Tergeo RF plasma cleaner

Tergeo integrates multiple process control technologies to control critical parameters required for optimal plasma etching, plasma ashing and plasma cleaning processes. These include pressure and plasma sensing (see below) and automatic mass flow control of gas input. Operation is fully automatic, with an intuitive user interface featuring a 7″ touchscreen which make the operation as easy as a tablet device, with the embedded microcontroller supporting 20 customisable user recipes. PIE (Plasma Ion Electron) Scientific’s understanding of the importance of consistency and repeatability in scientific research and small scale production is embodied in the design of the Tergeo series to deliver every day reliability and repeatable performance.

Patent-pending plasma sensor technology
110mm diameter x 260mm deep quartz chamber
75W or 150W 13.56MHz high frequency RF power
Patent-pending plasma sensor technology
Direct or remote (option) plasma modes
Fully automatic operation with 20 recipe support
Job sequence mode operation for three cleaning steps
Two mass flow controllers (MFC) regulated gas inputs
Intuitive, touch-screen control
Pumping options to suit process
Vapour delivery option

Tergeo – the basics

Tergeo is a benchtop instrument with a quartz glass process chamber with that is 110mm ID and 280mm long to accommodate one 4” wafer. Tergeo-Plus uses a 75W 13.56MHz high frequency RF supply with auto-matching, which is adjustable from 1 to 75 W at 1W intervals. An upgrade option is available for 150W RF power.

Tergeo has two mass flow controller (MFC) regulated gas inputs, a third is available as an option. The standard mode of operation is immersion (direct) where the plasma is generated the main chamber. There is also the option of downstream (indirect) mode where the plasma is generated in separate chamber attached to the main chamber – please see below for details.

Tergeo benefits from unique plasma sensing technology which ensures repeatable and consistent results (see below).

Unique plasma sensing technology

A key advantage of the Tergeo series is the integrated, patent-pending plasma sensor technology. The RF plasma strength is measured quantitatively and displayed in real time on the LCD touch screen controller. The operator can use the plasma strength data as feedback to adjust gas flow rates and RF power to give desired plasma cleaning speeds – ensuring repeatable and consistent results for users with beginner or expert levels of experience

Pulsed RF cleaning mode – for gentler, damage-free plasma cleaning

In pulsed operation (option PIE-TG104) more gentle RF plasma reaction rates can be maintained, despite a lower more “specimen friendly” average power.

Using pulsed operation at 480Hz the Tergeo can reduce “dust” particle formation, trenching, notching and charging. For fluorocarbon PECVD processes the use of pulsed operation can yield rougher surface structure and thereby give greater hydrophobicity

Immersion (direct) and optional downstream (indirect) processing

Tergeo has the capability of two integrated RF plasma sources in one instrument – an immersion source plus the option of a remote downstream source (PIE-TG102). When the plasma is generated inside the main specimen chamber, the immersion mode subjects specimens to both energetic ion bombardment and chemical reactions with neutral radical species. Immersion mode processing is required for high-speed plasma etching, plasma ashing and surface modification.

Pumping requirements

Tergeo requires a primary vacuum pump. The Edwards nXDS6i scroll pump is recommended when oil-based pumps need to be avoided (i.e. dry pumping). We also offer standard oil-based rotary pumps including a Fomblinised version for applications where high throughputs of oxygen are required.

Please see Ordering Information for details of pumps and accessories

For other instruments in the Tergeo range of plasma cleaners please see here: Tergeo.

PIE-TG101. Upgrade RF power from 75W to 150W ( 13.56MHz, auto matching)
PIE-TG102. Integrated remote plasma source for downstream cleaning mode for 2D materials, fragile and delicate specimens
PIE-TG103. Third MFC regulated gas input
PIE-TG104. Pulsed mode plasma for generating controlled extremely weak plasmas and for better control of plasma intensity
A73501983. Edwards nXDS6i dry scroll pump. Ultimate pressure 15~50mTorr, speed:6.2 m3h-1
A73601983. Edwards nXDS10i dry pump. Ultimate pressure 5~20mTorr, speed:12.7m3h-1
A50597000. Silencer for nXDS and XDS5/10
C10514297. NW25 braided flexible pipeline stainless steel 1000mm
PIE-A120. Dust particle filter for using room air as a process gas and/or venting the chamber
PIE-A121. Adjustable external venting flow rate control valve (reduce the venting gas flow rate to prevent the light or powder specimens from being blown away)

Typical applications include:

Photoresist plasma ashing, descum and silicon wafer cleaning
PDMS bonding, microfluidics, glass slides and lab-on-a-chip
SEM/TEM specimen cleaning for hydrocarbon contamination removal
Medical device activation, sterilization and improved coating adhesion
Wire bonding, flip-chip underfill, device encapsulation and decapsulation
Improve bonding of metal-to-metal devices and composites
Improve bonding of plastics, polymers and composite materials
Processes requiring a water vapour plasma (using optional PIE-A122 water vapour delivery kit)
A wide range of other plasma etching and plasma ashing applications

Tergeo tabletop RF plasma cleaner, plasma etcher, plasma asher, consisting of:

Thick-wall (5mm) quartz tube ID: 110mm and OD: 120mm, depth 280mm
Direct (immersion) RF plasma source. Optional downstream (remote) plasma source (PIE-TG102)
Plasma emission sensor for quantitative plasma emission intensity measurement
75Watt 13.56MHz high frequency RF supply. Adjustable from 1 to 75W at 1W intervals.
Optional power upgrade to 150W RF supply (PIE-TG101)
Auto-tuning of immersion plasma source
Continuous (CW) Duty ratio can change from 1/255 to /255 (CW). Optional pulsed plasma (PIE-TG104)
7-inch resistive LCD industrial touchscreen controller
Fully automatic operation with 20 recipe support
Job sequence mode operation for three cleaning steps
Two mass flow controllers (MFC) regulated gas inputs. Optional third MFC (PIE-TG103)
Premium pressure sensor from MKS Instruments (1E-4Torr to atm)
Venting/purging port with electronic solenoid valve (Swagelock 1/4″ compression fitting)
One pumping port with electronic shut-off valve and standard NW/KF25 vacuum port

Note: vacuum pump required (see Pumping Options)

Definition of an RF plasma

A radio frequency (RF) plasma is an ionised gas phase substance that consists of ions, electrons, and neutral atoms and/or molecules that grossly maintain charge neutrality. Electrons and ions should be close enough so that each of them can influence many nearby charged particles within a radius called the Debye screening length. As a result, charged particles in the RF plasma respond collectively to external electromagnetic fields. With a high density of free-moving ions and electrons, plasma is highly electrically conductive. With the exception of boundary regions between the plasma and electrodes, a plasma contains the same amount of positive and negative charges. There is no space charge within the bulk of the plasma.

Plasma sheath

Electron temperature is usually equal to or higher than that of ions. Since electrons are much lighter than ions, they can escape from a plasma at a much faster speed than ions, providing there is no confining potential barrier. Once electrons are nearly depleted from the boundary interface between the plasma and electrodes or specimen, a region with only positive ions and neutrals will be formed. This usually dark boundary region is called plasma sheath. Positive charges in the plasma sheath can push more ions to diffuse out of the plasma. It also creates a potential barrier to prevent electrons from diffusing out of the plasma. Eventually, the loss rate of electrons and ions will reach an equilibrium state. The plasma sheath also creates a positive plasma potential with respect to the grounded chamber walls. The voltage drop across the plasma sheath can accelerate ions and create an ion sputtering effect in many applications.

How an RF plasma is generated

Electrons and ions in plasmas can disappear through diffusion or recombination. To sustain a stable RF plasma, external excitation is required to create more electrons and ions so that their creation rate can reach a balance with the loss rate. Most RF plasma generation methods rely on heating free electrons to high enough energy to break down neutral atoms or molecules into ions and electrons.

PIE Scientific specialise in developing advanced plasma systems for plasma etching, cleaning, surface treatment, ion and electron beam production applications. The company was founded by alumni of the Plasma and Ion Source Technology group in the Lawrence Berkeley National Laboratory. After 15 years of experience in developing advanced semiconductor capital equipment in Silicon Valley, they realized that many existing low-cost plasma cleaners and plasma treatment systems were still using decades-old technology. Therefore, they decided to bring state-of-the-art plasma technology developed for the semiconductor industry and nuclear research into affordable plasma instruments. Their SmartClean™ technology has been well-received by customers.

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