Dummy Feature Placement for Chemical- mechanical Polishing Uniformity in a Shallow Trench Isolation Process Ruiqi Tian 1,2 , Xiaoping Tang 1 , D. F. Wong 1 1. Dept. of CS, University of Texas at Austin, Austin, TX 78712 2. Motorola Inc., 3501 Ed Bluestein Blvd., Austin, TX 78721 {ruiqi, tang, wong}@cs.utexas.edu
Dummy Feature Placement for Chemical-mechanical Polishing Uniformity in a Shallow Trench Isolation Process. Ruiqi Tian 1,2 , Xiaoping Tang 1 , D. F. Wong 1. 1. Dept. of CS, University of Texas at Austin, Austin, TX 78712 2. Motorola Inc., 3501 Ed Bluestein Blvd., Austin, TX 78721 - PowerPoint PPT Presentation
Welcome message from author
This document is posted to help you gain knowledge. Please leave a comment to let me know what you think about it! Share it to your friends and learn new things together.
Transcript
Dummy Feature Placement for Chemical-mechanical Polishing Uniformity in a Shallow Trench Isolation Process
Ruiqi Tian1,2, Xiaoping Tang1, D. F. Wong1
1. Dept. of CS, University of Texas at Austin, Austin, TX 787122. Motorola Inc., 3501 Ed Bluestein Blvd., Austin, TX 78721
{ruiqi, tang, wong}@cs.utexas.edu
Outline
The STI Process Derivations for CMP in STI
Models used (a review) Assumptions and results
Dummy Feature Placement Problem formulation Iterative Approach
Computational Experience Conclusion
Nitride Deposition
The STI Process
Etch
Oxide Deposition
Nitride Strip
CMP
CMP in STI is a dual-material polish
Models: Effective Density from Pad Bending
Derivations for CMP in STI
Li
Lii
Lj
Ljj
jjiifjidji' '
)','()','(),(
Models: Local Pad Compression
Derivations for CMP in STI
Polish rates of high and low areas are related by step height due to pressure re-distribution
Initial contact height decreases with increasing density, no consideration for spacing
Models: Dual-Material Polish
Derivations for CMP in STI
Polish rates are similar to local pad compression Different blanket polish rate for different materials Intersection depends on contact height and density
Assumptions:
Derivations for CMP in STI
Two stages identified for CMP in STI Overburden oxide removal Dual-material polish of nitride and oxide