Very highly purified water such as De-ionized (DI) water tends to become very corrosive once exposed to the atmosphere. This “Hungry Water” as known in the water purification world is known to be a major source of corrosion [1]. The DI water was responsible for corrosion of tin during autoclave (pressure cooker) testing of Integrated Circuit (IC) devices assembled in plastic Quad Flat Package (QFP) with fine pitch leads. The copper leads of these packages are plated with solder. The copper leads of the packages are plated with solder composed of Lead and Tin. Due to the effect of corrosive water, Tin from solder corroded during the autoclave testing and formed thin whiskers of solder. These whiskers created a leakage path between the leads causing the devices to fail for pin to pin leakage.

Latch-up induced during High Temperature Operating Life (HTOL) test of a mixed signal device fabricated with 1.0 μm CMOS, double poly, double metal process caused failures due to an open in aluminum metal line. Metal lines revealed wedge voids of about 50% of the line width. Triggering of latch up mechanism during the HTOL test resulted in a several fold increase of current flowing through the ground metal line. This increase in current resulted in the growth of the wedge voids leading to failures due to open metal lines.

During the ESD testing of a Dual T1/E1 line interface unit (LIU) at Level One, the circuitry in every pad cell was found to be robust to Electro-Static Discharge (ESD) threshold of up to 2000 Volts. Device failure was however observed on devices when functional tests were performed. These failures were observed on devices which were only subjected for 1250 Volts of ESD stress. The failure analysis revealed ESD induced damage at the Gate - Drain region of a MOSFET in the core of the die. A weak power supply clamp in the supply circuit caused this failure. The step by step analysis process and the redesign of this device with confirmation on new design revision is explained.