Engineering, 2010, 2, 668-672
doi:10.4236/eng.2010.28086 Published Online August 2010 (http://www.SciRP.org/journal/eng).
Wire Bonding Using Offline Programming Method
Yeong Lee Foo, Ah Heng You, Chee Wen Chin
Faculty of Engineering and Technology, Multimedia University, Jln Ayer Keroh Lama, Melaka, Malaysia
Received February 5, 2010; revised March 22, 2010; accepted March 25, 2010
Abstract
Manual process of creating bonding diagram is known to be time consuming and error prone. In comparison,
offline programming (OLP) provides a much more viable option to reduce the wire bonding creation time
and error. OLP is available in two versions, i.e., vendor specific OLP and direct integration offline pro-
gramming (Di-OLP). Both versions utilize the bonding diagram and computer aided design data to speed up
bonding program creation. However, the newly proposed Di-OLP is more flexible as it can be used to create
bonding program for multiple machine platforms in microelectronics industry. Some special features of
Di-OLP method are presented. The application of generic OLP however, is applicable to machines that rec-
ognize ASCII text file. The user needs to know the data format accepted by machine and convert the data
accordingly to suit its application for different machine platforms. Di-OLP is also a practical method to re-
place the time consuming manual method in production line.
Keywords: Wire Bonding, Offline Programming, Computer Aided Design, Direct Integration Offline
Programming, Bondlist
1. Introduction
Semiconductor industry is moving in the trend of in-
creased integration and miniaturization. This has resu-
lted in increasing number of bond pads on a chip. These
pads will later be wire bonded to a leadframe via a pro-
cess called wire bonding [1,2]. Wire bonding process is
basically a process where interconnection between chip
and leadframe is established via thin gold wires. Wire
bond machines utilize precise control of bonding force,
ultrasonic vibration, bonding temperature and bonding
time to establish the connection between gold wire to
bond pad or leadframe. The trend of increased integra-
tion has resulted in new challenges for wire bond process;
mainly because more wires are bonded on a chip and pad
pitch has become smaller [3]. A single semiconductor
product can contain as much as 600 wires and pitch dis-
tance can be as low as 50 micron or smaller [4]. One of
the main challenges from this trend is the traditional
method to manually prepare the bonding program has
become very time consuming and error prone.
In order to carry out automatic wire bonding, a wire
bond machine requires a set of pre-program instruction.
These instructions will be saved as a wire bond program
(WBP). The WBP is also called wire bond recipe. The
WBP mainly consists of three sets of bonding instruction.
They are material handling, bonding parameter and
bonding path instruction. The material handling informa-
tion such as magazine dimension, leadframe-indexing
pitch can be keyed into machine relatively fast as in most
production floor these dimensions are standardized.
Bonding parameters on the other hand do require slightly
more effort if optimization is required. However when
proper characterization is carried out, such as grouping
of the bonding parameter by different types of bond pad
material, bonding capillary, etc, it allows user to re-use
the bond parameter when coming across the same bond-
ing condition. This will allow wire bond parameter to be
keyed into WBP with relative ease.
The standardization and characterization option, how-
ever do not apply to the bonding path component of
bonding program. Bonding path component is required
to guide bond head to the correct position during the
bonding process. Bonding path component can be repre-
sented by a set of bonding coordinates with each consists
of two points that are connected to form a representing
connectivity between bond pad and leadfinger as shown
in Figure 1. According to the conventional manual
method, every new product would require the user to
manually input all bonding path coordinates into the
bonding program one by one.
The conventional manual method of inputting bonding
coordinates into bonding program is suitable for product

Y. L. FOO ET AL. 669
Wire,
W
1
= x
b1
, y
b1
, x
w1
, y
w1
W
2
= x
b2
, y
b2
, x
w2
, y
w2
W
3
= x
b3
, y
b3
, x
w3
, y
w3
… = ……………….
… = ……………….
… = ……………….
… = ……………….
… = ……………….
… = ……………….
W
n
= x
bn
, y
bn
, x
wn
, y
wn
Figure 1. A bonding diagram and a set of bonding coor-
dinates representing bonding path component. Cross sym-
bol shows the coordinate system origin at the center of the
chip and leadframe.
with relatively low pin count (less than 48 wires). How-
ever as wire count increases and bond pitch becomes
smaller the manual bonding program preparation method
becomes very tedious and time consuming. Moreover
errors are likely to occur with this method. Errors are
likely to occur due to the fact that operator only has acc-
ess to locally enlarge image of bond pad and leadframe
during the manual bonding program preparation process.
This narrow vision makes it very difficult for operator to
recognize the exact bonding bond pad position where
bonding wire is to be placed. The risk of misplacing the
wire on the adjacent bond pad increases, as bond pad
pitch becomes smaller.
These limitations of manual bonding program creation
process have driven user and equipment vendor to ex-
plore other option, to speed up bonding program cre-
ation process and reduce human errors. The solution is
known as offline programming (OLP) method. This
method extracts the bonding coordinates from the com-
puter aided design (CAD) drawing and utilizes it to si-
multaneously program all wires [5]. It greatly reduces the
time required to create the bonding program [6-8].
2. Vendor Specific Offline Programming
Currently most machine vendors have their own version
of OLP programs. OLP is a more practical approach of
inputting coordinate into bonding program. OLP is a
concept where CAD data is directly extracted from
bonding diagram drawing. The CAD data consists of x
and y coordinates of each bonding point which is used by
OLP software to create workable wire bonding program.
The OLP method is known to speed up bonding program
creation process and improve accuracy of bond program
created [6,9]. Today, most wire bond machine vendors
have their own version of OLP programs. These vendor
specific OLP programs are usually created as add-on
features to CAD application in the market such as
AutoCAD. The application requires the engineer to con-
vert the bonding diagram drawing from *.gds (graphic
data system) format into the *.dwg (drawing) format,
dwg format is standard file format used by AutoCAD for
saving vector graphics file. AutoCAD is used to open the
bonding diagram in *.dwg format. The engineer then
selects the bonding reference points on the chip and
leadframe. The reference points will enable the machine
to create a coordinate system origin where all bonding
coordinates will be referred. Reference points also enable
machine to precisely compensate for any die placement
variations or orientation that occurs during the die-att-
ached process.
Once coordinate reference points are defined, user will
trigger the wire bond OLP procedure to extract two end
points from each line and uses it to create WBP. The
WBP created by OLP procedure can be directly loaded to
wire bond machine and allows all wires to be created in
bonding program simultaneously as shown in Figure 2.
This helps to address the problem of long programming
time associated with manual bonding program creation
process.
However, the vendor specific OLP program does have
it disadvantages. The vendor specific OLP is usually
very rigid as they only create WBP usable for specific
type of wire bond machine, as data format acceptable by
wire bond machine is different from one vendor to the
other. If a production line consists of wire bond machine
from different vendors, one must procure multiple ver-
Figure 2. OLP allows all wires to be created in bonding pro-
gram simultaneously.
Create reference system for
chip and leadframe.
Loading of computer aided
design wire coordinate to
create wire bond program.

Y. L. FOO ET AL. 670
sions of OLP softwares from different wire bond ma-
chine vendor. This will increase the implementation cost
of vendor specific OLP. The other disadvantage of ven-
dor specific OLP is, it only works on specific version of
CAD application. OLP from wire bond vendor A might
requires AutoCAD 2005 to work with, while OLP from
wire bond vendor B might requires AutoCAD 2006 to
create WBP. This means if a production line consists of
wire bond machine from different vendors, one might
need to license two or more versions of CAD software.
This would translate into additional licensing fees. The
cost of implementation and the inflexibility of vendor
specific OLP are key factors that hinder wide spread of
vendor specific OLP.
Another alternative to the vendor specific OLP is to
use the bondlist created by bonding diagram creation
software. Bondlist information can be converted into
machine recognizable format and carries out OLP. The
method on how bondlist information can be utilized for
OLP is presented in the following section. The term di-
rect integration offline programming (Di-OLP) is used to
differentiate this method from vendor specific OLP.
3. Direct Integration Offline Programming
Di-OLP involves creating bonding program from bon-
dlist data. Bondlist is a text file containing all the bond-
ing coordinates in a bonding diagram that defines the
wire connectivity. All these coordinates are referring to
the bonding diagram coordinate system origin. Although
bondlist contains all the coordinates of bonding diagram,
it cannot be directly uploaded to the machine to create
bonding program. The first reason is the coordinate sys-
tem origin for bondlist file does not match wire bond
machine coordinate system origin. Second, the data for-
mat of bondlist is different from machine recognizable
structure. Understanding of coordinate system origin of
bonding diagram and data format acceptable by machine
is important for successful implementation of Di-OLP.
Successful implementation requires bonding diagram
created to adhere to the relevant rules. Bonding diagram
must be drawn in scale 1:1, and the coordinate system
origin of all bonding co-ordinates must be referred to the
center of the chip and leadframe in Figure 2 [2,6]. Set-
ting the coordinate system origin to the center of package
enables user to easily match the bonding diagram coor-
dinate system origin to machine coordinate system origin.
The vendor specific OLP only needs the bonding dia-
gram to fulfill the first requirement. For the second re-
quirement, vendor specific OLP allows user to set coor-
dinate system origin on any location of chip and lead-
frame. Coordinates of all wires in vendor specific OLP
will be referred to the user defined coordinate system
origin.
In Di-OLP, however both conditions need to be ful-
filled. Bonding diagram must be created in scale of 1:1
and coordinates system origin of all bonding points must
be referred to the center of chip or leadframe.
First step of Di-OLP involves extraction of bondlist
from bonding diagram as shown in Figure 3. Bondlist is
a text file containing coordinates representing end points
of all lines drawn to represent wires connecting chip
bond pad to leadframe leadfinger. For bonding locations
on leadframe, coordinate system origin is at the center of
the leadframe/package drawing, thus all bonding location
coordinates are referred to this origin and no transforma-
tion effort is required. Figure 4 shows the bonding loca-
Figure 3. Example of Bondlist extraction from bonding
diagram.
Figure 4. Bonding location on leadframe is referred to coor-
dinate system origin at the center of the leadframe drawing.
Center of leadframe
PIN1 , , 5073.28, -3230.81,
PIN2 , , 5090.99, -2964.26,
PIN3 , , 5100.44, -2715.11,
PIN4 , , 5125.39, -2472.47,
PIN5 , , 5142.19, 2232.36,
In bondlist all the bonding location on the leadfin-
ger is represented by a set of x and y coordinate.

Y. L. FOO ET AL. 671
tion on leadframe is referred to coordinate system origin
at the center of the leadframe drawing. However, for
bonding coordinates on the chip, it is found that the co-
ordinate system origin is not referred to the center but
instead to the lower left corner of the chip. As a result the
data needed to be transformed to the center of package
before it can be used for Di-OLP.
Just like vendor specific OLP, Di-OLP helps to reduce
time needed to create WBP. It minimizes error such as
missing wire or misplaced wire. It also improves mach-
ine utilization as bonding program can be created offline
instead of using productive machine operation time.
Besides the advantages described earlier Di-OLP is more
flexible compared to vendor specific OLP. It utilizes
bondlist created by bonding diagram creation software.
This allows the OLP application without the need to
license for specific CAD software or updated software
version. Di-OLP will enable user who is not familiar
with CAD software to carry out OLP as bondlist text
format can be converted to machine usable and recog-
nizable data format using worksheet application. Di-OLP
is suitable for implementation in production line with
multiple machine platforms as long as machines accept
the coordinates in ASCII format. This eliminates the
needs for multiple vendor specific OLP softwares thus
reduces the cost of OLP implementation across multiple
machine platforms.
4. Transformation of Bonding System
Coordinates
4.1. Transformation from Lower Left Side of
Chip to Center of Chip
Any two-dimensional coordinate point in a Cartesian
coordinate system can be represented by x and y coordi-
nates by referring to a system origin, (0, 0). A vector can
be used to represent a point in a coordinate system, i.e.,
n
n
x
y



n
P.
When a new origin point is to be used (x, y) coordinate
point is then translated to (x’, y’) and the coordinates of
x’ and y’ refer to this new origin can be obtained using
the transformation vector. Figure 5 shows the transfor-
mation of coordinate origin from lower left corner of
chip to center of chip using vectors.
Poo’ is a vector representing the transformation of new
origin from the initial origin point. It is given by
oo'
oo'
x
y



oo'
P (1)
Thus, the new coordinate Pno’ with refer to the center
of package can be obtained by solving the following
vector equation
Figure 5. Using vector to transform coordinate origin from
lower left corner of chip to center of chip.
Pno’ = Pno  Poo’. (2)
In the matrix form, it is given as
no'no oo'
no'no oo'
x
xx
yyy

 


 

 
. (3)
With this method, a new set of coordinates can be ob-
tained by transforming the origin of all the bonding co-
ordinates from lower left corner to the center of the chip.
4.2. Transformation Due to Chip Orientation
When chip layout drawing is merged with leadframe
drawing, the chip might require to be turned to 90 to
ensure that the chip can be fitted into the island pad of
leadframe. This chip might also be turned 90, 180 or
270 if the pad one is required to be located at a pre-
defined location with reference to the leadframe. The
bondlist text file contains original coordinates from GDS
(Graphic Data System) II file that have not been trans-
formed. If the untransformed data is loaded to the ma-
chine the wire bond machine cannot interpret the coor-
dinate correctly.
The orientation transformation can be achieved by the
transformation equation.
For rotation by an angle θ counterclockwise about the
origin, the functional forms are x' = xcosθ − ysinθ and y'
= xsinθ + ycosθ as shown in Figure 6. The equations can
be written in matrix form as given below:
'cos
'sin
x
y

 

 
  sin
cos
x
y

 
 
 
(4)
By solving the matrix, it will provide the coordinates
for orientation θ in z-axis at the center of the package.
The two sets of transformation equations described
above will enable coordinates origin being transfered to
center of package and enable all coordinates being
oriented to appropriate angle. The matrix transformations
allow user to create a set of data that can be interpreted
by wire bond machine. Once the transformations are

Y. L. FOO ET AL. 672
Figure 6. A set of coordinates P being rotated in degree.
completed the data will be converted to ASCII format
recognizable by the machine. Different type of machine
is known to accept different text format. Some machines
accept data in comma delimited format while others
accept data in space delimited format. User of Di-OLP
need to understand the exact format accepted by a
particular machine type and carry out conversion of data
accordingly. These data can then be loaded to the wire
bond machine to simultaneously create all the connec-
tions required.
5. Conclusions
Manual process of creating bonding diagram is found to
be time consuming and error prone. OLP provides a
much more viable option to reduce the wire bonding
creation time and error. OLP is available in two versions,
vendor specific OLP and Di-OLP as described. Both
versions utilize the bonding diagram CAD data to speed
up bonding program creation. However, the proposed
Di-OLP is more flexible as it can be used to create
bonding program for multiple machine platforms. The
application of generic OLP however, is applicable to
machines that recognize ASCII text file. The user needs
to understand the data format accepted by machine and
converts the data in order to suit its application to
different machine platforms. Di-OLP is a more suitable
method to replace the time consuming manual method.
6. References
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logy,” 3rd Edition, Surface Technology, Kansas, 1995.
[2] S. DiBartolomeo, “Advance Packaging,” Penn Well,
Nashua, 2000.
[3] R. R. Tummala, V. Sudaram, F. Liu, G. White, S.
Bhattacharya, R. M. Pulugurtha, M. Swaminathan, J.
Laskar, N. M. Jokerst and S. Y. Chow, “High Density
Packaging in 2010 and Beyond,” IEEE International
Symposium on Electronic Materials and Packaging,
Taiwan, 2002, pp. 30-36.
[4] L Nguyen, I. Singh, C. Murray, J. Jackson, J. DeRosa and
D. Ho, “70 μm Fine Pitch Wire Bonding,” IEEE
International Electronics Manufacturing Technology
Symposium, Adelaide, 1998, pp. 394-400.
[5] T. C. Chang, R. A. Wysk and H. P. Wang, “Com-
puter-Aided Manufacturing,” 3rd Edition, Prentice Hall,
New York, 1998.
[6] S. K. Prasad, “Advanced Wire Bond Interconnection,”
Springer, Berlin, 2004.
[7] C. J. Oh, Y. J. Lee, Y. J. Han and C. S. Ahn, “A New
System for Reducing the Bonding Process Cycle Time
and Increasing the Accuracy of Bonding Diagram,” IEEE
International Conference on System, Man and Cyber-
netics, Vol. 5, 2004, pp. 4301-4305.
[8] Y. L. Foo, A. H. You and C. W. Chin, “Direct Integration
Offline Programming Method in Wire Bonding Process,”
11th International Conference on Electronic Materials
and Packaging, Taiwan, 2009, pp. 1-5.
[9] G. G. Harman, “Wire Bonding in Microelectronics Mate-
rials, Processes, Reliability and Yield,” 2nd Edition,
McGraw-Hill, New York, 1997.
y
x


P (x, y)
P’ (x’, y’)
O