JPH0330448A - Foreign substance inspecting device - Google Patents

Abstract

PURPOSE:To obtain the title device capable of detecting foreign substances ranging from very fine foreign substances to large foreign substances with high precision without being affected by an interference, which is caused in case light is used, and the reflectivity of the surface of a semiconductor wafer by a method wherein a change of an electrostatic capacity is used for the detection of the foreign substances. CONSTITUTION:In a foreign substance inspecting device for detecting a foreign substance 12 on a semiconductor wafer 3 in a non-destructive manner, a detector 1 for detecting an electrostatic capacity is provided over the wafer 3 which is an object or measurement, the foreign substance on the wafer 3 is detected by a change of the electrostatic capacity between the wafer 3 and the electrostatic capacity detector 1, the above detector 1 is fixed and the upper part of the wafer 3 is scanned by the detector 1 in directions X-Y or spirally by moving the wafer 3 to be measured. Thereby, the foreign substance 12 on the wafer 3 is inspected. For example, a semiconductor wafer 3 is sucked on a conductive supporting stand 4, the stand 4 is moved by an X-axis driving part 6 in a direction X while being made to perform a rotation movement by a step motor 5 and an electrostatic capacity detector 1 scans spirally the wafer 3.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to foreign object inspection for detecting foreign objects on semiconductor wafers.

BACKGROUND OF THE INVENTION In recent years, the patterns of elements formed on semiconductor wafers have become increasingly finer due to higher integration in integrated circuit technology. Therefore, the presence of foreign matter on a semiconductor wafer obstructs the formation of these fine patterns and reduces the yield of integrated circuits.

Therefore, it is necessary to inspect fine foreign particles on semiconductor wafers and to manage the number, size, and distribution of these foreign particles. Conventionally, a so-called laser scattering method has been used to detect foreign matter on a semiconductor wafer, in which a laser light source is incident on the semiconductor wafer, and when a foreign matter is present on the semiconductor wafer, the scattering of the laser light is detected.

There is a region where the ability to solve the problem that the invention is trying to solve is poor, and in the 632.8 nm of the He-No laser, which is most commonly used as a conventional laser light source, the size of foreign particles is extremely It was not possible to detect minute foreign objects with high precision. Furthermore, since light scattering is used, if there are various films on the semiconductor wafer, the scattering state on the surface of the semiconductor wafer differs depending on each film, making accurate measurement impossible.

The present invention detects foreign objects by detecting very small to large foreign objects without being affected by the interference that occurs when using light or by the reflectance of the semiconductor wafer surface by using a static change in volume. This is a foreign object inspection device that detects foreign objects with high precision.

Means for Solving the Problems The present invention has an e-capacitance detector for detecting capacitance on a semiconductor wafer to be measured, and detects a change in static capacitance 1 between the semiconductor wafer and the semiconductor wafer. This method detects foreign objects by moving the semiconductor wafer or moving the semiconductor wafer and a capacitance detector to inspect foreign objects on the wafer.

Function: According to the foreign matter inspection device of the present invention, the capacitance 1 can be measured at a high I.
n''!- is easy to obtain and the change in capacitance is linear, so very minute foreign matter can be detected, and the size of the foreign matter can be detected with good linearity.

Furthermore, it becomes possible to inspect foreign matter when various films are present on a semiconductor wafer, which has been difficult with conventional optical methods, and it is possible to realize a highly sensitive and highly accurate foreign matter inspection device.

EXAMPLE Hereinafter, an example in which a capacitance detector is fixed and a semiconductor wafer is moved to scan the wafer will be described based on the apparatus configuration diagram shown in FIG.

In FIG. 1, a capacitance detector 1 is installed at the tip of a support arm 2 and fixed at a distance of 100 to 200 μm above a semiconductor wafer 3. On the other hand, the semiconductor wafer 3 is vacuum-adsorbed onto a conductive support base 4, and this support base 4 is rotated by a step motor 5 and moved in the x direction by a drive unit θ. This causes the capacitance detector to scan the wafer in a spiral manner. If a foreign object exists between the capacitance detector and the semiconductor wafer, the capacitance between the capacitance detector and the wafer changes compared to when there is no foreign object, and this change causes the foreign object to be detected. The rotation speed of the wafer is faster near the inner periphery than near the outer periphery in order to maintain a constant linear velocity between the capacitance detector and the tool. On the other hand, in the X direction, the wafer moves in steps of approximately 20 μm each time it rotates. In this way, the semiconductor wafer is scanned. On the other hand, the capacitance change obtained by the capacitance detector passes through the capacitance calculator 7 and the particle size converter 8 and becomes information on the size of the foreign object. At the same time, information on the scanning position is transmitted from the step motor and the X-axis drive unit to the position calculator 9, and information on the position and size of the foreign object is collectively displayed on the display unit 1o, and a map of the foreign object on the wafer and A particle size histogram of foreign particles is displayed.

Effects of the Invention As described above, according to the foreign matter inspection apparatus of the present invention, foreign matter on a semiconductor wafer can be inspected with high sensitivity and precision.

[Brief explanation of drawings]

FIG. 1 shows a groove diagram of a foreign matter inspection device according to the present invention. 1...Capacitance detector, 2...Capacitance detector support arm, 3...Semiconductor wafer,
4...Support stand, 5...Step motor, θ...X-axis drive unit, 7...Capacitance calculation unit, 8... ...Particle size calculation section, 9...
Position calculation section, 1o...Display section, 11...
・Shaft, 12...Foreign object.

Claims (2)

[Claims] (1) A foreign object inspection device that non-destructively detects foreign objects on a semiconductor wafer, which has a detector that detects capacitance on the semiconductor wafer to be measured, and has a sensor that detects capacitance between the semiconductor wafer and the capacitance detector. A foreign substance on the semiconductor wafer is detected by the change in the capacitance of the capacitance, and the wafer shape is
A foreign matter inspection device that inspects foreign matter in the shape of a semiconductor wafer by scanning in a direction or in a spiral pattern. (2) The foreign matter inspection device according to claim 1, characterized in that the capacitance detector is scanned in one direction in the above-mentioned scanning direction, and the semiconductor wafer is rotated to scan the wafer shape in a spiral manner. .