Capillary Functional Introduction

Capillary Geometry and Material Introduction

Capillary Geometry
•Main Taper Angle •Hole Size •Taper Angle •Bottleneck
•Bottleneck Taper Angle   •Chamfer Diameter  •Outer Radius

•Bottleneck height  •Chamfer Angle •Face Angle

Capillary Tip Finishing

•Matte
•Polish

Capillary material
•High Density Ceramic
•Zirconia Composite

Capillary Order by Suppliers

•SPT         • Dou Yee
•Gaiser     •K&S
•PECO

Example for Capillary Selection

Function of Capillary

1.transfer ultrasonic energy to the bond.
2.control bond ball and stitch size and shape.

Over View of Capillary Geometry

Main Geometry

Bottleneck Selection

•BNH>CLH to avoid the damage to adjacent looping, critical for fine pitch bonding.
•BNA: small enough to avoid the damage to adjacent looping, critical for fine pitch bonding.
•MTA: small MTA will provide high Ultrasonic vibration amplitude.

Tip Dimensions-Hole Size

• Hole Size

•H is determined by WD (from x1.2 for UF (Ultra Fine) pitch, to x1.5 for non-fine pitch).
•H will affect the wire feed and looping performance.
•Small H has higher risk to cause short tail, especially having scrub or smooth towards 1st bond.

Tip Dimensions-Chamfer Diameter

Chamfer Diameter

•CD <MBD/1.1
≥H+8μm or 1.2*H [std]
≥H+6μm [UF Pitch]
•CD provides volume to capture FAB.
•CD control Mashed Ball Diameter (MBD, Ball Size) and shape.

Tip Dimensions-Chamfer Angle

Chamfer Angle

•Smaller CA, better FAB centering due to larger lateral force vector which helps hold the FAB at center.
•Smaller CA, smaller MBD, good for UF pitch.

Tip Dimensions-Chamfer Angle

Chamfer Angle Effects

•Larger CA, higher US energy transfer efficiency, better IMC formation.
•Larger CA, larger tail bond strength due to larger effective tail bond area.
•Small CA has potential of sub-layer damage (cratering/peeling).
•Typical CA is 90°.

Tip Dimensions-Inner Chamfer

Inner Chamfer Type

•IC (or ICD)=(CD-H)/2
•IC condition is related to the CD and CA combination.
•Double and Radiused IC design: good for high speed and high performance looping, FAB capture, IMC formation and tail bond strength.

Dimensions Affecting Stitch Formation

Over View

•OR and FA complement each other to provide adequate thickness and smooth transition of the stitch.
•With given FA, proper combination of T and OR can provide smooth stitch transition and optimized size.

Tip Dimensions-Tip Diameter

Effects of Tip Diameter

•For non-fine pitch, T should be as large as possible to achieve long and strong stitch.
•For UF pitch, T is constrained by BPP or adjacent Ball Size.

Tip Dimensions-OR and FA Combination

Outer Radius and Face Angle

•For hard or poor-bondablilty substrate, small FA is good due to the high and even stress concentration; for soft or floating substrate, large FA can improve stitch strength and prevent cut stitch bonds.
•FA=11°for fine pitch; FA=4~8°for normal non-fine pitch.
•For given FA, OR provides a proper heel curvature of the stitch bond
to achieve adequate stitch length and minimize heel cracks.

Tip Dimensions-OR and FA Combination

OR and FA complement

•Large OR for small FA: good stitch transition, avoid neck crack.
•Small OR for large FA: produce long stitch to enhance stitch strength.

Capillary Tip Finish

Tip Finish

Capillary Materials

Bonding Impacts of Key Material Characteristics

High Density Ceramic & Zirconia Composite

•High Density Ceramic: for standard non-fine pitch application.
•Zirconia Composite: for UF pitch application

Capillary Order by Suppliers

SPT:

Source Web site: http://www.smallprecisiontools.com/

Capillary Order by Suppliers

Gaiser:

Source Web site:http://www.gaisertool.com/

Capillary Order by Suppliers

PECO：

Source Web site:http://peco.en.ec21.com/

Capillary Order by Suppliers

DOU YEE:

Source Web site:http://www.douyee.com/

Capillary Order by Suppliers

K&S:

Source Web site:http://www.kns.com/

Capillary Selection Example 1

Request Informati on

Procedure for Capillary Selection

(1)Classify the application: Ultra Fine Pitch, BGA substrate with good bondability.
(2)Determine T,H and CD: T=(BPP-Ball size/2)*2=61um; H=WD*1.2=24.5um; CD=H+6=30.5um
(3)Determine CA,FA: standard CA=90°,BGA substrate: soft and good bondability → FA=11°
(4)Determine MTA,BNA or BNH: UF pitch → BNA≤10°
(5)Determine Finish and Material: UF pitch, BGA substrate → Finish: polish; Material: Zirconia Composite

(6)Choose Capillary:

Capillary Selection Example 2

Request Informati on

Procedure for Capillary Selection

(1) Classify the application: fine pitch ball size, w/o BPP limitation, QFN substrate with poor bondability.
(2) Determine T,H and CD: H=WD*1.3=39.8um; CD≥1.2H=51.4um; CD≤MBD/1.1=59um; poor stitch bondability & no BPP limitation: T ≥120um
(3) Determine CA,FA: standard → CA=90°,BGA substrate: normal hardness substrate with poor bondability → FA=4~8°
(4)Determine MTA,BNA or BNH: no BPP, CLH limitaion → default MTA,BNA or BNH
(5)Determine Finish and Material: Cu wire → Finish: matte; Material: Zirconia Composite
(6)Choose Capillary: