Semiconductor manufacturing process for improving photoresist residue

Abstract

The invention discloses a semiconductor manufacturing process for improving photoresist residue, which comprises the following steps: providing a nitrogen-containing layer, forming a bottom anti-reflection coating on the nitrogen-containing layer, diffusing nitrogen ions in the nitrogen-containing layer into the bottom anti-reflection coating, performing a hot plate baking manufacturing process on the nitrogen-containing layer, and forming the bottom anti-reflection coating on the bottom anti-reflection coating. Nitrogen ions in the bottom anti-reflection coating layer are volatilized from the surface, a photoresist is formed on the bottom anti-reflection coating layer after the hot plate baking manufacturing process, and the photoresist is patterned by an exposure and development manufacturing process.

Description

Technical Field

[0001] The invention relates to a semiconductor manufacturing process, and more particularly to a semiconductor manufacturing process for improving photoresist residues through a hot plate baking manufacturing process. Background Art

[0002] Over the past few decades, the semiconductor integrated circuit (IC) industry has experienced rapid growth and development. The advancement and evolution of materials, circuit design, and manufacturing processes have enabled manufacturers to produce smaller, more sophisticated and complex integrated circuits than previous generations. In the process of the semiconductor industry's development, manufacturing process methods, equipment, and materials have continued to improve in order to meet the demand for smaller component feature sizes.

[0003] The photolithography process (also known as the lithography process) is a technology for developing semiconductor patterns onto a substrate, that is, forming a photosensitive layer on a substrate, and then radiating light through a pre-patterned mask to produce a pattern on the photosensitive layer. Although photolithography equipment and related technologies have made significant progress in reducing the line width of components, further development and improvement are still needed. For example, the actual features and contours of the photoresist after patterning are not accurate enough to accurately replicate the desired pattern onto the semiconductor substrate. For example, after the patterning step and the development step are completed, unwanted photoresist parts may still remain on the substrate, affecting the authenticity of the pattern.

[0004] In the prior art, after the photoresist or bottom anti-reflective coating (BARC) as a photosensitive layer is formed on the substrate, it may be idle for a period of time due to various factors such as the order of the manufacturing process before the photolithography manufacturing process is carried out (i.e., the standby time is too long). This may cause the impurity particles in the layer structure in contact with the photoresist to diffuse into the photoresist, thereby causing the properties of the photoresist to change and affecting the subsequent photolithography manufacturing process. For example, if the layer structure in contact with the photoresist contains nitrogen components, the nitrogen ions diffuse into the photoresist and react with the hydrogen ions in the photoresist to produce a neutralization reaction, so that the original photoacid component at the interface becomes less, so that the photoresist at this location is likely to remain after the photolithography manufacturing process, resulting in a reduction in key dimensions such as the line width (ADI CD) after development. Summary of the invention

[0005] In view of the above-mentioned problem that the photoresist is easily deteriorated due to being left for too long, resulting in the problem of photoresist residue, the present invention proposes a novel semiconductor manufacturing process, which is characterized in that the substrate is first subjected to a hot plate baking action before the photoresist is formed, so that the nitrogen ions in the bottom anti-reflective coating (BARC) are volatilized from the surface. In this way, the nitrogen ions can be prevented from entering the photoresist due to the long idle time after the subsequent photoresist is formed, causing the photoresist to deteriorate, and then causing the photoresist to remain on the substrate after exposure and development.

[0006] The present invention aims to provide a semiconductor manufacturing process for improving photoresist residue, the steps of which include providing a nitrogen-containing layer, forming a bottom anti-reflection coating on the nitrogen-containing layer, wherein nitrogen ions in the nitrogen-containing layer diffuse into the bottom anti-reflection coating, performing a hot plate baking process on the nitrogen-containing layer to volatilize the nitrogen ions in the bottom anti-reflection coating from the surface, forming a photoresist on the bottom anti-reflection coating after the hot plate baking process, and performing an exposure and development process to pattern the photoresist.

[0007] These and other objects of the present invention will become more apparent to the reader after reading the following detailed description of the preferred embodiment which is described in various figures and drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0008] Figure 1 A block diagram of a semiconductor manufacturing process for improving photoresist residue in a preferred embodiment of the present invention; and

[0009] Figures 2 to 6 It is a cross-sectional schematic diagram of a semiconductor manufacturing process for improving photoresist residue in a preferred embodiment of the present invention.

[0010] Please note that all illustrations in this manual are of a legend nature. For the sake of clarity and convenience of illustration, the components in the illustrations may be exaggerated or reduced in size and proportion. Generally speaking, the same reference symbols in the figures will be used to indicate corresponding or similar component features after modification or in different embodiments.

[0011] Main component symbols

[0012] 100 Nitrogen-containing layer

[0013] 102 Bottom anti-reflective coating

[0014] 104 Photoresist

[0015] H + Hydrogen ions

[0016] H1 hot plate baking process

[0017] N - Nitrogen ions

[0018] P1 Photolithography Process

[0019] Steps S1 to S4 DETAILED DESCRIPTION

[0020] Now, the exemplary embodiments of the present invention will be described in detail below, and the features described will be shown with reference to the accompanying drawings so that the reader can understand and achieve the technical effects. The reader will understand that the description in the text is only by way of example and is not intended to limit the present invention. The various embodiments of the present invention and the various features that do not conflict with each other in the embodiments can be combined or reset in various ways. Without departing from the spirit and scope of the present invention, modifications, equivalents or improvements to the present invention are understandable to those skilled in the art and are intended to be included in the scope of the present invention.

[0021] Readers should be able to easily understand that the meanings of "on", "over" and "above" in this case should be interpreted in a broad manner, so that "on" not only means "directly on" something but also includes the meaning of being "on" something with an intervening feature or layer, and "on" or "above" not only means "on" or "above" something but also includes the meaning of being "on" or "above" something with no intervening features or layers (i.e., directly on something). In addition, spatially related terms such as "under", "below", "lower", "over", "upper", etc. may be used herein for convenience of description to describe the relationship between one element or feature and another or more elements or features, as shown in the accompanying drawings.

[0022] As used herein, the term "substrate" refers to a material onto which subsequent materials are added. The substrate itself may be patterned. The material added on top of the substrate may be patterned or may remain unpatterned. In addition, the substrate may include a wide range of semiconductor materials, such as silicon, germanium, gallium arsenide, indium phosphide, etc. Alternatively, the substrate may be made of a non-conductive material such as glass, plastic, or a sapphire wafer.

[0023] As used herein, the term "layer" refers to a portion of a material including an area having a thickness. A layer may extend over the entirety of a lower or upper structure, or may have an extent that is less than the extent of a lower or upper structure. In addition, a layer may be an area of ​​a homogeneous or inhomogeneous continuous structure having a thickness that is less than the thickness of a continuous structure. For example, a layer may be located between the top and bottom surfaces of a continuous structure or between any horizontal faces at the top and bottom surfaces. A layer may extend horizontally, vertically and / or along an inclined surface. A substrate may be a layer, which may include one or more layers, and / or may have one or more layers thereon, above and / or below it. A layer may include multiple layers. For example, an interconnect layer may include one or more conductors and contact layers (where contacts, interconnects and / or vias are formed) and one or more dielectric layers.

[0024] The reader can generally understand the term at least in part from the usage in the context. For example, depending at least in part on the context, the term "one or more" as used herein can be used to describe any feature, structure, or characteristic in a singular sense, or can be used to describe a combination of features, structures, or characteristics in a plural sense. Similarly, depending at least in part on the context, terms such as "a", "an", "the", or "said" can also be understood to convey singular usage or to convey plural usage. In addition, the term "based on" can be understood to not necessarily be intended to convey an exclusive set of factors, but can allow for the presence of additional factors that are not necessarily explicitly described, which also depends at least in part on the context.

[0025] The reader can further understand that when the words "include" and / or "contain" are used in this specification, they specify the existence of the stated features, regions, wholes, steps, operations, elements and / or parts, but do not exclude the possibility of the existence or addition of one or more other features, regions, wholes, steps, operations, elements, parts and / or their combinations.

[0026] Now the following will be based on Figure 1 The semiconductor manufacturing process for improving photoresist residue in the preferred embodiment of the present invention is described, and each step can be referred to at the same time. Figures 2 to 6 A schematic cross-section of the process is provided to provide a clearer and more detailed understanding of the evolution of relevant components and features in the process.

[0027] First, in step S1, a nitrogen-containing layer is provided, and a bottom anti-reflective coating (BARC) is formed on the nitrogen-containing layer. Figure 2As shown, the nitrogen-containing layer 100 may be a layer structure formed on a semiconductor substrate, such as a hard mask layer or a barrier layer formed on an etching target layer, and its material may be silicon nitride (SiN) or titanium nitride (TiN). For the sake of simplicity, the layer structure and features below the nitrogen-containing layer 100 are omitted in the figure. It may be an organosiloxane (organosiloxane) or a spin-on carbon layer (Spin-On-Carbon, SOC). The function of the bottom anti-reflective coating 102 is to reduce the reflection and standing wave problems in the development process. In the actual manufacturing process, after the bottom anti-reflective coating 102 is formed on the nitrogen-containing layer 100, it may be idle due to various factors such as the manufacturing process sequence, resulting in the nitrogen ions N in the nitrogen-containing layer 100 in contact with the bottom anti-reflective coating 102. - The nitrogen content in the bottom anti-reflective coating 102 is increased by diffusion into the bottom anti-reflective coating 102 .

[0028] After the bottom anti-reflection coating 102 is formed, in step S2, Figure 3 As shown, a hot plate baking process H1 is performed to make the nitrogen ions N in the bottom anti-reflective coating 102 - Due to heat diffusion, the nitrogen is volatilized from the surface of the bottom anti-reflective coating 102. In this way, the internal nitrogen content of the bottom anti-reflective coating 102 before the photoresist is formed can be effectively reduced, and its standby time (Q time) can be extended. In a preferred embodiment of the present invention, the temperature of the hot plate baking process H1 can be between 120 and 140°C, and the duration can be between 60 and 90 seconds. After the hot plate baking process H1, the standby time from the formation of the bottom anti-reflective coating 102 to the formation of the photoresist can exceed eight hours, which greatly increases the manufacturing process sequencing margin.

[0029] After the hot plate baking process H1, the next step is step S3. Figure 4 As shown, a photoresist 104 is formed on the bottom anti-reflective coating 102. In the embodiment of the present invention, the photoresist 104 is formed on the surface of the bottom anti-reflective coating 102 and is in direct contact therewith, and can be a G-line / I-line photoresist, a KrF photoresist, an ArF photoresist, or an EUV photoresist, a positive or negative photoresist, and is formed by spin coating, but is not limited thereto.

[0030] Most common photoresists use the principle of chemical amplification, which mixes a photosensitive photoacid generator with a polymer to form a photoresist, and uses the photoacid generator to generate photoacid in the exposure area, and then catalyzes the polymer to change its polarity during post-exposure baking, thereby defining the pattern of the exposure and non-exposure areas. +The content is an important factor in the development process. In the prior art, after the photoresist as the photosensitive layer is formed on the bottom anti-reflective coating, it may be idle for a period of time due to various factors such as the order of the production process before the photolithography process is carried out (i.e., the standby time is too long). This will cause the nitrogen ions (which may come from the nitrogen-containing layer 100) in the bottom anti-reflective coating in contact with the photoresist to diffuse into the photoresist and react with the hydrogen ions therein, so that the original photoacid component at the interface between the two becomes less. In this way, the photoresist at this location is likely to remain after the photolithography process and is not dissolved by the developer, resulting in a reduction in key dimensions such as the line width (ADI CD) after development.

[0031] In contrast, in the embodiment of the present invention, since the bottom anti-reflective coating 102 is first subjected to a hot plate baking process H1 before the photoresist 104 is formed, the nitrogen ions N in the bottom anti-reflective coating 102 are - Therefore, even if the waiting time after the photoresist 104 is formed is too long, there will be no nitrogen ions N in the bottom anti-reflective coating 102. - Diffusion into the photoresist 104 causes the properties of the photoresist 104 to change, so that unnecessary portions of the photoresist 104 do not remain after development. This is a major feature of the present invention.

[0032] Re-reference Figure 4 . After the photoresist 104 is formed, a photolithography process P1 is then performed in step S4 to pattern the photoresist 104. The photolithography process P1 may include two steps of exposure and development, wherein the exposure step may use light radiation in the full spectrum of ultraviolet (300-450nm), G-line (436nm), I-line (365nm), deep ultraviolet (DUV, including 248nm and 193nm) and extreme ultraviolet (EUV) bands, and expose the pattern on the photomask to the photoresist 104 corresponding to these bands by scanning and stepping, so that the irradiated photoresist 104 parts will be photosensitive and deteriorated. The development step may be to use a developer such as tetramethylammonium hydroxide (TMAH) or xylene to dissolve the unnecessary photoresist 104 parts (which may be the light-receiving parts or the non-light-receiving parts), so that the desired semiconductor pattern is formed in the photoresist 104, which serves as a mask for the subsequent etching process.

[0033] Please refer to Figure 5 After the photolithography process P1, the photoresist 104 on the bottom anti-reflection coating 102 is patterned to form the desired semiconductor pattern. In the present invention, since the bottom anti-reflection coating 102 is first subjected to the hot plate baking process H1 before the photoresist 104 is formed, there will be no nitrogen ions N in the bottom anti-reflection coating 102. -Diffusion into the photoresist 104 causes the properties of the photoresist 104 to change, so that the unnecessary parts of the photoresist 104 after development will not remain on the bottom anti-reflective coating 102, so that the key dimensions such as the post-development line width (ADICD) required by the manufacturing process can be accurately achieved. This is a major feature of the present invention. After the photolithography process P1, the photoresist 104 can undergo another baking process to solidify and shape. It should be noted that in the present invention, the baking before forming the photoresist 104 and the baking after the photolithography process P1 have different characteristics and functions. The focus of the present invention is to bake before forming the photoresist 104 to allow the nitrogen ions N in the bottom anti-reflective coating 102 to - Diffusion from the surface.

[0034] Please refer to Figure 6 After the photoresist 104 is patterned, the patterned photoresist 104 can be used to perform semiconductor manufacturing processes such as etching and ion implantation. For example, a dry etching process is performed using the patterned photoresist 104 as an etching mask to remove the bottom anti-reflective coating 102 and the nitrogen-containing layer 100 below, so as to transfer the defined semiconductor patterns to the layer structures.

[0035] The above descriptions are only preferred embodiments of the present invention. All equivalent changes and modifications made according to the claims of the present invention should fall within the scope of the present invention.

Claims

1. A semiconductor manufacturing process for improving photoresist residue, comprising: providing a nitrogen-containing layer; forming a bottom anti-reflective coating on the nitrogen-containing layer, wherein nitrogen ions in the nitrogen-containing layer diffuse into the bottom anti-reflective coating; Performing a hot plate baking process to volatilize nitrogen ions in the bottom anti-reflective coating from the surface; After the hot plate baking process, forming a photoresist on the bottom anti-reflective coating; as well as The photoresist is patterned by performing exposure and development processes. 2 . The semiconductor manufacturing process for improving photoresist residue as claimed in claim 1 , wherein the material of the nitrogen-containing layer is silicon nitride or titanium nitride.

3. The semiconductor manufacturing process for improving photoresist residue as claimed in claim 1, wherein the waiting time after the hot plate baking process to the formation of the photoresist exceeds eight hours. 4 . The semiconductor manufacturing process for improving photoresist residue as claimed in claim 1 , wherein the temperature of the hot plate baking process is between 120 and 140° C., and the duration is between 60 and 90 seconds.

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