Components

There are two main considerations when choosing components for Lead-Free assembly:

• That they are capable of surviving the elevated soldering temperatures associated with Lead-Free alloys
• That they have a suitable Lead-Free solderable finish (see next section).

Elevated temperatures

With Lead-Free processes components will often be exposed to higher temperatures than with tin-lead based assembly. If several soldering cycles are used these higher temperatures can intensify thermally related problems. Therefore it is essential that components used for Lead-Free assembly are specified as being Lead-Free compatible i.e. they can survive exposure to higher temperatures without suffering from any immediate or long term reliability issues.

Component damage by exposure to Lead-Free soldering temperatures can manifest itself in a number of ways. The most obvious problems are the immediate catastrophic failures where devices are destroyed during the soldering operation. If it is not possible to ensure higher temperature compatibility, sensitive components may need to be hand soldered after reflow. While some types of immediate failure may be reasonably obvious, it is also possible that exposure to higher soldering temperatures may degrade the performance of components or reduce their in service lifetimes so that an earlier field failure may occur.

For more detailed information on temperature related failures see Faults.