Polish Pad Optical Transmissivity Control
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Solution Overview
Problem
Polishing pads used in semiconductor and optical product manufacturing often have inconsistencies in micro structure, leading to deviations in polish performance and are not suitable for optical endpoint detection due to light scattering and absorption, which reduces signal intensity below usable levels for endpoint detection.
Innovation Solution
The method involves controlling the optical transmissivity of polish pad materials by adjusting chemical ingredients, such as the ratio of hard to soft segments, and processing parameters like temperature and pressure during casting and curing, to create a homogeneous polymer pad with a window for enhanced light transmission, using centrifugal casting and machining techniques to achieve a polish pad with controlled optical properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If conventional polishing pad materials are used, then polishing performance is achieved, but optical transmissivity is poor due to light scattering and absorption
Solution Approach 1:
The polishing pad is designed with a window region that has different optical properties than the surrounding pad material. This window region is specifically engineered to be optically transparent or translucent, allowing light to pass through for endpoint detection, while the rest of the pad maintains its polishing functionality. This local differentiation resolves the contradiction by providing both polishing performance and optical transmissivity in different regions of the same component.
Solution Approach 2:
The polishing pad incorporates a composite structure combining pad material with a window material that has superior optical properties. The window material is selected to be optically transparent or translucent in the visible spectrum, while the pad material provides mechanical support and polishing function. This composite approach allows the system to achieve both good polishing performance and high optical transmissivity simultaneously.
2Measurement precision
If homogeneous polymer pad is created with controlled transmissivity, then endpoint detection is enabled, but manufacturing complexity increases
Solution Approach 1:
The window region is formed during the casting process itself rather than as a separate post-processing step. By incorporating the window formation into the initial casting operation, the manufacturing process integrates multiple functions into a single step, reducing overall complexity despite the enhanced measurement precision capability.
Solution Approach 2:
The optical transmissivity of the polishing pad is controlled by adjusting parameters during the casting and curing processes, such as temperature, pressure, and chemical composition. By optimizing these parameters, the pad achieves the desired optical properties for endpoint detection without requiring complex additional manufacturing steps, thus balancing measurement precision with manufacturing simplicity.
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
This approach results in a polish pad with controlled optical transmissivity, enabling effective endpoint detection by optimizing light transmission through the pad, thereby improving the accuracy and reliability of the polishing process.
Implementation Method 1
arranging a first polymer precursor for a sub-pad in a mold in a centrifugal caster, rotating the centrifugal caster to form the sub-pad
Implementation Method 2
optical transmissivity of the polish pad material... enabling effective endpoint detection by optimizing light transmission through the pad
Data Source
AI summary
A method and systems for controlling optical transmissivity of a polish pad material are provided. The method and systems may include adjusting control parameters to determine the optical transmissivity of a polish pad material. The control parameters may also include pre-processing controls, casting controls, and/or curing controls. Methods and systems also provided for assembling a polish pad that controls the optical transmissivity of the polish pad. Additionally, a polish pad with a controlled optical transmissivity is provided.