title = "Wafer Topography and Planarization"

content = """
The topography of the wafer surface can significantly impact the 
lithography process, especially as feature sizes shrink and the 
Depth of Focus (DoF) becomes smaller.

**CMP (Chemical Mechanical Planarization):**
CMP is a process step used to flatten the wafer surface after 
deposition or etching. It uses a combination of chemical etching 
and mechanical polishing to remove excess material and create a 
planar surface. A flat surface is essential for maintaining 
focus across the entire wafer during lithography.

**Focus Spots and Topography:**
Even with CMP, small variations in wafer topography can cause 
localized focus errors, known as "focus spots." These can be 
caused by underlying circuit features, particles on the back of 
the wafer, or non-uniformities in the CMP process.

**Leveling and Autofocus:**
Scanners use high-precision sensors to map the wafer's topography 
in real-time during exposure and adjust the focus accordingly. 
However, if the topography variations are too large or too 
abrupt, the scanner's autofocus system may not be able to 
compensate, leading to pattern failure.

**Edge Bead Removal (EBR):**
During spin-coating, photoresist can build up at the edge of the 
wafer, creating a thick "edge bead." This bead can cause focus 
errors and contamination. EBR is a process step that removes 
this excess resist using a solvent or a laser.
"""

version = "0.0.1"
