Mandrel Film Stress Modulation for Low-Roughness Patterning
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Solution Overview
Problem
Conventional lithography-based patterning processes face challenges in miniaturization due to high line edge roughness (LER) and line width roughness (LWR), especially with advanced mandrel films that cause wafer bowing and misalignment, limiting the effective resolution of semiconductor features as dimensions shrink.
Innovation Solution
Implementing a low-energy implant process (<10 kV) on mandrel film layers, followed by forming a mask film layer and patterning to create vertical features, using low stress films to reduce LER and LWR, and employing a plasma doping system for precise ion implantation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If high density mandrel film is used to reduce LWR, then line width roughness is improved, but wafer bowing and misalignment occur due to high stress
Solution Approach 1:
The patent applies low-energy ion implantation (less than 10 kV) to modify the stress parameters of the mandrel film. By controlling the implantation energy and dose, the film stress is reduced from high to low levels, eliminating wafer bowing and misalignment while preserving the high density required for low LWR. This parameter modification allows the film to maintain beneficial properties while eliminating harmful effects.
2Ease of manufacture
If conventional lithography-based patterning is used, then manufacturing process is simple, but line edge roughness and line width roughness increase at sub-micron dimensions
Solution Approach 1:
The patent performs low-energy ion implantation on the mandrel film before the patterning process. This preliminary action modifies the film's mechanical properties (reducing stress) and prepares it for subsequent patterning operations. By pre-conditioning the film, the process achieves better LER and LWR control during spacer formation and pattern transfer, while maintaining overall process simplicity.
3Productivity
If feature dimensions are reduced to increase circuit density, then circuit density is improved, but LER and LWR become more significant limiting resolution
Solution Approach 1:
The patent uses low-energy ion implantation to modify the mandrel film parameters (stress, density) to optimize performance at reduced feature dimensions. By adjusting the implantation energy and dose parameters, the film maintains structural integrity and low roughness even when scaled to sub-micron dimensions, enabling higher circuit density without sacrificing precision.
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
Achieves improved LER and LWR performance, reducing line wiggle, LER, and space width roughness, enabling better etch selectivity and thinner films for advanced semiconductor nodes.
Implementation Method 1
implanting an upper layer of the stack of mandrel film layers, wherein the implant is performed at an implant energy less than 10 kV
Data Source
AI summary
Provided herein are devices and techniques for using a low-energy implant for hard mask stress modulation. In one approach, a method may include providing a stack of mandrel film layers, implanting an upper layer of the stack of mandrel film layers, and forming a mask film layer over the upper layer. The method may further include forming a patterning layer over the mask film layer, partially removing the patterning layer and the mask film layer, and patterning the stack of mandrel film layers to form a set of vertical features.