(Invited) Spatial ALD Challenges and Opportunities in Advanced Integrated Circuit Manufacturing

Abstract

Miniaturization in Integrated Circuit fabrication has scaled to atomic dimensions in recent times. With critical device dimensions moving into the range of ~10nm, atomic layer processing control is becoming essential. Atomic Layer Deposition (ALD) uses separated film components at (or near) self-limiting conditions for atomic level uniformity and thickness control. The unique nature of ALD processing has opened the opportunity for a deposition technique that presents deposition components in a spatially separated method compared to sequential component exposure of traditional systems. Spatial ALD has differentiating characteristics that can benefit IC Fabrication at current fabrication dimensions. Historically, deposition systems for IC fabrication use batch furnace or single wafer configurations. The economic benefit of batch furnace processing has been challenged by the enhanced capabilities of single wafer processing as IC scaling emphasized critical film properties and uniformity. ALD processing has rejuvenated batch furnace benefits since separate exposures of deposition components provides excellent uniformity from self-limiting deposition layers, and lower particle defectivity since the components don’t mix. However, the sequential processing of individual components has strained the efficiencies of batch furnace and single wafer ALD processing. Spatial ALD moves substrates (wafers) through each deposition component separately in space, compared to the time sequential processing of batch furnaces and single wafer processing. There are several advantages to Spatial ALD processing, and several unique capabilities that can apply to IC fabrication. By depositing through movement, the deposition components can be maintained through a steady state, which is advantageous for plasma processing and for limiting peripheral equipment film accumulation. By its nature, the deposition rate of Spatial ALD is controlled by the speed of substrates passing through the deposition zones, which can provide unique controls for deposition. Deposition chemistry and process conditions can be designed to take advantage of Spatial ALD properties for unique benefits in IC fabrication. The presentation will explore some fundamental aspects of Spatial ALD processing, the dependency and opportunities of relevant chemistries, and potential applications for the unique capabilities of Spatial ALD, including unsaturated process conditions.