Low-Halide Lanthanum Precursors via Three-Zone Purification
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Solution Overview
Problem
Existing lanthanum precursors used in semiconductor manufacturing contain high levels of halide impurities, which lead to contamination and device failure in microelectronics applications, necessitating the development of high-purity precursors with trace metals and halides below single ppm levels.
Innovation Solution
A method and system for purifying lanthanide amidinate compounds using a three-zone purification process involving sublimation, condensation, and cooling to achieve halide impurities below 10.0 ppm, preferably 5.0 ppm, and trace metals below 50.0 ppm, utilizing a sublimer, condenser, and cooler with optional separation units to separate volatile and non-volatile impurities.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional purification methods (crystallization and sublimation) are used to purify lanthanum precursors, then some halide removal is achieved, but the halide contamination levels remain above 10.0 ppm due to the limitations of these traditional methods
Solution Approach 1:
The patent employs a multi-stage purification process utilizing phase transitions including sublimation, condensation, and filtration. The precursor undergoes sublimation to separate volatile components, followed by condensation to collect purified material, and filtration to remove particulate contaminants. This sequence of phase transitions achieves halide contamination levels below 10.0 ppm, overcoming the limitations of conventional single-stage purification methods.
2Ease of manufacture
If lanthanum halides are used as starting materials to prepare lanthanum precursors, then the precursor synthesis is straightforward, but halide impurities are introduced and contaminate the final product
Solution Approach 1:
The patent systematically removes halide impurities through multiple extraction mechanisms: (1) selective sublimation that separates volatile halide compounds from the precursor, (2) condensation that collects purified material while leaving halides behind, and (3) filtration that physically removes halide-containing particulates. This multi-stage extraction process effectively eliminates halide contamination while maintaining precursor synthesis feasibility.
Solution Approach 2:
The patent introduces an intermediary purification system consisting of sublimation apparatus, condensation chambers, and filtration media. This intermediary process train acts as a mediator between the crude precursor synthesis and the final high-purity product, capturing and removing halide impurities without affecting the precursor synthesis route itself.
3Ease of operation
If halide impurities are present in lanthanum precursors, then the precursor can be easily delivered to deposition tools, but the halides migrate during deposition and cause corrosion and device failure
Solution Approach 1:
The patent performs preliminary purification action before precursor delivery to deposition tools. The multi-stage purification process (sublimation, condensation, filtration) is conducted upstream in the synthesis workflow, removing halide impurities before the precursor is loaded into delivery systems. This preliminary removal prevents halide migration and corrosion during subsequent deposition operations, ensuring device reliability while maintaining ease of 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
The process effectively reduces halide impurities to 10.0 ppm or less and trace metals to 50.0 ppm or less, enhancing the purity and reliability of lanthanum-containing films for semiconductor applications.
Implementation Method 1
heating the crude lanthanum amidinate material contained in the at least one sublimer in zone 1 to get crude lanthanum amidinate material vapor separated from the halide impurities and the trace amounts of non-volatile impurities
Implementation Method 2
passing the crude lanthanide amidinate material vapor from the zone 1 to the at least one condenser in zone 2 and condensing the crude lanthanide amidinate material vapor to form purified lanthanide amidinate material in the at least one condenser
Implementation Method 3
passing the non-condensed light impurity LnO(AMD)2 from the zone 2 into the at least one cooler in zone 3 to form solid light impurity
Data Source
AI summary
Lanthanide compounds for vapor deposition having ≤50.0 ppm, ≤30.0 ppm, or ≤10.0 ppm of all halide impurity combined is provided. The purification systems and methods are also provided.