MOSCAP Post Features Retard CMP Dishing
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Solution Overview
Problem
In the semiconductor industry, large area metal-oxide-semiconductor capacitors (MOSCAPs) face issues during fabrication in a gate last process, such as dishing in the metal electrode leading to lower gate heights and shifts in capacitance-voltage characteristics, which degrades device yield and depth of focus in metal interconnect structures.
Innovation Solution
Incorporating post features in the material layer stack of MOSCAPs and transistors that retard chemical mechanical polishing processes while minimizing capacitance loss, these features are designed to maintain electrode heights and prevent dishing, thereby improving device performance and yield.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If post features are added to MOSCAP structure, then dishing is reduced and electrode heights are maintained, but device structure becomes more complex
Solution Approach 1:
The patent merges the post features with the existing MOSCAP fabrication process by forming them using the same material deposition and patterning steps as the metal electrode. The post features are created as part of the same layer stack, eliminating the need for separate processing steps and reducing overall device complexity despite the additional structural element.
Solution Approach 2:
The post features serve multiple functions: they act as polishing rate modifiers to prevent dishing, serve as structural support elements, and can function as etch stop layers or adhesion promoters. This multi-functionality reduces the need for additional dedicated structures, thereby limiting the increase in device complexity.
2Manufacturing precision
If post features are used to retard polishing, then dishing is prevented, but capacitance loss may occur
Solution Approach 1:
The patent carefully controls the parameters of the post features, including their height, width, spacing, and material composition, to optimize the balance between polishing retardation and capacitance preservation. By adjusting these parameters, the design minimizes the area occupied by post features while maintaining sufficient height differential to prevent dishing, thereby reducing capacitance loss.
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 post features effectively reduce dishing and maintain electrode heights, enhancing device performance by preventing capacitance loss and improving device yield, while being compatible with conventional manufacturing processes without significant additional costs.
Implementation Method 1
Incorporating post features in the material layer stack of MOSCAPs and transistors that retard chemical mechanical polishing processes
Data Source
AI summary
An integrated circuit device and methods of manufacturing the same are disclosed. In an example, integrated circuit device includes a gate structure disposed over a substrate; a source region and a drain region disposed in the substrate, wherein the gate structure interposes the source region and the drain region; and at least one post feature embedded in the gate structure.