QFN Bonding Capillaries from SPT (SQ Series)

QFN Bonding Capillaries from SPT (SQ Series)

As the consumer market aggressively demands for the miniaturization of electronic products with more functionality, the requirement for small IC components has significantly increased, particularly on QFN packaging. Two major advantages of QFN over other leaded packages are - cost to manufacturer (for small, thinner, lighter in size, hence promoting more units per lead frame) and improved performance ICs (for better thermal dissipation and reduction in lead inductance).

In general, QFN packages are available in two types - a punch type and a sawn type. A sawn type typically comes with a polyimide tape before die attach or wire bond process. The purpose of the tape is to prevent the bleeding of the resin from the moulding compound into the backside of the QFN leadframe. However, the polyimide tape causes the lead to bounce when exposed to high temperature coming from the heater block.

TAPELESS QFN Punch Type Bonding Capillaries from SPT (SQ Series) Punch Type Polyimide Underneath Strip QFN Bonding Capillaries from SPT (SQ Series)

Challenges of Bonding QFN
QFN wire bonding has its own special characteristics as compared with other leaded packages. Looking at the wire bond process set up, QFN is much more complicated than other packages and these are highly influenced by the clamping, lead bouncing and lead design.

The QFN package tie bar width and thickness design greatly affect the wire bonding performance. Wider and thicker lead configuration are preferred as this will have lower reaction towards leads bouncing during the wire bonding process. Lead bouncing is more prominent on tape QFN where the tape actually “softens” when subjected to high bonding temperature of equal or more than 200˚C. The “softening” effect will absorb certain amount of USG power needed for a better weld of the wire to the lead surface to form the stitch.

 effect of  QFN matrix leadframe made it impossible to design a clamping system which will hold the middle fingers (SQ Series)

The effect of QFN matrix leadframe made it impossible to design a clamping system which will hold the middle fingers at the centre of the bonding area

(Figure 2). Under this condition, the best way to clamp or hold QFN matrix leadframe would be around its perimeter. Consequently, this leaves the middle of the QFN matrix leadframe area prone to micro bouncing. The micro-bouncing effect will always be inherent with the QFN bonding (with tape underneath), causing some instability issue in second bond deformation.

In a typical stitch bonding (second bond) process, the use of lesser USG power setting is more preferred for QFN with tape underneath. This is to minimize the micro bouncing effect translated to the ball bond (first bond) causing ball neck stress or damage.

The introduction of thermocompression (a combination of force & temperature - Figure 4) - alleviates micro-bouncing effect on the QFN matrix leadframe, resolving ball neck stress or damage. Usually, a longer bonding time of more than 15 milliseconds with high and gradually ramping up bond force profile, ranging from more than 100g to less than 500g (depending on wire size) are pre-requisites for good thermocompression bonding. The introduction of thermocompression bonding reduces the effect of the micro bouncing providing better quality bonding and smoother bonding performance that are necessary in mass volume production environment.

 effect of  QFN matrix leadframe made it impossible to design a clamping system which will hold the middle fingers (SQ Series)
Figure 4: Use of thermocompression in QFN

What is SPT’s new SQ capillary?
SPT’s new SQ capillary series features a consistent surface morphology finishing used for both gold (Au) and copper (Cu) wires, specifically developed for QFN wire bonding. The SQ capillary is designed in line with thermocompression bonding concept. The uniqueness of the SQ capillary is shown in the actual bonding response in terms of higher productivity (due to improved MTBA & higher capillary touchdown) and reliability of the bonded product.

Improved MTBA
QFN Improved MTBA (SQ Series)
With SQ capillary, there will be lesser assist due to short tail or broken stitch which is inherent with bonding QFN package. Experience more machine uptime!

Higher Capillary Touchdown
QFN Higher Capillary Touchdown Table(SQ Series)
SQ capillary coupled with optimized bonding parameters, has proven to deliver an increase in the capillary tool life as lower bond force (BF) is utilized to bond the QFN package.

Proven Reliability
Whether on gold or copper wire, the SQ capillary is designed to enhance the formation of larger & width stitch bond that will effectively increase the stitch pull reading values & longer size copper remains.

Popular Designs For Copper

Bond
Pad Pitch
µm
Useable
Wire Diameter
µm
H
µm
CD
µm
FA
°
T
µm
Recommended SPT Part Number
50 20 25 30 11 63 SQ-25063-305F-ZU39TS
60 23 28 35 11 80 SQ-28080-355F-ZU39TS
60 25 30 38 11 80 SQ-30080-385F-ZU39TS
70 25 33 43 8 90 SQ-33090-435E-ZU39TS
80 25 33 48 8 100  SQ-33100-485E-ZU39TS
80 30 38 51 8 100  SQ-38100-515E-ZU39TS
90 25 35 51 8 110  SQ-35110-515E-ZU39TS
90 30 38 53 8 110  SQ-38110-535E-ZU39TS
100 30 38 55 8 130  SQ-38130-555E-ZU39TS
110 33 41 58 8 165  SQ-41165-585E-ZU39TS


Popular Designs For Gold

Bond
Pad Pitch
µm
Useable
Wire Diameter
µm
 H
µm
CD
µm
FA
°
 T
µm
Recommended SPT Part Number
50 20 25 30 11 63 SQ-25063-305F-ZS39TS
60 23 28 35 11 80 SQ-28080-355F-ZS39TS
60 25 30 38 11 80  SQ-30080-385F-ZS39TS
70 25 33 43 8 90 SQ-33090-435E-ZS39TS
80 25 33 48 8 100  SQ-33100-485E-ZS39TS
80 30 38 51 8 100  SQ-38100-515E-ZS39TS
90 25 35 51 8 110  SQ-35110-515E-ZS39TS
90 30 38 53 8 110  SQ-38110-535E-ZS39TS
100 30 38 55 8 130  SQ-38130-555E-ZS39TS
110 33 41 58 8 165  SQ-41165-585E-ZS39TS


Capillary Part Number Selection Guide

The capillary design selection guide is always based on specific device & package configuration, wire type, and wire bonder. The selection of capillary part number process is simplified as follows:

Capillary Tip The selection of capillary tip design is determined by the device and metallization, bond pad pitch, bond pad opening, wire size, target mashed ball diameter, and critical loop height to derive the hole diameter(HD), chamfer diameter (CD), chamfer angle (CA), tip diameter (T) and face angle (FA).

Shank Style The shank style selection is characterized by geometrical design of the capillary bonding tool as dictated by specific device and / or package configuration.

Surface Finish The selection of a particular capillary tip surface finish hinges on whether the application is for gold or copper wire bonding.

Material Capillary material selection for optimum tool life performance for a given bonding application.

Wire Type The proper selection of capillary design is a resultant of the various wire bonding considerations.

Fine Pitch Part Number Selection

Infinity 3X Longer Tool Life

SPT 'Infinity' capillary material extends the tool life up to 3X its original tool life. This option is available on many tools and is a proprietary process SPT use to increase tool life.


ORDERING INFORMATION (PLEASE ADVISE REQUIREMENTS & QUANTIY FOR QUOTE OR ASSITANCE)
Part Number - SQ Series QFN Wire Bonding CapillariesPRICE QUOTE - email us at sales@epakelectronics.comSQ Series QFN Wire Bonding Capillaries Brochure


BONDING CAPILLARIES & ACCESSORIES WE OFFER:

Non-Fine Pitch Capillaries (UT)UT NON-FINE PITCH CAPILLARIES
QFN (Quad Flat Non-Lead) SQ Capillary for gold and copper wire bondingQFN PACKAGE COPPER & GOLD WIRE BONDING CAPILLARY
Copper Wire Bonding Capillaries (SU)COPPER WIRE BONDING CAPILLARY
Enhanced Stitch Bond CapillariesENHANCED STITCH BONDABILITY
Advanced Bonding ApplicationsADVANCED BONDING APPLICATIONS
AZR Copper Bonding Capillary MaterialAZR LONG LIFE MATERIAL FOR CU WIRE BONDING
INFINITY 3X LONGER TOOL LIFEINFINITY 3X LONGER TOOL LIFE
Ball Stitch On Ball Wire Bonding CapillariesBALL STITCH ON BALL (BSOB)
Stud Ball Bumping (SBB) Bonding CapillarySTUD BALL BUMPING
Several different taper styles are available: One Side Relief, Double Side Relief, 90 Degree Double Side Relief and Vertical Bottle NeckSPECIAL CAPILLARY TAPER DESIGNS
Capillary unblocking and unplugging wireCAPILLARY UNPLUGGING WIRE (CUW)
EFO Wands for Capillary Bonding by SPTEFO WANDS
Window Clamps & Heater Block For QFP SOP & Multi-lead PackagesWINDOW CLAMPS & HEATER BLOCK
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