Gate Structure Step Height Removal for Uniform Contact Hole Depth
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Solution Overview
Problem
Inconsistent depth of gate plugs during the integrated process of fabricating source/drain plugs and gate plugs leads to electrical defects due to incomplete contact with the gate structure.
Innovation Solution
A method involving the formation of a composite material layer with an etching stop layer, a sacrifice layer, and a metal-containing layer on a gate structure, followed by the creation of a step height and subsequent wet etching to remove the step height and form a contact hole with sufficient depth.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If wet etching is performed directly on the gate structure without removing the step height first, then the etching process can proceed, but the etching speed becomes inconsistent and the contact hole depth cannot be uniformly controlled
Solution Approach 1:
The step height is removed in advance through a dedicated wet etching process before forming the contact hole. This preliminary removal of the step height ensures that the gate structure surface is uniform, allowing subsequent contact hole etching to proceed at consistent speeds and achieve uniform depths across all contact holes.
2Manufacturing precision
If the step height is removed before forming the contact hole, then the contact hole depth can be uniformly controlled, but additional etching steps are required
Solution Approach 1:
The step height removal is performed as a preliminary step before contact hole formation. Although this adds a process step, it prevents subsequent etching inconsistencies and reduces the need for rework or additional compensation steps, ultimately maintaining fabrication efficiency while ensuring contact hole uniformity.
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 method ensures that the gate plug formed in the contact hole can consistently contact the gate structure, thereby preventing electrical defects and ensuring reliable interconnections in semiconductor devices.
Implementation Method 1
a wet etching is performed to remove the step height
Data Source
AI summary
A method of removing a step height on a gate structure includes providing a substrate. A gate structure is disposed on the substrate. A dielectric layer covers the gate structure and the substrate. Then, a composite material layer is formed to cover the dielectric layer. Later, part of the composite material layer is removed to form a step height disposed directly on the gate structure. Subsequently, a wet etching is performed to remove the step height. After the step height is removed, the dielectric layer is etched to form a first contact hole to expose the gate structure.