What layer thicknesses can APL handle?

Depending on the customer requirement and order, APL place layers of 0.8 µm, 0.9 µm and 1.0 µm with a cpk value of 1.333. Layer thicknesses of 1.1 µm and 1.2 µm can also be handled; here the smallest layer thickness will be the same as the ordered layer thickness.

To the top

How is the layer thickness measured?

The layer thickness is measured using an x-ray measuring device (produced by Fischer XULM), non-destructively and without comparison factors (in conformity with Siemens).

To the top

How fast can APL handle smarttin® orders?

In general, depending on the size of the batch, goods which are delivered to APL up to around 9 a.m. are processed on the same day. For the most part this orders can leave our factory on the same day, depending the logistic is accurately defined.

In very urgent cases, the goods can be delivered by courier after prior consultation and the appropriate application. We like to schedule a time frame so that the courier can take back the express orders after a waiting time.

To the top

How does APL deliver goods?

APL uses all the usual package services (UPS, DHL, DPD, FedEx, etc.) depending on the customers requirements. UPS and Dachser are the companies own regular providers. If so required, the special conditions given to APL can be used.

To the top

How are pcbs packaged after tin plating at APL? 

Pcbs up to a size of ca. 400 mm x 400 mm are packaged in environmentally friendly polypropylene shrink wrap. Larger formats are usually already delivered in special transport racks or trays. APL generally uses the original packaging. Special packaging requirements can be considered (environmentally neutral packaging, labeling, etc.).

To the top

Can APL carry out a tin stripping process on pcbs that have already been tin plated?

APL cannot strip off Sn. For the refresh a tin strip process is not necessary. The refresh process has been proved to function through renewed deposition of chemical Sn on the tin layer already present (the “tin on tin” process). Certainly fundamental errors in the tin layer cannot be eliminated to 100%. If a stripping process is necessary, APL will use the external service providers for this.

To the top

What are the reasons in favor of the refresh process?

Through the refresh process, an unsolderable pcb stored for an extended time will be brought into functioning capacity again. Light drying stains and discolorations are eliminated to a large degree. General errors present in the tin layer such as, for example, contamination or tin whiskers may nevertheless in some cases require Sn stripping of the first tin layer. Tin plating will be possible again, but there is a risk of solder mask lifting through strain on the solder resist mask. In such cases, APL always recommends a preliminary test.

To the top

Which solder resists are compatible with the smarttin® process?

Experience has shown that all usual solder resists such as those from, for example, the companies Huntsman, Peters, and Coates are resistant, as long as these are applied in conformity with the manufacturers instructions. Gladly APL will check resistance for you in the course of production.

To the top

Can pcbs with carbon coating or varnish be tin plated?

Carbon coating or varnishes can be processed easily. For this we suggest to run sample trials.

To the top

Is smarttin® whisker-free?

Through the use of a specific additive in the chemical Sn bath, whisker formation (according to the IPC definition) is prevented. Evidence of this was already brought in 2003 by our partner, Atotech Deutschland GmbH in cooperation with renowned industrial firms.

To the top

What processing time is guaranteed by APL for smarttin®?

APL guarantees a processing time of 12 months with layer thickness of 1.0 µm (cpk = 1.333) (storage conditions: >15 °C to 30 °C at 60% relative humidity, dewing of the pcbs is excluded).

To the top

What surface finish does the copper have to feature on delivery?

The copper surfaces have to be free of varnish, developer residues, oil, fat, and condensates from the varnish hardening process. Very strong copper oxides layers (violet-black discoloration) cannot be 100% cleaned and are therefore to be avoided. Artificially produced copper oxide layers for improvement of the solder resist mask adhesion (FerroEtch, etc.) can easily be removed in the two-step preliminary cleaning process.

To the top

What surface contamination is measured after smarttin® processing on the pcbs?

Depending on the solder resist mask used in addition to how it has been processed, values of <0.5 µg/cm² NaCl-Equivalent have been measured in practice. 1.56 µg/cm² NaCl-Equivalent (analogous to IPC) is regarded as the upper limit.

To the top

Is smarttin® comparable to HAL in terms of resilience and processing quality?

smarttin® is superior to the HAL surface in many reasons especially with regard to the planarity of the surface. Heat stress on the basis material as well as the solder resist and possibly increased copper removal cannot occur through the process using smarttin®.

To the top