Three - University of Arkansas Physics Department

IMAPS - EUROPE PRAGUE 2000
-
Prague. Czech Republic, June - 18-20 2CG:
50th Electronic Components and Technology Conference, p 1278-84,2000
Mixed-Signal and Mixed-Technology Systems:
Multi-Domain b4odulcs (MDMs) or Ncxt Generation MCMs
Ajay P. ~alshe].', Alan Mantooth', Simon Ang'. Fred Barlow', Aicha Elshabinii*. K. OlejniCzak1,
Greg Salamo3, Len Schaper', Rick LTLrich'.', and William Brown'.
High Density Electronics Center (HiDEC)
I-Depariment pf Electrical Engineering; 2-gepartment of Mechanical Engmeenng;
3-Departmeat of Physics; 4Dcpariment af Chemical Enginming,
University of Arkansas, Fayetteuille, Arkansas 72701
'Contact Phone: 501-575-300513009 Fax: 501-575-7967 e-mail: aicha@engr.uark.edu
ABSTRACT
Despite the increasing functionality of electronic systems provided by rapid progress in digital
integrated circuits (ICs), the external world is analog. Thus, vhally all electronic systems must be
wmidered as mixed-signal, not only in the traditional analogldigitd sense, but also in the bmader context
of interfaces between digital circuits and RF, optical, physical, chemical, and biological system elements.
Mixed-signal deviccs and systems are becoming increasingly impartant in the elechunics industry. With
integrated circuits moving from tens of millions to hundreds of millions of transistors on a chip, entire
systems are being moved onto a single chip. There is prcssurc to place both the analog and digital
components of a product onto the same chip, creating a mixedsignal chip, or in the same MCM part.
This is especially true in wireless telecommunications. Another force creating mixed-signal devices is the
bcrensing use of digital processing of analog signals. A digital signal-processing device requires analag
fiiters, samplers, A/D C~nvertcrs, among other functions, at the front and back end of the digital
processing circuitry. Yet another factor 1s the increasing use of analog circuitry within digital circuitry.
A DRAM chip, for example, is very much a mixed signal device. Its sense amplifiers. and the data
storage cells themselves, are very much analog circuifq; while the rest of the circuit is bas~cally digital.
hblems with signal distribution on digital chips at deep submicron geomeiries lead to the use of analog
circuitry for increased speed of signal propagdtion (primarily amplifiers and comparators). Noise and
signal degradation problems that result from line width shrinkage are also best analyzed by analog
simulation. A MEMS (Micro-Elecfr'o-Mechanical) chip is another good example of a mixed-technology
system. A MEMS chip may contam both electronic and micro-mechanical components. A MEMS
device used for biomedical or biotechnology purposes may contain micro-fluidic components, chemical
components, or sensors. A nnxed-technology device may also contain both electronic and optical
components. Simulation problems similar to those in mixed 'analog/digitalS systems are encountered in
these kinds of systems.
The 1997 Silicon Industries Association (SIA) roadmap describes the progress expected in
integrated circuit technology over the next 10 years. The minimum design rule will go from 180 nm to 70
• nm, DRAM density m production bom 256 Mb to IG Gb, usable logic transistors on an ASIC from 14 M
to 64 M, and maximum on-chip global clock frequency from 12 GHz to 2.5 GHz. In short, the 'brains"
of electronic systems. the digital logic and memory. will continue to shnnk dramatically in size, weight,
and cost, while continuing to increase in performance. Electronic systems, however, are not on the same
pmgress curve.
Due to all the packaging, signal conditiomng, and analog hardware that accompany digital
electronics, the functional density berformance per volume) at the system level has increased far more
slowly than ar the chip level. Even thoqgh system advances have been dramatic, it is clear that new
technologies are required to allow systems to achieve. the same progress as chips. Thus, a great deal of
development is bemg done on chtp scale packages (CSPs) to reduce the size of the chip package almost to
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IMAPS - EUROPE PRAGUE 2000 Prague, Czech Republic, June 18-20,2000
the size of the chip itself. Passive components (resistors, capacitors, and inductors), which can be
integrated into the Printing Wiring Board (PWB) or other interconnect subsnte, are king developed.
High frequency PC-DC converters for supplying chip opcrattng voltages are far smalker thsn their lower
frequency counterparts. Improved techniques of heat removal, such as heat pipes, are allowing high
power chips to be packed mwe closely and in wnfmed spaces, such as laptop. Yet progress is still not as
bst as for semiwnductors.
There are three critical issues facing mixed-signal, mked-techn~logy system implementation in
the coming decade, where systems of importance include communication, data acquisition, medical,
entertainment, military, industrial control, and many others. They arc (1) intdlces - seaxnless integratisn
of interfaces with core digital electronics; (2) design, simulation, and testing tools - a beaer design,
simulation, and test approach is needed; and (3) functional density (i.e., performance per unit volume) -
integral passive components and improved packaging techniques, including adequate thermal
managcmmt. A goal of two ordm of magnitude improvement, within ten years, in these three broad
areas that now limit progress in realizing Fully Integrated Electronic Systerns (TIES), s e reasonable. ~
Thus, a critical need exists for the inteption, through advanced etectronic packaging
technologies, of multifunctional, mixed-signal, and mixed-technology electronic systems. Unlike
conventional electronic packaging, which primarily provides for the intcrcom~tion of electrical signaks,
the next generation of electronic packaging will most likely have to deal with optical (i.e., integrated
optics), mechanical (i.e.. MEMs), chemlcsl (is., sensors), magnetic (i.e., actuators), neural (i.e.. neuronactivated
impulses), etc. signals. Although smaller (denser), faster (in speed), and cheapcr are the
wnventionel constrains on these systems as well.
System on a chip, or system on a module, or system in a package The choice for a given
electronic system will be wnkolled primarily by constraints on the system and the availability of
solutions to the three critical issues noted prev~ously. Each of these k c system packaging approaches
have their own set of physical, functional and environmental constraints, in addition to the "smallerfaster-cheaper"
boundary conditions and, = the number of constraints increases, t+sdegrees of freedom,
i.e., the means of packaging and integrating these sub-systems into a harmonious working system,
decreases. This paper will address the challenges and technologies required, within the next ten years, to
design, fabricate, and test FIES in the form of multidomam modules (MDMs), tbe next generation of
rnultichip modulcs (MCMs). and other system packaging technologies which have not, as yet, been
envisioned.
Presenter and contact infomation: Phone (501) 575-3005
Abstract to be submitted to IMPAS'2000, Europe 482 Abstract to bc rubmincd to IMPAS'2000. Europe
483