CN116170906A

CN116170906A - A kind of MEMS microheater of supporting beam and its manufacturing method

Info

Publication number: CN116170906A
Application number: CN202211559639.4A
Authority: CN
Inventors: 张韬; 潘泽权; 张春华; 熊流广; 王宇航; 张健
Original assignee: Northeast Forestry University
Current assignee: Northeast Forestry University
Priority date: 2022-12-06
Filing date: 2022-12-06
Publication date: 2023-05-26

Abstract

A MEMS micro-heater of a supporting beam and a manufacturing method thereof belong to the technical field of MEMS. The supporting beam is used for absorbing thermal stress and external vibration, meanwhile, the temperature uniformity is improved, and the service life of the heater is prolonged. The MEMS microheater includes: a silicon-based substrate; the heat insulation layer is used for reducing heat loss of the MEMS heater due to heat conduction; the insulating layer improves the temperature uniformity of the heating area through the heat conduction effect; the heating resistor is positioned above the heat insulation layer; and the isolating layer is completely covered above the heating resistor. The manufacturing method comprises the following steps: s1, etching a silicon-based substrate to form a supporting beam, an outer frame and a heating platform; s2, forming heat insulation layers on the upper surface and the lower surface of the silicon-based substrate; s3, forming an insulating layer on the insulating layer; s4, forming a heating resistor on the insulating layer; s5, forming an isolation layer to cover the heating resistor. The heating zone is suspended in the air through the supporting beams around, so that heat loss is reduced, and meanwhile, internal thermal stress is absorbed through deformation of the supporting beams.

Description

MEMS micro-heater of supporting beam and manufacturing method thereof

Technical Field

The invention belongs to the technical field of MEMS, and particularly relates to an MEMS micro-heater of a supporting beam and a manufacturing method thereof.

Background

Micro-heaters fabricated based on MEMS technology are commonly used heating platforms for heating materials or elements on the platform to a certain temperature condition. Because MEMS micro-heaters have the advantages of low power consumption, high response speed, small volume, mass production, easy integration and the like, the MEMS micro-heaters are widely used for micro-gas sensors, micro-drivers, micro-accelerometers, micro-infrared light sources and the like.

The basic structure of MEMS micro-heaters includes a mechanical support structure and a thin film resistor. The film resistor is distributed on the heating platform to play a role in heating or temperature measurement.

In the prior art, in order to improve the response speed of the heater and reduce the heat loss, a suspension film structure is generally adopted, and the suspension film is connected to a support substrate through a support cantilever. Therefore, the mechanical property of the structure is poor, the suspended film is easy to break, so that the performances of the heater such as vibration resistance and the like are weak, and the application range of the heater is limited. The temperature distribution is uneven in the using process of the heater, so that the thermal stress in the heater is larger, the rupture of the film is further aggravated, and the service life of the heater is reduced.

Disclosure of Invention

The invention aims to solve the problems, and further provides a MEMS micro-heater of a supporting beam and a manufacturing method thereof, wherein the supporting beam is used for absorbing thermal stress and external vibration, meanwhile, the temperature uniformity is improved, and the service life of the heater is prolonged.

The technical scheme adopted by the invention is as follows:

a MEMS micro-heater for a support beam, comprising

A silicon-based substrate,

the heat insulation layers are positioned on the upper surface and the lower surface of the silicon substrate and are used for reducing the heat loss of the MEMS heater due to heat conduction;

the insulating layer is positioned on the upper surface of the heat insulating layer to play an insulating role, and meanwhile, the temperature uniformity of a heating area is improved through a heat conduction role;

the heating resistor is positioned above the insulating layer;

and the isolating layer is completely covered above the heating resistor and is used for windowing at the electrode position of the heating resistor.

A method of manufacturing a MEMS micro-heater comprising the steps of:

s1, etching a silicon-based substrate to form a supporting beam, an outer frame and a heating platform;

s2, growing SiO on the upper surface and the lower surface of the silicon-based substrate ₂ A film forming a heat insulating layer;

s3, forming an insulating layer on the upper surface of the insulating layer by a plasma enhanced chemical vapor deposition method;

s4, processing a heating resistor on the surface of the insulating layer by adopting a targeted sputtering process;

s5, growing an isolation layer by a plasma enhanced chemical vapor deposition method, and completely covering the heating resistor.

Compared with the prior art, the invention has the following beneficial effects:

1. the heating area is suspended in the air through the supporting beams around, so that heat loss is reduced, meanwhile, internal thermal stress is absorbed through deformation of the supporting beams, and deformation and warping of the heating area during high-temperature operation are avoided.

2. According to the invention, heat loss is reduced by arranging the heat insulation layer, and the power consumption of the MEMS micro-heater is reduced.

3. The invention has simple structure, reduces manufacturing procedures and manufacturing difficulty, and can be used for mass production.

Drawings

FIG. 1 is a schematic cross-sectional view of the present invention.

FIG. 2 is a schematic top view of a silicon-based substrate according to the present invention.

FIG. 3 is a schematic diagram of the heating resistor according to the present invention.

Fig. 4 is a process flow diagram of a MEMS micro-heater.

Wherein: 1. a silicon-based substrate; 2. a thermal insulation layer; 3. an insulating layer; 4. a heating resistor; 5. an isolation layer; 6. a support beam; 7. an outer frame; 8. and heating the platform.

Detailed Description

For a better understanding of the objects, structures and functions of the present invention, reference should be made to the following detailed description of the invention with reference to the accompanying drawings.

Referring to FIGS. 1 to 3, a MEMS micro-heater of a support beam of the present invention comprises

The silicon-based substrate 1 can adopt n-type monocrystalline silicon with the (100) crystal orientation, the thickness is 200-500 mu m, and the two sides of the silicon-based substrate 1 are polished.

The heat insulation layer 2 is positioned on the upper surface and the lower surface of the silicon-based substrate 1 and is made of SiO ₂ The thin film is manufactured by a Plasma Enhanced Chemical Vapor Deposition (PECVD) method, and the thickness is 50-500 nm. The heat loss of the MEMS heater due to heat conduction is reduced, and the power consumption of the device is reduced;

an insulating layer 3 formed on the upper surface of the insulating layer 2 and made of a high heat conductive insulating material (Si ₃ N ₄ Or Al ₂ O ₃ ) The thin film is manufactured by a Plasma Enhanced Chemical Vapor Deposition (PECVD) method, and the thickness is 50-500 nm. The edge of the insulating layer 3 is completely aligned with the heating platform 8, the insulating layer 3 can prevent the heating resistor 4 from being in direct contact with the silicon-based substrate 1, so that the insulating effect can be achieved, and meanwhile, the temperature uniformity of a heating area is improved through the high heat conduction characteristic of the material; the insulating layer 3 can also be formed of SiO with the underlying insulating layer 2 ₂ And forming a composite material layer, and reducing the thermal stress in the heating process.

A heating resistor 4 located above the insulating layer 3; the material is a high-temperature-resistant metal material such as platinum, tungsten and the like which can be well compatible with MEMS technology. The thickness of the heating resistor 4 is 50-500 nm by a radio frequency magnetron sputtering method and a stripping method, and the heating resistor 4 adopts a spiral surrounding structure so as to uniformly heat the heating platform 8. When the heating resistor 4 is made of a material with stable resistivity temperature coefficient such as platinum, the material can be used as a temperature measuring resistor of the MEMS micro-heater.

An isolation layer 5 for preventing heating of electricity during operationThe resistor 4 is in direct contact with other objects, an isolating layer 5 is covered on the surface of the heating resistor 4, and a window is formed at the electrode position of the heating resistor 4. The edges of the insulating layer 5 are perfectly aligned with the edges of the heating platform 8. The material of the isolation layer 5 is Si with high heat conductivity ₃ N ₄ Or Al ₂ O ₃ The thickness is 100-300 nm.

The silicon-based substrate 1 is etched by a deep reactive ion etching technology to form three areas of a supporting beam 6, an outer frame 7 and a heating platform 8,

a heating stage 8 located in the middle of the silicon-based substrate 1 as a heating region and a sample mounting region of the device;

the supporting beam 6 is positioned around the heating platform 8, a certain gap is arranged between the supporting beam 6 and the heating platform 8, and the gap size is 50-200 mu m. A certain gap is arranged between the supporting beam 6 and the outer frame 7, and the size of the gap is 50-200 mu m. Absorbing thermal stress of the heating area due to high temperature by deformation of the support beam 6; the width of the supporting beam 6 is 100-1000 mu m, the shape of the supporting beam 6 is one of a strip shape, an arc shape or a V shape, the supporting beam 6 reduces the contact area between a heating area and the outside, the heat insulation effect can be achieved, and the temperature uniformity of the heating area is improved. The supporting beams 6 are of symmetrical structures, so that the impact resistance of the device can be improved.

The outer frame 7 is connected with the heating platform 8 through the supporting beam 6, and plays a role in supporting and fixing.

As shown in fig. 4, a method for manufacturing a MEMS micro-heater according to the present invention includes the steps of:

s1, preparing a clean double-polished monocrystalline silicon wafer as a silicon substrate 1, and processing a groove with a preset shape on the silicon substrate 1 by a deep reactive ion etching technology to form a supporting beam 6, an outer frame 7 and a heating platform 8;

s2, growing SiO on the upper surface and the lower surface of the silicon substrate 1 by a Plasma Enhanced Chemical Vapor Deposition (PECVD) method ₂ A film forming a heat insulating layer 2;

s3, forming an insulating layer 3 on the upper surface of the insulating layer 2, namely, forming a silicon oxide film on the upper surface of the insulating layer by a Plasma Enhanced Chemical Vapor Deposition (PECVD) method ₂ Growth of Si on the upper surface ₃ N ₄ Film formationAn insulating layer 3;

s4, processing a heating resistor 4 on the surface of the insulating layer by adopting a targeted sputtering process; the method comprises the following steps: and processing the shape and the position of the heating resistor 4 on the surface of the insulating layer 3 through photoresist homogenizing lithography, depositing a layer of metal platinum through magnetron sputtering to form the heating resistor 4, and removing the residual photoresist through a stripping process.

S5, growing the isolation layer 5 by a Plasma Enhanced Chemical Vapor Deposition (PECVD), namely depositing a layer of Al on the upper surface of the heating platform 8 by the Plasma Enhanced Chemical Vapor Deposition (PECVD) ₂ O ₃ An isolation layer is formed to entirely cover the heating resistor 4.

It will be understood that the invention has been described in terms of several embodiments, and that various changes and equivalents may be made to these features and embodiments by those skilled in the art without departing from the spirit and scope of the invention. In addition, many modifications may be made to adapt a particular situation or material to the teachings of the invention without departing from the essential scope thereof. Therefore, it is intended that the invention not be limited to the particular embodiment disclosed, but that the invention will include all embodiments falling within the scope of the appended claims.

Claims

1. a kind of MEMS microheater of support beam, it is characterized in that: comprise

silicon-based substrate (1),

The heat insulating layer (2), located on the upper and lower surfaces of the silicon-based substrate (1), is used to reduce the heat lost by the MEMS heater due to heat conduction;

The insulation layer (3) is located on the upper surface of the heat insulation layer (2) to play an insulating role, and at the same time, through heat conduction, the temperature uniformity of the heating area is improved;

The heating resistor (4) is located above the insulating layer (3);

The isolation layer (5) completely covers the heating resistor (4), and a window is opened at the electrode position of the heating resistor (4).

2. the MEMS microheater of a kind of support beam according to claim 1 is characterized in that: form support beam (6), outer frame (7) and heating platform (8) by etching silicon-based substrate (1) ) three areas,

The heating platform (8), located in the middle of the silicon-based substrate (1), serves as the heating area of the device and the sample loading area;

The support beam (6), located around the heating platform (8), absorbs the thermal stress caused by the high temperature in the heating area through the deformation of the support beam (6);

The outer frame (7) is connected with the heating platform (8) through the support beam (6) to play a role of support and fixation.

3. The MEMS micro-heater supporting a beam according to claim 1, characterized in that: the silicon-based substrate (1) adopts n-type single crystal silicon with (100) crystal orientation, and the thickness is 200-500 μm , both sides of the silicon-based substrate (1) are polished.

4. A kind of MEMS micro-heater supporting the beam according to claim 1, characterized in that: the material of the heat insulating layer (2) is SiO ₂ , manufactured by plasma enhanced chemical vapor deposition, with a thickness of 50- 500nm.

5. The MEMS micro-heater of a kind of support beam according to claim 1, it is characterized in that: described insulating layer (3) adopts high thermal conductivity insulating material, is manufactured by plasma-enhanced chemical vapor deposition method, and thickness is 50～ 500nm.

6. A kind of MEMS micro-heater supporting a beam according to claim 1, characterized in that: the material of the heating resistor (4) is a high temperature resistant metal with a thickness of 50-500nm, and the heating resistor (4) adopts a spiral Surrounding the structure, so that the heating platform (8) is evenly heated.

7 . The MEMS micro heater supporting a beam according to claim 2 , characterized in that there is a certain gap between the supporting beam ( 6 ) and the outer frame ( 7 ), and the size of the gap is 50-200 μm.

8 . The MEMS micro heater supporting a beam according to claim 2 , characterized in that there is a certain gap between the supporting beam ( 6 ) and the heating platform ( 8 ), and the size of the gap is 50-200 μm.

9. A method for manufacturing a MEMS micro heater, characterized in that: comprising the following steps:

S1. Etching a support beam (6), an outer frame (7) and a heating platform (8) on a silicon-based substrate (1);

S2. grow _SiO2 thin films on the upper and lower surfaces of the silicon-based substrate (1) to form a thermal insulation layer (2);

S3. forming an insulating layer (3) on the upper surface of the heat insulating layer (2) by plasma enhanced chemical vapor deposition;

S4. Process the heating resistor (4) on the surface of the insulating layer by using a targeted sputtering process;

S5. Growing the isolation layer (5) by plasma-enhanced chemical vapor deposition.

10. The manufacturing method of a MEMS micro-heater according to claim 9, characterized in that: said S4 is specifically: process a heating resistor (4) on the surface of said insulating layer (3) by uniform photolithography The shape and position of the heating resistor (4) is formed by depositing a layer of metal platinum by magnetron sputtering, and the remaining photoresist is removed by a stripping process.