WO1995030780A1

WO1995030780A1 - Continuous magnetron sputtering machine

Info

Publication number: WO1995030780A1
Application number: PCT/FR1995/000579
Authority: WO
Inventors: Christian D. Lacroix; Yves Mate; Jean-Pierre L. Roiron
Original assignee: Societe Industrielle De Combustible Nucleaire
Priority date: 1994-05-04
Filing date: 1995-05-04
Publication date: 1995-11-16
Also published as: FR2719603B1; FR2719603A1

Abstract

A device for the continuous sputtering processing of the surfaces of moving rotary parts (R), consisting of at least one chamber defining a vacuum processing enclosure in which a plasma may be generated, and communicating with the outside via a feed or loading zone (10, 11) and a discharge or unloading assembly (20, 21). Said processing enclosure is provided with a set (16, 26) of two rotary screw conveyors for transferring the parts (R), which screw conveyors are parallel to the longitudinal axis of the chamber (1, 2), as well as two rails (17, 27) for guiding and supporting the parts (R), which rails are parallel to said screw conveyors and arranged therebetween, and capable of being given a predetermined electrical potential. At least the longitudinal ends of the rails are joined to a sloping ramp (18, 28) for joining them to the loading and unloading zones, and said screw conveyors are positioned and spaced apart according to the size of the part to be processed so that the ends of the part can engage the screw threads and contact the rail, whereby the part rotates as it is transferred between the loading and unloading zones.

Description

CONTINUOUS MAGNETRON CATHODE SPRAYING MACHINE.

The present invention relates to a device for the continuous surface treatment of revolution parts by magnetic sputtering under vacuum. It is already known to carry out a surface treatment (pickling or coating) by sputtering.

The parts to be treated are introduced into a device comprising in particular a chamber delimiting a vacuum treatment enclosure and in which a plasma, generally of argon, can be established. For coating operations, this chamber is equipped with at least one magnetron forming the source of the metallic material intended to be deposited by atomic migration on the part to be treated.

The room communicates with the outside by at least one entry airlock and at least one exit airlock.

However, these traditional devices do not allow processing of a continuous series of pieces without interruption of treatment. In addition, in the case of parts having a complex geometry, it is necessary to make the parts mobile inside the chamber so as to produce a complete and uniform pickling or coating.

Finally, they do not allow for quick and easy maintenance.

The present invention aims to solve these technical problems satisfactorily.

This object is achieved by means of a device for the continuous surface treatment of parts of revolution by sputtering consisting of at least one chamber delimiting a vacuum treatment enclosure in which a plasma can be established and communicating with the exterior by an entry or loading airlock and an exit or unloading airlock, characterized in that said treatment enclosure is provided on the one hand with a set of two rotary helical screws for transferring the pieces extending parallel to the longitudinal axis of the chamber and on the other hand of two guide rails and for supporting the parts extending between and parallel to said screws, being capable of being brought to a determined electrical potential and being extending at least at their longitudinal ends by an inclined ramp connecting with the airlocks; said screws being positioned and separated by a distance determined according to the dimensions of the part to be treated so as to allow both the engagement of its ends in the thread of the screws and the contact with the rail and thus effect between the loading and unloading locks the transfer of the part by rotation.

According to an advantageous characteristic, said loading or unloading ramp comprises a first fixed section electrically connected to ground, a second section capable of being brought to a floating electrical potential and a third section brought to an electrical working potential. In some cases, it is advantageous to use a second tilting section to avoid any marking of the parts by the production of electric arcs during sudden variations in the potential of the parts.

Preferably, the entry and exit airlocks consist of a casing containing a rotary cylindrical barrel provided with at least one longitudinal cell intended to receive a part to be treated; the clearance between the internal face of the casing and the casing of the barrel being determined to allow its rotation without breaking the vacuum prevailing inside the chamber.

In particular, the device comprises a pickling chamber mounted in series with a coating chamber, said chambers being able to be isolated from one another by an intermediate airlock. In addition, the entry or exit airlocks may consist of several modules, depending on the level of leakage tolerable for the surface treatment carried out.

Advantageously, said coating chamber is provided with at least one magnetron disposed opposite the transfer path of the parts and whose characteristics are determined according to the type of deposit to be made.

According to another characteristic, said chamber consists of a box arranged horizontally, the upper face of which forms an articulated cover allowing the access to the treatment enclosure by pivoting and the lower face of which forms a separable plate on which the games are mounted. transfer screws and guide rails. It is also expected that the pivoting cover of the box forming the coating chamber carries said magnetron.

Another object of the invention is a use of the above device for the surface treatment of pieces of revolution by continuous parade by magnetic cathode sputtering under vacuum.

The invention applies in particular and, for example, to the surface treatment of shock absorber rods and distributor cylinder axes.

The device of the invention makes it possible to carry out all types of continuous deposits with high rates. This device can be easily integrated into a production line and its implementation for carrying out surface treatments does not produce any effluent.

In addition, the device of the invention allows complete and rapid accessibility of the functional organs, which facilitates maintenance operations.

The invention will be better understood on reading the description which follows, accompanied by the drawings in which:

- Figure 1 shows a schematic overview of the device of the invention; - Figures 2a and 2b show respectively front elevation and top views of the device of the invention;

- Figure 3 is a side elevational view of the device of Figures 2a and 2b;

- Figure 4 is a detail view of the device of the invention; and,

- Figures 5a and 5b are other detailed views of the device of the invention in partial side section respectively for the second fixed section and second tilting section versions.

The device shown diagrammatically in FIG. 1 is intended for the continuous surface treatment of parts of revolution R by sputtering under vacuum.

This device comprises one or more chambers 1,2 in series each delimiting a treatment enclosure in which a plasma is formed and communicating with the outside by an entry airlock 10,11 or loading and an exit airlock 20,21 or unloading. In the embodiment shown, the airlocks consist of two modules in series.

The two chambers 1,2 are isolated from each other by an intermediate airlock 12. The parts R are stored in a loading station C before being successively introduced into the entry airlock 10,11, in the pickling chamber 1 then in the coating chamber 2 by the intermediate airlock 12 before being extracted from the device at the unloading station D. The inlet airlock 10,11, intermediate 12 and outlet 20,21 are associated with pumping means P. Likewise, the chambers 1,2 are equipped with pumping means P '. A working gas is introduced into the pickling enclosure 1 through the pipe 13. The enclosure 1 is moreover provided with a closable pipe 14 for venting to the open air and pressure sensors 15.

In addition to the above means, the coating chamber 2 is also provided with at least one magnetron 22 disposed opposite the transfer path of the parts R and whose characteristics are determined according to the type of deposit to be made. As shown in FIG. 4, each treatment enclosure is provided with a set 16,26 of two rotary helical transfer screws extending parallel to the longitudinal axis of the chambers 1,2 and of two guide and support rails 17.27 extending parallel to said screws. The rails 17, 27 and the sets of screws 16, 26 are positioned as a function of the dimensions and in particular of the greatest length of the part R so as to allow the transverse support of the part between the screws.

The cooperation between the threads of the screws 16, 26 and the ends of the part as well as the adjustment of the rotational speeds of said screws allow the transfer at constant speed of the part without accidental modification of the trajectory. The screws of the pickling and depositing chambers respectively may have different pitches, which makes it possible to obtain optimized spacings between the parts according to the treatment carried out. The guide and support rails 17, 27 and therefore the part R are optionally brought to a determined electrical potential either to allow the formation of the pickling plasma, or to electrically polarize the parts during the deposition phase. The rails 17, 27 are extended at their longitudinal ends by inclined ramps 18, 28 junction with the airlocks.

Each of the ramps comprises, as shown in FIG. 5a from the airlock, a first section 181 grounded, a second section 182 left at a floating electrical potential and a third section 183 brought to a determined potential.

The entire ramp is supported by a base 180. The three sections 181, 182, 183 are separated by a slight clearance allowing them to be electrically isolated from each other. In addition, an electrical insulator 19 is placed between the respective lower faces of the second and third sections 182, 183 and the upper face of the base 180.

As shown in FIG. 5b, to eliminate the electric arcs on the parts R, the second section 182 can be tilted around an axis 184. The tilting is caused by the weight of the part R when it rolls on the second section , which allows the passage of this section alternately in contact with a zone 190 of the base 180, at the electrical potential of the ground to a zone 191 at the potential necessary for the treatment (ion pickling or polarization). Zone 190 is electrically connected to the first section 181 while zone 191 is connected to the third section 183. The two zones 190, 191 are separated by an insulating element

192.

The part coming from the entry airlock 10,11 or from the intermediate airlock 12 rolls in transverse position successively on the first section 181 and the second section 182 of the inclined ramp 18,28 before passing on the third section 183 to arrive until to the rail 17,27 where its lateral ends will engage in the thread of the screws 16,26. Then, during its rolling, the part remains constantly in contact with the rail 17, 27 in order to be maintained at the electrical potential.

Symmetrically, the part R, at the end of the treatment operation, passes from the running rails 17.27 and the screws 16.26 to the exit airlock 20.21 or to the intermediate airlock 12 by a set of three sections of the same type allowing to pass from the electric potential of work to the mass.

The entry airlock 10,11, the intermediate airlock 12 and the exit airlock 20,21 are made up of identical modules. Each module consists of a casing 101 containing a cylindrical barrel 102, rotary and provided with one or more cells 103. The cell 103 is produced longitudinally on the barrel 102 and is intended to receive a part R to be treated. The clearance between the inner face of the casing 101 and ^• the envelope of the cylinder 102 is determined depending upon the permissible leakage level for the treatment considered.

The rotation of the barrel 102 inside the casing allows the part R to pass from the loading station C or from a first chamber 1 to the entrance to the immediately adjacent chamber or else to the unloading station D without breaking the vacuum inside the rooms.

To strengthen the tightness of the chambers, in particular at the level of the loading stations C or unloading stations D, it is possible to have several airlock modules in series.

In this case, a short junction section 111 is provided between the modules. Each of the chambers 1,2 consists of a parallelepipedic box 100,200 arranged horizontally and the upper face of which forms an articulated cover 100a, 200a allowing, by pivoting and lifting, accessibility to the treatment enclosure.

The cover 200a of the box 200 of the coating chamber 2 carries the magnetron (s) 22, which facilitates their maintenance.

The underside of the box 100,200 forms a separable plate 100b, 200b on which are mounted the sets of transfer screws 16,26 and the guide rails 17,27. A system for gripping and guiding the plate 100b, 200b is arranged under the box 100,200. This system includes a vertical lifting table 4 coupled to a horizontal bracket 3. The lifting table 4 is mounted under the base of the box and makes it possible to lower the plate 100b, 200b to the level of the bracket 3. The bracket 3 is arranged laterally under the level of the base of the box and allows to translate the tray 100b to release it.

Claims

CLAIMS 1. Device for surface treatment of continuous pieces of revolution (R) by cathode sputtering consisting of at least one chamber delimiting a vacuum treatment chamber in which a plasma can be established and communicating with the outside by an entry or loading airlock (10,11) and an exit or unloading airlock (20,21), characterized in that said treatment enclosure is provided on the one hand with a clearance (16,26) two rotary helical screws for transferring the parts (R) extending parallel to the longitudinal axis of the chamber (1,2) and on the other hand two rails (17,27) for guiding and supporting the parts ( R) extending between said screws and parallel to the latter, being capable of being brought to a determined electrical potential and extending at at least their longitudinal ends by an inclined ramp (18, 28) connecting with the airlocks; said screws being positioned and separated by a distance determined according to the dimensions of the part to be treated so as to allow both the engagement of its ends in the thread of the screws and contact with the rail and thus effect between the loading and unloading locks the transfer of the part by rotation.

2. Device according to claim 1, characterized in that said ramp (18,28) comprises a first fixed section (181) electrically connected to ground, a second section (182) left at a floating electrical potential and a third section ( 183) brought to work potential.

3. Device according to claim 2, characterized in that said second section (182) can tilt under the weight of the part R around an axis (184) to come alternately into contact on the one hand with an area at the mass and on the other hand an area with treatment potential.

4. Device according to one of the preceding claims, characterized in that the entry and exit airlocks (10,11,12,20,21) consist of a casing (101) containing a cylindrical barrel (102) rotary provided with at least one longitudinal cell (103) intended to receive a part (R) to be treated; the clearance between the internal face of the casing (101) and the casing of the barrel (102) being determined to allow its rotation without breaking the vacuum prevailing inside the chamber (1,2).

5. Device according to one of the preceding claims, characterized in that it comprises a pickling chamber (1) mounted in series with a coating chamber (2), said chambers being isolated from one another by a intermediate airlock (12).

6. Device according to one of the preceding claims, characterized in that it comprises one or more entry airlock modules (10,11) in series for loading said chamber (1) and one or more airlock modules outlet (20,21) in series for unloading.

7. Device according to claim 5, characterized in that said coating chamber (2) is provided with at least one magnetron (22) disposed opposite the transfer path of the parts (R) and whose characteristics are determined according to the type of deposit to be made.

8. Device according to one of the preceding claims, characterized in that said chamber (1,2) consists of a box (100,200) arranged horizontally, the upper face of which forms a hinged cover (100a, 200a) allowing the l accessibility to the treatment enclosure and the underside of which forms a separable plate (100b, 200b) on which the sets of transfer screws (16, 26) and the guide rails (17, 27) are mounted.

9. Device according to claims 6 and 8, characterized in that the pivoting cover (100a, 200a) of the box (100,200) forming the coating chamber (2) carries said magnetron (22).

10. Use of a device according to one of claims 1 to

9 for the continuous surface treatment of revolutionary parts by magnetic sputtering under vacuum.