Rohm’s chip resistors, diodes are smallest yet

July 25, 2014 // By Graham Prophet
With its RASMID Series Rohm claims to have the smallest electronic components in the industry; the ultra-compact lines have superior dimensional accuracy, for high density, high-performance mobile and wearable products.

RASMID (Rohm Advanced Smart Micro Device) is based on proprietary packaging and manufacturing technologies. The new line-up includes ultra-compact chip resistors in 03015 (0.3 × 0.15 mm) size as well as Schottky barrier diodes in 0402 (0.4 × 0.2 mm) size.

For a long time, Rohm says, it has proven impossible to produce chip resistors smaller than the 0402 size (0.4 x 0.2 mm), mostly due to the package dimensional tolerance of up to ±20 µm during the existing process, chip loss, and other factors. Rohm overcame these challenges by using market-proven proprietary technology breaking completely from convention in order to advance component miniaturisation: As a result, remarkable dimensional accuracy (±10 μm) 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 excellent shock properties and bonding reliability have been secured by reducing size and weight.

The 03015-size resistors are the most compact electronic components available at the production level while featuring high accuracy and improved dimensional precision from ±20 µm to ±10 µm. 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 (0.6 mm × 0.3 mm) while mounting area is reduced by 56%. Dimensional precision also improved from ±20 µm to ±10 µm , 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 employed in both cases for