A method for improving the uniformity of metal layer peeling pattern

Abstract

The present application discloses a method for improving the uniformity of metal layer stripping patterns, which relates to the field of semiconductor technology, including: coating a positive photoresist on the surface of a silicon wafer with a patterned layout; selecting a desired patterned mask plate to expose the photoresist in the intended exposure area; using a developer to pattern the exposed photoresist to dissolve the photoresist above the corresponding pattern and retain the photoresist in other positions as a mask for metal layer deposition; depositing a metal layer of a specified thickness on the patterned silicon wafer surface; taking out the silicon wafer after metal deposition and performing preliminary infiltration; after infiltration, attaching an adhesive film to the surface of the metal layer; uncovering the adhesive film in a set direction to separate the metal layer and the photoresist adhered to the photoresist; and removing the photoresist. The method of the present application optimizes the metal layer stripping process, reduces the side wall residue of the metal pattern after stripping, and improves the uniformity of the metal pattern.

Description

Technical Field

[0001] The present application relates to the field of semiconductor technology, and in particular to a method for improving the uniformity of metal layer peeling patterns. Background Art

[0002] As the integration of micro-electromechanical systems (MEMS) and integrated circuits becomes increasingly higher, semiconductor optoelectronic devices continue to develop in the direction of miniaturization, which places higher requirements on the stripping process based on photolithography.

[0003] Photolithography is one of the key processes for processing and manufacturing micro-nano-sized graphics and devices. The principle of the process is that after the photoresist in a specific area is exposed to high-energy ultraviolet light, a photochemical reaction occurs, causing the photoresist to be selectively corroded in the area during the development process, thereby obtaining a patterned photoresist mask.

[0004] The stripping process is a method of obtaining a patterned metal layer by dissolving the photoresist, removing the photoresist film and the metal on the film at the same time, and retaining the metal deposited on the substrate. Compared with wet etching and dry etching processes for patterning metal layers, the stripping process has the advantages of high resolution and no damage, and is widely used in the production and manufacturing of MEMS and integrated circuits. Figure 2 As shown in the figure, during the stripping process, the light energy received by the photoresist from top to bottom during exposure gradually decreases, and the development speed gradually slows down from top to bottom, resulting in a photoresist sidewall that is narrow at the top and wide at the bottom. Therefore, when the metal layer is deposited, metal particles will adhere to the sidewall of the pattern, blocking the contact between the photoresist and the stripping agent, resulting in the metal layer on the surface of the photoresist being unable to be completely removed, and the metal pattern sidewall residue phenomenon is serious, which reduces the morphological uniformity of the stripping pattern and affects the performance of the device using the stripping process as the electrode patterning method.

[0005] Patent CN201810162652.3 (CN108389784A) improves the stripping effect by using a double-layer glue technology in which the development speed of the bottom glue is greater than the development speed of the photoresist after exposure. Patent CN202210819190.4 (CN115172162A) removes the negative photoresist by ultrasonic wet method to achieve the stripping of the metal film layer. However, the above inventions cannot avoid the problem of low resolution of negative glue and high requirements for equipment and process for multi-layer mask stripping. Summary of the invention

[0006] The embodiment of the present application provides a method for improving the uniformity of metal layer stripping patterns, which is used to optimize the thick metal layer stripping process, reduce the side wall residue of the metal pattern after stripping, improve the uniformity of the metal pattern, and improve the performance of devices using the stripping process as an electrode patterning method.

[0007] The present application provides a method for improving the uniformity of metal layer peeling patterns, including:

[0008] Coating positive photoresist on the surface of the silicon wafer on which the patterning is completed;

[0009] Selecting a desired patterned mask to expose the photoresist in the area to be exposed;

[0010] The exposed photoresist is patterned using a developer to dissolve the photoresist above the corresponding pattern and retain the photoresist at other positions as a mask for metal layer deposition;

[0011] Depositing a metal layer of a specified thickness on the surface of the patterned silicon wafer;

[0012] Take out the silicon wafer after metal deposition and perform preliminary wetting;

[0013] After infiltration, an adhesive film is attached to the surface of the metal layer;

[0014] The adhesive film is peeled off according to the set direction to separate the metal layer adhered to the photoresist from the photoresist;

[0015] Remove the photoresist and you're done.

[0016] Optionally, the thickness uniformity of the positive photoresist coated on the surface of the silicon wafer is required to be less than 5%.

[0017] Optionally, depositing a metal layer of a specified thickness on the surface of the patterned silicon wafer is accomplished by ion beam deposition.

[0018] Optionally, a metal layer of a specified thickness is deposited on the surface of the patterned silicon wafer, wherein the thickness of the metal layer is greater than 0.5 μm and less than 1.0 μm.

[0019] Optionally, taking out the silicon wafer after metal deposition and performing preliminary wetting includes:

[0020] The silicon wafer after metal deposition is taken out and immersed in acetone to initially wet the photoresist covered with the metal layer, wherein the soaking time is 0.4-0.6 hours.

[0021] Optionally, the adhesive film is peeled off in a set direction, wherein the set direction is selected so that the adhesion between the adhesive film and the metal layer is greater than the adhesion between the metal layer and the photoresist, so as to separate the metal layer adhered to the photoresist from the photoresist.

[0022] The method of the embodiment of the present application optimizes the metal layer stripping process, reduces the metal pattern sidewall residue phenomenon after stripping, improves the uniformity of the metal pattern, and improves the performance of the device using the stripping process as the electrode patterning method.

[0023] The above description is only an overview of the technical solution of the present application. In order to more clearly understand the technical means of the present application, it can be implemented in accordance with the contents of the specification. In order to make the above and other purposes, features and advantages of the present application more obvious and easy to understand, the specific implementation methods of the present application are listed below. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Various other advantages and benefits will become apparent to those of ordinary skill in the art by reading the detailed description of the preferred embodiments below. The accompanying drawings are only for the purpose of illustrating the preferred embodiments and are not to be considered as limiting the present application. Also, the same reference symbols are used throughout the accompanying drawings to represent the same components. In the accompanying drawings:

[0025] Figure 1 The basic process diagram of the method for improving the uniformity of metal layer peeling pattern in the embodiment of the present application is shown;

[0026] Figure 2 This is a schematic diagram of the metal layer of the embodiment of the present application being attached to the side wall of the pattern;

[0027] Figure 3 This is the morphology of the metal pattern without the adhesive film assisted peeling;

[0028] Figure 4 This is the metal pattern morphology of the adhesive film assisted peeling in the embodiment of the present application. DETAILED DESCRIPTION

[0029] The exemplary embodiments of the present disclosure will be described in more detail below with reference to the accompanying drawings. Although the exemplary embodiments of the present disclosure are shown in the accompanying drawings, it should be understood that the present disclosure can be implemented in various forms and should not be limited by the embodiments set forth herein. On the contrary, these embodiments are provided to enable a more thorough understanding of the present disclosure and to fully convey the scope of the present disclosure to those skilled in the art.

[0030] The present application embodiment provides a method for improving the uniformity of metal layer peeling pattern, such as Figure 1 As shown, including:

[0031] Step 001, photoresist coating: coating a positive photoresist on the surface of the silicon wafer after the patterning is completed;

[0032] Step 002, photoresist exposure, selecting a desired patterned mask to perform exposure processing on the photoresist in the intended exposure area;

[0033] Step 003, photoresist development: using a developer to pattern the exposed photoresist to dissolve the photoresist above the corresponding pattern and retain the photoresist at other positions as a mask for metal layer deposition;

[0034] Step 004, metal layer deposition: depositing a metal layer of a specified thickness on the surface of the patterned silicon wafer;

[0035] Step 005, initial infiltration of photoresist: taking out the silicon wafer after metal deposition and performing initial infiltration;

[0036] Step 006, attaching an adhesive film: after the infiltration, attaching an adhesive film on the surface of the metal layer;

[0037] Step 007, peeling off the metal layer with the adhesive film: peeling off the adhesive film in a set direction to separate the metal layer adhered to the photoresist from the photoresist;

[0038] Step 008, remove the photoresist, complete.

[0039] In a specific example, the thickness uniformity of the positive photoresist coated on the surface of the silicon wafer is required to be less than 5%.

[0040] In a specific example, depositing a metal layer of a specified thickness on the surface of a patterned silicon wafer is accomplished by ion beam deposition.

[0041] In a specific example, a metal layer of a specified thickness is deposited on the surface of a patterned silicon wafer, wherein the thickness of the metal layer is greater than 0.5 μm and less than 1.0 μm. Figure 2 After the metal layer is deposited on the surface of the silicon wafer, the metal layer is attached to the side wall of the pattern.

[0042] In a specific example, taking out the silicon wafer after metal deposition and performing preliminary wetting includes:

[0043] The silicon wafer after metal deposition is taken out and immersed in acetone to initially wet the photoresist covered with the metal layer, wherein the soaking time is 0.4-0.6 hours.

[0044] In a specific example, the adhesive film is peeled off in a set direction, wherein the set direction is selected so that the adhesion between the adhesive film and the metal layer is greater than the adhesion between the metal layer and the photoresist, so as to separate the metal layer adhered to the photoresist from the photoresist.

[0045] The method of the embodiment of the present application provides a method for improving the uniformity of the metal layer peeling pattern by using an adhesive film to assist peeling, such as Figure 3 , Figure 4 As shown in the figure, the metal pattern sidewall residue phenomenon is significantly reduced, and the yield rate is significantly improved. After the metal layer is peeled off by the adhesive film, the photoresist and the stripping agent are in full contact, so that the metal pattern sidewall is easier to detach from the photoresist surface, improving the morphology uniformity of the metal pattern and improving the performance of the device using the stripping process as an electrode patterning method.

[0046] It should be noted that in the various embodiments of the present application, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also includes other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, an element defined by the sentence "includes a ..." does not exclude the presence of other identical elements in the process, method, article or device including the element.

[0047] The serial numbers of the above-mentioned embodiments of the present application are for description only and do not represent the advantages or disadvantages of the embodiments.

[0048] Through the description of the above implementation methods, those skilled in the art can clearly understand that the above-mentioned embodiment methods can be implemented by means of software plus a necessary general hardware platform, and of course by hardware, but in many cases the former is a better implementation method. Based on such an understanding, the technical solution of the present application, or the part that contributes to the prior art, can be embodied in the form of a software product, which is stored in a storage medium (such as ROM / RAM, a magnetic disk, or an optical disk), and includes a number of instructions for a terminal (which can be a mobile phone, a computer, a server, an air conditioner, or a network device, etc.) to execute the methods described in each embodiment of the present application.

[0049] The embodiments of the present application are described above in conjunction with the accompanying drawings, but the present application is not limited to the above-mentioned specific implementation methods. The above-mentioned specific implementation methods are merely illustrative and not restrictive. Under the guidance of the present application, ordinary technicians in this field can also make many forms without departing from the purpose of the present application and the scope of protection of the claims, all of which are within the protection of the present application.

Claims

1. A method for improving the uniformity of metal layer peeling pattern, characterized in that: include: Coating positive photoresist on the surface of the silicon wafer after patterning; Select the required patterned mask to expose the photoresist in the area to be exposed; The exposed photoresist is patterned using a developer to dissolve the photoresist above the corresponding pattern and retain the photoresist at other locations as a mask for metal layer deposition; Depositing a metal layer of specified thickness on the surface of the patterned silicon wafer; Take out the silicon wafer after metal deposition and perform preliminary infiltration; After infiltration, an adhesive film is attached to the surface of the metal layer; Peel off the adhesive film in the set direction to separate the metal layer and the photoresist adhered to the photoresist; Remove the photoresist and you're done.

2. The method for improving the uniformity of metal layer peeling pattern according to claim 1, wherein: The thickness uniformity of the positive photoresist coated on the surface of the silicon wafer is required to be less than 5%.

3. The method for improving the uniformity of metal layer peeling pattern according to claim 1, wherein: Deposition of a metal layer of specified thickness on the surface of a patterned silicon wafer is accomplished by ion beam deposition.

4. The method for improving the uniformity of metal layer peeling pattern according to claim 3, wherein: A metal layer of a specified thickness is deposited on the surface of a patterned silicon wafer, wherein the thickness of the metal layer is greater than 0.5 μm and less than 1.0 μm.

5. The method for improving the uniformity of metal layer peeling pattern according to claim 1, wherein: Take out the silicon wafer after metal deposition and perform preliminary wetting including: The silicon wafer after metal deposition is taken out and immersed in acetone to initially wet the photoresist covered with the metal layer, wherein the soaking time is 0.4-0.6 hours.

6. The method for improving the uniformity of metal layer peeling pattern according to claim 1, wherein: The adhesive film is peeled off in a set direction, wherein the set direction is selected so that the adhesion between the adhesive film and the metal layer is greater than the adhesion between the metal layer and the photoresist, so as to separate the metal layer and the photoresist adhered to the photoresist.

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