JPH0658885A - Method and apparatus for inspecting foreign matter - Google Patents

Abstract

PURPOSE:To obtain a method and an apparatus for detecting a foreign matter buried in an object to be inspected, especially a foreign matter buried in a film formed in the object to be inspected, by the use of light transmitted through the object. CONSTITUTION:The foreign matter inspecting apparatus being employed during photoresist process in the fabrication of semiconductor integrated circuit comprises an object 11 subjected to inspection of foreign matter, an optical system 12 for irradiating the object 11 with light 17 from a light source 18, and a section 13 for detecting light transmitted through the object 11 through an optical sensor 19. The optical system 12 irradiates the object 11 with light 17 from the main surface side thereof and the light 17 transmitted through the object 11 is detected through the detecting section 13 thus detecting a foreign matter 16 buried in a resist film 15 formed on a transparent wafer 14 for the object 11.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to foreign matter inspection technology,
Particularly in the detection of foreign matter buried inside the inspection object, a technique effective when applied to the foreign matter inspection device and the foreign matter detection method using the same which can detect the foreign matter by the transmitted light passing through the inspection object. Regarding

[0002]

2. Description of the Related Art For example, in the manufacture of a semiconductor integrated circuit device, since the photoresist process is a process of forming a pattern which serves as a mask in forming a semiconductor integrated circuit, it is important to reduce foreign matters generated in the photoresist process. It is a key point. In this photoresist process, the occurrence of resist foreign matter is high, and its detection capability is required.

Therefore, conventionally, for example, as shown in FIG. 4, a resist film 2 or the like formed on a wafer 1 is irradiated with light 4 from a light source 3 and reflected by a foreign substance 5 on the resist film 2. 4 is detected by the light receiver 6 and the presence or absence of the foreign matter 5 is determined.

As a technique similar to this, for example, there is a resist processing technique described in "LSI Handbook" P423 to P424, published by the Institute of Electronics and Communication Engineers, November 30, 1984, etc.

[0005]

However, in the prior art as described above, although it is possible to detect the foreign matter adhering to the surface of the resist film, it is buried in the resist film such as foreign matter in the resist liquid and the It is difficult to detect foreign objects that do not appear on the face.

Therefore, it is not possible to prevent such a pattern short circuit due to foreign matter in the film. Particularly, as the degree of integration of semiconductor integrated circuits increases, as the patterns for forming semiconductor elements become finer, these It is desired to improve the film quality of resist films and insulating films.

Therefore, an object of the present invention is to utilize the transmitted light of an object to be inspected to remove foreign matter which is buried in the surface of the object to be inspected, particularly foreign matter in a film formed on the object to be inspected. It is an object of the present invention to provide a foreign matter inspection device capable of detecting and a foreign matter detection method using the same.

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

[0009]

Among the inventions disclosed in the present application, a brief description will be given to the outline of typical ones.
It is as follows.

That is, the foreign matter inspection apparatus of the present invention is a foreign matter inspection apparatus for detecting foreign matter in a face plate-like object to be inspected, and an optical system for irradiating the object to be inspected with light and an object to be inspected. And a detector for detecting the transmitted light.

Further, the detection section is arranged on the main surface side and the back surface side so as to sandwich the inspection object with respect to the light of the optical system.

In this case, the object to be inspected is a film to be inspected formed on a face plate-like object which easily transmits light.

Further, the foreign matter detecting method using the foreign matter inspecting apparatus of the present invention detects a foreign matter by transmitting light having a wavelength longer than that of the optical system to the object to be inspected.

Further, another foreign matter detection method using the foreign matter inspection apparatus of the present invention is to detect a foreign matter by controlling the detection sensitivity of a detection section installed on the back side of the object to be inspected.

[0015]

According to the foreign matter inspection apparatus and the foreign matter detection method using the same described above, the optical system and the detection unit are provided, so that when the foreign matter of the inspected object is detected, the main surface side of the inspected object is detected by the optical system. It is possible to transmit light from the sensor and to detect the transmitted light by the detection unit installed on the back side of the inspection object.

Further, since the detection unit is installed on the main surface side and the back surface side of the object to be inspected, the intensity of transmitted light by the detection unit installed on the main surface side and the intensity of transmitted light by the detection unit installed on the back surface side. Can be sensed.

This makes it possible to detect the presence / absence of foreign matter in the object to be inspected, particularly foreign matter buried in the film to be inspected formed on the face plate of the object to be inspected.

In particular, when the detection probability of a foreign substance is improved by using long-wavelength light in the optical system and the detection sensitivity of the detection unit is controlled, the type and transmittance of the object to be inspected or the film to be inspected, The detection sensitivity can be changed according to the size and shape of the foreign matter, and detection can be performed with optimum detection accuracy.

[0019]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a schematic configuration diagram showing a foreign matter detection unit of a foreign matter inspection apparatus according to an embodiment of the present invention, FIG. 2 is an internal configuration diagram showing the foreign matter inspection apparatus of this embodiment, and FIG. 3 is a foreign matter inspection apparatus. FIG.

First, the structure of the foreign matter detecting portion of the foreign matter inspecting apparatus of this embodiment will be described with reference to FIG.

The foreign matter detecting section of this embodiment is used, for example, in a foreign matter inspecting apparatus in a photoresist process in the manufacture of a semiconductor integrated circuit device. It is composed of an optical system 12 for irradiating and a detection unit 13 for detecting the light transmitted through the inspection object 11. The optical system 12 transmits the light from the main surface side of the inspection object 11, and the transmitted light is the detection unit. A foreign substance in the object 11 to be inspected is detected by the sensor 13.

The object 11 to be inspected has a resist film (film to be inspected) 15 formed on a transparent wafer (face plate-like object) 14 such as quartz which easily transmits light, and a foreign substance 16 buried in the resist film 15. Is detected.

The optical system 12 is installed above the main surface side of the object 11 to be inspected, and for example, a light 17 having a long wavelength is used to improve the detection probability. This light 17 is emitted from the light source 18 to the object 11 to be inspected. Is being irradiated.

The detection unit 13 is installed on the back side of the inspection object 11 and is composed of, for example, an optical sensor 19 whose detection sensitivity can be controlled. The detection unit 13 can be selected according to the type of the inspection object 11 and the size of the foreign matter 16. The detection sensitivity is adjusted.

The foreign matter detecting section constructed in this way is shown in FIG.
A transfer arm 20 for transferring the inspection object 11 as shown in FIG.
A loader section 21 in which the inspected object 11 before the inspection is stored and an unloader section 22 in which the inspected object 11 after the inspection is stored
It is housed inside a foreign matter inspection device equipped with.

Then, the objects to be inspected 11 stacked on the loader section 21 are conveyed one by one directly below the optical system 12 by the conveying arm 20, and the foreign matter 16 is inspected at this detection position, and then the conveying arm. The inspected object 11 is housed in the unloader unit 22 by returning 20 to the original state.

Further, the operation instruction of the foreign substance inspection device, the foreign substance inspection result, etc. are displayed on the display 23 shown in FIG. 3, and the whole device is controlled by inputting each instruction through the keyboard 24.

Next, with respect to the operation of this embodiment, a procedure for detecting foreign matter will be described.

First, one inspection object 11 stacked on the loader section 21 is conveyed by the conveying arm 20 to a detection position immediately below the optical system 12. Then, the light source 1 of the optical system 12
The object 17 to be inspected is irradiated with the light 17 from 8 and the detection of the foreign matter 16 buried in the resist film 15 is started.

Further, the light 17 emitted from the light source 18
To the resist film 15 formed on the transparent wafer 14 which is easily transmitted. In this case, the light 17 is either reflected or transmitted depending on the presence or absence of the foreign matter 16 in the resist film 15, and the transmitted light 17 is detected by the optical sensor 19 of the detection unit 13 installed on the back side of the inspection object 11.

As a result, when the foreign matter 16 is present, the light 1
7 is reflected, it is known that the foreign matter 16 exists in the resist film 15 when the transmitted light 17 sensed by the optical sensor 19 is less than the light 17 emitted from the light source 18, and the transmitted light 17 The amount of the foreign matter 16 can be recognized according to the ratio of 17.

Subsequently, after the inspection of the foreign matter 16 is completed, the transport arm 20 is returned to the original state, and the inspected object 11 is stored in the unloader section 22 and similarly stacked on the loader section 21. All the inspection objects 11 are inspected.

Therefore, according to the foreign matter inspection apparatus of the present embodiment, the optical system 12 for irradiating the inspected object 11 with the light 17 is provided.
And a detection unit 1 for detecting the light 17 transmitted through the inspection object 11.
3 is provided, when the inspection object 11 is inspected, the light 17 is transmitted from the main surface side of the inspection object 11 from the light source 18 of the optical system 12, and the transmitted light 17 of the detection unit 13 is transmitted. The foreign substance 1 buried in the resist film 15 formed on the transparent wafer 14 as detected by the optical sensor 19
6 can be detected.

Further, by using the light 17 having a long wavelength as the light source 18, it becomes possible to detect a small foreign matter 16, thereby improving the detection probability of the foreign matter 16 and changing the detection sensitivity of the optical sensor 19. If
Optimal detection accuracy can be obtained according to the size and shape of the foreign matter 16.

Although the invention made by the present inventor has been specifically described based on the embodiments, the present invention is not limited to the embodiments and various modifications can be made without departing from the scope of the invention. Needless to say.

For example, the foreign matter inspecting apparatus of the present embodiment has been described for the case of inspecting the foreign matter 16 in the resist film 15, but the present invention is not limited to the above-mentioned embodiments, and an oxide film, It is also widely applicable to the inspection of nitride films and the like.

It is also possible to provide a detection unit on the main surface side and the back surface side of the object to be inspected and inspect the foreign matter by detecting the intensity of transmitted light by both detection units.

In the above description, the case where the invention made by the present inventor is mainly applied to the foreign matter inspection device in the photoresist process in the manufacture of semiconductor integrated circuit devices, which is the field of use thereof, has been described, but the invention is not limited to this. Instead, the present invention can be widely applied to other manufacturing processes of semiconductor integrated circuit devices such as formation of an interlayer insulating film and an insulating protective film, and further inspection of foreign substances such as an inspected object through which light is transmitted.

[0039]

The effects obtained by the typical ones of the inventions disclosed in the present application will be briefly described as follows.
It is as follows.

(1) By providing an optical system for irradiating the object to be inspected with light and a detector for detecting the light transmitted through the object to be inspected, the optical system can be used when detecting foreign matter in the object to be inspected. With this, light can be transmitted from the main surface side of the inspection object, and the transmitted light can be sensed by the detection unit installed on the back surface side of the inspection object. It becomes possible to detect a foreign substance buried in the film to be inspected formed on the face plate of the inspected object.

(2). By installing the detection unit on the main surface side and the back surface side so as to sandwich the inspection object with respect to the light of the optical system, the detection unit installed on the main surface side and the back surface side Since the intensity of the transmitted light can be sensed by the detection unit installed at, it is possible to detect the presence or absence of foreign matter in the object to be inspected, particularly in the film to be inspected on the object to be inspected.

(3) Since weak light can be transmitted by making the object to be inspected a film to be inspected formed on a face plate which easily transmits light, it is possible to detect foreign matter independent of the light source. It will be possible.

(4). By detecting the object to be inspected by transmitting light having a wavelength longer than that of the optical system, even a small foreign matter can be detected, so that the detection probability can be improved.

(5). By controlling and detecting the detection sensitivity of the detection section installed on the back side of the inspection object, the type and transmittance of the inspection object or the inspection film, and the size and shape of the foreign matter. Since the detection sensitivity can be adjusted according to the situation, it is possible to perform detection with optimum detection accuracy.

(6) By virtue of the above items (1) to (5), especially when applied to the manufacture of a semiconductor integrated circuit device, it becomes possible to detect a foreign substance in a film to be inspected, whereby a pattern due to the foreign substance in the film can be detected. It is possible to prevent a short circuit defect and speed up feedback to the device when a foreign substance occurs.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram illustrating a foreign matter detection unit of a foreign matter inspection apparatus that is an embodiment of the present invention.

FIG. 2 is an internal configuration diagram showing a foreign matter inspection apparatus of the present embodiment.

FIG. 3 is an external view showing a foreign matter inspection device of the present embodiment.

FIG. 4 is a schematic configuration diagram showing a main part of a foreign matter inspection device that is an example of a conventional technique.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Wafer 2 Resist film 3 Light source 4 Light 5 Foreign matter 6 Light receiver 11 Inspected object 12 Optical system 13 Detection section 14 Transparent wafer (face plate-like object) 15 Resist film (Inspected film) 16 Foreign matter 17 Light 18 Light source 19 Optical sensor 20 Transport arm 21 Loader section 22 Unloader section 23 Display 24 Keyboard

Claims (5)

[Claims] 1. A foreign matter inspection apparatus for detecting a foreign matter in a face plate-like object to be inspected, the optical system irradiating the object to be inspected with light, and the light transmitted through the object to be inspected. And a detection unit, at the time of detecting foreign matter of the inspection object, the optical system transmits light from the main surface side of the inspection object,
A foreign matter inspecting apparatus, which detects a foreign matter by allowing transmitted light to be sensed by the detection unit installed on the back side of the inspected object. 2. The detection unit is installed on the main surface side and the back surface side so as to sandwich the inspection object with respect to the light of the optical system, and the detection unit installed on the main surface side and the back surface. The foreign matter inspection apparatus according to claim 1, wherein the foreign matter in the object to be inspected is detected by the intensity of transmitted light by a detection unit installed on the side. 3. The object to be inspected is a film to be inspected formed on a face plate which easily transmits light, and foreign matter in the film to be inspected is detected. Foreign matter inspection device. 4. A foreign matter detection method using the foreign matter inspection apparatus according to claim 1, wherein the foreign matter is detected by allowing light of a longer wavelength to pass through the optical system. A foreign matter detection method characterized by: 5. A foreign matter detection method using the foreign matter inspection apparatus according to claim 1, 2 or 3, wherein foreign matter is detected by controlling the detection sensitivity of a detection unit installed on the back side of the object to be inspected. A foreign matter detection method characterized by detecting.