Amorphous Carbon Hard Mask Layers for Wafer Stress and Etch Selectivity
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Solution Overview
Problem
As semiconductor devices miniaturize, achieving high film quality in hard masks while reducing wafer stress becomes challenging due to increased process temperatures, leading to issues like wafer chucking errors and contamination.
Innovation Solution
A multi-layer amorphous carbon hard mask is developed, with each layer having a distinct extinction coefficient ranging from 0.4 to 0.7, formed through varying deposition pressures to reduce wafer stress and improve etch selectivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If process temperature is increased to improve film quality of the hard mask, then film quality is improved, but wafer stress increases causing chucking errors and contamination
Solution Approach 1:
The hard mask is divided into multiple layers (first amorphous carbon layer and second amorphous carbon layer) with different extinction coefficients. This segmentation allows each layer to contribute differently to stress management while collectively providing high film quality, resolving the contradiction between improving film quality and reducing wafer stress.
Solution Approach 2:
The patent changes the extinction coefficient parameter between layers, with the first layer having an extinction coefficient of 0.2-0.4 and the second layer having 0.4-0.6. This parameter variation enables optimization of both film quality and stress characteristics without requiring increased process temperature.
2Ease of manufacture
If single-layer amorphous carbon hard mask is used, then process is simple, but etch selectivity is insufficient
Solution Approach 1:
The hard mask is segmented into two amorphous carbon layers with distinct extinction coefficients (first layer: 0.2-0.4, second layer: 0.4-0.6). This segmentation provides different etch resistances in each layer, improving overall etch selectivity while maintaining a relatively simple two-layer structure that is easier to manufacture than complex multi-material stacks.
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 multi-layer hard mask effectively reduces wafer stress and enhances etch selectivity compared to single-layer masks, minimizing defects and improving film quality during semiconductor manufacturing processes.
Implementation Method 1
The first layer may have a first extinction coefficient. The second layer may have a second extinction coefficient. The second extinction coefficient may be different from the first extinction coefficient.
Data Source
AI summary
A hard mask may include a first layer and a second layer on the first layer. Each of the first layer and the second layer may include an amorphous carbon layer. The first layer may have a first extinction coefficient. The second layer may have a second extinction coefficient and the second extinction coefficient may be different from the first extinction coefficient. The first extinction coefficient and the second extinction coefficient each may be in a range of 0.4 to 0.7.