Plasma Processing Table Dielectric Layer Uniformity
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Solution Overview
Problem
Plasma processing systems face challenges in achieving uniformity across semiconductor wafers due to non-uniform electric field distributions caused by high-frequency RF power, leading to variations in etching rates and poor within-wafer uniformity.
Innovation Solution
A plasma processing table with a conductive member and two dielectric layers, where a first dielectric layer with a relative constant of 3.5 to 8.5 is embedded in the center to reduce field strength and a second dielectric layer with a relative constant of 100 or more is applied at the edge to prevent high-frequency current leakage, allowing for efficient cavity cylindrical resonance and uniform electric field application.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a dielectric with relative dielectric constant of 3.5 to 8.5 is embedded in the center of the electrode to obtain uniform field strength distribution, then within-wafer uniformity is improved, but high-frequency current leaks to the outside of the wafer causing non-uniform etching rate
Solution Approach 1:
The patent applies different dielectric materials with different properties to different regions of the electrode. The first dielectric layer (with lower dielectric constant of 3.5-8.5) is placed at the center to reduce field strength and improve uniformity, while the second dielectric layer (with higher dielectric constant of 100 or more) is placed at the edge to prevent current leakage. This local differentiation of material properties resolves the contradiction by addressing different problems in different regions.
2Quantity of substance
If high-frequency RF power is applied to produce plasma, then electron density is increased, but field strength becomes non-uniform with higher strength at center and lower at edges
Solution Approach 1:
The patent changes the dielectric constant parameter of the electrode structure by introducing two different dielectric layers. The first dielectric layer with lower dielectric constant (3.5-8.5) reduces the field strength at the center where it is naturally higher, while the second dielectric layer with higher dielectric constant (100+) at the edge prevents field strength from dropping too low. This parameter modification allows maintaining high electron density while achieving uniform field strength distribution.
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 enhances within-wafer uniformity by maintaining high electric potential at the center and preventing current leakage, resulting in improved plasma etching uniformity across the substrate.
Implementation Method 1
a first dielectric layer formed on the electrically conductive member so that it covers the center of the upper surface of the electrically conductive member, serving to make a high-frequency electric field to be applied to plasma via the substrate uniform
Implementation Method 2
a second dielectric layer having a relative dielectric constant of 100 or more, formed on the electrically conductive member so that it is in contact at least with the edge of the substrate, in order to prevent the high-frequency current that has propagated along the electrically conductive member face from leaking to the outside of the substrate
Implementation Method 3
RF (radio frequency) power is applied to the space between the two electrodes to make a process gas fed to the system into plasma
Implementation Method 4
the high-frequency current can flow deeper than in the other part and causes cavity cylindrical resonance of TM mode
Data Source
AI summary
Disclosed herein is a table 2 for use in a plasma processing system 1 that includes an electrically conductive member serving as a lower electrode 21 for plasma formation, a lower dielectric layer 22 (first dielectric layer) formed on the electrically conductive member so that it covers the center of the upper surface of the electrically conductive member, serving to make a high-frequency electric field to be applied to plasma via a substrate uniform, and an upper dielectric layer 24 (second dielectric layer) having a relative dielectric constant of 100 or more, formed on the electrically conductive member so that it is in contact at least with the edge of the substrate, in order to prevent a high-frequency current that has propagated along the electrically conductive member face from leaking to the outside of the substrate (wafer W).