Chemical mechanical polishing composition and application thereof

Abstract

The invention provides a chemical mechanical polishing composition. The chemical mechanical polishing composition comprises grinding particles, a catalyst, an accelerant, polybasic acid and water. The chemical mechanical polishing solution disclosed by the invention can be used for remarkably removing silicon boride under an acidic condition, so that the polishing selection ratio of the polishing solution to different materials is adjusted.

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] The rapid development of modern chip technology has greatly promoted the miniaturization process of integrated circuit components. To ensure the normal distribution and effective operation of circuit components at the nanoscale, the planarization degree of the wafer surface must also reach the corresponding level. Currently, the most effective method to achieve this goal is chemical mechanical polishing (CMP) technology.

[0003] A semiconductor wafer typically includes a substrate on which a plurality of transistors have been formed, such as silicon or gallium arsenide. The transistors are chemically and physically connected to the substrate by patterning regions in the substrate and layers on the substrate. The transistors and layers are separated by an interlayer dielectric (ILD) mainly containing some form of silicon dioxide (SiO2). The transistors are interconnected with each other by using well-known multi-level interconnections. A typical multi-level interconnection includes a stacked thin film composed of one or more of the following materials: titanium (Ti), titanium nitride (TiN), tantalum (Ta), aluminum-copper (Al-Cu), aluminum-silicon (Al-Si), copper (Cu), tungsten (W), doped polysilicon (poly-Si), and various combinations thereof. In addition, transistors or groups of transistors are usually isolated from each other by using trenches filled with insulating materials such as silicon dioxide, silicon nitride, or polysilicon.

[0004] Chemical mechanical polishing involves both chemical and mechanical actions. Generally, the wafer is fixed to a polishing head, and its front surface is brought into contact with a polishing pad in a CMP device. Under a certain pressure, the polishing head linearly moves on the polishing pad or rotates along a movement direction consistent with the polishing table. At the same time, a certain flow rate of a polishing composition ("slurry") is injected between the wafer and the polishing pad, and the slurry is evenly spread on the polishing pad due to centrifugal force. Thus, under the dual action of chemistry and mechanics, the surface of the wafer is polished and global planarization is achieved.

[0005] With the further improvement and development of the structure and function of semiconductor components, a simple polysilicon structure cannot meet the corresponding specific requirements, and corresponding elements such as boron, phosphorus, and carbon need to be doped into single-crystalline silicon to change the chemical and physical properties of polysilicon to meet the above requirements. Although many known CMP slurry compositions are suitable for polishing polysilicon, there is no relevant research on CMP polishing compositions for boron-doped polysilicon. Summary of the Invention

[0006] To overcome the above technical defects, the purpose of the present invention is to provide a chemical mechanical polishing liquid capable of removing boron-doped silicon under acidic conditions.

[0007] Specifically, the present invention discloses a chemical mechanical polishing composition, comprising: abrasive particles, a catalyst, an accelerator, a polybasic acid and water.

[0008] Preferably, the abrasive particles are selected from one or more of alumina, cerium oxide, zirconium oxide, titanium oxide or silica;

[0009] The mass percentage concentration of the abrasive particles is 0.1 wt% to 30 wt%.

[0010] Preferably, the abrasive particles are silica particles;

[0011] The mass percentage concentration of the abrasive particles is 0.5 wt% to 20 wt%.

[0012] Preferably, the catalyst is selected from one or more of alkali metal salts, alkaline earth metal salts and ammonium salts;

[0013] The mass percentage concentration of the catalyst is 0.001 wt% to 1 wt%.

[0014] Preferably, the alkali metal salt is selected from one or more of sodium salts and potassium salts;

[0015] The alkaline earth metal salt is selected from one or more of magnesium salts and calcium salts;

[0016] The mass percentage concentration of the catalyst is 0.01 wt% to 0.5 wt%.

[0017] Preferably, the accelerator is one or more of polyhydric alcohols and polyamide compounds;

[0018] The mass percentage concentration of the accelerator is 0.1 wt% to 10 wt%.

[0019] Preferably, the polyhydric alcohol is selected from one or more of ethylene glycol, glycerol, pentaerythritol, trimethylolethane, xylitol, sorbitol and polyethylene glycol;

[0020] The mass percentage concentration of the accelerator is 0.1 wt% to 5 wt%.

[0021] Preferably, the polybasic acid is selected from one or more of oxalic acid, malonic acid, succinic acid, glutaric acid, lactic acid, succinic acid, citric acid;

[0022] The mass percentage concentration of the polybasic acid is 0.01 wt% to 1 wt%.

[0023] Preferably, the mass percentage concentration of the polybasic acid is 0.01 wt% to 0.5 wt%.

[0024] Preferably, it further contains a pH regulator, which is selected from one or more of nitric acid, sulfuric acid, phosphoric acid, sodium hydroxide, potassium hydroxide, and ammonia water.

[0025] Preferably, the pH value of the chemical mechanical polishing composition is 2 - 7.

[0026] The present invention also discloses a use of the chemical mechanical polishing composition described above in any one for polishing silicon boride.

[0027] The chemical mechanical polishing liquid in the present invention can significantly remove silicon boride under acidic conditions, thereby adjusting the polishing selectivity ratio of the polishing liquid for different materials. Detailed Description of the Invention

[0028] The advantages of the present invention will be further elaborated below in conjunction with specific embodiments.

[0029] For the specific embodiments and the comparison, according to the formula given in Table 1, all components are dissolved and mixed evenly, and the mass percentage is made up to 100% with water. The pH is adjusted to the desired value with a pH regulator. Among them, the abrasive particles are silicon dioxide, and the polybasic acid is citric acid. The % in the concentration in the embodiments refers to the mass concentration.

[0030] Table 1 Components and Contents of the Chemical Mechanical Polishing Liquids of Examples 1 - 15 and Comparative Examples 1 - 5

[0031]

[0032]

[0033] The properties of the chemical mechanical polishing liquid in the embodiments of the present invention are further characterized. The polishing liquids in the embodiments and the comparative examples are used for

[0034] Specific polishing conditions: pressure 2.0 psi, the rotation speeds of the polishing pad and the polishing head are 93 / 87 rpm, the polishing pad is IC1000, the flow rate of the polishing liquid is 300 mL / min, the polishing machine is LK, and the polishing time is 1 min. The polishing rates of SiB and Oxide are measured using a non - metal film thickness measuring instrument, as shown in Table 2.

[0035] Table 2 Polishing Test Results of the Chemical Mechanical Polishing Liquids of Examples 1 - 15 and Comparative Examples 1 - 5

[0036]

[0037]

[0038] Comparative Examples 1 - 5 show that adding a promoter under acidic conditions can significantly increase the removal rate of silicon boride.

[0039] By comparing Examples 1, 2, 4, 8, 9 and Comparative Examples 1-5, it can be seen that while adding a promoter, adding a suitable catalyst can further increase the removal rate of silicon boride.

[0040] From Examples 1-15, it can be seen that by appropriately adjusting the types and concentrations of the catalyst and the promoter, different selectivity ratios of the removal rates of silicon boride and silicon oxide can be obtained.

[0041] By comparing Example 1 with Comparative Examples 6 and 7, it can be found that using other metals such as iron and aluminum instead of alkaline earth metals or alkali metals cannot achieve a sufficient SiB removal rate. By comparing Example 1 with Comparative Examples 8 and 9, it can be found that using monohydric alcohols such as ethanol and propanol also cannot obtain a fast SiB removal rate.

[0042] In summary, the present patent proposes that under acidic conditions, silicon boride can be significantly removed, thereby adjusting the selectivity ratio of different materials.

[0043] 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 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 composition, characterized in that, Comprising: Abrasive particles, a catalyst, an accelerator, a polybasic acid, and water.

2. The chemical mechanical polishing composition according to claim 1, wherein The abrasive particles are selected from one or more of alumina, cerium oxide, zirconium oxide, titanium oxide, or silica; The mass percentage concentration of the abrasive particles is 0.1 wt% to 30 wt%.

3. The chemical mechanical polishing composition according to claim 2, wherein The abrasive particles are silica particles; The mass percentage concentration of the abrasive particles is 0.5 wt% to 20 wt%.

4. The chemical mechanical polishing composition according to claim 1, wherein The catalyst is selected from one or more of alkali metal salts and alkaline earth metal salts; The mass percentage concentration of the catalyst is 0.001 wt% to 1 wt%.

5. The chemical mechanical polishing composition according to claim 4, wherein The alkali metal salts are selected from one or more of sodium salts and potassium salts; The alkaline earth metal salts are selected from one or more of magnesium salts and calcium salts; The mass percentage concentration of the catalyst is 0.01 wt% to 0.5 wt%.

6. The chemical mechanical polishing composition according to claim 1, wherein The accelerator is one or more polyhydric alcohols; The mass percentage concentration of the accelerator is 0.1 wt% to 10 wt%.

7. The chemical mechanical polishing composition according to claim 6, wherein The polyhydric alcohols are selected from one or more of ethylene glycol, glycerol, pentaerythritol, trimethylolethane, xylitol, sorbitol, and polyethylene glycol; The mass percentage concentration of the accelerator is 0.1 wt% to 5 wt%.

8. The chemical mechanical polishing composition according to claim 1, wherein The polybasic acid is selected from one or more of oxalic acid, malonic acid, succinic acid, glutaric acid, lactic acid, succinic acid, and citric acid; The mass percentage concentration of the polybasic acid is 0.01 wt% to 1 wt%.

9. The chemical mechanical polishing composition according to claim 1, wherein The mass percentage concentration of the polybasic acid is 0.01 wt% to 0.5 wt%.

10. The chemical mechanical polishing composition according to claim 1, wherein It further contains a pH regulator, selected from one or more of nitric acid, sulfuric acid, phosphoric acid, sodium hydroxide, potassium hydroxide, and ammonia water.

11. The chemical mechanical polishing composition according to claim 1, wherein The pH value of the chemical mechanical polishing composition is 2 to 7.

12. A use of the chemical mechanical polishing composition according to any one of claims 1 - 11 for polishing silicon boride.

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