Method for detecting reference surface of crystal orientation silicon single crystal rod

Abstract

The invention provides a detection result; 111gt, 111gt; the invention discloses a crystal orientation monocrystalline silicon rod reference surface detection method, and belongs to the technical field of monocrystalline silicon reference surface detection. 111gt, 111gt; the method comprises the following steps: processing a reference surface on a crystal orientation silicon single crystal rod, cutting an initial sample wafer with a certain thickness from the end surface, and marking the cutting surface of the initial sample wafer as a surface to be detected; immersing the initial sample wafer into the mixed liquid medicine for surface anisotropic corrosion to obtain a treated sample wafer; soaking the treated sample in hot water at a certain temperature for a first preset time, and removing the residual liquid medicine to obtain a sample to be detected; finally, in a dark environment, the to-be-detected surface of the to-be-detected sample wafer is opposite to the background wall, the reference surface of the to-be-detected sample wafer is vertically located on the right side, then a laser pen is used for irradiating the to-be-detected surface of the to-be-detected sample wafer so as to judge the reference surface through the projection pattern of the background wall, and if the projection presents a Y-shaped pattern, the result is judged; 111gt, 111gt; the reference plane of the crystal orientation silicon single crystal rod is lt; 1 to 10 gt; if the projection presents an inverted Y-shaped pattern, judging the result; 111gt, 111gt; the reference plane of the crystal orientation silicon single crystal rod is lt; -110 gt,-110 gt; .

Description

Technical Field

[0001] This invention relates to the field of single-crystal silicon reference plane detection technology, and particularly to a detection method. <111> Method for oriented reference plane of single-crystal silicon rod. Background Technology

[0002] In the manufacturing of single-crystal silicon semiconductors, the master reference plane is the core benchmark for ingot processing, directly determining the crystal orientation consistency and electrical properties of the silicon wafer, especially for Czochralski-grown wafers. <111> After tumbling, monocrystalline silicon rods typically use either <1-10> or <-110> as the primary reference plane. However, the resistivity of silicon wafers processed using these two reference planes is drastically different: wafers processed using the <1-10> reference plane have an electron mobility greater than 1400 cm² / V·s (resistance value acceptable); wafers processed using the <-110> reference plane have an electron mobility of only 840 cm² / V·s (resistance value failure risk greater than 55%, unacceptable). Therefore, it is necessary to strictly distinguish between these two reference planes to avoid errors in the processing of the reference plane, which could lead to defective silicon wafers entering the customer's market. However, when using existing X-ray inspection methods to examine the reference planes of monocrystalline silicon rods, the orientations of both the <1-10> and <-110> reference planes are 23°23′ under X-ray diffraction, making it impossible to distinguish between them using X-ray inspection. Summary of the Invention

[0003] In view of this, and to address the above shortcomings, it is necessary to propose a detection method. <111> Methods for referencing the crystal orientation of a single-crystal silicon rod to avoid <111> Errors occurred during the processing of the <1-10> and <-110> reference planes of the crystal orientation monocrystalline silicon rod, resulting in defective silicon wafers being delivered to customers.

[0004] This invention provides a detection <111> The method for determining the reference plane of a single-crystal silicon rod includes the following steps: Step 1: <111> After a reference surface is fabricated from a crystal-oriented single-crystal silicon rod, an initial sample of a certain thickness is cut from its end face, and the cut surface of the initial sample is marked as the surface to be tested. Step 2: Immerse the initial sample in the mixed solution for anisotropic surface etching to obtain the treated sample; Step 3: Immerse the treated sample in hot water at a certain temperature for a first predetermined time to remove residual drug solution, and then obtain the sample to be tested; Step 4: In a dark environment, the test surface of the sample is directly opposite the background wall, and the reference surface of the sample is vertically located on the right side. Then, a laser pointer is used to illuminate the test surface of the sample to determine the reference surface through the projection pattern on the background wall. If the projection presents an equilateral Y-shaped pattern, then the sample is determined to be the reference surface. <111> The reference plane for the crystal-oriented single-crystal silicon rod is <1-10>. If the projection presents an inverted Y-shaped pattern, then it is determined that... <111> The reference plane for the crystal orientation of the single-crystal silicon rod is <-110>.

[0005] Preferably, the thickness of the initial sample in step 1 is 700µm-800µm.

[0006] Preferably, step 2 specifically involves immersing the initial sample in the mixed medicinal solution at a certain temperature and then ultrasonically cleaning it for a second predetermined time to obtain the treated sample.

[0007] Preferably, the temperature of the mixed solution is 22℃-28℃, and the second predetermined time is 8min-12min.

[0008] Preferably, the mixed solution is a mixture of sodium hydroxide solution and surfactant.

[0009] Preferably, the volume ratio of the sodium hydroxide solution to the surfactant is 25900-26100 ml: 30-50 ml.

[0010] Preferably, the ratio of sodium hydroxide to water in the sodium hydroxide solution is 3850g-3950g: 22050ml-22150ml.

[0011] Preferably, in step 3, the temperature of the hot water is 70℃-90℃, and the first predetermined time is 9min-11min.

[0012] Preferably, after step 3, a rewashing step is also included, which specifically involves rinsing the sample to be tested in an overflow tank filled with deionized water for 9-11 minutes.

[0013] Preferably, in step 4, the center point of the test surface of the sample is illuminated with the laser pointer.

[0014] As can be seen from the above technical solution, the present invention provides a detection method. <111> The method of using a reference plane for a single-crystal silicon rod with crystal orientation firstly <111> After a reference surface is fabricated from a crystal-oriented single-crystal silicon rod, an initial sample of a certain thickness is cut from its end face, and the cut surface of the initial sample is marked as the test surface. Next, the initial sample is immersed in a mixed chemical solution for anisotropic surface etching to obtain a processed sample. Then, the processed sample is immersed in hot water at a certain temperature for a first predetermined time to remove residual chemical solution, resulting in the sample to be tested. Finally, in a dark environment, the test surface of the sample is directly opposite the background wall, and the reference surface of the sample is vertically positioned on the right. A laser pointer is then used to illuminate the test surface of the sample to determine the reference surface through the projection pattern on the background wall. If the projection presents an equilateral Y-shaped pattern, then the reference surface is determined. <111> The reference plane for the crystal orientation of the single-crystal silicon rod is <1-10>. If the projection presents an inverted Y-shaped pattern, then it is determined that... <111> The reference plane for the crystal orientation of the single crystal silicon rod is <-110>, in order to avoid errors in processing the <1-10> reference plane and the <-110> reference plane, which would result in defective silicon wafers entering the customer's market. Compared with the prior art, the advantages of this invention are: This invention uses a mixed solution to perform anisotropic etching on the surface of a silicon wafer, amplifying its microstructural differences, and then uses optical path projection to transform these structural differences into macroscopic patterns, thereby achieving… <111> The determination of the reference plane of a single-crystal silicon rod involves the following steps: After the initial sample is etched with a mixed solution, three symmetrically distributed microstep structures will form on its surface. When irradiated by a laser, these three symmetrically distributed microstep structures will form a reflective phase grating, causing optical path interference. This will then cause the reflected light to superimpose on the background wall to form a Y-shaped interference pattern. The staff will hold the sample to be tested so that the test surface of the sample is directly opposite the background wall and the reference plane of the sample is vertically located on the right side to determine the coordinate reference. Since the crystal symmetry of the <1-10> and <-110> reference planes is a mirror image, the projection will show an upright Y-shaped pattern and an inverted Y-shaped pattern respectively. Attached Figure Description

[0015] Figure 1 The detection provided by the present invention <111> A flowchart of the method for oriented reference plane of a single-crystal silicon rod.

[0016] Figure 2 This is a schematic diagram of a Y-shaped pattern.

[0017] Figure 3 This is a schematic diagram of an inverted Y-shaped pattern.

[0018] Figure 4 This is a projection image of the sample 1 to be tested in Example 1, which is irradiated by laser.

[0019] Figure 5 This is a projection of the initial sample 3 in Comparative Example 1 illuminated by laser.

[0020] Figure 6 This is a projection image of the processed sample 4 in Comparative Example 2, which is irradiated by laser. Detailed Implementation

[0021] To further understand the present invention, preferred embodiments of the present invention are described below in conjunction with examples. However, it should be understood that these descriptions are only for further illustrating the features and advantages of the present invention, and not for limiting the scope of the claims of the present invention.

[0022] Please refer to Figures 1 to 3 The present invention provides a detection <111> The method for determining the reference plane of a single-crystal silicon rod includes the following steps: Step 1: <111> After a reference surface is fabricated from a crystal-oriented single-crystal silicon rod, an initial sample of a certain thickness is cut from its end face, and the cut surface of the initial sample is marked as the surface to be tested. Step 2: Immerse the initial sample in the mixed solution for anisotropic surface etching to obtain the treated sample; Step 3: Immerse the treated sample in hot water at a certain temperature for a first predetermined time to remove residual drug solution, and then obtain the sample to be tested; Step 4: In a dark environment, the test surface of the sample is directly opposite the background wall, and the reference surface of the sample is vertically located on the right side. Then, a laser pointer is used to illuminate the test surface of the sample to determine the reference surface through the projection pattern on the background wall. If the projection presents an equilateral Y-shaped pattern, then the sample is determined to be the reference surface. <111> The reference plane for the crystal-oriented single-crystal silicon rod is <1-10>. If the projection presents an inverted Y-shaped pattern, then it is determined that... <111> The reference plane for the crystal orientation of the single-crystal silicon rod is <-110>.

[0023] Compared with the prior art, the advantages of this invention are: This invention uses a mixed solution to perform anisotropic etching on the surface of a silicon wafer, amplifying its microstructural differences, and then uses optical path projection to transform these structural differences into macroscopic patterns, thereby achieving… <111> The determination of the reference plane for a single-crystal silicon rod involves the following steps: After etching with a mixed solution, the initial sample forms three symmetrically distributed micro-step structures on its surface. When irradiated by a laser, these three symmetrically distributed micro-step structures form a reflective phase grating, inducing optical path interference. This causes the reflected light to superimpose on the background wall, forming a Y-shaped interference pattern. The operator holds the sample to be tested, ensuring the test surface is directly opposite the background wall and the reference plane is vertically positioned on the right side to determine the coordinate reference. Because the crystal symmetry of the <1-10> and <-110> reference planes is mirror-image, the projection will show corresponding upright and inverted Y-shaped patterns, respectively. This avoids... <111> Errors occurred during the processing of the <1-10> and <-110> reference planes of the crystal orientation monocrystalline silicon rod, resulting in defective silicon wafers being delivered to customers.

[0024] Furthermore, to avoid the initial sample being too thin, causing excessive corrosion of the mixed solution and resulting in silicon wafer breakage, or too thick, affecting laser transmission, the thickness of the initial sample in step 1 is 700µm-800µm.

[0025] Furthermore, step 2 specifically involves immersing the initial sample in the mixed solution at a certain temperature and ultrasonically cleaning it for a second predetermined time to obtain the treated sample. Ultrasonic vibration causes convection in the mixed solution, ensuring that the reactive ions in the mixed solution can flow evenly to the surface of the initial sample and removing the byproducts generated by corrosion in a timely manner.

[0026] Specifically, the temperature of the mixed solution is 22℃-28℃, and the second predetermined time is 8min-12min.

[0027] Furthermore, the mixed solution is a mixture of sodium hydroxide solution and surfactant, wherein the surfactant is EC-1 cleaning agent. The synergistic effect of sodium hydroxide solution and EC-1 cleaning agent is that EC-1 cleaning agent removes grease from the surface of the initial sample, reducing surface tension, thereby promoting uniform penetration of sodium hydroxide solution into the surface of the initial sample for corrosion, ensuring uniform surface corrosion.

[0028] Specifically, the volume ratio of the sodium hydroxide solution to the surfactant is 25900-26100 ml: 30-50 ml.

[0029] Specifically, the ratio of sodium hydroxide to water in the sodium hydroxide solution is 3850g-3950g: 22050ml-22150ml.

[0030] Furthermore, in order to prevent residual sodium hydroxide crystals on the surface of the treated sample from causing diffuse reflection noise during laser irradiation, in step 3, the temperature of the hot water is 70℃-90℃, and the first predetermined time is 9min-11min. The residual sodium hydroxide crystals on the surface of the treated sample are removed by the high-temperature diffusion of the hot water, thus eliminating diffuse reflection noise.

[0031] Furthermore, after step 3 is completed, a rewashing step is also included. The rewashing step specifically involves rinsing the sample to be tested in an overflow tank filled with deionized water for 9-11 minutes.

[0032] Furthermore, in step 4, the center point of the test surface of the sample is illuminated with the laser pointer.

[0033] The following embodiments and comparative examples of the method of the present invention further illustrate the technical solution and technical effects of the present invention. It should be noted that the following experimental examples are only for further explanation of the present invention and do not limit the technical solution of the present invention.

[0034] Example 1: No. 1 <111> After processing a reference surface into a crystal-oriented single-crystal silicon rod, a 700µm thick silicon wafer is cut from its end face as initial sample 1. The cut surface of initial sample 1 is marked as the test surface. Then, initial sample 1 is immersed in a mixed chemical solution at 25℃ and ultrasonically cleaned for 10 minutes to obtain processed sample 1. The mixed chemical solution consists of 26000ml of sodium hydroxide solution and 40ml of EC-1 cleaning agent, with a sodium hydroxide to pure water ratio of 3900ml:22100ml. Subsequently, processed sample 1 is immersed in 80℃ hot water for 10 minutes to remove residual chemical solution, resulting in sample 1 to be tested. Sample 1 to be tested is then rinsed in an overflow tank filled with deionized water for 10 minutes and removed. In a dark environment, the operator holds sample 1 with the test surface directly opposite the background wall and the reference surface vertically positioned on the right. A laser pointer is used to illuminate the center point of the test surface of sample 1. Figure 4 The projection shown presents a Y-shaped pattern, proving that No. 1 <111> The reference plane processed from the crystal-oriented single-crystal silicon rod is <1-10>.

[0035] Example 2: No. 2 <111> After processing a reference surface into a crystal-oriented single-crystal silicon rod, a 700µm thick silicon wafer is cut from its end face as initial sample 2. The cut surface of initial sample 2 is marked as the test surface. Then, initial sample 2 is immersed in a mixed chemical solution at 25℃ and ultrasonically cleaned for 10 minutes to obtain processed sample 2. The mixed chemical solution consists of 26000ml of sodium hydroxide solution and 40ml of EC-1 cleaning agent, with a sodium hydroxide to pure water ratio of 3900ml:22100ml. Subsequently, processed sample 2 is immersed in 80℃ hot water for 10 minutes to remove residual chemical solution, resulting in sample 2 to be tested. Sample 2 to be tested is then rinsed in an overflow tank filled with deionized water for 10 minutes and removed. In a dark environment, the operator holds sample 2 with the test surface directly opposite the background wall and the reference surface vertically positioned on the right. A laser pointer is used to illuminate the center point of the test surface of sample 2. Figure 3 The projection shown presents an inverted Y-shaped pattern, proving that No. 2 <111> The reference plane processed from the crystal-oriented single-crystal silicon rod is <-110>.

[0036] Comparative Example 1: Example 1 has proven that No. 1 <111> After the reference plane <1-10> is processed from the crystal-oriented single-crystal silicon rod, it is again at plane 1. <111> A 700µm thick silicon wafer was cut from the end face of a single-crystal silicon rod as initial sample 3. The cut surface of initial sample 3 was marked as the test surface. In a dark environment, the operator held initial sample 3 with the test surface directly opposite the background wall and the reference surface of initial sample 3 vertically positioned on the right. A laser pointer was used to illuminate the center point of the test surface of initial sample 3. Figure 5 As shown, its projection presents a disordered scattered light spot.

[0037] Comparative Example 2: Example 1 has proven that No. 1 <111> After the reference plane <1-10> is processed from the crystal-oriented single-crystal silicon rod, it is again at plane 1. <111> A 700µm thick silicon wafer was cut from the end face of a single-crystal silicon rod as the initial sample 4, and the cut surface of the initial sample 4 was marked as the test surface. The initial sample 4 was then immersed in a mixed cleaning solution at 25°C and ultrasonically cleaned for 10 minutes to obtain the processed sample 4. The mixed cleaning solution consisted of 26000ml of sodium hydroxide solution and 40ml of EC-1 cleaning agent, with a sodium hydroxide to pure water ratio of 3900ml:22100ml. In a dark environment, the operator held the processed sample 4, ensuring that the test surface of the processed sample 4 was directly opposite the background wall and the reference surface of the processed sample 4 was vertically positioned on the right. A laser pointer was used to illuminate the center point of the test surface of the processed sample 4. Figure 6 As shown, its projection presents a disordered scattered light spot.

[0038] Therefore, in Example 1, starting from number 1 <111> After the initial sample 1, cut from a single-crystal silicon rod, undergoes anisotropic etching and cleaning using a mixed solution, and is then illuminated with a laser pointer in a dark environment at the center point of the surface to be tested, a Y-shaped pattern is projected, proving that sample 1... <111> The reference planes processed from the crystal-oriented single-crystal silicon rods are <1-10>, starting from plane 2 in Example 2. <111> The initial sample 2, cut from a single-crystal silicon rod, was anisotropically etched and cleaned using a mixed solution. In a dark environment, a laser pointer was used to illuminate the center point of the surface to be tested on sample 2. The projected image displayed an inverted Y-shaped pattern, proving that sample 2... <111> The reference plane processed from the crystal-oriented single-crystal silicon rod is <-110>. In Comparative Example 1, the reference plane is known from Example 1. <111> After the reference plane <1-10> is processed from the crystal-oriented single-crystal silicon rod, it is again at plane 1. <111> The initial sample 3, cut from a single-crystal silicon rod, was not etched with a mixed solution. When the center point of the test surface of the initial sample 3 was directly illuminated with a laser pointer in a dark environment, the projection showed disordered scattered light spots, making it impossible for the staff to determine sample number 1 based on the projected pattern. <111> The reference plane for the crystal orientation of the single-crystal silicon rod is <1-10>. In Comparative Example 2, the reference plane is 1, as known from Example 1. <111> After the reference plane <1-10> is processed from the crystal-oriented single-crystal silicon rod, it is again at plane 1. <111> The initial sample 4, cut from a single-crystal silicon rod, was etched with a mixed solution but not cleaned. When the center point of the surface to be tested on sample 4 was illuminated with a laser pointer in a dark environment, the projected image showed disordered scattered light spots, making it impossible for the staff to identify sample 1 based on the projected pattern. <111> The reference plane for the crystal orientation of the single-crystal silicon rod is <1-10>.

[0039] The above-disclosed embodiments are merely preferred embodiments of the present invention and should not be construed as limiting the scope of the invention. Those skilled in the art will understand that implementing all or part of the above-described embodiments and making equivalent changes in accordance with the claims of the present invention are still within the scope of the invention.

Claims

1. A detection method <111> The method for oriented reference planes of single-crystal silicon rods is characterized by, Includes the following steps: Step 1: <111> After a reference surface is fabricated from a crystal-oriented single-crystal silicon rod, an initial sample of a certain thickness is cut from its end face, and the cut surface of the initial sample is marked as the surface to be tested. Step 2: Immerse the initial sample in the mixed solution for anisotropic surface etching to obtain the treated sample; Step 3: Immerse the treated sample in hot water at a certain temperature for a first predetermined time to remove residual drug solution, and then obtain the sample to be tested; Step 4: In a dark environment, the test surface of the sample is directly opposite the background wall, and the reference surface of the sample is vertically located on the right side. Then, a laser pointer is used to illuminate the test surface of the sample to determine the reference surface through the projection pattern on the background wall. If the projection presents an equilateral Y-shaped pattern, then the sample is determined to be the reference surface. <111> The reference plane for the crystal-oriented single-crystal silicon rod is <1-10>. If the projection presents an inverted Y-shaped pattern, then it is determined that... <111> The reference plane for the crystal orientation of the single-crystal silicon rod is <-110>.

2. The detection method according to claim 1 <111> The method for oriented reference planes of single-crystal silicon rods is characterized by: The thickness of the initial sample in step 1 is 700µm-800µm.

3. The detection method according to claim 1 or 2 <111> The method for oriented reference planes of single-crystal silicon rods is characterized by: Step 2 specifically involves immersing the initial sample in the mixed drug solution at a certain temperature and then ultrasonically cleaning it for a second predetermined time to obtain the processed sample.

4. The detection method according to claim 3 <111> The method for oriented reference planes of single-crystal silicon rods is characterized by: The temperature of the mixed solution is 22℃-28℃, and the second predetermined time is 8min-12min.

5. The detection method according to claim 3 <111> The method for oriented reference planes of single-crystal silicon rods is characterized by: The mixed solution is a mixture of sodium hydroxide solution and surfactant.

6. The detection method according to claim 4 <111> The method for oriented reference planes of single-crystal silicon rods is characterized by: The volume ratio of the sodium hydroxide solution to the surfactant is 25900-26100 ml: 30-50 ml.

7. The detection method according to claim 5 <111> The method for oriented reference planes of single-crystal silicon rods is characterized by: The ratio of sodium hydroxide to water in the sodium hydroxide solution is 3850g-3950g: 22050ml-22150ml.

8. The detection method according to claim 1 <111> The method for oriented reference planes of single-crystal silicon rods is characterized by: In step 3, the temperature of the hot water is 70℃-90℃, and the first predetermined time is 9min-11min.

9. The detection method according to claim 1 <111> The method for oriented reference planes of single-crystal silicon rods is characterized by: After step 3 is completed, a rewashing step is also included. The rewashing step is specifically: the sample to be tested is placed in an overflow tank filled with deionized water and rinsed for 9-11 minutes.

10. The detection method according to claim 1 <111> The method for oriented reference planes of single-crystal silicon rods is characterized by: In step 4, the laser pointer is used to illuminate the center point of the surface to be tested on the sample.

Images