Apple is expected to unveil the iPhone 15 in September 2023, with minimal changes anticipated in its PCB design. According to research from TrendForce, the iPhone 16, set to launch in 2024, is projected to adopt the use of RCC (Resin Coated Copper) material for its mainboard to reduce the device’s thickness.

TrendForce’s analysis is as follows:

The iPhone 15 Pro Max will feature RFPCB for its periscope lens, while the iPhone 16 Pro series will utilize RCC for its mainboard.

Looking first at the primary changes in the iPhone 15’s PCB, constrained by factors such as device dimensions and product pricing, only the iPhone 15 Pro Max will incorporate a periscope lens. In contrast to the conventional FPC (Flexible Printed Circuit) used in typical lenses, the iPhone 15’s periscope lens will adopt RFPCB (Rigid-Flex Printed Circuit Board) to better utilize space and control the device’s thickness.

Currently, iPhones employ SLP (Substrate-Like PCB) for their mainboards. To achieve a thinner device profile, Apple is planning to introduce RCC as the mainboard material for the iPhone 16 Pro series, scheduled for the latter half of 2024. This will involve using 2 to 8 layers of RCC within the 18 to 20 layers of SLP.

However, based on supply chain information, RCC has not yet passed drop tests, leading to potential fractures between SLP layers. If this issue persists beyond the end of 2023, the adoption of RCC might be postponed until the introduction of the iPhone 17, which could be expected in 2025.

The SLP architecture is moving closer to ABF substrates, while RCC can only replace a portion of the CCL layers.

Taking a closer look at RCC’s material characteristics, RCC involves applying semi-cured epoxy resin onto copper foil after heating. The main distinction between RCC and standard CCL (Copper Clad Laminate) lies in the absence of glass fiber cloth in RCC. RCC primarily consists of resin and copper foil, and it employs ABF (Ajinomoto Build-up Film) instead of PP (Prepreg) as the insulating material between copper foil layers. RCC is also a material used in ABF substrates, indicating that SLP architecture is moving closer to ABF substrates.

Due to its lack of glass fiber cloth, RCC offers advantages such as reduced thickness and suitability for fine line designs. Its lower Dk (Dielectric constant) and Df (Dissipation Factor) characteristics contribute to high-frequency and high-speed transmission. However, due to its softer nature, RCC has poorer support capabilities, allowing it to only replace certain CCL layers.

It is expected that Ajinomoto will have a monopoly in the iPhone RCC market in 2024, with Taiwanese manufacturers potentially becoming suppliers in 2025.

In the supply chain realm, since ABF substrates also involve RCC, Ajinomoto, a primary ABF supplier, is projected to become the exclusive supplier of iPhone RCC materials in 2024. ITEQ, an early adopter of RCC materials, successfully developed RCC production lines by the end of 2021, making it the first Taiwanese CCL manufacturer to do so. As such, it stands a chance of becoming the second supplier.

EMC is a major supplier of iPhone mainboard CCL materials, with an estimated market share of around 95% in 2023. TSEC also successfully developed RCC materials in 2022, indicating that both ITEQ and EMC have potential to enter the iPhone RCC supply chain in 2025. Other companies, including Japanese firms Mitsubishi Gas Chemical, Panasonic, and Korean company Doosan Electronics, have also developed RCC materials, indicating an interest in becoming part of the iPhone RCC supply chain.

TrendForce’s investigation into the supply chain reveals that Apple plans to upgrade the PCB materials in its new iPhone models in 2024. The current copper-clad laminate (CCL) will be partially replaced with resin-coated copper (RCC), aiming to reduce the size and thickness of the mainboard. This upgrade is expected to enhance electronic signal transmission efficiency, reduce energy consumption, and save internal space, providing more room for increased battery capacity.

Apple first introduced the substrate-like PCB (SLP) with the launch of the iPhone X in 2017. SLP offers advantages over conventional high-density interconnect (HDI) PCBs by reducing line width and spacing, optimizing PCB area, and increasing battery space. This design has remained unchanged since its introduction. However, recent discussions within the supply chain indicate that there are plans to introduce RCC materials in the second half of 2024 for the upcoming iPhones, marking an upgrade after a seven-year gap.

The main difference between RCC and traditional CCL lies in their structure. RCC eliminates one layer of fiberglass cloth, significantly reducing the overall thickness of the PCB. It also simplifies the manufacturing process and improves the laser drilling yield. In terms of component performance, RCC allows for further reduction in line width and spacing of circuit wiring based on SLP, reducing the spacing between various passive and active components on the board. It even enables the embedding of some passive components, thereby saving space required for surface mount technology (SMT) processes. All these upgrades contribute to greater power efficiency and improved performance in end devices.

Considering the similarities between RCC and ABF substrates in terms of the manufacturing process, the most likely supplier for RCC is the Japanese company Ajinomoto. If Apple successfully replaces some layers with RCC in 2024, it may impact the demand for existing CCL, particularly affecting the CCL supplier, Elite Material (EMC). It is anticipated that EMC’s RCC product may require 1-2 more years of research and development before it has a chance to be completed.

For more information on reports and market data from TrendForce’s Department of Semiconductor Research, please click here, or email Ms. Latte Chung from the Sales Department at lattechung@trendforce.com