Substrate Pressure Cycling for Thin-Film Impurity Removal
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Solution Overview
Problem
Existing substrate processing methods struggle to effectively remove impurities from inside thin films without degrading film characteristics, particularly in three-dimensional devices with high aspect ratios and high impurity contents, leading to issues like changed threshold voltage, widened capacitance distribution, and degraded voltage-resistance characteristics.
Innovation Solution
A processing method involving pressure changes within a chamber, including pressurizing to a first pressure greater than atmospheric pressure, followed by sequential depressurizing steps to remove impurities, forming byproducts, and discharging them, followed by thin film formation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Shape
If deposition temperature is lowered or sources with higher impurity contents are used to satisfy step coverage standard, then step coverage is improved, but impurity removal becomes more difficult
Solution Approach 1:
The patent applies preliminary action by performing pressure change processing before thin film formation to remove impurities from the substrate surface. This preliminary impurity removal ensures that subsequent film deposition occurs on a clean surface, preventing impurity incorporation even when using lower deposition temperatures or higher impurity content sources required for good step coverage.
Solution Approach 2:
The patent utilizes parameter changes by varying pressure conditions during processing. The pressure change processing involves transitioning between different pressure states to remove impurities, while deposition is performed at controlled pressures. This parameter variation enables impurity removal without compromising the deposition conditions needed for adequate step coverage.
2Reliability
If pressure change processing is performed to remove impurities, then impurity removal is improved, but processing time increases
Solution Approach 1:
The patent applies periodic action through cyclic pressure changes during the processing sequence. The pressure change processing involves repeated transitions between pressure states, creating periodic cycles that efficiently remove impurities through pressure-driven mechanisms. This periodic approach achieves thorough impurity removal while controlling the total processing duration through optimized cycle timing.
3Reliability
If multiple pressure change cycles are performed to thoroughly remove impurities, then impurity removal is improved, but processing complexity increases
Solution Approach 1:
The patent applies segmentation by dividing the pressure change processing into multiple distinct cycles, each with specific pressure transition patterns. This segmented approach allows systematic impurity removal through repeated application of pressure changes, with each cycle targeting residual impurities from previous cycles. The segmented structure makes the complex multi-cycle process manageable and controllable.
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 enhances thin film characteristics by removing impurities, improving resistivity and voltage resistance, and promoting recrystallization, thereby increasing the reliability and performance of semiconductor devices.
Implementation Method 1
a processing method involving pressure changes within a chamber, including pressurizing to a first pressure greater than atmospheric pressure, followed by sequential depressurizing steps to remove impurities, forming byproducts, and discharging them
Data Source
AI summary
The present invention relates to a substrate processing method, and more particularly, to a processing method for substrate for removing impurities from inside a thin film of a substrate and improving characteristics of the thin film.