Packaging structure, manufacturing method thereof and electronic device adopting packaging structure

Abstract

The invention provides a packaging structure, a manufacturing method thereof and an electronic device adopting the packaging structure. The manufacturing method comprises the following steps: firstly, covering a pre-covering metal layer on the bottom surface of an initial pin, and then carrying out half cutting on the initial pin to form a pin with a stepped cutting groove, so that a 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 solderable protection layer to prevent the surface of the stepped cutting groove of the pin from being oxidized, so that when the packaging structure is welded with other devices, welding flux can be welded at the stepped cutting groove, 100% optical inspection can be conveniently carried out from the side face of the packaging structure, the integrity of welding spot connection is verified, and the reliability of the packaging structure is improved. The purpose of verifying electrical connection is achieved. According to the manufacturing method, the surface of the stepped cutting groove of the pin is protected only through selective covering of the organic solderable protection layer, an electroplating process does not need to be executed, the manufacturing cost is greatly reduced, and environmental pollution cannot be caused.

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 in tinning 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 the side of the package structure is difficult to tin or the tin climbing height is insufficient is that the pin soldering ends 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 not easy to tin or the tin climbing height is insufficient. In order to solve this problem, the following measures can be taken: before the package process is cut, a step cutting and electroplating process is added to cut the pins 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 welding in the step cutting groove area, so as to perform 100% optical inspection from the side of the package structure to verify the integrity of the solder joint connection, so as to achieve the purpose of verifying the electrical connection and ensure that the pins / terminals can be successfully soldered on the printed circuit board (PCB).

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

[0005] Therefore, how to make the tin creeping height on the side of the packaging structure meet the requirements, reduce costs, and not cause 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 make the tin creeping height of the side of the packaging structure meet the requirements, reduce costs, and will not cause environmental pollution.

[0007] In order to solve the above problems, the present invention provides a method for manufacturing a packaging structure, which comprises: providing a plastic packaging structure, the plastic packaging structure comprising 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 comprises 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; half-cutting the plastic packaging structure along a first cutting path 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 path between adjacent plastic packaging units to form a plurality of independent packaging structures, wherein the second cutting path is covered by the first cutting path, and the width of the second cutting path is smaller than the width of the first cutting path.

[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 pin.

[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 also 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 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 cutting 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 material of the lead frame is 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 step cutting groove, and the step cutting groove of the lead is located on an extension path of the step cutting groove of the plastic package body.

[0016] In one embodiment, the lead frame also includes a base island, the pins are distributed around the base island, the back side of the chip is mounted on the base island, the front side of the chip is electrically connected to the pins via welding 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 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.

[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, and then half-cuts the initial pin to form a pin with a step cutting groove, so that the base material (such as copper) of the pin is exposed at the step cutting groove of the pin; and then covers the organic solderability protective layer, the organic solderability protective layer can selectively cover the surface of the step cutting groove, and the organic solderability protective layer can prevent the surface of the step cutting groove of the pin from being oxidized, and then when the package structure manufactured by the manufacturing method of the present invention is welded with other devices (such as PCB boards), the solder can be welded at the step cutting groove, so as to perform 100% optical inspection from the side of the package structure to verify the integrity of the solder joint connection, so as to achieve the purpose of verifying the electrical connection, and ensure that the pin can be successfully welded on 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 realize the protection of the step cutting groove surface of the pin, and does not need to perform 100% tin plating at the step cutting groove of the pin to achieve the purpose of protection, and does not need to perform electroplating process, which greatly reduces the manufacturing cost and does not cause environmental pollution. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for describing the embodiments. Obviously, the drawings described below are only some embodiments of the present invention, and for ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0020] Figure 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 a process flow of a method for manufacturing a package structure provided by an embodiment of the present invention;

[0022] Figure 2B is along Figure 2A A cross-sectional view of line A-A1;

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

[0024] Figure 2D is along Figure 2C A cross-sectional view of line A-A1;

[0025] Figure 2E It 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 is along Figure 2E A cross-sectional view of line A-A1;

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

[0028] Figure 2H is along Figure 2G A cross-sectional view 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 provided by the present invention, and specific implementation methods of the electronic device using the packaging structure are described in detail below with reference to the accompanying drawings.

[0031] Figure 1 is a schematic diagram of the steps of a method for manufacturing a packaging structure provided by 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 includes 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 path 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 covers the surface of the stepped cutting groove of the pin; step S13, cutting along a second cutting path between adjacent plastic packaging units to form a plurality of independent packaging structures, wherein the second cutting path is covered by the first cutting path, and the width of the second cutting path is smaller than the width of the first cutting path.

[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, and then half-cuts the initial pin to form a pin with a step cutting groove, so that the base material (such as copper) of the pin is exposed at the step cutting groove of the pin; and then covers the organic solderability protective layer, the organic solderability protective layer can selectively cover the surface of the step cutting groove, and the organic solderability protective layer can prevent the surface of the step cutting groove of the pin from being oxidized, and then when the package structure manufactured by the manufacturing method of the present invention is welded with other devices (such as PCB boards), the solder can be welded at the step cutting groove, so as to perform 100% optical inspection from the side of the package structure to verify the integrity of the solder joint connection, so as to achieve the purpose of verifying the electrical connection, and ensure that the pin can be successfully welded on 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 realize the protection of the step cutting groove surface of the pin, and does not need to perform 100% tin plating at the step cutting groove of the pin to achieve the purpose of protection, and does not need to perform electroplating process, which greatly reduces the manufacturing cost and does not cause environmental pollution.

[0033] Figure 2A to Figure 2H It is a process flow chart of a method for manufacturing a packaging structure provided by an 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 is along Figure 2A The cross-sectional view along the A-A1 line in the figure, step S10, provides a plastic packaging structure, the plastic packaging structure includes an initial plastic packaging body 210, a chip (not shown in the figure) 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, and 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, and in this embodiment, the lead frame is a copper-based lead frame. In the manufacturing process, after the copper-based lead frame is cut, its cut surface exposes the copper substrate, and 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 a plurality of frame units (not shown in the drawings), each of which is covered by the initial plastic encapsulation body 210 to form the plastic encapsulation unit 200. Adjacent frame units are connected by frame connecting ribs 222, that is, the lead frame includes frame connecting ribs 222 located between adjacent plastic encapsulation units 200. In this embodiment, the initial plastic encapsulation body 210 not only covers the frame units, but also covers the frame connecting ribs 222.

[0037] Each of the plastic encapsulation 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 encapsulation structure, the initial pins 220 can extend from the internal area of ​​the plastic encapsulation unit 200 to the side of the plastic encapsulation unit 200, and be connected to the frame connecting rib 222 at the side of the plastic encapsulation 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 encapsulation 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-plated lead frame (Pre-Plating frame Finish, PPF for short), that is, before the lead frame is encapsulated with a plastic encapsulation 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 also 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 the material of the lead frame. For example, in this embodiment, the material of the lead frame is 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 composite layer of multiple metal layers. 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 encapsulation structure after half-cutting along the first cutting line 240 between adjacent plastic encapsulation units 200. Figure 2D is along Figure 2C In the cross-sectional view along the A-A1 line, step S11, the plastic encapsulation structure is half-cut from the bottom surface of the plastic encapsulation structure along the first cutting path 240 between adjacent plastic encapsulation units 200 to form a pin 250 with a stepped cutting groove 251 on the side. In this step, in the present embodiment, the plastic encapsulation structure is cut from the bottom surface of the plastic encapsulation structure along the first cutting path 240, 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 of the plastic encapsulation units 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 of the plastic encapsulation units 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 plastic package structure, and the cutting depth is less than the thickness of the initial pin 220, so as to form a pin 250 with a stepped cutting groove 251 on the side. In some embodiments, the depth of half-cutting the plastic package structure along the first cutting path 240 between adjacent plastic package units 200 is half the thickness of the initial pin 220. In this step, in the direction perpendicular to the surface of the plastic package structure, the plastic package structure is not completely divided, and the cutting surface only exposes part of the side of the pin 250 to form the stepped cutting groove 251 of the pin 250. The surface of the stepped cutting groove 251 of the pin 250 exposes the substrate of the lead frame. For example, in this embodiment, the surface of the stepped cutting groove 251 of the pin 250 exposes the copper substrate of the lead frame.

[0041] In some embodiments, when the plastic encapsulation structure is half-cut along the first cutting path 240 between adjacent plastic encapsulation units 200, the initial plastic encapsulation body 210 is also cut, and a stepped cutting groove 271 is formed on the side of the plastic encapsulation body 270. In some embodiments, when the plastic encapsulation structure is half-cut along the first cutting path 240 between adjacent plastic encapsulation units 200, the initial plastic encapsulation body 210 and the initial pin 220 are cut at the same time, 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 encapsulation 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 path 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 a step cutting groove 251 of the lead 250 and a step cutting groove 271 of the plastic package body 270. The width W2 of the frame connecting rib 222 is equal to the width W2 of the second cutting path 241 (indicated at Figure 2E ) have 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 is a schematic diagram of the bottom surface after being covered with an organic solderability protective layer 280. Figure 2F is along Figure 2G In the cross-sectional view along the line A-A1, step S12, covering the organic solderability protection layer 280, the organic solderability protection 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 only cover a certain metal surface. For example, in this embodiment, the surface of the step cutting groove 251 of the pin 250 is a copper surface, and a material that only covers the copper surface is selected as the material of the organic solderability preservative 280, so that the organic solderability preservative 280 only covers the surface of the step cutting groove 251 of the pin 250, and does not cover the surface of the pre-coated metal layer 230. In some embodiments, the organic solderability preservative 280 includes a nitrogen-containing organic compound, for example, the organic solderability preservative 280 is one of benzatotriazoles or imidazole organic crystalline bases. In other embodiments, if the surface of the step cutting groove 251 of the pin 250 is other metal surfaces, an organic coating that selectively covers the 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 surface of the step cutting groove 251 of the pin 250 is covered with the organic solderability protective layer 280, so that the surface of the step cutting groove 251 of the pin 250 can be prevented from being oxidized. In the process of assembling the package structure to other devices (such as a printed circuit board), when performing reflow soldering, the organic solderability protective layer 280 can be easily melted into the solder, and at the same time, the copper surface with strong activity is exposed, so that the solder can be welded with the surface of the step cutting groove 251. In addition, compared with forming an electroplating layer on the surface of the step cutting groove 251 of the pin 250, the organic solderability protective layer 280 has low cost, does not require expensive metal materials, does not require complex equipment and process flow, reduces manufacturing costs, and does not require the use of toxic and harmful metals, and has high environmental friendliness; the processing temperature of the organic solderability protective layer 280 is low, so that the heat load of the substrate 300 is small, which is conducive to improving the reliability of the package structure; at the same time, the process processing time of the organic solderability protective layer 280 is short, which is conducive to increasing production efficiency.

[0048] See also Figure 1 , Figure 2G and Figure 2H ,in, Figure 2G is a bottom schematic diagram of a packaging structure formed by cutting along the second cutting road 241 between adjacent plastic packaging units 200. Figure 2H is along Figure 2G In the cross-sectional view along the A-A1 line, step S13, cutting is performed along the second cutting path 241 between adjacent plastic encapsulation units 200 to form a plurality of independent packaging structures, wherein the second cutting path 241 is covered by the first cutting path 240, and the width W3 of the second cutting path 241 is smaller than the width W1 of the first cutting path 240. The second cutting path 241 overlaps with the interval between the adjacent plastic encapsulation units 200, and the packaging structure formed by cutting along the second cutting path 241 between the adjacent plastic encapsulation units 200 meets the design requirements. Figure 2E The dashed line is used to illustrate 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, the plastic encapsulation body 270 located in the second cutting path 241 is removed, and the connection between the pin 250 and the frame connecting rib 222 is exposed to the side of the packaging structure.

[0050] In some embodiments, the width W1 of the first cutting path 240 is greater than the width W2 of the frame connecting rib 222, the width W3 of the second cutting path 241 is less than the width W1 of the first cutting path 240, and the width W3 of the second cutting path 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 cut twice to finally form the packaging 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 step cutting groove 251 of the pin, and does not need to perform 100% tin plating at the step cutting groove 251 of the pin to achieve the purpose of protection, and does not need to perform electroplating process, which greatly reduces the manufacturing cost and does not cause environmental pollution.

[0052] Based on the same inventive concept, an embodiment of the present invention also provides a packaging structure manufactured by the above manufacturing method. Figure 2A to Figure 2H The 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 the 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 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. The organic solderability protective layer 280 can prevent the surface of the step cutting groove 251 of the pin 250 from being oxidized, and then 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 step cutting groove 251, so as to perform 100% optical inspection 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 protection 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 an 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 side of the chip is mounted on the base island 221, the front side 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 is a schematic diagram of an electronic device provided by an embodiment of the present invention, please refer to Figure 2A to Figure 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. The package structure is electrically connected to the substrate 300 through a solder layer 320. The solder layer 320 covers the pre-coated metal layer 230 on the bottom surface of the pin 250 of the package structure 310 and fills the step cutting groove 251 on the side of the pin 250. The organic solderability protective layer 280 on the surface of the step cutting groove 251 of the pin 250 can be melted during welding, so that the solder layer 320 is directly welded and connected to the base material of the pin 250. In some embodiments, the substrate 300 can be a printed circuit board.

[0056] When the packaging structure 310 is assembled on the substrate 300, the pre-coated metal layer 230 on the bottom surface of the pin 250 of the packaging 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 be filled in the step cutting groove 251 and welded to the substrate exposed at the step cutting groove 251. After the assembly is completed, the step cutting groove 251 of the packaging structure 310 is filled with solder, so as to perform 100% optical inspection from the side of the packaging structure to verify the integrity of the solder joint connection, so as to achieve the purpose of verifying the electrical connection and ensure that the pin / terminal can be successfully soldered to the printed circuit board (PCB).

[0057] It should be noted that the terms "including" and "having" and their variations involved in the document of the present invention are intended to cover non-exclusive inclusions. The terms "first", "second", etc. are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence, unless the context clearly indicates, and it should be understood that the data used in this way can be interchanged under appropriate circumstances. The term "one or more" depends at least in part on the context, and can be used to describe features, structures or characteristics in a singular sense, or can be used to describe features, structures or combinations of features in a plural sense. The term "based on" can be understood as not necessarily intended to express a set of exclusive factors, but can alternatively, also at least in part depending on the context, allow the presence of other factors that are not necessarily explicitly described. In addition, the embodiments of the present invention and the features in the embodiments can be combined with each other without conflict. In addition, in the above description, the description of well-known components and technologies is omitted to avoid unnecessary confusion of the concept of the present invention. In the above embodiments, each embodiment focuses on the differences from other embodiments, and the same / similar parts between the embodiments can be referred to each other.

[0058] The above 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 principle 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 packaging structure is provided, the plastic packaging structure comprising 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 comprises 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 that of the lead frame, and the plastic packaging structure is divided into a plurality of plastic packaging units; Half-cutting the plastic package structure along a first cutting path between adjacent plastic package units from the bottom surface of the plastic package structure to form a lead having a stepped cutting groove on the side surface; Covering with an organic solderability protective layer, 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 encapsulation 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 encapsulation structure along the first cutting line between adjacent plastic encapsulation units is half the thickness of the initial pin.

4. The manufacturing method according to claim 1, characterized in that: The step of half-cutting the plastic package structure along the first cutting path 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 cutting surface of the frame connecting ribs.

6. The manufacturing method according to claim 5, characterized in that: The width of the first cutting road is greater than the width of the frame connecting rib, and the width of the second cutting road 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-coated 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 sealing body; A lead frame is covered by the plastic package body, the lead frame comprises 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 stepped cutting groove; The chip is covered by the plastic package, and the chip is electrically connected to the pins. A pre-coated metal layer covers the bottom surface of the pin, and the material of the pre-coated metal layer is different from that of the lead frame; The organic solderability protection layer covers the stepped cutting groove surface of the lead 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, characterized in that: The side surface of the plastic package body is provided with a step cutting groove, and the step cutting groove of the pin is located on the extension path of the step cutting groove of the plastic package body.

10. The packaging structure according to claim 8, characterized in that: 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 claims 8-10, 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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