JP2006237289A - Lead frame structure and its manufacturing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a lead frame structure where lead frame main bodies formed of inner leads and outer leads extending from the inner leads are attached for multiple faces, and occurrence of bend of the lead frame main bodies is prevented. <P>SOLUTION: In the lead frame structure, the lead frame main bodies 10 formed of the inner leads and the outer leads extending from the inner leads are attached for a plurality of faces, and they are held by frames 20y and 20x in a linking bridge 21. In the lead frame structure where a reinforcing part 30 or 30a is disposed in the frame 20y and the frame 20x, the reinforcing part 30 or 30a is formed by bending a reinforcing piece 31 or 31a from a bending part. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a lead frame structure in which a lead frame main body used in a semiconductor integrated circuit device or the like is multifaceted, and more particularly to a leadframe structure in which a reinforcing portion is provided on a frame on which the leadframe main body is faced.

  A lead frame used in a semiconductor integrated circuit device or the like is manufactured using a metal thin plate as a raw material by a photo etching method or a punching method using a mold. When manufacturing a lead frame using a photo-etching method, in order to increase the manufacturing efficiency of the lead frame, it is common to manufacture the lead frame body on a single sheet or a long strip metal plate. Yes.

  On the other hand, in order to increase the efficiency of mounting semiconductor chips on the lead frame body, semiconductor device manufacturers that mount semiconductor chips on the lead frame body use a matrix of lead frame bodies from a multi-sided lead frame in which conventional lead frame bodies are arranged in a single row. The number of framed lead frame structures arranged in a shape has increased.

FIG. 7 shows an example of a lead frame structure in which the lead frame main body is multi-faced in a single row, and FIG. 8 shows an example of a lead frame structure with a frame in which the lead frame main body is multi-faced in a matrix.
A lead frame 500 with a frame shown in FIG. 7 is an example in which a lead frame main body 10 composed of an inner lead and an outer lead extending from the inner lead is provided in four rows in a single row. The lead frame body 10 is structured to be separated and not dropped during the manufacturing process.
A lead frame 600 with a frame shown in FIG. 8 is an example in which a lead frame main body 10 composed of inner leads and outer leads extending from the inner leads is twelve faces arranged in a matrix. The lead frame body 10 is structured to be separated and not dropped during the manufacturing process.

Currently, the lead frame has a thin plate thickness and tends to have many pins. For example, in a lead frame called a layer for ceramic packages, the package size is large, the number of pins is increased from 200 pins to 300 pins or more, and the plate thickness is as thin as about 100 μm to 150 μm. .
For this reason, the lead frame main body 10 of the lead frame structure 600 with a frame shown in the example of FIG. 8 has a thin plate thickness and a low strength, and thus is easily deformed such as bending even when a slight force is applied ( For example, see Patent Document 1.)

However, the lead frame structure with a frame in which the lead frame main body is arranged in a matrix shape makes it easy for the lead frame main body to be bent during handling even in the mounting and assembly process of the semiconductor package due to the increase in size of the lead frame main body. .
If the lead frame main body is bent after wire bonding of the semiconductor chip to the inner lead of the lead frame main body, stress is applied to the Au wire, leading to a serious defect such as disconnection or short circuit.
Therefore, it has been necessary to take measures to prevent the deflection of the lead frame body in the multi-faced lead frame.
Japanese Patent Laid-Open No. 9-232497

  The present invention has been devised in view of the above problems, and in a lead frame structure in which a lead frame main body comprising an inner lead and an outer lead extending from the inner lead is multifaceted, the lead that does not cause deflection of the lead frame main body. An object is to provide a frame structure.

  In order to achieve the above object, according to the first aspect of the present invention, in claim 1, a lead frame main body comprising an inner lead and an outer lead extending from the inner lead is provided with a plurality of surfaces and held by a frame by a connecting bridge. The lead frame structure is a lead frame structure characterized in that a reinforcing portion is provided on the frame.

  According to a second aspect of the present invention, in the lead frame structure according to the first aspect, the reinforcing portion is formed by bending a reinforcing piece from the bent portion.

  According to a third aspect of the present invention, the reinforcing piece is manufactured at the same time as the lead frame main body, the connecting bridge, and the frame are formed, and the reinforcing piece is bent from a bent portion to form the reinforcing portion. The method of manufacturing a lead frame structure according to claim 1 or 2.

  The lead according to claim 3 or 4, wherein the reinforcing portion is formed by bending the reinforcing piece when the tip of the inner lead is cut and / or when the die pad is down-set. This is a method for manufacturing a frame structure.

  Since the lead frame structure of the present invention is provided with a reinforcing portion at a predetermined position of the frame, even if the lead frame structure receives a force such as bending when handling the mounting / assembling process of the semiconductor chip, It is difficult to bend, and the assembly failure rate can be reduced without applying stress to the Au wire after mounting and assembly of the semiconductor chip.

An embodiment of a lead frame structure and a manufacturing method thereof according to the present invention will be described.
FIG. 1A is a schematic plan view of a lead frame structure 100 showing an embodiment of an imposition lead frame of the present invention, and FIGS. 1B and 1C show a reinforcing portion of FIG. FIG. 2A is a schematic sectional view taken along line -A ′, FIG. 2A is a schematic plan view of a lead frame structure 200 showing another embodiment of the imposition lead frame of the present invention, and FIG. c) is a schematic sectional view of the reinforcing portion of FIG. 2 (a) cut along the line AA ′, and FIG. 3 (a) is a lead frame showing another embodiment of the imposition lead frame of the present invention. 3B is a schematic plan view of the structure 300, FIG. 3B and FIG. 3C are schematic cross-sectional views of the reinforcing portion of FIG. 3A cut along the line AA ′, and FIG. FIG. 4B and FIG. 4A are schematic plan views of a lead frame structure 400 showing another embodiment of the imposition lead frame of FIG. Shows a schematic configuration sectional view of the reinforcing section line A-A ', respectively.

As shown in FIGS. 1, 2, 3 and 4, the lead frame structure according to the first aspect of the present invention has a single lead frame body 10 comprising an inner lead and an outer lead extending from the inner lead. Alternatively, it is imposed in a matrix form in a plurality of rows, connected to the frames 20x and 20y by a connecting bridge 21, and provided with reinforcing portions 30 or 30a at predetermined positions of the frames 20x and 20y.
Here, the frame 20x indicates a frame in the horizontal direction (row direction), and the frame 20y indicates a frame in the vertical direction (column direction).
As described above, by providing the reinforcing portion 30 or 30a at a predetermined position of the frame 20x and the frame 20y of the lead frame structure, a force is applied to the lead frame structure during the handling after mounting and assembly of the semiconductor chip, and the lead frame structure is bent. Even in this case, the margin between the lead frame main bodies 10 is bent, and the lead frame main body 10 is difficult to be bent. Therefore, no stress or the like is generated on the Au wire after mounting and assembling of the semiconductor chip, thereby reducing the mounting yield of the semiconductor package. Therefore, a reliable semiconductor package can be obtained.

The lead frame structure 100 of the present invention is an example in which a lead frame main body 10 composed of an inner lead and an outer lead extending from the inner lead is provided in four rows in a single row. And 20y, and a reinforcing portion 30 or 30a is provided at a predetermined position of the frame 20y.
Here, an example in which the reinforcing portion 30 or 30a is provided in one row of the two rows of frames 20y is shown as an example, and the arrangement of the reinforcing portion 30 or 30a on the frame 20y is limited to this. Instead, it can be set as appropriate depending on the thickness of the lead frame, the size of the lead frame main body 10, the number of impositions, and the like.

The lead frame structure 200 of the present invention is an example in which an inner lead and an outer lead extending from the inner lead are arranged in 8 rows in two rows. And the reinforcing portion 30 or 30a is provided at a predetermined position of the middle frame 20y among the three rows of frames 20y.
In this case, the reinforcing portion 30 or 30a is arranged on the frame 20y on the assumption that the lead frame structure is transported in the column direction by the transport rails, on the frames 20y at both ends of the lead frame structure 200. The reinforcing part 30 or 30a was not arranged.
The arrangement of the reinforcing portion 30 or 30a on the frame 20y is merely an example, and the arrangement of the reinforcing portion 30 or 30a on the frame 20y is not limited to this, and the thickness of the lead frame, the lead frame main body 10 and the like. Depending on the size, the number of impositions, etc., it can be set as appropriate.

The lead frame structure 300 of the present invention is an example in which the lead frame main body 10 composed of inner leads and outer leads extending from the inner leads is twelve arranged in a matrix in three rows. Are connected to the frames 20x and 20y, and among the four rows of frames 20y, reinforcing portions 30 or 30a are provided at predetermined positions of the middle two rows of frames 20y.
In this case, the reinforcing portion 30 or 30a is arranged on the frame 20y on the assumption that the lead frame structure is transported in the row direction by the transport rail, and the frames 20y at both ends of the lead frame structure 300 are disposed on the frames 20y. The reinforcing part 30 or 30a was not arranged.
The arrangement of the reinforcing portion 30 or 30a on the frame 20y is merely an example, and the arrangement of the reinforcing portion 30 or 30a on the frame 20y is not limited to this, and the thickness of the lead frame, the lead frame main body 10 and the like. Depending on the size, the number of impositions, etc., it can be set as appropriate.

The lead frame structure 400 of the present invention is an example in which the lead frame body 10 composed of inner leads and outer leads extending from the inner leads is arranged in 12 rows in a matrix in three rows. Are connected to the frames 20x and 20y, and in addition to the four columns 20y in the vertical (column) direction, a frame 20x in the horizontal (row) direction is disposed between the lead frame bodies 10, and the middle two columns This is an example in which reinforcing portions 30 or 30a are arranged at predetermined positions of the frame 20y and the frame 20x.
The examples of the lead frame structures 100, 200, and 300 are examples in which the lead frame main body is prevented from being bent with respect to the vertical (column) deflection of the lead frame structural body. This is a case where it is assumed that the lead frame structure will bend in the horizontal (row) direction when the size is increased.
In this case, the reinforcing portion 30 or 30a is disposed on the frame 20y, assuming that the lead frame structure is transported by the transport rail, the frames 20y at both ends of the lead frame structure 400 are provided with the reinforcing portion 30 or 30a was not placed.
Further, the arrangement of the reinforcing portion 30 or 30a on the frame 20y and the frame 20x is merely an example, and the arrangement of the reinforcing portion 30 or 30a on the frame 20y is not limited to this, and the thickness of the lead frame It can be set as appropriate depending on the size of the lead frame body 10 and the number of imposition.

A method for producing the reinforcing portion 30 or 30a according to claim 3 will be described.
5A to 5D are explanatory views showing an example of a method for producing the reinforcing portion 30. FIG.
This reinforcing portion 30 is provided with two bent reinforcing pieces 31 at predetermined positions of the frame 20y, and is an example in which the strength of the reinforcing portion 30 is enhanced.
First, as shown in FIGS. 5A and 5B, two reinforcing pieces 31 and a bent portion 32 are formed at predetermined positions on the frame 20y in the same manner as the processing method for creating the lead frame main body, the connecting bridge, and the frame. Is made.

Next, as shown in FIGS. 5C and 5D, the reinforcing piece 31 is bent from the bent portion 32 to produce the reinforcing portion 30.
As shown in claim 4, the bending of the reinforcing piece 31 can be efficiently performed by simultaneously performing the bending of the leading end of the inner lead and / or the down-setting of the die pad.
Moreover, in order to perform a bending process easily, you may make a half-cut of a dotted line or a straight line in the bending part 32 by half-etching or die pressing.
The bending angle θ of the reinforcing piece 31 can be set to an arbitrary angle, but is preferably about 90 degrees from the viewpoint of strength and convenience in laminating the lead frame structures.

The length W of the reinforcing piece 31 of the reinforcing portion 30 is preferably the same as the width Lw of the lead frame main body 10.
The height h of the reinforcing piece 31 of the reinforcing portion 30 is limited by the width of the frame 20y, but is preferably lower than the height of the die pad at the time of downset.

6A to 6D are explanatory views showing an example of a method for producing the reinforcing portion 30a.
The reinforcing portion 30a is provided with one reinforcing piece 31a bent at a predetermined position of the frame 20y. The strength of the reinforcing portion 30a is inferior to that of the reinforcing portion 30, but the strength of the reinforcing portion 30a is moderate. It is obtained and the structure of the reinforcing part is simplified.
First, as shown in FIGS. 6A and 6B, the reinforcing piece 31a and the bent portion 32 are produced at predetermined positions of the frame 20y by the same method as the processing method for producing the lead frame main body, the connecting bridge, and the frame. .

Next, as shown in FIGS. 6C and 6D, the reinforcing piece 31a is bent from the bent portion 32 to produce the reinforcing portion 30a.
As shown in claim 4, the bending of the reinforcing piece 31a can be efficiently performed by simultaneously performing the cutting of the inner lead and / or the downsetting of the die pad.
Moreover, in order to perform a bending process easily, you may make a half-cut of a dotted line or a straight line in the bending part 32 by half-etching or die pressing.
The bending angle θ of the reinforcing piece 31a can be set to an arbitrary angle, but about 90 degrees is preferable from the viewpoint of strength.

Further, the length W of the reinforcing piece 31a of the reinforcing portion 30a is preferably the same as the width Lw of the lead frame main body 10.
The height h of the reinforcing piece 31a of the reinforcing portion 30a is limited by the width of the frame 20y, but is preferably lower than the height of the die pad at the time of downset.

  As described above, the lead frame structure according to the present invention is provided with the reinforcing portions 30 or 30a at predetermined positions of the frame 20x and the frame 20y, so that a force is applied to the lead frame structure during handling after mounting and assembly of the semiconductor chip. Even when bent, the margin between the lead frame main bodies 10 is bent, and the lead frame main body 10 is difficult to be bent. Therefore, stress or the like is not generated on the Au wire after mounting and assembling of the semiconductor chip. A reliable semiconductor package can be obtained without reducing the mounting yield.

(A) is a schematic top view which shows one Example of the lead frame structure of this invention. (B) is a schematic cross-sectional view showing an embodiment of a reinforcing part obtained by cutting the reinforcing part of (a) along the line A-A ′. (C) is a schematic cross-sectional view showing another embodiment of the reinforcing portion obtained by cutting the reinforcing portion of (a) along the line A-A ′. (A) is a schematic top view which shows the other Example of the lead frame structure of this invention. (B) is a schematic cross-sectional view showing an embodiment of a reinforcing part obtained by cutting the reinforcing part of (a) along the line A-A ′. (C) is a schematic cross-sectional view showing another embodiment of the reinforcing portion obtained by cutting the reinforcing portion of (a) along the line A-A ′. (A) is a schematic top view which shows the other Example of the lead frame structure of this invention. (B) is a schematic cross-sectional view showing an embodiment of a reinforcing part obtained by cutting the reinforcing part of (a) along the line A-A ′. (C) is a schematic cross-sectional view showing another embodiment of the reinforcing portion obtained by cutting the reinforcing portion of (a) along the line A-A ′. (A) is a schematic top view which shows one Example of the lead frame structure of this invention. (B) is a schematic cross-sectional view showing an embodiment of a reinforcing part obtained by cutting the reinforcing part of (a) along the line A-A ′. (C) is a schematic cross-sectional view showing another embodiment of the reinforcing portion obtained by cutting the reinforcing portion of (a) along the line A-A ′. (A) is a schematic top view which shows one Example of the reinforcement piece of a reinforcement part. (B) is a schematic cross-sectional view showing an embodiment of a reinforcing piece obtained by cutting the reinforcing piece of (a) along the line A-A ′. (C) is a schematic top view which shows one Example of a reinforcement part. (D) is a schematic cross-sectional view showing an embodiment of a reinforcing part obtained by cutting the reinforcing part of (c) along the line A-A ′. (A) is a schematic top view which shows the other Example of the reinforcement piece of a reinforcement part. (B) is a schematic cross-sectional view showing another embodiment of the reinforcing piece obtained by cutting the reinforcing piece of (a) along the line A-A ′. (C) is a schematic top view which shows the other Example of a reinforcement part. (D) is a schematic cross-sectional view showing another embodiment of the reinforcing portion obtained by cutting the reinforcing portion of (c) along the line A-A ′. It is a schematic plan view which shows an example of the conventional lead frame structure. It is a schematic plan view which shows the other example of the conventional lead frame structure.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... Lead frame main body 20, 20x, 20y ... Frame 21 ... Connection bridge 30, 30a ... Reinforcement part 31, 31a ... Reinforcement piece 100, 200, 300, 400, 500, 600 ... Lead frame structure θ …… Bending angle h of reinforcing piece …… Height of reinforcing piece W …… Length of reinforcing piece Lw …… Width of lead frame body

Claims (4)

  A lead frame structure in which a plurality of lead frame bodies comprising inner leads and outer leads extending from the inner leads are attached to a frame by a connecting bridge, and a reinforcing portion is provided on the frame. A lead frame structure.   The lead frame structure according to claim 1, wherein the reinforcing portion is formed by bending a reinforcing piece from a bent portion.   The said reinforcing piece is produced simultaneously with preparation of the said lead frame main body, a connection bridge | bridging, and a frame, The said reinforcing piece is bend | folded from a bending part, and the said reinforcing part is formed. Manufacturing method of the lead frame structure.   5. The method of manufacturing a lead frame structure according to claim 3, wherein the reinforcing portion is formed by bending the reinforcing piece when the inner lead is cut and / or the die pad is down-set.

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