JPS61265515A - Method for measuring processing accuracy - Google Patents

Abstract

PURPOSE:To make it possible to measure the processing accuracy of 0.1mum or less of a pattern, by guiding light, which was deflected to the lateral direction of the pattern, to the pattern by using a grating to measure the power of scattered light. CONSTITUTION:Polymethyl methacrylic acid (PMMA) with a refractive index of 1.491 is applied to a quartz glass substrate 2 in a thickness of about 0.8mum to form a film 1. Next, PMMA is processed into a linear pattern with a line width of about 1.2mum and, thereafter, a grating 4 with a cycle of about 1mum is formed to the surface of PMMA. Helium/neon laser beam deflected to the lateral direction of the pattern is guided to PMMA in air through the grating 4 and the power P1 of scattered beam from the slit 6 placed on PMMA is measured. Next, the slit 6 is moved by about 4mm toward the grating 4 to measure the power P2 of scattered light from the slit 6. From the ratio of powers P1, P2, the distance between measuring points and the correlation between the shape of the film and the refractive index thereof, the disturbance of the pattern side wall is calculated to make it possible to measure processing accuracy of 0.1mum or less.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a method for measuring the machining accuracy of a pattern formed by microfabrication.

[Conventional technology]

Conventionally, the processing accuracy of a pattern obtained by microfabrication has been measured by observing the pattern using an optical microscope or a scanning electron microscope.

[Problem that the invention seeks to solve]

However, with this method, it is difficult to measure the entire machining accuracy of 0.1 μm or less.

An object of the present invention is to provide a machining accuracy measuring method that completely eliminates the above-mentioned drawbacks.

[Means for solving problems]

That is, in the present invention, the refractive index and processed line width on the substrate are known, the grating is formed on a turned transparent material film, and the light polarized in the width direction of the pattern is guided through the grating. The power value of the scattered light emitted from the wave and coating was measured separately at two measurement points, and the correlation between the ratio of each power value, the distance between the measurement points, the shape of the film, and the refractive index was calculated. This is a processing accuracy measurement method characterized by determining the disturbance of pattern sidewalls.

[Principle of the invention]

The present invention will be explained below with reference to all the drawings.

As shown in FIG. 1, when a film 1 processed to have a line width W with a refractive index n1 is sandwiched between a substrate 2 and a substance (for example, air or liquid) 3 with a refractive index no, first, A grating 4 is formed on the surface of the film 1. Next, the light 5 polarized in the width direction of the film 1 is guided into the film 1 through the entire grating 4, and the power PI k of the scattered light 7 emitted from the slit 6 placed on the film 1 is measured. . Next, the slit 6 is moved by a distance and the power Pzk of the scattered light 7 emitted from the slit 6 is measured. At this time, the disturbance a of the pattern sidewall is given by: Therefore, we measure Pi lP2 k,
By solving equation (1), the pattern sidewall disturbance & can be determined.

〔Example〕

Examples of the present invention will be shown below. A quartz glass entire substrate 2 is used, and a film 1 of polymethyl methacrylic acid (PMMA) with a refractive index of 1.491 is applied thereto to a thickness of 0.8 μm.
did. Next, after processing PMMA' into a linear pattern with a line width of 1 to 2 μm, a grating 4 with a pitch of 1 μm was formed on the surface of the PMMA. From air (refractive index 1.000), helium/neon led light f polarized in the width direction of the pattern is passed through the grating 4 and guided into the PMMA, and is emitted from the slit 6 placed on the PMMA. When the power of scattered light PI k was measured, its value was 18μ
It was W. Next, insert the slit 6 toward the grating.
When the power P2 of the scattered light emitted from the slit 6 was measured after moving by \4B, the value was 16 μW.

By substituting Pt and Pz into equation (1) and finding a, it was found that the processing accuracy of the PMMA pattern was 0.03 μm.

〔Effect of the invention〕

Therefore, according to the present invention, the processing accuracy of a pattern can be determined with high precision by simply guiding polarized light in the width direction of the pattern using a grating and measuring the power of the scattered light. It has the following.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram showing a method for measuring processing accuracy after processing a film. l...film, 2...substrate, 3...substance with refractive index nQ,
4... Grating, 5... Light polarized in the width direction of the film (glossy turn), 6... Slit, 7... Scattered light.

Claims (1)

[Claims] (1) A grating is formed on a patterned transparent material film with a known refractive index and processed line width on a substrate, and light polarized in the width direction of the pattern is guided through the grating, and the film is The power value of the scattered light emitted from the is measured separately at two measurement points, and the disturbance of the pattern sidewall is determined from the correlation between the ratio of each power value, the distance between the measurement points, the film shape, and the refractive index. A machining accuracy measurement method characterized by determining .