A sensor having a cavity

Abstract

A cavity sensor includes a substrate, a cavity, a sensing element, and a porous gel material. The cavity is disposed on the substrate and has a cavity wall and an internal space formed within the cavity wall. The sensing element is disposed on the cavity wall, and the porous gel material is disposed between the substrate and the cavity. The porous gel material has a porosity of not less than 80%, allowing gas communication between the internal space of the cavity and the outside environment. This forms a channel for gas to enter and exit, thereby balancing the pressure inside the cavity sensor and increasing the support of the cavity sensor, reducing the risks associated with typically using die-attach adhesive to bond the sensing element to the substrate.

Description

Technical Field

[0001] The present invention relates to a sensor, in particular to a sensor provided with a porous gel material and having a cavity. Background Art

[0002] Sensors generally refer to components that output signals based on changes in physical properties, chemical properties, or the environment, such as resistive sensors, piezoelectric sensors, thermoelectric sensors, electrochemical sensors, microwave sensors, etc. Among the aforementioned sensors, some sensors need to form a cavity structure based on the sensing principle.

[0003] A pressure sensor disclosed in U.S. Invention Patent Publication No. US9,804,046 includes a cavity formed by a molding material, a control die disposed in the cavity, and a pressure sensor die disposed on the control die. The control die and the pressure sensor die are interconnected by a wire soldering, and then an adhesive is dispensed to adhere these die and other components to a carrier substrate.

[0004] Or as disclosed in U.S. invention patent publication No. US2019 / 0336099A1, an ultrasonic device includes an ultrasonic transducer and an access hole, the ultrasonic transducer includes a substrate and a membrane, wherein the substrate and the membrane are arranged to form a sealed cavity therebetween, the access hole passes through the membrane, and the access hole is configured to provide a passage into the sealed cavity.

[0005] For the above-mentioned sensor with a cavity structure, an adhesive is usually used to fix the cavity structure on a carrier substrate for the subsequent packaging process. In fact, the adhesive is usually a die-bonding adhesive. However, when the adhesive is used for fixing, the cavity structure is easily sealed due to too many adhesive dots, which can easily cause damage to the sensor during operation; on the other hand, if the adhesive dots are too few, it is easy to cause the joint surface to fall off. Summary of the invention

[0006] The main purpose of the present invention is to solve the problem that the commonly used sensor with a cavity is easily damaged or falls off due to the use of adhesive.

[0007] To achieve the above-mentioned purpose, the present invention provides a sensor with a cavity, comprising a substrate, a cavity, a sensing element and a porous gel material. The cavity is arranged on the substrate and has a cavity wall and an internal space formed in the cavity wall, the sensing element is arranged on the cavity wall, and the porous gel material is arranged between the substrate and the cavity, and the porous gel material has a porosity of not less than 80%, so that the internal space of the cavity is connected to the outside by gas.

[0008] To achieve the above-mentioned purpose, the present invention also provides another sensor with a cavity, comprising a substrate, a cavity, a sensing element and a porous gel material. The cavity is arranged on the substrate and has a cavity wall and an internal space formed in the cavity wall, the sensing element is arranged on a top wall of the cavity, and the porous gel material is at least partially arranged in the internal space. In addition, the porous gel material has a first surface covered by the cavity wall and not exposed to the outside world and a second surface not covered by the cavity wall and exposed to the outside world, wherein the porous gel material has a porosity of not less than 80%, so that the internal space of the cavity is connected to the outside world through the second surface.

[0009] Therefore, the present invention integrates the porous gel material into the sensor and serves as a passage between the gas and the outside world. In this way, since the gas can enter and exit between the internal space and the outside world, the air pressure between the internal space and the outside world is balanced, so that the adhesive points can be fully arranged to meet the integrity of the sensing function without sacrificing the bonding degree. In addition, the present invention can fill the cavity with the porous gel material to make the cavity supportive and not easy to be damaged, and reduce the heat loss of the internal space. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] Figure 1 It is a schematic cross-sectional view of the structure of the first example of the first embodiment of the present invention.

[0011] Figure 2 It is a schematic cross-sectional view of the structure of the second example of the first embodiment of the present invention.

[0012] Figure 3 It is a schematic cross-sectional view of the structure of the third example of the first embodiment of the present invention.

[0013] Figure 4 It is a schematic cross-sectional view of the structure of the first example of the second embodiment of the present invention.

[0014] Figure 5 It is a schematic cross-sectional view of the structure of the second example of the second embodiment of the present invention.

[0015] Figure 6 It is a schematic cross-sectional view of the structure of the third example of the second embodiment of the present invention. DETAILED DESCRIPTION

[0016] The detailed description and technical contents of the present invention are now described as follows with reference to the accompanying drawings:

[0017] See also Figure 1The present invention provides a sensor with a cavity, comprising a substrate 10, a cavity 20, a sensing element 30, a porous gel material 40 and an adhesive layer 50. In the present invention, the sensor with a cavity can be any sensor with a cavity structure. According to different usage requirements, the sensor with a cavity can be selected as a temperature sensor, a gas sensor, a pressure sensor, a tire pressure gauge, a microphone, etc. In the present invention, the material of the substrate 10 can be metal, glass, ceramic, polymer or the above composite materials. For example, the substrate 10 can be made of silicon wafer, plastic, printed circuit board (PCB), fiberglass board, silicon dioxide (SiO2) or photoresist, etc.

[0018] The cavity 20 is disposed on the substrate 10. The cavity 20 includes a cavity wall 21 and an internal space 22. The internal space 22 is formed in the cavity wall 21. The cavity wall 21 includes a side wall 211 and a top wall 212 disposed on the side wall 211. The sensing element 30 is disposed on the top wall 212. In this embodiment, the side wall 211 is made of a silicon material, and the top wall 212 is made of an insulating material. The porous gel material 40 is disposed between the substrate 10 and the cavity 20. The porous gel material 40 has a thickness between 500 m 2 / g to 1200m 2 / g, and a porosity greater than 80%. In one embodiment, the porosity is between 88% and 99.8%, and the porous gel material 40 has a porosity between 0.01 g / cm 3 Up to 0.2g / cm 3 and a thermal conductivity value lower than 0.035 W / mK. The porous gel material 40 may be a silicon-based material or a hydrophobic material, wherein the silicon-based material is selected from the group consisting of silicon-based compounds such as siloxane compounds, water glass and sodium silicate. For example, the porous gel material 40 includes a silicon-based compound and an additive mixed with the silicon-based compound, and the additive is selected from the group consisting of single-layer carbon nanotubes, multi-layer carbon nanotubes, multi-layer graphene and a combination thereof. Thus, by utilizing the porosity of the porous gel material 40, the gas can easily pass through the internal space 22 of the cavity 20, and flow in and out between the internal space 22 and the outside world 60, thereby balancing the air pressure inside the sensor having a cavity.

[0019] The adhesive layer 50 includes a first adhesive layer 51 and a second adhesive layer 52. The first adhesive layer 51 is bonded between the porous gel material 40 and the substrate 10, and the second adhesive layer 52 is bonded between the cavity 20 and the porous gel material 40. The porous gel material 40 and the adhesive layer 50 can be in different structural forms such as layered or ring-shaped. The adhesive layer 50 is selected from bonding tape, bonding film, wafer bonding film, die attach film, FOD (Fingerprint On Display) film, FOW (Film Over Wire) film, solid crystal glue or other adhesive materials.

[0020] Figures 1 to 3 is a different example of the first embodiment of the present invention, and Figures 4 to 6 These are different examples of the second embodiment of the present invention.

[0021] like Figure 1 As shown, in the first example of the first embodiment of the present invention, the porous gel material 40 is formed into a layer or a sheet, and the layer extends from one side end of the side wall 211 of the cavity 20 to the other side end; the first adhesive layer 51 is also formed into a layer or a sheet, and the layer extends from one side end of the side wall 211 of the cavity 20 to the other side end. In other words, the two-dimensional geometric shapes of the porous gel material 40 and the first adhesive layer 51 on the horizontal plane correspond to each other; the second adhesive layer 52 is arranged between the porous gel material 40 and the side wall 211 and is formed into a ring corresponding to the side wall 211. The second adhesive layer 52 and the two-dimensional geometric shapes of the side wall 211 on the horizontal plane correspond to each other. The gas can be as Figure 1 The device leaves or enters the cavity 20 as shown by the arrows.

[0022] like Figure 2 As shown, in the second example of the first embodiment of the present invention, the porous gel material 40 and the first adhesive layer 51 are both formed into a layer or a sheet and correspond to the two-dimensional geometric shape of the substrate 10 on the horizontal plane; the second adhesive layer 52 is disposed between the porous gel material 40 and the side wall 211 and is formed into a ring corresponding to the side wall 211, and the second adhesive layer 52 corresponds to the two-dimensional geometric shape of the side wall 211 on the horizontal plane. The gas can be as Figure 2 The device leaves or enters the cavity 20 as shown by the arrows.

[0023] like Figure 3 As shown, in the third example of the first embodiment of the present invention, the porous gel material 40, the first adhesive layer 51, and the second adhesive layer 52 are all formed into a ring shape and correspond to the two-dimensional geometric shape of the side wall 211 on the horizontal plane. Figure 3The device leaves or enters the cavity 20 as shown by the arrows.

[0024] like Figure 4 As shown, in the first example of the second embodiment of the present invention, the porous gel material 40 includes a first part 41 and a second part 42, the first part 41 is arranged in the internal space 22, and the second part 42 is arranged between the substrate 10 and the cavity 20, the first part 41 has a first surface 411, and the second part 42 has a second surface 421, the first surface 411 is covered and not exposed to the outside world 60, and the second surface 421 is not covered and exposed to the outside world 60. In this embodiment, the second part 42 of the porous gel material 40 is formed into a layer or a sheet, and the layer extends from one side end of the side wall 211 of the cavity 20 to the other side end; the first adhesive layer 51 is also formed into a layer or a sheet, and the layer extends from one side end of the side wall 211 of the cavity 20 to the other side end. In other words, the second part 42 of the porous gel material 40 and the first adhesive layer 51 have corresponding two-dimensional geometric shapes on a horizontal plane; the second adhesive layer 52 is arranged between the second part 42 of the porous gel material 40 and the side wall 211 and is formed into a ring corresponding to the side wall 211. The second adhesive layer 52 and the side wall 211 have corresponding two-dimensional geometric shapes on a horizontal plane. In this embodiment, the first surface 411 of the first portion 41 is covered by the side wall 211, the top wall 212, the second adhesive layer 52 and the second portion 42 and is not directly connected to the outside 60. The second surface 421 (i.e., the outer side) of the second portion 42 is not covered. The first portion 41 and the second portion 42 are connected, so that the gas can be Figure 4 The device leaves or enters the cavity 20 as shown by the arrows.

[0025] like Figure 5 As shown, in the second example of the second embodiment of the present invention, the second part 42 of the porous gel material 40 and the first adhesive layer 51 are both formed into a layer or a sheet and correspond to the two-dimensional geometric shape of the substrate 10 on the horizontal plane; the second adhesive layer 52 is disposed between the second part 42 of the porous gel material 40 and the side wall 211 and is formed into a ring shape corresponding to the side wall 211, and the first adhesive layer 51 corresponds to the two-dimensional geometric shape of the side wall 211 on the horizontal plane. The gas can be as Figure 5 The device leaves or enters the cavity 20 as shown by the arrows.

[0026] like Figure 6As shown, in the third example of the second embodiment of the present invention, the porous gel material 40 is disposed in the internal space 22, and the height h1 of the porous gel material 40 is greater than the height h2 of the side wall 211, so that the porous gel material 40 is formed with a first surface 411 that is covered and not exposed to the outside 60 and a second surface 421 that is not covered and exposed to the outside 60, and the adhesive layer 50 is disposed between the porous gel material 40 and the substrate 10 to fix the porous gel material 40. The gas can be as Figure 6 The device leaves or enters the cavity 20 as shown by the arrows.

[0027] The present invention integrates the porous gel material into the sensor, so that the gas can flow in and out between the internal space and the outside, so that the air pressure between the internal space and the outside is balanced, so that the adhesive points can be fully arranged to meet the integrity of the sensing function without sacrificing the bonding degree. In addition, the present invention can fill the cavity with the porous gel material to make the cavity supportive and not easy to be damaged, and reduce the heat loss of the internal space.

Claims

1. A sensor having a cavity, characterized in that: Include: a substrate; a cavity, disposed on the substrate and having a cavity wall and an inner space formed in the cavity wall; a sensing element, disposed on a top wall of the cavity; as well as A porous gel material is arranged between the substrate and the cavity, and the porous gel material is at least partially arranged in the internal space. The porous gel material has a first surface covered by the cavity wall and not exposed to the outside world, and a second surface not covered by the cavity wall and exposed to the outside world, wherein the porous gel material has a porosity of not less than 80%, so that the internal space of the cavity is connected to the outside world through the second surface.

2. The sensor having a cavity according to claim 1, characterized in that The invention also includes a first adhesive layer disposed between the substrate and the porous gel material.

3. The sensor having a cavity according to claim 1, characterized in that: The invention also includes a second adhesive layer disposed between the porous gel material and the cavity wall.

4. The sensor having a cavity according to claim 1, characterized in that: The porous gel material has a 2 / g to 1200m 2 / g and the specific surface area between 0.01 g / cm 3 Up to 0.2g / cm 3 The density between.

5. The sensor having a cavity according to claim 1, characterized in that: The porous gel material includes a silicon-based compound and an additive mixed with the silicon-based compound, wherein the additive is selected from the group consisting of single-layer carbon nanotubes, multi-layer carbon nanotubes, multi-layer graphene and combinations thereof.

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