Description
Industrially, mechatronic integrated devices (MIDs) are currently manufactured primarily on thermoplastic substrates. For established applications such as smartphone antennas, sensors for industrial equipment and automotive applications, and for positioning switches, this approach offers an ideal solution. However, spatial circuit carriers made of plastic are often no longer able to meet the increased requirements: For example, new mobile communication standards for base antennas demand better high-frequency properties and higher reliability even under harsh conditions, miniaturized sensors in the Internet of Things (IoT) esp. for high temperatures and pressures can only be implemented via spatial shaping, high-power LEDs on 3D-shaped lamps and RADAR sensors for autonomous driving can be designed more powerful, efficient and smaller on the basis of ceramic 3D substrates.
Ceramic-based spatial circuit substrates have the necessary properties to meet these challenges. However, limitations still exist for the fabrication of these ceramic MIDs, which hinder broad industrial implementation for technological or economic reasons: Poorly controllable and expensive laser sources with wavelengths of 248 μm or 308 μm were initially used [1, 2]. Further studies use special sintering conditions and picosecond pulsed lasers [3]. In this case, the sintering process is carried out in a hydrogen atmosphere, which represents a significant additional effort compared to the industry standard. Another approach involves modifying the ceramic starting material and adding copper oxide to it to improve the absorption of laser radiation at 1,064 nm [4] [5]. However, this means that the material qualification has to be completely redone and the properties of the ceramic are changed.
Therefore, the aim of this project is to fabricate three-dimensional ceramic MID by cleverly adapting the LDS process (Laser Direct Structuring or Laser Structuring). This is made possible by a surface pretreatment of the ceramic substrates, which can be removed completely after laser structuring and thus has no effect on the finished product. For this purpose, the base body is coated with a paint that absorbs more than 95% of the laser radiation at 1,064 nm (compared to about 3% for the untreated ceramic). The base body can then be patterned with low laser powers of about 9 W. The color can then be applied to the base body in the already treated ceramic. Finally, the color can be completely removed in the ultrasonic bath, which is necessary anyway. Preliminary investigations have shown excellent results, which are now to be verified, further developed and prepared for use in SMEs in the project. In addition, the process will be compared with the above-mentioned methods and subjected to reliability tests.
Figure 1: LPKF’s lasers are already completely designed and prepared for the structuring of 3D MID; Source: LPKF
Research Objective
The aim of the research project is to establish an industrial 3D-capable process for the pretreatment, structuring and metallization of technically relevant, commercial ceramics (e.g. aluminum oxide, aluminum nitride, zirconium oxide) and to validate the reliability of products manufactured in this way. As proof, example applications of the project-accompanying committee (PA) are to be implemented at the end of the project.
Through comprehensive laser parameter studies with an LPKF Fusion IR laser (FAPS) and a picosecond pulsed green laser from EdgeWave (Hahn-Schickard), various pre-treatments (e.g. acrylic spray, chalk spray, dip coating) on technical aluminum oxide will be investigated. These are evaluated by determining the metallization layer thickness, surface roughness and adhesion strength of the metallization. Through these results, the pretreatment methods are narrowed down and reliability tests (thermal shock tests, moist-heat-aging, high temperature aging) and adaptation to other ceramic substrates is analyzed. Subsequently, an exact compensation of the dimensional deviation between the patterning and the metallization is also calculated. In preparation for three-dimensional applications, the 3D capability of the coating is worked out and verified by a three-dimensional demonstrator.
Figure 2: LDS process incl. pretreatment; Source: Hahn-Schickard, Lehrstuhl FAPS (FAU)
Benefits and Economic Significance for SMEs
Suppliers and users specializing in electronic assemblies with special requirements (see PA) will be able to significantly strengthen their business fields and position themselves competitively in the international electronics market by means of the planned, cost-effective manufacturing process for 3D ceramic MID. Manufacturers of LDS technology (Laser Direct Structuring or Laser Structuring) on thermoplastics will be enabled by the project results to offer their services on ceramic substrates as well. This will expand their areas of application. The comprehensive parameter studies enable the companies to already significantly narrow down the parameter window for future applications. In addition, the companies benefit from the calculated compensation of the dimensional accuracy, so that an exact layout with tightly defined dimensions is possible in just a few iterations. Examples of applications include basic antennas for mobile communications, but also high-temperature sensor technology or implant applications.
Research Institutes
For further contact details, please contact the office. E-Mail to office
University Erlangen-Nürnberg
Chair FAPS
Hahn-Schickard-Gesellschaft für angewandte Forschung e.V.
Institute for Microstructure Technology
Project Accompanying Companies
The Research Association 3-D MID is still looking for companies to accompany the project. If you are interested, please contact the office via phone (+49 911 5302-9100) or E-Mail (info@3d-mid.de). E-Mail to office
Sources
[1] SHAFEEV, G.A. Laser activation and metallisation of oxide ceramics [online]. Advanced Materials for Optics and Electronics, 1993, 2(4), S. 183-189. ISSN 1057-9257. Verfügbar unter: doi:10.1002/amo.860020405
[2] DESILVA, M.J., A.J. PEDRAZA und D.H. LOWNDES. Electroless copper films deposited onto laser-activated aluminum nitride and alumina [online]. Journal of Materials Research, 1994, 9(4), S. 1019-1027. ISSN 0884-2914. Verfügbar unter: doi:10.1557/JMR.1994.1019
[3] ERMANTRAUT, E., H. MULLER, W. EBERHARDT, P. NINZ, F. KERN, R. GADOW und A. ZIMMERMANN. New Process for Selective Additive Metallization of Alumina Ceramic Substrates [online]. IEEE Transactions on Components, Packaging and Manufacturing Technology, 2019, 9(1), S. 138-145. ISSN 2156-3950. Verfügbar unter: doi:10.1109/TCPMT.2018.2881410
[4] NINZ, P., F. KERN, S. PETILLON, W. EBERHARDT, A. ZIMMERMANN und R. GADOW. Selective laser induced autocatalytic metallization of NiO and Cr2O3 doped alumina zirconia ceramic substrates [online]. Journal of the European Ceramic Society, 2020, 40(11), S. 3733-3743. ISSN 09552219. Verfügbar unter: doi:10.1016/j.jeurceramsoc.2020.01.026
[5] BACHY, B., R. SÜß-WOLF, L. WANG, Z. FU, N. TRAVITZKY, P. GREIL und J. FRANKE. Novel Ceramic-Based Material for the Applications of Molded Interconnect Devices (3D-MID) Based on Laser Direct Structuring [online]. Advanced Engineering Materials, 2018, 20(7), S. 1700824. ISSN 14381656. Verfügbar unter: doi:10.1002/adem.201700824
