Plasma Processing Apparatus Grounding Electrode Segmentation
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Solution Overview
Problem
Next-generation vertical NAND flash memory devices require high aspect ratio etching with precise control of Skew-Critical Dimension (SCD) due to increased separation between stacked stages, where RF power sources generate harmonics causing inconsistencies in plasma density and etch rate, leading to challenges in managing SCD effectively.
Innovation Solution
The plasma processing apparatuses feature a grounding electrode with adjustable area facing the RF plate, a conductor ring insulated from the lower electrode and RF plate surrounding the side walls, and a baffle unit spaced apart from the conductor ring to control the etching amount for central and edge portions of the wafer, improving etch rate reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If RF power source is used to generate plasma, then plasma generation is achieved, but harmonics are generated causing inconsistencies in plasma density and etch rate
Solution Approach 1:
The grounding electrode is divided into multiple segments (first grounding electrode and second grounding electrode) that can be independently adjusted. This segmentation allows selective modification of the grounding area to compensate for harmonic effects and achieve uniform plasma density and etch rate across the wafer surface.
Solution Approach 2:
The patent applies different grounding electrode configurations to different regions of the RF plate. By adjusting the area of the grounding electrode facing specific portions of the RF plate, local plasma density and etch rate can be optimized to counteract harmonic-induced inconsistencies.
2Productivity
If stacked stages are increased in vertical NAND flash memory devices, then device capacity is improved, but separation between stacked stages increases requiring precise SCD control
Solution Approach 1:
The grounding electrode area is made adjustable rather than fixed. This dynamic configuration allows real-time optimization of plasma distribution to maintain precise SCD control as device complexity and stacked stage separation increase.
3Reliability
If grounding electrode area is adjusted to control etching amount, then etch rate uniformity is improved, but device complexity increases
Solution Approach 1:
The grounding electrode is segmented into multiple independent sections (first and second grounding electrodes) that can be individually adjusted. This segmentation provides a practical way to control etch rate uniformity without requiring complete redesign of the entire electrode system.
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
These configurations effectively control the etching amount for both central and edge portions of the wafer, enhancing the reliability of plasma etching processes by adjusting the grounding electrode area, conductor ring arrangement, and baffle unit positioning, thereby optimizing the overall etch rate.
Implementation Method 1
A radio frequency (RF) power source used to generate plasma during certain semiconductor fabrication processes
Implementation Method 2
A radio frequency (RF) power source used to generate plasma
Data Source
AI summary
A plasma processing apparatus includes; a chamber, a lower electrode disposed within the chamber and including a lower surface and an opposing upper surface configured to seat a wafer, an RF rod disposed on the lower surface of the lower electrode and extending in a vertical direction. The RF plate includes a first portion contacting the lower surface of the lower electrode, a second portion protruding from the first portion towards the RF rod, and a third portion extending from the second portion to connect the RF rod. A grounding electrode is spaced apart from the RF plate and at least partially surrounds a side wall of the RF rod and a side wall of the second portion of the RF plate. The grounding electrode includes a first grounding electrode facing each of the side wall of the RF rod and the second portion of the RF plate, and a second grounding electrode at least partially surrounding the first grounding electrode, and configured to horizontally rotate.