Markus Hanika

Split sputter mode: a novel sputtering method for flat-panel display manufacturing

Advanced static DC magnetron sputtering methods based on the magnet wobbling technique were investigated to achieve highly uniform and homogeneous metallization layers. The novel split sputter mode (SSM) method, wherein the deposition process is divided into two distinct steps, enables the AKT rotary cathode technology to provide excellent layer properties, while keeping a high production throughput. The effectiveness of the SSM technique was demonstrated through copper-coated large-area substrates.

Sputtered Ti-Cu as a superior barrier and seed layer for panel-based high-density RDL wiring structures

This paper demonstrates that sputtered Ti-Cu is a superior barrier and seed layer on glass and organic panel substrates, over traditional electroless seeding, for the fabrication of ultra-fine copper traces (2-5μm) on dry film polymer dielectrics for high-density 2.5D interposers. The current semi-additive processes using electroless Cu seed face several challenges in scaling the copper trace widths below 5μm due to two main reasons: high-roughness of dielectric and high-thickness of copper seed. In this paper, both the above limitations are addressed by an advanced Physical Vapor Deposition (PVD) process that can be scaled to large panels with high throughputs. The PVD process developed in this study is capable of depositing Ti-Cu barrier and seed layer on 500 mm size panels at a low enough temperature for dry film polymer dielectrics of glass transition temperatures (Tg) of 150-160°C. The superiority of sputtered Ti-Cu over the conventional electroless Cu seeding for achieving good and reliable adhesion between Cu and dry film polymer dielectrics was investigated by peel strength measurements after highly-accelerated stress tests (HAST). The results indicate that sputtered process results in higher peel strengths and without adhesive failures at the Ti-Cu-polymer interfaces. Adhesive failures, however, were observed with the traditional electroless seed processes. In addition, the PVD processes resulted in small 2-5μm Cu traces on smooth dielectric films like ZS-100, requiring no desmear treatment. Such a process promises to be scalable to large panels leading to low-cost fabrication of high-density 2.5D interposers.

Layer-thickness simulation for static thin-film deposition on Gen 6/Gen 7 substrates

— The movement of particles from a target to a substrate during the sputter process was studied using the Monte Carlo Simulation technique. The momentum and energy distribution of the ejected particles were taken into account along with the change of momentum and energy in their collisions with gas atoms. The momentum transfer from the ejected target atom to the gas atom was used to estimate the gas rarefaction in front of the target. Layer-thickness distributions of different target materials were calculated and compared with experimental measurements. The results were used to optimize the uniformity of static thin-film depositions on Gen 6/Gen 7 substrates from a large-area cathode array.

6.2: Layer-Thickness Simulation for Static Thin-Film Deposition on Gen6/Gen7 Substrates

Monte Carlo simulations were performed to examine the layer thickness distribution of a sputter deposition process. The numerical results were used to optimize the uniformity of a large area cathode array for static thin film deposition on Gen6/Gen7 substrates. The influence of different target materials was investigated.