Profile Control Liner for Via Corner Protection in Dual Damascene
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Solution Overview
Problem
Existing dual damascene interconnect structures suffer from uncontrolled via chamfering, leading to increased risk of V1 to M1 shorting, poor electrical yield, and low reliability due to rounding of dielectric material corners during trench etching.
Innovation Solution
A profile control liner is formed within each via opening before creating the line opening, preventing rounding of dielectric material corners by remaining on exposed surfaces during the line opening formation, and a diffusion barrier is applied to both the via and line openings with conductive material filling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If trench etching is performed to form line openings in dual damascene interconnect structures, then signal transmission paths are created, but rounding of dielectric material corners (chamfering) occurs at via openings
Solution Approach 1:
A profile control liner is introduced as an intermediary material deposited within via openings before trench etching. This liner acts as a protective mediator that prevents the etching process from rounding the dielectric corners at via openings, while still allowing the etch to proceed and create the necessary line openings for signal transmission.
Solution Approach 2:
The profile control liner is deposited in advance of the trench etching process, performing a preliminary protective action. By pre-coating the via sidewalls and corners with this liner material, the structure is prepared to resist chamfering during the subsequent etching operation, ensuring via profile integrity is maintained before the line openings are created.
2Manufacturing precision
If profile control liner is deposited within via openings, then via profile control is improved, but process complexity increases
Solution Approach 1:
The profile control liner serves multiple functions simultaneously: it protects via corners from chamfering during etching, provides a defined interface for subsequent barrier liner deposition, and maintains via opening geometry. By combining these functions into a single material layer, the process complexity is minimized while achieving comprehensive via profile control.
Data Source
AI summary
The profile of a via can be controlled by forming a profile control liner within each via opening that is formed into a dielectric material prior to forming a line opening within the dielectric material. The presence of the profile control liner within each via opening during the formation of the line opening prevents rounding of the corners of a dielectric material portion that is present beneath the line opening and adjacent the via opening.