Nanoscale plane parallel calibration and adjustment method

Abstract

The invention discloses a nanoscale plane parallel calibration and adjustment method, and relates to the technical field of micro-nano manufacturing. The method comprises the following steps: step 1, initializing a plane parallel calibration sensor and a plane distance measurement adjustment sensor; 2, carrying out plane distance measurement adjustment by using a plane distance measurement adjustment sensor; step 3, performing plane parallel calibration by using a plane parallel calibration sensor; and 4, replacing the sample, and performing plane scanning / etching after real-time adjustment. Measurement modes required by calibration and adjustment are isolated, plane parallel calibration is performed by using tunneling current measurement, plane distance measurement and adjustment are performed by using a superposed laser interferometer, and the method has the advantages of high stability, high scene adaptability, usability and low cost.

Description

A nanoscale planar parallel calibration and adjustment method Technical Field

[0001] This invention relates to the field of micro- and nano-manufacturing technology, and in particular to a method for nanoscale planar parallel calibration and adjustment. Background Technology

[0002] The development of industries such as semiconductors and atomic-level manufacturing has placed higher demands on high-throughput, agile manufacturing at extremely small scales (nanometers and even sub-nanometers). Direct-write manufacturing technologies based on near-field forces, such as tip electron beams, atomic force probes, and surface plasmons, meet these demands with their high resolution and manufacturing flexibility. However, conventional single-point serial manufacturing methods have room for improvement in throughput. Therefore, massively parallel manufacturing technologies, namely multi-beam, multi-probe parallel manufacturing, have emerged.

[0003] However, parallelization introduces a core challenge: ensuring precise and uniform parallel alignment and spacing control between the tool array plane and the sample surface at the nanoscale. Parallelism calibration, encompassing global spacing control, tilt / wedge error correction, and dynamic leveling, has become a critical bottleneck determining process yield, resolution, and equipment efficiency.

[0004] Currently, the mainstream metrological methods commonly used in the industry for parallelism calibration include optical triangulation, interferometry, and capacitance sensing.

[0005] Optical triangulation is a core technology in modern lithography focusing / leveling systems. Its working principle involves projecting a probe beam onto the wafer surface at an angle, then the imaging system receives the reflected light and images it onto a position-sensitive detector (such as a CCD or CMOS). Despite its widespread application, optical triangulation still faces many limitations. First, measurement accuracy is highly sensitive to the optical properties of the wafer surface and heavily dependent on the processing technology and substrate. Lithography requires a high-vacuum environment, which presents significant challenges in heat dissipation and contamination prevention for the optical components of the focusing and leveling system. The heat generated by the light source and detector operating in a vacuum is difficult to dissipate, leading to problems such as system performance drift.

[0006] When the accuracy requirement reaches the nanometer or even sub-nanometer level, interferometry based on the wave nature of light becomes the preferred method. When used as a gap sensor, by analyzing the phase of the interference pattern rather than its intensity or frequency, its detection algorithm can distinguish phase periods of less than one-thousandth, thus achieving extremely high measurement sensitivity. However, when used for high-precision collimation interferometry calibration, it has stringent usage requirements and limitations: (1) It requires ultra-stable environmental control, including constant temperature and humidity, low vibration environment, and dust-free clean space. (2) It requires strict beam collimation calibration and stability assurance of the reference mirror. (3) Its dynamic measurement capability is limited, including a sharp drop in accuracy under vibration and slow speed of dynamic compensation algorithm. In particular, the calibration process is a dynamic and iterative fine adjustment process, and the cumulative effect of thermal expansion and frequency drift that occur during long-term use of interferometry can cause calibration failure.

[0007] Another widely used method in semiconductor devices is capacitive sensing, which is a high-resolution, non-contact electronic measurement method with excellent vacuum compatibility and extremely high sensitivity. By measuring minute changes in capacitance through high-precision circuitry, the system can deduce the change in distance between the probe and the target surface. Despite the superior performance of capacitive sensors, their limitations must be carefully considered in practical applications: (1) Standard capacitive sensors require the target to be conductive, which imposes significant material limitations. (2) Displacement caused by mechanical vibration or thermal expansion and contraction of the sensor and its mounting fixture is indistinguishable from the actual displacement of the target surface in measurement, making mechanical and thermal instability crucial. (3) Installation errors, such as the parallelism between the sensor probe and the measured surface, are also key sources of error.

[0008] Based on the above methods, the commonly used horizontal plane calibration methods in the industry currently have the following three limitations: (1) Errors in mechanics, installation, clamping, etc., cannot be measured and eliminated, and are not applicable when there is a need for high resolution or when the spacing is very close (sub-100 nanometers). (2) The sensor has relatively harsh environmental requirements and will generate temperature drift after long-term (>5 min) use, affecting the measurement accuracy. (3) The sensor has requirements on the material properties of the object being detected and is dependent on the application scenario. Summary of the Invention

[0009] In view of the above-mentioned deficiencies of the prior art, the technical problem to be solved by the present invention is how to achieve calibration and parallel adjustment of the processing / scanning tool array surface and the sample surface at ultra-close distance (≤100nm) during semiconductor micro / nano processing / scanning.

[0010] To achieve the above objectives, this invention provides a cross-nanoscale planar parallel calibration and adjustment method, comprising the following steps: Step 1, initializing the planar parallel calibration sensor and the planar ranging adjustment sensor; Step 2, using the planar ranging adjustment sensor to perform planar ranging adjustment; Step 3, using the planar parallel calibration sensor to perform planar parallel calibration; Step 4, replacing the sample, adjusting in real time, and then performing planar scanning / etching.

[0011] Furthermore, the planar parallel calibration sensor is a sensor capable of generating tunneling current, and the planar ranging adjustment sensor is a sensor capable of quickly extracting the side distance between two planes.

[0012] Furthermore, the number of planar parallel calibration sensors is 3, and the number of planar ranging adjustment sensors is 3.

[0013] Furthermore, the planar parallel calibration sensor is a parallel light interferometer, and the planar distance adjustment sensor is a conductive probe.

[0014] Furthermore, the data from the parallel light interferometer and the current data from the conductive probe are saved into the signal database in real time.

[0015] Furthermore, the conductive probe material is platinum-iridium.

[0016] Furthermore, the ranging adjustment of the planar ranging adjustment sensor includes the macro mode of the macro stage and the micro mode of the micro stage.

[0017] Furthermore, the macro-motion mode has micrometer-level motion speeds in the x, y, and z directions, while the micro-motion mode has nanometer-level motion speeds in the x, y, z, and θx / θy angle directions.

[0018] Furthermore, the horizontal angles θx / θy are adjusted in real time using a MIMO feedback controller to detect whether the three conductive probes simultaneously generate tunneling current signals.

[0019] Furthermore, the objective lens monitoring data of the parallel light interferometer, the position data of the macro stage, and the position and angle data of the micro stage are saved into the signal and motion database in real time.

[0020] Compared with the prior art, the present invention has the following advantages: (1) The present invention cleverly solves the calibration problem in mechanical / industrial fields through the phenomenon of quantum mechanics, and is a model of interdisciplinary research; it can promote the MEMS processing technology of three conductive probes, make it mature and become a widely used calibration tool; the low-cost three-probe calibration method can reduce the mechanical complexity of parallel manufacturing equipment, and remove a core obstacle to industrial development.

[0021] (2) The present invention addresses calibration stability from a material perspective, a solution that is difficult for industry professionals to conceive of; it can reduce the manufacturing cost of equipment requiring calibration and provide a new solution for the industry.

[0022] (3) The present invention has a wide range of applications and can be used for the calibration and adjustment of planar horizontal plates in the range of tens of micrometers to sub-hundred nanometers, providing more solutions for the industry.

[0023] The following will further explain the concept, specific structure, and technical effects of the present invention in conjunction with the accompanying drawings, so as to fully understand the purpose, features, and effects of the present invention. Attached Figure Description

[0024] Figure 1 is a schematic diagram of the nanoscale planar parallel calibration and adjustment method according to an embodiment of the present invention. Detailed Implementation

[0025] The preferred embodiments of the present invention are described below with reference to the accompanying drawings to make the technical content clearer and easier to understand. The present invention can be embodied in many different forms, and the scope of protection of the present invention is not limited to the embodiments mentioned herein.

[0026] In the accompanying drawings, components with the same structure are indicated by the same numerical designation, and components with similar structures or functions are indicated by similar numerical designations. The dimensions and thicknesses of each component shown in the drawings are arbitrary, and the present invention does not limit the dimensions and thicknesses of each component. To make the illustrations clearer, the thickness of some components has been appropriately exaggerated in the drawings.

[0027] Currently, commonly used horizontal plane calibration methods in the industry have the following problems: At sub-100 nanometer pitches, any mechanical error and the inherent noise error of the measurement sensor cannot be ignored; accurate calibration before measurement is the core foundation for determining whether these errors can be compensated for. Existing sensors suffer from temperature drift due to heat generation during use, typically requiring very harsh environments (vacuum chamber / liquid nitrogen / liquid helium) to ensure sensor accuracy. Existing sensors have requirements for the materials of the calibration plane, such as conductive interfaces (capacitive sensors) / high-reflectivity planar coatings (interferometers), etc.

[0028] To address the aforementioned issues, this invention proposes a nanoscale planar parallel calibration and adjustment method. This method isolates the measurement methods required for calibration and adjustment, using tunneling current measurement for parallel calibration. This demonstrates the advantages of high stability, high adaptability to various scenarios, ease of use, and low cost. Furthermore, by superimposing a laser interferometer for distance adjustment measurements on this method, the solution can adapt to the needs of the semiconductor industry's development and possesses broad industrialization prospects.

[0029] This invention provides a cross-nanoscale planar parallel calibration and adjustment method, comprising the following steps: Step 1, initializing the planar parallel calibration sensor and the planar ranging adjustment sensor; Step 2, using the planar ranging adjustment sensor to perform planar ranging adjustment; Step 3, using the planar parallel calibration sensor to perform planar parallel calibration; Step 4, replacing the sample, adjusting in real time, and then performing planar scanning / etching.

[0030] Furthermore, the planar parallel calibration sensor is a sensor capable of generating tunneling current, and the planar ranging adjustment sensor is a sensor capable of quickly extracting the side distance between two planes.

[0031] Furthermore, the number of planar parallel calibration sensors is 3, and the number of planar ranging adjustment sensors is 3.

[0032] Furthermore, the planar parallel calibration sensor is a parallel light interferometer, and the planar distance adjustment sensor is a conductive probe.

[0033] Furthermore, the data from the parallel light interferometer and the current data from the conductive probe are saved into the signal database in real time.

[0034] Furthermore, the conductive probe material is platinum-iridium.

[0035] Furthermore, the ranging adjustment of the planar ranging adjustment sensor includes the macro mode of the macro stage and the micro mode of the micro stage.

[0036] Furthermore, the macro-motion mode has micrometer-level motion speeds in the x, y, and z directions, while the micro-motion mode has nanometer-level motion speeds in the x, y, z, and θx / θy angle directions.

[0037] Furthermore, the horizontal angles θx / θy are adjusted in real time using a MIMO feedback controller to detect whether the three conductive probes simultaneously generate tunneling current signals.

[0038] Furthermore, the objective lens monitoring data of the parallel light interferometer, the position data of the macro stage, and the position and angle data of the micro stage are saved into the signal and motion database in real time.

[0039] The implementation and realization of the technical solution of the present invention will be further described below through specific embodiments. It should be noted that the implementation and realization of the technical solution of the present invention are not limited to the following embodiments.

[0040] As shown in Figure 1, the present invention provides a nanoscale planar parallel calibration and adjustment method, which includes the following steps: Step 1: Initialize the planar parallel calibration sensor and the planar ranging adjustment sensor (1) Initialize the three-way parallel light interferometer (the planar ranging adjustment sensor includes, but is not limited to, other ranging sensors that can measure distances at three points to achieve planar parallel adjustment), and connect the conductive circuits of the three conductive probes (the planar parallel calibration sensor is not limited to the probe material; any common conductive probe that can generate tunneling current can be used).

[0041] (2) The data from the parallel light interferometer and the current data from the conductive probe are saved into the signal database in real time.

[0042] Step 2: Adjust the plane distance measurement using the plane distance measurement adjustment sensor.

[0043] (1) Load the calibration plate on the sample platform fixture and move the sample stage downward (closer to the scanning stage) (Z direction).

[0044] (3) Macro-motion mode

[0045] The macro stage moves at high speed (micrometer-level motion speed, with x, y, z directions), and the distance is monitored by the side objective (including but not limited to a sensor that can quickly extract the distance between the two planes) to see if it is <8μm (this value is determined by the maximum stroke of the selected micro stage and the minimum resolution of the sensor, and is not a fixed value). If it is not less than 8μm, continue to this step.

[0046] (4) Micro-motion mode

[0047] When the spacing meets the condition of <8μm, switch the micro-stage (nanoscale motion speed, with z-direction and θx / θy angle directions) to move.

[0048] (5) MIMO feedback system database

[0049] The objective lens monitoring data, macro stage position data, and micro stage position and angle data of the parallel light interferometer are saved into the signal and motion database in real time.

[0050] Step 3: Perform plane parallel calibration using a plane parallel calibration sensor.

[0051] (1) Parallel adjustment

[0052] The horizontal angles θx / θy are adjusted in real time using a MIMO (Multiple Input / Output) feedback controller to detect whether the three conductive probes simultaneously generate tunneling current signals; if not, the process continues.

[0053] (2) Locking parallel positioning

[0054] Parallel calibration is complete. The data of the parallel light interferometer is cleared to zero, and the mechanical position of the scanning stage is locked (at this point, it can be considered that the sample stage and the scanning stage have achieved parallelism. The clearing of the data of the parallel light interferometer indicates that the horizontal attitude θx / θy of the scanning stage is zero, and locking the mechanical position indicates that the scanning stage is positioned at zero in the z direction).

[0055] Step 4: Replace the sample, make real-time adjustments, and then perform planar scanning / etching.

[0056] (1) Replace the sample

[0057] Move upwards (away from the scanning stage) to replace the calibration plate with the sample to be scanned.

[0058] (2) Parallel placement of samples

[0059] Move the sample stage downwards (closer to the scanning stage) to the height required for scanning (this height varies from single digits to micrometers, depending on scanning / etching requirements). Adjust the horizontal angles θx / θy in real time using the MIMO feedback controller and monitor whether the data from the three parallel light interferometers are consistent. If they are inconsistent, continue this step.

[0060] (3) Start scanning / etching

[0061] The three parallel light interferometer readings are consistent, which means that the position and orientation of the sample stage are parallel to the scanning stage, and planar scanning / etching can be performed.

[0062] This invention ingeniously solves the calibration problem in mechanical / industrial applications through quantum mechanical phenomena, serving as a model of interdisciplinary research. It can promote the MEMS fabrication technology of three conductive probes, making it mature and widely used as a calibration tool. The low-cost three-probe calibration method can reduce the mechanical complexity of parallel manufacturing equipment, removing a core obstacle to industrial development. Addressing calibration stability from a materials perspective is a solution rarely conceived in the industry; it can reduce the manufacturing cost of equipment requiring calibration, providing a new solution for industry. This method has a wide range of applications, suitable for calibrating and adjusting planar horizontal plates in the tens of micrometers to sub-hundreds of nanometers range, offering more solutions for industry.

[0063] The preferred embodiments of the present invention have been described in detail above. It should be understood that those skilled in the art can make numerous modifications and variations based on the concept of the present invention without creative effort. Therefore, all technical solutions that can be obtained by those skilled in the art based on the concept of the present invention through logical analysis, reasoning, or limited experimentation on the basis of existing technology should be within the scope of protection defined by the claims.

Claims

1. A nanoscale planar parallel calibration and adjustment method, characterized in that, The process includes the following steps: Step 1: Initialize the planar parallel calibration sensor and the planar ranging adjustment sensor; Step 2: Use the planar ranging adjustment sensor to perform planar ranging adjustment; Step 3: Use the planar parallel calibration sensor to perform planar parallel calibration; Step 4: Replace the sample, adjust in real time, and then perform planar scanning / etching.

2. The nanoscale planar parallel calibration and adjustment method as described in claim 1, characterized in that, The planar parallel calibration sensor is a sensor capable of generating tunneling current, and the planar ranging adjustment sensor is a sensor capable of quickly extracting the side distance between two planes.

3. The nanoscale planar parallel calibration and adjustment method as described in claim 2, characterized in that, The number of planar parallel calibration sensors is 3, and the number of planar ranging adjustment sensors is 3.

4. The nanoscale planar parallel calibration and adjustment method as described in claim 3, characterized in that, The planar parallel calibration sensor is a parallel light interferometer, and the planar ranging adjustment sensor is a conductive probe.

5. The nanoscale planar parallel calibration and adjustment method as described in claim 4, characterized in that, Data from the parallel light interferometer and the conductive probe current data are saved into the signal database in real time.

6. The nanoscale planar parallel calibration and adjustment method as described in claim 5, characterized in that, The conductive probe material is platinum-iridium.

7. The nanoscale planar parallel calibration and adjustment method as described in claim 6, characterized in that, The ranging adjustment of the planar ranging adjustment sensor includes the macro mode of the macro stage and the micro mode of the micro stage.

8. The nanoscale planar parallel calibration and adjustment method as described in claim 7, characterized in that, The macro-motion mode has micrometer-level motion speeds in the x, y, and z directions, while the micro-motion mode has nanometer-level motion speeds in the x, y, z, and θx / θy angular directions.

9. The nanoscale planar parallel calibration and adjustment method as described in claim 8, characterized in that, The horizontal angles θx / θy are adjusted in real time using a MIMO feedback controller to detect whether the three conductive probes simultaneously generate tunneling current signals.

10. The nanoscale planar parallel calibration and adjustment method as described in claim 9, characterized in that, The objective lens monitoring data, macro stage position data, and micro stage position and angle data of the parallel light interferometer are saved into the signal and motion database in real time.

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