ICAM

USL Ultrasonic Sciences Ltd

ICAM scanning acoustic microscope

High speed scanning with low vibration
Multiple images produced simultaneously
Mobile system, easily moved around the plant

The ICAM scanning acoustic microscope is a high speed, fully digital and integrated system designed for rapid non-destructive inspection of integrated circuit (IC) packages and similar parts. It can be used in development, production and failure analysis situations to give repeatable and detailed information on internal features, showing the presence of manufacturing, processing and in-service defects.

Ultrasonic Sciences has been designing and building digital ultrasonic testing systems for more than 13 years and the ICAM is the product of this combined expertise in mechanical, electronic and software design. Because it incorporates full digital control of all parts of the system, it is simple to operate for repetitive tasks, requiring the minimum of operator skill. At the same time, it has the flexibility to offer very detailed analysis when the situation demands.

Because of its advanced mechanical and data acquisition design, ICAM can inspect IC packages at very high speeds whilst generating real time, high resolution images. Typically for a 25 x 25mm scan area, a speed of up to 15lines per second is achieved - this means that a 250 x 250 pixel scan image can be produced in about 20 seconds. Images at lower resolution can be produced in even less time.

The basic ICAM system is a completely integrated unit, comprising a purpose designed mechanical scanning stage and computer based ultrasonic and data acquisition electronics. A range of high frequency transducers is included, together with a colour printer for hard copy of scan images. The mechanical scanning system is an inherently low vibration unit and does not require a bulky base assembly or heavily damped mountings. This makes it compact and mobile, so that it can be easily moved to different locations in the plant when required.

ICAM SPECIFICATION

PHYSICAL
Overall dimensions	Scanner / electronics 600 x 600 x 1500 mms
Weight	Scanner / electronics 260kgs
Power supply	110 / 220 / 240V, single phase

MECHANICAL
Scan area	350 x 250 mms (X, Y)
Z axis motion	50 mms (Vertical motion of table)
Tank size	380 x 290 x 50 mms
Resolution	0.005 mm on all axes
Repeatability	Better than 0.01mm
Drive - X axis	Balanced drive by DC servo and steel tape, with precision linear optical encoder (Renishaw)
Drive - Y axis	Twin precision ballscrew on linear slides, with DC servo motor and rotary optical encoder
Drive - Z axis	Ballscrew on linear slide, with DC servo motor and rotary optical encoder.
Acceleration - X axis	5 metres / sec / sec
Scan speed	Instantaneous speed up to 3 metres/sec. On a 25 x 25 mm scan a reciprocating speed of 15 lines/sec can be achieved.
Scanner control	Automatic - under software control according to scan size and index. Manual - joystick operation with position display
Through transmission adaptor	Sample table and transducer yoke fixture.

COMPUTER
Type	Industrial 19" rack mount
CPU	Pentium, clock speed 1.2GHz
RAM	256 Mbytes
HDU	40 Gbytes minimum
FDU	1.44Mbyte, 3.4"
Storage	Rewriteable CD drive
Graphics	SVGA, 1024 x 768 x 256 colour
Monitor	17"

ULTRASONIC AND DATA ACQUISITION
Type	PC expansion boards
Pulser Receivers
Type	PR20 and PR50 types as standard
Pulse voltage	600V maximum (Normal operating maximum for 25 / 50 / 75MHz transducers is 300V.
Pulse type	PR50 spike pulser, PR20 square wave pulser
Pulse width	PR50 - 5 nanosecs max, PR20 variable 30 - 120 nanosecs
Pulse rise time	PR50 - <5 nanosecs, PR20 - 15 nanosecs
PRF	5kHz maximum
Bandwidth	Preamp 1 - 75MHz (-3dB), Main amp 1 - 50MHz (-3dB)
Gain	74dB
Attenuation range	63dB
Filters	5 low pass filters
Control	Direct software control
A-D converter
Type	USL ADC100
Sampling rate	100msps single shot, >8GHz for repetitive signals
Resolution	8 bit
Features	Programmable delay and sampling rate, automatically selected according to delay and timebase set on A scan display.
Data Bus	High speed databus to DSP board

Data acquisition
Source	USL DSP100 digital signal processor
Speed	500Mips. Processing of up to 5000 waveforms per second.
No of gates	8 simultaneous gates
Gate modes	Positive amplitude Negative amplitude Time of flight Phase
Trigger modes	Main bang trigger Interface trigger (surface follower)
Trigger threshold	Positive edge or negative edge, adjustable threshold 0 - 100%
Gate resolution - time Gate resolution - amplitude	10 nanosecs 8 bit (256 levels)
Phase detection (delam gate)	Detects polarity of signal as first crossing of the preset threshold (positive going or negative going). Variable threshold 0 - 100%.

Motion control and I/O
Source	USL Master System Controller and PMAC boards
Inputs	Encoders and limit switches for X, Y and Z axes.

TRANSDUCERS
Types (standard system)	50MHz, 0.5" focus polymer transducer 25MHz, 1" focus polymer transducer 25MHz polymer transducer in TT yoke

SOFTWARE
A scan display	Digital display, update rate 25Hz. Variable delay and timebase
A scan display mode	1) Moves with Z axis motion 2) Delay locked to Z position
A scan tools	A scan cursor measurements, amplitude, time, frequency
Inspection modes	Pulse echo and through transmission
Scan modes	C scan, Trayscan (Step and Repeat), Volume Scan (Full RF acquisition and processing)
Scan area	Any value of X and Y axes up to 350 x 250 mm
Pixel points	Fully operator selectable from 0.01 x 0.01mm
Gate selection	Main bang or interface trigger Amplitude or phase or time Select gate type / image display type
Motion options	Move to home Move to zero Find centre of package Step and repeat
Real time image display	Up to 8 simultaneous real time scan images Current position displayed by cursor

Image processing	Colour palette selection and editing (special user edited palettes) Separate palettes for positive amplitude and negative amplitude images Contrast enhancement Convolution (image filters) Zoom. Pan and Scroll Histogram area measurement in selected area - live update On screen measurement
Volume Scan (RF processing)	Live RF display from stored data Multiple C scan image display Scrolling B scan image display Access to all normal image processing functions
Printing	Print of operator selected area
Image format	.BMP images (Compatible with Word, Paintbrush, Publisher etc)

Typical scan images from the ICAM, clockwise from top left:
1. "Phase" image showing delamination areas in red.
2. Image of TQFP showing small areas of delamination (white) on the leadframe and small voids in the mold compound indicated by "shadow" effects.
3. "Phase" image of 3 QFP's showing variations in adhesion of the mold compound to the diepad.
4. Through transmission image of BGA showing "popcorn" defect.

A high frequency version of the ICAM is also available. This uses the same high precision scanning unit as the standard ICAM, but new ultrasonic and data acquisition units are incorporated, including a 400MHz Pulser Receiver and a 500MHz analog-digital converter. This provides a capability for ultrasonic testing at frequencies up to 250MHz. The main applications are in advanced IC manufacturing and packaging, such as flip chips and bonded wafers.

ICAM scanning acoustic microscope

High speed scanning with low vibration

Multiple images produced simultaneously

Mobile system, easily moved around the plant