Electrochemical adjustment of thin film Ti-Pd resistors

Conference · Thu Jan 01 00:00:00 EST 1987

OSTI ID:6719149

Sharp, D J; Norwood, D P

Thin multilayered films consisting of tantalum nitride (Ta/sub 2/N), titanium, palladium, and gold are used at Sandia to fabricate hybrid microcircuits. From these stock multilayered composites, various circuits can be selectively etched and patterned to provide conductors and two levels of resistor patterns. The tantalum nitride is used to form resistor structures having values ranging from about 20 to 50,000 ohms. In order to provide resistors having values of about 1 to 4 ohms, the palladium, with its underlying titanium and Ta/sub 2/N layers, is used; these were designated as Ti-Pd resistors. Low resistivity tuned strip lines, for example, have this need. Present HMC technology typically limits the fabrication precision of thin film resistors to accuracies of 20 or 30%. Laser trimming is typically used to adjust out-of-tolerance resistors, however, in the case of strip line resistor applications this introduces undesirable variations in the impedance. We have completed a study of the use of an electrochemical probe which can be used to selectively deposit gold or, alternatively, remove palladium from the surface of the palladium composite film resistors described above. This permits resistor adjustment to either higher or lower values and does not produce discontinuities which occur with laser trimming. The process is similar in its result to that observed in the electrochemical or anodic trimming of Ta/sub 2/N resistors and is used to achieve practical tolerances of about 5% in Ti-Pd resistors. Studies describing accelerated life aging, temperature coefficient of resistance changes, and final adjustment precision are discussed.

• Research Organization: Sandia National Labs., Albuquerque, NM (USA)
• DOE Contract Number: AC04-76DP00789
• OSTI ID: 6719149
• Report Number(s): SAND-87-0625C; CONF-870388-3; ON: DE87007392
• Resource Relation: Conference: 14. international conference on metallurgical coatings, San Diego, CA, USA, 23 Mar 1987; Other Information: Portions of this document are illegible in microfiche products
• Country of Publication: United States
• Language: English

Related Subjects

42 ENGINEERING
MICROELECTRONIC CIRCUITS
FABRICATION
RESISTORS
SURFACE TREATMENTS
COMPOSITE MATERIALS
ETCHING
GOLD
PALLADIUM
PLATING
STABILITY
TANTALUM NITRIDES
THIN FILMS
TITANIUM
DEPOSITION
ELECTRICAL EQUIPMENT
ELECTRONIC CIRCUITS
ELEMENTS
EQUIPMENT
FILMS
MATERIALS
METALS
NITRIDES
NITROGEN COMPOUNDS
PLATINUM METALS
PNICTIDES
REFRACTORY METAL COMPOUNDS
SURFACE COATING
SURFACE FINISHING
TANTALUM COMPOUNDS
TRANSITION ELEMENT COMPOUNDS
TRANSITION ELEMENTS
420800* - Engineering- Electronic Circuits & Devices- (-1989)