Nancatings: The Slutin t All f Our Envirnmental Prtectin Prblems? 2015 NREL Phtvltaic Mdule Reliability Wrkshp February 25, 2015 Presented by Greg Caswell DfR Slutins 2004-2007 2010
Intrductin Applying cnfrmal cating r ptting t prvide envirnmental prtectin t electrnics in utdr applicatins is a very well-knwn and heavily used technique. This is especially true in slar and ther green applicatins due t the severe envirnment (desert and trpical climates) and lng-life expectatins (25 years). A new class f nan-thin catings that prvide superhydrphbic capabilities have entered the marketplace with great fanfare. Superhydrphbicity is defined as having a wetting angle greater than 90 degrees and sme materials have measured wetting angles exceeding 150 degrees.
What s Wrng With Current Materials? Current cnfrmal catings all have their prs and cns Drives users t ptting materials t cmpensate
Sme Issues Cating getting under cmpnents causing lifting Catings are NOT hermetic misture will diffuse thrugh Sulfur penetratin f Silicne resulting in crrsin
Super Hydrphbicity Definitin: Wetting angle far greater than the 90 degrees typically defined as hydrphbic Can create barriers far mre resistant t humidity and cndensatin than standard cnfrmal catings Hw t get there? Depsit materials with existing high surface tensin (e.g., Tefln) Replicate the surface f the Ltus Leaf
Nandepsitin f High Surface Tensin Materials Several cmpanies currently fcused n the electrnics market The key technlgy fr each cmpany is the prcess, nt necessarily the materials
Nancating Cmpanies GVD: Funded in 2001. Spinff frm MIT Key technlgy is initiated chemical vapr depsitin (icvd) and PTFE and Silicne Prtn Plasma Innvatins (P2I): Funded in 2004. Spin ff frm UK MOD Labratry and Durham University Key technlgy is pulsed plasma and halgenated plymer catings (specifically, flurcarbn) Semblant: Funded in 2009. Spin ff frm Ipex Capital Key technlgy is plasma depsitin and halgenated hydrcarbn Barrian (Dry Surface) Key technlgy is the integratin f nanparticles int existing cnfrmal cating material t achieve superhydrphbicity ACT Nan Inc. -Key Technlgy is Advanced nanguard (ANG) that they say can be applied by dipping and is permanent because it is abrasin prf.
Prcess Technlgy Hydrphbicity tends t be driven by number and length f the flurcarbn grups and the cncentratin f these grups n the surface The key pints t each technlgy are: Sme are chemical vapr depsitin (CVD) prcesses, with lw vacuum requirements, Rm Temperature Depsitin Prcess Variety f Ptential Cating Materials (with primary fcus n flurcarbns) Sme incrprate nan-particles int a cnventinal cnfrmal cating
Semblant Prcess
Benefits (especially cmpared t Parylene) These are truly nancatings Minimum Parylene thickness tends t be abve ne micrn (necessary t be pinhle free) These catings can be pinhle free at 100 nm r lwer Nancating allws fr Optical Transparency RF Transparency Rewrkability Eliminatin f masking
N Masking LLCR Measurements Current (A) 0.01 V cmp (V) 0.1 Cnnectr Male 34way Pin Header Au ver nickel cntact (TE Cnnectivity 1-215307-7) Cnnectr Female 34way Scket Header Au ver nickel cntact (TE Cnnectivity 1-826632-7) Curtesy f Semblant
Risks Vltage Breakdwn Levels tend t be lwer cmpared t existing catings (acrylic, urethane, silicne) Can be an issue in terms f MIL and IPC specificatins Optically Transparent Cst Inspectin is challenging Likely mre expensive than cmmn wet catings Hwever, majr cell phne manufacturer claims significant ROI based n drp in warranty csts Thrughput Batch prcess. Cating times tend t be 10 t 30 minutes, depending upn desired thickness Hwever, being used in high vlume manufacturing
Atmic Layer Depsitin (ALD)
ALD Cntinued
Risks The prcess can be very slw (100nm thickness can take ver an hur) Nt rewrkable There have been challenges in regards t cmpatibility f ALD with existing electrnic materials and manufacturing prcess Clean surfaces with similar cefficient f thermal expansin (CTE) wrk best De-adhesin and cracking smetimes bserved when applied t metals, plymers, and surfaces with flux residue (requires sme tailring)
Barrian Dry Surface Water drplets remain perched n the peaks in well-frmed beads that can t adhere t the surface. Barrian duplicates this amazing waterprfing actin by creating a micrstructure f silica glass peaks. This precise surface gemetry, cmbined with advanced lw-surfaceenergy chemistry, results in ptimal water beading that accelerates the flw f water ver the surface, rendering the surface and the structure belw it virtually unwettable
Barrian Their prcess uses current cnventinal cnfrmal cating materials like acrylic and integrates their prprietary nan particle frmulatin int the cating
ACT Nan ACT states that their material can take many frms and be applied mre than nce. Their fcus seems t be n repelling water. N Masking f cnductive Parts Can be integrated int Prductin lines
THANKS Greg Caswell DfR Slutins 301-640-5825 gcaswell@dfrslutins.cm