Frequently Asked Questions

Desk V Questions

The Desk V HP has a 6” (~15cm) diameter chamber. Inside, the standard specimen table is 2” (5cm) diameter and can tilt and rotate (without the etch option). We can upgrade the sample stage to a flat 4” (10cm) diameter but the sample can only rotate, it will not tilt. If a larger sample size is required, it would fit better in the Bench Top Turbo.

For carbon evaporation, the coatings are quite uniform over the 4” (10cm) diameter size. Topography of the sample can cause shadowing. And carbon particulates can also be known to affect the coating thickness uniformity if they fall from the carbon source onto the specimen during coating. The Bench Top Turbo geometry allows coating the specimen while the carbon source is not directly above the sample. If any particles fall from the carbon, they do not land on your sample.

The monitor will last for many years and is covered under the Denton standard 12-month warranty. The gold coated quartz crystals themselves need to be changed periodically when there is a thick build-up of coating on them.

The process is fast. Total time to pump down and evaporate the carbon is in the minutes range, usually less than 10 minutes. A 0.125” reduced cross section of 0.040” diameter will deposit about 100 Å of carbon.

In the Desk V units, the sample must be relatively thin (on the order of 1” or less).

We do incorporate a safety interlock that will only power the carbon accessory when the vacuum interlock is satisfied. There are not built-in safeguards for eye protection; we recommend welding glasses or similar.

Compressed gas is not required. In the event that the unit is used for sputtering, argon is optional and room air can sometimes be used.

With an initial pressure of < 20 mTorr, a source-to-substrate distance of 2.375 inches (60 mm) using a timed sputter setting of 10 minutes (600 seconds), you can reasonably expect:

For gold, using air at 50 mTorr, a film thickness between 260 and 1750 angstroms and a deposition rate of between .43 and 2.92 angstroms, depending on power percentage and current applied (mAmps).

For gold/palladium using air at 50 mTorr, a film thickness between 405 and 2210 angstroms and a deposition rate of between .68 and 3.68 angstroms, depending on power percentage and current applied (mAmps).

For gold, using argon gas at 50 mTorr, a film thickness between 640 and 3360 angstroms and a deposition rate of between 1.07 and 5.60 angstroms, depending on power percentage and current applied (mAmps).

For gold/palladium, using argon gas at 50 mTorr, a film thickness between 560 and 2795 angstroms and a deposition rate of between .93 and 4.66 angstroms, depending on power percentage and current applied (mAmps).

General Questions

Denton provides a limited warranty and begins at the time the system passes Acceptance Testing at Denton’s Facility. If no Acceptance Test is conducted, warranty period begins the moment it is shipped from Denton’s Facility.

The SN can be found on a sticker or plaque located on the back panel of our equipment.

Yes, these are tool- and location-dependent and quoted upon request.

To schedule a visit, call 1-856-439-9100 and ask to be connected to the Service Department. A visit cannot be guaranteed until a valid Purchase Order or payment is in place.

Yes, upgrades include: software and automation controls, addition of heat, rotation, sources, transfer mechanisms, and gate valves.

There is no one cleaning process which is “right” for all vacuum systems, vessels or components. Here are a few considerations you should be first mindful of:

• The level of vacuum required (rough, high, UHV, etc)
• Performance requirement (e.g. low desorption)
• Particular contaminant (e.g. hydrocarbons) whose partial pressure must be minimized
• Safety
• Cost

To clean the vacuum chamber, Denton recommends that you bead blast the dirty components that you can easily remove from the system (using glass beads), then lightly brighten the surface using alumina impregnated sand paper. Following the sanding, the surfaces should be chemically washed through a series of baths including trichlor, acetone, alcohol and deionized water. Denton suggests an ultrasonic bath for these rinses, with cycles of 5 minutes per fluid.

To clean stainless steel components, use a cleaner approved for use with stainless steel. Non-abrasive cleaners and scouring pads are recommended to preserve the surface finish. Scrapers and non-metallic scouring pads may be used on heavily soiled areas. If scrapers are used, caution must be used to not damage the chamber surface. Rinse all areas with water using a sponge or towel. Dry thoroughly.

Pump-down times depend on a number of variables, including chamber size, pump types and capacities, application environment and wafer preparation to name but a few of these variables. The pumps chosen (pump down capacity rates) and chamber size (total volume) affect pump-down times. But where the pumping takes place also affects pump-down times (compare ISO clean room 1 versus 9; or any clean room versus a warehouse without humidity control, for example). Additionally, how the wafers are prepared and handled affect pump-down times; wafers handled and prepared with contamination-elimination in mind would provide faster vacuum pump-down times than would wafers handled without care and preparation.

As you might imagine, then, tool size, pumping configuration, environment and material readiness all drive and dictate vacuum pump-down times. Given this, Denton works with customers who regard pump-down times critical to their application and process. Most pump-down time variables can be controlled in a real and measurable way.

Denton Vacuum uses the most efficient and effective vacuum pressure gauges available with respect to the specific vacuum deposition tool and the customer’s application requirements. Typically, our customer requirements entail use of a one-wire (Pirani) or ionization (Bayard-Alpert hot cathode) [or a combination of one-wire and hot cathode].

Fifteen (15 kW) is generally the maximum but output power is dependent upon the number of pockets (containers of materials) and amount of those materials (cubic centimeters) to be deposited.

Denton Vacuum employs two options for thin-film deposition monitoring: an optical monitoring system (OMS) or a quartz crystal sensor monitoring system.

The OMS measures and controls the termination of deposition of material on a substrate by using the reflection off of—or transmission through—a substrate or witness chip. By measuring light at a known single wavelength and measuring the intensity of the reflection or transmission of light across the chip, the quarter-wave thickness of the layer of material on the substrate may be determined, and the deposition terminated at the desired optical thickness. Advantages of an OMS include:

• Direct monitoring of the substrate or indirect monitoring of a separate witness chip or chips
• Reliable, precise step sequencing of all actions required in a process
• Dependence on refractive index of the substrate, the refractive index of the film material and the phase thickness of the deposited film
• Direct measurement of optical performance of the device or part
• Operates at process temperatures
• Excellent for complex, multilayer optical stacks

Quartz crystal monitoring systems measure thin film thickness on substrates by tracking the frequency response of a quartz crystal during the coating process.

Quartz crystal monitoring system is comprised of three main functional components: the quartz crystal sensor, a temperature-controlled housing or “sensor head” and electronic monitor or controller that forces the crystal into vibration and tracks the frequency of this vibration over time. An internal microprocessor then converts this frequency into the actual thickness of the film.

For an effective quartz crystal monitoring system, each of three components possesses critical operational characteristics: for the crystal, its frequency range, resistance and electrode quality; for the sensor holder, temperature regulation ability and electrode ruggedness; for the monitor, its ability to track accurately the crystal frequency changes and temperature characteristics.

Denton Vacuum’s ProcessPro® provides users in production, development and research with tools and features that assure consistency, repeatability, productivity and yield. For those of our customers in a multi-user environment, Denton supports up to 40 different users, with different logins and different levels of access, ideal in multi-user operations.

ProcessPro® tools and features include:

Operator Interface: Windows interface with a fully visualized system layout. Password access for multiple users.

Integration: full control of pumps, valves, power supplies, cathodes, gauging, gas flow control, and setpoints. Fully automatic operation.

Recipe Management: operating control via a comprehensive and complete recipe structure. Includes off‐line recipe writing.

Datalogging: Comprehensive process data logging.

Remote Access: Ethernet connection allows users or service personnel (including Denton Vacuum service personnel) to remotely access the system for monitoring, diagnostics, and software upgrades. That is, with ProcessPro’s remote access, Denton can distribute software updates and modifications and provide diagnostic and debugging support to anyone, anywhere in the world.

Additionally, Denton’s provides its customers an uncompiled code set that allows the user access to the actual software as written, enabling code changes optimized to fit our customers’ needs. Last, ProcessPro, based on GE’s Cimplicity, is supported globally by General Electric.

There are two primary considerations when selecting a crucible: chemical and thermal compatibility. There are a number of resources available on the web for determining crucible chemical compatibility of most common deposition materials. The following can help guide you.

Thermal compatibility concerns the cracking of the crucible during evaporation. As molten materials conform to the shape of the crucible, differences in thermal expansion rates can cause the crucible to crack. There are several things you can do to avoid the cracking of your crucible:

  • Use a metal liner. They can withstand the difference in expansion rates.

If not using a metal liner:

  • Limit the amount of material in the crucible so as not to cover the bottom
  • Ensure that all material evaporates from out of the crucible before allowing it to cool
  • Do not fill crucible more than ¾ full with non‐subliming materials

Some applications require a liner, including those evaporating materials that react with the crucible material itself and those in which the evaporating melting materials expansion rates are greater than that of the crucible material itself. You can purchase crucible liners made with the following materials:

  • Molybdenum
  • Tantalum
  • Tungsten
  • Nickel

Denton recommends the following goggles: 5469T5 welding goggles, shade # 6 and 5424T38 filter lenses, shade # 9 available online at

Co-deposition involves more than one deposition source being deposited at the same time. Co-deposition provides a mixture of two or more materials on a sample. Caution must be employed so as not to cross-contaminate the deposition sources. Sequential deposition involves deposition of one source after another has been completed. Sequential deposition provides separate and definitive multiple films on a sample.

DC sputtering uses DC current while RF sputtering uses AC current (at 13.56 MHz). DC sputtering works on conductive materials only; AC sputtering can be used on any material.

  • Electrical: 208 VAC (+/- 5 %), 50/60 Hz, 3 phase, 80 amp (estimated)
    • Panelized control with single entrance protection by a heavy duty disconnect switch with “lockout” provision, as provided by Denton Vacuum.
    • Cooling water: 30-35 l/min, 15-25 degrees Centigrade, 3-4 bar differential between supply and return (6 bar maximum inlet pressure);
    • Compressed air: 10-20 l/hr, normal dry shop air, 6-7 bar (system valve operation):
    • Dew point: maximum of 2 degrees Centigrade
    • Oil content: 1-5 mg/m3
    • Foreign particles, size: max of 5 microns. Concentration: max of 5 mg/m3
  • Nitrogen: (preferentially evaporated from liquid N2):
    • 0.5 bar (chamber venting, 100 l/cycle, optional)
    • 0.5 bar (loadlock venting, 10 l/cycle, optional)
  • Process gas: 5N purity:
    • 0.5 bar (customer supplied)

Denton provides all system documentation in a USB thumb-drive format, after configuration and supply of the system, and includes:

  • One operating instruction manual to include preventive maintenance procedures/timetable, troubleshooting guides.
  • One set of sub-assembly vendor manuals
  • One set of required electrical schematics
  • One set of required mechanical drawings

Denton employs its proprietary ProcessPro and uses a GE-Fanuc programmable logic controller to drive all system operations.
To manage this industrial-grade PLC, Denton developed the ProcessPro HMI (human machine interface). Built on GE’s Cimplicity controls platform and operating on a Windows platform, ProcessPro provides users at every level with unique features that enhance productivity and yield.

Users in the production environment will find distinct operating modes for production operators, real-time visualization of system operations, full programmability of setpoints and alarms, and an email alert feature that allows the system to send alarm messages to designated individuals by email. Remote diagnostics are also supported, enabling user staff to view the system operation anywhere in the facility, or (with user permission) allowing Denton to remotely access the system to provide software updates and process or operations support including PLC-level diagnostics.

Delivered system includes user licenses for the operating software and the complete, uncompiled code set. While almost all users turn to Denton for ongoing software support, with an uncompiled code set customers can turn to GE for software support or themselves make necessary modification. The Denton ProcessPro package has been in use for over a decade, and Denton continues to provide long-time customers with upgrades and support for their ProcessPro configured systems.

Denton’s Process Pro® controls system is a state-of-art control software that has been under continuous development at Denton for almost fifteen years. It is a Windows 10 based human-machine interface that links to and drives a highly reliable, industrial grade GE-Fanuc PLC (programmable logic controller). It enables the development and execution of complex deposition profiles.

ProcessPro control software configured for specific system layout, including integration of power supplies, pump controllers and other key, third party supplied components.

Full, automatic creation of single and multi-layer processes by Excel spreadsheet.

Full remote setpoint capability:

  • Gas flow rates
  • Total chamber pressure during PID pressure control
  • Multiple operation modes:
    • Manual
    • Automatic
    • Maintenance
    • Automatic process sequence generation and editing, and film program generation and editing.
  • Comprehensive process data logging
  • Remote access via system’s Ethernet connection; user-controlled remote Denton access for software upgrades and service and process support
  • Programmable email notification of alarms

Denton Vacuum provides many fixtures to hold your substrates, including the following:

  • Bulk water cooled stage
  • Confocal non-biasable (water-cooled shaft)
  • Confocal single rotation
  • Domes
  • Flip dome assembly
  • Flip fixture assembly [laser bar]
  • Flip fixture paddle
  • Hollow shaft rotation with spider cage or flat rack
  • Knudsen planetary assembly
  • Lift-off single rotation (indexable)
  • Light weight single rotation (o-ring)
  • Planetary assembly
  • Single rotation with flat plate or spider cage (with center feed throughs)
  • Single Rotation with spider cage
  • Target turrets

Back streaming refers to pump oil that gets into the process chamber. To minimize this entry, a foreline trap is placed between the pump and the process chamber. Foreline traps consist of liquid nitrogen and water-cooled traps or an ambient baffle. To prevent and eliminate back streaming, a dry pump is often employed. Elimination and prevention can also be achieved by using a cryopump.

If the turbo-molecular pump is valved off from the chamber and at atmosphere, the turbo pump can be turned on after the mechanical pump has started and the foreline valve is open. If the turbo-molecular pump is open to the chamber and both are at atmosphere, the turbo pump can be turned on after the chamber pressure is less than 1 torr.

A load lock is an auxiliary chamber attached to a process chamber usually with a gate valve between the chambers. A load lock allows samples to be transferred into the process chamber without venting the chamber to atmosphere. Load locks often have their own high vacuum pumping system and venting, and typically possess a sample holder and a mechanical transfer mechanism to move samples to and from the process chamber.

Use a load lock when you need to reduce sample processing cycle times or potential for contamination in the process chamber. While at atmosphere, samples are loaded into the load lock chamber, which is then pumped down to a high vacuum pressure.

Vacuum valves serve three main functions: isolate vacuum volumes from each other or pumps; control gas flow to achieve a particular pressure; and enable transfer of objects between vacuum volumes.

When using electron beam guns or sputtering guns powered by RF or DC sources, Denton Vacuum recommends, in good manufacturing practice and safety, to always ground the chambers using a 3-inch copper strap. This 3-inch copper strap acts as a collector for any RF signal that may be generated during the normal operation of the coating process. To properly make this connection, attach one end of the copper strap to the chamber and attach the other end to either grounding rods or structural building steel. When using structural steel, be certain to scrape off any paint or dirt before you make your connection.