Detection method of wafer front surface film layer

Abstract

To provide a detection method of a wafer front surface film layer.SOLUTION: A detection method of a wafer front surface film layer according to the present invention performs detection for a coating layer formed onto a wafer. The detection method contains steps of: providing incident light, and generating reflection light after reception of the incident light by the coating layer; and performing a spectrum analysis on the basis of the reflection light after that, and confirming a material of the coating layer by comparing it with a first reference waveform. Also, the detection method of the wafer front surface film layer contains a step of comparing it with a second reference waveform on the basis of the spectrum analysis of the reflection light, and further confirming a thickness of the coating layer. All of the incident light and the reflection light are provided and received by a spectrometer installed vertical to the coating layer. By the detection method disclosed in the present invention, the material and the film thickness of a front surface coating layer on the wafer can be effectively detected and classified; a detection efficiency is largely improved as compared with the conventional detection efficiency; and an optimization is achieved.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] The present invention relates to a method for detecting a film layer on a wafer surface, and more particularly to an operating method for detecting and classifying the material and thickness of a coating layer on a wafer surface by using a spectrometer that reflects at 0 degrees. [Background technology]

[0002] In recent years, emerging technologies such as the metaverse and autonomous driving have expanded new applications to virtual reality, augmented reality, etc., and the semiconductor wafer industry is combining optical coatings and related sensors, optical lenses, etc., creating more and more business opportunities. These new applications have increased the demand for semiconductor optical coatings, and wafer optical coating technology has been attracting attention in recent years. Summary of the Invention [Problem to be solved by the invention]

[0003] In general, optical coating is performed by plating one or more layers of dielectric films, metal films, or a film stack consisting of both on different materials such as glass or wafers using processes such as evaporation and sputtering, and controlling the physical properties such as thickness, refractive index, and absorption of different coating materials to achieve functions such as transmission, semi-transmission, semi-reflection, and reflection of a specific light wavelength band. Most of the conventional optical coatings are applied to flat materials such as glass, and in recent years, with the rapid progress of semiconductor processes, wafer-level multi-optical coating technology has been developed to provide the function of multiple photosensitive regions in the same chip, thereby meeting the demand for multiple photosensitive regions in different chip designs. However, it is very difficult to control the surface of known wafers to be completely flat, and it is very technically difficult to directly apply optical coating technology to the wafer surface to achieve the required optical properties.

[0004] The film layers plated on the wafer are selected with different materials and coating thicknesses according to the actual functions and application demands. In order to effectively detect and classify the coating layers on the wafer surface, the conventional technology usually uses ellipsometry to detect them. The ellipsometer usually employs ellipsometry to estimate the optical properties of the medium by measuring the changes in the polarization state of the incident and reflected light. Due to its non-destructive characteristics and the improvement of data processing speed due to the advancement of computer technology, it is now widely used in the detection of semiconductor films. Generally, ellipsometry can be divided into three types: reflection ellipsometry, transmission ellipsometry, and scattering ellipsometry. However, all of these methods mainly use the change in the amplitude of light intensity as the basic data for measurement, and the measurement is performed by modulating the incident light signal by rotating the analyzer, and the lateral resolution of the system is about 3 μm. All of these methods need to find the minimum light brightness or measure minute changes in brightness, so the main drawback is that the measurement speed is very slow. In addition, it is necessary to combine highly sensitive photosensitive elements, measure the light intensity values ​​at multiple different analyzers, and calculate the ellipsoidal polarization parameters through Fourier transformation or data fitting. If the data obtained is too large (taking a single point as an example, it is generally necessary to measure 128 brightnesses), the system calculation becomes more complex, which is difficult and time-consuming, and is not suitable for the development of applications in the industrial world. In addition, after the measurement is completed, the subsequent classification of the film layer materials is also inconvenient and time-consuming, and the comparison and classification of sample groups cannot be performed efficiently, which takes even more time. Due to these drawbacks, traditional ellipsometer technology is still not suitable for practical applications to this day, and its applications are limited, and there are problems such as being too expensive, too time-consuming, and inefficient.

[0005] As described above, there is a need for experts in this field to develop a new and creative method for detecting coating on a wafer, to solve the problems existing in the prior art described above, and to optimize the efficiency of the technology for detecting coating on a wafer. Therefore, in consideration of the above problems and in light of various aspects, the inventor of the present invention believes that the above shortcomings can be improved, and based on his many years of experience in this field, he focuses on observation and research, incorporates scientific theory, and puts forward the present invention, which improves the above shortcomings through a new design, and provides a new method for detecting a coating layer on a wafer surface. In order to optimize the detection and classification results of a coating layer on a wafer surface and achieve the best effect through these innovative methods, the applicant provides specific mechanisms and implementation methods, which are described in detail below.

[0006] The present invention has been made in view of the above circumstances, and aims to solve the above problems as an example of the objective of the present invention. That is, an object of the present invention is to provide a novel method for detecting a film on a wafer surface. This detection method is applied to the detection and classification of coating layers on a wafer. The detection method disclosed in the present invention can be more widely applied to mass detection, thereby satisfying the technical demand in related industries for the detection and classification of coating layers on a large number of wafers.

[0007] The detection method described in the present invention is applied to the detection of the coating layer of a silicon wafer. However, it is obvious that the application of the present invention is not limited thereto. The detection method of the present invention can be applied to the detection process of the coating layer of a wafer made of various other materials. After understanding the contents disclosed in this application, other alternatives and modifications will be obvious to those skilled in the art, and all are within the scope of the present invention.

[0008] By adopting the method for detecting the film layer on the wafer surface disclosed in the present invention, the time required by the conventional detection method can be effectively shortened, and the detection of one wafer takes only a few tenths of a second, optimizing the detection efficiency. In addition, by implementing the detection method of the present invention, the yield rate of wafer coating detection and classification is improved, and the efficiency of wafer coating layer detection and classification is optimized. [Means for solving the problem]

[0009] In order to solve the above problems, a method for detecting a wafer surface film layer according to an embodiment of the present invention is adapted to detect a coating layer on a wafer. The detection method mainly includes the following steps: First, provide incident light, which is projected onto the coating layer on the wafer, and the coating layer generates reflected light after receiving the incident light. Then, receive the reflected light and perform a spectrum analysis based on the reflected light. Next, compare the spectrum analysis result of the reflected light with a first reference waveform. If the spectrum analysis result of the reflected light matches the first reference waveform, output that the comparison is accurate, and confirm the material of the coating layer on the inspected wafer.

[0010] According to an embodiment of the present invention, a spectrometer is used to provide the incident light and receive the reflected light. Specifically, the spectrometer is placed directly above the wafer, and the optical paths of the incident light and the reflected light are all perpendicular to the coating layer on the wafer. In a preferred embodiment of the present invention, the spectrometer provides incident light, for example, in a wavelength range of about 230-1000 nm, and the spectrometer is positioned perpendicular to the wafer to be detected, providing an optical path that reflects at 0 degrees.

[0011] On the other hand, if the spectrum analysis result of the reflected light does not match the first reference waveform, the present invention further constructs a new reference waveform.

[0012] According to an embodiment of the present invention, before comparing the spectral analysis result of the reflected light with the first reference waveform, the present invention further includes the step of inputting the first reference waveform into a spectrometer and setting a reference spectral reflectance based on the first reference waveform. For example, the reference spectral reflectance of the first reference waveform is, for example, 1. In view of this, if the spectral analysis result of the reflected light indicates that the spectral reflectance of the reflected light is greater than the reference spectral reflectance (1) of the first reference waveform, the present invention confirms that the material of the coating layer detected is metallic. If the spectral analysis result of the reflected light indicates that the spectral reflectance of the reflected light is less than the reference spectral reflectance (1) of the first reference waveform, the present invention further confirms that the material of the coating layer detected is non-metallic.

[0013] More specifically, according to the detection method of the present invention, the spectral analysis result of the reflected light is further compared with a second reference waveform progression, and then the thickness of the coating layer on the wafer is confirmed based on whether the spectral analysis result of the reflected light is consistent with the second reference waveform. In this embodiment, the second reference waveform is inputted into a spectrometer in advance, and a reference spectral discrimination thickness is set based on the second reference waveform. For example, the reference spectral discrimination thickness of the second reference waveform is set in the range of 900 to 1000 nm.

[0014] In this way, based on the technical method disclosed in the present invention, a computer unit or a calculation method can arbitrarily classify the "material" of the coating layer on the wafer based on the first reference waveform, or arbitrarily classify the "thickness" of the coating layer on the wafer based on the second reference waveform. Alternatively, the "material" of the coating layer on the wafer can be arbitrarily classified based on the first reference waveform, and the "thickness" of the coating layer on the wafer can be arbitrarily classified based on the second reference waveform. In view of the technical method disclosed in the present invention, by adopting the method for detecting a wafer surface film layer described in the present invention, the automation of the flow chart of the entire method is achieved, and the yield of the classification of the coating detection on the wafer is effectively improved. Effect of the Invention

[0015] In this way, those skilled in the art can understand the technical method disclosed in the present invention and solve the problems and shortcomings existing in the prior art when applying the method for detecting a film layer on a wafer surface disclosed in the present invention. Therefore, the present invention can effectively improve the classification yield of coating detection on a wafer, so that the present invention is not only more competitive than the prior art, but also can be widely and effectively used in related industries. It also achieves optimization in the yield of detecting a coating layer on a wafer. In summary, the present invention has extremely high industrial applicability and technical competitiveness in this field. [Brief description of the drawings]

[0016] [Figure 1] 1 is a flowchart showing a method for detecting a wafer surface film layer according to an embodiment of the present invention. [Diagram 2] 1 is a schematic diagram showing an example of an optical path described in a method for detecting a film layer on a surface of a wafer according to an embodiment of the present invention. [Diagram 3] FIG. 2 shows a block diagram of detailed steps of the disclosed detection method according to an embodiment of the present invention; [Figure 4] 2A and 2B are schematic diagrams of waveform diagrams of a first reference waveform according to an embodiment of the present invention; [Diagram 5] 4 is a schematic diagram illustrating a spectroscopic analysis result of reflected light when a coating layer is made of a metal material according to an embodiment of the present invention. [Figure 6] 13 is a schematic diagram illustrating a spectroscopic analysis result of reflected light when a coating layer is made of a metal material according to another embodiment of the present invention. [Figure 7] 4 is a schematic diagram illustrating a spectroscopic analysis result of reflected light when a coating layer is a non-metallic material according to an embodiment of the present invention. [Figure 8] 13 is a schematic diagram illustrating a spectroscopic analysis result of reflected light when a coating layer is a non-metallic material according to another embodiment of the present invention. [Figure 9] 4A and 4B are schematic diagrams of waveform diagrams of a second reference waveform according to an embodiment of the present invention; DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0017] The above and the following embodiments are disclosed to explain the spirit of the present invention and to interpret the claims of the present invention in more detail. Hereinafter, the features, examples, and effects of the present invention will be described with reference to the drawings and examples. Hereinafter, reference will be made to preferred embodiments of the present invention (examples of which are shown in the accompanying drawings), and in the accompanying drawings and the specification, the present invention will use the same notations to refer to the same or similar components as much as possible. Hereinafter, the embodiments of the present invention will be described with reference to the drawings. In the drawings and the specification, the same reference numerals indicate the same or similar components. In the drawings, the shapes and thicknesses may be enlarged for simplification or convenience of illustration. It should be noted that elements not shown in the drawings or described in the specification are obvious to those skilled in the art. Those skilled in the art can make various changes and improvements based on the contents of the present invention. The following embodiments of the present invention are disclosed for the purpose of describing the technical content and technical features of the present invention, and for the purpose of 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 present invention. Therefore, equivalent modifications or variations thereof that comply with the spirit of the present invention should also be included in the scope of the present invention described herein.

[0018] Hereinafter, an embodiment of the method for detecting a wafer surface film layer of the present invention will be described with reference to the drawings. However, the present invention is not limited to these embodiments, and the members, materials, etc. described below can be modified in various ways within the scope of the spirit of the present invention.

[0019] Fig. 1 is a flow chart showing a method for detecting a film layer on a wafer surface according to an embodiment of the present invention. The detection method disclosed in the present invention is suitable for detecting a wafer, and in particular, detects the film layer for a coating layer formed on the wafer to be inspected. Generally, the detection method disclosed in the present invention includes steps S102, S104, S106, and S108 shown in Fig. 1. Each of these steps will be described below.

[0020] First, in step S102, the present invention provides incident light, which is projected onto a coating layer on the wafer, and the coating layer generates a reflected light after receiving the incident light.

[0021] Then, in step S104, the present invention collects and receives the reflected light, and further performs a spectral analysis of the reflected light based on the reflected light. After capturing the spectral analysis of the reflected light, the present invention compares the spectral analysis result of the reflected light with a first reference waveform (step S106). Then, as shown in step S108, if the spectral analysis result of the reflected light matches the first reference waveform, the present invention outputs that the comparison is accurate, and identifies the material of the coating layer formed on the inspected wafer based on the first reference waveform.

[0022] Also refer to FIG. 2, which shows an example of an optical path described in the method for detecting a wafer surface film layer according to an embodiment of the present invention. As shown in FIG. 2, when the detection method according to the present invention is adopted, a spectrometer 20 is installed, and the spectrometer 20 is installed directly above the wafer 130 to be inspected (see FIG. 2), on which a coating layer 133 is formed. The spectrometer 20 is used to provide an incident light 201E, which is projected onto the coating layer 133 on the wafer 130 to be inspected, and then 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 method of the present invention, the spectrometer 20 is vertically installed directly above the inspected wafer 130 and its coating layer 133, and obviously, the present invention controls the optical paths of the incident light 201E generated by the spectrometer 20 and the reflected light 201R received by the spectrometer 20 to be perpendicular to the inspected wafer 130 and its coating layer 133. In this way, the present invention employs the spectrometer 20 reflecting at 0 degrees to detect the material and thickness of the coating layer 133 (details will be described later).

[0023] In detail, FIG. 3 shows a block diagram of detailed steps of the disclosed detection method according to the embodiment of FIG. 1 of the present invention. As shown in FIG. 3, in step S300, a first reference waveform is first input to the spectrometer 20. In step S302, a reference spectral reflectance is set based on the first reference waveform. According to a preferred embodiment of the present invention, FIG. 4 shows a schematic waveform diagram of a first reference waveform according to an embodiment of the present invention. The reference spectral reflectance of the first reference waveform is determined to be, for example, "1", and the area shown in the figure is set as a material identification area MT (see FIG. 4).

[0024] Here, if the result of the spectrum analysis of the reflected light 201R indicates that the spectral reflectance of the reflected light 201R is greater than the reference spectral reflectance (1) of the first reference waveform, the present invention confirms that the material of the coating layer 133 of the inspected wafer 130 is metallic (as shown in step S304 of FIG. 3). On the other hand, if the result of the spectrum analysis of the reflected light 201R indicates that the spectral reflectance of the reflected light 201R is less than the reference spectral reflectance (1) of the first reference waveform, the present invention determines that the material of the coating layer 133 of the inspected wafer 130 is non-metallic (as shown in step S306 of FIG. 3).

[0025] For example, as shown in Figures 5 and 6, the spectral analysis results of the reflected light of two types of coating layers made of metal materials are shown, and as shown in the two examples, the spectral reflectances are both greater than 1, so that the present invention confirms that the material of the coating layer is metal. In comparison, as shown in Figures 7 and 8, the spectral analysis results of the reflected light of two other types of coating layers made of non-metallic materials are shown, and as shown in the two examples of Figures 7 and 8, the spectral reflectances are both less than 1, so that the present invention confirms that the material of the coating layer is non-metal. In this way, after comparing the spectral analysis result of the reflected light with the reference spectral reflectance of the first reference waveform, the present invention can confirm what the "material" of the coating layer on the inspected wafer is.

[0026] 3, the present invention then provides a comparison based on a first reference waveform, and judges whether the spectrum analysis result of the reflected light is consistent with the first reference waveform in step S310. If the two are consistent, output that the comparison is accurate in step S312. Otherwise, if the spectrum analysis result of the reflected light is inconsistent with the first reference waveform, further construct a new reference waveform in step S314.

[0027] More specifically, according to the detection method of the present invention, after the detection and confirmation of the "material" of the coating layer on the wafer to be inspected is completed, the present invention further compares and confirms its thickness with the "film thickness" of the coating layer. Specifically, refer to step S316 shown in FIG. 3, in said step, the present invention also inputs a second reference waveform into the spectrometer, and sets its reference spectrum discrimination thickness according to the second reference waveform. FIG. 9 is a schematic diagram of a waveform diagram of a second reference waveform according to an embodiment of the present invention. The reference spectrum discrimination thickness of the second reference waveform is determined to be, for example, in the range from 900 to 1000 nm, and the range from 900 to 1000 nm is set as the thickness determination area TK (see FIG. 9).

[0028] Therefore, the present invention compares the spectrum analysis result of the reflected light generated by the coating layer with the second reference waveform, and confirms the thickness of the coating layer based on whether the comparison result is consistent with the second reference waveform. Here, after the detection and confirmation of the "film thickness" of the coating layer on the wafer to be inspected is completed, the present invention performs classification in step S318 shown in FIG. 3. For example, when performing step S318, a computer unit or a central processing unit (CPU) and a calculation method are adopted to determine the classification condition in step S320. For example, as shown in step S322, the "material" of the coating layer on the wafer is classified based on the first reference waveform. Or, as shown in step S324, the "thickness" of the coating layer on the wafer is classified based on the second reference waveform. Or, as shown in step S326, the "material" of the coating layer on the wafer is classified based on the first reference waveform, and at the same time, the "thickness" of the coating layer on the wafer is classified based on the second reference waveform.

[0029] It should be noted that the above classification conditions are merely some embodiments of the present invention, and a person having ordinary skill in the art may make changes or modifications according to the type of wafer and its coating layer to be inspected and the actual application, and the present invention is not limited to the several conditions exemplified in this application.

[0030] As described above, the present invention intends to use the method of detecting a wafer surface film layer described herein, for example, to utilize a spectrometer that is vertically positioned directly above the coating layer of the wafer to be detected and provides incident light in the wavelength range of about 230 to 1000 nm, and provides an optical path that reflects at 0 degrees. In this way, the spectrometer receives the reflected light generated by the coating layer of the wafer to be detected, and then analyzes and compares it. The present invention finds the material and thickness of the coating layer on the wafer to be detected.

[0031] The technical advantages of the present invention are that it achieves automation of the overall operation method and flow chart, and by using the method flow chart provided, it effectively shortens the time required for traditional detection, so that the detection of one wafer only takes a few tenths of a second, optimizing the detection efficiency. In addition, based on the detection method of the present invention, the yield of the classification of the detected coating on the wafer is further improved and optimized.

[0032] In view of the technical methods provided in the above specification, it is evident that the novel wafer surface film layer detection method of the present invention can meet the technical demand for performing detection on a large number of wafers required in the current industry, and effectively improve the competitiveness of industrial productivity. In this context, the present invention has a very significant inventive effect.

[0033] Compared with the prior art, the embodiments and operation methods disclosed in the present invention can effectively solve many of the shortcomings in the prior art and provide better detection and classification results. In addition, based on the technical method of the present invention, it can be widely applied not only to general silicon wafers but also to related semiconductor industry, integrated circuit industry, or various electronic circuit elements such as power electronics. It is clear that the technical solutions disclosed in this specification have excellent industrial usefulness and competitiveness. At the same time, the technical features, methods and effects disclosed in the present invention are significantly different from existing solutions, and even those skilled in the art cannot easily achieve them.

[0034] The present invention can be implemented in various other forms without departing from its spirit or main features. Therefore, the above-described embodiments are merely illustrative in all respects and should not be interpreted as being limiting. The scope of the present invention is defined by the claims and is not limited to the text of the specification. Furthermore, all modifications and changes within the scope of the claims are within the scope of the present invention. [Explanation of symbols]

[0035] 20 spectrometer 130 Wafer to be inspected 133 Coating Layer 201E Incident light 201R Reflected Light S102~S108 Steps S300~S326 Step MT Material Identification Area TK Thickness Judgment Area

Claims

1. A method for detecting a wafer surface film layer applied to a wafer having a coating layer formed thereon, comprising the steps of: providing incident light, the incident light being projected onto the coating layer on the wafer, the coating layer receiving the incident light and then generating reflected light; receiving the reflected light and performing a spectral analysis based on the reflected light; comparing a spectral analysis result of the reflected light with a first reference waveform; and if the spectral analysis result of the reflected light matches the first reference waveform, outputting that the comparison is accurate, thereby confirming the material of the coating layer on the wafer.

2. 2. The method for detecting a wafer surface film layer according to claim 1, further comprising the step of constructing a new reference waveform when the spectrum analysis result of the reflected light does not match the first reference waveform.

3. 2. The method for detecting a wafer surface film layer according to claim 1, wherein the incident light is provided from a spectrometer.

4. 4. The method for detecting a wafer surface film layer according to claim 3, wherein the reflected light is received by the spectrometer.

5. 4. The method for detecting a wafer surface film layer according to claim 3, wherein the spectrometer is placed directly above the wafer, and the optical paths of the incident light and the reflected light are all perpendicular to the coating layer on the wafer.

6. prior to comparing the spectral analysis of the reflected light with the first reference waveform; inputting the first reference waveform into the spectrometer; 4. The method for detecting a wafer surface film layer according to claim 3, further comprising: setting a reference spectral reflectance of the first reference waveform based on the first reference waveform.

7. 7. The method for detecting a wafer surface film layer according to claim 6, wherein if the result of the spectral analysis of the reflected light indicates that the spectral reflectance of the reflected light is greater than the reference spectral reflectance of the first reference waveform, the material of the coating layer is confirmed to be metal.

8. 7. The method for detecting a wafer surface film layer according to claim 6, wherein, in the result of the spectral analysis of the reflected light, if the spectral reflectance of the reflected light is smaller than the reference spectral reflectance of the first reference waveform, it is confirmed that the material of the coating layer is non-metallic.

9. 7. The method for detecting a wafer surface film layer according to claim 6, wherein the reference spectral reflectance of the first reference waveform is 1.

10. comparing the spectral analysis of the reflected light with a second reference waveform; 2. The method for detecting a wafer surface film layer according to claim 1, further comprising a step of confirming a thickness of the coating layer on the wafer based on whether the spectral analysis result of the reflected light matches the second reference waveform.

11. inputting the second reference waveform into a spectrometer; 11. The method of claim 10, further comprising: setting a reference spectral discrimination thickness of the second reference waveform based on the second reference waveform.

12. The method for detecting a wafer surface film layer according to claim 11, wherein the incident light is provided by the spectrometer.

13. The method for detecting a wafer surface film layer according to claim 11, wherein the reflected light is received by the spectrometer.

14. 12. The method for detecting a wafer surface film layer according to claim 11, wherein the spectrometer is placed directly above the wafer, and the optical paths of the incident light and the reflected light are all perpendicular to the coating layer on the wafer.

15. 12. The method for detecting a wafer surface film layer as claimed in claim 11, wherein the reference spectral discrimination thickness of the second reference waveform is from 900 to 1000 nm.

16. The method for detecting a wafer surface film layer according to claim 11, characterized in that a computer unit arbitrarily classifies the material of the coating layer on the wafer based on the first reference waveform, and arbitrarily classifies the thickness of the coating layer on the wafer based on the second reference waveform.

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