Innovations in semiconductor fabrication processes have driven process shrinks partly to fulfill the need for low power, system-on-chip (SOC) devices. As the process is innovated, it influences the related design debug and failure analysis which have gone through many changes. Historically for signal probing, engineers analyzed signals from metal layers by using e-beam probing methods [1]. But due to the increased number of metal layers and the introduction of flip chip packages, new signal probing systems were developed which used time resolved photon emission (TRE) to measure signals through the backside. However, as the fabrication process technology continues to shrink, the operating voltage drops as well. When the operating voltage drops below 1.0V, signal probing systems using TRE find it harder to detect the signals [2]. Fortunately, Laser Voltage Probing (LVP) technology [3] is capable of probing beyond this limitation of TRE. In this paper, we used an LVP system to analyze and identify a functional shmoo hole failure. We also proposed the design change to prevent its reoccurrence.

The oxidation behavior of X20 steel in steam environments was studied isothermally between 580-640°C. Initially, the magnetite (Fe 3 O 4 ) phase formed on the surface. With increasing time and temperature, the hematite (Fe 2 O 3 ) phase formed. The oxide scale consisted of an inner layer divided from an outer layer by the original metal surface. A Cr-rich area was observed beneath the original metal surface. Oxide scales formed on a serviced boiler tube at 540°C for 7000h were also analyzed and found to be similar in oxide phase composition to those formed on X20 steel under laboratory conditions. However, differences existed in the microstructure and distribution of the Cr-rich area within the oxide scale. It was concluded that the oxidation mechanism under field conditions differs from that under laboratory conditions.