Browse Prior Art Database

Temperature Control of Product Locations in a Clean Room Environment

IP.com Disclosure Number: IPCOM000100797D
Original Publication Date: 1990-Jun-01
Included in the Prior Art Database: 2005-Mar-16
Document File: 2 page(s) / 51K

Publishing Venue

IBM

Related People

Marvell, GA: AUTHOR

Abstract

By automatic adjustment of the relative rate of vertical air flow downward in product and tool regions versus non-sensitive regions of a clean room, the temperature of the product and sensitive tools is controlled to within a few hundredths of a degree Celsius. Changes in thermal conditions detected in several areas simultaneously are corrected by conditioned supply air temperature change.

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Temperature Control of Product Locations in a Clean Room Environment

       By automatic adjustment of the relative rate of vertical
air flow downward in product and tool regions versus non-sensitive
regions of a clean room, the temperature of the product and sensitive
tools is controlled to within a few hundredths of a degree Celsius.
Changes in thermal conditions detected in several areas
simultaneously are corrected by conditioned supply air temperature
change.

      The figure is a cross section of a clean room containing tool
10, e.g., an exposure tool, product storage area 12, and product load
station 14.  Temperature detectors A, B, C, and D are placed near
product height and below HEPA filter plenums a, b, c, and d which
supply air downward.  Air is returned under raised floor 16, through
return air conduit 18 and mixed with supply air conditioned by heater
20 and/or cooling coil 22 to be supplied through conduit 24 to HEPA
filter plenums a, b, c, and d.  Air valves 26 can adjust air flow
independently to each HEPA plenum typically over a range of plus or
minus 5% of a nominal flow rate of 100 feet per minute.  Thus, local
temperature under a given plenum may be controlled by a flow rate
change without losing vertical laminar flow integrity.

      When a single sensor indicates significant deviation from
temperature setpoint, the appropriate air valve is adjusted.  To hold
total room air flow demand in conduit 24 nearly constant, a
compensating a...