Nested Antenna Coils for Uniform Plasma Density in ICP Etching
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Solution Overview
Problem
Inductively Coupled Plasma (ICP) apparatuses face challenges in achieving uniform etching rates between the edge and central regions of the chamber, leading to inconsistent plasma density distribution.
Innovation Solution
The design incorporates a plasma generation unit with a first antenna inside a second antenna, where the second antenna features a stacked coil structure on the dielectric window to minimize contact area and enhance inductive coupling, thereby increasing plasma density in the edge region.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a conventional single antenna structure is used, then the device complexity is low, but the plasma density uniformity between edge and central regions deteriorates
Solution Approach 1:
The antenna system is segmented into multiple independent antenna units, each with its own coil structure. The first antenna unit has a first coil and the second antenna unit has a second coil, allowing independent control of plasma generation in different regions of the chamber. This segmentation enables separate adjustment of plasma density in edge and central regions to achieve uniformity.
Solution Approach 2:
The first antenna unit is disposed inside the second antenna unit, creating a nested configuration where the first coil is positioned within the region enclosed by the second coil. This nested arrangement allows the antenna system to generate plasma with improved radial uniformity by combining the effects of inner and outer coils, addressing the etching rate difference between edge and central regions.
2Manufacturing precision
If the second antenna contacts the dielectric window extensively, then the structural stability is high, but the capacitive coupling increases reducing plasma density
Solution Approach 1:
The second coil is configured with a three-dimensional structure that includes vertical stacking of coil segments. By extending the antenna structure in the vertical dimension rather than increasing horizontal contact area, the design reduces capacitive coupling with the dielectric window while maintaining structural stability through the stacked configuration.
Solution Approach 2:
The antenna system applies different structural characteristics to different regions: the first coil operates independently in the inner region, while the second coil's stacked segments are positioned to minimize dielectric window contact. This local optimization of antenna structure allows reduced capacitive coupling while maintaining overall system stability.
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 reduces capacitive coupling, increases inductive coupling, and ensures a more uniform plasma density distribution across the chamber, improving the etching process efficiency.
Implementation Method 1
a plasma generation unit exciting the gas within the treating space to generate plasma. The plasma generation unit includes: a radio frequency (RF) power supplying an RF signal; and a first antenna and a second antenna being supplied with the RF signal to generate the plasma from the gas supplied inside the treating space
Implementation Method 2
The Inductively Coupled Plasma apparatus converts a source material into the plasma using an induced electric field induced by an antenna
Implementation Method 3
The second antenna includes a plurality of coils, and the plurality of coils included in the second antenna are on the dielectric window and are arranged such that a contact area of the second antenna with the dielectric window is minimized
Data Source
AI summary
A substrate treating apparatus includes a chamber having a treating space therein, a substrate support unit supporting a substrate in the treating space, a gas supply unit supplying a gas into the treating space, and a plasma generation unit exciting the gas within the treating space to generate plasma. The plasma generation unit includes an RF power supplying an RF signal, and a first antenna and a second antenna being supplied with the RF signal to generate the plasma from the gas supplied inside the treating space. The first antenna is disposed at an inside of the second antenna. The coils included in the second antenna are stacked on each other at a second height, and coils included in the first antenna are stacked on each other at a first height, the second height being greater than the first height.