Chemical polishing solution and polishing method for effectively reducing corrosion pits on surface of indium antimonide single crystal wafer

Abstract

The invention relates to a chemical polishing solution for effectively reducing corrosion pits on the surface of an indium antimonide single crystal wafer and a polishing method, and belongs to the technical field of photoelectric materials. The chemical polishing solution is a mixed solution of hydrogen peroxide, phosphoric acid and water, and specific components of the chemical polishing solution are strictly limited; the polishing method provides the application of the chemical polishing solution in different stages in the chemical polishing process of the surface of the indium antimonide single crystal wafer. By adopting the chemical polishing solution and the polishing method, secondary defects caused in the polishing process can be effectively avoided, corrosion pits on the surface of the indium antimonide single crystal wafer are reduced, and preparation of perfect crystal lattices of the indium antimonide single crystal wafer is realized; the yield of the infrared detector prepared from the indium antimonide single crystal wafer polished by the polishing solution and the polishing method is greatly improved, and the application range of the indium antimonide single crystal wafer on the infrared detector is greatly widened.

Description

Technical Field

[0001] The invention relates to a chemical polishing liquid and a polishing method for effectively reducing corrosion pits on the surface of an indium antimonide single crystal wafer, belonging to the technical field of photoelectric materials. Background Art

[0002] InSb has a high quantum efficiency in the 3μm to 5μm band. InSb has the advantages of low cost and stable performance in the preparation of infrared detectors. InSb infrared detectors have broad prospects in military and civilian applications and have attracted more and more attention. With the large-scale development of InSb infrared focal plane array devices, the factors that restrict the uniformity, yield and cost of the array are no longer the quality and size of the InSb material itself, but the damage and flatness of the surface of the InSb wafer. In order to improve the reliability and yield of InSb infrared focal plane array devices, the research and development of surface treatment technology with no surface damage and high flatness (<10μm) is crucial.

[0003] At present, the surface treatment method of indium antimonide wafers is mainly mechanical grinding and polishing: the ingot is sliced ​​and fixed, and the wafer flatness is improved by grinding, rough polishing and fine polishing, while obtaining a bright "mirror" effect to meet the needs of subsequent production. However, since grinding occurs under the combined action of abrasives of a certain particle size and pressure, that is, the surface of the material is removed by the mechanical grinding action of abrasives and grinding discs on the surface of indium antimonide crystals, it is inevitable that certain surface damage will occur. At the same time, the polishing liquid currently used is generally SiO 2 A solution of colloidal aqueous solvent and hydrogen peroxide additive, SiO 2 The particle size is 0.05μm. Although the particle size is small, the presence of particles will introduce new damage during the polishing process. After polishing, the surface of the wafer looks bright, but there are dark damages hidden under the surface. After etching, it can be seen that there are many corrosion pits with a diameter greater than 20μm, more than 50 / cm 2 At the same time, the back is also covered with small corrosion pits. The existence of the damaged layer will not only increase the device noise, but also increase the density of surface dangling bonds, resulting in enhanced surface adsorption, making it easier to adsorb impurity ions, resulting in a decrease in electrical performance and an increase in leakage current, which seriously affects the performance of the device. Summary of the invention

[0004] In view of the defects in the surface treatment technology of indium antimonide single wafers in the prior art, the purpose of the present invention is to provide a chemical polishing liquid and a polishing method for effectively reducing corrosion pits on the surface of indium antimonide single wafers; through a chemical polishing liquid with specific components and the application of the chemical polishing liquid at different stages in the chemical polishing process of the surface of indium antimonide single wafers, the corrosion pits on the surface of indium antimonide single wafers are effectively reduced.

[0005] To achieve the purpose of the present invention, the following technical solutions are provided.

[0006] A chemical polishing solution for effectively reducing corrosion pits on the surface of an indium antimonide single crystal wafer, wherein the chemical polishing solution is a mixed solution of hydrogen peroxide, phosphoric acid and water;

[0007] When used as a rough polishing chemical polishing liquid: the volume ratio of hydrogen peroxide, phosphoric acid and water is 2:1:6, and the pH is 3-5;

[0008] When used as the first fine polishing chemical polishing liquid: the volume ratio of hydrogen peroxide, phosphoric acid and water is 1:1:6, and the pH is 3-5;

[0009] When used as the second fine polishing chemical polishing liquid: the volume ratio of hydrogen peroxide, phosphoric acid and water is 0.5:1:6, and the pH is 3-5;

[0010] The phosphoric acid used in preparing the chemical polishing solution is UP grade phosphoric acid.

[0011] When preparing the chemical polishing liquid, preferably, phosphoric acid is dissolved in water and stirred evenly to prepare a phosphoric acid solution, and then hydrogen peroxide is added under continuous stirring to prepare the chemical polishing liquid;

[0012] Preferably, hydrogen peroxide is added to a phosphoric acid solution with a mass fraction of 8% to 15% under continuous stirring to prepare a rough polishing chemical polishing solution, hydrogen peroxide is added to a phosphoric acid solution with a mass fraction of 4% to 8% under continuous stirring to prepare a first fine polishing chemical polishing solution, and hydrogen peroxide is added to a phosphoric acid solution with a mass fraction of 2% to 4% under continuous stirring to prepare a second fine polishing chemical polishing solution.

[0013] Furthermore, during the preparation of the chemical polishing liquid, magnetic stirring is used for stirring, and a temperature control system is used to control the temperature, so that the components in the chemical polishing liquid are fully mixed and uniformly and the temperature is kept constant.

[0014] A polishing method for effectively reducing corrosion pits on the surface of an indium antimonide single crystal wafer, the method steps are as follows:

[0015] (1) Rough polishing

[0016] The 800 μm thick indium antimonide single crystal was bonded and fixed to a rough polishing disc, and rough polishing and thinning was performed using the rough polishing chemical polishing solution of the present invention. The specific conditions were: the rotation speed of the polishing disc was 70 r / min to 80 r / min, and the pressure was 10 g / cm 2 ~15g / cm 2The dripping rate of the rough polishing chemical polishing liquid is 20 drops / min to 30 drops / min. The thickness of the indium antimonide single crystal after rough polishing is 625μm to 675μm. When the flatness meets the technical requirements, it is turned to fine polishing.

[0017] (2) First fine polishing

[0018] The indium antimonide single crystal wafer after rough polishing is loaded into a precision polishing machine, and the first fine polishing chemical polishing liquid of the present invention is used for the first fine polishing. The specific conditions are: the speed of the polishing disc is 20r / min-30r / min, the pressure is 5g / cm 2 ~10g / cm 2 The dripping rate of the chemical polishing liquid for the first fine polishing is 10 drops / min to 20 drops / min, and the polishing time is 3h to 5h, and an indium antimonide single crystal wafer after the first fine polishing is obtained.

[0019] (3) Second fine polishing

[0020] The indium antimonide single crystal wafer after the first fine polishing is subjected to a second fine polishing using the second fine polishing chemical polishing solution of the present invention. The specific conditions are: the rotation speed of the polishing disc is 20r / min-30r / min, the pressure is 5g / cm 2 ~10g / cm 2 The dripping rate of the chemical polishing liquid for the second fine polishing is 10 drops / min to 20 drops / min, and the polishing time is 1h to 2h. The indium antimonide single crystal wafer after the second fine polishing is obtained, and the polishing is completed.

[0021] The water described in the present invention is water with a purity higher than that of deionized water, for example, deionized water and ultrapure water.

[0022] Beneficial Effects

[0023] (1) The present invention provides a chemical polishing solution that effectively reduces corrosion pits on the surface of an indium antimonide single crystal wafer, wherein the chemical polishing solution is a mixed solution of hydrogen peroxide, phosphoric acid and water;

[0024] When used as a rough polishing chemical polishing liquid, the volume ratio of hydrogen peroxide, phosphoric acid and water is 2:1:6, and the pH is 3-5; when used as a first fine polishing chemical polishing liquid, the volume ratio of hydrogen peroxide, phosphoric acid and water is 1:1:6, and the pH is 3-5; when used as a second fine polishing chemical polishing liquid, the volume ratio of hydrogen peroxide, phosphoric acid and water is 0.5:1:6, and the pH is 3-5; by regulating the components of the chemical polishing liquid during the surface treatment of the indium antimonide single crystal wafer, the perfect lattice of the indium antimonide single crystal wafer is achieved, a method is provided that can effectively avoid secondary defects and process a perfect indium antimonide single crystal wafer, and fills the gap in the field of precision processing of perfect indium antimonide single crystal wafers.

[0025] (2) The present invention provides a chemical polishing liquid that effectively reduces corrosion pits on the surface of an indium antimonide single crystal wafer. Preferably, magnetic stirring is used for stirring, and a temperature control system is used to control the temperature, so that the components in the chemical polishing liquid can be fully mixed and the temperature can be kept constant.

[0026] (3) The present invention provides a polishing method for effectively reducing corrosion pits on the surface of an InSb2 single crystal wafer. The method achieves a perfect lattice of the InSb2 single crystal wafer by regulating the components of a chemical polishing solution during the surface treatment of the InSb2 single crystal wafer, thereby providing a method for effectively avoiding secondary defects and processing a perfect InSb2 single crystal wafer, thus filling a gap in the field of precision processing of perfect InSb2 single crystal wafers.

[0027] (4) The present invention provides a polishing method for effectively reducing corrosion pits on the surface of an indium antimonide single crystal wafer. The surface of the indium antimonide single crystal wafer polished by the method is observed under a microscope with a magnification of 100 times in bright field and dark field, and no obvious bright spots and scratches are found. The polishing liquid is cleaned, the adhesive is removed, and the indium surface of the polished indium antimonide wafer is corroded with a lactic acid etching liquid. The circular corrosion pit defects on the surface are observed under a differential mode of a microscope with a magnification of 100 times, wherein corrosion pits with a diameter greater than 20 μm are defined as counting pits, and the number of corrosion pits is ≤20 / cm 2 , and obtain an indium antimonide single crystal that meets the technical requirements for preparing infrared detectors.

[0028] (5) The present invention provides a polishing method for effectively reducing corrosion pits on the surface of an InSb2 single crystal wafer. The yield rate of infrared detectors prepared from the InSb2 single crystal wafer polished by the method of the present invention has been greatly improved, which greatly broadens the application of the InSb2 single crystal wafer in infrared detectors. DETAILED DESCRIPTION

[0029] The present invention is described in detail below using specific embodiments, but is not intended to limit the present invention.

[0030] Example 1

[0031] A chemical polishing liquid for effectively reducing corrosion pits on the surface of an indium antimonide single crystal wafer. When preparing the chemical polishing liquid, UP grade phosphoric acid is dissolved in deionized water and stirred evenly to prepare phosphoric acid solutions with mass fractions of 8%, 4% and 2% respectively; hydrogen peroxide is added to the phosphoric acid solution with a mass fraction of 8% under continuous stirring conditions to prepare a rough polishing chemical polishing liquid, wherein the volume ratio of hydrogen peroxide, phosphoric acid and water is 2:1:6, and the pH is 3; hydrogen peroxide is added to the phosphoric acid solution with a mass fraction of 4% under continuous stirring conditions to prepare a first fine polishing chemical polishing liquid, wherein the volume ratio of hydrogen peroxide, phosphoric acid and water is 1:1:6, and the pH is 3; hydrogen peroxide is added to the phosphoric acid solution with a mass fraction of 2% under continuous stirring conditions to prepare a second fine polishing chemical polishing liquid, wherein the volume ratio of hydrogen peroxide, phosphoric acid and water is 0.5:1:6, and the pH is 3.

[0032] During the preparation of the chemical polishing liquid, magnetic stirring is used for stirring, and a temperature control system is used to control the temperature, so that the components in the chemical polishing liquid are fully mixed and uniformly and the temperature is kept constant.

[0033] A polishing method for effectively reducing corrosion pits on the surface of an indium antimonide single crystal wafer, the method steps are as follows:

[0034] (1) Rough polishing

[0035] An 800 μm thick indium antimonide single crystal was bonded to a polishing disc using an adhesive. After being placed for 24 hours, the adhesive was fixed to a rough polishing disc after it was completely solidified. The rough polishing chemical polishing liquid described in this embodiment was used for rough polishing and thinning. The specific conditions were: the rotation speed of the polishing disc was 70 r / min, the pressure was 10 g / cm 2 The dripping rate of the rough polishing chemical polishing liquid is 20 drops / min. The thickness of the single crystal after rough polishing is 660μm. The flatness meets the technical requirements and is transferred to fine polishing.

[0036] (2) First fine polishing

[0037] The indium antimonide single crystal wafer after rough polishing is loaded into a precision polishing machine, and the first fine polishing chemical polishing liquid described in this embodiment is used for the first fine polishing. The specific conditions are: the speed of the polishing disk is 20r / min, the pressure is 5g / cm 2 The drop rate of the chemical polishing liquid for the first fine polishing was 10 drops / min, the polishing time was 3 hours, and an indium antimonide single crystal wafer was obtained after the first fine polishing.

[0038] (3) Second fine polishing

[0039] The indium antimonide single crystal wafer after the first fine polishing is subjected to a second fine polishing using the second fine polishing chemical polishing solution described in this embodiment. The specific conditions are: the rotation speed of the polishing disk is 20r / min, the pressure is 10g / cm2 The dripping rate of the chemical polishing liquid for the second fine polishing is 20 drops / min, the polishing time is 1 hour, and the indium antimonide single crystal wafer after the second fine polishing is obtained, and the polishing is completed.

[0040] The surface of the indium antimonide single crystal wafer prepared in this embodiment was inspected and observed as follows:

[0041] The surface of the polished indium antimonide single crystal wafer was observed under a microscope with a magnification of 100 times in bright field and dark field. No obvious bright spots or scratches were found. The polishing liquid was cleaned and the adhesive was removed. The indium surface of the indium antimonide wafer was corroded with a lactic acid etching liquid. The circular corrosion pit defects on the surface were observed under a microscope with a magnification of 100 times in differential mode. The corrosion pits with a diameter of more than 20 μm were defined as counting pits, and the number of corrosion pits was 18 / cm 2 , an indium antimonide single crystal wafer that meets the technical requirements for preparing infrared detectors is obtained; the yield rate of infrared detectors prepared using the indium antimonide single crystal wafer has made great progress, greatly broadening the application of indium antimonide single crystal wafers in infrared detectors.

[0042] Example 2

[0043] A chemical polishing liquid for effectively reducing corrosion pits on the surface of an indium antimonide single crystal wafer. When preparing the chemical polishing liquid, UP grade phosphoric acid is dissolved in deionized water and stirred evenly to prepare phosphoric acid solutions with mass fractions of 15%, 8% and 4% respectively; hydrogen peroxide is added to the phosphoric acid solution with a mass fraction of 15% under continuous stirring conditions to prepare a rough polishing chemical polishing liquid, wherein the volume ratio of hydrogen peroxide, phosphoric acid and water is 2:1:6, and the pH is 5; hydrogen peroxide is added to the phosphoric acid solution with a mass fraction of 8% under continuous stirring conditions to prepare a first fine polishing chemical polishing liquid, wherein the volume ratio of hydrogen peroxide, phosphoric acid and water is 1:1:6, and the pH is 5; hydrogen peroxide is added to the phosphoric acid solution with a mass fraction of 4% under continuous stirring conditions to prepare a second fine polishing chemical polishing liquid, wherein the volume ratio of hydrogen peroxide, phosphoric acid and water is 0.5:1:6, and the pH is 5.

[0044] During the preparation of the chemical polishing liquid, magnetic stirring is used for stirring, and a temperature control system is used to control the temperature, so that the components in the chemical polishing liquid are fully mixed and uniformly and the temperature is kept constant.

[0045] A polishing method for effectively reducing corrosion pits on the surface of an indium antimonide single crystal wafer, the method steps are as follows:

[0046] (1) Rough polishing

[0047] An 800 μm thick indium antimonide single crystal was bonded to a polishing disc using an adhesive. After being placed for 24 hours, the adhesive was fixed to a rough polishing disc after it was completely solidified. The rough polishing chemical polishing liquid described in this embodiment was used for rough polishing and thinning. The specific conditions were: the rotation speed of the polishing disc was 80 r / min, the pressure was 15 g / cm 2 The dripping rate of the rough polishing chemical polishing liquid is 30 drops / min. The thickness of the single crystal chip after rough polishing is 670μm. The flatness meets the technical requirements and is transferred to fine polishing.

[0048] (2) First fine polishing

[0049] The indium antimonide single crystal wafer after rough polishing is loaded into a precision polishing machine, and the first fine polishing chemical polishing liquid described in this embodiment is used for the first fine polishing. The specific conditions are: the speed of the polishing disk is 25r / min, the pressure is 7g / cm 2 The dripping rate of the chemical polishing liquid for the first fine polishing was 15 drops / min, and the polishing time was 4 hours, and an indium antimonide single crystal wafer was obtained after the first fine polishing.

[0050] (3) Second fine polishing

[0051] The indium antimonide single crystal wafer after the first fine polishing is subjected to a second fine polishing using the second fine polishing chemical polishing solution described in this embodiment. The specific conditions are: the rotation speed of the polishing disk is 30r / min, the pressure is 8g / cm 2 The dripping rate of the chemical polishing liquid for the second fine polishing is 15 drops / min, the polishing time is 2h, and the indium antimonide single crystal wafer after the second fine polishing is obtained, and the polishing is completed.

[0052] The surface of the indium antimonide single crystal wafer prepared in this embodiment was inspected and observed as follows:

[0053] The surface of the polished indium antimonide single crystal wafer was observed under a microscope with a magnification of 100 times in bright field and dark field. No obvious bright spots or scratches were found. The polishing liquid was cleaned and the adhesive was removed. The indium surface of the indium antimonide wafer was corroded with a lactic acid etching liquid. The circular corrosion pit defects on the surface were observed under a microscope with a magnification of 100 times in differential mode. The corrosion pits with a diameter of more than 20 μm were defined as counting pits, and the number of corrosion pits was 15 / cm 2 , an indium antimonide single crystal wafer that meets the technical requirements for preparing infrared detectors is obtained; the yield rate of infrared detectors prepared using the indium antimonide single crystal wafer has made great progress, greatly broadening the application of indium antimonide single crystal wafers in infrared detectors.

[0054] In summary, the above are only preferred embodiments of the present invention and are not intended to limit the protection scope of the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A chemical polishing solution that effectively reduces corrosion pits on the surface of an indium antimonide single wafer, characterized in that: The chemical polishing solution is a mixed solution of hydrogen peroxide, phosphoric acid and water; When used as a rough polishing chemical polishing liquid: the volume ratio of hydrogen peroxide, phosphoric acid and water is 2:1:6, and the pH is 3-5; When used as the first fine polishing chemical polishing liquid: the volume ratio of hydrogen peroxide, phosphoric acid and water is 1:1:6, and the pH is 3-5; When used as the second fine polishing chemical polishing liquid: the volume ratio of hydrogen peroxide, phosphoric acid and water is 0.5:1:6, and the pH is 3-5; The phosphoric acid used in the chemical polishing solution is UP grade phosphoric acid; The water is water with a purity higher than that of deionized water.

2. The chemical polishing solution for effectively reducing corrosion pits on the surface of an indium antimonide single wafer according to claim 1, characterized in that: The water is deionized water or ultrapure water.

3. A chemical polishing solution for effectively reducing corrosion pits on the surface of an indium antimonide single wafer according to claim 1 or 2, characterized in that: When preparing the chemical polishing liquid, phosphoric acid is dissolved in water and stirred evenly to prepare a phosphoric acid solution, and then hydrogen peroxide is added under continuous stirring to prepare the chemical polishing liquid.

4. The chemical polishing solution for effectively reducing corrosion pits on the surface of an InSb single wafer according to claim 3, characterized in that: A rough polishing chemical polishing solution is prepared by adding hydrogen peroxide to a phosphoric acid solution with a mass fraction of 8% to 15% under continuous stirring. The first fine polishing chemical polishing solution is prepared by adding hydrogen peroxide to a phosphoric acid solution with a mass fraction of 4% to 8% under continuous stirring; A second fine polishing chemical polishing liquid is prepared by adding hydrogen peroxide to a phosphoric acid solution with a mass fraction of 2% to 4% under the condition of continuous stirring.

5. The chemical polishing solution for effectively reducing corrosion pits on the surface of an InSb single wafer according to claim 3, characterized in that: During the preparation of the chemical polishing liquid, magnetic stirring is used for stirring, and a temperature control system is used to control the temperature.

6. A polishing method for effectively reducing corrosion pits on the surface of an InSb single crystal wafer, characterized in that: The chemical polishing liquid used in the method is the chemical polishing liquid as claimed in any one of claims 1 to 5, and the steps are as follows: (1) Rough polishing The indium antimonide single crystal wafer with a thickness of 800 μm is bonded and fixed to the rough polishing disc, and rough polishing and thinning are performed using a rough polishing chemical polishing liquid. The thickness of the indium antimonide single crystal wafer after rough polishing is 625 μm to 675 μm, and the flatness meets the technical requirements and then proceeds to fine polishing; (2) First fine polishing The indium antimonide single crystal wafer after rough polishing is loaded into a precision polishing machine, and a first fine polishing chemical polishing liquid is used to perform a first fine polishing to obtain an indium antimonide single crystal wafer after the first fine polishing; (3) Second fine polishing The indium antimonide single crystal wafer after the first fine polishing is subjected to a second fine polishing using a second fine polishing chemical polishing liquid to obtain the indium antimonide single crystal wafer after the second fine polishing, and the polishing is completed.

7. A polishing method for effectively reducing corrosion pits on the surface of an InSb single wafer according to claim 6, characterized in that: In step (1), the specific conditions for rough polishing are: the speed of the polishing disc is 70r / min to 80r / min, the pressure is 10g / cm 2 ~15g / cm 2 , the dripping rate of rough polishing chemical polishing liquid is 20 drops / min~30 drops / min; In step (2), the specific conditions for the first fine polishing are: the speed of the polishing disc is 20r / min to 30r / min, the pressure is 5g / cm 2 ~10g / cm 2 The dripping rate of the first fine polishing chemical polishing liquid is 10 drops / min to 20 drops / min, and the polishing time is 3h to 5h; In step (3), the specific conditions for the second fine polishing are: the speed of the polishing disc is 20r / min to 30r / min, the pressure is 5g / cm 2 ~10g / cm 2 The dripping rate of the second fine polishing chemical polishing liquid is 10 drops / min~20 drops / min, and the polishing time is 1h~2h.