Operations Model 6DS-SP Planarizer
2 - 30 Version 4.0 - February 1998
A velocity command signal from the control computer instructs the velocity
controller to ramp the motor up to the programmed speed. The gearbox turns
the shaft, subtable, and granite table all as one unit, accelerating to constant
speed. A resolver, mounted on the motor, feeds back the velocity and
acceleration of the assembly to the control computer. The speed of the table
is measured in revolutions per minute (RPM) and displayed in real time on
the monitor. Rated table speeds vary with the reducer ratio of the gear box
installed in the machine. Calibration variable 62 displays the table reducer
ratio. Note the ratios shown below:
7.5: 1 maximum 250 rpm
10: 1 maximum 160 rpm
15: 1 maximum 125 rpm
SPINDLE DRIVE ASSEMBLY
The spindle drive assembly consists of a brushless DC servo motor mated
with a gear reducer assembly, the quill shaft assembly, and the wafer carrier
mounting assembly. The motor mounting block and quill housing are bolted
together. They support the entire spindle drive assembly. The mounting
block serves as an attachment point for the spindle force assembly (discussed
further in the section below). The quill housing contains the quill shaft
assembly which rides on linear ball bushings inside the linear housing. The
linear housing is affixed to the bridge assembly framework. This
arrangement permits vertical movement of the spindle drive assembly. A
stop adjustment prevents the spindle drive assembly from contacting the
polish table whenever a wafer carrier is not attached to the end of the shaft.
The quill shaft assembly is the actual drive shaft which rotates the wafer
carrier on the polish table. Manufactured from two-inch steel stock with a
hollowed center, it rides inside the quill housing on linear ball bushings.
The brushless DC servo motor and reducer assembly mount directly to the
quill shaft. A bracket support and torque arm prevent its rotation. At the
bottom end of the quill shaft is a mounting flange supporting the wafer
carrier mounting assembly.
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