Composite flexible substrate and its fabrication method

Abstract

The present invention provides a composite flexible substrate and a manufacturing method thereof, comprising: comprising a plurality of metal matrix modules and a plurality of polymer matrix modules, wherein: the metal matrix modules and the polymer matrix modules are staggered in a regular pattern so that any two polymer matrix modules are separated by the metal matrix modules; the contact surfaces of the metal matrix modules and the polymer matrix modules are fixedly connected; the staggered metal matrix modules and the polymer matrix modules together constitute a rectangular metal-polymer composite flexible substrate.

Description

Technical Field

[0001] The present invention relates to the technical field of micro-electromechanical systems, and in particular to a composite flexible substrate and a manufacturing method thereof. Background Art

[0002] As one of the necessary components of flexible micro-electromechanical systems (MEMS) devices, flexible substrates are widely used in flexible MEMS devices such as flexible strain sensors and temperature sensors. Compared with the fixed structure, brittle materials, and non-deformable characteristics of traditional MEMS devices, flexible MEMS devices have the characteristics of being bendable, easy to stretch, and having strong deformation adaptability, and are therefore used in sensing tests in environments with more complex working conditions and morphologies. However, the semiconductor materials and metal materials used in traditional MEMS devices are mostly brittle, with low ductility and poor deformation ability, while polymer materials mostly show better ductility, bending and deformation capabilities. Therefore, existing flexible substrates are mostly made of polymer materials.

[0003] However, flexible substrates made of polymer materials will undergo thermal expansion when used in a high temperature environment. The deformation caused by the thermal expansion of the substrate itself will further cause the sensitive materials installed on the substrate to deform, thereby causing non-negligible error effects on the sensor test data of the MEMS device. Summary of the invention

[0004] The object of the present invention is to provide a composite flexible substrate and a manufacturing method thereof, so as to solve the problem that thermal expansion of the existing flexible substrate made of polymer material brings errors to the sensor test data of MEMS device.

[0005] In order to solve the above technical problems, the present invention provides a composite flexible substrate, comprising a plurality of metal matrix modules and a plurality of polymer matrix modules, wherein:

[0006] The metal matrix modules and the polymer matrix modules are arranged in a staggered manner so that any two polymer matrix modules are separated by the metal matrix modules;

[0007] The metal matrix module is fixedly connected to the contact surface of the polymer matrix module;

[0008] The staggered metal matrix modules and the polymer matrix modules together form a rectangular metal-polymer composite flexible substrate.

[0009] Optionally, in the composite flexible substrate, the metal matrix module and the polymer matrix module are both rectangular parallelepipeds, and the planes formed by the plurality of metal matrix modules and the polymer matrix modules along their length direction and height direction are in close contact;

[0010] The length direction of each metal matrix module is parallel to the width direction of the metal-polymer composite flexible substrate, and the length direction of the polymer matrix module is also parallel to the width direction of the metal-polymer composite flexible substrate.

[0011] Optionally, in the composite flexible substrate, the length direction of the metal-polymer composite flexible substrate is the arrangement direction, the length direction of the metal matrix module forms a certain angle with the arrangement direction, and the angle is between 30° and 135°;

[0012] The angle is adjusted to adjust the ratio of the thermal expansion coefficients of the polymer matrix modules along the arrangement direction and perpendicular to the arrangement direction.

[0013] Optionally, in the composite flexible substrate, one or more of the aspect ratio of the metal matrix module, the distribution number of the metal matrix modules, the length of the metal matrix module, and the width of the metal matrix module are adjusted to adjust the anisotropy of the thermal expansion coefficient of the polymer matrix module along the arrangement direction and perpendicular to the arrangement direction.

[0014] Optionally, in the composite flexible substrate, the shapes of the metal matrix module and the polymer matrix module include two triangular prisms with right-angled triangle cross-sections, a plurality of quadrangular prisms with isosceles trapezoid cross-sections, and a plurality of identical parallelepipeds, wherein the heights of all triangular prisms, quadrangular prisms, and parallelepipeds are equal;

[0015] The triangular prisms, quadrangular prisms and parallelepipeds are closely arranged with the plane perpendicular to the height direction as the contact surface to form a rectangular metal-polymer composite flexible substrate.

[0016] Optionally, in the composite flexible substrate, the material of the polymer matrix module is polydimethylsiloxane or polyimide or polyethylene.

[0017] Optionally, in the composite flexible substrate, the material of the metal base module is nickel or copper.

[0018] Optionally, in the composite flexible substrate, the metal base module is formed by electroplating metal.

[0019] The present invention also provides a method for manufacturing the composite flexible substrate as described above, comprising:

[0020] Preparing a plurality of metal matrix modules and polymer matrix modules in the shape of rectangular parallelepipeds, and arranging the metal matrix modules and the polymer matrix modules along an arrangement direction to directly form a rectangular parallelepiped metal-polymer composite flexible substrate;

[0021] The length direction of the metal matrix module is parallel to the width direction of the metal-polymer composite flexible substrate, so as to reduce the thermal expansion deformation of the metal matrix module in the length direction.

[0022] The present invention also provides a method for manufacturing the composite flexible substrate as described above, comprising:

[0023] Preparing a plurality of metal matrix modules and polymer matrix modules in the shape of rectangular parallelepiped, and arranging the metal matrix modules and the polymer matrix modules along an arrangement direction to form a substrate material layer;

[0024] Determine the angle between the side surface of the rectangular metal-polymer composite flexible substrate and the arrangement direction according to the purpose of the composite flexible substrate, and cut the substrate material layer according to the angle to form a rectangular metal-polymer composite flexible substrate;

[0025] The composite flexible substrate can adjust the thermal expansion coefficient of the composite flexible substrate, and is suitable for the production of flexible substrates with flexible applications for multiple purposes;

[0026] The ratio of the thermal expansion coefficients of the polymer matrix modules along the arrangement direction and perpendicular to the arrangement direction is adjusted by adjusting the angle.

[0027] In the composite flexible substrate and the manufacturing method thereof provided by the present invention, the metal matrix module and the polymer matrix module are arranged in a staggered manner according to a rule so that any two polymer matrix modules are separated by the metal matrix module, and the contact surfaces of the metal matrix module and the polymer matrix module are fixedly connected, so that when the composite flexible substrate is applied to a high temperature environment, since the thermal expansion coefficient of the metal matrix module is smaller than that of the polymer matrix module, in the direction perpendicular to the arrangement, the two materials will generate thermal stress at the contact surface due to the mismatch of the thermal expansion coefficients, and the elastic modulus of the metal is much larger than the elastic modulus of the polymer. Therefore, the stress will generate a constraint force on the deformation of the polymer along the tangential direction of the contact surface, greatly limiting the thermal expansion deformation of the polymer matrix along this direction, while the deformation of the metal matrix part due to the stress is very small. For the detection quantity disturbed by the error in the direction perpendicular to the arrangement, the structure can effectively eliminate the error caused by the thermal expansion of the composite flexible substrate to the sensor test data of the MEMS device.

[0028] In addition, the polymer matrix module can expand freely along the arrangement direction, but is restricted by the metal matrix module in the direction perpendicular to the arrangement direction. The polymer matrix module exhibits anisotropy of thermal expansion coefficient in two directions, which makes the overall thermal expansion coefficient of the composite flexible substrate anisotropic. The thermal expansion coefficient of the composite flexible substrate in different directions can be precisely controlled by adjusting the depth-to-width ratio, distribution number, arrangement direction, length and width of the metal matrix module. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 is a schematic diagram of a composite flexible substrate according to an embodiment of the present invention;

[0030] Figure 2 It is a schematic diagram of a composite flexible substrate in which a metal base module and a polymer base module are both rectangular parallelepipeds in one embodiment of the present invention;

[0031] Figure 3 It is a schematic diagram of a composite flexible substrate metal base module according to an embodiment of the present invention, in which the length direction and the arrangement direction are not perpendicular;

[0032] Figure 4 It is a schematic diagram of a method for manufacturing a composite flexible substrate according to an embodiment of the present invention. DETAILED DESCRIPTION

[0033] The following is a further detailed description of the composite flexible substrate and the method for manufacturing the same proposed by the present invention in conjunction with the accompanying drawings and specific embodiments. The advantages and features of the present invention will become more apparent from the following description and claims. It should be noted that the accompanying drawings are in a very simplified form and are not in precise proportions, and are only used to conveniently and clearly assist in explaining the purpose of the embodiments of the present invention.

[0034] In addition, unless otherwise specified, the features in different embodiments of the present invention may be combined with each other. For example, a feature in the second embodiment may be used to replace a corresponding feature in the first embodiment or a feature with the same or similar function, and the resulting embodiment also falls within the disclosure or description scope of the present application.

[0035] The core idea of ​​the present invention is to provide a composite flexible substrate and a manufacturing method thereof, so as to solve the problem that thermal expansion of the existing flexible substrate made of polymer material brings errors to the sensor test data of MEMS device.

[0036] To realize the above idea, the present invention provides a composite flexible substrate and a method for manufacturing the same, comprising: a plurality of metal matrix modules and a plurality of polymer matrix modules, wherein: the metal matrix modules and the polymer matrix modules are staggered in a regular pattern so that any two polymer matrix modules are separated by the metal matrix modules; the contact surfaces of the metal matrix modules and the polymer matrix modules are fixedly connected; the staggered metal matrix modules and the polymer matrix modules together constitute a rectangular metal-polymer composite flexible substrate.

[0037] In addition, in addition to eliminating the error caused by the thermal expansion of the flexible substrate to the sensor test data of the MEMS device, the purpose of the present invention is to propose different embodiments based on the following insights: In actual engineering applications, the change of physical quantities in a certain direction will become the main object of attention, while the physical quantities in another direction show a small or even negligible effect. Selectively enhancing the perception of physical quantities in the direction of attention is also more in line with the needs of actual engineering. When focusing on the impact of temperature on the flexible substrate, the thermal expansion of the flexible substrate made of polymer material is isotropic, and the deformation capacity of the flexible substrate in different directions cannot be artificially adjusted.

[0038] Among the existing flexible substrates, composite flexible substrates made of metal and polymer are mostly made by doping metal particles or nanowires into polymers, such as Zhang Shangjie et al. from the University of Electronic Science and Technology of China in 2015, who mixed nanosilver particles with polydimethylsiloxane (PDMS) to make a flexible substrate with the ability to sense strain in "Highly stretchable, sensitive, and flexible strain sensors based on silver nanoparticles / carbon nanotubes composites". Or by sputtering a metal film on the polymer surface, such as Faurie D et al. from the University of Paris 13 in 2019, who sputtered a nickel metal film on the polyimide surface to make a composite flexible substrate in "In situ x-ray diffraction analysis of 2D crack patterning in thin films". The existing manufacturing process method of compounding metal and polymer cannot produce a composite flexible substrate that can selectively adjust the thermal expansion coefficient in different directions, and cannot effectively eliminate the error caused by the thermal expansion of the flexible substrate to the sensor test data of the MEMS device. Meanwhile, the above manufacturing method mixes the sensitive layer material with the flexible substrate, or combines them in layers, and does not really prepare a metal-polymer composite flexible substrate that is only used as a substrate structure.

[0039] Based on the above insights, the present invention proposes a metal-polymer composite flexible substrate with anisotropy of thermal expansion, adjustable thermal expansion coefficient, and low internal stress, and hopes that its process is as simple and convenient as possible, so that people can more conveniently manufacture such a composite flexible substrate for large-scale application in complex working conditions. The present invention relates to a device in the field of micro-electromechanical system technology, specifically a metal-polymer composite flexible substrate with adjustable anisotropy of thermal expansion.

[0040] This embodiment provides a metal-polymer composite flexible substrate with adjustable anisotropy of thermal expansion coefficient, such as Figure 1 As shown, it includes a plurality of metal matrix modules 1 and a plurality of polymer matrix modules 2, wherein: the metal matrix modules 1 and the polymer matrix modules 2 are arranged in an interlaced manner according to a rule, so that any two polymer matrix modules 2 are separated by the metal matrix modules 1; for example, an arrangement of "polymer matrix module 2 - metal matrix module 1 - polymer matrix module 2" is formed. The contact surfaces of the metal matrix modules 1 and the polymer matrix modules 2 are fixedly connected; the interlaced metal matrix modules 1 and the polymer matrix modules 2 together constitute a metal-polymer composite flexible substrate. The metal matrix modules 1 in the composite flexible substrate can form a certain angle with the arrangement direction, and the angle is adjustable.

[0041] In one embodiment of the present invention, Figure 2 As shown, the arrangement of the metal matrix module 1 and the polymer matrix module 2 ultimately forms a rectangular composite flexible substrate, wherein the metal matrix module 1 and the polymer matrix module 2 are both small rectangular blocks, and the planes formed by the plurality of small rectangular blocks along the length direction and the height direction are in close contact and fixedly connected. That is, the length direction of each metal matrix module 1 can be parallel to the width direction of the rectangular composite flexible substrate, and the length direction of the polymer matrix module 2 is also parallel to the width direction of the rectangular composite flexible substrate.

[0042] In this embodiment, when the ambient temperature rises, the composite flexible substrate begins to deform due to thermal expansion. Generally, the thermal expansion coefficient of metal is smaller than that of polymer. At the same temperature, the thermal expansion deformation amount generated by metal is smaller than that generated by polymer. In the arrangement direction (the length direction of the rectangular composite flexible substrate), the polymer matrix module 2 can expand freely to both ends; but in the direction perpendicular to the arrangement direction, the metal matrix and the polymer matrix are fixedly connected, and the two materials will generate thermal stress at the contact surface due to the mismatch of thermal expansion coefficients. The elastic modulus of the metal is much larger than the elastic modulus of the polymer. Therefore, the stress will constrain the deformation of the polymer along the tangential direction of the contact surface, greatly limiting the thermal expansion deformation of the polymer matrix along this direction, while the deformation of the metal matrix part due to the stress is very small.

[0043] In another embodiment of the present invention, Figure 3 As shown, the arrangement of the metal matrix module 1 and the polymer matrix module 2 ultimately forms a rectangular composite flexible substrate, and the shapes of the metal matrix module 1 and the polymer matrix module 2 include two identical triangular prisms, multiple quadrangular prisms, and multiple identical parallelepipeds, wherein the heights of all triangular prisms, quadrangular prisms, and parallelepipeds are equal.

[0044] Among them, the cross section of each tetrahedron is an isosceles trapezoid. Half of the tetrahedrons are stacked to form a large isosceles trapezoid, and the other half of the tetrahedrons are stacked to form the same large isosceles trapezoid. The cross section of the triangular prism is a right triangle. The long side of the right triangle is equal to the upper base of the large isosceles trapezoid. A triangular prism is stacked on a large isosceles trapezoid to form a large triangular prism. The cross section of the large triangular prism is a large right triangle. The long side of the large right triangle is equal to the length of the parallelepiped. The planes formed by the parallelepiped along the length direction and the height direction are in close contact to form a large parallelepiped. The two large right triangles are distributed on both sides of the large parallelepiped. That is, the length direction of the composite flexible substrate is the arrangement direction.

[0045] In this embodiment, the polymer matrix module 2 exhibits anisotropy of thermal expansion coefficient in the two directions along the arrangement direction and perpendicular to the arrangement direction, which in turn causes the entire composite flexible substrate to exhibit anisotropy of thermal expansion coefficient in these two directions. In addition, the metal matrix module 1 is at a certain angle to the arrangement direction, and regulating the angle can further fine-tune the ratio of thermal expansion coefficients along the arrangement direction and perpendicular to the arrangement direction. By regulating the depth-to-width ratio, distribution number, arrangement direction, length and width of the metal matrix module 1, etc., the anisotropy of the thermal expansion coefficient of the polymer matrix module 2 can be regulated, thereby achieving precise regulation of the thermal expansion coefficient of the composite flexible substrate in different directions.

[0046] In one embodiment of the present invention, a method for manufacturing a composite flexible substrate includes: Figure 4 As shown, a plurality of metal matrix modules 1 and polymer matrix modules 2 in the shape of small cuboids are prepared. After the metal matrix modules 1 and the polymer matrix modules 2 are arranged along the arrangement direction, a composite flexible substrate is directly formed in which the length direction of the metal matrix module 1 is parallel to the width direction of the composite flexible substrate. The advantage of the composite flexible substrate is that it is suitable as a metal-polymer composite flexible substrate with low internal stress.

[0047] In another embodiment of the present invention, the method for manufacturing a composite flexible substrate may further include: preparing a plurality of metal matrix modules 1 and polymer matrix modules 2 in the shape of small rectangular blocks, arranging the metal matrix modules 1 and the polymer matrix modules 2 along an arrangement direction to form a substrate material layer having an area larger than that of the composite flexible substrate, determining the angle between the side surface of the rectangular composite flexible substrate and the arrangement direction according to the purpose of the composite flexible substrate (such as temperature sensor, strain sensor, etc., different purposes have different thermal expansion anisotropy requirements), and cutting the substrate material layer according to the angle to form a rectangular composite flexible substrate; the composite flexible substrate can regulate the thermal expansion coefficient of the composite flexible substrate, and is suitable for the manufacture of a composite flexible substrate with flexible applications for multiple purposes.

[0048] The metal matrix module 1 in the composite flexible substrate is formed by electroplating metal. The polymer matrix module 2 in the composite flexible substrate is polydimethylsiloxane or polyimide or polyethylene. The metal matrix module 1 in the composite flexible substrate is nickel or copper. The length of the metal matrix module 1 is 5000 to 12000 microns, the width is 50 to 5000 microns, and the height is 5 to 50 microns; the length of the polymer matrix module 2 is 5000 to 12000 microns, the width is 50 to 5000 microns, and the height is 5 to 50 microns; the width of the two matrix modules may be inconsistent, but the height needs to be consistent. When the metal matrix module 1 is perpendicular to the arrangement direction, the lengths of the two matrixes need to be consistent. When the metal matrix module 1 is at a certain angle to the arrangement direction, the composite flexible substrate composed of the two matrix modules needs to keep the edges straight.

[0049] The present invention provides a metal-polymer composite flexible substrate with adjustable anisotropic thermal expansion coefficient. It is mainly composed of a metal matrix module 1 and a polymer matrix module 2. The metal matrix module 1 and the polymer matrix module 2 are arranged in an orderly staggered and spaced manner to form a composite flexible substrate together. When the composite flexible substrate of the present invention is applied to a high temperature environment, since the thermal expansion coefficient of the metal matrix module 1 is smaller than that of the polymer matrix module 2, the polymer matrix module 2 can expand freely along the arrangement direction, but is restricted by the metal matrix module 1 in a direction perpendicular to the arrangement direction. The polymer matrix module 2 exhibits anisotropy of thermal expansion coefficient in two directions, thereby making the overall thermal expansion coefficient of the composite flexible substrate anisotropic. The precise regulation of the thermal expansion coefficient of the composite flexible substrate in different directions is achieved by adjusting the depth-to-width ratio of the metal matrix module 1, the number of metal matrix modules distributed, the arrangement direction of the metal matrix module, the length of the metal matrix module, and the width of the metal matrix module.

[0050] In summary, the above embodiments describe in detail different configurations of the composite flexible substrate. Of course, the present invention includes but is not limited to the configurations listed in the above embodiments. Any content that is changed based on the configurations provided in the above embodiments belongs to the scope of protection of the present invention. Those skilled in the art can draw inferences based on the contents of the above embodiments.

[0051] In this specification, each embodiment is described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same or similar parts between the embodiments can be referred to each other. For the system disclosed in the embodiment, since it corresponds to the method disclosed in the embodiment, the description is relatively simple, and the relevant parts can be referred to the method part.

[0052] The above description is only a description of the preferred embodiments of the present invention, and is not intended to limit the scope of the present invention. Any changes or modifications made by a person skilled in the art in the field of the present invention based on the above disclosure shall fall within the scope of protection of the claims.

Claims

1. A composite flexible substrate, characterized in that: It includes a plurality of metal matrix modules and a plurality of polymer matrix modules, wherein: The metal matrix modules and the polymer matrix modules are arranged in a staggered manner so that any two polymer matrix modules are separated by the metal matrix modules; The metal matrix module is fixedly connected to the contact surface of the polymer matrix module; The staggered metal matrix modules and polymer matrix modules together form a rectangular metal-polymer composite flexible substrate. The length direction of the metal-polymer composite flexible substrate is the arrangement direction, and the length direction of the metal matrix module forms a certain angle with the arrangement direction, and the angle is between 30° and 135°; The angle is adjusted to adjust the ratio of the thermal expansion coefficients of the polymer matrix modules along the arrangement direction and perpendicular to the arrangement direction. wherein one or more of the aspect ratio of the metal matrix module, the number of distribution of the metal matrix modules, the length of the metal matrix module, and the width of the metal matrix module are adjusted to adjust the anisotropy of the thermal expansion coefficient of the polymer matrix module along the arrangement direction and perpendicular to the arrangement direction, The different metal matrix modules do not contact each other.

2. The composite flexible substrate according to claim 1, characterized in that: The shapes of the metal matrix module and the polymer matrix module include two triangular prisms with right triangle cross sections, a plurality of quadrangular prisms with isosceles trapezoid cross sections, and a plurality of identical parallelepipeds, wherein the heights of all triangular prisms, quadrangular prisms, and parallelepipeds are equal; The triangular prisms, quadrangular prisms and parallelepipeds are closely arranged with the plane perpendicular to the height direction as the contact surface to form a rectangular metal-polymer composite flexible substrate.

3. The composite flexible substrate according to claim 1, characterized in that: The material of the polymer matrix module is polydimethylsiloxane, polyimide or polyethylene.

4. The composite flexible substrate according to claim 1, characterized in that: The material of the metal base module is nickel or copper.

5. The composite flexible substrate according to claim 1, characterized in that: The metal base module is formed by electroplating metal.

6. A method for manufacturing the composite flexible substrate as claimed in claim 1, characterized in that: include: Preparing a plurality of metal matrix modules and polymer matrix modules in the shape of rectangular parallelepiped, and arranging the metal matrix modules and the polymer matrix modules along an arrangement direction to form a substrate material layer; Determine the angle between the side surface of the rectangular metal-polymer composite flexible substrate and the arrangement direction according to the purpose of the composite flexible substrate, and cut the substrate material layer according to the angle to form a rectangular metal-polymer composite flexible substrate; The composite flexible substrate can adjust the thermal expansion coefficient of the flexible substrate, and is suitable for the production of a composite flexible substrate that can be flexibly applied for multiple purposes; The ratio of the thermal expansion coefficients of the polymer matrix modules along the arrangement direction and perpendicular to the arrangement direction is adjusted by adjusting the angle.

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