Slurry for chemical mechanical polishing of cobalt

a technology of mechanical polishing and slurry, which is applied in the field of microelectronics technology, can solve the problems of copper and cobalt easily suffering from dissolution in acidic solution containing oxidants, ta/tan is not suitable anymore, and the cobalt barrier/adhesion layer stack is not suitable anymor

Inactive Publication Date: 2013-06-06
FUDAN UNIV
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  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

The traditional copper barrier/adhesion layer stack—Ta/TaN is not suitable any more, as the resistivity of Ta is relatively high and copper cannot be directly electroplated onto Ta.
It is reported that low k can be easily damaged by plasma or polishing slurries.
But it is observ

Method used

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  • Slurry for chemical mechanical polishing of cobalt
  • Slurry for chemical mechanical polishing of cobalt
  • Slurry for chemical mechanical polishing of cobalt

Examples

Experimental program
Comparison scheme
Effect test

embodiment 1

[0022]The components of slurries: 1 wt % colloidal SiO2; 0.75 wt % glycine; 0.12 wt % 2-mercaptothiazole; and the rest of water. Using the diluted nitric acid and potassium hydroxide to adjust the pH value to 3.

[0023]The polishing equipment and mechanical parameters: the polisher is CP-4 bench top polisher made by CETR Company in this embodiment. The polishing pressure is 2 psi, flow rate is 100 ml / min, and rotation rate is 150 rpm for both of polishing head and platen.

Contrast 1

[0024]The slurries is the same as those in embodiment 1 except without 2-mercaptothiazole; The polishing equipment and mechanical parameters are also the same as those in embodiment 1.

[0025]Table 1 lists the corrosion rate and polishing rate of Co in embodiment 1 and Contrast 1.

TABLE 1corrosion rate and polishing rate of Co in embodiment 1 and contrast 12-mercaptothiazole0 wt % 2-0.12 wt %mercaptothiazole2-mercaptothiazoleCorrosion rate of Co□nm / min□50Polishing rate of Co□nm / min□7327

[0026]Shown in table 1, ...

embodiment 2

[0028]The components of slurries: 5 wt % colloidal SiO2; 0.5 wt % H2O2; 0.75 wt % glycine; 0-0.24 wt % Benzotriazole; and the rest of water. The pH value of the slurry is adjust to 5. The concentrations of Benzotriazole are controlled to 0.06 wt %, 0.12 wt %, 0.18 wt %, 0.24 wt % for all the slurries.

[0029]The polishing equipment and mechanical parameters: the polisher is CP-4 bench top polisher made by CETR Company in this embodiment. The polishing pressure is 2 psi, flow rate is 100 ml / min, and rotation rate is 150 rpm for both of polishing head and platen.

[0030]Table 2 lists the corrosion rate of Co in the slurries with different concentrations of Benzotriazole.

TABLE 2corrosion rate of Co in embodiment 2Concentrations ofBenzotriazole□wt %□00.060.120.180.24Corrosion rate of Co5014962(nm / min)

[0031]From the data in table 2, we can see that the corrosion rate of Co is decreased as the increase of concentration of Benzotriazole. When the concentration of Benzotriazole is up to 0.24 wt...

example 3-8

[0033]The components of the slurries (the rest is water) and the experimental data of embodiments 3-8 are listed in table 3.

TABLE 3components of the slurries and experiment results of embodiments 3-8embodiment 3embodiment 4embodiment 5embodiment 6embodiment 7embodiment 8Inhibitor wt %BenzotriazoleBenzotriazole / Benzotriazole / Benzotriazole / Benzotriazole / imidazo / 0.3 %imidazole2-Aminobenz2-Mercaptob2-MercaptobenBenzotriazole / 1:1)imidazoleenzimidazolezimidaz (1.:1)2-mercaptoth0.7%(1:1)(1:1)1.2%iazole (1:1:1)1%2%1.8%Oxidant wt %H2O2(NH4)2S2O8KIO4KClO4(NH4)2S2O8 / H2O2 / 0.1%  5%1%4%H2O2 (1.:2)KIO4 (3:1)  2%0.6%AbrasiveColloidalColloidalCeO2Al2O3Colloidal SiO2 / Colloidalwt %SiO2SiO23.5%  10% CeO2SiO2 / Al2O3 /   1%0.1%(1.:1)Ce02(3:1:1)  7%5.2%Complexingglycine / citric arginineCitric acidGlutamic acidglycine / glycine / agent wt %acid (1.:1)0.4%2%6%Glutamic acidarginine / 0.1%(3.:1)Citric acid10%(1.:1:4)0.8%pH value3.04.05.04.03.03.0Corrosion1.553552rate of Co□nm / min□Polishingrate 458510022012060of Co□nm / ...

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Abstract

A slurry for chemical mechanical polishing of Co. The slurry comprises components by weight as follows, Inhibitor 0.01-2%, Oxidant 0-5%, Abrasive 0.1-10%, Complexing agent 0.001-10%, and the rest of water. The pH value of the slurries is adjusted to 3-5 by a pH value adjustor. The inhibitor is chosen from one or more kinds of five-membered heterocycle compound containing S and N atoms or containing S or N atom. The oxidant is one or more chosen from H2O2, (NH4)2S2O8, KIO4, and KClO5. The abrasive is one or more chosen from SiO2, CeO2, and Al2O3. The complexing agent is one or more chosen from amino acid and citric acid. The slurry can effectively prevent Co over corrosion and reduce the polishing rate of Co in the polishing process.

Description

TECHNICAL FIELD [0001]The present invention relates to microelectronics technology, especially relates to chemical mechanical polishing (CMP) slurries and related applications.BACKGROUND OF THE INVENTION[0002]With the continuous shrink of feature size in ultra large scale integrated Circuits (ULSI) technology, the size of the copper interconnect structure is getting more and more smaller. To reduce the RC delay, the thickness of barrier or adhesion layer in the copper interconnect structure is getting thinner. The traditional copper barrier / adhesion layer stack—Ta / TaN is not suitable any more, as the resistivity of Ta is relatively high and copper cannot be directly electroplated onto Ta. Compared with Ta, cobalt has lower resistivity and is relatively cheaper. The adhesion between Cu and Co is good. Cu can easily nucleate on Co, also copper can be directly electroplated on cobalt.[0003]Porous low k dielectrics material has been already used in the current interconnect structures. I...

Claims

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Application Information

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IPC IPC(8): C23F1/28
CPCC09G1/02H01L21/3212C23F1/28C09K3/14
Inventor LU, HAISHENGQU, XINPINGWANG, JINGXUAN
Owner FUDAN UNIV
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