Fan-Out Wafer Level Package（FO-WLP）用 UVレーザー剥 …

1 Fan-Out Wafer Level Package FO-WLP . UV . UV laser Releasable Temporary Bonding Materials for Fan-Out Wafer Level Package (FO-WLP). 1 2 3 4. Kenzo Ohkita Hikaru Mizuno Hiroyuki Ishii Hitoshi Kato 5 6 7 8. Takashi Mori Hiroki Ishikawa Yooichiroh Maruyama Koichi Hasegawa Temporary bonding/de-bonding (TBDB) technology in a FO-WLP process is required to adapt to a low tempera- ture process because of the potential for damage in handling the thin molded compound embedding dies. We have developed laser releasable TBDB materials for low temperature bonding processes that enable UV laser release with high throughput and low thermal/mechanical stress. The developed TBDB materials consist of two layers, an adhesive layer and a release layer.

2 The appropriate Wafer bonding temperature can be controlled by the molecular weight of the polymer which is the main component of the adhesive material. Good bonding property has been seen, even at 160 oC. by adopting the lowest molecular weight polymer. On the other hand, the release layer material exhibits excellent stability that allows for fabrication of RDLs directly onto the layer to give a stacked structure in the Chip-last (RDL-first). method. The laser energies preferred for Wafer release processes are 130 mJ/cm2 for a 308 nm excimer laser and 190 mJ/cm2 for a 355 nm YAG. These materials will be promising for advancements of FO-WLP applications. 1 RDL Fan-Out .. I/O interconnection . Ball Grid Array BGA . FO-WLP Figure 1.

3 FO-WLP. Fan-Out Wafer Level Package FO-WLP 1 . TSV 3D Fan-Out 1 . System in Package FO-SiP . FO-WLP . 1 1994 . 2 2009 JSR Micro, Inc. 3 1998 . 4 1997 . 5 2008 . 6 2008 . 7 1998 . Figure 1 Illustration of conventional BGA and FO-WLP. 8 1999 . 18 JSR TECHNICAL REVIEW 2 .. TBDB .. 4 Table 1 .. Figure 2 T. emporary bonding/de-bonding TBDB in representative FO-WLP process.. Figure 2 FO-WLP . RDL . EMC .. 9 12 .. Temporary bonding/de-bonding TBDB .. EMC . TBDB 200 . Table 2 . RDL . Table 1 De-bonding system comparison Figure 2. Chip Last RDL-first . RDL . 1 8 .. FO-WLP .. Table 2 Characteristics comparison of laser wavelength laser wavelength Item 308 nm 355 nm 532 nm 1064 nm Mechanism Photonic cleavage Photonic cleavage Thermal or Photonic Thermal degradation Thermal effect Low damage Low damage Intermediate High thermal damage Equipment cost Intermediate excimer Low solid state Low solid state Low solid state.

4 JSR TECHNICAL REVIEW 19.. Photochemical mechanism .. Pho- Figure 4 .. tothermal mechanism PGMEA . 13 .. 14 .. 308 nm 355 nm 200 . YAG 2 UV . 15 .. 16 .. UV . FO-WLP . RDL . Chip-first RDL UV . Chip-last . Figure 2 .. Figure 4 .. Figure 3 . 3 .. Tg Thermo-Mechani- cal Analyzer; TMA . 20 m . AGS-500NX .. Thermogravimetric Analysis; TGA 1 % . AR-G2 TA. 1 mm .. Figure 3 L. ayout of laser releasable temporary bonding material in FO-WLP. Thermo-compression Figure 4 Polymer designs of temporary bonding materials. 20 JSR TECHNICAL REVIEW Figure 5 Thermo-compression bonding procedure. bonding 200 mm 500 nm . 280 /5 min . 50 m . 110 /5 min . 200 /10 min . EMC . 200 mm EMC . EVG520 . MPa . Fig- Figure 6 Shear viscosity curves of adhesive materials.

5 Ure 5 . 300 mm . 200 . 2600 Pa s 910 Pa s 110 Pa s Adhe- sive-A1 Adhesive-A2 Adhesive-A3 . UV Nd Table 3 Adhesive-A1 . YAG Adhesive-A2 . 3 355 nm 50 kHz . SUSS Adhesive-A3 Tg . ELD300 XeCl 308 nm 2 . 50 Hz mm 4 mm Adhesive-A3 . UV TBDB .. EMC . 4 Thermo-compression bonding Figure 5 . Table 4 Adhesive-A1 . Thermo-compression bonding 220 . 200 . Adhesive-A2 180 . Adhesive-A3 160 . Figure 6 Table 5 .. JSR TECHNICAL REVIEW 21. Table 3 Film properties of adhesive materials Adhesive material Item Adhesive-A1 Adhesive-A2 Adhesive-A3. a Molecular weight of main polymer relative ratio Glass transition temperature 90 C 90 C 89 C. Tensile strength 62 MPa 62 MPa 52 MPa Elongation 170 130 11 . Elastic modulus GPa GPa GPa Thermal decomposition temperature 1 weight loss under N2 > 350 C > 350 C > 350 C.

6 A. By gel permeation chromatography GPC . Table 4 EMC bonding test results Bonding temperature . 140 160 180 200 220 240. Adhesive-A1. Error Pass Mw relative ratio Adhesive-A2 Error Pass Mw relative ratio Adhesive-A3. Error Pass Mw relative ratio Error void or delamination exist Pass no void and no delamination Table 5 Bonded pairs of EMC and glass carrier Wafer with Adhesive-A3. Bonding o o o o temperature 140 C 160 C 180 C 200 C. Observations minor void No void No void No void No delamination No delamination No delamination No delamination Adhesive-A3 . Figure 5 . EMC Adhesive-A3 . 1000 Pa s .. 200 220 1 .. 22 JSR TECHNICAL REVIEW Table 6 Thermal stress test results of bonded pairs of silicon Wafer and glass carrier with Adhesive-A3.

7 After thermal test After bonding o o 200 C / 1 hr 220 C / 1 hr Observations No void No void No void No delamination No delamination No delamination No Wafer shift No Wafer shift Table 6 . 1 . Adhesive-A3 FO-WLP .. UV 10 .. UV . Chip-last RDL-first TMAH . RDL Table 7 .. UV UV . Adhesive-A1 . 300 mm UV . Figure 7 355 nm YAG 308 nm XeCl . 308 nm 355 nm . Table 8 . 308 nm 500 nm . Table 7 Chemical resistance of release layer material Chemicals Condition Result o Acetone 25 C/10 min Pass o PGME 25 C/10 min Pass o PGMEA 25 C/10 min Pass o Isopropyl alchol 25 C/10 min Pass o PR stripper 60 C/30 min Pass o Hydrogen peroxide aq. 30 50 C/10 min Pass o Sulfuric acid aq. 10 25 C/30 min Pass o TMAH aq. 25 C/10 min Pass Figure 7 T. ransmittance of release layer material at 308 nm and 355 nm.

8 Pass: Film thickness change is within 10 % and no appearance change JSR TECHNICAL REVIEW 23. Table 8 laser release results of 300 mm bonded silicon Wafer and glass carrier laser wavelength Irradiated condition laser release Optical micrograph through the glass carrier 2. 308 nm 130 mJ/cm OK. 2. 355 nm 190 mJ/cm OK.. 200 mJ/cm 2. Adhesive-A3 EMC . 160 . 300 mm UV . 1 308 nm . 60 355 nm 90 . 308 nm 355 nm EMC Adhesive-A1 200 mJ/cm2 . 355 nm UV . EMC .. Chip-last RDL-first . EMC RDL .. FO-WLP TBDB . O2 .. Hikaru Mizuno, Hiroyuki Ishii, Hitoshi Kato, Takashi Mori, 5 Hiroki Ishikawa Yooichiroh Maruyama, Kenzo Ohkita, 2 UV Koichi Hasegawa: Proc. 2018 ICEP-IAAC 2018 . , 24 JSR TECHNICAL REVIEW References 8 J. H. Lau: Chip Scale Review Magazine: Ed.

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