Etch characteristics of giant magnetoresistive materials

• Published in: Microelectronic engineering Vol. 53; no. 1; pp. 367 - 370
• Main Authors: Resnick, D.J., Pendharkar, S., Kyler, K., Kerszykowski, G., Clemens, S., Tompkins, H., Durlam, M., Tehrani, S.
• Format: Journal Article Conference Proceeding
• Language: English
• Published: Amsterdam Elsevier B.V 01.06.2000; Elsevier Science
• Subjects: Applied sciences; Condensed matter: electronic structure, electrical, magnetic, and optical properties; Design. Technologies. Operation analysis. Testing; Electronics; Exact sciences and technology; Giant magnetoresistance; Integrated circuits; Lithography, masks and pattern transfer; Magnetic properties and materials; Magnetotransport phenomena, materials for magnetotransport; Microelectronic fabrication (materials and surfaces technology); Microelectronics: LSI, VLSI, ULSI; integrated circuit fabrication technology; Physics; Physics of gases, plasmas and electric discharges; Physics of plasmas and electric discharges; Plasma applications; Semiconductor electronics. Microelectronics. Optoelectronics. Solid state devices; Interfacial layer; Probabilistic approach; Oxide layer; High density; Machining; Giant magnetoresistance; Autoregressive model; Regression analysis; Chemical etching; Experimental study; Thin film; Plasma application; Random access memory(RAM); Corrosion; Non volatile memory; Wear; Milling; Endurance; Memory effect
• ISSN: 0167-9317; 1873-5568
• DOI: 10.1016/S0167-9317(00)00335-X

The continued growth in communications has increased the need for non-volatile memories. One particular approach is magnetoresistive random access memory (MRAM). Because there is no wear-out mechanism, read/write endurance is virtually unlimited, making the technology attractive for a variety of different memory applications. Historically, reactive etching of magnetic thin films has proven to be difficult and ion milling is typically used to pattern the GMR layer. In this work, a high density Cl 2/Ar plasma is used to etch the GMR film stack. Redeposition effects were eliminated, with no serious effect on the underlying oxide layer. Acceptable GMR ratios were obtained for larger bit features, however the ratio drops significantly as bit size decreases. The decrease appears to be a result of corrosion in the copper interlayer of the GMR film stack.