JP4356960B2 - Resin-sealed semiconductor device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention belongs to the technical field of a resin-encapsulated semiconductor device in which a semiconductor element is mounted on a lead frame and its outer periphery, in particular, the upper surface side of the semiconductor element is sealed with a mold resin.
[0002]
[Prior art]
In recent years, with the increase in the density of board mounting, there has been a demand for downsizing and thinning of semiconductor products mounted on the board. LSIs are also required to reduce the number of chips due to high integration and to reduce the size and weight of packages, and so-called CSP (Chip Size Package) is rapidly spreading. In particular, in the development of thin semiconductor products using lead frames, a single-side sealed type resin-sealed semiconductor device has been developed in which a semiconductor element is mounted on a lead frame and the mounting surface is sealed with a mold resin. Yes.
[0003]
FIG. 1 is a cross-sectional view showing an example of a resin-encapsulated semiconductor device, and FIG. 2 is a plan view showing the encapsulating resin as seen through. The resin-encapsulated semiconductor device shown in these drawings includes a semiconductor element 4 mounted on a die pad 3 supported by suspension leads 2 of a lead frame 1, electrodes on the upper surface of the semiconductor element 4, and terminals of the lead frame 1. A metal thin wire 6 that is electrically connected to the portion 5 and a sealing resin 7 that seals an outer region of the semiconductor element 4 including the upper side of the semiconductor element 4 and the lower side of the die pad 3 are provided. This resin-encapsulated semiconductor device is a non-lead type in which a so-called outer lead does not protrude and both the inner lead and the outer lead are integrated as the terminal portion 5. The lead frame 1 used is half-etched so that the die pad 3 is positioned above the terminal portion. Since there is such a step, the sealing resin 7 can be present under the die pad 3, and a thin shape is realized even if the die pad is not exposed.
[0004]
Since the non-lead type resin-encapsulated semiconductor device as described above has a small semiconductor element size, a matrix type manufactured by arranging a plurality of rows in the width direction of one frame is mainly used. And recently, due to the demand for cost reduction, it has been considered to shift from the individual molding type as shown in FIG. 3 to the batch molding type as shown in FIG.
[0005]
In the individual mold type, as shown in FIG. 3A, individual mold cavities C having a small size are provided separately in one frame F, and after molding, the mold is individually punched by a mold. The semiconductor device S shown in 3 (B) is obtained. That is, a semiconductor element is mounted on a die pad of a lead frame with silver paste or the like, wire bonding is performed, individual semiconductor elements are individually molded, and then punched as individual semiconductor devices with a mold.
[0006]
In the collective mold type, as shown in FIG. 4A, several mold cavities C having a large size are provided in one frame F, and each of the mold cavities C has a large number of semiconductors. The elements are arranged in a matrix, the semiconductor elements are molded together, and the grid leads L of each lead frame are cut with a dicing saw to obtain the semiconductor device S shown in FIG. is there. In other words, a semiconductor element is mounted on a die pad of a lead frame with silver paste or the like, and after wire bonding, a plurality of arrayed semiconductor elements are collectively molded with a predetermined cavity size and then separated by dicing. To do.
[0007]
[Problems to be solved by the invention]
In the resin-encapsulated semiconductor device described above, heat generated by the heat generated from the semiconductor element is transmitted to the suspension lead through the die pad. At this time, the suspension lead may be peeled off from the sealing resin due to the difference in thermal expansion coefficient between the metal and the resin. Therefore, in order to prevent this peeling, a shape in which a protrusion is provided in the middle of the suspension lead, or a so-called fishtail shape in which the tip of the suspension lead 2 is bifurcated as shown in FIG. In order to prevent peeling.
[0008]
FIG. 5 is a rear view showing an example of a resin-encapsulated semiconductor device. In particular, the present invention is not limited to the individual mold type having the fishtail-shaped suspension leads 2 as shown in the figure. However, in the resin-encapsulated semiconductor device, as shown in the figure, the suspension leads 2 and The space between the adjacent terminal portions 5 is the narrowest. Therefore, when the resin-encapsulated semiconductor device S is mounted on the substrate, a short circuit accident due to a solder bridge occurs between the suspension lead 2 exposed from the encapsulating resin 7 on the back surface side and the terminal portion 5 adjacent thereto. There is a problem that it is easy. Therefore, the terminal portion 5 is rounded as shown in the figure, but the area for connection becomes small, and it is difficult to etch as designed.
[0009]
The present invention has been made in view of such problems, and the object of the present invention is, in particular, an individual mold type, and a resin-sealed type that does not cause a solder short-circuit accident during mounting. It is to provide a semiconductor device.
[0010]
[Means for Solving the Problems]
In order to achieve the above object, the resin-encapsulated semiconductor device of the present invention mounts a semiconductor element on a die pad of a lead frame , performs wire bonding, and then individually molds each semiconductor element. An individual mold type resin-encapsulated semiconductor device manufactured by punching as an individual semiconductor device using a die, a semiconductor element mounted on a die pad supported by a suspension lead of a lead frame, and the semiconductor element Includes a fine metal wire that electrically connects the electrode on the upper surface and the terminal portion of the lead frame, and a fine metal wire with the terminal portion of the lead frame slightly protruding from the side surface and the lower surface of the terminal portion exposed as an external terminal e Bei a sealing resin made sealing the outer囲領region of the semiconductor element, the suspension lead is likewise the sealing resin and the terminal portion side of the lead frame And has a detecting section, when the distal end tip portion including at least the protruding portion of the suspension leads, the back surface side other than the tip portion, half etching such that the outer boundary line is located inside the space of the mold cavity are, sealing resin covering the half etching part, is characterized in that the lower surface of the tip portion is exposed.
[0011]
DETAILED DESCRIPTION OF THE INVENTION
Next, embodiments of the present invention will be described with reference to the drawings.
[0012]
FIG. 6 is a rear view showing an example of a frame used for manufacturing the resin-encapsulated semiconductor device of the present invention.
[0013]
Although one lead frame is shown in FIG. 6, actually, for example, as shown in FIG. 3A, a plurality of rows of three lead frames are arranged in one metal frame F corresponding to the mold cavity C. Has been placed. In each lead frame, the die pad 3 is supported by four suspension leads 2. Further, the suspension lead 2 has a fishtail shape, and the back surface of the suspension lead 2 is half-etched, and the portion indicated by the oblique lines in FIG. 6 is thinned. Here, the outer boundary line α of the half-etched portion of the suspension lead 2 is designed to be located inside the space of the mold cavity.
[0014]
The procedure for manufacturing a resin-encapsulated semiconductor device using the frame F is as follows. First, a semiconductor element is mounted on the die pad 3 in each lead frame of the frame F by silver paste, and wire bonding is performed between the terminal portion 5 and the electrode on the upper surface of the semiconductor element. Molding is performed using individually enclosing mold cavities, and then punched into individual semiconductor devices using a mold. In this case, the terminal portion 5 is cut by slightly punching the outside so as not to cover the mold resin.
[0015]
FIG. 7 shows the back surface of the resin-encapsulated semiconductor device thus manufactured. In this resin-encapsulated semiconductor device S, each terminal portion 5 of the lead frame slightly protrudes from the side surface of the encapsulating resin 7, and the lower surface of the terminal portion 5 is exposed as an external terminal. The suspension frame lead 2 of the lead frame has a protruding portion on the side surface of the sealing resin 7 like the terminal portion 5, and the sealing resin 7 is suspended except for the tip portion 2 a including the protruding portion. The back side of the lead 2 is covered. That is, the lower end portion 2a having a size including at least the protruding portion is exposed.
[0016]
As described above, since the back surface of the suspension lead 2 other than the tip portion 2a is thinned by being half-etched, the sealing resin enters the back surface side of the suspension lead 2 during molding, and the sealing resin as shown in FIG. 7 becomes the state which covered the lower surfaces other than the front-end | tip part 2a of the suspension lead 2. As shown in FIG. Therefore, the metal portion exposed on the back side of the semiconductor device is in a state where a sufficient interval is maintained, so that the solder does not connect the metal portion when mounted on the substrate.
[0017]
Here, if the case where all the back surfaces of the suspension leads 2 are half-etched is considered, the back surface of the suspension leads 2 is covered with the sealing resin and hidden when molded, but the portion protruding from the side surface of the sealing resin is the bottom surface. It will be floating from. Therefore, when the individual semiconductor devices are punched by the mold, as shown in FIG. 8, the protruding portions of the suspension leads 2 are lifted from the surface of the die 11, and burrs are generated when the punch 12 is cut. On the other hand, in the lead frame of FIG. 6, since the back surface is half-etched leaving the tip portion 2a of the suspension lead 2, the protrusion and the back surface of the semiconductor device become the same surface when molded, and each semiconductor device As shown in FIG. 9, the projecting portion of the suspension lead 2 does not float from the surface of the die 11, and no burrs are generated when the punch 12 is cut. In this case, when the dimension a of the tip portion 2a of the suspension lead 2 is set to 0.1 mm or more, the tip portion 2a is pressed down, so that no dropping or the like occurs during cutting.
[0018]
Usually, the lower side of the die pad 3 is also half-etched, and at the same time, the back side of the suspension lead 2 may be half-etched.
[0019]
In the above description, the case of the fishtail-shaped suspension lead has been described as an example, but it is needless to say that the present invention is not limited to this shape of suspension lead.
[0020]
【The invention's effect】
As described above, according to the present invention, semiconductor elements are mounted on a die pad of a lead frame, wire bonding is performed, individual semiconductor elements are individually molded, and then punched as individual semiconductor devices using a mold. An individual mold type resin-encapsulated semiconductor device manufactured by manufacturing a semiconductor element mounted on a die pad supported by a suspension lead of a lead frame, an electrode on the upper surface of the semiconductor element, and a terminal portion of the lead frame The enclosing region of the semiconductor element including the fine metal wires is sealed with the fine metal wires that are electrically connected to each other and the terminal portion of the lead frame slightly protruding from the side surface and the lower surface of the lead portion is exposed as an external terminal. e Bei a sealing resin is formed by, together with a protrusion on the suspension lead is likewise the sealing resin and the terminal portion side of the lead frame, hanging When the distal end portion of the tip side including at least the projecting portion of the over-de, back side other than the tip portion are half-etched such that the outer boundary line is located inside the space of the mold cavity, sealing resin covering the half etching portion, the lower surface of the distal end portion has a configuration which is exposed, to become a state of exposed metal on the back side of the semiconductor device is held a sufficient distance, at the time of substrate mounting Short circuit accidents due to solder bridges can be eliminated. Moreover, since the tip portion of the suspension lead and the back surface of the semiconductor device are the same surface, the tip portion of the suspension lead can be pressed when punching into individual semiconductor devices after molding, thus preventing the occurrence of cut burrs. be able to.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view showing an example of a resin-encapsulated semiconductor device.
2 is a plan view of the resin-encapsulated semiconductor device shown in FIG. 1. FIG.
FIG. 3 is an explanatory diagram of an individual mold type.
FIG. 4 is an explanatory view of a batch mold type.
FIG. 5 is a rear view showing an example of a resin-encapsulated semiconductor device.
FIG. 6 is a rear view showing an example of a frame used for manufacturing the resin-encapsulated semiconductor device of the present invention.
7 is a rear view of a resin-encapsulated semiconductor device manufactured using the frame shown in FIG. 6. FIG.
FIG. 8 is an explanatory view showing a state in which burrs are generated when each semiconductor device is punched by a mold.
FIG. 9 is an explanatory view showing a state in which burrs are not generated when each semiconductor device is punched by a mold.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Lead frame 2 Hanging lead 3 Die pad 4 Semiconductor element 5 Terminal part 6 Metal fine wire 7 Sealing resin 10 Lead frame 11 Die 12 Punch C Mold cavity F Frame L Grid lead S Semiconductor device

Claims (1)

A semiconductor element is mounted on a die pad of a lead frame, wire bonding is performed, individual semiconductor elements are individually molded, and then punched out as individual semiconductor devices using a mold. A stationary semiconductor device, a semiconductor element mounted on a die pad supported by a suspension lead of a lead frame, and a thin metal wire electrically connecting an electrode on the upper surface of the semiconductor element and a terminal portion of the lead frame , with the lower surface of the terminal portion is exposed as external terminals with the terminal portion of the lead frame protrudes slightly from the side, e Bei a sealing resin made sealing the outer囲領region of the semiconductor device including the thin metal wires at least a collision in conjunction with, the suspension leads having protrusions hanging leads similarly the sealing resin and the terminal portion side of the lead frame The tip side including the parts when the distal end portion, the rear surface side, the outer boundary lines are half-etched so as to lie inside the space of the mold cavity, the sealing resin is half-etched portion thereof other than the distal end portion A resin-encapsulated semiconductor device characterized in that the lower surface of the tip portion is exposed.

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