Flat no-lead packaging frame structure and corresponding packaging structure

Abstract

The utility model relates to a semiconductor packaging technology, in particular to a flat no-lead packaging frame structure and a packaging structure, and the flat no-lead packaging frame structure comprises a lead frame; the bearing plate is arranged on the back surface of the lead frame; the lead frame comprises a plurality of lead frame units, each lead frame unit comprises a base island and lead bonding pads which are separately arranged around the base island, and connecting ribs are arranged between the lead bonding pads at least located at four corners and the adjacent lead bonding pads corresponding to the adjacent lead frame units. According to the utility model, by adding the connecting ribs between the adjacent lead frame units, the connection between the adjacent lead bonding pads is realized, so that the lead bonding pads corresponding to the two adjacent lead frame units or the four adjacent lead frame units form a whole, and the mold clamping force of the lead bonding pads is larger when a steel plate is torn off; and the lead bonding pad does not fall off when the stainless steel plate is torn.

Description

Technical Field

[0001] This utility model belongs to the field of semiconductor technology, specifically relating to a flat leadless packaging frame structure and a corresponding packaging structure. Background Technology

[0002] QFN (Quad Flat No-lead Package) is a common surface-mount chip package. The QFN package is a padless, square-shaped package with a large exposed base island at the center of the bottom for heat dissipation. Electrically connected pads surround the base island. Because QFN packages have no pads, they occupy a smaller area and have a lower height. They are also small and lightweight, and offer good electrical and thermal performance, making them extremely popular. With the increasing demand for TMR sensors in smartphones and camera modules, ultra-thin QFN packages have been developed to meet and replace the needs of subsequent high-performance products.

[0003] The back of the frame of ultra-thin QFN package products has a carrier plate for the frame. This carrier plate is usually quite thin and needs to be manually removed before cutting the package. Due to the excessive adhesion between the lead pads of the frame and the surface of the carrier plate, lead pads often detach during removal. Summary of the Invention

[0004] To address the existing problems, this utility model provides a flat, leadless package frame structure, comprising:

[0005] Lead frame;

[0006] A support plate disposed on the back of the lead frame;

[0007] The lead frame includes several lead frame units, each lead frame unit including a base island and lead pads separately arranged around the base island, and the lead pads located at at least four corners are connected to the adjacent lead pads of the adjacent lead frame units.

[0008] As an optional implementation, the support plate is a stainless steel plate.

[0009] As an optional implementation, the thickness of the stainless steel plate is 0.15 mm.

[0010] As an alternative implementation, adjacent lead pads corresponding to adjacent lead frame units located in the same row or column are connected by ribs.

[0011] As an alternative implementation, the corner lead pads are connected to the adjacent lead pads corresponding to the adjacent lead frame units in the same row and column.

[0012] As an alternative implementation, the connecting rib has a bridge-shaped structure, and the width of the middle part of the connecting rib is smaller than the width of the two ends of the connecting rib near the lead pad.

[0013] As an optional implementation, the packaging frame structure is a square QFN packaging frame structure, with connecting ribs between the four lead pads located at the four corners and the corresponding lead pads of adjacent lead frame units.

[0014] As an optional implementation, the packaging frame structure is a rectangular DFN packaging frame structure, with connecting ribs between the four lead pads located at the four corners and the corresponding lead pads of adjacent lead frame units.

[0015] As an alternative implementation, the remaining lead pads on both sides are connected to the corresponding lead pads of the adjacent lead frame unit by connecting ribs.

[0016] As an alternative implementation, the connecting rib is formed together with the lead pad.

[0017] This utility model embodiment also provides a flat, leadless package structure, including:

[0018] Base Island;

[0019] Lead pads are located at the four corners of the base island;

[0020] The chip is located on the front of the base island, and the chip is connected to the lead pads via leads;

[0021] A molding compound located on the front of the base island and covering the chip, leads, and lead pads.

[0022] The outer side of one or both sides of the lead pad is exposed from the side of the encapsulation layer.

[0023] Beneficial effects:

[0024] This invention increases the connecting ribs between adjacent lead frame units, enabling adjacent lead pads to connect with each other. This allows the lead pads of two or four adjacent lead frame units to form a whole, resulting in a greater clamping force on the lead pads when tearing the steel plate, thus preventing the lead pads from falling off when tearing the stainless steel plate. Attached Figure Description

[0025] Figure 1 This is a side view schematic diagram of the fabrication process of a flat, leadless package structure in the prior art;

[0026] Figure 2 This is a top view of a flat, leadless package structure in the prior art;

[0027] Figure 3 This is a schematic diagram of lead pad detachment in a flat, leadless package structure in the prior art;

[0028] Figure 4 This is a top view schematic diagram of a flat, leadless package frame according to an embodiment of the present invention;

[0029] Figure 5 This is a top view schematic diagram of a flat, leadless package frame according to another embodiment of the present invention.

[0030] Figure 6 This is a side view of the flat, leadless packaging frame of this utility model. Detailed Implementation

[0031] To enhance understanding of this invention, the present invention will be described in detail below with reference to embodiments and accompanying drawings. These embodiments are merely illustrative of the technical solutions of this invention and do not constitute a limitation on the scope of protection of this invention.

[0032] like Figure 1 and Figure 2 As shown, Figure 1 This is a side view schematic diagram of the fabrication process of an ultrathin QFN packaging structure in the prior art. Figure 2 This is a top view of the ultra-thin QFN package structure. Each leadframe unit of the ultra-thin QFN package structure includes only a base island 40 and lead pads 20 separately arranged around the base island 40. The front of the frame is the molding compound 10, and the back of the frame has a carrier plate 30, which is usually a steel plate with a relatively thin thickness. The steel plate needs to be manually removed before the final package is cut. Figure 2 As shown, the lead pads 20 are generally located near the four vertices of the leadframe unit. Because the contact area between the lead pads and the molding compound is too small, lead pads often detach during removal, ultimately forming a structure like... Figure 3 As shown, Figure 3 The lead pad 20' at the upper left corner of the left-side package has completely detached, and the lead pad 20' at the lower right corner of the right-side package has partially detached, resulting in partial loss of lead pads. This problem seriously reduces the quality of the product.

[0033] To address the above problems, this utility model provides a flat, leadless packaging frame structure, such as... Figure 4 and Figure 6 As shown, it includes:

[0034] Lead frame;

[0035] The support plate 30 is disposed on the back of the lead frame;

[0036] The lead frame includes a plurality of lead frame units 60, each lead frame unit 60 including a base island 40 and lead pads 25 separately arranged around the base island 40, and the lead pads 25 located at least at the four corners are connected to the adjacent lead pads 25 of the adjacent lead frame units 60 by connecting ribs 26.

[0037] In this embodiment, the carrier plate 30 is a stainless steel plate with a thickness of 0.15 mm. The base island 40 of the lead frame and the lead pad 25 are directly formed on the surface of the carrier plate 30 by electroplating. After the package is formed, the carrier plate 30 is peeled off, leaving the ultra-thin lead frame and molding layer, thereby forming an ultra-thin QFN package structure.

[0038] In this embodiment, the carrier plate 30 is a stainless steel plate, which can be conveniently used to form the base island and lead pads on the stainless steel plate using electroplating process, and is also relatively easy to peel off in the subsequent peeling process.

[0039] In other embodiments, the support plate may also be other support plate structures.

[0040] In this embodiment, the flat leadless package frame structure is a QFN package (square flat leadless package) frame structure. The QFN package frame structure is square. Each lead frame unit 60 includes a base island 40 and lead pads 25 separately arranged at the four corners of the base island 40. The lead pads 25 located at the four corners are connected to the adjacent lead pads 25 of the adjacent lead frame unit 60 by connecting ribs 26.

[0041] In this embodiment, adjacent lead pads 25 corresponding to adjacent lead frame units 60 in the same column have connecting ribs 26.

[0042] The connecting rib 26 has a bridge-shaped structure. The width of the middle part of the connecting rib 26 is smaller than the width of the two ends of the connecting rib 26 near the lead pad 25, which makes it easier to disconnect the connecting rib when cutting the package later.

[0043] In this embodiment, the connecting ribs, lead pads, and base islands are formed together by an electroplating process.

[0044] In other embodiments, there may also be connecting ribs between adjacent lead pads corresponding to adjacent lead frame units in the same row.

[0045] In other embodiments, such as Figure 5As shown, the lead pads 25' located at the corners are connected by ribs 26' to the adjacent lead pads 25' of the adjacent lead frame units 60 in the same row and column, so that the four adjacent lead pads 25' at the corners of the four adjacent lead frame units 60 are connected by ribs 26', thereby connecting the adjacent lead pads to the lead pads, and the lead pads corresponding to two adjacent lead frame units or four adjacent lead frame units form a whole.

[0046] This invention increases the connecting ribs between adjacent lead frame units, enabling adjacent lead pads to connect with each other. This allows the lead pads of two or four adjacent lead frame units to form a whole, resulting in a stronger bond between the integrated lead pads and the molding compound. The clamping force of the lead pads is also greater when the steel plate is torn, preventing the lead pads from falling off when the stainless steel plate is torn.

[0047] In other embodiments, the flat leadless package frame structure is a DFN (double-sided flat leadless package) frame structure. The DFN package frame structure is rectangular, and each lead frame unit includes a base island and a plurality of lead pads located on both sides of the base island. At least the lead pads located at the four corners have connecting ribs with the adjacent lead pads corresponding to the adjacent lead frame units.

[0048] In other embodiments, the remaining lead pads on both sides of the DFN packaging frame structure are connected to the corresponding lead pads of adjacent lead frame units, so that the lead frame units in the same column are connected. By increasing the connecting ribs between adjacent lead frame units, adjacent lead pads are connected to each other, so that the lead pads corresponding to two adjacent lead frame units or four adjacent lead frame units form a whole. The bonding force between the lead pads that form a whole and the molding compound is greater, the clamping force of the lead pads is greater when the steel plate is torn off, and the force of the residual stainless steel plate is reduced.

[0049] This utility model embodiment also provides a flat, leadless package structure, such as Figure 4 , Figure 5 and Figure 6 As shown, it includes:

[0050] Base Island 40;

[0051] Lead pads 25' are located at the four corners of the base island 40;

[0052] The chip 50 is located on the front side of the base island 40, and the chip 50 is connected to the lead pad 25' via the lead 45;

[0053] A molding compound 10 is located on the front of the base island 40 and covers the chip 50, lead wire 45, and lead pad 25'.

[0054] One or both outer sides of the lead pad 25' are exposed from the side of the molding compound 10.

[0055] Although this application has been disclosed above with reference to preferred embodiments, it is not intended to limit this application. Any person skilled in the art can make possible changes and modifications to the technical solutions of this application by utilizing the methods and techniques disclosed above without departing from the spirit and scope of this application. Therefore, any simple modifications, equivalent changes and alterations made to the above embodiments based on the technical essence of this application without departing from the content of the technical solutions of this application shall fall within the protection scope of the technical solutions of this application.

Claims

1. A flat, leadless package frame structure, characterized in that, include: Lead frame; A support plate disposed on the back of the lead frame; The lead frame includes several lead frame units, each lead frame unit including a base island and lead pads separately arranged around the base island, and the lead pads located at at least four corners are connected to the adjacent lead pads of the adjacent lead frame units.

2. The flat, leadless package frame structure as described in claim 1, characterized in that, The support plate is made of stainless steel.

3. The flat, leadless package frame structure as described in claim 2, characterized in that, The thickness of the stainless steel plate is 0.15 mm.

4. The flat, leadless package frame structure as described in claim 1, characterized in that, Adjacent lead frame units located in the same row or column have connecting ribs between adjacent lead pads.

5. The flat, leadless package frame structure as described in claim 1, characterized in that, The lead pads located in the corners have connecting ribs between them and the adjacent lead pads corresponding to the adjacent lead frame units in the same row and column.

6. The flat, leadless package frame structure as described in claim 1, characterized in that, The connecting rib has a bridge-shaped structure, and the width of the middle part of the connecting rib is smaller than the width of the two ends of the connecting rib near the lead pad.

7. The flat, leadless package frame structure as described in claim 1, characterized in that, The packaging frame structure is a square QFN packaging frame structure, and the four lead pads located at the four corners are connected to the corresponding lead pads of the adjacent lead frame units by connecting ribs.

8. The flat, leadless package frame structure as described in claim 1, characterized in that, The packaging frame structure is a rectangular DFN packaging frame structure, with connecting ribs between the four lead pads located at the four corners and the corresponding lead pads of the adjacent lead frame units.

9. The flat, leadless package frame structure as described in claim 8, characterized in that, The remaining lead pads on both sides are connected to the corresponding lead pads of the adjacent lead frame unit by connecting ribs.

10. The flat, leadless package frame structure as described in claim 1, characterized in that, The connecting ribs are formed together with the lead wire pads.

11. A flat, leadless package structure, characterized in that, include: Base Island; Lead pads are located at the four corners of the base island; The chip is located on the front of the base island, and the chip is connected to the lead pads via leads; A molding compound located on the front of the base island and covering the chip, leads, and lead pads. The outer side of one or both sides of the lead pad is exposed from the side of the encapsulation layer.

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