Immersion Nozzle Cleaning for Semiconductor Substrates
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Solution Overview
Problem
Conventional cleaning methods for semiconductor substrates often damage small features due to high energy requirements, as they rely on cavitation and kinetic forces that are difficult to control, especially when dealing with residual particles in high-density dies.
Innovation Solution
A cleaning system that uses an immersed stream or spray nozzle with incompressible fluids to remove particles from semiconductor substrates, where a stream of second incompressible fluid is directed onto the substrate surface, minimizing turbulence and cavitation, and the first incompressible fluid supports the substrate to prevent feature damage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional spray or megasonic cleaning methods are used to remove residual particles, then particle removal effectiveness is improved, but feature damage increases due to uncontrolled cavitational and kinetic forces
Solution Approach 1:
The patent changes the physical state parameter of the cleaning fluid from compressible (gas) to incompressible (liquid), which fundamentally alters the cleaning mechanism from cavitation-based to hydrodynamic-based, thereby removing harmful cavitational forces while maintaining particle removal effectiveness
Solution Approach 2:
The patent replaces the mechanical cavitation system (megasonic transducers creating bubble collapse) with a hydrodynamic flow system (immersed nozzle creating controlled liquid stream), substituting uncontrolled cavitational forces with controlled hydrodynamic forces that are less damaging to features
2Productivity
If high energy spray is used to remove particles from small features, then particle removal increases, but the energy required exceeds the damage threshold for small surface features
Solution Approach 1:
The patent changes the fluid compressibility parameter from compressible to incompressible, enabling effective cleaning at lower energy levels by utilizing hydrodynamic pressure and flow rather than high-velocity gas impact and cavitation
Solution Approach 2:
The patent introduces an immersed nozzle as an intermediary device that operates below the fluid surface, using the surrounding liquid medium to cushion and control the cleaning action, thereby reducing the energy required compared to air-based spray methods
3Manufacturing precision
If compressible fluid spray is used for cleaning, then particle removal is achieved, but unpredictable pressure differentials cause adverse effects on substrate regions
Solution Approach 1:
The patent changes the fluid compressibility from compressible to incompressible, which eliminates the formation of pressure differentials and amalgam mixes, resulting in uniform hydrodynamic pressure distribution across the substrate surface and improved process controllability
Solution Approach 2:
The patent achieves homogeneous cleaning conditions by using incompressible fluid that maintains uniform pressure and density throughout the cleaning zone, eliminating the heterogeneous pressure zones and fluid amalgams that occur with compressible fluid spray
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
Effectively removes particles and residue from semiconductor substrates without causing unacceptable damage to the features, reducing process time and allowing for thorough cleaning with fewer passes, as the use of incompressible fluids maintains a stable pressure gradient and prevents compressible fluid accumulation.
Implementation Method 1
A stream of a second incompressible fluid is directed onto the substrate surface, minimizing turbulence and cavitation
Implementation Method 2
the first incompressible fluid supports the substrate to prevent feature damage
Implementation Method 3
A stream of a second incompressible fluid is directed onto the substrate surface, minimizing turbulence and cavitation
Data Source
AI summary
Several methods of removing contaminant particles from a surface of a substrate are disclosed herein. In one embodiment, the method includes directing an incompressible fluid spray onto a surface of a substrate to remove contaminant particles from the surface. In an embodiment, the surface of the substrate and the nozzle are both immersed in an incompressible fluid. The fluid can flow across the surface of the substrate to remove the contaminant particles from the area. The fluid spray can be positioned normal to the substrate surface, or can be positioned at an angle relative to the substrate surface.