Rapid manufacturing of large diameter Cu micropillars by micro-electrical discharge machining and focused ion beam

Abstract

A hybrid manufacturing method consisting of micro-electrical discharge machining and focused ion beam milling to fabricate single-crystal Cu micropillars with a diameter of several tens of microns or more was proposed. The method first utilized micro-electrical discharge machining, which adopted a micro-tool made of WC-Co material, to fabricate the coarse micropillars, one by one. It took approximately 70 s to fabricate each coarse micropillar. Seventy-six coarse micropillars were fabricated in the process of exploring optimum input parameters of supply voltage and capacitance value. Energy dispersive spectroscopy and electron backscatter diffraction analyses revealed that pristine Cu material could be obtained by removing only 1.2 μm of surface layer. The micropillar was finished using a focused ion beam to form a 15 μm diameter smooth micropillar with an aspect ratio of 3. The desired micropillar was produced by removing a surface layer of 6 μm or more from the side surface to avoid the micro-electrical discharge machining effect. It took approximately 2.5 h to complete the fabrication of a micropillar by stepwise annular milling. In the case of the hybrid method, it was possible to fabricate a high-quality micropillar 17 times faster than the focused ion beam only method.

This is a preview of subscription content, access via your institution.

Fig. 1
Fig. 2
Fig. 3
Fig. 4
Fig. 5
Fig. 6
Fig. 7
Fig. 8
Fig. 9
Fig. 10
Fig. 11
Fig. 12

Availability of data and material

Not applicable

Code availability

Not applicable

References

  1. 1.

    Uchic MD, Dimiduk DM, Florando JN, Nix WD (2004) Sample dimensions influence strength and crystal plasticity. Science 305:986–989. https://doi.org/10.1126/science.1098993

    Article  Google Scholar 

  2. 2.

    Zhang H, Schuster BE, Wei Q, Ramesh KT (2006) The design of accurate micro-compression experiments. Scripta Mater 54:181–186. https://doi.org/10.1016/j.scriptamat.2005.06.043

    Article  Google Scholar 

  3. 3.

    Shim S, Bei H, Miller MK, Pharr GM, George EP (2009) Effects of focused ion beam milling on the compressive behavior of directionally solidified micropillars and the nanoindentation response of an electropolished surface. Acta Mater 57:503–510. https://doi.org/10.1016/j.actamat.2008.09.033

    Article  Google Scholar 

  4. 4.

    Thompson K, Lawrence D, Larson DJ, Olson JD, Kelly TF, Gorman B (2007) In situ site-specific specimen preparation for atom probe tomography. Ultramicroscopy 107:131–139. https://doi.org/10.1016/j.ultramic.2006.06.008

    Article  Google Scholar 

  5. 5.

    Takata N, Takeyasu S, Li H, Suzuki A, Kobashi M (2020) Anomalous size-dependent strength in micropillar compression deformation of commercial-purity aluminum single-crystals. Mater Sci Eng A772:138710. https://doi.org/10.1016/j.msea.2019.138710

    Article  Google Scholar 

  6. 6.

    Mu Y, Hutchinson JW, Meng WJ (2014) Micro-pillar measurements of plasticity in confined Cu thin films. Extreme Mech Lett 1:62–69 https://doi.org/10.1016/j.eml.2014.12.001

    Article  Google Scholar 

  7. 7.

    Bočan J, Tsurekawa S, Jäger A (2017) Fabrication and in situ compression testing of Mg micropillars with a nontrivial cross section: influence of micropillar geometry on mechanical properties. Mater Sci Eng A 687:337–342 https://doi.org/10.1016/j.msea.2017.01.089

    Article  Google Scholar 

  8. 8.

    AlMangour B, Yang J-M (2017) Understanding the deformation behavior of 17-4 precipitate hardenable stainless steel produced by direct metal laser sintering using micropillar compression and TEM. Int J Adv Manuf Technol 90:119–126. https://doi.org/10.1007/s00170-016-9367-9

    Article  Google Scholar 

  9. 9.

    Barnett R, Mueller S, Hiller S, Pérez-Willard F, Strickland J, Dong H (2020) Rapid production of pillar structures on the surface of single crystal CMSX-4 superalloy by femtosecond laser machining. Opt Laser Eng 127:105941. https://doi.org/10.1016/j.optlaseng.2019.105941

    Article  Google Scholar 

  10. 10.

    Chavoshi SZ, Luo X (2015) Hybrid micro-machining processes: a review. Precis Eng 41:1–23 https://doi.org/10.1016/j.precisioneng.2015.03.001

    Article  Google Scholar 

  11. 11.

    Gigax JG, Vo H (2019) Micropillar compression response of femtosecond laser-cut single crystal Cu and proton irradiated Cu. Scripta Mater 170:145–149. https://doi.org/10.1016/j.scriptamat.2019.05.004

    Article  Google Scholar 

  12. 12.

    Raju L, Hiremath SS (2016) A state-of-the-art review on micro electro-discharge machining. Proc Tech 25:1281–1288. https://doi.org/10.1016/j.protcy.2016.08.222

    Article  Google Scholar 

  13. 13.

    Keskin Y, Halkacı H, Kizil M (2006) An experimental study for determination of the effects of machining parameters on surface roughness in electrical discharge machining (EDM). Int J Adv Manuf Technol 28:1118–1121

    Article  Google Scholar 

  14. 14.

    Han F, Yamada Y, Kawakami T, Kunieda M (2006) Experimental attempts of sub-micrometer order size machining using micro-EDM. Precis Eng 30:123–131. https://doi.org/10.1016/j.precisioneng.2005.06.005

    Article  Google Scholar 

  15. 15.

    Bhattacharyya B (2015) Electrochemical micromachining for nanofabrication, MEMS and nanotechnology. Elsevier (William Andrew), UK. .

  16. 16.

    Tan TH, Yan J (2017) Atomic-scale characterization of subsurface damage and structural changes of single-crystal silicon carbide subjected to electrical discharge machining. Acta Mater 123:362–372. .

  17. 17.

    Lee PA, Kim SK, Kim BH (2018) Fabrication of micro column array by micro EDM using eccentric tool electrodes. J Kor Soc Precis Eng 35:305–310 (in Korean). https://doi.org/10.7736/KSPE.2018.35.3.305

    Article  Google Scholar 

  18. 18.

    Masuzawa T, Fujino M, Kobayashi K, Suzuki T, Kinoshita N (1985) Wire electro-discharge grinding for micro-machining. CIRP Annals 34:431–434. https://doi.org/10.1016/S0007-8506(07)61805-8

    Article  Google Scholar 

  19. 19.

    Kumar K, Batra U (2019) Fabrication of high aspect ratio WC-Co micro electrodes for μ-EDM application. Mater Today: Proc 18:2970–2976. https://doi.org/10.1016/j.matpr.2019.07.167

    Article  Google Scholar 

  20. 20.

    Pahnit S, Dan K, Mart GA (2011) An experimnetal study of microfabricated spark gaps: wear and erosion characteristics. J Micromech Microeng 11:165–174. https://doi.org/10.1088/0960-1317/11/3/302

    Article  Google Scholar 

  21. 21.

    Egashira K, Matsugasako A, Tsuchiya H, Miyazaki M (2006) Electrical discharge machining with ultralow discharge energy. Precis Eng 30:414–420. https://doi.org/10.1016/j.precisioneng.2006.01.004

    Article  Google Scholar 

  22. 22.

    Fischione PE, Williams REA, Genç A, Fraser HL, Dunin-Borkowski RE, Luysberg M, Bonifacio CS, Kovács A (2017) A small spot, inert gas, ion milling process as a complementary technique to focused ion beam specimen preparation. Microsc Microanal 23:782–793. https://doi.org/10.1017/S1431927617000514

    Article  Google Scholar 

Download references

Acknowledgements

We would like to thank Ms. Hyo-Won Jang of the National Nanofab Center for FIB milling and Editage (www.editage.co.kr) for English language editing.

Funding

This study was funded by the Kumoh National Institute of Technology.

Author information

Affiliations

Authors

Corresponding author

Correspondence to Chung-Seog Oh.

Additional information

Publisher’s note

Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.

Rights and permissions

Reprints and Permissions

About this article

Verify currency and authenticity via CrossMark

Cite this article

Lee, U.S., Kim, B.H., Kim, SM. et al. Rapid manufacturing of large diameter Cu micropillars by micro-electrical discharge machining and focused ion beam. Int J Adv Manuf Technol 113, 1153–1162 (2021). https://doi.org/10.1007/s00170-021-06699-y

Download citation

Keywords

  • Focused ion beam
  • Hybrid method
  • Large diameter
  • Micro-electrical discharge machining
  • Micropillar
  • Single-crystal copper