Fastener system for supporting a liner plate in a gas showerhead reactor
View Patent ↗A fastener system and method for supporting and retaining modular insulating quartz liners with gas apertures in close proximity to corresponding apertures in diffusers of gas showerheads. Tubular fasteners have a head, a tubular shank and a foot that extend through a liner plate nozzle into a diffuser plate. A keyway in the gas diffuser, aligned and coaxial with a diffuser nozzle, allows the foot to reach an arcuate concourse through a keyway where it can be locked by bayonet turning. The keyway is machined into the diffuser by EDM and is an inversion of the fastener tip geometry rotated about the axis of the tubular shank. Each fastener and nozzle set form a coaxial path for distributing processing gas to substrates through liner and diffuser plates from a plenum in showerheads of a MOCVD reactor.
1. A fastener for joining two members of a gas showerhead reactor comprising:
first and second planar members of a gas nozzle array associated with a showerhead of a gas reactor, wherein nozzles in each planar member are aligned for gas passage from one side of the joined members to the opposite side; and
a hollow fastener fitting into the first and second members, each fastener having a tubular shank extending completely through said one of the first and second members and having a head for stopping passage of the shank beyond a distance in said one of the first and second members with a foot extending from the shank opposite the head at a distance extending partially into the other of the first and second members through a keyway, the tubular shank and foot surrounding a hollow central region forming a nozzle extending completely through said one of the first and second members and partially through the other of the first and second member to a nozzle of the other of the first and second members, the other member having an arcuate concourse communicating with the keyway, whereby the foot may be turned in the concourse, locking the second member to the first member in a bayonet tip manner.
2. The fastener of claim 1 wherein said first and second planar members are spaced apart by a gap.
3. The fastener of claim 2 wherein a washer resides on the tubular shank in said gap.
4. The fastener of claim 1 wherein the foot is an oblong tab having oppositely extending portions extending symmetrically from the tubular shank.
5. The fastener of claim 1 wherein the head fits into a countersunk region of said one of the first and second members.
6. The fastener of claim 1 wherein the diameter of the tubular shank fits closely within the nozzle of said one of the first and second members.
7. The fastener of claim 1 wherein the keyway is a portion of a machined slot in said other member.
8. The fastener of claim 1 wherein the nozzle of the other member is coaxial with the portion of the tubular shank extending into the second member and having a different diameter than the nozzle in said one member.
9. The fastener of claim 1 wherein said one member is a gas showerhead liner.
10. The fastener of claim 1 wherein the other member is a gas showerhead diffuser.
11. A fastener system for joining gas nozzle arrays of a gas diffuser plate and a liner plate in a MOCVD showerhead comprising:
a liner plate having opposed major surfaces with liner nozzles extending from a first major surface to a second major surface;
a diffuser plate for dispensing gas from a showerhead having a region parallel to a region of the liner plate where the liner plate and diffuser plates are to be joined together, the diffuser plate having diffuser nozzles corresponding in location to liner nozzles, the diffuser plate having axial keyways in the parallel region aligned with diffuser nozzles, each keyway terminating in an arcuate concourse; and
fasteners forming at least some of the liner nozzles and forming diffuser nozzles extending partially into the diffuser plate from the liner nozzles of the fasteners to diffuser nozzles outside of the fasteners, each fastener having a tubular shank with opposed first and second ends fitting through the liner plate and allowing gas passage therethrough, with the shank having a head at one end and a foot extending radially outwardly near the opposite end, the shank having sufficient length to pass through the liner plate with the radially extending foot passing along the keyway to the arcuate concourse of the diffuser plate, whereupon turning of the head turns the foot in the concourse in a bayonet tip manner joining the liner plate and the diffuser plate.
12. The system of claim 11 wherein the head is countersunk into a major surface of the liner plate.
13. The system of claim 11 wherein the foot is an oblong tab having oppositely extending portions extending symmetrically from the tubular shank.
14. The system of claim 11 wherein the keyway is coaxial with a nozzle in the diffuser plate.
15. The system of claim 11 wherein the diffuser is cooled by a flowing fluid.