Printing of Patterned Copper on Pliable, Microtextured PDMS/Ceramic Composites

Abstract

In this work, we present a novel printing technique that enables the usage of PDMS and ceramic powder mixed PDMS composites (we refer as “PDMS-ceramic composites” in this context), as a substrate for printing of copper conduction layers. This technique is based on microtransfer molding (μTM) and lift-off for pattern formation [4]. Another key feature is the usage of microtextured PDMS and PDMS-ceramic composites before any copper film deposition. Our microtextured surface is composed of pyramid shaped wells (100 μm depth and 150 μm sides on PDMS surface). The poor adhesion between PDMS and copper is overcome by oxygen plasma application and titanium deposition before copper layer.In order to demonstrate the convenience of this technique in RF applications, copper conduction lines (5 mm wide, different lengths) were printed on microtextured PDMS substrates. These transmission lines successfully maintained a low resistance during large strain. The printed lines have the DC resistance of 0.5 Ω and conductivity of 1.3e6 S/m, and the transmission analysis of these lines show good results especially in the MHz range when compared to copper tape measurements.Apart from the conduction lines, the substrates can have ranging dielectric constants from 3 (no powder) to 23 (50% D270 powder, provided by TransTech) by volume mixing rule. Dielectric constant is important for RF applications, especially antenna designs. Therefore, provided with a range of dielectric constants, these composite substrates are a great promise in RF field for pliable antenna fabrication [5]. For experiment purposes, some of the transmission lines are printed on these composite substrates as well as pure PDMS.In this study, apart from the fabrication of transmission lines, this novel technique will be applied in a GPS antenna design for demonstration purposes. This antenna design is a single-fed circularly-polarized stacked antenna for tri-band GPS (L1, L2 and L5) applications [6]. For the fabrication of the antenna, polymer-ceramic materials of ε1=16 and ε2=30 will be utilized as the substrates [6].

Rapid selective metal patterning on polydimethylsiloxane (PDMS) fabricated by capillarity-assisted laser direct write

“…Polydimethylsiloxane (PDMS) has been widely used in biooptical-electrical microfluidic systems owing to its excellent chemical compatibility, optical properties and fabrication flexibility [1][2][3][4][5][6]. Microscale structures/patterns can be constructed with PDMS by using a simple mold-casting method.…”

Radio frequency response of flexible microstrip patch antennas under compressive and bending loads using multiphysics modeling approach

“…All above requirements need an effective bonding between the elastomer and the metal at the interface. There are several methods that can be used to print copper directly on to PDMS such as microtexturing, oxygen plasma treatment, and titanium adhesion layer . Oxygen plasma treatment increase the copper adhesion whereas the titanium improves the oxide bond of the metal at the interface by increasing the adhesive strength as reported in .…”

“…There are several methods that can be used to print copper directly on to PDMS such as microtexturing, oxygen plasma treatment, and titanium adhesion layer . Oxygen plasma treatment increase the copper adhesion whereas the titanium improves the oxide bond of the metal at the interface by increasing the adhesive strength as reported in . The titanium oxide film does not change the dielectric properties of PDMS because the adhesion layer is very thin .…”

Biomimicking Topographic Elastomeric Petals (E‐Petals) for Omnidirectional Stretchable and Printable Electronics

“…[ 36 ] www.MaterialsViews.com www.advancedscience.com pyramid tips on PDMS/ceramic composites using microtextured nylon molds but microcracks on the Cu thin fi lm were found just after evaporation of Cu. [ 48 ] Park et al obtained periodic 1D and 2D wavy metal structures on PDMS stamp replicated from pattern-etched Si molds, but they could only be stretched uniaxially or biaxially when the tensile strain was less than 20%. [ 49 ] Compared with these literature reports, the ELD-Cu/E-petal shows obvious advantages in the stretchability range, the omnidirectional stretching capability, and the ease in fabrication.…”

“…Lambricht et al fabricated irregular rough Au/PDMS with rough glass side molds, but its resistance change was more than 100 folds . Apaydin et al obtained Cu thin film with pyramid tips on PDMS/ceramic composites using microtextured nylon molds but microcracks on the Cu thin film were found just after evaporation of Cu . Park et al obtained periodic 1D and 2D wavy metal structures on PDMS stamp replicated from pattern‐etched Si molds, but they could only be stretched uniaxially or biaxially when the tensile strain was less than 20% .…”