Patent Description:
Sensors generally refer to components that output signals according to physical, chemical or environmental changes, such as resistive sensors, piezoelectric sensors, pyroelectric sensors, electrochemical sensors, and microwave sensors. In the aforementioned sensors, some sensors need to form a cavity structure based on the consideration of sensing principle.

As disclosed in the U. S Patent No. <CIT>, a pressure sensor comprises a cavity formed by a molding material, a control die disposed in the cavity, and a pressure transducer die disposed on the control die, the control die and the pressure transducer die are connected to each other through a wire bonding, and then the dies are adhered on a carrier baseplate through dispensing an adhesive.

S Patent Publication No. <CIT> discloses an ultrasonic device comprising an ultrasonic transducer and an inlet hole, the ultrasonic transducer comprises a base and a membrane, wherein the base and the membrane are disposed with a sealed cavity formed between the base and the membrane, the inlet hole penetrates the membrane, and the inlet hole is configured as a passage for entering into the sealed cavity.

<CIT> relates to infrared detecting elements.

For the above-mentioned sensor or transducer provided with a cavity structure, an adhesive is usually used to fix the cavity structure on the carrier baseplate for subsequent packaging processes. In practice, the adhesive is usually a die-bonding adhesive. However, when the adhesive is used for fixing, the cavity structure is likely to be sealed due to too many glue spots being formed by the adhesive, which will easily cause the sensor to be damaged during the operation; on the other hand, if too few glue spots are formed by the adhesive, it will easily cause the joint surfaces to fall off.

A main object of the invention is to solve the problem that conventional sensors with a cavity are easily damaged or fall off easily due to the use of adhesive.

In order to achieve the above-mentioned object, the invention provides a sensor with a chamber according to claim <NUM>.

In order to achieve the above-mentioned object, the invention further provides a sensor with a chamber comprising a base, a cavity body, a sensing element, and a porous gel material. The cavity body is disposed on the base and includes a cavity wall and an inner space formed therein, the sensing element is disposed on a top wall of the cavity body, and the porous gel material is partially disposed in the inner space. Furthermore, the porous gel material includes a first surface covered by the cavity wall without exposing to an outside and a second surface exposed to the outside without covering by the cavity wall, wherein a porosity of the porous gel material is not less than <NUM>%, so that gas is capable of communicating between the inner space of the cavity body and the outside through the second surface.

The invention integrates the porous gel material into the sensor, and the porous gel material serves as a passage for gas communicating with the outside. Since gas is capable of entering and exiting between the inner space and the outside, an air pressure between the inner space and the outside can be balanced, and glue spots of an adhesive can be thoroughly set, and the integrity of sensing function can still be met without sacrificing a degree of bonding. In addition, the cavity body can be filled with the porous gel material, so that the cavity body is supportive and not easily damaged, and heat loss in the inner space can be reduced.

The detailed description and technical contents of the invention are described below with reference to the drawings.

Please refer to <FIG>, the invention provides a sensor with a chamber, which comprises a base <NUM>, a cavity body <NUM>, a sensing element <NUM>, a porous gel material <NUM>, and an attach layer <NUM>. In the invention, the sensor with the chamber can be any sensor with a chamber structure. According to different usage requirements, the sensor with the chamber can be selected as a temperature sensor, a gas sensor, a pressure sensor, a tire pressure gauge, or a microphone. In the invention, a material of the base <NUM> can be metal, glass, ceramic, polymer, or composite materials thereof. For example, the base <NUM> can be silicon wafer, plastic, printed circuit board (PCB), fiberglass plate, silicon dioxide, or photoresist.

The cavity body <NUM> is disposed on the base <NUM>. The cavity body <NUM> comprises a cavity wall <NUM> and an inner space <NUM>, the inner space <NUM> is formed inside the cavity wall <NUM>. The cavity wall <NUM> comprises a side wall <NUM> and a top wall <NUM> disposed thereon, and the sensing element <NUM> is disposed on the top wall <NUM>. In this embodiment, the side wall <NUM> is made of a silicon material, and the top wall <NUM> is made of an insulating material. The porous gel material <NUM> is disposed between the base <NUM> and the cavity body <NUM>. The porous gel material <NUM> includes a specific surface area between <NUM><NUM>/g and <NUM><NUM>/g, and a porosity greater than <NUM>%. In one embodiment, the porosity is between <NUM>% and <NUM>%, the porous gel material <NUM> includes a density between <NUM>/cm<NUM> and <NUM>/cm<NUM> , and a thermal conductivity value lower than <NUM> W/m-K. The porous gel material <NUM> can be a silicon-based material or a hydrophobic material, wherein the silicon-based material is selected from a group consisting of silicon-based compounds such as siloxane compounds, water glass and sodium silicate, for example, the porous gel material <NUM> comprises a silicon-based compound and an additive mixed with the silicon-based compound. The additive is selected from a group consisting of single-layer carbon nanotubes, multilayer carbon nanotubes, multilayer graphene, and combinations thereof. Thereby, gas can easily pass through the inner space <NUM> of the cavity body <NUM> by using the porosity of the porous gel material <NUM>, and flow in and out between the inner space <NUM> and an outside <NUM> in order to balance an air pressure inside the sensor with the chamber.

The attach layer <NUM> comprises a first attach layer <NUM> and a second attach layer <NUM>. The first attach layer <NUM> is attached between the porous gel material <NUM> and the base <NUM>, the second attach layer <NUM> is attached between the cavity body <NUM> and the porous gel material <NUM>, and the porous gel material <NUM> and the attach layer <NUM> can be different structures such as the shape of the layer or the shape of the ring, respectively. Wherein the attach layer <NUM> is selected from adhesive tape, adhesive film, wafer attach film, die attach film, FOD (Fingerprint On Display) film, FOW (Film Over Wire) film, die-bonding adhesive, or other adhering materials.

<FIG> and <FIG> are different aspects of a first embodiment of the invention, respectively; and <FIG>, <FIG> are different aspects of a second embodiment of the invention, respectively.

As shown in <FIG>, in a first mode of the first embodiment of the invention, the porous gel material <NUM> is into a shape of a layer or a sheet, and the layer extends from one side to the other side of the side wall <NUM> of the cavity body <NUM>; the first attach layer <NUM> is into a shape of a layer or a sheet, and the layer extends from one side to the other side of the side wall <NUM> of the cavity body <NUM>, in other words, two-dimensional geometric shapes of the porous gel material <NUM> and the first attach layer <NUM> correspond to each other on the XY plane; the second attach layer <NUM> is disposed between the porous gel material <NUM> and the side wall <NUM>, and is into a shape of ring corresponding to the side wall <NUM>, and two-dimensional geometric shapes of the second attach layer <NUM> and the side wall <NUM> correspond to each other on the XY plane. Gas is capable of exiting from or entering into the cavity body <NUM> as shown by arrows in <FIG>. As shown in <FIG>, in a second mode of the first embodiment of the invention, both the porous gel material <NUM> and the first attach layer <NUM> are into a shape of a layer or a sheet, and correspond to a two-dimensional geometric shape of the base <NUM> on the XY plane; the second attach layer <NUM> is disposed between the porous gel material <NUM> and the side wall <NUM>, and the second attach layer <NUM> is into a shape of a ring corresponding to the side wall <NUM>, and two-dimensional geometric shapes of the second attach layer <NUM> and the side wall <NUM> correspond to each other on the XY plane. Gas is capable of exiting from or entering into the cavity body <NUM> as shown by arrows in <FIG>. As shown in <FIG>, in a third mode of the first embodiment of the invention, the porous gel material <NUM>, the first attach layer <NUM>, and the second attach layer <NUM> are all into a shape of a ring corresponding to a two-dimensional geometric shape of the side wall <NUM> on the XY plane. Gas is capable of exiting from or entering into the cavity body <NUM> as shown by arrows in <FIG>.

As shown in <FIG>, in a first mode of the second embodiment of the invention, the porous gel material <NUM> comprises a first portion <NUM> and a second portion <NUM>, the first portion <NUM> is disposed in the inner space <NUM>, the second portion <NUM> is disposed between the base <NUM> and the cavity body <NUM>. The first portion <NUM> includes a first surface <NUM>, the second portion <NUM> includes a second surface <NUM>, the first surface <NUM> is covered without exposing to the outside <NUM>, and the second surface <NUM> is exposed to the outside <NUM> without covering. In this embodiment, the second portion <NUM> of the porous gel material <NUM> is into a shape of a layer or a sheet, and the layer extends from one side to the other side of the side wall <NUM> of the cavity body <NUM>; the first attach layer <NUM> is into a shape of a layer or a sheet, and the layer extends from one side to the other side of the side wall <NUM> of the cavity body <NUM>, in other words, two-dimensional geometric shapes of the second portion <NUM> of the porous gel material <NUM> and the first attach layer <NUM> correspond to each other on the XY plane; the second attach layer <NUM> is disposed between the second portion <NUM> of the porous gel material <NUM> and the side wall <NUM>, and the second attach layer <NUM> is into a shape of a ring corresponding to the side wall <NUM>, and two-dimensional geometric shapes of the second attach layer <NUM> and the side wall <NUM> correspond to each other on the XY plane. In this embodiment, the first surface <NUM> of the first portion <NUM> is covered by the side wall <NUM>, the top wall <NUM>, the second attach layer <NUM> and the second portion <NUM> without directly communicating with the outside <NUM>, the second surface <NUM> (i.e., an outer side) of the second portion <NUM> is not covered, and the first portion <NUM> and the second portion <NUM> are connected with each other so that gas is capable of exiting from or entering into the cavity body <NUM> as shown by arrows in <FIG>. As shown in <FIG>, in a second mode of the second embodiment of the invention, both the second portion <NUM> of the porous gel material <NUM> and the first attach layer <NUM> are into a shape of a layer or a sheet, and correspond to a two-dimensional geometric shape of the base <NUM> on the XY plane; the second attach layer <NUM> is disposed between the second portion <NUM> of the porous gel material <NUM> and the side wall <NUM>, the second attach layer <NUM> is into a shape of a ring corresponding to the side wall <NUM>, and two-dimensional geometric shapes of the second attach layer <NUM> and the side wall <NUM> correspond to each other on the XY plane. Gas is capable of exiting from or entering into the cavity body <NUM> as shown by arrows in <FIG>. As shown in <FIG>, in a third mode of the second embodiment of the invention, the porous gel material <NUM> is disposed in the inner space <NUM>, and a height h1 of the porous gel material <NUM> is greater than a height h2 of the side wall <NUM>, so that the porous gel material <NUM> is formed with the first surface <NUM> that is covered without exposing to the outside <NUM>, and the second surface <NUM> is exposed to the outside <NUM> without covering, and the attach layer <NUM> is disposed between the porous gel material <NUM> and the base <NUM> to fix the porous gel material <NUM>. Gas is capable of exiting from or entering into the cavity body <NUM> as shown by arrows in <FIG>.

Claim 1:
A sensor with a chamber comprising:
a base (<NUM>);
a cavity body (<NUM>), disposed on the base (<NUM>) and comprising a cavity wall (<NUM>) and an inner space (<NUM>) formed therein;
a sensing element (<NUM>), disposed on the cavity wall (<NUM>); and
a porous gel material (<NUM>), attached between the base (<NUM>) and the cavity body (<NUM>),
characterized in that a porosity of the porous gel material (<NUM>) is not less than <NUM>%, the porous gel material (<NUM>) comprises a first surface (<NUM>) covered by the cavity wall (<NUM>) so that it is not exposed to an outside (<NUM>), and a second surface (<NUM>) exposed to the outside (<NUM>) to enable a gas to communicate between the inner space (<NUM>) of the cavity body (<NUM>) and the outside (<NUM>), wherein the porous gel material (<NUM>) comprises a silicon-based compound and an additive mixed with the silicon-based compound, the additive is selected from a group consisting of single-layer carbon nanotubes, multilayer carbon nanotubes, multilayer graphene, and combinations thereof.