Planar Spectral Film Thickness Mapping for In-Plane Uniformity
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Solution Overview
Problem
Existing film thickness measurement methods, such as point sensors and line scans, are time-consuming and inefficient for determining in-plane uniformity, leading to prolonged process times and reduced productivity in semiconductor manufacturing.
Innovation Solution
A film thickness measuring apparatus that uses a light irradiation unit to irradiate an object with light in a planar shape, an optical element with wavelength-dependent transmittance and reflectance to separate light, and an imaging unit to estimate film thickness based on wavelength information, allowing for high-speed measurement of in-plane film thickness distribution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If point sensor or line scan is used to measure film thickness, then measurement accuracy is maintained, but measurement time becomes long
Solution Approach 1:
The patent transitions from one-dimensional point/line scanning to two-dimensional planar illumination with spectral decomposition. By illuminating the entire measurement area with broadband light and using a spectrometer to resolve wavelengths spatially, the system achieves simultaneous multi-point measurement across the film surface, reducing measurement time while maintaining accuracy through spectral analysis of reflected light intensity ratios at different wavelengths.
Solution Approach 2:
The patent replaces mechanical scanning systems (point sensor moving across the surface or line scan moving sequentially) with a stationary planar illumination system combined with spectral decomposition. The spectrometer optically separates wavelengths to create spatial encoding of depth information, eliminating mechanical movement and enabling parallel measurement of multiple points simultaneously.
2Manufacturing precision
If in-plane film thickness distribution is measured point by point, then comprehensive coverage is achieved, but productivity deteriorates
Solution Approach 1:
The system uses planar broadband illumination combined with spectral decomposition to achieve simultaneous multi-point measurement across the entire film surface. The spectrometer spatially resolves different wavelengths, creating a mapping between wavelength and depth information that allows comprehensive in-plane uniformity assessment without sequential scanning, thereby maintaining manufacturing precision while dramatically improving productivity.
Solution Approach 2:
The patent merges multiple measurement functions into a single integrated system: planar illumination provides broad spatial coverage, the film surface reflects the illumination, and the spectrometer simultaneously captures spectral information from multiple spatial locations. This combination enables comprehensive in-plane uniformity assessment across the entire measurement area in a single measurement cycle, eliminating the need for sequential point-by-point scanning.
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
Enables rapid and accurate estimation of film thickness across a surface, reducing measurement time from hours to seconds while maintaining high accuracy, and facilitating in-line integration in manufacturing processes.
Implementation Method 1
an optical element having a transmittance and a reflectance changing according to wavelengths in a predetermined wavelength range, the optical element being configured to separate light from the object by transmitting and reflecting the light
Implementation Method 2
an imaging unit configured to photograph light separated by the optical element
Implementation Method 3
an analysis unit configured to estimate a film thickness of the object based on a signal from the imaging unit photographing light, in which the light irradiation unit emits light having a wavelength included in the predetermined wavelength range of the optical element
Data Source
AI summary
A film thickness measuring apparatus includes a light irradiation unit configured to irradiate an object with light in a planar shape, an optical element having a transmittance and a reflectance changing according to wavelengths in a predetermined wavelength range, the optical element being configured to separate light from the object by transmitting and reflecting the light, an imaging unit configured to photograph light separated by the optical element, and an analysis unit configured to estimate a film thickness of the object based on a signal from the imaging unit photographing light, in which the light irradiation unit emits light having a wavelength included in the predetermined wavelength range of the optical element.