Grounding lead in quad flat package

Abstract

The present disclosure relates to ground leads in quad flat packages. An example leadframe, leadframe package, and method for grounding leads in a leadframe package are provided. The example leadframe includes an electrically grounded tiebar, a plurality of leads, an insulative adhesive material, and a conductive material. The plurality of leads includes at least a ground lead and an intermediate lead, where the intermediate lead is positioned between the ground lead and the tiebar. The insulative adhesive material is attached to a surface of the intermediate lead. The conductive material is positioned on a surface of the insulative adhesive material opposite the intermediate lead, where the conductive material electrically connects the ground lead to the tiebar.

Description

[0001] Cross-reference to related applications

[0002] This application claims the benefit of U.S. Provisional Patent Application No. 63 / 782,164, filed April 2, 2025, entitled “GROUNDED LEADS IN A QUAD-FLATPACKAGE,” the entire contents of which are incorporated herein by reference. Technical Field

[0003] Embodiments of this disclosure generally relate to lead frames in quad flat packages, and more specifically, to ground leads of lead frames in quad flat packages. Background Technology

[0004] Many electronic systems utilize printed circuit boards (PCBs) to support and connect various electrical components of the electrical system. For example, a PCB may include a rigid structure with multiple mounting areas configured to receive various electrical components. A PCB may also include conductive traces or paths to enable electrical connections between various electrical components. PCBs typically receive surface-mount and / or receptacle-type electrical components, including various integrated circuits (ICs).

[0005] An example structure used to connect an IC to a PCB is the leadframe package. A leadframe package is a surface mount technology that provides structural support for the IC, protects it from environmental factors, and provides electrical connection between the IC and the PCB without through-holes. Conductive protrusions (leads) form the electrical connection between the IC and the PCB in the leadframe package. In some examples, one or more leads of the quad flat package may need to be electrically grounded.

[0006] The applicant has identified numerous technical challenges and difficulties associated with the ground lead in a quad flat package. Through effort, ingenuity, and innovation, the applicant has solved the problems associated with the ground lead in a quad flat package by developing a solution embodied in this disclosure, which is described in detail below. Summary of the Invention

[0007] Various embodiments relate to an example leadframe, a leadframe package, and a method for grounding leads in the leadframe package.

[0008] An example lead frame is provided. The example lead frame includes an electrically grounded tie rod, a plurality of leads, an insulating adhesive material, and a conductive material. The plurality of leads include at least a ground lead and an intermediate lead, wherein the intermediate lead is positioned between the ground lead and the tie rod. The insulating adhesive material is attached to a surface of the intermediate lead. The conductive material is positioned on a surface of the insulating adhesive material opposite to the intermediate lead, wherein the conductive material electrically connects the ground lead to the tie rod.

[0009] In some embodiments, the lead frame further includes die pads, wherein the die pads are electrically grounded.

[0010] In some embodiments, the tie rod is electrically connected to the die pad.

[0011] In some embodiments, the tie rod is substantially parallel to the plurality of leads.

[0012] In some embodiments, the insulating adhesive material is a polyimide film.

[0013] In some embodiments, the conductive material is an adhesive.

[0014] In some embodiments, the conductive material is copper foil strip.

[0015] In some embodiments, the lead frame is integrated into a quad flat package.

[0016] An example method for grounding a grounding lead in a leadframe enclosure is also provided. This example method includes providing a leadframe. The leadframe includes an electrically grounded tie rod, a plurality of leads, an insulating adhesive material, and a conductive material. The plurality of leads includes at least a grounding lead and an intermediate lead, wherein the intermediate lead is positioned between the grounding lead and the tie rod. The example method also includes attaching the insulating adhesive material to a surface of the intermediate lead and positioning the conductive material on a surface of the insulating adhesive material opposite to the intermediate lead, wherein the conductive material electrically connects the grounding lead to the tie rod.

[0017] In some embodiments, the lead frame further includes die pads, wherein the die pads are electrically grounded.

[0018] In some embodiments, the tie rod is electrically connected to the die pad.

[0019] In some embodiments, the tie rod is substantially parallel to the plurality of leads.

[0020] In some embodiments, the insulating adhesive material is a polyimide film.

[0021] In some embodiments, the conductive material is an adhesive.

[0022] In some embodiments, the conductive material is copper foil strip.

[0023] In some embodiments, the lead frame is integrated into a quad flat package.

[0024] An example leadframe package is also provided. This example leadframe package includes an electrically grounded die pad, an integrated circuit attached to the die pad, and a leadframe. The leadframe includes a tie rod electrically connected to the die pad, a plurality of leads, an insulating adhesive material, and a conductive material. The plurality of leads include at least a ground lead; and an intermediate lead, wherein the intermediate lead is positioned between the ground lead and the tie rod. The insulating adhesive material is attached to a surface of the intermediate lead. The conductive material is positioned on a surface of the insulating adhesive material opposite to the intermediate lead, wherein the conductive material electrically connects the ground lead to the tie rod.

[0025] In some embodiments, the leadframe package further includes bonding wires that electrically connect intermediate leads to the integrated circuit.

[0026] In some embodiments, the insulating adhesive material is a polyimide film.

[0027] In some embodiments, the leadframe package includes a quad flat package. Attached Figure Description

[0028] The description will now be made with reference to the accompanying drawings. The components illustrated in the drawings may or may not be present in some embodiments described herein. Some embodiments may include fewer (or more) components than those shown in the drawings of exemplary embodiments according to this disclosure.

[0029] Figure 1 A perspective view of an example lead frame package according to an example embodiment of the present disclosure is depicted.

[0030] Figure 2 A cross-sectional view of an example lead frame package according to an example embodiment of the present disclosure is depicted.

[0031] Figure 3 A top view of the grounding lead of an example lead frame according to an example embodiment of the present disclosure is depicted.

[0032] Figure 4 A cross-sectional view of a grounding lead according to an exemplary embodiment of the present disclosure is depicted.

[0033] Figure 5 A manufacturing flowchart depicts an example process for grounding leads in a leadframe package prior to downsetting, according to an example embodiment of the present disclosure.

[0034] Figure 6 A manufacturing flowchart depicts an example process for grounding leads in a leadframe package after sinking, according to an example embodiment of the present disclosure.

[0035] Figure 7 An example process for grounding the leads of a lead frame according to an example embodiment of the present disclosure is described. Detailed Implementation

[0036] Example embodiments will now be described more fully with reference to the accompanying drawings, which illustrate some, but not all, embodiments of the invention disclosed herein. In fact, embodiments of the invention may be embodied in many different forms and should not be construed as limited to the embodiments set forth herein; rather, these embodiments are provided so that the disclosure may meet applicable legal requirements. Similar numerals always refer to similar elements.

[0037] Overview

[0038] Various example embodiments address technical problems associated with grounding leads in leadframe packages (such as quad flat packages). As those skilled in the art to which this disclosure pertains will understand, there are numerous example scenarios in which electrical systems can benefit from improved techniques for individually grounding leads in leadframe packages.

[0039] For example, many electronic systems utilize printed circuit boards (PCBs) to support and connect various electrical components of the electrical system. A PCB may include a rigid structure having multiple mounting areas configured to receive various electrical components. A PCB may also include conductive traces or paths to enable electrical connections between the various electrical components. PCBs typically receive surface-mount and / or socket-type electrical components, including various integrated circuits (ICs) enclosed in surface-mount and / or socket-type packages.

[0040] An example structure used to connect an IC to a PCB is the leadframe package. A leadframe package is a surface mount technology that provides structural support for the IC, protects it from environmental factors, and provides electrical connection between the IC and the PCB without through-holes. Conductive protrusions (leads) form the electrical connection between the IC and the PCB within the leadframe package. In some examples, one or more leads of the quad flat package may be electrically grounded. Grounding the leads of the leadframe package can be critical for the operation of the IC and / or the leadframe package itself.

[0041] In some previous examples, the grounding lead could be directly connected to the die pads of the leadframe package. However, generally, the die pads are located much lower (e.g., on a different plane) compared to the inner portion of the leadframe package's leads. Therefore, for example, it may be difficult to directly connect the inner leads to the die pads, which may require grounding a separate lead to the recessed die pads after manufacturing. Furthermore, the requirements for the grounding lead may vary depending on the application. From a manufacturing cost perspective, directly connecting the grounding lead to the die pads can be very expensive, especially when there are many customization variations.

[0042] In other examples, a ground bus may extend perpendicularly to the inner leads between them and the IC. Any inner leads to be grounded can be attached to the ground bus. However, the ground bus may occupy the area between the inner leads and the IC, increasing the size of the leadframe package. Additionally, the length of the bonding wires to reach the IC may need to be increased, leading to an increase in the overall package cost.

[0043] The various example embodiments described herein utilize various techniques to electrically ground leads within a leadframe package. For example, in some embodiments, an insulating adhesive material is attached to the surface of each lead (e.g., an intermediate lead) between the lead to be grounded (e.g., a ground lead) and an electrically grounded conductor (e.g., a tie rod). Once the insulating adhesive material is attached, a conductive material is attached to the top surface of the insulating adhesive material. Thus, the insulating adhesive material provides electrical insulation between the intermediate lead and the conductive material. Applying the insulating adhesive material to the intermediate lead allows the intermediate lead to continue transmitting electrical signals between the IC and the electrical system, while electrically grounding the ground lead to the tie rod. In some embodiments, the conductive material comprises an adhesive material, such as copper foil tape, attached to the top surface of the insulating adhesive material.

[0044] As a result of the exemplary embodiments described herein, the cost and complexity of grounding leads within a leadframe package can be significantly reduced. Additionally, the area required for grounding leads within the leadframe package can be reduced. Furthermore, the concepts described herein can provide flexibility in grounding leads within the leadframe package at different points in the manufacturing process.

[0045] Exemplary systems and devices

[0046] Now for reference Figure 1 Example Quad Flat Package 100 is provided. Figure 1 The tetrahedral flat package 100 depicted represents an example embodiment of a leadframe package. For example... Figure 1As depicted, the Quad Flat Package 100 includes a package molding 102 that protects the internal electrical components of the Quad Flat Package 100. Additionally, the Quad Flat Package 100 includes a plurality of leads 104 configured to electrically connect the Quad Flat Package 100 to an electrical system.

[0047] Quad Flat Package 100 is a type of leadframe package used to provide surface mounting for IC dies. Quad Flat Package 100 includes leads 104 extending from all four sides. Due to its compact design and efficient heat dissipation, Quad Flat Package 100 is commonly used in electronic devices. The leads 104 of Quad Flat Package 100 are typically thin and closely spaced, making it ideal for high-density electrical systems. Quad Flat Package 100 can also include thin quad flat packages and ultra-thin quad flat packages.

[0048] like Figure 1 As depicted, the Quad Flat Package 100 includes a package molding 102. The package molding 102 comprises any non-conductive material configured to protect the internal components of the Quad Flat Package 100 from the surrounding environment, such as an IC. In some embodiments, the Quad Flat Package 100 may be mounted within an electrical system in harsh environments (e.g., high temperatures, low temperatures, exposure to dust, water, dirt, sand, etc.). In such an example, the Quad Flat Package 100 can be used to protect an IC from harsh environments during operation. In a non-limiting example, the Quad Flat Package 100 may be deployed with an electrical system in a part of an automotive vehicle (e.g., engine, chassis, drive system, etc.). The package molding 102 may include resin, polymer plastic, or other insulating materials.

[0049] like Figure 1 As depicted, the package molding 102 is formed to define the external dimensions of the quad flat package 100. Conductive leads 104 protrude from the surface of the quad flat package to provide a conductive path from an external electrical system to electrical components (e.g., ICs) of the quad flat package 100.

[0050] like Figure 1As further described, the Quad Flat Package 100 includes a plurality of conductive leads 104. The conductive leads 104 are any conductive protrusions, wires, or surfaces configured to provide electrical connections to internal components (e.g., ICs) of the Quad Flat Package 100. In some embodiments, the conductive leads 104 may comprise copper, copper alloys, iron, tin, aluminum, or other similar conductive materials. The conductive leads 104 may be electrically coupled to different electrical components of the Quad Flat Package 100. For example, one conductive lead 104 may be electrically coupled to a clock, another may be electrically coupled to a reset signal, a third conductive lead may be electrically coupled to an output signal of an internal IC, a fourth conductive lead 104 may include an electrical ground, and so on. The conductive leads 104 may be positioned to align with one or more conductive pads on a mounting surface (e.g., a PCB) of an electrical system. The conductive leads 104 enable the Quad Flat Package 100 to be electrically coupled to an electrical system using surface mount technology, socket mount technology, or other similar mounting techniques.

[0051] Now for reference Figure 2 A cross-sectional view of an example quad flat package 200 is provided. Figure 2 As depicted, the example Quad Flat Package 200 includes an IC die 206 attached to a die pad 202 via die attachment material 204. The Quad Flat Package 200 also includes a plurality of leads 104 partially electrically connected to the IC die 206 via internal leads 208 of the conductive leads 104. A package molding 102 provides protection for the IC die 206 and other internal components while defining the external dimensions of the Quad Flat Package 200.

[0052] like Figure 2 As depicted, the example quad flat package 200 includes an IC die 206. The IC die 206 (e.g., a semiconductor die) is any circuit system comprising semiconductor material that performs one or more functions using electrical components. The IC die 206 may include a processor, a reconfigurable structure, passive electrical components, active electrical components, memory, communication circuitry, and / or any other electrical components required to perform the functions of the IC die 206. The IC die 206 is also configured to receive and / or generate one or more electrical signals. One or more electrical signals are transmitted between the IC die 206 and the electrical system via one or more IC contacts on the surface of the IC and via corresponding conductive leads 104 electrically connected to the IC die 206 by conductive bonding wires 210. Figure 2 As depicted, one or more conductive leads 104 provide conductive paths to interface with the IC die 206 from an external system.

[0053] like Figure 2As depicted, the example quad flat package 200 includes a die pad 202. The die pad 202 comprises any thermally conductive material configured to transfer heat from the leadframe package 100 to a fluid in the surrounding environment (e.g., air, liquid coolant) and / or a heat dissipation area of ​​the mounting surface (e.g., a PCB). The die pad 202 may include copper, aluminum, aluminum alloy, or other similar thermally conductive materials. The materials constituting the die pad 202 can depend on the application, thermal intensity, manufacturing method, budget, and other factors. A die attachment material 204 is any bonding material configured to create a thermally conductive interface between the IC die 206 and the die pad 202. The die attachment material 204 enables heat transfer from the IC die 206 to the die pad 202. The die pad 202 is also thermally connected to a thermally conductive surface 110. The thermally conductive surface 110 is designed to interface with a heat dissipation area of ​​the mounting interface. The thermally conductive surface 110 enables efficient heat transfer from the IC die 206 to the surrounding environment.

[0054] like Figure 2 As depicted, the example quad flat package 200 includes multiple bonding wires 210. The conductive bonding wires 210 electrically connect IC contacts on IC die 206 to corresponding internal lead portions 208 of conductive leads 104. The conductive bonding wires 210 enable the transmission of electrical signals from IC die 206 to external electrical systems. The bonding wires 210 can include any conductive material, such as gold, aluminum, copper, etc. The bonding wires 210 can be created using wire drawing or other similar techniques. Common bonding wire techniques include ball joints and wedge joints.

[0055] Now for reference Figure 3 An example lead frame 300 including a ground lead 304 is provided according to one or more example embodiments of the present disclosure. For example... Figure 3 As depicted, the lead frame 300 includes a plurality of internal leads 208 extending toward the die pad 202. The lead frame 300 also includes an electrically grounded tie rod 302 connected to the die pad 202. An insulating adhesive material 308 is attached to the surface of a plurality of intermediate leads 306 positioned between the tie rod 302 and the grounded lead 304. Additionally, a conductive material 310 is placed on the surface of the insulating adhesive material 308 such that the insulating adhesive material 308 electrically insulates the conductive material 310 from each intermediate lead 306, while the conductive material 310 electrically connects the grounded lead 304 to the electrically grounded tie rod 302.

[0056] like Figure 3 As depicted, the example leadframe 300 includes a plurality of internal leads 208, tie rods 302, and die pads 202. The internal leads 208 include leads (e.g., as shown in the image) within a package molding (e.g., package molding 102). Figures 1-2The conductive portion of lead 104 (as depicted in the diagram). Figure 3 As depicted, the leadframe 300 includes a plurality of internal leads 208 extending from the outer edge of the quad flat package toward the die pad 202. Figure 2 As further depicted, each internal lead 208 is substantially parallel, such that adjacent internal leads 208 do not intersect as they extend from the outside of the quad flat package toward the internal die pad 202. The internal leads 208 provide a conductive path from inside the quad flat package to the external leads.

[0057] Internal leads 208 include a ground lead 304. The ground lead 304 is any internal lead 208 that can be electrically grounded to support the functionality of a quad flat package and / or an IC die. Although only one ground lead 304 is depicted, the lead frame 300 may include multiple ground leads 304. Each ground lead 304 should be electrically connected to a ground conductor for proper operation.

[0058] like Figure 3 As further depicted, tie rod 302 extends parallel to the inner lead 208 from the outer portion of lead frame 300 to physically and electrically connect to die pad 202. Tie rod 302 includes any conductive portion of lead frame 300 designed to provide structural support for die pad 202 of lead frame 300 by attaching between the outer portion of lead frame 300 and die pad 202. Tie rod 302 and die pad 202 are further electrically grounded conductors. Therefore, attaching conductive material (e.g., conductive material 310) to tie rod 302 electrically grounds any electrically connected components.

[0059] In some embodiments, one or more intermediate leads 306 may be positioned between the ground lead 304 and the tie rod 302. The intermediate lead 306 includes any internal leads 208 positioned between the ground lead 304 and the tie rod 302.

[0060] Despite from Figure 3 While not immediately obvious, the die pad 202 is recessed relative to the internal lead 208. Therefore, the die pad 202 lies on a different plane than the internal lead 208. Due to the recessed distance between the die pad 202 and the internal lead 208, it may be difficult to directly electrically connect the individual internal lead 208 to the die pad 202. Therefore, to electrically ground the ground lead 304, a conductive path can be established between the ground lead 304 and the tie rod 302.

[0061] like Figure 3As further depicted, the example lead frame 300 utilizes an insulating adhesive material 308 to electrically insulate the intermediate leads 306 from the conductive material 310. The insulating adhesive material 308 may include any electrically insulator that can adhere to the surface of the inner leads 208. In a non-limiting example, the insulating adhesive material 308 may include a polyimide film. The insulating adhesive material 308 may be attached to the surface of one or more consecutive intermediate leads 306. The insulating adhesive material 308 enables the intermediate leads 306 to continue transmitting electrical signals between the IC die and the leads without interference or interruption from the conductive material 310. (See also: [link to relevant documentation]). Figure 5 As described, in some embodiments, the insulating adhesive material 308 may be applied by the supplier before the strips of the lead frame are cut. (See also: Regarding...) Figure 6 As described, in some embodiments, the insulating adhesive material 308 may be applied by the lead frame customer after the lead frame 300 has been lowered.

[0062] like Figure 3 As further described herein, conductive material 310 is positioned on top of insulating adhesive material 308 (on the surface of insulating adhesive material 308 opposite to the intermediate lead 306) and electrically connects ground lead 304 to electrically grounded tie rod 302. As described herein, conductive material 310 includes any conductive material that can be positioned on top of insulating adhesive material 308. In some embodiments, conductive material 310 may be narrower than insulating adhesive material 308. In some embodiments, conductive material 310 may be an adhesive material that can be attached to the surface of insulating adhesive material 308. For example, in some embodiments, conductive material 310 may include copper foil strip.

[0063] Now for reference Figure 4 A cross-sectional view of the lead frame portion 400 is depicted. (See figure.) Figure 4 As depicted, the lead frame portion 400 includes a ground lead 304 and a tie rod 302 separated by a plurality of intermediate leads 306. Each intermediate lead 306 can be configured to transmit electrical signals between the IC die and external leads. Figure 4 As further described, an insulating adhesive material 308 is placed on the surface (e.g., top surface 306a) of each intermediate lead 306 between the grounding lead 304 and the tie rod 302. A conductive material 310 is placed on top of the insulating adhesive material 308 (e.g., top surface 308a) and electrically connects the grounding lead 304 to the electrically grounded tie rod 302. The insulating adhesive material 308 electrically insulates the intermediate leads 306 from the conductive material 310, allowing the intermediate leads 306 to continue transmitting and receiving signals.

[0064] Exemplary methods

[0065] Now for reference Figure 5 An example manufacturing flow diagram is provided, depicting an example process 500 for grounding leads (e.g., ground lead 304) in a leadframe package (e.g., quad flat package 100) before sinking.

[0066] like Figure 5 As depicted, a blank lead frame is provided at frame 502. The blank lead frame comprises a flat plate of conductive material, such as a copper alloy, and is typically square or rectangular in shape.

[0067] At frame 504, stamping and etching processes are performed. Stamping is a manufacturing process that shapes a blank leadframe sheet into a leadframe by pressing a blank leadframe into a die. In some embodiments, a weight plate containing a stamping die assembly can be stamped onto the blank leadframe sheet to define the structure of the leadframe. Stamping can produce a leadframe with precise dimensions and shape.

[0068] Etching is a manufacturing process that uses chemicals to create precise patterns on a stamped leadframe sheet. In some embodiments, etching may include applying a photoresist layer to a blank and / or stamped leadframe, aligning a photomask with the desired pattern over the photoresist, exposing the photoresist to ultraviolet light in the desired pattern, exposing portions of the leadframe to be etched, and immersing the leadframe in a chemical etching solution. The etching process can define precise shapes and structures within the leadframe.

[0069] At frame 506, a plating process is performed. Plating is a process involving the application of a conductive coating, such as nickel, silver, gold, tin, palladium, etc., to the lead frame. Plating can improve the adhesion of wire bonding, encapsulation molding, and die attachment materials. Plating can also improve the adhesion of insulating adhesive materials (e.g., insulating adhesive material 308). The plating process may be referred to as electroplating.

[0070] At frame 508, an insulating adhesive material is applied. One or more strips of insulating adhesive material may be applied to any intermediate inner lead (e.g., intermediate lead 306) between the grounding lead (e.g., grounding lead 304) and the tie rod (e.g., tie rod 302). In some embodiments, intermediate leads that are also grounding leads may be skipped, such that no insulating adhesive material is applied. The insulating adhesive material may be applied automatically, for example by a robot or machine configured to apply the insulating adhesive material to the intermediate leads. Although depicted as a continuous strip, in some embodiments, the insulating adhesive material may comprise discrete portions placed on the surface of each intermediate lead.

[0071] At frame 510, a conductive material (e.g., conductive material 310) can be applied to the surface of the insulating adhesive material opposite to the intermediate lead, and the grounding lead can be electrically attached to the tie rod. Thus, the conductive material can create an electrical connection between the grounding lead and the tie rod, thereby electrically grounding the grounding lead. In some embodiments, the conductive material can extend across multiple grounding leads and insulating adhesive materials to electrically ground multiple grounding leads. In some embodiments, the conductive material can be an adhesive material, such as copper foil tape. The conductive material can be applied automatically, for example by a robot or machine configured to apply the conductive material to the surface of the insulating adhesive material on the intermediate lead.

[0072] At frame 512, a dip and strip cutting process is performed. The dip process is the process of pushing a portion of the leadframe's die pad (e.g., die pad 202) downward relative to the internal leads of the leadframe, thereby properly aligning the leadframe with the IC die (e.g., IC die 206) attached to the die pad. The strip cutting process is the process of separating the leadframe into individual packages. Strip cutting can be performed by a mechanical dicing machine.

[0073] Therefore, as Figure 5 As described, the attachment of insulating adhesive material and conductive material for connecting the grounding lead to the electrical ground can occur during the manufacturing process, such as before the lead frame is sunk and the lead frame is cut into strips.

[0074] Now for reference Figure 6 An example manufacturing flow diagram is provided, depicting an example process 600 of grounding leads (e.g., ground lead 304) in a leadframe package (e.g., quad flat package 100) after sinking. Figure 6 As depicted, in some embodiments, the grounding lead may be grounded after the manufacturer has lowered the lead frame, for example, at the customer site.

[0075] At frame 602, a recessed lead frame is provided. The recessed lead frame has undergone a recessing process during which a portion of the die pads (e.g., die pad 202) of the lead frame is pushed downward relative to the internal leads of the lead frame, so that the lead frame is properly aligned with the IC die (e.g., IC die 206) attached to the die pads.

[0076] At frame 604, an insulating adhesive material (e.g., insulating adhesive material 308) is applied to insulate any intermediate leads from the conductive material.

[0077] At frame 606, a conductive material (e.g., conductive material 310) may be applied to electrically connect the grounding lead to the electrically grounded tie rod. The conductive material is applied to the surface of the insulating adhesive material opposite to the intermediate lead, such that the intermediate lead is electrically insulated from the conductive material. In some embodiments, the conductive material may be applied automatically, for example by a robot or machine configured to apply the conductive material to the surface of the insulating adhesive material on the intermediate lead.

[0078] Therefore, as Figure 6 The attachment of insulating adhesive material and conductive material for connecting the grounding lead to the electrical ground, as described herein, can occur at the customer site after the lead frame is lowered and cut into strips.

[0079] Now for reference Figure 7 An example process 700 is provided for grounding the leads (e.g., ground lead 304) of a leadframe (e.g., leadframe 300). At block 702, a leadframe is provided including an electrically grounded tie rod (e.g., tie rod 302) and a plurality of leads (e.g., inner leads 208). The plurality of leads includes at least a ground lead and an intermediate lead (e.g., intermediate lead 306). The intermediate lead is positioned between the ground lead and the tie rod. In some embodiments, the leadframe may have been sunk and stripped such that the die pad (e.g., die pad 202) is in a different plane from the plurality of leads. In some embodiments, the leadframe may be provided prior to performing the sunk and strip-cutting process.

[0080] At frame 704, an insulating adhesive material (e.g., insulating adhesive material 308) is attached to the surface of the intermediate lead (e.g., top surface 306a). In some embodiments, the insulating adhesive material can be applied automatically, for example by a robot or machine configured to apply the insulating adhesive material to the intermediate lead.

[0081] At frame 706, a conductive material (e.g., conductive material 310) is positioned on the surface of the insulating adhesive material opposite to the intermediate lead (e.g., top surface 308a). The conductive material electrically connects the ground lead to the tie rod. The conductive material can be positioned automatically, for example by a robot or machine configured to apply the conductive material to the surface of the insulating adhesive material on the intermediate lead. In some embodiments, the conductive material may include an adhesive material to which the conductive material is attached to the top surface of the insulating adhesive material. Positioning the conductive material that electrically connects the ground lead and the tie rod on the top surface of the insulating adhesive material allows an electrical connection between the tie rod and the ground lead to be established without interrupting signal flow through each intermediate lead.

[0082] in conclusion

[0083] While this detailed description has set forth some embodiments of the invention, the appended claims cover other embodiments of the invention according to various modifications and improvements, different from the described embodiments. For example, those skilled in the art will recognize that these principles can be applied to any leadframe package where the leads can be grounded during operation.

[0084] Within the appended claims, unless the specific terms “means for…” or “steps for…” are used in a given claim, the claims are not intended to be interpreted in accordance with paragraph 6 of 35 U.S.SC §112.

[0085] The use of broader terms such as “comprising,” “including,” and “having” should be understood to provide support for narrower terms such as “consisting of,” “generally consisting of,” and “substantially consisting of.” The use of terms such as “optionally,” “may,” “possibly,” or “possibly” with respect to any element of the embodiments means that the element is not essential, or alternatively, that the element is essential, both of which are within the scope of the embodiments(s). Furthermore, examples are provided for illustrative purposes only and are not intended to be exclusive.

Claims

1. A lead frame, comprising: A tie rod, wherein the tie rod is electrically grounded; Multiple leads, including at least: Grounding lead; and An intermediate lead, wherein the intermediate lead is positioned between the grounding lead and the tie rod; Insulating adhesive material is attached to the surface of the intermediate lead; and A conductive material is positioned on the surface of the insulating adhesive material opposite to the intermediate lead; The conductive material electrically connects the grounding lead to the tie rod.

2. The lead frame according to claim 1 further includes die pads, wherein, The die pad is electrically grounded.

3. The lead frame according to claim 2, wherein, The tie rod is electrically connected to the die pad.

4. The lead frame according to claim 1, wherein, The tie rod is substantially parallel to the plurality of leads.

5. The lead frame according to claim 1, wherein, The insulating adhesive material is a polyimide film.

6. The lead frame according to claim 1, wherein, The conductive material is an adhesive.

7. The lead frame according to claim 6, wherein, The conductive material is copper foil strip.

8. The lead frame according to claim 1, wherein, The lead frame is integrated into a quad flat package.

9. A method for grounding a ground lead in a leadframe package, the method comprising: A lead frame is provided, the lead frame comprising: Tie rod, wherein the tie rod is electrically grounded; and Multiple leads, including at least: The grounding lead; and An intermediate lead, wherein the intermediate lead is positioned between the grounding lead and the tie rod; Attach insulating adhesive material to the surface of the intermediate lead; and A conductive material is positioned on the surface of the insulating adhesive material opposite to the intermediate lead, wherein the conductive material electrically connects the ground lead to the tie rod.

10. The method according to claim 9, wherein, The lead frame also includes a die pad, wherein the die pad is electrically grounded.

11. The method according to claim 10, wherein, The tie rod is electrically connected to the die pad.

12. The method according to claim 9, wherein, The tie rod is substantially parallel to the plurality of leads.

13. The method according to claim 9, wherein, The insulating adhesive material is a polyimide film.

14. The method according to claim 9, wherein, The conductive material is an adhesive.

15. The method according to claim 14, wherein, The conductive material is copper foil strip.

16. The method according to claim 9, wherein, The lead frame is integrated into a quad flat package.

17. A leadframe package, comprising: The die pad is electrically grounded; Integrated circuit, attached to the die pad; Lead frame, including: Tie rod, wherein the tie rod is electrically connected to the die pad; and Multiple leads, including at least: Grounding lead; and An intermediate lead, wherein the intermediate lead is positioned between the grounding lead and the tie rod; Insulating adhesive material is attached to the surface of the intermediate lead; and A conductive material is positioned on the surface of the insulating adhesive material opposite to the intermediate lead; The conductive material electrically connects the grounding lead to the tie rod.

18. The lead frame package according to claim 17, further comprising: A bonding wire is used to electrically connect the intermediate lead to the integrated circuit.

19. The lead frame package according to claim 17, wherein, The insulating adhesive material is a polyimide film.

20. The lead frame package according to claim 17, wherein, The leadframe package includes a quad flat package.

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