JPS61108145A - Detecting device for detecting semiconductor pellet - Google Patents

Abstract

PURPOSE:To detect reliably defective semiconductor pellets due to a break and so forth by a detecting device in the simple constitution by a method wherein an He-Ne laser beam is irradiated on the semiconductor pellets through a diaphragm, its reflected light is detected in the light-receiving element, the current value of its output is compared with the current setpoint and whether the pellets are defective or non-defective is decided. CONSTITUTION:A laser beam from an He-Ne laser light source 1 is narrowed by a pinhole plate 4 via a filter 2 and a reflecting mirror 3 and the laser beam is irradiated on the semiconductor pellets of a wafer 5 on an X-Y stage 10. The reflected light is made to incide in a light-receiving element 7. The current value of its output is compared with the prescribed current setpoint in the light-receiving element 7 and when the current value of the output is lower than the setpoint, it is decided that defects such as a break and so forth exist on the pellet. Accordingly, defective pellets due to a break and so forth are detected by the detecting device in the simple constitution with a high reliability.

Description

[Detailed Description of the Invention] [Background of the Invention] Semiconductor integrated circuits (IC, L8, etc.) are manufactured by selectively doping a raw material semiconductor substrate (wafer) with impurities, forming an aluminum layer for electrodes, and forming an insulating layer. A factory that performs so-called wafer etching processes such as attaching an oxide film (
They are shipped in wafer form from the wafer factory (wafer factory), and after arriving at the assembly factory, they are cut into individual pellets through a cutting operation called dicing.

The semiconductor wafer cut into individual pellets retains its shape before dicing, and each semiconductor pellet is successively picked out by a vacuum chuck collet, and placed in the envelope of the semiconductor device. It is attached to the base surface.

By the way, it is possible that such a semiconductor wafer has a semiconductor pellet formed on its periphery as well, and since one side of the semiconductor pellet coincides with the side of the semiconductor wafer, the chipped semiconductor may be Manufactured as pellets.

Semiconductor pellets with such chips formed thereon are not subject to characteristic inspection, so-called glove inspection, but are checked in advance and handled as not subject to any bonding.

Conventionally, semiconductor pellets with chips have been recognized by, for example, an imaging device, and determined to be defective if the chips are more chipped than, for example, the area of a standard mother turn.

However, conventional imaging devices detect chipped semiconductor pellets in proportion to the area of a standard arm turn, resulting in poor reliability and the device itself is expensive.

[Purpose of the invention]

An object of the present invention is to provide a defective semiconductor pellet detection device that can reliably detect defective pellets due to chipping, etc. with a simple configuration. The present invention provides a defective semiconductor pellet detection device for detecting a defective semiconductor pellet located at the periphery of a semiconductor wafer and in which the periphery coincides with one side of the semiconductor pellet. a light-receiving element that allows the reflected light of the light that has passed through the means to be incident on the semiconductor pellet, and an output current of the light-receiving element is compared with a predetermined current value to determine the quality of the semiconductor pellet. and means for making a determination.

[Embodiments of the invention]

FIG. 1 is a block diagram showing an embodiment of a defective semiconductor pellet detection device according to the present invention. In the same figure, helium
There is a neon laser light source 1, and this helium neon laser light source 1 has a beam diameter of about 0.7u and a spread angle of 1.2
11 ra (approximately 1 ra).The laser light from this helium-neon laser light source 1 is made to enter a reflecting mirror 3 via a filter 2.The filter 2 is The light cover can be adjusted according to the type of light receiving element 7, which will be described later.The laser beam from the reflecting mirror 5 passes through the pinhole plate 4 or an appropriate lens, and It is designed to be incident on the - semiconductor pellets in the semiconductor wafer 5 at an incident angle of about ~35@.The angle of the reflecting mirror 5 can be adjusted as necessary.The pinhole plate Reference numeral 4 has a hole with a diameter of about 0.51 mm formed in a plate body, and uses a diffraction phenomenon to change the beam diameter of the laser beam from the helium-neon laser light source 1, for example, into a light [0.25 m
The drawing strength is increased to about as. However, an appropriate lens may be used instead of the pinhole plate.

Figure 2 is a graph showing the experimental results that the pinhole plate 4 can narrow down the °ζ luminous flux, and shows that when the pinhole plate is used, the TEG surface illuminance becomes larger than when there is no pinhole plate. It can be seen that the above-mentioned helium neon A laser light source 1, a filter 2, a reflector 3, and a pinhole plate 4 are each incorporated into the pellet bonding device. It is placed with a space of 50 mx above the semiconductor wafer 5 secured.

The reflected light of the laser light from the semiconductor pellet is made incident on a light receiving element 7 built into the holder 6.

Further, the semiconductor wafer 5 is placed on the upper surface of the X-'l stage 10, and each
By independently moving the direction stage and the Y direction stage, the semiconductor pellet to be picked up within the semiconductor wafer is positioned under the vacuum suction collet 9. The operation of the detection device will be explained below.

When a semiconductor pellet 5, which is a chip to be inspected, is sent directly below the vacuum suction collet 9 of the pick-up arm 8 by the drive of the irradiated with a diameter of
A black ink dot with a diameter of 500 to 600 μm (
If there is a mark), as shown in FIG. 3, the reflection at the mark will be very small.

Here, the ink dot is a defect mark that is marked on the surface of the semiconductor pellet when the characteristics of each semiconductor pellet are inspected before the die bonding process and the semiconductor pellet is determined to be defective. Also, it is said that the reflection at the center is low depending on the 4-turn IC of the semiconductor pellet. However, as shown in Figure 3, which shows the distribution of reflectance along one center line in a single pellet, the image is not optically magnified, and a laser beam with little spread and attenuation is used. , the 8N ratio regarding the brightness and darkness of the IC/f turn and the brightness and darkness depending on the presence or absence of black ink dots is extremely large, so that erroneous determination is unlikely to occur. For this reason, marks can be detected accurately regardless of the IC/f turn. ◇Figure 4 shows the results of scanning a row of pellets at the center of the pellet. In fact, as described above, the determination may be made when the chip comes to rest directly under the collet. When the chip is determined to be good, the bald tsuquag adsorbs the chip into a collet and carries it away to the die bonding position. If it is determined to be defective, it will be left as is. In any case, once the determination is complete, send the next step directly below the collet. In other words, this operation is repeated for each chip. In this figure, the operation of the pickup is omitted, and the pass/fail judgment is performed continuously while linear feeding is continued.

If there is a mark, the output voltage of the light receiving section will drop significantly as shown in the figure, and since the relay will work, the output voltage of the judgment circuit will drop. The low-height muzzle in the figure is caused by the dark part of the IC mark, and the fact that the signal-to-noise ratio is large is also clearly seen in the figure.

In this way, the semiconductor wafer 5 is placed on the vacuum suction collet 9 at the periphery of the semiconductor wafer 5 during the die bonding process, avoiding the semiconductor pellets marked with defective marks among the semiconductor pellets in the semiconductor wafer 5. When the semiconductor pellet is positioned, the action of the present invention starts; that is, the semiconductor wafer 5 usually has chips at its periphery even before dicing;
The semiconductor pellet diced with the peripheral part as one side is defective. Because this defective semiconductor pellet has chips, the laser light incident on the light receiving element 7 is diffusely reflected by the chipped parts. Become some light. Therefore, as shown in FIG. 5, the output signal from the light-receiving element 7 becomes a unique signal that is clearly different from the mark detection signal at first glance, and by recognizing this signal, the presence of a defective semiconductor pellet can be detected. 〇When such a defective semiconductor pellet is recognized, move the Y-direction stage of the X-Y stage 10 one step (semiconductor pellet) in the opposite direction to the Y direction, and then By moving the X-direction stage one step, the next semiconductor pellet is picked up.

The embodiment described above also serves as a device for detecting defects in the characteristics of semiconductor pellets, and is designed to detect defective semiconductor pellets due to chips, etc.; however, the detection of defective semiconductor pellets due to chips, etc. It goes without saying that the detection may be carried out as a separate device from the device for detecting defects in the characteristics of the pellets. According to the defective semiconductor pellet detection device according to the invention, defective pellets due to defects etc. can be detected with high reliability and a simple configuration.

[Brief explanation of the drawing]

Fig. 1 is a configuration diagram showing an embodiment of a defective semiconductor chip detection device according to the present invention, Fig. 2 is an explanatory diagram showing the light condensing effect of a pinhole, and Fig. 3 is the center of a chip without a mark and a chip with a mark. An explanatory diagram showing the distribution of laser beam reflectance along a line, Fig. 4 is an explanatory diagram showing the pass/fail judgment situation when a row of chips is continuously scanned by uniform motion, and Fig. 5 is an explanatory diagram showing the condition of pass/fail judgment when a row of chips is continuously scanned by uniform motion. It is an explanatory view showing an effect. DESCRIPTION OF SYMBOLS 1... Helium neon laser oscillator, 2... Filter, 3... Reflector, 4... Pinhole plate, 5... Semiconductor wafer, 6... Light receiving element holder, 7... Semiconductor photodetector, 8... Pick-up arm of die bonder, 9... Vacuum suction collet, 10... X-Y stage. Agent Tatsuyuki Unuma
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Claims (1)

[Claims] In a defective semiconductor pellet detection device that detects a defective semiconductor pellet that is located at the periphery of a semiconductor wafer and whose periphery coincides with one side of the semiconductor pellet, a helium neon laser light source and the irradiation light flux of this light source are adjusted to an appropriate size. a light-receiving element that allows the reflected light of the light that has passed through the means to be incident on the semiconductor pellet; and a means that compares the output current of the light-receiving element with a predetermined current value to determine the quality of the semiconductor pellet. A defective semiconductor pellet detection device comprising: