Package structure and forming method thereof

Abstract

A packaging structure and a forming method thereof are provided, the forming method of the packaging structure includes the following steps: forming a plurality of slots on a surface of a lead frame, the lead frame including a plurality of pins, and the slots are arranged on one side of each pin; arranging a metal paste body in the open groove; heating the metal paste to form a weldable part in each slot; and cutting the plurality of cutting channels of the lead frame to form a packaging structure. The weldable part wraps one side of each pin. Therefore, the soldering tin area of the side edge of the packaging structure can be increased, and the connection strength of the packaging structure and the circuit board can be improved.

Description

Technical Field

[0001] The present disclosure relates to a package structure and a method for forming the same, and more particularly to a package structure and a method for forming the same that can increase the solderable area of the side surfaces. Background Art

[0002] Generally speaking, after cutting, the copper surface of a Quad Flat No Leads (QFN) package is exposed, resulting in insufficient solderable area on the side of the lead. This leads to insufficient solder strength during subsequent installation on the circuit board, which in turn reduces the life of the circuit board. Specifically, solder fatigue or solder cracks often occur on the side and bottom surfaces of the lead, leading to package defects.

[0003] Therefore, developing a packaging structure and a method for forming the same that can simultaneously improve soldering stability and increase board-level life has become an important and urgent problem in the industry. Summary of the Invention

[0004] The present disclosure provides a packaging structure and a method for forming the same, wherein a solderable portion completely covers one side of a lead to increase the solderable area of the side surface, thereby enhancing the subsequent connection strength with a circuit board.

[0005] According to one embodiment of the present disclosure, a method for forming a package structure is provided, comprising the following steps: forming a plurality of slots on a surface of a lead frame, wherein the lead frame includes a plurality of pins, and the slots are disposed on one side of each pin; disposing a metal paste in the slots; heating the metal paste to form a solderable portion in each slot; and cutting a plurality of cut streets on the lead frame to form a package structure. The solderable portion covers one side of each pin.

[0006] The method for forming the package structure according to the embodiment described in the previous paragraph may further include the following steps: disposing a plastic packaging material on the lead frame.

[0007] According to the method for forming the package structure of the embodiment described in the previous paragraph, the slot can be set between each lead and each dicing street.

[0008] According to the method for forming the package structure of the embodiment described in the previous paragraph, a laser beam may be used to form grooves on the surface of the lead frame.

[0009] According to the method for forming the package structure of the embodiment described in the previous paragraph, the grooves can be connected to each other.

[0010] According to the method for forming the package structure of the embodiment described in the previous paragraph, a gap may be provided between every two of the slots.

[0011] According to the method for forming the package structure of the embodiment described in the previous paragraph, the metal paste can be directly disposed in each slot, and the volume of the metal paste corresponds to the volume of each slot.

[0012] According to the method for forming the package structure of the embodiment described in the previous paragraph, the metal paste may be further disposed on a surface of a chip pad of the lead frame.

[0013] According to the method for forming the package structure of the embodiment described in the previous paragraph, the width of each slot can be 0.1 mm to 10 mm.

[0014] According to the method for forming the package structure of the embodiment described in the previous paragraph, the metal paste can be placed in the groove through a mold.

[0015] According to one embodiment of the present disclosure, a method for forming a package structure is provided, comprising the following steps: forming at least one slot in a surface of a lead frame, wherein the lead frame includes a plurality of pins, and the slot is disposed on a side of at least one of the pins; disposing a metal paste in the slot; heating the metal paste to form a solderable portion in the slot; and cutting a plurality of cut lines on the lead frame to form a package structure. The solderable portion covers a side of at least one of the pins.

[0016] The method for forming the package structure according to the embodiment described in the previous paragraph may further include the following steps: disposing a plastic packaging material on the lead frame; and disposing a shielding element on a surface of the plastic packaging material or a surface of the lead frame.

[0017] According to one embodiment of the present disclosure, a package structure is provided, comprising a lead frame, a semiconductor chip, a plastic encapsulation material, and a solderable portion. The lead frame includes a die holder and a plurality of pins, wherein the pins are disposed around the die holder. The semiconductor chip is disposed on the die holder of the lead frame. The plastic encapsulation material is disposed on the lead frame. The solderable portion covers a surface of at least one of the pins.

[0018] The packaging structure according to the embodiment described in the previous paragraph may further include a shielding element, wherein the shielding element is disposed on a surface of the plastic packaging material or a surface of the lead frame.

[0019] According to the packaging structure of the embodiment described in the previous paragraph, the shielding element may be an electromagnetic interference shielding element.

[0020] The package structure according to the embodiment described in the previous paragraph may further include an isolation layer, wherein the isolation layer is disposed on one side of at least another one of the leads.

[0021] According to the packaging structure of the embodiment described in the previous paragraph, the solderable portion can be made of a tin alloy.

[0022] According to the package structure of the embodiment described in the previous paragraph, the solderable portion may cover the surface of each pin. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 FIG2 is a schematic flow chart illustrating a method for forming a package structure according to a first embodiment of the present invention;

[0024] Figure 2 Draw Figure 1 Schematic diagram of the steps in the first embodiment;

[0025] Figure 3 Draw Figure 2 A schematic cross-sectional view of the lead frame along section line 3-3 in the first embodiment;

[0026] Figure 4 Draw Figure 1 Schematic diagram of the steps in the first embodiment;

[0027] Figure 5 Draw Figure 4 A schematic cross-sectional view of the lead frame along section line 5-5 in the first embodiment;

[0028] Figure 6 Draw Figure 1 Schematic diagram of the steps in the first embodiment;

[0029] Figure 7 Draw Figure 6 A schematic cross-sectional view of the lead frame along section line 7-7 in the first embodiment;

[0030] Figure 8 Draw Figure 1 Schematic diagram of the steps in the first embodiment;

[0031] Figure 9 Draw Figure 8 A schematic cross-sectional view of the package structure along section line 9-9 in the first embodiment;

[0032] Figure 10 Draw Figure 1 A front view schematic diagram of the packaging structure in the first embodiment;

[0033] Figure 11 Draw Figure 1 A schematic diagram of the back side of the packaging structure in the first embodiment;

[0034] Figure 12 Draw Figure 1 A partial schematic diagram of the packaging structure in the first embodiment;

[0035] Figure 13 Draw Figure 1 A side view of the packaging structure in the first embodiment;

[0036] Figure 14 Draw Figure 1 A side view of the package structure after soldering in the first embodiment;

[0037] Figure 15 Draw Figure 14 A partial side view of the package structure after soldering in the first embodiment;

[0038] Figure 16 FIG2 is a schematic flow chart illustrating a method for forming a package structure according to a second embodiment of the present invention;

[0039] Figure 17 Draw Figure 16 Schematic diagram of steps in the second embodiment;

[0040] Figure 18 Draw Figure 17 A schematic cross-sectional view of the lead frame along section line 18-18 in the second embodiment;

[0041] Figure 19 Draw Figure 16 Schematic diagram of steps in the second embodiment;

[0042] Figure 20 Draw Figure 19 A schematic cross-sectional view of the lead frame along section line 20-20 in the second embodiment;

[0043] Figure 21 Draw Figure 16 Schematic diagram of steps in the second embodiment;

[0044] Figure 22 Draw Figure 21 A schematic cross-sectional view of the lead frame along section line 22-22 in the second embodiment;

[0045] Figure 23 Draw Figure 16 Schematic diagram of steps in the second embodiment;

[0046] Figure 24 Draw Figure 23 A schematic cross-sectional view of the packaging structure along section line 24-24 in the second embodiment;

[0047] Figure 25 Draw Figure 16 A front view schematic diagram of the packaging structure in the second embodiment;

[0048] Figure 26 Draw Figure 16 A schematic diagram of the back side of the packaging structure in the second embodiment;

[0049] Figure 27 Draw Figure 16 A partial schematic diagram of the packaging structure in the second embodiment;

[0050] Figure 28 Draw Figure 16 A side view of the packaging structure in the second embodiment;

[0051] Figure 29 Draw Figure 16 A side view of the packaging structure after soldering in the second embodiment;

[0052] Figure 30 Draw Figure 29 A partial side view of the package structure after soldering in the second embodiment;

[0053] Figure 31 FIG. 1 is a schematic flow chart illustrating a method for forming a package structure according to a third embodiment of the present invention;

[0054] Figure 32 Draw Figure 31 Schematic diagram of steps in the third embodiment;

[0055] Figure 33 Draw Figure 32 A schematic cross-sectional view of the lead frame along section line 33-33 in the third embodiment;

[0056] Figure 34 Draw Figure 31 Schematic diagram of steps in the third embodiment;

[0057] Figure 35 Draw Figure 34 A schematic cross-sectional view of the lead frame along section line 35-35 in the third embodiment;

[0058] Figure 36 Draw Figure 31 Schematic diagram of steps in the third embodiment;

[0059] Figure 37 Draw Figure 36 A schematic cross-sectional view of the package structure along section line 37-37 in the third embodiment;

[0060] Figure 38 Draw Figure 31 A front view schematic diagram of the packaging structure in the third embodiment;

[0061] Figure 39 Draw Figure 31 A schematic diagram of the back side of the packaging structure in the third embodiment;

[0062] Figure 40 Draw Figure 31 A partial schematic diagram of the packaging structure in the third embodiment;

[0063] Figure 41 A partial schematic diagram illustrating a method for forming a package structure according to a fourth embodiment of the present invention is shown;

[0064] Figure 42 Draw Figure 41 A schematic cross-sectional view of the lead frame along the section line 42-42 in the fourth embodiment;

[0065] Figure 43 Draw Figure 41 A front view schematic diagram of the packaging structure in the fourth embodiment;

[0066] Figure 44 Draw Figure 41 A schematic diagram of the back side of the packaging structure in the fourth embodiment;

[0067] Figure 45 Draw Figure 41 A partial schematic diagram of the packaging structure in the fourth embodiment;

[0068] Figure 46 A partial schematic diagram illustrating a method for forming a package structure according to a fifth embodiment of the present invention is shown;

[0069] Figure 47 Draw Figure 46 A schematic cross-sectional view of the lead frame along section line 47-47 in the fifth embodiment;

[0070] Figure 48 Draw Figure 46 Another partial schematic diagram of the method for forming a package structure in the fifth embodiment;

[0071] Figure 49 Draw Figure 48 A schematic cross-sectional view of the lead frame along section line 49-49 in the fifth embodiment;

[0072] Figure 50 Draw Figure 46 A front view schematic diagram of the packaging structure in the fifth embodiment;

[0073] Figure 51 Draw Figure 46 A schematic diagram of the back side of the packaging structure in the fifth embodiment; and

[0074] Figure 52 Draw Figure 46 Partial schematic diagram of the packaging structure in the fifth embodiment.

[0075] The description of the accompanying drawings is as follows:

[0076] 100, 200, 300, 400, 500: packaging structure

[0077] 110, 210, 310: lead frame

[0078] 110a, 210a: surface

[0079] 111, 211, 311, 411, 511: pins

[0080] 112, 212, 312, 512: cutting path

[0081] 113, 213, 313, 413, 513: chip holder

[0082] 120, 220, 320, 420, 520: Plastic packaging materials

[0083] 130, 230, 330, 430, 530: weldable parts

[0084] 340, 440, 540: shielding elements

[0085] 350, 450, 550: insulation layer

[0086] S100, S200, S300: Method for forming packaging structure

[0087] S101, S102, S103, S104, S105, S201, S202, S203, S204, S205, S301, S302, S303, S304, S305, S306: Steps

[0088] L: Laser beam

[0089] MP: Metal Paste

[0090] S: slotted

[0091] SN: Soldering Department

[0092] ST: Mould DETAILED DESCRIPTION

[0093] Please refer to Figure 1 , which illustrates a flow chart of a method S100 for forming a package structure according to the first embodiment of the present invention. Figure 1 It can be seen that the method S100 for forming a package structure includes steps S101 , S102 , S103 , S104 , and S105 .

[0094] Please refer to Figure 2 and Figure 3 ,in Figure 2 Draw Figure 1 Schematic diagram of steps S101 and S102 in the first embodiment, Figure 3 Draw Figure 2 A schematic cross-sectional view of the lead frame 110 along the section line 3-3 in the first embodiment. Figures 1 to 3As can be seen, step S101 includes applying a plastic encapsulating material 120 to a lead frame 110, and step S102 includes forming a plurality of slots S on a surface 110a of the lead frame 110. The lead frame 110 includes a plurality of pins 111 and a plurality of scribe lines 112, and the slots S are disposed on one side of each pin 111. Specifically, the surface 110a of the lead frame 110 is the lower surface of the lead frame 110 not covered by the plastic encapsulating material 120.

[0095] Furthermore, in step S102, a laser beam L is used to remove a portion of the lead frame 110 to form slots S on the surface 110a of the lead frame 110. The slots S are located between each lead 111 and each scribe line 112, and the slots S are interconnected, thereby forming a continuous groove around each unit area of the lead frame 110. Each unit area of the lead frame 110 refers to a complete area formed by the leads 111 surrounding the wafer pad 113, but the present invention is not limited thereto. It should be noted that before step S101 is performed, a step such as placing a semiconductor chip (not shown) on the wafer pad 113 of the lead frame 110 may be included.

[0096] In the first embodiment, the width of each slot S may be 0.1 mm to 10 mm, but is not limited thereto.

[0097] Please refer to Figure 4 and Figure 5 ,in Figure 4 Draw Figure 1 Schematic diagram of step S103 in the first embodiment, Figure 5 Draw Figure 4 A schematic cross-sectional view of the lead frame 110 along the section line 5-5 in the first embodiment. Figure 1 and Figure 4 、 Figure 5 As can be seen, step S103 includes placing a metal paste MP in the slot S, wherein the metal paste MP can be placed in the slot S using a mold ST. Specifically, in step S103, the metal paste MP is precisely placed in the slot S corresponding to one side of the pin 111 by printing through multiple openings of the mold ST, and the metal paste MP completely covers the surface of the pin 111. The metal paste MP may contain tin and may be a high-melting-point metal paste to prevent melting during subsequent processes.

[0098] It should be noted that the metal paste MP can be further disposed on the surface of the wafer pad 113 and the bottom surface of each lead 111, wherein the surface of the wafer pad 113, the bottom surface of each lead 111, and the surface 110a of the lead frame 110 are on the same side. This can enhance the connection strength during subsequent installation on a circuit board, improve board-level reliability, and further save electroplating steps.

[0099] Please refer to Figure 6 and Figure 7 ,in Figure 6 Draw Figure 1 Schematic diagram of step S104 in the first embodiment, Figure 7 Draw Figure 6 A schematic cross-sectional view of the lead frame 110 along the section line 7-7 in the first embodiment. Figure 1 and Figure 6 、 Figure 7 It can be seen that step S104 includes heating the metal paste MP to form a solderable portion 130 in each slot S, and the solderable portion 130 covers one side of each pin 111, wherein step S104 heats the metal paste MP to form the solderable portion 130 by reflowing, thereby fixing the solderable portion 130 to the surface of the pin 111.

[0100] Please refer to Figures 8 to 11 , Figure 8 Draw Figure 1 Schematic diagram of step S105 in the first embodiment, Figure 9 Draw Figure 8 A schematic cross-sectional view of the package structure 100 along section line 9-9 in the first embodiment, Figure 10 Draw Figure 1 A front view of the package structure 100 in the first embodiment, Figure 11 Draw Figure 1 The back side view of the package structure 100 in the first embodiment. Figure 1 and Figures 8 to 11 It can be seen that step S105 includes cutting the cutting line 112 (shown in FIG. Figure 2 ) to form the package structure 100, wherein the cutting streets 112 of the lead frame 110 can be cut by a knife, and the cutting width can be wider than or equal to the width of the cutting streets 112.

[0101] Furthermore, since the depth of the slot S formed by the laser beam L in step S102 is greater than the thickness of each pin 111, the solderable portion 130 can completely cover the surface of the pin 111. When the package structure 100 is formed in step S105, there is no exposed copper surface on the surface of the pin 111, thereby increasing the solderable area of the side edges of the package structure 100 and further improving the connection strength between the package structure 100 and the circuit board.

[0102] Please refer to Figure 12 and Figure 13 ,in Figure 12 Draw Figure 1 A partial schematic diagram of the package structure 100 in the first embodiment, Figure 13 Draw Figure 1 A side view of the package structure 100 in the first embodiment. Figures 10 to 13 As can be seen, the package structure 100 includes a lead frame 110, a semiconductor chip, a plastic encapsulating material 120, and a solderable portion 130, wherein the plastic encapsulating material 120 is disposed on the lead frame 110. The lead frame 110 includes a die pad 113 and pins 111, wherein the pins 111 are disposed around the die pad 113. The semiconductor chip is disposed on the die pad 113 of the lead frame 110, and the solderable portion 130 covers the surface of each pin 111.

[0103] By completely covering the surface of each lead 111 with the solderable portion 130, copper exposure on the lead 111 surface is completely avoided, thereby increasing the solderable area on the side edges of the package structure 100 and further improving board-level reliability for widespread application in automotive products. It should be noted that automotive products place high demands on the board-level reliability of the package structure.

[0104] Furthermore, the solderable portion 130 can be made of a tin alloy. Specifically, the package structure 100 provides a high degree of flexibility in selecting the material of the solderable portion 130 , that is, the material of the solderable portion 130 can be flexibly selected according to the packaging requirements. Thus, it can be adapted to different packaging requirements.

[0105] Please refer to Figure 14 and Figure 15 ,in Figure 14 Draw Figure 1 A side view of the package structure 100 after soldering in the first embodiment. Figure 15 Draw Figure 14 A partial side view of the package structure 100 after soldering in the first embodiment. Figure 14 and Figure 15It can be seen that when the package structure 100 is connected to the circuit board via a solder portion SN, since the solderable portion 130 completely covers the surface of each pin 111, the solder portion SN can be set over a wide range, that is, the side of each pin 111 has a large solderable area, thereby improving the connection strength with the circuit board.

[0106] It must be noted that the thickness of the metal paste MP, the thickness of the weldable portion 130 and the width of the slot S in the first embodiment are only used to illustrate their arrangement relationship and are not actual thicknesses and widths.

[0107] Please refer to Figure 16 , which illustrates a flow chart of a method S200 for forming a package structure according to a second embodiment of the present invention. Figure 16 It can be seen that the method S200 for forming a package structure includes steps S201 , S202 , S203 , S204 , and S205 .

[0108] Please refer to Figure 17 and Figure 18 ,in Figure 17 Draw Figure 16 Schematic diagram of steps S201 and S202 in the second embodiment, Figure 18 Draw Figure 17 A schematic cross-sectional view of the lead frame 210 along the section line 18-18 in the second embodiment. Figures 16 to 18 It can be seen that step S201 includes disposing a plastic packaging material 220 on the lead frame 210, and step S202 includes forming a plurality of slots S on a surface 210a of the lead frame 210, wherein the lead frame 210 includes a plurality of pins 211 and a plurality of cutting streets 212, and the slots S are disposed on one side of each pin 211.

[0109] Furthermore, in step S202, a laser beam L is used to form slots S on the surface 210a of the lead frame 210. The slots S are disposed between each lead 211 and each scribe line 212, and a gap is formed between each two slots S. The plastic packaging material 220 is located in the gaps between the slots S. The laser beam L can be a dual-frequency Nd-YAG laser light source with a wavelength of 532nm, a UV nanosecond pulse, or a picosecond laser.

[0110] Please refer to Figure 19 and Figure 20 ,in Figure 19 Draw Figure 16 Schematic diagram of step S203 in the second embodiment, Figure 20 Draw Figure 19 A schematic cross-sectional view of the lead frame 210 along the section line 20-20 in the second embodiment. Figure 16 and Figure 19 、 Figure 20 As can be seen, step S203 includes placing a metal paste MP in the slots S. By setting the amount of metal paste MP, the metal paste MP is directly placed in each slot S, and the volume of the metal paste MP corresponds to the volume of each slot S. Specifically, by setting a certain amount of metal paste MP to be squeezed into each slot S, the cost of preparing the corresponding printing mold is saved.

[0111] Please refer to Figure 21 and Figure 22 ,in Figure 21 Draw Figure 16 Schematic diagram of step S204 in the second embodiment, Figure 22 Draw Figure 21 A schematic cross-sectional view of the lead frame 210 along the section line 22-22 in the second embodiment. Figure 16 and Figure 21 、 Figure 22 As can be seen, step S204 includes heating the metal paste MP to form a solderable portion 230 in each slot S, with the solderable portion 230 covering one side of each lead 211. Specifically, the depth of the slot S is greater than the thickness of each lead 211, and the width of the slot S is slightly wider than the width of one side of each lead 211. Therefore, the solderable portion 230 can completely cover one side of each lead 211.

[0112] Please refer to Figures 23 to 26 , Figure 23 Draw Figure 16 Schematic diagram of step S205 in the second embodiment, Figure 24 Draw Figure 23 A schematic cross-sectional view of the package structure 200 along the section line 24-24 in the second embodiment, Figure 25 Draw Figure 16 A front view of the package structure 200 in the second embodiment, Figure 26 Draw Figure 16 The back side view of the package structure 200 in the second embodiment. Figure 16 and Figures 23 to 26 It can be seen that step S205 includes cutting the cutting line 212 (shown in FIG. Figure 17 ) to form a package structure 200.

[0113] Please refer to Figure 27 and Figure 28 ,in Figure 27 Draw Figure 16 A partial schematic diagram of a packaging structure 200 in the second embodiment, Figure 28 Draw Figure 16 A side view of the package structure 200 in the second embodiment. Figures 25 to 28As can be seen, the package structure 200 includes a lead frame 210, a semiconductor chip, a plastic encapsulation material 220, and a solderable portion 230, wherein the plastic encapsulation material 220 is disposed on the lead frame 210. The lead frame 210 includes a die pad 213 and pins 211, wherein the pins 211 are disposed around the die pad 213. The semiconductor chip is disposed on the die pad 213 of the lead frame 210, and the solderable portion 230 covers the surface of each pin 211.

[0114] Please refer to Figure 29 and Figure 30 ,in Figure 29 Draw Figure 16 A side view of the package structure 200 after soldering in the second embodiment. Figure 30 Draw Figure 29 A partial side view of the package structure 200 after soldering in the second embodiment. Figure 29 and Figure 30 It can be seen that when the package structure 200 is connected to the circuit board through a solder portion SN, since the solderable portion 230 completely covers the surface of each pin 211, the solder portion SN can be set over a wide range, that is, the side of each pin 211 has a wide solderable area, thereby improving the connection strength with the circuit board.

[0115] It must be noted that the thickness of the metal paste MP, the thickness of the weldable portion 230 and the width of the slot S in the second embodiment are only used to illustrate their arrangement relationship and are not the actual thickness and width.

[0116] In addition, the structures and configurations of the remaining components of the second embodiment are the same as those of the first embodiment, and will not be further described here.

[0117] Please refer to Figure 31 , which illustrates a flow chart of a method S300 for forming a package structure according to the third embodiment of the present invention. Figure 31 It can be seen that the method S300 for forming a package structure includes steps S301 , S302 , S303 , S304 , S305 , and S306 .

[0118] Please refer to Figure 32 and Figure 33 ,in Figure 32 Draw Figure 31 Schematic diagram of steps S301, S302, and S303 in the third embodiment, Figure 33 Draw Figure 32 A schematic cross-sectional view of the lead frame 310 along the section line 33-33 in the third embodiment. Figures 31 to 33It can be seen that step S301 includes setting a plastic packaging material 320 on the lead frame 310, step S302 includes forming at least one slot S on a surface of the lead frame 310, and step S303 includes setting a metal paste MP in the slot S, wherein the lead frame 310 includes a plurality of pins 311 and a plurality of cutting lanes 312, the slot S is set on one side of at least one of the pins 311, and the metal paste MP can be set in the slot S through a mold ST.

[0119] Furthermore, in the third embodiment, there are multiple slots S, and the slots S are located on one side of some of the pins 311, and the metal paste MP is selectively set on one side of some of the pins 311, wherein the above-mentioned pins 311 are used for grounding. The number of the above-mentioned grounding pins 311 is four and is respectively located around the lead frame 310, but the number is not limited to this.

[0120] Please refer to Figure 34 and Figure 35 ,in Figure 34 Draw Figure 31 The schematic diagram of step S304 in the third embodiment, Figure 35 Draw Figure 34 A schematic cross-sectional view of the lead frame 310 along the section line 35-35 in the third embodiment. Figure 31 and Figure 34 、 Figure 35 As can be seen, step S304 involves placing a shielding element 340 on the surface of the lead frame 310, with the shielding element 340 on the same side as the slot S. Shielding element 340 is placed during the packaging process to facilitate subsequent assembly. Specifically, shielding element 340 is in physical contact with the metal paste MP. The placement of the metal paste MP controls the connection between some of the leads 311 and the shielding element 340.

[0121] Please refer to Figures 36 to 39 ,in Figure 36 Draw Figure 31 Schematic diagram of steps S305 and S306 in the third embodiment, Figure 37 Draw Figure 36 A schematic cross-sectional view of the package structure 300 along the section line 37-37 in the third embodiment, Figure 38 Draw Figure 31 A front view of the package structure 300 in the third embodiment, Figure 39 Draw Figure 31 The back side view of the package structure 300 in the third embodiment. Figure 31 and Figures 36 to 39 It can be seen that step S305 includes heating the metal paste MP to form a solderable portion 330 in each slot S, and step S306 includes cutting the cutting street 312 (shown in FIG. Figure 32) to form a package structure 300, wherein the solderable portion 330 covers one side of at least one of the leads 311. Further, the solderable portion 330 covers one side of four of the leads 311 respectively.

[0122] Please refer to Figure 40 , which shows Figure 31 A partial schematic diagram of the packaging structure 300 in the third embodiment. Figures 38 to 40 As can be seen, package structure 300 includes a lead frame 310, a semiconductor chip, a plastic encapsulating material 320, a solderable portion 330, and a shielding element 340. Plastic encapsulating material 320 is disposed on lead frame 310, and shielding element 340 is disposed on a surface of lead frame 310. Lead frame 310 includes a die pad 313 and leads 311. The leads 311 are disposed around die pad 313. The semiconductor chip is disposed on die pad 313 of lead frame 310. The solderable portion 330 covers a surface of at least one of the leads 311. Specifically, the solderable portion 330 covers a surface of four of the leads 311.

[0123] Depend on Figure 34 、 Figure 36 and Figure 40 It can be seen that the packaging structure 300 may further include an isolation layer 350, wherein the isolation layer 350 is disposed on one side of at least another one of the pins 311, and the isolation layer 350 may contact one side of at least another one of the pins 311 or have a gap with one side of at least another one of the pins 311. Specifically, the isolation layer 350 may be an element or coating on the inner surface of the shielding element 340, and the isolation layer 350 is selectively disposed on one side of at least another one of the pins 311. In detail, if metal paste MP is already disposed on one side of the pin 311, the isolation layer 350 is not disposed on the side of the above-mentioned pin 311. It must be noted that, except for some pins 311 that are ground wires, other pins 311 cannot be connected, so the isolation layer 350 is disposed on the side of the pin 311 where the metal paste MP is not disposed. In this way, the isolation layer 350 is used to isolate the side of the pin 311 where the metal paste MP is not disposed and the shielding element 340, respectively, to avoid welding short circuits.

[0124] Furthermore, when the distance between the pins 311 where the metal paste MP is not disposed and the shielding element 340 is wide enough, the isolation layer 350 can be selectively disposed on the package structure 300 .

[0125] Specifically, the shielding element 340 may be an electromagnetic interference shielding element, but is not limited thereto.

[0126] It must be noted that the thickness of the metal paste MP, the thickness of the weldable portion 330 , the width of the slot S, the thickness of the shielding element 340 and the thickness of the isolation layer 350 in the third embodiment are only used to illustrate their arrangement relationship and are not actual thicknesses and widths.

[0127] In addition, the structures and configurations of the remaining components of the third embodiment are the same as those of the first embodiment, and will not be further elaborated here.

[0128] Please refer to Figure 41 and Figure 42 ,in Figure 41 A partial schematic diagram of a method for forming a package structure according to a fourth embodiment of the present invention is shown. Figure 42 Draw Figure 41 A schematic cross-sectional view of the lead frame along the section line 42-42 in the fourth embodiment. Figure 41 and Figure 42 It can be seen that the method for forming a package structure (not shown) includes multiple steps, wherein the steps include setting a plastic packaging material 420 on a lead frame (not shown), forming a plurality of grooves (not shown) on a surface of the lead frame, setting a metal paste (not shown) in the grooves, heating the metal paste to form a solderable portion 430 in each groove, and cutting the cutting line (not shown) of the lead frame to form the package structure 400 (marked on Figure 43 ), wherein the lead frame includes a plurality of pins 411 and a plurality of cutting lines, the slots are respectively provided on one side of four of the pins 411, and the solderable portions 430 respectively cover one side of the four of the pins 411. Furthermore, the slots are selectively provided on one side of some of the pins 411, and the method for forming the slots in the fourth embodiment can refer to the second embodiment, wherein the pins 411 are used for grounding.

[0129] Furthermore, the method for forming the package structure may further include a step of disposing a shielding element 440 on a surface of the plastic packaging material 420. Specifically, the shielding element 440 may be disposed after forming the solderable portion 430 with the metal paste and cutting the scribe line of the lead frame, but the present invention is not limited thereto.

[0130] Please refer to Figures 43 to 45 ,in Figure 43 Draw Figure 41 A front view of the packaging structure 400 in the fourth embodiment, Figure 44 Draw Figure 41 A schematic diagram of the back side of the packaging structure 400 in the fourth embodiment, Figure 45 Draw Figure 41 A partial schematic diagram of the packaging structure 400 in the fourth embodiment. Figures 43 to 45As can be seen, the package structure 400 includes a lead frame, a semiconductor chip, a plastic encapsulating material 420, a solderable portion 430, a shielding element 440, and an insulating layer 450. The plastic encapsulating material 420 is disposed on the lead frame, and the shielding element 440 is disposed on a surface of the plastic encapsulating material 420. The lead frame includes a die pad 413 and leads 411, wherein the leads 411 are disposed around the die pad 413. The semiconductor chip is disposed on the die pad 413 of the lead frame. The solderable portion 430 covers the surfaces of four of the leads 411, and the insulating layer 450 is disposed on one side of at least another of the leads 411.

[0131] It must be noted that the difference between the fourth embodiment and the third embodiment is that the shielding element is set on a surface of the plastic packaging material or the surface of the lead frame, and the thickness of the solderable portion 430, the thickness of the shielding element 440 and the thickness of the isolation layer 450 in the fourth embodiment are only used to illustrate their setting relationship and are not actual thicknesses.

[0132] In addition, the structures and configurations of the remaining components of the fourth embodiment are the same as those of the first embodiment and the third embodiment, and will not be further elaborated here.

[0133] Please refer to Figures 46 to 49 ,in Figure 46 FIG. 1 is a partial schematic diagram illustrating a method for forming a package structure 500 according to a fifth embodiment of the present invention. Figure 47 Draw Figure 46 A schematic cross-sectional view of the lead frame along the section line 47-47 in the fifth embodiment, Figure 48 Draw Figure 46 Another partial schematic diagram of the method for forming the package structure 500 in the fifth embodiment, Figure 49 Draw Figure 48 A schematic cross-sectional view of the lead frame along the section line 49-49 in the fifth embodiment. Figures 46 to 49 As can be seen, the method for forming a package structure (not shown) includes multiple steps, wherein the steps include disposing a plastic packaging material 520 on a lead frame (not shown), forming a plurality of grooves (not shown) on a surface of the lead frame, disposing a metal paste MP in the grooves, heating the metal paste MP to form a solderable portion 530 in each groove, and cutting the cutting street 512 of the lead frame to form the package structure 500 (marked on Figure 50 ), wherein the lead frame includes a plurality of pins 511, slots are respectively provided on one side of four of the pins 511, and the solderable portions 530 respectively cover one side of the four of the pins 511. Furthermore, the slots are selectively provided on one side of some of the pins 511, and the method for forming the slots in the fifth embodiment can refer to the second embodiment, wherein the pins 511 are used for grounding.

[0134] The method for forming the package structure further includes a step of disposing a shielding element 540 on a surface of the plastic packaging material 520. Specifically, after slots are formed in the plastic packaging material 520 along the scribe lines 512 using a laser beam L or a cutting tool, the shielding element 540 is disposed on the surface of the plastic packaging material 520. The metal paste MP is then formed into the solderable portion 530. The remaining plastic packaging material 520 along the scribe lines 512 is then removed using the laser beam L or a cutting tool to form the package structure 500, but the present invention is not limited thereto.

[0135] Please refer to Figures 50 to 52 ,in Figure 50 Draw Figure 46 A front view of a packaging structure 500 in the fifth embodiment, Figure 51 Draw Figure 46 A schematic diagram of the back side of the packaging structure 500 in the fifth embodiment, Figure 52 Draw Figure 46 A partial schematic diagram of the packaging structure 500 in the fifth embodiment. Figures 50 to 52 As can be seen, the package structure 500 includes a lead frame, a semiconductor chip, a plastic encapsulating material 520, a solderable portion 530, a shielding element 540, and an insulating layer 550. The plastic encapsulating material 520 is disposed on the lead frame, and the shielding element 540 is disposed on a surface of the plastic encapsulating material 520. The lead frame includes a die pad 513 and leads 511, wherein the leads 511 are disposed around the die pad 513. The semiconductor chip is disposed on the die pad 513 of the lead frame. The solderable portion 530 covers the surfaces of four of the leads 511, and the insulating layer 550 is disposed on one side of at least another of the leads 511.

[0136] In the fifth embodiment, the shielding element 540 is used to cover half the height of the solderable portion 530 , and the height of the isolation layer 550 is the same as that of the shielding element 540 .

[0137] It must be noted that the difference between the fifth embodiment and the fourth embodiment is that the shielding element is used to cover the range of the solderable portion, and the thickness of the metal paste MP, the thickness of the solderable portion 530, the thickness of the shielding element 540 and the thickness of the insulating layer 550 in the fourth embodiment are only used to illustrate their setting relationship, not the actual thickness.

[0138] In addition, the structures and configurations of the remaining components of the fifth embodiment are the same as those of the first embodiment, the third embodiment, and the fourth embodiment, and will not be further elaborated here.

[0139] In summary, by completely encapsulating the pins with solderable portions, copper exposure on the pins is avoided, thereby increasing the solderable area on the sides of the package structure. This improves the connection strength between the package structure and the circuit board, further enhancing the package's board-level reliability and enabling widespread automotive application. Furthermore, shielding elements can be incorporated to facilitate subsequent assembly operations.

[0140] Although the present invention has been disclosed above with reference to the embodiments, they are not intended to limit the present invention. Anyone with ordinary knowledge in the technical field may make slight changes and modifications without departing from the spirit and scope of the present invention. Therefore, the scope of protection of the present invention shall be determined by the appended claims.

Claims

1. A method for forming a packaging structure, characterized in that: The following steps are involved: forming a plurality of slots on a surface of a lead frame, wherein the lead frame includes a plurality of pins, and the plurality of slots are disposed on one side of each of the plurality of pins; Disposing a metal paste in the plurality of slots; heating the metal paste to form a solderable portion in each of the plurality of grooves; as well as cutting a plurality of cutting streets of the lead frame to form a packaging structure; The solderable portion covers the side of each of the plurality of pins.

2. The method for forming a package structure according to claim 1, wherein: It also includes the following steps: A plastic packaging material is disposed on the lead frame.

3. The method for forming a package structure according to claim 1, wherein: The plurality of slots are disposed between each of the plurality of pins and each of the plurality of cutting streets.

4. The method for forming a package structure according to claim 1, wherein: The plurality of grooves are formed on the surface of the lead frame by using a laser beam.

5. The method for forming a package structure according to claim 1, wherein: The plurality of slots are connected to each other.

6. The method for forming a package structure according to claim 1, wherein: There is a gap between every two of the plurality of slots.

7. The method for forming a package structure according to claim 6, wherein: The metal paste is directly disposed in each of the plurality of slots, and the volume of the metal paste corresponds to the volume of each of the plurality of slots.

8. The method for forming a package structure according to claim 1, wherein: The metal paste is further disposed on a surface of a chip base of the lead frame.

9. The method for forming a package structure according to claim 1, wherein: The width of each of the plurality of slots is 0.1 mm to 10 mm.

10. The method for forming a package structure according to claim 1, wherein: The metal paste is disposed in the plurality of grooves through a mold.

11. A method for forming a packaging structure, characterized in that: The following steps are involved: forming at least one slot on a surface of a lead frame, wherein the lead frame includes a plurality of pins, and the at least one slot is disposed on a side of at least one of the plurality of pins; Disposing a metal paste in the at least one slot; heating the metal paste to form a solderable portion in the at least one groove; as well as cutting a plurality of cutting streets of the lead frame to form a packaging structure; The solderable portion covers the side of at least one of the plurality of pins.

12. The method for forming a package structure according to claim 11, wherein: It also includes the following steps: Disposing a plastic packaging material on the lead frame; and A shielding element is disposed on a surface of the plastic packaging material or the surface of the lead frame.

13. A packaging structure, characterized in that: Include: A lead frame comprising: a wafer holder; and A plurality of pins are arranged around the wafer seat; a semiconductor chip disposed on the chip holder of the lead frame; a plastic packaging material disposed on the lead frame; and A solderable portion covers a surface of at least one of the plurality of pins.

14. The packaging structure according to claim 13, wherein: Also includes: A shielding element is disposed on a surface of the plastic packaging material or a surface of the lead frame.

15. The packaging structure according to claim 14, wherein: The shielding element is an electromagnetic wave interference shielding element.

16. The packaging structure according to claim 14, wherein: Also includes: An isolation layer is disposed on one side of at least another one of the plurality of pins.

17. The packaging structure according to claim 13, wherein: The solderable portion is made of a tin alloy.

18. The packaging structure according to claim 13, wherein: The solderable portion covers the surface of each of the plurality of pins.

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