JP2000009669A - Inspection apparatus for surface property of object to be inspected - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an inspection apparatus, for a surface property, by which the abnormality of a wide-range, extremely small and extremely faint irregular surface property is detected with high sensitivity so as to be capable of being recorded as surface information. SOLUTION: An inspection apparatus for the surface property of an object 10 to be inspected is featured in such a way that a dew-point hygrometer 6 which measures the dew point of the ambient atmosphere of the object 10 to be inspected, placed on a cooling stage 1 is provided and that the cooling stage 1 which makes the temperature of the object 10, to be inspected, variable with reference to the dew point of the ambient atmosphere is provided. In addition, the inspection apparatus is featured so as to be provided with a camera 21 which images the object 10, to be inspected, placed on the cooling stage 1. In addition, the inspection apparatus is featured so as to be provided with a very-small-rough-surface detecting device 21 which uses the principle of a magic mirror capable of detecting the surface state of the object 10, to be inspected, placed on the cooling stage 1.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for inspecting the surface properties of a semiconductor wafer, a glass substrate for liquid crystal, etc., such as unevenness of cleaning, contamination, and abrasion, on the basis of the state of dew condensation on the surface of the object. The present invention relates to a surface property inspection device.

[0002]

2. Description of the Related Art In a semiconductor manufacturing process, an abnormal surface property such as cleaning unevenness, contamination unevenness, and scratch unevenness on a semiconductor wafer surface has a great adverse effect on product performance and yield. Therefore, the inspection of dirt and scratches is performed with submicron accuracy, and an optical inspection device that observes light scattering of a defective portion using laser light or UV light and an automatic defect inspection device using image processing technology related thereto. Is supported. In addition, elemental analysis of the detected attached foreign matter and the like has become possible even for an extremely small area.

As an inspection method different from the above, there is a method of exposing to the surface of an object to be inspected. That is, when the test object is exposed to water vapor generated from a heated water surface in the container and is exposed to the surface of the test object, the surface condition of the test object (cleaning unevenness, contamination unevenness, scratch unevenness, etc.) causes the exposure. The contact angles and the sizes of the condensed liquids are different, and the appearance of the dew surface is different. There is known a method of inspecting unevenness (non-uniformity) of surface properties by observing the state. For example, "Surface Chemistry of Glass" (Shoji Dohashi, Nanedo, published in 1956), "Physical Chemistry of Glass Surface" (Shoji Dohashi, Kodansha, published in 1974), and Japanese Patent Application Laid-Open (A) Hei 2 -168150, JP-A-6-43127, JP-A-7
181468.

A conventional example will be described with reference to FIG. Container 31
And water is heated by the heater 33 until steam 35 is generated. Next, the test object 3 is placed above the water 32.
When the inspection surface of the inspection object 34 is exposed to the water vapor 35 generated by positioning the position 4, if the surface temperature of the inspection object 34 is lower than the dew point of the water vapor 35, the surface exposed to the water vapor 35 is exposed. The result occurs. The contact angle and size of the condensed liquid vary depending on the surface properties of the inspection object 34, and as a result, the appearance of the dew surface varies, resulting in uneven cleaning, contamination, and scratches on the surface of the inspection object 34. Abnormalities in surface properties such as unevenness can be detected with high sensitivity. However, the particles of the water vapor 35 generated by the above-described method are large, ranging in size from several μm to several tens μm. When water vapor droplets having such a large particle diameter are condensed and adhere to the surface of the inspection object 34, it becomes difficult to detect a surface abnormality finer than this particle diameter,
The detection sensitivity is also low. In this way, the inspection object 3
The observation of the dew surface 36 generated on the surface of 4 is performed by the observer 39 by irradiating the illumination light 38 of the illumination device 37.
When the inspection object 34 is transparent, as shown in FIG.
Observation is made from the back side of the sample No. 4. The observation result is sketched and recorded by the observer 39 based on the observation memory.

[0005]

According to the inspection method using the above-mentioned automatic defect inspection apparatus, the dimensional accuracy for detecting foreign matters, scratches and pinholes on a substrate or a wafer is quite good. It is difficult to cope with the detection of surface information in the case of surface contamination such as cleaning unevenness or organic contamination unevenness. On the other hand, the above-described inspection method based on dew condensation can solve such a problem to some extent, but it is difficult to cope with the case where the irregularity of the surface texture is extremely small and extremely weak.
The present invention has been made under such circumstances, and it is possible to easily and highly sensitively detect a wide range of extremely minute and extremely weak irregular surface irregularities with high sensitivity, and to record image information in detail without relying on manual sketching. It is to provide a device.

[0006]

SUMMARY OF THE INVENTION The present invention provides a method for easily detecting, with high sensitivity, an extremely minute and extremely weak irregular surface texture of a test object, and detecting the detected abnormality of the surface texture. The present invention relates to an apparatus for recording as surface information.
With the conventional dew condensation method, the detection accuracy is insufficient because the dew particles are too large or unstable, and the recording of surface texture abnormalities can be recorded in detail because it is manually sketched. Absent. As means for solving the problem, a dew point meter for measuring the dew point of the ambient atmosphere of the device under test, a cooling stage for varying the temperature of the device under test with respect to the dew point, and a device mounted on the stage Surface property inspection characterized by comprising a camera for imaging the inspection object, or a micro-rough surface detection device using the principle of a magic mirror capable of detecting the surface condition of the inspection object instead of the camera Device.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described in detail with reference to FIGS. The cooling stage 1 is an application of a Peltier element, and the temperature of cooling and heating can be easily controlled by an electric current. A temperature sensor 2 for measuring the temperature is buried in the cooling stage 1 and measured by a thermometer 3, and a thermometer output 4 is input to a stage temperature controller 5. On the other hand, a dew point meter 6 for measuring the dew point of the atmosphere around the inspection object 10 is installed near the inspection object 10, and an output 7 of the dew point meter is input to the stage temperature controller 5. The stage temperature controller 5 controls the temperature of the cooling stage 1 by a controller output 8 in accordance with a cooling / heating program so that the temperature of the inspection object 10 substantially matches the dew point of the surrounding atmosphere.
By doing so, the dew surface 1
1 is formed. A heat conduction buffer 9 is provided between the cooling stage 1 and the test object 10 to improve heat conduction efficiency.

When the temperature of the cooling stage 1 on which the condensation surface 11 is formed is set to the condensation temperature, or when the temperature is slightly increased or decreased from that temperature, the condensation surface 11 disappears or is generated. By observing the transient state of the dew condensation state, it becomes possible to detect surface properties that cannot be detected in the steady state of dew condensation. The state of the dew surface 11 generated in this manner is based on the illumination light 2 from the lighting fixture 22 installed above the test object 10.
3 is illuminated and observed by the observer 24, and the state of the dew surface 11 is imaged and recorded by the camera 21.
Further, when the micro-rough surface detecting device 21 using the principle of the magic mirror is used instead of the camera, the state of the dew surface 11 is detected as an enhanced image, and the detection sensitivity is significantly improved. Also,
The image can be recorded as surface information. In this way, extremely small and very weak irregularities in the surface properties (cleaning unevenness, contamination unevenness, scratching unevenness) on the entire surface of the inspection object can be easily detected with high sensitivity, and the surface information can be manually sketched. It is possible to record in detail without depending.

[0009]

According to the present invention, a dew point meter for measuring the dew point of the surrounding atmosphere of a device under test and a cooling stage capable of varying the temperature of the device under test with respect to the dew point are provided. Dew condensation of submicron or less can be generated on the entire surface of the inspection object, which has the effect of easily detecting, with high sensitivity, extremely minute and extremely weak irregularities in the surface property of the entire inspection object surface. . Further, by providing a camera for imaging the surface of the inspection object placed on the cooling stage, there is an effect that the detected abnormality of the surface property can be recorded as surface information. Furthermore, instead of a camera, a micro-rough surface detector that uses the principle of a magic mirror that can detect the surface condition of the object to be inspected is provided, so that surface information that emphasizes abnormal surface properties can be detected. There is an effect that the detection sensitivity is remarkably improved and the detection sensitivity can be recorded.

[Brief description of the drawings]

FIG. 1 is a sectional view of a surface texture inspection apparatus according to an embodiment.

FIG. 2 is a sectional view of a conventional surface texture inspection apparatus.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Cooling stage 2 Temperature sensor 3 Thermometer 4 Thermometer output 5 Stage temperature controller 6 Dew point meter 7 Dew point meter output 8 Controller output 9 Heat conduction buffer material 10 Inspection object 11 Dew surface 21 Camera or micro rough surface detector 22 Lighting Instrument 23 Illumination light 24 Observer 31 Container 32 Water 33 Heater 34 Inspection object 35 Water vapor 36 Dew surface 37 Lighting fixture 38 Illumination light 39 Observer

Claims (3)

[Claims] A dew point meter (6) for measuring a dew point of an ambient atmosphere of an object (10) mounted on a cooling stage (1).
And a cooling stage (1) for varying the temperature of the test object (10) with respect to the dew point of the surrounding atmosphere. 2. A device for inspecting the surface properties of an object to be inspected according to claim 1, further comprising a camera for imaging the object to be inspected mounted on the cooling stage. 3. A micro-rough surface detecting device (21) using the principle of a magic mirror capable of detecting a surface state of an inspection object (10) mounted on a cooling stage (1). The surface texture inspection device for an object to be inspected according to claim 1, wherein: