Fine microscope system, laser processing device, monitoring device, and electronic device production method

Abstract

A fine microscope system according to the present invention comprises: an objective lens that takes in light from a sample; and an image sensor that captures an image of the light taken in by the objective lens, wherein the image sensor has a pixel size in the range of 1-4 μm, and the resolution of a microlens provided on the image sensor is in the range of 1.20-2.20 times the resolution of the objective lens.

Description

Microscopic System, Laser Processing Apparatus, Monitoring Apparatus, and Method for Manufacturing Electronic Device

[0001] The present invention relates to a microscopic system, a laser processing apparatus, a monitoring apparatus, and a method for manufacturing an electronic device, and more particularly to a microscopic system that enables microscopic observation by an optical microscope.

[0002] Conventionally, in an optical microscope, a technique of forming an image of an object from an objective lens on an image sensor to obtain an optical video of the object to be observed has been widely used. The optical microscope has the advantages of being able to observe a sample nondestructively and having relatively few restrictions on the size of the object to be observed (see Patent Document 1).

[0003] Japanese Patent Application Laid-Open No. 2016-102744

[0004] However, in a conventional optical microscope system, for an object of about 10 μm, only its contour can barely be observed, and it does not have the performance comparable to that of a scanning electron microscope (hereinafter referred to as "SEM"). Therefore, when microscopic observation is required, the sample size is limited, and an SEM that may damage the sample has to be used. On the other hand, an SEM uses an electron beam and forms an image by detecting secondary electrons and reflected electrons emitted from the sample surface. In this method, it is possible to observe extremely fine structures at the level of several nm, but since observation needs to be performed in a vacuum chamber, there is a limit to the size of the object to be observed. There is also a problem that the sample may be damaged by the electron beam.

[0005] The present invention has been made in view of such problems, and an object thereof is to achieve resolution performance close to that of an SEM with an optical microscope.

[0006] To solve the above problems, the micromicroscope system according to the present invention comprises an objective lens for capturing light from a sample and an image sensor for capturing an image of the light captured by the objective lens, wherein the pixel size (side of a square) of the image sensor is in the range of 1.0 μm to 4.0 μm, and a microlens corresponding one-to-one with each pixel is provided at the light-receiving position of the image sensor, and the resolution of the microlens is in the range of 1.20 times or more and 2.20 times or less the resolution of the objective lens. In a preferred embodiment of the present invention, the pixel size of the image sensor is in the range of 1.5 μm to 3.0 μm. Furthermore, in another embodiment of the present invention, the system further comprises an imaging lens for forming an image of the light captured by the objective lens on the image sensor, and the resolution of the imaging lens may be 3.5 times or more the resolution of the microlens and 50 times or less the resolution of the objective lens.

[0007] The present invention provides the following advantages: (1) By optimizing the pixel size of the image sensor, it is possible to achieve resolution performance close to that of a SEM, even though it is an optical microscope. In particular, by setting the pixel size in the range of 1.5 μm to 3.0 μm, imaging results that fall within the range of a good SEM can be obtained, and by optimizing the resolution of the objective lens and the resolution of the microlenses attached to the image sensor, a finer observation environment can be realized. (2) By optimizing the resolution of the imaging lens and the resolution of the microlenses, degradation of image quality can be prevented, and by optimizing the resolution of the imaging lens and the resolution of the objective lens, the system can be made larger. (3) The micromicroscope system of the present invention can observe samples non-destructively and does not require a vacuum chamber, making it suitable for observing large samples. It also has advantages over SEM in terms of equipment cost and operating costs. (4) The micromicroscope system of the present invention is suitable for observing structures ranging from 200 nm to several mm and can be applied to various industrial applications such as inspection processes in semiconductor manufacturing processes and confirmation of processing positions in laser processing equipment.

[0008] This is a schematic diagram showing an overview of an example of a microscopy system according to one embodiment of the present invention. This is a schematic diagram showing the optical system of the image sensor in the microscopy system according to one embodiment of the present invention. This is a diagram showing an example of a specific usage mode of the microscopy system according to one embodiment of the present invention. This is a schematic diagram showing a cross-section of a pixel in particular of the image sensor in the microscopy system according to one embodiment of the present invention. This is a diagram showing an overview of the stage in the microscopy system according to one embodiment of the present invention. This is a diagram showing an overview of the vertical movement function of the microscopy system in Figure 1. This is a schematic diagram showing various microscopes equipped in the microscopy system according to one embodiment of the present invention. This is a diagram showing the relationship between the pixel size of the sensor in the microscopy system according to one embodiment of the present invention and factors affecting the performance of the microscopy system. This is a diagram showing the relationship between the size of the sensor in the microscopy system according to one embodiment of the present invention and the yield and field of view. This is a diagram showing the repeatability position accuracy of the stage in the microscopy system according to one embodiment of the present invention. This is a diagram showing the inclination of the stage in the microscopy system according to one embodiment of the present invention. This is a diagram showing the relationship between the characteristics of the stage in the microscopy system according to one embodiment of the present invention and the display resolution. This is an example of an image taken by the microscopy system according to one embodiment of the present invention. This is an example of an image taken by SEM of the part shown in Figure 11. This is an example of an image taken by the microscopy system according to one embodiment of the present invention. This is an example of an image taken by the microscopy system according to one embodiment of the present invention. This is an example of an image taken by a microscopy system according to one embodiment of the present invention. This is a schematic diagram showing an example of a laser irradiation device being arranged in a microscopy system according to one embodiment of the present invention. This is a block diagram showing the hardware configuration of an information processing device according to one embodiment of the present invention. This is a functional block diagram showing an example of the functional configuration of a microscopy system according to one embodiment of the present invention.

[0009] Embodiments of the present invention will be disclosed below and described with reference to the drawings.

[0010] First, an overview of a micromicroscope system S according to one embodiment of the present disclosure will be described with reference to Figures 1 to 5. Figure 1 is a diagram showing an overview of an example of a micromicroscope system S according to one embodiment of the present disclosure.

[0011] The micromicroscope system S shown in Figure 1 comprises an objective lens 31, a revolving nosepiece 32, a microscope tube 33, an imaging unit 34, an extension mount 35, a stage 36, and a microscope tube vertical adjustment unit 37.

[0012] The objective lens 31 is positioned closest to the sample and is an optical element that captures light from the sample to form a high-magnification image of the sample. As shown in Figure 2, this micromicroscope system S has an infinity correction optical system 38. The objective lens 31 in this embodiment has a numerical aperture (NA) of 0.5, thereby achieving high resolution. In another embodiment of this disclosure, the objective lens 31 may be a solid immersion lens or a liquid immersion lens, in which case the numerical aperture (NA) can be about 0.9 or about 1.4.

[0013] Figure 2 shows the relationship between the long-focus objective lens 31 and the sample. This micromicroscope system S is equipped with a long-focus objective lens 31. The long-focus objective lens 31 is an optical system designed with a longer working distance compared to a general objective lens. As shown in Figure 2, the distance from the sample surface to the front surface of the objective lens 31 is about two to three times that of a normal objective lens, greatly improving the operability of the sample. This long working distance is achieved by appropriately combining multiple convex and concave lenses. In the example in Figure 2, a distance of 10 mm or more is ensured between the objective lens 31 and the sample.

[0014] The long-focus objective lens 31 employs special optical glass to highly correct various aberrations such as chromatic aberration and spherical aberration. Furthermore, an anti-reflective coating is applied to the lens surface to suppress ghosting and flare. The objective lens 31 is particularly effective in applications requiring sufficient space between the sample and the objective lens 31, such as semiconductor wafer inspection and observation of large samples. Additionally, when combined with a laser processing machine, its long working distance allows for the coexistence of the processing laser beam and the observation optical system.

[0015] Long-focus objective lenses can play a particularly important role in inspection processes within semiconductor manufacturing. They allow for inspection of defects on glass masks or wafer surfaces, verification of patterning accuracy, and inspection of film deposition or wiring layers without damaging the sample. They are especially useful for safely observing the edges of large wafers. Furthermore, their suitability for cleanroom environments makes them an indispensable tool for quality control in semiconductor manufacturing.

[0016] In quality control of electronic components, non-destructive inspection is possible even for objects with three-dimensional component arrangements, such as checking the mounting status of printed circuit boards, inspecting solder joints, and observing the surface of electronic components. This significantly improves work efficiency and streamlines the quality control process on the manufacturing line.

[0017] In the field of materials research and development, it can be used for observing crystal growth processes, analyzing the microstructure of material surfaces, and observing the layer structure of thin films. Observation is possible even when using a sample chamber, and it can also be used for observation under temperature-controlled conditions. Long-term continuous observation is possible, making it useful in research tracking the temporal changes of materials.

[0018] In the field of biotechnology, it can be used for observing cells in large culture vessels, tissue sections, and samples in microplates. The ability to observe while maintaining the culture environment is extremely important in live cell imaging. Because it is suitable for observation from the bottom of the vessel, continuous monitoring of cultured cells is possible. Furthermore, since it reduces the risk of contamination during observation, it is considered safe to use even in experiments requiring a sterile environment.

[0019] Returning to Figure 1, the revolving nosepiece 32 is a mechanism that allows for the rapid switching between objective lenses 31 with different magnifications by mounting and rotating multiple objective lenses 31. The rotation mechanism is equipped with a click mechanism, which allows the optical axis of the objective lens 31 to be precisely aligned with the center of the lens barrel 33.

[0020] The microscope tube 33 houses an optical system that guides the image formed by the objective lens 31 to the imaging unit 34, below the infinity correction optical system 38. This micromicroscope system S has an infinity correction optical system 38. The microscope tube 33 is designed to minimize image distortion and chromatic aberration, thereby enabling the acquisition of high-quality images. As shown in Figure 2, the infinity correction optical system 38 is configured such that the objective lens 31 captures light incident from a single point on the sample so that it becomes parallel rays, and then uses an imaging lens 381 to form an image on the image sensor 341.

[0021] The imaging unit 34 has an image sensor 341, which is not shown in Figure 1 but is shown in Figure 4. The image sensor 341 has pixels 3411 arranged regularly in a vertical and horizontal direction. Each pixel 3411 has a microlens 3412 that focuses incident light, a photodiode 3413 that converts the incident light into an electrical signal, and a metal wiring 3414 that sends the electrical signal to a processing circuit. In a digital microscope system, the image sensor 341 plays the role of electronically recording the observed image. There are various types such as CMOS and CCD, and characteristics such as size, resolution, and sensitivity greatly affect the observation results.

[0022] As will be described in detail later, the image sensor 341 comes in a diverse range of sizes from 1 / 4 inch to 1.1 inch. The larger the sensor size, the larger the individual pixel size (the length of one side of a square pixel 3411) can be, even with the same number of pixels, which leads to improvements in sensitivity and gradation characteristics. The image sensor 341 has pixels 3411 with a size of 1 μm to 4 μm, and preferably pixels 3411 with a size of 1.5 μm to 3 μm. In this embodiment, the image sensor 341 has, for example, a number of pixels of 4096 × 3000.

[0023] As will be described in detail later, for example, the image sensor 341 of the following three embodiments can be used. The image sensor 341 of the first embodiment has a pixel size of 2.78 μm, a sensor size of 11.4 mm × 8.3 mm, and a focal length of 3.2 μm for the microlens 3412. The image sensor 341 of the second embodiment has a pixel size of 1.85 μm, a sensor size of 7.4 mm × 5.6 mm, and a focal length of 1.8 μm for the microlens 3412. The image sensor 341 of the third embodiment has a pixel size of 3.45 μm, a sensor size of 14.1 mm × 10.4 mm, and a focal length of 3.6 μm for the microlens 3412.

[0024] A microlens 3412 is formed in each pixel 3411 of the image sensor 341. The microlens 3412 collects the light of the real image formed at the position of the pixel 3411 and guides it to, for example, a photodiode. As will be described in detail later, a characteristic configuration of this disclosure is that the resolution of the microlens 3412 is designed to be in the range of 1.20 times or more and 2.20 times or less the resolution of the objective lens 31, preferably in the range of 1.50 times or more and 1.90 times or less.

[0025] If a high-resolution lens exists between the objective lens 31 and the microlens 3412, the light captured by the objective lens 31 may be diffused by diffraction, potentially resulting in a blurred image on the image sensor 341. For this reason, the resolution of the imaging lens 381 is desirable to be sufficiently larger than the resolution of the microlens 3412, preferably 3.5 times or more, and more preferably 4.0 times or more. Furthermore, if the resolution of the imaging lens 381 is made too large, it becomes necessary to increase the distance to the image sensor 341, making the micromicroscope system S unnecessarily large. For this reason, the resolution of the imaging lens 381 is preferably designed to be 50 times or less, and more preferably 30 times or less, the resolution of the objective lens.

[0026] The expansion mount 35 is a mount for arranging a laser light source, an expansion imaging unit, etc., in the micromicroscope system S, which will be described later.

[0027] Figure 5 shows the stage 36, which serves as the sample holder. It has an XYZθ axis adjustment mechanism, and a stepping motor 361 enables precise position adjustment of the sample. Specifically, it can perform horizontal movement in the X and Y axes, focus adjustment in the Z axis, and rotational adjustment in the θ axis. The stage 36 holds the sample, for example, with an electrostatic chuck and has a tilt adjustment function.

[0028] In this disclosure, the stage 36 has high precision. Specifically, in terms of horizontality, the maximum height difference in a 100 mm square area is 14 μm or less, and in terms of flatness, the cutting precision is 5 μm or less in a 100 mm square area. Furthermore, the repeatability of the X and Y axes is 80 nm, and the precision of the Z axis is 1 μm. The stage 36 is calibrated using a linear scale, and appropriate warm-up is performed before use. In addition, the stage 36 is compatible with an optical system with a depth of field of 1 μm. This micromicroscope system S uses light with a wavelength of 0.4 μm, for example, and the sample imaging size per pixel is 27.8 nm. As a result, the micromicroscope system S achieves an assumed resolution of approximately 80 nm.

[0029] Figure 6 shows the vertical adjustment section 37 of the microscope tube 33 of the micromicroscope. The vertical adjustment section 37 of the micromicroscope system S is a mechanism for precisely focusing on a sample. The vertical adjustment section 37 is equipped with a coarse adjustment handle and a fine adjustment handle. The coarse adjustment handle allows for large vertical movements and approximate focusing. On the other hand, the fine adjustment handle enables highly accurate vertical movements and precise focusing. The vertical adjustment section 37 employs a rack and pinion mechanism, and smooth vertical movement is achieved by the meshing of the rack gear and pinion gear.

[0030] Figure 7 shows that the micromicroscope system S according to this disclosure integrates the functions of a stereomicroscope, a metallurgical microscope, and a scanning electron microscope (SEM). The characteristics of each microscope and their integration in this disclosure are described below. A stereomicroscope is an optical microscope that can observe a sample in three dimensions. A stereomicroscope has a pair of objective lenses and is characterized by its ability to observe a sample in three dimensions. In addition, a stereomicroscope has the advantage of a relatively long working distance, easy insertion and removal of the sample, and the ability to observe the surface shape of the sample in three dimensions. On the other hand, a stereomicroscope generally has a low magnification and is not suitable for fine observation. A metallurgical microscope is an optical microscope for observing the surface of opaque samples such as metals. A metallurgical microscope is characterized by its ability to observe reflected light from the sample surface using reflected illumination. A metallurgical microscope can observe the microstructure and crystalline structure of the sample surface and is widely used for microstructural observation and quality control of metallic materials. However, a metallurgical microscope has the problem that the observable range is limited to the sample surface and it is difficult to obtain information in the depth direction. A scanning electron microscope (SEM) is a microscope that observes a sample using an electron beam. SEM (Scanning Electron Microscope) has the characteristic of being able to observe extremely fine structures that exceed the resolution of optical microscopes. In particular, SEM can observe the shape of the sample surface with high resolution, making it possible to observe fine structures at the nanometer level. However, SEM has challenges such as requiring observation in a vacuum chamber, limiting the sample size, and the possibility of damaging the sample with the electron beam.

[0031] The micromicroscope system S described herein integrates the functions of these three types of microscopes as follows. Firstly, the micromicroscope system S has a stage 36 with an XYZθ axis adjustment mechanism and a tilt adjustment function, enabling three-dimensional observation of the sample, similar to a stereomicroscope. Furthermore, by having an optical system with a depth of field of 1 μm, the surface shape of the sample can be observed precisely. Secondly, the micromicroscope system S can observe the fine structure of the sample surface with high resolution, similar to a metallurgical microscope. In particular, by employing an image sensor 341 with a pixel size in the range of 1 μm to 4 μm and optimizing the resolution of the microlens 3412, it achieves high-resolution observation that surpasses conventional metallurgical microscopes. Thirdly, the micromicroscope system S has a resolution of approximately 80 nm, achieving observation performance close to that of a SEM. Moreover, because it uses an optical system, it does not require a vacuum chamber and can observe the sample without damaging it. Furthermore, there are fewer limitations on sample size, and observation of large samples is possible.

[0032] Thus, the micromicroscope system S described herein integrates the stereoscopic observation function of a stereomicroscope, the surface observation function of a metallurgical microscope, and the high-resolution observation function of a scanning electron microscope (SEM), realizing a novel observation system that solves the problems of each microscope. As a result, it is possible to meet a wide range of observation requirements with a single device, from three-dimensional observation of a sample to observation of its microstructure.

[0033] The resolution of the images captured in this micromicroscope system S is described below. The resolution of the objective lens 31 is defined as the minimum distance at which the lens can distinguish objects, and is expressed by the following equation in the sense that they are approximately equal: d <> fλ / D = λF (Equation 1) Here, since F = 0.5 / NA, d <> 0.5λ / NA (Equation 2) Here, each parameter has the following meaning: d: diffusion limit λ: wavelength of light f: focal length of the lens D: diameter of the aperture F: F value (F = f / D) (Equation 3) NA: numerical aperture (NA = 1 / 2F) (Equation 4)

[0034] For example, when using a target lens with a wavelength of 355 nm (blue light) and an NA of 0.5, the theoretical diffraction limit is approximately 355 nm (= 355 nm / (2 * 0.5)) nm. The digital microscope system of this embodiment employs an optical system in which the real image from the objective lens 31 is formed on the sensor surface of the imaging device by the imaging lens 381.

[0035] Here, the concept of the Nyquist frequency is important. According to the Nyquist-Shannon sampling theorem, in order to perfectly reproduce the original signal, sampling must be performed at a frequency of at least twice the highest frequency contained in the signal. Applying this concept to a microscope system, it is desirable to sample at intervals of no more than twice the resolution of the objective lens 31. Furthermore, the size of the image on the surface of the image sensor 341 that matches the resolution (diffraction limit) of the objective lens 31 is expressed by the following equation: Size on the surface of image sensor 341 = d (Equation 5) Here, d is the resolution (diffraction limit) of the objective lens 31, and M is the overall magnification of the optical system. For example, if the resolution (diffraction limit) is 355 nm and the overall magnification is 100x, the pixel size corresponding to the diffraction limit is approximately 35.5 (= 355 nm * 100 / 2) μm. Since it is desirable to sample at intervals of no more than twice this diffraction limit, it can be seen that the pixel size of the image sensor 341 is preferably 17.8 μm (= 35.5 μm / 2) or less.

[0036] The applicant has obtained the following technical findings: The larger the numerical aperture (NA) of the objective lens 31, and the smaller the wavelength λ of light, the smaller the diffraction limit d. Furthermore, the larger the diameter D of the aperture, the smaller the F-number, which in turn increases the NA and thus the diffraction limit d. On the other hand, theoretically, increasing the pixel size allows more light to be incident, thereby reducing the diffraction limit. However, if the pixel 3411 is too large, the distribution of light intensity within the pixel plane causes loss of information in the real image, which is counterproductive to improving resolution. Therefore, the applicant has found that there is an optimal range for the pixel size.

[0037] Based on the above verification, the applicant further investigated the pixel size, microlens 3412, imaging lens 381, and stage 36. Figure 8 shows the results of verifying the relationship between pixel size, the number of pixels 3411 relative to the resolution limit, and the amount of light per unit pixel. It was found that as the pixel size increased, the amount of light per pixel increased, and the resolution in the grayscale direction improved. On the other hand, it was confirmed that as the pixel size increased, the number of pixels relative to the diffraction-limit equivalent pixel size (35.5 μm) decreased. Specifically, there were approximately 35 pixels for a pixel size of 1 μm, 17 for 2 μm, and approximately 10 for 3 μm. As a result of evaluating multiple image sensors 341 of the same size with varying pixel sizes, it was found that good imaging images could be obtained in the range of pixel sizes from 1 μm to 4 μm. In particular, image sensors 341 with pixels 3411 ranging from 1.5 μm to 3 μm obtained imaging results comparable to those of an SEM.

[0038] Figure 9 shows the relationship between the size of the image sensor 341, the field of view, and the manufacturing yield. It was found that as the sensor size increases, the field of view expands, but the number of image sensors 341 that can be acquired from the Si wafer decreases, and the yield decreases significantly due to foreign matter contamination.

[0039] The microlenses 3412 formed on each pixel 3411 of the image sensor 341 have the function of focusing the real image light at the pixel position and guiding it to the photodiode. The applicant has found that the resolution of these microlenses 3412 has a significant effect on the performance of the micromicroscope system S. Equations (1) and (2) described above were evaluated for the sensor. For example, consider the case where the pixel size is 2.78 μm (used in the embodiment described later). d <> fλ / D = 0.46 μm (= 3.2 μm × 0.4 μm (in the case of blue illumination) / 2.78 μm (pixel size)). This result is called Result 1. On the other hand, when the relationship is calculated for the objective lens 31, d <> 0.5λ / NA = 0.5 × 0.4 / 0.5 = 0.4 μm (NA = 0.5 is the NA value of the objective lens 31 used during imaging). This result is called Result 2. Comparing result 1 and result 2 above, in the above example, the resolution of the microlens 3412 is inferior to the resolution of the objective lens 31, and is therefore considered to determine the overall performance. Furthermore, it can be estimated that if both the d value of the image sensor 341 (CMOS sensor) and the d value of the objective lens 31 can be reduced, an even finer observation environment can be realized. From another perspective, once the resolution d of the objective lens 31 is determined, it becomes important to set the resolution of the image sensor 341 accordingly. Even if the resolution of the image sensor 341 is reduced, the resolution of the objective lens 31 becomes dominant. As described above, selecting the image sensor 341, microlens 3412, and objective lens 31 according to the above theory within the optimal range of pixel size can serve as a criterion for selecting a finer environment.

[0040] Furthermore, the performance of stage 36 was examined. Figure 10 shows the repeatable position accuracy of stage 36 in the XY axis direction. The horizontal axis represents the number of repetitions, and the vertical axis represents the XY repeatable position accuracy. The XY repeatable position accuracy represents the difference from the expected value, and the unit is μm. The difference from the expected value was 0.06 μm or less, and an average of approximately 0.02 μm was achieved.

[0041] Figure 11 shows an example of the inclination of the stage 36. The X and Y axes represent the in-plane position of the stage 36, and the Z axis represents the height of the stage 36. The height of the stage 36 was evaluated with the X axis set to ±25 μm and the Y axis set to a range of -20 μm to +15 μm. As a result, the maximum height difference was 15 μm. Based on these repeatability accuracy and inclination evaluation results, the stage 36 was optimized.

[0042] Figure 12 shows the effect of the tilt angle and cutting accuracy of the stage 36 on the resolution of the captured image. The horizontal axis (X-axis) represents the tilt angle of the stage 36, expressed as the difference in height between the highest and lowest points in a 100 mm square area, and the vertical axis (Y-axis) represents the cutting accuracy of the stage 36. Figure 12 is a contour plot, and the Z-axis represents the resolution. It was found that the resolution of the captured image improves as the tilt angle and cutting accuracy of the stage 36 decrease. The depth of field assumed for the micromicroscope system S according to this disclosure is approximately ±1 μm. Focusing was achieved on a pattern or alignment mark on a silicon wafer, achieving a height accuracy of ±1 μm. Furthermore, a height accuracy of ±1 μm was achieved at two or more positions using the tilt function of the stage 36. This made it possible to achieve a tilt angle of 14 μm or less. As shown in Figure 12, a repeatability of 80 nm was achieved under conditions of a tilt angle of 14 μm or less and a cutting accuracy of 5 μm. To maintain the positioning accuracy of Stage 36, a warm-up operation and calibration using a linear scale are performed before use. A linear scale is a measuring instrument that enables high-precision linear measurement, and has precise markings engraved on a substrate such as metal or glass, which can be read optically or electrically. Calibration is performed, for example, by the following procedure: a) Precisely position the linear scale along the X and Y axes. b) Set a specific mark on the linear scale as the reference point. c) Move Stage 36 by a known distance using the stage control system. d) Measure the actual amount of movement using the linear scale (visual observation using an optical system or using an electronic sensor). e) Calculate the error from the difference between the indicated amount of movement and the measured amount of movement. f) Adjust the parameters of the stage control system based on the calculated error. g) After correction, repeat the movement and measurement to confirm that the error is within the acceptable range.

[0043] Next, multiple types of image sensors 341 were prepared and the captured images were evaluated. As the image sensors 341, a plurality of sensor elements with pixel 3411 sizes of 0.70 μm, 1.85 μm, 2.78 μm, and 3.45 μm respectively were prepared, and microlenses 3412 with a resolution dm of 0.24 μm to 5.86 μm were formed. As the objective lens 31, one with a resolution do of 0.22 μm was prepared, and as the imaging lens, one with a resolution di of 1.54 μm was prepared. The performance of the prototype fine microscope system S assembled by combining these was evaluated by whether each test pattern with a line and space of 0.2 μm, 0.4 μm, 0.8 μm, 1.6 μm, and 3.2 μm respectively could be recognized. The illumination wavelength was set to 0.4 μm. The following table shows the configuration of the prototype microscope system and the line pitch of the smallest test pattern that could be recognized (for those that could not be recognized at all, it is "NA"). The table also shows the ratio (dm / do) of the resolution dm of the microlens 3412 to the resolution do of the objective lens 31, the ratio (di / dm) of the resolution di of the imaging lens to the resolution dm of the microlens 3412, and the ratio (di / do) of the resolution di of the imaging lens to the resolution do of the objective lens 31.

[0044]

[0045] From Table 1, it was confirmed that by setting the ratio (dm / do) of the resolution dm of the microlens 3412 to the resolution do of the objective lens 31 within a certain range, the resolution performance of the fine microscope system S can be improved. Specifically, it was confirmed that by setting the ratio of resolution (dm / do) to be 1.2 or more and 2.2 or less, preferably 1.5 or more and 1.9 or less, the minimum recognition size can be reduced.

[0046] Furthermore, the results of observing the surface of a metal plate in which holes with diameters of 10 μm, 5 μm, and 1 μm were formed by laser irradiation using the prototype microscope system S of prototype No. 1 are shown in FIG. 13, and the results of observing the same sample with an SEM are shown in FIG. 14. Thus, the microscope system S of the present disclosure can confirm not only the formed holes but also the debris scattered around, and exhibits performance comparable to that of an SEM. On the other hand, with the microscope system S of prototype No. 5, the shape of the 1-μm-sized hole could not be observed, and furthermore, submicron-sized debris generated during the hole machining was invisible. Furthermore, for reference, an observation example using the microscope system S of prototype No. 2 is shown in FIG. 15, an observation example using the microscope system S of prototype No. 3 is shown in FIG. 16, and an observation example using the microscope system S of prototype No. 4 is shown in FIG. 17, respectively.

[0047] Furthermore, as the objective lens 31, those having resolutions of 0.12 μm, 0.16 μm, 0.18 μm, 0.22 μm, 0.24 μm, 0.25 μm, 0.27 μm, 0.29 μm, 0.31 μm, 0.33 μm, 0.36 μm, 0.40 μm, 0.44 μm, and 0.50 μm were prepared, and a prototype microscope system S was fabricated by combining them with an image sensor 341 having a pixel size of 1.85 μm and a resolution of the microlens of 1.85 μm and an imaging lens 381 having a resolution of 3.30 μm, and the performance was evaluated using the same test pattern. The results are shown in Table 2 below.

[0048]

[0049] Table 2 shows that, similar to Table 1 in which the resolution do of the objective lens 31 is fixed and the resolution dm of the microlens 3412 is changed, even when the resolution dm of the microlens 3412 is fixed and the resolution do of the objective lens 31 is changed, by setting the ratio (dm / do) of the resolution dm of the microlens 3412 to the resolution do of the objective lens 31 within a certain range, the resolution performance of the microscope system S can be improved.

[0050] Furthermore, imaging lenses 381 with resolutions of 0.80 μm, 1.00 μm, 1.20 μm, 1.40 μm, 1.54 μm, and 2.00 μm were prepared, and a prototype micromicroscope system S was fabricated by combining these with an image sensor 341 having a pixel size of 3.45 μm and a microlens resolution of 0.39 μm, and an objective lens 31 having a resolution of 0.22 μm. The performance was evaluated using the same test pattern. The results are shown in Table 3.

[0051]

[0052] Table 3 shows that by further setting the ratio of the resolution di of the imaging lens 381 to the resolution dm of the microlens 3412 (di / do) to 3.5 or higher, it can be confirmed that no diffusion of image information occurs within the optical system, and the performance of the combination of the objective lens 31 and the microlens 3412 can be guaranteed.

[0053] The micromicroscope system S described herein is a device that observes microstructures based on a principle different from that of a scanning electron microscope (SEM). The effectiveness of this disclosure will be explained below by comparing the characteristics of both systems.

[0054] The micromicroscope system S disclosed herein employs an optical system that uses visible light and a lens system to magnify and observe a sample. This optical system enables non-destructive sample observation and has the advantage of relatively few limitations regarding the size of the object to be observed. The observation range of the micromicroscope system S is approximately 200 nm to several millimeters.

[0055] In contrast, a scanning electron microscope (SEM) forms an image by irradiating a sample with an electron beam and detecting secondary electrons and backscattered electrons emitted from the sample surface. While SEMs can observe extremely fine structures down to the level of a few nanometers, the size of the object being observed is limited because observation must take place in a vacuum chamber. The typical observation range of an SEM is from a few nanometers to several hundred micrometers.

[0056] The micromicroscope system S of this disclosure has the following advantages compared to a scanning electron microscope (SEM). First, it enables non-destructive observation. While a sample may be damaged by the electron beam in an SEM, the micromicroscope system S allows the sample to be observed in its original state. This feature is particularly important for observing biological samples and materials that are easily altered. Second, it does not require a vacuum chamber, making it possible to observe large samples. Third, it has low equipment and operating costs, relatively simple sample preparation, and allows for shorter observation times.

[0057] The micro-microscope system S disclosed herein is particularly effective in the following applications. For example, it is suitable for observing structures of 200 nm or larger in sampling inspections and partial inspections. It can also be applied to whole-product inspections (in-line), and when combined with high-speed planar scanning technology, it can realize rapid inspection on the production line. The micro-microscope system S disclosed herein solves the fundamental problems of conventional inspection processes using SEM (scanning electron microscopes) and is a system that enables whole-product inspection. In particular, it leverages its non-destructive characteristics to enable continuous quality control on the manufacturing line.

[0058] In SEM (Scanning Electron Microscope) inspections can cause serious problems such as surface charging of samples, breakage of molecular bonds in organic materials, changes in semiconductor device properties, and alteration of resist materials due to electron beam irradiation. In contrast, this system uses visible light for observation, so no charge accumulation occurs on the sample, and the chemical bonding state of the material is preserved. Furthermore, it does not affect device properties, and even photosensitive materials can be observed by selecting an appropriate wavelength.

[0059] The effectiveness of this system in 100% inspection lies in its non-destructive testing capabilities. It allows observation without altering the electrical properties of the sample, resulting in no impact on subsequent processes. This makes it possible to ship inspected products directly. Furthermore, since sample pretreatment and vacuuming are unnecessary, combining this system with high-speed planar scanning technology enables wide-area observation in a short time.

[0060] It has high compatibility with inline inspection systems and possesses sufficient resolution for observing structures of 200 nm or larger. Because it enables real-time defect detection, it allows for continuous quality control on the manufacturing line. This meets the advanced quality control needs demanded by the manufacturing industry.

[0061] The introduction of this system will eliminate bottlenecks in the inspection process, leading to improved product quality and increased production efficiency. It will also enable improved yield through early detection of defective products. This system, which enables 100% inspection—something difficult to achieve with conventional SEMs—possesses a significant technological advantage in meeting modern, advanced quality control requirements due to its non-destructive nature. Achieving 100% inspection on the manufacturing line will greatly contribute to improved product quality and increased production efficiency.

[0062] The micromicroscope system S and SEM of this disclosure can be effectively used in the following ways. The micromicroscope system S is suitable for observing structures ranging from 200 nm to several millimeters in size, and is effective for observing samples requiring non-destructive observation, large samples, and high-speed in-line inspection. On the other hand, the SEM is suitable for observing microstructures smaller than 200 nm and for observing detailed surface shapes. Furthermore, the SEM can also perform elemental analysis by combining it with energy-dispersive X-ray spectroscopy (EDS), and is selected when nanoscale observation or material composition analysis is required.

[0063] Thus, the micro-microscope system S of this disclosure enables non-destructive observation and observation of large samples, which were not possible with conventional SEMs, and provides a new observation method for industrial applications.

[0064] The micromicroscope system S of this disclosure has a laser light irradiation function, as shown in Figure 18. A laser light source 39 is installed at the top of the microscope tube 33.

[0065] In semiconductor devices, the development of three-dimensional structures such as through-electrode structures, embedded wiring structures, and multilayer wiring structures is progressing in line with the increasing integration and performance of semiconductor devices. In particular, micro-porous structures such as TSVs (Through-Silicon Vias) that penetrate silicon substrates, via holes connecting insulating layers, and deep trenches formed to a predetermined depth from the substrate surface are important elements in high-density mounting of devices. Conventionally, plasma etching has been the main processing method used for processing of 5 μm or less in the formation of these micro-porous structures. However, this method requires dedicated photomasks or hard masks for each processing type, resulting in challenges such as long manufacturing preparation periods and mask production costs of several million yen. Furthermore, when forming multiple micro-porous structures with different depths or aspect ratios on the same substrate, multiple masking processes are required, leading to technical challenges such as increased process complexity. Such micro-porous structures require various cross-sectional shapes depending on the application, such as cylindrical, prismatic, or frustoconical shapes. Furthermore, the depth of these pores varies widely, from shallow structures only in the surface layer to structures that completely penetrate the substrate, and the diameter also needs to range from submicron to tens of microns. In addition, these micropores need to be formed not only in silicon substrates, but also in various materials such as glass substrates, ceramic substrates, and resin substrates. In particular, when forming micropores in composite substrates where multiple dissimilar materials are laminated, it is necessary to set optimal processing conditions according to the material properties of each layer.

[0066] The laser processing apparatus of this disclosure includes a control unit. The specific functional configuration of the control unit will be described later. The control unit controls the irradiation position of the laser beam based on an image acquired by an image sensor 341. Specifically, it detects the position of the workpiece from the image acquired by the image sensor 341 and controls the irradiation position of the laser beam with an accuracy of ±90 nm or less based on the detected position information.

[0067] Furthermore, the control unit detects the three-dimensional shape of the workpiece from the image acquired by the image sensor 341 through image analysis. Based on the detected three-dimensional shape, the focus position of the laser beam is controlled. This makes it possible to achieve the optimal machining depth according to the surface shape of the workpiece.

[0068] In this embodiment, lasers with wavelengths of 266 nm, 355 nm, and 1064 nm are used as the laser light source. The control unit monitors the formation state of micropores with a diameter of 1 μm or less from the image acquired by the image sensor 341. Based on this monitoring result, the output and irradiation time of the laser light can be appropriately controlled.

[0069] A characteristic feature of the present invention is that the control unit 110 has a wavelength selection unit that selects the optimal laser wavelength according to the type and thickness of the material. Specifically, for example, the wavelength is selected under the following conditions: (1) For silicon substrates, a laser with a wavelength of 1064 nm is used. (2) For glass substrates, for plate thickness less than 1 mm: wavelength 266 nm For plate thickness of 1 mm or more and less than 3 mm: wavelength 355 nm The applicant has found that it is preferable to determine the above wavelength selection based on the condition that the laser transmittance of the material is 20% or more and less than 30%.

[0070] According to experiments conducted by the applicant, when the laser transmittance is 20% or less, most of the laser energy is absorbed at the material surface, resulting in excessive heat effects and melting at the surface, making it impossible to obtain fine machining accuracy. In particular, when forming micro-holes with a diameter of 1 μm or less, thermal deformation at the surface significantly reduces the roundness of the hole shape. On the other hand, when the laser transmittance is 30% or more, the laser energy is not sufficiently absorbed within the material, and the energy density at the focal point does not reach the machining threshold, making stable machining difficult. In this case, the variation in machining depth becomes large, and uniform deep drilling cannot be achieved.

[0071] On the other hand, in the range of laser transmittance between 20% and 30%, it is possible to ensure sufficient energy density at the focal point while suppressing excessive thermal effects on the material surface. In this transmittance range, efficient ablation processing at the focal point is possible while minimizing thermal effects on the surface, enabling the creation of fine holes with a high aspect ratio. In particular, when the focal point is set inside the material and processing is performed from there toward the surface, stable processing quality can be obtained in this transmittance range.

[0072] By setting the laser transmittance to an optimal range of 20% to 30%, high-quality micro-deep machining can be achieved. To meet this condition, it is important to select an appropriate laser wavelength according to the type and thickness of the material.

[0073] A key feature of the processing method of the present invention is that the laser's focal point is set inside the object, and processing is performed while moving the laser upwards from that point. This allows for efficient processing at the focal point while preventing unwanted surface cutting, for example, when using a 1064 nm wavelength laser on a silicon substrate.

[0074] This enables more efficient deep-cutting compared to conventional fixed-wavelength methods. In particular, when using a 1064 nm laser on a silicon substrate, deeper cuts are possible compared to using a 355 nm laser.

[0075] The control unit further has the function of determining the material of the workpiece from the image acquired by the image sensor 341. Specifically, it determines the differences in reflectivity and surface condition according to the material through image analysis and controls the output of the laser beam according to the determined material. This makes it possible to set optimal processing conditions for different materials such as silicon, glass, and ceramics.

[0076] The laser processing apparatus of this disclosure can also be used as a monitoring device to monitor the formation of metal wiring in micropores formed in a silicon substrate. The image sensor 341 allows observation of the metal deposition state inside the micropores and evaluation of the quality of the formed wiring. In particular, by employing a long-focus objective lens 31, it becomes possible to clearly observe or acquire images of the inside of deep micropores.

[0077] The applicant has previously proposed a laser processing apparatus capable of forming micro-holes smaller than 1 μm (e.g., 0.6 μm) on a Si wafer by utilizing the Gaussian distribution of laser light (Japanese Patent Publication No. 7511960).

[0078] The micro-microscope system of this disclosure has the feature of being able to grasp the processing status in real time by capturing the image magnified by the objective lens 31 with a CMOS sensor and displaying it on a monitor.

[0079] By adopting the micro-microscope system S of this disclosure in this laser processing apparatus, more precise processing becomes possible. The micro-microscope system of this disclosure achieves unprecedented traceability in position control at the nanometer level. In conventional technology, the accuracy of position control was only shown as theoretical or design values ​​based on tolerances, but this system makes it possible to visualize the actual position control in real time, or to detect the position in real time and directly verify its accuracy.

[0080] Specifically, by capturing a magnified image from a high-magnification objective lens 31 using a CMOS sensor and displaying it on a monitor, the position control status at the nanometer level can be confirmed in real time and directly. Alternatively, based on the image captured by the CMOS sensor, the control unit can grasp the position control status at the nanometer level in real time through image analysis. This system has an optical resolution of 18 nm per pixel, and the image data obtained at this resolution makes it possible to quantitatively evaluate the accuracy of position control as a measured value.

[0081] In conventional systems, control accuracy was estimated from the mechanical precision of the position control mechanism and theoretical values ​​of the electrical control system. However, this system allows for direct confirmation of repeatable position accuracy of approximately 20 nm as an actual observed image. This makes it possible to prove movement accuracy within ±90 nm not merely as a design value, but through actual measurement.

[0082] The key feature of this system is its ability to "visualize" position control. Visualizing the position of the controlled object at the nanometer level and obtaining its movement as a measured value provides a new indicator for quality assurance in microfabrication processes. In particular, by setting a minimum control resolution of 5 pixels or more, highly reliable position control is achieved while minimizing errors caused by image processing.

[0083] Thus, this system enables direct verification of position control accuracy based on actual measurements, rather than relying on indirect guarantees based on theoretical values ​​or tolerances. This realization of empirical traceability significantly contributes to improving quality control and manufacturing process reliability in nanometer-level microfabrication.

[0084] The microscopy system disclosed herein is equipped with a real-time alignment mechanism. This mechanism detects the three-dimensional coordinate positions of reference marks placed at the four corners of the substrate stage using image recognition, and performs position correction by dynamically comparing these positions with a theoretical displacement amount using a linear scale.

[0085] The alignment mechanism of this system has the following technical features. First, in detecting the position of the reference mark, unlike conventional two-dimensional alignment, it simultaneously acquires three-dimensional coordinates in the X-axis, Y-axis, and Z-axis directions. This acquisition of three-dimensional coordinates is achieved by image recognition using a high-magnification objective lens and a CMOS sensor, with a high spatial resolution of 18 nm.

[0086] Next, the difference between the detected real-world coordinate values ​​and the theoretical values ​​calculated using a linear scale is processed in real time. This calculation process calculates correction values ​​not only for the translational motion component of the stage but also for the rotational motion component. A particularly distinctive feature is that the correction algorithm also incorporates corrections for distortion of the projected image caused by positional displacement in the Z-axis direction.

[0087] Furthermore, the calculated correction values ​​are immediately reflected in the feedback control system. This feedback control achieves high-precision positioning accuracy of within ±90 nm while maintaining a repeatability accuracy of approximately 20 nm. The correction values ​​are applied not only as feedback to the stage drive mechanism but also as correction parameters for the image processing system.

[0088] A key feature of this system is its ability to perform these processes in real time. By executing the entire process, from detecting the position of the reference mark to applying correction values, in real time, it enables the maintenance of positional accuracy during continuous machining and observation. Furthermore, this correction process can adapt to positional deviations caused by changes in the material, shape, and environment of the workpiece.

[0089] This real-time alignment mechanism makes it possible to guarantee continuous positional accuracy in micro-machining, which was difficult with conventional technology. In particular, this system is effective in maintaining relative positional accuracy when forming multiple micro-holes and in ensuring alignment accuracy when machining at different depths.

[0090] One of the advantages of this laser processing device is its ability to perform maskless processing. For example, by using a 10 kHz high-frequency laser source, it is possible to irradiate the surface 10,000 times per second. When forming 10 μm processing holes in 20 shots, the processing time for one hole is approximately 0.002 seconds. This means that up to 150,000 holes can be processed in a comparable time to plasma etching (approximately 300 seconds per hole).

[0091] In the formation of internal electrodes in three-dimensional structures such as fine through-electrode structures, embedded wiring structures, and multilayer wiring structures with a diameter of 1 μm or less, for example, in TSVs (hereinafter, TSVs will be described as a representative example), conventional liquid plating makes it difficult to form uniform electrodes due to the influence of surface tension. Therefore, plating technology using gas and lasers is attracting attention as a new method. The micromicroscope system S of this disclosure is particularly effective for real-time monitoring and control in this plating process.

[0092] This system solves the following technical challenges during the plating process. First, it achieves synchronous alignment of the laser irradiation position and the gas supply position with a resolution of, for example, 18 nm during the gaseous plating material supply process. This enables localized deposition control of the plating material. Furthermore, by indirectly monitoring the spatial distribution of thermal energy due to laser irradiation through real-time optical observation, it achieves the formation of a uniform plating layer.

[0093] In particular, this system allows for simultaneous observation of both the front and back surfaces. This enables real-time monitoring of the metal deposition process inside the TSV from both ends of the through-hole. This simultaneous double-sided observation function makes it possible to continuously understand the plating formation state inside the TSV, which was not possible with conventional technology.

[0094] Furthermore, this system is equipped with the following control functions: During the plating layer formation process, it measures the thickness of the deposited metal at the nanometer level and dynamically controls the laser irradiation conditions and gas supply amount based on these measurement results. It also detects the uniformity of metal deposition on the inner wall of the TSV as a change in optical reflectivity and evaluates the quality of the formed electrode in real time.

[0095] Thus, this system functions not only as an inspection device in the plating process but also as a process control device. In particular, real-time monitoring and control during the plating layer formation process greatly contribute to improving yield and stabilizing quality in the formation of internal electrodes in micro-TSVs. In the final inspection process, it is also possible to quantitatively evaluate the surface properties and uniformity of the formed electrodes.

[0096] The application of this system makes it possible to form high-quality internal electrodes in micro TSVs with a diameter of 1 μm or less, which was previously considered difficult. This represents an important technological breakthrough toward further miniaturization and density increases in three-dimensional packaging technology.

[0097] Furthermore, the micro-microscope system S of this disclosure is also useful in processes such as chip mounting onto wafers and stacking wafers together. The image inspection technology of this system can be utilized for the high-precision alignment required when forming small-diameter through-holes.

[0098] Furthermore, the micromicroscope system S disclosed herein can also be applied to semiconductor photoprocessing. By utilizing an in-plane accuracy of ±80 nm and a depth of field of 1 μm, improved parallelism between the mask and the workpiece can be achieved. Specifically, the height in the Z-axis direction is adjusted in 1 μm increments using the 1 μm depth of field, and the tilt angle of the workpiece is precisely controlled while the mask is held by an electrostatic chuck. This makes it possible to control the tilt angle in addition to adjusting in the XY direction, achieving more precise positioning. In addition, the use of an electrostatic chuck makes it possible to use the system inside a vacuum chamber.

[0099] The micro-microscope system S disclosed herein enables high-precision position control and real-time monitoring of the processing state in the semiconductor device manufacturing process, particularly in the laser trimming process. This system has an in-plane accuracy of ±80 nm and a depth of field of 1 μm, and by utilizing these optical characteristics, it enables precise laser trimming control that was difficult to achieve with conventional technology.

[0100] The following are some of the distinctive control functions of this system in laser trimming. First, the electrostatic chuck mechanism ensures stable positioning within the vacuum chamber. This electrostatic chuck mechanism minimizes thermal expansion and mechanical distortion of the workpiece while enabling fine position adjustment in the XY direction and precise control of the tilt angle.

[0101] In particular, this system employs a unique control method for the three-dimensional positioning of wiring and other components to be trimmed. By utilizing a depth of field of 1 μm to adjust the height in the Z-axis direction in 1 μm increments, and simultaneously precisely controlling the tilt angle of the workpiece, the laser irradiation position is optimized. This control prevents a decrease in processing accuracy caused by variations in thickness and surface irregularities of the trimmed material.

[0102] The most important feature of this system is its real-time monitoring function during laser trimming. It is possible to continuously observe the cutting state of the trimming target with a spatial resolution of, for example, 18 nm, and dynamically control the laser power and irradiation time based on these observations. This ensures reliable separation of defective areas while minimizing excessive cutting and thermal effects on surrounding areas.

[0103] Furthermore, this system includes the following trimming control functions: a function to automatically select the optimal laser irradiation conditions according to the material and film thickness to be trimmed; a function to optically confirm the conductivity state after trimming; and a function to evaluate the heat-affected zone around the cut area. These functions improve the reliability and reproducibility of the trimming process.

[0104] In addition, this system is capable of continuous trimming of multiple defective areas. With a repeatable positional accuracy of approximately 20 nm, it achieves high-speed continuous processing while maintaining relative positional accuracy between multiple trimming locations. During this process, the processing status of each trimming location can be recorded as data and used as evidence for quality assurance in subsequent processes.

[0105] Thus, the application of this system improves positioning accuracy, stabilizes processing quality, and increases processing speed in the laser trimming process. This represents a significant technological advancement that directly contributes to improving semiconductor device yield and reducing manufacturing costs.

[0106] A method for manufacturing an electronic device using the laser processing apparatus of this disclosure is described below.Hereinafter, when "observation" is written, for example, observation includes observation by a human and image recognition by a control unit based on image processing of the image.In this manufacturing method, the surface of the workpiece is constantly observed by an image sensor 341, and laser light from a laser light source 39 is irradiated to form micropores.The shape of the formed micropores is confirmed in real time by the image sensor 341, and the processing accuracy is guaranteed.

[0107] In particular, this manufacturing method is extremely effective in forming microholes that penetrate silicon substrates, such as TSVs. Since the image sensor 341 allows simultaneous observation of both the inlet and outlet sides of the TSV, the laser irradiation conditions can be optimally controlled while confirming the formation state of the through-hole in real time.

[0108] Furthermore, this manufacturing method can also be applied to forming a plating layer in micropores. When forming a plating layer by irradiating with laser light while supplying gaseous plating material, the image sensor 341 monitors the formation state of the plating layer. This makes it possible to form a uniform plating layer.

[0109] Furthermore, this manufacturing method also supports the formation of micro-holes in substrates where different materials are laminated. The image sensor 341 detects the boundaries between materials, and the laser irradiation conditions are appropriately changed according to the detected material. This prevents processing defects caused by differences in materials.

[0110] In this manufacturing method, when forming multiple micropores, the formation state of each micropore is sequentially checked using an image sensor 341, and the results are recorded as quality control data. The recorded data is used for quality assurance in the manufacturing process. In particular, it is effective in ensuring uniformity of quality in mass production processes and in investigating the causes of defects.

[0111] The laser processing apparatus using the micromicroscope system S of this disclosure is equipped with a special alignment mechanism to achieve high-precision position control. The control unit detects the three-dimensional coordinate positions of reference marks placed at the four corners of the stage 36 using an image sensor 341. The detected coordinate positions are compared with the theoretical amount of movement using a linear scale, and position correction is performed based on the difference.

[0112] Alignment control by the control unit is performed in the following procedure. First, correction values ​​for the translational and rotational motion components of the stage 36 are calculated from the three-dimensional coordinate position of the reference mark. The calculated correction values ​​are reflected in the feedback control system in real time, achieving extremely high positioning accuracy within ±90 nm. In particular, height information to the reference mark is acquired by the image sensor 341, and the focal position of the laser beam is adjusted in 1 μm increments based on this information to ensure three-dimensional positional accuracy.

[0113] Furthermore, the control unit has a function to detect material boundaries of the workpiece from the density changes of the image acquired by the image sensor 341. This function allows the system to automatically recognize material boundaries even in structures where different materials such as silicon, metal, and insulators are layered, and to automatically switch to the optimal laser irradiation conditions for each material.

[0114] Furthermore, the control unit uses an image sensor 341 to detect the thermal effects around the processing area caused by laser irradiation, and controls the laser irradiation time based on this information. This makes it possible to minimize thermal effects on the surrounding area while maintaining processing accuracy.

[0115] The laser processing apparatus disclosed herein also has a function to record and store image data showing the formation state of micro-holes. This image data can be used as evidence of processing quality and contributes to improving the traceability of the manufacturing process. In particular, when forming a large number of micro-holes in succession, it becomes possible to track the processing state of each individual hole in chronological order, contributing to improved reliability of quality control.

[0116] The information processing device 1 included in the micromicroscope system S of this disclosure will now be described. Figure 19 is a block diagram showing an example of the hardware configuration of the information processing device 1 included in the micromicroscope system S shown in Figure 1, which is not shown in Figure 1.

[0117] The information processing device 1 comprises a CPU (Central Processing Unit) 11, a ROM (Read Only Memory) 12, a RAM (Random Access Memory) 13, a bus 14, an input / output interface 15, an input unit 16, an output unit 17, a storage unit 18, a communication unit 19, and a drive 20.

[0118] The CPU 11 executes various processes according to the program recorded in the ROM 12 or the program loaded into the RAM 13 from the storage unit 18. The RAM 13 also stores data and other information necessary for the CPU 11 to execute various processes.

[0119] The CPU 11, ROM 12, and RAM 13 are interconnected via a bus 14. An input / output interface 15 is also connected to this bus 14. An input / output interface 15 is connected to an input unit 16, an output unit 17, a storage unit 18, a communication unit 19, and a drive 20.

[0120] The input unit 16 is configured, for example, with a keyboard, and takes various types of information. The output unit 17 is configured with a display such as an LCD or a speaker, and outputs various types of information as images or sounds. The storage unit 18 is configured with DRAM (Dynamic Random Access Memory) or the like, and stores various types of data. The communication unit 19 connects to the internet, for example.

[0121] A removable media 21, such as a magnetic disk, optical disk, magneto-optical disk, or semiconductor memory, is appropriately mounted on the drive 20. Programs read from the removable media 21 by the drive 20 are installed in the storage unit 18 as needed. The removable media 21 can also store various data stored in the storage unit 18, just like the storage unit 18.

[0122] Figure 20 is a functional block diagram showing an example of the functional configuration of an information processing device 1 according to one embodiment applied to the micromicroscope system S of Figure 1. The information processing device 1 performs input and output of sensor signals and control signals, etc., with the revolving nose 32, imaging unit 34, stage 36, microscope tube vertical adjustment unit 37, and laser light source 39 via the input / output interface 15.

[0123] As shown in Figure 20, the CPU 11 of the information processing device 1 functions as follows: an image acquisition unit 111, a processing condition determination unit 112, a position control unit 113, a laser output control unit 114, and a machine learning unit 115.

[0124] The image acquisition unit 111 acquires surface image data of the object to be observed, obtained by the image sensor 341, and outputs the acquired image data to the processing condition determination unit 112 and the position control unit 113. The acquired image data includes shape and pattern information of the wiring and electrodes to be subjected to maskless processing or trimming.

[0125] The processing condition determination unit 112 analyzes the material, surface condition, and shape of the object to be observed from the image data input from the image acquisition unit 111, and determines the processing parameters necessary for laser processing based on the analysis results. The processing parameters include the laser light output, irradiation time, laser light pulse width, repetition frequency, and irradiation position. The processing condition determination unit 112 detects the material boundaries of the wiring or electrodes to be maskless processed or trimmed, and automatically sets the optimal laser irradiation conditions according to the detected material.

[0126] The position control unit 113 detects the three-dimensional coordinates of the object to be observed from the image data input from the image acquisition unit 111, and controls the positions of the stage 36 and the laser light source 39 based on the detected coordinate information. The position control unit 113 achieves processing position control with an accuracy of ±50 nm. In particular, height information to the reference mark is acquired by the image sensor 341, and the focal position of the laser beam is adjusted in units of 1 μm based on this information to ensure three-dimensional position accuracy.

[0127] The laser output control unit 114 controls the output of laser light from the laser light source 39 based on the processing parameters determined by the processing condition determination unit 112. By controlling the pulse width, pulse energy, and repetition frequency, the laser output control unit 114 achieves nanometer-level microfabrication.

[0128] The machine learning unit 115 learns the correlation between the image data before and after processing acquired by the image acquisition unit 111, the processing parameters determined by the processing condition determination unit 112, and the processing result, thereby contributing to the improvement of processing accuracy. The machine learning unit 115 optimizes the processing conditions using a deep learning algorithm.

[0129] The image acquisition unit 111 and the processing condition determination unit 112 work together to detect material boundaries of the object being observed and automatically set optimal processing conditions for different materials. The position control unit 113 and the laser output control unit 114 synchronize the control of the processing position and the adjustment of the laser output to achieve precise micro-machining.

[0130] Each of these functional units is implemented on computer hardware, including a processor and memory, and is realized by the processor executing a program stored in memory. These functional units work together in real time to achieve maskless machining and laser trimming processes with a machining accuracy of 80 nm or less.

[0131] Although one embodiment of the present invention has been described above, the present invention is not limited to the embodiments described above, and any modifications, improvements, etc. that can achieve the objectives of the present invention are considered to be included in the present invention.

[0132] In summary, the micromicroscope system S to which the present invention is applied only needs to have the following configuration, and various embodiments can be taken.

[0133] (1) The micromicroscope system S comprises an objective lens 31 that captures light from a sample, and an image sensor 341 that captures an image of the light captured by the objective lens 31, wherein the pixel size of the image sensor 341 is in the range of 1 μm to 4 μm, and a microlens 3413 corresponding one-to-one with each pixel is provided at the light-receiving position of the image sensor, and the resolution of the microlens 3413 is in the range of 1.20 times or more and 2.20 times or less the resolution of the objective lens 31. As a result, it is possible to achieve resolution performance close to that of a SEM, even though it is an optical microscope.

[0134] (2) The micromicroscope system S further includes an imaging lens 381 that forms an image on the image sensor 341 of the light captured by the objective lens 31, and the resolution of the imaging lens 381 may be 3.5 times or more the resolution of the microlens 3413 and 50 times or less the resolution of the objective lens 31. This eliminates factors that reduce the resolution.

[0135] (3) In addition, in the micromicroscope system S, the pixel size of the image sensor 341 may be in the range of 1.5 μm to 3 μm. This makes it possible to obtain imaging results that fall within the range of good SEM.

[0136] (4) The micromicroscope system S further comprises a stage 36 on which a sample is placed, and the horizontality of the stage 36 may be such that the maximum height difference of the stage 36 in a 100 mm square area is 14 μm or less. This makes it possible to achieve a repeatability of 80 nm.

[0137] (5) In addition, in the micromicroscope system S, the cutting accuracy as the flatness of the stage 36 may be 5 μm or less in a 100 mm square of the stage 36. This makes it possible to set the repeatability to 80 nm or less.

[0138] (6) The micromicroscope system S may also include an optical system with a depth of field of 1 μm and a stage 36 with a tilt adjustment function. This makes it possible to achieve a repeatability of 80 nm or less.

[0139] (7) A laser processing apparatus may be provided with a laser light source 39 and the above-described micromicroscope system S. This makes it possible to irradiate a precise micro-area with laser light by taking advantage of the 80 nm resolution.

[0140] (8) The micromicroscope system S may also include a control unit 110 that irradiates a sample with laser light from the laser light source 39 via the objective lens 31 and controls the irradiation position of the laser light based on the image acquired by the image sensor 341. This allows for appropriate control of the laser irradiation position.

[0141] (9) In addition, in the micromicroscope system S, the control unit 110 may detect the position of the workpiece from the image acquired by the image sensor 341 and control the irradiation position of the laser beam with an accuracy of ±90 nm or less based on the detected position information. This makes it possible to achieve highly accurate positioning processing.

[0142] (10) In addition, in the micromicroscope system S, the control unit 110 may detect the three-dimensional shape of the workpiece from the image acquired by the image sensor 341 and control the focus position of the laser beam based on the detected three-dimensional shape. This makes it possible to achieve an optimal machining depth according to the surface shape of the workpiece.

[0143] (11) In addition, in the micromicroscope system S, the laser light source 39 may output laser light with a wavelength of 355 nm, and the control unit 110 may monitor the formation state of micropores with a diameter of 1 μm or less from the image acquired by the image sensor 341. This makes it possible to check the state of fine processing in real time.

[0144] (12) In addition, in the micromicroscope system S, the control unit 110 may determine the material of the workpiece from the image acquired by the image sensor 341 and control the output of the laser light from the laser light source 39 according to the determined material. This makes it possible to automatically set the optimal processing conditions according to the material.

[0145] (13) In addition, in the micromicroscope system S, the control unit 110 may use the image sensor 341 to detect the three-dimensional coordinate positions of reference marks placed at the four corners of the stage 36 on which the sample is placed, in order to maintain the relative positional accuracy of the multiple micropores formed in the workpiece, and perform position correction by calculating the difference between the detected coordinate positions and the theoretical amount of movement according to the linear scale. This makes it possible to maintain the positional accuracy of the multiple micropores with high precision.

[0146] (14) In addition, in the micromicroscope system S, the control unit 110 may calculate correction values ​​for the translational and rotational motion components of the stage 36 from the three-dimensional coordinate position of the reference mark, and reflect the calculated correction values ​​in the feedback control system to achieve a positioning accuracy of within ±90 nm. This makes it possible to achieve ultra-high precision positioning at the nanometer level.

[0147] (15) In addition, in the micromicroscope system S, the control unit 110 may acquire height information from the image acquired by the image sensor 341 to a reference mark, and adjust the focal position of the laser beam from the laser light source 39 in units of 1 μm based on the acquired height information. This makes it possible to achieve accurate focal position control according to the surface shape of the workpiece.

[0148] (16) In addition, in the micromicroscope system S, the control unit 110 may detect material boundaries of the workpiece from the density changes of the image acquired by the image sensor 341, and automatically switch the irradiation conditions of the laser light from the laser light source 39 based on the detected material boundaries. This makes it possible to automatically set the optimal processing conditions for workpieces containing a mixture of different materials.

[0149] (17) In addition, in the micromicroscope system S, the control unit 110 may detect the thermal effect around the processing area due to laser irradiation from the image acquired by the image sensor 341 and control the irradiation time of the laser light from the laser light source 39 based on the detected thermal effect. This makes it possible to achieve precise processing while minimizing the thermal effect on the surroundings.

[0150] (18) In addition, in the micromicroscope system S, the control unit 110 may record image data showing the formation state of micropores acquired by the image sensor 341 and save the recorded image data as an indicator of processing quality. This ensures traceability of the processing process and improves the reliability of quality control.

[0151] (19) Furthermore, a monitoring device for monitoring the formation of metal wiring in micropores formed in a silicon substrate uses the laser processing apparatus described in (8) and acquires the metal deposition state inside the micropores using the image sensor. This makes it possible to adjust the laser processing conditions based on the metal deposition state inside the micropores.

[0152] (20) In addition, in the micromicroscope system S, the laser processing apparatus may be used to form micropores by irradiating the surface of the workpiece with laser light from the laser light source 39 while observing the surface of the workpiece with the image sensor 341, and the shape of the formed micropores may be confirmed with the image sensor 341. This ensures that high-quality micro-processing can be reliably achieved.

[0153] (21) In addition, in the micromicroscope system S, a TSV (Through Silicon Via) is formed through the silicon substrate, and the irradiation conditions of the laser light from the laser light source 39 are controlled while simultaneously observing both the entrance and exit sides of the PIV using the image sensor 341. This makes it possible to achieve optimal processing while checking the formation state of the through hole in real time.

[0154] (22) In addition, in the micromicroscope system S, after the formation of the micropores, a plating layer may be formed by supplying gaseous plating material and irradiating it with laser light from the laser light source 39, and the formation state of the plating layer may be monitored by the image sensor 341. This makes it possible to form a uniform plating layer.

[0155] (23) In addition, when forming microholes in a substrate made of laminated different materials using the micromicroscope system S, the boundary between materials may be detected by the image sensor 341, and the irradiation conditions of the laser light from the laser light source 39 may be changed according to the detected material. This makes it possible to prevent processing defects due to differences in material.

[0156] (24) In addition, when forming multiple micropores in the micromicroscope system S, the formation state of each micropore may be sequentially checked with the image sensor 341, and the check results may be recorded as quality control data. This can contribute to quality control and yield improvement in the processing process.

[0157] (25) The micromicroscope system S also includes an information processing device, which comprises an image acquisition unit 111, a processing condition determination unit 112, a position control unit 113, a laser output control unit 114, and a machine learning unit 115. The image acquisition unit 111 acquires and outputs image data of the surface of the object to be observed acquired by the image sensor 341. The processing condition determination unit 112 analyzes the material, surface condition, and shape of the object to be observed from the image data to determine processing parameters. The position control unit 113 detects the three-dimensional coordinates of the object to be observed from the image data and controls the irradiation position of the laser beam. The laser output control unit 114 controls the output of the laser beam from the laser light source 39 based on the processing parameters. The machine learning unit 115 may learn the correlation between image data, processing parameters, and processing results. This enables precise processing control based on advanced image processing and machine learning.

[0158] (26) In addition, in the micromicroscope system S, the processing condition determination unit 112 may detect material boundaries of wiring and electrodes to be trimmed from the image data and automatically set the irradiation conditions of the laser light source 39 according to the detected material. This makes it possible to automatically set the optimal processing conditions according to the difference in material.

[0159] (27) In addition, in the micromicroscope system S, the position control unit 113 may adjust the focal position of the laser beam in units of 1 μm based on the height information acquired by the image sensor 341. This makes it possible to achieve highly accurate focal position control.

[0160] (28) In addition, in the micromicroscope system S, the laser output control unit 114 may achieve nanometer-level microfabrication by controlling the pulse width, pulse energy, and repetition frequency. This enables ultrafine processing with high precision.

[0161] (29) In addition, in the micromicroscope system S, the position control unit 113 and the laser output control unit 114 may synchronize the control of the processing position and the adjustment of the laser output to achieve a processing accuracy of 80 nm or less. This makes it possible to stably perform extremely high-precision processing.

[0162] (30) In addition, in the micromicroscope system S, the machine learning unit 115 may optimize the processing conditions using a deep learning algorithm and provide the optimized processing parameters to the processing condition determination unit 112. This makes it possible to achieve continuous improvement and optimization of the processing conditions.

[0163] (31) In addition, in the laser processing apparatus, a wavelength may be selected for the laser light source such that the absorption rate of the sample to be processed is 20% or more and 30% or less. This makes it possible to achieve more efficient deep cutting compared to the fixed wavelength method. In particular, when a laser with a wavelength of 1064 nm is used for a silicon substrate, deeper cutting is possible compared to a laser with a wavelength of 355 nm.

[0164] S...Microscope system, 1...Information processing device, 31...Objective lens, 32...Revolving nosepiece, 33...Microscope tube, 34...Imaging unit, 341...Image sensor, 3411...Pixel, 3412...Microlens, 3413...Photodiode, 3414...Photodiode, 35...Expansion mount, 36...Stage, 361...Stepping motor, 37...Microscope tube vertical adjustment unit, 38...Infinity correction optical system, 381...Imaging lens, 39...Laser light source

Claims

1. A micromicroscope system comprising: an objective lens for capturing light from a sample; and an image sensor for capturing an image of the light captured by the objective lens, wherein the pixel size of the image sensor is in the range of 1.0 μm to 4.0 μm, and a microlens corresponding one-to-one with each pixel is provided at the light-receiving position of the image sensor, and the resolution of the microlens is in the range of 1.20 times or more and 2.20 times or less the resolution of the objective lens.

2. The microscope system according to claim 1, further comprising an imaging lens that forms an image of the light captured by the objective lens onto the image sensor, wherein the resolution of the imaging lens is 3.5 times or more the resolution of the microlens and 50 times or less the resolution of the objective lens.

3. The micromicroscope system according to claim 1, wherein the pixel size of the image sensor is in the range of 1.5 μm to 3.0 μm.

4. The micromicroscope system according to claim 1, further comprising a stage for placing a sample, wherein the horizontality of the stage is such that the maximum height difference over a 100 mm square of the stage is 14 μm or less.

5. The micromicroscope system according to claim 4, wherein the cutting accuracy as the flatness of the stage is 5 μm or less in a 100 mm square of the stage.

6. The micromicroscope system according to claim 4, wherein the stage has a tilt adjustment function and an optical system with a depth of field of 1 μm.

7. A laser processing apparatus comprising a laser light source and the micromicroscope system described in claim 1.

8. The laser processing apparatus according to claim 7, wherein the wavelength of the laser light source is selected such that the absorption rate in the sample to be processed is 20% or more and 30% or less.

9. The laser processing apparatus according to claim 7, further comprising a control unit that irradiates a sample with laser light from the laser light source through the objective lens and controls the irradiation position of the laser light based on an image acquired by the image sensor.

10. The laser processing apparatus according to claim 9, wherein the control unit detects the position of the workpiece from the image acquired by the image sensor and controls the irradiation position of the laser beam with an accuracy of ±90 nm or less based on the detected position information.

11. The laser processing apparatus according to claim 9, wherein the control unit detects the three-dimensional shape of the workpiece from the image acquired by the image sensor and controls the focus position of the laser beam based on the detected three-dimensional shape.

12. The laser processing apparatus according to claim 11, wherein the laser light source outputs laser light with a wavelength of 355 nm, and the control unit monitors the formation state of micropores with a diameter of 1 μm or less from an image acquired by the image sensor.

13. The laser processing apparatus according to claim 9, wherein the control unit determines the material of the workpiece from the image acquired by the image sensor and controls the output of the laser light according to the determined material.

14. The laser processing apparatus according to claim 9, wherein the control unit detects the three-dimensional coordinate positions of reference marks placed at the four corners of the stage on which the sample is placed using the image sensor, in order to maintain the relative positional accuracy of a plurality of micro-holes formed in the workpiece, and performs position correction by calculating the difference between the detected coordinate positions and the theoretical amount of movement using a linear scale.

15. The laser processing apparatus according to claim 14, wherein the control unit calculates correction values ​​for the translational and rotational motion components of the stage from the three-dimensional coordinate position of the reference mark, and reflects the calculated correction values ​​in the feedback control system to achieve a positioning accuracy of within ±90 nm.

16. The laser processing apparatus according to claim 9, wherein the control unit acquires height information from the image acquired by the image sensor to a reference mark, and adjusts the focal position of the laser beam in units of 1 μm based on the acquired height information.

17. The laser processing apparatus according to claim 9, wherein the control unit detects the material boundary of the workpiece from the density change of the image acquired by the image sensor, and automatically switches the irradiation conditions of the laser light based on the detected material boundary.

18. The laser processing apparatus according to claim 9, wherein the control unit detects the thermal effect around the processing area caused by laser irradiation from the image acquired by the image sensor, and controls the irradiation time of the laser light based on the detected thermal effect.

19. The laser processing apparatus according to claim 9, wherein the control unit records image data indicating the formation state of micropores acquired by the image sensor, and stores the recorded image data as evidence of processing quality.

20. A monitoring device for monitoring the formation of metal wiring in micropores formed in a silicon substrate, characterized in that it uses the laser processing apparatus described in claim 7 and acquires the metal deposition state in the micropores using the image sensor.

21. A method for manufacturing an electronic device having micropores, comprising: using the laser processing apparatus described in claim 7, irradiating with laser light from the laser light source to form micropores, and confirming the shape of the formed micropores with the image sensor.

22. The method for manufacturing an electronic device according to claim 21, wherein the microholes are TSVs (Through Silicon Vias) penetrating the silicon substrate, and the irradiation conditions of the laser light are controlled while simultaneously observing both the inlet and outlet sides of the TSV using the image sensor.

23. The method for manufacturing an electronic device according to claim 21, wherein, after the formation of the micropores, a plating layer is formed by irradiating the laser light while supplying a gaseous plating material, and the formation state of the plating layer is monitored by the image sensor.

24. The method for manufacturing an electronic device according to claim 21, wherein, when forming micro-holes in a substrate in which different materials are laminated, the boundary between materials is detected by the image sensor, and the irradiation conditions of the laser light are changed according to the detected material.

25. The method for manufacturing an electronic device according to claim 21, wherein, when forming multiple micropores, the formation state of each micropore is sequentially checked with the image sensor and the check results are recorded as quality control data.

26. A micromicroscope system equipped with an information processing device, wherein the information processing device comprises an image acquisition unit, a processing condition determination unit, a position control unit, a laser output control unit, and a machine learning unit, the image acquisition unit acquires and outputs image data of the surface of an object to be observed acquired by the image sensor, the processing condition determination unit analyzes the material, surface condition, and shape of the object to be observed from the image data to determine processing parameters, the position control unit detects the three-dimensional coordinates of the object to be observed from the image data to control the irradiation position of the laser beam, the laser output control unit controls the output of laser beam from the laser light source based on the processing parameters, and the machine learning unit learns the correlation between image data, processing parameters, and processing results, as described in claim 1.

27. The micromicroscope system according to claim 26, wherein the processing condition determination unit detects material boundaries of wiring and electrodes to be trimmed from the image data and automatically sets the laser light irradiation conditions according to the detected material.

28. The micromicroscope system according to claim 26, wherein the position control unit adjusts the focal position of the laser beam in units of 1 μm based on height information acquired by the image sensor.

29. The micromicroscope system according to claim 26, wherein the laser output control unit enables nanometer-level microfabrication by controlling the pulse width, pulse energy, and repetition frequency.

30. The micromicroscope system according to claim 26, wherein the position control unit and the laser output control unit synchronize the control of the processing position and the adjustment of the laser output to achieve a processing accuracy of 80 nm or less.

31. The micromicroscope system according to claim 26, wherein the machine learning unit optimizes the processing conditions using a deep learning algorithm and provides the optimized processing parameters to the processing condition determination unit.

Images