In the relentless pursuit of enhancing semiconductor performance and reliability, researchers have long grappled with the challenge of ensuring strong adhesion between copper (Cu) and dielectric layers. This interfacial strength is crucial for the longevity and efficiency of semiconductor devices, particularly in the energy sector where reliability is paramount. A recent study published in Applied Surface Science Advances, led by Young-Min Ju from the Department of Mechanical Engineering at Hanyang University in Seoul, South Korea, sheds new light on this critical issue.
Ju and his team employed a sophisticated technique known as the laser spallation test to measure the interfacial adhesion strength between copper and various dielectric films. The method involves generating a compressive stress wave using a laser pulse and analyzing the interface stress through wave propagation simulation. This approach allowed the researchers to quantify the adhesion strength with unprecedented precision.
The findings revealed that plasma-enhanced chemical vapor deposition (PECVD) silicon oxide exhibited the highest adhesion strength, measuring 63.57±11.31 MPa. This was followed by PECVD silicon nitride at 53.95±12.04 MPa and low-pressure chemical vapor deposition (LPCVD) silicon nitride at 26.06±6.44 MPa. “The results indicate that the type of dielectric film and its deposition method significantly influence the interfacial adhesion strength,” Ju explained.
To understand the underlying mechanisms, the researchers conducted a series of analyses. Scanning electron microscopy with energy dispersive spectroscopy (SEM-EDS) confirmed that failure consistently occurred at the Cu/dielectric interface. Atomic force microscopy (AFM) revealed that the rougher surface of PECVD silicon oxide enhanced mechanical interlocking, contributing to its superior adhesion. Additionally, X-ray photoelectron spectroscopy (XPS) and Fourier transform infrared (FTIR) analyses identified the presence of hydroxyl groups (-OH) at the interface, which facilitate Cu oxidation and the formation of Cu-O bonds.
The implications of this research are far-reaching, particularly for the energy sector. As the demand for more efficient and reliable semiconductor devices continues to grow, understanding and improving Cu/dielectric interfacial reliability becomes increasingly important. “This comprehensive study provides critical insights that can guide the development of more robust semiconductor devices,” Ju noted. “By optimizing the deposition methods and materials, we can enhance the performance and longevity of these devices, which is essential for applications in renewable energy and advanced electronics.”
The study’s findings suggest that future developments in semiconductor technology may focus on leveraging the unique properties of PECVD silicon oxide and other high-adhesion dielectric films. This could lead to the creation of more durable and efficient multi-level metallization structures, reducing the risk of delamination and improving overall device reliability.
As the energy sector continues to evolve, the need for reliable and efficient semiconductor devices will only intensify. The research conducted by Young-Min Ju and his team at Hanyang University represents a significant step forward in addressing this challenge. By providing a deeper understanding of Cu/dielectric interfacial adhesion, this work paves the way for innovative solutions that can drive progress in the energy sector and beyond. The study was published in Applied Surface Science Advances, which translates to “Applied Surface Science Progress.”