Page 371 - Sami Franssila Introduction to Microfabrication

350 Introduction to Microfabrication

Systematic Product
defects issues
Downtime
Transistor
functionality Manufacturing
Resistances Operational Cycle practices
window
Shorts Process time
Junction Feature
leakage CpK
Opens Size
Step Complexity Die
coverage Design
Al Hillocks Layout
Die yield
Process loss
interactions Ambient
Extra Environment Complexity
material Etch Clean Substrate
Wafer Corrosion room Process
edge Missing Liquids People
Machine material Cleans
Cleans Parameters
Pattern Chemicals Lithography
Pin holes Gases
Equipment
Vacuum
systems Cleans
Random Particles
defects
Figure 36.1 Factors influencing die-yield loss. Reproduced from Rao, G.P. (1993), by permission of McGraw-Hill

1.0
0.9
0.8
0.7
0.6
0.5
0.4
0.3

0.2
Yield

0.1 Poisson model
0.09 D 0 = 7 defects/cm 2
0.08
0.07
0.06
0.05
0.04

0.03
0 0.1 0.2 0.3 0.4 0.5
2
Chip area (cm )
Figure 36.2 Poisson distribution of chip yield: good fit for small chips. Reproduced from Cunningham, J.A. (1990), by
permission of IEEE