Innovation Insights - Technical White Papers

Cicor white papers provide additional, in-depth technical information on technologies and services. Furthermore you will find details of manufacturing processes, areas of application and solutions, competent explanations and information about scientific backgrounds.

Thin Film Based LCP Multi-Layer Circuits: Manufacturing Technology and Characterization


In contrary to multi-layer circuits traditionally manufactured in standard PCB (Printed Circuit Board) technology, this article specifically describes a technology which combines the benefits of Thin Film Technology processes with methods from the PCB technology. Noble metals for the formation of conductor lines combined with laminated LCP (Liquid Crystal Polymer) polymers as substrate and insulator materials allow the formation of multi-layer circuits with only a very limited number of different participating materials. Such types of circuits can be made completely out of biocompatible materials and thus, are excellently suitable for applications inside the human body.

This article will describe the general aspects of this technology and discuss the process flow for the manufacturing of thin film based LCP multi-layer circuits. Characterization results from stability examinations of these circuits in buffered saline solution are shown and discussed to prove the performance of the manufactured circuit structures.

How to avoid the 8 most common outsourcing mistakes


The medical devices industry has become very competitive. The ongoing trend for global outsourcing of medical devices is based on many market drivers and challenges: price competitions, the need to reduce costs, growing complexity in product design and engineering, strict approval norms, the need for specialized manufacturing skills and lacking in-house production infrastructures and capabilities are the main drivers. Contract manufacturing partners can help accelerate time to market for new products, thus speeding up return on investment.

Particularly for low-volume devices, manufacturers may find it cost-prohibitive to hire experts and to purchase the technologies that are required. Because many manufacturing partners already have facilities, staff, equipment, and supply chains in place, they can begin design, optimization, testing, or manufacturing quickly. When targeting international markets, contract manufacturing partners can provide an established, local presence in key regions, including already built and scalable manufacturing infrastructure and a network of established suppliers.



Box Building - Comprehensive solutions from the EMS partner


The present white paper shows the services of a comprehensive solution provider from the idea to the ready-for-dispatch product.



Advanced Thin-Film Substrates in Cu-AlN Technology


For applications dealing with high power, like laser diodes or RF amplifiers, thermal management is a crucial topic. Thus, for packaging of these devices, high thermal conductivity materials are essential. AlN, compared to diamond or SiC, hereby has the advantage of matching closely the thermal expansion coefficients of Si or GaAs, additionally reduced substrate costs are an important issue. The second task is to provide metallization with high thermal and electrical conductivity for interconnection of devices and coupling of devices, substrate and periphery. For this, copper should be the material of choice. Our outstanding technology, e.g. already used for laser sub mounts, combines the benefits of AlN substrates and Cu metallization by providing low resistivity interconnects and high thermal conductivity substrate material.

Our paper presents recent technological approaches on the new technology as well as application examples using the Cu filled vias.

Flexible Thin-Film Multilayer Substrates


Ongoing development in electrical systems and circuits lead to increasing complexity and also increasing requirements in today’s thin-film substrates. Settled traditionally in between the semiconductor circuits and the standard PCB applications, thin-film substrates often provide an essential link between these two worlds.

Recent developments in Cicor’s thin-film processes allowed for the production of multi-layer substrates for various applications. Besides standard rigid thin-film substrates, carrying the metal and insulator stacks, also flexible multilayer applications are possible.

The nature of flexibility leads to the exquisite suitability for medical and biological applications, whereby the individual properties have to be adjusted to fit the specific application requirements. A major advantage in contrary to the PCB-based flexible multilayer substrates are the higher achievable resolution (smaller lines and spaces), as well as a wider spectrum of usable materials. Also the possibility of simple handling during surgery and biocompatibility, when used for medical implants, are some of the key requirements on such parts.

Different kind of products and prototyping was carried out by Reinhardt Microtech in the field of flexible multilayer substrates for medical use. Some applications hereby lie in the field of retinal implants which can be used for, at least partially, regaining sight for blind people. An example of such a sys-tem is combined of a low-power CMOS vision IC, which is operating with DC free supply, flexible multi-layer carrier substrate, and additional peripheral equipment.

Additional opportunities are in the field of measuring devices, used e.g. for online measurements during surgery, which are tracking important parameters of the human body.

This publication will show general aspects of the fabrication of multilayer substrates and the possibilities which lie in the use of these. Additional focus will be the application of thin-film based systems in the field of medical/life sciences applications.

Improved Thermal Management in High Power Applications by utilizing novel „Filled Via“ Thin-Film Substrate Technology


Airborne and space borne SAR instruments with active array antennas will become more and more important in near future. One of the key elements in this kind of antennas is the hundreds or thousands of T/R Modules which are connected to discrete radiators arranged in array configurations. These T/R-Modules, each requiring separate electrical connections and amplifier circuits, are the cost-driver of the overall system. For such modules, as a representative of high performance systems, the use of advanced substrate technologies can improve the system properties and enhance the overall performance.

Especially in applications dealing with high power amplifiers or laser diodes, the thermal management is a crucial topic. Whereas, conventional RF substrate technologies use only partly metallized via for through-substrate interconnects, our new technology provides solid Cu filled via interconnects. These, together with high thermal conductivity substrate materials, like e.g. AlN, improve the thermal properties of the whole assembly. Naturally, also the electrical resistance is reduced and power loss minimized. Also according to manufacturing issues, some drawbacks of only partly metallized throughholes can be avoided.

This paper describes the properties of the Cu filled via technology together with the fabrication flow for RF and high power application substrates. The main focus is laid on simulation results for the thermal management capabilities of different, i.e. AlN and Al2O3 substrate material incorporating Cu filled via.

Solid Filled Via


In ceramic systems, like RF circuits or even more complex micro systems or MEMS, generally electrical interconnects play an important role. They might be used for transmitting switching currents for relays, high frequency RF signals or digital signals as well. In hermetically packaged circuits or systems, also reliable connections to the “outer” world are required. Thus, the properties of such interconnects (especially via through the substrate) are important for the performance of the overall system.

Our technology, incorporating solid Cu filled via, provides several advantages over conventional plated through-holes in thin film technology, as well as compared to e.g. LTCC or similar. Some of the advantages are the lower electrical resistivity and higher current transport capabilities due to the increased cross section. The use of Cu additionally improves the thermal heat dissipation in systems with low thermal conductivity substrate materials. Applications with high power devices or high current switching can be realized by providing the ability of efficient coupling to heat sinks.

Sophisticated circuits can be implemented by using the filled via substrates, as fine line patterning can be done directly besides via interconnects, while substrate topology is kept really flat. Thus, precise integrated couplers, filters or similar are standard components of such circuits, as fine line width patterning is possible down to about 10 μm.

Our paper will provide an overview of the fabrication technology of Solid Filled Via substrates. A comparison between different interconnect technologies is also shown.

Technology for Medical Human Implants


Increasing complexity of today’s electrical circuits’ lead to a growing demand for thin film “interface” substrates. Such substrates provide an important link between integrated electronics and peripheral accessories like amplifiers or signal processing units. Possible applications lie in the field of laser sub mounts with electrical connections for re-routing or even more sophisticated in the field of medical applications or implants. Whereas conventional thin film multilayer are mostly realized on stiff ceramic substrates (aluminum oxide, aluminum nitride), the extraordinary challenge with medical applications often comes from the required flexibility of the circuit. Biocompatibility and practical handling of the assembly play an important role in these applications.

This publication will show general aspects of the fabrication of thin film multilayer, stiff as well as flexible, and show the main differences which may appear, and be requested, in such systems.

A special focus shall be laid on an application for a retinal implant. In this application a vision chip, developed by the University of Ulm, is combined with a flexible thin film multilayer forming a human medical implant for regaining, at least partly, the eyesight for blind people. The special issues of the implantable chip are the low supply voltage and DC free external supply of the circuit.

The vision unit itself consists of a 40 x 40 pixels array with light sensors and electrode drivers, which are addressed sequentially to improve power consumption and spatial resolution of perception. This guarantees for a long-time operation and minimization of chemical reactions on the periphery.

Thin - Film Flexible Circuits Improved Interconnects for DC and RF Thin - Film Applications


This paper will highlight general aspects of the fabrication of thin film flexible circuits, realized using different substrate materials. Fundamental properties and results from reliability measurements will be presented and discussed, also in view of practical use in different applications.

DenciTec - Ultra High Density Interconnect Printed Circuit Boards


PCB manufacturers have been using different technologies for the production of printed circuits. Historically, the two methods panel plating and pattern plating have been used for many decades. Both of the methods have their pro’s and con’s and their clear limitations. For circuits with line widths and spacings of less than 35 microns, several concessions have to be made to achieve acceptable results and output. The currently used production process is typically not enabling the use of the whole set of possibilities of modern PCB technology, e.g. for example via stacking, via in pad structures or integrated antenna.

The path to innovative Solutions - active implants


To help people to be treated for the widespread disease lower case glaucoma (increased eye pressure, which when left untreated can lead to loss of vision), the company Implandata Ophthalmic Products has, over recent years, developed a system which enables measurement of eye pressure at arbitrary points in time 24 hours a day. This allows better treatment with the right dosage of medication. During this time period Cicor served and still serves as a Partner in development and industrialization of the sensor and the associated electronic devices. This paper describes the single elements of the system with the respective requirements, and details which solutions Cicor has established.

Protective coatings for electronic printed circuit board assemblies


Humidity, dust, extreme temperatures and changing environmental conditions can place considerable strains on electronic printed circuit board assemblies (PCBAs). Sooner or later, electronics used in such environments or under such conditions are likely to suffer failures. This risk can, however, be mitigated through the application of appropriate protective coatings.

This Cicor white paper provides guidance for both the automated and manual coating of electronic PCBAs. Observing the points outlined in this white paper will decidedly improve the safety aspect of the coating process.

If the design of an electronic PCBA is completed without factoring in any potential protective coating, subsequent coating may no longer be possible or would require significant additional effort and cost. For this reason, the potential application of a protective coating to electronic components should already be taken into consideration during the design phase. Such early design-related decisions have a fundamental impact on any product's process capability, quality and costs.

Femtosecond Laser in Micro Production


Generation of circuit outlines as well as producing openings in the substrate material to generate electrically conductive connections (e.g. through-holes) or mechanical windows are essential features of thin-film circuitry. As other demands on thin film circuits, like e.g. compatibility with various assembly methods and reliability have risen during the last years, also the requirements on the quality of the mechanical machining of the ceramic or flexible substrate materials have increased. Fabrication of vertical side wall interconnects to reduce the required surface area as well as tighter tolerances on outline features are driving the technical improvements.
This paper describes the application of a state-of-the-art laser machine equipped with a femtosecond laser source as high-precision tool for micro machining of flexible and ceramic substrate materials for thin film circuit manufacturing. The advantages of using last generation ultrashort pulse lasers are discussed and compared with a common laser process using a conventional CO2-laser source.