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Electrical leakage in low-k dielectric/Cu interconnects is a continuing reliability concern for advanced <22 nm technologies. One leakage mechanism deserving increased attention is electron transport across the Cu/dielectric capping layer interface. The Schottky barrier formed at this interface is an important parameter for understanding charge transport across this interface. In this report, we have utilized x-ray photoelectron spectroscopy to investigate the Schottky barrier formed at the interface between polished Cu substrates and standard low-k a-SiC(N):H dielectric capping layers deposited by Plasma Enhanced Chemical Vapor Deposition. The authors find the Schottky Barrier at this interface to range from 1.45 to 2.15 eV depending on a-SiC(N):H composition and to be largely independent of various in situ plasma pretreatments.

In order to understand the fundamental mechanisms involved in electrical leakage in low-k/Cu interconnects, we have utilized x-ray photoelectron spectroscopy to determine the Schottky barrier present at interfaces formed by plasma enhanced chemical vapor deposition of low-k a-SiOxCy:H thin films on polished Cu substrates. We find the Schottky Barrier at this interface to range widely from 1 to >4 eV and to be dependent on the amount of network carbon incorporated into the a-SiOC:H thin films.

Due to a low dielectric constant (k = 4-4.5) and high density (1.8-2.0 g/cm 3 ), Plasma Enhanced Chemically Vapor Deposited (PECVD) boron nitride (BN) is an intriguing Cu diffusion barrier material for use in low-k/Cu interconnects. However, relatively little is known about the electrical leakage behavior of BN in Cu interconnects or the Schottky barrier formed at the interface between these two materials. In this regard, x-ray photoelectron spectroscopy (XPS) has been utilized to determine the Schottky barrier present at the interface between polished Cu substrates and PECVD BN. Our measurements indicate a substantial barrier of 3.25 ± 0.25 eV for this interface.

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