A method for improving the adhesion between photoresist and wafer

Abstract

The present invention provides a method for improving the adhesion between a photoresist and a wafer, comprising the following steps: providing a wafer, forming a carbon dot layer on the surface of the wafer, the carbon dot layer comprising a plurality of carbon dots, all of which are randomly distributed on the surface of the wafer; forming a patterned photoresist layer on the surface of the wafer, the patterned photoresist layer having an opening, the opening exposing a portion of the carbon dot layer, and the patterned photoresist layer outside the opening covering the remaining portion of the carbon dot layer; etching a portion of the thickness of the wafer using the patterned photoresist layer as a mask; and removing the photoresist layer and the carbon dot layer. The present invention forms a good contact surface between the photoresist layer and the wafer by forming a carbon dot layer with randomly distributed carbon dots between the wafer surface and the photoresist layer, thereby improving the adhesion between the photoresist layer and the wafer.

Description

Technical Field

[0001] The invention relates to the field of semiconductor technology, and in particular to a method for improving the adhesion between a photoresist and a wafer. Background Art

[0002] In the semiconductor manufacturing process, photolithography is one of the key technologies of integrated circuits, and it is also an important reason why integrated circuits develop according to Moore's Law. Therefore, without the advancement of photolithography, integrated circuits would not be able to move from the micron era to the nano era.

[0003] In the multi-gate semiconductor process, the photoresist layer located on the gate oxide layer is used as a template for defining the pattern to prevent the acidic solution from corroding the gate oxide layer covered by the photoresist layer during wet etching. However, due to the different properties between the organic properties of the photoresist layer and the inorganic properties on the wafer surface, the compatibility between the two is low, resulting in poor adhesion between the photoresist layer and the gate oxide layer. In this way, at the opening of the pattern defined by the photoresist layer, the acidic solution easily penetrates into the junction of the photoresist layer and the gate oxide layer, causing the gate oxide layer to be corroded. In order to solve the above problems, a surface modifier is usually used to improve the properties of the wafer before forming the photoresist layer, that is, a surface modifier is formed on the gate oxide layer. Among them, HMDS (hexamethyldisilazane) is the most widely used modifier, which can react with the hydroxyl group on the surface of the wafer and adhere to the surface of the gate oxide layer, thereby improving the compatibility between the wafer and the photoresist.

[0004] However, the gate oxide layer formed by the ISSG (high temperature in-situ water vapor method) process has the advantages of few internal defects and smooth surface. However, due to the high process temperature, the surface functional groups of the gate oxide layer are lost in large quantities. At the same time, the surface roughness of the gate oxide layer is low, which can provide fewer active sites for the modifier reaction. Therefore, under advanced processes, the improvement of the compatibility between wafers and photoresists is limited. Summary of the invention

[0005] The purpose of the present invention is to provide a method for improving the adhesion between photoresist and wafer, which can effectively improve the adhesion between photoresist and wafer and prevent acidic solution from penetrating between the photoresist layer and the underlying film layer and corroding the underlying film layer during wet etching.

[0006] In order to solve the above problems, the present invention provides a method for improving the adhesion between a photoresist and a wafer, comprising the following steps:

[0007] Providing a wafer, forming a carbon dot layer on the surface of the wafer, wherein the carbon dot layer includes a plurality of carbon dots, and all the carbon dots are randomly distributed on the surface of the wafer;

[0008] Forming a patterned photoresist layer on the surface of the wafer, wherein the patterned photoresist layer has an opening, wherein the opening exposes a portion of the carbon dot layer, and the patterned photoresist layer outside the opening covers the remaining portion of the carbon dot layer;

[0009] Using the patterned photoresist layer as a mask, etching a portion of the thickness of the wafer;

[0010] The photoresist layer and the carbon dot layer are removed.

[0011] Optionally, all the carbon dots are randomly and discontinuously distributed on the surface of the wafer.

[0012] Optionally, the diameter of each carbon dot is 0.1 nm~100 nm.

[0013] Optionally, the wafer includes a substrate and a film layer to be etched located on the substrate.

[0014] Furthermore, the film layer to be etched is an inorganic material layer.

[0015] Furthermore, the film layer to be etched is a silicon material layer, a silicide layer, an oxide layer or a metal compound layer.

[0016] Furthermore, the film layer to be etched is a silicon oxide layer.

[0017] Furthermore, the specific method of etching the wafer of partial thickness is:

[0018] Using the patterned photoresist layer as a mask, at least a portion of the thickness of the film layer to be etched is wet-etched with an acidic solution, and the carbon dot layer at the opening sinks, so that the opening still exposes the carbon dot layer.

[0019] Furthermore, for the purpose of pattern transfer, the patterned photoresist layer is used as a mask, and the film layer to be etched is wet-etched by an acidic solution, and the carbon dot layer at the opening sinks, so that the opening still exposes the carbon dot layer and the substrate.

[0020] Furthermore, when the purpose is to reduce the thickness of the film layer to be etched, the patterned photoresist layer is used as a mask, and a portion of the thickness of the film layer to be etched is wet-etched with an acidic solution. The carbon dot layer at the opening sinks, so that the opening still exposes the carbon dot layer and the film layer to be etched.

[0021] Compared with the prior art, the present invention has the following unexpected technical effects:

[0022] The present invention provides a method for improving the adhesion between a photoresist and a wafer, comprising the following steps: providing a wafer, forming a carbon dot layer on the surface of the wafer, the carbon dot layer comprising a plurality of carbon dots, all of which are randomly distributed on the surface of the wafer; forming a patterned photoresist layer on the surface of the wafer, the patterned photoresist layer having an opening, the opening exposing a portion of the carbon dot layer, the patterned photoresist layer outside the opening covering the remaining portion of the carbon dot layer; using the patterned photoresist layer as a mask, etching a portion of the thickness of the wafer; removing the photoresist layer and the carbon dot layer. The present invention forms a carbon dot layer with randomly distributed carbon dots between the surface of the wafer and the photoresist layer, so that a good contact surface is formed between the photoresist layer and the wafer, thereby improving the adhesion between the photoresist layer and the wafer, and preventing the acidic solution from penetrating between the photoresist layer and the underlying film layer and corroding the underlying film layer during wet etching. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 A schematic structural diagram of a wafer provided in one embodiment of the present invention.

[0024] Figure 2 FIG. 4 is a schematic diagram of the structure of an embodiment of the present invention after a carbon dot layer is formed.

[0025] Figure 3 It is a schematic diagram of the structure after forming a patterned photoresist layer according to an embodiment of the present invention.

[0026] Figure 4 It is a schematic diagram of the structure after etching the wafer according to an embodiment of the present invention.

[0027] Figure 5 It is a schematic diagram of the structure after removing the photoresist layer and the carbon dot layer according to an embodiment of the present invention.

[0028] Description of reference numerals:

[0029] 100 - wafer; 110 - substrate; 120 - film layer to be etched; 200 - carbon dot layer; 300 - photoresist layer; 310 - opening. DETAILED DESCRIPTION

[0030] A method for improving photoresist and wafer adhesion of the present invention will be described in further detail below. The present invention will be described in more detail below with reference to the accompanying drawings, wherein preferred embodiments of the present invention are shown, and it should be understood that those skilled in the art can modify the present invention described herein and still achieve beneficial effects of the present invention. Therefore, the following description should be understood as being widely known to those skilled in the art, and not as limitation of the present invention.

[0031] For the sake of clarity, not all features of the actual embodiments are described. In the following description, well-known functions and structures are not described in detail because they would clutter the invention with unnecessary detail. It should be recognized that in the development of any actual embodiment, a large number of implementation details must be made to achieve the developer's specific goals, such as changing from one embodiment to another according to the limitations of the relevant system or the relevant business. In addition, it should be recognized that such development work may be complex and time-consuming, but it is just a routine task for those skilled in the art.

[0032] In order to make the purpose and features of the present invention more obvious and easy to understand, the specific implementation methods of the present invention are further described below in conjunction with the accompanying drawings. It should be noted that the accompanying drawings are all in a very simplified form and use inaccurate ratios, which are only used to conveniently and clearly assist in explaining the purpose of the embodiments of the present invention.

[0033] This embodiment provides a method for improving the adhesion between a photoresist and a wafer, comprising the following steps:

[0034] Step S10: providing a wafer, and forming a carbon dot layer on the surface of the wafer, wherein the carbon dot layer includes a plurality of carbon dots, and all the carbon dots are randomly distributed on the surface of the wafer;

[0035] Step S20: forming a patterned photoresist layer on the surface of the wafer, wherein the patterned photoresist layer has an opening, wherein the opening exposes a portion of the carbon dot layer, and the patterned photoresist layer outside the opening covers the remaining portion of the carbon dot layer;

[0036] Step S30: using the patterned photoresist layer as a mask to etch a portion of the thickness of the wafer;

[0037] Step S40: removing the photoresist layer and the carbon dot layer.

[0038] The following combination Figure 1-Figure 5 The method for improving the adhesion between the photoresist and the wafer provided in this embodiment is described in detail.

[0039] See also Figure 1-Figure 2 First, step S10 is performed to provide a wafer 100 and form a carbon dot layer 200 on the surface of the wafer 100. The carbon dot layer 200 includes a plurality of carbon dots, and all the carbon dots are randomly distributed on the surface of the wafer 100.

[0040] Detailed, such as Figure 1 As shown, first, a wafer 100 is provided, and the wafer 100 includes a substrate 110 and a film layer 120 to be etched located on the substrate 110. The film layer 120 to be etched is an inorganic material layer, such as a silicon material layer, a silicide layer (such as a silicon oxide layer, a silicon nitride layer, etc.), an oxide layer (such as a hafnium oxide layer, etc.) or a metal compound layer (such as a titanium nitride layer, etc.).

[0041] In this embodiment, the substrate 110 is a silicon substrate 110 , and the film layer 120 to be etched is a silicon oxide layer. The silicon oxide layer can be formed by an ISSG (high temperature in situ water vapor method) process, or by other methods such as thermal oxidation.

[0042] At the same time, carbon dots (i.e., carbon quantum dots) are synthesized, for example, by a hydrothermal method. Specifically, citric acid is used as a carbon source, a mixed solution of deionized water and ethylene glycol is used as a solvent, and the reaction is carried out under a microwave solvent thermal environment at 180° C. for 10 min to 6 hours to obtain the carbon dots.

[0043] like Figure 2 As shown, then, randomly and discontinuously distributed carbon dots are formed on the surface of the film layer 120 to be etched to form a carbon dot layer 200. The diameter of each carbon dot is 0.1 nm to 100 nm.

[0044] like Figure 3 As shown, step S20 is then performed to form a patterned photoresist layer 300 on the surface of the wafer 100, wherein the patterned photoresist layer 300 has an opening 310, wherein the opening 310 exposes a portion of the carbon dot layer 200, and the patterned photoresist layer 300 outside the opening 310 covers the remaining portion of the carbon dot layer 200.

[0045] In detail, first, a photoresist layer 300 is coated on the surface of the wafer 100, and the photoresist layer 300 covers the carbon dot layer 200 and the surface of the wafer 100. In this embodiment, the photoresist layer 300 is coated on the silicon oxide layer, and the photoresist layer 300 covers the carbon dot layer 200 and the silicon oxide layer. Since the carbon dots have a high specific surface area, and the carbon core surface of the carbon dots contains a large number of oxygen-containing functional groups, such as hydroxyl groups, carboxyl groups, etc., a good contact surface is formed between the photoresist layer 300 and the wafer 100, thereby improving the adhesion between the photoresist layer 300 and the wafer 100.

[0046] Next, the photoresist layer 300 is patterned by photolithography processes such as exposure and development to form a patterned photoresist layer 300, wherein the patterned photoresist layer 300 has an opening 310, wherein the opening 310 exposes a portion of the carbon dot layer 200 and a portion of the film layer 120 to be etched, and the patterned photoresist layer 300 outside the opening 310 covers the remaining portion of the carbon dot layer 200 and a portion of the film layer 120 to be etched. In particular, due to the effect of the carbon dots, the adhesion between the photoresist layer 300 and the wafer 100 in the covered area is maintained well.

[0047] like Figure 4As shown, step S30 is then performed to etch at least a portion of the thickness of the wafer 100 using the patterned photoresist layer 300 as a mask.

[0048] Specifically, using the patterned photoresist layer 300 as a mask, a partial thickness of the wafer 100, i.e., at least a partial thickness of the film layer 120 to be etched, is wet-etched with an acidic solution, and the carbon dot layer 200 at the opening 310 sinks, so that the opening 310 still exposes the carbon dot layer 200.

[0049] In this embodiment, for the purpose of pattern transfer, the patterned photoresist layer 300 is used as a mask, and the film layer 120 to be etched is wet-etched by an acidic solution. The acidic solution does not react with the carbon dots. Therefore, the carbon dot layer 200 at the opening 310 sinks, so that the opening 310 still exposes the carbon dot layer 200 and the substrate 110.

[0050] In another embodiment, when the thickness of the film layer 120 to be etched is reduced, the patterned photoresist layer 300 is used as a mask, and a portion of the thickness of the film layer 120 to be etched is wet-etched by an acidic solution, and the acidic solution does not react with the carbon dots, so the carbon dot layer 200 at the opening 310 sinks, so that the opening 310 still exposes the carbon dot layer 200 and the film layer 120 to be etched. The acidic solution is, for example, a hydrofluoric acid solution.

[0051] In this step, since the acidic solution will not react with the carbon dots, the randomly and discontinuously distributed carbon dot layer 200 has no effect on the etching process; at the same time, due to the random distribution of the carbon dots, the adhesion between the wafer 100 and the photoresist layer 300 is improved, and the acidic solution of the wet etching process is prevented from penetrating into the junction between the wafer 100 and the photoresist, thereby preventing the film layer 120 to be etched from being corroded at the junction.

[0052] like Figure 5 As shown, step S40 is then performed: removing the photoresist layer 300 and the carbon dot layer 200. Specifically, a sulfuric acid and hydrogen peroxide mixed solution is used to remove the photoresist layer 300 and the carbon dot layer 200.

[0053] In summary, the present invention provides a method for improving the adhesion between a photoresist and a wafer, comprising the following steps: providing a wafer, forming a carbon dot layer on the surface of the wafer, the carbon dot layer comprising a plurality of carbon dots, all of which are randomly distributed on the surface of the wafer; forming a patterned photoresist layer on the surface of the wafer, the patterned photoresist layer having an opening, the opening exposing a portion of the carbon dot layer, the patterned photoresist layer outside the opening covering the remaining portion of the carbon dot layer; using the patterned photoresist layer as a mask, etching a portion of the thickness of the wafer; removing the photoresist layer and the carbon dot layer. The present invention forms a carbon dot layer with randomly distributed carbon dots between the surface of the wafer and the photoresist layer, so that a good contact surface is formed between the photoresist layer and the wafer, thereby improving the adhesion between the photoresist layer and the wafer, and preventing the acidic solution from penetrating between the photoresist layer and the underlying film layer and corroding the underlying film layer during wet etching.

[0054] In addition, it should be noted that, unless otherwise specified or indicated, the terms "first" and "second" in the specification are only used to distinguish the various components, elements, steps, etc. in the specification, and are not used to indicate the logical relationship or sequential relationship between the various components, elements, steps, etc.

[0055] It is to be understood that, although the present invention has been disclosed as a preferred embodiment, the above embodiment is not intended to limit the present invention. For any person skilled in the art, without departing from the scope of the technical solution of the present invention, the technical content disclosed above can be used to make many possible changes and modifications to the technical solution of the present invention, or modified into equivalent embodiments of equivalent changes. Therefore, any simple modification, equivalent change and modification made to the above embodiments according to the technical essence of the present invention without departing from the content of the technical solution of the present invention still falls within the scope of protection of the technical solution of the present invention.

Claims

1. A method for improving the adhesion between a photoresist and a wafer, characterized in that: The following steps are involved: A wafer is provided, and a carbon dot layer is formed on the surface of the wafer, wherein the carbon dot layer includes a plurality of carbon dots, and all the carbon dots are randomly distributed on the surface of the wafer, so that a good contact surface is formed between the photoresist layer and the wafer; Forming a patterned photoresist layer on the surface of the wafer, wherein the patterned photoresist layer has an opening, wherein the opening exposes a portion of the carbon dot layer, and the patterned photoresist layer outside the opening covers the remaining portion of the carbon dot layer; Using the patterned photoresist layer as a mask, etching a portion of the wafer thickness, the carbon dot layer at the opening sinks, so that the opening still exposes the carbon dot layer; The photoresist layer and the carbon dot layer are removed using a sulfuric acid and hydrogen peroxide mixed solution.

2. The method for improving the adhesion between a photoresist and a wafer as claimed in claim 1, characterized in that: All the carbon dots are randomly and discontinuously distributed on the surface of the wafer.

3. The method for improving the adhesion between a photoresist and a wafer as claimed in claim 1, characterized in that: The diameter of each carbon dot is 0.1 nm to 100 nm.

4. The method for improving the adhesion between a photoresist and a wafer as claimed in claim 1, characterized in that: The wafer comprises a substrate and a film layer to be etched located on the substrate.

5. The method for improving the adhesion between a photoresist and a wafer as claimed in claim 4, characterized in that: The film layer to be etched is an inorganic material layer.

6. The method for improving the adhesion between a photoresist and a wafer as claimed in claim 5, characterized in that: The film layer to be etched is a silicon material layer, a silicide layer, an oxide layer or a metal compound layer.

7. The method for improving the adhesion between a photoresist and a wafer as claimed in claim 6, characterized in that: The film layer to be etched is a silicon oxide layer.

8. The method for improving the adhesion between a photoresist and a wafer as claimed in claim 4, characterized in that: The specific method of etching the wafer of partial thickness is: Using the patterned photoresist layer as a mask, at least a portion of the thickness of the film layer to be etched is wet-etched with an acidic solution, and the carbon dot layer at the opening sinks, so that the opening still exposes the carbon dot layer.

9. The method for improving the adhesion between a photoresist and a wafer as claimed in claim 8, characterized in that: When the purpose is pattern transfer, the patterned photoresist layer is used as a mask to wet-etch the film layer to be etched by an acidic solution, and the carbon dot layer at the opening sinks, so that the opening still exposes the carbon dot layer and the substrate.

10. The method for improving the adhesion between photoresist and wafer according to claim 8, characterized in that: When the purpose is to reduce the thickness of the film layer to be etched, the patterned photoresist layer is used as a mask, and a portion of the thickness of the film layer to be etched is wet-etched with an acidic solution. The carbon dot layer at the opening sinks, so that the opening still exposes the carbon dot layer and the film layer to be etched.

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