Monodzukuri Grand Award for Parts: Incentive Award
In the 2005 2nd Monodzukuri Grand Award for Parts organized by the Nikkan Kogyo Shimbun, Fujikin's "Electric Compact Diaphragm Valve: ECV®" was awarded the Incentive Award. We received the award certificate on March 29th, 2005.
With the same product, we were also honored to receive the Higashiosaka Monodzukuri Grand Award: Gold Award of Excellence from The Higashiosaka Chamber of Commerce and Industry for an excellent new product, new technology, and remarkable growth of a company. This product also received a generous recommendation from Professor Tadahiro Ohmi from the Future Information Industry Creation Department, New Industry Creation Hatchery Center at Tohoku University, which we will present next. We would like to express our sincere gratitude to Professor Ohmi and everyone for their warm support.
2nd Monodzukuri Grand Award for Parts
Electric Compact Direct Diaphragm Valve：ECV®
New Industry Creation Hatchery Center, Tohoku University
Future Information Industry Creation Department
Professor Tadahiro Ohmi
Aiming to create semiconductor manufacturing technology that can be perfectly reproduced with no fluctuations, I have proposed ultra clean technology with 3 principles; ① Completely clean process atmosphere, ② Complete control of non-contaminated surfaces, ③ Complete control of all semiconductor process parameters that influence the results. I have investigated the cause of fluctuations in all semiconductor processes and have developed with many companies; new materials, components, processing technology, surface treatment technology, construction technology, and monitor/control technology that is required for the creation of ultra high performance semiconductor production lines, such as ultra pure gas supply systems, ultra pure water supply systems, ultra pure liquid medicine supply systems, and ultra high performance manufacturing equipment, etc. Within these, I have developed an indispensable electric compact direct diaphragm valve (ECV®) in collaboration with Fujikin Incorporated, a precision flow control equipment manufacturer. It is a gas supply system that supplies all kinds of compositions and concentrations of gases with precise control to the equipment.
The business of information appliances that support digital networking is about to become highly contested and they essentially require a low/variable production for a very wide range of products, which is where semiconductor integrated circuits come in with a strength of being good for small lot mass production. Manufacturing equipment that have the production capacity of sixty silicon wafers per hour, have the ability to produce forty thousand wafers per month with one machine. Currently, semiconductor manufacturing equipment only have the functionality to perform one type of function. By constructing a semiconductor production line with this kind of equipment, and running all equipment at full power, it would be required to process a minimum of twenty five thousand silicon wafers per month. The initial investment for 200 mm wafers would be 100 billion yen, and for 300 mm wafers it would be 200 billion yen, which is certainly a large scale investment that is required and it would be impossible to adjust to the production of semiconductor circuits for digital appliances. If one machine can perform multiple different processes continuously, even with a small production of one to two thousand silicon wafers per month, it would be possible to make a enough profit with all equipment running at full operation.
To convert the industry from a single lump investment type to a staged investment type for the semiconductor industry, our laboratory is putting in all our effort into developing and implementing microwave excitation with ultra low electron temperature and high density plasma equipment that can process multiple different processes continuously.
In order to realize equipment that processes multiple different processes continuously, it is necessary to have a gas supply system that can sequentially switch quickly between multiple different source gases. In manufacturing equipment that processes silicon wafers one by one with a sheet-fed system, the process is usually initiated and suspended by controlling the opening and closing of the endpoint valves. If we try to perform multiple different processes one after another with the same equipment, it is necessary to set the timing and concentration of multiple different gases for the different processes, which is then supplied to the surface of the silicon wafers.
To perform a process with perfect reproducibility, the multiple gases that are supplied to the surface must be supplied at the set timing and concentration without any malfunctions. A pneumatic valve, also known as an automatic valve, has a very airtight construction, and it's characteristic is that it can be easily controlled if the fluid pressure is less than 1 MPa. However, 90% of the response time is required to replenish and release the gas in the actuator of the pneumatic valve, which causes the opening and closing of the valve to be dozens of milliseconds slower. Moreover, the response time of the valve is different depending on the length of the instrumentation tube supplying the gas and the pressure it is supplied at, which is a problem. As a result, there is a time lag between the valve's operation sequence and the actual movement of the valve, which produces backflow and defects on the surface of a circuit board are caused by the fluctuation in the initial gas composition and pressure.
The ECV® developed in collaboration with Fujikin opens and closes the space between the valve seat and the valve seat weight, by using the valve weight and vertical motion together with the force of the coil. This removes the operation time of replenishing and releasing the gas of a drive shaft in a pneumatic valve, which makes the time required to open and close the valve a few milliseconds, and this quick response time is its main characteristic. Also, by developing a magnetic body material with an iron/cobalt alloy or iron/nickel alloy, which have a saturation magnetic flux density of 2T (Tesla), the volume of the magnetic body material is considerably lower, which allowed us to make the flow control valve more compact.
The excitation current supplied to the coil is separated into the large initial electric current to drive and open the valve, and a small electric current to maintain the open state of the valve. This electric current generates the magnetic field for the aforementioned coil, and the magnetic body is quickly pulled towards the coil. With this separation, energy consumption for the drive component is kept low. By combining the ECV® with the simultaneously developed flow controller which controls flow rate by gas pressure, it became possible to control the composition and pressure of the source gas inside the equipment with high precisionv from the beginning of the process, and is achieved by just opening and closing the ECV® at the endpoint.
The ECV® removes all worries such as backflow generated by the response time lag of the gas pressure, instrumentation tube length, and individual differences of the operators. Also, it is possible to constantly open and close the valve with a quick electric signal, and you can make a compact gas supply ssytem with high reliability.
Furthermore, ultra large scale integration (ULSI) of the functional components have been composed of monocrystalline materials or amorphous materials. However, in order to further improve functionality and performance, polycrystalline materials such as ferroelectric thin films and high dielectric constant thin films are being introduced to functional components, and we are now moving to silicon technology. Ferroelectric thin films and high dielectric constant thin films usually contain oxygen compounds with 3 or 4 elements, and if you want to show the full capabilities of ferroelectricity and high dieelectric constants in a film as thing as possible, it is necessary to have film formation technology that can completely control the element composition at the monoatomic layer level. With the current pneumatic valves that open and close by air pressure, it is absolutely impossible to completely form a film of the polycrystalline material at the monoatomic layer level.
By using the ECV®, it has become possible to completely control the element composition of the film forming process at the monoatomic layer level with a feed-forward system.
In our research facility, we have fully adopted the ECV® in our gas supply panel for manufacturing equipment. By combining welded fittings with no external leaks, highly reliable welding technology, and passive metal treatment technology, we have been able to supply high purity gas to the process chamber, just by opening and closing the endpoint valve at the required time. The ECV® has already been fully installed in manufacturing plants for semiconductors and flat screen displays, and is contributing to the improvement of reliability, rate of operation, and productivity in the production line.
I am confident that the importance of the ECV® will become bigger and bigger as we move to a new generation in the semiconductor and large display industries, and I recommend this technology for the 2nd Monodzukuri Grand Award for Parts.
January 20th, 2005
The Electric Compact Direct Diaphragm Valves (ECV®) are mainly used as a valve to supply particular source gases for semiconductor manufacturing equipment. In general, due to the cleanliness specifications for the valve, the output power of the valve to close is different from that of solenoid valves and is very large.
Actuators in clean specification valves have mainly been air operated due to the superior thrust they generate, and although compact clean specification electric valves have not yet appeared on the market, solenoids made of special alloys are able to generate large thrust and compact electric valves have been developed alongside air operated valves. Its characteristic is that the valve is operated by electric and a quick response time is possible. Compared to general conventional air operated valves, it is possible to quickly open and close the valve with less delay, and the main features are:
Specifications of ECV®
Construction of ECV®
Semiconductors are manufactured by semiconductor manufacturing equipment by using all types of gases (corrosive gas, poisonous gas, etc) in the manufacturing process for thin film deposition and etching.
The equipment that supplies the gas is called a gas supply system, but a direct diaphragm valves of clean specification that control the flow of gas is used in the gas supply system.
With current general air operated type valves, the response time of the valve fluctuates depending on the operation pressure and operation pressure supply tube.
These occur with the above response time fluctuations:
・A solenoid made of special alloy with a saturation magnetic flux density of more than 2 tesla is used to match the diameter of the actuator in the electric valve with the conventional air operated valve.
・By using a solenoid for the actuator, a valve response time of less than 5 msec is achieved by using the least amount of o rings possible, which are a cause of resistance during operation in conventional air operated valves.
ECV® Actuator Cross Section Schematic
・Although a large amount of power is required at the time of solenoid operation, to acquire that power only requires a large electric current for 5 ms after the signal input, which generates a powerful thrust.
・Since the electric current required to maintain the solenoid operation is small, the electric current is reduced to lower energy consumption and prevent heat generation by the solenoid.
Electric current control graph for the dedicated power supply unit
The measurement system for the valve response time is shown in the next figure. To check the operation of the valve, the valve body is cut so that the movement of the metal diaphragm can be measured directly by a laser displacement sensor. The valve's operation signal is monitored by an oscilloscope when the operation signal is sent to the dedicated power supply unit.
Valve response time measurement equipment schematic figure
Currently the most commonly used air operated valves (closed type) that operate with a 3 way solenoid valve for pressure control, have operation time lag called off balance. When going from the closed state to the open state, this is the time it takes from filling the valve cylinder with the operation pressure for the solenoid valve, till the piston can begin to move. With this operation time lag, the response time for air operated valves is fifty to sixty milliseconds. The response time also fluctuates depending on how many valves are used simultaneously and the length of the tubes.
With the ECV®, the above measurement results are achieved due to it being directly driven by a solenoid, and opening and closing the valve has a response time of less than five milliseconds which is around a tenth of the response time for general air operated valves.
By using the ECV®, it is possible to directly operate the valve with electric, and things like the 3 way solenoid valve, air tubes and operation pressure supply (compressor) are not required as they are in a system which uses the conventional air operated valves. In addition, a large current is required at the time of operation, but at the time of operation holding, the current value is reduced to suppress the power consumption.
The amount of shipments made from Janaury 2004 till December 2004, are 604 valve heads and 60 sets of dedicated power supply units. In the future, the semiconductor industry will be further refined and more advanced processes will be required, and we predict that there will be more applications for high performance valves.
We have taken into account safety by acquiring the CE mark for the 4 channel dedicated power supply unit, and American UL standard.
(1) Name：Fluid control valve and fluid supply/exhaust system
Application number：Patent application 10-525441
(2) Name：Solenoid operate metal diaphragm open/close control valve
Application number：Patent application 11-047831