Polishing solution based on metal Co for polishing process

A polishing liquid and process technology, applied in the field of microelectronics technology, can solve the problems of cobalt copper desorption, fast polishing rate, copper butterfly pit, etc.

Inactive Publication Date: 2012-01-04
FUDAN UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

However, experiments have found that in the presence of oxidants (H 2 o 2 ) in the acidic solution, both copper and cobalt are very soluble, which makes the polishing rate of copper and cobalt too fast during the polishing process, which easily leads to the appearance of dishing of copper
The dissolution of cobalt can easily lead to the dissolution of cobalt in the trench and lead to the desorption of copper.

Method used

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  • Polishing solution based on metal Co for polishing process
  • Polishing solution based on metal Co for polishing process
  • Polishing solution based on metal Co for polishing process

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0016] Polishing solution configuration: 5wt% silica sol; 0.5wt% hydrogen peroxide; 0.75wt% glycine (100 millimolar concentration); 0.06%-0.24wt% dimercaptothiazoline (5mM-20mM concentration); water. Adjust the pH value to 4.0;

[0017] Polishing equipment and mechanical parameter setting: The polishing machine used in this embodiment is the CP-4 table-top polishing machine produced by CETR Company; The rotational speed of the polishing table was 125 rpm.

[0018] The following is the comparison data of cobalt polishing rate with polishing fluid containing different dimercaptothiazoline concentrations.

[0019] Table 1: Polishing rate of cobalt in polishing liquid with different dimercaptothiazoline concentrations

[0020] Concentration of dimercaptothiazoline 0mM 5mM 10mM 15mM 20mM Cobalt polishing rate (nm / min) 905 153 122 119 87

[0021] It can be seen from the data in Table 1 that adding dimercaptothiazoline to the polishing solution c...

Embodiment 2

[0023] Polishing liquid configuration: 5wt% silica sol; 0.5wt% hydrogen peroxide; 0.75wt% glycine (100mM concentration); 0.18wt% dimercaptothiazoline (15mM concentration); and the balance of water. Adjust the pH value to 3.0, 4.0, 5.0 respectively;

[0024] Polishing equipment and mechanical parameter setting: The polishing machine used in this embodiment is the CP-4 table-top polishing machine produced by CETR Company; The rotational speed of the polishing table was 125 rpm.

[0025] Table 2: Under different pH values, the polishing rate and selectivity ratio of copper and cobalt in the polishing solution containing and not containing dimercaptothiazoline

[0026]

[0027] From the data in Table 2, it can be clearly seen that after the addition of dimercaptothiazoline, the polishing rates of cobalt and copper decreased at various pH values. It shows that dimercaptothiazoline has inhibitory effect on cobalt and copper in the whole range of pH value 3-5. At PH value = 5, ...

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Abstract

The invention belongs to the technical field of microelectronic process, in particular to a polishing solution based on metal Co for a polishing process. The polishing agent comprises 0-5% of oxidizing agent, 0.1-25% of grinding particles, 0.001-10% of chelating agent, 0.01-10% of inhibitor and the balance of water according to proportions. The inhibitor is 2-mercaptothiazoline, 2-mercaptobenzothiaozole or other thiazole derivatives or a mixture of several of the 2-mercaptothiazoline, 2-mercaptobenzothiaozole or other thiazole derivatives. The range of the pH value of the polishing solution is 3-5. The inhibitor used for the polishing liquid of the invention can effectively inhibit the static corrosion of copper and cobalt and reduce the polishing rate of copper and cobalt, thereby effectively reducing the defects generated after polishing.

Description

technical field [0001] The invention belongs to the technical field of microelectronic technology, and in particular relates to a polishing liquid used in the microelectronic polishing technology. Background technique [0002] As ultra-large-scale integration (ULSI) technology has evolved to smaller device sizes, the size of the back-end copper interconnects has also shrunk. In order to reduce the interconnection delay, the barrier layer and adhesion layer in the copper interconnection structure are getting thinner and thinner. The traditional copper adhesion layer / barrier layer-Ta / TaN can no longer meet the requirements because of the relatively high resistivity of Ta , and Ta cannot be used as a seed layer for direct copper plating. Metal cobalt (Co) is relatively cheap and has good adhesion to copper. Cu is easy to nucleate on Co, and Co has low resistivity. It can also be used as a direct electroplating seed layer for copper. Cobalt or cobalt alloys have been experimen...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C09G1/02C23F3/06
CPCC23F3/06C23F1/28H01L21/3212C09G1/02C09K3/14
Inventor 鲁海生屈新萍王敬轩
Owner FUDAN UNIV
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