Method for realizing higher line width-diameter depth ratio in wet wafer drying

Abstract

The invention discloses a method for realizing a higher line width-diameter depth ratio in wet wafer drying, and the method comprises the steps: S1, forming a substrate layer, and placing the substrate layer in a to-be-dried wafer groove body in advance; s2, forming a gravitational force layer, and guiding out the water by utilizing the gravitational force formed by the gravitational force difference between controllable agglomerated molecular chains; and S3, forming a protection layer, arranging selected inert gas above the gravity layer, and keeping the stability of the gravity layer. According to the method, the surface tension difference of selected dry water and ultrapure water is utilized, and the dry water has the characteristics of excellent physical insulativity, low boiling point, high vapor pressure, high density and the like which are suitable for semiconductor manufacturing, so that an interface of the ultrapure water (DIW) and the dry water (Perfluor) is formed, and the drying is realized through a Malangoni effect and a capillary effect of the interface; compared with the prior art in which IPA and DIW surface tension difference is adopted for wafer drying treatment, the method has the advantages that the microcosmic drying requirement after circuit line width cleaning with the high width-depth ratio can be met, and the flammable and explosive problems are avoided.

Description

Technical Field

[0001] The invention relates to the technical field of wafer drying, and in particular to a method for achieving a higher line width to diameter ratio in wet wafer drying. Background Art

[0002] Wafer drying is an important step in the semiconductor manufacturing process. Its main purpose is to remove moisture or other liquids from the internal groove structure of the wafer after wet cleaning to prevent water mark compound contamination and improve device quality. The existing technology uses the surface tension difference between IPA and DIW to dry the wafer, but the surface tension difference is small, which makes it difficult to meet the micro-drying requirements after cleaning of circuit lines with a high aspect ratio. In addition, IPA is an organic solvent and has the risk of being flammable and explosive. Summary of the invention

[0003] The object of the present invention is to provide a method for achieving a higher line width to depth ratio in wet wafer drying, so as to solve the problem raised in the above background technology that the prior art uses the surface tension difference between IPA and DIW to dry the wafer, but the surface tension difference is small, which makes it difficult to meet the microscopic drying requirements after cleaning of the circuit line width with a higher aspect ratio, and IPA is an organic solvent and has the risk of being flammable and explosive.

[0004] In order to solve the above technical problems, the present invention is achieved through the following technical solutions: The present invention is a method for achieving a higher line width to depth ratio in wet wafer drying, comprising: S1, forming a base layer and placing it in advance into the wafer tank to be dried; S2, forming a gravitational layer, using the gravitational force formed by the controllable gravitational difference between the agglomerated molecular chains to guide the water out; S3. Form a protective layer, and use the selected inert gas to be arranged above the gravitational layer to maintain the stability of the gravitational layer.

[0005] Furthermore, the specific process steps in S1 are: S11. Select dry water or other liquids with significantly different densities and surface tensions; S12, using pipelines to transport the selected liquid into the wafer tank to be dried, to a water level that can immerse the wafers.

[0006] Furthermore, the specific process steps in S2 are: S21. Select ultrapure water or vaporized water or other media with a lower density than the substrate layer and a significantly different surface tension; S22. When ultrapure water or un-gasified medium with a lower density than the base layer and a significantly different surface tension is selected, the above-mentioned equivalent steps are adopted and the medium is transported through pipelines. When vaporized water or vaporized medium with a lower density than the base layer and a lower surface tension is selected, it can be directly transported using extended pipelines.

[0007] Furthermore, the specific process steps in S3 are: S31, select N2 or CO2 and other inert gases; S32. Use pipelines to transport the selected inert gas to above the gravitational layer.

[0008] Compared with the prior art, the advantages of the present invention are: The present invention forms a safe combination with a large tension difference through other media, including but not limited to the surface tension difference between selected dry water and ultrapure water, and the excellent physical insulation, low boiling point, high vapor pressure, high density and other characteristics of dry water itself suitable for semiconductor manufacturing, to form an interface between ultrapure water (DIW) and dry water (Perfluor), and realizes drying through the Marangoni effect and capillary effect of the interface. Compared with the method of using the surface tension difference between IPA and DIW to dry the wafer in the prior art, the microscopic drying requirement after cleaning of the circuit line width with a higher aspect ratio can be achieved, and the risk of flammability and explosion caused by IPA being an organic solvent is avoided, thereby improving the use effect and meeting the use requirements. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings required for describing the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other accompanying drawings can be obtained based on these accompanying drawings without paying creative work.

[0010] Figure 1 It is a flowchart of the present invention; Figure 2 A flow chart for forming a base layer of the present invention; Figure 3 A flowchart of the gravitational layer formation process of the present invention; Figure 4 A flowchart of the protective layer formation process of the present invention is provided. DETAILED DESCRIPTION

[0011] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the specific embodiments of the present invention are described in detail below with reference to the accompanying drawings.

[0012] In the following description, many specific details are set forth to facilitate a full understanding of the present invention, but the present invention may also be implemented in other ways different from those described herein, and those skilled in the art may make similar generalizations without violating the connotation of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed below.

[0013] In order to make the objectives, technical solutions and advantages of the present invention more clear, the embodiments of the present invention will be further described in detail below with reference to the accompanying drawings.

[0014] See also Figure 1-4 As shown, this embodiment is a method for achieving a higher line width to depth ratio in wet wafer drying, comprising: S1, forming a base layer and placing it in advance into the wafer tank to be dried; The specific process steps are: S11. Select dry water or other liquids with significantly different densities and surface tensions; S12, using pipelines to transport the selected liquid to the wafer tank to be dried; The selected liquid is transferred to the required tank through a pipeline. During this process, the outlet at the lower end of the pipeline is prevented from contacting the wafer, and the distance between the two is adjusted to the minimum to avoid splashing.

[0015] S2, forming a gravitational layer, using the gravitational force formed by the controllable gravitational difference between the agglomerated molecular chains to guide the water out; The specific process steps are: S21. Select ultrapure water or vaporized water or other media with a lower density than the substrate layer and a significantly different surface tension; S22. When ultrapure water or a medium that has not been treated with gasification and has a smaller density than the base layer and a significantly different surface tension is selected, the above equivalent steps are adopted and the medium is transported through a pipeline. When gasified water or a medium that has been treated with gasification and has a smaller density than the base layer and a significantly different surface tension is selected, the medium can be directly transported through an extended pipeline. When ultrapure water or ungasified medium with low density and surface tension relative to the base layer is transported through pipelines, the above steps are used for absorption, and the specific formation principle of the gravitational layer is to utilize vibration under certain conditions, control the modification of the material and size of the hydrate core, change the molecular bonds and morphology to form the gravitational layer, and the formed gravitational layer utilizes the gravitational force formed by the controllable gravitational difference between the agglomerated molecular chains to guide the water out.

[0016] S3, forming a protective layer, using the selected inert gas to be arranged above the gravitational layer to maintain the stability of the gravitational layer; The specific process steps are: S31, select N2 or CO2 and other inert gases; S32, using a pipeline to transport the selected inert gas to above the gravitational layer; Inert gas is placed on the gravitational layer to prevent oxidation of the wafer and high uniformity, and to maintain the stability of the gravitational layer. In the process of using pipelines to transport inert gas, the pressure and temperature inside the pipelines must be guaranteed to avoid gas leakage and reduce the probability of accidents. In the above steps, compared with the original method of using the surface tension difference between IPA and DIW to dry the wafer, this solution uses the surface tension difference between the selected dry water and ultrapure water, as well as the excellent physical insulation, low boiling point, high vapor pressure, high density and other characteristics of dry water itself suitable for semiconductor manufacturing to form an ultrapure water (DIW) and dry water (Perfluor) interface, and achieves drying through the Marangoni effect and capillary effect of the interface. In order to further improve the surface tension difference between the wafer and the multi-media interface (0~180°) under semiconductor-related process conditions, it solves the problem of drying difficulties in the increasingly fine processing of semiconductors, especially in groove and trench structures.

[0017] In the description of the present invention, it is also necessary to explain that, unless otherwise clearly specified and limited, the terms "set", "install", "connect", and "connect" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

Claims

1. A method for achieving a higher line width to depth ratio in wet wafer drying, characterized in that: include: S1, forming a base layer and placing it in advance into the wafer tank to be dried; S2, forming a gravitational layer, using the gravitational force formed by the controllable gravitational difference between the agglomerated molecular chains to guide the water out; S3. Form a protective layer, and use the selected inert gas to be arranged above the gravitational layer to maintain the stability of the gravitational layer.

2. The method for achieving a higher line width to depth ratio in wet wafer drying according to claim 1, characterized in that: The specific process steps in S1 are: S11. Select dry water or other liquids with significantly different densities and surface tensions; S12, using pipelines to absorb the selected liquid and drip it into the wafer tank to be dried.

3. The method for achieving a higher line width to depth ratio in wet wafer drying according to claim 1, characterized in that: The specific process steps in S2 are: S21. Select ultrapure water or vaporized water or other media with a lower density than the substrate layer and a significantly different surface tension; S22. When ultrapure water and un-gasified media with a lower density than the base layer and a significantly different surface tension are selected, the above-mentioned equivalent steps are adopted and the media are transported through pipelines. When vaporized water or vaporized media with a lower density than the base layer and a significantly different surface tension are selected, the extended pipelines can be used directly for transportation.

4. The method for achieving a higher line width to depth ratio in wet wafer drying according to claim 1, characterized in that: The specific process steps in S3 are: S31, select N2 or CO2 and other inert gases; S32. Use pipelines to transport the selected inert gas to above the gravitational layer.

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