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1. 8D Report Case Study
Presenter Name: Atul Rastogi
Date: 3rd October, 2012

2. Agenda / Contents
Team Identification
Problem Description
Containment
Root Cause
Corrective Actions and Verification
Prevent Reoccurrence
Summary (Congratulate the Team)
Questions

3. • Customer Sales Rep logged in issue in the Excel
tracking sheet and notified me of the issue
• Determined assembly/test location
of the unit in question and issued
transmittal to the customer to ship
the units to the responsible facility
• Communicated and discussed issue with appropriate
QRA team, specifically the team lead, in China
Returned Unit
Team Identification

4. • Identified the problem with the returned unit
• ATE testing revealed a short
• X-ray revealed that the die inside the package was not in
the correct position
• Deprocessing of the returned unit verified that the die
inside was bonded incorrectly
Decap of Returned Unit
X-ray of Returned Unit
Problem Description

5. • Identified affected lot from product marking and shipping
records
• Requested material from affected lot to be put on hold at the
customer location and in-house inventories
• Asked customer to return all unused material for disposition
• Issued 3D Report (preliminary version of the 8D Report)
Containment

6. 5Y Analysis
Root Cause 5Y Analysis

7. • Expanded 5Y analysis to dig deeper into the issue
Ishikawa Fishbone Diagram
Root Cause – Ishikawa Fishbone Diagram

8. • Man
• Suboptimal alignment of first die bond was not detected during self-
inspection
• Subsequent die bonds are based on the first die bond
• Material
• Compared die size with leadframe pad size and discovered tolerance
could be tight for the bonders
• Machine
• Reviewed bonder accuracy specs
• TOSOK – ±75µm
• STC400 – ±50µm
• Reviewed calibration records
• Verified bonder accuracy was with spec limits using 300 samples
• V/M inspection could not differentiate between die edge pad edge
• Process
• Production test duration was very short
• Extended stress could cause die to expand due to thermal expansion
Decap of Returned Unit
Root Cause Analysis

9. • Actions taken, verified, and documented immediately after
root cause analysis
• Man
• Operators were notified of the issue and were re-trained to take time to
verify self-inspection
• Remarks were added to the bonding diagram highlighting the tight
tolerance
• Shift supervisor verified that the preceding actions were implemented
and documented
• Machine
• Bonder STC500 with an accuracy of ±35µm is to be used going forward
• Remarks were added to the bonding diagram to specifically use the
STC500
• Shift supervisor verified that the preceding actions were implemented
and documented
• Implemented corrective actions on other devices with similar
die/leadframe pad size ratios
Corrective Actions

10. • Material – Requested leadframe change
• New pad size is ~2x (978µm vs. 1800µm)
• Eliminates die shift due to
bonder inaccuracy
• All 3 bonders can be used b bonder
so capacity is not an issue
• Received agreement from
SQ manager from
customer’s manufacturing
site
• Process Change Notification
was issued and approved
Prevent Reoccurrence

11. • Verified customer issue
• After initial assessment, highlighted and added visibility
to the tight die/leadframe pad tolerance
• Provided additional training to operators
• Reminders were incorporated in the bonding diagrams
• Requested change in leadframe increasing the pad size
by 2x, virtually eliminating the issue
• Closed the issue with the China team and the CSR,
thanking them for their support and moved on to the
next issue
• During this process, the customer was kept abreast of
our findings
Summary (Congratulate the Team)

12. Questions