CN212570921U - Plasma cleaning device for precision electron microscope analytical instrument - Google Patents

Abstract

The utility model discloses a plasma belt cleaning device for accurate electronic speculum analytical instrument, including electronic speculum analytical instrument cavity, electronic speculum analytical instrument cavity respectively with the vacuum gauge, the RGA analyzer, QCM membrane thickness control appearance and aspiration pump are connected, electronic speculum analytical instrument cavity still is connected with plasma generator, be provided with Langmuir's probe on plasma generator's the output and the connecting tube between the electronic speculum analytical instrument cavity, the plasma parameter for production when measuring plasma generator discharges, the top of plasma generator output is provided with the air leak valve, plasma generator's input passes through the radio frequency line and is connected with the radio frequency source main part. The plasma cleaning device for the precision electron microscope analytical instrument can select proper discharge power according to the type and the size of a cleaning cavity as required, thereby achieving the purpose of cleaning pollutants and having stronger applicability; the inside of the cavity is cleaned by adopting the plasma generated by the excitation of the radio frequency source, and the inner wall of the cleaning cavity is not damaged.

Description

Plasma cleaning device for precision electron microscope analytical instrument

Technical Field

The utility model belongs to the technical field of plasma belt cleaning device, concretely relates to plasma belt cleaning device for accurate electron microscope analytical instrument.

Background

In electron microscopy systems, lubricating oils, vacuum greases, high vapor pressure polymers and photoresist samples may introduce hydrocarbon contamination into the system. XPS data clearly shows that clean sample surfaces exposed to air are contaminated with airborne hydrocarbon material after only one hour. For high resolution SEM systems, the high resolution of the system is derived from secondary electron imaging, the secondary electrons coming primarily from the thin film surface layer of the sample. Thus, if the surface is contaminated, the electrons come primarily from the contaminated layer, not the underlying target material. With the continuous progress of scientific research, people have higher and higher requirements on an ultrahigh vacuum system, the ultrahigh vacuum system is a main part for carrying out modern surface analysis and research, generally, an ultrahigh vacuum chamber, a related air exhaust pipeline and the like are generally made of stainless steel materials, and flanges with knife edges and copper gaskets are used for sealing the mutual connection parts.

If the vacuum chamber is seriously polluted by hydrocarbon, the sample is irradiated by high-dose electron beams for a long time, a black frame is formed on the surface of the sample, the black frame is mainly caused by polymer carbon deposition, the carbon deposition is mainly caused by that when the high-energy electron beams hit the surface of the sample, a large amount of low-energy secondary electrons are generated, the secondary electrons can interact with organic pollutants remained on the surface of the sample due to low kinetic energy, the secondary electrons decompose the organic pollutants and form carbon deposition (carbon and hydrocarbon pollutants) around an imaging area, unstable charging conditions can be generated in an electron optical lens barrel due to the poor conductor of the hydrocarbon pollutants, the charges accumulated on the surface can be increased continuously along with the increase of the carbon deposition, the focus and the position of a light beam can drift during long-time scanning, and the local charging can increase the aberration of the lens and reduce the resolution, resulting in an inability to image clearly.

X-rays analyze the composition of the material and a high dose of electron beam will irradiate the sample surface for a longer period of time. If the vacuum chamber is heavily contaminated with hydrocarbons, the carbon build-up will increase and will be higher than the actual percentage in the sample material. Two components in electron optics are exposed to high dose electron irradiation for a long time, and the diaphragm limits the beam angle and controls the beam current by blocking large-angle electrons, and can also be used as a dimmer. A scanning electron detector is used to collect the emitted secondary electrons. Neither of these electro-optical components is in an ultra-high vacuum region, and if the cavity is contaminated, they are susceptible to severe hydrocarbon accumulation. Meanwhile, inorganic pollutants are inevitably attached to the surface of the sample and the end part of the sample rod in the process of preparing the sample, and the pollutants enter the vacuum sample cavity along with the sample, so that the resolution of the imaging of the sample is influenced, and even the whole sample cavity is polluted, and therefore, the sample needs to be cleaned before the sample is subjected to electron microscope testing.

Traditional electron microscope analytic system's washing adopts organic solvent more, and organic solvent can remain on the one hand on the sample surface, also can cause the pollution to the environment simultaneously, consequently to above-mentioned problem, plasma cleaning technique has appeared, and plasma cleaning mainly relies on the "activation" of the active free radical that plasma discharge in-process produced to remove the impurity on object surface, through gaseous phase chemical reaction, organic pollutant and greasy dirt are converted into gaseous water and carbon dioxide, and these gases can be taken away by the vacuum pump. Since the plasma generated in the discharge is anisotropic, it can penetrate into the inside of the micro-holes and depressions of the object to complete the cleaning task. The necessity of using ultra-high vacuum in surface analysis techniques: first, the low-energy electron signal to be analyzed is easily scattered by the residual gas molecules, so that the total signal of the spectrum is weakened, and only under the condition of ultrahigh vacuum, the low-energy electrons can obtain a long enough mean free path without being lost by scattering. Second, the ultra-high vacuum environment is necessary for the surface sensitivity of the surface analysis technique itself. At a high vacuum of 1e-6mbar, a monolayer of gas is adsorbed on the solid surface for about 1 second, which is too short compared to typical spectra acquisition times, and it is clear that an ultra-high vacuum environment is required to keep the sample surface clean during the analysis. Finally, surface sensitive analysis techniques require much higher cleanliness of the sample surface than other analysis techniques, and the preparation and maintenance of clean surfaces is essential, and surface analysis needs to be performed in Ultra High Vacuum (UHV) to ensure that the surface is not contaminated during the analysis process.

In order to ensure that the system reaches the required vacuum degree, the inner surface of the vacuum pipeline must be ensured to be clean, and at present, a plurality of methods for cleaning the vacuum pipeline exist, and a common method is to combine mechanical wire drawing polishing and chemical cleaning. These methods have their disadvantages. For example, mechanical wire-drawing polishing is easy to cause abrasion on the surface of an object to be cleaned, is labor-intensive, requires equipment to stop working, and cannot meet the requirement of high-cleanliness cleaning. Although the chemical cleaning method can prevent the surface of an object from being abraded, the chemical cleaning method has the defects that if the chemical cleaning solution is not properly selected, the cleaning object is corroded and damaged, and loss is caused; and the discharge of waste liquid generated by chemical cleaning is also one of the causes of environmental pollution, and the improper operation and treatment of chemical agents can cause harm to the health and safety of people.

In view of the above problems, a plasma cleaning technique has been developed, which is characterized in that it can process metal, semiconductor, oxide and most of high polymer materials (such as polyethylene, polyvinyl chloride, polytetrafluoroethylene, poly look down vinylidene, poly vinegar, epoxy resin and other polymers) without dividing the type of the substrate to be processed, and can achieve plasma cleaning of the whole, local and complex structure. Plasma cleaning mainly relies on the "activation" of the active radicals generated during plasma discharge to remove impurities from the surface of the object, organic pollutants and oil are converted into gaseous water and carbon dioxide by gas phase chemical reactions, and these gases can be pumped away by a vacuum pump. Since the plasma generated in the discharge is anisotropic, it can reach deep into the inside of the micro-holes and depressions of the object to perform the cleaning task, and thus there is no need to consider the shape of the wall of the object too much.

From all kinds of cleaning methods at present, plasma washs the mode of washing of the most thorough peel-off formula among all cleaning methods, however, general plasma washing that discharges generally adopts direct current and low frequency discharge excitation plasma more, and the physics effect of mainly using is used for cleaing away the inside steam of cavity, and the power of adoption is less, and the plasma of this kind of mode excitation causes the damage to the sample surface easily, and the concurrent operation is complicated, is unsuitable to wash precision analysis instrument such as electron microscope, the utility model relates to a problem that precision electron microscope analytical instrument exists is washd to present plasma technique, utility model relates to a plasma cleaning device for precision electron microscope analytical instrument solves above-mentioned problem, the demand that satisfies the numerous technical staff of bigger degree.

SUMMERY OF THE UTILITY MODEL

An object of the utility model is to provide a plasma belt cleaning device for accurate electron microscope analytical instrument to solve the problem that proposes among the above-mentioned background art.

In order to achieve the above object, the utility model provides a following technical scheme: the utility model provides a plasma belt cleaning device for accurate electronic speculum analytical instrument, includes electronic speculum analytical instrument cavity, electronic speculum analytical instrument cavity is connected with vacuum gauge, RGA analyzer, QCM membrane thickness control appearance and aspiration pump respectively, electronic speculum analytical instrument cavity still is connected with plasma generator, be provided with the Langmuir probe on the connecting tube between plasma generator's the output and the electronic speculum analytical instrument cavity for the plasma parameter that produces when measuring plasma generator discharges.

And the top of the output end of the plasma generator is provided with an air leakage valve, and the input end of the plasma generator is connected with the radio frequency source main body through a radio frequency line.

Preferably, the radio frequency source main part includes the shell, the surface of shell is provided with the louvre, the inside base that is provided with of shell, the base sets up with the shell is fixed, the upper surface of base is fixed with DC power supply and radio frequency source respectively, DC power supply's one end is provided with the power supply mouth, the one end in radio frequency source is provided with the radio frequency source delivery outlet, the surface of shell is opened there is the opening for radio frequency source delivery outlet, power supply mouth stretch out from the shell.

Preferably in any one of the above schemes, the base includes a bottom plate matched with one side of the housing, side plates are vertically arranged around the bottom plate, bolt holes are arranged on the surface of the side plates, the bolt holes of the side plates correspond to the bolt holes on the surface of the housing, and the side plates are fixedly connected with the housing through bolts.

Preferably in any of the above schemes, a fan is disposed inside the housing at a position close to the radio frequency source, bolt holes are disposed at four vertex angles of the fan, a heat dissipation port is disposed on the surface of the housing, and mounting holes corresponding to the bolt holes of the fan are disposed at the four vertex angles of the heat dissipation port, and the mounting holes are used for being fixedly connected with the fan bolts.

In any of the above schemes, preferably, the plasma generator includes a plasma generator main body, one end of the plasma generator main body is provided with a radio frequency line connector connected with a radio frequency line, the other end of the plasma generator main body is provided with a mounting seat, an air leakage valve interface is opened on the surface of the mounting seat and is used for being connected with an air leakage valve, a fastening bolt is arranged in the mounting seat above the air leakage valve interface, a mounting hole at one end of the mounting seat is connected with a sealing flange through a bolt, and the sealing flange is connected with the mounting seat and a connecting pipeline.

In any one of the above aspects, preferably, the surface of the plasma generator main body is provided with a heat dissipation channel.

In any of the above aspects, preferably, two generation chambers are provided inside the plasma generator main body, and the two generation chambers are separated by a coupler.

The utility model discloses a technological effect and advantage: 1. the plasma cleaning device for the precision electron microscope analytical instrument can select proper discharge power according to the type and the size of a cleaning cavity as required, thereby achieving the purpose of cleaning pollutants and having stronger applicability;

2. the inside of the cavity is cleaned by adopting plasma generated by excitation of a radio frequency source, so that the inner wall of the cleaning cavity is not damaged;

3. the active free radicals of the radio frequency plasma are utilized to react with organic pollutants to generate volatile CO and CO₂The volatile gas (hydrocarbon) can be pumped by a vacuum pump, so that the purpose of cleaning pollutants is achieved, the operation is simple, and the use is convenient;

4. different discharge gases and electrode materials can be selected according to the type and the pollution degree of the pollutants in the cavity, so that the pollutants can be effectively removed, and the cavity and the sample can be cleaned;

5. the cleaning of the ultrahigh vacuum precision electron microscope analytical instrument can be realized, and the time required for reaching ultrahigh vacuum can be effectively shortened through the cavity cleaned by the plasma.

Drawings

Fig. 1 is a schematic structural view of the present invention;

fig. 2 is a schematic structural diagram of the rf source body according to the present invention;

fig. 3 is a schematic structural diagram of another view angle of the rf source body according to the present invention;

fig. 4 is a schematic view of the internal structure of the rf source body according to the present invention;

FIG. 5 is a schematic structural view of the plasma generator of the present invention;

fig. 6 is a schematic structural view of another view angle of the plasma generator according to the present invention;

fig. 7 is a schematic structural view of the mounting base of the present invention;

fig. 8 is a schematic structural view of the inside of the mounting base of the present invention;

FIG. 9 is a schematic view of the connection structure between the air leak valve and the plasma generator according to the present invention;

fig. 10 is an enlarged schematic view of part a of the present invention;

fig. 11 is a sectional view of the inside of the plasma generator according to the present invention.

In the figure: 1. a radio frequency source body; 11. a housing; 12. heat dissipation holes; 13. a power supply port; 14. an RF source output port; 15. a fan; 16. a base; 17. a radio frequency source; 18. a direct current power supply; 19. a heat dissipation port; 2. A radio frequency line; 3. a plasma generator; 31. a mounting seat; 32. sealing the flange; 33. a heat dissipation channel; 34. A radio frequency line connector; 35. fastening a bolt; 36. mounting holes; 37. a coupler; 38. an air leakage valve interface; 39. a plasma generator main body; 5. langmuir probe; 6. a cavity of an electron microscope analysis instrument; 7. a vacuum gauge; 8. an RGA analyzer; 9. QCM film thickness control instrument; 10. an air pump.

Detailed Description

The following describes the present invention with reference to the accompanying drawings. It should be noted that the description of the embodiments is provided to help understanding of the present invention, but the present invention is not limited thereto. In addition, the technical features related to the embodiments of the present invention described below may be combined with each other as long as they do not conflict with each other.

In the description of the present invention, it is to be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", and the like, indicate the orientation or positional relationship indicated based on the drawings, and are only for convenience of description and simplicity of description, and do not indicate or imply that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore, should not be construed as limiting the present invention.

Furthermore, the terms "first", "second" and "first" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one such feature. In the description of the present invention, "a plurality" means at least two, e.g., two, three, etc., unless specifically limited otherwise.

The utility model provides a plasma cleaning device for precision electron microscope analytical instrument as shown in figures 1-11, which comprises an electron microscope analytical instrument cavity 6, the electron microscope analytical instrument cavity 6 is respectively connected with a vacuum gauge 7, an RGA analyzer 8, a QCM film thickness controller 9 and an air pump 10, the vacuum gauge 7, the RGA analyzer 8, the QCM film thickness controller 9 and the air pump 10 all adopt the prior art equipment, the vacuum gauge 7, the RGA analyzer 8 and the QCM film thickness controller 9 are all connected to the electron microscope analytical instrument cavity 6 by adopting a copper gasket sealing flange, the vacuum gauge 7 can effectively detect the discharge air pressure in the electron microscope analytical instrument cavity 6 when the discharge is carried out, the RGA analyzer 8 can effectively analyze the component change of residual gas in the electron microscope analytical instrument cavity 6 before and after the plasma cleaning, the QCM film thickness controller 9 can effectively monitor the cleaning rate in the electron microscope analytical instrument cavity 6, the cavity 6 of the electron microscope analysis instrument is also connected with a plasma generator 3, a connecting pipeline of the cavity 6 of the electron microscope analysis instrument is connected to the cavity 6 of the electron microscope analysis instrument through a sealing flange 32, a Langmuir probe 5 is arranged on the connecting pipeline between the output end of the plasma generator 3 and the cavity 6 of the electron microscope analysis instrument and is used for measuring plasma parameters generated when the plasma generator 3 discharges, an air leakage valve 4 is arranged at the top of the output end of the plasma generator 3, the input end of the plasma generator 3 is connected with a radio frequency source main body 1 through a radio frequency line 2, the radio frequency source main body 1 comprises a shell 11, at least two surfaces of the shell 11 are provided with heat dissipation holes 12, a base 16 is arranged inside the shell 11, the base 16 is fixedly arranged with the shell 11, the base 16 comprises a bottom plate matched with one side of the shell 11, side plates are vertically arranged, the surface of two opposite side plates is provided with bolt holes which are arranged corresponding to the bolt holes on the surface of the shell 11, the side plates are fixedly connected with the shell 11 through bolts, the upper surface of the base 16 is respectively fixed with a direct current power supply 18 and a radio frequency source 17, the fixing mode is bolt connection, glue connection and fixed connection except two connection modes, one end of the direct current power supply 18 is provided with a power supply port 13, the power supply port 13 is fixed with the shell 11 through bolts, the power supply port 13 is electrically connected with the direct current power supply 18 through an electric wire, one end of the radio frequency source 17 is provided with a radio frequency source output port 14, the surface of the shell 11 is provided with an opening for the radio frequency source output port 14 and the power supply port 13 to extend out of the shell 11, the position inside the shell 11 close to the radio frequency source 17 is provided with a fan 15, the bolt holes are arranged at four vertex angles of the fan 15, and the four apex angles of the heat dissipation port 19 are provided with mounting holes corresponding to the bolt holes of the fan 15, so as to be fixedly connected with the fan 15 through bolts, and the fan 15 is connected with the shell 11 through bolts, so that the use process is more stable, and the disassembly is convenient.

Specifically, referring to fig. 5-8, the plasma generator 3 includes a plasma generator main body 39, a heat dissipation channel 33 is disposed on the surface of the plasma generator main body 39, and at least one side of the heat dissipation channel 33 is disposed, the heat dissipation channel 33 is disposed to enable heat generated by the plasma generator 3 to be dissipated in time during operation, so as to maintain stability in use and service life, two generation chambers are disposed inside the plasma generator main body 39 and separated by a coupler 37, a radio frequency line connector 34 connected to a radio frequency line 2 is disposed at one end of the plasma generator main body 39, the radio frequency line connector 34 is provided with at least 2 radio frequency lines, a mounting seat 31 is disposed at the other end of the plasma generator main body 39, an air leakage valve interface 38 is opened on the surface of the mounting seat 31 for connecting with the air leakage valve 4, a fastening bolt 35 is disposed in the mounting seat 31 above the air leakage valve interface 38, the air leakage valve joint 42 for fixing the air leakage valve 4 is fixed at the air leakage valve interface 38, the mounting hole 36 at one end of the mounting seat 31 is connected with the sealing flange 32 through a bolt, and the sealing flange 32 is connected with the mounting seat 31 and the connecting pipeline.

Wherein the air leak valve 4 is used for leaking gas, the air leak valve 4 mainly includes the air leak valve main part, air leak valve main part one end is provided with the air leak valve and connects, the one end that the air leak valve connects is most advanced, through screw thread and fastening bolt 35 thread tightening, the bore of air leak valve interface 38 is greater than the most advanced diameter that the air leak valve connects, be not greater than the diameter that the air leak valve connects, make the most advanced of air leak valve joint insert in the air leak valve interface 38, the air leak valve joint that the screw position begins is located the outside of air leak valve interface 38, it makes the screw thread and the fastening bolt 35 inner wall spiro union of air leak valve joint to rotate the air leak valve main part.

The plasma cleaning device for the precise electron microscope analysis instrument is characterized in that in the using process, a vacuum gauge 7, an RGA analyzer 8, a QCM film thickness controller 9 and an air pump 10 are installed on a cavity 6 of the electron microscope analysis instrument, air tightness is ensured at the same time, a plasma generator 3 is connected to a connecting pipeline extending out of the cavity 6 of the electron microscope analysis instrument, a Langmuir probe 5 is connected to the connecting pipeline, an air leakage valve 4 is fixed on a mounting seat 31 of the plasma generator 3, the plasma generator 3 is connected with a radio frequency source main body 1 through a radio frequency line 2, the radio frequency source main body 1 is opened and closed during cleaning, the radio frequency source main body 1 acts on the plasma generator 3 to excite and generate plasma, and the plasma reacts with organic pollutants on the inner wall of the cavity 6 of the electron microscope analysis instrument to generate volatile CO and CO₂The gas (hydrocarbon), these volatile gases are pumped away through the air pump 10, realize the cleaning to the electron microscope analysis instrument cavity 6, according to the pollutant that needs cleaning, choose different cleaning gases, such as air, oxygen, nitrogen, argon, etc., but not limited to above-mentioned gas, the radio frequency source body 1 can also be selected, the radio frequency source of the high power, use the special radio frequency chip amplifier, the low voltage drive of 24V, 200 and 500MHz discharge frequency can be selected, dischargeThe power of 100-.

Although embodiments of the present invention have been shown and described, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention, and that variations, modifications, substitutions and alterations can be made to the above embodiments by those of ordinary skill in the art without departing from the scope of the present invention.

Claims (7)

1. The utility model provides a plasma belt cleaning device for accurate electron microscope analytical instrument, includes electron microscope analytical instrument cavity (6), electron microscope analytical instrument cavity (6) are connected its characterized in that with vacuum gauge (7), RGA analyzer (8), QCM membrane thickness control appearance (9) and aspiration pump (10) respectively: the electron microscope analysis instrument cavity (6) is also connected with a plasma generator (3), and a Langmuir probe (5) is arranged on a connecting pipeline between the output end of the plasma generator (3) and the electron microscope analysis instrument cavity (6);

an air leakage valve (4) is arranged at the top of the output end of the plasma generator (3), and the input end of the plasma generator (3) is connected with the radio frequency source main body (1) through a radio frequency wire (2).

2. The plasma cleaning device for the precision electron microscope analysis instrument according to claim 1, wherein: radio frequency source main part (1) includes shell (11), the surface of shell (11) is provided with louvre (12), shell (11) inside is provided with base (16), base (16) and shell (11) fixed setting, the upper surface of base (16) is fixed with DC power supply (18) and radio frequency source (17) respectively, the one end of DC power supply (18) is provided with power supply port (13), the one end of radio frequency source (17) is provided with radio frequency source delivery outlet (14), open on the surface of shell (11) has the opening for stretch out in radio frequency source delivery outlet (14), power supply port (13) follow shell (11).

3. The plasma cleaning device for the precision electron microscope analysis instrument according to claim 2, wherein: the base (16) comprises a bottom plate matched with one side of the shell (11), side plates are vertically arranged on the periphery of the bottom plate, bolt holes are formed in the surfaces of the side plates, the bolt holes of the side plates correspond to the bolt holes in the surface of the shell (11), and the side plates are fixedly connected with the shell (11) through bolts.

4. The plasma cleaning device for the precision electron microscope analysis instrument according to claim 2, wherein: the inside position that is close to radio frequency source (17) of shell (11) is provided with fan (15), four apex angle departments of fan (15) are provided with the bolt hole, the surface of shell (11) is provided with thermovent (19), and four apex angle departments of thermovent (19) are provided with the mounting hole that corresponds with the bolt hole of fan (15) for with fan (15) bolt fixed connection.

5. The plasma cleaning device for the precision electron microscope analysis instrument according to claim 1, wherein: plasma generator (3) include plasma generator main part (39), the one end of plasma generator main part (39) is provided with radio frequency line connector (34) of being connected with radio frequency line (2), the other end of plasma generator main part (39) is provided with mount pad (31), leak pneumatic valve interface (38) have been opened on the surface of mount pad (31) for be connected with leak pneumatic valve (4), be provided with fastening bolt (35) corresponding to the top of leak pneumatic valve interface (38) in mount pad (31), mounting hole (36) of mount pad (31) one end are connected with sealing flange (32) through the bolt, and sealing flange (32) are connected mount pad (31) and connecting tube.

6. The plasma cleaning device for the precision electron microscope analysis instrument according to claim 5, wherein: the surface of the plasma generator main body (39) is provided with a heat dissipation channel (33).

7. The plasma cleaning device for the precision electron microscope analysis instrument according to claim 6, wherein: the interior of the plasma generator main body (39) is provided with two generating chambers which are separated by a coupler (37).

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