Unitek MICROPULL IV MP4/115 User manual

USER’S MANUAL NO. 990-180
REVISION B: July 2000
OPERATION AND MAINTENANCE MANUAL
FOR THE
MICROPULL®IV
WIRE BOND PULL TESTER
Model Stock Number
MP4/115 6-099-04
MP4/230 6-099-04-01
MP4(CE)/115 6-099-05
MP4(CE)/230 6-099-05-01

MICROPULL®IV WIRE BOND PULL TESTER
ii 990-180
Copyright © 2000, Unitek Miyachi Corporation
The engineering designs, drawings and data contained herein are the proprietary work of
UNITEK MIYACHI CORPORATION and may not be reproduced, copied, exhibited or
otherwise used without the written authorization of UNITEK MIYACHI CORPORATION.
Printed in the United States of America
Revision Record
Revision EO Date Basis of Revision
A Original publication
B 18347 6/00 Addition of CE version.

MICROPULL®IV WIRE BOND PULL TESTER
990-180 iii
FOREWORD
Thank you for purchasing a Unitek Equipment Micropull® IV Wire Bond Pull Tester
Upon receipt of your equipment, please thoroughly inspect it for shipping damage prior to its
installation. Should there be any damage, please immediately contact the shipping company to file a
claim, and notify Unitek Equipment at:
1820 South Myrtle Avenue
P.O. Box 5033
Monrovia, CA 91017-7133
Telephone: [phone]
FAX: [phone]
e-mail: [email protected]
The purpose of this manual is to supply operating and maintenance personnel with the information
needed to properly and safely operate and maintain the Micropull IV Wire Bond Pull Tester.
We have made every effort to ensure that the information in this manual is accurate and adequate.
Should questions arise, or if you have suggestions for improvement of this manual, please contact us at
the above location/numbers.
Unitek Miyachi Corporation is not responsible for any loss due to improper use of this product.

MICROPULL®IV WIRE BOND PULL TESTER
iv 990-180
SAFETY NOTES
This instruction manual describes how to operate, maintain and service the Micropull IV, and provides
instructions relating to its SAFE use. Procedures described in this manual MUST be performed, as
detailed, by QUALIFIED and TRAINED personnel.
For SAFETY, and to effectively take advantage of the full capabilities of the tester, please read these
instruction manuals before attempting to use the workstation.
Procedures other than those described in this manual or not performed as prescribed in it, may expose
personnel to electrical hazards.
After reading this manual, retain it for future reference when any questions arise regarding the proper
and SAFE operation of the tester.
Please note the following conventions used in this manual:
WARNING: Comments marked this way warn the reader of actions which, if not followed, might
result in immediate death or serious injury.
CAUTION: Comments marked this way warn the reader of actions which, if not followed, might result
in either damage to the equipment, or injury to the individual if subject to long-term exposure to the
indicated hazard.

MICROPULL®IV WIRE BOND PULL TESTER
990-180 v
CONTENTS
CHAPTER 1: Description............................................................................................................ 1-1
Section I. Features.................................................................................................................... 1-1
Section II. System Components............................................................................................... 1-2
Description.......................................................................................................................... 1-2
Electronic Control Unit................................................................................................. 1-3
Beam Drive Module...................................................................................................... 1-4
Beam Specifications............................................................................................................ 1-6
Hook Specifications............................................................................................................ 1-6
Model MPIT Insertion Tool.......................................................................................... 1-7
Software ........................................................................................................................ 1-7
RS-232C Serial Interface .............................................................................................. 1-8
Calibration Weights ...................................................................................................... 1-9
Standard Device Holder................................................................................................ 1-9
Optics ............................................................................................................................ 1-10
Controls and Indicators....................................................................................................... 1-10
Electronic Control Unit................................................................................................. 1-10
Beam Drive Module...................................................................................................... 1-14
CHAPTER 2: Getting Started .................................................................................................... 2-1
Section I. Planning for Installation .......................................................................................... 2-1
Space Requirements............................................................................................................ 2-1
Power Requirements ........................................................................................................... 2-1
Other Considerations .......................................................................................................... 2-1
Section II. Set-up ..................................................................................................................... 2-1
Incoming Inspection and Unpacking .................................................................................. 2-1
Mounting Optic Mounting Assembly ........................................................................... 2-2
Beam Module Installation............................................................................................. 2-3
Beam Module Removal ................................................................................................ 2-3
Switch and Cable Installation ....................................................................................... 2-3
Section III. Software Installation............................................................................................. 2-4
CHAPTER 3: Operating Instructions ....................................................................................... 3-1
Section I. Operating Precautions ............................................................................................. 3-1
General Operator Safety ..................................................................................................... 3-1
Section II. Preparing for Operation.......................................................................................... 3-1
Initial Operating Procedures ............................................................................................... 3-1
Installing the Hook on B10 and B100 Beam ...................................................................... 3-1
Installing the Rotatable Hook – B100R Beam.................................................................... 3-2
Setup Controls..................................................................................................................... 3-3
Beam Travel Adjust ............................................................................................................ 3-4
DOWNSTOP Adjust........................................................................................................... 3-5

MICROPULL®IV WIRE BOND PULL TESTER
vi 990-180
Zero Adjust ......................................................................................................................... 3-6
Section III. Operation Procedures............................................................................................ 3-6
Example of Non-Destruct Mode Testing............................................................................ 3-6
Example of Destructive Mode Testing ............................................................................... 3-8
Section IV. Printer Operation .................................................................................................. 3-9
Set-up and Interpreting Readouts ....................................................................................... 3-9
Non-Destruct Testing Program..................................................................................... 3-11
Destruct Testing Program ............................................................................................. 3-14
Printed Reports ............................................................................................................. 3-19
Disk Files and LOTUS 1-2-3.............................................................................................. 3-22
Suggestions ......................................................................................................................... 3-23
Program Documentation ..................................................................................................... 3-23
Reference Listing for MP4.BAS Release 1.0 ..................................................................... 3-24
CHAPTER 4: User Maintenance ............................................................................................... 4-1
Section I. Precautions .............................................................................................................. 4-1
General Operator Safety ..................................................................................................... 4-1
Section II. Operator Maintenance............................................................................................ 4-1
Calibration .......................................................................................................................... 4-1
Test Equipment Required ............................................................................................. 4-1
Preliminary.................................................................................................................... 4-2
Beam Travel Calibration............................................................................................... 4-3
Digital Measurement Circuit Calibration ..................................................................... 4-4
Calibration of the Beam Module .................................................................................. 4-4
Units Display ................................................................................................................ 4-5
Auto Zero...................................................................................................................... 4-6
Non-Destruct Test Performance ................................................................................... 4-6
Troubleshooting .................................................................................................................. 4-7
Repair.................................................................................................................................. 4-7
APPENDIX A: Specifications ..................................................................................................... A-1
APPENDIX B: Background and Reference Information ........................................................ B-1
APPENDIX C: Conversion for Different Input Voltage.......................................................... C-1

MICROPULL®IV WIRE BOND PULL TESTER
990-180 vii
ILLUSTRATIONS
Figure Title Page
1-1 Micropull IV, Major Components ................................................................................ 1-2
1-2 Nondestructive Pull Testing Reshaping the Wire Bonds.............................................. 1-5
1-3 B10 and B100 Beam ..................................................................................................... 1-6
1-4 B100R Beam and Insertion Tool .................................................................................. 1-6
1-5 1000g Beam Hook and Calibration System.................................................................. 1-6
1-6 MP4, Controls and Indicators ....................................................................................... 1-10
1-7 Rear View of MP4 ........................................................................................................ 1-13
2-1 Optic Mounting Assembly............................................................................................ 2-2
2-2 Attaching Beam Module to the Beam Arm .................................................................. 2-3
3-1 Installing Hook on B10 and B100 Beams..................................................................... 3-1
3-2 B1000 Beam.................................................................................................................. 3-2
3-3 B100R Rotatable Beam and Hook Assemblies ............................................................ 3-3
3-4 Beam Assembly Adjustments ....................................................................................... 3-4
4-1 Location of Components............................................................................................... 4-2
4-2 Servo PCB Assembly A3.............................................................................................. 4-3
4-3 Logic PCB Assembly A2.............................................................................................. 4-4
TABLES
Figure Title Page
1-1 Failure Codes ................................................................................................................ 1-3
1-2 Data Output Connector, J7, Signals.............................................................................. 1-4
1-3 Beam Specifications...................................................................................................... 1-6
1-4 Hook Specifications...................................................................................................... 1-7
1-5 Serial Interface Codes................................................................................................... 1-8
1-6 RS-232 Interface Connector, J1, Signals...................................................................... 1-9
1-7 Message Codes Understood by MP4............................................................................ 1-9
3-1 Test Limits for Non-Destruct Mode ............................................................................. 3-10
4-1 Troubleshooting Table.................................................................................................. 4-7

MICROPULL®IV WIRE BOND PULL TESTER
990-180 1-1
CHAPTER 1
DESCRIPTION
Section I: Features
The Micropull IV (herein called the MP4) is a semiautomatic machine designed to perform wire bond pull
tests in the 0.5 to 1000 gram-force range, using three interchangeable beams, at rates of up to one test per
second. The operator needs only to position the hook under the wire bond to be tested, and the MP4 will
automatically center itself and perform DESTRUCTIVE or NONDESTRUCTIVE wire bond pull tests and
display the test results, as well as transmit them to an optional RS-232C serial interface output connector.
The MP4 can automatically detect wire bond failures which occur during the test as well as excessive wire
bond loop height. This information is part of the output test data.
Bond pull tests are used routinely to evaluate and/or control the mechanical strength of wire bonds in
microcircuit devices. The bond pull test is performed by placing the microelectronic device in an
appropriate holder and positioning a hook under the wire midway between the two bonds. The hook is then
raised until the wire bond breaks (destructive pull test - DPT), or until the bond is stressed to a
predetermined value (nondestructive pull test-NDPT). The term "wire bond" commonly refers to the entire
interconnection consisting of both welds and the wire span. The term "bond" is used to identify a welded
area.
According to industry statistics, insufficient bond strength is a major cause of device failure. The intent of
the NDPT is to use a force great enough to cause weak bonds to fail, yet insufficient to damage good bonds.
Recommended values for the maximum safe forces for NDPT may be found in MIL-STD 883, Method 2011
and 2023. See Appendix B.

CHAPTER 1: SYSTEM DESCRIPTION
MICROPULL®IV WIRE BOND PULL TESTER
1-2 990-180
Section II: System Components
Description
The MP4 shown in figure 1-1, includes the Electronic Control Unit, the Beam Drive Module, Data Logging
software, the RS-232C interface and cable, a base plate, Optic Mounting Assembly, a device holder for flat
substrates, a set of calibration weights, spare fuses and this instruction manual. In addition, the user must
order a separate beam, available in 10 gram, 100 gram, or 1000 gram. Included with each beam is an
assortment of hooks, a hook insertion tool and spare lamps. Optional accessories include hooks, beams,
optics, device holders, and a serial printer.
The accuracy of the MP4 system is r2% of the reading or r2% of the beam scale, whichever is greater. For
example, the accuracy of the 10 gram beam is r0.2 grams, the 100 gram beam is r2 grams, and the 1000
gram beam is r20 grams. The conversion from grams-force to Newtons is accurate to within r2% using the
force of gravity as 981 gmxcm/sec2. The worst case error caused by the deflection of the beam is 0.4%
which is included in the system error specification. The error caused by operator misalignment of the hook
Fi
g
ure 1-1. Micro
p
ull IV
,
Ma
j
or Com
p
onents

CHAPTER 1: SYSTEM DESCRIPTION
MICROPULL®IV WIRE BOND PULL TESTER
990-180 1-3
with respect to the wire bond is less than 5% for misalignments of up to 5 degrees in either plane. The Zero
Drift is r0.3% of full scale during the first 15 minutes and negligible thereafter.
Electronic Control Unit.
The Electronic Control Unit uses a closed-loop servo system to control the vertical position and pull rate
of the Beam Module. The control unit converts the analog information received from the Beam Module
into digital data, displays the peak force, and transmits this data together with any error messages to the
optional RS-232C Interface. This Interface, which is a single board computer, is capable of transmitting
data in ASCII format to a user-supplied buffered serial printer at 1200 baud. The RS-232C interface can
also transmit and receive data, at 1200 baud, to another computer such as an IBM-XT or most other PC
compatibles.
Footswitch – The footswitch connects into the FOOTSWITCH connector on the rear of the MP4. It is
used by the operator to signal the MP4 to start the next test and, in those cases where the printer or
computer is used, process the data from the previous test. The footswitch also resets the display. If a
customer-supplied switch is used, its contacts should be single pole, normally open, and capable of
switching 125 mA peak current.
Remote Operation - the Beam Drive Module and/or the Electronic Control Unit may be removed from
the baseplate and operated while separated by as much as 6 feet. The Control Lever potentiometer may
also be replaced by a remote potentiometer or by a multiplying digital-to-analog converter. These
modifications might be necessary if the MP4 is made part of an automatic machine and/or is controlled
by an external computer.
Data Outputs – 13-line, 15 volt, positive true, BCD data is applied to the pins of an internal 50-pin
connector. There are additional data lines for the Print Command output, the Computer Busy input, and
MP4-generated Failure Code (table 1-1). The Print Command is held high for 10 milliseconds after the
operator presses the footswitch. The data in the BCD data registers is stable during this period. The
data and error code is then reset to zero and the MP4 performs the next test. An external device cannot
clear the MP4, but can inhibit or enable it by means of the Computer Busy input. The logic levels are 0
and +15 volts for logical 0 and 1, respectively.
Table 1-1. Failure Codes
Code Definition
0 No Test or Test In Process
1 No Failure in Non-Destruct Mode
2 No bond failure prior to reaching the Preset Force or a completed test in the
Destruct Mode
3 Wire bond failure during Hold Time
5 Over-range indication in Non-Destruct Mode
8 Excessive loop height. Beam hit Upstop prior to exerting the Preset Force
9 Marginal loop height. Beam hit Upstop during Hold Time
Data Output Connector, J7. The signal and pin numbers on Data Output connector, J7, located on the
logic PCB, are shown in table 1-2. In the table, A is the most significant digit and 8 is the most

CHAPTER 1: SYSTEM DESCRIPTION
MICROPULL®IV WIRE BOND PULL TESTER
1-4 990-180
significant bit in the 8, 4, 2, 1 BCD code format. A, B, C, and D are the data digits; H is the MP4
Failure Code.
When the footswitch is actuated, a +14 volt, 10 millisecond Print - Data Stable pulse appears on pin 29.
The MP4 can be inhibited from making another test by placing a +15 volt BUSY signal on pin 26. The
data on the BCD outputs are reset to zero within 10 ms after the end of the Data Stable pulse. The MP4
Failure Code Digits, pins 35 to 38, will change from zero as soon as one of the End of Test Conditions
occurs.
Table 1-2. Data Output Connector, J7, Signals
Signal Pin Signal Pin Signal Pin
Ground 1 A8, Ground 25 D2 44
Busy Input 26 B1 47 D4 45
Ground 28 B2 48 D8 46
Print-Data stable 29 B4 49 H1, Failure Code 35
Units 4 B8 50 H2 36
Decimal Point 2 C1 18 H4 37
Decimal Point 3 C2 19 H8 38
A1 22 C4 20 I2, Ground 7
A4, Ground 24 C8 21 I1,4,8 Logical 1 6,8,9
Beam Drive Module
The MP4 Beam Drive Module contains a servomotor which moves the beam arm assembly vertically
within low friction, self compensating, linear ball bearing races. Within the Beam Drive Module is a
precision potentiometer that accurately tracks the motion of the beam arm and transmits this information
back to the Electronic Control Unit. The beam arm contains five sets of mounting holes which allow the
beam height to be moved 1 inch in ¼-inch increments.
Beam Module – The beam module contains a lamp housing and a cantilevered beam that is gauged with
high output semiconductor strain gauges to measure the applied force. The output of the strain gauges is
applied to a preamplifier designed to reduce susceptibility to electrical noise. The design is such that
any beam module can be installed on any MP4 without re-calibration. Each beam, upon installation,
automatically changes the location of the decimal point and modifies the units of the PEAK FORCE
display, if necessary. The beam housing contains two dowel pins that allow easy mounting in one of
five sets of holes in the beam arm. The housing is held on the arm with a thumbscrew. Two electrical
connectors are used, one carries the output data from the beam and the other carries power to the lamp
housing. The front of the beam housing slides out to allow access to the front of the beam to facilitate
installation of the hook assembly.
Beam – The beam is a low-mass, cantilevered beam with relatively large compliance. The deflection for
full-scale output is 0.2 inch, with 20% over-range allowed in the Destruct Mode. The compliance of the
beam allows measurements that are essentially free from the influence of normal shock and vibration.
The tip of each beam is designed to accept a hook.
Model B10, B100, B1000 MIL-STD Beams - The design of the MP4 hook assembly insures the
accuracy of the measuring system. Because of constraints imposed by MIL-STD-883B and 883C, the

CHAPTER 1: SYSTEM DESCRIPTION
MICROPULL®IV WIRE BOND PULL TESTER
990-180 1-5
hook is allowed to pivot through a limited angular range in the front-to-back plane and is not allowed to
pivot from side-to-side. The MIL-STD also requires that the Non-Destruct pull should start with the
hook positioned midway between the two bonds. Assuming single level bonds, the result is that the
wire bond is reformed into an isosceles triangle wherein the pull force on each bond is equal, as shown
in figure 1-2.
Model B100R Rotatable Hook Beam - This beam has a 360 degree manually rotatable hook affixed to
the end of the beam. This design facilitates testing of long "stick-type" lead frames. The coupling
design quickly dampens any swinging motion of the hook. This beam will meet the accuracy
requirements of the MIL-STD when used with the supplied hooks, however the wire bonds are not
always reformed in accordance with the MIL-STD.
The Hook Assembly for the B10 and B100 beams is inserted into the beam using a special insertion tool
(figure 1-3). The hook assembly for the B100R consists of several parts which are assembled using a T-
handle insertion tool (figure 1-4). The hook on the 1000gf beam, figure 1-5, is attached to the bottom of
the hook shaft. The weight of the hook assembly is critical to both the operation and the accuracy of the
measuring system. Because of inertia, large massive hooks, whose weight typically exceeds 0.2 grams,
cannot meet the accuracy requirements of the MIL-STD when used at normal speeds in the 0.5 to 10 gf
pull range, on either the 10gf or 100gf beams. Hooks weighing up to 10 grams can be used on the
1000gf beam.
Figure 1-2. Nondestructive Pull Testing Reshaping the Wire Bonds
=
~= ~

CHAPTER 1: SYSTEM DESCRIPTION
MICROPULL®IV WIRE BOND PULL TESTER
1-6 990-180
Figure 1-5. 1000g Beam
Hook and Calibration
System
B
A
98 g
Shaft
for all
Largest
BH30
(Dimension
shown in
table 1-4)
Combined
holder and
1000 gram
total
Beam Specifications
Beam specifications are shown in table 1-3.
Table 1-3. Beam Specifications
Full Scale
Model
g-f N
Range (gf) Maximum
Deflection (in.)
B10 10 0.1 0.5 – 12.00 0.24
B100 100 1 1 – 120.0 0.24
B1000 1000 10 40 – 1,200 0.24
Model B100R is a manually rotatable hook version of B100
Hook Specifications
Hook specifications are shown in table 1-4.
Hook insertion tool
Hook access hole
Beam support
Beam cover
Beam access cover
Beam
Hook assembly
Fi
g
ure 1-3. B10 and B100 Beam Figure 1-4. B100R Beam and Insertion Tool
Knob assembly
Wire legs
Beam housing
Hook assembly
"T" handle
HandlesHair pin clip
"T' handle
installation tool
Bracket

CHAPTER 1: SYSTEM DESCRIPTION
MICROPULL®IV WIRE BOND PULL TESTER
990-180 1-7
Table 1-4. Hook Specifications
NOTE: Many specifications require that the hook diameter be approximately 2.5 times that
of the wire being tested.
Model Weight
(g)
Diameter
(in.)
Maximum
Pull (g-f)
Dimension A*
(in.)
Dimension B*
(in.)
Used On
BH3 0.1 0.003 20 0.007 2 B10, B100
BH5 0.1 0.005 50 0.011 2 B10, B100
BH8 0.1 0.008 125 0.015 2 B10, B100
BH12 0.1 0.012 300 0.025 ¾ B1000
BH20 0.1 0.020 850 0.040 ¾ B1000
BH30 0.1 0.030 2000 0.050 ¾ B1000
BH3R 0.1 0.003 20 0.007 2 B100R
BH5R 0.1 0.005 50 0.011 2 B100R
BH8R 0.1 0.008 125 0.015 2 B100R
* See figure 1-5
Model MPIT Insertion Tool
This tool is used to insert and remove hooks from the beams. One tool is included with each MP4.
Software
The data logging software for the MP4 can be used to interpret and format data which is provided via
the MP4’s RS-232 Printer Interface. This software is designed for both Destruct and Non-destruct
testing, The processing time is less than one second per test in either mode
The Non-destruct software counts the number of tests. And at user’s option, either prints the data for all
bonds or only for those bonds that fail and/or are not subjected to the proper pull. An option is provided
which allows the user to enter a six-digit location code to identify the location of any bond which fails.
The Destruct software records the data from all tests together with the appropriate, but optional, one
digit MIL-STD-883B Bond Failures Location Code entered by the user. At the completion of each set
of tests, the program calculates and prints the Average Pull Strength, the Standard Deviation, of the data
and the Normal Distribution Limit for the individual device. At the user’s option a histogram of any
device, or group of devices, can be printed.
The program includes an input screen to collect information that can be used as a heading for the
reports. A user option allow the test data to be copied to a disk file in the Lotus “.PRN” format which
can be imported into Lotus Development Corporation’s Lotus 1-2-3®Release 2. In the Destruct Mode,
the user can elect to omit printing the data, provided that an election is made to copy the data to a disk
file.

CHAPTER 1: SYSTEM DESCRIPTION
MICROPULL®IV WIRE BOND PULL TESTER
1-8 990-180
The MP4 Data Logging Software is intended to provide a general purpose, “plain vanilla” method of
data collection. Source code is provided which should allow the user to make any necessary
modifications. The program is supplied in three formats, on a 5-1/4 inch, unprotected, PC/MS-DOS
compatible diskette. MP4.BAS is a n interpreted BASIC program which has been tested, using IBM
PC-DOS Version 3.21, with BASICA Version 3.2, and Microsoft MS-DOS Version 3.21, with
GWBASIC Version for MP4.EXE which was compiles using Microsoft Corportiaion’s QuickBASIC ®
Version 4.0. Templates named NONDEST.WK1 and DESTRUCT.WK1, are used to import the “.PRN”
files generated by the MP4 software into Lotus 1-2-3.
The system hardware requirements are: an IBM PC, or most compatibles, with a minimum of 256K
RAM and two disk drives, one of which is a hard drive. The system must have an Asynchronous
Communications Adapter, equipped with a male DB-25 connector., capable of operating at 1200 baud.
Our experience indicates that the cursor keypad on the “5151” type keyboard works as expected. The
cursor pad on the enhanced IBM AT style keyboard does not function properly. This software requires
a printer whose instruction set is IBM compatible.
RS-232C Serial Interface
This interface is a single-board computer that converts the information, presented as parallel data on the
Data Output connector, to 1200 baud, ASCII coded, serial data, available on an RS-232C connector on
the rear of the MP4. The RS232C interface inserts the decimal point into the correct position in the
data. This interface is capable of driving a serial-buffered printer or communicating with an external
computer. Data resulting from each test is transmitted while the MP4 performs the next test. The actual
transmission consists of ten bit characters sent serially. Each character has one start bit, eight ASCII
coded data bits, and one stop bit. The communication is bi-directional and asynchronous, but flows in
one direction at a time. This is commonly referred to as Half Duplex Communication. The codes, listed
in table 1-5, are generated by the MP4, converted to the corresponding message by the single-board
computer, and connected to the RS-232C Connector.
Table 1-5. Serial Interface Codes
Code Message
0 No test
1 Valid test
2 Wire broke
3 Wire broke/Hold time
5 Over range
8 Hit Upstop
9 Hit Upstop/Hold time
– False error X (Where X = 4,6,7,10,11,12,13,14,15)
Random False Errors are caused by touching the hook during a test or by the hook hitting the substrate.
The False Error Message number is helpful when troubleshooting the RS-232C board.
The pin connections on the RS-232 printer/computer connector are such that the MP4 receives data on
pin 2 and transmits data on pin 3. This means that an external Null Modem is not required to transmit
data to either a printer or computer.

CHAPTER 1: SYSTEM DESCRIPTION
MICROPULL®IV WIRE BOND PULL TESTER
990-180 1-9
The signal and pin numbers for J1, the RS-232C Interface connector, are shown in table 1-6.
Table 1-6. RS-232 Interface Connector, J1, Signals
Pin Description
2 Received data
3 Transmitted data
7 Signal ground
The MP4 can understand the eight-bit binary-coded messages shown in table 1-7.
Table 1-7. Message Codes Understood by MP4
Binary Code Response by MP4
196 Disables the footswitch. Colon will light.
197 Enables the footswitch. Colon will go out.
212 Current Peak Force reading and message will be transmitted.
The MP4 includes a 4-foot long RS-232 extension cable, with DB25 male connectors, used to connect
the MP4 to either a serial printer or the RS-232C serial port of a computer.
Calibration Weights
A set of uncertified calibration weights is supplied with the MP4. When used carefully, with the weight
hanger supplied, they provide an effective method of re-calibration. The weights supplied with the MP4
are: 1, 2, 5, 10, 20, 50 and 100 grams. A weight hanger and a 300 and a 500 gram weight are supplied
with the 1000gf beam. The weight rack, which is supplied, provides a convenient method for storing the
weights. These uncertified weights are within 1/4% of the weight indicated.
Standard Device Holder
The Model DHF device holder, included with each MP4, is designed for flat substrates which range
from 1/4 to 2 inches square. The base of the device holder is spring loaded so that it can be manually
depressed up to 1/4 inch. This feature allows easy removal of the hook from deep packages. The
overall size of this device holder is 3 inches (7.6 cm) diameter by 2.375 inches (6 cm) high.
In additional to the standard device holder, the following optional device holders may be ordered:
a Model DHD device holder, with spring-loaded base, is designed for 0.3 to 0.6 inch wide side-brazed
or 0.250 inch wide CERDIP packages with lengths up to 2.070 inch.
b Model DHL device holder is designed for lead frames which have eight to 40 leads.
Optics
An optional stereo zoom optic may also be ordered. The unit has 0.7 – 3x magnification, with 20x
eyepiece and a 0.5 object lens. The optic includes the arm and porthole assembly.

CHAPTER 1: SYSTEM DESCRIPTION
MICROPULL®IV WIRE BOND PULL TESTER
1-10 990-180
Controls and Indicators
The operator controls and indicators are shown in figures 1-6 (front view) and 1-7 (rear view), and
described below.
Electronic Control Unit
POWER Switch (figure 1-6) – The POWER switch controls both sides of the incoming power line.
Control Lever – This control changes the vertical position of the hook. A closed-loop servo system
insures that the movement of the hook accurately tracks the movement of the Control Lever.
PEAK FORCE Display – This is a 3½-digit, 0.3-inch-high, light emitting diode (LED) display. The
rear panel UNITS switch (see below) selects the unit of measurement as grams- force or millinewtons
for the 10 and 100gf beams and grams-force or newtons for the 1000gf beam. The selected unit of
measurement is displayed to the right of the reading.
Measuring Rate – In the Non-Destruct Mode, the measurement rate is 100 microseconds per bit, or
approximately 100 milliseconds for a full scale input. In the Destruct Mode, the measurement rate is
120 milliseconds per bit.
Figure 1-6. MP4, Controls and Indicators

CHAPTER 1: SYSTEM DESCRIPTION
MICROPULL®IV WIRE BOND PULL TESTER
990-180 1-11
Negative Tare Indicator – This is a minus sign to the left of the PEAK FORCE display. This error
condition will be displayed for negative inputs which exceed 0.1% of full scale.
Computer Busy Indicator - A colon lights to the left of the PEAK FORCE display if the MP4 is
inhibited from further operation as a result of receiving the appropriate message, via the RS-232C
interface, from an external source. A printer cannot inhibit the MP4. The Computer Busy feature
prevents data from being lost before it is recorded by the data logging system.
MODE Switch - In the DESTRUCT position, force is applied until either the wire bond breaks or the
beam reaches the Upstop. The maximum peak force applied by the hook will be displayed until reset.
The MP4 is designed to detect wire bond failures that occur between 4% and 120% of full scale, as
defined in table 1-3. In the NON-DESTRUCT position, the pull force is preset, in 0.1% of full scale
increments, by using the three decade PRESET FORCE thumbwheel switches. The minimum
guaranteed PRESET FORCE is 1% of full scale or 0.5 gf, whichever is greater. As required by MIL-
STD, the peak force which is actually applied to the bond is displayed by the MP4. Under some
circumstances the peak force can exceed the PRESET FORCE as a result of excessive pull speed,
inertia, or vibration from an external source. Should a wire bond fail before reaching the PRESET
FORCE, the force at which the failure occurred will be displayed.
BEAM TRAVEL Control – This control changes the movement of the beam from ¼ to ¾ inch for full
movement of the Control Lever. The ratio of the Control Lever movement to beam movement is
variable from 4.5:1 to 13:1. Device holders with height variations up to 2 inches can be accommodated
by using the five mounting positions for the Beam Module together with the DOWNSTOP control and
BEAM TRAVEL control. This control is a screwdriver adjustment to prevent inadvertent changes.
DOWNSTOP Control – This control provides a fast, convenient method to electronically adjust the
position of the Downstop. The range of adjustment is ¾ inch when the BEAM TRAVEL control is set
to MIN and is reduced to ¼ inch when the BEAM TRAVEL control is set to MAX.
UPSTOP Control – This is a ten-turn potentiometer which changes the position of the Upstop. The
resolution is 0.001 inch per minor division on the vernier dial. The red Test Status Indicator, visible at
the test site, continuously blinks if the beam reaches the Upstop. The Upstop can be set to activate in
any position between full-scale travel and approximately 0.003 inch from the location of the Downstop.
A mechanical lock is provided to prevent inadvertent changes.
HOOK RETURN Switch - the HOOK RETURN switch is set to MANUAL for testing multilevel
substrates. In this mode, the hook will remain stationary after the completion of each test. In the Non-
Destruct Mode test, the red Test Status Indicator will go out, as a signal to the operator to lower the
hook, after the PRESET FORCE is reached and the HOLD TIME expires. The hook must be lowered to
the desired level by using the Control Lever. The hook cannot be raised until the operator actuates the
footswitch, which in turn lights the red Test Status Indicator. After a test, the footswitch is inhibited
until the applied pull force has been reduced by at least 5%, by lowering the hook. This feature prevents
the operator from accidentally subjecting a bond to multiple tests. When the HOOK RETURN switch is
set to MANUAL, the rear panel ZERO switch (see below) should be set to MAN (in the out position).
Otherwise if the operator should press the footswitch before the force on the hook is completely
removed, the force would be considered as tare and would be added to the force applied during the next
test.

CHAPTER 1: SYSTEM DESCRIPTION
MICROPULL®IV WIRE BOND PULL TESTER
1-12 990-180
End-Of-Test Conditions – When the HOOK RETURN switch is set to AUTO, the hook
automatically slews to the Downstop in the event any of the following end-of-test conditions occur:
1 A bond failure.
2 The PRESET FORCE is reached and the HOLD TIME expires.
3The Beam hit the Upstop.4 The MP4 MODE switch is in the NON-DESTRUCT position
and the force reaches 100% of full scale.
FT SW (Footswitch) ENABLE Switch – This momentary-action, spring-loaded switch returns control
of the MP4 to the operator in the absence of a completed test, as defined by one of the four End-Of-Test
Conditions.
ILLUMINATION Control – This control changes the intensity of the test site lighting.
RS-232C Mode (PRINTER/CMPTR) Switch (figure 1-7)– This switch selects communications with a
PRINTER (out) or the CMPTR (computer) (in).
PULL RATE Adjustment – This control adjusts the pull rate from 0.0115 inch/sec. to 0.115
inch/sec,.±20%. This is equivalent to 5% to 57% of the full-scale force per second. The upward speed
of the beam cannot exceed the preset MAX PULL RATE. When the force on the wire bond approaches
95% of the PRESET FORCE, the PULL RATE is automatically reduced to 5% of full-scale-per-second
in order to minimize, and in most cases, eliminate overshoot. The beam moves down at a fixed rate of
0.5 inches/second. Movement in either direction may be inhibited by use of the Control Lever unless
one of the four End Of Test Conditions, described above, occurred. The repeatability of the PULL
RATE is ±2%.
HOLD TIME Adjustment – Hold time is the length of time for which the PRESET FORCE is applied
to the wire bond. This control is used to adjust that time, when operating in the Non-Destruct Mode,
from 0.1 to 3 seconds, ±20%. Although this feature is active in both the Automatic and Manual Hook
Return Mode, its meaning is insignificant in the Manual Mode as the operator manually returns the
hook. A wire bond failure during the hold time is indicated by a unique message which can be recorded
using the optional RS-232C interface. Repeatability is ±2%. HOLD TIME is useful when performing
peel tests. It should be set to MIN for all other tests.
ZERO Mode Switch - In the MAN (manual) position (out), positive tare is displayed at the beginning
of each test. In the AUTO position (in), any positive tare is automatically subtracted from all readings.
The MP4 does not recognize negative inputs and, therefore, cannot compensate for them. The ZERO
switch should not be set for AUTO (in) when the HOOK RETURN switch (above) is set to the
MANUAL position.
UNITS Switch – The UNITS switch selects the unit of measurement as grams-force (gmf) (in) or
newtons (N) (out) (for the 1000gf beam) or millinewtons (for the 10 and 100gf beams). The selected
unit of measurement is displayed to the right of the PEAK FORCE indicator (above) reading.