JP2008034830A - Semiconductor device, and lead frame and its manufacturing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent bonding strength deterioration owing to poor solder wettability of a terminal when a semiconductor device is mounted on a circuit board or the like. <P>SOLUTION: A semiconductor device bonding strength with the circuit board of which is improved owing to improvement of the solder wettability of its terminal achieved by covering all or at least half of a cross-sectional area of an end portion of the terminal of the semiconductor device with a plated layer, is disclosed. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a semiconductor device formed by resin molding an element such as a semiconductor integrated circuit mounted on a lead frame, and a method for manufacturing the same.

A semiconductor device in which an element such as a semiconductor integrated circuit mounted on a lead frame is resin-molded is usually mounted on a circuit board and used. Therefore, in order to secure sufficient mounting strength between the semiconductor device and the circuit board, the junction area is increased by lengthening the terminals of the semiconductor device. Conventionally, solder wettability of the terminal cut surface of the semiconductor device has not been in a good state, but since the bonding area is large and the terminal shape itself is formed in a Z shape, not only both ends of the terminal but also the terminal heel part Since the solder wettability of the solder was good, the solder scooped up the terminals, and as a result, sufficient mounting strength was secured.
JP-A-10-223822

  If the bonding area is large, the mounting strength can be ensured, but the mounting strength on the circuit board tends to decrease as the semiconductor device is miniaturized. This is because in order to increase the mounting density, it is necessary to reduce the terminal area of the semiconductor device to be bonded to the circuit board and the electrode area on the circuit board side. Solder is mainly used when a semiconductor device is mounted on a circuit board, but the mounting strength varies greatly depending on whether or not the terminals of the semiconductor device are easily wetted with the solder. When the solder reaches the melting temperature by reflow or the like, it melts together with the plating of the terminals of the semiconductor device. At that time, it is desirable that plating is formed on the entire terminal of the semiconductor device, and a portion where the plating is not present is not wetted by the solder, so that only that portion is weakened. As the size of the semiconductor device becomes smaller, sufficient strength cannot be obtained simply by bonding between the terminals of the semiconductor device and the electrodes of the circuit board, so it is necessary to secure an area where the solder gets wet as much as possible. is there. In particular, the solder wettability of the tip of the terminal of the semiconductor device is important. This is because when the semiconductor device is mounted on the circuit board, the terminal tip is easily affected by the warp of the circuit board.

  FIG. 6 is a schematic side view showing the structure of a conventional semiconductor device. Conventionally, as shown in FIG. 6, the terminal 2 protrudes from the resin 1 and is formed. Although the terminal 2 is covered with the plating layer 3, a terminal tip exposed portion 12 is formed in the terminal tip cutting portion 10 by cutting the terminal 2. The presence of the terminal tip exposed portion 12 deteriorates the wettability of the solder material used as a bonding agent when mounted on a circuit board or the like.

  FIG. 7 shows a structural diagram of a conventional semiconductor device in the middle of a manufacturing process. As shown in FIG. 7, the terminal 2 which is also a part of the lead frame connecting the two resins 21 and 31 has a uniform thickness. When the semiconductor device having such a structure is cut into pieces, the terminal exposed portion 12 as shown in FIG. 6 is formed.

  In order to firmly bond the terminal of the semiconductor device and the electrode of the circuit board, a semiconductor device in which plating is formed on the entire terminal tip portion of the semiconductor device as a means for improving solder wettability of the terminal of the semiconductor device. As another means, a semiconductor device in which the area where the plating is not formed on the cut surface of the terminal tip of the semiconductor device is one half or less of the cross-sectional area of the terminal.

  According to the present invention, without increasing the terminal area of the semiconductor device, the solder material is melted by the heat during reflow and crawls up to the upper surface of the terminal, so that the mounting strength with the circuit board can be improved. Further, the strength against the warp of the mounted circuit board can be improved.

  Embodiments of a semiconductor device according to the present invention will be described below with reference to the drawings.

  FIG. 1 is a schematic side view showing the structure of a semiconductor device according to a first embodiment of the present invention. The semiconductor device includes a resin 1, a terminal 2, and a metal plating 3 that covers the surface of the terminal. An element such as a semiconductor integrated circuit (IC chip) is covered with a resin 1 and is normally invisible from the outside. One end of the terminal 2 is electrically joined to the semiconductor integrated circuit inside the resin 1, and the other end protrudes from the resin 1, and the protruding portion of the terminal has a shape suitable for mounting on a substrate by a mold or the like. Has been formed. A plating layer 3 is formed almost entirely on the surface of the portion where the terminal 2 is exposed to the outside of the resin 1. In the embodiment shown in FIG. 1, the plating layer 3 covers the terminal tip 4 at the end of the terminal 2 and the surface of the terminal 2 is not exposed to the outside.

  FIG. 2 is a schematic side view showing the structure of the semiconductor device according to the second embodiment of the present invention. In the embodiment shown in this figure, the terminal tip 4 of the terminal 2 has a portion covered with the plating layer 3 and a terminal tip exposed portion 5 not covered with the plating layer 3. By making the cross-sectional area of the terminal tip exposed portion 5 less than or equal to one-half of the cross-sectional area of the terminal 2, the solder material that becomes a joining member when the semiconductor device is mounted on a circuit board or the like can easily wet the plating layer, Solder crawls up the terminal tip 4 so that a strong mounting state can be formed.

  FIG. 3 shows a first embodiment of the lead frame according to the present invention. An assembly in which a plurality of semiconductor devices are arranged on one lead frame is shown. The terminals 8 of each semiconductor device are connected by a plating bar 7, and the plating bar 7 is joined at the side surface of the terminal 8. The plating bar 7 is a passage through which electricity flows when electrolytic plating is performed on the lead frame 6. As described above, the structure in which the plating bar 7 is joined to the side surface of the terminal 8 makes it possible to manufacture a semiconductor device having a structure in which the terminal tip 4 is covered with the plating layer 3 as shown in FIG.

  FIG. 4 shows a second embodiment of the lead frame according to the present invention. An assembly in which a plurality of semiconductor devices are arranged on one lead frame is shown. Here, the plating bar 9 is formed by extending the terminal 8 of each semiconductor device. The plating bar 9 is a passage through which electricity flows when electrolytic plating is performed on the lead frame 6. The portion where the plating bar 9 is joined to the terminal 8 becomes a cut surface when it is cut later, and plating is not applied. Thin and thin are desirable.

  FIG. 5 is a side view of a semiconductor device according to a second embodiment of the present invention, and shows a state in the middle of manufacture. 2 shows a state in which two adjacent semiconductor devices are connected by a lead frame. As shown in FIG. 5, in the present invention, the lead frame thin portion 11 is formed on the lead frame 2. The semiconductor device having the structure of the embodiment shown in FIG. 2 can be obtained by cutting the lead frame thin portion 11 to separate the semiconductor device.

  FIG. 8 is a side view showing the process of manufacturing a semiconductor device according to the third embodiment of the present invention, and shows a state in which two adjacent semiconductor devices are connected by a lead frame. As shown in FIG. 8, in this embodiment, the lead frame thin portion 11 is formed on the lead frame 2. The lead frame thin portion 11 is formed on the surface side on which the semiconductor device is mounted on the circuit board. By cutting the lead frame thin portion 11 and dividing the semiconductor device into pieces, the semiconductor device according to the third embodiment having the structure shown in FIG. 9 can be obtained. With such a structure, the solder printed on the circuit board easily wets the upper surface of the lead.

  The lead frame thin part 11 is formed by first processing the lead frame with a press die after extracting the lead frame into a desired shape. As the partial processing method, there are a method of forming a thin portion by etching with a chemical, a method of performing a local crushing process by pressing, and the like.

  Finally, the manufacturing process will be outlined. A semiconductor integrated circuit (IC chip) is bonded on the lead frame, and the semiconductor integrated circuit and the lead frame are connected by a wire. Thereafter, the semiconductor integrated circuit is covered with resin. The state up to here is the state shown in FIGS. Thereafter, when plating is performed, portions other than the resin are entirely covered with a plating film. Further, the lead frame is cut with a mold or the like to separate the semiconductor device.

  The semiconductor device according to the present invention can be widely used for products that are required to be small and light, such as mobile phones, notebook computers, and portable electronic devices.

1 is a schematic side view showing a first embodiment of a semiconductor device according to the present invention. It is a schematic side view which shows the 2nd Example of the semiconductor device by this invention. 1 is a schematic plan view showing a first embodiment of a lead frame according to the present invention. FIG. 6 is a schematic plan view showing a second embodiment of the lead frame according to the present invention. It is the model side view which represented the lead frame by this invention partially. It is a model side view which shows the structure of the conventional semiconductor device. It is the model side view which represented the conventional lead frame partially. It is a schematic side view which shows the Example of the semiconductor device by this invention. It is a schematic side view which shows the Example of the semiconductor device by this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Resin 2 Terminal 3 Plating layer 4 Terminal tip part 5 Terminal tip exposed part 6 Lead frame 7 Plating bar 8 Terminal 9 Plating bar 10 Terminal tip cutting part 11 Lead frame thin part 12 Terminal tip exposed part 21 Resin 31 Resin

Claims (7)

  A semiconductor device having an element covered with a resin mold and a metal terminal protruding from the resin mold, wherein the end portion of the terminal is entirely covered with solder plating.   A semiconductor device having an element covered with a resin mold and a metal terminal protruding from the resin mold, the area of the portion not covered with solder plating at the tip of the terminal is the cross-sectional area of the end face Semiconductor device that is less than half   A lead frame used for manufacturing a semiconductor device having an element covered with a resin mold and a metal terminal protruding from the resin mold, and disposed on a side surface of a portion of the terminal not covered by the resin mold The lead frame is connected to the lead frame by the plated bar.   A lead frame used for manufacturing a semiconductor device having an element covered with a resin mold and a metal terminal protruding from the resin mold, and a terminal front end surface of a portion of the terminal not covered with the resin mold Is a lead frame connected to the lead frame by a plating bar whose cross-sectional area is less than half of the cross-sectional area of the terminal.   A lead frame used for manufacturing a semiconductor device having an element covered with a resin mold and a metal terminal protruding from the resin mold, and a terminal front end surface of a portion of the terminal not covered with the resin mold Is a lead frame connected to the lead frame by a plating bar that is less than one-half of the thickness of the terminal from the surface side on which the semiconductor device is mounted on the circuit board.   In a manufacturing method of a lead frame used for manufacturing a semiconductor device having an element covered with a resin mold and a metal terminal protruding from the resin mold, a portion on which a semiconductor chip is mounted by press working and connected to a circuit board A method of manufacturing a lead frame, comprising: forming a terminal and a plating bar for plating on the terminal portion; and etching the part of the plating bar with a chemical to make it thin.   In a manufacturing method of a lead frame used for manufacturing a semiconductor device having an element covered with a resin mold and a metal terminal protruding from the resin mold, a portion on which a semiconductor chip is mounted by press working and connected to a circuit board A method of manufacturing a lead frame, comprising: forming a terminal and a plating bar for performing plating on the terminal portion; and pressing the part of the plating bar again to make it thin.

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