Understanding the Cause and Effect of Bent Side Rail in Molding Process
Mariane Mendoza
STMicroelectronics, Inc., Calamba City, Laguna- 4027, Philippines.
Maria Virginia Buera
STMicroelectronics, Inc., Calamba City, Laguna- 4027, Philippines.
Joel Pablo
STMicroelectronics, Inc., Calamba City, Laguna- 4027, Philippines.
Jerome Dinglasan *
STMicroelectronics, Inc., Calamba City, Laguna- 4027, Philippines.
*Author to whom correspondence should be addressed.
Abstract
During processing of Quad Flat No-lead (QFN) on the production line, it has been observed that strips were found with bent rails after the molding process. Mold is a process in the semiconductor industry where package encapsulation happens by filling the cavities with molding compound, depending on the required package thickness. Succeeding processes of post-mold cure, strip etching, and laser marking were not affected by the encountered bent rails at mold but singulation process feedback that the affected strips prompted jig alignment errors which prevents the strip to be successfully auto processed at jig saw singulation. The problem on hand have encouraged the authors to understand the cause of bent rails thru process mapping and validation of its effect on the downstream processes.
Keywords: Jig alignment error, mold process, bent side rail, QFN, transfer mold