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KR-102962981-B1 - Method for depositing molybdenum or tungsten material

KR102962981B1KR 102962981 B1KR102962981 B1KR 102962981B1KR-102962981-B1

Abstract

Provided is a method for the rapid deposition of a highly conformal molybdenum- or tungsten-containing film on a microelectronic device substrate under vapor deposition conditions. In practice of the present invention, a nucleation step is first performed using a lower metal precursor concentration than is typically used in the reaction zone. This use of a lower metal precursor concentration can be achieved by controlling the temperature of the ampoule (containing the precursor), the concentration of the precursor, the pressure in the reaction zone, and the pulse duration. In this manner, the lower concentration is generally used to form a nucleation layer of about 3 Å or more, or about 9, 15, or 25 Å or less, at which point the conditions for introducing the precursor are favorably changed, and the concentration of the precursor in the reaction zone is increased for the purpose of bulk deposition.

Inventors

  • 라이트 로버트 엘

Assignees

  • 엔테그리스, 아이엔씨.

Dates

Publication Date
20260511
Application Date
20220506
Priority Date
20210507

Claims (15)

  1. A method of vapor depositing a molybdenum or tungsten-containing film on a surface, and Introducing a first precursor of molybdenum or tungsten at a first precursor concentration and a reducing gas into a reaction zone including the surface until a film having a thickness of 3 Å to 25 Å is deposited on the surface; Introducing a second precursor of molybdenum or tungsten at a second precursor concentration and a reducing gas into a reaction zone until deposition of a film having a desired thickness is achieved. It includes, wherein the concentration of the first precursor is 1 to 75% of the concentration of the second precursor in the reaction zone, and the first precursor and the second precursor may both be the same precursor or different precursors, Here, the first precursor is placed in an ampoule before being introduced into the reaction zone, and the ampoule is maintained at a temperature of 40°C to 70°C. method.
  2. A method according to claim 1, wherein the concentration of the first precursor is 10 to 50% of the concentration of the second precursor.
  3. A method for vapor depositing a molybdenum or tungsten-containing film on the surface of a microelectronic device in a reaction zone operated at a pressure of 1 to 1000 Torr and a temperature of 300°C to 1000°C, wherein the surface is selected from nitrides, oxides, metals, semiconductors, and superconductors, and said method a. While continuously introducing a reducing gas into a reaction zone including the surface until a film having a thickness of 3 Å to 25 Å is deposited, a molybdenum or tungsten precursor is repeatedly introduced into the reaction zone including the surface in a pulsed manner for a period of 0.1 to 120 seconds, followed by a pause for 1 to 120 seconds, wherein the first concentration of the precursor in the reaction zone is 1 to 5000 ppm at the peak, and b. While continuously introducing a reducing gas into a reaction zone including the surface until a film having a desired thickness is deposited, a molybdenum or tungsten precursor is repeatedly introduced into the reaction zone including the surface in a pulsed manner for a period of 0.1 to 120 seconds to reach a second precursor concentration, and then stopped for 1 to 120 seconds, wherein the second concentration of the precursor in the reaction zone is 1.3 to 100 times the first precursor concentration. A method that includes
  4. A method according to claim 3, wherein the precursor is selected from WCl 6 , WCl 5 , WOCl 4 , MoO 2Cl 2 , MoCl 5 , and MoOCl 4 .
  5. A method for vapor depositing a molybdenum or tungsten-containing film on the surface of a microelectronic device in a reaction zone operated at a pressure of 1 to 1000 Torr and a temperature of 300°C to 1000°C, wherein the surface is selected from nitrides, oxides, metals, semiconductors, and superconductors, and said method a. While continuously introducing a reducing gas into a reaction zone including the surface until a film having a thickness of 3 Å to 25 Å is deposited, a molybdenum or tungsten precursor is continuously introduced into a reaction zone including the surface, wherein a first concentration of the precursor in the reaction zone is 1 to 5000 ppm at a peak, and b. While continuously introducing a reducing gas into a reaction zone including the surface until a film having a desired thickness is deposited, a molybdenum or tungsten precursor is continuously introduced into a reaction zone including the surface to reach a second precursor concentration, wherein the second concentration of the precursor in the reaction zone is 1.3 to 100 times the first precursor concentration. A method that includes
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Description

Method for depositing molybdenum or tungsten material The present invention relates to the vapor deposition of molybdenum or tungsten-containing materials on a microelectronic substrate. Due to their characteristics of extremely high melting points, low coefficient of thermal expansion, low resistivity, and high thermal conductivity, molybdenum and tungsten are increasingly being used in the manufacture of semiconductor devices, including in diffusion barriers, electrodes, photomasks, power electronics substrates, low-resistivity gates, and wiring. Such utility has stimulated efforts to achieve the deposition of molybdenum and tungsten films in applications characterized by high conformality of the deposited films and high deposition rates that enable efficient high-volume fabrication. This, in turn, has stimulated efforts to develop improved molybdenum and tungsten source reactants useful in vapor deposition operations, as well as improved method parameters utilizing such reactants. Furthermore, difficulties are often encountered in the deposition of molybdenum on specific substrates such as metals, metal nitrides, dielectric materials (oxides), semiconductors, and superconductors, as deposition delays can often be associated with difficulties in establishing nucleation on the substrate surface prior to the desired layer-on-layer deposition. When the deposition temperature is reduced, the overall deposition rate generally decreases, and sensitivity to various substrate surfaces is generally more pronounced. There remains a need to achieve the deposition of molybdenum and tungsten-containing materials using higher deposition rates that enable efficient high-volume manufacturing operations. Figure 1 is a scanning electron microscope (SEM) image of a nominally exposed titanium nitride surface with a mass equivalent thickness of 1.6 Å Mo, prepared by chemical vapor deposition (CVD) of Mo using MoO₂Cl₂ as a precursor. The substrate temperature was 450°C. Figure 2 is an SEM of a (comparative) example of molybdenum chemical vapor deposition using MoO₂Cl₂ on titanium nitride at a substrate temperature of 400°C. This example shows poor nucleation with a mass equivalent thickness of 9.9 Å Mo on the surface, with only the molybdenum oxide phase revealed by X-ray diffraction. FIG. 3 is an SEM showing the deposition/nucleation of molybdenum on a titanium nitride substrate using the method of the present invention (and a substrate temperature of 390°C). The Mo film has a mass equivalent thickness of 9.4 Å (see Example 1 below). Figure 4 is an SEM of a film prepared using nucleation step conditions for an extended number of cycles, which produces a slightly thicker Mo film on the via structure to show the excellent conformality of the film. Figure 5 is an SEM of a Mo film with a mass equivalent thickness of 104 Å deposited on a PVD Mo substrate. The CVD conditions were as follows: T sub = 390°C, low precursor concentration 30 ppm. These data show that the PVD Mo substrate is an initiation surface similar to the Mo nucleation stage prior to bulk Mo deposition. Figure 6 is an SEM of a Mo film with a mass equivalent thickness of 102 Å deposited by CVD on a TiN substrate. Deposition conditions: T sub = 450°C, precursor concentration = 37 ppm. This is close to the lower limit of substrate temperature at which such a concentration enables the deposition of Mo on TiN. Figure 7 is an SEM of a Mo film deposited in two steps on a TiN substrate. The mass equivalent thickness of Mo is 108 Å. The deposition temperature was T sub = 390°C; the pulsed CVD nucleation layer used a low precursor concentration of 22 ppm; and the bulk CVD deposition used a precursor concentration of 30 ppm. These data demonstrate that the Mo nucleation step is formed in a manner suitable for bulk Mo deposition (an initiation surface similar to the PVD Mo substrate). Figure 8 is a plot of TiN etching in Å versus H₂ flow rate (sccm). Such data shows that increasing the H₂ flow rate reduces the precursor concentration, illustrating how reducing the concentration during the nucleation step can reduce substrate (TiN) etching. Figure 9 is a comparison of the CVD molybdenum deposition rates on titanium nitride substrates and PVD molybdenum substrates as a function of deposition time. Substrate temperature = 650°C, pressure = 80 Torr, argon carrier gas flow rate = 50 sccm, hydrogen co-reactant gas flow rate = 4000 sccm. The graph shows the effect of nucleation retardation on the deposition rate. The graph also shows that the molybdenum deposition rate on titanium nitride increased by at least 25% over a period of 300 to 600 seconds when deposited on Mo compared to a TiN substrate. Precursor concentration = 20 ppm. As used in this specification and the appended claims, the singular form includes the plural unless explicitly otherwise indicated in the content. As used in this specification and the appended claims, the term “or” is generally used in its meaning includi