Metallization of MID Dec 2 010

Transcription

1 Metallization of MID Dec 2010

2 Agenda Introduction to Dow Electronic Materials MID Applications & Advantages Dow MID Metallization Processes Plating Equipment Summary

3 Dow Business Structure Where Dow Electronic Materials Fits

4 Dow Electronic Materials Organization and Product Portfolio Semiconductor Technologies Interconnect Technologies Display Technologies Growth Technologies Leading technology that supports the continuing shrinkage and increased power of semiconductor devices. Advanced photoresists, BARCs, metallization, CMP pads and slurries, and related materials. Innovations that enable high-density circuit boards. Technology that increases solar cell efficiency. Advanced metallization and imaging materials. Leading technologies that improve brightness, color saturation, viewing angle, and light management for LCD, plasma, and OLED displays Multi-functional films, LED backlight films, optical filters, OLED materials. Business incubation center to help nurture and grow new and existing smaller EM businesses. Enabling materials used in semiconductor processing, advanced packaging, and optical applications.

5 Interconnect - PWBs A Global leader in developing and delivering innovative metallization and imaging materials for printed circuit, photovoltaic and IC Packaging applications Desmear Electroless Copper Electroplate PHOTOVOLTAIC IMAGING FINAL FINISH 25 um developed resist resolution 18 um etched w ith copper chloride Pre Etch: 40.5um

6 Electronic and Finishing Market Segments A Global leader in developing and delivering innovative materials and surface finishing processes used in electronics and industrial applications IC Package Connectors Passives (Sn,Sn/Pb, Ni, Ag, Au, Pd ) (Ni, PdNi, Au Sn, Sn/Pb,) (Sn, Ni, Post Dips) TAB (Immersion Sn) Steel Mills ( Msa Sn ) Plating on Plastics (E less Ni, E less Cu, Catalyst, Cu, Ni, Cr+3)

7 Dow Electronic Materials The core competencies, products and application experience that Dow has within its Electronic Materials business is ideally aligned with the requirements of the MID metallization needs Surface preparation Conductor metallization and build up Solderable and corrosion protection finishes

8 MID Applications and Advantages

9 MID Advantages MID is acronym for Molded Interconnect Devices Integrating electrical circuitry and electronic function into a 3-D MID component offers many market segments and applications benefits Design flexibility Improved function Lower cost

10 MID Applications The market is dominated today by the use of MID technology in hand held devices, but growth is also seen in many other segments. Automotive applications for MID have grown significantly in recent years 8% 4% 3% 2% Communication Automotive Medical 83% Micro Packaging Security The design, cost and functional benefits of MID will drive adoption in many other markets and applications Source:LPKF

11 MID Molding Processes Hot Stamping Hot Stamping

12 MID Molding Processes Two-shot Molding Two Shot Molding 3D, fine pitch, high volume application Relatively high costs in molding tools Special thermoplastics required Long development times and limited design flexibility Two polymers are used; one which is plateable, the other non-plateable Shot One Catalyse Shot Two Metallisation

13 MID Molding Processes Laser Direct Structuring (LDS) LDS system advantages Highly functional circuit layouts on complex 3D parts with integrated assembly capability Base materials doped with catalyst which allow selective circuit traces by laser activation and subsequent metallization with electroless copper and final finish plating, such as ENIG Fast prototyping and feedback for product design. Manufacture of small to large volumes, not feasible with alternative MID processes Source:LPKF

14 Process Overview Dow Electronic Materials Metallisation of MID

15 Plating on Plastics (POP) Traditional POP Etch Neutraliser Catalyst Accelerator Electroless Nickel / Copper Used for complete metallisation of base plastic, typically ABS or ABS/PC blends. Adhesion provided by etching / oxidation of base material using chromic acid etching Total surface is catalysed using a Palladium catalyst Total surface is metallised by catalytic reduction of nickel or copper The desired finish is applied by electrolytic deposition of copper, nickel, chrome, silver, gold, etc, depending on the end user requirements Electroplate

16 MID Metallisation 2 Shot Moulding Non-catalysed Material Etch Neutraliser Similar to traditional POP Base material is etched with chromic acid to achieve adhesion sites for subsequent metal deposition Catalyse surface with palladium catalyst Catalyst Second Shot Mould Make second Shot Moulding Metallise exposed catalysed areas using electroless copper Electroless Copper Required protection / finish

17 MID Metallisation 2 Shot Moulding Pre-catalysed Material Etch Neutraliser The use of pre-catalysed base material for the first shot eliminates the need for a chemical catalyst step. The first material in this case has catalyst material embedded in the polymer Second Shot Mould Electroless Copper Required protection / finish Etching the surface using chromic acid etch (or for some polymers, Alkaline Permanganate Etch) to reveal the embedded catalyst Make second Shot Moulding Metallise exposed catalysed areas using electroless copper

18 MID Metallisation LDS Pre-catalysed Material Laser Structure Ultrasonic Clean Electroless Copper The LDS approach eliminates the use of chemical etching to achieve adhesion sites and catalyst exposure. Ultrasonic water washing removes laser debris to reveal the exposed catalyst sites Electroless Copper covers the exposed catalyst and is built up to the customer thickness requirements (5 15um typical) The final finish is applied dependent on the degree of corrosion protection or assembly complexity Required protection / finish Source: LPKF

19 MID Metallisation LDS The selection of final finish depends on the end user environment and assembly requirements Process Function Cu-Ni-(Pd)-(Au) Rinse with Ultrasonics Electroless Copper Acid Pre Dip Catalyst Acid Post dip Electroless Nickel Electroless Palladium Immersion Gold Cu-Ag-(Au) Rinse with Ultrasonics Electroless Copper Electroless Silver Immersion Gold Antitarnish Clean LDS Debris Make features conductive Solderable, bondable, corrosion resistant finish

20 MID Metallisation - Copper Deposition Electroless Copper plating onto catalysed MID materials has been practiced for more than 20 years. However today s range of base materials, processing equipment and end user variables requires careful product selection and operation. Product Selection Uniform coverage and adhesion of base material Too stable or slow can create poor coverage Unstable or too fast can create poor adhesion, blistering or stressed deposits Process Equipment Usually determined by MID size, however handling, design complexity and mechanical damage need to be considered. Vertical rack or basket processing equipment dominates, but barrel processing is used for small parts. Operation and control Electroless copper allows complex parts to be metallised with a uniform copper deposit on all catalysed surfaces, without the need for an electrical current (unlike electroplated copper used for conventional 2-D printed circuits) Maintaining control of coverage, adhesion and deposit quality requires routine analysis, replenishment and functional controls.

21 Copper Deposition The Chemistry Major Components Cupric Ions - Cu2+ Reducing Agent - Formaldehyde (HCHO) Hydroxide - OH- Complexant for Cu2+ - eg. EDTA Stabilizers design overcome non-catalysed Disproportionation 3 reactions which will cause Cu20 + H20 Cu + Cu2+ + 2OH- unwanted plate out if not controlled Electrons from catalysed oxidation of formaldehyde used for reduction of copper Hydrogen evolved must be vented effectively equipment and rack design to avoid gas build up Stabilisers, air and equipment Overall Reaction Cu2+(comp) + 2HCHO + 40H- Cu + 2HCOO- + H2 + 2H20 Catalyst initiates oxidation of Formaldehyde Half Reactions 1 2HCHO + 40H- 2HCHCOO- + 2H20 + H2 +2e- Cu2+(comp) + 2e- Cu + (comp) 1 Initial Catalysation HCHO + 30H- HCOO- + 2H20 + 2e- Continued Catalysation 2 2HCHO + 40H- 2HCOO- + 2H20 + H2 + 2e- This reaction is necessary to allow deposition to build up on copper surface. Fehling s 2Cu2+ + HCHO + 50H- Cu20 + HCOO- + 3H20

22 MID Metallisation - Final Finish A final finish is then applied to the copper conductors. The choice of finish being dependent on the requirements of the OEM, application or function. ENIG - Electroless Nickel, Immersion Gold has been the most common finish, offering corrosion protection of the copper as well as a flat solderable surface. Although simple corrosion protection of copper often uses electroless nickel only. Cu Base Material ENIG Au Ni Cu Base Material DURAPOSIT SMT88 Electroless Nickel and AUROLECTROLESS SMT Immersion Gold are used to deposit the final finish, of approx. 5um nickel and 50nm gold, providing the MID with a long shelf life, protecting the underlying copper from corrosion and providing a solderable surface This metallisation process is usually conducted in a vertical basket line, but barrel plating of smaller parts is also typical

23 MID Metallisation - Final Finish ENEPIG, using an electroless palladium barrier between nickel and gold is favoured by those seeking higher reliability, since the palladium layer prevents corrosion of the nickel (and hence prevents any related solderability issues). This ENEPIG finish is also gold wire bondable. Whilst ENEPIG is more capable and ENIG, the cost is also higher. Cu Base Material ENEPIG Au Pd Ni Cu Base Material DURAPOSIT SMT88 Electroless Nickel, PALLAMERSE SMT2000 Electroless Palladium and AUROLECTROLESS SMT Immersion Gold are used to deposit this final finish, of approx. 5um nickel, 0.2um palladium and 30nm gold. In addition to the ENIG benefits, the surface is now wire bondable and the nickel is not corroded by the gold. This metallisation process is typically conducted in a vertical basket line

24 MID Metallisation - Final Finish ASIG Autocatalytic Silver, Immersion Gold, is a new final finish, used either as silver only, or with silver and gold. This avoids the use of nickel (and any related corrosion concerns) as well as providing excellent RF performance (eg. Antenna) ASIG finish is suitable for gold and aluminium wire bonding Cu Base Material Au Ag Cu ASIG Base Material SILVERON MF100 Autocatalytic Silver is used to deposit this final finish, of approx. 0.2um silver. This finish avoids the use of nickel and gold (although gold can be applied onto the silver where gold wire bonding is required). This metallisation process is typically conducted in a vertical basket line

25 MID Metallisation Factors to Consider MID Method Complexity, Cost, etc Two Shot LDS Base material choice Design, Function, Cost Process Settings Component Size Number of components Equipment Type Rack, Barrel Basket Copper thickness Process times End Use, Current, Hz, etc Copper thickness, adhesion, etc Assembly requirements Corrosion protection Soldering, Shelf life, etc Nickel, Gold, Silver, etc

26 MID Metallisation Plating Equipment Basket Manual handling Mechanical damage risk Parts size Medium Low Medium to large Rack Manual handling Mechanical damage risk Parts size High Low Small to Large Barrel Manual handling Mechanical damage risk Parts size Low High Small

27 MID Metallisation - Plating Process Process equipment Available plating equipment for MID plating from many suppliers, designed to customer requirements From simple manual lines, to large automatic lines Small manual plating lines for LDS-MID plating from ca. 30k to large automated lines > 500k Process capacity Electroless copper will deposit copper at approximately 3µm / hour Selection of racks / jigs for MID handling and optimum loading is dependent of the size and shape of the MID Process output can be optimised for small to large volumes Environment Complying with local authority and government regulation for the use, handling and disposal of chemicals and waste water requires careful consideration (copper, nickel, formaldehyde, etc) Subcontract plating is available through many established companies who specialise in plating Industry 3D-MID e.v. Association provides a framework for support and development of MID technology through it s diverse membership covering all aspects of MID design, manufacture and assembly

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29 Summary Design and build of electronic devices using LDS-MID technology is now a major, proven, cost effective alternative to conventional interconnection methods, offering designers, manufacturers and end users benefits and future opportunities Selection of the most appropriate base materials, electroless copper, final finish and processing equipment is essential to ensure optimum performance, quality and cost. Whilst the current process is proven in many markets and in volume production, Dow Electronic Materials continues to invest in research and development to ensure that this growing market is served with products that continue to offer function and value matched to market demands.

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