Control of nichorme resistor temperature coefficient using RF plasma sputter etch

A method for processing a partially fabricated semiconductor wafer having a layer of nichrome resistor material patterned to form a plurality of resistors on a surface of the wafer, the method comprising:

• (a) performing a wet pre-metallization cleaning step on the surface of the wafer in a first reactor;
• (b) passing argon gas into the first reactor with the wafer therein and producing an argon plasma in the first reactor adjacent to the surface of the wafer by applying a power signal having a frequency of approximately 100 kHz to an inductive coil wound around a reaction chamber of the first reactor and the applying an RF signal having a voltage of approximately 100 volts and a frequency of approximately 13.5 MHz to the wafer for approximately 15-30 seconds to cause argon ions to impinge on the surface of the wafer and remove contaminant material therefrom;
• (c) advancing the wafer from the first reactor into a second reactor while maintaining unbroken vacuum conditions in the first and second reactors;
• (d) depositing a layer of metal on the surface of the wafer in the second reactor;
• (e) patterning the metal to form a predetermined metal interconnection pattern thereof;
• (f) performing a stabilization bake cycle on the wafer, measuring the TCR of the nichrome resistor material, and rejecting the wafer if the measured TCR is greater than a predetermined value;
• and
• (g) completing fabrication of the wafer.