Conductive Line Spoon-Shaped Receptacle Over-etching
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Solution Overview
Problem
In integrated circuitry, forming electrically conductive lines with recessed access devices poses a risk of over-etching into other device components due to the need to reach deeper into the substrate, requiring multiple mask and etching steps to avoid damage.
Innovation Solution
The method involves forming a longitudinally elongated conductive line within a trench with a spoon-like shape at one end, where the first conductive material forms a receptacle and the second conductive material overfills and projects outward, allowing for selective etching to recess the first material and reduce the volume of the receptacle before forming insulative material and contact openings.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If contact openings are etched deeper to reach the recessed line, then electrical connection to the recessed line is achieved, but over-etching into other device components occurs
Solution Approach 1:
The patent applies preliminary action by forming a protective cap structure over the recessed conductive line before etching contact openings. This cap structure is formed in advance to prevent over-etching during subsequent processing steps, allowing the etch to reach the recessed line without damaging surrounding components.
Solution Approach 2:
The patent uses an intermediary protective structure (cap formed from conductive material or other materials) that mediates between the etching process and the recessed conductive line. This intermediary layer allows the etch to proceed to the required depth while protecting adjacent device components from over-etching damage.
2Object-affected harmful factors
If multiple mask and etching steps are conducted to protect elevation devices, then over-etching is prevented, but device complexity and manufacturing time increase
Solution Approach 1:
The patent merges multiple protective functions into a single cap structure that can be formed in one deposition step. This consolidated approach replaces what would otherwise require multiple separate mask and etching steps, reducing processing complexity while maintaining protection against over-etching.
Solution Approach 2:
The cap structure serves multiple functions simultaneously: it protects the recessed conductive line during etching, defines the contact opening location, and can serve as part of the final conductive structure. This multi-functionality reduces the need for separate processing steps.
3Productivity
If the conductive line is recessed deeper in the substrate, then interconnect density is improved, but the risk of over-etching into surrounding components increases
Solution Approach 1:
The patent forms a protective cap structure in advance before etching contact openings to deeper levels. This preliminary protective measure enables the conductive line to be recessed deeper for improved interconnect density while preventing over-etching into surrounding components during the deeper etching process.
Data Source
AI summary
A method of forming an electrically conductive buried line and an electrical contact thereto includes forming of a longitudinally elongated conductive line within a trench in substrate material. A longitudinal end part thereof within the trench is of spoon-like shape having a receptacle. The receptacle is filled with conductive material. Insulative material is formed over the conductive material that is within the receptacle. A contact opening is formed over the conductive material that is within the receptacle. Conductor material is formed in the contact opening in electrical connection with the second conductive material that is within the receptacle. Other method and device implementations are disclosed.