TABLE OF CONTENTS The wafer-fabrication process requires a high degree of precision in process control, equipment operation, and material manufacture. One process mistake can render the wafer completely useless. One "killer" defect can ruin a die. Throughout the process, a variety of tests and measurements are made to determine both wafer quality and process performance. The tests take place on in-process wafers, test die and production die, and the finished circuit. Individual tests are described in this chapter. Statistical process control programs are addressed in Chapter 15.
Upon completion of this chapter, you should be able to:
Explain the difference between resistance, resistivity, and sheet resistance.
Draw a sketch of the parts and current flow in a four-point probe.
Compare the principles and uses of color interference, fringe counting, spectrophotometers, ellipsometers, and stylus for film thickness measurements.
Compare the principles and uses of groove and stain, SEM, and spreading resistance for junction depth measurements.
List the methods and advantages of microscope and SEM inspection of wafer surfaces.
Draw sketches of diodes in forward and reverse bias and their companion current-voltage curves.
Explain the effect of surface current leakage on a junction performance characteristic.
Draw sketches of a bipolar and MOS transistor in operation and their companion current-voltage characteristics.
List the process steps for a capacitance-voltage measurement and the principle of contamination detection.
Describe the principle and use of atomic force microscopes.
Characterization of processes and circuit parameters is required for...
