The EMPF Boot Camp covers a wide range of course modules designed to provide participants with a basic knowledge of electronic manufacturing processes.  The focus of this article is on the contents of the Cleaning module offered during the Boot Camp course.  Students will gain an understanding of the concerns about cleanliness and residues common with electronic devices, the types of residues that are considered benign or harmful, the various cleaning chemistries and processes, safety issues and the most commonly used cleaning equipment. 

One of the main reasons for cleaning residues left on electronic assemblies is to prevent corrosion of the components and boards.  Improperly cleaned assemblies can also create problems other than corrosion.   Specifically, the insulative properties of a board can be altered due to residue, the adhesion of conformal coating can be affected, or the residue may interfere with moving parts on the assembly. In some applications like RF, flux residue can change the RF properties (e.g. dielectric strength, surface resistance, Q-resonance, etc…) of the surface of the PWA.

Students will learn how to identify the commonly used processing materials considered harmful or corrosive and will learn the problems associated with contaminants left on a finished assembly.

Choosing a cleaning process involves understanding what is acceptable, either by meeting a cleanliness standard, using visual acceptance, or both. Identifying the type of contaminate to be removed will determine the type of cleaning materials. The through-put and specific manufacturer’s limitations (e.g. disposal, space, auxiliary utilities, etc…) will dictate equipment choice. Students will learn about some of the more common equipment and chemistries used to clean electronic assemblies, in addition to the common incompatibilities between chemistries, equipment and materials used for cleaning assemblies.  The following
techniques - Solvent/Co-Solvent, Semi-Aqueous, Aqueous,
DI Water, Emulsion and Plasma cleaning, will be compared and contrasted during the course, along with the following
equipment - Batch Cleaning, In Line Cleaning and Ultrasonic Cleaning. The key process parameters/requirements for each technique/equipment will be discussed.

This course provides an overview of technologies available, and the ultimate goal is to ensure that the chemistries and equipment will remove the contaminants without degradation or damage to the product.