A Dual Imaging System for Flip-Chip Alignment Using Visual Servoing

Abstract

Electronic components must be precisely aligned on printed circuit (PC) boards in chip packaging, especially in flip-chip assembly. We propose a vision system to provide relative positioning information between the flip-chip and substrate to ensure accurate alignment. The dual imaging system (DIS) we introduce to ensure alignment consists of a zoom lens, beam splitter, mirror, charge-coupled device (CCD) and light-emitting diode (LED) illumination, and simultaneously observes solder bumps on flip-chips and pad patterns on substrates using one camera. Features are extracted from the preprocessed image frame containing the flip-chip and substrate to obtain positioning and orientation errors between the chip and substrate. Based on measured error, visual servoing determines the instantaneous velocity input of flip-chips at each servoing iteration time and controls relative positioning and orientation precisely on-line. Fine servoing on a 3-axis stages uses dual imaging for visual alignment. Experiments under different parameter conditions to evaluate dual imaging system and visual servoing algorithm performance confirmed the feasibility of our proposal.

Visual Servoing for Underwater Vehicle Using Dual-Eyes Evolutionary Real-Time Pose Tracking

“…Then, the techniques are differentiated based on the number of cameras; from single to multi cameras. Even though there are some limitations for real-time applications in terms of image-acquisition-quantization accuracy and processing rates, the role of visual information has been expanding rapidly in industry and human society in line with efforts of researchers [4,5].…”