Fine polishing liquid for reducing surface friction coefficient of silicon wafer

Abstract

The invention relates to the technical field of chemical mechanical polishing, in particular to fine polishing liquid for reducing the surface friction coefficient of a silicon wafer, which comprises the following components in parts by weight: 4-10 parts of grinding particles; 0.3 to 1.5 parts of an alkaline compound; 0.1-3 parts of a friction force regulator; the total part number is 100, and the balance is water. Wherein the friction force regulator is selected from at least one of a water-soluble cellulose compound, a water-soluble fatty alcohol / alcohol compound, a water-soluble polyether compound and a water-soluble amide compound. According to the fine polishing liquid for reducing the surface friction coefficient of the silicon wafer, the friction coefficient between the surface of the silicon wafer and a polishing pad can be effectively reduced through the synergistic effect of the introduced friction force regulator, the grinding particles and the alkaline compound, and therefore the good surface quality which is free of polishing marks / fog, few in particle defect and low in roughness is obtained.

Description

Technical Field

[0001] The invention relates to the technical field of chemical mechanical polishing, in particular to a fine polishing liquid for reducing the friction coefficient of a silicon wafer surface. 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. Silicon polishing liquid is used in the last step of silicon wafer polishing, and its quality requirements are extremely high. For advanced processes, it is required that the surface of the silicon wafer after polishing should be free of polishing marks / fog, with few particle defects and low surface roughness. However, in the chemical mechanical polishing process, the use of existing polishing liquid, under the action of mechanical friction, can easily cause defects such as polishing marks / fog and particle contamination on the surface of the silicon wafer, and at the same time increase the surface roughness. Therefore, there is an urgent need for a 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 object of the present invention is to provide a fine polishing liquid capable of reducing the friction coefficient of the silicon wafer surface, thereby obtaining a silicon wafer surface with low particle defects and surface roughness while being free of polishing marks / fog.

[0004] The technical solution adopted by the present invention to solve the technical problem is:

[0005] A fine polishing liquid for reducing the friction coefficient of a silicon wafer surface comprises the following components in parts by weight:

[0006] 4-10 parts of abrasive particles;

[0007] 0.3-1.5 parts of basic compound;

[0008] Friction regulator 0.1-3 parts;

[0009] The total number of parts is 100, and the rest is water;

[0010] The friction regulator is selected from at least one of water-soluble cellulose compounds, water-soluble fatty alcohol / alcohol compounds, water-soluble polyether compounds, and water-soluble amide compounds.

[0011] Optionally, the friction regulator includes water-soluble fatty alcohol / alcohol compounds, and at least one of water-soluble cellulose compounds, water-soluble polyether compounds, and water-soluble amide compounds.

[0012] Optionally, the water-soluble cellulose compound is selected from at least one of carboxymethyl cellulose, hydroxyethyl cellulose, methyl cellulose, hydroxymethyl cellulose and hydroxypropyl methyl cellulose.

[0013] Optionally, the water-soluble fatty alcohol / alcohol compound is selected from at least one of polyvinyl alcohol, polyethylene glycol, polyglycerol, AEO-3, AEO-7, and AEO-9.

[0014] Optionally, the water-soluble polyether compound is selected from at least one of polyoxypropylene glycerol ether, PGG-20, polyether F68, and polyether F127.

[0015] Optionally, the water-soluble amide compound is selected from at least one of polyacrylamide, acrylamide, polyacryloylmorpholine and acrylmoylmorpholine.

[0016] Optionally, the alkaline compound is selected from at least one of potassium hydroxide, tetramethylammonium hydroxide, piperazine, diethylenetriamine, 4-aminopiperidine and ammonia water.

[0017] Optionally, the abrasive particles are nano-colloidal silica.

[0018] Optionally, the primary particle size of the nano-colloidal silica is 30-40 nm.

[0019] Optionally, the pH of the polishing solution is 10.0-11.0.

[0020] The beneficial effects of the present invention are:

[0021] The fine polishing liquid for reducing the friction coefficient of the silicon wafer surface provided in the present application can effectively reduce the friction coefficient between the silicon wafer surface and the polishing pad through the synergistic effect of the introduced friction regulator, abrasive particles and alkaline compounds, thereby obtaining a good surface quality with no polishing marks / fog, few particle defects and low roughness. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] The present invention is further described below in conjunction with the accompanying drawings and embodiments.

[0023] Figure 1 It is a comparison chart of the friction coefficient of the fine polishing liquid in Example 1, Example 2 and Comparative Example 1 of the present invention. DETAILED DESCRIPTION

[0024] The present invention is now further described in detail. The embodiments described below are exemplary and intended to be used to explain the present invention, but cannot be understood as limiting the present invention. All other embodiments obtained by ordinary technicians in this field without creative work based on the embodiments of the present invention belong to the scope of protection of the present invention.

[0025] In order to effectively reduce the friction coefficient between the silicon wafer surface and the polishing pad to meet the requirements of advanced processes, the present application provides a fine polishing liquid for reducing the friction coefficient of the silicon wafer surface. The fine polishing liquid includes the following components in parts by weight:

[0026] 4-10 parts of abrasive particles;

[0027] 0.3-1.5 parts of basic compound;

[0028] Friction regulator 0.1-3 parts;

[0029] The total number of parts is 100, and the rest is water;

[0030] The friction regulator is selected from at least one of water-soluble cellulose compounds, water-soluble fatty alcohol / alcohol compounds, water-soluble polyether compounds, and water-soluble amide compounds.

[0031] The fine polishing liquid for reducing the friction coefficient of the silicon wafer surface provided in the present application can effectively reduce the friction coefficient between the silicon wafer surface and the polishing pad through the synergistic effect of the introduced friction regulator, abrasive particles and alkaline compounds, thereby obtaining a good surface quality with no polishing marks / fog, few particle defects and low roughness.

[0032] Specifically, in order to further improve the lubricity of the fine polishing liquid, the present application prefers that the friction regulator is a combination of at least two of water-soluble cellulose compounds, water-soluble fatty alcohol / alcohol compounds, water-soluble polyether compounds, and water-soluble amide compounds; further, the present application prefers that the friction regulator includes water-soluble fatty alcohol / alcohol compounds, and also includes at least one of water-soluble cellulose compounds, water-soluble polyether compounds, and water-soluble amide compounds.

[0033] Among them, the present application preferably selects at least one of the water-soluble cellulose compounds selected from carboxymethyl cellulose, hydroxyethyl cellulose, methyl cellulose, hydroxymethyl cellulose, and hydroxypropyl methyl cellulose; preferably selects at least one of the water-soluble fatty alcohol / alcohol compounds selected from polyvinyl alcohol, polyethylene glycol, polyglycerol, AEO-3, AEO-7, and AEO-9; preferably selects at least one of the water-soluble polyether compounds selected from polyoxypropylene glyceryl ether, PGG-20, polyether F68, and polyether F127; preferably selects at least one of the water-soluble amide compounds selected from polyacrylamide, acrylamide, polyacryloyl morpholine, and acrylloyl morpholine.

[0034] Furthermore, the present application preferably adds 0.1-3 parts by weight of the friction regulator to the fine polishing liquid, more preferably 0.3-1 parts, and even more preferably 0.4-0.8 parts.

[0035] The present application preferably uses an alkaline compound selected from at least one of potassium hydroxide, tetramethylammonium hydroxide, piperazine, diethylenetriamine, 4-aminopiperidine, and ammonia water, and the pH of the polishing solution is preferably 10.0-11.0.

[0036] To ensure the polishing quality, the present application preferably adds 4-10 parts of abrasive particles by weight, more preferably 8-10 parts; further, the abrasive particles are preferably nano-colloidal silica; and the primary particle size of the nano-colloidal silica is preferably 10-60nm, more preferably 20-50nm, and more preferably 30-40nm.

[0037] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, specific embodiments of the present invention are described in detail below with reference to the accompanying drawings.

[0038] The experimental methods in the following examples and comparative examples without specifying specific conditions are usually measured in accordance with national standards; if there is no corresponding national standard, the experimental methods are carried out in accordance with general standard requirements or general methods.

[0039] Unless otherwise specified, the primary particle size of the nano-colloidal silica in each of the embodiments and comparative examples of the present invention is 40 nm.

[0040] Example 1

[0041] According to the weight percentage, first weigh 89.7 parts of deionized water and add it to the stirring tank, start stirring, then weigh 0.3 parts of tetramethylammonium hydroxide, 0.5 parts of polyglycerol, and 0.05 parts of PGG-20 in turn and add them to the premixing tank, stir for 30 minutes, then weigh 0.45 parts of ammonia water and add it to the stirring tank, stir for 15 minutes, then weigh 9 parts of nano-colloidal silica and add them to the stirring tank, stir for 30 minutes to prepare the finished product.

[0042] Example 2

[0043] According to the weight percentage, 89.69 parts of deionized water were first weighed and added into a stirring kettle, and stirring was started. Then, 0.3 parts of tetramethylammonium hydroxide, 0.2 parts of hydroxyethyl cellulose, 0.05 parts of polyethylene glycol, 0.01 parts of AEO-9 and 0.3 parts of acryloyl morpholine were weighed in sequence and added into a premixing tank. After timed stirring for 30 minutes, 0.45 parts of ammonia water were weighed and added into the stirring kettle. Timed stirring was performed for 15 minutes. Then, 9 parts of nano-colloidal silica were weighed and added into the stirring kettle. Timed stirring was performed for 30 minutes to prepare a finished product.

[0044] Example 3

[0045] According to the weight percentage, first weigh 89.7 parts of deionized water and add it to the stirring kettle, start stirring, then weigh 0.3 parts of tetramethylammonium hydroxide, 0.5 parts of polyglycerol, and 0.05 parts of polyoxypropylene glycerol ether in turn and add them to the premixing tank, stir for 30 minutes, then weigh 0.45 parts of ammonia water and add it to the stirring kettle, stir for 15 minutes, then weigh 9 parts of nano-colloidal silica and add them to the stirring kettle, stir for 30 minutes to prepare the finished product.

[0046] Example 4

[0047] According to the weight percentage, 89.6 parts of deionized water were first weighed and added to the stirring kettle, and stirring was started. Then, 0.3 parts of tetramethylammonium hydroxide, 0.1 parts of 4-aminopiperidine, 0.5 parts of polyvinyl alcohol, and 0.05 parts of polyethylene glycol were weighed in sequence and added to the premixing tank. After timed stirring for 30 minutes, 0.45 parts of ammonia water were weighed and added to the stirring kettle. Timed stirring was performed for 15 minutes. Then, 9 parts of nano-colloidal silica were weighed and added to the stirring kettle. Timed stirring was performed for 30 minutes to prepare a finished product.

[0048] Comparative Example 1

[0049] According to the weight percentage, first weigh 90.25 parts of deionized water and add it to the stirring kettle, start stirring, then weigh 0.3 parts of tetramethylammonium hydroxide and 0.45 parts of ammonia water in sequence and add them to the stirring kettle, stir for 15 minutes, then weigh 9 parts of nano-colloidal silica and add them to the stirring kettle, stir for 30 minutes to prepare the finished product.

[0050] Comparative Example 2

[0051] According to the weight percentage, first weigh 90.14 parts of deionized water and add it to the stirring kettle, start stirring, then weigh 0.3 parts of tetramethylammonium hydroxide and 0.15 parts of polyether F68 in turn and add them to the premixing tank, stir for 30 minutes, then weigh 0.45 parts of ammonia water and add it to the stirring kettle, stir for 15 minutes, then weigh 9 parts of nano-colloidal silica and add them to the stirring kettle, stir for 30 minutes to prepare the finished product.

[0052] Application Example 1

[0053] Polishing process:

[0054] Polishing machine: Shanghai Zhiling polishing machine (CP-1280B / DP)

[0055] Polishing pressure: 125Kg

[0056] Blasting head speed: 29rpm

[0057] Throwing plate speed: 30rpm

[0058] Polishing liquid flow rate: 1.5L / min

[0059] Polishing pad: 7355-000FE (Chiyoda, Japan)

[0060] Polished wafer: thickness 725μm, P type (100), resistivity > 100Ω, diameter 200mm

[0061] Polishing temperature: 28℃-32℃

[0062] Polishing time: 7 minutes

[0063] Cleaning conditions: A cleaning solution (SC-1 cleaning solution) was prepared by mixing ammonia water (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.

[0064] The surface of the polished silicon wafer was tested, and the test results are shown in Table 1:

[0065] Table 1

[0066] Polishing marks / fog Particle defects (pcs) Surface roughness(nm) Example 1 none 8 1.1 Example 2 none 5 1.0 Example 3 none 10 1.1 Example 4 none 15 1.2 Comparative Example 1 have 4790 1.5 Comparative Example 2 have 568 1.4

[0067] The friction coefficient comparison diagram of the fine polishing liquid in Example 1, Example 2 and Comparative Example 1 is shown in Figure 1 As shown; By comparing Examples 1-4 with Comparative Example 1, it can be seen that when the friction modifier is added to the fine polishing liquid, the surface defects of the silicon wafer and the surface roughness can be greatly reduced. As shown in Comparative Example 2, when a single friction modifier is added to the fine polishing liquid at a low concentration, the surface defects and roughness of the silicon wafer cannot be effectively controlled. Therefore, when a certain concentration of effectively compounded friction modifier is added to the fine polishing liquid, the friction between the silicon wafer and the polishing pad can be effectively reduced, thereby effectively reducing the number of defects on the surface of the silicon wafer and reducing the surface roughness.

[0068] Based on the above ideal embodiments of the present invention, the relevant staff can make various changes and modifications without departing from the technical concept of the present invention through the above description. The technical scope of the present invention is not limited to the contents of the specification, and its technical scope must be determined according to the scope of the claims.

Claims

1. A fine polishing liquid for reducing the friction coefficient of a silicon wafer surface, characterized in that: According to parts by weight, it includes the following components: 4-10 parts of abrasive particles; 0.3-1.5 parts of basic compound; Friction regulator 0.1-3 parts; The total number of parts is 100, and the rest is water; The friction regulator is selected from at least one of water-soluble cellulose compounds, water-soluble fatty alcohol / alcohol compounds, water-soluble polyether compounds, and water-soluble amide compounds.

2. The fine polishing liquid for reducing the friction coefficient of the silicon wafer surface according to claim 1, characterized in that: The friction regulator includes water-soluble fatty alcohol / alcohol compounds and at least one of water-soluble cellulose compounds, water-soluble polyether compounds and water-soluble amide compounds.

3. The fine polishing liquid for reducing the friction coefficient of the silicon wafer surface according to claim 2, characterized in that: The water-soluble cellulose compound is selected from at least one of carboxymethyl cellulose, hydroxyethyl cellulose, methyl cellulose, hydroxymethyl cellulose and hydroxypropyl methyl cellulose.

4. The fine polishing liquid for reducing the friction coefficient of the silicon wafer surface according to claim 2, characterized in that: The water-soluble fatty alcohol / alcohol compound is selected from at least one of polyvinyl alcohol, polyethylene glycol, polyglycerol, AEO-3, AEO-7, and AEO-9.

5. The fine polishing liquid for reducing the friction coefficient of the silicon wafer surface as claimed in claim 2, characterized in that: The water-soluble polyether compound is selected from at least one of polyoxypropylene glycerol ether, PGG-20, polyether F68, and polyether F127.

6. The fine polishing liquid for reducing the friction coefficient of the silicon wafer surface according to claim 2, characterized in that: The water-soluble amide compound is at least one selected from polyacrylamide, acrylamide, polyacryloylmorpholine and acryloylmorpholine.

7. The fine polishing liquid for reducing the friction coefficient of the silicon wafer surface according to any one of claims 1 to 6, characterized in that: The alkaline compound is selected from at least one of potassium hydroxide, tetramethylammonium hydroxide, piperazine, diethylenetriamine, 4-aminopiperidine and ammonia water.

8. The fine polishing liquid for reducing the friction coefficient of the silicon wafer surface according to claim 7, characterized in that: The abrasive particles are nano-colloidal silicon dioxide.

9. The fine polishing liquid for reducing the friction coefficient of the silicon wafer surface according to claim 7, characterized in that: The primary particle size of the nano-colloidal silicon dioxide is 30-40 nm.

10. The fine polishing liquid for reducing the friction coefficient of the silicon wafer surface according to claim 7, characterized in that: The pH of the fine polishing solution is 10.0-11.0.

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