Silicon Nitride Gap Filling for Void-Free High-Aspect Trenches
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Solution Overview
Problem
The miniaturization of semiconductor devices has led to challenges in void-free filling of high aspect ratio trenches due to limitations in existing deposition processes, necessitating efficient methods for filling gaps in semiconductor substrates.
Innovation Solution
A method involving the introduction of a substrate with a gap into a process system, where a precursor comprising silicon, nitrogen, and hydrogen is exposed to a plasma, and the resulting gap filling fluid with a Si—N bond is cured using vacuum ultraviolet radiation and ambient gases like nitrogen and hydrogen-containing gases, enabling the formation of silicon nitride without voids.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If conventional deposition processes are used for miniaturized semiconductor devices, then device scaling is achieved, but void-free filling of high aspect ratio trenches becomes difficult
Solution Approach 1:
The patent changes the physical and chemical parameters of the deposition process by introducing a cyclic sequence of precursor exposure, plasma treatment, and curing steps. This transforms the conventional continuous deposition into a controlled cyclic process with varying parameters (temperature, pressure, gas composition) at each stage, enabling complete gap filling in high aspect ratio trenches without voids
Solution Approach 2:
The patent implements periodic action through cyclic deposition processes where the substrate undergoes repeated sequences of precursor introduction, plasma activation, and thermal/curing treatment. This periodic cycling allows gradual buildup of gap-filling material while maintaining process control, solving the void-free filling problem in miniaturized devices
2Quantity of substance
If gap filling fluid is deposited in high aspect ratio trenches, then gap filling is achieved, but void formation occurs
Solution Approach 1:
The patent ensures continuity of useful action by maintaining the gap-filling process through cyclic repetition of deposition and curing steps. The continuous cycling allows material to be progressively deposited and cured in layers, ensuring complete penetration into high aspect ratio trenches without forming voids, while continuously building up the required quantity of gap-filling material
3Reliability
If plasma treatment is applied to activate precursor, then gap filling fluid formation is improved, but process complexity increases
Solution Approach 1:
The patent introduces plasma as an intermediary medium between the precursor molecules and the final gap-filling material. The plasma treatment activates the precursor to form reactive species that can polymerize into the desired gap-filling material. This intermediary step improves reliability of gap filling fluid formation while the cyclic structure organizes the complexity into manageable repeating units
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 effectively fills gaps with silicon nitride, reducing void formation and improving the wet etch rate ratio and film properties, such as refractive index and thickness, while maintaining low carbon content and shrinkage upon annealing.
Implementation Method 1
generating a plasma. The plasma causes the precursor and the reactant to react to form a gap filling fluid
Implementation Method 2
exposing the substrate to vacuum ultraviolet radiation and to an ambient gas. Thus, the gap filling fluid is cured
Data Source
AI summary
Methods and related systems for at least partially filling recesses comprised in a substrate with a gap filling fluid. The gap filling fluid comprises a Si—N bond. The methods comprise exposing the substrate to a nitrogen and hydrogen-containing gas on the one hand and to vacuum ultraviolet light on the other hand.