International Business Machines Corporation

Martin E Powell

John D Davis

Karen Lynne Holloway

Timothy J Wiltshire

Roger J Yerdon

Edward F Culican

Philip E Pritzlaff, Jr

Alexander L Martin

Holly A LaFerrara

A method and apparatus includes an integrated circuit device, and at least one alignment mark on the integrated circuit device, the alignment mark comprises a first coded region, a second coded region adjacent the first coded region, and a third coded region adjacent the second coded region, the second coded region located between the first coded region and the third coded region, and markings on the first coded region and the third coded region being identical.

Method for providing rotationally symmetric alignment marks for an alignment system that requires asymmetric geometric layout

An oscillator with noise rejection which may be used in a gate array in a semiconductor chip including a first amplifier circuit, a circuit, for connecting an external feedback element (crystal) across the input and inverting output of the first amplifier circuit for generating and amplifying a sine wave, and a circuit connected to the inverting output of the first amplifier circuit for generating a square wave with the duty cycle thereof being proportional to the difference between the center of the voltage swing of the amplified sine wave and a reference voltage. In a preferred embodiment, the first amplifier circuit and the generating circuit each include a current switch. A voltage reference network is provided to set the reference voltage for the current switch in the generating circuit to the center of the voltage swing of the sine wave applied to that current switch. This results in a 50% duty cycle square wave for the output signal. A current source voltage reference is included for ensuring that each of the current switches and the voltage reference network drive approximately constant equal currents.

Oscillator with noise rejection and square wave output

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Peekskill, NY, United States of America

Martin E Powell