Advanced Low Dielectric Constant Materials Learning and Perspectives

Transcription

1 Advanced Low Dielectric onstant Materials Learning and Perspectives Geraud Dubois IBM Almaden Research enter, San Jose, A Department of Materials Science and Engineering, Stanford University, A

2 2 4/26/2018

3 utline FEL, MEL, BEL & Packaging Low-k materials: why do we need them? Ultra low-k materials (ULK) mechanical properties hip Package Interaction (PI) lessons learned Ultra low-k materials (ULK) challenging our thinking onclusion 3 4/26/2018

4 MEPTE, New Generation Flexible Hybrid Electronics, April FEL, BEL and PAKAGING T. Wiggins M4 T. Wiggins u Wires M3 BEL ILD M2 V1 u Vias M1 MEL FEL 4 Tungsten Studs FET s (gates)

5 Why did we introduce low-k materials? Rdelay Gate delay Interconnect delay, Al & 2 Sum of delays, Al & 2 Delay (ps) Al 3.0 µm-cm 2 k = 4.0 Al 0.8 µm thick Al line 43 µm long Interconnect Transistors Technology node (nm) 20% performance increase alculated gate and interconnect delay vs technology node according to the National technology roadmap for semiconductor (NTRS) in

6 MIRPRESSRS HISTRIAL EVLUTIN 250nm (6 u levels) 180nm (7 u levels) 130nm (9 u levels) 90nm (10 cu levels) 65nm (10 u levels) 45nm (10 u levels) F- 2 F- 2 H H H k= 4.3 k= 3.8 k= 3.6 k= 3.0 k= 2.7 k= 2.4 u ILD u ILD 480 nm 480 nm 80 nm 80 nm 6 W. Volksen, R. Miller, G. Dubois. hem Rev 2010, 110,

7 IBM Technology Roadmap (250 nm) DIELETRI NSTANT F- 2 (180 nm) F- 2 (130 nm) H (90 nm) H (65 nm) H (45 nm) H (32 nm) YEAR F PRDUTIN (TEHNLGY NDE) 7 4/26/2018

8 Major hallenges for the Integration of ULK (k<2.55) chanical Properties Process Damage ARBITRARY UNITS 2 F- 2 D p-h k < 2.4 PRSITY chanical properties: Young s modulus, hardness, fracture resistance, and adhesion W. Volksen and G. Dubois, Advanced Process damage: Interconnects plasma, wet for chemistries ULSI Technology, M. Baklanov, P.S. Ho, E. Zschech, Eds., Wiley, 2012, hapter 1. 8

9 PI and ULK MATERIALS BEL PAKAGING ULK Young s modulus ULK ohesive strength ULK levels 4 Stiffness Substrate Flexibility Preferred Reality P. Brofman, IEP 2009, Kyoto, Japan, April 14-16, p1-6. More thermo-mechanical stress is applied to the BEL whereas the overall fracture resistance of the BEL has been reduced Packaging Process window BEL Packaging Process window BEL Technology node n Technology node n+1 9

10 WHITE BUMP ISSUES Acoustic microscopy image of white bumps ross-section of white bump PSPI Tension due to Stretching of upper levels of BEL Films. T. Wiggins xide Low K E oxide > E PSPI > E lowk Tension due uplift of the solder bump edge Shear due to package applies moment to 4 10 R.A. Susko et al. ES Trans 16 (19) 2009,

11 MDELING F HIP-PAKAGING INTERATIN ILD E (GPa) MSQ-A 2 MSQ-B 5 ERR at crack 6 vs ILD moduli (TE~10ppm/K) MSQ- 10 MSQ-D 15 VD-SG J. Uchibori et al. AIP Proceedings, Stress-Induced Phenomena in tallization, 10 th Int Workshop, 2009, 185. G. Wang et al. Microelectronics Reliability 2005, 45,

12 MDELING F HIP-PAKAGING INTERATIN E=70 GPa E=23 GPa Influence of higher levels material E observed 12

13 MDELING F HIP-PAKAGING INTERATIN Parameters Variables Effect on ERR onclusion Solder materials - Traditional lead eutectic - Lead-free 2-3 times higher for lead free solder Lower E and smaller TE mismatch with underfill Underfill TE: 28, 34 and 41 ppm Factor of 3 increase between 28 and 41ppm Lower the underfill TE Die attach process - eramic vs organic Up to 8x eramic preferred - With or without underfill Up to 3x BAR type process Die size - 8 x 7 mm 2 15% increase for the x 13.4 mm 2 biggest one Not such a determining factor Interfaces in the interconnect structures parallel to the die surface are more prone to the packaging effect 13 G Wang et al. Microelectronics Reliability 2005, 45,

14 Ultra low-k Materials hemistry MTS 2.7 E SAWS = 7 GPa H H DEMS/BHD k = 2.2, 36SJA3 M D D H T T H Porosity (N 2 ) = 17% Q Traditional Building Blocks hemical Shift (ppm) The hybrid network connectivity dictates: A) thin-film mechanical properties B) mechanical response to the introduction of porosity 14 4/26/2018 MTS

15 Ultra low-k Materials hemistry MTS 2.7 E SAWS = 7 GPa H H DEMS/BHD k = 2.2, 36SJA3 M D D H T T H Porosity (N 2 ) = 17% Q Traditional Building Blocks hemical Shift (ppm) The hybrid network connectivity dictates: A) thin-film mechanical properties B) mechanical response to the introduction of porosity 1,2 15 4/26/2018

16 HI chanical Properties H 3 x y E SAWS (GPa) /26/2018 MSSQ- 2 Et-S -S Density (g.cm -3 ) y = 19.52ρ y = ρ y = ρ Dubois et al., US 7,229,943 (2007) Dubois et al., Adv. Mat. 2007, 19, Dubois et al., Journal of Sol-gel Science and Technology, 2008, 48, 187. Strain Energy Release Rate, G (J/m 2 ) Dielectric onstant, k Dense HI 2.0 k ~ pt. bend G c Density, ρ (g/cm 3 ) D (PEVD) MSSQ (SD) E.P. Guyer et al. J. Mater. Res. 2006, 21, 882.

17 ULK chanical Properties Landscape o New Materials have emerged PEVD (Et) 3 (Et) 3 + BHD (Et) 2 k=2.55 Higher mechanical properties E ~ 10 GPa Spin-on Parameter PS V2 PS V2 Porogen No Yes Dielectric constant ~ 2.4 ~ 2.2 E (GPa) by SAWS D. Edelstein et al. IIT 2012 o Engineering solutions have been found - UV treatment has been implemented (1.5x improvement in E) - New designs have helped with chip packaging interaction (PI) 17 4/26/2018 Lowest k integrated until now is ~ 2.4

18 ARBITRARY UNITS MEPTE, New Generation Flexible Hybrid Electronics, April Major hallenges for the Integration of ULK k < 2.55 chanical Properties Process Damage 2 F- 2 D p-h k < 2.4 W. Volksen Process and damage: G. Dubois, plasma, Advanced wet chemistries Interconnects for ULSI Technology, M. Baklanov, P.S. Ho, E. Zschech, Eds., Wiley, 2012, hapter 1. Plasma Induced Damage (PID) (Ions, Radicals, VUV ) H H H H PRSITY H H chanical properties: Young s modulus, hardness, fracture resistance, and adhesion 18 4/26/2018

19 ARBITRARY UNITS MEPTE, New Generation Flexible Hybrid Electronics, April /26/2018 Major hallenges for the Integration of ULK k < 2.4 chanical Properties 2 F- 2 D p-h k < 2.4 PRSITY Process Damage chanical properties: Young s modulus, hardness, fracture resistance, and adhesion W. Volksen Process and damage: G. Dubois, plasma, Advanced wet chemistries Interconnects for ULSI Technology, M. Baklanov, P.S. Ho, E. Zschech, Eds., Wiley, 2012, hapter 1. Plasma Induced Damage (PID) (Ions, Radicals, VUV ) H H H H H H H H H H k increases Moisture absorption Electrical properties degraded

20 ULK Dilemma 20 4/26/2018

21 1.PREFILL 2.VERBURDEN REMVAL SUBSTRATE SUBSTRATE 3. PATTERNING 4. METALLIZATIN 5. MP u u u u 6. BURN-UT SUBSTRATE SUBSTRATE 21 4/26/2018 US 8,314,005, US 8,492,239, US 8,541,301 T. Frot et al. Future Fab Int. 2011, 39, p.67 T. Frot et al. Adv. Mater. 2011, 23, p.2828 T. Frot et al. Adv. Funct. Mater. 2012, 22, 3043

22 onclusion o ulture of Roadmap o Engineering Solution vs Materials Innovation o The syndrome of 1 Material, many properties 22 4/26/2018

23 Acknowledgements Willi Volksen Teddie Magbitang Reinhold Dauskardt Theo Frot Krystelle Lionti 23 4/26/2018