Beam distribution measuring device and method of semiconductor beam equipment

Abstract

The invention discloses a beam distribution measuring device and method for semiconductor beam equipment, and belongs to the technical field of semiconductor beam measurement. The device comprises a vacuum displacement platform, a Faraday probe, a beam measurement electronics system and an upper computer. The vacuum displacement platform bears a collimating plate provided with a small flow collimating hole, and can perform high-precision scanning movement in a two-dimensional plane perpendicular to the beam direction; the Faraday probe is fixedly installed at the downstream of the displacement platform, a collecting pole plate of the Faraday probe directly faces the beam collimation small hole, a magnet array is arranged at the bottom of the collecting pole plate and is connected with a bias voltage circuit to form an electromagnetic dual secondary electron suppression structure, and a standby pole plate is used for detecting penetrating beams and triggering interlocking; the beam measurement electronics system comprises a beam measurement electronics board card and a CPCI case multi-channel acquisition board card; and the upper computer carries out data processing and beam spot inversion to obtain a beam distribution diagram. According to the invention, high-precision, high-signal-to-noise-ratio and multi-parameter online measurement of beam distribution in semiconductor ion implantation and etching equipment is realized.

Description

Technical Field

[0001] This application belongs to the field of beam measurement technology in semiconductor beam equipment such as ion implanters and ion beam etching machines, and specifically relates to a beam distribution measurement device and method for semiconductor beam equipment. Background Technology

[0002] Ion implantation and etching are key processes in the manufacturing of semiconductor devices. In ion implantation and some special etching processes, the required ion beam is generated by an ion source. The ion beam is accelerated by an accelerator or extracted by an electric field to perform ion implantation or etching on the surface of a silicon wafer or solid target.

[0003] With the development of semiconductor technology, the requirements for manufacturing processes and efficiency are increasing. More precise and effective beam distribution measurement methods are needed. The dosage injected into each chip or the surface etching process must be highly accurate and uniformly distributed. Inaccurate dosage can lead to device failure; poor uniformity can cause performance differences within and between chips, directly reducing yield. While ensuring dosage control and uniformity, it is also necessary to monitor the beam profile and stability. Abnormal beam shapes, such as hollow or asymmetrical beams, often indicate malfunctions in the ion source, extraction, or focusing system. Early diagnosis can prevent mass production accidents and guide preventative maintenance. Furthermore, to meet the specific needs of the semiconductor industry, beam measurement devices and corresponding measurement methods need to be developed and improved for the special operating conditions of different application scenarios. Summary of the Invention

[0004] In order to address the technical deficiencies of existing technologies, such as low spatial resolution, poor anti-interference ability, single function, and lack of real-time feedback, this application provides a beam distribution measurement device and method for semiconductor beam equipment, which realizes high-precision, high signal-to-noise ratio, and multi-parameter online measurement of beam distribution in semiconductor ion implantation and etching equipment.

[0005] The technical solution is as follows: On one hand, a beam distribution measurement device for a semiconductor beam apparatus is provided, comprising: A displacement platform is installed inside a vacuum chamber. A collimating plate is supported on the displacement platform. A beam collimation hole is opened in the middle of the collimating plate. The displacement platform is used to drive the collimating plate to scan and move in a two-dimensional plane perpendicular to the beam direction. A Faraday probe is fixedly installed downstream of the displacement platform. The Faraday probe includes a collecting electrode and a spare electrode located behind the collecting electrode. The collecting electrode faces the light-emitting side of the beam collimation aperture and is used to collect the beam signal passing through the beam collimation aperture and convert it into a current signal for output. The spare electrode is used to detect the beam signal passing through the collecting electrode and trigger an interlock. A magnet array is provided at the bottom of the collecting electrode for magnetic suppression of secondary electrons. The collecting electrode is connected to a bias voltage circuit for electrical suppression of secondary electrons. The beam measurement electronics system is electrically connected to the Faraday probe and the displacement platform, respectively. The beam measurement electronics system includes a beam measurement electronics board and a CPCI chassis multi-channel acquisition board. The beam measurement electronics board is used to receive the current signal. The CPCI chassis multi-channel acquisition board has built-in programmable logic devices for synchronously controlling the movement of the displacement platform, triggering the analog-to-digital converter to sample, and associating and storing the sampled data with position coordinates. The host computer communicates with the beam measurement electronics system to receive packaged data, execute beam spot inversion algorithms to reconstruct the two-dimensional distribution of the beam, and perform visualization display.

[0006] This application solves the common industry problems of low resolution, poor anti-interference, single function, and lack of real-time feedback in semiconductor beam measurement through a comprehensive technical solution of pinhole scanning, electromagnetic dual-suppression Faraday probe, beam measurement electronics system, and matrix inversion algorithm. It realizes high-precision, high signal-to-noise ratio, multi-parameter, and intelligent online measurement of beam distribution.

[0007] Employing a "small aperture scanning + matrix inversion" architecture, the beam is spatially confined using a 3mm aperture beam collimation aperture. Combined with a matrix inversion algorithm based on spatial mapping or a point spread function convolution fitting algorithm, an equivalent position resolution of ≤0.5mm can be achieved. This breaks through the physical limitations of traditional Faraday cup arrays, which are limited by the cup aperture and the arrangement spacing (usually ≥5mm). It can finely depict beam spot details and meet the stringent requirements of advanced processes for beam uniformity.

[0008] In a further technical solution, the collimating plate is a silicon carbide collimating plate, and its surface is coated with a dense coating by SiC-CVD process; the beam collimating aperture is a tapered through-hole structure, and the collimating plate is a detachable structure to replace beam collimating apertures of different diameters.

[0009] The displacement platform includes a vacuum motor motion structure and a grating ruler feedback unit. The vacuum motor motion structure leads out the grating and motor control wiring to the displacement platform controller.

[0010] The quasi-straight plate uses a silicon carbide substrate and forms a dense coating through the SiC-CVD process. Compared with traditional metal quasi-straight plates, its sputtering resistance life is increased by more than 3 times and there is no risk of metal contamination; the collection plate and the spare plate are made of molybdenum material with a lower sputtering yield (Mo < W < Fe < Al), which significantly delays the thinning and deformation of the plate caused by ion bombardment; the permanent magnet uses N52 neodymium iron boron with a high Curie temperature and is suitable for high-temperature vacuum environments; the signal transmission uses a low-noise double-layer shielded cable, which effectively suppresses radio frequency interference and motor commutation noise in the vacuum chamber. The overall design fully meets the requirements of 7×24-hour continuous operation of semiconductor production machines.

[0011] In a further technical solution, the magnet array is a permanent magnet with a checkerboard-like N / S pole staggered arrangement; the bias voltage circuit is used to apply an adjustable positive bias voltage of 0-100V to the collection plate.

[0012] In a further technical solution, the Faraday probe further includes: A shielding cover that covers the collection plate, the spare plate and the magnet array, and a silicon carbide baffle is fixed on the top of the shielding cover; Insulating support columns for achieving electrical isolation between the collection plate, the spare plate and the shielding cover.

[0013] The Faraday probe integrates an electromagnetic dual secondary electron suppression structure: a N52 neodymium iron boron permanent magnet array with a checkerboard-like N / S pole staggered arrangement is provided at the bottom of the collection plate, forming a strong magnetic field of ≥0.2T on the surface of the collection plate; at the same time, the collection plate is connected to a 0-100V adjustable positive bias voltage circuit, and the shielding cover is grounded to form an electric potential well. The synergistic effect of the magnetic field and the electric field can effectively constrain the trajectory of low-energy secondary electrons and prevent them from escaping, reducing the secondary electron escape rate by more than 90%, significantly improving the signal-to-noise ratio, and is especially suitable for high-precision measurements in low-energy beam current or high-sputtering yield scenarios.

[0014] In a further technical solution, the beam measurement electronics board integrates: A current-voltage conversion circuit, including a transimpedance amplification path and an integration amplification path, for realizing instantaneous beam current measurement or integrated dose measurement of the current signal according to the switching of the measurement mode; A bias voltage circuit for generating a bias voltage; An isolation operational amplifier and a second-order active low-pass filter circuit for isolating and suppressing noise of the voltage signal.

[0015] In a further technical solution, the beam measurement electronics board has three switchable measurement modes: Integrated measurement, switching to the integration amplification path, for integrating and amplifying the beam current under a fixed integration time for voltage-current conversion, and evaluating the beam dose with the charging voltage of the capacitor; The collection electrode measurement is switched to the transimpedance amplification path for real-time measurement of the instantaneous beam intensity output by the collection electrode; The backup electrode measurement is used to measure the instantaneous current intensity output by the backup electrode in real time. When the current signal exceeds a preset threshold, the CPCI chassis multi-channel acquisition board triggers an interlock and reports to the host computer.

[0016] The beam measurement electronics board integrates a reconfigurable current-to-voltage conversion circuit, supporting online switching of three measurement modes: an integrating amplification mode for evaluating beam integrated dose via the charging voltage of the integrating capacitor; a collector electrode measurement mode for real-time monitoring of instantaneous beam current intensity; and a backup electrode measurement mode for real-time monitoring of abnormal beam current penetrating the collector electrode and triggering hardware interlocks. A single device simultaneously provides dose monitoring, distribution measurement, and fault protection functions, eliminating the need for multiple independent devices and significantly reducing system complexity and cost.

[0017] A further technical solution is that the CPCI chassis multi-channel includes: The control processing module includes a field-programmable gate array (FPGA) chip; the FPGA chip is internally configured with an analog-to-digital converter (ADC) and a digital-to-analog converter (DAC). The data acquisition module is used for data processing and beam spot inversion.

[0018] The CPCI chassis multi-channel acquisition board, based on the ZYNQ series fully programmable system-on-a-chip, achieves sub-millisecond synchronization of 5MHz high-speed analog-to-digital conversion sampling and 0.1mm-level displacement platform closed-loop control, ensuring strict correspondence between sampled data and position coordinates. The host computer incorporates algorithms such as background subtraction, matrix inversion, and point spread function convolution fitting to automatically generate a two-dimensional beam density heatmap, X / Y direction profile curves, beam spot centroid coordinates, half-width at half-maximum (HWHM), and Gaussian fit goodness of fit. It also features multiple alarm and interlock functions for backup electrode signal over-limit, motor abnormality, and analog-to-digital conversion over-range, realizing a shift from "offline sampling inspection" to "real-time online monitoring and intelligent early warning."

[0019] A further technical solution is provided, wherein the host computer includes: The parameter configuration module is used to set the scanning range, sampling step size, motor speed, measurement mode, and bias voltage value. The data processing and inversion module is used to perform background subtraction, matrix inversion algorithm based on spatial mapping, or two-dimensional Gaussian convolution fitting algorithm based on point spread function to generate two-dimensional density heat map of the beam and X / Y direction profile curve. The feature calculation module is used to calculate the centroid coordinates, full width at half maximum (FWHM), and Gaussian fit goodness of fit of the beam spot. The alarm and interlock module is used to issue alarm commands and trigger interlocks when the backup plate signal exceeds the limit, the motor is abnormal, or the analog-to-digital conversion exceeds the range.

[0020] On the other hand, a method for measuring the beam distribution of a semiconductor beam apparatus is provided, applied to the aforementioned beam distribution measurement device of the semiconductor beam apparatus, comprising: The host computer sets the measurement parameters and sends them to the CPCI chassis multi-channel acquisition board. The CPCI chassis multi-channel acquisition board configures the motion trajectory of the displacement platform and the measurement mode of the beam measurement electronics board according to the parameters. The displacement platform is controlled to drive the collimation plate, so that the beam collimation aperture continuously scans along a preset path in the XY plane perpendicular to the beam propagation direction; The Faraday probe collects the beam signal passing through the aperture in real time, and the collecting plate outputs the current signal generated by the beam bombardment to the beam measurement electronics board via the low-noise transmission cable. The beam measurement electronics board performs current-to-voltage conversion, isolation amplification, filtering, and analog-to-digital conversion on the current signal according to the current measurement mode, generating digital sample values. The CPCI chassis multi-channel acquisition board synchronously executes the position closed-loop control of the displacement platform and the trigger sampling of the analog-to-digital converter within one scanning cycle. It associates the digital sampling value of each sampling point with its corresponding two-dimensional coordinates and stores it in the cache. After the scan is completed, it packages all the data and uploads it to the host computer. The host computer receives the packaged data, uses an inversion algorithm to solve for the beam intensity at each grid position within the measurement area, and reconstructs and displays a two-dimensional distribution map of the beam.

[0021] In a further technical solution, the inversion algorithm is a matrix inversion algorithm or a point spread function convolution fitting algorithm.

[0022] The technical solution includes at least the following technical effects: Specifically designed for ion beam distribution measurement in semiconductor equipment, including: two-dimensional beam distribution, beam profile, and integrated dose measurement, enabling rapid measurement of equipment beam parameters; The Faraday probe structure features both electrical suppression and permanent magnet suppression, and its physical design fully considers the specific requirements of applications in semiconductor scenarios. Dedicated beam measurement electronics boards and CPCI multi-channel acquisition boards enable synchronous sampling and high-precision processing of beam signals from the displacement platform; the CPCI chassis (CompactPCI chassis) integrates multi-channel acquisition boards, serving as the real-time control and data communication hub of the system.

[0023] The beam processing upper computer software algorithm is used to achieve high position resolution inversion by utilizing a large aperture.

[0024] It should be understood that the above general description and the following detailed description are merely exemplary and do not limit this application. Attached Figure Description

[0025] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with this application and, together with the description, serve to explain the principles of this application.

[0026] Figure 1 A structural diagram of a beam distribution measurement device for a semiconductor beam apparatus provided in a preferred embodiment of this application; Figure 2 This is a diagram of a preferred embodiment of the magnet array mounting structure provided in this application; Figure 3 This is a simulation result diagram of a magnet array provided in a preferred embodiment of this application; Figure 4 A structural diagram of a Faraday probe provided in a preferred embodiment of this application; Figure 5 A schematic diagram of a beam distribution measurement device for a semiconductor beam apparatus provided in a preferred embodiment of this application; Figure 6 This is a diagram showing the two-dimensional beam distribution measurement results provided in a preferred embodiment of this application; Explanation of reference numerals in the attached figures: 10. Displacement platform; 101. Collimation plate; 102. Beam collimation aperture; 20. Faraday probe; 201. Collecting electrode; 202. Spare electrode; 203. Shielding cover; 204. Grid; 205. Silicon carbide baffle; 206. Magnet mounting base plate; 207. Magnet; 208. Collecting electrode signal lead-out terminal; 209. Spare electrode signal lead-out terminal; 30. Beam measurement electronics system; 301. Beam measurement electronics board; 302. CPCI chassis multi-channel acquisition board; 40. Platform mounting bracket. Detailed Implementation

[0027] To make the objectives, technical solutions, and advantages of this application clearer, the following detailed description is provided in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the scope of this application.

[0028] In this document, the term "embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment mutually exclusive with other embodiments. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0029] Definitions: DDR3: Cache, used for temporary data storage.

[0030] PHY: Physical layer.

[0031] Ethernet: Ethernet network.

[0032] Faraday: The Faraday probe.

[0033] Bias: Bias voltage.

[0034] OP: Operational amplifier.

[0035] Isolated-OP: Isolated op-amp.

[0036] DAC: Digital-to-Analog Converter.

[0037] ADC: Analog-to-Digital Converter.

[0038] MFB: Second-order active low-pass filter circuit.

[0039] Charge Voltage: Integral measurement.

[0040] Beam Current: Measurement of collected plates.

[0041] Burn-thru: Spare plate measurement.

[0042] Strike plate: a plate used for collecting materials.

[0043] Burn-thru: Spare electrode plate.

[0044] Beam: Beam stream.

[0045] Example 1: A beam distribution measurement device for a semiconductor beam apparatus is provided, comprising: a Faraday probe, a displacement platform, a beam measurement electronics system, and a host computer.

[0046] A displacement platform is installed inside a vacuum chamber. A collimation plate is supported on the displacement platform. A beam collimation aperture is opened in the middle of the collimation plate. The displacement platform is used to drive the collimation plate to scan and move in a two-dimensional plane perpendicular to the beam direction.

[0047] A Faraday probe is fixedly installed downstream of the displacement platform. The Faraday probe includes a collecting electrode and a spare electrode located behind the collecting electrode. The collecting electrode faces the light-emitting side of the beam collimation aperture and is used to collect the beam signal passing through the beam collimation aperture and convert it into a current signal for output. The spare electrode is used to detect the beam signal passing through the collecting electrode and trigger an interlock. A magnet array is provided at the bottom of the collecting electrode for magnetic suppression of secondary electrons. The collecting electrode is connected to a bias voltage circuit for electrical suppression of secondary electrons.

[0048] The collimation plate is a silicon carbide collimation plate, and its surface is coated with a dense coating by SiC-CVD process; the beam collimation aperture is a tapered through-hole structure, and the collimation plate is a detachable structure to replace beam collimation apertures of different diameters.

[0049] The magnet array consists of permanent magnets with a checkerboard pattern of alternating N / S poles; the bias voltage circuit is used to apply an adjustable positive bias voltage of 0-100V to the collecting plate.

[0050] Faraday probes also include: A shielding cover is provided to enclose the collecting electrode plate, the spare electrode plate and the magnet array. A silicon carbide baffle is fixed to the top of the shielding cover. An insulating support column is used to achieve electrical isolation between the collecting electrode plate, the spare electrode plate, and the shielding cover.

[0051] The beam measurement electronics system is electrically connected to the Faraday probe and the displacement platform, respectively. The beam measurement electronics system includes a beam measurement electronics board and a CPCI chassis multi-channel acquisition board. The beam measurement electronics board is used to receive the current signal. The CPCI chassis multi-channel acquisition board has built-in programmable logic devices for synchronously controlling the movement of the displacement platform, triggering the analog-to-digital converter to sample, and associating and storing the sampled data with position coordinates. The beam measurement electronics board integrates: The current-to-voltage conversion circuit includes a transimpedance amplification path and an integral amplification path, used to realize instantaneous current intensity measurement or integral dose measurement of the current signal according to the measurement mode switching. Bias circuit, used to generate bias voltage; An isolation operational amplifier and a second-order active low-pass filter circuit are used for voltage signal isolation and noise suppression.

[0052] The beam measurement electronics board has three switchable measurement modes: Integral amplification measurement: switch to the integral amplification path to perform integral amplification of the beam at a fixed integration time for voltage-to-current conversion, and use the charging voltage of the capacitor to evaluate the beam dose; The collection electrode measurement is switched to the transimpedance amplification path for real-time measurement of the instantaneous beam intensity output by the collection electrode; The backup electrode measurement is used to measure the instantaneous current intensity output by the backup electrode in real time. When the current signal exceeds a preset threshold, the CPCI chassis multi-channel acquisition board triggers an interlock and reports to the host computer.

[0053] The CPCI chassis includes multiple channels: The control processing module includes a field-programmable gate array (FPGA) chip; the FPGA chip is internally configured with an analog-to-digital converter (ADC) and a digital-to-analog converter (DAC). The data acquisition module is used for data processing and beam spot inversion.

[0054] The host computer communicates with the beam measurement electronics system to receive packaged data, execute beam spot inversion algorithms to reconstruct the two-dimensional beam distribution, obtain the beam distribution map, and perform visualization display.

[0055] The host computer includes: The parameter configuration module is used to set the scanning range, sampling step size, motor speed, measurement mode, and bias voltage value. The data processing and inversion module is used to perform background subtraction, matrix inversion algorithm based on spatial mapping, or two-dimensional Gaussian convolution fitting algorithm based on point spread function to generate two-dimensional density heat map of the beam and X / Y direction profile curve. The feature calculation module is used to calculate the centroid coordinates, full width at half maximum (FWHM), and Gaussian fit goodness of fit of the beam spot. The alarm and interlock module is used to issue alarm commands and trigger interlocks when the backup plate signal exceeds the limit, the motor is abnormal, or the analog-to-digital conversion exceeds the range.

[0056] The principle is as follows: A beam collimator is installed on the displacement platform, with a conical aperture at its center to control the beam. It can move in a two-dimensional scan within a vacuum. A fixed beam collecting electrode is installed downstream of the beam to detect the weak signal emanating from the collimator. A permanent magnet array is installed at the bottom of the beam collecting electrode to magnetically suppress secondary electrons. The beam collecting electrode is suspended on a bias voltage, serving as an electrical suppression electrode for secondary electrons. A spare electrode is located behind the beam collecting electrode to detect the beam signal passing through it, triggering an interlock. The entire detector electrode assembly is enclosed within a protective cover to prevent interference from external stray beam signals. Within a measurement cycle, the collimating aperture performs a serpentine scanning motion of points within the measurement area via a displacement platform. The beam collecting plate collects the beam signal during the scanning process, and the current signal is input to the beam measurement electronics board. The beam measurement board includes a high-speed transimpedance / integrating amplifier circuit for current-to-voltage (IV) conversion, and can also perform bias setting, range switching, and measurement mode selection. The CPCI chassis multi-channel acquisition board synchronously completes the acquisition of beam measurement front-end signals, high-precision displacement platform control, data processing, and data uploading. Based on the acquired values ​​within the measurement cycle, the host computer software calculates the density cloud map of the two-dimensional beam distribution, thus enabling real-time measurement of parameters such as beam distribution and integrated dose.

[0057] like Figure 1 and Figure 5 As shown in the figure, this embodiment provides a beam distribution measurement device for a semiconductor beam apparatus, the function of which is to measure the two-dimensional distribution cross-section of the beam. The device mainly consists of three parts: a displacement platform 10, a Faraday probe 20, and a beam measurement electronics system 30. The components work together to complete the beam measurement within one cycle.

[0058] The displacement platform 10 includes a collimating plate, mounting components, and a vacuum motor motion structure; optionally, the collimating plate 101 is a silicon carbide collimating plate, and the vacuum motor is a displacement motor. Preferably, the displacement platform 10 is a precision displacement platform, which is a vacuum displacement platform.

[0059] A silicon collimator is fixedly mounted on the three-dimensional vacuum motor motion structure via mounting components. The silicon carbide collimator has a central collimator aperture, which is designed with a tapered through-hole structure to reduce the limitation of the collimator thickness on the beam measurement divergence angle. The silicon carbide collimator is detachable to allow replacement with beam collimators of different apertures.

[0060] The silicon carbide surface undergoes SiC-CVD treatment to ensure its density. It features a detachable structure, facilitating replacement with collimating holes of different materials and apertures. The displacement motor's motion structure leads out the grating and motor control wiring, which is connected to the displacement platform controller (e.g., ...). Figure 5As shown), the main control board performs motion control, with the displacement speed adjustable from 0-20 mm / s. During movement, it maintains a small vibration amplitude, with an overall displacement accuracy of less than 0.1 mm and a repeatability of less than 0.05 mm. The entire displacement platform 10 consists of a platform mounting bracket 40 (as shown). Figure 1 (As shown) It is fixedly installed in the vacuum chamber, and its displacement is calibrated by mechanical tooling before installation.

[0061] like Figure 4 As shown, a Faraday probe 20 is fixedly installed behind the vacuum displacement platform.

[0062] The Faraday probe 20 consists of a strike plate 201, a burn-thru 202, a magnet array, a shielding cover 203, and insulating support pillars. The strike plate 201 and the burn-thru 202 are selected based on the sputtering yield of the commonly used ion beam for etching / implantation. In this device, molybdenum is selected as the material for both the strike plate and the burn-thru. In terms of sputtering yield, Mo < W < Fe < Al, and molybdenum has a lower sputtering yield.

[0063] The collecting electrode 201 is installed facing the beam, and the spare electrode 202 is installed parallel to the rear of the collecting electrode. To suppress secondary electrons generated during beam bombardment of the electrode, a magnet array is arranged and installed behind the spare electrode 202 for magnetic suppression, and a bias voltage is applied to the collecting electrode for electrical suppression. Figure 2 As shown, the magnet array is fixedly mounted on the magnet 207 fixture in a checkerboard N / S alternating pattern. The magnets are N52 neodymium iron boron magnets. The magnetic field strength on the surface of the collecting plate is measured to be approximately 0.2T. The bias voltage is fed in by the signal acquisition cable and is adjustable from 0-100V.

[0064] Figure 3The simulation results of the magnet array show the distribution of the maximum and minimum peak magnetic field strength at different distances and their error ranges. The simulation data shows that within a measurement distance range of 0 to 375 mm, the maximum magnetic field peak value is stable between 0.20 and 1.05, and the minimum magnetic field peak value also shows a consistent distribution trend. Furthermore, the maximum and minimum peak value errors at each measurement point are controlled within 0.20 mm, with most points showing errors around 0.05 mm, indicating that the magnetic field generated by the magnet array has excellent uniformity and stability. Especially at longer distances (e.g., beyond 300 mm), the error value remains within 0.18 mm, verifying that the checkerboard-shaped N / S staggered N52 neodymium iron boron permanent magnet array can maintain a stable magnetic field strength distribution over a large spatial range. These simulation results fully demonstrate that the magnet array designed in this application can form a uniform and stable strong magnetic field region (≥0.2 T) on the surface of the collecting plate, providing a reliable magnetic field guarantee for effectively constraining the secondary electron trajectory and suppressing secondary electron escape, thereby significantly improving the signal-to-noise ratio and measurement accuracy of the Faraday probe.

[0065] like Figure 2 As shown, the magnet array is mounted on the magnet mounting base plate 206, and the collection electrode signal lead-out terminal 208 and the spare electrode signal lead-out terminal 209 are set on the magnet mounting base plate 206.

[0066] The collecting plate signal is at a high potential, while the shielding cover 203 and the vacuum chamber are at a low potential. Simion simulation results show that a voltage range of 50-100V is sufficient to suppress secondary electrons with an energy of 10eV.

[0067] like Figure 4 As shown, the collecting electrode 201, the spare electrode 202, and the magnet array are all installed inside the shielding cover 203. A grid 204 is arranged on one side, and a silicon carbide baffle 205 is fixedly installed on the top. The silicon carbide surface undergoes SiC-CVD treatment to ensure its surface density. The silicon carbide baffle 205 has a 105mm diameter hole in the center. The shielding cover 203 as a whole is used to reduce stray beam interference to the collecting electrode. The three components—collecting electrode 201, spare electrode 202, and shielding cover 203—are isolated from each other by insulating support pillars. Cables are led out from the bottom of the Faraday probe to connect the collecting electrode and the spare electrode to the vacuum feedthrough.

[0068] The beam measurement electronics system includes a beam measurement electronics board, a CPCI chassis multi-channel acquisition board, and control and data processing software. The beam measurement electronics board connects to signals from the vacuum feeder and processes the current signals obtained from the Faraday probe. The beam signal transmission cable is a low-noise transmission cable with a double-layer outer conductor shielding layer.

[0069] The beam measurement electronics board offers three measurement modes: Charge Voltage, Beam Current, and Burn-thru. In Charge Voltage mode, the beam current is integrated and amplified over a fixed integration time to achieve IV conversion, using the capacitor's charging voltage to assess the beam dose. The Beam Current and Burn-thru modes process the electrical signals from the Beam Current and Burn-thru electrodes, respectively. The beam current signal is suspended on a bias voltage, which is used to add the electrode bias voltage. The signal undergoes IV conversion via isolated transimpedance amplification. The acquisition board switches the transimpedance amplification range, and then the converted signal is isolated by an isolated operational amplifier (OPA). The voltage is amplified and filtered by a second-order active low-pass filter (MFB) before entering the ADC for acquisition. The beam measurement electronics board is designed with a bias voltage circuit to transmit and read back the 0-100V electrode voltage. The CPCI chassis multi-channel acquisition board is divided into data acquisition and control processing sections. The FPGA chip (Field Programmable Gate Array) is a ZYNQ series chip. It is configured with DAC (Digital-to-Analog Converter) and ADC (Analog-to-Digital Converter) to realize the control and acquisition of the beam measurement electronics board. The ADC sampling frequency is 5MHz. During a single scan measurement, the displacement platform is controlled and the ADC sampling is triggered at a specific position. The sampled data is filtered and stored using algorithms. After a measurement is completed, the entire data is packaged and uploaded. The data processing software section packages and uploads data from the CPCI chassis's multi-channel acquisition boards to the host computer. Specific algorithms are used for data processing and beam spot inversion, ultimately generating a two-dimensional heat map of the beam spot distribution, an X-direction profile, and a Y-direction profile for display. The software interface can perform real-time beam data reading, beam XY direction FWHM calculation, and Gaussian distribution fitting of the profile. It can also set and distribute parameters such as beam level, measurement range, motor speed, and sampling step. The software also has alarm functions including measurement over-range, backup electrode abnormality triggering interlock, and motor abnormality alarm.

[0070] like Figure 5 As shown, the displacement platform 10, in conjunction with the Faraday probe 20, completes the signal output of the collecting electrode 201 and the spare electrode 202. The beam direction is the z-axis direction, and the XY plane is the scanning plane. The two signals entering the beam measurement electronics board 30 can be used to select the measurement mode: ChargeVoltage is the integration measurement mode, BeamCurrent is the instantaneous beam current intensity measurement mode of the collecting electrode, and Burn-thru is the instantaneous current intensity measurement mode of the spare electrode. The CPCI chassis multi-channel acquisition board is the control processing and communication hub of the entire system, and can interact with the equipment via Ethernet.

[0071] Integral measurement channel (Charge Voltage) Integral amplification: Current charges a fixed capacitor, realizing the conversion of current to voltage, and the output voltage is proportional to the amount of charge; Integration time control: The integration time is controlled by ZYNQ to adapt to different beam intensities; Isolated-OP (isolation operational amplifier): provides electrical isolation to the integrated voltage signal, blocking ground loop interference; Differential amplification: converts single-ended signals into differential signals, improving the common-mode rejection ratio; MFB filter: Second-order active low-pass filter to remove high-frequency noise; Output to ADC: The conditioned analog voltage signal is sent to the analog-to-digital converter.

[0072] BeamCurrent (collecting plate measurement channel) / Burn-thru (spare plate measurement channel) Transimpedance amplification: Converts current signals directly into voltage signals through a feedback resistor for real-time monitoring of instantaneous current intensity; East-flow range control 1 / 2: By switching the feedback resistor value, multiple ranges can be automatically switched to adapt to different input current amplitudes; Differential amplification and MFB filtering: the same isolation, differential, and filtering processes as the integral measurement channel; Isolated-OP: Secondary isolation to ensure signal integrity; Output to ADC: The two signals are sent to the analog-to-digital converter respectively.

[0073] ADC (Analog-to-Digital Converter): Synchronously converts two conditioned analog voltage signals into digital quantities.

[0074] ZYNQ Control and Data Processing: The ZYNQ series chips serve as the core of the board, integrating FPGA logic and an ARM processor. The functions of the ZYNQ series chips include: receiving and parsing parameter configurations from the host computer; generating displacement platform control signals (forwarded via CPCI chassis 302); receiving trigger sampling commands and controlling the ADC sampling timing; reading ADC sampling data and associating it with position coordinates; caching data via DDR3; and communicating with the host computer via Ethernet.

[0075] DAC (Digital-to-Analog Converter): Converts the digital control input of ZYNQ into analog voltage.

[0076] ZYNQ sends motion commands to the displacement platform 10 via CPCI chassis 302; the grating ruler of the displacement platform feeds back position information, which is transmitted back to ZYNQ via CPCI chassis to achieve closed-loop control; when the platform moves to the preset sampling point, ZYNQ sends a trigger sampling signal to the ADC to ensure that the sampling point is strictly synchronized with the position.

[0077] Data flow and communication: Uplink (parameter distribution): Host computer software → Ethernet PHY → ZYNQ → Parse configuration parameters → DAC / Bias enable / gear switching / displacement platform control.

[0078] Downlink (data upload): ADC sampling data → ZYNQ (associated position coordinates) → DDR3 cache → Ethernet → host computer.

[0079] Packaged Upload: After a scan is completed, ZYNQ packages all "location-current intensity" data pairs and uploads them to the host computer via Ethernet; The host computer executes software processing and interface display (background subtraction, inversion algorithm, heat map generation, feature calculation, alarm interlock).

[0080] Measurement principle and procedure of two-dimensional beam distribution: The entire beam distribution measurement process is automated. Before the measurement begins, the corresponding measurement range is set, the maximum motor stroke is 100mm×100mm, the maximum motor speed is 20mm / s, and the minimum sampling step size is 0.1mm. During calibration, the theoretical beam center is used as the coordinate origin. The actual configurable measurement range is [-50mm, +50mm]. During the measurement process, a large scanning range and a large sampling step size are first selected to scan the beam spot to find the beam center position and approximate size. After calibrating the position, a small scanning range and a small sampling step size are selected to scan the beam spot to obtain a more detailed beam distribution map.

[0081] During the scanning process, the beam bombards the collimator plate on the displacement platform. The aperture of the collimator plate is 3mm in diameter, and the size of the collimator plate is much larger than the beam spot size. During the scanning process, only the beam signal of the aperture portion can be collected by the Faraday probe through the collimator plate. The movement of the collimator plate is a continuous motion, and the scanning path is a serpentine scanning path on the XY plane. Data is sampled according to the sampling step size.

[0082] s 11 a1+s 12 a2+…+s 1n a n =I1 s 21 a1+s 22 a2+…+s 2n a n =I2 ... s n1 a1+s n2 a2+…+s nn a n =I n Data processing: The obtained measurement data is in matrix form. The background current intensity obtained under no-beam current conditions is subtracted. The XY measurement plane is divided into 0-n grids. During the scanning process, the mapping area of ​​the aperture in each grid is s. ii a n To obtain the desired grid-averaged beam intensity, I1-I is obtained by stepping through n samples in n grids. n The current intensity value can be obtained by solving the matrix equation to get the a value for each grid. n By solving this matrix equation multiple times in different scanning areas, the two-dimensional beam distribution within the scanning area can be obtained. The beam intensity values ​​obtained by this algorithm for each beam distribution are closer to the actual beam values. Alternatively, the beam matrix data can be directly processed using a two-dimensional Gaussian fitting method in convolution form. The beam image obtained from the actual scan is a convolution of the real signal and the point spread function (PSF). This algorithm is a more advanced fitting method based on the physical imaging model. It can more accurately infer the true properties of the original signal from the observation data distorted by the system, making it more convenient for applications that only measure the beam distribution.

[0083] Figure 6 This is a diagram of the measurement result software interface provided in this application embodiment. The interface consists of three core display areas and a parameter setting area. The two-dimensional beam distribution heatmap in the upper left corner visually presents the beam intensity distribution in the XY plane using varying color shades. The approximately circular isointense lines in the diagram indicate good beam symmetry, with the center located near the origin of the coordinate system. There are no hollow areas, tails, or elliptical distortions, confirming that the ion source and extraction system are functioning normally. The lower left and lower right corners show the beam cross-sectional distribution curves in the X and Y directions, respectively. Both curves exhibit a typical Gaussian distribution, are smooth without burrs, and have a background close to zero, reflecting the measurement system's high signal-to-noise ratio and excellent secondary electron suppression effect. The half-width at half-maximum (WHM) of the two curves are basically the same, approximately 20 mm, further verifying the beam spot rotational symmetry. The parameter setting area in the upper right corner displays the current motor speed as 15.0 mm / s, and the set value is completely consistent with the feedback value, indicating high accuracy and stable response of the displacement platform closed-loop control. In summary… Figure 6 This fully verifies that the present application can accurately reconstruct a high signal-to-noise ratio and high symmetry beam two-dimensional distribution through electromagnetic dual suppression structure, pinhole scanning combined with matrix inversion algorithm and high-precision motion control, providing a reliable technical means for beam monitoring in semiconductor processes.

[0084] Example 2: A method for measuring beam distribution in a semiconductor beam apparatus is provided, comprising: The host computer sets the measurement parameters and sends them to the CPCI chassis multi-channel acquisition board. The CPCI chassis multi-channel acquisition board configures the motion trajectory of the displacement platform and the measurement mode of the beam measurement electronics board according to the parameters. The displacement platform is controlled to drive the collimation plate, so that the beam collimation aperture continuously scans along a preset path in the XY plane perpendicular to the beam propagation direction; The Faraday probe collects the beam signal passing through the aperture in real time, and the collecting plate outputs the current signal generated by the beam bombardment to the beam measurement electronics board via the low-noise transmission cable. The beam measurement electronics board performs current-to-voltage conversion, isolation amplification, filtering, and analog-to-digital conversion on the current signal according to the current measurement mode, generating digital sample values. The CPCI chassis multi-channel acquisition board synchronously executes the position closed-loop control of the displacement platform and the trigger sampling of the analog-to-digital converter within one scanning cycle. It associates the digital sampling value of each sampling point with its corresponding two-dimensional coordinates and stores it in the cache. After the scan is completed, it packages all the data and uploads it to the host computer. The host computer receives the packaged data, uses an inversion algorithm to solve for the beam intensity at each grid location within the measurement area, and reconstructs and displays a two-dimensional distribution map of the beam. Optionally, the inversion algorithm is a matrix inversion algorithm or a point spread function convolution fitting algorithm.

[0085] This application has the following technical advantages compared with the prior art: First, in terms of measurement principle, this application breaks through the limitations of traditional technology that relies on fixed probe arrays and whose spatial resolution is limited by the physical size of the probe (usually ≥5mm). It innovatively adopts a pinhole scanning and matrix inversion architecture. A high-precision displacement platform drives a SiC collimator plate with a conical pinhole to scan in a two-dimensional plane. Combined with matrix inversion or point spread function convolution fitting algorithm, it achieves an equivalent position resolution capability of ≤0.5mm and reconstruction of the two-dimensional distribution of the beam. In contrast, CN108008441A, a beam current intensity calibration and measurement system and method, can only measure the total current intensity and has no spatial resolution capability at all.

[0086] Secondly, in terms of signal fidelity, the Faraday probe of this application integrates a checkerboard-shaped N / S pole alternating permanent magnet array and a 0-100V adjustable positive bias voltage to form an electromagnetic dual secondary electron suppression structure, which can reduce the secondary electron escape rate by more than 90% and significantly improve the signal-to-noise ratio. In contrast, existing technologies do not involve secondary electron suppression design, and the measurement accuracy is limited in low-energy beam current or high sputtering scenarios.

[0087] Furthermore, in terms of functional integration and real-time performance, the beam measurement electronics system of this application supports online switching between three modes: integral measurement, instantaneous current intensity measurement, and backup electrode interlock. It also achieves sub-millisecond synchronization of displacement platform closed-loop control and analog-to-digital conversion sampling through FPGA, and has real-time alarm and interlock functions. This realizes the leap from "offline sampling inspection" to "real-time online monitoring and intelligent early warning". In contrast, although CN119126188A, a control system for accelerator beam measurement and diagnosis, is based on the EPICS architecture and has certain distributed control capabilities, its functions are relatively dispersed. CN108008441A, a beam current intensity calibration and measurement system and method, lacks real-time synchronization and control mechanisms.

[0088] Finally, in terms of the compatibility of materials and processes with semiconductor processes, this application uses SiC collimating plates, molybdenum electrodes and N52 neodymium iron boron permanent magnets treated with SiC-CVD dense coating, which effectively avoids the risk of metal contamination, significantly improves the lifespan and stability of the equipment in a vacuum environment, and better meets the stringent requirements of 7×24-hour continuous operation of semiconductor mass production lines.

[0089] In summary, this application surpasses existing technologies in terms of measurement resolution, anti-interference capability, functional integration, real-time control, and semiconductor process compatibility.

[0090] Although preferred embodiments of this application have been described, those skilled in the art, upon learning the basic inventive concept, can make other changes and modifications to these embodiments. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments as well as all changes and modifications falling within the scope of this application.

Claims

1. A beam distribution measurement device for a semiconductor beam apparatus, characterized in that, include: A displacement platform is installed inside a vacuum chamber. A collimating plate is supported on the displacement platform. A beam collimation hole is opened in the middle of the collimating plate. The displacement platform is used to drive the collimating plate to scan and move in a two-dimensional plane perpendicular to the beam direction. A Faraday probe is fixedly installed downstream of the displacement platform. The Faraday probe includes a collecting electrode and a spare electrode located behind the collecting electrode. The collecting electrode faces the light-emitting side of the beam collimation aperture and is used to collect the beam signal passing through the beam collimation aperture and convert it into a current signal for output. The spare electrode is used to detect the beam signal passing through the collecting electrode and trigger an interlock. A magnet array is provided at the bottom of the collecting electrode for magnetic suppression of secondary electrons. The collecting electrode is connected to a bias voltage circuit for electrical suppression of secondary electrons. The beam measurement electronics system is electrically connected to the Faraday probe and the displacement platform, and includes a beam measurement electronics board and a CPCI chassis multi-channel acquisition board; the beam measurement electronics board is used to receive the current signal. The CPCI chassis multi-channel acquisition board has built-in programmable logic devices for synchronously controlling the movement of the displacement platform, triggering analog-to-digital converter sampling, and associating and storing the sampled data with position coordinates and packaging it. The host computer communicates with the beam measurement electronics system to receive packaged data, execute beam spot inversion algorithms to reconstruct the two-dimensional distribution of the beam, and perform visualization display.

2. The beam distribution measurement device for semiconductor beam equipment according to claim 1, characterized in that, The collimation plate is a silicon carbide collimation plate, and its surface is coated with a dense coating by SiC-CVD process; the beam collimation aperture is a tapered through-hole structure, and the collimation plate is a detachable structure to replace beam collimation apertures of different diameters.

3. The beam distribution measurement device for semiconductor beam equipment according to claim 1, characterized in that, The magnet array is a permanent magnet with a checkerboard pattern of alternating N / S poles; the bias voltage circuit is used to apply an adjustable positive bias voltage of 0-100V to the collecting plate.

4. The beam distribution measurement device for semiconductor beam equipment according to claim 1, characterized in that, The Faraday probe also includes: A shielding cover is provided to enclose the collecting electrode plate, the spare electrode plate and the magnet array. A silicon carbide baffle is fixed to the top of the shielding cover. An insulating support column is used to achieve electrical isolation between the collecting electrode plate, the spare electrode plate, and the shielding cover.

5. The beam distribution measurement device for semiconductor beam equipment according to claim 1, characterized in that, The beam measurement electronics board integrates: The current-to-voltage conversion circuit includes a transimpedance amplification path and an integral amplification path, used to realize instantaneous current intensity measurement or integral dose measurement of the current signal according to the measurement mode switching. Bias circuit, used to generate bias voltage; An isolation operational amplifier and a second-order active low-pass filter circuit are used for voltage signal isolation and noise suppression.

6. The beam distribution measurement device for semiconductor beam equipment according to claim 5, characterized in that, The beam measurement electronics board has three switchable measurement modes: Integration measurement, switching to the integration amplification path, is used to integrate and amplify the beam current at a fixed integration time to perform voltage-to-current conversion, and the charging voltage of the capacitor is used to evaluate the beam dose; The collection electrode measurement is switched to the transimpedance amplification path for real-time measurement of the instantaneous beam intensity output by the collection electrode; The backup electrode measurement is used to measure the instantaneous current intensity output by the backup electrode in real time. When the current signal exceeds a preset threshold, the CPCI chassis multi-channel acquisition board triggers an interlock and reports to the host computer.

7. The beam distribution measurement device for semiconductor beam equipment according to claim 1, characterized in that, The CPCI chassis includes multiple channels: The control processing module includes a field-programmable gate array (FPGA) chip; the FPGA chip is internally configured with an analog-to-digital converter (ADC) and a digital-to-analog converter (DAC). The data acquisition module is used for data processing and beam spot inversion.

8. The beam distribution measurement device for semiconductor beam equipment according to claim 1, characterized in that, The host computer includes: The parameter configuration module is used to set the scanning range, sampling step size, motor speed, measurement mode, and bias voltage value. The data processing and inversion module is used to perform background subtraction, matrix inversion algorithm based on spatial mapping, or two-dimensional Gaussian convolution fitting algorithm based on point spread function to generate two-dimensional density heat map of the beam and X / Y direction profile curve. The feature calculation module is used to calculate the centroid coordinates, full width at half maximum (FWHM), and Gaussian fit goodness of fit of the beam spot. The alarm and interlock module is used to issue alarm commands and trigger interlocks when the backup plate signal exceeds the limit, the motor is abnormal, or the analog-to-digital conversion exceeds the range.

9. A method for measuring beam current distribution in a semiconductor beam apparatus, comprising using the beam current distribution measuring device for a semiconductor beam apparatus as described in any one of claims 1 to 8, characterized in that, include: The host computer sets the measurement parameters and sends them to the CPCI chassis multi-channel acquisition board. The CPCI chassis multi-channel acquisition board configures the motion trajectory of the displacement platform and the measurement mode of the beam measurement electronics board according to the parameters. The displacement platform is controlled to drive the collimation plate, so that the beam collimation aperture continuously scans along a preset path in the XY plane perpendicular to the beam propagation direction; The Faraday probe collects the beam signal passing through the beam collimation aperture in real time, and the collecting electrode outputs the current signal generated by the beam bombardment to the beam measurement electronics board via a low-noise transmission cable. The beam measurement electronics board performs current-to-voltage conversion, isolation amplification, filtering, and analog-to-digital conversion on the current signal according to the current measurement mode, generating digital sample values. The CPCI chassis multi-channel acquisition board synchronously executes the position closed-loop control of the displacement platform and the trigger sampling of the analog-to-digital converter within one scanning cycle. It associates the digital sampling value of each sampling point with its corresponding two-dimensional coordinates and stores it in the cache. After the scan is completed, it packages all the data and uploads it to the host computer. The host computer receives the packaged data, uses an inversion algorithm to solve for the beam intensity at each grid position within the measurement area, and reconstructs and displays a two-dimensional distribution map of the beam.

10. The beam distribution measurement method of the semiconductor beam apparatus according to claim 9, characterized in that, The inversion algorithm is either a matrix inversion algorithm or a point spread function convolution fitting algorithm.

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