Depth measurement structure and depth measurement method of deep trench isolation structure

Abstract

The invention provides a depth measurement structure and a depth measurement method of a deep trench isolation structure. The depth measurement structure comprises a substrate with a first conductive type; the injection region is provided with a second conduction type and is positioned in the substrate; the deep trench isolation structure extends into the substrate from the surface of the substrate and penetrates through the injection region, the injection region wraps at least part of the side wall of the deep trench isolation structure, and the deep trench isolation structure and the injection region form a PN junction; wherein the deep trench isolation structure comprises a doped layer and an isolation layer located between the doped layer and the injection region, the doped layer extends into the substrate from the surface of the substrate and penetrates through the injection region, the bottom of the doped layer is in contact with the substrate, and the doped layer has the first conduction type. Based on the depth measurement structure and the depth measurement method, the depth of the deep trench isolation structure can be obtained, and the depth of the deep trench isolation structure can be monitored.

Description

Technical Field

[0001] The present application relates to the field of semiconductor technology, and in particular to a depth measurement structure and a depth measurement method for a deep trench isolation structure. Background Art

[0002] In the semiconductor field, a deep trench isolation (DTI) structure is mainly used to achieve effective isolation between devices, wherein the depth of the deep trench isolation structure is an important parameter that affects the reliability of the semiconductor device in which it is located.

[0003] However, the related art can generally only monitor the depth of deep trench isolation structures with a depth not exceeding 20um, and it is difficult to effectively monitor the depth of deep trench isolation structures with a depth greater than 20um. In addition, the depth monitoring requires slicing of the deep trench isolation structure before measurement can be performed, but slicing requires a lot of time and resources.

[0004] Therefore, improvements are needed to at least partially address the above problems. Summary of the invention

[0005] A series of simplified concepts are introduced in the Summary of the Invention section, which will be further described in detail in the Detailed Description of the Invention section. The Summary of the Invention section of this application does not mean to attempt to define the key features and essential technical features of the claimed technical solution, nor does it mean to attempt to determine the scope of protection of the claimed technical solution.

[0006] In view of the existing problems, the present application provides a depth measurement structure of a deep trench isolation structure, including:

[0007] a substrate having a first conductivity type;

[0008] an implantation region of a second conductivity type, located in the substrate;

[0009] A deep trench isolation structure extending from the surface of the substrate into the substrate and penetrating the implantation region, the implantation region covering at least a portion of the sidewall of the deep trench isolation structure, the deep trench isolation structure and the implantation region forming a PN junction;

[0010] The deep trench isolation structure includes a doped layer and an isolation layer located between the doped layer and the injection region, the doped layer extends from the surface of the substrate into the substrate and penetrates the injection region, and the bottom of the doped layer contacts the substrate, and the doped layer has a first conductivity type.

[0011] Exemplarily, the deep trench isolation structure includes a straight line morphology region, a right angle morphology region and an oblique angle morphology region, and each morphology region is correspondingly provided with the implantation region.

[0012] Exemplarily, a shallow trench isolation structure is also included, wherein the shallow trench isolation structure is connected to the deep trench isolation structure and is located on both sides of the top of the deep trench isolation structure, and the shallow trench isolation structure includes an insulating layer.

[0013] Exemplarily, the first conductivity type is P type, and the second conductivity type is N type; or

[0014] The first conductivity type is N type, and the second conductivity type is P type.

[0015] Exemplarily, the material of the doping layer includes doped polysilicon;

[0016] The isolation layer and the insulating layer are made of oxide.

[0017] In another aspect, the present application provides a method for measuring the depth of a deep trench isolation structure, the method comprising:

[0018] Providing a substrate, the substrate comprising a device region and a depth measurement region, the device region is formed with a semiconductor device, and the depth measurement region is formed with the above-mentioned depth measurement structure;

[0019] Obtaining a preset corresponding relationship between the depth of the deep trench isolation structure and the breakdown voltage of a PN junction formed by the deep trench isolation structure and the implantation region;

[0020] Measuring a breakdown voltage of a PN junction formed by the deep trench isolation structure and the implantation region;

[0021] Based on the breakdown voltage and the preset corresponding relationship, the depth of the deep trench isolation structure is obtained.

[0022] Exemplarily, the deep trench isolation structure includes a straight line morphology area, a right angle morphology area and an oblique angle morphology area, and each morphology area is correspondingly provided with the implantation area;

[0023] Measuring the depth of the deep trench isolation structure in the straight line morphology area, the right angle morphology area and the oblique angle morphology area respectively, comprising:

[0024] respectively measuring the breakdown voltages of PN junctions formed by the deep trench isolation structures in the straight-line morphology area, the right-angle morphology area, and the oblique-angle morphology area and the correspondingly arranged injection areas;

[0025] Based on the breakdown voltage and the preset corresponding relationship, the depths of the deep trench isolation structure in the straight line morphology area, the right angle morphology area and the oblique angle morphology area are obtained.

[0026] Exemplarily, measuring the breakdown voltage of a PN junction formed by the deep trench isolation structure and the implantation region includes:

[0027] When the first conductivity type is P type and the second conductivity type is N type, an adjustable first voltage is applied to the doped layer and an adjustable second voltage is applied to the implanted region, respectively, the second voltage is greater than the first voltage, and the second voltage and the first voltage are adjusted until a current appears at the PN junction, at which time the difference between the second voltage and the first voltage is the breakdown voltage;

[0028] When the first conductivity type is N type and the second conductivity type is P type, an adjustable first voltage is applied to the doping layer and an adjustable second voltage is applied to the injection region, respectively, the second voltage is less than the first voltage, and the second voltage and the first voltage are adjusted until current appears at the PN junction, at which time the difference between the first voltage and the second voltage is the breakdown voltage.

[0029] Exemplarily, a preset corresponding relationship between the depth of the deep trench isolation structure and the breakdown voltage of a PN junction formed by the deep trench isolation structure and the implantation region is obtained through simulation.

[0030] Exemplarily, the preset corresponding relationship is a linear regression equation, and the linear fit of the linear regression equation is greater than 0.6.

[0031] The depth measurement structure and depth measurement method of the deep trench isolation structure of the embodiment of the present application are such that the deep trench isolation structure can form a PN junction with the injection region. Based on the preset correspondence between the measured breakdown voltage of the PN junction and the depth of the acquired deep trench isolation structure and the breakdown voltage of the PN junction, the depth of the deep trench isolation structure can be obtained, and the depth of the deep trench isolation structure can be monitored simply and efficiently. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] The following drawings of the present application are used as a part of the present application for understanding the present application. The drawings show the embodiments of the present application and their descriptions, which are used to explain the principle of the present application.

[0033] In the attached figure:

[0034] Figure 1 A partial cross-sectional schematic diagram of a depth measurement structure of a deep trench isolation structure according to a specific embodiment of the present application is shown;

[0035] Figure 2 A schematic top view of a depth measurement structure of a deep trench isolation structure according to a specific embodiment of the present application is shown;

[0036] Figure 3A flow chart of a method for measuring the depth of a deep trench isolation structure according to a specific embodiment of the present application is shown. DETAILED DESCRIPTION

[0037] Next, the present application will be described more completely in conjunction with the accompanying drawings, in which embodiments of the present application are shown. However, the present application can be implemented in different forms and should not be construed as being limited to the embodiments set forth herein. On the contrary, providing these embodiments will make the disclosure thorough and complete, and will fully convey the scope of the present application to those skilled in the art. In the accompanying drawings, for clarity, the sizes and relative sizes of layers and regions may be exaggerated. The same reference numerals throughout represent the same elements.

[0038] It should be understood that when an element or layer is referred to as "on ...", "adjacent to ...", "connected to" or "coupled to" other elements or layers, it can be directly on, adjacent to, connected to or coupled to other elements or layers, or there can be intervening elements or layers. On the contrary, when an element is referred to as "directly on ...", "directly adjacent to ...", "directly connected to" or "directly coupled to" other elements or layers, there are no intervening elements or layers. It should be understood that although the terms first, second, third, etc. can be used to describe various elements, components, regions, layers and / or parts, these elements, components, regions, layers and / or parts should not be limited by these terms. These terms are only used to distinguish one element, component, region, layer or part from another element, component, region, layer or part. Therefore, without departing from the teachings of the present application, the first element, component, region, layer or part discussed below can be represented as a second element, component, region, layer or part.

[0039] Spatially relative terms such as "under," "below," "below," "under," "above," "above," etc., may be used herein for ease of description to describe the relationship of an element or feature shown in the figures to other elements or features. It should be understood that in addition to the orientations shown in the figures, the spatially relative terms are intended to include different orientations of the device in use and operation. For example, if the device in the accompanying drawings is flipped, then the elements or features described as "under other elements" or "under" or "under" will be oriented as "on" the other elements or features. Therefore, the exemplary terms "under" and "under" may include both upper and lower orientations. The device may be oriented otherwise (rotated 90 degrees or other orientations) and the spatial descriptors used herein are interpreted accordingly.

[0040] The purpose of the terms used herein is only to describe specific embodiments and is not intended to be limiting of the present application. When used herein, the singular forms "a", "an", and "said / the" are also intended to include the plural forms, unless the context clearly indicates otherwise. It should also be understood that the terms "consisting of" and / or "comprising", when used in this specification, determine the presence of the features, integers, steps, operations, elements and / or parts, but do not exclude the presence or addition of one or more other features, integers, steps, operations, elements, parts and / or groups. When used herein, the term "and / or" includes any and all combinations of the relevant listed items.

[0041] Embodiments of the application are described herein with reference to cross-sectional views that are schematic diagrams of ideal embodiments (and intermediate structures) of the present application. Thus, variations from the shapes shown due to, for example, manufacturing techniques and / or tolerances can be expected. Therefore, embodiments of the present application should not be limited to the specific shapes of the zones shown herein, but include shape deviations due to, for example, manufacturing. For example, an implanted region shown as a rectangle typically has rounded or curved features and / or an implant concentration gradient at its edges, rather than a binary change from an implanted region to a non-implanted region. Similarly, a buried region formed by implantation may result in some implantation in the region between the buried region and the surface through which the implantation is performed. Therefore, the regions shown in the figures are schematic in nature, and their shapes are not intended to show the actual shape of the region of the device and are not intended to limit the scope of the present application.

[0042] Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by ordinary technicians in the field of this application. It will also be understood that terms such as those defined in commonly used dictionaries should be understood to have a meaning consistent with their meaning in the context of the relevant art and / or this specification, and should not be interpreted in an ideal or overly formal sense unless expressly defined as such herein.

[0043] In order to thoroughly understand the present application, detailed steps and structures will be presented in the following description to illustrate the technical solution proposed by the present application. The preferred embodiments of the present application are described in detail below, but in addition to these detailed descriptions, the present application may also have other implementations.

[0044] In the related art, in order to monitor the depth of a deep trench isolation structure having a depth greater than 20 um, it is generally necessary to add an additional measurement machine or to slice the deep trench isolation structure to monitor the depth of the deep trench isolation structure having a depth greater than 20 um.

[0045] However, adding additional measurement equipment will increase costs, and slicing the deep trench isolation structure will take a lot of time and resources. The above solutions cannot simply and efficiently monitor the depth of the deep trench isolation structure with a depth greater than 20um.

[0046] Therefore, in view of the existence of the above-mentioned technical problems, the embodiment of the present application proposes a depth measurement structure and a depth measurement method of a deep trench isolation structure, the depth measurement structure comprising: a substrate having a first conductivity type; an implantation region having a second conductivity type, located in the substrate; a deep trench isolation structure, extending from the surface of the substrate into the substrate and penetrating the implantation region, the implantation region covering at least part of the sidewall of the deep trench isolation structure, the deep trench isolation structure and the implantation region forming a PN junction; wherein the deep trench isolation structure comprises a doping layer and an isolation layer located between the doping layer and the implantation region, the doping layer extending from the surface of the substrate into the substrate and penetrating the implantation region, and the bottom of the doping layer contacts the substrate, and the doping layer has the first conductivity type. The depth measurement method based on the above-mentioned depth measurement structure comprises: providing a substrate, the substrate comprising a device region and a depth measurement region, the device region is formed with a semiconductor device, and the depth measurement region is formed with the above-mentioned depth measurement structure; obtaining a preset corresponding relationship between the depth of the deep trench isolation structure and the breakdown voltage of the PN junction formed by the deep trench isolation structure and the implantation region; measuring the breakdown voltage of the PN junction formed by the deep trench isolation structure and the implantation region; and obtaining the depth of the deep trench isolation structure based on the breakdown voltage and the preset corresponding relationship.

[0047] The depth measurement structure and depth measurement method of the deep trench isolation structure of the embodiment of the present application, the deep trench isolation structure can form a PN junction with the injection region, based on the preset correspondence between the measured breakdown voltage of the PN junction and the obtained depth of the deep trench isolation structure and the breakdown voltage of the PN junction, the depth of the deep trench isolation structure can be obtained, the depth of the deep trench isolation structure can be monitored simply and efficiently, and there is no need for slicing, which shortens the measurement time and reduces the measurement cost.

[0048] Embodiment 1

[0049] Below, reference Figure 1 and Figure 2 The depth measurement structure of the deep trench isolation structure of the present application is described in detail, wherein: Figure 1 A partial cross-sectional schematic diagram of a depth measurement structure of a deep trench isolation structure according to a specific embodiment of the present application is shown. Figure 2 FIG. 1 is a top view schematic diagram of a depth measurement structure of a deep trench isolation structure according to a specific embodiment of the present application. Figure 1 and Figure 2 As shown, the depth measurement structure of the deep trench isolation structure of the embodiment of the present application includes:

[0050] A substrate 100 having a first conductivity type;

[0051] An implantation region 110 having a second conductivity type, located in the substrate 100;

[0052] A deep trench isolation structure 120 extends from the surface of the substrate 100 into the substrate 100 and penetrates the implantation region 110. The implantation region 110 covers at least a portion of the sidewall of the deep trench isolation structure 120. The deep trench isolation structure 120 and the implantation region 110 form a PN junction.

[0053] Among them, the deep trench isolation structure 120 includes a doping layer 121 and an isolation layer 122 located between the doping layer 121 and the injection region 110, the doping layer 121 extends from the surface of the substrate 100 to the substrate 100 and penetrates the injection region 110, and the bottom of the doping layer 121 contacts the substrate 100, and the doping layer 121 has a first conductivity type.

[0054] In one example, the first conductivity type is P type, and the second conductivity type is N type; or, the first conductivity type is N type, and the second conductivity type is P type.

[0055] In one example, the substrate 100 is a bulk silicon substrate, which can be at least one of the following materials: Si, Ge, SiGe, SiC, SiGeC, InAs, GaAs, InP, InGaAs or other III / V compound semiconductors, including multilayer structures composed of these semiconductors, or silicon on insulator (SOI), stacked silicon on insulator (SSOI), stacked silicon germanium on insulator (S-SiGeOI), silicon germanium on insulator (SiGeOI) and germanium on insulator (GeOI). Although several examples of materials that can form the substrate 100 are described herein, any material that can be used as a substrate falls within the spirit and scope of the present application.

[0056] In one example, if Figure 1 and Figure 2 As shown, a shallow trench isolation (STI) structure 130 is also included. The shallow trench isolation structure 130 is connected to the deep trench isolation structure 120 and is located on both sides of the deep trench isolation structure 120. The shallow trench isolation structure 130 includes an insulating layer 131.

[0057] In one example, the material of the doping layer 121 includes doped polysilicon, or may be any other suitable material doped with ions of the first conductive type, which is not limited in the present application.

[0058] In one example, the material of the isolation layer 122 and the insulating layer 131 includes oxide, such as silicon oxide, or the isolation layer 122 and the insulating layer 131 can also be any other suitable insulating material, which is not limited in the present application. Exemplarily, the isolation layer 122 and the insulating layer 131 have suitable materials. Exemplarily, the isolation layer 122 is also located between the doped layer 121 and the insulating layer 131.

[0059] In one example, if Figure 2 As shown, the deep trench isolation structure 120 includes a straight line morphology area, a right angle morphology area and an oblique angle morphology area, and each morphology area is correspondingly provided with an injection area 110. The present application can monitor the depth of the deep trench isolation structure 120 in the straight line morphology area, the right angle morphology area and the oblique angle morphology area respectively, which will be described in detail in the depth measurement method part below.

[0060] In one example, if Figure 2 As shown, in the top view, the deep trench isolation structure 120 is a ring structure, and the shallow trench isolation structure 130 is located at the inner and outer sides of the top of the deep trench isolation structure 120 respectively, and the shallow trench isolation structure 130 and the deep trench isolation structure 120 jointly play the role of electrical isolation.

[0061] In one example, the doping layer 121 and the substrate 100 both have a first conductivity type, the injection region 110 has a second conductivity type, and the doping layer 121 penetrates the injection region 110 and the bottom of the doping layer 121 contacts the substrate 100, so that the doping layer 121 and the substrate 100 as a whole can serve as the P-type part in the PN junction, and the injection region 110 can serve as the N-type part in the PN junction, so that the doping layer 121 and the substrate 100 as a whole can form a PN junction with the injection region 110, that is, the deep trench isolation structure 120 can form a PN junction with the injection region 110. The inventors of the present application have discovered that a preset corresponding relationship can be established between the depth of the deep trench isolation structure 120 and the breakdown voltage of the PN junction formed by the deep trench isolation structure 120 and the injection region 110, so that the breakdown voltage of the PN junction formed by the deep trench isolation structure 120 and the injection region 110 can be measured based on the depth measurement structure of the deep trench isolation structure of the present application, and a preset corresponding relationship can be established between the obtained depth of the deep trench isolation structure 120 and the breakdown voltage of the PN junction formed by the deep trench isolation structure 120 and the injection region 110, so that the depth of the deep trench isolation structure 120 can be simply and efficiently obtained, and the depth of the deep trench isolation structure 120 can be monitored without adding additional measuring equipment or slicing processing, thereby reducing costs and saving time and resources.

[0062] In one example, the following steps can be used to form Figure 1 and Figure 2Depth measurement structure of the deep trench isolation structure shown:

[0063] First, a substrate 100 having a first conductivity type is provided, and an implantation region 110 having a second conductivity type is formed in the substrate 100. Specifically, the substrate 100 and the implantation region 110 may be formed by one or more epitaxial growth and ion implantation processes. For example, when the depth of the implantation region 110 is too deep to be formed by one ion implantation process, a partial thickness of the substrate 100 may be epitaxially grown first, and then an ion implantation process may be performed to form a partial implantation region 110, and then epitaxial growth and ion implantation processes may be performed alternately to form an implantation region 110 having a certain depth in the substrate 100. Exemplarily, the implantation region 110 may extend from the surface of the substrate 100 into the substrate 100, or the substrate 100 may also be located in the substrate 100 and have a certain distance from the surface of the substrate 100.

[0064] Next, a deep trench isolation structure 120 is formed. Specifically, the deep trench isolation structure 120 can be formed by the following steps: first, a portion of the substrate 100 and a portion of the implantation region 110 are etched from the surface of the substrate 100 to form a trench, wherein the trench penetrates the implantation region 110 and the implantation region 110 covers at least a portion of the sidewall of the trench. In this step, a commonly used etching process in the art can be used to etch a portion of the substrate 100 and a portion of the implantation region 110 to form a trench, such as a dry etching process. Next, an isolation layer 122 and a doping layer 121 are sequentially formed in the trench to obtain the deep trench isolation structure 120, wherein the isolation layer 122 covers the sidewall of the trench, the doping layer 121 fills the remaining trench and the bottom of the doping layer 121 contacts the substrate 100. In this step, a commonly used deposition method in the art can be used to form the isolation layer 122 and the doping layer 121, such as chemical vapor deposition (CVD), physical vapor deposition (PVD) or atomic layer deposition (ALD), which is not limited in the present application. Exemplarily, when a shallow trench isolation structure 130 is also included, the shallow trench isolation structure 130 and the deep trench isolation structure 120 can be prepared simultaneously. For example, a trench for accommodating the shallow trench isolation structure 130 and the deep trench isolation structure 120 can be formed by an etching process first, and then an insulating layer 131, an isolation layer 122 and a doping layer 121 are formed in the trench to obtain the shallow trench isolation structure 130 and the deep trench isolation structure 120. When the insulating layer 131 and the isolation layer 122 have the same material, such as silicon oxide, silicon oxide can be deposited in the trench to simultaneously form the insulating layer 131 and the isolation layer 122.

[0065] The introduction to the depth measurement structure of the deep trench isolation structure of the embodiment of the present application has been completed. The complete structure may also include other components, which will not be described one by one here.

[0066] According to the depth measurement structure of the deep trench isolation structure of the embodiment of the present application, the deep trench isolation structure can form a PN junction with the injection region. Based on the preset correspondence between the measured breakdown voltage of the PN junction and the obtained depth of the deep trench isolation structure and the breakdown voltage of the PN junction, the depth of the deep trench isolation structure can be obtained, and the depth of the deep trench isolation structure can be monitored simply and efficiently without slicing, thereby shortening the measurement time and reducing the measurement cost.

[0067] Embodiment 2

[0068] The present application also provides a method for measuring the depth of a deep trench isolation structure. The method for measuring the depth of a deep trench isolation structure can be performed based on the depth measurement structure in the first embodiment. Figure 3 As shown, the depth measurement method of the deep trench isolation structure of the embodiment of the present application includes the following steps:

[0069] First, step S1 is performed to provide a substrate, wherein the substrate includes a device region and a depth measurement region. A semiconductor device is formed in the device region, and a depth measurement structure as described in the first embodiment is formed in the depth measurement region.

[0070] In one example, a semiconductor device and a depth measurement structure are formed on the same substrate, and a deep trench isolation structure in a depth measurement region is also formed in the semiconductor device. Based on the depth measurement structure and the depth measurement method of the deep trench isolation structure of the present application, the depth of the deep trench isolation structure can be measured, thereby improving the reliability of the semiconductor device. Exemplarily, in combination with the measured depth of the deep trench isolation structure and the performance test results of the semiconductor device, the depth range of the deep trench isolation structure allowed by the semiconductor device can be adaptively adjusted. For example, assuming that the range of the deep trench isolation structure allowed by the semiconductor device under the premise of ensuring performance is 22um-23um, the depth of the deep trench isolation structure measured at this time is 23.3um and the performance test results of the semiconductor device at this time show that the performance of the semiconductor device is normal, the range of the deep trench isolation structure allowed by the semiconductor device can be adjusted to 22um-23.3um.

[0071] Next, step S2 is performed to obtain a preset corresponding relationship between the depth of the deep trench isolation structure and the breakdown voltage of a PN junction formed by the deep trench isolation structure and the implantation region.

[0072] In one example, a preset corresponding relationship between the depth of the deep trench isolation structure and the breakdown voltage of the PN junction formed by the deep trench isolation structure and the implanted region can be obtained through simulation. For example, the depths of multiple deep trench isolation structures can be set through simulation, and the breakdown voltages of the PN junctions formed by the deep trench isolation structure and the implanted region corresponding to the depths of different deep trench isolation structures can be obtained through simulation, and the preset corresponding relationship between the depth of the deep trench structure obtained through simulation and the breakdown voltage can be obtained.

[0073] In one example, the preset corresponding relationship is a linear regression equation, wherein the linear fit of the linear regression equation is greater than 0.6. Exemplarily, the closer the linear fit is to 1, the higher the accuracy of the linear regression equation. The accuracy of the linear regression equation with a linear fit greater than 0.6 is high enough, so that the accuracy of the depth of the deep trench isolation structure calculated based on the linear regression equation and the measured breakdown voltage of the PN junction formed by the deep trench isolation structure and the injection region meets the requirements. Exemplarily, taking the depths of the deep trench isolation structure set by the simulation as 20um, 26um and 29um, respectively, and the breakdown voltages of the PN junctions corresponding to different depths obtained by simulation as 91.1V, 112.4V, and 116.9V, respectively, as an example, the depth of the deep trench isolation structure is set as x and the breakdown voltage of the PN junction is set as y, then the linear regression equation of the two can be obtained as:

[0074] y=2.9643x+32.693

[0075] The linear fit of the above linear regression equation is 0.9716. Exemplarily, the preset corresponding relationship can also be any other suitable relationship, which is not limited in the present application.

[0076] Next, step S3 is performed to measure the breakdown voltage of the PN junction formed by the deep trench isolation structure and the injection area. Specifically, the breakdown voltage of the PN junction formed by the deep trench isolation structure and the injection area is measured, including: when the first conductivity type is P type and the second conductivity type is N type, an adjustable first voltage is applied to the doped layer and an adjustable second voltage is applied to the injection area, the second voltage is greater than the first voltage, the PN junction is reverse biased, and the second voltage and the first voltage are adjusted until a current appears at the PN junction, and the difference between the second voltage and the first voltage is the breakdown voltage of the PN junction; when the first conductivity type is N type and the second conductivity type is P type, an adjustable first voltage is applied to the doped layer and an adjustable second voltage is applied to the injection area, the second voltage is less than the first voltage, the PN junction is reverse biased, and the second voltage and the first voltage are adjusted until a current appears at the PN junction, and the difference between the first voltage and the second voltage is the breakdown voltage of the PN junction. Exemplarily, in the above steps, only the first voltage can be adjusted, or only the second voltage can be adjusted, or the first voltage and the second voltage can be adjusted simultaneously.

[0077] Finally, step S4 is performed to obtain the depth of the deep trench isolation structure based on the breakdown voltage of the PN junction and the preset corresponding relationship.

[0078] In one example, if Figure 2As shown, the deep trench isolation structure 120 includes a straight line morphology area, a right angle morphology area and an oblique angle morphology area, and each morphology area is correspondingly provided with an implantation area 110. The depths of the deep trench isolation structures in the straight line morphology area, the right angle morphology area and the oblique angle morphology area are measured respectively, including: respectively measuring the breakdown voltage of the PN junction formed by the deep trench isolation structures in the straight line morphology area, the right angle morphology area and the oblique angle morphology area and the corresponding implantation area; based on the breakdown voltage and the preset corresponding relationship, the depths of the deep trench isolation structures in the straight line morphology area, the right angle morphology area and the oblique angle morphology area are obtained. Exemplarily, when the deep trench isolation structure 120 includes a straight morphology area, a right-angle morphology area, and an oblique-angle morphology area, the preset corresponding relationship between the depth of the deep trench isolation structure 120 in the straight morphology area and the breakdown voltage of the PN junction formed by the deep trench isolation structure 120 in the straight morphology area and the corresponding injection area 110, the preset corresponding relationship between the depth of the deep trench isolation structure 120 in the right-angle morphology area and the breakdown voltage of the PN junction formed by the deep trench isolation structure 120 in the right-angle morphology area and the corresponding injection area 110, and the preset corresponding relationship between the depth of the deep trench isolation structure 120 in the oblique-angle morphology area and the breakdown voltage of the PN junction formed by the deep trench isolation structure 120 in the oblique-angle morphology area and the corresponding injection area 110 can be obtained respectively, and subsequently based on the deep trench isolation structure 120 in the morphology area, the preset corresponding relationship between the breakdown voltage of the PN junction formed by the deep trench isolation structure 120 in the right-angle morphology area and the corresponding injection area 110 can be obtained. The depth of the deep trench isolation structure 120 in the morphology area can be obtained based on the preset corresponding relationship between the breakdown voltage of the PN junction formed by the deep trench isolation structure 120 in the morphology area and the corresponding injection area 110, and the measured breakdown voltage of the PN junction formed by the deep trench isolation structure 120 in the morphology area and the corresponding injection area 110; for example, the depth of the deep trench isolation structure 120 in the straight morphology area can be obtained based on the preset corresponding relationship between the depth of the deep trench isolation structure 120 in the straight morphology area and the breakdown voltage of the PN junction formed by the deep trench isolation structure 120 in the straight morphology area and the corresponding injection area 110, and the measured breakdown voltage of the PN junction formed by the deep trench isolation structure 120 in the straight morphology area and the corresponding injection area 110. In other embodiments, a unified preset corresponding relationship can also be established for the depth of the deep trench isolation structure 120 in different morphology areas and the breakdown voltage of the PN junction formed by the deep trench isolation structure 120 and the corresponding injection area 110. In some embodiments of the present application, the depths of the deep trench isolation structure 120 at different morphological positions are obtained by measuring the above-mentioned morphological areas respectively, so that the user can consider and evaluate the overall depth of the deep trench isolation structure, which is beneficial for the user to improve the formation process of the deep trench isolation structure according to the depth distribution of the deep trench isolation structure at different morphological positions and improve the uniformity of the depth of the deep trench isolation structure at each morphological position.

[0079] In an example, taking the first conductivity type as P type and the second conductivity type as N type as an example, Figure 2As shown, measuring the breakdown voltage of the PN junction formed by the deep trench isolation structure 120 in the straight morphology area and the corresponding injection area 110 includes: connecting the doping layer 121 in the deep trench isolation structure 120 to the first connection port 141, and connecting the injection area 110 corresponding to the deep trench isolation structure 120 in the straight morphology area to the second connection port 142; an external device applies a first voltage to the doping layer through the first connection port 141, and applies a second voltage to the injection area 110 through the second connection port 142, the second voltage is greater than the first voltage, so that the PN junction is reverse biased, and the first voltage and the second voltage are adjusted until the external device measures that the PN junction has a current, and at this time, the difference between the second voltage and the first voltage is the breakdown voltage of the PN junction formed by the deep trench isolation structure 120 in the straight morphology area and the corresponding injection area 110. Exemplarily, the external device can measure the current of the PN junction through the first connection port 141 and the second connection port 142, or the external device can measure the current of the PN through an additional connection port.

[0080] In an example, taking the first conductivity type as P type and the second conductivity type as N type as an example, Figure 2 As shown, measuring the breakdown voltage of the PN junction formed by the deep trench isolation structure 120 in the right-angle morphology area and the corresponding injection area 110 includes: connecting the doping layer 121 in the deep trench isolation structure 120 to the first connection port 141, and connecting the injection area 110 corresponding to the deep trench isolation structure 120 in the right-angle morphology area to the third connection port 143; an external device applies a first voltage to the doping layer through the first connection port 141, and applies a second voltage to the injection area 110 through the third connection port 143, the second voltage is greater than the first voltage, so that the PN junction is reverse biased, and the first voltage and the second voltage are adjusted until the external device measures that the PN junction has a current, and at this time, the difference between the second voltage and the first voltage is the breakdown voltage of the PN junction formed by the deep trench isolation structure 120 in the right-angle morphology area and the corresponding injection area 110. Exemplarily, the external device can measure the current of the PN junction through the first connection port 141 and the third connection port 143, or the external device can measure the current of the PN through an additional connection port.

[0081] In an example, taking the first conductivity type as P type and the second conductivity type as N type as an example, Figure 2As shown, measuring the breakdown voltage of the PN junction formed by the deep trench isolation structure 120 in the bevel morphology area and the corresponding implantation area 110 includes: connecting the doping layer 121 in the deep trench isolation structure 120 to the first connection port 141, and connecting the implantation area 110 corresponding to the deep trench isolation structure 120 in the bevel morphology area to the fourth connection port 144; an external device applies a first voltage to the doping layer through the first connection port 141, and applies a second voltage to the implantation area 110 through the fourth connection port 144, the second voltage is greater than the first voltage, so that the PN junction is reverse biased, and the first voltage and the second voltage are adjusted until the external device measures that the PN junction has a current, and at this time, the difference between the second voltage and the first voltage is the breakdown voltage of the PN junction formed by the deep trench isolation structure 120 in the bevel morphology area and the corresponding implantation area 110. Exemplarily, the external device can measure the current of the PN junction through the first connection port 141 and the fourth connection port 144, or the external device can measure the current of the PN through an additional connection port.

[0082] It is worth mentioning that the above steps are only examples, and the order of the above steps can be adjusted without conflict.

[0083] The key steps of the depth measurement method of the deep trench isolation structure of the present application have been described so far. The complete depth measurement method of the deep trench isolation structure may also include other steps, which will not be described one by one here.

[0084] In summary, the depth measurement method of the deep trench isolation structure of the embodiment of the present application measures the depth of the deep trench isolation structure based on the depth measurement structure. The deep trench isolation structure can form a PN junction with the injection region. Based on the preset correspondence between the measured breakdown voltage of the PN junction and the obtained depth of the deep trench isolation structure and the breakdown voltage of the PN junction, the depth of the deep trench isolation structure can be obtained. The depth of the deep trench isolation structure can be monitored simply and efficiently without slicing, thereby shortening the measurement time and reducing the measurement cost.

[0085] Although multiple embodiments are described herein, it should be understood that a variety of other modifications and embodiments may be conceived by those skilled in the art, all of which will fall within the spirit and scope of the concepts disclosed herein. More particularly, various modifications and changes may be made to the arrangements and / or components of the combined arrangements of the subject matter within the scope of the disclosure, drawings, and appended claims of the present application. In addition to modifications and changes to the components and / or arrangements, the use of alternatives is also an obvious option for those skilled in the art.

Claims

1. A depth measurement structure of a deep trench isolation structure, characterized in that: include: a substrate having a first conductivity type; an implantation region of a second conductivity type, located in the substrate; A deep trench isolation structure extending from the surface of the substrate into the substrate and penetrating the implantation region, the implantation region covering at least a portion of the sidewall of the deep trench isolation structure, the deep trench isolation structure and the implantation region forming a PN junction; The deep trench isolation structure includes a doped layer and an isolation layer located between the doped layer and the injection region, the doped layer extends from the surface of the substrate into the substrate and penetrates the injection region, and the bottom of the doped layer contacts the substrate, and the doped layer has a first conductivity type.

2. The depth measurement structure according to claim 1, characterized in that: The deep trench isolation structure comprises a straight line morphology area, a right angle morphology area and an oblique angle morphology area, and each morphology area is correspondingly provided with the implantation area.

3. The depth measurement structure according to claim 1, characterized in that: It also includes a shallow trench isolation structure, which is connected to the deep trench isolation structure and is located on both sides of the top of the deep trench isolation structure. The shallow trench isolation structure includes an insulating layer.

4. The depth measurement structure according to claim 1, characterized in that: The first conductivity type is P type, and the second conductivity type is N type; or The first conductivity type is N type, and the second conductivity type is P type.

5. The depth measurement structure according to claim 3, characterized in that: The material of the doping layer includes doped polysilicon; The isolation layer and the insulating layer are made of oxide.

6. A method for measuring the depth of a deep trench isolation structure, characterized in that: The method comprises: Providing a substrate, the substrate comprising a device region and a depth measurement region, the device region being formed with a semiconductor device, the depth measurement region being formed with a depth measurement structure as claimed in any one of claims 1 to 5; Obtaining a preset corresponding relationship between the depth of the deep trench isolation structure and the breakdown voltage of a PN junction formed by the deep trench isolation structure and the implantation region; Measuring a breakdown voltage of a PN junction formed by the deep trench isolation structure and the implantation region; Based on the breakdown voltage and the preset corresponding relationship, the depth of the deep trench isolation structure is obtained.

7. The depth measurement method according to claim 6, characterized in that: The deep trench isolation structure includes a straight line morphology area, a right angle morphology area and an oblique angle morphology area, and each morphology area is correspondingly provided with the implantation area; Measuring the depth of the deep trench isolation structure in the straight line morphology area, the right angle morphology area and the oblique angle morphology area respectively, comprising: respectively measuring the breakdown voltages of PN junctions formed by the deep trench isolation structures in the straight-line morphology area, the right-angle morphology area, and the oblique-angle morphology area and the correspondingly arranged injection areas; Based on the breakdown voltage and the preset corresponding relationship, the depths of the deep trench isolation structure in the straight line morphology area, the right angle morphology area and the oblique angle morphology area are obtained.

8. The depth measurement method according to claim 6 or 7, characterized in that: Measuring a breakdown voltage of a PN junction formed by the deep trench isolation structure and the implantation region, comprising: When the first conductivity type is P type and the second conductivity type is N type, an adjustable first voltage is applied to the doped layer and an adjustable second voltage is applied to the implanted region, respectively, the second voltage is greater than the first voltage, and the second voltage and the first voltage are adjusted until a current appears at the PN junction, at which time the difference between the second voltage and the first voltage is the breakdown voltage; When the first conductivity type is N type and the second conductivity type is P type, an adjustable first voltage is applied to the doping layer and an adjustable second voltage is applied to the injection region, respectively, the second voltage is less than the first voltage, and the second voltage and the first voltage are adjusted until current appears at the PN junction, at which time the difference between the first voltage and the second voltage is the breakdown voltage.

9. The depth measurement method according to claim 6, characterized in that: The preset corresponding relationship between the depth of the deep trench isolation structure and the breakdown voltage of the PN junction formed by the deep trench isolation structure and the implantation region is obtained through simulation.

10. The depth measurement method according to claim 6, characterized in that: The preset corresponding relationship is a linear regression equation, and the linear fitting degree of the linear regression equation is greater than 0.6.

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