TWI697747B - Control method and testing method for micro-electro-mechanical systems device - Google Patents

Abstract

A control method for MEMS device is provided. The MEMS device includes a first electrode and a second electrode. The control method includes the following operations. A starting signal is provided. The starting signal has a ramp-up stage and a ramp-down stage. The ramp-up stage is applied to the MEMS device to move the first electrode to form a power on state with the second electrode. The ramp-down stage is applied to the MEMS device. The first electrode and the second electrode are maintained at the power on state. A shutdown signal is provided. The shutdown signal is applied to the MEMS device to change the first electrode and the second electrode from the power on state to the shutdown state. A testing method for MEMS device is also provided.

Description

Control method and test method of MEMS device

This disclosure relates to a micro-electro-mechanical system device, in particular to a control method and a test method of the micro-electro-mechanical system device.

For many modern applications, electronic equipment involving semiconductor devices is very important. Technological advances in materials and design have produced generations of semiconductor devices, each with smaller and more complex circuits than the previous generation. In the process of progress and innovation, it is common to increase the functional design (that is, the number of interconnected devices per chip area) and reduce the geometric size (that is, the smallest component that can be produced using a manufacturing process). This progress has increased the complexity of processing and manufacturing semiconductor devices. Recently, micro-electro mechanical system (MEMS) devices have been developed, and they are also generally related to electronic equipment. MEMS devices are micro-sized devices, usually in the range of less than 1 micron to several millimeters. MEMS devices include manufacturing using semiconductor materials to form mechanical and electrical features. The MEMS device may include some elements (such as static or movable elements) to achieve motor functionality. MEMS devices are widely used in various applications. MEMS applications include motion sensors, pressure sensors, printing nozzles, or the like. Other MEMD applications include inertial sensors, such as accelerometers for measuring linear acceleration, and gyroscopes for measuring angular velocity. Furthermore, MEMS applications extend to optical applications, such as movable mirrors, and radio frequency (RF) applications, such as RF switches or the like.

An embodiment of the present disclosure relates to a control method of a micro-electro-mechanical system device, the micro-electro-mechanical system device includes a first electrode and a second electrode, the method includes: providing a turn-on signal, wherein the turn-on signal has a rising area Section and a descending section; applying the ascending section to the MEMS device, so that the first electrode moves to form an open state with the second electrode; applying the descending section to the MEMS device, the first An electrode and the second electrode are maintained in the open state; an off signal is provided; the off signal is applied to the microelectromechanical system device, so that the first electrode and the second electrode change from the open state to an off state.

Another embodiment of the present disclosure relates to a method for controlling a MEMS device. The MEMS device includes a first electrode and a second electrode. The method includes: applying a positive current at a first time interval, Move the first electrode to form an open state with the second electrode; apply a negative current at a second time interval to maintain the first electrode and the second electrode in the open state; a third time At intervals, an off signal is applied to make the first electrode and the second electrode change from the open state to a closed state.

Another embodiment of the present disclosure relates to a method for testing a MEMS device. The method includes: providing the MEMS device, which includes a first electrode and a second electrode; and applying a A positive current is applied to the MEMS device to move the first electrode to form an open state with the second electrode; a negative current is applied to the MEMS device at a second time interval to make the first electrode and The second electrode is maintained in the open state; in a third time interval, an off signal is applied to the MEMS device, so that the first electrode and the second electrode change from the open state to an off state.

The following disclosure provides many different embodiments or examples for implementing different features of the provided subject matter. Specific examples of components and configurations are described below to simplify the disclosure. These are only examples and are not intended to be limiting. For example, in the following description, a first member formed on or on a second member may include an embodiment in which the first member and the second member are formed in direct contact, and may also include an additional member formed on the first member. An embodiment in which the first member and the second member may not be in direct contact between the member and the second member. In addition, the present disclosure may repeat element symbols and/or letters in various examples. This repetition is for the purpose of simplicity and clarity, and does not itself specify one of the relationships between the various embodiments and/or configurations discussed.

The embodiments of the present disclosure are discussed in detail below. However, it should be understood that this disclosure provides many applicable inventive concepts that can be embodied in a variety of specific background content. The specific embodiments discussed are only illustrative and do not limit the scope of this disclosure.

In addition, for ease of description, spatially relative terms (such as "bottom", "below", "down", "above", "up", "down", "left", "right" and the like can be used in this text ) To describe the relationship between one element or component and another element or component(s), as shown in the figure. In addition to the orientations depicted in the figures, spatially relative terms are also intended to cover different orientations of the device in use or operation. The device can be oriented in other ways (rotated by 90 degrees or in other orientations), and therefore the spatial relative descriptors used in this article can also be interpreted. It will be understood that when an element is referred to as being “connected to” or “coupled to” another element, it can be directly connected or coupled to the other element, or intervening elements may be present.

Since micro-electro mechanical system (MEMS) devices are widely used in various applications, it is usually necessary for a MEMS device structure to accommodate more than one form of MEMS function. For example, a single MEMS architecture can include an accelerometer and a gyroscope. Regarding these MEMS devices, the final product is manufactured into a composite wafer and performs functions with reduced grain size.

On the other hand, one of the reliability problems observed in MEMS devices is stiction or adhesion of contact surfaces due to surface forces. Generally speaking, adhesion is the static friction that needs to be overcome in order to enable the stationary objects in contact with each other to move together. For example, in a MEMS device, when two surfaces with an area below the millimeter range are close, the two surfaces will stick together, which limits the reliability of the MEMS device. In terms of this size, the main cause of failure of MEMS devices is electrostatic or adhesion caused by charges.

The present disclosure provides a MEMS device control method and test method that can alleviate the above-mentioned problems. 1 and 2 are schematic diagrams of a MEMS device 100 according to some embodiments. The MEMS device 100 includes a first electrode 102 and a second electrode 104. In some embodiments, the MEMS device 100 may further include a first substrate 101, a second substrate 103 and a dielectric layer 105. The first electrode 102 is connected to the first substrate 101, the second electrode 104 is connected to the second substrate 103, and the dielectric layer 105 is disposed on the second electrode 104. It should be noted that, for clarity, FIG. 1 simply shows a part of the structure of the MEMS device 100. For example, the first substrate 101 only shows the part connected to the first electrode 102, and the structure shown in the figure is not intended to limit the disclosure.

The first substrate 101 and/or the second substrate 103 includes a semiconductor material, such as silicon. In some embodiments, the first substrate 101 and/or the second substrate 103 may include other semiconductor materials, such as silicon germanium, silicon carbide, gallium arsenide, or the like. In some embodiments, the first substrate 101 and/or the second substrate 103 is a p-type semiconductor substrate (acceptor type) or an n-type semiconductor substrate (supplier type). Alternatively, the first substrate 101 and/or the second substrate 103 includes another elemental semiconductor, such as germanium; compound semiconductors, including silicon carbide, gallium arsenide, gallium phosphide, indium phosphide, indium arsenide, and/or antimony Indium; alloy semiconductor, including SiGe, GaAsP, AlInAs, AlGaAs, GaInAs, GaInP and/or GaInAsP; or a combination thereof. Alternatively, the first substrate 101 and/or the second substrate 103 are semiconductor-on-insulators. In some embodiments, the material of the first substrate 101 may be the same as the material of the second substrate 103.

In some embodiments, the first substrate 101 may be bonded to the second substrate 103. In some embodiments, the first substrate 101 is a MEMS substrate, and the second substrate 103 is a carrier wafer. The first substrate 101 and the second substrate 103 that are joined together include a movable MEMS area, which is an area of the first substrate 101 and the second substrate 103, and the movable feature or part of the MEMS structure is formed on this area. The structure of an electrode 102 and a second electrode 104.

The first electrode 102 is a movable electrode. In some embodiments, the first electrode 102 may be formed of a conductive or semiconductor material, and the first electrode 102 may include polysilicon. In some embodiments, the first electrode 102 is conductive and capacitive. In some embodiments, the first electrode 102 is a movable or vibrable element. In other embodiments, the first electrode 102 is a movable membrane or diaphragm. In some embodiments, the first electrode 102 is formed in the first substrate 101. For example, a plasma etching process can be used to etch the first substrate 101 to form the first electrode 102.

The second electrode 104 may be formed of a conductor. Alternatively, the second electrode 104 may be formed of a semiconductor material. In some embodiments, the second electrode 104 may include metal, such as gold, silver, aluminum, titanium, copper, tungsten, nickel, titanium, chromium, and alloys, oxides, or nitrides thereof.

In some embodiments, the displacement of the first electrode 102 relative to the second electrode 104 will cause the capacitance between the first electrode 102 and the second electrode 104 to change. In some embodiments, the first electrode 102 is configured to capture impedance changes caused by gas movement in the groove between it and the first substrate 101. Then, the capacitance or impedance change is translated into an electronic signal by the circuit connected to the first electrode 102 or the second electrode 104. In some embodiments, the generated electronic signal is transmitted to another device, another substrate, or another circuit for further processing.

The dielectric layer 105 contains silicon, or its oxide. Alternatively, the dielectric layer 105 contains silicon nitride. In some embodiments, the dielectric layer 105 includes a dielectric material, such as oxide (such as Ge oxide), oxynitride (such as GaP oxynitride), silicon dioxide (SiO ₂ ), oxynitride (nitrogen-bearing oxide) (for example, nitrogen-bearing SiO2), nitrogen-doped oxide (for example, N ₂ implanted SiO ₂ ), silicon oxynitride (Si _x O _y N _z ), and the like.

In some embodiments, in response to the control signal, the movable first electrode 102 and the second electrode 104 are close to each other (as shown in FIG. 2), and the first electrode 102 returns to its original structure (as shown in FIG. 1). Show). In some embodiments, after the first electrode 102 and the second electrode 104 are close to each other, the first electrode 102 may be attached to the dielectric layer 105 and remain stationary for a period of time.

In some existing control methods, during the static period of the first electrode 102, since the control signal is a signal of a constant voltage, charges will be injected from the first electrode 102 into the dielectric layer 105, thereby causing adhesion problems. In order to solve the above-mentioned problems, in some embodiments of the present disclosure, a control method of a MEMS device is provided.

FIG. 3 is a schematic diagram of a control signal sequence 200 of a MEMS device according to some embodiments. The control signal sequence 200 has an opening signal 300 and a closing signal 400. In some embodiments, the turn-on signal 300 has a rising section 302 and a falling section 304. The rising section 302 and the falling section 304 are alternately generated, for example, and the number of the rising section 302 and the falling section 304 is not limited.

In some embodiments, the rising section 302 is, for example, a positive current. In the first time interval T1, applying the rising section 302 to the MEMS device 100 causes the first electrode 102 to move to form an open state with the second electrode 104 (as shown in FIG. 2 shown). Here, the open state means that the first electrode 102 and the second electrode 104 are close to each other to the first position to form an electrical connection. In some embodiments, the movable first electrode 102 is attached to the dielectric layer 105 and is close to the second electrode 104 to form an electrical connection. Since the first electrode 102 and the second electrode 104 are electrically connected, the first electrode 102 and the second electrode 104 are in an open state.

In some embodiments, the falling section 304 is, for example, a negative current, and the falling section 304 is applied to the MEMS device 100 during the second time interval T2. Since the electrostatic force between the first electrode 102 and the second electrode 104 is proportional to the square of the voltage, in the case of a fixed resistance, the voltage will also be proportional to the current, so the first electrode 102 and the second electrode 104 The electrostatic force between them will also be proportional to the square of the current. In other words, even if the falling section 304 has a negative current, the first electrode 102 and the second electrode 104 will still approach each other to form an electrical connection. Therefore, the first electrode 102 is still attached to the dielectric layer 105 and is electrically connected to the second electrode 104 to maintain the on state.

It is worth mentioning that the number of ascending sections 302 and descending sections 304 is not limited. For example, in this embodiment, three ascending sections 302 and three descending sections 304 are used for illustration, but they are not limiting. . Among them, the positive current (rising section 302) and negative current (falling section 304) can be generated sequentially. In other words, a negative current is generated after a positive current, and a positive current is generated after a negative current.

Therefore, by adjusting the positive and negative flow direction of the current in the turn-on signal 300, it is possible to avoid the problem of adhesion caused by the signal of a fixed voltage that will cause charges to be injected from the first electrode 102 into the dielectric layer 105.

In some embodiments, after the turn-on signal 300, the turn-off signal 400 may be provided. In the third time interval T3, the turn-off signal 400 is applied to the MEMS device 100, which causes the first electrode 102 and the second electrode 104 to change from the on state to the off state (as shown in FIG. 1). Here, the closed state means that the first electrode 102 and the second electrode 104 are far away from each other to a second position to form an electrical disconnection. In some embodiments, the movable first electrode 102 is far away from the dielectric layer 105 and is electrically disconnected from the second electrode 104. In other words, the first electrode 102 will return to its original straight structure.

As mentioned above, by modulating the positive and negative flow direction of the current in the turn-on signal 300, for example, using an alternating current signal, the injection of charges from the first electrode 102 into the dielectric layer 105 can be reduced, thereby reducing adhesion problems. Furthermore, the time interval between the rising section 302 and the falling section 304 in the turn-on signal 300 (for example, the first time interval T1 or the second time interval T2) is less than the time interval required for the first electrode 102 to return to the original state (for example , The third time interval T3), therefore, the modulation in the turn-on signal 300 does not cause the first electrode 102 and the second electrode 104 to change from the on state to the off state. In other words, the electrical delay of the modulation in the turn-on signal 300 is less than the mechanical delay of the first electrode 102 changing state, so the modulation in the turn-on signal 300 will not control the MEMS device This has an impact and can alleviate the problem of adhesion between the first electrode 102 and the second electrode 104.

4 and 5 are schematic diagrams of a MEMS device 400 according to other embodiments. The MEMS device 400 includes a first electrode 402 and a second electrode 404. The difference between the MEMS device 400 and the MEMS device 100 of FIGS. 1 and 2 is that the MEMS device 400 includes a first substrate 401 and a second substrate 403, but does not include a dielectric layer. A gap 405 is formed between the first electrode 402 and the second electrode 404, for example. The composition of the first electrode 402, the second electrode 404, the first substrate 401, and the second substrate 403 has been described in detail in FIGS. 1 and 2 and will not be repeated here.

As described above, in response to the control signal, the movable first electrode 402 and the second electrode 404 will approach each other to the first position (as shown in FIG. 5), and the first electrode 402 will return to its original structure (as shown in FIG. 4). Shown). In some embodiments, after the first electrode 402 and the second electrode 404 approach each other, there is still a gap 405 between the first electrode 402 and the second electrode 404, and the first electrode 402 may be stationary for a period of time.

In some existing control methods, during the static period of the first electrode 402, since the control signal is a signal of a fixed voltage, the charge will dissociate and generate electrostatic force, which will cause adhesion problems. Therefore, the embodiment shown in FIG. 3 can also solve the above-mentioned problems.

As described above in FIG. 3, by modulating the positive and negative flow direction of the current in the turn-on signal 300, it is possible to avoid the problem of adhesion caused by the signal of a fixed voltage causing the charge to dissociate from the first electrode 402.

As mentioned above, by modulating the positive and negative flow direction of the current in the turn-on signal 300, such as using an alternating current signal, the electrostatic force generated by the dissociation of the charge from the first electrode 402 can be reduced, thereby reducing the problem of adhesion. Furthermore, the time interval between the rising section 302 and the falling section 304 in the turn-on signal 300 (for example, the first time interval T1 or the second time interval T2) is less than the time interval required for the first electrode 402 to return to the original state (for example , The third time interval T3), so the modulation in the turn-on signal 300 does not cause the first electrode 402 and the second electrode 404 to change from the on state to the off state. In other words, the electrical delay of the modulation in the turn-on signal 300 is smaller than the mechanical delay of the first electrode 402 changing state. Therefore, the modulation in the turn-on signal 300 does not affect the control of the MEMS device, and can reduce the first electrode 402. The problem of adhesion to the second electrode 404.

FIG. 6 shows a flowchart of a control method 600 of a MEMS device according to some embodiments of the disclosure. As shown in FIG. 6, the control method 600 has an operation 602, an operation 604, an operation 606, and an operation 610. Operation 602 provides an opening signal, wherein the opening signal has a rising section and a falling section. Operation 604 is to apply the rising section to the MEMS device to move the first electrode to form an open state with the second electrode. Operation 606 is to apply the descending section to the MEMS device, and the first electrode and the second electrode are maintained in an on state. Operation 608 provides a shutdown signal. Operation 610 is to apply an off signal to the MEMS device, so that the first electrode and the second electrode change from an open state to a closed state. Since the control method 600 of the MEMS device has been described in detail in FIGS. 1, 2, 3, 4, and 5, it will not be repeated here. It should be noted that this embodiment can add additional operations before, during, and after the method 600.

FIG. 7 shows a flowchart of a control method 700 of a MEMS device according to other embodiments of the present disclosure. As shown in FIG. 7, the control method 700 has an operation 702, an operation 704, and an operation 706. Operation 702 is to apply a positive current at a first time interval to move the first electrode to form an open state with the second electrode. Operation 704 is to apply a negative current at a second time interval to maintain the first electrode and the second electrode in the on state. Operation 706 is to apply an off signal at a third time interval to change the first electrode and the second electrode from an on state to an off state. Since the control method 700 of the MEMS device has been described in detail in FIGS. 1, 2, 3, 4, and 5, it will not be repeated here. It should be noted that this embodiment can add additional operations before, during, and after the method 700.

FIG. 8 is a flowchart of a method 800 for testing a MEMS device according to some embodiments of the disclosure. As shown in FIG. 8, the testing method 800 has operations 802, 804, 806, and 810. Operation 802 is to provide a MEMS device, which includes a first electrode and a second electrode. Operation 804 is to apply a positive current at a first time interval to move the first electrode to form an open state with the second electrode. Operation 806 is to apply a negative current at a second time interval to maintain the first electrode and the second electrode in the on state. Operation 808 is to apply an off signal at a third time interval to change the first electrode and the second electrode from an on state to an off state. The MEMS device testing method 800 can test the MEMS device in a manner similar to the above-mentioned control methods 600 and 700 to determine whether the first electrode and the second electrode have adhesion problems. Since the control methods 600 and 700 have been described in detail in FIGS. 1, 2, 3, 4, and 5, they will not be repeated here. It should be noted that this embodiment can add additional operations before, during, and after the method 800.

In summary, by modulating the positive and negative current flow in the turn-on signal, such as using an AC signal, the charge injected from the first electrode into the dielectric layer or the electrostatic force generated by the first electrode can be reduced, thereby reducing adhesion problems . Furthermore, the time interval between the rising section and the falling section in the turn-on signal (for example, the first time interval or the second time interval) is less than the time interval required for the first electrode to return to the original state (for example, the third time interval) Therefore, the modulation in the turn-on signal does not cause the first electrode and the second electrode to change from the on state to the off state. In other words, the electrical delay of the modulation in the turn-on signal is less than the mechanical delay of the first electrode changing state, so the modulation in the turn-on signal will not affect the control of the MEMS device, and can reduce the first electrode and the second electrode The problem of adhesion. Furthermore, during the testing phase, it is also possible to determine whether the first electrode and the second electrode have adhesion problems.

In some embodiments, a method for controlling a MEMS device is provided. The MEMS device includes a first electrode and a second electrode, and the control method includes the following operations. An opening signal is provided, wherein the opening signal has a rising section and a falling section. Applying the rising section to the MEMS device to move the first electrode to form an open state with the second electrode. The descending section is applied to the MEMS device, and the first electrode and the second electrode are maintained in an on state. Provide a close signal. The off signal is applied to the micro-electromechanical system device to make the first electrode and the second electrode change from an open state to a closed state.

In some other embodiments, a method for controlling a MEMS device is provided. The MEMS device includes a first electrode and a second electrode, and the control method includes the following operations. In a first time interval, a positive current is applied to move the first electrode to form an open state with the second electrode. In a second time interval, a negative current is applied to maintain the first electrode and the second electrode in an on state. In a third time interval, an off signal is applied to make the first electrode and the second electrode change from an on state to an off state.

In some other embodiments, a method for testing a MEMS device is provided. The test method includes the following operations. A MEMS device is provided, which includes a first electrode and a second electrode. In a first time interval, a positive current is applied to the MEMS device to move the first electrode to form an open state with the second electrode. During a second time interval, a negative current is applied to the MEMS device to maintain the first electrode and the second electrode in an on state. In a third time interval, an off signal is applied to the MEMS device, so that the first electrode and the second electrode change from an on state to an off state.

The features of several embodiments are summarized above, so that those familiar with the art can better understand the aspect of the disclosure. Those familiar with the technology should understand that they can easily use the present disclosure as a basis for designing or modifying other programs and structures to perform the same purpose and/or achieve the same advantages of the embodiments described herein. Those familiar with the technology should also realize that these equivalent structures do not depart from the spirit and scope of this disclosure, and various changes, substitutions and alterations can be made in this article without departing from the spirit and scope of this disclosure.

100, 400: MEMS device

101, 401: first substrate

102, 402: first electrode

103, 403: second substrate

104, 404: second electrode

105: Dielectric layer

200: Control signal sequence

300: Turn on the signal

302: Ascending section

304: descending section

400: Turn off the signal

T1: the first time interval

T2: second time interval

T3: third time interval

600, 700: control method

602, 604, 606, 608, 610, 702, 704, 706, 802, 804, 806, 808: Operation

800: test method

When reading in conjunction with the drawings, the aspect of this disclosure is best understood from the following [Embodiments]. It should be noted that according to standard practice in the industry, various components are not drawn to scale. In fact, for clear discussion, the size of each component can be increased or decreased arbitrarily. 1 and 2 are schematic diagrams of MEMS devices according to some embodiments. FIG. 3 is a schematic diagram of a control signal sequence of a MEMS device according to some embodiments. 4 and 5 are schematic diagrams of MEMS devices according to other embodiments. FIG. 6 is a flowchart showing a control method of a MEMS device according to some embodiments of the disclosure. FIG. 7 shows a flowchart of a control method of a MEMS device according to other embodiments of the disclosure. FIG. 8 shows a flowchart of a testing method of a MEMS device according to some embodiments of the disclosure.

600: control method

602, 604, 606, 608, 610: Operation

Claims (10)

A control method of a microelectromechanical system device, the microelectromechanical system device comprising a first electrode and a second electrode, the method comprising: providing an ON signal, wherein the ON signal has a rising section and a falling section Section; applying the rising section to the MEMS device, so that the first electrode moves to form an open state with the second electrode; applying the falling section to the MEMS device, the first electrode and the first electrode The two electrodes are maintained in the open state; an OFF signal is provided; and the close signal is applied to the MEMS device, so that the first electrode and the second electrode change from the open state to an off state. The control method according to claim 1, wherein the electrical delay of the turn-on signal from the rising section to the falling section is less than the change of the first electrode from the on state to the off state The mechanical delay (mechanical delay). The control method according to claim 2, wherein the turn-on signal includes a plurality of rising sections and a plurality of falling sections, and the rising sections and the falling sections are generated alternately. The control method according to claim 1, wherein a time interval of the rising section or the falling section is smaller than a time interval of the closing signal. A method for controlling a micro-electro-mechanical system device, the micro-electro-mechanical system device includes a first electrode and a second electrode. The method includes: applying a positive current at a first time interval to move the first electrode to The second electrode forms an ON state; in a second time interval, a negative current is applied to maintain the first electrode and the second electrode in the ON state; and in a third time interval, an off state is applied The signal causes the first electrode and the second electrode to change from the open state to an OFF state. The control method according to claim 5, wherein the electrical delay of the turn-on signal from the positive current to the negative current is less than the mechanical delay of the first electrode changing from the on state to the off state Mechanical delay. The control method according to claim 6, wherein the positive current and the negative current are generated sequentially. The control method according to claim 5, wherein the first time interval or the second time interval is smaller than the third time interval. A method for testing a microelectromechanical system device, the method comprising: providing the microelectromechanical system device, which includes a first electrode and a second electrode; applying a positive current to the microelectromechanical system device at a first time interval, Moving the first electrode to form an ON state with the second electrode; In a second time interval, a negative current is applied to the MEMS device to maintain the first electrode and the second electrode in the on state; in a third time interval, an off signal is applied to the MEMS device The device causes the first electrode and the second electrode to change from the open state to an OFF state. The test method according to claim 9, further comprising: judging whether the first electrode and the second electrode have stiction.

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