Dan Cheng 1/13/2015 LARP Copper Plated Trace Development Update

Dan Cheng1/13/2015

LARP Copper Plated Trace DevelopmentUpdate

LARP Copper Plated Trace Development 2

Outline

1/13/2015

• Coil Trace fabrication update• Trace plating development status update since

10/2014 • Selective plating as an option


• CERN has produced traces for first 3 LARP Coils already

• CERN has two new traces, to be shipped to LBNL– LARP Coil 4, spare (LBNL)– LARP Coil 5, being wound this month

1/13/2015

CERN Trace, LARP v2 trace design


LARP Plated Trace Development Status, 10/2014

1/13/2015

• Identified three vendors last year for trace production– Two for producing copper plating on long material– One for selective copper etching and drilling

• Provided plating vendors with GTS-produced laminate with 304 SS on Apical AV– Requested 10 microns (0.0004”) of copper plating


LARP Plated Trace Development Status, 10/2014

1/13/2015

• Plating Vendor 1– Not limited by tank size (long lengths okay, manual process)– Samples were produced

• However, thickness of copper plating has not been thick enough (see additional slides material)

• Control of consistent plating thickness is also difficult in this process

• Plating Vendor 2– Concerned about process chemistry effects on polyimide

• Not likely to not be an issue—however, vendor has not worked with this material before

– Has reel to reel capabilities• But has concerns about thin nature of material—may be damaged during processing• Cross-sectional thickness of plating process may also vary (“dogbone”) from edges to

center of material– This edge buildup also will affect the plated material’s ability to be rolled up on takeup spool

w/o damage

LARP Copper Plated Trace Development 61/13/2015

Resistance and Estimated Cu Thickness

Sample # U (mV) R (m )W Rcu

(m )WCu thickness

d (mm)1 (Batch 1) 197.5 201.8 - -2 (Batch 1) 119.4 121.8 307.2 0.383 (Batch 1) 103.4 105.5 221.1 0.534 (Batch 1) 55.2 56.3 78.1 1.55 (CERN) 9.4 9.6 10.01 13.5

6 (Batch 2, Mid)

135.6 138.3 439.5 0.27

7 (Batch 2, edge)

165.5 168.9 1036 0.11

I=0.98 A

*Assuming rCu = 1.68 10-8 /W m M. Marchevsky

Within spec


Options Presented 10/2014

• LBNL still has the capability to produce SS-only traces in ~4 m lengths– Options 2 & 3 are compatible with this

• Other plating/processing vendors have indicated that size and roll processes may be a problem (Process 1 style)

• CERN is exploring long trace fabrication infrastructure (Process 1)

Process 1: Subtractive Process 2: Additive Option 3: Cu only?

Plate copper onto SS laminate

Etch circuit elements into SS laminate only

Material does not come thinner than 9 µm

Etch selectively Plate selectively Single etch process

Drill holes Drill holes Drill holes


• Vendor has been developing their process– Was provided spare HQ traces for development tests– They developed a calibrated device for measuring plating thickness on thin materials using

NDE method– Selectively plated these sample traces to a specified thickness

• Will be visiting LBNL tomorrow to show their results

1/13/2015

Selective Trace Plating Development

Process 1: Subtractive Process 2: Additive Option 3: Cu only?

Plate copper onto SS laminate

Etch circuit elements into SS laminate only

Material does not come thinner than 9 µm

Etch selectively Plate selectively Single etch process

Drill holes Drill holes Drill holes

LBNL still has this capability


Summary

1/13/2015

• LARP copper plated trace development is still in progress– Copper plating over long lengths of material have not been

satisfactory to date– Selective plating process has been developed; results to be

seen in a few days– Appears to be within our capabilities, if this works

• Work still to be developed with drilling of traces

• CERN has produced enough traces for 4-5 LARP coils– Copper plated, drilled, etc.


Additional Slides

1/13/2015


1st Copper Plating Sample Testing

M. Marchevsky


1st Plated Trace Thickness Measurements

1/13/2015

• Profilometer measure-ments performed by a laser vision machine– Copper thickness measures ~8

microns thick• However, not consistent across

surface• Assumes constant thickness of SS

laminate underneath• Does not really match with

electrical resistance measurements

• What is being measured is driven more by the material imperfections, not the plating thickness


Sample 1 Cross Section Measurements

1/13/2015

• Polished samples viewed with a Keyence VHX-1000 digital microscope– Measuring with 1000x

• Qualitative measurements can be observed, even if exact quantitative measurements cannot be confirmed– Referenced SS thickness (should be

approximately 25 µm)– Appears that polyimide thickness is

only approximately ~40 µm (should be 50 µm)

– Copper thickness is thicker than calculated thickness from resistance measurements (perhaps not uniform?)

Vendor sample 1

Copper, ~3 µm

Stainless, ~25 µmAdhesive, ~15 µm

Polyimide, ~50 µm


Sample 2 Cross Section Measurements

1/13/2015





– Copper thickness is thicker than calculated thickness from resistance measurements (perhaps not uniform?)

Vendor sample 2

Copper, <1 µm


Polyimide, ~50 µm


CERN Sample Cross Section Measurements

1/13/2015





– Copper thickness roughly matches calculated thickness from resistance measurements

CERN sample

Copper, ~10 µm


Polyimide, ~50 µm


Long trace etching/drilling development

• A third vendor was identified for the etching and drilling processes– Stated that selective etching copper and stainless

over very long lengths is well within their capabilities

• Drilling operations might be more involved; may require some development time for that.– Will send some sample copper-plated material for

them to work with before our copper plating development is complete

Documents

Dan Cheng 1/13/2015 LARP Copper Plated Trace Development Update