Inspection equipment and inspection methods

Abstract

This system efficiently enables both effective global parameter testing and precise local parameter testing. [Solution] An inspection apparatus according to an embodiment of the present invention includes a light source assembly, an optical path system, an inspection system, and an optical path adjustment module. The optical path system is configured to guide the light source assembly to irradiate a wafer and generate an optical signal to be inspected. The inspection system includes a first tunnel and a second tunnel. The first tunnel receives the optical signal to be inspected and acquires a first optical signal at a first resolution of the wafer, and the second tunnel receives the optical signal to be inspected and acquires a second optical signal at a second resolution of the wafer. The optical path adjustment module is configured to adjust the transmission direction of the optical signal to be inspected so that the first and second tunnels receive the optical signal to be inspected. Here, the first resolution is greater than the second resolution.

Description

Technical Field

[0001] The present invention relates to the technical field of semiconductor inspection, and particularly to inspection equipment and inspection methods.

Background Art

[0002] With the development of science and technology and the expansion of market needs, in the semiconductor industry, higher requirements are placed on the production capacity and production efficiency of wafers. Large wafers can accommodate more transistors and circuit elements in one chip to achieve a high integration density of the chip, and can meet the market needs for multifunctionality and high performance.

[0003] While large wafers bring advantages, quality control and defect inspection in their production processes have become more complex and important. Currently, in the field of wafer defect inspection, mainly three methods of appearance inspection, electron beam inspection, and optical inspection are applied. Among them, optical inspection technology has great potential in the quality evaluation of the wafer surface, optical property analysis, and fine structure inspection due to features such as non-contact measurement, high-resolution imaging, and wide applicability, and has become a focus of attention in the industry.

[0004] However, for large wafers, the challenges of defect inspection are more severe, and there is a requirement to comprehensively monitor the performance parameters of the entire wafer and to be able to inspect local fine defects in real time and precisely. However, it is difficult for conventional inspection equipment to achieve both high inspection efficiency and local precision inspection.

Summary of the Invention

Problems to be Solved by the Invention

[0005] In view of this, one embodiment of the present invention provides inspection equipment and inspection methods, which can meet the requirements for comprehensive monitoring of the overall performance parameters of large wafers and local precision inspection, and efficiently achieve effective inspection of overall parameters and precise inspection of local parameters.

Means for Solving the Problems

[0006] According to one aspect, one embodiment of the present invention provides an inspection apparatus. The inspection apparatus includes a light source assembly, an optical path system, an inspection system, and an optical path adjustment module. The optical path system is configured to guide the light source assembly to irradiate a wafer and generate an optical signal to be inspected. The inspection system includes a first tunnel and a second tunnel. The first tunnel receives the optical signal to be inspected and obtains a first optical signal at a first resolution of the wafer, and the second tunnel receives the optical signal to be inspected and obtains a second optical signal at a second resolution of the wafer. The optical path adjustment module is configured to adjust the transmission direction of the optical signal to be inspected so that the first and second tunnels receive the optical signal to be inspected, where the first resolution is greater than the second resolution.

[0007] The addition of an optical path adjustment module enables wafer inspection at different resolutions within the same inspection facility, facilitating spatial multiplexing at different resolutions, improving the flexibility and versatility of wafer inspection, and facilitating rapid switching of inspection needs. Installing at least two inspection tunnels with different resolutions is advantageous for real-time and rapid acquisition of wafer performance parameters at different resolutions. Furthermore, since the same optical path system is shared, there is no need to install two independent optical path systems, contributing not only to reduced inspection costs and space savings but also to improved accuracy and consistency of inspection results from different inspection tunnels. Compared to inspection facilities with a single inspection tunnel, this improves the adaptability and functionality of the inspection facility and enhances inspection efficiency, while the addition of inspection tunnels does not excessively increase the complexity of the inspection facility or sacrifice inspection precision. Such a multi-tunnel design better meets the needs for comprehensive monitoring of overall performance parameters and localized precision inspection, providing more comprehensive and precise inspection results, and improving overall inspection performance and reliability.

[0008] In another aspect, one embodiment of the present invention provides an inspection method for inspecting a wafer. The inspection method includes the steps of: controlling an optical path system to generate an optical signal to be inspected for the wafer based on a control command; adjusting the position of an optical path adjustment module to cause a first sensor in a first tunnel in the inspection system to receive the optical signal to be inspected and acquire a first optical signal at a first resolution, and / or causing a second sensor in a second tunnel in the inspection system to receive the optical signal to be inspected and acquire a second optical signal at a second resolution; and processing the first optical signal and the second optical signal to acquire performance parameters of the wafer, wherein the first resolution is greater than the second resolution. [Brief explanation of the drawing]

[0009] The following drawings merely illustrate some embodiments of the present invention and do not limit its scope. In the drawings, identical or similar elements are indicated by the same or similar reference numerals. The drawings are schematic only, and the dimensions and proportions of the elements shown are not necessarily accurate. [Figure 1] This is a schematic diagram of the structure of an inspection equipment according to one embodiment of the present invention. [Figure 2] This is a schematic diagram of the structure of an inspection equipment according to one embodiment of the present invention. [Figure 3] This is a schematic diagram of the structure of the first tunnel and the second tunnel according to one embodiment of the present invention. [Figure 4] This is a schematic diagram of the structure of a first tunnel according to one embodiment of the present invention. [Figure 5] This is a schematic diagram of the structure of an inspection equipment according to one embodiment of the present invention. [Figure 6] This is a schematic diagram of the structure of an inspection equipment according to one embodiment of the present invention. [Figure 7] This is a schematic diagram of the structure of an inspection equipment according to one embodiment of the present invention. [Figure 8] This is a schematic diagram of the structure of a movable galvanoscanner according to one embodiment of the present invention. [Figure 9] This is a flowchart of an inspection method according to one embodiment of the present invention. [Figure 10] (a) to (d) are different scanning path diagrams for the entire wafer according to one embodiment of the present invention. [Figure 11] This is a schematic diagram of local scanning on a wafer according to one embodiment of the present invention. [Modes for carrying out the invention]

[0010] Hereinafter, embodiments of the present invention will be described illustratively with reference to the drawings. It should be noted that the embodiments of the present invention may vary, and should not be interpreted as being limited to the embodiments described herein. The embodiments described herein are merely for the purpose of providing a more thorough and clear understanding of the present invention.

[0011] In the manufacturing process of third-generation semiconductors, inspection of performance parameters such as wafer stress and deflection is crucial for both the wafer as a whole and localized areas, and significantly impacts quality control in subsequent manufacturing processes. Therefore, in the inspection of large wafers, comprehensive monitoring of overall performance parameters and precise inspection of local defects are complementary and inseparable.

[0012] The structure of a wafer inspection apparatus according to at least one embodiment of the present invention will be described in detail below with reference to the drawings. In the embodiments of the present invention, directional terms such as "up" and "down" are relative and not absolute. These directional terms are applicable when the wafer inspection apparatus or inspection method according to the embodiments of the present invention is arranged in the positions shown in the drawings.

[0013] Referring to Figure 1, one embodiment of the present disclosure provides an inspection system 100 applied to inspect a wafer 110, the inspection system 100 may include a light source assembly 120 and an optical path system 130.

[0014] The optical path system 130 guides the light source assembly 120 to illuminate the wafer 110 to generate the light signal 10 to be inspected. The light source assembly 120 may emit laser light of different wavelengths or white light. The optical path system 130 can be flexibly designed according to the requirements of the light signal to be inspected, and may include, for example, a combination of multiple lens groups or optical elements, or an optical assembly that generates interference. The light signal 10 to be inspected may be a transmitted light signal, a reflected light signal, an interfering light signal, or any light signal applicable to the inspection of wafer performance parameters. For example, by obtaining light signals to be inspected with different phase shift amounts (e.g., interfering light signals) using light sources of different wavelengths, and analyzing the light signals to be inspected, performance parameters such as wafer thickness, stress, and deflection can be obtained.

[0015] Continuing to refer to Figure 1, the inspection equipment 100 may further include an inspection system 140. The inspection system 140 may include a first tunnel 141 and a second tunnel 142, where the first tunnel 141 receives the optical signal to be inspected 10 and obtains a first optical signal 11 at a first resolution of the wafer 110, and the second tunnel 142 receives the optical signal to be inspected 10 and obtains a second optical signal 12 at a second resolution of the wafer 110. The first resolution is greater than the second resolution, so that different tunnels can receive wafer optical signals at different resolutions to meet the inspection needs of wafers at different resolutions.

[0016] Continuing to refer to Figure 1, the inspection equipment 100 may further include an optical path adjustment module 150 configured to adjust the transmission direction of the optical signal 10 to be inspected so that the first tunnel 141 and the second tunnel 142 receive the optical signal 10 to be inspected. In other words, after passing through the optical path system 130, the transmission direction of the optical signal 10 is adjusted by the optical path adjustment module 150, and then it is received by the first tunnel 141 and the second tunnel 142, thereby acquiring the optical signal of the wafer at different resolutions.

[0017] By adding an optical path adjustment module, it is possible to inspect wafers at different resolutions in the same inspection equipment, which is advantageous for realizing spatial multiplexing at different resolutions, improving the flexibility and diversity of wafer inspection, and facilitating the rapid switching of inspection needs. By installing at least two inspection tunnels with different resolutions, it is advantageous to obtain the performance parameters of the wafer at different resolutions in real time and quickly. In addition, by sharing the same optical path system, there is no need to install two independent optical path systems, which not only contributes to reducing inspection costs and saving space, but also contributes to improving the accuracy and consistency of inspection results from different inspection tunnels. Compared with the inspection equipment with a single inspection tunnel, it is advantageous to improve the adaptability and functionality of the inspection equipment and improve the inspection efficiency of the inspection equipment. On the other hand, increasing the number of inspection tunnels does not overly increase the complexity of the inspection equipment and does not sacrifice the precision of inspection. Such a multi-tunnel design can more effectively meet the needs of comprehensive monitoring of overall performance parameters and local precise inspection, is advantageous for providing more comprehensive and precise inspection results, and improves the overall inspection performance and reliability.

[0018] As long as the resolution of the first optical signal is greater than that of the second optical signal, the first optical signal and the second optical signal may be the optical signals to be inspected, or may be the optical signals to be inspected amplified at different magnifications. Correspondingly, for the first tunnel and the second tunnel, exemplarily, the first tunnel 141 may be a high-resolution tunnel applicable to precise measurement focusing on local fine structures, and the second tunnel 142 may be a low-resolution tunnel applicable to quickly grasping the performance of the entire wafer. Such a flexible switching mechanism greatly improves the inspection efficiency and reduces unnecessary repeated inspection steps. Needless to say, the inspection system may install a plurality of tunnels according to inspection requirements.

[0019] The optical path adjustment module 150 can be flexibly selected according to inspection requirements. For example, the optical signal to be inspected may be received in a time-division manner by the first tunnel and the second tunnel (see the first tunnel 141 and the second tunnel 142 in FIG. 1, or the first tunnel 541 and the second tunnel 542 in FIG. 5), or the optical signal to be inspected may be received simultaneously by the first tunnel and the second tunnel according to a certain ratio, direction or wavelength selection (see the first tunnel 241 and the second tunnel 242 in FIG. 2).

[0020] Referring to FIG. 1, the optical path adjustment module 150 may include a deflection mirror assembly. After the optical signal 10 to be inspected passes through the deflection mirror assembly, it is received by the first tunnel 141 or the second tunnel 142. For example, in the embodiment according to FIG. 5, the optical signal 10 to be inspected is received in a time-division manner by the first tunnel 541 and the second tunnel 542 after passing through the optical path system 530 and the deflection mirror assembly 550.

[0021] Note that by rotating or adjusting the position and angle of the deflection mirror assembly to guide the optical signal to be inspected to be received by the first tunnel or the second tunnel, the receiving tunnel can be flexibly switched. Due to advantages such as the mechanical stability, easy adjustment and small energy loss of the deflection mirror assembly, the introduction of the deflection mirror assembly is beneficial to improving the maintainability and reliability of the inspection equipment.

[0022] As an example, referring to FIG. 5, when the deflection mirror assembly 550 is located at the first position A1, the first tunnel 541 receives the amplified optical signal 10 to be inspected. When the deflection mirror assembly 550 is located at the second position A2, the second tunnel 542 receives the optical signal 54 to be inspected. This realizes the switching between different tunnels.

[0023] There are many implementation methods for controlling the switching of the position and angle of a deflection mirror assembly, such as mechanical, electrical, or algorithmic control. These implementation methods have advantages such as being easy to operate and easy to implement.

[0024] The first and second positions of the deflection mirror assembly may be designed according to different optical path systems, for example, by vertical movement as shown in Figure 5, or by other methods such as rotation, as long as the switching of the switching tunnel can be achieved. Furthermore, the relative positions of the first and second tunnels may be determined according to the design requirements of the optical path. For example, as shown in Figure 5, the first tunnel 541 and the second tunnel 542 may be installed vertically, and as shown in Figure 2, the first tunnel 241 and the second tunnel 242 may be installed parallel to each other. The positional relationship between the different tunnels is not specifically limited here.

[0025] Referring to Figure 3, the first tunnel 31 may include a first imaging assembly 313 and a first sensor 311. The first imaging assembly 313 is configured to amplify the optical signal 30 under inspection into a third optical signal 33, for example, the first sensor 311 may receive a local third optical signal 33 of the wafer 110 as the first optical signal. The second tunnel 32 may include a second imaging assembly and a second sensor 312, the second imaging assembly is configured to focus the optical signal 30 under inspection so that the second sensor 312 receives an optical signal at a second resolution, for example, a fourth optical signal 34 of the entire wafer 110 may be received as the second optical signal (i.e., total aperture measurement of the wafer). Referring to Figure 6, the first tunnel may further include a relay assembly 61, which is located in front of the first imaging assembly 62 and used to transmit optical signals, avoiding the occurrence of large losses and changes during transmission.

[0026] Furthermore, by adding a first imaging assembly to the first tunnel, it is not necessary to purchase separate, independent high-precision inspection equipment, making it easy and convenient to perform local high-resolution inspection of wafers, which is advantageous in reducing inspection costs. Adding a relay assembly is advantageous in ensuring that the optical signal to be inspected remains unchanged during the transmission process.

[0027] There are many ways to implement the relay assembly, such as a telecentric optical system and a double telecentric optical system, and we will not specifically limit ourselves to any of them here. As one example, referring to Figure 7, the relay assembly 71 may include an objective lens optical assembly 711 (closer to the deflection mirror assembly 750) and an eyepiece lens optical assembly 712 (farther from the deflection mirror assembly 750) arranged in order from the entrance pupil to the exit pupil, with the entrance pupil located at the front focal plane of the objective lens optical assembly and the exit pupil located at the back focal plane of the eyepiece lens optical assembly, and the back focal plane of the objective lens optical assembly and the front focal plane of the eyepiece lens optical assembly overlap. The objective lens optical assembly is configured to collect the incident beam, and the eyepiece lens optical assembly is configured to collimate the incident beam that has passed through the objective lens optical assembly. The refractive power φ_obj of the objective lens optical assembly and the refractive power φ_eye of the eyepiece lens optical assembly satisfy the following relationships: 0 < φ_obj < 0.006, 0 < φ_eye < 0.006, and 0.9 ≤ |φ_obj / φ_eye| ≤ 1.1. Designing in this way is advantageous in improving the entrance pupil distance and exit pupil distance, allows for more flexible addition of different sizes and numbers of optical elements before and after the optical relay assembly, reduces tolerance requirements for processing and adjustment, lowers the difficulty of the processing and mounting process, and further reduces the difficulty of controlling optical distortion.

[0028] The first imaging assembly can be implemented in many ways; for example, it may be a lens assembly, a telescope system, or another imaging assembly. The magnification of the first imaging assembly can be flexibly designed according to inspection requirements, for example, 2x, 5x, 10x, 20x, etc., thereby enabling high-resolution inspection of less than 10 μm by the first tunnel. The magnification of the first imaging assembly may also be a specific magnification or continuously adjustable. The magnification can be adjusted manually or automatically. The resolution of the first tunnel can be adjusted from 3 μm to 10 μm, and may be continuously adjusted or installed independently, for example, at 1 μm, 3 μm, 4 μm, 5 μm, 7 μm, and 10 μm. Of course, it can be installed at a resolution greater than 10 μm, for example, at 20 μm. The resolution of the second tunnel may be greater than 10 μm (a specific resolution may be set as needed), for example, at 45 μm, 60 μm, etc.

[0029] Referring to Figure 5, the first tunnel 541 may further include a drive unit configured to move the position of the first sensor 52 so that the third optical signal 53, amplified by the first imaging assembly 51, can be received by the first sensor 52, in cooperation with the first imaging assembly 51 and not limited by the receiving capability of the first sensor.

[0030] By installing a drive device, the first sensor can flexibly, accurately, and quickly acquire the third optical signal 53 at any local location on the wafer, thereby achieving more comprehensive and accurate collection of wafer optical signals.

[0031] There are many ways to implement a drive system; for example, it can be implemented by mechanical, electronic, or algorithmic control, and we will not specifically limit ourselves to any particular method here.

[0032] To further improve the accuracy and flexibility of reception by the first sensor, the first tunnel may further include a beam deflection assembly 441, as shown in Figures 4 and 6. The beam deflection assembly 441 is configured to enable scanning and positioning of the wafer 110 at any position, thereby allowing the third optical signal 45 amplified by the first imaging assembly 443 to be received by the first sensor 442 without moving the wafer.

[0033] Using Figure 6 as an example, the optical signal 10 to be inspected enters the first tunnel 641, passes through the relay assembly 61, is reflected by the beam deflection assembly 63, is then amplified into a third optical signal 10' by the first imaging assembly 62, and is received by the first sensor 66. And / or, the optical signal 10 to be inspected enters the second tunnel 642, is amplified or focused into a fourth optical signal 10″ by the second imaging assembly 64, and is then received by the second sensor 65.

[0034] By adjusting the position and angle of the beam deflection assembly, the first sensor can receive a high-resolution third optical signal at any position on the wafer without changing the wafer's position. This not only improves the accuracy of the first sensor but also simplifies the structure of the inspection equipment, making operation more convenient and controllable. This is advantageous for flexibly and efficiently acquiring optical signals at any position on the wafer, facilitating high-resolution inspection.

[0035] There are many methods for achieving precise control of the position and angle of the beam deflection assembly; for example, it may be an electromagnetic actuator, a piezoelectric actuator, or any other type, and is not specifically limited here.

[0036] Exemplary, a beam deflection assembly may be a beam scanning assembly. By rapidly and accurately moving the beam, it eliminates the need to move the wafer and the first sensor, contributing to scanning to different positions on the wafer, reducing errors during the movement process, and improving the accuracy and efficiency of the inspection equipment. There are many types of beam scanning assemblies, such as two mutually perpendicular one-dimensional galvanometer scanners, one two-dimensional galvanometer scanner, or a two-dimensional all-solid-state optical beam scanner, as long as the beam transmission direction can be changed; the type is not specifically limited here.

[0037] Referring to Figure 8, as an example, the beam deflection assembly 83 consists of a first galvanoscanner 831 and a second galvanoscanner 832 perpendicular to each other. The beam deflection assembly 83 can perform scanning and positioning at any position on the wafer 110, allowing the third optical signal 85 to be received by the first sensor 82.

[0038] To make it easier to understand, in this invention, each direction is indicated by an arrow, where arrow X+ points to one side of the first direction, arrow X- points to the other side of the first direction, arrow Y+ points to one side of the second direction, and arrow Y- points to the other side of the second direction.

[0039] Continuing to refer to Figure 8, the first galvanoscanner 831 may include a first support holder 8311 and a first reflecting mirror 8312, the first support holder 8311 being used to fix the first reflecting mirror 8312 and ensure its stability during operation. The first reflecting mirror 8312 moves along a first direction and is rotatable around the first direction by the drive of the first support holder 8311. The second galvanoscanner 832 may include a second support holder 8321 and a second reflecting mirror 8322, the second support holder 8321 being used to fix the second reflecting mirror 8322 and ensure its stability during operation. The second reflecting mirror 8322 moves along a second direction and is rotatable around the second direction by the drive of the second support holder 8321. The first support holder 8311 and the second support holder 8321 are installed vertically, and the first and second support holders 8311 and 8321 are driven by a control system to move the first and second reflective mirrors 8312 and 8322, thereby achieving positioning and scanning of the wafer to any position and any scanning mode. This implementation method has advantages such as high operability and ease of control.

[0040] Continuing to refer to Figure 2, the optical path adjustment module may also include a beam splitter assembly 250, and the optical signal 10 to be inspected is passed through the beam splitter assembly 250 and then split into the optical signal 21 and the optical signal 22 to be inspected, which are simultaneously received by the first tunnel 241 and the second tunnel 242.

[0041] Furthermore, by installing the beam splitter assembly 250 at the third position A3, the optical signal 10 to be inspected can be split into two or more independent optical signals, and typically the light is split according to a specific ratio, direction, or wavelength according to a specific rule and optical principle. The beam splitter assembly 250 may be, for example, a spectroscopic plate (realized by a spectroscopic film utilizing a spectroscopic surface), a power beam splitter, a prism beam splitter, or a half-mirror, as long as it can split the optical signal to be inspected into two or more independent optical signals.

[0042] By adding a beam splitter assembly, the inspection system achieves spatial and temporal multiplexing of the wafer and allows inspection of performance parameters on one side of the wafer at different resolutions, eliminating the need for two sets of inspection equipment. In this way, high-resolution optical signal acquisition for different locations on the wafer can be achieved within the same system, contributing to improved inspection efficiency for large wafers, reduced inspection costs, and maximum resource utilization.

[0043] The inspection equipment may further include a controller. The controller is configured to control the optical path system to generate an optical signal to be inspected for the wafer based on control commands, and to adjust the position of an optical path adjustment module so that a first sensor in a first tunnel in the inspection system receives the optical signal to be inspected and acquires a first optical signal at a first resolution, and / or so that a second sensor in a second tunnel in the inspection system receives the optical signal to be inspected and acquires a second optical signal at a second resolution. The controller is further configured to process the first and / or second optical signals to acquire performance parameters of the wafer. The controller may further be configured to modulate the wavelength of the laser in the light source assembly to acquire interference signals of different phase shift amounts. Based on the multiple interference optical signals of different phase shifts that have been collected, the shape parameters of the wafer are acquired by a specific algorithm.

[0044] The phase shift control system obtains interference signals with different phase shifts by modulating the wavelength of the laser in the light source assembly. Based on the collected interference optical signals with multiple different phase shifts, the wafer shape parameters are obtained using a specific algorithm. Of course, the phase shift system can also generate interference signals with different phase shifts by adjusting the distance between the standard mirror assembly and the wafer. In the interference signals generated by the phase shift control system, the phase shift amounts of two adjacent interference images are integer multiples of pi / 16 (a phase shift of 2pi corresponds to the movement period of one complete interference fringe).

[0045] Figure 9 shows an inspection method applied to wafer inspection according to one embodiment of the present invention.

[0046] In step S10, based on a control command, the optical path system is controlled to generate an optical signal to be inspected for the wafer, and the position of the optical path adjustment module is adjusted so that the optical signal to be inspected is received by a first sensor in the first tunnel of the inspection system to acquire a first optical signal at a first resolution, and / or the optical signal to be inspected is received by a second sensor in the second tunnel of the inspection system to acquire a second optical signal at a second resolution.

[0047] In step S11, if the optical path adjustment module is a deflection mirror assembly, the position of the optical path adjustment module is adjusted. This step includes controlling the deflection mirror assembly to be in a first position so that the first sensor can receive a first optical signal at a first resolution, and controlling the deflection mirror assembly to be in a second position so that the second sensor can receive a second optical signal at a second resolution.

[0048] The optical path adjustment module may be a beam splitter assembly, in which case the step of adjusting the position of the optical path adjustment module includes the step of controlling the beam splitter assembly to be in a third position and obtaining wafer performance parameters based on a first optical signal and a second optical signal.

[0049] In step S12, based on a control command, the beam deflection assembly is instructed to scan the wafer so that the first sensor receives a third optical signal at an arbitrary position on the wafer.

[0050] The beam deflection assembly is configured to adjust the transmission direction of the first optical signal to enable scanning at any position on the wafer. Preferably, the beam deflection assembly may include a beam scanning assembly, which may include, for example, two mutually perpendicular one-dimensional galvanometer scanners, one two-dimensional galvanometer scanner, and a two-dimensional all-solid-state optical beam scanner. The control command includes the scanning parameters and scanning mode of the beam deflection assembly.

[0051] As an example, let us specifically describe a beam deflection assembly consisting of two mutually perpendicular one-dimensional galvanoscanners. Referring to Figure 8, the control command instructs the first galvanoscanner 831 to move along a first direction and rotate around the first direction, and the second galvanoscanner 832 to move along a second direction and rotate around the second direction, so that the optical signal under inspection, after passing through the relay assembly, is reflected by the first galvanoscanner 831 and the second galvanoscanner 832, amplified into a third optical signal by the first imaging assembly, and then received by the first sensor (i.e., received as the first optical signal). In this case, the second sensor receives the second optical signal obtained through the second imaging assembly. The addition of the relay assembly is advantageous in ensuring that the optical signal entering the movable galvanoscanner matches the optical signal passing through the deflection mirror assembly as closely as possible.

[0052] In step S20, the first optical signal and the second optical signal are processed to obtain the wafer performance parameters.

[0053] The controller performs calculations and analyses based on the first and second optical signals to obtain parameter values ​​such as wafer thickness, stress, or deflection. For example, the first or second optical signal may be an interference signal, and performance parameters of the wafer at different resolutions are obtained by analyzing numerical values ​​such as the distance between fringes and the tilt angle in the interference signal. Of course, there are various technical methods for obtaining performance parameters, and these are not particularly limited here. In some examples, interference signals with different phase shift amounts (for example, the phase shift amounts of two adjacent interference images are integer multiples of pi / 16) are obtained by modulating light source assemblies of different wavelengths, and wafer shape parameters are obtained using a specific algorithm based on the multiple interference signals with different phase shifts that have been collected.

[0054] In the following section, referring to Figure 7, we will briefly explain the structure of the inspection equipment and the inspection process, using the example of an optical path system generating an interference optical signal.

[0055] The inspection equipment 700 may include a light source assembly 120, an optical path system 730, a deflection mirror assembly 750, and an inspection system 740.

[0056] The optical path system 730 may include a standard mirror assembly 74, a collimating and collecting assembly 75, a quarter-wave plate assembly 76, a polarizing beam splitter assembly 77, and an aperture assembly 78, which are configured to generate an interference optical signal and direct it onto the deflecting mirror assembly 750. Here, the distance between the reference standard mirror and the wafer is less than 50 mm, and of course, the smaller the distance between them, the better, but this must also be determined according to the design of the optical path.

[0057] The inspection system 740 may include a first tunnel 742, a second tunnel 741, and a phase shift control system. The first tunnel 742 may include a relay assembly 71, a movable galvanometer scanner 73, a first imaging assembly 72, and a first sensor 79. The second tunnel 742 may include a second imaging assembly 81 and a second sensor 80. When the deflection mirror assembly 750 is in the fourth position B1, the optical signal to be inspected is received by the first tunnel 742, and when the deflection mirror assembly 750 is in the fifth position B2, the interference optical signal is received by the second tunnel 741. Here, AA represents a cross-sectional view of the beam scanning assembly along the direction perpendicular to the plane of the paper in the actual optical path. Of course, the optical path system may have only one inspection tunnel and is not particularly limited here.

[0058] The inspection process for the entire wafer (the second tunnel, i.e., the low-resolution tunnel) is as follows:

[0059] After the control command for the overall inspection is input, the controller adjusts the distance between the wafer and the standard mirror to the standard distance (less than 50 mm) and adjusts the deflection mirror assembly 750 to be in the fifth position B2. Light from the light source assembly 120 is irradiated onto the wafer 110 via the polarizing beam splitter assembly 77 and reflected. The reflected light then passes sequentially through the collimating assembly 75, the quarter-wave plate assembly 76, the polarizing beam splitter assembly 77, and the aperture assembly 78, and together with the beam irradiated onto the standard mirror 74 and reflected, forms an interference optical signal (i.e., the light signal to be inspected). The interference optical signal passes through the deflection mirror assembly 750 and is received by the second sensor in the second tunnel through the second imaging assembly. The controller modulates different wavelengths to obtain interference optical signals with different phase shift amounts. By calculating and analyzing the interference optical signals with different phase shift amounts received by the second sensor, parameters such as the overall wafer thickness, deflection, and stress are obtained.

[0060] The inspection process for a specific area of ​​the wafer (the first tunnel, i.e., the high-resolution tunnel) is as follows:

[0061] A control command for local inspection is input, and the deflection mirror assembly 750 is adjusted to the fourth position B1. Interferential optical signals generated during the overall inspection process pass sequentially through the deflection mirror assembly 750, the relay assembly 71, and the movable galvanometer scanner 73. The position and angle of the movable galvanometer scanner scan the local area of ​​the wafer according to the controller's instructions, and the optical signal after scanning passes through the first imaging assembly 72 and can be received by the first sensor 79. This allows for the acquisition of high-resolution interferential optical signals at arbitrary positions on the wafer 110, and parameters such as local deflection and stress on the wafer are obtained through analysis calculations. By performing multiple consecutive scans, a high-resolution image of the entire wafer is obtained.

[0062] Of course, depending on the inspection requirements, a beam deflection assembly may be installed in the second tunnel. As one example, it may be necessary to perform different scanning modes on a 300mm x 300mm wafer depending on the inspection requirements. By inputting control commands for different scanning modes, the first and second galvanometer scanners can scan according to specific scanning parameters and scanning modes. Scanning parameters may include scanning speed, scanning range, scanning frequency, etc., and scanning modes may include scanning direction, scanning path, etc. The scanning path may be a Lissajou curve (see Figure 10(a)), a helical curve (see Figure 10(b)), a hexagon (see Figure 10(c)), a quadrilateral (see Figure 10(d)), etc. Of course, the scanning path may be edited as needed.

[0063] For example, a wafer measuring 300 mm x 300 mm may be scanned multiple times to obtain an overall image of the wafer. For high-resolution scanning, the number of scans is calculated according to the desired resolution. For instance, referring to Figure 11, the area scanned each time is 35 mm x 47 mm. At least 300 x 300 / (35 x 47) ≈ 55 scans are required to obtain a high-resolution optical signal of the entire wafer. If a 20% coverage rate (i.e., 20% of the edge area is shared) is desired, at least 300 x 300 / (35 x 47 x 80%) ≈ 70 scans are required to obtain a high-resolution overall image of the wafer.

[0064] In addition, equipment with different symbols in the above drawings can refer to equipment with the same function and can be adaptively adjusted according to actual needs in actual applications.

[0065] In addition, terms such as "first" or "second" are used to describe various elements (e.g., the first tunnel and the second tunnel) in embodiments of the present invention, but these elements are not defined by these terms; rather, these terms are used merely to distinguish one element from another.

[0066] The drawings are merely examples and do not limit the optical path diagram structure. The optical path schematics may be in a parallel relationship, a progressive relationship, or combined with each other. The optical path units in each optical path schematic may also be combined by referencing each other. To avoid unnecessary redundancy, the present invention will not separately describe the various possible combination methods.

[0067] In some embodiments relating to this application, the disclosed systems and elements may be implemented in other ways. For example, the embodiments of elements described above are merely illustrative. For example, the division of a unit or module is merely a division of logical function, and there may be other division patterns in actual implementation. For example, multiple units or modules may be combined or integrated into another system. Some features may be ignored or not implemented. Also, the shown or considered coupling, direct coupling or communication connection between elements may be an indirect coupling or communication connection via several interfaces, units or modules, and may be in an electrical or other form.

[0068] Furthermore, each functional unit or module in each embodiment of the present disclosure may be integrated into a single processing unit or module, each unit or module may exist physically independently, or two or more units or modules may be integrated into a single unit or module.

[0069] Although specific embodiments of the present invention have been described above, the scope of protection of the present invention is not limited thereto. Any modifications or substitutions that a person skilled in the art could conceive within the technical scope disclosed herein should all be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be in accordance with the claims.

Claims

1. Inspection equipment used to inspect wafers, Light source assembly and An optical path system configured to guide the light source assembly to illuminate the wafer and generate an optical signal to be inspected, An inspection system comprising a first tunnel and a second tunnel, wherein the first tunnel receives the optical signal to be inspected and acquires a first optical signal at a first resolution of the wafer, and the second tunnel receives the optical signal to be inspected and acquires a second optical signal at a second resolution of the wafer, The optical path adjustment module is configured to adjust the transmission direction of the optical signal to be inspected so that the first tunnel and the second tunnel receive the optical signal to be inspected. The first resolution is greater than the second resolution. Inspection equipment characterized by the following features.

2. The optical path adjustment module includes a deflection mirror assembly, and the optical signal to be inspected is received by the first tunnel and the second tunnel after passing through the deflection mirror assembly. The inspection equipment according to claim 1, characterized by the features described above.

3. When the deflection mirror assembly is in the first position, the first tunnel receives the light signal to be inspected, and when the deflection mirror assembly is in the second position, the second tunnel receives the light signal to be inspected. The inspection equipment according to claim 2, characterized by its features.

4. The first tunnel includes a first imaging assembly and a first sensor, the first imaging assembly is configured to amplify the optical signal to be inspected into a third optical signal, thereby causing the first sensor to receive the third optical signal from a local area of ​​the wafer as a first optical signal. The second tunnel includes a second sensor configured to receive a fourth optical signal from the entire wafer as the second optical signal. The inspection equipment according to claim 1, characterized by the features described above.

5. The first tunnel further includes a beam deflection assembly, The beam deflection assembly is configured to cause the first sensor to receive the third optical signal by scanning and positioning the wafer at an arbitrary position. The inspection equipment described in feature 4.

6. The beam deflection assembly includes a beam scanning assembly. The inspection equipment according to claim 5, characterized in that it is a feature of the present invention.

7. The beam scanning assembly includes a first galvanoscanner and a second galvanoscanner that are perpendicular to each other, and the first and second galvanoscanners are configured to cause the third optical signal to be received by the first sensor by scanning and positioning at an arbitrary position on the wafer. The inspection equipment according to claim 6, characterized by the features described above.

8. The optical path adjustment module includes a beam splitter assembly. The optical signal to be inspected passes through the beam splitter assembly and is then received by the first tunnel and the second tunnel to acquire the first optical signal at the first resolution and the second optical signal at the second resolution of the wafer. The inspection equipment according to claim 1, characterized by the features described above.

9. The optical signal to be inspected is an interfering optical signal. The inspection equipment according to claim 1, characterized by the features described above.

10. The aforementioned inspection equipment further includes a controller, The aforementioned controller, The system is configured to control the optical path system to generate an optical signal to be inspected for the wafer based on a control command, and to adjust the position of the optical path adjustment module so that the first sensor in the first tunnel of the inspection system receives the optical signal to be inspected and acquires a first optical signal at a first resolution, and / or so that the second sensor in the second tunnel of the inspection system receives the optical signal to be inspected and acquires a second optical signal at a second resolution. The controller is further configured to process the first optical signal and / or the second optical signal to obtain performance parameters of the wafer. The inspection equipment according to claim 1, characterized by the features described above.

11. A method for inspecting wafers. The steps include controlling the optical path system to generate an optical signal to be inspected for the wafer based on a control command, adjusting the position of the optical path adjustment module to cause a first sensor in a first tunnel in the inspection system to receive the optical signal to be inspected and acquire a first optical signal at a first resolution, and / or causing a second sensor in a second tunnel in the inspection system to receive the optical signal to be inspected and acquire a second optical signal at a second resolution, The step includes processing the first optical signal and the second optical signal to obtain performance parameters of the wafer, The first resolution is greater than the second resolution. A testing method characterized by the following features.

12. The optical path adjustment module is a deflection mirror assembly, The above step of adjusting the position of the optical path adjustment module is, The steps include controlling the deflection mirror assembly to be positioned in a first position so that the first sensor receives a first optical signal at a first resolution, The steps include controlling the deflection mirror assembly to be positioned in a second position so that the second sensor receives a second optical signal at a second resolution, The inspection method according to feature 11.

13. The aforementioned optical path adjustment module is a beam splitter assembly, The above step of adjusting the position of the optical path adjustment module is, The steps include controlling the beam splitter assembly to be positioned in a third position and obtaining performance parameters of the wafer based on the first and second optical signals, The inspection method according to feature 11.

14. The further step includes instructing the beam deflection assembly to scan the wafer based on the control command, thereby causing the first sensor to receive a third optical signal from an arbitrary position on the wafer as the first optical signal. The inspection method according to feature 12.

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