KR100600468B1 - Process for producing cycloalkene copper precursors - Google Patents

Abstract

A method of forming a volatile copper precursor for chemical vapor deposition of a copper thin film is (nRm-cyclohexene) Cu (I) (hfac) (wherein n, m = 1-6) or (nRm-cyclopentene) Cu (I formation of a volatile liquid having the formula of (hfac), where n, m = 1-5, wherein R is alkyl such as methyl and ethyl.

Description

Process for producing cycloalkene copper precursor {PROCESS FOR PRODUCING CYCLOALKENE COPPER PRECURSORS}

The present invention relates to the synthesis of volatile liquid copper precursors and their application in chemical vapor deposition of copper metal thin films.

)및 높은 전자이동(electromigration) 저항성 때문에, 구리금속 박막재료가 집적회로내 금속 배선(interconnections)으로 사용하기에 이상적이라고 생각된다.In recent years, chemical vapor deposition of copper metal thin films has attracted great attention. Its low resistance (~ 1.7

And the high electromigration resistance, it is believed that copper metal thin film materials are ideal for use as metal interconnections in integrated circuits.

), 표면구조에 대한 뛰어난 적합성, 그리고 우수한 전자이동 저항성을 가지고 있어야한다. 일반적으로 고온에서 수행되는 CVD 공정에서, 구리 전구체는 합리적인 증착속도를 달성하기에 충분한 증기압을 가지고 있어야 하며, 또한 CVD 액체 운반라인 또는 기화기에서 어떠한 분해 없이 증착 온도에서 안정해야한다.Chemical vapor deposition (CVD) of copper requires the use of stable, volatile precursors. For the purpose of commercialization, the cost of copper precursors is a problem. In addition, the copper precursor provides excellent adhesion, low resistance (~ 1.8 to substrates coated with metal nitrides).

), It must have excellent suitability for surface structure and good electromigration resistance. In CVD processes, which are generally carried out at high temperatures, the copper precursor must have sufficient vapor pressure to achieve a reasonable deposition rate and must also be stable at the deposition temperature without any decomposition in the CVD liquid delivery line or vaporizer.

Copper metal thin films can be prepared by chemical vapor deposition using various copper precursors. In 1990, co-authors such as DB Beach and Chem. Mater. (2) A pure copper film was obtained by CVD using (η ⁵ -C ₅ H ₅ ) Cu (PMe ₃ ) in a paper entitled 'Low Temperature Chemical Vapor Deposition of High Purity Copper from Organic Metal Sources' of 216 (1990). At the same time, collaborators such as Hampden-Smith, MJ, et al. Mater. (2) 636 (1990) published the same result using (t-BuO) Cu (PMe ₃ ). However, these copper films contain carbon and phosphorus, and these elements constitute contaminants when used for wiring in integrated circuits, and therefore they cannot be used for wiring in microprocesses. The study of copper precursors carried out in the early 1990s focused on the evaluation of a series of copper (I) fluorinated β-diketonate complexes that have proven to be very promising sources for use in chemical vapor deposition of copper metal thin films.

Copper (I) fluorinated β-diketonate complexes are described in U.S. Patent No. 4,385,005, entitled "Methods for Separation of Unsaturated Hydrocarbons Using Fluorinated Diketonates and Copper or Silver Complexes", issued May 24, 1983 Was synthesized by Gerald Doyle, as described in U.S. Patent No. 4,425,281, entitled 'Copper or Silver Complexes with Fluorinated Diketones and Unsaturated Ligands', issued January 10, 1984, for its application in the separation of hydrocarbons. .

을 가지고 있으며, 낮은 증착속도를 가지고 있었고, (HYN)Cu(hfac)를 사용한 경우, 구리막은 TiN 기판에 대해 열악한 접착력과 높은 저항성, 즉 ~ 2.1

을 가지고 있다.US Patent No. 5,096,737, entitled 'Liquid Stabilization +1 Metal Beta-diketonate Coordination Complexes and Their Use in Chemical Vapor Deposition of Metal Thin Films,' by co-inventors, issued March 17, 1992, discloses CVD copper thin films. The application of copper (I) fluorinated β-diketonate complexes as copper precursors for the preparation is described. Copper thin films were prepared by chemical vapor deposition using these precursors. Among various liquid copper precursors, 1,6-dimethyl 1,5-cyclooctadiene copper (I) hexafluoroacetylacetonate ((DMCOD) Cu (hfac)) and hexyne copper (I) hexafluoroacetyl 1,5-dimethyl 1,5-cyclooctadiene copper (I) hexafluoroacetylacetonate mixed with acetonate ((HYN) Cu (hfac)) was evaluated in detail. Copper thin films deposited using (DMCOD) Cu (hfac) showed very good adhesion to metal or metal nitride substrates, but high resistance, ie ~ 2.5

In case of having a low deposition rate and using (HYN) Cu (hfac), the copper film has poor adhesion and high resistance to TiN substrate, ie ~ 2.1.

Have

)의 구리막을 형성하지만, 빈약한 접착력을 가지고 있고, 상대적으로 고가이며, 화합물이 고체이기 때문에 CVD에 앞서 기화되어야한다.Another compound, 2-butyne copper (I) (hfac), i.e. ((BUY) Cu (hfac), has low resistance, (~ 1.93

Copper film, but has poor adhesion, is relatively expensive, and the compound is solid and must be vaporized prior to CVD.

A series of trialkylvinylsilanes (TMVS) and stabilized copper (IVS) disclosed in U.S. Patent No. 5,085,731, issued February 4, 1992, as 'Volatile Liquid Precursors for Chemical Vapor Deposition of Copper' by co- inventors Norman et al. The formation of hfac provides an improved copper thin film. Copper films deposited using (hfac) Cu (TMVS) liquid copper precursors have low resistance and reasonable adhesion to the substrate. These liquid copper precursors have been used in the production of copper metal thin films by CVD for a period of time, but still have some drawbacks: stability, poor adhesion to copper films, and the cost of trimethylvinylsilane stabilizers There are significant obstacles to the widespread use of technology.

Other references to note are:

Gerald Doyle, K.A. Eriksen and D. Van Engen, Organometallics 4, 830 (1985; Thomas H. Baum and Carl E. Larson, Chem. Mater. 4, 365 (1992); and Thomas H. Baum and Carl E. Larson, J. Electrochem. Soc. 140 (1), 154 (1993).

A method of forming a volatile copper precursor for chemical vapor deposition of a copper metal thin film is (nRm-cyclohexene) Cu (I) (hfac) (wherein m, m = 1-6) or (nRm-cyclopentene) Cu ( I) formation of volatile liquids having the formula of (hfac) (where nm = 1-5), wherein R is alkyl such as methyl and ethyl.

It is an object of the present invention to provide a series of novel liquid copper precursors with high volatility for chemical vapor deposition of copper metal thin films.

Another object of the present invention is to provide such precursors in economical and stable form.

These and other objects and advantages of the present invention will become more apparent in accordance with the following description described with reference to the drawings.

1 depicts the structure of (n-R-m-cyclohexene) Cu (I) (hfac).

2 depicts the structure of (n-R-m-cyclopentene) Cu (I) (hfac).

3 depicts the structure of (1-methyl-1-cyclohexene) Cu (I) (hfac).

Best Mode for Carrying Out the Invention

The present invention includes chemical vapor deposition (CVD) synthesis of a series of volatile copper precursors to form a copper metal thin film and the synthesis of these precursors. Copper films deposited using these new liquid copper precursors show excellent electrical properties and good adhesion to metal and metal nitride substrates such as W, Ti, TiN, Ta, TaN, Al, Pt and the like.

To achieve this object of the invention, the precursor is

a. It must be a high volatility liquid phase and have a high copper deposition rate to form a copper thin film,

b. Should be stable at room temperature for easy storage and handling,

c. Must have reasonable synthesis cost for commercialization

The copper film produced by CVD using this novel copper precursor was

a. Must have good adhesion to metal and metal nitride substrates such as TiN, WN, TaN, etc.

을 가지고 있어야하고,b. Low resistance, i.e. <1.9

Must have, and

c. Have high electron transfer resistance,

d. It must have excellent suitability for extreme surface morphology.

The present invention described herein is a novel high volatility liquid metal foil copper known as (1-methyl-1-cyclohexene) -copper (I) hexafluoroacetyl acetonate, or (1M1CH) Cu (I) (hfac). Production of precursors. The price of 1-methyl-1-cyclohexene is about $ 120.00 for 100 g, which is very low compared to the price of trimethylvinylsilane used in the prior art is typically $ 180.00 for 100 g. Experimental use of such precursors in CVD tests has demonstrated that these novel high volatility liquid copper foil metal precursors have the desired properties and meet all of the requirements described above.

Copper films deposited using these new liquid copper precursors show excellent electrical properties and good adhesion to metal and metal nitride substrates such as W, Ti, TiN, Ta, TaN, Al, Pt, and the like. These organometallic copper complexes include (nRm-cyclohexene) Cu (I) (hfac) (wherein n, m = 1-6) or (nRm-cyclopentene) Cu (I) shown in FIG. It is represented by the structural formula of (hfac) (where n, m = 1-5), wherein R is alkyl such as methyl and ethyl. Preferably, R is CH ₃ , and as shown in FIG. 3, a (1-methyl-1-cyclohexene) Cu (I) (hfac) compound is formed.

All steps in the synthesis were carried out in a dry glovebox without air or using standard Schlenk technology. The solvent was purified prior to synthesis. Dichloromethane was refluxed before use and distilled over calcium hydride under nitrogen atmosphere. In a preferred embodiment 1-methyl-1-cyclohexene and 1,1,1,5,5,5-hexafluoroacetylacetone were supplied from Aldrich and Strem, respectively, and used as received without further purification.

The synthesis of organometallic copper (I) complexes is described in US Pat. No. 4,385,005, wherein copper monoxide is substituted with unsaturated organohydrocarbons in dichloromethane or THF and 1,1,1,5,5,5-hexafluoroacetyl. Reacted with acetone.

This reaction is described by the following formula.

Where L is an unsaturated organic hydrocarbon ligand.

According to the above described synthesis procedure, the synthesis of (1M1CH) Cu (I) (hfac) provided the desired product, but unfortunately it was unstable for a long time at room temperature. To solve this stability problem, about 5% 1-methyl-1-cyclohexene (by product weight) was introduced into the product for stabilization. Following this procedure, after leaving the compound for one month, no solid precipitate was observed.

In the synthesis of (1M1CH) Cu (I) (hfac), 41.26 g (0.29 mol) of Cu ₂ O was added to a 500 ml round bottom flask with 200 mL of CH ₂ Cl ₂ . The flask is equipped with a stirring bar. To this Cu ₂ O dichloromethane red solution, 57 ml (0.48 mol) of 1-methyl-1-cyclohexene were added. The solution was stirred at room temperature for about 5 minutes, and 100 g (0.48 mol) of 1,1,1,5,5,5-hexafluoroacetylacetone were introduced while stirring. After one minute, the color of the solution slowly changed to green. This green solution was stirred for 10 minutes more continuously and filtered through celite having a filter pore size between about 10 μm and 25 μm.

This green filtrate was stripped under vacuum for 2 hours and then heated to 35 ° C. and further stripped under vacuum for 30 minutes.

A green liquid organometallic copper compound containing a small amount of small green crystals was obtained, which was filtered through a fine filter (1 μm) to give 145.7 g of product having a yield of 82.64 percent on a hfac basis. Theoretical yield was 176.3 g on H (hfac) basis. For stabilization, 1-methyl-1-cyclohexene (6.437 g) was introduced into this product (138.621), which contained 4.44% of free 1-methyl-1-cyclohexene.

NMR structural analysis was performed on a QE 300 MHz NMR instrument, and the results are as follows.

¹ H NMR (C ₆ D ₆ ) (1.22 (multi, 2, C ₆ H ₇ H ₂ CH ₃ ),

1.30 (multi, 2, C ₆ H ₇ H ₂ (CH ₃ )), 1.41 (s, 3, C ₆ H ₇ H ₂ (CH ₃ )),

1.75 (multi, 2, C ₆ H ₇ H ₂ (CH ₃ ))

1.80 (multi, 2, C ₆ H ₇ H ₂ (CH ₃ ))

4.79 (multi, 1, C ₆ H ₈ H (CH ₃ )), 6.15 (s, 1, CF ₃ C (O) CHC (O) CF ₃ )

)을 가지고 있으며, 아주 우수한 재현성을 보여준다. 이러한 전구체는 고휘발성이며, 아주 높은 증착속도, 즉 50℃의 초저온 기화기 온도에서 0.1 ml/분 액체 주입속도를 사용하여 분당 약 500 Å가 달성되었다.The results of copper metal thin films by CVD using (1M1CH) Cu (hfac) liquid precursors were very good. Copper thin films have excellent adhesion and low resistance to metal and metal nitride substrates (~ 1.8

), And has very good reproducibility. This precursor is highly volatile and about 500 kW per minute was achieved using a very high deposition rate, i.e., 0.1 ml / min liquid injection rate, at a cryogenic vaporizer temperature of 50 ° C.

Thus, a new synthetic method was used for the synthesis of (1-methyl-1-cyclohexene) copper (I) (hexafluoroacetylacetonate). (1-methyl-1-cyclohexene) copper (I) (hexafluoroacetylacetonate) is a new liquid copper precursor which is stable at room temperature by adding about 5% of 1-methyl-1-cyclohexene as stabilizer And was highly volatile. Copper films prepared by chemical vapor deposition of (1-methyl-1-cyclohexene) copper (I) (hexafluoroacetylacetonate) have very good adhesion and low resistance to metals and metal nitrides. Copper films prepared by chemical vapor deposition using (1-methyl-1-cyclohexene) copper (I) (hexafluoroacetylacetonate) are useful for IC devices and are very functional.

While preferred embodiments of the invention and various variations thereof have been disclosed, it will be apparent that further modifications and changes may be made thereto without departing from the scope of the invention as defined in the appended claims.

Claims (9)

A method of forming a volatile liquid copper precursor for chemical vapor deposition of a copper metal thin film comprising: Placing 200 ml of CH ₂ Cl _{2 in a} vessel; Cu ₂ O was added to about 41.26 g (0.29 mol) and Cu ₂ O to form a red solution of dichloromethane; Adding 57 ml (0.48 mol) of 1-methyl-1-cyclohexene; Stirring the solution at room temperature for about 5 minutes; adding about 0.48 mole of β-diketone; Stirring for about 11 minutes; Purifying the solution through celite having a filter pore size of about 10 μm to 25 μm; Stripping the solution under vacuum for about 2 hours; Heating the solution to about 35 ° C. under vacuum and stripping for about 30 minutes; Filtering the solution through a fine filter having a pore size of about 1 μm; And adding about 5-10% by weight of 1-methyl-1-cyclohexene for stabilization. The method of claim 1, wherein adding about 0.48 mole of β-diketone comprises adding about 100 g of 1,1,1,5,5,5-hexafluoroacetylacetone. The 1-methyl-1-cyclohexene for stabilization according to claim 1 or 2, so that a copper precursor having a chemical formula of (1-methyl-1-cyclohexene) Cu (I) (hfac) can be prepared. And about 6.437 g of addition. (nRm-cyclohexene) Cu (I) (hfac) (wherein n, m = 1-6) and (nRm-cyclopentene) Cu (I) (hfac) where n, m = 1-5 Volatile copper for chemical vapor deposition of a copper metal thin film comprising forming a volatile liquid having a formula selected from the group of formulas wherein R is alkyl and is selected from the group of alkyls consisting of methyl and ethyl Method of forming the precursor. The method of claim 4 comprising the addition of 1-methyl-1-cyclohexene for stabilization. delete  6. The method of claim 5, wherein the addition of 1-methyl-1-cyclohexene comprises adding about 5-10 wt% of 1-methyl-1-cyclohexene. The method of claim 4 further comprising the addition of β-diketone. The method of claim 8, wherein the addition of β-diketone comprises the addition of 1,1,1,5,5,5-hexafluoroacetylacetone.

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