1、1CHAPTER 62Bond Stick On Ball(BSOB)/Bond Ball On Stitch(BBOS)/Tail Break31.0)BOND STICK ON BALL(BSOB)1.1)DescriptionThis bonding process is specially developed by ASM to handle multi-die(MCM)bonding application.In the conventional approach,if one is trying to connect the gold wire from one die to th
2、e another,a capillary mark of second bond will be evident on top of the die which may damage the die.The BSOB process will solve this problem by bonding a ball onto the dies surface first,followed by bonding another wire where the second bonds wedge will be landing on top of this bonded ball(figure
3、1).4Die 1Die 2Bond Ball2nd Bond(wedge)1st Bond Figure 1:Bond Stick On Ball(BSOB)52.0)BOND BALL ON STITCH(BBOS)/SECURITY BOND2.1)DescriptionThis process is also known as security bond.It bonds a ball on top of the wedge of the normal connection wire.This process is mainly used to secure the second bo
4、nd sticking capability.(Figure 2)Die 1LeadBond Ball2nd Bond(wedge)1st Bond Figure 2:Bond Ball On Stitch(BBOS)63.1)Free Air Ball(FAB 2)is aligned to the center of the bond pad on device 2.Device 1Device 2FAB 23.0 STANDOFF BALL CONTROL BONDING SEQUENCE73.2)Capillary descends and bonds ball to bond pad
5、.Device 1Device 2W/clamp openCapillaryApplication of 1st bond stand off ball parameter to form Ball Thickness and Ball SizeDuring Stand Off Bonding,SOB parameters are applied.83.3)Capillary rises to loop base to clear ball.Device 1Device 2W/clamp openCapillary rises to set Loop BaseLoop BaseContact
6、Pt.Loop base is the distance between the capillary tip and contact point.Recommended setting=293.4)Capillary move to programme ball offset.Ball offset can be programmed towards or away from the first bond.+ve towards 2nd bond -ve away 2nd bond Device 1Device 2W/clamp openActual Ball Offset=Setting x
7、 10umIf Ball Offset Setting=22Then Actual Loop Base=220umRecommended Setting=-ve 35103.5)Capillary descends and forms stitch bond on top of the ball.Device 1Device 2W/clamp open*Ball ThicknessSOB Parameter (Stand Off Ball Parameter)Capillary descends to set Ball Thickness(Amt.Z movement above the ba
8、ll height)Contact Pt.*Ball Thickness is the distance between the capillary tip and contact point Recommended setting=2 113.6)Capillary moves horizontally for a scrub distance to weaken the wire at ball neck.Device 1Device 2W/clamp openScrub one direction away from ballActual Scrub Distance=Setting x
9、 0.8 umIf Scrub Distance Setting=10Then Actual Scrub Distance=8 um Capillary move to set Scrub Distance One direction ONLY-Away from the ball Recommended setting=8123.7)Capillary rises to tail heightDevice 1Device 2W/clamp closeCapillary moves to set Tail Length(Amount Z movement above the bump befo
10、re the wire clamp closes)Recommended setting=35133.8)Capillary rises and tears the wire,as BH ascend to Fire Level.Device 1Device 2W/c close143.9)EFO fires to form free air ball.Cycle repeats until all“Standoff Ball”are placed.Device 1Device 2Bond BallFAB153.10)After placing all standoff balls.The m
11、achine continue to bond wires.2nd Bond(wedge)1st Bond Device1Device2Device1Bond Ball16Bump ball formation for BSOB/BBOSMOTION BO LB BT SCNormalLBBOBTScrubFlatLBBOBTScrub=0CONELBBOBT=LBScrub=0 LB BO BT LB BOThe bump ball formation process is almost like bonding a normal wire,including 1st bond,loopin
12、g and 2nd bond parameters.174.0)PARAMETER DEFINITION IN STAND OFF BALL CONTROL MENU4.1)Loop BaseThis parameter determines the loop level of the bondhead which should be sufficient to avoid the ball.Range:Loop Base 0 5Setting:24.2)Ball OffsetThis setting controls the distance of the table move in ord
13、er to offset the capillary from the standoff ball.Negative value can be moved towards to the first bond.Positive value can be moved away from the first bond.Range:Ball Offset -40 20Setting:-ve 35 184.4)Scrub DistanceThis setting controls the capillary moves horizontally with a Scrub amplitude to wea
14、ken the wire at neck.It is always away from thefirst bond.Range:Scrub Dist 4 12Setting:84.5)Tail LengthThis setting controls the length of the tail where the bondhead rises to the preset height before the wire clamp is closed.Range:Tail Length 30 40Setting:354.3)Ball ThicknessThis parameter refer to
15、 the ball thickness which controls the level of the bondhead as it descends to the top of the ballRange:Ball Thickness 0 5Setting:2194.6)Time Base 1/2This setting controls the bond time applied to the standoff ball control only.Time 1 for the 1st bond and Time 2 for the 2nd bond.4.7)Power Base 1/2Th
16、is setting controls the ultrasonic power applied to the standoff ball control only.Power 1 for the 1st bond and Time 2 for the 2nd bond.4.8)Force Base 1/2This setting controls the bonding force applied to the standoff ball control only.Force 1 for the 1st bond and Force 2 for the 2nd bond.204.9)Stan
17、dby Power 1/2This setting controls the power activated when the bonding head reach the search level,to the moment the bond head contacts the bond surface.With the vibration,before contact take place.Bond head will clean up the pad surface and remove water vapor on the pad.This parameter used for the
18、 standoff ball control only.4.10)Contact Time 1/2Refer to the Contact time 1/2 definition in Bond Parameter menu.But this parameter will be affected on the Standoff ball control only.214.11)Contact Power 1/2Refer to the Contact Power 1/2 definition in Bond Parameter menu.But this parameter will be a
19、ffected on the Standoff ball control only.4.12)Contact Force 1/2Refer to the Contact Force 1/2 definition in Bond Parameter menu.But this parameter will be affected on the Standoff ball control only.22Figure 4:Standoff Ball Control Parameter Display(page 2)5.0 BSOB WIRE PARAMETERS235.1)Wire Offset I
20、n-MenuThis is the offset parameter that is required to ensure maximum contact area between the stitch bond and ball.It is always away from the first bond.Range:Wire Offset 10 30 Recommended setting=255.2)Second Bond Search SpeedThis Parameter controls the impact for stitch on ball.Range:Search Speed
21、 2 32 256Recommended setting=322nd Bond WedgeStand Off BallCapillary position during stitch bond245.3)Time Base 1/2This setting controls the bond time applied to the device.Time 1 for the 1st bond and Time 2 for the 2nd bond.5.4)Power Base 1/2This setting controls the ultrasonic power applied to the
22、 device.Power 1 for the 1st bond and Time 2 for the 2nd bond.5.5)Force Base 1/2This setting controls the bonding force applied to the device.Force 1 for the 1st bond and Force 2 for the 2nd bond.25Ball Parameters for BSOB and BBOS5.6 Tail LengthControls the length of the tail where the bond head ris
23、es to the preset height before the wire clamp is closedRange 15 45(*10um)26Ball Parameters for BSOB and BBOS5.7 Tail break TimeUsed to increase the wire straightness and reduce the snake wire during BSOB/BBOS applicationRange 0 -100(*0.25ms)Setting 1027Ball Parameters for BSOB and BBOS5.8 Tail Break DistanceUsed together with the tail break timeTraveling distance can be determined by the settingRange 10 50(*10um)Setting 25Tail break time and tail break distance are valid only when the wire or ball tail break map in wire parameter menu is set to“Y”.
