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→Electroless Metal Deposition on Printed Circuit Boards
== Wire Bonding==
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== AlSi Clad Strip for Bond Connections==Besides electroplated or chemically deposited gold coatings, AlSi clad semi- finished materials are used for layered systems on circuit carriers and in hybrid housings (or for lead frames). These strip materials are manufactured by cold roll cladding of an AlSi1 alloy material onto Cu or Cu alloy strip (<xr id="fig:Examples of AlSi clad strips for bond connections"/>) (see chapter [[Manufacturing_of_Semi-Finished_Materials|Manufacturing of Semi-Finished Materials]]).
To achieve a strong metallurgical bond between these two components, a suitable surface preparation of the carrier strip and a high degree of deformation are required, followed by diffusion annealing of the clad strip.
Depending on the requirements of the assembly technology for the final product, i.e. using connectors or soldering attachment, the clad strips are coated in the terminal area with a suitable surface layer with either an electroplated hard gold (AuCo0.3) layer or selectively by electroplating or hot dip tinning with pure tin or a tin alloy. To ensure the best bond properties during the coating process, the AlSi surface is protected against corrosion by masking during this processing step.
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[[File:Dimensions typical-values.jpg|left|Dimensions (typical values)]]
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Mechanical strength and dimensional tolerances for AlSi clad strips mostly follow the standards EN 1652, EN 1654, and EN 1758 for Cu and Cu alloys. Depending on the end application the following parameters for the coating layer are tested for and documented during manufacturing:
*Solderability
== Electroless Metal Deposition on Printed Circuit Boards==
Printed circuit boards are also used as circuit carriers. Since many of the conductive structures on the PCB are not electrically connected, the final surface coatings are produced using an electroless process (<xr id="fig:Electroless deposition on a printed circuit board"/>). (Chapter [[Electroless_Plating|Electroless Plating]]). Besides bonding to Nickel/Gold surfaces, soldering is the most widely used process to create conductive connections. This can also be performed on electroless deposited tin surface coatings.
<figure id="fig:Electroless deposition on a printed circuit board">
[[File:Electroless deposition on a printed circuit board.jpg|right|thumb|Figure 23: Electroless deposition on a printed circuit board]]
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