Opportunities and Challenges for Fan-out Panel Level Packaging (FOPLP)

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September 2015 Tanja Braun

Opportunities and Challenges

for Fan-out Panel Lev el Packaging

(FOPLP)

T. Braun (1_{), M. Töpper (}1_{), S. Raatz (}1_{), S. Voges (}2_{), R. Kahle (}2_{), V. Bader (}1_{), J. Bauer (}1_),

K.-F. Becker (1_{), T. Thomas (}2_{), R. Aschenbrenner (}1_{), K.-D. Lang (}2₎

(1_{) Fraunhofer Institute for Reliability and Microintegration}

Gustav-Meyer-Allee 25, 13355 Berlin, Germany e-mail: [email protected]

phone: +49-30/464 03 244 fax.: +49-30/464 03 254 (2_{) Technical University Berlin, Microperipheric Center}

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Outline



Motiv ation for Panel Lev el Packaging



PLP Res ults



As s em bly on 24”x 18” Panel Lev el



Com pres s ion Molding



Die S hift



Redis tribution Outlook



S um m ary : Adv antages & Challenges for FOPLP

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FOWLP/FOPLP Process Flow Options

Die assembly on carrier

Wafer/panel overmolding

Carrier release

RDL (e.g. thin film, PCB based, …), balling, singulation

Apply thermal release tape on carrier Apply release layer on carrier

RDL (e.g. thin film, PCB based, …)

Carrier release, balling, singulation

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Roadmap Fan-Out Panel Level Packaging

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Challenges for Panel Packaging

as s em bly com pres s ion m olding carrier preparation debonding redis tri-bution handling, thinning & s ingulation E q u ip m e n t M a te ri a l _{• Carrier}  steel, glass,..? • Thermo release tape  Alternatives? • EMC  liquid, granular, sheet? • Dielectric polymers  liquid or film?  photosensitive or not? • Sputter targets • Plating • Handling carrier  Tape or other material  Temporary adhesives • Tape laminator  Available automatic equipment?

• Pick and Place  Accuracy on panel size? • Material application  Dispensing, sprinkle, … • Molding  Uniformity, thickness control, … • Debonder  Available automatic equipment? • Lithography  Stepper, laser ablation, LDI • Sputtering, plating  Thickness variation, lines & spaces

• Thinning & Dicing  Available

automatic equipment?

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From Wafer to Panel Size for Fan-out Packaging

24“ x 18“

610 x 457 mm²

12“

300 mm

8“

6“

Wafer Technologies

PCB Technologies

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IZM Wafer Level Packaging Line (RDL)

for Wafer Sizes 100 mm / 150 mm / 200mm / 300 mm

Sputter Spin Coater Mask Aligner Wafer Plating Wet Etching

Spin Coater

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IZM Panel Level Embedding Line

from Wafer Scale to Panel Scale 610 x 456 mm²/24”x18”

Datacon evo/ ASM Siplace CA3

Mahr OMS 600/ IMPEX proX3 WL: Towa up to 8” PL: APIC up to 18”x24” incl. 12” WL Lauffer/ Bürkle Siemens Microbeam/ Schmoll Picodrill with

HYPER RAPID 50 Ramgraber automatic plating line Schmoll MX1 Orbotech Paragon Ultra 200 Schmid CREAMET 600 CI 2 S3

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FOWLP/FOPLP Process Flow Steps

Carrier release

RDL (e.g. thin film, PCB based, …), balling, singulation

Apply thermal release tape on carrier Apply release layer on carrier

RDL (e.g. thin film, PCB based, …)

Carrier release, balling, singulation

Mold first

RDL first

24”x 18” 24”x 18”

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High Speed Assembly on 24”x18”

 Assembly of dies and fiducials

 5.680 chips (2 x 3 x 0.25 mm³) have been placed on the panel

 Assembly speed of

~ 6.500 chips/h using one collect and place 20-nozzle revolver head

 using four assembly heads maximum assembly speed could be accelerated up to 32.000 chips/h

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Assembly Strategies on 18”x 24”

G1 G2 G3 B A B A B A B A C C C C B

initial fiducial dies

A -300 -200 -100 0 100 200 300 -0,10 -0,08 -0,06 -0,04 -0,02 0,00 0,02 0,04 0,06 0,08 0,10  x [m m] x-position [mm] -200 -100 0 100 200 -0,10 -0,08 -0,06 -0,04 -0,02 0,00 0,02 0,04 0,06 0,08 0,10  y [m m] y-position [mm] -300 -200 -100 0 100 200 300 -0,10 -0,08 -0,06 -0,04 -0,02 0,00 0,02 0,04 0,06 0,08 0,10  x [m m] x-position [mm] -200 -100 0 100 200 -0,10 -0,08 -0,06 -0,04 -0,02 0,00 0,02 0,04 0,06 0,08 0,10  y [m m] y-position [mm] Assembly Option A:

three fiducial dies have been placed first and in a second step all other dies have been place in reference to the initial fiducial dies

Assembly Option B:

Global fiducials (G1, G2 and G3) have been assembled first. Local fiducial dies for the four segments (A, B, C) have been placed in a second step in reference to the global fiducials. Finally all other dies are

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Compression Molding - Principle

2 – 15 min

 Short cycle time

 Constant temperature

-> no heating or cooling ramps

 No full compression pressure over longer time

 PMC and mold release extra process steps Vacuum Mold Tool Mold Tool Wafer Cavity Release Film EMC process profile process principle

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Molding Compounds for Large Area Encapsulation

Liquid Compression

Molding Compounds

Granular Compression

Molding Compounds

Sheet Lamination

Molding Compounds

 Standard material for wafer level embedding

 Paste-like material is

dispensed in the cavity and flows during tool closing and compression of the tooling

 Limited potential for large

area due to complex

dispense patterns needed and longer flow length?

 €€

 Standard material for MAP compression molding

 Granular material is

distributed nearly homo-geneously all over the cavity and melts and the droplets have to fuse during closing and compression of the tooling

 No limitations for large area application

 €

 Standard material for wafer level embedding

 Material sheets are

melting and only flow around dies for

encapsulation

 Sheets in defined thicknesses/volume

 No limitations for large area application

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Material Evaluation for Compression Molding

properties A B

liquid granular

filler content 89 wt.-% 90 wt.-%

filler cut size 75 µm 55 µm

CTE₁ 7,5 ppm/K 7,2 ppm/K

CTE₁ 33 ppm/K 30 ppm/K

T_g 165 C 175 C

flexural modulus @ RT 22 GPa 27 GPa

mold temperature 125 C 125 C

inmold cure time 600 s 420 s

PMC temperature 125 C 125 h PMC time 1 h 2 h 40 60 80 100 120 140 160 180 -0.04 -0.02 0.00 material B material A hea t flow [W/ g] temperature [°C] 20 40 60 80 100 120 102 103 104 105 106 107 material B visco sity [Pas] temperature [°C] material A DS C Rheology

 Comparable cured material properties

 Comparable low mold and cure temperature but different cure times

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Mold Compound Application

Liquid EMC

Granular EMCs

 Dispensing of dot patterns

 Volume control by insitu weighing

 Homogeneous spreading

 Volume control by weighing

 Manually by sieve technology, automatically by vibrating unit

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Compression Molding on 12”/300 mm Wafer Size

Liquid EMC

Granular EMCs

 Dispensing of one dot in the center

 Homogeneous filling without flow marks or knit lines

 Homogeneous spreading

 Homogeneous filling without flow marks or knit lines

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Compression Molding on 24”x18” Panel Size

Liquid EMC – Evaluation of dot size pattern

 Evaluation of different dot patterns – target panel thickness of 450 µm (~ 250 g)

 Dispense time with state of the art material and equipment 20 – 30 min

1 ₂

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Compression Molding on 24”x18” Panel Size

Liquid EMC – Evaluation of dot size pattern

 Complete filling of the 24”x18” panel feasible

 Strong flow marks and knit lines for all patterns, dispense time too long



1 ₂

3 ₄

Strong flow marks and knit lines

 Panel broken along knit line

Strong flow marks and knit lines

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Compression Molding on 24”x18” Panel Size

Granular EMC – Evaluation of spreading

 Evaluation of two different spreading patterns – target panel thickness of 450 µm (~ 250 g)

o Dot pattern

o Homogeneous spreading

 Application time with state of the art material and manual equipment 5 – 10 min

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Compression Molding on 24”x18” Panel Size

Granular EMC – Evaluation of spreading

 Complete filling of the 24”x18” panel feasible

 Granular compound distribution has also an influence on flow marks

 Homogeneous distribution of the compound required

1 ₂

Flow marks in the shape of the granular dot pattern

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Compression Molding on 24”x18” Panel Size

Liquid EMC

Granular EMCs

 Molded panels with liquid EMC show less flow marks as blank panels

 Significant marks only visible at the panel edges where no dies are assembled

Molding of panels with assembled dies

(die thickness: 250 µm, mold thickness: 450 m)

 Molded panels with granular EMC show nearly no flow marks

 Encapsulation of assembled panels with liquid and granular compound feasible

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Die Shift on 18”x 24”

initial fiducial dies

A

Assembly Option A:

three fiducial dies have been placed first and in a second step all other dies have been place in reference to the initial fiducial dies

-300 -200 -100 0 100 200 300 -0,6 -0,5 -0,4 -0,3 -0,2 -0,1 0,0 0,1 0,2 0,3 0,4 0,5 0,6  x [m m] x-position [mm] -200 -100 0 100 200 -0,6 -0,5 -0,4 -0,3 -0,2 -0,1 0,0 0,1 0,2 0,3 0,4 0,5 0,6  y [m m] y-position [mm]

 Linear die shift in x- and y-direction => compensation possible

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Die Shift on 18”x 24”

G1 G2 G3 B A B A B A B A C C C C B Assembly Option B:

Global fiducials (G1, G2 and G3) have been assembled first. Local fiducial dies for the four segments (A, B, C) have been placed in a second step in reference to the global fiducials. Finally all other dies are assembled in reference to the local fiducials.

-300 -200 -100 0 100 200 300 -0,6 -0,5 -0,4 -0,3 -0,2 -0,1 0,0 0,1 0,2 0,3 0,4 0,5 0,6  x [m m] x-position [mm] -200 -100 0 100 200 -0,6 -0,5 -0,4 -0,3 -0,2 -0,1 0,0 0,1 0,2 0,3 0,4 0,5 0,6  y [m m] y-position [mm]

Reference to global fiducials

 Comparable results to assembly option A

 Linear die shift in x- and y-direction => compensation possible

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Die Shift on 18”x 24”

G1 G2 G3 B A B A B A B A C C C C B Assembly Option B:

Global fiducials (G1, G2 and G3) have been assembled first. Local fiducial dies for the four segments (A, B, C) have been placed in a second step in reference to the global fiducials. Finally all other dies are assembled in reference to the local fiducials.

Reference to local fiducials

 Linear die shift in x- and y-direction in each quarter => compensation possible

 Same slopes in all quarters

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RDL on Panel Size – Quo Vadis?

24“ x 18“ 610 x 457 mm² 12“ 300 mm 8“ 6“ PCB based technologies

 Already available on panel level – proof of concept has been demonstrated

 Currently limited to 10 µm lines and spaces

 Maskless adaptable processes possible

 No die surface opening possible for e.g. sensors or LEDs

 Low cost potential Thin film technologies

 Proven and established process for FOWLP

 Fine line structuring down to 2 µm lines and spaces

 Die surface opening possible for e.g. sensors or LEDs

 Quite expensive equipment

 No simple upscaling of technologies from WL to PL

 Not one solution for everything

 Application defined – “best of both worlds”

 New materials in combination with new processes must be developed

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• Electrical Performance:

Proof of concept for very RF-Modules beyond 30 GHz.

• Improved wiring and I/O:

There is several decades of experience in fine line wiring and

interconnection technology in the IC industry that can be leveraged for

packaging technology.

• Standardization:

Standardization is key for embedding die package to multi-sourcing

• Thermo-mechanical reliability :

Improved reliability compared to FIWLP due to additional plastic

packaging

• Cost:

Cost advantages are perceived with the ultra-miniaturized approach

proposed when coupled with large area, high throughput and high

volume production.

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Challenges for FOPLP

• Warpage ( Assembly, Manufacturability)

• Heterogeneous materials and non-symmetric structure cause bow

• Polymer materials with adapted CTE& modulus and low shrinkage are

required

• Optimized layer sequence and design required

• Accuracy/Resolution ( Miniaturization)

• Improved optical recognition systems for placement equipment

• Die shift compensation

• Imaging with high depth of focus and high resolution

• Local alignment  LDI or scanner or stepper

• Yield ( Cost)

• Suited materials and components

• Optimized processes

• Production experience  learning curve

• Low k Polymers for RDL ( Performance)

• Standard epoxy polymers are not sufficient for high performance RDL

• Low k with low loss are essential for RF performance

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FOPLP – Current Status

cost

performance

f(L/S, pitch, no. dies, ….)

PL

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Fraunhofer IZM FOPLP Industrial Consortium

Phase I

cost

performance

PL

WL

 Validation of current FOPLP concerning equipment, material, performance and cost