Electrostatic Substrate Cleaning for Particle Removal
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Solution Overview
Problem
Conventional methods for removing foreign materials from the bottom surface of substrates during plasma processing either contaminate the cleaning fluid, leading to potential contamination of the wafer surface, or cause damage to the substrate due to excessive plasma processing.
Innovation Solution
A substrate cleaning apparatus and method that utilizes an electrostatic field and gas flow to detach and remove foreign materials from the substrate's bottom surface without damaging it, employing a chamber with a mounting table, electrode, exhaust unit, and gas supply to create a space where electrostatic stress and gas flow effectively remove particles.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If wet cleaning using cleaning fluid is used to remove particles from the bottom surface of the wafer, then the particles can be removed, but the cleaning fluid becomes contaminated and may contaminate the wafer surface
Solution Approach 1:
The invention extracts and removes particles from the bottom surface of the wafer using a separate plasma processing step before the wafer is transferred to the next chamber. This extraction method avoids the need for wet cleaning that would contaminate the cleaning fluid and potentially the wafer surface, thereby resolving the contradiction between cleaning effectiveness and contamination prevention
Solution Approach 2:
The invention introduces a plasma environment as an intermediary medium to remove particles from the wafer bottom surface. The plasma acts as a mediator that can detach particles without direct contact with cleaning fluids, thus achieving effective cleaning while preventing contamination of both the cleaning medium and the wafer surface
2Manufacturing precision
If plasma processing is used to remove particles from the bottom surface of the wafer, then the particles can be removed, but the top surface of the wafer may be damaged due to excessive plasma processing
Solution Approach 1:
The invention applies plasma processing locally and selectively to the bottom surface of the wafer only. By directing plasma flux primarily at the bottom surface where particles are located, the treatment is concentrated where needed while minimizing exposure of the top surface to plasma, thus achieving effective particle removal without excessive damage to the substrate
Solution Approach 2:
The invention segments the plasma processing into distinct phases: a first plasma processing step that removes particles from the bottom surface, and a second plasma processing step that treats the top surface. This segmentation allows controlled particle removal from the bottom surface before the wafer is transferred, preventing both particle contamination and excessive damage while maintaining manufacturing precision
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
The method efficiently removes foreign materials from the substrate's bottom surface without damaging the substrate, preventing contamination and maintaining the integrity of the wafer surface.
Implementation Method 1
the substrate being attracted and held on the mounting table as a voltage is applied to the electrode
Implementation Method 2
while the space is formed, a voltage is applied to the electrode, the gas supply unit supplies a gas into the space and the exhaust unit exhausts the inside of the chamber
Implementation Method 3
the gas supply unit supplies a gas into the space and the exhaust unit exhausts the inside of the chamber
Data Source
AI summary
A substrate cleaning apparatus includes a chamber for accommodating a substrate; a mounting table, disposed in the chamber, for mounting thereon the substrate; an electrode disposed in the mounting table, the substrate being attracted and held on the mounting table as a voltage is applied to the electrode; an exhaust unit for exhausting the inside of the chamber; a separating unit for separating the mounting table and the substrate to form a space therebetween; and a gas supply unit for supplying a gas into the space. While the space is formed, voltages of different polarities are alternately applied to the electrode, the gas supply unit supplies a gas into the space and the exhaust unit exhausts the inside of the chamber. The substrate cleaning apparatus further includes a gas introduction unit for introducing a gas into the chamber while the chamber is depressurized and the space is formed.