A semiconductor chip post-CMP cleaning liquid, its preparation method and application

Abstract

The present invention provides a semiconductor chip post-CMP cleaning liquid, a preparation method and application thereof, wherein the semiconductor chip post-CMP cleaning liquid comprises the following components in weight proportion: 1-10 parts of an additive; 1-7 parts of a corrosion inhibitor; 1-10 parts of an organic base; 80-90 parts of ultrapure water; the additive is preferably N-(9-((1R, 3R, 4R, 7S)-1-((bis(4-methoxyphenyl)(phenyl)methoxy)methyl)-7-hydroxy-2,5-dioxabicyclo[2.2.1]heptane-3-yl)-9H-purine-6-yl)benzamide. The semiconductor chip post-CMP cleaning liquid of the present invention is safe, environmentally friendly, and highly efficient, has no corrosion to semiconductor chips, can complete cleaning under pure immersion process conditions without the need for an ultrasonic process, and has very good application prospects and large-scale industrial promotion potential in the field of semiconductor chip cleaning.

Description

Technical Field

[0001] The present invention relates to semiconductor chip cleaning liquid technology, and in particular to a semiconductor chip post-CMP cleaning liquid, and a preparation method and application thereof. Background Art

[0002] In the manufacturing process of integrated circuits, the chemical mechanical polishing (CMP) process is used to remove excess deposits on the surface of copper interconnect wafers to obtain a highly flat wafer surface, but pollutants such as metal ions, particles and organic matter are introduced during the flattening process. The post-CMP cleaning process needs to effectively remove pollutants on the wafer surface. The post-CMP cleaning process needs to effectively remove pollutants on the wafer surface to obtain a high-quality wafer surface. Particle contamination is the main target of post-CMP cleaning. During the cleaning process, the residual particle contaminants on the wafer surface should be removed as much as possible, and at the same time, the copper wafer surface should not be corroded by the cleaning solution.

[0003] The composition and components of the cleaning solution play a decisive role in the cleaning quality and efficiency. Traditional post-CMP cleaning solutions are divided into two categories: acidic and alkaline. Acidic cleaning solutions are mainly citric acid, dilute hydrofluoric acid (HF), etc. Some cleaning solutions are highly toxic and volatile, and they are severely corrosive after cleaning, affecting subsequent processes, such as reduced roughness and yield. There is also a type of alkaline cleaning solution mainly composed of tetramethylammonium hydroxide (TMAH), tetraethylammonium hydroxide (TEAH), ammonium hydroxide (NH4OH), etc. Most of them are highly corrosive and easily cause problems such as increased surface roughness and excessive substrate loss after cleaning. That is, in the actual application process, traditional post-CMP cleaning solutions have the problem of corroding semiconductor chips to varying degrees.

[0004] Corrosion is an important defect of copper wiring wafer after CMP. Metal corrosion refers to the phenomenon of damage caused by electrochemical or chemical reactions in the surrounding medium, which leads to the degradation (or complete loss) of the original physical and chemical properties of the metal, making the products made of it unusable. Whether for CMP polishing liquid or post-CMP cleaning liquid, the influence of corrosion must be eliminated. Summary of the invention

[0005] The purpose of the present invention is to propose a semiconductor chip post-CMP cleaning solution to address the problem of corrosion of semiconductor chips by traditional post-CMP cleaning solutions. The cleaning solution is safe, environmentally friendly and efficient. It can complete cleaning under pure immersion process conditions without the need for ultrasonic technology and does not corrode semiconductor chips.

[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 semiconductor chip post-CMP cleaning solution, comprising the following components in weight proportions:

[0008] 1-10 parts of additives;

[0009] Corrosion inhibitor 1-7 parts;

[0010] 1-10 parts of organic base;

[0011] 80-90 parts of ultrapure water;

[0012] The additive is one or more of N-(9-((1R,3R,4R,7S)-1-((bis(4-methoxyphenyl)(phenyl)methoxy)methyl)-7-hydroxy-2,5-dioxabicyclo[2.2.1]heptane-3-yl)-9H-purine-6-yl)benzamide, 2-hydroxy-3-methoxybenzamide, N-hydroxy-4-methoxy-naphthalene-1-carboxamide, N-hydroxy-5-methoxy-2-pyridinecarboxamide and (Z)-N'-hydroxy-6-methoxypicolinamide.

[0013] Further, the additive is N-(9-((1R,3R,4R,7S)-1-((bis(4-methoxyphenyl)(phenyl)methoxy)methyl)-7-hydroxy-2,5-dioxabicyclo[2.2.1]heptane-3-yl)-9H-purine-6-yl)benzamide, and its structural formula is as follows:

[0014]

[0015] The additive of the present invention contains multiple heteroatoms and has more lone pairs of electrons that can form a complex with copper, thereby removing Cu-BTA. The additive contains multiple hydrophilic methoxy groups and multiple benzene rings, which improves its own hydrophilicity and water solubility, and at the same time, it has strong hydrogen bonding effects within and between molecules, has a stable rigid structure, further improves the solubility of the compound, and provides a basis for the stability of the subsequent solution system. At the same time, the C=N bond of the additive can be adsorbed on the copper metal surface, and the double bond in the benzene ring structure contained in it can also interact with the copper surface, so that the additive is easy to form a passivation film while forming a complex with copper, has good film-forming stability, reduces the contact between the copper surface and the corrosive medium, and thus has an excellent effect of inhibiting metal corrosion on the chip.

[0016] Furthermore, the additive is 4-8 parts.

[0017] Furthermore, the corrosion inhibitor is one or more of triethylene glycol di(p-toluenesulfonate), isopropyl ethanesulfonate and isopropyl benzenesulfonate.

[0018] Furthermore, the corrosion inhibitor is selected as triethylene glycol di(p-toluenesulfonate).

[0019] Furthermore, the corrosion inhibitor is 1-5 parts.

[0020] The polar hydrophilic groups in the corrosion inhibitor of the present invention can be adsorbed on the metal surface to inhibit corrosion. At the same time, the corrosion inhibitor can be adsorbed in the gaps between the additive molecules, not only filling the gaps, but also increasing the density of the additive. The attraction between molecules will also reduce the distance between molecules, further increasing the adsorption density of the additive molecules on the copper surface, increasing the surface coverage, and enhancing the ability to inhibit corrosion.

[0021] Furthermore, the weight ratio of the additive to the corrosion inhibitor is 2-8:1.

[0022] Furthermore, the weight ratio of the additive to the corrosion inhibitor is preferably 4:1.

[0023] Furthermore, the organic base is one or more of 5-benzyl-[1,3,4]thiadiazol-2-ylamine, 1,3,4-thiadiazol-2-amine and 5-(methoxymethyl)-1,3,4-thiadiazol-2-amine.

[0024] Furthermore, the organic base is preferably 5-benzyl-[1,3,4]thiadiazole-2-ylamine.

[0025] Furthermore, the organic base is 1-8 parts.

[0026] The present invention selects an organic base containing a lone electron pair, whose N and S atoms can provide electrons to copper to form a coordination bond, and the ability to form a coordination bond is greater than the bonding ability of Cu-BTA, thereby removing Cu-BTA. At the same time, the hydrogen atom in -NH2 in the organic base molecule and the oxygen in the sulfonic acid group of the corrosion inhibitor form a hydrogen bond, and the synergistic effect of the π-π conjugation phenomenon between the benzene rings of the two will also form a denser adsorption film, thereby inhibiting corrosion.

[0027] Furthermore, the ultrapure water is deionized water with a resistance greater than or equal to 18 MΩ.

[0028] Another object of the present invention is to disclose a method for preparing a cleaning solution for a semiconductor chip after CMP, comprising the following steps:

[0029] Step 1: Weigh each component in its respective amount;

[0030] Step 2: Add all components except ultrapure water into a container and stir at room temperature until all materials are completely dissolved, and finally add ultrapure water and mix evenly to obtain a semiconductor chip post-CMP cleaning solution.

[0031] Another object of the present invention is to disclose an application of a cleaning liquid for cleaning semiconductor chips after CMP.

[0032] Furthermore, the method for cleaning a semiconductor chip using the semiconductor chip post-CMP cleaning solution comprises the following steps:

[0033] S1: diluting the semiconductor chip post-CMP cleaning solution with ultrapure water by 40-60 times, and then soaking the chip at room temperature for 60-90 seconds to obtain a soaked chip;

[0034] S2: Rinse the soaked chip in ultrapure water to complete chip cleaning.

[0035] Furthermore, in S2, the flushing times are two times or more.

[0036] The semiconductor chip post-CMP cleaning solution of the present invention, its preparation method and application have the following advantages compared with the prior art:

[0037] 1. The present invention adopts a combination of additives and corrosion inhibitors. The hydroxyl group in the additive can be hydrogen bonded with O in the corrosion inhibitor, and the molecules can also be hydrogen bonded to form a large hydrogen bond network. At the same time, the hydroxyl group and the sulfonic acid group have lone electron pairs, which can coordinate with copper ions. The large hydrogen bond network and coordination promote each other, forming a dense adsorption film on the metal surface to inhibit corrosion.

[0038] 2. The present invention adopts a combination of an organic base and a corrosion inhibitor. The π-π conjugated stacking of the aromatic ring in the corrosion inhibitor has an intermolecular electrostatic repulsion effect, and the hydrogen in the organic base -NH2 can form a hydrogen bond with the oxygen of the sulfonic acid group in the corrosion inhibitor. The hydrogen bond and the π-π interaction can increase the adsorption effect by increasing the π electron density and shortening the distance of the aromatic ring. At the same time, the π electrons on the aromatic ring and the amino side chain can accept electrons from the surface of the copper ion to form a feedback bond, which also plays a role in enhancing the adsorption strength of the corrosion inhibitor and the metal surface, forming an adsorption film to inhibit corrosion.

[0039] Therefore, the semiconductor chip post-CMP cleaning solution of the present invention has very good application prospects and large-scale industrial promotion potential in the field of semiconductor chip cleaning. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] Figure 1 This is an optical microscope picture magnified 50 times before the copper chip was cleaned.

[0041] Figure 2 This is an optical microscope picture magnified 50 times after the copper chip was cleaned with the cleaning solution of Example 1.

[0042] Figure 3This is an optical microscope picture magnified 50 times after the copper chip was cleaned with the cleaning solution of Comparative Example 1. DETAILED DESCRIPTION

[0043] The present invention is further described below with reference to the examples. The description of the technical features described below 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:

[0044] Unless otherwise stated, the units used in this specification are all 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.

[0045] In this specification, the numerical range expressed using "a numerical value A to a numerical value B" means a range including the endpoints numerical values ​​A and B.

[0046] In the present specification, a numerical range expressed using "above" or "below" means a numerical range including the number.

[0047] In this specification, the word "may" includes both performing a certain process and not performing a certain process.

[0048] 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.

[0049] In this specification, when "normal temperature" or "room temperature" is used, the temperature may be 15-25°C.

[0050] In this manual, the reagents or instruments used without indicating the manufacturer are all conventional products that can be obtained through commercial purchase.

[0051] Examples 1-6

[0052] Examples 1-6 disclose a variety of semiconductor chip post-CMP cleaning solutions, the components and weight ratios of which are shown in Table 1, and the preparation methods thereof are as follows:

[0053] Step 1: Weigh each component in its respective amount;

[0054] Step 2: Add all components except ultrapure water into a container and stir at 500 rpm at room temperature until all materials are completely dissolved, then add ultrapure water and mix evenly to obtain a semiconductor chip post-CMP cleaning solution.

[0055] Table 1 Components and weight ratios of the cleaning solution for semiconductor chips after CMP in Examples 1-6

[0056]

[0057] Embodiments 1-6 disclose a method of cleaning a semiconductor chip using a plurality of post-CMP cleaning solutions, including the following steps: diluting the post-CMP cleaning solution of the semiconductor chip by 50 times with ultrapure water, and then soaking the chip at room temperature for 80 seconds to obtain a soaked chip; and rinsing the soaked chip in ultrapure water twice to complete the cleaning of the chip.

[0058] Comparative Examples 1-3

[0059] Comparative Examples 1-3 disclose a variety of semiconductor chip cleaning solutions, the components and weight ratios of which are shown in Table 2, and the preparation methods thereof are the same as those of Example 1.

[0060] Table 2 Components and weight ratios of semiconductor chip cleaning solutions in Comparative Examples 1-3

[0061]

[0062] Comparative Examples 1-3 disclose various semiconductor chip post-CMP cleaning solutions for cleaning the chip, and the cleaning method is the same as that of Example 1.

[0063] Metal corrosion tests were performed on the semiconductor chip cleaning solutions of Examples 1-6 and Comparative Examples 1-3, respectively. The test results are shown in Table 3.

[0064] Table 3 Test data

[0065]

[0066] Based on Table 3, it can be seen that the corrosion rates of Examples 1-6 are in the range of 1-2 Å / min, and the corrosion rates of Examples 1-6 are significantly lower than the corrosion rates of Comparative Examples 1-3.

[0067] Specifically, compared with Example 1, Comparative Example 1 did not add a corrosion inhibitor, and due to the lack of the corrosion inhibitor, the chip was severely corroded after cleaning;

[0068] In Comparative Example 2, no additives were added. Due to the lack of additives, the synergistic effect of the corrosion inhibitor and the additive in the components was reduced, the corrosion inhibition effect of the corrosion inhibitor was increased, and corrosion occurred after the chip was cleaned.

[0069] When ammonium hydroxide is used as the organic base in Comparative Example 3, the chip is corroded after cleaning due to the extremely strong alkalinity of ammonium hydroxide.

[0070] Among them: performance test

[0071] Performance Test 1 The test method for metal corrosion is:

[0072] The electrochemical method was used to test the corrosion rate of copper in different cleaning solutions. The specific test method is: use a copper disk electrode (3mm in diameter) as the electrochemical working electrode, platinum as the counter electrode, and a saturated Ag / AgCl electrode as the reference electrode. The cleaning solution of the embodiment and the comparative example was used as the electrolyte solution. The open circuit potential-time (OCP-t) curve and the dynamic potential polarization curve (Tafel) of the working electrode were measured respectively. The corrosion voltage and corrosion current can be obtained by processing the dynamic potential polarization curve using the Tafel extrapolation method. The corrosion rate of copper is calculated using the following formula:

[0073]

[0074] ER: corrosion rate, unit: Å / min;

[0075] M: molar mass, in g / mol;

[0076] I corr : Self-corrosion current, unit A / cm 2 ;

[0077] n: electrochemical reaction charge number;

[0078] F: Faraday constant;

[0079] ρ: density, unit: g / cm 3 .

[0080] Performance Test 2 The test method for cleaning effect is:

[0081] The copper chips before and after the cleaning treatment were tested using an optical microscope, which was magnified 50 times. The test results are as follows: Figure 1-3 .

[0082] Figure 1 This is an optical microscope picture magnified 50 times before the copper chip was cleaned. Figure 2 This is an optical microscope picture magnified 50 times after the copper chip was cleaned with the cleaning solution of Example 1. Figure 3 This is an optical microscope picture magnified 50 times after the copper chip was cleaned with the cleaning solution of Comparative Example 1. It can be seen that there is basically no corrosion when the chip is cleaned with the cleaning solution of Example 1.

[0083] The optical microscope image of the semiconductor chip after cleaning with the post-CMP cleaning solution of Example 2-6 is highly similar to the attached Figure 2 , which are also basically corrosion-free, so they are not listed one by one.

[0084] Figure 3 This is an optical microscope picture after 50 times magnification after cleaning using Comparative Example 1. It can be seen that cleaning the chip using Comparative Example 1 produces corrosion.

[0085] based on Figure 1-3 By comparison, it can be seen that the corrosion inhibitor in the cleaning solution components has a great influence on the corrosion of the chip after cleaning.

[0086] 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 aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned 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 semiconductor chip post-CMP cleaning solution, characterized in that: The composition includes the following components in weight ratio: 1-10 parts of additives; Corrosion inhibitor 1-7 parts; 1-10 parts of organic base; 80-90 parts of ultrapure water; The additive is one or more of N-(9-((1R,3R,4R,7S)-1-((bis(4-methoxyphenyl)(phenyl)methoxy)methyl)-7-hydroxy-2,5-dioxabicyclo[2.2.1]heptane-3-yl)-9H-purin-6-yl)benzamide, 2-hydroxy-3-methoxybenzamide, N-hydroxy-4-methoxy-naphthalene-1-carboxamide, N-hydroxy-5-methoxy-2-pyridinecarboxamide and (Z)-N'-hydroxy-6-methoxypyridinecarboxamide; The corrosion inhibitor is one or more of triethylene glycol di(p-toluenesulfonate), isopropyl ethanesulfonate and isopropyl benzenesulfonate; The weight ratio of the additive to the corrosion inhibitor is 2-8:1; The organic base is one or more of 5-benzyl-[1,3,4]thiadiazol-2-ylamine, 1,3,4-thiadiazol-2-amine and 5-(methoxymethyl)-1,3,4-thiadiazol-2-amine.

2. The semiconductor chip post-CMP cleaning solution according to claim 1, characterized in that: The additive is N-(9-((1R,3R,4R,7S)-1-((bis(4-methoxyphenyl)(phenyl)methoxy)methyl)-7-hydroxy-2,5-dioxabicyclo[2.2.1]heptane-3-yl)-9H-purin-6-yl)benzamide.

3. The semiconductor chip post-CMP cleaning solution according to claim 1, characterized in that: The ultrapure water has a resistance greater than or equal to 18 of deionized water.

4. A method for preparing a semiconductor chip post-CMP cleaning solution according to any one of claims 1 to 3, characterized in that: The following steps are involved: Step 1: Weigh the respective amounts of each component; Step 2: Add all components except ultrapure water into a container and stir at room temperature until all materials are completely dissolved, and finally add ultrapure water and mix evenly to obtain a semiconductor chip post-CMP cleaning solution.

5. Use of the semiconductor chip post-CMP cleaning solution according to any one of claims 1 to 3 in the field of cleaning semiconductor chips.

6. The use according to claim 5, characterized in that: The method for cleaning a semiconductor chip using the semiconductor chip post-CMP cleaning solution comprises the following steps: S1: diluting the semiconductor chip post-CMP cleaning solution with ultrapure water by 40-60 times, and then soaking the chip at room temperature for 60-90 seconds to obtain a soaked chip; S2: Rinse the soaked chip in ultrapure water to complete the chip cleaning.

7. The use according to claim 6, characterized in that: In S2, the number of flushing times is two or more.

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