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Flow Solutions

1640
Pressure-Based Mass Flow Controller
For Ion Implant Applications
The 1640 Pressure-based Mass Flow Controller is a metal-sealed instrument designed
to meter and control gas flows in low-line pressure applications where thermal mass
flow controllers are limited in their ability to accurately measure flow. The 1640 utilizes
the principle of sonic flow through an orifice, a condition met when the upstream control
pressure is at least twice the downstream pressure. Under these conditions, mass flow is
proportional to the control pressure.
In the 1640, as illustrated in Figure 1, a Baratron® capacitance manometer monitors thepressure upstream of the critical orifice. This pressure is proportional to mass flow. The
measured pressure is compared in the control electronics to the flow set point. A control
signal is then generated to drive the proportional control valve to the conductance required
to bring the actual control pressure (flow) into agreement with the flow set point.

Features & Benefits
Maximize Gas Utilization

Ease-Of-Use• Control of gas flow at pressures below
10 Torr improves SDS® gas utilization
and reduces frequency of source bottle
changes• Same footprint and electrical 			specifications as thermal Mass Flow 		Controllers allows for straight forward 		
integration

Robust• Pressure-based flow measurement withBaratron® pressure transducer provides
repeatable flow measurement andcontrol over full inlet pressure spectrum• Rigorous metal-sealed design andSTRIFE testing ensures long term
reliability

Safe Delivery System (SDS®) Applications
The 1640 was the first MFC to enable SDS gas utilization
at source pressures below 10 Torr. Configurations of the1640 have been designed specifically for the requirements
needed for flow control in ion implanters utilizing SDS
dopant sources. The SDS source pressure is typically at650 Torr when the source is full, and drops as the source
gas is extracted. The 1640 PMFC is designed to extract
gas below source pressures of 10 Torr (see Figure 2). The
1640 PMFC thus improves source utilization and reduces
the frequency of source bottle changes (see Figure 3).
The 1640 for SDS applications is designed to function
over the wide SDS source pressure range from 650 Torrto below 10 Torr and provide Full Scale dopant flows ashigh as 10 sccm. Since flow is controlled by controllingpressure there is not as much pressure coefficient effectas there is with most thermal MFCs. The 1640 is in use
today on medium and high current as well as high energy
implanters throughout the world. 1640s are also available
for high pressure implant gases.

PId Control
Electronics

Proportional
Control
Valve

Baratron ®
Capacitance
Manometer

Controlled
Pressure(P1)
Orifice

Inlet
Pressure

OutletPressure(P2)

Figure 1 —A cross-section view of the 1640 pressure-based Mass Flow Controller.

Figure 2 —Figure 3 —This graph shows pressure drop versus flow rate for two 1640 MFCs: one
with 12 sccm Full Scale, the other with 6 sccm Full Scale.

The 1640 design allows for gas extraction to source pressures below 10Torr depending on flow rate and gas line conductance. A 1640 designedfor 6 sccm Full Scale has the potential to extract 5% more SDS source gas
than a competitor’s thermal MFC.

Specifications
Full Scale Ranges For Implant Applications (N2 equivalent)2 sccm to 20 sccm

Maximum Operating Inlet Pressure				5 psigMinimum Operating Inlet Pressure (typical)			

below 10 Torr

Overpressure Limit				

45 psia

Control Range (typical)				

5% to 100% of F.S.

Flow Accuracy (including non-linearity, hysteresis, and			non-repeatability referenced to 760 mmHg and 0°C)

Gas/flow rate dependent				Repeatability				± 0.2% of F.S.

Resolution				

0.1% of F.S.

Temperature Coefficients
Zero				Span				< 0.02% of F.S./°C< 0.2% of Rdg./°C

Warm-up Time 				< 30 min (to within 0.2% of F.S. of steady state performance)

Controller Settling Time to 100% of F.S.				

< 5 sec (typical per SEMI Guideline E17-91)

Normal Operating Temperature Range				0°C to 50°C

Input Voltage Required
Max. current at start-up (first 2 sec)				
Typical current at steady state				± 15 VDC (± 5%) @ 200 mA± 15 VDC (± 5%) @ 100 mA

Set Point Command Signal				0 to 5 VDC from < 20K Ω

Output Signal				0 to 5 VDC into > 10K Ω

Output Impedance				<1ΩConnector Types				15-pin Type “D”

Wetted Materials
Standard wetted components				
Valve seat only				316L S.S., nickel, Inconel®
Kel-F®, Chemraz® or Kalrez® (gas/application dependent)

Leak Integrity
External (scc/sec He)				
Through closed valve1 				< 1 x 10-9
1% of F.S. (nitrogen) at 15 psig inlet to atmosphereFittings Compatible With				Swagelok® 4 VCR®

Compliance				CE 				1To assure no flow-through, a separate positive shut-off valve is required.

Safe Delivery Source (SDS®)The SDS delivers gas based on the differential pressure between thesource gas cylinder (at less than 0 psig) and the implanter ion source.
An MKS Baratron pressure transducer with an LDM (Local Display Module)
may be used to sense source pressure along with the 1640 pressure-based
MFC to control flow.

Ordering Information
Ordering Code Example: 1640AXXXCode			1640A Pressure Based Mass Flow Controller

1640A

Configuration
1640A

MKS will configure the 1640 to meet your specific needs for gas type and flow rates. 			
XXX
Please contact the MKS Applications Engineering Group at (800) 227-8766 with your			requirements and allow them to determine an appropriate 1640 configuration.
Optional Accessories
750 Baratron Capacitance Manometer: to monitor the gas source pressure			LDM: A local display module that, when mounted with the 750, provides a local
pressure readout
Cabling for 1640A:
CB259-5-10 for 1640 15-pin Type “D” to 246, 247				
CB147-1-10 for 1640 15-pin Type “D” to 647
Contact Applications Engineering for shielded cables required for CE Compliance.

Dimensional Drawing —Note: Unless otherwise specified,dimensions are nominal values in inches(mm referenced).

1640 - 1/18
© 2005-2018 MKS Instruments, Inc.
All rights reserved.

MKS Instruments, Inc.
Global Headquarters

MKS Instruments, Inc.
Flow Solutions

2 Tech Drive, Suite 201
Andover, MA 01810

Six Shattuck Road
Andover, MA 01810

Tel: 978.645.5500			
Tel: 800.227.8766 (in U.S.A.)
Web: www.mksinst.com

Tel:978.975.2350

MKS products provided subject to the US Export Regulations. Diversion or transfer contrary to US law is prohibited.
Some Baratron® capacitance manometer products may not be exported to many end user countries without both US andlocal government export licenses under ECCN 2B230.
Specifications are subject to change without notice. mksinst™ is a trademark and Baratron® is a registered trademark of MKS
Instruments, Inc., Andover, MA. Kalrez® is a registered trademark of E.I. Dupont Co., Inc., Wilmington, DE. Chemraz® is a
registered trademark of Greene, Tweed & Co., Kulpsville, PA. Kel-F® is a registered trademark of 3M Company, Minneapolis,
MN. Swagelok® and VCR® are registered trademarks of Swagelok Marketing Co., Solon, OH. SDS® is a registered trademarkof Matheson Tri-Gas and ATMI, Inc. Inconel® is a registered trademark of Inco Alloys International, Huntington, WV.