WO2010016636A1

WO2010016636A1 - Spectrometer

Info

Publication number: WO2010016636A1
Application number: PCT/KR2008/005267
Authority: WO
Inventors: Soon-Jong Lee; Bong-Joo Woo
Original assignee: Semisysco Co., Ltd.
Priority date: 2008-08-07
Filing date: 2008-09-05
Publication date: 2010-02-11
Also published as: TWI377337B; KR20100018742A; TW201007142A

Abstract

Provided is a spectrometer. The spectrometer is configured such that a detector and a PCB as components in the spectrometer can be angularly adjusted and reciprocated to and fro, and an optical fiber is branched off into several wires and disposed at a front transparent window of an optical port of an inspection object. As a result, it is possible to widely collect the entire spectrum of optical emission generated in a specific space. Therefore, it is possible to examine chemical elements of an unknown material and more precisely detect specifications of structures, operations, or environmental characteristics (an inner temperature, a pressure, a magnetic magnitude, and so on) of a known material or an object.

Description

Description SPECTROMETER

Technical Field

[1] The present invention relates to a spectrometer, and more particularly, to a spectrometer capable of expanding a light collecting range of optical emission from an inspection object (for example, a chamber in chemical vapor deposition (CVD), high density plasma chemical vapor deposition (HDP CVD), and an etcher) requiring detecting optical emission. Background Art

[2] Generally, a spectrometer is widely used in material analysis applications to measure dispersion of specific color light due to selective absorption and radiation problems.

[3] That is, the spectrometer measures a specific wavelength of optical emission using an amount of radiation from an unknown sample when light is appropriately energized by an absorption or reflection amount by the sample. An important purpose of spectrum measurement is to examine chemical elements of an unknown material or specifically explain structure, operation, or environmental characteristics (internal temperature, pressure, magnetic magnitude, and so on) of known materials or target materials.

[4] For example, the spectrometer is used to monitor a plasma process using optical emission spectroscopy, i.e., to monitor the plasma process by measuring optical emission from plasma discharge.

[5] That is, a gas existing in plasma generations optical emission by characteristics of atoms and molecules, and the optical emission is collected to monitor the plasma process through spectral analysis.

[6] At this time, in order to collect the optical emission of plasma in a process chamber as an inspection object using the optical emission spectroscopy as described above, an optical fiber and a spectrometer are generally provided.

[7] That is, as shown in FIG. 1, when a collimating lens is mounted on a front transparent window, which is an optical point of an inspection object (for example, a process chamber) 200, one end of an optical fiber 100 is positioned at the collimating lens, and the other end of the optical fiber 100 is connected to a spectrometer 300 disposed at the exterior of the inspection object 200.

[8] Therefore, when the optical fiber 100 collects optical emission of plasma, the spectrometer 300 analyzes spectrum of the collected optical emission and then converts the spectrum into an electric signal.

[9] Next, spectrum analysis information of the optical emission converted into the electric signal by the spectrometer 100 is transmitted to a processor (not shown) such that the processor finally analyzes the optical emission.

[10] As shown in FIG. 2, the spectrometer 300 includes an inlet slit 1, a collimating mirror 2, a grating part 3, a focusing mirror 4, a detector (a charge coupled device (CCD) lens 5), and a printed circuit board (PCB) 6 on which a signal converter (not shown) is mounted.

[11] That is, when the optical emission of the plasma enters through the inlet slit 1 connected to one end of the optical fiber 100, the entered optical emission is reflected by the collimating mirror 2 to the grating part 3, and the grating part 3, which acts as an optical distributor, distributes the spectrum of the optical emission to transmit it to the focusing mirror 4.

[12] Then, the focusing mirror 4 focuses the spectrum of the distributed optical emission and then transmits it to the detector 5. The detector 5 collects the spectrum of the focused optical emission, and the spectrum of the collected optical emission is converted into an electrical signal by the signal converter mounted on the PCB 6 to be transmitted to the processor. Then, the processor detects leak generation in the inspection object 200.

[13] At this time, the focusing mirror 4 is reciprocal to and fro, and therefore, the detector

5 can detect spectra 1 and 2 of specific wavelength regions as shown in FIG. 2 from reciprocal movement of the focusing mirror 4.

[14] For example, as shown in FIG. 1, when external air is injected into the inspection object 200 to cause a leak phenomenon in which spectrum of nitrogen (N₂), oxygen (O₂ ), argon (Ar), or the like, among the plasma spectrum, is generated, the spectrum, which causes the leak phenomenon, is spectroscoped through the spectrometer 300, and thus, the processor can detect leak generation through the spectroscoped spectrum.

[15] However, since the conventional spectrometer 300 includes the detector 5, which is stationary as an inner component, and the focusing mirror 4, which is reciprocal to and fro, when the focusing mirror 4 is reciprocated to adjust a distance from the detector 5, it is impossible to fine a flat field condition in which all spectra 1 and 2 of specific wavelength regions are focused. Therefore, the spectrum of the optical emission by the detector 5 is limited to a specific region, other than widely distributed.

[16] That is, the detector 5 uses a charge coupled device (CCD), but cannot accommodate all spectra of the optical emission focused by the focusing mirror 4, which is reciprocal to and fro. Therefore, the processor cannot precisely analyze all the spectrum of the optical emission focused by the focusing mirror 4 due to aberration, and can analyze only the spectrum of the specific region. As a result, it is likely to cause errors in applications such as leak detection by spectrum analysis.

[17] In addition, in the conventional spectrometer 300, the detector 5 is coupled to the

PCB 6, on which the signal converter is mounted, by soldering A shown in FIG. 2 to maintain a predetermined inclination angle of the detector 5. However, there is a fine difference of the inclination angle due to coupling of the soldering part A to the detector 5 such that the detector 5 cannot appropriately collect the spectrum of the optical emission focused by the focusing mirror 4.

[18] Further, while the collimating lens is mounted on the front transparent window of a plurality of optical ports disposed around the inspection object 200, one end of the optical fiber 100 is connected to the collimating lens, and the other end of the optical fiber 100 is connected to the spectrometer 300, since an observation angle is determined depending on a numerical aperture (NA) of the collimating lens, when the optical emission generated from the inspection object 200 is collected through the optical fiber 100, the optical emission should be collected in an extremely limited manner.

Disclosure of Invention Technical Problem

[19] In order to solve the foregoing and/or other problems, it is an aspect of the present invention to provide a spectrometer configured such that a detector and a PCB as components in the spectrometer can be angularly adjusted and reciprocated to and fro. As a result, it is possible to vary a position of spectrum of optical emission focused by a focusing mirror to collect the entire spectrum. Therefore, even though a separate apparatus is not further provided, it is possible to examine chemical elements of an unknown material and more precisely detect specifications of structures, operations, or environmental characteristics (an inner temperature, a pressure, a magnetic magnitude, and so on) of a known material or an object.

[20] It is another aspect of the present invention to provide a spectrometer having a structure, in which one end of an optical fiber is connected to the spectrometer, and the other end of the optical fiber is branched off into several wires, to expand a collection range of optical emission in a specific space. Technical Solution

[21] The foregoing and/or other aspects of the present invention may be achieved by providing a spectrometer including: an inlet slit for guiding introduction of optical emission when the optical emission is collected from an optical fiber disposed at a front transparent window of an optical port disposed at an inspection object; a collimating mirror for arranging and reflecting the optical emission entering through the inlet slit; a grating part for distributing the spectrum of the optical emission reflected by the collimating mirror; a focusing mirror for focusing the spectrum of the optical emission distributed by the grating part; and a condensing part for condensing the spectrum of the optical emission focused through the focusing mirror and converting the condensed spectrum into an electrical signal, wherein the condensing part performs reciprocal movement and inclination adjustment using a drive part such that several optical emission spectra focused through the focusing mirror are condensed in various angles.

[22] In addition, the condensing part may include a detector, and a printed circuit board

(PCB), on which a signal converter is mounted, and the detector and the PCB are parallelly coupled to each other.

[23] Further, the detector and the PCB, which are coupled to each other, may be coupled to an angle adjustment base.

[24] Furthermore, the angle adjustment base may be coupled to a reciprocal movement base.

[25] In addition, the drive part may include a first drive part driven to adjust an inclination angle of the angle adjustment base to which the condensing lens is attached, and a second drive part simultaneously reciprocating the angle adjustment base and the condensing part attached thereto.

[26] Further, the first drive part may include a first motor driven in forward and backward directions; and a rotary shaft part having a rotary gear part meshed with a drive gear of the first motor and passing through the angle adjustment base to adjust the inclination angle of the angle adjustment base when the first motor is driven in forward and backward directions.

[27] Furthermore, the second drive part may include a rack gear part disposed at one end of the reciprocal movement base; a drive shaft gear part meshed with the rack gear part; and a second motor for rotating the drive shaft gear part to reciprocate the reciprocal movement base having the rack gear part in forward and backward directions.

[28] In addition, the second drive part may be constituted by a pneumatic or hydraulic cylinder, and a piston rod of the cylinder may be connected to the reciprocal movement base to reciprocate the reciprocal movement base.

[29] Further, the optical fiber may be branched off into several wires and disposed at a front transparent window of an optical port of an inspection object.

Advantageous Effects

[30] According to the present invention, a spectrometer is configured such that a detector and a PCB as components in the spectrometer can be angularly adjusted and reciprocated to and fro, and an optical fiber is branched off into several wires and disposed at a front transparent window of an optical port of an inspection object. As a result, it is possible to vary a position of spectrum of optical emission focused by a focusing mirror to collect the entire spectrum. Therefore, it is possible to examine chemical elements of an unknown material and more precisely detect specifications of structures, operations, or environmental characteristics (an inner temperature, a pressure, a magnetic magnitude, and so on) of a known material or an object. Brief Description of the Drawings

[31] The above and other aspects and advantages of the present invention will become apparent and more readily appreciated from the following description of exemplary embodiments, taken in conjunction with the accompanying drawings of which:

[32] FIG. 1 is a perspective view of a conventional spectrometer;

[33] FIG. 2 is a schematic view of a condensed state of the conventional spectrometer;

[34] FIG. 3 is a schematic view of a spectrometer in accordance with an exemplary embodiment of the present invention;

[35] FIG. 4 is a view showing an inclination angle adjustment state of a condensing part in accordance with an exemplary embodiment of the present invention;

[36] FIG. 5 is a view showing a reciprocal movement state of the condensing part in accordance with an exemplary embodiment of the present invention;

[37] FIG. 6 is a view showing a mounting state of an optical finer in accordance with an exemplary embodiment of the present invention; and

[38] FIG. 7 is a view of a second drive part for reciprocal movement in accordance with another exemplary embodiment of the present invention.

[39] * Description of Major Reference Numerals *

[40] 11 : Inlet slit 12: Collimating mirror

[41] 13: Grating part 14: Focusing mirror

[42] 15: Condensing part 15a: Detector

[43] 15b: PCB 20: Angle adjustment base

[44] 30: Reciprocal movement base 40: First drive part

[45] 41 : First motor 42: Drive gear

[46] 43: Rotary gear part 44: Rotary shaft part

[47] 50: Second drive part 51 : Rack gear part

[48] 52: Drive shaft gear part 53: Second motor

[49] 61 : Cylinder 62: Piston rod

[50] 100: Optical fiber 200: Process chamber

[51] 300: Spectrometer

Mode for the Invention

[52] Reference will now be made in detail to the embodiments of the present invention, examples of which are illustrated in the accompanying drawings.

[53] FIG. 3 is a schematic view of a spectrometer in accordance with an exemplary embodiment of the present invention, FIG. 4 is a view showing an inclination angle adjustment state of a condensing part in accordance with an exemplary embodiment of the present invention, FIG. 5 is a view showing a reciprocal movement state of the condensing part in accordance with an exemplary embodiment of the present invention, and FIG. 6 is a view showing a mounting state of an optical finer in accordance with an exemplary embodiment of the present invention.

[54] Referring to FIGS. 3 to 6, in accordance with an exemplary embodiment of the present invention, a collimating lens is mounted on a front transparent window of an optical port of an inspection object (for example, a process chamber) 200, one end of an optical fiber 100 is disposed at the collimating lens, and the other end of the optical fiber 100 is connected to a spectrometer 300. In this state, the spectrometer 300 condenses the entire spectrum of optical emission of the inspection object 200 to increase analysis precision using a process. The optical fiber 100 is branched off into several wires Al, A2 and A3 connected to the collimating lens mounted on the front transparent window of the optical port of the inspection object 200. Therefore, the optical fiber 100 is configured to more widely collect optical emission generated from the inspection object 200.

[55] The spectrometer 300 includes an inlet slit 11, a collimating mirror 12, a grating part

13, a focusing mirror 14, a condensing part 15, a drive part, an angle adjustment base 20, and a reciprocal movement base 30.

[56] The inlet slit 11 functions to guide introduction of optical emission when the optical fiber 100 disposed at the front transparent window of the optical port of the inspection object 200 collects the optical emission.

[57] The collimating mirror 12 is configured to align the optical emission entering through the inlet slit 11 and then to reflect the optical emission by the grating part 13.

[58] The grating part 13, which is an optical distribution element, is configured to distribute the spectrum of the optical emission reflected through the collimating mirror 12.

[59] The focusing mirror 14 is configured to focus the spectrum of the optical emission distributed by the grating part 13.

[60] The condensing part 15 condenses the spectrum of the optical emission focused through the focusing mirror 14, and then, converts the spectrum into an electrical signal. The condensing part 15 includes a detector 15a formed of a CCD lens, and a PCB 15b on which a signal converter is mounted, which are parallelly coupled to each other to prevent generation of a fine difference of an installation angle depending on coupling thereof.

[61] At this time, the condensing part 15 including the detector 15a and the PCB 15b, which are parallel to each other, is fixedly installed at the angle adjustment base 20. The angle adjustment base 20 is installed at the reciprocal movement base 30 to be angularly adjusted. [62] The drive part is configured to adjust an inclination angle of the condensing part 15 or reciprocates it such that the condensing part 15 including the detector 15a and the PCB 15b can condense the entire spectra of the optical emission focused through the focusing mirror 14. The drive part includes first and second drive parts 40 and 50, which are driven by a controller (not shown) or a pre-set manual.

[63] Here, the controller may be a computer mounted on the PCB or disposed outside the spectrometer, which may be controlled by a processor.

[64] The first drive part 40 is configured to adjust an inclination angle of the condensing part 15 including the detector 15a and the PCB 15b, parallelly and integrally coupled to each other, through inclination angle adjustment of the angle adjustment base 20. The first drive part 40 includes a first motor 41, a drive gear 42, a rotary gear part 43, and a rotary shaft part 44.

[65] That is, the first drive part 40 includes the first motor 41 driven in forward and backward directions, the rotary gear part 43 meshed with the drive gear 42 of the first motor 41, and the rotary shaft part 44 passing through the angle adjustment base 20 to adjust an inclination angle of the angle adjustment base 20, at which the condensing part 15 is installed, when the first motor 41 is driven in forward and backward directions, wherein the rotary gear part 43 is integrally formed with the rotary shaft part 44.

[66] The second drive part 50 is configured to simultaneously reciprocate the angle adjustment base 20 and the condensing part 15 coupled thereto. The second drive part 50 includes a rack gear part 51, a drive shaft gear part 52, and a second motor 53.

[67] That is, the second drive part 50 is configured such that, when the drive shaft gear part 52 is driven depending on forward and backward driving of the second motor 53, the rack gear part 52 integrally formed with one end of the reciprocal movement base 30 is meshed with the drive shaft gear part 52 to reciprocate, and thus, the reciprocal movement base 30 integrally formed with the rack gear part 51 reciprocates.

[68] Operations of the exemplary embodiment in accordance with the present invention will be described with reference to FIGS. 3 to 6.

[69] First, when a process gas is injected into an inspection object 200 such as a process chamber of CVD equipment (or etch equipment) and then an RF power is applied, the process gas injected into the inspection object 200 is activated into a plasma state by high frequency generated from an RF generating apparatus (not shown) to deposit a thin film on a substrate.

[70] At this time, during a process of depositing the thin film, optical emission is generated from the inspection object 200.

[71] The optical emission is collected by an optical fiber 100 formed of a single wire or several wires Al, A2 and A3 disposed at a collimating lens mounted on a front transparent window of an optical port of the inspection object 200 and then transmitted to the spectrometer 300.

[72] Then, the optical emission is guided by an inlet slit 11 formed at the spectrometer

300 to enter a collimating mirror 12, and the collimating mirror 12 aligns the plasma optical emission to reflect it to a grating part 13 as an optical distribution element.

[73] Therefore, the grating part 13 distributes the spectrum of the optical emission reflected through the collimating mirror 12, and the spectrum of the optical emission distributed by the grating part 13 is focused by a focusing mirror 14.

[74] At this time, only the spectrum of the optical emission corresponding to a specific region among the spectrum of the optical emission focused by the focusing mirror 14 is condensed through a detector 15a as a CCD lens included in the condensing part 15, and the spectrum of the condensed optical emission is converted into an electrical signal through a signal converter mounted on the PCB 15b to be transmitted to a processor.

[75] Therefore, the processor can analyze whether spectrum of nitrogen (N₂), oxygen (O₂), argon (Ar), or the like, is included in the optical emission, and determine whether a leak is generated from the inspection object 200 through the analysis.

[76] Meanwhile, it may not be accurately determined whether the leak is generated using the spectrum of the specific optical emission condensed by the condensing part 15. In this case, inclination angle adjustment or reciprocal movement of the condensing part 15 enables to condense of the spectrum of the entire optical emission focused by the focusing mirror 14 to precisely detect generation of the leak.

[77] First, referring the inclination angle adjustment of the condensing part 15 with reference to FIG. 4, when the first motor 41 is rotated in a forward or backward direction under the control of the controller, the drive gear 42 coupled to the first motor 41 is rotated.

[78] At this time, the rotary gear part 43 is meshed with the drive gear 42, and the rotary gear part 43 is coupled to one end of the rotary shaft part 44 passing through the angle adjustment base 20.

[79] Therefore, the rotary shaft part 44 can be rotated through engagement between the drive gear 42 and the rotary gear part 43, and the angle adjustment base 20 coupled to the rotary shaft part 44 can be angularly adjusted forward or backward.

[80] As a result, the detector 15a of the condensing part 15 installed at the angle adjustment base 20 detects variation in inclination angle of the spectrum of the optical emission, and condenses the spectrum of another optical emission focused by the focusing mirror 14.

[81] In addition, as shown in FIG. 6, in the case of reciprocal movement of the condensing part 15, when the second motor 53 is rotated in a forward or backward direction under the control of the controller, the drive shaft gear part 52 connected to the second motor 53 is rotated.

[82] At this time, the drive shaft gear part 52 is meshed with the rack gear part 51 integrally formed with one end of the reciprocal movement base 30, and the condensing part 15 and the angle adjustment base 20 are installed at the reciprocal movement base 30.

[83] The drive shaft gear part 52 is meshed with the rack gear part 51 to move the reciprocal movement base 30 in a forward or backward direction.

[84] Therefore, the detector 15a of the condensing part 15 installed at the angle adjustment base 20 detects variation in inclination angle of the spectrum of the optical emission, and thus, the detector 15a can condense the spectrum of the more expanded optical emission.

[85] As a result, when the detector 15a condenses the spectrum of the entire optical emission focused by the focusing mirror 14 through variation in inclination angle of the detector 15a, the spectrum of the condensed optical emission is converted into an electrical signal through a signal converter mounted on the PCB 15b and then transmitted to the processor.

[86] Therefore, the processor can more widely analyze the entire spectrum of the optical emission generated from the inspection object 200, and thus, more precisely detect generation of the leak from the inspection object 200.

[87] That is, the condensing part 15 can reciprocate and adjust an inclination angle thereof to condense the spectrum of the entire optical emission in a field-field-condition focused by the focusing mirror 14.

[88] Meanwhile, FIG. 7 shows another embodiment in accordance with the present invention to reciprocate a reciprocal movement base 30 using a cylinder. For this purpose, a pneumatic or hydraulic cylinder 61 is provided, and a piston rod 62 of the pneumatic or hydraulic cylinder 61 is connected to the reciprocal movement base 30 to receive a pneumatic or hydraulic pressure by a supply apparatus (not shown) operated under the control of the controller.

[89] In addition, as shown in FIG. 6, when the collimating lens is mounted on the front transparent window of the optical port of the inspection object 200, one ends Al, A2 and A3 of the optical fiber 100 branched off into several wires are disposed at the collimating lens. As a result, it is possible to overcome physical limitation of an observation angle determined by a numerical aperture (NA) of the collimating lens and expand a collection range of the optical emission generated from the inspection object 200 by the optical fiber 100. Therefore, the spectrometer 300 also can expand a condensing range of the spectrum of the optical emission.

[90] The foregoing description concerns an exemplary embodiment of the invention, is intended to be illustrative, and should not be construed as limiting the invention. Many alternatives, modifications, and variations within the scope and spirit of the present invention will be apparent to those skilled in the art.

Claims

[ 1 ] A spectrometer comprising : an inlet slit for guiding introduction of optical emission when the optical emission is collected from an optical fiber disposed at a front transparent window of an optical port disposed at an inspection object; a collimating mirror for arranging and reflecting the optical emission entering through the inlet slit; a grating part for distributing the spectrum of the optical emission reflected by the collimating mirror; a focusing mirror for focusing the spectrum of the optical emission distributed by the grating part; and a condensing part for condensing the spectrum of the optical emission focused through the focusing mirror and converting the condensed spectrum into an electrical signal, wherein the condensing part performs reciprocal movement and inclination adjustment using a drive part such that several optical emission spectra focused through the focusing mirror are condensed in various angles.

[2] The spectrometer according to claim 1, wherein the condensing part comprises a detector, and a printed circuit board (PCB), on which a signal converter is mounted, and the detector and the PCB are parallelly coupled to each other.

[3] The spectrometer according to claim 2, wherein the detector and the PCB, which are coupled to each other, are coupled to an angle adjustment base.

[4] The spectrometer according to claim 3, wherein the angle adjustment base is coupled to a reciprocal movement base.

[5] The spectrometer according to claim 1, wherein the drive part comprises: a first drive part driven to adjust an inclination angle of the angle adjustment base to which the condensing lens is attached; and a second drive part simultaneously reciprocating the angle adjustment base and the condensing part attached thereto.

[6] The spectrometer according to claim 5, wherein the first drive part comprises: a first motor driven in forward and backward directions; and a rotary shaft part having a rotary gear part meshed with a drive gear of the first motor and passing through the angle adjustment base to adjust the inclination angle of the angle adjustment base when the first motor is driven in forward and backward directions.

[7] The spectrometer according to claim 5, wherein the second drive part comprises: a rack gear part disposed at one end of the reciprocal movement base; a drive shaft gear part meshed with the rack gear part; and a second motor for rotating the drive shaft gear part to reciprocate the reciprocal movement base having the rack gear part in forward and backward directions.

[8] The spectrometer according to claim 5, wherein the second drive part is constituted by a pneumatic or hydraulic cylinder, and a piston rod of the cylinder is connected to the reciprocal movement base to reciprocate the reciprocal movement base.

[9] The spectrometer according to claim 1, wherein the optical fiber is branched off into several wires and disposed at a front transparent window of an optical port of an inspection object.

[10] A spectrometer comprising : an inlet slit for guiding introduction of optical emission when the optical emission is collected from an optical fiber disposed at a front transparent window of an optical port disposed at an inspection object; a collimating mirror for arranging and reflecting the optical emission entering through the inlet slit; a grating part for distributing the spectrum of the optical emission reflected by the collimating mirror; a focusing mirror for focusing the spectrum of the optical emission distributed by the grating part; and a condensing part for condensing the spectrum of the optical emission focused through the focusing mirror and converting the condensed spectrum into an electrical signal, wherein a collimating lens having an observation angle determined depending on a numerical aperture is mounted on the front transparent window of the optical port, and one end of the optical fiber is disposed at the collimating lens, and the optical fiber is branched off into several wires and disposed at the collimating lens.