Mirror process using tungsten passivation layer for preventing metal-spiking induced mirror bridging and improving mirror curvature

a technology of tungsten passivation layer and mirror, which is applied in the field of mirror technology of microelectromechanical system (mems) and can solve the problems of undesirable mirror curvature or mirror coupling problem, sidewall spiking problem still occurring, and mirror bridging phenomenon, so as to prevent metal spiking induced mirror bridging and improve mirror curvatur

Inactive Publication Date: 2006-02-23
TAIWAN SEMICON MFG CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Benefits of technology

[0006] It is an object of the present invention to provide a mirror process using a tungsten passivation layer to prevent metal-spiking induced mirror bridging and improve mirror curvature.

Problems solved by technology

Unfortunately, a sidewall-spiking problem still occurs because aluminum diffuses into subsequent interfacing silicon through the patterned sidewalls of the aluminum mirror film.
This accompanying sidewall-spiking problem also results in a mirror bridging phenomenon.
The oxide spacer process, however, is difficult to control an etching termination, which may lead to an undesirable mirror curvature or a mirror-coupling problem.
For example, in an under-etching case, oxide residues are produced to couple the discrete mirror structures together, resulting in a mirror malfunction.

Method used

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Embodiment Construction

[0012] The present invention provides a mirror process using a tungsten passivation layer to prevent metal-spiking induced mirror bridging and improve mirror curvature. Particularly, the present invention uses a blanket deposition for the tungsten passivation layer to overcome the aforementioned problems of the prior art through the use of an anisotropic dry etch step in an oxide spacer process. The inventive mirror process has wide applicability to various light-reflecting mirror systems, since the stability of mirror curvature is essential for reliable operation of most of the MEMS-based optical devices. Examples of such devices include light switches, optical modulators, optical attenuators, signal attenuators, and the like. A wide variety of MEMS mirror devices can be made in accordance with the methods and materials of the present invention.

[0013] Hereinafter, reference will now be made in detail to the present preferred embodiments of the invention, examples of which are illu...

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Abstract

A mirror process uses a tungsten passivation layer to prevent metal-spiking induced mirror bridging and improve mirror curvature. A mirror structure is patterned on a first sacrificial layer overlying a substrate. A tungsten passivation layer is then blanket deposited to cover the top and sidewalls of the mirror structure. A second sacrificial layer is formed overlying the tungsten passivation layer. A releasing process with an etchant including XeF2 is performed to remove the second sacrificial layer, the tungsten passivation layer and the first sacrificial layer simultaneously.

Description

FIELD OF THE INVENTION [0001] The present invention relates to microelectromechanical system (MEMS) mirror technologies, and particularly to a mirror process using a tungsten passivation layer for preventing spiking-induced mirror bridging and improving mirror curvature. BACKGROUND OF THE INVENTION [0002] Microelectromechanical system (MEMS) devices are of increasing commercial interest and importance for use in a variety of applications, such as sensors, accelerometers, electrical switches, optical switches, microlenses, capacitors, inductors, and micromirrors for direct view and projection displays. An emerging projection display technology called Digital Light Processing (DLP) accepts digital video and transmits to the eye a burst of digital light pulses that the eye interprets as a color analog image. DLP is based on a MEMS device known as the Digital Micromirror Device (DMD). The DMD is a fast reflective digital light switch, which combines with image processing, memory, a ligh...

Claims

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Application Information

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Patent Type & Authority Applications(United States)
IPC IPC(8): C23F1/00B44C1/22
CPCB81B2201/04G02B26/0833C23F4/00
Inventor WANG, WEI-YACHENG, CHUNG-YUANWU, TZU-YANGHUNG, KEVENCHEN, FEI-YUH
Owner TAIWAN SEMICON MFG CO LTD
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