Semiconductor Patterning With Differential Passivation for Straight Etching
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Solution Overview
Problem
The semiconductor industry faces challenges in patterning semiconductor devices due to low etching selectivity between material layers, leading to issues like undesired etching profiles and iso/dense loading, which complicates the manufacturing process and affects the precision of feature sizes in integrated circuits.
Innovation Solution
A method involving the use of a passivation layer formed by molecular layer deposition (MLD) is applied over material layers with different etching selectivities, allowing for controlled etching processes that protect the second material layer from damage while patterning the first material layer, resulting in straight profiles and reduced bowing due to polymer clogging.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional etching processes are used on material layers with low etching selectivity, then the etching process can proceed, but undesired etching profiles and damage to the second material layer occur
Solution Approach 1:
A mandrel layer is introduced as an intermediary between the first and second material layers. This mandrel layer has high etching selectivity difference relative to both the first and second material layers, serving as a protective mediator that prevents direct harmful interaction between the etching process and the second material layer while enabling precise patterning of the first material layer
Solution Approach 2:
The structure is segmented into three distinct layers (first material layer, mandrel layer, second material layer) with the mandrel layer acting as a separate protective segment. This segmentation allows the etching process to be performed on the first material layer without directly affecting the second material layer, as the mandrel layer segment absorbs the etching action
2Manufacturing precision
If etching is performed on the first material layer, then the first material layer can be patterned, but polymer clogging causes bowing and curved profiles
Solution Approach 1:
The mandrel layer serves as an intermediary that prevents polymer clogging from reaching and affecting the interface between the first material layer and the underlying structure. By positioning the mandrel layer between the first material layer and the second material layer, it acts as a barrier that maintains straight etching profiles without the bowing caused by polymer accumulation
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 enables precise patterning of semiconductor devices by ensuring the second material layer is protected during etching, maintaining the integrity of the second material layer and achieving straight etching profiles, thereby improving manufacturing efficiency and reducing defects.
Implementation Method 1
A passivation layer is formed over the first material layer and the second material layer. The passivation layer may be formed by a process such as, but not limited to, molecular layer deposition (MLD).
Data Source
AI summary
A patterning method includes at least the following steps. A first material layer is provided. A second material layer is provided over the first material layer. The second material layer partially exposes the first material layer. A passivation layer is formed over the first material layer and the second material layer. A growth rate of the passivation layer on the second material layer is greater than a growth rate of the passivation layer on the first material layer. A first etching process is performed to remove a portion of the passivation layer and a portion of the first material layer.