The core of upstream material is substrate
Packaging substrate is the largest cost of IC packaging, accounting for more than 30%. IC packaging cost includes packaging substrate, packaging materials, equipment depreciation and testing, of which the cost of IC carrier board accounts for more than 30%. It is the most expensive in IC packaging and plays an important role in IC packaging. For IC carrier board, the substrate materials include copper foil, substrate, dry film (solid photoresist), wet film (liquid photoresist) and metal materials (copper ball, nickel bead and gold salt). The substrate accounts for more than 30%, which is the largest cost end of IC carrier board.
1) One of the main raw materials: copper foil
Similar to PCB, the copper foil required for IC carrier board is also electrolytic copper foil, which needs to be ultra-thin and uniform, and the thickness can be as low as 1.5 μ m. Generally 2-18 μ m. The thickness of copper foil used in traditional PCB is 18,35 μ M or so. The price of ultra-thin copper foil is higher than that of ordinary electrolytic copper foil, and the processing is more difficult.
2) Two main raw materials: substrate and plate
The substrate of the carrier plate is similar to the copper clad laminate of PCB, which is mainly divided into three types: hard substrate, flexible film substrate and co fired ceramic substrate. Among them, hard substrate and flexible substrate have great development space, while the development of CO fired ceramic substrate tends to slow down.
The main considerations of IC carrier substrate include dimensional stability, high frequency characteristics, heat resistance, thermal conductivity and other requirements:
At present, there are mainly three kinds of materials for rigid packaging substrate, namely BT material, ABF material and MIS material;
Flexible packaging substrate materials mainly include PI (polyimide) and PE (polyester) resin;
Ceramic packaging substrate materials are mainly alumina, aluminum nitride, silicon carbide and other ceramic materials.
Rigid substrate material: BT, ABF, 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 development 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 Wiring is troublesome and laser drilling is difficult, which can not meet the requirements of thin wire, but it can stabilize the size and prevent thermal expansion and cold shrinkage from affecting the yield of wire. Therefore, BT materials are mostly used in networks with high reliability requirements. Chip and programmable logic chip. Therefore, 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 substrate in LED chip packaging is also developing rapidly.
ABF material is a kind of material dominated by Intel, which is used to produce high-end carrier boards such as flip chip. Compared with BT substrate, ABF material can be used as IC with thinner circuit, which is suitable for high pin count and high transmission. It is mostly used for large high-end chips such as CPU, GPU and chipset. As a lamination material, ABF can be directly pasted on the copper foil substrate as a circuit without hot pressing process. In the past, abffc had thickness problems. However, as the technology of copper foil substrate becomes more and more advanced, abffc can solve the thickness problem as long as it uses thin plate. In the early days, ABF boards were mostly used for CPUs of computers and game consoles. With the rise of smart phones and the change of packaging technology, the ABF industry has fallen into a trough. However, in recent years, the improvement of network speed and technological breakthrough have brought new high-performance computing applications. ABF demand is amplified again. From the perspective of industry trend, ABF substrate can keep up with the pace of advanced semiconductor manufacturing process and meet the requirements of thin wire and thin wire width / wire spacing. The future market growth potential can be expected. Due to limited production capacity, industry leaders have begun to expand production.
3) Management information system
MIS substrate packaging technology is a new technology developing rapidly in analog, power IC and digital money markets. The difference between MIS and traditional substrate is that it contains one or more layers of pre packaging structure, and each layer is interconnected by electroplated copper to provide electrical connection in the packaging process. MIS can replace some traditional packages, such as QFN package or lead frame based package, because MIS has finer wiring ability, better electrical and thermal performance and smaller shape.
Flexible substrate material: Pi, PE
PI and PE resins are widely used in flexible PCB and IC carrier, especially strip IC carrier. Flexible film substrate is mainly divided into three layers of adhesive substrate and two layers of non adhesive substrate. At first, the three-layer rubber plate was mainly used for military electronic products such as launch vehicles, cruise missiles and space satellites, and later extended to various civil electronic product chips; The thickness of rubber free plate is smaller, which is suitable for high-density wiring and heat-resistant, The advantages of refinement and refinement are obvious. Products are widely used in consumer electronics, automotive electronics and other fields, which is the main development direction of soft packaging substrate in the future.
There are many upstream substrate material manufacturers, and the domestic technology is relatively weak.
There are many kinds of core materials and substrates for IC carrier plates, and most of the upstream manufacturers are foreign-funded enterprises. Take the most commonly used BT materials and ABF materials as examples. The world’s major hard substrate manufacturers are Japanese companies MGC and Hitachi, Korean companies Doosan and LG and so on. ABF material is mainly produced by Ajinomoto, a Japanese flavor element, and has just started in China.
What are the main materials of packaging substrate
The core of upstream material is substrate