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KR-20260066479-A - Pellicle for EUV lithography with Radical Resistive Layer

KR20260066479AKR 20260066479 AKR20260066479 AKR 20260066479AKR-20260066479-A

Abstract

A pellicle for extreme ultraviolet lithography comprises a pellicle portion through which extreme ultraviolet exposure light is transmitted and a support portion that supports the pellicle portion. The pellicle portion has a radical-resistant layer formed of a material containing silicon (Si) and carbon (C). Since the resistance of the pellicle portion to hydrogen radicals present in the EUV scanner is enhanced, damage to the pellicle portion or a decrease in transmittance caused by hydrogen radicals does not occur.

Inventors

  • 윤종원
  • 박민규
  • 우미경
  • 양철규

Assignees

  • 주식회사 에스앤에스텍

Dates

Publication Date
20260512
Application Date
20241104

Claims (20)

  1. A pellicle for extreme ultraviolet lithography comprising a pellicle portion through which extreme ultraviolet exposure light is transmitted, and a support portion that supports the pellicle portion, A pellicle for extreme ultraviolet lithography characterized in that the pellicle portion comprises a radical-resistant layer formed of a material including silicon (Si) and carbon (C).
  2. In Article 1, A pellicle for extreme ultraviolet lithography characterized in that the Si content included in the radical-resistant layer exceeds 40 at% and is less than 55 at%.
  3. In Article 1, A pellicle for extreme ultraviolet lithography characterized in that the radical-resistant layer further comprises one or more of nitrogen (N) and boron (B).
  4. In Paragraph 3, A pellicle for extreme ultraviolet lithography characterized in that the radical-resistant layer has a SiC content exceeding 70 at% and a total content of N and B of less than 30 at%.
  5. In Paragraph 3, The nitrogen (N) and boron (B) in the above radical-resistant layer have a content ratio of N:B = 4:6 to 6:4, and A pellicle for extreme ultraviolet lithography characterized in that the radical-resistant layer has a SiC content of less than 70 at% and greater than 10%, and a total content of N and B of greater than 30 at% and less than 90 at%.
  6. In Article 1 or Article 3, A pellicle for extreme ultraviolet lithography characterized in that the radical-resistant layer further comprises one or more of beryllium (Be), fluorine (F), phosphorus (P), sulfur (S), and chlorine (Cl).
  7. In Article 6, A pellicle for extreme ultraviolet lithography characterized in that the SiC content of the radical-resistant layer exceeds 70 at%.
  8. A pellicle for extreme ultraviolet lithography comprising a pellicle portion through which extreme ultraviolet exposure light is transmitted, and a support portion that supports the pellicle portion, A pellicle for extreme ultraviolet lithography characterized in that the pellicle portion comprises a radical-resistant layer formed from a material containing two or more of boron (B), nitrogen (N), beryllium (Be), fluorine (F), phosphorus (P), sulfur (S), and chlorine (Cl).
  9. In Article 8, A pellicle for extreme ultraviolet lithography characterized in that the radical-resistant layer is formed from a material containing BN or a material containing PN.
  10. In Article 9, A pellicle for extreme ultraviolet lithography characterized in that the radical-resistant layer is formed from one of BN, BNC, BNS, PN, P3N5, and PNC.
  11. In Article 1 or Article 8, A pellicle for extreme ultraviolet lithography characterized in that the pellicle portion is composed of a single layer of the radical-resistant layer.
  12. In Article 11, A pellicle for extreme ultraviolet lithography characterized by the radical-resistant layer having a thickness of 15 to 50 nm.
  13. In Article 1 or Article 8, The above pellicle part is, A central layer composed of the above radical-resistant layer and for securing transmittance for EUV exposure light, and A capping layer disposed on one or more of the upper and lower portions of the above central layer, A pellicle for extreme ultraviolet lithography characterized by including
  14. In Article 13, A pellicle for extreme ultraviolet lithography characterized in that the capping layer comprises a metal silicide.
  15. In Article 13, A pellicle for extreme ultraviolet lithography characterized by the radical-resistant layer having a thickness of 10 to 30 nm.
  16. In Article 1 or Article 8, The above pellicle part is, A central layer for securing transmittance for EUV lithography light, and A capping layer composed of the above radical-resistant layer and disposed on one or more of the upper and lower parts of the above central layer, A pellicle for extreme ultraviolet lithography characterized by including
  17. In Article 16, A pellicle for extreme ultraviolet lithography characterized in that the capping layer comprises a metal silicide.
  18. In Article 16, A pellicle for extreme ultraviolet lithography characterized by the radical-resistant layer having a thickness of 2 to 10 nm.
  19. In Article 1 or Article 8, A pellicle for extreme ultraviolet lithography characterized in that the above-mentioned pellicle portion is configured such that a plurality of the above-mentioned radical-resistant layers and a plurality of auxiliary layers are alternately arranged.
  20. In Article 19, A pellicle for extreme ultraviolet lithography characterized by the radical-resistant layer having a thickness of 2 to 5 nm.

Description

Pellicle for EUV lithography with Radical Resistive Layer The present invention relates to a pellicle, and more specifically, to an extreme ultraviolet lithography pellicle mounted on an EUV photomask used in EUV lithography. In the EUV lithography process using 13.5 nm wavelength EUV (Extreme Ultra-Violet) exposure light, a method of attaching a pellicle to the photomask is used to prevent impurities from adhering to the surface of the photomask. Recently, as circuit line widths have become finer, the size of impurities that can affect pattern damage has also decreased, making the role of the pellicle for photomask protection even more important. FIG. 1 is a diagram illustrating the basic structure of a pellicle for general extreme ultraviolet lithography. The pellicle (100) is composed of a pellicle portion (20) and a support portion (10). The pellicle portion (20) functions to transmit extreme ultraviolet exposure light of a wavelength of 13.5 nm. The support portion (10) functions to support the pellicle portion (20). The support portion (10) is formed by etching the substrate after the pellicle portion (20) is formed on a transparent substrate. A photomask equipped with a pellicle (100) having the above structure is installed in an exposure machine and used to expose a wafer. As the EUV scanner in the exposure machine irradiates the photomask with EUV exposure light of a wavelength of 13.5 nm, the photomask reflects the patterned exposure light, and thereby the patterned EUV exposure light is irradiated onto the wafer. A large amount of hydrogen radicals exists in EUV scanners where photomasks are used. The pellicle (100) mounted on the photomask is exposed to such an environment of large amounts of hydrogen radicals. These hydrogen radicals cause damage to the pellicle portion (20), resulting in a decrease in transmittance and durability of the pellicle portion (20). Therefore, it is required to manufacture a pellicle portion (20) that is highly resistant to hydrogen radicals. Figure 1 is a diagram illustrating the basic structure of a pellicle for general extreme ultraviolet lithography. FIG. 2 is a graph showing the atomic radii of a plurality of materials in relation to the material constituting the radical-resistant layer of the present invention. FIGS. 3 to 7 are drawings showing various embodiments of a pellicle part having a radical-resistant layer according to the present invention. The present invention will be described in more detail below with reference to the drawings. The configuration of a general pellicle (100) as illustrated in FIG. 1, that is, the configuration of a pellicle (100) having a pellicle part (20) and a support part (10), is the same in the present invention. Therefore, specific descriptions of these configurations are omitted, and the description of FIG. 1 is used as a description of the present invention, and the same reference numerals are used to cite them. A radical refers to a state in which an odd number of electrons exist in orbitals that can be occupied. Therefore, hydrogen radicals exist in two main types. 1) Hydrogen atom: Hydrogen has atomic number 1, and if it exists in an atomic state, it is a radical itself. 2) Ionized hydrogen molecule: If H₂ is ionized (by removing one electron) to become H₂ +, it becomes a radical with one electron. The penetration of radicals into a thin film occurs more easily as the atomic weight decreases, or more precisely, as the size of the atom decreases or the bond radius of the molecule decreases. In the prior art, the pellicle portion (20) is generally composed of a thin film containing a layer of material containing a transition metal, such as a MoSi layer. It is believed that hydrogen atoms among the forms of hydrogen radicals are the main cause of penetration into a layer of material containing a transition metal. Therefore, a fundamental method to prevent damage to the thin film by hydrogen radicals is to form the thin film with a material that is difficult for hydrogen atoms to penetrate. The pellicle portion (20) of the present invention is formed of a material that makes it difficult for hydrogen radicals present in the EUV scanner to penetrate. Below, a material for implementing such a pellicle portion (20) is described. In order to prevent the penetration of hydrogen atoms, the potential barrier formed by the atoms within the pellicle (20) must be high, and for this to be advantageous, the bond distance between atoms, that is, the atomic radius, must be short. FIG. 2 shows the atomic radii for various elements. In FIG. 2, the horizontal dotted line indicates the atomic radius of a transition metal, and elements below this line (hereinafter referred to as the 'baseline') have atomic radii smaller than those of a transition metal. Therefore, if elements below the baseline are used as constituent materials of the pellicle part (20), a higher potential barrier can be achieved than that of a conventional pellicle part (20).