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US-12624287-B2 - Composition for the selective etching of silicon

US12624287B2US 12624287 B2US12624287 B2US 12624287B2US-12624287-B2

Abstract

Silicon etching compositions are described and may be used for selectively etching silicon with respect to a metal film. In particular, the silicon etching compositions can be used to improve the selective etching ratio of silicon from the surface of a semiconductor on which the metal film and silicon are exposed.

Inventors

  • Jeong Sik OH
  • Tae Ho Kim
  • Gi Young Kim
  • Myung Ho Lee
  • Myung Geun Song
  • Pilgu Kang
  • Youngmee Kang
  • Eunseok OH

Assignees

  • ENF TECHNOLOGY CO., LTD.
  • SK Hynix Inc.

Dates

Publication Date
20260512
Application Date
20220906
Priority Date
20210913

Claims (20)

  1. 1 . A composition for selective etching of silicon, comprising: about 0.5 to about 10% by weight of a fluorine compound; about 30 to about 55% by weight of nitric acid (HNO 3 ); about 1 to about 8% by weight of acetic acid (CH 3 COOH); about 5 to about 15% by weight of phosphoric acid (H 3 PO 4 ); and about 0.001 to about 10% by weight of an organic amine compound, wherein the organic amine compound comprises one or more of polyethyleneimine, octylamine, polypropyleneimine, pentaethylenehexamine, N,N′-bis(2-aminoethyl)-1,3-propanediamine, N-(2-aminoethyl)-1,3-propanediamine, N-(3-aminopropyl)-1,3-propanediamine, spermine, spermidine, 1,4-bis(3-aminopropyl)piperazine, 1-(2-aminoethyl)piperazine, tris(2-aminoethyl)amine, branched or dendritic polyamidoamine, dendritic poly(propyleneimine) (DAB-am-16), poly(L-lysine) and chitosan.
  2. 2 . The composition for selective etching of silicon according to claim 1 , wherein the fluorine compound comprises one or more of hydrofluoric acid, ammonium bifluoride, sodium fluoride, potassium fluoride, aluminum fluoride, fluoroboric acid, ammonium fluoride, sodium bifluoride, potassium bifluoride, and ammonium tetrafluoroborate.
  3. 3 . The composition for selective etching of silicon according to claim 1 , wherein the organic amine compound has a molecular weight Mw of 300 to 20,000.
  4. 4 . The composition for selective etching of silicon according to claim 1 , wherein the etch rate of silicon is 3 μm/min or more, and the etch selectivity of silicon to a metal film is 100 or more.
  5. 5 . The composition for selective etching of silicon according to claim 1 , wherein the etch selectivity of silicon to a metal film is from about 100 to about 1200.
  6. 6 . The composition for selective etching of silicon according to claim 1 , wherein the fluorine compound comprises hydrofluoric acid.
  7. 7 . The composition for selective etching of silicon according to claim 1 , wherein the organic amine compound comprises polyethyleneimine, octylamine, or a combination thereof.
  8. 8 . The composition for selective etching of silicon according to claim 1 , further comprising water.
  9. 9 . The composition for selective etching of silicon according to claim 1 , wherein the composition is free of water.
  10. 10 . The composition for selective etching of silicon according to claim 1 , wherein the composition comprises nitric acid and acetic acid in a ratio from about 3 to about 15.
  11. 11 . The composition of claim 1 , wherein the composition comprises at least 90% by weight of acid.
  12. 12 . The composition for selective etching of silicon according to claim 1 , wherein the composition comprises from 6 to about 15% by weight of phosphoric acid (H 3 PO 4 ).
  13. 13 . The composition for selective etching of silicon according to claim 1 , wherein the composition selectively etches silicon relative to a metal film.
  14. 14 . The composition for selective etching of silicon according to claim 13 , wherein the metal film comprises one or more of tungsten (W), titanium nitride (TiN), titanium (Ti), gold (Au), molybdenum (Mo), nickel (Ni), palladium (Pd), and platinum (Pt).
  15. 15 . The composition for selective etching of silicon according to claim 13 , wherein the metal film comprises tungsten (W).
  16. 16 . A semiconductor device manufactured using the composition for selective etching of silicon of claim 1 .
  17. 17 . A method for preparing a composition for selective etching of silicon, comprising mixing: 0.5 to 10% by weight of a fluorine compound; 30 to 55% by weight of nitric acid (HNO 3 ); 1 to 8% by weight of acetic acid (CH 3 COOH); 5 to 15% by weight of phosphoric acid (H 3 PO 4 ); and 0.001 to 10% by weight of an organic amine compound, wherein the organic amine compound comprises one or more of polyethyleneimine, octylamine, polypropyleneimine, pentaethylenehexamine, N,N′-bis(2-aminoethyl)-1,3-propanediamine, N-(2-aminoethyl)-1,3-propanediamine, N-(3-aminopropyl)-1,3-propanediamine, spermine, spermidine, 1,4-bis(3-aminopropyl)piperazine, 1-(2-aminoethyl)piperazine, tris(2-aminoethyl)amine, branched or dendritic polyamidoamine, dendritic poly(propyleneimine) (DAB-am-16), poly(L-lysine) and chitosan.
  18. 18 . The method of claim 17 , wherein a ratio of the nitric acid to the acetic acid is from about 3 to about 15% by weight.
  19. 19 . The method of claim 17 , wherein the composition comprises at least 90% by weight of acid.
  20. 20 . The method of claim 17 , further comprising mixing water such that the total weight of the composition is 100%.

Description

CROSS REFERENCE TO RELATED APPLICATIONS This application claims the benefits of priority to Korean Patent Application No. 10-2021-0121626, filed Sep. 13, 2021, incorporated herein by reference. TECHNICAL FIELD The present invention relates to a composition for selectively etching silicon on a surface on which a metal film and silicon (Si) are exposed. BACKGROUND ART Tungsten (W) is used as a representative plug metal in the semiconductor field. Meanwhile, an acidic etchant of silicon comprises etching species such as hydrofluoric acid and oxidizing species such as nitric acid and sulfuric acid, for example. The acidic etchant has a problem in that the defect rate increases because of the low selectivity of silicon with respect to the tungsten film in the silicon bulk etching of the semiconductor manufacturing process. In particular, as a metal such as tungsten is etched non-selectively, a detect may occur in a subsequent process such as the exposed lower pattern and a short circuit. This problem of the acidic etchant is a limiting factor in the application of the acidic etchant in processes such as semiconductor packaging and Through Silicon Via (TSV). Therefore, it is necessary to study a composition that has a very low etch rate of the metal film and can selectively etch only silicon. DETAILED DESCRIPTION OF THE INVENTION Technical Problem It is an object of the present invention to provide a composition having the improved etch selectivity of silicon to a metal film. Solution to Problem In order to solve the above problems, the present invention provides a composition for selective etching of silicon, comprising: a fluorine compound;nitric acid;acetic acid;phosphoric acid; andan organic amine compound. According to one embodiment, the fluorine compound may comprise one or more of hydrofluoric acid, ammonium bifluoride, sodium fluoride, potassium fluoride, aluminum fluoride, fluoroboric acid, ammonium fluoride, sodium bifluoride, potassium bifluoride, and ammonium tetrafluoroborate. According to one embodiment, the organic amine compound may comprise one or more of polyethyleneimine, octylamine, polypropyleneimine, pentaethylenehexamine, N,N′-bis(2-aminoethyl)-1,3-propanediamine, N-(2-aminoethyl)-1,3-propanediamine, N-(3-aminopropyl)-1,3-propanediamine, spermine, spermidine, 1,4-bis(3-aminopropyl)piperazine, 1-(2-aminoethyl)piperazine, tris(2-aminoethyl)amine, branched or dendritic polyamidoamine, dendritic poly(propyleneimine) (DAB-am-16), poly(L-lysine) and chitosan. According to one embodiment, the organic amine compound may comprise polyethyleneimine According to one embodiment, the organic amine compound may have a molecular weight Mw of 300 to 20,000. According to one embodiment of the present invention, the etch rate of silicon may be 3 μm/min or more, and the etch selectivity of silicon to the metal film may be 100 or more. According to other embodiment of the present invention, there is provided a method for preparing a composition for selective etching of silicon, comprising mixing: 0.5 to 10% by weight of a fluorine compound;15 to 55% by weight of nitric acid;1 to 20% by weight of acetic acid;5 to 15% by weight of phosphoric acid; and0.001 to 10% by weight of an organic amine compound. According to another embodiment of the present invention, there is provided a semiconductor device manufactured using the composition for selective etching of silicon as described above. The specific details of other embodiments according to the present invention are included in the detailed description below. Effect of the Invention According to the present invention, it is possible to improve etch selectivity of silicon on the semiconductor surface on which both of a metal film and silicon are exposed. Best Mode for Carrying out the Invention The present invention may have various modification and various embodiments, and specific embodiments will be illustrated and described in detail. However, it is not intended to limit the present invention to specific embodiments, and should he understood to include all modifications, equivalents, and substitutes included in the spirit and scope of the present invention. In describing the present invention, if it is determined that a detailed description of a related known technology may obscure the gist of the present invention, the detailed description thereof will be omitted. As used herein, unless otherwise specified, the expression “to” in relation to a number is used as an expression including the corresponding numerical value. Specifically, for example, the expression “1 to 2” is meant to include all numbers between 1 and 2 as well as 1 and 2. In a semiconductor, silicon is oxidized to a silicon oxide film by oxidizing species generated from an oxidizing agent and an auxiliary oxidizing agent. The oxidized silicon oxide film is etched by contact with an etchant. When etching silicon, it is necessary to consider the selective etching amount of silicon to the metal fi