CS244094B1 - Method of measuring records on photochemical materials - Google Patents

Abstract

The solution concerns the measurement of records on photochemical materials, especially in photoresist layers, especially when measuring their properties and when evaluating the results of technological operations. When measuring similar records, it is usually necessary to measure the thickness of the layer of the processed photochemical material, or differences in thickness. The devices used are expensive and the measurement is often time-consuming. The essence of the invention is to utilize the fact that the distribution of light intensity in diffractograms, resulting from the bending of light on equidistant image elements, changes significantly when the thickness (or absorption) of these image elements changes. ' In the process according to the invention, a pattern containing equidistant elements is exposed to a layer of photochemical material, the exposed material is processed and the resulting image is inserted into a diffractometer. The values characterizing the intensity of the radiation in the diffraction maxima belonging to equidistant image elements are measured (especially the values proportional to these intensities or their logarithms) and the height of the relief formed by the image elements, or alternatively the height of this relief, is determined by numerical calculation. The advantages of the method according to the invention are the possibility of measuring even very small thicknesses of image records relatively quickly and using less expensive equipment.

Description

The solution relates to the measurement of records on photochemical materials, especially in photoresist layers, especially when measuring their properties and in evaluating the results of technological operations. When measuring similar records, it is usually necessary to measure the layer thickness of processed photochemical material or differences in thickness. The present invention is based on the fact that the distribution of the light intensity in diffraction patterns resulting from the bending of light on equidistant pixels changes substantially as the thickness (or absorption) of these pixels changes. '

In the process of the invention, a pattern containing equidistant elements is exposed to a layer of photochemical material, the exposed material is processed and the resulting image is inserted into a diffractometer.

The values characterizing the intensity of radiation in the bending maxima corresponding to the equidistant elements of the image (in particular the values proportional to these intensities or its logarithms) are measured and the height of the relief formed by the pixels or the numerical sequence is determined. I alternates this relief. The advantages of the process according to the invention are that it is possible to measure relatively fast and, with the use of a less expensive apparatus, very small film thicknesses.

244 094

244 094

The invention relates to the measurement of records on photochemical materials, in particular in photoresin layers, in particular for measuring their properties and for evaluating the results of technological operations

Some photochemical materials, especially photoresists, provide, after irradiation and subsequent processing in a suitable gaseous or more often liquid medium (the so-called developer), an image formed by areas whose thickness depends on the irradiation. In practice, the most common cases where the recording is part of the exposed area are part of the area covered with a layer of processed photochemical material; These layers require a substrate during etching, etc. When measuring the properties of these materials (especially eensitometric and microsensitometric) and further in technological applications, it is necessary or expedient to measure the thickness of the layers resulting from the processing of photochemical material, respectively. thickness differences at differently exposed locations. In particular, mechanical, interferometric and ellipsometric methods are used for this purpose. The equipment required is generally complex and expensive, and measurement is usually time consuming. It is particularly difficult to measure layers with a very small thickness (eg several tenths of a micrometer or less).

These drawbacks have no process according to the invention, which is based on a process which makes it possible to take advantage of the fact that the distribution of the intensity of radiation in diffraction patterns produced by light bending on equidistant pixels changes substantially as the thickness (or absorption) of these pixels changes.

Advantages of the process according to the invention lie in particular in that a relatively simple and inexpensive diffractometer is sufficient for carrying out the process and that the measurement and evaluation of the measurement results are sufficient.

244 094 is fast. Automated procedures can be used for measurement and evaluation. The method according to the invention is particularly suitable for measuring small thicknesses or differences in thickness.

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When measuring the recording produced in the return of the photochemical material on the support and by actinic radiation on the material layer, a pattern containing an array of equidistant elements is exposed. For this purpose, either a special test pattern (eg sensitometric measurement; a pattern consisting of a set of parallel light and dark lines) is particularly suitable, or a pattern used for the technological operations to be controlled, etc. (if the pattern itself contains equidietate elements, or it is possible to include such elements for measurement). The irradiated material is processed in the manner prescribed or selected for it, and the mat and the resulting recording are placed in a diffractoreter. It measures the values (absolute or relative) of the intensity of the radiation at the diffraction maxima corresponding to the equidistant pixels. These a and m values may be a measure of the result achieved (e.g., in determining whether a repetition of a technological operation has yielded a consistent result) or determining the thickness (height) of the relief forming the record or the same duty cycle of that relief. The measurement of the dependence of the relief height on the exposure or its logarithm is characterized by the aensitometric properties of the measured photochemical material, the analogous dependence of the duty cycle contains information on the microaensitometric properties of the material.

The process according to the invention can be used in particular for measuring the swelling of photochemical materials and for evaluating the properties of records made from these materials, in particular for measuring the thickness of photoresin masks and the like, for checking and optimizing technological processes. The method of the invention can also be used to measure records on materials that respond to changes in exposure by changes in light absorption. Here, the procedure can be used especially for measuring and sorting of images of equidiant elements in evaluation of microaensitometric properties of materials.

Claims (1)

SUBJECT OF THE INVENTION 244 094 Method for measuring recordings on photochemical materials, characterized in that an image containing equidistant pixels is exposed to a layer of photochemical material by actinic radiation, after recording the exposed layer of photochemical material, the recording is placed in a diffractometer and elements.