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INDUSTRIAL TRAINING REPORT AT ONSEMICONDUCTOR (SCG) INDUSTRIES MALAYSIA SDN BHD BY, LEE KOK YEW (EE081554) DEPARTMENT OF ELECTRICAL & COMMUNICATION ENGINEERING UNIVERSITI TENAGA NASIONAL START DATE: 11 APRIL 2011 END DATE: 1 JULY 2011 DURATION: 12 WEEKS

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INDUSTRIAL TRAINING REPORT AT ONSEMICONDUCTOR (SCG) INDUSTRIES MALAYSIA SDN BHD

BY,

LEE KOK YEW (EE081554)

DEPARTMENT OF ELECTRICAL & COMMUNICATION ENGINEERING

UNIVERSITI TENAGA NASIONALSTART DATE: 11 APRIL 2011

END DATE: 1 JULY 2011DURATION: 12 WEEKS

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SCG INDUSTRIES MALAYSIA SDN BHDLOT 122, SENAWANG INDUSTRIAL ESTATE,

70450 SEREMBAN, NEGAERI SEMBILAN

INDUSTRIAL TRAINING REPORTS

NAME : LEE KOK YEWID : EE081554IC NO. : 890725-05-5541COURSE : ELECTRICAL &

COMMUNICATIONS ENGINEERING

UNIVERSITI : UNIVERSITI TENAGA NASIONALHOST LECTURER: DR. KANNAN M. MUNISAMYCOMPANY : ON SEMICONDUCTORDEPARTMENT : POWER PRODUCT DIVISION

INTEGRATED CIRCUITSUPERVISOR : YAP SHONG LAEYPERIOD : 11 APRIL 2011 – 1 JULY 2011

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ACKNOWLEDGEMENT

I would like to express my gratefulness to participate of the following

organization or any individuals who contribute in my industrial training program and the

case study project. During my 12 weeks of training, I have been assign under Mr Yap

Shong Laey which is my supervisor during the time. He is the production head of Power

IC department in ON Semiconductor. I want take this opportunity to thank my supervisor

for his guidance throughout the whole industrial training. Besides that, I would also like

to thank Mr Chow Yi Heng and Mr Chaw Wing Onn. Although they are not my

supervisor, but they are willing to teach and guide me in my training program.

A special thanks also to all the profession staff in ON Semiconductor who

following this below:

Mr Lee Yeu Wen, Manufacturing Engineer

Ms Koh Siew Ting, Process Engineer

Mr Ong Hao Yii, Process Engineer

Mr Azharsyah, Process Engineer

Mr Nor Halim, Process Engineer

Besides that, I also want take this opportunity to thank Mr. Kannan M. Munisamy

which are my visiting lecturer who really doing hard come all the way from UNITEN to

pay a visit in order to understand my training condition and my work over ON

Semiconductor.

Last but not least, I would like to send my special thanks to every personnel staff

in ON Semiconductor who give their support and guidance throughout my internship

period especially staffs and operators from Power Product Division-Integrated Circuit

(PPD-IC) and PPD-Wire.

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CONTENTS

1.0 ACKNOWLEDGEMENT

2.0 INTRODUCTION TO ON SEMICONDUCTOR

2.1 HISTORY OF MOTOROLA SPS

2.2 HISTORY OF ON SEMICONDUCTOR MALAYSIA

2.3 CHRONOLOGY OF ON SEMICONDUCTOR SEREMBAN

2.4 VISION & MISSION

3.0 OVERVIEW OF ON SEMICONDUCTOR SEREMBAN

3.1 DEPARTMENT CHART ON SEMICONDUCTOR SEREMBAN

3.2 COMPANY ORGANIZATION CHART

3.3 ORGANIZATION CHART FOR POWER IC DEPARTMENT

4.0 PROCESS FLOW IN POWER IC

4.1 FRONT END

4.1.1 WAFER MOUNT

4.1.2 WAFER SAW AND WASH

4.1.3 DIE BOND

4.1.4 WIRE BOND / CLIP BOND

4.2 BACK END

4.2.1 MOLD

4.2.2 PLATING

4.3 FINAL TEST

4.3.1 TRIM / FORM (SINGULATION)

4.3.2 ELECTRICAL TEST

4.3.3 MARKING

4.3.4 PACKING

4.4 PRODUCT OF POWER-IC

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5.0 TRAINING ACTIVITIES

5.1 FRONT END

5.2 BACK END

5.2.1 DELAM (SAT ANALYSIS)

5.2.2 WIRE SWEEP ANALYSIS (X-RAY)

5.2.3 CROSS-SECTIONING

5.3 FINAL TEST

5.3.1 LOW POWER MICROSCOPE

5.3.2 HIGH POWER MICROSCOPE

6.0 PROJECT

7.0 PROBLEM

8.0 REFERENCES

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2.0 INTRODUCTION TO ON SEMICONDUCTOR

ON Semiconductor is one of the world largest suppliers of performance chips for

power management in electronics systems. ON Semiconductor produces power and

signal management, logic, discrete and customs devices for automotive, communications,

computing, consumer, industrial, LED lighting, medical, military or aerospace and power

applications. ON Semiconductor is a world-renowned company today with

manufacturing facilities standing firmly in all parts of the world. Subsidiary of Texas

Pacific Group, ON Semiconductor’s headquarters is in Phoenix, Arizona(USA) and her

sibling in Guadalajara, Mexico; Pestany, Slovak Republic; Roznov, Chech Republic;

Toulouse, France; Seremban, Malaysia; Leshan, China and Aizu, Japan. It also has sales

offices throughout the world. ON Semiconductor’s internal manufacturing base is global,

with 8 manufacturing sites including the first wafer FAB in western China dedicated to

building state of the art power management products. This diversity and distributed

matrix of sources reduces supply side risk and enables cost effective manufacturing and

delivery of our products anywhere in the world.

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2.1 HISTORY OF MOTOROLA SPS

ON Semiconductor ( Formerly a Division of Motorola). ON Semiconductor is just

beginning but its rooted back to its former parent, Motorola indefinitely. Motorola was

established by two brother during the late 20’s, Paul V Galvin and Joseph E Galvin. In

September 25th ,1928, both founder of Motorola bought over battery eliminator business

from Stewart Storage, a company based in Chicago which at that time faces near

bankruptcy. They incorporated the Galvin manufacturing Corporation until it was change

to Motorola. From the day they own the company until the 1930 there were no innovation

nor invention produced. Hence the company’s early battery eliminator, private-label

home radios and pioneering auto radios had no distinctive trademark other than the

corporate name. In 1930, Paul Galvin conceived the name Motorola to convey the

excitement new idea of music in motion for the company’s auto radios, the first mass

production. This new trademark so widely known took Motorola as its corporate name in

1947. The first Motorola trademark registered in1930 had the appearance of being hand

written with a lightning bolt crossing the T. Other variations were used over the years,

emblazoned on highway signs, product billboards , packaging and print advertising until

the modern design is introduced .

2.2 HISTORY OF ON SEMICONDUCTOR MALAYSIA

ON Semiconductor Malaysia, managed and operated wholly by Malaysians, is the

discrete semiconductor power house. ON Semiconductor Malaysia, has its beginning in

1979 with the incorporation of Motorola Semiconductor Sdn.Bhd (MSSB). In 1987, it

established the second facility with the incorporation of Motorola Electronics Sdn.Bhd

( MESB). It went on to achieve a historic first for the nation with the establishment of

Integrated Surface-mount Manufacturing Facility (ISMF).This first such facility in the

country strategically aligns wafer fabrication, assembly and testing under one roof,

producing discrete transistors, biased resistor-transistors and switching diodes in world

class cycle time. From two world-class manufacturing facilities in Senawang Industrial

Estate, Seremban, Malaysia. ON SEMICONDUCTOR is providing Original Equipment

Manufacturing (OEMs) worldwide with a broad range of discrete and analog products in

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Surface Mount and Power packages such as power and signal management, logic,

discrete and customs devices for automotive, communications, computing, consumer,

industrial, LED lighting, medical, military or aerospace and power applications. The

mission of ON Semiconductor is to become “The Premier Power Solutions Provider”.

And the vision is to enable ON Semiconductor to dominate Power and Data Management

segments by providing Advanced Packaging solutions with competitive cost through

operational excellence.

ON semiconductors Malaysia has 2 plants which both located in Seremban. Site 1

is the main manufacturing line for ON Semiconductor Malaysia branch. Site 2 is mainly

wafer fabrication and laboratory work.

2.3 CHRONOLOGY OF ON SEMICONDUCTOR SEREMBAN

1979- 15 Motorola Kuala Lumpur personnel relocated to start-up 12,000 sq. ft.

Facility purchased from Spraque.First product was

Silicon Power Metal  (SPM).

1981- Added 100,000 sq. feet building

1982- Purchased adjacent factory with additional 28,000 sq. feet

1983- Started Test Operation for Standard Logic (14/16/20 LD PDIP) & discretes

(SOT23)

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SITE 1 – MANUFACTURING PLANT SEREMBAN, MALAYSIA

SITE 2 – WAFER FABRICATION PLANT SEREMBAN, MALAYSIA

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1984- Held the 1st Service Recognition Award for pioneer employees

1985- CEO Award of Excellence in Quality, Productivity & Delivery of IC 14/16 ld

D.I.P.

1986- Consolidated Discrete Assy/Test & moved out IC operation.

1987- Build ISMF (integrated Semiconductor Manufacturing Facility), Malaysia's

first Wafer Fabrication Plant.

1988- ISMF officially opened by Minister of Trade & Industry.

1990- Won Gold Award in Corporate first TCS Showcase.

Won SPS Patent of the Year Award.

1991- Motorola Malaysia won Prime Minister’s National Quality Award.

Presented 11 technical papers in Internecine. Judged best in 5 out of 8 categories,

also won Best Paper Overall Award.

Established Product Engineering organization.

1992- Provided key management and technical support to Motorola- Philips JV

(SMP) start-up.

1993- Expanded Wafer Fabrication operation to include Ion Implantation process.

1994- Obtained ISO 9002 certification.

Provided management team to start-up Motorola’s most successful JV in China.

1995- Added 43000 sq. feet at ISMF, MESB Added 83,000 sq. feet at North Wing,

MSSB.

1996- Established Technical Operation organization.

Won Malaysia’s Hibiscus Award for Exceptional Achievement in Environmental

Performance.

1997- Developed & introduced new surface mount packages (TSOP6 & Power mite).

Certified QS9000 - The first SCG plant.

Accounted for 11 out of 28 patents filed from all SPS Asian manufacturing sites.

ISMF engineers designed the 1st die- integrated dual inductive load driver that

replaces three SOT23 with one.

1998- Successfully transferred 500 devices from BP5 to ISMF fab.

Accounted for 77% patent pursues (33 out of 43)for Asian manufacturing sites.

RF Linear Modules won ‘Best Overall Supplier of the Year’ Award from Philips

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Broadband and ‘Component Supplier of the Year’ Award from C-COR.

TPM was officially launched on September 9 at 9:09 am.

1999- The first Analog Micro-8device was qualified.

Successfully executed Analog SOT23L transfer from Aizu.

Successfully transferred Analog IC-DPAKfrom KLM.

Won the 4th Gold Award from Malaysian Society of Safety & Health(MSOSH).

Motorola Corporation awarded ON Semiconductor Sbn "The Excellence In EHS

Performance".

On August 5 1999, SCG becomes ON Semiconductor.

Official Launching of ON Semi Seremban by US Ambassador to Malaysia.

Awarded the 1st. ON Semiconductor corporate quality Award for "Excellence in

Continous Quality Improvement for SOT23".

2000- Became a Public Listed Company on April 28th.

Won the 5th Gold Award from Malaysian Society of Safety & Health (MSOSH).

DaimlerChrysler Corp Gold Award.

RF products transferred to Motorola KLM after 18 years in SBN.

Site 1 Reconfiguration for more production space.

Certified for QS90003rd Edition.

New Products Introduction – SC88/A, SC82AB.

Komala Ramasamy awarded Model Female Employee of the Year for Malaysia

by Human Resource Ministry.

11 Patentsfiled.

2001- Rated #1 in Supplier Quality by Seagate.

Certified for QS9000 3rd Edition (including Package Design Control).

Certified for TS16949 : 1999 (1st semiconductor firm in the industry).

Introduced Chip FET package (half footprint of TSOP6).

JIPM TPM Excellence Award - First Category (1st & only site in ON Semi).

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2.4 VISION & MISSION

I. Vision

-To become “The Premier Power Solution Provider”

II. Mission

-Enable ON Semiconductor to dominate Power and Data Management segments by

providing Advanced Packaging solutions with competitive cost through operational

excellence.

III. Quality Policy

-We will exceed Customer Expectations with our Superior Products and Services.

IV. Quality Statement

-Every ON employee is personally responsible for ensuring the highest Quality in the

products and services delivered to internal and external customer. Continuous

improvement in the quality of our processes, products and services is fundamental to the

achievement of customer satisfaction. Original Equipment Manufacturing (OEMs)

worldwide with a broad range of discrete and analog products in Surface Mount and

Power packages. Nowadays, ON Semiconductor Seremban has almost 1900 employees to

manage and operate the company.

V. Objective

Enables energy efficient solutions for a greener world

Provides a broad array of products and solutions

Helps customers solve their unique design challenges

Operates a world-class, value added supply chain

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ON SEMICONDUCTOR(SITE 2)

WAFER FRIBRICATION LABORATORY WORK

ON SEMICONDUCTOR(SITE 1)

PPD (POWER PRODUCT DIVISION) SOSM (SMALL OUTLINESURFACE-MOUNT)

PPD-IC(POWER PRODUCT DIVISION- INTEGRATED CIRCUIT)

PPD-WIRE(POWER PRODUCT DIVISION-WIRE)

PPD-CBSM(POWER PRODUCT DIVISION- CLIP BOND SURFACE-MOUNT)SOSM (SMALL OUTFIT SURFACE-MOUNT)QFN

(QUAD FLAT NO LEAD)

3.0 OVERVIEW OF ON SEMICONDUCTOR SEREMBAN

3.1 DEPARTMENT CHART ON SEMICONDUCTOR SEREMBAN

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3.2 COMPANY ORGANIZATION CHART

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Mohd Tarmizi SongOperations ManagerPPD/CBSM

Firdaus BadarudinProcess Engineer

Yap Shong LaeyManufacturing Equipment Engineer

Ong Hao YiiProcess Engineer

Koh Siew TingProcess Engineer

Sofia SulaimanQA/QC Engineer

Gan Chin SernProcess Engineer

Kam Mei SangManufacturing Equipment Engineer

Ng Then WaiManufacturing Engineer

Chaw Wing OnnManufacturing Engineer

Chong Kian HowEquipment Engineer

Lee Kok YewTrainee

Lee Chai PicTrainee

3.3 ORGANIZATION CHART FOR POWER IC DEPARTMENT

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4.0 PROCESS FLOW IN POWER IC

Throughout my 12 weeks of internship program, I had been placed in Power

Product Division – Integrated Circuit (PPD-IC) production line. My supervisor is Yap

Shong Laey. He is the head of manufacturing PPD-IC line. My given tasks are mostly

covered from front end, back end and final test.

In the production line, they are a total of 9 important steps required to produce a

unit. The first step will be wafer fabrication in Site 2. In this step, the chip or IC will be

mounting in a wafer that is ready to be shift out to Site 1 for production purpose. Second

step will be wafer saw and wash. The wafer will be mount by Mylar using ring and send

for wafer saw. Next, wafers will be send to the die bond machine. The chip or IC will be

place to the lead frame by the handler. After that, the lead frame will be move to next

process which is the wire bond or clip bond. There are 2 types of wires which are

commonly used, gold wire and copper wire. Size of wire are depends on type of products

that process. The fifth step will be the molding process. The lead frame that had already

connected with wire will send to back end for molding purpose. After molding, units are

then send for plating. The molded lead frame will be coat with a thin layer of chemical

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Frontend

Mounting

Saw

Die bond

Wire bond

Backend

Molding

Plating

FOI (Final Outgoing Inspection)

Final test

Trim and form

Testing and marking

Packing

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material for anti rust purpose. The seventh step will be the trim and form, molded strip

will be cut into single unit and ready send for testing purpose. In the final test session,

unit will run through a sort of test like isolation test, high temp and low temp test, QA test

and many more. Unit that successful run through all the test will be send for marking and

ready for packing. The entire unit will be put in a tube or a reel. After packing, products

are then ready to deliver to customer.

4.1 Front End

4.1.1 Wafer Mount

Wafers are mounted on a Mylar tape that adheres to the back of the wafer. The

mounting tape provides support for handling during wafer saw and the dies attach

process. The qualities that will be control are broken wafer check, scratches and bubbles.

4.1.2 Wafer Saw and Wash

This process will cut the individual die from the wafer leaving the die on the

Mylar tape. After sawn, the wafer will be wash to remove silicon debris. The qualities

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that will be control are die chip or crack, kerfs width and scribe defects.

4.1.3 Die Bond

This process provides mechanical support to the silicon die and electrical

connection between die to lead frame. The qualities that will be control are die shear and

bond line thickness.

4.1.4 Wire Bond / Clip Bond

This process provides copper / gold wire interconnection between silicon die pad

and lead frame lead/post. The qualities that will be control are ball shear and wire pull.

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Lead Frame: TO220 based material TO220 with die on the lead frame

Copper Wire / Gold Wire as connection wire between the die and

the post/flag

Source pad

Gate pad

Clip

SO8 Flat Lead

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4.2 Back End

4.2.1 Mold

Mold compound was used to protect the device mechanically and

environmentally. Transfer molding is used to encapsulate most plastic packages. The

qualities that will be control are wire sweep check, package offset and mismatch check.

4.2.2 Plating

This process allows for the

mechanical and electrical connection between the package and the printed circuit board.

Leadframe based packages most commonly use tin-lead solder plating as the final lead

finish. Pb-free packages use pure Sn as final lead finish. The qualities that will be control

are solder thickness and composition.

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TO220: Before Molding TO220: After Molding

Molding Machine: Lauffer

TO220: Before Plating

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4.3 Final Test

4.3.1 Trim / Form (singulation)

This is process where the individual leads of the leadframe are separated from the

leadframe strip. For manual trim and form, the lead are cut and formed mechanically to

the specified shape with a single punch. For auto trim and form, individual units are

singulated from the leadframe strip through progressive trim and form. The quality that

will be control is lead dimensions.

4.3.2 Electrical Test

These processes continue after assembly process. This is electrical test where to

ensure units are meeting electrical specification before shipping. The qualities that will be

control are bin sort check and correlation.

4.3.3 Marking

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TO220: Before Trim TO220: After Trim

Trim / Form machine: Micron

RAW UNIT: TO220

TESTER TEST HANDLER

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Corporate and product identification was place on a packaged device. This

marking allows for product differentiation. After test, only good units will be mark by

using laser method. The quality that will be control is marking verification.

4.3.4 Packing

This process is final packaging of product prior shipping to customers. The

quality that will be control is peel force check. The good unit will be pack in either tube

or tape and reel.

After that, the tube or reel filled with unit will be packed in a box. The box will be placed

in a pallet and ready to be shift out to customer.

4.4 Product of Power IC (PPD-IC)

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5.0 Training Activities

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Product of PPD IC

IC TO220

ICDPAK

ICD2PAK

Auto Thyristor

Iso Thyristor

ICD2PAK EG

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In ON Semiconductor, I was placed under Mr. Yap Shong Laey. He is a

equipment engineer of Power-IC. He is also the manufacturing head of the production

line. My practical work in ON Semiconductor is more related with the whole production

line which covered front-end, back-end and final test.

5.1 Front End

In the front-end, there were few things I have done during my internship period.

Firstly is wire pull. Wire Pull Testing (WPT) is one of several available time-zero tests

for wire bond strength and quality.  It consists of applying an upward force under the

wire to be tested, effectively pulling the wire away from the die. Wire pull testing

requires special equipment commonly referred to as a wire pull tester, which consists of

two major parts: 1) a mechanism for applying the upward pulling force on the wire using

a tool known as a pull hook; and 2) a calibrated instrument for measuring the force at

which the wire eventually breaks.  The wire pull tester measures the pulling force at

which the wire or bond fails. The measured force is then recorded in grams-force. Aside

from the bond strength reading, the operator must also record the bond failure mode.

Failure mode in this context refers to one of the following: 1) first bond (ball bond)

lifting; 2) neck break; 3) midspan wire break; 4) heel break; and 5) second bond (wedge

bond) lifting. First or second bond lifting is unacceptable and should prompt the process

owner to investigate why such a failure mode occurred.

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Photos of a wire pull tester stage (left) and a pull hook (right)

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Besides that, I have also leant concept of 5S in the front-end production line. 5S is

the name of a workplace organization methodology that uses a list if five Japanese words

which are seiri (sorting), seiton (straightening or setting in order), seiso (sweeping or

chinning or cleanliness), seiketsu (standardizing) and shitsuke (self discipline). Originary,

the machine and equipment in front-end was not arrange in order. I was assign to do so.

By doing that, I needed to do wire and pipe management which mean I need to use a

bracket or a plastic pipe to put all the wire all together so that it look nicer and not messy.

If the wire or cable is not arranged nicely and in order, it will cause accident to the

operator or staff that working in the production line. So in conclude, 5S concept is very

important for every company smoothly in the production line.

I also leant how to program a wire-bond machine to run the wire bond process.

This was learnt from a equipment engineer in the front-end. It consists a sort of steps to

teach the machine run wire-bond process. The machine that I have been teach is

shinkawa and ASM which is a Japanese machine.

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Wire and cable that is not arrange nicely

Wire Bond Process

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5.2 Back-End

In the back-end of the production line, usually trainee will be assign to do

DELAM or Wire Sweep for the molded strip. This usually is done when there is a major

breakdown for the molding machine. During a break down or shut down for the machine,

the production will stop. There will be an air gap that will cause in between the

DAMBAR and the MOLD. Once the machine is run again, the air gap will occur inside

the molded strip. This will cause the unit in the strip contains a layer of air gap. This air

gap will cause the heat inside the IC can’t be throw out by the heat sink. This will

damage the IC and will affect the performance of the unit.

5.2.1 DELAM (SAT Analysis)

SAT ANALYSIS

SAT (Scanning Acoustic Topography) analysis is the transmission and reception of

ultrasonic waves in DI (diluted) water media.

What are Ultrasonic Waves?

Ultrasonic waves refer to sound waves above 20 kHz (not audible to the human ear)

Characteristics of Ultrasonic Waves

1. Freely propagate through liquids and solids

2. Reflect at boundaries of internal flaws and change of material

3. Capable of being focused, straight transmission

4. Suitable for Real-Time processing

5. Harmless to the human body

6. Non-destructive to material

Detectable Defects

1. Delamination

2. Package Crack

3. Die Crack

4. Void

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5. Die Tilt

When is SAT testing necessary for qualification?

1. New packages

2. New assembly sites

3. Assembly site BOM changes (mold compound, die attach, lead frame)

4. Fab backmetal changes (high power dissipation products)

5. Fab passivation or die coat changes

6. New products in qualified packages if the die size is 1.15X or greater than the

largest previously qualified die size

What is the criterion for

passing SAT?

1. Zero delamination over

the surface of the die in a

clearly defined region.

Scattered “points” of

phase inversion are

acceptable.

2. Lead fingers cannot be 100% delaminated, including the non-wirebonded area.

3. Wirebond post cannot be 100% delaminated.

4. Zero delamination under the surface of the die in the die attaches material (high

power dissipation products only).

5. Zero delamination in the flag area surrounding the die for products that utilize a

down-bond process (wires bonded directly to the flag).

6. Delamination from the edge of the package cannot extend into the inner locking

feature of the package (e.g. V-groove).

For the last 4 weeks I have done many SAT analysis which specialize to detect

delamination in a package.

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SAT MACHINE

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Delamination

Delamination is the disbonding between two surfaces that are supposed to be attached. It

is important effects on the semiconductor package have emerged with improvements in

its detection. Delamination can occur between the molding compound and any of the

following: the die surface, the die paddle surface, the lead frame surface, and the die

attach material. Delamination between the molding compound and any of these can lead

to failure. Failure mechanisms that can result from die surface delamination include 'first

bond' lifting, wire necking, cratering, and intermetallic failures. Die paddle/lead frame

delamination, on the other hand, can cause 'second bond' lifting, heel cracking, and even

broken wires. Lead frame delamination can also lead to internal package cracking that

can allow conductive paths to form, which can result in current leakages. Corrosion is

also possible if the delamination reaches the package external, creating a path for

contaminants and moisture to enter the package. Cracks in the die passivation can also

result from die surface delamination after temperature cycling. Delamination can also

lead to package cracking during solder reflow.

Plastic package delamination is generally caused by:

1. non-optimized molding parameters

2. excessive temperature gradient across the mold die

3. inferior encapsulation material properties

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LID SEAL VOIDS DELAMINATION

DIE CRACK BGA DIE ATTACH

EXAMPLES FOR VOID PACKAGE

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How does SAT process work?

Ultrasound

• A transducer produces a high frequency sound wave which interacts with the

sample.

• High frequency sound waves cannot propagate through air.

• Couplant- A material used to carry the high frequency sound waves.

• Water is the most common couplant for immersion testing.

Inspection Modes

• Pulse Echo

• Through Transmission

Sound Reflection

Whenever a sudden change in acoustic

impedance is encountered, like at a material boundary, a portion of sound is

reflected and the remainder propagates through the boundary. By measuring the

reflected ultrasound can provide amplitude information, polarity information and

time information. There are 3 kinds of acoustics scans which differentiate to ABC.

A-Scan- The raw ultrasonic data. It is the

received RF signal from a single point (x,y).

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H2OTransducer

Receive

Connector

Backing

Material

(Damping)

Transducer Element (Piezo Electric Crystal, generates ultrasound)

Thicker transducer element producesLOWER FREQUENCY ultrasound.

Acoustic Lens(Focuses ultrasound)

Input pulse & output RF waveform

Transducers convert electrical energy to sound and sound back to electrical energy.

Transducers convert electrical energy to sound and sound back to electrical energy.

Thinner transducer element producesHIGHER FREQUENCY ultrasound.

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B-Scan- A line of A-scans. (Vertical cross-section)

C-Scan-Data from a specified depth over the entire scan area. (Horizontal cross-section.

Inspection modes

Pulse-Echo - One Transducer

• Ultrasound reflected from the sample is used.

• Can determine which interface is delaminated.

• Requires scanning from both sides to inspect all interfaces.

• Provides images with high degree of spatial detail.

• Peak Amplitude, Time of Flight (TOF) and Phase Inversion measurement

Through Transmission - Two Transducers

• Ultrasound transmitted through the sample is used.

• One Scan reveals delamination at all interfaces.

• No way to determine which interface is delaminated.

• Less spatial resolution than pulse-echo.

• Commonly used to verify pulse-echo results.

Digital Oscilloscope Waveform

Report done by,Lee Kok Yew Page 28

Pulse-Echo

Transmit&

Receive

Through Transmission

Transmit

Receive

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Gates are used to collect information at desired interfaces within the sample.

• The gate is placed over the signal or signals of interest.

• The absolute value of the highest amplitude signal which breaks the gate threshold within the gated region is recorded. (Figure 1)

• If no signal breaks the gate threshold no data is recorded. (Figure 2)

• Signal amplitude can be increased or decreased by adjusting gain.

In conclude, we use SAT analysis to perform checking on the unit whether there are air

gap occur in the unit. Air gap can cause the unit to run malfunction and will lead to the

system failure. So SAT scanning is a important scan for every electronic devices.

5.2.2 Wire Sweep Analysis (X-RAY)

Report done by,Lee Kok Yew Page 29

Initial pulse 2nd

Echo3rd Echo

Multiple Echoes

1st Echo

The 1st set of echoes is the area of interest, gate placement will be on this group.

Highest Amplitude signal

No data recorded

Gate Threshold

1

2

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A wire sweep analysis is used to predict the deformation of the bonding wires

within the cavity. It is run as part of the microchip encapsulation molding process. It is

used to calculate the deformation of the bonding wires (connecting the chip to the lead

frame) that occurs during encapsulation. This calculation enables you to improve the

mold design and process conditions to

prevent wire-sweep from occurring

during encapsulation. The sweep

deflection of wire bond caused by

compound flow during the transfer

molding process can seriously result in

wire crossover and shorting.

This is an example of a wire sweep analysis. Beside is

a sample image that taken from the X-RAY scope.

The tiny wire is connected the die and the post of the

unit. In this analysis, we need to determine the

percentage of wire sagging that were cause during the

molding process. The lesser the percentage of wire

sagging is better.

5.2.3 Cross-Sectioning

Cross-sectioning is a failure analysis technique for mechanically exposing a plane

of interest in a die or package for further analysis or inspection. It usually consists of

sawing, grinding and polishing, until the plane of interest is ready for optical or electron

microscopy. Observation in cross-section provides a wealth of information about the IC

device such as layer thicknesses, layer structures, and the grain sizes of various crystals in

Report done by,Lee Kok Yew Page 30

A simple X-Ray Machine Model

Example of Wire Sweep

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the layers. The first step in cross sectioning is mounting where it will provide

convenience in handling specimens of difficult shape or sizes during the subsequent steps

during metallographic preparation and examination. Material used is epoxy and hardener.

The mixture of resin and hardener will cast onto the specimen in the mould and leave the

mixture to cure normally at room temperature. Secondly is grinding, the purpose of

grinding is to eliminate gross and plastic deformation due to sectioning. Coarse grinding

is done using abrasive paper (silicone carbide paper) starting with 240 mesh, 400 mesh

whilst fine grinding is using 600 and 800 mesh. The purpose of polishing is to eliminate

the effect of deformation occur during grinding. Thirdly is polishing. Polishing machine

consist of soft cloth attached on rotation wheel. Very fine abrasive such as diamond

together with lubricant are applied on the cloth. Common diamond sizes are 6, 3 and 1

micron. This step is needed to be done until no scratch will appear under the microscope.

Cross section consists of 4 simple steps which is

1. SAMPLE MOUNTING

2. GRINDING

3. POLISHING

4. INSPECTION

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SAMPLE MOUNTING

Sample mounting is take the unit that needed to be grind or inspection purpose to make it

become a sample. In order to do that, a certain chemical ingredients are needed to mix

together with and left it in a sample mould for it to be harden. Here are the steps for

sample mounting.

1. Mount specimen on the lid of the reusable mounting cup.

2. Apply release agent to the reusable mounting cup side wall.

3. Mix 5:1 resin to hardener by weight. Stir until the mixture is warm. Additional 1g

of hardener to the mixture is recommended to boost the curing process.

4. Put the mixture in the vacuum impregnation system to de-bubble for 1 minute.

5. Pour the mixture into the mounting cup carefully.

6. Put the mixture in the vacuum impregnation system to de-bubble for 3-4 minutes,

switch of the system and keep for 5 minutes.

7. Release the chamber valve, and keep until the resin is fully cured.

Report done by,Lee Kok Yew Page 32

EpoxyResin (left), hardener (right)

5:1 (by weight) Add 1g hardener to boost the

curing time

Stirring stickMixing cup Gloves

+

Release agent Reusable mounting cupApply release agent to

the reusable mounting cup side wall.

Specimen mounting clip

←→

Double sided tape

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GRINDING

After the sample is harden enough, the sample is being take out from the mould. Now is

the grinding process. Grinding is use of grinder machine to cut or grind the sample into a

certain level to observe the structure of the unit. It uses sand paper (SiC paper) to grind

the unit. There are a certain label of sandpaper needed to follow. It start with 240 grit,

400 grit, 600 grit, 800 grit and lastly 120 grit. Theses sandpaper is being differentiate by

the surface smoothness. All begin with rough sandpaper then continuous with a smoother

surface until the smoothest and finest sandpaper is being use at last.

Grinding process is stop until

the require level of

observation of the sample is

being found. After that, the

sample is needed to polish to

have a clearer and better

vision.

Report done by,Lee Kok Yew Page 33

400 grit SiC paper

240 grit or lower SiC paper

600 grit SiC paper

800 grit SiC paper

1200 grit SiC paper

SiC abrasive paper

Grinding

Frequent Inspection

Recommendation for package cross-sectioning

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POLISHING

The purpose of polishing is to softly grind the ground surface and create a smooth,

shinning, less undulation or flat surface by using better shock absorption grinding media.

There are two types of polish which are

1. Rough polish– remove scratches

- Hard cloth – Allied Kempad polishing cloth.

- Apply diamond suspension 6um & 3um

- Less “pull-out”, abrasive

2. Fine polish – to clean up blemishes

- Superior scratch removal

- Apply diamond suspension 1um

- Easily generate surface “relief” – smear

- Pull-out effect

- Final Polish

The procedures for polishing process are below

1. Place the polishing plate on the wheel base.

2. Let runny water on the rotating plate for about 2 minutes to clean the polishing pad.

3. Dry the pad by rotating the plate.

4. Apply necessary lubricant.

5. Polish with lower force.

6. Clean the sample with water and frequent inspect.

7. Final polish the sample for 10-15 seconds.

8. Clean and dry specimen.

9. Wash the polishing pad and dry it.

INSPECTION

For small feature, visual inspection at high magnification (mag x500) is required.

Frequent inspection during the grinding and polishing process is essential to avoid any

overgrinding.

Report done by,Lee Kok Yew Page 34

Diamond suspension

0.05um Alumina suspension

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5.3 FINAL TEST

5.3.1 LOW POWER MICROSCOPE

The low power microscope is quite often used to capture pictures of power

packages as it increases the size of the picture so that a clear view of the packages can be

taken. There are various sizes where it can focus and measurements can also be taken on

these power packages using the low power microscope. A computer is connected to this

microscope and the picture can be seen on screen. Tiny power packages are normally

enlarged so as to view better images of the packages and usually, it is used to capture

pictures of the external surface of the packages and also after decapsulation. It can also be

used to see if there are any cracks of the power packages as these cracks cannot be seen

by naked eyes.

Low power microscope have been use for visual inspection should be carry out to

ensure there is no defect on the physical of the product, for example: external void/

bubbles, solder overflow incomplete mold, pitted surface, dirty unit chip/crack casing,

lead frame damage, compound overflow, clamp mark, scratches, flashes, and package

crack.

Figure 29: Low Power Microscope

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Package crack- Contamination on leadframe or cutting insert causes dent

on the leadframe.

Warpage Substrate- The loss of planarity of a plastic encapsulated molded

surface, excluding protrusions and intrusions.

Resin Bleed - Thin Transparent (sometime light yellowish) layer of mold

compound, remaining on leads, which is removable by Deflashing

Process.

Flashes- Flashes are the excess plastic material sticking out of the package

edges right after molding.

Flash/ Bleed- Bleed (transparent or light coloured) on leads and die pad at

package.

External Void/bubbles- Bubbles look alike structure on mold surface.

Pitted Surface- Reject for pitted surface > 1mm in length.

Crack Casing- Break-away mold compound or crack lines on units.

Scratches on Package- Reject for scratches on the top or bottom packages.

Leadframe Damaged- Physical damaged to leadframe that make it difficult

to process in the downstream machine and has reliability issue.

Compound Overflow- Mold compound covers too much of leadframe or

substrate and it is difficult to process through the downstream machine.

Report done by,Lee Kok Yew Page 36

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5.3.2 HIGH POWER MICROSCOPE

The functions of a high power microscope are similar to the functions of low

power microscope. The difference is just that the high power microscope can enlarge the

images of power packages much more compare to the low power microscope. The high

power microscope are usually used to capture images of power packages after cross

section as it can focused more to the internal of the packages. A computer is also

connected to this high power microscope and measurements can also be taken using the

software provided.

High Power Microscope have been use for visual inspection should be carry out

to ensure there is no defect on the physical of the product, for example: oxidation mark,

cut mark, abnormality 3, wire mark imprint, solder balling, solder on die, and solder

overflow

Figure 30 : High power microscope

Figure 31: Oxidation mark Figure 32: Cut Mark

Report done by,Lee Kok Yew Page 37

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6.0 PROJECT IN ON SEMICONDUCTOR

During my 12 weeks of internship period, I was assigned a task together with

another trainee. The task is to come out a mechanism that is able to transfer the unit from

one medium to another medium. More precisely, it means the mechanism is enabling the

operator to transfer the unit from plastic tube to metal tube and vice versa. We were given

a budget of total RM8000 for the design. My partner studied in product engineering so

the main idea of the mechanism is mainly design by her as she knows how to use AUTO

CAD to design it through computer. I was in charge of the electrical and mechanical part.

That is the valve of the mechanism, the air-cylinder and the circuit that control the whole

mechanism.

This is

the

roughly

idea of

the

mechanism that needed to be build out. The mechanism is able to transfer 4 tube of fully

loaded unit at a same time. The unit can be flow from metal tube to plastic tube and from

plastic tube to metal tube. It is fully control by the mechanical circuit.

PURPOSE

Report done by,Lee Kok Yew Page 38

PLASTIC TUBE

METAL TUBE

COVER

SUPPORT

DOUBLE ACTING AIR-CYLINDER

BASE

PLASTIC TUBE LOADER

METAL TUBE LOADER

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The purpose of this mechanism is to simplify the operator when transferring the unit from

one medium to another. Before that, the unit is being transfer manually by the line

operator. It is so troublesome and sometimes the unit being drops out and left it scatter

around the floor. It will lead to production losses that will affect to the company.

PROCEDURE

I will briefly describe the

step and procedure for what

I have done during the

creation and assembly for

the mechanism.

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Unit is being transfer manually by the operator from one side to another.

The metal tube that will be put inside the oven for high temperature testing.

After being transfer, the unit will be put in the plastic tube and ready to do final packaging.

At the end of the day, you can see the unit being drop out during the transferring process.

The unit being scatter around the floor

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Report done by,Lee Kok Yew Page 40

Thickness = 0.0364Tolerance = 0.01Unit in Inches

Thickness = 0.0345Tolerance = 0.01Unit in Inches

Plastic Tube and the dimension that is going to connect in the mechanism

Metal Tube and the dimension that is going to connect in the mechanism

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Report done by,Lee Kok Yew Page 41

When the two inlet of both tube is connected, there is a small different of error. The plastic tube dimension is slightly bigger then the metal tube. Thus, it causes the unit unable to flow in from 1 of the tube to the other side of the tube.

Offset for both plastic and metal tube when connected

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MECHANICAL AND

ELETRICAL PART

In the mechanism, I was

in charge of select and

design the suitable

mechanical equipment

that is usable for the

mechanism. The whole

mechanism platform is

function by the Double

Acting Air-Cylinder.

The knocker function is

to generate a non-stop

vibrating to the platform

so that the unit will keep

on flow from tube to

tube.

DOUBLE ACTING

ARIR-

CYLINDER

• For this

mechanism, we

Report done by,Lee Kok Yew Page 42

PLASTIC TUBE

METAL TUBE

COVER

SUPPORT

DOUBLE ACTING AIR-CYLINDER

BASE

PLASTIC TUBE LOADER

METAL TUBE LOADER

Overall idea and the part of the mechanism

Mechanical and electrical part for the mechanism

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are using double acting Air-Cylinder to move the platform upward and

downward.

• Based on the calculation and aspect needed, the type of cylinder that we are using

is Compact Cylinder ISO Standards [ISO/21287] C55B-60

• From the requirement, we found that the bore size that is needed is 20 mm and

stroke size is 60mm.

KNOCKER

• Purpose is to knock the tube (plastic and

metal) so that the unit will not stop in between

when the platform is being tilt.

• The knocker will vibrate the tube and cause

the unit to flow smoothly.

• There are 8 knockers on the platform.

• 4 in the metal tube side and the other 4 in the plastic tube side.

Report done by,Lee Kok Yew Page 43

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CIRCUIT DIAGRAM

KNOCKER

• This is the knocker circuit diagram.

• The control valve will cycle the air pressure to the

knocker to create the pulsation to the knocker.

• Thus it create a non-stop knocking process until the

air pressure is cut off

VALVE AND THE AIR-CYLINDER (moving upward)

• The piston is moving upward.

• Air pressure is going in through point A and coming

out through point B

• Using 5/2 valve to control the air flow.

VALVE AND THE AIR-CYLINDER (moving downward)

• The piston is moving downward.

• Air pressure is going in through point B and

coming out through point A

• Using 5/2 valve to control the air flow.

Report done by,Lee Kok Yew Page 44

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7.0 PROBLEM

Below are some problems that I face during my practical industrial training

program. These listed below:

The chance for me to communicate to senior engineers as formally is limited.

I cannot optimize my ability to enhance my knowledge during an idle time.

Some material is confidential; therefore I didn’t allow enclosing together with my

report.

There is limited table and computer for trainee to use during the internship.

Therefore, we need to share table and pc with more than 2 people.

In the lab, some of the equipments are too expensive; therefore we need our

supervisor to accompany us when using it. It is quite troublesome.

Some of the places in the production line are forbidden for trainee to go and

therefore is limited for us to learn something.

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8.0 REFERENCES

http://sbnportal.onsemi.com

http://www.onsemi.com

http://newtsbn-a2.onsemi.com

http://www.onsemi.com/PowerSolutions/products.do

Operation manual

Explanation from engineer

Observation and experience

Report done by,Lee Kok Yew Page 46