JPH06118010A - Foreign matter inspection device and pellicle - Google Patents

Abstract

(57) [Abstract] [Purpose] In a foreign matter inspection device for inspecting foreign matter on a reticle used in the semiconductor device manufacturing process, foreign matter detection sensitivity corresponding to the pellicle type when the pellicle is attached to the reticle surface. Is set automatically. [Structure] A foreign matter inspection device is equipped with a pellicle detection sensor,
Recognize the type of foreign matter inspection device and pellicle film, etc., which has a function of multiplying the foreign matter size by a preset correction coefficient according to the degree to which the foreign matter detection sensitivity changes depending on the pellicle film, and other pellicle size, type A pellicle that has markings and symbols for marking on the side of the pellicle frame. [Effect] When the pellicle is attached to the reticle surface, the foreign matter detection sensitivity corresponding to the pellicle type is automatically set to prevent the foreign matter inspection work from being mistaken and to omit the complicated sensitivity setting work. .

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an inspection apparatus for inspecting foreign matter adhering to the surfaces of photomasks, reticles and the like used in semiconductor device manufacturing processes and the like.

Further, the present invention relates to a frame of a pellicle which is attached to prevent the attachment of foreign matter to the surface of a photomask, reticle or the like.

[0003]

2. Description of the Related Art For inspecting foreign matter adhering to the surface of a mask or reticle, a laser beam is radiated onto the mask or reticle surface obliquely from above, and the laser light scattered by the foreign matter is collected and converted into a current by a photomultiplier tube. It is common practice to convert the intensity of the electric current into a foreign substance size by a conversion factor determined in advance and display it as a foreign substance adhering to the reticle surface.

[0004]

However, according to the conventional method, when a mask or reticle surface is coated with a pellicle for preventing foreign matter from adhering, the pellicle film is not attached because the laser beam transmitted through the pellicle film is detected. Compared with the case, the intensity of scattered laser light changes (a few fractions to a few hundredths) due to transmission through the film, resulting in an error in measuring the particle diameter of a foreign substance.

[0005]

SUMMARY OF THE INVENTION The present invention has been made to solve the above-described problems, and automatically detects whether or not a pellicle is attached to a measurement reticle, and when the pellicle is attached. In order to have a function of converting the measured foreign matter size by a preset correction coefficient and converting it to a more accurate foreign matter size, various information should be entered on the pellicle frame. This has been achieved by providing the foreign substance inspection device with a function of reading the information and having a database of the information in the foreign substance inspection device.

[0006]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows a schematic view of the mechanism of an inspection section of a defect detection section of a foreign matter inspection apparatus adopting the method of the present invention.

In the figure, 1 indicates a reticle to be inspected, 6 is a pellicle film made of cellulose or the like which is stuck, 2 is a pellicle frame of the stuck pellicle, 3 is a He-Ne laser light source which is scanned on the reticle surface 4 is a scattered light detector for detecting laser light scattered by foreign substances attached to the surface of the reticle and pellicle film, 5 is a reticle frame detector which also serves as a barcode reader, and 7 is a laser which is irradiated by 3 and reflected straight. It shows light, and the straight part of the laser light is considered to be emitted to the outside so that it does not enter the scattered light detector.

The laser light is scanned in the XY directions on the reticle surface and scattered by the foreign matter on the reticle surface, but only the scattered light is detected by the photomultiplier tube in the scattered light detector 4 and the intensity of the laser light is changed. Detected as foreign matter.

At the same time that the foreign matter is detected, the foreign matter detection position and the foreign matter size are recorded by associating with the scanning position of the laser beam.

Here, when the pellicle is not attached to the reticle, the detected scattered light intensity is converted into a foreign matter size according to a preset conversion coefficient, but when the pellicle is attached, the laser light is changed. When passing through the pellicle film of 6, the amount of scattered light is attenuated as compared with the case where there is no pellicle film due to attenuation and scattering, so the conversion factor of the scattering intensity to the foreign matter size used when there is no pellicle is used as it is. And it is not possible to calculate the foreign matter size accurately.

Here, a sticker on which a pellicle film type (film thickness, presence / absence of an antireflection film), a frame size, and the like is written using a bar code on the side surface of the pellicle frame which has not been conventionally used. It was stuck in place.

Further, the foreign matter inspection device is provided with a reticle frame detector 5 which also serves as a bar code reader, and detects the pellicle frame attached to the reticle and the presence / absence of a pellicle written on the side surface of the pellicle, frame size, pellicle type, etc. It is equipped with a function of sending the above information to the main body of the foreign substance inspection device.

A storage device such as an IC memory for accommodating a database for the above information is provided in advance in the foreign matter inspection device, and a bar code indicating a pellicle film type (film thickness, presence or absence of antireflection film), frame size, etc. Also, information necessary for foreign matter inspection such as a correction coefficient, an inspection area, and an inspection mode corresponding thereto are stored.

The pellicle frame reader 5 having a function as a bar code reader first reads the presence / absence of a pellicle and the above information, and then calculates the pellicle film type in advance for each pellicle type. By selecting the scattered light attenuation coefficient input to the storage device based on the bar code information from the pellicle frame reader, and calculating it using an appropriate correction coefficient when converting the scattered light intensity into the foreign matter size. Therefore, it is possible to automatically convert to a more accurate foreign substance size without human intervention.

Further, by automatically obtaining the frame size from the above information, the optimum inspection area is automatically set without human intervention.

Further, the information from the pellicle frame reader should not only be used for calibrating the defect detection sensitivity, but should be rejected as inspection mode (reticle, pellicle surface inspection), inspection area setting, and defect. It is also effective for other purposes such as setting the size of foreign matter.

[0017]

As a result of using the foreign matter inspection apparatus employing the method according to the present invention and the pellicle, it is not necessary to re-input the defect detection sensitivity of the foreign matter inspection apparatus depending on whether or not the pellicle is attached to the reticle to be inspected. , The defect size can be displayed accurately even if the reticle using different pellicle types such as film thickness is continuously inspected.
Labor saving of inspection work and improvement of accuracy were achieved.

Also, it is effective for automatic setting of other inspection conditions such as inspection mode (inspection of reticle and pellicle surface) and inspection area at the time of foreign substance inspection, which greatly contributes to efficiency of inspection work. It was something to do.

[Brief description of drawings]

FIG. 1 is a schematic view of the mechanism of an inspection unit of a foreign matter inspection device that employs the method of the present invention.

[Explanation of symbols]

 1 Reticle 2 Pellicle Frame 3 Laser Light Source 4 Scattered Light Detector 5 Pellicle Frame Reader 6 Pellicle Film 7 Reflected Laser Light

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Claims (2)

[Claims] 1. A pellicle for preventing foreign matter from adhering to a pattern surface on a reticle in a foreign matter inspection apparatus for measuring fine foreign matter deposited on a substrate such as a reticle used in the manufacturing process of semiconductor devices and the like. Equipped with a sensor that detects whether or not is attached, and when a pellicle is attached, the foreign matter size is multiplied by a preset correction coefficient according to the degree to which the foreign matter detection sensitivity changes due to the pellicle film. A foreign matter inspection device and a pellicle having a function. 2. A pellicle film type, other reticle types, pellicle size, marks and symbols for recognizing the type, etc. are written on the side surface of the frame, and information regarding the pellicle is read at the time of foreign matter inspection, and inspection conditions and correction coefficients are read. A foreign matter inspection device and pellicle characterized by automatically setting the etc.