JPS63140543A - Defect inspection equipment for semiconductor substrate - Google Patents

Abstract

PURPOSE:To obtain inspection accuracy not limited by resolution of an infra-red ray camera, prevent the decrease of detection accuracy of void in the inspection process of void defects of a semiconductor substrate with a large diameter, and make it possible to discover even fine voids, by dividing the image of a semiconductor substrate to be inspected into two or more sections and inputting them. CONSTITUTION:A light radiated from a light source 21 is cut off except infra-red rays by a filter 22, and a semiconductor substrate 24 to be inspected is irradiated by the infra-red rays reflected by a mirror 23. This substrate 24 is a junction type semiconductor substrate wherein two semiconductor wafers are joined. The infra-red rays transmitted through the semiconductor substrate 24 to be inspected are converted into an image signal by an infra-red ray camera 25, which is mounted on an X-Y stage 26 in order to divide the image of the semiconductor substrate 24 to be inspected into, for example, four sections for a signal input. The image converted into the image signal is inspected by an inspection process part 27 for possible voids. A control part 28 controls the X-Y stage 26, and determines whether the semiconductor substrate 24 is acceptable or not, based on the inspection results from the inspection process part 27.

Description

[Detailed Description of the Invention] [Object of the Invention] (Industrial Application Field) The present invention relates to a defect inspection device for semiconductor substrates, and in particular to a bonded semiconductor substrate obtained by bonding two semiconductor wafers. It is used for defect inspection.

(Prior Art) In the above-described direct bonding of semiconductor substrates, internal voids may occur. These voids cannot be detected using visual inspection methods, but they can be discovered through destructive testing, which involves dicing bonded wafers, and non-destructive testing, which uses differences in infrared transmittance. are doing. In the latter type of infrared ray inspection method, the entire image of the semiconductor substrate is generally input into an infrared camera for inspection.

FIG. 3 shows this type of conventional defect inspection apparatus, where J is a light source, 2 is a filter, 3 is a mirror, 4 is a semiconductor substrate to be inspected,
5 is an infrared camera, and 6 is an inspection processing section. FIG. 4 shows the camera input area J1 of the conventional defect inspection apparatus, and it can be seen that the entire image of the substrate 4 is included in the field of view of the camera.

(Problems to be Solved by the Invention) In the conventional method of inputting and inspecting an entire image using a camera, the accuracy of gate detection is determined by the resolution of the camera. First, when inspecting a semiconductor substrate with a larger diameter, the entire image of the semiconductor substrate must be included in the field of view of the camera, so the larger the diameter of the semiconductor substrate, the higher the optical system magnification. As a result, the detection accuracy of Dito inevitably deteriorated.

In addition, minute defects have recently become a problem, and it has been impossible to detect minute defects using conventional equipment, where detection accuracy is determined by the resolution of the camera even on small-diameter wafers.

The present invention has been made in view of the above-mentioned circumstances, and even when void defect inspection is performed on large-diameter semiconductor substrates, the detection accuracy does not deteriorate, and even microscopic defects can be detected on semiconductor substrates. We provide defect inspection equipment.

(Means and effects for solving the problems) The present invention is an apparatus for inspecting defects in a semiconductor substrate to be inspected by irradiating infrared rays onto a semiconductor substrate to be inspected and inputting an image of the transmitted light using an infrared camera. The method further comprises a means for dividing the semiconductor substrate surface to be inspected into at least two parts and inputting an image for each division, and an inspection processing unit for performing defect inspection using the images obtained for each division. Features.

That is, since the image of the semiconductor substrate to be inspected is inputted in at least two sections, it is possible to obtain inspection accuracy that is not limited by the resolution of the infrared camera.

(Example) An example of the present invention will be described below with reference to the drawings. 1st
The figure is a configuration diagram of the same embodiment. In the figure, 21 is a light source.
The light emitted from this light source 21 is filtered by a filter 22 to cut off all but the infrared rays, and the infrared layer is reflected by a mirror 23 and irradiated onto the semiconductor substrate 24 to be inspected. This substrate 24 is a bonded semiconductor substrate made by bonding two semiconductor wafers. The infrared rays transmitted through the semiconductor substrate 24 to be inspected are converted into an image signal by an infrared camera 25.

In this embodiment, as shown in FIG.
In order to input the image into four sections, an infrared camera 25fX is used.
-It is attached to the Y stage 26.

The image converted into an image signal is inspected by the inspection processing section 27 for the presence or absence of gates. The control unit 28 controls the X-Y stage 2
6 and the quality of the semiconductor substrate 24 to be inspected is determined based on the calibration results from the inspection processing section 21.

As an inspection procedure, first of all, the X-Y table 26 is driven and the camera 25 is moved so that the center of the input area 41 of the camera comes to the A1 coordinate in FIG.

Next, camera input and inspection processing are performed. Similarly, A2
, A3, and A4 coordinates, and a final pass/fail judgment is made. In FIG. 2, reference numeral 42 indicates the locus of movement of the center of the camera input area 4.

In the present invention, the infrared camera is movable in the above embodiment, but the semiconductor substrate to be inspected may be movable, or a plurality of cameras may be used to perform classification input at the same time. Furthermore, as long as the number of divisions is two or more, it does not matter, of course.

Furthermore, the present invention can be applied in various ways, such as displaying the image signal from the camera directly on a monitor TV and allowing a person to inspect and judge whether the product is good or bad.

[Effects of the Invention] As described above, according to the present invention, since images of a semiconductor substrate to be inspected are inputted in at least two sections, it is possible to obtain an inspection phase change that is not limited by the resolution of an infrared camera.

Therefore, it is possible to provide a semiconductor substrate defect inspection apparatus that does not reduce detection accuracy even when inspecting large-diameter semiconductor substrates for gate defects, and is capable of detecting even minute gates.

[Brief explanation of the drawing]

FIG. 1 is a configuration diagram of an embodiment of the present invention, FIG. 2 is a diagram showing a camera input area of the same configuration, and FIG. 3 is a configuration diagram of a conventional device.
FIG. 4 is a diagram showing the camera input area of the same configuration. 2... Light source, 22... Filter, 23... Mirror, 24... Semiconductor substrate to be inspected, 25... Infrared camera, 26... X-Y stage, 22... Inspection processing Section, 28...control section. Applicant's representative Patent attorney Takeshi Suzue Critically ill Figure 1 Figure 2

Claims (4)

[Claims] (1) In an apparatus for inspecting the semiconductor substrate to be inspected for defects by irradiating the semiconductor substrate with infrared rays and inputting an image of the transmitted light using an infrared camera, the semiconductor substrate to be inspected is inspected for defects on at least two or more surfaces of the semiconductor substrate to be inspected. 1. A defect inspection apparatus for a semiconductor substrate, comprising means for inputting an image in each division, and an inspection processing section for performing defect inspection using the image obtained in each division. (2) The semiconductor substrate defect inspection apparatus according to claim 1, wherein the semiconductor substrate to be inspected is a bonded semiconductor substrate in which substrates are bonded together. (3) The semiconductor substrate according to claim 1, further comprising means for relatively moving the positions of the infrared camera and the semiconductor substrate to be inspected in order to input the images separately. defect inspection equipment. (4) The semiconductor substrate defect inspection apparatus according to claim 1, wherein a plurality of infrared cameras are used to input the images separately.