Packaged Electronic Device

Abstract

Example embodiments relate to packaged electronic devices. One example packaged electronic device includes a substrate. The packaged electronic device also includes a plurality of leads fixated relative to the substrate in a spaced apart manner. Additionally, the packaged electronic device includes a solidified molding compound that is fixedly connected to the plurality of leads. The solidified molding includes an upper ring part that extends away from the leads in a direction away from the substrate. Further, the packaged electronic device includes an electronic component mounted on the substrate and electrically connected to the leads. In addition, the packaged electronic device includes a lid having a lid base and a lid rim that extends towards the upper ring part. The lid rim is connected to the upper ring part using an adhesive. Each of the lid rim and upper ring part include an inner portion and an outer portion.

Claims

1-27. (canceled)

28. A packaged electronic device, comprising: a substrate, wherein the substrate comprises a flange, a heatsink, or a die pad for mounting one or more semiconductor dies; a plurality of leads fixated relative to the substrate in a spaced apart manner; a solidified molding compound that is fixedly connected to the plurality of leads and that comprises an upper ring part that extends away from the leads in a direction away from the substrate; an electronic component mounted on the substrate and being electrically connected to the leads; a lid having a lid base and a lid rim that extends towards the upper ring part, wherein the lid rim is connected to the upper ring part by means of an adhesive, each of the lid rim and upper ring part comprising an inner portion and an outer portion relative to a center of the packaged electronic device, wherein the outer portions of the lid rim and upper ring part are connected to each other using said adhesive, wherein the outer portions of the lid rim and upper ring part co-define a channel in which the adhesive is arranged, wherein the inner portions of the lid rim and upper ring part abut each other without the adhesive being arranged in between them, wherein the channel widens in an outward direction relative to said center of the packaged electronic device, wherein the outer portion of the lid rim comprises a depression, wherein the upper ring part comprises a protrusion that extends in said depression, wherein the channel starts directly adjacent the inner portion of the upper ring part and in front of the protrusion when seen from the center of the packaged electronic device, wherein the inner portion of the lid rim comprises a first flank, wherein the inner portion of the upper ring part comprises a second flank, which flanks abut each other and each extend substantially parallel to the substrate, wherein the depression and the protrusion are formed adjacent to the flanks, wherein the protrusion comprises a third flank connected to the second flank and extending therefrom towards the lid rim, the protrusion further comprising a fourth flank connected to the third flank and ending at an outside surface of the packaged electronic device, wherein a part of the channel formed between the fourth flank and an opposing flank of the depression is wider than a part of the channel formed between the third flank and an opposing flank of the depression, and wherein the channel is open at an outside surface of the package device, and closed off at an opposing end of the channel due to the abutment of the first and second flanks.

29. The packaged electronic device according to claim 28, further comprising a cavity in between the substrate and the lid that is free from said molding compound, wherein the electronic component is arranged in the cavity, wherein the abutment of the inner portions of the lid rim and upper ring forms a mechanical barrier that prevented glue from reaching the cavity during connecting the upper ring part and lid rim to each other using the adhesive by application of heat and/or pressure and/or UV exposure.

30. The packaged electronic device according to claim 29, wherein each lead comprises a mounting region near an inward end of the lead that is free of molding compound, the packaged electronic device further comprising electrical connections, such as one or more bondwires, that electrically connect electrical terminals of the electronic component to the mounting regions of the leads.

31. The packaged electronic device according to claim 28, wherein the protrusion and depression are shaped to allow alignment of the lid relative to the upper ring part during application of the lid.

32. The packaged electronic device according to claim 28, wherein the depression and protrusion each extend along the entire circumference of the lid rim or upper ring.

33. The packaged electronic device according to claim 28, wherein the adhesive comprises a cured b-stage adhesive.

34. The packaged electronic device according to claim 28, wherein, viewed in a direction perpendicular to the substrate, a height of the protrusion is larger than a maximum inner size of the channel.

35. The packaged electronic device according to claim 28, wherein the molding compound comprises a lower ring part that fixates the plurality of leads relative to the substrate.

36. The packaged electronic device according to claim 28, wherein the electronic component comprises an integrated circuit (IC) chip and/or a semiconductor chip comprising one or more transistors.

37. The packaged electronic device according to claim 28, wherein the lid is made from the same molding compound as said solidified molding compound.

38. A method for manufacturing the packaged electronic device according to claim 28, comprising: a) providing a lead frame comprising a lead frame body and a substrate and a plurality of leads, wherein the substrate comprises a flange, a heatsink, or a die pad for mounting one or more semiconductor dies; b) applying a molding compound, for example by means of transfer or injection molding to the leads and substrate; c) allowing the applied molding compound to solidify thereby fixating the leads relative to the substrate in a spaced apart manner, wherein the solidified molding compound comprises an upper ring part that extends away from the leads in a direction away from the substrate, wherein the outer portion of the lid rim comprises a depression, and wherein the upper ring part comprises a protrusion that extends in said depression; d) mounting an electronic component on the substrate and electrically connecting the electronic component to the leads; e) providing a lid having a lid base and a lid rim that extends away from the lid base, wherein each of the lid rim and upper ring comprises an inner portion and an outer portion relative to a center of the packaged electronic device to be manufactured, wherein the inner portion of the lid rim comprises a first flank, wherein the inner portion of the upper ring part comprises a second flank, each of the first and second flank extending substantially parallel to the substrate, wherein the depression and the protrusion are formed adjacent to the first and second flanks, and wherein the protrusion comprises a third flank connected to the second flank and extending in said direction away from the substrate, the protrusion further comprising a fourth flank connected to the third flank and ending at an outside surface of the electronic device to be manufactured; f) positioning the lid and upper ring such that the inner portions of the lid rim and upper ring abut each other, said positioning resulting in the formation of a cavity in between the substrate and the lid in which the electric component is arranged, wherein the abutment of the inner portions of the lid rim and upper ring forms a mechanical barrier, wherein the outer portions of the lid rim and upper ring part are shaped such that they, after being positioned, co-define a channel that widens in an outward direction relative to said center of the packaged electronic device, wherein the channel starts directly adjacent the inner portion of the upper ring part and in front of the protrusion when seen from the center of the packaged electronic device, and wherein the channel is open at an outside surface of the package device, and closed off at an opposing end of the channel due to the abutment of the first and second flanks; and g) connecting the outer portion of the upper ring part and the outer portion of the lid rim to each other using the applied adhesive by the application of heat and/or pressure and/or UV exposure, wherein the mechanical barrier prevents glue from reaching the cavity during said connecting the upper ring part and lid rim to each other, wherein the inner portions of the lid rim and upper ring part abut each other without the adhesive being arranged in between them, wherein a part of the channel formed between the fourth flank and an opposing flank of the depression is wider than a part of the channel formed between the third flank and an opposing flank of the depression, wherein the adhesive comprises a b-stage adhesive, and wherein step e) comprises: e1) applying the adhesive solely to the outer portion of the lid rim; e2) heating the adhesive to remove a majority of solvent from the adhesive; and e3) storing the lid prior to further use.

39. The method according to claim 38, wherein the lead frame comprises a plurality of said substrates, and, for each of the substrates, a plurality of said leads, wherein the substrates and leads are connected to the lead frame body using one or more temporary connections such as connecting tabs and/or tie-bars, and wherein the steps b)-g) are performed on all the substrates and leads of the lead frame substantially simultaneously.

40. The method according to claim 39, wherein the leads are mutually connected using dam-bars.

41. The method according to claim 39, further comprising obtaining a plurality of said packaged electronic devices by means of sawing, punching, or cutting through the temporary connections and/or dam-bars after having performed step g).

Description

[0047] Next, the invention will be described in more detail referring to the appended drawings, wherein:

[0048] FIG. 1 illustrates a cross section of a known packaged electronic device;

[0049] FIG. 2A illustrates a cross section of a first embodiment of a packaged electronic device in accordance with the invention, and FIG. 2B a corresponding detailed view of the connection between the lid rim and upper ring part;

[0050] FIG. 3A illustrates a cross section of a second embodiment of a packaged electronic device in accordance with the invention, and FIG. 3B a corresponding detailed view of the connection between the lid rim and upper ring part; and

[0051] FIG. 4 illustrates a lead frame for manufacturing a plurality of packaged electronic devices as defined in claim 2A or 3A.

[0052] Comparing FIGS. 2A and 2B to the known package in FIG. 1, it can be seen that lid rim 8 comprises an inner portion 8A and an outer portion 8B. The same holds for upper ring part 6, which comprises an inner portion 6A and an outer portion 6B. Lower ring part 5 fixates leads 3 to substrate 2.

[0053] FIG. 2B illustrates how inner portion 6A of upper ring part 6 abuts with inner portion 8A of lid rim 8. It can be further seen that glue 122 is only present in channel 10 that is co-defined by outer portions 6B, 8B. FIG. 2B indicates that channel 10 is formed directly after inner portions 6A, 8A and before protrusion 12 that is formed in outer portion 6B, at least as seen from a center of packaged device 1. Moreover, channel 10 widens in the outward direction.

[0054] Protrusion 12 and recess 11, in which protrusion 12 extends, add to the lateral alignment of lid 7 relative to the remainder of the packaged device. On the other hand, the abutment of inner portions 6A, 8A allow for a well-defined height of the packaged device.

[0055] To manufacture device 1 in FIGS. 2A and 2B, adhesive 122 is arranged only in depression 11. Because electronic component 120 is already mounted at the time of applying the adhesive, it is preferred to couple lid 6 as soon as possible. For this reason, it is convenient to use an a-stage adhesive which requires a single heating step to couple lid rim 8 to upper ring part 6.

[0056] A different situation is shown in FIGS. 3A and 3B. Here, depression 11 is arranged in outer portion 8B, whereas protrusion 12 is formed in outer portion 6B. Here, it is possible to arrange the adhesive only in depression 11 at an earlier stage of manufacturing packaged device 1. For example, glue 122 may comprise a b-stage adhesive that has been partially cured to remove most of the solvent. In this stage, lid 8 may be stored for future use without risking the degradation of adhesive 122. At a later stage, lid 8 may be coupled to upper ring part 6 using a further heating step in which adhesive 122 cures.

[0057] Similar to FIG. 2B, channel 10 widens in an outward direction and starts directly after inner portions 6A, 8A and in front of protrusion 12, as seen from the center of packaged device 1.

[0058] Furthermore, in FIGS. 2B and 3B, it can be seen that inner portion 8A of lid rim 8 and inner portion 6A of upper ring part 6 comprise flanks 8A′, 6A′, respectively, that each extend substantially parallel to substrate 2. Therefore, when device 1 is arranged flat on a horizontal surface, flanks 8A′, 6A′ will constitute substantially horizontal surfaces. In this manner, the height of packaged device 1 in a direction perpendicular to substrate 2 is well defined as no adhesive is arranged in between flanks 6A′, 8A′.

[0059] Depression 11 and protrusion 12 are formed adjacent to flanks 8A′, 6A′. More in particular, protrusion 12 comprises a first flank 12A connected at a first connection point or line C1 to flank 8A′, as in FIG. 2B, or to flank 6A′, as in FIG. 3B, and extending from first connection point or line C1 towards upper ring part 6 or lid rim 8, respectively. Protrusion 12 further comprises a second flank 12B connected at a second connection point or line C2 to first flank 12A and ending at point or line E1 at an outside surface of packaged electronic device 1.

[0060] As can be seen in FIGS. 2B and 3B, a part of the channel formed between second flank 12B and opposing flank 11B of depression 11 is wider than a part of the channel formed between first flank 12A and opposing flank 11A of depression 11. Flank 11A is connected at a third connection point or line D1 to flank 6A′, as in FIG. 2B, or to flank 8A′, as in FIG. 3B. At a fourth connection point or line D2, flank 11B is connected to flank 11A, and flank 11B ends, at a point or line E2, at an outside surface of packaged electronic device 1.

[0061] Here, it is noted that the wording wider channel relates to the flow resistance encountered by the adhesive flowing in these channels when attaching the lid. More in particular, in a wider channel, the liquid adhesive may flow more easily than in a narrow channel. The width of the channel may be computed as the average cross sectional area computed perpendicular to a line or plane passing through the middle of the channel.

[0062] FIGS. 2B and 3B are cross sectional views Similar cross sectional views could be generated along the circumference of packaged device 1. For that reason, a point at which flanks connect, such as connection point C1 in FIG. 2B, actually corresponds to a line that extends around cavity 9 of packaged device 1.

[0063] Second flank 12B does not touch opposing flank 11B of depression 11. In this manner, the channel between depression 11 and protrusion 12 is open at an outer end, whereas an inner end is closed off due to the abutment of flanks 8A′, 6A′. Due to the open ended nature of the channel, there is little to no risk of air pockets forming in the adhesive. Such air pockets would degrade the reliability of the device when subjected to temperature and humidity stress tests. FIG. 4 illustrates a lead frame 20 for manufacturing a plurality of packaged electronic devices. Lead frame 20 comprises a plurality of substrates 2, a plurality of leads 3, and a lead frame body 23. Substrates 2 are connected to lead frame body 23 using tie-bars 24 which may include rivets 24A. In addition, leads 3 are connected to each other using dam-bars 25 and connected to lead frame body 23 using further connecting tabs 26. After having performed the steps described above related to connecting a lid to an upper ring part of a given package, the different electronic packages can be obtained by sawing, cutting, or punching through tie-bars 24, dam-bars 25, and connecting tabs 26.

[0064] Typically, substrates 2 are made from a different and/or thicker material than leads 3. Hence, substrates 2 may be connected, for example by means of rivets 24A, to lead frame body 23 at an earlier stage.

[0065] In the description above, the present invention has been described using detailed embodiments thereof. However, the skilled person will readily appreciate that the invention is not limited to these embodiments but that various modifications can be made without departing from the scope of invention which is defined by the appended claims.