A wafer cleaning method for effectively controlling edge etching process

Abstract

The application discloses a wafer cleaning method for effectively controlling edge etching process and relates to the technical field of wafer cleaning, and comprises the following steps: S1, controlling the wafer rotation speed to be a first speed, spraying a first chemical liquid on the wafer surface, and controlling the temperature of the three-dimensional direction surface of the wafer, and then removing the first chemical liquid on the wafer surface by using first ultrapure water; S2, controlling the wafer rotation speed to be a second speed, spraying a second chemical liquid on the wafer surface, and then spraying second ultrapure water to remove the second chemical liquid; S3, introducing isopropyl alcohol and nitrogen into the wafer surface to form initial drying of the wafer surface and to form a nanometer film on the wafer surface; and S4, introducing high-temperature isopropyl alcohol into the wafer surface to accumulate isopropyl alcohol on the wafer surface on which the nanometer film of isopropyl alcohol has been formed. In the application, the temperature of the three-dimensional direction surface of the wafer is controlled in the cleaning process, so that the film layer on the wafer surface and the edge region can be effectively removed.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of wafer cleaning, and in particular to a wafer cleaning method for effectively controlling edge etching process. BACKGROUND

[0002] In the process of semiconductor manufacturing, it is usually necessary to clean the surface and edge of the wafer to remove the film layer and impurities on the surface of the wafer, so as to ensure the normal progress of the subsequent process.

[0003] The prior art cleaning method for cleaning the wafer is to provide a cleaning solution to the edge and surface of the wafer, but the cleaning of the film layer on the edge and surface of the wafer is not complete, and residues are easily formed after cleaning, resulting in defects in the semiconductor product. SUMMARY

[0004] The present application aims to provide a wafer cleaning method for effectively controlling edge etching process, which is used to solve the above technical problems.

[0005] The technical solution adopted by the present application is as follows:

[0006] A wafer cleaning method for effectively controlling edge etching process, comprising:

[0007] S1, controlling the rotation speed of the wafer to be a first speed, spraying a first chemical liquid to the surface of the wafer, and controlling the temperature of the three-dimensional surface of the wafer, and then removing the first chemical liquid on the surface of the wafer by using first ultrapure water;

[0008] S2, controlling the rotation speed of the wafer to be a second speed, spraying a second chemical liquid to the surface of the wafer, and then spraying second ultrapure water to remove the second chemical liquid;

[0009] S3, introducing isopropyl alcohol and nitrogen into the surface of the wafer to form a preliminary drying of the surface of the wafer, and forming a nanoscale film on the surface of the wafer;

[0010] S4, introducing high-temperature isopropyl alcohol to the surface of the wafer to accumulate isopropyl alcohol on the surface of the wafer which has formed a nanoscale film of isopropyl alcohol.

[0011] As a preferred, in the S1, the upper surface of the wafer, the lower surface of the wafer and the edge region of the wafer need to be warmed.

[0012] As a preferred, it further comprises a wafer rotating platform, which clamps the wafer on the wafer bearing platform in a non-contact manner.

[0013] As a further preferred, the middle part of the wafer carrying platform is provided with a nitrogen nozzle, and a plurality of inclined jet holes are arranged on the wafer carrying platform at a position of 3 / 4 of the inner diameter area of the wafer relative to the nitrogen nozzle, and the jet holes are inclined from bottom to top to a direction away from the nitrogen nozzle.

[0014] As a further preferred, the upper surface of the wafer carrying platform is provided with a plurality of heating modules, and the plurality of heating modules are arranged in two rings in a ring shape.

[0015] As a preferred, in the S4, isopropanol is accumulated on the wafer surface, and a supercritical fluid is introduced into the wafer surface.

[0016] As a further preferred, the supercritical fluid is carbon dioxide.

[0017] The above technical solution has the following advantages or beneficial effects:

[0018] In the present application, in the process of wafer cleaning, the temperature of the three-dimensional surface of the wafer is controlled, so that the reaction rate of the first chemical liquid with the wafer surface is increased, and through the rotation of the wafer, the hot gas flow on the wafer surface can be converged to the surrounding, so that the hot gas flow can be accumulated at the edge of the wafer, the temperature of the wafer edge can be ensured, the reaction rate of the first chemical liquid at the edge of the wafer is faster, and the film layer on the wafer surface and the edge area can be effectively removed. BRIEF DESCRIPTION OF DRAWINGS

[0019] Figure 1 is a flow chart of the wafer cleaning method for effectively controlling the edge etching process in the present application;

[0020] Figure 2 is a structural schematic diagram of the wafer carrying platform in the present application.

[0021] In the figure: 1, wafer carrying platform; 2, side wall; 3, chamber; 4, wafer; 5, heating module; 6, nitrogen nozzle; 7, jet hole. DETAILED DESCRIPTION

[0022] The technical solutions of the present application will be described clearly and completely below in combination with the drawings. Obviously, the described embodiments are part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor are within the scope of protection of the present application.

[0023] In the description of the present application, it should be noted that, as the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer" and the like appear, the indicated orientation or positional relationship is based on the orientation or positional relationship shown in the drawings, and is only for the convenience of describing the present application and simplifying the description, and does not indicate or imply that the indicated device or element must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation on the present application. In addition, as the terms "first", "second", "third" appear, they are only for descriptive purposes and cannot be understood as indicating or implying relative importance.

[0024] In the description of the present application, it should be noted that, unless otherwise explicitly specified and limited, as the terms "mounting", "connecting", "connecting" appear, they should be understood in a broad sense, for example, they can be fixedly connected, or detachably connected, or integrally connected; can be mechanically connected, or electrically connected; can be directly connected, or indirectly connected through an intermediate medium, or can be connected inside two elements. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0025] Figure 1 is a flow chart of a wafer cleaning method for effectively controlling the edge etching process in the present application; Figure 2 is a structural schematic diagram of a wafer carrying platform in the present application, please refer to Figures 1 to 2 , a preferred embodiment is shown, showing a wafer 4 cleaning method for effectively controlling the edge etching process, comprising:

[0026] S1, control the rotation speed of the wafer 4 to be the first speed, spray the first chemical liquid to the surface of the wafer 4, and control the temperature of the three-dimensional surface of the wafer 4, and then remove the first chemical liquid on the surface of the wafer 4 by the first ultrapure water.

[0027] S2, control the rotation speed of the wafer 4 to be the second speed, spray the second chemical liquid to the surface of the wafer 4, and then spray the second ultrapure water to remove the second chemical liquid.

[0028] S3, pass isopropyl alcohol and nitrogen into the surface of the wafer 4 to form a preliminary drying of the surface of the wafer 4, and form a nanoscale film on the surface of the wafer 4.

[0029] S4, pass high-temperature isopropyl alcohol to the surface of the wafer 4 to accumulate isopropyl alcohol on the surface of the wafer 4 which has formed a nanoscale film of isopropyl alcohol. In this embodiment, as Figure 2As shown, the wafer 4 rotating platform clamps the wafer 4 on the wafer carrying platform 1 in a non-contact manner, a side wall 2 is arranged outside the wafer carrying platform 1, a cavity 3 is formed between the side wall 2 and the wafer carrying platform 1, the surface of the wafer 4 in the three-dimensional direction refers to the upper surface of the wafer 4, the lower surface of the wafer 4 and the surface of the edge region of the wafer 4, and the temperature of the surface of the edge region of the wafer 4 is the highest when heated. When the wafer 4 is cleaned by the first chemical liquid, the three-dimensional temperature control of the wafer 4 can increase the reaction rate of the first chemical liquid with the surface of the wafer 4 and make the reaction more sufficient, so that the cleaning can be realized in a shorter time and the time consumed in the cleaning process can be saved. The surface temperature of the wafer 4 is controlled by the air power assembly to spray hot air flow to the surface of the wafer 4. By controlling the temperature of the hot air flow, the surface of the wafer 4 is kept within a certain temperature range. Since the wafer 4 is always in a rotating state during the process of spraying hot air flow, the hot air flow on the surface of the wafer 4 can be accumulated to the edge region, so that the reaction rate of the first chemical liquid at the edge of the wafer 4 is faster, and the film layer on the surface and the edge region of the wafer 4 can be effectively removed. The first chemical liquid mainly contains hydrofluoric acid and is used for etching and removing the film layer (silicon oxide) on the surface of the wafer 4. The second chemical liquid is a mixture of diluted ammonia, hydrogen peroxide and carbon dioxide. The first chemical liquid and the second chemical liquid are sprayed on the surface of the wafer 4 through nano-level nozzles, and the spraying process is accompanied by 60°-80° micro swing. The spraying of ultrapure water is also carried out by swinging the nano-level nozzles.

[0030] Further, as a preferred embodiment, the middle part of the wafer carrying platform 1 is provided with a nitrogen gas nozzle 6, and a plurality of inclined jet holes 7 are arranged at the position of 3 / 4 of the inner diameter region of the wafer 4 relative to the wafer carrying platform 1, and the jet holes 7 are inclined from bottom to top to the direction away from the nitrogen gas nozzle 6. In this embodiment, the nitrogen gas nozzle 6 is perpendicular to the surface of the central region of the wafer 4, and the sprayed nitrogen gas can dry the lower surface of the wafer 4 and provide an upward force to the wafer 4, so that the wafer 4 is suspended. The jet holes 7 are connected with the external air power assembly and are used to provide hot air flow to the lower surface of the wafer 4. The provided hot air flow needs to be filtered before use. The inclination of the jet holes 7 facilitates the diffusion of the air flow outward and the accumulation of the hot air flow in the edge region of the wafer 4, which can improve the reaction rate and the cleaning effect. The jet holes 7 are arranged in a ring shape.

[0031] Further, as a preferred embodiment, the upper surface of the wafer carrying platform 1 is provided with a plurality of heating modules 5, and the plurality of heating modules 5 are arranged in two rings in a ring shape. In this embodiment, the two rings of heating modules 5 are both located outside the jet holes 7, and the diffused air flow is heated by the heating modules 5 and then diffused outward, which is convenient for maintaining the temperature of the air flow and the temperature in the chamber 3.

[0032] Further, as a preferred embodiment, in S4, after the isopropyl alcohol is accumulated on the surface of the wafer 4, the supercritical fluid is introduced into the surface of the wafer 4.

[0033] Further, as a preferred embodiment, the supercritical fluid is carbon dioxide. In this embodiment, the tension generated by the water molecules and the isopropyl alcohol molecules accumulated on the surface of the wafer 4 can be offset by the tension of the supercritical fluid, so that the tension of the water and isopropyl alcohol molecules can be avoided to cause the pattern collapse phenomenon. The supercritical fluid can be recycled, and the supercritical fluid can be discharged after being controlled to a gas-liquid coexistence state by air pressure and temperature.

[0034] The above description is only a preferred embodiment of the present application, and is not intended to limit the embodiments and protection scope of the present application. Those skilled in the art should be able to realize that any equivalent replacement and obvious changes made according to the content of the present application should be included in the protection scope of the present application.

Claims

1. A wafer cleaning method for effectively controlling the edge etching process, characterized in that, include: S1. Control the wafer rotation speed to a first speed, spray a first chemical solution onto the wafer surface, control the temperature of the wafer surface in three dimensions, and then remove the first chemical solution from the wafer surface using a first ultrapure water. S2. Control the wafer rotation speed to a second speed, spray a second chemical solution onto the wafer surface, and then spray a second ultrapure water to remove the second chemical solution; S3. Isopropanol and nitrogen are introduced into the surface of the wafer to achieve preliminary drying of the wafer surface and form a nanoscale thin film on the wafer surface; S4. High-temperature isopropanol is introduced into the wafer surface to deposit isopropanol on the wafer surface where an isopropanol nano-thin film has been formed. It also includes a wafer rotation platform, which clamps the wafer on the wafer carrier platform in a non-contact manner; The wafer carrier platform has a nitrogen nozzle in the middle, and several inclined jet holes are provided on the wafer carrier platform at a position of 3 / 4 of the inner diameter region of the wafer, and the jet holes are inclined from bottom to top in a direction away from the nitrogen nozzle. The provided jet orifice can be connected to an external aerodynamic assembly to provide hot airflow to the lower surface of the wafer.

2. The wafer cleaning method for effectively controlling the edge etching process as described in claim 1, characterized in that, In step S1, it is necessary to heat the upper surface, the lower surface, and the edge region of the wafer.

3. The wafer cleaning method for effectively controlling the edge etching process as described in claim 1, characterized in that, The upper surface of the wafer carrier platform is provided with several heating modules, which are arranged in two rings.

4. The wafer cleaning method for effectively controlling the edge etching process as described in claim 1, characterized in that, In step S4, after isopropanol is deposited on the wafer surface, a supercritical fluid is introduced into the wafer surface.

5. The wafer cleaning method for effectively controlling the edge etching process as described in claim 4, characterized in that, The supercritical fluid is carbon dioxide.

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