Lightwind Wet Etch Endpoint Aep 2
The Lightwind Aep 2 is an add-on endpoint system for wet processing. Utilizing optical reflectance spectroscopy, automated endpoint detection is now an option for many wet processing applications.
The Aep 2 is specifically designed to improve wet etch process control, while offering a measurement that adjusts to concentration changes in the bath. With time resolution of 1 second for endpoint, normal process variation and undercut are reduced and become more reproducible. Etch for many different films can be controlled by endpoint (such as Ti/oxide, Cu/Ti) .
Benefits of endpoint control
Improved Process Control
- 1 second resolution on measured wafer
- endpoint is based on wafer clearing, so it automatically adjusts
to changes in bath concentrations and temperature
- undercut associated with overetch is reduced
- endpoint allows more tolerance to batch chemistry variations
Cost savings
- automated endpoint minimizes process time associated with
fixed time processes, allowing higher throughput
- increased throughput, or simply reduced process time reduces
chemical costs and disposal costs
- reduction in number of test wafers required
Non Invasive
- endpoint hardware can be mounted outside the bath or process
enclosure in most cases
System Specification
Sensor Head Typically very small, configured to be tool specific
Consists of a light source and light detector
Light source Vis -NIR Optimized for films of interest
Lifetime Projected 10,000 hours or 1/ year
Spectrometer Vis / NIR Multichannel multiple
active wavelengths Resolution ~ 2 microns
Sample rate: variable depends on light but can be
as little as 10 milliseconds
Software Lightwind endpoint and data logging software
includes endpoint simulator, strip chart recording
data logging for selected channels or full spectra.
Output for ethernet/factory link.
