Chemical delivery systems and methods of delivery

• US 6,269,975 B2
• Filed: 05/11/2000
• Issued: 08/07/2001
• Est. Priority Date: 12/30/1998
• Status: Expired due to Term

• Current Assignee: Air Liquide Electronics US LP (Air Liquide SA)
• Original Assignee: Semco LLC
• Inventors: Forshey, Randy, Soberanis, David
• Primary Examiner(s): Bomberg, Kenneth
• Application Number:
  US09/568,926
• Publication Number:
  US 20010002026A1
• Time in Patent Office: 453 Days
• Field of Search: 137/403, 137/408, 222/53, 222/56, 222/58, 222/1
• US Class Current: 222/1
• CPC Class Codes: B01F 2101/2204 Mixing chemical components in generals in order to improve chemical treatment or reactions, independently from the specific application
• CPC Class Codes: B01F 2101/58 Mixing semiconducting materials, e.g. during semiconductor or wafer manufacturing processes
• CPC Class Codes: B01F 35/75 Discharge mechanisms
• CPC Class Codes: B01F 35/7543 using pneumatic pressure, overpressure or gas pressure in a closed receptacle or circuit system
• CPC Class Codes: B01F 35/881 by weighing, e.g. with automatic discharge
• CPC Class Codes: B67D 7/0238 utilising compressed air or other gas acting directly or indirectly on liquids in storage containers for dispensing beverages on draught B67D1/04
• CPC Class Codes: B67D 7/0272 specially adapted for transferring liquids of high purity
• CPC Class Codes: B67D 7/0283 specially adapted for transferring liquids of high purity
• CPC Class Codes: B67D 7/74 Devices for mixing two or more different liquids to be transferred coin-freed apparatus G07F13/06
• CPC Class Codes: C30B 25/14 Feed and outlet means for the gases; Modifying the flow of the reactive gases

Abstract

The present invention relates to chemical delivery systems and methods for delivery of liquid chemicals. In one embodiment, the present invention relates to systems having multi-reservoir load cell assemblies for delivering chemicals used in the semiconductor industry. In one embodiment, the present invention provides a multi-reservoir load cell assembly, including a controller, a buffer reservoir, a main reservoir, one or more load cells, coupled to the assembly and to the controller, operable to weigh the liquid in the reservoir(s), a plurality of supply lines, each supply line having a valve and connecting one of the supply containers to the main reservoir, and a gas and vacuum sources for withdrawing the liquid from the assembly when demanded by the controller and for refilling the assembly from the supply containers.

Claims

1. A method of liquid chemical delivery in a system comprising a multi-reservoir load cell assembly, including a main reservoir, a buffer reservoir, at least one load cell, and a logic device which triggers a refill sequence, comprising:

isolating the buffer reservoir from the main reservoir;

reducing pressure in the main reservoir to draw liquid chemical into the main reservoir;

weighing liquid chemical by the multi-reservoir load cell assembly;

supplying the main reservoir with inert gas; and

transporting liquid chemical from the main reservoir to the buffer reservoir.

2. A method of mixing a first liquid chemical with a second liquid chemical and delivering the mixture in a system comprising a multi-reservoir load cell assembly, including a main reservoir, a buffer reservoir, and a load cell, comprising:

isolating the buffer reservoir from the main reservoir;

supplying a first liquid chemical to the main reservoir until the multi-reservoir load cell assembly determines the main reservoir has a sufficient amount of the first liquid chemical;

supplying a second liquid chemical to the main reservoir until the multi-reservoir load cell assembly determines the main reservoir has a sufficient amount of the second liquid chemical;

mixing the first liquid chemical with the second liquid chemical; and

supplying mixture of the first liquid chemical and the second liquid chemical from the main reservoir to the buffer reservoir.

3. A method of precise non-pulsed liquid chemical delivery in a system comprising a multi-reservoir load cell assembly, including a main reservoir, a buffer reservoir, a load cell, comprising:

supplying pressurized gas to the main reservoir;

isolating the buffer reservoir from the main reservoir;

once the buffer reservoir is sealed, evacuating the main reservoir causing liquid chemical flow into the main reservoir until the load cell and the logic device determine the main reservoir is refilled with liquid chemical;

supplying the liquid chemical from the buffer reservoir without negative pressure or a difference in pressure;

once the main reservoir has refilled, stopping vacuum generation to the main reservoir and supplying low pressure gas to the main reservoir and to the buffer reservoir;

allowing the liquid chemical from the main reservoir to flow into the buffer reservoir; and

supplying high pressure gas to the main reservoir during and/or after liquid chemical flow from the main reservoir to the buffer reservoir.