ForumCategory: VLSIAdvanced Layout Design Challenges at 7nm and Below
AvatarVLSI Master asked 2 weeks ago
I believe the aggressive scaling of layout design rules for 7nm technology without EUV has pushed the boundaries of what's technically possible. While it allows us to continue shrinking chip sizes, it introduces significant variability in yield and performance. The process windows have become so tight that even minor variations can lead to critical reliability issues like soft shorts or leakages, especially in FEOL and BEOL layers.
3 Answers
AvatarDigitalWorld answered 5 days ago

From my perspective, the main challenge is maintaining high yields in high-volume manufacturing. As the design rules scale down, systematic and parametric variations become more pronounced. The increased defectivity and edge placement errors make it difficult to ensure consistent performance across all chips. New techniques like Design-For-Inspection (DFI) are important to detect these subtle defects early in the process.

(Image source)

Avatarsemiconductor answered 5 days ago

Without EUV in the first 7nm nodes, I have to use multiple patterning techniques. These techniques are complicated and can cause problems, like more edge placement errors and smaller process windows. Even though EUV helps later, it brings its own issues like shot noise and local edge roughness. So, getting reliable performance is still a big challenge.

AvatarCircuitDesigner answered 5 days ago

Aggressive scaling has definitely helped us maintain Moore's Law, but it comes with drawbacks. When you look at devices at 7nm and below, you see reliability issues due to tighter spacing and higher chances of defects. The distance between the gate and source/drain is now at critical levels, which creates potential reliability risks. To tackle these challenges and ensure acceptable yield and performance, you and I need innovative solutions like the Single Diffusion Break and new characterization techniques.