Cu 2 O deposition Process

2 Rhodia Kermel Summary Concept presentation Technical requirements Process description Advantages

3 Rhodia Kermel This new technology relies on the existence of cuprous oxide (Cu 2 O) in the substrate, which allows the metallization of the surface. The particles of Cu 2 O are distributed in the resin which constitutes the substrate to be metallized at the rate of 2,5 to 10 % in volume. Its transformation into pure metal, Cu°, only operates at the surface and in the micro-holes, when exposed to the contact of a specific chemical reducing agent, a borohydride, following the global reaction : This reduction converts a discrete distribution of Cu 2 O particles into a continuous metallic copper layer which can be reinforced by both electroless and electrolytic processes up to the required thickness. Plating process : Concept presentation 4 Cu 2 O + BH 4 -  8 Cu° + B(OH) 3 + OH - K + BH 4 - Cu 2 O particle Resin Cu metal layer

4 Rhodia Kermel Plating process : Concept presentation Products and operation for the process application : Cu 2 O particles :  pulverulent powder, can be refined, dispersed within the polymeric matrix,  cheap and usual product,  several suppliers. Chemical treatment before the reduction to remove the superficial layer of the matrix :  to achieve high level of peel strength (see photo 1 next page),  to metallize simultaneously holes and surfaces (see photo 2 next page). Reducing agent : mainly potassium or sodium borohydride  usual (several suppliers) and low cost (much cheaper than palladium),  easy to handle (not hazardous, in an aqueous form),  easy to use : at first sight, borohydride solution can be substituted to palladium batch in the standard process line. Optimization to fit the wanted requirement:  concentration, size and dispersion of Cu 2 O particles,  chemical treatment before reducing,  reduction’s parameters.

5 Rhodia Kermel Plating process : Concept presentation Photo 1 : Interface between the substrate and the copper obtained after a chemical treatment Photo 2 : Very good peel strength continuity for the metal layer in surface and holes thanks to reduced Cu 2 O particles

6 Rhodia Kermel PCB prototype that has been obtained through the Cu 2 O Plating Process Size of the conductor line : 10 µm. Plating process : Concept presentation

7 Rhodia Kermel The Cu 2 O plating process is protected by 6 patents covering both laser and photovia drilling Internal patent number International patent numberAbstract R France, USA, OEB (DE, BE, GB, IT, NL, SE, IR), Japan.Organic substrate metallization process using small filler particles of dispersed non conductive oxide R France, USA, OEB (DE, AT, BE, SP, FR, IR, IT, LU, NL, GB, SE, CH), Canada, Korea, Japan, Taiwan, Israel, South Africa, Australia. Metallization process of thermostable films by reducing copper oxide with borohydride followed by electrolytical deposition Plating process : Concept presentation R OEB (DE, AT, BE, SP, FR, IR, IT, LU, NL, GB, SE, CH) Canada, USA, Korea, Japan, Taiwan Israel, South Africa, Australia. Electrically insulated polymeric film metallization by reducing metal oxide particles with borohydride followed by electrolytical deposition R France, USA, OEB (DE, AT, BE, FR, GB, IT, LU, NL, SE, CH), Spain, Canada, Taiwan, Korea, Japan. Possibility of using both isotropic metallizable polymeric substrates with low CTE and resin including metal oxide particles

8 Rhodia Kermel The Cu 2 O plating process has been developed in the eighties by Rhône Poulenc and suspended for strategic reasons in the nineties. Plating process : Concept presentation Internal patent number International patent numberAbstract R French patent deposit before international extensionCompatibility of laser drilling with metallization process using reduced copper oxide with borohydride followed by electrolytical deposition R French patent deposit before international extensionCompatibility of photovia drilling with metallization process using reduced copper oxide with borohydride followed by electrolytical deposition 2001 Patents in progress

9 Rhodia Kermel Concept presentation Technical requirements Process description Advantages

10 Rhodia Kermel Three requirements have been tested so far highlighting the potential of the Cu 2 O metallization process. Plating process : Technical requirements Laser drilling possibility Peel strength potentially exceeding market requirements Dielectric constant features fitting market requirements Technical compatibility 1 2 3

11 Rhodia Kermel Cu 2 O particles do not hinder the laser drilling quality. Non optimized laser drilling tests for Epoxy + Cu 2 O Source: Delta Electronic services Cu 2 O weight concentration: 60 % in volume: 10 % Plating process : Technical requirements

12 Rhodia Kermel Dielectric properties are slightly modified by the Cu 2 O particles and even improved in certain cases Note: (1) In weight percentage Properties Superficial resistivity (  / ) Volume resistivity (  /cm) Dielectric constant Dk (1 MHz) Dissipation factor Df (1 MHz) ,9 0,019 Epoxy 3, , ,8 0,018 Cu 2 O 22% (1) Measures on ~ 1,6mm laminates Plating process : Technical requirements

13 Rhodia Kermel When initial chemical surface treatments are done, peel strength potentially exceed market expectations. Treatment types n Treatment 1: Permanganate or bichromate chemical treatment. At the end of the treatment, necessity to eliminate chromium or manganese oxides thanks to hydroxylamine chlorohydrate or sulphate. n Treatment 2: Alkaline chemical treatment in hydroalcoolic environment. Potash: 350g; methanol/ethanol/water: 400cm 3 /50cm 3 /10cm 3 Temperature: 80°C. Peel strength fluctuating according to parameters (epoxy type, particle size and dispersion (3), physicals conditions,…). Surface peel strength (1) for Cu 2 O + epoxy kg/cm Notes:(1) Tests realized ten years ago (2) 1,4 kg/cm = 8 lb/inch (3) Concentration between 10% to 50% in weight percentage Sources: Kermel, Rhône Poulenc Treatment 1 Treatment 2 Norm (2) Plating process : Technical requirements

14 Rhodia Kermel With regard to peel strength, Cu 2 O plating process offers several potential advantages Kermel's plating process using Cu 2 O particles reduced with borohydride Potential advantages Very good peel strength continuity in surface and holes thanks to Cu (reduced Cu 2 O) Increased peel strength compared to standard epoxy thanks to Cu 2 O particles anchored inside the resin Peel strength level modularity through control of concentration and dispersion of Cu 2 O particles Recycling possibility in case of non satisfactory level of metallization Plating process : Technical requirements

15 Rhodia Kermel Concept presentation Technical requirements Process description Advantages

16 Rhodia Kermel Plating process : Description  At first sight, in the SBU layer production process, minor changes should occur in major PCB makers production lines to implement the Cu 2 O metallization concept. Changes occur principally in 2 steps : - drilling when compared to RCC (see step 4 of the process chart), - electroless plating with a substitution of the palladium by the borohydride reduction bath (see step 5).  With the Cu 2 O metallization concept, the number of the process steps is : - 25% less than RCC technology, - the same than liquid technology.  SBU layer simplified production steps with CO 2 laser drilling and with different elaborated materials is presented in the 4 next slides.

17 Rhodia Kermel Note: (1) Process with window creation Plating process : Description Stoving Stacking Pressing, heating Disassembling/cleaning Coating Drying/heating Coating Drying/heating Copper clad Cu 2 O particles Half etching Rinsing  Core preparation  Build-up deposition (coating/ lamination)  Surface treatment Stoving Stacking Pressing, heating Disassembling/cleaning Copper line Dielectric Upper core layer RCC (1) Epoxy/polyimide + Cu 2 OLiquid resin Production steps Dry film SolidsLiquids Micro-etching Rinsing Black oxydation Surface treatment Rinsing Surface treatment Rinsing Surface treatment Rinsing SBU layer simplified production steps with CO 2 laser drilling and with different elaborated materials

18 Rhodia Kermel Note: (1) Process with window creation Plating process : Description Etching Rinsing Photoresist stripping Copper oxydation Rinsing à Drilling Surface preparation Photoresist deposit Insulation Development Rinsing Photoresist "window" CO 2 drilling Etch back Rinsing CO 2 drilling Etch back Rinsing CO 2 drilling Etch back Rinsing "Laser" resin CO 2 drilling Etch back Rinsing "Laser" resin RCC (1) Epoxy/polyimide + Cu 2 OLiquid resin Production steps Dry film SolidsLiquids SBU layer simplified production steps with CO 2 laser drilling and with different elaborated materials

19 Rhodia Kermel Plating process : Description Note: (1) Process with window creation Switch the palladium deposit bath by a borohydride reduction bath Degreasing Rinsing Pre-catalysis Catalysis Activation Degreasing Rinsing Pre-catalysis Catalysis Activation Thin chemical copper deposit Rinsing Fastened thick chemical copper deposit Rinsing Thin chemical copper deposit Rinsing Ä Electroless plating Å Image transfer Chemical plating Palladium Photoresist Surface preparation Photoresist deposit Insulation Development Rinsing Degreasing Rinsing Pre-catalysis Catalysis Activation Thin chemical copper deposit Rinsing Surface preparation Photoresist deposit Insulation Development Rinsing Photoresist RCC (1) Epoxy/polyimide + Cu 2 O Liquid resin Production steps Dry film SolidsLiquids Surface reduction with potassium borohydride Rinsing Copper Fastened thick chemical copper deposit Rinsing Epoxy/polyimide + Cu 2 O Surface reduction with potassium borohydride Rinsing Copper SBU layer simplified production steps with CO 2 laser drilling and with different elaborated materials

20 Rhodia Kermel Plating process : Description Note: (1) Process with window creation SBU layer simplified production steps with CO 2 laser drilling and with different elaborated materials Etching Rinsing Differential etching Rinsing Differential etching Rinsing Differential etching Rinsing Æ Electrolytical plating Ç Etching Copper deposit Rinsing Photoresist stripping Rinsing Copper deposit Rinsing Photoresist stripping Rinsing RCC (1) Epoxy/polyimide + Cu 2 OLiquid resin Production steps Dry film SolidsLiquids

21 Rhodia Kermel Concept presentation Technical requirements Process description Advantages

22 Rhodia Kermel Plating process : Advantages This new plating process is : Easy to implement - Process gets simultaneously plated holes and surfaces. - Products are usually cost competitive and easy to handle (Cu 2 O and borohydride). - Number of process steps reduced. - Compatibility with liquid/film technologies. Reliable - Due to the high level of peel strength achieved. - Peel strength of plated copper increased in surface and in micro-via holes. Technologically advanced - Reliable access to additive/semi additive processes. - Reliable access to fine line. - The presence of Cu 2 O particles, compatible with the dielectric and CTE requirements, enhance the thermal transfer of dielectric matrix. Economic - Reliability and more specifically of plated micro-holes. - Saving of labor because of less steps and operations. - Saving of investment because minimum changes in production lines for PCB makers.

23 Rhodia Kermel As a conclusion, the Cu 2 O Plating Process is easy to implement, technologically advanced, and above all, reliable and economic. In that way, our innovative plating technology : comes up to current specifications and even exceeds the market expectations, answer potentially to the evolution in specifications, is adaptable to most industrial processes. For more information, please contact : V. LORENTZ Marketing Department Tel : + 33 (0) Fax : + 33 (0) Plating process : Conclusion