KR19980073905A - Lead Frame with Synthetic Resin Dam Bar and Manufacturing Method Thereof - Google Patents

Abstract

Disclosed is a lead frame provided with a dambar made of an insulating synthetic resin, and a manufacturing method thereof. The disclosed lead frame is characterized in that a dam bar made of an insulating synthetic resin is formed on the upper surface of the leads and intersects with the longitudinal direction of the leads. In addition, the manufacturing method includes: a pad on which a semiconductor chip is mounted, and a plurality of leads positioned around the pad and transferring a function of the semiconductor chip to an external circuit, and without a metal dam bar interconnecting the leads. Manufacturing a lead frame; And forming a dam bar made of an insulating synthetic resin on the upper surfaces of the leads of the lead frame to cross the longitudinal direction of the leads. It is preferable that an insulating synthetic resin is polyimide here. Therefore, by making it possible to manufacture a lead frame having a dam bar made of an insulating synthetic resin having the same function as a conventional dam bar of a metal material, it is possible to omit the trimming step in the semiconductor package fabrication process and to eliminate the need for a complicated trim mold. It is effective.

Description

Lead Frame with Synthetic Resin Dam Bar and Manufacturing Method Thereof

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a lead frame and a method for manufacturing the same, and more particularly, to a lead frame provided with an insulating synthetic dambar and a method for manufacturing the same.

There are two general methods for manufacturing a lead frame, which are a stamping method by press working and an etching method by etching.

The stamping method is mainly used in mass production by producing a lead frame in a predetermined shape by punching a material by a press mold apparatus, and the etching method is a chemical corrosion method by etching, which is complicated and fine shape. It is suitable for the manufacture of lead frames.

The lead frame manufactured by the above-described methods is a core component of the semiconductor package together with the wafer, and serves as a lead that transfers the function of the semiconductor chip to an external circuit, and simultaneously It serves as a supporting frame.

A structure of a conventional lead frame will be described below with reference to the drawings.

1 is a plan view showing a conventional lead frame.

The conventional lead frame is formed of a thin metal material, and as illustrated in FIG. 1, a pad 11 on which a semiconductor chip is mounted and a corner of the pad 11 are connected to connect the pad 11. An inner lead or internal lead 12 formed at a predetermined distance from each circumference of the pad 11 and the pad 11 and connected by a wire bonding with a terminal formed on the semiconductor chip. and an outer lead 14 extending from the lead 13 and the inner lead 13 and transferring an electrical signal of the semiconductor chip to an external circuit. In addition, a dambar 15 provided between the outer leads 14 is provided to prevent the molding resin from escaping out of the mold during the molding process during the semiconductor fabrication process. Since the dam bar 15 is generally formed at the time of manufacturing the lead frame by stamping or etching, the dam bar 15 has the same metal material as that of the lead frame material.

2 is a cross-sectional view of a conventional semiconductor package, in which like reference numerals denote the same components as in the above-described drawing.

As shown in FIG. 2, the semiconductor package is formed of a molding resin to protect the semiconductor chip 21 and the wire bonding wire 22 mounted on the lead frame and the pad 11 having the above-described structure from the outside. (23) For example, an epoxy molding compound (EMC) is used to mold the semiconductor chip 21 and the lead frame.

The manufacturing process of the semiconductor package includes a process of mounting the semiconductor chip 21 on the pad 11 of the lead frame, and a wire bonding process of electrically connecting the terminal formed on the semiconductor chip 21 and the inner lead 13. And a molding process and a trimming / forming process.

The trimming process is a process of cutting off the dam bar 15 provided to prevent the molding resin from escaping out of the mold mold and the molding resin escaping out of the mold mold in the molding process. Since the metal dambar 15 is formed between the outer leads 14 and the leads are electrically connected to each other by the dam bar 15, the leads are electrically cut by cutting the dam bar 15. Independence

The above-mentioned semiconductor package fabrication process is a necessary process, but in the case of trimming process, rather than a production process that adds added value to the produced product, it can be referred to as an after-treatment process. Need to be shortened. In addition, as the lead frame becomes increasingly high-pin with a large number of leads, the gap between the leads and the leads decreases, so that a mold punch for removing the dambar needs to be densely arranged. .

Accordingly, there have been attempts to apply a dambarless lead frame without a metal dambar in order to improve such a problem. However, when the lead frame without the metal dam bar is applied, a problem arises in that molding resin escapes from the mold mold and molding is impossible as described above.

As described above, in the case of applying the lead frame having the conventional metal dambar, a secondary trimming process is required in the semiconductor package manufacturing process, and it is difficult to manufacture a trimming mold punch. There is this. In addition, when a dambarless lead frame is applied, molding may be impossible.

SUMMARY OF THE INVENTION An object of the present invention is to solve the problems of the prior art as described above, and by removing a metal dam bar and forming a dam bar made of an insulating synthetic resin at a position thereof, a synthetic resin dam bar capable of eliminating a trimming process during a semiconductor package manufacturing process is provided. An object of the present invention is to provide a lead frame and a method of manufacturing the same.

1 is a plan view showing a conventional lead frame,

2 is a cross-sectional view showing a conventional semiconductor package;

3 is a partial plan view showing a lead frame having a polyimide dam bar according to a first embodiment of the present invention;

4A to 4D are cross-sectional views illustrating a polyimide dam bar forming process according to Example 1 of the present invention;

5 is a perspective view illustrating a lead frame having a groove formed on an upper surface of a body of a lead according to Embodiment 2 of the present invention;

6 is a perspective view showing a lead frame having a protrusion formed on a side of a body of a lead according to Embodiment 3 of the present invention;

7 is a perspective view showing a lead frame in which a groove is formed in the upper surface of the body of the lead according to the fourth embodiment of the present invention, and a protrusion is formed in the body side of the lead.

Explanation of symbols for the main parts of the drawings

11,31 ... Pad 13,33,53,63,73 ... Internal lead

14,34,54,64,74 ... External lead 15 ... Metal Dambar

35 ... Polyimide Dambar 36,56,66,76 ... Polyimide Tape

57,77 ... Home 68,78 ... Protrusion

In order to achieve the above object, a lead frame having a synthetic resin dam bar according to the present invention includes: a pad on which a semiconductor chip is mounted, and a plurality of leads positioned around the pad and transferring a function of the semiconductor chip to an external circuit. The lead frame according to claim 1, wherein a dam bar made of an insulating synthetic resin intersecting the longitudinal direction of the lead is formed on the upper surfaces of the leads.

Here, it is preferable that a part of the body of the leads is immersed in the dam bar.

Preferably, a groove into which a portion of the body of the dam bar enters is formed in an upper surface portion of the body of the leads in which the dam bar is formed, and the side of the body of the leads in which the dam bar is formed is spreading sideways. It is preferable that the protrusion part is formed. In particular, it is more preferable that the groove and the protrusion are formed together.

The insulating synthetic resin is preferably polyimide.

Meanwhile, in order to achieve the above object, a method of manufacturing a lead frame having a synthetic resin dam bar according to the present invention includes: (a) a pad on which a semiconductor chip is mounted and a peripheral portion of the pad, the function of which is transferred to an external circuit Fabricating a lead frame having a plurality of leads for transferring, wherein the lead frame is free of metal dam bars interconnecting the leads; And (b) forming a dam bar made of an insulating synthetic resin on the upper surfaces of the leads of the lead frame to cross the longitudinal direction of the leads.

Here, in the step (a), it is preferable to form a groove into which a part of the body of the dam bar enters in the upper surface portion of the body of the leads in which the dam bar is formed, and in the body side portion of the leads in which the dam bar is formed. It is preferable to form a protrusion for preventing the dambar from spreading laterally. In particular, it is more preferable to form the groove and the protrusion together.

In the step (b), the insulating synthetic resin tape is attached to the upper surfaces of the leads of the lead frame by crossing the lengthwise direction of the leads, and then the insulating synthetic resin tape is melted with the heat of the heater block to form insulating synthetic resin between the leads. It is desirable to form a modified dam bar.

And it is preferable that the said insulating synthetic resin is polyimide.

Therefore, it is possible to manufacture a lead frame having a dam bar made of an insulating synthetic resin having the same function as a conventional dam bar made of metal.

Hereinafter, with reference to the accompanying drawings will be described in detail a preferred embodiment of a lead frame and a manufacturing method having a synthetic resin dam bar according to the present invention.

Example 1

3 is a partial plan view showing a lead frame having an insulating synthetic resin according to the first embodiment of the present invention, preferably a polyimide dambar, and FIGS. 4a to 4b are polyimide It is sectional drawing which shows the formation process of a dam bar.

In order to implement the present invention, first, a dambarless lead frame of a metal material is manufactured. The production method of the lead frame uses a conventional stamping or etching method.

The next step is to form a dambar made of insulating synthetic resin.

The dam bar forming step is preferably by the following method.

First, an insulating synthetic resin tape is attached to an upper surface of the outer lead 34 of the lead frame. In this case, it is preferable to use an insulating polyimide tape 36 as the insulating synthetic resin tape.

The polyimide tape 36 is attached to cross the longitudinal direction of the lead. Here, the attachment position of the polyimide tape 36 is either inside or outside in contact with the boundary line or the boundary line between the inner lead 33 and the outer lead 34 positioned around each of the pads 31 shown in FIG. 3. It is possible. In particular, it is preferable that the position of the conventional dam bar is formed, that is, the outer lead 34 in contact with the boundary line.

The polyimide tape 36 is attached by a punch (not shown) provided on the top of the lead frame. 4A shows a state in which the polyimide tape 36 is attached to an upper surface of the outer lead 34. Since the polyimide tape 36 should be attached to the upper surface of the outer lead 34 with a predetermined thickness, the polyimide tape 36 maintains a predetermined distance from the bottom dead center of the punch and the upper surface of the outer lead 34. It is necessary. If the gap is too large, the polyimide tape 36 may not adhere properly to the top surface of the outer lead 34. If the gap is too small, the polyimide tape 36 may be damaged by the punch pressure. This is because the phenomenon of spreading to the side occurs without maintaining a predetermined thickness on the upper surface of the substrate.

Next, the polyimide tape 36 by melting the polyimide tape 36 attached to the upper surface of the outer lead 34 by heat of a heater block (not shown) and filling the space between the respective outer leads 34. To form (35). The heater block is generally used in the semiconductor package manufacturing process. The heater block is installed in the lower part of the lead frame, the temperature is preferably maintained at about 150 ~ 350 ℃, the heating time is appropriate about 3 ~ 4 seconds. 4B and 4C illustrate a process in which the polyimide tape 36 is melted by the heat of the heater block to fill the space between the outer leads 34. 4D shows a state in which the polyimide dam bar 35 is formed. In this way, the leads are immersed in the polyimide dam bar 35 except for the lower surface thereof.

In this case, the polyimide must have an insulating property to have electrical independence between the leads. If the fluidity is good, the polyimide dam bar 35 is more easily formed.

Therefore, according to the first embodiment, it is possible to manufacture a lead frame having a polyimide dam bar, so that the trimming process in the semiconductor package fabrication process can be omitted due to the insulation of the polyimide dam bar, and the production of a complicated trim mold. You do not need this.

Example 2

Embodiment 2 according to the present invention is an improvement over Example 1 described above.

According to Example 1, there is a possibility that an incomplete polyimide dam bar as shown in FIG. 4C is formed. The reason is that when the polyimide tape is attached with a punch, the polyimide tape may be spread on the upper surface of the outer lead by the pressing force of the punch, and the polyimide tape melted by the heat of the heater block may be formed between the outer leads. In this case, since the phenomenon of spreading sideways may occur, as a result, the polyimide may not completely fill the space between the lead and the lead, and an empty space may be formed at the lower portion.

Therefore, Example 2 is intended to prevent the problems caused by Example 1 as described above.

FIG. 5 is a perspective view illustrating a lead frame having a groove formed in an upper surface portion of a body of a lead in which a dam bar is formed according to Embodiment 2. FIG.

Embodiment 2 according to the present invention is subjected to the same steps as described in the first embodiment, that is, a lead frame manufacturing step without a metal dam bar, and a polyimide dam bar forming step.

This embodiment 2 is characterized in that in the step of manufacturing the lead frame without the metal dam bar, as shown in Figure 5 to form a groove 57 in the site to attach the insulating polyimide tape on the upper surface of the outer lead 54 will be.

The groove 57 is formed on the upper surface of the lead of the site to which the polyimide tape is to be attached, preferably on the upper surface of the outer lead 54, and the formation method is coined or half etched. Is preferred. That is, the thickness of the outer lead 54 of the polyimide tape attaching portion is thinner than the thickness of the outer lead 54 of the other portion, and the groove 57 is formed on the upper portion of the outer lead 54 by the difference in thickness. . Therefore, the groove 57 prevents the polyimide tape 56 from spreading laterally on the upper surface of the outer lead 54, and the polyimide can sufficiently fill the gap between the outer leads 54.

Example 3

Example 3 according to the present invention is another embodiment to improve the first embodiment described above, the purpose thereof is the same as in Example 2.

FIG. 6 is a perspective view illustrating a lead frame in which protrusions are formed at a side surface of a body of a lead in which a dam bar is formed according to Embodiment 3. FIG.

A characteristic of this embodiment 3 is to form the protrusions 68 on both sides of the outer lead 64 of the site where the polyimide dam bar is to be formed, as shown in FIG. .

In addition, the protrusions 68 are formed at the same time when manufacturing the lead frame by stamping or etching. Preferably, the protrusions 68 are formed on both sides of the outer lead 64 at two sides, and a polyimide dam bar is formed between the two protrusions formed at the one side. In addition, the protrusions 68 need to be electrically disconnected from each other at a predetermined interval from the protrusions of adjacent outer leads. The protrusion 68 prevents the polyimide tape 66 from melting and spreading sideways in the process of forming the polyimide dam bar, thereby completely filling the gap between the outer lead and the outer lead.

Example 4

Example 4 according to the present invention is the most preferred embodiment to improve the first embodiment described above, the purpose is the same as in Example 2.

7 is a perspective view illustrating a lead frame in which a groove is formed in an upper surface of a body of a lead in which a dam bar is formed, and a protrusion is formed in a side surface of the body of the lead in which the dam bar is formed.

This embodiment 4 is characterized in that in the step of manufacturing the lead frame without the metal dam bar, as shown in Figure 7 to form a groove 77 in the site to attach the insulating polyimide tape on the upper surface of the outer lead 74 In addition, the protrusions 78 are formed on both sides of the outer lead 74 at the portion where the polyimide dam bar is to be formed.

The formation position and formation method of the groove 77 and the protrusion are the same as in the above-described third embodiment and fourth embodiment. Accordingly, the groove 77 prevents the polyimide tape 76 from spreading laterally on the upper surface of the outer lead 74, and the polyimide tape 76 is melted by the protrusions 78 to form polyimide. In the process of forming the dam bar, the side spreading phenomenon is prevented to completely fill the gap between the outer lead and the outer lead.

As described above, according to the fourth embodiment of the present invention, it is possible to manufacture a lead frame having a more complete polyimide dam bar.

As described above, the lead frame with a synthetic resin dambar according to the present invention and a method of manufacturing the semiconductor package is produced by enabling the production of a lead frame having a dambar made of an insulating synthetic resin having the same function as a conventional dambar The trimming step in the process can be omitted, and there is an effect that the production of a complicated trimming mold is unnecessary.

Claims (14)

A lead frame comprising a pad on which a semiconductor chip is mounted and a plurality of leads positioned around the pad and transferring a function of the semiconductor chip to an external circuit, And a dam bar made of an insulating synthetic resin intersecting the longitudinal direction of the lead on the upper surfaces of the leads. The method of claim 1, A lead frame having a synthetic dam bar, characterized in that the body portion of the leads are immersed in the dam bar. The method of claim 1, Lead frame provided with a synthetic resin dam bar, characterized in that the groove is formed in the upper surface portion of the body of the lead is formed the dam bar, the body portion of the dam bar is entered. The method of claim 1, Lead frame provided with a synthetic resin dam bar, characterized in that the protrusion formed to prevent the dam bar from spreading to the side portion of the body of the leads in which the dam bar is formed. The method of claim 1, A groove is formed in the upper surface portion of the body of the leads in which the dam bar is formed, and a protrusion for preventing the dam bar from spreading sideways in the body side portion of the leads in which the dam bar is formed. Lead frame provided with a synthetic resin dambar, characterized in that formed. The method according to any one of claims 1 to 5, The insulating synthetic resin is a lead frame provided with a synthetic resin dam bar, characterized in that the polyimide. (a) fabricating a lead frame having a pad on which a semiconductor chip is mounted and a plurality of leads positioned around the pad and transferring the functions of the semiconductor chip to an external circuit, and without a metal dam bar interconnecting the leads; Doing; And (b) forming a dam bar made of an insulating synthetic resin on the upper surfaces of the leads of the lead frame by crossing the length direction of the lead. The method of claim 7, wherein In the step (a), a method for manufacturing a lead frame with a synthetic resin dam bar, characterized in that to form a groove in which a portion of the body of the dam bar enters, the upper surface portion of the body of the leads in which the dam bar is formed. The method of claim 8, The groove is a lead frame manufacturing method provided with a synthetic resin dam bar, characterized in that formed by coining or half etching. The method of claim 7, wherein In the step (a), a method for manufacturing a lead frame with a synthetic resin dam bar, characterized in that forming a protrusion for preventing the dam bar from spreading to the side of the body portion of the leads in which the dam bar is formed. The method of claim 10, The protrusions are formed on each of the two sides of the body of the lead, each of which is a lead frame manufacturing method with a synthetic resin dam bar, characterized in that the dam bar is formed therebetween. The method of claim 7, wherein A groove is formed in the upper surface portion of the body of the leads in which the dam bar is formed, and a protrusion is formed in the side surface of the body in which the dam bar is formed to prevent the dam bar from spreading sideways. Lead frame manufacturing method provided with a synthetic resin dam bar, characterized in that. The method of claim 7, wherein In the step (b), the insulating synthetic resin tape is attached to the upper surfaces of the leads of the lead frame by crossing the lengthwise direction of the leads, and then the insulating synthetic resin tape is melted with the heat of the heater block to form insulating synthetic resin between the leads. Lead frame manufacturing method provided with a synthetic dambar, characterized in that to form a dambar. The method according to any one of claims 7 to 13, The insulating synthetic resin is a lead frame manufacturing method provided with a synthetic resin dam bar, characterized in that the polyimide.