Selective Epitaxial Film Formation via Separate Injection Paths
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Solution Overview
Problem
Existing selective deposition processes in semiconductor manufacturing often experience violent reactions between precursor and etchant gases, leading to premature reactant breakdown, equipment damage, and substrate contamination due to exothermic interactions in confined flow paths.
Innovation Solution
The process and equipment design separate the precursor and etchant flow paths, ensuring they intersect only within the reaction chamber's mixing space, avoiding high-pressure interactions and exothermic reactions upstream, and using inert gases to dilute and moderate the reaction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If precursor and etchant gases are supplied through common flow paths upstream of the reaction chamber, then the deposition process can proceed, but violent exothermic reactions occur leading to premature reactant breakdown, equipment damage, and substrate contamination
Solution Approach 1:
The common flow path is segmented into separate flow paths for precursor and etchant gases. The precursor is supplied through a first flow path while the etchant is supplied through a second flow path, preventing their premature mixing upstream of the reaction chamber. This segmentation eliminates the violent exothermic reactions that occur when they mix in confined upstream spaces, while still allowing both reactants to reach the substrate for deposition.
Solution Approach 2:
The harmful interaction between precursor and etchant gases is extracted from the upstream flow paths by providing separate inlet ports directly into the reaction chamber. The precursor and etchant are introduced separately at the reaction chamber level, removing the dangerous exothermic reaction zone from the upstream gas delivery system and preventing equipment damage and substrate contamination.
2Reliability
If separate flow paths are used for precursor and etchant, then violent reactions are avoided, but the device complexity increases due to additional inlet ports and flow path management
Solution Approach 1:
The precursor and etchant gases are prepared separately in their respective flow paths before entering the reaction chamber. By pre-separating the gas streams and providing dedicated inlet ports, the system eliminates the need for complex upstream mixing manifolds while maintaining process stability. The separate flow paths allow independent control and optimization of each reactant delivery.
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 minimizes the risk of premature reactant breakdown, equipment damage, and substrate contamination, while maintaining selective deposition efficacy by controlling reaction conditions and reducing reactivity.
Implementation Method 1
A precursor for semiconductor deposition and a vapor etchant are separately introduced through separate flow paths into a reaction space... selectively forming the semiconductor layer on the first surface
Implementation Method 2
a vapor etchant are separately introduced through separate flow paths into the reaction space... wherein the substrate is exposed to the precursor and to the vapor etchant
Data Source
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AI summary
Methods and apparatuses for selective epitaxial formation of films separately inject reactive species (10, 20) into a CVD chamber (300). The methods are particularly useful for selective deposition using volatile combinations of precursors (10) and etchants (20). Formation processes include simultaneous supply of precursors (10) and etchants (20) for selective deposition, or sequential supply for cyclical blanket deposition and selective etching. In either case, precursors (10) and etchants (20) are provided along separate flow paths that intersect in the relatively open reaction space (340), rather than in more confined upstream locations.