CN109061232B - Atomic force microscope probe device - Google Patents

Abstract

The invention discloses a combined device of an atomic force microscope probe and a base, wherein a microcantilever of the probe has a stepped hole on the surface opposite to the needle tip; the probe base includes an adsorption part and a positioning part, and the adsorption part includes a vacuum adsorption groove and the adsorption surface; the positioning member extends from the adsorption surface and is inserted into the stepped hole and rotates to abut with the stepped surface of the stepped hole; the positioning member includes a connected rotating rod and a rotating bar, and an elastic component is installed on the upper surface of the rotating bar; the fine-tuning structure uses The connecting rod connects the rotating rod and the fine-tuning nut, and the fine-tuning nut controls the fine-tuning structure to drive the positioning piece to move. The device of the invention can improve the efficiency of needle changing, avoid needle dislocation and dislocation, and can apply a fixed force to the end of the probe micro-cantilever, thereby promoting the sensitivity of the probe micro-cantilever and improving the test effect.

Description

Atomic force microscope probe device

technical field

The invention relates to the technical field of semiconductor testing, in particular to a probe device of an atomic force microscope.

Background technique

Atomic Force Microscope (AFM) has been widely used in semiconductor sample testing. Its working principle is to study the extremely weak interatomic interaction force between the surface of the sample to be tested and a miniature force sensitive element (probe). The surface structure and properties of matter. Generally speaking, the probe includes a needle tip and a micro-cantilever. The end of the micro-cantilever, which is extremely sensitive to weak force, is fixed on the probe base, and the tip of the front-end of the micro-cantilever is close to the sample surface. When the distance between the needle tip and the sample surface is extremely small, a very weak attraction or repulsion force is generated between their atoms, which causes the microcantilever to deform or change its motion state. During the scanning process, the microcantilever with the needle tip will undulate in the direction perpendicular to the surface of the sample, and the state change of the microcantilever is collected by including the reflected laser beam and its photoelectric detection system, and the state change of the microcantilever is measured and the scanning point changes. Position correspondence, so as to obtain the physicochemical properties such as the surface structure of the material with atomic and molecular resolution.

However, since the tests of different physical and chemical properties require the use of different types of probes, the atomic force microscope often needs to replace the probes during use to complete the corresponding test requirements. During the needle exchange process, the replaced probe needs to be taken out, and the replaced probe needs to be put into the probe holder. However, since the probe is small and light, the operational difficulty of changing the needle is greatly increased. In the process of needle replacement, it is easy to waste new probes due to the misplacement of the probes or the drop in the middle, which increases the test cost, and if the probes fall off during the test process, it will affect the test process, and the staff needs to suspend the operation of the machine for inspection and maintenance. Atomic force microscope machine, which greatly increases the time cost.

At present, the common methods of placing the probe in the probe seat include clamping type, adsorption type, etc. When the probe is placed in the probe seat, the end of the probe is fixed by applying force. In the prior art, there is no concern and research on the influence of the tightness of the end of the atomic force microscope probe on the test effect.

SUMMARY OF THE INVENTION

The test effect of the atomic force microscope is closely related to the undulating motion of the probe cantilever, and the end of the probe cantilever is fixed on the probe base, and the tightness of the end of the probe cantilever restricts the undulating motion of the probe cantilever. The tightness of the end fixation deserves attention. The existing probe micro-cantilever end fixing device locks the probe end.

The main purpose of the present invention is to provide an atomic force microscope probe device capable of applying a fixed tightening force to the end of the probe micro-cantilever as needed, so as to apply a fixed force to the end of the probe micro-cantilever. The probe micro-cantilever end fixing device of the present invention reduces the installation difficulty of the probe, and largely avoids the needle drop phenomenon during the needle exchange process. In addition, the present invention can also effectively control the fixed state of the probe cantilever and improve its sensitivity, thereby improving the test effect of the physicochemical properties of the material surface.

In order to achieve the above object, the present invention provides an atomic force microscope probe and its base combination device, including a probe and a probe base, wherein the probe comprises a micro-cantilever and a needle tip based on one end of the micro-cantilever, the micro-cantilever is There is a step hole on the surface opposite to the needle tip; the probe seat includes an adsorption part and a positioning part, the adsorption part includes a vacuum adsorption groove and an adsorption surface, and the vacuum adsorption groove is used for applying adsorption force to the probe. to offset the gravity of the probe; the positioning member extends from the adsorption surface and is inserted into the stepped hole and rotates to contact the stepped surface of the stepped hole; the positioning member includes a connected rotating rod and a rotating bar, which rotates The rod is located in the middle of the rotating bar, and elastic components are installed on the upper surface of the rotating bar on both sides of the rotating rod. The elastic component is composed of a spring and a spring force sensing piece. The elastic force sensing piece is located at the top of the spring, and the end of the spring is fixed on the rotating bar On the upper surface; the fine-tuning structure uses a connecting rod to connect the rotating rod and the fine-tuning nut to form a tightening force adjusting structure, and the fine-tuning nut controls the fine-tuning structure to drive the positioning piece to move.

Preferably, the stepped hole is a two-stage stepped hole, including a small hole section and a large hole section.

Preferably, the positioning member includes a connected rotating rod and a rotating bar, wherein the maximum cross-sectional dimension of the rotating rod is smaller than the minimum cross-sectional size of the small hole segment; the cross-sectional shape of the rotating bar is the same as the size of the small hole segment. The shape of the section is matched, and the maximum size of the section is larger than the minimum size of the section of the small hole section and smaller than the minimum size of the section of the large hole section; the maximum size of the section is the maximum distance from each point on the outer periphery of the section to the center of rotation, The minimum dimension of the section is the minimum distance from each point on the outer periphery of the section to the center of rotation.

Preferably, the stepped hole is a rectangular hole, and the rotating bar is a rectangular bar.

Preferably, the positioning member includes the rotating rod and the rotating bar, the rotating rod is located in the middle of the rotating bar, and the elastic components are arranged on the upper surfaces of the rotating bars on both sides of the rotating rod, so The elastic components are arranged in an array.

Preferably, the fine-tuning nut is screwed for one turn, the lifting value of the positioning member is 0.01 mm, and the lifting range is not less than 2 mm.

The combined device of the probe and the base proposed by the present invention utilizes the vacuum adsorption device to offset the gravity of the probe and avoids the needle falling off during the needle changing process. The probe can be positioned on the probe seat, so that the dislocation of the probe caused by the small and light probe during the needle exchange process can be avoided, and the success rate of exchange between different probe needles is improved. By arranging an elastic component on the positioning member, the positioning member is driven to move by the fine-tuning structure, so as to control the degree of compression of the elastic component, thereby exerting a fixed force on the end of the probe micro-cantilever. The elastic component realizes the elastic fixation of the end of the probe micro-cantilever, promotes the sensitivity of the probe micro-cantilever, and improves the test effect.

Description of drawings

1 is a schematic structural diagram of an atomic force microscope probe and base combination device according to an embodiment of the present invention;

2 and 3 are a partial rear view and a partial cross-sectional view of a probe needle of an atomic force microscope according to an embodiment of the present invention;

4 is a perspective view of a positioning member in an atomic force microscope probe device according to an embodiment of the present invention.

Detailed ways

In order to make the content of the present invention clearer and easier to understand, the content of the present invention will be further described below with reference to the accompanying drawings. Of course, the present invention is not limited to this specific embodiment, and general substitutions known to those skilled in the art are also covered within the protection scope of the present invention.

Referring to FIGS. 1 to 4 , the atomic force microscope probe device provided in this embodiment includes a probe needle and a probe seat. The probe needle includes a micro-cantilever 110 fixed on the probe base and a needle tip 120 provided at one end of the micro-cantilever. If the surface of the micro-cantilever 110 with the needle tip 120 is set as the front surface, the surface opposite to the needle tip 120 is the back surface. In this embodiment, the micro-cantilever 110 is fixed in the probe holder by vacuum adsorption. Specifically, the probe base includes an adsorption member 210, the adsorption member has an adsorption surface S, and an air guide groove C is opened on the adsorption surface S. The air guide groove C is communicated with the air guide pipe 220, and the negative pressure generated by the vacuuming part is used to offset The self-gravity of the probe makes the back of the micro-cantilever 110 adsorb on the adsorption surface S to prevent the needle from falling off during the needle changing process.

On the other hand, in order to fix the probe, a fixed force is applied to the end of the probe microcantilever to effectively control the undulating motion amplitude of the probe microcantilever, thereby improving the test effect. The probe seat of the present invention further includes a positioning member 230 extending downward from the adsorption surface S, and the probe needle is also provided with a stepped hole 130 corresponding to the positioning member. By inserting the positioning member 230 into the stepped hole from the back of the micro-cantilever 130 and rotate to make the positioning member 230 abut against the stepped surface of the stepped hole 130, so as to further fix the probe needle. The positioning member 230 includes a rotating rod 230a and a rotating bar 230b. The rotating rod 230a is located in the middle of the rotating bar 230b, and elastic components 230c are arranged on the upper surfaces of the rotating bars 230b on both sides of the rotating rod 230a. The elastic components 230c are arranged in an array. The elastic component 230c is composed of a spring and an elastic force sensing piece, the elastic force sensing piece is located at the top end of the spring, and the end of the spring is fixed on the upper surface of the rotating bar 230b. The fine-tuning structure 240 is disposed in the adsorption member 210 , and the connecting rod 260 is used to connect the rotating rod 230 a , the fine-tuning nut 250 and the rotating rod 230 a . Thereby, the purpose of applying a fixed force to the end of the probe micro-cantilever and controlling the undulating motion range of the probe micro-cantilever is achieved, and the test effect is improved.

The positioning method of the probe device of this embodiment will be described in detail below.

Referring to FIGS. 2-3 , stepped holes 130 are formed on the backside of the micro-cantilever 110 . In this embodiment, the stepped hole 130 is a two-stage rectangular stepped hole, including a small hole section 130a with a smaller cross-sectional size and a large hole section 130b with a larger cross-sectional size. Correspondingly, the maximum cross-sectional dimension of the rotating rod 230a is smaller than the minimum cross-sectional dimension of the small hole section 130a, so that it can be freely inserted into the stepped hole; while for the rotating bar 230b, it can be inserted into the small hole section of the stepped hole, but The maximum cross-sectional dimension of the rotating bar 230b is larger than the minimum cross-sectional dimension of the small hole section 130a and smaller than the minimum cross-sectional dimension of the large hole section 130b, so that when the positioning member 230 is inserted into the stepped hole 130 to a certain depth, all the rotating bars 230b are located in the large hole section 130b middle. The rotating bar 230b can rotate freely in the large hole section 130b, and after rotating a certain angle, the larger dimension of its cross-section will abut on the stepped surface of the stepped hole 130, so that the positioning member is engaged in the stepped hole. Preferably, the cross-sectional shape of the rotating bar 230b matches the cross-sectional shape of the small hole section 130a, and can be inserted into the small hole section 130a more conveniently. The maximum size of the section mentioned here refers to the maximum distance from each point on the outer periphery of the section to the center of rotation, while the minimum size of the section refers to the minimum distance from each point on the outer periphery of the section to the center of rotation.

Next, the needle exchange and force application process of the atomic force microscope probe device of this embodiment will be described.

In this embodiment, the stepped hole 130 is a rectangular stepped hole, the rotating bar 230b is a slightly smaller rectangular bar that matches the shape of the small hole section, and the cross section of the rotating rod 230a is square. First, align the air guide groove 220 of the probe base with the back of the micro-cantilever 110, and use the vacuuming component to generate a negative pressure to offset the self-gravity of the probe, so that the back of the micro-cantilever 110 is adsorbed on the adsorption surface S to prevent the needle change during the needle changing process. Needle off. Next, move the probe along the adsorption surface S to the position of the probe seat positioning member 230 , and insert the positioning member 230 into the stepped hole 130 . At this time, the probe seat and the micro-cantilever 110 also form a certain angle. Afterwards, the positioning member 230 is rotated relative to the micro-cantilever 110 at a certain angle, while the long side of the rotating bar 230b crosses the long side of the rectangular hole section 130a so that the elastic components on the rotating bar 230b contact the stepped surface. At this point, the positioning of the probe needle and the probe base is completed. Finally, the fine-tuning nut 250 is adjusted to regulate the fine-tuning structure 240, and the fine-tuning structure 240 drives the positioning member 23 to move along the direction perpendicular to the adsorption surface S to control the degree of compression of the elastic component 230c, and the elastic force sensor sheet transmits the pressure at each position to the control end and display. The fixed force is applied to the end of the micro-cantilever with the average value of the pressure on the elastic force sensing sheet. During the test, the vacuuming part is closed, and the elastic component 230c of the device is used to realize the elastic fastening of the end of the micro-cantilever, which improves the vibration effect of the micro-cantilever.

To sum up, the combined device of the probe and the base proposed by the present invention utilizes the vacuum adsorption device to offset the gravity of the probe, which can effectively avoid the needle-drop phenomenon during the needle-changing process. By arranging a positioning member on the probe seat and a corresponding step hole on the probe needle, the probe can be positioned on the probe seat, which can avoid the dislocation of the probe caused by the small and light probe during the needle change process, and improve the performance of the probe. success rate during probe replacement. By arranging an elastic component on the positioning member, the positioning member is driven to move by the fine-tuning structure, so as to control the degree of compression of the elastic component, thereby exerting a fixed force on the end of the probe micro-cantilever. The elastic component realizes the elastic fixation of the end of the probe micro cantilever, effectively controls the fixed state of the probe cantilever, improves its sensitivity and improves the test effect.

Although the present invention has been disclosed above with preferred embodiments, the above-mentioned embodiments are only examples for the convenience of description and are not intended to limit the present invention. Those skilled in the art can With some changes and modifications, the protection scope claimed by the present invention should be based on the claims.

Claims (7)

1. An atomic force microscope probe and base combination device comprises a probe, a probe base and a positioning piece, wherein the probe comprises a micro-cantilever and a needle point arranged at one end of the micro-cantilever, and a step hole is formed on the surface of the micro-cantilever opposite to the needle point; the probe seat comprises an adsorption piece, a vacuum pumping part and a probe seat, wherein the adsorption piece is provided with an adsorption surface, and the adsorption surface is provided with an air guide groove communicated with the vacuum pumping part and used for providing adsorption force for the probe to offset the gravity of the probe; the positioning piece extends out of the adsorption surface downwards and is inserted into the stepped hole and rotates to enable the positioning piece to be in contact with the stepped surface of the stepped hole; the setting element is including continuous dwang and rotation strip, its characterized in that: the upper surface of the rotating strip is provided with an elastic component; the elastic assembly consists of a spring and an elastic sensing piece, the elastic sensing piece is positioned at the top end of the spring, and the tail end of the spring is fixed on the upper surface of the rotating strip;

the elastic sensing piece transmits the pressure at each position to the control end, and the average value of the pressure of the elastic sensing piece is used as the tail end of the micro cantilever to apply fixed acting force;

in the testing process, the vacuumizing part is closed, the elastic component of the device is utilized to realize elastic fastening of the tail end of the micro cantilever, and the vibration effect of the micro cantilever is improved;

still include fastening power adjustment structure, fastening power adjustment structure includes: the fine adjustment structure is connected with the rotating rod and the fine adjustment nut through the connecting rod, and the fine adjustment structure is controlled by the fine adjustment nut to drive the positioning piece to move.

2. The afm probe and base assembly of claim 1, wherein the stepped bore is a two-step bore comprising a small bore section and a large bore section.

3. The afm probe and mount assembly of claim 2, wherein the positioning member comprises a rotating rod and a rotating strip connected to each other, wherein a maximum cross-sectional dimension of the rotating rod is smaller than a minimum cross-sectional dimension of the small hole segment; the cross section of the rotating strip is matched with that of the small hole section, and the maximum cross section size of the rotating strip is larger than the minimum cross section size of the small hole section and smaller than the minimum cross section size of the large hole section; the maximum size of the section is the maximum distance from each point on the periphery of the section to the rotation center, and the minimum size of the section is the minimum distance from each point on the periphery of the section to the rotation center.

4. The afm probe and base assembly of claim 3, wherein the stepped bore is a rectangular bore and the rotating strip is a rectangular strip.

5. The AFM probe and base assembly of claim 4, wherein the positioning member comprises a rotating rod and a rotating strip, the rotating rod is located in the middle of the rotating strip, the elastic members are disposed on the upper surfaces of the rotating strip on two sides of the rotating rod, and the elastic members are arranged in an array.

6. The AFM probe and base assembly of claim 5, wherein the fine tuning nut is screwed for one turn, the positioning element has a height of 0.01mm, and the height is not less than 2 mm.

7. A method of installing and using the afm probe and base assembly of claim 1, comprising:

step 1, aligning an air guide groove of a probe seat to the back of a micro-cantilever, and utilizing a vacuum pumping part to generate negative pressure to counteract the self gravity of the probe so as to prevent needle drop in the needle changing process; step 2, translating the probe to the position of a positioning piece of the probe seat along the adsorption surface S, and inserting the positioning piece into the step hole, wherein a certain included angle is formed between the probe seat and the micro cantilever; step 3, rotating the positioning piece for a certain angle relative to the micro-cantilever, and enabling the long edge of the rotating strip to be crossed with the long edge of the rectangular small hole section to enable the elastic assembly on the rotating strip to be abutted against the step surface, so that the positioning of the probe and the probe seat is completed; step 4, adjusting the fine tuning nut, controlling the fine tuning structure, driving the positioning piece to move along the direction vertical to the adsorption surface, controlling the compression degree of the elastic component, transmitting the pressure at each position to the control end by the elastic sensing piece, and taking the average value of the pressure of the elastic sensing piece as the tail end of the micro cantilever to apply a fixed acting force; and 5, in the testing process, closing the vacuumizing part, and elastically fastening the tail end of the micro cantilever by using the elastic component, so that the vibration effect of the micro cantilever is improved.

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