Amorphous Carbon Pellicle for EUV Lithography
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Solution Overview
Problem
Current semiconductor fabrication methods using extreme ultraviolet lithography face challenges with the high absorptivity of EUV light by many substances, requiring a reflection type optical system, and existing pellicles lack sufficient EUV permeability, heat resistance, and durability.
Innovation Solution
A pellicle with an amorphous carbon layer having a mixed sp2 and sp3 carbon bond structure is integrated with a substrate to form a support, enhancing EUV permeability and heat resistance, and improving durability by eliminating the need for a peeling process, which reduces process defects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If a conventional pellicle is used in EUV lithography, then the pellicle can be attached to the reticle, but the EUV light transmission is insufficient due to high absorptivity
Solution Approach 1:
The pellicle material is changed from conventional materials to amorphous carbon with specific properties. The amorphous carbon layer has low absorptivity for EUV light, achieving 65% or higher transmission rate at 13.5nm wavelength, thus resolving the light transmission issue.
Solution Approach 2:
The pellicle is constructed as a composite structure with multiple layers including amorphous carbon layer, support layer, and adhesive layer. This composite design optimizes both light transmission and mechanical strength, overcoming the limitation of single-material pellicles.
2Reliability
If the pellicle is attached using conventional methods, then the attachment is achieved, but heat resistance and durability are insufficient
Solution Approach 1:
The adhesive layer uses a photoresist material with enhanced properties that provides both adhesion and heat resistance. The support layer material is selected to have high thermal stability, enabling the pellicle to withstand EUV lithography processing temperatures without degradation.
3Manufacturing precision
If the amorphous carbon layer is formed separately and then attached to the substrate, then the layer can be positioned, but process defects increase due to the peeling process
Solution Approach 1:
The amorphous carbon layer is formed integrally with the substrate in a single deposition process, eliminating the need for separate peeling and attachment steps. This integration reduces process complexity and eliminates defects that would otherwise be introduced by handling and peeling the carbon layer.
Solution Approach 2:
The amorphous carbon layer is formed directly on the substrate during the substrate preparation stage, before any subsequent processing steps. This preliminary formation ensures the layer is already in its final position and eliminates the need for later peeling and reattachment operations.
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 amorphous carbon pellicle with a mixed carbon bond structure effectively transmits and reflects EUV light, improving the semiconductor fabrication process by increasing EUV permeability and heat resistance, while reducing defects and contamination risks.
Implementation Method 1
The amorphous carbon layer having a structure in which a sp2 carbon bond structure and a sp3 carbon bond structure are mixed with each other... transmitting the EUV light through the pellicle
Implementation Method 2
reflecting the EUV light using the reticle
Data Source
AI summary
A method for fabricating a semiconductor device includes forming a pellicle including an amorphous carbon layer, attaching the pellicle onto a reticle, and forming a photoresist pattern by utilizing EUV light transmitted through the pellicle and reflected by the reticle. The forming the pellicle includes forming a first dielectric layer on a first side of the substrate, forming the amorphous carbon layer on the first dielectric layer, forming a second dielectric layer on a second side of the substrate opposite to the first side of the substrate, etching the second dielectric layer overlapping the first region of the substrate to form a mask pattern, and forming a support including the second region of the substrate and the remaining part of the first dielectric layer. The forming the support includes etching the first region of the substrate and the first dielectric layer on the first region.