MICROELECTROMECHANICAL SYSTEM
A micro electromechanical system and a fabrication method thereof, which has trenches formed on a substrate to prevent circuits from interfering each other, and to prevent over-etching of the substrate when releasing a microstructure.
Latest MEMSMART SEMICONDUCTOR CORP. Patents:
This application is a Divisional patent application of co-pending application Ser. No. 11/845,780, filed on 27 Aug. 2007. The entire disclosure of the prior application, Ser. No. 11/845,780, from which an oath or declaration is supplied, is considered a part of the disclosure of the accompanying Divisional application and is hereby incorporated by reference.
BACKGROUND1. Technical Field
The present invention relates to a microelectromechanical system (MEMS). More particularly, the present invention relates to a structure of a MEMS.
2. Description of Related Art
A microelectromechanical system (MEMS) is a combination of surface and bulk micromachitring technologies, and has been widely applied in mechanical filters, accelerometers, gyroscopes, optic modulators, and radio frequency (RF) passive devices. Generally, a MEMS comprises circuits and microstructures. U.S. Pat. No. 5,717,631 proposed a MEMS structure and process of making the same, which had the disadvantage of the generation of an undercut on a substrate under circuits or other structures adjacent to the microstructure during the release of the microstructure, thus the processing parameters must be precisely controlled in order to prevent over-etching from occurring, and protect the substrate under circuits or other structures adjacent to the microstructure from being damaged due to excessive undercut. In addition, noises generated from different circuits would be transmitted via the substrate and lead to interference between the circuits. Conventionally, such interference is prevented by using guard rings, or by allocating circuits that are prone to generating noises away from other circuits. However, the guard rings block noises
SUMMARYAn object of the present invention is to provide a MEMS with low interference, and process of making the same.
Another object of the present invention is to provide a MEMS and process of making the same that may prevent substrates from over-etching.
A MEMS according to the present invention comprises a microstructure, a circuit, and a trench located therebetween for separating the microstructure and the circuit, so as to protect performance of the circuit from deteriorating due to over-etching during the release of the microstructure.
A MEMS according to the present invention comprises a structural region having a microstructure, a circuitry region having two circuits, and a trench located between the two circuits for separating the two circuits, so as to prevent the circuits from interfering each other.
A process of making a MEMS according to the present invention comprises a pre-process to form a microstructure and a circuit on a substrate, a metal layer on a top surface of the microstructure and the circuit, and an insulation layer covering over the microstructure and the circuit, a first etching process for removing a portion of the insulation layer not covered by the metal layer, a second etching process for removing a portion of the substrate not covered by the metal layer, forming a mask on the substrate for covering over the circuit and exposing the microstructure, and a third etching process for releasing the microstructure from the substrate.
A method for fabricating a MEMS according to the present invention comprises a pre-process to form a microstructure and a circuit on a substrate, and an insulation layer covering over the microstructure and the circuit, forming a first mask on the insulation layer for covering the microstructure and the circuit, performing a first etching process for removing parts of the insulation layer not covered by the first mask, performing a second etching process for removing parts of the substrate not covered by the first mask, forming a second mask on the substrate for covering the circuit and exposing the microstructure, and performing a third etching process for releasing the microstructure.
In the present invention, the interference between the circuits may be lowered via the trenches located between the circuits, so that interference within the MEMS may be minimized. In addition, the over-etching of the substrate may be prevented via the trenches located between the microstructures and the circuits, so as to protect the properties of the circuits from deteriorating and reduce the interference between the circuits and the microstructures. Because the trenches are generated during the release of the microstructures, the aim of releasing microstructures, lowering interference, and preventing over-etching may be achieved simultaneously without increasing the complexity and costs of the manufacturing process thereof.
The invention can be more fully understood by reading the following detailed description of the embodiment, with reference made to the accompanying drawings as follows:
The present invention will be clearer from the following description when viewed together with the accompanying drawings, which show, for purpose of illustrations only, the preferred embodiment ill accordance with the present invention.
In a different embodiment, the grooves 214, 216, and 218 may be formed via the steps shown in
The structure of the MEMS 300 and fabrication method thereof is illustrated in a cross-section cut across the direction of B-B′ in
In different embodiments, the trench may be located between the microstructure and the circuit, or between different circuits, or any regions that needs to be isolated from other regions, and corresponding structures may be generated via the pre-process. The required trenches may be formed via the steps shown in
While the present invention has been described in conjunction with preferred embodiments thereof, it is evident that many alternatives, modifications and variations will be apparent to those skilled in the art. Accordingly, it is intended to embrace all such alternatives, modifications and variations that fall within the spirit and scope thereof as set forth in the appended claims.
Claims
1. A microelectromechanical system, comprising:
- a microstructure;
- a circuit; and
- a trench located between the microstructure and the circuit for separating the microstructure and the circuit to prevent over-etching from occurring when releasing the microstructure and protect properties of the circuit from deteriorating, as well as preventing the microstructure and the circuit from interfering each other;
- wherein the trench is generated during the process of releasing the microstructure.
2. A microelectromechanical system, comprising:
- a microstructure;
- a circuitry region having two circuits side by side; and
- a trench located between the two circuits for separating the two circuits to prevent the two circuits from interfering each other;
- wherein the trench is generated during the process of releasing the microstructure.
Type: Application
Filed: Jan 5, 2010
Publication Date: May 6, 2010
Applicant: MEMSMART SEMICONDUCTOR CORP. (Hsinchu)
Inventors: Li-Ken YEH (Hsinchu), I-Hsiang CHIU (Hsinchu)
Application Number: 12/652,736
International Classification: H01L 29/00 (20060101);