The 60 th  ECTC  Paris Las Vegas, Nevada,  June 1 - 4, 2010 Investigation of Chemical De-burring and Subsequent Plasma Cle...
Acknowledgements <ul><li>The National Science Foundation </li></ul><ul><li>wi Spry Inc., Irvine, CA </li></ul><ul><li>High...
<ul><li>Need for a  </li></ul><ul><ul><li>Cost effective way  of micro via fabrication </li></ul></ul><ul><ul><li>High spe...
How The Punching System Works? Chowdhury ,   Li Sun, Shawn, and Ajay  µ -Via Fabrication by Mechanical Punching: Die Bushi...
Driver Applications: Chowdhury ,   Li Sun, Shawn, and Ajay  Ref:http://www.mpdigest.com/issue/Articles/2009/june/mmic/Defa...
Dealing with the Fabrication Issues Chowdhury ,   Li Sun, Shawn, and Ajay  <ul><li>Z-axis expansion of the LCP Film </li><...
Addressing the Issues Chowdhury ,   Li Sun, Shawn, and Ajay  <ul><li>By Wet Chemical Etching </li></ul><ul><ul><li>Anisotr...
Chemical Etching  Using  Ethanolamine Chowdhury ,   Li Sun, Shawn, and Ajay  <ul><li>Molecular Formula: C 2 H 7 NO </li></...
Chemical Etching  Using  Promoters <ul><li>The LCP burr need to be functionalized before it can be etched out </li></ul><u...
Chemical Etching  Using Promoters Chowdhury ,   Li Sun, Shawn, and Ajay  75 µm Via, 187.5 µm Pitch, 10 x 10 Array PROMOTER...
Chemical Etching  – Process Conditions <ul><li>2.5 Liter of Promoter A & B were taken in a beaker to submerge the 5” LCP w...
Chemical Etching  Using  Promoters Chowdhury ,   Li Sun, Shawn, and Ajay  <ul><li>PROMOTER   3308A (20 – 40 % NaMnO 4 ) @ ...
Chemical Etching  Using  Promoters Chowdhury ,   Li Sun, Shawn, and Ajay  <ul><li>PROMOTER   3308A (20 – 40 % NaMnO 4 ) @ ...
Chemical Etching  Using  Promoters Chowdhury ,   Li Sun, Shawn, and Ajay  <ul><li>Delamination due to longer etching time ...
Chemical Etching  Using  Promoters Chowdhury ,   Li Sun, Shawn, and Ajay  <ul><li>Delamination due to higher processing te...
Issue to Overcome after Chemical Etching Chowdhury ,   Li Sun, Shawn, and Ajay  <ul><li>Carbonated LCP debris leftover aft...
O 2  Plasma Cleaning of LCP Debris <ul><li>Micro vias were cleaned by using 5 Min Promoter A (NaMnO 4 ) – 5 Min Promoter B...
05 minute oxygen  plasma cleaning Chowdhury ,   Li Sun, Shawn, and Ajay  O 2  Plasma Cleaning after Chemical Etching <ul><...
Chowdhury ,   Li Sun, Shawn, and Ajay  15 minute oxygen  plasma cleaning O 2  Plasma Cleaning after Chemical Etching <ul><...
Chowdhury ,   Li Sun, Shawn, and Ajay  O 2  Plasma Cleaning after Chemical Etching 30 minute oxygen  plasma cleaning <ul><...
Chowdhury ,   Li Sun, Shawn, and Ajay  30 minute oxygen  plasma cleaning O 2  Plasma Cleaning after Chemical Etching <ul><...
Chowdhury ,   Li Sun, Shawn, and Ajay  O 2  Plasma Cleaning  Without Chemical Etching <ul><li>No improvement on the LCP an...
Summary of  µ- Via fabrication Micro via fabrication by mechanical punching 5 Minutes Oxidation of the LCP burr by 20 –  4...
Conclusions <ul><li>Ethanolamine with KOH is not a good chemistry to address the burr elimination </li></ul><ul><li>NaKMnO...
<ul><li>Thank You! </li></ul>Chowdhury ,   Li Sun, Shawn, and Ajay
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60th Ectc Presentation Chowdhury, Mohammad Kamruzzaman

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This chemical etching process to de-burr LCP is developed by me and was presented at ECTC 2010.

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60th Ectc Presentation Chowdhury, Mohammad Kamruzzaman

  1. 1. The 60 th ECTC Paris Las Vegas, Nevada, June 1 - 4, 2010 Investigation of Chemical De-burring and Subsequent Plasma Cleaning of Mechanically Punched Micro Via Array Fabricated in LCP Substrate Mohammad K. Chowdhury , 1 Li Sun, 2 Shawn Cunningham, 2 and Ajay P. Malshe 1* 1 Materials and Manufacturing Research Laboratories (MMRL) University of Arkansas, Fayetteville, AR 72701 2 WiSpry Inc., Irvine, CA 92618 * Contact: E-mail: apm2@uark.edu, Tel: (479) 575-6561, Fax: (479) 575-2669 Chowdhury , Li Sun, Shawn, and Ajay
  2. 2. Acknowledgements <ul><li>The National Science Foundation </li></ul><ul><li>wi Spry Inc., Irvine, CA </li></ul><ul><li>High Density Electronics Center (HiDEC) Staff </li></ul><ul><li>Rogers Corporation </li></ul><ul><li>Rohm and Hass </li></ul><ul><li>ECTC 2010 </li></ul>Chowdhury , Li Sun, Shawn, and Ajay
  3. 3. <ul><li>Need for a </li></ul><ul><ul><li>Cost effective way of micro via fabrication </li></ul></ul><ul><ul><li>High speed processing of through via fabrication with high yield throughput </li></ul></ul><ul><ul><li>Compatible process with the conventional via fabrication tool </li></ul></ul><ul><ul><li>E limination of thermo processing of the substrate during through via fabrication </li></ul></ul><ul><ul><li>Fabrication of vias with uniform through via wall </li></ul></ul>Motivations of the Research: Chowdhury , Li Sun, Shawn, and Ajay
  4. 4. How The Punching System Works? Chowdhury , Li Sun, Shawn, and Ajay µ -Via Fabrication by Mechanical Punching: Die Bushing Pin LCP Copper Copper LCP Copper Copper Before Punching Copper Copper LCP After Punching APS 8718 Automatic Punching System Pacific Trinetics Corporation 6” x 6” Sample Holder Punch Pin Holder & Die Bushing LCP Copper Copper LCP Copper Copper Copper Copper LCP Figure: Uniform and nice via formation
  5. 5. Driver Applications: Chowdhury , Li Sun, Shawn, and Ajay Ref:http://www.mpdigest.com/issue/Articles/2009/june/mmic/Default.asp In MMIC (Microwave Monolithic IC) Ref: http://www.pcdandf.com/cms/magazine/220-2009-issues In 3D Packaging & MCM Module Ref:http://www.cmst.be/projects/img9.jpg In Flexible Electronics Ref: http://www.techwear-weblog.com In Wearable Electronics www.smalltimes.com In RF-MEMS Devices in Cell Phone www.ec.europa.eu – ANASTASIA Project In Satellite and Aerospace Applications
  6. 6. Dealing with the Fabrication Issues Chowdhury , Li Sun, Shawn, and Ajay <ul><li>Z-axis expansion of the LCP Film </li></ul><ul><li>Warpage of the LCP sample </li></ul><ul><li>LCP Burr </li></ul><ul><li>Copper Burr </li></ul>Expansion Warpage 50 µm Via, 75 µm Pitch, 10 x 10 Array LCP Burr Bottom Cu Film Bottom Cu Film Copper Burr
  7. 7. Addressing the Issues Chowdhury , Li Sun, Shawn, and Ajay <ul><li>By Wet Chemical Etching </li></ul><ul><ul><li>Anisotropic </li></ul></ul><ul><ul><li>Isotropic (For LCP & Cu Burr) </li></ul></ul><ul><li>By Dry Etching </li></ul><ul><ul><li>Reactive Ion Etching ( O 2 Plasma Cleaning ) </li></ul></ul><ul><ul><li>Deep Reactive Ion Etching </li></ul></ul>Ref: http://www.emeraldinsight.com/fig/0870220101014.png Ref: http://knol.google.com/k/-/-/2ufdlj2yc019u/u4nyvf/deep-reactive-ion-etching%20(1).jpg
  8. 8. Chemical Etching Using Ethanolamine Chowdhury , Li Sun, Shawn, and Ajay <ul><li>Molecular Formula: C 2 H 7 NO </li></ul><ul><li>Chemical Structure: HO CH 2 CH 2 NH 2 </li></ul><ul><li>Physical State: Viscous Hygroscopic Liquid </li></ul><ul><li>50 µm Via, 75 µm Pitch, 10 x 10 Array </li></ul><ul><li>Chemical Property of Ethanolamine </li></ul><ul><li>Chemical Property of LCP </li></ul><ul><li>Due to its Hygroscopic nature the Ethanolamine was not an effective etchant for low moisture absorbent ULTRALAM 3850 TM LCP </li></ul>20 wt% EA + 40 wt% KOH + 40 wt% Water @ 85 0 C 3314 Neutralizer (3% H 2 SO 4 + 3% H 2 O 2 ) 1 Min 5 Min 5 Min 10 Min
  9. 9. Chemical Etching Using Promoters <ul><li>The LCP burr need to be functionalized before it can be etched out </li></ul><ul><li>Permanganate solution is a strong oxidizer can help in this process </li></ul>Chowdhury , Li Sun, Shawn, and Ajay <ul><li>Chemical Property of LCP </li></ul><ul><li>Promoter A: NaMnO 4 (Strong Oxidizer) </li></ul><ul><li>Promoter B: NaOH (Strong Etchant) </li></ul>Oxidation of the LCP burr by 20 – 40% NaMnO4 Etching of the LCP burr by < 30% NaOH 5 Minutes Neuratilzation by (3% H 2 SO 4 + 3% H 2 O 2 )
  10. 10. Chemical Etching Using Promoters Chowdhury , Li Sun, Shawn, and Ajay 75 µm Via, 187.5 µm Pitch, 10 x 10 Array PROMOTER 3308A (20 – 40 % NaMnO 4 ) @ 85 0 C PROMOTER 3308B (NaOH < 30%) @ 85 0 C 3314 Neutralizer (3% H 2 SO 4 + 3% H 2 O 2 ) 5 Min 1 Min 5 Min 5 Min 10 Min 15 Min PROMOTER 3308A (20 – 40 % NaMnO 4 ) @ 85 0 C PROMOTER 3308B (NaOH < 30%) @ 85 0 C 3314 Neutralizer (3% H 2 SO 4 + 3% H 2 O 2 ) 1 Min 5 Min 5 Min 5 Min 10 Min 15 Min PROMOTER 3308A (20 – 40 % NaMnO 4 ) @ 85 0 C PROMOTER 3308B (NaOH < 30%) @ 85 0 C 3314 Neutralizer (3% H 2 SO 4 + 3% H 2 O 2 ) 5 Min 5 Min 1 Min 5 Min 10 Min 15 Min
  11. 11. Chemical Etching – Process Conditions <ul><li>2.5 Liter of Promoter A & B were taken in a beaker to submerge the 5” LCP wafer sample </li></ul><ul><li>The solutions were continuously stirred using a magnetic stirrer </li></ul><ul><li>A solution temperature of 85 0 Cs was monitored continuously during the process for Promoter A & B </li></ul><ul><li>Top view SEM images of the same spot of the samples were taken before and after </li></ul><ul><li>The cross sectional analysis was done for the same sample after taking the SEM images </li></ul>Chowdhury , Li Sun, Shawn, and Ajay
  12. 12. Chemical Etching Using Promoters Chowdhury , Li Sun, Shawn, and Ajay <ul><li>PROMOTER 3308A (20 – 40 % NaMnO 4 ) @ 85 0 C - 5 Minutes </li></ul><ul><li>PROMOTER 3308B (NaOH < 30%) @ 85 0 C – 5 Minutes </li></ul><ul><li>3314 Neutralizer (3% H 2 SO 4 + 3% H 2 O 2 ) – 5 Minutes </li></ul><ul><li>Best recipe out of the matrices </li></ul>
  13. 13. Chemical Etching Using Promoters Chowdhury , Li Sun, Shawn, and Ajay <ul><li>PROMOTER 3308A (20 – 40 % NaMnO 4 ) @ 85 0 C - 5 Minutes </li></ul><ul><li>PROMOTER 3308B (NaOH < 30%) @ 85 0 C – 5 Minutes </li></ul><ul><li>3314 Neutralizer (3% H 2 SO 4 + 3% H 2 O 2 ) – 5 Minutes </li></ul><ul><li>Best recipe out of the matrices </li></ul>
  14. 14. Chemical Etching Using Promoters Chowdhury , Li Sun, Shawn, and Ajay <ul><li>Delamination due to longer etching time of 15 minutes </li></ul>Promoter A – 5 min , Promoter B – 15 min, Neutralization – 5 min 200 μ m 50 μ m
  15. 15. Chemical Etching Using Promoters Chowdhury , Li Sun, Shawn, and Ajay <ul><li>Delamination due to higher processing temperature (90 0 C) </li></ul>Promoter A – 1 min (90 0 C) , Promoter B – 5 min, Neutralization – 5 min After 200 μ m 50 μ m Delamination of the bottom Cu film
  16. 16. Issue to Overcome after Chemical Etching Chowdhury , Li Sun, Shawn, and Ajay <ul><li>Carbonated LCP debris leftover after chemical etching </li></ul>Carbonated LCP Debris
  17. 17. O 2 Plasma Cleaning of LCP Debris <ul><li>Micro vias were cleaned by using 5 Min Promoter A (NaMnO 4 ) – 5 Min Promoter B (NaOH), 5 Min Acid Neutralization (3% H 2 SO 4 + 3% H 2 O 2 ) </li></ul><ul><li>125 watt power at 320 miliTorr pressure with 160 sccm of oxygen flow was used </li></ul><ul><li>Samples were treated for 5 min, 15 min, and 30 minutes </li></ul><ul><li>SEM images were taken for the same spot before and after of plasma cleaning process </li></ul>Chowdhury , Li Sun, Shawn, and Ajay
  18. 18. 05 minute oxygen plasma cleaning Chowdhury , Li Sun, Shawn, and Ajay O 2 Plasma Cleaning after Chemical Etching <ul><li>Precipitation of LCP </li></ul>After After Before Before LCP precipitation
  19. 19. Chowdhury , Li Sun, Shawn, and Ajay 15 minute oxygen plasma cleaning O 2 Plasma Cleaning after Chemical Etching <ul><li>LCP debris did not get cleaned very well due to large volume of the debris </li></ul>After After Before Before
  20. 20. Chowdhury , Li Sun, Shawn, and Ajay O 2 Plasma Cleaning after Chemical Etching 30 minute oxygen plasma cleaning <ul><li>Small Precipitation of LCP debris also copper film get etched </li></ul>After After Before Before LCP Precipitation Copper Etching
  21. 21. Chowdhury , Li Sun, Shawn, and Ajay 30 minute oxygen plasma cleaning O 2 Plasma Cleaning after Chemical Etching <ul><li>Very nice uniform cleaned via fabrication after 30 minutes oxygen plasma cleaning </li></ul>Bottom Copper Layer
  22. 22. Chowdhury , Li Sun, Shawn, and Ajay O 2 Plasma Cleaning Without Chemical Etching <ul><li>No improvement on the LCP and copper burr removal process due to ignoring the chemical etching process before the plasma cleaning </li></ul>5 min 5 min 15 min 15 min 30 min 30 min
  23. 23. Summary of µ- Via fabrication Micro via fabrication by mechanical punching 5 Minutes Oxidation of the LCP burr by 20 – 40% NaMnO4 Chowdhury , Li Sun, Shawn, and Ajay 5 Minutes Etching of the LCP burr by < 30% NaOH 5 Minutes Neuratilzation by (3% H 2 SO 4 + 3% H 2 O 2 ) 30 Minutes oxygen plasma cleaning with 125 watt power at 320 mili torr pressure with 160 sccm of oxygen flow
  24. 24. Conclusions <ul><li>Ethanolamine with KOH is not a good chemistry to address the burr elimination </li></ul><ul><li>NaKMnO 4 for oxidation needed to functionalize the LCP before it can be etched by NaOH </li></ul><ul><li>Acid neutralization is needed after strong caustic solution etching </li></ul><ul><li>5 minutes oxidation, 5 minutes etching, and 5 minutes neutralization gives the best cleaned micro vias </li></ul><ul><li>Oxygen plasma cleaning is needed to remove carbonated LCP burr formation during the etching process </li></ul><ul><li>Therefore, a sequential treatments of wet chemical etching and oxygen plasma etching is need to make uniform micro via fabrication by mechanical punching technique </li></ul>Chowdhury , Li Sun, Shawn, and Ajay
  25. 25. <ul><li>Thank You! </li></ul>Chowdhury , Li Sun, Shawn, and Ajay

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