JP2005158778A - Manufacturing method for lead frame and for semiconductor device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a manufacturing method for a lead frame in which a projecting section formed to a lead terminal is miniaturized, and which can prevent a defective mounting by forming the height of the projecting section at a high value; and to provide the manufacturing method for a semiconductor device. <P>SOLUTION: In the semiconductor device in which the mounting-side flat surface of a sealing resin and the exposed surfaces of lead terminals exposed from the sealing resin are formed in approximately the same planes, projecting shapes having widths narrower than lead widths are formed to surfaces exposed from the sealing resin of each lead terminal, and a stand-off structure is formed by pushing a pushing-shaped jig in a lead-frame forming process or a resin sealing process. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a lead frame manufacturing method and a semiconductor device manufacturing method, and more particularly to a lead frame manufacturing method and a semiconductor device manufacturing method in which a lead terminal portion has a convex shape.

  In a semiconductor device formed by sealing only one side of the lead frame, mounting is performed by foreign matter such as dust sandwiched between the back surface of the semiconductor device (mounting side flat surface of the sealing resin part) and the mounting substrate surface during mounting. Some have adopted a stand-off structure to prevent defects.

  FIG. 5 is a diagram showing a typical prior art example in which a standoff structure is formed on a lead frame. A semiconductor device in which a mounting device flat surface 7 and a lead terminal exposed surface 8 are formed in substantially the same plane. FIG. In FIG. 5, the protrusion 12 is formed on the exposed surface of the lead terminal portion 11 of the lead frame. Reference numeral 16 denotes an island portion of the lead frame, and reference numeral 13 denotes a fine metal wire, which electrically connects the semiconductor element 15 mounted on the island portion 16 and the lead terminal portion 11. Reference numeral 14 denotes a sealing resin portion.

  As disclosed in Japanese Patent Application Laid-Open No. 11-330337, a method for forming such a protrusion 12 is formed by punching or etching a thin plate material to form a lead frame shape, In general, a desired part is press-molded using a set of concave and convex molds to form steps and protrusions. In general, the stepped portion and the protruding portion of the conventional lead terminal portion formed by the press molding method are equal to the lead width of the lead frame, and are generally formed on the entire lead width.

As another method for forming the protrusion, as disclosed in Japanese Patent Application Laid-Open No. 2001-35961, a method of forming the protrusion on a part of the back surface of the semiconductor device where one surface of the lead terminal portion is exposed. In addition, a method of forming a recess at the center of the flat back surface and inside the lead terminal portion, or a method of providing a step as a protruding portion on each end surface side of the strip-shaped lead terminal portion has been proposed. Further, as a semiconductor device that improves the mounting density on the mounting substrate and has good mountability, Japanese Patent Laid-Open No. 2000-332162 discloses a step on the back surface of the semiconductor device and a step on the lead terminal portion by etching the conductive substrate. A semiconductor device in which a portion is formed is disclosed. However, since these manufacturing methods are based on etching, there is a limit to narrowing the lead terminal portions and improving the mounting density.
Japanese Patent Laid-Open No. 11-330337 JP 2001-35961 A JP 2000-332162 A

  As described above, when foreign matters such as dust adhere to the mounting side flat surface on the back surface of the semiconductor device or between the lead terminal portion and the mounting substrate surface during mounting, they are formed on the lead terminal portion of the semiconductor device and the mounting substrate. The contacted electrode does not come into contact, resulting in poor mounting. In order to prevent such mounting defects, punching, etching, pressing with a mold, and the like were used as a method of forming protrusions and steps on the lead terminal portion. In these processing methods, protrusions and steps are used. Must be formed over the entire width of the lead terminal of the lead frame, and there is a limit to reducing the pitch of the lead terminal portion and improving the mounting density. In order to solve such problems, the present invention provides a lead frame manufacturing method and semiconductor capable of preventing mounting defects by miniaturizing the protrusions formed on the lead terminal portions and increasing the height of the protrusions. An object is to provide a method for manufacturing a device.

  In order to achieve the above object, the invention according to claim 1 is directed to a method of manufacturing a lead frame including an island part for mounting a semiconductor element and a lead terminal part electrically connected to the semiconductor element. When sealing a part of the element and the lead terminal part with resin, a convex jig provided with a protrusion is pressed to each lead terminal part exposed from the sealing resin part, and the width is wider than the lead width. The method includes a step of forming a convex shape that is narrow and protrudes toward the mounting surface side of the lead terminal portion.

  According to a second aspect of the present invention, in a method of manufacturing a semiconductor device in which a resin portion in which a semiconductor element and a lead terminal portion are sealed is formed, an island portion for mounting the semiconductor element is electrically connected to the semiconductor element. When a part of the semiconductor element and the lead terminal part is sealed with resin, a convex jig provided with a protrusion is pressed to each lead terminal part exposed from the sealing resin part. And a step of preparing a lead frame having a narrower width than the lead width and forming a convex shape protruding toward the mounting surface side of the lead terminal portion, a step of mounting the semiconductor element on the island portion, and each lead terminal A step of electrically connecting the semiconductor element and the semiconductor element, and a step of resin-sealing a part of the semiconductor element and the lead terminal part so that a convex shape of the lead terminal part is exposed. That.

  According to a third aspect of the present invention, in a method of manufacturing a semiconductor device in which a resin portion in which a semiconductor element and a lead terminal portion are sealed is formed, an island portion for mounting the semiconductor element is electrically connected to the semiconductor element. A step of preparing a lead frame having a lead terminal portion; a step of mounting the semiconductor element on the island portion; a step of electrically connecting each lead terminal portion and the semiconductor element; and the semiconductor element and the lead When a part of the terminal part is sealed with resin, each lead terminal part exposed from the sealing resin part is pressed with a convex jig provided with a protrusion so that the lead width is narrower than the lead width. After forming the convex shape protruding to the mounting surface side of the terminal portion, the lead frame is sandwiched between sealing molds, and the semiconductor element and the lead terminal portion are exposed so that the convex shape of the lead terminal portion is exposed. The section is characterized by including the step of resin encapsulation.

According to a fourth aspect of the present invention, in a method of manufacturing a semiconductor device in which a semiconductor element and a resin part in which a lead frame is sealed are formed, an island part for mounting the semiconductor element is electrically connected to the semiconductor element. A step of preparing a lead frame having a lead terminal portion; a step of mounting a semiconductor element on the island portion; a step of electrically connecting each lead terminal to the semiconductor element; and the semiconductor element and the lead terminal portion. When part of the resin is sealed with resin, the lead frame is sandwiched between sealing molds, and the semiconductor element and part of the lead terminal part are resin-sealed, and at the same time exposed from the sealing resin part. Pressing each of the lead terminal portions with a convex jig provided in the sealing mold to form a convex shape that is narrower than the lead width and protrudes toward the mounting surface side of the lead terminal portion. It is characterized in.

  The lead frame manufacturing method and the semiconductor device manufacturing method according to the present invention can be formed by forming a convex shape on the lead frame in advance or forming a convex shape on the lead frame during the resin sealing step, It can be easily created at any convenient point in the process. In addition, when the present invention is applied to a lead frame formed of a material having high malleability such as a copper alloy, the height of the convex shape with respect to the thickness of the lead frame can be made relatively large, and the height of the standoff is set. There is a lot of freedom to do.

  The lead frame and the semiconductor device according to the present invention have a stand-off structure formed by the convex shape formed on the exposed surface of the lead terminal portion, and can be mounted without any problems even if there is dust or the like at the time of mounting, eliminating mounting defects. can do. Further, if the island portion is exposed, the heat of the semiconductor device can be efficiently released from the semiconductor device. Since the convex shape is narrower than the lead width, the width of the wiring formed on the mounting board can be narrowed, and it can also be applied to a lead frame formed at a narrow pitch, enabling multiple pins and improving the mounting density. Can be made.

  Hereinafter, a method for manufacturing a lead frame and a method for manufacturing a semiconductor device according to the present invention will be described. A semiconductor device in which the mounting-side flat surface of the sealing resin portion and the exposed surface of the lead terminal portion exposed from the sealing resin portion are formed in substantially the same plane from the viewpoint of preventing mounting defects and improving the mounting density. The case of forming will be described as an example.

  First, the manufacturing method of the lead frame of the first invention will be described. In accordance with a normal lead frame manufacturing method, a lead frame including an island portion for mounting a semiconductor element, a lead terminal portion electrically connected to the semiconductor element, and the like by press working from a thin plate material made of a copper-based alloy Form. Thereafter, by using a truncated cone-shaped convex jig shown in FIG. 4, the lead terminal portion of the lead frame is pressed so that the convex shape protrudes in the direction of the mounting side when the semiconductor device is formed. Specifically, the tip diameter is 0.08 mm on a copper lead frame (including Ni: 1.8%, Si: 0.4%, Zn: 1.1%) made of a copper-based alloy having a thickness of 0.127 mm. By pressing a convex jig with a frustoconical height of 2.8 mm and a diameter of the height of 2.8 mm of 1.2 mm) with a load of 2.4 kg, the lead terminal portion has a height of 0.133 mm. Can be formed. At this time, the maximum diameter of the convex shape was about 0.15 mm. Similarly, by pressing a frustoconical convex jig having a tip diameter of 0.05 mm with a load of 2.4 kg and 3.0 kg, protrusions having a height of 0.113 mm and 0.113 mm are formed, respectively. I was able to. At this time, the maximum diameter of the convex shape was about 0.10 mm. When pressing, the lead frame was placed on a base coated with a fluororesin, and a predetermined load was applied to the convex jig from the upper surface.

  Thus, according to the present invention, the maximum diameter of the protrusion is about 0.10 mm, and a protrusion that is sufficiently smaller than the width of the lead terminal (usually about 0.35 mm) can be formed. It can also be seen that the height of the protrusion is about 0.1 mm or more, and a high standoff shape can be formed. The shape of the convex jig is not limited to the truncated cone shape, and can be variously changed such as a cone shape, a pyramid shape, a truncated pyramid shape, a cylindrical shape, a prismatic shape, a spherical shape, and the like. The material of the lead frame to be used, the load, the size of the convex jig, etc. may be appropriately selected. In addition, the number and arrangement of convex shapes formed on the lead terminal portion can be selected as appropriate, and the number and arrangement of convex portions of the convex jig can be changed according to the number and arrangement of convex shapes to be formed. You can also.

  In the above description, the case where the convex shape is formed after forming the lead frame shape by pressing the thin plate material or the like is described. However, the lead frame shape can also be formed after the convex shape is formed. .

  As described above, according to the lead frame manufacturing method of the present invention, it is possible to form a convex shape (protrusion) having a narrow width compared to the width of the lead terminal portion, and the height thereof is substantially the same as the thickness of the lead frame. Therefore, even if there is an adhering substance such as dust on the mounting substrate, it is possible to prevent the occurrence of poor connection as long as it does not adhere to the portion connected to the convex shape. Moreover, the manufacturing method is only a simple method of pressing the convex jig.

  Next, an embodiment of the second invention for forming a semiconductor device using the lead frame described in the embodiment 1 will be described. FIGS. 1A and 1B are views schematically showing a cross section and a part of the back surface of a semiconductor device formed according to the second invention of the present application. This is a case where the exposed surface 8 of the lead terminal portion 1 exposed from the stop resin portion 4 is formed on substantially the same plane. The position and number of the convex shapes 2 can be set as appropriate. For example, as shown in FIG. 2, two convex shapes 2 can be provided on the lead terminal portion 1 to ensure connection with the mounting substrate.

  Examples of the method for manufacturing a semiconductor device will be described below. First, according to the manufacturing method described in the first embodiment, a lead frame having a convex shape 2 is prepared. The semiconductor element 5 is mounted on the island part 6, and the electrode of the semiconductor element 5 and the lead terminal part 1 are electrically connected by the metal thin wire 3. Next, the lead frame is sandwiched between sealing molds, and the semiconductor element 5 and a part of the lead terminal portion 1 are sealed with a sealing resin, thereby forming the sealing resin portion 4. When the sealing mold sandwiches the lead frame, the sealing mold does not sandwich the convex shape 2 so that the convex shape formed on the lead terminal portion 1 is not deformed. Thereafter, the lead frame is cut in accordance with a normal lead cutting process, and the semiconductor device having the structure shown in FIGS. 1 and 2 can be obtained.

  In the semiconductor device formed according to the present invention, since the convex shape 2 is formed narrower and higher than the width of the lead terminal portion 1, it is difficult to be affected by the adhesion of dust and the like, and the occurrence of poor connection or the like can be prevented. . As shown in FIGS. 1 and 2, the back side (inside the sealing resin portion 4) of the lead terminal portion 1 formed with the convex shape 2 has a concave shape, and the sealing resin is injected therein. This has the effect of improving the adhesion between the sealing resin and the lead terminal portion 1. The semiconductor device having the structure shown in FIG. 2 has a shape in which the sealing resin is injected into one convex shape, but it is needless to say that the invention is not limited to this.

  Next, another embodiment of the semiconductor device manufacturing method will be described. In the above-described second embodiment, the semiconductor device is formed by using the lead frame in which the convex shape 2 is formed in advance. However, in this embodiment, the convex shape 2 is formed in the course of the manufacturing process of the semiconductor device. First, in accordance with a normal manufacturing process of a semiconductor device, a lead frame including an island portion 6, a lead terminal portion 1 and the like is prepared. At this time, no convex shape is formed on the lead frame. The semiconductor element 5 is mounted on the island part 6, and the electrode of the semiconductor element 5 and the lead terminal part 1 are electrically connected by the metal thin wire 3. Next, in order to form the convex shape 2, before the semiconductor element 5 and a part of the lead terminal portion 1 are sealed with the sealing resin, a protrusion is formed on each lead terminal portion 1 exposed from the sealing resin portion 4. The provided convex jig is pressed to form a convex shape 2 narrower than the lead width. When pressing the convex jig, as described in the first embodiment, a lead frame may be placed on a base coated with a fluororesin to form a convex shape. Thereafter, according to a normal resin sealing process, the lead frame is sandwiched between sealing molds, and the semiconductor element 5 and a part of the lead terminal portion 1 are sealed to form the sealing resin portion 4. When the sealing mold sandwiches the lead frame, the sealing mold does not sandwich the convex shape 2 so that the convex shape formed on the lead terminal portion 1 is not deformed. Thereafter, the lead frame is cut in accordance with a normal lead cutting process, and the semiconductor device having the structure shown in FIGS. 1 and 2 can be obtained.

  As described above, also in this embodiment, the convex shape 2 formed on the lead terminal portion 1 is formed narrower and higher than the width of the lead terminal portion 1, so that it is not easily affected by adhesion of dust and the like, and connection failure Etc. can be prevented. As shown in FIGS. 1 and 2, the semiconductor device formed according to the present invention has a concave shape on the back side of the lead terminal 1 on which the convex shape 2 is formed, and a sealing resin is injected into the concave shape. Thus, the adhesion between the sealing resin portion 4 and the lead terminal portion 1 is improved.

  Next, another embodiment will be described. In the embodiment described in the above-described embodiment 3, the convex shape is formed by another convex jig before the lead frame is sandwiched by the sealing mold. A jig is integrally formed. In accordance with a normal manufacturing process of a semiconductor device, a lead frame including an island portion 6 and a lead terminal portion 1 is prepared. At this time, no convex shape is formed on the lead frame. The semiconductor element 5 is mounted on the island part 6, and the electrode of the semiconductor element 5 and the lead terminal part 1 are electrically connected by the metal thin wire 3. Next, in order to perform resin sealing at the same time as forming the convex shape 2, when the semiconductor element 5 and the lead terminal portion 1 are sealed with the sealing resin, each lead terminal portion 1 exposed from the sealing resin portion 4 is formed. The lead frame is sandwiched between sealing molds provided with protrusions (convex jigs) at the abutting portions. By this clamping, a convex shape 2 is formed on the lead terminal portion 1. In accordance with a normal sealing process, a sealing resin portion 4 that seals part of the semiconductor element 5 and the lead terminal portion 1 is formed. In the following, the lead frame is cut in accordance with a normal lead cutting process, and a semiconductor device having a structure schematically showing a part of the semiconductor device in FIG. 3 can be obtained.

  In the semiconductor device shown in FIG. 3, the convex shape 2 is formed outside the sealing resin portion 4, but the convex shape 2 formed on the lead terminal portion 1 is smaller than the width of the lead terminal portion 1 as in the above embodiment. Since it is formed narrow and high, it is hardly affected by the adhesion of dust and the like, and it is possible to prevent the occurrence of poor connection.

  In the semiconductor device shown in FIG. 3, the die island portion 6 is arranged in the sealing resin portion 4. However, as shown in FIGS. 1 and 2, the die island portion 6 is the sealing resin portion 4. The semiconductor device shown in FIGS. 1 and 2 may have a structure in which the die island portion 6 is disposed in the sealing resin portion 4 as in the semiconductor device shown in FIG. May be. As shown in FIGS. 1 and 2, when the die island portion 6 is exposed from the sealing resin portion 4, the heat dissipation effect is enhanced, so this structure is selected when the semiconductor element 5 generates a large amount of heat. Good to do. Although the embodiments of the present invention have been described above, various modifications are made without departing from the spirit of the present invention, such as changing the connection between the lead terminal portion 1 and the semiconductor element 5 to another wireless method instead of the thin metal wire 3. It goes without saying that it is possible.

(A) is sectional drawing which showed typically the semiconductor device formed with the manufacturing method of the semiconductor device of this invention, (b) is explanatory drawing of the back surface. It is sectional drawing which showed typically the semiconductor device explaining another Example of this invention. It is sectional drawing which showed typically the semiconductor device explaining another Example of this invention. It is explanatory drawing of the convex jig | tool used for the Example of this invention. It is sectional drawing which showed typically the semiconductor device explaining the conventional Example.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1; Lead terminal part, 2; Convex shape, 3; Metal fine wire, 4 sealing resin part, 5; Semiconductor element, 6: Island part, 7: Mounting side flat surface, 8: Exposed surface of exposed lead terminal part

Claims (4)

In a manufacturing method of a lead frame including an island part for mounting a semiconductor element and a lead terminal part electrically connected to the semiconductor element,
When sealing a part of the semiconductor element and the lead terminal part with resin, a convex jig provided with a protrusion is pressed to each lead terminal part exposed from the sealing resin part, A method of manufacturing a lead frame, comprising a step of forming a convex shape that is narrow and protrudes toward the mounting surface side of the lead terminal portion. In the manufacturing method of the semiconductor device in which the resin portion in which the semiconductor element and the lead terminal portion are sealed is formed,
An island portion for mounting a semiconductor element, and a lead terminal portion electrically connected to the semiconductor element, and when the semiconductor element and a part of the lead terminal portion are sealed with resin, the sealing resin portion A lead frame is prepared by pressing a convex jig provided with a protrusion on each lead terminal portion exposed from the lead, and forming a convex shape that is narrower than the lead width and protrudes toward the mounting surface side of the lead terminal portion. Process,
Mounting the semiconductor element on the island part;
Electrically connecting each lead terminal portion and the semiconductor element;
And a step of resin-sealing the semiconductor element and a part of the lead terminal portion so that the convex shape of the lead terminal portion is exposed. In the manufacturing method of the semiconductor device in which the resin portion in which the semiconductor element and the lead terminal portion are sealed is formed,
A step of preparing a lead frame including an island part for mounting a semiconductor element and a lead terminal part electrically connected to the semiconductor element;
Mounting the semiconductor element on the island part;
Electrically connecting each lead terminal portion and the semiconductor element;
When sealing a part of the semiconductor element and the lead terminal part with resin, a convex jig provided with a protrusion is pressed to each lead terminal part exposed from the sealing resin part, After forming a convex shape that is narrow and protrudes toward the mounting surface side of the lead terminal portion, the lead frame is sandwiched between sealing molds so that the convex shape of the lead terminal portion is exposed. And a step of resin-sealing a part of the lead terminal portion. In a manufacturing method of a semiconductor device in which a semiconductor element and a resin portion sealing a lead frame are formed,
A step of preparing a lead frame including an island part for mounting a semiconductor element and a lead terminal part electrically connected to the semiconductor element;
Mounting a semiconductor element on the island part;
Electrically connecting each lead terminal and the semiconductor element;
When sealing the semiconductor element and a part of the lead terminal part with resin, the lead frame is sandwiched between sealing molds, and simultaneously the semiconductor element and a part of the lead terminal part are resin-sealed. A convex jig provided in the sealing mold is pressed against each lead terminal portion exposed from the sealing resin portion, and the convex width is narrower than the lead width and protrudes toward the mounting surface side of the lead terminal portion. Forming a shape, and a method for manufacturing a semiconductor device.

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