Method for manufacturing a semiconductor package using a plurality of air outlets or channels arranged above a power line

Abstract

Various aspects relate to a method of manufacturing a semiconductor package, the method comprising: providing a lead frame comprising a die pad and a first power line, the first power line comprising a first side and an opposite second side; disposing at least one power semiconductor die on the die pad and electrically connecting the power semiconductor die to the first power line; disposing the lead frame in a cavity of a mold such that the first power line extends out of the cavity at a first lateral wall of the cavity;Providing an air outlet in the first lateral wall of the cavity, directly above the first side of the first power line, such that the first side of the first power line forms a sidewall of the air outlet; providing a plurality of air outlets in the first sidewall of the cavity directly above the first side of the first power line, such that the first side of the first power line forms a sidewall of the plurality of air outlets; and / or wherein the method comprises providing a plurality of channels in the first side of the first power line, the plurality of channels configured to act as air outlets for the cavity; and filling the cavity with liquid molding material to form a molded body encapsulating the power semiconductor die, the plurality of air outlets allowing gas displaced from the cavity by the liquid molding material to exit the cavity.

Description

TECHNICAL FIELDThe present disclosure relates to a method of manufacturing a semiconductor package, the method comprising using an air outlet or duct disposed over a power line to allow gas in a cavity of a mold to exit the cavity.BACKGROUNDForming a semiconductor package may include molding over a semiconductor chip and a lead frame to form a molded body. The molded body may be configured to protect the semiconductor chip from environmental hazards. In order to produce the molded body, liquid molding material can be filled into a cavity of a molding tool, wherein the semiconductor chip and the lead frame are arranged in the cavity. A cavity of a mold may include an inlet for the liquid mold material and an outlet for excess liquid mold material. It is desirable that the liquid molding material completely fills the cavity so that no gas bubbles remain in the cavity. Remaining gas bubbles may cause voids in the molded body when the molding material has been cured. Such gaps in the molded body may impair the mechanical and / or electrical properties of the semiconductor package. KR 10 1999 027 160 A, JP 2006-229 243 A or also JP H09-181 243 A discloses providing further air outlets on the mold body edges in addition to the mold material outlet in order to avoid the inclusion of gas and to prevent gaps in the mold body. Improved methods of manufacturing a semiconductor package may help reduce or even eliminate the formation of such voids, and may also provide other advantages.SUMMARYVarious aspects relate to a method of manufacturing a semiconductor package, the method comprising: providing a leadframe comprising a die pad and a first power line, the first power line comprising a first side and an opposing second side; arranging at least one power semiconductor die on the die pad and electrically connecting the power semiconductor die to the first power line; arranging the leadframe in a cavity of a mold tool such that the first power line extends out of the cavity at a first lateral wall of the cavity; providing an air outlet in the first lateral wall of the cavity directly above the first side of the first power line such that the first side of the first power line forms a sidewall of the air outlet, providing a plurality of air outlets in the first sidewall of the cavity directly above the first side of the first power line such that the first side of the first power line forms a sidewall of the plurality of air outlets, and / or wherein the method comprises providing a plurality of channels in the first side of the first power line, wherein the plurality of channels is configured to act as air outlets for the cavity; Filling the cavity with liquid molding material to form a mold body encapsulating the power semiconductor die, wherein the plurality of air outlets allow gas displaced from the cavity by the liquid molding material to exit the cavity.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 THE DRAWINGSThe present disclosure is illustrated by way of example and not limitation in the figures of the accompanying drawings, in which like reference numerals refer to similar or identical elements. The elements of the drawings are not necessarily to scale relative to each other. The features of the various illustrated examples may be combined unless they are mutually exclusive. FIGS. 1A to 1G illustrate a semiconductor package at various stages of manufacturing according to an example method of manufacturing a semiconductor package. The method uses a mold tool comprising an air outlet disposed directly above a power line of the semiconductor package. FIGS. 2A to 2D illustrate another semiconductor package at various stages of manufacturing according to another example method of manufacturing a semiconductor package. The method comprises arranging a channel in a first side of a power line of the semiconductor package, wherein the channel acts as an air outlet during a molding process. FIG. 3 illustrates a semiconductor package disposed in a cavity of a mold, the cavity including an inlet and an outlet for liquid molding material. FIG. 4 is a flow diagram of an example method of manufacturing a semiconductor package, the method comprising providing an air outlet or channel configured to act as an air outlet during a molding process.DETAILED DESCRIPTIONIn the following detailed description, well-known structures and elements are shown in schematic form to facilitate describing one or more aspects of the disclosure. In this regard, directional terminology such as "top", "bottom", "left", "right", "top", "bottom", etc. is used with reference to the orientation of the figure(s) described. Since components of the disclosure may be positioned in a number of different orientations, the directional terminology is used for illustrative purposes only. It should be understood that other examples may be used and structural or logical changes may be made.Moreover, while a particular feature or aspect of an example may be disclosed with respect to only one of several implementations, such feature or aspect may be combined with one or more other features or aspects of the other implementations as may be desired and advantageous for a given or particular application, unless expressly stated otherwise or not technically limited. Furthermore, to the extent that the terms "include," "have," "with," or other variants thereof are used in either the detailed description or the claims, such terms are intended to be inclusive in a manner similar to the term "comprise.". The terms "coupled" and "connected" may be used together with derivatives thereof. It will be understood that these terms may be used to indicate that two elements cooperate or interact regardless of whether they are in direct physical or electrical contact or not in direct contact with each other; intervening elements or layers may be provided between the "bonded", "attached", or "connected" elements. However, it is also possible for the "bonded", "attached" or "connected" elements to be in direct contact with one another. Moreover, the term "exemplary" is intended to be merely an example and not the best or optimum.The examples of a semiconductor package and the method for manufacturing a semiconductor package described below may use various kinds of semiconductor chips or circuits integrated into the semiconductor chips, including AC / DC or DC / DC converter circuits, inverter circuits, power MOS transistors, power Schottky diodes, JFETs (Junction Gate Field Effect Transistors), power bipolar transistors, power integrated circuits, etc. The examples may also use semiconductor chips including MOS transistor structures or vertical transistor structures, such as IGBT structures (Insulated Gate Bipolar Transistors) or generally transistor structures, wherein at least one electrical contact pad is arranged on a first main side of the semiconductor chip and at least one other electrical contact pad is arranged on a second main side of the semiconductor chip opposite the first main side of the semiconductor chip.The semiconductor chip(s) may / may be made of a specific semiconductor material, for example Si, SiC, SiGe, GaAs, GaN, or any other semiconductor material, and may further include one or more of inorganic and organic materials other than semiconductors, such as insulators, plastics or metals.An efficient method of manufacturing a semiconductor package as well as an efficient semiconductor package may reduce material consumption, ohmic losses, chemical waste, etc., and thus may allow energy and / or resource savings. Improved methods for manufacturing a semiconductor package and improved semiconductor packages as indicated in this description may thus contribute at least indirectly to green technology solutions, i.e. climate friendly solutions providing attenuation of energy and / or resource usage.FIGS. 1A to 1G show a semiconductor package 100 at various stages of manufacturing according to an example method of manufacturing a semiconductor package. The semiconductor package 100 may be, for example, a power semiconductor package configured to operate at a high current of, for example, 1 A or more or 10 A or more or 50 A or more or 100 A or more or even 500 A or more. The semiconductor package 100 may additionally or alternatively be configured to operate at voltages of, for example, 100 V or more, or 250 V or more, or 500 V or more, or 600 V or more, or 1.2 kV or more, or even 2 kV or more. The semiconductor package 100 may be, for example, a surface mount device (SMD) or, according to another example, a via device (THD).As shown in FIG. 1A, a lead frame 110 is provided. The leadframe 110 may comprise or consist of any suitable metal or metal alloy. For example, the lead frame 110 may include or consist of Al or Cu. Note that the specific configuration of the lead frame 110 shown in the figures is only an example, and any other suitable configuration may be used.The leadframe 110 includes a die pad 112 and a first power line 114. Further, the first power line 114 includes a first side 114_ 1 and an opposing second side 114_ 2 (see FIG. 1C ). The die pad 112 may also include a first side 112_ 1 and an opposing second side 112_ 2, wherein the first sides 112_ 1, 114_ 1 and the second sides 112_ 1, 114_ 2 of the die pad 112 and the first power line 114 have the same respective orientations.According to an example, the leadframe 110 may include one or more additional leads and / or one or more additional die pads. For example, the leadframe 110 may include a second power line 116 and / or one or more control lines 118. For example, the first power line 114 may be configured to be electrically connected to a first power terminal of a power semiconductor die (e.g., a source, drain, emitter, or collector terminal), and the second power line 116 may be configured to be connected to a second power terminal of the power semiconductor die. In other words, the first power line 114 and one or more optional additional power lines of the leadframe 110 may be configured to act as power contacts of the semiconductor package 100 carrying a load current. For example, the control line(s) 118 may be configured to be connected to a gate terminal of the semiconductor chip and / or the control line(s) 118 may be configured to transmit sensing signals, e.g., for temperature sensing, voltage sensing, etc.As shown in FIG. 1B, at least one power semiconductor die 120 is disposed over the die pad 112, for example over the first side 112_ 1 of the die pad 112. This may include, for example, soldering or sintering or bonding the power semiconductor die 120 to the die pad 112 with conductive adhesive. Further, the power semiconductor die 120 is electrically connected to the first power line 114. According to the example shown in FIG. 1B, the first power line 114 and the die pad 112 are monolithically formed, and therefore, the power semiconductor die 120 is connected to the first power line 114 when the power semiconductor die 120 is connected to the die pad 112. According to another example, the first power line 114 and the die pad 112 are not monolithically formed, similar to the die pad 112 and the second power line 116. In this case, connecting the power semiconductor die 120 to the first power line 114 may include using an electrical connector such as a bond wire, a ribbon, or a terminal to connect the power semiconductor die 120 to the first power line 114. The power semiconductor die 120 may further be electrically connected to the second power line 116.According to an example, the semiconductor package 100 comprises more than one power semiconductor die 120, for example two, four, six, etc. power semiconductor dies 120. The more than one power semiconductor dies 120 may all be the same type of die or the power semiconductor dies 120 may be different types of dies. The more than one power semiconductor dies 120 may be electrically connected to form any suitable type of electrical circuit within the semiconductor package 100, for example, a half bridge circuit, a full bridge circuit, a converter circuit, an inverter circuit, etc. All individual semiconductor dies 120 may be disposed on individual die pads 112 of the leadframe 110, or at least two of the semiconductor dies 120 may be disposed on a common die pad 112.As shown in FIG. 1C, the leadframe 110 is arranged in a cavity 132 of a mold 130, such that the first power line 114 extends out of the cavity 132 at a first sidewall 134 of the cavity 132. The cavity 132 is configured to be filled with liquid molding material to produce a molded body of the semiconductor package 100, the molded body encapsulating the power semiconductor die 120. Note that FIG. 1C corresponds to a sectional view taken along line C-C' in FIG. 1B.The mold 130 may include, for example, an upper half 136 and a lower half 138, wherein the cavity 132 is provided by clamping the leadframe 110 between the upper and lower halves 136, 138 of the mold 130.According to an example, the mold 130 may include an inlet configured to fill liquid mold material into the cavity 132 (not shown in FIG. 1C ). According to one example, the mold 130 may include an outlet configured to allow excess liquid mold material to exit the cavity 132 (also not shown in FIG. 1C ). The inlet may be disposed on a second sidewall of the cavity 132, for example, the second sidewall opposing the first sidewall 134. The outlet may be arranged, for example, opposite the inlet, for example, on the first side wall 134.The mold 130 includes an air outlet 140 in the first sidewall 134 of the cavity 132. The air outlet 140 is located directly above the first side 114_ 1 of the first power line 114 such that the first side 114_ 1 of the first power line 114 forms a sidewall of the air outlet 140 (in particular, the first side 114_ 1 may form the bottom sidewall of the air outlet 140). The air outlet 140 extends from the cavity 132 to the outside of the mold 130. The air outlet 140 is configured to allow gas in the cavity 132 to exit the mold 130.FIG. 1D shows a side view of the mold 130 along arrow D in FIG. 1C. In particular, FIG. 1D shows the air outlet 140 in more detail according to a specific example. As shown, the air outlet 140 is arranged directly above the first side 114_ 1 of the first power line 114. According to an example, the mold 130 may include a further air outlet 142 arranged directly above a first side of the second power line 116 (such that the first side of the second power line 116 forms a sidewall of the further air outlet 142). According to an example, the mold 130 includes an air outlet directly above each power line disposed along the first sidewall 134 of the cavity 132.As shown in FIG. 1D, the air outlet 140 may have a substantially rectangular cross-section. However, it is also possible for the air outlet to have, for example, a square cross section, a semicircular cross section, etc. In any case, however, the first side 114_ 1 of the first power line forms a side wall of the air outlet 140. In the case that the forming tool 130 comprises more than one air outlet (e.g. the air outlet 140 and the further air outlet 142), the individual air outlets can all have identical cross sections and / or identical dimensions or the individual air outlets can have different cross sections and / or different dimensions.The air outlet 140 (and possibly the air outlet 142) may have a width in the range of about 0.5 mm to about 5 mm, for example, wherein the width is measured parallel to the first side 114_ 1 of the first power line 114. The lower limit of this range may also be about 0.8 mm or about 1 mm, and the upper limit may also be about 4 mm or about 3 mm or about 2 mm or about 1.5 mm. The air outlet 140 (and possibly the air outlet 142) may have a height of about 10 μm to about 100 μm, for example, wherein the height is measured perpendicular to the first side 114_ 1 of the first power line 114. The lower limit of this range may also be about 20 μm or about 35 μm, and the upper limit may also be about 80 μm or about 50 μm.In the example shown in FIG. 1D, the mold 130 includes a single air outlet 140 disposed directly above the first power line 114 and a single further air outlet 142 disposed directly above the second power line 116. According to another example, the forming tool 130 comprises at least two air outlets 140, for example three air outlets 140, which are arranged next to each other directly above the first side 114_ 1 of the first power line 114. The forming tool 130 may also comprise at least two further air outlets 142, for example three further air outlets 142, which are arranged next to one another directly above the first side of the second power line 116.As shown in FIG. 1E, the cavity 132 is filled with liquid molding material 150 to produce a molded body encapsulating the power semiconductor die 120. The air outlet 140 (or air outlets 140, 142) allows (allow) gas displaced by the liquid molding material 150 to exit the cavity 132. Note that the gas displaced from the cavity 132 through the air outlet 140 is indicated by an arrow in FIG. 1E. The gas filling the cavity may be, for example, air, nitrogen, or any other suitable process gas.According to an example, the at least one power semiconductor die 120 is electrically connected to the first power line 114 and / or to the second power line 116 using one or more bond wires or one or more straps or a contact clamp. Upon filling the cavity 132, the liquid molding material 150 may flow past the one or more bond wires or straps or contact clip and past the at least one power semiconductor die 120 before reaching the air outlet 140. According to the example shown in FIGS. 1A-1G, the air outlet 140 and the semiconductor die 120 are both arranged over the same side of the leadframe 110 (i.e., over the first sides 112_ 1, 114_ 1 of the die pad 112 and the power line 114). The reason for this may be that gas bubbles could accumulate in the cavity 132 above that side of the leadframe 110 if the air outlet 140 were not present.For example, allowing the gas in the cavity 132 to exit the cavity 132 when the liquid molding material 150 is filled into the cavity 132 may prevent the formation of cavities in the molded body. Inspection of semiconductor packages fabricated without the use of the air outlets disclosed herein, as well as computer simulations, confirmed that voids may form predominantly directly over the first sides of the power lines 114, 116. This may be the case in particular if the inlet of the forming tool 130 is arranged on a side wall of the cavity 1323 which is opposite the power lines 114, 116. Further, it has been found that an air outlet or other type of outlet of the cavity 132 that is not disposed directly above the first sides of the power lines 114, 116, e.g., laterally adjacent to the power lines 114, 116, may not prevent the formation of cavities. In other words, gas may remain enclosed in the cavity 132, even in the event that an outlet is provided that is laterally adjacent to the power lines 114, 116. Gas may be predominantly enclosed directly over the first sides of the power lines 114, 116, and therefore it may be necessary for an air outlet to be arranged directly over the first sides in order to remove the gas from the cavity 132 (in other words, the first sides of the power lines 114, 116 may need to be a sidewall of the air outlets for the air outlets to function as intended).As shown in FIG. 1F, the liquid molding material 150 is cured to form a molded body 160, and the semiconductor package 100 is removed from the molding die 130. In the example shown in FIG. 1F, the mold body 160 includes a mold flash 162 at the position of the air outlet 140 since liquid molding material 150 at least partially fills the air outlet 140. According to another example, the air outlet 140 is so small and / or the liquid molding material 150 is so viscous that no liquid molding material 150 flows into the air outlet 140 and no molding flash 162 is formed.In the case that the molding burr 162 is formed, the method disclosed herein may optionally include a process for removing the molding burr 162 from the molded body 160. This removal process may include, for example, a chemical deburring process and / or a physical deburring process. A chemical deburring process may include, for example, using a suitable solvent to remove the mold flash 162, and a physical removal process may include, for example, using an air jet or a water jet to remove the mold flash 162. The removal process may be performed, for example, before the mold 160 is fully cured or, according to another example, after the mold 160 is fully cured.FIG. 1G shows the semiconductor package 100 after the molding burr 162 is removed (in the case where a molding burr is formed). Due to the air outlet 140 (and optionally the further air outlet 142), the molded body 160 can be substantially free of cavities or at least free of cavities on a large scale.FIGS. 2A to 2D show a further semiconductor package 200 at different stages of the production according to a further method for producing a semiconductor package. The semiconductor package 200 may be similar or identical to the semiconductor package 100 except for the differences described below. Further, the method disclosed with respect to FIGS. 2A-2D may be similar or identical to the method disclosed with respect to FIGS. 1A-1G, except for the differences described below.As shown in FIG. 2A, a lead frame 210 is provided, which may be similar or identical to the lead frame 110. However, the leadframe 210 includes a channel 212 in the first side 114_ 1 of the first power line 114. The channel 212 is configured to act as an air outlet similar to the air outlet 140 described above when the leadframe 210 is placed in a cavity of a mold. According to an example, the leadframe 210 includes one or more additional power lines, e.g. the second power line 116, arranged laterally next to the first power line 114, and the one or more additional power lines may also include channels (in the example shown in FIG. 2A, the second power line 116 includes a further channel 214). The one or more further channels may be similar or identical to channel 212.FIG. 2B shows a sectional view of the lead frame 210 along the line B-B' in FIG. 2A. For example, as shown in FIG. 2B, the channels 212, 214 may have a substantially rectangular cross-section. According to another example, the channels 212, 214 have a square cross-section, or a semi-circular cross-section, or any other suitable cross-section.The cross-section of the channels 212, 214 may have any suitable width and height. For example, the width and height of the channels 212, 214 may be equal to the width and height of the air outlets 140, 142 (see above). In particular, the dimensions of the channels 212, 214 may be small compared to the dimensions of the power lines 114, 116. At least for this reason, the channels 212, 214 do not impair the electrical and / or mechanical functionality of the power lines 114, 116.The channels 212, 214 may be fabricated using any suitable process. For example, the leadframe 210 may be subjected to a stamping process and / or an etching process and / or a laser ablation process to form the channels 212, 214. The formation of the channels 212, 214 may be performed, for example, during the same stamping process as the formation of the die pad 112 and the power lines 114, 116.The first power line 114 may include lateral sides 114_ 3 connecting the first and second sides 114_ 1, 114_ 2. According to an example, a width of the first power line 114 is in the range of 5 mm to 20 mm, wherein the width between opposite lateral sides 114_ 3 is measured. The lower limit of this range may also be about 6 mm or about 8 mm or about 10 mm, and the upper limit may also be about 18 mm or about 16 mm or about 14 mm or about 12 mm.According to an example, the channel 212 is arranged centrally between the opposite lateral sides 114_ 3. According to an example, the first page 114_ 1 may include a plurality of channels 212. The channels 212 of the plurality of channels 212 may be laterally adjacent to each other and centrally arranged between the lateral sides 114_ 3 of the first power line 114, for example. In the same way, it is of course also possible for the second power line 116 to comprise a multiplicity of further channels 214.According to the examples shown in FIGS. 1D and 2B, air outlets 140, 142 and channels 212, 214, respectively, are arranged over and in the first sides of the power lines 114, 116, respectively, and no air outlets or channels are arranged over and in the opposite second sides of the power lines 114, 116, respectively. According to another example, air outlets 140, 142 and / or ducts 212, 214 are arranged over and in both the first side and the second side of at least one of the power lines 114, 116.FIG. 2C shows a top view of the lead frame 210 arranged in a cavity of a mold 220. Note that the mold 220 is transparent in FIG. 2C to show the inside of the cavity 132. It is further noted that the power semiconductor die 120 is disposed over the leadframe 210 before the insertion of the leadframe 210 into the mold 220 (see FIG. 1B ).The channels 212, 214 extend between the cavity of the mold 220 and the exterior of the mold and may therefore act as air outlets that allow gas in the cavity to exit the cavity when liquid mold material is filled into the cavity. Because the power lines 114, 116 of the leadframe 210 include the channels 212, 214, a sidewall of the cavity of the mold 220 need not include the air outlets 140, 142, as does the first sidewall 134 of the mold 130.FIG. 2D shows the semiconductor package 200 after the mold body 160 is formed by molding over the leadframe 210 and the power semiconductor die 120, as disclosed above with respect to the semiconductor package 100. As shown in FIG. 2D, mold burrs 162 may form in the channels 212, 214 during the manufacture of the molded body 160. The mold ridges 162 may be removed as described with respect to the semiconductor package 100.The molded body 160 may include four lateral sides 164, wherein the first power line 114 and possibly also the second power line 116 are arranged at a first of the lateral sides 164. According to an example, some or all of the lateral sides 164 have edge lengths of about 1 cm or more, or about 1.4 cm or more, or about 2.1 cm or more, or about 4 cm or more, or about 5.5 cm or more, or about 7 cm or more. The molded body 160 may have, for example, a substantially square shape or a substantially rectangular shape when viewed from above a first side 161 of the molded body (see FIG. 2D ). Further, the molded body 160 may have any suitable thickness, wherein the thickness is measured between the first side 161 and an opposing second side. The thickness may be, for example, in the range of about 1 mm to about 3 cm. The lower limit of this range may also be about 2 mm or about 3 mm or about 5 mm, and the upper limit may also be about 2 cm or about 1.5 cm or about 1 cm or about 8 mm. According to one example, the thickness of the molded body 160 is not more than one fifth of a minimum edge length of the lateral sides 164 of the molded body 160.FIG. 3 shows a top view of a lead frame 300 arranged in a cavity of a mold 310. The lead frame 300 may be similar or identical to the lead frame 110 or to the lead frame 210, and the mold 310 may be similar or identical to the mold 160 or to the mold 220, respectively. In particular, the leadframe 300 may include the channels 212, 214 and / or the mold 310 may include the air outlets 140, 142. The lead frame 300 and the mold 310 may be used, for example, to manufacture the semiconductor package 100 or 200.As shown in FIG. 3, the mold 310 includes an inlet 320 and an outlet 330. The inlet 320 may be used to fill liquid molding material into the cavity of the mold 310, and the outlet 330 may be configured to allow excess liquid molding material to exit the cavity. For example, as shown in FIG. 3, the inlet 320 and the outlet 330 may be disposed at opposite lateral sides of the cavity of the mold 310. The outlet 330 may be arranged, for example, on the same lateral side as the air outlets 140, 142 or channels 212, 214. Further, the outlet 330 may be disposed laterally adjacent to the power lines 114, 116 (conversely, the inlet 320 may be disposed laterally adjacent to the control lines 118). In other words, neither the inlet 320 nor the outlet 330 is arranged above one of the lines 114, 114, 118.A cross section of the inlet 320 and a cross section of the outlet 330 can be larger, in particular significantly larger, than a cross section of the air outlets 140, 142 or channels 212, 214. At least for this reason, it may not be possible or practical to place the inlet 320 and the outlet 330 over one of the conduits 114, 116, 118 (there may not be sufficient space over the conduits 114, 116, 118).FIG. 4 is a flow diagram of an example method 400 for manufacturing a semiconductor package. The method 400 may be used, for example, to produce the semiconductor package 100 or 200.The method 400 includes a process of providing a leadframe including a die pad and a first power line at 401, the first power line including a first side and an opposing second side, a process of disposing at least one power semiconductor die on the die pad and electrically connecting the power semiconductor die to the first power line at 402, a process of disposing the leadframe in a cavity of a mold such that the first power line extends out of the cavity at a first lateral wall of the cavity, a process of providing an air outlet in the first lateral wall of the cavity, directly above the first side of the first power line such that the first side of the first power line forms a sidewall of the air outlet at 404, and / or providing a channel in the first side of the first power line, the channel configured to act as an air outlet for the cavity, and at 405 a process of filling the cavity with liquid molding material to form a mold body encapsulating the power semiconductor die, the air outlet allowing gas displaced from the cavity by the liquid molding material to exit the cavity.EXAMPLESHereinafter, the method for manufacturing a semiconductor package will be further explained using specific examples.Example 1 is a method of manufacturing a semiconductor package, the method comprising: providing a leadframe comprising a die pad and a first power line, the first power line comprising a first side and an opposing second side; disposing at least one power semiconductor die on the die pad and electrically connecting the power semiconductor die to the first power line; disposing the leadframe in a cavity of a mold tool such that the first power line extends out of the cavity at a first lateral wall of the cavity; providing an air outlet in the first lateral wall of the cavity, directly above the first side of the first power line, such that the first side of the first power line forms a side wall of the air outlet, and / or providing a channel in the first side of the first power line, the channel being configured to act as an air outlet for the cavity; and filling the cavity with liquid molding material to form a mold body encapsulating the power semiconductor die, the air outlet allowing gas displaced from the cavity by the liquid molding material to exit the cavity.Example 2 is the method of example 1, wherein the cavity comprises an inlet for the liquid molding material in a second sidewall of the cavity, the second sidewall opposing the first sidewall.Example 3 is the method of example 1 or 2, wherein the leadframe comprises a second power line arranged side by side with the first power line, and wherein the method further comprises providing a further air outlet in the first lateral wall of the cavity, directly above a first side of the second power line, such that the first side of the second power line forms a side wall of the further air outlet, and / or comprising providing a further channel in the first side of the second power line, wherein the further channel is configured to act as a further air outlet for the cavity.Example 4 is the method of any preceding example, wherein the method comprises providing a plurality of air outlets in the first sidewall of the cavity, directly above the first side of the first power line, such that the first side of the first power line forms a sidewall of the plurality of air outlets, and / or wherein the method comprises providing a plurality of channels in the first side of the first power line, wherein the plurality of channels is configured to act as air outlets for the cavity.Example 5 is the method of any of the preceding examples, wherein the air outlet has a height in the range from 10 μm to 50 μm, in particular in the range from 20 μm to 35 μm, wherein the height is measured perpendicular to the first side of the first power line.Example 6 is the method of any of the preceding examples, wherein the air outlet has a width in the range of 0.5 mm to 5 mm, in particular in the range of 1 mm to 1.5 mm, wherein the width is measured parallel to the first side of the first power line.Example 7 is the method of any of the preceding examples, wherein the first power line comprises lateral sides connecting the first and second sides, and wherein a width of the first power line is in the range of 5 mm to 20 mm, the width being measured between opposing lateral sides.Example 8 is the method of example 7, wherein the air outlet or the channel is centrally located between the opposing lateral sides.Example 9 is the method of any of the preceding claims, further comprising: removing a mold burr from the mold body at the location of the air outlet or the duct.Example 10 is the method of example 9, wherein removing the mold burr comprises using a chemical deburring process.Example 11 is the method of any of the preceding examples, further comprising: providing an outlet for the liquid molding material in the first sidewall of the cavity, laterally adjacent to the first power line.Example 12 is the method of any preceding example, wherein the at least one power semiconductor die is electrically connected to the first power line using one or more bond wires or straps, and wherein, upon filling the cavity, the liquid molding material flows past the one or more bond wires or straps and past the at least one power semiconductor die before reaching the air outlet or channel.Example 13 is the method of any of the preceding examples, wherein the molded body comprises four lateral sides, wherein the first power line is arranged at a first of the lateral sides, and wherein the lateral sides have edge lengths of 5.5 cm or more.Example 14 is the method of any of Examples 1 to 12, wherein the molded body comprises four lateral sides, wherein the first power line is arranged on a first of the lateral sides, and wherein the lateral sides have edge lengths in the range of 1.4 cm to 2.1 cm.Example 15 is the method of any of Examples 13 or 14, wherein a thickness of the molded body is not more than one fifth of a minimum edge length of the lateral sides of the molded body.Example 16 is an apparatus comprising means for performing the method according to any of the preceding examples.It should be noted that the methods and apparatuses, including preferred embodiments thereof, as set forth herein may be used alone or in combination with the other methods and apparatuses disclosed herein. In addition, the features set out in connection with a device can also be applied to a corresponding method and vice versa. Moreover, all aspects of the methods and apparatus set forth in the present document may be combined as desired. In particular, the features of the claims can be combined with one another in any desired manner.It should be noted that the description and drawings merely illustrate the principles of the proposed methods and systems. Those skilled in the art will be able to implement various arrangements which, although not expressly described or shown herein, embody the principles of the invention and are included within its spirit and scope. Moreover, all examples and embodiments set forth herein are intended to be expressly for illustrative purposes only in the nature of aid the reader in understanding the principles of the proposed methods and systems. Moreover, all statements herein providing principles, aspects, and embodiments of the invention, as well as specific examples thereof, are intended to encompass equivalents thereof.

Claims

A method of manufacturing a semiconductor package (100, 200), the method comprising: providing a leadframe (110, 210) comprising a die pad (112) and a first power line (114), the first power line (114) comprising a first side (114_1) and an opposing second side (114_2), disposing at least one power semiconductor die (120) on the die pad (112), and electrically connecting the power semiconductor die (120) to the first power line (114), disposing the leadframe (110, 210) in a cavity (132) of a mold (130) such that the first power line (114) extends out of the cavity (132) at a first sidewall (134) of the cavity (132), providing a plurality of air outlets (140) in the first side wall (134) of the cavity (132) directly above the first side (114_1) of the first power line (114), such that the first side (114_1) of the first power line (114) forms a side wall of the plurality of air outlets (140), and / or wherein the method comprises providing a plurality of channels (212) in the first side (114_1) of the first power line (114), wherein the plurality of channels (212) is configured to act as air outlets for the cavity (132) and filling the cavity (132) with liquid molding material (150) to form a molded body (160) encapsulating the power semiconductor die (120), wherein the plurality of air outlets enable, gas displaced from the cavity by the liquid molding material (150) leaves the cavity (132).The method of claim 1, wherein the cavity (132) comprises an inlet (320) for the liquid molding material (150) in a second sidewall of the cavity (132), the second sidewall opposing the first sidewall (134).The method of claim 1 or 2, wherein the leadframe (110, 210) comprises a second power line (116) arranged side by side with the first power line (114), and wherein the method further comprises providing a further air outlet (142) in the first side wall (134) of the cavity (132) directly above a first side of the second power line (116), such that the first side of the second power line (116) forms a side wall of the further air outlet (142), and / or providing a further channel (214) in the first side of the second power line (116), wherein the further channel (214) is configured to act as a further air outlet for the cavity (132).Method according to one of the preceding claims, wherein an air outlet of the plurality of air outlets has a height in the range from 10 μm to 50 μm, in particular in the range from 20 μm to 35 μm, wherein the height is measured perpendicular to the first side (114_1) of the first power line (114).Method according to one of the preceding claims, wherein an air outlet of the plurality of air outlets has a width in the range from 0.5 mm to 5 mm, in particular in the range from 1 mm to 1.5 mm, wherein the width is measured parallel to the first side (114_1) of the first power line (114).The method of any preceding claim, wherein the first power line (114) comprises lateral sides (114_3) connecting the first and second sides (114_1, 114_2), and wherein a width of the first power line (114) is in the range of 5 mm to 20 mm, the width being measured between opposing lateral sides (114_3).The method of any preceding claim, further comprising: removing a mold burr (162) from the mold body (160) at the location of the plurality of air outlets (140) or the plurality of channels (212).The method of claim 7, wherein removing the mold burr (162) comprises using a chemical deburring process.The method of any preceding claim, further comprising: providing an outlet (330) for the liquid molding material in the first sidewall (134) of the cavity (132) laterally adjacent the first power line (114).The method of any preceding claim, wherein the at least one power semiconductor die (120) is electrically connected to the first power line (114) using one or more bond wires or straps, and wherein, upon filling the cavity (132), the liquid molding material (150) flows past the one or more bond wires or straps and past the at least one power semiconductor die (120) before reaching the plurality of air outlets (140) or the plurality of channels (212).The method of any preceding claim, wherein the molded body (160) comprises four lateral sides (164), wherein the first power line (114) is arranged at a first of the lateral sides (164), and wherein the lateral sides (164) have edge lengths of 5.5 cm or more.The method of any of claims 1 to 10, wherein the molded body (160) comprises four lateral sides (164), wherein the first power line (114) is arranged at a first of the lateral sides (164), and wherein the lateral sides (164) have edge lengths in the range of 1.4 cm to 2.1 cm.The method according to any one of claims 11 or 12, wherein a thickness of the molded body (160) is not more than one fifth of a minimum edge length of the lateral sides (164) of the molded body (160).

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