Browse Prior Art Database

Labyrinth Mist Trap

IP.com Disclosure Number: IPCOM000060676D
Original Publication Date: 1986-Apr-01
Included in the Prior Art Database: 2005-Mar-09
Document File: 1 page(s) / 11K

Publishing Venue

IBM

Related People

Whitaker, CR: AUTHOR

Abstract

To prevent low viscosity liquids from collecting on the back side of silicon wafers and eventually getting into the vacuum chuck or spindle bearing of a spinning tool, a multi-channel collector is mounted in close proximity to the underside of the wafer. Back-splashed droplets or mist is prevented from accumulating on the back side of wafers and getting to the vacuum chuck or the spindle bearing by this labyrinth mist trap (LMT).

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Labyrinth Mist Trap

To prevent low viscosity liquids from collecting on the back side of silicon wafers and eventually getting into the vacuum chuck or spindle bearing of a spinning tool, a multi-channel collector is mounted in close proximity to the underside of the wafer. Back-splashed droplets or mist is prevented from accumulating on the back side of wafers and getting to the vacuum chuck or the spindle bearing by this labyrinth mist trap (LMT).

The figure is a cross-section showing a conventional spin tool, with its liquid catcher bowl 2 modified by mounting the LMT 4 to an existing inner ring 6 of the bowl 2 structure. A wafer 8 is mounted on the vacuum chuck 10. When a liquid 12 is dispensed onto wafer 8 and spun off at high velocity, it encounters the walls of the bowl 2. Low viscosity liquids, e.g., water, tend to back-splatter in fine droplets or mist. With the LMT in place, none of the liquid reaches the vacuum chuck 10, the vacuum chuck spindle 14, or the spindle bearing 16.

The LMT 4 is a circular part, having concentric grooves 18, spaced by concentric rings 19, drained through holes 20. The tops of the rings 19 on the LMT 4 is angled away from the spindle as shown to efficiently carry away droplets forming near or on the back side of the wafer 8. Thus, before droplets can accumulate on central regions of the back side of the wafer 8 o other small radius parts of the spinner, where centripetal force to effect spin-off is low, the droplets are caught...