Chemical mechanical polishing solution

Abstract

This invention discloses a chemical mechanical polishing (CMP) slurry, comprising silica abrasive particles and an accelerator; wherein the accelerator is selected from pyridine compounds, piperidine compounds, pyrrolidine compounds, or pyrrole compounds and their derivatives containing one or more carboxyl groups, and pyrimidine compounds and their derivatives containing one or more amino groups. The acidic CMP slurry provided by this invention can improve the silicon nitride removal rate while simultaneously increasing the polishing rate of polycrystalline silicon.

Description

Technical Field

[0001] This invention relates to the field of chemical mechanical polishing slurries, and more particularly to a chemical mechanical polishing slurry for silicon nitride and polycrystalline silicon. Background Technology

[0002] In integrated circuit fabrication, silicon nitride is typically used as a barrier layer or etch stop layer to protect the underlying structure. Therefore, in semiconductor device production, almost every stage requires the removal of the silicon nitride layer; for example, the barrier layer needs to be removed during the formation of the element separation structure. However, the polishing rate requirements for silicon nitride vary at different stages of the semiconductor fabrication process.

[0003] When using silicon nitride as a barrier layer, it's often necessary to polish other materials on the barrier layer first, requiring the polishing to stop at the barrier layer. Therefore, most polishing slurries aim to reduce the silicon nitride removal rate while achieving a relatively high removal rate for other materials. For example, in shallow trench isolation (STI) processes, where silicon nitride is used as the termination layer, the CMP polishing slurry needs to have a high silicon dioxide removal rate and a low silicon nitride removal rate. However, in point-of-open (POP) processes, a high silicon nitride removal rate and a low polysilicon removal rate are required.

[0004] For example, patent CN102199399A proposes a polishing slurry that can be used to polish silicon nitride, which contains water, abrasive, and alkyl aryl polyether sulfonic acid compound. The polishing slurry has a selectivity of ≥5:1 for silicon oxide / polycrystalline silicon and a selectivity of ≥5:1 for silicon nitride / polycrystalline silicon.

[0005] CN102201337A discloses a polishing slurry comprising water, abrasive, and acyclic organic sulfonic acid compound, exhibiting a selectivity of ≥2:1 for silicon oxide / polycrystalline silicon and ≥2:1 for silicon nitride / polycrystalline silicon.

[0006] However, with the development of semiconductor manufacturing processes, some emerging semiconductor technologies require non-selective polishing slurries, where both silicon nitride and polysilicon have relatively fast removal rates. However, products for this type of polishing slurry are currently scarce in the market. Summary of the Invention

[0007] To address the aforementioned deficiencies, this invention provides an acidic chemical mechanical polishing slurry that, under conditions of using abrasive particles with a low concentration, significantly improves the polishing speed of silicon nitride and polycrystalline silicon by using one or more of pyridine compounds, piperidine compounds, pyrrolidine compounds or pyrrole compounds and their derivatives containing one or more carboxyl groups, as well as pyrimidine compounds containing one or more amino groups.

[0008] The present invention provides a chemical mechanical polishing slurry, the chemical mechanical polishing slurry comprising silica abrasive particles and an accelerator; wherein the accelerator is selected from pyridine compounds, piperidine compounds, pyrrolidine compounds or pyrrole compounds and their derivatives containing one or more carboxyl groups, and pyrimidine compounds and their derivatives containing one or more amino groups.

[0009] Preferably, the concentration of the silica particles is 1% to 15% by mass, more preferably 1% to 10%.

[0010] Preferably, the pyridine compound, piperidine compound, pyrrolidine compound, or pyrrole compound and its derivatives containing one or more carboxyl groups are selected from one or more of 2-carboxypyridine, 3-carboxypyridine, 4-carboxypyridine, 2,3-dicarboxypyridine, 2,4-dicarboxypyridine, 2,6-dicarboxypyridine, 3,5-dicarboxypyridine, 2-carboxypiperidine, 3-carboxypiperidine, 4-carboxypiperidine, 2,3-dicarboxypiperidine, 2,4-dicarboxypiperidine, 2,6-dicarboxypiperidine, 3,5-dicarboxypiperidine, 2-carboxypyrrolidine, 3-carboxypyrrolidine, 2,4-dicarboxypyrrolidine, 2,5-dicarboxypyrrolidine, 2-carboxypyrrole, 3-carboxypyrrole, 2,5-dicarboxypyrrole, and 3,4-dicarboxypyridine.

[0011] Preferably, the concentration of the pyridine compound, piperidine compound, pyrrolidine compound or pyrrole compound and its derivatives containing one or more carboxyl groups is 0.01 to 1% by mass, more preferably 0.05 to 0.6%.

[0012] Preferably, the amino pyrimidine compound and its derivatives are selected from one or more of 2-aminopyrimidine, 4-aminopyrimidine, 2,4-diaminopyrimidine, 2,4,5-triaminopyrimidine and their derivatives.

[0013] Preferably, the concentration of the pyrimidine compound containing one or more amino groups and its derivatives is 0.01% to 1% by mass, more preferably 0.02% to 0.6%.

[0014] Preferably, the pH value of the chemical mechanical polishing solution is 2-6.

[0015] Preferably, the chemical mechanical polishing fluid further includes a pH adjuster and / or a bactericide.

[0016] Preferably, the pH adjuster includes one or more of HNO3, KOH, phosphoric acid, K2HPO4, or KH2PO4.

[0017] Preferably, the bactericide is selected from one or more of 5-chloro-2-methyl-4-isothiazolin-3-one (CIT), 2-methyl-4-isothiazolinone (MIT), 1,2-phenylpropionisothiazolinone (BIT), iodopropynyl carbamate (IPBC), and 1,3-dihydroxymethyl-5,5-methylhydantoin (DMDMH).

[0018] Compared with the prior art, the technical advantages of the present invention are:

[0019] 1) This invention provides an acidic chemical mechanical polishing fluid;

[0020] 2) This invention improves the silicon nitride removal rate while simultaneously increasing the polishing rate of polycrystalline silicon. Detailed Implementation

[0021] The present invention will be further illustrated by way of embodiments below, but the present invention is not limited to the scope of the embodiments described herein.

[0022] The polishing solution formulated according to Table 1 was tested under the following experimental conditions.

[0023] Specific polishing conditions: LK machine, IC1010pad, speed 93 / 87. Polishing pressure: 3.0psi. Polishing flow rate: 300ml / min. Input the above parameters into the LK machine, polish 12-inch silicon nitride and polysilicon for 1 minute, clean, dry, inspect, and obtain the polishing results.

[0024] Table 1 compares the formulations and polishing effects of polishing slurries 1-2 and the polishing slurries 1-8 of the present invention.

[0025]

[0026]

[0027] As shown in Table 1, the addition of pyridine, piperidine, pyrrolidine, or pyrrole compounds with carboxyl groups significantly improved the removal rate of silicon nitride. The results from Comparative Example 2 and Examples 1-8 show that the addition of pyrimidine compounds significantly improved the removal rate of polycrystalline silicon. Compared to Comparative Examples 1-2, Examples 1-8, by simultaneously adding carboxyl and pyrimidine compounds, at pH 2-6, demonstrated that the polishing solution could improve both the silicon nitride removal rate and the polycrystalline silicon polishing rate.

[0028] It should be noted that the embodiments of the present invention have better practicability and do not impose any form of limitation on the present invention. Any technician familiar with the field may use the technical content disclosed above to change or modify it into an equivalent effective embodiment. However, any modification or equivalent changes and modifications made to the above embodiments based on the technical essence of the present invention without departing from the content of the technical solution of the present invention are still within the scope of the technical solution of the present invention.

Claims

1. A chemical mechanical polishing slurry, characterized in that, The chemical mechanical polishing slurry includes silica abrasive particles and an accelerator; wherein the accelerator is selected from pyridine compounds, piperidine compounds, pyrrolidine compounds or pyrrole compounds containing one or more carboxyl groups, and pyrimidine compounds containing one or more amino groups; The pyridine compound, piperidine compound, pyrrolidine compound, or pyrrole compound containing one or more carboxyl groups is selected from one or more of 2-carboxypyridine, 3-carboxypyridine, 4-carboxypyridine, 2,3-dicarboxypyridine, 2,4-dicarboxypyridine, 2,6-dicarboxypyridine, 3,5-dicarboxypyridine, 2-carboxypiperidine, 3-carboxypiperidine, 4-carboxypiperidine, 2,3-dicarboxypiperidine, 2,4-dicarboxypiperidine, 2,6-dicarboxypiperidine, 3,5-dicarboxypiperidine, 2-carboxypyrrolidine, 3-carboxypyrrolidine, 2,4-dicarboxypyrrolidine, 2,5-dicarboxypyrrolidine, 2-carboxypyrrole, 3-carboxypyrrole, 2,5-dicarboxypyrrole, and 3,4-dicarboxypyridine. The concentration of the pyridine compound, piperidine compound, pyrrolidine compound, or pyrrole compound containing one or more carboxyl groups is 0.05 to 0.6% by mass. The pyrimidine compound containing one or an amino group is selected from one or more of 2-aminopyrimidine, 4-aminopyrimidine, 2,4-diaminopyrimidine, and 2,4,5-triaminopyrimidine; The concentration of the pyrimidine compound containing one or more amino groups is 0.02-0.6% by mass; the pH value of the chemimechanical polishing solution is 2-6.

2. The chemical mechanical polishing slurry as described in claim 1, characterized in that, The concentration of the silica particles is 1-15% by mass.

3. The chemical mechanical polishing slurry as described in claim 2, characterized in that, The mass percentage concentration of the silica particles is 1-10%.

Images