IN-SITU PROCESS MONITORING

Our team has been at the forefront of in-situ process monitoring in various ion beam and thin-film processes. We are highly experienced in the integration of these systems for the automatic control of process gas mixing, etch endpoint control, and deposition endpoint control.

Our experience with integration of in-situ optical monitoring in ion beam systems includes:
Optical instrumentation systems based on optical interference: As the North American agent for Intellemetrics, 4Wave has integrated a reflective optical monitoring system used for laser bar facet coatings.

Etch endpointing by secondary ion mass spectrometry (SIMS): 4Wave employees integrated the first SIMS units into production IBE systems. The SIMS units monitor the composition of the flux sputtered from the etching film. This technique can be used to reliably endpoint an etch terminating at or near the interface of almost any two dissimilar materials, with better than 2 angstrom accuracy (in an open area of only 2 percent). Multi-step, multi-interface endpointing is also possible. This is an extremely reliable, sensitive and versatile endpointing technology.

Etch endpointing by optical emission spectroscopy (OES): 4Wave employees have integrated optical emission spectrometers into IBE systems. These systems measure the optical spectrum of the photons emitted at the etching film surface. Materials of different composition have correspondingly different spectra. Hence, this technique can be used to reliably endpoint at the interfaces of many dissimilar materials.

Partial pressure control by residual gas analysis (RGA): 4Wave employees have implemented partial pressure control in reactive deposition and etch systems by actively monitoring partial pressure with an RGA and controlling the gas flows into the chamber to meet established target partial pressures.

Deposition thickness monitoring by quartz crystal oscillators: 4Wave employees have extensive experience in the use of quartz crystal oscillators to monitor and control deposition thickness. Plasma process analysis by electric probes: 4Wave employees have designed and implemented numerous systems that involve active monitoring and control of ion currents, electron currents and plasma potentials.