Nanopackaging: Nanotechnologies in Microelectronics Packaging

Transcription

1 Nanopackaging: Nanotechnologies in Microelectronics Packaging James E. Morris Department of Electrical & Computer Engineering, Portland State University, Portland, Oregon, USA

2 Nanoparticle Properties (High surface/volume ratio catalysts, etc) Nanoparticles single grain, no defects (Mallik) Criterion: Fermi Level in Conduction Band Aguilera-Granja Nanotechnology (2007) (atoms) DIFFUSION Ostwald ripening Coalescence 2 Sintering (thermally activated) Ohring (2002) (Novikov & Nowottnick, ESTC 2010) Melting Point Depression: Normalized curves ~independent of material Solder: 0.05( ) = 24.5K; T M C for ~5nm i.e. 5% at 5nm Sambles, Proc. Royal Soc. (1971) [TEM observations]

3 Melting Point Depression in Nanoparticle No-Pb Solders (Hongjin Jiang et al, ECTC 07) [found by DSC] Temperature ( o C) (Johan Liu et al, EPTC 2008) T m (20)=214 o C T m (10)=204 o C T m (5)=188 o C Bulk Eq.(1) cal. B-sample, T m = o C C-sample, T m = o C Sn-3.0Ag- 0.5Cu Particle radius (nm) SnAg 3 ~5% reduction (K) at 5nm Sn-0.4Co-0.7Cu

4 Printed Nanoparticle Interconnect Deposition (Felba & Schaeffer) e.g. on flex Nanoscale Ag on Si, before and after sintering at 280 (Bai et al) Ag nanoparticle paste : Initially, and after dipping in methanol for 180s, 600s, 3600s at room temperature (Wakuda et al) 4

5 Nanoparticle Sintering Surface treatments to avoid agglomeration [Wong et al, ECTC 06] (Sun & Wong, ECTC 04) e.g. Carboxylate Amine Polymer (Moscicki et al, EMPC 2011) 5 9/22/2011

6 ICA Microvia Fill (PWB) LMP 75 C micro/nano Ag sintering Das & Egitto Cu Ag

7 CNT Properties (Wikipedia) 7 Young s Modulus (Tpa) Tensile Strength (Gpa) Elongation at break (%) SWNT ~1 (1-5) E 16 Armchair 0.94 T T 23.1 Zigzag 0.94 T 94.5 T Chiral 0.92 T MWNT E 150 Stainless steel Kevlar ~0.15 (0.25 T ) ~0.2 ~ ~3.5 (29.6 T ) T Theoretical E Experimental CTE ~ 0 Electrical (Metallic CNT): I max CNT > 1000 x I max Ag/Cu µ CNT ~ 70 x µ Si CNT ropes 10-4 Ω.cm ~2 Nanotubes Diamond Metals Solders Polymers CNT classifications: SWNTs: MWNTs: Single wall SWNT Multi-wall MWNT Armchair Zigzag Chiral (Mallik) 9/22/2011 (Metallic) (Metallic or semiconducting) typ. ⅔ metallic, ⅓ semicond Grow at ~ 900 C Metallic Grow at ~ 700 C ( 365 C) Bulk Thermal Conductivity (W/mK)

8 Open-ended CNTs for electrical contact Xiao et al, ECTC 2009, Oh et al, Nanotechnology, 19 (2008) (7pp)

9 CNT Interconnect (Banerjee, Li, Srivastava NANO 2008) Inductance L bundle = L magnetic + L kinetic, L kinetic = R Landauer /v f Quantum capacitance C Q = 1/R Landauer v f (& C eq < C Q, C electrostatic ) where R Landauer = h/2q 2 = minimum ballistic resistance and v f = Fermi velocity 8x10 5 m/s L kinetic 16nH/μm >>L magnetic 9 9/22/2011

10 CNTs in TSVs Xu et al, Appl Phys Lett (2007) nm MWNTs in 35nm vias Graham et al, Diamond & Related materials (2004)

11 TSV reliability issues (Sinha et al, NMDC 2010) a) Cu filled via at normal temperature b) Copper expansion can fracture the oxide layer above c) Delamination as a result of thermal cycling (Metallic) SWNT thermal expansion coefficient (Jiang et al, J. Eng Materials & Technology, 126 (2004) )

12 Pradham, Duan, Liang, Iannacchione, Nanotechnology, 20 (2009) (7p) Aligned SWNTs CNT Thermal Conductivity Random SWNTs Random MWNTs Graphite 12 9/22/2011

13 CNT Heat Sink on Si (Liu & Wang) 13

14 Graphene for Thermal Management (Balandin) Advancing Microelectronics, 38(4) July/August 2011, 6-10 Nature Materials, 10 Aug 2011, FLG heat spreaders

15 Thermal Conductivity Balandin, Nature Materials, 10 Aug 2011,

16 Health and Environmental Issues & Tort Law: Nano-Ag in the environment: aquatic food chain Nanoparticles & CNTs in the body Company responsibility that product meets FDA safety standards To minimize exposure to litigation, must show: Product designed with safety in mind Workers educated to possible exposure risks Company tracks relevant research, regulations, etc NIOSH website Nanoparticle Information Library Risks evaluated (in collaboration with others?) External statements consistent with internal data/memos Affirmative steps to reduce exposures Filters, gloves, washing, etc Monitors health of workers and consumers ISO9000 parallel: Must be able to show procedures in place If not negligence! punitive damages! Cautions already abound Canaries: Monitor workers; asbestos problems in factories, not public 16 9/22/2011

17 Summary Nanoparticles in Microelectronics Packaging Carbon Nanotubes in Microelectronics Packaging Graphene in Microelectronics Packaging Health & Environment (EHS & ELSI) Other: Solder, nanowires, nanosprings, contacts, adhesion, ECAs, nanoelectronics, modeling, etc References: Nanopackaging: Nanotechnologies in Electronics Packaging, J.E. Morris (editor) Springer (2008) J.E. Morris, Nanopackaging, in Nanoelectronics: Fabrication, Interconnects, and Device Structures, Kris Iniewski (editor), McGraw-Hill (2010) 1 7 9/22/2011