EPD detection method based on laser reflection signal during ICP etching

Abstract

The invention provides an EPD detection method based on a laser reflection signal during ICP etching, and relates to the technical field of semiconductor manufacturing. The EPD detection method comprises the following steps: arranging a distributed covering mask material on an epitaxial material to form an etching monitoring area in which a covering area and an exposed area alternately exist; iCP plasma etching is carried out, and light wave signals generated by laser end point monitoring reflection and / or refraction are obtained to form a process signal curve; and determining the etching depth of the epitaxial material in the etching monitoring area according to the process signal curve. According to the method provided by the invention, a regular laser end point monitoring reflection oscillogram can be generated during dry etching of a material with a complex structure, so that the etching depth can be judged more accurately and finely.

Description

Technical Field

[0001] The invention relates to the technical field of semiconductor manufacturing, and in particular to an EPD detection method based on laser reflection signals during ICP etching. Background Art

[0002] In the field of semiconductor manufacturing, precise etching process is one of the key steps in producing high-performance electronic devices. In particular, inductively coupled plasma etching (ICP) technology has been widely used in the manufacture of semiconductor devices due to its high controllability and ability to be applied to complex material structures. In the ICP etching process, in order to monitor the etching depth and ensure the consistency and repeatability of the process, laser detection (EPD) technology is usually used. This technology generates a process signal curve representing the etching process by analyzing the signal waveform and intensity changes generated by the refraction, reflection and interference phenomena of the laser on the surface and interface of the material.

[0003] Although EPD technology provides an effective means of monitoring the etching process, there are still some limitations in existing practice. The EPD detection currently used usually relies on a preset detection area that must be larger than a certain specified size (such as a square or circle) to ensure that the laser spot is completely located within the opening. This method can obtain a regular waveform diagram, which can assist the operator in judging the etching depth of the material. However, this standardized detection method is mainly suitable for materials with relatively single optical properties, and has requirements on the size of the monitoring area, which must be larger than a certain minimum size.

[0004] Existing EPD technology often has difficulty dealing with complex multilayer structure materials, especially those semiconductor layers composed of alternating materials with different refractive indices, such as nano-thin film stacks composed of III-V elements. In these materials, the changes in optical properties caused by non-uniform doping and complex multilayer structures make it impossible for the original laser reflection and interference patterns to form a regular waveform. In this case, the traditional EPD detection method cannot effectively reflect the etching depth, resulting in inaccuracy in the etching process control, thus affecting the quality and performance of the final product.

[0005] In summary, although the existing EPD technology plays an important role in semiconductor manufacturing, its limitations in processing complex material structures are still significant. Especially in the etching process of multi-layer heterostructures, the traditional EPD method often cannot provide accurate etching depth information because it cannot adapt to the non-singularity of the optical properties of the material. This defect limits the accuracy and efficiency of the semiconductor manufacturing process, and more advanced solutions are needed to overcome these technical challenges in order to improve the manufacturing quality and performance of the device.

[0006] In view of this, the present invention is proposed. Summary of the invention

[0007] The object of the present invention is to provide an EPD detection method based on laser reflection signals during ICP etching, wherein the EPD detection method can generate a regular waveform when dry etching materials with complex structures (such as alternating growth or materials with no fixed refractive index), thereby accurately determining the etching depth.

[0008] In order to achieve the above-mentioned purpose of the present invention, the following technical solutions are particularly adopted:

[0009] The present invention provides an EPD detection method based on a laser reflection signal during ICP etching, comprising:

[0010] On the epitaxial material, a mask material is provided which is distributed and covers the surface of the epitaxial material, so as to form an etching monitoring area where a covered area based on the mask material and an exposed area not covered by the mask material alternately and periodically exist;

[0011] Performing ICP plasma etching on the etching monitoring area; and obtaining light wave signals generated by reflection and / or refraction of laser endpoint monitoring to form a process signal curve;

[0012] An etching depth of the epitaxial material in the etching monitoring area is determined according to the process signal curve.

[0013] In an optional embodiment, the mask material has a uniform structure and a single refractive index.

[0014] In an optional embodiment, the laser emitted by the etching endpoint monitor EPD configured for the ICP etcher that irradiates the mask material and the epitaxial material at the same time, and the reflected and / or refracted light waves can be superimposed.

[0015] In an optional embodiment, the mask material includes SiO x 、SiO x N y 、SiN x and SiN x H y At least one of .

[0016] In an optional embodiment, the mask material is formed into the covering area by a plurality of covering units independently covering the surface of the epitaxial material;

[0017] The exposed area not covered by the mask material is arranged between the covering units.

[0018] In an optional embodiment, a plurality of the covering units constitute the covering area of ​​an array structure.

[0019] In an optional implementation, the spacing between each of the covering units is 1 μm to 20 μm.

[0020] In an optional embodiment, the shape of the covering unit includes at least one of a rectangle, a diamond, a circle, and an arc.

[0021] In an optional embodiment, a mask material distributedly covering the surface of the epitaxial material is arranged on the epitaxial material to form an etching monitoring area in which a covered area based on the mask material and an exposed area not covered by the mask material alternately and periodically exist, including:

[0022] Delineating the etching monitoring area at the corresponding area set on the photomask; wherein the etching monitoring area includes a covered area and an exposed area;

[0023] Growing the mask material on the surface of the epitaxial material to form a composite sheet source;

[0024] The composite source is photolithographically processed using the photomask, and then the unprotected mask material is removed to form the etching monitoring area where the covered area covered by the mask material and the exposed area not covered by the mask material alternately exist.

[0025] Compared with the prior art, the present invention has the following beneficial effects:

[0026] By setting SiO x and SiO x N y , SiN x , SiN x H y Mask materials such as SiO2 and SiO3 are used to form an etching monitoring area with alternating covered areas and exposed areas, so that the laser can simultaneously irradiate the epitaxial material and SiO2 during the etching process. x and SiO x N y , SiN x , SiN x H y The mask materials are the same as those of the conventional ones, so that the superposition of the reflected and refracted light waves of the two materials can produce a regular waveform with obvious signals, thereby improving the accuracy of etching depth detection.

[0027] This method is particularly suitable for materials with complex structures, such as multi-layer materials composed of III-V group elements or material structures with no fixed refractive index due to non-single doping. It is difficult to obtain regular waveforms for these materials using traditional EPD detection methods. The present invention can effectively solve this problem and greatly increase the range of applicable materials.

[0028] By introducing SiO x 、SiOx N y 、SiN x and SiN x H y Masks are formed so that the laser irradiates the material and SiO x 、SiO x N y 、SiN x and SiN x H y The reflected and refracted light waves of the mask are superimposed. As the etching depth increases, this superposition will produce a periodic waveform, making the process signal curve more regular, easier to analyze and judge, and improving the regularity of the process signal curve.

[0029] By obtaining the process signal curve formed by the superposition and interference of light waves generated by the reflection and / or refraction of the laser generated by the EPD during the ICP plasma etching process, the etching depth can be monitored in real time, thereby achieving precise control of the etching process, improving the etching quality and yield, and realizing controllable production.

[0030] This method allows the design of the monitoring area to be adjusted, such as changing the size, shape, spacing, etc. of the exposed area and the covered area to adapt to different material and process requirements, thereby improving the flexibility and adaptability of the detection method. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] In order to more clearly illustrate the specific implementation methods of the present invention or the technical solutions in the prior art, the drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some implementation methods of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0032] Figure 1 This is a schematic diagram of the process in an embodiment of the EPD detection method based on the laser reflection signal during ICP etching of the present application;

[0033] Figure 2 This is a schematic cross-sectional structure diagram of a mask material being arranged on an epitaxial material in an embodiment of an EPD detection method based on a laser reflection signal during ICP etching of the present application;

[0034] Figure 3 This is a schematic diagram of a covering unit in a square rectangle in an embodiment of an EPD detection method based on a laser reflection signal during ICP etching of the present application;

[0035] Figure 4 This is a schematic diagram of a covering unit in an embodiment of an EPD detection method based on a laser reflection signal during ICP etching of the present application, which is a rectangular (long rectangular strip);

[0036] Figure 5 This is a schematic diagram of a circular covering unit in an embodiment of the EPD detection method based on laser reflection signals during ICP etching of the present application;

[0037] Figure 6 This is a process signal curve diagram of Example 1 of the EPD detection method based on the laser reflection signal during ICP etching of this application;

[0038] Figure 7 This is a process signal curve diagram of Example 2 of the EPD detection method based on the laser reflection signal during ICP etching of this application;

[0039] Figure 8 This is a process signal curve diagram of comparative example 1 of the EPD detection method based on laser reflection signal during ICP etching in this application.

[0040] Explanation of the main component symbols: 100-etching monitoring area; 1-epitaxial material; 2-mask material; 21-covering area; 211-covering unit; 3-exposed area. DETAILED DESCRIPTION

[0041] The embodiments of the present invention will be described in detail below in conjunction with the examples, but it will be appreciated by those skilled in the art that the following examples are only used to illustrate the present invention and should not be considered as limiting the scope of the present invention. If no specific conditions are specified in the examples, the conditions are carried out according to normal conditions or the conditions recommended by the manufacturer. If the manufacturer of the reagents or instruments used is not specified, they are all conventional products that can be obtained commercially.

[0042] refer to Figure 1 In an embodiment of the present application, a method for detecting an EPD based on a laser reflection signal during ICP etching is provided, comprising:

[0043] Step S1, disposing a mask material distributedly covering the surface of the epitaxial material on the epitaxial material to form an etching monitoring area in which a covered area based on the mask material and an exposed area not covered by the mask material alternately and periodically exist;

[0044] Step S2, performing ICP plasma etching on the etching monitoring area; and obtaining a light wave signal generated by reflection and / or refraction of laser endpoint monitoring to form a process signal curve;

[0045] Step S3, determining an etching depth of the epitaxial material in the etching monitoring area according to the process signal curve.

[0046] As mentioned above, epitaxial material refers to a thin film material with a single crystal structure formed by epitaxial growth technology on a single crystal substrate. This material maintains the crystal structure and lattice constant of the substrate, but may have a different chemical composition or doping level. Epitaxial growth is a very important technology in materials science and is widely used in semiconductors, optoelectronics and microelectronics.

[0047] As mentioned above, ICP (Inductively Coupled Plasma) etching, i.e. inductively coupled plasma etching, is an advanced dry etching technology widely used in the field of semiconductor manufacturing. It excites the gas through the radio frequency magnetic field generated by the induction coil to form plasma, and uses the ions in the plasma to react physically or chemically with the material to achieve precise etching of micron or nanometer scale patterns. ICP etching technology is favored for its high etching rate, good anisotropy and adaptability to a variety of materials. It can provide precise etching control and is one of the key technologies for achieving fine processing of semiconductor devices.

[0048] As mentioned above, EPD (End Point Detection) detection, or endpoint detection technology, is a detection method for real-time monitoring and control of the etching process. During the ICP etching process, EPD generates a signal graph curve through the interference of the reflected or refracted light generated by the interaction between the incident laser and the material to determine whether the etching depth has reached the predetermined target. This technology can improve the automation and accuracy of the etching process, reduce human intervention, and thus improve production efficiency and the quality and reliability of semiconductor devices. EPD technology is an important tool to ensure the accuracy and consistency of the etching process, and is crucial for the manufacture of high-performance semiconductor devices.

[0049] In step S1, a mask material (such as SiO x and SiO x N y , SiN x , SiN x H y The material is distributed on the surface of the epitaxial material to form an etching monitoring area where distributed covered areas and exposed areas alternate. This means that on the surface of the epitaxial material, part of the epitaxial material is covered by the mask material, while other areas are exposed.

[0050] As mentioned above, distributed coverage, that is, the covered area and the exposed area exist alternately, for example, can be in the form of a matrix of a certain scale, which includes the covered area and the exposed area outside the covered area, forming a monitoring area with a specific pattern, which is composed of mask materials and exposed epitaxial materials alternatingly.

[0051] As described above, by designing the pattern of the monitoring area, the monitoring process of the laser can be controlled more accurately. This design helps to generate a more regular process signal curve, thereby more accurately monitoring the etching depth.

[0052] In step S2, the etching monitoring area formed in step S1 is monitored using the laser emitted by the EPD. At the same time, the light waves generated by the reflection and / or refraction of the laser during the etching process are collected, and these light waves will form a process signal curve. This curve reflects the reflection and refraction characteristics of the material and mask material to the laser during the etching process. By analyzing the process signal curve, the etching depth can be monitored in real time, improving the controllability of the etching process. This method is applicable to a variety of materials, including those that are difficult to monitor in traditional EPD detection methods.

[0053] In step S3, the process signal curve obtained in step S2 is analyzed, and the etching depth of the epitaxial material is determined according to the characteristics of the curve (such as the number and characteristics of the peaks and troughs, etc.). The etching depth of the epitaxial material is determined, and precise control is provided for the etching process. This step improves the etching accuracy and helps to improve the performance and yield rate of semiconductor devices. Through real-time monitoring and adjustment, material waste can be reduced and production efficiency can be improved.

[0054] It should be noted that the detection method provided in the embodiments of the present application can be applied to conventional epitaxial materials. In addition, it can also be applied to materials with complex structures that are dry-etched, such as alternating growth or non-fixed refractive index materials.

[0055] It should be noted that in the semiconductor manufacturing process, precise control of etching depth is crucial. The traditional monitoring method relies on laser irradiation of a single material and judging the etching depth through the process curve generated by reflection, refraction and interference. However, this method has limitations, especially when facing multi-layer materials composed of III-V elements or material structures with no fixed refractive index caused by non-single doping, it cannot produce a regular waveform and thus cannot accurately judge the etching depth.

[0056] In order to overcome this challenge, the above method is proposed in the embodiment of the present application, by setting a distributed area of ​​mask material covering the surface of the epitaxial material in the monitoring area, thereby expanding the use range of the monitoring area. The mask material enables the material to produce stable reflection and refraction light waves under laser irradiation. When the laser is irradiated onto the epitaxial material and the mask material layer at the same time, the reflection and refraction light waves of the two materials will be superimposed. As the etching depth increases, this superposition will produce periodic peaks and troughs, forming a regular waveform diagram, so that the etching depth can be accurately judged.

[0057] In addition, this method is also suitable for etching monitoring of opaque materials. In this case, only the superposition of the reflected light waves on the material surface and the reflected and refracted light waves of the mask material can produce a periodic waveform as the depth of the material increases. This method can significantly improve the monitoring effect.

[0058] In short, by adding the area of ​​mask material to the etching monitoring area, accurate etching depth monitoring can be provided for multi-layer materials that are difficult to process with traditional methods. This method not only improves the accuracy of the etching process, but also expands the application scope of monitoring technology, bringing important technological progress to the field of semiconductor manufacturing.

[0059] Furthermore, the mask material has a uniform structure and a single refractive index.

[0060] As mentioned above, the film material with a uniform structure and a single refractive index is selected as a mask in the EPD detection method to ensure that under laser irradiation, the material can produce a stable and regular light wave reflection and refraction pattern when it works together with the epitaxial material to be etched. This stability and consistency helps to form a clear process signal curve, making the monitoring of etching depth more accurate. In addition, the stability of this film material makes its optical properties less susceptible to environmental changes, thereby improving the reliability of the monitoring signal. It can also expand the scope of application of the monitoring method. Even those materials with complex structures or unstable refractive indices can be assisted by this film material to achieve effective etching process monitoring. The use of this film material simplifies the analysis process of the process curve diagram, reduces the risk of misjudgment, and enhances the flexibility and control accuracy of the entire etching process. Therefore, the introduction of this film material not only solves the limitations of traditional monitoring methods when facing complex materials, but also improves the overall performance and reliability of the etching process.

[0061] Furthermore, the laser light emitted by the etching endpoint monitor EPD configured by the ICP etcher that irradiates the mask material and the epitaxial material at the same time, and the light waves reflected and / or refracted back can be superimposed.

[0062] As mentioned above, by precisely controlling the laser emitted by the EPD to irradiate the mask material and the epitaxial material at the same time, the superposition of the reflected and / or refracted light waves of the two materials can be achieved. The key purpose of this design is to improve the accuracy and reliability of etching depth monitoring. The superposition of light waves generated when the laser interacts with the two materials can form an interference pattern with obvious contrast and regularity, which not only enhances the characteristics of the process curve, making it easier to identify and analyze, but also improves the identifiability of the etching depth. In addition, this superposition effect is particularly effective for monitoring materials with complex structures or non-fixed refractive indices, because it can produce more regular waveforms, so that the etching process of these materials can also be effectively monitored. This method also improves the adaptability of the process, enabling it to adapt to different materials and process conditions, and achieve more precise and reliable etching control.

[0063] Furthermore, the mask material includes SiO x 、SiO x N y 、SiN x and SiN x H y At least one of .

[0064] As mentioned above, SiO x and SiN x These are two materials used in semiconductor manufacturing and in the methods of the present application, where "x" represents the number of oxygen or nitrogen atoms bonded to silicon, which can vary and is used to represent the stoichiometric ratio of these materials. x and SiN x In the figure, x represents the atomic ratio of silicon to oxygen or nitrogen, which can be adjusted according to the manufacturing process and the desired material properties. In practical applications, the value of x is usually precisely controlled through processes such as chemical vapor deposition (CVD) or atomic layer deposition (ALD) to ensure that the material has the desired electrical and optical properties.

[0065] In SiO x In the formula, "x" represents the number of oxygen atoms bonded to silicon, which can be expressed as the ratio of oxygen to silicon atoms. In practice, this ratio can vary and can be limited to between 1 and 2. For example, SiO2 is the most common form, which means that each silicon atom is bonded to two oxygen atoms to form complete silicon dioxide. If "x" is less than 2, such as SiO 1.5 or SiO 1.3 , meaning that the proportion of oxygen is slightly less than that of full silica, this material has different physical and chemical properties.

[0066] In SiN xIn the formula, "x" represents the ratio of nitrogen to silicon atoms. This ratio can also vary, but is usually between 1 and 2. For example, SiN 1.5 This means that each silicon atom is bonded to 1.5 nitrogen atoms, which is a common form of silicon nitride. If "x" is greater than 1, such as SiN2, it means that the nitrogen ratio exceeds the case where each silicon atom is bonded to two nitrogen atoms, and this material may have a higher nitrogen content.

[0067] For example, they can represent silicon dioxide (Silicon Dioxide) and silicon nitride (Silicon Nitride) respectively.

[0068] For further reference, Figure 2 , the mask material, through a plurality of covering units independently covering the surface of the epitaxial material, constitutes the covering area;

[0069] The exposed area not covered by the mask material is arranged between the covering units.

[0070] The covering area includes a plurality of covering units, and hollow exposed areas are arranged between the covering units.

[0071] Furthermore, a plurality of the covering units constitute the covering area of ​​the array structure.

[0072] As mentioned above, in order to make the superposition of such light waves more uniform and the waveform more obvious, in the embodiment of the present application, an array structure in which epitaxial materials and mask materials alternately exist is adopted, that is, an array-type coverage area is formed.

[0073] Furthermore, the spacing between each of the covering units is 1 μm to 20 μm, for example, 1 μm, 3 μm, 5 μm, 7 μm, 9 μm, 10 μm, 15 μm, 20 μm, etc.

[0074] As mentioned above, in the EPD detection method, a larger exposed area helps to provide more information about the etching state of the material, so that the etching process can be more comprehensively monitored and controlled during the etching process. This design also takes into account the monitoring needs of complex material structures. By increasing the proportion of the exposed area, even when facing complex structures such as multi-layer materials or non-single doped materials, a regular waveform can be generated, thereby accurately judging the etching depth.

[0075] In short, by optimizing the area ratio of exposed area to covered area, improving the flexibility and adaptability of etching monitoring, and ensuring accurate etching depth control under various materials and process conditions, the process quality and efficiency in the semiconductor manufacturing process can be improved.

[0076] Furthermore, the shape of the covering unit includes at least one of a rectangle, a diamond, a circle, and an arc.

[0077] The above-mentioned shapes may include rectangles, diamonds, circles, and arcs, among which, for example, they may be squares, rectangles, strips, triangles, semicircles with a certain curvature, and other shapes are also possible.

[0078] For example, the coverage unit is a square (such as Figure 3 ), through a plurality of square covering units, arranged in a regular pattern, forming an array of covering areas, and between each square, there is an exposed area.

[0079] For another example, the covering unit is a long rectangular strip (such as Figure 4 ), multiple covering units are arranged in parallel to form a matrix, and there are exposed areas between the long rectangular strips (strips).

[0080] For another example, the covering unit is circular (such as Figure 5 ), forming a matrix of circular covering units with exposed areas between the covering units.

[0081] Furthermore, the step S1, on the epitaxial material, a mask material is provided which is distributed and covers the surface of the epitaxial material to form an etching monitoring area in which a covered area based on the mask material and an exposed area not covered by the mask material alternately exist, comprises:

[0082] Step S11, defining the etching monitoring area at the corresponding area set on the photomask; wherein the etching monitoring area includes a covered area and an exposed area;

[0083] Step S12, growing the mask material on the surface of the epitaxial material to form a composite sheet source;

[0084] Step S13, photolithography the composite source using the photomask, and then removing the unprotected mask material therein to form the etching monitoring area where the covered area covered by the mask material and the exposed area not covered by the mask material alternately exist.

[0085] As mentioned above, the photomask, also often called a mask, reticle or photolithography mask, is a key component used in the photolithography process. Photolithography is a process used to transfer microscopic patterns on semiconductor wafers, and it plays a central role in the manufacture of microelectronic devices, integrated circuits (ICs) and other micron / nanoscale structures.

[0086] In the method for constructing an etching monitoring area based on alternating covered areas of the mask material and exposed areas not covered by the mask material, a design is first performed through a photolithography plate to determine the specific covered areas and exposed areas therein (for example, in the designed etching monitoring area, the covered area includes a plurality of square covered units, and the exposed area is a mesh structure).

[0087] Then, the surface of the mask material is grown to form the composite source as a whole. Then, on the surface of the composite source, the composite source is photolithographically processed by using a designed photomask, and the mask material (such as silicon dioxide, etc.) not protected by the glue is removed by a dry method or a wet method. At this time, the etching monitoring area left after the glue removal (such as using a glue removal liquid) is an etching monitoring area where the covered area based on the mask material and the exposed area not covered by the mask material alternately exist.

[0088] Embodiment 1:

[0089] In this example, EPD detection was performed.

[0090] Experimental methods:

[0091] S1, delineate the etching monitoring area at the corresponding area set by the photolithography plate; wherein the etching monitoring area includes a covered area and an exposed area; wherein the etching monitoring area is 5mm×5mm; the covering units in the covered area are uniformly arranged 20μm×20μm opaque blocks with a spacing of 20μm, and the exposed area is a mesh structure.

[0092] S2, growing the mask material on the surface of the epitaxial material to form a composite sheet source; the mask material is a SiO2 mask; the thickness is 700 μm.

[0093] S3, using a photomask to photolithography the composite source, then removing the unprotected mask material therein, and removing the glue with a degumming liquid to leave an etching monitoring area such as Figure 3 As shown, covered areas and exposed areas alternate.

[0094] S4, performing ICP plasma etching on the etching monitoring area; and obtaining light waves generated by the EPD laser reflecting and / or refracting the etching monitoring area to form a process signal curve;

[0095] S5, determining an etching depth of the epitaxial material in the etching monitoring area according to the process signal curve.

[0096] Embodiment 2:

[0097] In this embodiment, the method provided in Embodiment 1 is basically adopted, except that opaque blocks (covering units) with a size of 10 μm×10 μm and a spacing of 4 μm are uniformly arranged in the etching monitoring area.

[0098] Comparative Example 1:

[0099] In this comparative example, the method provided in Example 1 is basically adopted, except that the etching monitoring area is a square frame of 1000 μm×1000 μm in size.

[0100] Comparative experimental results:

[0101] refer to Figures 6 to 8 , it can be seen that Figure 6 and Figure 7 They are: the light-proof blocks (covering units) arranged in 20μm×20μm and with a spacing of 20μm in Example 1, and the light-proof blocks (covering units) arranged in 10μm×10μm and with a spacing of 4μm in Example 2 are used as monitoring areas. The curve graph of the signal intensity formed in the process of etching IIIV versus etching time shows that there are obvious and regular waves in the entire etching time period. Therefore, the etching depth can be judged according to the number of waves, and the etching rate can be judged by the size of the waves.

[0102] In contrast, Figure 8 The opening of comparative example 1 is a square hole of 1000μm×1000μm, and the other positions are covered with masks as monitoring areas. It can be clearly seen that no waveform appears for a long time in the middle, and thus it is impossible to determine useful information such as etching depth and etching rate.

[0103] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein by equivalents. However, these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. An EPD detection method based on laser reflection signal during ICP etching, characterized in that: include: On the epitaxial material, a mask material is provided which is distributed and covers the surface of the epitaxial material, so as to form an etching monitoring area where a covered area based on the mask material and an exposed area not covered by the mask material alternately and periodically exist; Performing ICP plasma etching on the etching monitoring area; and, obtaining a light wave signal generated by reflection and / or refraction of the laser endpoint monitoring to form a process signal curve; An etching depth of the epitaxial material in the etching monitoring area is determined according to the process signal curve.

2. The EPD detection method based on the laser reflection signal during ICP etching according to claim 1, characterized in that: The mask material has a uniform structure and a single refractive index.

3. The EPD detection method based on laser reflection signal during ICP etching according to claim 1, characterized in that: The laser light emitted by the etching endpoint monitor EPD configured by the ICP etcher which irradiates the mask material and the epitaxial material at the same time, and the light waves reflected and / or refracted back can be superimposed.

4. The EPD detection method based on laser reflection signal during ICP etching according to claim 1, characterized in that: The mask material includes SiO x 、SiO x N y 、SiN x and SiN x H y At least one of .

5. The EPD detection method based on laser reflection signal during ICP etching according to claim 1, characterized in that: The mask material is formed into the covering area through a plurality of covering units independently covering the surface of the epitaxial material; The exposed area not covered by the mask material is arranged between the covering units.

6. The EPD detection method based on laser reflection signal during ICP etching as claimed in claim 5, characterized in that: A plurality of the covering units constitute the covering area of ​​the array structure.

7. The EPD detection method based on laser reflection signal during ICP etching as claimed in claim 5, characterized in that: The spacing between each of the covering units is 1 μm to 20 μm.

8. The EPD detection method based on laser reflection signal during ICP etching as claimed in claim 5, characterized in that: The shape of the covering unit includes at least one of a rectangle, a diamond, a circle, and an arc.

9. The EPD detection method based on laser reflection signal during ICP etching according to claim 1, characterized in that: The method comprises: disposing a distributed mask material covering the surface of the epitaxial material on the epitaxial material to form an etching monitoring area in which a covered area based on the mask material and an exposed area not covered by the mask material alternately and periodically exist. The method comprises: Delineating the etching monitoring area at the corresponding area set on the photomask; wherein the etching monitoring area includes a covered area and an exposed area; Growing the mask material on the surface of the epitaxial material to form a composite sheet source; The composite source is photolithographically processed using the photomask, and then the unprotected mask material is removed to form the etching monitoring area where the covered area covered by the mask material and the exposed area not covered by the mask material alternately exist.

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