JPH0320648A - Foreign matter inspecting apparatus - Google Patents

Abstract

PURPOSE:To detect foreign matter on a surface with high sensitivity by simultaneously irradiating one point on the surface of a semiconductor substrate with laser beams having a wavelength of 500 - 700nm forming an angle of 30 deg. or less with respect to said surface in two or more directions. CONSTITUTION:A wafer chuck 6 is positioned on a stage part 7 consisting of Y-, X- and Q-stages to suck a wafer. Next, the laser beam 1b having a wavelength of 500 - 700nm emitted from an He-Ne laser tube 1a is equally divided into laser beams 1c, 1d in X- and Y-directions through a beam splitter 2 and these laser beams are simultaneously focused to one point 4 on the wafer through mirrors 3a, 3b. The scattering beam at the point 4 is detected by a detection system 5. As mentioned above, by simultaneously irradiating the wafer with laser beams in two directions, the foreign matter on the surface of the wafer can be detected with high sensitivity.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to an apparatus for inspecting foreign matter on a patterned semiconductor substrate.

Conventional technology As semiconductor integrated circuits become more highly integrated, elements become smaller and chips become larger. As the number of man-hours increases as the performance of semiconductor players increases, it is necessary to eliminate the presence of foreign substances that can cause fatal damage to circuit pattern formation in the semiconductor manufacturing process. In particular, if the pattern is based on a submicron minimum dimension of 1 μm or less, a single submicron foreign particle will cause the chip to be rejected. Therefore, to ensure high yield,
An ultra-clean environment is required. Typical monitoring methods for maintaining this clean environment include counting the number of particles in the air using a particle counter, and counting the number of particles on a wafer without a pattern using scattering of laser light. It's a method.

Problems to be Solved by the Invention This monitoring method cannot monitor problems specific to patterned wafers during the semiconductor manufacturing process, and is not a sufficient process monitor. The present invention solves the above problems and provides an apparatus that directly counts and manages particles on a patterned wafer during the manufacturing process.

Means for Solving the Problems The present invention irradiates a patterned wafer during the manufacturing process with laser light from two directions, eliminates the influence of pattern edges, and detects foreign substances on the patterned wafer with high sensitivity. It is an inspection device.

Function: By using this inspection device, it is possible to directly control particles during the manufacturing process on patterned wafers without using a special monitor wafer, and it is also possible to monitor problems specific to patterned wafers. Become. This makes it possible to realize a production line with a high yield.

Embodiment The foreign matter inspection apparatus of the present invention will be explained with reference to an embodiment. 1st
The figure shows the configuration of the main parts of the foreign matter inspection device of the present invention.

The wafer chuck 6 is located above a certain station part 7 from the Y stage, the X stage, and the Q stage, and vacuum-chucks the wafer. 6 3 from He-No laser tube 1
The 3 nm laser beam 1b passes through the beam splitter 2
The laser beams are equally divided into an x-direction laser beam 1c and a Y-direction laser beam 1d, and their angles are changed by mirrors 3a and sb so that they are simultaneously focused at one point 4 on the wafer. A detection system 5 for detecting scattered laser light is provided directly above a point 4 where laser light from two directions is simultaneously focused.

A wafer to be inspected 1o with an oxide film etching pattern is inspected using the foreign matter inspection apparatus of the present invention, and FIG. The diagram is shown in Figure 3a.

By setting the irradiation angle of the laser beam at about 2 to 3 degrees from the wafer to be inspected to avoid scattering from the pattern edges,
Only the foreign object part will scatter the laser light. However, when the laser beam 1C is emitted from one direction, minute foreign matter 11 is hidden behind the pattern edge, as shown in FIG. 3b.
cormorant. Therefore, by irradiating the laser beams 1c and 1d from the X-Y directions according to the present invention, the minute foreign matter 11 is captured in the irradiation range of the other laser beam 1d and becomes detectable, as shown in FIG. 3C. .

In the above embodiment, 833 nm He--Ne laser light was used, but this may be any wavelength from 600 nm to 100 nm. Although the laser light from one light source was divided into equal parts using a beam splitter, it is also possible to use separate light sources in the X and Y directions.

1 and the number of directions may be 2 or more.

Effects of the Invention By using the apparatus of the present invention, it is possible to control particles during the manufacturing process without creating a special monitor wafer, and it is also possible to monitor problems peculiar to wafers with scratches and patterns. This makes it possible to find problems early, realize a high-yield production line, and greatly reduce costs.

[Brief explanation of the drawing]

Figure 1 is a structural diagram of the main parts of the foreign matter inspection apparatus according to the present invention, Figure 2 is a schematic diagram of the foreign matter inspection apparatus according to the present invention when performing an inspection, and Figure 3a is a diagram showing the part of the foreign matter on a wafer. The enlarged view, FIG. 3b, is a cross-sectional view of the foreign object portion shown in FIG. 3a in the X direction, and FIG. 3C is a cross-sectional view of the foreign object portion shown in FIG. 3a, in the Y direction. 1a...He-Ne laser tube, 1
b...Laser light (633nm), 1C...
...X direction laser light (833 nm), 1d---
--Y direction laser light (633 nm), 2...
Beam splitter, 3a...Mirror 3b...
・・・Mirror, 4...Point where laser beams from two directions are brought into focus at the same time, 6...Scattered light detection system for laser beam, 6...Wafer chasok, completed. ...
... Stage part, 8... Briar alignment part, 9... Cassette loader part, 1o...
...Wafer to be inspected, 11...Minute foreign matter, 12a
...X direction stage scan range, 12b...
...Y direction stage scan range, 13...
・P-type silicon substrate, 14... Oxide film, 15.
...Scattered light due to minute foreign matter.

Claims (2)

[Claims] (1) One point on the surface of a semiconductor substrate is irradiated with laser light of 500 nm to 700 nm from two or more directions at an angle of 30 degrees or less with the semiconductor substrate surface, and the sum of the scattered intensities of this laser light is used to measure the surface area. A foreign object inspection device characterized by detecting foreign objects. (2) The foreign matter inspection device according to claim 1, wherein the angle between the laser beams is 90°±5°.