Multi-Zone Gas Distribution Plate for Wafer Etching Uniformity
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Solution Overview
Problem
Existing gas distribution plates (GDPs) in plasma-based processes fail to achieve uniform plasma distribution and etching uniformity, particularly in high-standard processes like through-silicon via (TSV) and deep silicon etching, due to their isotropic design and inability to compensate for non-uniformities caused by the layout of gas inlets, outlets, and RF inlets.
Innovation Solution
A redesigned GDP with multiple zones, where holes are grouped differently based on the positions of gas inlets, outlets, and RF inlets, allowing for customized gas flow and etching rates across the wafer surface to compensate for non-uniformities.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If an isotropic GDP design is used, then the device complexity is low and ease of manufacture is high, but the etching uniformity deteriorates and cannot meet high-standard process requirements
Solution Approach 1:
The GDP is divided into multiple zones (first zone, second zone, third zone) with different hole configurations. Each zone is designed independently with specific hole patterns, sizes, and densities tailored to compensate for non-uniformities in that particular region of the wafer, thereby achieving overall etching uniformity across the entire wafer surface.
Solution Approach 2:
Different regions of the GDP are assigned different properties: the first zone has holes with specific characteristics to address non-uniformity near the gas inlet, the second zone has different hole configurations for the gas outlet region, and the third zone has yet another configuration for the RF inlet region. This local customization of hole properties ensures that each zone compensates for its specific non-uniformity pattern.
2Manufacturing precision
If an isotropic GDP design is used, then the device complexity is low, but the plasma distribution uniformity deteriorates
Solution Approach 1:
The GDP design transitions from an isotropic (symmetric) pattern to an asymmetric multi-zone pattern where hole distributions, sizes, and densities vary by zone. The first zone has a different hole pattern than the second zone, which differs from the third zone, creating an asymmetric configuration that actively compensates for the asymmetric non-uniformities introduced by gas inlet, gas outlet, and RF inlet positions.
Solution Approach 2:
The hole parameters (size, density, distribution pattern) are changed across different zones of the GDP. By varying these parameters locally in each zone, the plasma distribution is adjusted to achieve uniformity despite the presence of gas inlets, outlets, and RF inlets that create non-uniform conditions.
3Manufacturing precision
If a multi-zone GDP with customized hole patterns is implemented, then the etching uniformity improves to 9.3%, but the device complexity increases
Solution Approach 1:
The GDP manufacturing process is segmented into zone-specific hole patterning steps. Each zone (first, second, third zones) can be designed and manufactured with its specific hole configuration independently, allowing for specialized fabrication techniques to be applied to each zone according to its requirements while maintaining overall integration in a single GDP component.
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 redesigned GDP improves etching uniformity, achieving a uniformity of 9.3% compared to the previous 23.3%, meeting the stringent uniformity requirements of TSV and deep silicon etching processes.
Implementation Method 1
A plasma based process tool includes a housing defining a process chamber, a gas distribution plate arranged in the process chamber... The GDP is configured to distribute the process gas within the process chamber... The plasma is introduced into the process chamber and the wafer is etched using the plasma
Data Source
AI summary
Devices and methods for controlling wafer uniformity in plasma-based process is disclosed. In one example, a device for plasma-based processes is disclosed. The device includes: a housing defining a process chamber and a gas distribution plate (GDP) arranged in the process chamber. The housing comprises: a gas inlet configured to receive a process gas, and a gas outlet configured to expel processed gas. The GDP is configured to distribute the process gas within the process chamber. The GDP has a plurality of holes evenly distributed thereon. The GDP comprises a first zone and a second zone. The first zone is closer to the gas outlet than the second zone. At least one hole in the first zone is closed.