Rapid thermal annealing (RTA) means using a controlled, relatively short heating cycle to change a wafer's material state. It names a thermal operation, not a guaranteed result. The question to ask is what the incoming wafer needs, what temperature history it actually experiences, and which property changes afterward. For implanted silicon, electrical activation, damage recovery, and dopant redistribution are related but separately measured outcomes.
What is being annealed?
An implanted region may contain inactive dopants and lattice damage. Heating can change both, and can also move dopants. State the starting material and intended endpoint before treating “RTA” as evidence of a result. The activation and diffusion article explains the separate measurements .
Process map
40nm BSI CMOS Image Sensor
In the public 40nm Flow overview, locate PolySi Anneal under Gate and Dopants Activation in the later Well group; these labels locate thermal duties without verifying RTA heating or results.
A nominal cycle is not the whole wafer history
A nominal heating schedule is only a description of the intended treatment. Actual wafer temperature may vary with pattern and surface optical properties, so the thermal result should be checked through the treated material rather than inferred from the equipment label .
The relevant history includes heating, the hot interval and cooling. Different starting structures can produce different results even under the same RTA label. Report the intended change together with an appropriate before-and-after measurement .
Test the claimed result separately
Electrical measurements can assess whether implanted dopants contribute carriers; a concentration profile can reveal redistribution. Those are separate questions, and neither result should be inferred solely from the word annealing .
Find the relevant duties in a Flow
In the public 40nm BSI CMOS Image Sensor Flow overview, expand Gate to locate PolySi Anneal and the later Well group to locate Dopants Activation after Source/Drain. The labels identify two places where a thermal question belongs in the integration sequence. They do not say that either Step uses RTA, nor do they disclose a measured wafer temperature or activation result. Use the overview to locate the context, then seek the specific evidence before drawing a process conclusion.
References
Silicon VLSI Technology - Full
James D. Plummer, Michael D. Deal, Peter B. Griffin
Silicon VLSI Technology · ISBN 978-0130850379