SMT, PCB Electronics Industry News

Bonding Flip Chips on to Flexible Circuit Boards

Jan 18, 2011

Würth Elektronik’s unique ESC process enables flip chip bonding on the most varied of substrates, even on flexible materials such as polyimide films and LCPs (liquid crystal polymers).

Würth Elektronik’s unique ESC process enables flip chip bonding on the most varied of substrates, even on flexible materials such as polyimide films and LCPs (liquid crystal polymers).

Time and again, a major challenge lies in attaching integrated circuits (ICs) to highly integrated circuit board substrates in a space-saving manner. Würth Elektronik took this challenge on and found an ideal solution with the ESC (encapsulated solder connection) process. The chips are soldered and at the same time glued 'face-down" in their exact position. The ESC process is suitable for the most diverse substrates, be they fragile glass materials, FR4 or even flexible materials such as polyimide foils or LCP (liquid crystal polymer).

As the result of a unique adhesion soldering process, Würth Elektronik is able to put flip chips on different circuit board substrates – even on flexible materials

Each substrate represents a separate challenge. Depending on the substrate, extremely tiny pitch distances of less than 100 µm can be realized. Using thermal compression bonding technology, the upside-down chip (flip chip) is set onto an anisotropic adhesive containing microscopic soldering particles. Briefly heating the adhesive causes the solder particles to melt and results in a true soldering connection between the chip's contacts and the substrate, which creates the electrical contact. The simultaneous hardening of the epoxy adhesive also sets the flip chip firmly into place. The entire process is called flip chip bonding. "An additional 'underfill process' is not required. In particular, the high exactness of placement and the finely dosed bonding force make it possible to process even extremely brittle substrates without any problems," explains Roland Schönholz, who is responsible for bonding technologies and Lasercavity at Würth Elektronik in Schopfheim, Germany.

At first glance, it seems contradictory to place relatively brittle ICs on flexible circuit boards. The ESC process, however, masters this challenge as well. The right chips are the prerequisite for successful bonding of the flip chips. These chips should have gold stud bumps, galvanic bumps or similar means of contact to serve as contacts. Würth Elektronik is able to manufacture the gold bumps itself for small amounts of individual ICs or also for small runs.

The ESC process gives the user great latitude in selecting the correct substrate – anything is possible, from brittle to flexible. The decisive factor, however, is that the final surface on the substrate can be soldered. "We are able to demonstrate that we have experience working with all common surfaces such as chemically applied silver, chemically applied zinc, ENIG (electroless nickel immersion gold) or ASIG (autocatalytic silver immersion gold)," says Roland Schönholz, "because numerous tests have already proven the reliability of the new construction and connection technology." In addition, flip chip bonding has already been proven in real life in connection with the innovative Lasercavity method, which Würth Elektronik is pioneering. With the bonding of flip chips, the circuit board specialist is continuing its technological leadership and enables users to further miniaturize its products and to achieve a maximum of integration while maintaining reliable functionality.

Jan 30, 2014 -

Certified once again: The Quality Management System of the Würth Elektronik certified to the automotive standard ISO/TS 16949

Jan 22, 2014 -

Informative & Interactive - PCB webinars from Würth Elektronik

Dec 10, 2013 -

HDI Microvia PCBs now available online at WEdirekt

Sep 03, 2013 -

Printed Circuit Boards from Asia: Würth Elektronik opens office in China

Jun 25, 2013 -

FESTO Elite Supplier Award 2012 for Würth Elektronik

Jun 03, 2013 -

Würth Elektronik Expands its Service Portfolio

Jan 22, 2013 -

Würth Elektronik partnering with RS Components

Oct 19, 2012 -

WEdirekt – The Online Shop For Printed Circuit Boards and Stencils

Jun 20, 2011 -

Würth Elektronik is first PCB producer in Germany receives seal of approval „AEO F, Authorised Economic Operator (Full) “

May 05, 2010 -

Würth Elektronik offers the best contact between flex-rigid PCBs and ZIF connectors

2 more news from Würth Elektronik GmbH & Co. KG »

Jun 18, 2018 -

Online SMT Auction July 5th – July 11th, 2018

Jun 17, 2018 -

SMT Nuremberg Pays Off for Europlacer & Speedprint.

Jun 17, 2018 -

Libra Industries’ Christopher R. Howell Memorial Foundation Awards $22,500 in Scholarships during Annual Golf Outing

Jun 17, 2018 -

New Low-Temperature Solder Paste from SHENMAO

Jun 17, 2018 -

Jeremy Zhou Appointed to China Regional Sales Manager for VJ Electronix, Inc.

Jun 17, 2018 -

IPC’s PCB Technology Trends Study Underway, OEM Survey Open Until July 6

Jun 17, 2018 -

Join Scienscope this Week at the SMTA Upper Midwest Expo

Jun 17, 2018 -

IPC Hand Soldering Regional Qualification Competition Winner Crowned at SMT Hybrid Packaging 2018

Jun 17, 2018 -

DDM Novastar Welcomes New Director of Engineering

Jun 17, 2018 -

VJ Electronix Announces New Eastern Regional Sales Manager for the Americas

See electronics manufacturing industry news »

Bonding Flip Chips on to Flexible Circuit Boards news release has been viewed 5 times

used pcb assembly equipment - lel semi

fluid dispensing robots - techcon