Magnetic latch for a vapour deposition system
View Patent ↗The invention relates to a magnetic latch for securing substrates on a planetary rotating platform suspended above a coating source in a vacuum chamber of a vapor deposition system, e.g. a chemical vapor deposition (CVD) system or a physical vapor deposition (PVD) system. The magnetic latch includes a permanent magnetic, which is moveable between a latching position, in which the permanent magnet magnetizes the latch for attracting a substrate holder, and an unlatching position, in which the permanent magnet is connected in a bypass circuit, thereby demagnetizing the latch for releasing the substrate holder.
1. A planetary substrate support for mounting in a process chamber of a coating system, which is for coating substrates mounted on substrate holders, comprising:
a process chamber;
a main support, located within the process chamber, rotatable about a first axis;
a plurality of spindles extending from the main support, located within the process chamber, rotatable about respective spindle axes which are different axes than the first axis;
a magnetic latch on an end of each spindle, each magnetic latch located within the process chamber and including a permanent magnet and a mounting surface;
a plurality of substrate holders selectively connectable and disconnectable to the mounting surfaces of the magnetic latches;
wherein each magnetic latch is configured to selectively magnetically connect and disconnect one of the substrate holders to its mounting surface, and wherein each magnetic latch is configured to be operable such that each magnetic latch magnetizes and demagnetizes its respective mounting surface; and
wherein each magnetic latch includes a first section, and a second section movable relative to the first section between a first position in which the permanent magnet forms a magnetic circuit with poles on the first and second sections, which magnetizes the mounting surface for attracting one of the substrate holders, and a second position in which the magnet circuit is short circuited and the mounting surface is demagnetized, thereby to release one of the substrate holders from the magnetic latch and enabling the substrate and substrate holder to be removed from the magnetic latch and the process chamber.
2. The planetary substrate support according to claim 1 , wherein each of the first sections comprises a stator including the mounting surface, and poles for aligning with the permanent magnet; and
wherein each of the second sections comprises a rotor, including the permanent magnet for rotation between the first position in which the permanent magnet is aligned with the poles of the stator, and the second position in which the permanent magnet is not aligned with the poles of the stator, thereby making the stator non-magnetic.
3. The planetary substrate support according to claim 1 , wherein each magnetic latch further comprises an actuator extending through the main support and the spindle for moving the second section relative to the first section from outside the process chamber.
4. The planetary substrate support according to claim 2 , wherein each rotor includes a plurality of permanent magnets; and each stator includes a plurality of poles for aligning with the plurality of permanent magnets.
5. The planetary substrate support according to claim 4 , wherein each rotor includes a rotor pole on each side of each permanent magnet for aligning with respective stator poles, which forms a magnetic circuit through the mounting surface when in the first position, and for engaging a single stator pole, which shorts the permanent magnet when in the second position.
6. The planetary substrate support according to claim 1 , further comprising a substrate holder for supporting the substrate including a ferromagnetic portion for attraction by the magnetic latch.
7. The planetary substrate support according to claim 6 , wherein the substrate holder includes a first aligning feature; and wherein each magnetic latch includes a second aligning feature for engaging the first aligning feature.
8. The planetary substrate support according to claim 7 , wherein the first and second aligning features are in the center of the substrate holder and each magnetic latch, respectively.
9. The planetary substrate support according to claim 6 , wherein the substrate holder comprises an annular ring surrounding the substrate.
10. The planetary substrate support according to claim 1 , wherein each magnetic latch is for suspending a substrate holder above a coating source.