Veeco Mark II User manual

Mark II⊕Controller
Technical Manual
425959

Mark II
Controller
Technical Manual

© 2003 Veeco Instruments Inc. All rights reserved.
Veeco Instruments Inc.
2330 E. Prospect Road, Ft. Collins, CO 80525
970.221.1807
The information contained in this document is believed to be accurate and reliable. However, Veeco Instruments Inc. cannot
accept any financial or other responsibilities that may result from the use of this information. No warranties are granted or
extended by this document.
It is the policy of Veeco Instruments Inc. to improve products as new technology, components and materials become avail-
able. Veeco Instruments Inc. therefore reserves the right to change specifications without prior notice.
This manual is intended for qualified personnel who are responsible for servicing and or running Veeco Instruments Inc. ion
beam processing systems and equipment. The information contained in this manual is the sole property of Veeco Instru-
ments Inc. and may not be reproduced, distributed, or transmitted in any form without the written permission of Veeco
Instruments Inc. Mark™II⊕is a trademark of Veeco Instruments Inc. All other trademarks are property of their respective
companies.
Manual #425959 Rev. I

1
Chapter 1: Safety
Understanding the correct installation, operation, and maintenance pro-
cedure is necessary for safe and successful operation. This safety alert sym-
bol precedes safety messages in this manual, along with one of the three
signal words explained below. Obey the messages that follow these words
to avoid possible injury or death.
This symbol marks an imminent hazard which will kill or injure if
ignored.
This symbol marks a potential hazard which may kill or injure if
ignored.
This symbol marks a potential hazard which may cause minor injury
if ignored.
This symbol marks a potential hazard which may cause damage if
ignored.
Please read the following before continuing:
To avoid electrical shock, keep clear of “live” circuits. Follow all
local lock-out/tag-out procedures before repairing or replacing any
electrical devices.
Obtain, read and understand the Material Safety Data Sheet (MSDS) for
any chemicals and materials referenced in this technical manual. Follow
all local procedures in the safe handling and use of these materials, includ-
ing the use of any required personal protective equipment.
It is recommended that only trained, qualified persons using established
safety procedures perform any work related to the installation, start-up,
operation or maintenance of this system. Qualified service personnel
should refer to the Mark™ series Source/Controller Troubleshooting
technical manual for detailed information.
DANGER
WARNING
CAUTION
CAUTION
WARNING

2
To avoid electrical shock, check that all hardware interlocks are
working. Keep all guards and panels in place during routine system
operation.
Complete ion beam systems from Veeco Instruments Inc. are supplied
with hardware interlocks and software safeguards at various points in the
system. Whenever components or retrofits are added to existing systems,
a local review of system safety is recommended.
To avoid electrical shock, disconnect the controller from any power
source before making connections to the source or other external
components.
Since the controller does not have an integral Mains Disconnect, the user
must provide a suitable external Disconnect switch for the controller.
Connect an additional 12 AWG (or larger) signal ground wire with
green/yellow colored insulation between the ground stud located on the
unit’s rear panel and the process chamber ground point to provide reli-
able controller operation.
This controller employs components which contain tin, solder and trace
amounts of mercury. Recycle or dispose of these items in accordance with
local environmental regulations.
To avoid possible environmental contamination, recycle or dispose
of this unit and any replaced components in accordance with local
regulations.
It is recommended that two persons move the unit by grasping the case at
the sides.
To avoid back and other injuries, two persons should move the con-
troller by grasping the case at the sides.
WARNING
WARNING
CAUTION
CAUTION

3
Symbols Used on the Controller
Refer to manual
Designates a chassis ground
Designates a protective earth grounding point
Dangerous voltage
Unit in standby – power outputs deactivated
Unit on – power outputs active
Unit off – power off

4
Chapter 2: Overview
The Mark II Controller is factory configured for use with Veeco’s
Mark/Mark series gridless ion source. The unit is able to automatically
adjust the filament current, anode voltage and gas flow rate to provide an
ion beam with user chosen values for energy and current. An optional
interface package is offered to make the controller plug compatible with
existing Mark series power supplies, permitting drop in replacement for
automated systems.
The unit’s modular power supplies may be operated in one of two modes.
In the MANUAL mode, each power supply module runs independently.
All relevant parameters may be adjusted, including source gas flow. The
mass flow controllers (MFCs) may also be turned on or off. The auto-
matic start sequence is disabled in this mode.
In the AUTO mode, the controller monitors and adjusts all parameters to
achieve the target anode voltage, anode current and neutralization cur-
rent. The automatic start sequence is enabled when the BEAM button is
pressed. This sequence starts the source gas flow, and applies an anode
voltage as well as a filament current to start the source. Once the source
starts, the controller adjusts: the filament current (to achieve the desired
neutralization) and source gas (to achieve the desired anode current).
Maximum filament currents and gas flows can be entered.
Figure 2.1 Mark II Con-
troller

5
This Mark series Controller includes:
•Anode Supply – The anode supply is an isolated switching
power supply that produces a DC potential needed to accel-
erate the electrons until they have enough energy to ionize
gas atoms to sustain source discharge.
•Filament Cathode supply – The filament cathode supply is
an isolated switching power supply that produces an AC
waveform needed to heat the filament cathode to emission
temperature.
•Gas Flow Controller – The gas flow controller is designed to
control up to four external MFCs as well as a positive shut-
off valve for each. Analog control is provided with future
capability for digital control (EIA-485).
•User Interface – The LCD touch screen on the unit’s front
provides local controller access. This screen shows operating
parameters and event status (including alarm conditions).
•Remote Interface – Includes EIA-232 interface1which
affords unit access via a remote connection to an external
PC. The analog/digital controls duplicate the remote inter-
face available from an existing Mark series controller.
Press the parameter’s display bar on the touch screen to change its value
on the numeric keypad that appears. Target parameters are displayed
when a particular module is off; actual values are displayed when the
module is on. Six parameters are displayed on the touch screen. Some
parameters vary depending on the operating mode.
All adjustable parameters can be changed remotely with the user friendly
command set. See “Serial Communications Protocol” on page 61.
When remote operation is enabled, the touch screen can be intentionally
locked out to prevent unauthorized access. The unit’s switch closure
input and output communicate status information to an external PC or
control system. The input allows on/off beam control; the output indi-
cates beam status.
Each MFC channel may be configured for the valve size, calibration gas
and process gas to be used. Secondary MFC channels may be assigned a
ratio to control their flow rate relative to the primary (source) MFC
channel. Start flows and run ratios may also be specified for each second-
ary channel, simplifying gas mixture flow control during routine start-up
and operation.
1. Formerly known as, and identical to, RS-232.

6
Chapter 3: Operating Principles
This chapter explains the functions necessary for successful operation. It
is intended to help the user understand how the source and controller
function together. Information and recommendations are offered to
avoid unexpected operating circumstances which may cause equipment
damage. It is suggested that this material be read before using the unit for
the first time and used as a reference if questions arise during routine
operation.
Source Considerations
The Mark II Controller has been designed to power the Mark/Mark
series end-Hall Effect type gridless ion source and neutralizer. This source
type creates a beam of ions through the interaction of electric and mag-
netic fields in the source’s discharge region. Ions accelerate away from the
anode with an energy that depends on where they were created. The
mean ion beam energy is typically 60% of the discharge voltage. The
actual ion beam current is typically 20% of the discharge current. The dis-
charge current is a function of the anode voltage, the source gas flow, and
the emission current. The controller automatically adjusts these indepen-
dent system variables to maintain the target operating condition. Refer to
the ion source’s technical manual for additional information.
Controller/Power Supply Function
The automatic start sequence is enabled when the BEAM button is
pressed and the controller is in AUTO mode. This sequence initiates
ramping the source gas flow to the start gas flow setting. Next, the Anode
Voltage , VA, is increased until it reaches the user selected starting value.
Then, the cathode is heated to thermionic emission temperature by the
cathode supply. The filament current rises until there is a source discharge
or until it reaches its target value.
The discharge is initiated by electrons that are accelerated toward the
anode and strike neutral atoms or molecules, thereby generating ions.
This gaseous mixture of electrons and ions constitutes a discharge plasma.
The interaction of the electrons in this plasma with the magnetic field
also establishes the electric field that accelerates the ions. This accelera-
tion has significant components in both the radial and axial directions.
The accelerating potential varies over the discharge region; ions are pro-
duced with a substantial spread in energy, depending on their position at
ionization.

7
For steady state operation, the unit adjusts the gas flow and anode supply
until the anode current and voltage are at the target values. The cathode
supply is adjusted in response to neutralization current changes until the
Emission Current, IE, is larger than the Anode Current, IA, by the speci-
fied neutralization current offset or ratio. Current neutralization of the
ion beam leaving the source is approximately obtained with equal anode
and emission currents. An electron deficiency may lead to high plasma
potential throughout the process chamber, which can cause arcing. A
small excess of electrons (approximately 10%) is generally enough to fully
neutralize the beam and prevent this arcing. These neutralizing electrons
are obtained by making the cathode current slightly larger than the anode
current. Several current paths exist in the discharge region, as shown in
Figure 3.1.
The electron current in the discharge region, referred to as the glow frac-
tion current, IGLOW
, is not directly measured by the controller. The sum
of the glow current and ion beam current is measured by the system and
is displayed as Anode Current by the controller. The downstream ion
beam draws an electron current from the filament that is sufficient to
space charge neutralize the beam plasma (assuming the cathode is hot
enough to supply the required current). This electron current ultimately
flows to the process chamber ground or substrate. The Emission Current
is displayed by the unit. The current returning to the controller from pro-
cess chamber ground (the difference between ion beam current, IBEAM
and ISUB) is called the neutralization, or Neutralizer Current,INEUT.
The controller calculates the difference between IA and IE, which it dis-
plays as INEUT. Recall that the mean ion energy corresponds to about
Figure 3.1 Equivalent Cir-
cuit Diagram
"SUBSTRATE"
CHAMBER
GROUND
CATHODE
SUPPLY
ANODE
SUPPLY
CONTROLLER
MASS FLOW
SOURCE INDUCED
AC NOISE CURRENT
V
A
NEUT
CATH
CATH
SUB
BEAM
SUB
GLOW
EQUIVALENT CIRCUIT DIAGRAM
A
I CONTROLLED BY m
V SELF REGULATED
A
I CONTROLLED BY I
NEUT CATH
I NEUT

8
60% of the anode voltage. For example, the ion energy should be about
90eV for an anode voltage of 150V. Operation is typically possible over
an ion energy range of 40 to 180eV.
If the process chamber has other rapidly changing gas supplies (e.g., reac-
tive gases introduced at the substrate), pressure fluctuations may occur at
the source’s anode region during routine operation. Since the anode cur-
rent is pressure dependent, the anode supply may exhibit an over-current
condition in response to a pressure burst. The unit compensates with
automatic current limiting in response to this burst, and will attempt to
restart if the discharge goes out. If a discharge cannot be restarted, the
controller will turn off after a timed period.
To avoid thermal damage to the source’s mechanical components
from excess current over an extended period, use conservative gas
flows whenever the controller is operating in MANUAL mode.
Gas Flow Controller Function
The neutral gas flow introduced to the ion source is regulated by a ther-
mal mass flow controller (MFC) attached to a supply of working gas. The
mass flow value appears on the display bar on the unit’s front panel. This
flow determines the gas pressure inside the source and therefore the elec-
trical resistance of the plasma discharge. More gas causes the resistance to
decrease and the discharge current to increase.
The mass flow is a controlling variable of discharge current, which leads
to a complication in the control loop compensation design. Because pres-
sure fluctuations travel at a finite speed (the speed of sound), there will be
a delay in any change of the actual flow downstream of the MFC in
response to a change in its valve position. The standard anode current
control parameters are designed for a time delay using argon. If heavier
gases are used (such as xenon), or if non-standard gas lines are used, con-
trol loop parameters may need to be adjusted for stable operation. In this
case, contact “Service Support” on page 39 for recommendations and
assistance. Refer also to “Mass Flow Controller(s)” on page 12 for gas
line length recommendations. These values assume laminar flow condi-
tions.
To maintain laminar flow conditions, avoid introducing abrupt
changes in line diameter or sharp bends in the line; these will induce
turbulent flow and change the mass transport delay characteristic.
CAUTION
NOTE

9
Chapter 4: Installation
Inspection
Unpack the Mark II Controller and inspect it carefully for any visible
damage. If damage is found, notify the shipping company and Veeco
immediately. Check that all accessories and options have been included
with the unit.
General
The controller is designed to be mounted in a standard 19 inch equip-
ment rack. The unit’s top, back and sides should be inaccessible when the
controller has electrical power and is operating. Refer to “Mechanical” on
page 46 for additional information on the unit’s mechanical characteris-
tics and to “Interface Connections” on page 50 for pin assignments on
all external device connections.
To avoid thermal shut down and possible damage, allow enough
clearance for air flow to the cooling fan in the back panel as well as
the side panel vents.
Connection
Read all instructions before connecting power. Refer to “Specifica-
tions” on page 44 for detailed installation requirements.
Figure 4.1 Controller -
Rear Panel
CAUTION
NOTE

10
Follow these steps to connect the controller (Refer to ”Figure 4.1” on
page 9 and to the “Drawings” on page 40):
1. Check that the ON/STANDBY and Mains Disconnect switches are
in the OFF position before continuing.
To avoid electrical shock, keep clear of “live” circuits. Follow all
local lock-out/tag-out procedures before continuing.
2. Connect the source cable to
a. the SOURCE connector on the unit’s rear panel
b. the receptacle on the atmosphere side of the source’s electrical
feedthrough on the process chamber.
Refer to the respective technical manual(s) for installation and start
up information.
3. Attach the user supplied interlock cable to
a. the INTERLOCK connector on the controller’s rear panel
b. the external interlock circuit.
To avoid controller damage, do not wire the external interlock to a
powered circuit.
4. Connect the cable(s) between the appropriate connector(s) on the
unit’s rear panel and the MFC(s). The cable type and rear panel con-
nector used depends on the MFC’s communication protocol (analog
or digital).
The digital MFC feature is not active at this time.
5. If the unit will be controlled with a remote computer, connect the
EIA-232 cable to
a. the REMOTE connector on the controller’s rear panel
b. the remote computer.
Route all signal cables at least 0.5m (20 in.) from power and source
output leads to avoid inducing interference.
WARNING
NOTE
CAUTION
NOTE
NOTE

11
6. If the unit will have positive shut-off (P.S.O.) valve(s), connect the
cable(s) between the appropriate row on the GAS FLOW P.S.O.con-
nector on the controller’s rear panel and the user supplied P.S.O.
valve(s) and power supply.
7. Make the following source gas connections:
a. the gas supply and the MFC’s gas input connector
b. the gas line between the MFC’s gas output connector and the
P.S.O. valve (if used)
c. the P.S.O. valve (if used, or MFC, if not) and the atmosphere side
of the source’s gas feedthrough to the process chamber.
8. Attach the controller’s external ground connection to the process
chamber.
9. Attach the controller’s power cable. Refer to the “Specifications” on
page 44 for more installation information.
It is the user’s responsibility to meet all local and national electrical
codes when installing this equipment.
The unit is ready to power up.
Source
For best results, use the feedthrough(s) provided with the source and the
cable furnished with the controller to connect these devices. Refer to
”Figure 4.1” on page 9. If the recommended feedthrough is not used,
ground the ion source body to the process chamber close to where the
unit is grounded on the atmosphere side of the chamber. These two
grounding points should not be separated by a bolted joint in the process
chamber.
Refer to the respective technical manual(s) for installation and start
up information.
Attach the controller’s external ground connections to the process cham-
ber. This controller ground connection is in addition to the safety ground
wire in the line cord, and is required to prevent ground loop currents
from adversely affecting source operation.
NOTE
NOTE

12
The unit has separate ground connections for user safety. To avoid
electrical shock, maintain the safety ground connection during rou-
tine operation.
Interlock Connector
The INTERLOCK connector is wired in series with pins on the output
SOURCE connector. Refer to ”Figure 4.1” on page 9. The controller
interlock is made when: the source cable is attached to the SOURCE
connector and the user provided external interlock string is attached to
the INTERLOCK connector. The unit’s outputs are disabled if either the
source cable is disconnected at the rear panel or the interlock string is
open (the touch screen remains active). Refer to “Interlock” on page 50.
If there are two or more interlocked shut-off switches in the system,
the system interlock allows these switches to be connected in series.
Mass Flow Controller(s)
It is recommended that the gas outlet is located within 1.8m (6 ft.) of the
gas port(s). Use ¼ in. OD stainless steel tubing for the gas line and a
reducing union between this tubing and the gas feedthrough. Gas type
and gas line length downstream of the MFC may affect source-controller
operation; refer to “Gas Flow Controller Function” on page 8. Avoid
switching tubing diameters along the gas line unless necessary. Diameter
changes may greatly increase the delay before a flow change reaches the
ion source. If heavier gases are used (such as xenon), or if non-standard
gas lines are used, control loop parameters may need to be adjusted for
stable operation. In this case, contact “Service Support” on page 39 for
recommendations and assistance. Separate electrical connectors are pro-
vided for analog and digital MFCs (although the digital MFC feature is
not active at this time). Refer to “Gas Flow Connectors” on page 53.
Refer to the MFC’s technical manual for additional information on
this device.
Positive Shut-off Valve
An MFC is not intended to function as a positive shut-off device and will
not be leak tight when closed. The GAS FLOW P.S.O. connector has
pairs of dry closure contacts (no voltage is supplied) intended to open up
a normally closed shut-off valve located upstream or downstream of each
of four MFCs. Refer to “Gas Flow Connectors” on page 53.
WARNING
NOTE
NOTE

13
It is the user’s responsibility to provide power to actuate the P.S.O.
valves. Refer to the technical information provided with the valves.
Remote Communication
There are two methods of remote communication: analog (via a legacy
protocol) and digital (using the EIA-232 command set). A single
REMOTE connector has pin assignments for each method. Refer to
“Remote Operation” on page 33 for detailed information.
NOTE

14
Chapter 5: Operation
General
Refer to “Installation” on page 9 to verify that the Mark II Controller
is ready to power up before continuing. Confirm that installation and
start-up information in the source technical manual has been followed as
well.
These instructions are presented for local operation with the touch
screen. Remote operation using Virtual Front Panel software
(optional) and a PC (provided by others) may be slightly different.
Start-up
Follow these steps when operating the unit for the first time, or if the sys-
tem has not been operated for a while.
Chamber Pumpdown
Evacuate the process chamber to the desired operating pressure and hold
this pressure until significant out-gassing subsides. This interval is some-
what process dependent. Good vacuum practice helps to reduce the wait
time.
Controller Power Up
To energize the controller:
1. Turn the Mains Disconnect switch (provided by others) to the ON
position.
2. Turn the ON/STANDBY switch on the controller’s front panel to
the ON position. The unit’s start-up sequence begins.
Start-up is complete when the touch screen looks similar to ”Figure
5.4” on page 19.
Screen selections may be made by using the touch screen (in LOCAL
mode) or by the user supplied computer (in REMOTE mode). The
touch screen selection is typically made by a touch-and-lift motion,
NOTE
NOTE

15
rather than by simply touching. If the wrong screen area is touched,
keep finger contact with the screen and slide off the button before
lifting away.
The controller is ready to receive configuration information for your sys-
tem.
Beginning Automatic Operation
This section explains how to configure the unit and prepare it for routine
operation. Here is a brief summary of the steps required:
MFC Configuration – If the source and controller were purchased
together, MFC configuration settings were entered at the factory. If the
MFC range or source gas changes, refer to “MFC Configuration” on
page 16.
Gas Line Purging – Air becomes trapped in the gas line(s) during initial
device/controller installation and whenever the process gas changes. Use
the steps under “Gas Line Purging” on page 20 to remove trapped air
from the process gas supply line(s).
Auto Mode Configuration – These modes offer different levels of user
influence over controller operation. One is used to compensate for per-
formance differences between the Mark controller and legacy equip-
ment. Changing modes also changes the analog inputs used to influence
the unit’s control algorithms. Refer to “Remote Operation” on page 33
for detailed information on analog inputs. The parameters and control
modes are:
• Anode Start Voltage
• Anode Current
• Emission Current.
Refer to “Auto Mode Configuration” on page 21 for more information.
AI Servo Configuration – The Anode Current (AI) Servo Configuration
settings permit the user to fine tune anode current/gas flow control loop
operation. Refer to “Gas Flow Controller Function” on page 8 and “AI
Servo Gain” on page 71. More specifically, the user may:
• match source type to gain factor
• adjust source-controller performance to optimize process
• tailor source-controller performance to existing hardware
• manage process transients

16
The AI Servo Configuration selections are only applicable when the
ANODE CURRENT CONTROL MODE (on the Auto Mode Con-
figuration list) is set to Anode Current Setpoint. Refer to “Auto
Mode Configuration” on page 21 for details.
Enter Adjustable Parameters – A Source Run Data sheet is provided
with each new Mark series ion source. The factory tested parameters
recorded on this data sheet are: anode current and voltage, neutralization
current, filament current, emission current, source gas flow, and process
chamber pressure. The Source Run Data sheet offers useful reference
information on source-controller performance at the time of shipment.
Operating parameters from existing systems may be utilized instead.
Source Gas Start Flow –The source gas start flow needed to successfully
initiate a discharge plasma depends on: the gas type, the vacuum system’s
pumping speed and other system and/or process related characteristics.
Refer to “Source Gas Start Flow” on page 28 to identify this parameter.
The unit retains the parameters entered before its last run. Compare
these values to those on the Source Run Data sheet before re-enter-
ing any data.
MFC Configuration
Several MFC-specific values and parameters must be set in the unit before
operating the source. They are accessible from the Select Function dialog
box which opens with the UTILITIES button.
These parameters are:
• the MFC’s range
• the gas used to calibrate the MFC
• the gas to be run in the MFC
•thegasflowlimit.
NOTE
Other manuals for Mark II
1
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