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© 2010 by SYSTEM PLUS CONSULTING, all rights reserved. AKM AK8973S 1

9 rue Alfred Kastler - BP 10748 - 44307 Nantes Cedex 3 - France

Phone : +33 (0) 240 180 916 - email : [email protected] - website : www.systemplus.fr

September 2010 - Version 1

Written by: Romain FRAUX

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.

http://www.systemplus.fr/



Table of Contents

Glossary

1. Overview / Introduction……………………….…........…4

– Executive Summary

– Reverse Costing Methodology

2. AKM Company Profile …...……………....……...............6

– AKM Product line

– AK8973S Block Diagram

– AKM Business Model

3. Physical Analysis……………………….………......…...11

– Synthesis of the Physical Analysis

– Physical Analysis Methodology

– Package Characteristics & Markings

– Package X-Ray

– Device Structure

– ASIC – Dimensions

– ASIC – Pads Distribution Reconstitution

– ASIC – Block Functions

– ASIC – Markings

– ASIC – Bond Pads

– ASIC – Capacitors/Resistors

– ASIC – Hall Sensors

– CMOS Hall Sensor Principle

– Component Cross-Sections

– Physical Data Summary

– Process Characteristics

– AKM Electronic Compasses – Dies Comparison

4. Manufacturing Process Flow…………………………..….45

– Overview

– ASIC Process Flow

– Packaging Process Flow

– Description of the Wafer Fabrication Units

5. Cost Analysis……………………………………………..…..52

– Synthesis of the Cost Analysis

– Main Steps of Economic Analysis

– Supply Chain Analysis

– Yields Explanation

– Yields Hypotheses

– Front-End : Hypotheses

– Front-End Cost

– Back-End 0 : Probe Test Cost

– Die per wafer & Probe Test

– Back-End 0 : Packaging Hypotheses

– Back-End 0 : Packaging Cost

– Back-End 0 : Packaging Cost per Process Steps

– Back-End 0 : Dicing Cost

– Total Wafer Cost (Front-End + Back-End 0)

– Back-End 1 : Final Test & Calibration Cost

– AK8973S Cost (FE + BE 0 + BE 1)

6. Estimated Manufacturer Price Analysis ………………...72

– Definitions of Prices

– Manufacturers financial ratios

– Estimated Manufacturer Price

Conclusion ………………………………………………………76



Package Characteristics & Markings

• Package type: 15-pin WL-CSP, LGA

• Dimensions: 2.5mm x 2.5mm x 0.5mm

• Pin pitch: 0.5mm

• Marking:

8973

936H

Package Back view

Package Top view

Package Side view



The schematic diagram below is based on the observations made during this study and detailed in the

next slides.

Device Structure

ASIC with Aluminium

pads

Polyimide

dielectric

Magnetic

Concentrator Redistribution

copper layer

Epoxy resin

Copper pillar

Only 500µm of thickness with the bumps

SAC bumps



ASIC – Pad Distribution Reconstitution

ASIC with Pad Distribution Reconstituted

Magnetic

Concentrator

Redistribution

Layer (RDL)

CAD0

CAD1

VID

SDA

SCLTST1INTRSTN

VDDVSS

TST3

TST2



ASIC Overview

Hall Sensors – Optical View

Hall Sensors – Optical View

ASIC – Hall Sensors

• The Hall Sensor structure is

composed of 8 sensors.

•There are no Metal 3 layers on

the Hall Sensors area.

•The Hall sensors are created

with n-wells implantations in the

Silicon p-substrate.

Metal 1

Metal 2

Metal 3

Si

p-substrate

Hall sensor

Hall sensor



Principle of the Si-monolithic geomagnetic sensor. Left: A cross-sectional view of the focusing of

magnetic field lines into Si monolithic Hall sensors by the magnetic concentrator, length L and thickness

t. Right: A plan of the relative positions of the magnetic concentrator and Si monolithic Hall elements.(Courtesy of Asahi Kasei Microdevices)

CMOS Hall Sensor with IMC Principle

• The AKM electronic compass uses the integrated magnetic concentrator (IMC)

technology to measure and extrapolate magnetic field on 3 axis.

• A circular ferromagnetic concentrator bends magnetic fields into four CMOS Hall

sensors positioned at each 90° angle under the concentrator periphery. These sensors

can measure the magnetic field in the X and Y directions. By adding and subtracting

these measures, the magnetic field in the Z direction can be implemented.



Component Cross-Section (AA')

AA' Cross Section Overview

Cross-Sectional Plane AA'

Epoxy Resin

ASIC

SAC Bump

Magnetic

Concentrator

Copper Post



Cross-Sectional Plane DD'

Component Cross-Section (DD')

M2

M3

M1

ASIC Process detail – SEM View

ASIC Process detail – SEM View

•Revelation of Polysilicion and doped area

•Process details:

CMOS transistors with xxµm gate

length.

3 Metal Layers TiN/Al/TiN

Tungsten plugs

Passivation SiO2 + SiN



Packaging Process Flow (2/2)



Main steps of economic analysis

• We perform the economic analysis of the ASIC with the IC Purchaser software.

Probe Test Cost

Packaging Cost

Dicing Cost

ASIC Manufacturing Cost

Back-End 0

Back-End 1 Final Test Cost

Component Cost

Front-End


http://www.systemplus.fr/index.php?lang=us&page=icpurchaser.php


Front-End Cost

• The ASIC Manufacturing cost

ranges from $xx to $xx according

to yield variations.

•The main part of the Front-End

cost is due to the xxxx with xx%.

• The manufacturing yield ranges

from xx% to xx%.



Packaging Cost per Process Steps (2/2)

Packaging Step Cost Breakdown

Repassivation - Cleaning $1,10 0,7%

Repassivation - Measurement $0,66 0,4%

Repassivation - Polyimide Deposition (5.6µm) $7,19 4,7%

Repassivation - Pattern $0,88 0,6%

Repassivation - Cleaning $2,76 1,8%

Repassivation - Measurement $0,66 0,4%

UBM Barrier/Seed - TiN deposition $4,79 3,1%

UBM Barrier/Seed - Cu PVD deposition $2,95 1,9%

UBM Barrier/Seed - Reflow $0,90 0,6%

UBM Barrier/Seed - Cleaning $1,10 0,7%

UBM Barrier/Seed - Measurement $0,66 0,4%

Magnetic Concentrator - PR Deposition $3,85 2,5%

Magnetic Concentrator - Pattern $0,88 0,6%

Magnetic Concentrator - Cure thick resin $1,91 1,3%

Magnetic Concentrator - Cleaning $1,10 0,7%

Magnetic Concentrator - Measurement $0,66 0,4%

Magnetic Concentrator - Ni Deposition (16µm) $3,78 2,5%

Magnetic Concentrator - PR Removal $1,11 0,7%

Magnetic Concentrator - Cleaning $1,10 0,7%

Redistribution layer - PR Deposition $2,59 1,7%

Redistribution layer - Pattern $0,88 0,6%

Redistribution layer - Cure thick resin $1,91 1,3%

Redistribution layer - Cleaning $1,10 0,7%

Redistribution layer - Measurement $0,66 0,4%

Redistribution layer - Copper ECD 6µm $3,44 2,3%

Redistribution layer - PR Removal $1,11 0,7%

Redistribution layer - Cleaning $2,59 1,7%

Copper post - PR Deposition (Thick resin 50µm) $5,75 3,8%

Copper post - Pattern (Thick resin) $1,08 0,7%

Copper post - Cure thick resin $1,91 1,3%

Copper post - Cleaning $1,10 0,7%

Copper post - Measurement $0,66 0,4%

Copper post - Copper ECD 66µm $26,05 17,1%

Copper post - CMP $6,89 4,5%

Copper post - Cleaning (Thick resin) $11,02 7,2%

Copper post - PR Removal (Thick resin) $1,11 0,7%

Copper post - Measurement $0,66 0,4%

UBM etching - Copper etching (seed layer) $2,44 1,6%

UBM etching - TiN etching $2,59 1,7%

UBM etching - Cleaning $1,10 0,7%

UBM etching - Measurement $0,66 0,4%

Encapsulation layer - Epoxy deposition $9,73 6,4%

Encapsulation layer - Grinding $4,82 3,2%

Encapsulation layer - Cleaning $1,03 0,7%

Encapsulation layer - Measurement $0,66 0,4%

Encapsulation layer - Cu Etching $2,61 1,7%

Encapsulation layer - Cleaning $1,10 0,7%

Encapsulation layer - Measurement $0,66 0,4%

Additional BE - Backgrinding (300µm) $3,51 2,3%

Additional BE - Cleaning $1,10 0,7%

Additional BE - Laser Marking $4,63 3,0%

Additional BE - Cleaning $1,10 0,7%

Bumping - screenprinting $3,45 2,3%

Bumping - reflow $0,89 0,6%

Bumping - Cleaning $1,10 0,7%

Bumping - Measurement $0,66 0,4%

TOTAL $152,41

Packaging Steps Cost



AK8973S Component Cost (FE + BE 0 + BE 1)


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