An emission tip, thermal field emission electron source and manufacturing method

Abstract

The present invention provides an emission tip, a thermal field emission electron source and a manufacturing method, which belong to the field of electron beam imaging detection. The emission tip provided by the present invention includes a main body and an extension portion; one end of the extension portion is axially connected to the main body, and the other end extends axially in a direction away from the main body, and there is a first connection portion that gradually shrinks; any axial cross section of the extension portion is a pair of at least one pair of concave arc structures arranged opposite to each other, and the side wall of the extension portion is surrounded by at least one circle of groove portions. The present invention also provides a thermal field emission electron source including the emission tip and a manufacturing method. The emission tip and thermal field emission electron source provided by the present invention, the groove portion and the concave arc structure cooperate with each other, further optimize the distribution of the high voltage electric field at the tip, improve the physical and chemical properties of the contour surface, and obtain higher brightness, smaller total emission current and higher stability.

Description

Technical Field

[0001] The present invention relates to the field of electron beam imaging detection, and in particular to an emission tip, a thermal field emission electron source and a manufacturing method thereof. Background Art

[0002] Thermal field emission electron sources are mainly used in high-end thermal field electron microscopes, semiconductor testing and measurement equipment, and are the core components of electron beam imaging systems. The main functional advantages of thermal field emission electron sources are: long life, continuous operation for more than 1 year, stable power, small fluctuation, high brightness, and wide application. The optical performance of thermal field emission electron sources has an important impact on the imaging system and work efficiency of the entire equipment.

[0003] Figure 1 It is a common thermal field emission electron source currently on the market (B is the focusing system, C is the vacuum system, and D is the imaging system). Figure 2 and Figure 3 yes Figure 1 A partial enlarged view of Figure 3 It can be seen that the side profile of the tip A of a common thermal field emission electron source is a straight or nearly straight cone. The electron source under this structure is about E7A / cm 2 / sr, unable to work at higher brightness; the total emission current is relatively large, depending on the application scenario, the total emission current is generally 80-400μA, the emission stability is poor, if the emission brightness is forcibly increased, the emission stability will decrease, the total emission current will increase, and the working life will be shortened.

[0004] In view of this, the present invention is proposed. Summary of the invention

[0005] The present invention provides an emission tip, a thermal field emission electron source and a manufacturing method, which can effectively solve the problems in the prior art that ordinary thermal field emission electron sources cannot work stably for a long time at higher brightness and have a large total emission current.

[0006] To solve the above problems, the present invention adopts the following solutions:

[0007] In a first aspect, the present invention provides a firing tip, comprising a body portion and an extension portion;

[0008] One end of the extension portion is axially connected to the main body portion, and the other end thereof extends axially in a direction away from the main body portion, and has a gradually shrinking first connection portion;

[0009] Any axial cross section of the extension portion is a pair of oppositely arranged inwardly concave arc-shaped structures, and the side wall of the extension portion is surrounded by at least one circle of groove portions.

[0010] The extension portion in the present embodiment extends axially in a direction away from the main body portion, and has a gradually shrinking first connection portion, the first connection portion is located at one end of the extension portion away from the main body portion, and any axial cross-section of the extension portion is a pair of at least one section of concave arc structures arranged opposite to each other. This structural design can make the electric field bend more strongly at the tip, thereby making the equipotential lines of the electric field at the tip denser and the electric field intensity higher. In addition, at least one circle of groove portions is provided around the side wall of the extension portion, and the groove portions and the pair of concave arc structures cooperate with each other to further optimize the distribution of the high-voltage electric field at the tip, improve the physical and chemical properties of the contour surface, and improve the stability of the migration of the zirconium mixture on the surface. Experiments have shown that this results in higher brightness, smaller total emission current and higher stability.

[0011] In other preferred solutions, the extension portion includes a first connecting portion and a second connecting portion integrally formed axially; the second connecting portion is integrally formed with the main body, and the groove portion is arranged on the second connecting portion. The groove portion is arranged near the bottom of the extension portion, which is convenient for etching and can ensure that the remaining portion of the extension portion can still maintain sufficient width and strength after the groove portion is etched.

[0012] In other preferred schemes, an emitting end is axially extended from one end of the first connecting portion away from the main body portion, and the emitting end is a cylindrical structure, and one end of the cylinder is integrally formed with the extension portion, and the radius of the emitting end remains stable, thereby increasing the electric field strength on the tip surface when the radius of the emitting end remains unchanged and the external suction voltage remains unchanged, while reducing the electric field strength on the side of the tip and reducing the total emission current.

[0013] In other preferred schemes, an emitting end is axially extended from one end of the first connecting part away from the main body; the emitting end is a cone structure, and the bottom of the cone is integrally formed with the first connecting part, and is also mainly used to increase the electric field strength on the tip surface and reduce the total emission current.

[0014] In other preferred solutions, a launch end is axially extended from one end of the first connection portion away from the main body portion; the launch end is a platform structure, and the smaller bottom of the platform is integrally formed with the first connection portion.

[0015] In other preferred solutions, on any axial cross section, with the midpoint of the tip of the first connecting portion as the coordinate origin, in the first quadrant:

[0016] The trajectory curve of the first connecting part is: y1 = 0.1191x 2 -0.1037x+0.7841;

[0017] The trajectory curve of the groove portion is: y2 = 0.1976x 2-0.485x+20.926;

[0018] Among them, x is the distance from the coordinate origin of a point on the first connecting part or the groove part in the direction along the central axis of the main body part; y1 is the shortest distance from a point on the first connecting part to the central axis; y2 is the shortest distance from a point on the groove part to the central axis; the units of x, y1 and y2 are all μm.

[0019] In other preferred solutions, on any axial cross section, with the midpoint of the tip of the first connecting portion as the coordinate origin, in the first quadrant:

[0020] The trajectory curve of the first connecting part is: y1 = 0.1617x 2 -0.2528x+0.7471;

[0021] The trajectory curve of the groove portion is: y2 = 0.1402x 2 +0.2643x+25.639;

[0022] Among them, x is the distance from the coordinate origin of a point on the first connecting part or the groove part in the direction along the central axis of the main body part; y1 is the shortest distance from a point on the first connecting part to the central axis; y2 is the shortest distance from a point on the groove part to the central axis; the units of x, y1 and y2 are all μm.

[0023] In other preferred solutions, on any axial cross section, with the midpoint of the tip of the first connecting portion as the coordinate origin, in the first quadrant:

[0024] The trajectory curve of the first connecting part is: y=0.0872x 2 -0.2271x+2.7521;

[0025] Wherein, x is the distance from a point on the first connecting portion to the coordinate origin in the direction along the central axis of the main body; y is the shortest distance from a point on the first connecting portion to the central axis; the units of x and y are both μm.

[0026] In other preferred solutions, a transmitting end is axially extended from one end of the first connecting portion away from the main body portion;

[0027] On any axial cross section, with the midpoint of the tip of the first connecting part as the coordinate origin, in the first quadrant:

[0028] The trajectory curve of the first connecting part is: y1 = 0.077x 2 -0.0048x+1.8974;

[0029] The trajectory curve of the groove portion is: y2 = 2.5193x 2-12.739x+59.261;

[0030] Among them, x is the distance from the coordinate origin of a point on the first connecting part or the groove part in the direction along the central axis of the main body part; y1 is the shortest distance from a point on the first connecting part to the central axis; y2 is the shortest distance from a point on the groove part to the central axis; the units of x, y1 and y2 are all μm.

[0031] In a second aspect, the present invention provides a thermal field emission electron source comprising the emission tip, the thermal field emission electron source further comprising a zirconium mixture and a heating fork;

[0032] The zirconium mixture is sleeved on the outer wall of the main body, and the distance between the zirconium mixture and the extension part is less than or equal to 3 mm;

[0033] The heating fork is axially connected to one end of the main body, and the other end of the main body is axially connected to the extension portion.

[0034] The heating fork can generate heat after being energized, thereby heating the extension part, and the extension part can emit electrons under the action of the electric field. The zirconization mixture of this scheme is mainly zirconium compound and contains a certain proportion of other element additives. The zirconization mixture can migrate and diffuse to the surface of the extension part after heating to reduce the electron escape work function at the emission end. The distance between the zirconization mixture and the extension part is less than or equal to 3 mm, and the distance is short, which facilitates the diffusion of the zirconization mixture to the surface of the extension part.

[0035] In other preferred embodiments, the zirconium compound comprises at least zirconium compound, and Th, Si, Ti and Ca elements sequentially distributed from the inside to the outside; wherein the content of Th, Si, Ti and Ca elements is 0.001%-1% of the total mass of the zirconium compound. This configuration of the zirconium compound facilitates the zirconium compound to be smoothly diffused to the surface of the extension portion.

[0036] The present invention provides a method for manufacturing a thermal field emission electron source in a third aspect, which comprises the following steps:

[0037] a. inserting the emission tip into the reaction solution, wherein the reaction solution is provided with an electrode ring;

[0038] b. connecting the emission tip and the electrode ring to form an energized circuit so that the emission tip undergoes electrochemical corrosion in the reaction solution;

[0039] c. Monitor the current parameters of the circuit in step b, and control the on and off of the circuit according to the current parameters to form the thermal field emission electron source.

[0040] The concave arc profile in this solution can be obtained through a physical, chemical or electrochemical corrosion process under precise control. By utilizing the particularity of the tooling, the corrosion / etching speed of the groove portion is faster, and no manual operation is required, resulting in higher etching accuracy.

[0041] In other preferred schemes, step a is specifically as follows: inserting the emission tip 0.1-3 mm below the liquid surface of the reaction solution; wherein the temperature of the reaction solution is 5-40° C., and the extension part reacts more fully with the reaction solution, facilitating etching.

[0042] In other preferred solutions, the step c is specifically: monitoring the current parameters of the energized circuit in step b, and transmitting the current parameters to the controller; when the current is lower than 1-20 mA, the controller automatically cuts off the circuit to form the thermal field emission electron source. The circuit current is monitored in real time, and the controller is used to automatically control the on and off of the circuit without manual operation.

[0043] Compared with the prior art, the present invention has the following beneficial effects:

[0044] The present application provides an emitting tip, in which an extension portion forms an inwardly concave arc-shaped profile. This structural design can cause the electric field to bend more strongly at the tip, thereby making the equipotential lines of the tip electric field denser and the electric field strength higher. In addition, at least one circle of groove portions is provided around the side wall of the extension portion. The groove portions cause the cylinder to become thinner in sections during the thinning process, slowing down the thinning speed and producing a buffering effect. The groove portions and the inwardly concave arc-shaped structure cooperate with each other to further optimize the distribution of the high-voltage electric field at the tip, improve the physical and chemical properties of the profile surface, and experiments have shown that higher brightness, smaller total emission current and higher stability are thereby achieved.

[0045] The present application also provides a thermal field emission electron source including the emission tip and a method for manufacturing the same. The thermal field emission electron source can be obtained through a physical, chemical or electrochemical corrosion process under precise control. By utilizing the particularity of the tooling, the corrosion / etching speed of the groove portion is faster, and no manual operation is required, resulting in higher etching accuracy. BRIEF DESCRIPTION OF THE DRAWINGS

[0046] In order to more clearly illustrate the specific implementation methods of the present invention or the technical solutions in the prior art, the drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some implementation methods of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0047] Figure 1 A schematic diagram of the location of an existing common thermal field emission electron source in the background technology of this application;

[0048] Figure 2 It is a schematic diagram of the structure of the emission tip in the background technology of this application;

[0049] Figure 3 for Figure 2 A partial enlarged view of the middle launch tip;

[0050] Figure 4a One of the structural schematic diagrams of a specific emission tip described in this application;

[0051] Figure 4b It is a schematic diagram of the structures of three different transmitting ends described in this application;

[0052] Figure 5 This is a second structural schematic diagram of a specific emission tip described in this application;

[0053] Figure 6 This is a third structural schematic diagram of a specific emission tip described in this application;

[0054] Figure 7 This is a schematic structural diagram of a specific thermal field emission electron source described in this application;

[0055] Figure 8 A schematic diagram of a specific method for manufacturing a thermal field emission electron source described in this application;

[0056] Fig. 9 One of the electron source emission test models established using simulation software in this application;

[0057] Fig.10 This is the second electron source emission test model established using simulation software in this application;

[0058] Fig.11 An emission brightness curve diagram of a specific thermal field emission electron source described in this application;

[0059] Fig.12 This is a schematic diagram of the structure of the emission tip style 1 described in this application;

[0060] Fig.13 A schematic diagram of the cross-sectional trajectory of the emission tip style 1 described in the present application;

[0061] Fig.14 This is a schematic diagram of the structure of the second emission tip style described in this application;

[0062] Fig.15 A schematic diagram of the cross-sectional trajectory of the second emission tip style described in the present application;

[0063] Fig.16 A schematic diagram of the cross-sectional trajectory of the emission tip style three described in the present application;

[0064] Fig.17 This is a schematic diagram of the structure of the emission tip style 4 described in this application;

[0065] Fig.18 A schematic diagram of the cross-sectional trajectory of the emission tip style 4 described in the present application;

[0066] Fig.19a , 19b 19c is a schematic diagram of emission current data of a thermal field emission electron source with a specific structure of the present application;

[0067] Fig.20a , 20b and 20c are schematic diagrams of emission current data of a conventional structure thermal field emission electron source;

[0068] Fig.21 This is a schematic diagram of the structure of a specific zirconium mixture of the present application.

[0069] In the above drawings, the components represented by the reference numerals are listed as follows:

[0070] Main body portion 100; zirconium compound 101; extension portion 200; groove portion 201; first connection portion 202; heating fork 300; terminal post 400; ceramic seat 500. DETAILED DESCRIPTION

[0071] In order to make the above and other features and advantages of the present invention more clear, the present invention is further described below in conjunction with the accompanying drawings. It should be understood that the specific embodiments given herein are for the purpose of explaining to those skilled in the art and are only exemplary and not restrictive.

[0072] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as limiting the present invention.

[0073] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In the description of the present invention, the meaning of "plurality" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0074] In the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements, unless otherwise clearly defined. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0075] In the present invention, unless otherwise clearly specified and limited, a first feature being "above" or "below" a second feature may mean that the first and second features are in direct contact, or the first and second features are in indirect contact through an intermediate medium. Moreover, a first feature being "above", "above" or "above" a second feature may mean that the first feature is directly above or obliquely above the second feature, or simply means that the first feature is higher in level than the second feature. A first feature being "below", "below" or "below" a second feature may mean that the first feature is directly below or obliquely below the second feature, or simply means that the first feature is lower in level than the second feature.

[0076] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine the different embodiments or examples described in this specification and the features of the different embodiments or examples, without contradiction.

[0077] Please refer to Figure 4aIn a first aspect, the present invention provides a launching tip, which includes a main body 100 and an extension portion 200; one end of the extension portion 200 is axially connected to the main body 100, and the other end extends axially in a direction away from the main body 100, and there is a gradually shrinking first connecting portion 202; any axial cross section of the extension portion 200 is a pair of oppositely arranged at least one section of concave arc structure, and the side wall of the extension portion 200 is ringed with at least one circle of groove portion 201.

[0078] The extension portion 200 and the main body portion 100 are integrally formed and are both made of single crystal tungsten.

[0079] The extension portion 200 in the present embodiment extends axially in a direction away from the main body portion 100, and has a gradually shrinking first connecting portion 202, and any axial cross-section of the extension portion 200 is a pair of at least one section of relatively arranged inwardly concave arc structures, where the pair of inwardly concave arc structures gradually approach each other from their bottom ends to their top ends. This structural design can make the electric field bend more strongly at the tip, the equipotential lines of the electric field at the tip are denser, and the formed electric field intensity is higher. In addition, at least one circle of groove portions 201 is provided on the side wall of the extension portion 200, and the number, shape, width and depth of the groove portions 201 can be adjusted as needed. The groove portions 201 and the inwardly concave arc structures cooperate with each other to further optimize the distribution of the high-voltage electric field at the tip, improve the physical and chemical properties of the contour surface, and experiments have shown that higher brightness, smaller total emission current and higher stability are thereby achieved.

[0080] In other embodiments, the bottom of the extension portion 200 may also be a regular polygon. In this case, the trajectory equation of the concave arc structure will be adaptively adjusted, which will not be elaborated here.

[0081] Further, the extension part 200 includes a first connection part 202 and a second connection part which are integrally formed axially; the second connection part is integrally formed with the main body 100, and the groove part 201 is arranged on the second connection part, and an emission end is axially extended from one end of the first connection part 202 away from the main body 100. The groove part 201 is arranged near the bottom of the extension part 200, which is convenient for etching and can ensure that the remaining part of the extension part 200 can still maintain sufficient width and strength after the groove part 201 is etched.

[0082] The groove portion 201 in this embodiment is arranged near the bottom of the extension portion 200. Since the extension portion 200 gradually tapers from bottom to top, the cross-sectional area near the bottom is larger, which facilitates etching of the groove portion 201 to avoid the cross-sectional area of ​​the remaining portion after etching the groove portion 201 being too small.

[0083] It should be noted that a variety of etching methods can be used for the groove portion 201 in this embodiment, as long as the morphology of the etched groove portion 201 is consistent with the requirements of this solution. In other words, the etching method for the groove portion 201 in this embodiment is essentially to obtain a groove portion 201 that satisfies the morphology. Manual etching and electric etching are theoretically similar solutions.

[0084] This groove structure design enables the zirconium compound to have a more stable migration efficiency when diffusing on the surface. The groove 201 makes the cylinder thinner in sections, slowing down the thinning speed and creating a buffering effect, so as to facilitate a more stable migration rate of the zirconium compound 101 during its migration.

[0085] In other embodiments, etching methods are differentiated according to the difficulty of etching. In this case, manual etching and electric etching belong to different schemes, and can also be obtained through physical, chemical or electrochemical etching processes under precise control.

[0086] Furthermore, if Figure 4b As shown in the middle right figure, an emitting end is axially extended from one end of the first connecting portion 202 away from the main body portion 100; the emitting end is a cylindrical structure, and one end of the cylinder is connected to the first connecting portion 202, and the radius of the emitting end remains stable, thereby increasing the electric field strength on the tip surface while reducing the electric field strength on the side of the tip and reducing the total emission current when the radius of the emitting end remains unchanged and the external suction voltage remains unchanged.

[0087] It should be noted that if Figure 5 and Figure 6 The main body 100 in this embodiment and other embodiments may be a cylindrical or prism structure. One end of the main body 100 is integrally connected to the extension 200. A zirconium compound 101 is arranged around the main body 100. The zirconium compound 101 diffuses to the surface of the extension 200 when heated to reduce the electron work function at the emission end. The location of the zirconium compound 101 may be adjusted according to actual conditions.

[0088] Furthermore, if Figure 4b As shown in the middle left figure, an emitting end is axially extended from one end of the first connecting portion 202 away from the main body portion 100; the emitting end is a cone structure, and the bottom of the cone is connected to the first connecting portion 202, and is also mainly used to increase the electric field strength on the tip surface and reduce the total emission current.

[0089] Furthermore, if Figure 4b As shown in the middle figure, a transmitting end is axially extended from one end of the first connecting portion 202 away from the main body 100 ; the transmitting end is a platform structure, and the smaller bottom of the platform is connected to the first connecting portion 202 .

[0090] In the above two embodiments, a transmitting end is axially extended at one end of the extension part 200 away from the main body part 100. Fig.12 and attached Fig.14 The structure of the transmitting end is not drawn in the figure, and "axial extension" means that the main body 100, the extension part 200 and the transmitting end are coaxially arranged. The transmitting end can be a cylindrical structure, a conical structure or a table structure, all of which can increase the electric field strength on the tip surface, while reducing the electric field strength on the side of the tip, thereby reducing the total transmitting current.

[0091] In addition, in this embodiment and other embodiments, the length and thickness of the transmitting end are not limited, and the size of the transmitting end can be adjusted according to the size of the first connecting portion 202 and actual needs.

[0092] The subsequent four specific embodiments provide four different forms of the first connecting portion 202 and the groove portion 201 that can provide higher brightness values. For ease of presentation, in a two-dimensional orthogonal coordinate system, the midpoint of the tip of the first connecting portion 202 is taken as the coordinate origin, and the distance from the point on the first connecting portion 202 or the groove portion 201 along the central axis of the main body 100 to the coordinate origin is taken as x; the shortest distance from a point on the first connecting portion 202 to the central axis is taken as y1; the shortest distance from a point on the groove portion 201 to the central axis is taken as y2; the unit is μm; select as many point values ​​as possible from the following four embodiments respectively, and draw the trajectory curve of the first connecting portion 202 or the groove portion 201.

[0093] It should be noted that in the subsequent embodiments, only the portion of the trajectory curve of the first connection portion 202 and the groove portion 201 in the first quadrant is drawn, that is, only half of the cross-sectional view of the first connection portion 202 or the groove portion 201 is shown. In addition, the groove portion 201 in this solution is arranged on the second connection portion, and the shape, number and position of the groove portion 201 on the second connection portion are not limited to the types described in the embodiments of this specification, and the distinction between the first connection portion 202 and the second connection portion is mainly for the convenience of describing the position of the groove portion 201, and does not represent two different structures. Fig.12 , Fig.14 and Fig.17 In the embodiment, the groove portion 201 is the second connection portion.

[0094] In specific embodiment 1, the specific structure of style 1 is as follows Fig.12 As shown, the width of the groove portion 201 is greater than the length of the first connecting portion 202. In the first quadrant, the corresponding values ​​of x and y are shown in Table 1:

[0095] Table 1 Coordinates of points for side profile drawing

[0096]

[0097]

[0098] According to Table 1, Fig.13 The graph shown, where:

[0099] The trajectory curve Y1 of the first connection portion 202 is: y1 = 0.1191x 2 -0.1037x+0.7841; in the preferred solution, 2 <x<60;

[0100] The trajectory curve Y2 of the groove portion 201 is: y2 = 0.1976x 2 -0.485x+20.926; in the preferred embodiment, 60≤x<170.

[0101] It should be noted that the tip of the first connection portion 202 in the present application only refers to the sharpest point of the first connection portion 202, and the sharpest point may still be at a certain distance, so the middle of the tip is used as the origin in the present application.

[0102] In specific embodiment 2, the specific structure of style 2 is as follows Fig.14 As shown, the width of the groove portion 201 is approximately equal to the length of the first connecting portion 202. In the first quadrant, the corresponding values ​​of x and y are shown in Table 2:

[0103] Table 2 Coordinates of points for side profile drawing

[0104]

[0105]

[0106] According to Table 2, Fig.15 The graph shown, where:

[0107] The trajectory curve Y1 of the first connection portion 202 is: y1 = 0.1617x 2 -0.2528x+0.7471; in the preferred solution, 2 <x<90;

[0108] The trajectory curve Y2 of the groove portion 201 is: y2 = 0.1402x 2 +0.2643x+25.639; in the preferred embodiment, 90≤x<160.

[0109] In specific embodiment 3, in the first quadrant, the corresponding values ​​of x and y are shown in Table 3:

[0110] Table 3 Coordinates of points for side profile drawing

[0111]

[0112]

[0113] According to Table 3, Fig.16 The graph shown, where:

[0114] The trajectory curve Y of the first connection portion 202 is: y=0.0872x 2 -0.2271x+2.7521; in the preferred solution, 2 <x<170。

[0115] It should be noted that the two ends of the extension portion in the specific embodiment 3 directly extend and converge, and the extension portion in this embodiment can be regarded as a combination of the extension portion and the tip portion in other specific embodiments.

[0116] In specific embodiment 4, the specific structure of pattern 4 is as follows Fig.17 As shown, the length of the groove portion 201 is smaller than the length of the first connecting portion 202. In the first quadrant, the corresponding values ​​of x and y are shown in Table 4:

[0117] Table 4 Coordinates of points for side profile drawing

[0118]

[0119]

[0120] According to Table 4, Fig.18 The graph shown, where:

[0121] The trajectory curve Y1 of the first connection portion 202 is: y1 = 0.077x 2 -0.0048x+1.8974; in the preferred solution, 2 <x<155;

[0122] The trajectory curve Y2 of the groove portion 201 is: y2 = 2.5193x 2 -12.739x+59.261; in the preferred embodiment, 155≤x<175.

[0123] It should be noted that the emitting tips in the above-mentioned embodiments 1, 2 and 4 can all produce relatively high brightness, and the emitting tips in the corresponding experiments of this application are mainly based on embodiment 2.

[0124] like Figure 7 and Figure 8 As shown, the present invention provides a thermal field emission electron source including an emission tip in a second aspect, the thermal field emission electron source also includes a zirconium mixture 101 and a heating fork 300;

[0125] The zirconium-containing mixture 101 is sleeved on the outer wall of the main body 100, and the spacing between the main body 100 and the extension part 200 is less than or equal to 3 mm; the zirconium-containing mixture 101 is mainly composed of zirconium and a certain proportion of other element additives. The heating fork 300 is axially connected to one end of the main body 100, and the other end of the main body 100 is axially connected to the extension part 200.

[0126] The heating fork 300 can generate heat after being energized, and then transfer the heat to the extension part 200 to heat the extension part 200. The heating fork 300 is made of a material with good thermal conductivity, preferably a tungsten fork. The number of forks of the tungsten fork is the same as the number of the terminal 400. The extension part 200 can emit electrons under the action of the electric field. Since electrons need to do work to overcome the surface potential barrier when escaping from the metal surface, the zirconium mixture 101 can migrate and diffuse to the surface of the extension part 200 after heating, which can effectively reduce the electron escape work of the emission end. The spacing between the zirconium mixture 101 and the extension part 200 is less than or equal to 3 mm, and the distance is short, which is convenient for the zirconium mixture 101 to diffuse to the surface of the extension part 200, and makes the migration rate of the mixed zirconide more stable during the migration process.

[0127] Optional, such as Fig. 9 As shown, in this embodiment and other embodiments, the zirconium mixture 101 is preferably zirconium oxide containing other trace rare earth element additives, the terminal 400 is a metal wire, and a ceramic seat 500 is also provided on the outside of the metal wire.

[0128] like Fig.21 As shown in a specific embodiment, the zirconium mixture is composed of Zr-Th-Si-Ti-Ca. The contents of trace elements such as Th-Si-Ti-Ca are in the range of [0.001%-1%], and the distribution of these trace elements from the inside to the outside in the actual object is roughly as follows: Fig.21 , from the inside to the outside (or from the bottom to the top), they are Th, Si, Ti, and Ca. The addition of these trace elements in the zirconium mixture makes the migration rate of the mixed zirconium compound more stable during the migration process.

[0129] In another specific embodiment, the content of trace elements such as Th-Si-Ti-Ca is around 0.08%, and the addition of Th-Si-Ti-Ca plays a role in lubricating the diffusion path, ensuring that the zirconium compound is more stable and durable when diffusing and flowing on the surface of single crystal tungsten. The melting point of Ca oxide is about 2572°C, the melting point of titanium oxide is about 1840°C, and the melting point of silicon oxide is about 1702°C. Considering the melting point, the saturated vapor pressure of elements with high melting points is low, and the evaporation loss rate is slow, so they are placed in a relatively upper (outer) position, and the saturated vapor pressure of elements with low melting points is high, and the evaporation loss rate is fast, so they are placed in a relatively lower (inner) position, so that the evaporation loss rate of these three elements is uniform as a whole. The Th element has a certain additional contribution to reducing the work function of the emission end, so it is placed at the bottom (inner), closer to the surface of the single crystal tungsten, to ensure that the Th element diffuses more smoothly to the tip. Therefore, the order of added elements from top (outer) to bottom (inner) is Ca-Ti-Si-Th.

[0130] The comparison of the electron optical performance test results of the thermal field emission electron source provided by this solution and the traditional thermal field electron source is shown in Table 5:

[0131] Table 5 Comparison of the optical performance of the thermal field emission electron source of this scheme and the traditional thermal field electron source

[0132]

[0133]

[0134] In Table 5 above, 1.1μmdenka is a traditional electron source (an electron source produced by Denka Electric Co., Ltd. of Japan), and HBS 0.3μm is the technology of this solution. There are three groups of different imaging conditions for comparison test experiments. In each group of experiments, the parameters of the first five electron optical systems are the same, and the resolution obtained by the final test is smaller for the technology of this solution. Therefore, it can be seen from Table 5 that the thermal field emission electron source of this solution has better resolution than the traditional thermal field electron source test electron optical performance.

[0135] The specific design of the verification experiment is as follows. The test period is 3 months. The test parameters are as follows:

[0136] Vacuum 8E-10torr;

[0137] Test high voltage: HV: 12kv;

[0138] Test environment: clean room;

[0139] Test tools: extractor, suppressor, anode.

[0140] The experimental results are as follows Fig.19a , Fig.19b as well as Fig.19c As shown, Fig.20a , Fig.20b as well as Fig.20c The parameter change diagram corresponding to the traditional electron source. Among them, Ie is the total emission current, beam is the current of a part of the central beam measured by the electron optical system, and beam is the experimental measurement value. The obtained beam current varies due to the differences in different electron optical test systems. In order to compare the data obtained in different electron optical test systems, the beam value is uniformly converted into angular density (the current value measured under a unit solid angle) through a formula. At present, in most thermal field electron microscope systems on the market, the converted angular density values ​​can be effectively compared.

[0141] Fig.19a , Fig.19b as well as Fig.19c The electron source parameters provided in Example 2 of this scheme, wherein: Fig.19a The total emission current Ie is about 90μA, which is much smaller than Fig.20a 600μA of the traditional electron source, and Fig.19c The angular density in the Fig.20c Although the angular density of the traditional electron source is also approximately equal to 2mA / sr, the total emission current is too large at this time, reaching about 600μA, and it cannot be used in commercial products. The total emission current of the electron source on commercial products is generally required not to exceed 300μA. When it is 400μA, the imaging quality of the electron optical system will be partially reduced. When it exceeds 400μA, the imaging quality of the electron optical system will drop rapidly, the stability and life of the electron source will also drop, and at the same time, the vacuum of the electron gun will also drop and fluctuate, and high-voltage sparks are likely to occur.

[0142] When the total emission current is 300 μA, the angular density of the traditional electron source is only about 1 mA / sr, and when the total emission current is 90 μA, the angular density is only about 0.3 mA / sr. Under the condition that the total emission current is equal, the angular density and brightness of the thermal field electron source of the present application are more than 2 times higher than those of the traditional thermal field electron source.

[0143] It can be seen that compared with the traditional thermal field electron source, the thermal field emission electron source of this scheme has a smaller total emission Ie current, a larger angular density, and a higher brightness.

[0144] like Figure 8 As shown, the present invention provides a method for manufacturing a thermal field emission electron source in a third aspect, which comprises the following steps:

[0145] a. inserting the emission tip into a reaction solution in which an electrode ring is disposed;

[0146] b. connecting the emission tip and the electrode ring to form an energized circuit so that the emission tip undergoes electrochemical corrosion in the reaction solution;

[0147] c. Monitor the current parameters of the circuit in step b, and control the on and off of the circuit according to the current parameters to form a thermal field emission electron source.

[0148] The concave arc profile in this solution can be obtained through a physical, chemical or electrochemical corrosion process under precise control. By utilizing the particularity of the tooling, the corrosion / etching speed of the groove portion 201 is faster, and no manual operation is required, resulting in higher etching accuracy.

[0149] The method for manufacturing the thermal field emission electron source is described below in conjunction with some specific embodiments.

[0150] Example 1

[0151] The method for manufacturing the thermal field emission electron source in this embodiment comprises the following steps:

[0152] a. Insert the emission tip 0.1 mm below the liquid surface of the reaction solution; wherein the temperature of the reaction solution is 5°C, the extension portion 200 reacts more fully with the reaction solution, and is convenient for etching, and an electrode ring is provided in the reaction solution;

[0153] b. connecting the emission tip and the electrode ring to form an energized circuit so that the emission tip undergoes electrochemical corrosion in the reaction solution;

[0154] c. Monitor the current parameters of the circuit in step b, and control the on and off of the circuit according to the current parameters to form a thermal field emission electron source.

[0155] Example 2

[0156] The main difference between the method for preparing the thermal field emission electron source in this embodiment and the method for preparing the thermal field emission electron source in Example 1 lies in step a. In this embodiment, step a is to insert the emission tip 3 mm below the liquid surface of the reaction solution. The temperature of the reaction solution is 40°C. The remaining steps are similar to those in Example 1.

[0157] Example 3

[0158] The main difference between the method for preparing the thermal field emission electron source in this embodiment and the method for preparing the thermal field emission electron source in Example 1 is step a. In this embodiment, step a is to insert the emission tip 1 mm below the liquid surface of the reaction solution. The temperature of the reaction solution is 20°C. The remaining steps are similar to those in Example 1.

[0159] Optionally, in other embodiments, the depth of the emitting tip inserted below the liquid surface of the reaction solution is preferably 0.1-3 mm; similarly, the temperature of the reaction solution is preferably 5-40°C.

[0160] Furthermore, step c is specifically as follows: monitoring the current parameters of the circuit powered in step b, and transmitting the current parameters to the controller; when the current is lower than 1-20 mA, the controller automatically cuts off the circuit to form a thermal field emission electron source. The circuit current is monitored in real time, and the controller is used to automatically control the on and off of the circuit without manual operation.

[0161] Example 4

[0162] like Figure 8 , operate the mobile controller to move the electron source downward, enter the reaction solution (NaOH or KaOH aqueous solution), and go 0.1mm below the liquid surface, control the temperature of the reaction solution at 5°C, then turn on the computer, use the software to operate the programmable DC power supply, edit the power supply parameters, set the parameters of the waveform generator, connect the electron source and the electrode ring and power on, and electrochemical corrosion will occur in the reaction solution. The ADC collector monitors the current parameters in the circuit at all times. When the current is lower than 1mA, the circuit controller starts and cuts off the circuit to obtain the thermal field emission electron source applied by the present invention.

[0163] Example 5

[0164] like Figure 8 , operate the mobile controller to move the electron source downward, enter the reaction solution (NaOH or KaOH aqueous solution), 3mm below the liquid surface, control the temperature of the reaction solution at 40°C, then turn on the computer, use the software to operate the programmable DC power supply, edit the power supply parameters, set the parameters of the waveform generator, connect the electron source and the electrode ring and power on, and electrochemical corrosion will occur in the reaction solution. The ADC collector monitors the current parameters in the circuit at all times. When the current is lower than 20mA, the circuit controller starts and cuts off the circuit to obtain the thermal field emission electron source applied by the present invention.

[0165] Example 6

[0166] like Figure 8 , operate the mobile controller to move the electron source downward, enter the reaction solution (NaOH or KaOH aqueous solution), and go 1mm below the liquid surface, control the temperature of the reaction solution at 20°C, then turn on the computer, use the software to operate the programmable DC power supply, edit the power supply parameters, set the parameters of the waveform generator, connect the electron source and the electrode ring and power on, and electrochemical corrosion will occur in the reaction solution. The ADC collector monitors the current parameters in the circuit at all times. When the current is lower than 10mA, the circuit controller starts and cuts off the circuit to obtain the thermal field emission electron source applied by the present invention.

[0167] Fig. 9 and Fig.10It is an electron source emission test model established by simulation software, where Virtual source: virtual source; W or ZrO / W: tungsten or zirconium oxide / tungsten; suppressor: suppressor; anode: anode; Table 6 is the brightness parameter table obtained by ordinary thermal field emission electron source, which is basically E7A / cm 2 / sr level, Table 7 is the brightness data table calculated by the invention model of this application, close to E9A / cm 2 / sr level, it can be seen that the brightness index of the thermal field emission electron source in this application is nearly 2 orders of magnitude higher than that of the ordinary thermal field emission electron source. Fig.11 The emission brightness curve of the thermal field emission electron source provided by the present application is drawn, wherein Brightness: brightness; A / cm 2 / sr: ampere / square centimeter / solid angle; beam half angle (mrad): electron beam half angle (mrad).

[0168] Table 6 Brightness parameters obtained from common thermal field emission electron source

[0169]

[0170]

[0171] Table 7 Brightness parameters obtained by the thermal field emission electron source of this application

[0172]

[0173] The emission tip provided by the present application has an extension 200 that forms an inwardly concave arc profile. This structural design can make the electric field bend more strongly at the tip, so that the equipotential lines of the tip electric field are denser and the electric field strength is higher. In addition, at least one circle of grooves 201 is provided around the sidewall of the extension 200. The grooves 201 make the cylinder thinner in sections, slowing down the thinning speed and producing a buffering effect, so as to facilitate the migration rate of the zirconium mixture to be more stable during the migration process. The grooves 201 and the inwardly concave arc structure cooperate with each other to further optimize the distribution of the high-voltage electric field at the tip, improve the physical and chemical properties of the profile surface, and experiments have shown that it has achieved higher brightness, smaller total emission current and higher stability.

[0174] The present application also provides a thermal field emission electron source including the emission tip and a method for manufacturing the same. The thermal field emission electron source can be obtained through a physical, chemical or electrochemical corrosion process under precise control. By utilizing the particularity of the tooling, the corrosion / etching speed of the groove portion 201 is faster, and no manual operation is required, resulting in higher etching accuracy.

[0175] Although the embodiments of the present invention have been shown and described above, it is to be understood that the above embodiments are exemplary and are not to be construed as limitations of the present invention. A person skilled in the art may change, modify, replace and vary the above embodiments within the scope of the present invention.

Claims

1. A transmitting tip, characterized in that: It comprises a main body portion (100) and an extension portion (200); One end of the extension portion (200) is axially connected to the main body portion (100), and the other end extends axially in a direction away from the main body portion (100), and has a gradually shrinking first connection portion (202); Any axial cross section of the extension portion (200) is a pair of oppositely disposed at least one section of inwardly concave arc-shaped structures, and the side wall of the extension portion (200) is provided with at least one circle of groove portion (201); The extension portion (200) comprises the first connection portion (202) and the second connection portion which are integrally formed axially; the first connection portion (202) and the second connection portion are integrally formed by electrochemical corrosion, the second connection portion and the main body portion (100) are integrally formed by electrochemical corrosion, and the second connection portion is gradually reduced from the main body portion (100) toward the first connection portion (202), and the groove portion (201) is arranged on the second connection portion.

2. The emitting tip according to claim 1, characterized in that An emitting end is integrally formed axially at one end of the first connecting portion (202) away from the main body portion (100); the emitting end is a cylindrical structure, a conical structure or a table structure.

3. The emission tip according to claim 2, characterized in that On any axial cross section, with the midpoint of the tip of the first connecting portion (202) as the coordinate origin, in the first quadrant: The trajectory curve of the first connecting portion (202) is: y1 = 0.1191x 2 -0.1037x+0.7841; The trajectory curve of the groove portion (201) is: y2=0.1976x 2 -0.485x+20.926; Wherein, x is the distance from a point on the first connecting portion (202) or the groove portion (201) to the coordinate origin in the direction along the central axis of the main body portion (100); y1 is the shortest distance from a point on the first connecting portion (202) to the central axis; y2 is the shortest distance from a point on the groove portion (201) to the central axis; the units of x, y1 and y2 are all μm.

4. The emission tip according to claim 2, characterized in that On any axial cross section, with the midpoint of the tip of the first connecting portion (202) as the coordinate origin, in the first quadrant: The trajectory curve of the first connecting portion (202) is: y1 = 0.1617x 2 -0.2528x+0.7471; The trajectory curve of the groove portion (201) is: y2=0.1402x 2 +0.2643x+25.639; Wherein, x is the distance from a point on the first connecting portion (202) or the groove portion (201) to the coordinate origin in the direction along the central axis of the main body portion (100); y1 is the shortest distance from a point on the first connecting portion (202) to the central axis; y2 is the shortest distance from a point on the groove portion (201) to the central axis; the units of x, y1 and y2 are all μm.

5. The emission tip according to claim 2, characterized in that On any axial cross section, with the tip of the extension part (200) as the coordinate origin, in the first quadrant: The trajectory curve of the extension part (200) is: y=0.0872x 2 -0.2271x+2.7521; Wherein, x is the distance of a point on the extension portion (200) from the coordinate origin in the direction along the central axis of the main body portion (100); y is the shortest distance of a point on the extension portion (200) from the central axis; the units of x and y are both μm.

6. The emission tip according to claim 2, characterized in that On any axial cross section, with the midpoint of the tip of the first connecting portion (202) as the coordinate origin, in the first quadrant: The trajectory curve of the first connecting portion (202) is: y1 = 0.077x 2 -0.0048x+1.8974; The trajectory curve of the groove portion (201) is: y2=2.5193x 2 -12.739x+59.261; Wherein, x is the distance from a point on the first connecting portion (202) or the groove portion (201) to the coordinate origin in the direction along the central axis of the main body portion (100); y1 is the shortest distance from a point on the first connecting portion (202) to the central axis; y2 is the shortest distance from a point on the groove portion (201) to the central axis; the units of x, y1 and y2 are all μm.

7. A thermal field emission electron source comprising an emission tip according to any one of claims 1 to 6, characterized in that: Also included is a zirconized mixture (101) and a heating fork (300); The zirconium compound (101) is sleeved on the outer wall of the main body (100), and the distance between the zirconium compound (101) and the extension part (200) is less than or equal to 3 mm; The heating fork (300) is axially connected to one end of the main body (100), and the other end of the main body (100) is axially connected to the extension part (200).

8. The thermal field emission electron source according to claim 7, characterized in that: The zirconium compound at least comprises zirconium, and Th, Si, Ti and Ca elements distributed in sequence from the inside to the outside; Wherein, the contents of the Th element, the Si element, the Ti element and the Ca element are all 0.001%-1% of the total mass of the zirconium mixture.

9. A method for manufacturing a thermal field emission electron source according to claim 8, characterized in that: The following steps are involved: a. inserting the emission tip into the reaction solution, wherein the reaction solution is provided with an electrode ring; b. connecting the emission tip and the electrode ring to form an energized circuit so that the emission tip undergoes electrochemical corrosion in the reaction solution; c. Monitor the current parameters of the circuit in step b, and control the on and off of the circuit according to the current parameters to form the thermal field emission electron source.

10. The manufacturing method according to claim 9, characterized in that: Step a specifically comprises: inserting the emission tip into the reaction solution 0.1-3 mm below the liquid surface; wherein the temperature of the reaction solution is 5-40°C.

11. The manufacturing method according to claim 10, characterized in that: Step c specifically includes: monitoring the current parameters of the energized circuit in step b, and transmitting the current parameters to a controller; when the current is lower than 20 mA, the controller automatically cuts off the circuit to form the thermal field emission electron source.

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