Replication performance of Si-N-DLC-coated Si micro-molds in micro-hot-embossing

Abstract

Micro-hot-embossing is an emerging technology with great potential to form micro-and nano-scale patterns into polymers with high throughput and low cost. Despite its rapid progress, there are still challenges when this technology is employed, as demolding stress is usually very high due to large friction and adhesive forces induced during the process. Surface forces are dominating parameters in micro-and nano-fabrication technologies because of a high surface-to-volume ratio of products. This work attempted to improve the surface properties of Si micro-molds by means of silicon-and nitrogen-doped diamond-like carbon (Si-N-DLC) coatings deposited by dc magnetron cosputtering on the molds. The bonding structure, surface roughness, surface energy, adhesive strength and tribological behavior of the coated samples were characterized with micro Raman spectroscopy, atomic force microscopy (AFM), contact angle measurement, microscratch test and ball-on-disk sliding tribological test, respectively. It was observed that the doping condition had a great effect on the performance of the coatings. The SiN -DLC coating deposited with 5 × 10 −6 m 3 min −1 N 2 had lowest surface roughness and energy of about 1.2 nm and 38.2 × 10 −3 N m −1 , respectively, while the coatings deposited with 20 × 10 −6 and 25 × 10 −6 m 3 min −1 N 2 showed lowest friction coefficients. The uncoated and SiN -DLC-coated Si micro-molds were tested in a micro-hot-embossing process for a comparative study of their replication performance and lifetime. The experimental results showed that the performance of the Si micro-molds was improved by the SiN -DLC coatings, and well-defined micro-features with a height of about 100 μm were fabricated successfully into cyclic olefin copolymer (COC) sheets using the SiN -DLC-coated micro-molds.

Heat Resistant Properties of Some Elements-Incorporated Diamond-Like Carbon Films and Their Trial Applications for Micro End Mill Coatings

“…This silicon oxide layer prevents direct contact between the film and ball when sliding, resulting in the low friction forces. Additionally, in the case of the Si-N-DLC film, the result indicates a low friction coefficient due to the incorporation of silicon and nitrogen [21]. However, the nitrogen content may be less influential than the silicon content, which was described in the literature [22].…”

The study and fabrication of DLC micropattern on roll mold

“…In general, the DLC film spectrum can be fitted into Gaussian peaks at approximately 1550 cm −1 (G peak) and 1355 cm −1 (D peak). 4 The fitting parameters: peak position and relative integrated intensity ratio (ID/IG), are used for characterized the materials. [5][6][7] The Raman spectrums of N-DLC film presents a G peak near 1525 cm −1 to 1565 cm −1 and D peak was measured near 1355 cm −1 to 1360 cm −1 .…”

Development and experimental validation of an analytical model to predict the demoulding force in hot embossing

“…Other studies also showed that mould and polymer materials have an effect on the adhesion phenomena (Guo et al 2007a, Saha et al 2010, Jaszewski et al 1999, Park et al 2004. For instance, the application of coatings on the mould surface can improve the demoulding in HE as it reduces the influence of the chemical and physical interactions.…”