Plasma Etching Voltage Control for Mask-Safe Fine-Pitch Patterning
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Solution Overview
Problem
Existing plasma etching technologies face challenges in preventing the mask from being etched, achieving high-aspect ratio contact (HARC) etching, and performing fine-pitch etching with high yield.
Innovation Solution
A plasma etching apparatus with a voltage application unit that applies different direct current (DC) voltages to the wafer, creating an electric field that accelerates plasma particles through the mask pattern holes, thereby preventing mask etching and enhancing etching precision and yield.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional plasma etching is used, then etching can be performed on the substrate, but the mask gets etched along with the substrate reducing yield
Solution Approach 1:
The patent applies different voltages to different regions of the mask layer. A first voltage is applied to a first region of the mask layer while a second voltage is applied to a second region of the mask layer. This creates localized electric fields that selectively accelerate plasma particles to specific regions, enabling precise control over where etching occurs and preventing unwanted mask etching in protected regions.
2Speed
If high energy plasma particles are used for etching, then etching speed increases, but mask etching occurs reducing precision
Solution Approach 1:
The patent changes the energy parameter of plasma particles by applying different voltages to different regions of the mask layer. This creates regions with different plasma particle energies, allowing high-energy particles to etch quickly in designated areas while low-energy particles preserve the mask in protected areas, thus achieving both high etching speed and high pattern accuracy.
3Manufacturing precision
If uniform voltage is applied to the mask layer, then simple control is achieved, but fine-pitch etching with high yield cannot be achieved
Solution Approach 1:
The patent segments the voltage application system into multiple independent voltage sources. Each voltage source can be independently controlled and applied to specific regions of the mask layer. This segmentation enables precise control over plasma particle acceleration in different areas, making fine-pitch etching with high yield achievable despite the increased system complexity.
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 solution effectively prevents mask etching, increases the yield of HARC etching, and enables fine-pitch etching, improving the overall efficiency and precision of the semiconductor fabrication process.
Implementation Method 1
applying a voltage to the mask layer. When the voltage is applied to the mask layer, a particle of the plasma that passes through the mask layer may be accelerated toward the etch-target layer
Implementation Method 2
forming a plasma on the wafer
Implementation Method 3
a particle of the plasma that passes through the mask layer may be accelerated toward the etch-target layer
Data Source
AI summary
A plasma etching apparatus includes a chuck configured to support a wafer, and a voltage application unit. The voltage application unit includes a first voltage application part configured to apply a first voltage to the wafer on the chuck, and a second voltage application part configured to apply a second voltage to the wafer on the chuck, the second voltage being different from the first voltage.