Site: Yaskawa Tsukuba Research Laboratory
5-9-10 Tokodai, Tsukuba
Ibaraki 300-26, Japan

Date Visited: September 28, 1993

Report Author: S. Jacobsen

ATTENDEES

JTEC:

S. Jacobsen
R. Muller
L. Salmon

HOSTS:

Mr. Kabashima Manager
Mr. Matsuzaki Researcher
Mr. Matsuo Researcher
Mr. Shimozono Manager
Mr. Magariyama Researcher
Mr. Mirua Director
Mr. Mikuriya Manager

NOTES

Yaskawa Tsukuba Research Laboratory was founded in 1915, and manufactures motorman robots, electric motors, inverters, controllers, and other products. The company now has sales of approximately $1,670 million per year. It currently has 4,500 employees, with 550 people in research and development departments. The laboratory has 15 people working on micromachines. Yaskawa's facilities are scattered throughout the country. The JTEC team visited the facility at Ibaraki.

Ibaraki's funding comes partly from government funds, but the laboratory spends three times the government amount from internal funds. The laboratory appears to have sufficient funding to support a large, qualified staff, and to maintain good equipment and buildings.

The basic research objective of the company appears to be a long-term focus on product development. The group that the team spoke with was not focused on products for near-term commercialization, but rather was operating in a very flexible way aimed at far horizons. The mix of projects at the facility seemed disjointed, giving the impression that despite their claim for focused development, they seemed willing to diversify the direction of their projects. It should be noted that Yaskawa is the lead group working on the "mother ship" portion of the national (MITI) micromachine program (see MITI/AIST and MMC site reports), and thus does direct a certain portion of its research towards the goals of this project.

Yaskawa representatives showed the JTEC team three project areas: bacterium flagella, robotics, and motors.

The bacterium flagella project is an experimental evaluation of propulsion by observing moving organisms in free swimming motion or with flagella bonded to a fixed substrate so that the body counter rotates. The group observed unwinding and redirected procedures of the bacterium, which some researchers think allow it to follow gradients in search of food, safety, and other desirable results. The Yaskawa group focused on defining actuation methods. Yaskawa and others postulate wall-located proton pumps that cause backflow of charged particles through biomotors to cause actuated rotational motion of the flagella.

The control of teleoperated robots project, with two arm-and-hand slaves and two arm-and-hand passive masters (no force reflection) were demonstrated. The hands included three fingers with multiaxis and spherically-shaped load sensors on each finger tip. System actuators were slow with limited force generation capability. However, problems of both stiction and backlash were substantial.

Viewing systems, including stereo cameras on slaves and magnetic head trackers on the operator, were shown but did not function successfully in peg-in-hole experiments.

The small motors project, where the JTEC team saw small magnetic motors 5 mm in diameter and small electrostatic motors of conventional design. The electrostatic motors were 13 mm in the outer diameter, 5 mm in rotor diameter, and generated a peak torque 10(-6) N-m.

The motors were not micro but mini. There seems to be a question as to whether their motors could ever be manufactured for reasonable costs. No machining was used, but other less economic techniques were demonstrated. The motors consisted of metals and plastics and were fabricated using EDM, welding, drilling, and other approaches. While aware of micromethods such as silicon fusion and micromachining, the Yaskawa group did not seem to be using them.

The Yaskawa group was studying the crossover of advantages between electric and magnetic motors. For their designs, the group showed a crossover at 1.5 mm diameter rotor and a torque/volume of 2 x 10(-8) N-m/mm(3).

QUESTIONNAIRE

A. Advanced Materials and Process Technology

1. What materials and fabrication techniques are most likely to be used in production for MEMS? Will MEMS continue to be based primarily on silicon IC technology?

Silicon that is expected to play an important role in the micromachine technology, is a superior material. It keeps on being the staple material. We use metals (e.g. aluminum, copper) and/or plastics for the insulator (e.g. epoxy resin, polyimide), ceramics, glass for micromachine's materials. Concerning the fabrication techniques, we use the conventional machining techniques, such as the wire electro discharge machining and machining by the machining center (drilling, cutting, grinding, and so on), and other machining. At the same time we use IC technologies, such as photolithography, deposition, etching, and so on.

2. What, in your opinion, is the most important new process or material needed for extending the capabilities of MEMS?

We think that the most important issue is the pursuit of the limit of conventional machining (such as mechanical machining, electro discharge machining and so on). Similarly, we think the fusion of new technologies (such as IC fabrication, thin film technology) and the conventional ones are important.

3. Are there plans to use X-ray lithography for micromechanics?

We have an interest in this technology, but don't plan to use it right now.

4. How attractive is the LIGA process for commercial use in MEMS at the present time? How attractive do you expect it to be in five years? Ten years?

We can't judge this technology now, since the cost and/or reliability for the parts of metallic mold has not been cleared. If they are supplied at a reasonable price, we want to use it for the very small parts such as micro gears and other mechanical parts. We expect it within the next five years.

5. If you are pursuing LIGA and LIGA-like high-aspect-ratio structures, what materials are being investigated and why? To what extent do you feel that structures produced using high-aspect etching will be competitive with those formed by plating?

The formation of an amorphous alloy has been under investigation (by Dr. Saotome, Gumma Univ.) using a characteristic of super plasticity. A stereolithography process has been investigating (by Dr. Nakajima, Tokyo Univ. and Dr. Ikuta, Kyushu Institute of Technology).

6. What are the prospects for a low-temperature wafer-scale bonding process for MEMS? How low in temperature can we go? Do you feel metal-metal, silicon-glass, or other interfaces are most promising?

We haven't studied bonding processes.

7. To what extent will silicon fusion play a role in MEMS? Is the area coverage sufficiently high? How much of a real problem is the high bonding temperature?

Silicon fusion will play an important role on MEMS based silicon technology. It is generally said that high bonding temperature will affect the mounted logic circuit. Our research activities have not reached to combine mechanics and electronics on the one chip.

8. What polymeric materials are being explored as photomasks for high-aspect-ratio structures? Is the use of conformal coating processes practical?

This item is not our field. We expect the advances in this field.

9. Polymers for thick photoresist applications are required by MEMS. Are Japanese photoresist suppliers responsive to this need?

We think that polymers for thick photoresist haven't been commercialized. We think Japanese photoresist suppliers are negative about developing new materials at present.

10. Do you feel that nested/stacked wafer-level microstructures based on multiple bonding and/or etch-back operations will be feasible within the next five years? Are they important for MEMS?

Stacked microstructures have advantages for precise assembly, and these will be feasible within the next five years.

11. It appears that precision injection molding could play a major role in MEMS. Would you comment on this, please.

Although this technology will need another precise assembly technique it will play a major role as a fabrication technique of micro parts.

12. Are room-temperature superconductors being explored, and if so, what materials and processing techniques are being used?

We think this item has no relation with MEMS. And this theme doesn't investigate in our company. Maybe, in Japan, many people are engaged in the research of this field.

13. Do you expect major advances in micromachining curing the coming decade? Will photo-assist etching or new etch-stops emerge to play a major role? What other technology additions do you consider promising?

We expect major advances in micromachining. Moreover we must drive forward ourselves.

14. What are the most important attributes you would insist on for a MEMS processing tool?

Mass productivity and ability [to make] real 3D microstructures.

B. Sensors and Sensing Microstructures

1. For which sensed variables and types of sensors will MEMS technology have the greatest importance? What are the key advantages of MEMS technology for these sensors?

From the view point of developing micro actuators, the rotational speed sensor, positioning sensor, electric current and voltage sensor have the important role. The advantage of MEMS is fusion and/or combination of sensors, electric circuits and actuators.

2. Approximately when will the new sensors under development today based on MEMS technology first appear in the market place?

Accelerat[ion] sensors, pressure sensors and flow meters [are] already [on] the market.

3. How can MEMS technology be used to improve existing sensors? What sensor types are likely to be improved the most?

We haven't participated in the development of sensors, so we don't have any comments.

4. What new sensors can only be developed using MEMS technology? How does MEMS make these new sensors feasible?

The answer is similar to No. 3

5. To what degree is self-testing likely to be possible with sensors? Will this be a major role for MEMS technology?

Self-testing will not be a major role, even if it will be [possible] to realize.

6. After pressures sensors and accelerometers, what is the next major sensor based on MEMS that will be mass-produced in high volume?

We don't have any comments.

7. To what degree are feedback readout schemes likely to be important in sensors? Will these feedback schemes involve MEMS?

We can't understand perfectly the meaning of this question.

8. What are the principal problems in the use of scanning surface probes (e.g. tunneling current) as an approach to high-sensitivity sensor readout? Is this approach likely to find wide application?

We are interested in these probes as peripheral technique region. But we don't have enough experiences for this region to comment.

C. Microactuators and Actuation Mechanisms

1. Can designs using arrays of microactuators achieve large and useful forces? Are there other devices similar to the large optical projection displays that have been reported that can be realized using MEMS technology?

Gathering arrays is one method to produce large force. One problem is how to control them simultaneously. We don't know the optical projection displays which are realized by MEMS.

2. Considering their importance to MEMS, in what order of importance would you place the following microactuation mechanisms: shape-memory alloys, electromagnetics, electrostatics, thermal bimorphs, piezoelectric bimorphs, piezoelectrics, electrostriction devices, [and] phase-change devices? How many of these do you expect will find commercial applications in high-volume products?

We are studying electromagnetic and electrostatic micro actuators. One reason is that these technologies are traditional ones of our company and the other reason is that these actuators are the most suitable actuators for the rotational motion. The selection of actuators must depend on the applications. So, the order of importance is case by case. We think at present the order from a viewpoint of volume, is as follows. First: electrostatics, second: electromagnetics, third: PZT and fourth: SMA.

3. What are the most reasonable candidates for prime movers for microactuation?

We think electrostatic actuators are.

4. To what extent can sticking problems due to surface forces be suppressed in microactuators? Will these problems seriously constrain the practical application of microactuators based on narrow gaps?

It will become a serious problem. Surface improvement and/or no mechanical contact techniques will be importance.

5. What is the most promising candidate for a microrelay? Where are such devices most likely to be used?

When it is necessary to move at high frequency range, electromagnetic and/or piezoelectrics are suitable. The other case, thin film SMA will be the candidate.

6. What are the main design issues in microfluidic systems? Where will such systems find their primary application?

This item is not our field. We don't have any comments.

7. What designs are most likely to be adopted for practical microvalves and micropumps? What is holding up the practical realization of these devices?

We think the type of membrane pump with electrostatic actuation is most practical. The bottlenecks for the practical use are reliability and life time.

D. Sensor-Circuit Integration and System Partitioning

1. Will MEMS technology lead to complete microminiature "instruments on a chip?" For what types of instruments?

There are many issues to realize "on the chip machine". Its application is now under investigation.

2. Will MEMS technology combine sensors and actuators into complete control systems? If so, what types of control systems will be most affected?

Yes, it will. About the specific types of control systems, we can't judge them.

3. Are systems involving sensors, actuators, and embedded microcontrollers likely to be realized in monolithic form or will they be hybrid? What factors are driving for monolithic integration for what types of products?

We don't have a clear answer concerning monolithic form. We think hybrid form is more practical than the monolithic one.

4. What levels of integration (transistor count) are we likely to see on MEMS chips by 1995? By the year 2000? Are full microprocessors needed or realistic?

We don't have any clear opinions. Full microprocessors will not be needed, since each device will have its own processor.

5. To what extent will embedded microcontrollers be used in (possibly hybrid) integrated sensing nodes -- high-end devices only, or will they eventually become pervasive in even low-end products?

First, these are used in high-end devices, after that these are expanded into low-end products.

6. What are the prospects for adopting sensor bus standards, at least in specific industries (automotive, process control, HVAC)? How important is the evolution of such standards to the development of MEMS?

In near future, the standards will have to be established on a worldwide scale. We think this is a very important issue.

7. Will sensor calibration continue to be done in hardware (laser-trimming or EPROM) or will it evolve to digital compensation in software? Is this an important issue in MEMS development?

Both techniques will be necessary. The final fine adjustment will be done by digital compensation in software.

8. Will a few standard processes emerge to dominate sensor-actuator-circuit integration or will widely divergent processes continue to be the norm in MEMS? What issues will determine the answer to this question?

The scale of the market is a dominant factor. But we don't exactly understand it's scale.

E. Advanced Packaging, Microassembly, and Testing Technology

1. What are the general directions for progress in packaging MEMS? What are the principal challenges here?

Our research [has not] arrived at the packaging stage. So, we don't have enough comment. Some techniques (such as bonding, assembling and precise positioning) should be investigated.

2. What will be the application and impact of MEMS on the packaging of sensors?

We have no comment.

3. How much of a problem is die separation for surface micromachined devices? Is this optimally performed after release?

We have no experiences with this technique. We don't have any comments.

4. How important are the chip-level packaging schemes now under development to MEMS devices and systems? Is the increased process complexity worth it?

The answer is similar to No. 3.

5. Are common packaging approaches across many types of devices feasible or will packaging continue to be very application specific?

The answer is similar to No. 3.

6. What viable techniques exist for coupling force from integrated microactuators while protecting the device from hostile environments? Can mechanical microactuators only be used inside hermetic packages?

The answer is similar to No. 3.

7. To what degree should MEMS continue to focus on monolithic silicon microstructures and to what degree do you think it is really better suited to milliscale integration with components combined using microassembly techniques?

The answer [to] this question depends on the application. In the medical application micro scale will be required and monolithic silicon microstructures will be suitable. On the other hand, in the industrial application the milliscale structures will be needed. In this scale the assembly technique will be suitable for making the structures.

8. Are there microassembly techniques that can be sufficiently automated to make millielectromechanical devices in high volume at moderate or low cost? What are the generic barriers to such devices and techniques?

We think the millielectromechanical system will act the major role, especially for the industrial use. Our main aim is the application of micromachines to these fields. We agree to the problems of assembly techniques have not been settled.

9. What techniques are available for testing MEMS structures after encapsulation/packaging? What happens when they are no longer viewable?

It is impossible to test after packaging. The only means to solve is to test every part at each process.

F. MEMS Design Techniques, Applications, and Infrastructure

1. The term "MEMS" has many meanings. Could you tell us your interpretation?

In general, MEMS means the system consists of the sensors, actuators and circuits based on silicon technology. We think MEMS and Micromachine have similar meaning. It means micro mechatronics system that consists of small parts (below mm size), and it will be made of various materials.

2. Is there a MEMS technology driver equivalent to the DRAM in the IC industry? If so, what is it?

We think it is sensor.

3. Is the integrated-circuit industry the principal application driver for MEMS? If so, what are the alternative drivers during the next decade, if any?

The industries [related to] the applications of MEMS will be the drivers (automotive, medical, etc.)

4. In what sensor application areas do you see MEMS technology having the greatest importance? (Examples might be: automotive, medical, robotics, consumer products, etc.) What are the key advantages of MEMS technology for these applications?

First, MEMS [will be] used for high-advanced [advantage?] technology such as automotive, medical and robotics. Gradually, it will be expanded to the consumer products. We don't know the key technology at present.

5. What will be the application and impact of MEMS on the interfacing of sensors to the environment?

We have no ideas.

6. Looking ahead five years, what new MEMS-based sensors and sensor applications do you anticipate?

Main products will be the accelerometers and pressure sensors. We expect progress [in] rotational sensors and positioning sensors.

7. In what time frame do you anticipate MEMS technology having the most impact on sensor products (for example, three years, five years, ten years, etc.).

Accelerometers and pressure sensors will be commercialized widely within three years. Compact sensors that detect rotational speed and position will be developed within five years.

8. What is the prognosis for MEMS foundries? Are they needed? What technologies would need to be present in a MEMS foundry?

MEMS is now [a] developing technology, so we don't have clear image for MEMS foundries.

9. What is the state of the art in MEMS reliability? Where are the principal problems?

MEMS [has not reached] the stage [where] we can discuss reliability. It will take us some time to reach [that] stage.

10. What is the "state of the art" in MEMS designability? How important are CAD tools for MEMS? Do you have an active CAD effort for MEMS in your organization?

We are trying to adopt CAE (CAD) technology for micromachine design in the fields of electromagnetic, electrostatic, thermal and mechanical analysis.

11. What priority would you place on the creation of a central MEMS database of material and design parameters? Does your organization have an active project in this area?

We don't have any concrete plan for [a] database system.

12. How much funding is being directed into MEMS research and development in your organization? What percentage is this amount of the total R&D budget?

We can't say the amount of the budget. Fifteen members have been connected with research [in] micromachines. (Yaskawa has 4500 employees and about 550 members are engaged in development and research activities.)

13. In your view, is enough funding available to support MEMS research in Japan? In the world? Are the principal bottlenecks to more rapid progress money or ideas?

We can't say we have enough fund[s] to install the expensive manufacturing equipment. We think the progress of MEMS depends on the idea.

14. What portion of your R&D funding for MEMS comes from internal, government or other sources? Has increased government funding had a major impact in your organization?

We participate in the MITI's ISTF program and are awarded grants for our research. But we spend twice or thrice as much as the money we receive.

15. What percentage of your research is directed toward specific products? Toward basic research?

Our research activities mainly consist of the development of the specific products. We have not been engaged in real basic research. In Tsukuba Lab., a few themes such as flagellar motor are directed toward basic research.

16. What emerging technologies do you see as having the largest influence on MEMS and why (i.e., LIGA, superconductors, submicron ICs, piezoelectrics, thin-film magnetics, etc.)?

The micromachine [field has] been very active, so new technologies will appear probably. But at present we don't know what [they are].

17. What are the principal barriers to the success of MEMS?

The key [to] the success of MEMS is whether we can find applications of MEMS which can't be realized without MEMS.

18. What do you believe to be the major competitive technology alternative to MEMS?

We don't know.

19. Are patents a key to commercial success or are base technology skills more critical?

Patents will be a key.

20. The first generation of university graduates who specialized in MEMS are now finishing their degrees. Are employment opportunities for these students plentiful in Japan?

Micromachine research will be continued in many Japanese companies. So, they have enough employment opportunities.

G. The R&D Process (if time is available after discussing technical issues)

1. What percentage of your research is being directed toward a specific problem -- looking at multiple solutions?

More than 90 percent of our research is directed toward a specific problem.

2. What percentage of your product is scheduled for captive use, and why did you choose to keep the product captive?

Fifty percent of our products [are] mechatronics products, and they are not scheduled for any captive uses. The other products [are] heavy electrical products and system products, [and] are scheduled for captive uses.

3. What percentage of your product is scheduled for end sale as a merchant item? Does it replace an existing product for your company or is it new?

We don't catch the meaning of this question.

4. What is the average time from research to market? From concept to research prototype, research prototype to engineering prototype, and from engineering prototype to market?

The development period is from one to five years. On the other hand, the research period is from three to ten years.

5. How do you determine whether to continue a project from research to development and to production? Who makes the decision to continue?

An inquiry committee, which consists of general managers of each division, determines whether the project should be continued or not.

6. How do you determine the potential products from a given technology? What processes are used?

We determine it using the help of our expert knowledge. We use the TQC technique and CE technique for comparison with the conventional technology and another company's technology.

7. Are you involved in joint development with other organizations? What kind (other companies, universities, foundations, etc.)?

We have many joint developments. These are the National project and some projects of Research Development Corporation of Japan, universities and KAST, etc.

7. How are the product goals established, and how are they converted to technical goals?

First we consider the goal of the sale, concerning the cost and market scale. So we develop the ideas which can realize these products using the help of our expert knowledge and the method of TQC.


Published: September 1994; WTEC Hyper-Librarian