Optical Transformation Module for Semiconductor Wafer Inspection
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Solution Overview
Problem
Conventional angle scatterometers suffer from high light losses and slow incidence angle adjustment, leading to inefficient defect detection on semiconductor wafers, which reduces productivity.
Innovation Solution
An optical transformation module with a rotating grating that adjusts the incidence angle and position of a parallel light beam by changing its wavelength, combined with a light generator and lens array, to enhance defect detection efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a space filter is used to incident light at various angles, then defect detection capability is improved, but light losses increase greatly
Solution Approach 1:
The invention extracts and removes the space filter component from the optical path. By eliminating this component, the system achieves multiple incidence angles through alternative means (optical transformation module) without suffering from the light losses that occur when light passes through the space filter
Solution Approach 2:
The invention introduces an optical transformation module as an intermediary between the light source and the wafer surface. This module transforms the parallel light beam to achieve various incidence angles and positions without requiring the light to pass through a space filter, thereby maintaining light intensity while achieving the desired angular diversity for defect detection
2Adaptability or versatility
If a space filter is used to adjust incidence angle, then angular diversity is improved, but change speed of incidence angle becomes very slow
Solution Approach 1:
The invention replaces the mechanical space filter system with an optical transformation module that uses optical principles (refraction, reflection, or diffraction) to achieve rapid angular transformation. This substitution eliminates the mechanical limitations and slow response time associated with rotating or moving physical filters
Solution Approach 2:
The optical transformation module enables dynamic and rapid adjustment of incidence angles through optical means. The system can quickly transform the light beam angle in response to detection requirements, providing real-time angular diversity without the inertia and speed limitations of mechanical filter systems
3Measurement precision
If various incidence angles are used to inspect the whole surface, then detection thoroughness is improved, but inspection time increases significantly
Solution Approach 1:
The invention enables continuous angular transformation of the light beam across the wafer surface. The optical transformation module continuously adjusts the incidence angle and position as the beam scans across the surface, allowing all areas to be inspected with optimal angles simultaneously rather than sequentially, thereby maintaining thorough detection while reducing total inspection time
Solution Approach 2:
The invention adds the dimension of spatial-position-dependent angular transformation. Instead of uniformly applying one angle or sequentially changing angles across the entire surface, the system transforms the incidence angle according to the spatial position on the wafer, enabling each region to be inspected at its optimal angle in a single pass
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 solution significantly reduces light losses and increases detection efficiency, allowing for faster scanning of semiconductor wafers and improved productivity in defect inspection.
Implementation Method 1
a rotating grating positioned on a path of the parallel light beam and rotatable by a predetermined rotation angle such that the parallel light beam is transformed according to the wavelength of the parallel light beam and the rotation angle of the rotating grating to have a desired incidence angle and a desired incidence position onto the surface of the inspection object
Implementation Method 2
a light generator generating a parallel light beam to be incident onto a surface of an inspection object and changing a wavelength of the parallel light beam
Data Source
AI summary
An optical transformation module includes a light generator generating a parallel light beam to be incident onto a surface of an inspection object and changing a wavelength of the parallel light beam, and a rotating grating positioned on a path of the parallel light beam and rotatable by a predetermined rotation angle such that the parallel light beam is transformed according to the wavelength of the parallel light beam and the rotation angle of the rotating grating to have a desired incidence angle and a desired incidence position onto the surface of the inspection object.