Unevenness Detection via Interference Fringes for Groove Verification
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Solution Overview
Problem
Current devices cannot accurately detect the three-dimensional shape or state of processed grooves and grinding unevenness on workpieces, limiting the verification of processing conditions in semiconductor manufacturing.
Innovation Solution
An unevenness detecting device using a pulsed illuminating light source, converging lenses, a half-silvered mirror, chromatic aberration lens, mask, diffraction grating, and imaging element to generate two-dimensional and three-dimensional sectional shapes of workpieces, allowing precise detection of processed states.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional imaging means is used to detect processed grooves, then a two-dimensional image of the top surface can be obtained, but the three-dimensional shape, depth, and processed state cannot be verified
Solution Approach 1:
The patent applies dimensionality change by using optical interference to convert three-dimensional surface information into two-dimensional interference fringe patterns. The unevenness detecting device captures interference fringes that encode depth and shape information, allowing three-dimensional verification through two-dimensional imaging. This resolves the contradiction by enabling 3D measurement capability while using 2D imaging technology.
2Measurement precision
If conventional imaging means is used for ground workpiece surfaces, then the top surface can be imaged, but the unevenness of grinding traces cannot be verified
Solution Approach 1:
The patent uses an intermediary approach by introducing reference light as a mediator between the workpiece surface and the imaging system. The reference light interferes with the reflected light from the workpiece, creating interference fringes that encode surface unevenness information. This intermediary mechanism enables precise unevenness detection without requiring complex direct measurement systems.
3Productivity
If two-dimensional imaging is used for processed grooves, then top surface detection is possible, but processing condition verification cannot be performed accurately
Solution Approach 1:
The patent implements feedback by using the captured interference fringe patterns to verify processing conditions and provide information for adjusting subsequent processing. The unevenness detecting device captures interference fringes, processes them to extract surface shape information, and feeds this information back to verify whether processing conditions achieved the desired groove shape and depth, enabling continuous process optimization.
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 accurate verification of processed states, enabling precise adjustment of processing conditions for laser processing, cutting, and grinding, improving the quality of semiconductor manufacturing.
Implementation Method 1
a pulsed illuminating light source emitting light having a predetermined wavelength range
Implementation Method 2
a first condensing lens condensing return light reflected by the workpiece retained by the workpiece holding means and passed through the chromatic aberration lens and the half-silvered mirror
Implementation Method 3
a diffraction grating performing light separation so as to correspond to wavelengths of the return light converged by the second converging lens
Data Source
AI summary
An unevenness detecting device includes: a pulsed illuminating light source emitting light having a predetermined wavelength range; a first condensing lens condensing return light reflected by a workpiece held on a chuck table and passed through a chromatic aberration lens and a half-silvered mirror; a mask disposed at the position of a focal point of the first condensing lens, the mask passing only the condensed return light; a diffraction grating performing light separation so as to correspond to the wavelengths of the return light; a second condensing lens condensing the return light resulting from the light separation by the diffraction grating; and an imaging element disposed at the position of a focal point of the second condensing lens.