Lead frame

Abstract

The utility model discloses a lead frame, which comprises a first frame and a second frame, the first frame is provided with an abdicating hole, the inner wall of a frame of the abdicating hole is connected with a plurality of pins, and at least parts of the pins protrude downwards relative to the lower surface of the frame; the second frame is provided with a bonding pad, and the peripheral wall of the bonding pad is provided with supporting strips extending outwards. Wherein the second frame is arranged on the lower side of the first frame, the bonding pads are located in projections of the receding holes in the vertical direction, the bonding pads and the pins are arranged at intervals, the supporting strips extend to the lower side of the frame, the horizontal height of the upper surfaces of the bonding pads is smaller than that of the upper surfaces of the pins, and the lower surfaces of the bonding pads are flush with the lower surfaces of the pins. Therefore, the chip can be conveniently installed on the upper surface of the bonding pad and located in the abdicating hole, meanwhile, the height difference between the chip and the pins after the chip is installed can be reduced, the overall thickness of the lead frame after the chip is packaged is further reduced, and miniaturization of chip packaging is facilitated.

Description

Technical Field

[0001] This utility model relates to the field of chip packaging technology, and in particular to a lead frame. Background Technology

[0002] In existing technologies for molding leadframes, pins and pads for chip mounting are typically formed on the frame through processes such as etching and electroplating. Then, epoxy resin or other molding materials are used to mold the leadframe to form the required leadframe. However, in this structure, the pads and pins are usually on the same plane. During chip packaging, the chip needs to be attached to the pads, resulting in a large height difference between the chip and the pins. This leads to an increase in the thickness of the packaged chip, which is not only detrimental to the miniaturization of the chip package but also affects the overall heat dissipation. Utility Model Content

[0003] This invention aims to solve at least one of the technical problems existing in the prior art. To this end, this invention proposes a lead frame that can improve the overall thickness of the lead frame after miniaturizing chip packaging.

[0004] A lead frame according to an embodiment of the present invention includes: a first frame having a first frame unit, the first frame unit having a clearance hole arranged in a vertical direction, a plurality of pins extending toward the interior of the clearance hole being connected to the inner wall of the frame of the clearance hole, all the pins being arranged circumferentially at intervals along the clearance hole, and at least a portion of the pins protruding downward relative to the lower surface of the frame; a second frame having a second frame unit corresponding to the first frame unit, the second frame unit having a pad, and the outer peripheral wall of the pad having an outwardly extending support strip; wherein, the second frame is located below the first frame, the pad is located within the projection in the vertical direction and is arranged at intervals with each of the pins, the support strip extends to the lower side of the frame, the upper surface of the pad is used to mount a chip, and the horizontal height of the upper surface of the pad is lower than the horizontal height of the upper surface of the pin, and the lower surface of the pad is flush with the lower surface of the pin.

[0005] The lead frame according to the embodiment of this utility model has at least the following beneficial effects:

[0006] In the lead frame of this utility model embodiment, by dividing the lead frame into a first frame and a second frame that are independent of each other, and by setting the pins and pads on the first frame and the second frame respectively, it is convenient to process the pins and pads independently. Furthermore, by creating clearance holes on the first frame unit of the first frame and placing the pins on the inner peripheral wall of the clearance holes, and by setting pads on the second frame unit of the second frame and providing outwardly extending support strips on the outer peripheral wall of the pads, the first frame can be directly mounted on top of the second frame during assembly. This allows the pads to be positioned within the vertical projection of the corresponding clearance holes and spaced apart from the pins. The clearance holes allow the pads to be exposed, facilitating chip mounting on the upper surface of the pads and placing the chip within the clearance holes. Since the upper surface of the pads is lower than the upper surface of the pins, the height difference between the chip and the pins after mounting is reduced. This improves the flatness of the lead frame surface after chip packaging, reduces the overall thickness of the lead frame after chip packaging, promotes chip miniaturization, and improves overall heat dissipation after chip packaging.

[0007] According to some embodiments of the present invention, the lower surface of the first frame is etched upward with a first etching groove arranged circumferentially along the clearance hole. The first etching groove is located below the frame. The depth of the first etching groove is less than the thickness of the first frame. The thickness of the pin protruding downward relative to the frame is equal to the depth of the first etching groove, and the upper surface of the pin is flush with the upper surface of the frame.

[0008] According to some embodiments of the present invention, the free end of the pin further has an extension extending close to the center of the clearance hole, and the lower surface of the first frame is etched upward with a second etching groove located below the extension, so that the pin protrudes downward relative to the extension, and the upper surface of the extension is flush with the upper surface of the pin; or the upper surface of the first frame is etched downward with a third etching groove located above the extension, so that the pin protrudes upward relative to the extension, and the lower surface of the extension is flush with the lower surface of the pin.

[0009] According to some embodiments of the present invention, a fourth etching groove is etched on the side surface of the pin that is flush with the extension, and the depth of the fourth etching groove is less than the thickness of the first frame.

[0010] According to some embodiments of the present invention, the pad includes an upper mounting portion and a lower mounting portion. The upper mounting portion is located above the lower mounting portion, and the outer periphery of the upper mounting portion extends outward relative to the lower mounting portion. The support strip is connected to the outer periphery of the upper mounting portion. The upper surface of the upper mounting portion is at a lower level than the upper surface of the pin, and the lower surface of the lower mounting portion is flush with the lower surface of the pin.

[0011] According to some embodiments of the present invention, the lower surface of the second frame is etched with a fifth etching groove along the circumferential direction of the lower mounting portion, such that the upper mounting portion and the support strip are both located above the fifth etching groove, and the thickness of the lower mounting portion is equal to the depth of the fifth etching groove.

[0012] According to some embodiments of the present invention, a plastic encapsulation portion is filled between the first frame and the second frame. The pins are embedded in the plastic encapsulation portion and the upper surface of the pins is flush with the upper surface of the plastic encapsulation portion. The support strip is embedded inside the plastic encapsulation portion. The upper surface of the plastic encapsulation portion has mounting grooves corresponding to each of the solder pads. The upper surface of the solder pads is at least partially located within the projection of the mounting grooves in the vertical direction. The lower surfaces of the pins and the solder pads are both flush with the lower surface of the plastic encapsulation portion.

[0013] According to some embodiments of the present invention, the first frame is provided with a first positioning part located outside the first frame unit, and the second frame is provided with a second positioning part located outside the second frame unit. One of the first positioning part and the second positioning part is provided with a positioning hole, and the other is provided with a positioning post that can be inserted into the positioning hole.

[0014] According to some embodiments of the present invention, the number of the first frame unit and the second frame unit is at least two, two adjacent first frame units are connected to each other through the corresponding border, and two adjacent second frame units are connected through the corresponding support strip.

[0015] According to some embodiments of the present invention, both the first frame and the second frame are made of copper, and both the outer surfaces of the first frame and the second frame are coated.

[0016] Additional aspects and advantages of this invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description

[0017] The above and / or additional aspects and advantages of this utility model will become apparent and readily understood from the description of the embodiments taken in conjunction with the following drawings, in which:

[0018] Figure 1 This is a schematic diagram of the bottom surface of the first frame according to an embodiment of the present utility model;

[0019] Figure 2 This is a schematic diagram of the bottom surface of the second frame according to an embodiment of the present utility model;

[0020] Figure 3 This is a cross-sectional schematic diagram of the first frame unit according to an embodiment of the present utility model;

[0021] Figure 4 This is a cross-sectional schematic diagram of the second frame unit according to an embodiment of the present utility model;

[0022] Figure 5 This is a schematic diagram of the bottom surface of the lead frame according to an embodiment of the present utility model;

[0023] Figure 6 This is a cross-sectional schematic diagram of a lead frame according to an embodiment of the present invention;

[0024] Figure 7 This is a cross-sectional schematic diagram of the lead frame according to another embodiment of the present invention;

[0025] Figure 8 This is a cross-sectional schematic diagram of the lead frame according to another embodiment of the present invention;

[0026] Figure 9 This is a top view of the lead frame after molding, according to an embodiment of the present invention.

[0027] Figure 10 This is a bottom view of the lead frame after molding, according to an embodiment of the present invention.

[0028] Figure label:

[0029] First frame 100, first frame unit 110, clearance hole 120, frame 121, first etching groove 122, pin 130, fourth etching groove 131, extension 140, second etching groove 141;

[0030] Second frame 200, second frame unit 210, pad 220, upper mounting part 221, lower mounting part 222, support bar 230, fifth etching groove 240;

[0031] Plastic sealing part 300, mounting groove 310, protrusion 320;

[0032] Chip 400. Detailed Implementation

[0033] The embodiments of this utility model are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain this utility model, and should not be construed as limiting this utility model.

[0034] In the description of this utility model, it should be understood that the directional descriptions, such as up, down, front, back, left, right, etc., indicate the directional or positional relationship based on the directional or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this utility model.

[0035] In the description of this utility model, "several" means one or more, "multiple" means two or more, "greater than," "less than," and "exceeding" are understood to exclude the stated number, while "above," "below," and "within" are understood to include the stated number. If "first" or "second" is used in the description, it is only for the purpose of distinguishing technical features and should not be construed as indicating or implying relative importance, or implicitly indicating the number of indicated technical features, or implicitly indicating the order of the indicated technical features.

[0036] In the description of this utility model, unless otherwise explicitly defined, terms such as "setting," "installation," and "connection" should be interpreted broadly, and those skilled in the art can reasonably determine the specific meaning of the above terms in this utility model in conjunction with the specific content of the technical solution.

[0037] Reference Figures 1 to 10This utility model provides a lead frame, which includes a first frame 100 and a second frame 200. The first frame 100 has a first frame unit 110, which has a clearance hole 120 arranged in a vertical direction. The inner wall of the frame 121 of the clearance hole 120 is connected to a plurality of pins 130 extending toward the interior of the clearance hole 120. All pins 130 are arranged circumferentially at intervals along the clearance hole 120, and at least part of the pins 130 protrude downward relative to the lower surface of the frame 121 of the clearance hole 120. The second frame 200 has a second frame unit 210 corresponding to the first frame unit 110. The second frame unit 210 is provided with a pad 220, and the outer peripheral wall of the pad 220 is provided with an outwardly extending support strip 230. The second frame 200 is located below the first frame 100. The pad 220 is located within the vertical projection of the corresponding clearance hole 120 and is spaced apart from each pin 130. The support bar 230 extends to the lower side of the frame 121. The upper surface of the pad 220 is used to mount the chip 400, and the horizontal height of the upper surface of the pad 220 is lower than the horizontal height of the upper surface of the pin 130. The lower surface of the pad 220 is flush with the lower surface of the pin 130.

[0038] In the lead frame of this embodiment, by dividing the lead frame into an independent first frame 100 and a second frame 200, and separately disposing of the pins 130 and pads 220 on the first frame 100 and the second frame 200, it is convenient to independently process the pins 130 and pads 220, which is beneficial to improving the production efficiency of the lead frame. Furthermore, by providing clearance holes 120 on the first frame unit 110 of the first frame 100 and placing the pins 130 on the inner peripheral wall of the clearance holes 120, and by providing pads 220 on the second frame unit 210 of the second frame 200 and providing outwardly extending support strips 230 on the outer peripheral wall of the pads 220, during assembly, the first frame 100 can be directly installed above the second frame 200, and the pads 220 are positioned within the vertical projection of the corresponding clearance holes 120 and spaced apart from each pin 130. That is, the clearance holes 120 can accommodate the pads 220. The pad 220 is exposed by making room for the chip 400, allowing it to be easily mounted on the upper surface of the pad 220 and positioned within the clearance hole 120. Since the upper surface of the pad 220 is lower than the upper surface of the pin 130, the height difference between the chip 400 and the pin 130 is reduced, improving the flatness of the lead frame surface after chip 400 packaging, reducing the overall thickness of the lead frame, facilitating miniaturization of the chip 400 package, and improving overall heat dissipation. Furthermore, the lower surface of the pad 220 is flush with the lower surface of the pin 130, improving the flatness of the lower surface of the lead frame, facilitating mounting of the lead frame on the circuit board, and connecting the chip 400 to power via the pin 130 and the lower surface of the pad 220.

[0039] Reference Figures 1 to 10 In some embodiments, the thickness of the pad 220 can be set to the thickness of the pin 130 protruding downward relative to the edge 121 of the clearance hole 120, thereby enabling the pad 220 to be flush with the downward protrusion of the pin 130 and located exactly below the clearance hole 120.

[0040] Reference Figures 1 to 10 In some embodiments, the lower surface of the first frame 100 is etched upward with a first etching groove 122 arranged circumferentially along the relief hole 120. The first etching groove 122 is located below the frame 121. The depth of the first etching groove 122 is less than the thickness of the first frame 100. The thickness of the protrusion of the pin 130 relative to the lower frame 121 of the relief hole 120 is equal to the depth of the first etching groove 122. The upper surface of the pin 130 is flush with the upper surface of the frame 121 of the relief hole 120.

[0041] By adopting the above structure, during processing, the first etching groove 122 can be etched upward along the circumference of the relief hole 120 from the lower surface of the first frame 100, so that the thickness of the edge 121 of the relief hole 120 is less than the thickness of the first frame 100, and the pin 130 protrudes downward relative to the edge 121 of the relief hole 120 at least partially. That is, no etching is performed at the pin 130, the thickness of the pin 130 is equal to the thickness of the first frame 100, and the thickness of the pin 130 protruding downward relative to the edge 121 is equal to the depth of the first etching groove 122. This makes it convenient to process the protruding structure of the pin 130 on the first frame 100. At the same time, since the support bar 230 extends to the edge 121 of the relief hole 120 when assembling the first frame 100 and the second frame 200, by etching the first etching groove 122 below the edge 121 of the relief hole 120, the etched part can provide a space for the support bar 230, which helps to reduce the overall thickness of the lead frame.

[0042] It is understandable that the first etching groove 122 can specifically be a half etching groove.

[0043] Understandably, referring to Figures 1 to 10 In some embodiments, the clearance hole 120 can be a fully etched hole, that is, the clearance hole 120 can be formed by fully etching the first frame 100, or the clearance hole 120 can be formed by half etching from both sides of the first frame 100, or the clearance hole 120 can be formed by mechanical cutting or other processing methods. This utility model does not specifically limit this.

[0044] Reference Figures 1 to 6 In some embodiments, the free end of pin 130 also has an extension 140 extending close to the center of relief hole 120, and a second etching groove 141 located below the extension 140 is etched upward on the lower surface of the first frame 100, such that pin 130 protrudes downward relative to extension 140, and the upper surface of extension 140 is flush with the upper surface of pin 130.

[0045] In the above structure, the free end of pin 130 specifically refers to the end of pin 130 away from the inner peripheral wall of the relief hole 120. That is, one end of pin 130 is connected to the inner peripheral wall of the relief hole 120, and the other end is provided with an extension 140. The extension 140 can shorten the distance between pin 130 and pad 220, thereby shortening the wiring distance between chip 400 and pin 130 when wiring, and facilitating the wiring between chip 400 and pin 130. In addition, by etching a second etching groove 141 below the extension 140, that is, the extension 140 is formed by etching the second etching groove 141 upward from the lower surface of the first frame 100, the upper surface of the extension 140 is flush with the upper surface of pin 130, and pin 130 protrudes downward relative to the extension 140. This not only facilitates the processing of the extension 140, but also increases the surface area of ​​pin 130 in contact with the package during packaging, thereby improving the packaging stability of the lead frame.

[0046] It is understood that in some embodiments, the depth of the second etching groove 141 is equal to the depth of the first etching groove 122. Thus, the extension 140 and the frame 121 of the clearance hole 120 can be processed in the same etching process. That is, the first etching groove 122 and the second etching groove 141 can be etched upward from the lower surface of the first frame 100 at the same time, thereby enabling the frame 121 of the clearance hole 120 and the extension 140 to be processed simultaneously. A pin 130 protruding downward relative to the frame 121 and the extension 140 of the clearance hole 120 is formed between them. This facilitates the processing of the first frame 100 and improves the processing efficiency of the first frame 100.

[0047] Reference Figure 7 In some embodiments, the free end of pin 130 also has an extension 140 extending close to the center of relief hole 120. The upper surface of the first frame 100 is etched downward with a third etch groove located above the extension 140, such that pin 130 protrudes upward relative to extension 140, and the lower surface of extension 140 is flush with the lower surface of pin 130.

[0048] In the above structure, a third etching groove is formed by etching above the extension 140, that is, the extension 140 is formed by etching the second etching groove 141 downward from the upper surface of the first frame 100. This makes the lower surface of the extension 140 flush with the lower surface of the lead 130, while the lead 130 protrudes upward relative to the extension 140. This also facilitates the processing of the extension 140 and increases the surface area of ​​the lead 130 in contact with the package during packaging, thereby improving the packaging stability of the lead frame.

[0049] Reference Figure 8In some embodiments, the upper surface of the pin 130 is flush with the upper surface of the extension 140, and the upper surface of the pin 130 is provided with a fourth etching groove 131, the depth of which is less than the thickness of the first frame 100.

[0050] In the above structure, by etching a fourth etch groove 131 downward on the upper surface of the pin 130, the fourth etch groove 131 can further increase the surface area in contact with the package during packaging, thereby improving the packaging stability of the lead frame.

[0051] It is understood that in some embodiments, when the lower surface of the extension 140 is flush with the lower surface of the pin 130, the fourth etching groove 131 is formed on the lower surface of the pin 130. This can also increase the surface area in contact with the packaging part during packaging, thereby improving the packaging stability of the lead frame. This utility model does not make specific limitations in this regard. It is only necessary that the fourth etching groove 131 is provided on the side surface of the pin 130 that is flush with the extension 140, and the depth of the fourth etching groove 131 is less than the thickness of the first frame 100.

[0052] It is understandable that when the fourth etching groove 131 is opened on the lower surface of the pin 130, the fourth etching groove 131 can be processed synchronously with the first etching groove 122. At this time, the depth of the fourth etching groove 131 is equal to the depth of the first etching groove 122, which facilitates the processing of the first frame 100 and helps to improve the processing efficiency of the first frame 100.

[0053] Reference Figures 1 to 10 In some embodiments, the pad 220 includes an upper mounting portion 221 and a lower mounting portion 222. The upper mounting portion 221 is located above the lower mounting portion 222, and the outer periphery of the upper mounting portion 221 extends outward relative to the lower mounting portion 222. A support strip 230 is connected to the outer periphery of the upper mounting portion 221. The upper surface of the upper mounting portion 221 is at a lower level than the upper surface of the pin 130, and the lower surface of the lower mounting portion 222 is flush with the lower surface of the pin 130.

[0054] In the above structure, by configuring the pad 220 as an upper mounting portion 221 and a lower mounting portion 222, the upper mounting portion 221 can be used to mount the chip 400, and the lower mounting portion 222 can be used to contact and connect to the circuit board. The outer periphery of the upper mounting portion 221 extends outward relative to the lower mounting portion 222, thereby increasing the surface area of ​​the pad 220, which in turn increases the contact area between the pad 220 and the molding compound 300 during leadframe packaging, thus improving the stability of the leadframe package. Furthermore, by setting the support bar 230 on the outer periphery of the upper mounting portion 221, when the first frame 100 is positioned above the second frame 200, the support bar 230 extends to the lower surface of the frame 121 of the clearance hole 120, and the horizontal height of the lower surface of the support bar 230 is higher than the horizontal height of the lower surface of the lead 130. Thus, when the first frame 100 and the second frame 200 are encapsulated, the support bar 230 can be completely embedded inside the encapsulation portion 300, thereby greatly improving the structural stability of the lead frame.

[0055] Reference Figures 1 to 10 In some embodiments, the lower surface of the second frame 200 is etched with a fifth etching groove 240 along the circumferential direction of the lower mounting portion 222, such that the upper mounting portion 221 and the support strip 230 are both located above the fifth etching groove 240, and the thickness of the lower mounting portion 222 is equal to the depth of the fifth etching groove 240.

[0056] In the above structure, the pads 220 and the support bars 230 of the second frame 200 are formed by etching upward from the lower surface of the second frame 200. It is only necessary to etch the fifth etching groove 240 upward along the circumference of the lower mounting portion 222, so that the lower mounting portion 222 protrudes downward relative to the upper mounting portion 221, and the upper mounting portion 221 and the support bars 230 extend outward relative to the lower mounting portion 222. This facilitates processing and helps to improve the processing efficiency of the second frame 200.

[0057] Understandably, referring to Figures 1 to 10 The portion of the outer periphery of the pad 220 located between two adjacent support bars 230 is a cavity structure. This structure can be a fully etched structure, that is, formed by fully etching the second frame 200, or it can be formed by half etching from both sides of the second frame 200, or it can be formed by mechanical cutting or other processes. This utility model does not make any specific limitations on this.

[0058] Reference Figures 1 to 10In some embodiments, a molding compound 300 is filled between the first frame 100 and the second frame 200. The pins 130 are embedded in the molding compound 300 and the upper surface of the pins 130 is flush with the upper surface of the molding compound 300. The support strip 230 is embedded inside the molding compound 300. The upper surface of the molding compound 300 has mounting grooves 310 that correspond one-to-one with each pad 220. The upper surface of the pad 220 is at least partially located within the projection of the mounting groove 310 in the vertical direction. The lower surfaces of the pins 130 and the pads 220 are flush with the lower surface of the molding compound 300.

[0059] In the above structure, the molding compound 300 connects the first frame 100 and the second frame 200 into a stable lead frame. After the lead frame is cut into multiple independent units between two adjacent first molding units, the molding compound 300 can electrically isolate the pins 130 and the pads 220. By forming a mounting groove 310 on the upper surface of the molding compound 300, the chip 400 can be easily mounted on the pads 220 at the bottom of the mounting groove 310, so that the chip 400 is located within the mounting groove 310. This reduces the overall thickness of the lead frame and facilitates the miniaturization of the chip 400 package.

[0060] Understandably, referring to Figures 1 to 10 In some embodiments, the pad 220 includes an upper mounting portion 221 and a lower mounting portion 222. The upper mounting portion 221 is located above the lower mounting portion 222, and the outer periphery of the upper mounting portion 221 extends outward relative to the lower mounting portion 222. In this case, the encapsulation portion 300 filling the space between the first frame 100 and the second frame 200 can wrap the peripheral portion of the upper mounting portion 221 that extends outward relative to the lower mounting portion 222, forming an upper and lower encapsulation structure. This can further increase the bonding area between the encapsulation portion 300 and the pad 200, which is beneficial to further improve the bonding strength between the encapsulation portion 300 and the pad 200, thereby improving the structural strength of the lead frame.

[0061] It is understood that in some embodiments, the molding portion 300 also includes a protrusion 320 located on the upper surface of the first frame 100 and circumferentially distributed along the edge 121. The annular protrusion 320 can form a cup cavity structure and protect and dissipate heat for the chip 400, preventing the chip 400 from being damaged due to overheating and avoiding damage to the chip 400 from the external environment.

[0062] Reference Figures 1 to 10In some embodiments, the first frame 100 is provided with a first positioning part (not shown in the figure) located outside the first frame unit 110, and the second frame 200 is provided with a second positioning part (not shown in the figure) located outside the second frame unit 210. One of the first positioning part and the second positioning part is provided with a positioning hole, and the other is provided with a positioning post that can be inserted into the positioning hole.

[0063] In the above structure, the design of the positioning post and positioning hole enables the positioning and assembly of the first frame 100 and the second frame 200, which is beneficial to improving the processing efficiency of the lead frame.

[0064] It is understood that the positioning hole can be a semi-etched hole or a fully etched hole, and this utility model does not specifically limit it.

[0065] Reference Figures 1 to 10 In some embodiments, there are four first frame units 110 and four second frame units 210. Two adjacent first frame units 110 are connected to each other through the frame 121 of the corresponding clearance hole 120, and two adjacent second frame units 210 are connected through the corresponding support strip 230.

[0066] By adopting the above structure, multiple lead frame units can be simultaneously processed on the lead frame. In use, the lead frame can be cut into multiple lead frame units by cutting from the border 121 between two adjacent first frame units 110. Each lead frame unit can install a chip 400, thereby greatly improving the production efficiency of the lead frame.

[0067] In some embodiments, the first frame 100 and the second frame 200 are both made of copper, and the outer surfaces of the first frame 100 and the second frame 200 are both coated.

[0068] In the above structure, the plating layer can protect the first frame 100 and the second frame 200, preventing the copper components from oxidizing or deforming under pressure, which would affect the electrical performance of the lead frame. In addition, the plating layer can also improve the solderability of the pads 220 and pins 130 on the lead frame, facilitating the stable installation of the chip 400 and the stable connection between the lead frame and the circuit board.

[0069] It is understood that the coating may be a nickel-palladium-gold coating, a silver coating, or a nickel-silver coating, or the coating may adopt other structures, and this utility model does not make specific limitations in this regard.

[0070] The embodiments of the present utility model have been described in detail above with reference to the accompanying drawings. However, the present utility model is not limited to the above embodiments. Within the scope of knowledge possessed by those skilled in the art, various changes can be made without departing from the spirit of the present utility model.

Claims

1. A lead frame, characterized in that, include: A first frame (100) has a first frame unit (110) with a clearance hole (120) arranged in the vertical direction. The inner wall of the frame (121) of the clearance hole (120) is connected to a plurality of pins (130) extending toward the interior of the clearance hole (120). All the pins (130) are arranged circumferentially at intervals along the clearance hole (120), and the pins (130) at least partially protrude downward relative to the lower surface of the frame (121). The second frame (200) has a second frame unit (210) corresponding to the first frame unit (110). The second frame unit (210) is provided with a pad (220), and the outer peripheral wall of the pad (220) is provided with an outwardly extending support strip (230). The second frame (200) is located below the first frame (100), the pad (220) is located in the projection in the vertical direction and is spaced apart from each of the pins (130), the support strip (230) extends to the lower side of the frame (121), the upper surface of the pad (220) is used to mount the chip (400), and the horizontal height of the upper surface of the pad (220) is lower than the horizontal height of the upper surface of the pin (130), and the lower surface of the pad (220) is flush with the lower surface of the pin (130).

2. The lead frame according to claim 1, characterized in that, The lower surface of the first frame (100) is etched upward with a first etching groove (122) arranged circumferentially along the clearance hole (120). The first etching groove (122) is located below the frame (121). The depth of the first etching groove (122) is less than the thickness of the first frame (100). The thickness of the pin (130) protruding downward relative to the frame (121) is equal to the depth of the first etching groove (122). The upper surface of the pin (130) is flush with the upper surface of the frame (121).

3. The lead frame according to claim 2, characterized in that, The free end of the pin (130) also has an extension (140) extending close to the center of the relief hole (120). The lower surface of the first frame (100) is etched upward with a second etching groove (141) located below the extension (140), such that the pin (130) protrudes downward relative to the extension (140), and the upper surface of the extension (140) is flush with the upper surface of the pin (130). Alternatively, the upper surface of the first frame (100) may be etched downwards with a third etching groove located above the extension (140), such that the pin (130) protrudes upwards relative to the extension (140), and the lower surface of the extension (140) is flush with the lower surface of the pin (130).

4. The lead frame according to claim 3, characterized in that, A fourth etching groove (131) is etched on the side surface of the pin (130) that is flush with the extension (140), and the depth of the fourth etching groove (131) is less than the thickness of the first frame (100).

5. The lead frame according to claim 1, characterized in that, The pad (220) includes an upper mounting portion (221) and a lower mounting portion (222). The upper mounting portion (221) is located above the lower mounting portion (222), and the outer periphery of the upper mounting portion (221) extends outward relative to the lower mounting portion (222). The support strip (230) is connected to the outer periphery of the upper mounting portion (221). The upper surface of the upper mounting part (221) is at a lower level than the upper surface of the pin (130), and the lower surface of the lower mounting part (222) is flush with the lower surface of the pin (130).

6. The lead frame according to claim 5, characterized in that, The lower surface of the second frame (200) is etched with a fifth etching groove (240) along the circumferential direction of the lower mounting portion (222), such that the upper mounting portion (221) and the support strip (230) are both located above the fifth etching groove (240), and the thickness of the lower mounting portion (222) is equal to the depth of the fifth etching groove (240).

7. The lead frame according to any one of claims 1 to 6, characterized in that, A molding compound (300) is filled between the first frame (100) and the second frame (200). The pin (130) is embedded in the molding compound (300) and the upper surface of the pin (130) is flush with the upper surface of the molding compound (300). The support strip (230) is embedded inside the molding compound (300). The upper surface of the molding compound (300) has mounting grooves (310) that correspond one-to-one with each of the pads (220). The upper surface of the pads (220) is at least partially located within the projection of the mounting grooves (310) in the vertical direction. The lower surfaces of the pin (130) and the pads (220) are flush with the lower surface of the molding compound (300).

8. The lead frame according to any one of claims 1 to 6, characterized in that, The first frame (100) is provided with a first positioning part located outside the first frame unit (110), and the second frame (200) is provided with a second positioning part located outside the second frame unit (210). One of the first positioning part and the second positioning part is provided with a positioning hole, and the other is provided with a positioning post that can be inserted into the positioning hole.

9. The lead frame according to any one of claims 1 to 6, characterized in that, The number of the first frame unit (110) and the second frame unit (210) is at least two. Two adjacent first frame units (110) are connected to each other through the corresponding frame (121), and two adjacent second frame units (210) are connected to each other through the corresponding support strip (230).

10. The lead frame according to any one of claims 1 to 6, characterized in that, Both the first frame (100) and the second frame (200) are made of copper, and both the outer surfaces of the first frame (100) and the second frame (200) are coated.

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