Germanium thickness - I-Micronews

21 rue La Nouë Bras de Fer – 44200 Nantes - France
Phone : +33 (0) 240 180 916 - email : info@systemplus.fr - website : www.systemplus.fr
November 2012- Version 2
Written by: Sylvain HALLEREAU
DISCLAIMER : System Plus Consulting provides cost studies based on its knowledge of the manufacturing and selling prices of electronic components and systems. The given values are realistic
estimates which do not bind System Plus Consulting nor the manufacturers quoted in the report. System Plus Consulting is in no case responsible for the consequences related to the use which is
made of the contents of this report. The quoted trademarks are property of their owners.
© 2011 by SYSTEM PLUS CONSULTING, all rights reserved. InvenSense – MPU-9150 1

• 1. Overview / Introduction 3
– Executive Summary
– Reverse Costing Methodology
• 2. Company Profile 5
• 3. Physical Analysis 13
– Synthesis of the Physical Analysis
– Physical Analysis methodology
– Package characteristics & markings
– Package opening
– Package Opening : Dies Bonding
– Package Cross Section
– Invensense ASIC Marking
– Invensense ASIC Dimensions
– Invensense ASIC minimal dimensions
– Invensense ASIC Cross section
– Invensense ASIC Process Characteristics
– Invensense MEMS marking
– Invensense MEMS Opening
– Invensense MEMS Sensing Area
– Invensense MEMS Cap
– Invensense MEMS Process Characteristics
– Magnetometer marking
– Magnetometer Dimensions
– Magnetometer Cross Section
– Magnetometer Process Characteristics
• 4. Manufacturing Process Flow 84
– Global view
– Process Flow Accelerometer ASIC
– Process Flow MEMS Accelerometer
– Process Flow Magnetometer
Table of Contents
– Process Flow Packaging
– Description of the Wafer Fabrication Unit
• 5. Cost Analysis 102
– Synthesis of the cost analysis
– Methodology
– Hypothesis
– Yield Synthesis
– Invensense ASIC Wafer Cost
– Invensense ASIC Die Cost Data
– MEMS Accelerometer Wafer Cost
– MEMS Accelerometer cost per Steps
– MEMS Accelerometer Equipment cost
– MEMS Accelerometer Material cost
– MEMS Accelerometer Die Cost
– Magnetometer Wafer Cost
– Magnetometer cost per Steps
– Magnetometer Material cost
– Magnetometer Die Cost
– Back-End : Package Cost
– Back-End : Package Cost Per Steps
– Back-End : Package Material cost
– Back-End : Final Test
– MPU9150 Manufacturing Cost
– Cost Analysis Evolution over yield
• 6. Estimated Selling Price Analysis 148
– Supply Chain Analysis
– Estimated Selling Price
– Price Evolution according to the yield
• Glossary
• Contacts
© 2011 by SYSTEM PLUS CONSULTING, all rights reserved. InvenSense – MPU-9150 2

• Package type : LGA-24pins
• Dimensions : 4.00mm x 4.00mm x 1.00mm
• Pin pitch : 0.5mm
4.00mm
Package Side view
Package Characteristics & Markings
1.00mm
4.00mm
Package Top view
Package Back view
4.00mm
© 2011 by SYSTEM PLUS CONSULTING, all rights reserved. InvenSense – MPU-9150 3
0.50mm

ASIC
MEMS Accelerometer + Gyroscope
Magnetometer
Package Opening : Optical View
� Package opening reveals two chips bonded to
the package susbstrate by wire bonding
process.
Package Opening :Main Parts
Package Opening : Optical view
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ASIC
MEMS Accelerometer + Gyroscope
Magnetic concentrator
Magnetometer
Y-axis
magnetometer

xxµm
Magnetometer
Cap
Sensor
ASIC
xxµm
xxµm
Package cross-section : SEM view
Package Cross Section
xxµm
Solder mask
LGA Substrate
Copper
Solder
LGA substrate : SEM view
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xxµm
xxµm
xxµm
xxµm
xxµm
xxµm

X Axis Gyroscope SEM view
Bar linkage
Bar linkage
Interdigitated electrodes SEM View
MEMS Sensor – X-Axis Gyro
Proof mass ASIC Cavity
Capacitive
electrodes
X-Axis Gyro– Tilt View
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Package Cross Section
LGA 24 package
Package cross-section : Optical view
Magnetic
concentrator
Magnetometer
MEMS inertiel
Cap
Sensor
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ASIC
LGA24 substrate
2 layers

Oxide
Germanium
Cap
Sensor
ASIC
The Cap wafer and Sensor
wafer are bonded together
using an a fusion bonding
process.
Component Cross-Section AA’
AA' Cross Section Overview
Oxide
Germanium
Saw cut
sign
The ASIC wafer and
Sensor wafer are bonded
together using an
Aluminum/Germanium
Eutectic bonding process.
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Cross Section SEM View
Cap
Oxide
Sensor
Bonding Cap & Sensor
Component Cross-Section AA’
Sensor
Bonding ASIC & Sensor
� Total oxide thickness ~ 2µm
� Germanium thickness ~0.25µm
Germanium
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ASIC
Germanium connects electrically the MEMS
Sensor and ASIC Aluminum metallization.

AK8975 Overview
Metal 2
Metal 1
Hall captor details – Optical View
Metal 3
AK8975 – Hall Sensors
Hall sensor
Si
p-substrate
Hall captor – Optical View
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Die Cost
Low Yield Medium Yield High Yield
Cost Breakdown Cost Breakdown Cost Breakdown
FE : ASIC Cost 19.4% 22.7% 26.2%
FE : MEMS Cost 10.7% 11.0% 11.2%
FE : ASIC/MEMS Assembly Cost 8.5% 7.1% 5.4%
Foundry Overhead Cost 35.7% 37.6% 39.5%
BE 0 : Probe Test + Dicing Cost 1.8% 2.1% 2.5%
BE 0 : Yield losses 23.8% 19.5% 15.2%
Foundry Overhead
Cost
48%
Die Cost 100% 100% 100%
Die Cost Breakdown (Medium Yields)
FE : ASIC/MEMS
Assembly Cost
9%
FE : ASIC Cost
29%
FE : MEMS Cost
14%
• The final die cost ranges from $xxx
to $xxx according to yield
variations.
• The back-end 0 cost (probe test and
dicing) represents 2% of the cost of
the die.
• The yield losses costs due to probe
and dicing represents 20% of the
total manufacturing cost.
– The die cost includes the rejects at
probe test and dicing.
– The yield losses represents the
defective dies which are rejected.
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Conclusion
• Reverse costing analysis represents the best cost/price evaluation given the publically
available data, completed with industry expert estimates.
• Given the hypothesis presented in this analysis the major sources of correction would lead to
a +/- 10% correction on the manufacturing cost (if all parameters are cumulated)
• IC +/- 8%
• MEMS +/- 5%
• Packaging +/- 10%
• Test +/- 20%
• These results are open for discussion. We can re-evaluate this component with your
information. Please contact us:
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