Atmospheric Pressure Plasma Annealing for Low-Thermal-Budget 3D ICs
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Solution Overview
Problem
The thermal budget required by multi-layer IC thermal annealing processing poses a significant barrier to 3D IC production, as high temperatures can damage underlying layers in monolithic 3D ICs.
Innovation Solution
A method involving implanting a substrate to create an ion implanted layer and annealing it using atmospheric pressure plasma, where only the top portion of the substrate is heated to a maximum temperature of 950°C, while the underlying layers are kept below 450°C to prevent damage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional thermal annealing processing is used to anneal ion implanted layers in multi-layer ICs, then the ion implanted layer can be effectively annealed, but the underlying layers are damaged due to excessive temperature
Solution Approach 1:
The patent applies local quality by creating a spatial temperature gradient where only the top portion of the substrate containing the ion implanted layer is heated to high temperature (up to 950°C), while the underlying layers are maintained at lower temperatures (below 450°C). This is achieved through atmospheric pressure plasma processing that confines thermal energy to the surface region, enabling selective annealing of the implanted layer without damaging previously formed underlying layers in monolithic 3D IC structures.
Solution Approach 2:
The patent changes the thermal budget parameters by limiting the maximum temperature of underlying layers to below 450°C and the top portion to below 950°C, compared to conventional annealing that uniformly heats the entire substrate to high temperatures. This parameter control enables effective annealing of the ion implanted layer while preserving the integrity of temperature-sensitive underlying layers.
2Stability of the object's composition
If the entire substrate is heated to high temperature for annealing, then uniform annealing is achieved, but the thermal budget is excessive and damages underlying layers
Solution Approach 1:
The patent implements local quality by creating a non-uniform temperature distribution across the substrate thickness, where the top portion experiences high temperature (below 950°C) for effective annealing while the underlying layers experience lower temperature (below 450°C). This localized thermal treatment achieves sufficient annealing uniformity in the implanted layer region without requiring uniform high temperature throughout the entire substrate, thereby reducing the overall thermal budget.
3Temperature
If atmospheric pressure plasma is used for annealing, then the thermal budget is controlled and underlying layers are protected, but the processing complexity increases
Solution Approach 1:
The patent replaces conventional thermal field annealing with atmospheric pressure plasma processing, which uses a different physical mechanism (plasma-surface interaction) to achieve annealing. This substitution allows for controlled thermal budget (top portion below 950°C, underlying layers below 450°C) through plasma parameter control rather than bulk thermal field control, enabling selective heating without requiring complex multi-zone furnace systems.
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 approach allows for effective annealing of the ion implanted layer without damaging the underlying substrate, enabling the production of 3D ICs by controlling the thermal budget and maintaining the integrity of previously applied layers.
Implementation Method 1
annealing the ion implanted layer comprising contacting a top surface of the substrate with a plasma at a pressure from about 300 Torr to about 1000 Torr for a period of time sufficient to heat a first portion of the substrate comprising the ion implanted layer to a maximum temperature of less than or equal to about 950° C.
Data Source
AI summary
Methods and apparatus for contacting a substrate with a plasma at a pressure from about 300 Torr to about 1000 Torr for a period of time sufficient to heat a top portion of the substrate having a depth of less than about 200 nm, to a temperature high enough for annealing, and the temperature of the substrate at a depth of greater than or equal to about 200 nm is less than or equal to about 450° C.