Bat find its way around by
emitting short ultrasonic pulses and it
detects reflected echoes from obstacles
along its flight path.
Similarly, SAM utilizes
ultrasonic frequencies up to 2GHz to detect
acoustic impedence changes in bulk material,
layer transitions or interfaces of opaque
specimens. The non-destructively detected
echoes can be any of the defects or
structures of interest in schematic below:
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Key Features
Highest resolution available with a
worldwide unique frequency spectrum up to 2000MHz which is
comparable to high resolution optical microscopy, 0.3µm
= λ/2.
Nondestructive and fast examination
of volume and structural defects in different materials.
Displaying of non-homogeneities,
density, differences, tensions, delaminations.
Layer-thickness measurements,
reliability examination, judgment of material connections.
The confocal properties can be
exploited to give enhanced depth discrimination to examine
individual interfaces.
Simple operation with Windows
graphical user interface and integrated process automation.
Flexible application through
different scan modes and variety of different transducers.
Modular concept and product platform
strategy on all SAM products to increase uptime and reduce cost
of ownership.
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The Operation principle
The Scanning Acoustic Microscope operates
with the pulse reflection method. The special acoustic
objective-centerpiece of the microscope, produces, transmits
and receives short sound pulses of high penetration rate.
The acoustic lens converts high frequency electromagnetic
vibrations which are propagated as a plane parallel wave
field inside the lens. The cavity focuses the sound field on
the sample through the coupling medium (water). The acoustic
lens receives the sound pulses reflected from the sample.
The transducer transforms the sound pulses
into electromagnetic pulses which are displayed as pixels
with defined gray values. To produce an image the acoustic
objective scans the sample line by line. A transducer with
good focusing properties on axis can be used for both
transmitting and receiving the signal. The image is formed
by scanning the transducer mechanically over the sample.
Transmission of the
sound pulses into the sample and reception of sound pulses
Attainable
imaging resolution depending of the working frequency of the
transducer Specimen: Bone. By courtesy of Dr. Raum,
University of Halle, Germany
SAM TEC acoustic microscopes provide
the largest frequency range for non-destructive ultrasonic testing. For routine use 2000MHz is the highest practical frequency,
which offers a resolution of about 0.3 µm.
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COMPONENTS
* 3-50 MHz Transducer * 100-400 MHz Acoustic objectives * 800-200 MHz ultra high frequency acoustic objectives
Transducers
High resolution transducer up to 2000 MHz The frequency of 2000 MHz is the worldwide
highest practical frequency supplied by SAM TEC for acoustic imaging
and analysis, which offers resolution values down to 0,3 µm.
SAM TEC provides transducers from 800 - 2000 MHz for different high
resolution applications.
There are many situations where for thin coating layers the
measurement of the elastic properties of the layer structure could
be important to understand the properties of coating processes.
Even more desirable in some applications is knowledge of stresses in
the layer. It is now possible to make measurements by quantitative
acoustic microscopy that will yield this kind of information.
Accurate elastic measurements by acoustic microscopy were pioneered
using cylindrical lenses which brought the acoustic beam to a focus
along a line. This means that Rayleigh waves were excited in the
surface of the material in one azimuthal direction in the surface
only, so that even if the sample was anisotropic only one Rayleigh
velocity would be involved. Line-focus-beam lenses give particularly
well defined oscillations in the variation of signal with defocus -
the so-called V(z) curve - and by suitable Fourier analysis surface
wave velocities can be determined from the period of the
oscillations with an accuracy which can exceed 0.1 %. The
attenuation of surface waves can also be measured.
Electronics
Stages
Scanning systems
designed for a broad application range
Scanning speed:
Up to 1 m/sec Stepper motor controlled scanning system with a x-y range 100mm x 100mm
Scanning speed: Up to
1m/sec Linear servo scanner stage with a x-y range of 320 mm x 300 mm
Scanning speed: Up to
1m/sec Air support direct drive motion system for high throughput
acoustic analysis, maintenance free. 400 mm x 400 mm XY Scan range.
Software
Software
functions for non-destructive defect and failure analysis
- Visualisation
Dedicated non destructiveimaging and analysis of structures inside any bulk
specimen
3D reconstruction
Display of mechanical properties of sample
(hardness, density, stress, etc.)
Time of flight measurement (A-scan)
Cross-section images (B-scan)
XY images: C-scan, D-scan, autoscan,
multiscan
- Quantification
Fault statistics
Histogram analysis
Integrated measurement functions
Film thickness measurement
Multifunctional image processing
Time of flight measurements
Non-destructive depth measurement
Digital signal analysis
Phase measurements
Defect maps including result files
- Automation
Automatic X-Y-Z-scan and storage ofall instrument parameters
Automatic fault recognition
Autofocus-system
Remote control
Fast auto sample detection
Auto gate and gain control
Auto signal analysis
Auto loader system integration
SECS interface
Integration of bar code readers
Auto alignment
High speed robot for wafer up to 12 inch
including cassette load stations
Automation
Customized automated
solutions for inline process diagnostic and control
Inline inspection from 2" - 12“
Clean
room compatibility down to class 10
Integrated data analysis and
automation software, fab communication by SECS
interface
Twin Scanner for highest throughput
Arrays of 2 or more transducers for
simultaneous image acquisition
Fast data acquisition by master/slave
computer configuration, enabling of transducer
arrays formaximum
throughput
Wafer inspection
station for wafer handling in water
High speed robot for wafers up to 200
mm
Pre-aligner and bar code reader
Twin scanner with two transducers
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Frequency and Wavelength
Frequency ranges with the attainable imaging resolution and applications
referred to the respective resolving power attainable within this
frequency range.
