Quick-change precursor manifold for large-area CVD and PECVD
View Patent ↗A tube-array showerhead for CVD or PECVD on large substrates delivers precursors to a process chamber via an array of tubes drilled with precision holes. The tubes rapidly become contaminated with use and must be changed frequently to maintain process quality. An improved manifold for a tube-array showerhead, intended for processes with a low pressure differential between the tubes and process chamber, includes holding-stubs to hold each tube by its ends outside the manifold block. At least one holding-stub for each tube is spring-loaded along the direction of the tube's operating axis. Contaminated tubes can be removed, and clean tubes installed, without disassembling the manifolds or disturbing any high-pressure-differential seals to the ambient atmosphere or precursor supplies. This invention reduces production costs by decreasing chamber down-time and reducing the risk of creating leaks when tubes are changed.
1. A tube-array showerhead, comprising:
two precursor plena, each having at least one plenum inlet for receiving precursors to be distributed,
two manifold blocks, attached to the precursor plena and each having at least one precursor inlet for receiving precursors from the attached plenum,
at least one pair of tube seals, where one of the seals in each pair is inserted in each manifold block to seal the precursor inlet,
at least one compressible spring attached to at least one of the manifold blocks opposite the tube seal,
at least one pair of holding-stubs, where
one of the holding-stubs in each pair is sealed into each of the manifold blocks by the tube seal inserted in the manifold block, and
at least one of the holding-stubs is spring-loaded by the compressible spring;
at least one hollow tube,
held at each end by one of the holding-stubs,
compressed along its longitudinal axis by the compression spring, and
having at least one lateral hole to distribute the received precursors,
at least one electrical source capable of generating an electric field to excite precursors into a plasma,
at least one electrical connection to the electrical source through at least one of the manifold blocks, and
at least one electrical insulator configured and positioned to insulate the electrical connection from the manifold block and from any other nearby electrical connections,
where at least one of the electrical connections connects the electrical source to at least one of the holding-stubs, and
each of the connected holding-stubs has a conductive portion that conducts electricity from the holding-stub to the hollow tube held by the holding-stub.
2. The showerhead of claim 1 , where at least one of the holding-stubs for each of the hollow tubes further comprises:
a narrow snout that compresses the compression spring when a tube is installed, and
a shoulder that mates with a mating surface sealed to the manifold block when the compression spring is compressed.
3. The showerhead of claim 2 , where at least one of the holding-stubs and at least one end of at least one of the tubes are capable of mating by contact between a concave conical surface and a convex spherical surface.
4. The showerhead of claim 1 , where at least one of the electrical connections connects the electrical source to at least one of the hollow tubes.
5. The showerhead of claim 1 , where at least one of the holding-stubs for each of the hollow tubes further comprises:
a narrow snout that compresses the compression spring when a tube is installed, and
a shoulder that mates with a mating surface sealed to the manifold block when the compression spring is compressed.
6. The showerhead of claim 5 , where at least one of the holding-stubs and at least one end of at least one of the tubes are capable of mating by contact between a concave conical surface and a convex spherical surface.
7. The showerhead of claim 1 , where the electrical insulator is also configured to mechanically and thermally insulate the holding-stub, and prevent unwanted buildup of deposits on the holding-stub.
8. The showerhead of claim 7 , where the electrical insulator further comprises at least part of the seal.
9. The showerhead of claim 8 , where at least one of the holding-stubs and at least one end of at least one of the tubes are capable of mating by contact between a concave conical surface and a convex spherical surface.
10. The showerhead of claim 9 , where at least one of the holding-stubs for each of the hollow tubes further comprises:
a narrow snout that compresses the compression spring when a tube is installed, and
a shoulder that mates with a mating surface sealed to the manifold block when the compression spring is compressed.
11. The showerhead of claim 10 , where the shoulder and its mating surface are capable of mating by contact between a concave conical surface and a convex spherical surface when the compression spring is compressed.