Detection method of wafer surface film layer

Abstract

The invention provides a method for detecting a film layer on the surface of a wafer, which is used for detecting the film layer formed on the wafer, and comprises the following steps: providing incident light, and enabling the film layer to generate reflected light after receiving the incident light; and then, carrying out spectral analysis according to the reflected light, and comparing the spectral analysis with a first reference waveform so as to confirm the material of the coating layer. In addition, according to the spectral analysis of the reflected light, the reflected light is compared with a second reference waveform, so that the thickness of the coating layer is confirmed. Wherein the incident light and the reflected light are provided and received by a spectrograph which is vertically arranged on the coating layer. Through the detection method provided by the invention, the material and the film thickness of the coating layer on the upper surface of the wafer can be effectively detected and classified, the detection efficiency is greatly improved, and optimization is achieved.

Description

Technical Field

[0001] The present invention relates to a method for detecting a film layer on a wafer surface, and in particular to an operating method for detecting and classifying the material and thickness of a coating layer on a wafer surface by using a zero-degree reflection spectrometer. Background Art

[0002] In recent years, emerging technologies such as the metaverse and self-driving cars have driven the advent of new applications such as virtual reality (VR) and augmented reality (AR), making the semiconductor wafer industry increasingly prosperous in combination with optical coatings and related sensors, optical lenses, etc. Based on these new applications, the demand for semiconductor optical coatings has increased significantly, making the technology of optical coating on wafers a star in recent years.

[0003] Generally speaking, optical coating refers to coating one or more layers of dielectric film, metal film or a stack of both on different materials such as glass or wafers by evaporation or sputtering, so as to control the thickness, refractive index, absorption and other physical properties of different coating materials, so as to achieve the functional requirements of penetration, semi-transmission and reflection in specific light bands. In the past, optical coating was mostly implemented on flat materials such as glass. In recent years, with the rapid development of semiconductor processes, in order to allow the same chip (Integrated Chip, IC) to have the function of multiple photosensitive areas, wafer-level multiple optical coating technology has been born to meet the application requirements of multiple photosensitive areas on different chip designs. However, since it is known that the surface of the wafer is difficult to control in a completely flat state, the technical difficulty of directly implementing optical coating technology on the surface of the wafer and achieving the required optical properties has also increased significantly.

[0004] Since the film layers coated on the wafer may have different materials and coating thicknesses based on their actual functions and application requirements, the existing technology usually uses an ellipsometer to effectively detect and classify the film layers coated on the wafer surface. Generally speaking, the ellipsometer uses ellipsometry to measure the change between the polarization states of the medium to the incident light and the reflected light, and then calculates the optical properties of the medium. Due to its non-destructive nature and the increase in data processing speed due to the advancement of computer technology, it has been widely used in the detection of semiconductor films. Generally speaking, ellipsometry can be divided into three types according to the setting: reflection ellipsometry, transmission ellipsometry, and scattering ellipsometry. However, no matter which method is used, the change of light intensity amplitude is mainly used as the basic data for measurement, and the incident light signal is measured by rotating the light-dispersing plate. The lateral resolution of the system is about 3 microns (μm). Since these methods must find the minimum brightness or measure the change of tiny brightness, the main disadvantage is that the measurement speed is very slow. In addition, it must also cooperate with high-sensitivity photosensitive elements to measure the light intensity values ​​under multiple different light-dispersing plates, and obtain the elliptical polarization parameters through Fourier transformation or data fitting. Because the data obtained is too large (taking a single point as an example, generally 128 brightness measurements are required), the complexity of the system calculation is greatly increased, which is not only difficult but also time-consuming, and is not suitable for the development and application of the industry. In addition, after the measurement is completed, the subsequent classification of film materials is also very inconvenient and time-consuming. If there is no effective sample group for comparison and classification, the time required will increase significantly. All these shortcomings make the existing ellipsometer technology still unsuitable for practical application to this day, resulting in limited application, high cost, excessive time consumption, and low efficiency.

[0005] In view of the above, it is obvious that professionals in this field do have an urgent need to develop a novel and creative method for detecting coatings on wafers, so as to solve the problems existing in the above-mentioned prior art, so as to optimize the technical efficiency of the detection of coatings on wafers. Therefore, in consideration of the many problems listed above, it is extremely necessary to adopt various considerations, so that the inventor of the present invention, based on the areas where the above-mentioned defects can be improved, and based on years of relevant experience in this field, carefully observed and studied, and combined with theoretical application, proposed a method creation with a novel design and effective improvement of the above-mentioned defects, that is, a novel method for detecting the coating layer on the surface of the wafer. Through the method flow of the present invention, the detection of the coating layer on the surface of the wafer and the optimization and optimal benefit of its classification results can be achieved. The applicant will provide a specific architecture and implementation method, which will be described in detail below. Summary of the invention

[0006] In order to solve the above-mentioned defects, one of the purposes of the present invention is to provide an innovative method for detecting wafer surface films, which can be applied to the detection and classification of coating layers on wafers. The detection method provided by the present invention can be further widely used for mass detection, thereby meeting the technical requirements of related industries for detecting and classifying coating layers on a large number of wafers.

[0007] By adopting the detection method provided by the present invention, it can not only be applied to the detection of the coating layer on the silicon wafer. Moreover, the application of the detection method provided by the present invention is not limited to this. The detection method provided by the present invention can also be applied to the detection process of the coating layer on the wafer of various other materials. Once the disclosure of the present invention is known, other alternative and modified illustrative examples are obvious to those skilled in the art, and all belong to the scope of the invention of the present invention.

[0008] By adopting the technical solution of the wafer surface film detection method provided by the present invention, the time required for known detection can be effectively reduced, and it only takes a few tenths of a second to detect a wafer, thereby optimizing the detection efficiency. In addition, when the detection method provided by the present invention is adopted, at the same time, it can more effectively increase the classification yield of the coating detection on the wafer, so that the detection and classification efficiency of the coating layer on the wafer is optimized.

[0009] Therefore, according to an embodiment of the present invention, the detection method of the wafer surface film layer provided by the applicant is suitable for detecting a coating layer on a wafer, and the detection method mainly includes the following steps: First, an incident light is provided, and the incident light is projected onto the coating layer on the wafer to be tested, so that the coating layer generates a reflected light after receiving the incident light. Afterwards, the reflected light is received, and a spectral analysis is performed based on the reflected light. Next, the result of the spectral analysis of the reflected light is compared with the first reference waveform. When the result of the spectral analysis of the reflected light matches the first reference waveform, the output comparison is correct, and the material of the coating layer on the wafer to be tested can be confirmed.

[0010] According to an embodiment of the present invention, a spectrometer is provided for providing the incident light and receiving the reflected light. Specifically, the spectrometer is arranged directly above the wafer to be tested, so that the optical paths of the incident light and the reflected light are both perpendicular to the coating layer on the wafer to be tested. In a preferred embodiment provided by the present invention, the spectrometer can be used to provide incident light with a wavelength range of about 230 to 1000 nanometers, and the spectrometer is placed vertically directly above the wafer to be tested to provide an optical path with zero-degree reflection.

[0011] On the other hand, when the result of the spectrum analysis of the reflected light is inconsistent with the first reference waveform, the present invention establishes a new reference waveform.

[0012] At the same time, according to an embodiment of the present invention, before the result of the spectral analysis of the above-mentioned reflected light is compared with the first reference waveform, the present invention also includes: inputting the first reference waveform into the spectrometer to set its reference spectral reflectance according to the first reference waveform. For example, the reference spectral reflectance of the first reference waveform may be (-). In view of this, when the result of the spectral analysis of the reflected light shows that the spectral reflectance of the above-mentioned reflected light is greater than the reference spectral reflectance (-) of the first reference waveform, the present invention can confirm that the material of the coating layer being tested is metal. Conversely, if the result of the spectral analysis of the reflected light shows that the spectral reflectance of the reflected light is less than the reference spectral reflectance (-) of the first reference waveform, the present invention can confirm that the material of the coating layer being tested is non-metal.

[0013] Furthermore, according to the detection method provided by the present invention, the result of the spectrum analysis of the reflected light can also be further compared with the second reference waveform, and then, according to whether the result of the spectrum analysis of the reflected light is consistent with the second reference waveform, the thickness of the coating layer on the wafer can be confirmed. In this embodiment, the second reference waveform can also be pre-input into the spectrometer to set its reference spectrum recognition thickness according to the second reference waveform. For example, the reference spectrum recognition thickness of the second reference waveform can be set to 900 to 1000 nanometers.

[0014] In summary, according to the technical solution provided by the present invention, the computer unit or its algorithm can selectively classify the material of the coating layer on the wafer according to the first reference waveform, or can selectively classify the thickness of the coating layer on the wafer according to the second reference waveform. Alternatively, it can selectively classify the material of the coating layer on the wafer according to the first reference waveform and the thickness of the coating layer on the wafer according to the second reference waveform. In view of the technical solution provided by the present invention, by adopting the method for detecting the surface film layer of the wafer provided by the present invention, the overall method flow can be automated, and the classification yield of the coating detection on the wafer can be effectively increased.

[0015] It is obvious that when the technical personnel in this field understand the technical solution provided by the present invention and apply the detection method of the wafer surface film layer provided by the present invention, the problems and deficiencies existing in the prior art can be successfully eliminated. Therefore, it can be confirmed that the present invention is based on the ability to effectively increase the classification yield of the coating detection on the wafer, so that the present invention is not only highly competitive compared to the prior art, but also can be effectively and widely used in related industries. At the same time, the detection yield of the coating layer on the wafer is optimized. In summary, the present invention is highly industrially applicable and has technical competitiveness in this field.

[0016] In order to enable those skilled in the art to have a further understanding and recognition of the process steps and the effects achieved by the present invention, a preferred embodiment diagram and a detailed description are provided below. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 is a flow chart of the steps of a method for detecting a wafer surface film layer according to an embodiment of the present invention;

[0018] Figure 2 A schematic diagram of an optical path described in a method for detecting a wafer surface film layer according to an embodiment of the present invention;

[0019] Figure 3 According to the present invention Figure 1 Detailed schematic diagram of the detection method provided in the embodiment;

[0020] Figure 4 is a waveform diagram of a first reference waveform according to an embodiment of the present invention;

[0021] Figure 5 It is a schematic diagram of the spectrum analysis result of the reflected light when the coating layer is made of metal material according to an embodiment of the present invention;

[0022] Figure 6 It is a schematic diagram of the spectrum analysis result of the reflected light when the coating layer is made of metal material according to another embodiment of the present invention;

[0023] Figure 7 It is a schematic diagram of the spectrum analysis result of the reflected light when the coating layer is made of non-metallic material according to an embodiment of the present invention;

[0024] Figure 8 It is a schematic diagram of the spectrum analysis result of the reflected light when the coating layer is made of non-metallic material according to another embodiment of the present invention;

[0025] Fig. 9 is a waveform diagram of a second reference waveform according to an embodiment of the present invention;

[0026] Figures 1 to 9 Explanation of symbols: 20: spectrometer; 130: wafer to be tested; 133: coating layer; 201E: incident light; 201R: reflected light; S102, S104, S106, S108: steps; S300, S302, S304, S306, S308, S310, S312, S314, S316, S318, S320, S322, S324, S326: steps; MT: material discrimination zone; TK: thickness discrimination zone. DETAILED DESCRIPTION

[0027] The above description of the content of the present invention and the following implementation methods are used to demonstrate and explain the spirit and principle of the present invention, and provide further explanation of the scope of the patent application of the present invention. The features, implementation and efficacy of the present invention are described in detail as follows with reference to the drawings of the specification for preferred embodiments. Among them, with reference to the preferred embodiments of the present invention, examples are shown in the drawings of the specification, and in the drawings and the specification, the present invention uses the same figure marks to refer to the same or similar elements as much as possible. In the drawings and the specification, the same reference numerals represent the same or similar components. In the drawings, the shape and thickness may be exaggerated for simplification and convenience of marking. It is understood that the elements not specifically shown in the drawings or described in the specification are forms known to those of ordinary skill in the art. Those of ordinary skill in the art can make various changes and modifications based on the content of the present invention.

[0028] The following embodiments disclosed in the present invention are for illustrating the technical content and technical features of the present invention, and for enabling those skilled in the art to understand, manufacture, and use the present invention. However, it should be noted that these embodiments are not intended to limit the scope of the invention of the present invention. Therefore, any equivalent modification or variation thereof according to the spirit of the present invention should also be included in the scope of the invention of the present invention.

[0029] In the following paragraphs, the wafer surface film detection method provided by the present invention can also be applied to other related technical architectures, and the present invention is not limited to the embodiments provided below.

[0030] First, see Figure 1 As shown, it discloses a flow chart of the steps of the wafer surface film detection method of the embodiment of the present invention. According to the detection method provided by the present invention, it is suitable for detecting a wafer, especially for detecting a coating layer formed on the wafer to be tested. Generally speaking, based on the detection method disclosed by the present invention, it includes the following steps: Figure 1 The multiple steps shown are: step S102, step S104, step S106, and step S108.

[0031] First, in step S102, the present invention provides an incident light, so that the incident light can be projected onto the coating layer on the wafer, so that the coating layer generates a reflected light after receiving the incident light.

[0032] Then, in step S104, the present invention collects and receives the reflected light, and further performs spectral analysis of the reflected light according to the reflected light. After capturing the spectral analysis of the reflected light, the present invention then compares the result of the spectral analysis of the reflected light with a first reference waveform (step S106). Then, as shown in step S108, when the result of the spectral analysis of the reflected light matches and is consistent with the first reference waveform, the output is correct, thereby confirming the material of the coating layer formed on the wafer to be tested according to the first reference waveform.

[0033] Please also read Figure 2 As shown, a schematic diagram of the optical path described in the method for detecting a wafer surface film layer according to an embodiment of the present invention is disclosed. Figure 2 As shown, when the detection method disclosed in the present invention is used, a spectrometer 20 can be set, and the spectrometer 20 is set just above the wafer 130 to be tested, such as Figure 2 As shown, a coating layer 133 is formed on the wafer 130 to be tested. The spectrometer 20 is used to provide an incident light 201E. After the incident light 201E is projected onto the coating layer 133 on the wafer 130 to be tested, the coating layer 133 generates a reflected light 201R after receiving the incident light 201E. According to an embodiment of the present invention, the reflected light 201R is received by the spectrometer 20. In other words, according to the technical solution provided by the present invention, based on the fact that the spectrometer 20 is vertically arranged directly above the wafer 130 to be tested and its coating layer 133, it is obvious that the optical paths of the incident light 201E generated by the spectrometer 20 and the reflected light 201R received by the spectrometer 20 are both perpendicular to the wafer 130 to be tested and its coating layer 133. In this way, the present invention can detect the material and film thickness of the coating layer 133 by using a zero-degree reflection spectrometer 20, as described in detail later.

[0034] In detail, please refer to FIG. 3, further providing the present invention Figure 1 Detailed step diagram of the detection method disclosed in the embodiment. Figure 3 As shown, in step S300, first, a first reference waveform is input into the aforementioned spectrometer 20, and in step S302, the reference spectrum reflectance is set according to the first reference waveform. According to a preferred embodiment of the present invention, Figure 4 A waveform diagram of a first reference waveform according to an embodiment of the present invention is disclosed, as shown in FIG. 4 , the reference spectral reflectance of the first reference waveform can be determined to be “1”, for example, and Figure 4 The area shown in FIG. 1 is used as the material discrimination area MT.

[0035] In view of this, when the result of the spectral analysis of the aforementioned reflected light 201R shows that the spectral reflectivity of the reflected light 201R is greater than the reference spectral reflectivity (1) of the first reference waveform, the present invention can confirm that the material of the coating layer 133 of the wafer 130 to be tested is metal (as shown in step S304 of FIG. 3). On the other hand, if the result of the spectral analysis of the aforementioned reflected light 201R shows that the spectral reflectivity of the reflected light 201R is less than the reference spectral reflectivity (1) of the first reference waveform, the present invention determines that the material of the coating layer 133 of the wafer 130 to be tested is non-metal (as shown in step S306 of FIG. 3).

[0036] For example, please refer to the present invention Figure 5 and Figure 6 As shown, two spectral analysis results of reflected light when the coating layer is made of metal are provided. As shown in the two embodiments, the spectral reflectance is greater than 1. Therefore, the present invention can confirm that the coating layer is made of metal. Figure 7 and Figure 8 Then two other spectral analysis results of the reflected light when the coating layer is made of non-metallic material are provided. Figure 7 and Figure 8 As shown in these two embodiments, the spectral reflectance is less than 1, so the present invention can confirm that the material of the coating layer is non-metallic. In this way, by comparing the result of the spectral analysis of the reflected light with the reference spectral reflectance of the first reference waveform, the present invention can confirm the material of the coating layer on the wafer to be tested.

[0037] Afterwards, if Figure 3As shown in steps S308 to S310 in the present invention, the present invention can then provide a comparison based on the first reference waveform, and determine in step S310 whether the result of the spectral analysis of the reflected light is consistent with the first reference waveform. If the two are consistent, then in step S312, it is output that the comparison is correct; otherwise, if the result of the spectral analysis of the reflected light is inconsistent with the first reference waveform, then in step S314, another new reference waveform is established.

[0038] Furthermore, according to the detection method provided by the present invention, after the material of the coating layer on the wafer to be tested is detected and confirmed, the present invention can further compare and confirm the thickness of the coating layer. Figure 3 As shown in step S316, the present invention can also input a second reference waveform into the spectrometer, and set the reference spectrum identification thickness according to the second reference waveform. Fig. 9 As shown, it discloses a waveform diagram of a second reference waveform of an embodiment of the present invention, such as Fig. 9 As shown, it is visible enough that the reference spectrum identification thickness of the second reference waveform can be determined to be 900 to 1000 nanometers, for example, and 900 to 1000 nanometers is used as its thickness determination area TK.

[0039] Therefore, the present invention can compare the spectrum analysis result of the reflected light generated by the coating layer with the second reference waveform, and confirm the thickness of the coating layer according to whether the comparison result is consistent with the second reference waveform. In view of this, after the film thickness of the coating layer on the wafer to be tested is also detected and confirmed, the present invention can perform classification in step S318 shown in Figure 3. For example, when executing step S318, a computer unit or its processing unit (CPU) and algorithm system can be adopted to determine the classification conditions of step S320, for example: as shown in step S322: classify the material of the coating layer on the wafer according to the first reference waveform. Or, as shown in step S324: classify the thickness of the coating layer on the wafer according to the second reference waveform. Or, as shown in step S326: classify the material of the coating layer on the wafer according to the first reference waveform, and classify the thickness of the coating layer on the wafer according to the second reference waveform.

[0040] It is worth reminding that the classification conditions provided above are only a few implementation modes of the present invention. A technician with general knowledge in the field can naturally change or modify them according to the types of wafers to be tested and their coating layers and the actual application requirements. However, the present invention is not limited to the conditions listed in the exemplary examples listed in this application.

[0041] In view of the above, it is clear that the purpose of the invention of the present invention is to use a method for detecting the film layer on the surface of a wafer proposed by the applicant, which uses a spectrometer that can be used to provide incident light in a wavelength range of, for example, about 230 to 1000 nanometers, and vertically places it just above the coating layer of the wafer to be detected to provide an optical path with zero degree reflection. In this way, after the spectrometer receives the reflected light generated by the coating layer of the wafer to be detected, it analyzes and compares it, and the present invention can find out the material (material) and film thickness (thickness) of the coating layer on the wafer to be detected.

[0042] The advantages of the above technical solution provided by the present invention are that the overall operation method and its process can be automated, and the disclosed method and process can effectively reduce the time required for detection, and it only takes a few tenths of a second to detect a wafer, thereby maximizing the detection efficiency. In addition, according to the detection method disclosed by the present invention, the classification yield of the coating detection on the wafer can be further effectively increased and optimized.

[0043] Therefore, in view of the above technical solutions provided by the applicant, it is obvious that the present invention aims to provide an innovative method for detecting wafer surface films, which can not only effectively meet the technical requirements of the current industry for mass detection of a large number of wafers, but also effectively improve the competitiveness of its industrial production. Under this circumstance, it is obvious that the present invention actually has a very significant invention effect.

[0044] Compared with the prior art, it is obvious that the embodiments disclosed in the present invention and the operation methods thereof can effectively solve many deficiencies in the prior art and provide better detection and classification results. Moreover, the technical solution provided by the present invention can be applied not only to common silicon wafers, but also to various electronic circuit elements such as the semiconductor industry, integrated circuit industry, or power electronics. It is obvious that the technical solution provided by the applicant in the present invention does have excellent industrial applicability and competitiveness. At the same time, the technical features, methods and effects achieved by the present invention are significantly different from the current solutions, and are not something that can be easily accomplished by those familiar with the technology, but should have patent requirements.

[0045] The embodiments described above are only for illustrating the technical ideas and features of the present invention, and their purpose is to enable technicians familiar with the present invention to understand the contents of the present invention and implement them accordingly. They cannot be used to limit the patent scope of the present invention. That is, all equivalent changes or modifications made according to the spirit provided by the present invention should still be included in the patent scope of the present invention.

Claims

1. A method for detecting a film layer on a wafer surface, suitable for a wafer having a coating layer formed thereon, the method comprising: Providing an incident light, wherein the incident light is projected onto the coating layer on the wafer, so that the coating layer generates a reflected light after receiving the incident light; receiving the reflected light, and performing spectral analysis based on the reflected light; The result of the spectral analysis of the reflected light is compared with a first reference waveform; and when the result of the spectral analysis of the reflected light matches the first reference waveform, the output is that the comparison is correct, thereby confirming the material of the coating layer on the wafer.

2. The method for detecting a wafer surface film layer according to claim 1, further comprising: When the result of the spectrum analysis of the reflected light is inconsistent with the first reference waveform, a new reference waveform is established.

3. The method for detecting a wafer surface film layer as claimed in claim 1, wherein: The incident light is provided by a spectrometer.

4. The method for detecting a wafer surface film layer as claimed in claim 3, wherein: The reflected light is received by the spectrometer.

5. The method for detecting a wafer surface film layer as claimed in claim 3, wherein: The spectrometer is arranged right above the wafer, so that the optical paths of the incident light and the reflected light are both perpendicular to the coating layer on the wafer.

6. The method for detecting a wafer surface film layer as claimed in claim 3, wherein: Before comparing the result of the spectrum analysis of the reflected light with the first reference waveform, the method further includes: The first reference waveform is input into the spectrometer; and a reference spectrum reflectance of the first reference waveform is set according to the first reference waveform.

7. The method for detecting a wafer surface film layer as claimed in claim 6, wherein: When the result of the spectrum analysis of the reflected light shows that the spectral reflectance of the reflected light is greater than the reference spectral reflectance of the first reference waveform, it is confirmed that the material of the coating layer is metal.

8. The method for detecting a wafer surface film layer as claimed in claim 6, wherein: When the result of the spectrum analysis of the reflected light shows that the spectral reflectance of the reflected light is less than the reference spectral reflectance of the first reference waveform, it is confirmed that the material of the coating layer is non-metal.

9. The method for detecting a wafer surface film layer as claimed in claim 6, wherein: The reference spectral reflectance of the first reference waveform is one.

10. The method for detecting a wafer surface film layer as claimed in claim 1, further comprising: Comparing the result of the spectrum analysis of the reflected light with a second reference waveform; And whether the result of the spectrum analysis of the reflected light is consistent with the second reference waveform, thereby confirming the thickness of the coating layer on the wafer.

11. The method for detecting a wafer surface film layer according to claim 10, further comprising: inputting the second reference waveform into a spectrometer; and setting a reference spectrum identification thickness of the second reference waveform according to the second reference waveform.

12. The method for detecting a wafer surface film layer as claimed in claim 11, wherein: The incident light is provided by the spectrometer.

13. The method for detecting a wafer surface film layer as claimed in claim 11, wherein: The reflected light is received by the spectrometer.

14. The method for detecting a wafer surface film layer as claimed in claim 11, wherein: The spectrometer is arranged right above the wafer, so that the optical paths of the incident light and the reflected light are both perpendicular to the coating layer on the wafer.

15. The method for detecting a wafer surface film layer as claimed in claim 11, wherein: The reference spectrum identification thickness of the second reference waveform is 900 to 1000 nanometers.

16. The method for detecting a wafer surface film layer as claimed in claim 11, wherein: A computer unit may selectively classify the material of the coating layer on the wafer according to the first reference waveform, and may selectively classify the thickness of the coating layer on the wafer according to the second reference waveform.

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