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Low Pressure Liquid Dispense System

IP.com Disclosure Number: IPCOM000088418D
Original Publication Date: 1977-Jun-01
Included in the Prior Art Database: 2005-Mar-04
Document File: 2 page(s) / 45K

Publishing Venue

IBM

Related People

Cascio, SJ: AUTHOR [+3]

Abstract

Precision chemical dispensing is required in semiconductor processing specifically in the application of photoresist to the wafer surface. To date, designed equipment operates to dispense photoresist by using pressurized pots and electrical/pneumatic controls that dictate requirements for "pressure-safety and electrical-safety" when handling or dispensing flammable materials such as photoresists. The design of such a system is very costly when considering the expenses involved for testing design criteria and obtaining safety and insurance dependent approval to operate a high pressure dispensing system containing flammable chemicals.

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Low Pressure Liquid Dispense System

Precision chemical dispensing is required in semiconductor processing specifically in the application of photoresist to the wafer surface. To date, designed equipment operates to dispense photoresist by using pressurized pots and electrical/pneumatic controls that dictate requirements for "pressure-safety and electrical-safety" when handling or dispensing flammable materials such as photoresists. The design of such a system is very costly when considering the expenses involved for testing design criteria and obtaining safety and insurance dependent approval to operate a high pressure dispensing system containing flammable chemicals.

The present approach (see figure) utilizes a principle of low pressure (2-5 psi), positive displacement of flammable chemicals.

A repeated fixed volume of chemical is dispensed, depending upon the pressure applied (2-5 psi) to the internal collapsible bottle, that is relative to the wall thickness and flexibility of the bottle material and viscosity of the chemical. A fully collapsible bottle can also be used. Stainless steel pressure pots require an increased space allocation (packaging density) when placed in an automatic tool, compared to this dispense system which requires less packing space and hardware per unit volume of chemical to be used in the system.

If the outer jacket should burst, only N2 would leak from the system. Also, if the inner bottle containing the chemical should burst, N2 gas...