New Cu(GeN_x) film in barrierless metallization for LED heat dissipation

Abstract

In this study, we explore new Cu(Ge) and Cu(GeNx) films for LED heat dissipation. The films are Cu-alloy seed layers, fabricated by co-sputtering Cu and Ge in an Ar or N2 atmosphere on either Ta/Al2O3 or polyimide substrates. The Cu alloy films are then annealed at 600 and 730 °C, respectively, for 1 h without notable Cu oxide formation at the Cu–Ta/Al2O3 interface. No Cu oxide is formed at the Cu–polyimide interface either after annealing the films at 310 °C for 1 h. The film formed atop an Al2O3 substrate contains a trace amount of GeNx and is thermally stable up to 730 °C, and the film formed atop a polyimide substrate is thermally stable up to 310 °C, both exhibiting a low resistivity and a high thermal conductivity. Such a thermal feature makes the Cu(GeNx) film a good candidate material in barrierless metallization for many industrial applications, such as LED heat sinks.

A new Cu(TiBNx) alloy film for boosting the per-watt illuminance of high power LEDs

“…All the films tested throughout this study have been all deposited on a Ta=PI substrate unless otherwise specified. For brevity throughout this text, "the two films" refers to a Cu(TiBN x ) and a Cu(TiB) film, while "the three films" to the two films and a pure Cu film, and "the four films" to the three films and a Cu(GeN x ) 10) film (the order of the individual films may differ within each group in various cases).…”

“…The three films then remained in the chamber and were let to reduce to 50 °C with the cooling process closely recorded. A Cu(GeN x ) film was also tested for the same purpose using the same scheme and with the same equipment by the same operator in another study 10) conducted by the author, and its cooling result is hereby combined with that of the three films for a full comparison. The cooling durations of the four films from 340 to 50 °C are tabulated in Table V.…”

“…One of the methods we have explored to decrease the thermal resistance, and increase the thermal conductance, of an LED substrate has been to deposit a Cu-alloy film, via Cu metallization, on the other sideopposite to the chipof the substrate. After a Cu(GeN x ) film explored by us for a similar goal has been proven valid, 10) we have further explored other alloy films to further improve high power LED illuminanceall without luck until the present study. For a close comparison between the two films, i.e., Cu(TiBN x ) vs Cu(GeN x ), we feel it beneficial to present the results of this study in a format akin to that we have presented in our prior study 10) so that its well-addressed background statements and experimental procedure might not be missed.…”

“…After a Cu(GeN x ) film explored by us for a similar goal has been proven valid, 10) we have further explored other alloy films to further improve high power LED illuminanceall without luck until the present study. For a close comparison between the two films, i.e., Cu(TiBN x ) vs Cu(GeN x ), we feel it beneficial to present the results of this study in a format akin to that we have presented in our prior study 10) so that its well-addressed background statements and experimental procedure might not be missed. That being said, the present study offers a new perspective in LED illuminance and scrutinizes the two films' actual effect on high-power-LED illuminance when they are applied to a flexible Ta=polyimide (Ta=PI) substrate which shall be described later.…”

“…Cu-metallization has been adopted in both our prior 10) and the present studies as the microelectronic component dimension has been continuously downsized to increase transistor or component density. 10) Cu by far has been the most favorable metallization material for interconnects in ultra large scale integrated circuits (ULSICs) owing to its fine electric conductivity. [11][12][13][14] Before using Cu, some issues must be addressed, nevertheless.…”