JP2587632B2 - Semiconductor device - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor device, and more particularly, to a method for fixing a semiconductor pellet on a lead frame having a specific shape without a die pad without using a die bonding adhesive. The present invention relates to a semiconductor device using a die pad tape having a specific structure.

[Conventional technology]

In a conventional semiconductor device, as shown in FIG. 2, a die bonding adhesive layer 5 is formed on a die pad of a lead frame including a die pad 1, a lead 2 and a support bar 3 as shown in FIGS. A semiconductor pellet 4 is placed via the intermediary, and is integrated by a sealing resin 8 together with a bonding wire 6 connecting an electrode 7 and a lead 2 formed on the pellet.

In this case, the die pad constituting the lead frame is
It is necessary to change the size and shape of the semiconductor pellet to correspond to the size and shape of the semiconductor pellet, which is extremely diverse, and accordingly, the size and shape of the lead must be changed. Changing the design of the lead frame in accordance with a wide variety of semiconductor pellets in this way requires the production of many types of lead frame dies, which increases the cost of the dies and, consequently, the cost of the lead frame. There are many.

In addition, since the die bonding adhesive for fixing the semiconductor pellet is usually applied in the form of a conductive paste containing silver as a component, there is a problem in assembling the semiconductor device, handling the semiconductor device, or preserving the paste itself. there were.

In addition, since the back surface of the die pad has poor adhesion and sealing properties with the sealing resin, it is easy for moisture from the outside that has entered from the interface between the lead and the sealing resin to accumulate, which is a problem when the semiconductor device is surface-mounted on a circuit board. During the heat treatment in the soldering process, internal stress is easily generated in the sealing resin and the like due to rapid expansion of water due to this, and the semiconductor pellet and the sealing are caused by the stress generated by the difference in the thermal expansion coefficient between the semiconductor pellet and the die pad. There is a problem that cracks occur in the resin.

[Problems to be solved by the invention]

The present invention has been made in view of the above circumstances, and aims to unify the lead frame of a semiconductor device having the same number of leads, and when assembling a semiconductor device to accommodate semiconductor pellets having various sizes and shapes. An object of the present invention is to provide a highly reliable semiconductor device while eliminating complexity.

[Means for solving the problem]

An outline of the present invention constitutes a lead frame in a semiconductor device formed by sealing a semiconductor pellet mounted on a die pad tape having a size covering a lead frame from which a die pad is eliminated and a lead end of the lead frame. A desired number of leads among the leads protrude into the die pad gap, and the protruding tip of the lead is configured to have a larger area than other leads, or the protruding tip of the lead is formed of another lead. The die pad tape is bonded to the tip portion to form a bridge portion, and the die pad tape includes a support, a first adhesive layer for fixing a semiconductor pellet provided on one surface thereof to the support, and a second adhesive layer. A semiconductor device comprising a surface and a second adhesive layer for fixing a support to leads.

 Next, the present invention will be described with reference to the drawings.

An example of the semiconductor device of the present invention is as shown in the cross-sectional view of FIG. 3, and the semiconductor pellet 4 is directly bonded and fixed to the first adhesive layer 11 on the upper surface of the support 10 of the die pad tape,
On the other hand, the second adhesive layer 12 on the lower surface of the support is adhered onto the lead 2 of the lead frame, and is integrated with the bonding wire 6 connecting the electrode 7 and the lead 2 with the sealing resin 8. . Reference numeral 9 denotes a void.

In this case, the sealing material of the semiconductor device of the present invention is not limited to the sealing with a resin, but may be a sealing type or a sealing type, for example.

The die pad tape according to the present invention is applied to a lead frame having a structure excluding a conventional die pad as shown in FIG. 4 or FIG. Is formed in an arbitrary size in accordance with the shape and size of the device, and is mounted by bonding.

In the drawing, 2 is a lead, 9 is a void, 13 is a lead protruding into the void, 14a is a wide portion, and 14b is a bridge.

[Action]

In the present invention, as shown in FIG. 4, by forming the leading end of the lead to have a larger area than the other leads, a stable flatness with respect to the die pad tape can be obtained with a minimum number of leads, which is suitable for the tape. It can exhibit its function as a support material.

Also, as shown in FIG. 5, by forming a cross-linking portion by connecting the tips of the protruding leads to form a so-called connecting lead, it is mechanically stable and has good flatness and an assembly line of the apparatus. Not only is it suitable for vibration resistance in the process of, but also when the lead is used as a power supply lead, the connection lead stabilizes the voltage,
In addition, when a semiconductor element requiring a back bias is mounted, there is an operational effect that is advantageous for stabilizing the element.

(Adhesive) Regarding the adhesive used on both sides of the support,
The first adhesive layer is for fixing the semiconductor pellet to the support, and the second adhesive layer is for fixing the support to the lead, and is made of a heat-resistant epoxy resin, polyimide resin, or the like. It is formed by coating in a semi-cured (B stage) state so as to have a coating thickness of 5050 μm, preferably 20-30 μm.

In this case, in actual assembling, the tape is first adhered to the lead surface while being thermally cured with a second adhesive layer. However, at this stage, the first adhesive layer is not completely cured. Next, the pellet is adhered to the first adhesive layer, and the first and second adhesive layers are simultaneously completely cured.
Therefore, it is desirable that the curing temperature of the first adhesive layer be higher than the curing temperature of the second adhesive layer.

[Support] The support is, for example, 10 to 150 μm in thickness, preferably 25 to 75 μm.
Heat-resistant or semi-cured epoxy glass cloth, epoxy-polyimide glass cloth, glass impregnated with heat-resistant film such as polyimide, polyetherimide, polyphenylene sulfide, polyether ether ketone, etc. A heat-resistant tape such as a BT resin glass cloth impregnated with a bismaleimide triazine resin (BT resin) is used.

〔Example〕

Example 1 A coating solution having the following composition was dried as a first adhesive layer on one surface of a support made of a polyimide resin film ("UPILEX S" manufactured by Ube Industries, Ltd.) having a thickness of 50 [mu] m to have a coating thickness of 20 [mu] m.
And dried.

Epoxy resin (“Epicoat 1001” manufactured by Yuka Shell Epoxy) 80% MEK solution ……… 120 parts by weight Dicyandiamide (Wako Pure Chemical Industries) ……… 10 parts by weight Polyamide resin (“# 6900” manufactured by Henkel Hakusui) 20% methanol / toluene (1: 1) solution 100 parts by weight Next, a coating solution having the following composition was applied as a second adhesive layer and dried so that the coating thickness after drying was 20 μm.

Epoxy resin (EOCN-102, Nippon Kayaku) 10 parts by weight Polyester resin (KA-1036, Arakawa Chemical) 50 parts by weight Imidazole-based curing agent (2PZ, Shikoku Chemicals) 10 100 parts by weight Methyl ethyl ketone 100 parts by weight The obtained die pad tape is cut into a desired size, and a lead frame formed by punching an iron-based metal plate such as a Kovar plate having a shape shown in FIG. Then, the semiconductor devices as shown in FIG. 3 were sequentially assembled.

When the reliability of the obtained semiconductor device was checked by a mounting test, no current leakage of the adhesive layer was observed, and stable adhesiveness was confirmed. In addition, a reliable semiconductor device having good wire bondability could be formed.

Example 2 A support made of a 50 μm thick polyimide resin film (“UPILEX S” manufactured by Ube Industries, Ltd.)
Polyurethane resin ("Chisso Rex
372 "70% by weight of a 43% solution of dimethylformamide / methyl ethyl ketone = 2/1 in Chisso Corporation and 30 parts by weight of a 20% solution of phenol novolak epoxy resin (" EPPN-201 ", Nippon Kayaku) in methyl ethyl ketone Was applied under a heating condition of 120 ° C. for 5 minutes so as to be in a semi-cured state, so that a coating thickness after drying was 40 μm, and was heated and dried.

Next, the second adhesive layer used in Example 1 was provided to prepare a die pad tape of the present invention.

After the obtained die pad tape was cut into a desired size and then bonded to a lead frame shown in FIG. 4 (b) by heating with an adhesive layer, the semiconductor device shown in FIG. 3 was assembled.

When the reliability of the obtained semiconductor device was checked by a mounting test, no current leakage of the adhesive layer was observed, and stable adhesiveness was confirmed. In addition, a reliable semiconductor device having good wire bondability was able to be constructed.

〔The invention's effect〕

Since the present invention has the above-described configuration, the die pad tape can be arbitrarily cut in accordance with the shape and dimensions of the semiconductor pellet and supplied to the semiconductor pellet mounting portion of the lead frame, thereby improving the efficiency in designing and manufacturing the pellet and the lead frame. This is effective for cost reduction, and the paste-type die bonding adhesive is not required, so that the workability in assembling the apparatus is good.

In addition, because the adhesiveness between the adhesive layer and the sealing resin constituting the die pad tape is good, there is no fear that cracks may occur in the sealing resin due to rapid expansion of moisture, and the coefficient of thermal expansion between the semiconductor pellet and the die pad tape. Since the stress caused by the difference between the leads is small, there is no occurrence of cracks in the semiconductor pellet. Further, the tip of the desired lead among the leads is protruded into the die pad gap to increase the area of the tip or to bridge the area. Because the part is provided, the support of the die pad tape is stable, and there is no equivalent to the gap between the tip of the lead and the die pad as in the conventional lead frame, so the bonding wire is It is possible to provide an extremely reliable semiconductor device which can be expected to have an effect of not flowing or cutting.

[Brief description of the drawings]

1 and 2 are a perspective view and a sectional view showing an example of a conventional semiconductor device. FIG. 3 is a sectional view showing an embodiment of the present invention.
4 and 5 are front views showing examples of a lead frame used in the present invention. 2 ... lead, 4 ... semiconductor pellet, 6 ... bonding wire, 8 ... sealing material, 9 ... die pad gap, 10 ... support, 11 ... first adhesive layer, 12 ... second 2, adhesive layer.

 ──────────────────────────────────────────────────続 き Continuing from the front page (72) Atsushi Koshimura, Inventor 3-1, Yosobamachi, Shizuoka City Inside the Technical Research Laboratory of Hamakawa Paper Mill Co., Ltd. (72) Inventor Tan Matsushita 3-1, Yosobamachi, Shizuoka City Shares (72) Inventor, Masaki Tsushima, 3-1 Yosoba-cho, Shizuoka-shi In-house Technical Research Laboratory, (72) Inventor, Mitsuharu Shimizu 1216, Gorihara Kusama, Nakano-shi Takaoka Kogyo Co., Ltd. Inside the Shinko Electric Industrial Co., Ltd. Takaoka Factory (72) Inventor Hideo Ariga 1216 Kusama Gorihara Nakano City Takaoka Industrial Park In the Shinoka Electric Industrial Co., Ltd. Takaoka Factory (56) References JP-A-60-167454 (JP) JP-A-57-97659 (JP, A) JP-A-60-68639 (JP, A) JP-A-61-12095 (JP, A) JP-A-63-216365 (JP, A) 57-83753 (J , U)

Claims (2)

(57) [Claims] 1. A semiconductor device comprising: a lead frame from which a die pad has been removed; and a semiconductor device comprising a semiconductor pellet mounted on a die pad tape having a size including a tip of a lead of the lead frame. A desired number of leads among the leads to be formed protrude into the die pad gap, and the protruding tips have a larger area than the other leads, and the die pad tape has a support and one surface thereof. A first adhesive layer for fixing the semiconductor pellet provided on the substrate to the support, and a second adhesive layer for fixing the support provided on the other surface to the lead. Semiconductor device. 2. A semiconductor device comprising: a lead frame from which a die pad is removed; and a semiconductor device in which a semiconductor pellet mounted on a die pad tape having a size covering a lead end of the lead frame is covered. The desired number of leads among the leads to be projected into the die pad gap, and the tips of the protruded leads are combined with the tips of the other leads to form a bridge, and the die pad tape has a support, It is composed of a first adhesive layer provided on one surface for fixing the semiconductor pellet to the support, and a second adhesive layer provided on the other surface for fixing the support to the lead. A semiconductor device characterized by the above-mentioned.