KR101210497B1 - Micro vehicle using a magnetostrictive phenomenon - Google Patents

Abstract

The present invention is manufactured by the MEMS process, but the magnetic strain thin film corresponding to the top and bottom and the magnetic strain thin film adjacent to each other by depositing the material of different areas to select the front or rear by using the resonance frequency of the remote controller The present invention relates to a miniature movable body using a movable magnetostriction phenomenon, the configuration comprising: a plate of a predetermined material; A plurality of walking means vertically formed on the bottom surface of the plate at regular intervals; First magnetostrictive thin films formed on the upper surface of the plate at regular intervals, the positive and negative magnetostrictive thin films being alternately formed, and magnetically deforming according to an AC magnetic field applied from the outside; And magnetically deformed thin films having different properties are alternately formed at positions corresponding to the respective thin films of the first magnetostrictive thin films, alternately formed between each walking means, which is a lower surface of the plate. And second magnetostrictive thin films.

Description

MICRO VEHICLE USING A MAGNETOSTRICTIVE PHENOMENON}

1 and 2 are views illustrating a micro linear motor and an ultrasonic motor, respectively, of a conventional magnetostrictive MEMS device.

3 is a view showing a magnetostrictive miniature movable body according to the present invention.

4 and 5 are results showing the effect of the elastic energy of the magnetostrictive thin film on the measurement of the magnetostriction coefficient according to the present invention.

6 and 7 are diagrams for explaining the finite element proposed for the magnetostriction proposed by the present invention.

8A and 8B are graphs showing the analysis results performed using the finite element developed for the analysis of the magnetostrictive MEMS device according to the present invention.

DESCRIPTION OF THE REFERENCE NUMERALS

10: plate (semiconductor substrate or polyimide)

20: walking means

30: first magnetostrictive thin films

40: second magnetostrictive thin films

50: remote controller

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a micro electro mechanical system (MEMS). In particular, the present invention relates to a micro-moving body using a magnetostriction phenomenon which is manufactured by a MEMS process and is movable back and forth by an AC magnetic field of a predetermined frequency.

In general, MEMS is used interchangeably as a micro system, a micro machine, a micro mechatronics, or the like, and it is a micro electromechanical system.

There is no word that has been formally discussed and selected, but the name of the technology development task currently being developed as a leading technology business is called the development of micro precision machine technology.

Machines small enough to be unknown without a microscope are now settled out of science fiction and settle into a new field of reality engineering.

In other words, artificially create a micro robot such as an ant to try to do a minute exercise or work. In other words, it refers to a system in which various sensors corresponding to the eyes and tactiles of an ant, logic circuits corresponding to the brain and nerves, micromechanisms corresponding to arms and legs, and micro actuators that move them are combined.

The size ranges from a few mm to a few nm, and even a few cm size is often called a micromachine.

As the most important material of the MEMS, a magnetostrictive material is used, and the magnetostrictive material refers to a material in which a change in dimension (mainly called a change in length) occurs by a magnetic field applied from the outside.

The theory of magnetism was first theoretically established by Joule in 1842. In the 1960s, a large magnetostriction of about 10 ^-3 at room temperature was achieved through an alloy of rare earth elements and magnetic transition metals. Terfenol has been developed. In the 1980s, Terfenol-D was developed in MEMS in the United States, showing a large deformation under a small authorized magnetic field.

Recently, with the development of MEMS technology, researches on the fabrication and design of MEMS devices (mainly micro actuators) using magnetostrictive materials have been actively conducted. In addition, research on magnetostrictive composite materials is increasing rapidly.

Honda et al. [T. Honda, K. I. Arai, M. Yamaguchi, "Fabrication of magnetostrictive actuators using rare-earth (Tb, Sm) -Fe thin films", Journal of Applied Physics, Vol. 76, No. 10, pp. 6994-6999, 1994.] fabricated a cantilever beam in which magnetostrictive thin films such as Sm-Fe and Tb-Fe were laminated on a polyimide substrate, and the relationship between the external magnetic field and the transverse displacement of the cantilever beam By experimental observation, the applicability of the magnetostrictive material as a driving source of the micro actuator was verified.

Quandt et al. [E. Quandt, B. Gerlach, K. Seemann, "Preparation and applications of magnetostrictive thin films", Journal of Applied Physics, Vol. 76, No. 10, pp. 7000-7002, 1994.] fabricated a cantilever beam on which a 10 μm thick TbDyFe thin film was deposited on a 50 μm thick silicon thin film.

Quandt and Ludwig [E. Quandt, A. Ludwig, K. Seemann, "Giant magnetostrictive multilayers for thin film actuators", in Proceedings of Transducers '97, 1997, pp. 1089-1092.] Fabricated a TbFe / FeCo multilayer magnetostrictive thin film using sputtering method and showed experimentally that the saturation magnetostriction occurs even at a lower magnetic field than the monolayer thin film.

In addition, a cantilever actuator and a magnetostrictive micropump using multi-layer magnetostrictive thin films were fabricated and evaluated for their performance. In addition, Quadt and Seemann [E. Quadt, K. Seemann, "Magnetostrictive thin film microflow devices", in Proceedings of Micro System Technology 96, 1996, pp. 451-456. Developed a micro flow control device, Claeyssen [F. Claeyssen, N. Lhermet, J. Betz, K. Mackay, D. Givord, E. Quandt, H. Kronmller, "Linear and rotating magnetostrictive micro motors", in Proceedings of Actuators 98, 1998, pp. 372-375 et al. Manufactured a micromotor.

1 and 2 illustrate a micro linear motor and an ultrasonic motor developed by Quandt and Claeyssen, respectively, and show a magnetostrictive MEMS device.

As shown in the drawing, the conventional micro linear motor and the ultrasonic motor are driven only in one direction in response to a frequency applied from the outside.

The magnetostrictive material applied to the MEMS device has the disadvantages of very high brittleness, high eddy current loss in the high frequency band, and a relatively high magnetic field is required to obtain the desired degree of magnetostriction.

These drawbacks significantly limit the application of magnetostrictive materials, which can be overcome by constructing magnetostrictive composite materials using thermoset resins (primarily polymeric binders). That is, the mechanical toughness is improved by the thermosetting resin constituting most of the magnetostrictive composite material, and the volume of the magnetostrictive material is reduced, so that the eddy current loss and the required applied magnetic field are reduced.

Since the mid-1990s, studies on magnetostrictive composite materials have been actively conducted, and studies on analytical models for the mechanical analysis of such magnetostrictive composite materials have been actively conducted.

These studies are being conducted in a similar way to the analytical modeling technique developed for the behavior analysis of composite materials using piezoelectric materials or shape memory alloys.

Recently, research and development on the production and application of magnetostrictive thin film has been made in Korea, but it is very weak compared to the research efforts of France and Japan.

Lim et al. [S. H. Lim, S. H. Han, H. J. Kim, Y. S. Choi, Jin-Woo Choi, C. H. Ahn, "Prototype Micro actuators Driven by Magnetostrictive Thin Films", IEEE Transactions on Magnetics, Vol. 34, No. 4, pp. 2042-2044, 1998.] fabricated a cantilever-shaped micro magnetostrictive actuator and measured its performance experimentally.

They also fabricated Sm-Fe and Sm-Fe-B thin films and investigated the effects of B on their magnetic properties and magnetostriction.

In the advanced countries such as Japan, France, and the United States, research on magnetostrictive materials has been widely conducted. However, the industrial applications have the following problems.

First, researches on the magnetostrictive MEMS devices have been actively conducted, but most of them have applied the driving principle of the magnetostriction phenomenon to the microstructures and are still at the stage of concept verification for the application of the magnetostriction. In other words, specific applications and successful cases of commercialization have not been reported yet.

Although the idea of the development of magnetostrictive MEMS devices has been poorly developed or the numerical modeling techniques for the design and fabrication of magnetostrictive MEMS devices have been proposed by various researchers, the geometrical characteristics and nonlinear magnetostrictive properties of magnetostrictive MEMS devices have been suggested. It was also because they could not function as an efficient design tool that could properly consider the phenomenon.

The research on magnetostrictive composite materials is also very active, but as many studies have been done to analyze the behavior of composite materials using piezoelectric materials or shape memory alloys, magnetostrictive composite materials are effectively used as functional materials. The development of finite element modeling techniques for predicting mechanical behavior is essential for use. However, most of the studies so far have been limited to the development of analytical models, and the study of numerical modeling has not been reported yet.

Compared to other countries, domestic research on magnetostrictive materials is very weak and mainly rests on the production of magnetostrictive thin films or magnetostrictive composite materials. That is, little research has been conducted on the development of magnetostrictive MEMS devices and the modeling of magnetostrictive composite materials.

Accordingly, an object of the present invention is to deposit and form a magnetostrictive thin film corresponding to up and down on the basis of a plate of a micro-moving body with different materials and by using different resonance frequencies for a magnetic field of a predetermined frequency generated from a remote controller. An object of the present invention is to provide an ultra-compact moving body using a magnetostrictive phenomenon that is moved back and forth.

Another object of the present invention is to provide an ultra-compact moving body using a magnetostriction phenomenon that can be selectively moved forward or backward by using different resonance frequencies for a magnetic field of a predetermined frequency generated by a remote controller.

Technical means of the present invention for achieving the above object, in the micro-robot: a plate of a predetermined material; A plurality of walking means vertically formed at regular intervals on the bottom surface of the plate; First magnetostrictive thin films formed on the upper surface of the plate at regular intervals, the positive and negative magnetostrictive thin films being alternately formed, and magnetically deforming according to an AC magnetic field applied from the outside; And magnetically deformed thin films having different properties are alternately formed at positions corresponding to the respective thin films of the first magnetostrictive thin films, alternately formed between each walking means, which is a lower surface of the plate. And second magnetostrictive thin films.

In addition, the micro-robot, by transmitting a predetermined resonance frequency to the first magnetostrictive thin film and the second magnetostrictive thin film so that the magnetostrictive thin film is deformed up and down to move forward or backward through the walking means. A regulator is further provided.

Specifically, the plate is a semiconductor substrate or a polyimide film, characterized in that the magnetostrictive thin film is characterized in that at least two or more selected from TbDyFe, Tb-Fe, Sm-Fe, Terfenol material is used.

The first magnetostrictive thin films are different in area from the thin film adjacent to each other, and the second magnetostrictive thin films are different in area from the thin film adjacent to each other, and the first magnetostrictive thin film and the second magnetism correspond to each other through the plate. The strained thin film is characterized by different areas.

In addition, the magnetostrictive thin film is different in area and material from the adjacent thin film, the magnetostrictive thin film is characterized in that the deposition on the plate by the sputtering method.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.

3 is a view showing a micro-moving body using a magnetostrictive thin film according to the present invention, the plate 10, the walking means 20, the first magnetostrictive thin films 30, the second magnetostrictive thin films 40 And a remote controller 50.

The plate 10 is a semiconductor substrate (Si Substrate) or a polyimide film (Poly-imide Film), the walking means 20 is vertically formed at regular intervals on the bottom surface of the plate 10 and the plate 10 and Preferably, the first magnetostrictive thin films 30 are deposited on the top surface of the plate 10 at regular intervals, and the positive and negative magnetostrictive thin films are alternately formed. It is configured to self-deform in accordance with an AC magnetic field of a predetermined frequency transmitted from an external remote controller 50, and the second magnetostrictive thin films 40 are between each walking means 20, which is the lower surface of the plate 10. The magnetic strain thin films having different properties are alternately formed at positions corresponding to the respective thin films of the first magnetostrictive thin films 30, and are discharged from the external remote controller 50 according to the AC magnetic field. It is adapted to strain group.

In addition, the remote controller 50 transmits an AC magnetic field of a predetermined frequency to the first magnetostrictive thin films 30 and the second magnetostrictive thin films 40, and the magnetostrictive thin films having different resonance frequencies ( The magnetostrictive thin films 30, 40 are alternately deformed up and down with adjacent thin films by the magnets 30, 40 being selectively deformed by the AC magnetic field, and then moved forward or backward through the walking means 20. Is moved.

In addition, the first magnetostrictive thin films 30 or the second magnetostrictive thin films 40 have a resonance frequency that is magnetically deformed to an AC magnetic field applied from the outside of each of the adjacent thin films. For example, based on film 32, films 31 and 33 have different resonance frequencies. Of course, in this case, the thin films of 31 and 33 may have the same resonance frequency.

In addition, at least two or more of the magnetostrictive thin films 30 and 40 may be selected from TbDyFe, Tb-Fe, Sm-Fe, and Terfenol, and the first magnetostrictive thin films 30 or the second magnetic The strained thin films 40 may be formed to have different areas from the adjacent thin films 31-32-33 and 41-42-43, and the first magnetostrictive thin films 30 and 2 The magnetostrictive thin films 40 have different areas between the thin films 31-41, 42-42, and 33-43 corresponding to each other through the plate 10, and the magnetostrictive thin films 30 and 40 It is preferable to deposit and form on a plate by the sputtering method.

In general, most actuators in MEMS use static magnetic energy, and in order to utilize magnetic energy, magnetostriction effect of varying length by external magnetic field is used. The biggest advantage of using is that it can be controlled remotely by magnetic field. The possibility of remote control is an incomparable advantage compared to piezoelectricity, which is widely used in MEMS.

The important areas of remote control are biomedical and medical applications, which are important applications of MEMS, and it is obvious that remote control is essential for research in this field.

At the same time, the possibility of remote control causes a problem that local control is difficult. In the case of electrical control such as piezoelectricity, only the desired part can be selectively controlled, whereas remote control In this case, all the magnetostrictive substances in the region of the external magnetic field are exposed to the same magnetic field, making local control difficult. To solve this problem, if the resonant frequencies of the moving parts are designed differently through finite element analysis, the moving parts react selectively according to the frequency of the externally applied magnetic field. Therefore, local control is possible even remotely.

In the present invention, the development of three-dimensional finite element modeling technology for the design of micro sensors and micro actuators in which magnetostrictive materials (or magnetostrictive materials) are mainly applied in a thin film form, magnetostrictive composite Factors such as the design of the material and the construction of finite element models for the analysis of mechanical properties are also of great importance.

In addition, since the fabrication of MEMS requires complex photolithography or three-dimensional stereography, the approach to solve the problem after manufacturing is very expensive. Design using analysis is a very important field. In particular, in order to be able to remotely control the biological and medical applications, which are increasingly important among MEMS application fields, it is required to manufacture MEMS using magnetostrictive materials. Because of its nonlinear behavior, accurate prediction is difficult.

Accordingly, a three-dimensional finite element analysis model was developed for the analysis of static deformation.

For application as a micro actuator, an external magnetic field is applied so that saturation magnetostriction or large deformation of the magnetostrictive thin film is generally generated, which causes magnetostrictive hysteresis. . Therefore, for the design of the magnetostrictive MEMS device, a function that can consider the magnetostrictive history is required. In addition, the ability to account for geometric nonlinearities due to large deformations is also required.

In addition, mechanical-magnetic coupling analysis is required for the analysis of magnetostrictive MEMS devices, and the finite element models proposed for the magnetostrictive analysis have been based on node-based elemental analysis. Doing. However, in the case of magnetic field analysis, such finite element modeling is known to have some disadvantages.

That is, firstly, the results of physically invalid analysis that do not satisfy the divergence theorem can be obtained, and secondly, it is difficult to define boundary conditions, and finally, the singularities of the magnetic field at edges or corners If the analysis domain has such a structure, difficulties arise. Because of these difficulties, vector finite elements have been developed and successful interpretations have been reported. Therefore, in the present invention, a hybrid element using a conventional finite element must be developed for the stress analysis using a vector element.

Since most magnetostrictive MEMS devices have a two-dimensional shape, most of them are sufficiently analyzed using two-dimensional finite element models or axisymmetric finite element models when only stress analysis is considered or indirectly considering the self-mechanical coupling effect. However, when directly considering the self-mechanical coupling effect, three-dimensional finite element analysis is required.

In addition, the three-dimensional finite element analysis model for dynamic analysis in the high frequency region, magnetostrictive MEMS devices such as micromotors and micropumps using magnetostriction generally operate in the high frequency region. Therefore, designers of magnetostrictive MEMS devices should understand mechanical behaviors such as eddy current loss, magnetic loss, mechanical vibration and damping.

In the present invention, a finite element model capable of performing magnetic and mechanical analysis in the high frequency region is developed, and a magnetostrictive MEMS device is fabricated to verify the developed three-dimensional finite element analysis code for the analysis of the magnetostrictive MEMS device. will be.

This verification is necessary because the results of the theoretical studies on the micro magnetostriction are very poor, and the geometrical forms of the theoretical analysis objects are also very limited and thus they are not an effective verification tool.

In addition, the experimental studies of previous researchers do not serve as a direct verification tool because they do not provide enough data to verify the finite element model. For this reason, the present invention fabricates a magnetostrictive MEMS device for effective reliability verification of the magnetostrictive finite element analysis.

When manufacturing the magnetostrictive MEMS device, it is preferable to deposit and form the magnetostrictive thin film on the plate of the MEMS device by sputtering.

Through such modeling and process, we developed a micro mover with magnetostrictive thin film of the present invention. Accurate magnetostrictive coefficient measurement of magnetostrictive thin film is very important in the design of MEMS actuators that apply magnetostrictive phenomena. .

The magnetostriction coefficient can be measured by measuring the lateral displacement of the cantilever beam on which the magnetostrictive thin film to be measured is deposited because the lateral displacement of the cantilever beam is linearly dependent on the magnetostriction coefficient.

Until recently, theoretical studies to express the lateral displacement of cantilever beams more accurately as a function of magnetostriction, elastic modulus, and Poisson's ratio have been continuously conducted. However, most of these studies assume that the elastic energy of the magnetostrictive thin film can be ignored because the thickness of the magnetostrictive thin film is much smaller than that of the substrate.

However, the validity of these assumptions has not been verified so far, and the present applicant has applied the theoretical formula considering the elastic energy of the magnetostrictive thin film to the magnetostrictive thin film shown in the literature to calculate the magnetostriction coefficient, The validity of the above-mentioned assumptions is considered by comparing with the magnetostriction coefficient in case of neglect.

Through the present invention, it can be concluded that the general assumption that 'the elastic energy of the magnetostrictive thin film can be ignored because the thickness of the magnetostrictive thin film is much smaller than that of the substrate' is not always correct. 5 shows representative results for the research and development.

TbDyFe / Si Tb-Fe / Polyimide Sm-Fe / Polyimide ξ 20 2 2 ζ 0.52 19.5 10.3 η 9.8 45.4 29.9 β 0.6392 0.6634 0.6634

는 박막과 기판의 두께의 비,

는 박막과 기판의 탄성에너지의 비,

는 자기변형 상수의 계산오차이다.only,

Is the ratio of the thickness of the thin film and the substrate,

Is the ratio of the elastic energy of the thin film and the substrate,

Is the calculation error of the magnetostriction constant.

4 and 5 show the results of the influence of the elastic energy of the magnetostrictive thin film on the measurement of the magnetostriction coefficient. In the cantilever, a magnetostrictive thin film of TbDyFe material is deposited on a semiconductor substrate (Si), and polyimide A magnetostrictive thin film of Tb-Fe material was deposited on a substrate, and a magnetostrictive thin film of Sm-Fe material was deposited on a polyimide substrate, and then experimented to obtain a result of magnetic field and magnetostriction coefficient as shown in FIG. 5.

In Table 1, the magnetostrictive thin film was formed by experimenting with TbDyFe, Tb-Fe, and Sm-Fe materials, but in the present invention, the Terfenol material may be used as the magnetostrictive thin film.

6 and 7 illustrate a finite element proposed for the magnetostriction proposed by the present invention. FIG. 6 shows a beam element, and FIG. 7 shows a plate element. element).

A one-dimensional beam element is proposed for the displacement analysis of a multilayer thin-film self-deformable cantilever beam consisting of several magnetostrictive thin films.

Through this factor, the anisotropy of magnetostriction can be directly considered using the concept of equivalent magnetostrictive stress, and the flexural stiffness of the substrate on the deflection of the magnetostrictive thin film can be considered. In addition, in order to consider the effect of the width of the cantilever beam on the out of plane deformation and the bending of the beam that cannot be considered as the beam element, a plate element that extends the concept applied to the one-dimensional beam element in two dimensions is shown in FIG. 7. It is suggested.

8A and 8B show analysis results performed using finite elements developed for the analysis of magnetostrictive MEMS devices.

In this way, the frequency characteristics analysis according to the micro-patterns of the magnetostrictive samples having various shapes is compared with the results of the developed finite element analysis method, thereby securing the reliability of the solution of the finite element analysis method. In addition, by studying the frequency characteristics of various types of fine patterns, the magnetic deformation phenomenon can occur locally according to the frequency characteristics of the magnetic field applied from the outside.

Therefore, in the present invention, the ultra-small moving object is manufactured by the MEMS process, but the magnetostrictive thin films corresponding to the top and bottom and the magnetostrictive thin films that are adjacent to each other are deposited with materials having different areas, but the magnetic field generated by the remote controller is used. There is an advantage in that the selective movement to the front or rear using different resonance frequencies is possible.

In addition, the present invention has the advantage that the reliability of the product can be improved by manufacturing a compact mobile body based on the design technique through the finite element analysis in the MEMS using magnetostriction.

Claims (7)

In a micro robot, Plate of a predetermined material; A plurality of walking means vertically formed at regular intervals on the bottom surface of the plate; First magnetostrictive thin films formed on the upper surface of the plate at regular intervals, the positive and negative magnetostrictive thin films being alternately formed, and magnetically deforming according to an AC magnetic field applied from the outside; And It is formed between each walking means that is the lower surface of the plate, but the magnetic strain thin films of different properties are alternately formed at positions corresponding to the respective thin films of the first magnetostrictive thin films to deform in accordance with the AC magnetic field applied from the outside Including second magnetostrictive thin films; The first magnetostrictive thin films or the second magnetostrictive thin films, each of the adjacent thin film is a miniature movable body using a magnetostrictive phenomenon characterized in that the magnetic resonance is different from each other in the AC magnetic field applied from the outside. The method according to claim 1, And a remote controller for transmitting an AC magnetic field having a predetermined frequency to the first magnetostrictive thin films and the second magnetostrictive thin films to deform the magnetostrictive thin films up and down. The method according to claim 1 or 2, The plate is a miniature moving body using a magnetostrictive phenomenon, characterized in that the semiconductor substrate or polyimide film. The method according to claim 1 or 2, The first magnetostrictive thin films or the second magnetostrictive thin films, ultra-small mobile body using a magnetostrictive phenomenon, characterized in that selected from among the TbDyFe, Tb-Fe, Sm-Fe, Terfenol material. delete The method according to claim 1 or 2, The first magnetostrictive thin films or the second magnetostrictive thin films, the micro-moving body using a magnetostrictive phenomenon, characterized in that the area and the material is formed different from each other adjacent to the thin film adjacent to the top, bottom, left and right. The method according to claim 1 or 2, The magnetostrictive thin film is a miniature movable body using a magnetostrictive phenomenon, characterized in that the deposition on the plate by a sputtering method.

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