Preparation of lanthanide-containing precursors and deposition of lanthanide-containing films

Abstract

The disclosed lanthanide precursor compounds include a cyclopentadienyl ligand having at least one aliphatic group as a substituent and at least one bidentate ligand. These precursors are suitable for depositing lanthanide containing films.

Claims

1. A chemical having any one of formulae (a)-(c):
La(isopropyl-Cp).sub.2(thd),   a)
Er(methyl-Cp).sub.2(N.sup.EtO-DK), or   b)
Er(methyl-Cp).sub.2(N.sup.nPrO-DK),   c) wherein La is Lanthanum, Er is Erbium, Cp is Cyclopentadienyl, N.sup.EtO-DK is -(Et)N—C(Me)═CH—C(Me)═O, N.sup.nPrO-DK is -(nPr)N—C(Me)═CH—C(Me)═O, Et is ethyl, Me is methyl, nPr is n-propyl.

2. A composition suitable for use in chemical vapor deposition and/or atomic layer deposition for semiconductor manufacturing, the composition comprising the chemical of claim 1.

3. The composition of claim 2, wherein the chemical is 99% or more of the composition by weight.

4. A method of depositing a lanthanide-containing film, the method comprising a step of providing a vapor phase of the chemical of claim 1 to a chemical vapor deposition or atomic layer deposition process.

5. The method of claim 4, wherein the chemical vapor deposition or atomic layer deposition process produces a lanthanide-containing film on a substrate.

6. The method of claim 5, wherein the substrate is a semiconductor substrate.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) For a further understanding of the nature and objects for the present invention, reference should be made to the following detailed description, taken in conjunction with the accompanying drawings, in which like elements are given the same or analogous reference numbers and wherein:

(2) FIG. 1, which is a TGA graph illustrating the percentage of weight upon temperature increase; and

(3) FIG. 2 the onset temperature of melting (77° C.) and decomposition (410° C.) of the product were measured by Differential scanning calorimetry (DSC).

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

(4) The disclosed precursor compounds include a cyclopentadienyl ligand having at least one aliphatic group as a substituent and a bidentate ligand. The precursors have one of these three general formulas:
Ln(R.sub.1Cp)m(O—CR.sub.2═CH—CR.sub.2═O)n  1.
Ln(R.sub.1Cp)m(R.sub.3N—CR.sub.2═CH—CR.sub.2═O)n  2.
Ln(R.sub.1Cp)m(R.sub.3N—CR.sub.2═CH—CR.sub.2═NR.sub.3)n  3.

(5) In the above formulae 1-3, Ln=lanthanide series elements, La, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm , Yb, Lu. R.sub.1, R.sub.2 and R.sub.3 are each independently H or C.sub.1-C.sub.5 alkyl (straight or branched) chains. m=1 or 2 and n=1 or 2.

(6) The disclosed precursor compounds the above formulae 1-3 offer unique physical and chemical properties when compared to their corresponding homoleptic compounds, which include tris-substituted cyclopentadienyl lanthanide compounds, Ln(RCp)3 and tris-substituted beta-diketonate compounds, Ln(O—CR═CH—CR═O)3 (or Ln(R′N—CR═CH—CR═O)3, Ln(R′N—CR═CH—CR═NR′)3). Such properties include better control of steric crowding around the metal center, which in turn controls the surface reaction on the substrate and the reaction with a second reactant (such as an oxygen source). Independently fine tuning the substituents on the ligands increases volatility and thermal stability and decreases melting point to yield either liquids or low melting solids (having a melting point below approximately 105° C., preferably below about 80° C.).

(7) Properties of certain exemplary n o ecules and comparison n o ecules are summarized in Table 1.

(8) TABLE-US-00001 MW (g/mol) MP ° C. Phase at RT Er(tmsa).sub.3 648.81 172 Solid Er(thd).sub.3 717.08 186 Solid Er(Cp).sub.3 362.55 294 Solid Er(MeCp).sub.3 404.62 135 Solid Er(MeCp).sub.2(thd) 508.77 60 Solid Er(MeCp).sub.2(N.sup.EtO-DK) 451.67 Not measured Liquid Er(MeCp).sub.2(N.sup.nPrO-DK) 465.70 Not measured Liquid La(thd).sub.3 688.72 230 Solid La(tmsa).sub.3 620.06 150 Solid La(iPrCp).sub.2(thd) 536.52 77 Solid thd: —O—C(tBu)═CH—C(tBu)═O N.sup.EtO-DK: —(Et)N—C(Me)═CH—C(Me)═O N.sup.nPrO-DK: —(nPr)N—C(Me)═CH—C(Me)═O

WORKING EXAMPLES

Example 1—Synthesis of Lanthanum Isopropylcyclopentadienyl tetramethylheptanedionate=La(iPrCp).SUB.2.(thd)

(9) A solution of 2,2,6,6,-tetramethyl-3,5-heptanedione (2 g, 10.8 mmol) in 30 mL of toluene was added dropwise to a solution of La(iPrCp).sub.3 (5 g, 10.8 mmol) in 15 mL of toluene at −78° C. The reaction mixture was warmed slowly to room temperature with stirring overnight. After filtration, the solvent was removed under reduced pressure to obtain a brown solid. The brown solid was sublimed at ˜180° C. under 35 mTorr to produce a yellow solid about 44% (2.54 g) yields,

(10) The purified product left a 5.4% residual mass during open-cup TGA analysis measured at a temperature rising rate of 10° C./min in an atmosphere which flows nitrogen at 200 mL/min. These results are shown in FIG. 1, which is a TGA graph illustrating the percentage of weight upon temperature increase. Onset temperature of melting (77° C.) and decomposition (410° C.) of the product were measured by Differential scanning calorimetry (DSC), which are shown in FIG. 2.

Notations and Nomenclature

(11) While the invention has been described in conjunction with specific embodiments thereof, it is evident that many alternatives, modifications, and variations will be apparent to those skilled in the art in light of the foregoing description. Accordingly, it is intended to embrace all such alternatives, modifications, and variations as fall within the spirit and broad scope of the appended claims. The present invention may suitably comprise, consist or consist essentially of the elements disclosed and may be practiced in the absence of an element not disclosed. Furthermore, if there is language referring to order, such as first and second, it should be understood in an exemplary sense and not in a limiting sense. For example; it can be recognized by those skilled in the art that certain steps can be combined into a single step.

(12) The singular forms “a”, “an” and “The” include plural referents; unless the context clearly dictates otherwise.

(13) “Comprising” in a claim is an open transitional term which means the subsequently identified claim elements are a nonexclusive listing (i.e., anything else may be additionally included and remain within the scope of “comprising”). “Comprising” as used herein may be replaced by the more limited transitional terms “consisting essentially of” and “consisting of” unless otherwise indicated herein.

(14) “Providing” in a claim is defined to mean furnishing, supplying, making available, or preparing something. The step may be performed by any actor in the absence of express language in the claim to the contrary.

(15) Optional or optionally means that the subsequently described event or circumstances may or may not occur. The description includes instances where the event or circumstance occurs and instances where it does not occur.

(16) Ranges may be expressed herein as from about one particular value, and/or to about another particular value. When such a range is expressed, it is to be understood that another embodiment is from the one particular value and/or to the other particular value, along with all combinations within said range.

(17) All references identified herein are each hereby incorporated by reference into this application in their entireties, as well as for the specific information for which each is cited.

(18) It will be understood that many additional changes in the details, materials, steps and arrangement of parts, which have been herein described in order to explain the nature of the invention, may be made by those skilled in the art within the principle and scope of the invention as expressed in the appended claims. Thus, the present invention is not intended to be limited to the specific embodiments in the examples given above.