CN217931511U - Humidity sensing structure and humidity sensor - Google Patents
Humidity sensing structure and humidity sensor Download PDFInfo
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- CN217931511U CN217931511U CN202222009760.1U CN202222009760U CN217931511U CN 217931511 U CN217931511 U CN 217931511U CN 202222009760 U CN202222009760 U CN 202222009760U CN 217931511 U CN217931511 U CN 217931511U
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Abstract
The utility model provides a humidity sensing structure and humidity transducer aims at separating the base plate at first humidity sensitive electrode place and the base plate at second humidity sensitive electrode place to the mode that adopts the flip-chip bonding will first base plate with fixed connection between the second base plate makes at least one sense wet dielectric layer with the parallel wet surface of sense of first base plate and second base plate and air direct contact for the speed that the hydrone spreads to the wet dielectric layer, thereby improves the humidity transducer response speed who has this humidity sensing structure.
Description
Technical Field
The utility model relates to a humidity transducer field, in particular to humidity sensing structure, humidity transducer and humidity sensing structure's manufacturing method.
Background
Humidity is the amount of water vapor in the atmosphere at a certain temperature. The physical quantity is widely used in military, meteorological agriculture, industry, medical treatment, building, household appliances and other aspects.
Humidity sensors are devices that can convert humidity into electrical signals that can be received and processed by external devices, including capacitive, resistive, piezoresistive, and other humidity sensors, among which capacitive sensors are the most widely used because of their convenient, sensitive, and low cost characteristics. The working principle of the capacitive humidity sensor is as follows: after the electrolyte adsorbs water vapor molecules, the dielectric constant of the mixed medium changes, thereby causing the change of capacitance.
Fig. 1 is a schematic cross-sectional view of a conventional humidity sensing structure. As shown in fig. 1, the humidity sensing structure includes a sandwich structure, which has been widely used due to its excellent sensitivity performance, but has a slow response speed to water vapor. Specifically, in the humidity sensing structure, the humidity sensitive medium layer 3' is wrapped between the upper and lower electrodes 2', 4', and external moisture needs to cross the barrier formed by the upper electrode 4' to enter the sensitive humidity sensitive medium layer 3', which seriously affects the response characteristics of the humidity sensor having the humidity sensing structure.
Accordingly, there is a need for improvements in the art.
SUMMERY OF THE UTILITY MODEL
The utility model discloses aim at solving one of the technical problem that exists among the prior art at least, provide a microphone subassembly and electronic equipment.
The purpose of the utility model is realized by adopting the following technical scheme:
according to an aspect of the utility model, a humidity sensing structure is provided, include: the first substrate and the second substrate are oppositely arranged; a first humidity-sensitive electrode located on a side of the first substrate facing the second substrate; a second humidity-sensitive electrode on a side of the second substrate facing the first substrate; at least one moisture sensitive dielectric layer disposed between the first moisture sensitive electrode and the second moisture sensitive electrode; a humidity-sensitive surface of the at least one humidity-sensitive dielectric layer parallel to the first and second substrates is in direct contact with air; the second substrate is a PCB substrate.
Further, along the direction perpendicular to the plane of the first substrate, the projections of the first humidity sensitive electrode, the second humidity sensitive electrode and the at least one humidity sensitive medium layer at least partially overlap.
Optionally, the at least one humidity sensitive dielectric layer comprises only one humidity sensitive dielectric layer, which is located on the side of the first humidity sensitive electrode facing away from the first substrate with an air gap between the humidity sensitive dielectric layer and the second humidity sensitive electrode, or which is located on the side of the second humidity sensitive electrode facing away from the second substrate with an air gap between the humidity sensitive dielectric layer and the first humidity sensitive electrode.
Optionally, the humidity sensing structure further comprises an insulating medium layer; the humidity-sensitive electrode is arranged on the first substrate, the insulating medium layer is arranged between the humidity-sensitive medium layer and the first humidity-sensitive electrode in the direction perpendicular to the plane of the first substrate under the condition that the humidity-sensitive medium layer is arranged on one side, away from the first substrate, of the first substrate, or the humidity-sensitive medium layer is arranged between the humidity-sensitive medium layer and the second humidity-sensitive electrode in the direction perpendicular to the plane of the second substrate under the condition that the humidity-sensitive medium layer is arranged on one side, away from the second substrate, of the second humidity-sensitive electrode. Optionally, the at least one moisture-sensitive media layer comprises a first moisture-sensitive media layer and a second moisture-sensitive media layer; the first humidity sensitive dielectric layer is located on one side, away from the first substrate, of the first humidity sensitive electrode, the second humidity sensitive dielectric layer is located on one side, away from the second substrate, of the second humidity sensitive electrode, and an air gap is formed between the first humidity sensitive dielectric layer and the second humidity sensitive dielectric layer.
Optionally, the humidity sensing structure further includes a first insulating dielectric layer and a second insulating dielectric layer; the first insulating medium layer is positioned between the first humidity sensitive medium layer and the first humidity sensitive electrode, and the second insulating medium layer is positioned between the second humidity sensitive medium layer and the second humidity sensitive electrode along the direction perpendicular to the plane where the first substrate and the second substrate are positioned. Furthermore, the first substrate and the second substrate are fixedly connected through a bonding structure.
Further, the bonding structure includes: at least one first conductive bump, each first conductive bump being located on a side of the first substrate facing the second substrate; at least one second conductive bump, each second conductive bump being located on a side of the second substrate facing the first substrate; the at least one first conductive bump and the at least one second conductive bump are in one-to-one correspondence and are bonded, and in a plane perpendicular to the first substrate, the projection of each first conductive bump is overlapped with the projection of each second conductive bump.
Optionally, each first conductive bump is bonded to each corresponding second conductive bump through a conductive solder ball.
Furthermore, the first humidity-sensitive electrode is electrically connected with each corresponding first conductive bump through a trace, and the second humidity-sensitive electrode is electrically connected with each corresponding second conductive bump through a trace.
Optionally, two through hole electrical connection structures are further disposed on the second substrate, one of the through hole electrical connection structures is electrically connected to the second humidity sensitive electrode through a trace, and the other through hole electrical connection structure is electrically connected to the second conductive bump through a trace.
Optionally, a projection of the first humidity-sensitive electrode and/or the second humidity-sensitive electrode is located within a projection of the at least one humidity-sensitive medium layer along a direction perpendicular to a plane in which the first substrate and the second substrate are located.
Optionally, the first substrate is further provided with at least one first through hole penetrating through the first humidity-sensitive electrode, and/or the second substrate is further provided with at least one second through hole penetrating through the second humidity-sensitive electrode.
According to another aspect of the present invention, there is also provided a humidity sensor comprising the humidity sensing structure of any of the above embodiments.
The utility model provides a humidity sensing structure and humidity transducer aim at with the base plate at first humidity sensitive electrode place with the base plate at second humidity sensitive electrode place separately to adopt the mode of flip-chip bonding will first base plate with fixed connection between the second base plate makes at least one sense wet dielectric layer with the parallel wet surface of sense of first base plate and second base plate and air direct contact for the speed that the hydrone spreads to the wet dielectric layer of sense, thereby improves the humidity transducer response speed who has this humidity sensing structure.
Furthermore, because the second substrate is a PCB substrate and an additional signal processing circuit structure can be added on the PCB substrate except for the electrode area, the moisture-sensitive electrode on one of the non-PCB substrates is electrically connected with the signal processing circuit structure in the PCB substrate during the bonding and fixing process of the first substrate and the second substrate, so that the transmission of electrical signals is realized, the processing and reading of sensor signals are more convenient, and the manufacturing cost is correspondingly reduced.
In addition, different from the traditional MEMS technology based on the silicon substrate, one of the electrodes is arranged on the PCB, so that the steps based on the silicon substrate chip flowing process are simplified, the manufacturing is easy, the risk of chip flowing is reduced, the dielectric constant of a sensor humidity sensing medium is met, meanwhile, the flip-chip bonding structure is adopted, on one hand, extra through holes and wiring are not needed to be manufactured, the connection is convenient, the process steps for manufacturing the humidity sensor are reduced, on the other hand, the redundant interconnection line length of the humidity sensor is avoided, and the adverse effect of interfering parasitic capacitance and inductance is reduced.
Drawings
In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings needed to be used in the description of the embodiments are briefly introduced below, and it is obvious that the drawings in the following description are only some embodiments of the present application, and it is obvious for those skilled in the art to obtain other embodiments based on these drawings without creative efforts.
Fig. 1 is a schematic cross-sectional view of a conventional humidity sensing structure.
Fig. 2 is a schematic top view of a humidity sensing structure according to an embodiment of the present invention.
Fig. 3 isbase:Sub>A schematic sectional view alongbase:Sub>A-base:Sub>A' direction in fig. 2.
FIG. 4 is a schematic top view of the substrate with the second humidity-sensitive electrode provided in the embodiment of the humidity sensing structure in FIG. 2.
FIG. 5 is a schematic top view of a substrate with a second humidity-sensitive electrode provided in an alternative embodiment of the humidity-sensing structure of FIG. 2.
Fig. 6 is a schematic cross-sectional view of a humidity sensing structure according to another embodiment of the present invention.
Fig. 7 is a schematic cross-sectional view of a humidity sensing structure according to another embodiment of the present invention.
Detailed Description
The foregoing description is only an overview of the technical solutions of the present invention, and in order to make the technical means of the present invention more clearly understood, the present invention may be implemented in accordance with the content of the description, and in order to make the above and other objects, features, and advantages of the present invention more clearly understood, the following preferred embodiments are specifically illustrated below, and the detailed description is given in conjunction with the accompanying drawings.
In the description of the present invention, it is to be noted that, unless otherwise explicitly specified or limited, the terms "mounted," "connected," and "connected" are to be construed broadly, and may be, for example, fixedly connected, detachably connected, or integrally connected; may be mechanically, electrically or may be in communication with each other; either directly or indirectly through intervening media, either internally or in any other relationship. The specific meaning of the above terms in the present invention can be understood according to specific situations by those skilled in the art.
In order to make the objects, features and advantages of the present invention more comprehensible, the present invention is described in detail with reference to the accompanying drawings and the detailed description.
Example one
Fig. 2 isbase:Sub>A schematic top view ofbase:Sub>A humidity sensing structure according to an embodiment of the present invention, fig. 3 isbase:Sub>A schematic cross-sectional view alongbase:Sub>A-base:Sub>A' direction in fig. 2, and fig. 4 isbase:Sub>A schematic top view ofbase:Sub>A substrate on whichbase:Sub>A second humidity sensitive electrode is disposed according to an embodiment of the humidity sensing structure in fig. 2.
As shown in fig. 2-4, the humidity sensing structure of the embodiment of the present invention includes: a first substrate 1 and a second substrate 6 disposed opposite to each other; a first humidity-sensitive electrode 4, said first humidity-sensitive electrode 4 being located on a side of said first substrate 1 facing said second substrate 6; a second humidity-sensitive electrode 2, the second humidity-sensitive electrode 2 being located on a side of the second substrate 6 facing the first substrate 1; at least one humidity sensitive dielectric layer 3, wherein the at least one humidity sensitive dielectric layer 3 is arranged between the first humidity sensitive electrode 4 and the second humidity sensitive electrode 2; wherein the humidity sensing surface of the at least one humidity sensing medium layer 3 parallel to the first substrate 1 and the second substrate 6 is in direct contact with air.
Wherein, the material of the first humidity sensitive electrode 4 and the second humidity sensitive electrode 2 can be metal or metal oxide such as aluminum, copper, gold, tantalum, chromium, etc.; preferably, for example, aluminum is selected, which not only has a low electrical conductivity, but also is relatively inexpensive. The material of the moisture-sensitive medium layer 3 is generally selected from organic materials, such as polyimide, or polyimide-based materials, in which the dielectric constant changes in response to humidity, and the polyimide-based materials are doped with conductive materials.
Illustratively, the first substrate 1 includes a silicon material or a silicon dioxide material, such as a silicon wafer or a glass substrate. The second substrate 6 includes a ceramic board or a PCB substrate, and illustratively, metal patterns and wiring structures may be formed in the PCB substrate according to a circuit design by using a conventional printed circuit board process, for example, a signal processing circuit structure, etc.
In this embodiment, the first humidity-sensitive electrode 4, the second humidity-sensitive electrode 2 and the humidity-sensitive medium layer 3 located between the first humidity-sensitive electrode 4 and the second humidity-sensitive electrode 2 form a humidity-sensitive capacitor, and the humidity sensor having the humidity sensing structure is designed to increase the speed of water molecules diffusing into the humidity-sensitive medium layer 3 by directly contacting the humidity-sensitive surface of at least one humidity-sensitive medium layer 3, which is parallel to the first substrate 1 and the second substrate 6, with air, so as to increase the response speed of the humidity sensor.
Along a direction perpendicular to the plane of the first substrate 1, projections of the first humidity sensitive electrode 4, the second humidity sensitive electrode 2 and the at least one humidity sensitive dielectric layer 3 at least partially overlap. The vertical electric field formed between the first humidity-sensitive electrode 4 and the second humidity-sensitive electrode 2 acts on the at least one humidity-sensitive dielectric layer 3, so that a corresponding electric signal can be generated according to the change of the humidity-sensitive capacitance between the first humidity-sensitive electrode 4 and the second humidity-sensitive electrode 2 to detect the humidity change in the environment to be detected.
Optionally, in this embodiment, the at least one humidity sensitive dielectric layer 3 includes only one humidity sensitive dielectric layer 3, the humidity sensitive dielectric layer 3 is located on a side of the first humidity sensitive electrode 4 facing away from the first substrate 1, and an air gap is formed between the humidity sensitive dielectric layer 3 and the second humidity sensitive electrode 2.
In this embodiment, the first substrate 1 is fixedly connected to the second substrate 6 by a bonding structure in a flip-chip manner. Specifically, the bonding structure includes: at least one first conductive bump 41, each first conductive bump 41 being located on a side of the first substrate 1 facing the second substrate 6; at least one second conductive bump 61, each second conductive bump 61 being located on a side of the second substrate 6 facing the first substrate 1; wherein the at least one first conductive bump 41 corresponds to and is bonded to the at least one second conductive bump 61 one to one, and a projection of each first conductive bump 41 overlaps a projection of each second conductive bump 61 on a plane perpendicular to the first substrate 1. Each of the first conductive bumps 41 is bonded to each of the second conductive bumps 61 through a conductive solder ball 7.
For example, the material of the first conductive bump 41 and the second conductive bump 61 may be metal or metal oxide such as aluminum, copper, gold, tantalum, chromium, etc.; preferably, for example, aluminum is selected, which not only has a low electrical conductivity, but also is relatively inexpensive. Specifically, the first conductive bump 41 and the first humidity-sensitive electrode 4 may be formed on the same layer by a photolithography process, and the second conductive bump 61 and the second humidity-sensitive electrode 2 may be formed on the same layer by a photolithography process.
It should be noted that, in the embodiment, it is intended to separate the substrate on which the first humidity-sensitive electrode 4 is located from the substrate on which the second humidity-sensitive electrode 2 is located, fixedly connect the first substrate 1 and the second substrate 6 through a bonding structure in a flip-chip bonding manner, and correspondingly control the distance between the first substrate 1 and the second substrate 6 according to the thickness of the bonding structure, so that an air gap is formed between the humidity-sensitive medium layer 3 and the second humidity-sensitive electrode 2, thereby avoiding the close contact between the humidity-sensitive medium layer 3 and the first humidity-sensitive electrode 4 and the second humidity-sensitive electrode 2, providing a favorable space for the diffusion of water vapor molecules, increasing the diffusion speed of water molecules to the humidity-sensitive medium layer 3, and further increasing the response speed of the humidity sensor with the humidity-sensitive structure.
Preferably, the first humidity-sensitive electrode 4 is located at a central region of the first substrate 1, and the second humidity-sensitive electrode 2 is located at a central region of the second substrate 6.
Alternatively, as shown in fig. 4, the at least one second conductive bump 61 is uniformly arranged around the second humidity-sensitive electrode 2, and the second conductive bumps 61 correspond to the first conductive bumps 41 one by one and form a bonding structure for supporting and fixing the first substrate 1 and the second substrate 6. It should be understood that, in the present embodiment, the number, the position and the size of the first conductive bumps 41 and the second conductive bumps 61 can be set according to actual requirements.
The first humidity-sensitive electrode 4 is electrically connected with each corresponding first conductive bump 41 through a trace and is led to the through hole electrical connection structure 8', and the second humidity-sensitive electrode 2 is electrically connected with the corresponding through hole electrical connection structure 8 through a trace.
Continuing to refer to fig. 4, exemplarily, two through hole electrical connection structures (8, 8 ') are further disposed on the second substrate 6, wherein one of the through hole electrical connection structures 8 is electrically connected to the second humidity sensitive electrode 2 directly by a trace, the other through hole electrical connection structure 8' is electrically connected to the second conductive bump 61 by a trace, and the second conductive bump 61 is electrically connected to the first conductive bump 41. In this embodiment, since the second substrate 6 is a PCB substrate, a metal pattern and a wiring structure can be manufactured in the PCB substrate by using a conventional printed circuit board process, the second humidity-sensitive electrode 2 is connected to the through hole electrical connection structure 8 through a wire, and the through hole electrical connection structure 8 is electrically connected to a signal circuit structure in the PCB substrate, so that a second voltage signal is applied to the second humidity-sensitive electrode 2 through the second substrate 6 (PCB substrate). The other through hole electrical connection structure 8 'is electrically connected with a signal circuit structure in the PCB substrate, the other through hole electrical connection structure 8' is electrically connected with the second conductive bump 61 through a trace, the second conductive bump 61 is electrically connected with the first conductive bump 41, and the first conductive bump 41 is electrically connected with the first humidity-sensitive electrode 4, so that a first voltage signal is applied to the first humidity-sensitive electrode 4 through the second substrate 6 (PCB substrate). It should be understood that at least one of the second electrical bumps 61 may be electrically connected to the corresponding first conductive bump 41.
Wherein the area of the sensing region of the humidity sensing structure is in direct proportion to the sensitivity, so that the projection of the first humidity sensitive electrode 4 and/or the second humidity sensitive electrode 2 is located within the projection of the at least one humidity sensitive medium layer 3 along the direction perpendicular to the plane where the first substrate 1 and the second substrate 6 are located. That is, the projection of the at least one wetness sensitive medium layer 3 is larger than the projection of the first wetness sensitive electrode 4 and/or the second wetness sensitive electrode 2 to increase the area of the sensing area of the wetness sensing structure.
Further, the humidity sensing structure further comprises an insulating medium layer 5; wherein, in the case that the humidity sensitive dielectric layer 3 is located on the side of the first humidity sensitive electrode 4 facing away from the first substrate 1, the insulating dielectric layer 5 is arranged between the humidity sensitive dielectric layer 3 and the first humidity sensitive electrode 4 along the direction perpendicular to the plane of the first substrate 1. The insulating dielectric layer 5 may be a non-metallic material, such as silicon oxide or silicon oxynitride. The insulating medium layer 5 can isolate the corrosion of moisture to the first humidity-sensitive electrode 4, thereby prolonging the service life and accuracy of the humidity sensor.
FIG. 5 is a schematic top view of a substrate with a second humidity-sensitive electrode provided in an alternative embodiment of the humidity-sensing structure of FIG. 2.
As shown in fig. 5, in order to further improve the air permeability of the humidity sensor and facilitate the desorption of water vapor, at least one second through hole 21 penetrating the second humidity-sensitive electrode 2 is further formed on the second substrate 6.
It should be understood that at least one first through hole penetrating through the first humidity-sensitive electrode 4 may also be disposed on the first substrate 1, so as to improve the air permeability of the humidity sensor and facilitate the desorption of water vapor.
Example two
Fig. 6 is a schematic cross-sectional view of a humidity sensing structure according to another embodiment of the present invention.
As shown in fig. 6, fig. 6 differs from fig. 3 exemplarily in that: in fig. 6, the humidity sensitive dielectric layer 3 is located on the side of the second humidity sensitive electrode 2 facing away from the second substrate 6 and there is an air gap between the humidity sensitive dielectric layer 3 and the first humidity sensitive electrode 4.
Similarly, in the present embodiment, the first substrate 1 is fixedly connected to the second substrate 6 by a bonding structure in a flip-chip manner. The substrate where the first humidity-sensitive electrode 4 is located is separated from the substrate where the second humidity-sensitive electrode 2 is located, the first substrate 1 and the second substrate 6 are fixedly connected through the bonding structure in a flip-chip bonding mode, and the distance between the first substrate 1 and the second substrate 6 is correspondingly controlled according to the thickness of the bonding structure, so that an air gap is formed between the humidity-sensitive medium layer 3 and the first humidity-sensitive electrode 4, so that the close contact between the humidity-sensitive medium layer 3 and the first humidity-sensitive electrode 4 as well as the second humidity-sensitive electrode 2 is avoided, a favorable space is provided for the diffusion of water vapor molecules, the speed of water molecules diffusing to the humidity-sensitive medium layer 3 is increased, and the response speed of the humidity sensor with the humidity-sensitive structure is further increased.
In particular, the bonding structure comprises at least one first conductive bump 41, each first conductive bump 41 being located on a side of the first substrate 1 facing the second substrate 6; at least one second conductive bump 61, each second conductive bump 61 being located on a side of the second substrate 6 facing the first substrate 1; wherein the at least one first conductive bump 41 corresponds to and is bonded to the at least one second conductive bump 61 one to one, and a projection of each first conductive bump 41 overlaps a projection of each second conductive bump 61 on a plane perpendicular to the first substrate 1. Each of the first conductive bumps 41 is bonded to each of the second conductive bumps 61 through a conductive solder ball 7. It should be understood that at least one of the first conductive bumps 41 and the corresponding second conductive bump 61 may be bonded and connected through the conductive solder ball 7.
Further, the humidity sensing structure further comprises an insulating medium layer 5; wherein, in the case that the humidity sensitive medium layer 3 is located on the side of the second humidity sensitive electrode 2 facing away from the second substrate 6, the insulating medium layer 5 is arranged between the humidity sensitive medium layer 3 and the second humidity sensitive electrode 2 along the direction perpendicular to the plane of the second substrate 6. The insulating dielectric layer 5 may be a non-metallic material, such as silicon oxide or silicon oxynitride. The insulating medium layer 5 can isolate the corrosion of moisture to the second humidity sensitive electrode 2, thereby prolonging the service life and the accuracy of the humidity sensor.
EXAMPLE III
Fig. 7 is a schematic cross-sectional view of a humidity sensing structure according to another embodiment of the present invention.
As shown in fig. 7, fig. 7 differs from fig. 3 exemplarily in that: in fig. 7, the at least one moisture-sensitive medium layer 3 includes a first moisture-sensitive medium layer 31 and a second moisture-sensitive medium layer 32; wherein the first humidity sensitive medium layer 31 is located on a side of the first humidity sensitive electrode 4 facing away from the first substrate 1, the second humidity sensitive medium layer 32 is located on a side of the second humidity sensitive electrode 2 facing away from the second substrate 6, and an air gap is formed between the first humidity sensitive medium layer 31 and the second humidity sensitive medium layer 32.
In this embodiment, the first substrate 1 is fixedly connected to the second substrate 6 by a bonding structure in a flip-chip manner. The substrate (polar plate) where the first humidity sensitive electrode 4 is located is separated from the substrate (polar plate) where the second humidity sensitive electrode 2 is located, the first substrate 1 and the second substrate 6 are fixedly connected through the bonding structure in a flip-chip bonding mode, and the distance between the first substrate 1 and the second substrate 6 is correspondingly controlled according to the thickness of the bonding structure, so that an air gap is formed between the first humidity sensitive medium layer 3 and the second humidity sensitive electrode 2, thereby avoiding the close contact of the humidity sensitive medium layer 3 with the first humidity sensitive electrode 4 and the second humidity sensitive electrode 2, providing a favorable space for the diffusion of water vapor molecules, accelerating the diffusion of the water molecules to the humidity sensitive medium layer 3, and further improving the response speed of the humidity sensor with the humidity sensing structure.
Specifically, the bonding structure includes at least one first conductive bump 41, each first conductive bump 41 being located on a side of the first substrate 1 facing the second substrate 6; at least one second conductive bump 61, each second conductive bump 61 being located on a side of the second substrate 6 facing the first substrate 1; wherein the at least one first conductive bump 41 corresponds to and is bonded to the at least one second conductive bump 61 one to one, and a projection of each first conductive bump 41 overlaps a projection of each second conductive bump 61 on a plane perpendicular to the first substrate 1. Each of the first conductive bumps 41 and each of the second conductive bumps 61 can be bonded by at least one conductive solder ball 7, or in other embodiments, the thickness of the first conductive bumps 41 and each of the second conductive bumps 61 corresponding to each of the first conductive bumps 41 can be correspondingly increased, which is not limited herein.
Further, the humidity sensing structure further includes a first insulating medium layer 51 and a second insulating medium layer 52; in a direction perpendicular to the plane of the first substrate 1 and the second substrate 6, the first insulating medium layer 51 is located between the first humidity sensitive medium layer 31 and the first humidity sensitive electrode 4, and the second insulating medium layer 52 is located between the second humidity sensitive medium layer 32 and the second humidity sensitive electrode 2. The first insulating dielectric layer 51 and the second insulating dielectric layer 52 may be made of a non-metal material, such as silicon oxide or silicon oxynitride. The first insulating medium layer 51 and the second insulating medium layer 52 are arranged to isolate the first humidity-sensitive electrode 4 and the second humidity-sensitive electrode 2 from moisture, so as to prolong the service life and accuracy of the humidity sensor.
The utility model also provides a humidity transducer, humidity transducer includes as above any kind of humidity sensing structure.
Therefore, adopt the embodiment of the utility model provides a humidity sensing structure and humidity transducer aims at separating the base plate (polar plate) that first humidity sensitive electrode place and the base plate (polar plate) that the second humidity sensitive electrode place to adopt flip-chip bonding's mode will first base plate with fixed connection between the second base plate, make at least one humidity sensitive dielectric layer with the humidity sensitive surface and the air direct contact that first base plate and second base plate are parallel for the speed that the hydrone spreads to humidity sensitive dielectric layer, thereby improve the humidity transducer response speed who has this humidity sensing structure.
Furthermore, because the second substrate is a PCB substrate and an additional signal processing circuit structure can be added on the PCB substrate except for the electrode area, the moisture-sensitive electrode on one of the non-PCB substrates is electrically connected with the signal processing circuit structure in the PCB substrate during the bonding and fixing process of the first substrate and the second substrate, so that the transmission of electric signals is realized, the processing and reading of sensor signals are facilitated, and the manufacturing cost is correspondingly reduced.
In addition, be different from traditional MEMS technology based on the silicon substrate, set up one of them electrode on the PCB board, thereby simplified the step based on silicon substrate tape-out process, easily preparation has reduced the risk of tape-out, when satisfying the dielectric constant of sensor humidity-sensing medium, adopt the structure of flip-chip bonding, do not need additionally to make through-hole and wiring on the one hand, convenient connection has reduced the process steps of preparation humidity transducer, on the other hand has avoided the unnecessary interconnect line length of humidity transducer, thereby reduced the harmful effects of disturbing parasitic capacitance inductance.
Finally, it should be noted that: the above embodiments are only used to illustrate the technical solution of the present invention, and not to limit it; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art will understand that: the technical solutions described in the foregoing embodiments may still be modified, or some technical features may be equivalently replaced; such modifications and substitutions do not depart from the spirit and scope of the present invention in its corresponding aspects.
Claims (14)
1. A humidity sensing structure, comprising:
the first substrate and the second substrate are oppositely arranged;
a first humidity-sensitive electrode located on a side of the first substrate facing the second substrate;
a second humidity-sensitive electrode on a side of the second substrate facing the first substrate;
at least one moisture sensitive dielectric layer disposed between the first moisture sensitive electrode and the second moisture sensitive electrode;
a humidity-sensitive surface of the at least one humidity-sensitive dielectric layer parallel to the first substrate and the second substrate is in direct contact with air;
the second substrate is a PCB substrate.
2. The humidity sensing structure of claim 1,
along the direction perpendicular to the plane of the first substrate, the projections of the first humidity-sensitive electrode, the second humidity-sensitive electrode and the at least one humidity-sensitive medium layer are at least partially overlapped.
3. The humidity sensing structure of claim 2,
the at least one humidity-sensitive dielectric layer comprises only one humidity-sensitive dielectric layer which is located on the side of the first humidity-sensitive electrode facing away from the first substrate and has an air gap with the second humidity-sensitive electrode, or the humidity-sensitive dielectric layer is located on the side of the second humidity-sensitive electrode facing away from the second substrate and has an air gap with the first humidity-sensitive electrode.
4. The humidity sensing structure according to claim 3,
comprises an insulating medium layer;
the humidity sensing medium layer is located under the condition that the first humidity sensitive electrode deviates from one side of the first substrate, the first substrate is perpendicular to the plane direction of the first substrate, the insulating medium layer is arranged between the humidity sensing medium layer and the first humidity sensitive electrode, or the humidity sensing medium layer is located under the condition that the second humidity sensitive electrode deviates from one side of the second substrate, the second substrate is perpendicular to the plane direction of the second substrate, and the insulating medium layer is arranged between the humidity sensing medium layer and the second humidity sensitive electrode.
5. The humidity sensing structure according to claim 2,
the at least one moisture sensitive media layer comprises a first moisture sensitive media layer and a second moisture sensitive media layer;
the first humidity sensitive dielectric layer is located on one side, away from the first substrate, of the first humidity sensitive electrode, the second humidity sensitive dielectric layer is located on one side, away from the second substrate, of the second humidity sensitive electrode, and an air gap is formed between the first humidity sensitive dielectric layer and the second humidity sensitive dielectric layer.
6. The humidity sensing structure of claim 5,
the insulating structure comprises a first insulating medium layer and a second insulating medium layer;
the first insulating medium layer is positioned between the first humidity sensitive medium layer and the first humidity sensitive electrode, and the second insulating medium layer is positioned between the second humidity sensitive medium layer and the second humidity sensitive electrode along the direction perpendicular to the plane where the first substrate and the second substrate are positioned.
7. The humidity sensing structure of claim 2,
the first substrate and the second substrate are fixedly connected through a bonding structure.
8. The humidity sensing structure of claim 7, wherein the bonding structure comprises:
at least one first conductive bump, each first conductive bump being located on a side of the first substrate facing the second substrate;
at least one second conductive bump, each second conductive bump being located on a side of the second substrate facing the first substrate;
the at least one first conductive bump and the at least one second conductive bump are in one-to-one correspondence and are bonded, and in a plane perpendicular to the first substrate, the projection of each first conductive bump is overlapped with the projection of each second conductive bump.
9. The humidity sensing structure of claim 8,
and each first conductive bump is bonded with each corresponding second conductive bump through a conductive solder ball.
10. The humidity sensing structure according to claim 9,
the first humidity sensitive electrodes are electrically connected with each corresponding first conductive bump through wiring, and the second humidity sensitive electrodes are electrically connected with the corresponding through hole electrical connection structures through wiring.
11. The humidity sensing structure of claim 10,
two through hole electric connection structures are arranged on the second substrate, wherein one through hole electric connection structure is electrically connected with the second humidity sensitive electrode through a wiring, and the other through hole electric connection structure is electrically connected with the second conductive bump through a wiring.
12. The humidity sensing structure of claim 2,
and the projection of the first humidity-sensitive electrode and/or the second humidity-sensitive electrode is positioned in the projection of the at least one humidity-sensitive medium layer along the direction vertical to the plane where the first substrate and the second substrate are positioned.
13. The humidity sensing structure of claim 2,
the first substrate is provided with at least one first through hole penetrating through the first humidity-sensitive electrode, and/or the second substrate is further provided with at least one second through hole penetrating through the second humidity-sensitive electrode.
14. A humidity sensor comprising a humidity sensing structure according to any one of claims 1 to 13.
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