Quasi Static Testing - PowerPoint PPT Presentation

Loading...

PPT – Quasi Static Testing PowerPoint presentation | free to download - id: 3e0d69-N2Q3Y



Loading


The Adobe Flash plugin is needed to view this content

Get the plugin now

View by Category
About This Presentation
Title:

Quasi Static Testing

Description:

Quasi Static Testing Advanced Quasi-Static Testing Technology and Applications Henry Patland 2192 Bering Drive San Jose, CA 95131 hpatland_at_us-isi.com – PowerPoint PPT presentation

Number of Views:110
Avg rating:3.0/5.0
Slides: 38
Provided by: usisiComP
Learn more at: http://us-isi.com
Category:

less

Write a Comment
User Comments (0)
Transcript and Presenter's Notes

Title: Quasi Static Testing


1
Quasi Static Testing
  • Advanced Quasi-Static Testing Technology and
    Applications

Henry Patland 2192 Bering Drive San Jose, CA
95131 hpatland_at_us-isi.com www.us-isi.com
2
Topics
  • Introduction to Quasi-Static Testing
  • Advanced Quasi-Static Testing Technology
  • Quasi-Static Testing Applications

3
QST Testing as a Concept
Quasi Static Testing can characterize the GMR/TMR
performance, with the following advantages over
DET Testing
  • Independent of external influence (disk/flying
    height variation)
  • Significantly more flexible, with the ability to
    subject the GMR/TMR to any variety of ambient
    conditions.
  • Can analyze pure GMR/TMR performance with higher
    resolution than DET Testing.
  • Reduced Risk of Handling or Tester damaging heads
  • QST Testing is inexpensive, fast, relatively
    simple, and requires significantly lower
    maintenance and operating costs.

4
Basics of Quasi-Static Testing
The roots of QST are derived from actual drive
operation As GMR/TMR passes over a disk it is
introduced to a variety of magnetic field. In
simplest terms the resistance of the GMR/TMR is
dependent on the magnetic field applied to it. In
ideal case the relationship of GMR/TMR resistance
to applied field is linear, but we dont live in
ideal world.
Close To Ideal Transfer Curve
5
Transverse Transfer Curve
Resistance Amplitude Asymmetry Barkh Jump Hysteresis Bias Point Delta R/R Bias Angle Slope Max Slope
Parametrics extracted from QST Transfer Curve
6
DC Measurements
  • Measures head resistance change versus an
    externally applied magnetic field through a low
    frequency channel. The following DC tests can be
    performed.
  • Transfer curve
  • Stability
  • Bias angle
  • Asymmetry sweep
  • Resistance delta
  • Quasi-Static test

7
Static Tests (HSA / HDA)
  • Verification of the Preamp Chip, Flex, and Voice
    Coil assembly can be performed.
  • Voice coil measurements
  • Fault detection
  • Current consumption
  • Pin-Pin and Pin-Ground shorts
  • Temperature Sensor control
  • Passive component measurements
  • RDX / RDY offset voltage

8
AC Measurements
  • Measures high frequency noise as influenced by
    write excitation, field excitation, or
    combinations of both. The following AC tests can
    be performed
  • Popcorn Noise
  • W/R Recovery
  • Field Induced Noise Characterization
  • Frequency Response

9
AC Channel Technology
  • Glitch After Write (Popcorn)
  • Field Induced Instabilities (Noise)
  • Spectral Analysis (FFT)
  • 200 Mhz Analog Bandwidth
  • 160 Mhz 10-bit digitizer
  • Low Noise
  • W/R Recovery lt 500 ns
  • 400 Mhz Write Frequency

10
Write Induced Instabilities
Writer Induced Instabilities (Popcorn)
11
Field Induced Instability
Soft Kink at 160 Oe
12
Field Induced Instability _at_ 150 Oe
13
Field Induced Instability _at_160 Oe
14
Field Induced Instability _at_ 170 Oe
15
Spectral Maximum Amplitude Noise
  • Noise RMS (uV)
  • Noise Amp (uV)
  • Max Noise Amp (uV)

S.M.A.N
16
Digitizer is The Key to S.M.A.N.
  • Qualifies Three Types of Instability Events in
    One Shot
  • RMS Noise for broadband noise
  • Max Amp for rare events such as Barkh. Jumps and
    Write Induced Instability
  • Amp Noise for high probability noise

17
Transfer Curve S.M.A.N.
Soft Kink and Max Noise at 160 Oe
18
Applications for QST Testing
  • Bar, Slider Testing
  • HGA, HSA, HDA Testing
  • ESD Tolerance Testing
  • Thermal Reliability Testing

19
Row/Slider Level Testing
20
Benefits of Row/Slider Testing
  • Early look at Wafer process for QST Parametrics
    and Instability
  • Upstream testing reduces scrap cost
  • Bar to 4000 Sliders/Hour
  • Slider to 1200 Sliders/Hour

21
HGA, HSA, HDA Level Testing
  • HGA
  • HSA
  • HDA

22
Benefits of HGA, HSA, HDA Testing
  • Process Control
  • Simple Test/Tooling
  • Failure Analysis at HDA level
  • HSA Screening Prior to Drive Build
  • HDA Screening After Servo Write

23
ESD Tolerance Measurement And Process Mapping
  • ESD Tolerance Repetitive Inject and Test HBM,
    MM and DCDM
  • CDM (Charged Device Model) is rapidly becoming
    the standard for characterizing GMR/TMR head ESD
    Failure Thresholds
  • Process Mapping Test After Each Process
    Including Bar, Slider, HGA (Before/After DET),
    HSA Prior to Final Bond and HDA After Merge and
    After Servo Write
  • Symptoms First Failure Mode Instability, then
    Parametrics

24
CDM Tolerance Characterization
D-CDM Cartridge Assembly
ESD/CDM Pulse System
25
QST can characterize ESD damage by applying
controlled ESD events to GMR head
  • HBM
  • CDM

26
What can be done about GMR/TMR head ESD
Sensitivity ?
  • Improved design of GMR/TMR head which is less
    sensitive to ESD
  • Eliminate ESD events from Manufacturing
  • Monitor GMR/TMR head performance after every
    significant process to isolate and eliminate ESD
    events in Manufacturing

As Al Wallash Maxtor would put it Dont loose
your head over ESD
Whatever you do, QST Testing can Help!
27
By Applying Varying Amplitude ESD Events to GMR
Head, QST can easily determine heads Failure
points
Resistance Failure Meltdown
Amp Failure Pin Reversal
Asymmetry Failure
28
DCDM Sweep
CDM Failure Threshold at 3.5V 25 lower than Amp
Failure at 5V
29
Thermal Reliability Testing
  • Accelerated Life Testing at Row Level
  • Accelerated Life Testing at HGA Level

30
Accelerated Life Testing at Row Level
31
Accelerated Life Test _at_ 5.5 Days
Resistance and Amplitude Deteriorating after 5.5
Days of elevated temperature (100C) and elevated
VBias
32
HGA Level Accelerated Life Test
Up to 8 simultaneous HGA testing
33
Parametrics vs. Temperature
Temperature Test
Transfer Curve
34
Benefits of Thermal Reliability Testing
  • Accelerated Life Testing Can Predict Failures
    Before They Occur
  • Row Level Testing Provides Early Look at Thermal
    Reliability

35
Conclusion
Dont loose your head over ESD, Instability or
Reliability
Whatever you do, QST Testing can Help!
36
References
1 J.Himle, R.Cross, M.Greenwell, Drive-Level
Instabilities Correlated to Quasi-Static Field
Testing, MMM-Intermag 2001 2 C. Moore, A
Comparison of Quasi-Static Characteristics and
Failure Signatures of GMR Heads subjected to CDM
and HBM ESD Events 3 H. Patland, W. Ogle,
High Frequency Instabilities in GMR Heads Due to
Metal-To-Metal Contact ESD Transients, EOS/ESD
Symposium 2002 4 Integral Solutions Intl,
Quasi 97 and QST-2002 Tester
37
Acknowledgements
  • Al Wallash Maxtor
  • Mark Nichols Maxtor
About PowerShow.com