Plasma Etch Sidewall Profile Control via Faceting and Passivation
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Solution Overview
Problem
The challenge in microelectronic development is creating specific structure profiles that are costly and difficult to control, particularly in feature scaling, where existing methods struggle to achieve precise sidewall profiles using sidewall faceting and passivation growth.
Innovation Solution
A method involving three plasma etch processes: the first generates a faceted sidewall, the second creates a passivation layer using oxygen, nitrogen, or combined plasmas, and the third induces differential etch rates on the faceted sidewall and passivation layer to achieve a target sidewall profile down to the underlying stop layer, utilizing a system with a process chamber, plasma generator, etchant gas delivery, controller, power source, and vacuum system.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional methods are used to create specific structure profiles, then manufacturing cost and process complexity increase, but manufacturing precision and control remain insufficient
Solution Approach 1:
The patent divides the structure profile creation into multiple discrete etch steps, each targeting specific portions of the sidewall. The first etch step creates an initial faceted profile, the second step adds a passivation layer, and subsequent steps selectively remove material to achieve the final profile. This segmentation allows precise control over different regions of the sidewall independently.
Solution Approach 2:
The patent applies preliminary actions by first creating a faceted sidewall profile and then depositing a passivation layer before the final etching step. This preliminary structuring enables better control during subsequent etching operations, as the passivation layer protects specific regions and guides the etch front to achieve the desired final profile with higher precision.
2Manufacturing precision
If multiple etch steps with passivation layers are used, then sidewall profile precision improves, but processing time increases
Solution Approach 1:
The patent maintains continuity by performing the etch-passivation-etch sequence in a continuous workflow without breaking the process chain. Each step flows directly into the next, with the passivation layer being deposited immediately after the first etch and removed in the subsequent etch step. This continuous approach minimizes idle time and maximizes equipment utilization while achieving precise sidewall profiles.
Solution Approach 2:
The patent uses partial action by applying the passivation layer only to specific regions of the sidewall that require protection, rather than uniformly coating the entire structure. The etch parameters are tuned to remove material only where needed, leaving protected regions intact. This selective approach achieves the desired profile precision without unnecessary processing steps.
3Productivity
If feature scaling continues, then device density increases, but structure creation cost and complexity increase
Solution Approach 1:
The patent employs self-service mechanisms where the etch process itself creates the faceted sidewall profile without requiring additional lithography or deposition steps. The anisotropic etching naturally forms the desired geometry based on crystallographic orientations, and the passivation layer selectively protects regions that need to be retained. This self-organizing behavior reduces process complexity while enabling feature scaling.
Solution Approach 2:
The patent utilizes parameter changes by varying etch chemistry, power, pressure, and gas flow rates between steps to achieve different etch rates and selectivity. These parameter adjustments enable the same etch equipment to create diverse structure profiles across different feature sizes, supporting device scaling without requiring new fabrication tools or excessively complex process sequences.
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 allows for precise control of sidewall profiles, achieving breakthroughs on near-horizontal surfaces and producing target sidewall profiles with improved control and accuracy, enhancing the complexity and cost-effectiveness of microelectronic structure creation.
Implementation Method 1
a first plasma etch process performed generating a faceted sidewall
Implementation Method 2
generating a faceted sidewall and a desired inflection point
Implementation Method 3
a second plasma etch process is performed using an oxygen, nitrogen, or combined oxygen and nitrogen plasma, generating a passivation layer
Implementation Method 4
generating a passivation layer
Implementation Method 5
a third plasma etch process using operating variables of an etch chemistry on the faceted sidewall and the passivation layer to induce differential etch rates
Implementation Method 6
achieve a breakthrough on near-horizontal surfaces of the structure
Data Source
AI summary
Provided is a method of creating structure profiles on a substrate using faceting and passivation layers. A first plasma etch process performed generating a faceted sidewall and a desired inflection point; a second plasma etch process is performed using an oxygen, nitrogen, or combined oxygen and nitrogen plasma, generating a passivation layer; and a third plasma etch process using operating variables of an etch chemistry on the faceted sidewall and the passivation layer to induce differential etch rates to achieve a breakthrough on near-horizontal surfaces of the structure, wherein the third plasma etch used is configured to produce a target sidewall profile on the substrate down to the underlying stop layer. Selected two or more plasma etch variables are controlled in the performance of the first plasma etch process, the second plasma etch process, and/or the third plasma etch process in order to achieve target sidewall profile objectives.