Cavity Fill via Angled Ion Sputtering
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing electronic device processing techniques, such as chemical vapor deposition, face challenges in filling small structures like trenches or vias with high aspect ratios, often resulting in overhangs and the formation of seams or buried holes due to non-conformal coating.
Innovation Solution
A method involving the use of a combination of neutral reactive precursor species and directed energetic ions, where the ions are angled to strike the sidewall portions of the cavity at a non-zero angle, promoting a bottom-up fill process by redistributing the fill material from the sidewall to the lower surface, avoiding overhangs and seams.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If chemical vapor deposition is used to fill cavities, then coating occurs on exposed surfaces, but overhangs form leading to seams or buried holes in high aspect ratio trenches
Solution Approach 1:
The patent applies asymmetry by directing ions at a non-zero angle of incidence relative to the substrate normal. This asymmetric ion bombardment preferentially removes material from upper cavity regions while allowing deposition to occur at lower regions, creating a bottom-up fill pattern that prevents overhangs and seams. The angled ion flux breaks the symmetry of conventional conformal deposition, enabling selective material redistribution.
Solution Approach 2:
The patent inverts the conventional deposition approach by using ion bombardment to preferentially remove material from regions that would normally accumulate material (the upper cavity regions). This inverse approach, where erosion occurs where deposition would normally dominate, prevents overhang formation and enables seamless cavity filling from the bottom up rather than top down.
2Quantity of substance
If conformal coating is applied to high aspect ratio cavities, then coating covers all exposed surfaces, but material accumulates on sidewalls forming overhangs
Solution Approach 1:
The patent applies local quality by creating spatially non-uniform material distribution through angled ion bombardment. The ion flux is directed at a non-zero angle, causing preferential material removal from specific regions (upper cavity and sidewall portions) while preserving or enhancing deposition in other regions (lower cavity). This local differentiation of material removal and deposition rates prevents uniform overhang formation and enables controlled bottom-up filling.
Solution Approach 2:
The patent changes the ion incidence angle parameter from zero (normal incidence) to a non-zero angle. This parameter change fundamentally alters the material transport dynamics, causing ions to strike the substrate at an angle that preferentially affects upper cavity regions. The modified incidence angle parameter enables selective sputtering that redistributes material vertically, preventing horizontal overhang accumulation.
3Manufacturing precision
If angled ions are directed at the cavity, then material is removed from sidewalls, but the cavity must be filled simultaneously
Solution Approach 1:
The patent converts the harmful effect of ion bombardment (material removal) into a beneficial process. The angled ion flux, which would normally be considered erosive and wasteful, is instead used to selectively remove material from upper cavity regions where it would form defects. The sputtered material is redistributed and redeposited in lower cavity regions, transforming material loss into a controlled redistribution mechanism that enables seamless filling.
Solution Approach 2:
The patent uses angled ion bombardment as an intermediary mechanism to mediate between deposition and final cavity fill quality. The ions act as a mediating agent that redistributes deposited material, transferring it from upper regions where it would form overhangs to lower regions where it contributes to seamless filling. This intermediary process couples deposition and erosion into a unified bottom-up fill mechanism.
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 ensures a seamless fill of cavities by preferentially depositing material in lower regions, preventing the formation of seams or buried holes, and efficiently filling high-aspect-ratio features without overhangs.
Implementation Method 1
a plasma generator coupled to the plasma chamber and generating a plasma comprising sputtering gas derived from the sputtering gas flow and a reactive species derived from the reactive precursor gas flow
Implementation Method 2
the reactive species generating a fill material at the substrate
Implementation Method 3
an angled ion beam is directed to the substrate through the extraction plate, the angled ion beam comprising angled ions incident at a surface of the substrate at a non-zero angle of incidence
Data Source
AI summary
A method may include providing a cavity in a surface of a substrate, the cavity comprising a sidewall portion and a lower surface; directing depositing species to the surface of the substrate, wherein the depositing species condense to form a fill material on the sidewall portion and lower surface; and directing angled ions at the cavity at a non-zero angle of incidence with respect to a perpendicular to a plane defined by the substrate, wherein the angled ions strike an exposed part of the sidewall portion and do not strike the lower surface, and wherein the cavity is filled by the fill material in a bottom-up fill process.