Real Time Process Monitoring

The Lightwind L3 is a unique patented sensor system for detecting and analyzing the chemical conditions in various process tools in Etch, CVD and ALD.

Chemical detection is based on optical spectroscopy. The Lightwind L3 is independent from the process chamber and is typically installed in the foreline downstream of the chamber. In this way, the Lightwind L3 is non-invasive.

Functional block diagram of the L3 sensor. The unit is installed close to the process chamber and features its own plasma source. Optical emission is routed via optical fiber to a high-resolution CCD based spectrometer. The spectrometer output is processed by the Lightwind L3's computer for graphic display of the data, analysis, data storage, and transfer of analysis results to the fab network

In a small sensor head the Lightwind L3 generates an independent plasma with an ICP source powered at 13.56 MHz. Applied power level is typically less than 40 watts.

The independence from the process chamber's RF enables the Lightwind L3 to analyze reactor gas composition before the process chamber RF power is turned on. Additionally, the Lightwind L3 can re-ionize process gas effluents after they have left the main chamber, thereby increasing spectral sensitivity of the system.

Optical data from the Lightwind L3 source is routed via optical fiber to a high-resolution CCD based spectrometer. The spectrometer output is then processed by the Lightwind L3's computer for graphic display of the data, analysis, and data storage.

Typical applications of the Lightwind L3 include:

Endpoint for dry etch processes

Endpoint for in-situ chamber clean and condition steps

Detect and analyze chamber wall absorption and desorption

Detect helium blowby due to poor wafer clamping.

Characterize chamber condition after tool idle time and various PM activities.

Moisture and N₂ monitoring during reactor pumpdown to optimize wet clean recovery time

Detect by chemical signature many tool hardware process control problems, including incorrect gases, unstable pressure and flow, and unstable high speed switching valves in Atomic Layer Deposition processes

Detection of residual photo resist

Fault monitoring and automatic fault notification

Since the Lightwind L3 is installed remotely, but still very close to the process chamber, it detects problems in real time. The entire set-up is non-invasive to the process itself and therefore very well suited to precisely characterize existing process and equipment variations.

The Lightwind L3 features "always-on" functionality, providing a full time monitoring capability independent of process chamber plasma status.

The Lightwind L3 demonstrates value for chamber qualification, chamber matching and process transfer, and troubleshooting. Furthermore, the Lightwind L3 is now used by customers worldwide for process baselining, and integration into fab-wide APC and fault detection software. In these fabs, the Lightwind L3 detects and prevents wafer mis-processing and thus offers tremendous return on investment.

Lightwind Corporation was founded in 2001. The products are now in use in full wafer production and monitoring by fabs worldwide. Addtional information are available at Lightwind's web site