Texas Instruments Corporation

Dave Cotton

Taylor R Efland

Dale J Skelton

Ross Eliot Teggatz

Wayne T Chen

Roy Clifton Jones, Iii

Joe A Devore

Bill Grose

A thick copper interconnection structure and method for an LDMOS transistor for power semiconductor devices. A large LDMOS transistor is formed of a plurality of source and drain diffusion regions to be coupled together to form the source and drain. Gate regions are formed between the alternating source and drain diffusions. Each diffusion region has a first metal layer stripe formed over it and in electrical contact with it. A second metal layer conductor is formed over a plurality of the first metal layer stripes, and selectively contacts the first metal layer stripes to form a source and a drain bus. A thick third metal layer is then formed over each second metal layer bus, either physically contacting it or selectively electrically contacting it. The thick third level metal is fabricated of a highly conductive copper layer. The thick third level metal bus substantially lowers the resistance of the LDMOS transistor and further eliminates current debiasing and early failure location problems experienced with LDMOS transistors of the prior art. Other devices and methods are described.

Method for LDMOS transistor with thick copper interconnect

An improved waveform generator (,) permits digital spectrum spreading by employing circuitry for controlling the charging and discharging of a load capacitor (,) to alter the generator's base frequency. A charge/discharge circuit (,) modulates the currents into the capacitor (,) to effect the slope of the triangle signal waveform (,). A threshold detector (,) determines the amplitude of the base frequency. Switch logic (,) controls an array of 1/N current switches (,) that provide incremental values of a reference source (,) to a summing function (,) which, in turn, feeds a charge/discharge circuit (,). The energy of the triangle waveform (,) remains approximately the same only it is now spread over a range of frequencies with the amplitude of the signal at a given point less than the amplitude of the base.

Circuit and method for modulating the base frequency of a waveform generator

Ldmos transistor with thick copper interconnect

An interconnection structure and method for a multiple zener diode ESD protectoin circuit for power semiconductor devices. A plurality of lateral Zener diodes is formed. Each device is formed of a plurality of cathode and anode diffusion regions to be coupled together to form the cathode and anode of one or more Zener diodes. Each diffusion region has a first metal layer stripe formed over it and in electrical contact with it. A second metal layer conductor is formed over a plurality of the first metal layer stripes, and selectively contacts the first metal layer stripes to form a bus. A thick third metal layer is then formed over each second metal layer bus, either physically contacting it or selectively electrically contacting it. The thick third level metal is fabricated of a highly conductive material, such as copper. The resulting Zener diodes are coupled together in an ESD structure using the second level busses and the thick copper third level busses. The ESD structure of the preferred embodiment has low overall resistance and fast time to breakdown and provides excellent protection for the circuits to be protected. Other devices, systems and methods are also disclosed.

ESD protection structure using LDMOS diodes with thick copper

A method of efficiently turning off inductive loads includes turning off a driving switch, monitoring a circuit output during turn-off, and activating a control circuit in response to an inductive flyback voltage at the output which turns on a recirculation switch and recirculates residual load current and clamps the output thereby substantially decreasing power dissipation during inductive load turn-off.

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Plano, TX, United States of America

Dave Cotton