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

Abstract

The present invention relates to a transmission electron microscope high-resolution in-situ suspended temperature difference pressurization chip and a preparation method thereof, wherein the chip comprises a substrate covered with an insulating layer on both sides, a central window is provided in the middle of the substrate, the central window is suspended, and a supporting layer is also covered on the central window; the supporting layer in the central window has two heating wires symmetrically arranged in the left and right directions and two pressurization circuits symmetrically arranged in the upper and lower directions, and the two pressurization circuits are located in the gap between the two heating wires; each heating wire is connected to four heating electrodes, and each heating electrode is connected to different positions of the heating wire through a heating circuit; each pressurization circuit is connected to a pressurization electrode, and each pressurization electrode is connected to the corresponding pressurization circuit through a pressurization circuit, and the chip can realize temperature difference and pressurization functions at the same time.

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 suspended 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] The current temperature difference chip still has defects such as low heating and cooling rate, insufficient temperature measurement and control accuracy, low resolution, high sample drift rate, inability to simultaneously achieve temperature difference and pressurization functions, and inconvenient sample placement. Therefore, it is necessary to improve the existing temperature difference chip. Summary of the invention

[0004] The present invention aims to provide a transmission electron microscope high-resolution in-situ suspended temperature difference pressurization chip capable of realizing temperature difference and pressurization functions simultaneously.

[0005] The specific plan is as follows:

[0006] A high-resolution in-situ suspended temperature difference pressurization chip for transmission electron microscope comprises a substrate covered with an insulating layer on both sides, a central window is provided in the middle of the substrate, the central window is suspended and covered with a supporting layer made of a transparent film; the supporting layer in the central window has two heating wires symmetrically arranged in the left and right and two pressurization circuits symmetrically arranged in the top and bottom, and the two pressurization circuits are located in the gap between the two heating wires; each heating wire is connected to four heating electrodes, and each heating electrode is connected to different positions of the heating wire through a heating circuit; each pressurization circuit is connected to a pressurization electrode, and each pressurization electrode is connected to the corresponding pressurization circuit through a pressurization circuit.

[0007] Preferably, a plurality of heat-insulating holes are provided in the gap between the two heating wires.

[0008] Preferably, a notch extending in the up-down direction is provided in the middle of each pressure electrode, and the above-mentioned heat insulation holes are evenly distributed in the notch of the two pressure electrodes in the up-down direction.

[0009] Preferably, the heat insulation hole is a square hole.

[0010] Preferably, the four heating electrodes of each heating electrode constitute two sets of equivalent circuits, which are respectively controlled by separate current source meters and voltage source meters. One set of loops in the two sets of equivalent circuits is responsible for supplying power for heating, and the other set of loops is responsible for real-time monitoring of the resistance value of the heating wire after heating.

[0011] Preferably, each voltage-applying circuit is respectively provided with a set of equivalent circuits to realize the voltage difference.

[0012] Preferably, the substrate is a silicon substrate, the insulating layer is a silicon nitride or silicon oxide insulating layer, the thickness of the silicon nitride or silicon oxide insulating layer is 0.5-5 um, and the thickness of the substrate is 50-500 um.

[0013] Preferably, the transmission electron microscope high-resolution in-situ suspended temperature difference pressurization chip has a chip size of 2mm*2mm-10mm*10mm or 4mm*8mm.

[0014] The present invention also provides a method for preparing a transmission electron microscope high-resolution in-situ suspended temperature difference pressurization chip, comprising the following steps:

[0015] S1. Prepare a Si (100) wafer A with a silicon nitride or silicon oxide layer on both sides, the thickness of the silicon nitride or silicon oxide layer is 5-200nm, and the thickness of the silicon wafer is 50-500um;

[0016] S2. Using a photolithography process, the center window pattern is transferred from the photolithography mask to any side of the wafer A, which is used as the back side, and then developed in a positive photoresist developer to obtain a wafer A-1;

[0017] S3. Using a reactive ion etching process, the silicon nitride or silicon oxide layer at the center window is etched off on the silicon nitride layer on the back of the wafer A-1, and then the wafer is immersed in acetone with the back side facing up, and finally rinsed with acetone to remove the photoresist to obtain a wafer A-2;

[0018] S4. Place the back side of wafer A-2 facing upward into a potassium hydroxide solution for wet etching until the thin film window appears, take out wafer A-2, rinse with a large amount of deionized water, and blow dry to obtain wafer A-3;

[0019] S5. Using a photolithography process, the patterns of the heating wire, the pressurizing circuit, the heating electrode, the pressurizing electrode, the heating line and the pressurizing line are transferred from the photolithography mask to the front side of the wafer A-3, and then developed in a positive photoresist developer, and then rinsed and cleaned the surface with deionized water to obtain a wafer A-4;

[0020] S6. Using electron beam evaporation, a layer of conductive material is deposited on the front side of wafer A-4, and then the front side of wafer A-4 is placed in acetone for immersion and peeling, and finally rinsed with deionized water to remove the photoresist, leaving a conductive layer corresponding to the pattern in step S5, to obtain wafer A-5;

[0021] S7. Using an ultraviolet laser direct writing lithography process, the small hole pattern of the central window is transferred from the photolithography mask to the front side of the wafer A-5, and then developed in a positive photoresist developer, and then rinsed and cleaned the surface with deionized water to obtain a wafer A-6;

[0022] S8. Using a reactive ion etching process, the silicon nitride or silicon oxide is etched at the small hole on the back of the wafer A-6, and then the front side of the wafer A-6 is immersed in acetone, and finally rinsed with acetone to remove the photoresist to obtain a wafer A-7;

[0023] S9. Laser-slice wafer A-7 into independent chips.

[0024] The transmission electron microscope high-resolution in-situ suspended temperature difference pressurization chip provided by the present invention has the following advantages compared with the prior art: the transmission electron microscope high-resolution in-situ suspended temperature difference pressurization chip provided by the present invention can implement different temperatures at both ends of the carried sample, and can also apply different voltages to the sample, and can study solid materials under two external field stimuli of different temperatures and voltages; and has the advantages of rapid temperature rise and fall, high resolution, precise temperature measurement and control, simultaneous realization of temperature difference and pressurization functions, convenient sample placement, and low sample drift rate. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 A top view of a high-resolution in-situ suspended temperature differential pressurization chip captured by a transmission electron microscope is shown.

[0026] Figure 2 An enlarged view of the central window of the high-resolution in-situ suspended temperature differential pressurization chip under transmission electron microscopy is shown.

[0027] Figure 3 A front view of a high-resolution in-situ suspended temperature differential pressurization chip captured by a transmission electron microscope is shown. DETAILED DESCRIPTION

[0028] 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.

[0029] The present invention will now be further described with reference to the accompanying drawings and specific implementation methods.

[0030] Example 1

[0031] like Figure 1-Figure 3 As shown, this embodiment provides a transmission electron microscope high-resolution in-situ suspended temperature difference pressurization chip, including a substrate 1, and the front and back sides of the substrate 1 are covered with an insulating layer 10. Among them, the substrate in this embodiment is a silicon substrate, and the insulating layer is a silicon nitride or silicon oxide insulating layer.

[0032] The substrate 1 has a central window 11 in the middle. The central window 11 is suspended in the air and is covered with a support layer 10 ′. The support layer 10 ′ is a silicon nitride layer or a silicon oxide layer.

[0033] The support layer in the central window 11 has two heating wires 12 symmetrically arranged on the left and right and two pressurizing circuits 13 symmetrically arranged on the top and bottom, and the two pressurizing circuits 13 are located in the gap between the two heating wires 12 .

[0034] The heating wire 12 is a spiral ring-shaped arc heating wire, with gaps between the arc heating wires, and they are not connected to each other; each heating wire 12 is connected to four heating electrodes 121, which are distributed on the same side edge of the substrate 1, and the eight heating electrodes 121 of the two heating wires 12 are respectively arranged on the left and right side edges of the substrate 1. Each heating electrode 121 is connected to a different position of the heating wire 12 through a heating line 122, and the four heating electrodes make the heating wire form two sets of equivalent circuits, and the two sets of equivalent circuits are controlled by separate current source meters and voltage source meters respectively; one of the two sets of equivalent circuits is responsible for power supply and heating, and the other set of circuits is responsible for real-time monitoring of the resistance value of the heating wire after heating.

[0035] Each voltage circuit 13 is connected to a voltage electrode 131, and the two voltage electrodes 131 of the two voltage circuits 13 are respectively arranged at the upper and lower edges of the substrate. Each voltage electrode 131 is connected to the corresponding voltage circuit 13 through a voltage line. Preferably, the two voltage circuits are respectively provided with a set of equivalent circuits to achieve a voltage difference.

[0036] In this embodiment, a plurality of heat-insulating holes 14 are further provided in the gap between the two heating wires 12 to reduce the mutual influence between the temperatures of the two heating wires 12 and improve the accuracy of temperature measurement and control.

[0037] Preferably, a notch extending in the up-down direction is provided in the middle of each pressurizing circuit 13 , and the above-mentioned heat insulation holes 14 are evenly distributed in the notches of the two pressurizing circuits 13 in the up-down direction.

[0038] More preferably, the thermal insulation hole 14 is square.

[0039] In this embodiment, the chip size of the transmission electron microscope high-resolution in-situ suspended temperature difference pressurization chip is 2mm*2mm-10mm*10mm; preferably, the chip size is 4mm*8mm.

[0040] In this embodiment, the thickness of the silicon nitride or silicon oxide insulating layer is 0.5-5 um, and the thickness of the substrate is 50-500 um.

[0041] In this embodiment, the central window is a square central window. Preferably, the size of the square central window is 0.5mm*0.5mm-1mm*1mm; more preferably, the size of the square central window is 0.8mm*0.8mm.

[0042] In this embodiment, the outer diameter of the arc heating wire of the heating layer is 0.15-0.5 mm, and the thickness is 50-500 nm. Preferably, the heating wire is made of metal gold, platinum, palladium, rhodium, molybdenum, tungsten, platinum-rhodium alloy or non-metallic molybdenum carbide.

[0043] In this embodiment, the size of the pressurized circuit is 2um*150um-5um*300um, and the thickness is 50-500nm. Preferably, the pressurized circuit is made of metal gold, platinum, palladium, rhodium, molybdenum, tungsten, platinum-rhodium alloy or non-metallic molybdenum carbide.

[0044] Example 2

[0045] This embodiment provides a method for preparing a transmission electron microscope high-resolution in-situ suspended temperature difference pressurization chip, comprising the following steps:

[0046] S1. Prepare a Si(100) wafer A with a silicon nitride or silicon oxide layer on both sides, the thickness of the silicon nitride or silicon oxide layer is 0.5-5um, and the thickness of the silicon wafer is 50-500um;

[0047] S2. Using a photolithography process, the center window pattern is transferred from the photolithography mask to any side of the wafer A, which is used as the back side, and then developed in a positive photoresist developer to obtain a wafer A-1;

[0048] 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;

[0049] More preferably, the exposure time is 20 s;

[0050] S3. Using a reactive ion etching process, the silicon nitride or silicon oxide layer at the center window is etched off on the silicon nitride layer on the back of the wafer A-1, and then the wafer is immersed in acetone with the back side facing up, and finally rinsed with acetone to remove the photoresist to obtain a wafer A-2;

[0051] S4. Place the back side of wafer A-2 facing upward into a potassium hydroxide solution for wet etching until only the film window is left on the front side, take out wafer A-2, rinse with a large amount of deionized water, and blow dry to obtain wafer A-3;

[0052] 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;

[0053] More preferably, the etching temperature is 80° C. and the etching time is 2 h;

[0054] S5. Using a photolithography process, the patterns of the heating wire, the pressurizing circuit, the heating electrode, the pressurizing electrode, the heating line and the pressurizing line are transferred from the photolithography mask to the front side of the wafer A-3, and then developed in a positive photoresist developer, and then rinsed and cleaned the surface with deionized water to obtain a wafer A-4;

[0055] Preferably, the photolithography process is exposure in the hard contact mode of the ultraviolet lithography machine, the photoresist used in the photolithography process is AZ5214E; the development time is 50s;

[0056] More preferably, the exposure time is 15 s;

[0057] Preferably, the heating wire is an arc-shaped heating wire with an outer diameter of 0.15-0.5 mm and a thickness of 50-500 nm;

[0058] S6. Using electron beam evaporation, a metal film is deposited on the front side of wafer A-4, and then the front side of wafer A-4 is placed in acetone for immersion and peeling, and finally rinsed with deionized water to remove the photoresist, leaving a conductive layer corresponding to the pattern in step S5, to obtain wafer A-5;

[0059] Preferably, the material of the conductive layer is metal gold, platinum, palladium, rhodium, molybdenum, tungsten, platinum-rhodium alloy or non-metallic molybdenum carbide; the thickness of the conductive layer is 50-500nm;

[0060] S7. Using an ultraviolet laser direct writing lithography process, a small hole pattern of a central window is constructed on the front side of the wafer A-5, and then developed in a positive photoresist developer, and then rinsed and cleaned the surface with deionized water to obtain a wafer A-6;

[0061] Preferably, the photoresist used in the UV laser direct writing process is AZ5214E; the output power is 260W / us;

[0062] S8. Using a reactive ion etching process, the silicon nitride or silicon oxide is etched at the small hole on the back of the wafer A-6, and then the front side of the wafer A-6 is immersed in acetone, and finally rinsed with acetone to remove the photoresist to obtain a wafer A-7;

[0063] Preferably, the size of the small hole is 3um*30um-5um*50um;

[0064] S9. Laser-slice wafer A-7 into independent chips.

[0065] 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 suspended temperature difference pressurization chip for transmission electron microscopy, characterized in that: It comprises a substrate covered with insulating layers on both sides, a central window is provided in the middle of the substrate, the central window is suspended and covered with a supporting layer made of a transparent film; the supporting layer in the central window has two heating wires symmetrically arranged in the left and right and two pressurizing circuits symmetrically arranged in the upper and lower parts, and the two pressurizing circuits are located in the gap between the two heating wires; each heating wire is connected to four heating electrodes, and each heating electrode is connected to different positions of the heating wire through a heating circuit; each pressurizing circuit is connected to a pressurizing electrode, and each pressurizing electrode is connected to the corresponding pressurizing circuit through a pressurizing circuit; a plurality of heat-insulating holes are also provided in the gap between the two heating wires; each pressurizing circuit is respectively provided with a group of equivalent circuits to realize a voltage difference.

2. The transmission electron microscope high-resolution in-situ suspended temperature difference pressurization chip according to claim 1, characterized in that: A notch extending in the up-down direction is provided in the middle of each pressurizing circuit, and the heat-insulating holes are evenly distributed in the notches of the two pressurizing circuits in the up-down direction.

3. The transmission electron microscope high-resolution in-situ suspended temperature difference pressurization chip according to claim 1, characterized in that: The heat insulation hole is a square hole.

4. The transmission electron microscope high-resolution in-situ suspended temperature difference pressurization chip according to claim 1, characterized in that: The four heating electrodes of each heating electrode constitute two sets of equivalent circuits, which are respectively controlled by separate current source meters and voltage source meters. One set of loops in the two sets of equivalent circuits is responsible for supplying power for heating, and the other set of loops is responsible for real-time monitoring of the resistance value of the heating wire after heating.

5. The transmission electron microscope high-resolution in-situ suspended temperature difference pressurization chip according to claim 1, characterized in that: The substrate is a silicon substrate, the insulating layer is a silicon nitride or silicon oxide insulating layer, the thickness of the silicon nitride or silicon oxide insulating layer is 0.5-5um, and the thickness of the substrate is 50-500um.

6. The transmission electron microscope high-resolution in-situ suspended temperature difference pressurization chip according to claim 1, characterized in that: The transmission electron microscope high-resolution in-situ suspended temperature difference pressurization chip has a chip size of 2mm*2mm-10mm*10mm or 4mm*8mm.

7. A method for preparing a transmission electron microscope high-resolution in-situ suspended temperature difference pressurization chip as claimed in claim 1, characterized in that: The following steps are involved: S1. Prepare a Si(100) wafer A with a silicon nitride or silicon oxide layer on both sides, the thickness of the silicon nitride or silicon oxide layer is 0.5-5um, and the thickness of the silicon wafer is 50-500um; S2. Using a photolithography process, the center window pattern is transferred from the photolithography mask to any side of the wafer A, which is used as the back side, and then developed in a positive photoresist developer to obtain a wafer A-1; S3. Using a reactive ion etching process, the silicon nitride or silicon oxide layer at the center window is etched off on the silicon nitride layer on the back of the wafer A-1, and then the wafer is immersed in acetone with the back side facing up, and finally rinsed with acetone to remove the photoresist to obtain a wafer A-2; S4. Place the back side of wafer A-2 facing upward into a potassium hydroxide solution for wet etching until only the film window is left on the front side, take out wafer A-2, rinse with a large amount of deionized water, and blow dry to obtain wafer A-3; S5. Using a photolithography process, the patterns of the heating wire, the pressurizing circuit, the heating electrode, the pressurizing electrode, the heating line and the pressurizing line are transferred from the photolithography mask to the front side of the wafer A-3, and then developed in a positive photoresist developer, and then rinsed and cleaned the surface with deionized water to obtain a wafer A-4; S6. Using electron beam evaporation, a metal film is deposited on the front side of wafer A-4, and then the front side of wafer A-4 is placed in acetone for immersion and peeling, and finally rinsed with deionized water to remove the photoresist, leaving a conductive layer corresponding to the pattern in step S5, to obtain wafer A-5; S7. Using an ultraviolet laser direct writing lithography process, a small hole pattern of a central window is constructed on the front side of the wafer A-5, and then developed in a positive photoresist developer, and then rinsed and cleaned the surface with deionized water to obtain a wafer A-6; S8. Using a reactive ion etching process, the silicon nitride or silicon oxide is etched at the small hole on the back of the wafer A-6, and then the front side of the wafer A-6 is immersed in acetone, and finally rinsed with acetone to remove the photoresist to obtain a wafer A-7; S9. Laser-slice wafer A-7 into independent chips.

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