Installing Electronic Circuits of Dramatically Increasing Size into Compact Devices - Murata's MLCC for 5G Smartphones (Part 1 of 2)

As the Applications for 5G Expand Due to Its Increased Performance, the Circuits Inside Devices Are Dramatically Growing in Size

Commercial service for the 5th generation mobile communication (5G) has finally started. The performance of smartphones has been greatly enhanced with ultra-high speed, large capacity, ultra-low latency, and multiple simultaneous connections, and new applications are expected to grow, such as rapid downloading of 4K-quality video data, communication using virtual reality (VR), and linkage between computers and machines in remote locations. Moreover, there are high expectations for the use of 5G as an element in the communication infrastructure for realizing a prosperous and low-waste society by encouraging the use of data in factories, medical facilities, and social infrastructure.

5G-enabled smartphones will likely incorporate electronic circuits with more diverse and complex structures than ever before. In terms of cellular communication functions alone, they need to support the Sub-6 band (3.7 GHz and 4.5 GHz), the 28 GHz band (millimeter wave band), and the existing 4G band. In addition, circuits are needed to utilize Bluetooth®, Wi-Fi, and Near Field Communication (NFC) for data communication with peripheral devices, and GPS to detect location. Assuming that 5G smartphones will use these diverse and high-precision wireless communication functions, these smartphones will be equipped with high-performance cameras and displays, as well as sensors and signal processing circuits necessary to utilize new applications such as VR and AR (Figure 1). Consequently, this will dramatically increase the size of the electronic circuitry inside the device.

Figure 1. Examples of functions to be incorporated in 5G-enabled smartphones

Miniaturization of the Electronic Components Making up Internal Circuits Is Essential for Developing Attractive Devices

However, if the device itself is made larger as the electronic circuits become larger, the product value can be undermined. Over the past few years, smartphones have been becoming larger in size in order to increase the display size and battery capacity. However, we have already reached the limit of the size that can be easily carried around, and there are even calls for smaller chassis designs. In order to create value-added and user-friendly devices, ultra-high-density mounting technology is required that can incorporate large-scale electronic circuits while maintaining the size of the device.

Of the elements in an electronic circuit, semiconductors can support ultra-high densities using the same methods as before by increasing the integration of elements on a chip and by using software for functions, even as devices become more advanced and multifunctional. However, for multilayer ceramic capacitors (MLCCs), which are essential electronic components for ensuring stable operation of electronic circuits according to technical specifications, it is essential to reduce the size of the element itself.

Approximately 800 to 1000 MLCCs are used in each smartphone. Moreover, as the number of functions installed in a device increases, the number of installed MLCCs also increase proportionally. The key to creating a high-performance, multifunctional, and user-friendly 5G-enabled smartphone of the right size will depend on the miniaturization of MLCCs.

Development of 0201M/0.1 μF and 0402M/1 μF in Anticipation of Installation in 5G-enabled Smartphones

Murata Manufacturing Co., Ltd. (“Murata” below) has developed the GRM011R60J104M, an MLCC with the world’s largest* capacitance at 0.1 μF in the world’s smallest* 0201M (0.25 x 0.125 mm) size. Compared to our previous 0402M size (0.4 x 0.2 mm) with the same capacitance, the new product occupies only 1/2 the mounting area and 1/5 the volume (Figure 2).

*Murata findings as of September 29, 2020.

Figure 2. Appearance of MLCCs of size 0402M and 0201M

To date, Murata has been leading the world in miniaturization of MLCCs and has been contributing to the miniaturization of electronic devices. The 3216M (3.2 x 1.6 mm) size MLCC introduced in the 1970s was used to develop compact and thin portable radios, and the 2012M (2.0 x 1.2 mm) and 1608M (1.6 x 0.8 mm) sizes were introduced in the 1980s and 1990s to make AV equipment and PCs smaller and more portable. In the 2000s, the 1005M (1.0 x 0.5 mm) and 0603M (0.6 x 0.3 mm) sizes helped to make cell phones (feature phones) more multifunctional. Because of this record of accomplishment of proactive efforts to reduce the size of MLCCs, we have captured more than 50% of the market share of 0402M size MLCCs, which are widely used in smartphones.

At Fukui Murata Manufacturing, a mass-production system is already in place for the 0201M size, 0.1 μF MLCC developed for use in 5G-enabled smartphones. Going forward, Murata will continue to lead the way in miniaturization of MLCCs and to support the miniaturization of electronic devices as well as greater multifunctionality and higher performance.

Reducing the Size of the Numerous MLCCs in Devices to 1/5

A single 5G-enabled smartphone contains a large number of MLCCs. This component has a significant impact on the miniaturization of the device. The miniaturization of MLCCs is essential for making devices multifunctional while maintaining a usable size. Over the past nearly half century, Murata has been a leader in the miniaturization of MLCCs. And building on our past achievements, we have developed a new generation of compact MLCCs that are designed for installation in 5G-enabled smartphones. We asked the product planners of MLCCs for 5G-enabled smartphones and the engineers who have been working on the development of smaller and higher capacitance MLCCs about the details of the MLCCs they have developed and their impact on device development.

From left, Marketing Manager Tsuruzono, Product Development Manager Wakashima

With More Than 1,000 MLCCs Used per Device, Their Miniaturization Has a Significant Impact

--For what applications and how many MLCCs are used in 5G-enabled smartphones?

Today's smartphones are rapidly becoming more and more multifunctional. In addition to the electronic circuits for wireless communication, smartphones include many other electronic circuits, such as displays, cameras, and processors for executing a wide range of processes. To ensure stable operation of these electronic circuits, many capacitors are used to supply power and eliminate noise.

Smartphones need to pack a lot of electronic functions into a small chassis, and the capacitors need to be as small as possible. For this reason, most of the capacitors used in smartphones are MLCCs, which excel in miniaturization, and there are now more than 1,000 MLCCs in each high-end, state-of-the-art smartphone.

--There are so many MLCCs being used, it may be the most widely used component in smartphones. So, what characteristics of MLCCs are required for 5G-enabled smartphones?

MLCCs with smaller size and larger capacitance are needed. 5G-enabled devices are expected to have more functions installed in a single unit than 4G devices, and as a result, the electronic circuits installed in the chassis are expected to be larger. This will further increase the number and total capacitance of MLCCs in the device (Figure 3).

Figure 3. Market forecast for consumer MLCCs and MLCC capacitance in smartphones

For example, 5G devices will need to support more frequency bands than 4G devices. In order to provide high-quality communications while using various frequency bands within a single device, the noise mixed from unused frequency bands must be removed by filtering out the frequency bands that are not used. In these devices, many MLCCs are used that have small capacitance but low capacitance variation.

However, it is becoming increasingly difficult to even maintain the current size of the smartphone chassis, and there are growing needs to make it smaller. To meet these needs, further miniaturization of MLCCs is essential.

Battery capacities are also increasing due to the added functionality of devices. In order to charge large-capacity batteries stably and quickly, higher capacitance and higher quality MLCCs are needed. Furthermore, demand for higher capacitance MLCCs remains strong because, in certain electronic circuits, the number of MLCCs can be reduced by using higher capacitance products.

1/2 the Mounting Area and 1/5 the Volume Compared to the Same Capacitance Product

--What features did Murata develop in its MLCCs for 5G-enabled smartphones in order to increase the scale of circuits and maintain or reduce the size of devices?

By introducing a new generation of manufacturing technology, we have developed the world's largest capacitance MLCC of 0.1 μF in the 0201M size, which is the smallest MLCC size currently available. MLCCs in the 0201M size have been available in the past, but their small capacitance of 0.01 μF limited their use in smartphones. Furthermore, we have achieved a product with a rated voltage of 6.3 V and a capacitance tolerance of ±20%, which is suitable for smartphones.

Before, MLCCs of the same capacitance, which have been used in many smartphones, were 0402M in size. This has been reduced to 0201M size, which uses only 1/2 the mounting area and 1/5 the volume, making it significantly smaller. In addition, we have also developed a 0402M size 1.0 μF MLCC using the new manufacturing technology that we adopted for this MLCC. This one also has the world's largest capacitance for MLCCs of the same size.

--What impact will the MLCCs that you developed have on the development of 5G-enabled smartphones?

I mentioned earlier that more than 1,000 MLCCs are used in the most advanced smartphones. More than 200 of them correspond to the 0.1 μF and 1.0 μF products that we developed this time. Since each of these MLCCs has been dramatically reduced in size, this will have a tremendous impact on the miniaturization of devices.

The MLCCs that we have developed will enable development of devices with higher added value by allocating the space saved from the reduced substrate area to add further functions and higher battery capacity. In addition, wearable devices and IoT devices have higher added value because of their small size. Smaller wearable devices are less uncomfortable to wear, which expands their usage scenarios. Smaller IoT devices are also more likely to collect valuable data because the requirements for installation locations are relaxed. Therefore, we believe that the newly developed MLCCs will be widely used in these types of applications.

--You mentioned that the rated voltage is 6.3 V, but what does that mean?

The battery in a smartphone provides power at 3 V to 4 V. Therefore, an MLCC rated at 6.3 V is an easy specification to use in electronic circuits that are directly driven by that battery. In smartphones, some components such as processors are driven at about 1 V, where MLCCs rated at 4 V are often used. However, some customers also use MLCCs rated at 6.3 V for circuits around the processor to reduce the complexity of parts management. For this reason, it is important to have the smallest size product available with a 6.3 V rating.

Ready for Mass Production

--When and where will you start mass production of MLCCs developed for 5G?

A mass production system is already in place, and mass production is scheduled to begin at Fukui Murata Manufacturing in 2020. Within the Murata Group, Fukui Murata Manufacturing is our flagship plant that leads the way in developing miniaturization and larger capacitances for MLCCs in terms of both technological development and mass production (Figure 4). It is responsible for being the first to adopt new technologies for cutting-edge miniaturization and larger capacitances and for transferring the technologies to other production bases when the technologies mature.

Figure 4. Murata's main MLCC production sites

For the widespread use of compact MLCCs, customer companies will need state-of-the-art mounting machines (mounters) that can handle the mounting of small electronic components. The 0201M size is extremely small, but we started mass production in April 2014. At that time, we completed the development of the corresponding mounter with the mounter manufacturer, and our customers were ready to use this size MLCC. With the production of 5G-enabled smartphones in full swing, demand for 0201M size is rapidly growing, and we are confident that demand will increase in the future.

The information presented in this article was current as of the date of publication. Please note that it may differ from the latest information.

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