Embedded passives 'hot topic' at APEX 
News Analysis by Julia Goldstein, Advanced Packaging contributing editor 
(March 02, 2004) Anaheim, Calif.?The mood at this year's APEX/IPC show was 
positive. One area of increased interest was embedded passives. Embedded 
passive devices have existed for years, but are now getting a chance at 
volume production because of the high-density requirements for PCBs and 
substrates. 
When asked "What's new?," Mentor Graphics mentioned the addition of 
embedded passive capability to their design tools. 
Meetings of the Embedded Passive Devices Materials Task Group fo IPC were 
well attended, with active discussion of the standards documents under 
development. Chair David McGregor, of DuPont, said that IPC standards on 
materials for embedded passive devices, in development for several years, 
are expected to go to balloting this year. Separate documents will be 
released for capacitor and resistor materials, covering a wide variety of 
materials and fabrication processes. 
Several companies displayed embedded capacitor materials, including 3M and 
Oak-Mitsui. 3M reported a lot of inquiries for their high-value barium 
titanate capacitors. Oak-Mitsui produces a family of polymer film-based 
capacitors with very thin dielectrics, 24 microns down to 8 microns, and 
capacitance values ranging from 1.0 to 3.1 nF per sq. inch. 
Demand currently is focused on thicker dielectrics in this range, but 
Oak-Mitsui predicts their higher-value product with a 12-micron-thick 
dielectric will take off in the future?when the market demands 
higher-value capacitors. DuPont displayed both ceramic capacitors and 
resistors. 
Gould recently began volume production of its embedded thin film 
resistors, and also introduced TRC+ resistors designedfor improved bonding 
on phenolic resin systems. Sheet resistance values range from 25 to 250 
Ohms/sq., with tolerances of +/- 10 percent after fabrication, and a +/- 1 
percent after laser trimming. ESI's Kim Fjeldsted noted that embedded 
passives are just starting to require tolerances that need laser trimming. 
ESI's laser trimming equipment is compatible with a variety of thin and 
thick film resistor technologies, and the company predicts an exciting 
year ahead. 
-By Julia Goldstein, contributing editor