1. Charlie Young, SLACPitch Adapter Review 1/20/051 Trace Cracking Problem Pitch Adapter (PA).  2-mil Kapton.  ½ oz copper.  Nominal 150  -inch nickel, 10  -inch gold. Printed Wiring Board (PWB).  Nominal 1-mm radius. Cracked traces on PA after bonding.

2. Charlie Young, SLACPitch Adapter Review 1/20/052 History Before fall 2004.  ~25% rejection after bonding to PWB.  Criterion: < 8 broken traces. MCM production stopped for unrelated reasons. Restart in 12/04.  100% rejection after bonding.  (Almost) every trace is cracked, typically multiple cracks per trace.

3. Charlie Young, SLACPitch Adapter Review 1/20/053 Two Groups of PWB Nominal 1-mm radius. “Un-deburred” PWB. Measurement of profile. Noticed some surface irregularity. Gently abrade by hand. “Deburred” PWB.

4. Charlie Young, SLACPitch Adapter Review 1/20/054 Four Groups of Pitch Adapters SourceDateRev AParlexApr 0406 Rolled annealed, earlier MCM production BParlexSep 0406Rolled annealed CParlexNov 0408Rolled annealed DDyconexDec 0406? Electrodeposited, 3 test samples, visually superior

5. Charlie Young, SLACPitch Adapter Review 1/20/055 Minimum Bend Radius Guideline IPC-2223 guidelines.  2-mil Kapton and ½ oz copper.  No nickel or gold! “Flex to install” applicable here. Also note ultimate elongation at break of 16%. Max elongationMin Radius Dynamic Flex0.3%2.8 mm Flex to Install10%26  m Ultimate16%

6. Charlie Young, SLACPitch Adapter Review 1/20/056 Other Bend Radius Guidelines Radius at least 10x thickness.  PA thickness = 68  m.  Nominal radius = 1 mm, i.e. ~15x. Rolled annealed copper grain parallel to direction of bend.  Perpendicular in case of Parlex PA.  Dyconex is electro deposited instead of RA. Copper layer on neutral bend axis.  Not done here.  Is it possible?

7. Charlie Young, SLACPitch Adapter Review 1/20/057 Intrinsic Bend Capability Wrap PA around 1-mm aluminum form.  So far only PA Group C. Add weight until problems show up.  Hairline cracks appeared at 5.5 lbs.  Visible cracks (conductive) appeared at 6.2 lbs.  Cracks became non-conductive at 9.0 lbs. Conclude no intrinsic problems at 1-mm radius, but … More on this later

8. Charlie Young, SLACPitch Adapter Review 1/20/058 1-mm Radius Test Jig

9. Charlie Young, SLACPitch Adapter Review 1/20/059 Bend Radius Observation at Teledyne Use PWB in gluing fixture but no epoxy. Clamp one side of PA (Group C). Sweep PA over radius with “wiper blade”. No additional tension. Massive trace cracking. Inconsistent with test jig results. Trying to understand differences.

10. Charlie Young, SLACPitch Adapter Review 1/20/0510 Two Sets of Gluing Fixtures Teledyne design.  Used in all production so far.  Four almost identical fixtures.  PA stretched during operation. G&A design.  Used in a few tests.  One fixture.  PA sits in concave mold.  No pulling, hence no stretching.

11. Charlie Young, SLACPitch Adapter Review 1/20/0511 Teledyne Fixture

12. Charlie Young, SLACPitch Adapter Review 1/20/0512 Teledyne Fixture Design Flaw Stretch PA ~1.5 mm.  Clear from design drawings.  Confirmed in test. 1.5 mm / 16% = 1 cm. PA full width ~6 cm. Unrestrained part ~1 cm. Certainly contributor to low yield.

13. Charlie Young, SLACPitch Adapter Review 1/20/0513 Recent Test Results PA Group FixturePWBOutcome A1 TeledyneOK B4 TeledyneBothBad C 1 Teledyne, G&A Bad D2 TeledyneUndeburred Single crack on ~1/3 traces

14. Charlie Young, SLACPitch Adapter Review 1/20/0514 Conclusion on PWB Deburring or not is not the fundamental problem.  Similar problems using Group B PA. Poor radius may be contributing factor.

15. Charlie Young, SLACPitch Adapter Review 1/20/0515 Conclusion on PA Parlex Sep 04 and Nov 04 – no good. Parlex Apr 04 – better. Looking into what has changed. Dyconex much better than bad Parlex PA.

16. Charlie Young, SLACPitch Adapter Review 1/20/0516 Conclusion on Fixture Stretching is very bad.  1.5 mm is near ultimate elongation. Teledyne fixture only a contributing factor.  Earlier production yield ~75%.  Recent test with Apr 04 PA OK.  Problem common to all 4 fixtures. G&A fixture OK with earlier PA, but similar problems with Nov 04 PA.