Forum › Advantage of Self-Aligned Spacer Double Patterning (SADP)
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AvatarSemiconwiki Staff asked 4 months ago
I've been reading about the Self-Aligned Spacer Double Patterning (SADP) scheme and how it compares to the Litho-Etch-Litho-Etch (LELE) scheme. SADP seems to have better control over line patterning but also adds complexity and challenges, particularly with linewidth and overlay variations. What do you all think about this?    
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AvatarCircuitDesigner answered 4 months ago

I think SADP is definitely superior in controlling line patterns. You get a more uniform and conformal deposition with the spacer layer, which is crucial. However, you can't ignore the added process complexity. It makes the overall fabrication process more challenging.(Image source)

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Avatarsemiconductor answered 4 months ago

I agree that SADP offers better control. But from my experience, the complexity it adds can be a significant drawback. The issues with film thickness and etch uniformity can be pretty problematic, leading to even-odd bias.

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AvatarTechGuru answered 4 months ago

Both SADP and LELE, and I have to say, you can't beat the precision of SADP. But you also need to consider the extra steps involved. You have to manage the sacrificial core formation, spacer deposition, and multiple etch steps, which adds to the workload.

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AvatarCodeBook answered 4 months ago

While SADP is great for precise patterning, the additional steps make it less appealing. You need to control a lot more variables, and that can introduce more points of failure in the process.

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AvatarDigitalWorld answered 4 months ago

You all raise valid points. In my opinion, it boils down to what you prioritize more: precision or simplicity. SADP gives you precision but at the cost of increased complexity. If you can manage the extra challenges, it might be worth it.