KR20130092096A - Chemical mechanical polishing cleaning coposition and the cleaning method therewith - Google Patents

Abstract

PURPOSE: A chemical-mechanical polishing detergent composition, and a cleaning method using the same are provided to remove an organic material pollution layer on the copper surface in a cleaning process after a copper chemical-mechanical polishing process, and to obtain an oxide film which is maintained stably until a subsequent process. CONSTITUTION: A liquid detergent composition comprises: an organic solvent comprising KOH or/and TMAH; a chelate reagent comprising EDTA and/or arginine; an anticorrosive agent; and pure water. To the total amount of the liquid detergent composition, the organic solvent, chelate reagent, and anticorrosive agent are comprised in a ratio of 1-10 wt%, 1-10 wt%, and 0.2-2 wt%respectively. A cleaning method of a copper chemical-mechanical polishing process comprises the steps of: polishing the surface of copper chemical-mechanically; and cleaning the polished copper surface using the liquid detergent composition. [Reference numerals] (AA) Example 2-1

Description

Chemical mechanical polishing (CPM) cleaning composition and cleaning method using the same {CHEMICAL MECHANICAL POLISHING CLEANING COPOSITION AND THE CLEANING METHOD THEREWITH}

The present invention relates to a cleaning liquid and a cleaning method used in a chemical mechanical polishing process, and more particularly, to a cleaning liquid for a copper chemical mechanical polishing post cleaning process used for cleaning after chemical mechanical polishing of copper wiring and a cleaning method using the same. .

As the line width of the wiring gradually decreases in the semiconductor process, the resistance is increased due to the reduction of the cross-sectional area of the wiring, and the signal is delayed due to the reduction of the wiring interval. In order to reduce this signal delay, the material of the wiring is replaced by copper (Cu) with low specific resistivity and the dielectric is replaced by a material with a lower dielectric constant.

However, when a dry etch back process used in a conventional tungsten (W) and aluminum (Al) wiring forming process is applied to a copper wiring forming process, copper reacts with chlorine (Cl) A chlorine complex is formed. The copper-chlorine complex remains on the surface of the substrate and acts as an obstacle that interferes with the etching, thereby causing a problem in forming a pattern.

To overcome this, a chemical mechanical polishing (CMP) process was introduced. That is, a copper wiring is formed on a semiconductor substrate through a damascene process using the chemical mechanical polishing process. In the copper wiring formation process using the chemical mechanical polishing, copper removal is performed in two steps because of oxide settlement and copper settlement due to the difference in removal selectivity between materials.

After the chemical mechanical polishing process, the copper surface is present on the surface with particles and organic additives contained in the slurry. Surface adsorption of the particles in the slurry during the copper chemical mechanical polishing (CMP) process can achieve removal and re-adsorption prevention through the implementation of negative zeta potential by using a basic cleaning composition.

However, it is not easy to remove the unstable copper oxide film formed by the oxidation-corrosion prevention mechanism used in the copper chemical mechanical polishing (CMP) process and the organic material contamination formed thereon. Therefore, in the cleaning process after copper chemical mechanical polishing (CMP), it is required to completely remove the organic contaminant layer, and to protect the copper film through formation of a stable oxide film to a subsequent process.

Conventional lift off cleaning has a problem in protecting the copper film by forming a stable copper oxide film by etching the copper oxide film, thereby completely removing organic contamination after copper chemical mechanical polishing (CMP), and removing the copper film by forming a stable oxide film. There is a need for a cleaning liquid composition that protects subsequent processes without alteration.

The present invention has been invented to solve the above problems, and the organic contaminant layer is completely removed from the cleaning process after the chemical mechanical polishing (CMP) process, particularly the surface cleaning process after the copper chemical mechanical polishing (CMP) process, and then to the subsequent process. The present invention provides a cleaning liquid composition capable of forming a stable oxide film and a cleaning method after a chemical mechanical polishing (CMP) process using the same.

The present invention provides a stable cleaning liquid composition and a chemical mechanical polishing (CMP) process using the same. It is to provide a post-cleaning method.

Cleaning liquid composition according to an aspect of the present invention KOH, TMAH or an organic solvent comprising both; Chelating reagents comprising EDTA, arginine or both; Corrosion inhibitors; And pure water.

The organic solvent may be 1 to 10% by weight in the cleaning liquid composition, the chelating reagent may be 1 to 10% by weight in the cleaning liquid composition, and the corrosion inhibitor may be 0.2 to 2% by weight in the cleaning liquid composition. .

The cleaning liquid composition may have a pH of 10 to 12.5.

The cleaning liquid composition may have a contact angle of 45 or less on the copper surface cleaned with the cleaning liquid composition after a copper chemical mechanical polishing (CMP) process.

The cleaning liquid composition may be used at a dilution ratio of 1:10 to 1: 100 when cleaning the copper surface after the copper chemical mechanical polishing (CMP) process.

In another aspect of the present invention, a copper chemical mechanical polishing (CMP) process cleaning method comprises the steps of: chemical mechanical polishing (CMP) polishing a copper surface; And cleaning the polished copper surface using the cleaning liquid composition of the present invention.

The cleaning liquid composition of the present invention can completely remove the organic contaminant layer on the copper surface in the cleaning process after the copper chemical mechanical polishing (CMP) process, and obtain an oxide film which is stably maintained until the subsequent process.

In addition, even when used as a diluting solution in the cleaning step, the pH of the composition is stably maintained, and the change in the contact angle of the surface before and after cleaning can be minimized.

In addition, since the cleaning liquid composition of the present invention does not cause a surface change such as discolor of the copper surface even in the case of being supported for a long time, process operation such as adjustment of cleaning time is advantageous.

1 is a graph showing the pH change according to the dilution ratio of the cleaning liquid compositions of Examples 1-1, 2-1 and 3-1 and the commercial cleaning agents of Comparative Examples 1 to 3 of the present invention.
2 is a TEM image of a copper surface after performing a cleaning process with the cleaning liquid composition of Example 2-1 of the present invention.
3 is a TEM image of a copper surface after performing a cleaning process with a commercial cleaning solution of Comparative Example.

Cleaning liquid composition according to an aspect of the present invention KOH, TMAH or an organic solvent comprising both; Chelating reagents comprising EDTA, arginine or both; Corrosion inhibitors; And pure water.

The cleaning liquid composition of the present invention contains KOH (potassium hydroxide) or TMAH (Tetramethyl ammounium hydroxide, tetramethyl ammonium hydroxide) as an organic solvent, EDTA (ethylenediamine tetraacetic acid, ethylenediamine tetraacetic acid, Formula: (HOOCCH ₂ ) ₂ NCH ₂ CH ₂ N (CH ₂ COOH) ₂ ) or arginine, including a corrosion inhibitor such as 5-amino-1H-Tetrazole, with respect to the remaining amount Pure water, preferably ultrapure water (DI water).

The organic solvent may be 1 to 10% by weight of the cleaning liquid composition, 4 to 10% by weight may be more preferable, and the chelating reagent may be 1 to 10% by weight of the cleaning liquid composition, 4 to 8% by weight % May be more preferred.

The corrosion inhibitor may be 0.2 to 2% by weight of the cleaning liquid composition.

TMAH (tetramethylammonium hydroxide) used as an organic solvent is used as a cleaning liquid for removing semiconductor PR strippers and the like, and has an excellent cleaning effect. In particular, by implementing a negative zeta potential in the solution with a basic solvent it can prevent the re-adsorption of particles after washing through electrostatic repulsion.

The abrasive particles in the Cu slurry have a negative zeta potential, and using a basic organic solvent containing no metal ions after the CMP process can easily remove the particles and prevent resorption. Since the organic solvent plays a role as a final pH adjuster, its content is determined at a pH level which shows adequate performance.

In the case of a chelating reagent, it acts as a complexing agent for the metal ion that occurs when the cleaning process proceeds. It also has a weak acid to form a buffer solution of basic organic solvent and weak acid-strong base so that the appropriate pH range is maintained regardless of the dilution ratio.

In the case of a corrosion inhibitor, it acts to protect the metal surface during the cleaning action, and may remain on the wafer surface when excessively added, causing organic contamination.

In the cleaning liquid composition of the present invention, the contact angle of the copper surface, which has been subjected to the copper chemical mechanical polishing (CMP) process using the cleaning liquid composition, may be 45 or less.

Increasing the contact angle after the chemical mechanical polishing (CMP) process and cleaning means that the surface has been converted to hydrophobic. Since the contact angle of the surface of fresh Cu, which is washed after being supported in ultrapure water and thoroughly cleaned with nitrogen gas, is about 41.6, the contact angle after the chemical mechanical polishing (CMP) process and cleaning should be maintained at 45 or less. When the contact angle exceeds 45, it indicates that the surface has been converted to a hydrophobic property by the corrosion inhibitor as described above. Since the cleaning process after chemical mechanical polishing (CMP) is intended to remove the organic contaminant layer remaining on the surface after polishing, it is preferable not to affect the surface except for the cleaning action. Therefore, it is preferable to maintain the degree of 45 degrees or less, which can be estimated that there is no change in the characteristics of the surface on the basis of the contact value before cleaning even in the contact angle after cleaning.

The cleaning liquid composition may be used in a dilution ratio of 1:10 to 1: 100 when cleaning the copper surface after the copper chemical mechanical polishing (CMP) process. If the dilution ratio is less than 1:10, it is difficult to evaluate the characteristics of the composition due to the low content of the cleaning liquid composition to be prepared, there may be a problem of poor productivity, and if it is greater than 1: 100, the storage content and stability over time There may be a problem.

The copper chemical mechanical polishing (CMP) process cleaning method of the present invention comprises the steps of chemical mechanical polishing (CMP) of the copper surface; And cleaning the polished copper surface using the cleaning liquid composition.

Hereinafter, the present invention will be described in more detail with reference to Examples and Comparative Examples. However, this is for illustrative purposes only, and the present invention is not limited thereto.

Example  1-1 to Example  3-2

To prepare a cleaning solution composition of the composition shown in Table 1 below.

Organic solvent
(weight%) Chelate reagents
(weight%) Corrosion inhibitor
(weight%) Example 1-1 KOH 5 EDTA 4.5 ATRA 0.3 Examples 1-2 KOH 8.33 EDTA 7.5 ATRA 0.5 Example 2-1 TMAH 5 EDTA 4.5 ATRA 0.3 Example 2-2 TMAH 8.33 EDTA 7.5 ATRA 0.5 Example 3-1 TMAH 5 Arginine 4.5 ATRA 0.3 Example 3-2 TMAH 8.33 Arginine 7.5 ATRA 0.5 Comparative Example 1 Commercial Cleaning Amount 1 Comparative Example 2 Frequent Cleaning Amount 2 Comparative Example 3 Commercial Cleaning Amount 3

The pH of the cleaning solution composition and the commercial cleaning solution thus prepared was measured, and the copper wafer was supported for 1 hour to check whether the copper wafer surface was discolored.

In addition, after cleaning the surface of the copper wafer subjected to the polishing chemical mechanical polishing process using the cleaning liquid composition of Examples 1-1 to 3-2, the contact angle was measured, and in order to check the degree of cleaning of the surface, FE-SEM (Field emission Electron microscope, field emission scanning electron microscope) and microscopic observation were performed to confirm the surface.

On the other hand, the cleaning liquid composition of Example 1-1, 2-1 was diluted 1:50 to perform the cleaning process, and measured before and after washing with a 4-point probe to indicate the amount removed based on the difference to confirm the amount removed per hour. The etching rate was measured by doing this.

Comparative example  1 to 3

Three commercial cleaning liquids were used as a comparative example. Measurement of physical properties and cleaning after the polishing process were performed in the same manner as in Example.

Table 2 below summarizes the physical properties of the cleaning solution compositions of Examples 1-1 to 3-2 and the commercial cleaning solutions of Comparative Examples 1 to 3 and the surface measurement results after cleaning using the same.

Stock pH After cleaning
Contact angle Discoloer occurrence after 1 hour FE-SEM Check Microscopic observation Etching rate
(Min / min, 1:50 dilution) Cu TEOS Example 1-1 12 41.2 Not occurring Great Great 3.7 1.9 Examples 1-2 12 44.5 Not occurring Good Good - - Example 2-1 10.5 27.7 Not occurring Good Good 2.0 2.0 Example 2-2 10.5 27.4 Not occurring Great Great - - Example 3-1 11 33.9 Not occurring Good Good - - Example 3-2 11 39.3 Not occurring Good Good - - Comparative Example 1 14 80.3 Not occurring usually Good - - Comparative Example 2 10.5 48.1 Not occurring flaw Good - - Comparative Example 3 13 47.6 Occur Great Great 4.0 2.0

As confirmed in Table 2, in pH, the commercial wash solutions of Comparative Examples 1 and 3 exhibited strong bases of 14 and 13, but the cleaning solution compositions of Examples 1-1 to 3-2 of the present invention were 10.5 to 12. The range is shown.

On the other hand, in the use of the actual washing | cleaning liquid, in consideration of diluting in considerable ratio and using it, pH stability with small change of pH at the time of dilution is calculated | required. 1 is a graph showing the pH change according to the dilution ratio of the cleaning solution compositions of Examples 1-1, 2-1 and 3-1 of the present invention and the commercial cleaning solutions of Comparative Examples 1 to 3. As shown in Figure 1, in the case of Example 1-1 and Example 2-1, it was confirmed that the pH stability according to the dilution ratio is very excellent.

As a result of measuring the contact angle after supporting the copper wafer for 1 minute, Examples 1-1 to 3-2 of the present invention had a maximum value of 44.5, but Comparative Example 1 showed a large value of 80.3.

On the other hand, as a result of observing the copper wafer for one hour and observed, Comparative Example 3 was found to have a severe discolor (discolor) problem, Examples 1-1 to 3-2 of the present invention does not occur such a discoloration Did. The commercial cleaning solution of Comparative Example 3 is very excellent in the other physical properties, there is a problem of discoloration occurs in the case of the most widely used product or the long-term support as described above, the present invention is excellent commercial of Comparative Example 3 in other physical properties Discoloration does not occur even if it has a characteristic equivalent to that of the cleaning solution for a long time, it can be seen that there is an advantage that can be applied elastically and efficiently in the operation of the cleaning process.

After the surface was examined under a microscope after chemical mechanical polishing and cleaning, all of the surface conditions were excellent or good. However, when the surface was measured by FE-SEM, defects were found in Comparative Example 2.

FIG. 2 is a TEM image of a copper surface after performing a cleaning process with the cleaning solution composition of Example 2-1 of the present invention, and FIG. 3 is a TEM image of a copper surface after performing a cleaning process with a commercial cleaning solution of Comparative Example.

As a result of comparing and measuring the six embodiments of the present invention and the commercial cleaning solution as described above, the pH of the stock solution and pH stability when dilution, contact angle, whether or not discoloration when supporting for a long time, the cleanliness of the surface after cleaning, surface defects, In the etching rate, it was confirmed that the cleaning liquid composition of the present invention showed superior characteristics as compared with the comparative example.

Claims (8)

Organic solvents comprising KOH, TMAH or both;
Chelating reagents comprising EDTA, arginine or both;
Preservatives; And
Pure water;
≪ / RTI >
The method of claim 1,
The organic solvent is a cleaning liquid composition, characterized in that 1 to 10% by weight of the cleaning liquid composition.
The method of claim 1,
The chelating reagent is a cleaning liquid composition, characterized in that 1 to 10% by weight of the cleaning liquid composition.
According to claim 1, wherein the corrosion inhibitor is a cleaning liquid composition, characterized in that 0.2 to 2% by weight of the cleaning liquid composition.
The cleaning solution composition of claim 1, wherein the cleaning solution composition has a pH of 10 to 12.5.
The cleaning liquid composition according to claim 1, wherein the cleaning liquid composition has a contact angle of 45 or less on the copper surface cleaned with the cleaning liquid composition after a copper chemical mechanical polishing (CMP) process.
The cleaning liquid composition according to claim 1, wherein the cleaning liquid composition is used at a dilution ratio of 1:10 to 1: 100 when cleaning the copper surface after a copper chemical mechanical polishing (CMP) process.
Chemical mechanical polishing (CMP) of the copper surface; And
Cleaning the polished copper surface using the cleaning liquid composition of claim 1;
(CMP) process. ≪ / RTI >

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