CN219476674U

CN219476674U - Chip packaging structure

Info

Publication number: CN219476674U
Application number: CN202320669996.XU
Authority: CN
Inventors: 杨彦召; 钱玉; 严曰
Original assignee: China Automotive Innovation Co Ltd
Current assignee: China Automotive Innovation Co Ltd
Priority date: 2023-03-30
Filing date: 2023-03-30
Publication date: 2023-08-04
Anticipated expiration: 2033-03-30

Abstract

The utility model relates to the technical field of chip packaging, and discloses a chip packaging structure, wherein one of a chip and a substrate is provided with a welding convex part, the other is provided with a welding groove, the welding convex part is inserted into the welding groove, and the welding convex part and the inner wall of the welding groove are arranged at intervals, so that the welding groove is provided with a space for accommodating welding flux; the welding layer is formed in the welding groove when the welding convex part is welded and fixed with the inner wall of the welding groove through the welding material by limiting the size of the welding groove and the welding material amount, so that the welding strength between the chip and the substrate can be ensured; the solder layer is not higher than the opening end face of the welding groove, the solder is effectively blocked in a certain area at the bottom of the welding groove, the solder cannot contact with pads on a chip and pins of a lead frame, and the problem of short circuit is effectively avoided.

Description

Chip packaging structure

Technical Field

The present disclosure relates to chip packaging technology, and particularly to a chip packaging structure.

Background

When the chip is soldered to the base of the lead frame, since the base of the lead frame is planar, there may be solder overflow during solder heating and melting to cause shorting of adjacent leads of the lead frame, or solder climbing up to the chip, causing shorting of pads on the chip, which refers to conductive terminals, and the chip or the lead frame base being unclean to reduce soldering strength.

In order to solve the above problems, in the prior art, an annular soldering groove is formed on a lead frame substrate, the annular soldering groove surrounds a chip, overflowed solder is drained into the annular soldering groove, the solder is prevented from flowing outwards, and a support column is formed at the bottom of the chip, so that the contact area between the chip and the solder and between the solder and the substrate is increased, and the soldering strength is further increased.

Although the solder can be drained into the annular soldering groove by arranging the annular soldering groove, the solder still can overflow due to the fluidity of the solder at high temperature, so that a small amount of solder overflows to adjacent pins to cause short circuit.

Disclosure of Invention

The utility model aims to provide a chip packaging structure which can effectively prevent solder from overflowing and can ensure the welding strength between a chip and a substrate.

To achieve the purpose, the utility model adopts the following technical scheme:

the chip packaging structure comprises chips and a substrate which are stacked, wherein one of the chips and the substrate is convexly provided with a welding convex part, and the other one is concavely provided with a welding groove;

the welding convex part is inserted into the welding groove and is arranged at intervals with the inner wall of the welding groove, the welding convex part is welded and fixed with the inner wall of the welding groove through welding flux, a welding flux layer is formed in the welding groove, and the welding flux layer is not higher than the opening end face of the welding groove.

As a preferable embodiment of the above-described chip package structure, a plurality of the soldering lands are provided, and at least two of the soldering lands are inserted into one of the soldering grooves.

As a preferable technical scheme of the chip packaging structure, two adjacent welding convex parts are arranged at intervals.

As a preferable technical scheme of the above chip packaging structure, each of the welding protrusions is inserted into the same welding groove.

As a preferable technical scheme of the chip packaging structure, the chip is provided with the welding convex part, and the substrate is provided with the welding groove; the chip completely covers the soldering bath.

As a preferable technical scheme of the chip packaging structure, the substrate and the opposite side surfaces of the chip are mutually attached.

As a preferable embodiment of the above chip packaging structure, the solder bump has a bump bottom surface facing a bottom wall of the solder trench, and the solder layer is closer to an opening end surface of the solder trench than the bump bottom surface.

As a preferable technical scheme of the chip packaging structure, the bottom surface of the protrusion is arranged at intervals with the bottom wall of the welding groove.

As a preferable technical scheme of the chip packaging structure, the welding groove comprises a groove bottom wall and a groove side wall connected with the groove bottom wall, and the welding convex part and the groove side wall are arranged at intervals.

As a preferable technical scheme of the above chip packaging structure, the welding convex part is provided with a first end and a second end which are distributed oppositely along the thickness direction of the chip, and the first end is connected with the chip;

the outer diameter of the second end is larger than or equal to the outer diameter of the first end.

The utility model has the beneficial effects that: according to the chip packaging structure provided by the utility model, one of the chip and the substrate is provided with the welding convex part, the other is provided with the welding groove, the welding convex part is inserted into the welding groove, and the welding convex part is arranged at intervals with the inner wall of the welding groove, so that the welding groove is provided with a space for accommodating welding flux; the welding convex part and the inner wall of the welding groove are welded and fixed through the welding flux by limiting the size of the welding groove and the welding flux, and a welding flux layer is formed in the welding groove, so that the welding strength between the chip and the substrate can be ensured; the solder layer is not higher than the opening end face of the welding groove, the solder is effectively blocked in a certain area at the bottom of the welding groove, the solder cannot contact with pads on a chip and pins of a lead frame, and the problem of short circuit is effectively avoided.

Drawings

In order to more clearly illustrate the technical solutions of the embodiments of the present utility model, the following description will briefly explain the drawings needed in the description of the embodiments of the present utility model, and it is obvious that the drawings in the following description are only some embodiments of the present utility model, and other drawings may be obtained according to the contents of the embodiments of the present utility model and these drawings without inventive effort for those skilled in the art.

Fig. 1 is a cross-sectional view of a chip package structure provided by an embodiment of the present utility model;

FIG. 2 is an exploded view of a chip package structure provided by an embodiment of the present utility model;

fig. 3 is a schematic diagram of a chip according to an embodiment of the present utility model.

In the figure:

1. a substrate; 11. a welding groove; 111. a bottom wall of the tank; 112. a groove sidewall; 113. an open end face;

2. a chip; 21. welding the convex part; 211. a convex bottom surface;

3. and (5) a solder layer.

Detailed Description

The utility model is described in further detail below with reference to the drawings and examples. It is to be understood that the specific embodiments described herein are merely illustrative of the utility model and are not limiting thereof. It should be further noted that, for convenience of description, only some, but not all of the structures related to the present utility model are shown in the drawings.

In the description of the present utility model, unless explicitly stated and limited otherwise, the terms "connected," "connected," and "fixed" are to be construed broadly, and may be, for example, fixedly connected, detachably connected, or integrally formed; can be mechanically or electrically connected; can be directly connected or indirectly connected through an intermediate medium, and can be communicated with the inside of two elements or the interaction relationship of the 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.

In the present utility model, unless expressly stated or limited otherwise, a first feature "above" or "below" a second feature may include both the first and second features being in direct contact, as well as the first and second features not being in direct contact but being in contact with each other through additional features therebetween. Moreover, a first feature being "above," "over" and "on" a second feature includes the first feature being directly above and obliquely above the second feature, or simply indicating that the first feature is higher in level than the second feature. The first feature being "under", "below" and "beneath" the second feature includes the first feature being directly under and obliquely below the second feature, or simply means that the first feature is less level than the second feature.

In the description of the present embodiment, the terms "upper", "lower", "right", etc. orientation or positional relationship are based on the orientation or positional relationship shown in the drawings, and are merely for convenience of description and simplicity of operation, and do not indicate or imply that the apparatus or elements referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus should not be construed as limiting the utility model. Furthermore, the terms "first," "second," and the like, are used merely for distinguishing between descriptions and not for distinguishing between them.

As shown in fig. 1 and 2, the present embodiment provides a chip package structure including a chip 2 and a lead frame, wherein the lead frame has a substrate 1, and the chip 2 and the substrate 1 are stacked; the side surface of the chip 2 facing the substrate 1 is convexly provided with a welding convex part 21, and the side surface of the substrate 1 facing the chip 2 is concavely provided with a welding groove 11; the welding convex part 21 is inserted into the welding groove 11, the welding convex part 21 and the inner wall of the welding groove 11 are welded and fixed by welding flux, a welding flux layer 3 is formed in the welding groove 11, and the welding flux layer 3 is not higher than the opening end face 113 of the welding groove 11; the welding projection 21 is provided at a distance from the inner wall of the welding groove 11. In other embodiments, the soldering bump 21 may be provided on the substrate 1 and the soldering groove 11 may be provided on the chip 2.

In the chip packaging structure provided by the embodiment, one of the chip 2 and the substrate 1 is provided with the welding convex part 21, the other is provided with the welding groove 11, the welding convex part 21 is inserted into the welding groove 11, and the welding convex part 21 is arranged at intervals with the inner wall of the welding groove 11, so that the welding groove 11 is provided with a space for accommodating solder; by limiting the size and the solder amount of the soldering bath 11, the soldering convex part 21 and the inner wall of the soldering bath 11 are fixed by solder soldering, and the soldering layer 3 is formed in the soldering bath 11, so that the soldering strength between the chip 2 and the substrate 1 can be ensured; the solder layer 3 is not higher than the opening end face 113 of the soldering groove 11, and effectively blocks the solder in a certain area at the bottom of the soldering groove 11, so that the solder cannot contact with pads on the chip 2 and pins of the lead frame, and the problem of short circuit is effectively avoided.

Alternatively, the welding mode may be reflow welding, ultrasonic welding, or the like, and ultrasonic welding is preferably adopted.

Optionally, a plurality of welding protrusions 21 are provided, at least two welding protrusions 21 are inserted into one welding groove 11, the number of the welding grooves 11 is reduced, and processing cost is reduced. In the present embodiment, all the welding projections 21 are inserted into the same welding groove 11.

In this embodiment, the plurality of welding protrusions 21 are distributed in an array. Such as a plurality of welding projections 21 in a row-column array or a circumferential array. Illustratively, as shown in fig. 3, the plurality of welding projections 21 are distributed in a 6×4 array. The distribution form of the plurality of soldering lands 21 is not limited to the above-described distribution form, and the distribution form of the plurality of soldering lands 21 may be determined according to the type of chip 2.

The shape of the welding groove 11 depends on the distribution form of the plurality of welding projections 21, and the welding groove 11 may be a rectangular groove, a circular groove, an elliptical groove, various irregular grooves, or the like. Illustratively, when the plurality of welding projections 21 are distributed in a row-column array, the welding groove 11 is a rectangular groove.

Alternatively, the chip 2 entirely covers the soldering bath 11. Specifically, the projection of the opening of the soldering bath 11 onto the opening end face 113 thereof is S1, the projection of the chip 2 onto the opening end face 113 of the soldering bath 11 is S2, and S1 falls completely within S2. With this arrangement, the solder is prevented from climbing up to the surface of the chip 2 along the side wall of the chip 2.

Alternatively, the opposite sides of the substrate 1 and the chip 2 are attached to each other. In this way, the chip 2 can be flatly attached to the substrate 1, the chip 2 is supported by the substrate 1, and the solder layer 3 formed by the inclination of the chip 2 is prevented from being inclined to affect the soldering effect and increase the packaging defective rate in the process of soldering the soldering convex portion 21 with the inner wall of the soldering groove 11 by the solder.

Further, the soldering bath 11 includes a bath bottom wall 111 and a bath side wall 112 that adjoins the bath bottom wall 111, and the soldering convex portion 21 has a convex bottom surface 211 that faces the bath bottom wall 111, and the solder layer 3 is closer to the opening end surface 113 of the soldering bath 11 than the convex bottom surface 211. By this arrangement, the end of the welding projection 21 near the bottom wall 111 of the groove can be completely covered with the solder, the contact area between the welding projection 21 and the solder can be increased, and the welding strength of the welding projection 21 and the inner wall of the welding groove 11 by the solder can be improved.

Alternatively, the welding convex portion 21 is provided at a distance from the groove bottom wall 111 of the welding groove 11, so that the contact area of the solder and the welding convex portion 21 can be increased, thereby improving the welding strength of the welding convex portion 21 and the inner wall of the welding groove 11 by the solder.

Alternatively, the soldering convex portion 21 is provided at a distance from the groove side wall 112, and the contact area of the solder and the soldering convex portion 21 is increased, thereby improving the soldering strength of the soldering convex portion 21 and the inner wall of the soldering groove 11 by the solder.

Alternatively, two adjacent soldering lands 21 are provided at a spacing to provide a sufficient accommodation space for the solder, and the contact area of the solder with each soldering land 21 is increased, thereby improving the soldering strength of the soldering lands 21 and the inner wall of the soldering bath 11 by the solder.

Further, the soldering bump 21 has a first end and a second end which are distributed oppositely in the thickness direction of the chip 2, the first end being connected to the chip 2; the outer diameter of the second end is larger than or equal to that of the first end. By doing so, the contact area between the solder and the soldering convex portion 21 can be increased, thereby improving the stability of soldering of the soldering convex portion 21 and the inner wall of the soldering bath 11 by the solder. The welding protrusion 21 may have a stepped structure or a truncated cone structure. In the present embodiment, the soldering bump 21 has a stepped structure, the small diameter end of the soldering bump 21 is connected to the chip 2, and the large diameter end of the soldering bump 21 is provided near the groove bottom wall 111.

The cross section of the welding boss 21 may be circular, rectangular, or the like, and the cross section of the welding boss 21 is rectangular as shown in fig. 3, for example.

Alternatively, the material of the solder bump 21 is the same as the substrate material at the bottom of the chip 2, and a metal material or a non-metal material may be selected. When a metal material is selected, the material of the welding protrusion 21 may be any one of gold, copper and aluminum, or any one of Jin Tong alloy, gold-aluminum alloy, copper-aluminum alloy or gold-copper-aluminum alloy, which are all known in the art, and the mass components thereof are not described in detail herein.

Furthermore, the foregoing description of the preferred embodiments and the principles of the utility model is provided herein. It will be understood by those skilled in the art that the present utility model is not limited to the particular embodiments described herein, but is capable of various obvious changes, rearrangements and substitutions as will now become apparent to those skilled in the art without departing from the scope of the utility model. Therefore, while the utility model has been described in connection with the above embodiments, the utility model is not limited to the embodiments, but may be embodied in many other equivalent forms without departing from the spirit or scope of the utility model, which is set forth in the following claims.

Claims

1. The chip packaging structure comprises a chip (2) and a substrate (1) which are stacked, wherein one of the chip (2) and the substrate (1) is convexly provided with a welding convex part (21), and the other is concavely provided with a welding groove (11);

the welding device is characterized in that the welding convex parts (21) are inserted into the welding groove (11) and are arranged at intervals with the inner wall of the welding groove (11), the welding convex parts (21) and the inner wall of the welding groove (11) are welded and fixed through welding flux, a welding flux layer (3) is formed in the welding groove (11), and the welding flux layer (3) is not higher than an opening end face (113) of the welding groove (11).

2. The chip package structure according to claim 1, wherein a plurality of the soldering lands (21) are provided, and at least two of the soldering lands (21) are inserted into one of the soldering grooves (11).

3. Chip packaging structure according to claim 2, characterized in that two adjacent soldering bumps (21) are arranged at a distance from each other.

4. Chip packaging structure according to claim 2, characterized in that all the soldering bumps (21) are inserted into the same soldering groove (11).

5. Chip packaging structure according to claim 4, characterized in that the chip (2) is provided with the soldering bumps (21), the substrate (1) being provided with the soldering grooves (11); the chip (2) completely covers the soldering grooves (11).

6. The chip packaging structure according to claim 5, wherein the opposite sides of the substrate (1) and the chip (2) are attached to each other.

7. Chip packaging structure according to claim 1, characterized in that the soldering bump (21) has a bump bottom surface (211) facing the bottom wall (111) of the soldering bath (11), the solder layer (3) being closer to the open end face (113) of the soldering bath (11) than the bump bottom surface (211).

8. The chip packaging structure according to claim 7, wherein the convex bottom surface (211) is spaced apart from the groove bottom wall (111) of the soldering groove (11).

9. The chip packaging structure according to claim 8, wherein the soldering groove (11) includes a groove bottom wall (111) and a groove side wall (112) connected to the groove bottom wall (111), and the soldering convex portion (21) is disposed at a distance from the groove side wall (112).

10. The chip packaging structure according to any one of claims 1 to 9, wherein the soldering bump (21) has a first end and a second end which are distributed opposite to each other in a thickness direction of the chip (2), the first end being connected to the chip (2);