End-block for a rotatable target sputtering apparatus
An end-block for electrically energising a rotatable tubular target in a vacuum coating installation is disclosed. The end-block has a rotary electrical contact that reduces the joule heating effects when operating in alternating current mode. When compared to known end-blocks, this is achieved by increasing the number of contact areas between a contacting ring and a series of circumferentially mounted contacting shoes. Also the contact shoes are being pressed radially outwardly by means of resilient elements against the contacting ring.
1. An end-block for energising a rotatable sputtering target, comprising a cylindrical socket and a spindle coaxially mounted inside said socket, said socket and spindle being relatively rotatable to one another, said socket comprising at least one electrical contact ring for forming an electrical end, wherein said spindle comprises at least two electrically conducting shoes, said shoes for providing an electrically sliding contact with the inner surface of said ring, each of said shoes being pressed radially and outwardly against said inner surface by means of at least one resilient element, said shoes being electrically connected in parallel to said spindle.
2. The end-block according to claim 1 , wherein the number of electrically conducting shoes is any one number from four to sixteen.
3. The end-block according to claim 1 ,
wherein said socket comprises at least two of said electrical contact rings, said rings being mounted coaxially to one another and electrically insulated from one another, each one of said shoes making electrical contact with the inner surface of at least one of said rings, all of said electrical contact rings being connected in parallel to said electrical end.
4. The end-block according to claim 1 ,
wherein each of said shoes is pressed against each of said rings by a number of resilient elements, said number being one of one or two or three or four.
5. The end-block according to claim 4 , wherein said resilient elements are metallic springs.
6. The end-block according to claim 4 , wherein said resilient elements are elastomer springs.
7. The end-block according to claim 1 , wherein at least one of said electrically conducting shoes has a trapezoidal footprint contacting the inner surface of said at least one ring.
8. The end-block according to claim 1 ,
wherein said socket has a hollow in said at least one ring for collecting wear particles from said shoes.
9. The end-block according to claim 1 ,
wherein said shoes are made from material comprising silver or copper or graphite or molybdenum disulfide.
10. The end-block according to claim 1 , wherein said socket is mounted immovable to said end-block.
11. The end-block according to claim 1 ,
wherein said spindle is mounted immovable to said end-block.
12. A sputtering apparatus comprising an end-block according to claim 1 .