TWM641162U - Pin and lead frame - Google Patents

Abstract

An embodiment of the present disclosure provides a lead and a lead frame, the lead includes: an inner lead part, the inner lead part is suitable for connecting with a chip; an outer lead part, the outer lead part is suitable for connecting with a circuit board connection; the inner pin part and the outer pin part are connected through a bending part; the pin includes a first side away from the circuit board and a second side opposite to the first side when in use ; Wherein, the connection between the inner pin portion and the bent portion includes a first step on the first side, and the first step includes a first longitudinal wall and a first longitudinal wall connected to the first longitudinal wall On a transverse plane, the first longitudinal wall is adjacent to the inner pin portion, and the included angle between the first longitudinal wall and the first side of the inner pin portion is 70°-90°. During the packaging process of the lead frame including the pins, a larger area of the wire bonding area can be provided for the bonding of the inner pin part and the chip, so as to facilitate bonding.

Description

A pin and lead frame

The present disclosure relates to the technical field of semiconductor packaging, in particular to a pin and a lead frame.

This creation claims the priority of the Chinese patent application with the application number 202121660220.9 and the new name "a pin and lead frame" submitted to the China Patent Office on July 20, 2021, the entire contents of which are incorporated in this application by reference.

In recent years, with the rapid development of electronic technology, the requirements for reliability in semiconductor packaging have been increasing. Dual Flat No-lead Package (DFN package) is a leadless package technology for surface mount. The products packaged with DFN have the characteristics of small size, light weight and suitable for portable applications. , and the packaged structure has excellent electrical and thermal properties. Therefore, the DFN package is widely used in the package with few pins.

The DFN package includes a lead frame on which pins are arranged. In the packaging process, it is necessary to connect the inner lead part of the lead frame to the chip. However, the area of the wire bonding area of the lead portion of the lead frame used in the current DFN package is too small.

In order to solve the problems existing in the prior art, an embodiment of the present disclosure provides a pin and a lead frame, which can provide a sufficient area of the wire bonding area during chip packaging.

In order to solve the above technical problems, an embodiment of the present disclosure provides a pin, including: an inner pin part, the inner pin part is suitable for connecting with a chip; an outer pin part, and the outer pin part is suitable for connecting with a circuit board connection; the inner pin part and the outer pin part are connected through a bending part; the pin includes a first side away from the circuit board and a second side opposite to the first side when in use; Wherein, the connection between the inner pin portion and the bent portion includes a first step on the first side, and the first step includes a first longitudinal wall and a first vertical wall connected to the first longitudinal wall. In the transverse plane, the first longitudinal wall is adjacent to the inner pin portion, and the included angle between the first longitudinal wall and the first side of the inner pin portion is 70°-90°.

In some embodiments, the height of the first longitudinal wall ranges from 0.03mm to 0.20mm; the angle between the first longitudinal wall and the first transverse surface ranges from 90° to 110°.

In some embodiments, the length of the first transverse face does not exceed 0.1 mm.

In some embodiments, the first transverse surface and the bent portion are connected at the first side by a first arc.

In some embodiments, the radius of curvature of the first arc does not exceed the thickness of the pin.

In some embodiments, the junction of the outer pin portion and the bent portion includes a second step on the second side, and the second step includes a second longitudinal wall and a second longitudinal wall. The connected second transverse surface, the second longitudinal wall is adjacent to the outer pin part, and the included angle between the second longitudinal wall and the second side of the outer pin part is 70°~90° .

In some embodiments, the height of the second longitudinal wall is 0.03mm-0.20mm; the angle between the second longitudinal wall and the second transverse surface is in the range of 90°-110°.

In some embodiments, the length of the second transverse face does not exceed 0.1 mm.

In some embodiments, the second transverse surface and the bent portion are connected at the second side by a second arc.

In some embodiments, the radius of curvature of the second arc does not exceed the thickness of the pin.

Further, an embodiment of the present disclosure also provides a lead frame, including the pin as described in any one of the above embodiments.

Compared with the prior art, the technical solutions of the embodiments of the present disclosure have the following beneficial effects: The embodiments of the present disclosure provide a pin and a lead frame, and the pin is arranged between the inner pin part and the bending part by first The steps can avoid the excessively large curvature radius of the bending part caused by the lead frame molding process, thereby providing a larger area of the wire bonding area and facilitating the bonding of the lead part in the lead frame and the chip.

Further, in the embodiment of the present disclosure, the second step is provided between the outer pin portion and the bending portion, which can avoid the risk of glue overflow at the connection between the outer pin portion and the bending portion in the prior art during the injection molding process.

10: Lead frame

12: Key Island

13: wire

14: Wafer

15: Frame substrate

16: Jijima Connected Ribs

17: Base Island Steps

18: V-groove

20: Pin

201: Inner pin part

202: External pin part

203: bending part

204: The first step

2041: First longitudinal wall

2042: first transverse plane

2043: The first arc

205: The second step

2051: Second longitudinal wall

2052: second transverse plane

2053: Second arc

206: First side of circuit board

207: Second side of the board

31: upper module

32: Lower module

Other features and advantages of this creation will be better understood through the following optional embodiments described in detail in conjunction with the drawings, the same symbols in the drawings represent the same or similar components, wherein: Figure 1 is a pin formation in the prior art The schematic diagram of the process; Fig. 2 is the structural schematic diagram that a kind of lead frame is connected with chip in the prior art; Fig. 3 is a schematic diagram of the pin structure of an embodiment of the present disclosure; Fig. 4 is a schematic diagram of a partially enlarged structure of the first step of the pin in the embodiment shown in Fig. 3; Fig. 5 is a schematic diagram of the pin structure of another embodiment of the present disclosure Schematic diagram; FIG. 6 is a partially enlarged structural schematic diagram of the second step of the pin in the embodiment shown in FIG. 5; FIG. 7 is a schematic structural diagram of a lead frame according to another embodiment of the present disclosure; FIG. 8 is a schematic diagram of the embodiment shown in FIG. 7 A-A cross-sectional schematic diagram.

At present, in the process of preparing the lead frame, the pins need to be bent into a 3D shape. Please refer to FIG. 1 for details. Extruded between the lower mold part 32. Since the lead frame is a metal material, plastic deformation will occur during the molding process, and the bending portion will form an arc shape.

Then, when the lead frame 10 and the chip 14 are packaged together by the wire 13, as shown in FIG. 2, because the arc area of the bent portion of the pin 20 is too large, the area of the wire bonding area of the inner pin portion will be too small. , inconvenient bonding.

Therefore, the embodiments of the present disclosure provide a pin and a lead frame, which can provide a sufficient area of the wire bonding area for the connection between the inner pin portion of the lead frame and the chip during the chip packaging process.

In order to make the purpose, technical solutions and effects of the present disclosure clearer and more specific, the present disclosure will be further described in detail below with reference to the drawings and in combination with preferred embodiments. It should be understood that the specific embodiments described here are only used to explain the present disclosure, and are not intended to limit the protection scope of the present disclosure.

An embodiment of the present disclosure provides a lead, which is a part of a lead frame, and is used for electrically connecting a chip to a circuit board. Since the wafer and the circuit board are not on the same plane, it is necessary to perform 3D bending on the leads of the lead frame.

Please refer to Fig. 3 for details, the pin 20 includes: an inner pin part 201, which is suitable for connecting with a chip; an outer pin part 202, which is suitable for connecting with a circuit board Connection; the inner pin part 201 and the outer pin part 202 are connected by a bending part 203; the pin 20 includes a first side 206 away from the circuit board and connected to the first side 206 when in use The opposite second side 207 .

In some embodiments, the thickness of the pins ranges from 0.10 mm to 0.40 mm, and the material of the pins may be copper alloy. For example, C194 copper or C7025 copper, etc.

In the embodiment shown in FIG. 3 , the connection between the inner pin portion 201 and the bent portion 203 includes a first step 204 on the first side 206 .

The partially enlarged structural schematic diagram of the first step 204, that is, the structural schematic diagram of the part inside the dotted line frame in FIG. 3 is shown in FIG. The connected first transverse surface 2042 , the first longitudinal wall 2041 is adjacent to the inner pin portion 201 , and the first transverse surface 2042 is adjacent to the bent portion 203 .

In the above embodiment, the first step 204 of the inner pin part 201 can ensure that the bending degree between the inner pin part 201 and the bending part 203 does not change, and the wire bonding can be increased. The area of the region facilitates the bonding of the inner pin part 201 and the wafer.

In some embodiments, the height of the first longitudinal wall may be 0.03 mm to 0.20 mm, and the angle between the first longitudinal wall and the first side of the inner pin portion may range from 70° to 90°. °.

In some embodiments, the length of the first transverse plane is no more than 0.1 mm, and the angle between the first longitudinal wall and the first transverse plane may range from 90° to 110°.

In the embodiment shown in FIG. 4 , the first transverse surface 2042 is connected to the bent portion 203 at the first side 206 via a first arc 2043 .

In some embodiments, the radius of curvature of the first arc does not exceed the thickness of the pin.

In some embodiments, referring to FIG. 5 for details, the connection between the outer pin portion 202 and the bent portion 203 includes a second step 205 on the second side 207 .

The partial structural schematic diagram of the second step 205, that is, the structural schematic diagram of the part inside the dotted line frame in FIG. 5 is shown in FIG. , the second longitudinal wall 2051 is adjacent to the outer pin portion 202 , and the second transverse surface 2052 is adjacent to the bent portion 203 .

In the above embodiment, the second step 205 of the outer pin portion 202 can make the lead frame close to the circuit without changing the bending degree between the outer pin portion 202 and the bending portion 203 One side of the plate, that is, the second side 207 is very close to a plane. During the sealing injection molding, the outer pin portion 202 can be closely attached to the injection molding lower mold surface, so as to reduce the risk of leakage of the sealing resin.

In some embodiments, the height of the second longitudinal wall is 0.03mm~0.20mm, and the angle range between the second longitudinal wall and the second side of the outer pin part can be 70°~90° .

In some embodiments, the length of the second transverse plane is no more than 0.1 mm, and the angle between the second longitudinal wall and the second transverse plane may range from 90° to 110°.

In the embodiment shown in FIG. 6 , the second transverse surface 2052 is connected to the bent portion 203 at the second side 207 via a second arc 2053 .

In some embodiments, the radius of curvature of the second arc does not exceed the thickness of the pin.

The present disclosure also provides a lead frame, including the pin described in any one of the foregoing embodiments.

As a specific embodiment, as shown in FIG. 7 , the lead frame 10 includes pins 20 adapted to provide electrical paths for the chip and the circuit board; and a base island 12 adapted to provide mechanical support for the chip. Specifically, the base island 12 is a convex structure, and by setting a base island step 17 on the side of the base island 12 away from the wafer, the area of the side of the base island 12 away from the circuit board is larger than that of the base island 12. The area near the side of the circuit board, the base island step 17 is suitable for preventing the sealing resin from overflowing during sealing and covering the side of the base island 12 close to the circuit board; a V-shaped groove is also provided on the base island 12 18. The V-shaped groove 18 is suitable for preventing chip solder from overflowing and climbing to the side of the base island 12 close to the circuit board. The base island 12 is connected to the frame substrate 15 through two base island ribs 16 . The pins 20 of the lead frame 10 include an inner pin part and an outer pin part, and the inner pin part is suitable for being connected to the chip through a wire when the chip is packaged; the outer pin part is suitable for completing the package The package body of the process is connected to the circuit board by solder.

Wherein, the inner pin portion 201 is provided with a first step 204, and the outer pin portion 202 is provided with a second step 205. Please refer to FIG. 8 for details. FIG. 8 shows that in the embodiment shown in FIG. The structural schematic diagram of the section A-A, that is, the structural schematic diagrams of the first step 204 and the second step 205 .

The above-mentioned embodiments have disclosed the technical content and technical characteristics of the present disclosure, and the descriptions are more specific and detailed, but the descriptions of the above-mentioned embodiments are illustrative and not restrictive. Under the concept of the present disclosure, ordinary people in the field Skilled persons can make various changes and improvements to the above-mentioned disclosed ideas, but all of them belong to the protection scope of the present disclosure. Therefore, the protection scope of the present disclosure is determined by the claims.

20: Pin

201: Inner pin part

202: External pin part

203: bending part

204: The first step

206: First side of circuit board

207: Second side of the board

Claims (11)

A pin, characterized in that it includes: an inner pin part, the inner pin part is suitable for connecting with a chip; an outer pin part, and the outer pin part is suitable for connecting with a circuit board; the inner pin part is suitable for connecting with a circuit board; The portion and the outer pin portion are connected by a bending portion; the pin includes a first side away from the circuit board and a second side opposite to the first side when in use; wherein the inner pin The junction of the bent portion and the bent portion includes a first step on the first side, the first step includes a first longitudinal wall and a first transverse face connected to the first longitudinal wall, the first The longitudinal wall is adjacent to the inner pin portion, and the included angle between the first longitudinal wall and the first side of the inner pin portion is 70°-90°. The pin according to claim 1, wherein the height of the first longitudinal wall is 0.03mm~0.20mm; the angle between the first longitudinal wall and the first transverse surface is 90°~110° °. The lead according to claim 1, wherein the length of the first lateral surface does not exceed 0.1mm. The lead according to claim 1, wherein the first lateral surface and the bent portion are connected on the first side by a first arc. The lead according to claim 4, wherein the radius of curvature of the first arc does not exceed the thickness of the lead. The pin according to claim 1, wherein the junction of the outer pin portion and the bent portion includes a second step on the second side, and the second step includes a second longitudinal wall and The second transverse surface connected to the second longitudinal wall, the second longitudinal wall is adjacent to the outer pin portion, and the angle range between the second longitudinal wall and the second side of the outer pin portion 70°~90°. The pin as claimed in item 6, wherein the height of the second longitudinal wall The degree is 0.03mm~0.20mm; the angle range between the second longitudinal wall and the second transverse surface is 90°~110°. The lead according to claim 6, wherein the length of the second lateral surface is no more than 0.1mm. The lead according to claim 6, wherein the second lateral surface and the bent portion are connected at the second side by a second arc. The lead according to claim 9, wherein the radius of curvature of the second arc does not exceed the thickness of the lead. A lead frame, comprising the lead according to any one of claims 1 to 10.

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