1. Field of the Invention
The present invention relates to a manufacture method for manufacturing a micro-electromechanical system (hereinafter also referred to as “MEMS”) with a low cost and a high efficiency, a die used for the method, manufacture apparatuses used for the method such as a die or a film, and a micromechanical system manufactured by them.
2. Description of the Related Art
Conventionally, the MEMS has been manufactured using a semiconductor manufacturing process such as a film formation apparatus, an exposure apparatus, or an etching apparatus. Atypical manufacturing method of a MEMS device has been carried out, as shown in the following Patent Publications, Japanese Patent Laid-Open No. 2006-332391 and Japanese Patent Publication No. 3588633, by using a semiconductor manufacturing tool to subject a top face or a back face of a wafer (e.g., silicone or silica) to a lithography process to form a pattern of an organic matter or an inorganic matter. Then, the pattern formed on the top face or the back face is etched as a protective layer to thereby form a structure. After these processes for forming the structure are performed a plurality of times, then a process is performed to form an electrode layer functioning as an electric contact or an electrostatic actuator, a piezoelectric layer, a micro coil for example formed by a high-dielectric material layer consisting of a magnetic layer, a thermal deformation layer, or a light-emitting element layer. Then, the MEMS as described above can be combined with the surface of a film of synthetic resin for example to thereby realize a flexible sheet having various functions.
In order to reduce the manufacturing cost, an approach has been employed to use a wafer having an increased diameter so as to maximize the number of MEMS devices that can be manufactured from one wafer. However, the conventional MEMS manufacturing processes require, as described above, many manufacturing processes and manufacturing apparatuses. In particular, the film formation process and the etching process, which must be performed in vacuum atmosphere, causes a very high process cost, thus significantly hindering the manufacturing cost of the MEMS device from being reduced.
In view of the above, it is an objective of the present invention to provide a large amount of accurate MEMSs by using, without requiring a vacuum process or a lithography process, a die in which a minute structure is engraved with a less formation process. For example, the objective is to realize the manufacture of an optical MEMS integrated with a lens for example, an energy generation MEMS, or an MEMS used for an acceleration sensor or an inkjet nozzle with a dramatically-reduced manufacturing cost when compared with the conventional manufacturing method.
In order to achieve this objective, the method for manufacturing a micro-electromechanical system according to a first aspect of the present invention, including:
The resin can be ultraviolet cure resin, thermoset resin, or thermoplastic resin.
The die used for the micro-electromechanical system manufacture method includes:
This die may be configured so that the first convex section and the second convex section have the outer edge and the inner edge having a blade-like shape or the third concave section may have a zigzag-like shape or a plurality of stripes.
Alternatively, a die aggregation may be configured by arranging these dies in lengthwise and crosswise directions. In such case, the second convex section may be adjusted in height so as to form a thin resin layer, and the respective MEMSs may be connected by the thin resin layer and can be ejected from the die aggregation.
The film used for the above method includes a pattern-coating on the functional layer and the releasing layer coated by a screen printing, a relief printing, or a gravure printing.
This film may be configured by being provided as a film obtained by pattern-coating the functional layer via an intermediate layer to the film body or by being provided as a film obtained by etching a semiconductor substrate by the functional layer. Alternatively, a film may be provided by pattern-coating the releasing layer and the adhesive layer onto the film body by a screen printing, a relief printing, or a gravure printing to adhere the functional layer via the adhesive layer to the releasing layer.
The releasing layer may be formed of not only water-repellent resin (e.g., silicone resin) but also an organic film (e.g., resist, acrylic resin, polyester resin) dissolved in solvent (e.g., water, ethanol isopro alcohol, acetone, toluene, ethyl acetate, hexane, methyl chloride ketone) so that the film can be peeled from the die by immersing the entire film in solvent.
The micro-electromechanical system (MEMS) manufactured by the above method includes the functional layer retained by the resin filled in the functional layer retention part. The resin filled in the functional layer retention part is integrally connected to the resin part of the frame supporting the functional layer retention part. In such case, a connecting section between the functional layer retention part and the frame may be formed in an electrode layer of the functional layer. Also, the connecting section of the frame may cause the functional layer retention part to elastically deform at a predetermined stroke to the frame.
According to the method for manufacturing a micro-electromechanical system of the present invention, the vacuum process and many manufacturing processes can be eliminated, thus significantly reducing the MEMS manufacturing cost. Furthermore, in the case of the conventional MEMS manufacturing process using the semiconductor process, the manufacture of a device including the fusion of an optical lens and the MEMS requires many processes. This has caused a disadvantage in which the manufacture of a lens using a semiconductor process finds it very difficult to manufacture an aspheric lens for example.
When the method of the present invention as well as the die and the film are used, by suing a general resin molding using synthetic resin (e.g., a compressive molding, an injection molding, a transfer molding), versatile MEMSs (e.g., an optical MEMS obtained by integrating an optical plane with a MEMS device) can be simultaneously formed only by a molding process.
Therefore, a MEMS device can be provided in front of the illumination such as LED that could not be conventionally used due to a manufacturing cost for example. Thus, the combination of the LED as a point light source with the MEMS mirror can be used for various lighting machineries such as illumination and an automobile headlight for example.
Furthermore, a MEMS device also can be combined with a motion sensor to thereby realize energy-saving lighting by focusing the lighting only on a part generated from a heat source for example. Furthermore, the invention also can be used for a known MEMS device (e.g., an existing power generation MEMS or an acceleration sensor), thus similarly achieving the drastic reduction of the manufacturing cost.
Further features of the present invention will become apparent from the following description of exemplary embodiments (with reference to the attached drawings).
Hereinafter, an embodiment of the present invention will be described with reference to the drawings.
In the present embodiment, a case will be described in which a MEMS structure is configured so that a resin frame includes therein a supported functional layer composed of an electrode layer, a piezoelectric layer, or a high-dielectric material layer for example and a space is provided. The space allows, during a voltage application, the functional layer supported by the resin frame to move.
This MEMS element is configured so that the electrode layer at both left and right ends are casted into the interior of the resin part supporting the functional layer and the remaining resin at the periphery of the piezoelectric layers is removed to thereby achieve the operation of the piezoelectric element.
(1) Transfer of a Film and a Functional Layer
As shown in
In the present embodiment, the functional layer 4 includes layers (e.g., an electrode layer 4-1, a piezoelectric layer, and a high-dielectric material layer) and is formed under the releasing layer 3 via an intermediate layer (not shown).
The releasing layer 3 is composed of an inner small substantially-square part 3-2 that corresponds to the piezoelectric layer or the high-dielectric material layer for example in the functional layer 4 and an outer substantially-square frame section 3-3 corresponding to a resin frame. The inner small substantially-square part 3-2 and the substantially-square frame section 3-3 form a connecting section in the functional layer 4 that connects the electrode layer 4-1 and the corresponding part opposed thereto. Specifically, in the embodiment, the releasing layer 3 includes, except for the upper and lower U-shaped parts, a part corresponding to the functional layer 4, the part 3-3 corresponding to the outer resin frame, the left part of the connecting section corresponding to the electrode layer 4-1, and the right part of the connecting section opposed to this in the horizontal direction.
The releasing layer 3, the functional layer 4 and the intermediate layer are formed by coating a pattern on the film 2 using a screen printing, a relief printing, a gravure printing or the like.
The functional layer 4 is formed by coating conductive ink, piezoelectric material, or dielectric material so as to form a pattern. The intermediate layer functions to strengthen coupling between the releasing layer 3 and the functional layer 4 and thus is not required if the coupling therebetween is strong.
The functional layer 4 can be formed on a pattern-protected film top surface by using a vacuum apparatus (e.g., a sputtering apparatus, an evaporation apparatus). Also, it can be formed by coating and shaping a conventional functional layer on the surface of the film 2. Alternatively, by etching a semiconductor substrate of silicon, SiO2 or the like, a large amount of the functional layers may be formed in advance and these functional layers may be adhered to the surface of the releasing layer 3 at a predetermined position of the film 2 via an adhesive layer for example. This adhesive layer is also coated on the releasing layer 3 so as to form a pattern using a screen printing, a relief printing, a gravure printing and the like.
The releasing layer 3 is formed of for example water-repellent resin (e.g., silicone resin) and functions to provide a smooth separation even when molten resin which is closely contacted with the layer 3 cures. The releasing layer 3 may be formed by any resin or inorganic matter so long as the resin or inorganic matter shows a water-repellent property when the contact angle is measured by pure water.
(2) Die 1
The die 1 is used to form a structure including a motion space for allowing, for example, the piezoelectric layer of the functional layer 4 to realize the piezoelectric element function. In the present embodiment, as shown in
The die can be formed by a silicon substrate, stainless, silicone carbide, glassy carbon, glass or nickel, iron, aluminum, dielectric material such as silicon nitride or the like. The die can be manufactured by using machining or semiconductor processings.
(3) Molten Resin Injection
As shown in
The die 1 and the film 2 have thereon alignment markers. By superposing these marks as shown in
(4) Separation of Film 2
Next, as shown in
During the separation, the cured resin 5-2 at the lower side of the releasing layer 3 is easily released and remains in the die 1 while retaining the functional layer 4. However, the parts corresponding to the upper and lower U-like parts 5-1 and the part corresponding to the outer periphery-side convex section 1d do not have the releasing layer 3. Furthermore, the convex sections 1b and 1d of the die 1 extrude the ultraviolet cure resin 5 to provide a very-thin layer. Thus, the very-thin layer and the film 2 are released while the very-thin layer is strongly adhered to the film 2.
During this, as described above, the center concave section 1a and the concave section 1c for forming a frame are connected by the concave section 1e having a narrow width provided to correspond to the electrode layer 4-1 of the functional layer 4 and a part opposed to this. This part also has the releasing layer 3. Thus, the resin filled in the center concave section 1a and the resin filled in the concave section 1c remain in the die 1 while being connected and supported by the resin filled in the concave section 1e. The resin 5-1 of the upper and lower U-like parts not having the releasing layer 3 is separated together with the film 2.
For the alignment of the film 2, when the tip ends of the inner edge and the outer edge of the respective convex sections 1b and 1d of the die 1 are formed to have a blade-like shape so as to correspond to the inner edge and the outer edge of the releasing layer 3 of the film 2, the boundary between the resin separated together with the film and the resin remaining on the die 1-side can have a blade-like shape concave section and thus the separation therebetween can be performed more securely, thus realizing the manufacture of a smaller MEMS.
(5) Ejection from Die 1
As shown in
In the present embodiment, the two opposed convex sections 1b were used to connect a part corresponding to the piezoelectric layer or the high-dielectric material layer for example to the frame by the resin filled in the concave section 1c. However, another configuration also may be used depending on the MEMS function for example as shown in
In an actual manufacturing process, a plurality of dies 1 are arranged in lengthwise and crosswise directions to form a die aggregation. The releasing layer 3, the functional layer 4 and the like are coated in lengthwise and crosswise directions so as to form a pattern on a film having the same shape and size as those of this die aggregation, correspondingly to the respective dies 1. Then, the front face of the die aggregation is coated with the ultraviolet cure resin 5 using a roller or the like. In addition, the film 2 is positioned with respect to the die aggregation. Well-known vacuuming for example is used to provide a close contact between the film 2 and the die aggregation while preventing bubbles from being mixed, thereby forming many MEMS elements simultaneously. The die aggregations may be formed in the lengthwise and crosswise directions by subjecting a flat plate of the above-described die material to a machining process or a semiconductor processing process to form many dies 1 in the lengthwise and crosswise directions. The single die 1 forms a single element in the die aggregation. Alternatively, many dies arranged in the in lengthwise and crosswise directions may be integrated to have a flat panel-like shape by heat-resistant and durable resin such as carbon fiber reinforced plastic.
In this case, the convex section 1d of each die 1 may have an adjusted height and the thin resin layer of this part connects the respective MEMSs so that the respective MEMSs can be removed from the die aggregation. Thus, the respective MEMSs can be separated at a stage for manufacturing the apparatus using MEMS. In order to achieve an easy separation of the connecting sections of the respective MEMSs, blade-like shape projections may be provided so as to form a separation line at the boundary of the convex sections 1d of the respective connected dies 1.
In the present embodiment, the film 2 was formed by ultraviolet light-transmissive resin and the ultraviolet light was emitted through the film 2. However, when the die 1 is formed by ultraviolet light-transmissive material such as glass, ultraviolet light-transmissive material maybe emitted via the die 1 to cure the ultraviolet cure resin 5.
In the first embodiment, ultraviolet cure resin was used. However, in this embodiment, an example as shown in
The second embodiment is common to the first embodiment in that the die 1, the film 2, as well as the functional layer 4, the intermediate layer, and the releasing layer 3 printed and formed on the film 2 have the same configurations as those of the first embodiment.
As shown in
Next, as shown in
When the molten thermoplastic resin is cooled and cured, the mold opening is performed as shown in
In the first and second embodiments, an example has been shown in which ultraviolet cure resin and thermoplastic resin were used as resin. However, thermosetting resin also may be used. In this case, a transfer molding for example maybe used by using the same procedure as that of the first embodiment to inject molten thermosetting resin into the die 1 to heat, instead of ultraviolet light illumination, the resin by a heater provided in the die 1. In this case, the die 1 must be made of such material that has a high thermal conductivity (e.g., stainless). When thermosetting resin is used, the resin can be sent through a reflow process, thus providing an advantage of the integration with a semiconductor element.
Furthermore, the functional layer 4 can have different configuration and pattern depending on a MEMS element to be manufactured and can have various functions.
For example, in the case of a MEMS actuator element by an electrostatic force, the only required element is an electrode layer. Thus, a MEMS element can be prepared by using a film obtained by constituting an electrode layer on the top face of a releasing layer.
In the case of a MEMS actuator using a piezoelectric element or a power generation element, a MEMS element having the minimum required configuration can be prepared by using a film obtained by forming an electrode layer/piezoelectric layer/electrode layer on the top face of a releasing layer.
In the case of a MEMS actuator using a magnetic force, such a film may be used that has an electrode layer and a magnetic layer on the top face of the releasing layer. In the case of a MEMS actuator to be deformed by heat generation, such a film may be used that has an electrode layer and a heat generation layer on the top face of the releasing layer.
The electrode layer may be made of PEDOT, conductive ink, a thin metal film for example.
The piezoelectric layer may be made of polyvinylidene fluoride (PVDF), PZT, phase-change material, crystal (SiO2), zinc oxide (ZnO), Rochelle salt (KNaC4H4O6), lithium titanate (LiNbO3), lithium tantalate (LiTaO3), lithium tetraborate (Li2B4O7), langasite (La3Ga5SiO14), aluminum nitride, or tourmaline for example.
The filling resin used in the molding step includes various resins such as ultraviolet light cured resin, thermoplastic resin, or thermoset resin (e.g., epoxy resin, acrylic, polycarbonate, ZEONOR, ZEONEX, nylon).
The MEMS structure also can be formed by curing metal. The molding step can be performed by various molding methods including heat imprinting, UV imprinting, injection molding, transfer molding, or press molding.
Alternatively, a water-repellent resin (e.g., silicone resin) was used for the demolding film in order to promote the physical peeling of the cured ultraviolet cure resin due to ultraviolet light passing through the film 2. However, the invention is not limited to this. Another resin also may be used that is selectively molten to specific solvent.
Specifically, in Embodiment 1, in order to correspond to the MEMS functional layer 4 including the electrode layer 4-1 and a layer (e.g., a piezoelectric layer, a high-dielectric material layer) and a frame for supporting this part, the releasing layer 3 is formed by using an organic film (e.g., resist, acrylic, polyester resin) to emit, after the completion of the alignment of the die 1 and the film 2 and the pressure-bonding therebetween, ultraviolet light from above the film 2 to use ultraviolet light having passed through the film 2 to cure the ultraviolet cure resin 5 to subsequently release the film 2 by immersing the entire die 1 including the functional layer 4 and the frame for supporting this part into organic film solution (e.g., resist, acrylic resin, polyester resin) dissolved in solvent (e.g., water, ethanol isopro alcohol, acetone, toluene, ethyl acetate, hexane, methyl chloride ketone). This solution enters a gap between the die 1 and the film 2 and has no influence on the functional layer 4 and the electrode layer 4-1 and the ultraviolet cure resin 5. This solution selectively causes resist only the releasing layer 3 formed by resin (e.g., acrylic resin, polyester resin) to be selectively molten without applying a physical releasing force to the film 2. Thus, the functional layer 4 and the electrode layer 4-1 can be prevented from receiving a physical impact and the film 2 can be released from the die 1 very smoothly.
In this manufacture example, a MEMS was manufactured based on the following procedure.
The subsequent steps are the same as those of the (4) and (5) of (actual manufacture example 1).
According to the investigation result of the characteristics of the MEMS structure formed in the manner as described above, a hysteresis characteristic as a piezoelectric element and a characteristic as a tactile sensor (touch sensor, vibration sensor) could be confirmed.
It is expected that MEMS will be used for various technical fields and products in the future. As described above, the micro-electromechanical system manufacture method of the present invention as well as a die and a film used for this manufacture method can eliminate the vacuum process and many manufacture steps and can use a general resin molding (e.g., compressive molding, injection molding, transfer molding) to mass-produce MEMSs having various functions through simple steps, thus significantly reducing the MEMS manufacture cost.
While the present invention has been described with reference to exemplary embodiments, it is to be understood that the invention is not limited to the disclosed exemplary embodiments. The scope of the following claims is to be accorded the broadest interpretation so as to encompass all such modifications and equivalent structures and functions.
Number | Date | Country | Kind |
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2010-152425 | Jul 2010 | JP | national |
This application is a continuation-in-part application of PCT application No. PCT/JP2011/064935 under 37 Code of Federal Regulations §1.53(b) and the said PCT application claims the benefit of Japanese Patent Application 2010-152425, filed Jul. 2, 2010, which is hereby incorporated by reference herein in its entirety.
Number | Date | Country | |
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Parent | PCT/JP2011/064935 | Jun 2011 | US |
Child | 13732655 | US |