High-speed and low-defect silicon medium polishing liquid

Abstract

The invention relates to the technical field of silicon wafer polishing, in particular to a high-speed and low-defect silicon medium polishing liquid which comprises grinding particles, an alkaline compound, a surface protective agent and water. The content of the grinding particles is 4-10 wt%, the content of the alkaline compound is 0.05-1.5 wt%, the content of the surface protective agent is 0.1-3 wt%, and the balance is water; the alkali compound is at least one of tetramethylammonium hydroxide, piperazine, 1-(2-aminoethyl) piperazine, 1, 4-bis (3-aminopropyl) piperazine, 1, 4-bis (2-hydroxyethyl) piperazine, 1, 8-diazabicyclo (5, 4, 0) undec-7-ene, 4-aminopiperidine, monoethanolamine, 3-amino-1-propanol, n-propylamine, isopropylamine, diglycolamine, isopropanolamine, ethylenediamine, choline hydroxide and ammonia water. By adding the organic base with a special molecular structure and adjusting the concentration ratio of the organic base to the surface protecting agent, the high removal rate can be effectively achieved under the high dilution ratio, and the good surface quality without polishing marks / fog, with few particle defects and low roughness is obtained.

Description

Technical Field

[0001] The invention relates to the technical field of silicon wafer polishing, in particular to a silicon polishing liquid with high speed and low defects. Background Art

[0002] With the development of the semiconductor industry, the requirements for the surface quality of silicon wafers after polishing are getting higher and higher. In order to improve the polishing efficiency and obtain good surface quality, a silicon intermediate polishing step is usually added between the silicon rough polishing step and the silicon fine polishing step. For advanced processes, the silicon wafer intermediate polishing is required to have a higher removal rate, and the surface after polishing is free of polishing marks / fog, few particle defects and low surface roughness. The silicon intermediate polishing liquid is usually required to obtain a removal rate that is much higher than that of the silicon fine polishing but slightly lower than that of the silicon rough polishing liquid at a high dilution ratio, so as to quickly repair the rough surface of the silicon after rough polishing, which can effectively reduce production costs. Therefore, it is particularly necessary to provide a fine polishing liquid that can effectively reduce the friction coefficient between the silicon wafer surface and the polishing pad to meet the requirements of advanced processes. Summary of the Invention

[0003] The present invention solves the problems in the related art and proposes a silicon polishing liquid with high rate and low defects. By adding an organic base with a special molecular structure and adjusting the concentration ratio of the organic base to the surface protective agent, a higher removal rate can be effectively achieved at a high dilution ratio, and good surface quality with no polishing marks / fog, few particle defects and low roughness can be obtained.

[0004] In order to solve the above technical problems, the present invention is achieved through the following technical solutions: a high-rate and low-defect silicon polishing liquid, comprising abrasive particles, an alkaline compound, a surface protective agent and water; the content of the abrasive particles is 4-10wt%, preferably 8-10wt%; the content of the alkaline compound is 0.05-1.5wt%; the content of the surface protective agent is 0.1-3wt%, preferably 0.05-5wt%, more preferably 0.1-3wt%; the balance is water;

[0005] The alkaline compound is at least one of tetramethylammonium hydroxide (TMAH), piperazine, 1-(2-aminoethyl)piperazine (AEP), 1,4-bis(3-aminopropyl)piperazine, 1,4-bis(2-hydroxyethyl)piperazine, 1,8-diazabicyclo(5,4,0)undec-7-ene (DBU), 4-aminopiperidine, monoethanolamine (MEA), 3-amino-1-propanol (3A1P), n-propylamine, isopropylamine, diglycolamine, isopropanolamine, ethylenediamine, choline hydroxide, and ammonia water.

[0006] As a preferred embodiment, the abrasive particles are nano-colloidal silica.

[0007] As a preferred embodiment, the surface protective agent is at least one of polyvinyl alcohol (PVA), glycerol, pullulan, hydroxyethyl cellulose (HEC), AEO-3, AEO-9, PEO-PPO-PPEO (PE6800), and polyacrylamide.

[0008] As a preferred solution, the primary particle size of the nano-colloidal silica is 10-60 nm, preferably 20-50 nm, and more preferably 30-40 nm.

[0009] As a preferred solution, the pH of the silicon polishing solution is 10.0-11.0.

[0010] Compared with the prior art, the beneficial effects of the present invention are: the silicon polishing liquid of the present invention can effectively achieve a higher removal rate at a high dilution ratio by adding an organic base with a special molecular structure and adjusting the concentration ratio of the organic base to the surface protective agent, and obtain good surface quality with no polishing marks / mist, few particle defects and low roughness. DETAILED DESCRIPTION

[0011] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only some embodiments of the present invention, rather than all embodiments. The following description of at least one exemplary embodiment is actually only illustrative and is in no way intended to limit the present invention and its application or use. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0012] Unless otherwise specifically stated, the numerical value set forth in these embodiments does not limit the scope of the present invention. Technology and methods known to those of ordinary skill in the relevant art may not be discussed in detail, but in appropriate cases, the technology and methods should be considered as a part of the specification. In all examples shown and discussed here, any specific value should be interpreted as merely exemplary, rather than as a limitation. Therefore, other examples of exemplary embodiments can have different values.

[0013] In the following examples, the experimental methods without specific conditions are generally measured according to national standards; if there is no corresponding national standard, the general standard requirements or general methods are used.

[0014] In all the following examples and comparative examples, the amount of the alkaline compound added was determined by adjusting the pH of the intermediate polishing solution to 10.8.

[0015] Table 1 Material dosage and types of each embodiment and comparative example

[0016]

[0017]

[0018] Application Example 1

[0019] Polishing process:

[0020] Polishing machine: Huahai Qingke (U300B)

[0021] Polishing pressure: RR / Z1 / Z2 / Z3 / Z4 / Z5=5.25 / 4 / 2.3 / 2.15 / 0 / 2

[0022] Blasting head speed: 87rpm

[0023] Throwing disk speed: 93rpm

[0024] Dilution ratio: Slurry: DIW = 1L: 50L

[0025] Polishing liquid flow rate: 300ml / min

[0026] Polishing pad: FUJIBO 275NX

[0027] Polished wafer: thickness 725μm, P type (100), resistivity > 100Ω, diameter 200mm

[0028] Polishing temperature: 28℃-32℃

[0029] Polishing time: 30min

[0030] Cleaning conditions: A cleaning solution (SC-1 cleaning solution) was prepared by mixing ammonia (29 wt % concentration): hydrogen peroxide (31 wt % concentration): deionized water in a ratio of 1:3:30 (volume ratio) to clean the polished silicon wafer surface.

[0031] Table 2 Comparison of test results after CMP of each embodiment and each comparative example

[0032]

[0033]

[0034] Comparing Examples 1-3 with Examples 6-7, it can be seen that increasing the concentration of the surface protectant added to the polishing solution will reduce the removal rate, but it is beneficial to reduce the surface roughness of the silicon wafer. In addition, the removal rate of the silicon wafer is related to the type of alkaline compound, among which DBU has a stronger alkalinity and can achieve a higher removal rate. Comparing the various examples and comparative examples, it can be seen that the number of particle defects on the silicon wafer surface is related to both the type of alkaline compound and the concentration of the surface protectant. When the alkaline compound with a cyclic molecular structure is compounded with a polymer surface protectant, and when the surface protectant concentration is between 2.12-2.20wt%, it is easier to obtain lower particle defects.

[0035] The above are preferred embodiments of the present invention. Those skilled in the art to which the present invention belongs can also change and modify the above embodiments. Therefore, the present invention is not limited to the above specific embodiments. Any obvious improvements, replacements or modifications made by those skilled in the art on the basis of the present invention fall within the scope of protection of the present invention.

Claims

1. A silicon polishing solution with high rate and low defects, characterized by: The invention comprises abrasive particles, an alkaline compound, a surface protective agent and water; the content of the abrasive particles is 4-10wt%, the content of the alkaline compound is 0.05-1.5wt%, the content of the surface protective agent is 0.1-3wt%, and the balance is water; The alkaline compound is at least one of tetramethylammonium hydroxide, piperazine, 1-(2-aminoethyl)piperazine, 1,4-bis(3-aminopropyl)piperazine, 1,4-bis(2-hydroxyethyl)piperazine, 1,8-diazabicyclo(5,4,0)undec-7-ene, 4-aminopiperidine, monoethanolamine, 3-amino-1-propanol, n-propylamine, isopropylamine, diglycolamine, isopropanolamine, ethylenediamine, choline hydroxide, and ammonia water.

2. The high-rate, low-defect silicon polishing solution according to claim 1, characterized in that: The abrasive particles are nano-colloidal silica.

3. The high-rate and low-defect silicon polishing solution according to claim 1, characterized in that: The surface protective agent is at least one of polyvinyl alcohol, glycerol, pullulan, hydroxyethyl cellulose, AEO-3, AEO-9, PEO-PPO-PPEO, and polyacrylamide.

4. The high-rate, low-defect silicon polishing solution according to claim 2, characterized in that: The primary particle size of the nano-colloidal silica is 10-60 nm.

5. The high-rate and low-defect silicon polishing solution according to claim 4, characterized in that: The primary particle size of the nano-colloidal silica is 20-50 nm.

6. The high-rate and low-defect silicon polishing solution according to claim 5, characterized in that: The primary particle size of the nano-colloidal silica is 30-40 nm.

7. The high-rate and low-defect silicon polishing solution according to claim 1, characterized in that: The pH of the silicon bath is 10.0-11.

0.

8. The high-rate and low-defect silicon polishing solution according to claim 1, characterized in that: The content of the abrasive particles is 8-10 wt %.

9. The high-rate and low-defect silicon polishing solution according to claim 1, characterized in that: The content of the surface protective agent is 0.05-5 wt%.

10. The high-rate and low-defect silicon polishing solution according to claim 9, characterized in that: The content of the surface protecting agent is 0.1-3 wt %.

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