Optical Enhancement Layer for Detecting Tungsten CMP Nanoparticles
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Solution Overview
Problem
Conventional optical scan methodologies fail to detect nano-sized tungsten particles during semiconductor manufacturing due to their deep subwavelength size, leading to yield-limiting defects and delayed corrective process changes.
Innovation Solution
The implementation of an optical detection method involving an optical enhancement layer, such as TiN or titanium oxide, to enhance the visibility of nano-sized tungsten particles by scattering light and improving the signal-to-noise ratio during inspection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional optical scan methodologies are used, then the inspection process is simple and fast, but nano-sized tungsten particles cannot be detected due to their deep subwavelength size
Solution Approach 1:
An optical enhancement layer is introduced as an intermediary between the inspection system and the tungsten particles. This layer has tailored optical properties that amplify the scattering signal from subwavelength particles, enabling detection without requiring a larger inspection system aperture.
Solution Approach 2:
The optical properties of the enhancement layer are specifically engineered to change the scattering characteristics. By adjusting the layer's refractive index and thickness, the system transforms undetectable subwavelength particles into detectable optical signals within the existing wavelength range.
2Measurement precision
If conventional optical inspection is used, then the process is fast, but detection precision for subwavelength particles is insufficient
Solution Approach 1:
The optical enhancement layer is deposited on the wafer surface before the inspection process. This preliminary action prepares the surface to actively enhance the optical signal from particles during inspection, eliminating the need for slower post-inspection analysis or repeated scanning.
3Measurement precision
If larger inspection system aperture is used to detect smaller particles, then detection capability improves, but equipment complexity and cost increase
Solution Approach 1:
The optical enhancement layer serves as a mediator that amplifies the optical interaction between inspection light and subwavelength particles. This allows standard-sized inspection apertures to achieve the detection sensitivity that would otherwise require much larger, more complex systems.
Solution Approach 2:
The enhancement layer is designed to modify the optical scattering characteristics, effectively changing how particles interact with inspection light. This transformation enables detection of subwavelength particles using conventional optical wavelengths and aperture sizes.
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 effective detection of nano-sized tungsten particles, allowing for timely process adjustments to reduce defects and improve manufacturing yield.
Implementation Method 1
The implementation of an optical detection method involving an optical enhancement layer, such as TiN or titanium oxide, to enhance the visibility of nano-sized tungsten particles by scattering light and improving the signal-to-noise ratio during inspection.
Data Source
AI summary
Chemical mechanical polish processes on surfaces of semiconductor devices comprising tungsten layers can create nano-sized particles of tungsten. These particles can create manufacturing yield reductions. These particles can also be difficult to detect optically. Etched surfaces coated with a layer of material that can provide optical detection enhancement provide an ability to optically detect nano-sized particles.