Maintenance Model 6DS-SP Planarizer
4 - 14 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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