Optical Trapping for Pellicle Particle Removal
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Solution Overview
Problem
The semiconductor industry faces challenges in removing particles from pellicle membranes and photomasks, which can lead to degradation of lithographically transferred patterns and reduced wafer yield.
Innovation Solution
The use of optical trapping technology to efficiently remove particles from pellicle membranes and photomasks, employing vertical, horizontal, and tilted optical traps in conjunction with gravitational forces to mitigate particle accumulation and damage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If traditional particle removal methods are used, then manufacturing process complexity increases, but particle removal effectiveness deteriorates
Solution Approach 1:
The patent replaces traditional mechanical particle removal methods (such as physical cleaning, ultrasonic cleaning, or chemical etching) with an optical trapping system that uses focused laser beams to capture and remove particles. This substitution achieves effective particle removal while avoiding the complexity and potential damage associated with mechanical or chemical methods.
Solution Approach 2:
The patent introduces an optical trap as an intermediary mechanism between the particle and the removal system. The optical trap serves as a mediator that captures particles through optical forces and transports them to a collection point, enabling particle removal without direct mechanical contact or complex chemical processes.
2Productivity
If aggressive particle removal techniques are applied, then particle removal efficiency improves, but damage to pellicle membranes and photomasks increases
Solution Approach 1:
The patent replaces aggressive mechanical or chemical particle removal techniques with optical trapping that uses radiation pressure to capture and remove particles. This method achieves high particle removal efficiency while being gentler on the pellicle membranes and photomasks, avoiding the damage caused by traditional aggressive methods.
Solution Approach 2:
The optical trapping system uses the particles' own optical properties (refractive index, size) to generate the forces needed for their removal. The focused laser beam creates optical gradients that naturally attract and hold particles without requiring external mechanical contact or harsh chemicals, enabling efficient yet damage-free particle removal.
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
This method effectively removes particles from sensitive areas, improving the cleanliness and fidelity of pattern transfer, thereby enhancing wafer yield and minimizing damage to pellicle membranes, frames, and photomask substrates.
Implementation Method 1
Light beams are generated to form an optical trap. The optical trap extends in a direction perpendicular to the pellicle membrane. The particle is removed from the pellicle membrane by the optical trap.
Implementation Method 2
employing vertical, horizontal, and tilted optical traps in conjunction with gravitational forces to mitigate particle accumulation and damage
Data Source
AI summary
The present disclosure provides a method for removing particles. The method includes: receiving a pellicle including a pellicle membrane, wherein a particle is disposed on the pellicle membrane; passing a light beam through an object lens, wherein the light beam is focused on a focal region in front of the pellicle membrane by the object lens, and the particle is attracted to be trapped at the focal region; and removing the particle from the pellicle membrane at the focal region.