JPS60236004A - Measuring method of line width - Google Patents

Abstract

PURPOSE:To determine exactly the width of a working line by emitting the spectra of the light made incident on the light transmittable material film on a substrate through a prism from another prism, determining the refractive index and thickness of the film and making the similar measurement after working. CONSTITUTION:Light 5 is made incident via a prism 4 on the thin film 1 consisting of the light transmittable material coated on the substrate 2 and the light separated to the spectra is emitted from the prism 6, by which the thickness and refractive index of the film are determined. The width of the film 1 is worked to a desired shape and thereafter the refractive index is determined by making the measurement similar to the above-mentioned measurement. The line width of the thin film is determined from the change in the refractive index. The line width of the pattern is thus exactly determined simply by measuring the exit angle of the light projected to the pattern before and after working.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a method for measuring the line width of a pattern processed by microfabrication.

(Prior art and its problems) Conventionally, K, which measures the line width of the notaturn obtained by microfabrication, irradiates condensed light from above the notaturn, and...!
This has been done by determining the reflectance of light from each part of the turn. However, the reflectance of light is so low! There was a drawback that the measured value of the 9-turn line [11] obtained for this reason was not equal to the 9-turn line width of the storm. ) An object of the present invention is to eliminate the above-mentioned drawbacks and provide a nine-line width measuring method.

(Structure of the Invention) That is, the present invention allows light guided through a prism to a light-transmitting material film on a substrate to be emitted from the line film through the prism, and the line film is determined based on the measured values of the emission angles of the light having different wavelengths. After determining the refractive index and film thickness of the film and processing these values into the desired shape, the processed wire film is passed through a prism to produce four waves of light, and then the light is emitted from the film through the prism. [7] Line [1] measurement method is characterized in that the processing line width of the processed film is determined by calculating the measured value of the emission angle of the light.

(Effects of the present invention/original details) The principle of the present invention will be explained below with reference to the drawings.

As shown in FIG. 1, a film 1 having a refractive index n4 and a thickness t is mixed with a material 2 having a refractive index n2 and a refractive index n. When the light 5 of the wavelength λ1 and the light 5 in the film 1 are sandwiched between the film 1 and the film 1, the light 5 with the wavelength to guide the wave.

Next, the prism 6 with a refractive index of n placed on the film l is d to emit light, and the emission angle θ11 of the light from the prism 6 is measured. Note that np+np are both n. .

It is necessary that it be larger than n2. At this time, the relationships of equations (1) to (4) hold between each variable regarding the TE wave.

β1 ” k I n p 8tnθ, 1...
(2) k, = 2π/λ1 ...... (3) no/
n p ” sin (θ2.-α)/s stone θ, ,
==-(41 However, α is the angle between the potential output I of the prism and the surface where 1 rhythm touches horizontal 1.

Furthermore, for TM waves, the equations (2), z, and (5) hold true.

Next, the light 5 with a wavelength λ2 is guided into the film 1 through the prism 4, and the light is emitted through the prism 6 at a light exit angle θ1.
Measure 2.

At this time, for the TE wave, between each variable, Take (6) to (
9) holds true.

(S) (O) 2np sin θP 2 on β2- (7) k2-
2π/λ2 ・・・・・・(8) no/n p”
s stone (θP2-α)/5IrIθI2 ・Song-(9)
Further, regarding the TM wave, the relationship 00 holds from equation (7).

Therefore, using light of different wavelengths, the emission angle θ14. After measuring θ12 from time to time, formula (1)
By solving (4) or equations (2) to (5), and equations (6) to (9) or equations (7) to (1), the refractive index n of the film 1, and (5) ( 4) Add thickness t.

Next, as shown in FIG. 2, when the light 5 is guided through the prism 4 through the film 1 processed into a line 11'', the light 5 is emitted through the prism 6. The light emission angle θ1 from this prism 6 is measured. At this time, regarding the TE wave,
From the formula 0υ, 0 carrier holds true.

Also, regarding TM waves, 01G is obtained from equation 03, and there are 31.

(6) By solving θQ from equation U or equation 01, one step width W of P turn can be calculated.

(Example) Examples of the present invention are shown below.

Polymethyl methacrylic acid (PMMA) is coated on quartz glass with a refractive index of 1.46, and air (refractive index 1.000
) Wavelength 63 throughout the heavy crown glass prism from inside
28X helium neon laser light? ! - When the light was guided in PMMA and the double crown with a refractive index of 1.587 set the output angle of the light emitted from the Las prism (α-45°) to 11, the output angle of the TE wave was 4o, t3+t. Ta.

In addition, as with all helium neon LED light with a wavelength of 11,523X, a waveguide was set, and the output angle at TEθ was set at 61 degrees, which was 38.42 degrees. Therefore, from equations (1) to (4) and equations (6) to (9), the film thickness of PMhlA is 1.6
μm, and the refractive index is 1.49. Next, PMMA'i
1j4Jc, after being processed into 9 turns, helium neon led light with a wavelength of 6328X was passed through a single weight round glass prism (t-)) into MMA, and the output angle of the light emitted from the heavy crown glass prism was measured. , Ta
The emission angle of the 1c wave was 25.37 degrees. Therefore, by requesting from 200 to 04, PMM after processing
It was found that the line 11t of the A-e turn was O5 μm.

(Effects of the Invention) Therefore, according to the present invention, the line width of the main turn can be determined accurately by simply measuring the emission angle of the light projected onto the prism in the nine turns before and after processing. It has a benefit.

[Brief explanation of drawings]

FIG. 1 is a schematic diagram showing a method for measuring the total refractive index and thickness of a film, and FIG. 2 is a schematic diagram showing a method for measuring the line width after processing of the film. l... Film, 2... Substance with refractive index ns, 3... Substance with refractive index IJ1, 4... Incident prism, 5... Light,
6... Output prism. (9)

Claims (1)

[Claims] (1) Guide the light through a prism through a translucent material on the substrate, and emit the light from the line film through the prism,
Determine the refractive index and film thickness of the film from the measured values of the emission angle of light of different wavelengths, process these values and the wire film into the desired shape, and then pass the light through a prism through the processed wire film. A method for measuring lines in a line, which is characterized in that the processed line width of the processed film is calculated by guiding the wave, and then calculating the measured value of the emission angle of the light emitted from the line film through a prism.