Radiation Detector Doping Profile for Lithography
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Solution Overview
Problem
Conventional transmission image sensors (TIS) used in lithographic apparatuses have a limited lifetime due to radiation-sensitive surface deterioration at wavelengths between 10-200 nm, which hampers the accuracy and yield of device manufacturing as the industry moves towards smaller pattern imaging and higher component densities.
Innovation Solution
A radiation detector with a silicon substrate and a dopant layer comprising a first layer of dopant material and a diffusion layer, connected by electrodes, forming a radiation-sensitive surface that maintains sensitivity and durability across the 10-200 nm wavelength range, enhancing the detector's lifetime and accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional radiation detector is used at substrate level, then it can detect radiation with wavelengths between 10-200 nm, but the radiation-sensitive surface deteriorates within a limited time frame, resulting in limited lifetime
Solution Approach 1:
The patent modifies the doping parameters of the silicon substrate, specifically creating a tailored doping profile with varying dopant concentrations at different depths. This includes a first dopant concentration in a first depth range and a second dopant concentration in a second depth range, which optimizes the detector's sensitivity and durability across the 10-200 nm wavelength range, thereby extending its operational lifetime
Solution Approach 2:
The radiation detector employs a composite structure combining silicon substrate with specific doping profiles and multiple dopant layers. This composite approach creates a radiation-sensitive surface with enhanced properties that resist deterioration from high-energy radiation while maintaining detection sensitivity, thus improving reliability and extending lifetime
2Manufacturing precision
If the wavelength is reduced to image smaller patterns for higher component densities, then imaging resolution improves, but the radiation-sensitive surface deteriorates faster, reducing overlay accuracy
Solution Approach 1:
The patent optimizes the doping profile parameters including dopant concentration gradients and depth distribution to enhance the radiation-sensitive surface's resistance to radiation damage. This allows the detector to maintain overlay measurement accuracy even when detecting shorter wavelengths used for imaging smaller patterns with higher component densities
3Reliability
If a radiation detector with extended lifetime is implemented, then overlay error reduction is achieved, but device complexity increases due to additional dopant layers and processing steps
Solution Approach 1:
The patent applies different dopant concentrations at different depths within the silicon substrate rather than uniform doping. This localized variation in doping quality creates optimal detection regions while managing complexity through targeted modifications rather than comprehensive structural changes
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 improved radiation detector provides extended lifetime and enhanced sensitivity, enabling more robust imaging performance and reduced overlay errors in lithographic processes, supporting the creation of devices with higher component densities and improved accuracy.
Implementation Method 1
The dopant layer comprises a first layer of dopant material and a second layer. The second layer is a diffusion layer which is in contact with the surface area at the first surface side of the silicon substrate
Implementation Method 2
The radiation detector has a radiation sensitive surface. The radiation-sensitive surface is sensitive for radiation with a wavelength between 10-200 nm
Data Source
AI summary
The invention relates to a radiation detector, a method of manufacturing a radiation detector and a lithographic apparatus comprising a radiation detector. The radiation detector has a radiation-sensitive surface. The radiation-sensitive surface is sensitive for radiation with a wavelength between 10-200 nm. The radiation detector has a silicon substrate, a dopant layer, a first electrode and a second electrode. The silicon substrate is provided in a surface area at a first surface side with doping profile of a certain conduction type. The dopant layer is provided on the first surface side of the silicon substrate. The dopant layer has a first layer of dopant material and a second layer. The second layer is a diffusion layer which is in contact with the surface area at the first surface side of the silicon substrate. The first electrode is connected to dopant layer. The second electrode is connected to the Silicon substrate.