Batteries and Portable Power

ROHM Unveils Smart Micro Devices for Wearables

ROHM Semiconductor unveiled its new RASMID (ROHM Advanced Smart Micro Device) families based on innovative proprietary processes. The company has been a pioneer in miniaturization technology, and is continually cultivating new methods to achieve the smallest devices in the industry. Among others, the new line-up includes ultra-compact chip resistors in 03015 (0.3 x 0.15mm) size as well as Schottky barrier diodes in 0402 (0.4 x 0.2mm) size.

In recent years, the functionality of portable and mobile equipment such as smartphones, tablet PCs, health and fitness devices, evolved dramatically and the market saw an increasing need for thinner, more compact component form factors while also requiring greater precision and reliability. For a long time, it has proven impossible to produce chip resistors smaller than the 0402 size (0.4×0.2mm), mostly due to the huge package dimensional tolerance of up to ±20um during the existing process, chip loss, and other factors.

ROHM overcame these challenges by utilizing market-proven proprietary technology breaking completely from convention in order to advance component miniaturization: As a result, remarkable dimensional accuracy (±10μm) has been achieved, which also reduces lateral electrode irregularities. Enhanced dicing methods enable minimal adhesion areas and increased mounting accuracy. Mounting errors and "tombstoning" are significantly reduced by adopting bottom electrodes. High-precision high-density mounting has become reality through joint development of mounting technology with ROHM's partners and finally, excellent shock properties and bonding reliability have been secured by reducing size and weight.

In consequence, ROHM's 03015-size resistors are the most compact electronic components available at the production level while featuring high accuracy and improved dimensional precision from ±20um to ±10um. The device size is reduced by 56% over conventional 0402-size products and the required mounting area is reduced by 44%.

The world's smallest class of 0402-sized Schottky barrier diodes enable high-density mounting ideal for mobile devices. Size is reduced by 44 % compared to the conventional 0603 size (0.6mm - 0.3mm) while mounting area is reduced by 56%. Dimensional precision also improved from ±20um to ±10um, enhancing stability in existing automated mounting equipment. By adopting proprietary chip device structures and ultra-precise processing techniques, key electrical characteristics such as forward voltage (VF) and high power (0.1W) are maintained while reducing size and thickness compared to conventional 0603-size products. Gold electrodes are utilized in both cases for superior solderability and reliability.

ROHM Semiconductor
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