Immersion tin process

The chemical tin process is operated in a horizontal way. The Stannatech 2000H processing chemistry by Atotech provides the basis here. Through the appropriate know-how we keep the process-related components as tin (IV+) compounds, copper and other decomposition products in the tin layer deposited as low as possible. This is an important component to achieve a perfect soldering result.

In our immersion tin a content of >98.5% tin is included. A small amount of a special additive (AWA) in the tin layer prevents the development and growth of whiskers which is proved through various analysis and long-term tests. The AWA content in the process is permanently monitored. This is only one part of the process to obtain an excellent wettable chemical tin layer which can also be soldered repeatedly.

Pcbs with blind holes and laser drillings (up to 150 µm; AR 1:1) can be rinsed residue-free through a special rinsing concept. Contamination measurements show values of significantly <1.55 µg/cm² NaCl-Equivalent.

Would you like to obtain more technical details?
Send us an e-mail to:  bestellung(at)hofstetter-pcb.de

X-ray layer thickness measurement

The layer thickness of each order will be controlled by x-ray measurement. APL Hofstetter works with the XULM device (Win FTM with the application of chemical tin/ copper) made by Fischer Messtechnik. Measurements are carried out on a regular basis to receive an excellent measurement accuracy and reproducibility.

Immersion tin as a substitute

HAL (leaded or lead-free hot air levelling)

Hot air levelling (HAL) is a favored and cost-effective soldering surface which is still used often in practice. HAL will reach the technical limits (fine pitch) if it's necessary to coat very fine structures. In addition process-related errors can occur which are undesirable in assembly.

As well as:
Increased costs through optical checking (solder bridges and balls)
Increased testing costs through E-testing (pseudo-faults)
Failure rate through thermal stress (through twisting and warping)
Rejects through imprecise soldering
Measlings or delaminations in the base material
Increased copper removal in the drillings

Using our immersion tin process the errors and problems mentioned above cannot even occur.

It's our pleasure to offer you advice on the technical opportunities.

 

Gold layer systems

If a gold layer system (ENIG/ ENEPIG) is not required as a contact or bond surface it is not necessary to use those neither from a financial nor technical point of view. ENIG and ENEPIG general shows disadvantages as:

high cost of gold
input of foreign metals (nickel and gold) in the soldered joint
black pad defects
the risk of nickel plating on the solder resist mask

With our immersion tin you do not have the disadvantages mentioned. These cannot occur through process-related factors. Further more you can achieve significant cost saving.