Device and method for detecting surface defects of film sample on wafer

Abstract

The invention discloses a device and a method for detecting surface defects of a film sample on a wafer, and relates to the field of detection of the surface defects of the film sample on the wafer, and the device for detecting the surface defects of the film sample on the wafer comprises a line laser emitting device, a displacement module and a scattered light collecting module, the line laser emitting device is used for emitting line laser, a to-be-detected film sample is arranged on an emergent light path of the line laser emitting device, the to-be-detected film sample is arranged on the displacement module, and the displacement module is used for driving the to-be-detected film sample to move, so that the line laser irradiates any position on the surface of the to-be-detected film sample; the scattered light collection module is arranged on a scattered light path of the to-be-detected film sample and is used for acquiring an optical signal scattered by the to-be-detected film sample and processing the optical signal to obtain defect types, defect positions and defect sizes on the surface of the to-be-detected film sample; according to the invention, the efficiency of detecting various defects on the surface of the film sample on the wafer can be improved.

Description

Technical Field

[0001] This application relates to the field of surface defect detection of thin film samples on wafers, and in particular to a device and method for surface defect detection of thin film samples on wafers. Background Technology

[0002] During wafer manufacturing, a film is deposited on the wafer surface, making the detection of various defects on the thin film surface crucial. Thin film surface defects mainly include surface contamination, scratches, pinholes, bumps, and depressions. These defects can affect subsequent processes to varying degrees: surface contamination defects can block light during photolithography, leading to incomplete photolithographic patterns; scratches and pinholes can affect the integrity and electrical properties of the thin film; bumps and depressions can cause flatness issues in subsequent processes. Detecting the location, size, type, and number of various defects on the thin film surface of the wafer helps to identify factors that introduce defects and improve yield.

[0003] Current methods for detecting surface defects on wafer thin-film samples primarily employ optical scattering. These methods typically use 405nm or 488nm wavelength lasers to illuminate the thin-film surface. When the laser spot strikes a defect on the sample surface, scattering occurs. Different types of defects produce different scattering characteristics. Defect detection and classification are achieved by collecting the scattered light within a specified angular range using detectors at one or more angular positions. A spiral scanning method is usually used to traverse the thin-film sample surface. When a defect is detected, the polar coordinates of the laser spot's position are recorded, enabling the localization of the defect on the on-chip thin-film sample surface. The detection laser spot is usually an elliptical spot of 100×50μm or smaller, while wafer dimensions are typically between 100-300mm. This results in slow traversal speed and low efficiency. With the increasing development of the integrated circuit industry, higher demands are being placed on the efficiency of wafer surface defect detection in factories.

[0004] Therefore, there is an urgent need for a device that can improve the detection efficiency of various defects on the surface of thin film samples on wafers, in order to overcome the shortcomings of the above methods. Summary of the Invention

[0005] The purpose of this application is to provide a device and method for detecting surface defects of thin film samples on wafers, which can improve the efficiency of detecting various defects on the surface of thin film samples on wafers.

[0006] To achieve the above objectives, this application provides the following solution: Firstly, this application provides a surface defect detection device for thin film samples on a wafer, comprising: a line laser emitting device, a displacement module, and a scattered light collection module; the line laser emitting device is used to emit a line laser, the thin film sample to be detected is placed in the output light path of the line laser emitting device, the thin film sample to be detected is placed on the displacement module, the displacement module is used to move the thin film sample to be detected so that the line laser irradiates any position on the surface of the thin film sample to be detected; the scattered light collection module is placed in the scattered light path of the thin film sample to be detected, the scattered light collection module is used to acquire the light signal scattered by the thin film sample to be detected, and process the light signal to obtain the defect type, defect location, and defect size on the surface of the thin film sample to be detected.

[0007] In one embodiment, the line laser emitting device specifically includes: a laser and a beam shaping module; the beam shaping module is disposed in the output optical path of the laser, and the thin film sample to be tested is disposed in the output optical path of the beam shaping module; the beam shaping module is used to convert the laser emitted by the laser into a line laser.

[0008] In one embodiment, the wafer-on-wafer thin film sample surface defect detection device further includes: a vacuum adsorption platform; the vacuum adsorption platform is used to fix the thin film sample to be tested on the displacement module.

[0009] In one embodiment, the displacement module is a linear displacement stage.

[0010] In one embodiment, the scattered light collection module includes a scattered light collection lens group, a linear CCD array, and an acquisition module. The scattered light collection lens group is disposed in the scattered light path of the thin film sample to be tested, and the linear CCD array is disposed in the outgoing light path of the scattered light collection lens group. The linear CCD array is used to acquire the light signal output by the scattered light collection lens group and send the light signal to the acquisition module. The acquisition module is used to process the light signal to obtain the defect type, defect location, and defect size on the surface of the thin film sample to be tested.

[0011] In one embodiment, the beam shaping module includes a polarizer and a first cylindrical lens; the polarizer is disposed in the output light path of the laser, the first cylindrical lens is disposed in the output light path of the polarizer, and the thin film sample to be tested is disposed in the output light path of the first cylindrical lens.

[0012] In one embodiment, the scattered light collecting lens group includes a second cylindrical lens and a third cylindrical lens; the second cylindrical lens is disposed in the scattered light path of the thin film sample to be tested, the third cylindrical lens is disposed in the outgoing light path of the second cylindrical lens, and the linear CCD is disposed in the outgoing light path of the third cylindrical lens.

[0013] In one embodiment, the acquisition module includes: an acquisition module for acquiring the optical signal transmitted by the linear CCD.

[0014] The defect detection module is used to acquire the peak characteristics of the optical signal and obtain the type, location and size of defects on the surface of the thin film sample to be tested based on the peak characteristics.

[0015] Secondly, this application provides a method for detecting surface defects of thin film samples on wafers, which is applied to the aforementioned device for detecting surface defects of thin film samples on wafers. The method for detecting surface defects of thin film samples on wafers includes: acquiring the light signal scattered by the thin film sample after a line laser is irradiated onto the surface of the thin film sample to be tested.

[0016] The optical signal is processed to obtain the type, location, and size of defects on the surface of the thin film sample to be tested.

[0017] In one embodiment, the optical signal is processed to obtain the type, location, and size of defects on the surface of the thin film sample to be tested. Specifically, this includes: extracting the peak features of the optical signal and obtaining the type, location, and size of defects on the surface of the thin film sample to be tested based on the peak features.

[0018] According to the specific embodiments provided in this application, this application has the following technical effects: This application provides a device and method for detecting surface defects of thin film samples on wafers. By using line laser to irradiate the surface of thin film samples on wafers, the detection area is increased, the speed of detecting surface defects of thin film samples is improved, and rapid detection of various defects on the surface of thin film samples on wafers can be achieved. Attached Figure Description

[0019] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0020] Figure 1 This is a structural diagram of the wafer-on-thin-film sample surface defect detection device of this application.

[0021] Figure 2 This is a schematic diagram of the laser and beam shaping module of this application.

[0022] Figure 3 This is a schematic diagram of the structure of the scattered light collection module of this application.

[0023] Figure 4 This is a schematic diagram of the light spot and its movement on the surface of the thin film sample of this application.

[0024] Figure reference numerals: 1. Laser; 2. Polarizer; 3. First cylindrical lens; 4. Thin film sample to be tested; 5. Scattered light collecting lens group; 6. Linear CCD array; 7. Acquisition module; 8. Vacuum adsorption platform; 9. Linear displacement platform; 10. Defect; 11. Light spot. Detailed Implementation

[0025] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0026] To make the above-mentioned objectives, features and advantages of this application more apparent and understandable, the application will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0027] This application provides a device for detecting surface defects in thin film samples on wafers. In one exemplary embodiment, such as... Figure 1 As shown, the wafer-on-film sample surface defect detection device includes: a line laser emitting device, a displacement module, and a scattered light collection module; the line laser emitting device is used to emit a line laser, the film sample 4 to be detected is placed in the output light path of the line laser emitting device, the film sample 4 to be detected is placed on the displacement module, the displacement module is used to move the film sample 4 to be detected so that the line laser irradiates any position on the surface of the film sample 4 to be detected, thereby realizing defect detection at different positions on the sample surface; the scattered light collection module is placed in the scattered light path of the film sample 4 to be detected, the scattered light collection module is used to acquire the light signal scattered by the film sample 4 to be detected, and process the light signal to obtain the defect type, defect location, and defect size on the surface of the film sample 4 to be detected.

[0028] In another exemplary embodiment of this application, the line laser emitting device specifically includes: a laser 1 and a beam shaping module; the beam shaping module is disposed in the output optical path of the laser 1, and the thin film sample 4 to be tested is disposed in the output optical path of the beam shaping module; the beam shaping module is used to convert the laser emitted by the laser 1 into a line laser. The laser 1 is used to emit a 405nm wavelength laser as a light source.

[0029] In another exemplary embodiment of this application, the wafer-on-wafer thin film sample surface defect detection device further includes: a vacuum adsorption platform 8; the vacuum adsorption platform 8 is installed above the displacement module, and the vacuum adsorption platform 8 is used to fix the thin film sample 4 to be tested on the displacement module.

[0030] In another exemplary embodiment of this application, the displacement module is a linear displacement stage.

[0031] In another exemplary embodiment of this application, the scattered light collection module includes a scattered light collection lens group 5, a linear CCD 6, and a collection module 7.

[0032] The scattered light collecting lens group 5 is set in the scattered light path of the thin film sample 4 to be tested, and the linear CCD 6 is set in the output light path of the scattered light collecting lens group 5. The linear CCD 6 is used to acquire the light signal output by the scattered light collecting lens group 5 and send the light signal to the acquisition module 7. The acquisition module 7 is used to process the light signal to obtain the type, location and size of defects on the surface of the thin film sample 4 to be tested.

[0033] In another exemplary embodiment of this application, the beam shaping module includes: a polarizer 2 and a first cylindrical lens 3; the polarizer 2 is disposed in the output light path of the laser 1, the first cylindrical lens 3 is disposed in the output light path of the polarizer 2, and the thin film sample 4 to be tested is disposed in the output light path of the first cylindrical lens 3. The polarizer 2 is used to change the polarization direction of the incident light source to obtain P-polarized light or S-polarized light; the first cylindrical lens 3 is used to shape the obtained P-polarized light or S-polarized light to obtain a line laser.

[0034] In another exemplary embodiment of this application, the scattered light collecting lens group 5 includes a second cylindrical lens and a third cylindrical lens; the second cylindrical lens is disposed in the scattered light path of the thin film sample 4 to be tested, the third cylindrical lens is disposed in the outgoing light path of the second cylindrical lens, and the linear CCD 6 is disposed in the outgoing light path of the third cylindrical lens. The second cylindrical lens and the third cylindrical lens are used to collect scattered light within a specified scattering angle range. The scattered light generated by the surface defect 10 is collimated and converged by the second cylindrical lens and the third cylindrical lens in sequence; the linear CCD 6 is used to detect the light signal of the converged scattered light; the acquisition module 7 is used to acquire the signal value output by the linear CCD 6, and obtains the location, type, and size information of various defects on the surface of the thin film sample after data processing and feature analysis.

[0035] In another exemplary embodiment of this application, the acquisition module 7 includes: an acquisition module for acquiring the optical signal transmitted by the linear CCD 6.

[0036] The defect detection module is used to acquire the peak characteristics of the optical signal and obtain the type, location and size of defects on the surface of the thin film sample 4 to be tested based on the peak characteristics.

[0037] The operation steps for detecting surface defects of thin film samples on wafers using the above-mentioned device are as follows: First, place the thin film sample on the vacuum adsorption platform 8.

[0038] The second step is to turn on laser 1 for preheating. After laser 1 stabilizes, wait for the surface of the thin film sample to be traversed. After data processing, obtain the surface defect information of the thin film sample.

[0039] The working process of the wafer-on-thin-film sample surface defect detection device provided in this application is as follows: Figure 1 and Figure 2 As shown, laser 1 is tilted to irradiate the surface of the thin film sample. Polarizer 2 is placed behind laser 1 along the optical path to adjust the polarization state of the incident light. First cylindrical lens 3 is placed behind polarizer 2 to shape the obtained polarized light into linear laser irradiation onto the thin film sample 4 to be tested. The thin film sample 4 to be tested is fixed by vacuum adsorption platform 8, which is installed above linear displacement platform 9 to achieve traversal of the sample surface.

[0040] like Figure 1 and Figure 3 As shown, the scattered light collecting lens group 5 includes two cylindrical lenses. When the light spot 11 illuminates the defect 10, it generates scattered light. The scattered light collecting lens group 5 collects the scattered light within a specified angle range. The linear CCD 6 is placed behind the scattered light collecting lens group 5 to detect the intensity of the scattered light and to acquire the signal through the acquisition module 7.

[0041] like Figure 4 As shown, by moving the thin film sample 4 to be tested, the light spot 11 generated by the line laser can be scanned across the entire sample. Based on the peak size and number of the output signal from the linear CCD 6, the size, type, and number of different types of defects can be detected. Since the intensity distribution of the line laser spot is Gaussian, if a defect exists during the movement of the light spot 11, the intensity detected by the linear CCD 6 will change accordingly: surface contamination defects will produce symmetrical peaks that change from weak to strong and then back to weak; scratch defects will produce continuous signal changes; pinhole defects will produce negative signals; and protrusions and depressions will produce peaks of different amplitudes and shapes. By using existing technology to analyze the peak size, waveform characteristics, and duration of these scattered signals, defect classification can be achieved, and the precise location of the defect on the surface of the thin film sample can be detected based on the peak position.

[0042] 1. This application increases the detection area and improves the speed of detecting defects and contamination on the surface of thin film samples by using line laser irradiation on the surface of the wafer.

[0043] 2. By using a line laser, this application avoids the repeated defect counting caused by partial area overlap during the traversal of traditional elliptical or circular light spots, thereby improving the accuracy of on-chip thin film defect detection.

[0044] 3. This application simplifies the displacement structure of traditional methods by using only a linear displacement stage, thus avoiding defects and contamination positioning errors caused by the misalignment of the wafer thin film sample with the rotary stage in the traditional method.

[0045] This application also provides a method for detecting surface defects of thin film samples on wafers, which is applied to the aforementioned device for detecting surface defects of thin film samples on wafers. The method for detecting surface defects of thin film samples on wafers includes: acquiring the light signal scattered by the thin film sample after a line laser is irradiated onto the surface of the thin film sample to be tested.

[0046] The optical signal is processed to obtain the type, location, and size of defects on the surface of the thin film sample to be tested.

[0047] In an exemplary embodiment, processing the optical signal to obtain the defect type, defect location, and defect size on the surface of the thin film sample to be tested specifically includes: extracting the peak features of the optical signal, and obtaining the defect type, defect location, and defect size on the surface of the thin film sample to be tested based on the peak features.

[0048] The technical features of the above embodiments can be combined in any way. For the sake of brevity, 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.

[0049] This document uses specific examples to illustrate the principles and implementation methods of this application. The descriptions of the above embodiments are only for the purpose of helping to understand the methods and core ideas of this application. Furthermore, those skilled in the art will recognize that, based on the ideas of this application, there will be changes in the specific implementation methods and application scope. Therefore, the content of this specification should not be construed as a limitation of this application.

Claims

1. A wafer on film sample surface defect detection apparatus, characterized by, The wafer-on-film sample surface defect detection device comprises: The line laser emission device, the displacement module and the scattered light collection module; the line laser emission device is used for emitting line laser; the film sample to be detected is arranged on the outgoing light path of the line laser emission device; the film sample to be detected is arranged on the displacement module; the displacement module is used for driving the film sample to be detected to move, so that the line laser irradiates any position on the surface of the film sample to be detected; the scattered light collection module is arranged on the scattered light path of the film sample to be detected; the scattered light collection module is used for acquiring the light signal scattered by the film sample to be detected, and processing the light signal to obtain the defect type, defect position and defect size on the surface of the film sample to be detected.

2. The wafer on film sample surface defect inspection apparatus of claim 1, wherein The line laser emission device specifically comprises: The laser and the beam shaping module; the beam shaping module is arranged on the outgoing light path of the laser; the film sample to be detected is arranged on the outgoing light path of the beam shaping module; the beam shaping module is used for converting the laser emitted by the laser into line laser.

3. The wafer on film sample surface defect inspection apparatus of claim 1, wherein, The wafer-on-film sample surface defect detection device further comprises: a vacuum adsorption platform; the vacuum adsorption platform is used for fixing the film sample to be detected on the displacement module.

4. The wafer on film sample surface defect inspection apparatus of claim 1, wherein The displacement module is a linear displacement table.

5. The wafer on film sample surface defect inspection apparatus of claim 1, wherein, The scattered light collection module comprises a scattered light collection lens group, a line array CCD and an acquisition module; The scattered light collection lens group is arranged on the scattered light path of the film sample to be detected; the line array CCD is arranged on the outgoing light path of the scattered light collection lens group; the line array CCD is used for acquiring the light signal output by the scattered light collection lens group and sending the light signal to the acquisition module; the acquisition module is used for processing the light signal to obtain the defect type, defect position and defect size on the surface of the film sample to be detected.

6. The wafer on film sample surface defect inspection apparatus of claim 2, wherein The beam shaping module comprises: a polarizer and a first cylindrical lens; the polarizer is arranged on the outgoing light path of the laser; the first cylindrical lens is arranged on the outgoing light path of the polarizer; the film sample to be detected is arranged on the outgoing light path of the first cylindrical lens.

7. The wafer on film sample surface defect inspection apparatus of claim 5, wherein The scattered light collection lens group comprises: a second cylindrical lens and a third cylindrical lens; the second cylindrical lens is arranged on the scattered light path of the film sample to be detected; the third cylindrical lens is arranged on the outgoing light path of the second cylindrical lens; the line array CCD is arranged on the outgoing light path of the third cylindrical lens.

8. The wafer on film sample surface defect inspection apparatus of claim 5, wherein, The acquisition module comprises: An acquisition module is used for acquiring the light signal sent by the line array CCD; A defect detection module is used for acquiring the peak value characteristics of the light signal, and obtaining the defect type, defect position and defect size on the surface of the film sample to be detected according to the peak value characteristics.

9. A method for detecting surface defects in thin film samples on a wafer, characterized in that, The wafer-on-film sample surface defect detection device, the wafer-on-film sample surface defect detection method comprises: After the line laser irradiates the surface of the film sample to be detected, the light signal scattered by the film sample to be detected is acquired; The light signal is processed to obtain the defect type, defect position and defect size on the surface of the film sample to be detected.

10. The wafer on film sample surface defect inspection method of claim 9, wherein, The light signal is processed to obtain the defect type, defect position and defect size on the surface of the film sample to be detected, specifically comprising: The peak value characteristics of the extracted light signals are obtained, and the defect type, defect position and defect size on the surface of the film sample to be detected are obtained according to the peak value characteristics.

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