The market for system-in-package (SiP) substrates is already tight and will become tighter as Apple is looking to adopt SiP technology in more of its AirPods series, according to sources at Taiwan-based IC substrate suppliers.

Charging adapters and wired earbuds are not available with just-unveiled iPhone series, deemed partly to promote sales of wireless AirPods and partly to reduce actual materials and environment costs, the sources said, adding that Apple is reportedly to adopt SiP+ flexible PCB solution for its next-generation AirPods to further cut production cost for the TWS earbuds. The solution is now only applied to the AirPods Pro series.

Demand for SiP substrates to process AirPods chips has been ramping up steadily, as shipments of AirPods Pro have risen to the same level in 2020 for AirPods 2 adopting rigid-flex boards from just half the level in 2019, the sources said.

Taiwan's Nan Ya PCB and Kinsus Interconnect Technology, both supplying SiP substrates for AirPods Pro series, are expected to land more orders in 2021 from Apple along with the launch of new-generation TWS earbuds and increasing sales of existing AirPods Pro models, the sources continued.

It is estimated that demand for SiP substrates may grow 30% in 2021, and both Nan Ya and Kinsus have disclosed plans to slightly boost capacity next year. But another Taiwan maker Unimicron has no plans to follow suit in this segment and will focus on capacity expansion for ABF substrates for processing high-end GPU, CPU, server and networking chips, the sources said.