JP3184293B2 - Sputtering equipment for powder coating - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sputtering apparatus used for coating a raw material powder charged in a cylindrical drum.

[0002]

2. Description of the Related Art When a metal film, an inorganic film or the like is formed on powder particles of metals, ceramics, plastics, etc., characteristics different from those of the original powder particles can be given. For example, when tungsten particles, diamond particles, and the like are coated with copper, sinterability is improved, and a sintered body having excellent thermal conductivity is obtained. The copper-coated powder is also used as a filler for electromagnetic shielding.

As means for coating the powder particles, there are known a method of performing electroplating or electroless plating by suspending the powder, and a method of forming a predetermined film on the powder in a fluidized state by sputtering. ing.
The present inventors also introduced a sputtering apparatus using a rotating drum as an apparatus for coating powder by sputtering in JP-A-2-153068.

[0004] In this powder coating apparatus, as shown in FIG. 1, a reduced-pressure heat treatment chamber 1 containing powder particles P before coating is connected to a rotary drum 2 having a sputtering source 3 built therein.

[0005] The powder particles P are accommodated in a container 1b provided with a heating coil 1a, and are supplied to the inside of the rotary drum 2 via a supply conduit 1e by a screw feeder 1d driven by a motor 1c. The supply conduit 1e is supported by a bearing 2f provided on one end face of the rotary drum 2.
A gas introduction pipe 1g is provided concentrically with the supply pipe 1e so as to feed the inert gas into the inside of the rotary drum 2.

[0006] The rotary drum 2 is supported by a driving roll 2a and a driven roll 2b. The drive roll 2a receives power from the motor 2c and rotates the rotary drum 2 around a horizontal axis. The sputtering source 3 is rotated by an arm 3b hermetically supported by a bearing 3a at an end surface (right side in FIG. 2) opposite to the end surface into which the supply conduit 1e is inserted.
And a target plate 3c slightly shorter than the axial length of the rotary drum 2 is disposed obliquely downward.

The powder particles P supplied to the axial end of the rotary drum 2 from the supply conduit 1 e are distributed over the entire length of the drum shaft as the rotary drum 2 rotates, and flow on the inner bottom surface of the rotary drum 2. The coating material is beaten out of the target plate 3c by the impact of the plasma of Ar or the like, flies in the rotary drum 2 and adheres to the powder particles P in a flowing state. When a predetermined coating layer is formed, the rotating drum 2
Is opened to take out the coated powder particles P.

As shown in FIG. 2, a target plate driving unit 5 and a drum driving unit 6 are disposed on both sides of a vacuum chamber 4 so as to be retractable along guide rails 5a and 5b. Device was developed. The target plate drive unit 5 cantileverly supports a sputtering source 3 similar to that shown in FIG. The drum drive unit 6 includes a drive shaft that meshes with a drive shaft in the vacuum chamber 4 and rotates the rotary drum 2 inside the vacuum chamber 4.

The target plate drive unit 5 and the drum drive unit 6 are connected to the vacuum chamber 4 via hermetic joints 5b, 6b at their respective forward positions. Since the guide rail 6a is provided on the upper surface of the movable base 6c, the drum drive unit 6 moves in the X direction retreating from the vacuum chamber 4 and further in the Y direction perpendicular to the vacuum chamber 4. 2, a target 3c slightly shorter than the axial length of the rotary drum 2 is disposed obliquely downward.

At the initial position P ₀ shown in FIG.
Interior cleaned of, were charged raw material powder to be sputtered, to move the rotary drum 2 and the drum drive unit 6 by the traveling of the moving platform 6c to the standby position P ₁ that matches the axis of the vacuum chamber 4. Then, to advance the target plate driving unit 5 and the drum drive unit 6 in the operative position P _2, it is connected to the vacuum chamber through a gas-tight joint 5b, 6b.

After the inside of the vacuum chamber 4 is evacuated by the rotary pump 7a and the diffusion pump 7b of the vacuum system 7, a predetermined coating is applied to the raw material powder by sputtering while rotating the rotary drum 2 inside the vacuum chamber 4. . Then, the feed to the initial position P ₀ via the standby position P _1, rotating the coated powder drum 2
Remove from According to this method, a large-diameter rotary drum 2 can be used, and the production capacity can be improved.

[0012]

The inside of the rotating drum 2 where sputtering is performed is 1 × 10 ⁻³ Pa to 10 × 1.
The degree of vacuum is maintained at about 0 ^-2 Pa. On the other hand, the sputtering source 3 is designed mainly from the viewpoint of efficiently performing a sputtering reaction. Therefore, when the conventional sputtering source 3 is inserted inside the rotating drum 2,
A large space remains. Since a large amount of air and the like in the space is sucked and evacuated, it takes a long time to evacuate, and a large-capacity vacuum pump is required. This problem becomes a hindrance to productivity, particularly when the inner diameter of the rotary drum 2 is increased to increase production capacity.

As shown in FIGS. 1 and 2, the sputtering source 3 is required to be cantilevered from the viewpoint of apparatus design. The cantilever sputtering source 3 is apt to bend, and the target plate 3c and the rotating drum 2
The distance between the inner surface and the inner surface tends to fluctuate. When the distance fluctuates, the sputtering conditions change in the axial direction of the rotating drum 2, and it is difficult to perform uniform coating on the raw material powder loaded in the rotating drum 2. The bending deformation of the sputtering source 3 also increases with the size of the equipment.
Appears prominently when using.

The present invention has been devised to solve such a problem, and is suitable for powder coating using a rotating drum by modifying the cross-sectional shape of a sputtering source. It is an object of the present invention to provide a sputtering apparatus having a small space required to be pulled and having a strength enough to withstand cantilever support.

[0015]

SUMMARY OF THE INVENTION A sputtering apparatus according to the present invention is a sputtering apparatus for powder coating for coating raw material powder in a rotary drum housed in a vacuum chamber with sputter particles to achieve the object. A casing having a peripheral wall concentric with the inner peripheral surface of the rotating drum, a housing attached to the casing, forming a semi-cylindrical internal cavity between the casing and the casing, and attached to a lower side of the housing. And a backing plate having good thermal conductivity insulated from the housing, a water cooling mechanism disposed between the backing plate and the housing, and facing the raw material powder inserted into the rotating drum, A target plate attached to a backing plate, wherein one side opening of the rotating drum Is cantilevered arm inserted through the target drive unit in the projecting portion, and vacuum required internal space of the rotary drum is characterized in that it decreases by said casing.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS As shown in FIGS. 3 and 4, the sputtering apparatus of this embodiment includes a semi-cylindrical casing 10 formed concentrically with a rotary drum 2. As shown in FIG. Casing 1
In the inside of 0, cavities 12, 13 bisected by a reinforcing plate 11 are formed. The cavities 12 and 13 are airtightly shielded from the internal space of the rotating drum 2.

When the outer diameter of the casing 10 is determined in consideration of the inner diameter of the rotating drum 2, the internal space of the rotating drum 2 that requires evacuation can be greatly reduced. For example, assuming that the rotating drum 2 and the casing 10 have the same length L, and the inner diameter of the rotating drum 2 and the outer diameter of the casing 10 are T and t, respectively, the space in the rotating drum 2 that needs to be evacuated is the casing. Π (2R ² −
r ² ) · L / 2.

Further, since the outer surface of the casing 10 has a semi-cylindrical shape, the powder dropped from the inner peripheral surface of the rotary drum 2 does not adhere and accumulate. The cavities 12, 13
It becomes a heat insulation and insulation layer. The reinforcing plate 11 suppresses bending when the sputtering apparatus is cantilevered.

Mounting brackets 14 and 15 are fixed to both ends of the casing 10. This mounting bracket 14,
The housing 20 is fixed to the casing 10 via 15. The housing 20 has support plates 2 on both side edges.
1, 22 are projected vertically downward. Mounting bracket 1
Insulation material is incorporated in 4, 15 or support plate 2
By making the insulating members 1 and 22 electrically insulated from the backing plate 30.

The backing plate 30 is sandwiched between the support plates 21 and 22. A plurality of recesses for accommodating the magnets 31 to 33 are formed on the back surface of the backing plate 30. The magnetic shields 34 and 35 are doubly incorporated so that magnetic flux does not leak from the magnets 31 to 33 to the outside.

A target plate 40 is attached to the front side of the backing plate 30 by holding metal fittings 41 and 42. The backing plate 30 is made of a material having good thermal conductivity, such as copper or a copper alloy, for removing and cooling the target plate 40 that is heated during sputtering.

Backing plate 30 and housing 20
The water cooling mechanism 50 is disposed between the two. Water cooling mechanism 50
Forms a cooling water passage 53 between the plates 51 and 52. The plate 51 is fixed to the backing plate 30 via the insulator 54. During the sputtering, the casing 10 is set to the ground potential, and a high voltage is applied from the external power supply via the backing plate 30 to the target plate 40.
Is applied to

When this sputtering apparatus is incorporated in the powder coating apparatus described with reference to FIG. 2, it is cantilevered by the target drive unit 5 as shown in FIG. That is, the connection fitting 61 is fixed to one end of the sputtering apparatus A, and the arm 6 inserted through the target driving unit 5
2 is connected to the sputtering apparatus A via the connection fitting 61. Since the arm 62 is rotatably supported by the bearings 63 to 65, the target plate 40 of the sputtering apparatus A can be arranged in the rotary drum 2 at an appropriate inclination angle.

As described with reference to FIG. 2, the target drive unit 5 and the drum drive unit 6 move in the left-right direction in FIG. The target drive unit 5 shown in FIG. 5 is in the operating position advanced toward the vacuum chamber 4, and a flange plate 5 c provided on the front face of the target drive unit 5 is airtightly connected to a flange 4 a provided at an end of the vacuum chamber 4. Is done. The flange plate 6d of the drum drive unit 6 is also hermetically connected to the flange 4b at the opposite end of the vacuum chamber 4.

After the inside of the vacuum chamber 4 is evacuated to a vacuum atmosphere, the target plate 40 of the sputtering apparatus A is
Sputtered particles flying from the surface are attached to the surface of the raw material powder loaded in the rotating drum 2. At this time, since the proportion of the sputtering device A in the space in the rotary drum 2 is large, the time for evacuating the vacuum chamber 4 is reduced. The sputtering apparatus A can be made large as long as a space required for the sputtering reaction is secured between the target plate 40 and the raw material powder at the lower part of the rotary drum 2, whereby the inside of the rotary drum 2 required for evacuation is reduced. The space is reduced to less than 1/3.

This time reduction can be achieved by performing an operation of baking the rotary drum 2 and the vacuum chamber 4 to make the environment suitable for sputtering, or an operation of the vacuum chamber 4 after sputtering.
The same applies to the vacuum release operation when the interior is opened to the atmosphere. Therefore, powder sputtering can be performed quickly, and an increase in the capacity of a vacuum system required for evacuation is suppressed.

With the rotation of the rotating drum 2, the rotating drum 2
The raw material powder adhering to the inner surface rises with the rotation of the rotary drum 2 and drops from the inner peripheral surface when the adhering force becomes smaller than the gravity. The raw material powder is
Although it may fall upward, it slides down the semi-cylindrical slope of the casing 10 and does not adhere to or accumulate on the surface of the casing 10. Thus, the individual powder particles are equally exposed to sputtering, resulting in a uniform coating. In this regard, in a conventional sputtering apparatus having a flat upper surface, the raw material powder dropped from the rotating drum easily adheres and accumulates on the upper surface of the sputtering apparatus. The attached and deposited raw material powder remains uncoated, and when it is returned to the rotating drum by some impact, it causes a coating powder having a variation in the coating layer formation state.

Further, since the cylindrical casing 10 and the reinforcing plate 11 have a sufficient rigidity, bending of the cantilevered sputtering apparatus A is suppressed. for that reason,
The distance between the target plate 40 and the raw material powder on the lower part of the rotating drum 2 is kept constant. Therefore,
The entire amount of the raw material powder charged into the rotating drum 2 is efficiently exposed to sputtering, and a uniform coating is applied.

In the above embodiment, the powder coating of the type in which the rotary drum 2 is disposed in the vacuum chamber 4 has been described as an example. However, the invention is not restricted to this, but is equally applicable, for example, to a powder coating apparatus of the type shown in FIG. Further, instead of the cantilever support, the sputtering apparatus A can be supported on both the target drive unit 5 side and the drum drive unit 6 side. By supporting both ends, it is ensured that the sputtering apparatus A is held at a predetermined position, and the equipment can be enlarged.

[0030]

As described above, in the present invention, when the powdery raw material charged in the rotary drum is coated by sputtering, a sputtering apparatus having a cross section suitable for the internal space of the rotary drum is used. As a result, the space in the rotary drum that requires evacuation is reduced. Therefore, the time for adjusting the vacuum atmosphere suitable for sputtering is shortened, and a small vacuum pump can be used. Further, the bending in the longitudinal direction is suppressed by the strength improvement of the sputtering device due to the shape of the casing, and even in a cantilever-supported sputtering device, the distance from the target plate to the raw material powder does not change, and a constant powder coating is performed. be able to. Moreover, the raw material powder that has fallen from the inner surface of the rotary drum to the casing surface does not fall along the cylindrical slope of the casing and does not adhere to or accumulate on the casing surface. The individual powder particles are equally exposed to sputtering,
Emission of coating powder to which sputtered particles are insufficiently adhered is reduced. Further, since the space inside the casing functions as a heat insulating / insulating layer, protection of the device is also ensured.

[Brief description of the drawings]

FIG. 1 is a small powder coating apparatus proposed by the present inventors.

FIG. 2 is a large powder coating apparatus developed by the present inventors.

FIG. 3 shows a state in which a sputtering apparatus is mounted on a rotating drum of a large-sized powder coating apparatus in the embodiment of the present invention.

FIG. 4 is a sectional view of the sputtering apparatus.

FIG. 5 is a target drive unit on which the sputtering apparatus is set.

[Explanation of symbols]

A sputtering apparatus 2 rotating drum 10
Casing 12, 13 Cavity 20 Housing 30
Backing plate 40 target plate

──────────────────────────────────────────────────続 き Continuation of the front page (56) References Japanese Patent Publication No. 60-8303 (JP, B2) (58) Fields investigated (Int. Cl. ⁷ , DB name) C23C 14/00-14/58 B22F 1 / 02

Claims (1)

(57) [Claims] 1. A powder coating sputtering apparatus for coating a raw material powder in a rotary drum housed in a vacuum chamber with sputter particles, comprising: a casing having a peripheral wall concentric with an inner peripheral surface of the rotary drum ; The
Attached to the casing, and halfway between the casing and
A housing defining a cylindrical internal cavity, attached to the underside of the housing, and with good thermal conductivity backing plate is insulated and from said housing, said back
Water placed between the king plate and the housing
An arm having a cooling mechanism and a target plate opposed to the raw material powder inserted into the rotary drum and attached to the backing plate, and an arm inserted through the target drive unit at a portion protruding from one side opening of the rotary drum A sputtering apparatus for powder coating, wherein an inner space of the rotary drum required to be evacuated is reduced by the casing.