Silicon oxide thinning liquid for integrated circuit and preparation method thereof

Abstract

The present invention proposes a silicon oxide thinning liquid for integrated circuits and a preparation method thereof, belonging to the technical field of integrated circuits. The silicon oxide thinning liquid is prepared from the following raw materials by weight: 5-10 parts of polyvinyl alcohol quaternary ammonium salt stabilizer, 10-20 parts of hydrofluoric acid, 5-10 parts of sulfuric acid, 5-10 parts of nitric acid, 3-5 parts of surfactant and 50-90 parts of water. The utilization rate of the silicon oxide thinning liquid for integrated circuits of the present invention is improved, the amount of waste liquid generated is significantly reduced, the treatment is simple, and the preparation method is simple, safe and environmentally friendly, and the work efficiency is high, and it has broad application prospects.

Description

Technical Field

[0001] The present invention relates to the technical field of integrated circuits, and in particular to a silicon oxide thinning liquid for integrated circuits and a preparation method thereof. Background Art

[0002] With the development of electronic technology and display technology, the thinning of glass substrates as the core of display product thinning has become the premise and driving force of terminal display product thinning. At present, the thinning technology of glass substrates for display products, or its thinning technology, mainly includes physical grinding and polishing thinning and chemical etching thinning. Chemical etching thinning is gradually becoming the mainstream technology for glass substrate thinning with its technical advantages such as fast speed, high efficiency and low investment. Taking the production of TFT-LCD (thin film transistor liquid crystal display) as an example, the current mainstream thickness of the original glass substrate is 0.5mm, which is also the thinnest thickness that can be achieved by the current TFT-LCD array substrate production process. It does not meet the requirements of terminal display product thinning, which also shows the value of glass substrate thinning technology. For the process technology of thinning a 0.5mm (1.0mm on both sides after boxing) thick glass substrate to 0.25mm (0.5mm on both sides after boxing) or even thinner, the advantages of chemical etching thinning are obvious compared with physical grinding thinning. The existing chemical etching thinning technology mostly uses a single hydrofluoric acid as an etching solution for thinning, but this etching solution has the following disadvantages:

[0003] 1. Highly toxic and volatile. During the production process, especially during preparation, high temperature conditions and hydrofluoric acid concentrations are required, which easily volatilizes a large amount of hydrofluoric acid gas, which is highly toxic and dangerous.

[0004] 2. The etching rate of the etching solution during the production process is unstable and the utilization rate is low.

[0005] 3. Due to the low utilization rate of etching liquid, the waste liquid treatment volume is large and difficult to handle, and the corresponding waste liquid treatment cost is high.

[0006] 4. The product is difficult to remove. Hydrofluoric acid reacts with glass to generate a large amount of white insoluble products, which are not only difficult to remove from the glass surface, but will also further adhere to the equipment and pipelines, resulting in poor product surface effects, pipeline blockage, equipment shutdown, and even safety accidents. Summary of the invention

[0007] The purpose of the present invention is to provide a silicon oxide thinning liquid for integrated circuits and a preparation method thereof, which improves the utilization rate, significantly reduces the amount of waste liquid generated, is simple to handle, and has a simple preparation method, safety, environmental protection, high work efficiency, and broad application prospects.

[0008] The technical solution of the present invention is achieved in this way:

[0009] The invention provides a silicon oxide thinning liquid for integrated circuits, comprising the following raw materials: a polyvinyl alcohol quaternary ammonium salt stabilizer, hydrofluoric acid, sulfuric acid, nitric acid, a surfactant and water.

[0010] As a further improvement of the present invention, the present invention is prepared from the following raw materials in parts by weight: 5-10 parts of polyvinyl alcohol quaternary ammonium salt stabilizer, 10-20 parts of hydrofluoric acid, 5-10 parts of sulfuric acid, 5-10 parts of nitric acid, 3-5 parts of surfactant and 50-90 parts of water.

[0011] As a further improvement of the present invention, the sulfuric acid is concentrated sulfuric acid with a concentration greater than 98%.

[0012] As a further improvement of the present invention, the surfactant is selected from at least one of sodium dodecylbenzene sulfonate, sodium dodecyl sulfonate, sodium dodecyl sulfate, sodium tetradecyl sulfide, sodium tetradecyl sulfonate, sodium tetradecylbenzene sulfonate, sodium hexadecylbenzene sulfonate, sodium hexadecyl sulfonate, sodium hexadecyl sulfate, sodium octadecyl sulfonate, sodium octadecylbenzene sulfonate, and sodium octadecyl sulfate.

[0013] As a further improvement of the present invention, the preparation method of the polyvinyl alcohol quaternary ammonium salt stabilizer is as follows:

[0014] S1. dissolving polyvinyl alcohol in an aqueous solution to obtain a polyvinyl alcohol solution;

[0015] S2. The polyvinyl alcohol solution obtained in step S1, dimethylaminoethyl methacrylate and an initiator are mixed, heated and stirred to react, ethanol is added to precipitate, filtered, and washed to obtain modified polyvinyl alcohol;

[0016] S3. Add the modified polyvinyl alcohol obtained in step S2 to an organic solvent, add alkali and epichlorohydrin, heat and stir to react, add water to precipitate, filter, wash, and dry to obtain a polyvinyl alcohol quaternary ammonium salt stabilizer.

[0017] As a further improvement of the present invention, the content of the polyvinyl alcohol solution in step S1 is 30-40wt%.

[0018] As a further improvement of the present invention, the mass ratio of the polyvinyl alcohol solution, dimethylaminoethyl methacrylate and the initiator in step S2 is 100:10-12:0.5-1; the initiator is selected from at least one of sodium persulfate, potassium persulfate and ammonium persulfate; the temperature of the heating and stirring reaction is 60-70°C and the time is 1-2h.

[0019] As a further improvement of the present invention, the organic solvent in step S3 is selected from at least one of dichloromethane, chloroform, ethyl acetate, methyl acetate, butyl acetate, petroleum ether, cyclohexane, and n-hexane; the base is selected from at least one of triethylamine, diethylamine, NaOH, and KOH; the mass ratio of the modified polyvinyl alcohol, the base, and epichlorohydrin is 10:2-3:2-4; the temperature of the stirring reaction is 40-60°C, and the time is 2-3h.

[0020] As a further improvement of the present invention, the preparation method of the polyvinyl alcohol quaternary ammonium salt stabilizer is as follows:

[0021] S1. dissolving polyvinyl alcohol in an aqueous solution to obtain a 30-40wt% polyvinyl alcohol solution;

[0022] S2. 100 parts by weight of the polyvinyl alcohol solution obtained in step S1, 10-12 parts by weight of dimethylaminoethyl methacrylate and 0.5-1 parts by weight of an initiator are mixed, heated to 60-70 ° C, stirred for 1-2h, an equal volume of ethanol is added to precipitate, filtered, and washed to obtain a modified polyvinyl alcohol;

[0023] S3. Add 10 parts by weight of the modified polyvinyl alcohol obtained in step S2 to 50 parts by weight of an organic solvent, add 2-3 parts by weight of a base and 2-4 parts by weight of epichlorohydrin, heat to 40-60°C, stir the reaction for 2-3h, add an equal volume of water to precipitate, filter, wash, and dry to obtain a polyvinyl alcohol quaternary ammonium salt stabilizer.

[0024] The present invention further protects a method for preparing the above-mentioned silicon oxide thinning liquid for integrated circuits, comprising the following steps: stirring and mixing hydrofluoric acid, sulfuric acid, nitric acid, a surfactant and water evenly, adding a polyvinyl alcohol quaternary ammonium salt stabilizer, stirring and mixing, and preparing the silicon oxide thinning liquid for integrated circuits.

[0025] The present invention has the following beneficial effects: the silicon oxide thinning liquid for integrated circuits of the present invention can fix hydrofluoric acid and nitric acid by forming a macromolecular gel by adding a polyvinyl alcohol quaternary ammonium salt stabilizer, thereby effectively avoiding the high-temperature volatilization of hydrofluoric acid and nitric acid and reducing their pollution to the environment. At the same time, a high concentration of hydrofluoric acid is maintained, thereby greatly increasing the working efficiency of the thinning liquid.

[0026] The polyvinyl alcohol quaternary ammonium salt stabilizer of the present invention contains a long-chain quaternary ammonium salt structure, which can not only stabilize hydrofluoric acid but also further reduce the surface tension of the thinning liquid and improve its etching effect.

[0027] The present invention adopts less toxic acids to cooperate with hydrofluoric acid to work, so that the concentration and dosage of hydrofluoric acid are greatly reduced, and the toxicity and volatility of acids such as sulfuric acid and nitric acid are much smaller than that of hydrofluoric acid, which significantly improves the safety and environmental protection of the etching solution.

[0028] The utilization rate of the silicon oxide thinning liquid for integrated circuits of the present invention is improved, the amount of waste liquid generated is significantly reduced, the treatment is simple, and the preparation method is simple, safe and environmentally friendly, with high working efficiency, and has broad application prospects. DETAILED DESCRIPTION

[0029] The technical solutions in the embodiments of the present invention are described clearly and completely below. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0030] Example 1

[0031] Raw material composition (parts by weight): 5 parts of polyvinyl alcohol quaternary ammonium salt stabilizer, 10 parts of hydrofluoric acid, 5 parts of 98% concentrated sulfuric acid, 5 parts of nitric acid, 3 parts of sodium octadecylbenzene sulfonate and 50 parts of water.

[0032] The preparation method of the polyvinyl alcohol quaternary ammonium salt stabilizer is as follows:

[0033] S1. dissolving polyvinyl alcohol in an aqueous solution to obtain a 30wt% polyvinyl alcohol solution;

[0034] S2. 100 parts by weight of the polyvinyl alcohol solution obtained in step S1, 10 parts by weight of dimethylaminoethyl methacrylate and 0.5 parts by weight of potassium persulfate were mixed, heated to 60 ° C, stirred for 1 h, an equal volume of ethanol was added to precipitate, filtered, and washed to obtain modified polyvinyl alcohol;

[0035] S3. Add 10 parts by weight of the modified polyvinyl alcohol obtained in step S2 to 50 parts by weight of petroleum ether, add 2 parts by weight of NaOH and 2 parts by weight of epichlorohydrin, heat to 40°C, stir the reaction for 2h, add an equal volume of water to precipitate, filter, wash, and dry to obtain a polyvinyl alcohol quaternary ammonium salt stabilizer.

[0036] A method for preparing silicon oxide thinning liquid for integrated circuits comprises the following steps: mixing hydrofluoric acid, 98% concentrated sulfuric acid, nitric acid, sodium octadecylbenzene sulfonate and water evenly, adding polyvinyl alcohol quaternary ammonium salt stabilizer, stirring and mixing, and preparing silicon oxide thinning liquid for integrated circuits.

[0037] Example 2

[0038] Raw material composition (parts by weight): 10 parts of polyvinyl alcohol quaternary ammonium salt stabilizer, 20 parts of hydrofluoric acid, 10 parts of 98% concentrated sulfuric acid, 10 parts of nitric acid, 5 parts of sodium hexadecylbenzene sulfonate and 90 parts of water.

[0039] The preparation method of the polyvinyl alcohol quaternary ammonium salt stabilizer is as follows:

[0040] S1. dissolving polyvinyl alcohol in an aqueous solution to obtain a 40wt% polyvinyl alcohol solution;

[0041] S2. 100 parts by weight of the polyvinyl alcohol solution obtained in step S1, 12 parts by weight of dimethylaminoethyl methacrylate and 1 part by weight of sodium persulfate were mixed, heated to 70 ° C, stirred for 2 h, an equal volume of ethanol was added to precipitate, filtered, and washed to obtain modified polyvinyl alcohol;

[0042] S3. Add 10 parts by weight of the modified polyvinyl alcohol obtained in step S2 to 50 parts by weight of ethyl acetate, add 3 parts by weight of triethylamine and 4 parts by weight of epichlorohydrin, heat to 60°C, stir the reaction for 3 hours, add an equal volume of water to precipitate, filter, wash, and dry to obtain a polyvinyl alcohol quaternary ammonium salt stabilizer.

[0043] A method for preparing silicon oxide thinning liquid for integrated circuits comprises the following steps: mixing hydrofluoric acid, 98% concentrated sulfuric acid, nitric acid, sodium hexadecylbenzene sulfonate and water evenly, adding polyvinyl alcohol quaternary ammonium salt stabilizer, stirring and mixing, and preparing silicon oxide thinning liquid for integrated circuits.

[0044] Example 3

[0045] Raw material composition (parts by weight): 7 parts of polyvinyl alcohol quaternary ammonium salt stabilizer, 15 parts of hydrofluoric acid, 7 parts of 98% concentrated sulfuric acid, 7 parts of nitric acid, 4 parts of sodium dodecyl sulfate and 70 parts of water.

[0046] The preparation method of the polyvinyl alcohol quaternary ammonium salt stabilizer is as follows:

[0047] S1. dissolving polyvinyl alcohol in an aqueous solution to obtain a 35wt% polyvinyl alcohol solution;

[0048] S2. 100 parts by weight of the polyvinyl alcohol solution obtained in step S1, 11 parts by weight of dimethylaminoethyl methacrylate and 0.7 parts by weight of ammonium persulfate were mixed, heated to 65 ° C, stirred for 1.5 h, an equal volume of ethanol was added to precipitate, filtered, and washed to obtain modified polyvinyl alcohol;

[0049] S3. Add 10 parts by weight of the modified polyvinyl alcohol obtained in step S2 to 50 parts by weight of dichloromethane, add 2.5 parts by weight of KOH and 3 parts by weight of epichlorohydrin, heat to 50°C, stir the reaction for 2.5h, add an equal volume of water to precipitate, filter, wash, and dry to obtain a polyvinyl alcohol quaternary ammonium salt stabilizer.

[0050] A method for preparing silicon oxide thinning liquid for integrated circuits comprises the following steps: mixing hydrofluoric acid, 98% concentrated sulfuric acid, nitric acid, sodium dodecyl sulfate and water evenly, adding polyvinyl alcohol quaternary ammonium salt stabilizer, mixing and preparing silicon oxide thinning liquid for integrated circuits.

[0051] Comparative Example 1

[0052] Compared with Example 3, the difference is that step S2 is not performed during the preparation of the polyvinyl alcohol quaternary ammonium salt stabilizer.

[0053] Raw material composition (parts by weight): 7 parts of polyvinyl alcohol quaternary ammonium salt stabilizer, 15 parts of hydrofluoric acid, 7 parts of 98% concentrated sulfuric acid, 7 parts of nitric acid, 4 parts of sodium dodecyl sulfate and 70 parts of water.

[0054] The preparation method of the polyvinyl alcohol quaternary ammonium salt stabilizer is as follows:

[0055] S1. dissolving polyvinyl alcohol in an aqueous solution to obtain a 35wt% polyvinyl alcohol solution;

[0056] S2. Add 10 parts by weight of the modified polyvinyl alcohol obtained in step S1 to 50 parts by weight of dichloromethane, add 2.5 parts by weight of KOH and 3 parts by weight of epichlorohydrin, heat to 50°C, stir the reaction for 2.5 hours, add an equal volume of water to precipitate, filter, wash, and dry to obtain a polyvinyl alcohol quaternary ammonium salt stabilizer.

[0057] A method for preparing silicon oxide thinning liquid for integrated circuits comprises the following steps: mixing hydrofluoric acid, 98% concentrated sulfuric acid, nitric acid, sodium dodecyl sulfate and water evenly, adding polyvinyl alcohol quaternary ammonium salt stabilizer, mixing and preparing silicon oxide thinning liquid for integrated circuits.

[0058] Comparative Example 2

[0059] Compared with Example 3, the difference is that steps S2 and S3 are not performed in the preparation process of the polyvinyl alcohol quaternary ammonium salt stabilizer.

[0060] Raw material composition (parts by weight): 7 parts of polyvinyl alcohol quaternary ammonium salt stabilizer, 15 parts of hydrofluoric acid, 7 parts of 98% concentrated sulfuric acid, 7 parts of nitric acid, 4 parts of sodium dodecyl sulfate and 70 parts of water.

[0061] The preparation method of the polyvinyl alcohol quaternary ammonium salt stabilizer is as follows: polyvinyl alcohol is dissolved in an aqueous solution to obtain a 35 wt % polyvinyl alcohol solution.

[0062] A method for preparing silicon oxide thinning liquid for integrated circuits comprises the following steps: mixing hydrofluoric acid, 98% concentrated sulfuric acid, nitric acid, sodium dodecyl sulfate and water evenly, adding polyvinyl alcohol quaternary ammonium salt stabilizer, mixing and preparing silicon oxide thinning liquid for integrated circuits.

[0063] Test Example 1

[0064] The integrated circuits prepared in Examples 1-3 of the present invention and Comparative Examples 1-2 were subjected to performance tests using silicon oxide thinning liquid. The results are shown in Table 1.

[0065] Table 1

[0066] Group Thinning fluid utilization rate (%) Thickness uniformity after thinning (%) Thinning rate (μm / min) Example 1 35 1.02 22 Example 2 37 1.08 24 Example 3 40 0.99 25 Comparative Example 1 25 2.54 12 Comparative Example 2 18 3.14 6

[0067] It can be seen from the above table that the silicon oxide thinning liquid for integrated circuits prepared in Examples 1-3 of the present invention has a fast thinning rate, high thickness uniformity after thinning, and high thinning liquid utilization rate.

[0068] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A silicon oxide thinning liquid for integrated circuits, characterized in that: The method is prepared from the following raw materials by weight: 5-10 parts of polyvinyl alcohol quaternary ammonium salt stabilizer, 10-20 parts of hydrofluoric acid, 5-10 parts of sulfuric acid, 5-10 parts of nitric acid, 3-5 parts of surfactant and 50-90 parts of water; The sulfuric acid is concentrated sulfuric acid with a concentration greater than 98%; The surfactant is selected from at least one of sodium dodecylbenzene sulfonate, sodium dodecyl sulfonate, sodium dodecyl sulfate, sodium tetradecyl sulfide, sodium tetradecyl sulfonate, sodium tetradecylbenzene sulfonate, sodium hexadecylbenzene sulfonate, sodium hexadecyl sulfonate, sodium hexadecyl sulfate, sodium octadecyl sulfonate, sodium octadecylbenzene sulfonate, and sodium octadecyl sulfate; The preparation method of the polyvinyl alcohol quaternary ammonium salt stabilizer is as follows: S1. Dissolving polyvinyl alcohol in an aqueous solution to obtain a 30-40wt% polyvinyl alcohol solution; S2. 100 parts by weight of the polyvinyl alcohol solution obtained in step S1, 10-12 parts by weight of dimethylaminoethyl methacrylate and 0.5-1 parts by weight of an initiator are mixed, heated to 60-70 ° C, stirred for 1-2h, an equal volume of ethanol is added to precipitate, filtered, and washed to obtain a modified polyvinyl alcohol; S3. 10 parts by weight of the modified polyvinyl alcohol obtained in step S2 was added to 50 parts by weight of an organic solvent, 2-3 parts by weight of a base and 2-4 parts by weight of epichlorohydrin were added, heated to 40-60 ° C, stirred for 2-3h, an equal volume of water was added to precipitate, filtered, washed and dried to obtain a polyvinyl alcohol quaternary ammonium stabilizer; The initiator is selected from at least one of sodium persulfate, potassium persulfate and ammonium persulfate; The organic solvent is selected from at least one of dichloromethane, chloroform, ethyl acetate, methyl acetate, butyl acetate, petroleum ether, cyclohexane, and n-hexane; The base is selected from at least one of triethylamine, diethylamine, NaOH and KOH.

2. A method for preparing a silicon oxide thinning liquid for integrated circuits as claimed in claim 1, characterized in that: The method comprises the following steps: mixing hydrofluoric acid, sulfuric acid, nitric acid, a surfactant and water evenly, adding a polyvinyl alcohol quaternary ammonium salt stabilizer, mixing and stirring to prepare a silicon oxide thinning liquid for integrated circuits.