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Photopolymerized Conducting Polymers

Morziana Hasan

#12346

Photopolymerized Conducting Polymers | 10 March, 1999

NASA CommQuest

Photopolymerized Conducting Polymers

Directions: 1.Please read the information provided on this technology. You may follow the links to additional information resources below.

2.After evaluating the technology, please answer the questions below to the best of your ability

Technology Description High-quality, electronically conducting organic polymer films can be made by a new photopolymerization process. This results in a new additive direct metallization process which has a number of potential applications in the electronics industry: A new additive, or partially additive, method for printed wiring board (PWB) manufacturing; Formation of passive elements such as resistors and resistor networks in PWB and MCM industry, and; Repair of damaged, or addition of new, conducting patterns on finished electronics products.

Photopolymerization Process The process utilizes a simple ink-like formulation that consists of a pure monomer (pyrrole, aniline), a salt and a solvent. The salt serves both as an electron acceptor for oxidation of the monomer and as a dopant to preserve electroneutrality in the oxidized polymer. A novel photolithographic method for the synthesis of conducting polymer films uses UV lamp flood exposure, argon-ion laser or electron beam as the driving force to induce electron transfer from monomer species in a cast solution film to the electron acceptor, also present in the formulation.

The photopolymerization process does not require a conducting substrate for deposition to take place, and conducting polymer films and/or lines of various thickness can be readily photopolymerized on typical printed wiring board (PWB) substrates (fiberglass/epoxy, polyimide) and multichip modules (MCM) substrates(alumina) as well as on metals, silicon, GaAs, glass, paper, Teflon, Mylar and polystyrene substrates.

The photopolymerization process can be easily modified to yield conductive polymer films with controlled resistivity by varying the composition of the photopolymerizable solution. Polymer adhesion, flexibility, and speed of curing can be adjusted by incorporating additives into the photopolymerizable solution, such as flexibilizers, photoinitiators and adhesion promoters.

PWB and MCM Metallization The photopolymerization method for the preparation of conducting polymer films can be applied to PWB manufacturing as an additive direct metallization process.

The process eliminates environmentally undesirable electroless copper plating and significantly reduces the number of PWB manufacturing steps. The developed direct metallization process is highly efficient and has the potential to satisfy the criteria required for designing future PWBs:(i) environmentally conscious manufacturing, & (ii) high-resolution conductor line imaging.

A proprietary electroplating apparatus has also been developed for electroplating developed conducting polymer patterns which can also find applications in other direct metallization processes. This method allows for electroplating and not only electroless plating in direct metallization processes.

The developed metallization process is capable of simultaneously plating through-holes and conducting patterns on PWB (or MCM) substrates.

Formation of Passive Electronic Elements The main advantage of the photopolymerization process for the preparation of conducting polymers is that it allows the properties of conducting polymer films to be easily modified by optimizing the starting photopolymerizable formulations. The conductivity of the polymer films is controlled by varying the amount of the electron acceptor (silver nitrate) and co-monomers, e.g., aniline, present in the formulations. The resistivity of the conducting polymer films can be changed over several orders of magnitude by simply varying the concentration ratio of starting components in the formulation. The work toward optimization of the formulations and achieving resistors with low values in the range 10 -1,000 ? is in progress.

Benefits and Advantages Photopolymerized conducting polymer films with properties that can be easily adjusted to improve the PWB metallization process and quality of resistors. Minimization of hazardous chemicals and copper plating solutions; No environmentally problematic electrodless-copper plating and etching process needed; Significant reduction in the number of PWB or resistor manufacturing steps; Industrially scaleable processing method that readily lends itself to automated manufacturing; and Cost-effective and environmentally benign technology.

Additional Resources Patent Document Technology Opportunity Sheet Article: Machine Design Magazine, September 12, 1996 "Magnetic Slip ring transmits power through air"

Question 1: What new or existing applications or products could benefit from this technology?

Question 2: Could this technology provide any value or benefits to your industry?

Question 3: Do you have any other additional comments, suggestions, or questions?

Name *

Email Address *

Company or Organization Affiliation *

Title or Position *

Thank you for your input!

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Justin Medernach

#12347

Cool technology, minimal applications | 11 March, 1999

| NASA CommQuest | | | Photopolymerized Conducting Polymers | | Directions: | 1.Please read the information provided on this technology. You may follow the links to additional information resources below. | | 2.After evaluating the technology, please answer the questions below to the best of your ability | | | Technology Description | | High-quality, electronically conducting organic polymer | films can be made by a new photopolymerization process. This results in a new additive direct metallization process which has a number of potential applications in the electronics industry: | | A new additive, or partially additive, method for printed wiring board (PWB) manufacturing; Formation of passive elements such as resistors and resistor networks in PWB and MCM industry, and; | Repair of damaged, or addition of new, conducting patterns on finished electronics products. | | Photopolymerization Process | The process utilizes a simple ink-like formulation that consists of a pure monomer (pyrrole, aniline), a salt and a solvent. The salt serves both as an electron acceptor for oxidation of the monomer and as a dopant to preserve electroneutrality in the oxidized polymer. A novel photolithographic method for the synthesis of conducting polymer films uses UV lamp flood exposure, argon-ion laser or electron beam as the driving force to induce electron transfer from monomer species in a cast solution film to the electron acceptor, also present in the formulation. | | The photopolymerization process does not require a conducting substrate for deposition to take place, and conducting polymer films and/or lines of various thickness can be readily photopolymerized on typical printed wiring board (PWB) substrates (fiberglass/epoxy, polyimide) and multichip modules (MCM) substrates(alumina) as well as on metals, silicon, GaAs, glass, paper, Teflon, Mylar and polystyrene substrates. | | The photopolymerization process can be easily modified to yield conductive polymer films with controlled resistivity by varying the composition of the photopolymerizable solution. Polymer adhesion, flexibility, and speed of curing can be adjusted by incorporating additives into the photopolymerizable solution, such as flexibilizers, photoinitiators and adhesion promoters. | | PWB and MCM Metallization | The photopolymerization method for the preparation of conducting polymer films can be applied to PWB manufacturing as an additive direct metallization process. | | The process eliminates environmentally undesirable electroless copper plating and significantly reduces the number of PWB manufacturing steps. The developed direct metallization process is highly efficient and has the potential to satisfy the criteria required for designing future PWBs:(i) environmentally conscious manufacturing, & (ii) high-resolution conductor line imaging. | | A proprietary electroplating apparatus has also been developed for electroplating developed conducting polymer patterns which can also find applications in other direct metallization processes. This method allows for electroplating and not only electroless plating in direct metallization processes. | | The developed metallization process is capable of simultaneously plating through-holes and conducting patterns on PWB (or MCM) substrates. | | Formation of Passive Electronic Elements | The main advantage of the photopolymerization process for the preparation of conducting polymers is that it allows the properties of conducting polymer films to be easily modified by optimizing the starting photopolymerizable formulations. The conductivity of the polymer films is controlled by varying the amount of the electron acceptor (silver nitrate) and co-monomers, e.g., aniline, present in the formulations. The resistivity of the conducting polymer films can be changed over several orders of magnitude by simply varying the concentration ratio of starting components in the formulation. The work toward optimization of the formulations and achieving resistors with low values in the range 10 -1,000 ? is in progress. | | Benefits and Advantages | Photopolymerized conducting polymer films with properties that can be easily adjusted to improve the PWB metallization process and quality of resistors. | Minimization of hazardous chemicals and copper plating solutions; No environmentally problematic electrodless-copper plating and etching process needed; | Significant reduction in the number of PWB or resistor manufacturing steps; | Industrially scaleable processing method that readily lends itself to automated manufacturing; and | Cost-effective and environmentally benign technology. | | | Additional Resources | Patent Document | Technology Opportunity Sheet | Article: Machine Design Magazine, September 12, 1996 "Magnetic Slip ring transmits power through air" | | Question 1: What new or existing applications or products could benefit from this technology? | | Question 2: Could this technology provide any value or benefits to your industry? | | Question 3: Do you have any other additional comments, suggestions, or questions? | | Name * | | Email Address * | | Company or Organization Affiliation * | | Title or Position * | | Thank you for your input! | I'm going to play devil's advocate on this technology. I see limited use for this additive process. First of all, handling becomes so critical. As with any additive conductive in "trace", a scratch eliminates the connection. That scratch can occur anywhere in the process. Another difficulty is the cost. You mentioned that there are costly processes which are avoided and also environmental hazards that are removed from the equation. However, this is still an additive process, thusly incurring more cost. A main concern is what happens to it while it's in process. We stencil print our boards on contact. The squeegee is applying roughly 7kg of pressure depending on the blade length. This pressure is, theoretically, applied directly to the substrate e.g. the conductive trace or feature. The trace will be damaged occasionally because of this process alone. The fix is a very specialized stencil that has "tracks" etched into it, accounting for the conductive feature. This process requires a pretty darn good stencil supplier. Where do I see merit in this process? It's probably in the high rel, low volume product that would cost an arm and a leg to retool at a fabricator. It's no fun to find out that a $4000 bare board is no good because of a design error. Conductive inks allow for the Mfr. to avoid some costly scrap but should not be used as a primary design symbol due to the concerns in assembly.

You have my two cents.

Regards, Justin Medernach Mfg. Eng. Flextronics International Product Introduction Center East 978 392 3218

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