Towards Industrialization of Fan-out Panel Level Packaging

Towards Industrialization of Fan-out Panel Level Packaging Tanja Braun S. Voges, O. Hölck, R. Kahle, S. Raatz, K.-F. Becker, M. Wöhrmann, L. Böttcher, M. Töpper, R. Aschenbrenner 1

Outline Introduction Fan-out Wafer and Panel Level Packaging FOPLP technology background and standardization Status FOPLP o Carrier selection o Assembly o Compression Molding o RDL o Thinning, singulation, handling Summary & Outlook 2

FOWLP/FOPLP Process Flow Options face-dow n Mold first face-up RDL first Apply thermal release tape on carrier Apply temporary bond layer on carrier Apply release layer on carrier Face-down die assembly on carrier Face-up die assembly on carrier RDL (e.g. thin film, PCB based, ) Wafer/panel overmolding Wafer/panel overmolding Die assembly on carrier Carrier release Mold back grinding and RDL Wafer/panel overmolding RDL (e.g. thin film, PCB based, ), balling, singulation Carrier release and singulation Carrier release, balling, singulation 3

Fan-out Package Roadmap Evolution 2014 2015 2016 2015 Source: Yole 4

Thin Film Panel Level 5

Panel Formats Area [mm²] 700.000 GEN4 600.000 500.000 400.000 300.000 200.000 100.000 0 6 8 12 18 21 x21 515x510 mm² 12 x18 18 x24 21 x24 GEN1 GEN2 Wafer PCB LCD GEN3 6

IZM Panel Level Embedding Line from Wafer Scale to Panel Scale 610 x 456 mm²/24 x18 Datacon evo2200/ 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 Schmoll MX1 CREAMET 600 CI 2 S3 Ramgraber plating line Orbotech Paragon Ultra 200 Schmid 7

IZM Wafer Level Packaging Line (RDL) for Wafer Sizes 100 mm / 150 mm / 200 mm / 300 mm Sputter Spin Coater Mask Aligner Wafer Plating Wet Etching Spin Coater Mask Aligner Spin Coater N2 Oven RIE 8

FOWLP Panel Sizes under development (Source: TechSearch International 2015) 9

Equipm ent Material Semicon Taiwan 2017 Panel Packaging Process Step Tasks To Solve Tape laminator Pick and Place Accuracy on panel size? Material application Dispensing, sprinkle, Molding Uniformity, thickness control, Debonder Lithography Stepper, laser ablation, LDI Sputtering, plating Thickness variation, lines & spaces Thinning & Dicing carrier preparation assembly compression molding debonding redis tribution handling, thinning & s ingulation 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 11

Carrier Material for FOWLP & FOPLP Metal / Steel Glass Polymer State of the art for Chip first FOWLP Wide range of CTEs available with special alloys (e.g. Invar, Alloy 42, 48, 49, ) Temperature stable Mechanical stable Reusable Machinable High density -> heavy Limited availability of large sheets State of the art for RDL first FOWLP Wide range of CTEs available (e.g. 3,3 12 ppm/k) Temperature stable Easy to break Sensitive to temperature gradients Limited Reusable Limited Machinable Medium density -> fair weight Limited availability of large sheets Wide range of CTEs available with different filler content and type (e.g. PCB like) Limited mechanical stability Limited temperature stability Not Reusable Machinable Low density -> lightweight 13

Panel Assembly Infrastructure - Carrier Selection Die Shift Factor Comparison on Wafer between Glass (6,75 ppm/k by AGC) and Steel (12 ppm/k) 0,10 0,10 X [mm] 0,08 0,06 0,04 0,02 0,00-0,02-0,04 X [mm] 0,08 0,06 0,04 0,02 0,00-0,02-0,04-0,06-0,08 glass -0,10-100 -80-60 -40-20 0 20 40 60 80 100 X [mm] -0,10-100 -80-60 -40-20 0 20 40 60 80 100 X [mm] Carrier X Direction standard error Y Direction standard error [mm/mm] [mm/mm] steel 8,04 10 04 0,261 10 04 7,20 10 04 0,200 10 04 glass 0,87 10 04 0,213 10 04 0,65 10 04 0,167 10 04 Die Shift Factor: Linear displacement of dies after molding (CTE EMC = ~7 ppm/k) -> mainly due CTE mismatches and chemical shrinkage of EMC. Die shift on the glass carrier is much lower than on the steel carrier. But: Robustness of glass carriers needs improvement -0,06-0,08 steel 14

Challenges for FO Large Area Assembly Placement Speed Larger area: 8 Wafer to 18 x24 Panel -> almost 10 times bigger Increasing amount of components per package -> up to 1 million parts per panel (Cycle time for mass production) Placem ent Accuracy Decreasing pad sizes, pitches and line/spaces Increasing package density Proces s ing Tem perature Increasing influence of the temperature due to the CTE of the carrier material Non homogeneous ambient temperature through the die shift evaluation / compensation process -> provides less accurate compensation results Heterogeneous Integration Dem ands Increasing component variations -> bare die/smds/mems/leds/ Additional components for vertical connections (through mold vias) Investigate Process Alternatives RDL first -> thermode bonding Alternatives for thermal release tapes -> thermode bonding / laser release? 16

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 Cleanroom compatible 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 homogeneously all over the cavity and melts and the droplets have to fuse during closing and compression of the tooling Dusty not cleanroom compatible No limitations for large area application Newly available material Material sheets are melting and only flow around dies for encapsulation Sheets in defined thicknesses/volume No automated handling concept available until now No limitations for large area application 18

Large Area Compression Molding Challenges: Material application e.g. dispense pattern Flow marks and welding lines Die shifting and die sliding Flying dies Warpage Liquid EMC dispensing 10 7 viscosity * [Pas] 10 6 10 5 10 4 10 3 1.00 rad/s 3.16 rad/s 10.00 rad/s 31.62 rad/s 100.00 rad/s 10 2 10 1 30 40 50 60 70 80 90 100 110 temperature [ C] Material characterization and flow simulation v x 19

RDL for Fan-out WLP /PLP 1 st Gen WLP (starting 1994) 2 nd Gen WLP BGA AMD MCM der Wii 3 rd Gen WLP / PLP (Wafer/Panel techn.) Panel technology / organic Interpos er multi layer technology/ silcon Unimicron Intel 21

From Fan-In WLP to Fan-Out PLP Multi-layer RDL WLP technology -Liquid polymer Ex cellent planarization is the key for fine-line routing! PCB technology -dry film IC IC C 22

Polymer coating on Panel Level Liquid Film Dry Film Spin coating Polymer/ Resist coating Vacuum applicator Slit coating Hot roll lam. Toray - Uniformity - Throughput - Topography compensation - Developing concepts for wafer/panel 23

Lithography for Fan-Out Panel Level Non-photo Laser Stepper stepper Photosensitive Laser direct imager Excimer Laser Large-area Ablations Lithography Mask ELD300 Suss Maske aligner & Projection scanner Stepper Orbotech DSC500 Suss Rudolph - Fine line structuring - Compatible to resist & dielectric - Die shift adaptation - Throughput - Photo / non- photosensitive - Maskless processing - Substrate warpage 24

Thinning of Molded Panels 24 x18 panel grinding Automated grinding on tape without support carrier Grinding of molded panels without dies: 450 µm -> 300 µm Grinding of molded panels with dies 450 µm (die thickness 250 µm) -> 200 µm Successful grinding of panels down to 300 and 200 µm final thickness without support carrier Handling of 200 µm thin panel without carrier is critical -> one panel cracked during grinding tape removal TTV ~ 7 11 µm with potential for further process optimization No die cracking 26

Handling of Molded Panels Molded panels are brittle and self-bending compared to PCB or glass panels! Handling concepts are needed for thinner panels e.g. temporary carriers or clamping frames Standardization is also needed for handling, transportation and packaging (e.g. boxes) Only costumer-specific solutions are available 27

PLPC Current Status performance f(l/s, pitch, no. dies,.) WL PL cost 30

PLPC Overview of Phase I and II performance f(l/s, pitch, no. dies,.) WL PL cost Phase I Validation of current FOPLP concerning equipment, material, performance and cost Differentiation against FOWLP Phase II FOPLP enhancement with adapted/optimized equipment and materials Developments in direction of higher performance and lower cost 31

Thanks for your attention! 32