Chemical mechanical polishing solution and application thereof

Abstract

The invention provides a chemical mechanical polishing solution. The chemical mechanical polishing solution comprises silicon dioxide grinding particles, a sulfonic compound and a compound containing two or more hydroxyl groups. The chemical mechanical polishing solution has a high carbon material removal rate and a low silicon nitride removal rate, and can realize a high carbon material and silicon nitride removal rate selection ratio.

Description

Technical Field

[0001] The present invention relates to the field of chemical mechanical polishing, and particularly to a chemical mechanical polishing liquid and its use. Background Art

[0002] Carbon-containing materials have attracted much attention due to their excellent properties such as high hardness, high strength, high thermal conductivity, high resistivity, high radiation resistance, high chemical stability, low friction coefficient, and good transmittance in the infrared optical band. They have great application potential in high-temperature, high-frequency, high-power, and radiation-resistant high-density integrated electronic devices, etc.

[0003] As semiconductor processes become more advanced, the chip manufacturing process requires more refined pattern improvements, and the lithography laser wavelength gradually decreases with the process improvement. Generally, the thickness of the photosensitive film is reduced to control the pattern resolution. However, an overly thin photosensitive film will cause the photosensitive film to be etched away before the underlying material, resulting in pattern deformation. Therefore, it is necessary to additionally form a hard mask film other than the photosensitive film pattern on the underlying material. In the past, silicon dioxide or silicon nitride was usually selected as the hard mask to ensure a processing margin during the etching process for forming the pattern. However, the thickness requirements for the hard mask also become smaller and smaller with the process improvement. In order to obtain higher resolution and reduce necking and footing of the material, carbon-containing materials with more stable chemical properties and less diffuse reflection are usually used as the hard mask.

[0004] Carbon-containing material thin films can be formed by known CVD (Chemical Vapor Deposition) methods, PVD (Physical Vapor Deposition) methods, and spin-on carbon methods. In PVD methods represented by sputtering, the formation of carbon-containing material films has directionality. Therefore, in order to form a uniform carbon-containing material thin film, measures must be taken to rotate the substrate or place multiple targets in the device. The structure of the device for forming carbon-containing material thin films is complex, expensive, and sometimes it is difficult to form carbon-containing material thin films according to the shape of the substrate. The CVD method forms carbon-containing material thin films from reaction gases, and its device structure is simple and inexpensive. Therefore, the prior art usually uses plasma CVD methods to form carbon-containing material thin films, that is, hydrocarbons such as naphthalene, benzene, and toluene having a benzene ring or multiple double bonds are usually used as reaction gases. However, in fine processes of 50 nm or less, there are obvious residue problems with bubble-type carbon particles and dripping-type carbon particles generated during the transfer process of the amorphous carbon layer produced by the CVD process. By selecting appropriate deposition techniques and changing deposition parameters, the C sp2 and sp3 hybridization ratios in the carbon-containing material thin film can be changed to further control the properties of the film.

[0005] Therefore, in order to improve the lithography accuracy used in the semiconductor device manufacturing process, the interlayer flatness in each process is a very important factor. However, since carbon-containing materials are usually very stable at room temperature, not prone to chemical reactions, and the greater the sp3 hybridization content, the greater the Mohs hardness, when the commonly used chemical mechanical polishing fluid is used to polish carbon-containing materials, there will be difficulties such as great difficulty in planarization processing and long processing time. In some processes using silicon nitride as the stop layer, to make the carbon-containing material thin film on the chip meet the grinding rate level and stop on the silicon nitride layer, this requires the polishing fluid to have a high removal rate of carbon materials, a low removal rate of silicon nitride, and a high selectivity ratio of carbon material and silicon nitride removal rates. Summary of the Invention

[0006] In order to overcome the above technical defects, the purpose of the present invention is to provide a chemical mechanical polishing fluid.

[0007] Specifically, the present invention discloses a chemical mechanical polishing fluid, comprising: silica abrasive particles, sulfonic acid group compounds, and compounds containing two or more hydroxyl groups.

[0008] Preferably, the abrasive particles are silica abrasive particles with a particle size of 30 - 100 nm.

[0009] Preferably, the mass percentage concentration of the abrasive particles is 0.1 - 10%.

[0010] Preferably, the mass percentage concentration of the abrasive particles is 0.1 - 5%

[0011] Preferably, the sulfonic acid group compounds are one or more selected from sodium ethanesulfonate, sodium 4-styrenesulfonate, 2-morpholinoethanesulfonic acid, 4-(2-hydroxyethyl)piperazine-1-ethanesulfonic acid, p-toluenesulfonic acid, 4-toluenesulfonic acid, 2-aminoethanesulfonic acid, sodium dimethyldinaphthalenesulfonate, 3-N,N-bis(2-hydroxyethyl)amino-2-hydroxypropanesulfonic acid, dodecylbenzenesulfonic acid, sodium dodecylbenzenesulfonate, poly(styrenesulfonic acid), poly(p-styrenesulfonic acid), sodium polynaphthalene formaldehyde sulfonate, sodium polydithiodipropanesulfonate, potassium straight-chain polyepoxynaphthol propanesulfonate, poly(3,4-ethylenedioxythiophene)styrenesulfonic acid.

[0012] Preferably, the mass percentage concentration of the sulfonic acid group compounds is 0.01 - 0.5%.

[0013] Preferably, the mass percentage concentration of the sulfonic acid group compounds is 0.01% - 0.3%.

[0014] Preferably, the compound containing two or more hydroxyl groups is selected from one or more of pentaerythritol, ethylene glycol, 1,2 - propylene glycol, 2 - methyl - 1,2 - propanediol, 1,4 - butanediol, 1,6 - hexanediol, neopentyl glycol, diethylene glycol, dipropylene glycol, trimethylolpropane, glycerol, xylitol, glucose, ascorbic acid, sorbitol, sucrose, methylcellulose, hydroxypropyl methylcellulose, hydroxyethyl cellulose, carboxymethyl cellulose, polyethylene glycol 200, polyethylene glycol 400, polyethylene glycol 1000, polyethylene glycol 2000, polyethylene glycol 6000, polyethylene glycol 8000, polyethylene glycol 20000.

[0015] Preferably, the mass percentage concentration of the compound containing two or more hydroxyl groups is 0.01 - 5%.

[0016] Preferably, the mass percentage concentration of the compound containing two or more hydroxyl groups is 0.1 - 1%.

[0017] Preferably, it further includes a pH regulator and a bactericide.

[0018] Preferably, the pH value of the chemical mechanical polishing liquid is 2 - 6.

[0019] The polishing liquid of the present invention can be concentrated and configured, and when in use, it is diluted with water to the concentration range of the present invention for use.

[0020] On the other hand, the present invention discloses a use of the chemical mechanical polishing liquid as described above in any one for polishing carbon - containing materials.

[0021] Compared with the prior art, the chemical mechanical polishing liquid in the present invention can meet the requirements that the polishing liquid has a higher removal rate of carbon - containing materials and a lower removal rate of silicon nitride, and achieves a higher selectivity ratio of the removal rate of carbon - containing materials to silicon nitride. Detailed Embodiments

[0022] The advantages of the present invention are further elaborated through the following specific examples.

[0023] Table 1 shows the components and their contents (mass concentration) of Comparative Examples 1 - 9 and Examples 1 - 20 of the chemical mechanical polishing liquid of the present invention. According to the formula given in the table, all components are dissolved and mixed evenly, and the mass percentage is made up to 100% with water. The pH value of the polishing liquid is adjusted to the required pH value with a pH regulator.

[0024] Table 1 Components and Contents of the Chemical Mechanical Polishing Liquid of Comparative Examples 1 - 9 and Examples 1 - 20 of the Present Invention

[0025]

[0026]

[0027] The polishing liquid prepared according to the formulation in Table 1 is polished under the following conditions.

[0028] Specific polishing conditions: The polishing machine is Reflexion LK, the polishing pad is IC1010 polishing pad, 300mm wafers are used, the polishing pressure is 3.0 psi, the rotation speed of the polishing platen is 93 revolutions per minute, the rotation speed of the polishing head is 87 revolutions per minute, the flow rate of the polishing liquid is 300 ml / min, and the polishing time is 1 min. The removal rates of each polishing liquid for carbon-containing materials and silicon nitride and the selectivity ratio of the removal rate of carbon-containing materials to silicon nitride are measured and recorded in Table 2.

[0029] Table 2 Polishing test results of the chemical mechanical polishing liquids of Comparative Examples 1-9 and Examples 1-20 of the present invention

[0030]

[0031]

[0032] It can be seen from the test results in Table 2 that from Comparative Examples 1-2, when polishing is carried out only using SiO2, there is basically no removal rate for carbon-containing materials, and the selectivity ratio of the removal rate for silicon nitride is also very low. Based on Comparative Example 4 and Comparative Example 5, it can be known that polishing liquids using only sulfonic acid analogs of non-sulfonic acid compounds and hydroxy compounds not containing two or more hydroxyl groups cannot achieve high selectivity for carbon-containing materials and silicon nitride.

[0033] Based on Comparative Example 3, Comparative Example 6 and Comparative Example 7, it can be known that adding a compound containing two or more hydroxyl groups alone and adding a compound containing a sulfonic acid group alone cannot simultaneously meet the requirements of a high polishing rate for carbon-containing materials and a high selectivity ratio of the removal rate to silicon nitride. Based on the polishing test results of Example 1 and Comparative Examples 6 and 7, when a sulfonic acid group compound and a compound containing two or more hydroxyl groups are added simultaneously, the removal rate of the polishing liquid for carbon-containing materials is significantly increased, and the selectivity ratio of the removal rate of carbon materials to silicon nitride can be effectively improved. From the test results of Comparative Examples 8, 9 and the Examples, it can be known that when the pH environment of the polishing liquid in the present invention is outside the range of 2-6, the required technical requirements cannot be achieved.

[0034] In summary, by adding a compound containing one or more sulfonic acid groups and a compound containing two or more hydroxyl groups to the polishing liquid, the present invention significantly improves the removal rate of the polishing liquid for carbon-containing materials, reduces the removal rate of silicon nitride, and can achieve a sufficient selectivity ratio of the removal rate.

[0035] It should be noted that the embodiments of the present invention have better implementability and do not impose any form of limitation on the present invention. Any person skilled in the art may use the technical content disclosed above to modify or transform it into an equivalent effective embodiment. However, as long as it does not depart from the technical solution of the present invention, any modification, equivalent change or modification made to the above embodiments based on the technical essence of the present invention still falls within the scope of the technical solution of the present invention.

Claims

1. A chemical mechanical polishing liquid, characterized in that including: it contains abrasive particles, sulfonic acid group compounds and compounds containing two or more hydroxyl groups.

2. The chemical mechanical polishing liquid according to claim 1, characterized in that the abrasive particles are silica abrasive particles with a particle size of 30 - 100 nm.

3. The chemical mechanical polishing liquid according to claim 1, characterized in that the mass percentage concentration of the abrasive particles is 0.1 - 10%.

4. The chemical mechanical polishing liquid according to claim 3, characterized in that the mass percentage concentration of the abrasive particles is 0.1 - 5%.

5. The chemical mechanical polishing liquid according to claim 1, characterized in that the sulfonic acid group compound is selected from one or more of sodium ethanesulfonate, sodium 4-styrenesulfonate, 2-morpholinoethanesulfonic acid, 4-(2-hydroxyethyl)piperazine-1-ethanesulfonic acid, p-toluenesulfonic acid, 4-toluenesulfonic acid, 2-aminoethanesulfonic acid, sodium dimethyldinaphthalenesulfonate, 3-N,N-bis(2-hydroxyethyl)amino-2-hydroxypropanesulfonic acid, dodecylbenzenesulfonic acid, sodium dodecylbenzenesulfonate, poly(styrenesulfonic acid), poly(p-styrenesulfonic acid), sodium polynaphthalene formaldehyde sulfonate, sodium polydithiodipropanesulfonate, potassium straight-chain polyepoxynaphthol propanesulfonate, poly(3,4-ethylenedioxythiophene)styrenesulfonic acid.

6. The chemical mechanical polishing liquid according to claim 1, characterized in that the mass percentage concentration of the sulfonic acid group compound is 0.01 - 0.5%.

7. The chemical mechanical polishing liquid according to claim 6, characterized in that the mass percentage concentration of the sulfonic acid group compound is 0.01% - 0.3%.

8. The chemical mechanical polishing liquid according to claim 1, characterized in that the compound containing two or more hydroxyl groups is selected from one or more of pentaerythritol, ethylene glycol, 1,2-propanediol, 2-methyl-1,2-propanediol, 1,4-butanediol, 1,6-hexanediol, neopentyl glycol, diethylene glycol, dipropylene glycol, trimethylolpropane, glycerol, xylitol, glucose, ascorbic acid, sorbitol, sucrose, methyl cellulose, hydroxypropyl methyl cellulose, hydroxyethyl cellulose, carboxymethyl cellulose, polyethylene glycol 200, polyethylene glycol 400, polyethylene glycol 1000, polyethylene glycol 2000, polyethylene glycol 6000, polyethylene glycol 8000, polyethylene glycol 20000.

9. The chemical mechanical polishing liquid according to claim 1, characterized in that the mass percentage concentration of the compound containing two or more hydroxyl groups is 0.01 - 5%.

10. The chemical mechanical polishing liquid according to claim 9, characterized in that the mass percentage concentration of the compound containing two or more hydroxyl groups is 0.1 - 1%.

11. The chemical mechanical polishing liquid according to any one of claims 1 - 10, characterized in that the pH value of the chemical mechanical polishing liquid is 2 - 6.

12. A process of using the chemical mechanical polishing liquid according to any one of claims 1 - 11 for polishing carbon-containing materials.

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