Wafer detection device and method for hyperspectral measurement and 3D measurement

Abstract

The invention discloses a wafer detection device and method for hyperspectral measurement and 3D measurement, and the device comprises a moving platform deck which is used for bearing a to-be-detected sample; the light source module, the first slit and the tube lens are sequentially arranged along the first light path; the tube lens comprises a light splitting module installed in the tube lens and an objective lens module installed on the side, away from the light source module, of the tube lens, the objective lens module comprises a first objective lens with axial dispersion and a second objective lens without axial dispersion, and the tube lens further comprises an objective lens switching module used for switching the first objective lens and the second objective lens; the tube lens, the second slit and the spectral imaging system are sequentially arranged along the second light path. Based on the characteristics of the infinite microscopic imaging system, the difference part of the 3D measurement module and the hyperspectral measurement module is used as a switching module, and other common parts are designed into a whole, so that the size is reduced, the system is simpler, the weight is lower, the detection efficiency is higher, and the cost is greatly saved.

Description

Technical Field

[0001] The present invention mainly relates to semiconductor wafer detection, and more specifically, to a wafer detection device and method for hyperspectral measurement and 3D measurement. Background Art

[0002] With the development of technology, semiconductor technology is increasingly widely used in daily life. Semiconductor production has different, complex, and numerous process stages / processes from beginning to end. Due to the complexity of the process and the large number of procedures, each stage requires strict quality inspection and assessment instruments and methods. For example, at the wafer stage, semiconductors need to be inspected for appearance defects or photoluminescence measurements. This intercepts defective products in the process stage to prevent them from continuing to flow into subsequent process stages and affecting the product yield. At the same time, discovering defects can also promote process improvement and optimization.

[0003] During the semiconductor wafer inspection stage, the inspection resolution is high, and a microscopic imaging device is required. However, the depth of field of such high-resolution microscopic imaging is generally very small, generally below 50μm. However, wafers generally have large fluctuations, and the XY platform at the bottom of the inspection platform cannot guarantee strict horizontal movement during operation. As a result, when shooting different areas, it is very likely that the wafer will exceed the depth of field, resulting in blurred imaging and inability to achieve accurate defect measurement.

[0004] In addition, the imaging detection solution that currently relies solely on camera imaging is no longer reliable. It is necessary not only to measure the defect characteristics of the surface product, but also to measure the luminous spectrum characteristics of the surface. Therefore, it is necessary to perform spectral measurement of the product during scanning.

[0005] In the existing technical solutions, 3D measurement module and spectral imaging measurement are usually completed by two machines and two sets of equipment due to the differences in their imaging systems. The equipment is large in size and interaction is difficult. Summary of the invention

[0006] In response to at least one defect or improvement need in the prior art, the present invention provides a wafer inspection device and method for hyperspectral measurement and 3D measurement. Based on the characteristics of an infinite microscopic imaging system, the different parts of a 3D measurement module and a hyperspectral measurement module are used as a switching module, and the other common parts are designed as a whole, thereby reducing the volume, making the system simpler, lighter, more efficient in detection, and greatly saving costs.

[0007] To achieve the above object, according to a first aspect of the present invention, a wafer inspection device for hyperspectral measurement and 3D measurement is provided, the device comprising: A mobile stage, used for carrying the sample to be tested; A light source module, a first slit, and a tube lens are sequentially arranged along a first optical path; the tube lens includes a spectroscopic module installed inside the tube lens and an objective lens module installed on a side away from the light source module, the objective lens module includes a first objective lens with axial dispersion and a second objective lens without axial dispersion, and also includes an objective lens switching module for switching the first objective lens and the second objective lens; and also includes a tube lens, a second slit, and a spectral imaging system sequentially arranged along a second optical path; the spectroscopic module is used to separate the first optical path and the second optical path; The light source module is used to emit polychromatic light, which follows the first optical path, passes through the first slit and the tube lens, is focused by the first objective lens, and is vertically irradiated on the surface of the sample to be tested; the first objective lens is also used to collect the polychromatic light reflected from the surface of the sample to be tested, which follows the second optical path, passes through the tube lens and the second slit, and enters the spectral imaging system to perform 3D measurement on the surface of the sample to be tested; After the surface height measurement of the sample to be tested is completed, the objective lens is switched to the second objective lens, and the spectral imaging system receives the imaging light of the sample to be tested transmitted along the second optical path, and performs hyperspectral measurement on the surface of the sample to be tested.

[0008] Furthermore, the wafer detection device for hyperspectral measurement and 3D measurement also includes: The first slit and the second slit are located at the image plane of the tube lens.

[0009] Furthermore, the wafer detection device for hyperspectral measurement and 3D measurement also includes: The spectral imaging system comprises a dispersion system, an imaging lens and an image acquisition system which are arranged in sequence.

[0010] Furthermore, the wafer detection device for hyperspectral measurement and 3D measurement also includes: The spectral imaging system further comprises a collimation system arranged at the front end of the dispersion system.

[0011] Furthermore, the wafer detection device for hyperspectral measurement and 3D measurement also includes: The dispersive system is a grating.

[0012] Furthermore, the wafer detection device for hyperspectral measurement and 3D measurement also includes: A control module, used for controlling the movable stage to move along a specified path, so that the spectral imaging system can perform 3D measurement on different locations of the surface of the sample to be measured, thereby achieving comprehensive 3D measurement of the surface of the sample to be measured; Alternatively, when the sample to be tested is relatively flat, the spectral imaging system can perform 3D measurement on the surface of the sample to be tested at a certain distance, thereby realizing sampling 3D measurement of the surface of the sample to be tested.

[0013] Furthermore, the wafer detection device for hyperspectral measurement and 3D measurement also includes: The imaging light on the surface of the sample to be tested comes from the self-luminescence of the sample to be tested or other illumination light.

[0014] Furthermore, the wafer detection device for hyperspectral measurement and 3D measurement also includes: The objective lens switching module is a nose wheel or a linear motor.

[0015] Furthermore, the wafer detection device for hyperspectral measurement and 3D measurement also includes: The magnification of the first objective lens and the second objective lens is selected according to the test requirements.

[0016] According to a second aspect of the present invention, a wafer detection method for hyperspectral measurement and 3D measurement is also provided, which is implemented by using a wafer detection device for hyperspectral measurement and 3D measurement as described in any one of the above items, including: The objective lens of the tube lens is switched to the first objective lens, and the light source system is turned on to generate polychromatic light to irradiate the surface of the sample to be tested through the first slit and the tube lens; The spectral imaging system receives the complex color light reflected by the surface of the sample to be measured, and performs 3D measurement on the surface of the sample to be measured; The objective lens of the tube lens is switched to a second objective lens, and the spectral imaging system receives imaging light from the surface of the sample to be measured, and performs hyperspectral measurement on the surface of the sample to be measured.

[0017] In general, the above technical solutions conceived by the present invention can achieve the following beneficial effects compared with the prior art: The present invention provides a wafer inspection device and method for hyperspectral measurement and 3D measurement. Based on the characteristics of an infinite microscopic imaging system, the different parts of a 3D measurement module and a hyperspectral measurement module are used as a switching module, and other common parts are designed as a whole, thereby reducing the volume, making the system simpler, lighter, more efficient in detection, and greatly saving costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0019] Figure 1 A schematic structural diagram of a wafer inspection device for hyperspectral measurement and 3D measurement provided by an embodiment of the present invention; Figure 2 A schematic diagram of the structure of a spectral imaging system provided in an embodiment of the present invention. DETAILED DESCRIPTION

[0020] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention. In addition, the technical features involved in the various embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0021] The terms "first", "second", "third", etc. in the specification and claims of the present invention and the above-mentioned drawings are used to distinguish different objects, rather than to describe a specific order. In addition, the terms "including" and "having" and any variations thereof are intended to cover non-exclusive inclusions. For example, a process, method, system, product or device that includes a series of steps or units is not limited to the listed steps or units, but optionally includes steps or units that are not listed, or optionally includes other steps or units inherent to these processes, methods, products or devices.

[0022] 3D detection of the wafer surface is a common detection content in wafer detection projects. The detection method is to obtain the height information of each point on the wafer surface. The spectral confocal method is a displacement measurement system. Its principle is that after the point complex light passes through the dispersion lens, the light beams of different wavelengths are focused onto planes of different depths. According to the principle of reversibility of the optical path, when the surface to be measured is located at a certain focal position, the focal spot of the corresponding wavelength passes through the dispersion lens, and the defocus of the surface to be measured can be determined by spectral analysis. For the spectral confocal method, please refer to the following prior art literature: Gao Xin, Deng Wenyi, Niu Chunhui. Research on displacement measurement system based on color confocal. Optical Technology, 38(1), 2012.

[0023] Based on the above principles, Figure 1 As shown, as the first embodiment of the present invention, a wafer detection device for hyperspectral measurement and 3D measurement is provided. The wafer detection device in this embodiment includes a first optical path and a second optical path. Among them, the first optical path, as a light path providing a 3D measurement light source, includes a light source module 1 and a tube lens 5. In this embodiment, the tube lens 5 is selected as the specific structural form of the optical path. The tube lens 5 includes an objective lens located on a side close to the sample 7 to be measured, and the objective lens structure includes at least a first objective lens 81 with axial dispersion. In this way, when the light source module 1 emits complex light (such as white light), the light of different wavelengths in the complex light can be focused on surfaces at different depths through the first objective lens 81 with axial dispersion. By receiving the reflected light from the surface of the sample 7 to be measured and performing spectral analysis, 3D measurement of the surface of the sample 7 to be measured can be achieved.

[0024] The dispersion of the first objective lens 81 is because the refractive index of white light (complex light) is different in the lens, causing it to focus at different places. Dispersion includes axial dispersion and off-axis dispersion. Dispersion needs to be eliminated or utilized according to different application scenarios. The first optical path in the present invention needs to utilize the axial dispersion characteristics of the first objective lens 81 to perform spectral confocal distance measurement. The size of the axial dispersion of the first objective lens 81 can be adjusted according to the size, structure, form, etc. of the device, and this is not limited in the present invention.

[0025] The wafer detection device in this embodiment also needs to perform hyperspectral measurement on the surface of the sample 7 to be tested. When performing hyperspectral measurement, the dispersion of the objective lens will cause the imaging quality to deteriorate, which is not conducive to hyperspectral measurement and analysis. Therefore, the objective lens structure of the present invention also needs to include at least one dispersion-free second objective lens 82. In this way, when the wafer detection device performs 3D measurement, the objective lens is switched to the first objective lens 81, and when performing hyperspectral measurement, the objective lens is switched to the second objective lens 82. There is no need to change other device structures. The same set of devices and optical paths can be used to achieve the two functions of 3D measurement and hyperspectral measurement. The switching method of the objective lens can be similar to the nose wheel of a microscope, or the objective lens switching can be controlled by a motor, or any other method that can be easily thought of by a person skilled in the art.

[0026] Furthermore, the magnification of the objective lens structure directly affects the effect of 3D measurement and hyperspectral measurement. Therefore, the magnification of the first objective lens 81 and the second objective lens 82 can be set according to the requirements. For example, for the specific structure of the first objective lens 81 and the second objective lens 82, simulation calculations can be performed based on dispersion requirements and magnification requirements by using common optical simulation software, such as zemax, codev, etc. Another implementation method is to set multiple first objective lenses 81 and / or multiple second objective lenses 82, and switch objective lenses with different magnifications according to requirements to achieve 3D measurement and hyperspectral measurement under multiple magnifications.

[0027] The second optical path in this embodiment is an imaging optical path for 3D measurement and hyperspectral detection, and the imaging device used is a spectral imaging system 2. For the spectral imaging system 2, Figure 2 As shown, its structure is a collimation system 21, a dispersion system 22, an imaging lens 23 and an image acquisition system 24 arranged in sequence. Light passes through the collimation system 21, the dispersion system 22 and the imaging lens 23 and reaches the image acquisition system 24. The image acquisition system 24 can be used as a spectrum analysis device in 3D measurement and as an imaging device in hyperspectral measurement.

[0028] In this embodiment, the first optical path and the second optical path share the tube lens 5. Therefore, a spectroscopic module 4 is provided in the tube lens 5. In this way, the first optical path and the second optical path can be partially coaxial, and the first optical path and the second optical path can be separated by the spectroscopic module 4, so that the light source module 1 and the spectral imaging system 2 do not affect each other.

[0029] Furthermore, slits are provided between the light source module 1 and the tube lens 5, and between the spectral imaging system 2 and the tube lens 5, respectively. Specifically, a first slit 31 is provided between the light source module 1 and the tube lens 5, and a second slit 32 is provided between the spectral imaging system 2 and the tube lens 5. Since this embodiment is a dispersion system, information on the entire surface in the object direction is obtained by scanning. The purpose of the slit is to ensure that at a specific scanning moment, only one line of light in the field of view in the scanning direction enters the optical system, and then the dispersion spectroscopic analysis is performed.

[0030] Furthermore, in order to achieve all-round coverage of the entire surface of the sample 7 to be tested, the mobile stage 6 for carrying the sample 7 to be tested is configured to be movable so as to perform a comprehensive scanning 3D measurement of the sample 7 to be tested. In this embodiment, two scanning modes can be selected according to the flatness of the surface of the sample 7 to be tested: when the surface of the sample 7 to be tested is not flat enough, the mobile stage 6 moves along a specified path, so that the spectral imaging system 2 can perform 3D measurement at different locations on the surface of the sample 7 to be tested, thereby achieving a comprehensive 3D measurement of the surface of the sample 7 to be tested; or when the sample 7 to be tested is relatively flat, the spectral imaging system 2 can perform 3D measurement at locations at a certain distance from the surface of the sample 7 to be tested, thereby achieving a sampling 3D measurement of the surface of the sample 7 to be tested.

[0031] Furthermore, the mobile stage 6 can also be configured to have six degrees of freedom, that is, the position can be arbitrarily adjusted in the xyz direction, and the position can be arbitrarily rotated around the xyz axis. In this way, when the tube lens 5 and the mobile stage 6 are not aligned, the posture of the mobile stage 6 can be arbitrarily adjusted to achieve alignment, thereby achieving more accurate 3D measurement and hyperspectral measurement.

[0032] Considering that the surface of the sample 7 to be measured may be uneven, a matching autofocus system can be provided, so that whenever the mobile stage 6 moves, the focus can be re-set to ensure the quality of 3D measurement and hyperspectral measurement. The autofocus system can use an inner coaxial autofocus system based on spectral confocality, and use the spectral imaging system 2 described in this embodiment to play the role of a spectrometer. Other autofocus systems can also be used, which will not be repeated here.

[0033] The technical features of the above embodiments may be combined arbitrarily. To make the description concise, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0034] It will be easily understood by those skilled in the art that the above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A wafer inspection device for hyperspectral measurement and 3D measurement, characterized in that: include: A movable carrier (6) for carrying a sample to be tested (7); A light source module (1), a first slit (31), and a tube lens (5) are sequentially arranged along a first light path; the tube lens (5) comprises a beam splitter module (4) installed therein and an objective lens module installed on a side thereof away from the light source module (1); the objective lens module comprises a first objective lens (81) having axial dispersion and a second objective lens (82) not having axial dispersion, and also comprises an objective lens switching module for switching the first objective lens (81) and the second objective lens (82); and further comprises a tube lens (5), a second slit (32), and a spectral imaging system (2) sequentially arranged along a second light path; the beam splitter module (4) is used to separate the first light path from the second light path; The light source module (1) is used to emit polychromatic light, which follows the first optical path, passes through the first slit (31) and the tube lens (5), is focused by the first objective lens (81), and is vertically irradiated onto the surface of the sample to be tested (7); the first objective lens (81) is also used to collect the polychromatic light reflected from the surface of the sample to be tested (7), follows the second optical path, passes through the tube lens (5) and the second slit (32), and enters the spectral imaging system (2), so as to perform 3D measurement on the surface of the sample to be tested (7); After the surface height measurement of the sample to be tested (7) is completed, the objective lens is switched to the second objective lens (82), and the spectral imaging system (2) receives the imaging light of the sample to be tested (7) transmitted along the second optical path, and performs hyperspectral measurement on the surface of the sample to be tested (7).

2. The wafer inspection device for hyperspectral measurement and 3D measurement according to claim 1, characterized in that: The first slit (31) and the second slit (32) are located at the image plane of the tube lens (5).

3. The wafer inspection device for hyperspectral measurement and 3D measurement according to claim 1, characterized in that: The spectral imaging system (2) comprises a dispersion system (22), an imaging lens (23) and an image acquisition system (24) which are arranged in sequence.

4. The wafer inspection device for hyperspectral measurement and 3D measurement as claimed in claim 3, characterized in that: The spectral imaging system (2) further comprises a collimation system (21) arranged at the front end of the dispersion system (22).

5. The wafer inspection device for hyperspectral measurement and 3D measurement as claimed in claim 3, characterized in that: The dispersive system (22) is a grating.

6. The wafer inspection device for hyperspectral measurement and 3D measurement according to claim 1, characterized in that: It also includes a control module for controlling the movable stage (6) to move along a specified path, so that the spectral imaging system (2) can perform 3D measurements on different locations on the surface of the sample to be tested (7), thereby achieving comprehensive 3D measurements on the surface of the sample to be tested (2); Alternatively, when the sample to be tested (7) is relatively flat, the spectral imaging system (2) can perform 3D measurement on the surface of the sample to be tested (7) at a certain distance, thereby realizing sampling 3D measurement of the surface of the sample to be tested (2).

7. The wafer inspection device for hyperspectral measurement and 3D measurement according to claim 1, characterized in that: The imaging light on the surface of the sample to be tested (7) originates from the self-luminescence of the sample to be tested (7) or other illumination light.

8. The wafer inspection device for hyperspectral measurement and 3D measurement as claimed in claim 1, characterized in that: The objective lens switching module is a nose wheel or a linear motor.

9. The wafer inspection device for hyperspectral measurement and 3D measurement according to claim 1, characterized in that: The magnifications of the first objective lens (81) and the second objective lens (82) are selected according to test requirements.

10. A wafer detection method for hyperspectral measurement and 3D measurement, characterized in that: The wafer detection device for hyperspectral measurement and 3D measurement as claimed in any one of claims 1 to 9 is implemented, comprising: The objective lens of the tube lens (5) is switched to the first objective lens (81), and the light source system (1) is turned on to generate polychromatic light which is irradiated onto the surface of the sample to be tested (7) through the first slit (31) and the tube lens (5); The spectral imaging system (2) receives the complex color light reflected by the surface of the sample to be tested (7), and performs 3D measurement on the surface of the sample to be tested (7); The objective lens of the tube lens (5) is switched to a second objective lens (82), and the spectral imaging system (2) receives imaging light from the surface of the sample to be measured (7), and performs hyperspectral measurement on the surface of the sample to be measured (7).

Images