1. The Langmuir Probe Product Overview

2. Langmuir Probe System The Langmuir Probe System is a precision plasma measurement instrument usedin a wide range of plasma laboratory applications. It is the key instrument used byscientists to measure the internal parameters of the bulk of the plasma. Among the key parameters measured are electron density, Ion density, electrontemperature, plasma potential, floating potential and the electron energydistribution function (EEDF). The Langmuir Probe System provides plasmaparameter measurement in DC, RF, Microwave, Continuous and Pulsed plasma.Overview 3. The Langmuir Probe System The Impedans Langmuir Probe System has the most advanced technology on themarket and analyses ion and electron trajectories to obtain accuratemeasurements of the real plasma parameters in a wide range of plasmaapplications. The Impedans Langmuir Probe System is the fastest and most reliable Langmuirprobe in the world (time resolution 12.5ns). In addition to speed and reliabilitythe Impedans Langmuir Probe System provides the most advanced and trusted,fully automated data analysis in real time.Overview 4. Customers Requirements As substrates become larger, and featuresizes smaller, there is an increasing demandfor tighter control of the plasma process. Measurement of the bulk plasmaparameters such as the electrontemperature and the plasma density arecrucial for model predictions of theconditions at the substrate surface.Motivation 5. Specifications Traditionally Langmuir Probes where limited in their application but Impedanshave broken the mould and designed Langmuir Probes to work in the mostextreme environments. Atmospheric Pressure Thermal Plasmas Insulating Deposition PlasmasDesign 6. Features High temperature ceramic coated shaft is connected to the external data acquisitionunit through a vacuum feed-through, which is mounted at the reactor wall, andenables the probe to operate up to 1200o Celsius. Replaceable tips and tip holder sensing elements is a convenient feature for theuser, especially when operating in deposition systems. The standard system uses a10mm tip, there is also a custom tips available for off standard applications.Design 7. The Basic StructureThe figures below show the Langmuir probe systems bias configurations. Thesingle probe is used in well grounded reactors while the double probe is moresuited to reactors with poor ground return i.e. reactors with dielectric walls.Theory of Operation 8. The Single Probe Circuitry A conductive probe tip exposed to the plasma isbiased with a potential sweep (V) spanningboth negative and positive potentials. The current (A) collected by the probe tip fromthe plasma flows through the circuitry and isrecorded. The voltage at the probe tip is measuredprecisely (V). The voltage drawn from the plasma by theprobe tip is returned to plasma through theground return.Theory of Operation 9. The Double Probe Circuitry The two probe tips exposed to theplasma are biased, with respect toeach other, using a potential sweep(V) spanning negative to positivepotentials. The current (A) circulating betweenthe probes is recoded. The voltage between the two probetips is measured precisely (V). The current collected by each probeis returned to the plasma throughthe other eliminating the need fora ground return.Theory of Operation 10. Current Voltage Characteristic A typical VI CharacteristicSingle Probe A Typical VI CharacteristicDouble ProbeTypical Results 11. Semion System on a Lam Research Chamber A typical Langmuir Single Probe System installation is shown in figure 2. TheProbe was mounted in the mid-plane of an Oxford Instruments capacitivelycoupled plasma reactor. The substrate holder was driven with 13.56MHz RFpower to ignite the discharge. The working gas was pure Argon at a pressure of10 mTorr. EEDFs were measured for a range of RF power levels applied to thesubstrate holder. Figure 2: Langmuir Single Probe System installation in an Oxford Instruments CCP reactor.Typical Results 12. EEDF Variation as a Function of RF Power Figure 4: shows how the EEDF variation as a function of RF power applied to the substrate holderwhile the pressure is maintained at 10 mTorr throughout.Typical Results 13. The Langmuir Single ProbeProducts 14. The Langmuir Double ProbeProducts 15. The Langmuir AtmospheriX ProbeProducts 16. The Langmuir Plato ProbeProducts 17. Our Systems Measure PlasmaHelping You to Understand Your ProcessesAllowing You to ControlThank You for Your TimeQuestions