Radical Pretreatment and Annealing for Low-Resistance BEOL Substrates
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Solution Overview
Problem
Semiconductor substrates face limitations such as high sheet resistances and limited gap fill, particularly at the back end of line (BEOL), necessitating improved methods for reducing sheet resistance, enhancing gap fills, and increasing grain sizes.
Innovation Solution
A method involving a radical treatment operation in a first chamber followed by an annealing operation in a second chamber, both coupled to the same cluster tool, with specific temperature, pressure, and time parameters for each process, including pre-heating, exposure to species radicals, and thermal annealing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional processing methods are used at the back end of line (BEOL), then substrates can be processed, but sheet resistances remain high and gap fill is limited
Solution Approach 1:
The patent applies parameter changes by implementing a two-step process with specific temperature and pressure ranges: radical treatment at 20-300°C and 1-100 mTorr, followed by annealing at 200-450°C and 1-760 Torr. These controlled parameter variations enable reduced sheet resistance (below 0.5 ohms/square) and improved gap fill that cannot be achieved with conventional single-step processing
Solution Approach 2:
The processing method is segmented into two distinct operations: radical treatment in a first chamber followed by annealing in a second chamber. This segmentation allows each step to be optimized independently - the radical treatment modifies substrate properties while the annealing step completes the processing, thereby overcoming the limitations of conventional unified processing methods
2Manufacturing precision
If conventional processing methods are used at the back end of line (BEOL), then substrates can be processed, but gap fill is limited
Solution Approach 1:
The patent utilizes parameter changes with radical treatment conducted at low pressure (1-100 mTorr) and controlled temperature (20-300°C), followed by annealing at elevated pressure (1-760 Torr) and temperature (200-450°C). This parameter optimization enables superior gap fill performance that addresses the processing limitations of conventional BEOL methods
3Manufacturing precision
If conventional processing methods are used at the back end of line (BEOL), then substrates can be processed, but grain sizes remain low
Solution Approach 1:
The patent segments the processing into radical treatment followed by annealing, where the annealing step at 200-450°C for 1-60 minutes specifically promotes grain growth. This segmentation enables increased grain size that overcomes the processing limitations of conventional single-step methods at the BEOL
4Manufacturing precision
If radical treatment and annealing are conducted in separate chambers, then processing quality is improved, but device complexity increases
Solution Approach 1:
The patent merges the radical treatment chamber and annealing chamber into a single integrated processing system with a shared vacuum environment and substrate handling infrastructure. This merging maintains the quality benefits of separate processing steps while reducing device complexity and footprint compared to fully independent chamber systems
5Manufacturing precision
If radical treatment and annealing are conducted in separate chambers, then processing quality is improved, but system footprint is reduced
Solution Approach 1:
The patent combines radical treatment and annealing functions within a single integrated chamber system, sharing common vacuum infrastructure, substrate loading/unloading mechanisms, and control systems. This merging maintains high processing quality through controlled sequential operations while minimizing system footprint and reducing the number of discrete chamber components required
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 method achieves reduced sheet resistances, improved gap fills, and increased grain sizes while maintaining impurity levels, facilitating efficient processing on a single integrated cluster tool with reduced footprint and cost.
Implementation Method 1
exposing the substrate to species radicals. The exposing of the substrate to the species radicals includes a treatment temperature that is less than 350 degrees Celsius, a treatment pressure that is less than 1.0 Torr
Implementation Method 2
annealing the substrate after the exposing of the substrate to the species radicals. The annealing includes exposing the substrate to molecules, an anneal temperature that is 300 degrees Celsius or greater
Data Source
AI summary
Aspects of the present disclosure relate to methods, systems, and apparatus for conducting a radical treatment operation on a substrate prior to conducting an annealing operation on the substrate. In one implementation, a method of processing semiconductor substrates includes pre-heating a substrate, and exposing the substrate to species radicals. The exposing of the substrate to the species radicals includes a treatment temperature that is less than 300 degrees Celsius, a treatment pressure that is less than 1.0 Torr, and a treatment time that is within a range of 8.0 minutes to 12.0 minutes. The method includes annealing the substrate after the exposing of the substrate to the species radicals. The annealing includes exposing the substrate to molecules, an anneal temperature that is 300 degrees Celsius or greater, an anneal pressure that is within a range of 500 Torr to 550 Torr, and an anneal time that is less than 4.0 minutes.