Abstract:
The principles described herein relate to methods for soldering electrode terminals, pins or lead-frames of commercial electric components for high temperature reliability. In one embodiment, prior to soldering the electric components, a pre-plated solder layer is removed from the lead frame or pins, and nickel and/or gold films are formed with electroless plating. The removal of the pre-plated solder layer avoids excess pre-plated Sn with high-Pb solder that lowers the melting point to between 180°C and 220°C and weakens solder joints. The nickel layer formed with an electroless plating acts as a barrier to the interdiffusion of tin from solder with copper of the lead frame material, which may otherwise occur at high temperatures. Interdiffusion forms an intermetallic compound layer of copper and tin and degrades solder joint strength. The novel soldering processes improve high temperature reliability of solder joints and extend electronics life-time.
Abstract:
Methods and apparatus for creating a velocity profile of a formation surrounding a borehole by checkshot measurements while moving the tool (202) along the borehole. A conveyance and a sensor section (202, 205) are configured to move the sensor section (205) in the borehole. At least one receiver (205) is configured to detect signals generated at or near the surface while the sensor section is moving in the borehole.
Abstract:
Methods of manufacturing printed circuit board assemblies include placing a semiconductor chip having a plurality of lead terminals on a board formed with a plurality of solder lands at its surface such that each of the plurality of lead terminals is in touch with a corresponding one of the solder lands; supplying a solder material on the plurality of lead terminals and the plurality of solder lands; supplying a flux including mono salt of adipic acid and alkyl secondary amine; and locally heating the plurality of lead terminals such that the solder material and the flux are melted to join together the lead terminals and the solder lands.
Abstract:
Methods and apparatus for creating a velocity profile of a formation surrounding a borehole by checkshot measurements while moving the tool along the borehole. A conveyance and a sensor section are configured to move the sensor section in the borehole. At least one receiver is configured to detect signals generated at or near the surface while the sensor section is moving in the borehole.
Abstract:
Methods and apparatus for creating a velocity profile of a formation surrounding a borehole by checkshot measurements while moving the tool (202) along the borehole. A conveyance and a sensor section (202, 205) are configured to move the sensor section (205) in the borehole. At least one receiver (205) is configured to detect signals generated at or near the surface while the sensor section is moving in the borehole.