Hard substrate materials: introduction to BT, ABF and MIS

1. BT resin
The full name of BT resin is “bismaleimide triazine resin”, which is developed by Mitsubishi Gas Company of Japan. Although the patent period of BT resin has expired, Mitsubishi Gas Company is still in a leading position in the world in the R & D and application of BT resin. BT resin has many advantages such as high Tg, high heat resistance, moisture resistance, low dielectric constant (DK) and low loss factor (DF). However, due to the glass fiber yarn layer, it is harder than the FC substrate made of ABF, troublesome wiring and high difficulty in laser drilling, it can not meet the requirements of fine lines, but it can stabilize the size and prevent thermal expansion and cold shrinkage from affecting the line yield, Therefore, BT materials are mostly used for network chips and programmable logic chips with high reliability requirements. At present, BT substrates are mostly used in mobile phone MEMS chips, communication chips, memory chips and other products. With the rapid development of LED chips, the application of BT substrates in LED chip packaging is also developing rapidly.

ABF material is a material led and developed by Intel, which is used for the production of high-level carrier boards such as flip chip. Compared with BT substrate, ABF material can be used as IC with thin circuit and suitable for high pin number and high transmission. It is mostly used for large high-end chips such as CPU, GPU and chip set. ABF is used as an additional layer material. ABF can be directly attached to the copper foil substrate as a circuit without thermal pressing process. In the past, abffc had the problem of thickness. However, due to the increasingly advanced technology of copper foil substrate, abffc can solve the problem of thickness as long as it adopts thin plate. In the early days, most of the CPUs of ABF boards were used in computers and game consoles. With the rise of smart phones and the change of packaging technology, the ABF industry once fell into a low tide. However, in recent years, with the improvement of network speed and technological breakthrough, new applications of high-efficiency computing have surfaced, and the demand for ABF has been enlarged again. From the perspective of industry trend, ABF substrate can keep up with the pace of semiconductor advanced potential, meet the requirements of thin line, thin line width / line distance, and the market growth potential can be expected in the future.
Limited production capacity, industry leaders began to expand production. In May 2019, Xinxing announced that it is expected to invest 20 billion yuan from 2019 to 2022 to expand the high-order IC cladding carrier plant and vigorously develop ABF substrates. In terms of other Taiwan plants, jingshuo is expected to transfer class carrier plates to ABF production, and Nandian is also continuously increasing production capacity. Today’s electronic products are almost SOC (system on chip), and almost all functions and performance are defined by IC specifications. Therefore, the technology and materials of back-end packaging IC carrier design will play a very important role to ensure that they can finally support the high-speed performance of IC chips. At present, ABF (Ajinomoto build up film) is the most popular layer adding material for high-order IC carrier in the market, and the main suppliers of ABF materials are Japanese manufacturers, such as Ajinomoto and Sekisui chemical.
Jinghua technology is the first manufacturer in China to independently develop ABF materials. At present, the products have been verified by many manufacturers at home and abroad and have been shipped in small quantities.

MIS substrate packaging technology is a new technology, which is developing rapidly in the market fields of analog, power IC, digital currency and so on. Different from the traditional substrate, MIS includes one or more layers of pre encapsulated structure. Each layer is interconnected by electroplating copper to provide electrical connection in the packaging process. MIS can replace some traditional packages such as QFN package or leadframe based package, because MIS has finer wiring ability, better electrical and thermal performance, and smaller shape.