures about 20.degree. C. is brought 
in contact with the bottom surface of the mold 10. The molding 52 is 
cooled via the mold 10. When the molding is cooled to the degree that 
enables easy handling of the molding 52, the cooling element 30 is 
separated from the mold 10 and cooling is completed. The molding 52 can be 
removed from the recess portion for molding 16. 
Under this embodiment, as shown in FIG. 3B, the molding 52 is directly 
moved to the substrate 60 on which the bump electrode is formed. That is, 
on the bottom surface of the substrate 60, protrusion 62 for supporting 
the electrode is provided. This protrusion 62 may be a terminal of IC 
substrate or part of wiring member. The protrusion 62 is brought closer to 
the mold 10 on the substrate 60 and pierced into the molding 52. In this 
event, the molding 52 is completely cooled and is in the state easy to 
deform before solidification. Raising the protrusion 62 pierced into the 
molding 52 together with the substrate 60 removes the molding 52 from the 
recess portion for molding 16 with the molding 52 pierced at the top end 
of the protrusion 62 and moves the molding to the substrate 60. If the 
molding 52 moved to the substrate 60 further cools and solidifies, the 
molding 52 is fixed while it is pierced by the protrusion 62. 
In this way, if the molding 52 is directly moved from the mold 10 to the 
substrate 60, it is no longer necessary to carry out operation for 
removing the molding 52 from the mold 10 and mounting the removed molding 
52 to a specified position of the substrate 60 separately, and fabrication 
of the bump electrode can be carried out remarkably efficiently. Moreover, 
since no other apparatus or member comes in contact with the molding 52, 
the profile of the bump electrode fabricated becomes exactly same profile 
of the molding 52 obtained at the time of molding. The entry of any 
foreign matter into the molding 52 can also be prevented. 
The profile of the recess portion for molding 16 provided to the mold 10 
may be semi-circular as shown in FIG. 4A in addition to the columnar 
profile mentioned above. In the case of the semi-circular recess portion 
for molding 16, as shown in FIG. 4B, the powder 50 is fed so that the 
powder rises on the surface of the mold 10 exceeding the top end of the 
recess portion for molding 16. The powder 50 may be allowed to stick out 
from the outside of the recess portion for molding 16. 
As shown in FIG. 4, when the powder 50 is heated and melted, the molding 52 
is formed in the similar manner in the case of above embodiments. Because 
the powder collects in a spherical shape by the action such as surface 
tension as the powder 50 is heated and melted and the powder 50 is 
integrated into the molding 52. 
Under this embodiment, because the molding 52 protrudes above the recess 
portion for molding 16, it is easy to carry out said operation for 
transferring the molding to the substrate 60. Even if there is no 
protrusion 62 on the substrate 60, it is possible to transfer the molding 
52 to the substrate 60 by bringing the flat surface of the substrate 60 in 
contact with the top end of the spherical molding 52 protruding from the 
surface of the mold 10 and affixing the molding 52 to the substrate 60. 
Then, as shown in FIG. 5A-5C, it is possible to use a conical recess 
portion for molding 16. In this event, the powder 50 fed protruding from 
the outside of the recess portion for molding 16 is integrated in a 
spherical form by surface tension and other action when the powder is 
heated and melted and a spherical molding 52 internally in contact with 
the conical recess portion for molding 16 is obtained. 
Under this embodiment, depending on the amount of the powder 50 fed to the 
recess portion for molding 16, the sphere diameter of the molding 52 
formed varies. it is possible to easily produce the molding 52 in a wide 
variety of spheres with one type of conical recess portion for molding 16. 
As shown in FIG. 6, wire pieces 54 comprising high-viscosity wire bonding 
material shaped in the thin wire form may be used. 
As shown in FIG. 6A, the wire piece 54 is arranged above the recess portion 
for molding 16 of the mold 10. The wire piece 54 is handled by using a 
handling device of wire pieces similar to the general wire bonding 
equipment and the like. 
As shown in FIG. 6B, the top end of the wire piece 54 is pressed against 
the recess portion for molding 16 of the heated mold 10. The wire piece 54 
is gradually heated and melted from the top end. Continuously pressing the 
wire piece 54 against the recess portion for molding 16 heats and melts 
the wire piece 54 successively and the high-viscosity material in the 
heated and molten state collects in the recess portion for molding 16. 
As shown in FIG. 6C, when a required amount of high-viscosity material in 
the form of wire piece 16 is fed into the recess portion for molding 16, 
the wire piece 54 is kept away from the recess portion for molding 16. The 
high-viscosity material in the heated and molten state which collects in 
the recess portion for molding 16 is spontaneously formed into a spherical 
form as in the case of above embodiments and the spherical molding 56 is 
obtained. The subsequent cooling process takes place in the similar manner 
as in the case of above embodiments. 
Embodiments where vacuum suction is carried out! 
As shown in FIG. 7, the basic process is same as that in the embodiments 
shown in FIG. 4, but in this embodiment, as shown in FIG. 7A, after the 
high-viscosity powder 50 is fed into the recess portion for molding 16 of 
the mold 10, the mold 10 is charged into the vacuum suction equipment 80 
as shown in FIG. 7B. In the vacuum suction equipment 80, the mold 10 is 
heated to discharge volatile constituents such as the binder contained in 
the powder 50 and at the same time gas inside the vacuum suction equipment 
80 is vacuum-sucked and the volatile constituents discharged from the 
powder 50 are removed outside. 
As shown in FIG. 7C, the powder 50 with the volatile constituents removed 
is heated and melted and formed in accord with the profile of the recess 
portion for molding 16, and the molding 52 nearly in the form of lens can 
be obtained. 
Under this embodiment, the volatile constituents contained in the 
high-viscosity material can be quickly and efficiently removed by vacuum 
sucking and the operability of the molding process can be improved and at 
the same time, the molding 52 obtained achieves the high quality with less 
volatile constituent residues. 
Other Embodiments! 
(1) The mold 10 may be composed with the laminate 12 with said 
high-orientation graphite sheets 12a stacked or may be composed using 
block-form high-orientation graphite. 
(2) The recess portion for molding 16 may be machined not only by said 
electric discharge machining but other machining techniques such as 
etching and laser machining. 
(3) The heat-resistant band 14 may be fabricated with materials other than 
high-orientation graphite if it provides thermal resistance which can 
stand heating in the molding process and mechanical strength that can bind 
the high-orientation graphite sheets 12a. If the heating temperature at 
the time of molding exceeds 1200.degree. C., ceramic heat-insulating cloth 
or high-orientation graphite sheet is preferable. When the heating 
temperature during molding is low, it is possible to use metal bands. 
(4) For the high-viscosity material, any optional material can be used if 
it is said bump electrode material such as various metals, synthetic 
resins, ceramics, and other materials containing organic or inorganic 
substances. It is preferable to apply to the material which has hitherto 
be molded in the high-viscosity liquid state. Specifically, electrode 
materials, dielectric materials, insulation materials, adhesives, and the 
like used for various electronic parts are used. It is also possible to 
use sinter materials for sinter-manufacturing various mechanical parts. 
Optical parts materials such as glass can also be used. To use the 
high-viscosity material in the form of powder or wire pieces, the material 
which can be processed in each form should be used. 
(5) To heat and melt the high-viscosity material for molding, the material 
is heated to the heating temperature that is suited for relevant 
high-viscosity materials. If the heating temperature is comparatively low, 
the high-viscosity material can be molded in the atmosphere but when the 
heating temperature exceeds as high as 800.degree. C., it is preferable 
for molding in inert gas. 
(6) To produce the molding 52 from high-viscosity material powders 50 or 
wire pieces 54, a means for heating the mold 10 is essential but when it 
is cooled only by air cooling, a special cooling means is not always 
required. However, to improve the operability by quickly cooling the 
molding, the cooling means such as the cooling element 30 described above 
is effective. 
(7) This invention is not only applied to molding of said bump electrode 
and spot-form adhesives but also to molding of sinter material for 
sinter-manufacturing various mechanical parts. It can also be applied to 
melt-forming of optical parts such as glass. 
FIG. 10 compares the conventional process with the case where the process 
according to this invention is applied in mounting. That is, in the 
conventional process, bonding parts are formed by bonding wire and gold 
ball and bonded to the ICs conveyed. If there are N pieces of bonding 
places, bonding is repeated N times. Then, soldering/silver paste is 
printed and the relevant IC parts are surface-mounted on the circuit 
substrate separately conveyed. Then, after the reflow/laser reflow is 
provided to the circuit substrate with IC parts mounted, final inspection 
is carried out on the mounting. 
According to this invention, the printing paste formed by mixing the powder 
for high-viscosity material for bonding parts with the printing binder is 
fed to the recess portion of the mold according to this invention by 
screen printing, and is heated and melted and then cooled for molding. By 
one molding, stereoscopic bonding parts are manufactured and arranged in a 
line inside the mold. Consequently, it is possible to convey specified ICs 
to the mold equipped with this aligned bonding parts and allow the bonding 
parts to be transferred in a batch and bonded. Circuit substrates is 
surface-mounted in the similar manner to that carried out in the 
conventional manner. 
FIG. 11 compares the molding methods in molding optical parts when the 
conventional method and the method according to this invention are 
applied. That is, conventionally, for the lens material, ball lens is cut 
from a lens rod, and is ground into a specified profile, made into a 
specified profile by a hot press, and is further ground for final 
inspection. 
As against this, when this invention is applied, lens material glass frits 
are pulverized to super fine powders and mixed with acrylic low molecular 
weight compound (for example, green sheet binder for ceramics) as a 
printing binder to produce a paste. This paste is injected into the recess 
portion for molding of the mold by the printing method according to this 
invention. Then, with the heat cycle meticulously controlled by the laser 
beam, the paste is heated to high temperatures of about 16000.degree.C. 
and melted to allow the binder component to vaporize, and is subjected to 
press molding. According to the process of this invention, the process for 
cutting and grinding the lens ball is not required, achieving a remarkably 
easy molding process.