Substrate having sidewalls, power semiconductor module including the substrate, and method for manufacturing the substrate

Abstract

A substrate (10) for a power semiconductor module is provided, the substrate (10) comprising an integrally formed base body (1). The base body (1) has a front side (1A) and a rear side (1B), the front side (1A) comprising a mounting area (1M) of the substrate (10). The base body (1) has, along at least one of its edges (1E), at least one raised integral part forming at least one side wall (11) projecting beyond the mounting area (1M) by a vertical height (11H). In the region of the mounting area (1M), the base body (1) has a vertical thickness (1T) extending between the front side (1A) and the rear side (1B), the vertical thickness (1T) being greater than the vertical height (11H) of the side wall (11). Further, along all edges (1E), the base body (1) includes either at least one sidewall (11) or at least one groove (12), but not both a sidewall (11) and a groove (12) on the same edge (1E). Along at least one of its edges (1E), the base body (1) includes one raised integral part forming at least one sidewall (11). Further provided is a power semiconductor module (100) including such a substrate (10) and a method for manufacturing such a substrate (10).

Description

[Technical field]

[0001] The present disclosure relates to a substrate having a sidewall, for example for a power semiconductor module, a power semiconductor module including the substrate, and a method for manufacturing the substrate. [Background technology]

[0002] When a semiconductor chip is fixed to a substrate or a substrate is fixed to a board, the wettability of the surfaces can cause the connection material, such as solder, to spread over adjacent surfaces of the substrate or over a large area of ​​the mounting area of ​​the substrate. This overflow of the connection material can cause contamination of areas used for wire bonding, for example, or can result in poor adhesion of encapsulating materials, such as the housing body of a power semiconductor module, leading to delamination. The overflow of the connection material can also result in some of the connection material being lost, and not enough connection material may be available to achieve a very stable connection between the semiconductor chip and the substrate, between the substrate and the board, or between the semiconductor chip and the board.

[0003] If no modifications to the board are introduced, such as to prevent overflow of the connecting material, strong overflow of the connecting material, such as solder, can occur, resulting in undesirable deposition of solder on other areas of the board, particularly on the front side, but also on the sides or rear side of the board.

[0004] To solve these problems, the surface of the substrate or base material can be coated with a solder resist to prevent or reduce wetting of such surface. However, coating a surface with a solder-resistant material requires additional processes in the manufacture of the substrate or base material, which increases the manufacturing cost. In addition, when an organic coating material is used as the solder resist, outgassing of substances from the coating layer adversely affects subsequent process steps for manufacturing the power semiconductor module including the power semiconductor module and the substrate, or the reliability and function of the power semiconductor module. In addition, the use of the solder resist can adversely affect the adhesion of the encapsulant.

[0005] Another approach to prevent overflow of the connection material is to prepare a groove around the mounting area. In the present disclosure, the mounting area is understood to mean the surface of the front side of the substrate for receiving the substrate and / or the module components such as the chip. The surface for fastening, for example for screwing the substrate into a carrier that acts as a cooler, is called the assembly surface. The assembly surface may include the surface outside the mounting area, for example the side wall of the front side of the substrate and / or the outside of the groove. However, it is possible to further call the side and / or rear side of the substrate part of the assembly surface. Here, the overflowed connection material, such as the solder material, can be collected in the groove so that no part or even a small part of the assembly surface of the substrate is contaminated by the connection material. However, the groove needs to be formed sufficiently large, for example, when a thick solder meniscus is to be formed to increase the stability of the solder connection. However, this leads to a reduction in the size of the mounting area. Moreover, on the one hand, if a groove of a sufficiently large size is selected, a large amount of connection material accumulates in the groove. This loss of connection material may result in locally insufficient or missing soldering connections or the formation of voids, for example in the area next to the groove. On the other hand, a small size of the groove around the substrate soldering location may not be sufficient to prevent overflow of the connection material.

[0006] The documents EP 0 577 966 A1, US Patent Application No. 2009 / 224384 A1, US Patent Application No. 2002 / 011661 A1, US Patent No. 6 667 545 B1, US Patent Application No. 2015 / 235929 A1 and JP 2011 258814 describe a component having a substrate or printed circuit board and a semiconductor chip arranged on the substrate or printed circuit board, the substrate or printed circuit board having a structured top surface. Summary of the Invention [Means for solving the problem]

[0007] An embodiment of the present disclosure relates to a substrate for, for example, a power semiconductor module, the substrate including a suitable barrier structure for preventing or reducing overflow of, for example, a connection material. Another object is to provide a highly mechanically stable power semiconductor module including a substrate, the power semiconductor module having improved adhesion and fastening between a surface of the substrate and a housing body, for example a molding. Furthermore, an efficient method for manufacturing the substrate is provided.

[0008] SUMMARY OF THE DISCLOSURE Embodiments of the present disclosure address all or part of the above-mentioned shortcomings in the art. Further embodiments of the substrate, the power semiconductor module including the substrate, and the method for manufacturing the substrate are the subject of further claims.

[0009] According to one embodiment of a substrate, for example used to receive a power semiconductor module, it comprises an integrally formed base body. The base body has a front side and a rear side, the front side comprising the mounting area of ​​the substrate. Along at least one of its edges, the base body has at least one raised integral part forming at least one sidewall projecting beyond the mounting area by a vertical height. In the region of the mounting area, the base body has a vertical thickness extending between the front side and the rear side of the base body, the vertical thickness of the base body being greater than the vertical height of the at least one sidewall.

[0010] The vertical direction is understood to mean a direction oriented perpendicular to the main extension plane of the mounting area or substrate. The lateral direction is understood to mean a direction parallel to the main extension plane of the mounting area or substrate. The vertical and lateral directions are perpendicular to each other.

[0011] The term "along at least one edge" or "at the edge" does not necessarily mean "directly at the edge". The sidewall and possible groove are rather located in the edge region of the front side of the substrate. The sidewall and / or groove can extend over the entire edge region or only in a part of the edge region. The sidewall may be directly adjacent to the side of the substrate, i.e. directly adjacent to the edge or directly at the edge, or it may be laterally spaced from the side of the substrate, i.e. located laterally spaced from the edge. For example, the raised integral part of the substrate forming the sidewall is parallel or substantially parallel to the corresponding edge. If the substrate includes a groove on its front side, the groove is significantly laterally spaced from the edge. The groove can be directly adjacent to the sidewall or laterally spaced from the sidewall. For example, the sidewall is parallel or substantially parallel to the corresponding groove.

[0012] "Substrate formed in one piece" means that the substrate is made in one piece. For example, the substrate does not include separate parts connected to each other using, for example, a connecting material. Rather, the substrate includes only integral parts that are integrally connected to each other, i.e., without the use of additional connecting material. Such integral parts may be formed from the same material.

[0013] The raised integral part of the base may form a single sidewall along only one of the edges of the base. However, the raised integral part of the base may form a single continuous sidewall along multiple edges of the base, such as along exactly two or three edges, or along all edges. Additionally, the raised integral part of the base may form at least two or more than two spatially separated sidewalls along different edges of the base.

[0014] Thus, if the connection material is used to fasten one or more substrates with, for example, a chip on the mounting area of ​​a substrate, one or more side walls, i.e. one or more raised portions of the substrate, can function as one or more barriers to prevent overflow of the connection material. In this case, the power semiconductor module has a substrate and at least one substrate arranged thereon. The power semiconductor module can comprise a single substrate or multiple separated substrates, a single electronic component such as a semiconductor chip or multiple such electronic components, a component or multiple components arranged on a substrate, or multiple components arranged from multiple substrates.

[0015] In the presence of one or more side walls, it is possible that the substrate or base does not have a recess in the form of a groove, i.e. it is a void. Since one or more side walls are formed at the edge of the substrate, the overflow of the connection material, for example the solder material, can be prevented without loss of the connection material accumulated in the groove or in different grooves. Alternatively, a combination of side walls and grooves is possible. However, thanks to the presence of side walls, the size of the groove can be kept small, so that the amount of loss of the connection material is very small and therefore tolerable.

[0016] According to a further embodiment of the substrate, the substrate is made of a metal or a metal alloy. For example, the substrate is made of Cu or Al or a corresponding alloy. Alternatively, the substrate can be made of a non-metallic composite material, for example a composite material containing SiC, for example AlSiC or MgSiC. However, the substrate is not limited to the above materials.

[0017] According to a further embodiment of the substrate, the raised integral part of the base forms at least two side walls that protrude beyond the mounting area. The at least two side walls are arranged along two non-adjacent edges, for example along two opposing edges of the base. Thus, the at least two side walls are spatially separated from each other. In this case, the side walls do not form a continuous barrier, but are rather discontinuous and form two spatially separated barriers on the front side of the base.

[0018] According to a further embodiment of the substrate, the raised integral part of the base body projects beyond the mounting area and forms at least one sidewall completely surrounding the mounting area, in which case the at least one sidewall forms a continuous barrier or a single continuous frame-shaped sidewall.

[0019] According to further embodiments of the substrate, the, or each, sidewall has a vertical height of between 0.05mm and 5.0mm inclusive, for example between 0.5mm and 2mm. The, or each, sidewall may have an average lateral width of between 0.05mm and 10mm inclusive, between 0.05mm and 5mm, or between 0.1mm and 5mm inclusive, typically between 0.5mm and 2mm inclusive.

[0020] According to a further embodiment of the substrate, at least one sidewall is a vertical wall, an inclined wall, or a circular wall. At least one sidewall can be formed partially as a vertical wall, partially as an inclined wall, and / or partially as a circular wall. The shape of the sidewall, for example the cross section of the sidewall, can be square, rectangular, trapezoidal, semicircular, triangular, or another shape.

[0021] However, this disclosure is not intended to limit the geometric dimensions and shapes, e.g., cross-sectional configuration, of the sidewalls to the above dimensions and shapes. The sidewalls can have other shapes or other geometric dimensions.

[0022] According to a further embodiment of the substrate, it comprises at least one groove. The groove can extend along at least one edge of the substrate, or along some edges, or along all edges. Along the lateral direction, the mounting area can be delimited by the groove. Alternatively, it is also possible that the mounting area is delimited by a sidewall, which is located between the mounting area and the groove.

[0023] According to a further embodiment of the substrate, the groove is directly adjacent to at least one sidewall. In this case, the at least one sidewall can extend continuously, for example directly into the groove. Thus, the manufacture of the at least one sidewall and the groove can be carried out in a common manufacturing process or in two subsequent process steps, for example a first process step of forming the at least one sidewall and a second process step of forming the groove, for example using a stamping method. For example, along at least one edge of the substrate, for example along exactly one, exactly two, exactly three edges or along all edges of the substrate, the substrate comprises both at least one sidewall and a groove.

[0024] According to a further embodiment of the substrate, along at least one edge or along several edges, the base body has both at least one sidewall and a groove, in a plan view of the front side of the base body, the groove is located between the mounting area and the at least one sidewall, or the at least one sidewall is located between the mounting area and the groove. It is possible for the groove to be directly adjacent to the at least one sidewall or to be laterally spaced apart from the at least one sidewall.

[0025] In comparison with the case of a substrate without sidewalls, in the presence of sidewalls the grooves can have a reduced lateral width and / or a reduced vertical depth. Thus, the size of the grooves does not have to be selected large enough, so that on the one hand the possible loss of the connection material can be kept small and on the other hand the size of the attachment area can be kept large. Also, depending on the presence of sidewalls and the expected overflow of the connection material, it is possible to design the width and / or depth of the grooves, thus increasing the flexibility of the design of the substrate.

[0026] For example, the width of the groove is between 0.05 mm and 5 mm, inclusive, such as between 0.5 mm and 2 mm. The depth of the groove can be between 0.05 mm and 3 mm, inclusive, such as between 0.05 mm and 2 mm, or between 0.05 mm and 1 mm, inclusive. The shape of the groove can be square, rectangular, trapezoidal, partially circular, semicircular, triangular, or another form. However, the present disclosure is not intended to limit the geometric dimensions and shapes, e.g., the cross-sectional shape of the groove, to those dimensions and shapes described above.

[0027] According to a further embodiment of the substrate, along all edges, the base body includes either at least one sidewall or at least one groove, but not both sidewalls and grooves. For example, the base body includes two sidewalls arranged on two opposite edges of the base body and two grooves arranged on two other edges of the base body. Other combinations of sidewalls and grooves on different edges of the base body are also possible.

[0028] According to a further embodiment of the substrate, it includes a plurality of cooling fins on the rear side of the substrate. The cooling fins can be formed as an integral part of the substrate. In this case, the cooling fins and the sidewalls can be made of the same material. However, the cooling fins can be made of a material different from that of the sidewalls. In this case, the cooling fins can be considered as an additional structure provided on the rear side of the substrate, rather than as an integral part of the substrate.

[0029] According to one embodiment of the power semiconductor module, it comprises a substrate, e.g., a substrate as described herein in this disclosure. The power semiconductor module further comprises a housing body, which laterally, e.g., completely surrounds the substrate. At least one side wall may be completely covered by the housing body and serves as a fastening structure for additionally fastening the housing body to the substrate. The housing body may be a mold body or a body made of a gel material, which may fill the power semiconductor module with the housing frame. However, the housing body is not limited to a mold body or a body made of a gel material.

[0030] According to a further embodiment of the power semiconductor module, it comprises a housing body, which laterally surrounds the substrate, at least one side wall being completely covered by the housing body. The groove can be at least partially filled with the material of the housing body, such that both the at least one side wall and the groove serve as fastening structures for additionally fastening the housing body to the substrate. Some grooves can be partially or completely filled with the material of the housing body, so that the groove can serve as fastening structures for fastening the housing body to the substrate.

[0031] According to a further embodiment of the power semiconductor module, it comprises at least one module component, for example at least one substrate having one or more chips arranged thereon. The module component is fixed to the mounting area by a connection layer. For example, a housing body laterally surrounds the module component. The module component may comprise one or more substrates and / or one or more chips, such as semiconductor chips, electronic or optoelectronic chips, or individual devices such as resistors, capacitors or inductances.

[0032] According to a further embodiment of the power semiconductor module, at least one side wall and / or groove is formed to prevent the material of the connection layer, e.g. a solder material, a sintering material or an adhesive, from creeping towards the side or rear side of the substrate. The connection layer is, for example, a solder, sintering or adhesive layer. Thus, the side wall or the groove or a combination of the side wall and the groove can form a barrier structure that partially or completely surrounds the mounting area to prevent overflow of the connection material.

[0033] By preventing overflow of connecting materials, such as solder overflow, the yield of the process of fastening module components of a power semiconductor module to a substrate can be improved, reducing the overall manufacturing cost. In addition, visual inspection after fastening the power semiconductor module to the mounting area can be exempted. Finally, reducing unnecessary contamination improves the reliability of the semiconductor power module.

[0034] According to one embodiment of the method for manufacturing a substrate, the base body with sidewalls or the entire substrate with or without cooling fins is manufactured in a single common manufacturing process or in two subsequent, e.g., different, manufacturing processes. For example, the base body is manufactured by at least one of forging, stamping, milling, or other machining processes. It is also possible that the base body or the entire substrate with or without cooling fins is formed by a casting process or a molding process.

[0035] When applying a casting or molding process, the sidewalls and / or the grooves of the base body can be prepared by modified molding tools. It is also possible that the cooling fins are formed in the same manufacturing process as the sidewalls and / or the grooves. Therefore, no additional costs are expected for implementing the sidewalls. However, the groove or grooves can be formed subsequently by a machining process, such as stamping or milling, for example by a separate machining process after the sidewalls are formed.

[0036] According to another embodiment of the method for manufacturing a substrate, the base body including at least one sidewall and / or groove is manufactured in a single common casting or molding process. In this case, the sidewall and groove of the base body, even together with, for example, cooling fins, can be prepared by a modified molding tool. Thus, using a casting or any other molding process, the sidewall and groove can be implemented by a slight modification of the casting or molding tool.

[0037] Thus, the sidewalls and the grooves can be formed by two subsequent manufacturing processes. It is also possible to manufacture the substrate including the sidewalls and / or the grooves in a single common manufacturing process.

[0038] The present disclosure includes several embodiments of a substrate, a power semiconductor module including the substrate, and a method for manufacturing the substrate. All features described with respect to one of the embodiments are also disclosed herein with respect to the other embodiments, even if the respective feature is not explicitly mentioned in the context of the particular embodiment. For example, a power semiconductor module may include any of the substrates described herein. The above method is directed to the manufacture of any of the substrates described herein. Thus, features and advantages described in relation to the substrate may be used for the power semiconductor module and the method, and vice versa.

[0039] While the present disclosure is susceptible to various modifications and alternative forms, details thereof have been shown by way of example in the drawings and will be described in detail. It should be understood, however, that the intention is not to limit the disclosure to the particular embodiments described. On the contrary, the intention is to cover all modifications, equivalents, and alternatives falling within the scope of the present disclosure as defined by the appended claims.

[0040] To provide a further understanding, the accompanying figures are included. In the figures, elements of the same structure and / or function may be referenced by the same reference numerals. It should be understood that the embodiments shown in the figures are illustrative representations and are not necessarily drawn to scale. [Brief description of the drawings]

[0041] [Figure 1A] 1 is a perspective view of a substrate on which modular components can be fastened to form a power semiconductor module, according to a comparative example; FIG. [Figure 1B] FIG. 2 is a perspective view of a substrate according to one embodiment. [Figure 1C] 13A-13C are top views of further substrates according to further embodiments. [Figure 1D] 13A-13C are top views of further substrates according to further embodiments. [Figure 2A] 1A-1D are perspective and cross-sectional views of different sections of different substrates having sidewalls and grooves. [Figure 2B] 1A-1D are perspective and cross-sectional views of different sections of different substrates having sidewalls and grooves. [Figure 2C] FIG. 2 is a top view of a substrate according to one embodiment. [Figure 3A] 1 is a cross-sectional view of a power semiconductor module having a substrate according to an embodiment; [Figure 3B] FIG. 11 is a cross-sectional view of a power semiconductor module having a substrate according to another embodiment. [Figure 4A] 4 is a cross-sectional view of a further power semiconductor module having a substrate according to a further embodiment; [Figure 4B] 4 is a cross-sectional view of a further power semiconductor module having a substrate according to a further embodiment; [Figure 4C] 4 is a cross-sectional view of a further power semiconductor module having a substrate according to a further embodiment; [Figure 4D] 4 is a cross-sectional view of a further power semiconductor module having a substrate according to a further embodiment; [Figure 4E] 4 is a cross-sectional view of a further power semiconductor module having a substrate according to a further embodiment; [Figure 4F] 4 is a cross-sectional view of a further power semiconductor module having a substrate according to a further embodiment; [Figure 4G] 4 is a cross-sectional view of a further power semiconductor module having a substrate according to a further embodiment; DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0042] FIGURE 1A, for example, illustrates a substrate 10 for receiving a modular component 30, also shown in FIGURE 1A. This comparative substrate 10 is introduced for comparative purposes and to illustrate some of the technical effects described in this disclosure, and is not to be considered state of the art. The features described in connection with the substrate 10 shown in FIGURE 1A can be used in all embodiments of the substrate 10 of the present disclosure.

[0043] The substrate 10 comprises a standard base body 1 without side walls and grooves. The base body 1 has a front side 1A and a rear side 1B, the front side 1A comprising a mounting area 1M of the substrate 10. A module component 30 can be fixed to the mounting area 1M of the substrate 10 to form a power semiconductor module 100. The substrate 10 has a plurality of cooling fins 3 formed on the rear side 1B.

[0044] The substrate 10 includes a lateral recess 1I on its side 1S. In FIG. 1A, the substrate 10 has two opposing side surfaces 1S, each of the opposing side surfaces 1S having two lateral recesses 1I. For example, the recesses 1I are configured to fasten or screw the substrate 10 to a cooler. For example, the recesses 1I are configured to receive a screw. Along the vertical direction, the recesses can extend from the front side 1A to the rear side 1B of the base 1. Thus, the side surfaces 1S or the rear side 1B are not referred to as attachment areas 1M for receiving module components 30, such as substrates and / or chips, but rather as assembly surfaces 1Z for fastening the substrate 10, for example, to a cooler.

[0045] When a module component 30 of the power semiconductor module 100, such as a substrate, an electronic chip or a semiconductor chip, is fixed to the substrate 10, due to the wettability of the surface, the connection material, such as the solder material of the connection layer 2, may spread over a large area of ​​the mounting area 1M of the base plate 10. This may cause the connection material to overflow. The overflow of the connection material may cause contamination of the edge 1E, the side 1S or the back side 1B of the base 1 or the substrate 10. In addition to the contamination, this also leads to a significant loss of the connection material.

[0046] For example, using scanning acoustic microscope (SAM) photography of a power semiconductor module 100 with components soldered to the mounting area 1M, localized missing solder connections and voids or overflows of solder material can be observed.

[0047] FIG. 1B shows a substrate 10 having a barrier structure for preventing or reducing overflow of the connection material. The substrate 10 comprises an integrally formed base body 1. The base body 1 can be made of a metal or metal alloy, such as Cu or Al, or a composite material, including, but not limited to, SiC, such as AlSiC or MgSiC. Along its edge 1E, the base body 1 has a raised integral part forming at least one sidewall 11 that protrudes beyond the attachment area 1M by a vertical height 11H. The barrier structure is formed, for example, only by the at least one sidewall 11. For example, the at least one sidewall 11 delimits the base body 1 in one or all lateral directions. The at least one sidewall 11 has a lateral width 11W. This lateral width 11W can be considered as the average width 11W of the at least one sidewall 11.

[0048] The base 1 has a vertical thickness 1T extending along the vertical direction between the front side 1A and the rear side 1B. At least in the region of the attachment region 1M, the vertical thickness 1T of the base 1 is greater than the vertical height 11H of the at least one sidewall 11. For example, the vertical thickness 1T of the base 1 is at least 2 times, 3 times, 5 times, or at least 10 times or 20 times greater than the vertical height 11H of the at least one sidewall 11.

[0049] The substrate 1 has a horizontal diagonal width 1W. The horizontal diagonal width 1W can be viewed as the maximum horizontal extension of the substrate 1. For example, the horizontal diagonal width 1W of the substrate 1 is at least 5 times, 10 times, 15 times, 20 times, or at least 50 times greater than the vertical thickness 1T of the substrate 1.

[0050] The vertical height 11H of the at least one side wall 11 may be between 0.05 mm and 2.0 mm inclusive, for example between 0.05 mm and 1.5 mm inclusive, or between 0.05 mm and 10 mm inclusive. The lateral or average lateral width 11W of the at least one side wall 11 may be between 0.05 mm and 10 mm inclusive, for example between 0.1 mm and 5 mm inclusive, between 0.1 mm and 3 mm inclusive, or between 0.1 mm and 1 mm inclusive. In case of doubt, the vertical height 11H and the lateral width 11W of the at least one side wall 11 shall be understood as the average vertical height and average lateral width of the at least one side wall 11, respectively.

[0051] The at least one side wall 11 may have a typical height 11H of 0.15-0.3 mm and a typical width 11W of 0.5 mm. However, other dimensions are possible. The shape of the side wall 11 is not fixed and any shape is possible. However, typical shapes related to the cross section of the side wall 11 may be a square, a rectangle, a trapezoid, a semicircle or a triangle.

[0052] As shown in Figure 1B, the raised integral part of the base 1 forms a single continuous sidewall 11 along all edges 1E of the base 1. The sidewall 11 completely surrounds the mounting area 1M. Unlike Figure 1B, the sidewall 11 can extend only along one edge 1E of the base 1, only along two edges 1E, or only along three edges 1E.

[0053] According to Fig. 1B, the side wall 11 is a partially inclined wall. The side wall 11 has an inner surface 11A facing the mounting area 1M, the inner surface 11A being inclined. The side wall 11 also has an outer surface facing away from the mounting area 1M, the outer surface being a vertical surface. With increasing vertical distance from the mounting area 1M, the cross section of the side wall 11 decreases.

[0054] At least a portion of the attachment area 1M can be coated with a material to achieve improved wettability compared to an uncoated attachment area 1M. At least a portion of the attachment area 1M can be directly formed by the surface of the substrate 1. For example, the attachment area 1M has one or more bonding areas and is covered by the module component 30 after receiving the module component 30. Such bonding areas can be coated with a material to achieve improved wettability (e.g., copper coating, nickel coating, etc.). Solder resist can be applied to areas that should not be wetted, such as around the bonding areas. However, it is possible for the substrate 10 or substrate 1 to be devoid of solder resist, i.e., void.

[0055] The substrate 10 has a number of cooling fins 3 formed on the rear side 1B. The cooling fins 3 can be formed as an integral part of the substrate 1 and can be formed from the same material as the material of the sidewall 11 or the rest of the substrate 1. However, the cooling fins 3 can be made of a material that has a higher thermal conductivity compared to the material of the substrate 1. For example, the cooling fins 3 are the outermost structures of the rear side 1B of the substrate 10. Thus, along the vertical direction, the substrate 10 can be delimited by the cooling fins 3. In this case, the substrate 10 has a structured rear side 1B rather than a planar or flat rear side 1B. The cooling fins 3 can cover more than 20%, 30%, 40%, 50%, or even more than 60% or 70% of the area of ​​the rear side 1B of the substrate 10.

[0056] 1C shows a further substrate 10 according to a further embodiment. The substrate 10 shown in FIG. 1C essentially corresponds to the substrate 10 shown in FIG. 1B. In contrast, the raised integral part of the base 1 forms exactly two side walls 11 that protrude beyond the mounting area 1M. The two side walls 11 are arranged along two opposite edges 1E of the base 1 and are therefore spatially separated from each other. Each of the two side walls 11 extends along the entirety of one edge 1E of the base 1.

[0057] Moreover, contrary to Fig. 1B, according to Fig. 1C, the substrate 10 has two grooves 12 arranged along two separate opposite edges 1E of the base 1. Thus, the two grooves 12 are spatially separated from each other. According to Fig. 1C, along every edge 1E, the base 1 includes either one sidewall 11 or one groove 12, but not both.

[0058] Contrary to FIG. 1C, other combinations of side walls 11 and grooves 12 are possible. For example, the base can have exactly one side wall 11 arranged along one edge and one groove 12 or several grooves 12 along the remaining edge, or vice versa. The base 1 can also have a side wall 11 arranged along exactly two adjacent edges 1E and a groove 12 along the remaining edge 1E, or vice versa. The mounting area 1M can be completely surrounded by side walls 11 and grooves 12. It is also possible that at least one edge 1E or several edges 1E of the base are provided with neither a groove 12 nor one side wall 11.

[0059] It is also possible that the sidewalls 11 are only partially provided around the mounting area 1M. For example, in the case of a square or rectangular substrate 10, the sidewalls 11 may be provided along one to three edges 1E of the substrate 1, but the sidewalls 11 or other structures, such as grooves 12, are not provided on the other three to one edges 1E, respectively. Alternatively, the grooves 12 may be provided on the other three to one edges 1E that do not have sidewalls 11. Furthermore, it is also possible that at least one sidewall 11 and / or at least one groove 12 are provided on a portion of one edge area, but do not extend along the entire edge of the substrate 10.

[0060] Fig. 1D shows a further substrate 10 according to a further embodiment. The substrate 10 shown in Fig. 1D essentially corresponds to the substrate 10 shown in Fig. 1B. In contrast, in the lateral direction, the attachment area 1M is completely surrounded by both the continuous groove 12 and the continuous sidewall 11. Each of the continuous groove 12 and the continuous sidewall 11 is frame-shaped. The continuous groove 12 is located between the continuous sidewall 11 and the attachment area 1M. In the lateral direction, the attachment area 1M is bounded by the groove 12.

[0061] Deviating from Figures 1C and 1D, other combinations of side walls 11 and / or grooves 12 are also possible. For example, the groove 12 can be formed as a continuous groove 12 extending along exactly one, exactly two or exactly three edges 1E of the base 1. Furthermore, it is also possible that the groove 12 completely surrounds the mounting area 1M of the substrate 10, while the side walls 12 do not completely surround the mounting area 1M. As another alternative, the base 1 can comprise exactly two grooves 12 and two side walls 11 arranged on exactly two opposite edges 1E of the base 1.

[0062] FIG 2A shows a detail of section 10S of substrate 10 highlighted in FIG 1D. As shown in FIG 2A, trench 12 is directly adjacent to sidewall 11. Thus, a barrier structure for preventing overflow of connection material is formed by a coherent structure including a sidewall portion and a trench portion. Here, sidewall 11 extends continuously or directly into trench 12.

[0063] As shown in FIG. 2A, the groove 12 has vertical walls and a flat bottom surface. Along the vertical direction, the cross section of the groove 12 is substantially constant. However, the side walls 11 are inclined. Thus, there is a jump or kink in the transition area between the side walls 11 and the groove 12. For example, the side walls 11 have an inner surface 11A that is inclined at 20°-70° or 30°-60° to the mounting area 1M. For example, as shown in FIG. 2A, the inner surface 11A of the side walls 11 is inclined at 45° to the mounting area 1M. The groove 12 has an inner vertical surface that forms an angle of 90° to the mounting area 1M. Thus, FIG. 2A shows a combination of a 45° side wall 11 and a 90° groove 12.

[0064] FIG. 2B shows further geometries of the groove 12 and sidewall 11. For example, there are no jumps or kinks in the transition area between the sidewall 11 and the groove 12. There is a rather smooth transition between the sidewall 11 and the groove 12. On the left side, FIG. 2B shows the combination of a 45° sidewall 11 and a 45° groove 12. On the right side, FIG. 2B shows the combination of a 45° sidewall and a circular groove 12. Along the vertical direction towards the mounting area 1M, the cross section of the groove 12 increases.

[0065] Fig. 2C shows a further substrate 10 according to a further embodiment. The substrate 10 shown in Fig. 2C essentially corresponds to the substrate 10 shown in Fig. 1B, for example. In contrast, the substrate 10 shown in Fig. 2C includes only one single sidewall 11 on the front side 1A of the base body 1. The sidewall 11 does not extend along the entire corresponding edge 1E, but is spaced apart from the side surface 1S. Furthermore, the substrate 10 may be devoid of cooling fins 3.

[0066] 3A shows an embodiment of a power semiconductor module 100 including a substrate 10, e.g. any one of the substrates 10 described above. The power semiconductor module 100 further comprises a housing body 20, which laterally, e.g. completely surrounds the substrate 10. The side walls 11 can be completely covered by the housing body 10 and serve as a fixing structure for additionally fixing the housing body 20 to the substrate 10.

[0067] In a top view, the housing body 20 can partially or completely cover the substrate 10. For example, the housing body 20 can be formed by a molding or casting or filling process.

[0068] The power semiconductor module 100 further comprises a module component 30, which is fixed to the mounting area 1M by means of a connection layer 2. The connection layer 2 can be a solder layer or a sintered layer or an adhesive layer. The housing body 20 can laterally surround, for example, the module component 30 completely. The power semiconductor module 100 comprises, for example, terminals 4 for electrically connecting the module component 30. The terminals 4 can be externally electrically connected at the side of the housing body 20 to an external power supply. The power semiconductor module 100 can comprise a plurality of such terminals 4.

[0069] For example, the module component 30 includes one substrate or multiple laterally separated substrates and / or electronic or optoelectronic chips. The module component 30 can be fixed to the attachment area 1M by a soldering, gluing, sintering process. The connection layer 2 can therefore be a solder layer, a sintering layer, an adhesive layer, or an adhesive layer. For example, the connection layer 2 does not completely cover the attachment area 1M of the substrate 10. However, depending on the spread of the connection material, the connection layer 2 can be at least partially directly adjacent to the sidewall 11 of the base 1, or directly adjacent to the groove 12 if the groove 12 is on the inside and the sidewall 11 is on the outside.

[0070] In the vertical direction, the side walls 11 can protrude beyond the connection layer 2. In the lateral direction, the module component 30 can be surrounded by the side walls 11 and / or the grooves 12. The grooves 12 can be partially or completely filled with the material of the connection layer 2. Such a case can occur, for example, in the power semiconductor module 100 shown in FIG. 3B. Along the vertical direction, the rear side of the module component 30 or a component of the module component 30 can be located below the upper surface of the side walls 11, while the front side of the module component 30 can be arranged above the upper surface of the side walls 11. In other words, the module component 30 is not located completely above the side walls 11.

[0071] Fig. 3B shows a further power semiconductor module 100 according to a further embodiment. The power semiconductor module 100 shown in Fig. 3B substantially corresponds to the power semiconductor module 100 shown in Fig. 3A. In contrast, the substrate 10 or the base body 1 of the substrate 10 shown in Fig. 3B comprises at least one side wall 11 and at least one groove 12. The side wall 11 and / or the groove 12 are formed to prevent the material of the connection layer 2 from creeping towards the side side 1S or the rear side 1B of the base body 1 before the housing body 20 is formed.

[0072] For example, the groove 12 is at least partially filled or completely filled with the material of the housing body 20, such that both the side wall 11 and the groove 12 act as fastening structures for additionally fastening the housing body 20 to the substrate 10. It is also possible that the groove 12 is partially filled with the material of the connecting layer 2 and partially filled with the material of the housing body 20.

[0073] A conventional power semiconductor module 100 comprising a substrate 10 covered or surrounded by a housing body 20 may have insufficient stability between the substrate 10 and the housing body 20 due to poor adhesion between the housing body 20 and the substrate 10. Using the side walls 11 and / or grooves 12 as a fixing structure may enlarge the contact surface on the one hand and allow the housing body 20 to engage with the fixing structure on the other hand, thereby improving the stability of the power semiconductor module 100. For example, especially when the housing body 20 is a mold body, the side walls 11 and / or grooves 12 may improve the overall molding by reducing the risk of mold edge breakage and preventing delamination at the interface between the substrate 10 and the housing body 20, because more contact surface is provided for the housing body 20 and the side walls 11 and / or grooves 12 may function as a fixing structure for the housing body 20.

[0074] Instead of using the grooves 12 to prevent overflow of the connection material, the loss of the connection material in the grooves 12 can be prevented by using side walls 11 or raised parts at the edges 1E of the substrate 10. Alternatively, a combination of side walls 11 and grooves 12 is possible, with the grooves 12 being provided as an inner part of the barrier structure and the side walls 11 as an outer part of the barrier structure. Thanks to the presence of the side walls 11, the grooves 12 can be kept small, so that only very small and tolerable losses of the connection material occur. Depending on the design, the module can also be partially implemented, for example, in terms of space, with the side walls 11 or / and the grooves 12, with or without the grooves 12 at different ends 1E of the base 1 or substrate 10.

[0075] 4A to 4G show some exemplary embodiments of a power semiconductor module 100. The power semiconductor module 100 shown in FIG. 4A is essentially the power semiconductor module 100 shown in FIG. 3A. In FIG. 4A, the housing body 20 and the terminals 4 are not shown, only for the sake of clarity and to provide a better comparison with further embodiments of the power semiconductor module 100 shown in FIGS. 4B to 4G. According to FIG. 4A, the side wall 11 is directly adjacent to the side surface 1S. The side wall 11 is therefore arranged directly at one edge of the base body 1.

[0076] The power semiconductor module 100 shown in Fig. 4B substantially corresponds to the power semiconductor module 100 shown in Fig. 4A. In contrast, in a top view, the side wall 11 is spaced apart from a corresponding side surface 1S. Thus, the side wall 11 is laterally spaced apart from a corresponding one edge of the base body 1.

[0077] The power semiconductor module 100 shown in Fig. 4C substantially corresponds to the power semiconductor module 100 shown in Fig. 4B. In contrast, in at least one edge region of the front side 1A of the base body 1, the base body 1 has several side walls 11, in this case three side walls 11. The side walls 11 can be directly adjacent to one another or can be laterally spaced apart from one another. For example, the side walls 11 are parallel or substantially parallel to one another.

[0078] The power semiconductor module 100 shown in Fig. 4D essentially corresponds to the power semiconductor module 100 shown in Fig. 4B. In contrast, in at least one edge region of the front side 1A of the base body 1, the base body 1 has one groove 12 directly adjacent to the side wall 11. The groove 12 is located between the side wall 11 and the mounting area 1M.

[0079] The power semiconductor module 100 shown in Fig. 4E substantially corresponds to the power semiconductor module 100 shown in Fig. 4D. In contrast, in at least one edge region of the front side 1A of the base body 1, the base body 1 has one groove 12 located between two side walls 11. As shown in Fig. 4E, the groove 12 can be directly adjacent to both side walls 11. It is also possible that the groove 12 is laterally spaced apart from both side walls 11 or is directly adjacent to one side wall 11 and spaced apart from the other side wall 11.

[0080] The power semiconductor module 100 shown in Fig. 4F substantially corresponds to the power semiconductor module 100 shown in Fig. 4D. In contrast, the positions of the side wall 11 and the groove 12 are exchanged. The groove 12 is located between the side surface 1S and the side wall 11. The mounting area 1M can be delimited by the side wall 11 between the mounting area 1M and the groove 12.

[0081] The power semiconductor module 100 shown in Fig. 4G essentially corresponds to the power semiconductor module 100 shown in Fig. 4D or 4E. In contrast, in at least one edge region of the front side 1A of the base body 1, the base body 1 has one or more grooves 12 and two or more side walls 11, here two grooves 12 and three side walls 11. Each of the grooves 12 is arranged between the two side walls 11 and can be directly adjacent or spaced apart from at least one of the two side walls 11. Also, each of the side walls 11 is arranged between the two grooves 12 and can be directly adjacent or spaced apart from at least one of the two grooves 12.

[0082] In Figures 4A-4G only partial cross-sectional views of the substrate 10 or the power semiconductor module 100 are shown. The side walls 11, the grooves 12 or possible combinations of side walls 11 and grooves 12 can be arranged exactly along one edge 1E of the base 1, exactly along two adjacent or opposing edges 1E, exactly along three edges 1E or along all edges 1E, i.e. in exactly one edge region, exactly two adjacent or opposing edge regions, exactly three edge regions or all edge regions, respectively, on the front side 1A of the base 1. The side walls 11 and / or the grooves 12 can extend along the entire edge region or several parts of the edge region, as shown for example in Figure 2C.

[0083] Further embodiments of the present disclosure are provided below, where the numbers used below are intended to facilitate reference to features of other embodiments.

[0084] Embodiment 1: A substrate for a power semiconductor module, the substrate comprising an integrally formed base body having a front side and a rear side, the front side including a mounting area for the substrate along at least one of the edges of the substrate, the base having at least one raised integral part forming at least one sidewall in the region of the mounting area that projects beyond the mounting area by a vertical height, the base having a vertical thickness extending between the front side and the rear side, the vertical thickness being greater than the vertical height of the sidewall.

[0085] Embodiment 2: A substrate as described in embodiment 1, wherein the raised integral part forms at least two side walls that protrude beyond the mounting area, the at least two side walls being disposed along two non-adjacent or opposing edges of the base.

[0086] Embodiment 3: The substrate of embodiment 1, wherein the sidewall completely surrounds the mounting area. Embodiment 4: A substrate according to one of embodiments 1 to 3, wherein at least one sidewall has a vertical height of between 0.05 mm and 5.0 mm (inclusive) and an average lateral width of between 0.05 mm and 10 mm (inclusive).

[0087] Embodiment 5: A substrate according to one of embodiments 1 to 4, comprising a plurality of cooling fins on its rear side.

[0088] Embodiment 6: The substrate according to one of embodiments 1 to 5 further comprises at least one groove extending along at least one of the edges of the base, and along the lateral direction, the attachment areas are delimited by the groove.

[0089] Embodiment 7: A substrate according to one of the embodiments 1 to 6, having both at least one sidewall and a groove along at least one of its edges, or along several of its edges, and in a plan view of the front side of the substrate, the groove is disposed between the mounting area and the at least one sidewall.

[0090] Embodiment 8: Along at least one of its edges, or along some of its edges, the base has both at least one sidewall and a groove, and in a plan view of the front side of the base, the sidewall is disposed between the mounting area and the groove: a substrate described in one of embodiments 1 to 5.

[0091] Embodiment 9: A substrate according to any one of embodiments 6 to 8, wherein the groove is directly adjacent to at least one sidewall.

[0092] Embodiment 10: A substrate according to one of embodiments 1 to 6, wherein along all edges the base comprises either at least one sidewall or at least one groove, but does not comprise both a sidewall and a groove on the same edge.

[0093] Embodiment 11: A substrate according to one of embodiments 1 to 9, wherein along at least one common edge, the base comprises at least two sidewalls and at least one groove, or at least one sidewall and at least two grooves.

[0094] Embodiment 12: A power semiconductor module comprising a substrate according to one of the preceding embodiments, further comprising a housing body, the housing body laterally surrounding the substrate, the side walls being covered by the housing body and functioning as a fixing structure for additionally fixing the housing body to the substrate.

[0095] Embodiment 13: A power semiconductor module comprising a substrate according to one of embodiments 6 to 11, further comprising a housing body, the housing body laterally surrounding the substrate, the side walls being covered by the housing body, and the groove being at least partially filled by the material of the housing body, such that both the side walls and the groove function as fixing structures for additionally fixing the housing body to the substrate.

[0096] Embodiment 14: A power semiconductor module according to one of embodiments 12 to 13, further comprising a module component, the module component being fixed to the mounting area by a connection layer, and the housing body laterally surrounding the module component.

[0097] Embodiment 15: A power semiconductor module as described in embodiment 14, wherein the side walls and / or grooves are formed to prevent the material of the connection layer from creeping towards the assembly surface.

[0098] The embodiments shown in the figures described represent exemplary embodiments of the improved arrangement of the substrate and the power semiconductor module including the substrate. Therefore, they do not constitute a complete list of all embodiments of the improved arrangement of the substrate and the power semiconductor module including the substrate. The actual arrangement of the substrate or the power semiconductor module may differ from the exemplary embodiments described above.

[0099] This application claims priority from European patent application EP 21 161 711.3, the disclosure of which is incorporated herein by reference. [Explanation of symbols]

[0100] Reference symbol 100 Power Semiconductor Module 10 Substrate 10S board part 20 Housing body 30 Module components / substrates / semiconductor chips 1 Base 1A Front side of the base 1B Back side of the base 1S Side of the base / substrate 1E Base edge 1M Base / Substrate Mounting Area 1T Vertical thickness of the substrate 1W Diagonal width of the base 1I Horizontal depression in the base 1Z Assembly surface 11 Side wall of base 11A Inner surface of side wall 11H Vertical height of side wall 11W Average width of side wall 12 Groove in base 2. Connection Layer 3 Cooling fins 4 Terminals

Claims

1. A substrate (10) for a power semiconductor module, comprising: said substrate (10) comprises an integrally formed base body (1), said base (1) has a front side (1A) and a rear side (1B), said front side (1A) comprising an attachment area (1M) of said substrate (10); - the base body (1) has a plurality of edges (1E), the plurality of edges (1E) extending along directions intersecting each other; - along at least one of said edges (1E), said base (1) has at least one raised integral part forming at least one side wall (11) projecting a vertical height (11H) beyond said mounting area (1M); - in the region of said attachment area (1M), said base body (1) has a vertical thickness (1T) extending between said front side (1A) and said rear side (1B), said vertical thickness (1T) being greater than said vertical height (11H) of said at least one side wall (11); and - along all said edges (1E), said base (1) comprises either at least one sidewall (11) or at least one groove (12), but not both said at least one sidewall (11) and said at least one groove (12) on the same said edge (1E) of the plurality, and along at least one of said edges (1E), said base (1) comprises one raised integral part forming said at least one sidewall (11).

2. 2. The substrate (10) of claim 1, wherein the raised integral part forms at least two side walls (11) protruding beyond the mounting area (1M), the at least two side walls (11) being arranged along two non-adjacent or opposite edges (1E) of the base body (1).

3. The substrate (10) of claim 1, wherein the base (1) comprises two side walls (11) arranged on two opposing edges (1E) and two grooves (12) arranged on two separate edges (1E) of the base (1).

4. The substrate (10) of any one of claims 1 to 3, wherein the at least one side wall (11) has a vertical height (11H) of between 0.05 mm and 5.0 mm, inclusive, and an average lateral width (11W) of between 0.05 mm and 10 mm, inclusive.

5. The substrate (10) according to any one of claims 1 to 4, comprising a plurality of cooling fins (3) on said rear side (1B).

6. The substrate (10) according to any one of claims 1 to 5, wherein the at least one groove (12) extends along at least one of the edges (1E) of the base body (1), and along a lateral direction, the mounting area (1M) is delimited by the at least one groove (12).

7. The substrate (10) according to any one of claims 1 to 6, wherein the at least one side wall (11) is a vertical wall.

8. The substrate (10) according to any one of claims 1 to 6, wherein the at least one side wall (11) is an inclined wall.

9. The substrate (10) of any one of claims 1 to 6, wherein the at least one side wall (11) is a circular wall.

10. The substrate (10) according to any one of the preceding claims, wherein the at least one side wall (11) is formed partly as a vertical wall and partly as an inclined wall.

11. The substrate (10) according to any one of the preceding claims, wherein the at least one side wall (11) is formed partly as a vertical wall and partly as a circular wall.

12. A power semiconductor module (100) comprising the substrate (10) according to any one of claims 1 to 11, further comprising a housing body (20), - said housing body (20) laterally surrounds said substrate (10); - a power semiconductor module (100), said at least one side wall (11) being covered by said housing body (20) and serving as a fixing structure for additionally fixing said housing body (20) to said substrate (10).

13. A power semiconductor module (100) including the substrate (10) according to any one of claims 1 to 11, further comprising a housing body (20), - said housing body (20) laterally surrounds said substrate (10); - a power semiconductor module (100), wherein the at least one side wall (11) is covered by the housing body (20) and the at least one groove (12) is at least partially filled with the material of the housing body (20), so that both the at least one side wall (11) and the at least one groove (12) act as fixing structures for additionally fixing the housing body (20) to the substrate (10).

14. A power semiconductor module (100) according to any one of claims 12 to 13, further comprising a module component (30), said modular component (30) is fixed to said mounting area (1M) by a connecting layer (2); - a power semiconductor module (100), said housing body (20) laterally surrounding said modular component (30).

15. The power semiconductor module (100) according to claim 14, wherein the at least one side wall (11) and / or the at least one groove (12) are formed to prevent material of the connection layer (2) from creeping towards an assembly surface (1Z).

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