Chip maker NXP Semiconductors NV (NXPI.O) has agreed to buy smaller peer Freescale Semiconductor Ltd (FSL.N) and merge operations in a deal valuing the combined company at over $40 billion. The transaction is the clearest sign yet that semiconductor companies are regaining the confidence required to pursue big mergers and acquisitions at a time when their major clients, such as mobile phone manufacturers, seek to consolidate suppliers. Freescale also has its chips in consumer products such as Amazon’s (AMZN.O) Kindle e-reader.