A transmission electron microscope high-resolution in-situ temperature difference pressurization chip and its preparation method

Abstract

The invention relates to a transmission electron microscope high-resolution in-situ temperature difference pressurization chip and a preparation method thereof, wherein the chip comprises a substrate covered with an insulating layer on both sides, and two heating and pressurization units arranged in left and right mirror images are arranged on the front side of the substrate; each heating and pressurization unit comprises two heating electrodes, a pressurization electrode, a heating wire and a pressurization circuit, the heating wire and the pressurization circuit are arranged in the middle of the substrate to form a heating and pressurization area, a gap is provided between the heating and pressurization areas of the two heating and pressurization units, the heating wire is respectively connected to the two heating electrodes through two heating circuits, the pressurization circuit is connected to the pressurization electrode through a pressurization circuit, and other areas on the substrate except for supporting the heating and pressurization unit, the two heating circuits and the pressurization circuit are hollowed out, and the chip can simultaneously realize the temperature difference pressurization function.

Description

Technical Field

[0001] The invention relates to the field of in-situ characterization, and in particular to a transmission electron microscope high-resolution in-situ temperature difference pressurization chip and a preparation method thereof. Background Art

[0002] In-situ transmission electron microscopy technology is widely used in various scientific fields due to its advantages of ultra-high spatial resolution (atomic level) and ultra-fast time resolution (millisecond level), which provides researchers with new ideas and research methods for exploring the microstructure of new materials. It is mainly manifested in building a visual window in the electron microscope, introducing external fields such as thermal field, light field, and electrochemical field, and conducting real-time dynamic in-situ tests on samples. Researchers can capture the dynamic sensing of samples to the environment through in-situ testing technology, including important information such as size, morphology, crystal structure, atomic structure, chemical bond, and thermal energy changes. The morphological changes of materials at the atomic scale under the action of external fields have become the foundation of material research and development. It can be widely used in microstructure analysis, observation of nanomaterial research, etc., and has extremely high application value in biology, materials, and semiconductor electronic materials.

[0003] At present, the chip structures that realize the temperature difference function for micron-level materials include suspension type and bridge type. The bridge method is to place the sample between two heating wires, with the two ends used for heating and temperature measurement respectively. Under heating or force conditions, the cantilever beam is easily damaged; although the suspension structure has high accuracy and can measure materials with a size of tens of nanometers, there is no hollow structure between the two heating units, the insulation effect is not ideal, there may be a certain temperature error, and the heating and temperature measurement of the sample require two different circuits to achieve. If the temperature difference pressurization function is to be realized at the same time, the current chip structure still needs to be improved in terms of accuracy and stability. Summary of the invention

[0004] The present invention aims to provide a transmission electron microscope high-resolution in-situ temperature difference pressurization chip which can simultaneously realize the temperature difference pressurization function.

[0005] The specific plan is as follows:

[0006] A high-resolution in-situ temperature difference pressurization chip for a transmission electron microscope comprises a substrate covered with an insulating layer on both sides, wherein two heating and pressurization units arranged in a left-right mirror image are arranged on the front side of the substrate; each heating and pressurization unit comprises two heating electrodes, a pressurization electrode, a heating wire and a pressurization circuit, wherein the two heating electrodes and the pressurization electrode are distributed on the same side edge of the substrate; the heating wire and the pressurization circuit are arranged in the middle of the substrate to form a heating and pressurization area, and there is a gap between the heating and pressurization areas of the two heating and pressurization units; the heating wire is respectively connected to the two heating electrodes through two heating circuits, and the pressurization circuit is connected to the pressurization electrode through a pressurization circuit, and the other areas on the substrate except for the areas used to support the heating and pressurization units, the two heating circuits and the pressurization circuit are hollowed out.

[0007] Preferably, the two heating circuits and one pressurizing circuit of each heating and pressurizing unit are respectively located on a cantilever, the three cantilevers are arranged in a "T" shape, and the heating wire is arranged at the intersection of the three cantilevers.

[0008] Preferably, the pressurizing circuit is closer to the gap than the heating wire.

[0009] Preferably, the heating wire and the two heating electrodes connected thereto form an equivalent circuit, and the equivalent circuit can simultaneously realize power supply and heating of the heating wire and real-time monitoring of the resistance value of the heating wire after heating.

[0010] Preferably, the substrate is a silicon substrate, and the insulating layer is a silicon nitride or silicon oxide insulating layer.

[0011] Preferably, the transmission electron microscope high-resolution in-situ temperature difference pressurization chip has a chip size of 2mm*2mm-10mm*10mm or 4mm*6mm.

[0012] Preferably, the thickness of the insulating layer on the front and back sides of the substrate is 5-200 nm, and the thickness of the substrate is 50-500 um.

[0013] Preferably, the size of the gap is 0.002mm*3.0mm-0.01mm*3.5mm.

[0014] Preferably, the size of the heating and pressurizing zone is 0.2mm*0.2mm-0.5mm*0.5mm; the size of the cantilever is 0.5mm*0.2mm-1.5mm*0.5mm.

[0015] The present invention also provides a method for preparing a transmission electron microscope high-resolution in-situ temperature difference pressurization chip, comprising the following steps:

[0016] S1. Prepare a Si(100) wafer A having a silicon nitride or silicon oxide insulating layer on both the front and back sides, the thickness of the insulating layer being 5-200 nm;

[0017] S2. Transferring the patterns of the heating electrode, the voltage electrode, the heating wire, the voltage circuit, the heating line connecting the heating wire and the heating electrode, and the voltage line connecting the voltage circuit and the voltage electrode from the photolithography mask to the front side of the wafer A through a photolithography process, then developing the pattern in a positive photoresist developer, and then cleaning the surface with deionized water to obtain a wafer A-1;

[0018] S3. The exposed silicon nitride or silicon oxide insulating layer on the front side of the wafer A-1 is etched away by a reactive ion etching process, and then the wafer is immersed in acetone with the front side facing up, and finally rinsed with acetone to remove the photoresist to obtain a wafer A-2;

[0019] S4. Using electron beam evaporation coating process, a layer of metal film is evaporated on the front side of wafer A-2 to form heating electrodes, pressure electrodes, heating wires, pressure circuits, heating lines and pressure lines, and then the wafer is placed in acetone with the front side facing up for immersion and peeling, and finally rinsed with deionized water to remove the photoresist, leaving the metal layer, and obtaining wafer A-3;

[0020] S5. Using a PECVD process, a layer of silicon nitride, silicon oxide or aluminum oxide is grown on the front side of the wafer A-3 as a protective layer to obtain a wafer A-4;

[0021] S6. Using a photolithography process, the area to be etched is transferred from the photolithography mask to the back of the wafer A-4, then developed in a positive photoresist developer, and then the surface is cleaned with deionized water to obtain a wafer A-5;

[0022] S7. Using a reactive ion etching process, the silicon nitride or silicon oxide on the back of the wafer A-5 to be etched is etched away, and then the back of the wafer is placed in acetone and immersed, and finally rinsed with acetone to remove the photoresist to obtain a wafer A-6;

[0023] S8. Place the back side of wafer A-6 facing upward into a potassium hydroxide solution for wet etching until the exposed substrate silicon is completely etched, remove the wafer, rinse it with a large amount of deionized water, and blow dry it to obtain wafer A-7;

[0024] S9. The exposed silicon nitride, silicon oxide or aluminum oxide protective layer on the front side of the wafer A-7 is etched away by a reactive ion etching process, and then the wafer is immersed in acetone with the front side facing up, and finally rinsed with acetone to remove the photoresist, thereby obtaining a wafer A-8;

[0025] S10. Laser-slice wafer A-8 into independent chips.

[0026] The transmission electron microscope high-resolution in-situ temperature difference pressurization chip provided by the present invention has the following advantages compared with the prior art: the heating wire of the transmission electron microscope high-resolution in-situ temperature difference pressurization chip provided by the present invention only needs to be connected to two electrodes to form a loop, and the temperature measurement and temperature control functions can be realized at the same time, so the two ends can measure and control the temperature at the same time; and in addition to applying different temperatures to the two ends of the carried sample, the temperature difference pressurization chip can also apply different voltages to the sample, and can study solid materials under two external field stimuli of different temperatures and voltages; and the supporting layer where the connection line between the heating wire, the pressurization circuit and the contact electrode is located is a T-shaped structure, which is more stable than the separate cantilever beam structure at the two ends of the existing temperature difference chip, and the temperature difference pressurization chip also has the advantages of rapid temperature rise and fall, precise temperature control and temperature measurement, simultaneous temperature difference and pressurization, high resolution, and low sample drift rate. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 A top view of the transmission electron microscope high-resolution in-situ temperature differential pressurization chip is shown.

[0028] Figure 2 Shows Figure 1 Cross-sectional view at AA in the middle.

[0029] Figure 3 Shows Figure 1 Cross-sectional view at BB in the middle.

[0030] Figure 4 Shows Figure 1 Enlarged view of the heated and pressed area. DETAILED DESCRIPTION

[0031] To further illustrate the various embodiments, the present invention provides drawings. These drawings are part of the disclosure of the present invention, which are mainly used to illustrate the embodiments and can be used in conjunction with the relevant descriptions in the specification to explain the operating principles of the embodiments. With reference to these contents, a person of ordinary skill in the art should be able to understand other possible implementations and advantages of the present invention. The components in the figures are not drawn to scale, and similar component symbols are generally used to represent similar components.

[0032] The present invention will now be further described with reference to the accompanying drawings and specific implementation methods.

[0033] Example 1

[0034] like Figure 1-Figure 4 As shown, this embodiment provides a transmission electron microscope high-resolution in-situ temperature difference pressurization chip, including a substrate 1, the front and back sides of the substrate 1 are covered with an insulating layer 10. The substrate in this embodiment is a silicon substrate, and the insulating layer is a silicon nitride or silicon oxide insulating layer.

[0035] Two heating and pressing units 11 are arranged in a left-right mirror image on the front side of the substrate 1. Each heating and pressing unit 11 includes two heating electrodes 111, a pressing electrode 112, an arc-shaped heating wire 113 and a pressing circuit 114, wherein the two heating electrodes 111 and the pressing electrode 112 are distributed on the same side edge of the substrate; the arc-shaped heating wire 113 and the pressing circuit 114 are arranged in the middle of the substrate 1 and form a heating and pressing area, and there is a gap 12 between the heating and pressing areas of the two heating and pressing units 11, and the gap 12 is used to place the sample, and the heating and pressing areas of the two heating and pressing units 11 do not contact each other.

[0036] The heating wire 113 is connected to the two heating electrodes 111 respectively through two heating circuits 115 , and the pressurizing circuit 114 is connected to the pressurizing electrode 112 through a pressurizing circuit 116 .

[0037] The substrate 1 has its base material and the insulating layers on its front and back surfaces removed from other areas except for the areas used to support the heating and pressing unit 11 , the two heating circuits 115 and the one pressing circuit 116 , thereby forming a hollow state.

[0038] In this embodiment, the two heating circuits 115 and the one pressurizing circuit 116 of each heating and pressurizing unit 11 are respectively located on a cantilever 13 , the three cantilevers 13 are arranged in a “T” shape, and the heating wire 113 is arranged at the intersection of the three cantilevers 13 .

[0039] In this embodiment, the pressure circuit 114 is closer to the gap 12 than the heating wire 113 .

[0040] In this embodiment, each heating wire 113 and the two heating electrodes 111 connected thereto form an equivalent circuit, which can simultaneously realize power supply and heating of the heating wire and real-time monitoring of the resistance value of the heating wire after heating.

[0041] In this embodiment, the chip size of the transmission electron microscope high-resolution in-situ temperature difference pressurization chip is 2mm*2mm-10mm*10mm; preferably, the chip size is 4mm*6mm.

[0042] In this embodiment, the thickness of the insulating layer on the front and back sides of the substrate 1 is 5-200 nm.

[0043] In this embodiment, the thickness of the substrate 1 is 50-500 um.

[0044] In this embodiment, the size of the heating and pressing zone is 0.2mm*0.2mm-0.5mm*0.5mm; the size of the cantilever is 0.5mm*0.2mm-1.5mm*0.5mm; the size of the gap between the two heating and pressing zones is 0.002mm*3.0mm-0.01mm*3.5mm.

[0045] In this embodiment, the size of the heating wire is 0.15mm*0.5mm-0.15mm*0.5mm; the size of the pressure circuit is 0.01mm*0.05mm-0.02mm*0.1mm, and the thickness is 50nm-500nm;

[0046] In this embodiment, the heating wire 113 is made of metal gold, platinum, palladium, rhodium, molybdenum, tungsten, platinum-rhodium alloy or non-metallic molybdenum carbide.

[0047] The heating wire of the transmission electron microscope high-resolution in-situ temperature difference pressurization chip provided in this embodiment only needs to connect two electrodes to form a loop, and can realize the temperature measurement and temperature control functions at the same time, so the two ends can measure and control the temperature at the same time. In addition to applying different temperatures to the two ends of the sample carried, the temperature difference pressurization chip can also apply different voltages to the sample, and can study solid materials under two external field stimuli of different temperatures and voltages; and the support layer where the connection line between the heating wire, the pressurization circuit and the contact electrode is located is a T-shaped structure, which is more stable than the separate cantilever beam structure at both ends of the existing temperature difference chip, and the temperature difference pressurization chip also has the advantages of rapid temperature rise and fall, precise temperature control and temperature measurement, simultaneous temperature difference and pressurization, high resolution, and low sample drift rate.

[0048] Example 2

[0049] This embodiment provides a method for preparing a transmission electron microscope high-resolution in-situ temperature difference pressurization chip, comprising the following steps:

[0050] S1. Prepare a Si (100) wafer A having a silicon nitride or silicon oxide insulating layer on both the front and back sides, the thickness of the insulating layer is 5-200 nm, and the silicon nitride or silicon oxide insulating layer on the front and back sides of the wafer A can be achieved by low-pressure chemical vapor deposition;

[0051] S2. Transferring the patterns of the heating electrode, the voltage electrode, the heating wire, the voltage circuit, the heating line connecting the heating wire and the heating electrode, and the voltage line connecting the voltage circuit and the voltage electrode from the photolithography mask to the front side of the wafer A through a photolithography process, then developing the pattern in a positive photoresist developer, and then cleaning the surface with deionized water to obtain a wafer A-1;

[0052] Preferably, the photolithography process is performed in a hard contact mode of an ultraviolet photolithography machine; the photoresist in the photolithography process is AZ5214E; and the development time is 50 seconds;

[0053] More preferably, the exposure time is 15 s;

[0054] S3. The exposed silicon nitride or silicon oxide insulating layer on the front side of the wafer A-1 is etched away by a reactive ion etching process, and then the wafer is immersed in acetone with the front side facing up, and finally rinsed with acetone to remove the photoresist to obtain a wafer A-2;

[0055] S4. Using electron beam evaporation coating process, a layer of metal film is evaporated on the front side of wafer A-2 to form heating electrodes, pressure electrodes, heating wires, pressure circuits, heating lines and pressure lines, and then the wafer is placed in acetone with the front side facing up for immersion and peeling, and finally rinsed with deionized water to remove the photoresist, leaving the metal layer, and obtaining wafer A-3;

[0056] Preferably, the material of the heating wire is metal gold, platinum, palladium, rhodium, molybdenum, tungsten, platinum-rhodium alloy or non-metallic molybdenum carbide; the thickness of the metal heating wire is 50-500nm;

[0057] S5. Using a PECVD process, a layer of silicon nitride, silicon oxide or aluminum oxide is grown on the front side of the wafer A-3 as a protective layer to obtain a wafer A-4;

[0058] Preferably, the thickness of the protective layer is 30-150 nm;

[0059] S6. Using a photolithography process, the area to be etched is transferred from the photolithography mask to the back of the wafer A-4, then developed in a positive photoresist developer, and then the surface is cleaned with deionized water to obtain a wafer A-5;

[0060] Preferably, the photolithography process is exposure in the hard contact mode of the ultraviolet photolithography machine; the photoresist used in the photolithography process is AZ5214E; the development time is 65s;

[0061] More preferably, the exposure time is 20 s;

[0062] S7. Using a reactive ion etching process, the silicon nitride or silicon oxide on the back of the wafer A-5 to be etched is etched away, and then the back of the wafer is placed in acetone and immersed, and finally rinsed with acetone to remove the photoresist to obtain a wafer A-6;

[0063] S8. Place the back side of wafer A-6 facing upward into a potassium hydroxide solution for wet etching until the exposed substrate silicon is completely etched, remove the wafer, rinse it with a large amount of deionized water, and blow dry it to obtain wafer A-7;

[0064] Preferably, the mass percentage concentration of the potassium hydroxide solution is 20%; the etching temperature is 70-90° C., and the etching time is 1.5-4 hours;

[0065] More preferably, the etching temperature is 80° C. and the etching time is 2 h;

[0066] Preferably, the size of the silicon support layer in the heating zone is 0.2mm*0.2mm-0.5mm*0.5mm; the size of the cantilever between the contact electrode and the heating zone is 0.5mm*0.2mm-1.5mm*0.5mm; the size of the gap between the two heating zones is 0.002mm*3.0mm-0.01mm*3.5mm;

[0067] S9. The exposed silicon nitride, silicon oxide or aluminum oxide protective layer on the front side of the wafer A-7 is etched away by a reactive ion etching process, and then the wafer is immersed in acetone with the front side facing up, and finally rinsed with acetone to remove the photoresist, thereby obtaining a wafer A-8;

[0068] S10. Laser-slice wafer A-8 into independent chips.

[0069] Although the present invention has been specifically shown and described in conjunction with the preferred embodiments, it should be understood by those skilled in the art that various changes may be made to the present invention in form and details without departing from the spirit and scope of the present invention as defined by the appended claims, all of which are within the scope of protection of the present invention.

Claims

1. A high-resolution in-situ temperature difference pressurization chip for transmission electron microscopy, characterized in that: It comprises a substrate covered with an insulating layer on both sides, and two heating and pressing units arranged in a left and right mirror image are arranged on the front side of the substrate; each heating and pressing unit comprises two heating electrodes, a pressing electrode, a heating wire and a pressing circuit, wherein the two heating electrodes and the pressing electrode are distributed on the same side edge of the substrate; the heating wire and the pressing circuit are arranged in the middle of the substrate to form a heating and pressing area, and there is a gap between the heating and pressing areas of the two heating and pressing units; the heating wire is connected to the two heating electrodes respectively through two heating circuits, and the pressing circuit is connected to the pressing electrode through a pressing circuit, and the other areas on the substrate except for the areas used to support the heating and pressing units, the two heating circuits and the pressing circuit are hollowed out; Two heating circuits and one pressurizing circuit of each heating and pressurizing unit are respectively located on a cantilever; The pressurizing circuit is closer to the gap than the heating wire.

2. The transmission electron microscope high-resolution in-situ temperature difference pressurization chip according to claim 1, characterized in that: The three cantilevers of each heating and pressurizing unit are arranged in a "T" shape, and the heating wire is arranged at the intersection of the three cantilevers.

3. The transmission electron microscope high-resolution in-situ temperature difference pressurization chip according to claim 1, characterized in that: The heating wire and the two heating electrodes connected thereto form an equivalent circuit, which can simultaneously realize power supply heating to the heating wire and real-time monitoring of the resistance value of the heating wire after heating.

4. The transmission electron microscope high-resolution in-situ temperature difference pressurization chip according to claim 1, characterized in that: The substrate is a silicon substrate, and the insulating layer is a silicon nitride or silicon oxide insulating layer.

5. The transmission electron microscope high-resolution in-situ temperature difference pressurization chip according to claim 1, characterized in that: The chip size of the transmission electron microscope high-resolution in-situ temperature difference pressurization chip is 2mm*2mm-10mm*10mm or 4mm*6mm.

6. The transmission electron microscope high-resolution in-situ temperature difference pressurization chip according to claim 1, characterized in that: The thickness of the insulating layer on the front and back sides of the substrate is 5-200nm, and the thickness of the substrate is 50-500um.

7. The transmission electron microscope high-resolution in-situ temperature difference pressurization chip according to claim 1, characterized in that: The size of the gap is 0.002mm*3.0mm-0.01mm*3.5mm.

8. The transmission electron microscope high-resolution in-situ temperature difference pressurization chip according to claim 2, characterized in that: The size of the heating and pressurizing zone is 0.2mm*0.2mm-0.5mm*0.5mm; the size of the cantilever is 0.5mm*0.2mm-1.5mm*0.5mm.

9. A method for preparing a transmission electron microscope high-resolution in-situ temperature difference pressurization chip, characterized in that: The following steps are involved: S1. Prepare a Si(100) wafer A having a silicon nitride or silicon oxide insulating layer on both the front and back sides, the thickness of the insulating layer being 5-200 nm; S2. Transferring the patterns of the heating electrode, the voltage electrode, the heating wire, the voltage circuit, the heating line connecting the heating wire and the heating electrode, and the voltage line connecting the voltage circuit and the voltage electrode from the photolithography mask to the front side of the wafer A through a photolithography process, then developing the pattern in a positive photoresist developer, and then cleaning the surface with deionized water to obtain a wafer A-1; S3. The exposed silicon nitride or silicon oxide insulating layer on the front side of the wafer A-1 is etched away by a reactive ion etching process, and then the wafer is immersed in acetone with the front side facing up, and finally rinsed with acetone to remove the photoresist to obtain a wafer A-2; S4. Using electron beam evaporation coating process, a layer of metal film is evaporated on the front side of wafer A-2 to form heating electrodes, pressure electrodes, heating wires, pressure circuits, heating lines and pressure lines, and then the wafer is placed in acetone with the front side facing up for immersion and peeling, and finally rinsed with deionized water to remove the photoresist, leaving the metal layer, and obtaining wafer A-3; S5. Using a PECVD process, a layer of silicon nitride, silicon oxide or aluminum oxide is grown on the front side of the wafer A-3 as a protective layer to obtain a wafer A-4; S6. Using a photolithography process, the area to be etched is transferred from the photolithography mask to the back of the wafer A-4, then developed in a positive photoresist developer, and then the surface is cleaned with deionized water to obtain a wafer A-5; S7. Using a reactive ion etching process, the silicon nitride or silicon oxide on the back of the wafer A-5 to be etched is etched away, and then the back of the wafer is placed in acetone and immersed, and finally rinsed with acetone to remove the photoresist to obtain a wafer A-6; S8. Place the back side of wafer A-6 facing upward into a potassium hydroxide solution for wet etching until the exposed substrate silicon is completely etched, remove the wafer, rinse it with a large amount of deionized water, and blow dry it to obtain wafer A-7; S9. The exposed silicon nitride, silicon oxide or aluminum oxide protective layer on the front side of the wafer A-7 is etched away by a reactive ion etching process, and then the wafer is immersed in acetone with the front side facing up, and finally rinsed with acetone to remove the photoresist, thereby obtaining a wafer A-8; S10. Laser-slice wafer A-8 into independent chips.

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