KR100481545B1 - Method for wafer alignment by using double wavelength laser - Google Patents
Method for wafer alignment by using double wavelength laser Download PDFInfo
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- KR100481545B1 KR100481545B1 KR10-2002-0037529A KR20020037529A KR100481545B1 KR 100481545 B1 KR100481545 B1 KR 100481545B1 KR 20020037529 A KR20020037529 A KR 20020037529A KR 100481545 B1 KR100481545 B1 KR 100481545B1
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- 230000009977 dual effect Effects 0.000 claims abstract description 18
- 238000005259 measurement Methods 0.000 claims abstract description 5
- 238000006243 chemical reaction Methods 0.000 claims description 2
- 235000012431 wafers Nutrition 0.000 claims 9
- 230000003287 optical effect Effects 0.000 claims 1
- 238000010586 diagram Methods 0.000 description 3
- 230000000694 effects Effects 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 238000000206 photolithography Methods 0.000 description 1
- 239000004065 semiconductor Substances 0.000 description 1
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- G—PHYSICS
- G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
- G03F—PHOTOMECHANICAL PRODUCTION OF TEXTURED OR PATTERNED SURFACES, e.g. FOR PRINTING, FOR PROCESSING OF SEMICONDUCTOR DEVICES; MATERIALS THEREFOR; ORIGINALS THEREFOR; APPARATUS SPECIALLY ADAPTED THEREFOR
- G03F9/00—Registration or positioning of originals, masks, frames, photographic sheets or textured or patterned surfaces, e.g. automatically
- G03F9/70—Registration or positioning of originals, masks, frames, photographic sheets or textured or patterned surfaces, e.g. automatically for microlithography
- G03F9/7088—Alignment mark detection, e.g. TTR, TTL, off-axis detection, array detector, video detection
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- G—PHYSICS
- G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
- G03F—PHOTOMECHANICAL PRODUCTION OF TEXTURED OR PATTERNED SURFACES, e.g. FOR PRINTING, FOR PROCESSING OF SEMICONDUCTOR DEVICES; MATERIALS THEREFOR; ORIGINALS THEREFOR; APPARATUS SPECIALLY ADAPTED THEREFOR
- G03F7/00—Photomechanical, e.g. photolithographic, production of textured or patterned surfaces, e.g. printing surfaces; Materials therefor, e.g. comprising photoresists; Apparatus specially adapted therefor
- G03F7/70—Microphotolithographic exposure; Apparatus therefor
- G03F7/70483—Information management; Active and passive control; Testing; Wafer monitoring, e.g. pattern monitoring
- G03F7/70605—Workpiece metrology
- G03F7/70616—Monitoring the printed patterns
- G03F7/70633—Overlay, i.e. relative alignment between patterns printed by separate exposures in different layers, or in the same layer in multiple exposures or stitching
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L21/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
- H01L21/67—Apparatus specially adapted for handling semiconductor or electric solid state devices during manufacture or treatment thereof; Apparatus specially adapted for handling wafers during manufacture or treatment of semiconductor or electric solid state devices or components ; Apparatus not specifically provided for elsewhere
- H01L21/68—Apparatus specially adapted for handling semiconductor or electric solid state devices during manufacture or treatment thereof; Apparatus specially adapted for handling wafers during manufacture or treatment of semiconductor or electric solid state devices or components ; Apparatus not specifically provided for elsewhere for positioning, orientation or alignment
- H01L21/681—Apparatus specially adapted for handling semiconductor or electric solid state devices during manufacture or treatment thereof; Apparatus specially adapted for handling wafers during manufacture or treatment of semiconductor or electric solid state devices or components ; Apparatus not specifically provided for elsewhere for positioning, orientation or alignment using optical controlling means
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- Condensed Matter Physics & Semiconductors (AREA)
- Manufacturing & Machinery (AREA)
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- Microelectronics & Electronic Packaging (AREA)
- Power Engineering (AREA)
- Multimedia (AREA)
- Exposure Of Semiconductors, Excluding Electron Or Ion Beam Exposure (AREA)
- Length Measuring Devices By Optical Means (AREA)
Abstract
본 발명은 이중 파장 레이저를 이용한 웨이퍼 정렬 방법에 관한 것으로, 얼라인먼트에 이용되는 이중 파장의 He-Ne 레이저(Layer) 광원을 입사하게 되면, 입사되는 광원에 따라 웨이퍼 상에 일정한 피치(pitch)의 웨이퍼 얼라인 마크가 형성되고, 입사된 광원이 반사되는 경우, 검출기는 웨이퍼 얼라인 마크에서 첫 번째 파장에 대응하는 ±1차 및 ±2차 회절된 빔과, 두 번째 파장에 대응하는 ±1차 및 ±2차 회절된 빔의 광량을 검출한다. 따라서, 첫 번째 및 두 번째 파장에 대응하는 ±1차 및 ±2차 회절빔의 광량을 동시에 검출하여 측정의 정밀도와 신뢰도를 향상시켜 정밀한 오버레이를 구현할 수 있는 효과가 있다. BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a wafer alignment method using a dual wavelength laser. When a dual wavelength He-Ne laser light source used for alignment is incident, a wafer having a constant pitch on the wafer according to the incident light source When an align mark is formed and the incident light source is reflected, the detector detects the first and second order diffracted beams corresponding to the first wavelength in the wafer align mark, the first order corresponding to the second wavelength and The amount of light in the ± 2nd order diffracted beam is detected. Therefore, the amount of light of the ± 1st and ± 2nd order diffraction beams corresponding to the first and second wavelengths can be detected at the same time, thereby improving the accuracy and reliability of the measurement, thereby implementing a precise overlay.
Description
본 발명은 이중 파장 레이저를 이용한 웨이퍼 정렬 방법에 관한 것으로, 특히 포토 공정(photo process) 과정에 있어서, 이중 파장 레이저를 입사시키고, 반사되는 2개의 파장에 대응하는 회절빔의 세기를 검출하여 오버레이(overlay)를 향상시킬 수 있는 정렬방법에 관한 것이다. BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a wafer alignment method using a dual wavelength laser. In particular, in a photo process, a dual wavelength laser is incident and an intensity of a diffraction beam corresponding to two reflected wavelengths is detected. It is about sorting method which can improve overlay.
통상적으로, 반도체 제조 공정 과정 중 마스크(mask)의 이미지(image)를 웨이퍼 상에 프린트하는 포토 공정 과정에서 매우 중요한 요소는 층간 중첩도(layer to layer overlay)이다.Typically, a critical factor in the photolithography process of printing an image of a mask on a wafer during a semiconductor fabrication process is layer to layer overlay.
이러한, 층간 중첩도는 정확한 오버레이(overlay)가 구현되어야 하며, 이 오버레이 구현은 정밀한 웨이퍼 얼라인먼트(Alignment)가 선행되어야 한다.Such layer overlap should be implemented with precise overlay, which must be preceded by precise wafer alignment.
도 1에 도시된 웨이퍼 얼라인먼트 장치의 개략도를 참조하면, 단일 파장의 He-Ne 레이저(Layer)를 시료 빔으로, 이 시료 빔을 이용하여 웨이퍼에 구현된 얼라인먼트 마크에서 반사되는 회절빔으로써, 마크의 위치를 검출하여 웨이퍼 얼라인먼트를 구현한다.Referring to the schematic diagram of the wafer alignment apparatus shown in FIG. 1, a He-Ne laser of a single wavelength is used as a sample beam and a diffraction beam reflected from an alignment mark implemented on a wafer using the sample beam. The position is detected to implement wafer alignment.
즉, 단일 파장의 He-Ne 레이저(Layer) 광원을 입사시키면, 도 1에 도시된 바와 같이 이 광원은 빔 스프리터(1)를 거치고 반사경(2)을 통해 입사되면, 도 2에 도시된 바와 같이 웨이퍼 상에 일정한 피치(pitch)의 웨이퍼 얼라인 마크가 형성된다. That is, when a single wavelength He-Ne laser (Layer) light source is incident, as shown in FIG. 1, the light source passes through the beam splitter 1 and is incident through the reflector 2, and as shown in FIG. 2. A constant pitch wafer alignment mark is formed on the wafer.
이후, 광원이 반사되는 경로는 도 1에 도시된 바와 같이 웨이퍼 얼라인 마크에서 도 3에 도시된 바와 같이 ±1차 및 ±2차 회절된 빔이 반사경(2)을 거치고 빔 스프리터(1)를 통해 검출기(detector)(3)에 제공되면, 검출기(3)는 도 4에 도시된 바와 같이 ±1차 및 ±2차 회절빔의 광량을 검출하여 오버레이를 구현할 수 있다.Then, the path where the light source is reflected is as shown in Figure 1 in the wafer alignment mark as shown in Figure 3 ± 1st and ± 2nd order diffracted beam passes through the reflector 2 and the beam splitter 1 When provided to the detector 3 through, the detector 3 can implement the overlay by detecting the amount of light of the ± 1st and ± 2nd order diffraction beams as shown in FIG.
그러나, 도 4에 도시된 바와 같이 ±1차 및 ±2차 회절빔의 광량을 검출하면서 오버레이를 구축해야 할 경우, 단일 파장의 He-Ne 레이저(Layer)를 2차에 걸쳐 입사시켜야 하는 번거로운 문제점이 있다.However, as shown in FIG. 4, when it is necessary to construct an overlay while detecting the amount of light of the ± 1st and ± 2nd diffraction beams, it is a cumbersome problem that a single wavelength He-Ne laser (Layer) is incident on the second order. There is this.
따라서, 본 발명은 상술한 문제점을 해결하기 위해 안출된 것으로서, 그 목적은 이중 파장 레이저를 한번에 입사시키고, 반사되는 2개의 파장에 대응하는 회절빔의 세기를 검출하여 레이어(layer)간 오버레이(overlay)를 향상시킬 수 있도록 하는 웨이퍼 정렬 방법을 제공함에 있다. Accordingly, the present invention has been made to solve the above-described problems, the object of which is to inject a dual-wavelength laser at once, detect the intensity of the diffraction beam corresponding to the two reflected wavelengths overlay between layers (overlay) It is to provide a wafer alignment method that can be improved).
상술한 목적을 달성하기 위하여 본 발명에서 이중 파장 레이저를 이용한 웨이퍼 정렬 방법은 얼라인먼트에 이용되는 이중 파장의 He-Ne 레이저(Layer) 광원을 입사하는 단계; 입사되는 광원에 따라 웨이퍼 상에 일정한 피치(pitch)의 웨이퍼 얼라인 마크가 형성되는 단계; 입사된 광원이 반사되는 경우, 얼라인먼트 장치 내 검출기에서 웨이퍼 얼라인 마크에서 첫 번째 파장에 대응하는 ±1차 및 ±2차 회절된 빔과, 두 번째 파장에 대응하는 ±1차 및 ±2차 회절된 빔의 광량을 검출하는 단계; 첫 번째 및 두 번째 파장에 대응하는 ±1차 및 ±2차 회절빔의 광량을 동시에 검출하여 측정의 정밀도와 신뢰도를 향상시켜 정밀한 오버레이를 구현할 수 있는 것을 특징으로 한다. In order to achieve the above object, the wafer alignment method using the dual wavelength laser in the present invention comprises the steps of: incident a He-Ne laser (Layer) light source of a dual wavelength used for alignment; Forming a wafer alignment mark with a constant pitch on the wafer according to the incident light source; When the incident light source is reflected, the first-order and ± second-order diffracted beam corresponding to the first wavelength and the first-order and ± second-order diffraction corresponding to the second wavelength in the wafer alignment mark at the detector in the alignment device Detecting an amount of light of the beam; By detecting the amount of light of ± 1st and ± 2nd order diffraction beams corresponding to the first and second wavelengths at the same time, it is possible to implement a precise overlay by improving the accuracy and reliability of the measurement.
이하, 첨부된 도면을 참조하여 본 발명에 따른 실시 예를 상세하게 설명하기로 한다.Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.
도 5는 본 발명에 따른 웨이퍼 얼라인먼트 장치에 대한 도면으로서, 이중 파장의 He-Ne 레이저(Layer), 또는 단일파장 레이저를 이중 파장 레이저로 변환하는 방식인 광음향 변조기(Acoustic Optic Modulator : 이하, AOM이라 함)를 시료 빔으로 사용하는데, 이러한 시료 빔을 웨이퍼 얼라인먼트 장치에 입사시킨다.FIG. 5 is a view illustrating a wafer alignment apparatus according to the present invention, wherein an Acoustic Optic Modulator (hereinafter referred to as AOM) converts a dual wavelength He-Ne laser or a single wavelength laser into a dual wavelength laser. A sample beam is incident on a wafer alignment apparatus.
그러면, 이중 파장의 광원 또는 AOM 시료 빔은 빔 스프리터(10)를 거치고 반사경(20)을 통해 입사되면, 웨이퍼 상에 일정한 피치(pitch)의 웨이퍼 얼라인 마크가 형성된다. Then, when the dual wavelength light source or the AOM sample beam passes through the beam splitter 10 and is incident through the reflector 20, a wafer pitch mark having a constant pitch is formed on the wafer.
이때, 입사되는 파장이 이중 파장의 광원임에 따라 2개의 파장이 2개의 웨이퍼 얼라인 마크에 각각 입사된다. At this time, as the incident wavelength is a dual wavelength light source, two wavelengths are respectively incident on the two wafer alignment marks.
이후, 이중 파장의 광원이 반사되는 경로는 도 5에 도시된 바와 같이 웨이퍼 얼라인 마크에서 첫 번째 파장에 대응하는 ±1차 및 ±2차 회절된 빔과, 두 번째 파장에 대응하는 ±1차 및 ±2차 회절된 빔이 반사경(20)을 거치고 빔 스프리터(10)를 통해 검출기(detector)(30)에 제공된다.Afterwards, the path where the dual wavelength light source is reflected is ± 1 order and ± 2 order diffracted beams corresponding to the first wavelength in the wafer alignment mark, and ± 1 order corresponding to the second wavelength, as shown in FIG. And ± 2nd order diffracted beam is passed through the reflector 20 and provided to the detector 30 through the beam splitter 10.
여기서, 광원의 회절은 수학식 1에 나타난 바와 같이, 회절 격자가 좁을 수록 회절 각이 크고 파장이 짧을 수록 회절 각이 작다. Here, as shown in Equation 1, the diffraction of the light source is narrower as the diffraction grating is narrower, and as the wavelength is shorter, the diffraction angle is smaller.
검출기(30)는 상이한 두 파장의 회절 각에 위치한 광 전류 변환 센서(sensor)로 구성되어 있는 것으로, 도 6에 도시된 바와 같이 첫 번째 파장에 대응하는 ±1차 및 ±2차 회절빔의 광량을 검출하며, 이어서, 두 번째 파장에 대응하는 ±1차 및 ±2차 회절빔의 광량을 검출하여 측정의 정밀도와 신뢰도를 향상시키며, 보다 정밀한 얼라인을 구현하여 오버레이를 향상시킬 수 있는 것이다. The detector 30 is composed of a photocurrent conversion sensor located at diffraction angles of two different wavelengths. As shown in FIG. 6, the amount of light of ± 1st and ± 2nd order diffraction beams corresponding to the first wavelength is shown. Then, by detecting the amount of light of the ± 1st and ± 2nd order diffraction beam corresponding to the second wavelength to improve the accuracy and reliability of the measurement, it is possible to implement a more precise alignment to improve the overlay.
그러므로, 본 발명은 이중 파장 레이저를 한번에 입사시키고, 반사되는 2개의 파장에 대응하는 회절빔의 세기를 검출함으로써, 측정의 정밀도와 신뢰도를 향상시키며, 보다 정밀한 얼라인을 구현하여 오버레이를 향상시킬 수 있는 효과가 있다. Therefore, the present invention can improve the accuracy and reliability of the measurement by implementing the dual wavelength laser at once and detecting the intensity of the diffraction beam corresponding to the two reflected wavelengths, and implement the more precise alignment to improve the overlay. It has an effect.
도 1은 종래 웨이퍼 얼라인먼트 장치의 개략도를 도시한 도면이고,1 is a view showing a schematic diagram of a conventional wafer alignment apparatus,
도 2는 웨이퍼 상에 일정한 피치(pitch)의 웨이퍼 얼라인 마크가 형성된 도면이며, FIG. 2 is a view in which a wafer align mark of a constant pitch is formed on a wafer;
도 3은 광량의 레이저 마크 및 회절광을 도시한 도면이며,3 is a diagram showing a laser mark and diffracted light of a light amount;
도 4는 단일 파장에 의한 ±1차 및 ±2차 회절빔의 광량의 세기를 도시한 도면이며, 4 is a view showing the intensity of light amount of ± 1st and ± 2nd diffraction beams by a single wavelength,
도 5는 본 발명에 따른 웨이퍼 얼라인먼트 장치의 개략도를 도시한 도면이며,5 is a schematic view of a wafer alignment apparatus according to the present invention;
도 6은 본 발명에 따른 이중 파장 레이저에 의한 ±1차 및 ±2차 회절빔의 광량의 세기를 도시한 도면이다. 6 is a view showing the intensity of the light amount of the ± 1st and ± 2nd order diffraction beams by the dual wavelength laser according to the present invention.
<도면의 주요부분에 대한 부호의 설명><Description of the symbols for the main parts of the drawings>
10 : 빔 스프리터 20 : 반사광10 beam splitter 20 reflected light
30 : 검출기30: detector
S1 : 단일 파장 레이저 S2 : 이중 파장 레이저S1: single wavelength laser S2: dual wavelength laser
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JPS6258628A (en) * | 1985-09-09 | 1987-03-14 | Nippon Telegr & Teleph Corp <Ntt> | Alignment process and device thereof |
JPH08213300A (en) * | 1995-02-01 | 1996-08-20 | Nikon Corp | Method and device for detecting position |
JPH0997758A (en) * | 1995-09-29 | 1997-04-08 | Nikon Corp | Aligning method |
KR100247699B1 (en) * | 1997-12-04 | 2000-03-15 | 김영환 | Variable diffractive exposure apparatus to align pattern |
KR20000027810A (en) * | 1998-10-29 | 2000-05-15 | 김영환 | Aligning apparatus for recognizing focus of pcb and the method thereof |
-
2002
- 2002-06-29 KR KR10-2002-0037529A patent/KR100481545B1/en not_active IP Right Cessation
Patent Citations (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPS6258628A (en) * | 1985-09-09 | 1987-03-14 | Nippon Telegr & Teleph Corp <Ntt> | Alignment process and device thereof |
JPH08213300A (en) * | 1995-02-01 | 1996-08-20 | Nikon Corp | Method and device for detecting position |
JPH0997758A (en) * | 1995-09-29 | 1997-04-08 | Nikon Corp | Aligning method |
KR100247699B1 (en) * | 1997-12-04 | 2000-03-15 | 김영환 | Variable diffractive exposure apparatus to align pattern |
KR20000027810A (en) * | 1998-10-29 | 2000-05-15 | 김영환 | Aligning apparatus for recognizing focus of pcb and the method thereof |
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