MEMS image forming element with built-in voltage generator

Abstract

The present disclosure describes an image forming element having a semiconductor chip having a microelectromechanical system (MEMS) device (210) and a voltage generator (220), each voltage generator being configured to generate a voltage used by one or more of the MEMS devices. A floating ground can be used to add a voltage to a voltage generated by the voltage generator. The semiconductor chip can include an electrical connection (235), wherein each voltage generator is configured to provide a voltage to one or more MEMS devices via the electrical connection. The MEMS devices can define a boundary in the semiconductor chip, within which the MEMS devices, the voltage generator, and the electrical connection are located. Each MEMS device can generate an electrostatic field to manipulate electron beamlets of a multi-beam charged particle microscope. The MEMS devices can be organized into groups based on a distance to a reference position (e.g., an optical axis) in the semiconductor chip.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims priority to U.S. Application No. 62 / 830,398, filed on April 6, 2019, which is incorporated herein by reference in its entirety. Technical Field

[0003] The present disclosure relates generally to systems using charged particle microscopes, such as scanning electron microscopes (SEMs), and more particularly to image forming elements used in such systems. Background Art

[0004] In a manufacturing process for making integrated circuit (IC) components, unfinished or completed circuit components are inspected to ensure that they are manufactured according to a specified design and are free of defects. Inspection systems utilizing optical microscopes or charged particle (e.g., electron) beam microscopes (such as multi-beam SEMs) may be employed. As the physical dimensions of various features of IC components continue to shrink, the accuracy and throughput achieved by these inspection systems become more important. Currently, these systems tend to be limited, at least in part, by the number of scanning electron beamlets generated by the system for inspection and the image forming elements used to manipulate these electron beamlets. Therefore, there is a great need for improved implementations of image forming elements that enable the number of electron beamlets used in a multi-beam SEM to be proportionally increased. Summary of the invention

[0005] A simplified overview of one or more aspects of various embodiments of the present disclosure is presented below in order to provide a basic understanding of these aspects. This overview is not an extensive overview of all contemplated aspects, and is neither intended to identify key or important elements of all aspects, nor to delineate the scope of any or all aspects. Its sole purpose is to present some concepts of one or more aspects in a simplified form as a prelude to a more detailed description presented later.

[0006] An aspect of one embodiment describes a semiconductor chip having a plurality of microelectromechanical systems (MEMS) devices and a plurality of voltage generators, wherein each of the voltage generators is configured to generate a voltage used by one or more of the MEMS devices (e.g., by a corresponding one of the MEMS devices). The semiconductor chip may also have a plurality of electrical connections, wherein each of the voltage generators is configured to provide a voltage to the one or more MEMS devices through one of the electrical connections. Each of the MEMS devices is configured to generate an electric field to manipulate a beamlet of several electron beamlets in a multi-beam charged particle microscope (e.g., a scanning electron microscope (SEM), a scanning ion microscope, a transmission electron microscope (TEM), or a scanning proton microscope).

[0007] Another embodiment aspect describes a semiconductor chip having a plurality of MEMS devices defining a boundary in the semiconductor chip, and having a plurality of voltage generators located within the boundary, wherein each of the voltage generators is configured to generate a voltage used by one or more of the MEMS devices (e.g., by a corresponding one of the MEMS devices). The semiconductor chip may also have a plurality of electrical connections located within the boundary, wherein each of the voltage generators is configured to provide a voltage to the one or more MEMS devices through one of the electrical connections.

[0008] An aspect of yet another embodiment describes a semiconductor chip having a plurality of MEMS devices, wherein each of the MEMS devices is part of one of a plurality of groups of MEMS devices, and wherein each group is based on a distance of the MEMS devices in the group to a reference location in the semiconductor chip. The semiconductor chip may also have a plurality of voltage generators, wherein each of the voltage generators is configured to generate a voltage used by one or more of the MEMS devices, and may also have a plurality of electrical connections, wherein each of the voltage generators is configured to provide a voltage to one of the MEMS devices through one of the electrical connections.

[0009] Aspects of yet another embodiment describe a semiconductor chip having a plurality of MEMS devices and a plurality of voltage generators, wherein each of the voltage generators is configured to generate a secondary voltage that is added to a primary voltage for the voltage generator, wherein the primary voltage is provided by a separate voltage generator, and wherein the added voltage is used by one of the MEMS devices (e.g., by a corresponding one of the MEMS devices). The semiconductor chip may also have a plurality of electrical connections, wherein each of the voltage generators is configured to provide a voltage to one of the MEMS devices through one of the electrical connections.

[0010] To achieve the foregoing and related purposes, aspects of the embodiments include the features described below and particularly pointed out in the claims. The following description and the accompanying drawings set forth in more detail certain illustrative features of one or more aspects. However, these features are merely indicative of a few of the various ways in which the principles of the various aspects may be employed, and the present description is intended to include all such aspects and their equivalents. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] Figure 1A It is a figure which shows SEM.

[0012] Figure 1B is a diagram illustrating an image forming element of a source conversion unit used in a SEM.

[0013] Figure 2 is a diagram illustrating a cross-sectional view of a semiconductor chip having a micro-electromechanical system (MEMS) device and a built-in voltage generator according to some aspects of the present disclosure.

[0014] FIG. 3A to FIG. 3C is an illustration of some aspects of the present disclosure Figure 2 Figure 1 shows different top views of a semiconductor chip with some layers removed and in which the MEMS device is a microlens.

[0015] FIG. 4A to FIG. 4C is an illustration of some aspects of the present disclosure Figure 2 Figure 2 shows different top views of a semiconductor chip with some layers removed and in which the MEMS device is a microdeflector or an stigmator.

[0016] Figure 5 is a diagram illustrating a partial top view of a semiconductor chip having a MEMS device group and a built-in voltage generator according to some aspects of the present disclosure.

[0017] Figure 6 is a diagram illustrating the use of primary and secondary voltages by a semiconductor chip having a MEMS device and a built-in voltage generator according to some aspects of the present disclosure.

[0018] Fig. 7A and Figure 7B is a diagram illustrating the use of group-level voltages by a semiconductor chip having a MEMS device and a built-in voltage generator, according to some aspects of the present disclosure. DETAILED DESCRIPTION

[0019] As described above, systems using optical microscopes or charged particle (e.g., electron) beam microscopes (such as multi-beam SEMs) can be employed for inspection of completed or unfinished IC components (e.g., semiconductor wafer or die inspection). As the critical dimensions of IC components continue to shrink, resulting in an increasing number of transistors, and as the overall throughput of the detection system is also pushed up, the accuracy and speed achieved by these detection systems become more important. One of the key components of these systems is an image forming element, which is used to manipulate the electron beamlets aimed at the inspected target (e.g., control their direction). By using an increasing number of electron beamlets, multiple areas of a target (or multiple targets) can be scanned simultaneously, thereby achieving higher throughput. Therefore, it is desirable to have an image forming element with a scalable architecture that allows processing of an increasing number of electron beamlets. The present disclosure describes various techniques for achieving scalability in an image forming element by implementing a semiconductor chip architecture, wherein a voltage generator is used to drive multiple micro-electromechanical systems (MEMS) devices in the image forming element, and the micro-electromechanical systems (MEMS) devices are built locally, that is, directly in the image forming element.

[0020] In a multibeam SEM, the electron beamlets can be transferred by a source conversion unit (see, for example, Figure 1A In the source conversion unit, the image forming element (e.g., see Figure 1B The image forming element 158 ​​in the schematic diagram 100b of is used as part of the source conversion unit to generate multiple electron beamlets from a single electron source. In the image forming element, there may be microlenses, microdeflectors or stigmators for manipulating the electron beamlets. All of these microlenses, microdeflectors or stigmators can be manufactured on a silicon chip (for example, on a semiconductor chip) by MEMS technology. The number of MEMS structures or devices in the silicon chip is generally related to or corresponds to the number of electron beamlets used by the SEM. In order to operate the source conversion unit in the current design, interconnects are used to connect the various MEMS devices in the image forming element to voltage generators that provide operating voltages for these devices. However, these voltage generators are located outside the source conversion unit. These interconnects need to be manufactured on the same silicon chip as the MEMS devices and then connected to the external voltage generators via additional cables.

[0021] As described above, one way to improve the overall throughput of a multi-beam SEM used in a wafer or semiconductor inspection system is to increase the number of electron beamlets to further parallelize the inspection process. If the number of electron beamlets increases, the number of MEMS devices required for the microlenses, microdeflectors, or stigmators on each silicon or semiconductor chip also needs to increase. This increase in the number of MEMS devices makes the density of MEMS devices greater (e.g., the spacing between MEMS devices becomes smaller) and the density of interconnects between the MEMS structures and the external voltage generators also increases. These problems can make the design, installation, and maintenance of the SEM cumbersome.

[0022] In addition to the density issues caused by the increase in the number of electron beamlets and MEMS devices, another problem that arises is that the voltage that needs to be applied to these MEMS devices is already high, and may even need to be further increased based on the increase in the number of MEMS devices. A certain amount of space is usually required between any two adjacent interconnects so that there is no electrical breakdown or high leakage current, and the source conversion unit can operate normally. As the voltage is further increased, the amount of space between the interconnects needs to be expanded accordingly. This need for additional spacing between interconnects also limits the ability to increase the number and density of MEMS devices in the image forming element. When trying to scale up the production volume of multi-beam SEMs, the huge difficulty that existing designs must increase the number of MEMS devices in the source conversion unit is an obvious bottleneck.

[0023] The present disclosure describes a new semiconductor chip design or architecture for image forming elements in a source conversion unit that allows the number of MEMS devices to be scaled up more easily. In addition to MEMS devices (e.g., microlenses, microdeflectors, or stigmators) and interconnects, local voltage generators can be embedded, integrated, or built into semiconductor or silicon chips. Each local voltage generator can provide one or more voltages required to drive one or more of the microlenses, microdeflectors, or stigmators surrounding it. In this way, the long interconnects used to travel from each MEMS device to the external voltage generator in the current design are replaced by short local interconnects that now travel from each MEMS device to the local built-in voltage generator. This approach greatly reduces the area required for the interconnects. The only long wires that may still be needed are shared ground wires, power wires, and wires for additional data communication buses or similar data distribution. In order to further reduce the number of long wires and the area required for the long wires, the wires used for the data communication bus can also be eliminated by using power wires to send and receive communication data to each local voltage generator and from each local voltage generator. In this way, the above-mentioned problems that prevent current designs from scaling up the number of MEMS devices in a source conversion unit no longer exist, and this is achieved without sacrificing either the flexibility or functionality of the source conversion unit.

[0024] The aspects outlined above have the advantage of converting the longest interconnects used in existing designs for MEMS devices in semiconductor chips (e.g., image forming element silicon chips) into short local interconnects. This reduces the number of interconnects that currently need to be made through vacuum interfaces or to external modules, improving overall SEM design, installation, and maintenance. In addition, this approach increases the reliability of the source conversion unit and reduces the difficulties that typically arise during module assembly and system-level integration for the source conversion unit, which can even involve automated assembly by machines. In addition, the voltage or voltages used by each MEMS device can be independently adjusted by having a local voltage generator, again giving greater flexibility to address any local variations in the MEMS device.

[0025] The present disclosure also describes a variety of techniques by which, on each independent MEMS device layer (such as a layer for microlenses, microdeflectors, or stigmators), for example, those MEMS devices that have the same or substantially similar distance from the center of the grid (e.g., the optical axis of the image forming element) can be grouped together. In each group, a local voltage generator can generate a low-level voltage based on a predefined tolerance range and can share the same floating ground. Each floating ground can be offset or biased with a specific voltage (e.g., a primary voltage) by a voltage source or voltage generator (e.g., a high voltage power supply) located outside the MEMS device. The offset or bias voltage (e.g., the primary voltage) is then added to the voltage provided by the local voltage generator (e.g., the secondary voltage). The voltage generator that provides the offset or bias voltage can be built into the same semiconductor chip as the MEMS device, but away from its corresponding MEMS device group, or can be placed outside the image forming element with the MEMS device, but close to the image forming element.

[0026] The built-in voltage generators in each group can be configured to generate low-level voltages for microlenses, microdeflectors, or stigmators. Since the voltage range requirements of these voltage generators are much lower than the voltage applied to the floating ground of most groups, the size of the local voltage generators can be significantly reduced. This means that a higher density of MEMS devices can be achieved in a semiconductor chip because the space required for the local voltage generators is much less than if the grouping method with floating ground is not used. In this way, multi-beam SEMs can be further scaled up by increasing the density of MEMS devices in the image forming element.

[0027] The additional aspects outlined above have the advantage that the size of all local voltage generators can be further reduced without increasing the complexity or affecting the flexibility of the image forming element.

[0028] Reference will now be made in detail to example aspects of the embodiments, examples of which are shown in the accompanying drawings. The following description refers to the accompanying drawings, wherein, unless otherwise specified, the same reference numerals in different drawings represent the same or similar elements. The embodiments set forth in the following description of example aspects of the embodiments do not represent all embodiments consistent with the present disclosure. Instead, they are merely examples of structures and processes consistent with aspects of the embodiments (related to the disclosures recorded in the claims). For example, although some aspects of the present disclosure are described in the context of an inspection system that uses electronic scanning of samples and detection of defects, these aspects may also be applicable to other types of systems in which multiple charged particle beams are manipulated.

[0029] Figure 1A FIG100a is shown illustrating a general representation of a SEM that may be part of an inspection system. In this example, the SEM is an off-axis SEM, however some of the features described herein in conjunction with the image forming element are also applicable to on-axis SEMs. The SEM system includes a source 110 (or similar electron or radiation source), a gun aperture plate 145, a condenser lens 150, a source conversion unit 155, a primary projection system 160, and a target 130, all of which are aligned with a primary axis 140. A beam splitter 175 and a deflection scanning unit 180 may be placed inside the primary projection system 160. The primary projection system 160 may also include an objective lens 185. The SEM in FIG100a also includes a secondary imaging system 165, which, together with the detector 120, is aligned with the secondary axis 170.

[0030] The source 110 may include a cathode, an extractor, or an anode, wherein primary electrons may be emitted from the cathode and extracted or accelerated to form a primary electron beam 115 .

[0031] The aperture plate 145 may be used to block unused peripheral electrons of the primary electron beam 115 to reduce a Coulomb effect that may enlarge the size of each of the probe spots on the target 130 and thus deteriorate inspection resolution.

[0032] The condenser lens 150 may be used to focus the primary electron beam 115. The current of the electron beamlets downstream of the source conversion unit 155 may be varied by adjusting the focusing capability of the condenser lens 150 or by changing the radial size of the corresponding beam limiting apertures within the beam limiting aperture array 157 in the source conversion unit 155 (see, for example, Figure 1B Figure 100b).

[0033] The source conversion unit 155 may include at least one image forming element 158 ​​as described above (eg, see Figure 1B100b) and a beam limiting aperture array 157. The image forming element 158 ​​may have a plurality of microlenses, microdeflectors or stigmators to form a parallel image (virtual or real) from a plurality of primary electron beamlets 156 from the primary electron beam 115, and the beam limiting aperture array 157 may limit the number of electron beamlets 156.

[0034] The objective lens 185 in the primary projection system 160 may focus the electron beamlets onto the target 130 for inspection, and may form a plurality of detection points on the surface of the target 130 based on the number of primary electron beamlets 156 provided by the source conversion unit 155 .

[0035] The beam splitter 175 in the primary projection system 160 can be a Wien filter type beam splitter that generates an electrostatic dipole field and a magnetic dipole field. If they are applied, the electrostatic dipole field can exert a force on the electrons of the primary electron beamlet that is equal in magnitude and opposite in direction to the force exerted on the electrons by the magnetic dipole field, and thus the electron beamlet can pass through the beam splitter 175 in a straight line at a zero deflection angle.

[0036] The deflection scanning unit 180 in the primary projection system 160 can deflect the primary electron beamlet to scan the probe point on the surface of the target 130. In response to the incidence of the electron beamlet at the probe point, the secondary electron beamlet 135 can be emitted from the target 130 and has electrons with energy distribution, including secondary electrons (e.g., energy ≤ 50 eV) and backscattered electrons (e.g., energy between 50 eV and the landing energy of the electron beamlet). The beam splitter 175 can direct the secondary electron beamlet to the secondary imaging system 165, which in turn can focus the secondary electron beamlet onto the surface of the detector 120.

[0037] The beam splitter 175 can be configured to deflect the secondary electron beamlet 135 by an angle α in the direction of the secondary imaging system 165. The angle α can be determined as the angle between the primary axis 140 and the secondary axis 170, so that the angle α can represent the separation angle between the on-axis primary electron beam 115 and the secondary electron beamlet 135, which is directed by the beam splitter 175 in the direction of the secondary imaging system 165 and the detector 120. In some embodiments, the angle α can be set in the range of 5 degrees to 25 degrees. The detector 120 can be a secondary electron (SE) detector including a single silicon PIN photodiode array.

[0038] Figure 1BFIG. 100 b is shown, which illustrates an image forming element 158 ​​of a source conversion unit 155 used in the above-described SEM. When multiple electron beams or beamlets are used in the SEM, they can be generated from multiple sources or a single source. If the electron beams come from multiple sources, multiple columns can scan and focus the electron beams onto the surface of the target, and the signals generated by the electron beams can be detected by detectors in the columns, respectively. An apparatus using beams from multiple sources can be referred to as a multi-column apparatus. If the charged particle beam comes from a single source, as in Figure 1A 100a in SEM, the source conversion unit can be used to form multiple virtual or real images of a single beam source. The source conversion unit can have a conductive layer with multiple apertures or openings that separate charged particles from a single source into multiple electron beamlets. The source conversion unit can have many microelements (e.g., MEMS devices) typically organized into an array that can affect how the electron beamlets are manipulated to form multiple virtual or real images of a single source.

[0039] Figure 1A The source conversion unit 155 in FIG. 100a is Figure 1B 100b is shown in more detail and includes a beam limiting aperture array 157 and an image forming element 158. The beam limiting aperture array 157 blocks part of the primary electron beam 115 to produce a primary electron beamlet 156, which is then manipulated by the image forming element 158. There may be more than one image forming element 158 ​​stacked on top of each other to produce a combined effect (see the dashed box representing multiple image forming elements 158). The image forming element 158 ​​can be made using a semiconductor chip. Figures 2 to 7B Details are provided of various semiconductor chip designs or architectures that enable the image forming element 150 to handle increasing numbers of electron beamlets 156 .

[0040] Figure 2 A diagram 200 is shown illustrating a cross-sectional view of a semiconductor chip 205 having a MEMS device 210 and a built-in voltage generator 220 (eg, a local voltage generator) according to some aspects of the present disclosure. The semiconductor chip 205 may be part of the image forming element 158 ​​described above in connection with the source conversion unit 155 of the multi-beam SEM.

[0041] The semiconductor chip 205 is shown as including a plurality of MEMS devices 210. Each of the MEMS devices 210 may be a microlens, a microdeflector, or an stigmator. For example, the semiconductor chip 205 may have an array of MEMS devices 210, all of which may be of the same type (e.g., all microlenses), or in some cases, some of which may be of one type (e.g., microlenses) and others of different types (e.g., microdeflectors). That is, in the above-described image forming elements (e.g., image forming element 158), in each layer, the same type of MEMS device will typically be formed. However, the present disclosure also allows for situations where the types of MEMS devices in the same layer may be different.

[0042] Each of the MEMS devices 210 may include one or more electrostatic elements 215 (e.g., metal elements or metal contacts) configured to receive a voltage from a voltage generator 220 to generate an electrostatic field that steers or controls an electron beamlet (e.g., electron beamlet 156). In some cases, such as for a microlens, the MEMS device 210 may have a single electrostatic element 215, while in other cases, such as for a microdeflector and an stigmator, the MEMS device 210 may have multiple electrostatic elements 215.

[0043] like Figure 2 As shown in FIG. 200 , the voltage generator 220 may be embedded, integrated, or assembled into the semiconductor chip 205 . Each of these voltage generators 220 may consist of a single chip or integrated circuit that includes a local control unit (LCU) of the voltage generator, a digital-to-analog converter (DAC), and an amplifier or driver circuit for driving the surrounding MEMS device 220 . In some cases, the voltage required by the MEMS device 210 may be quite high. Due to the high voltage requirements, the processes for the LCU, DAC, and driver circuits may not be made into a single chip or integrated circuit using the same process node or process technology, or the processes for each of the functions may be different in order to optimize the performance of each functional block in the voltage generator 220 . In those cases, instead of using a single chip or integrated circuit, the voltage generator 220 may be a stack of multiple chips, each of which may implement a function or part of a function of the voltage generator 220 .

[0044] In order to provide appropriate supply voltages and grounds to the voltage generator 220 and ultimately to the MEMS device 210, a stack or layer is deposited or formed over the semiconductor chip 205, such as Figure 2200 in FIG. Such a stack of layers may include a plurality of isolation layers 230, a metal layer 235 for local voltage distribution, a metal layer 240 for a ground plane, and a metal layer 250 for a power supply. The metal layer 235 for local voltage distribution serves as a conductor that provides electrical connectivity between the voltage generator 220 and the MEMS device 210. The metal layer 240 for a ground plane provides one or more ground planes (including a floating ground) that are electrically connected to the voltage generator 220. Although Figure 2 Figure 200 in Figure 200 shows a single ground plane, but multiple ground planes can be provided, including multiple floating grounds. Metal layer 250 for power supply provides one or more power supply voltages outside semiconductor chip 205 (or in semiconductor chip 205, but outside the array of MEMS devices 210), where these one or more power supply voltages are electrically connected to voltage generator 220.

[0045] Figure 2 The stack of layers shown in diagram 200 in A is provided by way of illustration and not limitation. For example, more or fewer layers may be used in the stack of layers, and the order of the layers shown may be changed to accommodate different voltages, ground planes, and interconnect distribution methods.

[0046] In addition, the dotted lines that pass through the stack of layers and are shown above the MEMS device 210 represent apertures or openings in the stack of layers through which the electron beamlets 156 can reach the MEMS device 210. Although not shown, the walls of the apertures or openings can have a metal coating and can be connected to a certain reference voltage or ground to avoid charging effects due to accumulation of electrons or charged particles. The walls can also be part of a MEMS device or structure, such as part of a microlens, microdeflector, or an stigmator.

[0047] FIG. 3A to FIG. 3C Figures 300a, 300b and 300c are shown, which illustrate Figure 2 FIG. 200 shows a different top view of a semiconductor chip 205 with certain layers removed, and wherein the MEMS devices 210 are microlenses. The MEMS devices 210 as microlenses are shown with a single electrostatic element 215 formed around the periphery of each MEMS device 210. Figure 3A In FIG. 300 a , a partial top view of a semiconductor chip is shown having an array of MEMS devices 210 and having a metal layer 250 for power supply for distributing one or more power supply voltages. The metal layer 250 for power supply is placed on the isolation layer 230 .

[0048] Figure 3BFIG. 300 b shows a partial top view of an array with MEMS devices 210 and metal layer 240 for a ground plane, wherein metal layer 250 for power supply and isolation layer 230 are removed.

[0049] Figure 3C FIG. 300 c in FIG. 300 shows a partial top view with an array of MEMS devices 210, several voltage generators 220 located in a subset of the MEMS devices 210 to provide voltage to the MEMS devices 210 in the subset, and a metal layer 235 for local voltage distribution (e.g., local electrical connections or wires) for providing the voltage generated by the voltage generators 220 to the MEMS devices 210. The metal layer 235 for local voltage distribution is disposed on the isolation layer 230.

[0050] FIG. 4A to FIG. 4C Figures 400a, 400b, and 400c are shown, illustrating a Figure 2 2 shows a different top view of a semiconductor chip 205 with some layers removed, and wherein the MEMS device 210 is a micro deflector or an stigmator. The MEMS device 210 as a micro deflector or an stigmator is shown to have more than one electrostatic element 215 formed around the periphery of each MEMS device 210. Figure 4A In FIG. 400 a , a partial top view of a semiconductor chip is shown, which has an array of MEMS devices 210 and has a metal layer 250 for power supply for distributing one or more power supply voltages. The metal layer 250 for power supply is arranged on the isolation layer 230 .

[0051] Figure 4B The diagram 400b in FIG. 4 shows a partial top view of the array with the MEMS devices 210 and the metal layer 240 for the ground plane, wherein the metal layer 250 for the power supply and the isolation layer 230 are removed.

[0052] Figure 4C FIG. 400 c in FIG. 4 shows a partial top view with an array of MEMS devices 210, several voltage generators 220 located in a subset of the MEMS devices 210 to provide voltage to the MEMS devices 210 in the subset, and a metal layer 235 for local voltage distribution (e.g., local electrical connections or wires) for providing the voltage generated by the voltage generators 220 to the MEMS devices 210. The metal layer 235 for local voltage distribution is disposed on the isolation layer 230.

[0053] and Figure 3CCompared to FIG. 300c in FIG. 300b (in which the MEMS device 210 has a single electrostatic element 215 and only one electrical connection is required between the MEMS device 210 and the voltage generator 220), in this example, each MEMS device 210 has multiple electrostatic elements 215 and therefore multiple electrical connections are required between the MEMS device 210 and the voltage generator 220.

[0054] It should be understood that FIG. 3A to FIG. 4C The embodiments shown in are provided by way of illustration and not limitation. For example, the number of MEMS devices 210 associated with a particular voltage generator 220 may be more or less than that shown in the figure. Although a 2x2 array of MEMS devices 210 is shown as being associated with each voltage generator 220, the subset may be different, including a larger array (e.g., 3x3), a different type of array (e.g., a rectangular array instead of a square array), or some other arrangement. In addition, the positioning of the voltage generator 220 need not be as shown, but may vary across the semiconductor chip 205. Similarly, the size of the voltage generator 220 need not be the same or consistent, but may vary across the semiconductor chip 205.

[0055] Combination FIG. 3A to FIG. 4C The present disclosure describes a first embodiment of a semiconductor chip (e.g., semiconductor chip 205) including a plurality of MEMS devices (e.g., MEMS device 210), a plurality of voltage generators (e.g., local voltage generators 220), wherein each of the voltage generators is configured to generate a voltage used by one or more of the MEMS devices (e.g., by a corresponding one of the MEMS devices). The semiconductor chip may be part of an image forming element configured for use in a multi-beam SEM. The semiconductor chip may also include a plurality of electrical connections (e.g., metal layer 235 for local voltage distribution), wherein each of the electrical connections includes a plurality of wires, and wherein each of the voltage generators is configured to provide a voltage to one of the MEMS devices through one of the electrical connections. In this first embodiment, each of the MEMS devices is configured to generate an electric field to manipulate a beamlet in a plurality of electron beamlets in a multi-beam charged particle microscope (e.g., a scanning electron microscope (SEM), a scanning ion microscope, a transmission electron microscope (TEM), or a scanning proton microscope).

[0056] For example, each of the MEMS devices may be a microlens, a microdeflector, or an stigmator. In addition, the MEMS device and the voltage generator may be integrated in a semiconductor chip.

[0057] In one aspect of this first embodiment of the semiconductor chip, the number of MEMS devices may be equal to or greater than the number of voltage generators. Alternatively, the number of MEMS devices may be less than the number of voltage generators.

[0058] In another aspect of the first embodiment of the semiconductor chip, the MEMS devices are arranged into subsets, wherein the voltage generator includes one voltage generator for each subset, and wherein one of the voltage generators is configured to: provide a voltage generator for each of the MEMS devices in the corresponding subset (e.g., see Figure 3C 300c in FIG. 300c) generates a voltage (e.g., a separate voltage). One voltage generator can provide a voltage to each of the MEMS devices in the corresponding subset through a separate electrical connection in the electrical connections. Each of the MEMS devices in the corresponding subset can be a microlens having a single electrostatic element (e.g., electrostatic element 215) to which a separate voltage is applied. The number of MEMS devices in each subset can be the same, or the number of MEMS devices can be different for different subsets. In addition, one voltage generator can be located at the center of the MEMS devices in the corresponding subset (e.g., see FIG. 300c in FIG. 300c). Figure 3C Figure 300c).

[0059] In another aspect of the first embodiment of the semiconductor chip, the MEMS devices are arranged into a plurality of subsets, wherein the voltage generator includes one voltage generator for each subset, and wherein one of the voltage generators is configured to: provide a voltage generator for each of the MEMS devices in the corresponding subset (e.g., see Figure 4C 400c in the figure) generates multiple voltages (e.g., separate voltages). One voltage generator can provide multiple voltages to each MEMS device in the corresponding subset through multiple electrical connections in the electrical connections. Each MEMS device in the corresponding subset is a micro-deflector or an stigmator having multiple electrostatic elements to which multiple voltages are applied respectively. The number of MEMS devices in each subset can be the same, or the number of MEMS devices for different subsets can be different. In addition, one voltage generator can be located at the center of the MEMS devices in the corresponding subset (e.g., see Figure 4C 400c).

[0060] In another aspect of this first embodiment of the semiconductor chip, the semiconductor chip may further include a stack of layers arranged above the top surface of the semiconductor chip (eg, see Figure 2200 in FIG. 200 ), wherein the stack of layers is configured to provide one or more power supplies or power supply voltages (e.g., metal layer 250 for power supplies) to power the voltage generators through one or more power supply layers and one or more ground planes (e.g., metal layer 240 for ground planes), and the one or more ground planes are connected to the voltage generators through one or more ground plane layers. The stack of layers may include multiple isolation layers (e.g., see isolation layer 130) to isolate the one or more power supply layers and ground plane layers from each other. Each of the voltage generators is electrically connected to one or more power supplies. As described above, the stack of layers may have openings or apertures, wherein the walls of the openings or apertures may have a metal coating and may be connected to a specific reference voltage or ground to avoid charging effects caused by accumulation of electrons or charged particles. The walls may also be part of a MEMS device such as a microlens, a microdeflector, or an stigmator. In addition, each of the electrical connections connects the MEMS device to a corresponding voltage generator through the stack of layers.

[0061] The present disclosure describes a second embodiment of a semiconductor chip (e.g., semiconductor chip 205) including a plurality of MEMS devices (e.g., MEMS device 210) defining a boundary in the semiconductor chip, and a plurality of voltage generators (e.g., local voltage generator 220) within the boundary, wherein each of the voltage generators is configured to generate a voltage used by one of the MEMS devices. The semiconductor chip may be configured as part of an image forming element for use in a multi-beam charged particle microscope (e.g., SEM, scanning ion microscope, TEM, or scanning proton microscope).

[0062] In one example, the MEMS devices may be arranged in an array, and the boundary may be defined as the periphery of the array or the MEMS devices forming the periphery of the array. The semiconductor chip may also include a plurality of electrical connections (e.g., a metal layer 235 for local voltage distribution) located within the boundary, wherein each of the electrical connections includes one or more wires (e.g., a plurality of wires), and wherein each of the voltage generators provides a voltage to a MEMS device through one of the electrical connections. Each of the MEMS devices in the MEMS device is a microlens, a microdeflector, or an stigmator. The number of MEMS devices is equal to or greater than the number of voltage generators, or alternatively, the number of MEMS devices is less than the number of voltage generators.

[0063] In one aspect of this second embodiment of the semiconductor chip, there is also a stack of layers arranged above the top surface of the semiconductor chip (eg, Figure 2200 in FIG. 1 ), wherein the stack of layers is configured to provide one or more power supplies or power supply voltages (e.g., metal layer 250 for power supplies) to power a voltage generator via one or more power supply layers and one or more ground planes (e.g., metal layer 240 for ground planes), and the one or more ground planes are connected to the voltage generator via one or more ground plane layers.

[0064] Figure 5 A diagram 500 is shown that illustrates a partial top view of a semiconductor chip (e.g., semiconductor chip 205) having MEMS devices 210 arranged in groups and having a built-in voltage generator 220 (e.g., a local voltage generator) for each of the groups, in accordance with certain aspects of the present disclosure. Each group may be based on the distance of the MEMS devices 210 in the group to a reference location in the semiconductor chip. In this example, three groups may be shown, a first group including MEMS devices 210 in a center portion, a second group including MEMS devices 210 in a radius 510a from the center of the semiconductor chip, and a third group including MEMS devices 210 in a radius 510b from the center of the semiconductor chip.

[0065] Also shown in diagram 500 are two voltage generators 220a and 220b for the first group of MEMS devices 210 and the second group of MEMS devices 210, respectively. Although a single local voltage generator is shown for each group for purposes of illustration, each group may have more than one local voltage generator, and these voltage generators need not be of the same size or voltage, and may be located in different places (e.g., need not be adjacent to each other).

[0066] Combined with the above FIG. 3A to FIG. 4C and Figure 5, the present disclosure describes a third embodiment of a semiconductor chip (e.g., semiconductor chip 205) including a plurality of MEMS devices (e.g., MEMS device 210), wherein each of the MEMS devices is part of one of a plurality of groups of MEMS devices, and each group is based on the distance of the MEMS devices in the group to a reference position in the semiconductor chip. In one example, the reference position is the center of a grid formed by the MEMS devices. In other examples, the grid formed by the array of MEMS devices may not have a central symmetrical shape, and the reference position may be based on alignment with an optical axis. In addition, the distance of the MEMS devices in one group to the reference position in the semiconductor chip may be different from the distance of the MEMS devices in another group to the reference position in the semiconductor chip. The semiconductor chip may also include a plurality of voltage generators (e.g., local voltage generator 220), wherein each of the voltage generators is configured to generate a voltage used by one of the MEMS devices in the MEMS devices. The semiconductor chip may be part of an image forming element configured for use in a multi-beam SEM, and the reference position may coincide with or align with the optical axis of the SEM as described above. The semiconductor chip may also include multiple electrical connections (e.g., metal layer 235 for local voltage distribution), wherein each of the electrical connections includes one or more wires (e.g., multiple wires), and wherein each of the voltage generators is configured to provide a voltage to a MEMS device through one of the electrical connections.

[0067] In one aspect of this third embodiment of the semiconductor chip, each of the MEMS devices is configured to generate an electric field to manipulate a beamlet of a plurality of electron beamlets in a multi-beam charged particle microscope. Additionally or alternatively, the MEMS devices define a boundary in the semiconductor chip (e.g., by a periphery of an array of MEMS devices), and the voltage generator and the electrical connections are located within the boundary.

[0068] In other aspects of this third embodiment of the semiconductor chip, each of the MEMS devices is a microlens, a microdeflector, or an stigmator. The number of MEMS devices is equal to or greater than the number of voltage generators, or alternatively, the number of MEMS devices is less than the number of voltage generators. In addition, there may be more than one voltage generator associated with each MEMS device group.

[0069] Figure 6 Diagram 600 is shown illustrating use of primary and secondary voltages by a semiconductor chip (eg, semiconductor chip 205 ) having a MEMS device (eg, MEMS device 210 ) and a built-in voltage generator (eg, local voltage generator 220 ) in accordance with some aspects of the present disclosure.

[0070] As shown in diagram 600, the voltage applied to one of the MEMS devices 210 (or one of the electrostatic elements 215 of the MEMS device 210) can come from the addition of a primary voltage 610 generated or provided by a separate (e.g., external) power source and a secondary voltage 620 generated by the local voltage generator 220. As described above, this can allow the use of a smaller local voltage generator to alleviate density issues while providing a sufficiently high operating voltage. When this method is applied to the above combined Figure 5 When the grouping technique is described in FIG. 500 , the primary voltage 610 can be provided as an offset or bias voltage (e.g., Vgroup) to a floating ground of a group formed, for example, by a metal layer 240 for a ground plane, while the secondary voltage (e.g., ΔV) is generated or provided by a local voltage generator 220 associated with the group.

[0071] Combined with the above Figures 3A to 5 and Figure 6 , the present disclosure describes a fourth embodiment of a semiconductor chip (e.g., semiconductor chip 205) including a plurality of MEMS devices (e.g., MEMS device 210) and a plurality of voltage generators (e.g., local voltage generator 220), wherein each of the voltage generators is configured to generate a secondary voltage (e.g., secondary voltage 620) that is added to a primary voltage (e.g., primary voltage 610) for the voltage generator, wherein the primary voltage is provided by a separate voltage generator, and wherein the added voltage is used by one of the MEMS devices. In some cases, the secondary voltage may be less than the primary voltage, or alternatively, the primary voltage may be less than the secondary voltage. The separate voltage generator may be an external voltage generator to the semiconductor chip, or may be built into the semiconductor chip (although may be located outside the array of MEMS devices). The semiconductor chip may be part of an image forming element configured for use in a multi-beam charged particle microscope. The semiconductor chip may also include multiple electrical connections (e.g., metal layer 235 for local voltage distribution), wherein each of the electrical connections includes one or more wires (e.g., multiple wires), and wherein each of the voltage generators is configured to provide a voltage to a MEMS device through one of the electrical connections.

[0072] In one aspect of the fourth embodiment of the semiconductor chip, each of the MEMS devices is part of one of a plurality of MEMS device groups (eg, see Figure 5500 in FIG. 500 ), and each group is based on the distance of the MEMS devices in the group to a reference location in the semiconductor chip. The semiconductor chip may include a separate floating ground for each MEMS device group, wherein each group uses the same primary voltage, and the primary voltage is provided through the floating ground for the group (e.g., applied to the floating ground as an offset or bias voltage). The semiconductor chip may have additional electrical connections to connect each of the floating grounds to a corresponding separate voltage generator. In some cases, the primary voltage applied to one floating ground and the corresponding MEMS device group is different from the primary voltage applied to another floating ground and the corresponding MEMS device group.

[0073] In one aspect of this fourth embodiment of the semiconductor chip, each MEMS device in one of the groups is a microlens, a microdeflector, or an stigmator having a plurality of electrostatic elements (e.g., electrostatic element 215), and a voltage generator in the voltage generator associated with the group generates a plurality of separate voltages, which are applied to the plurality of electrostatic elements of at least one of the MEMS devices in the group, respectively. For any one of the groups, the added voltage used by one of the MEMS devices in the group may be different from the added voltage used by another MEMS device in the group. In addition, for any one of the groups, the added voltage used by one of the MEMS devices in the group may be the same as the added voltage used by another MEMS device in the group.

[0074] Fig. 7A and Figure 7BFigures 700a and 700b are shown respectively, which further illustrate the use of group-level voltages by a semiconductor chip with MEMS devices and built-in voltage generators according to some aspects of the present disclosure. For example, Figure 700a shows two MEMS devices 210a, 210b. In this example, the two MEMS devices 210a, 210b are part of the same group (see the common circle in the dashed line, which represents the same radius from the reference point). In addition, both MEMS devices 210a, 210b are microlenses with a single electrostatic element 215. As described above, for each group, there may be one or more local voltage generators 220 (not shown), so different MEMS devices can be in the same group to receive the same or different voltages. In this example, the voltage V1 applied to the MEMS device 210a can be the same or different from the voltage V2 applied to the MEMS device 210b. Although diagram 700a does not show a voltage generator, a group associated with both MEMS devices 210a, 210b may have: a single voltage generator 220 that provides the same voltage to both MEMS devices 210a, 210b; a single voltage generator 220 that provides different voltages to both MEMS devices 210a, 210b; two different voltage generators 220, one providing a voltage to MEMS device 210a and the other providing the same voltage to MEMS device 210b; or two different voltage generators 220, one providing a voltage to MEMS device 210a and the other providing a different voltage to MEMS device 210b. In each of these configurations, the applied voltage may be based on a primary voltage provided by a separate voltage generator through a floating ground for the group and a secondary voltage provided by a local voltage generator 220.

[0075] Diagram 700b shows two MEMS devices 210c, 210d. In this example, the two MEMS devices 210c, 210d are part of the same group (see the common circle in the dashed line, which indicates the same radius from the reference point). In addition, both MEMS devices 210c, 210d are micro-deflectors or stigmators with multiple electrostatic elements 215. As described above, there may be one or more local voltage generators 220 (not shown) for each group, so different MEMS devices can be in the same group to receive the same or different voltages. In this example, the voltages V1a, V1b, V1c, and V1d applied to the MEMS device 210c may be the same or different from the corresponding voltages V2a, V2b, V2c, and V2d applied to the MEMS device 210d. Although diagram 700b does not show a voltage generator, the group associated with both MEMS devices 210c, 210d may have a single voltage generator 220 that provides the same voltage to both MEMS devices 210c, 210d, a single voltage generator 220 that provides different voltages to both MEMS devices 210c, 210d, or multiple voltage generators 220 that provide the same or different voltages to both MEMS devices 210c, 210d. In each of these configurations, the applied voltage may be based on a primary voltage provided by a separate voltage generator through a floating ground for the group and a secondary voltage provided by the local voltage generator 220.

[0076] Combine the above Fig. 7A and Figure 7B The features described in FIG. 700a and FIG. 700b can be used in combination with one or more of the embodiments described above for a semiconductor chip (e.g., semiconductor chip 205). In addition, aspects of each of these embodiments can be combined to produce additional embodiments of a semiconductor chip.

[0077] The embodiments may be further described using the following terms:

[0078] 1. A semiconductor chip, comprising:

[0079] a plurality of micro-electromechanical systems (MEMS) devices;

[0080] a plurality of voltage generators, each of the voltage generators being configured to: generate a voltage for use by corresponding one or more of the MEMS devices; and

[0081] a plurality of electrical connections, each of the voltage generators being configured to provide a voltage to one or more MEMS devices through one or more of the electrical connections,

[0082] Each of the MEMS devices is configured to generate an electric field to manipulate an electron beamlet among a plurality of electron beamlets in a multi-beam charged particle microscope.

[0083] 2. The semiconductor chip according to clause 1, wherein the charged particle microscope comprises one of a scanning electron microscope (SEM), a scanning ion microscope, a transmission electron microscope (TEM), or a scanning proton microscope.

[0084] 3. The semiconductor chip according to clause 1, wherein each of the MEMS devices is a microlens, a microdeflector or an stigmator.

[0085] 4. The semiconductor chip according to clause 1, wherein the number of MEMS devices is equal to or greater than the number of voltage generators.

[0086] 5. The semiconductor chip according to clause 1, wherein the number of MEMS devices is less than the number of voltage generators.

[0087] 6. The semiconductor chip of clause 1, wherein each of the electrical connections comprises a plurality of conductive lines.

[0088] 7. The semiconductor chip of clause 1, wherein the MEMS devices are arranged into a plurality of subsets, the voltage generator comprises one voltage generator for each subset, and the one voltage generator is configured to generate a voltage for each of the MEMS devices in the respective subset.

[0089] 8. The semiconductor chip of clause 7, wherein one of the voltage generators is configured to provide a voltage to each of the MEMS devices in the respective subset through a separate one of the electrical connections.

[0090] 9. The semiconductor chip of clause 7, wherein each of the MEMS devices in the respective subset is a microlens having a single electrostatic element to which a voltage is applied.

[0091] 10. The semiconductor chip according to clause 7, wherein the number of MEMS devices in each subset is the same.

[0092] 11. The semiconductor chip according to clause 7, wherein the number of MEMS devices is different for different subsets.

[0093] 12. The semiconductor chip according to clause 7, wherein one of the voltage generators is located at the center of the MEMS devices in the respective subset.

[0094] 13. The semiconductor chip of clause 1, wherein the MEMS devices are arranged into a plurality of subsets, the voltage generator comprises one voltage generator for each subset, and the one voltage generator is configured to generate a plurality of voltages for each of the MEMS devices in the respective subset.

[0095] 14. The semiconductor chip of clause 13, wherein one of the voltage generators is configured to provide a plurality of voltages to each of the MEMS devices in the respective subset through a plurality of separate ones of the electrical connections.

[0096] 15. The semiconductor chip according to clause 13, wherein each of the MEMS devices in the corresponding subset is a micro-deflector or an stigmator having a plurality of electrostatic elements to which a plurality of voltages are respectively applied.

[0097] 16. The semiconductor chip according to clause 13, wherein the number of MEMS devices in each subset is the same.

[0098] 17. The semiconductor chip according to clause 13, wherein the number of MEMS devices in each subset is different for different subsets.

[0099] 18. The semiconductor chip according to clause 13, wherein one of the voltage generators is located at the center of the MEMS devices in the respective subset.

[0100] 19. The semiconductor chip according to clause 1 further includes a stack of layers arranged above the top surface of the semiconductor chip, the stack of layers being configured to: provide one or more power supplies to power the voltage generator through one or more power supply layers, and provide one or more ground planes connected to the voltage generator through one or more ground plane layers.

[0101] 20. The semiconductor chip according to clause 19, wherein the stack of layers further comprises a plurality of isolation layers to isolate one or more power supply layers and a ground plane layer from each other.

[0102] 21. The semiconductor chip according to clause 19, wherein the stack of layers has an opening, wherein the walls of the opening have a metal coating and are connected to a reference voltage or ground, and are configured to avoid or reduce charging effects due to accumulation of electrons or charged particles.

[0103] 22. The semiconductor chip according to clause 19, wherein each of the voltage generators is connected to one or more power supplies.

[0104] 23. The semiconductor chip according to clause 19, wherein each of the voltage generators is connected to one or more ground planes.

[0105] 24. The semiconductor chip according to clause 19, wherein each of the electrical connections connects the MEMS device to a respective voltage generator through the stack of layers.

[0106] 25. The semiconductor chip according to clause 1, wherein the MEMS device and the voltage generator are integrated in the semiconductor chip.

[0107] 26. The semiconductor chip according to clause 1, wherein the semiconductor chip is part of an image forming element configured to be used in a multi-beam SEM.

[0108] 27. A semiconductor chip, comprising:

[0109] a plurality of micro-electromechanical systems (MEMS) devices defining boundaries in a semiconductor chip;

[0110] a plurality of voltage generators located within the boundary, each of the voltage generators being configured to: generate a voltage for use by one or more of the MEMS devices; and

[0111] A plurality of electrical connections are located within the boundary, and each of the voltage generators is configured to provide a voltage to the one or more MEMS devices through one or more of the electrical connections.

[0112] 28. The semiconductor chip according to clause 27, wherein each of the MEMS devices is a microlens, a microdeflector or an stigmator.

[0113] 29. The semiconductor chip according to clause 27, wherein the number of MEMS devices is equal to or greater than the number of voltage generators.

[0114] 30. The semiconductor chip according to clause 27, wherein the number of MEMS devices is less than the number of voltage generators.

[0115] 31. The semiconductor chip of clause 27, wherein each of the electrical connections comprises a plurality of conductive lines.

[0116] 32. The semiconductor chip according to clause 27 further includes a stack of layers arranged above the top surface of the semiconductor chip, the stack of layers being configured to: provide one or more power supplies to power the voltage generator through one or more power supply layers, and provide one or more ground planes connected to the voltage generator through one or more ground plane layers.

[0117] 33. The semiconductor chip according to clause 27, wherein the semiconductor chip is part of an image forming element configured for use in a multi-beam charged particle microscope.

[0118] 34. The semiconductor chip according to clause 33, wherein the charged particle microscope comprises one of a scanning electron microscope (SEM), a scanning ion microscope, a transmission electron microscope (TEM), or a scanning proton microscope.

[0119] 35. A semiconductor chip, comprising:

[0120] a plurality of microelectromechanical system (MEMS) devices, each of the MEMS devices being part of one of a plurality of groups of MEMS devices, and each group being based on distances of the MEMS devices in the group to a reference location in the semiconductor chip;

[0121] a plurality of voltage generators, each of the voltage generators being configured to: generate a voltage for use by one or more of the MEMS devices; and

[0122] A plurality of electrical connections, each of the voltage generators being configured to provide a voltage to one or more MEMS devices through one or more of the electrical connections.

[0123] 36. The semiconductor chip according to clause 35, wherein each of the MEMS devices is configured to generate an electric field to manipulate a beamlet of a plurality of electron beamlets in a multi-beam charged particle microscope.

[0124] 37. The semiconductor chip according to clause 36, wherein the charged particle microscope comprises one of a scanning electron microscope (SEM), a scanning ion microscope, a transmission electron microscope (TEM), or a scanning proton microscope.

[0125] 38. The semiconductor chip of clause 35, wherein the MEMS device defines a boundary in the semiconductor chip, and the voltage generator and the electrical connection are located within the boundary.

[0126] 39. The semiconductor chip according to clause 35, wherein each of the MEMS devices is a microlens, a microdeflector or an stigmator.

[0127] 40. The semiconductor chip according to clause 35, wherein the number of MEMS devices is equal to or greater than the number of voltage generators.

[0128] 41. The semiconductor chip of clause 35, wherein the number of MEMS devices is less than the number of voltage generators.

[0129] 42. The semiconductor chip of clause 35, wherein each of the electrical connections comprises a plurality of conductive lines.

[0130] 43. The semiconductor chip according to clause 35, wherein the reference position is aligned with an optical axis of a multi-beam charged-particle microscope.

[0131] 44. A semiconductor chip according to clause 43, wherein the semiconductor chip is part of an image forming element configured for a multi-beam charged particle microscope, and the center of the grid formed by the MEMS device is aligned with the optical axis of the multi-beam charged particle microscope.

[0132] 45. The semiconductor chip according to clause 35, wherein the distances of the MEMS devices in one group to the reference locations in the semiconductor chip are different than the distances of the MEMS devices in the other group to the reference locations in the semiconductor chip.

[0133] 46. ​​The semiconductor chip of clause 35, wherein there are one or more voltage generators associated with each group of MEMS devices.

[0134] 47. A semiconductor chip, comprising:

[0135] a plurality of micro-electromechanical systems (MEMS) devices;

[0136] a plurality of voltage generators, each of the voltage generators being configured to generate a secondary voltage that is added to a primary voltage for that voltage generator, the primary voltage being provided by a separate voltage generator, and the added voltage being used by one or more of the MEMS devices; and

[0137] A plurality of electrical connections, each of the voltage generators being configured to provide a voltage to a MEMS device through one or more of the electrical connections.

[0138] 48. The semiconductor chip according to clause 47, wherein the secondary voltage is less than the primary voltage.

[0139] 49. The semiconductor chip according to clause 47, wherein the primary voltage is less than the secondary voltage.

[0140] 50. The semiconductor chip according to clause 47, wherein the separate voltage generator is an external voltage generator of the semiconductor chip.

[0141] 51. The semiconductor chip according to clause 47, wherein the separate voltage generator is built into the semiconductor chip.

[0142] 52. The semiconductor chip of clause 47, wherein each of the MEMS devices is part of one of a plurality of groups of MEMS devices, and each group is based on distances of the MEMS devices in the group to a reference location in the semiconductor chip.

[0143] 53. The semiconductor chip of clause 52, further comprising a separate floating ground for each group of MEMS devices, each group using the same primary voltage, and the primary voltage is provided by the floating ground for the group.

[0144] 54. The semiconductor chip according to clause 53, further comprising additional electrical connections to connect each of the floating grounds to a respective individual voltage generator.

[0145] 55. The semiconductor chip of clause 53, wherein a primary voltage applied to one floating ground and corresponding set of MEMS devices is different from a primary voltage applied to another floating ground and corresponding set of MEMS devices.

[0146] 56. A semiconductor chip according to clause 52, wherein each MEMS device in one of the groups is a microlens, a microdeflector or an stigmator having a plurality of electrostatic elements, and a voltage generator in the voltage generator associated with the group generates a plurality of voltages, which are respectively applied to the plurality of electrostatic elements of at least one MEMS device in the group.

[0147] 57. The semiconductor chip of clause 52, wherein for any one group, an added voltage used by one of the MEMS devices in the group is different from an added voltage used by another of the MEMS devices in the group.

[0148] 58. The semiconductor chip of clause 52, wherein for any one group, an added voltage used by one of the MEMS devices in the group is the same as an added voltage used by another of the MEMS devices in the group.

[0149] The present disclosure (which includes Figures 1A to 7B The present disclosure provides various techniques for improving the scalability of the number of electron beamlets used in a SEM system. For example, the present disclosure describes the use of built-in local voltage generators, which reduces the need for cumbersome connections and allows for a higher density of MEMS devices in an image forming element. In addition, the use of floating grounds for different groups of MEMS devices enables smaller local voltage generators, further enabling a higher density of MEMS devices in an image forming element, and thus a larger number of electron beamlets to achieve increased inspection throughput.

[0150] It should be understood that the described embodiments are not mutually exclusive, and elements, components, materials, or steps described in conjunction with one exemplary embodiment may be combined with or removed from other embodiments in a suitable manner to achieve desired design goals.

[0151] As used herein, unless specifically stated otherwise, the term "or" encompasses all possible combinations unless not feasible. For example, if it is stated that a component may include A or B, then unless otherwise explicitly stated or not feasible, the component may include A or B, or A and B. As a second example, if it is stated that a component may include A, B, or C, then unless otherwise explicitly stated or not feasible, the component may include A or B or C, or A and B, or A and C, or B and C, or A and B and C.

[0152] In addition, the articles "a" and "an" as used in this application and the appended claims should generally be construed to mean "one or more" unless specified otherwise or clear from context to be directed to a singular form.

[0153] The use of reference numerals or figure reference labels in the claims is intended to facilitate interpretation of the claims. Such use should not be interpreted as necessarily limiting the scope of those claims to the embodiments or implementations shown in the corresponding figures.

[0154] It will be further understood that persons skilled in the art may make various changes in the details, materials and arrangements of components described and shown to illustrate the nature of the described aspects or embodiments without departing from the scope expressed in the appended claims.

Claims

1. A semiconductor chip, comprising: multiple MEMS devices; a plurality of voltage generators, each of the voltage generators being configured to: generate a voltage used by corresponding one or more of the micro-electro-mechanical systems devices, wherein the voltage comprises a sum of a primary voltage and a secondary voltage; as well as a plurality of electrical connections, each of the voltage generators being configured to provide the voltage to the one or more MEMS devices via one or more of the electrical connections, Each of the MEMS devices is configured to generate an electric field to manipulate an electron beamlet in a plurality of electron beamlets in a multi-beam charged particle microscope. 2 . The semiconductor chip of claim 1 , wherein the charged particle microscope comprises one of a scanning electron microscope or a transmission electron microscope. 3 . The semiconductor chip according to claim 1 , wherein each of the MEMS devices is a microlens, a microdeflector, or an stigmator. 4 . The semiconductor chip according to claim 1 , wherein the number of the MEMS devices is equal to or greater than the number of the voltage generators. 5 . The semiconductor chip according to claim 1 , wherein the number of the MEMS devices is smaller than the number of the voltage generators. The semiconductor chip of claim 1 , wherein each of the electrical connections comprises a plurality of conductive lines.

7. The semiconductor chip of claim 1 , wherein the MEMS devices are arranged into a plurality of subsets, the voltage generator comprises one voltage generator for each subset, and the one voltage generator is configured to generate a voltage for each of the MEMS devices in the corresponding subset. 8 . The semiconductor chip of claim 7 , wherein the one voltage generator is configured to provide the voltage to each of the MEMS devices in the respective subset through a separate one of the electrical connections. 9 . The semiconductor chip of claim 7 , wherein each of the MEMS devices in the respective subset is a microlens having a single electrostatic element to which the voltage is applied.

10. The semiconductor chip of claim 7, wherein the number of MEMS devices in each subset is the same.

11. The semiconductor chip according to claim 7, wherein the number of MEMS devices is different for different subsets. 12 . The semiconductor chip according to claim 7 , wherein the one voltage generator is located at a center of the MEMS devices in the corresponding subset.

13. The semiconductor chip of claim 1 , wherein the MEMS devices are arranged into a plurality of subsets, the voltage generator comprises one voltage generator for each subset, and the one voltage generator is configured to generate a plurality of voltages for each of the MEMS devices in the corresponding subset. 14 . The semiconductor chip of claim 13 , wherein the one voltage generator is configured to provide the plurality of voltages to each of the MEMS devices in the respective subset through a plurality of separate ones of the electrical connections. 15 . The semiconductor chip according to claim 13 , wherein each of the MEMS devices in the corresponding subset is a micro deflector or an stigmator having a plurality of electrostatic elements to which the plurality of voltages are applied, respectively.

Images