Hard Mask Stress Compensation for Sub-Micron Pattern Fidelity
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Solution Overview
Problem
In photolithography processes for integrated circuits, internal stress in hardmask layers can cause pattern deformation, leading to loss of fidelity and resolution, especially as feature sizes approach the sub-micron range.
Innovation Solution
The process involves either thermal treatment or depositing a stress-compensating layer to adjust and reduce internal stress in the hardmask layer, ensuring pattern fidelity and resolution by counteracting the inherent stress, thereby preventing distortion during patterning.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If thermal treatment or stress-compensating layer is applied to reduce internal stress in hardmask layer, then pattern fidelity and resolution are maintained, but process complexity increases
Solution Approach 1:
The patent applies stress-compensating layers or performs thermal treatment on the hardmask layer before patterning to pre-adjust internal stress. This preliminary action prevents pattern deformation during subsequent processing, maintaining fidelity without requiring complex real-time corrections
Solution Approach 2:
The patent modifies physical parameters of the hardmask layer by introducing stress-compensating layers with specific stress characteristics or by applying thermal treatment to change the stress state. These parameter changes directly address the internal stress issue while preserving pattern integrity
2Manufacturing precision
If internal stress in hardmask layer is reduced through stress-compensating processes, then pattern resolution is maintained at sub-micron scales, but manufacturing time and energy consumption increase
Solution Approach 1:
Stress compensation is performed as a preliminary step before patterning, allowing standard patterning processes to be used without requiring slower, more time-consuming alternative methods. The pre-adjusted stress state enables rapid subsequent processing
Solution Approach 2:
The patent replaces mechanical stress management approaches with thermal treatment or material-based stress compensation. These substitutions enable stress control without requiring complex mechanical interventions that would consume additional time
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 maintains pattern fidelity and resolution by reducing internal stress in the hardmask layer, allowing for precise patterning and etching of underlying layers, even at deep sub-micron scales.
Implementation Method 1
The process involves either thermal treatment or depositing a stress-compensating layer to adjust and reduce internal stress in the hardmask layer
Implementation Method 2
depositing a stress-compensating layer to adjust and reduce internal stress in the hardmask layer
Data Source
AI summary
As deposited, hard mask thin films have internal stress components which are an artifact of the material, thickness, deposition process of the mask layer as well as of the underlying materials and topography. This internal stress can cause distortion and twisting of the mask layer when it is patterned, especially when sub-micron critical dimensions are being patterned. A stress-compensating process is employed to reduce the impact of this internal stress. Heat treatment can be employed to relax the stress, as an example. In another example, a second mask layer with an opposite internal stress component is employed to offset the internal stress component in the hard mask layer.