Concave Contact Plug Structure to Prevent Interconnect Gaps
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Challenges arise during the scaling-down process of semiconductor devices, impacting electrical characteristics, quality, and yield, particularly in achieving satisfactory electrical connections between contact plugs and interconnection layers due to deep recesses in the contact plugs.
Innovation Solution
A semiconductor structure design with a concave upper surface for contact plugs, where the conductive material layer thickness over the insulation structure is sufficient to withstand planarization, minimizing recess extent and preventing voids, ensuring a stable electrical connection with an interconnection layer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the contact plug is formed with a deep recess to accommodate planarization, then the planarization operation can be performed, but voids or gaps form between the contact plug and interconnection layer
Solution Approach 1:
The patent applies preliminary action by forming a mandrel structure before the contact plug that defines the desired final shape. The mandrel is removed after contact plug formation, leaving the contact plug with a protruding upper surface that prevents void formation. This preliminary structuring enables both planarization and reliable electrical connection.
Solution Approach 2:
The patent changes the geometric parameters of the contact plug by controlling the thickness of the conductive material layer to be greater than half the trench width. This parameter adjustment ensures that after planarization, the contact plug maintains a protruding upper surface rather than a deep recess, solving the void formation problem while preserving planarization quality.
2Reliability
If the conductive material layer thickness is reduced to minimize contact plug recess, then electrical connection is improved, but the planarization operation becomes unstable
Solution Approach 1:
The patent optimizes the thickness parameter of the conductive material layer, specifying it should be greater than half the trench width. This parameter setting balances two requirements: it provides sufficient material to sustain planarization stability while limiting the recess depth to prevent void formation, achieving both manufacturing precision and electrical connection reliability.
Solution Approach 2:
The patent incorporates feedback by using the trench width as a reference dimension to determine the appropriate conductive material layer thickness. The thickness criterion (greater than half the trench width) provides a feedback-based design rule that ensures planarization stability while preventing excessive recess, thereby maintaining both process control and electrical performance.
3Productivity
If the semiconductor device dimensions are scaled down to increase computing ability, then productivity is improved, but manufacturing precision and yield deteriorate
Solution Approach 1:
The patent addresses scaling challenges by establishing specific parameter relationships that remain valid across different device sizes. The criterion that conductive material layer thickness exceeds half the trench width provides a scalable design rule that maintains manufacturing precision and electrical connection quality even as device dimensions are reduced to increase computing ability.
Solution Approach 2:
The patent applies local quality by creating a protruding upper surface configuration specifically at the contact plug region, while other structures maintain their conventional geometry. This localized geometric modification targets the specific problem area (contact plug-to-interconnection interface) without requiring changes to the entire device structure, enabling continued scaling with maintained precision.
Data Source
AI summary
A semiconductor structure and a method of manufacturing a semiconductor structure are provided. The method includes forming an insulation structure over a semiconductor substrate, the insulation structure defining a trench having a trench width. The method also includes forming a first conductive material layer in the trench and over an upper surface of the insulation structure, wherein a portion of the first conductive material layer over the upper surface of the insulation structure has a thickness of greater than half the trench width. The method further includes performing a planarization operation on the first conductive material layer to form a contact plug having a concave upper surface recessed from the upper surface of the insulation structure.