Gap Filling Deposition for Void-Free Trench Isolation
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Solution Overview
Problem
Void formation during trench fill in integrated circuit manufacturing compromises device isolation and structural integrity, limiting device packing density and affecting field threshold voltage.
Innovation Solution
A method involving the sequential introduction of reactants with controlled doses to form monolayers, where a subsaturating first reactant covers the gap's top, a saturating second reactant covers the bottom, and a third reactant reacts with the first and second to fill the gap from the bottom upwards, using a semiconductor processing apparatus with controlled gas valves and reactant sources.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional trench filling is used, then the trenches are filled to provide device isolation, but voids form during refilling that compromise device isolation and structural integrity
Solution Approach 1:
The trench filling process is segmented into multiple sequential deposition steps using different reactants. The first reactant deposits a initial layer, followed by a second reactant that fills remaining gaps, and finally a third reactant completes the filling. This segmentation allows each reactant to target specific areas, ensuring complete filling without void formation while maintaining reliable device isolation.
Solution Approach 2:
The first reactant is introduced with a subsaturating dose to perform preliminary deposition in the top area of the trench before the second reactant is introduced. This preliminary action prepares the surface and ensures that subsequent reactants can reach and fill the bottom areas effectively, preventing void formation while maintaining isolation effectiveness.
2Manufacturing precision
If trench depth is decreased to mitigate void formation, then voids are reduced, but the effectiveness of device isolation is reduced
Solution Approach 1:
The invention changes the parameters of the deposition process by using sequential reactant introduction with controlled doses. Instead of reducing trench depth, the process parameters (reactant dosage, introduction sequence) are modified to ensure complete filling of the full trench depth, maintaining isolation effectiveness while eliminating voids through precise parameter control.
3Manufacturing precision
If trench openings are made larger at the top to prevent voids, then void formation is reduced, but additional integrated circuit real estate is used
Solution Approach 1:
The invention applies local quality by directing different reactants to different areas of the trench. The first reactant with subsaturating dose targets the top area, while subsequent reactants fill the bottom and middle sections. This localized approach ensures complete filling without requiring larger opening areas, maintaining high device packing density while preventing voids.
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 prevents void formation, enhances device isolation, and improves device packing density by ensuring complete gap filling without structural compromise.
Implementation Method 1
introducing a first reactant to the substrate with a first dose, thereby forming no more than about one monolayer by the first reactant
Implementation Method 2
introducing a third reactant to the substrate with a third dose to react with at least one of the first and second reactant
Data Source
AI summary
According to the invention there is provided a method of filling one or more gaps created during manufacturing of a feature on a substrate by providing a deposition method comprising; introducing a first reactant to the substrate with a first dose, thereby forming no more than about one monolayer by the first reactant; introducing a second reactant to the substrate with a second dose. The first reactant is introduced with a sub saturating first dose reaching only a top area of the surface of the one or more gaps and the second reactant is introduced with a saturating second dose reaching a bottom area of the surface of the one or more gaps. A third reactant may be provided to the substrate in the reaction chamber with a third dose, the third reactant reacting with at least one of the first and second reactant.