JP2810309B2 - Method for producing box-shaped resin molded product for semiconductor device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a box-shaped resin molded product for a semiconductor device.
When the lead frame is inserted into a mold and the box-shaped resin molded body for semiconductor device and the lead frame are integrally molded,
The flash burrs generated on the lead frame, especially at the intersection of the lead frame and the wall surface forming the space of the box-shaped resin molded product for semiconductor devices, can be efficiently removed without causing any damage to the molded product. The present invention relates to a method for producing a high-quality box-shaped resin molded product for a semiconductor device by removing the same.

[0002]

2. Description of the Related Art Semiconductor elements such as ICs and LSIs are affected by changes in ambient temperature and humidity, or by minute dust and dust, and their characteristics are delicately changed. Because it is easily damaged by impact, it is used in a state sealed in a package.

The package system is roughly classified into a hermetic sealing system and a resin sealing system. In the hermetic sealing system, ceramics are generally used, but attempts have been made to use thermosetting resins. When a thermosetting resin is used, a part of the lead frame is formed, and an adhesive is attached to an island portion of the lead frame provided at the center of the resin hollow sealing body (box-shaped resin molded body for a semiconductor device). The semiconductor element fixed by the above is encapsulated in a resin molding for a semiconductor device by insert molding, and a lead frame whose both ends are opened to the inside and outside of the package,
They are connected by bonding wires.

By the way, the integral molding of a lead frame and a box-shaped resin molded body for a semiconductor device is performed by inserting a lead frame into a mold and then injection molding or transfer molding a thermosetting resin in the mold. Made by

However, in this molding method,
The surface of the portion of the lead frame located in the box-shaped resin molded body for semiconductor device, particularly the portion of the lead frame located in the box-shaped resin molded body for semiconductor device is a wall forming a space of the box-shaped resin molded body for semiconductor device. There is a problem that flash burrs of the resin occur at a portion intersecting with the inner surface of the portion, thereby preventing electrical connection between the lead frame and the semiconductor element. Furthermore, even if the flash burrs are small ones that do not hinder the electrical connection, such flash burrs must be completely removed for a semiconductor device that does not want to mix fine dust.

Conventionally, methods for removing such flash burrs include, for example, a blast method using abrasive grains, a method for dissolving and removing flash burrs using chemicals, and a method for removing flash burrs by injecting a high-pressure liquid. Methods are known. However, in the above blast method, since the surface of the resin mold portion is damaged by friction with the abrasive grains, the surface of the resin mold portion must be masked, and there is a problem that the manufacturing process becomes complicated. Also, in the method using chemicals, even though flash burrs can be removed, it is extremely difficult to completely remove them, and furthermore, since ultrasonic cleaning and the like must be performed, the surface of the resin mold portion is damaged, There is a problem that the manufacturing process becomes complicated similarly to the above-mentioned blast method.

In the method of injecting a liquid at a high pressure, the flash burr adhering to the lead frame is removed by removing 100 kg / cm from a portion of the box-shaped resin molded body for a semiconductor device where the flash burr is formed. ^It is necessary to inject ^two or more high-pressure liquids, which causes a problem that cracks are easily generated in the resin mold portion.

The present inventors have been studying the flash burr removing method, and do not come into contact with the exposed portion of the lead frame before insert molding, that is, the box-shaped resin molded product for a semiconductor device. An organic polymer substance having a melting point or softening point equal to or higher than the molding temperature of the sealing body and soluble in a solvent that does not dissolve the sealing body is applied to the portion, and the lead frame is In a state of being set in the mold, the resin is integrally molded by injection or transfer molding, and the obtained resin hollow sealing body is immersed in the solvent to dissolve and remove the organic polymer substance of the lead frame. A method for simultaneously removing flash burrs generated on the upper surface has been previously developed and a patent application has been filed (see Japanese Patent Application Laid-Open No. 2-51260).

In the process of further improving the above invention, the present inventors have continued research on a method of reliably removing only flash burrs by simpler means. For the semiconductor device by roughening at least the surface to be contacted between the lead frame and the internal lead portion (the surface to be contacted with the internal lead portion), of the hollow molding protrusions of the box-shaped resin molded product for the device. The knowledge that irregularities are formed on the flash burr surface of the inner lead part of the box-shaped resin molded body was obtained,
By injecting high-pressure water into these irregularities, we gained new knowledge that flash burrs can be completely removed,
Based on this finding, the present invention has been completed.

[0010]

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a method for manufacturing a box-shaped resin molded product for a semiconductor device which can completely remove flash burrs without damaging a lead frame or a resin molded portion. is there.

[0011]

Means for Solving the Problems The present invention has been proposed to achieve the above object, and is characterized in that a part of a molding die is subjected to a roughening treatment to a specific surface roughness. And That is, according to the present invention, the lead frame to which the semiconductor element is connected is inserted into a mold, and the resin is solidified in the mold, so that the lead frame is integrated and the internal space is formed in the internal space. In a method of manufacturing a box-shaped resin molded product for a semiconductor device in which a semiconductor element is hermetically sealed, a surface roughness of a portion of the mold opposite to the lead frame of a protrusion for forming the space has a surface roughness of 0.5 And a method of manufacturing a box-shaped resin molded product for a semiconductor device, characterized in that the thickness is 20 to 20 μm.

In the conventional method, since the flash burr surface is flat, even if high-pressure water is injected, a sufficient peeling force cannot be applied to the flash burr, and the flash burr is completely removed. However, according to the above-mentioned means, since irregularities are formed on the flash burr surface of the lead frame, when high-pressure water is sprayed on the portions, sufficient high-pressure water is applied to the convex portions of the irregularities, so that sufficient A large amount of peeling force can be applied, and flash burrs can be completely removed from the lead frame.

In the above means, in order to roughen the surface of the molding die, for example, electric discharge machining or shot blasting is used. The surface roughness of the roughened mold surface is preferably 0.5 to 20 μm. When the surface roughness of the metal surface is in this range, the thickness of the flash burr becomes appropriate for peeling, and the flash burr peeling operation becomes easy. The inner leads of the box-shaped resin molded product for semiconductor device obtained by using the mold whose surface is roughened as described above (portions of the lead frame located in the space of the box-shaped resin molded product for semiconductor device). The formed flash burr surface becomes an uneven surface which is roughened similarly to the mold. In the present invention, the value of the surface roughness indicates a value defined in JIS B0601-82, and indicates the maximum height of the uneven surface.

[0014]

DETAILED DESCRIPTION OF THE INVENTION The most important technical feature of the present invention is that the top surface 8a, 8b, 8c of the protrusion 8 of the upper die 7 shown by the imaginary line in FIG. This is because the resin is solidified between the upper die 7 and the lower die 9 to manufacture the box-shaped resin molded product 1 for a semiconductor device. According to this method,
The flash burr formed on the internal lead portion 2b of the lead frame 2 inserted between the upper die 7 and the lower die 9
Since the irregularities corresponding to the irregularities of the tips 8a, 8b, 8c are formed, the flash burrs 3 can be completely removed by applying a sufficiently large peeling force to the convexes.

In FIG. 1, a box-shaped resin molded product for a semiconductor device indicated by reference numeral 1 is formed by injection molding or transfer molding between an upper mold 7 and a lower mold 9 in which the lead frame 2 is inserted. It is formed by solidifying. Thereby, the box-shaped resin molded product 1 for a semiconductor device in which the lead frame 2 is integrated is obtained. As a material constituting the box-shaped resin molded product 1 for a semiconductor device, a thermosetting resin having good adhesion, for example, bisphenol A
Materials such as epoxy resin such as mold, novolak type and glycidylamine type, imide resin such as polyamine bismaleimide and polypyromellitimide, phenol resin and unsaturated polyester resin are used.

The conditions for insert molding vary depending on the resin used, but when epoxy resin is used,
10 to 500 kgf / cm ² , temperature 150 to 2
Molding conditions at 00 ° C. for 1 to 5 minutes are preferred. The lead frame 2 is made of a 42 alloy or a copper alloy. During molding, the surface of the lead frame 2, in particular, the inner surface 10 a of the side wall forming the space 10 of the box-shaped resin molded product 1 for a semiconductor device and the internal lead portion 2 b Flash burrs 3 are generated at a portion 3a where the vertical direction is perpendicular to the portion 3b where the inner surface 10b of the side wall forming the space 10 of the semiconductor device box-shaped resin molded body 1 and the island portion 2c of the lead frame 2 are orthogonal.

The flash burr 3 formed as described above
Since a sufficient peeling force acts on the convex portion of the flash burr 3 by injecting high-pressure water from the injection nozzle at an injection pressure of 100 to 1500 Kgf / cm ² , preferably 20 to 500 Kgf / cm ² , Burrs 3 are easily removed. The flash burrs 3 can be completely removed within at most about 30 seconds of high-pressure water injection, usually within 20 seconds at most. According to this method, compared to the blast method using abrasive grains, the flash burrs 3 are used. Damage can be significantly reduced, and no dust is generated.
It can be understood that the method is suitable as a method for manufacturing a semiconductor device that requires a high degree of cleanliness and precision in that the resin mold is not damaged as compared with the dissolution and peeling method using a chemical.

After the flash burr 3 is removed, the semiconductor device 4 is mounted on the island portion 2c of the lead frame 2 on the box-shaped resin molded product 1 for a semiconductor device as shown in FIG. 4 is a bonding wire 5
Thus, the internal lead portion 2b and the semiconductor element 4 are connected. Next, a semiconductor device in which a lid member 6 such as a transparent or translucent plastic plate, a quartz glass plate, a sapphire plate, an alumina plate or the like is adhered to the opening of the box-shaped resin molded product for semiconductor device 1 and hermetically sealed is provided. It is formed.

[0019]

According to the present invention, flash burrs formed on a lead frame can be easily and reliably removed without damaging a box-shaped resin molded product for a semiconductor device and a lead frame. Thus, a method for manufacturing a high-quality semiconductor device can be provided.

[0020]

The present invention will be described below in detail with reference to examples. As shown in FIG. 1, the lead frame 2 made of 42 alloy in which the inner lead portion 2b and the island portion 2c of the lead frame 2 are plated with gold having a thickness of 1.5 μm is fixed to the upper die 7 and the lower die 9 of a transfer molding machine. Inserted at position. Next, the novolak-type epoxy resin was insert-molded under the conditions of a temperature of 175 ° C., a pressure of 70 kg / cm ² and a time of 2 minutes, and then post-cured at a temperature of 175 ° C. for 4 hours to obtain a semiconductor as shown in FIG. A box-shaped resin molded product 1 for an apparatus was obtained. At this time, the tip surfaces 8a, 8
The surfaces of b and 8c had a roughness of 3 to 15 μm in Rz, and the surface roughness of the flash burr 3 of the obtained molded product was also 3 to 15 μm.

Next, the box-shaped resin molded product 1 for a semiconductor device
Was taken out and washed with water. When water was sprayed from a nozzle having a diameter of 0.5 mm at a pressure of 300 kg / cm ² , the flash burr 3 formed on the lead frame 2 was simply sprayed for 3 seconds. 2, and the lead frame 2 and the resin mold portion were not damaged. After the flash burr 3 thus obtained is removed, the box-shaped resin molded product 1 for a semiconductor device is dried, and then the island portion 2 of the lead frame 2 is dried.
The semiconductor element 4 is die-bonded to c with an epoxy-based silver paste. Next, the internal lead portion 2c and the electrode of the semiconductor element 4 are bonded with the bonding wire 5 (gold wire). However, since the flash burr 3 is completely removed, there is no electrical connection failure in a good state. And the bonding strength also met the standard value.

As described above, in the box-shaped resin molded product obtained by insert-molding the lead frame, the flash burr 3 can be removed in the subsequent cleaning process using high-pressure water even when the injected water pressure is relatively low. Therefore, it is possible to obtain a good box-shaped resin molded product without forming burrs without damaging the lead frame 2 and the resin molded portion.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view showing a hollow sealing body and a lead frame in a state where flash burrs are formed.

FIG. 2 is a cross-sectional view showing the semiconductor device after removing flash burrs.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 Box-shaped resin molded product for semiconductor device 2 Lead frame 4 Semiconductor element 7 Upper die (die) 8 Projection 8a Tip surface (part facing lead frame) 8b Tip surface (part facing lead frame) 8c Tip surface (Part facing the lead frame) 9 Lower die (die) 10 Space

Claims (1)

(57) [Claims] 1. A lead frame to which a semiconductor element is connected is inserted into a mold, and a resin is solidified in the mold, whereby the lead frame is integrated and the semiconductor element is placed in an internal space. In the method for manufacturing a box-shaped resin molded product for a semiconductor device to be hermetically sealed, a surface roughness of a portion of the protruding portion for forming the space in the die opposite to the lead frame has a surface roughness of 0.5 to 2
A method for producing a box-shaped resin molded product for a semiconductor device, characterized in that the thickness is 0 μm.