Thin film chip resistors with high resistance and low temperature coefficient of resistance

Abstract

High resistance thin film chip resistors (0603 type) were studied, and the specifications are as follows: 1 kΩ with tolerance about ±0.1% after laser trimming and temperature coefficient of resistance (TCR) less than ±15×10⁻⁶/°C. Cr-Si-Ta-Al films were prepared with Ar flow rate and sputtering power fixed at 20 standard-state cubic centimeter per minute (sccm) and 100 W, respectively. The experiment shows that the electrical properties of Cr-Si-Ta-Al deposition films can meet the specification requirements of 0603 type thin film chip resistors when the deposition time was about 11 min and deposition films were annealed at 500 °C for 120 min. The morphologies of Cr-Si-Ta-Al film surfaces were examined by scanning electron microscopy (SEM). The analysis suggests that Ta and Al may be distributed in CrSi₂ film with mixed form of several structures (e.g., bridge-like, capillary-like or island-like structures), and such a structure distribution is responsible for high film resistance and low TCR of Cr-Si-Ta-Al film.

Keywords

thin film chip resistor / high resistance / low temperature coefficient of resistance / alloy target / magnetic sputtering / Cr-Si-Ta-Al film

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