Elimination of Non-stick on Leads Defect through Re-designed WCTP
Richard G. Mariano
STMicroelectronics, Inc., Calamba City, Laguna, 4027, Philippines.
Alyssa Grace S. Gablan *
STMicroelectronics, Inc., Calamba City, Laguna, 4027, Philippines.
Frederick Ray I. Gomez
STMicroelectronics, Inc., Calamba City, Laguna, 4027, Philippines.
*Author to whom correspondence should be addressed.
Abstract
This paper presents the reformation and fabrication resolved on the wire clamp and top plate (WCTP) design to eliminate the presence of lead finger bouncing resulting to high rejection of non-stick on leads (NSOL). Problem experienced was that the hollow or half-etched portion of the leadframe at the top and bottom units caused its bouncing effect. With the aim to improve localized massive NSOL defect, WCTP has been modified to provide positive bias to support its hollow part or the half-etched part of the leadframe at the top and bottom of the units. The re-designed WCTP was fabricated, extending its clamping with enhanced vacuum on top and bottom rows. The implementation of the improved WCTP design reduced the defect with 88 % improvement with the defect reduction during the lot runs.
Keywords: Bouncing, non-stick on leads, wire clamp and top plate, wirebond