Segmented Grid Electrodes for Uniform Wafer Plasma Etching
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Solution Overview
Problem
Semiconductor wafer processing equipment faces challenges with plasma-induced damage (PID) and wafer charging by ions, and existing methods for improving plasma distribution are imprecise and limited in controlling the dispersion between the center and edge of the wafer.
Innovation Solution
A semiconductor wafer processing apparatus with a plasma chamber, processing chamber, and ion extraction device featuring grid electrodes with through-holes and reflector plates, where different potential differences are applied to electrode plates to control plasma distribution and neutralize ions, using an inductively coupled plasma antenna for uniform plasma generation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If ion beam equipment is used for etching, then directional etching capability is improved, but plasma-induced damage and wafer charging occur
Solution Approach 1:
A reflector is introduced as an intermediary component between the ion extraction device and the wafer. The reflector neutralizes ions through electron attachment, converting harmful ion beams into neutral particle beams that maintain directional etching capability while eliminating plasma-induced damage and wafer charging effects
2Stability of the object's composition
If electrostatic chuck rotation or ICP antenna is used to improve plasma distribution, then plasma uniformity is improved, but control precision is insufficient
Solution Approach 1:
The grid electrodes are segmented into multiple independently controllable regions. By applying different voltages to different segments of the grid electrodes, precise control over ion extraction and plasma distribution is achieved, enabling independent optimization of plasma uniformity across different wafer regions
Solution Approach 2:
Different voltage potentials are applied to different regions of the grid electrodes to create localized electric field distributions. This allows tailored control of ion extraction in specific areas, achieving precise plasma distribution uniformity that matches the specific requirements of different wafer regions
3Measurement precision
If multiple grid electrodes with different potentials are used, then plasma distribution control is improved, but device complexity increases
Solution Approach 1:
The grid electrode structure serves multiple functions simultaneously: it extracts ions from plasma, accelerates them toward the wafer, and enables precise spatial control of ion distribution through segmented voltage application. The reflector also provides neutralization while maintaining beam directionality, reducing the need for separate components
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 apparatus achieves precise control over plasma distribution and neutralizes ions, resolving plasma-induced damage and wafer charging issues, ensuring uniform etching rates across the wafer center and edge.
Implementation Method 1
using an inductively coupled plasma antenna for uniform plasma generation
Implementation Method 2
voltages having different potential differences are applied to the plurality of electrode plates, respectively
Implementation Method 3
configured to neutralize an ion beam extracted from the ion extraction device
Data Source
AI summary
A semiconductor wafer processing apparatus includes a plasma chamber, a processing chamber connected to the plasma chamber and including an electrostatic chuck configured to support a semiconductor wafer, a plurality of grid electrodes between the plasma chamber and the processing chamber, and through-holes extending through the plurality of grid electrodes, where the plurality of grid electrodes include a first grid electrode and a second grid electrode spaced apart from the first grid electrode in a direction from the plasma chamber to the processing chamber and at least one of the first grid electrode and the second grid electrode includes a plurality of electrode plates.