Baffled liner cover

Abstract

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.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a side cross-sectional view of an thermal processing furnace and various parts contained therein and including one embodiment of the invention

FIG. 2 is a sectioned side view of a liner cover according to a second embodiment of a liner cover of the invention.

FIGS. 3 and 4 are sectioned orthographic views of a liner cover according to a third embodiment of the invention.

FIGS. 5, 6, and 7 are cross-sectional views of liner covers according to fourth, fifth, and sixth embodiments of the invention.

Claims

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; anda cover over a top of the liner having passageways passing therethrough and extending along passageway axes at least partially inclined to the central axis.

2. The assembly of claim 1, wherein the tubular liner comprises a plurality of staves bonded together.

3. The assembly of claim 1, wherein the cover is not fixed to the liner.

4. The assembly of claim 1, wherein the cover is fixed to the liner.

5. The assembly of claim 1, wherein the liner and cover consist of at least 99 at % silicon.

6. The assembly of claim 1, wherein the liner and cover comprise at least one material selected from the group consisting of quartz, and silicon carbide.

7. The assembly of claim 1, wherein portions of the passageway extend perpendicularly to the central axis.

8. 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.

9. The assembly of claim 1, wherein the cover includes an outer annular and planar portion and a central part fit into a central aperture of the annular portion and including the passageways.

10. The assembly of claim 1, wherein the cover includes a disk shaped flat plate and wherein the passageways are bored at one or more inclined angles in the plate.

11. 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; anda cover over a top of the liner having passageways passing therethrough which occupy no more than 10% and at least 0.5% of an area of a top of the liner.

12. The assembly of claim 11, wherein the holes extend at least partially along a direction inclined to the central axis.

13. The assembly of claim 11, wherein the liner and cover both comprise a common material selected from the group consisting of silicon, quartz, silicon carbide.

14. The assembly of claim 13, wherein the material is silicon.

15. 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 top 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 a rim at its top fit to the aperture, a generally tubular wall open at its top in a plane of the top plate, extending parallel to the axis, and having horizontal holes therethrough, and supporting at its bottom a continuous floor extending perpendicularly to the axis.

16. The cover of claim 15, wherein the baffle assembly further comprises an annular flange connected to an outer portion of the floor and extending upwardly toward the top 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 top plate.

17. The cover of claim 16, wherein the top plate and the baffle assembly comprises a material selected from the group consisting of silicon, quartz, and silicon carbide.

18. The cover of claim 17, wherein the material is silicon.

19. The cover of claim 15, wherein the top plate and the baffle assembly comprises a material selected from the group consisting of silicon, quartz, and silicon carbide.

20. The cover of claim 19, wherein the material is silicon.