JPS63172432A - Method of deburring resin molded product - Google Patents

Abstract

PURPOSE:To make it possible to remove thin burr in the same bath without giving damage to a resin part, by immersing a resin molded product in aqueous solution, and alternately repeating the step for performing electrolysis of the aqueous solution with the metal part of the resin molded product as one electrode and the step for performing ultrasonic wave washing of the metal part in the aqueous solution. CONSTITUTION:A semiconductor device after resin sealing is immersed in NaOH solution 6 for a specified time period. With an outer lead 2 of the semiconductor device as, e.g., a cathode, at first, a DC voltage is applied. H2 gas 5 is yielded between the outer lead 2 of the semiconductor device and thin burr 4 by the electrolysis of the NaOH solution 6. Thus the thin burr 4 is removed. Then a high frequency signal is imparted to an ultrasonic wave vibrator 12 from an ultrasonic wave source 11 for a specified period, and ultrasonic wave washing is performed. Thus the electrolytic deburring and the ultrasonic wave washing are alternately repeated in a short period. Therefore a problem of obstruction to the yield of H2 gas bubbles, which are to be formed in the electrolysis, can be solved. The two steps can be performed in the same bath approximately at the same time.

Description

[Detailed Description of the Invention] [Industrial Application] This invention is a method for removing burrs from resin molded products, which removes thin resin burrs that flow out and adhere to metal parts other than the sealed part during m* sealing. It is about the method.

[Conventional technology]

Conventionally, the assembly process of a resin-sealed semiconductor device as a resin-molded product includes a process of punching out dam burrs and a process of removing thin burrs (hereinafter referred to as a deburring process) that occur after resin encapsulation.

FIG. 3 is a diagram showing the state of the semiconductor device after the dam burr punching process. In this diagram, 1 is a package resin part, 2 is an external lead, 3 is a tie bar, and 4 is a thin strip.

Generally, the deburring process includes ultrasonic cleaning to mechanically remove thin burrs 4 or cleaning with high-pressure water jets, and pretreatment with N.
It consists of a step of peeling off the thin burrs 4 from the frame base material using electrolysis of an aOH solution.

Next, the principle of the deburring process will be explained with reference to FIG.

In this figure, the same symbols as in FIG. 3 indicate the same parts,
5 is U, gas, 6 is NaOH solution, 7 is an anode, 8 is a DC power supply, 9 is 0. Gas, 10 is a solution tank.

To remove the thin burrs, first, the semiconductor device sealed with a-liquid is immersed in a NaOH solution 6, and a DC voltage is applied using the external lead 2 as a cathode. Then, by electrolysis of this NaOH solution 6, H2 gas 5 is generated on the external lead 2 of the semiconductor device, that is, on the cathode side. The generation of this H gas 5 is
NaOH dissolution wR dissolution R6 which has entered between the external lead 2 of the semiconductor device and the thin burr 4 attached on the external lead 2 is also performed, so that the thin burr 4 is removed from the outer lead 2 under the thin burr 4.
Summer (2 gases 5 floats up).

This process is called electrolysis.

Next, remove the thin burr 4 that has risen above the external lead 2 using NaO
Ultrasonic cleaning is performed in H solution 6 and mechanically removed by ultrasonic vibration. This method is called ultrasonic scraping.

Additionally, a mechanical removal method using a stream of high-pressure water is also commonly used instead of this ultrasonic cleaning.

This method is called hydraulic stripping.

[Problem that the invention seeks to solve]

In the conventional deburring method for semiconductor devices as described above, water pressure deburring is the most convenient method for mechanically removing thin burrs 4 after electrolytic deburring. If it is directly injected, it will damage the resin part, so IfI! A jig is required to shield the fat part from high-pressure water flow, and the jig must be replaced when processing products with different resin external shapes, making it difficult to implement when processing a large number of products in small quantities. There was a point.

In addition, although the removal method using ultrasonic deburring is versatile for a wide variety of products, compared to the removal method using high-pressure water, it is less
If the external force applied to is small and a large amount of thin burrs 4 is generated, the thin burrs 4 will be removed in areas where the NaOH solution 6 could not penetrate between the thin burrs 4 and the external lead 2 during electrolytic deburring.
There was a problem in that it became difficult to remove.

It was also considered that ultrasonic cleaning could be performed during electrolysis to increase the effect, but this resulted in the problem that the bubbles of H3 gas 5 that were supposed to be generated by electrolysis were not generated. .

This invention was made to solve these problems, and it is a resin molded product that is versatile for a wide variety of products and can reliably remove thinning burrs without damaging the 1ItI1 part. The purpose is to obtain a deburring method.

[Means for solving problems]

The method for deburring resin molded products according to the present invention includes the steps of immersing the resin molded product in an aqueous solution, and then electrolyzing the aqueous solution using the metal part of the V1g resin molded product as one electrode; The process of performing ultrasonic cleaning is repeated alternately.

[Effect]

In this invention, peeling of thin burrs attached to the metal part by gas generated from the metal part serving as an electrode during electrolysis and ultrasonic cleaning for removing the peeled thin burrs are alternately and repeatedly performed.

〔Example〕

FIG. 1 is a diagram for explaining an embodiment of the method for removing burrs from a resin molded product according to the present invention.

In this figure, the same symbols as in FIG. 4 indicate the same parts,
11 is an ultrasonic oscillation power supply, 12 is an ultrasonic transducer, and 13 is a control circuit.

Next, a method for removing burrs from a resin molded product according to the present invention will be explained.

The present invention is characterized in that the effect of deburring is increased by repeating electrolytic deburring and ultrasonic deburring in a short cycle alternately.

That is, under the control of control circuit #13, NaO is first heated for a certain period of time as shown in the timing chart of FIG.
The external leads 2 of the semiconductor device immersed in the H solution 6 and sealed with a resin are used as cathodes, for example, by applying a DC voltage to the N a
11□ gas 5 is generated between the external lead 2 of the semiconductor device and the thin burr 4 by electrolysis of the solution 6, and the thin burr 4 is peeled off. Ultrasonic cleaning is performed by applying a high frequency signal from the ultrasonic oscillation power source 11 to the ultrasonic vibrator 12 for a certain period of time.

In this way, by repeating electrolytic sludge collection and ultrasonic cleaning alternately in short cycles, the H that would be generated by electrolysis due to ultrasonic vibration during electrolytic sludge removal is removed.
The problem of inhibiting the generation of bubbles of 8 gases can be solved, and the two steps can be carried out almost simultaneously in the same tank. Therefore, the synergistic effect of these can be used to achieve a perfect fit without impairing versatility.

Incidentally, in the above embodiment, description has been made regarding the removal of burrs from semiconductor devices, but the present invention is not limited to only semiconductor devices, but can also be applied to the removal of thin burrs attached to metal parts of other vI4I4 type products.

〔Effect of the invention〕

As explained above, this invention includes a step of immersing a resin molded product in an aqueous solution, then electrolyzing the aqueous solution using the metal part of the resin molded product as one electrode, and a process of ultrasonically cleaning the metal part in the aqueous solution. Since it is repeated alternately, 4Itws
This has the effect that thinning burrs can be reliably removed in the same tank without damaging the parts.

[Brief explanation of the drawing]

FIG. 1 is a diagram for explaining an embodiment of the method for removing burrs from resin molded products of the present invention, FIG. 12 is a timing chart for explaining switching of the fH source, and FIG. Diagram 4 showing an example of thin burrs occurring after sealing.
The figure is a diagram for explaining a conventional deburring method. In the figure, 1 is the package resin part, 2 is the external lead,
3 is tie bar, 4 is thin beam, 5 is H2 gas, 6 is NaO
H solution, 7 is an anode, 8 is a DC power supply, 9 is 0. gas, 10
11 is an ultrasonic oscillation power supply, 12 is an ultrasonic transducer, and 13 is a control circuit. Note that the same reference numerals in each figure indicate the same or corresponding parts. Agent Masuo Oiwa (2 others) Figure 1 Figure 2 Figure 3 Figure 4

Claims (1)

[Claims] In a method for removing burrs from a resin molded product that flows out and adheres to a metal part other than the sealed part during resin sealing, the resin molded product is immersed in an aqueous solution, and then the resin molded product is immersed in an aqueous solution. A method for deburring a resin molded product, comprising alternately repeating a step of electrolyzing the aqueous solution using the metal part as one electrode and a step of ultrasonically cleaning the metal part in the aqueous solution.