Browse Prior Art Database

Optimized Tool Location for Semiconductor Factories

IP.com Disclosure Number: IPCOM000008301D
Original Publication Date: 2002-Jun-04
Included in the Prior Art Database: 2002-Jun-04
Document File: 3 page(s) / 71K

Publishing Venue

Motorola

Related People

Larry E. Frisa: INVENTOR

Abstract

Automated transport systems are often used in advanced semiconductor manufacturing factories (Fabs) to transport wafers to/from process tools and/or storage racks. While the initial cost of these systems are large, they are important for reducing overall operating costs since they speed up cycle time and reduce misprocessing. The use of overhead transportation (OHT) systems is especially useful in lowering operation costs of 300mm Fabs. The industry standard for 300mm processing equipment is to include one or more loadports where wafers can be lowered from an OHT system, automatically processed through the tool, then raised up to the OHT and moved to the next process tool.

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Optimized Tool Location for Semiconductor Factories

Larry E. Frisa          

Introduction

Automated transport systems are often used in advanced semiconductor manufacturing factories (Fabs) to transport wafers to/from process tools and/or storage racks.  While the initial cost of these systems are large, they are important for reducing overall operating costs since they speed up cycle time and reduce misprocessing.  The use of overhead transportation (OHT) systems is especially useful in lowering operation costs of 300mm Fabs.  The industry standard for 300mm processing equipment is to include one or more loadports where wafers can be lowered from an OHT system, automatically processed through the tool, then raised up to the OHT and moved to the next process tool. 

A new concept in the factory layout of processing tools so as to simplify the floor plan by eliminating the traditional bay between process tools and by using fewer overhead tracks to access the same number of process tools is presented in this paper.

Background

The standard layout for OHT systems is that of a traditional “bay between the tools” configuration, illustrated in Figure 1.  This configuration is used in older, non-automated Fabs so that operators can manually load wafers onto process tools and run the processing from the controls on the front of each tools.  As the semiconductor industry has matured, equipment manufactures have placed control screens in locations other than the front of their tools.  Also, 300mm equipment standards require all tools to be able to recognize the arrival of specific container of wafers and be able to run the process program automatically.  Thus with automation of wafer arrival from an OHT system and tool operation from a remote central computer, the need for a physical bay between tools is minimal.

When a bay type design is used for OHT systems, care must be taken to make sure that the front of the wafer transportation pod, usually a Front Opening Universal Pod (FOUP) in the case of 300mm tools, faces the front of the tool when it’s lowered onto the loadport (see Figure 1).

 

The Improvement Concept

The layout of a Fab can improve by eliminating the processing bay between tools as seen in Figure 2.  The main advantage to this type of layout is the cost savings.  By moving process tools closer together, the same number of tools can be placed within a much smaller cleanroom footprint.  Also, the same overhead track can be used for all tools that face each other, eliminating the need of two tracks for the same number of tools.  Since 300mm load ports are typically a shelf design with space between the underside of the loadport and the floor, there would be enough space under the loadport for tool maintenance and repair access.

The main issue with this type of layout is that in order to be processed, FOUPs need...