Packaging lead structure

Abstract

The utility model belongs to the field of electronic packaging, and particularly relates to a packaging lead structure, which comprises a base island and at least one pin opposite to the base island, the packaging lead structure comprises a bottom surface, and the height from the base island to the bottom surface is lower than the height from the pin to the bottom surface. The packaging structure has the effect of avoiding short circuit in the packaging structure.

Description

Technical Field

[0001] The present application relates to the field of electronic packaging, and in particular to a packaging lead structure. Background Art

[0002] With the miniaturization and integration of electrical components, the main functions of small circuits are integrated into the chip, and then the electrodes of the chip are brought out through pins to cooperate with other structures. The main components of this small functional unit include chip, base island, pins, etc. In the above structure, the base island serves as the carrier platform of the chip, providing a stable physical and electrical connection; the pins are the path for the transmission of electrical signals. The small packaging unit is widely used in electronic fields such as Hall sensors, field effect transistors, power control modules and charger management modules due to its small size and stable performance.

[0003] In a common production method, the pins and the base island are first fixed on the packaging substrate, and then conductive glue is applied to the surface of the base island, and the chip is attached to the surface of the base island. The physical and electrical connection between the base island and the chip is achieved through the conductive glue. Finally, the surface of all components is poured with packaging glue to form a packaging protective layer.

[0004] However, in the existing chip packaging structure, the conductive glue may overflow during the application process, especially in the area adjacent to the base island and the pin. This phenomenon will cause the conductive glue to short-circuit between the base island and the pin, thereby causing the package unit to short-circuit and fail, affecting its normal operation and reducing the performance and reliability of the product. Therefore, there is an urgent need for a package lead structure that can avoid short-circuiting between the base island and the pin. Utility Model Content

[0005] In order to solve the above problem and avoid short circuit between the pin and the base island caused by overflowing conductive glue, the present application provides a package lead structure.

[0006] A package lead structure provided in this application adopts the following technical solution:

[0007] A package lead structure comprises a base island and at least one pin facing the base island. The package lead structure comprises a bottom surface. The height of the base island from the bottom surface is lower than the height of the pin from the bottom surface.

[0008] By adopting the above technical solution, when the packaging glue overflows from the surface of the base island toward the pin, since the height of the base island from the bottom surface is lower than the height of the pin from the bottom surface, it is equivalent to the base island and the pin being staggered in the thickness direction of the package lead structure. When the conductive glue overflows, it will flow down from the side of the base island under the action of gravity, making it more difficult for the conductive glue to contact the pin, thereby preventing a short circuit between the conductive glue and the pin. This height difference setting forms a certain electrical isolation space between the base island and the pin, thereby improving the overall electrical performance and reliability of the package.

[0009] Optionally, the lower surface of the pin is flush with the upper surface of the base island or the lower surface of the pin is spaced apart from the upper surface of the base island.

[0010] Optionally, the upper surface of the base island is 0.127 mm lower than the upper surface of the pin.

[0011] By adopting the above technical solution, the height difference between the base island and the pin can be adapted to most current pin models, so that the gap between the pin and the base island is large enough, thereby ensuring the yield rate of packaging production.

[0012] Optionally, the thickness of the pin is 0.1 mm.

[0013] By adopting the above technical solution, the lower surface of the pin is lower than the upper surface of the base island, and the overflowed conductive glue directly passes under the pin. Even if the orthographic projections of the pin and the base island on the horizontal plane interfere with each other, no short circuit will occur, making the arrangement of the packaging structure in the horizontal direction more compact, which is conducive to the integration of the electrical system.

[0014] Optionally, a clearance groove is provided on a side of the pin close to the base island.

[0015] Optionally, the orthographic projection of the clearance groove on the bottom surface is a triangle.

[0016] Optionally, the orthographic projection of the clearance groove on the bottom surface is an arcuate shape.

[0017] Optionally, the depth of the clearance groove is 0.05 mm.

[0018] By adopting the above technical solution, the distance between the pin and the conductive adhesive is further increased, further reducing the risk of short circuit.

[0019] Optionally, a chip is disposed on the upper surface of the base island, and the chip is electrically connected to the base island through the conductive adhesive.

[0020] By adopting the above technical solution, when the chip is pressed down to connect with the base island, the conductive glue overflows to the surroundings, matching the relative position relationship between the base island and the pins, thereby avoiding short circuit.

[0021] Optionally, the orthographic projection of the chip on the upper surface of the base island is a rectangle of 1.6 mm*0.85 mm; and the upper surface of the base island is a rectangle of 1.828 mm*1.04 mm.

[0022] By adopting the above technical solution, the size of the base island and the chip can be adapted to the current production lines on the market.

[0023] In summary, the present application includes at least one of the following beneficial technical effects:

[0024] 1. The height of the base island is lower than the pins, so that the conductive glue flowing from the upper surface of the base island to its side is misaligned with the adjacent pins, avoiding short circuit failure caused by contact between the conductive glue and the pins;

[0025] 2. The area where the pin faces the overflowing portion of the conductive glue is recessed, so that the pin further avoids the area where a short circuit may occur with the conductive glue, thereby improving the safety of the transistor. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 is a schematic cross-sectional structure diagram of the package lead structure of Example 1 of the present application;

[0027] Figure 2 is a top view of the package lead structure of Example 1 of the present application after removing the packaging layer;

[0028] Figure 3 is a schematic cross-sectional structure diagram of the package lead structure of Example 2 of the present application;

[0029] Figure 4 is a top view of the package lead structure of Example 2 of the present application after removing the packaging layer;

[0030] Figure 5 It is a top view of the packaging lead structure of Example 3 of the present application after removing the packaging layer.

[0031] Explanation of the reference numerals: 1. base island; 2. pin; 21. first pin; 22. second pin; 23. third pin; 24. fourth pin; 25. fifth pin; 3. conductive adhesive; 4. recess; 5. chip; 6. bottom support; 7. packaging layer; 8. bottom surface. DETAILED DESCRIPTION

[0032] The following is combined with Figure 1-5 This application is described in further detail.

[0033] Conductive adhesive is a material commonly used in the chip packaging process, which can achieve both electrical and physical connections.

[0034] Since the conductive adhesive is in a liquid or at least fluid state during the connection process, and with the development of technology, the size of electronic components has gradually become smaller, and the pins of each unit have been arranged more densely, there is a risk that the conductive adhesive will flow around and conduct with components outside the design, which undoubtedly increases the scrap rate of chip packaging.

[0035] Therefore, how to avoid accidental contact between conductive adhesive and other components during the production process is of great practical significance for improving the yield rate of mass production of chip packaging units.

[0036] An embodiment of the present application discloses a package lead structure.

[0037] Example 1

[0038] Reference Figure 1 , Figure 2 The package lead structure includes a base 6, a base island 1 disposed on the base 6 and at least one pin 2 facing the base island 1, a chip 5 electrically connected to the surface of the base island 1 through a conductive adhesive 3, and a package layer 7 covering the upper surface of the above components. The side surface of the base 6 away from the package layer is defined as the bottom surface 8 of the package lead structure, and the heights defined below specifically refer to the distance between each structure and the bottom surface 8.

[0039] It should be noted that the package lead structure of the present application has a clear up-down direction during the production process, and the substrate, base island 1 and pin 2, conductive glue 3 and chip 5, and packaging layer 7 are stacked in sequence. Therefore, the "upper", "lower" and height descriptions in the implementation methods of each embodiment have specific meanings in actual production, and the corresponding descriptions are clear and implementable solutions for those skilled in the art.

[0040] The height of the pin 2 is higher than the height of the surface of the island 1 . Specifically, the lower surface of the pin 2 is at the same height as the upper surface of the island 1 , or the lower surface of the pin 2 is higher than the upper surface of the island 1 .

[0041] The upper surface of the base island 1 is rectangular, and the midpoint of the long side of the rectangle is closest to the orthographic projection of the pin 2 on the upper surface of the base island 1. The upper surface of the base island 1 is coated with a conductive adhesive 3, which flows around to the side of the base island 1. Specifically, at least the edge of the side of the base island 1 close to the pin 2 and in contact with its upper surface is covered by the conductive adhesive 3.

[0042] The chip 5 is adhered to the upper surface of the base island 1 by the conductive adhesive 3 , and there is a gap between the conductive adhesive 3 and the pins 2 .

[0043] The base 6 is preferably a ceramic base 6, and the material of the packaging layer 7 can be one or more of epoxy resin, silicone resin, polyimide and acrylic resin.

[0044] Illustratively, in a preferred implementation of the present embodiment, the thickness of the pin 2 is 0.1 mm, and the upper surface of the base island 1 is 0.127 mm lower than the upper surface of the pin 2; the upper surface of the base island 1 is a rectangle of 1.828 mm*1.04 mm, and the orthographic projection of the chip 5 on the upper surface of the base island 1 is a rectangle of 1.6 mm*0.85 mm.

[0045] It should be noted that, in this embodiment, the pin 2 is described as being arranged on the base 6, which does not specifically mean that the lower surface of the pin 2 is completely attached and fixed to the base 6. In fact, in this embodiment, there is a gap between the pin 2 and the base 6 on the side close to the base island 1 to accommodate the overflowed conductive glue 3. This gap will be filled with packaging glue in the subsequent packaging and become a part of the packaging layer 7.

[0046] The implementation principle of Example 1 is:

[0047] When the conductive adhesive 3 is still in a fluid state, because the chip 5 and the base island 1 are close to each other, the conductive adhesive 3 between the two is squeezed, flows around and makes part of the conductive adhesive 3 go over the edge of the upper surface of the base island 1. In consideration of saving space, the pins 2 of the package lead structure are usually arranged in the area directly opposite to the long side of the base island 1 to ensure that the package layer 7 that encapsulates the base island 1 and the pins 2 together has a relatively regular shape. This design also makes it easier for the conductive adhesive 3 to overflow to the side of the base island 1 directly opposite to the pins 2, resulting in accidental contact between the conductive adhesive 3 and the pins 2, and then causing a short circuit between the base island 1 and the pins 2.

[0048] The reason for the short circuit is that the overflow of the conductive adhesive 3 fills the narrow gap between the base island 1 and the pin 2, destroying the electrical insulation between the two. In this embodiment, because the height of the base island 1 is lower than the pin 2, and even the upper surface of the base island 1 is lower than the lower surface of the pin 2, the conductive adhesive 3 does not pass through the plane where the pin 2 is located when the conductive adhesive 3 spreads over the edge of the base island 1 and adheres to the side of the base island 1. Even if the projections of the two on the upper surface of the base island 1 interfere, in three-dimensional space, the conductive adhesive 3 will pass under the pin 2 without contact.

[0049] Therefore, the package lead structure provided in this embodiment can effectively avoid the contact between the conductive adhesive 3 and the pin 2, and further avoid the short circuit between the pin 2 and the base island 1, which improves the yield rate of the package lead structure production and is conducive to improving the efficiency of production and manufacturing.

[0050] Example 2

[0051] Reference Figure 3 , Figure 4The package lead structure includes a base 6, a base island 1 arranged on the base 6 and at least one pin 2 facing the base island 1, a chip 5 electrically connected to the surface of the base island 1 through a conductive adhesive 3, and a packaging layer 7 covering the upper surface of the above components.

[0052] The height of the pin 2 is higher than the height of the surface of the island 1 . Specifically, the lower surface of the pin 2 is higher than the upper surface of the island 1 .

[0053] The upper surface of the base island 1 is coated with conductive glue 3 , and the chip 5 is adhered to the upper surface of the base island 1 by the conductive glue 3 . The conductive glue 3 flows around to the side of the base island 1 , and there is a gap between the conductive glue 3 and the pin 2 .

[0054] The pin 2 is provided with a clearance groove 4 on one side close to the base island 1 to prevent the conductive adhesive 3 from contacting the pin 2 . Specifically, the projection of the clearance groove 4 on the upper surface of the base island 1 is an arc or a triangle.

[0055] Illustratively, in a preferred implementation of the present embodiment, the thickness of the pin 2 is 0.1 mm, and the upper surface of the base island 1 is 0.127 mm lower than the upper surface of the pin 2; the upper surface of the base island 1 is a rectangle of 1.828 mm*1.04 mm, and the orthographic projection of the chip 5 on the upper surface of the base island 1 is a rectangle of 1.6 mm*0.85 mm, and the depth of the make way groove 4 is 0.05 mm.

[0056] The implementation principle of Example 2 is:

[0057] The pin 2 is concave on the side close to the base island 1, so that the gap between the conductive adhesive 3 and the pin 2 is further increased, the risk of the conductive adhesive 3 contacting the pin 2 is further reduced, and the yield rate of the chip 5 package is increased.

[0058] Example 3

[0059] Reference Figure 5 The package lead structure includes a base 6, a base island 1 and five pins 2 arranged on the base 6, a chip 5 electrically connected to the surface of the base island 1 through a conductive adhesive 3, and a packaging layer 7 covering the upper surfaces of the above components.

[0060] The pins 2 include a first pin 21, a second pin 22, a third pin 23, a fourth pin 24 and a fifth pin 25 which are arranged around the base 6, wherein, on the upper surface of the base island 1, the distance between the orthographic projection of the first pin 21 and the base island 1 is closest, and the height of the first pin 21 is higher than the height of the surface of the base island 1, specifically, the lower surface of the first pin 21 is higher than the upper surface of the base island 1.

[0061] The upper surface of the base island 1 is coated with conductive glue 3, and the chip 5 is adhered to the upper surface of the base island 1 by the conductive glue 3. The conductive glue 3 flows around to the side of the base island 1, and there are gaps between the conductive glue 3 and the first pin 21, the second pin 22, the third pin 23, the fourth pin 24 and the fifth pin 25.

[0062] The pin 2 is provided with a clearance groove 4 on one side close to the base island 1 to prevent the conductive adhesive 3 from contacting the first pin 21 . Specifically, the projection of the clearance groove 4 on the upper surface of the base island 1 is an arc or a triangle.

[0063] Illustratively, in a preferred implementation scheme of the present embodiment, the thickness of the first pin 21, the second pin 22, the third pin 23, the fourth pin 24 and the fifth pin 25 are all 0.1 mm, and the upper surface of the base island 1 is 0.127 mm lower than the upper surface of the first pin 21; the upper surface of the base island 1 is a rectangle of 1.828 mm*1.04 mm, and the orthographic projection of the chip 5 on the upper surface of the base island 1 is a rectangle of 1.6 mm*0.85 mm, and the depth of the make way groove 4 is 0.05 mm.

[0064] The implementation principle of Example 3 is:

[0065] This embodiment provides a chip 5 packaging structure with multiple pins, and its implementation principle is the same as that of Embodiment 1 and Embodiment 2.

[0066] It should be noted that this embodiment only provides a specific implementation scheme for a multi-pin 2 packaging structure. Under the premise of limiting the first pin 21 that is most likely to short-circuit in the packaging structure, it should be obvious to technicians in this field how to avoid short-circuiting between the remaining pins 2 and the base island 1 and the conductive adhesive 3, so it is not elaborated here.

[0067] The above are all preferred embodiments of the present application, and the protection scope of the present application is not limited thereto. Therefore, any equivalent changes made according to the structure, shape, and principle of the present application should be included in the protection scope of the present application.

Claims

1. A package lead structure, comprising a base island (1) and at least one pin (2) directly facing the base island (1), characterized in that: The package lead structure comprises a bottom surface (8), and a height of the base island (1) from the bottom surface (8) is lower than a height of the pin (2) from the bottom surface (8).

2. The package lead structure according to claim 1, characterized in that: The lower surface of the pin (2) is flush with the upper surface of the base island (1), or the lower surface of the pin (2) is spaced apart from the upper surface of the base island (1).

3. The package lead structure according to claim 1, characterized in that: The upper surface of the base island (1) is 0.127 mm lower than the upper surface of the pin (2).

4. The package lead structure according to claim 3, characterized in that: The thickness of the tube pin (2) is 0.1 mm.

5. The package lead structure according to claim 1, characterized in that: A clearance groove (4) is provided on one side of the tube pin (2) close to the base island (1).

6. The package lead structure according to claim 5, characterized in that: The orthographic projection of the clearance groove (4) on the bottom surface (8) is a triangle.

7. The package lead structure according to claim 5, characterized in that: The orthographic projection of the clearance groove (4) on the bottom surface (8) is an arcuate shape.

8. The package lead structure according to any one of claims 5 to 7, characterized in that: The depth of the clearance groove (4) is 0.05 mm.

9. The package lead structure according to claim 1, characterized in that: A chip (5) is arranged on the upper surface of the base island (1), and the chip (5) is electrically connected to the base island (1) via a conductive adhesive (3).

10. The package lead structure according to claim 9, characterized in that: The orthographic projection of the chip (5) on the upper surface of the base island (1) is a rectangle of 1.6 mm*0.85 mm; and the upper surface of the base island (1) is a rectangle of 1.828 mm*1.04 mm.

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