Chemical mechanical polishing composition

Abstract

The invention provides a chemical mechanical polishing composition. The polishing composition which is high in polishing speed and low in tungsten corrosion is obtained by combining a grinding agent with organic carboxylic acid, an oxidizing agent and a corrosion inhibitor. The technical problem to be solved by the invention is to reduce the corrosion rate of tungsten without influencing the polishing speed of tungsten, thereby reducing the defect risk and improving the yield.

Description

Technical Field

[0001] The present invention relates to the technical field of chemical reagents for semiconductor manufacturing, and particularly to a polishing composition containing a tungsten corrosion inhibitor. Background Art

[0002] Integrated circuits are composed of millions of components on a silicon substrate, and these components are interconnected through multi-layer interconnect technologies. The interconnect structure usually has a first metallization layer, an interconnect layer, a second metallization layer, and usually third and subsequent metal layers. The connections between different interconnect levels are made using metal vias. With the deposition and removal of multi-layer materials, each layer of the wafer needs to be planarized. These non-planarities can lead to various defects in the product, so the planarization technology for conductive layers and insulating dielectric layers has become crucial. In the 1980s, the chemical mechanical polishing (CMP) technology pioneered by IBM was considered the most effective method for global planarization currently.

[0003] In a typical CMP process, the wafer is fixed on a face-down polishing head, and the surface of the polishing platen is covered with a polishing pad. Under a certain pressure, the polishing head moves linearly on the polishing pad or rotates along the same movement direction as the polishing table. The polishing slurry with abrasive particles flows onto the table, and under the dual action of chemistry and mechanics, the surface of the wafer is polished and global planarization is achieved. CMP can be used to remove unwanted surface topographies and surface defects, such as rough surfaces, adsorbed impurities, lattice damage, scratches, etc.

[0004] In integrated circuit design, CMP technology has become the preferred method for realizing tungsten interconnects. Tungsten is often used in the integrated circuit design of contacts / vias. Tungsten is a hard metal and chemically inert, which poses challenges to tungsten CMP. Many CMP slurries used for polishing tungsten cause erosion and recession problems due to their corrosiveness. In severe cases, cavities appear in the dielectric layer, affecting the electrical performance. Therefore, a CMP polishing method and composition for tungsten are needed, which can inhibit the corrosion of tungsten wafers, as well as the recession of tungsten and the erosion of metal line arrays.

[0005] In view of this problem, it is particularly important to develop a CMP slurry that can inhibit tungsten corrosion. For example, US Patent US2021340445 discloses a CMP slurry using a bicyclic amidine additive, which can provide a low dishing and low erosion topography. The addition of bicyclic amidine can reduce the dishing and erosion for most arrays to a certain extent. However, with the development of chip manufacturing technology, chip circuits are becoming increasingly complex, which puts higher requirements on the polishing liquid. The inhibition effect of bicyclic amidine is not obvious and it is difficult to adapt to the high-demand tungsten polishing environment. US Patent US 6083419 discloses a method of using amino acids as tungsten polishing corrosion inhibitors. The addition of amino acids has a certain effect on inhibiting the corrosion of tungsten, but it will affect the normal polishing speed of tungsten during the polishing process. US Patent US10286518 discloses a tungsten polishing composition, which uses a CMP method of a thiol alkoxy compound in the composition, inhibits tungsten dishing and the erosion of the underlying TEOS and has the performance of further inhibiting the corrosion rate, but its inhibition effect in the wide line region is general. From the above facts, it can be seen that for tungsten polishing compositions, inhibiting the corrosion of tungsten is not only challenging but also of important practical significance. Summary of the Invention

[0006] The present invention provides a chemical mechanical polishing composition, which uses an abrasive, an organic carboxylic acid, an oxidizing agent, and a nicotine-based polyazaoolefin compound to obtain a polishing liquid composition that can have a high polishing speed and low tungsten corrosion. The technical problem solved by the present invention is to reduce the corrosion rate of tungsten without affecting the polishing speed of tungsten, thereby reducing the defect risk and improving the yield.

[0007] The present invention discloses a chemical mechanical polishing composition, comprising: abrasive particles, a nicotine-based polyazaoolefin compound, an organic carboxylic acid, an oxidizing agent, and water.

[0008] Further, the nicotine-based polyazaoolefin compound is selected from one or more of nitenpyram, imidacloprid, and acetamiprid.

[0009] Further, the mass percentage content range of the nicotine-based polyazaoolefin compound is: 0.003% to 0.5%. Preferably, the mass percentage content range of the nicotine-based polyazaoolefin compound is: 0.005% to 0.1%.

[0010] Further, in the chemical mechanical polishing composition, the abrasive particles are selected from alumina, silica, and mixtures thereof.

[0011] Further, the mass percentage content range of the abrasive particles is: 0.01% to 5%. Preferably, the mass percentage content range of the abrasive particles is: 0.01% to 3.5%.

[0012] Further, in the chemical mechanical polishing composition, the organic carboxylic acid is preferably a dicarboxylic acid.

[0013] Further, in the chemical mechanical polishing composition, the organic carboxylic acid is selected from one or more of lactic acid, succinic acid, malonic acid, tartaric acid, gluconic acid, phthalic acid, malic acid, and glycolic acid.

[0014] Further, the mass percentage content range of the organic carboxylic acid is: 0.01% to 5%. Preferably, the mass percentage content range of the organic carboxylic acid is: 0.01% to 2%.

[0015] Further, in the chemical mechanical polishing composition, the oxidizing agent is hydrogen peroxide and / or iron nitrate.

[0016] Further, the mass percentage content range of the oxidizing agent is 0.001% to 4%.

[0017] Further, the pH value of the chemical mechanical polishing composition is 2 to 7.

[0018] After adopting the above technical solution, compared with the prior art, it has the following beneficial effects:

[0019] 1. The polishing composition disclosed in the present invention mainly achieves the polishing effect on tungsten and silicon oxide through malonic acid, iron, hydrogen peroxide, and specific aluminum oxide or silicon oxide abrasives. Most importantly, by adding nicotine-based polyazaolefins, the static corrosion problem of tungsten is effectively reduced.

[0020] 2. The polishing composition disclosed in the present invention can provide a relatively high tungsten polishing rate and a relatively low silicon oxide polishing rate. Most importantly, the composition exhibits a very low tungsten static corrosion rate, thereby achieving surface flatness. Specific Embodiments

[0021] The chemical mechanical polishing composition for polishing tungsten of the present invention is described in detail below through specific examples to better understand the present invention, but the following examples do not limit the scope of the present invention.

[0022] For the specific examples and comparative examples, according to the formulas given in Table 1, all components are mixed evenly, and water is added to make up the mass percentage to 100%. The pH is adjusted to the desired value with a pH regulator. The polishing compositions of Examples 1-13 and Comparative Examples 1-6 are obtained. All components used in the present invention are commercially available.

[0023] Table 1 Formulas of Examples 1-13 and Comparative Examples 1-6 (the % all refer to mass percentage content)

[0024]

[0025]

[0026] Experiments were conducted according to the formulation in Table 1 under the following experimental conditions:

[0027] Specific polishing conditions: pressure 1.5 psi, rotational speeds of the polishing pad and polishing head 93 / 87 rpm, polishing pad IC1010, polishing liquid flow rate 300 mL / min, polishing machine 12” Reflexion LK, polishing time 1 min.

[0028] The morphology of the wafer surface was measured using Park systems NX-Wafer.

[0029] Static corrosion test of tungsten: Immerse a tungsten wafer of about 5 cm × 5 cm into the preheated polishing slurry at 45 degrees, immerse for 2 min, take out and rinse, and then test the static corrosion data using the four-point probe method.

[0030] The experimental results obtained are shown in Table 2.

[0031] Table 2 Polishing rate and tungsten static corrosion rate tests of Examples 1-13 and Comparative Examples 1-6

[0032]

[0033]

[0034] Combining Table 1 and Table 2, the polishing results of Examples 1-5 and Comparative Example 1 show that the polishing composition of the present invention can perform high-speed polishing of tungsten and does not affect the low-speed removal of silicon oxide. The corrosion rate test results show that with the addition of the nicotine-based poly-nitroolefin compound, the corrosion of the tungsten wafer significantly decreases.

[0035] By comparing Examples 4-5 with Examples 1-3, it is found that on the basis of the same abrasive particles, organic carboxylic acid, oxidant and pH, compared with other slurries, the polishing composition containing nitenpyram can more effectively reduce the static corrosion of tungsten without affecting the polishing rate of tungsten.

[0036] For the preferred nitenpyram, as its amount increases, the corrosion inhibition effect also becomes correspondingly better, and the best effect is achieved at a concentration of 0.06% nitenpyram. As the amount increases, the erosion inhibition effect does not increase significantly.

[0037] Organic carboxylic acids are components of stable oxidants in the polishing liquid system. In the absence of a stabilizer, the oxidant will rapidly degrade due to the Fenton reaction. Available stabilizers include one or more of lactic acid, succinic acid, malonic acid, tartaric acid, gluconic acid, phthalic acid, malic acid, and glycolic acid. Binary carboxylic acids are preferred. Their bonding with metals will slow down the decomposition of hydrogen peroxide. In addition, organic carboxylic acids also have the function of pH buffering and reducing pH fluctuations. In some formulation systems, they also have the function of stabilizing the dispersion of abrasives. Therefore, in most cases, organic carboxylic acids play a key role in the polishing liquid system.

[0038] Examples 6 - 13 show that nitenpyram can achieve good tungsten corrosion inhibition effects under different conditions of pH, abrasive type, concentration, organic acid type, concentration, and oxidant.

[0039] By comparing Comparative Examples 1 - 4 with Example 2, it is found that although amino acids, cyromazine, and butylamide can inhibit the static corrosion of tungsten to a certain extent, at the same addition concentration, amino acids will affect the polishing rate of tungsten, and the corrosion inhibition effects of cyromazine and butylamide are relatively poor. This shows that the present invention has better corrosion inhibition advantages and does not affect the tungsten polishing rate. From Comparative Examples 5 and 6, it can be seen that when the addition amount is less than 0.003%, the wafer protection effect is not obvious. When the addition amount is higher than 0.5%, the corrosion inhibition effect does not increase significantly, and it will bring the risk of instability of the polishing liquid system. The optimal concentration range is 0.003% - 0.1%.

[0040] In summary, the present invention provides a chemical mechanical polishing composition for tungsten polishing. By using an abrasive, an organic carboxylic acid, an oxidant, and a nicotine - type poly - nitrogen olefin compound, a polishing composition with high polishing rate and low tungsten corrosion can be obtained. The technical problem solved by the present invention is to reduce the corrosion rate of tungsten without affecting the polishing rate of tungsten, thereby reducing the defect risk and improving the yield.

[0041] It should be noted that the embodiments of the present invention have good implementability and do not limit the present invention in any form. Any person skilled in the art may use the disclosed technical content to change or modify 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 - mentioned 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 composition, characterized in that, Containing: abrasive particles, nicotinic polyazaolefins, organic carboxylic acids, oxidants and water.

2. The chemical mechanical polishing composition according to claim 1, wherein The nicotinic polyazaolefins are selected from one or more of nitenpyram, imidacloprid, acetamiprid.

3. The chemical mechanical polishing composition according to claim 1, wherein The mass percentage content range of the nicotinic polyazaolefins is: 0.003% - 0.5%.

4. The chemical mechanical polishing composition according to claim 3, wherein The mass percentage content range of the nicotinic polyazaolefins is: 0.005% - 0.1%.

5. The chemical mechanical polishing composition according to claim 1, wherein The abrasive particles are selected from alumina, silica and their mixtures.

6. The chemical mechanical polishing composition according to claim 1, characterized in that, The mass percentage content range of the abrasive particles is: 0.01% - 5%.

7. The chemical mechanical polishing composition according to claim 6, wherein The mass percentage content range of the abrasive particles is: 0.01% - 3.5%.

8. The chemical mechanical polishing composition according to claim 1, wherein The organic carboxylic acid is a dicarboxylic acid.

9. The chemical mechanical polishing composition according to claim 8, wherein The organic carboxylic acid is selected from one or more of lactic acid, succinic acid, malonic acid, tartaric acid, gluconic acid, phthalic acid, malic acid, glycolic acid.

10. The chemical mechanical polishing composition according to claim 1, wherein The mass percentage content range of the organic carboxylic acid is: 0.01% - 5%.

11. The chemical mechanical polishing composition according to claim 10, wherein The mass percentage content range of the organic carboxylic acid is: 0.01% - 2%.

12. The chemical mechanical polishing composition according to claim 1, wherein, The oxidant is hydrogen peroxide and / or iron nitrate.

13. The chemical mechanical polishing composition according to claim 1, wherein The mass percentage content range of the oxidant is 0.001% - 4%.

14. The chemical mechanical polishing composition according to any one of claims 1-13, characterized in that, The pH value is 2 - 7.

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