An instrument designer discusses the design, use, and limitations for optics based failure analysis tools for circuits. We will discuss conventional microscopes in the FA lab as well as emission microscopes, laser-based microscopes (e.g:, OBIRCH, TIVA), and infrared and ultra-violet microscopes. We will discuss the pain and gain of employing HgCdTe and InGaAs detectors for emission microscopes. We will also discuss infrared techniques for locating shorts from the back side including OBIC, OBIRCH, LIVA, TIVA, and XIVA laser techniques and locating faults with thermal infrared techniques.. Learning Objectives · Principles and techniques of basic and advanced light microscopy · Understand magnification, resolution and sensitivity limits of any microscope. · Introduction to infrared, ultraviolet and laser microscopy. · Learn the difference between OBIC, LIVA, OBIRCH, SEI, TIVA and XIVA. · Understand advantages and special limitations of HgCdTe or InGaAs emission microscope cameras