HIRATSUKA, Japan – Japan’s electronics industry is floundering. For examples, look no further than Toshiba’s never-ending drama over sales of its NAND flash business, and Foxconn’s takeover last year of LCD giant Sharp.

Time to write off Japan? Perhaps, but first a number of undervalued gems buried beneath the surface of Japanese big business. 

Any hunt today for a hot electronics business or promising electronics technologies in Japan has to round up more than the usual suspects, like Toshiba, Sony or NEC. Many of the old-guard electronics companies, as a matter of survival, have sold off or folded their sprawling R&D projects or budding business units.

The first step in finding Japan’s diamonds in the rough is to seek out corporations whose main business is not in electronics. 

Toray Industries Inc., for instance, is primarily known for textiles. In recent years, however, Toray has diversified into electronic circuit- and semiconductor-related materials and optical filters for flat panel displays. It has made itself into something of a powerhouse in nanofibers, carbon fiber component materials, and a microstructure control technology called Nanoalloy. 

Komatsu dump truck
Komatsu dump truck

Komatsu Group, Japan’s big construction and mining equipment company, is branching out in similar fashion. A 100-percent subsidiary of Komatsu called Kelk is a quiet force behind the thermoelectric modules deployed in optical communication infrastructure and semiconductor manufacturing equipment. Kelk, who exhibited for the first time at CEATEC Japan last week, is also promoting its new thermoelectric generator for the emerging IoT/energy harvesting market.

While many large Japanese electronics companies appear to have faltered in the global market, a number of small to medium-sized firms are still equipped with world-class expertise in unique materials for electronics, manufacturing skills in precision components and energy-efficient modules.

Kelk is just one of those companies.

Thermoelectric device

Hiroaki Takechi
Hiroaki Takechi

As Hiroaki Takechi, CEO and president at Kelk, told us, his company’s thermoelectric module business wouldn’t have existed today without the R&D investment made by Komatsu in the 1950s. That’s when Komatsu researchers discovered bismuth telluride (BiTe), which is, said Takechi, essentially “a semiconductor.” When BiTe is alloyed with antimony or selenium, it becomes an efficient thermoelectric material for cooling (refrigeration) or power generation.

The thermoelectric effect is the direct conversion of temperature differences to electric voltage and vice versa. The Seebeck effect is the conversion of heat directly into electricity at the junction of different types of wire. Meanwhile, the presence of heating or cooling at an electrified junction of two different conductors is known as the Peltier effect.

Thermoelectric cooling uses the Peltier effect to create a heat flux between the junction of two different types of materials. Its main application, thus far, is refrigeration, but it can also be used as a temperature controller that either heats or cools.

A thermoelectric circuit composed of materials of different Seebeck coefficients (p-doped and n-doped semiconductors), configured as a thermoelectric generator.
A thermoelectric circuit composed of materials of different Seebeck coefficients (p-doped and n-doped semiconductors), configured as a thermoelectric generator.

Komatsu’s thermoelectric module business, launched within Komatsu’s labs, was spun off in 1966. It became a wholly owned subsidiary, Komatsu Electronics, in 1972, and changed its name to Kelk in 2008.

Semiconductor manufacturing equipment
Kelks’ thermoelectric modules have ridden a wave in the growing market for semiconductor manufacturing equipment. The thermoelectric module that can precisely control temperature — keeping it consistent — has become indispensable for various stages of semiconductor production. 

Kelk’s modules serve the process from washing wafers and photo-resist coating to developing (the wafers are uniformly covered with a developing solution to develop the mask patterns) and removing photo resist. Kelk recently finished work on thermoelectric modules for “etching,” and is currently developing another for “exposure.”

Thermoelectric modules reside at the heart of CMP to control high-temperature chemicals. Thermoelectric modules are also used when washing wafers, to stabilize temperatures in chemical liquids and pure water.  
 Takechi also cited the example of coater/developers, where it’s critical to maintain the uniform temperature of a hot plate onto which a wafer is placed. 

According to Takechi, throughout the coater/developer process, wafer temperature can’t be allowed to vary more than 0.1 C degree. To increase throughput speed, it’s necessary to substantially shorten cooling time — from 120 C degree to 90 C degree, for example. 

The market of thermoelectric modules sounds like a pretty narrow niche in the context of the entire chip industry. But it’s a “high-tech niche,” as Takechi notes, that has earned Kelk a higher product margin and a global reputation. Semiconductor manufacturing equipment vendors depend on Kelk’s thermoelectric modules. Takechi claims Kelk supplies well over 65 percent of thermoelectric modules used in semi equipment on the global market. 

Optical communications
Another notable market for thermoelectric cooler (TEC) temperature controllers is fiber-optic lasers. 

Consumers’ insatiable appetite for increased bandwidth has resulted in deployment of fiber optic-based networks. Fiber-optic lines, driven by solid state lasers, are capable of very high information density. Highly packed data schemes such as DWDM (dense wavelength division multiplexing) use multiple lasers through fiber to obtain large multi-channel data streams.

Narrow-channel spacing relies on laser wavelength that’s tightly controlled. Lasers can do this, but problems come with temperature variations. That’s where TEC temperature controllers come in. 

A temperature controller must meet some unusual requirements. Most notably, because of ambient temperature variation and laser operation uncertainties, it must be able to either source or remove heat. 

Erbium-doped fiber amplifiers are essential to long-range optical-fiber communications, as they can efficiently amplify light. To amplify a laser and prolong its life, a TEC is necessary, according to Takechi.

As the mobile industry shifts from 3G to 4G and 5G, cellular network infrastructure must be able to handle ever-increasing data traffic. To maintain this data traffic over the air, mobile network operators control temperature in their base stations, using TECs. 

Similarly, as data centers use optical receivers to transmit massive data, “you also need TECs,” said Takechi. Kelk estimates the data center market alone that will deploy TECs will increase tenfold from 2015 to 2020. 

Energy harvesting
Another big opportunity for Kelk is the market for thermoelectric generators (TEG). [[ Continue reading on EE Times US.]](https://www.eetimes.com/document.asp?doc_id=1332417&page_number=3)