Advanced Bode Plot Techniques for Ultrasonic Transducers

Physics Procedia 63 ( 2015 ) 2 – 10

Available online at www.sciencedirect.com

1875-3892 © 2015 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).Peer-review under responsibility of the Ultrasonic Industry Associationdoi: 10.1016/j.phpro.2015.03.002

ScienceDirect

43rd Annual Symposium of the Ultrasonic Industry Association, UIA Symposium 2014

Advanced bode plot techniques for ultrasonic transducers

D. A. DeAngelis and G. W. Schulze Mechanical Engineering, Ultrasonics Group, Kulicke & Soffa Industries, 1005 Virginia Drive, Fort Washington, PA 19034, USA

Abstract

The Bode plot, displayed as either impedance or admittance versus frequency, is the most basic test used by ultrasonic transducer designers. With simplicity and ease-of-use, Bode plots are ideal for baseline comparisons such as spacing of parasitic modes or impedance, but quite often the subtleties that manifest as poor process control are hard to interpret or are nonexistence. In-process testing of transducers is time consuming for quantifying statistical aberrations, and assessments made indirectly via the workpiece are difficult. This research investigates the use of advanced Bode plot techniques to compare ultrasonic transducers with known “good” and known “bad” process performance, with the goal of a-priori process assessment. These advanced techniques expand from the basic constant voltage versus frequency sweep to include constant current and constant velocity interrogated locally on transducer or tool; they also include up and down directional frequency sweeps to quantify hysteresis effects like jumping and dropping phenomena. The investigation focuses solely on the common PZT8 piezoelectric material used with welding transducers for semiconductor wire bonding. Several metrics are investigated such as impedance, displacement/current gain, velocity/current gain, displacement/voltage gain and velocity/voltage gain. The experimental and theoretical research methods include Bode plots, admittance loops, laser vibrometry and coupled-field finite element analysis. © 2014 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the Ultrasonic Industry Association.

Keywords: Ultrasonic transducer; Wire bonding; Bode plots; Piezoelectric; PZT8; Vibrometer; Coupled-field FEA; ANSYS

1. Introduction

The Bode plot, displayed as impedance or admittance versus frequency, is the most basic test used by ultrasonic transducer designers. With simplicity and ease-of-use, Bode plots are ideal for baseline comparisons such as spacing of parasitic modes and impedance. But, quite often the subtleties that manifest as poor process control are hard to interpret or are nonexistent from standard Bode plots. In-process testing of transducers is time consuming for quantifying statistical aberrations, and assessments made indirectly via the workpiece are difficult for identifying

© 2015 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).Peer-review under responsibility of the Ultrasonic Industry Association

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D.A. DeAngelis and G.W. Schulze / Physics Procedia 63 ( 2015 ) 2 – 10 3

cause and effect relationships. Transducer modal surveys require an expensive scanning laser vibrometer and interpretation is esoteric. Advanced bode plot techniques are needed for a-priori process assessment of ultrasonic transducers.

2. Specific transducer application

Kulicke & Soffa Industries is the leading manufacturer of semiconductor wire bonding equipment. This “back-end” type of equipment provides ultrasonically welded interconnect wires between the wafer level semiconductor circuitry (die) and the mounting package (frame) as shown in Fig. 1. The ultrasonic transducer delivers energy to a capillary tool for welding tiny gold or copper wires, typically on the order of .001 inches in diameter. Fig. 2 shows the primary steps of the wire bond cycle used to produce the interconnect wires, and how the ultrasonic energy from the transducer is delivered in a “scrubbing motion” to make the welded bonds. Fig. 1(d) shows the on-machine configuration. The single-piece construction “Unibody” transducer uses four diced, rectangular PZT8 piezoceramics, and is ideal for research studies (DeAngelis et al., 2006, 2009, 2010). Portability across 100’s of machines is required for the same customer device in production operations.

Fig. 1. (a) K&S “Unibody” ultrasonic transducer, (b) Ceramic capillary tool tip with fine gold wire compared to sewing needle, (c) Actual wire

bonds from multi-tier package, (d) On-machine configuration of “Unibody” transducer during device wire bonding.

Fig 2. Primary steps 1, 2 and 3 of the wire bond cycle

3. Assessment methodology

What aspects of transducer performance are important for ideal process control (Stansfield, 1991, Wilson, 1991, Sherman et al., 2007, Uchino et al., 2003)? The mechanical interfaces must behave linearly in vicinity of the operating mode, such that there is no separation or “gapping” with drive level or frequency change (DeAngelis et al., 2009, 2010); the critical interfaces are tool-to-clamp and the piezoceramic stack. The displacement gain of all surfaces must behave linearly in vicinity of the operating mode and proportional to drive level: the displacement/current gain should be linear in vicinity of resonance, and the displacement/voltage gain should be linear in vicinity of antiresonance (DeAngelis et al., 2006). The tool motions must be consistent in all directions above and below the operating mode: in-plane motions remain in-plane, and linear motions remain linear and in same direction. No local parasitic resonances should be competing with the operating mode; parasitic coupling has a 180° phase change when driven through the operating mode. The usual suspects are shim electrodes, tool clamps, screws and tools. Shim electrode resonances are hard to detect since their manifestation can vary wildly with slight

CapillaryTool

1¢ US

TransducerBody

Piezo Stack

New IConnTransducer

CapillaryDeviceDie

Transducer

On IConn Machine

EFO (Spark)

(a) (b) (c) (d)

4 D.A. DeAngelis and G.W. Schulze / Physics Procedia 63 ( 2015 ) 2 – 10

change of operating frequency. There should be no hysteresis in frequency or displacement gain with sweep direction; the phase lock loop (PLL) can approach arbitrarily from either side, and thus hysteresis can cause phase/amplitude oscillation or failure of PLL to lock at resonance. Interface gapping can change with phase of parasitic coupling above and below operating mode, causing hysteresis in gain and frequency. Internal self-heating effects from impedance are different above and below operating mode due to antiresonance and sweep start direction.

4. Research summary

Advanced Bode plot techniques were developed from the basic constant voltage versus frequency sweep; this included constant current and constant velocity interrogated locally on transducer (Uchino et al., 2003, Ural et al., 2009), with added up and down directional frequency sweeps to quantify hysteresis effects (Umeda et al., 2000). Selected transducers with known “good” and known “bad” process control were studied, and a linear coupled-field FEA model was correlated to the “good” transducer. The advanced Bode plot methodology for a-priori process assessment was established based on these comparisons.

5. Experimental methods and metrics

Fig. 3 shows the hardware setup for the advanced Bode plot technique. Fig. 4 shows the methodology for velocity interrogation. The tool is the “business end” of the transducer and should be a starting point. The tool clamp is a close second for interrogation, since it may exhibit more non-linearities than tool with free-air assessment (i.e., off work). As shown in Fig. 5, the piezoceramic stack should also be another target area, and especially for Langevin or sandwich transducers which are prone to uneven preload stress. High power piezo stacks can rely on adhesives in tension which can fail, and shims and preload bolts are dynamic components that are prone to resonate.

Fig. 3. Advanced Bode plot technique hardware setup.

Fig. 4. Methodology for velocity interrogation.

Laser Vibrometer Polytec OFV 056

USB I/O

Laser BeamTransducer

Network Analyzer HP E5100A

Amp 10:1

Attenuator

Ultrasonics Power Amp 4:1

Function Generator HP 33120A

USB/GPIB Interface Agilent 82357B

100Ω Resistor

Oscilloscope Tektronics DPO7054

PC Command Center(Visual Basic Program)

GPIB I/O

GPIB I/O

GPIB I/O

NA

OS

LV

VB

Vel-in

V-ref

I-inV-out

Four LCD Monitors

LV

NA

OS

Laser Dot

I-Probe

V-Probe

Vel

Top or Tip of Tool in X DirectionTop or Tip of Tool in -Y Direction

(Operating Mode Direction) Tip of Tool in Z Direction

Tool Clamp in -X Direction Piezo Stack in Z Direction

Laser Dot(X-Top) Laser Dot

(Y-Top)

Laser Dot(Z-Tip)

Laser Dot(X-Clamp)

Laser Dot(Z-Stack)

Shim Electrode in -Y Direction

Laser Dot(Y-Shim)

Laser Dot(X-Tip)

Laser Dot(Y-Tip)Y

Z

X

Z

Y

Z

X

Y

X

Y

X

Z


Fig 5. Velocity interrogation target areas for typical transducers.

6. Finite element modeling

Fig. 6 shows the piezoelectric coupled-field finite element model from the ANSYS software with coupling via “stiffness” matrix which includes the piezoelectric properties for PZT8 material. The nodes have structural (X, Y, Z displacements) and electric (volt) degrees of freedom. The linear model was created without interface gapping (i.e., no gap elements) to correlate to the “good” transducer, and a constant damping ratio of 0.2% was used for all materials. The forced response was generated using a sine-sweep voltage input to the piezoceramic stack. Fig. 7 shows the FEA derived Bode results for clamp and top of capillary tool in the X-Clamp, X-Top and Y-Top directions as shown in Fig. 4; there is no hysteresis with the linear model, so results are independent of sweep direction. Fig. 8 shows the FEA derived gain ratio results for these same directions. The current and velocity gains are the same with a FEA linear model.

Fig. 6. Piezoelectric coupled-field finite element model in ANSYS software.

Fig. 7. FEA derived Bode results for clamp and top of capillary.

Preload Bolt

Piezo Stack Driver(Thru Bolted)

Wedge Tool(Long and

Heavy WC)

K&S Orthodyne Large Wire Wedge Bond Transducer(Langevin Style with Bolted Piezo Stack Driver)

K&S Maxum Ultra Transducer(Previous Model Transducer for Ball Bonding)

Piezo Stack

Ceramic Tool

Preload Wedge (3Pc.)

ToolClamp(Set

Screw)

ToolClamp(Split)

Screw

Shim Electrodes

Piezo Ceramics

Green: -Y Poled

Yellow: +Y Poled

Orange: Electrode

X-Top Y-Top

X-Clamp

CapillaryTool


Fig. 8. FEA derived gain ratio results for clamp and top of capillary.

7. Experimental results

Figs. 9-12 show the advanced Bode technique results for the “good” transducer with the expected or “good” process response. As shown in Fig. 4, the velocity interrogation locations are X-Clamp, X-Top and Y-Top. The gain ratio results presented in Fig. 12 are for comparison to the linear FEA model, to demonstrate that a “good” process response is inherently a linear response. Figs. 13-17 show the advanced Bode technique results for the “bad” transducer with poor process response (i.e., inconsistent shears). The velocity interrogation locations are the same as the “good” transducer.

Fig. 9. Constant current Bode for “good” transducer with X-Clamp velocity.

X-Top Y-Top

X-Clamp

CapillaryTool

Constant Current Feedback SF5505-13 IConn

0.00

0.15

0.30

0.45

0.60

0.75

0.90

1.05

1.20

1.35

1.50

1.65

1.80

121700 121800 121900 122000 122100 122200 122300 122400 122500 122600 122700

Frequency (Hz)

Dis

pla

ce

me

nt/

Cu

rre

nt

(um

/A)

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Ad

mit

tan

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Ph

as

e (

De

g)


0.000

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0.010

0.015

0.020

0.025

0.030

0.035

0.040

0.045

0.050

0.055

0.060

0.065

0.070

121700 121800 121900 122000 122100 122200 122300 122400 122500 122600 122700

Frequency (Hz)

Dis

pla

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me

nt/

Vo

lta

ge

(u

m/V

)

-105

-90

-75

-60

-45

-30

-15

0

15

30

45

60

75

90

105

Ad

mit

tan

ce

Ph

as

e (

De

g)

Tool Clamp in -X Direction

Laser Dot

- Hysteresis Gets Worse for Increasing Current (Normal Due to Heating)

- Fairly Constant Current Gain with Sweep Direction and Drive Level

- Some Degradation in Tool Clamping for Higher Current (Typical)

SlopeChange

Hysteresis


0.000

0.005

0.010

0.015

0.020

0.025

0.030

0.035

0.040

0.045

0.050

0.055

121700 121800 121900 122000 122100 122200 122300 122400 122500 122600 122700

Frequency (Hz)

Ad

mit

tan

ce

Ma

g (

S)

-100

-80

-60

-40

-20

0

20

40

60

80

100

Ad

mit

tan

ce

Ph

as

e (

De

g)


Fig. 10. Constant current/velocity Bode for “good” transducer with X-Top velocity.

Fig. 11. Constant current/velocity Bode for “good” transducer with Y-Top velocity.

Fig. 12. Gain ratios with X and Y velocities for “good” transducer.

Constant Velocity Feedback SF5505-14 IConn

0.0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1.0

1.1

1.2

121700 121800 121900 122000 122100 122200 122300 122400 122500 122600 122700

Frequency (Hz)

Dis

plac

emen

t/Cur

rent

(um

/A)

-90

-75

-60

-45

-30

-15

0

15

30

45

60

75

90

Adm

ittan

ce P

hase

(Deg

)


0.0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1.0

1.1

1.2

1.3

121700 121800 121900 122000 122100 122200 122300 122400 122500 122600 122700

Frequency (Hz)

Dis

plac

emen

t/Cur

rent

(um

/A)

-90

-75

-60

-45

-30

-15

0

15

30

45

60

75

90

105

Adm

ittan

ce P

hase

(Deg

)

Feedback VibrometerVoltage Range Up Down

Red 7V 5 mm/s/V Solid DashedGreen 5V 25 mm/s/V Solid DashedBlue 8V 25 mm/s/V Solid Dashed

LegendSweep


0.000

0.005

0.010

0.015

0.020

0.025

0.030

0.035

0.040

0.045

121700 121800 121900 122000 122100 122200 122300 122400 122500 122600 122700

Frequency (Hz)

Dis

pla

cem

ent/V

olta

ge

(um

/V)

-80

-60

-40

-20

0

20

40

60

80

100

Ad

mitt

ance

Ph

ase

(Deg

)

- Fairly Constant Gain With Current/Velocity- X-Clamp/X-Top Current Gain Nearly 1:1


0.000

0.005

0.010

0.015

0.020

0.025

0.030

0.035

0.040

0.045

0.050

121700 121800 121900 122000 122100 122200 122300 122400 122500 122600 122700

Frequency (Hz)

Dis

pla

cem

ent/V

olta

ge

(um

/V)

-100

-80

-60

-40

-20

0

20

40

60

80

100

Ad

mitt

ance

Ph

ase

(Deg

)

Tool Top in -X Direction

Laser Dot

~Same Gain as Clamp


0.0

0.5

1.0

1.5

2.0

2.5

3.0

3.5

4.0

4.5

5.0

5.5

6.0

6.5

121700 121800 121900 122000 122100 122200 122300 122400 122500 122600 122700

Frequency (Hz)

Dis

plac

emen

t/Cur

rent

(um

/A)

-90

-75

-60

-45

-30

-15

0

15

30

45

60

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90

105

Adm

ittan

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hase

(Deg

)


0.000

0.025

0.050

0.075

0.100

0.125

0.150

0.175

0.200

0.225

0.250

121700 121800 121900 122000 122100 122200 122300 122400 122500 122600 122700

Frequency (Hz)

Dis

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(um

/V)

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Ad

mitt

ance

Ph

ase


0.00

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1.50

2.00

2.50

3.00

3.50

4.00

4.50

5.00

5.50

6.00

6.50

121700 121800 121900 122000 122100 122200 122300 122400 122500 122600 122700

Frequency (Hz)

Dis

pla

cem

ent/C

urr

ent (

um

/A)

-90

-75

-60

-45

-30

-15

0

15

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Ad

mitt

ance

Ph

ase

(Deg

)


0.000

0.025

0.050

0.075

0.100

0.125

0.150

0.175

0.200

0.225

0.250

0.275

121700 121800 121900 122000 122100 122200 122300 122400 122500 122600 122700

Frequency (Hz)

Dis

pla

cem

ent/V

olta

ge

(um

/V)

-85

-70

-55

-40

-25

-10

5

20

35

50

65

80

Ad

mitt

ance

Ph

ase

(Deg

)

Frequency (Hz)

C t t V l it F db k SF5



LegendSweep

- Very Consistent Gain With Current/Velocity- Overall Great Performance

Tool Top in -Y Direction

Laser Dot

Constant Current Feedback SF5505-14-16 IConn

10%

11%

12%

13%

14%

15%

16%

17%

18%

19%

20%

21%

22%

121700 121800 121900 122000 122100 122200 122300 122400 122500 122600 122700

Frequency (Hz)

Curre

nt G

ain

Ratio

X-T

op/Y

-Top

-90

-75

-60

-45

-30

-15

0

15

30

45

60

75

90

Adm

ittan

ce P

hase

(Deg

)


0%2%4%6%8%

10%12%14%16%18%20%22%24%26%28%30%32%

121700 121800 121900 122000 122100 122200 122300 122400 122500 122600 122700

Frequency (Hz)

Volta

ge G

ain

Rat

io X

-Top

/Y-T

op

-80-70-60-50-40-30-20-1001020304050607080

Adm

ittan

ce P

hase

(Deg

)


100%

105%

110%

115%

120%

125%

130%

135%

140%

145%

150%

155%

160%

121700 121800 121900 122000 122100 122200 122300 122400 122500 122600 122700

Frequency (Hz)

Curre

nt G

ain

Ratio

X-C

lam

p/X-

Top

-90

-75

-60

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Adm

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hase

(Deg

)


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25%

50%

75%

100%

125%

150%

175%

200%

225%

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275%

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121700 121800 121900 122000 122100 122200 122300 122400 122500 122600 122700

Frequency (Hz)

Volta

ge G

ain

Rat

io X

-Cla

mp/

X-To

p

-90

-75

-60

-45

-30

-15

0

15

30

45

60

75

90

Adm

ittan

ce P

hase

(Deg

)


15%

16%17%

18%19%

20%

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23%

24%25%

26%27%

28%

29%30%

31%

121700 121800 121900 122000 122100 122200 122300 122400 122500 122600 122700

Frequency (Hz)

Cur

rent

Gai

n R

atio

X-C

lam

p/Y-

Top

-80

-70-60

-50-40

-30

-20-10

0

1020

3040

50

6070

80

Adm

ittan

ce P

hase

(Deg

)


0%

3%

6%

9%

12%

15%

18%

21%

24%

27%

30%

33%

36%

39%

121700 121800 121900 122000 122100 122200 122300 122400 122500 122600 122700

Frequency (Hz)

Volta

ge G

ain

Rat

io X

-Cla

mp/

Y-To

p

-90-80-70-60-50-40-30-20-100102030405060708090100

Adm

ittan

ce P

hase

(Deg

)

FEA Predicted

20%

FEA Predicted

25%

FEA Predicted

130%

X-TopY-Top

Gain Ratio

X-ClampY-Top

Gain Ratio

X-ClampX-Top

Gain Ratio


Fig. 13. Standard Bode for “bad” transducer with X-Clamp velocity.

Fig. 14. Constant current Bode for “bad” transducer with X-Clamp velocity.

Fig. 15. Constant velocity Bode for “bad” transducer with X-Clamp velocity.

Velocity/Current 083006-1 Maxum

-40

-30

-20

-10

0

10

20

30

40

50

60

100 102 104 106 108 110 112 114 116 118 120 122 124 126 128 130 132 134 136 138 140

Frequency (kHz)

Un

it V

elo

city

/Am

ps

(dB

)

-400

-200

0

200

400

600

800

1000

1200

Ph

ase

(Deg

)

Mag Mag Down

Phase Phase Down

Velocity/Voltage 083006-1 Maxum

-80

-70

-60

-50

-40

-30

-20

-10

0

10

20

100 102 104 106 108 110 112 114 116 118 120 122 124 126 128 130 132 134 136 138 140Frequency (kHz)

Un

it V

elo

city

/Vo

lts (d

B)

-400

-200

0

200

400

600

800

1000

1200

Ph

ase

(Deg

)

Mag Mag Down

Phase Phase Down

Current/Voltage 083006-1 Maxum

0

5

10

15

20

25

30

35

40

45

50

55

60

100 102 104 106 108 110 112 114 116 118 120 122 124 126 128 130 132 134 136 138 140

Frequency (kHz)

Ad

mitt

ance

Mag

(mS

)

-120

-100

-80

-60

-40

-20

0

20

40

60

80

100

120

Ad

mitt

ance

Ph

ase

(Deg

)

Mag

Mag Down

Phase

Phase Down


Laser Dot

Normal Bode Response

Suspect-25dB Down

Current/Voltage Admittance Loop

-40

-30

-20

-10

0

10

20

30

40

-10 0 10 20 30 40 50 60

G (mS)

B (

mS

)

Constant Current Feedback 083006-4 Maxum Ultra

0.00

0.25

0.50

0.75

1.00

1.25

1.50

1.75

2.00

2.25

123600 123700 123800 123900 124000 124100 124200 124300 124400 124500 124600

Frequency (Hz)

Dis

pla

ce

me

nt/

Cu

rre

nt

(um

/A)

-80

-60

-40

-20

0

20

40

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Ad

mit

tan

ce

Ph

as

e (

De

g)


0.00

0.01

0.02

0.03

0.04

0.05

0.06

0.07

0.08

0.09

0.10

123600 123700 123800 123900 124000 124100 124200 124300 124400 124500 124600

Frequency (Hz)

Dis

pla

ce

me

nt/

Vo

lta

ge

(u

m/V

)

-100

-80

-60

-40

-20

0

20

40

60

80

100

Ad

mit

tan

ce

Ph

as

e (

De

g)


0.000

0.005

0.010

0.015

0.020

0.025

0.030

0.035

0.040

0.045

0.050

0.055

0.060

123600 123700 123800 123900 124000 124100 124200 124300 124400 124500 124600

Frequency (Hz)

Ad

mit

tan

ce

Ma

g (

mS

)

-90

-75

-60

-45

-30

-15

0

15

30

45

60

75

90

Ad

mit

tan

ce

Ph

as

e (

De

g)

- Hysteresis Gets Worse for Increasing Current (Normal Due to Heating)

- Fairly Constant Current Gain with Sweep Direction and Drive Level

- Some Degradation in Tool Clamping for Higher Current (Normal)


Laser Dot

Constant Velocity Feedback 083006-4 Maxum Ultra

0.0

0.2

0.4

0.6

0.8

1.0

1.2

1.4

1.6

1.8

2.0

2.2

123600 123700 123800 123900 124000 124100 124200 124300 124400 124500 124600

Frequency (Hz)

Dis

pla

cem

ent/C

urr

ent (

um

/A)

-75

-60

-45

-30

-15

0

15

30

45

60

75

90

Ad

mitt

ance

Ph

ase

(Deg

)



LegendSweep

- Fairly Consistent Gain with Sweep Direction and Velocity Level

- Little Hysteresis with Sweep Direction

- No Serious Issues at Interface from Parasitic Modes


Laser Dot


0.00

0.01

0.02

0.03

0.04

0.05

0.06

0.07

0.08

0.09

0.10

123600 123700 123800 123900 124000 124100 124200 124300 124400 124500 124600

Frequency (Hz)

Dis

pla

ce

me

nt/

Vo

lta

ge

(u

m/V

)

-100

-80

-60

-40

-20

0

20

40

60

80

100

Ad

mit

tan

ce

Ph

as

e (

De

g)


0.000

0.005

0.010

0.015

0.020

0.025

0.030

0.035

0.040

0.045

0.050

0.055

0.060

123600 123700 123800 123900 124000 124100 124200 124300 124400 124500 124600

Frequency (Hz)

Ad

mit

tan

ce

Ma

g (

S)

-90

-75

-60

-45

-30

-15

0

15

30

45

60

75

90

Ad

mit

tan

ce

Ph

as

e (

De

g)


Fig. 16. Constant current/velocity Bode for “bad” transducer with X-Top velocity.

Fig. 17. Constant current/velocity Bodes for “bad” transducer with Y-Top velocity.

8. Conclusions

The transducer with “good” process performance conforms to behavior as predicted by the ideal linear FEA model with glued interfaces (i.e., no gap elements). Non-linear behavior in the tool was shown to be the root cause of poor process (i.e., low shear force): manufacturing error exacerbated inherent design problem in the tool clamp. Phase changes from closely spaced parasitic modes can lead to hysteresis effects due to interface gapping as seen from the non-sinusoidal velocity profile; heating effects can also cause hysteresis. Velocity based Bode plots can pick-up subtleties typically overlooked without a full laser vibrometer modal survey. A unique set of interrogation locations and assessment criteria is required for each specific transducer design and process application; wire bonding is inordinately sensitive to tool motions due to delicate balance of forces exerted on tiny ball and micro bond pad structure; inconsistent energy delivery to the tool is a root cause of poor process.

- Displacement Stability Issues with Current & Velocity Feedback- Velocity Feedback Unstable Above 2V Due to Oscillation (Non-Sinusoidal Velocity Waveform)- X-Clamp/X-Top Current Gain >10 (Gapping)


0.000

0.025

0.050

0.075

0.100

0.125

0.150

0.175

0.200

0.225

123600 123700 123800 123900 124000 124100 124200 124300 124400 124500 124600

Frequency (Hz)

Dis

pla

cem

ent/C

urr

ent (

um

/A)

-80

-60

-40

-20

0

20

40

60

80

100

Ad

mitt

ance

Ph

ase

(Deg

)


0.000

0.001

0.002

0.003

0.004

0.005

0.006

0.007

0.008

0.009

123600 123700 123800 123900 124000 124100 124200 124300 124400 124500 124600

Frequency (Hz)

Dis

plac

emen

t/Vol

tage

(um

/V)

-80

-60

-40

-20

0

20

40

60

80

100

Adm

ittan

ce P

hase

(Deg

)


0.00

0.01

0.02

0.03

0.04

0.05

0.06

0.07

0.08

0.09

0.10

123700 123800 123900 124000 124100 124200 124300 124400 124500

Frequency (Hz)

Dis

pla

cem

ent/C

urr

ent (

um

/A)

-100

-80

-60

-40

-20

0

20

40

60

80

100

Ad

mitt

ance

Ph

ase

(Deg

)


0.000

0.001

0.001

0.002

0.002

0.003

0.003

0.004

0.004

0.005

123700 123800 123900 124000 124100 124200 124300 124400 124500

Frequency (Hz)

Dis

plac

emen

t/Vol

tage

(um

/V)

-80

-60

-40

-20

0

20

40

60

80

100

Adm

ittan

ce P

hase

(Deg

)

q


Red .5V 5 mm/s/V Solid DashedGreen 1V 5 mm/s/V Solid DashedBlue 2V 5 mm/s/V Solid Dashed

LegendSweep

Phase Changes

Seen

Tool Top in –X Direction

Laser Dot


0.00.5

1.01.52.02.5

3.03.54.04.5

5.05.56.06.5

7.07.5

123600 123700 123800 123900 124000 124100 124200 124300 124400 124500 124600

Frequency (Hz)

Dis

pla

cem

ent/C

urr

ent (

um

/A)

-105-90

-75-60-45-30

-1501530

45607590

105120

Ad

mitt

ance

Ph

ase

(Deg

)


0.00

0.03

0.05

0.08

0.10

0.13

0.15

0.18

0.20

0.23

0.25

0.28

0.30

0.33

123600 123700 123800 123900 124000 124100 124200 124300 124400 124500 124600

Frequency (Hz)

Dis

pla

cem

ent/V

olta

ge

(um

/V)

-90

-75

-60

-45

-30

-15

0

15

30

45

60

75

90

105

Ad

mitt

ance

Ph

ase

(Deg

)


0.0

0.5

1.0

1.5

2.0

2.5

3.0

3.5

4.0

4.5

5.0

5.5

6.0

6.5

7.0

123600 123700 123800 123900 124000 124100 124200 124300 124400 124500 124600

Frequency (Hz)

Dis

pla

ce

me

nt/

Cu

rre

nt

(um

/A)

-105

-90

-75

-60

-45

-30

-15

0

15

30

45

60

75

90

105

Ad

mit

tan

ce

Ph

as

e (

De

g)



LegendSweep

Frequenc


0.000

0.025

0.050

0.075

0.100

0.125

0.150

0.175

0.200

0.225

0.250

0.275

0.300

0.325

123600 123700 123800 123900 124000 124100 124200 124300 124400 124500 124600

Frequency (Hz)

Dis

pla

ce

me

nt/

Vo

lta

ge

(u

m/V

)

-90

-75

-60

-45

-30

-15

0

15

30

45

60

75

90

105

Ad

mit

tan

ce

Ph

as

e (

De

g)

Tool Top -Y Direction

Laser Dot

- Inconsistent Gain With Current/Velocity (∆10%)- Overall Fair Performance- Root Cause: Found MFG Error in Tool Hole- Difficult to Detect with Incoming Inspection

10% Increase


References

C. H. Sherman and J. L. Butler, Transducers and Arrays for Underwater Sound. New York, NY: Springer Science, 2007. D. A. DeAngelis and D. C. Schalcosky, “The Effect of PZT8 Piezoelectric Crystal Aging on Mechanical and Electrical Resonances in Ultrasonic

Transducers,” 2006 IEEE Ultrasonics Symposium, Session P2O-10. D. A. DeAngelis, G. W. Schulze, “Optimizing Piezoelectric Ceramic Thickness in Ultrasonic Transducers,” 2010 UIA Symposium Proceedings,

IEEE XPlore. D. A. DeAngelis, G. W. Schulze, “Optimizing Piezoelectric Crystal Preload in Ultrasonic Transducers,” 2009 UIA Symposium Proceedings,

IEEE XPlore. D. Stansfield, Underwater Electroacoustic Transducers. Los Altos, CA: Peninsula Publishing, 1991. K. Uchino and J. R. Giniewicz, Micromechatronics. New York, NY: Marcel Dekker, 2003. M. Umeda, K. Nakamura, S. Takahashi, S. Ueha, “An Analysis of Jumping and Dropping Phenomena of Piezoelectric Transducers using the

Electrical Equivalent Circuit Constants at High Vibration Amplitude Levels,” Japanese Journal of Applied Physics Vol. 39 (2000) pp. 5623-5628.

O. B. Wilson, Introduction to Theory and Design of Sonar Transducers. Los Altos, CA: Peninsula Publishing, 1991. S. O. Ural, S. Tuncdemir, Y. Zhuang, K. Uchino, “Development of a High Power Piezoelectric Characterization System and Its Application for

Resonance/Antiresonance Mode Characterization,” Japanese Journal of Applied Physics 48 (2009) 056509.

Advanced Bode Plot Techniques for Ultrasonic Transducers

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