Device development trends are moving toward more flexible and lightweight form factors. With innovation in materials and components essential to ushering in the metaverse era, LG Innotek's Chip on Film (COF) products are garnering significant attention at CES 2023, emerging as a next-generation innovative component.

LG Innotek announced on the 15th that it is strengthening its strategy to conquer the metaverse market by introducing '2 Metal COF', a product essential for extended reality (XR) devices. LG Innotek said it is targeting the North American and Japanese markets, where many XR device manufacturers are located, while advancing its technology to widen the gap with competitors.

■ 2-Metal COF, slimmed down with highly integrated circuits

2Metal COF is a product that attracted the attention of visitors when it was introduced at LG Innotek's 'Metaverse' corner at CES this year. COF (Chip on Film) is a semiconductor packaging substrate that connects the display and the main board (PCB).

COF minimizes display bezels and facilitates module miniaturization for devices such as TVs, laptops, monitors, and smartphones. Because it requires forming microcircuits on an extremely thin film, advanced technology is required. It is also called an ultra-fine flexible circuit board (FPCB), which can replace existing flexible printed circuit boards (FPCB).

"2-Metal COF" is a technological upgrade of the existing single-sided COF. While existing COFs implemented circuitry on only one side, 2-Metal COF's most notable feature is that it forms circuitry on both sides, resulting in a highly integrated product.

This product has micro-via holes meticulously machined into a thin film and has ultra-fine circuits implemented on both sides, which enables faster transmission of electronic signals and ultra-high-definition screens.

According to LG Innotek, the product's via hole size is 25㎛ (micrometers). Considering that a human hair is 100㎛ thick, this means the hole is one-quarter the thickness of a hair. The smaller the via hole, the more passages there are connecting the top and bottom of the product, and the more pattern circuits that can be created to transmit electrical signals.

■ Perfect for optimizing XR form factors in the metaverse era
With the metaverse era in full swing, demand for flexible and foldable displays has increased, and the components used in these displays also require flexibility. This is why the freely bendable two-metal COF is considered a product that fits the current display industry trends.

LG Innotek's "2-Metal COF" can form over 4,000 circuits by combining both sides of a single unit of film, a limited space. Generally, more patterned circuits lead to better pixels. Higher pixel counts are advantageous for developing XR devices that offer a highly immersive experience.

In particular, LG Innotek applied a new manufacturing technology to reduce the pattern circuit width to a 16㎛ pitch. This reduction, from the original 18㎛, makes it the narrowest in the industry. A smaller circuit width increases the number of pattern circuits that can fit on the COF surface, allowing users to enjoy higher-quality images even on displays of the same size.

LG Innotek emphasized that its 2-metal COF is a thin, flexible film that can be freely folded or rolled. This characteristic reduces the mounting space for the component, allowing set manufacturers to secure more space for components. It helps with the design and planning so that XR devices can evolve further.

In fact, the two-metal COF film thickness is just 70㎛, which LG Innotek explains is the thinnest among semiconductor substrates. This is about half the thickness of typical semiconductor packaging substrates, which are over 150㎛.

To widen the gap with its competitors, LG Innotek is advancing its technology and actively promoting its products in markets like North America and Japan, where many XR device manufacturers are located. Furthermore, the highly integrated circuit implementation technology of the two-metal COF is being applied as a replacement for products that are difficult to achieve on flexible circuit boards, and it is also being developed for applications in new product groups such as microLEDs.

Son Gil-dong, Executive Director of the Substrate Materials Division, said, “Based on the technological capabilities and quality that have driven the substrate business for 50 years, we will lead the two-metal COF market,” and “We will create differentiated customer value with products that can be applied to various applications.”