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IC Package, Assembly Technology
CONFIDENTIAL 2
An integrated circuit is a small but sophisticated device implementing several electronic functions.It is made up of two major parts: a tiny and very fragile silicon chip (die) and a package which is intended to protect the internal silicon chip and to provide users with a practical way of handling the component.
This presentation describes the various “front-end” and “back-end” manufacturing processes. This technology is used for the majority of the ICs manufactured.
I C – Integrated Circuit
CONFIDENTIAL 3
THE FABRICATION OF A SEMICONDUCTOR DEVICE
The manufacturing phase of an integrated circuit can be divided into two steps. The first, wafer fabrication, is the extremely sophisticated and intricate process of manufacturing the silicon chip.
The second, assembly, is the highly precise and automated process of packaging the die. Those two phases are commonly known as “Front-End” and “Back-End” that includes two test steps: wafer probing and final test
CONFIDENTIAL 4
Front End Process
CONFIDENTIAL 5
WAFER FABRICATION ( FRONT-END )
Identical integrated circuits, called die, are made on each wafer in a multi-step process. Each step adds a new layer to the wafer or modifies the existing one. These layers form the elements of the individual electronic circuits.
The main steps for the fabrication of a die are summarized in the following table. Some of them are repeated several times at different stages of the process. (The order given here doesn't reflect the real order of fabrication process.)
CONFIDENTIAL 6
CONFIDENTIAL 7
Photo Masking Process
CONFIDENTIAL 8
Etching Process
Diffusion Process
CONFIDENTIAL 9
Metal Deposition Process
CONFIDENTIAL 10
Backend Process
CONFIDENTIAL 11
IC Packaging
CONFIDENTIAL 12
leadframe
plastic compoundwire
die pad
die attach
IC Package Compositionsilicon chip
CONFIDENTIAL 13
•Through-hole mount packages •Surface mount packages
CONFIDENTIAL 14
CompanySet-up
(Y1966)
His
tory Start IC
Assembly(Y1969)
Start IC Testing(Y1974)
Set up IC PKGDev’t Center(Y1987)
Start IC Wafer testing(Y1989)
QFP packageIntroduction (Y1992)
1966 1980 1995 2000 2005 (Year)
Matrix
LFBGA
HSOP-24
SO-14/16/24/32..5
6
QFP-32/48/..80
Resistor
capacitor
VSO-40/56
SIL-9
SIL-13/17/23
DBS37P
DIP-16/18/24…40
SDIP-24/32…64
SSOP-16/20
VSO-101
HDIP-18
LQFP48
QFP-100…208
TrimmerIntroduction(Y1968)
Film ResistorIntroduction(Y1969)
Packag
e D
istr
ibu
tion
QFP stacked die(QFP MCM)
Chip Sorting
BGA PKGIntroduction
(Y2000)
COF/Leadfree Introduction
(Y2002)/(Y2005)
TFBGA
HBGA
COF
Flip Chip
Package Roadmap (APK)
Dark Green compound Intro
(Y2006)
POP
2007
PoP sbSiP
(Y2007)
sbSiP
CONFIDENTIAL 15
LQFP208 Single Chip
CONFIDENTIAL 16
In past 7 years, APK delivered > 550Mpcs of MCP products
MCP (multi-chip package) products
CONFIDENTIAL 17
Stacked die product
In past 3 years, APK delivered > 100Mpcs of stack-die products
CONFIDENTIAL 18
APK MCP products
CONFIDENTIAL 19
OM48102OM6115
OM48102
OM48316
QFP100_3-stacked dies
LQFP100_4-stacked dies
OM48316
OM48102OM48102
Dummy
OM6115
Multi Chip Stacked Die
CONFIDENTIAL 20
CONFIDENTIAL 21
Stack die assembly of QFP100
CONFIDENTIAL 22
APK stacked die productQFP100 (PCD80716H) QFP100 (PCD8017H) SDIP56 (SAA4849PS)
LFBGA228 (PCF5213-1) LFBGA81 (PCD87750) HTQFN48 (BGB204)
CONFIDENTIAL 23
PCD8017H
OM48316
OM48102
OM6115 OM48102
OM48102OM6115
OM48102
OM48316
QFP100_3-stacked dies RFS in Nov.’03
LQFP100_4-stacked dies to be evaluated
OM48316
OM48102
OM48102
Dummy
OM6115
Conception – for 4-stacked dies pre-development
Package thickness=2.8mmDie thickness=200um
Package thickness=1.4mmDie thickness=100um
Glue
B-stage/DAF
add a dummy spacer
Assy, F/T, Reliability test
CONFIDENTIAL 24
Bottom die - top die
L/F to top die(overhang)
Die-die-die bonding
BSOB under top die
APK 4-stacked die concept development
BSOB under top die
Overview
CONFIDENTIAL 25
- The BGT215 is designed for TV-enabled cellular handsets (TVoM). This complete, low-power front-end solution is the fast way to add TV functionality to a cellular phone.
- Related technologies :
- Flip chip on substrate
- Flip chip on die
- Stack dies
- Package : HLQFN 7x7x1.2 mm
- One lot reliability result available:
- MSLA passed Level 2
- THB 1000 hr passed
- 110 C UHST 264 hr passed
- TMCL 500 cycle passed
- About 16 K samples produced, assembly yield is about 98 %
BGT215 MCM with flipchip
Substrate
BBPICS
TUNER
CONFIDENTIAL 26
BGT215 Construction
Interconnect Tuner/PICS
Interconnect BB/substrate
Interconnect wire/Pics
Interconnect wire/substrate
CONFIDENTIAL 27
PNX0151 / LFBGA169
CONFIDENTIAL 28
PNX0151 / LFBGA169
CONFIDENTIAL 29
PNX0151 / LFBGA169
CONFIDENTIAL 30
(tbd)
CONFIDENTIAL 31
IC Package Assembly Process
CONFIDENTIAL 32
Glossary L/F – leadframe
Substrate; laminate; PI(poly-imide) tape; film
D/A - die bond, die attach
die attach, glue, epoxy glue, alloy, soft solder, DAF, die attach film
W/B - wire bind, ball-stitch bond
Au wire, AuPd wire, Cu wire, Al wire
T/M - transfer molding, molding, encapsulation
EMC(epoxy molding compound), compound, plastic
Deflash
M/K; L/M - marking, laser marking
T/P - tin plating, solder plating, plating, strip plating
D/J - dejunk; dambar cutting
T/F - trim/form, lead cut/bend
B/M - ball mount
S/G - sawing, singulation
CONFIDENTIAL 33
Leadframe
CONFIDENTIAL 34
Different Carriers : leadframe, laminate, film…
CONFIDENTIAL 35
Grind/Sawing Die Bond Wire Bond Molding
Trim/Form Plating
Wafer-test
Shipment
Wafer
Testing Marking
TAIWANP32P4910ABE2
C636604 9647SB
TAIWANP32P4910ABE2
C636604 9647SB
Typical Assembly Flow ChartTypical Assembly Flow Chart
CC+Cure
Cure
Dambar cut, D/J
PMCPacking
CONFIDENTIAL 36
Die bonding
CONFIDENTIAL 37
Glue dispenser -needle dispenser (dot)-pen writer (pattern)
•Glue volume/dispenser control•Die placement/bond force control
•Bond line thickness (BLT)•Fillet height•Glue wetting•Die position
Epoxy glue-normal oven cure (1-2hrs)-snap/fast cure (couple minutes)
curing
Die bonding
CONFIDENTIAL 38
Wire bonding
CONFIDENTIAL 39
Wire bonding
CONFIDENTIAL 40
Wire bonding
CONFIDENTIAL 41
1st bond (ball)
2nd bond (stitch)
•Metal peeling off (MPO)•Chip out under bond (COUB)•Incorrect ball size•Loose/lift ball bond•Losing tail•Ball short/shift•Ball deformation (e.g. golf)•Ball neck crack/broken
•Loose stitch bond•Misplaced stitch•Stitch broken
•Wrong wire loop•Wire damage/scratch•Wire short•Wire broken
Wire bonding – typical failure mode
CONFIDENTIAL 42
1st bond (ball) 2nd bond (BSOB)
Die 1 Die 2
Die-to-die wire bonding for MCM
Wire bonding – MCM
CONFIDENTIAL 43
top mold
bottom mold
transfer plunger
mold pellet air vent
primary runner
secondary runner
gate
void
Molding
CONFIDENTIAL 44
• Void (internal/external)
• Incomplete Fill
• Wire Sweep
• Wire Deformation/Broken/Short between
• Resin Bleed/Flash
• Mould Sticking
• Gate Remains • Body Chip Out
• Body Shift
• Die Crack
• Die Paddle Shift
de-gate
Molding – typical failure mode
CONFIDENTIAL 45
QFN package
CONFIDENTIAL 46
What is QFN?
QFN is a package in lead-frame based technology
With lower parasitic impedance and thermal resistance, small size and light, the package is suitable for middle to low pin count with high frequency applications
The cost is also low. For all the reasons, the package is now drawing high attention in the market
The external-exposed die-paddle and shorter wire path and leads have improved the power dissipation and reduced the parasitic impedance
The size of the package is around ½ of the size of QFP in the same pin count when replacing it with QFN.
CONFIDENTIAL 47
Source: Prismark
CONFIDENTIAL 48
Body size (mm) Lead count Thick (mm)
2.5x2.5 (or below) 4/8/10/12/14 0.85
3x3 4/8/10/12/16 0.85
4x4 12/16/20/24 0.85
5x5 16/20/28/32/36 0.85
6x6 20/28/32/36/40/48/52 0.85
7x7 28/32/44/48 0.85
8x8 32/40/52/56/68 0.85
9x9 36/44/60/64 0.85
10x10 44/52/68/72 0.85
12x12 88/100 0.85
Miniaturized body
High I/O
HVQFN standard configuration options
CONFIDENTIAL 49
HVQFN inside view
HVQFN bottom view
CONFIDENTIAL 50
Cross-section of HVQFN soldering Schematic of daisy-chain
PCB footprint design of HVQFN
CONFIDENTIAL 51
HVQFN cross-section
*Tape at the bottom of leadframe
CONFIDENTIAL 52
half-etching
HVQFN 5x5
* QFN L/F taping
CONFIDENTIAL 53
HVQFN 10x10
CONFIDENTIAL 54
Typical HVQFN assembly processDie attach
Glue curing
Wire bond
Plasma
Molding
Tape detach
Post mold cure
Deflash (chemical)
Laser marking
Sawing
Manual, to remove the tape on the backside of leadframe
Clean the leadframe to provide a better mold adhesion
Epoxy glue (soft-solder optioned for high thermal)
Au/AuPd wire
Plastic encapsulation for leadframe strip with backside taping
Remove plastic residue on exposed pads/lands
Laser mark product ID codes on package body
Sawing mold map into package unit
Oven cure for hardening molding compound completely
Oven/snap cure to solidify epoxy glue
CONFIDENTIAL 55
BGA package
CONFIDENTIAL 56
BGA – category in JEDEC
CONFIDENTIAL 57
BGA – substrate
CONFIDENTIAL 58
BGA
top side
bottom side
CONFIDENTIAL 59
BGA – substrate
CONFIDENTIAL 60
CONFIDENTIAL 61
BGA – assembly flow
CONFIDENTIAL 62
BGA molding
CONFIDENTIAL 63
BGA fluxing (ball mount)
CONFIDENTIAL 64
BGA (fluxing ) ball mount
(fluxing)
CONFIDENTIAL 65
BGA ball mount defects
CONFIDENTIAL 66
IC Package MSL
CONFIDENTIAL 67
prec
ondi
tioni
ng
SHIPMENT
Reflow for SolderingReflow for Soldering245~260 °245~260 °CC
PCBPCB
Application
CONFIDENTIAL 68
What is MSL (Moisture Sensitivity Level)What happens to the product ?
1
3
2
4
MSL=1 : NOT moisture sensitive product
MSL>1 : Moisture sensitive product
CONFIDENTIAL 69
solder
solder
MSL levels applicable to :SMD packages
–in REFLOW soldering process
–in WAVE soldering process
MSL levels NOT applicable to :Through Hole packages (WAVE soldering)
CONFIDENTIAL 70
Source: Infineon
POPCORN
CONFIDENTIAL 71
MSLAssessment is used to:- Rate Moisture Sensitivity of package part
- MSL 1, 2, 3 etc.
- Determine safe packing method for delivery
- Dry Pack – Yes (L>1) or No (L=1)
- Determine safe handling procedures
- Let the customer know how to handle parts
- Prevent reflow related package failures (popcorn)
- No Customer Complaints
CONFIDENTIAL 72
Peak Body (Classification) temperatures defined by:
-Package Thickness (incl LF/ substrate)
-Package Volume
CONFIDENTIAL 73
MSLA Procedure
►SCAT Test - As received parts
►Moisturize parts - Condition for MSL level
►3x Reflow parts - Per JEDEC Profile
►( Electrical Test )
►SCAT Test
►Cross-section
►Rate MSL Level and Report
CONFIDENTIAL 74
Industry Specs:
–IPC/JEDEC J-STD-020C MSLA (July 2004)
–IPC/JEDEC J-STD-033 (Handling/Packing)
–Jeita ED4701
MSL levels vs floor life
CONFIDENTIAL 75
MSL levels and Peak Body temperatures are printed on packing labels to alert customers on how to handle.
CONFIDENTIAL 76
Handling Moisture Sensitive Packages
Keep parts in dry bags until use
Use Floor Life based on MSL level
Once dry bag is opened Floor Life Clock can’t be stopped
- Special 1 hour rule - can open and reseal bag within 1 hour
Short Duration Exposure rule - If parts exposed to factory ambient for less than 8 hours Floor Life clock can be reset by 5X exposure time in dry box (< 10% RH)
If parts exceed Floor Life they must be baked before reflow
For Failure removal from Board part must be dry and low temperature should be used
CONFIDENTIAL 77
External Cracks
CONFIDENTIAL 78
Internal Cracks Intersecting Bond Wire
Ball bond
CONFIDENTIAL 79
Internal Crack Extending to Lead Finger
CONFIDENTIAL 80
Internal Crack more than 2/3
CONFIDENTIAL 81
Swelling (popcorn)
CONFIDENTIAL 82
Die Lift
CONFIDENTIAL 83
Stitch/Downbond CrackingPLCC44 Stitch Cracks
SCAT inspection after MSL level 1.
SCAT inspection after MSL level 2. SCAT inspection after MSL level 3.
SEM photo of stitch bond crack after MSL SEM photo of stitch bond crack after level 1 test. MSL level 2 test.
CONFIDENTIAL 84
Die Delamination
CONFIDENTIAL 85
Delamination on Wire Bond Surface
CONFIDENTIAL 86
IC Package Reliability
CONFIDENTIAL 87
Reliability The probability that a IC package will perform a requiredfunction without failure– under specified conditions– for a stated period of time
First Level– Stand alone IC package, not soldered on a PCB– Second level: Board Level Reliability
First Level Reliability
CONFIDENTIAL 88
Probability: “Bath-tub Curve”
Failu
re r
ate
(
)
Time
Intrinsic FailureRegion
MTBF applied in this range
Wear OutRegion
0 168 hrs
1000 hrs
EarlyFailureRegion
CONFIDENTIAL 90
prec
ondi
tioni
ng
SHIPMENT
Reflow for SolderingReflow for Soldering245~260 °245~260 °CC
PCBPCB
Application
CONFIDENTIAL 91
Reliability Stress Test
PCBPCB
Precon TestPrecon Test((shipment and mountingshipment and mounting))
Environmental TestEnvironmental Test((field applicationfield application))
Test to asses the endurance of encapsulated semiconductor devices by “accelerating” the conditions in shipment, SMT & application
CONFIDENTIAL 92
preconditioning
Electr. M. / Inspection*
*Inspectione.g. SCAT
Reliability Stress Test Flow
temperaturecycling
unbiasedhumidity
biasedhumidity
hightemp. storage
Finished Products
Electrical Measurement / Inspection*
Electrical Measurement / Inspection*
CONFIDENTIAL 93
• HAST (UHST with bias): 130 °C / 85% RH Horizontal chamber
• Alternatives: - 85 °C / 85% RH (THB) - 110 °C / 85% RH
Biased humidity: HAST
CONFIDENTIAL 94
PurposeTo assess the sensitivity of non-hermetic packaged solid-state devices, after shipment (environmental stresses), to PCB mounting (hot convection reflow soldering)Conditions are according to the assessed Moisture Sensitivity Level (MSL)
PRECON Test
PCBPCB
CONFIDENTIAL 95
PurposeTo asses the endurance of non-hermetic packaged solid-state devices exposed to mechanical stress as a result of expansion and contraction by high and low temperature
Conditions -55/+125 °C or -65/+150 °C
TMCL Test
- 55 °CAir
125 °CAir
Expansion
Contraction
CONFIDENTIAL 96
PurposeTo assess the resistance of non-hermetic packaged solid-state devices to the effect of moisture intrusion
Conditions
PPOT: 121 °C, 100% RH (103.4 Kpa)
UHST: 130 °C, 85% RH (263 Kpa)
PPOT/UHST Test
PPOTCHAMBER
Accelerated intrusion of moisture
Towards electrochemically sensitive areas(e.g. die surface: bond pad corrosion)
Through the surrounding moulding compound
or directly via gaps, cracks and delaminated areas(as a result of Precon)
MoistureMoisture
CONFIDENTIAL 97
PurposeTo evaluate the reliability of non-hermetic packaged solid-state devices in humid environments where temperature, humidity, and bias accelerate the penetration of moisture
Conditions
THB: 85 °C, 85% RH with bias
HAST: 130 °C, 85% RH with bias
THB/HAST Test
THB/HAST
CHAMBERV
Accelerated intrusion of moisture & drift of impurities; extra driving force: E-field
Towards electrochemically sensitive areas; extra driving force: V(e.g. die surface: bond pad corrosion)
Tthrough the surrounding moulding compound
or directly via gaps, cracks and delaminated areas(as a result of Precon)
Moisture
V
-
--
++
+Emax = V / dmin
MoistureMoisture
VV
-
--
--
----
++
+
++++
++Emax = V / dmin
CONFIDENTIAL 98
PurposeTo asses the endurance of IC products when exposed to a high temperature for a long time period
Condition
150 °C
HTSL Test
HTSL150 °C
CONFIDENTIAL 99
Environmental Stress Test Abbr. Stress Conditions
Requirement
Highly Accelerated Stress Test HAST 130°C, 85% RH,biased
96 hr
Temperature Humidity Bias, Static/ Cycled Test
THBS/THBC
85°C, 85% RH,biased
1000 hr
Preconditioning PRECON per MSL,1/2(a)/3/4/5(a)/6
passlevel
Unsaturated Pressure Cooker UHST 130°C, 85% RH,unbiased
96 hr
Pressure Cooker test PPOT 121°C, 100 % RH, unbiased
96 hr
Temperature Cycling Test, (Condition C)
TMCL “C” -65°C to +150°C,unbiased
200 cls
Temperature Cycling Test, (Condition B)
TMCL “B” -55°C to +125°C,unbiased
500 cls
High Temperature Storage Test HTSL 150°C 1000 hr
Environmental Tests & Conditions
CONFIDENTIAL 100
PRECON: solder migration
CONFIDENTIAL 101
PRECON: external package crack
CONFIDENTIAL 102
PRECON: internal package crack
External crack
Delamination propagates into a package crack and severs the ball bond.
CONFIDENTIAL 103
PRECON: popcorn
SCAT / B-ScanSCAT / C-Scan
CONFIDENTIAL 104
PRECON/TMCL: die lift
die crack & delamination
diedie
underfillunderfilldelaminationdelamination
crackcrack
die lift
CONFIDENTIAL 105
PRECON/TMCL: Stitch Bond Break
CONFIDENTIAL 106
PRECON/TMCL: ballneck break
CONFIDENTIAL 107
PRECON/TMCL: bond ball lift
chip out under bond
CONFIDENTIAL 108
PRECON/TMCL: solder ball crack
Bump Crack (solder fatigue) as a result of delamination
DieDie
UnderfillUnderfill
Bump CrackBump Crack
BumpBump
Flip Chip - PASSI on laminate: CTE- mismatch between substrate and die- solved by selection and applying underfill
CONFIDENTIAL 109
TMCL: passivation crack / pattern shift
CONFIDENTIAL 110
TMCL: package Crack
CONFIDENTIAL 111
PPOT/UHST/THB/HAST:wet bondpad corrosion
Micro gap
Ionmigration
Moisturepenetration
CONFIDENTIAL 112
PPOT/UHST/THB/HAST:dendritic growth & leakage path formation
Pin 6 Pin 7
Ag dendrite formation / current leakage
Cu dendrite formation / current leakage
CONFIDENTIAL 113
THB/HAST: charge creep
HV (x100 V)
- +
• no catastrophic failure;
• but a leakage resulting in circuit malfunction (reversible, can be baked out)
Circuit malfunction in high voltage devices (typically a few hundred volts) due to charge accumulation at the silicon-to-plastic interface
CONFIDENTIAL 114
HTSL: dry corrosion
ball delamination
Cu
Cu9Al4
CuAl
CuAl2
Al
Delamination starting at ball edges
CONFIDENTIAL 115
HTSL: Kirkendall voiding
THANK YOU !
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