Bottom-Up Filled Conductive Features for Low-Resistance Contacts
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Solution Overview
Problem
The challenge in semiconductor manufacturing is to enhance adhesion and reduce contact resistance in conductive features, particularly in advanced ICs with smaller geometries, where traditional methods struggle to maintain effective electrical performance.
Innovation Solution
A bottom-up deposition process is employed to form conductive features with convex structures that mate with concave surfaces of underlying features, increasing the contact surface area and improving adhesion, using techniques like thermal CVD with controlled nucleation sites to ensure seamless integration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional filling methods are used to form conductive features, then the manufacturing process is simpler, but contact resistance increases and adhesion deteriorates
Solution Approach 1:
The method performs preliminary actions by forming a recess in the first conductive feature before depositing the second conductive feature. This recess preparation ensures proper adhesion and reduces contact resistance by creating a mechanical interlock and increasing the contact surface area between the two conductive features.
Solution Approach 2:
The invention applies local quality by creating a convex structure of the second conductive feature that specifically mates with the concave recess of the first conductive feature. This localized structural modification enhances adhesion and electrical contact at the interface without affecting the entire structure uniformly.
2Reliability
If conductive features are formed with larger contact surface area, then adhesion improves and contact resistance reduces, but the manufacturing precision requirements increase
Solution Approach 1:
The invention utilizes curvature by forming a convex structure on the second conductive feature that complements the concave recess of the first conductive feature. This curved interface design increases the contact surface area and improves adhesion while the controlled geometry maintains manufacturability through standard deposition processes.
3Reliability
If bottom-up deposition process is used to form convex structures, then voids are prevented and adhesion is enhanced, but the process time and complexity increase
Solution Approach 1:
The method performs preliminary action by preparing the recess structure before deposition, which guides the bottom-up filling process. This pre-prepared geometry ensures that the conductive material fills from the bottom upward without forming voids, and the process is optimized to reduce deposition time while maintaining defect prevention.
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 enhances electrical performance by reducing contact resistance and preventing defects such as voids, while promoting stable adhesion and interface management in conductive features.
Implementation Method 1
A bottom-up deposition process is employed to form conductive features with convex structures that mate with concave surfaces of underlying features
Implementation Method 2
using techniques like thermal CVD with controlled nucleation sites to ensure seamless integration
Implementation Method 3
enhances adhesion and reduce contact resistance in conductive features
Data Source
AI summary
The present disclosure provides example embodiments relating to conductive features, such as metal contacts, vias, lines, etc., and methods for forming those conductive features. In some embodiments, a structure includes a first dielectric layer over a substrate, a first conductive feature through the first dielectric layer, the first conductive feature comprising a first metal, a second dielectric layer over the first dielectric layer, and a second conductive feature through the second dielectric layer having a lower convex surface extending into the first conductive feature, wherein the lower convex surface of the second conductive feature has a tip end extending laterally under a bottom boundary of the second dielectric layer.