Stepped Electrostatic Chuck Structure for Uniform Plasma Etching
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Solution Overview
Problem
Semiconductor processing equipment for plasma processing faces challenges in minimizing ion tilting due to non-uniform plasma density, leading to variable etching rates and high aspect ratio contact (HARC) profile tilts.
Innovation Solution
The equipment incorporates a substrate supporting structure with a lower electrode having a stepped design, where the processing area has a maximum height at the central portion and a tilt of 0.01 or less, and includes ceramic plates and an attraction electrode to manage electric field vectors and ion incidence, minimizing ion tilting.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a conventional flat lower electrode is used, then the device structure is simple, but ion tilting occurs due to non-uniform plasma density leading to variable etching rates and HARC profile tilts
Solution Approach 1:
The lower electrode is designed with a stepped structure where the processing area has a maximum height at the central portion and slopes downward toward the edges. This creates different local heights (central area versus edge area) that generate corresponding different electric field vectors, with vertical components at the center and tilted components at the edges, thereby compensating for non-uniform plasma density and minimizing ion tilting to achieve uniform etching across the substrate surface
Solution Approach 2:
The lower electrode employs an asymmetric stepped design rather than a symmetric flat structure. The processing area features a central peak with slopes descending toward the edges, creating an asymmetric height distribution. This asymmetry generates asymmetric electric field vectors that specifically counteract the non-uniform plasma density distribution, directing ions perpendicular to the substrate surface and eliminating HARC profile tilts
2Manufacturing precision
If the lower electrode has a stepped design with maximum height at center, then ion tilting is minimized, but the manufacturing complexity increases
Solution Approach 1:
The lower electrode's height parameter is deliberately changed across different spatial locations to create the stepped structure. The central portion has maximum height while edge areas have reduced heights, forming slopes. This parameter variation in the electrode geometry generates the required electric field distribution that minimizes ion tilting and ensures uniform HARC profiles, accepting the increased manufacturing complexity as necessary for achieving the desired processing precision
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 configuration minimizes ion tilting, ensuring uniform plasma processing and reducing HARC profile tilts, thereby enhancing processing efficiency and consistency.
Implementation Method 1
Electric field vectors in different directions are generated in the processing area
Implementation Method 2
substrate supporting structure supports a substrate
Data Source
AI summary
Semiconductor processing equipment and an electrostatic chuck include a semiconductor having: an upper electrode; a gas supplier connected to the upper electrode; and a substrate supporting structure spaced apart from the upper electrode to define a processing volume. The substrate supporting structure supports a substrate and includes: a lower electrode having a side area disposed outside a step formed at an outer perimeter portion of the lower electrode and a processing area disposed inside the step; a first plate disposed on the lower electrode; an attraction electrode disposed on the first plate; and a second plate disposed on the attraction plate. The second plate supports the substrate in a state in which the substrate is laid on an upper surface of the second plate. Each of the first plate and the second plate includes ceramic. The lower electrode has a maximum height at a central portion of the processing area.