Excerpt from: Semiconductor Industry Observation
Over the years, the semiconductor industry has witnessed a range of package innovations, such as system-in-package, semiconductor embedded in substrates, and fan-out wafer-level packaging.
Currently, two interesting package innovations are being applied during the miniaturization of microchips and electronics. One is a new concept that combines two tried and tested technologies; the other is an old technology that was decades old and is being used in new ways.
Sealed packaging and sealing processes that isolate electronics from dust, moisture, air, and even atmospheric pressure have been around for 75 years, longer than transistors and integrated circuits. The hermetic encapsulation and sealing process creates a hard-to-penetrate protective layer around the electronics that keeps air and water vapor away from the electronics, making it airtight and impervious to water, protecting the electronics from corrosion and other environmental damage.
New developments in hermetic packaging and sealing processes have made possible faster, lighter, smaller electronic products.
Any technology that helps add more components without sacrificing functionality is popular with handset manufacturers. Another leading edge technology that pursues miniaturization is a substrate-like printed circuit board (SLP), which represents the intersection of a flexible substrate and a rigid board.
SLP is now only available on smartphones, but it may be used in IoT devices and ultimately in AI applications, AR/VR devices, and automobiles. One of its biggest advantages is that there is no need to choose between PCB or substrate.
According to Yole Développement, SLP is used in the iPhone 8 and iPhone X, and Yole describes the technology as "the conflict between the two worlds of PCB and substrate." According to Yole, SLP can be considered as an alternative to modified semi-additive processes (mSAP).
Yole's technology and market analyst Emilie Jolivet writes: "Advanced substrates must meet the needs of both miniaturization and functional roadmaps. In the field of high-end smartphones, the transition from subtraction to mSAP, from PCB to SLP is underway. This is driven by Apple and its iPhone 8/iPhone x. Other high-end smartphone vendors such as Samsung and Huawei are expected to join in the near future."
SLP will have to compete with other technologies, namely package substrate vs. substrateless fan-out package, and through-silicon via package (TSV) vs TSV-less package
Yole predicts that the SLP market will grow from $1.9 billion in 2016 to $2.24 billion in 2023.
Yole's Vivienne Hsu said: "The 28 selected PCB/substrate manufacturers are considered to have mSAP technology, some of which can produce SLP. Under the drive of high-end smartphone demand, some companies seem to have high capital expenditures. At the same time, the revenue of some large companies' PCB/substrate business is stable."
Seung Wook Yoon, the parent company of STATS ChipPAC and director of technology strategy at JCSET Group, described SLP as "the changer of the industry game rules."
SLP may mean that outsourced semiconductor package testing (OSAT) customers do not have to choose between their PCB and substrate. Yoon expects Samsung to follow Apple's approach.
Yoon said that fan-out wafer-level packaging is for high-end application processors, and they will be used in high-end products, such as the flagship of mobile phone manufacturers. SLP is suitable for mobile phone motherboards, which can reduce the space required for such components. He pointed out that ball grid arrays or flip chip packages are more commonly used in fine pitch slots in cell phones. Wafer-level packaging provides finer pitch.
Yoon compares the SLP to an onboard package.
According to Yole, PCBs are evolving and they offer integration in addition to interconnects. Yoon responded to this view. He said: "Mainly for integration."
While the first notable application for SLP is in mobile phones, this advanced semiconductor package can also find applications in 5G wireless communications, AI, VR/AR, automotive electronics and IoT devices.
Yoon pointed out that system-level packaging technology and modules are another advanced space-saving innovation in advanced packaging, but at a higher cost.
In addition to mobile phones, Yoon believes that SLP may also be used for IoT devices. Cost reduction and downsizing are still top priorities.
Sealed package and sealed
At the same time, sealed packages and seals are ubiquitous. Widely used in automotive electronics, aerospace systems, optical communication components, fiber optic data communication systems, sensor manufacturing and other industrial fields. Automotive airbag igniters are an example of a sealed package.
Robert Hettler, director of optoelectronics research and development at SCHOTT Electronic Packaging (a subsidiary of SCHOTT North America and Schott, Germany) said: “It is difficult to determine an overall trend. There are many trends in different markets and applications.”
Higher precision is one of the trends. The world's growing desire for data and faster transmission speeds has increased the demand for high-performance chips.
Hettler said: "The faster chips require a reliable, high-performance sealed package for faster data transfer speeds. Without a new generation of high-performance, high-precision hermetic packages, the so-called "last" connected to the customer Miles – a fiber-optic transmission line that covers the home – is impossible. SCHOTT recently introduced a 50G sealed transistor package that paves the way for the much-needed bandwidth increase in datacom networks. 50G sealed transistor housing technology (transistor) Outline, TO) also enables faster data transfer to wireless base stations, providing a technology that can be used to deploy 5G cellular networks, an improvement that will be exponentially faster than the speed offered by current 4G infrastructure."
Hettler also mentions a variety of materials for hermetic encapsulation and sealing.
Hettler said: "At the material level, the demand for non-magnetic materials such as titanium and tantalum is increasing. These materials are very attractive in many high-reliability applications. If a non-magnetic and lightweight housing is required, then glass titanium The compounds are particularly suitable for aerospace, oil and gas, and medical technology. In addition, nickel-copper alloys are highly suitable for chemically corrosive environments due to their acid and alkali resistance. In the field of medical electronics, the trend of implantable devices has also led to titanium and The demand for biocompatible materials has increased. Here, the development of highly reliable and increasingly miniaturized sealed packages is very important. The development of glass-aluminum sealing technology has enabled the manufacture of sealed seals for aluminum today. This material is ideal for applications that require lightweight materials or aluminum housings, such as supercapacitors, double-layer capacitors, and lithium-ion batteries. The newly developed aluminum cover system uses a sealed glass-aluminum seal feedthrough. Capacitors and batteries that support higher performance and longer lasting performance."
The miniaturization of modern electronic products is a priority, and sealed packaging and sealing can meet this need.
Hettler said: "Glass-metal sealing and ceramic-metal sealing miniaturization is a compelling key issue. More and more application requirements, especially the need for smaller and smaller form factor components, make small Turning into a key theme for product innovation. A particularly relevant example can be found in the field of fiber optics. The TO package for high-speed data transfer has been downsized for new cutting-edge applications: in the development of TO56 to TO38 packages and In the transition, the package size has been reduced by nearly 33%. In addition to the miniaturization of glass-to-metal sealing and ceramic-metal sealing, all-ceramic multilayer housings and substrates have received increasing attention. Trends to meet increasing complexity requirements while also providing excellent thermal management: The multi-layer design supports a miniature 3D interconnect solution that paves the way for high-density input/output capabilities in small hermetic packages. Can be used for feedthroughs and multilayer ceramic circuit board substrates. High thermal conductivity of high temperature co-fired ceramics and high temperature resistance above 300 °C make HTCC substrates Often suitable for high power applications. "
What is the current state of application for hermetic packaging and sealing?
“The most common uses for hermetic encapsulation and sealing are very different in many different areas,” Hettler said. Some of the most compelling applications include fiber optic and high-speed data transmission, automotive safety systems and other components, and pressure sensor feedthrough. And packaging applications. In the defense, aerospace and aerospace industries, sealed enclosures and connectors are often used to protect critical control and instrumentation electronics."
Microelectromechanical systems (MEMS) devices are an area that requires sealed encapsulation and sealing, not just an excellent technology in certain applications.
“MEMS is a sensitive and fragile component that is typically placed in harsh environments or placed where expensive or inconvenient to replace. Sealed packages and seals provide reliable protection and help extend these devices,” Hettler said. For example, Schotter HermeS glass wafer substrates feature sealed glass vias for miniaturization, high reliability and a powerful 3D wafer level chip scale package (WLCSP). Fine vias allow for electrical signals and power Reliable conduction into and out of MEMS devices. In recent years, the use of glass wafers in sealed packages has increased rapidly. The core reason is that glass has superior properties as a special packaging material, including its biocompatibility and excellent RF. Transparency and transparency to visible light make a wide range of optical applications possible. TGV technology enables long-term, reliable and extremely robust packaging for industrial sensors, RF MEMS and medical electronics."
To achieve ever-increasing miniaturization of microchips and electronics, we need a variety of new packaging technologies. Second, a proven method can also meet the needs, such as sealed packaging and sealing.