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Application: Design guidelines to improve the flexibility and reliability of flexible circuits.
Many of the issues that arise when using a flex circuit come from a lack of knowledge about how to properly design one, especially when the circuit is required to bend. Many novices will design a circuit that calls for bending the flex in too tight of a bend radius, which can cause damage to the circuit and lower the reliability of the end product. This series of articles will focus on the seven key aspects to consider when designing for maximum durability and maximum “flexibility”. It is important to know that because flexibility is a relative term this study will instead use the term reducing bend radius. Below are two of the seven design strategies. Please see Part I and Part III for more tips!
3. Do not allow electroless copper as a seed layer prior to plating vias.
- Also, an area to be concerned about is the type of plating your vendor uses. Some copper plating requires a seed layer of electroless copper. This seed layer becomes an ED copper layer and can lead to conductor cracking. For a tight bend radius direct metallization is the preferred plating method.
4. Use only Polyimide covers in the flexing area.
- There are two options for applying dielectric material over copper:
A. Polyimide cover material: This is the preferred material in areas where parts will be bent. As a general rule, you will want to specify a dielectric thickness and adhesive thickness separately. A rule of thumb is that for every 1 ounce of copper thickness there is 1 mil of adhesive thickness.
B. Flexible Solder Mask: Flexible solder mask has a minimum bend radius of 0.4” and is not recommended for any dynamic flexing application or application where the bend radius will be tighter than 0.4”
ICT Seminar 2023 Review: Energy, Thermals, and Assistive Technology
03/16/2023 | Pete Starkey, I-Connect007
Widely believed to be the traditional Centre of England, Meriden was a popular venue for a gathering of the UK printed circuit community this month. They braved the forecast of heavy snow for the Institute of Circuit Technology’s annual general meeting to learn about current developments and challenges in a thought-provoking technical seminar and to network with industry peers and contemporaries. Thankfully, the forecasted heavy snowfall did not reach Meriden until after the event; we only had a few flurries, although the weather caused considerable disruption elsewhere in the country.
Paige Fiet: Forging a New Path
03/15/2023 | Patty Goldman, I-Connect007
As a young industry professional, Paige Fiet, a process engineer at TTM Logan, sees mentorship as a formative component of her success in IPC. Alongside the support and guidance of her mentors, Paige has distinguished herself as an emerging leader who brings a fresh perspective to the many topics currently of interest to the industry.
IPC APEX EXPO 2023 Special Session: Advanced Packaging
03/13/2023 | Pete Starkey, I-Connect007
The IPC APEX EXPO Special Session on Advanced Packaging this year attracted enormous interest, with Conference Room 2 at capacity long before the session began. Even with lots of extra seats squeezed around the edges, the session was standing room only for the just-in-time arrivals. IPC Chief Technology Officer Matt Kelly opened proceedings by introducing a distinguished panel of experts: Jan Vardaman, president and founder of TechSearch International; Sam Salama, CEO of Hyperion Technology; Matt Neely, director of process engineering at TTM Technologies; and Jim Fuller, VP of engineering technology at Sanmina.