With the rapid development of microelectronics technology, the widespread application of large-scale and ultra large scale integrated circuits, and the advancement of micro assembly technology, the manufacturing of printed circuit boards is moving towards

Lead-free means no lead (chemical symbol Pb) in packaging or product manufacturing. In IC packages, Pb is common in external pin polishing or plating. For wafer level packaging (UCSP and flip chip), Pb appears on the solder balls.

Google has hardly publicly disclosed the specific factors that affect its search engine ranking, so when it announced in August last year that adopting the HTTPS encryption protocol is beneficial for search engine ranking, my mood was one word: shocked! H