In-situ analysis of particle contamination in magnetron sputtering processes

• Published in: Thin solid films Vol. 317; no. 1; pp. 85 - 92
• Main Authors: Selwyn, Gary S, Weiss, Corey A, Sequeda, Federico, Huang, Carrie
• Format: Journal Article Conference Proceeding
• Language: English
• Published: Lausanne Elsevier B.V 01-04-1998; Elsevier Science
• Subjects: Chemical vapor deposition (including plasma-enhanced cvd, mocvd, etc.); Cross-disciplinary physics: materials science; rheology; Deposition by sputtering; Exact sciences and technology; Magnetron sputtering processes; Materials science; Methods of deposition of films and coatings; film growth and epitaxy; Particulate contamination; Physics; Thin film products; Thin film products; Magnetron sputtering processes; Particulate contamination; Thin films; Magnetrons; Plasma; In situ; Crystal growth from vapors; PECVD; Experimental study; Contamination; Particles; Sputtering
• ISSN: 0040-6090; 1879-2731
• DOI: 10.1016/S0040-6090(97)00603-2

Defects caused by particulate contamination are an important concern in the fabrication of thin film products. Often, magnetron sputtering processes are used for this purpose. Particle contamination can cause electrical shorting, pin holes, problems with photolithography, adhesion failure, as well as visual and cosmetic defects. Particle contamination generated during thin film processing can be detected using laser light scattering, a powerful diagnostic technique that provides real-time, in situ imaging of particles >0.3
μm in diameter. Using this technique, the causes, sources and influences on particles in plasma and non-plasma processes may be independently evaluated and corrected. Several studies employing laser light scattering have demonstrated both homogeneous and heterogeneous causes of particle contamination. In this paper, we demonstrate that the mechanisms for particle generation, transport and trapping during magnetron sputter deposition are different from the mechanisms reported in previously studied plasma etch processes. During magnetron sputter deposition, one source of particle contamination is linked to portions of the sputtering target surface exposed to weaker plasma density. In this region, film redeposition is followed by filament or nodule growth and enhanced trapping that increases filament growth. Eventually, the filaments effectively `short-circuit' the sheath, causing high currents to flow through these features. This, in turn, causes heating failure of the filament fracturing and ejecting the filaments into the plasma and onto the substrate. Evidence of this effect has been observed in semiconductor (IC) fabrication and storage disk manufacturing. Discovery of this mechanism in both technologies suggests that this mechanism may be universal to many sputtering processes.