JPH0527939B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to an apparatus for observing foreign matter on a substrate surface, which can be used in a vacuum process apparatus such as a vacuum apparatus for semiconductor manufacturing.

BACKGROUND ART For example, in semiconductor manufacturing technology, it is important to observe and inspect foreign substances such as dust particles attached to the surface of a substrate such as a wafer from the viewpoint of improving yield.

Conventionally used methods for observing foreign matter on the surface of a substrate include: (1) Using light such as a laser beam to detect the particle size of the foreign matter from the scattered light; (2) Using a microscope. (3) A method of observing the shape of a foreign object using a scanning electron microscope.

Since the first optical method measures the intensity of scattered light, the actual shape and size of the foreign object cannot be determined. Scattered light naturally varies depending on shape and often provides misleading information. Observation using the second microscope can only be used in the atmosphere, and it is difficult to use it during the process. Furthermore, it takes time to search for foreign matter, and detection of submicron particles is difficult. In the third method, a scanning electron microscope can observe the shape and size of foreign particles on the spot in a vacuum, but it is difficult to detect submicron particles (for example, 10 particles or less on a 5-inch wafer).
This method requires a huge amount of time and is not suitable for use in a process line.

Problems to be Solved by the Invention As described above, conventional optical methods only detect the intensity of scattered light and have the disadvantage of not being able to identify the actual particle size of foreign particles. This method has the disadvantage that it is difficult to use in the middle of the process because it can only be used in the atmosphere, and it takes time to detect foreign substances.
Furthermore, the method using a scanning electron microscope requires a considerable amount of time to detect submicron particles, so there is a problem that it cannot be practically used in a process line.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide an apparatus for observing foreign matter on a substrate surface that uses a combination of a laser beam and a scanning electron microscope to easily and quickly observe foreign matter on the spot in a vacuum process line. be.

Means for Solving the Problems In order to achieve the above object, a foreign matter observation device on a substrate surface according to the present invention includes a laser foreign matter position detection device and a scanning electron microscope, and the laser foreign matter position detection device has a laser foreign matter position detection device. , the laser beam introduced onto the substrate surface inside the vacuum chamber through the laser beam introduction vacuum window provided in the vacuum chamber is
It is equipped with a laser scanner that scans in the Y direction and a detector placed at a position where it can detect the laser beam diffusely reflected by foreign objects on the substrate, and the vacuum vessel is equipped with a laser beam that is specularly reflected on the substrate and guided to the outside. A vacuum window for guiding the laser beam is provided, and the substrate is placed on a movable table that can move in the X and Y directions.The position of the movable table is controlled according to the foreign object detection signal detected by the detector, and the substrate is It is characterized by being able to move relative to the scanning electron microscope.

Function In the apparatus for observing foreign matter on a substrate surface according to the present invention configured as described above, a laser beam is introduced onto the substrate surface inside the vacuum container through the vacuum window for introducing the laser beam provided in the vacuum container, and the laser beam is introduced onto the substrate surface inside the vacuum container. The light beam scans the surface of the substrate in the X and Y directions. If there is any foreign matter on the surface of this board,
The introduced laser beam is specularly reflected on the substrate and is not led out through the laser beam guiding vacuum window, and the portion of the laser beam that collides with the foreign object is diffusely reflected and enters the detector. Thereby, the detector detects where on the substrate surface the foreign matter is present. A foreign matter position detection signal detected by the detector is supplied to a drive control device for a movable table on which the substrate is placed, and the movable table is thereby moved to position the foreign matter on the substrate in the field of view of the scanning electron microscope. As a result, the shape, size, etc. of the foreign matter on the substrate can be observed using a scanning electron microscope. This series of foreign matter observation operations can be performed while the device is in the vacuum process line.

Embodiments Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.

The drawing shows the configuration of an apparatus for observing foreign matter on the surface of a substrate according to the present invention, in which 1 is a vacuum container, and this vacuum container 1 is provided with a movable table 2 that can move in the X and Y directions. A substrate holder 3 is attached on top, and a substrate 4 is mounted on it. The vacuum container 1 includes a vacuum window 1a for introducing a laser beam provided at a position where the laser beam can be introduced at a predetermined angle of incidence onto the substrate 4, and a laser beam that enters the substrate 4 through the vacuum window 1a for introducing the laser beam. A vacuum window (not shown) for guiding the laser beam is provided at a position where the light beam is specularly reflected and proceeds. Further, in the illustrated embodiment, a scanning electron microscope 5 is disposed in the vacuum vessel 1 at a position opposite to the substrate 4. Reference numeral 6 denotes a laser beam generation/introduction device attached to the laser beam introduction vacuum window 1a, and a scanner 7 that scans the laser beam on the substrate 4 in the X and Y directions.
It is equipped with On the other hand, a detector 8 is attached to the vacuum vessel 1 at a required angle with respect to a plane passing through the laser beam generation/introduction device 6, the vacuum window 1a for laser beam introduction, and the vacuum window for laser beam extraction. The detector 8 is connected via an amplifier 9 and an interface 10 to a computer arrangement 11 . The scanner 7 is connected to a scanner control device 12, and this scanner control device 12 is connected to an interface 13.
It is connected so that its operation is controlled by a computer device 11 via. Further, the computer device 11 is connected via an interface 14 to a drive control device 15 that controls the drive of the movable table 2, and controls the operation of the drive control device 15.

In the operation of the illustrated device configured in this way,
First, a laser beam generated by the laser beam generation and introduction device 6 is scanned by the scanner 7, and the substrate 4 on the movable table 2 is scanned in the X and Y directions through the laser beam introduction vacuum window 1a. If there is no foreign matter on the substrate scanned by the laser beam, the laser beam is specularly reflected by the substrate and exits the vacuum chamber 1 through a vacuum window for guiding the laser beam (not shown).
However, if there is a foreign object on the substrate, the part of the laser beam that collides with the foreign object will be scattered, and this scattered light will be detected by a detector 8, which will provide an output signal via an amplifier 9 to a computer device 11, The position of the foreign object on the substrate 4 is memorized. After the scanning by the laser beam is thus completed, the computer device 11 supplies the foreign object position signal to the drive control device 15 that controls the drive of the movable table 2 via the interface 14, and drives the movable table 2 to place the foreign object position signal on the substrate. A foreign object is brought into the field of view of the scanning electron microscope 5. In this way, the shape, size, etc. of foreign particles on the substrate can be observed using the scanning electron microscope 5.

In the illustrated embodiment, the scanning electron microscope 5 is placed directly above the substrate 4, but the scanning electron microscope 5 may be placed at any position where foreign matter on the substrate can be observed. Further, the position of the detector 8 may be any position as long as it can detect light diffusely reflected by foreign matter on the substrate. Furthermore, although the movable table 2 is attached to the outside of the vacuum container 1 in the illustrated embodiment, it may be provided inside the vacuum container 1 and driven from the outside if necessary.

Effects of the Invention As explained above, in the apparatus for observing foreign matter on the surface of a substrate according to the present invention, by combining means for detecting the position of foreign matter on the substrate using a laser beam and a scanning electron microscope, it is possible to It can be easily incorporated into line vacuum equipment, such as manufacturing equipment, where in-situ observation has been difficult, and the accurate position, shape, size, etc. of foreign objects can be detected and observed faster than conventional methods. I can do it. Furthermore, since the foreign matter observation device on the substrate surface according to the present invention can observe the shape of the foreign matter, it is possible to infer the source of the foreign matter. For example, if the foreign matter originates from a vacuum device, the source of the foreign matter can be estimated. , it is possible to set a guideline for equipment maintenance timing, etc., and as a result, product yield can be improved.

[Brief explanation of the drawing]

The drawing is a schematic diagram showing the configuration of an apparatus according to an embodiment of the present invention. In the figure, 1... vacuum container, 2... movable table,
4...Substrate, 5...Scanning electron microscope, 6,7,
8...Laser foreign object position detection device.

Claims (1)

[Claims] 1 having a laser foreign matter position detection device and a scanning electron microscope, wherein the laser foreign matter position detection device detects a laser beam introduced onto the substrate surface inside the vacuum container through a vacuum window for laser beam introduction provided in the vacuum container; The vacuum chamber is equipped with a laser scanner that scans the substrate surface in the X and Y directions, and a detector placed at a position where it can detect the laser beam diffusely reflected by foreign matter on the substrate. A vacuum window for guiding the reflected laser beam to the outside is provided, the substrate is placed on a movable table that can move in the X and Y directions, and the movable table is moved in response to the foreign object detection signal detected by the detector. An apparatus for observing foreign matter on a surface of a substrate, characterized in that the substrate is moved relative to the scanning electron microscope by controlling the position of the substrate.