Wafer Transfer Fluid with Charge-Forming Substance
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Solution Overview
Problem
The existing methods of transferring wafers in chemical mechanical polishing systems often result in local discharge damage due to the waterfall effect caused by water spray, leading to defects and non-uniform polishing.
Innovation Solution
Incorporating a charge-forming chemical substance into the fluid sprayed during wafer transfer to inhibit the waterfall effect, using a fluid with a gas or electrolyte that dissociates to produce electric charges, which reduces electrostatic discharge and minimizes contact between the wafer and the pedestal.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If water spray is used to assist wafer transfer, then contact between wafer and pedestal is reduced, but local discharge damage occurs due to waterfall effect
Solution Approach 1:
The patent converts the harmful waterfall effect into a beneficial floating effect by adding charge-forming chemical substances to the spray fluid. The fluid still provides the necessary lifting force to separate the wafer from the pedestal, but now also generates electric charges that prevent local discharge damage through charge neutralization.
Solution Approach 2:
The patent changes the chemical composition parameter of the spray fluid by incorporating charge-forming chemical substances. This modification transforms the fluid from causing harmful electrostatic discharge to generating beneficial charges that prevent local discharge damage, while maintaining the fluid's primary function of reducing contact.
2Productivity
If conventional water spray is used, then wafer transfer is assisted, but electrostatic discharge causes defects and non-uniform polishing
Solution Approach 1:
The charge-forming chemical substances act as intermediaries between the water spray and the wafer surface. These substances generate electric charges in the fluid that serve as a mediator to prevent direct electrostatic discharge onto the wafer, thereby protecting the wafer while maintaining transfer efficiency.
Solution Approach 2:
The patent transforms the harmful electrostatic discharge into a protective mechanism by using charge-forming chemical substances. The same waterfall effect that previously caused damage now generates charges that prevent local discharge, converting a harmful factor into a protective one while maintaining transfer productivity.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Prevents local discharge damage and improves yield by neutralizing charges and reducing friction between the wafer and the pedestal, ensuring more accurate and uniform polishing.
Implementation Method 1
A fluid is sprayed from the spray orifice onto the first surface simultaneously with the disposition of the wafer above the pedestal. The fluid contains a charge-forming chemical substance dissolved therein.
Implementation Method 2
A fluid is sprayed from the spray orifice onto the first surface simultaneously with the disposition of the wafer above the pedestal to avoid a contact of the first surface with the pedestal.
Data Source
AI summary
A method of transferring a wafer is disclosed. The method comprises providing a pedestal and at least one spray orifice extending through the pedestal; disposing a wafer above the pedestal using a first robot, wherein the wafer has a first surface and a second surface, the first surface faces the pedestal, a fluid is sprayed onto the first surface simultaneously to avoid a contact of the first surface with the pedestal, and the fluid contains a charge-forming chemical substance dissolved therein; and taking the wafer using a robot for delivery. Due to the charge-forming chemical substance dissolved in the fluid, the waterfall effect to cause discharge damage on the wafer is avoided in the spraying of the fluid.