Wafer detection method

Abstract

A wafer detection method includes: loading a first wafer to an optical detection device; positioning the first wafer; detecting the first wafer and generating first wafer optical data; loading a second wafer to an optical detection device; positioning a second wafer; detecting a second wafer and generating second wafer optical data; comparing the first wafer optical data with the second wafer optical data; judging whether the first wafer optical data and the second wafer optical data are the same or not; obtaining a minimum unit pattern on the second wafer when it is determined that the second wafer optical data is substantially different from the first wafer optical data; detecting optical data of the first wafer unit and optical data of the second wafer unit according to the minimum unit pattern; and comparing the optical data of the first wafer unit with the optical data of the second wafer unit.

Description

Technical Field

[0001] The present invention relates to a detection method, and in particular to a wafer detection method. Background Art

[0002] The manufacture of semiconductor devices generally involves processing semiconductor wafers using a large number of processes to form various features and multiple levels of semiconductor devices. Defects may be formed during any process. Therefore, after more than one process step, the wafer needs to be inspected for defects.

[0003] Difference images have been used for defect detection. Usually, the difference images are obtained by comparing the target image with the reference image. However, some image differences are sometimes incorrectly marked as defects. Therefore, how to correctly judge the defect status of the wafer is one of the problems that need to be solved urgently. Summary of the invention

[0004] The present invention provides a wafer detection method which can correctly judge the defect state of the wafer.

[0005] The present invention provides a wafer detection method, which includes: loading a first wafer into an optical detection device; positioning the first wafer; detecting the first wafer and generating optical data of the first wafer; loading a second wafer into the optical detection device; positioning the second wafer; detecting the second wafer and generating optical data of the second wafer; comparing the optical data of the first wafer with the optical data of the second wafer; determining whether the optical data of the first wafer and the optical data of the second wafer are the same; when determining that the optical data of the second wafer is substantially different from the optical data of the first wafer, obtaining a minimum unit pattern on the second wafer; detecting the optical data of the first wafer unit and the optical data of the second wafer unit according to the minimum unit pattern; and comparing the optical data of the first wafer unit with the optical data of the second wafer unit.

[0006] In some embodiments, the wafer inspection method further includes: determining whether the optical data of the first wafer unit and the optical data of the second wafer unit are the same; and when it is determined that the optical data of the second wafer unit is substantially different from the optical data of the first wafer unit, determining that the second wafer is in a defective state.

[0007] In some embodiments, obtaining the minimum unit pattern on the second wafer includes: reading preset pattern data; obtaining at least two unit patterns according to the preset pattern data; and obtaining the minimum unit pattern according to the at least two unit patterns.

[0008] In some embodiments, detecting the optical data of the first chip unit and the optical data of the second chip unit includes: restoring the arrangement of at least two chip units of the preset pattern data according to the minimum unit figure; selecting the adjacent first chip unit and second chip unit among the at least two chip units; and detecting the optical data of the first chip unit and the optical data of the second chip unit.

[0009] In some embodiments, inspecting the first wafer and generating first wafer optical data includes: irradiating the upper surface of the first wafer with mixed light; receiving reflected light from the upper surface of the first wafer; and generating the first wafer optical data according to the reflected light.

[0010] In some embodiments, irradiating the upper surface of the first wafer with the mixed light includes: irradiating the upper surface of the first wafer with the mixed light at a preset incident angle. In some embodiments, the mixed light includes at least two light beams with different wavelengths.

[0011] In some embodiments, inspecting the first wafer and generating first wafer optical data includes: storing the first wafer optical data as reference data.

[0012] In some embodiments, the first wafer and the second wafer are loaded into the optical inspection device at the same time.

[0013] In some embodiments, detecting the second wafer and generating second wafer optical data includes: rotating the second wafer by a preset angle; irradiating the upper surface of the second wafer with mixed light; receiving reflected light from the upper surface of the second wafer; and generating second wafer optical data based on the reflected light.

[0014] As mentioned above, the wafer detection method of the present invention loads two wafers (for example, a first wafer and a second wafer) into an optical detection device and generates wafer optical data respectively. By comparing the wafer optical data of the two wafers, it can be determined whether there is a difference between the two. If it is determined that there is a difference after the detection, the optical data of each chip on one of the wafers can be compared. In other words, after the wafer detection method of the present invention has compared the wafer optical data of the first wafer (for example, as a reference wafer) and the second wafer (for example, as a test wafer), if there is a difference between the two, at least two chips on the test wafer can be further detected to determine whether the test wafer is really in a defective state. In this way, the wafer detection method of the present invention can first detect the wafer state on a large scale, and then detect the wafer details to remove the influence of slight optical property unevenness caused by the process, so as to improve the accuracy of wafer detection.

[0015] The above summary is for illustrative purposes only and is not intended to be limiting in any way. In addition to the illustrative aspects, embodiments and features described above, further aspects, embodiments and features of the present application will be readily apparent by reference to the accompanying drawings and the following detailed description. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] In the accompanying drawings, unless otherwise specified, the same reference numerals throughout the multiple drawings represent the same or similar parts or elements. These drawings are not necessarily drawn to scale. It should be understood that these drawings only depict some embodiments disclosed in the present application and should not be regarded as limiting the scope of the present application.

[0017] The details of one or more embodiments of the subject matter described in this specification are set forth in the following drawings and description. Other features, aspects, and advantages of the subject matter of this specification will become apparent from the description, drawings, and claims, including:

[0018] Figure 1 A diagram showing the steps of a wafer inspection method of the present invention.

[0019] FIG. 2A to FIG. 2E It is a schematic diagram showing the flow of the wafer detection method of the present invention.

[0020] FIG. 3A to FIG. 3E It is a schematic diagram showing the flow of the wafer detection method of the present invention.

[0021] FIG. 4A to FIG. 4D It is a schematic diagram showing the flow of the wafer detection method of the present invention.

[0022] Figure 5A and Figure 5B It is a schematic diagram showing the flow of the wafer detection method of the present invention.

[0023] Description of reference numerals:

[0024] 1, 3: wafer;

[0025] 11, 31: Wafer optical data;

[0026] 311: different parts;

[0027] 2: Optical detection device;

[0028] 4: minimum unit figure;

[0029] 5: Preset pattern data;

[0030] 51: unit graphics;

[0031] 52: vertical line;

[0032] 53: horizontal line;

[0033] 54, 61, 62: chip unit;

[0034] S01~S11: steps. DETAILED DESCRIPTION

[0035] As used herein, terms such as "first," "second," and the like describe various elements, components, regions, layers, and / or portions, which should not be limited by these terms. These terms may only be used to distinguish one element, component, region, layer, or portion from another. Unless the context clearly indicates otherwise, terms such as "first," "second," and the like as used herein do not imply a sequence or order.

[0036] Figure 1 The figure is a step diagram representing a wafer detection method of the present invention. The wafer detection method of the present invention includes steps S01 to S11. In step S01, a first wafer is loaded into an optical detection device. In step S02, the first wafer is positioned. In step S03, the first wafer is detected and the optical data of the first wafer is generated. In step S04, a second wafer is loaded into the optical detection device. In step S05, the second wafer is positioned. In step S06, the second wafer is detected and the optical data of the second wafer is generated. In step S07, the optical data of the first wafer and the optical data of the second wafer are compared. In step S08, it is determined whether the optical data of the first wafer and the optical data of the second wafer are the same. In step S09, when it is determined that the optical data of the second wafer is substantially different from the optical data of the first wafer, the minimum unit pattern on the second wafer is obtained. In step S10, the optical data of the first wafer unit and the optical data of the second wafer unit are detected according to the minimum unit pattern. In step S11 , the optical data of the first chip unit and the optical data of the second chip unit are compared.

[0037] FIG. 2A to FIG. 2E FIG. 2 is a schematic diagram showing the flow of the wafer detection method of the present invention. Figure 1 and Figure 2AAs shown, in step S01, a wafer (e.g., a first wafer) 1 is loaded into an optical detection device 2. Wafer 1 is, for example, a semiconductor wafer on which a patterned wafer film layer is formed. The optical detection device 2 may, for example, include a light source, a carrier, an optical imaging module, a storage module, a computing module and / or an interface module, etc., which are not restrictive. It is worth mentioning that the light source may, for example, be an external coaxial light source, an annular light source, an oblique light source or other light-emitting device that can be used for defect detection and is integrated with a light-emitting diode. In addition, the light source may also include at least two active light sources arranged in a one-dimensional or two-dimensional matrix to simultaneously output light to each part of the wafer 1. Furthermore, the optical imaging module is, for example, disposed above the carrier, and may have a semiconductor photosensitive element, such as a charge coupled device (CCD) lens, etc., to receive reflected light reflected from the wafer 1.

[0038] In some embodiments, the light source has, for example, light emitting diodes with different wavelengths to generate mixed light. For example, a mixed light generated by a red light emitting diode emitting red light with a wavelength of 620 nanometers (nm) to 750nm and a green light emitting diode emitting green light with a wavelength of 495nm to 570nm is not intended to limit the present invention, and mixed light with more than three wavelengths can also be used. Furthermore, the mixing ratio of light of different wavelengths in the mixed light is not restrictive, for example, 70% to 90% of red light and 10% to 30% of green light can be used to mix, which is not intended to limit the present invention.

[0039] In some embodiments, the incident angle of the light source to the upper surface of the wafer 1 (preset incident angle) and the offset angle of the optical imaging module relative to the normal of the upper surface of the wafer 1 can be set differently according to the design. For example, the light source and the optical imaging module can be perpendicular to the upper surface of the wafer 1, but located at different heights. That is, the incident angle of the light source relative to the normal of the upper surface of the wafer 1 is 0 degrees (that is, the two are parallel), and the offset angle of the optical imaging module relative to the normal of the upper surface of the wafer 1 is also 0 degrees. For another example, the incident angle of the light source relative to the normal of the upper surface of the wafer 1 can be offset by 5 degrees to 10 degrees, and the offset angle of the optical imaging module relative to the normal of the upper surface of the wafer 1 can be -5 degrees to -10 degrees, and the two are set corresponding to each other. It should be noted that the positive and negative angles indicate that the offset direction from the normal is different, for example, 5 degrees means a 5-degree offset to the right from the normal, and -5 degrees means a 5-degree offset to the left from the normal.

[0040] like Figure 1 , Figure 2B and Figure 2C As shown, in step S02, the wafer 1 is positioned. Figure 2BAs shown, the carrier of the optical detection device 2 can rotate, and the optical imaging module of the optical detection device 2 can automatically detect the positioning notch of the wafer 1 to perform positioning. In this embodiment, the optical imaging module of the optical detection device 2 automatically selects and detects the four corners of the wafer 1 as an example for explanation, but it is not intended to limit the present invention, and different positions can be selected and detected according to different designs. Figure 2C As shown, the optical imaging module of the optical inspection device 2 can also capture images of four corners of the wafer 1 to record alignment information, which is not intended to limit the present invention.

[0041] like Figure 1 , Figure 2D and Figure 2E As shown, in step S03, the wafer 1 is detected and wafer optical data 11 (for example, first wafer optical data) is generated. In some embodiments, the light source of the optical detection device 2 can use light of various wavelengths, angles and / or brightness to illuminate the upper surface of the wafer 1. For example, the light source of the optical detection device 2 can use the mixed light as described above, and illuminate the upper surface of the wafer 1 at the preset incident angle as described above. The optical imaging module of the optical detection device 2 can receive the reflected light from the upper surface of the wafer 1 to generate the wafer optical data 11. In other words, the optical imaging module of the optical detection device 2 can receive the reflected light generated after the mixed light irradiates the upper surface of the wafer 1, and generate the wafer optical data 11 according to the reflected light. The wafer optical data 11 may include, for example, the surface image of the wafer 1, the reflected brightness distribution, the grayscale distribution and / or other optical characteristic data. It is worth mentioning that the grayscale distribution can be used to eliminate the uneven brightness caused by process problems. In addition, the carrier of the optical inspection device 2 can slightly rotate the wafer 1 to make a slight change in the angle ±θ, and then the optical imaging module captures the wafer optical data 11 as the error range caused by the slight angle error to avoid misjudgment due to alignment error.

[0042] FIG. 3A to FIG. 3E FIG. 2 is a schematic diagram showing the flow of the wafer detection method of the present invention. Figure 1 and Figure 3A As shown, in step S04, a wafer (eg, a second wafer) 3 is loaded into the optical detection device 2. Wafer 3 is, for example, a semiconductor wafer identical to wafer 1, and has a patterned wafer film layer identical to wafer 1 formed thereon.

[0043] like Figure 1 , Figure 3B and Figure 3C As shown, in step S05, the wafer 3 is positioned. Figure 3BAs shown, the carrier of the optical detection device 2 can rotate, and the optical imaging module of the optical detection device 2 can automatically detect the positioning notch of the wafer 3 to perform positioning. In this embodiment, the optical imaging module of the optical detection device 2 automatically selects and detects the four corners of the wafer 3 as an example for explanation, but it is not intended to limit the present invention, and different positions can be selected and detected according to different designs. Figure 3C As shown, the carrier of the optical inspection device 2 can slightly rotate the wafer 3 to change the preset angle ±θ, and then the optical imaging module captures the wafer optical data as the error range caused by the slight angle error to avoid misjudgment due to alignment error.

[0044] like Figure 1 , Figure 3D and Figure 3E As shown, in step S06, the wafer 3 is detected, and wafer optical data 31 (for example, second wafer optical data) is generated. In some embodiments, the light source of the optical detection device 2 utilizes light with the same parameters as that of the wafer 1 to illuminate the upper surface of the wafer 3. For example, the light source of the optical detection device 2 can utilize the mixed light as described above, and illuminate the upper surface of the wafer 3 at the preset incident angle as described above. The optical imaging module of the optical detection device 2 can receive the reflected light from the upper surface of the wafer 3 to generate wafer optical data 31. In other words, the optical imaging module of the optical detection device 2 can receive the reflected light generated after the mixed light illuminates the upper surface of the wafer 3, and generate wafer optical data 31 based on the reflected light. The wafer optical data 31 may, for example, include the surface image of the wafer 3, the reflection brightness distribution, the grayscale distribution and / or other optical characteristics. As Figure 3E As shown, the wafer optical data 31 of wafer 3 may have a portion 311 that is different from the wafer optical data 11 of wafer 1. It is worth mentioning that, as mentioned above, the different portion 311 here does not include the error range caused by a slight angle error after the carrier of the optical detection device 2 slightly rotates the wafer 3.

[0045] Please refer to Figure 1 , Figure 2E and Figure 3EAs shown, in step S07, the wafer optical data 11 and the wafer optical data 31 are compared. In step S08, it is determined whether the wafer optical data 11 and the wafer optical data 31 are the same. It should be noted that in the present embodiment, wafer 1 is used as a reference wafer and wafer 3 is used as a test wafer for illustration. Therefore, the wafer optical data 11 of wafer 1 is used as the preset data to compare the difference between the wafer optical data 31 and the wafer optical data 11, and to determine whether the two are the same. It is worth mentioning that in step S06, the different characteristics of the light source of the optical detection device 2 can also be used to make the reflection or absorption brightness of the defects on the surface of the wafer 3 show obvious contrast difference with the brightness in the normal state.

[0046] It should be noted that wafer 1 and wafer 3 can be loaded into the optical detection device 2 simultaneously or separately. In other words, in some embodiments, two wafers 1 and 3 can be placed on two carriers in the optical detection device 2 at one time, with the wafer on one of the carriers being used as a reference wafer (master wafer), which is preset as a normal wafer, and the wafer on the other carrier being used as a test wafer. In other embodiments, under the architecture of a single carrier, one wafer can also be placed on the carrier in the optical detection device 2 at one time, and a wafer in the middle of the cassette can be extracted as a reference wafer (master wafer), which is preset as a normal wafer.

[0047] In some embodiments, since wafer 1 is used as a reference wafer, wafer optical data 11 can also be stored as reference data. That is, after alignment is completed, optical inspection device 2 is used for inspection, and optical data of a normal wafer (such as but not limited to wafer 1) under a light source is recorded as a reference standard. In this way, subsequent inspections can be compared by accessing wafer optical data 11.

[0048] FIG. 4A to FIG. 4D FIG. 2 is a schematic diagram showing the flow of the wafer detection method of the present invention. Figure 1 , Figure 3E and FIG. 4A to FIG. 4D As shown, in step S09, when it is determined that the wafer optical data 31 is substantially different from the wafer optical data 11, the minimum unit pattern 4 on the wafer 3 is obtained. In some embodiments, obtaining the minimum unit pattern 4 on the wafer 3 includes: reading the preset pattern data 5; obtaining at least two unit patterns 51 according to the preset pattern data 5; and obtaining the minimum unit pattern 4 according to the at least two unit patterns 51.

[0049] On the other hand, when it is determined that the wafer optical data 31 is substantially the same as the wafer optical data 11 , it means that the wafer 3 meets the specification requirements, and the next wafer can be tested.

[0050] Please refer to Figure 4AAs shown, in order to obtain the minimum unit pattern on the wafer, the preset pattern data 5 can be read first. The preset pattern data 5 is, for example, partial pattern data of a mask used to form a pattern on the wafer 3, such as pattern data of the edge of the mask, which is not intended to limit the present invention.

[0051] Please refer to Figure 4B and Figure 4C As shown, at least two unit graphics 51 are obtained according to the preset pattern data 5. As described above, after obtaining the preset pattern data 5 (e.g., pattern data of the edge of the mask), lines can be drawn along the corner points of the preset pattern data 5 to form at least two vertical lines 52 and horizontal lines 53. The at least two vertical lines 52 and horizontal lines 53 can form at least two unit graphics 51. It should be noted that the at least two unit graphics 51 do not necessarily have to be the same shape, but the at least two unit graphics 51 are composed of the minimum unit graphics.

[0052] Please refer to Figure 4D As shown, after obtaining the at least two unit figures 51 , some corner points are overlapped by rotation and translation, and the minimum unit figure 4 constituting the at least two unit figures 51 can be obtained by further overlapping the at least two unit figures 51 .

[0053] Figure 5A and Figure 5B FIG. 2 is a schematic diagram showing the flow of the wafer detection method of the present invention. Figure 1 , Figure 5A and Figure 5B As shown, in step S10, optical data of a chip unit (e.g., a first chip unit) 61 and optical data of a chip unit (e.g., a second chip unit) 62 are detected according to the minimum unit pattern 4. In step S11, the optical data of the chip unit 61 and the optical data of the chip unit 62 are compared. In some embodiments, detecting the optical data of the chip unit 61 and the optical data of the chip unit 62 include: restoring the arrangement of at least two chip units 54 of the preset pattern data 5 according to the minimum unit pattern 4; selecting the adjacent chip unit 61 and the chip unit 62 in the at least two chip units 54; and detecting the optical data of the chip unit 61 and the optical data of the chip unit 62.

[0054] Specifically, the minimum unit pattern 4 is a pattern of each chip unit 54 in the preset pattern data 5, so after obtaining the minimum unit pattern 4, the arrangement of at least two chip units 54 of the preset pattern data 5 can be restored. Then, after restoring the arrangement of the chip units 54, for the area of ​​the wafer optical data 31 in the wafer 3 that is substantially different from the wafer optical data 11, the adjacent chip unit 61 and the chip unit 62 of the at least two chip units 54 can be selected to detect the optical data of the chip unit 61 and the optical data of the chip unit 62.

[0055] In some embodiments, the wafer inspection method of the present invention further includes: determining whether the optical data of the wafer unit 61 and the optical data of the wafer unit 62 are the same; and when it is determined that the optical data of the wafer unit 62 is substantially different from the optical data of the wafer unit 61, the wafer 3 is determined to be in a defective state. Therefore, if the optical data between adjacent wafer units 61 and 62 are substantially different, it may indicate that the wafer 3 has a large variation in the process, and there are also large differences between at least two wafer units 54 of the wafer 3, so the wafer 3 can be determined to be in a defective state. Of course, the requirements for determining a defective state can be set differently according to the needs.

[0056] On the other hand, if the optical data between adjacent chip units 61 and 62 are substantially the same, it means that there is not much difference between at least two chip units 54 of wafer 3, and wafer 3 may be in a normal state, but its wafer optical data is different from the wafer optical data of the reference wafer due to some reasons (for example, different positioning angles, etc.). Therefore, it can be judged that wafer 3 is in a normal state.

[0057] It should be noted that the inspection of the adjacent chip units 61 and 62 is not limited to local inspection, and all chip units 54 of the entire wafer 3 may also be inspected as required.

[0058] It is worth mentioning that after the above-mentioned inspection, the wafer inspection method of this embodiment can also perform an automatic material number establishment process. After the process is established, the fully automatic material number establishment mode of the same state process can be executed to save the time of establishing the material number.

[0059] In summary, the wafer detection method of the present invention loads two wafers (for example, a first wafer and a second wafer) into an optical detection device and generates wafer optical data respectively. By comparing the wafer optical data of the two wafers, it can be determined whether there is a difference between the two. If it is determined that there is a difference after the detection, the optical data of each chip on one of the wafers can be compared. In other words, after the wafer detection method of the present invention has compared the wafer optical data of the first wafer (for example, as a reference wafer) and the second wafer (for example, as a test wafer), if there is a difference between the two, at least two chips on the test wafer can be further detected to determine whether the test wafer is really in a defective state. In this way, the wafer detection method of the present invention can first detect the wafer state on a large scale, and then detect the wafer details to remove the influence of slight optical property unevenness caused by the process, so as to improve the accuracy of wafer detection.

[0060] The components of several embodiments are summarized above so that those with ordinary knowledge in the technical field to which the present invention belongs can better understand the concept of the embodiments of the present invention. Those with ordinary knowledge in the technical field to which the present invention belongs should understand that the embodiments of the present invention can be used as a basis to design or modify other processes and structures to achieve the same purpose and / or achieve the same benefits as the embodiments introduced herein. Those with ordinary knowledge in the technical field to which the present invention belongs should also understand that these equivalent structures do not deviate from the spirit and scope of the present invention, and various changes, substitutions and other options can be made here without deviating from the spirit and scope of the present invention. Therefore, the scope of protection of the present invention shall be defined as the scope of the attached patent application.

Claims

1. A wafer detection method, characterized in that: It includes: Loading a first wafer into an optical inspection device; positioning the first wafer; detecting the first wafer and generating first wafer optical data; loading a second wafer into the optical inspection device; positioning the second wafer; detecting the second wafer and generating second wafer optical data; comparing the first wafer optical data and the second wafer optical data; Determining whether the first wafer optical data and the second wafer optical data are the same; When it is determined that the second wafer optical data is substantially different from the first wafer optical data, obtaining a minimum unit pattern on the second wafer; According to the minimum unit pattern, detecting the optical data of the first chip unit and the optical data of the second chip unit; and The optical data of the first chip unit and the optical data of the second chip unit are compared.

2. The wafer detection method according to claim 1, further comprising: determining whether the optical data of the first chip unit and the optical data of the second chip unit are the same; and When it is determined that the optical data of the second wafer unit is substantially different from the optical data of the first wafer unit, the second wafer is determined to be in a defective state.

3. The wafer inspection method according to claim 1, wherein: Obtaining the minimum unit pattern on the second wafer includes: Read preset pattern data; According to the preset pattern data, at least two unit graphics are obtained; The minimum unit pattern is obtained according to the at least two unit patterns.

4. The wafer inspection method according to claim 1, wherein: Detecting the optical data of the first chip unit and the optical data of the second chip unit includes: According to the minimum unit pattern, restore the arrangement of at least two chip units of the preset pattern data; Selecting the first chip unit and the second chip unit that are adjacent to each other among the at least two chip units; and The optical data of the first chip unit and the optical data of the second chip unit are detected.

5. The wafer inspection method according to claim 1, wherein: Detecting the first wafer and generating optical data of the first wafer includes: irradiating the upper surface of the first wafer with mixed light; receiving reflected light from the upper surface of the first wafer; and The first wafer optical data is generated according to the reflected light.

6. The wafer inspection method according to claim 5, wherein: Irradiating the upper surface of the first wafer with the mixed light comprises: The mixed light is used to illuminate the upper surface of the first wafer at a preset incident angle.

7. The wafer inspection method according to claim 5, wherein: The mixed light includes at least two lights with different wavelengths.

8. The wafer inspection method according to claim 1, wherein: Detecting the first wafer and generating optical data of the first wafer includes: The first wafer optical data is stored as reference data.

9. The wafer inspection method according to claim 1, wherein: The first wafer and the second wafer are loaded into the optical inspection device at the same time.

10. The wafer inspection method according to claim 1, wherein: Detecting the second wafer and generating optical data of the second wafer includes: Rotate the second wafer by a preset angle; irradiating the upper surface of the second wafer with mixed light; receiving reflected light from the upper surface of the second wafer; and The second wafer optical data is generated according to the reflected light.

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