Nuvoton releases 379 nm, 1W UV laser diode
Japanese firm Nuvoton Technology has started mass production of its high-power UV semiconductor laser (379 nm, 1.0 W), which delivers industry-leading optical output in a 9.0 mm diameter CAN package (TO-9).
The product is said to achieve short wavelength, high output power, and long lifetime (three elements previously considered difficult for UV semiconductor lasers) through a proprietary device structure and advanced high-heat-dissipation packaging technology.
As a result, it contributes to fine patterning and improved production throughput in maskless lithography for advanced multi-chip semiconductor packaging.
The mainstream method for forming wiring connections between multiple chips has been exposure technology using the i-line (365 nm) of the mercury spectrum and photomasks. But there's growing interest in maskless lithography technology, which directly draws wiring patterns based on design data without using photomasks.
As one of the key light sources in maskless lithography, semiconductor lasers have faced increasing demands for shorter wavelengths closer to the i-line (365 nm) and higher output, in order to enable finer wiring and improve equipment throughput.
The challenge is that UV semiconductor lasers generally suffer from significant heat generation caused by low wall-plug efficiency (WPE), and a tendency for device degradation caused by UV light, making stable operation at high output levels above 1.0 W difficult to achieve.
To meet these requirements, Nuvoton has take a dual approach by focusing on both a “device structure that enhances wall-plug efficiency (WPE)” and a “high thermal conduction package technology that effectively dissipates heat,” enabling it to develop a product that successfully combines short wavelength, high output, and long lifetime.
In addition to optimising the emission layer and optical guide layer, Nuvoton has adopted a proprietary structure that precisely controls the doping profile. By reducing light absorption loss and operating voltage, this allows electrical energy to be converted into light more efficiently.
For improved heat dissipation, the diodes use a submount made of high thermal conductivity materials and in addition, the package materials have been revised to reduce thermal resistance. As a result, rises in device temperature are suppressed, allowing for stable operation at high output.
This product has been added to the company's lineup of 'semiconductor laser-based alternatives to mercury lamps'.
