Lead frame for semiconductor devices, corresponding semiconductor product and method

Abstract

Embodiments of this disclosure relate to lead frames for semiconductor devices, corresponding semiconductor products, and methods. One lead frame for a semiconductor device includes a die pad portion having a first planar die mounting surface and a second planar surface opposite the first surface. The first and second surfaces have facing peripheral edges that jointly define a peripheral contour of the die pad. The die pad includes at least one encapsulation molding compound receiving opening located at the periphery of the first planar surface.

Description

[0001] Priority requirements

[0002] This application claims priority to Italian Patent Application No. 102019000025009, filed on December 20, 2019, the entire contents of which are incorporated herein by reference to the fullest extent permitted by law. Technical Field

[0003] This manual relates to integrated circuit (IC) manufacturing technology.

[0004] In particular, one or more embodiments can be applied to semiconductor packages having exposed leads on the bottom of their package body, such as quad flat no leaded packages (QFN) or quad flat packages (QFP) with exposed pads (QFN-ep, QFP-ep), and methods of manufacturing thereof.

[0005] One or more embodiments can be applied to pre-molded leadframes that are molded in a flat configuration and are suitable for packaging applications using surface mount technology (SMT). Background Technology

[0006] Conventionally, IC dies are encased in plastic packages that provide protection against environmental factors and facilitate electrical interconnection between the IC die and the underlying substrate, such as a printed circuit board (PCB).

[0007] In a conventional arrangement, a packaged semiconductor device may include: a metal lead frame; at least one integrated circuit die; material for attaching the integrated circuit die to die pads in the lead frame; bonding wires for electrically connecting the pads on the IC die to the individual leads of the lead frame; and a rigid plastic encapsulation material, such as a molding compound plastic resin that covers other components and forms the exterior of the package.

[0008] A leadframe is a central support structure for IC dies, particularly used during the assembly of such packaged semiconductor devices to form external contacts (leads or pads). A portion of the leadframe may be completely encapsulated in plastic. The leads of the leadframe may extend from outside the package or be partially exposed within the encapsulation material to electrically connect the package to another component. In some packaged semiconductor devices, a portion of the die pads may also remain exposed outside the package, serving as a heat sink.

[0009] In the electronics field, a commonly known type of semiconductor packaging is called a Quad Flat Package (QFP). A QFP package can comprise a thin, typically square, package body defining four peripheral sides of substantially equal length. Protruding from each of the four peripheral sides of the package body are multiple leads, each typically in a gull-wing configuration. Multiple portions of the leads are internal to the package body and are electrically connected to corresponding pads or terminals in the semiconductor die, which is also encapsulated within the package body. The semiconductor die is mounted on the die pads of the QFP package lead frame. In some QFP package types, known as QFP Exposed Pad (QFP-ep) packages, one surface of the die pads is exposed within the bottom surface of the package body.

[0010] During reliability assessment, stress can be applied to the package, and adhesion between all components can be determined to assess package reliability. The adhesion of the lead frame to the resin is an important indicator of package tightness and reliability.

[0011] In QFN and QFP packaging technologies, external contacts (leads or pads) can be formed by photolithography, and as mentioned above, the bare pad portion of the lead frame supporting the IC die silicon chip can be exposed to the outside of the formed body.

[0012] In this regard, adhesion / strength is an issue, especially for pre-molded lead frames and / or when using tape bonding (e.g., for high-power applications).

[0013] Shrinkage of the molding compound on the die pads can cause compressive stress, potentially resulting in so-called "significant" warpage. This can cause the resin to separate from the leadframe due to lack of adhesion, i.e., delamination between the molding compound and the die pads. Die pad / molding delamination can compromise package heritability because the die pads can be pulled out of the molded body when mounted on a PCB.

[0014] To improve the reliability of resin-die pad coupling, existing solutions available from leadframe suppliers may include surface treatment of the die pads or customization of the leadframe under (photo) etching.

[0015] However, reliability tests performed on this arrangement indicate that delamination may still occur between the molding compound and the under-etched die pads, and the resulting gaps can affect the package's heritability.

[0016] There is a need in this field to provide improved solutions to address the above problems. Summary of the Invention

[0017] One or more embodiments relate to a system / device / circuit / method.

[0018] One or more embodiments facilitate improved anchoring of the die pad to the molding compound by providing a trench (formed by overlapping upper and lower half-cut patterns) around the die pad.

[0019] One or more embodiments may involve a corresponding lead frame.

[0020] An example of such a leadframe may include a bare die pad having a groove configuration on one side and a leadframe with a stepped profile.

[0021] One or more embodiments may involve corresponding semiconductor components.

[0022] One or more embodiments may involve corresponding methods.

[0023] A method for manufacturing leadframes or semiconductor components, with an improved delamination resistance manufacturing method being an example of such a method.

[0024] In one or more embodiments, it may facilitate the provision of QFP-ep packages with improved encapsulation and reduced (effectively removed) layering.

[0025] In one or more embodiments, the die pad region of the leadframe may include features to increase adhesion between the die pad region of the leadframe and subsequently applied molding compound. Such features may include a half-etch on the upper side of the die pad, the half-etch partially overlapping a second half-etch at the bottom of the die pad.

[0026] One or more embodiments may involve a corresponding lead frame.

[0027] One or more embodiments may create a locking resin that can help prevent delamination on die pads and increase the sealing of die pads in semiconductor components.

[0028] In one or more embodiments, such a trench partially pierces a semi-etched area on the periphery of the die pad, and the trench can facilitate the creation of a strong lock by molding compound to prevent the die pad from being pulled out of the molded body when mounted on a printed circuit board (PCB).

[0029] One or more embodiments may be applicable for use in QFN and QFP-ep semiconductor packages with photolithographic lead frames.

[0030] In one or more embodiments, the die pad may be designed to include one or more grooves on a surface.

[0031] One or more embodiments (among others) may advantageously facilitate: reducing or avoiding delamination between the molding compound resin and the die pads; improving the locking of the die pads in both directions during the assembly of the (pre)molded QFN leadframe; providing alternative surface treatments; and providing under-etched features on the photolithographic leadframe. Attached Figure Description

[0032] One or more embodiments will now be described by way of non-limiting example only, with reference to the accompanying drawings, in which:

[0033] Figure 1 This is a partial perspective view of the lead frame as seen from its back or bottom side;

[0034] Figure 2A and Figure 2B Is Figure 1 Examples of possible uses of the lead frame are illustrated below;

[0035] Figure 3 This is a partial perspective view of the lead frame of one or more embodiments, as seen from its front or top side;

[0036] Figure 4 This is a partial cross-sectional view of a lead frame according to one or more embodiments;

[0037] Figure 5 It is a scaled-up copy, indicated by the arrow V. Figure 4 A partial view, and illustrates the possible effects of the embodiment;

[0038] Figure 6 Here are flowchart examples of possible actions in the embodiments; and

[0039] Figure 7 This is an example diagram illustrating the basic principles of the embodiment. Detailed Implementation

[0040] In the following description, one or more specific details are shown to provide a thorough understanding of examples of embodiments of this specification. Embodiments may be obtained without one or more specific details, or using other methods, components, materials, etc. In other instances, known structures, materials, or operations are not described in detail so as not to obscure certain aspects of the embodiments.

[0041] References to "an embodiment" or "one example" within the framework of this specification are intended to indicate that a particular configuration, structure, or feature described in relation to an embodiment is included in at least one embodiment. Therefore, phrases such as "in one embodiment" or "in one example" that may appear at one or more points in this specification do not necessarily refer to one or the same embodiment.

[0042] Furthermore, specific constructions, structures, or features may be combined in any suitable manner in one or more embodiments.

[0043] The references used herein are provided for convenience only and therefore do not limit the scope of protection or the scope of the embodiments.

[0044] The accompanying drawings are simplified and not to a precise scale. For simplicity, terms of direction (up / down, etc.) or motion (forward / backward, etc.) may be used relative to the drawings. The term "coupling" and similar terms do not necessarily refer to direct and indirect connections, but also include connections via intermediate elements or devices.

[0045] As described above, improving the locking between the lead frame and the molding compound is an objective of one or more embodiments of this disclosure.

[0046] To improve lock-in, some solutions may include under-etching the leadframe during a half-etch operation to form a reversed T-shape, such as... Figure 1 , Figure 2A and Figure 2B As shown in the image.

[0047] Figure 1 This is a perspective view of a portion of a leadframe 10 (metal, such as copper) subjected to back-side etching as described below, the leadframe 10 comprising an array of leads 16 (electrical contact configurations) surrounding a die pad portion.

[0048] In one or more embodiments, the array of leads 16 may be selectively plated with the provided components using known methods.

[0049] As described above, the lead frame 10 may have a core or die pad 14 configured to carry a semiconductor die.

[0050] Specifically, the die pad 14 may include a first planar die mounting surface and a second planar surface 14b opposite to the first planar die mounting surface.

[0051] For example, a semiconductor die can be bonded to this first planar die mounting surface ( Figure 1 (Not visible in the middle) and the lead 16 can be configured to provide electrical connection and accessibility to the semiconductor die once placed on the die pad 14 of the lead frame 10.

[0052] In one or more embodiments, the die pad 14 may have a polygonal shape (e.g., a square) and may include a generally planar top surface and an opposing generally planar bottom surface, as well as four peripheral edge segments.

[0053] For example, as a result of etching, stepped contours 12 can be etched in the edge or contour of the die pad and in the edge or contour of the lead 16 of the lead frame.

[0054] Specifically, this photolithography process can be configured to provide a semi-etched leadframe 10, wherein the stepped profile 12 includes a first step and a second step, the first step having a width that is half the width of the leadframe before etching.

[0055] As described above, during the construction of the lead frame 10 via the etching process, the leads 16 may also be partially etched in a manner that facilitates the construction of continuous recessed shoulders within their surfaces, such shoulders extending continuously along the inner end and longitudinal side portions of each lead 16.

[0056] The components 100 of the lead frame 10 and the semiconductor die 30 can have, for example Figure 2A The cross-section shown illustrates that semiconductor dies (or multiple dies) can be placed on the first planar surface 14a of the die pads 14 of the lead frame 10.

[0057] Following the mechanical and electrical connection of the semiconductor die 30 to the lead 16, for example via the use of conductive wires (referred to as wire bonding, not shown in the figure), the assembly 100 can be encapsulated or covered by an encapsulating material in a molding process, allowing the encapsulating material to harden, thereby constructing the package body of the semiconductor package. The encapsulating material is applied to the lead frame 10 such that, in the fully formed package body, the second planar surface 14b (bottom surface) of the die pad 14 and the "bottom" surface 16b of the lead 16 (opposite to the corresponding "top" surface 16a) are exposed within the "bottom" surface of the packaged assembly 100, wherein the bottom surface of the packaged assembly 100 can be configured to couple to a support S. In one or more embodiments, for example, such a support S may include a printed circuit board (PCB).

[0058] For example, the lead frame 10 can be assembled as follows: Figure 2B The pre-molded lead frame 1000 shown has, for example, a space filled with molding compound 40' between the die pad 14 and the lead 16, wherein the second planar surface 14b of the die pad 14 and the top surface 16b of the lead 16 can remain visible to external inspection.

[0059] As described above, the packaged semiconductor device or pre-molded lead frame 1000 may have improved resistance to delamination forces that can lead to deterioration of adhesion between the molded part and the lead frame.

[0060] In particular, the improved resistance can be generated by the presence of stepped contours 12 or recessed shoulders in the edge of the die pad, which can resist delamination forces parallel to the first planar surface 14a (die pad plane).

[0061] However, this stepped profile offers little protection against reaction forces acting in other directions, such as those perpendicular to the die pad surface. In any case of deterioration in adhesion between the molded part and the leadframe, the lack of protection against such (non-parallel) forces can lead to, for example, the leadframe potentially “slipping” off its base due to the action of these forces.

[0062] One or more embodiments of this disclosure are intended to provide this improved adhesion between the leadframe die pad 14 and the molding compound 40 relative to a delamination force acting in any direction.

[0063] In such Figure 3 In one or more embodiments shown, this improvement can be facilitated via a die pad 14 of a lead frame 20 including at least one engraved feature 18 (e.g., having an ellipse or opening) extending through a first step in the stepped profile 12 outlining the die pad 14. The engraved feature 18 includes a portion 18a that extends fully through the die pad 14 and another portion 18b that extends only partially through the die pad 14 to define a bottom surface or step 13.

[0064] The lead frame 20 can be formed from rolled strip metal material by wet chemical etching or mechanical stamping using a progressive die. Photochemical etching (also known as chemical milling) is a process that uses photolithography and metal-dissolving chemicals to etch a pattern onto a metal strip. Photoresist is exposed to ultraviolet light through a photomask with the desired pattern, and then developed and cured. Chemicals are sprayed or otherwise applied to the masked strip, and the exposed portions of the strip are then etched, leaving the desired pattern.

[0065] As described above, the lead frame 20 can be formed by photolithography or chemical etching of rolled strip metal material from both sides using a conventional liquid etchant. The etching process can be stopped early to provide under-etching of various surfaces of the lead frame 20 to achieve the desired cross-sectional configuration, such as... Figure 2A and / or Figure 2B or Figure 7 As shown in the image.

[0066] In particular, in such Figure 7In one or more embodiments shown, different masked strips can be used on different sides of the leadframe. For example, a first mask 70 can be used to etch (e.g., using a first etch stream from top 700) a first planar surface 14a (top surface) to form a first etched portion extending to the front die mount leadframe surface and only partially through the leadframe, and a second mask 72 can be used to etch (e.g., using a second etch stream from bottom 720) a second planar surface 14b (bottom surface) to form a second etched portion extending to the rear leadframe surface and only partially through the leadframe. In one or more embodiments, applying such differentiated etching processes 700, 720 can facilitate obtaining different (engraved) patterns on different leadframe surfaces and thus define the engraved structure 18 (cavity).

[0067] Figure 4 This is an example of a portion of one or more embodiments of the lead frame 20 component 20 and the semiconductor die 30 encapsulated with the encapsulation molding compound 40. For example, the semiconductor die 30 may be coupled to a second surface or "top" surface of the die pad 14 and may be coupled to the lead 16 via (wire bonding) contact 32.

[0068] Figure 5 yes Figure 4 A magnified view of part V. In, as... Figure 5 In one or more embodiments shown, due to the presence of an engraved structure 18 extending through the stepped profile 12 of the die pad 14, the molding compound is coupled to the die pad 14 via an anchoring portion 15 during casting, as a result of filling the engraved structure 18 with the molding compound. Depending on the size of the step in the edge (e.g., a first step 13 in the stepped profile 12 of the die pad 14), the anchoring portion 15 relative to the first planar surface 14a (die pad surface) can be of various sizes and proportions.

[0069] In such Figure 3 In one or more embodiments shown, the engraved structure 18 may have the shape of an elliptical groove, which is merely exemplary and has no limitation. For example, the engraved structure 18 may have other polygonal shapes or include patterns such as parallel, elliptical, or polygonal structures.

[0070] In such Figure 6 In one or more embodiments shown, a method 400 for manufacturing a pre-molded lead frame and / or semiconductor device according to the present disclosure may include:

[0071] - Provides a 410 (metal, such as copper) leadframe, the leadframe 10 including die pads 14 and multiple leads 16;

[0072] - Apply under-etching 412 (e.g., photolithography or chemical etching) to the first side of the lead frame 10 to add a stepped profile to the outline of the die pad 14 and symmetrically mirror the lead profiles in the plurality of leads 16, the stepped profile including a first step and a second step.

[0073] - Apply an etching process 412 (e.g., photolithography or chemical etching) to the second side of the lead frame, particularly to the second surface of the die pad 14 in the lead frame, so as to etch at least one structure and / or a pattern of structure through the first step in the stepped profile 12 that outlines the die pad 14.

[0074] - Couple the semiconductor die 414 to the second planar surface (die pad surface) of the die pad 14;

[0075] - (e.g., via wire-bonded contact 32) electrically couple the semiconductor die 30 416 to the lead 16 in the lead frame; and

[0076] - Apply molding compound 418 to fill the volume including at least the lead frame 10, and fill the volume in such a way that a second planar surface 14b (second die pad surface) opposite the first planar surface 14a (first die mount surface) of the die pad is exposed to the outside, and wherein at least one engraved structure 18 etched in the die pad 14 is filled by the molding compound 40.

[0077] Therefore, method 400 may include providing at least one of 420 semiconductor device 200 and / or pre-molded lead frame 2000, which has improved robustness against delamination forces acting in any direction.

[0078] One or more embodiments relate to a leadframe (e.g., 10) for a semiconductor device, the leadframe including a die pad portion (e.g., 14) having a first planar surface (e.g., 14a) and first and second planar surfaces (e.g., 14b) opposite the first surface, the first and second planar surfaces (e.g., 14a and 14b) having facing peripheral edges that together define a peripheral contour of the die pad, wherein the die pad includes at least one encapsulation molding compound receiving opening, the at least one encapsulation molding compound receiving engraving (e.g., 18, opening) being located at the periphery of the first planar surface.

[0079] In one or more embodiments, the at least one encapsulating molding compound receiving cavity may include an engraved structure (e.g., 18, through-cavity) extending from the first planar surface to the second planar surface.

[0080] In one or more embodiments, the at least one encapsulating molding compound of the receiving cavity may have an opening at the first plane, the opening having a closed profile and being spaced at a distance from the peripheral edge of the first plane.

[0081] In one or more embodiments, the peripheral edges of the first surface and the second surface may be offset from each other to provide a stepped peripheral profile of the die pad, wherein the peripheral of the first planar surface has a protruding peripheral region relative to the second planar surface, and wherein at least one encapsulation molding compound of the receiving cavity is provided at the protruding region of the first planar surface.

[0082] In one or more embodiments, the at least one encapsulating molding compound receiving cavity may include a buttonhole-shaped cavity.

[0083] In one or more embodiments, the lead frame may include a plurality of the encapsulation molding compound receiving cavities distributed along the peripheral contour of the die pad.

[0084] In one or more embodiments, the lead frame may have an encapsulation molding compound (e.g., 40') molded thereon, the encapsulation molding compound being flush with the first planar die mounting surface and the second planar surface, the encapsulation molding compound (e.g., 40) filling the opening of the at least one encapsulation molding compound receiving cavity at the periphery of the first planar surface.

[0085] One or more embodiments may relate to a semiconductor product (e.g., 200) including: a lead frame (e.g., 10) according to one or more embodiments; and at least one semiconductor die (e.g., 30) of the first planar surface (e.g., 14a) coupled to a die pad (e.g., 14) in the lead frame.

[0086] In one or more embodiments, the semiconductor product may include: a conductively bonded contact (e.g., 32) electrically coupling the at least one semiconductor die to the lead frame; and / or an encapsulating molding compound (e.g., 40) encapsulating the at least one semiconductor die, the at least one semiconductor die being coupled to the first planar surface in the die pads of the lead frame.

[0087] One or more embodiments may relate to a method that may include: providing (e.g., 410) a leadframe (e.g., 10) for a semiconductor device, the leadframe including a die pad portion (e.g., 14) having a first planar surface (e.g., 14a) and a second planar surface (e.g., 14b) opposite the first surface; applying an etching process (e.g., 412), preferably a photolithography process, to the first surface and the second surface, the first surface and the second surface having facing peripheral edges that together define a peripheral contour of the die pad, wherein the die pad includes an opening of at least one encapsulation molding compound receiving cavity at the periphery of the first planar surface.

[0088] In one or more embodiments, the method may include coupling (e.g., 30) at least one semiconductor die to the first planar surface of a die pad in a leadframe.

[0089] In one or more embodiments, the method may include: electrically coupling the at least one semiconductor die to the lead frame; and / or encapsulating (e.g., 40) the at least one semiconductor die coupled to the first plane in the die pads of the lead frame.

[0090] It should also be understood that the various individual implementation options shown in the accompanying drawings of this specification are not necessarily employed in the same combinations shown in the drawings. Therefore, one or more embodiments may employ these (furthermore, non-mandatory) options individually and / or in different combinations relative to the combinations shown in the drawings.

[0091] Details and embodiments may vary, even significantly, relative to what has been described by way of example only, without departing from the scope of protection, without prejudice to the fundamental principles. The scope of protection is defined by the appended claims.

Claims

1. A leadframe for a semiconductor device, comprising: a die pad portion having a first planar die mounting surface and a second planar surface opposite the first planar die mounting surface, the first planar die mounting surface and the second planar surface having facing peripheral edges that collectively define a peripheral outline of the die pad; and at least one cavity extending through the die pad from the first planar die mounting surface to the second planar surface to define an anchor portion of the die pad between the at least one cavity and the peripheral outline; wherein the at least one cavity includes: a first etched portion extending into the first planar die mounting surface to a first depth, the first depth being less than a thickness of the die pad; and a second etched portion extending into the second planar surface to a second depth, the second depth being less than the thickness of the die pad; wherein a bottom of the first etched portion defines a step surface within the at least one cavity, the step surface extending parallel to the first planar die mounting surface, and the second etched portion defines a thickness of the anchor portion, the thickness of the anchor portion being less than the thickness of the die pad.

2. The leadframe of claim 1, wherein each cavity is configured to receive a package molding compound.

3. The leadframe of claim 1, wherein the first etched portion of the at least one cavity defines a mouth at the first planar die mounting surface, the mouth having a closed outline and being a distance from the peripheral edge of the first planar die mounting surface.

4. The leadframe of claim 1, wherein the peripheral edges of the first planar die mounting surface and the second planar surface are offset from one another to provide a stepped peripheral outline of the die pad, wherein a periphery of the first planar die mounting surface has a peripheral region that projects relative to the second planar surface, wherein the at least one cavity is disposed at the peripheral region of the first planar die mounting surface.

5. The leadframe of claim 1, wherein the at least one cavity comprises a grommet-like cavity.

6. The leadframe of claim 1, wherein the at least one cavity comprises a plurality of cavities distributed along a peripheral outline of the die pad.

7. The leadframe of claim 1, further comprising: a molded package molding compound on the leadframe, flush with the first planar die mounting surface and the second planar surface, the package molding compound filling the at least one cavity.

8. The leadframe of claim 1, wherein the first etched portion and the second etched portion collectively form a portion of the at least one cavity that extends completely through a thickness of the die pad.

9. A semiconductor product, comprising: the leadframe of claim 1; and at least one semiconductor die coupled to the first planar die mounting surface in the die pad of the leadframe.

10. The semiconductor product of claim 9, comprising: a conductive structure electrically coupling the at least one semiconductor die to the leadframe.

11. The semiconductor product of claim 9, comprising: a package molding compound encapsulating the at least one semiconductor die coupled to the first planar die mounting surface in the die pad of the leadframe.

12. A method of manufacturing a semiconductor device, comprising: providing a leadframe for the semiconductor device, the leadframe including a die pad portion having a first planar die mounting surface and a second planar surface opposite the first planar die mounting surface, the first planar die mounting surface and the second planar surface having facing peripheral edges that collectively define a peripheral outline of the die pad; applying an etching process to the first planar die mounting surface and the second planar surface; wherein the etching process defines a cavity opening at a periphery of the first planar die mounting surface, the cavity including: a first etched portion extending into the first planar die mounting surface to a first depth, the first depth being less than a thickness of the die pad; and a second etched portion extending into the second planar surface to a second depth, the second depth being less than the thickness of the die pad; wherein a bottom of the first etched portion defines a step surface within the cavity, the step surface extending parallel to the first planar die mounting surface, and the second etched portion defines an anchor portion thickness, the anchor portion thickness being less than the thickness of the die pad; wherein the anchor portion is located between the cavity and the peripheral outline.

13. The method of claim 12, further comprising: filling the cavity with a package molding compound.

14. The method of claim 12, comprising: coupling at least one semiconductor die to the first planar surface in the die pad of the leadframe.

15. The method of claim 14, comprising: electrically coupling the at least one semiconductor die to the leadframe.

16. The method of claim 14, comprising: encapsulating the at least one semiconductor die coupled to the first planar surface in the die pad of the leadframe.

17. A leadframe for a semiconductor device, comprising: a die pad portion having a first planar die mounting surface and a second planar surface opposite the first planar die mounting surface, the first planar die mounting surface and the second planar surface having facing peripheral edges that collectively define a peripheral outline of the die pad; and at least one cavity extending through the die pad from the first planar die mounting surface to the second planar surface to define an anchor portion of the die pad located between the at least one cavity and the peripheral outline; wherein the at least one cavity includes: a first opening extending into the first planar die mounting surface; and a second opening extending into the second planar surface. ​ wherein the first opening and the second opening have depths that cause the first opening and the second opening to be connected to one another; and wherein the first opening is offset from the second opening such that a connection between the first opening and the second opening is less than either of the first opening and the second opening.

18. The leadframe of claim 17, wherein a depth of the first opening defines a stepped surface within the at least one cavity, the stepped surface extending parallel to the first planar die mount surface, and wherein a depth of the second opening defines a thickness of the anchor portion, the thickness of the anchor portion being less than a thickness of the die pad.

19. The leadframe of claim 17, wherein the peripheral edges of the first planar die mount surface and the second planar surface are offset from one another to provide a stepped peripheral profile of the die pad, wherein a periphery of the first planar die mount surface has a peripheral region that protrudes relative to the second planar surface, wherein the at least one cavity is disposed at the peripheral region of the first planar die mount surface.

20. The leadframe of claim 17, further comprising: molded package molding compound on the leadframe that is flush with the first planar die mount surface and the second planar surface, the package molding compound filling the at least one cavity.

21. A method of manufacturing a semiconductor device, comprising: providing a leadframe for the semiconductor device, the leadframe including a die pad portion having a first planar die mount surface and a second planar surface opposite the first planar die mount surface, the first planar die mount surface and the second planar surface having facing peripheral edges that collectively define a peripheral profile of the die pad; and forming a cavity extending from the first planar die mount surface through the die pad to the second planar surface to define an anchor portion of the die pad; wherein forming the cavity includes: etching a first opening extending into the first planar die mount surface; etching a second opening extending into the second planar surface; wherein the first opening and the second opening have depths that cause the first opening and the second opening to be connected to one another; and wherein the first opening is offset from the second opening such that a connection between the first opening and the second opening is less than either of the first opening and the second opening.

22. The method of claim 21, further comprising: filling the cavity with a package molding compound.

Images