Gas Phase Nucleation Detection Using Machine Vision

LAM<sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">®</sup> Altus Tungsten chemical vapor deposition (WCVD) process needs to monitor gas phase nucleation (GPN) as one of process control parameters. Main factor causing GPN is the increased in silane (SiH<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">4</inf>) flow (relative to WF<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">6</inf> flow), which create W<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">x</inf>Si<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">y</inf> particles. The GPN, which occurs during production, will lead to tungsten void due to SiH4 burst in nucleation step. However, control for such critical parameters is still manually done by visual inspection on a weekly basis. Hence, the auto GPN detection has been implemented using image recognition that is able to reduce human error and misjudgment, which in turn prevent wafer scraps incidents.