Low-corrosion semiconductor chip cleaning agent as well as preparation method and application thereof

Abstract

The invention discloses a low-corrosion semiconductor chip cleaning agent as well as a preparation method and application thereof. The low-corrosion semiconductor chip cleaning agent comprises the following components in parts by weight: 1-10 parts of a functional agent, 5-20 parts of a nitrogen-containing organic matter, 1-5 parts of organic alkali and 70-90 parts of ultrapure water. The functional agent is imidazole cyanamide ionic liquid which has double functions of chelating metal ions and dissolving organic pollutants, and an anti-corrosion barrier is formed on the metal surface through pi electrons of an imidazole ring. Nitrogen-containing organic matters cooperate with metal ions through phosphate groups and basic groups and form a hydrogen bond stable system with a functional agent, so that oxidation corrosion is inhibited. The low-corrosion semiconductor chip cleaning agent can efficiently remove metal ions and organic residues under a pure soaking process, and almost does not corrode a chip. The cleaning agent has the characteristics of efficient cleaning and low corrosion, and is suitable for the field of semiconductor chip cleaning.

Description

Technical Field

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

[0002] Semiconductor cleaning is a key step in the semiconductor manufacturing process. Its main purpose is to remove impurities such as particles, natural oxide layers, metal contamination, organic matter, sacrificial layers, polishing residues, etc. on the surface of semiconductor chips to ensure the performance and reliability of the chips. With the continuous advancement of semiconductor technology, the integration of chips and the complexity of manufacturing processes have increased significantly, and the requirements for cleaning equipment and technology have become increasingly stringent.

[0003] The core goal of post-CMP cleaning technology is to efficiently remove polishing slurry residue, abrasive particles, and reaction byproducts from the surface of semiconductor chips while avoiding damage to delicate structures. Due to the varying types and properties of contaminants, the removal process operates in different mechanisms, making the cleaning process challenging.

[0004] The most common contaminants include particles, organic matter, and metals. After polishing, silica sol particles are mostly physically adsorbed on the wafer surface. However, over time, the adsorption of silica sol particles on the wafer surface changes to chemical adsorption, increasing the adsorption heat, desorption difficulties, and cleaning difficulties. In addition, organic matter such as Cu-BTA remaining on the wafer surface decomposes and volatilizes during high-temperature processing, releasing toxic gases and creating pores on the wafer surface. This causes copper ions to diffuse into the dielectric, affecting electromigration and leakage current, and can easily lead to serious problems such as time-dependent dielectric breakdown (TDDB).

[0005] Therefore, the current semiconductor cleaning field urgently needs to develop new cleaning agents and supporting cleaning methods that can efficiently remove contaminants from the chip surface while achieving non-destructive and low-corrosion. Summary of the Invention

[0006] The purpose of the present invention is to propose a low-corrosion semiconductor chip cleaning agent to address the problems of difficulty in desorbing pollutants and cleaning after the CMP process of semiconductor chips. The cleaning agent can effectively remove pollutants on the surface of semiconductor chips, maintain extremely excellent cleaning efficiency under pure immersion process conditions, and cause almost no corrosion to the chips.

[0007] 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.

[0008] To achieve the above object, the technical solution adopted by the present invention is: a low-corrosion semiconductor chip cleaning agent, comprising the following components in the following weight proportions:

[0009]

[0010] The functional agent is an imidazole cyanamide ionic liquid.

[0011] Furthermore, the functional agent is an imidazole dicyanamide ionic liquid.

[0012] Furthermore, the functional agent is one or more of 1-ethyl-3-methylimidazolium dicyanamide salt, 1-butyl-3-methylimidazolium dicyanamide salt and 1-hexyl-3-methylimidazolium dicyanamide salt.

[0013] The functional agent selected by the present invention contains dicyanamide ion N(CN)2 - , can form coordination bonds with metal ions through lone pair electrons, helping to dissolve or stabilize metal pollutants. The nitrogen atom in the imidazole group assists in coordinating the complex metal ion Cu 2+ , and the π electrons of the imidazole ring interact with the metal surface to form a physical barrier, which can inhibit metal corrosion. The functional agent of the present invention removes pollutants on the surface of the semiconductor chip through the dual effects of chelation and inhibition. In addition, the functional agent of the present invention has strong solubility for organic pollutants (Cu-BTA) and can improve the cleaning ability.

[0014] Furthermore, the functional agent is preferably 1-ethyl-3-methylimidazolium dicyanamide salt.

[0015] Furthermore, the functional agent is 2-7 parts.

[0016] Furthermore, the nitrogen-containing organic matter is one or more of β-nicotinamide adenine dinucleotide phosphate sodium salt, flavin adenine dinucleotide disodium salt and 3-acetylpyridinium adenine dinucleotide phosphate sodium salt.

[0017] Furthermore, the nitrogen-containing organic matter is preferably β-nicotinamide adenine dinucleotide phosphate sodium salt.

[0018] Furthermore, the nitrogen-containing organic matter is 7-20 parts.

[0019] The phosphate groups and adenine bases contained in the nitrogen-containing organic matter selected in the present invention can bind to metal ions through electrostatic interaction in an alkaline environment. The phosphate groups can also form hydrogen bonds with the cations of the functional agent, thereby improving the stability of the cleaning agent and providing electrons to inhibit metal oxidation and reduce the oxidative corrosion rate.

[0020] Furthermore, the organic base is an amine organic base and / or a quaternary ammonium base.

[0021] Furthermore, the organic base is one or more of tetrabutylammonium hydroxide, tetraethylammonium hydroxide, N-ethylethylenediamine, tetramethylethylenediamine and N,N-diisopropylethylamine.

[0022] Furthermore, the organic base is preferably tetraethylammonium hydroxide.

[0023] Furthermore, the organic base is 2-4 parts.

[0024] Furthermore, the ultrapure water is 75-85 parts.

[0025] Furthermore, the mass ratio of the functional agent to the nitrogen-containing organic matter is 1:1-5.

[0026] Furthermore, the mass ratio of the functional agent to the nitrogen-containing organic matter is 1:1, 1:1.5, 1:1.8, 1:2, 1:2.8, 1:2.9, 1:3, 1:3.5, 1:4, 1:4.5 or 1:5.

[0027] Furthermore, the preferred mass ratio of the functional agent to the nitrogen-containing organic matter is 1:3.

[0028] Another object of the present invention is to disclose a method for preparing a low-corrosion semiconductor chip cleaning agent, comprising the following steps:

[0029] Step 1: Weigh each component separately;

[0030] Step 2: First, mix and stir the organic base and nitrogen-containing organic matter until they are completely dissolved, then heat to 40-50° C., add the functional agent and ultrapure water while stirring, and continue stirring until the mixture is uniform and transparent to obtain the low-corrosion semiconductor chip cleaning agent.

[0031] Another object of the present invention is to disclose the application of a low-corrosion semiconductor chip cleaning agent in the field of semiconductor chip cleaning.

[0032] Furthermore, the method for cleaning semiconductor chips using the low-corrosion semiconductor chip cleaning agent is as follows:

[0033] S1: diluting a low-corrosion semiconductor chip cleaning agent with ultrapure water, and then soaking a semiconductor chip in the diluted low-corrosion semiconductor chip cleaning agent to obtain a soaked semiconductor chip;

[0034] S2: The semiconductor chip after soaking is placed in ultrapure water for rinsing, thereby completing the cleaning process of the semiconductor chip.

[0035] Furthermore, S1 dilutes the low-corrosion semiconductor chip cleaning agent with ultrapure water to 50-150 times.

[0036] Furthermore, the soaking temperature in S1 is room temperature.

[0037] Furthermore, the soaking time in S1 is 10-30 minutes.

[0038] Furthermore, the flushing times in S2 are two or more.

[0039] The low-corrosion semiconductor chip cleaning agent of the present invention, its preparation method and application have the following advantages compared with the prior art:

[0040] 1) The functional agent imidazole ionic liquid selected in the present invention contains anion part (dicyanamide ion, N(CN)2 - ) can form coordination bonds with metal ions through lone pairs of electrons to help dissolve or stabilize metal pollutants. The nitrogen atom in the imidazolium cation part assists in coordinating the complex metal ion Cu 2+ The dual functions of chelation and inhibition enable the removal of metal ions. Furthermore, the strong solubility of imidazole ionic liquids for organic pollutants enhances cleaning capabilities. Simultaneously, the π electrons of the imidazole ring interact with the metal surface, forming a physical barrier that inhibits metal corrosion.

[0041] 2) The phosphate groups (negatively charged) and adenine bases contained in the nitrogen-containing organic matter selected in the present invention can bind to metal ions through electrostatic interaction in an alkaline environment. The phosphate groups can also form hydrogen bonds with the cations of the functional agent, thereby improving the stability of the system, reducing component decomposition, and providing electrons to inhibit metal oxidation and reduce the rate of oxidative corrosion.

[0042] 3) The present invention adopts a combination of a functional agent and a nitrogen-containing organic compound. The phosphate group of the nitrogen-containing organic compound forms a hydrogen bond with the cation of the functional agent. The two combine to form a stable cleaning agent, which avoids secondary deposition, improves the chip cleaning yield, and at the same time enhances the complexing ability and inhibits corrosion.

[0043] The low-corrosion semiconductor chip cleaning agent of the present invention has good application prospects and large-scale promotion potential in the field of semiconductor chip cleaning. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] Attachment Figure 1 This is a microscope picture of a semiconductor chip before cleaning at 500 times magnification;

[0045] Attachment Figure 2 This is a microscope picture magnified 500 times of a semiconductor chip after cleaning using the cleaning agent prepared in Example 1;

[0046] Attachment Figure 3 This is a microscope picture magnified 500 times of a semiconductor chip after cleaning using the cleaning agent prepared in Comparative Example 1. DETAILED DESCRIPTION

[0047] 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:

[0048] 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.

[0049] 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.

[0050] In this specification, the numerical range expressed using "above" or "below" means a numerical range including the number.

[0051] 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.

[0052] 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.

[0053] In this specification, when "normal temperature" or "room temperature" is used, the temperature may be 15-25°C.

[0054] In this manual, the reagents or instruments used without indicating the manufacturer are all conventional products that can be obtained through commercial purchase.

[0055] Examples 1-5

[0056] Examples 1-5 disclose a variety of low-corrosion semiconductor chip cleaning agents, the components and proportions of which are shown in Table 1. The preparation methods are as follows:

[0057] Step 1: Weigh each component separately;

[0058] Step 2: First, mix the organic base and the nitrogen-containing organic matter and stir until all the materials are completely dissolved, then heat to 50° C., add the functional agent and ultrapure water while stirring, and continue stirring until uniform and transparent to obtain the low-corrosion semiconductor chip cleaning agent.

[0059] Table 1 Composition and ratio of Examples 1-5

[0060]

[0061]

[0062] Comparative Examples 1-5

[0063] Comparative Examples 1-5 disclose a variety of cleaning agents, the components and proportions of which are shown in Table 2, and the preparation methods thereof are the same as those of Example 1.

[0064] Table 2 Components and ratios of Comparative Examples 1-5

[0065]

[0066] The cleaning agents of Examples 1-5 and Comparative Examples 1-5 were tested respectively, and the test methods and test results are as follows:

[0067] Table 3 Test results

[0068]

[0069] As can be seen from Table 3, all embodiments of the present invention can achieve no residue and a low corrosion rate for Cu; while in Comparative Example 1, due to the lack of the addition of a functional agent, cleaning residues are present and the corrosion rate is as high as It proves that the chelation effect and corrosion inhibition of functional agents are irreplaceable.

[0070] Comparative Example 2 uses hexafluorophosphate ionic liquid as a functional agent. Due to the lack of the effect of dicyanamide groups, the corrosion rate increases to Description of specific anions (N(CN)2 - )'s coordination ability is crucial to inhibit corrosion.

[0071] Comparative Example 3 did not add nitrogen-containing organic matter, resulting in a corrosion rate of Moreover, there are residues after cleaning, indicating that nitrogen-containing organic matter plays an indispensable role in stabilizing the system and inhibiting oxidative corrosion through phosphate groups.

[0072] Comparative Example 4 uses rosin polyethylene glycol citrate to replace nitrogen-containing organic matter, and the corrosion rate is It is proved that the electrostatic binding ability of nitrogenous base (adenine) to metal ions is the core function of nitrogenous organic matter.

[0073] Comparative Example 5 uses unphosphorylated β-nicotinamide adenine dinucleotide as the nitrogen-containing organic matter. Due to the lack of the effect of the phosphate group, the corrosion rate increases to It is proved that the phosphate group plays a key role in enhancing the stability of the detergent and inhibiting metal oxidation.

[0074] In summary, it can be seen that the corrosion rates of all comparative examples are increased, proving that the synergistic effect of the functional agent of the present invention and the nitrogen-containing organic compound is a key component for effectively removing pollutants on the surface of semiconductor chips and reducing corrosion of semiconductor chips.

[0075] Although comparative examples 4 and 5 can achieve residue-free cleaning, their corrosion inhibition capabilities are insufficient, which illustrates the irreplaceable nature of the specific structure of the components in the present invention.

[0076] Further explanation is provided by the accompanying drawings:

[0077] Attachment Figure 1 This is a microscope picture of the semiconductor chip before cleaning magnified 500 times; Figure 2 is a microscope picture of a semiconductor chip after cleaning with the cleaning agent prepared in Example 1, magnified 500 times; Figure 3 This is a microscope picture of a semiconductor chip magnified 500 times after cleaning with the cleaning agent prepared in Comparative Example 1. Figure 1-3 It can be seen that Figure 2 The chip is cleaned with the cleaning solution of Example 1 with essentially no corrosion. Figure 3 After cleaning with the cleaning solution of Comparative Example 1, the chip was corroded.

[0078] in:

[0079] The test method for performance 1 cleaning effect is:

[0080] After the semiconductor chip undergoes the grinding and polishing steps in the back-end process, a large amount of wax, polishing powder residue, polishing liquid residue, etc. remain on the chip. The cleaning agent of the above embodiment and comparative example of the present invention is used to clean the chip. The cleaning method includes the following steps:

[0081] Step 1: diluting the low-corrosion semiconductor chip cleaning agent by 50 times with ultrapure water, and then using the aqueous solution to soak the semiconductor chip at room temperature of 25° C. for 10 minutes to obtain a soaked chip;

[0082] Step 2: Rinse the soaked chip twice in ultrapure water, and then blow dry the chip with nitrogen gas, thus completing the chip cleaning process.

[0083] The ultrapure water used in steps 1 and 2 is deionized water with a resistance of at least 18 MΩ.

[0084] The test method for performance 2 metal corrosion is:

[0085] ICP-MS (Inductively Coupled Plasma Mass Spectrometry) was used to test the corrosion performance of different cleaning agents on metals. The specific test method was as follows: 2 The Cu sheet was immersed in the cleaning agent at room temperature for 1 hour, and then the metal ion concentration in the cleaning agent was measured by ICP-MS method, and the corrosion rate was calculated. Right now / minute, also known as "etching rate"), thereby examining the corrosion rate of metals by different cleaning agents.

[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 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 low-corrosion semiconductor chip cleaning agent, characterized in that: The composition comprises the following components in the following weight ratios: The functional agent is an imidazole cyanamide ionic liquid.

2. The low-corrosion semiconductor chip cleaning agent according to claim 1, characterized in that: The functional agent is one or more of 1-ethyl-3-methylimidazolium dicyanamide salt, 1-butyl-3-methylimidazolium dicyanamide salt and 1-hexyl-3-methylimidazolium dicyanamide salt.

3. The low-corrosion semiconductor chip cleaning agent according to claim 1, characterized in that: The nitrogen-containing organic matter is one or more of β-nicotinamide adenine dinucleotide phosphate sodium salt, flavin adenine dinucleotide disodium salt and 3-acetylpyridine adenine dinucleotide phosphate sodium salt.

4. The low-corrosion semiconductor chip cleaning agent according to claim 1, characterized in that: The organic base is an amine organic base and / or a quaternary ammonium base.

5. The low-corrosion semiconductor chip cleaning agent according to claim 1 or 4, characterized in that: The organic base is one or more of tetrabutylammonium hydroxide, tetraethylammonium hydroxide, N-ethylethylenediamine, tetramethylethylenediamine and N,N-diisopropylethylamine.

6. The low-corrosion semiconductor chip cleaning agent according to claim 1, characterized in that: The mass ratio of the functional agent to the nitrogen-containing organic matter is 1:1-5.

7. A method for preparing the low-corrosion semiconductor chip cleaning agent according to any one of claims 1 to 6, characterized in that: The following steps are involved: Step 1: Weigh each component separately; Step 2: First, mix and stir the organic base and nitrogen-containing organic matter until they are completely dissolved, then heat to 40-50° C., add the functional agent and ultrapure water while stirring, and continue stirring until the mixture is uniform and transparent to obtain the low-corrosion semiconductor chip cleaning agent.

8. Use of the low-corrosion semiconductor chip cleaning agent according to any one of claims 1 to 6 in the field of semiconductor chip cleaning.

9. The use of the low-corrosion semiconductor chip cleaning agent according to claim 8, characterized in that: The method for cleaning semiconductor chips using the low-corrosion semiconductor chip cleaning agent is as follows: S1: diluting a low-corrosion semiconductor chip cleaning agent with ultrapure water, and then soaking a semiconductor chip in the diluted low-corrosion semiconductor chip cleaning agent to obtain a soaked semiconductor chip; S2: The semiconductor chip after soaking is placed in ultrapure water for rinsing, thereby completing the cleaning process of the semiconductor chip.

10. The use of the low-corrosion semiconductor chip cleaning agent according to claim 9, characterized in that: S1 dilute the low-corrosion semiconductor chip cleaning agent with ultrapure water to 50-150 times.

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