Semiconductor package, power electronic system, and method for coupling semiconductor package to heat sink

Abstract

The invention relates to a semiconductor package, a power electronic system and a method for coupling the semiconductor package to a heat sink. A semiconductor package includes a molded body including a first side and an opposite second side; at least one semiconductor die encapsulated by the molded body; and a die carrier comprising a first side and an opposite second side wherein the at least one semiconductor die is arranged over the first side of the die carrier, and wherein the second side of the die carrier is at least partially exposed from the second side of the molded body to form at least one exposed portion of the die carrier, the first side of the molded body comprises a first portion and a second portion, where the first portion protrudes from the second portion in a vertical direction to form a flat surface, where the vertical direction is perpendicular to the first side of the molded body, where the second portion extends entirely along at least one edge of the first side of the molded body, and where the first portion protrudes from the second portion in a vertical direction to form a flat surface. A center point of the first portion is vertically aligned with a center point of the exposed portion.

Description

TECHNICAL FIELD

[0001] The present disclosure generally relates to semiconductor packages, in particular to semiconductor packages where a first portion of a first side of a mold body protrudes perpendicularly from a second portion, and the present disclosure generally also relates to power electronic systems comprising a semiconductor package and a heat sink and to methods for coupling a semiconductor package to a heat sink. BACKGROUND

[0002] Semiconductor packages can comprise one or more semiconductor dies and a mold body configured to protect the one or more semiconductor dies from the environment. Such semiconductor packages can be configured to be coupled to a heat sink configured to dissipate heat generated by the one or more semiconductor dies during operation. Such coupling can be accomplished, for example, by sintering, soldering, clamping, or screwing the semiconductor package to the heat sink. However, manufacturing tolerances can cause the semiconductor package to become tilted with respect to the heat sink during the coupling process, which can result in unsatisfactory thermal and / or mechanical properties of the coupling. Furthermore, the pressure applied to the semiconductor package during the coupling process can cause the semiconductor package to be damaged if too much pressure is applied to certain portions of the semiconductor package, for example to the edge regions of the semiconductor package. Improved semiconductor packages, improved power electronic systems comprising semiconductor packages, and improved methods for coupling semiconductor packages to heat sinks can help to address these and other issues. SUMMARY

[0003] Various aspects relate to a semiconductor package comprising: a mold body comprising a first side and an opposite second side; at least one semiconductor die encapsulated by the mold body; and a die carrier comprising a first side and an opposite second side, wherein the at least one semiconductor die is arranged on the first side of the die carrier, and wherein the second side of the die carrier is at least partially exposed from the second side of the mold body to form at least one exposed portion of the die carrier, wherein the first side of the mold body comprises a first portion and a second portion, wherein the first portion protrudes in a perpendicular direction from the second portion to form a flat surface, wherein the perpendicular direction is perpendicular to the first side of the mold body, wherein the second portion extends completely along at least one edge of the first side of the mold body, and wherein a center point of the first portion is vertically aligned with a center point of the exposed portion.

[0004] Various aspects relate to a power electronic system comprising: a semiconductor package as described above and a heat sink, wherein the semiconductor package is mechanically coupled to the heat sink such that the second side of the semiconductor package faces the heat sink.

[0005] Various aspects relate to a method for mechanically coupling a semiconductor package to a heat spreader, the method comprising: providing a semiconductor package comprising: a molding body comprising a first side and an opposite second side; at least one semiconductor die encapsulated by the molding body; and a die carrier comprising a first side and an opposite second side, wherein the at least one semiconductor die is arranged on the first side of the die carrier, and wherein the second side of the die carrier is at least partially exposed from the second side of the molding body to form at least one exposed portion of the die carrier, wherein the first side of the molding body comprises a first portion and a second portion, wherein the first portion protrudes in a perpendicular direction from the second portion to form a flat surface, wherein the perpendicular direction is perpendicular to the first side of the molding body, wherein the second portion extends completely along at least one edge of the first side of the molding body, and wherein a center point of the first portion is vertically aligned with a center point of the exposed portion; arranging the semiconductor package on a heat spreader such that the second side of the semiconductor package faces the heat spreader; and applying pressure onto the first portion of the first side of the molding body but not onto the second portion of the first side of the molding body in order to mechanically and thermally couple the semiconductor package to the heat spreader.

[0006] Those skilled in the art will recognize additional features and advantages upon reading the following detailed description, and upon viewing the accompanying drawings. BRIEF DESCRIPTION OF DRAWINGS

[0007] The figures in the accompanying drawings illustrate aspects of the present disclosure by way of example and not by way of limitation, in which like reference numerals refer to similar or identical elements. The elements in the figures are not necessarily to scale relative to each other. Features of various illustrated examples can be combined, unless they are mutually exclusive.

[0008] Figure 1 A cross-sectional view of a semiconductor package is shown, in which the first side of the molding body comprises a first portion that protrudes perpendicularly from a second portion of the first side.

[0009] Figure 2 A cross-sectional view of a semiconductor package is shown, in which the first side of the molding body comprises a first portion that protrudes perpendicularly from a second portion of the first side. Figure 1

[0010] Figures 3A to 3C Another example semiconductor package is shown that comprises a molding body having a first portion and a second portion.

[0011] Figures 4A to 4D A power electronics system is shown that comprises a semiconductor package that is coupled to a heat spreader via a clamp​Figure 4A and Figure 4B coupled to the substrate via a screw Figure 4C and via a sintered layer Figure 4D .

[0012] Figure 5 is a flowchart of an exemplary method for coupling a semiconductor package to a heat spreader.

[0013] Figure 6 shows another exemplary semiconductor package including a molded body having a first portion including separate islands.

[0014] Figure 7 shows a cross-sectional view of coupling the semiconductor package of Figure 6 to a heat spreader using a press, where the press applies different pressures on the islands of the first portion. DETAILED DESCRIPTION

[0015] In the following detailed description, known structures and elements are illustrated by schematic form to facilitate description of one or more aspects of the disclosure. In this regard, directional terminology, such as "top," "bottom," "leading," "trailing," etc., is used with reference to the orientation of the Figure(s) being described. Because components of the present disclosure can be positioned in a number of orientations, the directional terminology is used for purposes of illustration only. It is to be understood that other examples can be utilized and structural or logical changes can be made without departing from the scope of the present disclosure.

[0016] Furthermore, although a particular feature or aspect of an example can have been disclosed with respect to only one of several embodiments, such feature or aspect can be combined with one or more other features or aspects of the other embodiments as can be desired and advantageous for any given or particular application, unless specifically noted otherwise or unless the technical scope of the disclosure would clearly be limited thereto. Moreover, just as individual features or aspects of an example can be combined with other examples, features or aspects of different examples can also be combined with each other, unless specifically noted otherwise or unless the technical scope of the disclosure would clearly be limited thereto. Furthermore, as used herein, the terms "comprises," "comprising," "includes," "including," "has," "having," "contains," "containing," or the like are intended to be open-ended terms that do not exclude additional elements or steps. Terms such as "coupled" and "connected" and variations thereof are intended to encompass a direct connection between elements or a connection that is not direct, such as through intervening elements or layers. However, "coupled" or "connected" elements can also be directly connected to each other. Further, the term "exemplary" is used herein to merely mean an example, rather than the best or optimal example. Thus, the disclosure is not intended to be limited to the examples described herein, but is to be accorded the full scope consistent with the claims, to

[0017] In several examples, layers or layer stacks are applied on top of each other, or material is applied or deposited onto a layer. It is to be understood that any terms such as “applying” or “depositing” are intended to literally encompass all types and techniques of applying layers on top of each other. In particular, they are intended to encompass techniques in which layers are applied as a whole at once, e.g. lamination techniques, and they are intended to encompass techniques in which layers are deposited in a sequential manner, e.g. sputtering, plating, molding, CVD, etc.

[0018] Efficient semiconductor packages, efficient power electronic systems, and efficient methods for coupling semiconductor packages to a substrate, such as a heat sink, can for example reduce material consumption, ohmic losses, chemical waste, etc., and thus can enable energy and / or resource savings. As specified in this specification, improved semiconductor packages, improved power electronic systems, and improved methods for coupling semiconductor packages to a substrate, such as a heat sink, can thus at least indirectly contribute to a green technology solution, i.e. to a climate-friendly solution that provides mitigation of energy and / or resource usage.

[0019] Figure 1 A cross-sectional view of a semiconductor package 100 comprising a molding body 110, at least one semiconductor die 120, and a die carrier 130 is shown. The semiconductor package 100 can for example be a power semiconductor package configured to operate at high voltages (e.g. voltages of 100 V or more, or voltages of 200 V or more, or voltages of 500 V or more, or voltages of 1 kV or more) and / or at strong currents (e.g. currents of 1 A or more, or currents of 10 A or more, or currents of 100 A or more). The semiconductor package 100 can be configured for use in any suitable application, e.g. for use in automotive applications, industrial applications, home applications, etc.

[0020] The semiconductor package 100 can comprise any suitable circuit, or the semiconductor package 100 can be configured as part of any suitable circuit. For example, the semiconductor package 100 can comprise a half-bridge circuit, a full-bridge circuit, a converter circuit, an inverter circuit, etc.

[0021] The molding body 110 comprises a first side 111 and an opposite second side 112. The molding body 110 can further comprise a side edge 113 connecting the first side 111 and the second side 112. The molding body 110 can have any suitable shape and any suitable dimensions. For example, the molding body 110 can have a substantially rectangular or square shape when viewed from above the first side 111. According to one example, the first side 111 and the second side 112 can have the same or substantially the same shape and / or dimensions. The first side 111 and the second side 112 can be those sides of the molding body 110 that are the sides with the largest surface area among any of the sides of the molding body 110.

[0022] The molded body 110 can be manufactured using any suitable manufacturing process, such as compression molding, injection molding, or transfer molding. The molded body 110 may include or be composed of any suitable molding material. According to one example, the molded body 110 may also include inorganic filler particles configured to reduce the thermal resistance of the molded body 110.

[0023] At least one semiconductor die 120 is encapsulated by a molding compound 110. The molding compound 110 may be configured to protect the at least one semiconductor die 120 from environmental influences. The at least one semiconductor die 120 may be any suitable type of semiconductor die, such as a power semiconductor die. The at least one semiconductor die 120 may, for example, include a vertical transistor structure or a lateral transistor structure.

[0024] exist Figure 1 In the example shown, semiconductor package 100 includes two semiconductor dies 120. However, semiconductor package 100 may include any suitable number of semiconductor dies 120, such as one, two, four, six, etc. Furthermore, more than one semiconductor die 120 may all be of the same type or different types of dies. Note that, for simplicity, Figure 1 The internal electrical connections of the semiconductor package 100 are not shown.

[0025] The die carrier 130 includes a first side 131 and an opposing second side 132. At least one semiconductor die 120 is disposed on the first side 131 of the die carrier 130. Furthermore, the second side 132 of the die carrier 130 is at least partially exposed from the second side 112 of the molding body 110. In other words, the die carrier 130 may include at least one exposed portion not covered by the molding body 110.

[0026] At least one exposed portion of the die carrier 130 may be configured to be mechanically and thermally connected to a heat sink and / or substrate. Such connections may include, for example, sintering, soldering, screwing, or clamping the semiconductor package 100 to the heat sink and / or substrate.

[0027] exist Figure 1 In the example shown, the die carrier 130 includes a single exposed portion. However, the die carrier 130 may include any suitable number of exposed portions, such as one, two, three, four, etc. The exposed portions may be arranged, for example, in lines, matrices, etc., on the second side 112 of the molded body 110.

[0028] The die carrier 130 can be any suitable type of die carrier, such as direct copper bonding (DCB), direct aluminum bonding (DAB), active metal brazing (AMB), insulated metal substrate (IMS), printed circuit board (PCB), leadframe, etc. The die carrier 130 can for example be a power electronic substrate. The die carrier 130 can for example comprise two electrically conductive layers 133, 134 separated from each other by an electrically insulating layer 135.

[0029] As shown in Figure 1 the first side 111 of the molding 110 comprises a first portion 114 and a second portion 115. The first portion 114 protrudes in a vertical direction from the second portion 115, wherein the vertical direction is perpendicular to the first side 111. Further, the first portion 114 forms a flat surface. The flat surface can be parallel to the second side 132 of the die carrier 130, in particular parallel to an exposed portion of the die carrier 130.

[0030] In the example shown in Figure 1 the first side 111 comprises a slope between the flat surface of the first portion 114 and the second portion 115. The slope can for example be arranged at an angle in the range of about 30° to slightly less than 90° with respect to the flat surface. However, the first side 111 can also comprise a vertical step between the first portion 114 and the second portion 115.

[0031] The semiconductor package 100 can comprise external contacts, which can for example be exposed from one or more of the side edges 113 and / or the first side 111 (not shown in Figure 1 ). The external contacts can for example be power contacts, such as direct current contacts and one or more phase current contacts, as well as control contacts, sensing contacts, etc. The power contacts can for example be exposed from one or more of the side edges 113, and the control or sensing contacts can for example be exposed from the first side 111, in particular the first region 114 and / or the second region 115. The power contacts can for example comprise or consist of metal clamps. The control or sensing contacts can for example comprise or consist of pins.

[0032] The semiconductor package 100 can have any suitable size and any suitable shape. For example, the semiconductor package can have a substantially square or rectangular shape when viewed from above the first side 111. The semiconductor package 100 can for example have an edge length in the range of about 5 mm to about 10 cm when viewed from above the first side 111. The first portion 114 can for example account for about 30% or more, or about 50% or more, or about 70% or more, or about 90% or more of the surface area of the first side 111.

[0033] The second portion 115 extends completely along at least one edge of the first side 111 (or, in other words, along one of the plurality of side edges 113 of the molded body 110). The second portion 115 can also extend completely along two edges of the first side 111 (e.g., along two opposite edges) or along three edges of the first side 111 or along all four edges of the first side 111. In other words, the first portion 114 can be completely surrounded by the second portion 115.

[0034] Furthermore, a center point of the first portion 114 is vertically aligned with a center point of the exposed portion of the die carrier 130. This is indicated in Figure 1 by the vertical line z. In case the exposed portion of the die carrier 130 is the center of the die carrier 130, the center point of the first portion 114 is generally vertically aligned with the center point of the die carrier 130. In this regard, the “center point” is the center of the surface area of the first portion 114, respectively of the exposed portion, when viewed from above, respectively from below.

[0035] According to Figure 1 the example shown, the first portion 114 is arranged inboard of the periphery of the at least one exposed portion of the die carrier 130 and the second portion 115 is at least partially arranged outboard of the periphery of the exposed portion. This is indicated in Figure 1 by the two dashed lines between the first portion 114 and the second portion 115. According to one example, at least 50% of the second portion 115 is arranged outboard of the periphery of the exposed portion of the die carrier 130.

[0036] In the example shown in Figure 1 , the periphery of the exposed portion of the die carrier 130 and the periphery of the first portion 114 of the first side 111 of the molded body 110 are substantially completely aligned. According to another example, the exposed portion of the die carrier 130 can be smaller than the first portion 114, such that the periphery of the exposed portion is arranged inboard of the periphery of the first portion 114. According to yet another example, it is the other way around as described above. However, in either case, the center point of the first portion 114 and the center point of the exposed portion of the die carrier 130 are vertically aligned along the line z.

[0037] The above-described arrangement of the first portion 114 and the exposed portion of the die carrier 130 relative to each other can have the following benefit: As described above, the semiconductor package 100 can be configured to be connected to a substrate, such as a heat sink and / or a substrate, such that the second side 112 of the molded body 110 faces the substrate. Connecting the semiconductor package 100 to the substrate can comprise exerting a pressure onto the first side 111 of the molded body 110 and onto the substrate (and thus onto the exposed portion of the die carrier 130). Figure 2An example of this connection process is shown in FIG. 3, in which the semiconductor package 100 and the substrate 210 are arranged in the press 200. As shown, pressure is applied to the first portion 114 of the first side 111 of the molding body 110 but not to the second portion 115 of the first side 111 of the molding body 110. Since the first portion 114 is in vertical alignment with the exposed portion of the die carrier 130 (as described further above), the pressure can be distributed evenly over the exposed portion of the die carrier 130. For this reason, a joint of uniform thickness (e.g., a sintered joint) can be made between the semiconductor package 100 and the substrate 210. Figure 2

[0038] If the first portion 114 is not present, i.e., if the first side 111 of the molding body 110 is flat, then due to alignment tolerances between the semiconductor package 100 and the substrate 210 on the one hand and between the semiconductor package 100 and the press 200 on the other hand, the pressure applied to one edge region of the first side 111 can be higher than the pressure applied to the opposite second edge region of the first side 111. This can, for example, result in a tilted joint between the semiconductor package 100 and the substrate 210 and / or it can result in a joint that is made defective. In other words, the protruding first portion 114 that is in alignment with the exposed portion of the die carrier 130 can help to make a joint of uniform thickness. This can, for example, improve the thermal and / or mechanical properties of such a joint.

[0039] The above-described alignment between the first portion 114 and the exposed portion of the die carrier 130 can have a further benefit: As shown in the example of FIG. 4, the die carrier 130 can include an insulating layer 135 that can protrude laterally from the electrically conductive layers 133, 134. The insulating layer 135 can, for example, include or consist of a ceramic layer and can be relatively brittle. If the press 200 were to apply pressure to the second region 115, the insulating layer 135 can crack in the event that the pressure becomes too high. However, the configuration of the semiconductor package 100 with the first portion 114 and the second portion 115 as described above can prevent such a crack from occurring. Figure 1

[0040] The first portion 114 can protrude from the second portion 115 by any suitable height, as long as the above-described effects are obtained. For example, the first portion 114 can protrude by about 50 pm or more, or about 100 pm or more, or about 150 pm or more, or about 300 pm or more, or about 500 pm or more.

[0041] Figure 3A A perspective view of a semiconductor package 300 is shown, which can be similar or identical to the semiconductor package 100 except for the differences described below. Note that in the example of FIG. 5, the first portion 114 is not present.​​Figure 3A In particular, the semiconductor package 300 is shown with the second side 112 of the molding body 110 facing upwards and the first side 111 facing downwards.

[0042] The semiconductor package 300 can for example be configured to be connected to a substrate, like a heat spreader or a substrate, via a sinter joint. To manufacture such a joint, a sinter material 310 is deposited on the exposed portions of the one or more die carriers 130 exposed from the second side 112 of the molding body 110. Note that in Figure 3A In the example shown, the semiconductor package 300 comprises four exposed portions of the one or more die carriers 130 arranged in a matrix. Figure 3A The four exposed portions shown in Fig. 2 have the same shape and the same size. However, the exposed portions can also have different shapes and / or different sizes.

[0043] The semiconductor package 300 can comprise an external contact 320 arranged at one of the side edges 113 of the molding body 110. The semiconductor package 300 can comprise further external contacts 320 which can for example be arranged at the same side edge 113 as the external contact 320 and / or at an opposite side edge 113. The further external contacts 320 can for example be exposed from the second portion 115 of the first side 111 (compare Figure 3B and Figure 3C ).

[0044] When viewed from above the second side 112 of the molding body 110, the semiconductor package 300 can have an asymmetric structure. This can mean that the exposed portions of the one or more die carriers 130 and thus the deposits of sinter material 310 are not centered on the second side 112 (in Figure 3A In Fig. 2, the exposed portions and thus the deposits of sinter material 310 are arranged closer to the left edge of the second side 112 than to the right edge. For this reason, the press 200 can exert a pressure on the entire first side 111 during the sintering process if the first side 111 does not comprise a protruding first portion 114 aligned with the deposits of sinter material 310 (compare Figure 2 In this case, the sinter material 310 will be pressed downwards more strongly at one edge of the first side 111 than at the opposite edge of the first side 111.

[0045] Figure 3B A cross-sectional view of the semiconductor package 300 is shown. As Figure 3BAs shown, the first portion 114 of the first side 111 is perpendicularly aligned with the exposed portion of the die carrier 130, and therefore also perpendicularly aligned with the deposit of the sintered material 310. This could mean that the center point of the first side 111 and the common center point of the exposed portion of the die carrier 130 are both arranged along the vertical line z. Furthermore, the exposed portion of the die carrier 130 can, for example, be arranged inside the periphery of the first portion 114 (compare...). Figure 3B According to another example, it is the exact opposite.

[0046] Figure 3C A cross-sectional view of a semiconductor package 300 according to another example is shown, which, apart from the differences described below, is similar to... Figure 3B The examples shown are similar or identical. Specifically, in Figure 3C In the example shown, the first side 111 includes a plurality of first portions 114 that are perpendicularly aligned with a plurality of exposed portions of the die carrier 130. For example, there may be first portions 114 aligned with each individual exposed portion of the die carrier 130, or two or more exposed portions may be aligned with a common first portion 114.

[0047] Because the second part 115, rather than the first part 114, is arranged vertically above a specific portion of the second side 112 that does not include any exposed portion of the die carrier 130, the press 200 does not tilt the semiconductor package 300 and can produce sintered joints of uniform thickness.

[0048] Figure 4A A cross-sectional view of a power electronic system 400 is shown. The power electronic system 400 includes a semiconductor package 410 mounted on a substrate 420. The semiconductor package 410 may be similar to or identical to semiconductor packages 100 or 300. The substrate 420 may be, for example, a heat sink and / or a substrate. The semiconductor package 410 is disposed on the substrate 420 such that a second side 112 of the molded body 110 faces the substrate 420. Figure 4A In the example shown, the first side 111 of the molded body 110 includes a plurality of first portions 114. However, the first side 111 may of course also include only a single first portion 114.

[0049] Semiconductor package 410 is mechanically coupled to substrate 420 by applying pressure to one or more first portions 114 of a first side 111 of molded body 110 via clamp 430. Clamp 430 may be, for example, a metal clamp and may be, for example, arranged at opposite sides of semiconductor package 410. Since semiconductor package 410 is mechanically secured to substrate 420 by clamp, it may not be necessary to further solder or sinter semiconductor package 410 to substrate 410.

[0050] According to one example, the power electronic system 400 comprises a rigid plate 440 connected between the clamp 430 and the semiconductor package 410. The rigid plate 440 can be configured to distribute the mechanical force applied by the clamp 430 onto the semiconductor package 410 over one or more first portions 114 of the first side 111 of the molding body 110. The rigid plate 440 can for example be a metal plate.

[0051] According to one example, the power electronic system 400 further comprises a resilient layer 450 arranged between the rigid plate 440 and the one or more first portions 114 of the first side 111 of the molding body 110. The resilient layer 450 can be configured to distribute the pressure evenly over the one or more first portions 114 and / or to compensate for height tolerances. The resilient layer 450 can comprise or consist of any suitable resilient material and can for example comprise or consist of a rubber pad. According to another example, the power electronic system 400 does not comprise the resilient layer 450, which means that the rigid plate 440 directly contacts the one or more first portions 114.

[0052] The power electronic system 400 can further comprise an electrically insulating layer 460 arranged between the semiconductor package 410 and the substrate 420 and configured to electrically insulate the semiconductor package 410 from the substrate 420.

[0053] Figure 4B A plan view of the power electronic system 400 is shown from above the rigid plate 440. As Figure 4B indicated, the clamp 430 can for example be arranged at two opposite side edges of the semiconductor package 410, and the remaining two side edges of the semiconductor package 410 can comprise external contacts 470.

[0054] The one or more first portions 114 of the first side 111 of the molding body 110 can for example be arranged at a non-zero distance from the edges of the first side 111. The reason for this arrangement can be that applying pressure on the edges can lead to severe warping of the semiconductor package 410, and such warping can potentially damage the semiconductor package 410. Therefore, the one or more first portions 114 can be arranged on the first side 111 at such locations that severe warping of the semiconductor package 410 can be avoided.

[0055] Figure 4C A power electronic system 400 according to another example is shown. In particular, in the example shown Figure 4C the clamp 430 is replaced by a screw 480. In the example shown Figure 4C a spring element 490 is arranged between the screw 480 and the rigid plate 440, wherein the spring element 490 is configured to apply pressure onto the rigid plate 440. According to another example, the screw 480 is directly connected to the rigid plate 440.

[0056] Figure 4D A power electronic system 400 according to yet another example is shown. In this example, the semiconductor package 410 is reversibly coupled to the substrate 420 using a clamp or a screw. Figures 4A to 4C On the other hand, in the example shown in FIG. 4, the semiconductor package 410 is sintered onto the substrate 420 via a sintering layer 492. As shown, the sintering layer 492 can be arranged within the perimeter of the first portion 114. Further, the space between the semiconductor package 410 and the substrate 420 below the second portion 115 can be free of the sintering layer 492. Figure 4D Figure 4D

[0057] Figure 5 is a flowchart of an exemplary method 500 for mechanically coupling a semiconductor package to a heat sink. The method 500 can for example be used for coupling one of the semiconductor packages 100, 300 and 410 to the substrate 200 or 420.

[0058] The method 500 comprises a process of providing a semiconductor package comprising a molded body comprising a first side and an opposite second side, at least one semiconductor die enclosed by the molded body, and a die carrier comprising a first side and an opposite second side, wherein the at least one semiconductor die is arranged on the first side of the die carrier, and wherein the second side of the die carrier is at least partially exposed from the second side of the molded body to form at least one exposed portion of the die carrier, wherein the first side of the molded body comprises a first portion and a second portion, wherein the first portion protrudes in a perpendicular direction from the second portion to form a flat surface, wherein the perpendicular direction is perpendicular to the first side of the molded body, wherein the second portion extends completely along at least one edge of the first side of the molded body, and wherein a center point of the first portion is vertically aligned with a center point of the exposed portion. The method 500 comprises a process of arranging the semiconductor package on the heat sink such that the second side of the semiconductor package faces the heat sink at 502, and a process of applying a pressure onto the first portion of the first side of the molded body but not onto the second portion of the first side of the molded body in order to mechanically and thermally couple the semiconductor package to the heat sink at 503.

[0059] According to one example of the method 500, coupling the semiconductor package to the heat sink comprises a sintering process. According to another example, coupling the semiconductor package to the heat sink comprises a clamping process or a screwing process.

[0060] Figure 6 ​​A cross-sectional view of semiconductor package 600 is shown, which can be similar or identical to semiconductor packages 100, 300, 410, except for the differences described below. Semiconductor package 600 is shown as having a recess 608 in the first portion 114 of the mold body 110. The first portion 114 has two separate islands, e.g., a first island 604 and a second island 606 separated from each other by the recess 608. The recess 608 can be formed by a protrusion in the molding tool or by cutting (e.g., laser cutting, etching). As one example, as shown, the semiconductor package 600 has two islands separated by one recess. However, the semiconductor package 600 can have more than two islands and more than one recess. The semiconductor package can also have external contacts, such as but not limited to press-fit pins 610, protruding from the recess 608. The contacts can be electrically coupled with the semiconductor die 120 directly or via the die carrier 130, e.g., the upper conductive layer 133. Figure 6

[0061] When using a sintering press to mount the semiconductor package 600 onto the substrate 420, it can be desirable to apply different pressures to different portions of the semiconductor package. For example, areas of the semiconductor package that have a substantial amount of rigid material, semiconductor die, or metal contacts, such as press-fit pins, can pass different pressures to the sintering press than the surrounding mold compound. Thus, the total maximum pressure applied by the sintering press can be limited by specific portions of the semiconductor package. The recess in the molded package can avoid some areas from being applied, but the total pressure limit will still exist. Figure 7 Another example of a connection process for the semiconductor package 600 with the substrate 420 is shown, where the pressure of the sintering press 702 can be further optimized. The semiconductor package 600 and the substrate 420 (e.g., a substrate or a cooler) are arranged in the sintering press 702. A sintering layer 491 (e.g., a sintering paste) is arranged between the exposed portions of the die carrier 130 and the substrate 420. The sintering press 702 has an upper section 702a facing the first portion 114 and a lower section 702b facing the substrate 420. The upper section 702a has a first independent section 704 and a second independent section 706 mounted on a head 708. The independent sections 704, 706 are separated from each other by a gap 710. The upper section 702a is arranged such that the first independent section 704 faces the first island 604, the second independent section 706 faces the second island 606, and the gap 710 faces the recess 608 of the first portion 114. The islands 604 and 606 can now be pressed by different forces applied by the upper section 702a of the sintering press 702, respectively. An O-ring 712 comprising an elastic material can be arranged between the head 708 and the first independent section 704, as shown. Figure 7 ​The O-ring 712 deforms and reduces the force exerted on the first island 604 compared to the second island 606 when the upper section 702a presses the first portion 114. In particular, the first independent section 704 is configured to press the first island 604 with a first force and the second independent section 706 is configured to press the second island 606 with a second force that can be different from the first force. Due to the O-ring 712 in the sintering press 702, the first force is smaller than the second force. Therefore, the pressure will be distributed unevenly over the exposed portion of the die carrier 130. Consequently, the sintering layer 491 will also experience an uneven pressure. The sintering layer 491 can have a thickness in the range of 15 pm to 500 pm, in particular 30 pm to 300 pm, which is measured perpendicularly between the exposed portion of the die carrier 130 and the substrate 420. Due to the few pm thickness of the sintering layer 491, the uneven pressure will result in a different porosity in the final sintering layer 492. In particular, since the first portion 493 of the sintering layer 491 under the first island 604 will experience a smaller pressure than the second portion 494 of the sintering layer 491 under the second island 606, the joints formed in the first portion 493 of the sintering layer 492 will have a higher porosity than the joints formed in the second portion 494 of the sintering layer 492. A higher porosity means that the particles, e.g. silver particles, in the first portion 493 of the joint are separated by a larger distance compared to the particles in the second portion 494 of the joint. The first portion 493 can have more voids compared to the second portion 494. The difference in porosity depends on the difference in pressure and can be in the range of 2% to 50%, in particular in the range of 5% to 30%. The non-uniform porosity of the joint increases the flexibility of the joint without changing the mechanical strength of the joint.

[0062] The pressing of the first portion 114 can be achieved by different methods. For example, the upper section 702a can be a chamber comprising a gas, e.g. nitrogen, for pressing. The gas can be distributed in the upper section 702a such that the upper section 702a presses the first island 604 with a first force and the second island 606 with a second force.

[0063] As mentioned above, the gap 710 of the sintering press 702 overlaps with the recess 608 of the first portion 114 and therefore the sintering press 702 does not exert any force on the recess 608. As Figure 6 As shown, in case of inserting a contact such as a press-fit pin into the recess, the semiconductor package 600 can be pressed onto the substrate 420 without damaging the press-fit pin 610 or the underlying die carrier 130.

[0064] In the following, the semiconductor package, the power electronic system and the method for mechanically coupling the semiconductor package to a heat sink are further explained using concrete examples.

[0065] Example 1 is a semiconductor package comprising: a molding body comprising a first side and an opposite second side; at least one semiconductor die encapsulated by the molding body; and a die carrier comprising a first side and an opposite second side, wherein the at least one semiconductor die is arranged on the first side of the die carrier, and wherein the second side of the die carrier is at least partially exposed from the second side of the molding body to form at least one exposed portion of the die carrier, wherein the first side of the molding body comprises a first portion and a second portion, wherein the first portion protrudes in a perpendicular direction from the second portion to form a flat surface, wherein the perpendicular direction is perpendicular to the first side of the molding body, wherein the second portion extends completely along at least one edge of the first side of the molding body, and wherein a center point of the first portion is vertically aligned with a center point of the exposed portion.

[0066] Example 2 is the semiconductor package of example 1, wherein the second portion extends completely along at least two opposite edges of the first side of the molding body.

[0067] Example 3 is the semiconductor package of example 1, wherein the second portion extends completely along all four edges of the first side of the molding body.

[0068] Example 4 is the semiconductor package of one of the preceding examples, wherein the first portion comprises a plurality of islands separated from each other by the second portion.

[0069] Example 5 is the semiconductor package of examples 1 to 3, wherein the first portion has a recess.

[0070] Example 6 is the semiconductor package of example 5, further comprising a press-fit pin protruding from the recess.

[0071] Example 7 is the semiconductor package of one of the preceding examples, wherein the first portion is arranged inside a periphery of the at least one exposed portion of the die carrier, and wherein the second portion is at least partially arranged outside the periphery of the at least one exposed portion.

[0072] Example 8 is the semiconductor package of example 7, wherein at least 50% of the second portion is arranged outside the periphery.

[0073] Example 9 is the semiconductor package of one of the preceding examples, further comprising: a power contact electrically connected to a power terminal of the at least one power semiconductor die, wherein the power contact is exposed from the second portion of the first side of the molding body.

[0074] Example 10 is the semiconductor package of one of the preceding examples, wherein the die carrier comprises or consists of a leadframe or a substrate, the leadframe or the substrate comprising two electrically conductive layers separated by an electrically insulating layer.

[0075] Example 11 is the semiconductor package of Example 10, wherein the die carrier comprises two metal layers separated by a ceramic layer, wherein a protruding portion of the ceramic layer protrudes laterally from the metal layers, the lateral direction being parallel to the first and second sides of the die carrier, and wherein the portion of the first side of the molded body vertically above the protruding portion consists of the second portion.

[0076] Example 12 is a power electronic system comprising the semiconductor package according to one of the preceding claims and a heat sink, wherein the semiconductor package is mechanically coupled to the heat sink such that the second side of the semiconductor package faces the heat sink.

[0077] Example 13 is the power electronic system of Example 12, wherein the second side of the die carrier is connected to the heat sink by a sintering layer.

[0078] Example 14 is the power electronic system of Example 13, wherein the sintering layer is arranged within the perimeter of the first portion.

[0079] Example 15 is the power electronic system of Example 13 or 14, wherein the space vertically below the second portion is free of the sintering layer.

[0080] Example 16 is the power electronic system of Example 14, wherein the semiconductor package is mechanically coupled to the heat sink by a clamp or a screw applying pressure onto the first portion of the first side of the molded body.

[0081] Example 17 is the power electronic system of Example 16, further comprising a rigid plate connected between the clamp or the screw and the semiconductor package, and an elastic layer arranged between the rigid plate and the first portion of the first side of the molded body and configured to distribute the pressure evenly along the first portion.

[0082] Example 18 is a method for mechanically coupling a semiconductor package to a heat spreader, the method comprising: providing a semiconductor package comprising: a mold body comprising a first side and an opposite second side; at least one semiconductor die encapsulated by the mold body; and a die carrier comprising a first side and an opposite second side, wherein the at least one semiconductor die is arranged on the first side of the die carrier, and wherein the second side of the die carrier is at least partially exposed from the second side of the mold body to form at least one exposed portion of the die carrier, wherein the first side of the mold body comprises a first portion and a second portion, wherein the first portion protrudes in a perpendicular direction from the second portion to form a flat surface, wherein the perpendicular direction is perpendicular to the first side of the mold body, wherein the second portion extends completely along at least one edge of the first side of the mold body, and wherein a center point of the first portion is vertically aligned with a center point of the exposed portion; arranging the semiconductor package on a heat spreader such that the second side of the semiconductor package faces the heat spreader; and applying pressure onto the first portion of the first side of the mold body but not onto the second portion of the first side of the mold body in order to mechanically and thermally couple the semiconductor package to the heat spreader.

[0083] Example 19 is the method of example 18, wherein coupling the semiconductor package to the heat spreader comprises a sintering process.

[0084] Example 20 is the method of example 19, further comprising: forming a recess in the first portion to form a first island and a second island separate from each other, and wherein applying pressure onto the first portion comprises pressing the first portion by a press comprising two independent sections, wherein a first independent section of the press presses onto the first island of the first portion with a first force and a second independent section of the press presses onto the second island of the first portion with a second force.

[0085] Example 21 is the method of example 20, wherein the first force is different from the second force.

[0086] Example 22 is the method of example 18, wherein coupling the semiconductor package to the heat spreader comprises a clamping process or a screwing process.

[0087] Example 23 is an apparatus comprising means for performing the method according to any one of examples 18 to 22.

[0088] While specific examples have been shown and described herein, those skilled in the art will understand that various substitutions and / or alterations can be made to the specific examples shown and described without departing from the scope of the present application. The application is intended to cover any adaptations or variations of the specific examples discussed herein. Therefore, the application is intended to only be limited by the claims and their equivalents.

[0089] It should be noted that the methods and devices outlined in this document, including the preferred embodiments of the methods and devices, can be used independently or in combination with other methods and devices disclosed in this document. Furthermore, features outlined in the context of a device can also apply to a corresponding method, and vice versa. Moreover, all aspects of the methods and devices outlined in this document can be combined in any combination. In particular, features of the claims can be combined in any manner with each other.

[0090] It should be noted that the description and drawings only illustrate the principles of the proposed method and system. A person skilled in the art will be able to implement various arrangements, although these arrangements are not explicitly described or shown herein, which embody the principles of the application and which are included in its spirit and scope. Furthermore, all examples and embodiments outlined in this document are primarily explicitly intended for explanatory purposes only, to help the reader understand the principles of the proposed method and system. Moreover, all statements herein for providing principles, aspects and embodiments of the application, as well as specific examples thereof, are intended to encompass their equivalents.

Claims

1. A semiconductor package (100), comprising: a molding body (110) comprising a first side (111) and an opposite second side (112), at least one semiconductor die (120) encapsulated by the molding body (110), and a die carrier (130) comprising a first side (131) and an opposite second side (132), wherein the at least one semiconductor die (120) is arranged on the first side (131) of the die carrier (130), and wherein the second side (132) of the die carrier (130) is at least partially exposed from the second side (112) of the molding body (110) to form at least one exposed portion of the die carrier (130), wherein the first side (111) of the molding body (110) comprises a first portion (114) and a second portion (115), wherein the first portion (114) protrudes in a perpendicular direction from the second portion (115) to form a flat surface, wherein the perpendicular direction is perpendicular to the first side (111) of the molding body (110), wherein the second portion (115) extends completely along at least one edge of the first side (111) of the molding body (110), and wherein a center point of the first portion (114) is vertically aligned with a center point of the exposed portion.

2. The semiconductor package (100) according to claim 1, wherein The second portion (115) extends completely along at least two opposite edges of the first side (111) of the molding body (110).

3. The semiconductor package (100) of claim 1, wherein, The second portion (115) extends completely along all four edges of the first side (111) of the molding body (110).

4. The semiconductor package (100) according to one of the preceding claims, wherein The first portion (114) comprises a plurality of islands separated from each other by the second portion (115).

5. The semiconductor package (100) according to one of claims 1 to 3, wherein The first portion (114) has a recess.

6. The semiconductor package according to claim 5, further comprising a press-fit pin protruding from the recess.

7. The semiconductor package (100) according to one of the preceding claims, wherein The first portion (114) is arranged inside a periphery of the at least one exposed portion of the die carrier (130), and wherein the second portion (115) is at least partially arranged outside the periphery of the at least one exposed portion.

8. The semiconductor package (100) of claim 5, wherein, At least 50% of the second portion (115) is arranged outside the periphery.

9. The semiconductor package (300) according to one of the preceding claims, further comprising: a power contact (320) electrically connected to a power terminal of the at least one power semiconductor die (120), wherein the power contact (320) is exposed from the second portion (115) of the first side (111) of the molding body (110).

10. The semiconductor package (100) according to one of the preceding claims, wherein The die carrier (130) comprises or consists of a leadframe or a substrate comprising two electrically conductive layers (133, 134) separated by an electrically insulating layer (135).

11. The semiconductor package (100) of claim 8, wherein, The die carrier (130) comprises two metal layers separated by a ceramic layer, wherein a protruding portion of the ceramic layer protrudes laterally from the metal layers, the lateral direction being parallel to the first side (131) and the second side (132) of the die carrier (130), and wherein a portion of the first side (111) of the molding body (110) vertically above the protruding portion consists of the second portion (115).

12. A power electronic system (400) comprising: a semiconductor package (410) according to one of the preceding claims, and a heat sink (420), wherein the semiconductor package (410) is mechanically coupled to the heat sink (420) such that the second side of the semiconductor package (410) faces the heat sink (420).

13. The power electronic system (400) of claim 12, wherein, The second side (132) of the die carrier (130) is connected to the heat sink (420) by a sinter layer (492).

14. The power electronic system (400) of claim 13, wherein, The sinter layer (492) is arranged within a perimeter of the first portion (114).

15. The power electronic system (400) according to claim 13 or 14, wherein A space vertically below the second portion (115) is free of the sinter layer (492).

16. The power electronic system (400) of claim 12, wherein, The semiconductor package (410) is mechanically coupled to the heat sink (420) by a clamp (430) or a screw (480) exerting pressure onto the first portion (114) of the first side (111) of the molding body (110).

17. The power electronic system (400) according to claim 16, further comprising: a rigid plate (440) connected between the clamp (430) or screw (480) and the semiconductor package (410), and a resilient layer (450) arranged between the rigid plate (440) and the first portion (114) of the first side (111) of the molding body (110) and configured to distribute pressure evenly along the first portion (114).

18. A method (500) for mechanically coupling a semiconductor package to a heat sink, comprising: providing (501) a semiconductor package, the semiconductor package comprising: a molding body comprising a first side and an opposite second side, at least one semiconductor die encapsulated by the molding body, and a die carrier comprising a first side and an opposite second side, wherein the at least one semiconductor die is arranged on the first side of the die carrier, and wherein the second side of the die carrier is at least partially exposed from the second side of the molding body to form at least one exposed portion of the die carrier, wherein the first side of the molding body comprises a first portion and a second portion, wherein the first portion protrudes in a vertical direction from the second portion to form a flat surface, wherein the vertical direction is perpendicular to the first side of the molding body, wherein the second portion extends completely along at least one edge of the first side of the molding body, and Wherein, the center point of the first part is perpendicularly aligned with the center point of the exposed part; The semiconductor package is arranged (502) on a heat sink such that the second side of the semiconductor package faces the heat sink; and Pressure (503) is applied to the first portion of the first side of the molded body but not to the second portion of the first side of the molded body in order to mechanically and thermally couple the semiconductor package to the heat sink.

19. The method (500) of claim 18, wherein Coupling the semiconductor package to the heat sink includes a sintering process.

20. The method of claim 19, further comprising: A recess is formed in the first portion to form a first island and a second island that are separated from each other; and Applying pressure (503) to the first part includes pressing the first part by a press comprising two independent sections, wherein the first independent section of the press presses the first island of the first part with a first force, and the second independent section of the press presses the second island of the first part with a second force.

21. The method of claim 20, wherein, The first force is different from the second force.

22. The method (500) of claim 18, wherein Coupling the semiconductor package to the heat sink includes a clamping process or a screwing process.

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