High-aspect-ratio micro-hole inspection system and method using optical frequency multiplication technology

Abstract

This invention provides a high-aspect-ratio micro-hole inspection system and method using optical frequency multiplication technology. [Solution] The above micropores include, but are not limited to, through-silicon vias (TSV), through-glass vias (TGV), and through-SiC vias (TSiCV). By scanning fundamental frequency light of a specific wavelength along the axis of the micropore, the interface between the micropore and other materials (including, but not limited to, air) is excited, generating an intense interface-enhanced frequency multiplication signal. This allows for the acquisition of high-resolution and visualized micropore geometric structure images. The shape and appearance of the micropores can be directly observed from these images, or their quality can be judged. Furthermore, the frequency multiplication signal can be analyzed, enabling high-precision measurement of micropore size, shape, surface roughness, or the determination of defects and cracks, and can be applied to the manufacturing process control and quality control of high-aspect-ratio micropores.

Description

Technical Field

[0001] The present invention claims that the invention application No. 113143875 is the basic application for domestic priority of this case. The present invention is an optical inspection technology, and particularly refers to an optical inspection system and method capable of inspecting high aspect ratio micro holes (including, but not limited to, Through Silicon Via (TSV), Through-Glass Via (TGV), and Through-SiC Via (TSiCV)).

Background Art

[0002] Conventional TSV (Through Silicon Via) optical measurement technologies utilize optical principles to perform non-destructive measurements on parameters such as the size, shape, and depth of TSVs. Conventional TSV optical measurement technologies mainly include the following several types.

[0003] Optical microscope: Using a high-magnification optical microscope to directly observe the shape and appearance of TSVs, and obtaining size information by visual inspection or auxiliary measurement software.

[0004] Interferometry: By utilizing the interference phenomenon of light, the depth and surface roughness of TSVs are measured. Commonly seen interferometry methods include white light interference, phase shift interference, etc.

[0005] Confocal microscope: Scanning the sample surface using a focused light beam, and reconstructing the three-dimensional image of the sample by detecting the returned optical signal.

[0006] Optical profiler: Utilizing the principle of optical triangulation to measure the light reflection angles at different positions on the sample surface, and obtaining the height information of the sample.

[0007] Conventional TSV optical measurement techniques are widely used in semiconductor manufacturing, but they do have some limitations. In particular, conventional optical measurement has certain limitations when it comes to specific needs.

[0008] Prior art Chinese Patent Application Publication No. 106403808 discloses an apparatus and method for measuring the shape and appearance of a silicon through-electrode, which is, An infrared laser light source used to provide illumination, A lighting unit used to adjust the above-mentioned illumination luminous flux and to irradiate the etched or non-etched surface of the silicon through-electrode to be measured, An imaging detection unit used to detect the diffraction angle spectral signal generated when the above illumination beam is irradiated onto the surface or back surface of the silicon through-electrode of the object to be measured, A processing unit used to acquire shape and appearance data of the silicon through-electrode to be measured based on the above diffraction angle spectral signal, Includes.

[0009] Prior art, Taiwan Patent No. I807653, discloses an optical measurement system for high aspect ratio microstructures, which includes a light source module, an optical lens group, and a spatial modulation element. The above light source module has a first characteristic size, thereby generating detection light having a first divergence angle. The above optical lens group receives the above detection light and projects the above detection light onto the object to be measured. The spatial modulation element described above is installed between the light source module and the optical lens group. The spatial modulation element has an aperture of a second characteristic size, and the detected light passing through the center of the aperture has a second divergence angle. In this configuration, the product of the first characteristic size and the first divergence angle approximates or is equal to the product of the second characteristic size and the second divergence angle. [Prior art documents] [Patent Documents]

[0010] [Patent Document 1] Chinese Patent Application Publication No. 106403808 Specification [Patent Document 2] Taiwan Patent No. I807653 [Overview of the project] [Problems that the invention aims to solve]

[0011] The present invention provides an innovative high-aspect-ratio micropore inspection method based on the principle of interface-enhanced frequency multiplication signals. The micropores include, but are not limited to, through-silicon vias (TSV), through-glass vias (TGV), and through-silicon vias (TSiCV). By scanning a specific wavelength of fundamental frequency light along the axis of the micropore, the interface between the micropore and other materials (including, but not limited to, air) is excited, generating an intense interface-enhanced frequency multiplication signal. This allows for the acquisition of high-resolution and visualized micropore geometric structure images. These images exhibit a high-intensity and clear interface-enhanced frequency multiplication signal along the pore shape, allowing for direct observation of the micropore's shape and appearance, or assessment of its quality. Furthermore, the frequency multiplication signal can be analyzed, enabling highly accurate measurements of micropore size, shape, surface roughness, or the detection of defects and cracks. This technology is applicable to manufacturing process control and quality management of high-aspect-ratio micropores and has broad applicability. [Means for solving the problem]

[0012] The technical features of the present invention are as follows.

[0013] A high aspect ratio micro-hole inspection system using optical frequency multiplication technology, comprising the following:

[0014] The fundamental frequency light is used to scan the sample being measured along the X and Y axes, and also to enter and scan the micropores of the sample along the Z axis.

[0015] A photodetector that receives an optical signal generated when the above-mentioned fundamental frequency light scans the above-mentioned micropores and is used to convert the frequency-doubled signal of the above-mentioned optical signal into an electrical signal.

[0016] A signal processing and image module that is coupled to the above-mentioned photodetector, acquires and processes the above-mentioned electrical signal, and is used to generate an image related to the micropore geometry. The above-mentioned micropore geometry image has a high-intensity and clear interface-enhanced frequency-doubled signal at the interface where the micropore contacts other materials.

[0017] A method for inspecting high aspect ratio micropores using optical frequency doubling technology, including the following steps.

[0018] Provide fundamental frequency light of a specific wavelength, and the above-mentioned fundamental frequency light has sufficient energy to excite the interface between the micropores and other materials of the sample to be measured and generate a frequency-doubled signal.

[0019] Perform a light beam scanning procedure along the axial direction of the micropores of the above-mentioned sample to be measured, and the above-mentioned scanning procedure ensures that the fundamental frequency light can scan to the interface where the micropores contact other materials.

[0020] Capture the above-mentioned frequency-doubled signal and generate a high-resolution micropore geometry image. The above-mentioned micropore geometry image has a high-intensity and clear interface-enhanced frequency-doubled signal at the interface between the micropores and other materials, and clearly shows the characteristics and defects of the structure of the above-mentioned micropores.

Brief Description of the Drawings

[0021] [Figure 1] A schematic diagram of the system of the present invention. [Figure 2] Example 1 of the micropore geometry image of the present invention. [Figure 3] Example 2 of the micropore geometry image of the present invention. [Figure 4] An image of the micropore geometric cross-section at the top of FIG. 3.

Embodiments for Carrying Out the Invention

[0022] The method of implementing the present invention will be described below with reference to the attached figures and examples. It should be noted in advance that the figures provided in the following examples merely illustrate the basic concept of the present invention in a schematic manner, and only show the components related to the present invention within the diagrams, and are not drawn based on the number, shape, and size of the parts when actually implementing the invention.

[0023] The micropores mentioned below include, but are not limited to, through-silicon vias (TSVs), through-glass vias (TGVs), and through-silicon carbide vias (TSiCVs). [Examples]

[0024] The present invention's high-aspect-ratio micropore inspection method utilizes optical frequency multiplication technology to excite the interface between the micropore and other materials (including, but not limited to, air) by scanning a fundamental frequency light of a specific wavelength along the micropore axis, generating an intense interface-enhanced frequency multiplication signal. This allows for the acquisition of a high-resolution and visualized micropore geometric structure image. The image has a high-intensity and clear interface-enhanced frequency multiplication signal along the pore shape, allowing for direct observation of the shape and appearance of the micropore or determination of its quality.

[0025] As shown in Figure 1, according to the method described above, the high aspect ratio micro-hole inspection system of the optical frequency multiplication technology of the present invention includes a fundamental frequency light 10, a galvanometer scanner system 20, a photodetector 30, and a signal processing and image module 40.

[0026] The wavelength range of the above-mentioned fundamental frequency light 10 is 1200 nm to 1800 nm, and includes, but is not limited to, an ultrafast laser with an infrared wavelength of 1560 nm. The above-mentioned fundamental frequency light 10 scans along the X and Y axes of the sample to be measured 51, and also enters and scans inside the micropores 50 of the sample to be measured 51 along the Z axis.

[0027] The galvanoscanner system 20 described above includes, but is not limited to, a combination of a beam expander 21, an attenuator 22, a first lens 23, a galvano mirror 24, and a second lens 25 arranged along the direction of the fundamental frequency light 10. The galvanoscanner system 20 is used to adjust the single-point fundamental frequency light 10 into a scanning fundamental frequency light.

[0028] The beam expander 21 controls the luminous flux size and divergence angle of the fundamental frequency light 10 to predetermined parameters or their range values.

[0029] The attenuator 22 is used to reduce the power of the fundamental frequency light 10 to a predetermined parameter or a range value, thereby protecting the sample 51 being measured and preventing damage caused by excessively high energy.

[0030] The first lens 23 described above is used to focus the fundamental frequency light 10 that has passed through the attenuator 22 onto the galvanometer mirror 24.

[0031] The galvanometer mirror 24 is a highly reflective mirror installed on the rotation axis. The drive circuit provides the drive voltage and control signal required by the galvanometer mirror 24, and by precisely and accurately controlling the rotation speed and angle of the galvanometer mirror 24, precise and accurate X-axis and Y-axis scanning is performed.

[0032] The second lens 25 described above is used to focus the fundamental frequency light 10 transmitted through the galvanometer mirror 24 onto the X and Y axis work surfaces of the sample 51 to be measured, where the micropores 50 are located.

[0033] The photodetector 30 receives an optical signal 53 generated when the fundamental frequency light 10 scans the micro-hole 50. The optical signal 53 is a frequency multiplier signal of the fundamental frequency light. The photodetector 30 also converts the optical signal 53 into an electrical signal and amplifies it. A photomultiplier tube (PMT) is used in combination with the photodetector 30. A photomultiplier tube can convert a weak optical signal into a measurable current and amplify it significantly. Based on this, in the present invention, it is also possible to use other devices that can convert an optical signal into an electrical signal and amplify it instead of the photomultiplier tube, including but not limited to photodiodes (PDs), avalanche photodiodes (APDs), and charge-coupled devices (CCDs).

[0034] The signal processing and image module 40 is coupled to the photodetector 30, and acquires and processes the electrical signal from the photodetector 30, and also generates a micropore geometric structure image 60.

[0035] As shown in Figures 2 to 4, the micropore geometric structure image 60 includes, but is not limited to, cross-sectional and longitudinal section images, and may also be a two-dimensional or three-dimensional image. The characteristic of the micropore geometric structure image 60 is that it generates a strong interface enhancement frequency multiplication signal at the interface where the micropore 50 is in contact with other materials. That is, it has a high-intensity and clear interface enhancement frequency multiplication signal along the pore shape of the micropore 50, giving the micropore geometric structure image 60 high visualization resolution, which allows for direct observation of the shape and appearance of the micropore 50, or judgment of its quality, and also allows for analysis of the frequency multiplication signal. This enables high-precision measurement for pore size, shape, surface roughness, defects, cracks, etc., and can be applied to manufacturing process control and quality control of high aspect ratio micropores 50.

[0036] Based on the above, the high aspect ratio micro-hole inspection method of the optical frequency multiplication technology of the present invention includes the following procedure.

[0037] The system provides fundamental frequency light of a specific wavelength, which has sufficient energy to excite the interface between the micropores of the sample being measured and other materials (including, but not limited to, air), generating a frequency-multiplied signal.

[0038] The above-mentioned light beam scanning procedure is performed along the axis direction of the micropore in the sample to be measured, and this scanning procedure ensures that the fundamental frequency light can be scanned to the interface where the micropore and other materials come into contact.

[0039] The above frequency multiplication signal is captured, and a high-resolution micropore geometric structure image is generated. This micropore geometric structure image has a high-intensity and clear interface-enhanced frequency multiplication signal at the interface where the micropores and other materials meet, clearly showing the characteristics and defects of the micropore structure. [Explanation of Symbols]

[0040] 10 fundamental frequency light 20 Galvanometer Scanner System 21 Beam Expander 22 Attenuator 23 First Lens 24 Galvano Mirror 25 Second lens 30 Photodetectors 40 Signal Processing and Image Modules 50 micropores 51 Samples to be measured 53 Optical signals 60 Micropore geometry image

Claims

1. A high aspect ratio micro-hole inspection system using optical frequency multiplication technology, The system performs X-axis and Y-axis scanning on the sample to be measured, and also enters and scans the inside of the micropores of the sample along the Z-axis using fundamental frequency light, A photodetector is used to receive an optical signal generated when the fundamental frequency light scans the microhole, and to convert the optical signal into an electrical signal, wherein the optical signal is a frequency multiplier signal of the fundamental frequency light. A signal processing and image module is coupled to the aforementioned photodetector and is used to acquire and process the electrical signal and generate an image relating to the micropore geometric structure, wherein the micropore geometric structure image has a high-intensity and clear interface enhancement frequency multiplication signal at the interface where the micropores and other materials are in contact. A high-aspect-ratio micro-hole inspection system that includes optical frequency multiplication technology.

2. The high aspect ratio micropore inspection system using optical frequency multiplication technology according to claim 1, wherein the micropore geometric structure image includes a cross-sectional view, a longitudinal section, a two-dimensional image, and a three-dimensional image of the micropore.

3. The wavelength of the fundamental frequency light is 1200 to 1800 nm, wherein this is a high aspect ratio micropore inspection system using optical frequency multiplication technology according to claim 1.

4. The high aspect ratio micro-hole inspection system of optical frequency multiplication technology according to claim 3, wherein the fundamental frequency light is an infrared laser with a wavelength of 1560 nm.

5. Furthermore, the high aspect ratio micro-hole inspection system of optical frequency multiplication technology according to claim 1 includes a galvanometer scanner system used to adjust the single-point fundamental frequency light to a scanning fundamental frequency light.

6. The galvanoscanner system includes, but is not limited to, a combination of a beam expander, an attenuator, a first lens, a galvanoscanner mirror, and a second lens arranged along the direction of the fundamental frequency light, the high aspect ratio microhole inspection system of optical frequency multiplication technology according to claim 5.

7. The high aspect ratio micropore inspection system of optical frequency multiplication technology according to claim 1, wherein the photodetector is any one or a combination thereof of a photodiode (PD), an avalanche photodiode (APD), a charge-coupled device (CCD), a photomultiplier tube (PMT).

8. A high aspect ratio micro-hole inspection method using optical frequency multiplication technology, By scanning a fundamental frequency light of a specific wavelength along the axis of the micropore, the interface between the micropore and other materials is excited, generating an intense interface enhancement frequency multiplication signal, thereby acquiring a high-resolution and visualized image of the micropore geometric structure. A high aspect ratio micro-hole inspection method that includes optical frequency multiplication technology.

9. A high aspect ratio micro-hole inspection method using optical frequency multiplication technology, It provides fundamental frequency light of a specific wavelength, and this fundamental frequency light can excite the interface between the micropores of the sample to be measured and other materials, thereby generating a frequency-multiplied signal. A light beam scanning procedure is performed along the axis direction of the micropore in the sample to be measured, and the scanning procedure is performed so that the fundamental frequency light can scan up to the interface where the micropore and other materials come into contact. The frequency multiplication signal is captured, a high-resolution micropore geometric structure image is generated, and the micropore geometric structure image has a high-intensity and clear interface-enhanced frequency multiplication signal at the interface where the micropore and other materials are in contact, clearly showing the characteristics and defects of the micropore structure. A high-aspect-ratio micro-hole inspection method using optical frequency multiplication technology, which includes the following procedure.

10. The high aspect ratio micropore inspection method of optical frequency multiplication technology according to claim 9, wherein the wavelength of the fundamental frequency light is 1200 to 1800 nm.

11. The method for inspecting high aspect ratio micropores using optical frequency multiplication technology according to claim 10, wherein the wavelength is 1560 nm.

12. The high aspect ratio micropore inspection method of optical frequency multiplication technology according to claim 9, wherein the scanning procedure includes scanning along the X, Y, and Z axes of the sample to be measured, and the Z-axis scanning is a scan to a depth that penetrates the micropore.

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