Active solid-state devices (e.g. – transistors – solid-state diode – Responsive to non-electrical signal – Physical deformation
Reexamination Certificate
2001-01-29
2004-01-06
Jackson, Jerome (Department: 2815)
Active solid-state devices (e.g., transistors, solid-state diode
Responsive to non-electrical signal
Physical deformation
C257S642000
Reexamination Certificate
active
06674140
ABSTRACT:
BACKGROUND OF THE INVENTION
Micromachined sensors and actuators (sometimes referred to as microelectromechanical systems or MEMS and micro-opto-electro-mechanical systems or MOEMS) are made using semiconductor technologies so these microstructures have very clean surfaces. Inorganic surfaces that are extremely clean tend to stick together if they come into contact. If microstructure surfaces stick, the device becomes defective. One example of such a component is the class of inertial microsensors that measures acceleration and deceleration (e.g., an accelerometer), and an example of one of these is the sensor which determines whether an automobile is colliding and the air bag should be deployed. Another example is a gyroscope. A third example, representing non-inertial microstructures, is a micro-mirror array such as that used in optical communications and projection systems.
The airbag sensor has a sub-component which moves in response to the inertial changes that arise during rapid deceleration. The failure of this subcomponent to move during deceleration can be caused by the sticking of this micro-subcomponent to other components in its immediate environment. This concept of sticking is called “stiction”, and the concept of preventing sticking from occurring is called “anti-stiction”.
There has been some prior development of anti-stiction treatments that are applied during assembly and packaging. For example, U.S. Pat. No. 5,694,740 (hereafter referred to as '740) describes the vapor deposition of various organics, including silicones, alkoxysilanes and perfluoroethers, to the component during assembly. Although this treatment reduces stiction, it is not efficient to treat each individual component, since these electronic components are extremely small, and large numbers of these components are manufactured at one time. Fluorocarbons, also applied during assembly, have been used as anti-stiction treatments for micro-optical devices (based on the concept of a light beam being deflected by a moving mirror) in U.S. Pat. No. 5,936,758.
Anti-stiction treatments normally “passivate” the surface and are called passivants. That is, they alter surfaces to make them less interactive with their surroundings.
BRIEF SUMMARY OF THE INVENTION
This invention discloses a process for forming durable anti-stiction surfaces on micromachined structures while they are still in wafer form (i.e., before they are separated into discrete devices for assembly into packages). This process involves the vapor deposition of a material to create a low stiction surface. It also discloses chemicals which are effective in imparting an anti-stiction property to the chip. These include phenyl alkoxysilanes, polyphenylsiloxanes, silanol terminated phenylsiloxanes and similar materials.
REFERENCES:
patent: 4781942 (1988-11-01), Leyden et al.
patent: 5061049 (1991-10-01), Hornbeck
patent: 5130265 (1992-07-01), Battilotti et al.
patent: 5331454 (1994-07-01), Hornbeck
patent: 5429708 (1995-07-01), Linford et al.
patent: 5578863 (1996-11-01), De Poorter
patent: 5694740 (1997-12-01), Martin et al.
patent: 5766367 (1998-06-01), Smith et al.
patent: 5801309 (1998-09-01), Carr et al.
patent: 5822170 (1998-10-01), Cabuz et al.
patent: 5904952 (1999-05-01), Lopata et al.
patent: 5936758 (1999-08-01), Fisher et al.
patent: 5950101 (1999-09-01), Yano et al.
patent: 6063714 (2000-05-01), Smith et al.
patent: 6287430 (2001-09-01), Matsumoto et al.
patent: 6335224 (2002-01-01), Peterson et al.
Parylene Coatings, by Beach et al., pp. 789-801 inElectronics Materials Handbook: Vol. 1, Packaging, Minges et al, Eds, ASM International (1989).
Oct. 4, 2000—Slide presentationsby J. Martin toAmerican Vacuum Society Meeting, Boston, MA [abstract also included]. Oct. 9, 2000—Slide presentationby J. Martin toWorcester Polytechnic Institute, Worcester, MA [abstract included].
U.S. pat. app. Ser. No. 09/109,434 (filed Jul. 2, 1998).
Mar. 14, 2000—Slide presentationby J. Martin toNational Institute of Standards and Technology, Gaithersburg. MD.
Handbook of Electronic Package Design, Edited by Michael Pecht,CALCE Center for Electronic Packaging, University of Maryland at College Park, College Park, Maryland, Marcel Dekker, Inc., copyright 1991, pp. 21-23 and pp. 767-772.
Analog Devices Inc.
Jackson Jerome
Weingarten Schurgin, Gagnebin & Lebovici LLP
LandOfFree
Process for wafer level treatment to reduce stiction and... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Process for wafer level treatment to reduce stiction and..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Process for wafer level treatment to reduce stiction and... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3232580