Veeco Mark II User manual
Mark II
Fluid Cooled Ion Source
with HCES
Technical Manual
© 2006 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 available. 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. This product is protected by one or more of the following patents: US Patents - 7,342,236; 7,439,521; 7,425,711;
7,476,869; 7,566,883; Korean Patent – 10-0860931; other regional patents pending.
Manual # 427361 Rev. D
1
Chapter 1: Safety
Understanding the correct installation, operation, and maintenance pro-
cedure is necessary for safe and successful operation. This symbol pre-
cedes 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.
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.
Ion source surfaces may exceed 300°C (570°F) after use and venting.
Avoid burns during servicing by using appropriate personal protec-
tive equipment and allowing for a sufficient cool down interval.
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.
DANGER
WARNING
CAUTION
CAUTION
WARNING
CAUTION
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.
WARNING
3
Chapter 2: Overview
Congratulations on your purchase of the Veeco Mark™II fluid cooled
ion source with hollow cathode electron source. The gridless end-Hall
design offers operational flexibility and reduced sensitivity to contamina-
tion from the surrounding environment. This ion source’s high-current
density, total beam current and low energy beam characteristics facilitate
a variety of property enhancement and reactive processes. It is particularly
well suited to industrial vacuum applications involving:
•Precleaning – Low energy ion beam precleaning removes
surface contaminants (water vapor, hydrocarbons, native
oxides and absorbed materials), to improve film/substrate
adhesion.
•Ion assisted deposition – Ion bombardment of the substrate
assists film growth, adhesion and hardness while reducing
absorbed residual gas contaminants and film stress.
The ion’s accelerating potential difference is generated with a magnetic
field and a substantial electron current. The source generates a maximum
beam current of approximately 2 to 3A (for argon and oxygen) with a
mean ion beam current energy that can range from 40 to 200eV, depend-
ing upon the source's input settings. Typical operating gases include
argon, krypton, xenon, nitrogen and oxygen. For reference, basic operat-
ing characteristics have been included for argon and oxygen. Refer to the
“Specifications” chapter for details.
The source consists of the following basic elements:
• stainless steel anode and exterior shell
•magnet
• input gas distributor
• gas and electrical feedthroughs and connections
• hollow cathode electron source (HCES)
• fluid cooling and fittings
• gold plated fasteners.
The source and feedthroughs have been engineered for straightforward
installation and ease of use. If you do need help, Veeco’s “Service Sup-
port” team is available to assist you.
4
Chapter 3: Theory of Operation
The Mark series gridless ion source operates by producing a low pres-
sure gas discharge or plasma (typically 0.13 to 1.33x10-1Pa/0.1 to 1.0
x10-3 Torr) near a cusped magnetic field that lies between an electron
emitter (either a filament or a hollow cathode) and an angled anode. FIG-
URE 3.1 illustrates this ion source’s basic operating principles. A DC
magnetic field is formed by a permanent magnet and the source’s open-
ended magnetic stainless steel shell. Primary electrons, emitted from the
cathode, are drawn to the cone-shaped anode by means of an applied DC
potential, through which a working gas is injected. The accelerated elec-
trons strike and ionize the input gas’s neutral atoms or molecules to form
a gas discharge or plasma. As the electrons drift toward the anode, the
magnetic field impedes their mobility or flow. This resistance to electron
flow results in a space charge (or potential field) within the plasma near
the anode. It is this spatially varying potential field that ultimately acceler-
ates ions away from the source anode (both axially and radially), to form
the source's gridless ion beam. Since ions can be produced at various
locations along the plasma space-charge, the output beam current’s
energy distribution and angular spread is broadly distributed. The mean
ion beam current energy is typically 60 to 80% of the anode potential. In
the absence of electrostatic grids to separate electrons from ions, a near
equal number of electrons in the plasma are electrostatically drawn along
with the ions, essentially neutralizing the ion beam. It is often necessary
for many applications to inject additional electrons from the cathode into
the ion beam; this further enhances neutralization and decreases positive
charging of electrically isolated surfaces or work-pieces.
FIGURE 3.1 Schematic Dia-
gram of Ion Source Opera-
tion.
IA
e-
VA
Energy (eV)
Ion Current Energy
Distribution
Electron
Source
(Cathode)
Anode
Mean ion current
energy, <EB>, is about
60-80% of VA
Neutralized
Ion Beam
Input
Gas
S
S
Relative Distance from Anode
Discharge
Space
Potential
Typical operating vacuum
pressure: 0.1-1 mTorr
NS
Ion Source Shell
VA
+
5
”FIGURE 3.1” on page 4 shows the Mark series ion source’s fundamen-
tal operating principles; FIGURE 3.2 illustrates fluid cooled source opera-
tion, together with its HCES, the Veeco Mark series Controller and
both input mass flow controllers (MFC). The ion source and HCES
require separate MFCs. These components are all provided when this
model is ordered as a package.
First, an argon plasma is ignited in the HCES and sustained with current,
IK, provided by the controller’s keeper supply. This supply maintains the
HCES’s thermionic emission temperature, to produce the primary elec-
trons. Second, a gas flow is introduced into the source; the unit applies a
voltage-regulated anode potential, VA, to drive the ion source discharge
and produce the ion beam. The controller is able to then automatically
regulate the gas flow to the anode, since the electrical impedance of the
plasma between the anode and cathode depends on input gas conditions.
This provides an anode discharge current IA, approximating the operator
requested set point as closely as possible.
The power supply uses a third current-regulated emission supply (posi-
tioned between the cathode and the anode supply return) to provide
additional electrons from the HCES to enhance ion beam neutralization.
This emission supply regulates a portion of the cathode return current,
IE, most of which is the anode supply return current, IA, and any addi-
tional neutralization current, IN, returning through the chamber system
ground. By regulating IE, the controller allows the operator to inject an
excess electron neutralization current, IN. The recommended value for
INis +10 to +20% of the anode current, IA. Refer to the Mark series
Controller technical manual for detailed information.
FIGURE 3.2 Ion Source-
HCES-Controller Operation
with MFCs.
IAe-
Anode
Input
Gas
S
S
NS
VA
+
IK+
HCES
(Cathode)
Mark II+
Controller
Source Mass
Flow Controller
(MFC)
IE+IK
IE+
IN= (IE -I
A)
Ion Source
HCES Mass
Flow Controller
(MFC)
6
Recall that the mean ion beam current energy is typically 60 to 80% of the
anode voltage setting. Total output ion beam currents are similarly 20 to
30% of the anode current; this beam current is generally less at low gas
flows (high anode voltages) and greater at high gas flows (low anode
voltages). The output performance depends upon a particular vacuum
system’s actual pumping capacity, because of the interaction between the
source output and the process chamber’s background gases. Stable opera-
tion is generally possible for VA typically ranging between 50 to 300V and
for IAbetween 1 to 15A, depending on gas chemistry and the local pro-
cess chamber’s vacuum pressure.
Mark series Controller output is limited to 3kW. Refer to “Specifi-
cations” on page 63.
Additional information and reference performance curves for routine
operation appear in“Source Performance” on page 65.
Low vacuum pressures (less than 1.33 x10-1 Pa/1.0 x10-3 Torr) are gen-
erally necessary for stable source operation at high anode voltages
(greater than 200V); as a result, vacuum systems with marginal pumping
capacity may not support high voltage operation. A pumping capacity
greater than or equal to roughly 700 /s should be adequate for most
applications; this assumes there are no additional gas flows into the pro-
cess chamber other than those of the ion source and HCES.
NOTE
7
Chapter 4: Installation
Inspection
Unpack the Mark series fluid cooled ion source and inspect it carefully
for any visible damage. If damage is found, notify the shipping company
and contact “Service Support” on page 62 immediately. Check that all
accessories and options have been included with the source package.
The Mark anode assembly is shipped separately from the source
body. The anode assembly must be mounted in the base assembly
before operating the source in the process chamber. Refer to ”FIG-
URE 6.16” on page 44 and Step ”6.” on page 44 for detailed instruc-
tions.
General
Install and furnish utilities to the ion source. Where appropriate, refer to
“Drawings” on page 73 and “Specifications” on page 63.
It is the customer/installer’s responsibility to install this equipment
in accordance with current local electrical and mechanical code
requirements, in addition to any applicable national regulations.
This chapter is divided into the following sections:
• Verify Facilities
• Source Mounting
• Feedthrough Installation
• Vacuum Side Connections
• HCES Installation
• Atmosphere Side Connections
• Electrical Continuity
• Controller Interlocks
• Post Installation.
NOTE
NOTE
8
Verify Facilities
The following is a check list of recommended facilities and components
required to install and operate the ion source with the HCES.
•Vacuum System – The process chamber’s low pressure vac-
uum system must be capable of base-pressures of 1.33 x 10-2
Pa (1.0 x10-4 Torr) or less, with sufficient vacuum pumping
capacity to maintain operating pressure between 0.67 and
1.33 x10-1Pa (0.5 and 1.0 x10-3 Torr) for the maximum gas
flow listed in the “Specifications” on page 63. This corre-
sponds to a approximate vacuum pumping capacity of at least
700 /sec.
•Gas Supply and Control – The source has been tested for
argon operation; it will operate with other inert gases, as well
as oxygen and nitrogen. Refer to “Facilities Requirements”
on page 64 for detailed information. Each source and HCES
requires a separate MFC, which is provided by Veeco when
the source is purchased as a part of a package. It is recom-
mended that the customer install a two stage regulator
upstream of the MFC and a positive shut off valve down-
stream for each MFC.The HCES is designed for inert gas
operation only.
•Cooling – The ion source is fluid cooled, and the HCES is
radiation cooled. Refer to “Facilities Requirements” on
page 64 for additional information.
Ion source surfaces may exceed 300°C (570°F) after use and venting.
Avoid burns during servicing by using appropriate personal protec-
tive equipment and allowing for a sufficient cool down interval.
•Electrical – The Veeco Mark series Controller provides the
currents, voltages and gas flow control needed for source/
HCES operation, and is provided by Veeco when the source
is purchased as a part of a package. Refer to the controller
technical manual for installation, connection and operational
information.
•Mechanical – These items are customer supplied unless
noted:
•a 1
/8in. OD stainless steel gas delivery tube that is clean
of all contaminants and is appropriately rated for vacuum
service within the intended process environment.
• Vacuum/process suitable hardware and bracketry to make
a fixture that secures the ion source base plate to the pro-
cess chamber. This fixture must capably bear the ion
source and HCES's weight. Refer to “Specifications” on
CAUTION
9
page 63 for weight and “Drawings” on page 73 for
source envelope dimensions.
• Three process chamber penetrations (for coolant, gas and
electrical) capable of holding a vacuum seal, which match
the customer specified feedthroughs ordered with the
source package. Veeco offers the following feedthrough
styles: 1 in. O-ring seal or 2¾ in. metal seal.
Source Mounting
Verify that there is sufficient clearance at the intended location in the pro-
cess chamber to install and hook up the ion source and HCES before
continuing. Refer to “Drawings” on page 73 for source envelope dimen-
sions. The ion source may be installed in any orientation. Veeco recom-
mends positioning the source so that the operator may readily remove the
anode assembly and HCES for maintenance while leaving the base assem-
bly, with its electrical, gas and coolant connections in place. This is espe-
cially important when installing the source in large process chambers
(deeper than 1m/39 in.).
To reduce the likelihood of repetitive stress and strain injuries when
performing routine preventive maintenance, install the source in an
ergonomically accessible location and position.
Follow customary clean room protocols and methods to keep all vacuum
side parts free of oil, particles, fibers and other contaminants.
Wear clean, lint free, powder free examination gloves before han-
dling the source, its feedthroughs or any vacuum side mounting
hardware.
The HCES, anode assembly and base assembly are separated for ship-
ment. ”FIGURE 4.1” on page 10 shows how these components will be
reassembled during initial installation as well as routine servicing. Refer
to ”FIGURE 6.16” on page 44 and step ”6.” on page 44 for detailed
instructions on anode assembly alignment and seating in the source body.
CAUTION
NOTE
10
1. Attach the ion source base assembly to the process chamber, using
clean hardware and bracketry (provided by others) via the four slot-
ted bosses on the base assembly. Refer to “Drawings” on page 73.
2. Verify the following before continuing:
• Confirm that there is no interference between the source’s
base assembly and existing vacuum and mechanical fixtures.
• Check that the supplied connections and leads can easily
reach between the source and the feedthroughs without plac-
ing undue stress on them. Refer to “Drawings” on page 73.
• For best results, verify that any ion source beam shutter or
other mechanical boundary (when used) has approximately
5cm (2 in.) of clearance from the filament cathode at the
source’s output.
• Temporarily hold the HCES in its mounting position, to
confirm that the body and its 1/8in. gas line do not come in
electrical contact with any conductive surfaces in the process
chamber.
The HCES will be installed later.
If any lines and leads do not easily reach the feedthroughs, relocate
the source, or contact “Service Support” on page 62 regarding the
availability of other electrical lead lengths.
FIGURE 4.1 Mark II Grid-
less Ion Source with HCES.
NOTE
11
Feedthrough Installation
These steps describe the installation of a 1 in. O-ring feedthrough, but
are also applicable for installing a feedthrough using a 2¾ in. metal seal
flange. Refer to “Drawings” on page 73 when following these steps.
1. Remove any blanking plates or plugs installed in the chamber pene-
trations intended for feedthrough use. Confirm that the penetration
size and type matches the feedthrough supplied. Contact “Service
Support” on page 62 if there are any discrepancies.
If feedthroughs using a 2¾ in. metal seal are used, confirm that the
chamber penetration’s flange, inner diameter and length do not
interfere with making vacuum side feedthrough connections.
2. Clean all vacuum mating surfaces and seals (O-rings or gaskets) of
oils, particles, fibers and other contaminants, using an alcohol moist-
ened lint-free task wipe.
3. Secure the coolant and gas feedthroughs to the process chamber; do
not complete any of the atmosphere side connections at this time.
4. Remove the following hardware from 1 in. base plate electrical
feedthrough assembly:
a. the atmosphere side electrical connector, by first removing the
three pan head screws from the outside edge of the end-connec-
tor housing (atmosphere side).
b. the retaining nut and washer.
To avoid possible feedthrough damage, do not bend or attempt
removal of any of the electrical pins.
5. Check that the sealing surface is clean and free of scratches. Insert the
base plate electrical feedthrough into the 1 in. chamber penetration
from the vacuum side, placing the O-ring against the chamber inte-
rior.
6. Secure the feedthrough from the atmosphere side, using the washer
and the retaining nut; hand tighten with a 1½ in. open end wrench.
To avoid possible feedthrough thread galling, do not overtighten.
NOTE
CAUTION
CAUTION
12
7. Replace the atmosphere side electrical connector:
a. Align the connector’s keyway with the feedthrough’s keyway.
Refer to FIGURE 4.2.
b. Secure the connector to the feedthrough by tightening the three
pan head screws. Refer to FIGURE 4.3.
FIGURE 4.2 Align the Con-
nector and Feedthrough Key-
ways.
FIGURE 4.3 Secure the Con-
nector to the Feedthrough.
13
Vacuum Side Connections
Swagelok®brand unions used inside the process chamber should be
assembled finger tight, after initially seating the ferrules with open
end wrenches. This prevents galling and makes equipment servicing
easier.
1. Measure the distance between the 1
/
8in. Swagelok brand gas input
connection on the source’s base assembly and the gas feedthrough’s
vacuum side; cut an appropriate length of customer supplied 1
/
8in.
OD stainless steel tubing for the vacuum side source gas line.
2. Join the source gas connection and the gas feedthrough using the
tubing; seat each fitting using 7
/
16 and ½ in. open end wrenches.
3. Attach the flexible vacuum side coolant lines (supplied with the
source package) to the female ¼ in. VCR®brand fittings on the
source’s base fixture. Make certain to include ¼ in. VCR brand gas-
kets. Compress each fitting using 5/8and ¾ in. open ended wrenches
until the connection is vacuum tight.
4. Repeat step 3. for the vacuum side coolant feedthrough connections.
The source’s internal cooling loop is symmetrical; either connection
may serve as inlet or outlet.
5. Attach the source’s vacuum side electrical lead assembly to the electri-
cal feedthrough. Two lengths are available: 18 or 36 in. (0.46 or
0.91m). These leads are factory connected to the source; field discon-
nection is not recommended. Electrical feedthrough pin assignments
are similarly factory configured, and do not require field changes or
adjustment.
The two remaining vacuum side electrical leads are for the HCES
and will be connected during that device’s installation. The
The source leads should remain slack and flexible after installation.
Avoid tight bends (under 5cm/2 in. radius of curvature), stretching,
or compression by other components.
o To avoid lead damage and diminished source performance, keep the
source leads loose and flexible.
NOTE
NOTE
NOTE
CAUTION
14
6. The HCES, anode assembly and base assembly are separated for ship-
ment; refer to ”FIGURE 4.1” on page 10. Remove the anode assembly
from the package, as well as any protective caps or covers.
7. Install the anode assembly in the source body; refer to ”FIGURE
6.16” on page 44 and step ”6.” on page 44 for detailed instructions
on anode assembly alignment and seating in the source body.
To avoid source damage, do not operate the ion source unless the
anode assembly is installed in the base assembly.
HCES Installation
The HCES and its bracket attach to the ion source’s mount plate. The
HCES requires gas and electrical connections similar to the ion source.
Refer to HCES 5000 technical manual for additional information.
1. Attach the HCES assembly to the ion source’s mount plate, using
two 10–32 screws and a 5
/
32 in. hex ball driver. There are three possi-
ble mounting locations.
2. Measure the distance between the “gas in” Swagelok®brand fitting
on the HCES assembly and the gas feedthrough’s vacuum side; cut
an appropriate length of customer-supplied 1/8in. OD stainless steel
tubing for the vacuum side HCES gas line.
3. Join the HCES “gas in” fitting and the gas feedthrough using the
tubing; seat the fittings on each end using 7/16 and ½ in. open end
wrenches.
4. Check the alignment of the keeper aperture and the cathode tip’s ori-
fice by looking into the discharge end of the HCES. Adjust the align-
ment if necessary. Refer to HCES 5000 technical manual.
To avoid electrical shorts and possible HCES - controller damage,
maintain at least 5cm (2 in.) clearance between the isolated gas line/
cathode and any conductive surface within the process chamber.
5. Attach each of the HCES electrical leads between the HCES and the
electrical feedthrough:
a. The keeper lead has a ¼ in. through-hole lug and attaches to the
HCES body via the ¼–20 x ¼ in. long hex socket cap screw,
using any of the HCES’s six unused ¼–20 threaded holes.
CAUTION
CAUTION
15
b. The cathode lead has a #6 screw through-hole lug that attaches to
the angled tab on the HCES mounting bracket with the #4–40 x
3/8in. long hex socket cap screw.
To avoid possible hollow cathode tip poisoning, refrain from: clean-
ing the HCES or the cathode tip with isopropyl alcohol or hydrocar-
bon solvents, and operating the HCES using reactive gases (oxygen
or nitrogen). The presence of residual solvents or oils will irrevers-
ibly damage the HCES tip and disrupt source start-up.
Atmosphere Side Connections
1. Flush any construction material (cutting oil, thread compound, PTFE
tape, metal particles or other contaminants) from newly plumbed
lines (gas and coolant) before attaching them to the process chamber.
2. Install the ion source and HCES mass flow controllers near the two
pin gas feedthrough provided with the source. For best results, Veeco
recommends locating the MFCs no more than 0.5m (19 in.) from
the input gas feedthrough. Provide secure vacuum tight connections
between the MFC gas outputs and the gas feedthrough at the process
chamber wall.
Shorter gas line distances ensure that the local ion source gas pres-
sure stabilizes quickly, improving source start-up and responsiveness
to changing process settings and conditions.
3. Attach the inlet and outlet coolant supply lines on the atmospheric
side of the coolant feedthrough. Refer to “Specifications” on
page 63 for detailed requirements. Check for and repair any leaks
inside and outside the process chamber before continuing.
4. Follow the steps in the Installation chapter of the Mark series Con-
troller technical manual to complete the connections between the
atmosphere side gas feedthrough and the facility’s gas service. Refer
also to “Drawings” on page 73.
Mark the source’s atmosphere side gas inlet line to avoid confusion
with any other process chamber gas service.
5. Connect the source cable to the electrical feedthrough’s atmosphere
side. Two lengths are available: 20 or 40 ft. (6.1 or 12.2m). Perform
CAUTION
NOTE
NOTE
16
the steps in “Electrical Continuity” before connecting this cable to
the controller’s rear panel.
To avoid possible source and/or controller damage, perform all con-
tinuity checks after source installation, but before connecting the
source cable to the controller.
After installation, the source may be serviced without the need to discon-
nect the base assembly from required facilities.
Electrical Continuity
For best results, check for electrical shorts and continuity between the
vacuum side source/HCES electrical connections and the source cable’s
end before attaching it to the controller’s rear panel. Connections may be
checked from either the atmosphere or vacuum side. Use the pin assign-
ments in Table 4.1 as a guide.
To avoid possible source/controller damage, do not attach the
source cable to the controller or turn the controller on before con-
firming the following electrical checks.
1. Use a multimeter to verify continuity between the controller end of
the source cable assembly to the respective vacuum side connections.
Continuity should be less than 1Ω.
2. Once continuity is verified, use a multimeter to confirm that the
anode, keeper, and cathode connections are isolated from one
another and from ground. Isolation should be greater than 10MΩ.
Table 4.1: Feedthrough Receptacle Pin Assignment
Cable Pin no.Feedthrough Pin Letter
(atmosphere side) Connection
1Danode
6 C HCES cathode tip
5B
HCES keeper
body
3/connector
shield A/connector body ground/return
CAUTION
CAUTION
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