A nanoscale correlation imaging system based on integrated end-tip microlens

Abstract

The application discloses a kind of nanometer scale correlation imaging systems based on integrated end needle tip microlens, belong to the field of microlens optical imaging and atomic force microscope imaging technology.The system includes scanning probe microscope, microlens and probe needle tip;Sample stage is equipped on the nanometer moving platform of scanning probe microscope, cantilever beam end of scanning probe microscope is coupled microlens, probe needle tip is deposited at the bottom of microlens, optical microscope is located above microlens.The present application realizes super-resolution optical imaging by microlens combined with optical imaging system, microlens bottom needle tip synchronously carries out atomic force microscope imaging;Carry out semiconductor device manufacturing, error detection, defect positioning research, solve the problem that the reduction of device feature size and the increase of integrated circuit pattern complexity require high quality and efficiency of detection, need to be able to quickly image large area and provide circuit node level high-resolution image of high-throughput imaging.

Description

Technical Field

[0001] This invention relates to the field of microlens optical imaging and atomic force microscopy nanoimaging technology, specifically to a nanoscale correlation imaging method based on an integrated end-tip microlens. Background Technology

[0002] Since its invention in 1986, the atomic force microscope (AFM) has been widely used in high-resolution surface imaging and nanotechnology. The nanoscale resolution and high sensitivity of AFM make it extremely useful for the detection of semiconductor logic nodes. However, the scanning mode significantly limits the imaging speed and range of AFM. Furthermore, as the high-resolution imaging area of ​​AFM increases, the acquisition time increases significantly. Therefore, to overcome these limitations, it is necessary to combine AFM with auxiliary imaging techniques, such as super-resolution optical microscopy, for large-scale optical imaging and high-resolution acquisition of sample surface structure information. This enables rapid imaging across micrometer to nanometer resolution, improving the efficiency of large-scale imaging and detection. Summary of the Invention

[0003] To address the shortcomings of existing technologies, this invention provides a nanoscale correlation imaging method based on an integrated end-tip microlens. This method combines atomic force microscopy with a microlens-based optical imaging system, solving the problems of high-quality and high-efficiency detection requirements arising from the reduction in device feature size and the increase in integrated circuit pattern complexity, as well as the need for high-throughput imaging capable of rapidly imaging large areas and providing high-resolution images at the circuit node level. It achieves rapid imaging across scales from micrometer to nanometer resolution, improving the efficiency of large-scale imaging and detection based on atomic force microscopy.

[0004] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0005] A nanoscale correlation imaging system based on an integrated end-tip microlens includes a scanning probe microscope system, a microlens, and a probe tip at the bottom of the microlens. The scanning probe microscope system includes a scanning probe microscope, an optical microscope, and a probe cantilever beam. The end of the probe cantilever beam of the scanning probe microscope is coupled to the upper end of the microlens. The probe tip is located at the bottom of the microlens, and the optical microscope is positioned above the microlens. This observation system enhances the resolution of the optical microscope by using the microlens at the end of the probe cantilever beam of the scanning probe microscope, enabling real-time observation of nanoscale samples. Simultaneous atomic force microscopy imaging of the nanoscale samples is achieved through the probe tip at the bottom of the microlens and the scanning probe microscope.

[0006] The scanning probe microscope system also includes a sample stage, on which the sample to be observed is placed and the sample stage is placed on a nano-moving platform; the probe tip at the bottom of the microlens is located above the sample to be observed.

[0007] The scanning probe microscope system also includes a laser and a photoelectric sensor. The laser emits a laser beam onto the probe cantilever beam and then reflects it to the photoelectric sensor. The light emitted by the light source illuminates the sample and is reflected to the optical microscope for imaging.

[0008] The microlens is a silica microsphere, which is adhered to the end of the probe cantilever beam of the scanning probe microscope using UV-curable adhesive NOA63.

[0009] The cantilever beam is a silicon wafer or silicon nitride wafer with a length of 100-500 μm and a thickness of 0.5-5 μm. The position of the microlens attached to the probe cantilever beam should be controlled at one edge of the end of the cantilever beam to ensure that the area of ​​the microlens blocked by the cantilever beam and the UV-curable adhesive is less than 30% to avoid affecting the optical imaging performance of the microlens. The cantilever beam is used to detect the interaction force between the sample and the probe tip.

[0010] The probe tip is made of diamond and is deposited on the bottom of the microlens using a focused ion beam method. The length of the deposited tip should be within the working distance of the microlens imaging.

[0011] The scanning probe microscope used is an atomic force microscope.

[0012] The optical microscope uses the optical imaging module found in atomic force microscopes.

[0013] The present invention has the following beneficial effects and advantages:

[0014] 1. This invention combines microlenses with a traditional optical microscope to improve the imaging resolution of ordinary optical microscopes. Under white light illumination, it breaks through the diffraction limit of traditional optical microscopes, achieving an imaging resolution of 50 nanometers. This imaging method is real-time, non-destructive, and label-free, making it suitable for real-time visual feedback during nanoscale operations.

[0015] 2. This system integrates the functions of atomic force microscopy and microsphere-based optical microscopy. It can perform microlens optical imaging while performing atomic force microscopy scanning imaging. This correlated imaging helps to correct optical imaging distortion and provides optical information for the surface morphology of the sample measured by atomic force microscopy. At the same time, the correlation between the two imaging methods helps to obtain more sample information.

[0016] 3. Combining atomic force microscopy (AFM) with microsphere-based optical microscopy, a nanoscale correlation imaging system based on an integrated end-tip microlens was constructed. This system addresses the challenges of high-quality and high-efficiency detection requirements posed by the reduction in device feature size and the increase in integrated circuit pattern complexity, necessitating high-throughput imaging capable of rapidly imaging large areas and providing high-resolution images at the circuit node level. It achieves rapid cross-scale imaging from micrometer to nanometer resolution, improving the efficiency of large-scale imaging and detection based on atomic force microscopy.

[0017] 4. This invention is universally applicable to nano-manipulated objects, does not depend on sample staining agents, and is suitable for biological samples, living biological samples, and non-biological samples such as semiconductor chips and nanomaterials. Attached image description:

[0018] Figure 1 This is a schematic diagram of the system structure principle of the present invention;

[0019] Figure 2 This is a design drawing of the deposition of the needle tip at the bottom of the microlens; where: (a) is a side view, (b) is a top view, and (c) is the design and calculation of the needle tip height, diameter, and position.

[0020] Figure 3 These are electron microscope images of the probe tip deposited at the bottom of the microsphere; where: (a) is an electron microscope image of the microlens mounted at the end of the probe cantilever, with the probe tip deposited on the microlens; and (b) is a magnified view.

[0021] Figure 4 These are atomic force microscopy (AFM) images of the needle tip deposited at the bottom of the microspheres; where: (a) is an AFM scan image of the standard silicon calibration sample with an imaging range of 10 μm, and (b) is an AFM scan image of the standard silicon calibration sample with an imaging range of 20 μm.

[0022] Figure 5 These are experimental effect diagrams of the present invention; wherein: (a) is the interface of simultaneous scanning imaging by lens and atomic force microscope, (b) is an atomic force microscope image of a 220nm wide stripe structure line on a semiconductor wafer, and (c) is optical imaging enhanced by microlens.

[0023] Wherein: 1 is the nano-mobile platform (CNC mobile platform), 2 is the sample stage, 3 is the sample, 4 is the deposited needle tip, 5 is the microlens, 6 is the probe cantilever beam, 7 is the scanning probe microscope, 8 is the four-quadrant photoelectric sensor, 9 is the laser, 10 is the optical microscope, and 11 is the light source. Detailed implementation method:

[0024] The present invention will now be described in further detail with reference to the accompanying drawings and embodiments.

[0025] This invention provides a nanoscale correlation imaging system based on an integrated end-tip microlens. This system integrates scanning probe microscopy with microlens-based optical microscopy, and its implementation method is as follows.

[0026] Figure 1 The diagram shows the system structure principle of the present invention. This system integrates an atomic force microscope (AFM) system with microlens-based optical microscopy. The scanning probe microscope system includes a scanning probe microscope 7, an optical microscope 10, a probe cantilever beam 6, a laser 9, and a photoelectric sensor 8. The scanning probe microscope 7 employs an AFM, coupling the end of the probe cantilever beam of the AFM to the upper end of the microlens 5. A probe tip 4 is deposited at the bottom of the microlens 5. The microlens 5 at the end of the probe cantilever enhances the resolution of the optical microscope 10, enabling real-time observation of nanoscale samples. Through the microlens tip at the bottom and the scanning probe microscope, the nanoscale sample is simultaneously manipulated or scanned for imaging, obtaining surface structural information and realizing the function of an AFM.

[0027] The optical microscope 10 is positioned above the microlens 5. The sample 3 to be observed is placed on the sample stage 2 of the scanning probe microscope system. The sample stage is placed on the nano-moving platform 1 with piezoelectric scanning and numerical control system. The probe tip at the bottom of the microlens is positioned above the sample 3 to be observed.

[0028] The laser of the scanning probe microscope emits a laser beam onto the probe cantilever beam, which is then reflected to the photoelectric sensor (four-quadrant photoelectric sensor); light emitted by the white light source 11 illuminates the sample and is reflected to the optical microscope for imaging. The scanning probe microscope is an atomic force microscope, and the optical microscope uses the optical imaging module of an atomic force microscope.

[0029] Figure 2 The diagram shows the design of the microlens with a deposited tip at the bottom. The tip deposition process is as follows: First, silica microspheres with a diameter of 10-50 micrometers are selected as the microlens. This microlens can image in an air environment. It is then adhered to the end of the probe cantilever beam of the scanning probe microscope using UV-curable adhesive NOA63. The cantilever beam is a silicon or silicon nitride wafer with a length of 100-500 μm and a thickness of 0.5-5 μm. During microlens adhesion, its tip should be controlled to adhere to the edge of one side of the cantilever beam end, ensuring that the area of ​​the microlens obscured by the cantilever beam and UV-curable adhesive is less than 30%, so as not to affect the optical imaging performance of the microlens. The NOA63 adhesive is cured by irradiation with a 100W halogen lamp for 40 minutes, ensuring a firm and stable fixation between the microlens and the probe cantilever end. The cantilever beam is used to detect the interaction force between the sample and the tip.

[0030] The probe tip is a diamond tip, deposited at the center (lowest point) of the bottom of the microlens using a focused ion beam (FIB) technique. The tip length is less than 1 micrometer, ensuring it remains within the microlens's imaging working distance. The tip diameter is 200-500 nanometers to enable various functions such as atomic force microscopy scanning imaging of sample surfaces, nanomanipulation, and nanofabrication.

[0031] Figure 3 The image shown is an electron microscope characterization of the tip deposited at the bottom of the microspheres. This meets our design requirements for tip deposition at the bottom of the microspheres. The microlens diameter is approximately 50 micrometers, the tip length is approximately 1 micrometer, and the diameter is approximately 300 nanometers. Diamond tips were deposited using FIB (Film-In-Board) technology.

[0032] like Figure 4 Atomic force microscopy (AFM) scanning imaging tests were performed on the tips deposited at the bottom of the microlenses. Scanning imaging was performed on a periodic grid sample with a length of 5 micrometers. The imaging results show that AFM scanning imaging can be achieved for tips deposited at the bottom of microspheres using the method of this invention, with imaging performance approaching that of standard probe tips. This ensures the functionality of AFM imaging and operation.

[0033] like Figure 5 In a microlens-based nanoscale synchronous operation and observation system, ensuring the functionality of atomic force microscopy (AFM) imaging and operation, experimental verification of simultaneous AFM scanning imaging and microsphere-based optical microscopy imaging was conducted, including simultaneous imaging of the internal structure of an IC chip. This validated the effectiveness of integrating scanning probe microscopy with microlens-based optical microscopy.

[0034] This system integrates the functions of atomic force microscopy (AFM) and microsphere-based optical microscopy, enabling simultaneous AFM scanning imaging and microlens optical imaging. The correlation between these two imaging methods facilitates the acquisition of more sample information. By combining microlenses with traditional optical microscopy, the imaging resolution of ordinary optical microscopy is improved. A non-destructive, high-throughput, multi-scale correlation imaging method combining AFM and microlens scanning optical microscopy is proposed. This effectively bridges the resolution gap between traditional optical imaging and AFM, achieving rapid cross-scale imaging from micrometer to nanometer resolution and improving the efficiency of large-scale imaging and detection based on AFM. Furthermore, this method achieves nanometer-level correlation between the acquired optical images and structural information, providing a powerful tool for the detection of semiconductor devices.

Claims

1. A nanoscale correlation imaging system based on an integrated end-tip microlens, characterized in that: This nanoscale correlation imaging system includes a scanning probe microscope system, a microlens, and a probe tip at the bottom of the microlens. The scanning probe microscope system includes a scanning probe microscope, an optical microscope, and a probe cantilever beam. Specifically, the end of the probe cantilever beam of the scanning probe microscope is coupled to the upper end of the microlens, the probe tip is located at the bottom of the microlens, and the optical microscope is positioned above the microlens. This nanoscale correlation imaging system enhances the resolution of the optical microscope by using the microlens at the end of the probe cantilever beam of the scanning probe microscope, enabling real-time observation of nanoscale samples. Simultaneous atomic force microscopy imaging of the nanoscale samples is achieved through the probe tip at the bottom of the microlens and the scanning probe microscope. The probe tip is made of diamond and is deposited on the bottom of the microlens using a focused ion beam method. The length of the deposited tip is within the working distance of the microlens imaging.

2. The nanoscale correlation imaging system based on an integrated end-tip microlens according to claim 1, characterized in that: The scanning probe microscope system also includes a sample stage, on which the sample to be observed is placed and the sample stage is placed on a nano-moving platform; the probe tip at the bottom of the microlens is located above the sample to be observed.

3. The nanoscale correlation imaging system based on an integrated end-tip microlens according to claim 1, characterized in that: The scanning probe microscope system also includes a laser and a photoelectric sensor. The laser emits a laser beam onto the probe cantilever beam and then reflects it to the photoelectric sensor. The light emitted by the light source illuminates the sample and is reflected to the optical microscope for imaging.

4. The nanoscale correlation imaging system based on an integrated end-tip microlens according to claim 1, characterized in that: The microlens is a silica microsphere, which is adhered to the end of the cantilever beam of the probe (3) of the scanning probe microscope by UV-curing adhesive NOA63.

5. The nanoscale correlation imaging system based on an integrated end-tip microlens according to claim 4, characterized in that: The cantilever beam is a silicon wafer or silicon nitride wafer with a length of 100-500 μm and a thickness of 0.5-5 μm. The position of the microlens attached to the probe cantilever beam should be controlled at one edge of the end of the cantilever beam to ensure that the area of ​​the microlens blocked by the cantilever beam and the UV-curable adhesive is less than 30% to avoid affecting the optical imaging performance of the microlens. The cantilever beam is used to detect the interaction force between the sample and the probe tip.

6. The nanoscale correlation imaging system based on an integrated end-tip microlens according to claim 1, characterized in that: The scanning probe microscope used is an atomic force microscope.

7. The nanoscale correlation imaging system based on an integrated end-tip microlens according to claim 1, characterized in that: The optical microscope uses the optical imaging module found in atomic force microscopes.

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