JPH0265220A - Device for recognizing mark of semiconductor substrate - Google Patents

Abstract

PURPOSE:To prevent any reflected ray on an underneath layer around a mark or an element pattern from coming within the range of an identification device thereby enabling the mark to be identified without fail by a method wherein a lighting system to selectively spot-light the mark only is provided. CONSTITUTION:An optical film 3 is used as a lighting device to identify a mark 2 on a semiconductor wafer 1; the end of the optical fiber 3 is closely arranged on the surface of the semiconductor wafer 1; and a focussing lens 4 is arranged on the end to focus the light on the mark 2 to be spot-lighted. Thus, the light emitted from a power supply and passing through the optical fiber 3 is focussed on the mark 2 by the focussing lens 4 to light the mark 2 only. Through these procedures, when the mark 2 is observed by a TV camera or an optical microscope, the mark 2 can be identified without fail not affected by any reflected ray on an underneath layer around the mark 2 or an element pattern not coming within the range of the identification device.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a recognition device for recognizing marks such as characters and symbols made on a semiconductor substrate, and particularly to a device for illuminating the marks.

[Conventional technology]

2. Description of the Related Art Generally, in the manufacturing process of semiconductor devices, marks such as letters and symbols made on a semiconductor substrate are recognized using an optical method in order to confirm the type of the semiconductor substrate before a processing step. Conventionally, this type of recognition device illuminates almost the entire surface of the target semiconductor substrate with an optical lamp, etc.
The mark is read with a TV camera, optical microscope, etc.

[Problem to be solved by the invention]

In the conventional recognition device described above, the device for illuminating the mark illuminates the entire target semiconductor substrate or a relatively wide area including the mark. For this reason, light is reflected by the base layer of the semiconductor substrate around the mark, and an already formed element pattern enters the reading field of view, causing confusion with the mark and making it difficult to recognize the mark. In particular, automatic recognition devices cannot clearly distinguish between mark patterns, element patterns, reflected light, etc., and recognition errors are likely to occur.

An object of the present invention is to provide a mark recognition device for a semiconductor substrate that can perform correct recognition.

[Means to solve the problem]

A mark recognition device for a semiconductor substrate according to the present invention includes an apparatus for recognizing a mark formed on a part of the surface of a semiconductor substrate, and is provided with illumination light for selectively spot illuminating only the mark.

[Effect]

With the above-mentioned configuration, it is possible to prevent reflected light from the underlying layer around the mark and the element pattern from entering the field of view of the recognition device, thereby realizing reliable mark recognition.

〔Example〕

Next, the present invention will be explained with reference to the drawings.

FIG. 1 is a perspective view of a first embodiment of the invention.

In the figure, reference numeral 1 denotes a semiconductor substrate, that is, a semiconductor wafer, and a mark 2 consisting of letters is provided on a part of its surface.

As an illumination device for recognizing the mark 2 on the semiconductor wafer 1, an optical fiber 3 with one end connected to a light source (not shown) is used, and the tip of the optical fiber 3 is brought close to the surface of the semiconductor wafer 1. A converging lens 4 is disposed at the tip of the mark 2 to converge light onto the mark 2 for spot illumination.

Therefore, after the light from the power source passes through the optical fiber 3, it is converged onto the mark 2 by the converging lens 4, and only the mark 2 is illuminated. As a result, when mark 2 is recognized with a TV camera or optical microscope (not shown), reflected light from the underlying layer around mark 2 and the element pattern will not enter the field of view, eliminating these influences and recognizing the mark. It becomes possible to reliably recognize the

FIG. 2 is a front view of a second embodiment of the present invention, where 1 is a semiconductor wafer and 2 is a mark. In addition, 5 is a power source for lighting, 6 is a recognition device such as a TV camera, and 7 is this TV camera 6.
8 is a half mirror placed in front of the mark 2, and 8 is a light shielding plate placed on the mark 2. Here, the light shielding plate 8 has an opening 8a only in a region corresponding to the mark 2.

In this configuration, the light emitted from the light source 5 is reflected by the half mirror 7 and irradiated toward the semiconductor wafer 1. Most of the light is blocked by the light shielding plate 8, but only the area of the mark 2 is irradiated in a spot through the opening 8a. The illuminated mark 2 is then imaged by a TV camera 6, and the mark is recognized.

Therefore, the light from the light source 5 irradiates only the mark 2, making it possible to appropriately recognize the mark without being affected by the reflection from the surrounding underlying layer or the element pattern.

〔Effect of the invention〕

As explained above, since the present invention is provided with an illumination system that selectively illuminates only the mark with a spot, it is possible to prevent reflected light from the underlying layer around the mark and the element pattern from entering the field of view of the recognition device. Reliable mark recognition can be achieved

[Brief explanation of the drawing]

Fig. 1 is a perspective view showing the main parts of the first embodiment of the present invention;
The figure is a front view of a second embodiment of the invention. DESCRIPTION OF SYMBOLS 1... Semiconductor wafer, 2... Mark, 3... Optical fiber, 4... Converging lens, 5... Light source, 6...
TV camera, 7...half mirror-18...shading plate,
8a...Opening.

Claims (1)

[Claims] 1. A mark recognition device for a semiconductor substrate, characterized in that the device recognizes a mark made on a part of the surface of a semiconductor substrate, the device comprising an illumination system that selectively spotlights only the mark.