Photo-Defined Electrically Assisted Etching Method for Metal Stencil Fabrication

Bhat, Shriram N and Rao, Anand G and Dinesh, NS and Baliga, BN (2011) Photo-Defined Electrically Assisted Etching Method for Metal Stencil Fabrication. In: IEEE Transactions on Components Packaging & Manufacturing Technology, 1 (7). pp. 1116-1121.

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Abstract

Metal stencils are well known in electronics printing application such as for dispensing solder paste for surface mounting, printing embedded passive elements in multilayer structures, etc. For microprinting applications using stencils, the print quality depends on the smoothness of the stencil aperture and its dimensional accuracy, which in turn are invariably related to the method used to manufacture the stencils. In this paper, fabrication of metal stencils using a photo-defined electrically assisted etching method is described. Apertures in the stencil were made in neutral electrolyte using three different types of impressed current, namely, dc, pulsed dc, and periodic pulse reverse (PPR). Dimensional accuracy and wall smoothness of the etched apertures in each of the current waveforms were compared. Finally, paste transfer efficiency of the stencil obtained using PPR was calculated and compared with those of a laser-cut electropolished stencil. It is observed that the stencil fabricated using current in PPR waveform has better dimensional accuracy and aperture wall smoothness than those obtained with dc and pulsed dc. From the paste transfer efficiency experiment, it is concluded that photo-defined electrically assisted etching method can provide an alternate route for fabrication of metal stencils for future microelectronics printing applications.

Item Type:	Journal Article
Publication:	IEEE Transactions on Components Packaging & Manufacturing Technology
Publisher:	IEEE
Additional Information:	Copyright 2011 IEEE. Personal use of this material is permitted.However, permission to reprint/republish this material for advertising or promotional purposes or for creating new collective works for resale or redistribution to servers or lists, or to reuse any copyrighted component of this work in other works must be obtained from the IEEE.
Keywords:	Aperture wall smoothness;electrochemical machining;laser-cut electropolished stencils;metal stencils
Department/Centre:	Division of Electrical Sciences > Electronic Systems Engineering (Formerly Centre for Electronic Design & Technology)
Date Deposited:	30 Aug 2011 05:33
Last Modified:	30 Aug 2011 05:33
URI:	http://eprints.iisc.ac.in/id/eprint/40338

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