Package structure and method of forming the same

Abstract

A packaging structure and a forming method thereof, the forming method comprises the following steps: providing a metal substrate; providing a bending pin, the bending pin comprises a front end part, a connecting part and a terminal part, the terminal part is above the front end part, and one end of the front end part and one end of the terminal part are connected through the connecting part; mounting the front end part of the bending pin on the upper surface of the edge area of the metal substrate; providing a first chip, the first chip comprises opposite back surfaces and a functional surface, the functional surface is provided with a first pad, and the back surface of the first chip is mounted on the upper surface of the middle area of the metal substrate; providing a second chip, the second chip is mounted on part of the functional surface of the first chip and part of the upper surface of the front end part, and the second chip is electrically connected with the first chip and the front end part; forming a first metal lead wire which is electrically connected with the front end part on the first chip; and forming a plastic sealing layer which covers the first chip, the second chip and the side of the metal substrate. The method avoids the problems of poor soldering workability and point breakage, and saves manufacturing cost.

Description

Technical Field

[0001] This application relates to the field of semiconductor packaging, and more particularly to a packaging structure and a method for forming the same. Background Technology

[0002] Currently, with the increasing demand for automotive products, the requirements for chip packaging are also becoming more stringent, and the packaging size is trending towards larger sizes.

[0003] Larger chip packages currently available typically use Quad Flat No-leads Package (QFN). In larger QFN packages, to avoid excessively long solder wires, an inward lead wire bonding design is required. If the inward leads are too long, the frame is prone to warping and deformation, and the solder wires may experience poor workability and breakage. While adding raised heating elements to support the inward leads can improve frame strength for soldering, this process is time-consuming and increases manufacturing costs. Summary of the Invention

[0004] Some embodiments of this application provide a method for forming an encapsulation structure, including:

[0005] A metal substrate is provided, the metal substrate including a central region and an edge region surrounding the central region;

[0006] A bent pin is provided, the bent pin including a front end, a connecting part and an end part, the end part being located above the front end, and one end of the front end and one end of the end part being connected through the connecting part;

[0007] The front ends of the plurality of bent pins are attached to the upper surface of the edge region of the metal substrate;

[0008] A first chip is provided, the first chip including opposing back side and functional side, the functional side having a first pad, and the back side of the first chip is attached to the upper surface of the middle region of the metal substrate.

[0009] A second chip is provided, which is mounted across a portion of the functional surface of the first chip and a portion of the upper surface of the front end, and the second chip is electrically connected to the first chip and the front end.

[0010] Forming a first metal lead that electrically connects the first pad on the first chip to the front end of the corresponding bent pin;

[0011] A molding compound is formed that covers the first chip, the second chip, the first metal lead, and the side of the metal substrate, the molding compound exposing the upper surface of the end portion and the lower surface of the metal substrate.

[0012] In some embodiments, the method further includes forming a solder layer on the upper surface of the end portion.

[0013] In some embodiments, the front end portion and the end portion each include a first end and a second end opposite to each other, the connecting portion includes an upper end and a lower end opposite to each other, the lower end of the connecting portion is connected to the second end of the front end portion, and the upper end of the connecting portion is connected to the first end or the second end of the end portion.

[0014] In some embodiments, the centerline of the connecting portion is perpendicular to or forms an angle with the upper surface of the front end portion.

[0015] In some embodiments, the back side of the first chip is attached to the upper surface of the middle region of the metal substrate by a first adhesive; the front end of the bent pin is attached to the upper surface of the edge region of the metal substrate by an insulating adhesive film.

[0016] In some embodiments, the second chip includes opposing functional surfaces and a back surface, the functional surface of the second chip having a second pad, and the back surface of the second chip being mounted across a portion of the functional surface of the first chip and a portion of the upper surface of the front end by a second adhesive.

[0017] In some embodiments, the method further includes: forming a second metal lead that electrically connects a second pad of the second chip to a corresponding first pad on the first chip and to the front end of a corresponding bent pin; the molding compound further covers the second metal lead.

[0018] In some embodiments, the second chip includes opposing functional surfaces and back surfaces, with raised solder bumps on the functional surfaces of the second chip to flip-chip onto a portion of the functional surfaces of the first chip and a portion of the upper surface of the front end, and the second chip is soldered to a corresponding first pad on the first chip and to the front end of the corresponding bent pin via the solder bumps.

[0019] In some embodiments, the total package thickness of the first chip and the second chip on the metal substrate is less than the height between the upper surface of the end portion of the bent pin and the upper surface of the metal substrate.

[0020] Some embodiments of this application also provide a packaging structure, including:

[0021] A metal substrate, the metal substrate including a central region and an edge region surrounding the central region;

[0022] A bent pin, the bent pin including a front end, a connecting part and an end part, the end part being located above the front end, one end of the front end and one end of the end part being connected through the connecting part, and the front ends of a plurality of bent pins being attached to the upper surface of the edge region of the metal substrate;

[0023] A first chip, the first chip having opposing back sides and functional sides, the functional sides having first pads, the back side of the first chip being attached to the upper surface of the middle region of the metal substrate;

[0024] The second chip is mounted across a portion of the functional surface of the first chip and a portion of the upper surface of the front end, and the second chip is electrically connected to the first chip and the front end.

[0025] A first metal lead electrically connecting the first pad on the first chip to the front end of the corresponding bent pin;

[0026] A molding compound covering the first chip, the second chip, the first metal lead, and the side of the metal substrate, wherein the molding compound exposes the upper surface of the end portion and the lower surface of the metal substrate.

[0027] In some embodiments, it further includes a solder layer located on the upper surface of the end portion.

[0028] In some embodiments, the front end portion and the end portion each include a first end and a second end opposite to each other, the connecting portion includes an upper end and a lower end opposite to each other, the lower end of the connecting portion is connected to the second end of the front end portion, and the upper end of the connecting portion is connected to the first end or the second end of the end portion.

[0029] In some embodiments, the centerline of the connecting portion is perpendicular to or forms an angle with the upper surface of the front end portion.

[0030] In some embodiments, the back side of the first chip is attached to the upper surface of the middle region of the metal substrate by a first adhesive; the front end of the bent pin is attached to the upper surface of the edge region of the metal substrate by an insulating adhesive film.

[0031] In some embodiments, the second chip includes opposing functional surfaces and a back surface, the functional surface of the second chip having a second pad, and the back surface of the second chip being mounted across a portion of the functional surface of the first chip and a portion of the upper surface of the front end by a second adhesive.

[0032] In some embodiments, the method further includes: a second metal lead electrically connecting the second pad of the second chip to a corresponding first pad on the first chip and to the front end of the corresponding bent pin; the molding compound further covers the second metal lead.

[0033] In some embodiments, the second chip includes opposing functional surfaces and back surfaces, with raised solder bumps on the functional surfaces of the second chip, the second chip being flip-chip mounted on a portion of the functional surfaces of the first chip and a portion of the upper surface of the front end, and the second chip being soldered to a corresponding first pad on the first chip and to the front end of a corresponding bent pin via the solder bumps.

[0034] In some embodiments, the total package thickness of the first chip and the second chip on the metal substrate is less than the height between the upper surface of the end portion of the bent pin and the upper surface of the metal substrate.

[0035] The packaging structure and its formation method in some of the foregoing embodiments of this application include the following steps: After providing a metal substrate, a bent pin is provided. The bent pin includes a front end, a connecting portion, and an end portion. The end portion is located above the front end, and one end of the front end and one end of the end portion are connected through the connecting portion. The front ends of a plurality of bent pins are attached to the upper surface of an edge region of the metal substrate. A first chip is provided, the first chip including a back side and a functional side, the functional side having a first pad. The back side of the first chip is attached to the upper surface of a middle region of the metal substrate. A second chip is provided, the second chip being attached across a portion of the functional side of the first chip and a portion of the upper surface of the front end, the second chip being electrically connected to the first chip and the front end. A first metal lead is formed to electrically connect the first pad on the first chip to the front end of the corresponding bent pin. A molding compound is formed covering the first chip, the second chip, the first metal lead, and the side surface of the metal substrate, the molding compound exposing the upper surface of the end portion and the lower surface of the metal substrate. The existing QFN package structure uses bent leads to replace the internal leads. The bent leads are attached to the upper surface of the edge area of ​​the metal substrate through an insulating adhesive film. The bottom of the bent leads 104 is effectively supported, making them less prone to warping or deformation. The front end of the bent leads does not need to be too long, thus avoiding problems such as poor wire bonding workability and breakage caused by lead deformation and excessive length. Furthermore, the front end of the bent leads can serve as a support boss for the second chip mounting, eliminating the need to add a separate boss for support. This can save manufacturing costs, improve work efficiency, and meet the packaging requirements of multiple chips. Attached Figure Description

[0036] Figures 1-8 This is a schematic diagram of the encapsulation structure formation process in some embodiments of this application. Detailed Implementation

[0037] The specific embodiments of this application will be described in detail below with reference to the accompanying drawings. In describing the embodiments of this application in detail, for ease of explanation, the schematic diagrams may be partially enlarged without adhering to the general scale, and the schematic diagrams are merely examples and should not limit the scope of protection of this application. Furthermore, in actual manufacturing, the three-dimensional spatial dimensions of length, width, and depth should be included.

[0038] This application first provides a method for forming a packaging structure, which will be described in detail below with reference to the accompanying drawings.

[0039] refer to Figure 1 A metal substrate 100 is provided, the metal substrate 100 including a central region and an edge region surrounding the central region.

[0040] The metal substrate 100 serves as a platform for subsequent processes. On one hand, the upper surface of the middle region of the metal substrate 100 is subsequently used to mount the first chip and the second chip, and the upper surface of the edge region of the metal substrate 100 is subsequently used to mount bent leads. On the other hand, the metal substrate 100 can also serve as a heat sink to dissipate heat from the subsequently mounted first chip.

[0041] In some embodiments, the metal substrate 100 may be a single-layer or multi-layer stacked structure. When the metal substrate 100 is a multi-layer stacked structure, in specific embodiments, the metal substrate 100 may be a two-layer stacked structure (e.g., including a bottom substrate and a top substrate located on the bottom substrate) or a three-layer stacked structure (e.g., including a bottom substrate, an intermediate substrate located on the bottom substrate, and a top substrate located on the intermediate substrate).

[0042] In some embodiments, the size of the upper portion of the metal substrate 100 is greater than or equal to the size of the lower portion of the metal substrate 100.

[0043] In some embodiments, the material of the metal substrate 100 is one or more of W, Al, Cu, Ti, Ag, Au, Pt, and Ni.

[0044] The metal substrate 100 includes an upper surface and a lower surface opposite to each other. In some embodiments, a protective film 101 is attached to the lower surface of the metal substrate 100. ， The protective film 101 serves two purposes: firstly, to support the metal substrate 100, and secondly, to prevent the lower surface of the metal substrate 100 from being contaminated by the material of the molding layer and from overflowing during the subsequent formation of the molding layer 113.

[0045] In some embodiments, the material of the protective film 101 may be one or more of high-temperature resistant polymers such as polyimide, polyetherketone, and polyetheretherketone.

[0046] In some embodiments, reference Figure 2 An insulating adhesive film 103 is formed on the upper surface of the edge region of the metal substrate 100.

[0047] The insulating adhesive film 103 has both adhesive and insulating properties. The insulating adhesive film 103 is subsequently used to attach bent leads to the upper surface of the edge region of the metal substrate 100 and to electrically isolate the bent leads from the metal substrate 100.

[0048] In one specific embodiment, the insulating adhesive film 103 is made of a resin that has both adhesive and insulating properties. The insulating adhesive film 103 can be formed using a lamination process or an adhesive dispensing process.

[0049] refer to Figure 3 A bent pin 104 is provided, the bent pin 104 includes a front end portion 105, a connecting portion 106 and an end portion 107, the end portion 107 is located above the front end portion 105, and one end of the front end portion 105 and one end of the end portion 107 are connected through the connecting portion 106; a plurality of the bent pins 104 are attached to the upper surface of the edge region of the metal substrate 100.

[0050] The front end 105 of the bent pin 104 serves as an inner pin for electrical connection to the first chip and the second chip, and the end 107 of the bent pin 104 serves as an outer pin for electrical connection between the package structure formed in this application and other devices, other package structures or package substrates.

[0051] The front end 105, connecting part 106, and end part 107 of the bent pin 104 are an integral structure. Figure 3 For ease of illustration, the front end portion 105, the connecting portion 106, and the end portion 107 are distinguished by dashed lines.

[0052] In some embodiments, the material of the bent pin 104 is a metal, specifically one or more of W, Al, Cu, Ti, Ag, Au, Pt, and Ni.

[0053] In some embodiments, the front portion 105 and the end portion 107 of the bent pin 104 each include a first end and a second end opposite to each other, and the connecting portion 106 includes an upper end and a lower end opposite to each other. The lower end of the connecting portion 106 is connected to the second end of the front portion 105, and the upper end of the connecting portion 106 is connected to either the first end or the second end of the end portion 107. In a specific embodiment, refer to... Figure 3The lower end of the connecting portion 106 is connected to the second end of the front portion 105, and the upper end of the connecting portion 106 is connected to the first end of the end portion 107, forming a "Z"-shaped or Z-like bent pin 104. This increases the packaging space between the pins of the bent pin 104, which is beneficial for multi-chip packaging. In another specific embodiment, the lower end of the connecting portion is connected to the second end of the front portion, and the upper end of the connecting portion is connected to the second end of the end portion, forming a "]"-shaped bent pin 104. This allows the packaging structure to occupy a smaller area, improving integration.

[0054] In some embodiments, the centerline of the connecting portion 106 is perpendicular to or forms an angle with the upper surface of the front end portion 105. In a specific embodiment, the angle α between the centerline of the connecting portion 106 and the upper surface of the front end portion 105 is 40°-80°.

[0055] In one specific embodiment, the front end 105 of the bent pin 104 is attached to the upper surface of the edge region of the metal substrate 100 via an insulating adhesive film 103.

[0056] In the formation of the packaging structure of this application, bent leads 104 are used to replace the inner leads in the existing QFN packaging structure. The bent leads 104 are attached to the upper surface of the edge area of ​​the metal substrate 100 through an insulating adhesive film 103. The bottom of the bent leads 104 is effectively supported and is not easy to warp or deform. Moreover, the front end 105 of the bent leads 104 does not need to be too long, thereby avoiding problems such as poor wire bonding workability and breakage caused by lead deformation and excessive length. Furthermore, the front end 105 of the bent leads 104 can serve as a support boss when mounting the second chip, so there is no need to add a separate boss for support, which can save manufacturing costs, improve work efficiency, and meet the packaging requirements of multiple chips.

[0057] refer to Figure 4 A first chip 107 is provided, the first chip 107 includes an opposing back side and a functional side, the functional side having a first pad, and the back side of the first chip 107 is attached to the upper surface of the middle region of the metal substrate 100.

[0058] The first chip 107 includes a back side and a functional side. The functional side has multiple first pads. An integrated circuit (not shown) with a specific function is formed in the first chip, and the first pads are electrically connected to the integrated circuit. In some embodiments, the material of the first pads is one or more of aluminum, nickel, tin, tungsten, platinum, copper, titanium, chromium, tantalum, gold, and silver. In some embodiments, the first chip 107 includes, but is not limited to, a signal processing chip, a logic control chip, a memory chip, a sensor chip, a power supply chip, or a radio frequency chip.

[0059] In some embodiments, the back side of the first chip 107 is attached to the upper surface of the middle region of the metal substrate 100 by a first adhesive 109.

[0060] Continue to refer to Figure 4 A second chip 108 is provided, which is mounted across a portion of the functional surface of the first chip 107 and a portion of the upper surface of the front end portion 105.

[0061] The second chip 108 includes a back side and a functional side, the functional side having multiple second pads. An integrated circuit (not shown) with a specific function is formed in the second chip 108, and the second pads are electrically connected to the integrated circuit. In some embodiments, the material of the second pads is one or more of aluminum, nickel, tin, tungsten, platinum, copper, titanium, chromium, tantalum, gold, and silver. In some embodiments, the second chip 108 includes, but is not limited to, a signal processing chip, a logic control chip, a memory chip, a sensor chip, a power supply chip, or a radio frequency chip.

[0062] In some embodiments, continue to refer to Figure 4 The back of the second chip 108 is attached across a portion of the functional surface of the first chip 107 and a portion of the upper surface of the front end portion 105 by a second adhesive (not shown in the figure).

[0063] In other embodiments, the second chip includes opposing functional surfaces and back surfaces, with raised solder bumps on the functional surfaces of the second chip to flip-chip onto a portion of the functional surfaces of the first chip 107 and a portion of the upper surface of the front end portion 105. The second chip is soldered to a corresponding first pad on the first chip 107 and to the front end portion 105 of the corresponding bent pin 104 via the solder bumps.

[0064] refer to Figure 5 This forms a first metal lead 111 that electrically connects the first pad on the first chip 107 to the front end 105 of the corresponding bent pin 104.

[0065] In some embodiments, the back side of the second chip 108 is mounted across a portion of the functional surface of the first chip 107 and a portion of the upper surface of the front end portion 105 by a second adhesive (not shown in the figure), and further includes: forming a second metal lead 112 that electrically connects the second pad of the second chip 108 to a corresponding first pad on the first chip 107 and to the front end portion 105 of the corresponding bent pin 104, so as to electrically connect the second chip 108 to the first chip 107 and the front end portion 105.

[0066] In some embodiments, the number of first metal leads 111 is at least one, electrically connecting the first pad on the first chip 107 to the front end 105 of the corresponding bent pin 104. The number of second metal leads 112 is at least two, electrically connecting the second pad of the second chip 108 to the corresponding first pad on the first chip 107 via different second metal leads 112, and electrically connecting the second pad of the second chip 108 to the front end 105 of the corresponding bent pin 104.

[0067] The first metal lead 111 and the second metal lead 112 can be made of one or more of gold, aluminum, copper, silver, nickel, and palladium, and the forming process includes wire bonding.

[0068] In some embodiments, the total package thickness of the first chip 107 and the second chip 112 on the metal substrate 100 (the vertical distance from the surface of the highest point of the second metal lead 112 to the upper surface of the metal substrate 100) is less than the height between the upper surface of the end portion 107 of the bent lead 104 and the upper surface of the metal substrate 100, so as to facilitate the mounting of multiple chips.

[0069] refer to Figure 6 A molding compound 113 is formed to cover the first chip 107, the second chip 108, the first metal lead 111, and the side of the metal substrate 100. The molding compound 113 exposes the upper surface of the end portion 107 and the lower surface of the metal substrate 100.

[0070] In some embodiments, a film 110 is formed on the upper surface of the end portion 107 of the bent pin 104 before the molding layer 113 is formed. ， The membrane 110 can prevent the upper surface of the end portion 107 of the pin 104 from being covered with the molding compound material during the formation of the molding compound 113.

[0071] In some embodiments, the material of the membrane 110 may be one or more of high-temperature resistant polymers such as polyimide, polyetherketone, and polyetheretherketone.

[0072] In some embodiments, the material of the molding compound 113 may be a filler-containing epoxy resin, polyimide resin, benzocyclobutene resin, or polybenzoxazole resin; or it may be a filler-containing polybutylene terephthalate, polycarbonate, polyethylene terephthalate, polyethylene, polypropylene, polyolefin, polyurethane, polyolefin, polyethersulfone, polyamide, polyimide, ethylene-vinyl acetate copolymer, or polyvinyl alcohol. The filler may be an inorganic filler or an organic filler. The process for forming the molding compound 113 includes injection molding or transfer molding.

[0073] In some embodiments, when the second metal lead 112 is formed, the molding layer 113 also covers the second metal lead 112.

[0074] In some embodiments, reference Figure 7 Remove the membrane 110 (reference) Figure 6 ).

[0075] refer to Figure 8 It also includes forming a solder layer 114 on the upper surface of the end portion 107 of the bent pin 104.

[0076] The solder layer 114 can be made of one or more of the following materials: tin, tin-silver, tin-lead, silver-copper, tin-silver-copper, tin-silver-zinc, tin-zinc, tin-bismuth-indium, tin-indium, tin-gold, tin-copper, tin-zinc-indium, or tin-silver-antimony. The process for forming the solder layer 114 includes stencil printing or electroplating.

[0077] It also includes removing the protective film 101 after the solder layer 114 is formed.

[0078] Some embodiments of this application also provide a packaging structure, see reference. Figure 8 ,include:

[0079] A metal substrate 100, the metal substrate 100 including a central region and an edge region surrounding the central region;

[0080] A bent pin 104 includes a front end portion 105, a connecting portion 106, and an end portion 107. The end portion 107 is located above the front end portion 105. One end of the front end portion 105 and one end of the end portion 107 are connected through the connecting portion 106. The front ends 105 of a plurality of bent pins 104 are attached to the upper surface of the edge region of the metal substrate 100.

[0081] A first chip 107 includes a back side and a functional side, the functional side having a first pad, and the back side of the first chip 107 is attached to the upper surface of the middle region of the metal substrate 100.

[0082] The second chip 108 is mounted across a portion of the functional surface of the first chip and a portion of the upper surface of the front end, and the second chip is electrically connected to the first chip and the front end.

[0083] A first metal lead 111 electrically connects the first pad on the first chip 107 to the front end 105 of the corresponding bent pin 104;

[0084] A molding compound 113 is formed covering the first chip 107, the second chip 108, the first metal lead 111, and the side of the metal substrate 100. The molding compound 113 exposes the upper surface of the end portion 107 and the lower surface of the metal substrate 100.

[0085] In some embodiments, it further includes a solder layer 114 located on the upper surface of the end portion 107.

[0086] In some embodiments, the front end portion 105 and the end portion 107 each include a first end and a second end opposite to each other, the connecting portion 106 includes an upper end and a lower end opposite to each other, the lower end of the connecting portion 106 is connected to the second end of the front end portion 105, and the upper end of the connecting portion 106 is connected to the first end or the second end of the end portion 107.

[0087] In some embodiments, the centerline of the connecting portion 106 is perpendicular to or forms an angle with the upper surface of the front end portion 105.

[0088] In some embodiments, the back side of the first chip 107 is attached to the upper surface of the middle region of the metal substrate 100 by a first adhesive 109; the front end 105 of the bent pin 104 is attached to the upper surface of the edge region of the metal substrate 100 by an insulating adhesive film 103.

[0089] In some embodiments, the second chip 108 includes opposing functional surfaces and a back surface. The functional surface of the second chip 108 has a second pad, and the back surface of the second chip 108 is mounted across a portion of the functional surface of the first chip 107 and a portion of the upper surface of the front end portion 105 by a second adhesive. In some embodiments, the device further includes: a second metal lead 112 electrically connecting the second pad of the second chip 108 to a corresponding first pad on the first chip 107 and to the front end portion 105 of the corresponding bent pin 104, the molding compound 113 further covering the second metal lead 112.

[0090] In some embodiments, the second chip includes opposing functional surfaces and back surfaces, with raised solder bumps on the functional surfaces of the second chip, and the second chip is flip-chip mounted on a portion of the functional surfaces of the first chip 107 and a portion of the upper surface of the front end portion 105. The second chip is soldered to a corresponding first pad on the first chip 107 and to the front end portion 105 of the corresponding bent pin 104 via the solder bumps.

[0091] In some embodiments, the total package thickness of the first chip 107 and the second chip 108 on the metal substrate 100 is less than the height between the upper surface of the end portion 107 of the bent pin 104 and the upper surface of the metal substrate 100.

[0092] It should be noted that the terms "comprising" and "having," and their variations, used in this application are intended to cover non-exclusive inclusion. The terms "first," "second," etc., are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence, unless explicitly indicated by the context. It should be understood that such data can be used interchangeably where appropriate. Furthermore, the embodiments and features described in the embodiments of this application can be combined with each other unless otherwise specified. In addition, descriptions of well-known components and technologies have been omitted in the above description to avoid unnecessarily obscuring the concepts of this application. In the various embodiments described above, each embodiment focuses on its differences from other embodiments; similar or identical parts between embodiments can be referred to (or understood) interchangeably.

[0093] Although this application has been disclosed above with reference to preferred embodiments, it is not intended to limit this application. Any person skilled in the art can make possible changes and modifications to the technical solutions of this application by utilizing the methods and techniques disclosed above without departing from the spirit and scope of this application. Therefore, any simple modifications, equivalent changes and alterations made to the above embodiments based on the technical essence of this application without departing from the content of the technical solutions of this application shall fall within the protection scope of the technical solutions of this application.

Claims

1. A method for forming an encapsulation structure, characterized in that, include: A metal substrate is provided, the metal substrate including a central region and an edge region surrounding the central region; A bent pin is provided, the bent pin including a front end, a connecting part and an end part, the end part being located above the front end, and one end of the front end and one end of the end part being connected through the connecting part; The front ends of the plurality of bent pins are attached to the upper surface of the edge region of the metal substrate; a first chip is provided, the first chip including opposing back sides and functional sides, the functional sides having first pads, and the back side of the first chip is attached to the upper surface of the middle region of the metal substrate. A second chip is provided, which is mounted across a portion of the functional surface of the first chip and a portion of the upper surface of the front end, and the second chip is electrically connected to the first chip and the front end. Forming a first metal lead that electrically connects the first pad on the first chip to the front end of the corresponding bent pin; A molding compound is formed that covers the first chip, the second chip, the first metal lead, and the side of the metal substrate, the molding compound exposing the upper surface of the end portion and the lower surface of the metal substrate.

2. The method for forming the packaging structure according to claim 1, characterized in that, Also includes: A solder layer is formed on the upper surface of the end portion.

3. The method for forming the packaging structure according to claim 1, characterized in that, Both the front end and the end end include a first end and a second end, and the connecting part includes an upper end and a lower end. The lower end of the connecting part is connected to the second end of the front end, and the upper end of the connecting part is connected to the first end or the second end of the end end.

4. The method for forming the packaging structure according to claim 3, characterized in that, The centerline of the connecting part is perpendicular to or forms an angle with the upper surface of the front end.

5. The method for forming the packaging structure according to claim 1, characterized in that, The back of the first chip is attached to the upper surface of the middle region of the metal substrate by a first adhesive; the front end of the bent pin is attached to the upper surface of the edge region of the metal substrate by an insulating adhesive film.

6. The method for forming the packaging structure according to claim 1 or 5, characterized in that, The second chip includes a functional side and a back side, the functional side of the second chip has a second pad, and the back side of the second chip is attached across a portion of the functional side of the first chip and a portion of the upper surface of the front end by a second adhesive.

7. The method for forming the packaging structure according to claim 6, characterized in that, Also includes: A second metal lead is formed that electrically connects the second pad of the second chip to the corresponding first pad on the first chip and to the front end of the corresponding bent pin; the molding compound also covers the second metal lead.

8. The method for forming the packaging structure according to claim 1 or 5, characterized in that, The second chip includes a functional side and a back side. The functional side of the second chip has raised solder bumps. The second chip is flip-chip mounted on a portion of the functional side and a portion of the upper surface of the front end of the first chip. The second chip is soldered to a corresponding first pad on the first chip and to the front end of the corresponding bent pin via the solder bumps.

9. The method for forming the packaging structure according to claim 1, characterized in that, The total package thickness of the first chip and the second chip on the metal substrate is less than the height between the upper surface of the end portion of the bent pin and the upper surface of the metal substrate.

10. A packaging structure, characterized in that, include: A metal substrate, the metal substrate including a central region and an edge region surrounding the central region; a bent pin, the bent pin including a front end, a connecting part and an end part, the end part being located above the front end, one end of the front end and one end of the end part being connected through the connecting part, and the front ends of a plurality of bent pins being attached to the upper surface of the edge region of the metal substrate. A first chip, the first chip having opposing back sides and functional sides, the functional sides having first pads, the back side of the first chip being attached to the upper surface of the middle region of the metal substrate; A second chip, which is mounted across a portion of the functional surface of the first chip and a portion of the upper surface of the front end, is electrically connected to the first chip and the front end; a first metal lead electrically connects a first pad on the first chip to the front end of the corresponding bent pin. A molding compound covering the first chip, the second chip, the first metal lead, and the side of the metal substrate, wherein the molding compound exposes the upper surface of the end portion and the lower surface of the metal substrate.

11. The packaging structure according to claim 10, characterized in that, Also includes: Solder layer located on the upper surface of the end portion.

12. The packaging structure according to claim 10, characterized in that, Both the front end and the end end include a first end and a second end, and the connecting part includes an upper end and a lower end. The lower end of the connecting part is connected to the second end of the front end, and the upper end of the connecting part is connected to the first end or the second end of the end end.

13. The packaging structure according to claim 12, characterized in that, The centerline of the connecting part is perpendicular to or forms an angle with the upper surface of the front end.

14. The packaging structure according to claim 10, characterized in that, The back of the first chip is attached to the upper surface of the middle region of the metal substrate by a first adhesive; the front end of the bent pin is attached to the upper surface of the edge region of the metal substrate by an insulating adhesive film.

15. The packaging structure according to claim 10 or 14, characterized in that, The second chip includes a functional side and a back side, the functional side of the second chip has a second pad, and the back side of the second chip is attached across a portion of the functional side of the first chip and a portion of the upper surface of the front end by a second adhesive.

16. The packaging structure according to claim 15, characterized in that, Also includes: The second pad of the second chip is electrically connected to the corresponding first pad on the first chip and to the front end of the corresponding bent pin by a second metal lead. The molding layer also covers the second metal lead.

17. The packaging structure according to claim 10 or 14, characterized in that, The second chip includes a functional side and a back side, with raised solder bumps on the functional side of the second chip. The second chip is flip-chip mounted on a portion of the functional side and a portion of the upper surface of the front end of the first chip. The second chip is soldered to a corresponding first pad on the first chip and to the front end of the corresponding bent pin via the solder bumps.

18. The packaging structure according to claim 10, characterized in that, The total package thickness of the first chip and the second chip on the metal substrate is less than the height between the upper surface of the end portion of the bent pin and the upper surface of the metal substrate.

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