October 19, 2020
With the thinning, multilayering, and increase of substrate-mounted components, especially the development of semiconductor mounting technologies such as BGA. MCM, the substrate is required to have high Tg, high heat resistance and low thermal expansion rate, so as to improve the interconnection of the board. And installation reliability; at the same time, with the development of communication technology and the improvement of computing processing speed, the dielectric properties of substrates have also begun to attract people's attention, requiring them to have lower dielectric constant and lower dielectric loss to meet signal transmission Speed and efficiency.
BT (Bismaleimide-triazine) resin-based copper clad laminate (hereinafter referred to as BT board) has high Tg, excellent dielectric properties, low thermal expansion and other properties, making it a popular high-density interconnect (HDD). It has been widely used in multilayer PCBs and packaging substrates.
"BT" is the chemical trade name of a resin produced by Japan's Mitsubishi Gas Chemical Company. The resin is synthesized from bismaleimide (Bismaleimid, referred to as BMI) and cyanate ester (abbreviated as CE) resin. . As early as 1972, Ling Gas Chemical Company began the research on BT resin. By 1977, BT board began to be used in chip packaging soil, and then they continued in-depth research. By the end of the 1990s, more than a dozen varieties had been developed. , Different products can be made to meet different needs, such as high-performance copper clad laminate, chip carrier board, high-frequency application copper clad laminate, BT resin for packaging, resin-coated copper foil, etc. The demand for this type of sheet in the market is growing day by day.According to the survey results of the sales of various domestic glass cloth-based sheets in 1999 by Japan's JPCA, the sales of BT resin-based sheets are second only to FR-4 boards. , Reaching 36 billion yen.
Because of the importance of BT resin substrate, it has been listed in some authoritative standards in the world, such as EC 249-2-1994 as "No.18" board, IPG4101-1997 as "30" board: MIL-S- 13949H is defined as "GMr board, and the product standard formulated by JIS for this type of product is JS C-6494-1994. my country's national standard GB/T 4721-1992 also defines it as BT" board.
At present, BT boards on the market are dominated by products of Mitsubishi Gas Chemical Company. Only in recent years have some CCL manufacturers launch their BT boards, such as ISOLA and Hitachi Chemical. In China, the industrial production of BT boards is currently blank. However, with the development of the electronics industry and many foreign electronics industry manufacturers investing and building factories in mainland China, the demand for high-performance copper clad laminates in the domestic market is increasing. At present, there are already Research institutes have begun research on BT resin. For example, the BT resin developed by Wuxi Chemical Industry Research Institute has reached a certain level in performance, and Guangdong Shengyi Technology Co., Ltd. has also begun research on this type of sheet.
BT resin performance
BT resin combines the excellent properties of BMI and CE resin. It mainly has the following characteristics: (1) Excellent heat resistance, with a glass transition temperature of 230-330°C;
(2) Excellent long-term heat resistance, with a long-term heat resistance temperature of 160-230°C;
(3) Excellent thermal shock resistance;
(1) Excellent dielectric performance, dielectric constant (er) is about 2.8-3.5, and dielectric loss tangent tan6 is about (1.5-3.0) x10-3;
(5) Excellent electrical insulation performance, even after moisture absorption, it can maintain a high insulation resistance;
(6) Good ion migration resistance, etc.;
(7) Good mechanical properties;
(8) Good dimensional stability and small curing shrinkage;
(9) Low melt viscosity and good wettability;
(1 The shape of the resin varies from old to solid at room temperature, and can be processed by a variety of processing methods;
(1) Soluble in common solvents, such as MEK, NMP, etc.;
(2 It can be modified with a variety of other compounds;
(13 can be cured at a lower temperature;
(1) Compatible with traditional FR-4 production process.
Types of BT resin
BT resin system varies from low-viscosity liquid to solid at room temperature according to the variety and ratio of BMI and CE in its formulation, and the degree of reaction.
The development of current packaging technology, the improvement of the working frequency of electronic equipment and the rapid development of PCB manufacturing technology will provide more extensive opportunities for high-performance BT boards.
1. Development of packaging technology
Traditional semiconductor packaging products: QFP (Quad Flat Package) DIP (Dual Inline Packagil SOP (SmalOutine Package) is to adhere the chip to the metal lead frame, and then use the gold wire to connect the aluminum pad on the chip (AI Pad) and the lead frame Pin. But with the increase in the number of chip pins and the continuous improvement of power requirements, the use of organic substrates with gold wire connection or internal pin (ILB) connection PBGA (Plastic Ball Grid Array) EBGA (En-hanced BGA and Packaging methods such as TAB are increasingly emerging. At the same time, as communication and portable products require miniaturization of component volume, many new technologies such as FC, CSP, WLSCP (WS CSP) multi-chip module (MCM) and ternary bare chip packaging are also increasing. Gradually applied
In Mainland China, with the development of its electronics industry, IC production and market demand are also increasing day by day.
It can be seen that BT resin, as one of the main packaging substrates, will be more widely used in the future packaging field because of its excellent comprehensive performance.
2. High frequency
The development of communication technology and information processing technology has continuously increased its working frequency. For example, the standard of mobile phones has evolved from the original GSM (800-1800 MH2) mode to the current Bluetooth technology (2.400-2.497 GH2); the operating frequency of the CPU processor of the PC has changed from 20-30 in the early 1990s. The development of MHz to the present is close to 1GHZ and the emergence of various digital communications and so on. These fields will put forward higher requirements for the high-frequency characteristics of the plate.
3 Development of lead-free soldering technology
With the increasing global environmental protection calls, the use of lead-free soldering technology in the PCB manufacturing process will gradually become the mainstream, and the higher temperature reflow soldering associated with it will put higher heat resistance requirements on the substrate; at the same time, the production of PCB The direction of thinning, high precision, and high multi-layer development has also put forward high requirements on the heat resistance, dimensional stability, electrical insulation and so on of the substrate.
In summary, due to its good heat resistance, high frequency characteristics and excellent mechanical properties, BT boards will be more and more widely used in packaging substrates, high frequency boards, and high multilayer boards.
HOREXS ，As a thin FR4 PCB manufacturer(IC substrate/Memory card pcb),Almost of their material are BT FR4,which 's from Japan's Mitsubishi Gas Chemical Company,Quality performance is very good.And now Horexs PCB quality can reach to 99.7% is good quality during production.Recommend to you as a thin FR4 PCB partner in the futture.