Polysilicon chemical mechanical polishing solution, preparation method and application thereof

Abstract

The application provides a polysilicon chemical mechanical polishing solution, a preparation method and application thereof. The polysilicon chemical mechanical polishing solution contains the following raw material components in parts by weight: abrasive 10-20 parts, pH regulator 0.5-6 parts, inhibitor 0.001-1.0 parts, bactericide 0.001-1.0 parts and water 75-85 parts; the inhibitor is selected from polyoxyethylene fatty alcohol ethers. The chemical mechanical polishing solution provided by the application has the advantages of high surface quality, high process flexibility and real-time response capability, wide-range continuous adjustability and simple operation, and is very suitable for large-scale popularization and application.

Description

Technical Field

[0001] This invention relates to the field of semiconductor processing technology, and in particular to a polycrystalline silicon chemical mechanical polishing slurry, its preparation method, and its application. Background Technology

[0002] Chemical mechanical polishing (CMP) is a core process technology in integrated circuit manufacturing to achieve nanoscale global planarization of wafer surfaces. It mainly uses the synergistic effect of chemical etching and mechanical grinding to remove excess material from the wafer surface and achieve an ultra-flat wafer surface.

[0003] Polysilicon (Poly-Si) is a traditional gate electrode material and hard mask material, and its CMP process directly affects the electrical performance and yield of devices. In the polysilicon CMP process, the polishing slurry not only needs to efficiently and uniformly remove polysilicon material to obtain a high-quality surface, but also needs to achieve precise control of the polishing endpoint to protect the underlying or adjacent sensitive material layers (such as the gate oxide silicon dioxide layer, the shallow trench isolation stop layer silicon nitride layer, etc.), ensuring the electrical performance and yield of the device. This places higher demands on polysilicon chemical mechanical polishing slurries.

[0004] In existing polycrystalline silicon polishing slurries, the polishing selectivity is typically adjusted by changing the content of components. For example, patent CN 101652445 B discloses the use of different amounts and types of polyol-type nonionic surfactants or guanidine compounds to adjust the selectivity ratio of polycrystalline silicon to silicon dioxide; patent CN117567940 B discloses the use of different types and contents of alkaline rate promoters to achieve high selectivity ratios for the removal rates of SiO2 and Si3N4 by polycrystalline silicon. However, adjusting the selectivity ratio by changing the formulation is inconvenient (one formulation corresponds to only one selectivity ratio), complex to operate (requiring the use of different formulations), and costly to manage (storage and management of multiple formulation polishing slurries), resulting in many inconveniences in practical applications.

[0005] Therefore, the question is how to provide a polishing slurry that, when applied to CMP of polycrystalline silicon, not only achieves high surface quality after polishing, but also allows for flexible adjustment of the removal rate and selectivity without changing the slurry formulation. This would combine the advantages of high surface quality, high process flexibility and real-time response, wide range of continuous adjustability, and simple operation. Summary of the Invention

[0006] In view of the shortcomings of the prior art described above, the purpose of this invention is to provide a polycrystalline silicon chemical mechanical polishing slurry, its preparation method and application, to solve the problems in the prior art.

[0007] To achieve the above and other related objectives, the present invention is obtained through the following technical solution.

[0008] The first aspect of the present invention provides a polycrystalline silicon chemical mechanical polishing slurry containing the following raw material components in parts by weight: 10-20 parts of abrasive, 0.5-6 parts of pH adjuster, 0.001-1.0 parts of inhibitor, 0.001-1.0 parts of bactericide, and 75-85 parts of water; wherein the inhibitor is selected from polyoxyethylene fatty alcohol ether.

[0009] The abrasive can be in the form of 10-17.5 parts, 10-15 parts, 15-20 parts, or 15-18 parts; the pH adjuster can be in the form of 0.5-3 parts, 2-3 parts, 0.5-5 parts, 0.1-2 parts, 0.1-3 parts, or 1-4 parts; the inhibitor can be in the form of 0.01-0.1 parts, 0.01-0.03 parts, 0.01-0.05 parts, 0.01-0.08 parts, 0.01-0.2 parts, or 0.01-0.5 parts; and the bactericide can be in the form of 0.001-0.5 parts, 0.001-0.05 parts, 0.001-0.005 parts, or 0.001-0.003 parts. The amount of water can be 75, 76, 77, 78, 79, 80, 81, 82, 83, 84, or 85 parts.

[0010] Preferably, the polycrystalline silicon chemical mechanical polishing slurry contains the following raw material components in parts by weight: 15-20 parts abrasive, 1-5 parts pH adjuster, 0.01-0.1 parts inhibitor, 0.001-0.005 parts bactericide, and 75-85 parts water.

[0011] Preferably, the number average molecular weight of the polyoxyethylene fatty alcohol ether is 1000~1500 g / mol, such as 1100 g / mol, 1200 g / mol, 1300 g / mol, or 1400 g / mol. This is obtained using GPC testing.

[0012] Preferably, the number of oxyethylene vinyl groups in the polyoxyethylene fatty alcohol ether is 18 to 26. For example, it can be 18, 19, 20, 21, 22, 23, 24, 25, or 26.

[0013] The choice of type and molecular weight of the inhibitors added to the polishing slurry in this application affects the polishing effect on polycrystalline silicon. The specific polyoxyethylene fatty alcohol ether selected in this application has a unique polyoxyethylene ether group (-CH2CH2O-) structure. This structure can adsorb onto the silanol groups (Si-OH) or hydration layer on the silicon wafer surface through hydrogen bonding, forming a dense and uniform protective layer on the silicon wafer surface. This physically hinders the direct contact and mechanical removal of abrasive particles (such as silica) in the polishing slurry with the polished surface, which is the basis for achieving high-smoothness polishing. Simultaneously, the specific polyoxyethylene fatty alcohol ether also has a strongly hydrophobic alkyl group, which greatly reduces the adsorption force of abrasive particles on the silicon wafer surface, making it difficult for abrasive particles to adhere firmly. They are also easier to remove in subsequent cleaning steps, thus significantly reducing particle residue after polishing and improving surface quality.

[0014] Meanwhile, adding specific inhibitors to the polishing slurry not only protects the wafer surface but also creates a negative correlation between inhibitor concentration and removal rate (RR): the higher the concentration, the denser the protective film, and the lower the RR. This allows operators to flexibly adjust the dilution ratio according to actual needs; for example, a high concentration can be used to suppress over-polishing in densely patterned areas, while a low concentration can be used to maintain efficiency in flat areas. Compared to existing polishing slurries without inhibitors, whose removal rate is mainly determined by abrasive hardness and particle size, these parameters are difficult to adjust in real time. If the polishing slurry itself has a slow rate, the formulation must be changed, and precise control cannot be achieved through simple dilution.

[0015] Furthermore, if the number-average molecular weight of the polyoxyethylene fatty alcohol ether used is too high or too low, it will be unable to form the dense and uniform protective layer required in this application, and the technical effect of this application will not be achieved. If the number-average molecular weight of the polyoxyethylene fatty alcohol ether used is too high, such as above 2000 g / mol, the protective layer will be too thick, resulting in a significant decrease in the removal rate, reducing production efficiency, and also affecting the polishing quality. If the number-average molecular weight of the polyoxyethylene fatty alcohol ether used is too low, such as below 600 g / mol, its hydrophilicity is weak, and it cannot mix well with the polishing solution, resulting in surface scratches and serious particle residue.

[0016] Preferably, the abrasive is selected from one or more of silicon dioxide, aluminum oxide, aluminum-doped silicon dioxide, aluminum-coated silicon dioxide, and cerium dioxide.

[0017] More preferably, the abrasive is silicon dioxide.

[0018] Preferably, the abrasive particle size is 60~70 nm. For example, it can be 63~68 nm or 62~67 nm.

[0019] Preferably, the abrasive has a shape that includes one or more of peanut-shaped, single-sphere-shaped, and curved shapes, more preferably curved.

[0020] Preferably, the pH adjuster is an alkaline pH adjuster, including one or more of ammonia, tetramethylammonium hydroxide (TMAH), and KOH.

[0021] Preferably, the bactericide is selected from one or more of 1,2-benzisothiazolin-3-one (BIT) and Kathon.

[0022] Preferably, the purity of the abrasive is electronic grade. Specifically, the content of mobile ionic impurities (such as K, Na, Ca, Mg) in the SiO2 abrasive is ≤10 ppb; the content of transition metal impurities (such as Fe, Cu, Zn, Ag, Cr, Ti) is ≤1 ppb; and the content of other metal impurities (such as Pb, Al) is ≤1 ppb.

[0023] Preferably, the purity of the inhibitor is greater than or equal to 99.5%. Specifically, the content of mobile ionic impurities (such as K, Na, Ca, Mg) in the inhibitor (polyoxyethylene fatty alcohol ether) is ≤15ppb; the content of transition metal impurities (such as Fe, Cu, Zn, Ag, Cr, Ti) is ≤1ppb; and the content of other metal impurities (such as Pb, Al) is ≤1ppb.

[0024] Preferably, the purity of the bactericide is greater than or equal to 99.5%. Specifically, the content of mobile ionic impurities (such as K, Na, Ca, Mg) in the bactericide is ≤35ppb; the content of transition metal impurities (such as Fe, Cu, Zn, Ag, Cr, Ti) is ≤1ppb; and the content of other metal impurities (such as Pb, Al) is ≤1ppb.

[0025] Preferably, the purity of the pH adjuster is greater than or equal to 99.5%. Specifically, the content of mobile ion impurities (such as K, Na, Ca, Mg) in the pH adjuster is ≤10 ppb; the content of transition metal impurities (such as Fe, Cu, Zn, Ag, Cr, Ti) is ≤1 ppb; and the content of other metal impurities (such as Pb, Al) is ≤1 ppb.

[0026] Preferably, the pH of the polycrystalline silicon chemical mechanical polishing slurry is 11-12. For example, it can be 11.0, 11.5, or 12.

[0027] Preferably, the content of a single impurity metal ion in the polycrystalline silicon chemical mechanical polishing slurry is ≤50 ppb. For example, it can be ≤30 ppb, ≤20 ppb, or ≤15 ppb.

[0028] Specifically, the chemical mechanical polishing slurry contains ≤15 ppb of K, ≤10 ppb of Na, ≤5 ppb of Ca, ≤2 ppb of Mg, and ≤1 ppb of Al, Ni, Zn, Cu, Fe, Ti, Cr, Pb, and Ag.

[0029] The second aspect of the present invention provides a method for preparing the polycrystalline silicon chemical mechanical polishing slurry as described above, comprising the following steps: mixing the water, pH adjuster, inhibitor, abrasive and bactericide to obtain a mixture, stirring to make the pH of the mixture 11~12, and filtering to obtain the polycrystalline silicon chemical mechanical polishing slurry.

[0030] Preferably, the filtration includes filtration using one or both of a three-stage filter element and a two-stage filter element; the pore size of the three-stage filter element is 0.8~12μm; and the pore size of the two-stage filter element is 0.1~1.2μm.

[0031] More preferably, the filtration includes sequentially using a three-stage filter cartridge and a two-stage filter cartridge.

[0032] Specifically, when using a three-stage filter cartridge, the raw material liquid is filtered sequentially through filter pores of 8~12μm, 2~5μm, and 0.5~1.5μm. More preferably, the pore sizes are 10μm, 3μm, and 1μm.

[0033] Specifically, when using a two-stage filter cartridge, the feed liquid is filtered sequentially through filter pores of 0.5~1.5μm and 0.1~0.5μm. More preferably, the pore sizes are 1μm and 0.3μm.

[0034] Preferably, the stirring speed is 90~110 r / min. For example, the speed can be 95~105 r / min or 98~102 r / min.

[0035] Preferably, the stirring time is 100-150 min; for example, the stirring time is 110-130 min, or 120 min.

[0036] Preferably, the polycrystalline silicon chemical mechanical polishing slurry is diluted with water during use, and the mass ratio of water to polycrystalline silicon chemical mechanical polishing slurry is 1~25:1. For example, it can be 5~20:1, 1~20:1, or 3~20:1.

[0037] Preferably, when the mass ratio of water to polycrystalline silicon chemical mechanical polishing slurry is 1~25:1, the removal rate of polycrystalline silicon can be adjusted within the range of 2000~6000 Å / min. For example, it can be 2500~5500 Å / min, 2500~6000 Å / min, 2000~5500 Å / min, or 2555~5222 Å / min.

[0038] Preferably, when the mass ratio of water to polycrystalline silicon chemical mechanical polishing slurry is 1~25:1, the silicon oxide / silicon nitride removal rate can be adjusted to a range of 5~15 Å / min. For example, it can be 8~13 Å / min, 8~11 Å / min, or 9~11 Å / min.

[0039] Preferably, when the mass ratio of water to polycrystalline silicon chemical mechanical polishing slurry is 1~25:1, the selectivity ratio for removing polycrystalline silicon and silicon oxide / silicon nitride can be adjusted within the range of 100~1200:1. For example, it can be 100~1000:1, 100~800:1, 200~600:1, 200~500:1, or 200~700:1.

[0040] A third aspect of the present invention provides an application of the polycrystalline silicon chemical mechanical polishing slurry as described above in polycrystalline silicon polishing.

[0041] The fourth aspect of the present invention provides the use of polyoxyethylene fatty alcohol ether as a raw material component of polishing liquid to improve the polished surface quality and / or adjust the removal rate during the polishing of polycrystalline silicon.

[0042] The adjustment of removal rate described in this application includes adjusting the removal rate of polysilicon layer, the removal rate of silicon oxide layer, and adjusting the selection ratio of the removal rates of polysilicon layer and silicon oxide layer.

[0043] Preferably, the number average molecular weight of the polyoxyethylene fatty alcohol ether is 1000~1500 g / mol, such as 1100 g / mol, 1200 g / mol, 1300 g / mol, or 1400 g / mol. This is obtained using GPC testing.

[0044] Preferably, the number of oxyethylene vinyl groups in the polyoxyethylene fatty alcohol ether is 18 to 26. For example, it can be 18, 19, 20, 21, 22, 23, 24, 25, or 26.

[0045] Preferably, the content of the polyoxyethylene fatty alcohol ether is 0.001~1.0 wt% based on the total mass of the polishing liquid. For example, it can be 0.01~0.1 wt%, 0.01~0.03 wt%, 0.01~0.05 wt%, 0.01~0.08 wt%, 0.01~0.2 wt%, or 0.01~0.5 wt%.

[0046] Beneficial effects:

[0047] The chemical mechanical polishing slurry provided in this application, when applied to CMP of polycrystalline silicon, not only produces a high surface quality with no more than 10 surface scratches and no more than 10 large particle residues, but also allows for flexible adjustment of the removal rate and selectivity through dilution ratio without changing the slurry formulation. This makes the slurry applicable to a wide range of applications and highly flexible in the polishing process. Furthermore, the slurry has a low gold impurity content, with the content of each single impurity metal ion ≤50ppb, further improving the polishing effect. The slurry provided in this application combines the advantages of high surface quality, high process flexibility and real-time response, wide-range continuous adjustability, and simple operation, making it highly suitable for large-scale promotion and application. Detailed Implementation

[0048] The following specific embodiments illustrate the implementation of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification.

[0049] Before further describing specific embodiments of the present invention, it should be understood that the scope of protection of the present invention is not limited to the specific embodiments described below; it should also be understood that the terminology used in the embodiments of the present invention is for describing specific embodiments and not for limiting the scope of protection of the present invention. Test methods in the following embodiments that do not specify specific conditions are generally performed under conventional conditions or as recommended by the respective manufacturers.

[0050] When numerical ranges are given in the embodiments, it should be understood that, unless otherwise stated in the present invention, both endpoints of each numerical range and any value between the two endpoints may be selected. Unless otherwise defined, all technical and scientific terms used in this invention have the same meaning as commonly understood by one of ordinary skill in the art. In addition to the specific methods, apparatus, and materials used in the embodiments, based on the knowledge of the prior art possessed by one of ordinary skill in the art and the description of this invention, any prior art methods, apparatus, and materials similar to or equivalent to those described, apparatus, and materials in the embodiments of this invention may be used to implement the present invention.

[0051] The polyoxyethylene fatty alcohol ether used in the following embodiments of this application has a number-average molecular weight of 1200 g / mol, wherein the number of oxyethylene groups is 23, and the molecular formula is C. 12 H 25 O·(C2H4O) 23 The solid content of the silica sol is 30~35wt%.

[0052] The content of metal impurities in the abrasive SiO2, inhibitor, pH adjuster and bactericide used in the following embodiments of this application is shown in Table 1 below. The test methods for metal impurities in the abrasive SiO2, preparation, pH adjuster and bactericide are the same, and inductively coupled plasma mass spectrometry (ICP-MS) is used for detection, in accordance with industry standard JC / T 2133-2012.

[0053] Table 1

[0054] Metal impurity content (ppb) <![CDATA[SiO2]]> Inhibitor (polyoxyethylene fatty alcohol ether) pH adjuster bactericide K 10 12 7 30 Na 7 2 3 7 Ca 1 2 1 3 Mg 1 1 ＜1 ＜1 Al ＜1 ＜1 ＜1 ＜1 Ni ＜1 ＜1 ＜1 ＜1 Zn ＜1 ＜1 ＜1 ＜1 Cu ＜1 ＜1 ＜1 ＜1 Fe ＜1 ＜1 ＜1 ＜1 Ti ＜1 ＜1 ＜1 ＜1 Cr 1 ＜1 ＜1 ＜1 Pb ＜1 ＜1 ＜1 ＜1 Ag ＜1 ＜1 ＜1 ＜1

[0055] Example 1

[0056] This embodiment provides a specific polycrystalline silicon chemical mechanical polishing slurry and its preparation method, which specifically includes the following steps:

[0057] Three parts by weight of tetramethyl hydroxide (2.5 vol%), 0.02 parts by weight of polyoxyethylene fatty alcohol ether, 17.5 parts by weight of silica sol (65 nm particle size, tortuous), 0.0015 parts by weight of 1,2-benzisothiazolin-3-one, and 79.5 parts by weight of deionized water were mixed to obtain a mixture. The mixture was stirred at 100 r / min for 120 min. After uniform mixing, the mixture was filtered through a three-stage filter cartridge (with 10 μm, 3 μm, and 1 μm pores) and a two-stage filter cartridge (with 1 μm and 0.3 μm pores) to fully remove impurities and large particles, resulting in a chemical mechanical polishing slurry with a pH of 11.5.

[0058] Example 2

[0059] Except for the use of spherical silica sol, the rest is the same as in Example 1.

[0060] Example 3

[0061] Two parts by weight of tetramethyl hydroxide (2.5 vol%), 0.015 parts by weight of polyoxyethylene fatty alcohol ether, 15 parts by weight of silica sol (65 nm particle size, tortuous), 0.0015 parts by weight of 1,2-benzisothiazolin-3-one, and 79.5 parts by weight of deionized water were mixed to obtain a mixture. The mixture was stirred at 100 r / min for 120 min. After uniform mixing, the mixture was filtered through a three-stage filter cartridge (with 10 μm, 3 μm, and 1 μm pores) and a two-stage filter cartridge (with 1 μm and 0.3 μm pores) to fully remove impurities and large particles, resulting in a chemical mechanical polishing slurry with a pH of 11.0.

[0062] Comparative Example 1

[0063] Except for replacing the polyoxyethylene fatty alcohol ether with fatty alcohol polyoxyethylene ether ammonium sulfate (number average molecular weight of 371 g / mol), the rest is the same as in Example 1.

[0064] Comparative Example 2

[0065] Except for replacing the polyoxyethylene fatty alcohol ether with polyvinylpyrrolidone (PVP-K30, number average molecular weight of 45,000~58,000 g / mol), the rest is the same as in Example 1.

[0066] Comparative Example 3

[0067] Except for the use of polyoxyethylene fatty alcohol ether (polyoxyethylene (60) lauryl ether) with a number average molecular weight of 2810 g / mol, the other parts are the same as in Example 1.

[0068] Comparative Example 4

[0069] Except for the use of polyoxyethylene fatty alcohol ether (Brij-30) with a number average molecular weight of 362.54 g / mol, the other parts are the same as in Example 1.

[0070] Comparative Example 5

[0071] Except for adjusting the pH of the polishing solution to 12.5, the rest of the process is the same as in Example 1.

[0072] Comparative Example 6

[0073] Except for the absence of polyoxyethylene fatty alcohol ether, the rest is the same as in Example 1.

[0074] The applicant conducted metal impurity testing on the chemical mechanical polishing slurries obtained in Examples 1-3 above. The specific testing methods are the same as described above, and the specific test results are shown in Table 2.

[0075] Table 2

[0076] Metal impurity content (ppb) Example 1 Example 2 Example 3 K 10 12 7 Na 7 2 3 Ca 1 2 1 Mg 1 1 ＜1 Al ＜1 ＜1 ＜1 Ni ＜1 ＜1 ＜1 Zn ＜1 ＜1 ＜1 Cu ＜1 ＜1 ＜1 Fe ＜1 ＜1 ＜1 Ti ＜1 ＜1 ＜1 Cr 1 ＜1 ＜1 Pb ＜1 ＜1 ＜1 Ag ＜1 ＜1 ＜1

[0077] As shown in Table 2, the polishing slurry prepared by the technical solution of this application has extremely low metal impurity content, with the content of a single impurity gold ion ≤50ppb. Specifically, the polishing slurry prepared by the technical solution of this application contains K ≤12ppb, Na ≤7ppb, Ca ≤2ppb, Mg ≤1ppb, Al, Ni, Zn, Cu, Fe, Ti, Pb, Ag <1ppb, and Cr ≤1ppb.

[0078] The applicant also used the chemical mechanical polishing (CMP) slurries obtained in Examples 1-3 and Comparative Examples 1-6 for polishing. The polishing parameters were as follows: Horizon 300 polishing equipment, WH6060 polishing pad, polishing head to polishing pad speed ratio of 63 rpm:57 rpm, polishing pressure of 2 psi, polishing time of 1 min, and polishing slurry flow rate of 200 mL / min. The polysilicon gate structure wafer was polished, with excess polysilicon (poly-Si) structure subjected to CMP until the silicon oxide layer (SiO2) on the Fin channel was exposed, until global planarization was achieved. The thickness difference before and after polishing was the corresponding material removal rate. After polishing, a defect re-inspection scanning electron microscope (DR-SEM) was used to detect surface defects and large particle residues on the wafer surface, and the removal rate was measured using an F50-UV film thickness gauge.

[0079] The specific test results are shown in Table 3 below.

[0080] Table 3

[0081] Dilution ratio (water: polishing solution) Polysilicon layer removal rate, Å / min Silica layer removal rate, Å / min <![CDATA[Selectivity ratio poly-Si:SiO2]]> Scratches, stripes Particle residue, particles Example 1 10 4044 9.9 408 3 5 Example 1 5 2555 11 232 3 6 Example 1 20 5222 10.5 497 6 6 Example 2 10 3911 9.5 411 2 5 Example 3 10 4010 9.8 409 2 5 Comparative Example 1 10 3888 9 432 8 142 Comparative Example 2 10 4100 9.5 431 10 150 Comparative Example 3 10 2195 10 219 15 167 Comparative Example 4 10 4982 12.5 399 32 209 Comparative Example 5 10 5288 12.3 430 27 210 Comparative Example 6 10 6012 13 462 42 241

[0082] As shown in Table 3, the polishing slurry provided by this application can be used for polishing. Without changing the formula of the polishing slurry, its selection ratio for the removal rate of polycrystalline silicon layer and silicon oxide layer can be simply adjusted by changing its dilution ratio. Thus, the selection ratio of the polishing slurry can be adjusted according to actual needs. At the same time, with a fixed dilution ratio, it can also achieve high removal rate and surface quality, with fewer surface defects on the wafer, 2 to 6 scratches, and 5 to 6 large particles remaining.

[0083] As can be seen from Examples 1 and Comparative Examples 1-2, when the dilution ratio is the same, the selection of the type of inhibitor polyoxyethylene fatty alcohol ether is very specific. Only by selecting the inhibitor in the technical solution of this application can the technical effect of this application be achieved. If the polyoxyethylene fatty alcohol ether is replaced with fatty alcohol polyoxyethylene ether ammonium sulfate (Comparative Example 1) or polyvinylpyrrolidone (Comparative Example 2), under similar removal rates and selectivity ratios, the surface quality after polishing is poor, and scratches and large particle residues are significantly increased.

[0084] As can be seen from Examples 1 and Comparative Examples 3-4, when the dilution ratio is the same, the number-average molecular weight range of the inhibitor polyoxyethylene fatty alcohol ether is a very important parameter. Only by selecting an inhibitor that meets the technical requirements of this application can the technical effect of this application be achieved. If the number-average molecular weight of the polyoxyethylene fatty alcohol ether used is too high (Comparative Example 3), it will not only significantly reduce the removal rate of the polycrystalline silicon layer and the selectivity ratio of the removal rates of the polycrystalline silicon layer and the silicon oxide layer, thus reducing production efficiency, but also result in poor surface quality after polishing. If the number-average molecular weight of the polyoxyethylene fatty alcohol ether used is too low (Comparative Example 4), under similar removal rates and selectivity ratios, the surface quality after polishing will significantly decrease, and scratches and large particle residues will significantly increase.

[0085] As shown in Example 1 and Comparative Example 5, when the dilution ratio is the same, the pH of the polishing solution is also a very important parameter for the polishing effect, which can affect the surface quality after polishing. If the pH of the polishing solution is slightly higher, exceeding the range of the technical solution of this application, the surface quality after polishing will be significantly reduced, and scratches and large particle residues will be significantly increased, even when the removal rate is basically the same.

[0086] As shown in Example 1 and Comparative Example 6, when the dilution ratio is the same, the addition of inhibitors to the polishing solution affects the polishing effect. If the specific inhibitors of this application are not added, although the removal rate is improved, the surface quality after polishing is significantly affected, resulting in a significant increase in surface scratches and large particle residues.

[0087] The above embodiments are merely illustrative of the principles and effects of the present invention and are not intended to limit the invention. Any person skilled in the art can modify or alter the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or alterations made by those skilled in the art without departing from the spirit and technical concept disclosed in the present invention should still be covered by the claims of the present invention.

Claims

1. A polycrystalline silicon chemical mechanical polishing slurry, characterized in that, The raw material components contain the following parts by weight: 10-20 parts abrasive, 0.5-6 parts pH adjuster, 0.001-1.0 parts inhibitor, 0.001-1.0 parts bactericide, and 75-85 parts water; the inhibitor is selected from polyoxyethylene fatty alcohol ether.

2. The polycrystalline silicon chemical mechanical polishing slurry according to claim 1, characterized in that, The polycrystalline silicon chemical mechanical polishing slurry contains the following raw material components in parts by weight: 15-20 parts abrasive, 1-5 parts pH adjuster, 0.01-0.1 parts inhibitor, 0.001-0.005 parts bactericide, and 75-85 parts water.

3. The polycrystalline silicon chemical mechanical polishing slurry according to claim 1 or 2, characterized in that, The number-average molecular weight of the polyoxyethylene fatty alcohol ether is 1000~1500 g / mol; And / or, the number of oxyethylene groups in the polyoxyethylene fatty alcohol ether is 18 to 26; And / or, the particle size of the abrasive is 60~70nm; And / or, the shape of the abrasive includes one or more of peanut-shaped, single-spherical, and curved shapes; And / or, the abrasive is selected from one or more of silicon dioxide, aluminum oxide, aluminum-doped silicon dioxide, aluminum-coated silicon dioxide, and cerium dioxide; And / or, the pH adjuster is an alkaline pH adjuster, including one or more of ammonia, tetramethylammonium hydroxide and KOH; And / or, the bactericide is selected from one or more of 1,2-benzisothiazolin-3-one and Kathon.

4. The polycrystalline silicon chemical mechanical polishing slurry according to claim 1 or 2, characterized in that, The abrasive is of electronic grade purity; And / or, the purity of the inhibitor is greater than or equal to 99.5%; And / or, the purity of the bactericide is greater than or equal to 99.5%; And / or, the purity of the pH adjuster is greater than or equal to 99.5%; And / or, the pH of the polycrystalline silicon chemical mechanical polishing slurry is 11-12; And / or, the content of a single impurity metal ion in the polycrystalline silicon chemical mechanical polishing slurry is ≤50 ppb.

5. A method for preparing a polycrystalline silicon chemical mechanical polishing slurry as described in any one of claims 1 to 4, characterized in that, The process includes the following steps: mixing the water, pH adjuster, inhibitor, abrasive and bactericide to obtain a mixture, stirring to make the pH of the mixture 11~12, and filtering to obtain the polycrystalline silicon chemical mechanical polishing slurry.

6. The preparation method according to claim 5, characterized in that, The filtration process includes using one or both of a three-stage filter cartridge and a two-stage filter cartridge; the pore size of the three-stage filter cartridge is 0.8~12μm; and the pore size of the two-stage filter cartridge is 0.1~1.2μm. And / or, the stirring speed is 90~110 r / min; And / or, when using, the polycrystalline silicon chemical mechanical polishing slurry is diluted with water, and the mass ratio of water to polycrystalline silicon chemical mechanical polishing slurry is 1~25:

1.

7. The preparation method according to claim 6, characterized in that, The filtration process includes sequential filtration using a three-stage filter cartridge and a two-stage filter cartridge. And / or, when the mass ratio of water to polycrystalline silicon chemical mechanical polishing slurry is 1 to 25:1, the removal rate of polycrystalline silicon can be adjusted in the range of 2000 to 6000 angstroms / min; And / or, when the mass ratio of water to polycrystalline silicon chemical mechanical polishing slurry is 1~25:1, the removal rate of silicon oxide / silicon nitride can be adjusted to a range of 5~15 Å / min; And / or, when the mass ratio of water to polycrystalline silicon chemical mechanical polishing slurry is 1~25:1, the selectivity for removing polycrystalline silicon and silicon oxide / silicon nitride can be adjusted within the range of 100~1200:

1.

8. The application of a polycrystalline silicon chemical mechanical polishing slurry as described in any one of claims 1 to 4 in polycrystalline silicon polishing.

9. The use of a polyoxyethylene fatty alcohol ether as a raw material component of a polishing slurry to improve the surface quality and / or adjust the removal rate during the polishing of polycrystalline silicon.

10. The use according to claim 9, characterized in that, The number-average molecular weight of the polyoxyethylene fatty alcohol ether is 1000~1500 g / mol; And / or, the number of oxyethylene groups in the polyoxyethylene fatty alcohol ether is 18 to 26; And / or, based on the total mass of the polishing liquid, the content of the polyoxyethylene fatty alcohol ether is 0.001~1.0wt%.