Transparent Chuck Imaging Layout for Wafer Planarization
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Solution Overview
Problem
Current planarization techniques in semiconductor fabrication face challenges in effectively addressing substrate topography, leading to irregular height variations that hinder further layer addition and patterning accuracy, particularly in lithographic processes like ArF laser-based lithography, EUV lithography, and nanoimprint lithography.
Innovation Solution
An apparatus and method utilizing an array of image sensors and UV light sources, including UV LEDs, to acquire local images and cure a curable material on a substrate, minimizing light source and image sensor overlap, and integrating these components to achieve efficient planarization and curing, allowing for improved substrate flattening and feature precision.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If an array of image sensors and UV light sources are integrated in close proximity, then the curing efficiency and planarization precision are improved, but light interference between the light sources and image sensors increases
Solution Approach 1:
A beam splitter is introduced as an intermediary optical element between the UV light sources and image sensors. The beam splitter directs UV light toward the substrate for curing while simultaneously allowing visible light from the substrate to reach the image sensors for topography measurement, thereby resolving the light interference problem while maintaining close integration of components
Solution Approach 2:
Different regions of the optical system are optimized for different wavelengths: the UV light sources and their optical paths are optimized for UV curing, while the image sensor regions are optimized for visible light detection. This local optimization allows both functions to operate effectively in close proximity without mutual interference
2Device complexity
If the distance between light sources and image sensors is reduced, then the system compactness and integration are improved, but the image quality and measurement precision deteriorate due to light overlap
Solution Approach 1:
The beam splitter serves as a mediating optical component that enables close integration of UV light sources and visible light sensors without compromising image quality. It selectively directs different wavelengths to their respective destinations, maintaining measurement precision while achieving system compactness
Solution Approach 2:
The optical system is designed to operate in different wavelength dimensions simultaneously. UV light and visible light are separated and directed along different optical paths using the beam splitter, allowing close physical integration without spectral interference that would degrade image quality
3Manufacturing precision
If a transparent chuck is used to allow light transmission for curing, then the curing uniformity is improved, but the structural strength and support capability are reduced
Solution Approach 1:
The chuck is constructed from composite materials that combine transparency to UV light with sufficient structural strength. This allows the chuck to maintain its support capability while enabling uniform UV light transmission for consistent curing across the substrate surface
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
The solution enhances planarization by minimizing substrate height variations, improving depth of focus, critical dimension uniformity, and feature placement, thereby facilitating more precise semiconductor device fabrication and whole wafer processing.
Implementation Method 1
The array of light sources is configured to generate UV light to transmit through the chuck and the superstrate and the template. For example, the array of light sources may include an array of UV light emitting diodes (LEDs).
Implementation Method 2
A planarization technique sometimes referred to as inkjet-based adaptive planarization (IAP) involves dispensing a variable drop pattern of polymerizable material between the substrate and a superstrate... after which the material is polymerized on the substrate
Implementation Method 3
The array of image sensors and the array of the light sources are arranged to minimize an overlap between each individual image sensor and each individual light source. The image sensors may be configured to measure visible light.
Data Source
AI summary
An apparatus is provided. The apparatus has a chuck having a first side configured to retain a superstrate or a template and a second side, an array of image sensors disposed at the second side of the chuck and spaced from the chuck, and an array of light sources disposed between the transparent chuck and the array of image sensors.