Area-Selective Thin Film Deposition for DRAM Leakage Control
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Solution Overview
Problem
In the miniaturization of DRAM devices, there is a challenge in maintaining high capacitance and low leakage current while preventing the deposition of dielectric films in unintended areas, leading to unwanted leakage currents.
Innovation Solution
An area-selective thin film formation method using a selectivity material that adsorbs to non-growth regions, preventing precursor adsorption and reaction in those areas, while allowing deposition on growth regions, utilizing Metal Organic Chemical Vapor Deposition (MOCVD) or atomic layer deposition (ALD) processes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a seed layer is deposited to help crystallize the dielectric layer, then a crystal structure having a high dielectric constant can be formed at relatively low temperature, but the seed layer is deposited even where a dielectric film should not be deposited, resulting in leakage current
Solution Approach 1:
The patent applies preliminary action by introducing a selectivity material before the seed layer deposition to pre-modify the substrate surface. This selectivity material is deposited first and selectively removed from certain regions, creating a patterned surface that guides subsequent selective deposition. The preliminary modification of the substrate surface enables controlled seed layer formation only in desired areas, preventing leakage current while maintaining low-temperature crystallization benefits
Solution Approach 2:
The patent implements local quality by creating regions with different surface properties through selective deposition or removal of the selectivity material. Different areas of the substrate are given distinct characteristics - some regions become receptive to seed layer deposition while others remain resistant. This local differentiation allows the seed layer to form crystal structures with high dielectric constant only where needed, while avoiding deposition in regions where it would cause leakage current
2Productivity
If the capacitor size is reduced to improve miniaturization, then device density increases, but maintaining high capacitance and low leakage current becomes difficult
Solution Approach 1:
The patent applies local quality by creating spatially differentiated regions on the capacitor structure. The selectivity material creates distinct zones with different properties - some areas optimized for high capacitance through controlled dielectric layer formation, while other areas are engineered to minimize leakage current. This local optimization allows the miniaturized capacitor to maintain both high capacitance and low leakage current despite reduced overall size
Solution Approach 2:
The patent implements segmentation by dividing the capacitor structure into functionally distinct regions through selective deposition patterns. The dielectric layer, seed layer, and selectivity material create segmented zones that independently contribute to capacitance or leakage prevention. This segmentation allows the miniaturized device to optimize different functional aspects in different areas, maintaining reliability while increasing device density
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 method effectively minimizes leakage current by ensuring selective deposition of thin films only on desired areas, enhancing capacitance and reducing unwanted film thickness, thereby improving the reliability and performance of DRAM devices.
Implementation Method 1
supplying the selectivity material to the inside of the chamber in which the substrate is placed, so that the selectivity material is adsorbed to a non-growth region of the substrate
Implementation Method 2
supplying a precursor to the inside of the chamber, so that the precursor is adsorbed to a growth region of the substrate
Implementation Method 3
supplying a reaction material to the inside of the chamber, so that the reaction material reacts with the adsorbed precursor to form the thin film
Implementation Method 4
the reaction material reacts with the adsorbed precursor to form the thin film
Data Source
AI summary
Disclosed is a method of forming an area-selective thin film, the method comprising supplying the selectivity material to the inside of the chamber in which the substrate is placed, so that the selectivity material is adsorbed to a non-growth region of the substrate; purging the interior of the chamber; supplying a precursor to the inside of the chamber, so that the precursor is adsorbed to a growth region of the substrate; purging the interior of the chamber; and supplying a reaction material to the inside of the chamber, so that the reaction material reacts with the adsorbed precursor to form the thin film.