Susumu Kasukabe

Method of manufacturing probing head for testing equipment of semi-conductor large scale integrated circuits

A probe head for use with equipment for testing a semiconductor device such as a large scale integrated circuit (LSI) includes electrode pads are formed on a circuit substrate, and a pad protecting conductive layer formed on the pads. A probe pin forming material is grown which is worked into a pin-like configuration, thereby improving a pin assembling property of a probe head portion and this realizes highly accurate pinning with high reliability.

RELIABILITY EVALUATION OF THICK FILM RESISTORS THROUGH MEASUREMENT OF THIRD HARMONIC INDEX

The degradation mechanism of ruthenium-based thick film resistors is investigated in accelerated tests under various conditions of humidity, temperature and overload stress. This study shows that the variation of resistance is mainly caused by hydration and dehydration in the conductive component RuO2: RuO2

Coalescence growth mechanism of ultrafine metal particles

Abstract Ultrafine particles produced by a gas-evaporation technique show clear-cut crystal habits. The convection of an inert gas makes distinct growth zones in a metal smoke. The coalescence stages of hexagonal plates and multiply twinned particles are observed in the outer zone of a smoke. A model of the coalescence growth of particles with different crystal habits is proposed. Size distributions can be calculated by counting the ratio of the number of collisions by using the effective cross section of collisions and the existence probability of the volume of a particle. This simulation model makes clear the effect on the growth rate of coalescence growth derived from crystal habit.

Contact properties of the spring probe for probing on a solder bump

Flip-chip solder bumps are formed on the area array electrodes of high-speed computer LSI chips. A high-density spring probe (600 probes/9 mm*9 mm) was developed for testing these LSIs by vertical insertion into the solder bumps. Solder with an extremely high lead content is used to lengthen the life for the soldered joint. This oxidized lead with high resistivity causes poor contact. Probing tests are conducted to find a suitable probe tip shape and processing conditions for 97 Pb/3 Sn solder bumps. Probe tips with adequately small opening angles easily break through the oxide film covering the solder surface and obtain sufficient contact area with the new surface of the solder bump. By using a probe with a tip opening angle of 30 degrees , contact resistance remains stable when a probe is inserted into a solder bump before melting into a spherical shape.<<ETX>>

Membrane probe with pyramidal tips for a bare chip testing

Bare chips are used in multichip modules for high packaging density and high processing speed devices. Obtaining known good dies (KGD) is a significant problem in achieving high MCM yields. Therefore, a probing technique for bare chips with high reliability is a matter of importance. In order to achieve good contact properties at a low probing pressure, a new membrane probe with pyramidal tips is developed for bare chip testing. By using anisotropic etching of silicon, quadrangular pyramidal pits are formed as the cast of probe tips. By nickel plating these pits, nickel pyramidal tips with copper wiring are formed on the polyimide film. The silicon wafer cast is then dissolved completely by etching. This membrane probe is then attached to a socket. This pyramidal probe is vertically inserted into an aluminum pad. Contact resistance remained stable at 0.1-0.2 /spl Omega/.

Technique for the control of the crystal habit of ultrafine particles in the gas-evaporation technique

Abstract Magnesium ultrafine particles have clear-cut habits such as hexagonal plates and polyhedra. When magnesium is evaporated downwards using a tube with holes at the bottom, hexagonal plates are formed exclusively throughout the smoke. Their size is controlled by selecting an inert gas. The growth process of an hexagonal plate can be considered to be a coalescent growth of other hexagonal plates.

Growth mechanism and growth form of β-Ag2S whiskers

Abstract Silver sulfide whiskers grow on silver materials under a dry sulfur atmosphere at room temperature. This whisker is a β-Ag 2 S single crystal and the elongated direction is proved to be [100] by TEM. Silver ions diffuse through the Ag 2 S crystal up to the top of it and are sulfurized by adsorbed sulfurs. On the basis of this growth mechanism, the growth from of dendritic crystal can be considered by using a “resistor network model”. This model makes clear the effect on the growth form derived from the restricted supply of silver ions or sulfur.