The Wafer Profiler CVP21 has a large amount of benefits over other ECV-Profiling equipment:
1. Benefits concerning the application range
2. Benefits concerning the installation
3. Benefits concerning the operation
4. Benefits concerning the software
5. Benefits concerning the N measurement
6. Benefits concerning the etching/ Fluid system
1. Benefits concerning the application range:
Ready to measure n and p (Al,In)GaN or AlInN due to an etch algorithm that produces mirror like etching at reasonable etch rates of typically 2microns/h (Option WB).
Ready to measure Silicon (Si) due to its ability to handle electrolytes containing Fluorides.
Extended measurement range due to the high precision of the electronics (below 1012 cm-3 to above 1021 cm-3)
Ready to measure complete wafers up to 8 inch diameter.
Ready to measure small samples due to a very flexible wafer chuck and easy visual control of the contacted sealing lid peripheral.
Ready to measure through pn junctions and otherwise complicated layer interfaces due to the automatic adaptation of the evaluation voltage.
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2. Benefits concerning the installation:
Ready to be installed without the need of a chemical bench beneath: Chemical waste bin, basin and exhaust connection are included.
Ready to varying user preferences: To be used either as desktop equipment or including its own floor standing bottom with 60cm wide and 80cm deep footprint (option FP, clean room ready shielded by polished stainless steel).
Ready for clean room installation with an enclosure made of polished stainless steel and an acrylic front.
Ready for future operating systems: It uses a standard Windows TM PC (communications via standard RS232 and USB 2.0).
Easy serviceable due to a clear mechanical separation of the fluid part, the optical part and the electronics, and due to the modular design of the electronics in a 19" rack.
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3. Benefits concerning the operation:
Full automatic “Dry in – Dry out“ processing of samples.
Easy change of the newly designed sealing ring.
Ready to deliver operator independent results: The electrochemical cell with the precision sealing ring lid is driven gently to the semiconductor surface, until the predefined pressing force is reached. The surface of the semiconductor is sensed automatically, so the force does not depend on the thickness of the semiconductor sample.
Full automatic loading of the cell with electrolyte.
Reliable debubbling of the semiconductor electrolyte interface. It is neither necessary nor recommended to add any further chemicals to reduce the surface tension of the fluids.
Full automatic changing of the electrolyte is possible during the measurement process.
The cell may be unloaded automatically, including an automatic washing of the complete fluid system.
Ready to run stand alone: A high resolution color camera delivers an optical image of the semiconductor electrolyte interface to the PC screen (option OI).
Ready to measure wafers automatically: Wafer stepping capabilities (option WX, WT).
Ready to measure the complete range of semiconductors: Software selection between dimmable Halogen lamp and wide bandgap ready UV lamp (Option WB).
Automatic reliability checking of the measurement result: The results include error bars for each measurement point.
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4. Benefits concerning the software:
Ready to be used by standard users: The measurement recipe for a sample type contains the complete measurement parameters.
Strong help support for the operator: The state of the art Windows TM help system includes valuable hints concerning the profiling of complicated materials and layer combinations.
Strong support for the operator by either full automatic, semi automatic or manual measurement modes.
Strong protection of the operator by varying priority levels concerning parameter access.
Strong support for the operator by clear placement of the relevant parameters in each measurement window.
Continuous on-line storage of the current process to the hard disk. Thus it is no problem to continue a process that has been stopped by some accident.
Strong support of reliability checking and error analysis of the measurements: The software includes wealthy tools for recalculation and error analysis. The measurements are delivered with error bars.
Good interconnectivity, data and measurement files may be exported to CSV, HTML, EMF, ready e. g. for Excel TM, Word TM, Internet publishing.
Easy remote control: The system may be operated from remote network locations.
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5. Benefits concerning the N measurement:
Fully digitized electronics eliminates AC calibration needs. The DC electronics is calibrated and the AC electronics is checked automatically during the self test.
Measurement of capacitance values either with 2 frequencies, to evaluate the complete 3 component equivalent circuit, or alternatively also with a 3rd frequency to evaluate the 3 component equivalent circuit including error analysis.
Reliable signals also for samples with very low doping due to Coax cabling up to the electrochemical cell and the semiconductor.
Reliability checking of the Schottky behavior of the electrolyte semiconductor interface at every measurement point, thus the measurement result is delivered with error specification.
The optimum voltage point for the evaluation voltage may be selected by the software automatically, thus the etching through pn junctions and many complicated interfaces is straight forward.
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6. Benefits concerning the etching/ Fluid system:
High quality Teflon TM/ PTFE is used to machine the electrochemical cell and the valves. Thus these key components are utmost resistant against any chemicals. Particularly the system is ready to be operated with electrolytes containing Fluorides.
The main features of the proven traditional cell design have been kept. This cell design delivered good ECV etch results over more than 20 years with a tremendous number of different semiconductor layer combinations. The geometry of the current distribution in the cell and the positioning of the electrodes are utmost important for clean and homogeneous etching.
The electrochemical cell is produced without any soldering, thus no corrosion is possible to happen at the electrochemical cell.
The debubbling procedure works reliable. Thus it is neither necessary nor recommended to use any "soap" additives for the electrolyte or cleaning liquids. Furthermore it is possible to run etch procedures which apply fresh electrolyte in a continuous or repetitive manner.
The N evaluation voltage may adapt automatically to differing semiconductor surfaces, thus the etching through pn junctions and many complicated interfaces is straight forward.
The washing of the complete fluid system including the electrochemical cell is performed automatically.
The complete fluid system is attached to the front side of the equipment. Thus if the acrylic front hoods are opened, the complete fluid system is easily overlooked. Especially the peripheral of the contacted sealing ring may be easily checked, as the acrylic front hoods may be opened during the etch process. This also is very important for samples which are so small, that they are at the limit to be measured (thus having dimensions of only few mm˛).
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