Semiconductor device

Abstract

A semiconductor device is provided. The semiconductor device includes: a lead frame; and one or more dies, the one or more dies being fixed to the lead frame. The semiconductor device further includes a clip fixed to at least one of the one or more dies; a first heat sink fixed to the jig or formed as a part of the jig; and a cap at least partially surrounding the lead frame, the one or more dies, and the clip. A major surface of the cover defines an aperture extending to the first heat sink. The semiconductor device further includes a first metal layer fixed to the first main surface of the cover body by means of a dual-function adhesive; and a second heat sink coupled to the first metal layer.

Description

Technical Field

[0001] The present invention relates to a semiconductor device and to a method. Background Art

[0002] Semiconductor devices such as MOSFETs are used in many applications. The semiconductor device may include one or more heat sinks provided for increasing heat dissipation of the device.

[0003] The present invention seeks to eliminate or at least mitigate problems associated with known devices, whether or not those problems are identified herein. Summary of the Invention

[0004] In a first aspect of the present invention, there is provided a semiconductor device. The semiconductor device includes: a lead frame; and one or more dies fixed to the lead frame. The semiconductor device further includes: a clamp fixed to at least one of the one or more dies; a first heat sink fixed to the clamp or formed as part of the clamp; and a cover at least partially surrounding the lead frame, the one or more dies and the clamp. The main surface of the cover defines an opening extending to the first heat sink. The semiconductor device further includes a first metal layer fixed to the first main surface of the cover by a bifunctional adhesive; and a second heat sink coupled to the first metal layer.

[0005] The device may be a MOSFET.

[0006] The first metal layer may be formed by electroless plating.

[0007] Traditionally, in a semiconductor device, a first (or internal) heat sink is provided and a second (or external) heat sink is fixed to the first (or internal) heat sink. The first heat sink is fixed to the clamp or formed as part of the clamp. The area of the first heat sink available for fixing the second heat sink is the area of the first heat sink that is exposed through an opening formed in the cover of such a device.

[0008] The first metal layer of the semiconductor device in this aspect of the present invention serves as a base for fixing the second heat sink. Since the first metal layer is fixed to the first main surface of the cover body, the available contact area between the second heat sink and the first metal layer is larger than that of conventional devices. Since the amount of heat dissipated from the second heat sink increases, and thus the amount of heat dissipated from the device increases, it is desirable to increase the contact area. Since the possibility of overheating is advantageously reduced, it is desirable to increase the amount of heat dissipated from the device. In addition, increasing the amount of heat dissipated from the device will lower the temperature of the device, especially during operation. This reduces the resistance between the drain and source of the device (i.e., the RDS(on) of the device decreases). Reducing the RDS(on) of the device is desirable because it results in improved efficiency of the device.

[0009] In use, the device is subject to stress. The stress may be generated due to, for example, temperature fluctuations and / or device deformation. Since the contact area between the second heat sink and the first heat sink can be larger than that of conventional devices, the stress distribution to which the device is subjected during use is more uniform. This reduces the possibility of stress concentration occurring during use. Stress concentrations are not desirable because they can cause, for example, delamination of the device, which ultimately leads to device failure. Therefore, by increasing the potential contact area between the second heat sink and the first heat sink, the device is more robust than conventional devices.

[0010] In a conventional device, the area of the internal heat sink that can be used to fix the external heat sink is defined by the cover body (i.e., by the opening that extends through the cover body to the internal heat sink). This is because the external heat sink is typically fixed to the main heat sink at the area where the internal heat sink is exposed through the opening formed in the cover body. Since the first metal layer is fixed to the first main surface of the cover body, the area that can be used to fix the second heat sink is not defined at its outer edge in the same way as in conventional devices. This allows the second heat sink to be more easily fixed to the first metal layer, which reduces the possibility of defective attachment of the second heat sink. This is in comparison to the attachment of the external heat sink in conventional devices.

[0011] The first metal layer and the second heat sink can define an orientation identification portion.

[0012] The phrase "orientation identification portion" can be understood to refer to one or more regions of the first metal layer that allow the orientation of the semiconductor device to be determined.

[0013] The orientation identification portion can be defined by the absence of material.

[0014] The orientation identification portion can be provided at the periphery of the first metal layer.

[0015] In use, the semiconductor is assembled onto a printed circuit board. In the case where the first metal layer and the second heat sink define an orientation identification portion, the correct orientation of the device for assembly onto the printed circuit board can be easily determined. Advantageously, this simplifies the assembly of the device onto the printed circuit board, thereby allowing the device to be efficiently assembled onto the printed circuit board.

[0016] The footprint of the first metal layer and the footprint of the second heat sink may be discontinuous.

[0017] Here and throughout this document, the term "footprint" of a component may be understood to refer to the planar area of the component as observed in a plan view.

[0018] Here and throughout this document, a discontinuous footprint may be understood to mean that one or more surface irregularities are formed within the periphery of the footprint, preferably in the form of openings.

[0019] In the case where the footprint of the first metal layer and the footprint of the second heat sink are discontinuous, the combined exposed surface area of the first metal layer and the second heat sink is increased. This is compared to the case where the footprint of the first metal layer and the footprint of the second heat sink are continuous.

[0020] The semiconductor device may further include an array of openings. Each opening in the array of openings may extend from the main surface of the second heat sink to the main surface of the cover body.

[0021] Each opening in the array of openings may be in the form of a blind hole.

[0022] In the case where an array of openings is provided, the heat dissipation of the device is increased. This further reduces RDS(on) and the likelihood of overheating of the device in use.

[0023] The second heat sink may define a main surface and a plurality of side walls extending from the first metal layer to the main surface. The angle between the first main surface of the cover body and each of the plurality of side walls may be at least 30 degrees.

[0024] Each of the plurality of side walls may extend substantially perpendicular to the first main surface of the cover body.

[0025] Here and throughout this document, the angle between the first main surface of the cover body and each of the side walls refers to the exterior angle defined between the first main surface of the cover body and each of the side walls.

[0026] The main surface of the second heat sink may be referred to as the upper surface of the second heat sink or as the second main surface.

[0027] In the case where the second heat sink is fixed to the first metal layer via a solder layer, the angle between the plurality of side walls and the first main surface of the cover body is at least 30 degrees, which advantageously allows for easy visual inspection of the quality of the joints formed by the solder layer. This allows for faster inspection of the joints, and reduces the likelihood of defective joints being overlooked, thereby improving manufacturing efficiency.

[0028] In the case where the second heat sink is formed by, for example, 3D printing or electroplating, the plurality of side walls extending perpendicular to the first main surface of the cover body advantageously allows for easy inspection of the interface between the second heat sink and the first metal surface. This allows for faster inspection of the interface, and reduces the likelihood of defective interfaces being overlooked, thereby improving manufacturing efficiency.

[0029] The second heat sink may extend continuously from the first metal layer.

[0030] The second heat sink may be coupled to the first metal layer by means of an adhesive.

[0031] The adhesive may be a solder layer.

[0032] The contact area between the first metal layer and the cover body may be at least 50% of the area of the main surface of the cover body.

[0033] Here, the "area of the main surface of the cover body" refers to the overall area of the first main surface of the cover body.

[0034] The contact area between the first metal layer and the cover body may be at least 75% of the area of the main surface of the cover body.

[0035] In the case where the contact area between the first metal layer and the cover body is at least 50% of the area of the main surface of the cover body, the heat dissipation of the device can be optimized.

[0036] The coverage area of the second heat sink may correspond to the coverage area of the first metal layer.

[0037] Here and throughout this document, the coverage area of the second heat sink corresponding to the coverage area of the first metal layer can be understood to mean that the coverage areas are substantially the same in shape and size.

[0038] In the case where the coverage area of the second heat sink corresponds to the coverage area of the first metal layer, the heat dissipation of the device is optimized.

[0039] In a second aspect of the present invention, there is provided a method, the method comprising: providing a semiconductor device. The semiconductor device includes: a lead frame; one or more dies, the one or more dies being fixed to the lead frame; a fixture fixed to at least one of the one or more dies; a first heat sink fixed to the fixture or formed as part of the fixture; a cover at least partially surrounding the lead frame, the one or more dies, and the fixture. An outer surface of the cover defines a main surface. The cover includes an opening extending to the first heat sink. The method further comprises: applying a dual-functional adhesive layer to a first main surface of the cover; applying a catalytic layer to the dual-functional adhesive layer; forming a first metal layer on the catalytic layer such that the first metal layer is fixed to the dual-functional adhesive layer; and coupling a second heat sink to the first metal layer.

[0040] It should be understood that the advantages associated with the first aspect of the present invention are also applicable to this second aspect, with necessary modifications.

[0041] The method may further comprise: before applying the dual-functional adhesive, using a masking device to mask one or more regions of the first main surface of the cover. The masking device may be configured to prevent the dual-functional adhesive from bonding to the one or more regions of the first main surface of the cover masked by the masking device.

[0042] The geometry of the masking device may be such that the first metal layer defines an orientation identification portion.

[0043] The geometry of the masking device may be such that the dual-functional adhesive is applied to the first main surface of the cover in a discontinuous manner.

[0044] The second heat sink may be coupled to the first metal layer by printing the second heat sink onto the first metal layer.

[0045] The second metal layer may be formed by electroplating.

[0046] The second heat sink may be coupled to the first metal layer by means of an adhesive.

[0047] The first metal layer may be formed using electroless plating.

[0048] Features disclosed with respect to one aspect of the present invention may be suitably combined with another aspect of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0049] Embodiments of the present invention will now be described with reference to the accompanying drawings, wherein:

[0050] Figure 1 A portion of a semiconductor device according to an embodiment of the present invention is shown.

[0051] Figure 2 Showing where the cover is in place Figure 1of the semiconductor device.

[0052] Figure 3 shows the semiconductor device in which the second heat sink is in place Figure 1 and 2 of the semiconductor device.

[0053] Figure 4 and 5 shows the semiconductor device of the foregoing figure during the manufacture of the device.

[0054] Figure 6 and 7 shows an alternative embodiment of the semiconductor device. Detailed Description

[0055] Figure 1 shows the semiconductor device 2. The semiconductor device 2 includes a lead frame 4. The semiconductor device 2 includes a die 6. The die 6 is fixed to the lead frame 4. The semiconductor device 2 includes a clamp 8. The semiconductor device includes wiring 7. The semiconductor device 2 further includes a cover (not shown for clarity Figure 1 in the figure).

[0056] The lead frame 4 serves as the base of the semiconductor device 2 to which the other components of the device are attached. In the depicted embodiment, the lead frame 4 includes a first part 4a, a second part 4b, and a third part 4c. However, in some un-depicted embodiments, the lead frame 4 may include any suitable number of parts. For example, the lead frame 4 may include only a single part. The lead frame 4 includes a plurality of connection points 5 (only one of which is labeled in Figure 1 the figure). The plurality of connection points 5 allows the semiconductor device 2 to be connected to an external circuit (not shown). The lead frame 4 is made of a conductive material such as copper (including copper alloys).

[0057] The die 6 is fixed to the lead frame 4. The die 6 is fixed to the lead frame 4 by means of an adhesive such as a solder layer. The die 6 may be a single component or may include a plurality of constituent components. The die 6 is made of semiconductor material. The die 6 is generally rectangular in shape, but may also be any other suitable shape. The die 6 is in the shape of a plate.

[0058] The clamp 8 electrically couples and mechanically couples the second part 4b of the lead frame 4 to the die 6. Thus, the clamp 8 also electrically couples and mechanically couples the first part 4a of the lead frame 4 to the second part 4b of the lead frame 4.

[0059] The device 2 includes a first heat sink 9. In the depicted embodiment, the heat sink 9 is integrally formed with the clamp 8. However, the heat sink 9 may be formed separately from the clamp 8 and fixed to the clamp 8 by means of an adhesive such as a solder layer. The first heat sink 9 is provided to increase the rate of heat dissipation from the device 2.

[0060] The wiring 7 electrically couples the first part 4a of the lead frame 4 to the third part 4c of the lead frame 4. The wiring 7 can be attached to the lead frame 4 by, for example, ultrasonic welding. However, other methods for securing the wiring 7 to the lead frame 4 can be used. In some embodiments, the clamp 8 can electrically couple the first part 4a of the lead frame 4 to the third part 4c of the lead frame 4.

[0061] Figure 2 The device 2 with the cover 10 in place is shown. As will be discussed below, a second heat sink ( Figure 2 not shown in the figure) is secured to the cover 10. The cover 10 at least partially surrounds the lead frame 4, the die, and the clamp 8 (the die is not visible in Figure 2 the figure - they are located within the cover 10). In the depicted embodiment, the cover 10 encapsulates the remaining components of the device 2 (i.e., the lead frame 4, the die 6, and the clamp 8). A plurality of connection points 5 of the lead frame 4 extend through the cover 10. This allows the connection points 5 to be connected to an external circuit (not shown). The cover 10 can also be referred to as an isolator, a housing, or an encapsulant. The cover 10 can be made of any suitable electrically insulating material such as epoxy resin.

[0062] The cover 10 defines a first major surface 12. The first major surface 12 can be described as the upper surface of the cover 10 and / or the device 2. The first major surface 12 is the outer surface of the cover 10. The cover 10 defines a plurality of side surfaces 14a, 14b (only two of which are visible in Figure 2 the figure). The side surfaces 14a, 14b are the outer surfaces of the cover 10. Each of the plurality of side surfaces 14a, 14b abuts the first major surface 12 of the cover 10. Each of the plurality of side surfaces 14a, 14b abuts the periphery of the first major surface 12 of the cover 10. A plurality of connection points 5 extend through the side surface 14b. The first major surface 12 defines an opening 18. The opening 18 extends to the first heat sink 9.

[0063] Figure 3 The device 2 with the second heat sink 20 in place is shown. The second heat sink is coupled to a first metal layer (not visible in Figure 3 the figure). The first metal layer is secured to the first major surface 12 of the cover 10 by means of a bifunctional adhesive. The first metal layer will be discussed in more detail below. The second heat sink 20 further increases the rate of heat dissipation from the device 2. The second heat sink 20 is formed of a metal material, preferably copper or a copper alloy. As will be further discussed below, the second heat sink 20 can be formed by 3D printing or electroplating. As an alternative, the second heat sink 20 can be secured to the first metal layer by means of a solder layer ( Figure 3 not shown in the figure).

[0064] The second heat sink 20 includes a plurality of side walls 21a, 21b (only two of which are visible in Figure 3 ). The second heat sink 20 includes a main surface 32. The main surface 32 of the second heat sink 20 may be referred to as the upper surface of the second heat sink 20. The plurality of side walls 21a, 21b extend around the periphery of the main surface 32. Each of the plurality of side walls 21a, 21b extends from the first metal layer to the main surface 32. The plurality of side walls 21a, 21b extend perpendicular to the first main surface 12 of the cover body 10. In the case where the second heat sink 20 is fixed to the first metal layer by a solder layer, the plurality of side walls 21a, 21b extending perpendicular to the first main surface 12 of the cover body 10 advantageously allow easy visual inspection of the quality of the joints formed by the solder layer. This allows for faster inspection of the joints and reduces the likelihood of defective joints being overlooked, thereby improving manufacturing efficiency. In some embodiments, the angle between the first main surface 12 of the cover body 10 and each of the plurality of side walls 21a, 21b may be at least 30 degrees, measured from the horizontal direction (i.e., along the direction of the first main surface 12 of the cover body 20). The angle is preferably 90 degrees because the device will be suitable for singulation by common separation methods such as punching out or punching in, and more preferably between 85 degrees and 95 degrees to account for tolerances when using such singulation techniques. The angle of the side walls 21a, 21b applies to all embodiments disclosed herein. The angle may be selected based on, for example, the desired heat dissipation rate from the second heat sink 20. Here and throughout this document, the angle between the first main surface 12 of the cover body 10 and each of the side walls 21a, 21b refers to the exterior angle defined between the first main surface 12 of the cover body 10 and each of the side walls 21a, 21b.

[0065] The second heat sink 20 defines an orientation identification portion 22. The orientation identification portion 22 allows for easy determination of the orientation of the device 2. This is particularly useful during the assembly of the device 2 into an external circuit. In the depicted embodiment, the orientation identification portion is a notch, particularly in the form of a chamfered notch. However, in other embodiments, the orientation identification portion 22 may take any other suitable form. In some embodiments, it is not necessary to provide an orientation identification portion.

[0066] Now reference will be made to Figures 2 to 4 for a discussion of the manufacture of the device 2. First reference is made to Figure 2 . A masking device is used to mask at least a portion of the first main surface 12 of the cover body 10. The masking device is also used to mask (i.e., cover) the plurality of side surfaces 14a, 14b of the cover body 10, as well as the underside of the device (in Figure 2(not visible in the figure). Generally, the lower side of the device faces the first major surface 12 of the cover body 10. The masking device is configured to prevent the dual-functional adhesive from contacting one or more areas of the cover body 10 that it masks. In some embodiments discussed below, the masking device is not required for one or more surfaces or areas of the cover body 10. The geometry of the masking device determines the final geometry of the second heat sink 20, which will be discussed in more detail below. In the case where an orientation identification portion is to be provided, once the first metal layer is formed on the device, the masking device defines the geometry required for the first metal layer to define the orientation identification portion. For example, the masking device may mask a portion of the first major surface 12 of the cover body 10 that corresponds to the coverage area of the orientation identification portion.

[0067] Then, a dual-functional adhesive layer is applied to the first major surface 12 of the cover body 10. The dual-functional adhesive can be a compound suitable for bonding to both the first major surface 12 of the cover body 10 and the heat sink 20. The dual-functional adhesive includes a first functional group capable of reacting and bonding with the first major surface 12 of the cover body 10 and a second functional group capable of reacting and bonding with the heat sink 20 through the metal layer. The compound is preferably an organic polymer. The dual-functional adhesive can be applied by spraying the cover body 10 with the dual-functional adhesive. As an alternative, the device 2 can be immersed in a dual-functional adhesive bath. The masking device prevents the dual-functional adhesive from contacting and thus bonding to one or more areas of the first major surface 12 of the cover body 10 that are masked by the masking device. In some embodiments, as described below, the masking device causes the dual-functional adhesive to be applied in a discontinuous manner. Thus, the dual-functional adhesive layer can be formed by a plurality of separate parts.

[0068] Next, a catalytic layer is applied to the device 2. Specifically, the catalytic layer is applied to the dual-functional adhesive. To apply the catalytic layer to the dual-functional adhesive, the device 2 is immersed in a solution bath containing a catalyst for forming the catalytic layer. The catalyst activates the surface of the dual-functional adhesive layer.

[0069] As an alternative, the catalytic layer can be sprayed onto the device 2 instead of immersing the device in a bath. The catalytic layer does not directly bond to the cover body 10.

[0070] The dual-functional adhesive is bonded only to one or more areas of the cover body 10 allowed by the masking device (i.e., one or more areas not covered by the masking device). As described above, the catalytic layer does not directly bond to the cover body. The catalytic layer bonds to the dual-functional adhesive layer. The catalytic layer forms the basis for the first metal layer. Thus, it will be apparent that the geometry of the masking device (if provided) affects the geometry of the first metal layer. In other words, the geometry of the masking device defines the negative space or empty space of the first metal layer.

[0071] ReferenceFigure 4 , and then a first metal layer 24 is formed. The first metal layer 24 is formed on the catalytic layer. This fixes the first metal layer 24 to the bifunctional adhesive layer and thus to the first main surface 12 of the cover body 10. The first metal layer 24 is formed using electroless plating. Preferably, the contact area between the first metal layer and the cover body 10 is at least 50% of the area of the first main surface 12 of the cover body 10. The contact area between the first metal layer and the cover body 10 can be at least 75% of the area of the first main surface 12 of the cover body 10. The contact area between the first metal layer and the cover body 10 can be selected based on, for example, the desired rate of heat dissipation from the device. This may depend on, for example, the environment in which the device is expected to be used. Here, the area of the first main surface 12 of the cover body 10 refers to the entire area of the first main surface 12 of the cover body 10. In some embodiments, such as Figure 7 shown, the second heat sink 20 can be coupled to one or more of the side surfaces 14a, 14b of the cover body 10. This further increases the surface area of the second heat sink 20, which increases the rate of heat dissipation from the device 2.

[0072] Reference Figure 3 , and then the second heat sink 20 is coupled to the first metal layer (not visible in Figure 3 ). The second heat sink 20 can be coupled to the first metal layer such that the second heat sink 20 extends continuously from the first metal layer, such as by forming the second heat sink 20 by 3D printing. The coverage area of the second heat sink 20 can correspond to the coverage area of the first metal layer. As an alternative, the second heat sink 20 can be formed separately and coupled to the first metal layer by means of an adhesive. A suitable adhesive can be a solder layer provided between the first metal layer and the second heat sink 20. In some embodiments, the second heat sink can be formed by electroplating. In the case where the second heat sink is electroplated or 3D printed onto the first metal layer, it can be said that the second heat sink 20 extends continuously from the first metal layer. 3D printing of the second heat sink 20 is preferred because it allows the second heat sink 20 to be produced faster than in the case of forming the second heat sink 20 by electroplating.

[0073] Since the first metal layer is formed on the first main surface 12 of the cover body 10, the area to which the second heat sink 20 can be coupled is increased compared to a conventional device. This improves the heat dissipation of the device 2, thereby reducing the possibility of the device 2 overheating. In addition, the stress applied to the device 2 during use is better distributed, which reduces the possibility of the device 2 delaminating.

[0074] In the case where the second heat sink 20 is formed separately from the first metal layer and fixed to the first metal layer using a solder layer, the device 2 is then heated. This process is called "reflow".

[0075] Then, the device 2 can be connected to an external circuit in a conventional manner.

[0076] In Figure 3 In the illustrated embodiment, the first major surface 12 of the cover 10 includes a first masking portion 26 and a second masking portion 28. The first metal layer also defines an orientation identification portion 22. The first masking portion 26 and the second masking portion 28 are disposed along opposite portions of the periphery of the first major surface 12. The first masking portion 26 and the second masking portion 28 are adjacent to the respective side surfaces of the cover 10.

[0077] In Figure 5 In an alternative illustrated embodiment, the first major surface 12 of the cover 10 and thus the first metal layer define only the orientation identification portion 22. That is, except for the region defining the orientation identification portion, the first metal layer and the second heat sink 20 extend to the periphery of the first major surface 12 of the cover 10. In this embodiment, the side surfaces 14a, 14b of the cover are still masked by a masking device such that the first metal layer and the second heat sink 20 are not coupled to the side surfaces 14a, 14b. However, this need not be the case for any embodiment.

[0078] In Figure 6 In the illustrated embodiment, the second heat sink 20 includes a plurality of openings 30 (only one opening in the array of openings is labeled in Figure 6 ). The plurality of openings 30 are provided by means of a masking device. When applying the dual-functional adhesive, the masking device masks the regions of the first major surface of the cover 10 (not visible in Figure 6 ) corresponding to the openings 30. However, the plurality of openings 30 can be provided during 3D printing. The plurality of openings 30 are provided in an array. However, the openings can be provided in any suitable manner. The cross-section of each of the plurality of openings 30 is square. However, the cross-section of the opening can be any suitable shape. Each of the plurality of openings 30 extends from the major surface 32 of the second heat sink 20 to the major surface of the cover 10 (not visible in Figure 6 ). The second heat sink 20 provided with the plurality of openings 30 advantageously increases the surface area of the second heat sink 20, which further increases the rate of heat dissipation from the device 2. In other non-depicted embodiments, the coverage area of the second heat sink and thus the coverage area of the first metal layer can define any other suitable discontinuous geometry. For example, the first metal layer and the second heat sink can be constituted by a plurality of strips extending along the first major surface 12 of the cover 10. Herein and throughout this document, the term coverage area associated with a component can be understood as the planned area of the component. Furthermore, herein and throughout this document, a discontinuous coverage area can be understood to mean that one or more surface irregularities, preferably in the form of openings, are formed within the periphery of the coverage area.

[0079] InFigure 7 In the illustrated embodiment, the first metal layer and the second heat sink 20 are fixed to a plurality of side surfaces of the cover body 10. This increases the rate of heat dissipation from the device 2.

[0080] Although specific embodiments of the present invention have been described above, it should be understood that the present invention can be implemented in a manner different from that described. The above description is intended to be illustrative, not restrictive. Therefore, it will be apparent to those skilled in the art that the described present invention can be modified without departing from the scope of the claims set forth below.

Claims

1. A semiconductor device comprising: Lead frame; one or more dies, the one or more dies being secured to the lead frame; a fixture secured to at least one of the one or more dies; a first heat sink secured to the fixture or formed as part of the fixture; a cover at least partially surrounding the leadframe, the one or more dies, and the fixture, wherein a major surface of the cover defines an opening extending to the first heat sink; a first metal layer secured to the first major surface of the cover by means of a bifunctional adhesive; as well as A second heat sink is coupled to the first metal layer. 2 . The semiconductor device according to claim 1 , wherein the first metal layer and the second heat sink define an orientation recognition portion. 3 . The semiconductor device of claim 1 , wherein a footprint of the first metal layer is discontinuous with a footprint of the second heat spreader. 4 . The semiconductor device according to claim 3 , further comprising an opening array, each opening in the opening array extending from a major surface of the second heat sink to the major surface of the cover.

5. A semiconductor device according to any preceding claim, wherein the second heat sink defines a main surface and a plurality of side walls extending from the first metallization layer to the main surface, and wherein the angle between the first main surface of the cover and each of the plurality of side walls is at least 30 degrees, optionally wherein each of the plurality of side walls extends substantially perpendicular to the first main surface of the cover.

6. A semiconductor device according to any preceding claim, wherein the second heat spreader extends continuously from the first metal layer, or wherein The second heat sink is coupled to the first metal layer via an adhesive.

7. The semiconductor device of any preceding claim, wherein the contact area between the first metal layer and the cover is at least 50% of the area of ​​the main surface of the cover.

8. A semiconductor device as claimed in any preceding claim, wherein a footprint of the second heat spreader corresponds to a footprint of the first metal layer.

9. A method comprising: A semiconductor device is provided, the semiconductor device comprising: Lead frame; one or more dies, the one or more dies being secured to the lead frame; a fixture secured to at least one of the one or more dies; a first heat sink secured to the fixture or formed as part of the fixture; a cover at least partially surrounding the leadframe, the one or more dies, and the fixture, wherein an outer surface of the cover defines a major surface, and wherein the cover includes an opening extending to the first heat sink; applying a layer of a bifunctional adhesive to the first major surface of the cover; applying a catalytic layer to the bifunctional adhesive layer; forming a first metal layer on the catalyst layer such that the first metal layer is fixed to the bifunctional adhesive layer; and A second heat sink is coupled to the first metal layer.

10. The method according to claim 8 further includes using a masking device to mask one or more areas of the first main surface of the cover body before applying the dual-functional adhesive, and the masking device is configured to prevent the dual-functional adhesive from adhering to the one or more areas of the first main surface of the cover body masked by the masking device.

11. A method according to claim 10 or claim 11, wherein the geometry of the masking arrangement is such that the first metal layer defines an orientation identifying portion.

12. The method of claim 10, wherein the geometry of the masking device causes the dual-function adhesive to be applied to the first major surface of the cover in a discontinuous manner.

13. The method of any one of claims 9 to 12, wherein the second heat sink is coupled to the first metal layer by printing the second heat sink onto the first metal layer; optionally, wherein The second metal layer is formed by electroplating.

14. The method of any one of claims 9 to 12, wherein the second heat sink is coupled to the first metal layer by means of an adhesive.

15. The method according to any one of claims 9 to 14, wherein the first metal layer is formed using electroless plating.

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