In-Line Process Control Solutions:
Wafer Edge Exclusion Zone Inspection
Problem:
The exclusion zone measurement is increasingly required in metal layer
deposition and the photolithography process to determine if wafer films
have been properly aligned for the creation of the edge exclusion region
and to make the most of wafer’s very expensive real estate.
Solution:
RST-based tools are helping manufacturers to determine with a great precision
if edge bead removal (EBR) process worked as intended.
The topside surface measurement is required exclusively in the
photolithography process, primarily to determine if wafers have been
properly aligned for the creation of the edge exclusion region.
This process also verifies that the EBR process worked as intended.
EBR metrology measures the distance from the edge of a wafer to
the edge of the metallic or resist film at multiple points on a wafer.
This distance typically varies from 0mm to 6mm from the wafer edge.
Edge Exclusion Zone Measurement Specifications
|
|
Film Ø Accuracy
|
± 0.025mm
|
|
Sensitivity
|
.010mm
|
|
Repeatability
|
1 - 5%
|
|
|
Wafer with W film over adhesion layer (With varying exclusion zone)
|
|
|
|
