CN117393530A - Packaging frame structure and corresponding preparation method - Google Patents

Abstract

The invention relates to the technical field of semiconductor packaging, and provides a packaging frame structure and a corresponding preparation method. The stacked structure is adopted, a plurality of metal strips or metal leads are bonded in the Z-direction space of the package is expanded, and the flow conductivity of the product is improved; and the space of the pins of the lead frame is fully utilized, and the packaging performance is improved.

Description

Packaging frame structure and corresponding preparation method

Technical Field

The invention relates to the technical field of semiconductor packaging, in particular to a packaging frame structure and a corresponding preparation method.

Background

In the bonding process of the semiconductor package, a chip is generally attached to the surface of a lead frame base island, an aluminum strip is bonded to a welding spot of a lead frame pin from a chip pressing area, and in the bonding process, the lead frame base island and the lead frame pin are subjected to sufficient space lamination to obtain good bonding workability; when electrical demands require bonding of multiple aluminum strips or bonding of multiple leads, the size of the leadframe pins is often limited so that there is no space for the multiple aluminum strips or leads.

Disclosure of Invention

The invention aims to solve the problem that the size limitation of the pins of the existing lead frame does not have space arrangement of a plurality of aluminum strips or leads, and provides a packaging frame structure and a corresponding preparation method.

In order to achieve the above object, the present invention provides a package frame structure, comprising:

lead frame islands and lead frame pins;

the chip is positioned on the surface of the lead frame base island;

a first metal strap connecting the chip and the leadframe pins;

and the metal connecting piece is positioned above the first metal belt and is used for connecting the chip and the lead frame pins.

As an embodiment, the first metal strip includes a first connection portion and a second connection portion, and the metal connection member includes a third connection portion and a fourth connection portion; the first connecting part is connected with the surface of the chip, and the second connecting part is connected with the surface of the pin of the lead frame; the third connecting portion is connected with the surface of the chip, and the fourth connecting portion is connected with the surface of the second connecting portion, so that the third connecting portion is connected with the surface of the pin of the lead frame through the second connecting portion.

As an embodiment, the first metal strip includes a first connection portion and a second connection portion, and the metal connection member includes a third connection portion and a fourth connection portion; the first connecting part is connected with the surface of the chip, and the second connecting part is connected with the surface of the pin of the lead frame; the third connecting portion is connected with the first connecting portion surface so as to be connected with the chip surface through the first connecting portion, and the fourth connecting portion is connected with the second connecting portion surface so as to be connected with the lead frame pin surface through the second connecting portion.

As an embodiment, the fourth connection portion and the second connection portion have a first soldering tab therebetween.

As an embodiment, a second soldering lug is provided between the third connection portion and the first connection portion.

As an embodiment, the metal connection is a second metal strap or a metal lead.

As an embodiment, the number of the second metal strips or metal leads is 1 or more.

Correspondingly, the invention also provides a preparation method of the packaging frame structure, which comprises the following steps:

providing a lead frame, wherein the lead frame comprises a lead frame base island and lead frame pins;

arranging a chip on the surface of the lead frame base island;

connecting the chip and the leadframe pins using a first metal strap;

and arranging a metal connecting piece above the first metal belt and connecting the chip and the lead frame pins.

As an embodiment, the first metal strip includes a first connection portion and a second connection portion, and the metal connection member includes a third connection portion and a fourth connection portion;

the step of connecting the first metal strap to the chip and the leadframe pin includes:

connecting the first connecting part with the surface of the chip, and connecting the second connecting part with the surface of the pin of the lead frame;

the step of connecting the metal connector to the chip and the leadframe pin includes:

and connecting the third connecting part with the surface of the chip, and connecting the fourth connecting part with the surface of the second connecting part so as to connect with the lead frame pins through the second connecting part.

As an embodiment, the first metal strip includes a first connection portion and a second connection portion, and the metal connection member includes a third connection portion and a fourth connection portion;

the step of connecting the first metal strap to the chip and the leadframe pin includes:

connecting the first connecting part with the surface of the chip, and connecting the second connecting part with the surface of the pin of the lead frame;

the step of connecting the metal connector to the chip and the leadframe pin includes:

and connecting the third connecting part with the surface of the first connecting part so as to connect with the surface of the chip through the first connecting part, and connecting the fourth connecting part with the surface of the second connecting part so as to connect with the surface of the pin of the lead frame through the second connecting part.

As an embodiment, the step of connecting the fourth connecting portion and the second connecting portion surface includes:

and arranging a first soldering lug on the surface of the second connecting part, and arranging a fourth connecting part on the surface of the first soldering lug, so that the fourth connecting part is connected with the surface of the second connecting part through the first soldering lug.

As an embodiment, the step of connecting the third connecting portion and the first connecting portion surface includes:

and arranging a second soldering lug on the surface of the first connecting part, and arranging a third connecting part on the surface of the second soldering lug, so that the third connecting part is connected with the surface of the first connecting part through the second soldering lug.

As an embodiment, the metal connection is a second metal strap or a metal lead.

The invention has the beneficial effects that: the invention provides a packaging frame structure and a corresponding preparation method. By adopting the stacked structure, a plurality of metal strips or metal leads are bonded in the Z-direction space of the package, and the flow conductivity of the product is improved; and the space of the pins of the lead frame is fully utilized, and the packaging performance is improved.

Drawings

Fig. 1 is a schematic diagram of a package structure according to some embodiments of the present invention;

FIG. 2 is a cross-sectional view of the AA position of FIG. 1;

fig. 3 is a schematic view of a package frame according to some embodiments of the present invention;

FIG. 4 is a cross-sectional view of the BB site of FIG. 3;

fig. 5-6 are schematic views of two other package frame structures according to some embodiments of the present invention;

fig. 7 is a schematic view of a package frame with a first solder tab according to some embodiments of the present invention;

FIG. 8 is a cross-sectional view of the CC site of FIG. 7;

FIG. 9 is a schematic diagram of a package frame with a first bonding pad and a second bonding pad according to some embodiments of the present invention;

FIG. 10 is a cross-sectional view of the DD in FIG. 9;

FIG. 11 is a diagram showing an example of the location of the press-region on the surface of the chip;

fig. 12 is a process diagram of a package frame structure according to some embodiments of the present invention.

Detailed Description

The following description of the embodiments of the present invention will be made clearly and completely with reference to the accompanying drawings, in which it is apparent that the embodiments described are only some embodiments of the present invention, but not all embodiments. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to be within the scope of the invention.

It will be understood that, as used herein, terms such as "first," "second," and "third," etc., describe various elements, components, regions, layers and/or sections that should not be limited by these terms. Such terms may be used merely to distinguish one element, component, region, layer or section from another element, component, region, layer or section. The terms such as "first," "second," and "third" when used herein do not imply a sequence or order unless clearly indicated by the context.

In this document, unless explicitly specified and limited otherwise, the terms "connected," "connected," and the like are to be construed broadly, and may be, for example, fixedly connected, detachably connected, or integrally formed; can be mechanically or electrically connected; either directly or indirectly, through intermediaries, or both, may be in communication with each other or in interaction with each other, unless expressly defined otherwise. The specific meaning of the terms in this application will be understood by those of ordinary skill in the art as the case may be.

For ease of description, spatially relative terms such as "under," "above," "over," "upper," and the like may be used herein to describe one element or feature's relationship to another element or feature as illustrated in the figures. It will be understood that spatially relative terms are intended to encompass different orientations of the device in use or operation in addition to the orientation depicted in the figures. For example, if the device in the figures is turned over, elements described as "below" or "beneath" other elements or features would then be oriented "above" the other elements or features. Thus, the term "below" may include both above and below orientations.

In the description of the present specification, a description referring to terms "one embodiment," "some embodiments," "examples," "specific examples," or "some examples," etc., means that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the present invention. In this specification, schematic representations of the above terms are not necessarily directed to the same embodiment or example. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples. Furthermore, the different embodiments or examples described in this specification and the features of the different embodiments or examples may be combined and combined by those skilled in the art without contradiction.

Reference is made to fig. 1 for a package structure provided in some embodiments, and fig. 2 is a cross-sectional view of the AA position in fig. 1, including: a lead frame base 1 and a lead frame pin 6; a chip 2 positioned on the surface of the lead frame base island 1; a first metal strap 3 connecting the chip 2 and the leadframe pin 6. It can be seen that the size of the leadframe pins 6 is limited and that no more metal strips or wires can be soldered, resulting in a limited amount of current that can be conducted. For example, the chip 2 may be a power device triode, the first metal strap 3 may be an aluminum strap, one end of the aluminum strap is connected to a source electrode of the power device triode, and the other end of the aluminum strap is connected to a lead frame pin 6; when more aluminum strips cannot be directly welded, the triode of the power device can be conducted with limited current, so that tube explosion easily occurs when large current flows, and the stability of the product is poor.

To this end, referring to fig. 3, some embodiments of the present invention provide a package frame structure, including:

a leadframe base island 10 and leadframe pins 60;

a chip 20 located on the surface of the lead frame base island 10;

a first metal strap 30 connecting the chip 20 and the leadframe pins 60;

a metal connection 40 over the first metal strap 30 and connecting the chip 20 and the leadframe pins 60.

Some embodiments of the present invention provide for providing metal connectors 40 over the first metal strap 30 that electrically connect the chip 20 and the leadframe pins 60, so that more metal connectors 40 may be soldered to the leadframe pins 60 while the leadframe pins 60 are limited in size. The first metal strip 30 includes a first connection portion 31 and a second connection portion 32; the metal connector 40 includes a third connecting portion 41 and a fourth connecting portion 42.

Some embodiments of the invention adopt a stacked structure, expand the packaging Z-direction space and bond a plurality of metal connectors 40, and improve the flow conductivity of the product; and the space of the welding spots is fully utilized, and the packaging performance is improved. Wherein the Z-direction space is a space perpendicular to the direction of the first metal strip.

In some embodiments, the chip 20 may be a high voltage high power chip requiring high on-current, such as: power device transistors, insulated gate bipolar transistors (IGBT transistors) or field effect transistors (MOS transistors), etc. Wherein the surface of the chip 20 includes a plurality of press nips, referring to fig. 11, a schematic diagram of the surface of the chip 20 including 3 press nips, which are distinguished by dotted lines. In an embodiment, the first connection portion 31 and the third connection portion 41 may be stacked in the same nip on the surface of the chip 20, or may be located in parallel in the same nip on the surface of the chip 20. In one embodiment, the first metal strip 30 and the metal connection 40 may be connected to different pressure areas on the surface of the chip 20; that is, the first connection portion 31 and the third connection portion 41 may be located in different pressure areas of the surface of the chip 20, respectively. For example, when the chip 20 is a power device transistor, the surface of the power device transistor has a source, a gate and a drain, the first metal strap 30 and the metal connector 40 are all connected to the source of the surface of the power device transistor, and the source of the surface of the power device transistor corresponds to at least one of the voltage areas, that is, the first metal strap 30 and the metal connector 40 may be connected to the same voltage area corresponding to the source, or the first metal strap 30 and the metal connector 40 may be respectively connected to different voltage areas corresponding to the source.

In some embodiments, the first metal strip 30 may be an aluminum strip, a gold strip, a silver strip, a copper strip, or the like. In some embodiments, referring to fig. 3, the metal connector 40 may be a second metal strap and the first metal strap 30 may be an aluminum strap, a gold strap, a silver strap, a copper strap, or the like. In some embodiments, referring to fig. 5, the metal connector 40 may also be a metal wire, which may be an aluminum wire, gold wire, silver wire, copper wire, or the like. It should be noted that, in the package frame structure provided in the different embodiments of the present invention, the metal connecting piece 40 may be either a second metal strip or a metal lead, and the number of the second metal strip or the metal lead is 1 or more.

In some embodiments, the first metal strap 30 includes a first connection portion 31 and a second connection portion 32, and the first metal strap 30 is electrically connected to the chip 20 and the leadframe pin 60 through the first connection portion 31 and the second connection portion 32, respectively; the metal connector 40 includes a third connection portion 41 and a fourth connection portion 42, and the metal connector 40 is electrically connected to the chip 10 and the lead frame pin 60 through the third connection portion 41 and the fourth connection portion 42, respectively. In an embodiment, when the size of the lead frame pin 60 is limited and a certain space is left on the surface of the chip 30, referring to fig. 3 and 4, fig. 4 is a cross-sectional view of the BB position in fig. 3, the first connection portion 31 may be connected to the surface of the chip 20, and the second connection portion 32 may be connected to the surface of the lead frame pin 60; the third connection portion 41 is connected to the surface of the chip 20, and the fourth connection portion 42 is connected to the surface of the second connection portion 32, so that the fourth connection portion 42 is connected to the surface of the lead frame pin 60 through the second connection portion 32. In an embodiment, when the sizes of the lead frame pins 60 and the chip 30 are limited, referring to fig. 5, the first connection portion 31 may be connected to the surface of the chip 20, and the second connection portion 32 may be connected to the surface of the lead frame pins 60; the third connection portion 41 is connected to the surface of the first connection portion 31, so that the third connection portion 41 is connected to the surface of the chip 20 through the first connection portion 31, and the fourth connection portion 42 is connected to the surface of the second connection portion 32, so that the fourth connection portion 42 is connected to the surface of the lead frame pin 60 through the second connection portion 32.

However, in other embodiments, although the length of the lead frame pin 60 is limited, the fourth connection portion 42 and the surface of the lead frame pin 60 may be connected, as the width of the lead frame pin 60 is allowed, with reference to fig. 6.

In some embodiments, referring to fig. 4, the first metal strip 30 further includes a first middle portion 33 between the first connection portion 31 and the second connection portion 32, the metal connection member 40 further includes a second middle portion 43 between the third connection portion 41 and the fourth connection portion 42, and when the metal connection member 40 is located above the first metal strip 30, the first middle portion 33 may be in contact with the second middle portion 43, and the first middle portion 33 may not be in contact with the second middle portion 43, so that an effect of increasing the on-current may be achieved.

In some embodiments, referring to fig. 7 and 8, fig. 8 is a cross-sectional view of the CC position of fig. 7, when the fourth connection portion 42 and the second connection portion 32 are connected, the fourth connection portion 43 and the second connection portion 32 have the first tab 51 therebetween. In some embodiments, referring to fig. 9 and 10, fig. 10 is a cross-sectional view of the DD position of fig. 9, the third connecting portion 41 and the first connecting portion 31 further have a second tab 52 when the third connecting portion 41 and the first connecting portion 31 are connected. The first soldering tab 51 and the second soldering tab 52 may provide better welding performance, and more stable quality protection for the metal connector assembly.

Some embodiments of the present invention further provide a method for manufacturing a package frame structure, referring to fig. 12, which is a schematic diagram of a manufacturing process, including the following steps:

as in (a) of fig. 12, a lead frame is provided, the lead frame including a lead frame island 10 and lead frame pins 60; a chip 20 is arranged on the surface of the lead frame base island 10; as in (b) of fig. 12, the chip 20 and the leadframe pins 60 are electrically connected using a first metal strip 30;

in some embodiments, the first metal strip 30 includes a first connection portion 31 and a second connection portion 32; the step of connecting the first metal strap 30 to the chip 20 and the leadframe pins 60 includes:

connecting the first connection portion 31 to the surface of the chip 20, and connecting the second connection portion 32 to the surface of the lead frame pin 60; thereby enabling the first metal strap 30 to connect the chip 20 and the leadframe pins 60.

As further shown in fig. 12 (c) and (d), a metal connector 40 is provided over the first metal strap 30 and connects the chip 20 and the leadframe pins 60.

In some embodiments, as shown in (d) of fig. 12, the metal connector 40 includes a third connecting portion 41 and a fourth connecting portion 42; the step of connecting the metal connector 40 to the chip 20 and the leadframe pin 60 includes:

the third connection part 41 is connected to the surface of the chip 230, and the fourth connection part 42 is connected to the surface of the second connection part 32 so as to be connected to the lead frame pin 60 through the second connection part 32.

In some embodiments, as shown in (c) of fig. 12, the step of connecting the fourth connection portion 42 and the surface of the second connection portion 32 includes:

the first soldering tab 51 is disposed on the surface of the second connection portion 32, and the fourth connection portion 42 is disposed on the surface of the first soldering tab 51, so that the fourth connection portion 42 is connected to the surface of the second connection portion 32 through the first soldering tab 51.

In other embodiments, however, the step of connecting the metal connector 40 to the chip 20 and the leadframe pin 60 may also include:

the third connection portion 41 is connected to the surface of the first connection portion 31 so as to be connected to the surface of the chip 20 through the first connection portion 31, and the fourth connection portion 42 is connected to the surface of the second connection portion 32 so as to be connected to the surface of the lead frame pin 60 through the second connection portion 32.

In some embodiments, the step of connecting the third connecting portion 41 and the surface of the first connecting portion 31 includes:

the second tab 52 is disposed on the surface of the first connection portion 31, and the third connection portion 41 is disposed on the surface of the second tab 52, so that the third connection portion 41 is connected to the surface of the first connection portion 31 through the second tab 52.

And then encapsulating the chip 20, the first metal strip 30 and the metal connection piece 40 to obtain an encapsulated structure shown in fig. 12 (e), and then cutting to obtain a single encapsulated structure shown in fig. 12 (f).

Although the present invention has been described with respect to the preferred embodiments, it is not intended to be limited thereto, and any person skilled in the art can make any possible variations and modifications to the technical solution of the present invention by using the methods and techniques disclosed herein without departing from the spirit and scope of the present invention.

Claims (13)

1. A package frame structure, comprising:

lead frame islands and lead frame pins;

the chip is positioned on the surface of the lead frame base island;

a first metal strap connecting the chip and the leadframe pins;

and the metal connecting piece is positioned above the first metal belt and is used for connecting the chip and the lead frame pins.

2. The package frame structure of claim 1, wherein the first metal strap includes a first connection portion and a second connection portion, and the metal connection member includes a third connection portion and a fourth connection portion; the first connecting part is connected with the surface of the chip, and the second connecting part is connected with the surface of the pin of the lead frame; the third connecting portion is connected with the surface of the chip, and the fourth connecting portion is connected with the surface of the second connecting portion, so that the fourth connecting portion is connected with the surface of the lead frame pin through the second connecting portion.

3. The package frame structure of claim 1, wherein the first metal strap includes a first connection portion and a second connection portion, and the metal connection member includes a third connection portion and a fourth connection portion; the first connecting part is connected with the surface of the chip, and the second connecting part is connected with the surface of the pin of the lead frame; the third connecting portion is connected with the surface of the first connecting portion, so that the third connecting portion is connected with the surface of the chip through the first connecting portion, and the fourth connecting portion is connected with the surface of the second connecting portion, so that the fourth connecting portion is connected with the surface of the lead frame pin through the second connecting portion.

4. A package frame structure according to claim 2 or 3, wherein the fourth connection portion and the second connection portion have a first tab therebetween.

5. The package frame structure of claim 3, wherein a second tab is provided between the third connection portion and the first connection portion.

6. The package frame structure of claim 1, wherein the metal connector is a second metal strap or a metal lead.

7. The package frame structure of claim 6, wherein the number of the second metal strips or metal leads is 1 or more.

8. A method of manufacturing a package frame structure, comprising:

providing a lead frame, wherein the lead frame comprises a lead frame base island and lead frame pins;

arranging a chip on the surface of the lead frame base island;

connecting the chip and the leadframe pins using a first metal strap;

and arranging a metal connecting piece above the first metal belt and connecting the chip and the lead frame pins.

9. The method of manufacturing a package frame structure according to claim 8, wherein the first metal strip includes a first connection portion and a second connection portion, and the metal connection member includes a third connection portion and a fourth connection portion;

the step of connecting the first metal strap to the chip and the leadframe pin includes:

connecting the first connecting part with the surface of the chip, and connecting the second connecting part with the surface of the pin of the lead frame;

the step of connecting the metal connector to the chip and the leadframe pin includes:

and connecting the third connecting part with the surface of the chip, and connecting the fourth connecting part with the surface of the second connecting part, so that the fourth connecting part is connected with the lead frame pins through the second connecting part.

10. The method of manufacturing a package frame structure according to claim 8, wherein the first metal strip includes a first connection portion and a second connection portion, and the metal connection member includes a third connection portion and a fourth connection portion;

the step of connecting the first metal strap to the chip and the leadframe pin includes:

connecting the first connecting part with the surface of the chip, and connecting the second connecting part with the surface of the pin of the lead frame;

the step of connecting the metal connector to the chip and the leadframe pin includes:

and connecting the third connecting part with the surface of the first connecting part, so that the third connecting part is connected with the surface of the chip through the first connecting part, and connecting the fourth connecting part with the surface of the second connecting part, so that the fourth connecting part is connected with the surface of the lead frame pin through the second connecting part.

11. The method of manufacturing a package frame structure according to claim 9 or 10, wherein the step of connecting the fourth connection portion and the second connection portion surface includes:

and arranging a first soldering lug on the surface of the second connecting part, and arranging a fourth connecting part on the surface of the first soldering lug, so that the fourth connecting part is connected with the surface of the second connecting part through the first soldering lug.

12. The method of manufacturing a package frame structure according to claim 10, wherein the step of connecting the third connection portion and the first connection portion surface comprises:

and arranging a second soldering lug on the surface of the first connecting part, and arranging a third connecting part on the surface of the second soldering lug, so that the third connecting part is connected with the surface of the first connecting part through the second soldering lug.

13. The method of claim 8, wherein the metal connector is a second metal strip or a metal lead.