THE
BROOKHAVEN INSTRUMENTS CORPORATION LENSMASTER
The Brookhaven
Instruments Corporation’s Lensmaster is a plug-compatible high-voltage power
supply for use on various models of Varian’s medium-current ion implanters. The
Lensmaster has supervisory circuits not to be found in the original equipment
as supplied with the implanter. These new circuits provide protection against
the loss of wafers during production. New high-voltage leads, from the
Lensmaster to the lens’ feed-throughs, are provided with the unit. The output
voltages are 0 to 10 kV (two positive and two negative) and they track with
energy. The ‘A’ voltages and the ‘B’ voltages increase or decrease
appropriately with the adjustment of the ‘Balance’ potentiometer.
One major
advantage of the Brookhaven Lensmaster is the inclusion of a fault detector
board, similar to that of the Scanmaster. The supervisory circuits detect if
any one of the four outputs becomes missing. When the (fault) condition is
detected, an alarm sounds, the appropriate LED illuminates, and the machine is
placed in a hold condition. Other new circuits also detect a difference between
the absolute values of the A+ and A- (also B+ and B-), and if the difference is
10% or more, the fault detector board will sound an alarm, flash the
appropriate pair of LEDs and stop the process.
Another advantage
of the Lensmaster is an active load for the positive supplies. If the beam hits
the lens, the supply will sink the current as opposed to the output going up in
voltage or just exploding. The positive supplies can sink 4 mA of beam current.
A third advantage is 4 LCD meters mounted on the front panel giving a direct
indication of the output voltages (output divided by 1000). The Lensmaster
installs in the place of the old scanner DC supply, so a machine with the
vacuum tube amplifiers would have to accept the unit mounted on top or some
other place (this place on a machine with a scanmaster is likely not utilized).
A third connector
on the rear panel brings the divided-down outputs out so that a customer with a
PCT-type system could monitor and interlock the lens supply if so desired. A
Lensmaster was tested on a 300XP ion implanter on Sept 28, 2004 at a fab in north Texas. It performed very well from low energy
to high energy. Their test wafer indicated sheet resistance was normal.
Specifications
--- Lensmaster
Brookhaven P/N: 35520460
Input Voltage: 0 to +10 VDC as per
original equipment.
Input
Connectors: 7-pin Hex connectors and a 14 pin
Outputs: Four
individual outputs, 0 to 10 KVDC. The A+ and B+ outputs are positive and the A-
and B- outputs are negative. The outputs track with machine energy.
Output
Monitoring: Individual LCD displays (4), on the
front panel, display output voltages. A connector on the rear panel of the
instruments allows for remote monitoring. All output-monitoring signals
represent the output voltage divided by 1000.
Fault
Detection: Typical time from the occurrence
of a fault until implantation is stopped is 20 mSec. Types of faults monitored
are missing output voltages and A+ not equal to A- and B+ not equal to B-.
Dimensions: Standard 19” rack mount,
10.5” tall, and 15.3” deep.
Weight: 26 pounds.
Mounting: The
unit will be located in the place of the old scanner power supply, immediately
below the location of the existing lens power supply.
Power Requirements: 120 VAC ± 10%, 50/60 Hz.