The Technology And Markets Assessment Economics Essay
In recent years, the emphasis of manufacturing has strongly tilted in the direction of small machines production. Modification of existing structures are aimed at making things smaller. MEMS aim at revolutionalizing almost every category of products and increasing product reliability through a combination of micromachining technology and silicon-based microelectronics at the lowest cost possible. Application of MEMS cut across a wide variety of human endeavours including industrial, telecommunication, medical, transportation etc with an estimated market of about $7bn (seven billion dollars) and an annual growth rate of 14% (fourteen percent). MEMS technology has grown in leaps and bounds over the years and some of these technology trends are investigated in this report, the market and the future of MEMS are also worth considering.
2. INTRODUCTION
MEMS (Micro-Electro-Mechanical Systems) refer to devices that comprise of mechanical components (made via micromachining processes) as well as electrical components which are made from integrated circuit (IC) sequences. MEMS devices are usually greater than 1 μm but less than 1mm and effectively utilize the control prowess of the micro-sensors and microactuators to enable the microsystem in sensing and controlling the environment. (21, (29). The sensors gathers information from the environment and the actuator responds (reposition, pump, filter etc) to instructions received from the electronics after the information received by the sensor is processed. (29)
Whereas some MEMS have not lived up to expectation, other MEMS e.g accelerometers, air-bags, keyless entry systems, reactors for separating blood biological cells, inkjet catridges etc have not only lived up to expectation but also had great commercial success combining the advantages of low cost, reduced power consumption and of course increased product reliability. (30)
2.1 Aims and Objectives
To provide an current overview of MEMS and the likely future developments
To research into the various areas of application for MEMS technology and devices.
To improve awareness on the advantages of MEMS
To examine the current and future market conditions of MEMS
3. Literature review
3.1 MEMS Technologies: the technology involves photographic- based processes and one of its three main features is that it doesn’t require assembly, making it possible to simultaneously build many machines across the same wafer surface (multiplicity), other features include miniaturization which refers to making compactness of devices and also, microelectronics which provides the merger between actuators, sensors and logic to build a closed-loop feedback system. (45). Before the twenty-first century, most of the MEMS process flows were grouped as either bulk or surface micromachining and the choice of micromachining was greatly influenced by device dimension and tolerance. For structures below 10 μm, surface micromachining was used and bulk machining for structures above 10 μm{21}. Before a material is considered for use in a micromechanical structure, some properties are taken into consideration some of which include Youngs modulus, yield strength, density, and residual strength. Silicon is an ideal material used for construction of micro-mechanical structures, it is almost perfectly Hookian, tough and immune against fatigue failure, it is light and available in highly pure forms. It is used in development of complex 3D microstructure based on its different reactions to chemical etchants according to crystallographic orientation. MEM therefore starts with a single crystal silicon wafer. (8).
3.2 Bulk Micromachining: This fabrication technique builds mechanical elements starting with a single crystal silicon wafer, unwanted paths are etched leaving behind a desired mechanical device. (28). To obtain the desired part, the wafer is first photo-patterned after which it is then submersed in a liquid etchant e.g. potassium hydroxide (KOH), which etches exposed silicon away. The etch rate is highly a function of KOH concentration and temperature. . (28,15). Bulk micromachining range has been increased by two additional processes i.e. deep anisotrotopic dry etching and wafer bonding, used simultaneously, these techniques would construct 3D complex microstructures e.g. micropumps. (45). According to Mcwhorter, the major limitation to bulk machining is the inability to fabricate complex, sophisticate devices. (28).
3.3 Surface micromachining: this process involves repetitive deposition, photo patterning as well as etching of thin structural and sacrificial materials (film) from silicon and silicon dioxide respectively. At the end of the process, the wafer is placed in Hydrochloric acid, the sacrificial materials result in gaps which are etched away and the structural materials form the functioning mechanical elements.{32,28,45}. Polysilicon surface micromachining is the most widely used surface micromachining technique. (45) Texas instruments inc. Employed this process in its fabrication of the digital micro mirror {10}. In applications where sophisticated mechanical elements are needed, surface micromachining provides the solution although with a little more cost. {28}
Fig1.http://www.swri.org/3pubs/ttoday/winter04/images/page9.jpgFig. 1.7. Cross-sectional schematic demonstration of surface micromachining. (a) Sacrificial layer deposition, (b) definition of the anchor and bushing regions, (c) structural layer patterning, and (d) free-standing microstructure after release.
Fig.2
Fig1: Cross-sectional schematic demonstration of surface micromachining. (a) Sacrificial layer deposition, (b) definition of the anchor and bushing regions, (c) structural layer patterning, and (d) free-standing microstructure after release. Fig2. {23}
3.4 LIGA TECHNOLOGY: It is one of the prominent micromolding processes and the term LIGA is a German acronym which consists of letters LI (RontgenLithographie), G (Galvanik) and A (Abformung) which translates into X-ray Lithography, electroplating and moulding respectively in English language. (6). This technology uses X-ray lithography relatively high aspect ratio devices.{28,45}. High aspect ratio is possible as a result of high penetration power of short wavelength X ray exposed to photo sensitive materials {27}. The source material in this technique is an X-ray sensitive polymeric plastic layer applied on a substrate which in most cases would be a metallic base plate. Properties of the electroplated material can be customized with respect to magnetic properties, wear resistance and hardness. {31}. LIGA is relatively less expensive and slow but has been used in the production of wristwatch gears, spectrometers etc {28, 37}.
Fig 3:LIGA process sequence
(a) Exposure(b) Electroplating(c) Finishing to height(d) Stripping and removal of substrate
Dedicated to high-precision microfabrication. {31}
3.5 Advantages of MEMS.
1. Reduced cost of production since batch fabrication technique is used in manufacturing miro mechanical systems. (29)
2. Provides increased possibilities by its ability to defy gravity and inertia (14)
3. Intelligent machines with the collaboration of electromechanical elements as the “arms” and “legs” and electronics as the “brains” and [14]
4. Small size and weight makes it useful for portable device or applications (14)
5. It is a diverse technology with a very broad scope of relevance. (29)
6. Combining the efficiencies of electro-mechanical elements as MEMS are intelligent machines. (14)
3.6 MEMS DEVICES
Sensors: which include Pressure sensors, Chemical sensors, biomedical and biosensors, optical sensors, acoustic wave sensors, inertial sensors (accelerometers) used in vehicles. {24, 18, 25 }
Actuators: these include micropumps, linear and rotary motors, grippers, relays and switches {24, 18}
3.7 MEMS SENSORS
Sensing can be defined as ability to transform energy in the environment to energy within a system {13}. Sensors perform the role of information gathering in the system. It converts physical actions it notices from mechanical, chemical, magnetic or optical quantities into either digital or analogue electrical signal {18, 33}. A sensor is called Transducer when it gives an output signal proportional to the physical quantity it measures. It is capable of automatic correction and calibration, and dynamic response to unstable conditions. Sensors are of two classes: passive (modulating) or active (self-gathering) {24, 33}.
Types of sensor
Product
Manufacturer
Technology
Application
Size
Cost
Weight
Inertia sensor(4)
Single axis accelerometer
(ADXL78)
Analog Devices
Surface micromachinning
Vibration monitoring and control, crash/impact detection
5*5*2
$5.66
Tiny UFDN specification
Acoustic sensor(3)
Digital microphone
(AKU2002c)
AKUSTICA
Surface mountable
Pc peripherals, wireless headset, microphone arrays
3.76*4.72*1.75
Low cost
Ultra small
Chemical sensors(19)
Micro motion density and concentration meters
Emerson process Management micro motion
4 wire (100 ohm PRT)
Used as transmitter, metering of crude oil, and non aggressive process liquids
863*1027
$1.63-$2.10
22kg
Pressure sensor(9)
Barometric pressure sensor
(SMD 08x/28x)
Bosch
Piezoresistive surface micromachinning
Automotive engine management application
Standard package
Not stated
compact
Temperature sensor(40)
Analog temperature sensor
(STLM 20)
ST electronics
Surface micromachinning
GPS devices, medical instrumentation, PDA devices etc
Standard
compact
humidity
Digital capacitive humidity sensor
Sensiron
CMOS technology
Climate control, automotive industry, transmitters etc
small
Low cost
Ultra small
3.7.1. Capacitive Pressure Sensors: these sensors are based on the pressure applied which alters the distance between two electrodes (one fixed, the other moving relative to it) and results in a change in capacitance. With pressure application, the flexible electrode deflects, the gap between electrodes decrease and the capacitance increases. {44 ,33}
More recent capacitive based micro sensors have been developed through improved silicon etching, silicon fusion bonding and use of finite element modelling. (44). The device consists of two silicon substrates bonded together with a silicon di oxide layer between them. It requires no metalised electrodes because silicon wafer forms both the mechanical sensor and capacitor electrode. The top silicon substrate is etched and forms corrugations in the diaphragm which defines the diaphragm characteristics under pressure. Both free bonded wafer surfaces are coated with 1m aluminium to enable forming of top and bottom contacts by wire bonding and conductive epoxy respectively. (44). Capacitive pressure sensors are characterised by high pressure sensitivity, low power consumption and fields of application include biomedical, automotives and space {33, 2}.
http://www.usitt.ecs.soton.ac.uk/images/capfig1.gifSchematic of capacitive pressure sensor{2}
3.7.2. Chemical Sensors: sensing in these devices are based on sampling, the collected samples are allowed to react with some elements of the sensor thus producing an electric output. They measure the chemical nature (concentration) of it surrounding by incorporating a chemically selective membrane or layer while having a physical sensor {11, 20}. Some important factors of necessity for chemical sensors to meet an application need, these are: Sensitivity which is concerned with the sensors ability to sense chemical species within interest range; Selectivity, which deals with the sensors ability to detect these species even in the presence of interfering gases which can as well generate response from the sensor; Response time which is concerned with the time taken for the sensor to generate a reasonable signal when a change occurs in the chemical environment; Stability is therefore the extent of change of the sensor baseline and response with respect to time.{21}.
{12}
3.8 ACTUATORS: These are devices that produce motion and can be grouped into either electrical, rotary, and linear actuators, it can also be further classified in terms of actuator action and thus we have double acting, single acting actuators, furthermore, it can be classified on the basis of operating media and as such we have pneumatic actuator and hydraulic actuators. They can also be grouped as electrostatic, thermal, magnetic and piezoelectric {33, 7}. They are three-dimensional mechanical structures and can be fabricated using lithographic and non-isotropic etching technologies {22}
3.8.1 Thermal Actuator: They are non-electric motors that produce linear motion when a temperature change occurs. With an increase in temperature, the thermal sensitive material in the actuator expands pushing the piston to the designed length, the piston returns to original state when a temperature drop occurs and the thermal sensitive material contracts. The temperature range is between 86C-572C. The piston travel is called stroke and can move within the range of 0.015-0.5 inches, they do not require outside power source to produce motion and this resultant motion is used in operating a large variety of devices, including switches, valves and clamps {42,43}. This is a strong type of actuator, common examples include bimorph and bimetallic actuator. {13}
thermal actuator diagram Thermal Actuator {43}
4. MEMS MARKET ASSESSMENT.
The demand for MEMS products are largely influenced by their low cost, compact size as well as light weight {34, 35}. MEMS is an integration on silicon chips through micro fabrication technology which comprises of actuators, mechanical elements and sensors {34}. This technology has found an array of applications in virtually almost every sector of human endeavour ranging from health, IT, transport etc [8, 21]. The global economic recession has had its adverse effects on so many industries and the MEMS market takes no exception. We shall consider the whole MEMS market with attention given to some specific aspects highlighting where the upward and downward trends have occurred. MEMS applications have seven major fields of application: consumer, automotive, medical and life science, aeronautics, defence, industrial, and telecom with the automotive application having highest growth rates of 3.5% over 2007-2010. {38}
MEMS have added value in many ways which include increased product performance, high volume production which has reduced the price of actuators and sensors and also, addition of new functions with in-situ measurement {46}. Between 2002-2005, the focus was on activation of airbags and new applications were found in the mobile phone industry. North America dominated the production of MEMS devices by possession of 41% production followed by Japan and Germany. {18}. some of the major challenges of the time were the differences between product and technology lifetime and the length of time involved in MEMS development. This era saw the top 30 companies with the highest profit as high as 650million dollars. About 7 companies were expected to die between 2006 and beyond {18}
MEMS devices performance {47} MEMS Fabs. {18}
Between 2004-2008, MEMS technology witnessed tremendous progress in areas of the accelerometers and gyroscopes {46}. In 2006, the MEMS industry attained a compound annual growth rate of 14%, with a 25% rise in amount of MEMS devices manufactured and a total value of 6billion dollars. The market was hugely controlled by the automotive business and consumer application. In the 2007 ranking of the “Top 30” MEMS manufacturers by Yole, Hewlett Packard Corp. Was first to cross the ($850million) annual MEMS revenues margin due majorly to its inkjet printhead business. The MEMS market had a value of $7.1 billion in 2007, had a decline in 2008 to $6.8 billion but slightly increased to $6.9 billion in 2009. In 2010 and following years, an annual growth of 12% is anticipated. {38, 16, 47}. Year 2007 yielded some new MEMS devices such as oscillators, dual-axis gyroscopes, and auto-focus etc., Two billion units of MEMS devices were produced which increased to 2.5 billion in 2008 and expected to reach a world-wide value of 6.7 billion by 2012{ 38}.
According to Yole development reports, the pressure sensor market had stabilised at a value of about (US$1billion) and new products with great marketing potentials include Micobolometers, microfluidics for diagnostic applications, defence applications and Si microphones{46}. The defence sector is said to be witnessing an impressive growth of 21% as a result of the use of high-value inertial MEMS. According to the report by Yole, a total of 150 MEMS applications were observed. RF-MEMS is predicted to have 50% growth, micro tips and probes 22%, silicon microphones 32%, micro-fluidic chips for diagnostics 23%, micro-fluidic chips for drug delivery to be 42%,and microbolometers 20%. Of all the MEMS devices, the accelerometers used in human-machine interface looks most-promising with a cumulative aggregate growth rate (CAGR) of over 120% and $500M market value beyond year 2010{38}.
{48}
{47}
{47}http://i.cmpnet.com/eetimes/eedesign/2010/rcjMEMSmarket.jpg
http://i.cmpnet.com/eetimes/eedesign/2010/rcjMEMSmarket.jpg
Market Avenue, in a report on the MEMS market in China report that a fast growth of over 100% occurred between 2004-2007 majorly because of the great success of Nintendo Wii and Apple iPhone, in 2008, the global economic recession resulted in decreased production and shipment however, the market was characterised by 30% in automotive electronics sector, 40%-plus share in the global inkjet print heads output, 70% share in the MP3/MP4 player output, 80% share in the notebook PC output, accelerometers and silicon microphones. It is expected that with rising mass production techniques and R&D in the MEMS market, there will be emergence of new products in the near future. The Chinese MEMS market is focused on new products such as batteries, oscillators, and storage devices to be deployed in various MEMS applications. It is widely believed that the arrival of new products and applications will energise and diversify the future MEMS market in China and globally {27}.
In Japan, the domestic market share in 2005 was about 440 billion Yen (4.8 billion dollars). A prediction is made that places this value between (1.17-1.35) trillion Yen (12.7-14.6 billion dollars) in 2010 and 2.4 trillion by 2015. {41}. The automotive and the telecommunication sectors are the controllers of the market accounting for 70% of the market this year (2010) and expected to drop in the years following. MEMS sensors accounted for 57% but to decline to about 55% this year (2010) and further reduce to about 51% by 2015. Markets predicted for gradual growth include microfluidics, biological and chemical MEMS. Results of the Japanese market survey shows that the current percentage of MEMS related business conducted at MEMS-related companies is low but expectations for MEMS are high and suggest a trend of companies actively expanding their MEMS business. {41} MEMS-related
Industries view MEMS devices as the core of Japan’s future principal manufacturing industry and wish to expand into this field, and the key to market development is development of MEMS technologies based on new structures and materials development. {41, 1}
http://www.mmc.or.jp/e/outline-e/parts/image13.gif
http://www.mmc.or.jp/e/outline-e/parts/rd_scenario.gif
MEMS Market, Japan {1} MEMS Market, Japan {1}
5. DISCUSSION
The MEMS market has been on a downward trend following the global economic recession but at the turn of the year, the market seems to be showing better prospects. According to Yole, the available production infrastructure is still sufficient enough to cater for the growth anticipated in the next two years. The MEMS market no doubt is thriving and would definitely survive many years to come, up till now, about 2.5 billion MEMS units have been sold and this is expected to rise to about 6.7billion within the next two years, thus indicating better days ahead. 2012 market forecast for MEMS products, predict a $14B market value representing a 14% CAGR of for the periods 2007-2012 {16, 38}. The micro electromechanical systems (MEMS) market will hit $10B by 2011. The automotive MEMS market will grow rapidly as the number of MEMS devices per vehicle increases from to about 60 MEMS as compared to a current value of 40. {39} In 2012, micro displays, inertial MEMS, consumer applications, and emerging MEMS devices such as, auto focus, energy harvesting systems etc will account for over 40% of MEMS market. Consumer, telecommunications, defence and medical and life science will contribute to MEMS market growth beyond 2010, with growth rates of 11% ,40%, 21%18%, respectively.{36 ,38}
Growth of MEMS has been widely driven by the compulsory safety rules , demand for more product functions, collaboration of manufacturers, smaller and lower cost sensors etc. in the United States (US), New application for products such as gyroscopes, displays, accelerometers, etc., are also contributing to MEMS growth world-wide, thus resulting in larger MEMS market.{36}. An area of concern however, is the choice of final packaging because it constitutes about 60% of total cost. The current primitive state of the packaging of MEMS systems and devices needs to be highly improved upon and currently, MEMs manufacturers are getting more focused on R&D to improve the packaging process and develop better packaging for their devices.{49}. New materials for MEMS such as polymers are also being considered for usage in the future as replacement for silicon and semiconductor currently in use, thereby increasing the variety of materials used and the necessity for acquiring alternate functional systems working simultaneously to perform big tasks [26]. between 2010-2020, the global market for various applications will experience a robust compound annual growth rate (CAGR) and from the fore-going discussion, it is glaring that the future for MEMS surpasses even the year 2020 especially with the technology finding relevance in increased fields of human endeavour and with the effect of R&D by various companies to maximize profit, discover untapped areas of relevance and stay in business.
5.1 CONCLUSION
Prior to this year, the MEMS market experienced an unpleasant era, but presently, with a market value of about $12.5 billion dollars and predicted robust growth rate. Companies are fighting hard to retain and even improve market share. With ever changing dynamics, strong and intense competition, and a growing number of players in the industry, the years ahead look very exciting for the MEMS industry with more fields to explore and more discoveries to be made, doubtlessly, MEMS technology is bound for a very good future{38, 48 }.
