1. Zero Skew Clock tree Implementation

2. Skew & Wirelength What is skew About zero skew
Definition : the max difference in arrival times of receivers.
About zero skew

3. Skew & Wirelength About wirelength
Problem: zero skew & minimize the wirelength

4. Clock tree A binary tree Root = source Leaves = sinks clock entry A BD E F G H

5. Problem: zero skew & minimize the wirelength
Topology generation
DME algorithm
point set
topology
Clock tree
output

6. DME algorithm DME ( deferred-merge embedding )
Given any topology (tree)  exact zero skew
Two Phase
Bottom-Up (build tree of merging segments)
Top-Down (embedding of nodes)

7. DME algorithm Example : Bottom-Up phase Top-Down phase D E C F A B C D
4.5 C 5 F A B C D E F G H
8.5 8 12 G 3 A H
3.5 B

8. Manhattan & X architecture

9. Topology generation How to match? Good topology  smaller wirelength.
Some method of topology generation
BB (Balanced Bipartition)
MMM (Method of Means and Medians)
NS (Nearest-neighbor Selection)

10. Topology generation For k sinks, it have different trees.
Complexity:
Good method  save time

11. Topology generation
About MMM

12. Topology generation
About my method : complexity:

13. Topology generation
Still have bugs
Under Elmore Delay Model

14. Result: Manhattan, My method
Sample: r1.pin
267 sinks

15. Result: Manhattan, MMM
Sample: r1.pin
267 sinks

16. Result: X ,my method
Sample: r1.pin
267 sinks

17. Result: X, MMM
Sample: r1.pin
267 sinks

18. R1.pin Result wirelength My method, Manhattan 1.59299e+006
My method, X
e+006
MMM, Manhattan
e+006
MMM, X
e+006 %
My method v.s. MMM,
Manhattan
-5.02% X
-2.53%
MMM, Manhattan
13.01%
MMM, X
10.9%

19. Future Work
wirelength

20. Future Work
Matching on X

21. Thank You