With the rise of smart devices, applications for semiconductor components are quickly expanding. The requirements for chip size, information transmission speed, and power in network communications, automotive applications and manufacturing are also becoming more stringent. However, traditional packaging methods cannot keep up with the new market demands. Therefore, wafer level packaging and Fan Out Panel Level Packaging (FOPLP) have gradually become the focus of 5G, AIoT and high performance computing (HPC) companies when purchasing chips. Redistribution layers (RDL) is a core technology during the production of these chips, an it has also become a key area of focus of the industry in recent years. However, FOPLP demands a relatively high level of customization in its equipment. The Vice President of Sales at Manz, Adam Jian, stated that companies who intend to introduce this technology must focus on design and integration verification when selecting an equipment supplier.
The Director of Technology at Manz, Dr. Eric Lee, explained the importance of RDL to semiconductors. He pointed out that the size of semiconductors is quickly decreasing. Traditional wire bonding and flip chip packaging can no longer be applied to these smaller chip sizes to improve the efficiency of electronic systems. Therefore, the company developed Fan-In WLP for packaging on wafers, achieving the goals of miniaturized packaging and lowering costs. Although Fan-In WLP possesses the advantages described above, there are still many potential problems during production. The biggest challenge is with soldering. If existing solder balls are used, the dimensions of these solder balls make it impossible to place them on miniaturized chips. On the other hand, the use of smaller solder balls would incur additional costs. In order to solve this problem, semiconductor companies began developing Fan-Out packaging.
The technology is split into Fan Out Wafer Level Packaging (FOWLP) and Fan Out Panel Level Packaging (FOPLP). FOPLP has become the focus of the market due to its suitability for mass production and miniaturization and its low cost. Dr. Eric Lee stated that currently chip substrates still use organic materials. Because 10 microns is the limit for wire production and the size stability is relatively poor, producing thin circuits on the substrates is relatively difficult. Panel level RDL uses comparatively less material, therefore the thickness can be greatly reduced to between 2 to 10 microns. Alongside the large surface area glass substrate production technology, the packaging process can provide thin circuits and cover large surface areas. He compared FOWLP and FOPLP, which both use RDL technology for packaging. FOPLP can be used for 500mm x 500mm or 600mm x 600mm surface areas, which are 4 to 6 times larger than the current 300mm x 300mm wafer substrate. Therefore, it can provide cost advantages to companies with high yield rates and good integration capabilities.
Regarding integration, Dr. Eric Lee also stated that it is another advantage of FOPLP. Currently, chips that use RDL for integration include power chips, radio frequency chips, base band chips and application processors with high pin counts in mobile phones. Additionally, in order to provide compact sizes and high efficiency, the applications of System in a Package (SIP) are quickly increasing, and the thin circuits and large surface area of FOPLP can satisfy the needs of SIP. He mentioned that the constantly miniaturizing semiconductor production process is nearing its physical limits. Therefore, packaging is now regarded as an area of focus for extending Moore's Law. RDL can help SIP conduct heterogeneous integration. In future 5G and AI integrated application electronics, MCUs, memory, and other digital computing components and sensors can be integrated, thereby reducing the signal transmission distance. Additionally, the thinner packaging can help with heat dissipation, thereby providing better efficiency and performance than existing packaging methods.
Although FOPLP has many advantages, it is difficult for semiconductor companies to introduce the technology. The current wafer level packaging used by the companies has different surface areas and materials compared to FOPLP. Therefore, it can easily cause warping in the boards, uneven coatings, and other problems. Furthermore, because the packaging sizes have not been standardized, the production processes of each packaging company are different. Companies must find their own solutions and suitable equipment. Therefore, in the semiconductor RDL production equipment sector, Manz is focused on designed services, which can satisfy the need for customization in the market. However, Adam Jian specifically pointed out that semiconductor companies do not only require a single machine for FOPLP, instead they need a partner who can provide turnkey solutions. He stated that to reach the mass production standards for FOPLP yield, companies need more than RDL packaging equipment. The surrounding machinery must also support the functions. He used the coating process as an example. Uneven coating has always been a big problem for packaging companies. In response to this problem, Manz developed patented technologies for electroplating equipment, which can provide a coating evenness of 95%, greatly improving the yield and efficiency of production.
Adam Jian said that Manz has been deploying FOPLP technology for many years and started offering related services in 2015, and has successfully applied this technology in real-world applications. Besides semiconductor companies, other companies have also incorporated the technology in recent years. For example, LED companies plan to use panel level packaging to electroplate circuits onto glass, optimizing the performance of MiniLED displays. Passive component suppliers hope to use the capacity and inductance of the product to expand the application scope. Facing the diverse needs of the market, Adam Jian stated that besides continued investments in technology development, in the future, Manz will actively expand the reach of its partnerships to help companies in different fields construct high performance FOPLP production systems, seizing the numerous opportunities in smart devices.
Vice President of Sales at Manz, Adam Jian (left) and Director of Technology at Manz, Dr. Eric Lee (right)