KR-20260066397-A - Polymer Film Based Microphone Using a Two Dimensional Piezoelectric Material Layer and Method for Manufacturing the Same

KR20260066397AKR 20260066397 AKR20260066397 AKR 20260066397AKR-20260066397-A

Abstract

The present invention provides a method for fabricating a microphone and a method for manufacturing the same using a flexible polymer film having acoustic holes on its surface. Acoustic holes are formed in the polymer film through surface etching, and a two-dimensional piezoelectric material is transferred onto the film to maximize acoustic properties. Through the polymer film-based microphone utilizing a two-dimensional piezoelectric material layer according to the present invention, the acoustic holes can more effectively transmit vibrations of the piezoelectric material, thereby significantly improving the sensitivity and performance of the microphone.

Inventors

김상우
김소희
김대진
이현영
방 풍역

Assignees

연세대학교 산학협력단

Dates

Publication Date: 20260512
Application Date: 20241104

Claims (11)

A polymer substrate having a plurality of holes formed on its surface on one side; A two-dimensional piezoelectric material layer disposed on a surface of the polymer substrate where a hole is formed; and It includes an electrode layer disposed on the above-mentioned two-dimensional piezoelectric material layer, and Generating an electrical potential as the two-dimensional piezoelectric material layer vibrates due to sound pressure, Polymer film-based microphone using a two-dimensional piezoelectric material layer.
In Article 1, The above hole is formed in the above polymer through a surface etching process, Polymer film-based microphone using a two-dimensional piezoelectric material layer.
In Article 1, The above hole is a through hole, Polymer film-based microphone using a two-dimensional piezoelectric material layer.
In Article 1, The above two-dimensional piezoelectric material layer comprises two or more two-dimensional piezoelectric material layers stacked, and The above two or more two-dimensional piezoelectric material layers are different two-dimensional piezoelectric materials, Polymer film-based microphone using a two-dimensional piezoelectric material layer.
In Article 4, The above two or more two-dimensional piezoelectric material layers are formed by a co-sputtering method. Polymer film-based microphone using a two-dimensional piezoelectric material layer.
A step of forming a two-dimensional piezoelectric material layer on a substrate; A step of preparing a polymer layer and surface etching one side to form a plurality of holes; A step of transferring the two-dimensional piezoelectric material layer onto the surface of the polymer layer where holes are formed; and A step comprising forming an electrode on the above-mentioned two-dimensional piezoelectric material layer, Method for manufacturing a polymer film-based microphone using a two-dimensional piezoelectric material layer.
In Article 6, The step of forming a two-dimensional piezoelectric material layer on the above substrate is, Step of preparing the substrate; A step of depositing a two-dimensional material layer using a sputtering method; and A step comprising crystallizing the two-dimensional piezoelectric material layer through a heat treatment process, Method for manufacturing a polymer film-based microphone using a two-dimensional piezoelectric material layer.
In Article 7, In the step of stacking the above two-dimensional material layers, two or more two-dimensional piezoelectric material layers may be stacked, and the two or more two-dimensional piezoelectric material layers are different two-dimensional piezoelectric materials. When stacking two or more layers of two-dimensional piezoelectric material, using a co-sputtering method, Method for manufacturing a polymer film-based microphone using a two-dimensional piezoelectric material layer.
In Article 6, The above hole is a through hole, Method for manufacturing a polymer film-based microphone using a two-dimensional piezoelectric material layer.
In Article 6, The step of transferring the two-dimensional piezoelectric material layer onto the surface of the polymer layer where holes are formed is performed using a wet transfer process. Method for manufacturing a polymer film-based microphone using a two-dimensional piezoelectric material layer.
A polymer film-based microphone manufactured by a method for manufacturing a two-dimensional piezoelectric material layer according to any one of claims 6 to 10, Polymer film-based microphone using a two-dimensional piezoelectric material layer.

Description

Polymer Film Based Microphone Using a Two-Dimensional Piezoelectric Material Layer and Method for Manufacturing the Same The present invention relates to a polymer film-based microphone using a two-dimensional piezoelectric material layer. Specifically, the present invention relates to a polymer film-based two-dimensional piezoelectric microphone element structure in which acoustic properties are maximized through surface etching, and a method for fabricating the same. Generally, microphones operate using a dynamic method, which converts sound into electrical signals using coils and permanent magnets. However, this structure is difficult to miniaturize, limiting its integration into devices. Recently, semiconductor manufacturing processes utilizing Micro-Electro-Mechanical Systems (MEMS) have garnered attention, and methods for fabricating and integrating micro-microphones using silicon-based wafers are being employed. There is also a capacitive or condenser method. This method operates on the principle of detecting changes in capacitance through changes in the gap between two parallel plates (a fixed plate and a diaphragm). Condenser microphones must maintain a charge by applying a constant voltage, and high sensitivity can be achieved as the parallel plates become thinner, the gap between them narrower, and the applied voltage increases. However, if the diaphragm is too thin, its strength decreases, and if it is too thick, it breaks easily. If the gap between the two parallel plates is too narrow, it is vulnerable to external shocks or vibrations, and if the applied voltage is too high, the static deformation of the diaphragm increases, leading to problems such as reduced shock resistance and measurement range. Electret Condenser Microphones (ECM), which combine a condenser mechanism with an electret, utilize electrets—which store electrons semi-permanently—as the diaphragm or fixed plate. Since this method possesses permanent electrical polarization, it does not require a separate external power source. Although widely used in small mobile devices due to ease of manufacturing and low cost, it suffers from poor response characteristics and is difficult to operate at high temperatures because it uses polymers for the diaphragm. Piezoelectric microphones are manufactured using ceramic-based piezoelectric materials such as PZT (PbZr 1-x Ti x O 3 ), SBT (SrBi 2Ta 2 O 9 ), BLT (Bi 4-x La x Ti 3 O 12 ), PbTiO 3 , and BaTiO 3 , or film-type polymers with piezoelectric properties like PVDF (polyvinylidene fluoride). The use of piezoelectric materials allows for operation at low voltages and is advantageous for miniaturization and thin-film fabrication. However, acoustic output and sensitivity are lower compared to conventional microphones using coils and electromagnets. In particular, piezoelectric ceramics are brittle, and some are harmful to the human body. Ferroelectric polymers such as PVDF cannot be used at high temperatures and have lower piezoelectric properties than ceramics. Furthermore, heat treatment is required to form the β-phase of PVDF, which possesses piezoelectric properties, and an aging phenomenon occurs over time, resulting in a decrease in output. According to a previously filed patent (Patent Registration No. 10-1903420), a MEMS microphone device based on a two-dimensional piezoelectric material is constructed by forming a two-dimensional piezoelectric material on a substrate, depositing electrodes thereon, and then creating holes in the substrate through back-side etching. In this process, MoS₂ (or TMD-based materials) positioned in a suspended state on the substrate exhibits piezoelectric properties in the d- 11 direction, causing the electrodes to be arranged horizontally. However, this structure presents process difficulties because it requires additional semiconductor MEMS processes after the deposition of the two-dimensional material, and it has limitations due to a lack of flexibility inherent in Si wafer characteristics. In the present invention, an acoustic hole is formed on the surface of a flexible polymer film, after which a two-dimensional piezoelectric material is transferred and a metal is deposited to fabricate a two-dimensional piezoelectric microphone. This improves process efficiency and enables the realization of a flexible microphone. Figure 1 is a drawing of a two-dimensional piezoelectric material-based microphone structure according to Patent Registration No. 10-1903420. FIG. 2 illustrates a cross-sectional view of a polymer film-based microphone using a two-dimensional piezoelectric material layer with maximized acoustic properties through surface etching according to one embodiment of the present invention. FIG. 3 illustrates a flowchart of a method for manufacturing a polymer film-based microphone using a two-dimensional piezoelectric material layer according to one embodiment of the present invention. FIG. 4 illustrates a schematic diagram of a method for manufact