© 2005

Silicon Microphone Industrial and market focus

© 2005• 2

Content (of the global report)• 6. Silicon Microphone Technology Overview

(p.74)• Microphone definition• Advantages of Silicon Microphones vs. ECM• Silicon MEMS Technology• Detection principle description

• 7. Silicon Microphones Manufacturing Challenges (p.91)

• Design• Processes• Cost analysis on several device types• Opportunity to decrease price• Development costs per players

• 8. Appendix

• 8.1 General overview of the MEMS Business (p.99)

• MEMS History & Genealogy• MEMS market challenges

• 8.2 MEMS Manufacturing Overview (p.115)• Key Differences between MEMS and IC Lines• MEMS typical flow chart• Micromachining technologies• Why integrated MEMS: from MEMS to

Microsystems• MEMS processes challenges

• 1. Executive Summary (p.3)

• 2. Methodology (p.4)

• 3. Market Opportunity (p.9)• ECM markets Key points• Market opportunity for MEMS microphones• Description of applications• Market evaluation per application• Market trends

• 4. Industry Status of Development (p.31)• Product introduction schedule• Silicon Microphone Player Profiles• Current partnerships

• 5. Industry Organization and Trends (p.62)• Business model comparison• Evolution of the ECM competition• From Analog to Digital evolution• Technology winners: monolithic vs. several chip

solution?• Key drivers of microphone manufacturer and

handset manufacturers relationship • From microphone device to microphone module• M&A

© 2005• 3

3. Silicon Microphone Market Opportunity

© 2005• 4

3. Silicon Microphone Market Opportunity Market Descriptions

• Silicon Microphone potential applications are identified on the schematic above

• Market penetration is estimated to be in the following order:1. Consumer2. Medical3. Automotive4. Industrial

SILICON MICROPHONE

CONSUMER

INDUSTRIAL

AUTOMOTIVE

MEDICAL Active noise cancellation

Hearing aids

PDAs

LaptopsMobile phones

Acoutics crash sensors

Active noise cancellation

Hand free sets

PCs

© 2005• 5

3. Silicon Microphone Market Opportunity Market Estimation

• The total available market has a great potential.– 2008 global penetration rate is only 16%

SiMicro Total Market

0

500

1000

1500

2000

2500

3000

2004 2005 2006 2007 2008

Mun

its

0

50

100

150

200

250 M$

TAM (Munits)SiMicro volume (Munits)SiMicro market value (M$)

© 2005• 6

4. Industry status of development

© 2005• 7

4. Industry status of development Players detection principle

• Three types of silicon microphones have been identified so far:– Capacitive detection is of high growth and interest today

• Dedicated to low cost and moderate performances devices: i.e. the replacement market of the ECM– Microflow detection is related to fine sound measurements

• Oriented toward measurement market– Optical detection is more military /security oriented

• This detection is very accurate and allow lot of noise reduction• It main feature is to be undetectable compared to other technologies• They are mainly developed for military applications

Detection principlesDetection principles

CapacitiveCapacitive PiezoelectricPiezoelectricPiezoresistivePiezoresistiveOpticalOptical MicroflowMicroflowKnowles AcousticsSonionMEMSMEMSTechInfineonAkusticaMatsushitaApogeeHosidenVTT Electronics…

Phone-OrToshibaNASA

Microflown

© 2005• 8

4. Industry status of development Existing products

• 4 Companies are in production today:

• Knowles Acoustics (US):- In production since 2003- 2004 sales: 50 M units- Silicon microphone chip on PCB

with metallic lid

• SonionMems (DK):- Part of the Sonion Group (3000

persons, 114 MEuro sales in 2004)- Technology leader with volume

manufacturing capabilities- They are shipping sample in 08/2008

and volume is expected very soon- We expect product commercial release

in September-October 2005

- Phone-Or (IL)- Specific optical microphones

dedicated to security applications

- Microflown (NL)- Specific microphones for

measurements

• Many other are still at development stage

– Hosiden (Korea)– Akustica (US)– Apogee (US)– Infineon (D), – Best Sound

Electronics (KR) NHK STRL (JP)

– Innovation Technology Co. (CN)

– Merry ElectronecsCo,Ltd (Taiwan)

– JL World (JP)

SonionMEMS SiMic product for mobile applications

Knowles Acoustics SiSonic product with opened mettalic lead

© 2005• 9

1995

4. Industry status of development Product introduction schedule

2001 2004 20102007

Star

t of r

e sea

r ch

eff o

rts

1998

Fir s

t co

mm

erci

aliz

a tio

n 2003 - Knowles Acoustics2005 – SonionMEMS for

mobile phones

1997 - Infineon

2006 – MemsTech

2001 - Akustica

2003 - Apogee

1992

2007 – SonionMEMS for hearing aids applications

2006 – Akustica

1995 -SonionMEMS2002 - MemsTech

1992 -Knowles

2006 – Apogee

1994 - NCT

<1992 – Draper Lab

2006 – Infineon

2006 – … (confidential newcomer)

© 2005• 10

4. Industry status of development Current partnerships

Markets Partners Prod.GN ReSound (DK) 2006

BSE (Best Sound Electronics) (KR) Cell-Phone Samsung (KR) R&D in 2005 Capacitive

Prod since 2003

Innovative Technology (INN Acoustics) (CN) Cell Phone D in 2005 Capacitive

Microflown (NL) Measurement Microphone Prod Microflow

NHK (JP) Broadcast Panasonic Mobile Communication (JP) R&D in 2005 Capacitive

Toshiba Corporate R & D Center Auto Handset R&D in 2005 Optical

Prod in 10/05

No prod.

Neonode (SW)MEMSCAP (FR)

Siemens (D)Siemens Hearing (D)

Motorola’s TCG (USA)Kenwood (JP)

SonionKirk (DK)

Nokia (FI)

Techno

Infineon (D) Auto Handset, Hearing aid Capacitive?

VTT Information Technology (FI) Cell-Phone Capacitive

Akustica (USA) Cell-Phone, Hearing aid Capacitive

Knowles Acoustics (USA) Cell-Phone Capacitive

Phone-Or (IL) Auto Handset Optical

SonionMEMS (DK) Cell-Phone, Hearing aid Capacitive

© 2005• 11

5. Industry organization and trends

© 2005• 12

3. Silicon Microphone flow chart :from design to OEM integration

STEP STRUCTURE DESIGN

PROCESS DESIGN

DIE MANUFACTURING ASSEMBLY PACKAGING

and TESTS OEM ASSEMBLY

Resources required

MEMS and ASIC design expertise Electronic assembly line

OEM

Silicon Microphone

Final products: Mobile Phone, Hearing aids….

Players Design department Foundry Back End

Chip Wafer Dies

Acoustics expertise: design and electronics

Process knowledge and Manufacturing capability

Back-End and Test capability

Silicon microphone flow chart model

Chips assembly

MEMS Manufacturing processes definition and tests

Handling and soldering on PCB

Sensing element structure design

MEMS Foundry

ASIC design

ASIC manufacturing processes definition and tests

ASIC Foundry

Packaging

Tests Ship

ping

FIN

AL

PRO

DU

CT

© 2005• 13

3. Silicon Microphone flow chart :Business model comparison

• To that extend, three technological models ave been identified:

– SonionMEMS products are made from 3 silicon dies assembled together

• Each die comes from an different foundries (partners)• Dies are assembled at SonionMEMS site (proprietary

assembly process)

– Knowles Acoustics SiMicro:• ASIC and MEMS microphone comes from different foundries

(partners)• Dies are glued onto a PCB substrate. • Dies are connected to metallic PCB contacts using wire

bonding• Frame and metallic lid are fixed onto the PCB and the

connected dies

– MemsTech• ASIC and MEMS sensing element manufactured within

MemsTech• It is a hybrid microphone which is 1.4mm*4mm (die size is not

available) – The product size need to be checked when datasheets would be

available

ASIC chip

Substrate chipMicrophone chip

bond wire

microphonechip

lid with acoustical opening

backplate

contactcontact

glob top

PCB

adhesive

fram

e

© 2005• 14

5. Industry organization and trendsBusiness model analysis

• Knowles Acoustics was first in the market thanks to– Its basic technology

• Two chip component• Basic packaging metallic lead

– Its highly flexible business model• Fabless company• Two manucfacturing sources: Sony, Memscap

• Fabless business model is a general trend among MEMS microphone manufacturers– Subcontracted to MEMS foundries: Knowles, SonionMEMS– Subcontract to standard CMOS foundries:

• For ASIC: Knowles, SonionMEMS• For the whole device: Akustica, Apogee

• Integrated fabrication is reserved to big companies with SC fab– Infienon, Matsushita

© 2005• 15

6. Silicon Microphone technology overview

© 2005• 16

6. Silicon Microphone technology overviewMicrophone definition

• Definition:– A microphone is a device that converts sound

into an electrical signal

– In all microphones, sound waves (sound pressure) are translated into mechanical vibrations in a thin, flexible diaphragm. These sound vibrations are then converted into an electrical signal.

– Today the main microphone technology used is the ECM: Electret Condenser Microphone.

• In a condenser microphone, the diaphragm acts as one plate of a capacitor, and the distance changing vibrations produce changes in a voltage maintained across the capacitor plates

• An electret is a dielectric material that has been permanently electrically charged or polarised.

Microphones are basically a high speed pressure sensor

One of the smallest ECM from SMK Corporation (6 mm in diameter and 1.5 mm)

© 2005• 17

6. Silicon Microphone technology overviewAdvantages of Silicon Microphones vs. ECM

• Design advantages– Size reduction ideal for space-constrained designs

• Back plate and diaphragm in a MEMS microphone are approximately 10x smaller than those in the smallest ECM

• allows a packaged MEMS microphone to start at approximately the same size as the smallest ECM

• Potential to shrink much further as MEMS microphone technology matures

• Consumes less PCB space• Requires smaller height allowances

– Easy to integrate with new functions • Thus increasing the adaptability of the microphone for

different applications• First functions integrated is amplification of the acoustic

output• For example, several MEMS microphones include output

amplifiers capable of 20 dB gain in the signal transmitted to the codec

– The stronger output signal is less susceptible to noise. – Suitable when the acoustic input comes from a distance and is

weaker: » products such as camcorders and video phones for example

• This both simplifies design and saves board space.

Figure 2: Comparison of 4mm ECM vs. MEMS diaphragm

Figure 3: Size comparison of 4mm ECM vs. MEMS microphone

© 2005• 18

6. Silicon Microphone technology overviewSilicon MEMS Technology

• The silicon MEMS microphone is composed of the same parts than the ECM:– A membrane (few µm Silicon material thickness) which act as the flexible diaphragm– A back plate with is the reference of the capacitive sensing and is parallel to the membrane– Back plate let air from the 10µm cavity flow through its holes.

• It senses sound upon 5 main detection principle:– The vibration sound bend the membrane.– Membrane variation is detected using one of the 5 techniques:

• Capcitive• Piezo resistive• Piezo electric• Optical• Microflown

– The measured variation is then amplified and translated into electrical signal corresponding to the sound vibrations

Exmaple of NHK Capacitive Silicon Microphone

© 2005• 19

6. Silicon Microphone technology overviewDetection principle

• Three types of silicon microphones have been identified so far:– Capacitive detection is of high growth and interest today

• Dedicated to low cost and moderate performances devices: i.e. the replacement market of the ECM– Microflow detection is related to fine sound measurements

• Oriented toward measurement market– Optical detection is more military /security oriented

• This detection is very accurate and allow lot of noise reduction• It main feature is to be undetectable compared to other technologies• They are mainly developed for military applications

• This technology analysis will only cover the capacitive silicon microphones– 90 of developments and production are using capacitive detection principle

Detection principlesDetection principles

CapacitiveCapacitive PiezoelectricPiezoelectricPiezoresistivePiezoresistiveOpticalOptical MicroflowMicroflow

© 2005• 20

7. Silicon Microphones Manufacturing Challenges

© 2005• 21

7. Silicon Microphones Manufacturing Challenges Challenges in Manufacturing Processes

• General concepts in MEMS Manufacturing:

• Reduce number of process steps is the main goal in MEMS design– Cost of MEMS die is generally estimated using cost in $/step/mm²– Great cost advantage which is a key success factor

• MemsTech seems to have achieved an only 3 process step design• Matsushita has announced a 2 process steps

– Decreasing number of steps reduce the manufacturing complexity• Yield is expected to be higher

• Avoid costly processing technologies such as:– Dry etching– Wafer bonding– Sacrificial etching (because of its well-known risk of stiction)

© 2005• 22

7. Silicon Microphones Manufacturing Challenges Challenges in Technology Design

• The active region of the MEMS device is the gap between membrane (or diaphragm) and back plate

• The membrane has to – Measure the low pressure level (e.g. a sound pressure level of 100

dB -which corresponds to a pneumatic hammer- is equivalent to a pressure of 2 Pa).

– High dynamic measurement range from several Hz up to at least 10 kHz

– The two requirements mean that very thin diaphragms must be used(ex: NHK prototypes changes from 5µm thickness to 4µm)

• The gap must be – Of uniform thickness – As thin as possible to be more sensitive (i.e. NHK prototype

deceased their gap from 15µm to 10µm)

• Structure design has to be thought using has few as possible process steps:

– MEMS average process steps for a structure is 11– Die cost is directly link to number of steps– One process step correspond to a lithography step

• This is one of the most expensive manufacturing part:– Lithography equipments are costly – Lithography is usually the bottleneck of the fab in through put– Masks (pattern which are transferred onto the wafer) are expensive– One step = One mask

– For example MemsTech claims it managed to have a 4 step only process for its microphones

Membrane / Diaphragm

Air gap

NHK silicon microphone structure