Quality Engineering Development Summary Updates

By Muhammad Ruzainy Musa

Date: 2011-Feb-22

RENE CORTEZ(SPONSOR)

KAREN WOON (MENTOR)

RUZAINY

MAINTENANCE TEAM

ENGINEERING TEAM

PRODUCTION TEAM

TEAM STRUCTURE

TITLE: Quality Engineering Development Summary Updates. Mentor: Karen Woon

JULY AUG SEPT OCT NOV DEC JAN FEB 

Introduction of QA Organization Chart & QE jobs and responsibility.

 

             

QUALITY ALERT 

            

Defect Potential Assessment (DPA)               

INTERNAL QUALITY ISSUE 

            

Material review board (MRB)               

Non-conformance report (NCR)     

        

Voice of process (VOP)               

CUSTOMER COMPLAINT                

Voice of Customer (VOC) 

            

Design of experiment (DOE)               

AUDIT               

TI BOAC Fan-out         

    

MAXIM wire bond (broken stitch) Fan-out             

 

TRAINING               

TSDC - Wirebond training 

             

Problem solving technique         

    

FMEA 4th Edition       

    

 

SPC- Method 1

QUALITY ALERT

Defect Potential Assessment - FMEA Approach (Do differently)

- Receive/acknowledge- Do containment actions

- Examine the unit, it’s “failure mode & mechanism”- Generate Quality Alert OPL (with Photo of Defect & details)

- Discuss in DBS the Quality Alert issue with the Line team (Sensitize to detect it, containment, prevent escape).- Validate Containment implementation & effectiveness.

VOC Rec’d

Samples Validation

Containment 3D

Defect Potential Assessment

Root cause Validation

CAPA Validation

Voice of Customer (VOC)

• Receive complaint and provide 8D report.• Quality issue assign by Customer.• Coordinate the complaint with the respective team member within 7 calendar days.

CUSTOMER QUALITY ISSUE

SKYWORKS/ SIGE• Depress wire• Material without label and ESD bag

TIM

• Foreign Material on die• Oxide Layer Fault - Invalidate• Ball short to metal • Abnormal Mark - Invalidate• Mold flash• Package contamination

SITIME • Lifted Bond

ELMOS

• Delamination• Wafer map offset picking• Misalignment Marking• Burrs on terminals, Epoxy height - Invalidate• Top side chipping & Back side chipping

MAXIM • Broken wedge

MELEXIS • Different size tube

TAO• Color filter void - DOE• Sticky wafer ring - DOE

CUSTOMER COMPLAINT

Receive complaint

D0: Review current OCAP & FMEA

D1: Team Member

D2: Background/ FA analysis

D3: Containment Actions

D4: Fishbone analysis / Fault tree analysis

D5: Permanent corrective action plan

D6: Verification of effectiveness

D7: Prevent recurrence

D8: Congratulate team

8D Format flow

CUSTOMER COMPLAINT

Cust Ref# / Date code/ Package Problem description Root cause / finding Action taken

Carsem Reference # : ALPCML111101-1 Package type / Part description : MLPQ2.3X2.3_X1APart Date Code : 1121

Feedback from Skyworks end customer, Samsung on the SKY13397. 2 units show crushed wires that passed the original ATE test, but then failed after the customer reflow. Three SKY13397-11 devices were sent for Failure Analysis. The devices reportedly failed for having shorted VBAT to GND.

Two devices (S/N 1, S/N 2) had bond wire mechanical damage resulting in short circuit from VDD to GND on the die. The short was relieved when the devices were decapsulated and they were then normal. Device S/N 3had electrical damage (EOS) on the OUT1A transistor. The electrical damage was the closest channel to the IN1connection, indicating that there may have been EOS applied to IN1 Pin.Lot details

Carsem Lot : ALP*E-J104ZFT-01F7MES ID : S201114022002-01Device : EN13397-388LF-1Package : MLPQ2.3X2.3_X1ALot Quantity : 5560 units

Technician accidentally hit the wires of defective units when removing jammed lead-frame from machine track of wire bond.

To establish a proper lead-frame handling procedure for removing jammed lead-frame from machine track by pushing the lead-frame at bottom of lead-frame rail.Resp : BT ChongDate : 2011 Nov 21Status : Done

2. To define jammed lead-frame as critical event at wire bond operation and update in wire bond spec to alert 3rd optical operator to perform 100% inspection for the affected strip. ( QCG000013)Resp : CK YiowDate : 2011 Nov 21Status : Done

3. To study machine indexer track sensitivity to improve lead frame jam incident.Resp : DalmeetDate : 2011 Nov 25 Status : Done. Please refer attachment on the improvement study.

4. Conduct training for item 1 & 2.Resp : BT Chong/CK YiowDate : 2011 Nov 30Status : Done. Brief to all the process tech for 3 shifts.

1

2

Jammed Leadframe Improvement.ppt

Briefing List ALPCML111101-1.jpg

- Tweezer cross on the bond ball (Similar to the complaint unit)

Handling!!!

CUSTOMER COMPLAINT

SIT SIMULATION RESULT.PPT

Machine!!!

CUSTOMER COMPLAINT

Cust Ref# / Date code/ Package Problem description Root cause / finding Action taken

Carsem Reference # : ALPCML111101-1 Package type / Part description : MLPQ2.3X2.3_X1A Part Date Code / : 1121

Maxim Test feedback on lot # SDJTBBX that encountered low yield during set-up. It was only yielding 66% with contact open. Rejects were also verified valid using hand test socket. 5 sample units were submitted to FA for analysis. Out of the 5 units, 1 unit was decapsulated for internal wire dressing assessment. Broken wedge was found on this decapsulated unit.

Affected Lot Details Device/Pkg : MAX8686ETL+, 40L 6x6 TQFNFailure rate : 66%Lot numbers : SDJTBBDatecode : 1150

Combination factors which includes steep landing angle, with high end parameters and bonding sequence.

Possible – Based on the simulations results a similar signature crack on the affected pins was produced, the crack tends to further worsen and break when adjacent unit (leads with multiple bonding) are bonded.

Steep landing angle on 2nd bond1) Optimize the looping profile/parameter to minimize trajectory/landing angle. This will lessen the concentration of stress at the heel of the stitch that causes broken stitch.Responsible : BT ChongStatus : On-going (actual dies will be required)

3) To update spec ASYML3101 FMEA.Responsible : BT ChongStatus : On-going Date : Upon completion items D5.1 & D5.2.

To perform DOE plan to study and understand the steep landing angle / looping profile with relation to crack / broken wedge on lead and also to put in related controls to prevent crack / broken wedge.Responsible: Prem Chand/BT ChongStatus: On-going. DOE plan just drafted and awaiting for the arrival of dices from customer to start up. Refer the attached preliminary DOE plan as attached below. For the DOE run estimated qty required are 790 units.

Method!!!

CUSTOMER COMPLAINT

Design Of Experiment

• To involved in proactively reducing variation and eliminating defects• Formal way of maximizing information gained while resources required.• A series of structured tests are designed in which planned changes are made to the input variables of a process or system. • The effects of these changes on a pre-defined output are then assessed.TAO - color filter void

Design Of Experiment

TAO - Drop test simulation on the packaging

DOE result:

AUDIT

• Performed to ascertain the validity and reliability of information or control in the MLP line.

• Also to provide an assessment of a system’s internal control.

• Conducted several customer audit :

TIM – BOAC wafer fan-out Maxim – Broken stitch fan-out

Carsem Response

TIM – BOAC wafer fan-out

AUDIT FAN OUT ITEM

FAN OUT ACTIONSDESCRIPTION OF BEST PRACTICES Items CARSEM

(Elias / Anselm)1. Tighten Lead Placement Requirement    

Requirement - No bond allowed on half etch area. Bond must be placed on center of the effective solid part of the lead.  Actions:       

a. Sub must implement Video Lead Locator (VLL) or any equivalent lead locator feature of the bonder to improve the machine detection on the wedge placement centering during wire bond process.

1

Carsem Practise:During 1st time programing (Master recipe generated), technician need to visually confirm that the wedge placement is at the center of the lead finger.

When the golden recipe downloaded from RMS (recipe management system, the wedge placement location is limited to have 2mil tolerance for adjustment (control under parameter "bond point tolerance").

The downloaded program pattern need to be align back to the actual leadframe location using the leadframe alignment points. (Top left connection bar & Bottom right connection bar)

 

b. Sub must define the effective solid part of the lead for bonding (no half etch) per package code/leadframe type. Include actual drawing and X-ray shots.

2During setup, technician will visually confirm the wedge location located on the center of the lead.

Note: Carsem MLP is using etch leadframe, once the wedge placement is program at the center, the wedge place can be control within 1 mil.

 c. Each bonding diagram must be reviewed and revised to show effective bonding area and the correct lead placement.

3Carsem had set a guideline for the maximum wire that a lead can support / allow based on the lead length.

  d. Sub must define controls to ensure the requirement is met during machine set-up, machine repair, device change, capillary change, or when changes are made to already qualified set-up.

4For every machine set-up, device change, parameter change & capillary change, ball shear test and wire pull test are required.

2. Eliminate High Ultrasonic Power Setting at Second Bond    

Requirement - high ultrasonic power setting must be avoided to prevent micro vibration or high resonance effect to the bonds that causes bond fatigue (stitch stress marks).  

Actions:        a. Sub must review current bonding parameters and revalidate

parameters from RSM DOE performed particularly those that have high 2nd ultrasonic energy settings.

5Carsem is using Thermal Compression for all wire sizes. (on 2nd bond / Wedge bond)Bonding Temperature is 200 ± 0.5 °C

  b. RE must audit all parameters and report areas needing reoptimization to achieve reliable bonds with less ultrasonic power.

6  

 c. Submit RSM DOE plan on problem areas.

7

3. Eliminate Steep Loop Trajectory/Steep bond landing    

Requirement - Reject any stitch bond that is landing in an angle (steep loop) and will finish with more than 20 deg angle on the heel of stitch bond to prevent stress related damage . This is prone to bonds that are short.    

Actions:      

 a. Review all bonding diagrams and identify products that are susceptible to steep looping trajectory and verify actual looping trajectory. Any product what will violate requirement must be validated using actual bonding and necessary adjustment will be made accordingly.

8 DOE is on going to have the steep looping study.

  b. Review and revise assembly design rule spec and incorporate criteria for shortest wire without steep loop trajectory issue. 9 DOE is on going to have the steep looping study.

4. Revamp SPC on Wirebond Bond Pull Test    

Requirement - Change Bond Pull test procedure to include long wires, short wires, corner wires, down/ground bonds, double or multiple bonds and the wire of adjacent unit opposite them to the samples of wires to be bond pull tested.    

Actions:      

  a. Recalculate LCL and UCL and bring closer to the centerline. Redefine current SPC requirement to include OCAP on readings that drifted, failed set-up, monitors and inspection. 10

SPC show that the SPC data is within LCL and UCL for Maxim 2.0mil wire device. Carsem do have OCAP for SPC OOC situation.

5. Improve Visual Monitor to check quality of the bonds    

Requirement - Reject for any stress mark on the stitch bond. Quality monitors and set-up buy-offs must include visual inspection of the bonds. To check for quality of the stitch bond, inspection at high magnification (200X and above) is a must.    

Actions:      

  a. Reinforce SEM inspection or 200X minimum optical inspection during machine set-up, change of device, change of wire or changes to already qualified parameter setting. 11 QA do have inspection on wedge formation using

minimum 200X.

6. Implement Lead placement monitor by utilizing X-ray monitor done during mold set-up    

Requirement - Reject any bond that is placed on any part of the half etched area of the lead. Utilize the existing mold X-ray monitor that is currently in place.    

Actions:      

  a. Revise mold monitor spec to include criteria for bond placement in addition to existing criteria for wire sweeping, internal voids, etc. and frequency of monitor required. 12 Based on current monitoring, Carsem do not monitor

for lead placement. Attach are the criteria that Carsem monitor at Mold x-ray.

  b. Define Mold mold monitor - add criteria on lead placement, in addition to wiresweep, voids, etc. Update OCAP accordingly. 13

AUDIT FAN OUT ITEM

DONE ON-GOING NOT APPLICABLE WITH CONCERNS7 3 0 2 13

PROCESS FMEA CONVERSION

QA Engineering Roles:

• Coordinate with Process Engineers, Production & Maintenance to establish a Macro-Micro process flow.• Weekly meeting with team to mitigate the risk of each process step. • Target completion by end of Mac 2012.• Weekly Reporting (every Friday) by package lines / process to Quality system engineer.

• QE been assign to follow up on certain process:

PROCESS STATUS SPEC NO. REMARK

Wire bond ~ 30% ASYML3101

Molding ~ 10% ASYML4102

Pick & place ~ 90% ASYML5601

Tape attach 100% ASYML1602

Status:

Completed / Buy-Off Accepted & Released

In-Progress & within schedule / Pending for ECN approval

PROBLEM SOLVING TECHNIQUE

Identify & select problem Understand on the feedback / complaint receive Use historical data to look into the trend problem. ( Downtime, Yield, Processing time)

Understand and present situation

Identify root cause 4M method (Man, Method, Machine & Material) Fishbone diagram

Plan improvement Work out solution for potential risk Evaluate improvement actions (validation in assy line)

Execute Improvement

Confirm results

Standardize improvement Documentation (SOP / Spec) FMEA .Proliferation (Best practices are deployed)

Future plan Monitor the effectiveness of the implementation by Goal PPM / repeated issue.

TRAINING

Benefits / Gain

Analytical thinking

LeadershipTeam work/ player

Communication skills

SUMMARY

END of PRESENTATION