WO2007048315A1

WO2007048315A1 - A chemical mechanical polishing paste for tantalum barrier layer

Info

Publication number: WO2007048315A1
Application number: PCT/CN2006/002619
Authority: WO
Inventors: Judy Jianfen Jing; Peter Weihong Song; Yuan Gu; Sunny Chun Xu; Michael Ying Song
Original assignee: Anji Microelectronics (Shanghai) Co., Ltd
Priority date: 2005-10-28
Filing date: 2006-10-08
Publication date: 2007-05-03
Also published as: CN1955248A; CN1955248B

Abstract

A chemical mechanical polishing paste for tantalum barrier layer is disclosed, which comprises abrasive particles, organic phosphonic acid, tetrazoles compounds and carrier. The present chemical mechanical polishing paste can prevent local and general corrosion of metal material, reduce contaminant on substrate surface, save abrasive particles, so as to achieve the appropriate polishing selectivity between different metals and oxides.

Description

Chemical mechanical 3⁄4t optical paste for 钽 barrier layer

The present invention relates to a chemical mechanical polishing slurry, and more particularly to a chemical mechanical polishing slurry for a barrier layer. technical background

With the development of microelectronics technology, the integration of very large-scale integrated circuit chips has reached several billion components, and the feature size has entered the nanometer level, which requires hundreds of processes in the microelectronics process, especially multilayer wiring. The substrate and the medium must be chemically mechanically planarized. Very large scale integrated wiring is being converted from traditional A1 to Cu. Compared with A1, Cu wiring has the advantages of low resistivity, high electromigration resistance, and short RC delay time, which can reduce the number of layers by half, reduce the cost by 30%, and shorten the processing time by 40%. The advantages of Cu wiring have attracted widespread attention around the world.

In order to ensure the characteristics of the Cu wiring and the dielectric, the multilayer copper wiring in the current large scale integrated circuit chip also uses Ta or TaN as a barrier layer, so that chemical mechanical polishing (CMP) slurry for polishing the Ta or TaN barrier layer has appeared one after another. For example, US Pat. No. 6,719,920 discloses a polishing slurry for a barrier layer; US Pat. No. 6,503,418 discloses a polishing slurry of a Ta barrier layer containing an organic additive; US 6,638,326 A chemical mechanical planarization composition for Ta and TaN, CN 02116761.3 discloses a chemical mechanical global planarization polishing solution of copper and tantalum in a multi-scale integrated circuit multilayer copper wiring. However, these polishing slurries have local and overall corrosion, high defect rate, and unreasonable polishing selectivity of different substrates. Therefore, there is an urgent need to develop a new chemical mechanical polishing slurry for a barrier layer. Summary of invention

SUMMARY OF THE INVENTION An object of the present invention is to provide a chemical mechanical polishing slurry for a barrier layer in order to solve the above problems in the prior art.

The above object of the present invention is achieved by the following technical solutions: The chemical mechanical polishing slurry for the ruthenium barrier layer of the present invention comprises abrasive particles, an organic phosphonic acid, a tetrazolium compound and a carrier. Since the chemical mechanical polishing slurry of the present invention incorporates an organic phosphonic acid and a tetrazolium compound, it has suitable polishing selectivity for different metals and oxides during polishing, can prevent metal depression, and significantly reduce the wafer surface. Organic matter, deposition of silicon dioxide and residues of other metal ions.

The components of the chemical mechanical polishing slurry for the ruthenium barrier layer of the present invention can be referred to the prior art. In a preferred embodiment of the present invention, the concentration of the abrasive particles is 1 to 10%, and the organic phosphonic acid The concentration is 0.01 to 1%, the concentration of the tetrazole compound is 0.01 to 0.5%, and the carrier is the balance, and the above % means the total weight percentage of the entire chemical mechanical polishing slurry.

In the present invention, the size of the abrasive particles is preferably from 20 to 200 nm, more preferably from 30 to 100 nm, most preferably 70 nm.

The organic phosphonic acid is preferably 2-phosphonic acid butane-1,2,4-tricarboxylic acid (PBTCA), ethylenediaminetetramethylenephosphonic acid and/or diethylenetriamine pentamethylphosphine. acid.

The tetrazole compound (TRA) is preferably ?-methyl-tetrazole, 5-phenyl-1-hydro-tetrazole and/or 1-hydro-tetrazolium.

The chemical mechanical polishing slurry for the ruthenium barrier layer of the present invention may further comprise 0.001 to 1% of an oxidizing agent. The oxidizing agent may be various oxidizing agents in the prior art, preferably hydrogen peroxide, urea hydrogen peroxide, peroxyacetic acid, benzoyl peroxide, potassium persulfate and/or ammonium persulfate, more preferably The ground is hydrogen peroxide.

The abrasive particles of the present invention may also be referred to the prior art, preferably silica, alumina, yttria and/or polymer particles such as polyethylene or polytetrafluoroethylene, more preferably silica.

The chemical mechanical polishing slurry for the ruthenium barrier layer of the present invention preferably has a pH of 2.0 to 4.0, more Preferably, the pH adjusting agent may be various acids and/or bases to adjust the pH to a desired value, preferably potassium hydroxide, nitric acid, ethanolamine and/or triethanolamine or the like.

The chemical mechanical polishing slurry for the barrier layer of the present invention may further comprise a surfactant, a stabilizer, an inhibitor and/or a bactericide to further improve the polishing performance of the surface of the substrate.

In the present invention, the carrier is preferably water.

The chemical mechanical polishing slurry for the barrier layer of the present invention may further include other additives such as a surfactant, a bactericide, a stabilizer, and/or a suppressing agent, etc., and these additives may be referred to the prior art.

The positive progressive effect of the present invention is that the chemical mechanical polishing slurry 1) of the ruthenium barrier layer of the present invention can reduce the amount of abrasive particles, and significantly reduce defects, scratches, stains and other residues, thereby reducing surface contamination of the substrate. 2) Appropriate polishing selection ratio during polishing; It can prevent local and overall corrosion generated during metal polishing and improve product yield.

DRAWINGS

Figure 1 is a 3⁄4 surface micrograph of a blank germanium wafer before polishing;

Figure 1 is a surface micrograph of a blank germanium wafer after polishing;

Figure 3 is a micrograph of the surface of the test wafer after polishing (magnification 250 times) (TEOS refers to Si0 _{2 in the} figure); Figure 4 is an SEM image of the surface of the test wafer after polishing (magnification 5,000 times) (TEOS refers to Si0 _{2 in the} figure).

SUMMARY OF THE INVENTION The invention is described in detail below using non-limiting examples. Examples 1 to 8 and Comparative Example 1 ^G Table 1

Remarks: TRAl: 5-methyl-tetrazole; TRA2: 1-hydro-tetrazole; TRA3: 5-phenylhydrogen-tetrazole; EDTMP: ethylenediaminetetramethylenephosphonic acid; DTPMP: Ethylene triamine pentamethylphosphonic acid; the remaining component of the above chemical mechanical polishing slurry is water; 1 ^Q is Comparative Example 1 ^G .

The materials are added to the reactor in the following order: grinding granules, half of the amount of deionized water, organic phosphonic acid, TRA, H ₂ 0 ₂ and stirring uniformly, adding the remaining deionized water, and finally using the pH adjuster. (20% KOH or dilute HN0 ₃ , selected according to the pH value) Adjust to the desired pH value and continue to stir to a uniform fluid, and obtain a chemical mechanical polishing slurry after standing for 10 minutes.

Effect embodiment 1

The blank Ta, Cu, and Si0 ₂ wafers were polished by the chemical mechanical polishing slurries of the above Examples 1 to 8 and Comparative Example 1 ^G , respectively, and the polishing conditions were the same. The polishing parameters were as follows: Logitech. Polishing pad, downward pressure 2 psi, turntable Speed / polishing head speed -60/80 rpm, polishing time 120s, chemical mechanical polishing slurry flow rate 100mL / min. The polishing results are shown in Table 2. Table 2

Remarks: Surf. indicates the contamination of the substrate surface.

The results show that the chemical mechanical polishing slurry of the present invention can adjust the removal rates of Ta, Cu and Si0 ₂ by adding organic acids and tetrazoles, and adjust the concentration of abrasive particles, organic acids and tetrazoles. A suitable polishing selectivity results in better polishing selectivity when adjusting the oxidant concentration. 1 is a surface micrograph of a blank Ta wafer before polishing of the chemical mechanical polishing slurry of Example 1, and FIG. 2 is a surface micrograph of a blank Ta wafer polished by the chemical mechanical polishing slurry of Example 1, from FIG. It can be seen from 2 and 2 that the defects can be significantly reduced at a lower abrasive particle concentration, and local and overall corrosion generated during metal polishing can be prevented, and surface contamination of the substrate can be reduced, and the chemical mechanical polishing slurry of the present invention can be used. Pitting corrosion on the surface of the Ta wafer after the material can be significantly less, thereby improving product yield. .

Effect Example 2

The silicon substrate wafers which have been sputtered with Ta/electroplated copper are polished and then polished with the chemical mechanical polishing slurry of Examples 2, 3 and 5 respectively. The polishing conditions are the same, and the polishing parameters are as follows: Logitech . Polishing pad, down pressure 2 psi, turntable speed / polishing head speed = 60/80 rpm, polishing time 120 s, chemical mechanical polishing slurry flow rate 100 mL / min. The polishing results are shown in Table 3.

table 3

The results show that after the chemical mechanical polishing slurry of the present invention is used, the size of the surface of the test wafer is significantly reduced, and the surface of the test wafer is free from corrosion, contaminants and other residues. After the chemical mechanical polishing slurry of Example 2 was polished, the surface of the test wafer was magnified by a microscope for 250 times and no contaminant was present (see FIG. 3); ^^ After polishing the chemical mechanical polishing slurry of Example 3, the surface of the test wafer was subjected to SEM. Amplification of 5000 times did not clearly see the presence of pollution, corrosion, etc. (see Figure 4).

Conclusion: The chemical mechanical polishing slurry of the ruthenium barrier layer of the invention can reduce the amount of abrasive particles, and reduce the defects, scratches, stains and other residues, thereby reducing the surface contamination of the substrate; 2) during polishing It has a suitable polishing selection ratio; it can prevent local and overall corrosion generated during metal polishing and improve product yield.

The raw materials involved in the above examples are all commercially available.

Claims

Rights request

A chemical mechanical polishing paddle for a barrier layer comprising abrasive particles, an organic phosphonic acid, a tetrazolium compound and a carrier. .

2. The chemical mechanical polishing slurry according to claim 1, wherein the concentration of the abrasive particles is 1 to 10%, the concentration of the organic phosphonic acid is 0.01 to 1%, and the concentration of the tetrazolium compound. The carrier is 0.01 to 0.5%, and the carrier is the balance.

The chemical mechanical polishing slurry according to claim 1, wherein the abrasive particles have a size of 20 to 200 nm.

A chemical mechanical polishing slurry according to claim 3, wherein the abrasive particles have a size of 30 to 1:100 nm.

The chemical mechanical polishing slurry according to any one of claims 1 to 4, wherein the organic phosphonic acid is butane-1,2,4-tricarboxylic acid 2-phosphonate, Amine tetramethylene phosphonic acid and/or diethylene triamine pentamethylphosphonic acid.

The chemical mechanical polishing slurry according to any one of claims 1 to 4, wherein the tetrazole compound is 5-methyl-tetrazole, 5-phenyl-1-hydrogen- Tetrazolium and/or 1-hydro-tetrazole.

The chemical mechanical polishing slurry according to any one of claims 1 to 4, wherein the chemical mechanical polishing slurry further comprises 0.001 to 1% of an oxidizing agent.

8. The chemical mechanical polishing slurry according to claim 7, wherein the oxidizing agent is hydrogen peroxide, urea hydrogen peroxide, peracetic acid, benzoyl peroxide, potassium persulfate and/or persulfuric acid. Ammonium c

The chemical mechanical polishing slurry according to any one of claims 1 to 4, wherein the abrasive particles are silica, alumina, cerium oxide and/or polymer particles.

The chemical mechanical polishing slurry according to any one of claims 1 to 4, wherein the chemical mechanical polishing slurry has a pH of from 2.0 to 4.0.

The chemical mechanical polishing slurry according to any one of claims 1 to 4, wherein the chemical mechanical polishing slurry further comprises a surfactant, a stabilizer and/or a bactericide.