铜线工艺培训教材

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Cu Kit Installation Procedure
• Step 4: Fine tune x, y and z position of nozzle
Distance between capillary wall and tip of nozzle hole < 2mm.
Same or slightly higher level for e torch tip to the lower nozzle position.
New E-torch nozzle assembly
Fine Pitch: 0.5mm Pt E-torch nozzle
Super Heavy: 1mm Pt E-torch nozzle
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Copper Kit Configuration
• E-torch Nozzle Assembly and Nozzle
• Guideline of flow rate
– 0.8 to 1.0 mil wire (Fine pitch, Dual nozzle) L=0.4, R=0.2LPM
– 0.8 to 1.3mil wire (Non fine pitch, Single nozzle) R=0.4-0.6LPM
is why most power devices use copper wires instead of gold wires without affecting process performance and package reliability) – Has ductile properties that allow copper wires to be easily drawn into finer wires (that can be used for ultra fine pitch applications) – Costs less compared to that of gold wire giving as much (sometimes even better) performance as the gold wire
– Shows excellent response in ball neck formation as well as loop stability during plastic encapsulation or molding process
– More conductive than gold wire – Provides better heat dissipation and increased power ratings (that
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Copper Wire Properties
• Copper wire advantages and properties
– Possesses tensile strength and elongation characteristics that are comparable to gold wire
N2 Flow rate setting is between 0.2 L/min and 2.0 L/min for both nozzle. E-torch Nozzle Nozzle
Complete Assembly in 3D View
View from the bottom
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Copper Kit Configuration
– Adjust the z position of the Cu kit nozzle. » Note: Ensure that the cap screw is not hitting the nozzle and there is sufficient gap between the nozzle and window clamp
Fig. 3: Adjustment Top plate
– Adjust the x position according to the specification of < 2mm distance between cap wall and nozzle tip
– Adjust the y position of the nozzle until the capillary (at side view) is seen in the middle of the nozzle hole.
– N2 cabinet at room temperature (20 – 25 C) – 4 to 6 months shelf life (originally sealed package) inside the N2
cabinet – Once opened and used, consume within 2 – 3 days.
• Both shows good shear response (>6.5 g/mil2)
Gold Ball Shears within ball Copper Ball shears within Al metallization
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Copper vs Gold in Intermetallic
The tip of the capillary should be within the nozzle’s opening
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Copper Kit Configuration
• Eagle and Eagle 60 Fine Pitch and Super Heavy
– 2 nozzles located at both sides to prevent oxidation of Cu FAB during bonding
Fig. 2: Dummy cap
Dummy capillary
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Cu Kit Installation Procedure
• Step 3: Turn off BH power (Z motor)
– Lower down the transducer until capillary is touching the lowest possible contact position (i.e. DAP) refer to Fig 3
• 2 nozzle design for copper bonding
New Nozzle Configuration
N2 Blow at both sides
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Troubleshooting of Nozzle Setup
Oxidized FAB and Ball
Clean FAB and Ball
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Copper Physical Properties
Physical Characteristics of Copper, Gold and Aluminum
Au
Cu
Al
Density (g/cc)
19.3
8.92
2.71
Melting Point (°C)
1063 1083
659
Thermal Conductivity *1
0.70
0.94
0.57
Thermal Expansion *2
14.2
17.0
23.5
Electrical Resistivity *3
2.3
1.67
2.69
Units: *1 (cal/cm, °, sec); *2 (/°C x10-6); *3 (-.cm)
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Copper vs Gold in Ball Shear
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Cu Kit Installation Procedure
• Step 3a: Adjusting x, y, z position
1 x M3 screw (z axis) 1 x M3 stopper screw (z axis)
2 x M3 screws (x axis)
1 x M3 screw (y axis)
– To create a bigger area and a balance flow current of inert environment
– New E-torch nozzle assembly integrated
• E-torch integrated with nozzle to blow N2H2 on the Cu FAB
• Sparking Sequence
– Change to copper sequence in EFO Setting menu – EFO will spark just before bonding or Z start to move – It sparks above 1st bond position, gold sequence sparks at 2nd bond
Gold Ball is covered with large Intermetallic coverage
Copper Ball has very little or no Intermetallic coverage
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Copper Wire Bonding
• Wire Recommended Storage Conditions
position.
• BQM
– Always use Mode A 138kHz
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Cu Kit Installation Procedure
• Step 1: Mount the Cu kit on the BH Module
» Tighten two M3 screws with spring washer after adjusting the kit in the x direction (left/right) refer to Fig. 1
铜线工艺培训教材
ASM
Copper Wire Bonding
• Introduction to copper wire bonding
Copper wire bonding, as the name implies, uses copper wires in wire bonding technology. Copper wires, with its excellent characteristics and properties, have proved bonding results robust and comparable to that of gold wire bonding. With the recent good results and success brought about by the different evaluations and testing performed for copper wire bonding, the technology has pointed out its advantages and disadvantages in wire bonding application.
Bondhead Module
Fig.1: Cu Kit Mounting
M3 screws
Stopper Screw
Used to tighten Cu kit
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Cu Kit Installation Procedure
• Step 2: Install a dummy capillary
– A dummy capillary is preferred so as to prevent breakage during adjustment of Cu kit. refer to Fig. etup
• Before proceed bonding, must check the color and shape of FAB using stereo microscope
• If FAB oxidized or off-centered, fine adjust nozzle position, flow rate and fire level