Picture shows a SLIM.flex PCB

SLIM.flex PCBs

Smallest Design, Biggest Advantages

SLIM.flex – Technology That Inspires

Small, compact, maximally bendable and highly resilient: These are the requirements for modern printed circuit boards. Whether for research or the medical, vision technology or automotive industries, SLIM.flex meets them with flying colors - even with the smallest housing volumes.

Wherever small and ultra-small sensors are required, the ultra-thin SLIM.flex products are convincing thanks to available standards as well as enormous robustness combined with maximum flexibility. Keyword flexible: This also applies to availability. From individual samples to series production, all variants can be ordered from the experts at Würth Elektronik.

Our Know-how – Your Profit!

Advantages of Smart Würth Elektronik SLIM.flex Technology

  • Extremely thin: Fits even the smallest housings thanks to reduction of thickness by up to 70 percent
  • Anylayer via: Each layer can be connected to each other via laser drilled microvias
  • Dielectric strength: Safe dielectric strength of 500 volts – suitable for higher voltages
  • Highest reliability: Very robust in the soldering process (even with multiple lead-free soldering) and optimally suited for harsh-environment applications
  • High-tech cable harness: Ultra dense, impedance defined or shielded signals in a very small space – 100 percent more signals possible in half the installation space

SLIM.flex in the Particle Accelerator at CERN, Switzerland

Application Example

Intensive, verified quality tests have shown that SLIM.flex can withstand even the highest temperature stress and thus qualifies for use in highly demanding environments. It is not without reason that SLIM.flex is installed in detectors of the world's largest particle accelerator, among others.

SLIM.flex will be installed in the detectors of the new CERN particle accelerator.

Detector in the Lhc Particle Accelerator Cern

SLIM.flex as a High-tech Cable Harness

Application Example

SLIM.flex technology allows ultra-dense, impedance-defined or shielded signals in the smallest possible space. Compared to conventional harnesses, this allows up to 100 percent more signals in half the installation space. Since there are no restrictions on signal routing and geometry in the design of the SLIM.flex harness, the harness can be designed in a very variable way.

Thanks to the universal layer structure, the number of flex layers can be changed as needed during layout without changing the stackup - and at no extra cost. By manufacturing the "harness" using PCB technology, wiring errors as with conventional harnesses can be eliminated. In addition, a reproducible, consistent arrangement of the signal routing is achieved.

The assembly time of the cable harness is drastically reduced by the use of preformed SLIM.flex, and ZIF contacts also eliminate the need to solder the cables or assemble connectors. A SLIM.flex cable harness can also be used as an integrated cable harness in applications with sensitive signals, for example for the smallest image sensors in endoscopes.

SLIM.flex can also be used as a cable assembly.

High-tech Cable Harness

SLIM.flex Design

Relevant Parameters for Production-ready PCB Design

Man sits at two screens and designs circuit boards

Modern printed circuit board solutions are more than just connecting elements. They are the key to progress in electronics. With this in mind, we actively support our customers in development and also offer our own system solutions with electronic functions.

Design Rules

The SLIM.flex Design Rules include all the important parameters you need to make your project successful:

Design Guide

In our Design Guide you will find an overview of all variants of our flex solutions. In addition, our specialists have summarized valuable design tips for you here. This will help you bring your application to success reliably and safely.

SLIM.flex Standard Stackups

Get Started With Your Layout Faster - Thanks to Standardized Stackups

With these stackups, you automatically use market-customary and cost-optimized standards and avoid expensive special setups. They also enable high-quality, cost-effective production with shorter lead times by using stock materials and following standardized production processes.

Here you can find our SLIM.flex standard stackups both in digital form for import into your EDA software, and as PDFs. The digital stackup files for Altium Designer contain not only the stackup but also the material data.

SLIM.flex FAQs

For static applications (IPC-2223 Use A – „flex-to-install“) or dynamical bending applications with little number of bending cycles or uncritical bending conditions ED copper (Electro-Deposited) is standard. RA copper (Rolled-Annealed) is used in dynamic applications (IPC-2223 Use B – „dynamical bending“), applications with several billions of bending cycles are known.

Please note:

  • RA copper has a preferred direction “MD” = “machine direction”. In the other direction the bending capability is remarkably worse
  • In case of flex-rigid with flex layer outside generally also the flexible area is plated – so this copper quality is ED-copper
  • More copper qualities are specified in IPC-4562 standard

No! FR4 materials have PTI / CTI level 3 up to 0 depending on the product (i.e. Nanya NP140 – CTI3 / NPG – CTI 2 / Panasonic R-1655W – CTI 1, just to list some options at least)

But Polyimide, i.e. DuPont Pyralux AP or Panasonic R-F77x only has CTI level 4.

On the other hand almost all designs do not have free copper on the flex layer without a barrier in between like soldermask or coverlay. In addition, in case of flex inside the stackup all copper is completely covered by rigid material in the rigid sections or coverlay in the flexible sections.

Referring to the following table: FR4 dependent on type is then II or IIIa, but Polyimide is IIIb.

Yes, many USB3 cameras use RIGID.flex circuit boards (USB3.1 Gen.2 supports a data rate of 10 Gbps). Important for this is a carefully tuned design with specified impedances. The USB3 specification requires differential lines with 90 Ohm characteristic impedance. We can calculate the necessary design parameters for you, suitable for an adapted layer stack. Usually polyimide cores with a thickness of 75µm or 100µm are used.

Rigid-flex technology offers the following advantages for high data rates:

  • the flex material polyimide is a low-loss material
  • the copper lamination on polyimide has a flat backside which is favourable for high frequency (very flat treatment)
  • RIGID.flex allows the elimination of plugs, which are basically to be regarded as weak points.

Yes, definitely. The advantage is that the thin stackups have only a very small expansion in Z-axis! Tests have shown that even under extreme conditions the circuits are extremely reliable.

In addition to quick samples, we also supply series, gladly also in larger quantities.

Hand Sample WE.scope

Understand Würth Elektronik SLIM.flex Technology Playfully

Learn in detail about the possibilities of SLIM.flex technology in terms of design and applications. The WE.scope hand sample shows the practical implementation of a vision concept from the sensor with illumination and cable harness to the coax connector - and all this in the smallest possible space. This hand sample is available both as a physical hand sample and as a digital hand sample.


"More Powerful Than Ever - The New SLIM.flex Technology"

Ultra-thin. Rugged. Flexible like never before. And on top of that: Available with standards and digital stackups. That is SLIM.flex. The WE Circuit Board Technology PCB of the latest generation.
Find out in our webinar how you can benefit from SLIM.flex and from our competent expert advice as well as a complete delivery process of the PCB from a single source.