阅读说明：本技术 一种金属复合柔性衬底及其制备方法 (Metal composite flexible substrate and preparation method thereof ) 是由 杨卓青 李梦秋 李亚辉 王艳 于 2021-08-26 设计创作，主要内容包括：本发明涉及柔性衬底技术领域,提出一种金属复合柔性衬底及其制备方法。该衬底包括：聚合物结构；以及金属微结构,其与所述聚合物结构交错间隔布置；其中,所述聚合物结构和所述金属微结构的厚度相同,并且通过所述聚合物结构和所述金属微结构的宽度、宽度比例以及布置方向确定所述金属复合柔性衬底的热膨胀系数各向异性。该衬底的制备方法中包含了对金属与聚合物之间的界面进行修饰与改性设计,可以实现金属微结构与聚合物结构之间良好、稳定、可靠的界面结合。通过该衬底表现出的热膨胀各向异性并且可调控性,使得柔性电阻式应变传感器可以摆脱因环境温度变化造成衬底的额外形变的影响,从而确保电阻式应变传感器在特定方向上探测的精准度。(The invention relates to the technical field of flexible substrates, and provides a metal composite flexible substrate and a preparation method thereof. The substrate includes: a polymer structure; and metal microstructures which are arranged in a staggered and spaced mode with the polymer structure; wherein the thicknesses of the polymer structure and the metal microstructure are the same, and the thermal expansion coefficient anisotropy of the metal composite flexible substrate is determined by the widths, the width ratios and the arrangement directions of the polymer structure and the metal microstructure. The preparation method of the substrate comprises the modification and modification design of the interface between the metal and the polymer, and can realize good, stable and reliable interface combination between the metal microstructure and the polymer structure. The thermal expansion anisotropy and the adjustability of the substrate are realized, so that the flexible resistance-type strain sensor can get rid of the influence of extra deformation of the substrate caused by the change of the environmental temperature, and the detection accuracy of the resistance-type strain sensor in a specific direction is ensured.)

1. A metal composite flexible substrate, comprising:

a polymer structure; and

metal microstructures in staggered spaced arrangement with the polymer structure;

the thicknesses of the polymer structure and the metal microstructure are the same, and the anisotropy and the controllability of the thermal expansion coefficient of the metal composite flexible substrate are determined by the widths of the polymer structure and the metal microstructure, the width ratio between the polymer structure and the metal microstructure and the arrangement direction of the polymer structure and the metal microstructure.

2. The metal composite flexible substrate of claim 1, wherein the metal microstructures comprise:

a microstructure groove;

the metal seed layer is positioned at the bottom of the microstructure groove; and

a filler metal filling the microstructure trenches.

3. The metal composite flexible substrate of claim 1, wherein the material of the polymer structure comprises polyimide.

4. The metal composite flexible substrate of claim 1, wherein the metal seed layer comprises a chromium metal layer and a copper metal layer; and/or

The material of the filler metal comprises copper.

5. The metal composite flexible substrate of claim 1, wherein the polymer structure and the metal microstructure have a thickness of 5-200 μ ι η.

6. The metal composite flexible substrate of claim 1, wherein the polymer structure has a width of 10-3000 μ ι η; and/or

The width of the metal microstructure is 10-300 μm; and/or

The width ratio between the polymer structure and the metal microstructure is 300: 1 to 1: 1.

7. The metal composite flexible substrate of claim 1, wherein the metal microstructures are arranged parallel to the polymer structure at the edge of the metal composite flexible substrate; and/or

The metal microstructures and the polymer structures at the edge of the metal composite flexible substrate are arranged in an inclined angle.

8. A method of making a metal composite flexible substrate according to any one of claims 1 to 7, comprising the steps of:

coating a polymer precursor solution on a substrate and drying to construct a polymer layer;

coating a photoresist on the polymer layer and drying to construct a photoresist layer;

placing a photolithographic reticle on the photoresist layer and exposing;

immersing the photoresist layer into a developing solution for patterning and drying to construct microstructure grooves, wherein the microstructure grooves and the polymer structures are arranged at intervals in a staggered mode;

constructing a metal seed layer on the microstructure groove and the photoresist layer;

removing the photoresist layer above the polymer layer and the metal seed layer above the polymer layer;

filling metal in the microstructure groove to construct a metal microstructure; and

and stripping the base to obtain the metal composite flexible substrate.

9. The method of claim 8, wherein the polymer precursor solution is applied or a photoresist is applied by spin coating; and/or

Constructing the metal seed layer by a magnetron sputtering method; and/or

And filling metal in the microstructure groove by an electroplating method.

10. A flexible resistive strain sensor having a metal composite flexible substrate according to any one of claims 1 to 7.

Technical Field

The present invention relates generally to the field of flexible substrate technology. Specifically, the invention relates to a metal composite flexible substrate and a preparation method thereof.

Background

Generally, the base of the flexible resistance-type strain sensor needs to use an isotropic organic material as a flexible substrate, and a sensitive structure of the flexible resistance-type strain sensor is mechanically deformed under the action of an external force so as to perform detection.

But the flexible substrate receives the ambient temperature change can take place expend with heat and contract with cold, therefore flexible resistance-type strain transducer is influenced by the heat comparatively obviously, and flexible substrate will transmit when being influenced by the temperature and taking place deformation and cause extra deformation for sensitive structure, and then influence resistance-type strain transducer in the detection accuracy of specific direction.

In view of the above problem that the isotropic thermal expansion variation potential of the flexible substrate caused by the environmental temperature affects the strain measurement of the flexible resistive strain sensor in a specific direction, a bridge is usually used in the prior art to realize temperature compensation. However, this method has problems that more sensors are required and the circuit matching design is complicated.

Disclosure of Invention

To at least partially solve the above problems in the prior art, the present invention proposes a metal composite flexible substrate comprising:

a polymer structure; and

metal microstructures in staggered spaced arrangement with the polymer structure;

the thicknesses of the polymer structure and the metal microstructure are the same, and the anisotropy and the controllability of the thermal expansion coefficient of the metal composite flexible substrate are determined by the widths of the polymer structure and the metal microstructure, the width ratio between the polymer structure and the metal microstructure and the arrangement direction of the polymer structure and the metal microstructure.

In one embodiment of the invention, it is provided that the metal microstructure comprises:

a microstructure groove;

the metal seed layer is positioned at the bottom of the microstructure groove; and

a filler metal filling the microstructure trenches.

In one embodiment of the invention, it is provided that the material of the polymer structure comprises polyimide.

In one embodiment of the invention, it is provided that the metal seed layer comprises a chromium metal layer and a copper metal layer; and/or

The material of the filler metal comprises copper.

In one embodiment of the invention, it is provided that the thickness of the polymer structure and the metal microstructure is 5 to 200 μm.

In one embodiment of the invention, it is provided that the width of the polymer structure is from 10 to 3000 μm; and/or

The width of the metal microstructure is 10-300 μm; and/or

The width ratio between the polymer structure and the metal microstructure is 300: 1 to 1: 1.

In one embodiment of the invention, the metal microstructures are arranged in parallel with the polymer structures at the edge of the metal composite flexible substrate; and/or

The metal microstructures and the polymer structures at the edge of the metal composite flexible substrate are arranged in an inclined angle.

The invention also provides a method for preparing the metal composite flexible substrate, which is characterized by comprising the following steps:

coating a polymer precursor solution on a substrate and drying to construct a polymer layer;

coating a photoresist on the polymer layer and drying to construct a photoresist layer;

placing a photolithographic reticle on the photoresist layer and exposing;

immersing the photoresist layer into a developing solution for patterning and drying to construct microstructure grooves, wherein the microstructure grooves and the polymer structures are arranged at intervals in a staggered mode;

constructing a metal seed layer on the microstructure groove and the photoresist layer;

removing the photoresist layer above the polymer layer and the metal seed layer above the polymer layer;

filling metal in the microstructure groove to construct a metal microstructure; and

and stripping the base to obtain the metal composite flexible substrate.

In one embodiment of the invention, it is provided that the polymer precursor solution is applied or the photoresist is applied by spin-on; and/or

Constructing the metal seed layer by a magnetron sputtering method; and/or

And filling metal in the microstructure groove by an electroplating method.

The invention also provides a flexible resistance type strain sensor which is provided with the metal composite flexible substrate.

The invention has at least the following beneficial effects:

the composite metal substrate with adjustable thermal expansion anisotropy is constructed by adding metal microstructures which are orderly arranged on the traditional flexible polymer.

The invention adopts MEMS technology to prepare the flexible metal composite substrate, and the substrate structure can comprise a polyimide film, a sputtered chromium metal thin layer and a copper metal thin layer, and an electroplated copper metal groove. The preparation method of the metal composite flexible substrate comprises the steps of modifying and modifying the interface between metal and polymer, and good, stable and reliable interface combination between a metal microstructure and a polymer structure can be realized through microstructure embedding and metal surface micro-nano processing modification.

According to the invention, the metal microstructure is embedded in the flexible polymer substrate, the composite flexible substrate is prepared by a simple and convenient process, and the substrate shows thermal expansion anisotropy and is adjustable and controllable, so that the flexible resistance-type strain sensor can get rid of the influence of extra deformation of the substrate caused by environmental temperature change, and the detection accuracy of the resistance-type strain sensor in a specific direction is ensured.

Drawings

To further clarify the advantages and features that may be present in various embodiments of the present invention, a more particular description of various embodiments of the invention will be rendered by reference to the appended drawings. It is appreciated that these drawings depict only typical embodiments of the invention and are therefore not to be considered limiting of its scope. In the drawings, the same or corresponding parts will be denoted by the same or similar reference numerals for clarity.

Fig. 1 and 2 respectively show a schematic structural diagram of a metal composite flexible substrate in an embodiment of the invention.

FIG. 3 shows a schematic flow chart of the preparation of a metal composite flexible substrate in one embodiment of the invention.

Detailed Description

It should be noted that the components in the figures may be exaggerated and not necessarily to scale for illustrative purposes. In the figures, identical or functionally identical components are provided with the same reference symbols.

In the present invention, "disposed on …", "disposed over …" and "disposed over …" do not exclude the presence of an intermediate therebetween, unless otherwise specified. Further, "disposed on or above …" merely indicates the relative positional relationship between two components, and may also be converted to "disposed below or below …" and vice versa in certain cases, such as after reversing the product direction.

In the present invention, the embodiments are only intended to illustrate the aspects of the present invention, and should not be construed as limiting.

In the present invention, the terms "a" and "an" do not exclude the presence of a plurality of elements, unless otherwise specified.

It is further noted herein that in embodiments of the present invention, only a portion of the components or assemblies may be shown for clarity and simplicity, but those of ordinary skill in the art will appreciate that, given the teachings of the present invention, required components or assemblies may be added as needed in a particular scenario. Furthermore, features from different embodiments of the invention may be combined with each other, unless otherwise indicated. For example, a feature of the second embodiment may be substituted for a corresponding or functionally equivalent or similar feature of the first embodiment, and the resulting embodiments are likewise within the scope of the disclosure or recitation of the present application.

It is also noted herein that, within the scope of the present invention, the terms "same", "equal", and the like do not mean that the two values are absolutely equal, but allow some reasonable error, that is, the terms also encompass "substantially the same", "substantially equal". By analogy, in the present invention, the terms "perpendicular", "parallel" and the like in the directions of the tables also cover the meanings of "substantially perpendicular", "substantially parallel".

The numbering of the steps of the methods of the present invention does not limit the order of execution of the steps of the methods. Unless specifically stated, the method steps may be performed in a different order.

The invention is further elucidated with reference to the drawings in conjunction with the detailed description.

Fig. 1 shows a schematic structural diagram of a metal composite flexible substrate in an embodiment of the present invention. As shown in fig. 1, the metal composite flexible substrate includes a polymer structure 101 and a metal microstructure 102.

The polymer structures 101 and the metal microstructures 102 are arranged in a staggered and spaced mode, the thicknesses of the polymer structures 101 and the metal microstructures 102 are the same, and the anisotropy and controllability of the thermal expansion coefficient of the metal composite flexible substrate can be determined through the widths of the polymer structures 101 and the metal microstructures 102, the width ratio between the polymer structures 101 and the metal microstructures 102 and the arrangement direction of the polymer structures 101 and the metal microstructures 102.

The thickness of the polymer structure 101 and the metal microstructure 102 may be 5-200 μm. The width of the polymer structure can be 10-3000 μm, the width of the metal microstructure can be 10-300 μm, and the width ratio between the polymer structure 101 and the metal microstructure 102 can be adjustable from 300: 1 to 1: 1. The metal microstructures 102 may be arranged in parallel with the polymer structure 101 at the edge of the metal composite flexible substrate as shown in fig. 1, or the metal microstructures 202 may be arranged at an oblique angle with the polymer structure 201 at the edge of the metal composite flexible substrate as shown in fig. 2.

The material of the polymer structure can be polyimide, and under the condition that no metal microstructure is added, the thermal expansion characteristics of the flexible substrate of the polymer material in all directions in a plane are consistent when the ambient temperature is increased, and isotropy is shown. In each embodiment of the invention, the metal microstructures and the polymer structure are constructed into a composite structure, and because the thermal expansion coefficient of metal is smaller than that of polymer, the polymer structure can freely expand along the vertical arrangement direction, but the expansion of the polymer structure along the arrangement direction is limited due to the restriction of the metal microstructures on two sides, so that the thermal expansion characteristic of the substrate in each direction in a plane is changed, and the metal composite flexible substrate shows the anisotropy of the thermal expansion coefficient. And the anisotropy of the thermal expansion coefficient can be further adjusted and controlled by adjusting the width, the width ratio and the arrangement direction of the metal microstructures and the polymer structures.

The metal microstructure may include a microstructure trench, a metal seed layer at a bottom of the microstructure trench, and a filler metal filling the microstructure trench. The metal seed layer may include a chromium metal layer and a copper metal layer, and the material of the filler metal may include copper.

The invention also provides a preparation method of the metal composite flexible substrate with adjustable and controllable thermal expansion anisotropy. The composite substrate is manufactured on the basis of a Micro Electro Mechanical System (MEMS) processing technology by adopting the processes of spin coating, photoetching, developing, magnetron sputtering, photoresist removal, electroplating and the like on a substrate at room temperature.

Specifically, as shown in fig. 3, in an embodiment of the present invention, a method for preparing the metal composite flexible substrate is further provided, including the following steps:

a polymer precursor solution is coated on the substrate 301 and dried to construct the polymer layer 302. Herein, the term "polymer precursor" refers to the form in which the polymeric material exists before curing. The substrate 301 may be a wafer substrate, quartz or glass, and the method for applying the polymer precursor solution may be a spin coating method.

A photoresist is coated on the polymer layer 302 and dried to construct a photoresist layer 303. The method in which the photoresist is applied may also be a spin coating method.

A photolithographic reticle is placed on the photoresist layer 303 and exposed.

The photoresist layer 303 is immersed in a developing solution to be patterned and dried to construct a plurality of microstructure grooves 305, wherein the plurality of microstructure grooves 305 are alternately arranged with a plurality of polymer structures.

A metal seed layer 304 is formed on the microstructure trenches and the photoresist layer 303, wherein the metal seed layer 304 may be formed by magnetron sputtering, and the metal seed layer 304 may include a chromium metal layer and a copper metal layer.

The photoresist layer 303 on the polymer layer 302 and the metal seed layer 304 thereon are removed.

The microstructure grooves are filled with a filler metal 306 by electroplating to form a metal microstructure, and the filler metal 306 may be copper.

And peeling the base 301 to obtain the metal composite flexible substrate.

The preparation method of the metal composite flexible substrate comprises the steps of modifying and modifying the interface between metal and polymer, and the interface can be well, stably and reliably combined with the substrate through micro-structure embedding and micro-nano processing modification on the surface of the metal.

While various embodiments of the present invention have been described above, it should be understood that they have been presented by way of example only, and not limitation. It will be apparent to persons skilled in the relevant art that various combinations, modifications, and changes can be made thereto without departing from the spirit and scope of the invention. Thus, the breadth and scope of the present invention disclosed herein should not be limited by any of the above-described exemplary embodiments, but should be defined only in accordance with the following claims and their equivalents.