Post-chemical-mechanical-polishing cleaning composition as well as preparation method and application thereof

Abstract

The invention provides a chemical mechanical polishing post-cleaning composition as well as a preparation method and application thereof. The chemical mechanical polishing post-cleaning composition comprises the following components in parts by weight: 1-15 parts of a porphyrin derivative; 2 to 10 parts of alkyl glycoside; 0.5 to 5 parts of organic acid; 0.1-1 part of a corrosion inhibitor; and 70-90 parts of ultrapure water. The invention further discloses a preparation method of the cleaning composition after CMP and application of the cleaning composition in the field of cleaning residues on the surface of a wafer after CMP. The cleaning composition after chemical mechanical polishing can effectively remove residual pollutants such as Co-BTA, metal ions and particles on the Co surface, and high cleanliness and flatness of the Co surface are guaranteed.

Description

Technical Field

[0001] The present invention relates to wafer cleaning composition technology, in particular to a post-chemical mechanical polishing cleaning composition and a preparation method and application thereof. Background Art

[0002] With the continuous advancement of integrated circuit (IC) technology, the feature size of semiconductor devices has continued to shrink in line with Moore's Law. Copper (Cu) has gradually replaced aluminum as the preferred interconnect material due to its low resistivity and excellent electromigration resistance. In this process, researchers have widely used tantalum and tantalum nitride (Ta / TaN) bilayer structures as diffusion barriers in Cu interconnects to effectively inhibit the diffusion of Cu into the dielectric region. However, as the process node drops below 14nm, the traditional Ta / TaN barrier layer experiences increased resistivity and Cu deposition challenges. When the process node is further reduced to 10nm and below, the resistivity of Cu rises sharply due to intensified electron scattering on the sidewalls and grain boundaries. In addition, under high temperature and high current density environments, the electromigration tendency of Cu is exacerbated, posing a serious threat to the stability and service life of the circuit.

[0003] Cobalt (Co) has attracted widespread attention in the industry due to its excellent thermal stability, gap-filling performance, and strong adhesion to Cu wiring. As a new barrier layer material, Co can effectively solve the common gap-filling and pinch-off problems in Ta / TaN, thereby reducing the interconnect signal (RC) delay and further optimizing the performance of Cu interconnects. In addition, below the 10nm process node, Co exhibits a lower mean electron free path and better deposition performance, making it one of the most promising candidate materials to replace Cu interconnects. With the continuous improvement of integrated circuit integration and the continuous reduction of feature sizes, multi-layer metal interconnect materials have put forward more stringent requirements on surface flatness and defect control. However, the increase in the number of interconnect layers causes the surface morphology to become rough, which in turn affects the process efficiency and the accuracy of the desired results. Therefore, in order to obtain the ideal surface morphology, the chemical mechanical planarization (CMP) process came into being.

[0004] However, after the CMP process, certain components in the polishing liquid (such as SiO2 nanoparticles and organic matter) will inevitably remain on the Co surface, forming contaminants and hindering the effective implementation of subsequent processes, thereby affecting the electrical performance and stability of the device. Therefore, before any subsequent steps, an effective post-CMP cleaning process is required. By adjusting the chemical composition combination and proportion of the cleaning agent, the contaminants remaining on the Co surface can be effectively removed to ensure high cleanliness and high flatness of the surface and maintain the excellent performance of the device. Traditional post-CMP cleaning agents mainly use aminocarboxylic acid chelating agents (such as EDTA, DTPA), organic acids (such as citric acid, oxalic acid) or strong oxidizing acid (such as sulfuric acid, nitric acid, hydrogen peroxide) systems. Traditional post-CMP cleaning agents have different degrees of problems that cannot completely remove Co-BTA complexes, metal ions and particles, and can no longer meet the increasingly high demands for cleanliness and flatness. Summary of the Invention

[0005] The purpose of the present invention is to address the problem that traditional cleaning agents cannot completely remove Co-BTA complexes, metal ions and particles, and to propose a post-chemical mechanical polishing cleaning composition. The post-chemical mechanical polishing cleaning composition can effectively remove contaminants (such as Co-BTA, metal ions and particles) remaining on the Co surface, ensuring high cleanliness and flatness of the Co surface.

[0006] It should be noted that, in the present invention, unless otherwise specified, the specific meaning of "including" in relation to composition limitations and descriptions includes both open-ended "including", "comprising", etc. and similar meanings, as well as closed-ended "composed of", "composed of", etc. and similar meanings.

[0007] To achieve the above object, the technical solution adopted by the present invention is: a cleaning composition after chemical mechanical polishing, comprising the following components in the following weight proportions:

[0008]

[0009] Furthermore, the porphyrin derivative is one or more of 5-phenyl-10,15,20-tris(4-aminophenyl)porphyrin, meso-tetrakis(4-aminophenyl)porphyrin, meso-tetrakis(4-carboxyphenyl)porphyrin and 5,10,15,20-tetrakis(3,5-dicarboxyphenyl)porphyrin.

[0010] Furthermore, the porphyrin derivative is preferably 5-phenyl-10,15,20-tris(4-aminophenyl)porphyrin and / or meso-tetrakis(4-aminophenyl)porphyrin.

[0011] Furthermore, the porphyrin derivative is most preferably meso-tetrakis(4-aminophenyl)porphyrin.

[0012] Furthermore, the porphyrin derivative is preferably 3-12 parts.

[0013] There are four aminophenyl substituents at the meso position of porphyrin (i.e., the connection point of the porphyrin ring). This amino group can coordinate with metal ions. Because the cobalt-ammonia complex has a higher stability constant than Co-BTA, it will promote ligand exchange to cause Co-BTA to dissociate and form a cobalt-ammonia complex, thereby removing Co-BTA from the Co surface. At the same time, the amino group (-NH2) is an electron-donating group. It donates electrons to the π electron cloud of the porphyrin ring through its lone pair of electrons, thereby enhancing the electron cloud density of the porphyrin ring and making it easier to coordinate with metal ions. This allows the porphyrin ring in the porphyrin derivative to dissociate Co from Co-BTA. 2+ Coordinate to form a complex, remove Co-BTA, and coordinate with the metal ions on the Co surface to remove the residual metal ions on the Co surface. Due to the strong electron donation ability of the amino group, the complex formed by the porphyrin ring and the metal ion is relatively stable and not easy to dissociate, effectively avoiding Co 2+ With BTA - Combine again.

[0014] Furthermore, the alkyl glycoside is a C10-C16 alkyl glycoside.

[0015] Furthermore, the alkyl glycoside is preferably one or more of decyl glucoside, undecyl glucoside, dodecyl glucoside and hexadecyl-D-glucoside.

[0016] Furthermore, the alkyl glycoside is most preferably hexadecyl-D-glucoside.

[0017] Furthermore, the alkyl glycoside is preferably 4-8 parts.

[0018] The hydrophobic long chain of the alkyl glycoside can enter the porphyrin ring of the porphyrin derivative, directly destroy the chemical bond between Co-BTA, and forcibly bind to the Co in the Co-BTA complex. 2+ Coordination, forming a stable and soluble cobalt-ammonia complex, to achieve the effect of removing Co-BTA; at the same time, alkyl glycosides and porphyrin derivatives can form host-guest inclusion complexes to jointly remove BTA - "Wrap" it up to prevent BTA - With Co 2+ Combined with other ingredients, the effect of completely removing Co-BTA is achieved.

[0019] Furthermore, the mass ratio of the porphyrin derivative to the alkyl glycoside is 1:1-7.

[0020] Furthermore, the mass ratio of the porphyrin derivative to the alkyl glycoside is preferably 1:1-6.

[0021] Furthermore, the organic acid is one or more of tartaric acid, malic acid, malonic acid, succinic acid, glutaric acid, glycolic acid, triglyceric acid, pyruvic acid, glyoxylic acid, citric acid, maleic acid and iminoacetic acid.

[0022] Furthermore, the organic acid is preferably one or more of glycolic acid, tartaric acid and malonic acid.

[0023] Furthermore, the organic acid is most preferably tartaric acid.

[0024] Furthermore, the organic acid is preferably 2-4 parts.

[0025] The presence of long-chain alkyl groups gives alkyl glycosides excellent dispersibility, hydrophobicity, and film-forming ability, which in turn gives them excellent surface activity, allowing them to quickly diffuse and fully wet the interface between the particles and the Co surface, even to the smallest gaps. In this process, the organic acid breaks the Si-O-Co chemical bond through the undercutting effect, thereby separating more SiO2 particles from the Co surface. The preferential adsorption characteristics of the alkyl glycoside allow it to quickly attach to the chemical bonds just broken by the organic acid and interact with other adsorbed particles through van der Waals forces, constructing an isolation layer with a hydrophilic interior and a hydrophobic exterior, thereby improving the removal ability of SiO2 nanoparticles.

[0026] Furthermore, the corrosion inhibitor is one or more of 5-aminotetrazole, 3-amino-1,2,4-triazole and 3,5-diamino-1,2,4-triazole.

[0027] Furthermore, the corrosion inhibitor is preferably 3,5-diamino-1,2,4-triazole.

[0028] Furthermore, the corrosion inhibitor is preferably 0.3-0.8 parts.

[0029] Furthermore, the ultrapure water is deionized water with a resistance of ≥18 MΩ.

[0030] Furthermore, the ultrapure water is preferably 80 parts.

[0031] Another object of the present invention is to disclose a method for preparing a post-chemical mechanical polishing cleaning composition, comprising the following steps: weighing each component separately, mixing and dissolving all components completely, and preparing the post-chemical mechanical polishing cleaning composition.

[0032] Another object of the present invention is to disclose the use of a post-chemical mechanical polishing cleaning composition in the field of cleaning residues on the surface of wafers after CMP.

[0033] Furthermore, the post-chemical mechanical polishing cleaning composition is particularly suitable for cleaning residues on the surface of cobalt wafers after CMP.

[0034] Furthermore, the method for cleaning a cobalt wafer after CMP using the post-chemical mechanical polishing cleaning composition is as follows:

[0035] Step 1: diluting the post-chemical mechanical polishing cleaning composition with ultrapure water to 20-100 times, and then soaking a cobalt wafer with the aqueous solution to obtain a soaked cobalt wafer;

[0036] Step 2: Rinse the soaked cobalt wafer in ultrapure water and blow dry with nitrogen, thereby completing the cleaning process of the cobalt wafer.

[0037] Furthermore, the soaking temperature in step 1 is 20-30° C., and the soaking time is 30-120 seconds.

[0038] Furthermore, in step 2, rinse three times in ultrapure water.

[0039] The post-chemical mechanical polishing cleaning composition of the present invention, its preparation method, and its application have the following advantages compared with the prior art:

[0040] 1) The porphyrin derivatives selected in the present invention have multiple aminophenyl or carboxylphenyl substituents at the connection point of the porphyrin ring. This amino or carboxyl group can coordinate with metal ions. Because the cobalt ammonia complex and the cobalt carboxyl complex have higher stability constants than Co-BTA, they will promote ligand exchange, causing Co-BTA to dissociate and form a cobalt ammonia complex or a cobalt carboxyl complex, thereby removing Co-BTA from the Co surface. Moreover, the porphyrin derivatives selected in the present invention can also cooperate with alkyl glycosides to further remove Co-BTA. At the same time, the porphyrin ring, amino or carboxyl group can chelate metal ions, thereby removing residual metal ions from the Co surface. In addition, the introduction of amino or carboxyl groups increases the hydrophilicity of the molecule, thereby increasing the solubility of the porphyrin derivative. The amino group (-NH2) in 5-phenyl-10,15,20-tris(4-aminophenyl)porphyrin and meso-tetra(4-aminophenyl)porphyrin is an electron-donating group. Its lone pair of electrons can donate electrons to the π electron cloud of the porphyrin ring, thereby enhancing the electron cloud density of the porphyrin ring and making it easier to coordinate with metal ions. This makes the porphyrin ring in 5-phenyl-10,15,20-tris(4-aminophenyl)porphyrin and meso-tetra(4-aminophenyl)porphyrin easier to react with the Co dissociated from Co-BTA. 2+ Coordinate to form a complex, remove Co-BTA and coordinate with the metal ions on the Co surface to remove the residual metal ions on the Co surface. Because the amino group has a strong electron donation ability, the complex formed by the porphyrin ring and the metal ion is relatively stable and not easy to dissociate, which avoids the Co 2+ With BTA - The recombination of.

[0041] 2) The hydrophobic chain of the alkyl glycoside selected in the present invention can enter the porphyrin ring of the porphyrin derivative, and the two produce a synergistic effect, directly destroying the chemical bond between Co-BTA and forcibly binding to the Co in the Co-BTA complex. 2+ The coordination generates a stable and soluble cobalt-ammonia complex, achieving the effect of removing Co-BTA. At the same time, the hydrophobic chain of the alkyl glycoside enters the porphyrin ring of the porphyrin derivative to form a host-guest inclusion complex, so that the alkyl glycoside and the porphyrin derivative work together to remove BTA. - "Wrap" it up to prevent BTA - With Co 2+ Combine again to achieve the effect of completely removing Co-BTA.

[0042] 3) The presence of long-chain alkyl groups gives alkyl glycosides excellent dispersibility, hydrophobicity, and film-forming ability, which in turn gives them good surface activity, allowing them to quickly diffuse and fully wet the interface between the particles and the Co surface, and even the tiny gaps. In this process, the organic acid breaks the Si-O-Co chemical bond through the undercutting effect, thereby separating more SiO2 particles on the Co surface. The preferential adsorption characteristics of the alkyl glycoside allow it to quickly attach to the chemical bonds just broken by the organic acid and interact with other adsorbed particles through van der Waals forces, constructing an isolation layer with a hydrophilic interior and a hydrophobic exterior, thereby increasing the removal of SiO2 nanoparticles.

[0043] 4) The cleaning composition after chemical mechanical polishing of the present invention is environmentally friendly, pollution-free, and has low volatile loss. After cleaning, it only needs to be rinsed with pure water, which is harmless to the environment and human body.

[0044] In summary, the post-chemical mechanical polishing cleaning composition of the present invention has good application prospects and large-scale promotion potential in the field of post-CMP cleaning. BRIEF DESCRIPTION OF THE DRAWINGS

[0045] Figure 1 This is a 100x microscope image of a Co wafer before cleaning.

[0046] Figure 2 This is a microscope picture of the Co wafer after cleaning in comparative example 1 at 100 times magnification.

[0047] Figure 3 This is a microscope image of the Co wafer after cleaning in Example 1 at 100 times magnification. DETAILED DESCRIPTION

[0048] The present invention will be further described below with reference to the following examples. The following description of the technical features is based on representative embodiments and specific examples of the present invention, but the present invention is not limited to these embodiments and specific examples. It should be noted that:

[0049] Unless otherwise stated, the units used in this specification are international standard units, and the numerical values ​​and numerical ranges appearing in the present invention should be understood to include the inevitable systematic errors in industrial production.

[0050] In this specification, the numerical range expressed using "a numerical value A to a numerical value B" means a range including the endpoints A and B.

[0051] In this specification, the numerical range expressed using "above" or "below" means a numerical range including the number.

[0052] In this specification, the use of "may" includes both the meaning of performing a certain process and the meaning of not performing a certain process.

[0053] In this specification, the use of "optional" or "optional" indicates that certain substances, components, execution steps, application conditions and other factors are used or not used.

[0054] In this specification, when "normal temperature" or "room temperature" is used, the temperature may be 15-25°C.

[0055] In this manual, the reagents or instruments used without indicating the manufacturer are all conventional products that can be obtained through commercial purchase.

[0056] Examples 1-8

[0057] Examples 1-8 disclose a variety of post-chemical mechanical polishing cleaning compositions, the components and weight ratios of which are shown in Table 1. The preparation method is as follows: weigh each component separately, mix and dissolve all components completely to prepare the post-chemical mechanical polishing cleaning composition.

[0058] Table 1 Components and ratios of the cleaning compositions after chemical mechanical polishing of Examples 1-8

[0059]

[0060] Comparative Examples 1-4

[0061] Comparative Examples 1-4 disclose a variety of cleaning compositions, the components and dosage ratios of which are shown in Table 2. The preparation methods are the same as those of Example 1.

[0062] Table 2 Components and ratios of cleaning compositions of Comparative Examples 1-4

[0063]

[0064] The chemical mechanical polishing cleaning compositions of Examples 1-8 and the chemical mechanical polishing cleaning compositions of Comparative Examples 1-4 were tested respectively. The test results are shown in Table 3:

[0065] Table 3 Test data

[0066] Example / Comparative Example Cleaning effect Surface contact angle / ° Roughness / μm Example 1 No residue after cleaning 42.0 0.72 Example 2 No residue after cleaning 46.4 1.23 Example 3 No residue after cleaning 45.6 1.10 Example 4 No residue after cleaning 45.0 1.06 Example 5 No residue after cleaning 44.8 0.99 Example 6 No residue after cleaning 44.5 0.94 Example 7 No residue after cleaning 43.2 0.83 Example 8 No residue after cleaning 44.0 0.89 Comparative Example 1 Residue after cleaning 57.9 2.70 Comparative Example 2 Residue after cleaning 55.2 2.29 Comparative Example 3 Residue after cleaning 52.3 2.05 Comparative Example 4 Residue after cleaning 53.6 1.98

[0067] As can be seen from Table 3, all embodiments achieve "no residue", while the comparative examples all have residue; the surface contact angles of the embodiments are all less than the surface contact angle of 48° of a fresh Co wafer, while the surface contact angles of the comparative examples are all greater than the surface contact angle of 48° of a fresh Co wafer, indicating that after cleaning the embodiments, the surface is hydrophilic and has no residue, while after cleaning the comparative examples, the surface is hydrophobic and has residue. In addition, the roughness of the Co wafer surface after cleaning in all embodiments is lower than the roughness of the Co wafer surface after cleaning in the comparative examples, indicating that the Co surface after cleaning in the embodiments is smoother. In summary, it is proved that the synergistic effect of porphyrin derivatives, alkyl glycosides and organic acids is indispensable.

[0068] Figure 1 This is a 100x microscope image of a Co wafer before cleaning. Figure 2 This is a microscope picture of the Co wafer after cleaning in comparative example 1 at 100 times magnification. Figure 3 This is a 100x microscope image of the Co wafer after cleaning in Example 1. It can be seen that there are obvious residual contaminants on the wafer surface before cleaning; the surface residues on the surface of the comparative example 1 were not completely removed after cleaning; and there was no residue on the surface after cleaning in Example 1, and the surface flatness was high.

[0069] in:

[0070] The test method for cleaning effect is:

[0071] After the Co wafer has undergone the grinding and polishing steps in the back-end process, a large amount of organic residues and particles remain on the wafer. The cleaning compositions of the above embodiments and comparative examples of the present invention are used to clean the Co wafer. The cleaning method includes the following steps:

[0072] Step 1: Take a microscope picture of the Co wafer before cleaning;

[0073] Step 2: diluting the post-chemical mechanical polishing cleaning composition with ultrapure water to 100 times, and then using the aqueous solution to soak a Co wafer at room temperature of 25° C. for 50 seconds to obtain a soaked Co wafer;

[0074] Step 3: Rinse the soaked Co wafer in ultrapure water for at least three times, and then blow dry the surface with nitrogen, thereby completing the cleaning process of the Co wafer;

[0075] Step 4: Take a microscope picture of the cleaned Co wafer.

[0076] The ultrapure water used in the above steps is deionized water with a resistance of at least 18 MΩ.

[0077] The test method for surface contact angle is:

[0078] In order to characterize the hydrophilicity of the Co wafer surface after Co-CMP post-cleaning, a contact angle meter was used to test it.

[0079] Deionized water was dropped onto the cleaned Co wafer surface and the contact angle was measured using a contact angle meter to determine the hydrophilicity and hydrophobicity of the Co wafer surface. The BTA removal was then determined based on the hydrophilicity and hydrophobicity of the Co wafer surface.

[0080] The surface of a fresh Co wafer is hydrophilic (the contact angle of a fresh Co wafer is 48°. A value lower than this indicates that there is no residue on the Co surface, and a value higher than this indicates that there is residue on the Co surface). The contact angle of deionized water on the surface of the Co wafer is small. When a BTA film exists on the surface of the Co wafer, the surface of the Co wafer is hydrophobic, and the contact angle of deionized water on the surface of the Co wafer is large.

[0081] The test method for roughness (Ra) is:

[0082] The above-mentioned post-chemical mechanical polishing cleaning composition was diluted 100 times with ultrapure water to prepare a diluted cleaning solution, and then a cobalt wafer was placed in the diluted cleaning solution and immersed at 25° C. for 50 seconds. After rinsing with deionized water, it was blown dry with nitrogen gas, and the Ra value was measured by AFM.

[0083] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the above embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A post-chemical mechanical polishing cleaning composition, characterized in that The composition comprises the following components in the following weight ratios:

2. The post-chemical mechanical polishing cleaning composition according to claim 1, wherein The porphyrin derivative is one or more of 5-phenyl-10,15,20-tris(4-aminophenyl)porphyrin, meso-tetrakis(4-aminophenyl)porphyrin, meso-tetrakis(4-carboxyphenyl)porphyrin and 5,10,15,20-tetrakis(3,5-dicarboxyphenyl)porphyrin.

3. The post-chemical mechanical polishing cleaning composition according to claim 1, wherein The alkyl glycoside is a C10-C16 alkyl glycoside.

4. The post-chemical mechanical polishing cleaning composition according to claim 1, wherein The mass ratio of the porphyrin derivative to the alkyl glycoside is 1:1-7.

5. The post-chemical mechanical polishing cleaning composition according to claim 1, wherein The organic acid is one or more of tartaric acid, malic acid, malonic acid, succinic acid, glutaric acid, glycolic acid, triglyceric acid, pyruvic acid, glyoxylic acid, citric acid, maleic acid and iminodiacetic acid.

6. The post-chemical mechanical polishing cleaning composition according to claim 1, wherein The corrosion inhibitor is one or more of 5-aminotetrazole, 3-amino-1,2,4-triazole and 3,5-diamino-1,2,4-triazole.

7. A method for preparing the cleaning composition after chemical mechanical polishing according to any one of claims 1 to 6, characterized in that: The method comprises the following steps: weighing each component respectively, mixing and dissolving all the components completely, and preparing a post-chemical mechanical polishing cleaning composition.

8. Use of the post-chemical mechanical polishing cleaning composition according to any one of claims 1 to 6 in the field of cleaning residues on wafer surfaces after CMP.

9. The application according to claim 8, characterized in that: The method for cleaning a cobalt wafer after CMP using a post-chemical mechanical polishing cleaning composition is as follows: Step 1: diluting the post-chemical mechanical polishing cleaning composition with ultrapure water to 20-100 times, and then soaking a cobalt wafer with the aqueous solution to obtain a soaked cobalt wafer; Step 2: Rinse the soaked cobalt wafer in ultrapure water and blow dry with nitrogen, thereby completing the cleaning process of the cobalt wafer.

10. The use according to claim 9, characterized in that: Step 1: The soaking temperature is 20-30°C and the soaking time is 30-120s.

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