Manual bidirectional dislocation flip chip alignment technology based on image preprocessing

High-precision bonding of flip-mounted chips is the key technology of advanced packaging of integrated circuits, and the up-down camera technology currently used has problems such as large Z-height difference and camera motion errors. In this paper, the up-down camera is divided into two cameras, and a new high-precision flip chip alignment method is proposed by using virtual image preprocessing technology, which can greatly reduce the z-direction motion stroke of the placement head and reduce the accuracy error. Aiming at the mechanical structure characteristics of the short-range bidirectional dislocation flip bonding system, a device for evaluating the alignment accuracy is designed, which is called the characteristic parameter mask. Based on this error evaluation system, a chip alignment error model is established, an image virtual alignment method is proposed, and the alignment accuracy of the new method is analyzed. An optical alignment system was built to correct the sub-micron alignment mark for auto-tuning to verify the effectiveness and reliability of the preprocessing of images acquired by the bidirectional misalignment camera. Experimental results show that the proposed method can be applied in high-precision manual flip chip alignment, which can shorten the bonding distance to the sub-micron range, and the alignment accuracy can reach less than 0.7 microns, which meets the requirements of accuracy, adaptability and real-time alignment of wafer and chip flip bonding.