JPH04213841A - Resin cutting method and device for resin sealed semiconductor element - Google Patents

Abstract

PURPOSE:To easily remove the burr of molded resin jutting out of the lead peripheral part of a package by non-contact step within a short time assuming the semiconductor element resin-sealed by a molding step as a target element. CONSTITUTION:The title resin cutting device is composed of a laser oscillator 4, a light-guiding channel 5 guiding the laser beams 9 emitted from the laser oscillator 4, a condenser 7 fixed to the end of the light-guiding channel and a field stopping mask interposed in the light-guiding channel on the position in front of the condenser 7. Finally, the burred position of a semiconductor element is irradiated with the laser beams emitted from the laser oscillator 4 so as to remove the burr by the processing mechanisms for the steps such as heating, melting down and separating.

Description

[Detailed description of the invention]

0001

[Industrial Application Field] The present invention relates to a resin cutting method for removing burrs of molded resin protruding from the surrounding area of the leads of a package for a resin-sealed semiconductor element that has been resin-sealed by a molding method. and regarding its equipment.

0002

2. Description of the Related Art In the above-mentioned resin-sealed semiconductor device, when a resin package is molded, the molding material that flows out of the gap in the molding die adheres to the periphery of the leads and forms burrs. Figure 3 shows how this burr occurs.
1 is a lead frame; 2 is a resin package in which a chip (not shown) mounted on the lead frame 1 is sealed;
3 is the burr of the molded resin protruding from the resin package 2 (
The burr 3 is attached to the periphery of the base of the lead drawn out from the resin package 2 (indicated by diagonal lines).

On the other hand, the burrs described above not only impair the appearance of the product, but also become an obstacle when soldering and plating the leads, so burrs are usually removed during the finishing process of the product. Conventional deburring methods in this case include the barrel method, which uses abrasives to remove the burrs;
Alternatively, a resin cutting method such as a high-pressure water blasting method in which burrs are removed by spraying high-pressure water is generally practiced.

0004

[Problems to be Solved by the Invention] Among the conventional resin cutting methods mentioned above, the barrel method uses an abrasive, so the powder of the abrasive may adhere to the product, or the surface of the product may be damaged during polishing. However, the problem is that small scratches occur, and powder adhering to the product requires post-processing to remove burrs and then wash it. In addition, with the high-pressure water blast method,
Before spraying with high-pressure water, it is necessary to pre-treat the burrs using chemicals to float them. As described above, in the conventional resin cutting method, deburring including pre-processing and post-processing requires a lot of effort and time.

The present invention has been made in consideration of the above points, and an object of the present invention is to provide a resin-cutting method and apparatus for a resin-sealed semiconductor element, which makes it possible to easily remove burrs in a short period of time. .

[0006]

[Means for Solving the Problems] In order to solve the above problems, the resin cutting method of the present invention removes burrs by irradiating a laser beam onto a portion where burrs are generated.

[0007] In order to prevent the laser beam from irradiating parts of the product other than the areas where burrs occur, a mask is placed on the optical path of the laser beam to restrict the irradiation range, and the laser beam is transmitted through the mask. It is best to selectively irradiate only certain areas.

Further, the resin cutting apparatus of the present invention for carrying out the above method includes a laser oscillator, a light guide path for guiding the laser beam emitted from the laser oscillator, and a condenser lens attached to the tip of the light guide path. and a field diaphragm mask inserted into the light guide path at a position in front of the condenser lens.

[0009]

[Operation] As described above, by irradiating the portion where burrs occur with a laser beam from the outside, the burrs of the molded resin are removed by the processing mechanism of heating, melting, and evaporation by the laser. Further, the mask serves to restrict the irradiation range of the laser beam to the burr-generating area and prevent the laser beam from irradiating other parts of the product. This makes it possible to remove burrs from the molding resin adhering to the surface of the product in a non-contact manner and in a short time.

0010

DESCRIPTION OF THE PREFERRED EMBODIMENTS Examples of the present invention will be described below with reference to the drawings. Figure 1 shows the configuration of the resin cutting device.
In the figure, 4 is a laser oscillator, 5 is a light guide path for the laser beam extracted from the laser oscillator 4, 6 is a reflection mirror provided at the corner of the light guide path 5, 7 is a condenser lens attached to the tip of the light guide path 5, 8 is a metal mask for a field stop inserted in the middle of the light guide path 5 on the near side of the condensing lens 7. Further, as shown in FIG. 2, the mask 8 has two laser beam transmission holes 8a and 8b, and each transmission hole 8
A and 8b correspond to the base portions of the lead frame 1 pulled out from both sides of the resin package 2, respectively.

Next, the resin cutting operation with the above configuration will be explained. First, the semiconductor element to be resin cut is positioned directly below the condensing lens 7, and when the laser oscillator 4 is excited here, the laser beam 9 emitted from the laser oscillator 4 travels through the light guide path 5 and passes through the mask 8. After passing through the transmission holes 8a and 8b, the light passes through the condenser lens 7 and is irradiated onto the location where the burr 3 is generated as shown in FIG. The burrs 3 of the molded resin irradiated with the laser beam 9 are then heated, melted,
It is evaporated and removed from the lead frame 1. Note that since the laser beam 9 is blocked in areas other than the transmission holes 8a and 8b of the mask 8, the laser beam does not irradiate parts of the product other than the areas where burrs occur, such as the resin package 2, thereby preventing unnecessary scribing. Note that it is also possible to employ an optical fiber as the light guide path 5 of the optical system in the illustrated embodiment.

0012

[Effects of the Invention] As described above, in the resin cutting method and apparatus of the present invention, a laser beam is directed toward the burrs of the molded resin protruding from the resin package of a resin-sealed semiconductor element around the leads. So,
Burrs can be easily removed by non-contact and short-time laser irradiation, reducing the number of finishing steps and significantly improving efficiency compared to conventional methods.

[Brief explanation of the drawing]

FIG. 1 is a configuration diagram of a resin cutting device according to an embodiment of the present invention.

[Figure 2] Plan view of the mask in Figure 1

[Figure 3] Plan view of resin-sealed semiconductor element

[Explanation of symbols]

1 Lead frame 2 Resin package ３　　　Bali 4 Laser oscillator 5 Light guide path 7. Condensing lens 8 Mask 9 Laser beam

Claims (3)

[Claims] [Claim 1] A resin cutting method for removing burrs of the molding resin protruding from the periphery of the leads of a package of a resin-sealed semiconductor element that has been resin-sealed by a molding method. A resin-cutting method for a resin-sealed semiconductor element, the method comprising removing burrs by irradiating a laser beam onto a portion of the resin-sealed semiconductor element. 2. In the resin cutting method according to claim 1, a mask for regulating the irradiation range is placed on the optical path of the laser beam, and the laser beam is transmitted through the mask to selectively irradiate only the burr portion. A resin cutting method for a resin-sealed semiconductor element, characterized by: 3. A laser oscillator, a light guide path for guiding the laser beam emitted from the laser oscillator, a condensing lens attached to the tip of the light guide, and a condensing lens inserted into the light guide at a position in front of the condensing lens. 1. A resin cutting device for resin-sealed semiconductor elements, comprising a field stop mask.