Copper Laminates Made From Transparent Polyimide Films Now Available


Reading time ( words)

Significant progress has been made over the last few years in building transparent and heat resistant flexible circuits. Several transparent materials were developed along with special manufacturing processes. A copper laminate made from a thin transparent polyimide file plated with a copper layer on both sides for use in traditional manufacturing processes is now available. DKN Research developed a new copper metalizing process using transparent polyimide films. The new laminate will provide manufacturing capabilities using transparent flexible circuits for traditional printed circuit manufacturers.

Polyimide films are the primary substrate material for heat resistant flexible circuits because of the balanced performances between heat resistance and physical properties. The problem is they tend to have an orange or brown color, so the film’s transparency is very low. This is a huge barrier for any optical applications. PET films are another popular substrate material for transparent flexible circuits, but their heat resistance is too low and will not work in standard assembling processes such as soldering and wire bonding. A couple of new heat resistant resins such as LCP have been synthesized and are considered the next generation material for flexible circuits; however, they may not be transparent either. Many chemists used to question the availability of a product that is both transparent and heat resistant. That has changed. Several chemists were successful in synthesizing transparent polyimide resins, and a few companies have brought to market some thin transparent polyimide films that serve as the substrate for heat-resistant flexible circuits.

There are still a few technical hurdles in building transparent flexible circuits. The biggest one is the availability of an appropriate copper laminate for the standard photolithography/chemical etching process. Some of the copper laminates had problems with the surface treatment and gluing of the copper. The transparency of the circuits was remarkably reduced by absorption and scattering.

DKN Research developed a total solutions package for transparent flexible circuits based on each application. During the R&D process, DKN Research has established an electroless and electroplating process of nickel, copper and gold on the transparent polyimide films that provides thin copper laminates available for the standard photolithography/etching process of high density flexible circuits. The new copper laminate could be valuable for traditional flexible circuit manufacturers, because the new laminate does not need any additional equipment or chemicals to build transparent flexible circuits. The transparency of the circuits can be over 85%.

The standard construction of the laminate uses double-sided 3-micron thick copper layers on a 25-micron thick transparent polyimide film. The copper thickness can be thinner at 0.2 microns, and wider thickness ranges will be available for circuit manufacturers. The thin copper conductor could be valuable for semi-additive processes for ultra-fine flexible circuits with microvia holes in the transparent flexible circuits. DKN Research will provide free laminate samples along with a processing guide to circuit manufacturers.

DKN Research will upgrade the laminates and process capabilities to build the leading edge flexible circuits. DKN Research is happy to share the materials and information with circuit manufacturers and device manufacturers. Click here to view a short clip about their products and services. 

About DKN Research

DKN Research is a global engineering leader for microelectronics and packaging, specializing in printable & flexible electronics. DKN Research has developed a broad range of leading edge technologies from materials to final devices based on customers’ requirements. They are capable of managing many kinds of materials and manufacturing processes to build and create new devices based on customer needs.

DKN Research provides a broad range of engineering and consulting services not only for the manufacturing community but also the R&D and quality assurance professionals. DKN Research welcomes all inquiries to assist in creating your own circuit devices using its broad range of processing technologies.

Share




Suggested Items

Lessons Learned: Breaking Down the Four Types of Communication

10/11/2022 | Nolan Johnson, PCB007 Magazine
Kelly Dack and Nolan Johnson explore the silver linings from the past two years, especially the importance of good communication. These skills are—as they have always been—key to the success of the project. But how do you define the best methods for communication? Kelly breaks down four personality types and why it’s important to recognize how one person differs from another. When you better understand how a person thinks, your level of effective communication increases exponentially.

EIPC Technical Snapshot: Novel Laser-based Manufacturing Processes in Automotive Electronics

09/22/2022 | Pete Starkey, I-Connect007
“Summer is over, now it's back to work!” This was the opening line of the invitation to the 18th EIPC Technical Snapshot webinar, Sept. 14, following the theme of advances in automotive electronics technology, introduced and moderated by EIPC President Alun Morgan. The first presentation, entitled "The fully printed smart component—combining additive manufacturing and sensor printing," came from Jonas Mertin, a thin-film processing specialist at the Fraunhofer Institute for Laser Technology.

I-Connect007 Editor’s Choice: Five Must-Reads for the Week

07/08/2022 | Nolan Johnson, I-Connect007
In more than one conversation while discussing the industry this week, the themes have included industry turmoil, lots of business opportunities, and the urgent need to build out to meet changing demands. In fact, our July issue of PCB007 Magazine, which publishes later this month, will focus on these very topics. It’s definitely one not to be missed! These themes also emerged in this week’s top five news items as well. Top stories include an acquisition in the soldering machinery space, sales and service expansion in Mexico, industry data from SIA on semiconductor global sales data, and strong financial numbers from two China-based manufacturers. Now, with the U.S. Congress putting its focus on the PCB industry, things could really heat up. It’s going to be an interesting year.



Copyright © 2022 I-Connect007 | IPC Publishing Group Inc. All rights reserved.