WO2012088823A1

WO2012088823A1 - Forming method for microelectromechanical system sensor

Info

Publication number: WO2012088823A1
Application number: PCT/CN2011/074292
Authority: WO
Inventors: 毛剑宏; 唐德明
Original assignee: 上海丽恒光微电子科技有限公司
Priority date: 2010-12-31
Filing date: 2011-05-19
Publication date: 2012-07-05
Also published as: CN102556943B; CN102556943A

Abstract

A forming method for a Microelectromechanical System (MEMS) sensor is provided. The method includes: providing a substrate, on which some MEMS sensor regions and pads adjacent to each MEMS sensor region are formed, wherein the surface of the MEMS sensor regions is formed with MEMS sensor electrodes and the surface of the pads is formed with pad electrodes (S1); depositing a dielectric layer on the substrate, wherein a first cavity and a second cavity are formed in the dielectric layer, the first cavity exposes the surface of the MEMS sensor electrodes and a movable part is formed in the first cavity and the second cavity exposes the surface of the pad electrodes (S2); cutting adjacent MEMS sensor regions to separate them, wherein the notch at least penetrates through the second cavity to expose the pad electrodes and separate the adjacent MEMS sensor (S3). That only the notch is need to break through the second cavity can separate the MEMS sensor regions, so that the cutting difficulty of the MEMS sensor is reduced.

Description

Method for forming MEMS sensor

The present application claims priority to Chinese Patent Application No. 2010-011830, filed on Dec. 31, 2010, the entire disclosure of which is hereby incorporated by reference.

Technical field

The present invention relates to the field of semiconductor manufacturing, and in particular to a method of forming a microelectromechanical sensor.

Background technique

MEMS (Microelectromechanical System) technology refers to the technology of designing, processing, manufacturing, measuring and controlling micro/nanotechnology materials. MEMS is a micro system that integrates mechanical components, optical systems, drive components, and electronic control systems into one integral unit. MEMS are commonly used in position sensors, rotating devices or sensors such as accelerometers, gyroscopes and sound sensors.

A conventional prior art electromechanical sensor typically includes a body and one or more movable members that are suspended discrete structures relative to the body, the movable members being suspended from the cantilever. The gas layer between the movable member, the main body, and the movable member and the main body constitutes a capacitance. The movable member and the main body are relatively movable, and when the movable member and the main body are relatively moved, for example, moving up and down or moving left and right, the capacitance value of the capacitor is changed, so that the continuous measurement of the capacitance value can obtain the The speed or acceleration of the movable member and the body moving relative to the left or right or moving up and down. The above-described microelectromechanical sensor for measuring the relative motion between the movable member and the body by measuring the capacitance value is also called a capacitive helium electromechanical sensor. More information on existing MEMS sensors can be found in the US patent document "US2010116057A1".

The prior art first forms a number of MEMS sensors on the same substrate, the MEMS sensor comprising a MEMS sensor region and a pad region adjacent to the MEMS sensor region; sensor.

However, in the process of manufacturing, the process of dividing the adjacent MEMS sensors is cumbersome and difficult to cut.

Summary of the invention

The problem solved by the present invention is to provide a method for forming a microelectromechanical sensor, which reduces the complexity of the fabrication process of the microelectromechanical sensor. In order to solve the above problems, the present invention provides a method for forming a microelectromechanical sensor, the microelectromechanical sensor including a microelectromechanical sensing region and a pad region adjacent thereto, including:

Providing a substrate having a plurality of MEMS sensor regions formed thereon, and a pad region adjacent to each MEMS sensor region, wherein the surface of the MEMS sensing region is formed with a microelectromechanical sensing electrode, a pad electrode is formed on a surface of the pad region;

Depositing a dielectric layer on the substrate, wherein a first cavity and a second cavity are formed in the dielectric layer, the first cavity exposing a surface of the microelectromechanical sensing electrode, in the first cavity Forming a movable member, the second cavity exposing the surface of the pad electrode;

The adjacent £ electromechanical sensor is diced and separated, the cutting opening extending through at least the second cavity until the pad electrode is exposed, separating the adjacent MEMS sensor.

Optionally, the microelectromechanical sensing electrode comprises a top electrode and a bottom electrode of the microelectromechanical sensor. Optionally, the first cavity includes a first groove and a third groove penetrating the first groove, the second cavity includes a second groove and a fourth recess penetrating the second groove groove.

Optionally, the dielectric layer comprises a first dielectric layer, a second dielectric layer and a third dielectric layer which are sequentially located on the substrate.

Optionally, the first groove and the second groove are located in the first dielectric layer, and the third groove and the fourth groove are located in the second dielectric layer.

Optionally, the depositing a dielectric layer includes forming a first interlayer dielectric layer on the substrate, and forming a first recess and a second recess in the first interlayer dielectric layer, the first A recess exposes the bottom electrode, and the second recess exposes the pad electrode.

Optionally, the first recess and the second recess are respectively filled with a first sacrificial layer and a second sacrificial layer.

Optionally, the method further includes forming a first conductive plug in the first interlayer dielectric layer, and the first conductive plug is electrically connected to the top electrode.

Optionally, the method further includes forming a movable component on the first interlayer dielectric layer, the movable component being connected to the top electrode through a first conductive plug, wherein one end of the movable component is covered with the first sacrificial layer .

Optionally, the movable component has a thickness ranging from 0.1 to 50 micrometers, and the movable component has a width ranging from 10 to 1000 micrometers.

Optionally, a second interlayer dielectric layer is formed on the first interlayer dielectric layer, and the second interlayer dielectric layer covers the movable component. Optionally, a third groove and a fourth groove are formed in the second interlayer dielectric layer, wherein the first groove and the third groove penetrate, the second groove and the fourth concave The groove is penetrated, and the third groove and the fourth groove are respectively filled with the third sacrificial layer and the fourth sacrificial layer.

Optionally, a third interlayer dielectric layer is formed on the second interlayer dielectric layer, and a first opening and a second opening are formed in the third interlayer dielectric layer, the first opening is exposed The third sacrificial layer, the second opening exposing the third sacrificial layer.

Optionally, the method further includes: introducing the etching gas through the first opening and the second opening, removing the first sacrificial layer, the second sacrificial layer, the third sacrificial layer, and the fourth sacrificial layer, after removing the sacrificial layer, The first groove and the third groove constitute a first cavity, and the second groove and the fourth groove constitute a second cavity.

Optionally, the method further includes forming a cover on the third interlayer dielectric layer, and forming a cutting opening by cutting the cover, the cutting opening extending at least through the cover and the second cavity until the pad electrode is exposed Finally, the adjacent £ electromechanical sensor is separated by the cutting opening.

Optionally, the first sacrificial layer, the second sacrificial layer, the third sacrificial layer, and the fourth sacrificial layer are made of one of amorphous carbon, photoresist, polyimide, amorphous silicon, and molybdenum. .

Optionally, the first sacrificial layer, the second sacrificial layer, the third sacrificial layer and the fourth sacrificial layer are processed by a plasma enhanced chemical vapor deposition process, and the reaction temperature is 350 to 450 degrees Celsius.

Optionally, the method for removing the first sacrificial layer, the second sacrificial layer, and the third sacrificial layer is removed by plasma ashing using oxygen ions or nitrogen ions.

Optionally, the material of the first interlayer dielectric layer, the second interlayer dielectric layer, and the third interlayer dielectric layer is silicon oxide, silicon oxynitride, silicon carbide, silicon nitride, or a combination thereof.

Optionally, the top electrode, the bottom electrode and the pad electrode are made of metal and have a thickness ranging from 0.05 to 10 micrometers, and the metal is silver, aluminum, copper, titanium, platinum, gold, nickel, cobalt or a combination thereof. .

Optionally, the first conductive plug is made of a metal, and the metal is one or more of tungsten, gold, silver, copper, aluminum, titanium, and nickel.

Compared with the prior art, the present invention has the following advantages: by forming a second cavity on the pad region, the second cavity completely exposes the pad electrode, and when the MEMS sensor is subsequently cut, only It is necessary to make the cutting opening penetrate through the second cavity to perform separation, reduce the cutting difficulty of the MEMS sensor, and reduce the cutting cost of the MEMS sensor. DRAWINGS

1 is a flow chart showing a method of forming a microelectromechanical sensor according to an embodiment of the present invention;

2 to FIG. 15 are schematic cross-sectional views showing a method of forming a germanium electromechanical sensor according to an embodiment of the present invention.

detailed description

The prior art cutting the adjacent microelectromechanical sensor specifically includes forming a cover on the MEMS sensor region and the pad region, and by cutting the cover until the exposed portion of the pad region is completely exposed Pad electrodes to separate adjacent MEMS sensors. The inventors have found that the pad electrode of the pad region is covered with an insulating material, and the insulating material on the pad electrode must be completely removed by wet etching or dry etching to completely expose the solder. The surface of the disk electrode, and due to the large thickness of the insulating material located above the pad electrode, increases the complexity of the cutting process.

In order to solve the above problems, the present invention provides a method for forming a microelectromechanical sensor, the microelectromechanical sensor including a microelectromechanical sensing region and a pad region adjacent thereto, and the forming method includes:

Providing a substrate, the substrate is formed with a plurality of MEMS sensor regions, and a pad region adjacent to each MEMS sensor region, wherein the surface of the MEMS sensing region is formed with a MEMS sensing electrode a pad electrode is formed on a surface of the pad region;

The present invention forms a second cavity on the pad region, the second cavity completely exposing the pad electrode, and when the microelectromechanical sensor is subsequently cut, it is only necessary to make the cutting port penetrate the second cavity Separation can be performed, the cutting difficulty of the MEMS sensor is reduced, and the cutting cost of the MEMS sensor is reduced.

The above described objects, features and advantages of the present invention will become more apparent from the aspects of the appended claims. Specific details are set forth in the following description in order to provide a thorough understanding of the invention. However, the present invention can be implemented in a variety of other ways than those described herein, and those skilled in the art can make similar promotion without departing from the scope of the present invention. Therefore, the invention is not limited by the specific embodiments disclosed below.

1 is a schematic flow chart of a method for forming a microelectromechanical sensor according to an embodiment of the present invention, specifically, As shown in Figure 1, it includes:

Performing step SI, providing a substrate, the substrate is formed with a plurality of MEMS device regions, and a pad region adjacent to each MEMS sensor region, wherein the surface of the MEMS sensing region is formed with a micro-electromechanical transmission a sensing electrode, a surface of the pad region is formed with a pad electrode;

Step S2, forming a first interlayer dielectric layer on the substrate, the first interlayer dielectric layer is formed with a first groove and a second groove, the first groove exposing a bottom electrode, The second recess exposes the pad electrode, and the first recess and the second recess are also respectively filled with the first sacrificial layer and the second sacrificial layer, and the first inter-layer dielectric layer is further formed with the first a conductive plug, the first conductive plug being electrically connected to the top electrode;

Step S3, forming a movable member on the first interlayer dielectric layer, the movable member is connected to the top electrode through the first conductive plug, and one end of the movable member is covered with the first sacrificial layer; Step S4, forming a second interlayer dielectric layer on the first interlayer dielectric layer, and the second interlayer dielectric layer covers the movable component;

Step S5, a third groove and a fourth groove are formed in the second interlayer dielectric layer, wherein the first groove and the third groove penetrate, the second groove and the fourth groove Throughout, and the third groove and the fourth groove are respectively filled with a third sacrificial layer and a fourth sacrificial layer;

Step S6, forming a third interlayer dielectric layer on the second interlayer dielectric layer, and forming a first opening and a second opening in the third interlayer dielectric layer, the first opening exposing a third sacrificial layer, the second opening exposing the third sacrificial layer;

Step S7, the etching gas is introduced through the first opening and the second opening, and the first sacrificial layer, the second sacrificial layer, the third sacrificial layer and the fourth sacrificial layer are removed, and after the sacrificial layer is removed, the first The groove and the third groove constitute a first cavity, and the second groove and the fourth groove constitute a second cavity;

Step S8, forming a cover on the third interlayer dielectric layer, and forming a cutting opening through the cover, the cutting opening at least penetrating the cover and the second cavity until the pad electrode is exposed, and finally passes The cutting port separates adjacent £ electromechanical sensors.

The invention will be described in detail below with reference to the accompanying drawings. First, as shown in Fig. 2, a substrate 100 is provided. The substrate 100 of the present invention may be a semiconductor substrate such as silicon, germanium or gallium arsenide, or the substrate 100 may also be a glass substrate. In this embodiment, the substrate 100 is a semiconductor substrate. The following will be described by taking a substrate as a semiconductor substrate as an example.

With continued reference to FIG. 1, two or more micro-electromechanical devices are formed on the substrate on the substrate 100. The sensor device region 1, each of the microelectromechanical sensor regions is also formed with a pad region 2 adjacent thereto. This figure shows only one MEMS sensor area 1 and its adjacent pad area 2. The pad region 2 is used to connect the MEMS sensor region 1 to an external device.

A control circuit (not shown) is formed in the substrate 100, and the control circuit is configured to provide a control signal to each device formed on the semiconductor substrate 100. The control circuit may be formed in the semiconductor substrate and may be formed on the substrate Inside another semiconductor substrate. As a preferred embodiment, the control circuit is formed in the semiconductor substrate 100 shown in Fig. 2, which saves chip area and is more suitable for a microdisplay system.

With continued reference to FIG. 2, the substrate 100 is further formed with electrodes correspondingly connected to the control circuit, including a microelectromechanical sensing electrode located in the microelectromechanical sensor region 1, including a top electrode 120 and a bottom electrode.

130, and a pad electrode 110 located in the pad region 2.

As an embodiment, the material of the pad electrode 110, the top electrode 120, and the bottom electrode 130 is metal. The thickness ranges from 0.05 to 10 microns, and the metal is silver, aluminum, copper, titanium, platinum, gold, nickel, cobalt or a combination thereof.

As shown in FIG. 3, a first interlayer dielectric layer 200 is formed on the substrate 100, and the first interlayer dielectric layer 200 covers the pad electrode 110, the top electrode 120 and the bottom electrode 130 on the substrate 100. . The material of the first interlayer dielectric layer 200 is silicon oxide, silicon oxynitride, silicon carbide, silicon nitride or a combination thereof.

As shown in FIG. 4, the first interlayer dielectric layer 200 is patterned, and a first recess 210 and a second recess 220 are formed in the first interlayer dielectric layer 200. The first recess 210 exposes the bottom electrode 130, and the first recess 210 may expose the bottom electrode 130 in whole or in part. The second recess 220 exposes the pad electrode 110, and the second recess 220 may expose the pad electrode 110 in whole or in part.

As shown in FIG. 5, a sacrificial layer is filled in the first recess 210 and the second recess 220 to form a first sacrificial layer 211 and a second sacrificial layer 221, respectively. In this embodiment, an interlayer dielectric layer is first formed, and then a recess is formed in the interlayer dielectric layer to fill the sacrificial layer. As another embodiment, a sacrificial layer may be formed first, and then a recess is formed in the sacrificial layer. The groove forms an interlayer dielectric layer. Because the sacrificial layer is located at a large ratio and the filling difficulty is low, it is preferable to form an interlayer dielectric layer first, and then form a groove in the interlayer dielectric layer to fill Sacrifice layer.

Wherein, the first sacrificial layer 211 and the second sacrificial layer 221 formed by filling are filled in a subsequent process. The cavity formed over the bottom electrode 130 and the cavity above the pad electrode 110 are removed by an ashing process or other processes, wherein the cavity on the pad electrode 110 can be easily followed. A dicing process by which the pad electrode 110 is exposed.

As a preferred embodiment of the present invention, the sacrificial layer is made of one of amorphous carbon, photoresist, polyimide, amorphous silicon, and molybdenum. In this embodiment, the sacrificial layer is made of amorphous carbon, which can be fabricated by a common chemical vapor deposition process in a CMOS process, and can be removed by a plasma ashing process in a CMOS process.

Specifically, as an embodiment, the first sacrificial layer 211 and the second sacrificial layer 221 may use a plasma enhanced chemical vapor deposition (PECVD) process, and the specific parameters are: a temperature range of 350 ° C to 450 ° C, The reaction gases include: C3H6 and HE2.

Since the first sacrificial layer 211 and the second sacrificial layer 221 are fabricated by a plasma enhanced chemical vapor deposition process, the first sacrificial layer 211 and the second sacrificial layer 221 may be redundant after deposition. The first sacrificial layer 211 and the second sacrificial layer 221 cover the surface of the first interlayer dielectric layer 200, and a planarization process is required to remove excess sacrificial layer on the surface of the first interlayer dielectric layer 200. In order to form a flat surface, it is advantageous for the subsequent process steps. The planarization process is a chemical mechanical polishing process. The chemical mechanical polishing process is the same as the prior art, and is well known to those skilled in the art and will not be described in detail herein.

As shown in FIG. 6, the first interlayer dielectric layer 200 is again patterned, an opening is formed in the interlayer dielectric layer 200, and the opening is metal-filled to form the first conductive plug 230. The bottom of the first conductive plug 230 is electrically connected to the top electrode 120. The material of the first conductive plug 230 is metal, and the metal is one or more of tungsten, gold, silver, copper, aluminum, titanium, and nickel.

As shown in FIG. 7, a movable member layer 300 of a 敫 electromechanical sensor is formed on the first interlayer dielectric layer 200, and the material of the movable member layer 300 is metal gold, silver, copper, aluminum, titanium, or the like. It is preferably aluminum. The movable component 300 may also be a conductive non-metal such as polysilicon, amorphous silicon, polysilicon, conductive glass, etc., or a combination of a metal and an insulating medium or a combination of a conductive non-metal and an insulating medium, wherein the insulating member 300 The medium may be SiO 2 , SiON, SiN x, SiC, SiOC or the like. Among them, in the case of a metal material, it can be formed by a chemical vapor deposition process.

Referring to FIG. 8, the metal layer is etched to form a movable member 310, and the movable member 310 passes A first conductive plug 230 is coupled to the top electrode 130 and receives a control signal transmitted by a control circuit located within the substrate 100 through the top electrode 130. The movable member 310 simultaneously covers a part of the surface of the first sacrificial layer 230. The movable member 310 has a thickness ranging from 0.1 to 50 micrometers, and the movable member 310 has a width ranging from 10 to 1000 micrometers.

As shown in FIG. 9, a second interlayer dielectric layer 400 is formed on the first interlayer dielectric layer 200, and the second interlayer dielectric layer 400 covers the movable member 310. The material of the second interlayer dielectric layer 400 is silicon oxide, silicon oxynitride, silicon carbide, silicon nitride or a combination thereof.

As shown in FIG. 10, the second interlayer dielectric layer 400 is patterned, and a third recess 410 and a fourth recess 420 are formed in the second interlayer dielectric layer 400, the first recess The groove and the third groove 410 are penetrated, and the second groove and the fourth groove 420 are penetrated. The movable component 310 is located in the third recess 410, and the dielectric layers of the top and sidewall of the movable component 310 are removed, only the bottom and second interlayer dielectric layer 200 or the first sacrificial layer 220 contact.

As shown in FIG. 11, the sacrificial layer material is filled in the third recess 410 and the fourth recess 420 to form a third sacrificial layer 411 and a fourth sacrificial layer 421, respectively. The third sacrificial layer 411 covers the movable member 310.

In this embodiment, an interlayer dielectric layer is first formed, and then a recess is formed in the interlayer dielectric layer to fill the sacrificial layer. As another embodiment, a sacrificial layer may be formed first, and then a recess is formed in the sacrificial layer. The groove forms an interlayer dielectric layer. Because the sacrificial layer is located at a large ratio and the filling difficulty is low, it is preferable to form an interlayer dielectric layer first, and then form a groove in the interlayer dielectric layer to fill Sacrifice layer.

The third sacrificial layer 411 and the fourth sacrificial layer 421 formed by the filling are removed by an ashing process or other processes in a subsequent process to form a cavity above the bottom electrode 130, and located in the pad. A cavity above the electrode 110, wherein the cavity on the pad electrode 110 can facilitate a subsequent dicing process by which the pad electrode 110 can be exposed.

Specifically, as an embodiment, the third sacrificial layer 411 and the fourth sacrificial layer 421 may utilize a plasma enhanced chemical vapor deposition (PECVD) process, specifically the temperature range is: 350 ° C ~ 450 ° C, the reaction gases include: C3H6 and HE2.

Since the third sacrificial layer 411 and the fourth sacrificial layer 421 are fabricated by a plasma enhanced chemical vapor deposition process, the third sacrificial layer 411 and the fourth sacrificial layer 421 may be redundant after deposition. The third sacrificial layer 411 and the fourth sacrificial layer 421 cover the surface of the second interlayer dielectric layer 400, and a planarization process is required to remove excess sacrificial layer on the surface of the second interlayer dielectric layer 400 to form The flat surface facilitates the subsequent process steps. The flat chemical process is a chemical mechanical polishing process. The chemical mechanical polishing process is the same as the prior art, and is well known to those skilled in the art and will not be described in detail herein.

As shown in FIG. 12, a third interlayer dielectric layer 500 is formed on the second interlayer dielectric layer 200, and the third interlayer dielectric layer 500 has a thickness ranging from 0.1 μm to 10 μm. The third interlayer dielectric layer 500 is patterned to form a first opening 510 and a second opening 520. The material of the third interlayer dielectric layer 500 is silicon oxide, silicon oxynitride, silicon carbide, silicon nitride or a combination thereof.

As shown in FIG. 13, the first sacrificial layer 211, the second sacrificial layer 221, the third sacrificial layer 411, and the fourth sacrificial layer 421 are removed by the etching gas passing through the first opening 510 and the second opening 520. The first groove 211, the second groove 221, the third groove 411, and the fourth groove 421 are exposed. The cavity above the bottom electrode 130 is a first cavity, the first cavity is a first groove 211 and a third groove 411 penetrating therethrough, and a cavity above the pad electrode 110 is The second cavity is a second groove 221 and a fourth groove 420 therethrough.

The etching of the sacrificial layer is an ashing process using a nitrogen-containing or oxygen-containing plasma. As an embodiment, the etching of the sacrificial layer includes an etching method of the first sacrificial layer 211, the second sacrificial layer 221, the third sacrificial layer 411, and the fourth sacrificial layer 421, including: the removing material is Oxygen, the generated plasma is oxygen ions, and the etching process has a temperature range of 150 ° C to 450 ° C. At this temperature, the dense amorphous carbon does not undergo intense combustion, but can be oxidized to carbon dioxide gas. The first sacrificial layer 211, the second sacrificial layer 221, the third sacrificial layer 411, and the fourth sacrificial layer 421 can be completely removed, and the rest of the device is not affected.

As shown in FIG. 14, a cover layer 600 is formed on the third interlayer dielectric layer 500, and the cover layer 600 has a thickness ranging from 1 micrometer to 500 micrometers, and the cover layer 600 is mainly used for covering and protecting the Microelectromechanical sensing area. The cap layer formed on the pad region needs to be removed in a subsequent process.

As shown in FIG. 15, a cutting opening is formed on the cover layer 600, and adjacent 敫 electromechanical sensors are separated by the cutting opening, wherein the cutting opening penetrates at least the covering layer and the first The two cavities are exposed until the surface of the pad electrode 110 is exposed.

Further, the cutting as shown in Fig. 15 can also start from the bottom of the substrate 100 until the second cavity is exposed, so that the microelectromechanical sensor and the microelectromechanical sensor adjacent thereto are separated.

The present invention forms a second cavity on the pad region, the second cavity completely exposes the pad electrode, and when the MEMS sensor is subsequently cut, it is only necessary to make the cutting port penetrate the cover and the first The two cavities can be separated, and the wet etching or dry etching is not required to remove the insulating material located on the pad region, the cutting difficulty of the micro electromechanical sensor is reduced, and the micro electromechanical sensor is reduced. Cutting costs.

The present invention has been disclosed in the above preferred embodiments, but it is not intended to limit the invention, and the present invention may be made without departing from the spirit and scope of the invention. The scope of protection should be determined by the scope defined by the claims of the present invention.

Claims

Rights request

A method of forming a microelectromechanical sensor, the MEMS sensor comprising a MEMS sensing region and a pad region adjacent thereto, and comprising:

Providing a substrate having a plurality of microelectromechanical sensor regions formed thereon, and a pad region adjacent to each of the microelectromechanical sensor regions, wherein the surface of the microelectromechanical sensing region is formed with a microelectromechanical sensing electrode, a pad electrode is formed on a surface of the pad region;

An adjacent microelectromechanical sensor is diced and separated, the cutting opening extending through at least the second cavity until the pad electrode is exposed, separating the adjacent MEMS sensor.

2. The method of forming a microelectromechanical sensor according to claim 1, wherein the microelectromechanical sensing electrode comprises a top electrode and a bottom electrode of the microelectromechanical sensor.

3. The method of forming a microelectromechanical sensor according to claim 1, wherein the first cavity comprises a first groove and a third groove penetrating the first groove, the second cavity A second groove and a fourth groove penetrating the second groove are included.

4. The method of forming a microelectromechanical sensor according to claim 3, wherein the dielectric layer comprises a first dielectric layer, a second dielectric layer, and a third dielectric layer sequentially on the substrate.

The method of forming a microelectromechanical sensor according to claim 4, wherein the first groove and the second groove are located in the first dielectric layer, and the third groove and the fourth groove are located Within the second dielectric layer.

6. The method of forming a microelectromechanical sensor according to claim 5, wherein the depositing the dielectric layer comprises forming a first interlayer dielectric layer on the substrate, and in the first interlayer dielectric layer A first recess and a second recess are formed, the first recess exposing the bottom electrode, and the second recess exposing the pad electrode.

7. The method of forming a microelectromechanical sensor according to claim 6, wherein the first sacrificial layer and the second sacrificial layer are filled in the first recess and the second recess, respectively.

8. The method of forming a microelectromechanical sensor according to claim 7, further comprising forming a first conductive plug in the first interlayer dielectric layer, the first conductive plug and the top The electrodes are electrically connected.

9. The method of forming a microelectromechanical sensor according to claim 8, further comprising forming a movable member on the first interlayer dielectric layer, the movable member passing through the first conductive plug and the top The electrodes are connected, and one end of the movable member is covered with a first sacrificial layer.

The method of forming a MEMS sensor according to claim 9, wherein the movable member has a thickness ranging from 0.1 to 50 μm, and the movable member has a width ranging from 10 to 1000 μm.

The method of forming a microelectromechanical sensor according to claim 10, wherein a second interlayer dielectric layer is formed on the first interlayer dielectric layer, and the second interlayer dielectric layer covers the Movable parts.

The method of forming a microelectromechanical sensor according to claim 11, wherein a third groove and a fourth groove are formed in the second interlayer dielectric layer, wherein the first groove and The third groove penetrates, the second groove and the fourth groove penetrate, and the third groove and the fourth groove are respectively filled with the third sacrificial layer and the fourth sacrificial layer.

The method of forming a microelectromechanical sensor according to claim 12, wherein a third interlayer dielectric layer is formed on the second interlayer dielectric layer and formed in the third interlayer dielectric layer a first opening and a second opening, the first opening exposing the third sacrificial layer, and the second opening exposing the third sacrificial layer

The method of forming a microelectromechanical sensor according to claim 13, further comprising: introducing an etching gas through the first opening and the second opening to remove the first sacrificial layer, the second sacrificial layer, After the sacrificial layer is removed, the first recess and the third recess constitute a first cavity, and the second recess and the fourth recess constitute a second cavity.

The method of forming a microelectromechanical sensor according to claim 14, further comprising forming a cover on the third interlayer dielectric layer, and forming a cutting opening by cutting the cover, the cutting opening being at least The cover and the second cavity are passed through until the pad electrode is exposed, and the adjacent germanium electromechanical sensor is finally separated by the cutting port.

The method of forming a MEMS sensor according to claim 15, wherein the first sacrificial layer, the second sacrificial layer, the third sacrificial layer, and the fourth sacrificial layer are made of amorphous carbon and lithography. One of glue, polyimide, amorphous silicon and molybdenum.

The method of forming a microelectromechanical sensor according to claim 16, wherein the first sacrificial layer, the second sacrificial layer, the third sacrificial layer, and the fourth sacrificial layer are processed by a plasma enhanced chemical vapor deposition process, The reaction temperature is 350 to 450 degrees Celsius.

The method of forming a microelectromechanical sensor according to claim 17, wherein the first sacrificial layer, the second sacrificial layer, and the third sacrificial layer are removed by plasma ash using oxygen ions or nitrogen ions. Removal.

The method of forming the MEMS sensor according to any one of claims 1 to 18, wherein the material of the first interlayer dielectric layer, the second interlayer dielectric layer, and the third interlayer dielectric layer is Silicon oxide, silicon oxynitride, silicon carbide, silicon nitride or a combination thereof.

The method of forming a microelectromechanical sensor according to any one of claims 1 to 18, wherein the top electrode, the bottom electrode and the pad electrode are made of metal and have a thickness ranging from 0.05 to 10 micrometers. The metal is silver, aluminum, copper, titanium, platinum, gold, nickel, cobalt or a combination thereof.

The method of forming a microelectromechanical sensor according to claim 8 or 9, wherein the first conductive plug is made of metal, and the metal is tungsten, gold, silver, copper, aluminum, titanium, One or more of nickel.