Plasma Generation Current Divider for Uniform Etch
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Solution Overview
Problem
In semiconductor manufacturing, plasma etching processes using Inductively Coupled Plasma (ICP) sources with multiple coils can result in uneven etch rates between the central and edge regions of substrates due to plasma density imbalances, caused by current dividers and RF power supply configurations.
Innovation Solution
A plasma generation apparatus with a current divider system, comprising a high-frequency power supply, first and second antennas connected in parallel, and capacitors (including variable capacitors) that adjust resonance and current ratios to distribute electric current evenly, ensuring uniform etch rates across the substrate.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If a current divider is provided between the RF power supply and the coils to perform etching on the entire substrate region, then the etching process can be applied to the entire substrate, but there is a difference in etch rate between the central region and the edge region due to plasma density imbalance
Solution Approach 1:
The patent applies local quality by providing different capacitance values to different antenna groups. Specifically, the first antenna group connected to the first coil has a first capacitance value, while the second antenna group connected to the second coil has a second capacitance value that is different from the first. This allows different regions of the substrate to receive plasma with appropriate density characteristics, achieving uniform etch rates across the entire substrate area.
Solution Approach 2:
The patent changes the electrical parameter (capacitance) of the current divider to control plasma density distribution. By adjusting the capacitance values in the current divider circuit, the patent optimizes the current distribution to each antenna group, thereby controlling the plasma density in different regions of the chamber to achieve uniform etching across the substrate.
2Adaptability or versatility
If two or more coils receive power from one RF power supply through a current divider, then the etching process can be performed on the entire substrate region, but plasma density imbalance causes uneven etch rates between central and edge regions
Solution Approach 1:
The patent implements local quality by assigning different capacitance values to different antenna groups within the plasma generation unit. The first antenna group has a first capacitance value and the second antenna group has a second capacitance value, allowing each region to have optimized plasma characteristics for uniform etching across the entire substrate.
Solution Approach 2:
The patent employs variable capacitors in the current divider circuit, allowing dynamic adjustment of capacitance values. This enables real-time optimization of plasma density distribution and current allocation to different antenna groups, maintaining stable and uniform plasma composition across the substrate processing area.
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 controls plasma density and etch rates, providing a uniform etching process over the entire substrate region by adjusting capacitances in the current divider, thereby addressing the imbalance issues in existing ICP systems.
Implementation Method 1
The ICP type source applies an RF signal to one or more coils installed in a chamber and induces an electro-magnetic field in the chamber, thereby generating plasma
Implementation Method 2
The current divider includes a first capacitor disposed between the first antenna and the second antenna, a second capacitor connected with the second antenna in parallel, and a third capacitor connected with the second antenna in series
Data Source
AI summary
A substrate treating apparatus includes a chamber having a space therein in which a substrate is treated, a support unit that supports the substrate in the chamber, a gas supply unit that supplies gas into the chamber, and a plasma generation unit that excites the gas in the chamber into a plasma state. The plasma generation unit includes a high-frequency power supply, a first antenna connected to one end of the high-frequency power supply, a second antenna connected with the first antenna in parallel, and a current divider that distributes electric current to the first antenna and the second antenna. The current divider includes a first capacitor disposed between the first antenna and the second antenna, a second capacitor connected with the second antenna in parallel, and a third capacitor connected with the second antenna in series. The second capacitor and the third capacitor are implemented with a variable capacitor.