More than 20 years ago, material manufacturers were competing  to develop adhesiveless copper-clad laminates for next-generation flexible circuits.

A dozen or so companies were leaders of the pack with their new technologies. These technologies were categorized two types: casting/laminating process, and a metallization of polyimide films.

The casting/lamination process used couple of polyimide resins coated on copper foils and baked to form a reliable base layer. Next, a second copper foil was laminated on the other side of the polyimide layers. The process provided reliable bond strength between base film and copper, but the manufacturing process was complicated, and the cost was relatively high.

Metallization of the polyimide film required the production of a seed layer before electrical plating. The two choices to produce the thin seed layer were a sputtering in a vacuumed chamber or electroless plating in a wet bath. The sputtering created reliable bond strength, but the process is slow and expensive. Electroless plating is a simple process and it provided a low-cost solution, but unstable bond strength was an issue.

There was no perfect manufacturing process; each had advantages and disadvantages. At the time, I was a project leader for a manufacturer of casting-type adhesiveless laminates. The manufacturing facility was subpar, and did not have enough capabilities to satisfy customer requirements. I needed to change our business strategy. First, I reorganized the R&D engineering staff to focus on engineering services for small-volume customers that required high-end applications. Simultaneously, I required our process engineers to improve quality and yields. The strategy was successful! We acquired strategic customers with high-volume applications and increased our margins. Our products became the industry standard.

The metallized laminates with sputtering did not garner much support in the flex circuit industry. It is still popular as a special application for driver IC modules in flat panel displays. The modules require very fine traces; accordingly they demanded very-thin copper foils. The devices were inexpensive and the market grew rapidly. The sputtered laminate became the industry standard.

Unfortunately, metallized laminate with electroless plating was not successful even though the process was inexpensive. Manufacturers could not improve the bond strength significantly enough, and the process is no longer used in the industry.

I developed a new metallization processes comparing sputtering and electroless plating for medical devices. Both technologies improved significantly over the past 10 years. They have different advantages, and I use them both, depending on the application. They can metallize on polyimide films as well as new exotic materials such as rubber sheets, paper, cloths and more, and are a comfortable dielectric material for wearable electronic devices.

Can the metallization processes generate a new flexible laminate business for wearable devices? Absolutely! Feel free to reach out to DKN Research for a collaborative project centered on wearable electronics.

Dominique K. Numakura, This email address is being protected from spambots. You need JavaScript enabled to view it.

DKN Research,

DKN Research Newsletter #1832, December 9th, 2018 (English Edition) (Micro Electronics & Packaging)

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Headlines of the Week

1. ELIIY Power (battery manufacturer in Japan) developed a new lithium ion batter with nonflammable ion liquid.

2. AIST (major R&D organization in Japan) developed a new anode material of SiO deposited by vacuumed evaporation for lithium ion batteries. It makes battery capacity five times larger compared to the traditional graphite anode.

3. NTT (major telephone company in Japan) demonstrated a prototype model of flexible and transparent secondary battery for IoT applications.

4. AGC (major glass product supplier in Japan) developed a glass base transparent antenna for 28GHz band 5G telecommunications targeting windows of automobiles and buildings.

5. JAE (major connector manufacturer in Japan) rolled out a waterproof connector series “MX60A” for use in automobile engines. The pin count is up to 177.

6. DaiShinku (vacuum equipment manufacturer in Japan) developed the industry's smallest-size quartz device with embedded temperature sensor in the package. Package size: 1210 (1.2 x 1.0 x 0.5 mm)

7. Toshiba will roll out a compact 3.5” HDD with 14Tb capacity for consumer applications in February.

8. Yasukawa (major robot manufacturer in Japan) unveiled its new manufacturing plant “Yaskawa Solution Factory” with various IoT technologies. The productivity will be three times higher, and the lead-time will be one-sixth.

9. Ricoh is introducing “New Deep Learning Process” for robotics using GAN (Generative Adversarial Network). It imitates actions of human beings.

10. Takenaka (major construction company in Japan) is introducing drones to check the progress of the constructions in the limited space in high density building areas.

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