CN104876176A - Movable inductive electrode structure and production method - Google Patents

Abstract

The present invention relates to a movable inductive electrode structure and a preparation method. The movable inductive electrode structure includes: an upper plate and a lower plate that are separated from each other up and down, and are used to form two electrode plates of a variable capacitance in MEMS. Wherein, both the upper pole plate and the lower pole plate are planar spiral inductors, so that the upper pole plate and the lower pole plate move with each other when electrified. On the one hand, the electrode structure of the present invention can measure the capacitance of the two pole plates to calculate the distance between the pole plates like ordinary capacitance, which can be converted into acceleration for the acceleration sensor. On the other hand, it is also possible to measure the magnetic induction current caused by the proximity of the pole plates, that is, the speed at which the distance between the capacitive pole plates changes, and measure the change speed of the motion acceleration through conversion.

Description

A movable inductance electrode structure and preparation method

technical field

The invention relates to the field of semiconductors, and in particular, the invention relates to a movable inductance electrode structure and a preparation method.

Background technique

With the continuous development of semiconductor technology, in the market of sensor (motion sensor) products, smart phones, integrated CMOS and microelectromechanical system (MEMS) devices are increasingly becoming the most mainstream and advanced technology, and with the update of technology , the development direction of this type of transmission sensor products is smaller size, high-quality electrical performance and lower loss.

Micro-electro-mechanical systems (MEMS) have obvious advantages in terms of volume, power consumption, weight, and price. So far, many different sensors have been developed, such as pressure sensors, acceleration sensors, inertial sensors, and other sensors.

In the prior art, in the MEMS device, the acceleration of the upper plate and the lower plate is sensed by the sensing space to generate a displacement, thereby causing a change in the capacitance of the sensor. In order to prevent interference with the For the displacement test and capacitance change, the X-axis, Y-axis and Z-axis are not integrated in MEMS devices, but the X-axis, Y-axis and Z-axis are separately set on the same crystal circle on.

The MEMS device as shown in Figure 1a includes an acceleration sensor 10 and a pressure sensor 11, two parts, wherein the acceleration sensor 10 includes a movable part 101, and the pressure sensor 11 includes a pressure sensing film 102, as shown in Figure 1b As shown, when the device is working, by applying a direct current voltage (VDC) and an alternating current voltage (AC) to the upper plate 104 and the lower plate 105, the pressure sensing film 102 above the cavity 103 in the pressure sensor 11 is electrostatically Vibrates, emits ultrasonic waves. When the ultrasonic wave receives the ultrasonic pressure, the pressure sensing membrane 102 vibrates, causing the capacitance between the two electrodes to change, as shown in Figure 2, which is the variable capacitance electrode plate in the MEMS device described in the prior art Schematic.

The traditional MEMS inductor design mainly considers the high quality factor (Q value), which is a radio frequency tunable micro-inductor. Radio frequency tunable micro-inductors play an important role today, which can meet the requirements of high-performance compact device design. For device designers, adjustable inductors can tune the inductance and ensure a high or appropriate quality factor (Q value).

Most of MEMS devices can be regarded as the design of variable capacitors, such as measuring the capacitance change by using the distance or area change between the two plates of the capacitor, or using the electrostatic force of the two plates to make the plates attract each other. Specifically, pressure sensors, acceleration sensors, etc. all use such a design. However, there is often a gap between the capacitor plates. After the two plates are close, they cannot be separated by the electrostatic force of the plates. Only a spring structure can be designed to reset the capacitor plates, resulting in a complex structure and a reduced integration. Therefore, in order to further improve the performance of the device, it is necessary to improve the electrode plate of the MEMS in the prior art.

Contents of the invention

A series of concepts in simplified form are introduced in the Summary of the Invention, which will be further detailed in the Detailed Description. The summary of the invention in the present invention does not mean to limit the key features and essential technical features of the claimed technical solution, nor does it mean to try to determine the protection scope of the claimed technical solution.

In order to overcome the current existing problems, the present invention provides a MEMS movable inductive electrode structure, including:

The upper pole plate and the lower pole plate which are arranged up and down are used to form the two electrode plates of the variable capacitor in MEMS, wherein the upper pole plate and the lower pole plate are both selected planar spiral inductors, so that the upper pole The plates and said lower plate move relative to each other when energized.

Preferably, the planar spiral inductor is a square spiral inductor or a circular spiral inductor.

Preferably, the movable inductive electrode structure further includes an independent inductive core, and the inductive core is located at the center of the planar spiral inductor.

Preferably, the inductor core is an inductor wire.

Preferably, the movable inductive electrode structure further includes an upper plane plate and a lower plane plate, the upper plane plate and the lower plane plate are set as a whole, and the upper pole plate and the lower pole plate are respectively embedded in the the upper plane plate and the lower plane plate.

Preferably, the upper plate and the lower plate include two or more identical planar spiral inductors.

Preferably, when the first connection end of the upper pole plate is electrically connected to the corresponding first connection end of the lower pole plate, it is used to measure the distance between the upper pole plate and the lower pole plate.

As a preference, when the first connection end and the second connection end of the upper pole plate are electrically connected, and the first connection end and the second connection end of the lower pole plate are electrically connected at the same time, the upper pole plate and the lower pole plate Mutual motion occurs between the plates.

Preferably, when the inductor current in the upper pole plate and the lower pole plate are the same, the upper pole plate and the lower pole plate attract each other;

When the inductor currents in the upper pole plate and the lower pole plate are opposite, the upper pole plate and the lower pole plate repel each other.

Preferably, the first connection end and the second connection end of the lower pole plate are electrically connected to measure the induced current of the reaction distance change speed in the first connection end and the second connection end of the upper pole plate.

The present invention also provides a method for preparing a MEMS movable inductive electrode structure, comprising:

A semiconductor substrate is provided, on which a lower pole plate is formed, and the lower pole plate is a planar spiral inductor;

forming a sacrificial material layer on the lower plate;

forming an upper pole plate on the sacrificial material layer, and the upper pole plate is a planar spiral inductor;

The sacrificial material layer is removed to form a cavity between the upper plate and the lower plate.

Preferably, the method includes:

A semiconductor substrate is provided, on which a lower plane plate and a lower pole plate are formed, and the lower pole plate is embedded in the lower plane plate;

depositing a layer of sacrificial material on the lower plane plate and the lower plate;

forming an upper planar plate material layer on the sacrificial material layer;

forming an upper plate material layer on the upper plane plate material layer;

patterning the upper plate material layer to form the upper plate of a planar spiral inductor;

patterning the upper plane material layer and the upper plate to form openings exposing the sacrificial material layer;

The layer of sacrificial material is removed.

Preferably, the method further includes patterning the sacrificial material layer after depositing the sacrificial material layer on the lower plane plate and the lower electrode plate, so as to remove part of the sacrificial material layer on one end to expose the lower plane plate. panel;

and patterning the upper plane material layer and the upper plate to form an opening to expose the unetched end of the sacrificial material layer.

Preferably, the method further includes continuing to deposit the upper plate material layer after forming the upper plate, so as to form an upper plate covering the upper plate.

Preferably, the method further includes, after depositing a sacrificial material layer on the lower plane plate and the lower pole plate, patterning the sacrificial material layer to form openings at both ends to expose the lower capacitor substrate, and at the same time A groove is formed in the middle of the sacrificial material layer;

forming an upper plane plate material layer and an upper pole plate material layer in the groove;

patterning the capacitive plate material layer and the upper plate material layer to form the upper plate of the planar spiral inductor;

Continuing to deposit layers of upper plate material to form an upper plate covering the upper plate.

In order to solve the problems existing in the prior art, the present invention provides a new MEMS movable inductance electrode structure. The electrode structure adopts a new capacitor plate structure, and the inductance is introduced into the design of the movable capacitor plate. In this state, the two inductances can move with each other, adding the same current direction to the inductance on the two polar plates will generate a magnetic field in the same direction and the two polar plates will attract each other. At the same time, it is also possible to apply an anti-phase current to push away the two polar plates. Therefore, the problem in the prior art that the two pole plates cannot be separated by the electrostatic force of the pole plates is solved.

On the one hand, the electrode structure of the present invention can measure the capacitance of the two pole plates to calculate the distance between the pole plates like ordinary capacitance, which can be converted into acceleration for the acceleration sensor. On the other hand, it is also possible to measure the magnetic induction current caused by the proximity of the pole plates, that is, the speed at which the distance between the capacitive pole plates changes, and measure the change speed of the motion acceleration through conversion.

Description of drawings

The following drawings of the invention are hereby included as part of the invention for understanding the invention. Embodiments of the present invention and their descriptions are shown in the drawings to explain the device and principle of the present invention. In the attached picture,

Figures 1a-1b are schematic structural views of MEMS devices described in the prior art;

Fig. 2 is the structural representation of the variable capacitance electrode plate in the MEMS device described in the prior art;

3a-3e are structural schematic diagrams of variable capacitance electrode plates in MEMS devices described in the prior art;

4a-4h are schematic diagrams of the MEMS device and the manufacturing process described in a specific embodiment of the present invention;

5a-5e are schematic diagrams of the preparation process of the MEMS device described in another specific embodiment of the present invention;

6a-6f are schematic diagrams of the MEMS device and its preparation process described in another specific embodiment of the present invention;

Fig. 7 is a flow chart of the fabrication process of the MEMS device in another specific embodiment of the present invention.

Detailed ways

In the following description, numerous specific details are given in order to provide a more thorough understanding of the present invention. It will be apparent, however, to one skilled in the art that the present invention may be practiced without one or more of these details. In other examples, some technical features known in the art are not described in order to avoid confusion with the present invention.

In order to thoroughly understand the present invention, a detailed description will be provided in the following description to illustrate the method for fabricating the single-chip MEMS of the present invention. Obviously, the practice of the invention is not limited to specific details familiar to those skilled in the semiconductor arts. Preferred embodiments of the present invention are described in detail below, however, the present invention may have other embodiments besides these detailed descriptions.

It should be noted that the terms used herein are for the purpose of describing specific embodiments only, and are not intended to limit exemplary embodiments according to the present invention. As used herein, singular forms are intended to include plural forms unless the context clearly dictates otherwise. In addition, it should also be understood that when the terms "comprising" and/or "comprising" are used in this specification, it indicates the presence of the features, integers, steps, operations, elements and/or components, but does not exclude the presence or One or more other features, integers, steps, operations, elements, components and/or combinations thereof are added.

Now, exemplary embodiments according to the present invention will be described in more detail with reference to the accompanying drawings. These example embodiments may, however, be embodied in many different forms and should not be construed as limited to only the embodiments set forth herein. It should be understood that these embodiments are provided so that this disclosure will be thorough and complete and will fully convey the concept of these exemplary embodiments to those of ordinary skill in the art. In the drawings, the thicknesses of layers and regions are exaggerated for clarity, and the same reference numerals are used to designate the same elements, and thus their descriptions will be omitted.

In order to solve the problems existing in the prior art, the present invention provides a new MEMS movable inductance electrode structure. The electrode structure adopts a new capacitor plate structure, and the inductance is introduced into the design of the movable capacitor plate. In this state, the two inductances can move with each other, adding the same current direction to the inductance on the two polar plates will generate a magnetic field in the same direction and the two polar plates will attract each other. At the same time, it is also possible to apply an anti-phase current to push away the two polar plates. Therefore, the problem in the prior art that the two pole plates cannot be separated by the electrostatic force of the pole plates is solved.

The structure of the present invention will be further described below in conjunction with the accompanying drawings.

Example 1

The electrode structure will be further described below in conjunction with FIGS. 3a-3e, wherein 3a-3e are top views of the electrode plate, and the figure on the right side of 3a is a side view of the electrode structure.

In order to solve the problems existing in the prior art, the present invention changes the ordinary entire capacitor plate in the prior art as a variable electrode plate in the MEMS device, and turns the entire plate of the MEMS movable capacitor into a ring winding designed to form an inductor.

Specifically, in the MEMS variable capacitor, both the upper plate 204 and the lower plate 202 use planar spiral inductors as the two electrode plates of the variable capacitor in the MEMS, so that the upper plate and the lower plate Mutual motion under energization.

Wherein, the shape of the spiral inductor can be a square coil, as shown in the figure on the left side of Fig. 3a, or it can be a circular coil, as shown in Fig. 3c. In addition, other inductors other than square and round can be selected. picture of. It is not limited to the above two examples, and other shapes such as triangle or polygon can also be selected.

As a preference, an inductance core can also be arranged between the upper plate and the lower plate of the spiral inductor, wherein the inductor core is set at the center of the spiral inductor, as shown in Figure 3b, it is located at the center of the spiral inductor The center of the spiral inductor is set independently and isolated from the spiral inductor; the inductor core is preferably a piece of wire having the same material as the spiral inductor, but it is not limited to this example.

As a preference, there is a cavity between the upper pole plate 204 and the lower pole plate 202 of the MEMS variable capacitor, and the air in the cavity is used as the dielectric of the variable capacitor. As a preference, the upper pole Plate 204 and lower plate 202 use the same spiral inductor.

Further, the MEMS variable capacitor electrode plate structure further includes an upper plane plate and a lower plane plate, and the upper plane plate and the lower plane plate are set as a whole, and the common whole capacitor plate in the prior art can be selected, wherein The upper pole plate and the lower pole plate are respectively embedded in the upper plane plate and the lower plane plate.

Wherein the function of the capacitor plate and the lower plane plate is different from that of the electrode plate in the prior art. In the present invention, the capacitor plate and the lower plane plate play a role in fixing and supporting the upper The function of the polar plate 204 and the lower plate 202 is that the capacitor plate and the lower plane plate are not energized, so conductive materials or non-conductive materials can be selected.

The spiral inductor can be connected to electricity at both ends or at one end. When the upper plate (spiral inductor) and the lower plate are connected to electricity at one end, its function is the same as that of the capacitor plate electrode in the prior art, which is equivalent to Ordinary capacitor plates can measure the capacitance of the two plates to calculate the distance between the plates like ordinary capacitors. For acceleration sensors, it can be converted into acceleration.

When both ends of the inductance of the two polar plates are connected with electricity, electromagnetic induction can be used to make the two polar plates attract or repel each other. It is also possible to measure the induced current to obtain the speed of the change of the distance between the two plates. For example, as shown in the graph on the left side of Figure 3a, when the current in the same direction is passed into the upper pole plate and the lower pole plate, since the current direction is the same, the Magnetic fields in the same direction are generated in the spiral inductor, so that the upper and lower plates attract each other to pull the upper and lower plates in.

In addition, currents in opposite directions can also be passed through the upper pole plate and the lower pole plate. When the current directions in the upper pole plate and the lower pole plate are opposite, magnetic fields in opposite directions will be generated, so the The upper pole plate and the lower pole plate repel each other, so as to push the upper pole plate and the lower pole plate apart, thereby avoiding the addition of an elastic device in the MEMS variable capacitor to push the upper pole plate separated from the lower plate. When both ends of the upper pole plate and the lower pole plate are electrified, the magnetic induction current caused by the proximity of the pole plates can also be measured, that is, the speed at which the distance between the capacitive pole plates changes, and the motion acceleration can be measured by conversion. Change speed.

Specifically, how it works:

As shown in Figure 3d, it can work as a two-terminal device. When only connecting the first connection end 21 of the upper plate and the first connection end 23 of the lower plate, it can be regarded as a common parallel plate capacitance, so the two-pole capacitance can be measured. The distance from the board, the method measures the acceleration of the motion.

When working as a four-terminal device, the first connection end 21 of the upper plate and the second connection end 20 of the upper plate are energized, and the first connection end 23 of the lower plate is connected to the second connection end 22 of the lower plate. power ups. When the direction of the inductive current in the upper pole plate and the lower pole plate is the same, the direction of the magnetic field is the same, so that the upper pole plate and the lower pole plate attract each other. When the currents are in opposite directions, the magnetic fields are in opposite directions and repel each other. The connection method can measure changes in motion acceleration.

In addition, electricity can also be energized at both ends of the first connection end 23 of the lower pole plate and the second connection end 22 of the lower pole plate, while the first connection end 21 of the upper pole plate and the second connection end 20 of the upper pole plate current. When the distance between the two plates changes, an induced current reflecting the distance change speed will be generated in the upper plate.

Therefore, on the one hand, the electrode structure of the present invention can measure the capacitance of the two pole plates to calculate the distance between the pole plates like ordinary capacitance, which can be converted into acceleration for the acceleration sensor. On the other hand, it is also possible to measure the magnetic induction current caused by the proximity of the pole plates, that is, the speed at which the distance between the capacitive pole plates changes, and measure the change speed of the motion acceleration through conversion.

In addition, as another preferred implementation manner, the number of the spiral inductors in the upper pole plate and the lower pole plate is not limited to a certain value range, and the number of the spiral inductors in the upper pole plate and the lower pole plate Each can include one, two or more than two spiral inductors, as shown in FIG. 3e.

When the upper pole plate or the lower pole plate contains a plurality of the spiral inductors, it is preferable to select the same spiral inductors with the same setting direction, that is, the spiral directions of the spiral inductors are the same, as shown in Fig. 7, the electrode plate in this embodiment contains two spiral inductors, wherein the shapes of the two spiral inductors are exactly the same, and the setting methods are also exactly the same, when the upper pole plate and the lower pole When the plates are arranged in the above manner, the deflection as shown in the right figure will occur when the upper plate and the lower plate are energized.

Example 2

The preparation method of the movable inductive electrode structure in a specific embodiment of the present invention will be further described below with reference to Figs. 4a-4h.

First, step 201 is performed to provide a semiconductor substrate, on which a lower plane plate 201 is formed, on which a lower pole plate 202 is embedded, and the lower pole plate is a planar spiral inductor.

Specifically, as shown in Figure 4a, a semiconductor substrate (not shown in the figure) is firstly provided, wherein the semiconductor substrate can be at least one of the materials mentioned below: silicon, silicon-on-insulator (SOI) , silicon-on-insulator (SSOI), silicon-germanium-on-insulator (S-SiGeOI), silicon-germanium-on-insulator (SiGeOI) and germanium-on-insulator (GeOI), etc.

Various active devices are formed on the semiconductor substrate, for example, CMOS devices and other active devices are formed on the semiconductor substrate, and the active devices are not limited to a certain type.

Forming the lower planar plate 201 in the semiconductor substrate, wherein the method of forming the lower planar plate 201 is to form an interlayer dielectric layer on the semiconductor substrate, then pattern the dielectric layer to form grooves, and then The lower plane plate material layer is selected to fill the groove to form the lower plane plate 201. In this embodiment, the lower capacitor substrate is a preferred arrangement method, and it can also be omitted.

The material layer of the lower plane plate can be made of conductive material to form a conventional variable constant volume electrode plate in the prior art. Since the lower plane plate will not be used for electrical connection, it plays a role of fixing in this embodiment. and support the function of the lower plate 202, so conductive materials can be selected, and non-conductive materials can also be selected.

Then deposit a lower electrode material layer on the lower plane plate 201 to cover the lower plane plate 201, wherein the lower electrode material layer can be selected from copper, gold, silver, tungsten and other similar materials, preferably metal copper, which can be obtained by physical The lower electrode material layer is formed by a vapor deposition (PVD) method or an electrochemical copper plating (ECP) method, preferably by an electrochemical copper plating (ECP) method.

Then pattern the lower electrode material layer to form a spiral inductor, specifically, pattern the lower electrode material layer, for example, form a patterned photoresist layer (not shown in the figure) on the lower electrode material layer out), the pattern of the spiral inductor is formed on the photoresist layer, and then the lower electrode material layer is patterned with the photoresist layer as a mask, so as to transfer the pattern to the lower electrode material layer , to form the lower plate 202 .

In this step, the lower plane plate 201 can also be patterned to form a pattern of spiral inductors in the lower plane plate 201 , and then a lower electrode material layer is selected to fill the pattern to form the lower pole plate 202 . The method for forming the lower plate is not limited to the above two methods, and other methods can also be selected.

Step 202 is executed to deposit a sacrificial material layer 203 on the lower plane plate and the lower electrode plate.

Specifically, as shown in FIG. 4b, the sacrificial material layer 203 may be photoresist, SiO ₂ , nitrogen doped silicon carbide layer NDC (Nitrogen dopped Silicon Carbite), SiN layer or amorphous carbon material (AC), In a specific embodiment of the present invention, SiO ₂ is preferred as the sacrificial material layer.

A planarization step is performed after depositing the layer of sacrificial material, in which step a planarization method conventional in the field of semiconductor manufacturing can be used to achieve planarization of the surface. Non-limiting examples of the planarization method include a mechanical planarization method and a chemical mechanical polishing planarization method. The planarization method of chemical mechanical polishing is more commonly used.

Step 203 is executed to pattern the sacrificial material layer 203 to remove part of the sacrificial material layer 203 to expose the lower plane plate 201 .

Specifically, as shown in FIG. 4 c , after removing part of the sacrificial material layer 203 , it must be satisfied that the sacrificial material layer 203 can still completely cover the lower plane plate 201 .

Execute step 204, forming an upper plane material layer on the sacrificial material layer, forming an upper plate material layer on the upper plane material layer, and patterning the upper plate material layer to form a planar spiral inductor The upper plate 204.

Specifically, as shown in FIG. 4e, an upper plane material layer is formed on the sacrificial material layer. The upper plane material layer is preferably made of the same material as the lower plane material layer, and the forming method may also be the same, No more details.

In this step, the height of the upper plane material layer is higher than that of the sacrificial material layer 203 , and then a planarization step is performed to make the height of the upper plane material layer uniform.

Then deposit an upper plate material layer on the upper plate material layer, the upper plate material layer can be selected from copper, gold, silver, tungsten and other similar materials, preferably metal copper, and can be deposited by physical vapor deposition (PVD) method or electrochemical copper plating (ECP) method, preferably electrochemical copper plating (ECP) method to form the lower electrode material layer.

Then pattern the upper electrode material layer to form a spiral inductor, specifically, pattern the upper electrode material layer, for example, form a patterned photoresist layer (not shown in the figure) on the upper electrode material layer out), the pattern of the spiral inductor is formed on the photoresist layer, and then the upper electrode material layer is patterned with the photoresist layer as a mask, so as to transfer the pattern to the upper electrode material layer , to form the upper plate 204, as shown in FIG. 4d.

Step 205 is executed to continue depositing the upper plane plate material layer to form the upper plane plate 205 covering the upper pole plate 204 .

Specifically, as shown in FIG. 4f, continue to deposit an upper plane plate material layer on the upper pole plate 204 to fill the gap of the spiral inductor and completely cover the upper pole plate to form an upper plane plate 205 .

Wherein the upper plane plate 205 can be selected from various conductive metal materials, such as metal copper, gold, silver, tungsten, etc., because the upper plane plate 205 only plays the role of fixing and supporting, so the upper plane plate 205 also Other insulating materials can be selected, and are not limited to a certain one.

Step 206 is executed to pattern the upper plane plate 205 and one end of the upper pole plate 204 to form an opening to expose the sacrificial material layer 203 .

Specifically, as shown in FIG. 4g, the upper plane plate 205 and one end of the upper pole plate 204 are patterned to form an opening, and the opening is used to remove the pressure sensor sacrificial material layer 30 in a subsequent step to A sensor cavity is formed.

As preferably, one end of the upper plane plate 205 and the upper pole plate 204 is patterned to expose the unetched end of the sacrificial material layer 203. In this step, the conductive material layer can be etched by dry method. CF ₄ , CHF ₃ , and one of N ₂ , CO ₂ , and O ₂ can be selected as the etching atmosphere in the etching method, and the gas flow rate is CF ₄ 10-200sccm, CHF ₃ 10-200sccm, N ₂ or CO ₂ or O ₂ 10-400 sccm, the etching pressure is 30-150 mTorr, and the etching time is 5-120 s, preferably 5-60 s, more preferably 5-30 s.

Step 207 is executed to remove the sacrificial material layer to form a cavity as a dielectric of the variable capacitor.

Specifically, as shown in FIG. 4h , the sacrificial material layer 203 is removed to form a cavity between the upper plate 204 and the lower plate 202 as a dielectric of the variable capacitor.

In the specific embodiment of the present invention, dry etching, reactive ion etching (RIE), ion beam etching, and plasma etching can be selected. It is preferable to carry out dry etching by one or more RIE steps, for example, in the present invention, _N2 can be selected as the etching atmosphere, and other small amounts of gases such as _CF4 , _CO2 , _O2 can also be added at the same time, the etching pressure It can be 50-200mTorr, preferably 100-150mTorr, and the power is 200-600W. The etching time described in the present invention is 5-80s, more preferably 10-60s. In the present invention, select a larger gas flow rate simultaneously as Preferably, the flow rate of N ₂ in the present invention is 30-300 sccm, more preferably 50-100 sccm.

After the upper electrode 204 and the lower electrode 202 are formed, further steps of forming other components in the pressure sensor or acceleration sensor are included. Those skilled in the art can choose conventional steps to achieve the above purpose, and will not repeat them here.

Example 3

The preparation method of the movable inductive electrode structure in a specific embodiment of the present invention will be further described below with reference to Figs. 5a-5e.

First, step 301 is performed to provide a semiconductor substrate, on which a lower plane plate is formed, and a lower pole plate is embedded on the lower plane plate, and the lower pole plate is a planar spiral inductor.

Specifically, as shown in Figure 5a, a semiconductor substrate (not shown in the figure) is firstly provided, wherein the semiconductor substrate can be at least one of the materials mentioned below: silicon, silicon-on-insulator (SOI) , silicon-on-insulator (SSOI), silicon-germanium-on-insulator (S-SiGeOI), silicon-germanium-on-insulator (SiGeOI) and germanium-on-insulator (GeOI), etc.

Various active devices are formed on the semiconductor substrate, for example, CMOS devices and other active devices are formed on the semiconductor substrate, and the active devices are not limited to a certain type.

Forming the lower planar plate 201 in the semiconductor substrate, wherein the method of forming the lower planar plate 201 is to form an interlayer dielectric layer on the semiconductor substrate, then pattern the dielectric layer to form grooves, and then The lower plane plate material layer is selected to fill the groove to form the lower plane plate 201. In this embodiment, the lower capacitor substrate is a preferred arrangement method, and it can also be omitted.

Then deposit a lower electrode material layer on the lower plane plate 201 to cover the lower plane plate 201, wherein the lower electrode material layer can be selected from copper, gold, silver, tungsten and other similar materials, preferably metal copper, which can be obtained by physical The lower electrode material layer is formed by a vapor deposition (PVD) method or an electrochemical copper plating (ECP) method, preferably by an electrochemical copper plating (ECP) method.

Then pattern the lower electrode material layer to form a spiral inductor, specifically, pattern the lower electrode material layer, for example, form a patterned photoresist layer (not shown in the figure) on the lower electrode material layer out), the pattern of the spiral inductor is formed on the photoresist layer, and then the lower electrode material layer is patterned with the photoresist layer as a mask, so as to transfer the pattern to the lower electrode material layer , to form the lower plate 202 .

In this step, the lower plane plate 201 can also be patterned to form a pattern of spiral inductors in the lower plane plate 201 , and then a lower electrode material layer is selected to fill the pattern to form the lower pole plate 202 . The method for forming the lower plate is not limited to the above two methods, and other methods can also be selected.

Step 302 is executed, depositing a sacrificial material layer 203 on the lower plane plate and the lower electrode plate.

Specifically, as shown in FIG. 5a, the sacrificial material layer 203 may be photoresist, SiO ₂ , nitrogen doped silicon carbide layer NDC (Nitrogen dopped Silicon Carbite), SiN layer or amorphous carbon material (AC), In a specific embodiment of the present invention, SiO ₂ is preferred as the sacrificial material layer.

A planarization step is performed after depositing the layer of sacrificial material, in which step a planarization method conventional in the field of semiconductor manufacturing can be used to achieve planarization of the surface. Non-limiting examples of the planarization method include a mechanical planarization method and a chemical mechanical polishing planarization method. The planarization method of chemical mechanical polishing is more commonly used.

Step 303 is executed to pattern the sacrificial material layer 203 to remove part of the sacrificial material layer 203 to expose the lower plane plate 201 .

Specifically, as shown in FIG. 5 a , after removing part of the sacrificial material layer 203 , it must be satisfied that the sacrificial material layer 203 can still completely cover the lower plane plate 201 .

Execute step 304, forming an upper plate material layer on the sacrificial material layer, forming an upper plate material layer on the upper plate material layer, and patterning the upper plate material layer to form a planar spiral inductor The upper plate 204.

Specifically, as shown in Figure 5b, an upper plane material layer is formed on the sacrificial material layer, the upper plane material layer is preferably made of the same material as the lower plane material layer, and the forming method may also be the same, No more details.

In this step, the thickness of the upper plane material layer is relatively thin, so a stepped upper plane material layer is formed on the sacrificial material layer and the lower plane plate 201 .

Then deposit an upper plate material layer on the upper plate material layer, the upper plate material layer can be selected from copper, gold, silver, tungsten and other similar materials, preferably metal copper, and can be deposited by physical vapor deposition (PVD) method or electrochemical copper plating (ECP) method, preferably electrochemical copper plating (ECP) method to form the lower electrode material layer.

The thickness of the upper plate material layer is uniform, so the upper plate material layer is also stepped, as shown in FIG. 5c.

Then pattern the upper electrode material layer to form a spiral inductor, specifically, pattern the upper electrode material layer, for example, form a patterned photoresist layer (not shown in the figure) on the upper electrode material layer out), the pattern of the spiral inductor is formed on the photoresist layer, and then the upper electrode material layer is patterned with the photoresist layer as a mask, so as to transfer the pattern to the upper electrode material layer , to form the upper plate 204, as shown in FIG. 5c.

Step 305 is executed to pattern the upper plane plate 205 and one end of the upper pole plate 204 to form an opening to expose the sacrificial material layer 203 .

Specifically, as shown in FIG. 5d, the upper plane plate 205 and one end of the upper pole plate 204 are patterned to form an opening, and the opening is used to remove the pressure sensor sacrificial material layer 30 in a subsequent step to A sensor cavity is formed.

As preferably, one end of the upper plane plate 205 and the upper pole plate 204 is patterned to expose the unetched end of the sacrificial material layer 203. In this step, the conductive material layer can be etched by dry method. CF ₄ , CHF ₃ , and one of N ₂ , CO ₂ , and O ₂ can be selected as the etching atmosphere in the etching method, and the gas flow rate is CF ₄ 10-200sccm, CHF ₃ 10-200sccm, N ₂ or CO ₂ or O ₂ 10-400 sccm, the etching pressure is 30-150 mTorr, and the etching time is 5-120 s, preferably 5-60 s, more preferably 5-30 s.

Step 306 is executed to remove the sacrificial material layer to form a cavity as a dielectric of the variable capacitor.

Specifically, as shown in FIG. 5 e , the sacrificial material layer 203 is removed to form a cavity between the upper plate 204 and the lower plate 202 as a dielectric of the variable capacitor.

In the specific embodiment of the present invention, dry etching, reactive ion etching (RIE), ion beam etching, and plasma etching can be selected. It is preferable to carry out dry etching by one or more RIE steps, for example, in the present invention, _N2 can be selected as the etching atmosphere, and other small amounts of gases such as _CF4 , _CO2 , _O2 can also be added at the same time, the etching pressure It can be 50-200mTorr, preferably 100-150mTorr, and the power is 200-600W. The etching time described in the present invention is 5-80s, more preferably 10-60s. In the present invention, select a larger gas flow rate simultaneously as Preferably, the flow rate of N ₂ in the present invention is 30-300 sccm, more preferably 50-100 sccm.

After the upper electrode 204 and the lower electrode 202 are formed, further steps of forming other components in the pressure sensor or acceleration sensor are included. Those skilled in the art can choose conventional steps to achieve the above purpose, and will not repeat them here.

Example 4

The preparation method of the movable inductive electrode structure in a specific embodiment of the present invention will be further described below with reference to Figs. 6a-6g.

First, step 401 is performed to provide a semiconductor substrate, on which a lower plane plate is formed, and a lower pole plate is embedded on the lower plane plate, and the lower pole plate is a planar spiral inductor.

As shown in FIG. 6b , the specific forming method may refer to Embodiment 2 and Embodiment 3 and will not be repeated here.

Step 402 is executed to deposit a sacrificial material layer 203 on the lower plane plate and the lower electrode plate.

Specifically, as shown in FIG. 6c, the sacrificial material layer 203 may be photoresist, SiO ₂ , nitrogen doped silicon carbide layer NDC (Nitrogen dopped Silicon Carbite), SiN layer or amorphous carbon material (AC), In a specific embodiment of the present invention, SiO ₂ is preferred as the sacrificial material layer.

A planarization step is performed after depositing the layer of sacrificial material, in which step a planarization method conventional in the field of semiconductor manufacturing can be used to achieve planarization of the surface. Non-limiting examples of the planarization method include a mechanical planarization method and a chemical mechanical polishing planarization method. The planarization method of chemical mechanical polishing is more commonly used.

Execute step 403, patterning the sacrificial material layer 203 to form openings at both ends of the sacrificial material layer 203, exposing the lower plane plate, and removing part of the sacrificial material layer in the middle to form a groove, as shown in FIG. 6d Show.

Step 404 is executed to form an upper plane material layer and an upper plate material layer in the groove, and pattern them to form the upper plate 204 of the planar spiral inductor.

As shown in Figure 6d, the difference between Embodiment 2 and Embodiment 3 in this step is that the planar plate material layer and the upper plate material layer are simultaneously put on in this step to form the upper plate 204, the specific map The scheme method can refer to embodiment 2 and embodiment 3.

Step 405 is executed to continue depositing the upper plane plate material layer to form the upper plane plate 205 to cover the upper pole plate 204 .

Specifically, as shown in FIG. 6e , continue to deposit an upper plane plate material layer on the upper pole plate 204 to fill the gap of the spiral inductor and completely cover the upper pole plate to form an upper plane plate 205 .

Executing step 406 , patterning the upper plane plate 205 and one end of the upper pole plate 204 to form an opening to expose the sacrificial material layer 203 .

Specifically, as shown in FIG. 6f, the upper plane plate 205 and one end of the upper pole plate 204 are patterned to form an opening, and the opening is used to remove the pressure sensor sacrificial material layer 30 in a subsequent step to A sensor cavity is formed.

As preferably, one end of the upper plane plate 205 and the upper pole plate 204 is patterned to expose the unetched end of the sacrificial material layer 203. In this step, the conductive material layer can be etched by dry method. CF ₄ , CHF ₃ , and one of N ₂ , CO ₂ , and O ₂ can be selected as the etching atmosphere in the etching method, and the gas flow rate is CF ₄ 10-200sccm, CHF ₃ 10-200sccm, N ₂ or CO ₂ or O ₂ 10-400 sccm, the etching pressure is 30-150 mTorr, and the etching time is 5-120 s, preferably 5-60 s, more preferably 5-30 s.

Step 407 is executed to remove the sacrificial material layer to form a cavity as a dielectric of the variable capacitor.

Specifically, the sacrificial material layer 203 is removed to form a cavity between the upper plate 204 and the lower plate 202 as a dielectric of the variable capacitor, and a structure as shown in FIG. 6 a is obtained. For the specific removal method, reference may be made to Embodiment 2 and Embodiment 3, which will not be repeated here.

After the upper electrode 204 and the lower electrode 202 are formed, further steps of forming other components in the pressure sensor or acceleration sensor are included. Those skilled in the art can choose conventional steps to achieve the above purpose, and will not repeat them here.

In order to solve the problems existing in the prior art, the present invention provides a new MEMS movable inductance electrode structure. The electrode structure adopts a new capacitor plate structure, and the inductance is introduced into the design of the movable capacitor plate. In this state, the two inductors can move with each other, and the opposite current direction is added to the inductance on the two polar plates to generate a magnetic field in the opposite direction to push the two polar plates away. At the same time, it is also possible to apply the same current and the two plates attract each other. Therefore, the problem in the prior art that the two pole plates cannot be separated by the electrostatic force of the pole plates is solved.

On the one hand, the electrode structure of the present invention can measure the capacitance of the two pole plates to calculate the distance between the pole plates like ordinary capacitance, which can be converted into acceleration for the acceleration sensor. On the other hand, it is also possible to measure the magnetic induction current caused by the proximity of the pole plates, that is, the speed at which the distance between the capacitive pole plates changes, and measure the change speed of the motion acceleration through conversion.

Fig. 7a is a flow chart of the preparation process of the single-chip micro-electro-mechanical system described in a specific embodiment of the present invention, which specifically includes the following steps:

Step 201 provides a semiconductor substrate, on which a lower plane plate and a lower pole plate are formed, and the lower pole plate is embedded in the lower plane plate;

Step 202 depositing a sacrificial material layer on the lower plane plate and the lower plate;

Step 203 forming an upper plane material layer on the sacrificial material layer;

Step 204 forming an upper plate material layer on the upper plane plate material layer;

Step 205 patterning the upper plate material layer to form the upper plate of the planar spiral inductor;

Step 206 patterning the upper plane material layer and the upper plate to form an opening to expose the sacrificial material layer;

Step 207 removes the sacrificial material layer.

Fig. 7b is a flow chart of the preparation process of the single-chip micro-electro-mechanical system described in a specific embodiment of the present invention, which specifically includes the following steps:

Step 301 provides a semiconductor substrate, on which a lower plane plate is formed, and a lower pole plate is embedded on the lower capacitor substrate, and the lower pole plate is a planar spiral inductor;

Step 302 depositing a sacrificial material layer on the lower plane plate and the lower pole plate, and patterning, so as to remove part of the sacrificial material layer on one end to expose the lower plane plate;

Step 303 forming an upper plane plate on the sacrificial material layer;

Step 304 forming an upper plate material layer on the upper plane plate, and patterning the upper plate material layer to form the upper plate of the planar spiral inductor;

Step 305 patterning the upper plane plate and one end of the upper pole plate to form an opening to expose the unetched end of the sacrificial material layer;

Step 306 removes the sacrificial material layer.

Fig. 7c is a flow chart of the preparation process of the single-chip micro-electro-mechanical system described in a specific embodiment of the present invention, which specifically includes the following steps:

Step 401 provides a semiconductor substrate, on which a lower plane plate is formed, and a lower pole plate is embedded on the lower capacitor substrate, and the lower pole plate is a planar spiral inductor;

Step 402 depositing a layer of sacrificial material on the lower plane plate and the lower electrode plate, and patterning to form openings at both ends of the sacrificial material layer to expose the lower plane plate, and removing part of the sacrificial material located in the middle layer to form grooves;

Step 403 forming an upper plane plate material layer and an upper plate material layer in the groove, and patterning to form the upper plate of the planar spiral inductor;

Step 404 continues to deposit a layer of upper plate material to form an upper plate covering the upper plate;

Step 405 patterning the upper plane plate to expose the sacrificial material layer;

Step 406 removes the sacrificial material layer.

The present invention has been described through the above-mentioned embodiments, but it should be understood that the above-mentioned embodiments are only for the purpose of illustration and description, and are not intended to limit the present invention to the scope of the described embodiments. In addition, those skilled in the art can understand that the present invention is not limited to the above-mentioned embodiments, and more variations and modifications can be made according to the teachings of the present invention, and these variations and modifications all fall within the claimed scope of the present invention. within the range. The protection scope of the present invention is defined by the appended claims and their equivalent scope.

Claims (15)

1. MEMS can a dynamic inductance electrode structure, comprising:

Isolate top crown and the bottom crown of setting up and down, for the formation of two battery lead plates of variable capacitance in MEMS, wherein said top crown and described bottom crown all select planar spiral inductor, mutually move in energising situation to make described top crown and described bottom crown.

2. according to claim 1 can dynamic inductance electrode structure, it is characterized in that, described planar spiral inductor selects square spiral inductance coil or round screw thread inductance coil.

3. according to claim 1 can dynamic inductance electrode structure, it is characterized in that, describedly can also comprise independently inductance core by dynamic inductance electrode structure, described inductance core is positioned at the center of described planar spiral inductor.

4. according to claim 3 can dynamic inductance electrode structure, it is characterized in that, described inductance core is inductor wire.

5. according to claim 1 can dynamic inductance electrode structure, it is characterized in that, describedly can also comprise surface plate and lower plane plate by dynamic inductance electrode structure, described upper surface plate and described lower plane plate are that monoblock is arranged, and described top crown and described bottom crown are embedded in described upper surface plate and described lower plane plate respectively.

6. according to claim 1 or 5 can dynamic inductance electrode structure, it is characterized in that, described top crown with comprise two or more identical planar spiral inductor in described bottom crown.

7. according to claim 1 can dynamic inductance electrode structure, it is characterized in that, when being electrically connected the first link of described top crown and the first link corresponding to described bottom crown, be used for measuring the distance between described top crown and described bottom crown.

8. according to claim 1 can dynamic inductance electrode structure, it is characterized in that, be electrically connected the first link of described top crown, the second link, when being electrically connected the first link, second link of described bottom crown, motion mutually occur simultaneously between described top crown and described bottom crown.

9. according to claim 8 can dynamic inductance electrode structure, it is characterized in that, when described top crown is identical with inductive current in described bottom crown, described top crown and described bottom crown attract each other;

When in described top crown and described bottom crown, inductive current is contrary, described top crown and described bottom crown repel mutually.

10. according to claim 1 can dynamic inductance electrode structure, it is characterized in that, be electrically connected the first link of described bottom crown, the second link, measure the induced-current of reaction distance pace of change in the first link of described top crown, the second link.

11. 1 kinds of MEMS can the preparation method of dynamic inductance electrode structure, comprising:

There is provided Semiconductor substrate, be formed with bottom crown on the semiconductor substrate, described bottom crown is planar spiral inductor;

Described bottom crown forms sacrificial material layer;

Described sacrificial material layer forms top crown, and described top crown is planar spiral inductor;

Remove described sacrificial material layer, between described top crown and described bottom crown, form cavity.

12. methods according to claim 11, is characterized in that, described method comprises:

There is provided Semiconductor substrate, be formed with lower plane plate and bottom crown on the semiconductor substrate, described bottom crown is embedded in described lower plane plate;

Sacrificial material layer on described lower plane plate and described bottom crown;

Described sacrificial material layer forms the flat sheet bed of material;

The flat sheet bed of material forms top crown material layer on described;

Top crown material layer described in patterning, to form the described top crown of planar spiral inductor;

Described in patterning, the upper flat sheet bed of material and described top crown, to form opening, expose described sacrificial material layer;

Remove described sacrificial material layer.

13. methods according to claim 12, it is characterized in that, described method is also included on described lower plane plate and described bottom crown after sacrificial material layer, sacrificial material layer described in patterning, to remove the described sacrificial material layer of part on one end, expose described lower plane plate;

And the flat sheet bed of material and described top crown on patterning, to form opening, expose one end that described sacrificial material layer does not etch.

14. methods according to claim 13, is characterized in that, described method continues the described upper flat sheet bed of material of deposition after being also included in and forming described top crown, to form upper surface plate (205), covers described top crown.

15. methods according to claim 12, it is characterized in that, described method to be also included on described lower plane plate and described bottom crown after sacrificial material layer, sacrificial material layer described in patterning, to form opening at two ends, expose described lower capacity substrate, in the middle of described sacrificial material layer, form groove simultaneously;

The flat sheet bed of material and top crown material layer on being formed in described groove;

Capacitive plate material layer described in patterning and described top crown material layer, to form the top crown of planar spiral inductor;

Continue the upper flat sheet bed of material of deposition, to form upper surface plate, cover described top crown.