Chemical cleaning reagent and cleaning method for aluminum oxide ceramic parts

Abstract

The invention discloses a chemical cleaning reagent for aluminum oxide ceramic parts and a cleaning method. The chemical cleaning reagent comprises organic acid, a surfactant, a chelating agent, an oxidizing agent and deionized water. Aiming at the special pollution problem (such as trace metal ions, nano-scale particles and organic matters) of the aluminum oxide ceramic part in the 14-nm manufacturing process, the chemical cleaning reagent formula is optimized, pollutants on the surface of the ceramic part can be efficiently removed, and the cleanliness requirement of the 14-nm manufacturing process is met. The cleaning method comprises the steps of pretreatment, chemical cleaning, rinsing and drying, has the advantages of environmental protection, safety and no damage to the ceramic surface, and is suitable for the field of semiconductor manufacturing.

Description

Technical Field

[0001] The present invention belongs to the technical field of semiconductor manufacturing, and relates to a chemical cleaning reagent and a cleaning method for alumina ceramic parts, in particular to a chemical cleaning reagent formula and a cleaning method for alumina ceramic parts in the physical vapor deposition (PVD) process. Background Art

[0002] In the process of semiconductor manufacturing, the PVD process is widely used in thin film deposition. Alumina ceramic parts are often used in the cavities and key components of PVD equipment due to their excellent high temperature resistance and corrosion resistance. However, in the process of 14nm and below, trace pollutants (such as organic substances, metal ions, particles, etc.) on the surface of ceramic parts will seriously affect the quality of thin film deposition and the performance of devices. Traditional cleaning agents are difficult to completely remove these pollutants and cannot meet the cleaning requirements of alumina ceramic parts in the process of 14nm and below. Moreover, traditional cleaning agents usually contain strong acids, strong bases and other substances, which are extremely likely to cause environmental burden, operation risks and damage to the ceramic surface; at the same time, traditional cleaning methods are also easy to damage the ceramic surface. Therefore, it is of great significance to develop a chemical cleaning reagent formula and a cleaning method that are efficient, environmentally friendly and do not damage the ceramic surface. Summary of the Invention

[0003] The purpose of the present invention is to overcome the deficiencies of the prior art and provide a chemical cleaning reagent and a cleaning method for alumina ceramic parts. The present invention optimizes the chemical cleaning reagent formula for the special pollution problems (such as trace metal ions, nano-scale particles and organic substances) of alumina ceramic parts in the 14nm process, so as to solve the problems of poor cleaning effect and easy damage to the ceramic surface in the prior art, and ensure that the surface cleanliness after cleaning meets the requirements of the 14nm process. In addition, the cleaning method is optimized to further avoid damage to the ceramic surface while ensuring the cleaning efficiency.

[0004] The purpose of the present invention can be achieved by the following solutions:

[0005] In the first aspect, the present invention provides a chemical cleaning reagent for alumina ceramic parts, comprising the following components in weight percentage: organic acid 5%-15%, surfactant 0.5%-2%, chelating agent 1%-5%, oxidant 3%-10%, and the balance is deionized water.

[0006] As an embodiment of the present invention, the alumina ceramic parts are alumina ceramic parts in the process of 14nm and below.

[0007] As an embodiment of the present invention, the organic acid includes one or more of citric acid, oxalic acid, acetic acid, and tartaric acid. The organic acid of the present invention forms a stable water-soluble complex with metal ions through chelation, thereby stripping them from the surface.

[0008] As an embodiment of the present invention, the surfactant includes one or more of sodium dodecylbenzenesulfonate, cetyltrimethylammonium bromide, and cocamidopropyl betaine. The surfactant of the present invention can reduce the surface tension, enhance the wettability and permeability of the cleaning reagent, and help remove organic substances and particulate pollutants. The principle is that the surfactant adsorbs on the surface of the pollutants, causing them to detach from the ceramic surface and disperse in the solution.

[0009] As an embodiment of the present invention, the chelating agent includes one or more of disodium ethylenediaminetetraacetate, diethylenetriaminepentaacetic acid, hydroxyethylenediaminetriacetic acid, and tetrasodium glutamate diacetate. The chelating agent of the present invention further enhances the ability to remove metal ions, especially insoluble metal oxides. The principle is that the chelating agent forms a stable cyclic complex with metal ions, preventing them from redepositing on the ceramic surface.

[0010] As an embodiment of the present invention, the oxidizing agent includes one or more of hydrogen peroxide, ozone water, ammonium persulfate, sodium hypochlorite, and potassium permanganate. The oxidizing agent of the present invention can oxidize and decompose organic substances, and at the same time promote the dissolution of metal ions. The principle is that, for example, hydrogen peroxide releases reactive oxygen free radicals, oxidizes organic substances into small molecule substances (such as CO2 and H2O), and enhances the solubility of metal ions.

[0011] The present invention uses deionized water as a solvent to ensure uniform dispersion of each component and provide a rinsing medium.

[0012] In a second aspect, the present invention provides a cleaning method for alumina ceramic parts, including the following steps: immersing the pretreated alumina ceramic parts in the chemical cleaning reagent for chemical cleaning; then rinsing and drying the chemically cleaned alumina ceramic parts.

[0013] As an embodiment of the present invention, the pretreatment process includes: putting the alumina ceramic parts into deionized water and ultrasonically cleaning for 5 - 10 minutes. The purpose of pretreatment is to remove loose particles on the surface.

[0014] As an embodiment of the present invention, the temperature of the chemical cleaning is 40°C - 60°C, and the time is 20 - 40 minutes. Performing chemical cleaning within this temperature range ensures both the cleaning efficiency and avoids potential damage to the ceramic surface caused by high temperature.

[0015] Furthermore, ultrasonic or mechanical stirring is used to assist the chemical cleaning, which enhances the permeability of the cleaning reagent and the removal efficiency of pollutants, and is particularly suitable for the high cleanliness requirements in the 14nm process.

[0016] As an embodiment of the present invention, the rinsing process includes: rinsing 3-5 times with deionized water. The rinsing process ensures the complete removal of the chemical cleaning reagent and avoids the influence of residual reagents on subsequent processes.

[0017] As an embodiment of the present invention, nitrogen blowing or low-temperature drying is used for drying; the temperature of the low-temperature drying is 40-80°C. This avoids thermal stress damage to the ceramic surface during high-temperature drying and ensures the rapid drying of the components.

[0018] Compared with the prior art, the present invention has the following beneficial effects:

[0019] 1. The present invention optimizes the chemical cleaning reagent formula for the special pollution problems (such as trace metal ions, nanoscale particles, and organic substances) of alumina ceramic components in the 14nm process to ensure that the surface cleanliness after cleaning meets the requirements of the 14nm process. Among them, on the one hand, the synergistic effect of organic acids and chelating agents is utilized. That is, the organic acid initially removes metal ions through chelation, while the chelating agent further stabilizes these metal ions to prevent their re-deposition, significantly enhancing the removal ability of metal ions. On the other hand, the synergistic effect of surfactants and oxidants is utilized. That is, the surfactant reduces the surface tension of the oxidant, making it easier to penetrate into the micropores and defects on the ceramic surface, thereby improving the removal efficiency and effect of the oxidant on organic substances and particulate pollutants.

[0020] 2. The present invention realizes the comprehensive removal of organic substances, metal ions, and particulate pollutants through the reasonable ratio of organic acids, surfactants, chelating agents, and oxidants, avoiding problems such as serious influence on device performance or device failure caused by the residues of the organic substances, metal ions, and particulate pollutants; and maintaining its original physical and chemical properties; at the same time, avoiding the use of strong acids, strong bases, and toxic substances, reducing the environmental burden, operation risk, and damage to the ceramic surface. The formula is environmentally friendly and safe for operators.

[0021] 3. The present invention optimizes the cleaning method. By controlling the cleaning temperature, using ultrasonic / mechanical stirring assistance, multi-stage rinsing, and nitrogen blowing or low-temperature drying, further potential damage to the ceramic surface is avoided while ensuring the cleaning efficiency. In addition, the cleaning method of the present invention is simple and easy to be applied industrially. Detailed implementation mode

[0022] The following are specific embodiments to illustrate the present invention in detail. The following examples are implemented on the premise of the technical solution of the present invention, providing detailed implementation manners and specific operation processes, which will help those skilled in the art to further understand the present invention. It should be noted that the protection scope of the present invention is not limited to the following embodiments. Several adjustments and improvements made on the premise of the concept of the present invention all belong to the protection scope of the present invention.

[0023] Example 1

[0024] 1. Prepare the chemical cleaning reagent: 10% citric acid, 1% sodium dodecylbenzenesulfonate, 3% disodium ethylenediaminetetraacetate, 5% hydrogen peroxide, 81% deionized water.

[0025] 2. Put the alumina ceramic parts into deionized water and ultrasonically clean for 8 minutes.

[0026] 3. Immerse the parts in the chemical cleaning reagent and soak at 50 °C for 30 minutes, while assisted by ultrasonic cleaning.

[0027] 4. Rinse 4 times with deionized water.

[0028] 5. Dry the parts with nitrogen.

[0029] Example 2

[0030] 1. Prepare the chemical cleaning reagent: 8% oxalic acid, 1.5% sodium dodecylbenzenesulfonate, 4% disodium ethylenediaminetetraacetate, 6% hydrogen peroxide, 80.5% deionized water.

[0031] 2. Put the alumina ceramic parts into deionized water and ultrasonically clean for 10 minutes.

[0032] 3. Immerse the parts in the chemical cleaning reagent and soak at 60 °C for 20 minutes, while assisted by mechanical stirring.

[0033] 4. Rinse 5 times with deionized water.

[0034] 5. Dry the parts in a clean oven at low temperature (40 °C).

[0035] Comparative Example 1

[0036] The chemical cleaning reagent and cleaning method in this comparative example are basically the same as those in Example 1, except that citric acid is omitted from the chemical cleaning reagent, specifically: 1% sodium dodecylbenzenesulfonate, 3% disodium ethylenediaminetetraacetate, 5% hydrogen peroxide, 91% deionized water.

[0037] Comparative Example 2

[0038] The chemical cleaning reagent and cleaning method of this comparative example are basically the same as those of Example 1, except that disodium ethylenediaminetetraacetate is omitted from the chemical cleaning reagent, specifically: citric acid 10%, sodium dodecylbenzenesulfonate 1%, hydrogen peroxide 5%, deionized water 84%.

[0039] Comparative Example 3

[0040] The chemical cleaning reagent and cleaning method of this comparative example are basically the same as those of Example 1, except that sodium dodecylbenzenesulfonate is omitted from the chemical cleaning reagent, specifically: citric acid 10%, disodium ethylenediaminetetraacetate 3%, hydrogen peroxide 5%, deionized water 82%.

[0041] Comparative Example 4

[0042] The chemical cleaning reagent and cleaning method of this comparative example are basically the same as those of Example 1, except that hydrogen peroxide is omitted from the chemical cleaning reagent, specifically: citric acid 10%, sodium dodecylbenzenesulfonate 1%, disodium ethylenediaminetetraacetate 3%, deionized water 86%.

[0043] Performance Test

[0044] Experimental Scheme Design:

[0045] 1. Instruments used for detection:

[0046] 1) Metal ion removal rate: Detect the concentration change of metal ions (such as Fe, Cu, Al) on the ceramic surface before and after cleaning by inductively coupled plasma mass spectrometry (ICP-MS);

[0047] 2) Nanoscale particle removal rate: Detect the quantity and size distribution of particles on the ceramic surface before and after cleaning by scanning electron microscopy (SEM) and particle counter;

[0048] 3) Organic matter removal rate: Detect the residual amount of organic matter on the ceramic surface before and after cleaning by Fourier transform infrared spectroscopy (FTIR) and total organic carbon (TOC) analysis;

[0049] 2. Experimental method:

[0050] 1) Metal ion detection:

[0051] Measure the concentration of metal ions on the ceramic surface before and after cleaning using ICP-MS, and calculate the removal rate.

[0052] 2) Nanoscale particle detection:

[0053] Observe the particle distribution on the ceramic surface before and after cleaning using SEM, and count the number of particles through a particle counter.

[0054] 3) Organic matter detection:

[0055] The characteristic peak intensity changes of organic substances on the ceramic surface before and after cleaning were analyzed using FTIR, and the organic carbon content was measured by TOC analysis.

[0056] The metal ion detection results are shown in Table 1:

[0057] Table 1 Comparison data of metal ion removal rates

[0058] Group Fe Removal Rate (%) Cu Removal Rate (%) Al Removal Rate (%) Example 1 99.2 98.8 99.5 Example 2 98.9 98.5 99.3 Comparative Example 1 65.3 62.8 68.5 Comparative Example 2 60.8 58.4 63.2 Comparative Example 3 85.2 83.7 87.5 Comparative Example 4 82.5 80.3 85.7

[0059] As can be seen from Table 1, the metal ion removal rates of Examples 1-2 are significantly higher than those of Comparative Examples 1-4. In particular, the removal rates of Comparative Examples 1-2 (omitting organic acids or chelating agents) decreased significantly, proving the key role of organic acids and chelating agents in removing metal ions.

[0060] The nano-sized particle detection results are shown in Table 2:

[0061] Table 2 Comparison data of nano-sized particle removal rates

[0062] Group Reduction in Particle Number (%) Particle Size Distribution (%) Example 1 98.7 Above 90% Example 2 98.5 Above 90% Comparative Example 1 70.2 Above 60% Comparative Example 2 68.5 Above 55% Comparative Example 3 60.3 Above 50% Comparative Example 4 75.4 Above 70%

[0063] As can be seen from Table 2, the particle removal rates of Examples 1-2 are significantly higher than those of Comparative Examples 1-4. In particular, the removal rate of Comparative Example 3 (omitting the surfactant) decreased significantly, proving the important role of the surfactant in removing nano-sized particles.

[0064] The organic substance detection results are shown in Table 3:

[0065] Table 3 Comparison data of organic substance removal rates

[0066] Group Reduction in FTIR Characteristic Peak Intensity (%) Reduction in TOC Content (%) Example 1 99.1 98.9 Example 2 98.8 98.7 Comparative Example 1 71.5 70.8 Comparative Example 2 69.2 68.7 Comparative Example 3 65.8 64.2 Comparative Example 4 55.3 54.8

[0067] As can be seen from Table 3, the organic substance removal rates of Examples 1-2 are significantly higher than those of Comparative Examples 1-4. In particular, the removal rate of Comparative Example 4 (omitting hydrogen peroxide) decreased significantly, proving the key role of hydrogen peroxide in removing organic substances.

[0068] In summary, due to the synergistic effect of the four components (organic acid, surfactant, chelating agent, and oxidant) in the present invention, the absence of any one component will significantly reduce the cleaning effect, resulting in the surface cleanliness not meeting the requirements of the 14nm process.

[0069] The specific embodiments of the present invention have been described above. It should be understood that the present invention is not limited to the above specific embodiments, and those skilled in the art can make various deformations or modifications within the scope of the claims, which do not affect the essence of the present invention.

Claims

1. A chemical cleaning agent for alumina ceramic parts, characterized in that: The composition comprises the following components in weight percentage: 5%-15% of organic acid, 0.5%-2% of surfactant, 1%-5% of chelating agent, 3%-10% of oxidant, and the balance is deionized water; The alumina ceramic component is an alumina ceramic component with a process of 14nm and below.

2. The chemical cleaning agent according to claim 1, characterized in that: The organic acid includes one or more of citric acid, oxalic acid, acetic acid and tartaric acid.

3. The chemical cleaning agent according to claim 1, characterized in that: The surfactant includes one or more of sodium dodecylbenzene sulfonate, hexadecyltrimethylammonium bromide, and cocamidopropyl betaine.

4. The chemical cleaning agent according to claim 1, characterized in that: The chelating agent includes one or more of disodium ethylenediaminetetraacetate, diethylenetriaminepentaacetic acid, hydroxyethylethylenediaminetriacetic acid, and tetrasodium glutamate diacetate.

5. The chemical cleaning agent according to claim 1, characterized in that: The oxidant includes one or more of hydrogen peroxide, ozone water, ammonium persulfate, sodium hypochlorite, and potassium permanganate.

6. A method for cleaning alumina ceramic parts, characterized in that: The following steps are involved: The pretreated alumina ceramic parts are immersed in the chemical cleaning agent as described in any one of claims 1 to 5 for chemical cleaning; and the chemically cleaned alumina ceramic parts are then rinsed and dried.

7. The cleaning method according to claim 6, characterized in that: The pretreatment process includes: placing the alumina ceramic parts in deionized water and ultrasonically cleaning them for 5-10 minutes.

8. The cleaning method according to claim 6, characterized in that: The chemical cleaning also includes at least one of the following technical features: The temperature of the chemical cleaning is 40°C-60°C and the time is 20-40 minutes; The chemical cleaning is assisted by ultrasonic or mechanical stirring.

9. The cleaning method according to claim 6, characterized in that: The rinsing process includes: rinsing with deionized water for 3-5 times.

10. The cleaning method according to claim 6, characterized in that: The drying is carried out by nitrogen blowing or low temperature drying; the temperature of the low temperature drying is 40-80°C.