LETI WEEKLY STATUS REPORT

Tom McMullen

Week 7

18/3/2013 – 22/3/2013

LETI wafer thinning project flowPhase 1

ID Project Name Owner Days Start End 3-Feb 10-Feb 17-Feb 24-Feb 3-Mar 10-Mar 17-Mar 24-Mar 31-Mar 5-Apr 12-Apr 19-Apr 26-Apr

1.0 Thin Wafer Assemblies T. McMullen 0 1-Feb 30-Sep

Week 1 Week 2 Week 3 Week 4 Week 5 Week 6 Week 7 Week 8 Week 9        

                                     

1.1

PHASE 1 - Layout and mask production, first 2 wafers with microbumps delivered to Advacam LETI - 3D 10 1-Feb 29-Mar

LETI accpets CERN proposal

                       

1.1.1 Send gds to LETI T. McMullen 5 1-Feb 8-Feb                          

1.1.2Send 2 FEI4b wafers to LETI R. Bates 5 1-Feb 6-Feb

                         

1.1.3

Confirm step size on wafer and centre ofset variation on wafer LETI 5 1-Feb 6-Feb

                         

1.1.4Layout and mask production LETI 10 1-Feb 11-Feb

 

Deliverable 1: Microbumb

gds files

                     

1.1.4

First 2 wafers with micro bumps delivered to Advacam LETI 49 12-Feb 2-Apr

               

Deliverable 2: First 2 wafers

with micro bumps

delivered to Advacam

       

Current

Deliverable

Target not met

Action ListPhase 1 and 2

Action What Who When Comment6 Further funding for flip-chip process Rbates\Cbuttar 31/3/2013 Richard has confirmed this is all in place

7 Bow measurement set-up TMcM 31/2/2013Tool is down and negotiations are ongoing. We may need to find

an alternative

8 Sensors for flip chipping All 31/3/2013 Sensor availablilty for flip-chip process - Meeting rqd

9 Assembly probe test solution TMcM 19/3/2013 Pobe test solution for flip-chipped assemblies - yield maps

10 FEI4B probe card and probe set-up Rbates/TMcM 19/3/2013 FEI4B test solution for assembly testing yeild maps

11 Experience with FEI4A probe card set-up Rbates/TMcM 19/3/2013 FEI4A probe card set-up and testing of assemblies on Wentworth

12 Source other suppliers of wafer bow measurements TMcM 29/3/2013 FEI4A probe card set-up and testing of assemblies on Wentworth

Highlights and issues Bump gds design completed and mask delivery due end of next week

LETI are confident they will have delivered wafers to ADVACAM by deliverable date. Meeting required to discuss sensor availability for the flip-chip process

Amount of sensors for flip-chipping – good statistical analysis required for micro-bump yield – Richard and I have begun discussions on this.

IBL TDR bump spec:○ Pitch = 50um○ Bump density = 26,880 per ROIC○ Defect rate <0.0004○ ROIC thickness <200um

FEI4b Assembly testing○ FEI4b probe card required○ Test equipment/apparatus required○ Semi-auto testing solution required for assemblies

Meeting set with LETI for an update 25/3/13 Project will be lead by the new 3D manager Meeting to ensure all deliverables are understood Some technical discussions around technology run 2

○ Grinding and polishing of the wafer backside○ Discussion around whether LETI debonds the first thinning run or we do for the thermal cycling

measurements.

Highlights and issues (Cont’d) SMC FSM thermal cycling tool is out of use at the moment. I have given them dates for when the tool is

needed and asked for assurance that the tool will be ready by this time. Feedback from SMC is that they hope to have the tool running for when we require it, but have given no

guarantees as yet. Sourcing alternatives

○ Southampton only have this ability to 150mm ○ JEMFIRE is another possiblity

Masks delivered to LETI and fist 2 wafers for flip-chip with micr-pillars should be available on time.

Wafer Inventory

Wafer # Wafer ID Yield (60 chips max) Purpose Comment

1 VMB8WDH G= 34, y=17, R=8, B=1 Full thickness micro-bump test Delivered to LETI. High-yielding die. Micro-bump yeild testing on assemblies

2 V6B8WUH G= 43, y=13, R=4, B=0 Full thickness micro-bump test Delivered to LETI. High-yielding die. Micro-bump yeild testing on assemblies

3 VUAYCRH   First technology run. Run 2Received at Glasgow Wafer thinning to 100microns. Used for thermal cycling bow measurements at

SMC. Ship to LETI. Shipped to LETI

4 ABPJXGH G=28, Y=24, R=8  First technology run. Run 2Received at Glasgow Wafer thinning to 100microns. Used for thermal cycling bow measurements at

SMC. Ship to LETI. Shipped to LETI

5   Second technology run. Run 3 Wafer to be identified and delivered to glasgow

6     Second technology run. Run 3 Wafer to be identified and delivered to glasgow

7     Third technology run. Run 4 Wafer to be identified and delivered to glasgow

8     Third technology run. Run 4 Wafer to be identified and delivered to glasgow

9     Forth technology run. Run 5 Wafer to be identified and delivered to glasgow

10     Forth technology run. Run 5 Wafer to be identified and delivered to glasgow

Design proposal - Microbumps schape : round shape (32 sides) instead of octogon

- Electrical Continuity test proposed

- Sacrified dies for alignment

Bottom right corner

Bottom left corner

Proposed tests structures : - Only on 2 alignment chips- 2 Microbumps with 50µm diameter on

each metal pad 2 pads on bottom left & 2 pads on bottom right

- Test will be done directly on microbumps with microtips

Proposed tests structures : - B – pad array will be use for continuity

checks for contact between Cu pillars and aluminium pads. This will not affect the functionality of the chip.

LETI wafer thinning project flowPhase 2