Reducing particulates during semiconductor fabrication

• US 5,131,460 A
• Filed: 10/24/1991
• Issued: 07/21/1992
• Est. Priority Date: 10/24/1991
• Status: Expired due to Fees

• Current Assignee: Applied Materials Incorporated
• Original Assignee: Applied Materials Incorporated
• Inventors: Krueger, Gordon P.
• Primary Examiner(s): Schwadron, Martin P.
• Assistant Examiner(s): LEO, LEONARD R
• Application Number:
  US07/782,848
• Time in Patent Office: 271 Days
• Field of Search: 165/80.2, 165/80.3, 437/228, 437/248, 29/25.02, 118/50
• US Class Current: 165/80.2
• CPC Class Codes: C23C 14/541 Heating or cooling of the substrates
• CPC Class Codes: C23C 14/564 Means for minimising impurities in the coating chamber such as dust, moisture, residual gases
• CPC Class Codes: H01L 21/67109 mainly by convection

Abstract

A system for pumping down pressurized gas residing after shut-off in the piping use to provide a gas flow to facilitate backside wafer heating/cooling during the processing of a semiconductor wafer and including a valve selectable secondary piping line for equalizing on shutoff any pressure differential occurring in the primary gas flow line between the process chamber and the backside heating element. The secondary line runs from an opening in the process chamber wall to a tee-joint installed in the primary flow line immediately downstream of the final isolation valve in the primary line. A valve is installed in the secondary line and is operationally interlocked, in an inverse manner, with the isolation valve in the primary line such that when one valve is open the other valve is closed and vice versa.

Claims

1. In a processing system including a pressurized processing chamber into which a substrate with a surface to be processed may be disposed, means for heating/cooling the opposite surface of said substrate including a heat exchanger disposed immediately adjacent said opposite surface, and means for directing a flow of gas between said heat exchanger and said opposite surface, said means for directing of flow of as including a source of said gas, means forming a primary path for said gas from said source to said substrate, and first valve means for controlling the flow of said gas through said primary path, an improved means for heating/cooling said substrate, comprising:

means communicating with said primary path and forming a secondary path for said gas from said primary path to said processing chamber; and

second valve means disposed in said secondary path and operatively associated with said first valve means such that when said first valve means is open, said second valve means is closed and said gas flows from said source through said primary path means to said substrate, and when first valve means is closed said second valve means is open allowing gas contained in said primary path means downstream of said first valve means to flow through said secondary path means into said processing chamber.

2. In a processing system as recited in claim 1, wherein said first and second valve means are embodied in a single structure operative in two states such that in one state said gas is isolated from said secondary path means and flows from said source through said primary path means to said substrate and in the other state said gas flows from said primary path means downstream of said single structure through said secondary path means into said processing chamber.

3. A means for heating/cooling the backside of a semiconductive wafer during processing of the front side thereof in a processing chamber comprising:

means for heating/cooling the backside of the wafer including a heating/cooling plate disposed immediately adjacent the backside of the wafer;

means for directing a flow of gas between said plate and said wafer to improve the thermal transfer therebetween, said means for directing a flow of gas including;

a source of said gas,

means forming a primary path for said gas from said source to said wafer,

first valve means for controlling the flow of said gas through said primary path;

means communicating with said first path and forming a secondary path for said gas from a point downstream of said first valve means to said processing chamber; and

second valve means in said secondary path and operatively associated with said first valve means such that, when said first valve means is opened said second valve means is closed, said gas flows from said source through said primary path to said wafer, and when said first valve means is closed said second valve means is opened and gas contained in said primary path downstream of said first valve means is allowed to flow through said secondary path means into said processing chamber.

4. A means for heating/cooling the backside of a semiconductor wafer as recited in claim 3 wherein said first and second valve means are embodied in a single structure operative in two states such that in one state said gas is isolated from said secondary path and flows from said source through said primary path to said wafer, and in the other state said gas flows from said primary path downstream of said single structure through said secondary path into said processing chamber.