The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Jul. 25, 1989
Filed:
May. 24, 1988
John G Merullo, Andover, MA (US);
Gary B Tepolt, Andover, MA (US);
Other;
Abstract
In the coating apparatus disclosed herein, a semiconductor wafer is held on a vacuum chuck mounted on the spindle of a bidirectional servo motor. The servo motor is energized by a servo amplifier in response to the amplitude of the control signal provided to the amplifier. Dispensing means are provided for placing coating material on wafer held in the chuck. An oscillator is provided generating a periodic output signal of controllable amplitude and period. A programmable sequencer is operative in a first time period for appying the oscillatory output signal as a control signal to the servo amplifier thereby to angularly oscillate a wafer held in the chuck and for operating the dispensing means to place a predetermined amount of coating material on the wafer. The sequencing means is operative in a later time period for applying a fixed higher amplitude control signal to the servo amplifier thereby to spin the wafer and spread the coating material.