Single-Layer Radiation-Sensitive Hard Mask for Etch
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The existing methods for fabricating semiconductor integrated circuits using multi-layer resist etch masks face challenges in controlling critical dimension (CD) due to process variations and CD variations during optical lithography and dry etching processes.
Innovation Solution
A method involving a single-layer resist etch mask is developed, where a radiation-sensitive hard mask layer is formed on a substrate, exposed to actinic energy to alter solvent solubility, and then treated with water to create a masking pattern, allowing for precise control of feature dimensions during etching.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If multi-layer resist is used as etch mask, then the etch mask can be formed for dry etching process, but process variation and CD variation are introduced during optical lithography and dry etching processes
Solution Approach 1:
The patent extracts and eliminates the photoresist layer from the traditional multi-layer resist structure, retaining only the hard mask layer. This hard mask layer is directly patterned using radiation-sensitive materials and developed with water or aqueous solutions, removing the source of CD variation introduced by optical lithography of photoresist while maintaining the necessary etch mask functionality.
Solution Approach 2:
The patent changes the development parameter from organic solvent-based development (traditional photoresist) to water-based development. This parameter change enables direct patterning of the hard mask layer with reduced process variation and improved CD control, as water development provides more consistent results without the variations inherent in optical lithography processes.
2Ease of manufacture
If traditional optical lithography is used for pattern transfer, then the pattern can be transferred to photoresist, but CD variation is introduced during the process
Solution Approach 1:
The patent replaces the optical lithography system with a direct radiation-sensitive material patterning approach. Instead of using optical lenses and photoresist chemistry, the invention uses radiation-sensitive hard mask materials that can be directly patterned and developed with water, eliminating the optical system's inherent CD variation while maintaining pattern transfer capability.
3Reliability
If multi-layer resist structure is used, then adequate mask for etching can be provided, but process complexity increases
Solution Approach 1:
The patent extracts and removes the photoresist interlayer from the multi-layer resist structure, leaving only the essential hard mask layer. This simplification maintains adequate etch mask functionality while reducing process complexity by eliminating the additional patterning and development steps associated with multiple layers.
Solution Approach 2:
The patent merges the functions of the photoresist layer and hard mask layer into a single integrated hard mask layer made from radiation-sensitive material. This merging eliminates the need for separate photoresist application, optical lithography, and hard mask patterning steps, thereby reducing process complexity while maintaining etch mask adequacy.
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 reduces process and CD variations, enabling more accurate and consistent fabrication of semiconductor circuit features with improved control over critical dimensions.
Implementation Method 1
exposing the hard mask layer to actinic energy to change solvent solubility of exposed regions of the hard mask layer
Data Source
AI summary
A method of forming an etch mask includes: providing a substrate having thereon a material layer to be etched; forming a hard mask layer consisting of a radiation-sensitive, single-layer resist material on the material layer; exposing the hard mask layer to actinic energy to change solvent solubility of exposed regions of the hard mask layer; and subjecting the hard mask layer to water treatment to remove the exposed regions of the hard mask layer, thereby forming a masking pattern consisting of unexposed regions of the hard mask layer.