Micro-electro-mechanical sensing device and manufacturing method thereof

Abstract

The invention discloses a micro-electro-mechanical sensing device and a manufacturing method thereof. The micro-electro-mechanical sensing device comprises a substrate, a plurality of supporting structures and a sensing structure. The plurality of support structures are disposed on the substrate. The sensing structure is supported by the plurality of supporting structures and is arranged above the substrate. The sensing structure comprises a first dielectric layer, an electrode layer, a sensing layer and a second dielectric layer. The first dielectric layer has a dielectric top surface, and the dielectric top surface is coplanar with the support top surface of each support structure. The electrode layer is disposed on the first dielectric layer and is in direct contact with the plurality of support structures. The sensing layer is arranged on the first dielectric layer, and the projection of the sensing layer towards the direction of the substrate is not overlapped with the supporting structure. The second dielectric layer is arranged on the electrode layer and the sensing layer, wherein the first dielectric layer and the second dielectric layer are made of the same material.

Description

Technical Field

[0001] The invention relates to a micro-electromechanical system sensing device and a manufacturing method thereof. Background Art

[0002] A MEMS sensor is a microelectromechanical system (MEMS) with sensing functions, whose operating range and size are within the micrometer scale. General sensing elements, such as infrared sensing elements used to measure temperature, often require special support structures (such as anchor points) to suspend above the substrate to reduce conduction heat dissipation, and vacuum packaging to reduce convection heat dissipation in the air.

[0003] Traditionally, anchors are often designed with a large contact area and a thin and long support leg with a large tilt angle to allow the film to be stably deposited on a surface with a height difference. The disadvantage of this manufacturing process and structure is that the anchor occupies a large area (more than 5 microns by 5 microns), so it does not meet the requirements of today's component sizes (about 12 to 25 microns). Summary of the invention

[0004] In view of the above, the present invention provides a micro-electro-mechanical system sensing device and a manufacturing method thereof.

[0005] According to an embodiment of the present invention, a micro-electromechanical sensing device comprises a substrate, a plurality of supporting structures and a sensing structure. The plurality of supporting structures are arranged on the substrate, and each supporting structure has a supporting bottom surface and a supporting top surface respectively located at two opposite ends, and the supporting bottom surface is connected to the substrate. The sensing structure is supported by the plurality of supporting structures and is arranged above the substrate. The sensing structure comprises a first dielectric layer, an electrode layer, a sensing layer and a second dielectric layer. The first dielectric layer has a dielectric top surface, and the dielectric top surface is coplanar with the supporting top surface of each of the plurality of supporting structures. The electrode layer is arranged on the first dielectric layer and directly contacts the plurality of supporting structures. The sensing layer is arranged on the first dielectric layer and its projection toward the substrate does not overlap with the plurality of supporting structures. The second dielectric layer is arranged on the electrode layer and the sensing layer, and the materials of the first dielectric layer and the second dielectric layer are the same.

[0006] A method for manufacturing a micro-electromechanical sensing device according to an embodiment of the present invention comprises: forming a sacrificial layer on a substrate; forming a first dielectric layer on the sacrificial layer; embedding a plurality of supporting structures in the sacrificial layer and the first dielectric layer, so that a supporting bottom surface of each of the plurality of supporting structures is connected to the substrate, and a supporting top surface of each of the plurality of supporting structures is coplanar with a dielectric top surface of the first dielectric layer, wherein the supporting bottom surface and the supporting top surface are respectively located at two opposite ends; forming an electrode layer and a sensing layer on the first dielectric layer, wherein the electrode layer directly contacts the plurality of supporting structures, and a projection of the sensing layer toward the substrate does not overlap with the plurality of supporting structures; forming a second dielectric layer on the electrode layer and the sensing layer, wherein the second dielectric layer is made of the same material as the first dielectric layer; and opening holes in the first dielectric layer, the electrode layer, and the second dielectric layer to release the sacrificial layer.

[0007] Through the above structure, the MEMS sensing device disclosed in this case can have a stress balance effect by disposing two dielectric layers of the same material relative to the electrode layer and the sensing layer, thereby maintaining the uniformity of the overall height. The manufacturing method of the MEMS sensing device disclosed in this case can provide a simplified manufacturing process, thereby reducing the difficulty of production and improving the manufacturing yield of the chip.

[0008] The above description of the content of the present invention and the following description of the implementation modes are used to demonstrate and explain the spirit and principle of the present invention, and to provide a further explanation of the scope of the patent application of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] Figure 1 A three-dimensional structural diagram of a micro-electromechanical system sensing device according to an embodiment of the present invention;

[0010] Figure 2 A top view of a micro-electro-mechanical system sensing device according to an embodiment of the present invention;

[0011] Figure 3 A micro-electromechanical system sensing device according to an embodiment of the present invention is shown. Figure 2 A schematic cross-sectional view of the section line A-A';

[0012] Figure 4 A flowchart of a method for manufacturing a micro-electro-mechanical system sensing device according to an embodiment of the present invention;

[0013] Figure 5 for Figure 4 A schematic diagram of the states of the micro-electromechanical sensing device shown in steps S1 and S2;

[0014] Figure 6 and Figure 7 for Figure 4A schematic diagram of the state of the micro-electromechanical sensing device shown in step S3;

[0015] Figure 8 for Figure 4 A schematic diagram of the state of the micro-electromechanical sensing device depicted in steps S4 and S5;

[0016] Fig. 9 and Fig.10 for Figure 4 A schematic diagram of the state of the micro-electromechanical sensing device shown in step S6;

[0017] Fig.11 A schematic structural diagram of a micro-electromechanical system sensing device according to another embodiment of the present invention;

[0018] Figures 12a to 12e Schematic diagrams of various implementations of the support structure of the micro-electromechanical system sensing device of the present invention;

[0019] Fig.13 is a cross-sectional schematic diagram of a micro-electromechanical system sensing device according to another embodiment of the present invention;

[0020] Fig.14 A schematic diagram of the three-dimensional structure of a micro-electromechanical system sensing device according to another embodiment of the present invention;

[0021] Fig.15 A flowchart of a method for manufacturing a micro-electro-mechanical system sensing device according to another embodiment of the present invention;

[0022] Figures 16 to 20 for Fig.15 A schematic diagram of the states of the micro-electromechanical sensing device during the manufacturing process illustrated in steps S6 to S9;

[0023] Fig.21 FIG. 1 is a graph showing the relationship between the size of a columnar structure and a phase angle of a micro-electro-mechanical system sensing device according to another embodiment of the present invention.

[0024] Explanation of symbols

[0025] 1,1':MEMS sensing device

[0026] 11:Substrate

[0027] 111: Read circuit layer

[0028] 1111: Read chip

[0029] 12: Support structure

[0030] 121: Support bottom

[0031] 122: Support top surface

[0032] 13: Sensing structure

[0033] 130: Sensing unit

[0034] 131: first dielectric layer

[0035] 1310: Dielectric top surface

[0036] 1311,1312,1313: First sublayer

[0037] 132: Electrode layer

[0038] 133: Sensing layer

[0039] 134: Second dielectric layer

[0040] 1341,1342,1343: Second sublayer

[0041] 14: Sacrificial layer

[0042] 15:Through hole

[0043] 16: Opening

[0044] 17: Package cover

[0045] 171, 171a, 171b, 171c, 171d: Columnar structure

[0046] 172: Connecting part

[0047] 172a, 172b: Upper cover connection part

[0048] SA: Sense Array

[0049] A': Intercept

[0050] D: Direction

[0051] O: origin

[0052] PCB: Circuit Board

[0053] S1~S6,S7~S9: Steps DETAILED DESCRIPTION

[0054] The detailed features and advantages of the present invention are described in detail in the following embodiments, and the contents are sufficient to enable anyone familiar with the relevant art to understand the technical content of the present invention and implement it accordingly, and according to the contents disclosed in this specification, claims and drawings, anyone familiar with the relevant art can easily understand the relevant purposes and advantages of the present invention. The following examples further illustrate the viewpoints of the present invention in detail, but do not limit the scope of the present invention in any viewpoint.

[0055] The MEMS sensing device described in one or more embodiments of the present invention may not be limited to a specific sensing application, and an appropriate material layer may be selected as a sensing layer according to different sensing applications, such as temperature sensing, gas sensing, pressure sensing, and light sensing.

[0056] Please refer to Figure 1 and Figure 2 , Figure 1 is a three-dimensional structural diagram of a micro-electromechanical system sensing device according to an embodiment of the present invention. Figure 2 FIG. 4 is a top view of a micro-electro-mechanical system sensing device according to an embodiment of the present invention.

[0057] like Figure 1 and Figure 2 As shown, the micro-electromechanical sensing device 1 includes a substrate 11, a plurality of supporting structures 12 and a sensing structure 13. The substrate 11 may be, but is not limited to, a silicon substrate including a circuit structure (e.g., a reading circuit layer). The plurality of supporting structures 12 may include two supporting columns respectively disposed at two diagonal corners of the micro-electromechanical sensing device 1, and may be made of a conductive material, such as, but not limited to, a metal material. The number, location, shape, and area of ​​the supporting columns of the plurality of supporting structures 12 may be adjusted according to actual applications to stabilize the mechanical structure of the supporting sensing structure 13, and are not limited in this case. The sensing structure 13 may be divided into two side regions and a central region. The two side regions of the sensing structure 13 are directly connected to the supporting structure 12 and have an elongated channel, which is mainly used as a path for signal connection and for releasing the sacrificial layer. The central area of ​​the sensing structure 13 is suspended above the substrate 11 and has a sensing layer, which is mainly used to sense environmental changes (such as changes in temperature, gas, pressure, light, etc.) to generate sensing electrical signals, and in the embodiment where the supporting structure 12 is implemented with a conductive material, the sensing electrical signals can be transmitted to the reading circuit layer of the substrate 11 through the two side areas of the sensing structure 13 and the supporting structure 12. Figure 1 and Figure 2 The comb-shaped area in the central area shown may be the area where the sensing layer is set. It should be particularly noted that: Figure 1 and Figure 2 The geometric shape of the sensing structure 13 is only shown for example, and the design may be adjusted according to actual needs.

[0058] The following description will focus on the stacking relationship between the layers of the MEMS sensing device 1 along the direction (normal vector) of the substrate 11. Figure 3 , Figure 3 A micro-electromechanical system sensing device according to an embodiment of the present invention is shown along Figure 2 Schematic cross-sectional view along the line AA'.

[0059] like Figure 3As shown, each of the multiple support structures 12 of the micro-electromechanical sensing device 1 is disposed on the substrate 11 and can be a solid column of a conductive material. Each support structure 12 has a support bottom surface 121 and a support top surface 122 located at two opposite ends, respectively, wherein the support bottom surface 121 is connected to the substrate 11. The sensing structure 13 is supported by the support top surface 122 of the support structure 12 and is disposed above the substrate 11. The substrate 11 is, for example, a silicon substrate, and can include a readout circuit layer 111, wherein the readout circuit layer 111 can include a readout integrated circuit (ROIC). The support structure 12 can be a conductive material, in particular, tungsten metal, so that the support structure 12 can be directly electrically connected to the electrode layer 132 and the readout circuit layer 111. The support structure 12 preferably has a small tilt angle, and is more preferably substantially perpendicular to the substrate 11, thereby having a small footprint, so that the suspension height of the sensing structure 13 is easily controlled.

[0060] The sensing structure 13 includes a first dielectric layer 131, an electrode layer 132, a sensing layer 133 and a second dielectric layer 134. The first dielectric layer 131 has a dielectric top surface 1310, and the dielectric top surface 1310 is coplanar with the support top surface 122 of the support structure 12. The electrode layer 132 is disposed on the first dielectric layer 131 and directly contacts the support structure 12. The sensing layer 133 is disposed on the first dielectric layer 131 and its projection toward the substrate 11 does not overlap with the support structure 12. By disposing the first dielectric layer 131 and the second dielectric layer 134 having the same material relative to the electrode layer 132 and the sensing layer 133, the sensing structure 13 can have the effect of forming a stress balance, thereby maintaining the uniformity of the overall height of the micro-electromechanical sensing device 1. In particular, at the support structure 12, the first dielectric layer 131 and the second dielectric layer 134 can be roughly symmetrical with the electrode layer 132 as the axis, providing a better stress balance effect. It should also be noted that Figure 3 The electrode layer 132 is exemplarily shown to be disposed on the sensing layer 133, however, in other embodiments, the sensing layer 133 may be disposed on the electrode layer 132, that is, the present case does not limit the stacking order of the electrode layer 132 and the sensing layer 133. The second dielectric layer 134 is disposed on the electrode layer 132 and the sensing layer 133, wherein the first dielectric layer 131 and the second dielectric layer 134 are made of the same material.

[0061] Further, the first dielectric layer 131 and the second dielectric layer 134 may be a single material layer or a composite material layer. In the embodiment where the first dielectric layer 131 and the second dielectric layer 134 are implemented with a composite material layer, the first dielectric layer 131 includes a plurality of first sub-layers, the second dielectric layer 134 includes a plurality of second sub-layers, and the material composition of the first sub-layers along the stacking direction is the same as the material composition of the second sub-layers along the opposite direction of the stacking direction. The stacking direction may refer to the stacking direction of the first dielectric layer 131, the electrode layer 132, and the second dielectric layer 134. Preferably, the first dielectric layer 131 and the second dielectric layer 134 may have the same thickness to form a symmetrical structure.

[0062] The material of the sensing structure 13 can be adjusted according to the application. Taking the application of infrared light sensing to measure temperature as an example, the first dielectric layer 131 and the second dielectric layer 134 are each infrared light absorption layers, which can be composed of silicon dioxide and / or silicon nitride. The material of the electrode layer 132 can be, for example, titanium nitride (TiN). The sensing layer 133 can be a material whose resistance changes with temperature. Through the above structure, the first dielectric layer 131 and the second dielectric layer 134 of this embodiment absorb the infrared light emitted by the target and change the temperature. After the temperature of the sensing layer 133 changes, its resistance value changes accordingly. The reading circuit layer 111 then reads the change in resistance value through the support structure 12 and the electrode layer 132 with conductive material and converts the signal into a corresponding temperature change to achieve the function of temperature sensing.

[0063] Preferably, the MEMS sensing device 1 does not include any dielectric layer other than the first dielectric layer 131 and the second dielectric layer 134. In addition, the portion of each of the plurality of support structures 12 located between the substrate 11 and the first dielectric layer 131 is preferably not covered by a non-conductive material. Any of the above structural designs can simplify the manufacturing process and improve the yield.

[0064] Please refer to Figure 4 , Figure 4 FIG. 1 is a flow chart of a method for manufacturing a micro-electromechanical system sensing device according to an embodiment of the present invention. Figure 4As shown, the manufacturing method of the micro-electromechanical sensing device includes step S1: forming a sacrificial layer on a substrate; step S2: forming a first dielectric layer on the sacrificial layer; step S3: embedding a plurality of supporting structures in the sacrificial layer and the first dielectric layer, so that a supporting bottom surface of each of the plurality of supporting structures is connected to the substrate, and the supporting top surfaces of the plurality of supporting structures are coplanar with a dielectric top surface of the first dielectric layer, wherein the supporting bottom surface and the supporting top surface are respectively located at two opposite ends; step S4: forming an electrode layer and a sensing layer on the first dielectric layer, wherein the electrode layer directly contacts the plurality of supporting structures, and the projection of the sensing layer toward the substrate does not overlap with the plurality of supporting structures; step S5: forming a second dielectric layer on the electrode layer and the sensing layer, wherein the second dielectric layer is made of the same material as the first dielectric layer; and step S6: opening holes in the first dielectric layer, the electrode layer and the second dielectric layer to release the sacrificial layer.

[0065] Please combine Figure 4 Reference Figure 5 , Figure 5 is based on Figure 4 Schematic diagram of the state of the micro-electromechanical sensing device depicted in steps S1 and S2 in FIG. In step S1, a substrate 11 including a read circuit layer 111 may be prepared first, and a sacrificial layer 14 may be formed on the read circuit layer 111 of the substrate 11, wherein the read circuit layer 111 may be formed on the substrate 11 by a standard complementary metal oxide semiconductor (CMOS) manufacturing process, and a read chip 1111 may be provided in the read circuit layer. The thickness of the sacrificial layer 14 formed above may be 1.4 microns to 2.5 microns, wherein the material of the sacrificial layer 14 may be, for example but not limited to, an amorphous silicon material, and the formation method thereof may adopt a deposition manufacturing process. In step S2, a first dielectric layer 131 may be formed on the sacrificial layer 14 by a deposition manufacturing process. In the micro-electromechanical sensing device as an infrared light sensing element, the first dielectric layer 131 will serve as a lower radiation absorption layer.

[0066] Please combine Figure 4 Reference Figure 6 and Figure 7 , Figure 6 and Figure 7 is based on Figure 4Schematic diagram of the state of the micro-electromechanical sensing device depicted in step S3 of FIG. In step S3, it may include: forming at least one through hole 15 in the sacrificial layer 14 and the first dielectric layer 131; depositing a material in the at least one through hole 15; and performing a planarization process with the dielectric top surface 1310 of the first dielectric layer 131 as a stop surface to remove part of the material. The through hole 15 may be formed by an etching process, wherein the etching process stops at the topmost layer of the reading chip 1111 of the reading circuit layer 111. Through step S3, the material of the support structure 12 (especially a conductive material, such as tungsten metal) can be deposited in the through hole 15, so that the support structure 12 is electrically connected to the reading chip 1111 of the reading circuit layer 111 of the substrate 11, and a chemical mechanical polishing (CMP) process is performed with the dielectric top surface 1310 of the first dielectric layer 131 as the stop surface to remove excess material and stop at the dielectric top surface 1310 of the first dielectric layer 131, so that the support top surface 122 of the support structure 12 is coplanar with the dielectric top surface 1310 of the first dielectric layer 131.

[0067] Please combine Figure 4 Reference Figure 8 , Figure 8 is based on Figure 4 Schematic diagram of the state of the micro-electromechanical sensing device depicted in steps S4 and S5. In step S4, an electrode layer 132 and a sensing layer 133 may be formed on the first dielectric layer 131 and the support structure 12, wherein the electrode layer 132 directly contacts the support structure 12, and the projection of the sensing layer 133 toward the substrate 11 does not overlap with the support structure 12. It should be noted that Figure 8 The example in which the sensing layer 133 is deposited on the electrode layer 132 is shown. However, in other embodiments, the sensing layer 133 may also be deposited on the first dielectric layer 131 and below the electrode layer 132. In step S5, a second dielectric layer 134 may be formed on the electrode layer 132 and the sensing layer 133, wherein the second dielectric layer 134 is made of the same material as the first dielectric layer 131. Figure 8 The upper surface of the second dielectric layer 134 is flat, but the present invention is not limited thereto. For example, the second dielectric layer 134 may be raised upward at a position corresponding to the sensing layer 133 and have a higher height. Thus, a film structure covering the top surface of the support structure 12 can be formed by using the first dielectric layer 131 and the second dielectric layer 134 of the same material to ensure that the structure is stable and does not deform when suspended. The electrode layer 132 is directly connected to the support structure 12 without the need for an additional metal layer.

[0068] Please combine Figure 4 Reference Fig. 9 and Fig.10 , Fig. 9 and Fig.10 is based on Figure 4 Schematic diagram of the state of the micro-electromechanical sensing device in step S6. In step S6, the shape of the infrared light sensing device (micro-electromechanical sensing device) including the elongated channel, the radiation absorption surface, etc. can be defined and etched on the first dielectric layer 131, the electrode layer 132 and the second dielectric layer 134 to form the opening 16. Then, the sacrificial layer 14 is removed by etching to make the sensing structure 13 of the infrared light sensing device (micro-electromechanical sensing device) suspended.

[0069] Preferably, in the process of the manufacturing method of the above-mentioned micro-electromechanical sensing device, the formation of dielectric layers other than the first dielectric layer 131 and the second dielectric layer 134 may not be included, so as to maintain the film layer structure covering the top surface of the support, ensure that the structure is stable and does not deform when suspended, and simplify the manufacturing process. In the above process, the first dielectric layer 131 and the second dielectric layer 134 can each be an infrared light absorption layer, and the sensing structure 133 is a material whose resistance changes with temperature. The support structure 12 is a conductive material, specifically tungsten metal, and the support structure 12 is a solid cylinder, and the manufacturing method does not include covering the portion of the support structure 12 located between the substrate 11 and the first dielectric layer 131 with a non-conductive material.

[0070] Please refer to Fig.11 , Fig.11 FIG. 1 is a schematic diagram of a micro-electromechanical sensing device according to another embodiment of the present invention. Fig.11As shown, the first dielectric layer 131 includes a plurality of first sub-layers 1311, 1312, and 1313, and the second dielectric layer 134 includes a plurality of second sub-layers 1341, 1342, and 1343, and the material composition of the plurality of first sub-layers 1311, 1312, and 1313 along a stacking direction D is the same as the material composition of the plurality of second sub-layers 1341, 1342, and 1343 along the opposite direction of the stacking direction D. In other words, the first sub-layer 1311 and the second sub-layer 1341 are made of the same material; the first sub-layer 1312 and the second sub-layer 1342 are made of the same material; and the first sub-layer 1313 and the second sub-layer 1343 are made of the same material. Specifically, the material of the first sublayer 1311 and the second sublayer 1341 may be silicon dioxide; the material of the first sublayer 1312 and the second sublayer 1342 may be silicon nitride; the material of the first sublayer 1313 and the second sublayer 1343 may be silicon dioxide. The above-mentioned composite film layer can improve the absorption rate of the dielectric layer for infrared light. In this embodiment, the material of the first sublayer 1311 and the second sublayer 1341 is the same (silicon dioxide), and the material of the first sublayer 1311 and the second sublayer 1341 is the same (silicon dioxide), but the present case is not limited to this. In addition, in this embodiment, the thickness of the first sublayer 1311 and the second sublayer 1341 is approximately the same (for example, 40 nanometers); the thickness of the first sublayer 1312 and the second sublayer 1342 is approximately the same (for example, 165 nanometers); the thickness of the first sublayer 1313 and the second sublayer 1343 is approximately the same (for example, 40 nanometers). This material and the symmetrical thickness structure can balance the stress of the composite film layer and keep the sensing structure stable.

[0071] Please refer to Figures 12a to 12e , Figures 12a to 12e Various implementations of the support structure of the micro-electromechanical sensing device of the present invention are shown. In this embodiment, the metal column as the support structure is used to conduct the reading circuit layer connected below and the sensing layer above in signal communication to read the change in resistance value. Through the above-mentioned flattening and coating structure design, the supporting top surface (upper surface) and the radiation absorption surface (upper surface of the second dielectric layer) of the metal column are both flat surfaces (the height difference is less than 2 nanometers), which meets the requirements of CMOS manufacturing process. The manufacturing process of this case can avoid the height difference of the structure, which causes uneven thin film deposition, or residues of photoresist, manufacturing process by-products, etc. The thin film stack of the manufacturing process of this case covers the upper end of the metal column, which also enhances the strength of the suspended structure.

[0072] Fig.12a The supporting structure 12 and the surrounding sensing structure 13 are shown, in which the metal pillars having a rectangular cross section are arranged in a direction substantially perpendicular to the elongated channel. Figure 12b The supporting structure 12 and the surrounding sensing structure 13 are shown, in which the metal pillars having a rectangular cross section are arranged in a direction substantially parallel to the elongated channel. Fig.12cA support structure 12 of metal pillars having a square cross-section with a small area (1 micron by 1 micron) is shown, which is particularly suitable for use in situations where the overall size of the component is small. Fig.12d and Fig.12e The supporting structure 12 having a plurality of metal pillars and the surrounding sensing structure 13 are shown, wherein Fig.12d The support structure 12 comprises two metal pillars at one corner. Fig.12e The supporting structure 12 includes six metal pillars at one corner. The supporting structure 12 with multiple metal pillars is particularly suitable for maintaining a relatively stable overall structure of the component under a specific wiring frequency.

[0073] Please refer to Fig.13 and Fig.14 , Fig.13 is a cross-sectional schematic diagram of a micro-electromechanical system sensing device according to another embodiment of the present invention. Fig.14 FIG. 1 is a schematic diagram of a three-dimensional structure of a micro-electromechanical system sensing device according to another embodiment of the present invention. Fig.13 and Fig.14 As shown, the micro-electromechanical sensing device 1' including the substrate 11, the supporting structure 12 and the sensing structure 13 may further include a packaging cover 17, which covers a sensing array SA formed by the sensing structure 13 and the supporting structure 12, and is sealed with the substrate 11 to form a accommodating space S, wherein at least one of an inner surface of the packaging cover 17 facing the accommodating space S and an outer surface relative to the inner surface has a plurality of columnar structures 171.

[0074] In this embodiment, the sensing structure 13 is composed of a plurality of sensing units 130 arranged in an array; each sensing unit 130 includes a portion of the first dielectric layer, a portion of the second dielectric layer, a portion of the electrode layer and a portion of the sensing layer. The sensing units 130 and the supporting structure 12 together form a sensing array SA.

[0075] In this embodiment, the structure of the micro-electromechanical sensing device 1 is Figure 1 The micro-electromechanical sensing device 1 may be basically the same. The material of the package cover 17 may be an infrared light transparent material, such as a silicon material. The package cover 17 may be covered on the sensing array SA by metal bonding, and a accommodating space S is formed between the package cover 17 and the substrate 11. In this example, the package cover 17 has a plurality of columnar structures 171 on an outer surface relative to the inner surface, but in other embodiments, the inner surface of the package cover 17 may also have a plurality of columnar structures, or both the inner surface and the outer surface may have a plurality of columnar structures, and the present case is not limited thereto. The plurality of columnar structures 171 may have different sizes, for example, columnar structures 171a, 171b, 171c, and 171d from wide to narrow may be periodically arranged along the radial direction of the package cover 17, but are not limited thereto.

[0076] Specifically, the package cover 17 is used to package the MEMS sensor device 1' using the wafer level packaging (WLP) technology, and the accommodating space S can be a vacuum space. Thus, by forming a plurality of columnar structures for imaging on the package cover 17 of the wafer level packaging, the present invention can avoid packaging and integrating a larger additional lens group with the sensor device, thereby achieving the effect of miniaturizing the size of the overall MEMS sensor device 1'.

[0077] Please refer to Fig.15 , Fig.15 FIG. 1 is a flow chart of a method for manufacturing a micro-electromechanical sensing device according to another embodiment of the present invention. Fig.15 As shown, the manufacturing method of the micro-electromechanical sensing device may further include, after the aforementioned step S6: step S7: providing a packaging cover; step S8: etching a plurality of columnar structures on at least one of an inner surface of the packaging cover and an outer surface relative to the inner surface; and step S9: covering the packaging cover above the sensing array, and sealing the packaging cover and the common substrate to form a containing space.

[0078] Please combine Fig.15 refer to Figures 16 to 20 , Figures 16 to 20 is based on Fig.15 The state diagram of the manufacturing process of the micro-electromechanical sensing device is shown in steps S6 to S9. Fig.16 As shown, in step S6, after releasing the sacrificial layer, the unpackaged part of the micro-electromechanical sensing device 1' can be formed, wherein the plurality of sensing units 130 of the sensing structure 13 form a sensing array. The substrate 11 can be a wafer, and the substrate 11 can be disposed on a circuit board PCB. Fig.17 As shown, in step S7, a packaging cover 17 may be provided. Fig.18 As shown, in step S8, a plurality of columnar structures 171 may be etched on at least one of an inner surface of the package cover 17 and an outer surface opposite to the inner surface. Fig.19 As shown, in step S9, the package cover 17 can be covered above the sensing array, and a containing space can be formed by sealing between the package cover 17 and the substrate 11, wherein the inner surface faces the containing space. Specifically, the cover connecting parts 172a and 172b of the package cover 17 can be combined with each other by metal bonding to form a connecting part 172, so as to form a containing space in a sealed manner.

[0079] In particular, the execution order of step S8 of etching to form a plurality of columnar structures and step S9 of performing wafer-level packaging can be reversed. Fig.18In the embodiment of forming a plurality of columnar structures 211 on the inner surface of the package cover 21, etching can be performed first and then packaging. In another example, if a plurality of columnar structures are to be formed on the outer surface of the package cover 21, packaging can be performed first and then etching. Fig. 20 As shown in the example, if a plurality of columnar structures 211 are to be formed on both the outer surface and the inner surface of the package cover 21, the inner surface of the package cover 21 can be etched first, then packaged, and then the outer surface of the package cover 21 can be etched again.

[0080] The above-mentioned method of etching to form a columnar structure can be specifically implemented by dry etching or wet etching, and this case does not impose any restrictions. The following exemplarily describes the geometric parameters that need to be considered in the design of forming multiple columnar structures to meet imaging requirements, but this case is not limited to this. Please refer to equation (1), which describes the formula for the phase difference generated by the columnar structures set at various positions on the surface of the package cover on the imaging plane (sensing array). In equation (1), is the phase difference, is the wavelength of incident light, r is the distance between the columnar structure and the center point, and f is the imaging focal length of multiple columnar structures.

[0081] Relation (1):

[0082]

[0083] From equation (1), it can be concluded that columnar structures at different positions (different r) will produce different phase differences ( ). Further, according to the different phase differences of the columnar structures at different positions, the geometric dimensions of the columnar structures at different positions can be determined. Fig.21 , Fig.21 A graph showing the relationship between the size of a columnar structure and a phase angle of a MEMS sensing device according to another embodiment of the present invention. Fig.21 The graph is based on the relationship between the column width and the phase angle of a columnar structure in the shape of a "rectangular column". In other embodiments, the relationship between the size and the phase angle of a columnar structure in other shapes can also be obtained, and the present invention is not limited thereto. Fig.21 , which depicts the relationship between the column width and the phase angle when the column height (H) is 9.8, 10, and 10.2 microns, respectively. According to this chart and the above relationship (1), the geometric dimensions of the columnar structures at different positions can be determined, that is, the size of each of the plurality of columnar structures can be determined according to the imaging focal length (f) and the position (r).

[0084] For example, Fig.19The columnar structure includes four columnar structures 171a, 171b, 171c, and 171d with different column widths, arranged to form - to The phase difference period, the phase difference period closest to the origin O is composed of two columnar structures 171a, one columnar structure 171b, two columnar structures 171c and one columnar structure 171d; then, the phase difference period farthest from the origin is composed of one columnar structure 171a, one columnar structure 171b, one columnar structure 171c and one columnar structure 171d; finally, the phase difference period farthest from the origin is composed of one columnar structure 171a, one columnar structure 171c and one columnar structure 171d; therefore, the farther from the origin O, the shorter the length of a single phase difference period. In other words, in the phase difference period far from the origin O, the columnar structures are arranged in a narrower range, the number of columnar structures may be less, or the columnar width types of the columnar structures in the phase difference period are less. Generally speaking, based on the above relationship (1), as the position of the columnar structure deviates more from the center point (r is larger), the size change of the columnar structure can be more drastic. In this embodiment, the geometric center of the MEMS sensing device 1 ′ is used as the origin O, but the origin can be designed to have different positions according to requirements and is not limited to the geometric center.

[0085] Through the above structure, the MEMS sensing device disclosed in this case can have a stress balance effect and maintain the uniformity of the overall height by setting two dielectric layers of the same material relative to the electrode layer and the sensing layer. The manufacturing method of the MEMS sensing device disclosed in this case can provide a simplified manufacturing process, thereby reducing the difficulty of production and improving the yield of chip manufacturing. In addition, by using a support structure made of metal material and not coated with additional dielectric material, it can be used to conduct the electrode layer and the reading chip in the substrate as a reading signal channel in addition to the support purpose. The dielectric layer formed by the composite material can also improve the infrared light absorption rate. The manufacturing method of the MEMS sensing device disclosed in this case can reduce the difficulty of production and improve the yield of chip manufacturing by setting the support top surface of the support structure and the dielectric top surface of the first dielectric layer to be coplanar. The MEMS sensing device and its manufacturing method disclosed in this case can be packaged using wafer-level packaging technology, and a plurality of columnar structures are etched on the surface of the package cover to modulate the incident light wavefront phase and image the sensing array formed by the sensing structure without the need for additional optical lenses. In this way, it is possible to avoid packaging and integrating a lens group with a relatively large volume with the sensing device, thereby achieving the effect of miniaturizing the size of the overall optical image sensor.

Claims

1. A micro-electromechanical sensing device, comprising: substrate; A plurality of support structures are disposed on the substrate, and each of the support structures has a support bottom surface and a support top surface respectively located at two opposite ends, and the support bottom surface is connected to the substrate; and A sensing structure is supported by the supporting structures and disposed above the substrate, and the sensing structure comprises: A first dielectric layer having a dielectric top surface coplanar with the support top surface of each of the support structures; An electrode layer, disposed on the first dielectric layer and directly contacting the supporting structures; A sensing layer is disposed on the first dielectric layer and its projection toward the substrate does not overlap with the supporting structures; and The second dielectric layer is disposed on the electrode layer and the sensing layer, wherein the first dielectric layer and the second dielectric layer are made of the same material.

2. The microelectromechanical sensing device as claimed in claim 1, wherein the first dielectric layer comprises a plurality of first sub-layers, the second dielectric layer comprises a plurality of second sub-layers, and the material composition of the first sub-layers along a stacking direction is the same as the material composition of the second sub-layers along a direction opposite to the stacking direction. 3 . The micro-electromechanical system sensing device as claimed in claim 1 , comprising no dielectric layer other than the first dielectric layer and the second dielectric layer. 4 . The micro-electromechanical sensing device as claimed in claim 1 , wherein the first dielectric layer and the second dielectric layer are each an infrared light absorption layer, and the sensing layer is made of a material whose resistance changes with temperature. 5 . The micro-electromechanical system sensing device as claimed in claim 1 , wherein the support structures are made of conductive material and are electrically connected to the electrode layer. 6 . The micro-electromechanical system sensing device as claimed in claim 1 , wherein each of the support structures is a solid column made of a conductive material, and a portion of each of the support structures located between the substrate and the first dielectric layer is not covered by a non-conductive material.

7. The micro-electromechanical sensing device as claimed in claim 1, wherein the sensing structure and the supporting structures form a sensing array, and the micro-electromechanical sensing device further comprises: The packaging cover covers the sensing array and is sealed with the substrate to form a containing space. in, At least one of an inner surface of the package cover facing the accommodating space and an outer surface opposite to the inner surface is provided with a plurality of columnar structures. 8 . The micro-electromechanical system sensing device as claimed in claim 7 , wherein the accommodating space is a vacuum space. 9 . The micro-electromechanical sensing device as claimed in claim 7 , wherein the columnar structures have a focal length, each of the columnar structures has a position, and a size of each of the columnar structures is determined according to the focal length and the position. 10 . The micro-electromechanical system sensing device as claimed in claim 7 , wherein the inner surface and the outer surface of the package cover both have the columnar structures.

11. A method for manufacturing a micro-electromechanical system sensing device, comprising: forming a sacrificial layer on the substrate; forming a first dielectric layer on the sacrificial layer; Embedding a plurality of support structures in the sacrificial layer and the first dielectric layer, so that a support bottom surface of each of the support structures is connected to the substrate, and a support top surface of each of the support structures is coplanar with a dielectric top surface of the first dielectric layer, wherein the support bottom surface and the support top surface are located at two opposite ends respectively; An electrode layer and a sensing layer are formed on the first dielectric layer, wherein the electrode layer directly contacts the supporting structures, and a projection of the sensing layer toward the substrate does not overlap the supporting structures. forming a second dielectric layer on the electrode layer and the sensing layer, wherein the second dielectric layer is made of the same material as the first dielectric layer; and Opening holes in the first dielectric layer, the electrode layer and the second dielectric layer to release the sacrificial layer.

12. The method for manufacturing a micro-electromechanical sensing device as claimed in claim 11, wherein embedding the support structures in the sacrificial layer so that the support bottom surface of each of the support structures is connected to the substrate, and the support top surface of each of the support structures located at the opposite end to the support bottom surface is coplanar with the dielectric top surface of the first dielectric layer comprises: forming at least one through hole in the sacrificial layer and the first dielectric layer; depositing a material in the at least one through hole; and A planarization process is performed using the dielectric top surface of the first dielectric layer as a stop surface to remove a portion of the material.

13. The method for manufacturing a micro-electromechanical sensing device as described in claim 11, wherein forming the first dielectric layer on the sacrificial layer includes forming a plurality of first sub-layers on the sacrificial layer along a stacking direction, and forming the second dielectric layer on the electrode layer and the sensing layer includes forming a plurality of second sub-layers on the electrode layer and the sensing layer along the stacking direction, and the material composition of the first sub-layers along the stacking direction is the same as the material composition of the second sub-layers along the opposite direction of the stacking direction. 14 . The method for manufacturing a micro-electromechanical system sensing device as claimed in claim 11 , comprising excluding the step of forming a dielectric layer other than the first dielectric layer and the second dielectric layer. 15 . The method for manufacturing a micro-electromechanical system sensing device as claimed in claim 11 , wherein the first dielectric layer and the second dielectric layer are infrared light absorbing layers, and the sensing layer is made of a material whose resistance changes with temperature. 16 . The method for manufacturing a micro-electro-mechanical system sensing device as claimed in claim 11 , wherein the support structures are made of conductive material. 17 . The method for manufacturing a micro-electromechanical system sensing device as claimed in claim 11 , wherein each of the support structures is a solid column made of a conductive material, and the method does not include coating a portion of each of the support structures between the substrate and the first dielectric layer with a non-conductive material.

18. The method for manufacturing a micro-electromechanical system sensing device according to claim 11, further comprising: Provide a package cover; Etching a plurality of columnar structures on at least one of an inner surface of the package cover and an outer surface opposite to the inner surface; and The package cover is covered above the sensing array, and the package cover and the substrate are sealed to form a containing space, wherein: The inner surface faces the accommodating space. 19 . The method for manufacturing a micro-electromechanical system sensing device as claimed in claim 18 , wherein the micro-electromechanical system has a focal length, each of the columnar structures has a position, and the size of each of the columnar structures is determined according to the focal length and the position. 20 . The method for manufacturing a micro-electro-mechanical system sensing device as claimed in claim 18 , wherein the accommodating space is a vacuum space.

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