JP2001358254A - Semiconductor device and manufacturing method therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a semiconductor device having high reliability by preventing flanking and fallout of a metal film covering the outside surfaces of resin bumps. SOLUTION: A depression 14 is formed near a portion to be mounted with a device on one surface of a metal base material 10 in such a way as to align in plane arrangement with an external connection terminal 26 electrically connected to a semiconductor device 20 to be mounted on the portion to be mounted with the device. The inside of the depression 14 is covered with a metal film 16 that is not dissolved by an etching liquid dissolving the metal base material 11. The edge of the opening of the depression 14 is swaged to make the peripheral portion of the metal film 16 form a retaining portion 16a projecting to the inside of the depression 14. The semiconductor device 20 is mounted on the portion to be mounted with a device on the one surface of the metal base material 10 where the retaining portion 16a is formed. The electrode terminal of the semiconductor device 20 is bonded to the inside of the metal film 16 with a bonding wire 22. The semiconductor device 20, the bonding wire 22 and the one surface of the metal base material 10 including the depression 14 are sealed with resin. Then the metal base material 10 is melted and removed to expose the metal film 16.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method in which a resin bump portion is formed integrally with a resin sealing portion for sealing a semiconductor element, and a conductor film is applied to an outer surface of the resin bump portion to form an external connection terminal. The present invention relates to a semiconductor device and a method for manufacturing the same.

[0002]

2. Description of the Related Art FIG. 7 shows a structure in which a resin bump portion is formed integrally with a resin sealing portion for sealing a semiconductor element, and a metal film is applied to an outer surface of the resin bump portion to form a bump-shaped external connection terminal. 1 shows a method for manufacturing a semiconductor device. FIG. 7A shows a resist pattern in which both surfaces of a metal base material 10 such as a copper foil are coated with a resist, and exposed and developed to expose a portion of one surface of the metal base material 10 where external connection terminals are to be formed. 12 is formed, and the metal substrate 10 is formed using the resist pattern 12 as a mask.
Is etched to form a concave portion 14 on one surface of the metal substrate 10. The concave portion 14 is for forming a bump serving as an external connection terminal.

FIG. 7 (b) shows that the inner surface of the recess 14 formed in the metal substrate 10 is plated, and the inner surface of the recess 14 is coated with the metal film 1.
6 shows a state covered with the coating. The metal film 16 serves as a portion that covers the outer surface of the bump of the external connection terminal, and is formed of a metal that is not dissolved by an etchant used when dissolving and removing the metal base material 10. FIG. 7C shows a state in which the resist on both sides of the metal base 10 has been removed, and a concave portion 14 having an inner surface covered with a metal film 16 is formed on one side of the metal base 10.

FIGS. 7 (d) to 7 (g) show a process of mounting a semiconductor element 20 on a metal substrate 10 to form a semiconductor device. FIG. 7D shows a state in which the semiconductor element 20 is mounted on the element mounting portion on one surface of the metal base 10 using the conductive paste 18. FIG. 7E shows a state in which the semiconductor element 20 and the metal film 16 are electrically connected by wire bonding. At the time of wire bonding, the electrode terminals of the semiconductor element 20 and the inner surface of the metal film 16 at the bottom of the recess 14 are connected by bonding wires 22. FIG. 7F shows a semiconductor device 20 and a bonding wire 22 using a resin sealing device.
And a region including the concave portion 14 is sealed with a resin. 2
Reference numeral 4 denotes a resin sealing portion. FIG. 7G shows a state in which the metal substrate 10 is dissolved and removed, and the metal film 16 is exposed to the outside to obtain a semiconductor device. The metal film 16 is formed by covering the outer surface of the resin bump portion 24 a projecting in a bump shape from the lower surface of the resin sealing portion 24, and the bump-shaped external connection terminal 26 is formed by the resin bump portion 24 a and the metal film 16. The formed semiconductor device is obtained.

[0005]

In the semiconductor device shown in FIG. 7 (g), since the semiconductor element 20 and the metal film 16 are directly connected by the bonding wires 22, there is no need to form a wiring pattern for wiring. In addition to this, there is an advantage that the semiconductor device can be easily manufactured, the size of the semiconductor device can be reduced, and mass production can be easily performed using a conventional manufacturing apparatus. However, in the above semiconductor device, only the metal film 16 is adhered and held on the outer surface of the resin bump portion 24a, and if the adhesion between the resin and the metal film 16 is insufficient, the resin bump portion 24a will There is a problem that the metal film 16 peels off from the outer surface. For this reason, studies have been made to solve the problem that the metal film 16 is peeled off by chemically roughening the surface of the metal film 16 that contacts the resin and selecting a resin material having good adhesion to the metal film 16. I have.

The present invention has been made to solve these problems, and an object of the present invention is to form a resin bump portion integrally with a resin sealing portion for sealing a semiconductor element. A semiconductor device in which a metal film is adhered to an outer surface of an external connection terminal to form an external connection terminal, in which the metal film of the external connection terminal is prevented from peeling and falling off, and can be provided as a highly reliable product; and It is an object of the present invention to provide a preferable method for manufacturing the semiconductor device.

[0007]

To achieve the above object, the present invention has the following arrangement. That is, a plurality of resin bumps are formed integrally with the resin sealing portion on the mounting surface side of the resin sealing portion for resin sealing the semiconductor element, and the outer surface of the resin bump portion is covered with a metal film, In a semiconductor device in which an inner surface of the metal film and an electrode terminal of a semiconductor element are wire-bonded, a peripheral portion of the metal film covering a base of the resin bump portion extends into a resin forming the resin bump portion. It is characterized in that it is formed in a locking portion that performs. In addition, the fact that the locking portion is formed on the entire periphery of the peripheral portion of the metal film strengthens the bonding between the resin bump portion and the metal film, and prevents peeling and falling off of the metal film. It is valid.

Further, in the method of manufacturing a semiconductor device, the external connection terminals electrically connected to the semiconductor element mounted on the element mounting portion are arranged on one side of the metal base near the element mounting portion. A concave portion is formed together, and an inner surface of the concave portion is covered with a metal film made of a metal that is not dissolved by an etching solution that dissolves the metal base material. Then, an opening edge of the concave portion is crushed to form a peripheral portion of the metal film. Forming a locking portion protruding inside the concave portion, mounting the semiconductor element on the element mounting portion on one surface of the metal base on which the locking portion is formed, and connecting the electrode terminal of the semiconductor element and the metal film. After wire bonding with the inner surface of the, the semiconductor element, after bonding one side of the metal substrate including the bonding wire and the concave portion with resin,
The method is characterized in that the metal substrate is dissolved and removed to expose the metal film. Further, by plating the inner surface of the concave portion with gold plating, palladium plating, nickel plating, and palladium plating in this order to form a metal film, a metal film having good wire bonding properties can be formed, and soldering can be performed. It is possible to manufacture a semiconductor device that can be reliably mounted by using the method described above.

[0009]

Preferred embodiments of the present invention will be described below in detail with reference to the accompanying drawings. The method for manufacturing a semiconductor device according to the present invention is similar to the above-described conventional method for manufacturing a semiconductor device in that a semiconductor device is manufactured using a metal base material. That is, a concave portion is formed on one surface of a metal substrate, the inner surface of the concave portion is covered with a metal film, a semiconductor element is mounted on an element mounting portion on one surface of the metal substrate, and the semiconductor element and the metal film are separated. It is electrically connected by wire bonding, and after sealing the surface of the metal base on which the semiconductor element is mounted with resin, the metal base is dissolved and removed, thereby projecting in a bump shape on the outer surface of the resin sealing portion. The semiconductor device is obtained by forming the external connection terminals.

A feature of the method of manufacturing a semiconductor device according to the present invention lies in a method of processing a metal film for forming an external connection terminal formed on a metal substrate. Hereinafter, first, a processing method until a metal base is processed to form a metal frame on which a semiconductor element is mounted will be described. FIG.
Shows a processing step from forming the concave portion 14 in the metal base material 10 to covering the inner surface of the concave portion 14 with the metal film 16. FIG. 1A shows a state in which a metal substrate 10 such as a copper foil is coated on both sides with a resist 11. Since the metal base 10 is dissolved and removed using an etching solution in a later step, it is preferable to select a material that can be easily dissolved and removed by etching for the metal base 10. In the present embodiment, a copper material having a thickness of 0.15 mm is used as the metal substrate 10.

FIG. 1B shows a state in which the resist 11 is exposed and developed to form a resist pattern 12 exposing a portion of the metal substrate 10 where the concave portion 14 is to be formed. The recess 14 is provided only on one surface of the metal base 10. Therefore, the resist 11 on one surface of the metal base 10 is exposed and developed to form a resist pattern 12. FIG. 1C shows a state in which the metal base 10 is etched using the resist pattern 12 as a mask to form a concave portion 14 in the metal base 10. In this embodiment, the recess 14 has a plane dimension of 0.6 m.
m and a depth of about 0.1 mm.

FIG. 1D shows a state in which the inner surface of the concave portion 14 formed by etching the metal substrate 10 is plated, and the inner surface of the concave portion 14 is covered with the metal film 16. Reference numeral 13 denotes a plating resist that covers the surface of the metal base 10 after dissolving and removing the resist pattern 12 used for etching the metal base 10. Resist for plating 1
3 is etched to expose the concave portion 13 of the metal base material 10 and to perform plating. Although the plating for forming the metal film 16 can be appropriately selected, in the present embodiment, from the side exposed on the outer surface of the external connection terminal, gold plating-palladium plating-nickel plating-palladium plating is applied to form a four-layer structure. Has formed. With such a plating configuration, the wire bonding property of the metal film 16 can be improved, and the soldering property at the time of mounting can be improved. The total thickness of the metal film 16 is 5 to 10 μm. FIG. 1 (e) shows a state where the plating resist 13 is dissolved and removed after plating. A concave portion 14 is formed on one surface of the metal base 10, and the inner surface of the concave portion 14 is covered with a metal film 16.

FIG. 2 shows a processing step characteristic of the present invention.
A processing step of crushing an opening edge of the concave portion 14 and forming a locking portion 16a on a peripheral portion of the metal film 16 covering the inner surface of the concave portion 14 is shown. FIG. 2A shows that the inner surface is a metal film 16.
The metal substrate 10 has a concave portion 14 covered by the metal substrate 10. FIG. 2B shows a state in which the metal base 10 is crushed. The punch 30 has an end surface that contacts the metal substrate 10 formed as a substantially flat surface, and a plane dimension of the end surface of the punch 30 is formed slightly larger than the opening size of the concave portion 14. By horizontally protruding, the opening edge of the concave portion 14 is slightly crushed, and the metal film 16 adhered to the inner surface of the concave portion 14 by the crushing process.
Is projected to the inside of the concave portion 14 to form the locking portion 16a. Reference numeral 32 denotes a step formed on the opening edge of the recess 14 by crushing.

As shown in FIG. 2B, the crushing process performed on the concave portion 14 of the metal base 10 is performed by cutting the edge of the metal film 16 into the concave portion 1.
4 is intended to protrude inside the metal film 16. By projecting the peripheral edge of the metal film 16 inside the recess 14, the metal film 16 is formed on the resin when the semiconductor element is sealed with resin. This prevents the metal film 16 from sticking or peeling off from the resin. The example shown in FIG. 2B is an example in which the locking portion 16a is processed so as to project substantially parallel to the plane of the metal base material 10.
The metal film 16 can be prevented from peeling off by processing so as to slightly protrude inward of the metal film 4. Punch 3
When the metal substrate 10 is pierced by the punch 30 and the metal substrate 1
6 may easily be protruded into the recess 14.

The locking portion 16 a may be formed in a ring shape over the entire periphery of the metal film 16, or a part of the periphery of the metal film 16 may be crushed to form the periphery of the metal film 16. The portion may be partially formed to protrude inside the concave portion 14 to form the locking portion 16a. FIG. 3 shows a metal in which a concave portion 14 is formed in a metal base 10, an inner surface of the concave portion 14 is covered with a metal film 16, and the concave portion 14 is crushed to form a locking portion 16 a on a peripheral portion of the metal film 16. FIG. 3 shows a plan view of the frame 40. Reference numeral 17 denotes an element mounting portion for mounting a semiconductor element. A recess 14 having an inner surface covered with a metal film 16 is formed around the element mounting portion 17. FIG. 4 is an enlarged plan view showing the metal frame, and shows that a locking portion 16 a is formed on the peripheral edge of the metal film 16. Metal substrate 10
In the case where the recesses 14 and the like are processed as described above, a strip-shaped or large-sized metal substrate 10 is actually used as a workpiece, and the metal substrate 10 is subjected to required processing to form the metal frame 40. I do.

FIG. 5 shows a process of mounting the semiconductor element 20 on the metal frame formed as described above and sealing it with a resin to manufacture a semiconductor device. FIG. 5A shows a state where the semiconductor element 20 is mounted on the element mounting portion 17 of the metal frame 40 using the conductive paste 18. FIG. 5B shows a state in which the semiconductor element 20 and the metal film 16 are electrically connected by wire bonding. At the time of wire bonding, the electrode terminals of the semiconductor element 20 are bonded to the inner surface of the metal film 16 at the bottom of the recess 14. 22 is a bonding wire. As another method of connecting the semiconductor element 20 and the metal film 16 by wire bonding, a gold bump is previously formed on the inner surface of the metal film 16 at the bottom of the concave portion 14, and the gold wire is placed on the gold bump. A bonding method is also possible.

FIG. 5C shows the semiconductor element 2 on the metal base 10.
0 shows a state in which the surface on which No. 0 is mounted is sealed with resin. At the time of this resin sealing, the semiconductor element 20, the bonding wire 22
Then, resin molding is performed so as to seal the metal film 16 (the concave portion 14). The resin is filled in the concave portion 14 by resin sealing using a resin sealing mold, and the resin sealing portion 24 is integrally molded with the resin. FIG. 5 (d) shows that the metal base 1
0 is dissolved and removed with an etching solution containing ferric chloride as a main component to obtain a semiconductor device. Metal substrate 1
By dissolving and removing 0, the semiconductor element 20 and the bonding wires 22 are sealed in the resin sealing portion 24, and the external connection terminals 26 are formed in a bump shape on the outer surface on the mounting surface side of the resin sealing portion 24. A protruding semiconductor device is obtained.

The external connection terminals 26 are formed by covering the outer surface of a resin bump portion 24a which is formed into a bump shape by filling the concave portion 14 with a resin when the resin is sealed. I have. FIG. 2 shows the peripheral portion of the metal film 16.
Since the locking portion 16a is formed as shown in (b),
At the time of resin sealing, the locking portion 16a is molded into the resin by getting into the resin, thereby preventing the metal film 16 from peeling off or falling off from the resin bump portion 24a. At the base of the resin bump portion 24a, a protrusion 24b is formed by a step 32 formed on the surface of the metal base material 10 when the metal film 16 is crushed.

According to the semiconductor device of the present embodiment, the locking portion 16a is provided at the peripheral portion of the metal film 16 to prevent the metal film 16 from peeling off or falling off, so that the inner surface of the metal film 16 is roughened. This eliminates the need to improve the adhesion between the metal film 16 and the resin, and allows the metal film 16 to be configured with an emphasis on wire bonding properties, so that the semiconductor element 20 and the external connection terminals 16 can be reliably connected. It becomes possible to connect electrically. In addition, as a resin material used for resin sealing of the semiconductor element 20, it is possible to select a material in which heat dissipation is more important than adhesion to the metal film 16, thereby improving the reliability of the semiconductor device. It becomes possible.

Incidentally, the metal frame on which the semiconductor element is mounted can be formed in various shapes, whereby the semiconductor device can also be formed in any shape. The method for manufacturing a semiconductor device shown in FIG. 6 is characterized in that the semiconductor device is manufactured using a metal frame in which a recessed element mounting portion is formed. FIG. 6A shows that a resist pattern 12 for etching is formed on the surface of the metal substrate 10, and a concave portion 14 for forming an external connection terminal by half-etching and a device mounting concave portion 50 for mounting the semiconductor device 20. It is in a formed state. FIG. 6B shows a state in which the surface of the metal base material 10 is covered with a plating resist 13, and the inner surface of the concave portion 14 and the inner surface of the element mounting concave portion 50 are plated with a metal film 16.
52. The metal films 16 and 52 can be formed into a plurality of layers by sequentially performing appropriate plating.

FIG. 6C shows a characteristic step in the method of manufacturing a semiconductor device according to the present invention, in which the opening edges of the concave portion 14 and the element mounting concave portion 50 are crushed to form the concave portion 14 and the element mounting concave portion 50. The locking portions 16a and 52a are formed on the peripheral edges of the metal films 16 and 52 covering the inner surfaces. The semiconductor element 20 is mounted on the metal frame 40 thus formed.
Is mounted via an adhesive layer, the surface of the metal frame 40 on which the semiconductor element 20 is mounted is resin-sealed (FIG. 6D), and after the resin sealing, the metal frame 40 is dissolved and removed. Thus, a semiconductor device in which the external connection terminals 26 protrude from the outer surface of the resin sealing portion 24 in a bump shape can be obtained.

The semiconductor device according to the present embodiment has an element mounting recess 5.
By mounting the semiconductor element 20 at 0 and lowering the mounting position of the semiconductor element 20, the thickness of the semiconductor device can be reduced. Further, the device mounting recess 50 is connected to the semiconductor device 2.
The center part where 0 is mounted is formed in a shape that is one step lower,
Since the semiconductor element 20 can be wire-bonded to a stepped portion of the metal film 52 covering the inner surface of the element mounting recess 50, the semiconductor element 20 and the ground potential can easily be electrically connected with the metal film 52 as a ground potential or a power supply potential. It is possible to make a connection.

In the case of the semiconductor device of this embodiment, similarly to the above-described embodiment, the peeling or falling off of the metal film 16 covering the outer surface of the resin bump portion 24a can be effectively prevented. Also, the metal film 52 on which the semiconductor element 20 is mounted can be prevented from peeling from the resin sealing portion 24 by forming the locking portion 52a, thereby improving the reliability of the semiconductor device. Can be done.

[0024]

According to the semiconductor device of the present invention, as described above, the metal film forming the external connection terminal can be effectively prevented from peeling or falling off, and is provided as a highly reliable semiconductor device. can do. Further, according to the method for manufacturing a semiconductor device according to the present invention, a locking portion can be easily formed on a metal film, and a highly reliable semiconductor device in which peeling or falling off of a metal film is prevented can be manufactured. Will be possible.
This also ensures wire bonding,
It is possible to provide a semiconductor device having excellent heat dissipation.

[Brief description of the drawings]

FIG. 1 is an explanatory view showing a step of manufacturing a metal frame used for manufacturing a semiconductor device.

FIG. 2 is an explanatory view showing a process of forming a locking portion on a peripheral portion of a metal film.

FIG. 3 is a plan view showing an example of a metal frame used for manufacturing a semiconductor device.

FIG. 4 is an explanatory view showing a metal frame in an enlarged manner.

FIG. 5 is an explanatory diagram showing an embodiment in which a semiconductor device is manufactured using a metal frame.

FIG. 6 is an explanatory view showing another embodiment of manufacturing a semiconductor device using a metal frame.

FIG. 7 is an explanatory view showing a conventional method for manufacturing a semiconductor device.

[Explanation of symbols]

 REFERENCE SIGNS LIST 10 metal base material 11 resist 12 resist pattern 13 resist 14 concave portion 16 metal film 16 a locking portion 17 element mounting portion 18 conductive paste 20 semiconductor element 22 bonding wire 24 resin sealing portion 24 a resin bump portion 24 b protrusion 26 external connection terminal 30 punch 40 metal frame

Claims (4)

[Claims] A plurality of resin bumps are formed integrally with a resin sealing portion on a mounting surface side of a resin sealing portion for resin sealing a semiconductor element, and an outer surface of the resin bump portion is covered with a metal film. In addition, in a semiconductor device in which an inner surface of the metal film and an electrode terminal of a semiconductor element are wire-bonded, a peripheral portion of the metal film covering a base of the resin bump portion is
A semiconductor device characterized by being formed in a locking portion extending in a resin forming the resin bump portion. 2. The semiconductor device according to claim 1, wherein said locking portion is formed around the entire periphery of said metal film. 3. A concave portion is formed on one surface of the metal substrate in the vicinity of the element mounting portion in accordance with a planar arrangement of an external connection terminal electrically connected to a semiconductor element mounted on the element mounting portion, After covering the inner surface of the concave portion with a metal film made of a metal that is not dissolved by an etching solution that dissolves the metal base material, the opening edge of the concave portion is subjected to crushing processing so that the peripheral portion of the metal film projects inside the concave portion. A locking portion is formed, a semiconductor element is mounted on an element mounting portion on one surface of the metal base on which the locking portion is formed, and an electrode terminal of the semiconductor element and an inner surface of the metal film are wire-bonded. A semiconductor characterized in that after one surface side of the metal base including the semiconductor element, the bonding wire and the concave portion is resin-sealed, the metal base is dissolved and removed to expose the metal film. Device manufacturing method. 4. The method for manufacturing a semiconductor device according to claim 3, wherein a metal film is formed by plating the inner surface of the concave portion in the order of gold plating, palladium plating, nickel plating and palladium plating.