However, miniaturization and extreme stress are pushing the limits of printed circuit boards (PCB) made of epoxy-resin, glass-fiber fabrics (FR4) and polyamides. High temperatures often cause deformation or decomposition of the plastic materials.
Laser structuring of metal coated thin glass
Due to the thermal expansion characteristics of the materials used, there is subsequently a risk of cracks or breakage in the dielectrical layer. This can, for example, lead to pad cratering, i.e. the formation of craters on the surface of the PCB.
For high temperature applications above 250 °C, thin glass could be a suitable substitute for the conventional polymers used as a basis material for the circuit boards, since glass has a high chemical stability and a low thermal expansion coefficient of 7,2 * 10 6 K 1. The field of aerospace technology has interesting applications for these new, thin glass circuit boards.
Together with project partners, the Laser Zentrum Hannover e. V. (LZH) is developing production processes for multilayer circuit boards based on thin glass with 145 µm thicknesses. The trend to miniaturization and higher processing speeds in the PCB industry is a special challenge for manufacturing. In the “Glass PCB Project”, scientists in the Glass Group of the Production and Systems Department are working on developing two different laser processes for processing these special materials:
First, a laser is used to structure the metal layers. According to the PCB layout, a laser is used to make conducting tracks by removing excess metal from a thin glass base. The advantages of laser ablation are especially apparent in the extremely fine structural resolution of the metal, without causing damage to the sensitive material.
Secondly, a laser is used to form holes or vias to connect the different circuit board layers, or the conventional components. The LZH is currently working on finding suitable laser parameters to drill through the materials without causing thermal damage. Also, the vias should be of high quality, and be reproducible at high speeds. Optimal results aim at generating parallel vias through the glass layers. The process time, which is dependent on the material thickness and the circuit board layout, is presently 2 s for drilling a microvia with a 0.2 mm diameter through a 170 µm thick material, with a tendency towards shorter times.
Also, comparative investigations carried out by project partner TU Berlin (main area of research – Technologies for Micropherics) show that new material systems based on thin glass must use the laser for drilling vias, since conventional, mechanical drilling causes unwanted microcracks, and the service life of the drills is 40 times shorter.
Altogether, three scientific institutes and four industrial companies are involved in the joint project. The LZH develops the laser processes for structuring the circuit board layouts and for drilling the vias, and the industrial partners such as Schott AG provide thin glass materials. The circuit board manufacturer Hotoprint GmbH & Co. KG offers both production processes for the thin glass circuit boards and electroplating. KCS Europe GmbH is in charge of coating technologies (sputtering) of the conducting metal layers on the thin glass. Furthermore, CCI Eurolam GmbH is involved as a specialist for materials for circuit board manufacturing. Process handling of the thin glass sheets for multilayer boards is being researched by the Institute of Transport and Automation Technology (ITA) of the University of Hannover.
The project “Glass PCB – Development of a Multilayer Circuit Board Based on Thin Glass” will be funded by the Central Innovation Program SME (ZIM) of the Federal Ministry of Economics and Technology (BMWi) until the middle of 2014.
Lena Bennefeld | Electronic Circuit Board Based o
Dresdner scientists print tomorrow’s world
08.02.2017 | Fraunhofer-Institut für Werkstoff- und Strahltechnik IWS
New technology for mass-production of complex molded composite components
23.01.2017 | Evonik Industries AG
Astronomers from Bonn and Tautenburg in Thuringia (Germany) used the 100-m radio telescope at Effelsberg to observe several galaxy clusters. At the edges of these large accumulations of dark matter, stellar systems (galaxies), hot gas, and charged particles, they found magnetic fields that are exceptionally ordered over distances of many million light years. This makes them the most extended magnetic fields in the universe known so far.
The results will be published on March 22 in the journal „Astronomy & Astrophysics“.
Galaxy clusters are the largest gravitationally bound structures in the universe. With a typical extent of about 10 million light years, i.e. 100 times the...
Researchers at the Goethe University Frankfurt, together with partners from the University of Tübingen in Germany and Queen Mary University as well as Francis Crick Institute from London (UK) have developed a novel technology to decipher the secret ubiquitin code.
Ubiquitin is a small protein that can be linked to other cellular proteins, thereby controlling and modulating their functions. The attachment occurs in many...
In the eternal search for next generation high-efficiency solar cells and LEDs, scientists at Los Alamos National Laboratory and their partners are creating...
Silicon nanosheets are thin, two-dimensional layers with exceptional optoelectronic properties very similar to those of graphene. Albeit, the nanosheets are less stable. Now researchers at the Technical University of Munich (TUM) have, for the first time ever, produced a composite material combining silicon nanosheets and a polymer that is both UV-resistant and easy to process. This brings the scientists a significant step closer to industrial applications like flexible displays and photosensors.
Silicon nanosheets are thin, two-dimensional layers with exceptional optoelectronic properties very similar to those of graphene. Albeit, the nanosheets are...
Enzymes behave differently in a test tube compared with the molecular scrum of a living cell. Chemists from the University of Basel have now been able to simulate these confined natural conditions in artificial vesicles for the first time. As reported in the academic journal Small, the results are offering better insight into the development of nanoreactors and artificial organelles.
Enzymes behave differently in a test tube compared with the molecular scrum of a living cell. Chemists from the University of Basel have now been able to...
20.03.2017 | Event News
14.03.2017 | Event News
07.03.2017 | Event News
24.03.2017 | Materials Sciences
24.03.2017 | Physics and Astronomy
24.03.2017 | Physics and Astronomy