JPH0648327Y2 - Film thickness measuring device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention relates to an apparatus for measuring a film thickness by utilizing light interference.

[Conventional technology]

To measure the film thickness of the measured object using the interference of light,
Light from a light source is projected onto an object to be measured, the transmitted light or reflected light is dispersed to detect interference fringes, and the film thickness of the object to be measured is measured. The structure of this interference film thickness meter is shown in, for example, Japanese Patent Laid-Open No. 63-50703 developed by the applicant.

[Problems to be solved by the device]

When the film thickness of a running film is measured by this interference film thickness meter, the film runs while being held between a number of pairs of rollers, so that irregular wrinkles occur.

When attempting to measure at this wrinkle portion, the projected light was reflected in an uncertain direction due to the wrinkles, and the apparent thickness was also uneven due to the wrinkles, and accurate measurement was not possible.

In view of the above points, an object of the present invention is to provide an interferometric film thickness measuring device which can eliminate the influence of wrinkles of the object to be measured and can accurately measure the film thickness of the object to be measured.

[Means for Solving the Problems]

In this invention, a detector projects light on an object to be measured, the transmitted light or reflected light is spectrally detected to detect interference fringes, and the film thickness of the object to be measured is measured. Air delivery means for delivering air to the site is provided.

[Action]

By the air feeding means, the wrinkles of the object to be measured are stretched and eliminated, so that the correct film thickness can be measured.

〔Example〕

FIG. 1 is a structural explanatory view showing an embodiment of the present invention.

In the figure, 1 is a detector, and this detector 1 is an object to be measured 2 such as a film that travels light through a half mirror 12.
A light source 11 for projecting light onto the object, a spectroscopic means 13 such as a diffraction grating for condensing the light transmitted or reflected by the DUT 2 again through a half mirror 12 and the like, and each wavelength dispersed by the spectroscopic means 13. The detection element 14 is composed of an image sensor such as a CCD for detecting the light, and the measuring means 15 for detecting the interference fringes from the output of the detection element 14 and measuring the film thickness of the DUT 2. In addition, this optical system shows an outline,
A condenser lens and the like on the way are omitted (see JP-A-63-50703).

A hood 3 as an air sending means is provided between the detector 1 and the object to be measured 2, and the light from the detector 1 is projected and received via an optical path in the hood. This hood 3
Is a substantially double cylinder, has a flange 3a formed at its tip, is supplied with air A from an air source 4, and air A rectified via an air permeation part 3b is the measurement site of the object 2 to be measured. It is sent to the vicinity of 2a and blown to it, and an appropriate force is applied to it, and the wrinkles at that part grow and disappear, making it possible to perform correct measurement without the influence of wrinkles. Further, the pressure of the air source 4 is indicated by the pressure gauge 5, and when the DUT 2 is damaged due to a hole or the like, the indicated value fluctuates and the damage can be known. Further, the pressure gauge 5 may be used as a regulator with a pressure gauge to constantly send air at a constant pressure.

FIG. 2 shows another embodiment, in which the object to be measured 2 of the detector 1 is
In the vicinity of the measurement site 2a of the above, at least one of the air sending means 7 is provided separately below the opposite side of the air sending means 6 or the object to be measured 2 with the detector 1 present. Measured object 2
The wrinkles may be eliminated.

[Effect of device]

In this device, air is blown to the object to be measured, so wrinkles on the object to be measured disappear, unevenness disappears, sufficient measurement light is obtained, and accurate measurement with an interferometric film thickness meter is possible. Becomes

[Brief description of drawings]

1 and 2 are configuration explanatory views showing an embodiment of the present invention. 1 ... Detector, 11 ... Light source, 12 ... Half mirror, 13 ...
… Spectroscopic means, 14 …… Detecting element, 15 …… Measuring means, 2 ……
Object to be measured, 3 ... Hood (air delivery means), 4 ... Air source, 5 ... Pressure gauge, 6, 7 ... Air delivery means, 3a ... Flange, 3b ... Air transmission part, 2a ... Measurement site

Claims (1)

[Scope of utility model registration request] 1. A detector for projecting light to an object to be measured, separating transmitted light or reflected light to detect interference fringes, and measuring a film thickness of the object to be measured, and a measurement site of the object to be measured. A film thickness measuring device, comprising: an air sending means for sending air to the film.