Graphitized Carbon Black Absorber Layer for Uniform Substrate Annealing
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Solution Overview
Problem
Conventional absorber layers used in substrate annealing processes, such as amorphous carbon, experience property changes and uneven heating due to varying thermal absorption properties across substrate surfaces, making uniform heating challenging in integrated circuit fabrication.
Innovation Solution
A method using an absorber layer comprising graphitized carbon black, finely milled graphite, or fullerene, applied at a lower temperature and remaining stable during high-temperature annealing, providing a uniform thermal absorption coefficient across the substrate surface.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If amorphous carbon layer is deposited at low temperature, then the deposition process is simple and economical, but the thermal absorption coefficient is insufficient and properties change during annealing
Solution Approach 1:
The patent changes the material parameters by using graphitized carbon black instead of amorphous carbon, and controls the deposition temperature parameter to be between 25-100°C, ensuring the absorber layer maintains stable thermal absorption properties during subsequent high-temperature annealing processes
Solution Approach 2:
The patent employs composite material strategy by using graphitized carbon black particles suspended in a carrier solution, combining the high thermal absorption stability of graphitized carbon with the applicability benefits of liquid suspension deposition
2Device complexity
If conventional absorber layers are used, then the deposition method is simple, but uniform heating across substrate surface cannot be achieved
Solution Approach 1:
The patent applies local quality principle by ensuring the absorber layer uniformly covers the entire substrate surface including all patterned regions, providing consistent thermal absorption properties across different areas with varying device densities, thus achieving uniform heating throughout the substrate
3Productivity
If rapid thermal processing is used, then heating rate is high and productivity is improved, but uneven heating occurs due to substrate patterns
Solution Approach 1:
The patent introduces an intermediary absorber layer between the electromagnetic radiation source and the substrate patterns. This layer absorbs radiation uniformly across the entire substrate surface and converts it to heat, acting as a mediator that eliminates the uneven heating caused by varying reflectivities of different substrate patterns while maintaining rapid heating capability
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 ensures uniform and stable heating across the substrate surface during annealing, maintaining the thermal properties of the absorber layer and preventing unwanted diffusion and damage, thus improving the efficiency of the annealing process in integrated circuit fabrication.
Implementation Method 1
exposing the substrate to electromagnetic radiation have one or more wavelengths between about 600 nm and about 1000 nm under conditions sufficient to heat the layer to a temperature of at least about 300 °C
Implementation Method 2
A top layer of the substrate may be heated to a temperature between 1100°C to about 1410°C, and cooled down to near ambient temperature in a time on the order of 1 millisecond
Data Source
Figure 1
Figure 2
Figure 3A~3F
AI summary
The present invention generally provides an absorber layer (312) using carbon based materials with increased and stabled thermal absorption coefficient and economical methods to produce such an absorber layer (312). One embodiment of the present invention provides a method for processing a substrate (12; 214; 300; 420) comprising depositing an absorber layer (312) on a top surface of the substrate (12; 214; 300; 420), wherein the substrate (12; 214; 300; 420) is maintained under a first temperature, annealing the substrate (12; 214; 300; 420) in a thermal processing chamber (14; 412), wherein the substrate (12; 214; 300; 420) is heated to a second temperature, and the second temperature is higher than the first temperature, and removing the absorber layer (312) from the substrate (12; 214; 300; 420).