Indium phosphide high-efficiency chemical mechanical polishing solution, preparation method and polishing method

Abstract

The invention discloses an efficient indium phosphide chemical mechanical polishing solution, a preparation method and a polishing method, and belongs to the technical field of polishing. The indium phosphide high-efficiency chemical mechanical polishing solution comprises a rough polishing solution and a fine polishing solution, the rough polishing liquid comprises the following components: 2 wt.%-4 wt.% of an oxidizing agent, 8 wt.%-12 wt.% of a silicon dioxide grinding material A, 0.5 wt.%-1.5 wt.% of a dispersing agent and the balance of deionized water; the fine polishing liquid comprises the following components: 7 wt.%-15 wt.% of an oxidizing agent, 6 wt.%-30 wt.% of organic acid, 10 wt.%-30 wt.% of a silicon dioxide abrasive material B, 6 wt.%-15 wt.% of a dispersing agent and the balance of deionized water. The invention relates to an indium phosphide high-efficiency chemical mechanical polishing solution, a preparation method and a polishing method, and solves the problems of low polishing efficiency and poor polishing surface quality of the existing polishing solution on an indium phosphide substrate.

Description

Technical Field

[0001] This invention relates to the field of polishing technology, and in particular to an indium phosphide high-efficiency chemical mechanical polishing slurry, its preparation method, and its polishing method. Background Technology

[0002] Indium phosphide (IP) crystals hold an irreplaceable position in the field of semiconductor materials due to their unique physicochemical properties. Its 1.35 eV bandgap at room temperature perfectly matches the low-loss window required for optical fiber communication, and its electron mobility reaches as high as 4600 cm⁻¹. 2 Its electric field drift velocity (W / (m·K)) is more than five times that of silicon, making it superior in high-frequency devices. Its ideal electric field drift velocity meets the rapid response requirements of high-frequency devices, its strong radiation resistance allows it to operate stably in extreme environments such as aerospace, and its excellent thermal conductivity (70 W / (m·K)) helps dissipate heat and improves operational reliability. For these reasons, it has found wide and important applications in many fields, including optoelectronic devices such as light-emitting diodes (LEDs), optical modules in optoelectronic communications, core components of lasers, high-efficiency radiation-resistant solar cells, and high-frequency, high-speed, broadband, low-noise microwave and millimeter-wave electronic devices.

[0003] In the indium phosphide (IPT) processing flow, the grinding and polishing process is a crucial step determining its final performance. The polishing process of IPT substrates is a complex process involving the combined effects of chemical etching and mechanical grinding; the balance between these two effects directly impacts the polishing result. However, IPT wafers possess inherent characteristics; their Vickers hardness is only 800-1000 MPa, significantly lower than gallium arsenide (1400 MPa) and silicon wafers (1150 MPa), making them highly susceptible to mechanical damage during polishing. Furthermore, most IPT substrates require double-sided polishing, demanding extremely high flatness (TIR < 5 μm), smoothness, and consistency on both surfaces. This undoubtedly increases the difficulty of the polishing process and places extremely stringent requirements on polishing conditions and the performance of the polishing solution. The IPT substrate polishing process must simultaneously meet the technical requirements of high removal rate (≥ 0.1 μm / min), low surface damage (roughness Ra ≤ 0.3 nm), and high selectivity (InP / oxide removal ratio > 5:1). While existing traditional silica-based polishing slurries can achieve low roughness (Ra ≤ 0.25 nm), the removal rate is only 0.8 μm / h, which affects polishing efficiency, and acidic conditions can easily lead to silica residue. Summary of the Invention

[0004] The purpose of this invention is to provide an efficient indium phosphide chemical mechanical polishing slurry, its preparation method, and its polishing method, thereby solving the problems of low polishing efficiency and poor surface quality of existing polishing slurries on indium phosphide substrates.

[0005] To achieve the above objectives, the present invention provides an indium phosphide high-efficiency chemical mechanical polishing slurry, comprising a coarse polishing slurry and a fine polishing slurry; The rough polishing solution comprises the following components by mass percentage: oxidant 2 wt.%-4 wt.%, silica abrasive A 8 wt.%-12 wt.%, dispersant 0.5 wt.%-1.5 wt.%, and balance deionized water; The polishing solution comprises the following components by weight percentage: oxidant 7 wt.%-15 wt.%, organic acid 6 wt.%-30 wt.%, silica abrasive B 10 wt.%-30 wt.%, dispersant 6 wt.%-15 wt.%, and balance deionized water.

[0006] Preferably, the oxidant is hydrogen peroxide, and the mass concentration of hydrogen peroxide is 25%-35%.

[0007] Preferably, the particle size of the silica abrasive A is 50 nm-150 nm, and the mass concentration of the silica abrasive A is 20%-45%.

[0008] Preferably, the particle size of the silica abrasive B is 10 nm-40 nm, and the mass concentration of the silica abrasive B is 20%-36%.

[0009] Preferably, the organic acid in the polishing solution is one or a mixture of several of malic acid, lactic acid, oxalic acid, tartaric acid, or citric acid.

[0010] Preferably, the dispersant is sodium dodecyl sulfonate.

[0011] Preferably, the pH value of the coarse polishing solution is 2-3, and the pH value of the fine polishing solution is 4-6.

[0012] The preparation method of the above-mentioned indium phosphide high-efficiency chemical mechanical polishing slurry includes: To prepare the coarse polishing solution, add hydrogen peroxide oxidant to deionized water according to the mass ratio, stir for 10 min-20 min, then add silica abrasive A and sodium dodecyl sulfonate dispersant in sequence according to the mass ratio, stir for 30 min-60 min, and then filter to obtain the coarse polishing solution. To prepare the polishing solution, add hydrogen peroxide oxidant to deionized water according to the mass ratio, stir for 10 min-20 min, then add organic acid, silica abrasive B and sodium dodecyl sulfonate dispersant in sequence according to the mass ratio, adjust the pH, stir for 30 min-60 min and filter to obtain the polishing solution.

[0013] The polishing method for the above-mentioned indium phosphide high-efficiency chemical mechanical polishing slurry includes the following steps: S1. Use a coarse polishing solution to coarsely polish for 3 min to 8 min at a pressure of 20 kPa-50 kPa and a speed of 80 rpm-140 rpm. The flow rate of the coarse polishing solution is 300 mL / min-800 mL / min. S2. Use a polishing solution to polish for 10-15 minutes at a pressure of 10 kPa-15 kPa and a speed of 60-80 rpm, with a flow rate of 200 mL / min-300 mL / min.

[0014] Preferably, the polishing pads used in the rough and fine polishing processes are acid-resistant, wax-free polyurethane pads with a hardness of Shore D50-60.

[0015] The advantages and positive effects of the indium phosphide high-efficiency chemical mechanical polishing slurry, preparation method, and polishing method described in this invention are as follows: This invention achieves two-step polishing of indium phosphide through a coarse polishing slurry and a fine polishing slurry. Coarse polishing of the indium phosphide substrate is performed using a low-concentration oxidant and large-particle silica abrasive A, rapidly removing processing damage to the substrate surface, improving material removal rate, and thus enhancing polishing efficiency. Under the action of organic acid and small-particle silica abrasive B, combined with the fine polishing process, the surface finish of the indium phosphide substrate is improved, enhancing the polishing effect. The polishing slurry described in this invention has low raw material costs, does not contain chlorine oxidants, is environmentally friendly, safe, and stable; and can meet the precision processing needs of substrates in high-end fields such as optoelectronic devices. Detailed Implementation

[0016] In this application, unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains. In case of any inconsistency, the meaning set forth in this specification or derived from the content described herein shall prevail. Furthermore, the terminology used herein is for the purpose of describing embodiments of this application only and is not intended to limit the scope of this application.

[0017] A high-efficiency chemical mechanical polishing slurry for indium phosphide includes a coarse polishing solution and a fine polishing solution; The coarse polishing solution comprises the following components by mass percentage: oxidant 2 wt.%-4 wt.%, silica abrasive A 8 wt.%-12 wt.%, dispersant 0.5 wt.%-1.5 wt.%, and balance deionized water.

[0018] The polishing solution comprises the following components by weight percentage: oxidant 7 wt.%-15 wt.%, organic acid 6 wt.%-30 wt.%, silica abrasive B 10 wt.%-30 wt.%, dispersant 6 wt.%-15 wt.%, and balance deionized water.

[0019] The oxidant is hydrogen peroxide, with a mass concentration of 25%-35%, preferably 25%-35%. Hydrogen peroxide maintains the continuous oxidation reaction on the surface of the indium phosphide substrate, chemically converting the InP on the substrate surface into an oxide layer that is easily removed mechanically. This provides "easily removable targets" for subsequent mechanical polishing with abrasives, improving polishing efficiency. In the coarse polishing solution, a low concentration of hydrogen peroxide is used. Under the action of low-concentration hydrogen peroxide, a thin oxide layer can be formed on the surface of the indium phosphide substrate. Combined with large-particle-size silica abrasives, the damaged layer on the indium phosphide surface is quickly removed, avoiding excessive oxidation that could lead to substrate surface deterioration. In the fine polishing solution, a high concentration of hydrogen peroxide is used. High-concentration hydrogen peroxide can form a more uniform thin oxide layer on the surface of the indium phosphide substrate. Combined with small-particle-size silica abrasives, nanoscale finishing of the indium phosphide substrate is achieved, improving polishing precision.

[0020] Silica abrasive A has a particle size of 50 nm-150 nm and a mass concentration of 20%-45%. Silica abrasive B has a particle size of 10 nm-40 nm and a mass concentration of 20%-36%. By using larger-diameter silica abrasive particles to impact and shear the oxide and damaged layers on the substrate surface, processing marks are quickly removed, improving the removal rate. Small-diameter silica particles can penetrate deep into microscopic protrusions on the substrate surface, improving the surface finish of the substrate.

[0021] The organic acid in the polishing solution is one or a mixture of several of malic acid, lactic acid, oxalic acid, tartaric acid, or citric acid. The pH value of the polishing solution is adjusted by the organic acid to control the chemical corrosion rate and avoid excessive corrosion that could lead to surface roughness or corrosion marks. Simultaneously, it avoids silicone residue caused by a highly acidic environment and reduces corrosion of the polishing pad.

[0022] The dispersant is sodium dodecyl sulfonate. Sodium dodecyl sulfonate forms a charge repulsion on the silica surface through the action of a surfactant, maintaining the uniform dispersion of the abrasive in the polishing slurry.

[0023] The pH value of the coarse polishing solution is 2-3, and the pH value of the fine polishing solution is 4-6.

[0024] A method for preparing an indium phosphide high-efficiency chemical mechanical polishing slurry includes: To prepare the coarse polishing solution, add hydrogen peroxide oxidant to deionized water according to the mass ratio, stir for 10 min-20 min, then add silica abrasive A and sodium dodecyl sulfonate dispersant in sequence according to the mass ratio, stir for 30 min-60 min, and then filter to obtain the coarse polishing solution.

[0025] To prepare the polishing solution, add hydrogen peroxide oxidant to deionized water according to the mass ratio, stir for 10 min-20 min, then add organic acid, silica abrasive B and sodium dodecyl sulfonate dispersant in sequence according to the mass ratio, adjust the pH, stir for 30 min-60 min and filter to obtain the polishing solution.

[0026] A polishing method using indium phosphide high-efficiency chemical mechanical polishing slurry includes the following steps: S1. Use a coarse polishing solution to perform coarse polishing for 3 min to 8 min at a pressure of 20 kPa-50 kPa and a speed of 80 rpm-140 rpm. The flow rate of the coarse polishing solution is 300 mL / min-800 mL / min.

[0027] S2. Use a polishing solution to polish for 10-15 minutes at a pressure of 10 kPa-15 kPa and a speed of 60-80 rpm, with a flow rate of 200 mL / min-300 mL / min.

[0028] The polishing pads used in the rough and fine polishing processes are acid-resistant, wax-free polyurethane pads with a hardness of Shore D 50-60.

[0029] Indium phosphide substrates are polished using coarse polishing and fine polishing methods. The coarse polishing solution increases the polishing rate of the substrate, while the fine polishing solution improves the flatness and smoothness of the substrate surface. This improves the polishing efficiency of indium phosphide substrates while ensuring the polishing quality.

[0030] Example 1 The weight percentages of the components in the coarse polishing solution are as follows: 2% hydrogen peroxide, mass concentration 30%; 8% silica abrasive A, particle size 100 nm, mass concentration 35%; 0.5% sodium dodecyl sulfonate; and the remainder is deionized water. After stirring for a period of time, a sample was taken and the pH value was measured to be 2.5.

[0031] The weight percentages of the components in the polishing solution are as follows: 8% hydrogen peroxide, mass concentration 30%; 10% malic acid; 15% silica abrasive B, particle size 20 nm, mass concentration 25%; 10% sodium dodecyl sulfonate; and the remainder is deionized water. After stirring for a period of time, a sample was taken and the pH value was measured to be 4.5.

[0032] The rough polishing stage aims to quickly remove most of the processing damage layer from the surface of the indium phosphide substrate, improving material removal efficiency. The pressure in this stage is set at 20 kPa, which ensures sufficient contact between the polishing pad and the substrate surface while preventing excessive pressure that could damage the substrate. The polishing head rotates at 90 rpm, and the polishing disc rotates at 80 rpm. Through their coordinated rotation, effective shear force is generated on the substrate surface, accelerating material removal. The polishing fluid flow rate is controlled at 300 mL / min; sufficient flow effectively removes debris and heat generated during polishing, maintaining a stable polishing environment. The polishing time is 5-8 minutes, which can be flexibly adjusted according to the initial surface condition of the substrate to ensure the expected material removal volume is achieved.

[0033] The fine polishing stage focuses on improving the flatness and smoothness of the substrate surface, providing a high-quality substrate for subsequent semiconductor processes. The pressure is set to 15 kPa, lower than the coarse polishing pressure, to reduce mechanical damage to the substrate surface. The rotation speed is reduced to 60 rpm; this lower speed allows for a gentler polishing process, facilitating finer surface treatment. The flow rate is adjusted to 200 mL / min to ensure effective polishing while avoiding excessive flow that could lead to splashing and waste. The polishing time is 15 minutes; this extended period of fine polishing achieves the desired surface quality.

[0034] Following the two-step chemical mechanical polishing process of roughing and fine polishing described above, the indium phosphide substrate achieved excellent polishing results. The surface roughness Ra reached 0.16 nm. The material removal rate was 0.18 μm / min in the roughing stage and 0.05 μm / min in the fine polishing stage.

[0035] Example 2 The components of the coarse polishing solution by weight percentage are: 2.5% hydrogen peroxide, mass concentration 30%; 10% silica abrasive A, particle size 110 nm, mass concentration 38%; 0.4% sodium dodecyl sulfonate; and the remainder is deionized water. After stirring for a period of time, a sample was taken and the pH value was measured to be 2.4.

[0036] The weight percentages of the components in the polishing solution are as follows: 7.5% hydrogen peroxide, mass concentration 30%; 11% tartaric acid; 16% silica abrasive B, particle size 25 nm, mass concentration 28%; 9% sodium dodecyl sulfonate; and the remainder is deionized water. After stirring for a period of time, a sample was taken and the pH value was measured to be 4.6.

[0037] The rough polishing stage aims to quickly remove most of the processing damage layer from the surface of the indium phosphide substrate, improving material removal efficiency. The pressure in this stage is set at 19 kPa, a pressure range that ensures sufficient contact between the polishing pad and the substrate surface while avoiding excessive pressure that could damage the substrate. The polishing head rotates at 85 rpm, and the polishing disc rotates at 75 rpm. Through their coordinated rotation, effective shear force is generated on the substrate surface, accelerating material removal. The polishing fluid flow rate is controlled at 280 mL / min; sufficient flow effectively removes debris and heat generated during polishing, maintaining a stable polishing environment. The polishing time is 5-7 minutes, which can be flexibly adjusted according to the initial surface condition of the substrate to ensure the expected material removal volume is achieved.

[0038] The fine polishing stage focuses on improving the flatness and smoothness of the substrate surface, providing a high-quality substrate for subsequent semiconductor processes. The pressure is set to 14 kPa, lower than the coarse polishing pressure, to reduce mechanical damage to the substrate surface. The rotation speed is reduced to 55 rpm (polishing head) and 45 rpm (polishing disc); lower speeds allow for a gentler polishing process, facilitating finer surface treatment. The flow rate is adjusted to 190 mL / min to ensure effective polishing while avoiding excessive flow that could lead to splashing and waste. The polishing time is 14 minutes, achieving the desired surface quality through a longer period of fine polishing.

[0039] Following the two-step chemical mechanical polishing process of roughing and fine polishing described above, the indium phosphide substrate achieved excellent polishing results. The surface roughness Ra reached 0.18 nm, meeting the stringent requirements for substrate surface flatness in high-end semiconductor device manufacturing. The material removal rate was 0.16 μm / min in the roughing stage and 0.06 μm / min in the fine polishing stage.

[0040] Example 3 The components of the coarse polishing solution by weight percentage are: 3% hydrogen peroxide, mass concentration 30%; 12% silica abrasive A, particle size 120 nm, mass concentration 40%; 0.6% sodium dodecyl sulfonate; and the remainder is deionized water. After stirring for a period of time, a sample was taken and the pH value was measured to be 2.2.

[0041] The weight percentages of the components in the polishing solution are as follows: 9% hydrogen peroxide, 30% by mass; 12% citric acid; 18% silica abrasive B, 15 nm particle size, 30% by mass; 11% sodium dodecyl sulfonate; and the remainder is deionized water. After stirring for a period of time, a sample was taken and the pH value was measured to be 4.2.

[0042] The rough polishing stage aims to quickly remove most of the processing damage layer from the surface of the indium phosphide substrate, improving material removal efficiency. The pressure in this stage is set at 22 kPa, which ensures sufficient contact between the polishing pad and the substrate surface while preventing excessive pressure that could damage the substrate. The polishing head rotates at 95 rpm, and the polishing disc rotates at 85 rpm. Their coordinated rotation creates effective shear force on the substrate surface, accelerating material removal. The polishing fluid flow rate is controlled at 320 mL / min; this sufficient flow rate effectively removes debris and heat generated during polishing, maintaining a stable polishing environment. The polishing time is 6-9 minutes, which can be flexibly adjusted according to the initial surface condition of the substrate to ensure the expected material removal volume is achieved.

[0043] The fine polishing stage focuses on improving the flatness and smoothness of the substrate surface, providing a high-quality substrate for subsequent semiconductor processes. The pressure is set to 16 kPa, lower than the coarse polishing pressure, to reduce mechanical damage to the substrate surface. The rotation speed is reduced to 65 rpm (polishing head) and 55 rpm (polishing disc); lower speeds allow for a gentler polishing process, facilitating finer surface treatment. The flow rate is adjusted to 210 mL / min to ensure effective polishing while avoiding excessive flow that could lead to splashing and waste. The polishing time is 16 minutes, achieving the desired surface quality through a longer, finer polishing period.

[0044] The indium phosphide substrate achieved excellent polishing results through the two-step chemical mechanical polishing process described above, consisting of rough polishing and fine polishing. The surface roughness Ra reached 0.14 nm. The material removal rate was 0.20 μm / min in the rough polishing stage and 0.07 μm / min in the fine polishing stage.

[0045] Example 4 The components of the coarse polishing solution by weight percentage are: 4% hydrogen peroxide, mass concentration 30%; 10% silica abrasive A, particle size 130 nm, mass concentration 40%; 0.8% sodium dodecyl sulfonate; and the remainder is deionized water. After stirring for a period of time, the pH value was measured to be 2.7.

[0046] The weight percentages of the components in the polishing solution are as follows: 12% hydrogen peroxide, mass concentration 30%; 10% malic acid, 10% oxalic acid; 20% silica abrasive B, particle size 10 nm, mass concentration 35%; 15% sodium dodecyl sulfonate, and the remainder is deionized water. After stirring for a period of time, the pH value was measured to be 4.5.

[0047] Rough Polishing Parameters: In chemical mechanical polishing (CMP), the process parameters of the rough polishing stage play a crucial role in the initial processing effect of indium phosphide substrates. A pressure of 50 kPa is applied to ensure polishing efficiency while avoiding additional damage to the substrate due to excessive pressure. A rotation speed of 120 rpm ensures sufficient contact and effective action of the polishing slurry with the substrate surface. A flow rate of 600 mL / min ensures a constant supply of fresh polishing slurry to the polishing area, maintaining a stable polishing environment. The polishing time is 5 minutes to achieve efficient removal of thick damaged layers.

[0048] Fine polishing parameters: The fine polishing stage focuses on improving the flatness and smoothness of the substrate surface, providing a high-quality substrate for subsequent semiconductor processes. The pressure is set to 17 kPa, lower than the coarse polishing pressure, to reduce mechanical damage to the substrate surface. The rotation speed is reduced to 70 rpm (polishing head) and 60 rpm (polishing disc). Lowering the speed makes the polishing process gentler and helps achieve a finer surface finish. The flow rate is adjusted to 230 mL / min to ensure the effective action of the polishing slurry while avoiding excessive flow that could lead to splashing and waste. The polishing time is 17 min, achieving the desired surface quality through a longer period of fine polishing.

[0049] Following the two-step chemical mechanical polishing process of roughing and fine polishing described above, the indium phosphide substrate achieved excellent polishing results. The surface roughness Ra was further improved to 0.08 nm, meeting the stringent requirements for substrate surface flatness in high-end semiconductor device manufacturing. The material removal rate was 0.22 μm / min in the roughing stage and 0.08 μm / min in the fine polishing stage.

[0050] Comparative Example 1 The components of the coarse polishing solution by weight percentage are: 2% hydrogen peroxide, mass concentration 30%; 8% silicon carbide abrasive A, particle size 180 nm, mass concentration 45%; 0.5% sodium dodecyl sulfonate, the remainder being deionized water. After stirring for a period of time, a sample was taken and the pH value was measured to be 2.5.

[0051] The weight percentages of the components in the polishing solution are as follows: 8% hydrogen peroxide, 30% by mass; 10% malic acid; 15% silicon carbide abrasive B, 40 nm in particle size, 25% by mass; 10% sodium dodecyl sulfonate; and the remainder is deionized water. After stirring for a period of time, a sample was taken and the pH value was measured to be 4.5.

[0052] The rough polishing stage aims to quickly remove the processing damage layer on the surface of the indium phosphide substrate. The pressure is set at 20 kPa, the polishing head speed is 90 rpm, the polishing disc speed is 80 rpm, the polishing fluid flow rate is 300 mL / min, and the polishing time is 5-8 min (consistent with the process parameters in Example 1). However, because silicon carbide abrasives are harder than silicon dioxide and have a larger particle size, they are prone to causing mechanical scratches on the substrate surface during polishing.

[0053] In the fine polishing stage, attempts were made to improve surface smoothness. The pressure was set to 15 kPa, the rotation speed was reduced to 60 rpm, the flow rate was 200 mL / min, and the polishing time was 15 min (consistent with the process parameters in Example 1). However, the particle size of silicon carbide abrasive B was still larger than that of silicon dioxide abrasive B in Example 1, making it difficult to achieve fine surface repair.

[0054] After two-step polishing, the indium phosphide substrate showed poor polishing results. The surface roughness Ra reached 0.42 nm, which is much higher than the 0.16 nm in Example 1, failing to meet the surface flatness requirements of high-end semiconductor devices. Although the material removal rate increased to 0.22 μm / min in the rough polishing stage, obvious scratches appeared on the substrate surface (scratch depth 0.3-0.5 μm). In the fine polishing stage, the material removal rate dropped to 0.05 μm / min, and a small amount of silicon carbide abrasive particles remained on the surface, compromising the substrate's reliability.

[0055] Comparative Example 2 The weight percentages of each component in the coarse polishing solution were exactly the same as in Example 1: 2% hydrogen peroxide, mass concentration 30%; 8% silica abrasive A, particle size 100 nm, mass concentration 35%; 0.5% sodium dodecyl sulfonate, the remainder being deionized water. After stirring for a period of time, a sample was taken and the pH value was measured to be 2.5.

[0056] The weight percentages of each component in the polishing solution were exactly the same as in Example 1: 8% hydrogen peroxide, mass concentration 30%; 10% malic acid; 15% silica abrasive B, particle size 20 nm, mass concentration 25%; 10% sodium dodecyl sulfonate; and the remainder was deionized water. After stirring for a period of time, a sample was taken and the pH value was measured to be 4.5.

[0057] In the rough polishing stage, to achieve higher removal efficiency, the pressure was increased to 30 kPa (higher than 20 kPa in Example 1), the polishing head speed was 120 rpm, the polishing disc speed was 100 rpm (both higher than in Example 1), the polishing fluid flow rate was 300 mL / min, and the polishing time was 10-12 min (longer than in Example 1). Excessive pressure and speed caused the polishing pad to excessively compress the substrate and generate excessive shear force, which easily led to damage to the substrate edges.

[0058] During the fine polishing stage, the pressure was not adjusted and remained at 20 kPa (higher than 15 kPa in Example 1), the rotation speed was 70 rpm (higher than 60 rpm in Example 1), the flow rate was 150 mL / min (lower than 200 mL / min in Example 1), and the polishing time was 12 min (shorter than Example 1). The low flow rate could not remove heat in time, and the high rotation speed aggravated surface friction damage.

[0059] After polishing, the surface quality of the indium phosphide substrate significantly decreased. The surface roughness Ra reached 0.38 nm, and the material removal rate in the rough polishing stage was 0.25 μm / min, but about 15% of the substrates showed edge chipping (chipping width 0.1-0.2 mm); in the fine polishing stage, the material removal rate was 0.07 μm / min, and the surface showed oxidation damage marks due to heat accumulation, and there were also localized polishing pad debris residues, which could not meet the requirements of subsequent chip manufacturing.

[0060] Comparative Example 3 The weight percentages of the components in the coarse polishing solution were as follows: 1% hydrogen peroxide, mass concentration 30% (lower than 2% in Example 1); 8% silica abrasive A, particle size 100 nm, mass concentration 35%; the remainder was deionized water, and no sodium dodecyl sulfonate was added. After stirring for a period of time, a sample was taken and the pH value was measured to be 2.8.

[0061] The weight percentages of the components in the polishing solution were as follows: 7% hydrogen peroxide, mass concentration 30% (lower than 8% in Example 1); 5% malic acid (lower than 10% in Example 1); 15% silica abrasive B, particle size 25 nm, mass concentration 25%; 10% sodium dodecyl sulfonate, the remainder being deionized water. After stirring for a period of time, a sample was taken and the pH value was measured to be 5.2.

[0062] The process parameters for the rough polishing stage were the same as in Example 1: pressure 20 kPa, polishing head speed 90 rpm, polishing disc speed 80 rpm, flow rate 300 mL / min, and time 5-8 min. However, insufficient hydrogen peroxide concentration weakened the chemical corrosion effect, and the lack of sodium dodecyl sulfonate reduced the abrasive dispersion and decreased the material removal efficiency.

[0063] The process parameters for the fine polishing stage were the same as in Example 1: pressure 15 kPa, rotation speed 60 rpm, flow rate 200 mL / min, and time 15 min. However, the reduced malic acid concentration decreased the buffering capacity of the polishing solution, and the pH value deviated from the optimal range, affecting the surface smoothness repair effect.

[0064] After polishing, the indium phosphide substrate showed poor polishing results. The surface roughness Ra reached 0.51 nm, which was much higher than that of Example 1. The material removal rate in the rough polishing stage was only 0.12 μm / min (lower than 0.18 μm / min in Example 1), and the processing efficiency was significantly reduced. The material removal rate in the fine polishing stage was 0.04 μm / min, and a residual oxide layer (0.08-0.1 μm thick) remained on the substrate surface, requiring additional treatment before subsequent processes, which increased production costs.

[0065] Therefore, the high-efficiency indium phosphide chemical mechanical polishing slurry, preparation method and polishing method described in this invention can solve the problems of low polishing efficiency and poor polished surface quality of existing polishing slurries on indium phosphide substrates.

[0066] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit them. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can still be made to the technical solutions of the present invention, and these modifications or equivalent substitutions cannot cause the modified technical solutions to deviate from the spirit and scope of the technical solutions of the present invention.

Claims

1. A high-efficiency chemical mechanical polishing slurry for indium phosphide, characterized in that, Including rough polishing solution and fine polishing solution; The coarse polishing solution comprises the following components by mass percentage: oxidant 2 wt.%-4 wt.%, silica abrasive A 8 wt.%-12 wt.%, dispersant 0.5 wt.%-1.5 wt.%, and balance deionized water; The polishing solution comprises the following components by weight percentage: oxidant 7 wt.%-15 wt.%, organic acid 6 wt.%-30 wt.%, silica abrasive B 10 wt.%-30 wt.%, dispersant 6 wt.%-15 wt.%, and balance deionized water.

2. The indium phosphide high-efficiency chemical mechanical polishing slurry according to claim 1, characterized in that: The oxidant is hydrogen peroxide, and the mass concentration of hydrogen peroxide is 25%-35%.

3. The indium phosphide high-efficiency chemical mechanical polishing slurry according to claim 1, characterized in that: The particle size of the silica abrasive A is 50 nm-150 nm, and the mass concentration of silica abrasive A is 20%-45%.

4. The indium phosphide high-efficiency chemical mechanical polishing slurry according to claim 1, characterized in that: The particle size of the silica abrasive B is 10 nm-40 nm, and the mass concentration of the silica abrasive B is 20%-36%.

5. The indium phosphide high-efficiency chemical mechanical polishing slurry according to claim 1, characterized in that: The organic acid in the polishing solution is one or a mixture of several of malic acid, lactic acid, oxalic acid, tartaric acid, or citric acid.

6. The indium phosphide high-efficiency chemical mechanical polishing slurry according to claim 1, characterized in that: The dispersant is sodium dodecyl sulfonate.

7. The indium phosphide high-efficiency chemical mechanical polishing slurry according to claim 1, characterized in that: The pH value of the coarse polishing solution is 2-3, and the pH value of the fine polishing solution is 4-6.

8. A method for preparing an indium phosphide high-efficiency chemical mechanical polishing slurry as described in any one of claims 1-7, characterized in that, include: To prepare the coarse polishing solution, add hydrogen peroxide oxidant to deionized water according to the mass ratio, stir for 10 min-20 min, then add silica abrasive A and sodium dodecyl sulfonate dispersant in sequence according to the mass ratio, stir for 30 min-60 min, and then filter to obtain the coarse polishing solution. To prepare the polishing solution, add hydrogen peroxide oxidant to deionized water according to the mass ratio, stir for 10 min-20 min, then add organic acid, silica abrasive B and sodium dodecyl sulfonate dispersant in sequence according to the mass ratio, adjust the pH, stir for 30 min-60 min and filter to obtain the polishing solution.

9. A polishing method using the indium phosphide high-efficiency chemical mechanical polishing slurry according to any one of claims 1-7, characterized in that, Includes the following steps: S1. Use a coarse polishing solution to coarsely polish for 3 min to 8 min at a pressure of 20 kPa-50 kPa and a speed of 80 rpm-140 rpm. The flow rate of the coarse polishing solution is 300 mL / min-800 mL / min. S2. Use a polishing solution to polish for 10-15 minutes at a pressure of 10 kPa-15 kPa and a speed of 60-80 rpm, with a flow rate of 200 mL / min-300 mL / min.

10. A polishing method according to claim 9, characterized in that: The polishing pads used in the rough and fine polishing processes are acid-resistant, wax-free polyurethane pads with a hardness of Shore D 50-60.