CN111378370B

CN111378370B - Chemical mechanical polishing solution

Info

Publication number: CN111378370B
Application number: CN201811627087.XA
Authority: CN
Inventors: 何华锋; 王晨; 李星; 史经深
Original assignee: Anji Microelectronics Shanghai Co Ltd
Current assignee: Anji Microelectronics Shanghai Co Ltd
Priority date: 2018-12-28
Filing date: 2018-12-28
Publication date: 2022-05-13
Anticipated expiration: 2038-12-28
Also published as: CN111378370A

Abstract

The invention provides a chemical mechanical polishing solution which comprises silicon dioxide abrasive particles, a polishing rate accelerator, a pH regulator, an oxidation-resistant discoloring agent and water. The chemical mechanical polishing solution disclosed by the invention reduces the consumption of the polishing rate accelerator by using the oxidation-resistant discoloring agent in the polishing solution, thereby reducing byproducts generated by the consumption of the polishing rate accelerator in the use of the polishing solution, enabling the polishing solution not to generate color change for a long time in the cyclic use of the polishing solution, and improving the stability and the cyclic utilization rate of the polishing solution.

Description

Chemical mechanical polishing solution

Technical Field

The invention relates to the field of chemical mechanical polishing, in particular to a chemical mechanical polishing solution.

Background

Currently, with the continuous development of semiconductor technology and the continuous increase of interconnect layers of large-scale integrated circuits, the planarization technology of the conductive layer and the insulating dielectric layer becomes more critical. While Chemical Mechanical Polishing (CMP) techniques are considered to be the most effective method of global planarization at present.

Chemical Mechanical Polishing (CMP) consists of chemical action, mechanical action, and a combination of these two actions. It generally consists of a polishing table with a polishing pad and a polishing head for carrying the chip. Wherein the polishing head holds the chip and then presses the front side of the chip against the polishing pad. When performing chemical mechanical polishing, the polishing head moves linearly over the polishing pad or rotates in the same direction of motion as the polishing table. At the same time, the slurry containing the abrasive particles is dropped onto the polishing pad and is spread on the polishing pad by centrifugation. The chip surface is globally planarized under the dual actions of mechanical and chemical.

The main material used in the chemical mechanical polishing process is polishing solution. In order to reduce the cost, manufacturers generally dilute the polishing solution several times according to the property of the polishing solution and recycle the polishing solution, and during the polishing process, whether to replace the polishing solution is determined according to the polishing rate and the surface quality of the silicon wafer. Therefore, the use amount of the polishing solution can be reduced, and the cost is greatly reduced. However, in the process of recycling the polishing solution, the polishing solution changes its shape with the consumption of the polishing accelerator and the change of the chemical and physical properties of the polishing accelerator, resulting in color change and gradual accumulation of polishing by-products, which results in the performance of the polishing solution being lowered, failing to exert its original effect, and even blocking the pipeline in serious cases, resulting in the surface of the wafer being scratched and the yield of the product being lowered.

Disclosure of Invention

In order to solve the above problems, the present invention provides a chemical mechanical polishing solution, in which an oxidation-resistant discoloring agent is used in the polishing solution, so that the consumption of a polishing rate accelerator is reduced, and the stability and the cyclic utilization rate of the polishing solution are improved.

Specifically, the invention provides a chemical mechanical polishing solution, which comprises silicon dioxide abrasive particles, a polishing rate accelerator, a pH regulator, an oxidation-resistant discoloring agent and water.

Preferably, the content of the silica abrasive particles is 0.1-40% by mass.

Preferably, the content of the silica abrasive particles is 15-30% by mass.

Preferably, the polishing rate accelerator comprises one or more of piperazine, monoethanolamine, and diethylenetriamine.

Preferably, the polishing rate accelerator is contained in an amount of 0.1 to 20% by mass.

Preferably, the anti-oxidative discoloration agent comprises one or more of benzotriazole, 1,2, 3-triazole, benzimidazole, 5-phenyl-1H-tetrazole, ascorbic acid, tea polyphenol, uric acid, cyanuric acid, barbituric acid, glucuronic acid, squaric acid, adenosine, purine, nicotinamide, flavonol, and anthocyanin.

Preferably, the content of the antioxidant discoloration agent is 0.0001-1% by mass.

Preferably, the pH adjusting agent comprises one or more of KOH, nitric acid, tetramethylammonium hydroxide.

Preferably, the pH value of the chemical mechanical polishing solution is 10-12. Compared with the prior art, the invention has the advantages that: the consumption of the polishing rate accelerator is reduced by using the oxidation-resistant discoloring agent in the polishing solution, so that by-products generated by the consumption of the polishing rate accelerator in the use of the polishing solution are reduced, the polishing solution does not have color change for a long time in the cyclic use, and the stability and the cyclic utilization rate of the polishing solution are improved. In addition, the polishing solution can be prepared by mixing the components to obtain a highly concentrated polishing solution, and water is used for supplementing the mass percent to 100 percent when the polishing solution is used, so that the polishing solution is more convenient to transport and store.

Detailed Description

The advantages of the present invention are further illustrated by the following specific examples, but the scope of the present invention is not limited to the following examples.

Table 1 shows the components and contents of the polishing solutions of examples 1 to 17 of the present invention and comparative examples 1 to 3. Preparing polishing solutions of examples and comparative examples according to the table, uniformly mixing the components, complementing the mass percent to 100% with water, and adjusting the pH value to a required value by using KOH, tetramethylammonium hydroxide or nitric acid to obtain the polishing solutions of the examples and the comparative examples.

TABLE 1 polishing slurry compositions of inventive examples 1-17 and comparative examples 1-3

Silicon wafers were polished with the chemical mechanical polishing liquids of examples 1 to 17 and comparative examples 1 to 3, respectively. The polishing liquids of the examples and comparative examples were recycled during polishing, and the time from the start of polishing to the occurrence of color change of the polishing liquid was recorded, thereby obtaining the time during which the color of the polishing liquid remained unchanged during polishing, which is shown in Table 2.

TABLE 2 polishing results for inventive examples 1-17 and comparative examples 1-3

As seen from Table 2, the polishing solutions of examples 1 to 17 according to the present invention had better stability during recycling than those of comparative examples 1 to 3, which did not contain the anti-oxidative discoloration agent. Specifically, the polishing liquids of comparative examples 1 to 3, which contained silicon polishing rate accelerator but no anti-oxidative discoloration agent, were yellow-blackened in color due to accumulation of by-products after cyclic polishing for 0.5 to 1 hour, and the polishing rate was lowered.

In the embodiments 1 to 17 of the present invention, the consumption of the speed accelerator in the polishing solution can be reduced by adding the anti-oxidation discoloration agent to the polishing solution, so as to inhibit the generation and accumulation of polishing by-products, and to maintain the polishing solution at an excellent polishing rate during the recycling process, as can be seen from table 2, the polishing solution of the present invention can be recycled for at least 2 hours. However, referring to example 16, by increasing the contents of the silicon polishing rate accelerator and the oxidation discoloration inhibitor in the polishing solution, it is possible to recycle the polishing solution for up to 8 hours.

In conclusion, the polishing solution disclosed by the invention has higher stability in a longer time by adding the oxidation and color change resistant agent, keeps the polishing performance not to be attenuated in the recycling process, avoids the problems of pipeline blockage, polishing product scratching and the like caused by accumulation of byproducts, prolongs the quality of the polishing product, prolongs the recycling service life of the polishing solution, reduces the consumption of the polishing solution and greatly reduces the cost.

It should be noted that the contents in the present invention are all contents by mass percentage, if not specifically stated.

It should be understood that the embodiments of the present invention have been described in terms of preferred embodiments, and not as limitations of the invention, and that those skilled in the art may readily modify or modify the embodiments in accordance with the teachings herein without departing from the scope of the invention.

Claims

1. Use of a chemical mechanical polishing solution comprising silica abrasive particles, a polishing rate accelerator, a pH adjuster, an anti-oxidation discoloration agent, and water to improve stability and cyclic utilization of the polishing solution;

the mass percentage content of the silicon dioxide grinding particles is 0.1-40%;

the polishing rate accelerator comprises one or more of piperazine, monoethanolamine and diethylenetriamine;

the polishing rate accelerator accounts for 0.1-20% by mass; the antioxidant discoloration agent comprises one or more of benzotriazole, 1,2, 3-triazole, benzimidazole, 5-phenyl-1H-tetrazole, ascorbic acid, tea polyphenol, uric acid, cyanuric acid, barbituric acid, glucuronic acid, squaric acid, adenosine, purine, nicotinamide, flavonol and anthocyanin;

the content of the antioxidant discoloration agent is 0.0001-1% by mass;

the pH value of the chemical mechanical polishing solution is 10-12.

2. Use according to claim 1,

the mass percentage content of the silicon dioxide grinding particles is 15% -30%.

3. Use according to claim 1,

the pH regulator comprises one or more of KOH, nitric acid and tetramethylammonium hydroxide.