1. LAYOUT DESIGN RULES Bellary Engg College,Bellary, karnatakaBY
Mr. MANU T.M
Bellary Engg College,Bellary,
karnataka

2. Objectives: Outcomes:
Understand the need of design rules in fabrication process.
Different type of design rules and advantages.
Dimensions of different layers and separation in terms of lambda rules.
Outcomes:
We will understand the different types rules, the dimensions of each layers and advantages of different rules.

3. DESIGN RULES
The physical layout of any ckt to be manufactured using particular process must conform to set of geometric constraints or rules. Which are generally called as layout design rules.
These rules usually specifies the minimum allowable line widths for physical objects on chips, such as metal, poly, diffusion etc.,

4. Why we need design rules
Masks are tooling for manufacturing.
Interface between designer and process engineer.
Manufacturing processes have inherent limitations in accuracy.
Design rules specify geometry of masks which will provide reasonable yields.
Design rules are determined by experience.

5. Types of Design Rules Scalable Design Rules Absolute Design Rules
Idea: reduce l value for each new process, but keep rules the same
Key advantage: portable layout
Key disadvantage: not everything scales the same
Absolute Design Rules
Based on absolute distances (e.g. 0.75µm)
Tuned to a specific process
Complex, especially for deep submicron
Layouts not portable

6. Design Rule Summary Line size and spacing:
metal1: Minimum width=3l, Minimum Spacing=3l
metal2: Minimum width=3l, Minimum Spacing=4l
poly: Minimum width= 2l, Minimum Spacing=2l
ndiff/pdiff: Minimum width= 3l, Minimum Spacing=3l, minimum ndiff/pdiff seperation=10l
wells: minimum width=10l, min distance form well edge to source/drain=5l
Transistors:
Min width=3l
Min length=2l
Min poly overhang=2l

11. Questions ?
Thank you