Ion microscope and focused ion beam system with single optical device

Abstract

The ion microscope and focused ion beam system with single optical device includes a vacuum chamber, an emitter, a gas pressure control device, an optical device, a voltage control module and a signal control module. The emitter, the optical device and a sample are disposed in an inner space of the vacuum chamber. The gas pressure control device stores a gas and is connected to a chamber wall of the vacuum chamber. The voltage control module is electrically connected to the emitter and the optical device to generate a draw voltage on the emitter and a bias voltage on the optical device. The signal control module is connected to the gas pressure control device and the voltage control module to generate a gas introduction control signal to cause the gas pressure control device to introduce the gas into the inner space, and to adjust the output bias voltage and the draw voltage to cause the emitter to generate a heavy ion beam and a light ion beam.

Description

Technical Field

[0001] This invention relates to an ion beam system with optical devices, and more particularly to an ion microscope and a focused ion beam system with a single optical device. Background Technology

[0002] Please see Figure 2 This is a schematic diagram of a conventional dual-beam focused ion beam system. Modern focused ion beam (FIB) systems play an indispensable role in semiconductor fault analysis and circuit repair. Currently, the commonly used dual-beam FIB (DB-FIB) system mainly consists of two optical columns 21 and 22. One column generates a heavy ion beam (e.g., gallium or xenon ions) to process the sample S, while the other column generates an electron beam or light ion beam to obtain a microscopic image of the sample S. However, for dual-beam FIB systems, and even for FIB systems using three optical columns, the need to use two or more separately configured optical columns for sample processing and microscopic imaging results in high equipment costs, complex equipment structures, and cumbersome operation.

[0003] To address the aforementioned issues, while single optical devices exist that integrate the generation of heavy ion beams for processing and electron beams for imaging, their designs are often hampered by the complexity of mechanical switching tools or the instability of the electron emitter. Furthermore, because these single optical devices use liquid metal as the emitting material in their focused ion and electron beam systems, the liquid metal flows to the emitter tip to emit the ion beam, and after cooling, forms the metal tip substrate for emitting the electron beam. The liquid metal diminishes after heating and emission. Although the system continuously replenishes liquid metal to the emitter tip, the inherent instability of the liquid's shape means that the position and size of the liquid metal at the emitter tip cannot be fixed after each heating and cooling cycle.

[0004] Therefore, how to provide an ion microscope and focused ion beam system with a single optical device to solve the above problems has become an urgent research topic. Summary of the Invention

[0005] In view of the above problems, the present invention discloses an ion microscope and a focused ion beam system with a single optical device, comprising a vacuum chamber, an emitter, a gas pressure control device, an optical device, a voltage control module, and a signal control module. The vacuum chamber has an internal space. The emitter, the optical device, and the sample are disposed within the internal space of the vacuum chamber. The gas pressure control device stores at least one gas and is connected to the chamber wall of the vacuum chamber. The voltage control module is electrically connected to the emitter and the optical device, generating a draw voltage to the emitter and a bias voltage to the optical device. The signal control module connects to the gas pressure control device and the voltage control module, generating a gas-introducing control signal to the gas pressure control device, causing the gas pressure control device to introduce at least one gas into the internal space of the vacuum chamber. The signal control module adjusts the output bias voltage of the voltage control module output to the optical device and adjusts the absorption voltage of the voltage control module output to the emitter, so that the emitter generates a heavy ion beam for processing the sample and a light ion beam for imaging the sample through the at least one gas. The heavy ion beam for processing the sample is generated by a first gas in the at least one gas, and the light ion beam for imaging the sample is generated by a second gas in the at least one gas. The molecules of the first gas are larger than the molecules of the second gas, and the signal control module adjusts the absorption voltage according to the molecular types of the first gas and the second gas.

[0006] As described above, when the signal control module generates a gas introduction control signal to the gas pressure control device, the gas pressure control device introduces a first gas into the internal space of the vacuum chamber. The signal control module also generates a gas absorption voltage to the voltage control module, causing the emitter to emit an ion beam from the gas. The signal control module adjusts the output bias voltage of the voltage control module to the optical device, allowing the focusing lens module to adjust the spot size formed by the ion beam on the sample surface. The scanning deflection module controls the movement of the ion beam on the sample surface, processing and scanning the sample. The signal detector detects the signal generated by the interaction between the ion beam and the sample and transmits it back to the signal control module for image formation of the sample. Next, the signal control module generates a gas introduction control signal to the gas pressure control device, causing the gas pressure control device to introduce a second gas into the internal space of the vacuum chamber. The signal control module also generates a gas absorption voltage to the voltage control module, causing the emitter to emit an ion beam from the gas. The signal control module adjusts the output bias voltage of the optical device from the voltage control module. The focusing lens module adjusts the size of the spot formed by the ion beam on the sample surface. The scanning deflection module controls the ion beam to scan the sample surface. The signal detector detects the signal generated by the interaction between the ion beam and the sample, and sends it back to the signal control module for sample imaging. When the signal control module closes the gas regulating valve, preventing gas from entering the vacuum chamber, and waits for the pressure in the vacuum chamber to return to an ultra-high vacuum state, the signal control module generates an electron-drawing negative bias voltage to the voltage control module, causing the emitter to emit an electron beam. The signal control module adjusts the output bias voltage of the optical device from the voltage control module. The focusing lens module adjusts the size of the spot formed by the electron beam on the sample surface. The scanning deflection module controls the electron beam to scan the sample surface. The signal detector detects the signal generated by the interaction between the electron beam and the sample, and sends it back to the signal control module for sample imaging.

[0007] As described above, when the signal control module generates a gas control signal to the gas pressure control device, multiple gases can be introduced simultaneously. Based on the different ionization energies of various molecules, the desired ion beam can be selected. Alternatively, a mass separator can be added to the optical device to select the appropriate ion beam. Or, after completing a specified task with a single gas, the gas regulating valve can be closed, preventing further gas introduction into the vacuum chamber. Once the pressure around the emitter returns to an ultra-high vacuum state, another gas can be introduced for the corresponding task. In conclusion, the ion microscope and focused ion beam system of this invention, through the design of a single optical device, adjustment of the gas type within the vacuum chamber, and application of different ionization voltages, can generate multiple charged particle beams for various applications such as multifunctional processing, high-precision processing, high-resolution imaging, and sample composition analysis, further realizing the flexible generation and application of different charged particle beams. Furthermore, the design of a single optical device not only significantly reduces equipment costs and system complexity but also further enhances operational convenience. Attached Figure Description

[0008] Figure 1A This is a block diagram of the ion microscope and focused ion beam system with a single optical device according to the present invention.

[0009] Figure 1B A schematic diagram showing the emitter, optical device, and sample housed within a vacuum chamber;

[0010] Figure 1C This is a magnified schematic diagram of the emitter tip;

[0011] Figure 1D This is a schematic diagram showing that a vacuum chamber can be divided into an optical device vacuum chamber and a sample vacuum chamber.

[0012] Figure 1E A schematic diagram of the gas passage between the gas pressure control device and the vacuum chamber; and

[0013] Figure 2 This is a schematic diagram of a conventional dual-beam focused ion beam system. Detailed Implementation

[0014] Please see Figures 1A to 1C , Figure 1A This is a block diagram of the ion microscope and focused ion beam system with a single optical device according to the present invention. Figure 1B This is a schematic diagram showing the emitter, optical device, and sample housed within a vacuum chamber. Figure 1CThis is a magnified schematic diagram of the emitter tip. The ion microscope and focused ion beam system 1 with a single optical device includes a vacuum chamber 11, an emitter 12, a gas pressure control device 13, an optical device 14, a voltage control module 15, and a signal control module 16, wherein the voltage control module 15 and the signal control module 16 can be integrated into a voltage signal control device. The vacuum chamber 11 has an internal space, within which the emitter 12, the optical device 14, and the sample S are disposed. The gas pressure control device 13 stores at least one gas and is connected to the chamber wall 111 of the vacuum chamber 11. The voltage control module 15 is electrically connected to the emitter 12 and the optical device 14, generating a draw voltage to the emitter 12 and a bias voltage to the optical device 14. The signal control module 16 connects to the gas pressure control device 13 and the voltage control module 15, generating a gas introduction control signal to the gas pressure control device 13. This causes the gas pressure control device 13 to introduce at least one gas into the internal space of the vacuum chamber 11. The signal control module 16 adjusts the output bias voltage of the voltage control module 15 to the optical device 14 and the absorption voltage of the voltage control module 15 to the emitter 12. This allows the emitter 12 to generate a heavy ion beam for processing the sample S and a light ion beam for imaging the sample S through the at least one gas. The heavy ion beam for processing the sample S is generated by a first gas among the at least one gas, and the signal control module 16 adjusts the absorption voltage according to the molecular type of the first gas. The light ion beam for imaging the sample S is generated by a second gas among the at least one gas, and the signal control module 16 adjusts the absorption voltage according to the molecular type of the second gas, wherein the molecular weight of the first gas is greater than that of the second gas.

[0015] In this embodiment of the invention, the first gas is a gas with a molecular weight greater than 21, including xenon, krypton, oxygen, nitrogen and argon, and the second gas is a gas with a molecular weight less than 21, including hydrogen, neon and helium.

[0016] The ion microscope and focused ion beam system 1 with a single optical device also includes a signal detector 17 connected to the signal control module 16, which detects the signal generated by the interaction between the electron beam, the ion beam and the sample to generate an imaging signal and transmits the imaging signal back to the signal control module 16 to image the sample.

[0017] The optical device 14 includes a focusing lens module 141, a scanning deflection module 142, and a mass separator module 143, disposed on the ion beam and electron beam emission path between the emitter 12 and the sample S, for controlling the generated ion beam and electron beam. The focusing lens module 141 adjusts the size of the spot formed by the ion beam and electron beam on the sample. When the system generates a heavy ion beam for sample processing, the scanning deflection module 142 controls the movement and scanning of the ion beam on the sample surface. When the system generates a light ion beam and electron beam for sample imaging, the scanning deflection module 142 controls the movement and scanning of the ion beam and electron beam on the sample surface. When the signal control module generates a gas introduction control signal to the gas pressure control device 13, multiple gases, including a first gas and a second gas, can be introduced simultaneously. Based on the different ion energies of different molecules, an appropriate absorption voltage is applied to select the desired ion beam; or based on the different mass-to-charge ratios of different ions, the mass separator module 143 selects the desired ion beam. Alternatively, after completing a designated task with a single gas, the gas regulating valve 132 can be closed to prevent further gas introduction into the vacuum chamber 11. The vacuum pump 133 can then extract the gas from the vacuum chamber 11 before introducing another gas to perform the corresponding task. The mass screening module 143 allows ions with a specific charge-to-mass ratio to pass through without being deflected, while ions with different charge-to-mass ratios are deflected and blocked, thus allowing for further screening of the desired ions.

[0018] The gas pressure control device 13 includes a gas container 131, a gas regulating valve 132, and a vacuum pump 133. The vacuum pump 133 and the gas regulating valve 132 are respectively connected to the cavity wall 111 of the vacuum chamber 11 and the signal control module 16. The device regulates the introduction of gas into the vacuum chamber 11 according to the gas introduction control signal generated by the signal control module 16, and stops the introduction of gas into the vacuum chamber 11 according to the gas extraction control signal generated by the signal control module 16. The gas extraction control signal generated by the signal control module 16 is transmitted to the vacuum pump 133 to extract gas from the vacuum chamber 11. It should be noted that in the embodiments of the present invention, the order in which the heavy ion beam, light ion beam, and electron beam are generated is not limited, but can be generated according to the user's needs. For example, when a user wants to process and image sample S, the first gas and the second gas can be introduced sequentially or simultaneously, and heavy ion beams and light ion beams can be generated according to the different ionization energies of different molecules. Alternatively, a mass filter (i.e., a mass filter module 143) can be added to the optical device 14 to select the desired ion beam by filtering ions with different charge-to-mass ratios. Or, after introducing the processing gas, all the gas in the vacuum chamber 11 can be evacuated by the vacuum pump 133 before generating the electron beam for imaging.

[0019] In embodiments of the present invention, the vacuum chamber 11 can generate an ion beam by introducing a single gas, or by introducing a mixture of multiple gases into the vacuum chamber 11 to generate different ion beams, and generate an electron beam after all the gases in the vacuum chamber 11 are removed. Furthermore, the signal control module 16 generates a first gas introduction control signal, causing the gas pressure control device 13 to introduce the first gas into the internal space of the vacuum chamber 11, and causing the voltage control module 15 to apply a corresponding absorption voltage to the emitter 12 according to the ionization energy of the introduced first gas, further generating an ionizing electric field that can ionize gas ions, ionizing the gas adsorbed on the tip surface of the emitter 12 to generate a first gas ion beam. This ionizing electric field further attracts the gas adsorbed on the needle handle of the emitter 12 to the tip surface. Taking xenon as an example, when xenon is introduced into the internal space of the vacuum chamber 11, a positive absorption voltage (i.e., ionization voltage) is applied to the emitter 12 through the voltage control module 15. When the applied electric field reaches the ionization energy that can cause the xenon adsorbed on the tip surface of the emitter 12 to detach, a xenon ion beam is generated. This ionization electric field will further attract the xenon adsorbed on the emitter 12 to the tip surface of the emitter 12 to continuously generate a xenon ion beam.

[0020] When the signal control module 16 generates a gas extraction control signal, it closes the gas regulating valve 132, preventing the first gas from being introduced into the vacuum chamber 11. After the vacuum pump 133 extracts the first gas from the vacuum chamber 11, the signal control module 16 further generates a second gas introduction control signal to the voltage control module 15 and the gas pressure control device 13. This causes the gas pressure control device 13 to introduce the second gas into the internal space of the vacuum chamber 11, and the voltage control module 15 to apply a corresponding ionization voltage to the emitter 12 according to the ionization energy of the second gas, thereby generating a second gas ion beam.

[0021] When the signal control module 16 generates a gas extraction control signal, it closes the gas regulating valve 132 to prevent gas from being introduced into the vacuum chamber 11. After the vacuum pump 133 extracts the gas from the vacuum chamber 11 and the pressure around the emitter 12 returns to the ultra-high vacuum state, the signal control module 16 generates an electron absorption negative bias voltage to the voltage control module 15, causing the emitter 12 to emit an electron beam.

[0022] The ion beams generated in the various embodiments of the present invention can provide different functions depending on the weight of their corresponding gases, with the weight of the gases being distinguished by their molecular weight. Taking xenon and helium as examples, xenon is a heavy ion gas, while helium is a light ion gas. Therefore, a xenon ion beam formed using xenon can be used for processing sample S, while a helium ion beam formed using helium causes less damage to the structure of sample S and is therefore suitable for high-resolution scanning imaging of sample S.

[0023] Furthermore, when two or more mixed gases are introduced into the vacuum chamber 11 simultaneously, the applied ionization voltage can be adjusted according to the different ionization energies of the molecules to select the desired ion beam. To avoid interference caused by the ionization energies of different molecules being too similar, a mass filter can be added to the optical device to select the desired ion beam, so as to flexibly apply the ion beams generated by various gases to different operating environments.

[0024] Furthermore, the introduced gases can be categorized based on their ionization energy, molecular size, and activity to be used for sample processing, sample imaging, and mass spectrometry analysis. That is, by mixing different gases within the vacuum chamber 11 of a single optical structure and adjusting the applied ionization voltage accordingly, a wide range of ion beams can be used for processing, focusing imaging with light ion beams and electron beams, and mass spectrometry analysis with ion beams. For example, when the voltage applied by the voltage control module 15 causes the emitter 12 tip to reach the ionization voltage of the first gas, the first gas will detach from the surface of the emitter 12 tip to generate a first gas ion beam. When the voltage applied by the voltage control module 15 causes the emitter 12 tip to reach the ionization voltage of the second gas, the second gas will detach from the surface of the emitter 12 tip to generate a second gas ion beam. In addition, the signal control module 16 further adjusts the absorption voltage output from the voltage control module 15 to the emitter 12, causing the emitter 12 to generate a third gas ion beam for mass spectrometry analysis of sample S. The third gas ion beam comprises either an active gas ion beam or an ion beam formed by a molecular cluster.

[0025] In this embodiment of the invention, the tip of the emitter 12 has a wrinkled structure. The material of the emitter includes one single metal such as tungsten, iridium, molybdenum, palladium, platinum, rhodium, and gold, or a composite metal such as tungsten, iridium, molybdenum, palladium, platinum, rhodium, and gold, or tungsten is used as the emitter material and one or more metals such as iridium, molybdenum, palladium, platinum, rhodium, or gold are plated on the surface of tungsten.

[0026] Please refer to the following: Figure 1D and Figure 1EIn one embodiment of the present invention, the vacuum cavity 11 includes an optical device vacuum cavity 11A for carrying the emitter 12 and the optical device 14, and a sample vacuum cavity 11B for carrying the sample S. The optical device vacuum cavity 11A has a first cavity wall 111A and a first internal space, and the sample vacuum cavity 11B has a second cavity wall 111B and a second internal space. The first cavity wall 111A and the second cavity wall 111B together constitute the cavity wall 111 of the entire vacuum cavity 11. Furthermore, the first internal space of the optical device vacuum cavity 11A and the second internal space of the sample vacuum cavity 11B together constitute the internal space of the entire vacuum cavity 11.

[0027] The optical device vacuum chamber 11A and the sample vacuum chamber 11B are interconnected. The optical device vacuum chamber 11A contains a gas valve 11C, which, when closed, separates the optical device vacuum chamber 11A and the sample vacuum chamber 11B. Furthermore, the first cavity wall 111A of the optical device vacuum chamber 11A and the second cavity wall 111B of the sample vacuum chamber 11B are also connected to a vacuum pump 133, allowing both chambers to be pumped simultaneously to maintain a vacuum pressure. The gas container 131 is connected to the first cavity wall 111A of the optical device vacuum chamber 11A via a gas regulating valve 132, thereby supplying gas to the emitter 12 to facilitate the generation of a gas ion beam.

[0028] When gas valve 11C is closed, the sample vacuum chamber 11B can block the gas supplied by gas container 131 and continuously improve the vacuum quality by being evacuated by vacuum pump 133. Alternatively, when gas valve 11C is closed, the sample vacuum chamber 11B can be aerated to allow the user to replace the sample S placed in the sample vacuum chamber 11B, while at the same time, vacuum pump 133 continues to evacuate the optical device vacuum chamber 11A to maintain the vacuum quality within the optical device vacuum chamber 11A. Gas valve 11C can be a manual gas valve or an electrically controlled gas valve controlled by signal control module 16.

[0029] In summary, the electron beam and ion beam system of this invention, with its single optical structure, uses a robust and stable emitter structure to fix the emitter position, generating a stable charged particle beam. This ensures the stability and lifespan of both the ion and electron sources. Furthermore, by designing a single optical structure, adjusting the gas type within the vacuum chamber, and applying different ionization voltages, it can generate various charged particle beams for both ion and electron beams. This allows for applications in multifunctional processing, high-precision processing, high-resolution imaging, sample composition analysis, and other diverse needs, further enabling the flexible generation and application of different charged particle beams. Moreover, the single optical structure design significantly reduces equipment costs and system complexity, while also improving operational convenience.

[0030] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Although the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make some modifications or alterations to the above-disclosed technical content to create equivalent embodiments without departing from the scope of the technical solution of the present invention. Any simple modifications, equivalent changes and alterations made to the above embodiments based on the technical essence of the present invention without departing from the content of the technical solution of the present invention shall still fall within the scope of the technical solution of the present invention.

Claims

1. An ion microscope and a focused ion beam system with a single optical device, characterized in that, Include: A vacuum chamber having an internal space; An emitter is disposed within the internal space of the vacuum cavity; and A gas pressure control device, which stores at least one gas and is connected to a cavity wall of the vacuum cavity; An optical device is disposed between the emitter and a sample; A voltage control module, electrically connected to the emitter and the optical device, generates a draw voltage to the emitter and a bias voltage to the optical device; and A signal control module is connected to the gas pressure control device and the voltage control module. It generates a gas introduction control signal to the gas pressure control device, so that the gas pressure control device introduces at least one gas into the internal space of the vacuum chamber. The signal control module adjusts an output bias voltage output by the voltage control module to the optical device and adjusts the absorption voltage output by the voltage control module to the emitter, so that the emitter generates a heavy ion beam for processing or analyzing the sample and a light ion beam for imaging the sample through the at least one gas. The heavy ion beam used for processing or analyzing the sample is generated by a first gas among the at least one gases, and the light ion beam used for imaging the sample is generated by a second gas among the at least one gases. The molecular weight of the first gas is greater than that of the second gas, and the signal control module adjusts the absorption voltage according to the type of molecule.

2. The ion microscope and focused ion beam system with a single optical device as described in claim 1, characterized in that, The first gas contains xenon, krypton, oxygen, nitrogen, and argon, and the second gas contains hydrogen, neon, and helium.

3. The ion microscope and focused ion beam system with a single optical device as described in claim 1, characterized in that, The first gas has a molecular weight greater than 21, and the second gas has a molecular weight less than 21.

4. The ion microscope and focused ion beam system with a single optical device as described in claim 1, characterized in that, The at least one gas is a mixture of the first gas and the second gas, and the signal control module adjusts the absorption voltage output by the voltage control module to the emitter according to the molecular types of the first gas and the second gas.

5. The ion microscope and focused ion beam system with a single optical device as described in claim 1, characterized in that, The signal control module generates the gas introduction control signal to the gas pressure control device, causing the gas pressure control device to introduce the first gas into the internal space of the vacuum chamber. Then, the signal control module further generates a gas extraction control signal to the gas pressure control device, causing the first gas to be extracted. After that, the signal control module generates the gas introduction control signal to the gas pressure control device, causing the gas pressure control device to introduce the second gas into the internal space of the vacuum chamber.

6. The ion microscope and focused ion beam system with a single optical device as described in claim 1, characterized in that, The optical device includes a mass filter to filter a gas ion beam containing the heavy ion beam and the light ion beam.

7. The ion microscope and focused ion beam system with a single optical device as described in claim 1, characterized in that, The signal control module further generates a gas extraction control signal to the gas pressure control device, so that at least one gas is extracted, and the signal control module adjusts the absorption voltage output by the voltage control module to the emitter to a negative bias voltage, so that the emitter generates an electron beam for imaging the sample.

8. The ion microscope and focused ion beam system with a single optical device as described in claim 1, characterized in that, One tip of the emitter has a wrinkled structure.

9. The ion microscope and focused ion beam system with a single optical device as described in claim 1, characterized in that, The emitter is made of one of the following metals: tungsten, iridium, molybdenum, palladium, platinum, rhodium, or gold, or more than one of the following metals: tungsten, iridium, molybdenum, palladium, platinum, rhodium, or gold.

10. The ion microscope and focused ion beam system with a single optical device as described in claim 1, characterized in that, The optical device includes: A focusing lens module is used to adjust the size of the spot formed by the ion beam on the sample. A scanning deflection module controls the movement and scanning of the ion beam on the sample surface.

11. The ion microscope and focused ion beam system with a single optical device as described in claim 1, further comprising a signal detector connected to the signal control module, for detecting the signal generated by the interaction between the ion beam and the sample, so as to generate an imaging signal to the signal control module.

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