Organic Hard Mask Etching for Semiconductor Patterning
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Solution Overview
Problem
Conventional hard mask layers used in semiconductor manufacturing for etching deep, high aspect ratio features suffer from integrity issues due to reaction with free radicals, leading to inaccurate pattern formation and increased processing time, which affects the accuracy and efficiency of semiconductor chip manufacturing.
Innovation Solution
A method involving a first hard mask layer with an organic mask layer, comprising a dopant, is deposited on a feature layer over a substrate, where an opening is formed using a plasma with a halogen element at a temperature greater than room temperature, and a second hard mask layer is deposited to maintain mask integrity and control pattern features.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional hard mask layers are used for etching deep high aspect ratio features, then mask integrity is compromised due to reaction with free radicals, but using thicker mask stacks improves integrity while reducing transparency and increasing processing time
Solution Approach 1:
The patent applies parameter changes by etching the organic mask layer at an elevated temperature (greater than room temperature) using a halogen-containing plasma. This temperature parameter change modifies the etching chemistry to produce volatile by-products that can be easily removed, thereby maintaining mask integrity without requiring excessively thick mask stacks or prolonged processing times. The halogen element parameter also changes the reaction pathway to reduce mask erosion.
2Reliability
If thicker hard mask stacks are used to maintain mask integrity, then mask transparency is reduced making alignment marks invisible, but thinner masks improve transparency while compromising integrity
Solution Approach 1:
The patent uses parameter changes by etching at elevated temperature with halogen-containing plasma, which produces volatile by-products that can be removed without requiring excessive mask thickness. This allows the use of thinner organic mask layers that maintain both structural integrity during etching and sufficient transparency for alignment mark visibility, resolving the contradiction between these two requirements.
3Manufacturing precision
If conventional photoresists are used for patterning, then shallow features can be patterned, but deep high aspect ratio features cannot be etched with sufficient precision, requiring harder masks that are more difficult to process
Solution Approach 1:
The patent applies parameter changes by using elevated temperature etching with halogen-containing plasma specifically for organic mask layers. This creates a processing regime where organic masks (which are easier to deposit and more transparent than conventional hard masks) can achieve the necessary integrity for deep high aspect ratio feature etching. The temperature and chemistry parameters enable organic masks to perform functions traditionally requiring harder, more difficult-to-process materials.
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 enhances the mechanical strength and transparency of the hard mask, allowing for improved pattern transfer parameters, increased etch selectivity, and reduced material usage, resulting in more precise and efficient semiconductor feature patterning.
Implementation Method 1
plasma etching is a form of plasma processing used to fabricate integrated circuits. It typically involves a high-speed stream of glow discharge (plasma) of an appropriate gas mixture being shot at a wafer. The plasma can contain ions, neutral atoms and radicals.
Implementation Method 2
Typically, during the etching process free radicals react with the mask material and erode the mask.
Implementation Method 3
The elevated temperature is adjusted to control the volatility of the by-products
Data Source
AI summary
A hard mask layer is deposited on a feature layer over a substrate. The hard mask layer comprises an organic mask layer. An opening in the organic mask layer is formed using a first gas comprising a halogen element at a first temperature greater than a room temperature to expose a portion of the feature layer. In one embodiment, a gas comprising a halogen element is supplied to a chamber. An organic mask layer on an insulating layer over a substrate is etched using the halogen element at a first temperature to form an opening to expose a portion of the insulating layer.