JPH03256340A - Sensitivity inspection wafer for foreign matter inspection device and its manufacturing method - Google Patents

Abstract

PURPOSE:To improve the sensitivity inspection accuracy of various kinds of foreign matter inspection devices and enhance workability by forming a dummy foreign matter based on an ion CVD processing method in an attempt to form said dummy foreign matter equal to or larger than submicron and over large- sized on the surface of a wafer used as a means to inspect the sensitivity of the foreign matter inspection devices. CONSTITUTION:A sensitivity inspection wafer 1 is provided with projected dummy foreign matters 2, 3, 4, and 5 formed of the surface of a wafer substrate 6, such as silicon. The dummy foreign matters 2, 3, 4, and 5 are formed based on an ion beam CVD process stated below. More specifically, the wafer substrate 6, such as silicon is placed at a specified spot in a reaction chamber at first where reaction gas, say, tungsten carbide gas is ejected from a gas nozzle. After the gas ejection is over, ion beam 8 is irradiated in a region where the dummy foreign matters are to be formed. Then, the ion beam 8-irradiated region is heated on the wafer substrate 6 and the tungsten carbide is pyrolytically decomposed. The tungsten is then deposited on the irradiation region. For example, one dummy foreign matter 2 is formed thereon.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to foreign matter inspection technology, and is particularly effective when applied to wafer technology used to check the detection sensitivity of a foreign matter inspection device that performs an appearance inspection on the surface of a semiconductor wafer. related to technology.

[Prior Art] This type of foreign matter inspection technology includes, for example, a light emitting unit that irradiates inspection light onto the surface of a semiconductor wafer to be inspected, and a mechanism that detects light scattered on the semiconductor wafer surface via a polarizing plate. Foreign body inspection technology using foreign body inspection equipment equipped with
For example, it is described in Japanese Patent Application Laid-Open No. 54-101390.

[Problem W1 to be Solved by the Invention] By the way, when using the foreign object inspection device as described above, the detection sensitivity must be checked and calibrated in order to always maintain the detection sensitivity appropriately. In this case, for example, standard particles, which are spheres of a predetermined size, are coated on the wafer, and the foreign object inspection is performed using these particles as pseudo foreign objects to check the detection sensitivity.

However, with such technology, it is difficult to apply a predetermined number of standard particles to a wafer, so it is difficult to determine what proportion of the number of foreign particles detected as foreign substances is to the total number of standard particles applied. , it is not possible to properly evaluate the detection probability.

In addition, since it is not possible to attach standard particles to a specific position, it is possible to check whether a pseudo foreign object exists at a location where it has been detected as a foreign object (noise may be determined as a detection signal for a pseudo foreign object). Confirmation work is required, and the work efficiency of sensitivity check is inferior.

On the other hand, wafers for detection probability of foreign object inspection devices are also known.

In this wafer, a recess is formed using a lithography technique and the recess is regarded as a pseudo foreign object, so that it is possible to form a pseudo foreign object, that is, a recess at a specific position.

However, since the inner peripheral surface and bottom surface of the recess are smooth, when the recess is irradiated with inspection light such as a laser beam, the inspection light tends to be scattered only at the sharp edges of the recess. be. For this reason, when the inspection light irradiated onto the wafer surface is scattered by a pseudo foreign object, it is difficult to generate scattered light of appropriate intensity. This tendency is noticeable in foreign matter inspection equipment (which irradiates inspection light to the outside of the body).

Furthermore, since the shape of an actual foreign object is usually convex and has a height and width equal to or smaller than the width, the concave shape of the pseudo foreign object is significantly different from the shape of the actual foreign object. Furthermore, in the case of a plurality of pseudo foreign objects of different sizes, since the depth of the recess remains constant and only the diameter is changed, scattered light with an intensity corresponding to the size of the pseudo foreign objects is less likely to occur. For this reason, it is unsuitable as a pseudo foreign object, and the sensitivity check accuracy is poor.

SUMMARY OF THE INVENTION An object of the present invention is to provide a wafer for checking the sensitivity of a foreign object inspection apparatus and a method for manufacturing the same, which makes it possible to improve the accuracy and workability of sensitivity checks for various foreign object inspection apparatuses.

The above and other objects and novel features of the present invention will become apparent from the description of this specification and the accompanying drawings.

[Means for Solving the Problems] Representative inventions disclosed in this application will be summarized as follows.

In the invention as claimed in claim 1, when forming a pseudo-foreign object with a size of submicron or larger on the surface of a wafer used for checking the sensitivity of a foreign object inspection device, the pseudo-foreign object is formed using an ion beam C.
It is formed by a VD processing method.

According to a second aspect of the invention, a plurality of convex pseudo foreign objects having different sizes are formed on the surface of a sensitivity check wafer by the manufacturing method according to the first aspect.

According to a third aspect of the invention, the pseudo foreign objects of the sensitivity check wafer of the foreign object inspection apparatus according to the second aspect are shaped substantially similar to each other.

[Function] According to the invention described in claims 1 to 3, when manufacturing the sensitivity check wafer, by using the ion beam CVD processing method, the surface of the sensitivity check wafer is
It is possible to form a plurality of pseudo foreign objects whose shape is similar to the shape of the actual foreign object, and by controlling the ion beam irradiation time etc., it is possible to form pseudo foreign objects of different sizes into mutually similar shapes. By narrowing down the ion beam diameter, it is also possible to form pseudo foreign objects of submicron size.

For this reason, when the inspection light irradiated onto the surface of the sensitivity check wafer is scattered by the pseudo foreign matter, the appropriate intensity and
In other words, scattered light with an intensity corresponding to the size of the pseudo foreign object is likely to occur,
In particular, scattered light of appropriate intensity is likely to be generated even in a foreign matter inspection apparatus in which the angle of irradiation of the inspection light onto the wafer is small.

Therefore, it is possible to improve the accuracy and workability of the sensitivity check. Furthermore, it is possible to calibrate detection sensitivities between foreign object inspection apparatuses with different detection methods with high accuracy.

[Example] An embodiment of the present invention will be described based on the drawings.

As shown in FIGS. 1(a) to (d), the sensitivity check wafer 1 (see FIG. 2) has convex pseudo foreign objects 2, 3, 4, 5 on the surface of a wafer substrate 6 made of silicon or the like. formed and composed.

Here, each pseudo foreign material 2, 3, 4.5 is formed to increase in size in this order. In addition, each pseudo foreign object 2, 3, 4
．． 5 has a curved mountain shape extending from the base to the tip, and has similar shapes.

Although not particularly limited, in this example, nine pseudo-foreign objects of the same size form one set, and four sets of different sizes are placed on the surface of the sensitivity check wafer l, as shown in FIG. They are arranged regularly in rows and two columns. Also,
In each set, nine pseudo foreign objects are regularly arranged in three rows and three columns.

Next, a method for manufacturing such a sensitivity check wafer 1 will be explained based on FIG. 3.

The pseudo foreign objects 2, 3, and 4.5 are formed, for example, by the following ion beam CVD processing method.

That is, as shown in FIG. 3, first, a wafer substrate 6 made of silicon or the like is placed at a predetermined location in a reaction chamber (not shown), and a reaction gas such as tungsten carbide (W (Co), ) gas is ejected to create a tungsten carbide (W (Co), ) gas atmosphere in the reaction chamber. Thereafter, the ion beam 8 is irradiated onto the region where the pseudo foreign matter is to be formed. Here, a liquid metal such as gallium is used for the ion source.

The area of the wafer substrate 6 that is irradiated with the ion beam 8 is heated, and tungsten carbide (W (Co),
) is thermally decomposed, and as a result, tungsten is deposited in the irradiated area, forming, for example, one pseudo foreign material 2.

Although the pseudo foreign objects 3 and 4.5 are formed in the same manner as the pseudo foreign object 2, they can be formed in successively larger sizes by sequentially increasing the ion beam irradiation time.

In this example, nine pseudo foreign objects of the same size are arranged in 3 rows and 3 columns to form one set, and 4 sets of different sizes of pseudo foreign objects are arranged in 2 rows and 2 columns. The number of foreign objects or the types of different sizes may be any number, and the arrangement thereof may be arbitrary.

According to this embodiment, the following effects can be obtained.

That is, in manufacturing the sensitivity check wafer, by using the ion beam CVD processing method, a foreign material having a similar shape to the surface of the sensitivity check wafer 1 but different in size, and whose shape is similar to the shape of the actual foreign object. It is possible to form a plurality of pseudo foreign objects 2, 3, and 4.5, and by narrowing down the beam diameter of the ion beam 8, it is also possible to form submicron-sized pseudo foreign objects, which improves the accuracy of sensitivity checks. It is possible to improve the

Furthermore, when the inspection light irradiated onto the surface of the sensitivity check wafer 1 is scattered by the pseudo foreign objects 2, 3, 4.5,
Scattered light with an appropriate intensity, that is, an intensity corresponding to the size of the pseudo foreign object, is likely to be generated, and in particular, even in a foreign object inspection apparatus where the irradiation angle of the inspection light on the wafer is small, scattered light with an appropriate intensity is likely to be generated.

Therefore, it is possible to calibrate the detection sensitivity between foreign object inspection apparatuses with different detection methods with high precision.

Furthermore, since a plurality of pseudo foreign objects 2, 3, 4.5 can be formed at specific positions on the surface of the sensitivity check wafer l, a plurality of pseudo foreign objects 2, 3, 4.5 can be formed as in this embodiment. They can be arranged regularly or in a certain pattern. As a result, when determining whether the sensitivity of the foreign object inspection device is appropriate, it is necessary to use the foreign object map obtained by checking the sensitivity of the foreign object inspection device, that is, pseudo foreign object 2,
In the display results showing the distribution of 3°4.5, it is possible to visually judge whether or not a similar regular arrangement or pattern is displayed, that is, by just looking at it, which improves the workability of sensitivity checks. be able to.

Although the invention made by the present inventor has been specifically explained above based on Examples, it goes without saying that the present invention is not limited to the above Examples and can be modified in various ways without departing from the gist thereof. Nor.

For example, the pseudo foreign substances 2, 3, and 4.5 are made of tungsten, but they may also be made of a predetermined material used in a semiconductor process, such as polysilicon, silicon oxide, aluminum, or molybdenum.

In this case, a reactive gas that deposits a predetermined material may be used.

Also, if the ion source of the ion beam 8 is a liquid metal,
It may be silicon, boron, or arsenic.

Furthermore, pseudo foreign particles 2, 3, and 4.5 of different sizes are formed by changing the irradiation time of the ion beam 8, but processing conditions such as the concentration of the reactant gas or the beam diameter or beam current of the ion beam 8 can be changed. It may be formed by changing.

Furthermore, in the above embodiment, tungsten or the like is deposited on the surface of the wafer substrate 6 to form the pseudo foreign matter 2°3.4.5, but as shown in FIGS. 4(a) to (C), ,
The pseudo foreign matter 12 may be formed by first etching the wafer substrate 6 by ion beam irradiation with the ion beam 8 and then depositing tungsten or the like. This is because at the beginning of ion beam CVD processing, ion beam etching is performed without supplying a reactive gas, and then the reactive gas is supplied under appropriate conditions, that is, conditions where the deposition rate is higher than the etching rate. By doing so, deposition of tungsten and the like begins, and finally a convex pseudo foreign material 12 can be formed. In this case, the adhesion between the pseudo foreign matter 12 and the wafer substrate 6 is significantly improved, and as a result, the pseudo foreign matter 12 can be prevented from falling off from the sensitivity check wafer, and the durability is excellent. The effect is weighted.

In addition, in the above explanation, the invention made by the present inventor was mainly applied to the field of application, which is a wafer technology for checking the sensitivity of a foreign matter inspection device that inspects foreign matter on the surface of a semiconductor wafer. The invention is not limited to this, but can be widely applied to wafer technology for checking the sensitivity of other foreign particle inspection devices.

[Effects of the Invention] The effects obtained by typical inventions disclosed in this application are briefly explained below.

According to the invention described in claims 1 to 3, when manufacturing the sensitivity check wafer, by using an ion beam CVD processing method, the sensitivity check wafer surface is coated with:
It is possible to form a plurality of pseudo foreign objects whose shape is similar to the shape of the actual foreign object, but with different sizes and approximately similar shapes, and submicron-sized pseudo foreign objects can also be formed. It is possible to improve the accuracy and workability of the sensitivity check. Furthermore, it is possible to calibrate detection sensitivities between foreign object inspection apparatuses with different detection methods with high accuracy.

[Brief explanation of drawings]

FIGS. 1(a), (b), (c), and (d) are enlarged cross-sectional views showing pseudo foreign objects on a sensitivity check wafer, which is an embodiment of the present invention. FIG. A plan view, FIG. 3 is an explanatory diagram showing a manufacturing apparatus for a sensitivity check wafer, and FIGS. 4(a), (b), and (c) are pseudo foreign objects of a sensitivity check wafer according to another embodiment of the present invention. It is an explanatory view showing a formation process of. 1... Wafer for sensitivity check, 2-5, 12...
...Pseudo foreign matter, 8...Ion beam. Figure 1 Figure 227- Figure (b) (C)

Claims (1)

[Scope of Claims] 1. In forming pseudo foreign matter of submicron size or larger on the surface of a wafer used for sensitivity check of a foreign matter inspection device, it is characterized in that it is formed by an ion beam CVD processing method. A method for manufacturing a wafer for sensitivity checking. 2. A wafer for sensitivity check of a foreign matter inspection apparatus, characterized in that a plurality of convex pseudo foreign objects of different sizes are formed on the surface of the wafer for sensitivity check by the manufacturing method according to claim 1. 3. The wafer for sensitivity check of a foreign matter inspection apparatus according to claim 2, wherein the pseudo foreign matter is formed in substantially similar shapes to each other.