Ion source with pressure measurement device

Abstract

The invention relates, inter alia, to an ion source (10) for generating ions (16) or ion beams (16a), having an ion generation chamber (11) in which the ions (16) are generated. To monitor the ion source (10) and in particular ensure its safety, according to the invention the ion source (10) has a pressure measurement device (30) allocated to the ion generation chamber (11), wherein the pressure measurement device (30) has a first pressure measurement unit (31), which in particular is designed in the form of a gas-friction manometer or which in particular has a gas-friction manometer. The invention also relates to a method for handling such an ion source (10).

Description

[0001] ion source

[0002] Description

[0003] The present invention primarily relates to an ion source. Furthermore, the invention relates to an ion generation device comprising an ion source, as well as a method for handling an ion source, in particular for generating ions in an ion source.

[0004] An ion source, also called an ion gun or, depending on its design, a plasmatron, is used to generate ions and, depending on its configuration, also ion beams. The ions are often generated in an ion generation chamber. In the ion generation chamber, the ions are first generated and, if necessary, a more or less directed movement of ions is generated. This often occurs in a vacuum. Ion sources themselves are known in various forms from the state of the art and are familiar to experts, so they need not be discussed in detail here.Ion sources are particularly components of ion generation devices, or they are components of systems in which ions are used in the processing of workpieces. Ion sources can be used in a wide variety of areas, for example in nuclear fusion, in mass spectrometers, in implantation systems, in ion microprobes, in rocket propulsion and the like.

[0005] DE 102021 129731 A1 by the applicant discloses an ion generation device used in an implantation system. The implantation system has an ion generation device, which in turn has an ion source as one component. The ions are generated by means of the ion source. An ion beam is generated in a device for generating an ion beam. This device has a device for extracting the ions using an electrostatic field, and / or a device for separating the ions by mass in a mass spectrometer, and / or a device for accelerating the ions. Furthermore, the ion generation device has a device for deflecting the ion beam in the electric field, by means of which the ion beam is directed onto a workpiece to be processed. Finally, the ion generation device has means for implanting the ions into the workpiece to be processed.The workpiece is located in a process chamber of the implantation system, and the implantation process also takes place within the process chamber of the implantation system. The ion beams generated in the ion source and directed in the ion generation device impinge on the workpiece to be processed. A pressure measuring device in the form of a gas friction manometer is assigned to the process chamber of the implantation system. The pressure measuring device measures the pressure, particularly a vacuum, in the process chamber of the implantation system during the implantation process. The generated pressure measurement signal is used to determine a correction factor that also takes into account ions neutralized during the process.

[0006] The object of the present invention is to improve the performance of such an ion source.

[0007] This object is achieved according to the invention by the ion source having the features according to independent patent claim 1, which forms the first aspect of the invention, by the ion generating device having the features according to independent patent claim 10, which forms the second aspect of the invention, and by the method having the features according to independent patent claim 11, which forms the third aspect of the invention.

[0008] Further features and details of the invention emerge from the dependent claims, the description, and the drawings. Features and details described in connection with one aspect of the invention also apply in full to the other aspects of the invention, and vice versa, so that with regard to the disclosure of one aspect of the invention, reference is always made in full to the disclosure of the other two aspects of the invention.

[0009] The present invention is not limited to specific areas of application for ion sources. Likewise, the invention is not limited to specific types of ion sources.

[0010] The basic idea of ​​the present invention is that a pressure measuring device is now directly associated with the ion source. This determines the pressure of the ion source, in particular at or in the ion source, preferably individually for the ion source. In this way, the performance of the ion source is further improved. This can be achieved in various ways. For example, the ion source can be specifically controlled and / or monitored based on the pressure determined by the pressure measuring device. In particular, important parameters of the ion source, in particular control parameters, can also be determined and / or controlled and / or monitored using the pressure measuring device. Alternatively or additionally, the pressure measuring device can also be used to monitor the safety of the ion source.

[0011] According to the present invention, at least one gas friction manometer is used for pressure and process monitoring in the area of ​​the ion source. However, the invention is not limited to this configuration.

[0012] Monitoring is preferably carried out independently of the application area and method in which and for which the ion source is used. Monitoring is carried out directly, i.e., immediately, at the ion source. This allows for early intervention, if necessary.

[0013] According to the first aspect of the invention, an ion source is provided having the features of independent claim 1.

[0014] The ion source serves to generate ions or ion beams. This means that the ion source is provided so that at least ions, or depending on the design, ion beams, are or can be generated. An ion source is, in particular, a device with which ions are generated. Ions are electrically charged atoms. With the ion source according to the invention, both positive and negative, as well as singly and multiply charged ions of a wide variety of chemical elements, can be generated. In a simple embodiment, the ion source serves to generate ions. In another embodiment, the ion source serves to generate ion beams in addition to generating the ions themselves. In this case, the ion source generates a more or less directed movement of the ions.

[0015] The ion source consists of at least one ion generation chamber in which the ions are generated. A chamber is, in particular, a preferably small space that is largely or completely enclosed, in which the ions are generated. In one embodiment, the ion generation chamber has a chamber wall that defines a chamber interior. If necessary, one or more connections for additional components, inlets, and outlets can be located in the chamber wall, as described in more detail below using exemplary examples. The ion generation chamber can, for example, be designed as a cylindrical chamber, although the invention is, of course, not limited to this specific configuration.

[0016] In a further embodiment, the ion source can also comprise additional components located on or in the ion generation chamber, which are designed and provided to generate a, in particular, directed, ion beam. These components can be of different types depending on the nature of the ion source.

[0017] Furthermore, according to the invention, the ion source has a pressure measuring device assigned to the ion generation chamber, wherein the pressure measuring device has at least one first pressure measuring device. According to the invention, a pressure measuring device is thus directly assigned to the ion generation chamber. This means that the pressure measuring device is provided in such a way that it cooperates with the ion generation chamber, in particular in order to be able to determine the pressure in the ion generation chamber. A pressure measuring device is, in particular, a device by means of which a pressure, in particular the pressure conditions, are determined, for example, measured or determined. In one embodiment, the pressure measuring device is connected to the ion generation chamber, preferably in such a way that the pressure at or in the ion generation chamber is or can be measured with the pressure measuring device.

[0018] The pressure measuring device and the first pressure measuring device can be designed in different ways. Some exemplary embodiments will be explained in the further course of the description.

[0019] In one embodiment, the pressure measuring device is designed in the form of a physical entity. An entity is to be understood as a unit. A physical entity represents a physical unit. All components therefore represent internal components with regard to the pressure measuring device. This means in particular that all components are arranged or formed within a housing. In a second embodiment, the pressure measuring device is designed partly in the form of a physical entity and partly in the form of a functional entity. A functional entity is characterized in particular in that the components are spatially separated from one another and the unit results from the functional interaction of the individual components. In this case, only a subgroup of the components are internal components within the meaning of the first embodiment.At least one component of the pressure measuring device is designed as an external component.

[0020] In a third embodiment, the pressure measuring device is designed as a purely functional entity. This means that all components are designed as independent, spatially separated components. However, the individual components are functionally connected to one another in a suitable manner to implement the pressure measuring device.

[0021] According to the invention, the pressure measuring device has a first pressure measuring device which is designed in a special way.

[0022] In principle, the invention is not limited to specific types of first pressure measuring devices. A number of exemplary embodiments are described in the course of the description. In one embodiment, the first pressure measuring device is designed as a pressure measuring device for highly accurate and / or long-term stable pressure measurement. In a preferred embodiment, the first pressure measuring device is designed in the form of a gas friction manometer, which is also referred to synonymously as SRG in the description, or it comprises a gas friction manometer.

[0023] A gas friction manometer can be used to very accurately measure the pressure in the ion generation chamber, which is often a negative pressure, especially a vacuum. The resulting pressure measurement signal can also be used to determine a correction factor.

[0024] The gas friction manometer (SFG) is non-ionizing, less dependent on gas types, less sensitive to coatings, and, above all, very stable over time compared to many other measuring devices, such as ionization gauges or Piranis. This is primarily due to the fact that it only determines the decrease in the rotational frequency of a sphere rotating contactlessly in a vacuum. This is a mathematical process, without any electrical and / or mechanically loaded components in the measuring area.

[0025] The gas friction manometer is characterized by high precision and absolute accuracy and / or long-term stability. Furthermore, it should not affect the vacuum, be resistant to the media used, and be as resistant as possible to contamination.

[0026] According to one embodiment, the gas friction manometer has a rotating sphere. Such a gas friction manometer basically works as follows: A sphere is frictionlessly mounted in a magnetic field. An external rotating field drives the sphere, causing it to rotate. The drive is then switched off. The molecules in the residual gas decelerate the sphere. Sensing coils measure the decrease in rotational speed and determine the particle density of the gas. The deceleration rate can be measured directly as a measure of density or pressure. With this method, only the global properties of the sphere are included in the measurement and are assigned a factor (calibration factor); the rest of the arrangement is not variable or subject to error. The pressure measurements provided by the gas friction manometer are preferably provided in the form of electrical signals.

[0027] The gas friction manometer is, or rather enables, a measuring method that is currently characterized by its high accuracy (1% of the measured value) and a wide (> 6 decades) measuring range extending into the high vacuum range (HV) (>10 to 1x10' 7hPa), but in principle operates in all pressure ranges. The pressure measuring device has a very simple design, using a rotating sphere as the sensor. It operates without contact, without feedthroughs into the vacuum or mechanically stressed components. All information and interactions are transmitted via magnetic and electromagnetic forces into the vacuum. The gas friction manometer therefore has no electrically or mechanically stressed components and achieves correspondingly high long-term stability (drift < 1% / year). It is also robust and corrosion-resistant, for example, when made of all-metal. Since the measurement signal is based on the change in the rotation frequency of a spherical body and not on changes in distance or the ionization of gases, the process is far less influenced by temperature, aging, or coating effects.Due to its accuracy in high vacuum and long-term stability, the gas friction manometer is used as a transfer standard in many calibration laboratories.

[0028] According to another embodiment, the first pressure measuring device is designed as a so-called 10N gauge measuring tube. This will be explained in more detail later in the description. The invention is not limited to the examples mentioned.

[0029] In principle, it is sufficient if the pressure measuring device has a single first pressure measuring device. According to another embodiment, the pressure measuring device has two or more pressure measuring devices. In one embodiment, for example, at least one pressure measuring device is designed as a first pressure measuring device in the form of a gas friction manometer, or has a gas friction manometer. However, the pressure measuring device can also have two or more first pressure measuring devices. Or the pressure measuring device has at least one first pressure measuring device and at least one further pressure measuring device, which is then preferably designed in a different way and is referred to as a second pressure measuring device for differentiation. The invention is not limited to specific types of second pressure measuring devices. Some exemplary embodiments are described in the further course of the description.The first pressure measuring device can also be called a measuring tube.

[0030] Some embodiments of different pressure measuring devices are described below.

[0031] If measurements are typically not taken down to atmosphere, but rather in a vacuum, for example, at least a second pressure measuring device or a second measuring tube, for example in the form of a combination transducer, is also provided. Transducers are in particular converters or transformers that convert one form of energy into another. In one embodiment, such a combination transducer can, for example, comprise a Pirani component and a piezo component. A Pirani component is in particular a specific measuring device for pressure measurement in the rough and fine vacuum range and is generally familiar to those skilled in the art. If the pressure measuring device only has one pressure measuring device, this pressure measuring device is in one embodiment in the form of a combination transducer.In one embodiment, such a combination transducer can consist of a first pressure measuring device, in particular in the form of a gas friction manometer, for example with a measuring range of 10-8 mbar to 10-3 mbar, and a further pressure measuring device, in particular with a Pirani component, possibly combined with a piezo component, for example with a measuring range of 10-3 mbar to 1000 mbar.

[0032] In order to cover the entire pressure range with the pressure measuring device, according to one embodiment, a first pressure measuring device in the form of an ION gauge measuring tube is used, for example, which has a measuring range from 10-8 mbar to 10-3 mbar. An ION gauge measuring tube, also referred to as an ionization vacuum gauge, is a known pressure measuring device for determining pressure in the high and ultra-high vacuum range. A further, second pressure measuring device or measuring tube, which has a measuring range from 10-3 mbar to 00 mbar, for example, can be provided in the form of a combination transducer. Such a combination transducer combines two measuring principles, for example "Pirani" and "Piezo", which are installed in one measuring tube. In another embodiment, this second pressure measuring device is provided as a simple transducer with only one measuring principle.

[0033] In one embodiment, a gas friction manometer is used instead of the ION Gauge component. In this case, the first pressure measuring device and the second pressure measuring device are provided, for example, as separate measuring tubes.

[0034] According to another embodiment, the pressure measuring device is provided in the form of only a single pressure measuring device. In this case, the pressure measuring device can be provided as a combination transducer that covers the entire range and, for example, combines multiple measuring principles. For example, such a combination transducer can comprise an ION gauge component and, for example, a Pirani component and / or a piezo component. In one embodiment, a gas friction manometer is used instead of the ION gauge component.

[0035] In one embodiment, a control device is assigned to the ion source. A control device is, in particular, the entirety of all components that influence the ion source. The control device can be embodied in the form of hardware components or software components, or as a combination thereof. In particular, the control device has a processor device in which at least parts of the method according to the third aspect of the invention run. The control device preferably has interfaces to various components of the ion source. For example, certain values ​​or parameters of the ion source are recorded by means of the components, transmitted to the control device, and evaluated there. Individual components of the ion source can then be controlled accordingly via the control device.This will be explained in more detail below using exemplary examples, particularly in connection with the method according to the third aspect of the invention. Depending on the configuration, the control device is at least partially a component of the ion source. Alternatively, the control device is a component external to the ion source, which is then at least temporarily connected to the ion source via the interfaces, for example, wirelessly or wired, and communicates with it.

[0036] In one embodiment, the first pressure measuring device is connected to the ion generation chamber, for example, via a suitable connection. In another embodiment, the first pressure measuring device is arranged in the ion generation chamber.

[0037] In one embodiment, the ion generation chamber is designed as an ion generation chamber with negative pressure, in particular as a vacuum-tight ion generation chamber. For this purpose, in one embodiment, the ion generation chamber is connected to an evacuation device, for example, a vacuum pump. In one embodiment, the evacuation device is connected to the control device via a suitable interface.

[0038] In one embodiment, the first pressure measuring device is oriented horizontally. This means that the first pressure measuring device has a vertical orientation with respect to the ion generation chamber. If such an arrangement is not directly possible, a corresponding angled connection, such as a corresponding angled pipe or the like, can be provided between the first pressure measuring device and the ion generation chamber.

[0039] The present invention is not limited to specific types of ion sources. The ionization of molecules can occur, for example, through impact ionization, chemical ionization, thermal ionization, or field ionization. In an electric field, for example, the ions can be accelerated after generation and focused and deflected by electric or magnetic lenses. The ion source according to the invention is not limited to specific types of ionization. The only requirement is that the ionization of the molecules takes place in an environment, in particular in a chamber, in which a pressure can be measured.

[0040] In one type of ion source, the ionization of the molecules to be ionized occurs within the ion generation chamber under negative pressure or vacuum. In this case, the ion generation chamber is preferably connected to an evacuation device, which creates a negative pressure / vacuum in the ion generation chamber.

[0041] In one embodiment, the ion source is designed as an ion source for electron ionization. This type of ionization is a very widespread ionization method. Electrodes from a cathode, which is in particular a so-called filament, such as a filament, are accelerated by an electric field. Electrons are emitted from the surface of the cathode. These electrons are accelerated in an electric field to an anode. These electrons are sent through molecules to be ionized, for example, a corresponding gas, by moving through the ion generation chamber. For this purpose, an accelerating voltage is applied. If the electrons collide with molecules to be ionized, they are ionized. These molecules to be ionized, for example in the form of a gas stream, are introduced into the ion generation chamber.When molecules and electrons approach each other and interact, ionization can occur. The ion generation chamber is a vacuum-tight component. Electron ionization occurs particularly under low pressure, such as a vacuum. The pressures prevailing in the ion generation chamber are measured by the first pressure measuring device, the gas friction manometer.

[0042] In one embodiment, a cathode, particularly in the form of a filament, and an anode are arranged in the ion generation chamber. In one embodiment, the cathode and / or the anode are connected to the control device via a suitable interface. Preferably, the first pressure measuring device is provided at a spatial distance from the cathode, or at a distance from the cathode. For example, the ion source is designed as a cold cathode source or as a hot cathode source.

[0043] In principle, however, the first pressure measuring device can be arranged at any location on or in the ion generation chamber, for example depending on where a vacuum connection is located.

[0044] In one embodiment, the ion generation chamber is connected to a supply for molecules to be ionized, in particular to a gas supply. The supply supplies the ion generation chamber, i.e., the chamber interior, with molecules to be ionized, in particular in the form of a gas stream.

[0045] In one embodiment, the supply cooperates with a mass flow controller. In one embodiment, the mass flow controller is located in the supply, or it provides a transition between the supply and the ion generation chamber. The mass flow controller is, in particular, a component with which the mass flow of the molecules to be ionized entering the ion generation chamber can be regulated, in particular to a setpoint. For this purpose, in one embodiment, the mass flow controller is connected to the control device via an interface. In one embodiment, the mass flow controller comprises a controller and a valve interacting therewith. The use of such a mass flow controller in conjunction with the ion source is illustrated below using an example.Pressure values ​​are measured with the first pressure measuring device in the ion generation chamber and compared with target values. The comparison takes place primarily in the control device. To ensure that the target values ​​and the actually measured values ​​match, the mass flow control device is actuated accordingly as needed, for example, by the valve opening or reducing the size of the inlet opening of the supply to the ion generation chamber accordingly. This is also described further below in connection with the method according to the invention, so that at this point, reference is also made in full to the corresponding explanations below.

[0046] In one embodiment, the ion source is additionally characterized by an extraction device, which serves in particular for extracting the ions, for example from a plasma, and for beam shaping. Accordingly, such an extraction device is provided in particular for shaping an ion beam and / or for aligning an ion beam and / or for extracting ions from the supplied molecules to be ionized. In one embodiment, the extraction device is a component of the ion source. In this case, the ion source has both the ion generation chamber and an extraction device. In another embodiment, such an extraction device is assigned to the ion source, in particular downstream. This means that the ion source cooperates with the extraction device, with the extraction device being downstream of the ion source.In this case, only the ions are generated in the ion source, and the ions are then formed into an ion beam in the extraction device.

[0047] In one embodiment, the ion generation chamber has an outlet for the generated ions and / or for the generated ion beam.

[0048] In one embodiment, a pre-acceleration device is provided in the ion generation chamber. The pre-acceleration device pre-accelerates the generated ions in the icon generation chamber. In one embodiment, the pre-acceleration device is connected to the control device via a suitable interface.

[0049] In one embodiment, a lens device is provided in the ion generation chamber. The lens device, for example in the form of a focusing lens device, such as an electrostatic lens device, focuses the ion beam. If the lens device is variable, in one embodiment it is connected to the control device via a suitable interface.

[0050] In the above-described embodiments, the pre-acceleration device and / or the focusing device are each part of the ion source. According to another embodiment, the pre-acceleration device and / or the focusing device are not part of the ion source. In this case, they are arranged downstream of the ion source. The pressure measuring device, in particular the first pressure measuring device, can assume or fulfill various tasks and functions in conjunction with the ion source. Some examples are listed below, which can be implemented either individually or in any combination.For example, the pressure measuring device, in particular the first pressure measuring device, is designed or provided for controlling and / or monitoring the ion source, in particular for determining and / or regulating and / or monitoring important parameters of the ion source, in particular control parameters, in particular for controlling and / or monitoring the mass flow control device, and / or for measuring the pressure within the ion generation chamber, and / or for determining the cleanliness of the components within the ion generation chamber, and / or for determining the tightness of the ion source.

[0051] For example, the pressure measuring device, in particular the first pressure measuring device, monitors the mass flow control device. This means it regulates the gas inlet into the ion generation chamber and thus sets the pressure. Alternatively, the pressure measuring device measures the pressure in the ion generation chamber itself, i.e., the quality of the vacuum. Alternatively, the pressure measuring device measures the cleanliness of the ion source components in the vacuum. For example, the ion source is changed approximately every two weeks due to its reaction with corrosive gases. Despite careful storage, a new ion source is coated with "dirt," which initially diffuses into the ion generation chamber and thus causes a higher vacuum pressure. Alternatively, the pressure measuring device measures the tightness of the ion source.Maintenance and the associated ventilation can lead to leaks upon restart, for example, if seals are not properly secured or if components are damaged. In particular, the pressure measuring device according to the invention, in particular the first pressure measuring device, serves as a general safety device.

[0052] According to the second aspect of the invention, an ion generating device is provided which has the features of independent claim 11.

[0053] The ion generation device initially comprises an ion source with an ion generation chamber for generating the ions, and a pressure measuring device associated with the ion generation chamber. The pressure measuring device comprises a first pressure measuring device, which is designed in particular in the form of a gas friction manometer, or which in particular comprises a gas friction manometer. In particular, the ion generation device comprises an ion source according to the first aspect of the invention. For this reason, to avoid repetition, reference is also made in full to the statements relating to the first aspect of the invention.

[0054] Furthermore, the ion generation device comprises an extraction device provided for shaping an ion beam and / or for aligning an ion beam and / or for extracting ions from the supplied molecules to be ionized. In one embodiment, the extraction device is at least partially a component of the ion source or is connected to the ion source. In this regard, reference is also made in full to the corresponding statements in connection with the ion source according to the invention above.

[0055] The ion generation device further comprises a device for accelerating the ions generated in the ion source. Said acceleration device accelerates the ions to their final energy and is, in particular, a separate, independent component from the pre-acceleration device described above, which pre-accelerates the ions generated in the ion generation chamber of the ion source. Depending on the design, however, only a single acceleration device can be provided, which performs both the pre-acceleration and the final acceleration of the ions.

[0056] In addition, the ion generation device can also comprise a device for separating the ions according to mass in a mass separator, and / or a device for deflecting the ion beam in the electric field, by means of which the ion beam is directed onto the workpiece to be processed, in particular onto the base material of the workpiece.

[0057] All of the aforementioned components of the ion generation device can also be part of the ion source, so that such an ion source then assumes the function of an ion generation device. In another embodiment, the ion source is an independent functional and / or structural entity in which only the ions are generated. The other features of the ion generation device are then not part of the ion source, but are assigned to it. In one embodiment, the ion source according to the invention and / or the ion generation device according to the invention are used in conjunction with an ion implantation system. Ion implantation is a process for introducing foreign atoms in the form of ions into a base material. In this way, the material properties of the base material can be modified.Such an implantation method basically involves the following steps: First, ions are generated in an ion source, for example, in an ion source according to the first aspect of the invention. The ions are then extracted using an electrostatic field. The ions are then separated by mass in a mass separator. The ions are then accelerated and deflected using electric fields. These steps are performed, for example, in the ion generation device according to the invention or, with regard to extraction, optionally also in the ion source according to the invention. Finally, implantation into the base material takes place. Ion sources according to the first aspect of the invention can, however, be used in a wide variety of fields, for example, in nuclear fusion, in mass spectrometers, in implantation systems, in ion microprobes, in rocket propulsion, and the like.The invention is not limited to specific fields of application.

[0058] According to the third aspect of the invention, a method is provided which has the features of independent claim 12. The method serves to handle the ion source. That is, the method serves to determine how the ion source is used in a specific manner. In one embodiment, this use represents the generation of ions or an ion beam. However, in one embodiment, the use also represents the monitoring and / or control of the ion source. In one embodiment, the use represents a combination of the two previously described types of use.

[0059] In particular, the method serves for handling an ion source according to the first aspect of the invention. To avoid repetition, reference is therefore also made in full to the statements relating to the first aspect of the invention.

[0060] The ion source is provided in such a way that ions are generated from molecules to be ionized in an ion generation chamber of the ion source in an ion generation process. According to the invention, the method is characterized in that, before and / or during and / or after the ionization process, pressure values ​​at or in the ion generation chamber are recorded or determined via a pressure measuring device assigned to the ion generation chamber. The pressure measuring device has a first pressure measuring device, which is designed in particular in the form of a gas friction manometer, or which in particular has a gas friction manometer. In this way, pressure and process monitoring in the region of the ion source can be carried out using the pressure measuring device.

[0061] In one embodiment, the method is further characterized by the following steps: a) Molecules to be ionized, particularly in a gas stream, are fed into the ion generation chamber of the ion source via a feed; b) In the ionization process, ions are generated from the molecules to be ionized in the ion generation chamber. In this way, ions or an ion beam are also generated by the method.

[0062] In one embodiment, the method serves to carry out pressure and process monitoring in the region of the ion source by means of the pressure measuring device before and / or during and / or after the ionization process, and that, based on this, the parameters of the ionization process are adjusted such that the generation of the ions is carried out on the basis of the results determined during the monitoring.

[0063] In one embodiment, the ion source is released or the ionization process is started when the pressure measuring device, in particular the first pressure measuring device, measures that the pressure value, in particular the vacuum pressure in the ion generation chamber, falls below a certain predetermined pressure value.

[0064] In this case, the ion source, or rather the ionization process, is only enabled—for example, by activating the gas inlet, i.e., the mass flow controller, valves to specific vacuum pumps, possibly actuating vacuum shutters to the next process chamber, or similar—when the pressure measuring device, in particular the first pressure measuring device, detects that a certain vacuum pressure has been undershot. Otherwise, components could be damaged, the actual process could be jeopardized, or harmful gases could escape from the chambers, for example, in the event of a leak.

[0065] According to another embodiment, the ionization process can alternatively or additionally be started or carried out when the pressure measuring device is bypassed. A suitable switching device, which in one embodiment is connected to the control device via a suitable interface, can then be individually switched as needed, whether the pressure measuring device is / is switched on at the beginning of the ionization process and / or during the ionization process or is bypassed. Such a procedure is useful, for example, if there is a risk that the pressure measuring device could fail, particularly during the ionization process.

[0066] In one embodiment, the pressure measuring device, in particular the first pressure measuring device, is used to monitor and / or calibrate the mass flow control device provided for supplying the molecules to be ionized. This will be illustrated by an example:

[0067] With a first pressure measuring device, particularly in the form of a gas friction manometer due to its 100% linearity, it is possible to calibrate the mass flow controller device. In one embodiment, the standard cubic centimeters per minute (sccm) are plotted or displayed against the pressure in a graph. This preferably takes place in the control device described above. The unit "sccm" describes a defined flowing gas quantity, i.e., particle number or gas mass, per time period, i.e., a particle flow or mass flow, independent of pressure and temperature. If the curve is not linear, this means that the mass flow controller device is drifting, i.e., not functioning properly.

[0068] A processing plant typically runs various processes with different gas mixtures and gas quantities. For example, a process or a "recipe" can be composed of different gas quantities. This will be illustrated using an example in which such a process or "recipe" is composed of the different gas types H2, BF3, and Ar, for example: • a process: H2 (1sccm), BF3 (2sccm), and Argon (1sccm), and

[0069] • another process: PH3 (3sccm) and argon (1 sccm).

[0070] Occasionally, such a process is also adjusted, i.e., small changes to "sccm." This is reflected in the pressure and can be measured using the pressure measuring device, especially the first pressure measuring device, such as the gas friction manometer. This allows for monitoring whether the processes and components have adopted the changes. Many other processes with different gas mixtures and gas quantities are, of course, also possible.

[0071] A further advantage of the ion source and method according to the invention lies in the reduction of the process window. Since the solutions according to the invention, especially the values ​​determined therewith, are reproducible and do not drift, the permissible pressure window within which the ionization process may proceed can be reduced and optimized (example: process pressure 2E-5 mbar, limits with standard pressure gauges 5E-6 mbar / 4E-5 mbar -> limits with gas friction manometers 1.6E-5 mbar / 2.4E-5 mbar). This optimization allows the required gas quantity for optimal results to be precisely determined and ultimately the gas quantity can be reduced under certain circumstances, leading to cost savings.

[0072] In one embodiment, it is realized that the pressure measuring device, in particular the first pressure measuring device, controls and / or monitors the ion source, in particular determines and / or regulates and / or monitors important parameters of the ion source, in particular controls and / or monitors the mass flow control device, and / or measures the pressure within the ion generation chamber, and / or determines the cleanliness of the components within the ion generation chamber, and / or determines the tightness of the ion source.

[0073] Depending on the system and type, the standard gauge tubes used in ion generation typically fail within two to eight weeks. This results in unplanned downtimes, but at the very least, requires trained personnel to repair / replace the gauge tubes. These disadvantages can now be avoided with the solutions according to the invention. The invention will now be explained in more detail using exemplary embodiments with reference to the accompanying drawings. They show:

[0074] Figure 1 shows a schematic view of an ion source according to the present invention; and

[0075] Figure 2 shows a schematic view of a first pressure measuring device designed as a gas friction manometer, which interacts with the ion source.

[0076] Figure 1 shows an embodiment of an ion source 10 according to the invention. The ion source 10 has an ion generation chamber 11 having a chamber wall 11a, wherein the chamber wall 11a delimits a chamber interior 11b. The ion generation chamber 11 is connected via a connection 12 to a connection flange 34 of a pressure measuring device 30. This pressure measuring device 30, which will be described in more detail later with reference to Figure 2, has, for the sake of simplicity, only a first pressure measuring device 31 in the form of a gas friction manometer to illustrate the principle of the invention. The components of the first pressure measuring device 31 are located within a housing 33. The first pressure measuring device 31 is oriented vertically with respect to the ion generation chamber 11, which is represented by the arrow 32.

[0077] The ion generation chamber 11 is further connected to a supply 14 for molecules 15 to be ionized, which are fed into the ion generation chamber 1 in the form of a gas stream. The molecules 15 to be ionized are shown as small circles in Figure 1. To control the quantity of molecules 15 to be ionized, a mass flow controller 17 is arranged or formed in the supply 14.

[0078] To generate ions 16, which are shown as small squares in Figure 1, a cathode 13a, which has a filament, and an anode 13b are arranged in the ion generation chamber 11. A magnetic field can be applied via the provided magnets 29.

[0079] To generate an ion beam 16a, a pre-acceleration device 19 and a lens device 20 are also provided in the ion generation chamber 11. Depending on the configuration, the pre-acceleration device 19 and the lens device 20 are components of the ion source 10. Alternatively, they may be independent components compared to the ion source 10, which are then arranged downstream of the ion source 10. This is schematically represented by the dot-dash line within the ion generation bracket 11.

[0080] The generated ion beam 16a leaves the ion generation chamber 11 via an exit 18.

[0081] In the embodiment shown in Figure 1, the ion source 10 is designed as an ion source for electron ionization. Electrodes from the cathode 13a, which is in particular a so-called filament, such as a filament, are accelerated by an electric field. Electrons are emitted from the surface of the cathode 13a. These electrons are accelerated in an electric field to an anode. These electrons are sent through molecules 15 to be ionized, for example, a corresponding gas, by moving through the ion generation chamber 11. When the electrons hit molecules 15 to be ionized, they are ionized, i.e., converted into ions 16.

[0082] The ion generation chamber 11 is, in particular, a vacuum-tight component. Electron ionization occurs, in particular, in a vacuum. For this purpose, the ion generation chamber 11 is connected to a vacuum pump 22. The pressures prevailing in the ion generation chamber 11 are measured by the first pressure measuring device 31 in the form of a gas friction manometer.

[0083] Before and / or during and / or after the ionization process, pressure values ​​in the ion generation chamber 11 are recorded or determined via the pressure measuring device 30 assigned to the ion generation chamber 11, which has at least one first pressure measuring device 31, for example in the form of a gas friction manometer. In this way, pressure and process monitoring in the area of ​​the ion source 10 can be carried out using the first pressure measuring device 31.

[0084] For this purpose, the ion source 10 is preferably assigned a control device 21, which is at least temporarily connected and communicates with various components of the ion source 10 via suitable interfaces. For example, the control device 21 is connected to the mass flow controller 17 via an interface 23, to the first pressure measuring device 31 via an interface 24, to the pre-acceleration device 19 via an interface 25, to the vacuum pump 22 via an interface 26, to the cathode 13a via an interface 27, and to the anode 13b via an interface 28. These interfaces are exemplary in nature and serve to illustrate the control device 21 and its function, so that the invention is naturally not limited to the interfaces shown.

[0085] For example, the ion source 10 is only enabled or the ionization process is only started when the first pressure measuring device 31 measures that the pressure value, in particular the vacuum pressure, in the ion generation chamber 11 falls below a certain predetermined pressure value. A switch device (not shown) can also be used to bypass the pressure measuring device 31 at the beginning of the ionization process, so that the ionization process can be started and / or carried out without the pressure measuring device 31 if necessary.

[0086] For example, the first pressure measuring device 31 can be used to monitor and / or calibrate the mass flow control device 17, which is provided for the supply quantity of the molecules 15 to be ionized into the ion generation chamber 11. This will be illustrated by an example:

[0087] The mass flow controller 17 is connected to the control device 21 via the interface 23. Pressure values ​​are measured by the first pressure measuring device 31 in the ion generation chamber 11 and compared with target values. The comparison takes place in the control device 21, with the pressure values ​​generated by the first pressure measuring device 31 being transmitted to the control device 21 via the interface 24. To ensure that the target values ​​and the actually measured values ​​match, the mass flow controller 17 is actuated as needed, for example, by opening or reducing the size of the inlet opening of the supply line 14 into the ion generation chamber 11 accordingly.

[0088] In a preferred embodiment, the first pressure measuring device 31 is designed in the form of a gas friction manometer. An exemplary embodiment of such a gas friction manometer will now be described with reference to Figure 2. The individual components of the gas friction manometer are located in the housing 33. A feature of the gas friction manometer is a vacuum tube 35 or measuring tube, which has a closed end 35b on one side and is connected to the ion generation chamber at its other end. The connection direction is indicated here by the arrow 35a.

[0089] The gas friction manometer comprises a magnet and coil system. Figure 2 shows examples of permanent magnets 37a, 37b, as well as drive coils 38, levitation / stabilization coils 39, speed detection coils 40, and vibration damping coils 41.

[0090] A sphere 36 is mounted frictionlessly in a magnetic field. The magnetic field is generated by permanent magnets 37a, 37b. To maintain altitude, the magnetic field of the permanent magnets 37a, 37b is superimposed with slowly varying direct current (position control) and high frequency (impedance measurement) to determine altitude. Horizontally, the sphere 36 is passively stabilized (stable equilibrium). An external rotating field (= 400 Hz) causes the sphere 36 to rotate. A speed detection coil 40 measures the decrease in rotational speed, and the particle density of the gas is measured from the friction. With this method, only the global properties of the sphere 36 are included in the measurement and are stored with a factor (calibration factor); the rest of the arrangement is not variable or subject to error.The gas friction manometer has a simple design (a rotating 36-gauge ball), operates contactlessly and wear-free, and is operated by electromagnetic forces in a vacuum. The gas friction manometer therefore has no electrically or mechanically stressed components and achieves correspondingly high long-term stability (drift < 1% / year). It is also robust and corrosion-resistant (all-metal). Since the measurement signal is based on the change in the rotation frequency of a spherical body and not on changes in distance or ionization, the process is far less affected by temperature, aging, or coating effects.

[0091] List of reference symbols

[0092] 10 ion source

[0093] 11 ion generation chamber 11a chamber wall

[0094] 11b Chamber interior

[0095] 12 Connection for a pressure measuring device

[0096] 13a Cathode

[0097] 13b Anode

[0098] 14 Supply of molecules to be ionized

[0099] 15 Molecules to be ionized

[0100] 16 ions

[0101] 17 Mass flow controller device

[0102] 18 Output for generated ions

[0103] 16a ion beam

[0104] 19 Pre-acceleration device

[0105] 20 Lens device

[0106] 21 Control device

[0107] 22 Vacuum pump

[0108] 23 Interface

[0109] 24 Interface

[0110] 25 Interface

[0111] 26 Interface

[0112] 27 Interface

[0113] 28 Interface

[0114] 29 Magnet

[0115] 30 pressure measuring device

[0116] 31 First pressure measuring device (gas friction manometer)

[0117] 32 Vertical alignment

[0118] 33 housings

[0119] 34 connecting flange

[0120] 35 Vacuum tube (measuring tube) 35a Connection direction to the ion generation chamber b Closed end of the vacuum tube Ball a Permanent magnet b Permanent magnet Drive coil Levitation Z-stabilization coil Speed ​​detection coil Vibration damping coil

Claims

Patent claims 1. Ion source (10) for generating ions (16) or ion beams (16a), comprising an ion generation chamber (11) for generating the ions (16), and a pressure measuring device (30) associated with the ion generation chamber (11), wherein the pressure measuring device (30) has a first pressure measuring device (31), which is designed in particular in the form of a gas friction manometer, or which in particular has a gas friction manometer.

2. Ion source according to claim 1, characterized in that the first pressure measuring device (31) is connected to the ion generation chamber (11), or that the first pressure measuring device (31) is arranged in the ion generation chamber (11), and / or that the first pressure measuring device (31) is aligned vertically (32) to the ion generation chamber (11).

3. Ion source according to claim 1 or 2, characterized in that the ion generation chamber (11) is designed as an ion generation chamber with negative pressure, in particular as a vacuum-tight ion generation chamber.

4. Ion source according to one of claims 1 to 3, characterized in that a cathode (13a), in particular in the form of a filament, and an anode (13b) are arranged in the ion generation chamber (11), and that in particular the first pressure measuring device (31) is provided spatially spaced from the cathode (13a).

5. Ion source according to one of claims 1 to 4, characterized in that the ion generation chamber (11) is connected to a supply (14) for molecules (15) to be ionized, in particular to a gas supply, and that the supply (14) cooperates in particular with a mass flow control device (17).

6. Ion source according to one of claims 1 to 5, characterized in that the ion source (11) has an extraction device which is used to form an ion beam (16a) and / or to align an ion beam (16a) and / or to extract ions (16) is provided from the supplied molecules (15) to be ionized, or that such an extraction device is assigned to the ion source (10).

7. Ion source according to one of claims 1 to 6, characterized in that the ion generation chamber (11) has an outlet (18) for the generated ions (16) and / or for the generated ion beam (16a), and / or that a pre-acceleration device (19) is provided in the ion generation chamber (11), and / or that a lens device (20) is provided in the ion generation chamber (11) 8. Ion source according to one of claims 1 to 7, characterized in that the pressure measuring device (30), in particular the first pressure measuring device (31), is designed or provided for controlling and / or monitoring the ion source (10), in particular for determining and / or regulating and / or monitoring important parameters of the ion source (11), in particular control parameters, in particular for controlling and / or monitoring the mass flow control device (17), and / or for measuring the pressure within the ion generation chamber (11), and / or for determining the cleanliness of the components within the ion generation chamber (11), and / or for determining the tightness of the ion source (10).

9. Ion source according to one of claims 1 to 8, characterized in that the ion source (10) is designed as an ion source for electron ionization.

10. ion generating device, comprising • an ion source (10) with an ion generation chamber (11) for generating the ions (16), and a pressure measuring device (30) associated with the ion generation chamber (11), wherein the pressure measuring device (30) has a first pressure measuring device (31), which is designed in particular in the form of a gas friction manometer, or which in particular has a gas friction manometer, in particular an ion source (10) according to one of claims 1 to 9; • an extraction device which is provided for forming an ion beam (16a) and / or for aligning an ion beam (16a) and / or for extracting ions (16) from the supplied molecules (15) to be ionized, which at least for Part is part of the ion source (10) or which is connected to the ion source (10); • a device for accelerating the ions generated in the ion source (10).

11. A method for handling an ion source (10), in particular for generating ions (16) in an ion source (10), in particular an ion source (10) according to one of claims 1 to 9, wherein the ion source (10) is provided such that ions (16) are generated in an ionization process from molecules (15) to be ionized in an ion generation chamber (11) of the ion source (10), characterized in that before and / or during and / or after the ionization process, pressure values ​​at / in the ion generation chamber (11) are recorded or determined via a pressure measuring device (30) assigned to the ion generation chamber (11), wherein the pressure measuring device (30) has a first pressure measuring device (31), which is designed in particular in the form of a gas friction manometer, or which in particular has a gas friction manometer.

12. The method according to claim 11, characterized by the following steps: a) Molecules (15) to be ionized, in particular in a gas stream, are fed via a feed (14) into the ion generation chamber (11) of the ion source (10); b) In the ionization process, ions (16) are generated from the molecules (15) to be ionized in the ion generation chamber (11).

13. Method according to claim 11 or 12, characterized in that the ion source (10) is released or the ionization process is started when the pressure measuring device (30), in particular the first pressure measuring device (31), measures that the pressure value, in particular the vacuum pressure in the ion generation chamber (11), falls below a certain predetermined pressure value.

14. Method according to one of claims 11 to 13, characterized in that by means of the pressure measuring device (30), in particular by means of the first pressure measuring device (31), a mass flow control device (17) which is provided for the supply of the molecules (15) to be ionized is controlled and / or monitored and / or calibrated.

15. Method according to one of claims 11 to 14, characterized in that the Pressure measuring device (30), in particular the first pressure measuring device (31), which ion source (10) controls and / or monitors, in particular determines and / or regulates and / or monitors important parameters of the ion source (10), and / or measures the pressure within the ion generation chamber (11), and / or determines the cleanliness of the components within the ion generation chamber (11), and / or determines the tightness of the ion source (10).

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