Scatterfield Microscopy Phase Modulation for Semiconductor Inspection
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Solution Overview
Problem
Conventional microscopic imaging techniques, such as SEM and AFM, are inadequate for real-time in-situ analysis in semiconductor fabrication due to resolution limitations and potential specimen damage, while scatterfield microscopy offers superior resolution and speed but requires complex precision control mechanisms.
Innovation Solution
A scatterfield microscopical measuring apparatus integrating a spatial light modulator with phase modulation ability and an immobile optical imaging device, allowing for variable projection angles without precision position control, simplifying the inspection process and enhancing integration with other modules.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional microscopy techniques (SEM, AFM) are used to achieve sufficient resolution, then measurement precision is improved, but device complexity and potential specimen damage increase
Solution Approach 1:
The patent replaces mechanical positioning systems with optical phase modulation. Instead of physically moving the sample or optical components to achieve different illumination angles, the invention uses a spatial light modulator to modulate the phase of light waves, creating variable angle illumination through optical field control. This substitution of mechanical systems with optical field control reduces device complexity while maintaining measurement precision.
2Measurement precision
If scatterfield microscopy with precision position control is used to achieve variable projection angles, then measurement precision is improved, but device complexity increases
Solution Approach 1:
The patent replaces precision mechanical positioning systems with optical phase modulation. Instead of physically moving the sample or optical components to achieve different illumination angles, the invention uses a spatial light modulator to modulate the phase of light waves, creating variable angle illumination through optical field control. This substitution of mechanical systems with optical field control reduces device complexity while maintaining measurement precision.
Solution Approach 2:
The patent changes the control parameter from mechanical position to optical phase. By modulating the phase of the illumination light across different spatial locations using a spatial light modulator, the system achieves variable projection angles without mechanical movement. This parameter change from position control to phase control simplifies the device architecture while maintaining the ability to achieve precise angular illumination.
3Measurement precision
If AFM is used for internal inspection, then measurement precision is improved, but productivity decreases due to slow inspection speed
Solution Approach 1:
The patent enables continuous, non-contact optical inspection by eliminating the need for mechanical scanning. The scatterfield microscopy technique uses optical field modulation to illuminate the sample from multiple angles simultaneously, allowing for rapid data acquisition without the slow mechanical movement required by AFM. This continuous optical measurement process dramatically improves inspection speed while maintaining precision.
4Measurement precision
If SEM is used for surface inspection, then measurement precision is improved, but adaptability decreases due to inability to inspect internal structures
Solution Approach 1:
The patent creates a universal inspection system that can handle both surface and internal structure inspection. The scatterfield microscopy technique uses optical scattering information from the sample, which contains information about both surface morphology and internal structures. By analyzing the scattering patterns generated through variable angle illumination, the system achieves multi-functional inspection capability without requiring different specialized instruments.
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 efficient, high-resolution, and stable in-situ inspection of semiconductor samples by projecting a light beam at variable angles, overcoming the limitations of conventional microscopy and facilitating real-time process control without the need for complex positioning mechanisms.
Implementation Method 1
a spatial light modulator with phase modulation ability
Implementation Method 2
form a first beam focusing on the back focal plane
Implementation Method 3
project on the sample where it is reflected back as a second beam focusing on the back focal plane
Data Source
AI summary
The present invention provides a scatterfield microscopical measuring method and apparatus, which combine scatterfield detecting technology into microscopical device so that the microscopical device is capable of measuring the sample whose dimension is under the limit of optical diffraction. The scatterfield microscopical measuring apparatus is capable of being controlled to focus uniform and collimated light beam on back focal plane of an objective lens disposed above the sample. By changing the position of the focus position on the back focal plane, it is capable of being adjusted to change the incident angle with respect to the sample.