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Browse Prior Art Database

Wafer Handling System

IP.com Disclosure Number: IPCOM000078466D
Original Publication Date: 1973-Jan-01
Included in the Prior Art Database: 2005-Feb-26
Document File: 2 page(s) / 48K

Publishing Venue

IBM

Related People

Brittain, JE: AUTHOR [+3]

Abstract

This wafer handling system eliminates human contamination and error in the loading and unloading of process carriers with semiconductor wafers. Two vertically positionable process boat elevators 10 and 12 (Fig. 2) hold wafer stacking boats with a horizontal gas track system 14, which provides transportation for the wafers between the two elevators. Wafers pass over the track via parallel pairs of rows of bidirectional ports, so that transfer can be selected in either direction. The wafer handler employs a fully interlocked, servo control system consisting of two servo motors M1 and M2 which drive lead screws and two positional feedback sensors 20 and 22.

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Wafer Handling System

This wafer handling system eliminates human contamination and error in the loading and unloading of process carriers with semiconductor wafers. Two vertically positionable process boat elevators 10 and 12 (Fig. 2) hold wafer stacking boats with a horizontal gas track system 14, which provides transportation for the wafers between the two elevators. Wafers pass over the track via parallel pairs of rows of bidirectional ports, so that transfer can be selected in either direction. The wafer handler employs a fully interlocked, servo control system consisting of two servo motors M1 and M2 which drive lead screws and two positional feedback sensors 20 and 22.

The electronics and controls necessary to opeate the system are shown in Fig. 1. The input/output logic 24 receives all logic inputs into the unit, except those from photocell amplifiers and all lamp drivers. Input/Output control logic 26 receives the logic inputs from the photocells CRE1 - CRE4 and performs all sequencing involved. CRE1 - CRE4 are arranged in pairs at each end of track 14 so as to indicate the presence or absence of a wafer in the boat at the transfer position, and also that the wafers are clear of the track at each end. The position counters 28 and 30 count pulses received from 26 and supply a decimal output. The field-effect transistor (FET) switches 32 and 34 receive the decimal signals and trigger a FET.

The FETs open to allow the desired command voltage to appear at th...