Site:                Murata Manufacturing Company
                      Technical Management Department
                      Nagaokakyo-shi, Kyoto 617-8555
                      

Date Visited:  1 June 1999

WTEC Attendees: L. Young (report co-author), L. Katehi (report co-author), D. Friday, J. Maurice

Hosts:           Hiroshi Kuronaka

BACKGROUND

Murata Manufacturing Company, Ltd., was founded by Akira Murata in 1944 and incorporated in 1950. Dr. Murata continues as honorary chairman of the company. Chairman of the Board is Osamu Murata, and President and CEO is Yasutaka Murata. Financial and other statistics (as of some time in the spring of 1998) were as follows: The parent company has some 50 subsidiary companies, half of them in Japan, the rest overseas, employing a total of nearly 24,000 employees, of whom the Japanese parent company alone employs about 4,500. Annual sales for the parent company alone (in dollar terms) were said to be $2.4 billion, but on a "consolidated basis" (which the panel understand to include all subsidiary operations) were $3.0 billion. R&D expenses are 6.6 percent of sales (both for the parent company alone and also on a "consolidated" basis). The company is capitalized at approximately $0.5 billion.

Murata's headquarters staff (Kyoto) is organized as follows:

Operating Divisions

  1. Research and Development Division
  2. Product Divisions (see also Note below)

Note: The Product Divisions include product strategy, development and design, and sales promotion in Japan, but each division has production facilities both in Japan and overseas, which enables the company to maintain close working relations with the customer.

Sales by world regions are as follows (rounded to the nearest integer): Japan 38%, Asia 25%, Europe 19%, and the United States 18%.

The panel visited the Yasu plant at company headquarters in Kyoto, where the number of employees is 1,850. The other major plant in Japan, not visited by the panel, is in Yokohama. Research is carried out both in Kyoto and in Yokohama. Kyoto seems to do more basic and design work, while Yokohama tests final products. For example, a large anechoic chamber at Yokohama is used for electromagnetic interference (EMI) suppression testing of systems containing Murata EMI suppression filters.

CURRENT PRODUCTS

The company holds a very strong position in the manufacture of ceramic materials and devices. Its success is based largely on the ability to manufacture ceramics and to design useful devices incorporating these materials better and cheaper than probably anyone else.

Murata's technology policy leads to integration of processes: Material, Processing, Design and Production. This approach is followed in all component and element design. About 10 billion capacitors are produced per month. Murata has extensive tools for design and analysis has developed its own manufacturing equipment. Material characterization is performed via resonator measurements using the HP equipment. This method will become an IC standard next year.

Sales by product area are as follows (rounded to the nearest integer): capacitors 40 percent, piezoelectrics 21 percent, circuits 12 percent, coils 5 percent, resistors 4 percent, other 18 percent.

Murata has a world dominant position in several products. Global market share in 1996 was as follows: ceramic filters (CERAFIL) and resonators (CERALOCK) 80 percent, chip monolithic ceramic capacitors 50 percent, microwave dielectric filters (GIGAFIL) 40 percent, PTC thermistors (POSISTOR), suppression filter (EMFIL) 35 percent.

Murata's main products include the following:

These products find industrial and consumer electronic applications in the following areas:

Industrial Electronic Equipment

Consumer Electronic Equipment

In addition there is a multiplicity of chip products, among them monolithic ceramic capacitors, ceramic trimmer capacitors, coils, thermistors, ceramic filters, SAW filters, discriminators, multilayer LC filters, multilayer delay lines, coaxial connectors, microwave filters, dielectric antennas, multilayer antennas.

Murata is a device and components company with a strong materials as well as design background and capability, which has now expanded into chip design. Its willingness to cooperate closely with the customer in integrating its devices into his equipment, and where possible in measuring customer equipment incorporating Murata's products, has contributed materially to its success.

ONGOING PRODUCT DEVELOPMENT

The presentations covered ceramic multi-layer devices, surface acoustic wave filters, and dielectric filters. Most of this work is based on the company's ceramic material formulations combining high dielectric constant with high Q (low dielectric loss), and good thermal stability in both dielectric constant and temperature coefficient of expansion. Murata ceramics are known as the best in the world. Dielectric constants range from 20 to 13,000. A value of 3000 is most popular. Ceramic dielectric constants are notoriously temperature sensitive, but one material changed only 10% from -45 (C to +85 (C.

Filters are developed using piezoelectric materials PZT and multi-layer technology for very low frequency applications from 400 kHz region up to 10 MHz. In addition ferrite materials are used to develop transformers and noise suppression filters. Pyroelectricity is material property explored by the company for sensor development. Furthermore semiconductor materials are used for the development of thermistors.

The kind of device used for filtering depends, among others, on frequency and power levels. Thus SAW filters are good at lower power levels and better at the lower frequencies. Piezoelectric filters have been used up to 450 kHz with an unloaded Q of 400 and only about 1/2 mm on the side. Ferrites are glossy ceramics attenuating because of their magnetic properties and are used for EMI suppression.

As with presentations at all sites, not all the work in Kyoto could be covered. For example, dielectric resonators and GaAs semiconductors, were mentioned only briefly.

The company has a good capability to design microwave combline and stepped-impedance filters and duplexers to specified performance. These dielectric filters are constructed in a neat miniaturized monoblock construction out of a block of high-dielectric-constant material (under the trade name GIGAFIL). The company has written its own proprietary CAD programs to aid in various designs. Researchers demonstrated progress in miniaturization by showing successive versions of two 900 MHz GIGAFIL duplexers. The mobile version came down from 66 cc in volume and 154 gm in mass in 1983 to 3.9 cc and 20 gm, respectively, in 1996. The handheld version went from 9.5 cc and 30 gm in 1986 to 0.9 cc and 3 gm in 1995 (and 0.5 cc in 1997).

The work on both dielectric block filters and on multi-layer functional substrates was particularly impressive, both leading to miniaturized high-performance components. The latter starts out with thin strips of green ceramic piled in layers. One such device consisted of 21 layers; as many as 600 layers have been contemplated, but not made. The fabrication steps are briefly stated as follows:

In MIMIC product development, Murata uses a multilayer integration technology via multi-layer lamination. The metal used is copper while the inner electrodes are developed by silk screen printing. All processes are controlled by CCD. After the ceramics are fired, the layers are separated by creating small grooves. After cofiring the circuits are inspected and are then plated using Au/Ni.

Two different types of material are used: one of low er=6.1 and the other of high er=25, for antenna and component applications.

Functional integrated technology develops circuits that include antennas, filters, diplexers, baluns, couplers etc. The European market needs the dual band front-end device for very small size phone. Murata has a wire bonding technology for module development. Since late 1999, there is a flip-chip technology for MMIC. SiGe HBTs are used for the CDMA amplifier.

For the European market, Murata is developing an Antenna Switch Diplexer (GSM/DCS) with a SW LPF and switch diodes using LTCC. About 23 components are printed on 21 layers. The design is based on magnetic and electric simulation, sensitivity analysis and monte carlo simulation for optimization of yield, pattern lay out of multilayer circuit, and then trial production. The size of this component is 6.7 x 6.7 x 1 mm.

Filter technology goes to 2 micron thickness, which is expected to be further reduced in order to reach the 1 GHz mark. The transverse dimension may be as high as a few millimeters.

Another aspect of Murata development went beyond the many steps from raw material to finished device, namely the cooperation with and assistance to the end customer, which seemed to be quite close. For example, Murata did not stop at the delivery to the customer of, say, capacitors for EMI (electromagnetic interference) suppression, but also provided a large anechoic chamber to test the performance of the customer's entire system against RFI (radio frequency interference).

FUTURE RESEARCH INDICATED

As on other visits, the Murata hosts had difficulty making long-range predictions 15, 10 or even 5 years into the future. At least two WTEC study team members thought they detected two major trends besides the constant research into better materials, devices, and circuits. One trend was the constant push toward 3D micro-miniaturization, as evidenced here by the multi-layer construction. The drivers are smaller size, lower mass, lower cost, and sometimes better performance (afforded by integration and the avoidance of connectors and connecting 50-ohm cables). Research into new or better ways to do so might have a good payoff perhaps several years away.

The other trend is different. It is the importance of close collaboration between system designer and component developer. An example of such collaboration is the existence of a large anechoic chamber (the WTEC panelists did not see it-it is in Yokohama) at a component manufacturer's plant. It seems not unreasonable to speculate that device engineers need to be more knowledgeable of system needs, and system engineers need to know more about devices. This goal could have a significant impact on the engineering education.


Published: July 2000; WTEC Hyper-Librarian