This document discusses different techniques for integrating MEMS (Micro-Electro-Mechanical Systems) into a standard BiCMOS semiconductor fabrication process. It describes a Back-End-Of-Line integration technique that uses the metallization layers of a BiCMOS process along with additional MEMS processing steps. A back-side substrate etching technique is also discussed for preventing substrate losses in passive components. Fully embedding these MEMS integration methods could allow single-chip mm-wave transceivers to be realized using cost-effective standard silicon processes operating at higher frequencies with lower losses.

1. Seminar
on
Embedded MEMS Modules for BiCMOS Process
Submitted to :
Dr. R. Nakkeeran
Associate Professor
Dept. of electronics
Pondicherry university
Submitted by :
Himanshu ranjan das
M.Tech (electronics)
Pondicherry university

2. ABSTRACT
 Different MEMS process techniques have been integrated to 0.25 μm BiCMOS
process. First developed technique is Back-End-Off-Line (BEOL) integration.
This technique was developed using standard metallization layers of BiCMOS
process with an additional MEMS process steps. An RFMEMS capacitive
switch was realized using BEOL embedded MEMS module. Back-side
substrate etch method was developed as second MEMS integration technique.
This technique is demonstrated by several high-Q passive components which
can prevent from substrate losses. Additional MEMS modules were achieved
by only adding few more lithography and etch steps. Fully embedded
integration of these MEMS process techniques to a standard BiCMOS process
will allow realizing single-chip mm-wave transceivers using cost-effective
standard SiGe process and allows designer to operate higher frequencies with
less losses.

3. What is MEMS?
 Micro-Electro-Mechanical Systems, or MEMS, is a technology that
in its most general form can be defined as miniaturized
mechanical and electro-mechanical elements (i.e., devices and
structures) that are made using the techniques of
microfabrication. The critical physical dimensions of MEMS
devices can vary from well below one micron on the lower end
of the dimensional spectrum, all the way to several millimeters.
Note: MEMS are made up of components between 1 to 100
micrometres in size (i.e. 0.001 to 0.1 mm), and MEMS devices
generally range in size from 20 micrometres (20 millionths of a metre)
to a millimetre (i.e. 0.02 to 1.0 mm).

4. What Is bicmos ?
 BiCMOS' is an evolved semiconductor technology that integrates
two formerly separate semiconductor technologies - those of
the bipolar junction transistor and the CMOS transistor - in a
single integrated circuit device.

5. Advantages of bicmos
 Bipolar junction transistors offer high speed.
 High gain, and low output resistance, which are excellent
properties for high-frequency analog amplifiers.
 whereas CMOS technology offers high input resistance and is
excellent for constructing simple, low-power logic gates.

6. Disadvantages
 BiCMOS as a fabrication process is not currently as commercially
viable for some applications, such as microprocessors, as with
exclusively BJT or CMOS fabrication. Unfortunately, many of the
advantages of CMOS fabrication, for example, do not transfer
directly to BiCMOS fabrication.
 An inherent difficulty arises from the fact that optimizing both the BJT
and MOS components of the process is impossible without adding
many extra fabrication steps and consequently increasing the
process cost

7. Why bicmos……?
 There is a growing interest in providing fully integrated solutions with the
availability of the new applications such as 60 GHz for wireless personal
area wireless network, the 77 GHz for adaptive cruise control radar and
the 94 GHz for military radar applications. As the operating frequency
of RFICs moves to mm-wave frequency range, it becomes difficult to
achieve affordable Q-factors from on-chip passive components using
conventional thin-film, planar IC processes.
 MEMS processing techniques came up as an emerging technology for
realizing high performance passive components at high frequencies.
Several different MEMS processing techniques were developed and
published.
 In fact, the results of these works seem excellent but integration
problem of these structures to high-frequency BiCMOS ICs came up
due to packaging and handling of these structures.

8. Cont…….
Several integration methods were tried to integrate
MEMS components into IC using hybrid, monolithic and
post-processing methods . Especially for mm-wave
circuits, developed integration methods are not adequate due
to the effects of parasitic components from integration
methods. Figure. 1 summarizes the basic integration methods
of MEMS to BiCMOS silicon substrates.

9. Areas of work
 Back End of Line (BEOL) Technology Integration.
 Integration of MEMS switches into a standard CMOS or BiCMOS
Back-end-of-Line (BEOL) is appearing to be the most promising
one to enable the realization of fully integrated multi-band
transceivers.
 Integrating of RF mems using bicmos process.
 packaging and handling of these structures.

10. SOFTWARE REQUIRED :
COMSOL.
COVENTOR.
MEMS+.
INTELLISUITE SOFTWARE.

11. comsol
 Comsol multiphysics is a finite element analysis
, solver and simulation software/package for
various physics and engineering
application,especially coupled phenomena
or multi physics.

13. coventor
 Coventor is a software predicting actual from virtual.
 It provides predictive 3D modelling and simulation for
advance micro and nano fabrication technologies.
 It enables to simulate ,optimize the fabrication process
and is a time consuming process

14. coventor
 Successful MEMS suppliers verify all aspects of their designs with simulations
before sending them to the fab. Successful MEMS suppliers use the
CoventorWare® design and simulation platform.

15. Mems +
 MEMS+® provides designers with a solution to this vexing
challenge. MEMS+ is a different kind of FEA, based on a
unique MEMS-specific library of high-order, parametric
finite elements.

16. conclusion
 We are convinced that in near future, there is a need for integrating MEMS
processing techniques in order to develop the concept of Microsystems for
mm-wave communications. Fully embedded integration of these MEMS
process techniques to a standard BiCMOS process will allow realizing
single-chip mm-wave transceivers using cost-effective standard SiGe
process and allows designer to operate higher frequencies with less losses.

17. REFERENCE
 Embedded MEMS Modules for BiCMOS Process ,Technische
Universitat Berlin, HFT4, Einsteinufer 25, 10587, Berlin,
Germany

18. Thank u....!