USER’S
MANUAL
Wire Bonder (Model 747677E-79)
Boise State University
January, 2009
USER'S MANUAL
TABLE OF CONTENTS
Page #
1.0
1.1
GENERAL INFORMATION ...................................................................................................... 1-1
System Overview .................................................................................................................... 1-1
Figure 1 Wire bonder .......................................................................................................................... 1-1
1.2
Front Panel (See Fig. 1).......................................................................................................... 1-2
1.3
Microscope .............................................................................................................................. 1-2
1.4
Extra Tools .............................................................................................................................. 1-2
1.5
Points of Contact .................................................................................................................... 1-2
2.0
GETTING STARTED .................................................................................................................. 2-1
2.1
Attaching Spindle ................................................................................................................... 2-1
2.2
Threading Wire Feed ............................................................................................................. 2-1
2.3
Rotating the Needle ................................................................................................................ 2-1
2.4
Threading the Eyelet .............................................................................................................. 2-1
2.5
Threading Wire through Clamp ........................................................................................... 2-2
2.6
Attaching Sample to Stage ..................................................................................................... 2-2
2.7
Detailed Wire Bond Figures .................................................................................................. 2-3
3.0
BONDING PROCESS ................................................................................................................. 3-5
3.1
Programming Front Panel..................................................................................................... 3-5
3.2
Number of Bonds Setting ....................................................................................................... 3-5
3.3
Bonding Order ........................................................................................................................ 3-5
3.4
Power Setting .......................................................................................................................... 3-6
3.5
Time Setting ............................................................................................................................ 3-6
4.0
4.1
MAINTENANCE AND TROUBLESHOOTING ....................................................................... 4-7
Fixing Clogged Eyelet ............................................................................................................ 4-7
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1.0 General Information
1.0
1.0
GENERAL INFORMATION
1.1
System Overview
GENERAL INFORMATION
This tool is used to make interconnections between PCB boards and ICs. The wire bonding tool
uses ultra sonic power to bond the two. The machine bonds aluminum or gold wires ranging
from 0.0007 in. to 0.002 in. Ordering information for aluminum can be found at
www.sempck.com, ID: Alloy:1%SIAl WIRE. Gold wire can be ordered from www.kns.com,
ID:XS5775824427A055. Wire is clamped and threaded diagonally under the bonding wedge (see
Fig. 4 of section 2.7) allowing independent feeding action, but requiring front-to-back bonding
direction. The bonding tool is guided manually by the operator using hand/eye reference to bond
targets and elevations. The tool has XYZ motion capability.
Figure 1 Wire bonder
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Page 1-1
1.0 General Information
1.2
Front Panel (See Fig. 1)
There are 21 possible stitch bond capabilities. All of them can be set up through the front panel.
The front panel is used for programming the buffers and controlling the wire clamp. The front
panel’s features will be explored later in section 3 of the manual.
1.3
Microscope
There are three major parts of the microscope. The zoom knob, which is located closest to the
eye piece (see Fig. 1), is used to see the bond pads in more detail. The second knob is used to
focus. The microscope can be moved up and down to adjust the viewing angle. The light is the
last major component of the microscope and is located next to the viewing glass. You can rotate
the light around the microscope to view your sample more effectively.
1.4
Extra Tools
There should be two Allen wrenches. The small (0.025”) wrench is used to loosen the needle (see
section 2.3). The large (5”) wrench is used to mount the sample (see section 2.5). Metal tweezers
are also needed. It is best to use a pair with a fine tip. There is also a box of small pens used to
unclog the eyelet (see section 3.6)
Metal Tweezers
Large Allen
Wrench
Small Allen Wrench
Small Pens for unclogging
1.5
Points of Contact
For more information about this tool see www.westbond.com. For maintenance issues contact
Pete Miranda at PMiranda@boisestate.edu
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Page 1-2
2.0
2.0
GETTING STARTED
GETTING STARTED
Flip the Power switch on top left of the machine to the up position. There is also a microscope
light that will assist bonding. It is located around the bottom of the microscope glass. Now flip
the Torch switch up. It is located on the far left of the front panel.
2.1
Attaching Spindle
The three most common types of wire used in bonding are gold, silver and aluminum. To attach
the wire spindle simply slide the spindle over the silver roller (see Fig. 2). It is best if the wire
rolls off the top of the spindle.
2.2
Threading Wire Feed
Grab the wire 0.5 to 1mm from the end with metal tweezers. Gently feed the wire into the top
portion of the wire feed hole. It is best to use your right hand. If you are shaky use your left
hand to stabilizer your right arm. It also helps to put a white piece of paper on the stage. This
helps to give contrast between the needle, the wire and the stage. Once you can see the wire
coming out of the wire feed hole, pull the wire from the bottom.
2.3
Rotating the Needle
The needle must be rotated 180° to see the eyelet. Use the small Allen wrench to loosen the
screw (see Fig. 2). Then grab the top of the needle with tweezers and rotate. Place your finger
beneath the needle so it does not fall. Once the needle is rotated, tighten the screw. Check using
the microscope to see eyelet. If you do not see the needle, reduce your zoom. If you are fully
zoomed out and still unable to see the needle adjust the microscope up or down until you can see
the needle. Once the needle is in view, zoom in to see the eyelet. For a detailed view of needle
see figures 3 and 4.
2.4
Threading the Eyelet
This is the most challenging part of the bonding process. Grab the wire close to the end with the
metal tweezers. Make sure the end of the wire is not bent or flattened. See Fig. 5 and 6 in section
2.7 for optimal wire conditions. If the end of the wire is not straight, break the wire off above the
deformed area and try again. You can break the wire off by pulling the wire between your hands,
using your index and thumb fingers. While looking through the microscope thread the wire from
the front to back of the hole. It is best to feed the wire at 45 degree angle to the needle hole while
threading. Use your left hand to stabilize your right hand which holds the tweezers. Once the
wire is threaded, pull about 1mm of wire through from behind the needle. The needle must now
be rotated back to its initial position. Follow the direction in 2.3 to do this. When tightening the
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Page 2-1
needle, make sure there is a portion of the needle above the screw. There should be enough for
the tweezers to easily grab the needle.
2.5
Threading Wire through Clamp
Now that the needle is in its original position pull the wire toward yourself. Make sure the wire
is going in between the wire clamp. If the wire is below the clamp the needle must be unscrewed
and moved up. Once the wire is feeding through the clamp flip the Torch switch down. This
should close the wire clamp.
2.6
Attaching Sample to Stage
Make sure the bonding surface is clean. IPA followed by DI water may be helpful in cleaning
the surface, but make sure they are compatible with your device. If the surface has started to
oxide you may need to lightly scratch the surface. Make sure this will not harm your device.
Once the surface is clean you can attach your sample. The stage may be difficult to move. It has a
magnetic force with the bottom to reduce movement during bonding. Use the large Allen wrench
to loosen the adjustable clamp. Adjust the clamp so your sample fits snuggly under the spring
loaded clamp. Heat may be beneficial during bonding. Under the front panel there is a box with a
switch. Flip the switch up to add heat to the stage. Be careful the stage gets HOT. The
temperature can be adjusted with the up and down buttons. It is advised NOT to heat the
surface over 90C. It is also important to ensure that the bottom material of your sample does not
melt easily. If so, do not use heat or you will have a mess.
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2.7
Detailed Wire Bond Figures
Figure 2 Detailed Wire Bond
Figure 3 Non Threaded Needle
User’s Manual
Figure 4 Threaded Needle
Page 2-3
Figure 5 Optimal Wire Shape
Figure 6 Poor Wire Shape
Insufficient Power
Excessive Power
Optimal Power
Figure 7 Results of Different Power Settings
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3.0
3.0
BONDING PROCESS
BONDING PROCESS
To bond your wire, lightly press the tip of the needle to the desired bonding pad until you hear a
beep. To move the needle, use the lever to the right. Once you hear the beep lightly pull up on the
lever and move to the next pad. Again press the needle to the desired bond surface until you hear
the beep. This should complete your two bond interconnect. Throughout your bonding process,
you may need to experiment with the different settings and techniques to find the best process for
your device. The following are some of those settings.
3.1
Programming Front Panel
There are many settings that can be programmed. The settings can be saved within the buffer
position. To go to a different buffer setting, use the second switch from the left. To change the
settings within the buffer, flip the far right switch down. Three settings are important: number of
bonds, power settings and time settings. As you go through the settings, number of bonds is the
first setting.
3.2
Number of Bonds Setting
The number of bonds represents how many things you connect. If you connect a pad to a PCB
board you will need two bonds. In most cases the number of bonds will be two. If you need more
than two bonds use the third switch from the left. Flip up to increase the number of bonds and
down to decrease the number of bonds. If you would like to keep to bonds and move on to the
next setting flip the forth switch up again. This will move to the power setting.
3.3
Bonding Order
Be sure to always bond from front to back. This means start with the bond pad that is closest to
you then move to the 2nd closest till the final bond is the furthest from you. This is required due
to the wire feeding position.
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3.4
Power Setting
The power setting is an important setting. It is a good practice to start out at the recommended
setting which is 300. If you power is too high a small flake of wire will stick to you bond pad but
break off of the wire, see figure 7 in section 2.7. Your last bond usually has a higher power
setting than the other bonds. If the wire is not melting at all (there is no wire flakes or the wire
looks pressed at the end) increase your power.
3.5
Time Setting
30 is the recommended setting for time. In most cases more time is needed. You need more time
or power if the wire is not sticking at all to the substrate, see figure 7 in section 2.7. 100 is the
setting that works well for most material when bonding with gold. For starter see table for
reference values. It is recommended to start on the low side and increase setting if successful
bonds are not produced.
Bonding Surface
Wire Type
PCB/Device Packaging/Copper
IC Bond Pads
Gold
Power 300~450 Time 50-150
Power 300~400 Time 50~150
Aluminum
Power 300-325 Time 30-50
Power 300~325 Time 30~50
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3.0
MAINTENANCE AND TROUBLESHOOTING
4.0
MAINTENANCE AND TROUBLESHOOTING
4.1
Fixing Clogged Eyelet
If the eyelet gets clogged use the small pens in the box. You can grab the pen with you hand or
with the tweezers. It is whatever works best for you. Use the tip on the pen poke through the
eyelet. This will clear any blocked wire. Be careful to not break the pen tip in the eyelet. Once the
eyelet is clear you can rethread the wire (section 2.4).
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