Method for Pretreatment Before Measuring Resistance Value of Epitaxial Wafer

Abstract

The pretreatment method for measuring the resistance value of an epitaxial wafer according to the present invention includes a cleaning step (1), a spray drying step (2), a heating and drying step (3), and a static electricity removal step (4). The pretreatment method for measuring the resistance value of an epitaxial wafer according to the present invention replaces the overflow tank with an overflow + quick discharge process, which can ensure that all acid residues or salt residues on the surface of the wafer are cleaned without affecting the measurement effect, and the static electricity removal process can remove static electricity and dangling bonds on the wafer surface to reduce the influence on the resistance value measurement. The resistance uniformity of the epitaxial wafer processed by the pretreatment method for measuring the resistance value of an epitaxial wafer according to the present invention is less than 1.5%, which fully meets the industry requirement of less than 3%.

Description

Technical Field

[0001] The present invention relates to a pretreatment method for measuring the resistance value of an epitaxial wafer.

Background Art

[0002] Before measuring the resistance value, it is necessary to clean the epitaxial wafer. A general cleaning process consists of steps of cleaning, spin-drying, and measurement. The cleaning step includes steps of HF cleaning with a concentration of 25% - 40%, overflow flushing with pure water, treatment with H2O2 at a concentration of 15% - 30% / NH4OH at a concentration of 15% - 30%, overflow flushing with pure water, and treatment with a developer. After the treatment, the resistance value is measured using a measuring instrument. There are major problems with this method. That is, mainly in such a pretreatment, the uniformity of the resistance value fluctuates by 2% - 10% (formula: (max - min) / (max + min) - 1) × 100%). Since the industry generally requires the uniformity of the resistance value to be less than 3%, the existing pretreatment method before measuring the resistance value has relatively low stability.

Summary of the Invention

[0003] One object of the present invention is to overcome the defects in the existing technology and provide a pretreatment method for measuring the measured value of an epitaxial wafer with good stability.

[0004] To achieve the above object, the present invention provides a pretreatment method before measuring the resistance value of an epitaxial wafer, including a cleaning step (1), a spin-drying step (2), a heating and drying step (3), and an electrostatic removal step (4).

[0005] According to one embodiment of the present invention, the above steps (2) and (3) are performed simultaneously, and while spin-drying, heating and drying are performed to remove static electricity.

[0006] According to one embodiment of the present invention, the above heating and drying are performed by heating and drying using nitrogen.

[0007] According to one embodiment of the present invention, the temperature of the above heating and drying is 40 to 60 °C, and the time of heating and drying is 100 to 300 seconds.

[0008] According to one embodiment of the present invention, in the above step (4), for the electrostatic removal treatment, the treatment time for the N-type epitaxial wafer is 400 to 800 seconds, and the treatment time for the P-type epitaxial wafer is 800 to 1500 seconds.

[0009] According to one embodiment of the present invention, when the above epitaxial wafer is an N-type epitaxial wafer, the above cleaning step (1) includes cleaning with HF having a concentration of 25% to 40% at room temperature for 80 to 100 seconds, cleaning with pure water in an overflow tank at room temperature for 60 to 200 seconds, then cleaning with hydrogen peroxide having a concentration of 31% at 75 °C for 400 to 700 seconds, and then cleaning with pure water in the overflow tank at room temperature for 60 to 200 seconds.

[0010] According to one embodiment of the present invention, when the resistivity of the above N-type epitaxial wafer is 1.5 ohm-cm or less, the above step (1) further includes treating with a developer for 90 to 200 seconds.

[0011] According to one embodiment of the present invention, when the above epitaxial wafer is a P-type epitaxial wafer, the above cleaning step (1) includes cleaning with HF having a concentration of 25% to 40% at room temperature for 80 to 100 seconds, and cleaning with pure water in an overflow tank at room temperature for 60 to 200 seconds.

[0012] According to one embodiment of the present invention, when cleaning the above overflow tank with clean water, the clean water in the overflow tank is discharged every 20 to 40 seconds.

[0013] According to one embodiment of the present invention, all the clean water in the overflow tank is discharged within 5 to 15 seconds.

[0014] Before measuring the measured values of the epitaxial wafer according to the present invention, the processing method can ensure that all acid residues or salt residues on the surface of the wafer are washed instead of the overflow tank with the overflow + quick discharge process, which does not affect the measurement effect, and by the process of removing static electricity, the static electricity and dangling bonds on the wafer surface can be removed to reduce the influence on the measurement of the resistance value.

[0015] The uniformity of the resistance value of the epitaxial wafer processed by the pretreatment method for measuring the resistance value of the epitaxial wafer according to the present invention is less than 1.5%, which fully meets the industry requirement of less than 3%.

Embodiments for Carrying Out the Invention

[0016] The following specifically describes the present invention by combining examples and drawings. The pretreatment method for measuring the resistance value of epitaxy includes a cleaning step (1), a spin-drying step (2), a heating and drying step (3), and a static electricity removing step (4).

[0017] According to one embodiment of the present invention, when the above epitaxial wafer is an N-type epitaxial wafer, the above cleaning step (1) uses HF with a concentration of 25% to 40% to clean at room temperature for 80 to 100 seconds, uses pure water in the overflow tank to clean at room temperature for 60 to 200 seconds, and then uses hydrogen peroxide with a concentration of 31% to clean at 70 to 80 °C for 400 to 700 seconds, and then uses pure water to clean in the overflow tank at room temperature for 60 to 200 seconds.

[0018] When the resistivity of the above N-type epitaxial wafer is 1.5 ohm-cm or less, the above step (1) further includes treating with a developer for 90 to 200 seconds.

[0019] According to one embodiment of the present invention, the above step (2) and step (3) are performed simultaneously. While spidrying, heat drying is performed to remove static electricity.

[0020] The above heating and drying are carried out by using nitrogen. The temperature of the above heating and drying is 40 to 60 °C, and the time of heating and drying is 100 to 300 seconds.

[0021] In the above step (4), for the static electricity removal treatment, the treatment time for the N-type epitaxial wafer is 400 to 800 seconds, and the treatment time for the P-type epitaxial wafer is 800 to 1500 seconds.

[0022] According to one embodiment of the present invention, when the above epitaxial wafer is a P-type epitaxial wafer, the above cleaning step (1) includes cleaning with HF at a concentration of 25% to 40% at room temperature for 80 to 100 seconds, and cleaning with pure water in an overflow tank at room temperature for 60 to 200 seconds.

[0023] According to one embodiment of the present invention, when cleaning the above overflow tank with clean water, the clean water in the overflow tank is discharged every 20 to 40 seconds.

[0024] According to one embodiment of the present invention, all the clean water in the above overflow tank is discharged in 5 to 15 seconds.

[0025]

Table 1

[0026] The resistivity of the epitaxy is measured using the method of the present invention, and the results are as follows.

[0027]

Table 2

[0028] Before measuring the measured values of the epitaxial wafer according to the present invention, the processing method is to replace the overflow tank with an overflow + quick discharge process, ensuring that all acid residues or salt residues on the surface of the wafer can be washed, without affecting the measurement effect, and by removing static electricity, the static electricity and dangling bonds on the wafer surface can be removed to reduce the influence on the measurement of the resistance value. The uniformity of the resistance value of the epitaxial wafer processed by the pretreatment method for measuring the resistance value of the epitaxial wafer according to the present invention is less than 1.5%, which fully meets the industry requirement of less than 3%.

[0029] The embodiments according to the present invention are only used for explaining the present invention and do not constitute a limitation of the scope of the claims. All other substantially equivalent substitutions that can be devised by those skilled in the art are included within the protection scope of the present invention. The invention described in the original claims of the present application is appended below. [Appendix 1] A method for treating an epitaxial wafer before measuring its resistance value, comprising a cleaning step (1), a spin-drying step (2), a heating and drying step (3), and an electrostatic removal step (4). [Appendix 2] The above steps (2) and (3) are performed simultaneously, and while spin-drying, heating and drying are performed to remove static electricity. The method for treating an epitaxial wafer before measuring its resistance value according to Appendix 1, characterized in that. [Appendix 3] The above heating and drying are performed by heating and drying using nitrogen. The method for treating an epitaxial wafer before measuring its resistance value according to Appendix 1 or Appendix 2, characterized in that. [Appendix 4] The temperature of the above heating and drying is 40 to 60 °C, and the time for heating and drying is 100 to 300 seconds The method for treating an epitaxial wafer before measuring its resistance value according to Appendix 1 or Appendix 2, characterized in that. [Appendix 5] For the electrostatic removal treatment in the above step (4), the treatment time is 400 to 800 seconds for an N-type epitaxial wafer, and the treatment time is 800 to 1500 seconds for a P-type epitaxial wafer The method for treating an epitaxial wafer before measuring its resistance value according to Appendix 1, characterized in that. [Appendix 6] When the above epitaxial wafer is an N-type epitaxial wafer, the above cleaning step (1) is to clean for 80 to 100 seconds at room temperature using HF with a concentration of 25% to 40%, clean for 60 to 200 seconds at room temperature using pure water in an overflow tank, then clean for 400 to 700 seconds at 75 °C using hydrogen peroxide with a concentration of 31%, and then clean with pure water for 60 to 200 seconds at room temperature in an overflow tank The method for treating an epitaxial wafer before measuring its resistance value according to Appendix 1, characterized in that it includes the above. [Appendix 7] When the resistivity of the above N-type epitaxial wafer is 1.5 ohm-cm or less, the above step (1) further includes treating with a developer for 90 to 200 seconds The method for treating an epitaxial wafer before measuring its resistance value according to Appendix 6, characterized in that it includes the above. [Appendix 8] When the above epitaxial wafer is a P-type epitaxial wafer, the above cleaning step (1) is to clean for 80 to 100 seconds at room temperature using HF with a concentration of 25% to 40%, Wash with pure water in an overflow tank at room temperature for 60 to 200 seconds The method for pre - treatment before measuring the resistance value of the epitaxial wafer according to appended note 1, characterized by including this. [Appended note 9] When washing the above - mentioned overflow tank with clean water Drain the clean water in the overflow tank every 20 to 40 seconds The method for pre - treatment before measuring the resistance value of the epitaxial wafer according to appended note 6 or appended note 8, characterized by this. [Appended note 10] All the clean water in the overflow tank is drained in 5 to 15 seconds The method for pre - treatment before measuring the resistance value of the epitaxial wafer according to appended note 9, characterized by this.

Claims

【Claim 1】 A method for treating an epitaxial wafer before measuring its resistance value, when the above epitaxial wafer is an N-type epitaxial wafer with a resistivity of less than 1.5 ohm-cm, wash with HF at a concentration of 25% to 40% for 80 to 100 seconds at room temperature, wash with pure water in an overflow tank for 60 to 200 seconds at room temperature, drain the above pure water in the above overflow tank every 20 to 40 seconds, and drain the above pure water in the above overflow tank within 5 to 15 seconds, wash with hydrogen peroxide at a concentration of 31% for 400 to 700 seconds at 70 to 80 °C, wash with pure water in an overflow tank for 60 to 200 seconds at room temperature, drain the above pure water in the above overflow tank every 20 to 40 seconds, and drain the above pure water in the above overflow tank within 5 to 15 seconds, a cleaning step (1) of treating with a developer for 90 to 200 seconds, a spin-drying step (2), a drying step (3) by heating with nitrogen where the temperature is 40 to 60 °C and the time is 100 to 300 seconds, an electrostatic removal step (4) where the time for the above epitaxial wafer is 400 to 800 seconds, including, herein, when the above epitaxial wafer is an N-type epitaxial wafer with a resistivity higher than 1.5 ohm-cm, wash with HF at a concentration of 25% to 40% for 80 to 100 seconds at room temperature, wash with pure water in an overflow tank for 60 to 200 seconds at room temperature, drain the above pure water in the above overflow tank every 20 to 40 seconds, and drain the above pure water in the above overflow tank within 5 to 15 seconds, wash with hydrogen peroxide at a concentration of 31% for 400 to 700 seconds at 70 to 80 °C, Wash the overflow tank with pure water at room temperature for 60 to 200 seconds, drain the pure water in the overflow tank every 20 to 40 seconds, and drain the pure water in the overflow tank within 5 to 15 seconds, the washing step (1); The spin-drying step (2); The drying step (3) by heating with nitrogen, where the temperature is 40 to 60 °C and the time is 100 to 300 seconds; The static electricity removal step (4) with a time of 400 to 800 seconds for the above epitaxial wafer; including; Here, when the above epitaxial wafer is a P-type epitaxial wafer, Wash at room temperature for 80 to 100 seconds using HF with a concentration of 25% to 40%, Wash the overflow tank with pure water at room temperature for 60 to 200 seconds, drain the pure water in the overflow tank every 20 to 40 seconds, and drain the pure water in the overflow tank within 5 to 15 seconds, the washing step (1); The spin-drying step (2); The drying step (3) by heating with nitrogen, where the temperature is 40 to 60 °C and the time is 100 to 300 seconds; The static electricity removal step (4) with a time of 800 to 1500 seconds for the above epitaxial wafer; A method for treating an epitaxial wafer before measuring its resistance value, characterized by including the above steps.

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