• Developed A3 to reduce orientation error in Die Bonding process using FMEA and Fault tree analysis • With the Help of FMEA and Fault tree analysis developed an A3 on an 11”x17” paper that laid out entire plans • The aim was to clarify the link between true problems, root causes and countermeasures and suggest methods for improvements. • From the preliminary value stream Map, developed a Future state map and plotted an operator balance chart and cell design for the chosen design

1. Reduce the Orientation error In Die Bonding process using hybrid approach Presented by :
BACKGROUND
• Performance inconsistencies occur due to operation complexity of the processes.
• A rotation of die of less than 1◦ is required, but less than 3◦ is achieved.
• Using FMEA and fault tree a hybrid approach is proposed to improve quality of the bonding process.
CURRENT CONDITIONS
• Stage I: PR recognizes the die and collet moves towards the wafer table. When the collet is close enough,
the vacuum created in the collet as well as the impact push from the ejector cam move the die from wafer
table to collet. (Part misalignment causing rotation)
• Stage II: The bond arm rotates from the PR system to the lead frame where the die has to be attached. (die
slipping)
• Stage III: The die is positioned on the lead frame in the required position. (Problems similar to stage I)
GOALS
The goal is to reduce the orientation error of the bonded die
from less than 3◦ to less than 1◦with maximum failure rate of
5% for light emitting diode (LED).
ROOT CAUSE ANALYSIS
Metric Target Actual
Orientation Angle 1◦ 3◦
Failure Rate 5% 5%
Root Cause Countermeasures
Stage 1 die rotation detection error New improved PR algorithm
Rotational bond arm movement
error
Linear movement of bond arm
would reduce impact of stage 2
move errors
Wafer table not controlled
satisfactorily
Replace current stepper motor with
DC servo motor to control position
with the closed loop system
Wafer table position error Redesign wafer table to have a
floating structure
Irregular shape die Work with current supplier or find a
new supplier to improve quality
associated with die shape and size
ANALYSIS
• Part misalignment is identified as the main cause
problem to cause the rotation in stage I.
• The die rotation movement can cause die slipping
around the collet if the holding force is not strong enough.
• For stage III as well part misalignment causes the die to move
in the horizontal plane.
Aditya Kamble & Rohan Naik
RECOMMENDATIONS
• An early event is more important than a later event
• A repeated event is more important than a one-off event
• More critical events should be given higher priority
• The die rotation error was reduced from 3◦ to 2◦ ,but the target is to make it less than 1◦
• There was 30% reduction in die rotation and also by simplification of fault tree the process can be improved