Removal of hybrid microcircuit beam--lead devices for postmortem tests

The Scanning Electron Microscope (SEM) is an important tool in Thick Film Hybrid Microcircuits Manufacturing because of its large depth of focus and three dimensional capability. This paper discusses some of the important areas in which the SEM is used to monitor process control and component failure modes during the various stages of manufacture of a typical hybrid microcircuit.Figure 1 shows a thick film hybrid microcircuit used in a Motorola Paging Receiver. The circuit consists of thick film resistors and conductors screened and fired on a ceramic (aluminum oxide) substrate. Two integrated circuit dice are bonded to the conductors by means of conductive epoxy and electrical connections from each integrated circuit to the substrate are made by ultrasonically bonding 1 mil aluminum wires from the die pads to appropriate conductor pads on the substrate. In addition to the integrated circuits and the resistors, the circuit includes seven chip capacitors soldered onto the substrate. Some of the important considerations involved in the selection and reliability aspects of the hybrid circuit components are: (a) the quality of the substrate; (b) the surface structure of the thick film conductors; (c) the metallization characteristics of the integrated circuit; and (d) the quality of the wire bond interconnections.

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Test Method of Current Leakage for Dielectric Paste

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.220-223.1573 ◽

2012 ◽

Vol 220-223 ◽

pp. 1573-1576

Author(s):

Zhi Hong Hou

Keyword(s):

Glass Substrate ◽

Dielectric Layer ◽

Screen Printing ◽

Test Method ◽

Conducting Layer ◽

Current Leakage ◽

Test Circuit ◽

Conductive Line ◽

Hybrid Microcircuit ◽

Sintering Processes

A test method of current leakage for dielectric paste was proposed by simulating the application processes of dielectric paste for manufacturing the dielectric layer in the multilayer thick film hybrid microcircuit. That is, by screen printing and sintering processes, the sliver conducting layer was fabricated on the surface of glass substrate, and then dielectric layer, finally the glass substrate sample with conducting layer and dielectric layer was dipped in 5 Wt% NaCl aqueous solution. The conductive line was soldered on the silver conducting layer to form the test circuit, and powered with 5 volts direct power, the current in the test circuit was taken as the current leakage of the dielectric paste. The method may be used to evaluate the current leakage of dielectric paste.

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