A cerium oxide-based polishing liquid for sti structure

Abstract

This invention provides a cerium oxide-based polishing slurry for STI structures. The slurry comprises, by total mass, 0.05 wt%–5 wt% nano-cerium dioxide abrasive, 0.02 wt%–0.2 wt% hydroquinone, 0.05 wt%–0.25 wt% pyridinecarboxylic acid, 0.01 wt%–0.5 wt% D-sorbitol, and 0.001 wt%–0.01 wt% 1,2-benzisothiazolin-3-one, with a pH of 3–5. The cerium oxide-based polishing slurry provided by this invention, by adding a reducing agent to gently fine-tune the CeO2 surface activity to increase the Ce3+ content, promotes the removal rate of TEOS. Through the synergistic effect of other inhibitors and passivators, a high TEOS:Si3N4 selectivity ratio is obtained. Inhibiting the removal rate of Si3N4 indirectly avoids excessive grinding of oxides in the trenches, resulting in better wafer surface planarization efficiency.

Description

Technical Field

[0001] This invention relates to the field of materials technology for semiconductor manufacturing, and in particular to a cerium oxide-based polishing slurry for STI structures. Background Technology

[0002] With the continuous improvement of semiconductor device integration, the requirements for dimensional control and planarization accuracy of shallow trench isolation (STI) structures are becoming increasingly stringent. Chemical mechanical planarization (CMP) has become a crucial step affecting device isolation quality, subsequent process windows, and yield. For STI structures, the polishing process needs to maintain a high removal efficiency for the oxide layer while maintaining a low removal rate for the silicon nitride barrier layer. At the same time, it is also necessary to control oxide depressions in the trench region to ensure wafer surface flatness and structural integrity.

[0003] While existing cerium oxide-based polishing slurries exhibit high polishing activity against oxides, they still have significant shortcomings in practical applications. On the one hand, simply increasing the surface activity of cerium oxide to improve the oxide removal rate can easily enhance the interaction between the abrasive and the oxide surface, resulting in more Si-O-Ce bonds and making post-CMP cleaning difficult. On the other hand, while pursuing a high oxide removal rate, it is often difficult to effectively protect the Si3N4 barrier layer, and over-grinding is prone to occur in the trench area, which in turn affects the selectivity control and planarization effect of the STI structure. To this end, a cerium oxide-based polishing slurry for STI structures is proposed. Summary of the Invention

[0004] In view of this, the present invention provides a cerium oxide-based polishing slurry for STI structures to solve or alleviate the technical problems existing in the prior art, and at least provides a beneficial alternative.

[0005] The technical solution of the present invention is embodied in the following aspects: a cerium oxide-based polishing slurry for STI structures is provided, comprising, by mass percentage of the total mass of the polishing slurry, 0.05wt% to 5wt% of nano-cerium dioxide abrasive, 0.02wt% to 0.2wt% of hydroquinone, 0.05wt% to 0.25wt% of pyridinecarboxylic acid, 0.01wt% to 0.5wt% of D-sorbitol, and 0.001wt% to 0.01wt% of 1,2-benzisothiazolin-3-one, wherein the pH value of the polishing slurry is 3 to 5; The above technical solution does not rely on a single component to unidirectionally enhance a certain performance. Instead, it uses a combination of abrasive components, oxide removal rate regulating components, silicon nitride suppression components, and trench depression control components to enable different materials to exhibit different removal behaviors in the same polishing system. This allows the polishing slurry to have both high selectivity and good planarization ability in the STI structural chemical mechanical planarization process.

[0006] Further preferred, nano-cerium dioxide abrasive is used as the main abrasive system of the polishing slurry to provide the basic mechanical action and interfacial chemical activity required for the removal of oxide materials; Cerium dioxide itself has high polishing activity for oxide materials and can still maintain good polishing ability under low solid content conditions. Therefore, using it as a base abrasive can balance removal efficiency and system stability. The content of the nano-cerium dioxide abrasive is set at 0.05wt% to 5wt%, which can ensure that the polishing liquid has sufficient effective contact interface and removal ability, while avoiding the increase in interparticle collision, decrease in dispersion stability or increase in local mechanical damage due to excessive abrasive content. Furthermore, the average particle size of the nano-cerium dioxide abrasive is 100 nm; By controlling the abrasive particle size at this level, the abrasive can achieve both good contact uniformity and stable dispersion at the polishing interface. Furthermore, the content of the nano-cerium dioxide abrasive is 0.25 wt%, which is suitable for forming a stable and coordinated cerium oxide-based polishing system together with the other components.

[0007] More preferably, the present invention introduces hydroquinone into the polishing solution; hydroquinone is an organic molecule with weak reducing properties, and its addition can affect the Ce content on the surface of cerium oxide abrasive. 3+ / Ce 4+ The proportions produce a regulating effect, thereby improving the reaction state of the abrasive surface and ensuring that the polishing system maintains a high oxide layer removal capacity without creating overly aggressive surface interactions. The hydroquinone content is set at 0.02wt%–0.2wt% to enable it to effectively participate in interface regulation under acidic working conditions. Furthermore, the hydroquinone content is 0.0138wt% to 0.0388wt%. By limiting its addition, a reasonable balance is maintained between the oxide layer removal capability and the morphology control of the groove area, avoiding excessive effects on the groove area in the later stages of polishing.

[0008] In a further preferred embodiment, the present invention further introduces pyridine carboxylic acid into the polishing solution. Pyridine carboxylic acid, as a silicon nitride removal rate inhibiting component, is beneficial to enhance the protection tendency of the Si3N4 layer at the polishing interface, thereby reducing the removal rate of silicon nitride material during the polishing process and forming a more favorable differential removal relationship between the oxide layer and the barrier layer. The content of pyridine carboxylic acid is set to 0.05wt% to 0.25wt%, so that it can coexist stably with the other components and effectively affect the removal behavior of the silicon nitride layer during the polishing process. Furthermore, the content of pyridine carboxylic acid is 0.05wt% to 0.15wt%. This further limitation enables the polishing slurry to maintain a high oxide layer removal efficiency while exhibiting a more significant inhibition effect on the Si3N4 layer, thereby improving the material selectivity of the entire STI structure polishing process.

[0009] In a further preferred embodiment, the present invention adds D-sorbitol to the polishing slurry. D-sorbitol molecules contain multiple hydroxyl groups, which can form a strong interfacial interaction on the oxide surface, thereby reducing the direct impact of the abrasive on the oxide in the groove region. This allows the polishing slurry to maintain effective removal in flat areas while exhibiting a gentler material removal method in groove regions. The content of D-sorbitol is set at 0.01wt% to 0.5wt% to ensure that it can both control groove depressions in the system and prevent excessive addition from affecting the overall removal efficiency. Furthermore, the content of D-sorbitol is 0.10wt% to 0.15wt%. Within this range, the polishing slurry has a more prominent ability to maintain the morphology of the groove area, which is beneficial for reducing dish-shaped defects and improving the step height state after polishing.

[0010] In a further preferred embodiment, the present invention also adds 1,2-benzisothiazolin-3-one as a bactericide to the polishing liquid, the content of which is 0.001wt% to 0.01wt%, mainly to improve the system stability of the polishing liquid during storage and use, and to inhibit the adverse effects of microbial growth on the slurry composition and dispersion state. Furthermore, the content of the 1,2-benzisothiazolin-3-one is 0.001 wt%. This bactericidal component enables the polishing solution to maintain a relatively stable composition and performance over a longer period, thereby ensuring that the above-mentioned multi-component synergistic relationship continues to play a role in practical applications.

[0011] More preferably, the present invention limits the pH value of the polishing slurry to 3-5. This pH range is conducive to the stability of each component in the polishing slurry in the same system, and is conducive to the synergistic realization of abrasive activity regulation, silicon nitride inhibition and trench depression control. Furthermore, the polishing slurry has a pH of 4.0. By controlling the pH within the aforementioned acidic range, the polishing slurry exhibits good process compatibility and stability during the STI structural chemimechanical planarization process.

[0012] The present invention also provides the application of the above-mentioned cerium oxide-based polishing slurry in the chemical mechanical planarization of STI structures.

[0013] Furthermore, the STI structure includes a TEOS oxide layer and a Si3N4 layer.

[0014] The embodiments of the present invention have the following advantages due to the adoption of the above technical solutions: The cerium oxide-based polishing slurry provided by this invention improves the surface activity of CeO2 by gently fine-tuning it with the addition of a reducing agent. 3+ The content of [specific ingredient] promotes the removal rate of TEOS. With the synergistic effect of other inhibitors and passivators, a higher TEOS:Si3N4 selectivity ratio is obtained. Inhibiting the removal rate of Si3N4 can indirectly avoid excessive grinding of oxides in the trenches and obtain better wafer surface planarization efficiency. Detailed Implementation

[0015] In the following description, only certain exemplary embodiments are briefly described. As those skilled in the art will recognize, the described embodiments can be modified in various ways without departing from the spirit or scope of the invention. Therefore, the description is considered to be exemplary in nature and not restrictive.

[0016] This invention provides a cerium oxide-based polishing slurry for STI structures. Using nano-cerium dioxide as the abrasive, under acidic pH conditions, through the synergistic formulation of hydroquinone, pyridine carboxylic acid, D-sorbitol and 1,2-benzisothiazolin-3-one, the polishing slurry exhibits high oxide layer removal capability, low silicon nitride layer removal tendency, and good trench morphology control capability during the chemical mechanical planarization process of STI structures. In the following examples, each component is prepared according to a mass percentage. Unless otherwise specified, all examples and comparative examples use conventional slurry preparation methods to prepare polishing solutions. The components are mixed and dispersed according to a predetermined ratio, and the pH is adjusted to a set value to obtain the corresponding polishing solution system.

[0017] Example 1 This embodiment illustrates the comprehensive performance of the polishing slurry under the basic formulation conditions of the present invention. In this embodiment, the polishing slurry comprises, by total mass, 0.25 wt% CeO2, 0.0275 wt% hydroquinone, 0.05 wt% pyridinecarboxylic acid, 0.10 wt% D-sorbitol, and 0.001 wt% 1,2-benzisothiazolin-3-one, and the pH value of the system is controlled at 4.0.

[0018] In this embodiment, nano-cerium dioxide is kept at a low but effective abrasive content level, hydroquinone is added in a moderate amount, and pyridine carboxylic acid and D-sorbitol are added in a basic amount, so that the system has a balanced ability to remove oxide layers, suppress silicon nitride layers, and control trench depressions.

[0019] Example 2 This embodiment investigates the effect of reducing the hydroquinone content on the system performance. In this embodiment, the polishing solution, by total mass, comprises 0.25 wt% CeO2, 0.0138 wt% hydroquinone, 0.05 wt% pyridinecarboxylic acid, 0.10 wt% D-sorbitol, and 0.001 wt% 1,2-benzisothiazolin-3-one, and the pH of the system is 4.0.

[0020] Compared to Example 1, this example only reduced the amount of hydroquinone added, while keeping the other components and pH value the same. This setting was used to investigate the effects of the polishing slurry on the oxide layer removal rate, silicon nitride layer removal rate, and overall selectivity when the amount of abrasive activity modifier added was low, and to observe its correlation with the maintenance of the subsequent trench morphology.

[0021] Example 3 This embodiment investigates the effect of increasing the pyridine carboxylic acid content on the inhibition effect and overall selectivity of the silicon nitride layer. In this embodiment, the polishing slurry, by total mass, includes 0.25 wt% CeO2, 0.0275 wt% hydroquinone, 0.15 wt% pyridine carboxylic acid, 0.10 wt% D-sorbitol, and 0.001 wt% 1,2-benzisothiazolin-3-one, and the pH of the system is 4.0.

[0022] Compared to Example 1, this example only increases the amount of pyridinecarboxylic acid added. The purpose of this setting is to highlight the role of the silicon nitride inhibitor in the system, observe its effect on the removal rate of the Si3N4 layer, and further investigate whether the material selectivity is improved under the condition that the oxide layer removal capacity is basically maintained.

[0023] Example 4 This embodiment investigates the effect of increasing the D-sorbitol content on the control of oxide depressions in the groove region. In this embodiment, the polishing slurry, by total mass, comprises 0.25 wt% CeO2, 0.0275 wt% hydroquinone, 0.05 wt% pyridinecarboxylic acid, 0.15 wt% D-sorbitol, and 0.001 wt% 1,2-benzisothiazolin-3-one, and the pH of the system is 4.0.

[0024] Compared to Example 1, this example only increased the amount of D-sorbitol. This setting was used to focus on investigating the changes in the planarization performance of the polishing slurry on the STI pattern structure after the increase of the groove depression inhibition component, while also observing its impact on the overall removal rate and selectivity.

[0025] Example 5 This embodiment is used to investigate the changes in system performance after increasing the hydroquinone content. In this embodiment, the polishing solution, by total mass, includes 0.25 wt% CeO2, 0.0388 wt% hydroquinone, 0.05 wt% pyridinecarboxylic acid, 0.10 wt% D-sorbitol, and 0.001 wt% 1,2-benzisothiazolin-3-one, and the pH of the system is 4.0.

[0026] Compared to Example 1, this example only increases the amount of hydroquinone added. This setting is used to examine whether, when the amount of oxide removal rate regulating component added is too high, the system will experience a further enhancement in oxide layer removal capacity, but a decrease in selectivity or a deterioration in trench region morphology control, thus demonstrating that hydroquinone needs to be controlled within a reasonable range.

[0027] Example 6 This embodiment is used to investigate the stability of the polishing slurry's performance when the system pH value is increased to near the upper limit of the acidic range. In this embodiment, the polishing slurry, by total mass, includes 0.25 wt% CeO2, 0.0275 wt% hydroquinone, 0.05 wt% pyridinecarboxylic acid, 0.10 wt% D-sorbitol, and 0.001 wt% 1,2-benzisothiazolin-3-one, and the system pH value is 5.0.

[0028] Compared to Example 1, this example only changed the pH value, while keeping other components unchanged. This setting was used to verify the process compatibility of the system of the present invention after shifting the pH value upward, and to examine whether the polishing slurry can still maintain a high selectivity and planarization efficiency near the upper limit of the acidic range.

[0029] Example 7 This embodiment is used to investigate the stability of the polishing slurry's performance when the system pH value is reduced to near the lower limit of the acidic range. In this embodiment, the polishing slurry, by total mass, comprises 0.25 wt% CeO2, 0.0275 wt% hydroquinone, 0.05 wt% pyridinecarboxylic acid, 0.10 wt% D-sorbitol, and 0.001 wt% 1,2-benzisothiazolin-3-one, and the system pH value is 3.0.

[0030] Compared with Example 1, this example only adjusts the pH value to a lower level to verify the applicability of the system of the present invention near the lower limit of the acid range, and to observe whether the removal rate, selectivity and trench morphology control are maintained at a good level.

[0031] Comparative Example 1 This comparative example illustrates the polishing performance of a basic cerium oxide slurry without the introduction of key functional components. In this comparative example, the polishing solution, by total mass, comprises 0.25 wt% CeO2 and 0.001 wt% 1,2-benzisothiazolin-3-one, the system pH is 4.0, and it is free of hydroquinone, pyridinecarboxylic acid, and D-sorbitol.

[0032] This comparative example only retains the basic abrasive and sterilization stabilizing components, and does not have the targeted configurations for adjusting the oxide layer removal rate, suppressing the silicon nitride layer, and controlling trench depressions, in order to reflect the polishing level of the basic cerium oxide slurry itself.

[0033] Comparative Example 2 This comparative example illustrates the performance of a system when only hydroquinone is added, without pyridinecarboxylic acid and D-sorbitol. In this comparative example, the polishing solution, by total mass, includes 0.25 wt% CeO2, 0.0275 wt% hydroquinone, and 0.001 wt% 1,2-benzisothiazolin-3-one, and the pH of the system is 4.0.

[0034] This comparative example only has the function of adjusting the oxide layer removal rate, but does not have the ability to suppress silicon nitride layer and control trench depression. It is used to illustrate that the introduction of hydroquinone alone is not enough to make the system achieve a high selectivity and planarization effect.

[0035] Comparative Example 3 This comparative example illustrates the system performance when hydroquinone and D-sorbitol are added without pyridinecarboxylic acid. In this comparative example, the polishing solution, by total mass, comprises 0.25 wt% CeO2, 0.0275 wt% hydroquinone, 0.10 wt% D-sorbitol, and 0.001 wt% 1,2-benzisothiazolin-3-one, and the pH of the system is 4.0.

[0036] This comparative example has the functions of adjusting the oxide layer removal rate and controlling trench depression, but it lacks silicon nitride suppression components, which is used to illustrate that the system's ability to protect the Si3N4 layer is still insufficient when pyridine carboxylic acid is absent.

[0037] Comparative Example 4 This comparative example illustrates the system performance when hydroquinone and pyridinecarboxylic acid are added, but D-sorbitol is not. In this comparative example, the polishing solution, by total mass, comprises 0.25 wt% CeO2, 0.0275 wt% hydroquinone, 0.05 wt% pyridinecarboxylic acid, and 0.001 wt% 1,2-benzisothiazolin-3-one, and the pH of the system is 4.0.

[0038] This comparative example possesses the ability to regulate oxide layer removal rate and suppress silicon nitride layer, but lacks trench depression control components. This illustrates that even if the system has a certain selectivity improvement effect, the ability to maintain the morphology of the STI trench region is still insufficient if D-sorbitol is lacking.

[0039] Test case To verify the performance of the polishing slurries prepared in the embodiments and comparative examples of the present invention in STI structural chemimechanical planarization, the removal rate, material selectivity, and step height change of each polishing slurry were tested. The same equipment and process conditions were used for each test case to ensure the comparability of the test results.

[0040] Test Example 1: TEOS Removal Rate vs. Si3N4 Removal Rate Test 12-inch oxide blank wafers and 12-inch Si3N4 blank wafers were used as test samples. Before testing, the film thickness of each sample before polishing was measured. Subsequently, polishing was performed under the same process conditions using the polishing solution of the corresponding embodiment or comparative example. After polishing, the samples were cleaned and dried, and the film thickness after polishing was measured.

[0041] The polishing equipment used was a Universal-300T chemical mechanical polisher; the polishing disc speed (Ps) was set to 93 rpm; the polishing head speed (Hs) was set to 87 rpm; the polishing pressure (DF) was set to 3.0 psi; the polishing fluid flow rate (SF) was set to 200 mL / min; and the polishing pad was IC1010. The film removal rate was calculated by dividing the difference in film thickness before and after polishing by the polishing time, in units of... / min.

[0042] TEOS: The Si3N4 selectivity ratio is calculated as the ratio of the TEOS removal rate to the Si3N4 removal rate.

[0043] The test results of each embodiment and comparative example, obtained according to the above method, are shown in Table 1 below: Table 1: TEOS removal rate, Si3N4 removal rate and selectivity of each embodiment and comparative example

[0044] Test Example 2: Step Height Test of STI Patterned TEOS Wafer A 12-inch STI patterned TEOS wafer was used as a test sample. Under the same polishing equipment and process conditions as in Test Example 1, the polishing fluids of Examples 1 to 7 were used for polishing. The step height change between the groove area and the surrounding planar area of ​​the sample was measured at 30 seconds, 60 seconds and 90 seconds of polishing.

[0045] The step height was measured using a Bruker probe profilometer, and the unit is 1. The test results are shown in Table 2 below: Table 2: Step height variation of each embodiment at different polishing times

[0046] Test Example 3: Result Comparison and Analysis As shown in Test Example 1, when only basic cerium oxide slurry was used in Comparative Example 1, the TEOS removal rate was only 2947. The Si3N4 removal rate reached 251 / min. / min, with a selectivity of only 11.7, indicates that a simple basic abrasive system is insufficient to meet the high selective polishing requirements of STI structures.

[0047] In Comparative Example 2, the TEOS removal rate increased to 4832 after the introduction of hydroquinone. / min, indicating that hydroquinone is beneficial for improving the removal capacity of the oxide layer; however, its Si3N4 removal rate is still as high as 276 The selectivity was only 17.5 / min, indicating that adding hydroquinone alone was insufficient to establish an effective protective relationship for the Si3N4 layer.

[0048] After adding D-sorbitol to Comparative Example 3, the selectivity increased to 25.9, indicating that D-sorbitol has a promoting effect on system planarization and morphology control; however, due to the lack of pyridine carboxylic acid, the removal rate of the Si3N4 layer was still too high, and the overall selectivity was still not ideal.

[0049] In Comparative Example 4, when pyridine carboxylic acid was introduced without D-sorbitol, the selectivity increased to 36.8, indicating that pyridine carboxylic acid has a significant effect on reducing the removal rate of the Si3N4 layer; however, compared with the embodiments of the present invention, it is still difficult to simultaneously achieve both high selectivity and excellent morphology control.

[0050] A comparison of Examples 1, 2, and 5 shows that the amount of hydroquinone added needs to be controlled within an appropriate range; when the hydroquinone content increases from 0.0138 wt% to 0.0275 wt%, the TEOS removal rate increases from 5244... / min increased to 5612 The Si3N4 removal rate was 90 / min. / min decreased to 83 / min, the selectivity increased from 58.2 to 67.6, indicating that a moderate hydroquinone content is beneficial to the overall performance balance; however, when it was further increased to 0.0388wt%, although the TEOS removal rate increased to 5791 / min, but the Si3N4 removal rate increased to 114 / min, the selection ratio dropped to 50.8, and the 90-second step height increased to 327. This indicates that more hydroquinone is not necessarily better; excessive amounts can weaken the control over the morphology of the trench area.

[0051] A comparison between Example 1 and Example 3 shows that increasing the pyridine carboxylic acid content reduces the Si3N4 removal rate from 83%. / min decreased to 75 / min, the selection ratio increased from 67.6 to 71.5, and the 90-second step height increased from 229 Dropped to 192 This indicates that appropriately increasing the amount of pyridine carboxylic acid is beneficial for further enhancing the protection of the barrier layer and improving the planarization state.

[0052] A comparison between Example 1 and Example 4 shows that increasing the D-sorbitol content maintained a high selectivity ratio, while the 90-second step height was 218. This indicates that increasing the D-sorbitol content has a more significant effect on controlling oxide loss in the trench area.

[0053] A comparison of Examples 1, 6, and 7 shows that when the pH values ​​are 4.0, 5.0, and 3.0, respectively, the selectivity of the system is 67.6, 62.9, and 60.7, respectively, and the 90-second step height is 229. 243 and 259 This indicates that the polishing solution described in this invention can maintain good selectivity and leveling performance in the pH range of 3 to 5, with a more balanced overall effect at a pH of 4.0.

[0054] In this embodiment, : Angstrom - unit of length; DF: pressure applied during CMP process, psi; Ps: polishing disc rotation speed of polishing equipment, rpm (revolutions per minute); Hs: polishing head rotation speed, rpm (revolutions per minute); SF: flow rate of polishing slurry composition, ml / min; TEOS: tetraethyl orthosilicate, used to fill trenches by chemical vapor deposition (CVD) to achieve electrical isolation between components; TEOS: Si3N4 selectivity: (TEOS removal rate) / (Si3N4 removal rate); Step height: The height difference between the medium material in the trench area and the surrounding planar area.

[0055] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any person skilled in the art can easily conceive of various variations or substitutions within the technical scope disclosed in the present invention, and these should all be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A cerium oxide-based polishing slurry for STI structures, characterized in that, Based on a percentage of the total mass of the polishing fluid, it includes: The polishing solution contains 0.05wt%–5wt% nano-cerium dioxide abrasive, 0.02wt%–0.2wt% hydroquinone, 0.05wt%–0.25wt% pyridinecarboxylic acid, 0.01wt%–0.5wt% D-sorbitol, and 0.001wt%–0.01wt% 1,2-benzisothiazolin-3-one, with a pH of 3–5.

2. The cerium oxide-based polishing solution for STI structures according to claim 1, wherein The average particle size of the nano-cerium dioxide abrasive is 100 nm; the content of the nano-cerium dioxide abrasive is 0.25 wt%.

3. The cerium oxide based polishing solution for STI structures according to claim 1, wherein The reducing agent is a compound with at least two hydroxyl groups on its aromatic ring.

4. The cerium oxide-based polishing slurry for STI structures according to claim 1, characterized in that, The two hydroxyl groups in the reducing agent are located in the ortho, meta, or para positions.

5. The cerium oxide-based polishing solution for STI structures according to claim 1, wherein The reducing agent is selected from one or more of hydroquinone, catechol, resorcinol, pyrogallol, 2-methylhydroquinone, tert-butylhydroquinone, 2,5-di-tert-butylhydroquinone, 1,4-naphthol, 1,4-anthraquinone and their alkyl-substituted derivatives.

6. The cerium oxide-based polishing slurry for STI structures according to claim 1, characterized in that, The reducing agent is hydroquinone, and the content of hydroquinone is 0.0138 wt% to 0.0388 wt%.

7. The cerium oxide-based polishing slurry for STI structures according to claim 1, characterized in that, The content of pyridinecarboxylic acid is 0.05wt% to 0.15wt%.

8. The cerium oxide-based polishing solution for STI structures according to claim 1, wherein The content of D-sorbitol is 0.10wt% to 0.15wt%, the content of 1,2-benzisothiazolin-3-one is 0.001wt%, and the pH value of the polishing solution is 4.

0.

9. The application of the cerium oxide-based polishing slurry according to any one of claims 1 to 8 in the chemical mechanical planarization of STI structures.

10. Use according to claim 9, characterized in that, The STI structure includes a TEOS oxide layer and a Si3N4 layer.

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