Wireless sensors are fabricated on flexible plastic films by means of screen printing and via-hole filling. The wireless sensors are battery free with data and power transmission functions. The sensors, fabricated on polyethylene terephtalate films, are designed based on RFID technology. Using an additive patterning process known as screen printing, metallization on polymer films is created. Both sides of a polymer film are printed with metallic patterns and connected with micro vias filled with conductive paste. One side of the film consists of printed electrical traces for discrete components like resistors and transistors that would be mounted onto it; the other side consists of a printed inductive coil used for wireless data and power transmission. The micro vias, which have a diameter of 120 lm, are formed by mechanical punching and filled with conductive silver paste. The size of one sensor unit is approximately 2 cm 9 1.5 cm; an array of 4 9 7 sensor units are printed over an area of 15 cm 9 15 cm on a PET film. Details of manufacturing processes, component assembly and functionality test are presented in this paper.

Low-temperature co-fired ceramic (LTCC) offers many advantages as a material of multi-functional substrates for high-density, high-frequency microelectronic applications, as well as for enabling microsystems. One of the key challenges in manufacturing multilayered ceramic substrates is fabricating micro patterns on unfired green ceramic sheets, and micro embossing is an alternative and promising method for this purpose. This paper presents our achievements in fabricating micro patterns over a large area on multilayered green ceramic substrates using micro roller embossing. A commercialized roller laminating machine was modified and used as the roller embossing apparatus. The feasibility of micro roller embossing on green ceramic substrates with an effective panel size of 150 mm × 150 mm has been successfully demonstrated. Micro patterns, including channels and electrical passives with 50 µm line-width, were formed over the whole panel area. The influence of main process parameters on the pattern quality of roller embossing has been investigated and confirmed.

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This paper presents a micro roller embossing process for patterning large-area substrates of laminated green ceramic tapes. The aim of this research is to develop a large-area microstructure formation technique for green ceramic substrates using a thermal roller laminator, which is compatible with screen printing apparatus. A thin film nickel mold was developed via photolithographic patterning and nickel electroplating on a 75-lm-thick nickel film. The mold had an effective panel size of 150 mm 9 150 mm with the height of plated protrusive patterns being about 38 lm. Formation of micro patterns was successfully demonstrated over the whole panel area on laminated green ceramic tapes using roller embossing. Micro patterns for inductors, heaters as well as interconnection with 50 lm line-width were embossed on green ceramic substrates. By means of tuning process parameters including roller temperature, applied pressure and feeding speed, we have demonstrated that micro roller embossing is a promising method for patterning large-area green ceramic substrates.

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