A Team of Crystal Experts Joined Murata Generating Synergy with Murata’s Ceramic Technology to Create Further Innovative Products
A Discussion Meeting on Timing Devices
Takuya Kohno、Kazunori Takami、Hiroaki Kaida、Toshihiro Mizuno
Isamu Horii、Susumu Okazaki、Kazumi Yoshida
A reference signal is necessary for all electronic circuits connected in a network to operate in synchronization. Just like an orchestra conductor, the timing device gives instructions regularly at fixed intervals. A new group of crystal experts achieved a technical fusion with Murata’s traditional ceramic technology. The new engineers and Murata technicians began to work as a team, generating a new trend. The new timing device was developed through company-wide teamwork at Murata. It is an innovative hidden driving force for the teamwork of electronic circuits.
From Ceramics to Crystal: Ore Production Generates a Foundation for New Technology
Mizuno Timing devices play a critical role in electronics. Murata had offered the CERALOCK series of ceramic resonators, and last year, the company acquired Tokyo Denpa (TEW) as a subsidiary. TEW has excellent products and technology in the area of crystal devices. Already we have upgraded the product lineup, and now we are working to strengthen the development, production, and sales of crystal devices. Murata’s timing device business is now undergoing a major transformation. Here we have persons from various departments―including not only crystal production, but also development, production, and planning and sales promotion. We would like to discuss how Murata will develop its timing device business further in the future. As an icebreaker, Yoshida-san, could you explain your work on the ore used for crystal devices?
Crystal Ore for Timing Devices Taken Out from an Autoclave after Some 80 Days of Growth
Yoshida We at the TEW plant in Gunma produce artificial crystal. Imported natural crystal is put into a pressure vessel with a length of 15 m and an inner diameter of 60 cm. An alkaline solution is added before leaving the vessel under a pressure of approximately 1,500 atm. Crystals grow by 0.5 mm every day. By maintaining the pressure and constantly passing a current through the solution for three months, we can make some two tons of artificial crystal. Unlike other engineering processes employed at Murata, it’s a very slow process. In the worst case scenario, we can face a total loss. Accelerating daily growth does reduce cost, but it gives rise to problems with denseness and other qualities of crystals. Instead of using the same method all the time, we are now making attempts to change ore quality depending on the resonator performance required. Fortunately our customers give a high evaluation of our ore quality. As crystal continues to grow day after day, its structure can suffer misalignment. By that I mean crystal defects, which are microscopic and invisible to the eye. They can only be found by closely examining cross-sections of the grown crystal. Crystal structure is said to be “inherited.” That’s why there is a special technology for selecting the “seeds” used for crystal growth. A further highlight is a method of growth that prevents defects from increasing. During growth, the crystal material is heated to around 400°C, but it goes supercritical at 230 to 280°C. We have seen that we cannot get good crystals if growth continues in that phase. The knowhow we have developed over many years has given us successful methods of making crystals grow and controlling their growth.
While Pursuing Downsizing, Murata Is Surmounting the Challenges of Mass-Production
Mizuno Yoshida-san is right. TEW crystal has a reputation for high purity and quality. This is one of our unique strengths. Good command of crystal technology means a high standard of perfection for our products. We have a desire to further explore this advantage we have gained through our alliance with TEW. The next process using this ore is the production of blanks (piezoelectric crystal pieces).
Kohno Quartz crystals have various oscillation modes. So, different crystal blanks are used depending on the frequency or electrical performance of the quartz crystal. TEW was the first in the industry to mass-produce compact quartz crystals in 2016 (2.0 x 1.6 mm) and 1612 (1.6 x 1.2 mm) sizes. Murata is taking over the company’s knowledge and knowhow and improving them further in terms of characteristics and productivity. As a matter of course, the quality of crystal ore is a critical factor in resonator quality. Murata has an advantage here since it can supply itself with superior ore. But besides the quality of ore, the angle at which the ore is cut, and resonator shape design are also important. If these go wrong, we will have poor or unstable temperature characteristics of oscillating frequency. The more compact the resonator, the more difficult it is to design. So it is critical to find an appropriate design, set the best conditions for the manufacturing process, and control the process successfully. Murata has an advanced technology for simulating device designs; we have a foundation for designing resonators logically. Simulation of quartz crystals faces a lot of difficult problems. But we have been improving simulation techniques and developing a simulation-based design method, making it possible to design quartz crystals quickly and properly. These efforts help deliver stable performance and quality. We have yet to figure out a lot of things when it comes to producing quartz crystals. For example, by the time they enter mass production, they can sometimes show characteristics different from those they had initially. Challenges include further downsizing and increasing resonator performance and production precision.
“Scientific control based on simulation technology helps produce outstanding products.”
Takuya Kohno Senior Engineer
Product Development Sec.2, Product Development Dept., Timing Device Division
Toyama Murata Manufacturing Co., Ltd.
Since joining TEW in 1994, Kohno has worked on the design and development of various quartz crystals including types in 2016 and 1612 sizes. His favorite pastimes are climbing mountains and reading books.
Applying Superior Product Packaging Technology to Create an Innovative Quartz Crystal
Mizuno This is the first time we work on crystal, but if Murata’s traditional production technology and production management fit well, I believe we can open up a completely new area of engineering. Murata is strong in product packaging, and it has used the technology successfully in the CERALOCK series.
Okazaki That’s right. Packaging is one of the best technologies we developed for the CERALOCK series. The HCR is an application of that technology to quartz crystals. In 2009, it was the first quartz crystal to come from Murata. To generate advantages in performance, quality, and cost, we chose to use the Cap Chip structure, which had been successful with CERALOCK resonators. But for sealing, this first product employed resin. This made it all the more cost-effective. Usually quartz crystals are airtight. For crystal manufacturers, using a resin-based and non-airtight structure was simply breaking the rules. Of course we were also very skeptical about it. So we made various checks on characteristics and quality before completing the design. Today the HCR is the core product in the Murata quartz crystal lineup and enjoys increasing sales. I would say only a rule breaker like Murata could have made it. Since the launch of the HCR, all products, be they airtight or not, have been developed on the basis of the Cap Chip structure. In product development, we always face serious challenges in material technology for items such as sealants and package materials. At such times, we are encouraged and relieved by the wealth of expertise and knowhow Murata has accumulated on various materials. As in the product development of the CERALOCK, we work closely with material engineers.
“The HCR featuring the Cap Chip structure was an innovative milestone that applied Murata packaging technology to crystal.”
Toshihiro Mizuno General Manager
Planning & Sales Promotion Dept., Timing Device Division
Murata Manufacturing Co., Ltd.
Mizuno entered Murata Manufacturing in 1989. After working on the development of sensors and product engineering for piezoelectric components, he was transferred to Singapore and Shanghai. Back in Japan, he has been responsible for the planning of actuators and timing devices. Mizuno loves playing golf and traveling.
A Well-Established Production System Is the Key to the Unique Combination of Quality and Mass-Production
Mizuno I assume you have overcome various challenges in the area of equipment and production.
Takami The so-called “Golden Triangle” of manufacturing consists of three factors: product design, materials, and production equipment, which includes process designs. To achieve the best combination of these three factors, we work on the production line layout in consideration of the processes and study possible operation designs for easy work. These aspects directly affect our income, and so the production system must be developed while taking the results of cost management and cost simulations into account. Product quality and the ability to mass-produce trade off against each other, but we must achieve mass-production while ensuring high product quality standards. The airtight sealing process is of course difficult to perform, but the preceding process also has various quality determinants. For example, characteristics vary by simply changing processing circumstances. In a sense that is what makes the job rewarding. We hope such difficulties reveal the essence of the processes and/or help us analyze some of the implicit knowledge we have so far gained from experience. What annoys us the most in developing a new product is that we are forced to fight against requirements regarding quality, costs, and time. Our compact products that have entered the mass-production phase are generating new demand by finding use in smartphones and other mobile phones. If a product we have developed achieves wide acceptance in the market, we even begin to enjoy following a tight schedule.
“The three elements of manufacturing form the so-called ‘Golden Triangle.’ Products that have reached the mass-production phase create new demand.”
Kazunori Takami Senior Manager
Production Engineering Section 1, Production Engineering Dept.
Toyama Murata Manufacturing Co., Ltd.
After joining Toyama Murata Manufacturing in 1987, Takami engaged in developing production technologies and mounting processes for resonators, dielectric filters, and sensors. He has been responsible for production technology for timing devices since 2012. His favorite pastime is visiting spiritual power spots.
The Pursuit of Originality: Adapting CERALOCK Technology to Crystal Products
Mizuno The section for developing manufacturing equipment and processes is strongly connected with the production floor. They work with the manufacturing plant to develop operator-friendly production lines and work out measures to enhance maintenance power. With the Cap Chip structure, the most important process is that of packaging a plate in combination with a metal cap. We had a hard time commercializing the product. Traditional manufacturers of quartz crystals commonly used production equipment and materials already available in the market. By contrast, we have been original on all counts, from materials to the package structure. Accordingly, the production process has also been developed on our own. To that end, a lot of people are gathered from various departments. Teamwork is the core of all that. What then about technical services and circuit applications?
Horii A timing device is used to synchronize an IC with various circuits. Since ICs from different manufacturers have different characteristics, we check to see how they can be synchronized best. The hardest part arose from the fact that quartz crystals require much higher measurement accuracy than their ceramic counterparts. We must be careful about various aspects. We have to make more accurate measurements to report to the customer, but in so doing we cannot damage the substrate borrowed from the customer. What’s more, we cannot borrow substrates from all customers. If that’s the case with a customer, we might visit them directly for evaluation. This holds true not just for domestic clients; we are also beginning to go overseas to provide such service. Murata has a high share of the market for ceramic resonators, but we are still a newcomer in the area of crystal devices, so we are striving to increase customer satisfaction by offering services tailored to individual customers.
“Murata is the only supplier that offers a full line of timing solutions including ceramic, crystal and new technologies.”
Isamu Horii Manager
Product Engineering Section 5, Planning and Sales Promotion Dept., Timing Device Division
Toyama Murata Manufacturing Co., Ltd.
Since entering Toyama Murata Manufacturing in 1990, Horii has always engaged in product engineering. His hobby is marathon running. After completing a 100-km race in 2014, Horii recorded three hours and 40 minutes in the 2015 Tokyo Marathon, smashing his personal best time.
Rule-Breaking Innovation, Power from Teamwork
Kaida Murata developed the CERALOCK ceramic resonator early on and has been producing it since. In the market for ceramic resonators, we have taken great strides and still keep a high market share. Ease of oscillation is a performance characteristic of ceramic resonators. Murata has introduced various technical ideas in the technology to increase performance and reduce size and cost further. That’s why Murata ceramic resonators were widely accepted in the market, but had a drawback: their accuracy was difficult to improve. Most quartz crystals have a frequency accuracy of 20 ppm, whereas ceramic solutions have approximately 10,000 ppm. To meet customer requests for higher accuracy, we implemented a range of measures to eliminate this disadvantage. In doing so we successfully developed a product with 3,000 ppm and, by the beginning of 2000, we even aimed to achieve 500 ppm. At that time some of us already suggested using crystal, but we made it our policy to pursue our ceramic technology to the end. Predictably enough, it was extremely difficult to develop a 500 ppm CERALOCK. Nevertheless we managed to commercialize one. This was the fruit of the teamwork that strongly united the relevant departments. At the same time, it also made us all deeply understand how the ceramic technology is limited in terms of accuracy. It would eventually lead to our decision to use crystal. In retrospect, it would seem that the sense of urgency and the cooperative attitude generated by this recognition combined to drive everyone at Murata toward the development of a quartz crystal. When it comes to improving accuracy, Murata was at the end of the rope. We thought we had no choice but to gamble on it. The people from TEW were also really cooperative. In this way, we finally completed the HCR quartz crystal. Our competitors in the crystal industry seem to see the HCR as a threat. In addition to the technical idea and foundation in the form of resin sealed packaging, I believe the key to success also lies in our culture in which outstanding teamwork is simply achieved spontaneously. We might face even greater difficulty as we go on to carry out second and third projects. But we will overcome all challenges with our strong teamwork.
Murata decided to switch to crystal technology to achieve frequency accuracy of a few ppm. I feel we resolved the challenge with our teamwork.”
Hiroaki Kaida Senior Manager
Product Development Dept. Timing Device Division
Murata Manufacturing Co., Ltd.
Since joining Murata Manufacturing in 1987, Kaida has almost always worked on the development of applied piezoelectric products with a focus on piezoelectric ceramic resonators and crystal devices. His favorite pastime is doing Tai Chi.
A Company-Wide Initiative with All Members Sharing Issues to Achieve a “Vertical Startup”
Mizuno First we introduced a resin sealed, that is non-airtight, HCR, followed by an airtight type. Was all this made possible by teamwork?
Okazaki In the case of the airtight type, we were able to launch the product more quickly than ever. People from the production department were involved right from the development phase. We were all ready to share problems with production equipment right from the design phase; from the beginning we worked together to resolve them. I suppose that was the key to success. It made for a so-called “vertical startup,” that is full production right from the start. It’s a race against time when we are trying to establish a new technology like this. The thing is, as time goes by quickly, how can you meet the delivery deadline without missing the timing? In a situation like that, the production and development departments at both TEW and Murata were able to work while sharing the same commitment. I believe that will be a great asset for us. In the development phase, the merger had yet to take place and so both companies were still business partners. That’s why each side somehow hesitated to ask the other what kind of technology and knowledge it had. But as they developed the same product together, they came to share the same challenges, resolve the same problems, and laugh together. Since we shared the same hardships, I feel that our relationship was strengthened gradually. That is the emotional, not the technical side, but it’s very important. If I may complain here, I would say Murata has yet to make full use of the ore TEW produces. We won’t be able to develop quartz crystals that give us an advantage over the competition unless we upgrade our ore processing technology and design ability. These are challenges we will need to face from this point on.
“Murata demonstrated its full power in the company-wide initiative of the vertical production startup for the airtight quartz crystal”
Susumu Okazaki Senior Manager
Product Development Sec.2, Product Development Dept., Timing Device Division
Toyama Murata Manufacturing Co., Ltd.
After entering Toyama Murata in 1999, Okazaki learned how to engineer piezoelectric products in design and production engineering departments. For the past two years, he has been responsible for the development of quartz crystals. Okazaki loves reading books and playing golf. He is now struggling to acquire a correct swing posture.
Turning Timing Devices into a Key Business by Going beyond the Downsizing Trend
Mizuno The near-term goal is to turn our timing devices into one of our key businesses by 2020. Do individual sections have specific ideas of how to achieve that?
Yoshida Looking from the perspective of ore production, I wonder how far devices will be downsized. Perhaps down to less than 1008 (1.0 x 0.8 mm) size. And then we will be required to achieve even higher ore quality. How we cut crystal materials out of the ore will count. Going forward we will need not only to improve machining technology, but also to develop etching technology. We will be required to control the process to achieve zero defects and thereby stabilize Q factor. At the same time we will need to eliminate all foreign particles. Now we cut different materials out of the same ore. But in the future, we may need to produce different types of ore depending on the applications, say by using different solutions or by using different mixes. In fact we are beginning to do trials to accomplish that. We want to achieve results as soon as possible so we can decide which way to proceed.
Microfabrication of Crystal Is the Next Challenge Murata Will Face in the Crystal Industry
Kohno Crystal blank shape will be the key to ensuring excellent characteristics as devices are downsized even further. The question is, how accurately can we achieve optimal shape? To that end, crystal micro fabricating technology will be increasingly important. This technology involves the chemical processing of crystal, and so, if your crystal has defects, it could eventually have cavities at such locations. If that is the case, the quartz crystal can’t have stable characteristics. That’s why I believe Murata’s ability to control crystal ore production for quality will give us a certain advantage in the future development of microfabrication technology.
Optimal Solutions that Meet Customer Requests
Mizuno To make full use of crystal, we need to offer customers timing device concepts while eyeing other technologies. We hope we will be able to offer all possible solutions―ceramics and crystal, or other highly potential solutions and technologies―to meet the needs of all customers. The aim is to win in all areas of timing devices.
Kaida The mainstream technology (material) for low accuracy timing devices is ceramic technology (ceramics). The counterpart for high accuracy products is crystal technology (crystal). I suppose this market configuration will remain firm for the time being. In addition to ceramics and crystal, we are studying other solutions as well, and we will continue such investigation and research. Crystal technology features outstanding temperature characteristics and high Q factor, and shows very small variations in these parameters. So I don’t expect any other solutions to be improved in the near future to the point where they can compare with crystal products in the high accuracy category. Given this situation, Murata will likely be accepted more widely in the market if we can make better use of our ability to produce crystal ore. Then we will be able to help improve the communication quality of next-generation networks. We will also be able to create products for new markets, for example those for healthcare and energy, which will open up in the future.
An Attractive Product with Zero Particles Circuit Integration Has Potential
Horii Crystal devices have long been accompanied by concerns about failures caused by foreign particles. I hear it’s a chronic problem. By contrast, Murata’s resin sealed HCR version is completely free of particles. From the beginning, the production line is designed to monitor and eliminate particles. We also use a unique technology that takes advantage of the characteristic product structure to detect particles. Thanks to these measures, we receive no customer complaints about particles. Since we have produced more than a billion units over the past few years, the failure ratio is less than 1 ppb, that is, almost null. This is very attractive to customers.
Kaida Actually I think that, in crystal products, we have yet to make full use of the technology developed for ceramics. With ceramics, we have taken advantage of their high workability to exploit varying oscillation modes for different products. The use of microfabrication technology for crystal products will make it possible to process the material into a greater variety of shapes. I expect this will allow us to apply the knowledge of oscillation modes we have accumulated for ceramic resonators. We are eagerly awaiting that day, and we are developing various specific ideas in order to do so. If measures regarding oscillation modes allow us to make the quartz crystal even smaller, we might be able to integrate it in an IC. On the other hand, if we use a unique substrate from Murata in the package, we might be able to put a different functional element in it. In other words, we are eyeing the possibility of moving with and/or promoting a future integration trend, while at the same time studying various possible measures.
Integration of a New Organization Led to Team Restructuring Organizational Fusion Helps Create New Technologies
Mizuno Before launching a new product, we need not only research and development, but also all kinds of technologies, including technologies for material development, processes, circuit design, production, analysis, and evaluation. Murata has developed these technologies and knowhow independently, opening up new diverse dimensions of electronic components. In the area of timing devices, the TEW crystal device team joined the Murata Group. This led to a restructuring of the team that generated new teamwork. Both companies with different cultures were integrated to do business together. Didn’t that cause any problems?
Kohno At TEW, I used to only design quartz crystals. Business in this field is extremely specialized, requires precision, and delves into the smallest details, and that’s why TEW engineers sometimes get stuck. By contrast Murata is an all-rounder, a “can do anything” company. At first, I was impressed that Murata was able to do just anything. Now I’m pretty happy because I’m allowed to do various things. But again I feel more pressure.
The Restructured Team with New Teamwork Will Serve in Developing New Engineering-Just like a Timing Device
Kazumi Yoshida Plant Manager
Tokyo Denpa Company, Ltd.
Since joining TEW in 1977, Yoshida has been engaged in growing monocrystals of substances such as quartz and zinc oxide. He loves clay shooting, rifle shooting, and hunting large animals.
Engineering with Teamwork Continues to Evolve Further
Yoshida I’m looking forward to seeing how things will develop following the introduction of Murata technologies in our crystal ore business. We have so far relied on experience. But scientific experimentation and research sometimes makes us convinced of our traditional practice through objective data. By introducing Murata technologies, I believe we will advance even further.
Kaida Ore and blank technologies involve implicit knowledge. Its principles must be learned thoroughly before it can be subjected to scientific analysis. That’s exactly where Murata’s knowhow comes in. And you can put your job aside and broaden your perspective to think about issues that you expect to arise in five or ten years’ time. You are encouraged to do so at Murata. When you begin, it’s tough in a way, but it gets more fun little by little. Murata continues this initiative to prevent employee awareness from becoming outdated or fixed. I would say this kind of company-wide initiative forms the basis of our teamwork.
Mizuno As is often said, we must look at both “business management of today” and “business management of tomorrow.” We tend to be preoccupied with what we do today and forget about tomorrow. We might no longer be at the company in 10 or 20 years, so we must foster younger people to consider both aspects. That’s another element of our teamwork. Murata certainly has various systems, which ensure proper operation management, for example. But when it comes to crystal devices, TEW is more advanced in some respects. We want to visualize each of these advantages of TEW. In this way, the addition of a new team to Murata has opened up a new dimension in our teamwork. Just like timing devices, we hope we can serve as the core in ensuring the cooperation of all people.
Grown quartz crystal used to produce crystal devices. Pressurized in a sealed vessel with a length of 15 m and an inner diameter of 0.6 m, quartz crystals grow by 0.5 mm every day.
A small piece of natural crystal or high purity artificial crystal material from which an ore of the same material is to be grown.
A piece of piezoelectric material cut in a specified size and shape and at a specified angle from a crystal (ore) in reference to the crystal axes.
*4 Frequency accuracy:
An important property of a timing device. Crystal has an extremely high frequency accuracy (a few ppm).
*5 Q factor:
A parameter that indicates the duration of underdamped oscillation. Higher Q factor shows that the oscillation is more resistant to damping.
*6 Resonator and oscillator:
A resonator is a component that seals an oscillating element with electrodes in a package. An oscillator is a component that integrates a resonator and an oscillating circuit in a package. The difference is that an oscillator has an oscillating circuit in it.
ppm is an initialism for “parts per million” and denotes a value of 1/1,000,000. ppb stands for “parts per billion” and denotes a value of 1/1,000,000,000.