CN218939664U - Lead frame and packaging structure - Google Patents

Abstract

The disclosure provides a lead frame and a packaging structure, and relates to the technical field of semiconductors. The lead frame comprises a base island and pins, wherein the base island comprises a first base island and a second base island with different cross section sizes, the first base island is arranged on the second base island, and one side, far away from the second base island, of the first base island is used for mounting an electronic device; the pins are arranged on the periphery of the base island. By arranging the first base island and the second base island, steps are formed below the first base island, so that the mobility and the filling property of the adhesive layer are improved, and the binding force between the base island and an electronic device is improved.

Description

Lead frame and packaging structure

Technical Field

The utility model relates to the technical field of semiconductors, in particular to a lead frame and a packaging structure.

Background

In the prior art, most of lead frame base islands are designed in such a way that a single base island bears a single chip or a plurality of base islands bear a plurality of chips, and silver paste or adhesive film materials are used for fixing the chips on the base islands in the process of mounting the chips. Along with the increase of the contact area between the base island and the chip, cavities, bubbles, water vapor and the like are easy to appear on the adhesive film layer, the bubbles and the water vapor are wrapped between the chip and the base island and cannot be discharged, the expansion of the cavities, the bubbles and the water vapor can be further aggravated in the reliability test process, and then the delamination of the bottom of the chip and the adhesive film layer and the delamination of the adhesive film layer and the base island are further caused, and even the popcorn phenomenon appears in severe cases, so that the product is invalid.

Disclosure of Invention

The utility model aims to provide a lead frame and a packaging structure, which can improve the bonding force between a base island and an electronic device and improve the reliability of products.

Embodiments of the present utility model are implemented as follows:

in a first aspect, the present utility model provides a lead frame comprising:

the base island comprises a first base island and a second base island with different cross section sizes, the first base island is arranged on the second base island, and one side, far away from the second base island, of the first base island is used for mounting an electronic device;

and the pins are arranged on the periphery of the base island and are used for being electrically connected with the electronic device.

In an optional embodiment, the device further comprises a support frame, wherein the support frame is arranged on the periphery of the base island, and pins are arranged on the support frame;

and a groove is formed between the support frame and the base island, and the groove is internally used for filling the adhesive layer.

In an alternative embodiment, the second island is connected to a middle portion of the first island.

In an alternative embodiment, the number of the second islands includes a plurality, and the plurality of the second islands are arranged at intervals and are respectively connected with the first islands.

In an alternative embodiment, the support frame is provided with a groove, and the groove is communicated with the groove.

In an alternative embodiment, a surface of a side of the first island remote from the second island is flush with or below a surface of the support shelf.

In an alternative embodiment, a surface of a side of the first base island away from the second base island is flush with a bottom surface of the groove on the support frame.

In an alternative embodiment, the projected area of the second island on the first island is smaller than the surface area of the first island on the side close to the second island.

In a second aspect, the present utility model provides a package structure comprising an electronic device and a leadframe according to any one of the preceding embodiments, the electronic device being provided on the first island.

In an alternative embodiment, a trench is formed at the periphery of the base island; and the two ends of the electronic device extend out of the first base island, the groove is filled with a glue layer, and the glue layer is connected with the electronic device.

In an alternative embodiment, the support frame is provided with a groove, and the groove is communicated with the groove; the electronic device is arranged in the groove.

The embodiment of the utility model has the beneficial effects that:

the lead frame comprises a base island and pins, wherein the upper part of the base island is used for mounting an electronic device. As the first base island and the second base island are arranged in a laminated mode, a step-shaped structure is formed below the first base island, the contact area between the base island and the adhesive layer can be increased, the filling property of the adhesive layer is improved, the bonding force between the base island and an electronic device is improved, and the reliability of a packaged product is improved.

The packaging structure comprises the lead frame, and the electronic device is attached to the first base island, so that the bonding force between the base island and the electronic device is improved, and the reliability of a packaged product is improved.

Drawings

In order to more clearly illustrate the technical solutions of the embodiments of the present utility model, the drawings that are needed in the embodiments will be briefly described below, it being understood that the following drawings only illustrate some embodiments of the present utility model and therefore should not be considered as limiting the scope, and other related drawings may be obtained according to these drawings without inventive effort for a person skilled in the art.

Fig. 1 is a schematic diagram of a first structure of a lead frame according to an embodiment of the present utility model;

fig. 2 is a schematic top view of a first embodiment of a leadframe according to the present utility model;

fig. 3 is a schematic top view of a second type of a leadframe according to an embodiment of the present utility model;

fig. 4 is a schematic structural diagram of a package structure according to an embodiment of the present utility model;

fig. 5 and fig. 6 are schematic views illustrating a process of a package structure according to an embodiment of the utility model.

Icon: a 100-lead frame; 101-a backside copper layer; 110-islands; 111-a first island; 113-a second island; 120-supporting frames; 130-pins; 141-grooves; 143-grooves; 151-ground pads; 153-ground pin; 200-packaging structure; 210-chip; 220-an adhesive layer; 230-plastic package body.

Detailed Description

For the purpose of making the objects, technical solutions and advantages of the embodiments of the present utility model more apparent, the technical solutions of the embodiments of the present utility model will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present utility model, and it is apparent that the described embodiments are some embodiments of the present utility model, but not all embodiments of the present utility model. The components of the embodiments of the present utility model generally described and illustrated in the figures herein may be arranged and designed in a wide variety of different configurations.

Thus, the following detailed description of the embodiments of the utility model, as presented in the figures, is not intended to limit the scope of the utility model, as claimed, but is merely representative of selected embodiments of the utility model. All other embodiments, which can be made by those skilled in the art based on the embodiments of the utility model without making any inventive effort, are intended to be within the scope of the utility model.

It should be noted that: like reference numerals and letters denote like items in the following figures, and thus once an item is defined in one figure, no further definition or explanation thereof is necessary in the following figures.

In the description of the present utility model, it should be noted that, directions or positional relationships indicated by terms such as "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc., are directions or positional relationships based on those shown in the drawings, or are directions or positional relationships conventionally put in use of the inventive product, are merely for convenience of describing the present utility model and simplifying the description, and are not indicative or implying that the apparatus or element to be referred to must have a specific direction, be constructed and operated in a specific direction, and thus should not be construed as limiting the present utility model. Furthermore, the terms "first," "second," "third," and the like are used merely to distinguish between descriptions and should not be construed as indicating or implying relative importance.

Furthermore, the terms "horizontal," "vertical," and the like do not denote a requirement that the component be absolutely horizontal or overhang, but rather may be slightly inclined. As "horizontal" merely means that its direction is more horizontal than "vertical", and does not mean that the structure must be perfectly horizontal, but may be slightly inclined.

In the description of the present utility model, it should also be noted that, unless explicitly specified and limited otherwise, the terms "disposed," "mounted," "connected," and "connected" are to be construed broadly, and may be, for example, fixedly connected, detachably connected, or integrally connected; can be mechanically or electrically connected; can be directly connected or indirectly connected through an intermediate medium, and can be communication between two elements. The specific meaning of the above terms in the present utility model will be understood in specific cases by those of ordinary skill in the art.

Referring to fig. 1 to 4, the present embodiment provides a lead frame 100, which includes a base island 110, pins 130 and a supporting frame 120, wherein the base island 110 includes a first base island 111 and a second base island 113 with different cross-sectional dimensions, the first base island 111 is disposed on the second base island 113, and one side of the first base island 111 far from the second base island 113 is used for mounting electronic devices; pins 130 are disposed on the periphery of the base island 110 for electrical connection with the electronic device. By arranging the first base island 111 and the second base island 113, steps are formed below the first base island 111, which is beneficial to improving the fluidity and filling property of the glue layer 220, so that the binding force between the base island 110 and an electronic device is improved, and the reliability of a packaged product is improved.

The supporting frame 120 is disposed at the periphery of the base island 110 and between the base island 110 and the leads 130. The periphery of the base island 110 forms a trench 141. The trenches 141 are filled with glue layer 220. Optionally, the supporting frame 120 is connected to a portion of the pins 130, so as to improve the strength of the pins 130. A groove 141 is formed between the support frame 120 and the base island 110.

The electronic device in this embodiment may be a chip 210, a capacitor, a resistor, or the like, and is not particularly limited herein.

The second base island 113 is connected to the middle of the first base island 111, so that the stress of the first base island 111 is more uniform. The cross-sectional dimension of the second island 113 is smaller than the cross-sectional dimension of the first island 111. It will be appreciated that the projected area of the second island 113 on the first island 111 is smaller than the surface area of the first island 111 on the side closer to the second island 113. In this way, the step shape is formed under the first base island 111, which is favorable for improving the mobility and filling property of the glue layer 220 in the groove 141, and further increasing the binding force between the base island 110 and the glue layer 220 and between the base island 110 and the electronic device.

Referring to fig. 1 and 2, in this embodiment, the number of second islands 113 is one and is connected to the middle of the first islands 111. Of course, the number of the first islands 111 may also include a plurality of first islands 111 spaced apart from each other and connected to the second islands 113. The sum of the cross-sectional areas of the plurality of second islands 113 is smaller than the cross-sectional area of the first island 111. In connection with fig. 3, the situation of two second islands 113 is shown in fig. 3. When the plurality of second islands 113 are provided, the plurality of second islands 113 may be identical in size, shape, height, or the like, or may be different. The number of steps formed at the bottom of the first island 111 may be one or more, and is not particularly limited herein. The arrangement of the plurality of second islands 113 can increase the capillary action on the gel, and further improve the filling property and fluidity of the gel in the grooves 141. The number of second islands 113 may also be 3, 4, 5, 6 or more.

Optionally, the support 120 is provided with a groove 143, and the groove 143 is communicated with the groove 141. In this embodiment, a groove 143 is formed on a side of the support frame 120 near the base island 110. The pins 130 are located on a side of the support frame 120 away from the pins 130. By providing the supporting frame 120, the overall structural strength of the lead frame 100 can be improved, and the warpage of the lead frame 100 in the packaging process can be alleviated.

It can be appreciated that by providing the recess 143 on the supporting frame 120, the electronic device can be mounted in the recess 143, which serves to reduce the mounting height, and is beneficial to reducing the height of the entire package structure 200. Secondly, by forming the groove 143, the function of storing excessive glue overflow can be achieved, and the glue is prevented from overflowing and climbing to the upper surface of the electronic device. The upper surface of the electronic device may be understood as a side surface of the electronic device remote from the first base island 111.

Optionally, referring to fig. 5, the depth B of the groove 143 is one third to one half of the thickness a of the chip 210, which can not only play a role in preventing glue overflow, but also reduce the mounting height. It should be noted that, the electronic device is attached to the first base island 111, and two ends of the electronic device extend out of the first base island 111, and the extending portion may be located on the surface of the supporting frame 120 or in the groove 143. In other words, a surface of a side of the first base island 111 remote from the second base island 113 may be flush with a surface of the support frame 120 or lower than a surface of the support frame 120. A surface of a side of the first base island 111 remote from the second base island 113 may be flush with a surface of the support bracket 120. Optionally, a surface of a side of the first base island 111 away from the second base island 113 is lower than a surface of the supporting frame 120, and a surface of the first base island 111 away from the second base island 113 is flush with a bottom surface of the groove 143 on the supporting frame 120, so that the packaging height can be further reduced.

Optionally, the four corners of the supporting frame 120 are respectively provided with a grounding pin 153 for wire-bonding connection with a grounding point of the chip 210, so as to realize grounding of the chip 210. And, it is advantageous to implement electromagnetic shielding of the chip 210 in a subsequent process.

In this embodiment, the four corners of the supporting frame 120 are respectively provided with a grounding pad 151, the grounding pin 153 is connected with the grounding pad 151, and the width of the grounding pin 153 is smaller than the width of the grounding pad 151. Optionally, the width of the ground pin 153 is one third to one half of the width of the ground pad 151. And, the grounding pin 153 is partially arranged on the cutting path, so that the cutting efficiency is improved, the abrasion to the cutting tool is reduced, and the service life of the tool is prolonged in the process of separating the subsequent cutting into single products.

The embodiment of the present utility model further provides a package structure 200, including an electronic device and a lead frame 100 according to any of the foregoing embodiments, where the electronic device is disposed on the first base island 111. The two ends of the electronic device extend out of the first base island 111, the grooves 141 are filled with glue layers 220, and the glue layers 220 are respectively connected with the electronic device and the base island 110.

The supporting frame 120 is provided with a groove 143, and the groove 143 is communicated with the groove 141; the electronics are disposed within the recess 143. Alternatively, the electronic device employs a chip 210, and the chip 210 is wire-bonded to the pins 130. The lead frame 100 is provided with a plastic package 230 for encapsulating the lead frame 100 and the chip 210, and protecting the lead frame 100 and the chip 210.

Referring to fig. 5 and fig. 6, a manufacturing method of the package structure 200 according to the embodiment of the present utility model is as follows:

a copper material is provided, and the island 110 region and the pattern of the leads 130 are etched by an etching process to form the structure of the support frame 120. Wherein a portion between the base island 110 and the support frame 120 is etched away to form the trench 141, and simultaneously the base island 110 region is etched to form the first base island 111 and the second base island 113. Optionally, during the etching process, the supporting frame 120 is reserved on the copper material, and the groove 143 is etched on the supporting frame 120.

After the etching is completed, the back copper layer 101 remains. The tin plating is again performed on the pins 130 in order to enhance the soldering force of the pins 130. The fabrication of the lead frame 100 is completed.

A chip 210 is mounted on the lead frame 100. Optionally, silver paste and glue layer 220 are coated on first island 111, and glue layer 220 is filled up with trench 141. The chip 210 is fixed on the first base island 111 in a sticking way, and due to the arrangement of the first base island 111 and the second base island 113, a step is formed below the first base island 111, so that the mobility and the filling property of the adhesive layer 220 are improved, and the bonding force of the chip 210 and the base island 110 is improved. Alternatively, the chip 210 may be located in the groove 143 of the supporting frame 120 to reduce the packaging height, and at the same time reduce the climbing height of the bottom gel of the ultra-thin chip 210, and prevent the gel from climbing to the surface of the chip 210.

And wire bonding, the chip 210 is connected with the pins 130 in a wire bonding way. Wherein the functional pads on the chip 210 are wired to the functional pins 130 of the leadframe 100. The ground point on the chip 210 is wired to the ground pin 153 of the leadframe 100 to achieve the ground of the chip 210.

And (3) plastic packaging, namely performing a plastic packaging process, and protecting the welded chip 210 and the wire bonding structure by using a plastic packaging body 230.

Etching is performed again, and the etching process is performed again, so that the back copper layer 101 remaining in the lead frame 100 is etched away by chemical etching, the leads 130 are leaked, and the plurality of leads 130 are separated from each other.

Finally, the package structure 200 of the lead frame 100 is cut into individual products through a cutting process.

It should be noted that, after the manufacturing of the lead frame 100 is completed, the copper layer on the back surface of the lead frame 100 is reserved, so that in the subsequent packaging process, the reserved back surface copper layer 101 can play a role in supporting and improving the structural strength, which is beneficial to reducing the warpage phenomenon in the packaging process and improving the packaging quality. After the encapsulation is completed, the back copper layer 101 is etched away to expose the pins 130, so that the pins 130 are independent.

In summary, the lead frame 100 and the package structure 200 provided in the embodiment of the utility model have the following beneficial effects:

the leadframe 100 includes a base island 110 and a support frame 120, an electronic device is mounted over the base island 110, and a trench 141 is provided between the base island 110 and the support frame 120, which is filled with a glue layer 220. Because the base island 110 is formed by laminating the first base island 111 and the second base island 113, a step structure is formed below the first base island 111, so that the contact area between the base island 110 and the adhesive layer 220 can be increased, the filling property of the adhesive layer 220 in the groove 141 is improved, the bonding force between the base island 110 and an electronic device is improved, and the reliability of a packaged product is improved.

The package structure 200 includes the above-mentioned lead frame 100, and the electronic device is attached to the first base island 111, which is beneficial to improving the bonding force between the base island 110 and the electronic device and improving the reliability of the packaged product.

The above description is only of the preferred embodiments of the present utility model and is not intended to limit the present utility model, but various modifications and variations can be made to the present utility model by those skilled in the art. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present utility model should be included in the protection scope of the present utility model.

Claims (10)

1. A lead frame, comprising:

the base island comprises a first base island and a second base island with different cross section sizes, the first base island is arranged on the second base island, and one side, far away from the second base island, of the first base island is used for mounting an electronic device;

and the pins are arranged on the periphery of the base island and are used for being electrically connected with the electronic device.

2. The leadframe of claim 1, wherein the second island is connected to a middle portion of the first island.

3. The leadframe of claim 1, wherein the number of second islands includes a plurality, the plurality of second islands being spaced apart and connected to the first islands, respectively.

4. The leadframe of claim 1, further comprising a support frame disposed between the base island and the leads, the support frame and the base island forming a trench therebetween, the trench being filled with a glue layer.

5. The leadframe of claim 4 wherein the support frame is notched, the notch being in communication with the channel.

6. The leadframe of claim 5, wherein a surface of a side of the first island remote from the second island is flush with or below a surface of the support frame.

7. The leadframe of claim 6, wherein a surface of the first island distal from the second island is flush with a bottom of the recess in the support frame.

8. The leadframe of claim 1, wherein a projected area of the second island on the first island is smaller than a surface area of a side of the first island adjacent to the second island.

9. A package structure comprising an electronic device and the lead frame according to any one of claims 1 to 8, wherein the electronic device is provided on the first island.

10. The package structure of claim 9, wherein a periphery of the base island forms a trench; and the two ends of the electronic device extend out of the first base island, the groove is filled with a glue layer, and the glue layer is connected with the electronic device.

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