Author: John Maxwell Company: JMA Date Published: 9/12/1996
Surface Mount International
Abstract: Cracks in ceramic surface mount technology(SMT) components limit assembly reliability and yields. These cracks manifest themselves as electrical defects; intermittent contact, variable resistance, loss of capacitance or excessive leakage currents over time. Large visible cracks and the insidious micro crack are usually blamed on the soldering process by component vendors and on the components themselves by the users. The actual sources of cracks do include both to a lesser extent but other very significant crack sources exist. Cracks can be introduced at any process step used to manufacture an assembly. These sources include thermal shock, pick and place machine centering jaws and vacuum pick up bit, board depanelization, handling assemblies after soldering, test fixtures, connector installation, and final product assembly.