Wafer Cleaning Jets to Prevent Semidry Particle Residue
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Solution Overview
Problem
The roller-type substrate cleaning device is limited by low wafer rotation speed, leading to increased cleaning time and incomplete removal of particles due to semidry surfaces and insufficient centrifugal force, resulting in residual particles on the substrate.
Innovation Solution
A substrate cleaning method and apparatus that uses holding rollers to rotate the substrate while delivering a two-fluid jet and a fan-shaped jet of liquid from separate nozzles, oriented to avoid collision and ensure uniform coverage, with the fan-shaped jet positioned to prevent semidryness and effectively flush out particles.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If roller-type cleaning device is used to avoid liquid scattering, then liquid scattering is prevented, but wafer rotation speed is limited to low speed
Solution Approach 1:
The cleaning process is segmented into two distinct stages: first, particle removal using two-fluid jet while wafer rotates at low speed; second, particle flushing using fan-shaped liquid jet while wafer rotates at high speed. This segmentation allows each stage to operate at optimal speeds without compromising the other stage's effectiveness.
Solution Approach 2:
The two-fluid jet cleaning is performed as a preliminary action to remove particles from the wafer surface before the high-speed rotation and fan-shaped jet flushing. This preliminary particle removal prevents liquid scattering during the subsequent high-speed operation.
2Productivity
If wafer rotation speed is increased to improve cleaning efficiency, then cleaning efficiency is improved, but particles remain on semidry substrate
Solution Approach 1:
The cleaning process uses periodic action by alternating between low-speed rotation with two-fluid jet (for particle removal) and high-speed rotation with fan-shaped jet ( for particle flushing). This periodic switching ensures both efficient cleaning and complete particle removal without semidry conditions.
Solution Approach 2:
The system dynamically changes operational parameters (rotation speed and liquid delivery mode) between two distinct states: low-speed with two-fluid jet and high-speed with fan-shaped jet. This parameter change allows optimization of both cleaning efficiency and particle removal completeness.
3Manufacturing precision
If two-fluid jet is used to remove particles, then particles are lifted from surface, but substrate becomes semidry and particles remain
Solution Approach 1:
The fan-shaped liquid jet acts as an intermediary that delivers additional liquid to the substrate after particle removal. This intermediary action replenishes the liquid film on the semidry substrate, enabling complete particle removal and preventing residual particles.
Solution Approach 2:
The fan-shaped jet delivers liquid continuously during high-speed wafer rotation to maintain substrate wetness. This continuous liquid delivery ensures that particles are fully flushed from the substrate surface without leaving semidry conditions that would trap particles.
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 ensures thorough cleaning by maintaining substrate wetness and efficiently removing particles lifted by the two-fluid jet, preventing semidryness and enhancing cleaning efficiency.
Implementation Method 1
delivering a two-fluid jet from a two-fluid jet nozzle to a surface of the substrate, the two-fluid jet being composed of a mixture of a first liquid and a gas
Implementation Method 2
delivering a two-fluid jet from a two-fluid jet nozzle to a surface of the substrate
Implementation Method 3
delivering a fan-shaped jet of a second liquid from a spray nozzle to the surface of the substrate to form a flow of the second liquid on the surface of the substrate
Implementation Method 4
rotating the substrate about its central axis by rotating the holding rollers about their respective central axes
Data Source
Figure 1
Figure 2~3
Figure 4A~5
AI summary
The present invention relates to a substrate cleaning method and a substrate cleaning apparatus for cleaning a substrate, such as a wafer. The substrate cleaning method includes: holding a periphery of a substrate (W) with holding rollers (6); rotating the substrate (W) about its central axis by rotating the holding rollers (6) about their respective central axes; delivering a two-fluid jet from a two-fluid jet nozzle (2) to a surface of the substrate (W) while moving the two-fluid jet nozzle (2) in a radial direction of the substrate (W), the two-fluid jet (2) being composed of a mixture of a first liquid and a gas; and when the two-fluid jet is being delivered to the surface of the substrate (W), delivering a fan-shaped jet of a second liquid from a spray nozzle (3) to the surface of the substrate (W) to form a flow of the second liquid on the surface of the substrate (W). The fan-shaped jet is located away from the two-fluid jet.