Reactive Ion Etching Apparatus Single RF Power Source
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Solution Overview
Problem
Conventional reactive ion etching apparatuses are costly and complex due to the use of two radio-frequency power sources to achieve uniform etching rates on large substrates, and they often require additional heating and cooling mechanisms.
Innovation Solution
A reactive ion etching apparatus with an electrostatic chuck having a pair of electrodes that applies DC voltage and superposed radio-frequency potential, utilizing capacitors with a capacitance ratio of 2.5 to 25 to adjust the bias potential distribution, allowing a single radio-frequency power source to achieve uniform etching across the substrate.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If two radio-frequency power sources are used to supply different frequencies to first and second electrodes, then a substantially uniform etching rate can be obtained over the entire substrate, but the apparatus cost increases and the arrangement becomes complicated
Solution Approach 1:
The patent combines two separate radio-frequency power sources into a single power source that supplies radio-frequency power to both the first electrode (inside electrode) and the second electrode (outside electrode) simultaneously. This merging eliminates the need for two separate power sources and their associated distribution systems, thereby simplifying the apparatus arrangement while maintaining the capability to achieve uniform etching rates across the substrate through coordinated control of the single power source.
2Manufacturing precision
If two radio-frequency power sources are used to supply different frequencies to first and second electrodes, then a substantially uniform etching rate can be obtained over the entire substrate, but the apparatus cost increases
Solution Approach 1:
The patent merges two separate radio-frequency power sources into one unified power source that can supply radio-frequency power to both electrodes. This consolidation reduces the number of components that need to be manufactured, installed, and maintained, thereby lowering the overall apparatus cost while preserving the functionality required to achieve uniform etching rates across large substrates.
3Temperature
If heating means and cooling means are built into the stage with electrostatic chuck, then substrate temperature can be controlled, but the apparatus arrangement becomes more complex
Solution Approach 1:
The patent makes the stage multi-functional by integrating heating means, cooling means, and electrostatic chuck functionality into a single unified stage structure. This allows the stage to simultaneously perform temperature control (heating and cooling) and substrate holding (electrostatic chuck) functions, thereby achieving comprehensive substrate temperature control without proportionally increasing apparatus complexity, as these functions are combined rather than added separately.
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 simplifies the apparatus arrangement, reduces costs, and maintains a uniform etching rate across the substrate, with in-plane uniformity improved to within ±3.5% or better, while allowing adjustment for different etching conditions.
Implementation Method 1
the stage being provided with an electrostatic chuck having a pair of electrodes so that, at the time of etching the to-be-processed substrate, DC voltage is applied to the pair of electrodes, whereby the to-be-processed substrate is electrostatically absorbed to the electrostatic chuck
Implementation Method 2
the radio-frequency power source is arranged to be connected, through a second output line, to the pair of electrodes so as to apply radio-frequency potential in a manner to be superposed on the DC voltage
Implementation Method 3
both a first capacitor and a second capacitor are interposed respectively in the first output line and the second output line; and a capacitance ratio of the first capacitor to the second capacitor is set to a range of 2.5 to 25
Implementation Method 4
a plasma generation means for generating inside the vacuum chamber a plasma which ionizes the introduced etching gas
Data Source
Figure 1
AI summary
There is provided a reactive ion etching apparatus which is capable of attaining a substantially uniform etching rate over the entire in-plane direction of a to-be-processed substrate and which is low in cost and simple in construction. The reactive ion etching apparatus (EM) of this invention has a stage (4) provided with an electrostatic chuck (42) having a pair of electrodes (42b, 42c). At the time of etching a to-be-processed substrate (W), by applying DC voltage to the pair of electrodes, the to-be-processed substrate is electrostatically absorbed to the electrostatic chuck. In this reactive ion etching apparatus (EM), a radio-frequency power source (E2) connected to the stage, through a first output line (L1), applies bias potential to the to-be-processed substrate. The radio-frequency power source is also arranged to be connected through a second output line (L2) to the pair of electrodes so as to apply radio-frequency potential in a manner to be superposed on the DC voltage. The first capacitor (C1) and the second capacitor (C2) are respectively interposed in the first output line and the second output line. A capacitance ratio of the first capacitor to the second capacitor is set to a range of 0.25 to 25.