JPH06167444A - Evaluating apparatus for photoresist - Google Patents

Abstract

PURPOSE:To enable efficient measurement of a photoresist for a plurality of wavelengths in a measuring unit which applies light to the photoresist and determines the light-absorption characteristic and sensitivity of the photoresist on the basis of a change in transmittance. CONSTITUTION:In order to save the waste that a measuring unit equipped with light sources and optical systems corresponding to discrete wavelengths needs to be used when a plurality of photoresists are measured, an apparatus is so designed that it can evaluate and measure a photoresist 6 for several kinds of wavelengths by one optical system including a light source 1. An optical lens 2 is fitted so that light of a short wavelength of the light source 1 of which the radiation strength is the smallest be made to have the largest strength on the surface of the photoresist 6. A component of the optical system such as a filter 4 is adjusted to lower strength of the light for each wavelength so that the same strength as the strength of that light be obtained.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to semiconductor device manufacturing, and more particularly to a photoresist evaluation apparatus.

[0002]

2. Description of the Related Art Photoresists consist of resin and photosensitizer. The photosensitizer absorbs light when exposed to light, and the photosensitizing group undergoes a chemical change. Therefore, the light transmittance changes. Since the degree of this change varies depending on the type of photoresist, it is possible to evaluate the characteristics of the photoresist.

In recent years, IBM's Dill et al. Further quantified this, and based on a change curve of photoresist exposure time and light transmittance, the degree of light absorption of a photosensitizer, the degree of light absorption of a resin, and decomposition of the photosensitizer. A method to evaluate the characteristics of photoresist by obtaining speed was announced. Since then, the evaluation of photoresists by this method has become widespread.

F. H. Dill et al. , IE
EE Trans. Electron Devices,
vol. ED-22, No, 7, p. 445,197
5.

[0005]

The wavelength of the light source for exposing the photoresist currently used is 365 nm.
, 436 nm is common, and recently, a wavelength of 248 nm is also beginning to be used. However, since the light emitted from one light source has different radiation intensity depending on the wavelength, it is necessary to change the light source and the optical system depending on the wavelength used in order to obtain sufficient light intensity.

[0006]

SUMMARY OF THE INVENTION The present invention eliminates the waste of having to use a measuring instrument equipped with a light source and an optical system corresponding to each wavelength when measuring a plurality of photoresists. The purpose is to be able to evaluate and measure photoresists for several wavelengths with a light source and an optical system.

The optical lens is installed so that the light of the wavelength having the weakest emission intensity of the light source has the highest intensity on the photoresist surface. Further, an optical system such as a filter is adjusted so as to reduce the intensity of light at each wavelength so that the intensity becomes the same.

[0008]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a diagram showing an example of a measuring device. In the figure, 1 is a light source. As the light source, for example, a xenon lamp, a high pressure mercury lamp, a flash lamp or the like can be used. Reference numeral 2 denotes a lens, which is, for example, synthetic quartz, fused quartz, or sapphire. 3 is a shutter, 4 is a bandpass filter, for example, a metal interference filter. An optical sensor 5 is, for example, a silicon diode or a photoelectric tube. 6 is a photoresist,
A substrate 7 is, for example, synthetic quartz, fused silica, or sapphire. An antireflection film, for example, a MgF thin film may be provided on the surface. 8 is a mirror. Reference numeral 9 denotes a filter holder to which several types of filters are attached according to the type of wavelength to be measured.

In this apparatus, light from a light source is collected by a lens on a photoresist surface through a filter and a mirror. Then, the light-sensitive group of the photoresist is transmitted while being chemically changed, further passes through the substrate, and then enters the sensor. A sensor measures the temporal change of the transmitted light. The lens is adjusted and fixed so that the light from the light source transmitted through the filter is the weakest among the several filters so that the light is collected on the photoresist surface. In other filters, the transmittance of the filter is adjusted so that the light intensity becomes the same or the exposure time until the transmittance saturates becomes the same as much as possible. At this time, for example, a diffusion plate may be used.

With the above-mentioned device configuration, the object of the present invention can be achieved. That is, a high-pressure mercury lamp of 150 W (Hamamatsu Photonics, model number L2482) was used as a light source, and as a result of appropriately adjusting the lens system and the diffusion plate, 436 nm, 36
Light intensity at 5 nm and 248 nm is 4.4 m, respectively
W / cm ² , 4.5 mW / cm ² , and 4.5 mW / cm ² were obtained, and the light intensity of 248 nm, which is usually the weakest, was about the same as the others. The exposure time to reach saturation is 3 each
Minutes, 4 minutes, 4 minutes. Further, since the light of the wavelength which has been weak in the past becomes strong enough, the signal-to-noise ratio is remarkably improved and the measured value can be obtained with high accuracy.

[0012]

As described in detail above, according to the method of the present invention, a photoresist can be evaluated and measured efficiently and highly accurately for several wavelengths with one light source and optical system.

[Brief description of drawings]

FIG. 1 is an explanatory view schematically showing an example of an apparatus according to the present invention.

[Explanation of symbols]

 1 Light Source 2 Lens 3 Shutter 4 Filter 5 Sensor 6 Photoresist 7 Substrate 8 Mirror 9 Filter Holder

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁵ Identification number Internal reference number FI Technical indication H01L 21/66 L 7377-4M (72) Inventor Hisayuki Miyagawa Kawasaki-cho, Shibata-gun, Miyagi Prefecture Kitakawa, Kawauchi Harayama 228 Tohoku Nakayauchi Co., Ltd. (72) Inventor Koji Honma 2-703, Tateno, Higashiyamato-shi, Tokyo Inside Chemitronics Co., Ltd. (72) Inventor Toshiharu Matsuzawa 1-345-16-101 Ogawamachi, Kodaira-shi, Tokyo Company techno front

Claims (1)

[Claims] 1. A measuring instrument for determining light absorption characteristics and sensitivity of a photoresist by irradiating the photoresist with light and changing the transmittance, wherein the intensity of light of a plurality of kinds of wavelengths is made substantially the same on the photoresist surface. And measuring instrument.