EUV Mask Phase-Shifting Material Defect Compensation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
EUV masks used in microelectronic device manufacturing often suffer from defects such as contaminations, pattern defects, and multilayer defects, which cause phase and amplitude variations in reflected radiation, leading to interference issues during exposure processes.
Innovation Solution
An EUV mask with a substrate and a reflective multilayer, where a phase-shifting material is deposited above the multilayer in specific portions to compensate for phase-shift differences caused by defects, using materials like zirconium, molybdenum, beryllium, carbon, or silicon dioxide, and a masking material corresponding to mask patterns, to adjust the phase-shift difference in a predetermined manner.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a reflective multilayer is used in EUV masks to reflect radiation, then the mask can function in EUV lithography processes, but defects within or beneath the multilayer cause phase-shift differences and interference patterns that deteriorate exposure quality
Solution Approach 1:
The patent applies local quality by depositing phase-shifting material only in specific first portions of the substrate where defects are located, rather than uniformly across the entire mask. This localized approach compensates for phase-shift differences caused by multilayer defects while preserving the optical properties of defect-free regions, thereby resolving the contradiction between maintaining mask functionality and eliminating harmful phase-shift effects.
Solution Approach 2:
The phase-shifting material acts as an intermediary layer between the substrate and the incoming radiation. By introducing this intermediate layer with specific optical properties, the patent compensates for the phase-shift differences caused by defects in the multilayer, thereby reducing interference patterns while maintaining the reflective function of the multilayer structure.
2Object-affected harmful factors
If phase-shifting material is deposited above the multilayer to compensate for defects, then phase differences are reduced, but the device structure becomes more complex
Solution Approach 1:
The phase-shifting material is deposited only in first portions of the substrate where defects are located, rather than across the entire mask surface. This localized deposition strategy reduces phase differences in affected areas while minimizing the overall structural complexity and material usage, thereby resolving the contradiction between defect compensation and device simplicity.
Solution Approach 2:
The mask structure is segmented into different regions: first portions with phase-shifting material for defect compensation, and second portions with masking material for pattern formation. This segmentation allows each region to perform its specific function independently, reducing overall complexity while achieving the desired phase compensation效果.
3Object-affected harmful factors
If the phase-shifting material thickness is increased to improve phase compensation, then phase-shift difference compensation improves, but absorption ability increases which may reduce radiation transmission
Solution Approach 1:
The patent optimizes the thickness parameter of the phase-shifting material to achieve the desired phase compensation效果. By carefully controlling the thickness within a specific range, the patent balances the phase-shifting ability with the absorption characteristics, ensuring effective defect compensation while minimizing radiation energy loss through the mask structure.
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 phase-shifting material effectively compensates for defects, reducing phase differences and ensuring consistent radiation patterns, thereby improving the accuracy and reliability of the EUV mask during exposure processes.
Implementation Method 1
a phase-shifting material above the multilayer in at least one first portion of the substrate... in which area a phase-shift difference of an exposure radiation is caused by a defect disposed one of beneath and within the multilayer
Implementation Method 2
The resulting phase difference in reference to the radiation reflected by portions without defects may cause variations of the intensity of the reflected radiation due to interferences
Implementation Method 3
EUV masks typically comprise a substrate with a reflective multilayer disposed on it... EUV masks used are mostly reflective masks because virtually all materials strongly absorb radiation in this wavelength range
Implementation Method 4
virtually all materials strongly absorb radiation in this wavelength range
Data Source
AI summary
An EUV mask comprises a substrate, a reflective multilayer on the substrate, a phase-shifting material disposed above the multilayer in at least one first portion of the substrate, and a masking material disposed above the multilayer in second portions of the substrate and corresponding to mask patterns of an EUV mask. There is also provided a method for repairing an EUV mask including a substrate, a reflective multilayer on the substrate and at least one defect beneath or within the multilayer. The method includes the steps of determining the position of a defect area of the substrate, in which a phase-shift difference of an exposure radiation is caused by the defect, and depositing a phase-shifting material above the multilayer in at least one first portion of the substrate, the first portion at least partially comprising the defect area.