Tube formed of bonded silicon staves
View Patent ↗Tubular silicon members advantageously formed by extrusion from a silicon melt or by fixing together silicon staves in a barrel shape. A silicon-based wafer support tower is particularly useful for batch-mode thermal chemical vapor deposition and other high-temperature processes, especially reflow of silicate glass at above 1200° C. The surfaces of the silicon tower are bead blasted to introduce sub-surface damage, which produces pits and cracks in the surface, which anchor subsequently deposited layer of, for example, silicon nitride, thereby inhibiting peeling of the nitride film. Wafer support portions of the tower are preferably composed of virgin polysilicon. The invention can be applied to other silicon parts in a deposition or other substrate processing reactor, such as tubular sleeves and reactor walls. The tower parts are preferably pre-coated with silicon nitride or polysilicon prior to chemical vapor deposition of these materials, or with silicon nitride prior to reflow of silica.
1. A silicon tube having a longitudinal axis, comprising: a plurality of at least twelve silicon staves consisting of silicon and less than 1% atomic fraction of elements other than silicon, arranged in a circular pattern about the longitudinal axis and enclosing a bore in which an object can be accommodated, wherein all the silicon staves extend in a direction parallel to the longitudinal axis and wherein neighboring ones of the silicon staves abut one another and are bonded together.
2. The tube of claim 1 , wherein the staves are welded together across respective interfaces between the neighboring ones of the silicon staves.
3. The tube of claim 1 , further comprising a cured bonding agent disposed and cured within interfaces between faces of neighboring ones of said staves and bonding the neighboring staves together.
4. The tube of claim 3 , wherein the bonding agent comprises a silica-based spin-on glass.
5. The tube of claim 1 , wherein the staves have grooves and tongues fittable in said grooves and extending parallel to the longitudinal axis.
6. The tube of claim 1 , wherein the staves comprise virgin polysilicon.
7. The tube of claim 1 , wherein each of said staves comprises two parallel faces, one of which faces the bore.
8. The tube of claim 1 , wherein, when the staves are fixed together, their interior surfaces adjacent the bore are circularly shaped.
9. A closed tubular wall having a longitudinal axis, comprising a plurality of silicon plates consisting of silicon and less than 1% atomic fraction of components other than silicon, wherein neighboring ones of the silicon plates abut one another and are pairwise bonded together to form a closed structure about the longitudinal axis and enclosing a bore extending along the longitudinal axis, and wherein outer surfaces of the plates on sides opposite the bore are arranged in a polygonal shape.
10. The tube of claim 9 , further comprising a spin-on silica glass disposed within interfaces between the plates.
11. The tube of claim 10 , wherein the plates are welded together across respective interfaces between the neighboring ones of the silicon plates.
12. The tube of claim 9 , wherein the plates comprise virgin polysilicon.
13. A silicon tube, comprising a plurality of silicon staves extending parallel to a central axis, wherein neighboring ones of the silicon staves abut one another and are fixed together to form a closed structure enclosing an interior bore capable of accommodating an object.
14. The tube of claim 13 , wherein the plurality of silicon staves comprises twenty of the silicon staves.
15. The silicon tube of claim 13 , wherein said staves are composed of virgin polysilicon.
16. The silicon tube of claim 13 , wherein the staves are welded together across respective interfaces between the neighboring ones of the silicon staves.
17. The silicon tube of claim 13 , wherein said staves are bonded together.
18. The silicon tube of claim 13 , further comprising a silica glass formed within interfaces between the silicon staves and joining the silicon staves into the tube.
19. The silicon tube of claim 13 , wherein each of the silicon staves comprises two parallel faces, one of which faces the interior bore.