Silicon carbide device, preparation method and new energy equipment

Abstract

The invention provides a silicon carbide device, a preparation method and new energy equipment, and can be widely applied to the technical field of new energy, the silicon carbide device comprises a silicon carbide body, and the surface of the silicon carbide body is provided with a plurality of tube core areas; each tube core area is provided with a plurality of vertex angles; the scribing channel is formed in the area outside the multiple tube core areas, and the area, making contact with the vertex angles of the tube core areas, of the scribing channel is in an arc shape; the scribe lane includes a first trench disposed around the die region to form a protective coating by depositing a dense material in the first trench. According to the invention, the contact part between the scribing channel and the vertex angle of the die region is arc-shaped, so that the stress concentration at the corner of the scribing channel can be reduced, the problem that cracks are easy to generate at the corner of the scribing channel in the related technology can be relieved, the manufacturing yield of the silicon carbide device can be improved, and the electrical performance parameters of silicon carbide can be improved.

Description

Technical Field

[0001] This application relates to the field of new energy technology, and more specifically, to a silicon carbide device, its preparation method, and new energy equipment. Background Technology

[0002] Silicon-based IGBTs dominate high-voltage, high-current applications, but they cannot withstand high-frequency operation and have high power consumption. SiC, on the other hand, with its high voltage and high temperature resistance, allows it to achieve the same voltage withstand capability as silicon-based IGBTs using simpler MOSFET devices, while avoiding their high energy consumption. Under the same conditions, silicon carbide MOSFETs reduce energy loss by 66% compared to silicon-based IGBTs of the same specifications, primarily due to a significant reduction in switching losses. In the new energy vehicle industry, SiC can be used in inverters for driving and controlling motors, on-board chargers, and fast-charging stations. In photovoltaic power generation, leading photovoltaic inverter companies have already adopted SiC power devices to replace silicon devices.

[0003] In related technologies, stress concentration occurs at the corners of the dicing track in SiC devices, which can easily lead to cracks. As a result, the cracked parts of the dicing track are more susceptible to contamination and damage during the dicing process, affecting the electrical performance parameters of the wafer. Summary of the Invention

[0004] The main objective of this application is to provide a silicon carbide device, a fabrication method, and a new energy device, so as to at least solve the problem of easy cracking in the dicing area in the prior art.

[0005] To achieve the above objectives, according to one aspect of this application, a silicon carbide device is provided, comprising: a silicon carbide body, the surface of which is provided with: a plurality of die regions; each die region having a plurality of apex corners; a scribe line, the scribe line being formed in a region outside the plurality of die regions, the area of ​​the scribe line contacting the apex corner of the die region being arc-shaped; the scribe line including a first trench surrounding the die region for forming a protective coating by depositing a dense material in the first trench. This application, by setting the contact point between the scribe line and the apex corner of the die region to arc shape, helps reduce stress concentration at the corners of the scribe line, alleviates the problem of cracks easily forming at the corners of the scribe line in related technologies, and improves the manufacturing yield of silicon carbide devices and enhances the electrical performance parameters of silicon carbide.

[0006] Optionally, the dicing channel includes multiple dicing channels, each dicing channel being formed by a gap between two adjacent core regions, the minimum width of the dicing channel being in the range of 80 to 100 μm, and the arc shape including a circular arc shape with a radius of 5 to 20 μm.

[0007] Optionally, the depth of the first trench is 0.5 to 1.5 μm, and the aspect ratio of the first trench is 1:1 to 5:1.

[0008] Optionally, the slicing channel includes a second groove disposed around the first groove to form a healing agent layer by applying a healing agent material;

[0009] The second trench is 0.2 to 0.5 μm deeper than the first trench, and the width of the second trench is wider than the width of the first trench.

[0010] Optionally, the width of the second trench is 1 to 15 μm.

[0011] To achieve the above objectives, according to another aspect of this application, a method for fabricating a silicon carbide device is provided, the method comprising:

[0012] A wafer is provided; wherein the wafer includes a plurality of die regions;

[0013] A scribe line is formed on the wafer surface outside the die region by means of a preset pattern; wherein the area where the scribe line contacts the apex corner of the die region is arc-shaped;

[0014] A first etching is performed on the dicing channel around the core region to form a first trench; a dense material is deposited in the first trench to form a protective coating.

[0015] Optionally, the method further includes:

[0016] A second etching is performed on the dicing channel at the point where it contacts the first groove to form a second groove; wherein the width of the second groove is wider than the width of the first groove;

[0017] A healing agent material is applied to the second groove to form a healing agent layer.

[0018] Optionally, the method further includes:

[0019] The depth of the first trench is determined to be 0.5 to 1.5 μm;

[0020] The depth of the second trench is determined to be 0.2 to 0.5 μm deeper than the depth of the first trench.

[0021] Optionally, the method further includes:

[0022] The surface of the silicon carbide device is thinned and a back-side processing is performed to form the silicon carbide device.

[0023] According to another aspect of this application, a new energy device is provided, which is driven by the aforementioned silicon carbide device.

[0024] By applying the technical solution of this application, by setting the contact point between the dicing track and the die area to an arc shape, it is beneficial to reduce stress concentration at the corner of the dicing track, alleviate the problem of cracks easily generated at the corner of the dicing track in related technologies, and improve the manufacturing yield of silicon carbide devices and improve the electrical performance parameters of silicon carbide. Attached Figure Description

[0025] The accompanying drawings, which form part of this application, are used to provide a further understanding of this application. The illustrative embodiments and descriptions of this application are used to explain this application and do not constitute an undue limitation of this application. In the drawings:

[0026] Figure 1 A top view of the structure of a silicon carbide device according to an embodiment of the related technology;

[0027] Figure 2 A top view of the structure of a silicon carbide device provided in an embodiment of this application is shown;

[0028] Figure 3 A schematic flowchart illustrating a method for fabricating a silicon carbide device according to an embodiment of the related technology;

[0029] Figure 4 A schematic flowchart of a method for fabricating a silicon carbide device according to an embodiment of this application is shown;

[0030] Figure 5 A schematic diagram of the structure of a first etched silicon carbide device according to an embodiment of this application is shown;

[0031] Figure 6 A schematic diagram of the structure of a silicon carbide device after first trench filling according to an embodiment of this application is shown;

[0032] Figure 7 A schematic diagram of the structure of a second etched silicon carbide device according to an embodiment of this application is shown;

[0033] Figure 8 A schematic diagram of the structure of a second trench-filled silicon carbide device according to an embodiment of this application is shown;

[0034] The above figures include the following reference numerals:

[0035] 11, die area; 12, scribe line; 13, protective coating area; 14, healing agent area; 131, first trench; 132, protective coating; 141, second trench; 142, healing agent layer; 21, drift area; 22, silicon carbide substrate. Detailed Implementation

[0036] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other. This application will now be described in detail with reference to the accompanying drawings and embodiments.

[0037] To enable those skilled in the art to better understand the present application, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present application, and not all embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative effort should fall within the scope of protection of the present application.

[0038] It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this application are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate for the embodiments of this application described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0039] As described in the background section, in related technologies:

[0040] Silicon-based IGBTs dominate high-voltage, high-current applications, but they cannot withstand high-frequency operation and have high power consumption. SiC, on the other hand, with its high voltage and high temperature resistance, allows it to achieve the same voltage withstand capability as silicon-based IGBTs using simpler MOSFET devices, while avoiding their high energy consumption. Under the same conditions, silicon carbide MOSFETs reduce energy loss by 66% compared to silicon-based IGBTs of the same specifications, primarily due to a significant reduction in switching losses. In the new energy vehicle industry, SiC can be used in inverters for driving and controlling motors, on-board chargers, and fast-charging stations. In photovoltaic power generation, leading photovoltaic inverter companies have already adopted SiC power devices to replace silicon devices.

[0041] like Figure 1 As shown, traditional SiC devices use rectangular scribe lines 120, which cause stress concentration at the corners, making them prone to cracking. In addition, SiC MOS scribe lines are susceptible to contamination and damage during the dicing process. In particular, if there are cracks in the scribe lines near the die area 110, moisture will enter the die area, and prolonged high-temperature testing will damage the entire wafer, resulting in a decrease in electrical performance parameters.

[0042] To address the aforementioned issues, embodiments of this application provide a silicon carbide device designed to resolve the problems of stress concentration at the corners of rectangular dicing channels in related technologies; and the resulting cracks in the dicing channel during the dicing process leading to moisture intrusion that damages the wafer or degrades its electrical performance parameters.

[0043] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention.

[0044] Figure 2 This is a schematic flowchart of a silicon carbide device according to an embodiment of this application. The silicon carbide device includes:

[0045] The silicon carbide body has the following surface features:

[0046] Multiple die regions 11; each die region has multiple apex corners;

[0047] The dicing channel 12 is formed in the area outside the plurality of core regions, and the area where the dicing channel contacts the apex corner of the core region is arc-shaped;

[0048] The dicing channel includes a first groove 131 disposed around the core region to form a protective coating 132 by depositing a dense material in the first groove.

[0049] In this application, the die region can be an independent, fully functional chip, such as a silicon carbide chip or a MOSFET. Chip-related semiconductor devices and interconnects are all located in the die region. The dicing track is used to cut the wafer, separating the entire wafer into thousands of independent dies.

[0050] The curved section is located at the apex of the die region, curving towards the apex. In other words, the scribe line in this application has a curved section at its corner, and the scribe line has multiple curved sections; the portion where the scribe line connects to the die region is curved. In some embodiments, the silicon carbide body of this application includes a silicon carbide substrate 22, on which a drift region 21 is provided. From the first surface of the silicon carbide, the silicon carbide device is divided into multiple die regions, and a scribe line is provided between any two adjacent die regions. By providing the curved scribe line in this application, the problem of stress concentration at the corners of rectangular scribe lines, which easily leads to cracking, is alleviated in related technologies.

[0051] Optionally, the dicing channel includes multiple dicing channels, each dicing channel being formed by a gap between two adjacent core regions, the minimum width of the dicing channel being in the range of 80 to 100 μm, and the arc shape including a circular arc shape with a radius of 5 to 20 μm.

[0052] The width of the scribe line can be considered as the spacing between adjacent die regions, that is, the scribe line between adjacent die regions is considered as the scribe line. In this application, the scribe line can extend along different directions on the surface of the silicon carbide device. In one embodiment, the first scribe line extends along a first direction, and the width of the first scribe line is the width of the second direction, wherein the first direction and the second direction are perpendicular, and both the first direction and the second direction are parallel to the surface of the silicon carbide body. In another embodiment, the second scribe line extends along a second direction, and the width of the second scribe line is the width of the first direction. In this application, the width of the scribe line can be set to 80 to 100 μm. The width of the scribe line at different locations on the same wafer can be adjusted according to requirements, and this application does not impose a specific limitation. The arc shape can be circular or elliptical, and the radius of the arc shape is set to 5 to 20 μm. The radius of the arc shape at different locations on the same wafer can be different, and the specific value of the radius is set according to requirements. The center (or center of circle) of the arc shape is located on the die region side. The corners of the scribe line in this application adopt an arc design instead of right angles. It helps to disperse stress, reduce the crack initiation rate, and improve the yield.

[0053] Optionally, the depth of the first trench is 0.5 to 1.5 μm, and the aspect ratio of the first trench is 1:1 to 5:1.

[0054] Optionally, the slicing channel includes a second groove 141 disposed around the first groove to form a healing agent layer 142 by applying a healing agent material.

[0055] Optionally, the depth of the second trench is 0.2 to 0.5 μm deeper than the depth of the first trench, and the width of the second trench is wider than the width of the first trench.

[0056] Optionally, the width of the second trench is 1 to 15 μm.

[0057] In some embodiments, the cross-sectional shape of the first trench is square, and the cross-section forming the cross-section is perpendicular to the ground plane of the silicon carbide device. Specifically, it can be rectangular. The depth of the first trench is the maximum distance of the trench in the thickness direction, the depth-to-width ratio of the first trench is the ratio of the depth of the first trench to the width of the first trench, and the width of the first trench is the maximum side length of the first trench in a third direction, which is parallel to the cross-section. In some examples, the third direction can be a first direction or a second direction. In this application, after filling the first trench with a protective coating, a protective coating area 13 is formed. In this application, the protective coating area and the healing agent area are located in the drift area. By setting a protective coating in the first trench, this application prevents moisture from entering the die area from the dicing area and affecting the electrical performance parameters of the wafer, thereby improving the electrical performance parameters of the silicon carbide device.

[0058] Understandably, the measurement methods for the width, depth, and aspect ratio parameters of the second groove are the same as those for the first groove. The aspect ratio of the first groove is 1:1 to 5:1. Both the first and second grooves can be set to a cuboid shape. The cross-sectional shape of the second groove is square, but it can be rectangular. In this application, the second groove is filled to form a healing agent area 14.

[0059] To achieve the above objectives, according to another aspect of this application, a method for fabricating a silicon carbide device is provided, the method comprising:

[0060] Provide wafers; wherein the wafers include multiple die regions;

[0061] By using a preset pattern, scribe lines are formed in the area outside the die region on the wafer surface; wherein the area where the scribe line contacts the apex corner of the die region is arc-shaped;

[0062] A first etching is performed on the dicing channel around the core region to form a first trench; a dense material is deposited in the first trench to form a protective coating.

[0063] This application performs a first etching on the surface of the scribe line at the edge of the scribe line and where it contacts the die region to form a first trench. A dense material is deposited in the first trench, and a protective coating is formed within the first trench. The dense material can be silicon nitride or a high-k material, such as Al2O3. Those skilled in the art can select a suitable dense material according to their needs, and this application does not impose any specific limitations.

[0064] Optionally, the method further includes:

[0065] A second etching is performed at the contact point between the etch path and the first groove to form a second groove; wherein the width of the second groove is wider than the width of the first groove;

[0066] A healing agent material is applied to the second groove to form a healing agent layer.

[0067] This application involves performing a second etching on the surface of the scribe line at the contact point with the first trench to form a second trench. A healing agent material is then deposited in the second trench, forming a healing agent layer within it. The healing agent material can be an epoxy resin composite material containing urea-formaldehyde microcapsules. This healing agent material effectively inhibits crack propagation and improves the lifespan of silicon carbide devices.

[0068] Optionally, the method further includes:

[0069] The depth of the first trench is determined to be 0.5 to 1.5 μm;

[0070] The depth of the second trench is determined to be 0.2 to 0.5 μm deeper than the depth of the first trench.

[0071] Optionally, the method further includes:

[0072] The surface of the silicon carbide device is thinned and a back-side processing is performed to form the silicon carbide device.

[0073] According to another aspect of this application, a new energy device is provided, which is driven by the aforementioned silicon carbide device.

[0074] To enable those skilled in the art to better understand the technical solution of this application, the implementation process of the silicon carbide device of this application will be described in detail below with reference to specific embodiments.

[0075] like Figure 3 As shown, the wafer fabrication process in related technologies involves front-side processing, thinning, back-side processing, process parameter testing, reliability testing, wafer lamination, and dicing to obtain the device. This invention, through an arc-shaped dicing channel design, effectively reduces stress concentration and improves the manufacturing yield of SiC MOSFETs. The dicing channel employs a protective coating + crack healing agent scheme, which can promptly repair cracks generated during the dicing process, and the dense structure of the protective coating can prevent moisture from entering the die area from the dicing channel region and affecting the wafer's electrical performance parameters. To this end, this application adds a process, referring to... Figure 4 As shown, the specific steps include:

[0076] Step S41: After completing all front-side processes, the scribe line is etched for the first time to obtain the first trench. The first etching can use an F-based gas to form the first trench. The depth of the first trench is 0.5-1.5 μm, and the aspect ratio is 1:1-5:1, as shown below. Figure 5 As shown.

[0077] Step S42 involves protective coating filling and etching. A silicon nitride coating is deposited on the scribe line surface using chemical vapor deposition. Alternatively, other high-density materials can be deposited. The dense structure prevents moisture from entering the die area from the scribe line region and affecting the wafer's electrical performance parameters. Common high-k materials include Al₂O₃. Then, the excess silicon nitride coating is etched away. The final morphology is as follows. Figure 6 As shown.

[0078] Step S43: Perform a second etching on the scribe line, using an F-based gas to form a second trench. The second trench is 0.2-0.5 μm deeper than the first trench. This design is to more fully enclose the protective coating area, allowing for the repair of cracks in the coating area and improving long-term device reliability. The second trench is 1-15 μm wide, greater than the width of the first trench, with a depth-to-width ratio of 1:1-5:1. Both the first and second trenches can be cuboid in shape. The final etching morphology is as follows: Figure 7 As shown.

[0079] Step S44: Coat with an epoxy resin composite material containing urea-formaldehyde microcapsules, or other healing agent material. Upon encountering a crack after cutting, the microcapsules rupture, releasing the healing agent. Utilizing self-healing materials to create scribe lines effectively inhibits crack propagation and improves the lifespan of the SiC MOSFET. The final morphology is as follows. Figure 8 As shown.

[0080] The lanes are made like Figure 2 The arc-shaped area shown is defined by photolithography to create a scribe pattern, with corner radii of 5-20 μm. The scribe width is 80-100 μm, and the corners of the scribe are rounded instead of right angles. This helps to distribute stress, reduce crack initiation, and improve yield.

[0081] Step S45, then proceed with the subsequent thinning, back-side process and CP test, wafer-level reliability test, and finally dicing to obtain the silicon carbide device.

[0082] This invention effectively reduces stress concentration and improves the manufacturing yield of SiC MOSFETs through the design of an arc-shaped dicing channel. The dicing channel adopts a protective coating + crack healing agent solution, which can repair cracks generated during the dicing process in a timely manner. In addition, the dense structure of the protective coating can prevent moisture from entering the chip die area from the dicing channel area and affecting the electrical performance parameters of the wafer.

[0083] It should be noted that the above are merely illustrative examples and do not specifically limit the silicon carbide device and its fabrication process.

[0084] In the description of this application, it should be understood that if terms such as "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential" appear, these terms indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this application.

[0085] Furthermore, where the terms "first" and "second" appear, these terms are for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined with "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this application, where the term "multiple" appears, "multiple" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0086] In this application, unless otherwise expressly specified and limited, the terms "installation," "connection," "joining," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components, unless otherwise expressly limited. Those skilled in the art can understand the specific meaning of the above terms in this application based on the specific circumstances.

[0087] In this application, unless otherwise expressly specified and limited, the use of descriptions such as "above" or "below" the second feature indicates that the first and second features are in direct contact or indirect contact via an intermediate medium. Furthermore, "above," "on top of," and "over" the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. Similarly, "below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0088] It should be noted that if an element is referred to as being "fixed to" or "set on" another element, it can be directly on the other element or there may be an intervening element. If an element is considered to be "connected to" another element, it can be directly connected to the other element or there may be an intervening element. If so, the terms "vertical," "horizontal," "upper," "lower," "left," "right," and similar expressions used in this application are for illustrative purposes only and do not represent the only possible implementation.

[0089] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0090] The embodiments described above are merely illustrative of several implementation methods of this application, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the patent application. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the protection scope of this application. Therefore, the protection scope of this patent application should be determined by the appended claims.

[0091] The above description is merely a preferred embodiment of this application and is not intended to limit this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A silicon carbide device, characterized in that, The silicon carbide device includes a silicon carbide body, and the surface of the silicon carbide body is provided with: Multiple die regions; each die region has multiple apex corners; The dicing channel is formed in the area outside the plurality of core regions, and the area where the dicing channel contacts the apex corner of the core region is arc-shaped; The dicing channel includes a first groove surrounding the core region to form a protective coating by depositing a dense material in the first groove.

2. The silicon carbide device according to claim 1, characterized in that, The dicing channel includes multiple dicing channels, each dicing channel being formed by the interval between two adjacent core regions. The minimum width of the dicing channel ranges from 80 to 100 μm, and the arc shape includes a circular arc with a radius of 5 to 20 μm.

3. The silicon carbide device according to claim 1, characterized in that, The depth of the first trench is 0.5 to 1.5 μm, and the depth-to-width ratio of the first trench is 1:1 to 5:

1.

4. The silicon carbide device according to claim 3, characterized in that, The slicing channel includes a second groove arranged around the first groove to form a healing agent layer by applying a healing agent material.

5. The silicon carbide device according to claim 4, characterized in that, The second trench is 0.2 to 0.5 μm deeper than the first trench, and the width of the second trench is greater than the width of the first trench, with the width of the second trench being 1 to 15 μm.

6. A method for fabricating a silicon carbide device, characterized in that, The preparation method includes: A wafer is provided; wherein the wafer includes a plurality of die regions; A scribe line is formed on the wafer surface outside the die region by means of a preset pattern; wherein the area where the scribe line contacts the apex corner of the die region is arc-shaped; A first etching is performed on the dicing channel around the core region to form a first trench; a dense material is deposited in the first trench to form a protective coating.

7. The method for fabricating a silicon carbide device according to claim 6, characterized in that, The method further includes: A second etching is performed around the first groove on the scribe line to form a second groove; wherein the width of the second groove is wider than the width of the first groove; A healing agent material is applied to the second groove to form a healing agent layer.

8. The method for fabricating a silicon carbide device according to claim 7, characterized in that, The method further includes: The depth of the first trench is determined to be 0.5 to 1.5 μm; The depth of the second trench is determined to be 0.2 to 0.5 μm deeper than the depth of the first trench.

9. The method for fabricating a silicon carbide device according to claim 7, characterized in that, The method further includes: The surface of the silicon carbide device is thinned and a back-side processing is performed to form the silicon carbide device.

10. A new energy device, characterized in that, The new energy equipment is driven by a silicon carbide device as described in any one of claims 1 to 5.

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