Molybdenum Trench Conductor Structure for Seam-Free CMP
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Solution Overview
Problem
The miniaturization of MOS-FETs in semiconductor devices leads to deterioration in operational properties, and existing technologies face challenges in preventing seam formation, melting, and residue issues during chemical mechanical polishing (CMP), affecting the reliability and performance of these devices.
Innovation Solution
A semiconductor device design that includes a conductive structure with a liner interposed between the mold layer and the conductive layer, where the liner has a base and sidewall portion, and the conductive layer is formed with molybdenum (Mo) and oxygen (O), preventing seam formation and improving stability during CMP processes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If MOS-FET sizes are decreased to meet the demand for small pattern size, then the pattern size is reduced, but the operational properties of the semiconductor device deteriorate
Solution Approach 1:
The conductive layer is divided into upper and lower portions with different compositions. The lower portion contains Mo and O to prevent seam formation and improve CMP stability, while the upper portion is pure Mo to maintain low resistance. This segmentation allows each portion to optimize for its specific function, resolving the contradiction between miniaturization and operational reliability.
2Ease of manufacture
If conventional conductive layers are used without liner, then the process is simpler, but seam formation occurs and CMP stability is poor
Solution Approach 1:
A liner layer is introduced as an intermediary between the mold layer and the conductive layer. This liner prevents direct contact between the conductive layer and mold layer, thereby preventing seam formation and improving CMP stability. The liner acts as a mediator that resolves the manufacturing precision issues without significantly complicating the overall process.
3Reliability
If the conductive layer is made thinner to reduce resistance, then the electrical resistance decreases, but the layer becomes more prone to seam formation and CMP issues
Solution Approach 1:
The conductive layer is designed as a composite structure with two portions: the lower portion contains Mo and O to provide seam prevention and CMP stability, while the upper portion is pure Mo to maintain low electrical resistance. This composite material approach allows the thin conductive layer to achieve both low resistance and resistance to seam formation and CMP issues.
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
The solution stabilizes the formation of the conductive layer, increases its mean grain size, reduces electric resistance, and enhances the reliability and performance of semiconductor devices by preventing seam formation and melting issues during CMP, thereby improving electrical and reliability characteristics.
Implementation Method 1
A liner interposed between a mold layer and a conductive layer of the semiconductor device can facilitate the stable formation of the conductive layer in which a seam is prevented from forming
Implementation Method 2
The conductive layer and the liner may include molybdenum (Mo), and the liner may further include oxygen (O)
Data Source
AI summary
A semiconductor device includes a mold layer defining a trench and a conductive structure disposed on the trench. The conductive structure includes a conductive layer and a liner, and the conductive layer includes upper and lower portions. The liner includes a base portion and a sidewall portion on the base portion, and the upper portion of the conductive layer is disposed at a level higher than the sidewall portion of the liner. The sidewall portion of the liner is interposed between the lower portion of the conductive layer and the mold layer, and a top surface of the base portion of the liner is in contact with a bottom surface of the lower portion of the conductive layer. A width of the sidewall portion of the liner may decrease as a level increases.