laser induced die transfer and patterning

LASER INDUCED DIE TRANSFER AND PATTERNINGdr.ir. GERT-WILLEM RÖMER

Workshop "Microassembly: Robotics and Beyond" with IEEE International Conference on

Robotics and Automation ICRA 2013, May 10th, 2013, Karlsruhe, Germany

LASER INDUCED DIE TRANSFER AND PATTERNINGPRINCIPLE OF LASER MATERIAL PROCESSING

2

Laser beam (emitted

by laser source)

LASER MATERIAL PROCESSING

3

Lens


4

Material


5

Track


6

Additional material

• gas

• wire

• paste

• powder


7

Surface


8

Processed material


9

Absorbed laser energy can be used for, material

removal

modification

addition

LASER MATERIAL PROCESSINGPROCESSES

10

Material removaldrilling, cutting


11

Material modificationwelding, marking, bending, transformation hardening


12

Additive processesSoldering, cladding, 3D printing (Selective Laser Sintering/Melting)

LASER MATERIAL PROCESSINGADVANTAGES

13

Laser material processing is:

fast

accurate

flexible in terms of:

• the type of material to be processed and

• product geometry

small heat-affected-zone (HAZ)

contact-free tool

easy to automate


Two types of laser processes:

1. Pyrolytic processes:

thermal processing

typical processing dimensions 1 mm

2. Photolytic processes:

chemical processing (breaking chemical bonds)

typical processing dimensions 0.1 m

14

Two examples/applications:

(both in the field of micro-assembly)

1. Laser induced Die transfer (pyrolytic)

2. Laser patterning for fluidic self-alignment (photolytic)

CONTENTS

15

LASER INDUCED DIE TRANSFER

CONTENTS

16

PYROLYTIC PROCESS

LASER INDUCED DIE TRANSFERPRINCIPLE

17

TapeGlue

Micro part (Si)

Receiver

Laser Die Transfer is a technique to:

release a micro-component (e.g. Si 300300200m3)

from its carrier (tape), and

propel it towards a receiving substrate


18

Laser

beam

Lens


19

Absorption of

laser energy


20

Part propulsion


21

Part positioned on receiver

LASER INDUCED DIE TRANSFERTWO POSSIBLE APPROACHES

22

Two possible approaches:

Absorbed laser energy is used for:

1. Heating of the interface of

(thermal sensitive) tape and

micro part

2. Explosive evaporation of the

interface of tape and micro part

LASER INDUCED DIE TRANSFERQUESTIONS

23

Questions studied in this project were:

Which process (heating or evaporation) works best?

What are achievable accuracy and speed of die transfer?

Will the micro part (Si die) be thermally damaged?

LASER INDUCED DIE TRANSFEREVAPORATION INDUCED RELEASE EXPERIMENTS

24

Laser source: Rofin Sinar RS.M-50D

Pulse duration: 45 ns

= 1064 nm (IR)

Top hat intensity profile

Focus diameter: 100 to 200 m

Parts:Si die 335335190 m3

Tape: Nitto STW “blue” tape

• 100 m PVC foil, with

• 50 m adhesive


25

After release the die:

Rotates/tumbles

Velocity 4 to 6 m/s

Deviates ±4 deg. from vertical

Time between frames: 100 s


26

Placement accuracy (of die on receiver):

x = hsin

were h = tape-to-receiver gap

With = ± 4º and h = 0.5mm x = 34.8 m < 35 m

LASER INDUCED DIE TRANSFERTHERMAL INDUCED RELEASE EXPERIMENTS

27

Laser source: Unitek Miyachi ML-50A

Pulse duration: 0.2 ms

= 532 nm (Green)

Top hat intensity profile

Focus diameter: 540 m

Parts:335335190 m3

Tape: Revalpha tape


28


29

Less rotation/tumbling

Velocity 0.8 to 1 m/s

Deviates ±2 deg. from vertical

(= well within specs)

Time between frames:

• (a) & (b) 500 s

• (c) & (d) 400 s


30

Finite Element Model (FEM)

Temperature distribution

at moment of die

release (after 0.073 ms)

Tmax< 400 K < Tdamage

Tdamage= 673 K

Ep= 5.94 mJ

PHD THESIS

31

http://dx.doi.org/10.3990/1.9789036532600

LASER PATTERNINGFOR FLUIDIC SELF-ALIGNMENT

CONTENTS

32

PHOTOLYTIC PROCESS


33

Photolytic processing = chemical processing,

i.e. photon-induced breaking of chemical bonds

Requires high photon intensity and/or

(ultra) short laser pulse

Laser pulse duration >1 ns thermal processing

Laser pulse duration < 1 ps cold processing

LASER MATERIAL PROCESSINGLONG PULSE PROCESSING

34

LASER MATERIAL PROCESSING(ULTRA) SHORT PULSE PROCESSING

35


36

B.N. Chichkov, C. Momma, S. Nolte, F. von Alvensleben, and A. T¨unnermann. Femtosecond,

picosecond and nanosecond laser ablation of solids. Appl. Phys. A, 63:109–115, 1996


37

Advantage: accurate processing

Disadvantage: low removal rate

10 m3 to 100 m3 per pulse

FLUIDIC DRIVEN SELF-ALIGNMENTFOR EFFICIENT AND PRECISE 3D POSITIONING OF MICROPARTS

38

Aligned

parts

Receptor

site

Liquid

droplet

Gripper

with part

Part on

dropletCapillary

forces aligns

part

(typ. 100100m2)

(after droplet

evaporates)


39

• Relies on accurate hydrophobic-hydrophilic pattern

(or wetting contrast) to pin droplet to receptor site

• Approach: use laser to create hydrophobic-

hydrophilic patterns (receptor sites).


40

Factors determining wetting properties of a surface:

1. Chemical composition

2. Topography:

a. roughness or texture (area)

b. obstacles or edges (lines)


41

Edge approach


42

Edge approach


43

Edge approach


44

Substrate (lead frame)


45

Experimental setup Laser source: Trumpf TruMicro

• Pulse duration: 6.7 ps

• = 1030 nm (IR)

• THG: = 343 nm (UV)

• Linear polarized

• Gaussian fluence profile

• M2<1.3

• Galvo-scanner

• Telecentric f -lens (100mm)

• Focus diameter: 15.6 m

• Clean room: class 4

• 20 ºC, Rel. Humm. 50%,


46


47

Confocal Laser Scanning Microscope image

1 µJ, N=4


48


49

Receptor sites


50

Fluidic test setup

Part: SU-8 chip

Liquid: water


51

Fluidic test setup


52

Site: 200×200 µm2


53

Site: 200×200 µm2


54

Results

• Each receptor site was tested 11 times

• 100% successful alignment is <140º

• Accuracy:

• Position: 0.25±0.86 µm

• Angular: 0.35±1.22º

THANK YOU FOR YOUR ATTENTION

CONTENTS

55

CONTACT

56


57

• Typical position accuracies: <1 m & <0.5 (for m2

parts)

• Typical initial positioning tolerance: 50% of part length

• When combined with pick-and-place robot fast and

accurate assembly process


58


59


60

Chemical approach


61

Roughness approach


62

Edge approach

Gibbs’ inequality:

Y < < (180 – α) + Y

Y : Young’s contact angle Y


63

Experimental setup


64

• Commercial leadframe with

roughened PrePlated Finish

(PPF)

• Surface roughness:

Ra1.5m

• Polyimide foil (polymer)

• Surface roughness:

Ra0.04m

Substrates


65

Experimental approach

• Machining of single trenches by applying pulses:

Overlapping pulses:

@ 400 mm/s & 400 kHz

implies: 94% pulse overlap

Parameters varied:

• Pulse energy: 0.25, 0.5 & 1 µJ

• Number of overscans : N=1 … 25

laser induced die transfer and patterning

Documents