Directional Mask Protection for High-Aspect-Ratio Dielectric Etching
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional etching methods struggle to uniformly etch high aspect ratio features in dielectric materials, leading to mask erosion and non-uniform profiles, limiting the achievable aspect ratio and compromising structural integrity.
Innovation Solution
A method involving a selective vertically-oriented directional deposition of an upper mask protector layer during etching, which forms on the mask layer without eroding it, ensuring infinite etch selectivity and preventing bowing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional etching methods are used to etch high aspect ratio features, then the etching process can proceed, but mask erosion occurs and etch selectivity is limited
Solution Approach 1:
A protective layer is deposited on the mask to act as an intermediary between the etching plasma and the mask material. This protective layer absorbs the harmful etching effects, preventing direct erosion of the mask while allowing the etching process to proceed uniformly on the dielectric material beneath.
Solution Approach 2:
The protective layer is deposited on the mask before the etching process begins. This preliminary action prepares the mask by providing a protective barrier in advance, preventing erosion during the subsequent etching operation and enabling infinite etch selectivity.
2Productivity
If conventional etching methods are used, then etching can occur, but non-uniform profiles and bowing are produced
Solution Approach 1:
The protective layer serves as a mediator that enables uniform etching by preventing plasma from directly interacting with the mask sidewalls. This intermediary layer ensures that etching proceeds vertically and uniformly, eliminating bowing and producing straight-walled high aspect ratio features.
3Ease of manufacture
If mask thickness is reduced to enable thinner masks, then processing time and costs are reduced, but mask erosion and loss of structural integrity occur
Solution Approach 1:
The protective layer acts as an intermediary that compensates for reduced mask thickness. By providing an additional protective barrier, it allows the use of thinner masks without compromising structural integrity, as the protective layer absorbs the erosive effects that would otherwise damage the thin mask.
Solution Approach 2:
The protective layer provides beforehand cushioning for the mask, particularly important when using thinner masks. This pre-deposited layer cushions the mask against plasma erosion during etching, preventing damage that would otherwise occur with reduced mask thickness.
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
Enables the formation of deeper, higher aspect ratio features with uniform profiles by protecting the mask from erosion, allowing for thinner masks and reducing processing time and costs.
Implementation Method 1
generating a plasma in the reaction chamber; and exposing the substrate to the plasma in the reaction chamber to simultaneously (i) etch the features in the dielectric material, and (ii) deposit an upper mask protector layer on the mask
Implementation Method 2
deposit an upper mask protector layer on the mask, where the upper mask protector layer forms on top of the mask in a selective vertically-oriented directional deposition
Implementation Method 3
the upper mask protector layer protects the mask from erosion during etching, such that an etch selectivity with respect to the dielectric material, as compared to the mask, is infinite
Data Source
AI summary
Provided herein are methods and apparatus for processing a substrate by exposing the substrate to plasma to simultaneously (i) etch features in an underlying material (e.g., which includes one or more dielectric materials), and (ii) deposit a upper mask protector layer on a mask positioned over the dielectric material, where the upper mask protector layer forms on top of the mask in a selective vertically-oriented directional deposition. Such methods and apparatus may be used to achieve infinite etch selectivity, even when etching high aspect ratio features.