KR-102963079-B1 - Device and method for monitoring polymer using terahertz wave

KR102963079B1KR 102963079 B1KR102963079 B1KR 102963079B1KR-102963079-B1

Abstract

A polymer monitoring device using terahertz waves is provided. The polymer monitoring device using terahertz waves may include: an emitter that generates terahertz waves toward a polymer thin film coated on a target substrate; a detector that detects terahertz waves generated from the emitter and reflected from the surface of the target substrate or terahertz waves transmitted through the polymer thin film and the target substrate; and a monitoring unit that obtains information on the thickness and refractive index of the polymer thin film in real time through the terahertz waves detected by the detector while the polymer thin film is curing.

Inventors

김학성
김상일

Assignees

한양대학교 산학협력단

Dates

Publication Date: 20260511
Application Date: 20231214
Priority Date: 20230904

Claims (14)

An emitter that generates terahertz waves toward a polymer thin film coated on a target substrate; A detector for detecting terahertz waves generated from the emitter and reflected from the surface of the target substrate or terahertz waves transmitted through the polymer thin film and the target substrate; and A monitoring unit that acquires information on the thickness and refractive index of the polymer thin film in real time through terahertz waves detected by the detector while the polymer thin film is curing; The monitoring unit numerically calculates in real time the refractive index and thickness of the polymer thin film that change at each curing stage of the polymer thin film, by considering the ratio of the frequency domain value of the terahertz wave on the target substrate and the frequency domain value of the terahertz wave on the reference substrate. A polymer monitoring device using terahertz waves, wherein the reference substrate is defined as a substrate not coated with the polymer thin film.
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In Article 1, Refractive index of the above polymer thin film ( ) is calculated through Formula 1 below, and A polymer monitoring device using terahertz waves, wherein the thickness (d p ) of the above polymer thin film is calculated through the following Equation 2. [Formula 1] [Equation 2] Here, E t (t) is a terahertz wave reflected from the surface of the target substrate coated with the polymer thin film, E r (t) is a terahertz wave reflected from the surface of the reference substrate, ω is the frequency of the terahertz wave, φ is the phase difference between the terahertz wave reflected from the surface of the target substrate coated with the polymer thin film and the terahertz wave reflected from the surface of the reference substrate, c is the speed of light, θ1 is the angle of entry of the terahertz wave, θ2 is the angle of refraction of the terahertz wave, T ap and T pa are transmittance coefficients between air (a) and the polymer thin film, D a is the absorption coefficient of air, D p is the absorption coefficient of the polymer thin film, R ps is the reflection coefficient between the target substrate and the polymer thin film, R as is the reflection coefficient between the reference substrate and air, d a is the thickness of the air layer set to correspond to the polymer thin film, and is the refractive index of the above air layer.
In Article 1, The detector further detects terahertz waves reflected from within the target substrate, and The above monitoring unit is a polymer monitoring device using terahertz waves, capable of acquiring information on the thickness and refractive index of the polymer thin film in real time even through terahertz waves reflected from within the target substrate.
In Article 1, The above emitter and detector are a polymer monitoring device using terahertz waves that scans the entire area of the polymer thin film.
In Article 1, Include more databases, but, The above database stores reference ranges for refractive index and thickness for each stage of curing of the polymer thin film, and The above monitoring unit is a polymer monitoring device using terahertz waves that monitors whether the thickness and refractive index information of the polymer thin film acquired in real time falls within the reference range.
In Article 6, A polymer monitoring device using terahertz waves, wherein the monitoring unit provides the monitoring result as cause analysis data for anomaly occurrence when the thickness and refractive index information of the polymer thin film is not included in the reference range.
In Article 1, A polymer monitoring device using terahertz waves, wherein at least one emitter and a detector are provided, and provided in a corresponding number.
In Article 1, A polymer monitoring device using terahertz waves, wherein the emitter and detector are configured to operate in any one of a measurement mode, a transmission mode, a normal mode, a reflection mode, and a multimode combining the transmission mode and the reflection mode, based on the optical path of the terahertz waves for the polymer thin film.
In Article 1, A polymer monitoring device using terahertz waves, wherein the above terahertz waves are provided as a pulsed type or a continuous wave.
In Article 1, A polymer monitoring device using terahertz waves, wherein the frequency of the terahertz waves is 0.1 THz to 10 THz.
A step of generating terahertz waves toward a polymer thin film coated on a target substrate; A step of detecting terahertz waves reflected from the surface of the target substrate or terahertz waves transmitted through the polymer thin film and the target substrate; and The method includes the step of obtaining information on the thickness and refractive index of the polymer thin film in real time through the terahertz waves detected in the step of detecting the terahertz waves while the polymer thin film is curing; In the step of generating the above terahertz waves, terahertz waves are further generated toward a reference substrate that is not coated with the polymer thin film, and In the step of detecting the terahertz waves, the reference terahertz waves on the reference substrate are further detected, and A polymer monitoring method using terahertz waves, wherein in the step of acquiring in real time, the refractive index and thickness of the polymer thin film that change according to the curing step of the polymer thin film are numerically calculated in real time by considering the ratio of the frequency domain value of the terahertz wave at the target substrate and the frequency domain value of the terahertz wave at the reference substrate.
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In Article 12, A polymer monitoring method using terahertz waves, wherein the entire surface area of the polymer thin film is scanned in the step of generating the terahertz waves and the step of detecting the terahertz waves.

Description

Device and method for monitoring polymer using terahertz wave The present invention relates to a polymer monitoring device and method using terahertz waves, and more specifically, to a polymer monitoring device and method using terahertz waves capable of monitoring the curing state of a polymer thin film coated on a substrate in real time. Polymers are materials used in various industrial fields. For example, polymers applied in the semiconductor field are coated onto a substrate through spin coating or the like, and then undergo a curing process to form a functional layer. However, conventionally, it was not possible to measure or verify the curing state of the polymer in real time during the polymer coating process. In other words, conventionally, the state of the polymer could only be checked after the polymer had completely cured. Consequently, even if an abnormality occurred in the material or equipment during the process of forming the polymer layer, immediate action could not be taken, which led to frequent product defects. In addition, conventionally, there was a problem of delaying the process completion time because the curing state of the polymer was checked after the polymer was completely cured, and there was a risk of damage to the formed polymer layer because the curing state of the polymer was checked through physical means. In particular, as wafer area increases and linewidths become finer, the yield of photoresist (PR) has a significant impact on product yield; therefore, active measures are required to improve the yield during the photoresist (PR) curing process. FIG. 1 is a schematic diagram illustrating a polymer monitoring device according to one embodiment of the present invention. FIG. 2 is a schematic diagram showing a polymer monitoring device according to one embodiment of the present invention. FIG. 3 is a schematic diagram illustrating a polymer monitoring device according to one variant of the present invention. FIG. 4 is a schematic diagram illustrating a polymer monitoring device according to another variation of the present invention. FIG. 5 is a schematic diagram illustrating a polymer monitoring device according to another variant of the present invention. FIGS. 6 to 9 are exemplary drawings for explaining the monitoring unit of a polymer monitoring device according to one embodiment of the present invention. FIGS. 10 and 11 are results of monitoring the curing state of a photoresist while the photoresist coated on a silicon wafer is curing through a polymer monitoring device according to one embodiment of the present invention. FIG. 12 is a schematic diagram illustrating a photolithography process monitored in real time by a polymer monitoring device according to one embodiment of the present invention. FIG. 13 is a flowchart showing a polymer monitoring method using terahertz waves according to one embodiment of the present invention in process order. Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the attached drawings. However, the technical concept of the present invention is not limited to the embodiments described herein and may be embodied in other forms. Rather, the embodiments introduced herein are provided to ensure that the disclosed content is thorough and complete and to ensure that the concept of the present invention is sufficiently conveyed to those skilled in the art. In this specification, when a component is described as being on another component, it means that it may be formed directly on the other component or that a third component may be interposed between them. Additionally, in the drawings, shapes and sizes are exaggerated for the effective illustration of the technical content. Additionally, although terms such as first, second, third, etc., have been used to describe various components in the various embodiments of this specification, these components should not be limited by such terms. These terms are used merely to distinguish one component from another. Accordingly, what is referred to as the first component in one embodiment may be referred to as the second component in another embodiment. Each embodiment described and illustrated herein also includes its complementary embodiment. Furthermore, in this specification, "and/or" is used to mean including at least one of the components listed before and after it. In the specification, singular expressions include plural expressions unless the context clearly indicates otherwise. Furthermore, terms such as "include" or "have" are intended to specify the existence of the features, numbers, steps, components, or combinations thereof described in the specification, and should not be understood as excluding the existence or addition of one or more other features, numbers, steps, components, or combinations thereof. Additionally, in this specification, "connection" is used to include both indirectly connecting multiple components and directly