JP2006339273A - Method of manufacturing lead frame and method of manufacturing semiconductor device using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method of manufacturing a lead frame that has high precision and can suppress the occurrence of resin flash. <P>SOLUTION: At least one portion of the lead frame 8 is formed on a metal original plate transferred in the same direction with a prescribed pitch along with a pilot hole 5 used as a positioning hole in a manufacturing process. Then, the pilot hole 5 is utilized as the positioning hole for completing the lead frame 8. The pilot hole 5 is utilized as the positioning hole for forming an envelope 9 in the completed lead frame 8. The pilot hole used in a process for completing the lead frame is the same as that used in a process for forming the envelope. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a lead frame manufacturing method and a semiconductor device manufacturing method using the same, and more particularly to a lead frame forming method including an envelope and a semiconductor device manufacturing method using the same.

  When a lead frame is manufactured by punching a metal original plate using a punching die, it is generally manufactured using a progressive press method. The progressive feed press method is a method in which dies are arranged at equal intervals and press working is performed while the metal original plate 104 is sequentially transferred.

  FIG. 9 is a view showing an example of a punching die 102 used for manufacturing a conventional lead frame manufactured by using a progressive press method. The punching die 102 includes four punching dies (punching dies 102a to 102d). FIG. 10 is a cross-sectional view at each stage in the process of manufacturing a conventional lead frame.

  The punching dies 102a to 102d are arranged at intervals that match the movement pitch of the metal original plate. Then, the metal original plate 104 is transferred in the same direction (right direction in FIG. 10) at a predetermined pitch, and the metal original plate 104 is repeatedly punched in the order of the punching dies 102a, 102b, 102c, and 102d.

  In the step shown in FIG. 10A, the pilot hole 131 is punched into the metal original plate 104 by the punching die 102a. The pilot hole 131 is a positioning hole used for alignment when forming the lead frame, and is formed in a region to be an outer frame portion of the lead frame.

  Next, in the step shown in FIG. 10B, the metal original plate 104 is transferred by 1 pitch, and the position to be pressed is determined based on the pilot holes 131. Then, at the determined position, the pilot hole 132 is press punched into the metal original plate 104 by the punching die 2. The pilot hole 131 is a positioning hole used for positioning in assembling a semiconductor device, such as forming an envelope, which will be described later, or mounting a semiconductor element. The pilot hole 132 is formed in a region adjacent to the region where the pilot hole 131 is formed in the step shown in FIG.

  In the step shown in FIG. 10C, the metal original plate 104 is transferred by 1 pitch, and the position to be pressed is determined based on the pilot hole 131. Then, at the determined position, a hole 106 for forming a lead portion (hereinafter referred to as a lead portion forming hole 106) is press punched into the metal original plate 104 by a punching die 102c. At this time, punching by the punching dies 102a and 102b is also performed at the same time.

  In the step shown in FIG. 10 (d), the metal original plate 104 is moved by 1 pitch, and the position to be pressed is determined based on the pilot holes 131. Then, at the determined position, the lead part forming hole 107 (hereinafter referred to as the lead part forming hole 107) is press punched into the metal original plate 104 by the punching die 4. At this time, punching with the punching dies 102a to 102c is also performed at the same time.

  10 (a) to 10 (d), as shown in FIG. 10 (e), the punching region located at the right end of the metal original plate 104 has a pilot hole 131, a pilot hole 132, a lead portion forming hole 106, And the lead portion forming hole 107 is formed, and the lead frame 108 for use in assembling the semiconductor device is completed. With the above punching process, one cycle of punching is completed.

  In the step shown in FIG. 10 (f), the metal base plate 104 is moved by one pitch, and the position at which the lead frame 108 is fixed to the envelope forming mold is determined based on the pilot holes 132. Then, an envelope 109 that surrounds each of the lead portions formed at a plurality of locations is formed at the determined position. Through this process, the lead frame 110 with the envelope for mounting the semiconductor chip is completed. Also in this step, punching with the punching dies 102a to 102d is performed at the same time. In this punching process, a punching position is determined with reference to the pilot hole 131.

  In general, a mold having a width dimension matching a lead portion for assembling a semiconductor element is formed in a mold used for forming an envelope. And the position which inserts a lead part in the cavity of a metal mold | die is determined using the pilot hole for envelope formation. Thus, the envelope can be completed by injection molding with the resin in a state where the gap between the cavity and the lead portion is minimized.

In the above description, the punching dies 102a to 102d are assumed to be independent dies. In the conventional method, it is possible to avoid punching the adjacent punched parts at the same time as much as possible. It is common to perform punching. This is to maintain the uniformity of the strength of the metal original plate and the balance of the pressing pressure. However, in recent years, in order to achieve high dimensional accuracy, a method of simultaneously punching adjacent punching processes at close intervals has also been performed (for example, Patent Document 1).
Japanese Patent Laid-Open No. 10-154784

  However, in any of the manufacturing methods, the pilot hole used when assembling the semiconductor device and the pilot hole used when forming the lead frame are separately formed by press punching. The position accuracy is not stable. Therefore, since the gap between the lead part and the mold groove part used for injection molding changes, rubbing and resin burrs are generated in the lead part and the mold groove part.

  SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a lead frame manufacturing method and a semiconductor device manufacturing method using the same that can suppress the generation of resin burrs with high accuracy.

  The present invention is a method of manufacturing a lead frame, the step of forming at least a part of the lead frame together with pilot holes used as positioning holes in the manufacturing process on a metal original plate that is transferred in the same direction at a predetermined pitch; A step of completing the lead frame by using a pilot hole as a positioning hole to complete a lead frame; and a step of using the pilot hole as a positioning hole and forming an envelope in the completed lead frame. The pilot hole used in the above and the pilot hole used in the step of forming the envelope are the same hole.

  The present invention also relates to a method for manufacturing a semiconductor device, the step of forming at least a part of a lead frame on a metal original plate that is transferred in the same direction at a predetermined pitch together with pilot holes used as positioning holes in the manufacturing process. And a step of completing the lead frame by using the pilot hole as a positioning hole, a step of forming an envelope in the completed lead frame by using the pilot hole as a positioning hole, and a semiconductor element in the envelope A pilot hole used in the process of completing the lead frame, including the step of electrically connecting the semiconductor element and the lead formed on the lead frame and the step of filling the envelope with resin. And the pilot hole used in the step of forming the envelope is the same hole.

  For example, the semiconductor element may be a light emitting semiconductor element, and the resin may be a transmissive resin.

  ADVANTAGE OF THE INVENTION According to this invention, the manufacturing method of a lead frame which can suppress generation | occurrence | production of a resin burr with high precision, and the manufacturing method of a semiconductor device using the same are provided.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

(First embodiment)
FIG. 1 is a view showing an example of a punching die 1 used for manufacturing a lead frame according to the first embodiment of the present invention. The lead frame according to the present embodiment is manufactured using a progressive press method. The punching die 1 shown in FIG. 1 includes two punching dies (cutting dies 2 and 3). The punching dies 2 and 3 are arranged at intervals that match the movement pitch of the metal original plate.

  2A to 2D are cross-sectional views at each stage in the process of manufacturing the lead frame and the semiconductor device using the lead frame according to the present embodiment. Hereinafter, a method for manufacturing a resin-encapsulated semiconductor device according to an embodiment of the present invention will be described with reference to FIG.

  First, in the step shown in FIG. 2A, the metal original plate 4 is transferred in the same direction (right direction in FIG. 2) at a predetermined pitch, and the metal original plate 4 is punched by the punching dies 2 and 3. The punching die 2 forms a pilot hole 5 and a lead portion forming hole 6 (hereinafter referred to as a lead portion forming hole 6). Here, one of the major features of the present invention is that the pilot hole 5 is used for both alignment during press working and alignment during assembly of the semiconductor device.

  Next, in the step shown in FIG. 2 (b), the metal original plate 4 is transferred by 1 pitch, and the position to be pressed is determined based on the pilot holes 5. Then, at the determined position, the stamping dies 2 and 3 are used to press punch the metal original plate 4. The punching die 2 forms a pilot hole 5 and a lead portion forming hole 6, and the punching die 3 forms a lead portion forming hole 7 (hereinafter referred to as a lead portion forming hole 7). The position where the punching process is performed by the punching die 3 matches the position where the punching process is performed by the punching die 2 in the step 2 (a).

  2A and 2B, a pilot hole 5, a lead portion forming hole 6, and a lead portion forming hole 7 are formed as shown in FIG. A lead frame 8 for use in assembling the semiconductor device is completed in the punched region located. With the above punching process, one cycle of punching is completed.

  In the step shown in FIG. 2D, the metal base plate 4 is moved by 1 pitch, and the position for fixing the lead frame 8 to the injection mold for forming the envelope is determined based on the pilot hole 5. . Then, at the determined position, the envelope 9 surrounding each of the lead portions formed at a plurality of locations is injection-molded. By this process, the lead frame 10 with the envelope for mounting the semiconductor chip is completed. Also in this step, punching by the punching dies 2 and 3 may be performed simultaneously.

  FIG. 3 is a view showing the lead frame 10 formed through the steps shown in FIG. In FIG. 3, the lead frame 10 is formed with an envelope 9 in which tip portions of four external leads 11 are led out.

  FIG. 4 is a view showing an optical semiconductor device assembled using the lead frame 10 shown in FIG. In the semiconductor element assembly area of the lead frame 10, that is, in the area surrounded by the envelope 9, one electrode of the semiconductor element 12 bonded to the external lead 11 a and the external lead 11 b are connected via the fine metal wires 13. Connect electrically. For example, when the semiconductor device is a light emitting diode, the semiconductor element 12 is a light emitting diode chip. Thereafter, the inside of the envelope 9 is filled with resin to complete the semiconductor device. In addition, when the semiconductor element 12 is a light emitting diode chip, the filled resin is a translucent resin.

  FIG. 5 is a view showing an X-X ′ cross section of the semiconductor device shown in FIG. 4. One electrode of the semiconductor element 12 bonded to the external lead 11a and the external lead 11b are electrically connected through a thin metal wire 13. The envelope 9 is filled with a resin 14.

  As described above, according to the present embodiment, the pilot hole is punched simultaneously with the lead portion forming hole for forming the lead frame. Thereby, the lead frame excellent in dimensional stability can be manufactured compared with the case where the lead portion forming hole and the pilot hole are processed in separate processes. Therefore, it is possible to manufacture a semiconductor device that is highly accurate and does not generate resin burrs.

  In addition, since the pilot holes used for alignment when assembling the semiconductor device are the same as the pilot holes used for alignment during press processing, it is possible to align the mold with high accuracy when forming the envelope. it can. This makes it possible to perform injection molding in a state where the gap between the mold used in the resin molding process and the lead frame is kept to a minimum, so that the external lead portion is formed from the boundary surface between the sealing resin and the lead frame. A thin residue (resin burr) of the sealing resin generated along the side can be suppressed. Furthermore, according to the present embodiment, since a lead frame having excellent dimensional stability can be manufactured, it is more effective in suppressing the generation of resin burrs.

  In the manufacture of conventional semiconductor devices, resin burrs are generated. Therefore, after the step of molding the envelope, a step of removing resin burrs such as sandblast, water jet, air jet and the like is indispensable. However, according to this embodiment, since generation | occurrence | production of the resin burr | flash can be suppressed, the above-mentioned resin burr removal process can be made unnecessary. Therefore, the number of manufacturing steps of the semiconductor device can be reduced and the production efficiency can be improved.

  In the present embodiment, the pilot hole and the lead portion forming hole are simultaneously punched. Thereby, since the punching process can be concentrated, it is possible to reduce the size of the mold.

  Furthermore, according to the present embodiment, a lead frame having excellent dimensional stability can be manufactured, and further, positioning accuracy during resin sealing can be improved, so that the friction between the mold groove and the external lead can be improved. Can be suppressed.

  FIG. 6 is a graph showing the number of repairs per month of an injection mold for forming the envelope. In the graph shown in FIG. 6, the vertical axis represents the number of repairs of the mold, and the horizontal axis represents the month in which the number of repairs of the mold was counted. The number of mold repairs per month was counted for four months from October 2004 to January 2005. The average number of times the mold is used per month is about 100,000 shots. October and November indicate the number of times the mold is repaired when a semiconductor manufacturing apparatus is manufactured using a conventional manufacturing method. On the other hand, December and January of the following year indicate the number of times the mold is repaired when the semiconductor manufacturing apparatus is manufactured using the manufacturing method according to the present embodiment. From the graph shown in FIG. 6, it can be seen that the number of repairs of the mold is reduced to about one fifth. Therefore, according to the present embodiment, it is possible to improve the maintainability in addition to the reduction of the material cost for manufacturing and repairing the mold.

(Second Embodiment)
In the first embodiment, the pilot hole used when forming the lead frame and the pilot hole used when assembling the semiconductor device are the same hole. Here, these holes may not be the same hole. The second embodiment is characterized in that pilot holes used when forming the lead frame and pilot holes used when assembling the semiconductor device are different holes.

  FIG. 7 is a view showing an example of a punching die 21 used for manufacturing a lead frame according to an embodiment of the present invention. The punching die 21 shown in FIG. 7 includes two punching dies (punching dies 22 and 23). The difference from the first embodiment is that the punch hole used for forming the lead frame and the pilot hole used for assembling the semiconductor device are formed in the die 22.

  FIG. 8 is a cross-sectional view at each stage in the process of manufacturing the resin-encapsulated semiconductor device according to the second embodiment of the present invention.

  First, in the process shown in FIG. 8A, the metal original plate 24 is transferred in the same direction (right direction in FIG. 8) at a predetermined pitch, and the metal original plate 24 is punched by the punching dies 22 and 23. With the punching die 22, the pilot hole 25 a, the pilot hole 25 b and the lead portion forming hole 26 are punched into the metal original plate 104. The pilot hole 25a is a positioning hole used for alignment when forming the lead frame, and the pilot hole 25b is a positioning hole used for alignment when assembling the semiconductor device.

  Next, in the step shown in FIG. 8B, the metal plate 24 is transferred by 1 pitch, and the position to be pressed is determined based on the pilot hole 25a. Then, at the determined position, the stamping dies 22 and 23 are used to press punch the metal original plate 24. A lead part forming hole 27 is formed by the punching die 23, and a pilot hole 25 a, a pilot hole 25 b, and a lead part forming hole 26 are formed by the punching die 22. The position where the punching process is performed by the punching die 23 coincides with the position where the punching process is performed by the punching die 22 in the step shown in FIG.

  8A and 8B, pilot holes 25a, pilot holes 25b, lead portion forming holes 26, and lead portion forming holes 27 are formed as shown in FIG. In the punched region located at the right end of 104, the lead frame 28 used for assembling the semiconductor device is completed. With the above punching process, one cycle of punching is completed.

  In the step shown in FIG. 8D, the metal base plate 24 is moved by one pitch, and the position for fixing the lead frame 28 to the injection mold for forming the envelope is determined based on the pilot hole 25b. . Then, at the determined position, an envelope 29 that surrounds each of the lead portions formed at a plurality of locations is formed. By this process, the lead frame 30 with the envelope for mounting the semiconductor element is completed. Also in this process, punching with the punching dies 22 and 23 is performed simultaneously. Note that the process of assembling the semiconductor device performed after the process shown in FIG. 8D is the same as that in the first embodiment, and thus the description thereof is omitted.

  As described above, according to the present embodiment, as in the first embodiment, it is possible to manufacture a semiconductor device that does not generate resin burrs with high accuracy.

  In the first and second embodiments, it has been described that the steps of forming the lead frame are all performed by punching, but the method of forming the lead frame is not limited to this. For example, after forming the pilot hole and the outer frame portion, the lead frame may be formed using a technique such as etching.

  In the first and second embodiments, the wire bonding method is used and the semiconductor element and the lead portion are electrically connected via the fine metal wire. However, the semiconductor element and the lead portion are electrically connected. Any method can be used as long as it can be connected to the wire, and the method is not limited to the wire bonding method. For example, the semiconductor element and the lead portion may be electrically connected using a wireless bonding method that can be connected without using a thin metal wire. Examples of the wireless bonding method include a face-down bonding method. Further, for example, the semiconductor element and the lead part may be sandwiched using a metal piece, and the semiconductor element and the lead part may be electrically connected.

  INDUSTRIAL APPLICABILITY The present invention is useful as a lead frame manufacturing method capable of suppressing the occurrence of resin burrs with high accuracy and a semiconductor device manufacturing method using the lead frame.

The figure which shows an example of the punching die 1 used for manufacture of the lead frame which concerns on the 1st Embodiment of this invention Sectional drawing in each step in the process of manufacturing the resin-encapsulated semiconductor device according to the first embodiment of the present invention. The figure which shows the lead frame 10 formed through the process shown in FIG. The figure which shows the semiconductor device assembled using the lead frame 10 shown in FIG. The figure which shows the X-X 'cross section of the semiconductor device shown in FIG. Graph showing the number of repairs per month of an injection mold to form an envelope The figure which shows an example of the punching die 21 used for manufacture of the lead frame which concerns on the 2nd Embodiment of this invention. Sectional drawing in each step in the process of manufacturing the resin-sealed semiconductor device which concerns on the 2nd Embodiment of this invention. The figure which shows an example of the punching die 102 used for manufacture of the conventional lead frame Cross-sectional view at each stage in the process of manufacturing a conventional lead frame

Explanation of symbols

4,104 Metal original plate 5, 25, 131, 132 Pilot holes 6, 7, 106, 107 Lead portion forming holes 8, 28 Lead frame 9, 109 Envelope 10 Lead frame 11 with envelope formed External lead 12 Semiconductor element 13 Metal thin wire 14 Envelope filling resin

Claims (3)

A lead frame manufacturing method comprising:
A step of forming at least a part of the lead frame on the metal original plate that is transferred in the same direction at a predetermined pitch together with pilot holes used as positioning holes in the manufacturing process;
Further, using the pilot hole as a positioning hole, completing the lead frame;
Using the pilot hole as a positioning hole, and forming an envelope in a completed lead frame,
A method for manufacturing a lead frame, wherein a pilot hole used in the step of completing the lead frame and a pilot hole used in the step of forming the envelope are the same hole. A method for manufacturing a semiconductor device, comprising:
A step of forming at least a part of the lead frame on the metal original plate that is transferred in the same direction at a predetermined pitch together with pilot holes used as positioning holes in the manufacturing process;
Further, using the pilot hole as a positioning hole, completing the lead frame;
Using the pilot hole as a positioning hole, and forming an envelope in a completed lead frame;
Fixing a semiconductor element to the envelope, and electrically connecting the semiconductor element and a lead formed on the lead frame;
Filling the envelope with resin,
The method of manufacturing a semiconductor device, wherein the pilot hole used in the step of completing the lead frame and the pilot hole used in the step of forming the envelope are the same hole.   The method of manufacturing a semiconductor device according to claim 2, wherein the semiconductor element is a light emitting semiconductor element, and the resin is a transmissive resin.

Images