Baffled liner cover
View Patent ↗A baffled liner cover supported at the top of a liner surrounding a wafer support tower for semiconductor thermal processing. The cover may present a continuous horizontal surface for preventing particles from falling within the liner but present horizontal extending gas passageways in a baffle assembly to allow the flow of processing gas through the cover. In one embodiment, the baffle assembly includes a cup-shaped member disposed in a central aperture of a top plate having an open top, a continuous bottom, horizontal holes through the sides, and a flange around sides defining a convolute annular passage. Alternatively, the planar top plate may included slanted holes therethrough or vertical holes occupying a small fraction of the surface area. The liner and cover may be composed of quartz, silicon carbide, or preferably silicon.
1. A liner assembly for use in a thermal processing furnace, comprising:
a generally tubular liner having sides extending along a central axis for accommodating a tower supporting a plurality of wafers in a horizontal orientation; and
a cover disposed at least partially over a top of the liner having convolute passageways passing therethrough, part of the passageways extending perpendicular to the central axis and another part of the passageways extending parallel to the central axis, wherein the cover includes an outer annular portion supported on the liner and a central part having an inner annular portion fit into a central aperture of the outer annular portion, and a floor member having an upwardly extending rim forming an inverted cup shape, and the passageways penetrating sidewalls of the central part and passing in between the central part and the upwardly extending rim.
2. The assembly of claim 1 , wherein the cover is not fixed to the liner.
3. The assembly of claim 1 , wherein the cover is fixed to the liner.
4. The assembly of claim 1 , wherein the liner and cover consist of at least 99 at % silicon.
5. The assembly of claim 1 , wherein the liner and cover comprise at least one multi-component silicon-containing material selected from the group consisting of quartz and silicon carbide.
6. The assembly of claim 1 , wherein the cover fits partially within a central aperture of a top plate of the tower fixed to legs of the tower on which the wafers are supported.
7. The assembly of claim 1 , wherein the outer annular portion includes a planar portion and a rim descending therefrom.
8. The liner assembly of claim 1 , wherein the cover includes a continuous floor extending through and perpendicularly outwardly from the central axis at an axial position below the passageway axes and being exposed to a top of the thermal processing furnace.
9. A baffled liner cover to be fit over the top of a tubular liner configured to accommodate within the liner a substrate support tower, comprising:
a cover plate extending in a plane about an axis and having peripheral edges to be supported on the liner and having a central aperture;
a baffle assembly having an annular portion at its top fit to the aperture, a generally tubular wall open at its top in a plane of the cover plate, extending parallel to the axis, and having horizontal passageways therethrough, and supporting at its bottom a continuous floor extending perpendicularly to and radially outwardly from the axis, the floor having an upwardly extending rim, and a convolute gas passageway joined to the horizontal passageways formed in between the tubular wall and the cover plate.
10. The cover of claim 9 , wherein the baffle assembly further comprises an annular flange connected to an outer portion of the floor and extending upwardly toward the cover plate and creating an annular vertical passageway between it and the tubular wall adjacent the horizontal holes and a connected annular horizontal passageway between it and a bottom of the cover plate.
11. The cover of claim 10 , wherein the cover plate and the baffle assembly both comprise a multi-component silicon-containing material selected from the group consisting of quartz and silicon carbide.
12. The cover of claim 10 , wherein the cover plate and the baffle assembly both comprise a material which is silicon.
13. The cover of claim 9 , wherein the cover plate and the baffle assembly comprises a multi-component silicon-containing material selected from the group consisting of quartz and silicon carbide.
14. The cover of claim 9 , wherein the cover plate and the baffle assembly both comprise a material which is silicon.
15. The liner assembly of claim 9 , further comprising the tower which includes legs supporting the wafers and fixed to a top plate having a central aperture accommodating therein lower portions of the baffle assembly.
16. The liner assembly of claim 9 , wherein the floor extends through the axis and is exposed to a space over the tubular liner.