This application claims the benefit of Korean Patent Application No. 10-2008-0027837 filed on Mar. 26, 2008, which is hereby incorporated by reference.
1. Field of the Invention
The present invention relates to a packaging method of a micro electro mechanical system (MEMS) device and a package thereof.
2. Description of the Related Art
In general, MEMS devices have been applied in various fields such as optical communication, RF devices, and storage media using surface micromachining technology. Further, MEMS devices have been used in main parts such as a sensor of an information device or a printer head. Accordingly, there is a need for packaging protecting MEMS devices from physical or chemical environments so the MEMS devices have stability and reliability.
Packaging methods of the MEMS devices may be mainly classified into adhesion type and in-situ type.
Referring to
Next, referring to
Referring to
Thereafter, referring to
In the in-situ type packaging method, in order to remove the sacrificial layer 240, the etching holes 230 are formed in the vicinity of edges of the MEMS device 210. In a case where the sacrificial layer 220 is removed using the etching holes 230, it takes a long time. Moreover, the MEMS device 210 can be physically and chemically damaged during removal thereof.
The present invention has been made in view of the above problems, and it is an object of the present invention to provide a packaging method that may minimize physical or chemical damage of MEMS devices and reduce a time of a packaging process.
It is another object of the present invention to provide a package of MEMS devices manufactured by the packaging method according thereto.
In accordance with an exemplary embodiment of the present invention, there is provided a packaging method of a micro electro mechanical system (MEMS) device comprising: sequentially forming a sacrificial layer, a support layer, and a block copolymer layer on a substrate on which the micro electro mechanical system device is formed; (b) self-assembling the block copolymer layer formed on the support layer; (c) selectively etching a part of the self-assembled block copolymer layer to form a plurality of nano-pores; (d) forming a plurality of etching holes in the support layer corresponding to the plurality of nano-pores using the block copolymer layer in which the plurality of nano-pores are formed as a mask; (e) removing the sacrificial layer using the etching holes formed in the support layer; and (f) forming a shielding layer on the support layer.
Preferably, the packaging method includes removing the block copolymer layer in which the plurality of nano-pores are formed after step (d).
Preferably, the sacrificial layer formed to comprise material consisting of metal or polymer.
Preferably, the support layer is formed to comprise at least one of a silicon oxide, a silicon nitride, and a silicon carbide.
Preferably, step (b) comprises: spin-coating the block copolymer layer formed on the support layer; and heating treat the spin-coated block copolymer layer to self-assemble the block copolymer layer so that a plurality of assembled monomers with a cylindrical structure are formed.
Preferably, step (c) comprises: patterning a photo-resist to expose a partial region of the block copolymer layer; irradiating light on the exposed block copolymer layer using the photo-resist as a mask; and
removing the plurality of assembled monomers with the cylindrical structure from the block copolymer layer to the light is irradiated.
Preferably, the shielding layer is formed to comprise at least one of a silicon oxide, a silicon nitride, and a silicon carbide.
Preferably, the shielding layer is formed to comprise at least one of benzocyclobutene (BCB) and polyimide.
In accordance with another aspect of the present invention, there is provided a package of a micro electro mechanical system (MEMS) device comprising: a micro electro mechanical system device formed on a substrate; a support layer being spaced apart from the micro electro mechanical system device formed on the substrate to enclose the micro electro mechanical system device wherein a plurality of etching holes are formed in an upper portion of the support layer; and a shielding layer formed to enclose the support layer.
Preferably, the support layer comprises at least one of a silicon oxide, a silicon nitride, and a silicon carbide.
More preferably, the shielding layer comprises at least one of a silicon oxide, a silicon nitride, and a silicon carbide.
Most preferably, the shielding layer comprises at least one of benzocyclobutene (BCB) and polyimide.
In the present invention, a removal time of a sacrificial layer may be reduced and physical or chemical damage of MEMS devices may be minimized by forming an etching hole for removing the sacrificial layer in an upper part of the MEMS devices using a self assembled nano-structure of a block copolymer layer to remove the sacrificial layer.
The objects, features and advantages of the present invention will be more apparent from the following detailed description in conjunction with the accompanying drawings, in which:
Hereinafter, a packaging method of a MEMS device in accordance with a preferred embodiment of the present invention will be described in detail referring to the accompanying drawings. The same reference numerals are used throughout the drawings to refer to the same or like parts. Detailed descriptions of well-known functions and structures incorporated herein may be omitted to avoid obscuring the subject matter of the present invention.
A packaging method of a MEMS switch device being an example of the MEMS device will be explained in an embodiment of the present invention.
In the method for manufacturing an MEMS switch device, referring to
Next, referring to
Subsequently, referring to
Next, referring to
A packaging method of a MEMS switch device in accordance with an embodiment of the present invention will be explained in detail by reference to the accompanying drawings hereinafter.
Step (a)
In step (a), referring to
The support layer 330 is formed on the sacrificial layer 321. The support layer 330 may be formed comprising at least one of silicon oxide, a silicon oxide, and a silicon carbide, which have excellent mechanical strength.
Subsequently, referring to
Step (b)
In step (b), the block copolymer 340 is spin-coated and undergoes a heat treatment at a temperature equal to or higher than 150° C. The heat treatment is performed at a temperature ranging from a glass transition point Tg of the block copolymer 340 to a melting point Tm thereof. A self-assembled structure can be classified into a sphere type, a cylinder type, a cut spiral type, and a layer type according to a mixing amount, molecular mass, surface energy, or bonding power of assembled monomers. Specific structures of an assembled monomer may be formed through a variety of factors such as a direction of the substrate 300, externally applied energy, and surface modification. In the embodiment of the present invention, the block copolymer layer 340 undergoes a heat treatment at a temperature ranging from about 200° C. to 250° C. Accordingly, referring to
Meanwhile, a diameter of the assembled monomers 345 and a spacing between the assembled monomers 345 can be adjusted according to molecular mass and a mixing amount of assembled monomers used in the block copolymer layer 340.
Step (c)
In step (c), referring to
Step (d)
In step (d), a support layer 330 is selectively etched using the block copolymer layer 340 on which the plurality of nano-pores 343 are formed. Accordingly, referring to
Step (e)
In step (e), referring to
Step (f)
In step (f), referring to
In the meantime, for adjusted atmosphere packaging, the support layer 330 may be coated with polymer materials such as benzocyclobutene (BCB) and polyimide under a desired atmosphere, and the resulting object undergoes a heat treatment to form the shielding layer 350. When the support layer 330 is coated with polymer materials with high viscosity, the polymer materials can penetrate between the etching holes 333 to more safely protect the MEMS switch device 310.
The details of a package of the MEMS switch device manufactured according to an embodiment of a packaging method of a MEMS device of the present invention is seen with reference to the accompanying drawings.
The package of a MEMS switch device in accordance with an embodiment of the present invention includes a MEMS switch device 310, a support layer 330, and a shielding layer 350.
A first insulation layer 301 is formed on a substrate 300. In this case, the MEMS switch device 310 is formed on the first insulation layer 301. The MEMS switch device 310 comprises a plurality of metal electrode layers 302, a MEMS switch beam 305 performing a switching operation through the metal electrode layers 302, and a second insulation layer 303 formed on the metal electrode layer to be spaced apart from the MEMS switch beam 305.
The support layer 330 is formed to enclose the MEMS switch device 310 formed on the substrate 300. The support layer 330 is spaced apart from the MEMS switch device 310 by a predetermined distance so that a fluidized space of the MEMS switch beam 305 may be secured. A plurality of nano-sized etching holes 333 are formed in an upper portion of the support layer 330. The support layer 330 comprises at least one of a silicon oxide, a silicon nitride, and a silicon carbide with excellent mechanical strength.
The shielding layer 350 is formed to enclose the support layer 330. The shielding layer 350 functions to seal an inside of the support layer 330 in a vacuum or gas state. The shielding layer 350 comprises at least one of a silicon oxide, a silicon nitride, and a silicon carbide. Since the silicon oxide, the silicon nitride, and the silicon carbide have excellent mechanical strength, it can well resist pressure due to an atmosphere difference between an inside to which the MEMS switch device 310 is packaged and an outside thereof. In a case of an adjusted atmosphere package,
the shielding layer 350 can be formed to include at least one of benzocyclobutene (BCB) and polyimide.
Although embodiments in accordance with the present invention have been described in detail hereinabove, it should be understood that many variations and modifications of the basic inventive concept herein described, which may appear to those skilled in the art, will still fall within the spirit and scope of the exemplary embodiments of the present invention as defined in the appended claims.
Number | Date | Country | Kind |
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10-2008-0027837 | Mar 2008 | KR | national |