Lead frame, package, and method of manufacturing lead frame
By using a stacked three-dimensional leadframe structure and adhesive bonding technology, the signal and heat dissipation limitations of traditional leadframe packaging are solved, achieving higher efficiency and lower cost semiconductor packaging.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- CYNTEC
- Filing Date
- 2025-05-26
- Publication Date
- 2026-05-22
AI Technical Summary
Traditional leadframe packaging has limitations in terms of signal integrity, manufacturing cost, and heat dissipation, making it difficult to meet the demands of electronic devices for higher efficiency, smaller size, and cost-effectiveness.
A stacked three-dimensional leadframe structure is adopted, in which the first leadframe and the second leadframe are vertically joined to form multiple signal transmission paths and heat dissipation paths. Adhesive materials are used for bonding, and surface etching and surface treatment processes are combined to enhance the performance of the leadframe.
It improves signal transmission quality, enhances heat dissipation, and reduces manufacturing costs, meeting the demands of electronic devices for high efficiency and miniaturization.
Smart Images
Figure CN122074008A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to a semiconductor package. Background Technology
[0002] Leadframes have long been a traditional and widely used interconnect technology in semiconductor packaging, providing electrical connections and mechanical support for the die. However, with the increasing demand for higher performance, smaller size, and cost-effectiveness in electronic devices, the limitations of traditional leadframe-based packaging are becoming more apparent, especially in terms of signal integrity, manufacturing cost, and heat dissipation. Summary of the Invention
[0003] Therefore, one of the objectives of this disclosure is to provide a three-dimensional leadframe and related semiconductor package that can provide a better signal transmission path, better heat dissipation, and reasonable manufacturing cost, thereby solving the problems described in the prior art.
[0004] In one embodiment, a package is disclosed comprising a die, a first leadframe, and a second leadframe, wherein the first leadframe and the second leadframe are stacked and bonded together using an adhesive material to form a final leadframe; wherein the die is bonded to the final leadframe.
[0005] In one embodiment, a lead frame is disclosed, comprising a first lead frame and a second lead frame, wherein the first lead frame and the second lead frame are stacked and bonded together by using an adhesive material to form a final lead frame.
[0006] In one embodiment, a method for manufacturing a lead frame is disclosed, comprising: manufacturing a first lead frame; manufacturing a second lead frame; and stacking and joining the first lead frame and the second lead frame to form a final lead frame as the lead frame. Attached Figure Description
[0007] Figure 1A This is a schematic diagram of a semiconductor package according to an embodiment of the present disclosure.
[0008] Figure 1B This is a top view of a first conductor frame according to an embodiment of the present disclosure.
[0009] Figure 1C This is a schematic diagram of a first guide frame and a second guide frame according to an embodiment of the present disclosure.
[0010] Figure 2 This is a schematic diagram of a portion of a final conductor frame including the first conductor frame and the second conductor frame according to a first embodiment of the present disclosure.
[0011] Figure 3This is a schematic diagram of a portion of a final conductor frame including the first conductor frame and the second conductor frame according to a second embodiment of the present disclosure.
[0012] Figure 4 This is a schematic diagram of a portion of a final conductor frame including the first conductor frame and the second conductor frame according to a third embodiment of the present invention.
[0013] Figure 5 This is a schematic diagram of a wire frame with a keyhole according to a first embodiment of the present invention.
[0014] Figure 6 A flowchart illustrating the manufacture of a final conductor frame comprising a first conductor frame and a second conductor frame according to an embodiment of the present invention.
[0015] The attached figures are labeled as follows:
[0016] 100: Semiconductor Packaging
[0017] 110: Grain
[0018] 152, 154, 156: Pins
[0019] 162, 172, 174, 176, 178: Part of the second conductor frame
[0020] 600, 602, 604, 606: Steps Detailed Implementation
[0021] Figure 1A This is a schematic diagram of a semiconductor package 100 according to an embodiment of the present disclosure. Figure 1A As shown, the semiconductor package 100 includes a first leadframe, a second leadframe, and a die 110. In this embodiment, the first leadframe and the second leadframe are joined together in a perpendicular direction (here, "perpendicular direction" refers to a direction perpendicular to the plane of the paper), meaning that the first leadframe and the second leadframe are stacked to form a final leadframe (i.e., a three-dimensional leadframe) for subsequent assembly of the die 110. In this embodiment, the final leadframe, including the first leadframe and the second leadframe, serves as the physical and electrical interface between the die 110 and external circuitry on a printed circuit board (PCB) or other system. The pins on the four sides of the first leadframe are used to transmit signals from the die 100 to the external circuitry, or vice versa.
[0022] In this embodiment, both the first and second leadframes are bonded together at the leadframe manufacturing plant using an adhesive material, which can be solder paste, epoxy paste, film, pillar, etc. Furthermore, the adhesive material can be conductive or non-conductive. In one embodiment, a portion of the first leadframe is bonded to a portion of the second leadframe using a conductive adhesive material, while another portion of the first leadframe is bonded to another portion of the second leadframe using a non-conductive adhesive material.
[0023] In this embodiment, because the first and second conductor frames are joined together vertically, the conductor frame will have more signal transmission paths. That is, in addition to the traditional transmission paths in the planar direction, Figure 1A Multiple vertical signal transmission paths also exist within the package, thereby allowing for adjustment or improvement of signal transmission quality. Furthermore, the final lead frame, which includes the first lead frame and the second lead frame, has additional heat dissipation paths, thereby improving the heat dissipation of the semiconductor package 100.
[0024] It should be noted that, Figure 1A The shapes of the first and second lead frames shown are merely illustrative and not intended to limit the scope of this disclosure. In other embodiments, the first and second lead frames may have any suitable shape, provided they can be stacked and joined together.
[0025] Figure 1B This is a top view of a first conductor frame according to an embodiment of the present disclosure. Figure 1B As shown, considering the influence of surface mount technology (SMT) and design rules, the first leadframe is designed with a symmetrical structure and pins with a fixed spacing, such as... Figure 1B As shown, the first conductor frame has symmetrical pins. However, in this design, power / ground wiring cannot pass through, for example... Figure 1B Pins 152, 154, and 156, as shown, leave some space unusable for heat dissipation or signal transmission. To improve the limitations of the first leadframe in signal transmission and heat dissipation, the second leadframe in this embodiment provides additional signal transmission and heat dissipation paths.
[0026] refer to Figure 1CA portion 162 of the second leadframe is directly connected to the die 110, allowing portion 162 to receive the heat generated by the die 110 during operation (part of the heat is received by the first leadframe), thereby improving the heat dissipation of the leadframe. Furthermore, portions 172, 174, 176, and 178 of the second leadframe can provide signal transmission paths for the first leadframe, addressing the problem of limited signal paths in the first leadframe.
[0027] In one embodiment, since the second leadframe includes additional signal transmission paths and heat dissipation paths, the number of pins on the first leadframe can be reduced, thereby reducing the area of the first leadframe.
[0028] Figure 2 This is a schematic diagram of a portion of a final conductor frame including the first conductor frame and the second conductor frame according to a first embodiment of the present disclosure. Figure 2 As shown, the first leadframe includes a stepped structure, wherein the die 110 is bonded to the upper layer of the stepped structure, and the second leadframe is bonded to the lower layer of the stepped structure.
[0029] Figure 3 This is a schematic diagram of a portion of a final conductor frame including the first conductor frame and the second conductor frame according to a second embodiment of the present disclosure. Figure 3 As shown, the first leadframe includes a stepped structure, and the second leadframe also includes a stepped structure (which may be referred to as a reverse stepped structure), wherein the upper layer of the stepped structure of the second leadframe is bonded to the lower layer of the stepped structure of the first leadframe, and the upper layer of the stepped structure of the first leadframe is bonded to the lower layer of the stepped structure of the second leadframe. Furthermore, the grain 110 is bonded to the second leadframe using an adhesive material.
[0030] Figure 4 This is a schematic diagram of a portion of a final conductor frame including the first conductor frame and the second conductor frame according to a third embodiment of the present disclosure. Figure 4 As shown, the first lead frame is bonded to the lower layer of the two stepped structures of the second lead frame, and the grains 110 are bonded to the second lead frame and the first lead frame by using an adhesive material.
[0031] In the above Figure 2 , Figure 3 and Figure 4 In the illustrated embodiment, the adhesive material used to bond the die, the first leadframe, and the second leadframe can be designed to be conductive or non-conductive based on the designer's considerations, so that the final leadframe has a suitable signal transmission path. Furthermore, by using the above embodiment, the final leadframe can have multi-directional heat dissipation paths, thereby providing good heat dissipation.
[0032] In one embodiment, at least one of the first leadframe and the second leadframe includes a locking hole (mold locking hole), wherein the locking hole is used to securely position the leadframe within the mold during molding or for subsequent die assembly processes. Figure 5 The first conductor frame is shown to be a multi-hole conductor frame containing keyholes.
[0033] Figure 6 This is a flowchart illustrating the manufacturing process of a final leadframe comprising a first leadframe and a second leadframe according to an embodiment of the present disclosure. In step 600, the process begins. In step 602, a metal sheet or strip made of copper, a copper alloy, an iron-nickel alloy, or other suitable material is used to manufacture the first leadframe via a top etching, surface treatment, and adhesive coating process. Specifically, the top etching process removes metal from the metal sheet or strip to form the desired leadframe pattern. Photochemical etching is commonly used for high-precision leadframes and typically includes the following steps: material cleaning, photoresist coating, exposure, development, etching, photoresist stripping, cleaning, and inspection. After etching and cleaning, the first leadframe undergoes various surface treatments to enhance its properties and ensure reliable performance in the semiconductor package 100. These treatments improve wire bonding, die adhesion, corrosion resistance, and adhesion to molding compound. Common surface treatments include the following steps: cleaning, electroplating, roughening, chemical conversion coating, self-assembled monolayers (SAMs), and passivation. It should be noted that the top etching process and surface treatment operations are known to those skilled in the art, and therefore further description is omitted here. Furthermore, the adhesive layer coating process is performed to apply an adhesive material (e.g., epoxy resin or other polymer) to the first leadframe for bonding the first leadframe to the die 110 and / or the second leadframe.
[0034] In step 604, a metal sheet or strip made of copper, copper alloy, iron-nickel alloy, or other suitable material is used to manufacture the second leadframe via bottom etching, surface treatment, and adhesive layer coating processes. Specifically, the bottom etching process removes metal from the metal sheet or strip to form the desired leadframe pattern. After etching and cleaning, the second leadframe undergoes various surface treatments to enhance its properties and ensure reliable performance in the semiconductor package 100. Furthermore, the adhesive layer coating process is performed to apply an adhesive material (such as epoxy resin or other polymers) to the second leadframe for bonding to the die 110 and / or the first leadframe.
[0035] In step 606, the first lead frame and the second lead frame are stacked and joined together using an adhesive material to manufacture the final lead frame.
[0036] After successfully manufacturing the final leadframe, the die 110 is then bonded to it. A series of steps are then performed to ensure the functionality and reliability of the semiconductor package 100, including wire bonding, molding, lead trimming and shaping, marking, testing, and final packaging. Since the post-die bonding processes in the semiconductor package described above are known to those skilled in the art, further description is omitted here.
[0037] The above description is only a preferred embodiment of the present invention. All equivalent changes and modifications made in accordance with the claims of the present invention should be included within the scope of the present invention.
Claims
1. A package comprising: One grain; and A first conductor frame and a second conductor frame, wherein the first conductor frame and the second conductor frame are stacked and bonded together by using an adhesive material to form a final conductor frame; The grain is bonded to the final lead frame.
2. The package of claim 1, wherein the first leadframe includes a stepped structure, the die is bonded to the upper layer of the stepped structure, and the second leadframe is bonded to the lower layer of the stepped structure.
3. The package as claimed in claim 1, wherein the first lead frame includes a first stepped structure, and the second lead frame includes a second stepped structure, the upper layer of the second stepped structure being coupled to the lower layer of the first stepped structure, and the upper layer of the first stepped structure being coupled to the lower layer of the second stepped structure.
4. The package of claim 3, wherein a portion of the die is bonded to the second lead frame.
5. The package of claim 1, wherein the second leadframe is bonded to the lower layer of two stepped structures of the first leadframe, and a portion of the die is bonded to the second leadframe and the first leadframe.
6. A conductor frame, comprising: A first conductor frame; and A second conductor frame, wherein the first conductor frame is stacked with the second conductor frame and joined together by using an adhesive material to form a final conductor frame.
7. The leadframe of claim 6, wherein the first leadframe includes a stepped structure, the upper layer of the stepped structure is used to bond a grain, and the second leadframe is bonded to the lower layer of the stepped structure.
8. The conductor frame as claimed in claim 6, wherein the first conductor frame includes a first stepped structure, and the second conductor frame includes a second stepped structure, the upper layer of the second stepped structure being joined to the lower layer of the first stepped structure, and the upper layer of the first stepped structure being joined to the lower layer of the second conductor frame.
9. The lead frame of claim 8, wherein a portion of the second lead frame is used to bond a grain.
10. The conductor frame of claim 6, wherein the second conductor frame is joined to the lower layer of the two stepped structures of the first conductor frame.
11. A method for manufacturing a conductor frame, comprising: Manufacture a first conductor frame; Manufacture a second conductor frame; and The first conductor frame and the second conductor frame are stacked and joined to form a final conductor frame that serves as the conductor frame.
12. The method of manufacturing a leadframe as claimed in claim 11, wherein the first leadframe includes a stepped structure, the upper layer of the stepped structure being used to bond a grain, and the second leadframe being bonded to the lower layer of the stepped structure.
13. The method of manufacturing a lead frame as claimed in claim 11, wherein the first lead frame includes a first stepped structure, and the second lead frame includes a second stepped structure, the upper layer of the second stepped structure being joined to the lower layer of the first stepped structure, and the upper layer of the first stepped structure being joined to the lower layer of the second lead frame.
14. The method of manufacturing a lead frame as claimed in claim 13, wherein a portion of the second lead frame is used to bond a grain.
15. The method of manufacturing a conductor frame as claimed in claim 11, wherein the second conductor frame is joined to the lower layer of two stepped structures of the first conductor frame.
16. The method of manufacturing a conductor frame as claimed in claim 11, wherein the steps of manufacturing the first conductor frame and manufacturing the second conductor frame comprise: The first lead frame is manufactured by performing a top etching, a surface treatment, and an adhesive coating process; and The second lead frame is manufactured by performing a bottom etching, the surface treatment, and the adhesive layer coating process.