Packaging structure and manufacturing method thereof, and electronic device using the packaging structure

Abstract

The present invention provides a packaging structure and a manufacturing method thereof, and an electronic device using the packaging structure. The manufacturing method of the present invention first covers the bottom surface of the initial pin with a pre-coated metal layer, and then half-cuts the initial pin to form a pin with a stepped cutting groove, so that the base material of the pin is exposed at the stepped cutting groove of the pin; then, the surface of the stepped cutting groove is selectively covered with an organic solderability protective layer to prevent the surface of the stepped cutting groove of the pin from being oxidized. Then, when the packaging structure is welded to other devices, the solder can be welded at the stepped cutting groove, so as to perform 100% optical inspection from the side of the packaging structure to verify the integrity of the solder joint connection and achieve the purpose of verifying the electrical connection. The manufacturing method of the present invention only uses the selective covering of the organic solderability protective layer to achieve protection of the stepped cutting groove surface of the pin, without the need for performing an electroplating process, greatly reducing manufacturing costs, and will not cause environmental pollution.

Description

Technical Field

[0001] The present invention relates to the field of semiconductor packaging, and in particular to a packaging structure and a manufacturing method thereof, and an electronic device using the packaging structure. Background Art

[0002] For leadless packages, such as QFN (Quad Flat No-leads) components, it is common to have difficulty applying tin to the sides or insufficient tin climbing height after SMT patch processing and soldering, which affects the automated visual inspection (AVI) of the package structure.

[0003] The reason why it is difficult to tin the side of the package structure or the tin climbing height is insufficient is that the soldering ends of the pins on the side of the package structure are all bare copper, and copper is easily oxidized in the air to form copper oxide, which is difficult to tin or has insufficient tin climbing height. To solve this problem, the following measures can be taken: before the package cutting process is cut, a step cutting and electroplating process is added to the pins to cut to about half the thickness of the copper wire. After cleaning, 100% tin is plated on the solder pads at the bottom of the package and the copper surface exposed in the step cutting groove. The plating layer can protect the exposed copper and allow soldering in the step cutting groove area, so that 100% optical inspection can be carried out from the side of the package structure to verify the integrity of the solder joint connection, achieve the purpose of verifying the electrical connection, and ensure that the pins / terminals can be successfully soldered to the printed circuit board (PCB).

[0004] The process of 100% tin plating on the copper surface exposed in the solder pads and step-cut grooves on the bottom of the package is an electroplating process. This process consumes a lot of resources, produces wastewater, has a poor process environment, and wastewater treatment is time-consuming and expensive, and causes environmental pollution.

[0005] Therefore, how to ensure that the side tin creep height of the packaging structure meets the requirements, reduce costs, and avoid causing environmental pollution has become one of the problems that need to be solved urgently. Summary of the Invention

[0006] The technical problem to be solved by the present invention is to provide a packaging structure and a manufacturing method thereof, and an electronic device using the packaging structure, which can ensure that the tin creep height on the side of the packaging structure meets the requirements, reduce costs, and will not cause environmental pollution.

[0007] In order to solve the above problems, the present invention provides a manufacturing method of a packaging structure, which includes: providing a plastic packaging structure, the plastic packaging structure including an initial plastic packaging body, a chip and a lead frame, the chip and the lead frame are covered by the initial plastic packaging body, the lead frame includes an initial pin, the chip is electrically connected to the initial pin, the bottom surface of the initial pin is covered with a pre-coated metal layer, the pre-coated metal layer is exposed on the bottom surface of the initial plastic packaging body, and the material of the pre-coated metal layer is different from the material of the lead frame, the plastic packaging structure is divided into a plurality of plastic packaging units; the plastic packaging structure is half-cut along a first cutting line between adjacent plastic packaging units from the bottom surface of the plastic packaging structure to form a pin with a stepped cutting groove on the side; covering with an organic solderability protective layer, the organic solderability protective layer selectively covering the surface of the stepped cutting groove of the pin; cutting along a second cutting line between adjacent plastic packaging units to form a plurality of independent packaging structures, wherein the second cutting line is covered by the first cutting line, and the width of the second cutting line is smaller than the width of the first cutting line.

[0008] In one embodiment, the lead frame is a pre-plated lead frame, and the pre-coated metal layer is pre-formed on the bottom surface of the lead frame.

[0009] In one embodiment, the depth of half-cutting the plastic package structure along the first cutting line between adjacent plastic package units is half the thickness of the initial pins.

[0010] In one embodiment, the step of half-cutting the plastic package structure along the first cutting line between adjacent plastic package units to form a lead with a stepped cutting groove on the side further includes: the initial plastic package body is also cut to form a plastic package body with a stepped cutting groove on the side.

[0011] In one embodiment, the lead frame further includes frame connecting ribs located between adjacent plastic encapsulation units. In the step of half-cutting the plastic encapsulation structure along the first cutting path between adjacent plastic encapsulation units, the frame connecting ribs are also half-cut; in the step of covering the organic solderability protective layer, the organic solderability protective layer is also selectively covered on the cut surface of the frame connecting ribs.

[0012] In one embodiment, the width of the first cutting street is greater than the width of the frame connecting rib, and the width of the second cutting street is greater than or equal to the width of the frame connecting rib.

[0013] In one embodiment, the lead frame is made of copper, the pre-coated metal layer includes a nickel-palladium-gold composite layer, and the organic solderability protection layer includes a nitrogen-containing organic compound.

[0014] An embodiment of the present invention also provides a packaging structure, which includes: a plastic package body; a lead frame, which is covered by the plastic package body, and the lead frame includes a pin, the bottom surface of the pin is exposed to the bottom surface of the plastic package body, the side surface of the pin is exposed to the side surface of the plastic package body, and the side surface of the pin has a step cutting groove; a chip, which is covered by the plastic package body, and the chip is electrically connected to the pin; a pre-coated metal layer, which covers the bottom surface of the pin, and the material of the pre-coated metal layer is different from that of the lead frame; an organic solderability protective layer, which covers the surface of the step cutting groove of the pin from the connection between the side surface of the pin and the bottom surface of the pin.

[0015] In one embodiment, a side surface of the plastic package body has a stepped cutting groove, and the stepped cutting groove of the lead is located on an extension path of the stepped cutting groove of the plastic package body.

[0016] In one embodiment, the lead frame further includes a base island, the pins are distributed around the base island, the back of the chip is mounted on the base island, the front of the chip is electrically connected to the pins via bonding wires, and the pre-coated metal layer also covers the bottom surface of the base island of the lead frame.

[0017] An embodiment of the present invention provides an electronic device, which includes a substrate and a packaging structure arranged on the substrate. The packaging structure adopts the above-mentioned packaging structure, and is electrically connected to the substrate through a solder layer. The solder layer covers the pre-coated metal layer on the bottom surface of the pin of the packaging structure and fills the stepped cutting groove on the side of the pin. The organic solderability protective layer on the surface of the stepped cutting groove of the pin can be melted during welding, so that the solder layer can be directly welded to the pin substrate.

[0018] The manufacturing method of the package structure provided by the embodiment of the present invention first covers the bottom surface of the initial pin with a pre-coated metal layer, then half-cuts the initial pin to form a pin with a stepped cutting groove, so that the base material (e.g., copper) of the pin is exposed at the stepped cutting groove of the pin; and then covers it with an organic solderability protective layer, wherein the organic solderability protective layer can selectively cover the surface of the stepped cutting groove. The organic solderability protective layer can prevent the surface of the stepped cutting groove of the pin from being oxidized. When the package structure manufactured by the manufacturing method of the present invention is soldered to other devices (e.g., PCB boards), solder can be welded at the stepped cutting groove, so that 100% optical inspection can be performed from the side of the package structure to verify the integrity of the solder joint connection, thereby achieving the purpose of verifying the electrical connection and ensuring that the pin can be successfully soldered to other devices, such as printed circuit boards (PCBs). The manufacturing method of the present invention only uses the selective covering of the organic solderability protective layer to achieve protection of the stepped cutting groove surface of the pin, without the need for 100% tin plating at the stepped cutting groove of the pin to achieve the purpose of protection, and without the need for performing an electroplating process, which greatly reduces manufacturing costs and does not cause environmental pollution. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] To more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly describes the drawings required for describing the embodiments. Obviously, the drawings described below are only some embodiments of the present invention, and those skilled in the art can derive other drawings based on these drawings without inventive effort.

[0020] Figure 1 1 is a schematic diagram of the steps of a method for manufacturing a packaging structure provided by an embodiment of the present invention;

[0021] Figure 2A It is a bottom schematic diagram of a plastic package structure in the process flow of a method for manufacturing a package structure provided by an embodiment of the present invention;

[0022] Figure 2B It is along Figure 2A Cross-section of line A-A1;

[0023] Figure 2C This is a bottom schematic diagram of the plastic package structure after half-cutting the plastic package structure along the first cutting line between adjacent plastic package units in the process flow of the manufacturing method of the packaging structure provided by one embodiment of the present invention;

[0024] Figure 2D It is along Figure 2C Cross-section of line A-A1;

[0025] Figure 2E This is a schematic diagram of the bottom surface after being covered with an organic solderability protective layer in the process flow of the manufacturing method of the packaging structure provided by one embodiment of the present invention;

[0026] Figure 2F It is along Figure 2E Cross-section of line A-A1;

[0027] Figure 2G It is a bottom schematic diagram after cutting along the second cutting line between adjacent plastic encapsulation units in the process flow of the manufacturing method of the packaging structure provided by one embodiment of the present invention;

[0028] Figure 2H It is along Figure 2G Cross-section of line A-A1;

[0029] Figure 3 is a schematic diagram of an electronic device provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0030] The packaging structure and manufacturing method thereof, as well as specific embodiments of electronic devices using the packaging structure provided by the present invention are described in detail below with reference to the accompanying drawings.

[0031] Figure 1 This is a schematic diagram of the steps of a method for manufacturing a packaging structure according to an embodiment of the present invention. Figure 1 The manufacturing method of the packaging structure includes: step S10, providing a plastic packaging structure, the plastic packaging structure including an initial plastic packaging body, a chip and a lead frame, the chip and the lead frame are covered by the initial plastic packaging body, the lead frame includes an initial pin, the chip is electrically connected to the initial pin, the bottom surface of the initial pin is covered with a pre-coated metal layer, the pre-coated metal layer is exposed to the bottom surface of the initial plastic packaging body, and the material of the pre-coated metal layer is different from the material of the lead frame, and the plastic packaging structure is divided into a plurality of plastic packaging units; step S11, half-cutting the plastic packaging structure along a first cutting line between adjacent plastic packaging units from the bottom surface of the plastic packaging structure to form a pin with a stepped cutting groove on the side; step S12, covering with an organic solderability protective layer, the organic solderability protective layer selectively covering the stepped cutting groove surface of the pin; step S13, cutting along a second cutting line between adjacent plastic packaging units to form a plurality of independent packaging structures, wherein the second cutting line is covered by the first cutting line, and the width of the second cutting line is smaller than the width of the first cutting line.

[0032] The manufacturing method of the package structure provided by the embodiment of the present invention first covers the bottom surface of the initial pin with a pre-coated metal layer, then half-cuts the initial pin to form a pin with a stepped cutting groove, so that the base material (e.g., copper) of the pin is exposed at the stepped cutting groove of the pin; and then covers it with an organic solderability protective layer, wherein the organic solderability protective layer can selectively cover the surface of the stepped cutting groove. The organic solderability protective layer can prevent the surface of the stepped cutting groove of the pin from being oxidized. When the package structure manufactured by the manufacturing method of the present invention is soldered to other devices (e.g., PCB boards), solder can be welded at the stepped cutting groove, so that 100% optical inspection can be performed from the side of the package structure to verify the integrity of the solder joint connection, thereby achieving the purpose of verifying the electrical connection and ensuring that the pin can be successfully soldered to other devices, such as printed circuit boards (PCBs). The manufacturing method of the present invention only uses the selective covering of the organic solderability protective layer to achieve protection of the stepped cutting groove surface of the pin, without the need for 100% tin plating at the stepped cutting groove of the pin to achieve the purpose of protection, and without the need for performing an electroplating process, which greatly reduces manufacturing costs and does not cause environmental pollution.

[0033] Figures 2A to 2H It is a process flow chart of a method for manufacturing a packaging structure provided by one embodiment of the present invention.

[0034] See also Figure 1 、 Figure 2A and Figure 2B ,in, Figure 2A It is a schematic diagram of the bottom surface of the plastic package structure. Figure 2B It is along Figure 2A In the cross-sectional view along the A-A1 line, step S10 provides a plastic packaging structure, which includes an initial plastic packaging body 210, a chip (not shown in the drawings) and a lead frame. The chip and the lead frame are covered by the initial plastic packaging body 210. The lead frame includes an initial pin 220. The chip is electrically connected to the initial pin 220. The bottom surface of the initial pin 220 is covered with a pre-coated metal layer 230. The pre-coated metal layer 230 is exposed to the bottom surface of the initial plastic packaging body 210, and the material of the pre-coated metal layer 230 is different from that of the lead frame. The plastic packaging structure is divided into a plurality of plastic packaging units 200. The boundaries of the plastic packaging units 200 are shown by dotted lines in the figure.

[0035] The lead frame is a thin metal frame. In this embodiment, the lead frame is a copper-based lead frame. During the manufacturing process, after the copper-based lead frame is cut, its cut surface exposes the copper substrate. Copper is easily oxidized in the air, making the cut surface difficult to be wetted by solder, which cannot meet the requirements.

[0036] The lead frame includes multiple frame units (not shown in the drawings), each of which is encapsulated by the initial plastic encapsulation body 210 to form the encapsulation unit 200. Adjacent frame units are connected by frame connecting ribs 222, meaning the lead frame includes frame connecting ribs 222 located between adjacent encapsulation units 200. In this embodiment, the initial plastic encapsulation body 210 encapsulates not only the frame units but also the frame connecting ribs 222.

[0037] Each of the plastic packaging units 200 has the initial pins 220. In the packaging structure manufactured by the manufacturing method of the present invention, some pins of the packaging structure (such as Figure 2D The bottom and side surfaces of the pin 250 shown in FIG. 2 are not covered by the plastic package 270 (see FIG. Figure 2D ) is covered, and the initial pins 220 correspond to the pins of the packaging structure. Specifically, in the plastic packaging structure, the initial pins 220 can extend from the internal area of ​​the plastic packaging unit 200 to the side of the plastic packaging unit 200, and be connected to the frame connecting rib 222 on the side of the plastic packaging unit 200. The pre-coated metal layer 230 covers the bottom surface of the initial pins 220 of the lead frame. In some embodiments, the pre-coated metal layer 230 covers the entire bottom surface of the lead frame that is not covered by the initial plastic packaging body 210, for example, the pre-coated metal layer 230 covers the initial pins 220 and the bottom surface of the frame connecting rib 222. In some embodiments, the lead frame is a pre-plating lead frame (Pre-Plating frame Finish, PPF for short), that is, before the lead frame is plastic-coated with a plastic packaging material, the pre-coated metal layer 230 is pre-formed on the bottom surface of the lead frame. In some embodiments, the pre-coated metal layer 230 can be formed by chemical plating or electroplating process. In some embodiments, the lead frame further includes a base island 221 , the initial pins 220 are distributed around the base island 221 , and the pre-coated metal layer 230 further covers the bottom surface of the base island 221 of the lead frame.

[0038] The material of the pre-coated metal layer 230 is different from that of the lead frame. For example, in this embodiment, the lead frame is made of copper, and the material of the pre-coated metal layer 230 is a non-copper metal material. The pre-coated metal layer 230 can be a single metal layer or a multi-layer composite layer. For example, in one embodiment, the pre-coated metal layer 230 includes a nickel-palladium-gold composite layer (NI / Pd / Au).

[0039] See also Figure 1 、 Figure 2C and Figure 2D ,in, Figure 2Cis a bottom schematic diagram of the plastic packaging structure after half-cutting along the first cutting line 240 between adjacent plastic packaging units 200. Figure 2D It is along Figure 2C In the cross-sectional view along the A-A1 line, step S11, the plastic encapsulation structure is half-cut along the first cutting path 240 between adjacent plastic encapsulation units 200 from the bottom surface of the plastic encapsulation structure to form a pin 250 with a stepped cutting groove 251 on the side. In this step, in this embodiment, the plastic encapsulation structure is cut along the first cutting path 240 from the bottom surface of the plastic encapsulation structure, and the bottom surface of the plastic encapsulation structure is cut to form a groove, wherein the groove passing through the initial pin 220 of each plastic encapsulation unit 200 serves as the stepped cutting groove 251 of the pin 250, and the groove passing through the initial plastic encapsulation body 210 of each plastic encapsulation unit 200 serves as the stepped cutting groove 271 of the plastic encapsulation body 270. In this step, the pre-coated metal layer 230 located in the first cutting path 240 and covering the surface of the initial pin 220 is also cut. Figure 2C The dashed line is used to illustrate the boundary of the first cutting street 240 .

[0040] Half-cutting refers to partially cutting the molded structure, with the cutting depth being less than the thickness of the initial lead 220, to form a lead 250 with a stepped cut groove 251 on its side. In some embodiments, the depth of the half-cut along the first cut line 240 between adjacent molded units 200 is half the thickness of the initial lead 220. In this step, the molded structure is not completely separated in a direction perpendicular to the surface of the molded structure. The cut surface only exposes a portion of the side surface of the lead 250, forming the stepped cut groove 251 of the lead 250. The surface of the stepped cut groove 251 of the lead 250 exposes the base material of the lead frame. For example, in this embodiment, the surface of the stepped cut groove 251 of the lead 250 exposes the copper base material of the lead frame.

[0041] In some embodiments, when the molded structure is half-cut along the first cutting line 240 between adjacent molded units 200, the initial molded body 210 is also cut, forming a stepped cutting groove 271 on the side of the molded body 270. In some embodiments, when the molded structure is half-cut along the first cutting line 240 between adjacent molded units 200, the initial molded body 210 and the initial leads 220 are cut simultaneously, and the stepped cutting groove 251 of the lead 250 is located on the extension path of the stepped cutting groove 271 of the molded body 270.

[0042] In some embodiments, when the plastic encapsulation structure is half-cut along the first cutting line 240 between adjacent plastic encapsulation units 200, the frame connecting ribs 222 are located in the first cutting line 240, and the frame connecting ribs 222 are also half-cut, and the base island 221 is not located in the first cutting line 240, and the base island 221 is not cut.

[0043] The width W1 of the first cutting line 240 is greater than the width W2 of the frame connecting rib 222. When half cutting is performed, the bottom edge of the plastic package unit 200 can be half cut to form the step cutting groove 251 of the pin 250 and the step cutting groove 271 of the plastic package body 270. The width W2 of the frame connecting rib 222 is greater than the width W2 of the second cutting line 241 (marked at Figure 2E ) has the same width W3. In the subsequent step of cutting along the second cutting street 241, the plastic encapsulation unit 200 is separated to form a plurality of independent packaging structures.

[0044] See also Figure 1 、 Figure 2E and Figure 2F ,in, Figure 2E It is a schematic diagram of the bottom surface after being covered with the organic solderability protective layer 280. Figure 2F It is along Figure 2G In the cross-sectional view along line A-A1, step S12 is covering the organic solderability protective layer 280 . The organic solderability protective layer 280 selectively covers the surface of the step cutting groove 251 of the lead 250 .

[0045] The organic solderability preservative (OSP) 280 is a selective organic coating that can cover only a specific metal surface. For example, in this embodiment, the surface of the step-cut groove 251 of the lead 250 is a copper surface. Therefore, the material of the organic solderability preservative 280 is selected to cover only the surface of the step-cut groove 251 of the lead 250 and not the surface of the pre-coated metal layer 230. In some embodiments, the organic solderability preservative 280 includes a nitrogen-containing organic compound, such as a benzotriazole or an imidazole organic crystalline base. In other embodiments, if the surface of the step-cut groove 251 of the lead 250 is another metal surface, an organic coating that selectively covers that metal can be used as the organic solderability preservative 280.

[0046] Furthermore, in this embodiment, the cut surface of the frame connecting rib 222 is a copper surface, and the organic solderability protective layer 280 is also selectively covered on the cut surface of the frame connecting rib 222 .

[0047] In the embodiment provided by the present invention, the organic solderability protective layer 280 covers the surface of the step-cut groove 251 of the lead 250, thereby preventing the surface of the step-cut groove 251 of the lead 250 from being oxidized. During the reflow process of assembling the package structure to other devices (such as a printed circuit board), the organic solderability protective layer 280 easily melts into the solder, exposing the highly active copper surface, allowing the solder to bond to the surface of the step-cut groove 251. Furthermore, compared to forming an electroplated layer on the surface of the step-cut groove 251 of the lead 250, the organic solderability protective layer 280 is low-cost and does not require expensive metal materials, complex equipment, or process flows, thus reducing manufacturing costs. It also eliminates the use of toxic and hazardous metals, making it highly environmentally friendly. The low processing temperature of the organic solderability protective layer 280 reduces the thermal load on the substrate 300, thereby improving the reliability of the package structure. Furthermore, the processing time of the organic solderability protective layer 280 is short, which helps increase production efficiency.

[0048] See also Figure 1 、 Figure 2G and Figure 2H ,in, Figure 2G 2 is a bottom schematic diagram of a packaging structure formed by cutting along the second cutting lanes 241 between adjacent plastic packaging units 200. Figure 2H It is along Figure 2G In the cross-sectional view along the line A-A1, step S13, cutting is performed along the second cutting lanes 241 between adjacent plastic encapsulation units 200 to form a plurality of independent package structures, wherein the second cutting lanes 241 are covered by the first cutting lanes 240, and the width W3 of the second cutting lanes 241 is less than the width W1 of the first cutting lanes 240. The second cutting lanes 241 overlap with the intervals between adjacent plastic encapsulation units 200, and the package structure formed by cutting along the second cutting lanes 241 between adjacent plastic encapsulation units 200 meets the design requirements. Figure 2E The dashed line is used to depict the boundary of the second cutting street 241 .

[0049] In this step, the frame connecting rib 222 is located in the second cutting path 241. After cutting along the second cutting path 241 between adjacent plastic encapsulation units 200, the frame connecting rib 222 is removed, and the plastic encapsulation body 270 located in the second cutting path 241 is removed. The connection between the pin 250 and the frame connecting rib 222 is exposed on the side of the packaging structure.

[0050] In some embodiments, the width W1 of the first cutting street 240 is greater than the width W2 of the frame connecting rib 222, the width W3 of the second cutting street 241 is less than the width W1 of the first cutting street 240, and the width W3 of the second cutting street 241 is greater than or equal to the width W2 of the frame connecting rib 222, that is, W1>W3≥W2.

[0051] The manufacturing method provided by the embodiment of the present invention is a two-step process to ultimately form the package structure. The manufacturing method provided by the embodiment of the present invention utilizes the selectivity of the organic solderability protective layer 280 to protect the stepped cut groove 251 of the lead, eliminating the need for 100% tin plating in the stepped cut groove 251 of the lead to achieve the purpose of protection. This eliminates the need for an electroplating process, significantly reducing manufacturing costs and preventing environmental pollution.

[0052] Based on the same inventive concept, an embodiment of the present invention further provides a packaging structure manufactured using the above manufacturing method. Figures 2A to 2H , a packaging structure provided by an embodiment of the present invention includes: a plastic package 270; a lead frame, which is covered by the plastic package 270, and the lead frame includes a pin 250, the bottom surface of the pin 250 is exposed to the bottom surface of the plastic package 270, the side surface of the pin 250 is exposed to the side surface of the plastic package 270, and the side surface of the pin 250 has a step cutting groove 251; a chip (not shown in the drawings), which is covered by the plastic package 270, and the chip is electrically connected to the pin 250; a pre-coated metal layer 230, which covers the bottom surface of the pin 250, and the material of the pre-coated metal layer 230 is different from that of the lead frame; an organic solderability protective layer 280, which covers the surface of the step cutting groove 251 of the pin 250 from the connection between the side surface of the pin 250 and the bottom surface of the pin 250.

[0053] In the packaging structure provided in an embodiment of the present invention, the bottom surface of the pin 250 is covered with a pre-coated metal layer 230, and the organic solderability protective layer 280 covers the surface of the stepped cutting groove 251 of the pin 250 from the connection between the side surface of the pin 250 and the bottom surface of the pin 250. The organic solderability protective layer 280 can prevent the surface of the stepped cutting groove 251 of the pin 250 from being oxidized. When the packaging structure is welded to other devices (such as a PCB board), the solder can be welded to the lead frame at the stepped cutting groove 251, so that a 100% optical inspection can be performed from the side of the packaging structure to verify the integrity of the solder joint connection, thereby achieving the purpose of verifying the electrical connection and ensuring that the pin can be successfully welded to other devices, such as a printed circuit board (PCB). The packaging structure provided by the embodiment of the present invention only utilizes the selective covering of the organic solderability protective layer 280 to achieve protection of the surface of the stepped cutting groove 251 of the pin 250. There is no need to perform 100% tin plating at the stepped cutting groove 251 of the pin 250 to achieve the purpose of protection. There is no need to perform the electroplating process, which greatly reduces the manufacturing cost and does not cause environmental pollution.

[0054] In some embodiments, the lead frame also includes a base island 221, the pins 250 are distributed around the base island 221, the back of the chip is mounted on the base island 221, the front of the chip is electrically connected to the pins 250 through welding wires, and the pre-coated metal layer 230 also covers the bottom surface of the base island 221 of the lead frame.

[0055] In some embodiments, the side of the plastic package 270 has a stepped cutting groove 271, and the stepped cutting groove 251 of the pin 250 is located on the extension path of the stepped cutting groove 271 of the plastic package 270. Based on the same inventive concept, an embodiment of the present invention also provides an electronic device using the packaging structure. Figure 3 This is a schematic diagram of an electronic device provided by an embodiment of the present invention. Figures 2A to 2H as well as Figure 3 The electronic device includes a substrate 300 and a package structure 310 disposed on the substrate 300. The package structure 310 adopts the above-mentioned package structure and is electrically connected to the substrate 300 via a solder layer 320. The solder layer 320 covers the pre-coated metal layer 230 on the bottom surface of the pins 250 of the package structure 310 and fills the stepped grooves 251 on the sides of the pins 250. The organic solderability protective layer 280 on the surface of the stepped grooves 251 of the pins 250 can be melted during soldering, allowing the solder layer 320 to be directly soldered to the base material of the pins 250. In some embodiments, the substrate 300 can be a printed circuit board.

[0056] When the package structure 310 is assembled on the substrate 300, the pre-coated metal layer 230 on the bottom surface of the pin 250 of the package structure 310 contacts the solder, and the organic solderability protective layer 280 melts into the solder at the welding temperature, thereby exposing the surface of the lead frame substrate with strong activity. The solder can fill the step cutting groove 251 and weld with the substrate exposed at the step cutting groove 251. After the assembly is completed, the step cutting groove 251 of the package structure 310 is filled with solder, so that a 100% optical inspection can be performed from the side of the package structure to verify the integrity of the solder joint connection, thereby achieving the purpose of verifying the electrical connection and ensuring that the pin / terminal can be successfully soldered to the printed circuit board (PCB).

[0057] It should be noted that the terms "including," "having," and their variations, as used in this document, are intended to cover non-exclusive inclusions. Terms such as "first," "second," and the like are used to distinguish similar items and are not necessarily used to describe a specific order or precedence, unless the context clearly indicates otherwise. Such usage should be understood to be interchangeable where appropriate. The term "one or more" may be used to describe a feature, structure, or characteristic in the singular, or in the plural, depending at least in part on the context, to describe a feature, structure, or combination of features. The term "based on" should be understood as not necessarily intended to express an exclusive set of factors, but may alternatively, also depending at least in part on the context, allow for the presence of other factors that are not necessarily explicitly described. Furthermore, the embodiments of the present invention and the features therein may be combined with one another, unless there is a conflict. Furthermore, descriptions of well-known components and technologies have been omitted from the above description to avoid unnecessary confusion regarding the concepts of the present invention. In each of the above embodiments, each embodiment focuses on its differences from the other embodiments, and reference may be made to the same or similar parts between the embodiments.

[0058] The above description is only a preferred embodiment of the present invention. It should be pointed out that ordinary technicians in this technical field can make several improvements and modifications without departing from the principles of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A method for manufacturing a packaging structure, characterized in that: include: A plastic package structure is provided, comprising an initial plastic package body, a chip, and a lead frame, wherein the chip and the lead frame are encapsulated by the initial plastic package body, the lead frame comprises initial pins, the chip is electrically connected to the initial pins, the bottom surface of the initial pins is covered with a pre-coated metal layer, the pre-coated metal layer is exposed on the bottom surface of the initial plastic package body, and the material of the pre-coated metal layer is different from that of the lead frame, and the plastic package structure is divided into a plurality of plastic package units; Half-cutting the plastic package structure along a first cutting line between adjacent plastic package units from the bottom surface of the plastic package structure to form a lead with a stepped cutting groove on the side surface; Covering with an organic solderability protective layer, wherein the organic solderability protective layer selectively covers the surface of the step cutting groove of the lead; Cutting is performed along second cutting lines between adjacent plastic packaging units to form a plurality of independent packaging structures, wherein the second cutting lines are covered by the first cutting lines, and the width of the second cutting lines is smaller than the width of the first cutting lines.

2. The manufacturing method according to claim 1, characterized in that The lead frame is a pre-plated lead frame, and the pre-coated metal layer is pre-formed on the bottom surface of the lead frame.

3. The manufacturing method according to claim 1, characterized in that The depth of half-cutting the plastic package structure along the first cutting line between adjacent plastic package units is half the thickness of the initial pins.

4. The manufacturing method according to claim 1, characterized in that The step of half-cutting the plastic package structure along the first cutting line between adjacent plastic package units to form a lead with a stepped cutting groove on the side also includes: the initial plastic package body is also cut to form a plastic package body with a stepped cutting groove on the side.

5. The manufacturing method according to claim 1, characterized in that The lead frame also includes frame connecting ribs located between adjacent plastic encapsulation units. In the step of half-cutting the plastic encapsulation structure along the first cutting path between adjacent plastic encapsulation units, the frame connecting ribs are also half-cut; in the step of covering the organic solderability protective layer, the organic solderability protective layer also selectively covers the cut surface of the frame connecting ribs.

6. The manufacturing method according to claim 5, characterized in that The width of the first cutting street is greater than the width of the frame connecting rib, and the width of the second cutting street is greater than or equal to the width of the frame connecting rib.

7. The manufacturing method according to claim 1, characterized in that The material of the lead frame is copper, the pre-cladding metal layer includes a nickel-palladium-gold composite layer, and the organic solderability protection layer includes a nitrogen-containing organic compound.

8. A packaging structure, characterized in that: include: Plastic packaging; A lead frame is covered by the plastic package, the lead frame includes pins, the bottom surface of the pins is exposed to the bottom surface of the plastic package, the side surfaces of the pins are exposed to the side surfaces of the plastic package, and the side surfaces of the pins have step cutting grooves; A chip is covered by the plastic package, and the chip is electrically connected to the pins; a pre-coated metal layer covering the bottom surface of the pin, wherein the material of the pre-coated metal layer is different from that of the lead frame; The organic solderability protective layer covers the surface of the step cutting groove of the lead starting from the connection between the side surface of the lead and the bottom surface of the lead.

9. The packaging structure according to claim 8, wherein: The side surface of the plastic package body is provided with a stepped cutting groove, and the stepped cutting groove of the pin is located on an extension path of the stepped cutting groove of the plastic package body.

10. The packaging structure according to claim 8, wherein: The lead frame also includes a base island, the pins are distributed around the base island, the back of the chip is mounted on the base island, the front of the chip is electrically connected to the pins through welding wires, and the pre-coated metal layer also covers the bottom surface of the base island of the lead frame.

11. An electronic device, characterized in that: The electronic device includes a substrate and a packaging structure arranged on the substrate, the packaging structure adopts the packaging structure described in any one of claims 8 to 10, the packaging structure is electrically connected to the substrate through a solder layer, the solder layer covers the pre-coated metal layer on the bottom surface of the pin of the packaging structure, and fills the stepped cutting groove on the side of the pin, the organic solderability protective layer on the surface of the stepped cutting groove of the pin can be melted during welding, so that the solder layer can be directly welded to the pin substrate.

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