• 专利附录
  • 专利说明
  • 权利要求
  • 类似技术
  • 同族专利
  • 引用文献
  • 法律状态
  • 优先权
    • 专利摘要:
    PURPOSE: A wafer aligning method using a double wavelength laser is provided to be capable of improving the overlay state between layers. CONSTITUTION: A double wavelength He-Ne laser light source is incident. A plurality of wafer align marks having a constant pitch, are formed at the upper portion of a wafer according to the incident light source. When the incident light source is reflected from the wafer align marks, the quantities of light for the first ±1 and ±2 order diffraction beams corresponding to the first wavelength of the light source and the second ±1 and ±2 order diffraction beams corresponding to the second wavelength, are detected by using a detector(30) installed at the inner portion of an alignment apparatus. At this time, the quantities of light for the first ±1 and ±2 order diffraction beams corresponding to the first and second wavelength, are simultaneously detected for improving precision and reliability.
    公开号:KR20040003164A
    申请号:KR1020020037529
    申请日:2002-06-29
    公开日:2004-01-13
    发明作者:김상원；이용석
    申请人:동부전자 주식회사；
    IPC主号:
    专利说明:

    Wafer alignment method using a dual wavelength laser {METHOD FOR WAFER ALIGNMENT BY USING DOUBLE WAVELENGTH LASER}
    [11] 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.
    [12] 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.
    [13] Such layer overlap should be implemented with precise overlay, which must be preceded by precise wafer alignment.
    [14] 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.
    [15] 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.
    [16] 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.
    [17] 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.
    [18] 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).
    [19] 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.
    [1] 1 is a view showing a schematic diagram of a conventional wafer alignment apparatus,
    [2] FIG. 2 is a view in which a wafer align mark of a constant pitch is formed on a wafer;
    [3] 3 is a diagram showing a laser mark and diffracted light of a light amount;
    [4] 4 is a view showing the intensity of light amount of ± 1st and ± 2nd diffraction beams by a single wavelength,
    [5] 5 is a schematic view of a wafer alignment apparatus according to the present invention;
    [6] 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.
    [7] <Description of the symbols for the main parts of the drawings>
    [8] 10 beam splitter 20 reflected light
    [9] 30: detector
    [10] S1: single wavelength laser S2: dual wavelength laser
    [20] Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.
    [21] 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.
    [22] 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.
    [23] At this time, as the incident wavelength is a dual wavelength light source, two wavelengths are respectively incident on the two wafer alignment marks.
    [24] 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.
    [25] 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.
    [26]
    [27] 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.
    [28] 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.
    权利要求:
    Claims (4)
    [1" claim-type="Currently amended] In the wafer alignment method in the wafer alignment device,
    Entering a dual wavelength He-Ne laser (Layer) light source used for the alignment;
    Forming a wafer alignment mark of a predetermined 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 in the wafer alignment mark at the detector in the alignment device, and ± first-order and ± corresponding to the second wavelength Detecting the amount of light in the second diffracted beam;
    Alignment of wafers using dual wavelength lasers can be realized by simultaneously detecting the amount of light of the ± 1st and ± 2nd diffraction beams corresponding to the first and second wavelengths, thereby improving the accuracy and reliability of the measurement Way.
    [2" claim-type="Currently amended] The method of claim 1,
    The incident light source is a wafer alignment method using a dual-wavelength laser, characterized in that for using the optical acoustic modulator (Acoustic Optic Modulator) for converting a single wavelength laser to a dual-wavelength laser as a sample beam.
    [3" claim-type="Currently amended] The method of claim 2,
    The wavelength of the incident light source is a dual wavelength light source, the two wavelengths of the wafer alignment method using a dual wavelength laser, characterized in that each incident to two wafer alignment marks.
    [4" claim-type="Currently amended] The method of claim 1,
    And said detector comprises a photocurrent conversion sensor positioned at diffraction angles of two different wavelengths.
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    同族专利:
    公开号 | 公开日
    KR100481545B1|2005-04-07|
    引用文献:
    公开号 | 申请日 | 公开日 | 申请人 | 专利标题
    法律状态:
    2002-06-29|Application filed by 동부전자 주식회사
    2002-06-29|Priority to KR10-2002-0037529A
    2004-01-13|Publication of KR20040003164A
    2005-04-07|Application granted
    2005-04-07|Publication of KR100481545B1
    优先权:
    申请号 | 申请日 | 专利标题
    KR10-2002-0037529A|KR100481545B1|2002-06-29|2002-06-29|Method for wafer alignment by using double wavelength laser|
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