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Gas Cabinet - Automated Back-up System

IP.com Disclosure Number: IPCOM000019374D
Publication Date: 2003-Sep-12
Document File: 3 page(s) / 209K

Publishing Venue

The IP.com Prior Art Database

Abstract

An Automated Backup System (ABS) was developed in an effort to reduce the operating and initial capital costs for a semiconductor fabrication facility, while still retaining uninterrupted gas supply. By reducing the total number of cabinets that need to be exhausted, the operating costs associated with cabinet ventilation can be reduced. Capital costs are lower due to a combination of the reduced size of the ventilation/scrubber system as well as the reduction in the number of cabinets that need to be purchased.

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Gas Cabinet - Automated Back-up System

Problem Definition

An Automated Backup System (ABS) was developed in an effort to reduce the operating and initial capital costs for a semiconductor fabrication facility, while still retaining uninterrupted gas supply. By reducing the total number of cabinets that need to be exhausted, the operating costs associated with cabinet ventilation can be reduced. Capital costs are lower due to a combination of the reduced size of the ventilation/scrubber system as well as the reduction in the number of cabinets that need to be purchased.

Each two-cylinder cabinet can supply two tools (standard auto-crossover cabinets only supply one tool). If 'x' is the number of standard auto-crossover cabinets required for a given installation, one can meet the installation’s requirements with (x/2+1) systems using ABS (the '+1' is the backup, i.e. the standard auto-crossover system).

There is a limit, based on flow requirements, to the number of systems that can function on an ABS loop. Depending on the flow rate and number of tools, it may be necessary to limit the number of cylinders which the backup auto-crossover supplies at any given time.

Process Description

ABS is designed to reduce the number of systems required for a given number of tools while still maintaining crossover functionality. Crossover from primary to backup is automatically initiated by three alarm conditions: (1) very low cylinder weight, (2) very low process cylinder pressure, or (3) very low process delivery pressure.

The ABS flowsheet is given in Figure 1. When crossover occurs, V-3 (process outlet on primary) is closed and V-26 is opened on t...