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  Mems device package and method for manufacturing the sameUSPTO Application #: 20060141652Title: Mems device package and method for manufacturing the same Abstract: A micro electromechanical system (MEMS) device package and a method of manufacturing the same are provided. The MEMS device package includes: a device substrate with a MEMS active device being formed on the top surface thereof; internal electrode pads, each of which is positioned on the opposite side of the MEMS active device and electrically connected to the MEMS active device; sealing pads positioned outside of the internal electrode pads; a closure substrate joined to the device substrate through the sealing pads, the closure substrate having via holes formed at the areas where the internal electrode pads are positioned; and external electrode pads formed on the top surface of the closure substrate in such a way that the external electrode pads are electrically connected to the internal electrode pads through the via holes. The internal electrode pads and the sealing pads are formed from an identical material such as Au and thus the device substrate and the closure substrate are bonded to each other with direct bonding such as Au—Au direct bonding via the sealing pads. (end of abstract) Agent: Sughrue Mion, PLLC - Washington, DC, US Inventors: Jong-seok Kim, Yun-kwon Park, In-sang Song, Duck-hwan Kim, Kuang-woo Nam, Seok-chul Yun USPTO Applicaton #: 20060141652 - Class: 438048000 (USPTO) Related Patent Categories: Semiconductor Device Manufacturing: Process, Making Device Or Circuit Responsive To Nonelectrical Signal The Patent Description & Claims data below is from USPTO Patent Application 20060141652. Brief Patent Description - Full Patent Description - Patent Application Claims
CROSS-REFERENCE TO RELATED APPLICATIONS [0001] This application claims priority from Korean Patent Application No. 2004-112700 filed Dec. 27, 2004 in the Korean Intellectual Property Office, the disclosure of which is incorporated herein by reference. BACKGROUND OF THE INVENTION [0002] 1. Field of the Invention [0003] Apparatuses and methods consistent with the present invention relate to a micro electromechanical system (MEMS) device package and a method for manufacturing the same. [0004] 2. Description of the Related Art [0005] MEMS is the integration of sensors, micro actuators, gyroscopes, precise machine parts, etc. using semiconductor processing technology. As a high level of precision, product uniformity, and superior productivity required for semiconductor processing are applied to MEMS, MEMS is recognized as a technology capable of improving performances of products while reducing costs. [0006] MEMS devices such as acceleration sensors, angular velocity sensors, resonant gyroscopes, or the like are packaged for the purpose of enhancing protectability and/or sensitivity thereof. As high density and miniaturization of MEMS devices have been realized due to the rapid development of technologies for manufacturing MEMS devices, it is also required for packages to be correspondingly miniaturized. For this purpose, Wafer Scale Package (WSP) application for packaging devices in a wafer state is frequently attempted. [0007] FIG. 1 is a cross-sectional view schematically showing an example of a conventional MEMS device package. As shown in the drawing, a device substrate 1 is provided with a MEMS active device 2, and a glass closure substrate 3 is joined to the device substrate 1 for protecting the MEMS active device 2. The MEMS active device 2 typically has a spring structure and a stage supported by the spring structure. [0008] In addition, internal electrode pads 5 are formed on the device substrate 1, wherein each of the internal electrode pads is positioned on the opposite side of the MEMS active device 2 and electrically connected to the MEMS active device 2. A cavity 4 is formed under the glass closure substrate 3 for providing a space for receiving the MEMS active device 2, wherein the glass closure substrate 3 and the device substrate 1 are anodic-bonded to each other. [0009] In addition, via holes 6 are formed on the opposite sides of the glass closure substrate 3, and external electrode pads 7, which are connected to the internal electrode pads 5, are formed through the via holes 6. Here, the via holes 6 are formed through a sandblasting process, and the external electrodes 7 are formed by filling a metallic material (typically Al) in the via holes 6 through a sputtering process. The external electrode pads 7 are connected to a signal line on a circuit board not shown in the figure through a wire, a bump or the like. [0010] However, a conventional MEMS device package as described above inevitably has a thick glass closure substrate 3 due to the bonding structure between the glass closure substrate 3 and a silicon-based device substrate 1 and the manufacturing process of the MEMS device package, whereby there is a limit in reducing the size of the package due to the via holes 6 in the glass substrate 3. In other words, due to a large size and a high height, such a conventional MEMS package occupies a large volume in an apparatus incorporating it, thereby causing the miniaturization of the apparatus to be hindered. [0011] Furthermore, because such a conventional MEMS package employs a closure substrate 3 formed from glass, the processes for forming the via holes 6 and the external electrode pads 7 are difficult to perform and require much time, thereby causing a decrease in yield and productivity. [0012] Such a conventional MEMS package also has a problem in that the MEMS active device 2 may be deformed or damaged due to high temperature (typically about 460.degree. C.) at the time of anodic-bonding and has basic stress due to the difference in thermal expansion coefficient between the glass closure substrate 3 and the silicon-based device substrate 1. [0013] Moreover, a problem of reliability may be presented because the connection of a circuit by means of the internal electrode pads 5 formed from a silicon material and the external electrode pads 7 formed from a metallic material produces a very high inductance in relation to RF signals of high frequency and electrical contact resistance at the contact parts, thereby causing a high loss in signal. SUMMARY OF THE INVENTION [0014] Accordingly, an illustrative, non-limiting embodiment of the present invention has been made to solve the above-mentioned problems, and an aspect of the present invention is to provide a MEMS device package, in which a closure substrate formed from a material identical to that of a device substrate is employed so as to reduce the stress caused by a difference in thermal expansion coefficient, and in which via holes for wiring of electrodes can be simply fabricated and a simple metal deposition process can be employed, so that the MEMS device package can be minimized in size, and a method of manufacturing such a MEMS device package. [0015] Another aspect of the present invention is to provide a MEMS device package, in which a device substrate and a closure substrate are bonded to each other with direct bonding, such as Au--Au direct bonding, which uses a material identical to the material forming the internal electrode pads and the sealing pads of the MEMS device package, so that the package is stable and capable of enhancing a yield, and a method of manufacturing such a MEMS device package. [0016] A still further aspect of the present invention is to provide a MEMS device package, in which a circuit connection structure is formed by contacting members formed from a same or highly conductive material so as to minimize the loss in signal, and a method of making such a MEMS device package. [0017] In order to achieve the above-mentioned aspects, there is provided a MEMS device package which includes: a device substrate with a MEMS active device being formed on the top surface thereof; internal electrode pads, each of which is positioned on the opposite side of the MEMS active device and electrically connected to the MEMS active device; sealing pads positioned outside of the internal electrode pads; a closure substrate joined to the device substrate through the sealing pads, the closure substrate having via holes formed at the areas where the internal electrode pads are positioned; and external electrode pads formed on the top surface of the closure substrate in such a way that the external electrode pads are electrically connected to the internal electrode pads through the via holes. [0018] The internal electrode pads and the sealing pads may be formed from an identical material such as Au, and the device substrate and the closure substrate may be bonded to each other with direct bonding such as Au--Au direct bonding. In addition, the external electrodes may also be formed from a material identical to the material forming the internal electrode pads and the sealing pads. [0019] According to another aspect of the present invention, there is provided a method of manufacturing a MEMS device package. The method may include following steps: a) providing a device substrate having a MEMS active device and one or more lead lines electrically connected with the active device; b) forming, on a closure substrate, internal electrode pads and sealing pads positioned outside of the internal electrode pads to a predetermined height; c) bonding the device substrate and the closure substrate to each other through the sealing pads in such a way that the MEMS active device is positioned in a space provided by the internal electrode pads and the internal electrode pads come into contact with the lead lines; d) polishing the closure substrate to a predetermined thickness; e) forming via holes at the positions where the internal electrode pads are positioned on the closure substrate; and f) forming external electrode pads which are electrically connected with the internal electrode pads through the via holes. [0020] The step b) of the above method may include sub-steps of: b1) coating a seed layer on the entire surface of the closure substrate; b2) forming a plating frame for use in forming the internal electrode pads and the sealing pads on the seed layer through a photolithography process; b3) electrically plating a material such as Au which is identical to the material forming the seed layer on the closure substrate, over the plating frame; and b4) removing the plating frame. [0021] In the above step b1), Au, as a material to form the seed layer, may be coated to a thickness of about 1,000 .ANG.. Continue reading... Full patent description for Mems device package and method for manufacturing the same Brief Patent Description - Full Patent Description - Patent Application Claims Click on the above for other options relating to this Mems device package and method for manufacturing the same patent application. ###  How KEYWORD MONITOR works... a FREE service from FreshPatents1. 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