Fin Gate Opening Etch to Minimize Lateral Undercut
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Solution Overview
Problem
The complexity of processing and manufacturing semiconductor integrated circuits (ICs) has increased due to scaling down processes, necessitating improvements in manufacturing efficiency and cost reduction.
Innovation Solution
A method for forming a semiconductor device structure involving the formation of fin structures, deposition of gate dielectric and electrode layers, and a controlled etching process to create openings with a faster etch rate for the gate dielectric layer relative to the gate electrode layer, followed by filling with dielectric material.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a conventional etching process is used to form openings through the gate electrode layer and gate dielectric layer, then the openings can be formed, but lateral undercut occurs which increases effective capacitance and reduces device performance
Solution Approach 1:
The patent applies parameter changes by modifying the etching process parameters - specifically using a multi-step etching process with different etchants and conditions. The first etching step uses parameters optimized for removing gate electrode material, while the second etching step uses parameters optimized for removing gate dielectric material. This parameter differentiation allows precise control over the etching rate for each layer, minimizing lateral undercut and reducing effective capacitance while maintaining manufacturing precision for opening formation.
2Ease of manufacture
If the etching rate of gate dielectric layer is not differentiated from gate electrode layer, then the process is simpler, but lateral undercut increases and manufacturing precision decreases
Solution Approach 1:
The patent applies segmentation by dividing the etching process into two distinct steps: a first etching step that removes gate electrode material and a second etching step that removes gate dielectric material. Each step uses specifically tailored etchants and process parameters optimized for the respective material. This segmentation of the etching process enables precise control over the removal of each layer independently, achieving high manufacturing precision for opening formation while managing the complexity through a systematic multi-step approach.
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 reduces effective capacitance and improves device performance by minimizing lateral undercut and enhancing manufacturing precision.
Implementation Method 1
performing an etch process that etches the gate dielectric layer at a faster rate than the gate electrode layer
Data Source
AI summary
Embodiments of the present disclosure provide a method for forming a semiconductor device structure. The method includes forming a fin structure over a substrate, forming an insulating material adjacent the fin structure, depositing a gate dielectric layer over the fin structure and the insulating material, depositing a gate electrode layer on the gate dielectric layer, forming an opening through the gate electrode layer and the gate dielectric layer into the insulating material, then performing an etch process that etches the gate dielectric layer at a faster rate than the gate electrode layer, and filling the opening with a dielectric material.