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Climate Change and its Impact on Printed Circuit Boards

Store circuit boards correctly and avoid delamination.
QS information sheet on the storage of printed circuit boards.

Today we would like to give you technical recommendations for the storage of printed circuit boards as a practical handout. This will help you to actively reduce the risk of delamination.
to decrease.

Why is this important right now?
Delamination is a serious problem that is exacerbated by climate change. Global warming is increasing humidity in many regions. Delamination is caused by high temperatures and humidity penetrating the PCB and increasing the gas pressure inside. When the gas pressure exceeds a critical value, the layers burst apart. To avoid delamination, it is therefore essential to store, transport and solder PCBs under controlled conditions.

In Europe, we have had largely natural storage conditions without technical interventions - but the current changes are making a controlled storage environment increasingly unavoidable, as circuit boards absorb more moisture faster and more quickly if they are not stored or transported correctly. In addition, extreme weather events such as heat waves or thunderstorms can lead to sudden temperature fluctuations, which put additional stress on the circuit boards.

Our service for you
Based on our own tests and experience as well as the guidelines of the Central Association of Electrical and Electronic Manufacturers (ZVEI), our experts from production and work preparation have developed a
We have designed a short, one-page handout that summarizes important tips on storing and processing circuit boards.

In order to optimize the overall ordering process for your circuit boards, it is important that you have all the information and specifications available in advance. The more precise and detailed this information is, the smoother and more efficient the production of the circuit board can be.

More detailed recommendations and design rules for the PCB specifications can be found transparently, up-to-date and publicly available in our technical delivery conditions (TLB).

For even greater process reliability, we are also happy to offer shipping in DRY-SHIELD bags and/or drying your circuit boards before delivery.

We hope that our contribution will help you to optimize your PCB storage and reduce delamination. If you have any questions or need further information, do not hesitate to contact us. We are happy to help you.

PS: Of course, we also continuously monitor our own handling of your circuit boards and their storage and downtime in our company to ensure that we meet or exceed the specified values ​​of our technical recommendations.

Storage of PCB (221024 PCP)
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Galvanic Nickel Gold (hard and bond gold)

Also known as hard gold plating. In contrast to the ENIG process, nickel is also used as a diffusion barrier to the copper, but the gold is deposited galvanically, i.e. with an external power source. This means that much thicker layers of 0,8 - 5 µ can be achieved. This "hard gold" is used for circuit boards with connector strips that are plugged in multiple times. The thicker the gold, the higher the number of plug-in cycles (example: 0,4 µ Au = 20 plug-in cycles, 2 µ = 500 plug-in cycles).

OSP (Organic Surface Protection)

OSP is an organic solution that is selectively deposited on solderable copper surfaces with a layer thickness of 0,02 to 0,06 µ using an immersion or rinsing bath. The surface is flat and is well suited for fine SMD assembly. Multiple soldering processes are not possible because the transparent layer decomposes at temperatures above 150 °C.

The shelf life is limited to 6 months.

Chemical silver (chem Ag.)

Chemical silver is a metallic, highly re-solderable surface with a layer thickness of 0,15 - 0,45 µ that is deposited on soldering points without external current (similar to the chemical tin process). The surface is flat and is well suited for SMD assembly.

A storage period of up to 6 months is possible. Similar to chemical tin, the surface loses its solderability due to fluctuations in ambient temperature and humidity. The surfaces must under no circumstances come into contact with materials containing sulphur (such as certain types of wrapping paper).

Chemical tin (chem. Sn)

Chemical tin is a metallic, very easy to solder finish. A thin layer of approx. 0,8 - 1,2 µ tin is deposited without external current on the copper of the soldering points, where it prevents the copper from oxidizing. The surface of the pads is very flat and is therefore particularly suitable for SMD, CoB and HDI and press-fit technology.

The storage time should not exceed 6 months. Humidity and temperature differences during storage can affect the solderability.

ENEPIG (Electroless Nickel Electroless Palladium Immersion Gold)

Between the nickel and gold process steps in the ENIG process, in the ENEPIG process, additional palladium is added as an intermediate layer (0,05 – 0,25 µ thick) into the final surface without external current.

This additional layer is not only ideal for all soldering methods, but is primarily used for gold wire bonding. This process is considered a very expensive special application.

Electroless Nickel Immersion Gold (ENIG)

ENIG or chemical nickel gold is a metallic, very easy to solder finish. It is deposited on the copper layer of the soldering points with a layer thickness of 4 - 9 µ nickel and ideally 0,05 - 0,1 µ gold, which prevents the copper from oxidizing. The deposition takes place without external current using catalytic processes and the electrical potential difference (valence) of the metals used.

The surface is very flat, the multiple solderability is suitable for SMD, Cob and HDI technology as well as aluminum wire bonding and has a storage life of up to 12 months.

The surface is IPC-4552 specified and meets the current requirements of RoHs and WEE.

hot air tinning (HAL = Hot Air Leveling)

The term hot air tinning is used both for the production process and for the surface of printed circuit boards with 99,55% Sn (tin), 0,3% Ag (silver) and 0,15 -0,05% Ni (nickel). It is intended to protect the underlying copper of the soldering points from oxidation.

The circuit boards are immersed in a hot melt (> 260°C) made of the metals mentioned. The surfaces to be tinned are then blown flat with hot compressed air and the holes are blown free. The surface is very suitable for multiple soldering and can be stored for up to 12 months.

HAL is very attractive in terms of quality and price for radial assembly and single-sided SMD technology. Our solder is lead-free and complies with RoHS guidelines.