A hydroxylamine-free organic cleaning agent and its preparation method

Abstract

This invention provides a hydroxylamine-free organic cleaning agent and its preparation method. The organic cleaning agent comprises: dimethyl sulfoxide, 4-hydroxythiomorpholine and its derivatives, catechol, methanol, and the balance water. The preparation method involves first mixing 4-hydroxythiomorpholine and its derivatives with water to obtain solution A; then mixing dimethyl sulfoxide, methanol, and catechol, heating and stirring to obtain solution B; after solution B cools, adding solution A, and stirring until homogeneous to obtain the product. The organic cleaning agent of this invention has high cleaning efficiency, effectively removing residues from the surface of metal pad wafer structures; it exhibits low corrosion rates on aluminum, tungsten, and titanium, without damaging the metal pad wafer structure; and it is hydroxylamine-free, resulting in low production costs, simple usage, no intermediate rinsing process, simplicity and safety, improved cleaning efficiency, and reduced cleaning costs.

Description

Technical Field

[0001] This invention relates to the field of cleaning agents, and more specifically to an organic cleaning agent that does not contain hydroxylamine and its preparation method. Background Technology

[0002] In the manufacturing process of metal pad wafers, cleaning involves hundreds of steps and is a crucial step throughout the entire process, key to improving yield. Chips are highly sensitive to impurities; particles, organic matter, etching residues, and photoresist residues on the surface of the metal pad wafer directly affect product stability and yield. As process nodes advance, the number and importance of cleaning steps continue to increase, leading to higher requirements for cleaning fluid performance. Currently used cleaning agents mainly contain hydroxylamine, which offers good cleaning results but is unsafe, causing pollution to humans and the environment; while hydroxylamine-free cleaning agents generally have limited cleaning effectiveness. Summary of the Invention

[0003] The purpose of this invention is to provide an organic cleaning agent that does not contain hydroxylamine, is simple to prepare, has a low etching rate on metal films, is highly effective at cleaning residues on etched metal pad wafers, and is simple to use with no intermediate rinsing process. It is simple, safe, improves cleaning efficiency, and saves cleaning costs.

[0004] The present invention solves the above problems through the following technical solution: the novel cleaning fluid composition contains: a) Dimethyl sulfoxide; b) 4-Hydroxythiomorpholine and its derivatives; c) catechol; d) Methanol; e) Water; The content of the dimethyl sulfoxide is preferably 30-55%, more preferably 45-55%.

[0005] The 4-hydroxythiomorpholine and its derivatives are selected from one or more of 4-hydroxythiomorpholine, 4-oxide thiomorpholine, 4-hydroxythiomorpholine 1,1-dioxide, 4-hydroxy-3,5-thiomorpholinedione, 4-hydroxy-6-propyl-3-thiomorpholineone, 4-hydroxy-6-phenyl-3-thiomorpholineone, 4-hydroxy-5-phenyl-3-thiomorpholineone, 4-butylthiomorpholine-1,1,4-trioxide, 4-hydroxy-2-phenyl-3,5-thiomorpholinedione, 4-benzylmethylthiomorpholine-1,1,4-trioxide, and 4-hydroxy-5-phenyl-1,1-dioxide-3-thiomorpholineone; the content of the 4-hydroxythiomorpholine and its derivatives is preferably 10-25%, more preferably 15-20%.

[0006] The corrosion inhibitor is catechol, with a preferred content of 1-20%, and more preferably 5-15%.

[0007] The solvent is methanol, with a preferred content of 1-20%, and more preferably 12-18%.

[0008] The remainder is water.

[0009] The cleaning agent of the present invention can be prepared by simply and uniformly mixing the above-mentioned components.

[0010] In this invention, the percentages (%) refer to the mass of each component relative to the total mass of the raw materials, i.e., mass fraction.

[0011] The cleaning agent of this invention can clean the residue after etching at 60°C to 80°C. The specific method is as follows: Immerse the metal pad wafer after dry etching in the cleaning agent of this invention, soak it at 60°C to 80°C for a certain period of time, take it out and clean it with deionized water, and then dry it with high-purity nitrogen.

[0012] The technical effects of this invention are as follows: The cleaning agent of the present invention can efficiently remove dry etching residues on aluminum process metal pad wafers using dimethyl sulfoxide and 4-hydroxythiomorpholine and their derivatives.

[0013] The cleaning agent of the present invention can inhibit the corrosion of metals and other equipment materials through catechol.

[0014] The cleaning agent of this invention does not require an intermediate cleaning process, which greatly improves cleaning efficiency and saves cleaning costs.

[0015] This provides a solution to the problems of expensive, dangerous, and harmful effects of using organic cleaning agents containing hydroxylamine. Detailed Implementation

[0016] The advantages of the cleaning agent of the present invention are illustrated below through specific embodiments, but the scope of protection of the present invention is not limited to the following embodiments.

[0017] All reagents and raw materials used in this invention are commercially available, and the cleaning agent of this invention can be prepared by mixing the above components.

[0018] Table 1. Components and content of the cleaning solution in the examples To better understand the present invention, the following embodiments further illustrate the content of the present invention, but the content of the present invention is not limited to the following embodiments.

[0019] Effect Example To further investigate the cleaning performance of the cleaning agent of the present invention, the following technical means were used: a metal pad wafer after dry etching was subjected to... 1,2,3 Immerse the wafers in the cleaning solution prepared according to the combination in Table 1, and clean them at 60-80°C for 5-20 minutes. After cleaning, rinse them with deionized water at room temperature and then dry them with high-purity nitrogen. The etching rate of the film layer and the cleaning effect on the metal pad wafers are shown in Table 2 below.

[0020] Table 2 shows the cleaning effect of metal pad wafers in some embodiments. As shown in Table 2, the cleaning agent compositions of the embodiments of the present invention have excellent cleaning effects on residues after dry etching on metal pad wafers, and can completely remove the residues. Furthermore, they show almost no etching of titanium nitride (TiN) and thermo-oxidative silicon (Tox) films used in integrated circuits; the etching rates of the embodiments are all less than [a certain value]. / minute; slight etching of metallic aluminum (Al), with corrosion rates less than [value missing] in most embodiments. / minute. The process is simple, with no intermediate rinsing, saving time and operating costs.

[0021] The organic cleaning agent of this invention solves the problems of limited raw material sources and complex usage steps of hydroxylamine cleaning agents, and has good application prospects in fields such as integrated circuit metal pad wafer cleaning.

[0022] In summary, the advantages of this invention are: 1) A composition cleaning agent is provided as an alternative to hydroxylamine organic cleaning agent, which has excellent cleaning effect on etched metal pad wafers.

[0023] 2) It has a relatively low corrosion rate on titanium nitride and thermal oxygen silicon dioxide.

[0024] 3) No intermediate rinsing process, simple and safe, improves cleaning efficiency and saves cleaning costs.

Claims

1. A hydroxylamine-free organic cleaning agent, characterized in that, It contains the following components: (a) Dimethyl sulfoxide, with a mass fraction of 30-55%; (b) A 4-hydroxythiomorpholine derivative, with a mass fraction of 10-25%, wherein the 4-hydroxythiomorpholine derivative is selected from any one of 4-hydroxythiomorpholine-1,1-dioxide, 4-hydroxy-6-propyl-3-thiomorpholineone, 4-hydroxy-5-phenyl-1,1-dioxide-3-thiomorpholineone, and 4-hydroxy-5-phenyl-3-thiomorpholineone; (c) Catechol, mass fraction 1-10%; (d) Methanol, with a mass fraction of 1-20%; (e) The remaining water.

2. The method for preparing a hydroxylamine-free organic cleaning agent according to claim 1, characterized in that, Includes the following steps: Step 1: Mix the 4-hydroxythiomorpholine derivative with water to obtain solution A; Step 2: Mix dimethyl sulfoxide, methanol and catechol, heat to 50°C, and stir for 30 minutes to obtain solution B; Step 3: After solution B cools to room temperature, add solution A and stir for 30 minutes to obtain the product.

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