Browse Prior Art Database

Trolley Drive Mechanism

IP.com Disclosure Number: IPCOM000039890D
Original Publication Date: 1987-Aug-01
Included in the Prior Art Database: 2005-Feb-01
Document File: 1 page(s) / 11K

Publishing Venue

IBM

Related People

Lupul, FT: AUTHOR [+3]

Abstract

A spring-loaded drive mechanism for a trolley dome assembly is used in processing semiconductor wafers. It requires no adjustment and replaces a mechanism which required frequent adjustments to prevent wafer damage. The trolley assembly originally used requires a precise preload adjustment. This is critical for the proper operation of the dome evaporators in which the wafers are processed. Wear, along with operating temperatures, affects this adjustment. If the adjustment is loose, the drive dog contacts the center hub and pushes the loaded dome with a jarring force severe enough to displace the wafers from their nesting position. This causes misalignment of the wafers inside the mask tooling dome.

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Trolley Drive Mechanism

A spring-loaded drive mechanism for a trolley dome assembly is used in processing semiconductor wafers. It requires no adjustment and replaces a mechanism which required frequent adjustments to prevent wafer damage. The trolley assembly originally used requires a precise preload adjustment. This is critical for the proper operation of the dome evaporators in which the wafers are processed. Wear, along with operating temperatures, affects this adjustment. If the adjustment is loose, the drive dog contacts the center hub and pushes the loaded dome with a jarring force severe enough to displace the wafers from their nesting position. This causes misalignment of the wafers inside the mask tooling dome. If the adjustment is too tight, the dome drive mechanism shudders and vibrates, displacing the wafers and causing misalignment. Here, a spring- loaded rigid plastic cylinder is held in place by a keeper plate. The mechanism is fitted through the trolley body and applies a constant resistance to the center hub, thereby eliminating the need for adjustments. As part of the modification, a stainless steel bearing spacer is also replaced with a ring made of a tetrafluoroethylene fluorocarbon polymer to minimize the possibility of binding.

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