KR20010036745A - micro switches and fabrication method of the same - Google Patents

Abstract

PURPOSE: A micro switch and its manufacturing method are provided to improve the switching characteristics by mounting the several thousands of switches on a single substrate. CONSTITUTION: The micro switch manufacturing method includes the steps of forming a mold on the substrate to form the lower magnetic core(2) and depositing the magnetic material over the mold, forming the first insulating film on the front surface and forming the plane screw coil(3) over the first insulating film by using conductive material, forming the second insulating film on the front surface and forming the via molds to expose the lower magnetic core to form the magnetic core on the central and the lateral sides, depositing the magnetic material on the via molds and forming the metallic film(5) on the lateral sides to expose the central magnetic core, forming the sacrifice layer overlapped to the metallic film over the second insulating film and the central core, and forming the magnetic metallic layer(5) over the sacrifice layer and removing the sacrifice layer.

Description

Micro switches and fabrication method of the same

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to electronic systems, and more particularly, to a micro switch and a method of manufacturing driven using magnetic force.

The types of switches used today can be divided into large size mechanical switches and micro size solid switches.

The mechanical switch is a widely used component for automatic control circuitry, test equipment, and high frequency signal switching.

Unlike the mechanical switch, the solid switch is an electromagnetically operated switch, and a transistor or a diode is widely used.

In the case of the solid switch, not only the leakage capacitance is large, but also it is difficult to have a high off-state resistance and a low on-state resistance.

In contrast, the mechanical switch is capable of forming a high off-state resistance and a low on-state resistance as compared to a solid switch, and is so small that leakage capacitance is neglected.

Although mechanical switches have better characteristics than solid switches, solid switches are used more than mechanical switches.

The main reason is that the mechanical switch cannot be manufactured in a batch, and the price of the mechanical switch is not competing with the transistor or diode of the solid switch, which simultaneously produces tens of thousands of micro-size switches.

However, recent advances in micromachining have made it possible to fabricate integrated micro-sized switches that switch mechanically.

Integrated switches manufactured by the micromachined technology are classified according to the driving principle. The switches which are frequently studied are capacitive switches and magnetic switches.

The capacitive switch is switched by mechanically moving a moving metal plate using an electrostatic force, and the magnetic switch is switched by mechanically moving a moving metal plate using a magnetic force.

In particular, the magnetic switch is easily driven at a low voltage and has the advantage of switching a high current, so much research is being actively conducted.

However, the micro switch and the manufacturing method according to the related art described above have the following problems.

First, in the case of the mechanical switch is impossible to manufacture a batch, it is difficult to manufacture a low-cost switch.

Second, the capacitive switch and the magnetic switch have a complicated manufacturing process and require high driving current when the switch is driven.

Accordingly, an object of the present invention is to provide a micro switch having low cost and good characteristics by fabricating thousands of switches on one substrate through a batch manufacturing process.

1 is a perspective view of a magnetoresistive micro switch driven using a magnetic force according to the present invention;

2 is a perspective view showing a capacitive micro switch according to the present invention;

3 is a plan view of an electromagnet configured with a magnetic micro switch according to the present invention;

Figure 4 is a plan view showing a spiral coil structure according to the prior art

5 is a plan view of a magnetoresistive micro switch incorporating a moving metal plate according to the present invention;

6 is a plan view of a self-capacitance micro switch according to the present invention;

7 is a process flowchart implementing the magnetic microswitch according to the present invention.

* Explanation of symbols for main parts of the drawings

1 substrate 2 lower magnetic core

3: spiral coil 4: grounding electrode

5 metal plate 6 insulating film

7: center magnetic core 8: side magnetic core

9: signal connection 10: coupling pad

11 seed metal layer 22 hinge

A feature of the micro switch according to the present invention for achieving the above object is a lower magnetic core formed on a substrate and used as a signal connection line, and a center formed by vertically overlapping a plurality of thin plates on both sides of the lower magnetic core. And a side magnetic core, a conductive line wound around the central magnetic core, and a magnetic metal plate having a predetermined height on the central and side magnetic cores and moving up and down by a magnetic force.

A feature of the micro switch manufacturing method according to the present invention for achieving the above object is the step of forming a mold for forming a lower magnetic core on a substrate and depositing a magnetic material in the mold, the first insulating film on the front Forming a planar spiral coil using a conductive material on the first insulating film, forming a second insulating film on the front surface, and a plurality of vias to expose the lower magnetic core to form a central and bilateral magnetic core. Forming a mold, depositing a magnetic material in the plurality of via molds, and forming a metal film for a ground electrode on both side magnetic cores to expose a central magnetic core, and overlapping the metal film. Forming a sacrificial layer on the second insulating film and the exposed central magnetic core; This includes forming a magnetic material and removing the sacrificial layer to form a magnetic metal plate.

The action according to the features of the present invention is the configuration of a magnetic core with a planar spiral coil and a vertical thin plate superimposed on it, driven with low current and voltage, and a low cost switch can be manufactured through a consistent process.

Other objects, features and advantages of the present invention will become apparent from the following detailed description of embodiments taken in conjunction with the accompanying drawings.

A preferred embodiment of the micro switch and the manufacturing method according to the present invention will be described with reference to the accompanying drawings.

1 is a perspective view of a magnetoresistive micro switch driven by using a magnetic force according to the present invention, which includes a lower magnetic core 2 formed on a substrate and used as a signal connection line, and a center of the lower magnetic core 2. Center and side magnetic cores 7 and 8 formed by vertically overlapping a plurality of thin plates on both sides, conducting lines 3 wound around the central magnetic core 7, and on the side magnetic cores 8, respectively. The ground electrode 4 is formed on the ground electrode 4 and the central magnetic core 7, and is formed of a magnetic metal plate 5 that moves up and down by a magnetic force.

The magneto-resistive micro switch configured in this way is switched on and off by grounding the magnetic metal plate 5 which moves up and down by the magnetic force to the two ground electrodes 4.

2 is a perspective view showing a self-capacitive micro switch according to the present invention, wherein a lower magnetic core 2 formed on a substrate and used as a signal connection line, and a plurality of thin plates on the center and both sides of the lower magnetic core 2 are shown. Center and side magnetic cores (7) (8) formed vertically overlapping, conductive lines (3) wound around the center magnetic core (7), and ground formed on the center and side magnetic cores (7) (8) It consists of an electrode 4, an insulating film 6 formed on the ground electrode 4, and a magnetic metal plate 5 formed on the insulating film 6 having a predetermined height and moving up and down by a magnetic force.

The self-capacitance micro switch configured as described above forms an insulator or dielectric which is an insulating film 6 on the one ground electrode 4, and the capacitance changes and changes as the magnetic metal plate 5 moves up and down by magnetic force. It is switched by a change in impedance, which is the difference in capacitance.

3 is a plan view of an electromagnet configured with a magnetic microswitch according to the present invention. As shown in FIG. 3, the electromagnet is a planar spiral coil 3 as a signal layer, and magnetic cores 7 and 8 formed at the center and both sides thereof. ) And the lower magnetic core 2.

4 is a plan view showing a spiral coil structure according to the prior art. Referring to FIG. 4, a planar spiral coil 3 serving as a signal layer, a connection pad 10 for applying an external signal to the spiral coil 3, and The signal connection part 9 transmits the signal of the connection pad 10 to the spiral coil 3.

As described above, the planar spiral coil 3 according to the prior art manufactures an electromagnet having two connection pads 10 with at least three masks, that is, the planar spiral coil 3, vias, and signal connections ( 9) was required.

Therefore, since the process is not only complicated but also requires multiple layer processes, the magnetic core is difficult to come into contact with the ground electrode because the plane of the magnetic core is not planarized when the electromagnet is manufactured. Has

As described above, at least five masks are required to make an electromagnet as shown in FIG. 3, and a special process is required because the plane of the magnetic core is not smooth.

However, the planar spiral coil 3 used to make the electromagnet of the switch proposed in the present invention uses only one mask as shown in FIG. The signal connection part 9 to connect is manufactured.

Then, at the same time as the manufacture of the magnetic cores 7 and 8 formed at the center and both sides, a via connection part for electrically connecting the planar spiral coil 3 and the signal connection part 9 is manufactured.

Therefore, only three masks are required to form the electromagnet as shown in FIG. 3, and the planarization of the magnetic core is also very good when manufacturing the ground electrode.

3A and 3C increase the magnetic moment by dividing the central and bilateral magnetic cores 7 and 8 of the structure shown in FIG. 3B in the vertical direction, thereby increasing the shape anisotropy. This has the effect of increasing the total magnetic force required to move the moving metal plate up and down.

In addition, in order to increase the total magnetic force, it is necessary to magnetize the magnetic core. Although the lower magnetic core 4 shown in FIG. 3B can be easily flattened in the horizontal direction, the magnetic cores 7 and 8 of the center and both sides are Due to its structure, demagnetizing force in the vertical direction is so large that planarization is difficult.

However, as shown in FIGS. 3A and 3C, the magnetic cores 7 and 8 of the center and both sides can be easily flattened to form flat pieces, thereby greatly increasing the total magnetic force even at a low driving current.

In addition, in the case of FIG. 3A, the lower magnetic core 4 is composed of one wide plate, while in the case of FIG. 3C, the lower magnetic core 4 has a plurality of rod shapes to increase the magnetic force according to the magnetic moment. Larger.

5 is a plan view of a magnetoresistive micro switch incorporating a moving metal plate according to the present invention.

Referring to FIG. 5, after the electromagnet is formed, two ground electrodes 4 having conductivity are formed and formed with an air gap thereon to form a magnetic metal plate 5 that moves up and down by magnetic force.

At this time, the hinge 22 holding the magnetic metal plate 5 can be modified in number and position as shown in FIGS. 5A, 5B and 5C.

The coupling pad 10 is connected to the substrate to apply an external signal to the magnetic metal plate 5.

6 is a plan view of a self-capacitance micro switch according to the present invention.

In the resistive switch shown in FIG. 5, there are two separate conductive ground electrodes 4, while in the capacitive switch shown in FIG. 6, one conductive ground electrode 4 and an insulating film are formed on the ground electrode 4. An insulator or a dielectric is formed by (6).

A magnetic metal plate 5 is formed on the insulating film 6 with a predetermined height and moves up and down by a magnetic force.

7 is a process flowchart implementing the magnetic microswitch according to the present invention.

First, as shown in FIG. 7A, the metal seed layer 11 is formed on the insulating substrate 1, and then polyimide or PSG (PhosphoSilicate Glass), which is an insulating layer 12, is coated and cured.

In this case, when the substrate 1 is a silicon substrate, an insulating film is formed on the substrate, and then the metal seed layer 11 is formed.

And a mold for forming a signal connection line for connecting the lower magnetic core 13 and the planar spiral coil 15 is formed.

Subsequently, as shown in FIG. 7B, the lower electrode 13 is formed by depositing NiFe alloy (alloys) or another magnetic material using electroplating on the formed mold.

As shown in FIG. 7C, polyimide or PSG (PhosphoSilicate Glass), which is an insulating film 14, is coated and cured on the entire surface, and a thick photoresist is formed and patterned as a sacrificial layer to form a mold.

Cu, Au, Ag, or other conductive material is deposited using the electroplating in the mold to form a planar spiral coil 15.

Subsequently, as shown in FIG. 7D, a polymer or PSG, which is an insulating film 16, is thickly coated and cured to have a flat surface.

And a via mold for connecting the planar spiral coil 15 and the signal conducting line 13 to the center and side magnetic cores 17 to be produced.

Subsequently, as shown in FIG. 7E, the formed via mold is deposited using NiFe alloys or other magnetic materials using electroplating, thereby forming the center and side magnetic cores 17.

Then, after coating and curing the insulator on the front surface as shown in FIG. 7F, the conductive ground electrode 18 is formed using Au, Ag, or Cu having high conductivity by using electroplating or sputtering.

At this time, the ground electrode 18 is formed on both side magnetic cores, and the central magnetic core is exposed.

As shown in FIG. 7G, the sacrificial layer 19 is formed on the exposed central magnetic core by overlapping the ground electrode 18.

In this case, the sacrificial layer 19 is deposited by any one of photoresist, PSG, or Cu, Al, and Ni.

Subsequently, as shown in FIG. 7H, a thick photoresist is formed and patterned as a sacrificial layer to form a mold for the moving magnetic metal plate.

The magnetic metal plate 20 is formed by depositing NiFe alloys or other magnetic materials using electroplating in the mold.

As shown in FIG. 7I, a micro switch in which the magnetic metal plate 20 is moved in the air by removing the sacrificial layer 19 is manufactured.

In this case, when the self-capacitance micro switch is made, the process is the same as the process of making the resistive switch. In the process of FIG. It is formed on the ground electrode 21 so that the center and both magnetic cores 17 are included.

And it is made in the same manner as the steps 7g, 7h, 7i.

Thus, the structure and operation principle of the micro-switch according to the present invention is summarized as follows.

The structure of the micro switch is composed of an electromagnet, a metal plate moving up and down, and a conductive ground electrode.

The operation of the micro switch configured as described above is as follows.

The conductive ground electrode is connected to external electrical systems and controlled by an electromagnet switch.

In the electromagnet, magnetic flux is generated by passing a current through a planar spiral coil.

The magnetic magnetic plates floating in the air move up and down by the generated magnetic flow.

In addition, the vertically moving metal plate is brought into contact with two conductive ground electrodes respectively formed on the electromagnet, thereby switching occurs.

The micro switch and the manufacturing method according to the present invention as described above has the following effects.

First, by adopting a CMOS compatible process, thousands of switches can be simultaneously manufactured on a single substrate through batch manufacturing, so that a switch having good characteristics at low cost can be produced.

Second, the planar magnetic coil can be used to simplify the manufacturing process. Also, since a vertical thin plate of superimposed magnetic core is used, it can be driven with low current and voltage.

Those skilled in the art will appreciate that various changes and modifications can be made without departing from the spirit of the present invention.

Therefore, the technical scope of the present invention should not be limited to the contents described in the embodiments, but should be defined by the claims.

Claims (10)

A lower magnetic core formed on the substrate and used as a signal connection line, Center and side magnetic cores having a predetermined shape on the center and both sides of the lower magnetic core, A conduction line wound around the central magnetic core, And a magnetic metal plate formed on the center and side magnetic cores having a predetermined height and moving up and down by a magnetic force. The method of claim 1, And a ground electrode formed on each of the two magnetic cores. The method of claim 1, A ground electrode formed on the center and both magnetic cores; And an insulating film formed on the ground electrode. The method of claim 1, The center and the side magnetic core is a micro switch, characterized in that consisting of a plurality of thin plates vertically overlapping. Forming a mold for forming a lower magnetic core on a substrate and depositing a magnetic material in the mold, Forming a first insulating film on the entire surface and forming a planar spiral coil using a conductive material on the first insulating film, Forming a plurality of via molds so as to expose the lower magnetic cores to form a second insulating film on the front surface and to form the central and opposite magnetic cores; Depositing a magnetic material in the plurality of via molds and forming a metal film for a ground electrode on both sides of the magnetic core so that the central magnetic core is exposed; Forming a sacrificial layer over the metal layer and overlapping the second insulating layer and the exposed central magnetic core; and And forming a magnetic material to remove the sacrificial layer to form a magnetic metal plate moving on the sacrificial layer. The method of claim 5, And forming a metal film on the entire surface and forming an insulating film on the metal film. The method of claim 5, The method of claim 1, further comprising the step of forming a seed metal layer on the substrate. The method of claim 5, And said magnetic material is made of a NiFe alloy. The method of claim 5, The metal film for the ground electrode is a manufacturing method of a micro switch, characterized in that formed of any one of Cu, Au, Ag. The method of claim 5, The first and second insulating film is a method of manufacturing a micro switch, characterized in that formed of either polyimide or PSG (PhosphoSilicate Glass).