TWI463009B - Composition for post chemical-mechanical polishing cleaning - Google Patents

Description

Composition for chemical mechanical polishing after cleaning

This invention relates to a composition for post CMP cleaning (PCC) of integrated circuits.

Today's semiconductor components are moving toward a small line width and a high bulk density. As the number of stacked layers of the integrated circuit increases and the line width decreases, the time delay (RC-delay) caused by the resistance of the metal wire itself and the parasitic capacitance of the dielectric layer become increasingly important. In order to reduce the problem of RC-delay and increase the signal transmission speed, the copper metallization (copper wire) process has gradually replaced the traditional aluminum metallization (aluminum wire) process to reduce the resistance of the metal line itself. Therefore, the development of copper chemical mechanical polishing (Cu CMP) has become one of the most important technologies in the advanced sub-micron semiconductor process using copper processes. In the current advanced semiconductor manufacturing process, the copper wire layer has reached ten layers and is expected to continue to increase in the future. This also means that several chemical mechanical polishing and chemical mechanical polishing cleaning steps have been included in the entire manufacturing process and may increase in the future.

In the copper chemical mechanical polishing process, the wafer is contaminated with copper ions, chemical mechanical polishing slurry particles, and copper and cerium oxide residues remaining on the wafer surface (including the copper layer and the dielectric layer). Therefore, usually after the chemical mechanical polishing step, a cleaning step is required to remove the above contaminants.

Basically, chemical mechanical polishing is the final step in the chemical mechanical polishing process. The goal is to provide a clean wafer surface for subsequent processing.

In order to reduce the loss of yield, the following points should be noted when cleaning after chemical mechanical polishing and chemical mechanical polishing:

(1) Effective removal of the azole corrosion inhibitor,

(2) need to effectively control the accumulation of process stress,

(3) It is necessary to select a suitable low-k material to meet the requirements of chemical mechanical polishing and post-cleaning, and

(4) Need to avoid scratching problems.

There are a number of documents in the prior art that provide compositions for chemical mechanical polishing after the cleaning process. For example, US Patent No. 6,541,434 to Wang discloses a cleaning composition comprising a carboxylic acid, an amine-containing compound, a phosphonic acid, and water, which is suitable for removing abrasives and metal contamination remaining after chemical mechanical polishing. U.S. Patent No. 6,627,546 to Kneer discloses a non-fluorinated aqueous composition comprising a dicarboxylic acid and/or a salt thereof, a hydroxycarboxylic acid and/or a salt thereof or an acid containing an amine group. U.S. Patent Publication No. US 2005/0014667 to Aoyama et al. discloses a fluorochemical (surfactant), water, guanamine and ether solvent and is selected from the group consisting of amino sulfonic acids, phosphonic acids, soluble phosphonic acid derivatives or A combined aqueous acid detergent for its combination. No. 7,297,670 to Misra et al. discloses a composition comprising a cleaning agent, a corrosion inhibitor, and mercaptopropionic. US Patent Publication No. US 2004/0204329 to Abe et al. discloses a cleansing liquid composition comprising a liquid cleaning composition of a particular etheric organic solvent and having better wettability for a hydrophobic substrate. No. 7,208,409 to Zhang et al. discloses a solution for chemical mechanical polishing post-treatment comprising a nonionic acetylene glycol derivative surfactant.

Since the contaminant removal rate of the cleaning solution after chemical mechanical polishing is directly related to its pH and zeta potential, generally a lower boundary potential provides a better contaminant removal rate. In addition, since alkaline compositions generally have a lower boundary potential, they are more suitable as a chemical mechanical polishing post-cleaning composition.

In addition, in addition to the contaminant removal rate considerations, good chemical mechanical polishing after cleaning fluids also need to have the following characteristics:

(1) The cleaning liquid does not attack or etch metal, and includes a copper layer as a metal connection or a metal nitride as a barrier layer, such as TaN or TiN,

(2) The cleaning solution does not attack or etch the dielectric layer, including yttrium oxide, high density low-k materials, or porous low-k materials.

Therefore, although many prior art techniques have provided various chemical mechanical polishing cleaning fluids, the industry still needs to be more effective in removing contaminants remaining on the wafer surface, reducing wafer surface defects and not destroying or etching the substrate. The composition is then cleaned after the material structure.

It is an object of the present invention to provide a cleaning composition suitable for use after chemical mechanical polishing comprising at least one water soluble amine, at least one water soluble organic solvent and deionized water. By contacting the composition of the present invention with the copper-containing semiconductor wafer for an effective period of time, the contaminants remaining on the surface of the wafer after polishing can be effectively removed and the number of defects on the surface of the wafer can be reduced.

Another object of the present invention is to provide a chemical mechanical polishing cleaning method which is followed by chemical mechanical polishing to contact a wafer with a composition comprising at least one water-soluble amine, at least one water-soluble organic solvent and deionized water. Effective time to remove residual contaminants after chemical mechanical polishing from the wafer.

The composition of the present invention suitable for post-chemical mechanical polishing cleaning comprises at least one water soluble amine, at least one water soluble organic solvent and deionized water.

The cleaning compositions of the present invention remove contaminants, particularly azole corrosion inhibitors, from the wafer surface by redox reactions of water soluble amines and contaminants contained therein. Commonly used in the inhibition of azole corrosion are triazole corrosion inhibitors such as benzotriazole (BTA) and 1,2,4-triazole.

The water-soluble amines in the cleaning compositions of the present invention may be diazo or azo compounds such as hydrazine, hydrazine hydrate, hydrazoic acid or sodium azide.

In one embodiment of the invention, the water soluble amines in the cleaning composition are selected from the group consisting of hydrazines, hydrazine hydrates, or combinations thereof. In a preferred embodiment of the invention, the water soluble amine in the cleaning composition is a hydrazine.

The water soluble amines may comprise from about 1 to about 30% by weight, preferably from about 1 to about 25% by weight, more preferably from about 1 to about 10% by weight of the total weight of the composition of the cleaning composition of the present invention. %.

The cleaning composition of the present invention comprises a water-soluble organic solvent which reduces the surface tension of the cleaning composition and increases the wettability of the surface of the wafer.

The water-soluble organic solvent in the cleaning composition of the present invention may be an organic ether, an organic alcohol, an organic ketone or an organic decylamine, preferably selected from the group consisting of dimethyl hydrazine (DMSO), a diol compound, and N- Methylpyrrolidone (NMP), dimethylacetamide (DMAC), dimethylformamide (DMF) or a mixture thereof. The diol compound is preferably diethylene glycol monobutyl ether (BDG), ethylene glycol monoethyl ether, ethylene glycol dimethyl ether, ethylene glycol n-butyl ether, ethylene glycol monobutyl ether acetic acid or a mixture thereof.

The water-soluble organic solvent may comprise from about 10 to about 59 weight percent, preferably from about 10 to about 50 weight percent, more preferably from about 10 to about 25 weight percent, based on the total weight of the composition, of the cleaning composition of the present invention. %.

The cleaning composition of the present invention comprises deionized water in an amount of from about 30 to about 89% by weight, preferably from about 50 to about 85% by weight, more preferably from about 65 to about 8% by weight based on the total weight of the composition. 85 wt%.

The chemical mechanical polishing cleaning method of the present invention can be carried out on any conventionally applicable cleaning machine, and the machine can be the same machine or a different machine than the machine used in the chemical mechanical polishing process, and the method includes The chemical mechanical polishing wafer is contacted with a composition comprising at least one water soluble amine, at least one water soluble organic solvent and deionized water on a cleaning machine for an effective period of time to remove residual contaminants from the wafer.

Example

The invention is further described in the following examples, which are not intended to limit the scope of the invention, and are intended to be included within the scope of the invention.

Example 1

The cleaning composition of the present invention (Composition C) was prepared with 7 wt% of hydrazine, 20 wt% of BDG, and 73 wt% of deionized water. The surface tension of the composition C was determined to be 30.46 mN/m. A commercially available citric acid as a main component of the washing solution was also used as a control group. The chemically and mechanically polished copper test wafer and blank wafer were cleaned using Composition A and Composition C on a Mesa machine of Applied Materials, Inc., respectively, for 20 seconds, and the cleaning agent flow rate was 2000 per minute. ML. The commercially available citric acid as a main component of the cleaning solution was tested under the same cleaning conditions, and the surface tension was 72 mN/m (control group, cleaning composition A).

After cleaning, the number of defects on the surface of the test wafer was observed by KLA-Tencor surfscan AIT. The results are as follows:

The results show that the cleaning effect of the cleaning composition C of the present invention is better than that of the cleaning composition A. The results of cleaning the copper wafer and the blank wafer using the cleaning composition C showed that the total number of defects was less than that of the cleaning composition A. In addition, the copper test wafer and the blank wafer after the composition C cleaning were measured by Candela CS10, and the results showed that the thickness of the wafer surface layer before and after the cleaning was constant, that is, the composition C of the present invention did not etch the surface of the wafer.

Examples 2 and 3

The cleaning composition of the present invention was formulated and tested in a manner similar to that of Example 1 as follows:

According to the test results, it was found that the above composition was better in cleaning effect than the commercially available cleaning composition. Since the cleaning composition of the present invention has a small surface tension, the wettability of the wafer surface can be increased, so that a good cleaning effect is obtained.

Claims (10)

A composition for chemical mechanical polishing after cleaning comprising from about 1 to about 30% by weight, based on the total weight of the composition, of a water-soluble amine, from about 10 to about 50% by weight of a water-soluble organic solvent, and from about 50 to About 89% by weight of deionized water. The composition of claim 1, wherein the water soluble amine is selected from the group consisting of a hydrazine, a hydrazine hydrate, or a combination thereof. The composition of claim 1, wherein the water-soluble organic solvent is selected from the group consisting of dimethyl hydrazine (DMSO), a diol compound, N-methylpyrrolidone (NMP), dimethylacetamide (DMAC), and Methylformamide (DMF) or a mixture thereof. The composition of claim 3, wherein the diol compound is selected from the group consisting of diethylene glycol monobutyl ether (BDG), ethylene glycol monoethyl ether, ethylene glycol dimethyl ether, ethylene glycol n-butyl ether, ethylene glycol single Butyl ether acetic acid or a mixture thereof. The composition of claim 1 wherein the water soluble amine is from about 1 to about 25 weight percent. The composition of claim 5, wherein the water soluble amine is from about 1 to about 10% by weight. The composition of claim 1 wherein the water soluble organic solvent comprises from about 10 to about 25 weight percent. The composition of claim 1 wherein the deionized water system comprises from about 50 to about 85% by weight. The composition of claim 8 wherein the deionized water system comprises from about 65 to about 85% by weight. A chemical mechanical polishing post-cleaning method comprising the step of contacting a chemically mechanically polished wafer with a composition of any one of claims 1 to 9 for an effective period of time to remove residual contaminants from the wafer.