Area-Selective Etching Using Halogenated Hydrocarbon Priming
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Solution Overview
Problem
Conventional etching processes for semiconductor devices face challenges in precise control of etch selectivity and uniformity, particularly for thinner dielectric materials, and often damage underlying layers, with existing methods being aspect-ratio dependent and lacking specificity.
Innovation Solution
The method involves using a substrate with distinct first and second surfaces, where a halogenated hydrocarbon etch-priming reactant is deposited on the first surface, and reactive species generated from plasma are used to selectively etch the material, achieving a self-limiting process with controlled etch selectivity and minimal impact on the second surface.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If conventional RIE is used for etching dielectric layers, then etch rate is high, but etch selectivity control and uniformity are difficult for thinner materials
Solution Approach 1:
The etching process is segmented into two distinct steps: first depositing an etch-priming layer of halogenated hydrocarbon on the dielectric surface, then exposing to plasma for selective etching. This segmentation allows independent optimization of each step, achieving both high etch rate and precise selectivity control.
Solution Approach 2:
The etch-priming layer is deposited in advance before the actual etching process. This preliminary action modifies the surface chemistry of the dielectric, making it more reactive to plasma etching while protecting underlying layers, thus enabling better selectivity control.
2Ease of manufacture
If conventional etching processes are used, then etching can be performed, but underlying material layers are damaged
Solution Approach 1:
The halogenated hydrocarbon etch-priming layer acts as an intermediary between the plasma etching process and the dielectric layer. It selectively reacts with the dielectric surface to enable controlled etching while preventing direct plasma damage to underlying sensitive layers.
Solution Approach 2:
The process changes the chemical state of the dielectric surface by depositing the etch-priming layer, which alters the surface reactivity. This parameter change enables selective etching at controlled rates without the harsh conditions that would damage underlying layers.
3Adaptability or versatility
If fluorocarbon layers deposited by plasma-assisted CVD are used, then etching process adjustability is improved, but specificity is lost and process drift occurs
Solution Approach 1:
The etch-priming layer provides localized chemical modification only at the dielectric surface where needed. This local quality change enables selective etching of specific areas with high precision, maintaining etching specificity while allowing process adjustability through controlled deposition parameters.
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 and selective etching of materials, achieving an etch selectivity ratio of 1.5 or greater, with minimal etching of the second surface, thereby improving the scalability and versatility of semiconductor device manufacture.
Implementation Method 1
providing an etch-priming reactant into the reaction chamber in vapor phase. The etch-priming reactant is deposited on the first surface
Implementation Method 2
providing reactive species generated from plasma into the reaction chamber for selectively etching material from the first surface
Implementation Method 3
The etch-priming reactant comprises a halogenated hydrocarbon
Data Source
AI summary
The current disclosure relates to processes for selectively etching material from one surface of a semiconductor substrate over another surface of the semiconductor substrate. The disclosure further relates to assemblies for etching material from a surface of a semiconductor substrate. In the processes, a substrate comprising a first surface and a second surface is provided into a reaction chamber, an etch-priming reactant is provided into the reaction chamber in vapor phase; reactive species generated from plasma are provided into the reaction chamber for selectively etching material from the first surface. The etch-priming reactant is deposited on the first surface and the etch-priming reactant comprises a halogenated hydrocarbon. The halogenated hydrocarbon may comprise a head group and a tail group, and one or both of them may be halogenated.