KR100591862B1 - Micro-Driver Using SiSiO Substrate and Manufacturing Method Thereof - Google Patents

Abstract

The microminiature driver consists of a junction of a glass substrate on which a lower electrode is formed and a single crystal silicon substrate on which a movable structure is formed. The movable structure is composed of a flat plate-shaped upper electrode and an elastic member having a bent structure. The movable structure uses the electrostatic force generated when a voltage is applied between the upper and lower electrodes and the restoring force of the elastic member as a driving force in the out-plane direction perpendicular to the substrate. To drive. Such micro drivers are constructed by joining a glass substrate and a single crystal silicon substrate using an anodic bonding technique. In addition, the chemical mechanical polishing (CMP) process can be used to adjust the thickness of the movable structure as desired. A photosensitive agent is used as a mask to form a movable structure pattern, and a single crystal silicon substrate is vertically etched to form a final movable structure.

Micro-Electro-Mechanical System (MEMS), RF Switch, Monocrystalline Silicon

Description

The Micro-Electro-Machine Using SiOG Substrate and manufacturing method of the same}

1A is an overall perspective view of a direct contact series switch proposed in the present invention.

Figure 1b is a view showing a perspective view and a cross-section of the linear spring proposed in the present invention.

2A to 2I are cross-sectional views taken along the line AA ′ of FIG. 1A to illustrate the fabrication process of the silicon MEMS switch proposed in the present invention.

3A is an electron scanning micrograph of a direct contact series switch.

3B is a graph showing a switch shape measurement result using a 3D profiler.

4 is a graph showing threshold voltage distributions for 18 switches arbitrarily selected in a substrate fabricated using the present invention.

Figure 5 is a graph showing the measurement results of the signal transmission characteristics of the four direct contact type series switches manufactured using the present invention.

Figure 6a is a graph measuring the change in the signal separation according to the input power in the switch off state for a frequency signal of 2kHz.

Figure 6b is a graph measuring the output power when the switch ON / OFF drive while increasing the input power.

7a to 7b show the results of observing the waveform of the input signal transmitted to the output through the oscilloscope.

* Description of the symbols for the main parts of the drawings *

100: first substrate 10: silicon substrate

11 insulating film 12 contact portion

13: movable structure 14: elastic member

15: fixed support 200: second substrate

20: glass substrate 21: insulating film

22: signal line 23: ground wire
17: upper silicon structure

The present invention relates to a micro-driver using a SiOG (Silicon-on-Glass) substrate and to a method for manufacturing the same, and more particularly to manufacturing a micro-driver such as an RF MEMS switch using a SiOG substrate combined with a single crystal silicon and a glass substrate And a microdriver manufactured therefrom.

MEMS (Micro-Electro-Mechanical Systems) technology is a technology for manufacturing microstructures, ultra-small sensors, and micro actuators that combine electrical and mechanical components using established micro-semiconductor manufacturing processes. Beginning with the manufacture of simple gears with size, the fields such as Bio, Optic, RF, IMU (Inertial Measurement Unit) have been subdivided, and research is being actively conducted.The surface micro-technology commonly used by micromachining technique ( Based on surface micromachining and bulk micromachining, it is securing its position as a unique technology. MEMS technology is expanding its application range due to the advantages of low power, high efficiency, and high performance unit devices or integrated (IC) systems.

In particular, since the 1990s, with the rapid development of the information and communication field, the continuous development of wireless communication systems used in high frequency bands such as IF and RF bands due to the depletion of existing frequency bands. However, the existing Microwave Integrated Chip (MIC) or Monolithic Microwave Integrated Chip (MMIC) has difficulty in wideband operation at high frequencies, and their use is limited due to their large loss and nonlinearity. Therefore, there is an urgent need for research on RF MEMS devices to solve general problems occurring in existing high frequency devices.

In particular, the RF switch in such a wireless communication system is actively researched as a key component that has a decisive effect on the performance of the device. Conventional switching devices, such as P-I-N diodes or field effect transistors (FETs), have narrow frequency bands, have high loss and power consumption at high frequencies, and have interference distortion phenomena due to their nonlinearity. In comparison, RF MEMS switches are capable of wideband operation up to 120 하며 and have low loss and power consumption at high frequencies. In addition, the bias network is simple, and the linearity increase due to the replacement of some of the electrical components by mechanical structures can reduce the effects of interference distortion. These advantages make RF MEMS switches an alternative to conventional electrical components in the high frequency band.

RF MEMS switches reported to date are mainly used as a structural material, metals such as gold, copper, nickel, aluminum, etc., and many technologies are integrated in wafer units. However, there are still some problems to be solved for such a MEMS switch to be commercially available. One of the major problems is device reliability. The fabrication of existing MEMS switches using metal as a structural structure is usually performed by depositing a thin film at a high temperature and removing the sacrificial layer through ashing to float the structure. The stress may cause the structure to bend or deform, deteriorating the switch characteristics or, in the worst case, to be unable to be used as a switch, which may result in a significant decrease in fabrication yield and device reliability.

In order to solve this problem, the material forming the switch structure is replaced with a material having good temperature characteristics and not affected by external stress. Single crystal silicon, a material widely used in the semiconductor manufacturing process, has very good thermal properties, and there is no plastic deformation or creep phenomenon below 800 ° C, little residual stress or stress gradient, and can withstand excessive mechanical and thermal external environments. As a material having an advantage, it is a material that can replace the metal used as a structural material in the existing MEMS switch.

The present invention manufactures a switch using single crystal silicon instead of a metal that has been mainly used as a switch structure material, thereby increasing the mechanical reliability of the device as well as facilitating the fabrication and excluding the structure deformation by excellent thermal properties. The purpose is to achieve uniformity of properties.

As a construction means for achieving the above object, the present invention comprises the steps of providing a first substrate and a second substrate consisting of a single layer; Bonding the first substrate and the second substrate; Polishing the bonded first substrate to adjust the thickness; And forming a movable structure on the polished first substrate; It is to provide a method of manufacturing a micro-driver comprising a.

The first substrate and the second substrate may be made of single crystal silicon and glass, respectively. In this case, in the bonding of the first substrate and the second substrate, it is preferable to use an anode bonding method. In addition, the step of adjusting the thickness by grinding the bonded first substrate is preferably carried out by polishing the first surface of the first substrate using a chemical mechanical polishing (CMP) process.

More preferably, forming a gold thin film for pad formation on the polished first surface of the first substrate; And forming an etching mask on the first surface of the first substrate on which the pad is formed by using a photoresist and anisotropically etching to form a pattern of the movable structure. Further preferably, the movable structure of the first substrate may be driven in an out-of-plane direction perpendicular to the substrate and in an in-plane direction parallel to the substrate. Alternatively, the movable structure of the first substrate may be formed to be driven in an out-of-plane direction perpendicular to the substrate and in an out-of-plane direction perpendicular to the substrate.

Preferably, before the step of bonding the first substrate and the second substrate, forming a contact portion on the first substrate; And forming a signal transmission line and a fixed electrode on the second substrate in contact with and in contact with the contact portion to transmit a signal. More preferably, the forming of the contact portion on the first substrate may include forming a cavity on the first substrate by using dry and wet etching processes; Patterning an insulating film on the formed cavity center portion; And patterning a metal thin film on the formed insulating film. The forming of the signal transmission line and the fixed electrode on the second substrate may include: patterning a metal thin film on the second substrate; And patterning an insulating film on the formed metal thin film.

Preferably, the movable structure pattern is connected to the formed pad, and after the anisotropic etching, the movable structure pattern formed on the first substrate is spaced apart from the second substrate below, and the portion except for the movable structure pattern of the first substrate is 2 is bonded to the substrate, wherein the movable structure pattern connected to the formed pad may include an elastic member having an air resistance blocking hole and driving.

In another aspect, the present invention, the first portion is formed in a single layer, including a fixed portion, a movable structure elastically connected to the fixed portion, the movable structure formed to move by an electrical force, and a contact portion formed in the lower portion of the movable structure Board; And an electric force applied to the signal transmission line and the movable structure which are bonded to the fixed part of the first substrate and spaced apart from the movable structure by a predetermined distance, and which transmit and receive signals by contacting and non-contacting with the contact part. It is an object of the present invention to provide a fine driver comprising a; a second substrate comprising a fixed electrode. The movable structure of the micro driver includes a moving electrode corresponding to the fixed electrode, and the moving electrode has an air resistance blocking hole and is connected to the fixed part through a plurality of elastic members. More preferably, each of the elastic members may have a folded shape.

In addition, the first substrate and the second substrate of the micro driver may be made of single crystal silicon and glass, respectively, and the contact portion formed on the first substrate and the fixed electrode formed on the second substrate and the signal transmission line may be made of metal. . In addition, the moving electrode and the elastic member formed on the first substrate is preferably made of single crystal silicon.

In addition, the movable structure of the first substrate of the micro driver may be formed to be driven in an out-of-plane direction perpendicular to the substrate or in an in-plane direction parallel to the substrate. Alternatively, the movable structure of the first substrate may be formed to be driven in an in-plane direction parallel to the substrate and in an out-plane direction perpendicular to the substrate. In addition, the fine driver when the movable structure of the first substrate is formed to be driven in a direction out of the plane perpendicular to the substrate can be manufactured by the RF switch.

The micro driver is a driver using micromachining technology, and includes a switch for blocking and connecting a signal, a micro actuator, a micro structure, a micro sensor, and a micro driver. In the following preferred embodiment of the present invention will be described with respect to the RF MEMS switch of the micro-driver.

Conventionally, when fabricating a switch using a micromachining technique, a metal or polycrystalline silicon is mainly used as a structural material, and has been manufactured through a sacrificial layer process. However, due to the properties of the material, they cannot avoid deformation due to heat generated in the manufacturing process, and thus, it is difficult to expect the desired properties. In addition, since such deformation occurs unevenly within one substrate, there is a disadvantage that the distribution of the characteristics of the switches generated in one substrate may be uneven, which may cause a problem in the stability of the product.

In the present invention, a single crystal silicon substrate composed of a single layer is used to separately manufacture a silicon upper substrate on which a driving part and a contact part of a switch are formed, and a lower substrate on which a signal transmission line is formed, and the switches are configured by aligning and bonding the two substrates. As such, when using a single layer silicon substrate, the thickness of the driving unit can be freely adjusted and the production cost can be lowered as compared with the case of using the SOI substrate. In the present invention, since the single crystal silicon substrate is used to form the driving unit and the elastic member, there is an advantage in that deformation due to heat or external stress does not occur. Due to these characteristics, when the switch is manufactured using a single crystal silicon substrate, the electrical and mechanical properties of a plurality of switches manufactured on one substrate may be fairly uniform, thereby increasing the stability of the product during production. .

In the present invention, the driver and the contact portion 12 are formed on the silicon substrate 10 and the coplanar waveguide (CPW) is formed on the glass substrate 20 to align these two substrates, and then SiOG forming a junction using an anodic bonding technique. A switch was configured using a (Silicon on Glass) process, and a schematic view thereof is as shown in FIG. 1A. FIG. 1B is also a schematic view of the mechanical spring (elastic member) 14 used in the proposed switch. As shown in FIGS. 1A and 1B, the movable structure 14 and the contact portion 12 constituting the silicon substrate 10. ), The fixed support part 15 and the mechanical spring (elastic member) 14 are all made of a single crystal silicon material, and are aligned on a glass substrate 20 on which CPW is formed and bonded using an anodic bonding technique. Configured. The lower substrate was a glass substrate (Pyrex 7740) for anodic bonding. The relative dielectric constant of the glass substrate is 4.82, which is relatively high in dielectric loss compared to the quartz substrate, but has the advantage of being capable of sealing bonding through anodic bonding.

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The switch proposed in the present invention is driven by the electrostatic force induced between the two electrodes when a voltage is applied between the upper electrode and the lower electrode, wherein the contact metal 12 is connected between the open signal transmission line 22 By configuring the short circuit, the input signal is transmitted to the output. Since the magnitude of the voltage applied to drive the switch is proportional to the size of the electrode, in this study, the size of the electrode is designed to be relatively large compared to the electrode size of a switch using a metal to reduce the driving voltage. This is possible because of the excellent thermal properties and the material properties of silicon with little internal stress, so that no deformation occurs during fabrication. In addition, when the spring is composed of single crystal silicon, the Young's modulus is larger than that of the metal, and thus, when the spring has the same size, the spring constant is increased so that the driving voltage is increased. An attempt was made to compensate for this by introducing a spring to reduce the drive voltage. Equation 1 shows the spring constant of the mechanical spring 14 of the proposed silicon switch.

Where L is the length of the spring, t and w are the thickness and width of the spring, respectively. And E and G are Young's modulus and Shear modulus, respectively.

Gold was selected as a material for forming the contact portion 12, and the gold constituting the contact portion 12 has advantages of very low contact resistance, excellent conductivity, and good RF signal transmission characteristics. In addition, since it has a relatively high hardness, it is also an important feature that gold has a relatively small influence of surface damage caused by metal contact. Contact 12 is movable structure 13 facing contact 12 to minimize signal coupling between contact 12 and movable structure 13 when the switch is turned ON to transmit a signal. Opening the part in a grid pattern to reduce the area of direct contact between the movable structure 13 and the contact portion 12 while maintaining mechanical stability. As mentioned above, the switch proposed in the present invention determines the ON / OFF state of the switch according to whether the contact metal 12 and the signal transmission line 22 are in contact with each other. When the contact metal 12 contacts the signal transmission line 22, the contact resistance decreases as the contact area increases. However, since the adhesion may occur when the contact metal 12 is too large, the size of the contact metal 12 is designed in consideration of the advantage. In addition, the structure having a drive unit is affected by air damping during driving. Especially for smaller structures, such as MEMS structures, the impact is even greater. The air resistance coefficient is greatly influenced by the initial gap between the upper and lower parts, and as a method of reducing the influence of air degradation during driving, it is common to form a hole for reducing the air resistance in the driving unit. When the size of the driving unit is large, it becomes more sensitive to air resistance, resulting in a decrease in response speed of the switch. Therefore, in the present invention, the size of the portion in which the contact portion 12 is formed between both upper electrodes is reduced, and an air resistance lowering hole having a length of 5 μm on one side of the silicon upper electrode is arranged in an array of 20 μm intervals ( It is designed to minimize the effect of air resistance by arranging in the form of array.

There may be three ways in which the switch is driven. First, in the case of the RF switch described in the above embodiment, when a voltage is applied between the upper and lower plate electrodes, electrostatic power is applied between the two plates charged with opposite charges, and the movable structure having the upper electrode is perpendicular to the substrate. In contact with the substrate while moving out of the plane, that is, up and down.

Alternatively, the movable structure may be driven in contact with the substrate by moving from side to side in parallel with the substrate. A representative example is a comb actuator. When a voltage is applied to the support part, the attraction force is generated by the voltage applied between the opposite comb drivers so that the movable comb driver is driven in parallel with the substrate. In addition, if the applied voltage is removed, it is returned to its place by the restoring force of the elastic member.

Hereinafter, a manufacturing process of the silicon switch using the SiOG substrate proposed in the present invention will be described.

The silicon switch proposed in the present invention is fabricated using a semiconductor microprocess. Figures 2a to 2h shows the entire manufacturing process of the switch, it shows the AA 'cross-section of Figure 1a. As shown in FIGS. 2A to 2H, the silicon substrate 10, which is the first substrate 100 on which the driving part and the contact part 12 are formed, and the glass substrate, which is the second substrate 200 on which the CPW is formed, are formed before the anodic bonding is performed. 20 may be manufactured in parallel. Firstly, as a first step of fabricating a silicon substrate, a cavity was formed to pattern an initial gap between the driving unit and the CPW. The cavity was etched to a depth of 3.7 μm considering the initial spacing between the designed upper and lower electrodes and the thickness of the gold and insulating films 11 and 21 where the contact portion 12 and the signal transmission line 22 were formed (FIG. 2A). The silicon dioxide 11 for the electrical insulation between the silicon 10 and the contact metal 12 into the cavity formed by using PECVD (Plasma Enhanced Chemical Vapor Deposition, STS) method is 0.2 After the deposition, the silicon oxide layer 11 was etched using a reactive ion etching (RIE) method after defining a desired shape through a photolithography process (FIG. 2B). Thereafter, a lift-off process was performed to form the contact portion 12 on the patterned silicon oxide film 11. First, a removal mold having a thickness of 6 μm was formed using AZ4620, which is a positive photoresist. The deposition of gold used as the contact portion 12 has poor step coverage, and thermal evaporation to easily remove unnecessary metal parts. Was deposited to a thickness of 5000 mm 3). In general, gold has poor adhesion to a substrate, so chromium or titanium is used as an adhesive layer therebetween. In this study, chromium was used as the adhesive layer between gold and the substrate and its thickness was 100Å. Subsequently, only the desired contact portion 12 pattern was formed on the insulating film 11 by removing the photoresist mold and removing unnecessary metal patterns using acetone. Photoresist mold patterning and other photographic processes during the lift-off process was used MA-6 equipment from Karl-SUSS (Fig. 2c). Through the above process, the silicon substrate processing as the first substrate is completed.

Next, the first step of processing the glass substrate 20 which is the second substrate is a CPW forming process using a lift off process. As in the upper plate fabrication, the photoresist mold was first formed using the AZ4620, and then chromium and gold were deposited on the surface of the film by heat deposition. The photoresist mold was then removed using acetone to form the desired CPW pattern on the glass substrate (FIG. 2D).

Thereafter, in order to prevent an electrical short between the upper electrode and the lower electrode, the silicon oxide film 21 used as the insulating film 21 was deposited and patterned on the ground line 23 to a thickness of 0.2 μm. (FIG. 2E). After fabricating the glass substrate 200 on which the silicon substrate 100 and the signal transmission line 22 are formed through the driving process as described above, both substrates were aligned to perform anodic bonding (FIG. 2F). In this process, when the alignment between the silicon substrate 100 and the glass substrate 200 is poor, it should be noted that problems such as poor bonding or deterioration of properties after fabrication of the switch may occur. Therefore, before joining both substrates, a standard cleaning operation was performed using a solution of sulfuric acid and hydrogen peroxide in a ratio of 4 to 1 to remove foreign substances or residual polymer components from the substrate. The EVG was used as an EV501 jointer, and the bonding was performed for 7 minutes while applying a constant temperature of 350 ° C. and a voltage of 800 V.

After the bonding was completed, a thinning process of silicon was performed to define the thickness of the final structure, and the mirror surface treatment of the surface of the silicon substrate 100 was performed at the same time as the detailed thickness control was performed by using chemical mechanical polishing (Chemical Mechanical Polishing). Was performed (FIG. 2G). Controlling the thickness of silicon through silicon thinning and chemical mechanical polishing processes is a characteristic of using the SiOG process technique, which means that the driving voltage can be controlled. The etchant widely used in the process of silicon thinning includes TMAH (Tetramethylammonium hydroxide) and KOH (Potasium hydroxide).

40 w% KOH may be used as an embodiment of the present invention, in which 600 ml of distilled water and 400 g of KOH were mixed to adjust the concentration of KOH to 40 w%. The thinning process temperature was 80 ° C. and etching was carried out for 8 hours with an etching rate of 1 μm per minute. After the silicon thinning process, the fine thickness was controlled by chemical mechanical polishing and mirror-treated. The etching rate at this time is 0.9 µm per minute. After the chemical mechanical polishing process, washing is performed to remove the remaining slurry on the substrate, which is mixed in a solution of 2: 1: 1 mixed with ammonium hydroxide, hydrogen peroxide and ionized water at a temperature of 270 ° C or higher. At least 20 minutes were performed.

Thereafter, in the final fabrication process, silicon 100 is vertically etched to finally form a switch. In this case, AZ1512, a photosensitive agent having a thickness of 1.2 μm, was used as a silicon etching mask, and patterned through backside alignment. Silicon vertical etching was performed using a Plasma-therm deep silicon etcher using ICP (Inductively Coupled Plasma) method (FIG. 2H). Through the above process, the proposed silicon switch is fabricated. Although not shown, reference numeral 17 denotes the upper silicon structure.

The performance of the fabricated silicon switch is evaluated to confirm that the fabricated silicon switch shows more stable characteristics than the MEMS switch fabricated using the existing metal or polycrystalline silicon.

First of all, it was judged whether or not structural deformation occurred in the manufacturing process, which is the biggest problem of the existing metal switch, and compared with the existing metal switch, the possibility of improvement in the uniformity of manufacturing and performance, mechanical reliability, and stability was examined. The electromechanical properties of the fabricated silicon switch were measured.

Electron scanning microscope (SEM) and 3D profiler were used to determine whether the structure was deformed after fabrication. 3A is an electron scanning microscope measurement result of the manufactured switch. As can be seen in the photograph, the structure was very flat and no deformation was observed. And 3b is a result of measuring the shape of the silicon switch manufactured using a three-dimensional profiler in order to support the electron scanning microscope measurement results of FIG. 3a. In addition, no deformation was observed in the structure, and it was confirmed that the switch driving part and the elastic member part were made very stable at the same height. This means that when the single crystal silicon is used as the structural material of the switch, it is not affected by heat or residual stress generated in the manufacturing process, and thus, a stable manufacturing result can be obtained.

 Next, the distribution of the driving voltages of 18 switches manufactured on the same substrate was examined to determine the uniformity of the driving voltages of the manufactured switches. In the case of the silicon switch proposed in the present invention, the ON state and the OFF state are controlled by driving the switch by using a constant power generated by a voltage applied between the upper electrode formed on the silicon substrate and the lower electrode formed on the glass substrate. do. When the voltage applied to the switch is sequentially increased, the displacement of the structure is continuously changed accordingly, and the structure reaches the unstable region at the moment when the applied voltage is equal to the threshold voltage, thereby instantaneously attaching to the lower electrode. The pull-in voltage of the switch is a voltage at which the switch structure reaches an unstable region and momentarily attaches to the lower electrode, and is generally referred to as a driving voltage. Equation 2 is derived to calculate the threshold voltage, which is derived from the equilibrium relationship between the electrostatic force driving the switch and the restoring force to return the driven structure to its original position.

Where g is the initial spacing between the electrodes, d is the displacement of the structure, t _d and r are the thickness and dielectric constant of the insulating film, and 0 is the dielectric constant of air.

4 shows threshold voltage distributions for 18 randomly selected switches within a substrate. The average threshold voltage of the 18 switches to be measured was 19.1 V with a standard deviation of 1.5 V. In addition, 12 out of 18 switches showed a difference within the standard deviation of 1.5 V, which means that a relatively uniform voltage distribution can be obtained when single crystal silicon is used as a structural member of the MEMS switch.

 In order to confirm the uniformity of signal transmission characteristics of the fabricated switches, the signal transmission characteristics of four switches of the same model were measured. In general, the signal transmission characteristics of a switch are evaluated by measuring signal isolation, which shows how well the signal is blocked in the switched-off state and insertion loss, which shows how well the signal is transmitted in the switched-on state. 5 shows the measured signal transmission characteristics, the insertion loss of the four switches showed a distribution of 0.18 dB to -0.2 dB, and the signal separation shows a distribution of 38 dB to -39 dB, with very little deviation between the switches. It can be seen that the uniform properties. This uniformity between the different switches means that the manufacture of the switch is uniform, which is an advantage that can be obtained when manufacturing the switch using silicon.

 Next, we measured the power transfer capacity and lifetime to evaluate the mechanical reliability of the switch. First of all, the power transmission capacity of an RF switch generally indicates how effectively a high-frequency signal having high power is transmitted. The switch manufactured using MEMS technology is mainly controlled by the switch ON / OFF through mechanical movement by the electrostatic force generated between the upper and lower electrodes. In the case of such a mechanical switch, the power transfer capacity is driven by the voltage generated between the upper and lower electrodes of the switch due to the high power of the input signal when the switch is turned off. actuation) or the input signal having a high power in the ON state is limited by the phenomenon of not holding the driving voltage again. As a result, a signal with more power than the switch itself or a voltage that does not return to the OFF state without removing the voltage cannot be transmitted. In this study, the mechanical power transfer capacity of the fabricated switch was measured by measuring the operating characteristics of the switch for the two factors mentioned.

Figure 6a is a graph measuring the change in the signal separation according to the input power in the switched off state for the frequency signal of 2 GHz. While the signal was applied to the input terminal of the signal transmission line and the power of the signal was increased, it was observed whether the manufactured switch was self-driven for the applied high power signal. As shown in FIG. 6A, even when the input power is increased to 34 dBm (2.5 W), it can be seen that the signal changes linearly while maintaining the initial signal separation. This means that magnetic driving does not occur even for a high power signal of 34 dBm (2.5 W). 6B shows the output power when the switch ON / OFF drive is performed while increasing the input power. When driving the switch while increasing the input signal power, it was confirmed that the signal power of 31 dBm (1.3 W) was returned to the original state when the driving voltage of the switch was removed to maintain the signal separation. As a result of measuring the power transmission capacity of the fabricated switch, it was confirmed that relatively large power could be transmitted compared to the existing metal switch. This is due to the increase in mechanical strength and resilience of the driving part by fabricating the switch structure using silicon. do.

One of the great features of devices fabricated using MEMS technology is the inclusion of a drive with mechanical movement in the structure. However, as the driving part included in the structure is repeatedly driven, a fatigue failure phenomenon, especially in the case of a device made of metal, may cause a memory phenomenon in which the shape of the driving part is permanently deformed by repeated driving. It is a factor in determining the lifetime. In the case of the direct contact switch proposed in this study, the ON / OFF characteristics of the switch are determined by the direct contact between the metal of the contact part and the signal transmission line. In this case, the mechanical characteristics of the spring may occur due to the repetitive operation of the switch. Its lifetime is determined not only by deterioration and change in contact resistance but also by adhesion phenomenon occurring between metals in contact. Therefore, in this study, the life span of the switch was predicted by observing the change of waveform, the initial gap between the upper and lower parts, and the contact resistance as the output of the switch was repeatedly driven. The oscilloscope was connected to the signal transmission line input and output of the fabricated switch to observe the change of the output waveform before and after repeat driving.

7A to 7B show the results of observing the waveform of the input signal delivered to the output through the oscilloscope. 7A to 7B, the upper waveforms represent driving voltage waveforms applied to the upper electrode, and the lower waveforms represent waveforms in which an input signal is transmitted to the signal transmission line output by a switch. In addition, Figure 7a is the initial state before the repetitive drive, Figure 7b is a waveform observed after the repetitive drive more than 10 ⁸ times. Also it has a waveform that is passed to the output 10 for more than ⁸ times after repeated running, as shown in 7 can confirm that it has not a significant change occurs. The measurements do not have 10 ⁸ times repetition driven FIG sticking phenomenon between the contact metal and the signal transmission lines over the case of the making switch occurs judging a, the output signal also switch without modification of the input tray stably driven it means. That is, it was confirmed that the mechanical stability can be increased when fabricating a switch using silicon.

In the present invention, the direct contact RF MEMS switch is designed and fabricated using single crystal silicon in order to solve the problem of the existing metal or polycrystalline silicon switch which causes deformation of the structure due to heat generated during the fabrication process and to increase device reliability. By measuring the electromechanical properties of the manufactured switches, when the switch is manufactured using single crystal silicon as a structural material, deformation does not occur during the manufacturing process, thereby increasing the uniformity of the manufacturing and characteristics compared to the existing metal switches. In addition, it has been confirmed that the mechanical reliability and stability can be improved.

Claims (23)

Providing a first substrate made of single crystal silicon and a second substrate made of glass; Bonding the first substrate and the second substrate using an anodic bonding method; Polishing a first surface of the bonded first substrate using a chemical mechanical polishing (CMP) process to adjust the thickness; And Forming an etching mask on the polished first substrate by using a photosensitive agent on a first surface of the first substrate and forming a movable structure by this method angle; Method of manufacturing a microdriver comprising a. delete delete delete delete The method of claim 1, wherein the movable structure of the first substrate is formed to be driven out of a plane perpendicular to the substrate. The method of claim 1, wherein the movable structure of the first substrate is formed to be driven in an in-plane direction parallel to the substrate. The method of claim 1, wherein the movable structure of the first substrate is formed to be driven in an in-plane direction parallel to the substrate and in an out-plane direction perpendicular to the substrate. The method of claim 1, Before bonding the first substrate and the second substrate, Forming a contact portion on the first substrate; And Forming a signal transmission line and a fixed electrode on the second substrate in contact with and in contact with the contact portion to transfer a signal; Method of manufacturing a fine driver, characterized in that it further comprises. The method of claim 9, Forming a contact portion on the first substrate, Forming a cavity on the first substrate using dry and wet etching processes; Patterning an insulating film on the formed cavity center portion; And Patterning a metal thin film on the formed insulating film; Method of manufacturing a fine driver comprising a. The method of claim 9, Forming the signal transmission line and the fixed electrode on the second substrate, Patterning a metal thin film on a second substrate; And Patterning an insulating film on the formed metal thin film; Method of manufacturing a fine driver comprising a. The method of claim 1, wherein the movable structure pattern is connected to the formed pad, and the movable structure pattern formed on the first substrate after the anisotropic etching is spaced apart from the second substrate below, except for the movable structure pattern of the first substrate. The part is bonded with a 2nd board | substrate. The manufacturing method of the micro driver. 13. The method of claim 12, wherein the movable structure pattern connected to the formed pad includes an elastic member for driving with an air resistance blocking hole. A first substrate formed of a single layer, the first substrate including a fixed portion, a movable structure elastically connected to the fixed portion, the movable structure formed to move by an electrical force, and a contact portion formed below the movable structure; And It is formed to be bonded to the fixed part of the first substrate and spaced apart from the movable structure by a predetermined distance, and to move by applying an electric force to the signal transmission line and the movable structure for transmitting a signal by contacting and non-contact with the contact portion. A second substrate including a fixed electrode; The movable structure includes a moving electrode corresponding to the fixed electrode, wherein the moving electrode has an air resistance blocking hole and is connected to a plurality of elastic members. delete 15. The fine driver as claimed in claim 14, wherein each of the elastic members has a curved structure. 15. The fine driver as claimed in claim 14, wherein the first substrate and the second substrate are made of single crystal silicon and glass, respectively. 18. The fine driver as claimed in claim 17, wherein the contact portion formed on the first substrate and the fixed electrode formed on the second substrate and the signal transmission line are made of metal. 18. The fine driver as claimed in claim 17, wherein the movable electrode and the elastic member formed on the first substrate are made of single crystal silicon. 15. The micro driver of claim 14, wherein the movable structure of the first substrate is formed to be driven out of the plane perpendicular to the substrate. 15. The micro driver as claimed in claim 14, wherein the movable structure of the first substrate is formed to be driven in an in-plane direction parallel to the substrate. 15. The micro driver of claim 14, wherein the movable structure of the first substrate is formed to be driven in an in-plane direction parallel to the substrate and in an out-plane direction perpendicular to the substrate. 21. The micro driver as claimed in claim 20, which is an RF switch.

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