The new design is a 2-metal COF with a PI thickness of 35 µm (half the thickness of human hair), Cu thickness of 8 µm, a fine pitch of 18 µm, and a line/space distance of 8/10 µm. The general thickness of semiconductor packaging materials is around 150 µmeters or more, LG’s 2-metal CoF is about 70 µmeters thick, which it claims to be the thinnest of its kind.
The specifications for the chip are quite impressive. It has a very thin polymide substrate for the packaging, the fine pitch, the distant between the centers of adjacent pads in the copper is challenging to manufacture, and a very high level of complexity and density. This 2-metal CoF can form more than 4,000 circuits on both sides of the board.
LG Innotek manufactures CoF solutions for displays, including OLED and LCD displays. The company is in competition wiht Stemco, a joint venture between Samsung and Japan’s Toray Industries. It is targeted at flexible displays and will be targeted at XR devices manufacturers in North America and Japan but will probably find its way into smartwatches and flexible mobile devices, too. The technology was originally showcased at CES 2023 in Substrate and Material Zone on LG Innotek’s booth.
