Polishing solution with low roughness and high removal amount as well as preparation method and application of polishing solution

Abstract

The invention relates to a low-roughness and high-removal-amount polishing solution and a preparation method and application thereof, in particular to the technical field of semiconductor polishing, and the polishing solution comprises the following components in percentage by mass: 1-30% of abrasive particles, 0.01-10% of a surfactant, 0.1-5% of a first auxiliary agent, 0.1-1% of a second auxiliary agent and the balance of water; the first auxiliary agent comprises one of polyether, guanidine salt, silane or monohydric alcohol; the second auxiliary agent comprises one of cellulose, a complexing agent, an organic silicon defoaming agent or dihydric alcohol; the pH value of the polishing solution is 9-11. According to the polishing solution provided by the invention, the formula of the polishing solution is adjusted, and the synergistic matching effect of the components in the polishing solution is adopted, so that the polishing solution has the advantages of high removal amount and low roughness of a removed surface, and efficient polishing of a silicon wafer is realized.

Description

Technical Field

[0001] The invention relates to the technical field of semiconductor polishing, and in particular to a polishing liquid with low roughness and high removal amount, and a preparation method and application thereof. Background Art

[0002] At present, chemical mechanical polishing technology has low requirements for equipment configuration, low sensitivity to the composition and structural heterogeneity of the material to be polished, will not produce adverse metallurgical conditions, and is highly practical. It is currently the only effective means to achieve ultra-precision flattening of large-size materials.

[0003] Among them, the polishing liquid that plays a decisive role is composed of chemical additives such as oxidants, pH adjusters, corrosion inhibitors, surfactants, complexing agents and chelating agents and abrasives in a certain proportion.

[0004] It is generally believed that grinding wafers with large-sized abrasives during the polishing process will result in excessive penetration depth and cause surface scratch defects, while small-sized abrasives make it difficult to achieve specific removal rate requirements.

[0005] Although CN104530987A discloses a silicon wafer fine polishing composition and a preparation method, which relates to the field of chemical mechanical polishing, the composition includes silica sol, hydroxyl nitrogen-containing alkaline compounds, hydroxyl carboxyl acidic compounds, alkaline compounds, polymer compounds, surfactants and deionized water; the particle size of the abrasive in the silica sol is 0.1-10nm.

[0006] However, this technical solution can only improve the precision of the polished silicon wafer, but cannot meet the removal rate requirements in practical applications. At the same time, the existing silicon wafer fine polishing liquid has problems such as poor stability, metal ion contamination and low removal rate of dielectric materials such as silicon dioxide. Summary of the invention

[0007] In view of the problems existing in the prior art, the purpose of the present invention is to provide a polishing liquid with low roughness and high removal amount, and its preparation method and use, so as to solve the defects of low removal amount and high roughness of the surface obtained after polishing the silicon wafer with the polishing liquid.

[0008] To achieve this object, the present invention adopts the following technical solutions:

[0009] In a first aspect, the present invention provides a low-roughness and high-removal polishing liquid, the polishing liquid comprising, by mass percentage:

[0010] Abrasive 1-30%, surfactant 0.01-10%, first additive 0.1-5%, second additive 0.1-1%, and the balance is water;

[0011] The first auxiliary agent includes one of polyether, guanidine salt, silane or monohydric alcohol;

[0012] The second auxiliary agent includes one of cellulose, complexing agent, silicone defoamer or diol;

[0013] The pH value of the polishing liquid is 9-11.

[0014] The polishing liquid provided by the present invention adjusts the formula of the polishing liquid and utilizes the synergistic effect of the components in the polishing liquid. When polishing a silicon wafer, the removal amount can reach more than 50nm / min under low pressure, low speed and high dilution ratio, and the surface roughness Ra of the obtained product is below 0.35nm; further, when polishing under a specific ratio, it can still have a good removal effect after being diluted 10-50 times, and the removal rate of polycrystalline silicon can reach more than 477nm / min, and the surface roughness Ra is below 0.53nm; further, when polishing with the polishing liquid under a specific ratio, as the polishing pressure increases, the removal amount decreases significantly to meet the requirements of special processes. further, under a specific ratio, the polishing liquid is guaranteed to maintain a basically unchanged removal amount when diluted to different times under a certain pressure, which is beneficial to improving the polishing effect. At the same time, when polishing polysilicon, the silicon removal amount is increased and the surface roughness Ra is significantly reduced.

[0015] As a preferred technical solution of the present invention, the particle size of the abrasive particles is 40-90 nm.

[0016] Preferably, the abrasive particles include spherical abrasive particles.

[0017] Preferably, the abrasive particles include silica abrasive particles.

[0018] Preferably, the surfactant comprises one of polysorbate, carboxymethyl cellulose, polyvinyl pyrrolidone or polyethylene glycol.

[0019] Preferably, the polyether comprises polyether F124 and / or polyether F127.

[0020] Preferably, the guanidine salt comprises one or a combination of at least two of guanidine hydrochloride, guanidine nitrate or guanidine carbonate.

[0021] Preferably, the silane comprises 3-aminopropylmethyldimethoxysilane and / or 3-aminopropyl(diethoxy)methylsilane.

[0022] Preferably, the monohydric alcohol comprises methanol and / or ethanol.

[0023] Preferably, the cellulose comprises carboxymethyl cellulose and / or hydroxyethyl cellulose.

[0024] Preferably, the complexing agent comprises hydroxyethylidene diphosphonic acid and / or EDTA.

[0025] Preferably, the diol comprises ethylene glycol.

[0026] As a preferred technical solution of the present invention, the polishing liquid comprises, by mass percentage:

[0027] 5-12% silicon dioxide abrasive, 0.1-10% polysorbate, 0.1-1% polyether F127, 0.1-1% hydroxyethyl cellulose, and the balance is water.

[0028] As a preferred technical solution of the present invention, the polishing liquid comprises, by mass percentage:

[0029] 15-20% silicon dioxide abrasive, 0.1-10% carboxymethyl cellulose, 0.1-3% guanidine nitrate, 0.1-1% hydroxyethylidene diphosphonic acid, and the balance is water.

[0030] As a preferred technical solution of the present invention, the polishing liquid comprises, by mass percentage:

[0031] 1-8% silicon dioxide abrasive, 2-10% polyvinyl pyrrolidone, 0.1-1% 3-aminopropyl (diethoxy) methyl silane, 0.1-1% organic silicon defoamer, and the balance is water.

[0032] As a preferred technical solution of the present invention, the polishing liquid comprises, by mass percentage:

[0033] 10-30% abrasive particles, 0.01-5% polyethylene glycol, 0.1-5% methanol, 0.1-1% ethylene glycol, and the balance is water.

[0034] As a preferred technical solution of the present invention, the polishing liquid also includes:

[0035] Fungicide 0.1-5%.

[0036] Preferably, the bactericide comprises BiT-20 and / or Kathon.

[0037] In a second aspect, the present invention provides a method for preparing the polishing liquid as described in the first aspect, the preparation method comprising:

[0038] The ingredients are prepared according to the formula of mass percentage, and then the polishing liquid is obtained by stirring and mixing.

[0039] In a third aspect, the present invention provides a use of the polishing liquid as described in the first aspect, wherein the use comprises: polishing a silicon wafer using the polishing liquid.

[0040] As a preferred technical solution of the present invention, the polishing pressure is 0.2-4psi;

[0041] Preferably, the polishing liquid used in the polishing is diluted 0-50 times.

[0042] Compared with the prior art solutions, the present invention has the following beneficial effects:

[0043] (1) The polishing liquid provided by the present invention achieves good removal of the silicon layer on the surface of the silicon wafer by adopting a specific polishing liquid composition and utilizing the combination of specific abrasive particles and surfactants such as polysorbate and the first auxiliary agent and the second auxiliary agent. Under low pressure (2-3.5 psi) and high dilution ratio (10-30 times), the removal amount can reach more than 50 nm / min, and the surface roughness Ra of the obtained product is below 0.35 nm.

[0044] (2) The polishing liquid provided by the present invention, through the reasonable design of the composition of the polishing liquid, utilizes the combination of abrasive particles and a specific surfactant carboxymethyl cellulose and a first auxiliary agent and a second auxiliary agent, and can still achieve efficient removal of polycrystalline silicon at a high dilution multiple (10-50 times), with a removal rate of more than 477nm / min, and the surface roughness Ra of the obtained product is less than 0.53nm.

[0045] (3) The silicon polishing liquid provided by the present invention is for When polishing polysilicon, the removal amount can be significantly reduced as the polishing pressure increases. When the polishing pressure increases from 0.3psi to 0.5psi, the removal amount can be reduced from 450-495nm / min to 390-425nm / min to meet The polishing requirement for polysilicon is that the removal amount is ≥421nm / min and the surface roughness of the resulting product is ≤0.54nm.

[0046] (4) The polishing liquid provided by the present invention has a good silicon removal effect when a specific ratio of polyethylene glycol, methanol and ethylene glycol is used. The removal amount can reach more than 410nm / min, and the surface roughness of the obtained product Ra≤0.51nm. At the same time, the polishing liquid has good stability. Furthermore, by selecting the raw materials of the polishing liquid, the potassium and sodium ions are controlled within 50ppb, and the other metal ions (calcium, magnesium, aluminum, etc.) are controlled within 20ppb, which can avoid metal ion contamination during the polishing process. DETAILED DESCRIPTION

[0047] To better illustrate the present invention and facilitate understanding of the technical solution of the present invention, typical but non-limiting embodiments of the present invention are as follows:

[0048] This embodiment provides a polishing liquid with low roughness and high removal rate, and the polishing liquid comprises, by mass percentage:

[0049] Abrasive 1-30%, surfactant 0.01-10%, first additive 0.1-5%, second additive 0.1-1%, and the balance is water;

[0050] The first auxiliary agent includes one of polyether, guanidine salt, silane or monohydric alcohol;

[0051] The second auxiliary agent includes one of cellulose, complexing agent, silicone defoamer or diol;

[0052] The pH value of the polishing liquid is 9-11.

[0053] In the present invention, the abrasive content in the low-roughness and high-removal polishing liquid is 1-30% by mass, for example, it can be 1%, 2%, 4%, 6%, 8%, 10%, 12%, 14%, 16%, 18%, 20%, 22%, 24%, 26%, 28% or 30%, etc., but is not limited to the listed values, and other values ​​not listed within this range also meet the requirements.

[0054] In the present invention, the surfactant content in the low-roughness and high-removal polishing liquid is 0.01-10% by mass, for example, it can be 0.01%, 0.02%, 0.04%, 0.06%, 0.08%, 0.1%, 0.2%, 0.4%, 0.6%, 0.8%, 1%, 2%, 4%, 6%, 8% or 10%, etc., but is not limited to the listed values, and other values ​​not listed within this range also meet the requirements.

[0055] In the present invention, the mass percentage of the first auxiliary agent in the low-roughness and high-removal polishing liquid is 0.1-5%, for example, it can be 0.1%, 0.2%, 0.3%, 0.4%, 0.5%, 0.6%, 0.7%, 0.8%, 0.9%, 1%, 2%, 3%, 4% or 5%, etc., but is not limited to the listed values, and other values ​​not listed within this range also meet the requirements.

[0056] In the present invention, the mass percentage of the second auxiliary agent in the low-roughness and high-removal polishing liquid is 0.1-1%, for example, it can be 0.1%, 0.2%, 0.3%, 0.4%, 0.5%, 0.6%, 0.7%, 0.8%, 0.9% or 1%, etc., but is not limited to the listed values, and other unlisted values ​​within this range also meet the requirements.

[0057] Wherein, the particle size of the abrasive particles is 40-90 nm.

[0058] In the present invention, the particle size range is defined as the aggregate of particles of uniform particle size within the range or the aggregate of all particles within a certain particle size range.

[0059] Wherein, the abrasive particles include spherical abrasive particles.

[0060] Wherein, the abrasive particles include silicon dioxide abrasive particles.

[0061] Wherein, the surfactant includes one of polysorbate, carboxymethyl cellulose, polyvinyl pyrrolidone or polyethylene glycol.

[0062] Wherein, the polyether includes polyether F124 and / or polyether F127.

[0063] Wherein, the guanidine salt includes one or a combination of at least two of guanidine hydrochloride, guanidine nitrate or guanidine carbonate.

[0064] Wherein, the silane includes 3-aminopropylmethyldimethoxysilane and / or 3-aminopropyl(diethoxy)methylsilane.

[0065] Wherein, the monohydric alcohol includes methanol and / or ethanol.

[0066] Wherein, the cellulose includes carboxymethyl cellulose and / or hydroxyethyl cellulose.

[0067] Wherein, the complexing agent includes hydroxyethylidene diphosphonic acid and / or EDTA.

[0068] Wherein, the diol includes ethylene glycol.

[0069] In the present invention, when the components in the polishing liquid are matched in a specific ratio, the polishing liquid can also have specific effects under different working conditions. For example, when the surfactant is polysorbate, and the additives are polyether and cellulose, the removal amount can reach more than 50nm / min and the roughness is less than 0.35nm under low pressure, low speed and high dilution ratio during polishing. At this time, the ratio of the polishing liquid is as follows:

[0070] The composition comprises, by mass percentage, 5-12% abrasive particles, 0.1-10% polysorbate, 0.1-1% polyether, 0.1-1% cellulose, and the balance is water.

[0071] At this time, the particle size of the abrasive in the polishing liquid is 40-60nm, the mass percentage of the abrasive in the polishing liquid is 5-12%, for example, it can be 5%, 6%, 7%, 8%, 9%, 10%, 11% or 12%, the mass percentage of polysorbate is 0.1-10%, for example, it can be 0.1%, 0.2%, 0.4%, 0.6%, 0.8%, 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9% or 10%, and the mass percentage of polyether is 0.1-1%, for example, it can be 0.1%, 0.2%, 0.3%, 0.4%, 0.5%, 0.6%, 0.7%, 0.8%, 0.9% or 1%, etc., the cellulose content is 0.1-1% by mass, for example, it can be 0.1%, 0.2%, 0.3%, 0.4%, 0.5%, 0.6%, 0.7%, 0.8%, 0.9% or 1%, etc., but is not limited to the listed values, and other unlisted values ​​within this range also meet the requirements; under the preferred embodiment, the polishing liquid includes, by mass percentage: 5-12% silica abrasive, 0.1-10% polysorbate, 0.1-1% polyether F127, 0.1-1%, 0.1-1% hydroxyethyl cellulose, 0.1-5% pH regulator, and the balance is water.

[0072] When the surfactant is carboxymethyl cellulose and the additives are guanidine salt and complexing agent, the polishing liquid can still have a good removal effect after being diluted 10-50 times during polishing, and the removal rate of polysilicon can reach more than 477nm / min. At this time, the proportion of the polishing liquid is as follows:

[0073] The composition comprises, by mass percentage, 15-20% abrasive particles, 0.1-10% carboxymethyl cellulose, 0.1-5% pH value regulator, 0.1-3% guanidine salt, 0.1-1% complexing agent, and the balance is water.

[0074] At this time, the particle size of the abrasive in the polishing liquid is 55-75nm, the mass percentage of the abrasive is 15-20%, for example, it can be 15%, 16%, 17%, 18%, 19% or 20%, etc., the mass percentage of carboxymethyl cellulose is 0.1-10%, for example, it can be 0.1%, 0.2%, 0.4%, 0.6%, 0.8%, 1%, 2%, 4%, 6%, 8% or 10%, etc., and the mass percentage of guanidine salt is 0.1-3%, for example, it can be 0.1%, 0.2%, 0.4%, 0.6%, 0.8%, 1%, 2%, 4%, 6%, 8% or 10%. 1%, 1.5%, 2%, 2.5% or 3%, etc., the complexing agent is 0.1-1% by mass, for example, it can be 0.1%, 0.2%, 0.4%, 0.6%, 0.8% or 1%, etc., but is not limited to the listed values, and other unlisted values ​​within this range also meet the requirements; under the preferred embodiment, the polishing liquid includes, by mass percentage: 15-20% silica abrasive, 0.1-10% carboxymethyl cellulose, 0.1-3% guanidine nitrate, 0.1-1% hydroxyethylidene diphosphonic acid, 0.1-5% pH adjuster, and the balance is water.

[0075] When the surfactant is polyvinyl pyrrolidone and the additives are silane and silicone defoamer, the removal amount can be significantly reduced as the polishing pressure increases. At this time, the polishing liquid ratio is as follows:

[0076] Abrasive 1-8%, polyvinyl pyrrolidone 2-10%, silane 0.1-1%, organosilicon defoamer 0.1-1%, and the balance is water.

[0077] At this time, the particle size of the abrasive in the polishing liquid is 70-90nm, the mass percentage of the abrasive is 1-8%, for example, it can be 1%, 2%, 3%, 4%, 5%, 6%, 7% or 8%, etc., the mass percentage of polyvinyl pyrrolidone is 2-10%, for example, it can be 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9% or 10%, etc., and the mass percentage of silane is 0.1-1%, for example, it can be 0.1%, 0.2%, 0.4%, 0.6%, 0.8% or 1%. etc., the mass percentage of the silicone defoamer is 0.1-1%, such as 0.1%, 0.2%, 0.4%, 0.6%, 0.8% or 1%, etc., but is not limited to the listed values, and other unlisted values ​​within the range also meet the requirements; under the preferred embodiment, the polysilicon polishing liquid includes, by mass percentage: 1-8% silicon dioxide abrasive, 2-10% polyvinyl pyrrolidone, 0.1-1% 3-aminopropyl (diethoxy) methyl silane, 0.1-1% silicone defoamer, and the balance is water.

[0078] When the surfactant is polyethylene glycol and the additives are monohydric alcohol and dihydric alcohol, the polishing liquid can maintain a basically unchanged removal amount when diluted to different times under a certain pressure, which is beneficial to improving the polishing effect. At this time, the proportion of the polishing liquid is as follows:

[0079] The composition comprises, by mass percentage, 10-30% of abrasive grains, 0.01-5% of polyethylene glycol, 0.1-5% of monohydric alcohol, 0.1-1% of dihydric alcohol, and the balance of water.

[0080] At this time, the particle size of the abrasive particles in the polishing liquid is 50-70nm, the mass percentage of the abrasive is 10-30%, for example, it can be 10%, 12%, 14%, 16%, 18%, 20%, 22%, 24%, 26%, 28% or 30%, etc., the mass percentage of polyethylene glycol is 0.05-5%, for example, it can be 0.05%, 0.06%, 0.07%, 0.08%, 0.09%, 0.1%, 0.2%, 0.4%, 0.6%, 0.8%, 1%, 2%, 3%, 4% or 5%, etc., the mass percentage of the monohydric alcohol is 0.1-5%, for example, it can be 0.1%, 0.2%, 0.4%, 0.6%, 0.8%, 1%, 2%, 3%, 4% or 5%, etc., the glycol is 0.1-1% by mass percentage, for example, it can be 0.1%, 0.2%, 0.4%, 0.6%, 0.8% or 1%, etc., but is not limited to the listed values, and other unlisted values ​​within the range also meet the requirements; under the preferred embodiment, the polishing liquid includes, by mass percentage: 10-30% abrasive, 0.01-5% polyethylene glycol, 0.1-5% methanol, 0.1-1% ethylene glycol, and the balance is water.

[0081] In the present invention, the polishing liquid also contains a bactericide, the mass percentage content is 0.1-5%, for example, it can be 0.1%, 0.2%, 0.4%, 0.6%, 0.8%, 1%, 2%, 3%, 4% or 5%, etc., but is not limited to the listed values, and other unlisted values ​​within this range also meet the requirements.

[0082] Wherein, the bactericide includes BiT-20 and / or Kathon.

[0083] In the present invention, the polysorbates used include polysorbate-20, polysorbate-40, polysorbate-60 and the like.

[0084] In the present invention, the molecular weight of the polyvinyl pyrrolidone used is 45000-58000.

[0085] In the present invention, the polyethylene glycol used includes PEG1000, PEG1500 or PEG2000 and the like.

[0086] Specifically, the bactericide includes BiT-20 and / or Kathon.

[0087] In the present invention, the reagents used in adjusting the pH value of the polishing liquid include ammonia water, ethanolamine, methanesulfonic acid, maleic acid or alginic acid, etc. Among them, when the surfactant is polyethylene glycol and the auxiliary agent is monohydric alcohol and dihydric alcohol, the pH value is beneficial to the realization of the polishing effect when the pH value is adjusted by introducing an organic acid, preferably methanesulfonic acid, at which time the amount of the organic acid added is 0.1-5%, and the pH value is adjusted to a limited range of 9-10 with an alkali.

[0088] In the present invention, the mass concentration of the ammonia water used is 0.3-1%.

[0089] Furthermore, the present invention provides a method for preparing the aforementioned polishing liquid, the preparation method comprising:

[0090] The ingredients are prepared according to the formula of mass percentage, and then the polishing liquid is obtained by stirring and mixing.

[0091] Specifically, the preparation method comprises: first stirring water, a surfactant, a first auxiliary agent and a second auxiliary agent, then adding abrasive particles for second stirring, and adding a bactericide after adjusting the pH value for third stirring to obtain a polishing liquid.

[0092] In the present invention, the raw materials used in the process of preparing the polishing liquid can be ultra-high purity raw materials to avoid the contamination of the silicon wafer by metal elements in the polishing liquid during the polishing process.

[0093] Wherein, the stirring speed of the first stirring is 150-250r / min, for example, it can be 150r / min, 160r / min, 170r / min, 180r / min, 190r / min, 200r / min, 210r / min, 220r / min, 230r / min, 240r / min or 250r / min, but is not limited to the listed values, and other unlisted values ​​within the range also meet the requirements.

[0094] Wherein, the first stirring time is 30-40 min, for example, it can be 30 min, 31 min, 32 min, 33 min, 34 min, 35 min, 36 min, 37 min, 38 min, 39 min or 40 min, but is not limited to the listed values, and other unlisted values ​​within the range also meet the requirements.

[0095] Wherein, the stirring speed of the second stirring is 150-250r / min, for example, it can be 150r / min, 160r / min, 170r / min, 180r / min, 190r / min, 200r / min, 210r / min, 220r / min, 230r / min, 240r / min or 250r / min, but is not limited to the listed values, and other unlisted values ​​within the range also meet the requirements.

[0096] Wherein, the second stirring time is 60-80 min, for example, it can be 60 min, 62 min, 64 min, 66 min, 68 min, 70 min, 72 min, 74 min, 76 min, 78 min or 80 min, but is not limited to the listed values, and other unlisted values ​​within the range also meet the requirements.

[0097] Among them, the stirring speed of the third stirring is 150-250r / min, for example, it can be 150r / min, 160r / min, 170r / min, 180r / min, 190r / min, 200r / min, 210r / min, 220r / min, 230r / min, 240r / min or 250r / min, but is not limited to the listed values, and other unlisted values ​​within the range also meet the requirements.

[0098] Wherein, the third stirring time is 60-90min, for example, it can be 60min, 62min, 64min, 66min, 68min, 70min, 72min, 74min, 76min, 78min, 80min, 82min, 84min, 86min, 88min or 90min, but is not limited to the listed values, and other unlisted values ​​within the range also meet the requirements.

[0099] Furthermore, the present invention provides a use of the aforementioned polishing liquid, which includes: polishing a silicon wafer using the polishing liquid.

[0100] Specifically, the polishing pressure is 0.2-4psi, for example, it can be 0.2psi, 0.4psi, 0.6psi, 0.8psi, 1psi, 1.5psi, 2psi, 2.5psi, 3psi, 3.5psi or 4psi, but is not limited to the listed values, and other unlisted values ​​within the range also meet the requirements.

[0101] Specifically, the polishing liquid used in the polishing is diluted 0-50 times, for example, it can be 0, 5, 10, 15, 20, 25, 30, 35, 40, 45 or 50 times, but is not limited to the listed values, and other unlisted values ​​within this range also meet the requirements.

[0102] Further, in order to illustrate the polishing effect that can be achieved by the polishing liquid with low roughness and high removal amount provided by the present invention, the following actual examples are used for illustration, as follows:

[0103] I. When the surfactant is polysorbate and the additive is polyether and cellulose

[0104] Example 1

[0105] This embodiment provides a polishing liquid for low-roughness and high-removal silicon wafers, which comprises, by mass percentage:

[0106] Abrasive 10%, surfactant 5%, bactericide 3%, polyether F124 0.4%, carboxymethyl cellulose 0.6%, and the balance is water;

[0107] The abrasive particles have a particle size of 40-60 nm and are spherical silica abrasive particles;

[0108] The surfactant is polysorbate-20;

[0109] The bactericide is BiT-20.

[0110] The preparation process is as follows:

[0111] The water, surfactant, polyether and carboxymethyl cellulose are first stirred, and then abrasive particles are added for second stirring. After adjusting the pH value (the pH value adjuster used is ethanolamine), a bactericide is added for third stirring to obtain a polishing liquid with a pH value of 10;

[0112] The stirring speed of the first stirring is 200 r / min; the time of the first stirring is 35 min; the stirring speed of the second stirring is 200 r / min; the time of the second stirring is 70 min; the stirring speed of the third stirring is 200 r / min; the time of the third stirring is 70 min.

[0113] The polishing process is as follows:

[0114] Polishing a silicon wafer using the polishing liquid;

[0115] The polishing pressure is 2.5 psi; the polishing liquid used in the polishing is diluted 20 times.

[0116] Example 2

[0117] This embodiment provides a polishing liquid with low roughness and high removal rate, which comprises, by mass percentage:

[0118] Abrasive 12%, surfactant 1%, bactericide 2%, polyether F127 0.6%, hydroxyethyl cellulose 0.4%, the balance is water;

[0119] The abrasive particles have a particle size of 40-60 nm and are spherical silica abrasive particles;

[0120] The surfactant is polysorbate-20;

[0121] The bactericide is kasone.

[0122] The preparation process is as follows:

[0123] The water, surfactant, polyether and hydroxyethyl cellulose are first stirred, then the abrasive is added for second stirring, the pH value is adjusted (the pH value adjuster used is ammonia water, the mass concentration is 0.5%), and then the bactericide is added for third stirring to obtain a polishing liquid with a pH value of 10.2;

[0124] The stirring speed of the first stirring is 220 r / min; the time of the first stirring is 32 min; the stirring speed of the second stirring is 220 r / min; the time of the second stirring is 65 min; the stirring speed of the third stirring is 180 r / min; and the time of the third stirring is 80 min.

[0125] The polishing process is as follows:

[0126] Polishing a silicon wafer using the polishing liquid;

[0127] The polishing pressure is 3 psi; the polishing liquid used in the polishing is diluted 20 times.

[0128] Example 3

[0129] This embodiment provides a polishing liquid for low-roughness and high-removal silicon wafers, which comprises, by mass percentage:

[0130] Abrasive 5%, surfactant 10%, fungicide 0.1%, polyether F124 0.1%, carboxymethyl cellulose 1%, the balance is water;

[0131] The abrasive particles have a particle size of 40-55 nm and are spherical silica abrasive particles;

[0132] The surfactant is polysorbate-40;

[0133] The bactericide is kasone.

[0134] The preparation process is as follows:

[0135] The water, surfactant, polyether and carboxymethyl cellulose are first stirred, and then the abrasive is added for second stirring, and the pH value is adjusted (the pH value adjuster used is ammonia water with a mass concentration of 1%) and then the bactericide is added for third stirring to obtain a polishing liquid with a pH value of 10.5;

[0136] The stirring speed of the first stirring is 150 r / min; the time of the first stirring is 40 min; the stirring speed of the second stirring is 150 r / min; the time of the second stirring is 80 min; the stirring speed of the third stirring is 150 r / min; and the time of the third stirring is 90 min.

[0137] The polishing process is as follows:

[0138] Polishing a silicon wafer using the polishing liquid;

[0139] The polishing pressure is 3.5 psi; the polishing liquid used in the polishing is diluted 30 times.

[0140] Example 4

[0141] This embodiment provides a polishing liquid for low-roughness and high-removal silicon wafers, which comprises, by mass percentage:

[0142] Abrasive 12%, surfactant 0.1%, fungicide 5%, polyether F127 1%, hydroxyethyl cellulose 0.1%, the balance is water;

[0143] The abrasive particles have a particle size of 50-60 nm and are spherical silica abrasive particles;

[0144] The surfactant is polysorbate-60;

[0145] The bactericide is BiT-20 and Kasong in a mass ratio of 1:1.

[0146] The preparation process is as follows:

[0147] The water, surfactant, polyether and hydroxyethyl cellulose are first stirred, and then the abrasive is added for second stirring, the pH value is adjusted (the pH value adjuster used is ammonia water and ethanolamine with a mass concentration of 0.3% in a mass ratio of 1:1), and then the bactericide is added for fourth stirring to obtain a polishing liquid with a pH value of 9.5;

[0148] The stirring speed of the first stirring is 250 r / min; the time of the first stirring is 30 min; the stirring speed of the second stirring is 250 r / min; the time of the second stirring is 60 min; the stirring speed of the third stirring is 250 r / min; the time of the third stirring is 60 min.

[0149] The polishing process is as follows:

[0150] Polishing a silicon wafer using the polishing liquid;

[0151] The polishing pressure is 2 psi; the polishing liquid used in the polishing is diluted 10 times.

[0152] Example 5

[0153] The only difference from Example 1 is that polyether F124 is replaced by an equal amount of polyether F127.

[0154] Example 6

[0155] The only difference from Example 1 is that carboxymethyl cellulose is replaced by an equal amount of hydroxyethyl cellulose.

[0156] Example 7

[0157] The only difference from Example 1 is that the mass percentage of the surfactant is 0.05%.

[0158] Example 8

[0159] The only difference from Example 1 is that the mass percentage of the surfactant is 15%.

[0160] Example 9

[0161] The only difference from Example 1 is that the mass percentage of abrasive grains is 3%.

[0162] Example 10

[0163] The only difference from Example 1 is that the mass percentage of abrasive grains is 20%.

[0164] Embodiment 11

[0165] The only difference from Example 1 is that the surfactant is replaced by an equal amount of sorbitan monolaurate.

[0166] Example 12

[0167] The only difference from Example 1 is that polyether F124 is replaced by an equal amount of polyether L64.

[0168] Example 13

[0169] The only difference from Example 1 is that carboxymethyl cellulose is replaced by methyl cellulose.

[0170] Embodiment 14

[0171] The only difference from Example 1 is that the particle size of the abrasive particles is 10-20 nm.

[0172] Embodiment 15

[0173] The only difference from Example 1 is that the particle size of the abrasive particles is 80-90 nm.

[0174] The polishing results of the above embodiment are shown in Table 1 below. The polishing pad used in the polishing process is H800, the rotation speed of the polishing disc is 93 r / min, the rotation speed of the polishing head is 87 r / min, the flow rate of the polishing liquid is 200 mL / min, and the polishing time is 1 min.

[0175] Table 1

[0176] Silicon removal amount / nm / min Surface roughness Ra / nm Example 1 69 0.35 Example 2 82 0.21 Example 3 72 0.24 Example 4 74 0.25 Example 5 79 0.12 Example 6 77 0.13 Example 7 35 0.91 Example 8 36 1.52 Example 9 44 1.31 Example 10 35 1.23 Embodiment 11 49 1.22 Example 12 45 2.51 Example 13 32 3.23 Embodiment 14 48 1.51 Embodiment 15 70 2.32

[0177] As can be seen from Table 1, in the solution provided by the present invention, by adopting a specific polishing liquid composition and utilizing specific abrasives and surfactants such as polysorbate, good removal of the silicon layer on the surface of the silicon wafer is achieved. Under low pressure (2-3.5psi) and high dilution ratio (10-30 times), the removal amount can reach more than 50nm / min, and the roughness is below 0.35nm.

[0178] II. When the surfactant is carboxymethyl cellulose and the auxiliary agent is guanidine salt and complexing agent, the following practical examples are used for illustration, as follows:

[0179] Example 16

[0180] This embodiment provides a polishing liquid with a high dilution ratio, and the polishing liquid comprises, by weight percentage:

[0181] Abrasive 15%, surfactant 5%, bactericide 2%, guanidine hydrochloride 1%, EDTA 0.4%, the balance is water;

[0182] The abrasive particles are spherical silicon dioxide abrasive particles with a particle size of 60-70 nm;

[0183] The surfactant is carboxymethyl cellulose;

[0184] The bactericide is kasone.

[0185] The preparation process is as follows:

[0186] The water, the surfactant, the guanidine hydrochloride and the EDTA are mixed and stirred for the first time, the abrasive is added and stirred for the second time, the pH value is adjusted (the pH value adjuster used is tetramethylammonium hydroxide) and then the bactericide is added and stirred for the third time to obtain a polishing liquid with a pH value of 11;

[0187] The rotation speed of the first stirring is 220 r / min; the time of the first stirring is 40 min; the rotation speed of the second stirring is 220 r / min; the time of the second stirring is 75 min; the rotation speed of the third stirring is 220 r / min; and the time of the third stirring is 80 min.

[0188] The polishing process for polysilicon is as follows:

[0189] The polishing liquid is used to polish polysilicon, the polishing pressure is 2 psi, and the polishing liquid is diluted 20 times during polishing.

[0190] Embodiment 17

[0191] This embodiment provides a polishing liquid with a high dilution ratio, and the polishing liquid comprises, by weight percentage:

[0192] Abrasive 18%, surfactant 1%, bactericide 3%, guanidine nitrate 2%, hydroxyethylidene diphosphonic acid 0.6%, and the balance is water;

[0193] The abrasive particles are spherical silicon dioxide abrasive particles with a particle size of 55-65 nm;

[0194] The surfactant is carboxymethyl cellulose;

[0195] The bactericide is BiT-20.

[0196] The preparation process is as follows:

[0197] The water, surfactant, guanidine nitrate and hydroxyethylidene diphosphonic acid are mixed and stirred for the first time, the abrasive is added and stirred for the second time, the pH value is adjusted (the pH value adjuster used is ammonia water with a mass concentration of 2%), and then the bactericide is added and stirred for the third time to obtain a polishing liquid with a pH value of 11.2;

[0198] The rotation speed of the first stirring is 240 r / min; the time of the first stirring is 35 min; the rotation speed of the second stirring is 240 r / min; the time of the second stirring is 70 min; the rotation speed of the third stirring is 240 r / min; and the time of the third stirring is 70 min.

[0199] The polishing process for polysilicon is as follows:

[0200] The polishing liquid is used to polish polysilicon, the polishing pressure is 3 psi, and the polishing liquid is diluted 40 times during polishing.

[0201] Embodiment 18

[0202] This embodiment provides a polishing liquid with a high dilution ratio, and the polishing liquid comprises, by weight percentage:

[0203] Abrasive 15%, surfactant 0.1%, bactericide 5%, guanidine carbonate 0.1%, hydroxyethylidene diphosphonic acid 1%, and the balance is water;

[0204] The abrasive particles are spherical silicon dioxide abrasive particles with a particle size of 55-75 nm;

[0205] The surfactant is carboxymethyl cellulose;

[0206] The bactericide is BiT-20.

[0207] The preparation process is as follows:

[0208] The water, surfactant, guanidine carbonate and hydroxyethylidene diphosphonic acid are mixed and stirred for the first time, abrasive grains are added and stirred for the second time, the pH value is adjusted (the pH value adjuster used is tetramethylammonium hydroxide with a mass ratio of 1:1 and ammonia water with a mass concentration of more than 3%), and then a bactericide is added and stirred for the third time to obtain a polishing liquid with a pH value of 10.5;

[0209] The rotation speed of the first stirring is 250 r / min; the time of the first stirring is 30 min; the rotation speed of the second stirring is 250 r / min; the time of the second stirring is 60 min; the rotation speed of the third stirring is 250 r / min; the time of the third stirring is 60 min.

[0210] The polishing process for polysilicon is as follows:

[0211] The polishing liquid is used to polish polysilicon, the polishing pressure is 1.5 psi, and the polishing liquid is diluted 10 times during polishing.

[0212] Embodiment 19

[0213] This embodiment provides a polishing liquid with a high dilution ratio, and the polishing liquid comprises, by weight percentage:

[0214] Abrasive 20%, surfactant 10%, bactericide 0.1%, guanidine nitrate 3%, EDTA 0.1%, the balance is water;

[0215] The abrasive particles are spherical silicon dioxide abrasive particles with a particle size of 55-75 nm;

[0216] The surfactant is carboxymethyl cellulose;

[0217] The bactericide is BiT-20 and Kasong in a mass ratio of 1:1.

[0218] The preparation process is as follows:

[0219] The water, surfactant, guanidine nitrate and EDTA are mixed and stirred for the first time, the abrasive is added and stirred for the second time, the pH value is adjusted (the pH value adjuster used is tetramethylammonium hydroxide) and then the bactericide is added and stirred for the third time to obtain a polishing liquid with a pH value of 11.5;

[0220] The rotation speed of the first stirring is 200 r / min; the time of the first stirring is 45 min; the rotation speed of the second stirring is 200 r / min; the time of the second stirring is 80 min; the rotation speed of the third stirring is 200 r / min; and the time of the third stirring is 90 min.

[0221] The polishing process for polysilicon is as follows:

[0222] The polishing liquid is used to polish polysilicon, the polishing pressure is 4 psi, and the polishing liquid is diluted 50 times during polishing.

[0223] Embodiment 20

[0224] The only difference from Example 16 is that guanidine hydrochloride is replaced by an equal amount of guanidine nitrate.

[0225] Embodiment 21

[0226] The only difference from Example 16 is that EDTA is replaced by an equal amount of hydroxyethylidene diphosphonic acid.

[0227] Embodiment 22

[0228] The only difference from Example 17 is that the polishing liquid is diluted 35 times during polishing.

[0229] Embodiment 23

[0230] The only difference from Example 17 is that the polishing liquid is diluted 40 times during polishing.

[0231] Embodiment 24

[0232] The only difference from Example 16 is that the mass percentage of abrasive particles in the polishing liquid is 5%.

[0233] Embodiment 25

[0234] The only difference from Example 16 is that the mass percentage of abrasive particles in the polishing liquid is 25%.

[0235] Embodiment 26

[0236] The only difference from Example 16 is that the particle size of the abrasive particles in the polishing liquid is 30-40 nm.

[0237] Embodiment 27

[0238] The only difference from Example 16 is that the mass percentage of the surfactant in the polishing liquid is 0.05%.

[0239] Embodiment 28

[0240] The only difference from Example 16 is that the mass percentage of the surfactant in the polishing liquid is 15%.

[0241] Embodiment 29

[0242] The only difference from Example 16 is that the surfactant is replaced with an equal amount of polysorbate-20.

[0243] Embodiment 30

[0244] The only difference from Example 16 is that the surfactant is replaced by an equal amount of methylcellulose.

[0245] Embodiment 31

[0246] The only difference from Example 16 is that the abrasive is replaced with aluminum oxide abrasive with the same parameters.

[0247] The polishing results of the above embodiments and comparative examples are shown in Table 2. The polishing pad used in the polishing process is IC1010, the rotation speed of the polishing disc is 93 r / min, the rotation speed of the polishing head is 87 r / min, the flow rate of the polishing liquid is 200 mL / min, and the polishing time is 1 min.

[0248] Table 2

[0249] Removal amount / nm / min Roughness Ra / nm Example 16 480 0.42 Embodiment 17 525 0.15 Embodiment 18 490 0.51 Embodiment 19 493 0.53 Embodiment 20 510 0.15 Embodiment 21 508 0.15 Embodiment 22 482 0.11 Embodiment 23 477 0.22 Embodiment 24 320 2.23 Embodiment 25 331 3.25 Embodiment 26 254 3.67 Embodiment 27 312 2.78 Embodiment 28 324 3.29 Embodiment 29 276 2.35 Embodiment 30 312 1.98 Embodiment 31 285 3.13

[0250] As can be seen from Table 2, the polishing liquid provided by the present invention, through the reasonable design of the composition of the polishing liquid, utilizes the combination of abrasive particles and a specific surfactant carboxymethyl cellulose, and can still achieve efficient removal of polycrystalline silicon at a high dilution multiple (10-50 times), and the removal rate can reach more than 477nm / min, and the surface roughness Ra of the obtained product is less than 0.53nm.

[0251] III. When the surfactant is polyvinyl pyrrolidone and the auxiliary agent is silane and silicone defoamer, the following practical examples are used for illustration, as follows:

[0252] Embodiment 32

[0253] This embodiment provides a polysilicon polishing liquid in which the pressure is inversely proportional to the removal amount, which comprises, by mass percentage: 7% abrasive, 8% surfactant, 1.5% bactericide, 0.4% 3-aminopropylmethyldimethoxysilane, 0.6% organic silicon defoamer (CAS No.: NONE6712), and the balance is water;

[0254] The abrasive particles are spherical silicon dioxide abrasive particles with a particle size of 70-75 nm;

[0255] The surfactant is polyvinyl pyrrolidone (molecular weight is 50000);

[0256] The bactericide is kasone.

[0257] The preparation process is as follows:

[0258] The water, the surfactant, the 3-aminopropylmethyldimethoxysilane and the organosilicon defoamer are mixed and stirred for the first time, the abrasive is added and stirred for the second time, the pH value is adjusted (the pH value adjuster used is sodium hydroxide) and then the bactericide is added and stirred for the third time to obtain a polysilicon polishing liquid with a pH value of 11;

[0259] The first stirring speed is 160r / min; the first stirring time is 50min; the second stirring speed is 160r / min; the second stirring time is 100min; the third stirring speed is 160r / min; the fourth stirring time is 80min;

[0260] The polishing process is as follows: the polysilicon polishing liquid is used to polish the polysilicon, and the pressure during polishing is 0.3 psi.

[0261] Embodiment 33

[0262] This embodiment provides a polysilicon polishing liquid in which the pressure is inversely proportional to the removal amount, which comprises, by mass percentage: 4% abrasive, 6% surfactant, 1% bactericide, 0.6% 3-aminopropyl (diethoxy) methyl silane, 0.4% organosilicon defoamer (CAS No.: NONE6712), and the balance is water;

[0263] The abrasive particles are spherical silicon dioxide abrasive particles with a particle size of 80-90 nm;

[0264] The surfactant is polyvinyl pyrrolidone (molecular weight 45000);

[0265] The bactericide is BiT-20.

[0266] The preparation process is as follows:

[0267] The water, the surfactant, the 3-aminopropyl (diethoxy) methyl silane and the organosilicon defoamer are mixed and stirred for the first time, the abrasive is added and stirred for the second time, and the bactericide is added and stirred for the third time after the pH value is adjusted (the pH value adjuster used is potassium hydroxide) to obtain a polysilicon polishing liquid with a pH value of 10.8;

[0268] The first stirring speed is 180r / min; the first stirring time is 40min; the second stirring speed is 180r / min; the second stirring time is 80min; the third stirring speed is 180r / min; the third stirring time is 80min;

[0269] The polishing process is as follows: the polysilicon polishing liquid is used to polish the polysilicon, and the pressure during polishing is 0.4 psi.

[0270] Embodiment 34

[0271] This embodiment provides a polysilicon polishing liquid in which the pressure is inversely proportional to the removal amount, which comprises, by mass percentage: 8% abrasive, 10% surfactant, 0.1% bactericide, 0.1% 3-aminopropylmethyldimethoxysilane, 1% organic silicon defoamer (CAS No.: NONE6712), and the balance is water;

[0272] The abrasive particles are spherical silicon dioxide abrasive particles with a particle size of 75-85 nm;

[0273] The surfactant is polyvinyl pyrrolidone (molecular weight is 50000);

[0274] The bactericide is BiT-20.

[0275] The preparation process is as follows:

[0276] The water, the surfactant, the 3-aminopropylmethyldimethoxysilane and the organosilicon defoamer are mixed and stirred for the first time, the abrasive is added and stirred for the second time, the pH value is adjusted (the pH value adjuster used is potassium hydroxide), and then the bactericide is added and stirred for the third time to obtain a polysilicon polishing liquid with a pH value of 11.5;

[0277] The first stirring speed is 150r / min; the first stirring time is 60min; the second stirring speed is 150r / min; the second stirring time is 120min; the third stirring speed is 150r / min; the third stirring time is 90min;

[0278] The polishing process is as follows: the polysilicon polishing liquid is used to polish the polysilicon, and the pressure during polishing is 0.2 psi.

[0279] Embodiment 35

[0280] This embodiment provides a polysilicon polishing liquid in which the pressure is inversely proportional to the removal amount, which comprises, by mass percentage: 1% abrasive, 2% surfactant, 2% bactericide, 1% 3-aminopropyl (diethoxy) methyl silane, 0.1% organic silicon defoamer (CAS No.: NONE6712), and the balance is water;

[0281] The abrasive particles are spherical silicon dioxide abrasive particles with a particle size of 70-90 nm;

[0282] The surfactant is polyvinyl pyrrolidone (molecular weight is 58000);

[0283] The bactericide is kasone.

[0284] The preparation process is as follows:

[0285] Water, surfactant, 3-aminopropyl (diethoxy) methyl silane and silicone defoamer are mixed and stirred for the first time, abrasive grains are added and stirred for the second time, pH value is adjusted (the pH value adjuster used is ammonia water with a mass concentration of 0.5%), and then a fungicide is added and stirred for the third time to obtain a polysilicon polishing liquid with a pH value of 10.5;

[0286] The first stirring speed is 200 r / min; the first stirring time is 30 min; the second stirring speed is 200 r / min; the second stirring time is 60 min; the third stirring speed is 200 r / min; the third stirring time is 60 min;

[0287] The polishing process is as follows: the polysilicon polishing liquid is used to polish the polysilicon, and the pressure during polishing is 0.5 psi.

[0288] Embodiment 36

[0289] The only difference from Example 32 is that 3-aminopropylmethyldimethoxysilane is replaced by an equal amount of 3-aminopropyl(diethoxy)methylsilane.

[0290] Embodiment 37

[0291] The only difference from Example 33 was that the pressure during polishing was 0.4 psi.

[0292] Embodiment 38

[0293] The only difference from Example 33 was that the pressure during polishing was 0.5 psi.

[0294] Embodiment 39

[0295] The only difference from Example 33 is that the surfactants used are polyvinyl pyrrolidone (molecular weight 50,000) and hydroxyethyl cellulose in a mass ratio of 1:1.

[0296] Embodiment 40

[0297] The only difference from Example 32 is that the particle size of the abrasive is 20-50 nm.

[0298] Embodiment 41

[0299] The only difference from Example 32 is that the particle size of the abrasive is 100-120 nm.

[0300] Embodiment 42

[0301] The only difference from Example 32 is that the mass percentage of abrasive particles in the polishing liquid is 15%.

[0302] Embodiment 43

[0303] The only difference from Example 32 is that the mass percentage of the surfactant in the polishing liquid is 1%.

[0304] Embodiment 44

[0305] The only difference from Example 32 is that the mass percentage of the surfactant in the polishing liquid is 0.5%.

[0306] The polishing effects of the above embodiments and comparative examples are described in detail in Table 3. The polishing pad used in the polishing process is Suba400, the rotation speed of the polishing disc is 93r / min, the rotation speed of the polishing head is 87r / min, the flow rate of the polishing liquid is 200mL / min, and the polishing time is 1min.

[0307] Table 3

[0308]

[0309]

[0310] As shown in Table 3, the polysilicon polishing liquid provided by the present invention achieves the following objectives by controlling the specific composition and ratio of the polishing liquid: When polishing polysilicon, the advantage of significantly reducing the amount of removal can be achieved as the polishing pressure increases, while achieving a good polishing effect.

[0311] IV. When the surfactant is polyethylene glycol and the auxiliary agent is monohydric alcohol and dihydric alcohol, the following practical examples are used for illustration, as follows:

[0312] Embodiment 45

[0313] This embodiment provides a polishing liquid with a constant removal amount under different dilution multiples, which includes, by mass percentage:

[0314] Abrasive 20%, polyethylene glycol PEG-1000 2.5%, fungicide 0.5%, maleic acid 2%, ethanol 3%, ethylene glycol 0.3%, the balance is water, the pH value of the polishing liquid is 9.7;

[0315] The abrasive particles are spherical silica abrasive particles with a particle size of 50-60 nm;

[0316] The bactericide is kason;

[0317] The preparation process is as follows:

[0318] The water, polyethylene glycol, maleic acid, ethanol and ethylene glycol are mixed and stirred for the first time, abrasive grains are added and stirred for the second time, and a bactericide is added and stirred for the third time after adjusting the pH value (the pH value adjusters used are maleic acid and sodium hydroxide) to obtain a polishing liquid;

[0319] The stirring speed of the first stirring is 200 r / min; the time of the first stirring is 40 min; the stirring speed of the second stirring is 200 r / min; the time of the second stirring is 80 min; the stirring speed of the third stirring is 200 r / min; the time of the third stirring is 80 min.

[0320] The polishing process is as follows:

[0321] The polishing liquid was used to polish polysilicon. The pressure during polishing was 3 psi. The polishing liquid used in polishing was diluted 20 times, 30 times, and 40 times, respectively. The relevant indicators of the product obtained by polishing are shown in Table 1.

[0322] Embodiment 46

[0323] This embodiment provides a polishing liquid with a constant removal amount under different dilution multiples, which includes, by mass percentage:

[0324] Abrasive 15%, polyethylene glycol PEG-2000 1%, fungicide 0.1%, methane sulfonic acid 3%, methanol 2.5%, ethylene glycol 0.6%, the balance is water, the pH value of the polishing liquid is 9.5;

[0325] The abrasive particles are spherical silica abrasive particles with a particle size of 55-70 nm;

[0326] The bactericide is BiT-20;

[0327] The preparation process is as follows:

[0328] Mix water, polyethylene glycol, methane sulfonic acid, methanol and ethylene glycol for a first stirring, add abrasive particles for a second stirring, adjust the pH value (the pH value regulator used is methane sulfonic acid and sodium hydroxide), and then add a bactericide for a third stirring to obtain a polishing liquid;

[0329] The stirring speed of the first stirring is 250 r / min; the time of the first stirring is 35 min; the stirring speed of the second stirring is 250 r / min; the time of the second stirring is 70 min; the stirring speed of the third stirring is 250 r / min; the time of the third stirring is 70 min.

[0330] The polishing process is as follows:

[0331] The polishing liquid was used to polish polysilicon. The pressure during polishing was 3.5 psi. The polishing liquid used in polishing was diluted 20 times, 30 times, and 40 times, respectively. The relevant indicators of the product obtained by polishing are shown in Table 1.

[0332] Embodiment 47

[0333] This embodiment provides a polishing liquid with a constant removal amount under different dilution multiples, which includes, by mass percentage:

[0334] Abrasive 10%, polyethylene glycol PEG-1500 0.01%, fungicide 1%, alginic acid 0.1%, methanol 5%, ethylene glycol 1%, the balance is water, the pH value of the polishing liquid is 10;

[0335] The abrasive particles are spherical silica abrasive particles with a particle size of 55-65 nm;

[0336] The bactericide is BiT-20 and Kasong in a mass ratio of 1:1;

[0337] The preparation process is as follows:

[0338] The water, polyethylene glycol, alginic acid, methanol and ethylene glycol are mixed and stirred for the first time, abrasive grains are added and stirred for the second time, and a bactericide is added and stirred for the third time after adjusting the pH value (the pH value regulator used is alginic acid and sodium hydroxide) to obtain a polishing liquid;

[0339] The stirring speed of the first stirring is 150 r / min; the time of the first stirring is 45 min; the stirring speed of the second stirring is 150 r / min; the time of the second stirring is 90 min; the stirring speed of the third stirring is 150 r / min; the time of the third stirring is 90 min.

[0340] The polishing process is as follows:

[0341] The polishing liquid was used to polish polysilicon. The pressure during polishing was 2 psi. The polishing liquid used in polishing was diluted 20 times, 30 times, and 40 times, respectively. The relevant indicators of the product obtained by polishing are shown in Table 1.

[0342] Embodiment 48

[0343] This embodiment provides a polishing liquid with a constant removal amount under different dilution multiples, which includes, by mass percentage:

[0344] Abrasive 30%, polyethylene glycol PEG-1000 5%, bactericide 0.01%, methane sulfonic acid 5%, ethanol 0.1%, ethylene glycol 0.1%, the balance is water, the pH value of the polishing liquid is 9;

[0345] The abrasive particles are spherical silica abrasive particles with a particle size of 50-70 nm;

[0346] The bactericide is kason;

[0347] The preparation process is as follows:

[0348] The water, polyethylene glycol, methane sulfonic acid, ethanol and ethylene glycol are mixed and stirred for the first time, abrasive grains are added and stirred for the second time, and a bactericide is added and stirred for the third time after adjusting the pH value (the pH value regulator used is methane sulfonic acid and sodium hydroxide) to obtain a polishing liquid;

[0349] The stirring speed of the first stirring is 300 r / min; the time of the first stirring is 30 min; the stirring speed of the second stirring is 300 r / min; the time of the second stirring is 60 min; the stirring speed of the third stirring is 250 r / min; and the time of the third stirring is 60 min.

[0350] The polishing process is as follows:

[0351] The polishing liquid was used to polish polysilicon. The pressure during polishing was 4 psi. The polishing liquid used in polishing was diluted 20 times, 30 times, and 40 times, respectively. The relevant indicators of the product obtained by polishing are shown in Table 1.

[0352] Embodiment 49

[0353] The only difference from Example 45 is that the particle size of the abrasive used is 90-100 nm.

[0354] Embodiment 50

[0355] The only difference from Example 45 is that the particle size of the abrasive used is 20-30 nm.

[0356] Embodiment 51

[0357] The only difference from Example 45 is that the polyethylene glycol used is replaced by polyvinyl alcohol (molecular weight 4000).

[0358] Embodiment 52

[0359] The only difference from Example 45 is that the polyethylene glycol used is polyethylene glycol PEG600.

[0360] Embodiment 53

[0361] The only difference from Example 45 is that the polyethylene glycol used is polyethylene glycol PEG200.

[0362] Embodiment 54

[0363] The only difference from Example 45 is that the pH value of the polishing liquid is 8.

[0364] Embodiment 55

[0365] The only difference from Example 45 is that the pH value of the polishing liquid is 11.

[0366] Embodiment 56

[0367] The only difference from Example 45 is that maleic acid is replaced by an equal amount of methanesulfonic acid.

[0368] Embodiment 57

[0369] The only difference from Example 45 is that ethanol is replaced by an equal amount of methanol.

[0370] Embodiment 58

[0371] The only difference from Example 45 is that ethylene glycol is replaced by an equal amount of 1,2-butanediol.

[0372] Embodiment 59

[0373] The only difference from Example 45 is that the mass percentage of abrasive particles in the polishing liquid is 5%.

[0374] Embodiment 60

[0375] The only difference from Example 45 is that the mass percentage of abrasive particles in the polishing liquid is 35%.

[0376] Embodiment 61

[0377] The only difference from Example 45 is that the mass percentage of polyethylene glycol in the polishing liquid is 6%.

[0378] Embodiment 62

[0379] The only difference from Example 45 is that the mass percentage of polyethylene glycol in the polishing liquid is 0.005%.

[0380] The polishing pad used for polishing in the above embodiments and comparative examples is IC1000 polishing pad, the rotation speed of the polishing disc is 93r / min, the rotation speed of the polishing head is 87r / min, the flow rate of the polishing liquid is 200mL / min, and the polishing time is 1min. The results are detailed in Table 4.

[0381] Table 4

[0382]

[0383]

[0384] As can be seen from Table 4, the polishing liquid provided by the present invention, by selecting reasonable polishing liquid components and utilizing the combination of specific abrasive particles, polyethylene glycol, methane sulfonic acid, methanol and ethylene glycol, achieves the effect of keeping the silicon layer removal amount basically unchanged under the same other polishing parameters but different dilution multiples, which is conducive to efficient polishing. At the same time, the removal amount can reach more than 410nm / min, and the surface roughness of the obtained product Ra≤0.51nm.

[0385] The preferred embodiments of the present invention are described in detail above. However, the present invention is not limited to the specific details in the above embodiments. Within the technical concept of the present invention, a variety of simple modifications can be made to the technical solution of the present invention, and these simple modifications all belong to the protection scope of the present invention.

[0386] It should also be noted that the various specific technical features described in the above specific embodiments can be combined in any suitable manner without contradiction. In order to avoid unnecessary repetition, the present invention will not further describe various possible combinations.

[0387] In addition, various embodiments of the present invention may be arbitrarily combined, and as long as they do not violate the concept of the present invention, they should also be regarded as the contents disclosed by the present invention.

Claims

1. A polishing liquid with low roughness and high removal rate, characterized in that: The polishing liquid comprises, by weight percentage: Abrasive 1-30%, surfactant 0.01-10%, first additive 0.1-5%, second additive 0.1-1%, and the balance is water; The first auxiliary agent includes one of polyether, guanidine salt, silane or monohydric alcohol; The second auxiliary agent includes one of cellulose, complexing agent, silicone defoamer or diol; The pH value of the polishing liquid is 9-11.

2. The polishing liquid according to claim 1, characterized in that The particle size of the abrasive particles is 40-90 nm; Preferably, the abrasive particles include spherical abrasive particles; Preferably, the abrasive particles include silicon dioxide abrasive particles; Preferably, the surfactant comprises one of polysorbate, carboxymethyl cellulose, polyvinyl pyrrolidone or polyethylene glycol; Preferably, the polyether comprises polyether F124 and / or polyether F127; Preferably, the guanidine salt comprises one or a combination of at least two of guanidine hydrochloride, guanidine nitrate or guanidine carbonate; Preferably, the silane comprises 3-aminopropylmethyldimethoxysilane and / or 3-aminopropyl(diethoxy)methylsilane; Preferably, the monohydric alcohol comprises methanol and / or ethanol; Preferably, the cellulose comprises carboxymethyl cellulose and / or hydroxyethyl cellulose; Preferably, the complexing agent comprises hydroxyethylidene diphosphonic acid and / or EDTA; Preferably, the diol comprises ethylene glycol.

3. The polishing liquid according to claim 2, characterized in that The polishing liquid comprises, by weight percentage: 5-12% silicon dioxide abrasive, 0.1-10% polysorbate, 0.1-1% polyether F127, 0.1-1% hydroxyethyl cellulose, and the balance is water.

4. The polishing liquid according to claim 2, characterized in that The polishing liquid comprises, by weight percentage: 15-20% silicon dioxide abrasive, 0.1-10% carboxymethyl cellulose, 0.1-3% guanidine nitrate, 0.1-1% hydroxyethylidene diphosphonic acid, and the balance is water.

5. The polishing liquid according to claim 2, characterized in that The polishing liquid comprises, by weight percentage: 1-8% silicon dioxide abrasive, 2-10% polyvinyl pyrrolidone, 0.1-1% 3-aminopropyl (diethoxy) methyl silane, 0.1-1% organic silicon defoamer, and the balance is water.

6. The polishing liquid according to claim 2, characterized in that The polishing liquid comprises, by weight percentage: 10-30% abrasive particles, 0.01-5% polyethylene glycol, 0.1-5% methanol, 0.1-1% ethylene glycol, and the balance is water.

7. The polishing liquid according to any one of claims 1 to 6, characterized in that The polishing liquid also includes: Fungicide 0.1-5%; Preferably, the bactericide comprises BiT-20 and / or Kathon.

8. A method for preparing a polishing liquid according to any one of claims 1 to 7, characterized in that: The preparation method comprises: The ingredients are prepared according to the formula of mass percentage, and then the polishing liquid is obtained by stirring and mixing.

9. Use of the polishing liquid according to any one of claims 1 to 7, characterized in that: The application includes: polishing a silicon wafer using the polishing liquid.

10. The use according to claim 9, characterized in that The polishing pressure is 0.2-4 psi; Preferably, the polishing liquid used in the polishing is diluted 0-50 times.

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