JP2633514B2 - Semiconductor device and manufacturing method thereof - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a technique effective when applied to electrical connection of pellets in a resin-sealed semiconductor device.

2. Description of the Related Art In a so-called resin-encapsulated semiconductor device, as the size of a pellet increases, the dimension between a package side end and a tab serving as a pellet mounting portion tends to be further reduced. This is due to the fact that although the size of the pellet is large, the size of the package for accommodating the pellet cannot be enlarged because the size of the package is standardized.

As a result, of the leads which are external terminals,
In the case of so-called short leads, in which the length embedded in the resin forming the package is short due to its structure, the adhesive strength is further reduced, so that it is easy to fall out of the package, and the lead is peeled off when the lead is bent. Is likely to occur.

[0004] Therefore, the present inventors have found that the reliability of a semiconductor device is liable to be lowered, such as poor electrical conduction or reduced moisture resistance.

[0005] As for the resin-encapsulated semiconductor device,
Published by the Japan Industrial Research Association on January 15, 1980, edited by the Japan Microelectronics Association, "IC packaging technology" P
149-P150.

An object of the present invention is to significantly increase the bonding strength between a resin and a lead of a resin-encapsulated semiconductor device, especially a semiconductor device on which a large pellet is mounted. It is to provide the technology which can do.

[0007] The above and other objects and novel features of the present invention will become apparent from the description of the present specification and the accompanying drawings.

[Summary of the Invention] Of the inventions disclosed in the present application, the outline of a representative one will be briefly described as follows.

That is, a semiconductor device according to the present invention comprises a square semiconductor pellet having a circuit forming surface on which a semiconductor integrated circuit is formed and a non-circuit forming surface opposite thereto, and a row formed on the circuit forming surface. A plurality of bonding pads, a plurality of leads extending on both sides of the same row of the bonding pads, and being partially adhered to the circuit forming surface; and respective internal lead portions of the plurality of leads. The semiconductor device includes a plurality of bonding wires that connect the plurality of bonding pads in the same row, and a package resin portion that seals an internal lead of each of the semiconductor pellet and the plurality of leads.
Further, the method of manufacturing a semiconductor device according to the present invention has a circuit forming surface on which a semiconductor integrated circuit is formed and a non-circuit forming surface opposite thereto, and a plurality of A step of preparing a rectangular semiconductor pellet on which bonding pads are arranged; a step of preparing a lead frame having a plurality of leads; and the plurality of leads extending on both sides of the same row of the bonding pads of the semiconductor pellet. Connecting the semiconductor pellet and the plurality of leads on the circuit formation surface of the semiconductor pellet, and electrically connecting the internal lead portions of the plurality of leads and the plurality of bonding pads in the same row. Connecting the semiconductor pellet, and sealing the internal lead of each of the plurality of leads. .

As described above, since the plurality of leads extend on both sides of the plurality of bonding pads arranged in a row on the circuit forming surface, the internal leads are adhered to the circuit forming surface. Adhesion between the lead and the package forming resin can be greatly improved.

FIG. 1 is a cross-sectional view of a semiconductor device according to a first embodiment of the present invention, taken along the line II in FIG. 2. FIG. It is a top view showing a relation.

The semiconductor device of Reference Example 1 is a so-called resin-sealed type semiconductor device. In other words, a semiconductor pellet (hereinafter, referred to as a pellet) 1 to be mounted is a resin (hereinafter, also referred to as a package resin) such as an epoxy resin which forms a package 3 together with an internal lead which is a part of a lead 2 as an external terminal. 4), the external leads outside the package of the leads 2 are bent downward near the side ends of the package 3.

In a resin-encapsulated semiconductor device, a pellet is usually mounted on a tab, which is a mounting substrate having a size similar to that of the pellet, and a bonding pad, which is an electrode of the pellet, is provided around the tab. It is electrically connected to the inner ends of the arranged leads via wires.

However, in the semiconductor device of Reference Example 1, the pellet 1 is connected to the lead extending along the back surface of the pellet 1, that is, the non-circuit-forming main surface which is the surface on which the semiconductor integrated circuit is not formed. Is attached to the insulating sheet 5 made of a polyimide resin via an adhesive 6, and there is no tab as a pellet attaching portion.

As shown in FIG. 2, the positional relationship between the pellets 1 and the leads 2 is on the side of the pellet side where bonding pads are not arranged and formed (hereinafter also referred to as the side where no bonding pads are formed). The internal lead of the lead 2a on which the external lead is arranged extends along the non-circuit-forming main surface of the pellet 1 and its tip 2b extends to a position beyond the pellet side on which the bonding pad 7 is arranged and formed. Has been extended. An insulating sheet 5 is adhered on these leads 2a, and the pellet 1 is attached to the upper surface of the insulating sheet 5 with its non-circuit-forming main surface facing down.

Incidentally, the place where the lead 2a is buried is, in a usual resin-sealed semiconductor device, the lead buried in the package resin, that is, the internal lead extends from the package side end to the vicinity of the tab. This is a place where so-called short leads are provided, which can secure only a very limited length.

Normally, short leads have a problem that they have a small adhesive area with the package resin and thus have a low tensile strength and are easily detached from the package. This situation is serious with the recent increase in size of pellets.

However, in the semiconductor device of Reference Example 1, the leads 2a provided at locations corresponding to the short leads are used.
Since the internal lead has an extremely long shape, the bonding strength with the package resin 4 can be greatly improved. Therefore, even when large pellets are mounted,
It is possible to effectively prevent peeling at the lead interface which occurs at the time of bending and forming an external lead, thereby improving the moisture resistance of the semiconductor device. In addition, since the insulating sheet 5 is firmly adhered to the lead 2a, the lead 2a has an extremely large tensile strength.

Although the leads 2a are interposed through the insulating sheet 5, they are attached to the non-circuit-forming main surface of the pellet 1, so that the heat generated in the pellet during operation is dissipated directly to the outside of the package through the leads. It is possible.

Further, the electrical connection between the pellet 1 and the lead 2a is achieved by wire bonding between the bonding pad 7a and the tip 2b extending near the pellet side close to the bonding pad 7a. Can be shortened. Therefore, it is possible to prevent the occurrence of the short circuit of the wire, and to reduce the amount of the wire 8 to be used.

In the semiconductor device of Reference Example 1, a lead frame having a predetermined lead shape is formed, an insulating sheet 5 is bonded to a predetermined portion of the internal lead, and a pellet 1 is bonded to the insulating sheet 5 with an adhesive 6. Then, wire bonding is performed between the bonding pad 7 of the pellet 1 and the bonding portion of the lead, and thereafter the semiconductor device is easily completed through the same manufacturing process as a normal resin-encapsulated semiconductor device.
In this case, the insulating sheet 5 also plays a role of reinforcing the lead frame.

Incidentally, the bonding portion of the lead can be formed by depositing, for example, gold on a part of the lead by a partial plating method.

FIG. 3 shows a partial plan view of the lead frame to which the insulating sheet 5 is adhered from the vicinity of the tie bar 9 to the inside thereof. In the case of the semiconductor device of Reference Example 1, since the insulating sheet 5 itself functions as a mask, only a mask having an opening indicated by a two-dot chain line in FIG. Since the partial plating can be performed, the bonding portion can be easily formed.

Although FIG. 3 shows a mask in which a gap is formed only in the length direction, a mask having an opening in which a gap is formed in the direction of the tie bar 9 can be used. The leads can be easily partially plated. This makes it easy to manufacture a semiconductor device on which a pellet having bonding pads formed around the four sides thereof is mounted.

[Embodiment 2] FIG. 4 is a plan view showing a relationship between a pellet and a lead in a semiconductor device according to Embodiment 2 of the present invention.

The semiconductor device of Reference Example 2 is substantially the same as the semiconductor device of Reference Example 1. However, the difference is that the insulating sheet 5 is not used and the tab 10 smaller than the pellet 1 exists.

That is, in the semiconductor device of Reference Example 2, the pellet 1 is attached via an adhesive to the internal lead and the tab of the lead 2a in which the external lead is arranged on the side of the pellet where no bonding pad is formed. Is what it is.

In the case of the reference example 2, since the insulating sheet 5 is not interposed therebetween, the heat radiation from the pellet 1 is direct, the thermal resistance is much lower than that of the reference example 1, and the reliability is higher accordingly. Things. Further, since the tab 10 is provided, the pellet mounting strength is also ensured. FIG.
FIG. 4 is a partial cross-sectional view showing a state of electrical connection between the pellet 1 and the tip of the lead 2 on the VV cross section in FIG. 4, and a recess 2c is formed in the tip 2b of the lead 2a.

That is, when the pellet 1 is attached with the adhesive 11, the adhesive 11 flows out and the bonding portion 12
In some cases, the bonding pad 7 of the pellet 1 and the bonding portion 12 cannot be bonded with the wire 8 because the surface of the bonding pad 7 is soiled. The concave portion 2c is provided as a dam for the adhesive 11 flowing out in order to prevent such a situation from occurring.

FIG. 6 is a sectional view showing a semiconductor device according to an embodiment of the present invention, and FIG. 7 is a plan view showing a relationship between a pellet and a lead in the semiconductor device.

The semiconductor device of this embodiment differs from the first or second embodiment in that the internal leads extend along the circuit forming surface of the pellet.

That is, as shown in FIG. 6, the pellet 1 is attached to the insulating sheet 5 made of a polyimide resin adhered to the back surface of the internal lead via the adhesive 6 on the circuit forming surface.

As shown in FIG. 7, an insulating sheet 5 having a size that does not cover the bonding pads is bonded to the circuit forming surface of the pellet 1 and the upper surface of the insulating sheet 5 is formed on the side of the pellet where no bonding pad is formed. The internal lead of the lead 2a having the external lead on the side extends. The internal leads of each of the leads 2a are bonded to the insulating sheet 5a such that the tips thereof are located in front of the bonding pads.

As shown in FIG. 7, the bonding pads 7 are arranged on the circuit
a extend on both sides of the row of the bonding pads 7, and the internal leads of the leads 2 a
Through a wire 8.

In the semiconductor device of this embodiment, since the internal leads are adhered to the surface of the pellet 1 on which the circuit is formed, the heat dissipation is better than that of the first embodiment.

Further, since the insulating sheet 5 is a polyimide resin having excellent α-ray resistance and covers the circuit forming surface, the improvement of the reliability for α-rays is achieved.

In this embodiment, since the tip of the lead 2a is located inside the bonding pad 7, the positional relationship is opposite to that of the first embodiment.
The bonding direction is also reversed. However, the bonding distances are almost the same.

[Effects] Of the inventions disclosed in the present application, effects obtained by typical ones will be briefly described as follows.

(1) In a resin-encapsulated semiconductor device, by bonding an internal lead to a circuit forming surface of a pellet to be mounted, it is possible to greatly improve the adhesive force between the internal lead and a package forming resin. Therefore, even when a large pellet is mounted, the lead can be prevented from coming off from the package forming resin.

(2) For the same reason as in the above (1), it is possible to prevent the peeling of the bonding surface between the external lead and the package-forming resin during the bending of the external lead.

(3) According to the above (1) and (2), a highly reliable semiconductor device excellent in moisture resistance can be provided even in a semiconductor device in which a large pellet is mounted in a small package.

(4) By attaching the internal leads to the circuit forming surface of the pellet, heat generated in the circuit during operation can be dissipated more directly and efficiently to the outside through the leads.

(5) By extending the leads on both sides of the row of bonding pads, the interval between the internal leads adjacent in the width direction can be increased, and the bonding operation can be performed reliably. On the other hand, if the lead spacing is the same, a large number of leads can be arranged in a predetermined space.

[Field of Application] Although the invention made by the present inventors has been specifically described based on the embodiments, the present invention is not limited to the above-described embodiments, and various modifications may be made without departing from the scope of the invention. Needless to say, it can be changed.

For example, in the embodiment, the first
Although the inner lead is attached to the main surface using an insulating sheet, the present invention is not limited to this, and all or a part of the inner lead may be extended near the circuit forming surface. .

In the embodiment, only the lead on the side of the pellet corresponding to the position of the so-called short lead is shown. However, the present invention is not limited to this. May be used. Further, the insulating sheet is not limited to polyimide, but may be silicone rubber. In order to enhance heat dissipation, an adhesive or an insulating sheet may contain a thermally conductive filler such as silicon carbide (SiC) powder. it can.

In the above description, the case where the invention made by the present inventor is applied to a so-called DIP type semiconductor device, which is a field of use as a background, has been described. However, the invention is not limited to this. If the package is formed by resin sealing, it is an effective technique applicable to semiconductor devices having various types of package structures such as a flat package.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of a semiconductor device according to a first embodiment of the present invention, taken along line II in FIG. 2;

FIG. 2 is a plan view showing a relationship between a pellet and a lead of the semiconductor device of Reference Example 1.

FIG. 3 is a partial plan view showing a lead frame applied to the semiconductor device of Reference Example 1 in a plating step.

FIG. 4 is a plan view showing a relationship between a pellet and a lead in a semiconductor device which is Embodiment 2 of the present invention.

5 shows the internal structure of the semiconductor device of Reference Example 2, and FIG.
5 is a sectional view taken along line VV in FIG.

FIG. 6 shows a semiconductor device according to an embodiment of the present invention;
FIG. 8 is a sectional view taken along line VI-VI in FIG. 7.

FIG. 7 is a plan view illustrating a relationship between a pellet and a lead of the semiconductor device of the present embodiment.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Semiconductor pellet 2, 2a Lead 2b Tip 2c Depression 3 Package 4 Resin 5 Insulating sheet 6 Adhesive 7, 7a Bonding pad 8 Wire 9 Tie bar 10 Tab 11 Adhesive 12 Bonding part

Continuing from the front page (72) Inventor Hiroshi Tachi 5-20-1, Josuihonmachi, Kodaira-shi, Tokyo Inside Hitachi Ultra-SII Engineering Co., Ltd. (72) Inventor Hiroshi Ozaki In Kodaira-shi, Tokyo 5-20-1, Mizumotocho Hitachi Ultra-SII Engineering Co., Ltd. (72) Inventor Hiroharu Otsuka 1450 Kamisumihoncho, Kodaira-shi, Tokyo Hitachi, Ltd. Device Development Center (72) Inventor Michiaki Furukawa 1450, Josuihoncho, Kodaira-shi, Tokyo Inside the Device Development Center, Hitachi, Ltd. (72) Inventor Yasuyuki Yamazaki 1450, Josuihoncho, Kodaira-shi, Tokyo Inside the Device Development Center, Hitachi, Ltd. References JP-A-59-92556 (JP, A) JP-A-52-40062 (JP, A) JP-A-57-113456 (JP, U)

Claims (2)

(57) [Claims] 1. A rectangular semiconductor pellet having a circuit formation surface on which a semiconductor integrated circuit is formed and a non-circuit formation surface opposite thereto, and a plurality of bondings arranged in rows on the circuit formation surface and the pad, when extending on both sides of the same column of the bonding pad DOO
A plurality of leads that are partially adhered to the circuit forming surface; and the same internal lead portions as the plurality of leads.
A semiconductor device, comprising: a plurality of bonding wires for connecting a plurality of bonding pads in a row; and a package resin portion for sealing an internal lead portion of each of the semiconductor pellet and the plurality of leads. 2. A circuit forming surface on which a semiconductor integrated circuit is formed.
And a non-circuit forming surface opposite thereto, and
A plurality of bonding pads arranged in a row on the circuit forming surface;
Of preparing a rectangular semiconductor pellet on which is arranged
Preparing a lead frame having a plurality of leads
And the same row of the bonding pads of the semiconductor pellet
The semiconductor so that the plurality of leads extend on both sides of the semiconductor
On the circuit forming surface of the pellet, the semiconductor pellet and
Connecting the plurality of leads and the internal lead portions of the plurality of leads and the same
Electrical connection between multiple rows of bonding pads
And the inside of each of the semiconductor pellet and the plurality of leads.
And sealing the lead portion.
A method for manufacturing a conductor device.