Pressure sensor and method of manufacturing the same

Abstract

The present application provides a pressure sensor and a manufacturing method thereof. The pressure sensor comprises a support substrate and a resistance substrate on the support substrate. The support substrate comprises a base material and a patterned support layer on the base material. The resistance substrate comprises a wave-shaped base material, a wire portion and a resistance portion. The wave-shaped base material has a wave surface and a back surface opposite to the wave surface, wherein the wave surface comprises a wave peak area and a wave valley area. The distance between the back surface and the wave peak area is smaller than the distance between the back surface and the wave valley area. The wire portion and the resistance portion are arranged on the wave surface of the wave-shaped base material in a staggered manner. The pressure sensor of the present application generates corresponding deformation amounts under different pressures through the resistance portion, which helps to improve the working pressure range of the pressure sensor.

Description

Technical Field

[0001] This invention relates to a pressure sensor and a method for manufacturing the same, and more particularly to a resistive pressure sensor and a method for manufacturing the same. Background Technology

[0002] Pressure sensors are widely used in consumer electronics, automotive electronics, industrial electronics, and biomedical health monitoring. For example, automotive applications include tire pressure monitoring systems, which monitor tire pressure to reduce traffic accidents. Generally, pressure sensors can be classified into three types based on their sensing principle: capacitive, piezoresistive, and piezoelectric. Taking a resistive pressure sensor as an example, when an external force deforms the diaphragm, the diaphragm's resistance changes due to the piezoresistive effect, and the sensor can detect the pressure from this change in resistance. Summary of the Invention

[0003] One aspect of the present invention is to provide a pressure sensor comprising a support substrate and a resistive substrate including a corrugated substrate.

[0004] Another aspect of the present invention is to provide a method for manufacturing a pressure sensor.

[0005] According to one aspect of the present invention, a pressure sensor is provided, comprising a support substrate and a resistive substrate. The support substrate includes a substrate and a patterned support layer disposed on the substrate. The resistive substrate is disposed on the support substrate. The resistive substrate includes a corrugated substrate having a corrugated surface and a back surface opposite the corrugated surface. The corrugated surface includes a plurality of crest regions and a plurality of trough regions, which are alternately arranged. The distance between the back surface and the crest regions is less than the distance between the back surface and the trough regions. The corrugated surface of the corrugated substrate faces the patterned support layer. The resistive substrate further includes a plurality of conductive portions and a plurality of resistive portions disposed on the corrugated surface of the corrugated substrate, wherein the plurality of conductive portions and the plurality of resistive portions are alternately arranged.

[0006] According to one embodiment of the present invention, the plurality of resistive portions include a plurality of first resistors and a plurality of second resistors. The first resistors are disposed in the trough region of the corrugated substrate, and the second resistors are disposed in the crest region of the corrugated substrate.

[0007] According to one embodiment of the present invention, the patterned support layer is located below the plurality of first resistors.

[0008] According to one embodiment of the present invention, the support layer is not located below the plurality of second resistors.

[0009] According to one embodiment of the present invention, the pressure sensor further includes an air gap disposed between the resistive substrate and the support substrate.

[0010] According to one embodiment of the present invention, the pressure sensor further includes an insulating substrate disposed on the back side of the corrugated substrate.

[0011] According to an embodiment of the present invention, the pressure sensor further includes a first protective layer covering the substrate and the patterned support layer, and a second protective layer covering the plurality of wire portions and the plurality of resistive portions.

[0012] According to one embodiment of the present invention, each of the plurality of resistor portions has a serpentine pattern or a linear pattern.

[0013] According to one embodiment of the present invention, the materials of the plurality of resistive portions include nano-silver, nano-copper, and nano-carbon nanotubes.

[0014] According to another aspect of the present invention, a method for manufacturing a pressure sensor is provided, comprising providing a support substrate. The support substrate includes a first substrate and a support layer on the first substrate. The method includes patterning a second substrate to give the second substrate a corrugated surface and a back surface opposite the corrugated surface, wherein the second substrate includes a plurality of crest segments and a plurality of trough segments, the crest segments and the trough segments being alternately arranged. The method includes forming a conductive layer on the corrugated surface of the second substrate; patterning the conductive layer to form a plurality of conductive wire portions; bonding a plurality of resistive portions to the conductive wire portions to obtain a resistive substrate; and bonding the support substrate to the resistive substrate. The distance between the support substrate and the crest segments is smaller than the distance between the support substrate and the trough segments.

[0015] According to one embodiment of the present invention, after providing the support substrate, the method further includes forming a photoresist layer on the support layer; and using the photoresist layer to pattern the support layer.

[0016] According to one embodiment of the present invention, the method further includes forming a cover film on the surface of the support substrate to cover the first substrate and the support layer.

[0017] According to one embodiment of the present invention, before patterning the second substrate, the method further includes providing a substrate stack, wherein the substrate stack includes the second substrate and a third substrate, and the third substrate is disposed on the back side of the second substrate.

[0018] According to one embodiment of the present invention, the method further includes forming a protective film on the plurality of resistive portions and the conductive portions.

[0019] According to one embodiment of the present invention, patterning the conductive layer includes removing portions of the conductive layer in the peak and trough regions of the second substrate.

[0020] The pressure sensor and its manufacturing method of the present invention can generate corresponding deformation under different pressures through multiple resistive parts, which helps to improve the working pressure range of the pressure sensor and reduce the requirement for material sensitivity coefficient. Attached Figure Description

[0021] A better understanding of the present invention will be obtained by reading the following detailed description in conjunction with the accompanying drawings. It should be noted that, as is standard practice in the industry, many features are not drawn to scale. In fact, for clarity of discussion, the dimensions of many features may be arbitrarily scaled.

[0022] Figure 1 A cross-sectional view of a pressure sensor according to some embodiments of the present invention is shown.

[0023] Figures 2A to 2D A cross-sectional view of an intermediate stage of the manufacturing process of a support substrate according to some embodiments of the present invention is shown.

[0024] Figures 3A to 3E A cross-sectional view illustrating an intermediate stage of the manufacturing process of a resistor substrate according to some embodiments of the present invention is shown.

[0025] Figure 4 A planar projection diagram of a pressure sensor according to some embodiments of the present invention is shown.

[0026] Figure 5 A graph illustrating the relationship between the resistance value of a pressure sensor and pressure changes according to some embodiments of the present invention is shown. Detailed Implementation

[0027] This invention provides numerous different embodiments or illustrations to implement various features of the invention. The specific examples of components and configurations described below are for the purpose of simplifying the invention. These are, of course, merely illustrative and are not intended to be limiting. For example, a description of a first feature formed on or above a second feature includes embodiments where the first and second features are in direct contact, as well as embodiments where other features are formed between the first and second features such that the first and second features are not in direct contact. Furthermore, the invention repeats element symbols and / or letters in various specific examples. This repetition is for the purpose of simplifying and clarifying the description and does not imply a relationship between the various discussed embodiments and / or configurations.

[0028] Furthermore, spatially relative terms, such as "below," "below," "lower," "above," and "upper," are used to facilitate the description of the relationship between a part or feature depicted in the accompanying drawings and other parts or features. In addition to the directions depicted in the drawings, spatially relative terms also include different orientations of the elements during use or operation. The device may be oriented in other ways (rotated 90 degrees or in other orientations), and the spatially relative descriptions used in this invention can also be interpreted in this way.

[0029] Generally, the principle of commonly used resistive pressure sensors is that the resistive layer deforms when an external force is applied, causing a change in resistance. According to the Wheatstone bridge circuit, the relationship between the resistance change (voltage change) and the deformation can be obtained. Then, the deformation is converted into a pressure value, and the relationship between the voltage change and the pressure value can be obtained. In other words, the pressure value can be obtained by detecting the voltage change using the following equations (1) and (2).

[0030] ΔR / R=GF×ε (1)

[0031] ε=P / E (2)

[0032] In equation (1), R represents resistance, ΔR represents the change in resistance, GF represents the material's sensitivity coefficient (or strain factor), and ε represents deformation. The deformation can be obtained through equation (2), where P represents pressure and E represents the elastic modulus.

[0033] As described above, the sensitivity of existing pressure sensors depends on the GF value. Especially when the deformation or pressure is small, materials with a large GF value are required to detect small pressure changes and accurately monitor changes in resistance. Furthermore, due to the limited deformation of planar resistor designs, they are unsuitable for detecting larger pressures. Therefore, this invention provides a pressure sensor and its manufacturing method that, by increasing the deformation, reduces the requirement for a specific GF value in the material while maintaining similar sensitivity; and by expanding the pressure sensor's operating pressure range, it achieves detection over a wider pressure range while maintaining high sensitivity over a narrower pressure range.

[0034] Please see Figure 1The diagram illustrates a cross-sectional view of a pressure sensor 100 according to some embodiments of the present invention. The pressure sensor 100 includes a support substrate 110 and a resistive substrate 130. The support substrate 110 includes a first substrate 115 and a patterned support layer 120A. The material of the first substrate 115 may have properties such as light transmittance, tensile strength, compressibility, and insulation. In some embodiments, the material of the first substrate 115 is polydimethylsiloxane (PDMS) or other materials having at least one of the aforementioned properties.

[0035] A patterned support layer 120A is disposed on the first substrate 115. The patterned support layer 120A is used to improve the bending resistance in local areas of the pressure sensor and provide support for the deformation of the resistor (described below). In some embodiments, the support substrate 110 may optionally include a first protective layer 125 to cover the first substrate 115 and the patterned support layer 120A. The first protective layer 125 is mainly provided to protect the patterned support layer 120A, and the first protective layer 125 may have properties such as insulation, light transmittance, and stretchability. In some embodiments, the first protective layer 125 may be a polymer such as optical adhesive, polyethylene (PE) film, or resin.

[0036] The resistor substrate 130 includes a second substrate 140. The second substrate 140 has a corrugated surface 142 and a back surface 144 opposite to the corrugated surface 142, wherein the corrugated surface 142 faces the support substrate 110. In other words, the second substrate 140 is a corrugated substrate, and the corrugated surface 142 is closer to the support substrate 110. The corrugated surface 142 includes staggered crest regions 140A and trough regions 140B. Although Figure 1 Only one crest region 140A and two trough regions 140B are shown in the diagram, but the invention is not limited thereto. The distance between the trough region 140B and the back surface 144 is greater than the distance between the crest region 140A and the back surface 144. In other words, the thickness of the second substrate 140 in the trough region 140B is greater than the thickness in the crest region 140A.

[0037] In some embodiments, the resistor substrate 130 may selectively include a third substrate 135 on the second substrate 140. Similar to the material of the first substrate 115, the materials of the second substrate 140 and the third substrate 135 may also have properties such as light transmittance, tensile strength, compressibility, and insulation. In some embodiments, the second substrate 140 and the third substrate 135 are the same material, such as polydimethylsiloxane. In other embodiments, the second substrate 140 and the third substrate 135 are different materials.

[0038] The resistor substrate 130 also includes a plurality of conductive portions 150 and a plurality of resistive portions (e.g., a first resistor R1 and a second resistor R2). The conductive portions 150, the first resistor R1, and the second resistor R2 are all disposed on the corrugated surface 142 of the second substrate 140. In some embodiments, the conductive portions 150 and the resistive portions are staggered, such as... Figure 1 As shown, the two ends of the first resistor R1 are respectively connected to the wire portion 150, and the two ends of the second resistor R2 are also respectively connected to the wire portion 150. In some embodiments, the first resistor R1 is disposed in the trough region 140B of the second substrate 140, while the second resistor R2 is disposed in the peak region 140A of the second substrate 140. The main function of the wire portion 150 is to transmit signals. In some embodiments, the wire portion 150 may be copper. In other embodiments, the wire portion 150 may also be a conductive nanomaterial such as a translucent silver nanowire.

[0039] In some embodiments, the first resistor R1 and the second resistor R2 are thin-film resistors. The first resistor R1 and the second resistor R2 may be transparent and stretchable, and their resistance values ​​change with bending, stretching, or compression. In some embodiments, the materials of the first resistor R1 and the second resistor R2 include transparent conductive materials such as nano-silver, nano-copper, and carbon nanotubes. The sheet resistance, transmittance, and thickness of the first resistor R1 and the second resistor R2 must be adjusted according to the sensitivity requirements of the pressure sensor 100. To design the required resistance values, in some embodiments, the first resistor R1 and the second resistor R2 may be formed into serpentine or linear patterns by methods such as etching.

[0040] In some embodiments, the resistor substrate 130 may selectively include a second protective layer 160 disposed on the corrugated surface 142 of the second substrate 140 to cover the plurality of conductive portions 150 and the plurality of resistive portions. In other words, the second protective layer 160 is further away from the corrugated surface 142 of the second substrate 140 than the conductive portions 150 and the resistive portions. The second protective layer 160 is primarily provided to protect the conductive portions 150, the first resistor R1, and the second resistor R2, and the second protective layer 160 may have properties such as insulation, light transmittance, and stretchability. In some embodiments, the second protective layer 160 may be a polymer such as optical adhesive, polyethylene film, or resin.

[0041] A resistive substrate 130 is disposed on a support substrate 110. In some embodiments, an air gap 170 is included between the resistive substrate 130 and the support substrate 110 so that the pressure sensor 100 can generate a large deformation under a small external force, and thus the resistance changes with the deformation. In some embodiments, the first resistor R1 in the trough region 140B of the resistive substrate 130 corresponds to the patterned support layer 120A of the support substrate 110, that is, the patterned support layer 120A is directly below the first resistor R1.

[0042] When the pressure sensor 100 is subjected to low pressure, the first protective layer 125 and the second protective layer 160 are not in contact, resulting in a larger deformation of the second resistor R2 and a more significant change in its resistance value. Conversely, because the first resistor R1 has high bending strength, its deformation is smaller, and therefore its resistance value changes less. Conversely, when the pressure is high, causing the first protective layer 125 to contact the second protective layer 160, the first resistor R1 will be compressed by the patterned support layer 120A, resulting in deformation (e.g., bending and compression), and thus a more significant change in its resistance value. In other words, the deformation of the first resistor R1 is more easily controlled under the influence of the patterned support layer 120A. Furthermore, the pressure sensor 100 is tensile, making it suitable for wearable health monitoring sensors.

[0043] Please see Figures 2A to 2D This illustrates a cross-sectional view of the support substrate 110 at an intermediate stage of its manufacturing process according to some embodiments of the present invention. Figure 2A As shown, a substrate 101 is provided, which includes a first substrate 115 and a support layer 120 on the first substrate 115. In some embodiments, the substrate 101 may be a flexible copper clad laminate (FCCL), in which case the first substrate 115 is an insulating substrate, and the support layer 120 is copper foil. Next, as... Figure 2B As shown, a photoresist layer 105 is formed on the support layer 120.

[0044] right Figure 2B After the structure is exposed, developed, etched, and the remaining photoresist layer is removed in sequence, the support layer 120 can be patterned to obtain, as shown in the figure. Figure 2C The structure shown includes a patterned support layer 120A on a first substrate 115. Then, it is possible to... Figure 2C A first protective layer 125 is formed on the structure to cover the patterned support layer 120A and the exposed upper surface of the first substrate 115, such as Figure 2D As shown. The first protective layer 125 is used to protect the patterned support layer 120A and may have properties such as insulation, light transmittance, and stretchability. In some embodiments, the first protective layer 125 may be a polymer such as optical adhesive, polyethylene film, or resin.

[0045] Please see Figures 3A to 3E This illustrates a cross-sectional view of a resistor substrate 130 at an intermediate stage of its manufacturing process according to some embodiments of the present invention. Firstly, as... Figure 3A As shown, a substrate stack 131 is provided, which includes a second substrate 140 and a third substrate 135 on the second substrate 140. In some embodiments, the second substrate 140 and the third substrate 135 are composed of the same material and are integrally formed substrates. In other embodiments, the second substrate 140 and the third substrate 135 are composed of different materials.

[0046] Next, an imprinting or transfer process is performed on the substrate stack 131 to form a wavy substrate on the second substrate 140, such as... Figure 3B As shown. The second substrate 140 has a corrugated surface 142 and a back surface 144 on the opposite side of the corrugated surface 142 and attached to the third substrate 135. The second substrate 140 includes staggered crest regions 140A and trough regions 140B, wherein the distance between the trough region 140B and the back surface 144 is greater than the distance between the crest region 140A and the back surface 144.

[0047] Please see Figure 3C A conductive layer 152 is formed on the corrugated surface 142 of the second substrate 140. In some embodiments, the conductive layer 152 can be formed by methods such as spin coating, chemical plating, sputtering, chemical vapor deposition (CVD), or physical vapor deposition (PVD). In some embodiments, the conductive layer 152 is composed of copper, silver nanowires, or other conductive materials, preferably a light-transmitting material.

[0048] Next, the conductive layer 152 (reference) Figure 3C A patterning process is performed to form multiple conductive portions 150. The patterning process includes forming a photoresist layer on the conductive layer 152, followed by exposure, development, and etching. Then, multiple resistive portions (including a first resistor R1 and a second resistor R2) are bonded to the conductive portions 150, and the remaining photoresist layer is removed to obtain a patterned surface. Figure 3DThe structure is shown. In some embodiments, the first resistor R1 and the second resistor R2 may be composed of transparent conductive materials such as nano-silver, nano-copper, and carbon nanotubes. As shown in FIG3D, the first resistor R1 is formed in the trough region 140B of the second substrate 140, and the second resistor R2 is formed in the crest region 140A of the second substrate 140. In other words, the conductor portion 150 is disposed on the corrugated surface 142 outside the crest region 140A and the trough region 140B.

[0049] like Figure 3E As shown, a second protective layer 160 is formed to cover the conductor portion 150, the first resistor R1, and the second resistor R2, thereby obtaining the resistor substrate 130. In some embodiments, the second protective layer 160 has insulation, light transmittance, and stretchability, and can be a polymer such as optical adhesive, polyethylene film, or resin. Then, ... Figure 3E The resistor substrate 130 and Figure 2D By aligning and bonding the support substrate 110, the desired result can be obtained. Figure 1 Pressure sensor 100. In some embodiments, the alignment and bonding involves aligning the two first resistors R1 of the resistive substrate 130 with the two patterned support layers 120A of the support substrate 110, respectively.

[0050] Please see Figure 4 This diagram illustrates a planar projection of a pressure sensor 200 according to some embodiments of the present invention. The resistive substrate 230 includes a plurality of first resistors R1 and a plurality of second resistors R2 arranged in an alternating manner. Although Figure 4 The resistor substrate 230 shown on the left is a 6×6 resistor structure. In other embodiments, it may be other resistor arrangement structures. Figure 4 The support substrate 210 (located in) Figure 4 (On the right) Only the patterned support layer 220A is shown, which corresponds to each of the first resistors R1 in the resistor substrate 230. Each first resistor R1 and second resistor R2 has an independent signal path and is connected to the signal processor 202 respectively. The signal processor 202 is designed in the non-sensor area of ​​the flexible circuit board, and the functions of the signal processor 202 may include signal amplification, filtering, and logic control.

[0051] Please see Figure 5 The graph illustrates the relationship between the resistance value of a pressure sensor and pressure changes according to some embodiments of the present invention. Figure 5 It can be seen that the pressure sensor in some embodiments of the present invention is subjected to a small pressure (e.g., Figure 5 As shown in section OA), the pressure sensor exhibits a large rate of change in resistance, indicating high sensitivity. However, under significant pressure (e.g., when subjected to high pressure), the sensor's resistance changes rapidly. Figure 5As shown in section ab), the rate of change of resistance is relatively reduced. The advantage of the pressure sensor of the present invention is that it expands the operating pressure range of the pressure sensor, enabling detection under high pressure and maintaining high sensitivity under low pressure.

[0052] As described above, the present invention provides a pressure sensor and a method for manufacturing the same, which reduces the requirement for the sensitivity coefficient of the resistive material by increasing the deformation of the resistor. Furthermore, by allowing the resistive portion to exhibit corresponding deformation under different pressures, and by causing a significant change in resistance value, the sensitivity of the pressure sensor is improved, and it has a wider operating pressure range.

[0053] Although the present invention has been disclosed above with reference to several embodiments, it is not intended to limit the present invention. Those skilled in the art can make various modifications and refinements without departing from the spirit and scope of the present invention. Therefore, the scope of protection of the present invention shall be determined by the scope of the appended claims.

[0054] [Symbol Explanation]

[0055] 100: Pressure sensor

[0056] 101:Substrate

[0057] 105: Photoresist layer

[0058] 110: Supporting substrate

[0059] 115: First substrate

[0060] 120: Support layer

[0061] 120A: Patterned support layer

[0062] 125: First protective layer

[0063] 130: Resistor substrate

[0064] 131: Substrate stacking

[0065] 135: Third substrate

[0066] 140: Second substrate

[0067] 140A: Peak area

[0068] 140B: Valley Area

[0069] 142: Wavy surface

[0070] 144: Back

[0071] 150: Conductor section

[0072] 152: Conductive layer

[0073] 160: Second protective layer

[0074] 170: Air gap

[0075] 200: Pressure sensor

[0076] 202: Signal Processor

[0077] 210: Support substrate

[0078] 220A: Patterned support layer

[0079] 230: Resistor substrate

[0080] R1: First resistor

[0081] R2: Second resistor

[0082] oa,ab: Section.

Claims

1. A pressure sensor, characterized in that, Include: Support substrate, comprising: Substrate; and A patterned support layer is disposed on the substrate; A resistor substrate is disposed on the support substrate, wherein the resistor substrate comprises: A wavy substrate has a wavy surface and a back surface opposite to the wavy surface, wherein the wavy surface includes a plurality of crest regions and a plurality of trough regions, the crest regions and the trough regions are arranged alternately, the distance between the back surface and the crest regions is smaller than the distance between the back surface and the trough regions, and the wavy surface faces the patterned support layer. Multiple conductive sections are disposed on the corrugated surface of the corrugated substrate; and Multiple resistor portions are disposed on the wavy surface of the wavy substrate, wherein the multiple wire portions and the multiple resistor portions are alternately arranged, the multiple resistor portions include multiple first resistors and multiple second resistors, the multiple first resistors are disposed in the trough area of ​​the wavy substrate, and the multiple second resistors are disposed in the crest area of ​​the wavy substrate, the patterned support layer is located below the multiple first resistors, and the patterned support layer is not located below the multiple second resistors; as well as An air gap is provided between the resistor substrate and the support substrate.

2. The pressure sensor according to claim 1, characterized in that, Also includes: An insulating substrate is disposed on the back side of the corrugated substrate.

3. The pressure sensor according to claim 1, characterized in that, Also includes: A first protective layer covers the substrate and the patterned support layer; and The second protective layer covers the plurality of wire portions and the plurality of resistor portions.

4. The pressure sensor according to claim 1, characterized in that, Each of the plurality of resistor sections has a serpentine pattern or a linear pattern.

5. The pressure sensor according to claim 1, characterized in that, The materials of the multiple resistive components include nano-silver, nano-copper, and carbon nanotubes.

6. A method for manufacturing a pressure sensor, characterized in that, Include: A support substrate is provided, wherein the support substrate includes a first substrate and a support layer, and the support layer is on the first substrate; A photoresist layer is formed on the support layer; The support layer is patterned using the photoresist layer; A second substrate is patterned to give the second substrate a wavy surface and a back surface relative to the wavy surface, wherein the second substrate includes a plurality of crest segments and a plurality of trough segments, the crest segments and the trough segments being arranged alternately. A conductive layer is formed on the wavy surface of the second substrate; The conductive layer is patterned to form multiple conductive wire portions; A plurality of resistive portions are joined with the conductive portion to obtain a resistive substrate, wherein the plurality of resistive portions include a plurality of first resistors and a plurality of second resistors, the plurality of first resistors being disposed in the trough section and the plurality of second resistors being disposed in the crest section; as well as The support substrate and the resistor substrate are bonded together, wherein the distance between the support substrate and the peak section is greater than the distance between the support substrate and the trough section, and an air gap is included between the support substrate and the resistor substrate.

7. The method for manufacturing a pressure sensor according to claim 6, characterized in that, Also includes: A cover film is formed on the surface of the support substrate to cover the first substrate and the support layer.

8. The method of manufacturing a pressure sensor according to claim 6, wherein before patterning the second substrate, it is characterized in that, Also includes: A substrate stack is provided, wherein the substrate stack includes a second substrate and a third substrate, and the third substrate is disposed on the back side of the second substrate.

9. The method for manufacturing a pressure sensor according to claim 6, characterized in that, Also includes: A protective film is formed on the plurality of resistive portions and the conductive portions.

10. The method for manufacturing a pressure sensor according to claim 6, characterized in that, Patterning the conductive layer includes: Remove portions of the conductive layer in the crest and trough regions of the second substrate.

Images