Expandable negative photoresist with suspended material and method for reducing horn shape in spacer oxide using expandable negative photoresist

Abstract

The invention relates to an expandable negative photoresist and a method for adjusting the profile of a spacer oxide by using the expandable negative photoresist. The expandable negative photoresist comprises a high polymer material, a suspension material and a photoacid generator. The suspension material comprises a plurality of expandable molecules.

Description

[0001] This invention claims priority to U.S. Patent No. 18 / 934,430 (i.e., priority date "November 1, 2024"), the contents of which are incorporated herein by reference in their entirety. Technical Field

[0002] This invention relates to a negative photoresist and a method for adjusting the cross-sectional profile of spacer oxides, and more specifically, to an expandable negative photoresist having a suspending material and a method for reducing the horn shape in spacer oxides using this expandable negative photoresist. Background Technology

[0003] Semiconductor components are used in a wide range of electronic applications, including personal computers, mobile phones, digital cameras, and other electronic devices. The size of semiconductor components continues to shrink to meet the ever-increasing demands for computing power. However, the challenges brought about by this shrinking size are becoming increasingly frequent and impactful. Therefore, it remains a challenge to improve quality, yield, performance, and reliability while reducing complexity.

[0004] Spacers and spacer oxides are commonly used in the manufacturing process of semiconductor devices to ensure the correct spacing and functionality between components. Due to the requirements for small linewidths and spacing, such as critical dimensions (CD) of less than 50 nm, and more complex manufacturing processes, including doubling the spacing and multiple patterning, ensuring the functional integrity of spacers while avoiding horn shapes remains an ongoing challenge.

[0005] The discussion in the preceding technical paragraphs is for background information only. The statements in the discussion in the preceding technical paragraphs are not an admission that the content disclosed in these paragraphs constitutes prior art of the present invention, and nothing in the discussion in the preceding technical paragraphs should be construed as an admission that any part of the present invention, including the parts in the discussion in the preceding technical paragraphs, constitutes prior art of the present invention. Summary of the Invention

[0006] One aspect of the present invention provides an expandable negative photoresist, comprising: a polymer material, a suspension material, and a photoacid generator (PAG). The suspension material comprises a plurality of expandable molecules.

[0007] In some embodiments, the coefficient of thermal expansion of the suspended material is greater than the coefficient of thermal expansion of the polymer material.

[0008] In some embodiments, the density of the suspended material is less than the density of the polymer material.

[0009] In some embodiments, the expandable molecule is chemically bonded to the polymer material via a chemical bond.

[0010] In some embodiments, a photolytic bond-breaking method is used to break the chemical bond.

[0011] In some embodiments, the polymeric material includes poly(tert-butoxycarboxylated styrene).

[0012] (PBOCSt).

[0013] In some embodiments, the photoacid generator includes triphenylsulfonium hexafluoroantimonate (Ph3SSbF6).

[0014] Another aspect of the present invention provides a method for adjusting the cross-sectional profile of a spacer oxide, comprising: providing a substrate; applying an underlayer on the substrate; forming a first photoresist layer on the underlayer; performing an exposure process on the first photoresist layer to create a second photoresist layer therein; performing a development process on the first and second photoresist layers to form a third photoresist layer and an expandable layer thereon; depositing a spacer oxide layer to cover the third photoresist layer and the expandable layer; and performing a thermal process on the expandable layer to adjust the cross-sectional profile of the spacer oxide. The first photoresist layer includes a first suspension material containing a plurality of first expandable molecules, and the second photoresist layer includes a second suspension material containing a plurality of second expandable molecules. The expandable layer includes the plurality of second expandable molecules. The thermal treatment is performed by activating the plurality of second expandable molecules in the expandable layer.

[0015] In some embodiments, the first photoresist layer is a negative photoresist.

[0016] In some embodiments, the first suspending material is uniformly distributed throughout the first photoresist layer.

[0017] In some embodiments, each of the plurality of first expandable molecules is chemically bonded to a first polymeric material in the first photoresist layer by a chemical bond.

[0018] In some embodiments, the expansion coefficient of the first suspension material is greater than the expansion coefficient of the first polymer material.

[0019] In some embodiments, the density of the first suspension material is less than the density of the first polymer material.

[0020] In some embodiments, the first polymeric material of the first photoresist layer comprises poly(tert-butoxycarboxystyrene) (PBOCSt).

[0021] In some embodiments, each of the plurality of second expandable molecules is separated from a second polymeric material in the second photoresist layer.

[0022] In some embodiments, the expansion coefficient of the second suspension material is greater than the expansion coefficient of the second polymer material.

[0023] In some embodiments, the density of the second suspension material is less than the density of the second polymer material.

[0024] In some embodiments, the second polymeric material of the second photoresist layer comprises poly(4-hydroxystyrene) (PHOSt).

[0025] In some embodiments, the third photoresist layer does not contain the plurality of second expandable molecules, while the expandable layer contains the plurality of second expandable molecules.

[0026] In some embodiments, the method further includes: disposing a mask on the first photoresist layer, wherein the mask includes an unmasked portion that defines a region in the first photoresist layer, and that region will be subsequently exposed.

[0027] In some embodiments, the exposure process is performed using ultraviolet (UV) light.

[0028] In some embodiments, the first photoresist layer also includes a photoacid generator (PAG).

[0029] In some embodiments, the photoacid generator includes triphenylsulfonium hexafluoroantimonate (Ph3SSbF6).

[0030] Another aspect of the present invention provides a method for reducing the trumpet shape of a spacer oxide layer, comprising: providing an underlayer, forming a negative photoresist layer on the underlayer, forming a patterned photoresist layer and an expandable layer on the underlayer through an exposure process and a development process, depositing a spacer oxide layer covering the patterned photoresist layer and the expandable layer, and performing a thermal process to cause the spacer oxide layer to expand outward, thereby reducing the trumpet shape of the spacer oxide layer to be formed in subsequent processes. The negative photoresist layer includes a polymer material, a suspension material, and a photoacid generator (PAG). The suspension material contains a plurality of expandable molecules, and the expandable layer contains a plurality of released expandable molecules. The patterned photoresist layer does not contain released expandable molecules. The thermal process activates the released expandable molecules to expand outward, thereby causing the spacer oxide layer to expand outward.

[0031] In some embodiments, each of the plurality of expandable molecules is chemically bonded to the polymer material of the negative photoresist layer by a chemical bond.

[0032] In some embodiments, the coefficient of thermal expansion of the suspended material is greater than the coefficient of thermal expansion of the polymer material.

[0033] In some embodiments, the density of the suspended material is less than the density of the polymer material.

[0034] In some embodiments, the polymer material of the negative photoresist layer includes poly(tert-butoxycarboxystyrene) (PBOCSt).

[0035] In some embodiments, the photoacid generator includes triphenylsulfonium hexafluoroantimonate (Ph3SSbF6).

[0036] In some embodiments, each of the plurality of released expandable molecules is separated from a polymeric material of the second photoresist layer.

[0037] In some embodiments, a first sidewall of the expandable layer is coplanar with a first sidewall of the patterned photoresist, and a second sidewall of the expandable layer is coplanar with a second sidewall of the patterned photoresist.

[0038] In some embodiments, the plurality of released expandable molecules are obtained by photodegradation bond breaking method.

[0039] Embodiments of the present invention provide a negative photoresist comprising a suspension material containing a plurality of expandable molecules. Furthermore, a method for using the negative photoresist is also proposed to reduce the formation of a trumpet shape in the spacer oxide. By applying this negative photoresist and method, the number of manufacturing steps and costs can be reduced, while improving the yield of the manufacturing process.

[0040] The technical features and advantages of the present invention have been broadly summarized above to provide a better understanding of the detailed description of the invention below. Other technical features and advantages constituting the subject matter of the patent scope of the present invention will be described below. Those skilled in the art to which this invention pertains will understand that the concepts and specific embodiments disclosed below can be readily used to modify or design other structures or processes to achieve the same purpose as the present invention. Those skilled in the art to which this invention pertains will also understand that such equivalent constructions cannot depart from the spirit and scope of the invention as defined by the appended patent claims. Attached Figure Description

[0041] A more comprehensive understanding of the disclosure of this invention can be obtained by referring to the accompanying drawings in conjunction with the embodiments and the scope of the invention patent. It should be noted that, in accordance with industry standard practice, the features are not drawn to scale. In fact, for clarity of discussion, the dimensions of various features can be arbitrarily increased or decreased.

[0042] Figure 1 This is a flowchart illustrating a method for reducing the horn shape of spacer oxides according to some embodiments of the present invention.

[0043] Figures 2 to 9This is a cross-sectional view illustrating an intermediate stage of a method for reducing the horn shape of spacer oxides according to some embodiments of the present invention.

[0044] Figure 10 This is a schematic diagram showing the cross-sectional profile of the spacer oxide before and after adjustment according to some embodiments of the present invention.

[0045] Figures 11 to 15 This is a cross-sectional view illustrating an intermediate stage of a method for reducing the trumpet shape of spacer oxides according to a comparative embodiment of the present invention.

[0046] [Symbol Explanation]

[0047] 10: Method

[0048] 100: Semiconductor substrate

[0049] 102: Bottom Layer

[0050] 102T: Top surface

[0051] 104: Negative photoresist layer

[0052] 104a: Polymer Materials

[0053] 104b: Suspended materials

[0054] 104c: Expandable molecule

[0055] 106: Mask

[0056] 107: Uncovered area

[0057] 109: Exposure of Manufacturing Process

[0058] 112: Exposure layer

[0059] 112a: Polymer Materials

[0060] 112b: Suspended materials

[0061] 112c: Expandable molecule

[0062] 112T: Top surface

[0063] 114: Patterned photoresist

[0064] 116: Expandable layer

[0065] 116T: Top surface

[0066] 117: Development Process

[0067] 118: Spacer oxide layer

[0068] 118': Spacer oxide layer

[0069] 121: Thermal Process

[0070] 304: Photoresist layer

[0071] 306: Translucent and expandable material

[0072] 314: Photoresist layer

[0073] 316: Expandable layer

[0074] 318': Spacer oxide layer

[0075] 321: Thermal Process

[0076] 1121: Lower part

[0077] 1123: Upper part

[0078] A1: Sectional Profile

[0079] B1: Sectional Profile

[0080] C1: Horn shape

[0081] CB: Chemical bond

[0082] D1: Direction

[0083] HDMS: Hexamethyldisilazane

[0084] PAG: Photoacid Generator

[0085] R: Region

[0086] S1: Sidewall

[0087] S2: Sidewall

[0088] S3: Sidewall

[0089] S4: Sidewall

[0090] S11: Steps

[0091] S13: Steps

[0092] S15: Steps

[0093] S17: Steps

[0094] S19: Steps Detailed Implementation

[0095] This invention provides numerous different embodiments or examples for implementing various features of the provided subject matter. Specific examples of components and configurations described below are provided to simplify the invention. Of course, these are merely illustrative and not intended to be limiting. For example, in the following description, forming a first feature on or above a second feature can include embodiments in which the first and second features are formed in direct contact, or embodiments in which an additional feature is formed between the first and second features such that the first and second features may not be in direct contact. Furthermore, element symbols and / or letters may be repeated in various examples. Such repetition is for simplicity and clarity and is not in itself a limitation on the relationship between the various embodiments and / or configurations discussed.

[0096] Furthermore, for ease of description, spatially related terms such as "below," "under," "lower part," "above," "upper part," or other similar terms may be used herein to describe the relative relationship between one element or feature and another shown in the accompanying drawings. In addition to the orientations depicted in the figures, spatially related terms are intended to cover different orientations of the element in use or operation. The element may be oriented in other ways (rotated 90 degrees or otherwise), and the spatially relative descriptors used herein may be interpreted accordingly.

[0097] It should be understood that when a component or layer is referred to as being "connected to" or "coupled to" another component or layer, it may be directly connected to or coupled to the other component or layer, or there may be intermediate components or intermediate layers.

[0098] It should be understood that although various elements may be described herein using terms such as first, second, etc., these elements should not be limited by these terms. Unless otherwise stated, these terms are used only to distinguish one component from another. Thus, for example, the first component, first member, or first part discussed below may be referred to as the second component, second member, or second part without departing from the teachings of the invention.

[0099] Unless the context otherwise indicates, terms such as “identical,” “equal,” “plane,” or “coplanar” as used herein do not necessarily mean exactly the same orientation, layout, location, shape, size, quantity, or other measure when referring to orientation, layout, location, shape, size, quantity, or other measure, but are intended to cover substantially identical orientations, layouts, locations, shapes, sizes, quantities, or other measures within an acceptable range of possible variations (e.g., due to manufacturing processes). The term “substantially” may be used herein to reflect this meaning. For example, articles described as “substantially identical,” “substantially equal,” or “substantially coplanar” may be exactly the same, equal, or coplanar, or may be substantially identical, equal, or coplanar within an acceptable range of possible variations (e.g., due to manufacturing processes).

[0100] In this invention, a semiconductor element generally refers to an element that can operate using the characteristics of a semiconductor, and electro-optic elements, light-emitting display elements, semiconductor circuits and electronic elements are all included in the category of semiconductor elements.

[0101] It should be noted that in the description of this invention, "above" (or "up") corresponds to the direction of the arrow in the Z direction, and "below" (or "down") corresponds to the opposite direction of the arrow in the Z direction.

[0102] Figure 1 This is a flowchart illustrating a method 10 for reducing the horn shape of spacer oxides according to some embodiments of the present invention. Figures 2 to 9 This is a cross-sectional view illustrating an intermediate stage of a method 10 for reducing spacer oxides in a trumpet shape according to some embodiments of the present invention.

[0103] See Figures 1 to 3 In step S11, a semiconductor substrate 100 and a bottom layer 102 can be provided, and a negative photoresist layer 104 can be formed on the bottom layer 102.

[0104] See Figure 2 In some embodiments, the semiconductor substrate 100 may include a main semiconductor substrate. The main semiconductor substrate may be formed of materials such as elemental semiconductors, such as silicon or germanium; compound semiconductors, such as silicon germanium, silicon carbide, gallium arsenide, gallium phosphide, indium phosphide, indium arsenide, indium antimonide, or other group III-V or group II-VI compound semiconductors; or combinations thereof.

[0105] In some embodiments, the semiconductor substrate 100 may include an insulator-on-semiconductor structure comprising, from bottom to top, a handle substrate, an insulating layer, and a topmost semiconductor material layer. The handle substrate and the topmost semiconductor material layer may be formed of the same material as the main semiconductor substrate. The insulating layer may be a crystalline or amorphous dielectric material, such as an oxide and / or a nitride. For example, the insulating layer may be a dielectric oxide, such as silicon oxide. Alternatively, the insulating layer may be a dielectric nitride, such as silicon nitride or boron nitride. Furthermore, the insulating layer may comprise a stack of dielectric oxides and dielectric nitrides, for example, silicon oxide, silicon nitride, and / or boron nitride stacked in any order. The insulating layer may have a thickness between about 10 nm and 200 nm.

[0106] It should be noted that in the description of this invention, when the term "about" is used to modify the amount of a component, ingredient, or reactant of this invention, it refers, for example, to numerical variations that may occur through typical measurement and liquid handling procedures used to prepare concentrates or solutions. Furthermore, variations may occur due to unintentional errors in the measurement procedure, differences in the manufacture, source, or purity of the components used to prepare the composition or to carry out the method, etc. In one aspect, the term "about" means within 10% of the reported value. In another aspect, the term "about" means within 5% of the reported value. In yet another aspect, the term "about" means within 10%, 9%, 8%, 7%, 6%, 5%, 4%, 3%, 2%, or 1% of the reported value.

[0107] See Figure 2 A bottom layer 102 can be disposed on and cover the semiconductor substrate 100. The bottom layer 102 can be used for various purposes and can contain different materials.

[0108] In some embodiments, the bottom layer 102 enhances subsequent coatings (e.g., Figure 3 The adhesion of the negative photoresist layer 104 shown is ensured. This ensures a strong bond between the negative photoresist layer 104 and the semiconductor substrate 100, thereby reducing the risk of delamination and defects.

[0109] Furthermore, the bottom layer 102 can fill in irregularities on the surface of the semiconductor substrate 100, providing a flatter surface and thus achieving better photoresist coating and development results. The bottom layer 102 can also improve the optical performance during lithography processes (e.g., exposure process 109, development process 117, and post-exposure bake (PEB) process), ensuring the uniformity and consistency of the negative photoresist layer 104 during exposure and development, thereby improving pattern accuracy.

[0110] Furthermore, the bottom layer 102 can serve as an isolation layer to prevent interactions between different materials and ensure the stability of electrical performance. It can also act as a buffer layer, absorbing stress that may occur during manufacturing, thereby protecting subsequent film layers from damage. In some deposition processes, the bottom layer 102 can function as a seed layer, promoting the growth or deposition of subsequent materials to ensure good crystalline structure and performance. Finally, the bottom layer 102 can serve as a bottom anti-reflective coating (BARC) layer, reducing light reflection on the substrate surface and improving the resolution and quality of the lithography pattern.

[0111] In some embodiments, the substrate 102 may be formed of a polymer, such as polyimide, polystyrene, poly(methyl methacrylate), PMMA, polyurethane, polyetheretherketone (PEEK), or polyester oxide. In some embodiments, the substrate 102 may be formed of silicon dioxide and silicon nitride. In some embodiments, the substrate 102 may be formed of aluminum oxide (Al2O3). In some embodiments, the substrate 102 may be formed of a low dielectric constant dielectric material, such as silicon oxycarbide (SiOC), or a metal, such as titanium or tantalum.

[0112] See Figure 3 A negative photoresist layer 104 can be formed on top of the bottom layer 102 and cover the bottom layer 102. The negative photoresist layer 104 may include a polymer material 104a, a suspension material 104b, and multiple expandable molecules 104c.

[0113] In some embodiments, the coefficient of thermal expansion of the suspending material 104b is greater than that of the polymer material 104a. As a result, the negative photoresist layer 104 can exhibit stronger expansion characteristics compared to photoresist without the suspending material 104b. Furthermore, the density of the suspending material 104b is lower than that of the polymer material 104a, thus enhancing the suspending properties of the negative photoresist layer 104.

[0114] Polymer material 104a may include poly(tert-butoxycarboxystyrene) (PBOCSt). Suspension material 104b, containing expandable molecules 104c, may be uniformly distributed throughout the negative photoresist layer 104. Chemical bonds CB may form between polymer material 104a and expandable molecules 104c, and these bonds are protected by tert-butyl groups. Due to the presence of expandable molecules 104c, the negative photoresist layer 104 is also referred to as the first expandable photoresist 104.

[0115] It should be noted that the first expandable photoresist 104 is a negative photoresist (or negative-type photoresist). In other words, during the exposure process, the photosensitive material of the first expandable photoresist 104 undergoes a chemical change, resulting in the material in the exposed areas becoming insoluble in the developer, while the material in the unexposed areas remains soluble. Generally, negative photoresist has high resolution, providing sharper edges when creating intricate patterns. Furthermore, negative photoresist typically exhibits good etching resistance in subsequent etching processes, effectively protecting the underlying material.

[0116] See Figure 3 A photoacid generator (PAG), such as triphenylsulfonium hexafluoroantimonate (Ph3SSbF6), can be introduced into the first expandable photoresist 104. Generally, photoacid generators are primarily used in processes involving positive photoresists. In positive photoresists, the photoacid generator produces acid during the exposure process, thus making certain areas of the photoresist more soluble in the developer, thereby forming the desired pattern. In contrast, negative photoresists work by making certain areas of the photoresist less soluble due to exposure. Therefore, photoacid generators are typically not used in negative photoresist processes.

[0117] However, according to some embodiments of the present invention, the first expandable photoresist 104 includes a suspension material 104b containing a plurality of expandable molecules 104c. This composition allows the use of a photoacid generator in the negative photoresist layer 104 to promote the progress of the process reaction; for example, using a photoacid generator to promote photodegradation and bond breaking.

[0118] See Figure 1 , Figure 4 and Figure 5 In step S13, an exposure process 109 can be performed on the first expandable photoresist 104 to form an exposure layer 112 within the first expandable photoresist 104 and to release expandable molecules 104c from the polymer material 104a of the first expandable photoresist 104.

[0119] See Figure 4 During the exposure process 109, a mask (or photomask) 106 with an unmasked portion 107 can be disposed on the first expandable photoresist 104. The unmasked portion 107 defines a region R in the first expandable photoresist 104 that will be exposed. Region R is located at the position where the exposure layer 112 will be formed in a subsequent process.

[0120] A light source, typically ultraviolet or extreme ultraviolet, can be used for the exposure process 109. This light source includes deep ultraviolet (DUV) light with wavelengths ranging from 193 nanometers (nm) to 248 nm and extreme ultraviolet (EUV) light with a wavelength of approximately 13.5 nm.

[0121] During the exposure process 109, when exposed to a light source, photoacid generators, such as triphenylsulfonium hexafluoroantimonate (Ph3SSbF6), decompose and release photoacids. These photoacids can catalyze subsequent chemical reactions, such as promoting deprotection or de-esterification reactions in region R of the first expandable photoresist 104, thereby altering the solubility and other properties of the first expandable photoresist 104 within region R.

[0122] For example, as shown in Equation 1 below, under light irradiation (hv) conditions, Ph3SSbF6 can undergo a photolysis reaction, meaning that Ph3SSbF6 can decompose and generate other chemical substances when exposed to light. Specifically, this reaction produces acidic substances, such as hexafluoroantimonyic acid (HSbF6), and other byproducts. In other words, through a specific reaction mechanism, Ph3SSbF6 may release the acidic substance HSbF6.

[0123]

[0124] PAG: Photoacid generator.

[0125] h: Planck's constant.

[0126] v: Frequency of light.

[0127] Exposed portion: Other products after light exposure.

[0128] Furthermore, during the exposure process 109, expandable molecules 104c can be released from the polymer material 104a of the first expandable photoresist 104 in region R. In other words, as Figure 3 As shown, the chemical bond CB between the polymer material 104a and the expandable molecule 104c is broken, allowing the expandable molecule 104c to move freely within the region R of the first expandable photoresist 104.

[0129] See Figure 5During the exposure process 109, an exposure layer 112 can be formed in the first expandable photoresist 104. In some embodiments, as shown in Equation 2 below, a photodebonding method can be used to continuously release expandable molecules 104c from the polymer material 104a of the first expandable photoresist 104 and form a plurality of expandable molecules 112c in the exposure layer 112.

[0130]

[0131] Expandable molecules.

[0132] As shown in Equation 2, in some embodiments, light, heat, and acid (H+) are present. + Under the influence of ) and expandable molecules Bonded poly(tert-butoxycarboxystyrene) (PBOCSt) can generate poly(4-hydroxystyrene) (PHOSt), carbon dioxide (CO2), and expandable molecules protected by butyl groups. In this equation, PBOCSt can be used as the polymer material 104a of the first expandable photoresist 104, while the expandable molecule before the reaction in Equation 2... The suspension material 104b or the expandable molecule 104c of the first expandable photoresist 104 can be represented.

[0133] The aforementioned PHOSt can be the polymer material 112a of the exposure layer 112, or the expandable molecule protected by butyl groups after the reaction in Equation 2. This can correspond to the suspension material 112b of the exposure layer 112. Furthermore, expandable molecules... It can refer to the expandable molecule 112c.

[0134] In some embodiments, PBOCSt, which does not include tert-butoxycarbonyl (t-BOC) groups, can be a polymer material 104a of the first expandable photoresist 104, while the expandable molecule bonded to the t-BOC groups... It could be suspending material 104b. Furthermore, the expandable molecules before the reaction in Equation 2... The expandable molecule 104c can represent the first expandable photoresist 104. After the reaction in Equation 2, the expandable molecule... It can correspond to the suspension material 112b or expandable molecule 112c of the exposure layer 112.

[0135] Specifically, referring to Equations 1 and 2, under light irradiation (hv) conditions, photoacid generators (PAGs) can produce photoacids, such as HSbF6, which contain substances capable of bonding to expandable molecules 104c (e.g., PBOCSt and expandable molecules). Hydrogen ions (H+) react with the polymer material 104a on the surface. + Under the catalysis of thermal energy from a light source or an additional heating source, an exposure layer 112 can be formed, comprising a polymeric material 112a (e.g., PBOCSt) and a suspension material 112b (e.g., expandable molecules protected by butyl groups after reaction). ).

[0136] It should be noted that PHOSt contains hydroxyl groups (-OH), and compared with PBOCst, it has significantly more hydrophilic (water-absorbing) properties. Furthermore, since there is no bond between the expandable molecule 112c and the polymer material 112a, the expandable molecule 112c can move freely within the exposure layer 112.

[0137] Furthermore, during the reaction, the tert-butyl group continuously releases hydrogen ions (H+). + The hydrogen ions interact with the polymer material 104a bonded to the expandable molecule 104c, producing an amplification effect and prompting multiple iterations to release more expandable molecules 112c. This process is called photodebonding.

[0138] See Figure 5 During the exposure process 109, an exposure layer 112 can be formed at the location of the region R previously defined by the unmasked portion 107 of the mask 106. The exposure layer 112 is composed of a polymer material 112a and a suspension material 112b. In some embodiments, the coefficient of thermal expansion of the suspension material 112b is greater than that of the polymer material 112a. Therefore, compared to photoresist that does not contain the suspension material 112b, the exposure layer 112 exhibits stronger expansion characteristics.

[0139] In some embodiments, the density of the suspending material 112b is less than that of the polymer material 112a, resulting in the exposure layer 112 exhibiting enhanced levitation properties compared to photoresist without the suspending material 112b. The polymer material 112a may include poly(4-hydroxystyrene) (PHOSt), while the suspending material 112b may be composed of multiple expandable molecules 112c.

[0140] Because the exposure layer 112 contains expandable molecules 112c, it is also referred to as the second expandable photoresist 112. It should be noted that the expandable molecules 112c originate from expandable molecules 104c in region R. The key difference between expandable molecules 104c and 112c is that the former is bonded to polymer material 104a, while the latter is not bonded to polymer material 112a. This allows expandable molecules 112c to move freely within region R.

[0141] Due to its lower density, and because the exposure process 109 results in the second expandable photoresist 112 having relatively stronger hydrophilicity, polarity, intermolecular forces, or capillary effects compared to the first expandable photoresist 104, expandable molecules 112c move along direction D1 and accumulate on the top surface 112T of the second expandable photoresist 112. This causes the upper portion 1123 of the second expandable photoresist 112 to exhibit thermal expansion characteristics, while the lower portion 1121 of the second expandable photoresist 112 contains almost no expandable molecules 112c. After the exposure process 109, the photomask 107 can be removed.

[0142] See Figure 1 , Figure 6 and Figure 7 In step S15, the first expandable photoresist 104 and the second expandable photoresist 112 can be developed using a development process 117 to form a patterned photoresist 114 and an expandable layer 116.

[0143] See Figure 6 A developing process 117 using a developer can be performed to develop the second expandable photoresist 112 while simultaneously removing the first expandable photoresist 104. Since the first expandable photoresist 104 is a negative photoresist, after exposure process 109, the unexposed portion of the first expandable photoresist 104 becomes soluble in the developer, resulting in the removal of the unexposed area. In contrast, the photosensitive portion, particularly the second expandable photoresist 112, undergoes a cross-linking or polymerization reaction, making the exposed area insoluble in the developer. Therefore, the exposed area can be retained during developing process 117. In other words, the second expandable photoresist 112 can be retained during developing process 117. In some embodiments, the developer may include potassium hydroxide (KOH), tetramethylammonium hydroxide (TMAH), or the AZ 400K series. Developer.

[0144] See Figure 7After the development process 117, a patterned photoresist 114 and an expandable layer 116 situated on top of the patterned photoresist 114 can be formed. The patterned photoresist 114 is formed from the lower portion 1121 of the second expandable photoresist 112, while the expandable layer 116 is formed from the upper portion 1123 of the second expandable photoresist 112. In some embodiments, a post-exposure baking process can be performed after the development process 117 to improve the chemical stability of the expandable layer 116 in subsequent processes, thereby reducing degradation. Furthermore, the post-exposure baking process can enhance the resolution of the expandable layer 116 by promoting a more uniform chemical reaction during heat treatment, resulting in a clearer pattern. The post-exposure baking process can also help remove photoresist residues from the second expandable photoresist 112, thereby ensuring a clearer pattern is produced during the development process. Furthermore, the post-exposure baking process can enhance the adhesion between the expandable layer 116 and the patterned photoresist 114 and the semiconductor substrate 100, thereby reducing the risk of delamination or defects in subsequent process steps. Finally, the post-exposure baking process can help improve the thickness uniformity of the expandable layer 116, thereby ensuring consistent lithography results across the entire wafer.

[0145] like Figure 7 As shown, in some embodiments, the patterned photoresist 114 may include sidewalls S3 and S4, while the expandable layer 116 may include sidewalls S1 and S2. In some embodiments, the sidewall S1 of the expandable layer 116 may be coplanar with the sidewall S3 of the patterned photoresist 114. Similarly, the sidewall S2 of the expandable layer 116 may be coplanar with the sidewall S4 of the patterned photoresist 114. Furthermore, in some embodiments, the top surface 116T of the expandable layer 116 may be coplanar with the top surface 112T of the second expandable photoresist 112.

[0146] See Figure 7 Since the expandable molecules 112c are concentrated in the upper portion 1123 of the second expandable photoresist 112, there are almost no expandable molecules 112c present in the patterned photoresist 114. In contrast, due to photodebonding and amplification effects, the upper portion 1123 of the second expandable photoresist 112 contains a large number of expandable molecules 112c. As a result, the expandable layer 116 exhibits expandable properties.

[0147] See Figure 1 and Figure 8 In step S17, a spacer oxide layer 118' can be formed to cover the patterned photoresist 114 and the expandable layer 116.

[0148] See Figure 8A deposition process can be performed to form a spacer oxide layer 118'. In some embodiments, the spacer oxide layer 118' can be disposed on the sidewalls S1 and S2 of the expandable layer 116, and on the sidewalls S3 and S4 of the patterned photoresist 114. Furthermore, the spacer oxide layer 118' can be disposed on the top surface 102T of the bottom layer 102 and the top surface 116T of the expandable layer 116. The formation of the spacer oxide layer 118' can involve chemical vapor deposition (CVD), physical vapor deposition (PVD), electroplating, atomic layer deposition (ALD), spin coating, or similar processes. The spacer oxide layer 118' can be formed from materials such as silicon dioxide, alumina, or titanium dioxide, as well as silicon nitride, zirconium dioxide, indium oxide, zinc oxide, or other suitable materials. In some embodiments, the spacer oxide layer 118' can be a single layer or can include a multilayer structure.

[0149] See Figure 1 and Figure 9 In step S19, a thermal process 121 is performed to adjust the cross-sectional profile of the spacer oxide layer 118'.

[0150] See Figure 9 The thermal process 121 can increase the temperature of the expandable layer 116 to activate and expand the expandable molecules 112c in the expandable layer 116. During the expansion process, the expandable molecules 112c may expand outward, causing the spacer oxide layer 118' of the expandable layer 116 to also expand outward. In this way, the shape of the spacer oxide layer 118' is adjusted, thereby helping to avoid the formation of the horn shape C1 of the spacer oxide 118 in subsequent processes, such as... Figure 10 As shown.

[0151] It should be noted that the coefficient of expansion of the suspension material 112b of the second expandable photoresist 112 (which includes expandable molecules 112c) is greater than the coefficient of expansion of the polymer material 112a of the second expandable photoresist 112. As a result, the degree of expansion of the upper portion 1123 of the second expandable photoresist 112 can be greater than the degree of expansion of the lower portion 1121 of the second expandable photoresist 112. In other words, the degree of expansion of the expandable layer 116 can be greater than that of the patterned photoresist 114. Therefore, a desired cross-sectional profile can be formed, for example, a rectangular cross-sectional profile with the upper and lower portions having the same width.

[0152] Figure 10 This is a schematic diagram showing the cross-sectional profile of the spacer oxide before and after adjustment according to some embodiments of the present invention.

[0153] See Figure 10Section profiles A1 and B1 represent the cross-sectional profiles of the spacer oxide before and after adjustment, respectively. Each of section profiles A1 and B1 may include spacer oxide disposed on the sidewalls of the patterned photoresist (lower portion) and on the sidewalls of the expansion layer (upper portion) above the patterned photoresist. Section profiles A1 and B1 may be formed after the above-described method 10 by a subsequent process (e.g., an etching process).

[0154] like Figure 10 As shown, a horn shape C1 may form on top of the spacer oxide 118. It should be noted that the outline A1 is only a schematic diagram. The horn shape may not be very obvious when viewed from the cross-sectional outline A1. In some embodiments, particularly under requirements of small linewidths and close spacing, this horn shape will become more pronounced during complex processes (e.g., spacing doubling processes). This can lead to reduced yields in subsequent processes.

[0155] Therefore, this invention provides a method for pushing a spacer oxide layer outward using the expandable properties of expandable molecules, with the aim of achieving a desired cross-sectional profile specified in the design, such as cross-sectional profile B1. This method can improve the yield of subsequent processes and reduce the number of process steps.

[0156] Figures 11 to 15 This is a cross-sectional view illustrating an intermediate stage of a method for reducing the trumpet shape of spacer oxides according to a comparative embodiment of the present invention.

[0157] See Figure 11 According to a comparative embodiment, a semiconductor substrate 100 and a bottom layer 102 can be provided, and a photoresist layer 304 can be formed on the bottom layer 102. The semiconductor substrate 100 and the bottom layer 102 are... Figure 2 The semiconductor substrate 100 and the underlying layer 102 shown are identical or similar, and repeated descriptions are omitted. The photoresist layer 304 can be a positive photoresist (or a positive-type photoresist) or a negative photoresist (or a negative-type photoresist). It should be noted that the photoresist layer 304 does not contain any expandable molecules. Before proceeding to the next process, a first coating process is performed to spray hexamethyldisilazane (HDMS) onto the photoresist layer 304. The use of HDMS enhances the performance of the photoresist layer 304, thereby improving its stability during exposure and development processes. Furthermore, in high-resolution semiconductor manufacturing, thin photoresist layers are required to achieve a line / space (L / S) ratio and a critical dimension (CD) of less than 50 nanometers.

[0158] See Figure 12According to a comparative embodiment, a second coating process is performed to deposit a layer of light-transmitting expandable material 306 on top of photoresist layer 304 and to cover photoresist layer 304. In some embodiments, light-transmitting expandable material 306 may include a polyester film, such as polyethylene terephthalate (PET), polycarbonate, or silicon-based material.

[0159] See Figure 13 According to a comparative embodiment, an exposure process can be performed, followed by a development process, to create the desired pattern on the substrate 102. In some embodiments, a post-exposure baking process can be performed after the exposure process. The exposure, development, and post-exposure baking processes are similar to... Figures 4 to 6 The exposure, development, and post-exposure baking processes in method 10 are similar, and repeated descriptions are omitted. The pattern formed on the substrate 102 may consist of a photoresist layer 314 and an expandable layer 316 located above the photoresist layer 314.

[0160] See Figure 14 According to a comparative embodiment, a spacer oxide layer 318' can be formed on the pattern and cover the pattern. The formation and material of the spacer oxide layer 318' are related to... Figure 8 The spacer oxide layer 118' is the same as or similar to the spacer oxide layer, and repeated descriptions are omitted.

[0161] See Figure 15 According to a comparative embodiment, a thermal process 321 is performed to raise the temperature of the expandable layer 316, thereby adjusting the cross-sectional profile of the spacer oxide layer 318'. Thermal process 321 and... Figure 9 The thermal process 121 described herein is the same as or similar to that described herein, and repeated descriptions are omitted.

[0162] As described above, in the comparative embodiment, two coating processes are required, including a hexamethyldisilazane coating process and an expandable layer 316 coating process, to adjust the cross-sectional profile of the spacer oxide layer 318'. In contrast, the first expandable photoresist 104 in this embodiment provides a suspension material 104b comprising a plurality of expandable molecules 104c. During the exposure process 109, expandable molecules 112c generated from the release of expandable molecules 104c can aggregate on the top surface of the exposure layer 112. Heat activates the expandable molecules 112c, causing the suspension material 112b to expand outward to adjust the cross-sectional profile A1 of the spacer oxide layer 118', thus preventing the formation of a trumpet shape C1 in the spacer oxide 118 during subsequent processes.

[0163] Embodiments of the present invention provide a negative photoresist layer 104, which includes a suspension material 104b containing a plurality of expandable molecules 104c. Furthermore, a method 10 using the negative photoresist layer 104 is also provided to reduce the formation of the spacer oxide trumpet shape C1. By applying the negative photoresist layer 104 and method 10, the number of manufacturing steps and costs can be reduced, while improving the yield of the manufacturing process.

[0164] One aspect of the present invention provides an expandable negative photoresist, comprising: a polymer material, a suspension material, and a photoacid generator (PAG). The suspension material contains a plurality of expandable molecules.

[0165] In some embodiments, the coefficient of thermal expansion of the suspended material is greater than the coefficient of thermal expansion of the polymer material.

[0166] In some embodiments, the density of the suspended material is less than the density of the polymer material.

[0167] In some embodiments, the expandable molecule is chemically bonded to the polymer material via a chemical bond.

[0168] In some embodiments, a photolytic bond-breaking method is used to break the chemical bond.

[0169] In some embodiments, the polymeric material includes poly(tert-butoxycarboxystyrene) (PBOCSt).

[0170] In some embodiments, the photoacid generator includes triphenylsulfonium hexafluoroantimonate (Ph3SSbF6).

[0171] Another aspect of the present invention provides a method for adjusting the cross-sectional profile of a spacer oxide, comprising: providing a substrate; applying an underlayer on the substrate; forming a first photoresist layer on the underlayer; performing an exposure process on the first photoresist layer to create a second photoresist layer therein; performing a development process on the first and second photoresist layers to form a third photoresist layer and an expandable layer thereon; depositing a spacer oxide layer to cover the third photoresist layer and the expandable layer; and performing a thermal process on the expandable layer to adjust the cross-sectional profile of the spacer oxide. The first photoresist layer includes a first suspension material containing a plurality of first expandable molecules, and the second photoresist layer includes a second suspension material containing a plurality of second expandable molecules. The expandable layer includes the plurality of second expandable molecules. The thermal treatment is performed by activating the plurality of second expandable molecules in the expandable layer.

[0172] In some embodiments, the first photoresist layer is a negative photoresist.

[0173] In some embodiments, the first suspending material is uniformly distributed throughout the first photoresist layer.

[0174] In some embodiments, each of the plurality of first expandable molecules is chemically bonded to a first polymeric material in the first photoresist layer by a chemical bond.

[0175] In some embodiments, the expansion coefficient of the first suspension material is greater than the expansion coefficient of the first polymer material.

[0176] In some embodiments, the density of the first suspension material is less than the density of the first polymer material.

[0177] In some embodiments, the first polymeric material of the first photoresist layer comprises poly(tert-butoxycarboxystyrene) (PBOCSt).

[0178] In some embodiments, each of the plurality of second expandable molecules is separated from a second polymeric material in the second photoresist layer.

[0179] In some embodiments, the expansion coefficient of the second suspension material is greater than the expansion coefficient of the second polymer material.

[0180] In some embodiments, the density of the second suspension material is less than the density of the second polymer material.

[0181] In some embodiments, the second polymeric material of the second photoresist layer comprises poly(4-hydroxystyrene) (PHOSt).

[0182] In some embodiments, the third photoresist layer does not contain the plurality of second expandable molecules, while the expandable layer contains the plurality of second expandable molecules.

[0183] In some embodiments, the method further includes: disposing a mask on the first photoresist layer, wherein the mask includes an unmasked portion that defines a region in the first photoresist layer, and that region will be subsequently exposed.

[0184] In some embodiments, the exposure process is performed using ultraviolet (UV) light.

[0185] In some embodiments, the first photoresist layer also includes a photoacid generator (PAG).

[0186] In some embodiments, the photoacid generator includes triphenylsulfonium hexafluoroantimonate (Ph3SSbF6).

[0187] Another aspect of the present invention provides a method for reducing the trumpet shape of a spacer oxide layer, comprising: providing an underlayer, forming a negative photoresist layer on the underlayer, forming a patterned photoresist layer and an expandable layer on the underlayer through an exposure process and a development process, depositing a spacer oxide layer covering the patterned photoresist layer and the expandable layer, and performing a thermal process to cause the spacer oxide layer to expand outward, thereby reducing the trumpet shape of the spacer oxide layer to be formed in subsequent processes. The negative photoresist layer includes a polymer material, a suspension material, and a photoacid generator (PAG). The suspension material contains a plurality of expandable molecules, and the expandable layer contains a plurality of released expandable molecules. The patterned photoresist layer does not contain released expandable molecules. The thermal process activates the released expandable molecules to expand outward, thereby causing the spacer oxide layer to expand outward.

[0188] In some embodiments, each of the plurality of expandable molecules is chemically bonded to the polymer material of the negative photoresist layer by a chemical bond.

[0189] In some embodiments, the coefficient of thermal expansion of the suspended material is greater than the coefficient of thermal expansion of the polymer material.

[0190] In some embodiments, the density of the suspended material is less than the density of the polymer material.

[0191] In some embodiments, the polymer material of the negative photoresist layer includes poly(tert-butoxycarboxystyrene) (PBOCSt).

[0192] In some embodiments, the photoacid generator includes triphenylsulfonium hexafluoroantimonate (Ph3SSbF6).

[0193] In some embodiments, each of the plurality of released expandable molecules is separated from a polymeric material of the second photoresist layer.

[0194] In some embodiments, a first sidewall of the expandable layer is coplanar with a first sidewall of the patterned photoresist, and a second sidewall of the expandable layer is coplanar with a second sidewall of the patterned photoresist.

[0195] In some embodiments, the plurality of released expandable molecules are obtained by photodegradation bond breaking method.

[0196] Embodiments of the present invention provide a negative photoresist comprising a suspension material containing a plurality of expandable molecules. Furthermore, a method for using the negative photoresist is also proposed to reduce the formation of a trumpet shape in the spacer oxide. By applying this negative photoresist and method, the number of manufacturing steps and costs can be reduced, while improving the yield of the manufacturing process.

[0197] While the invention and its advantages have been described in detail, it should be understood that various changes, substitutions, and alternatives can be made without departing from the spirit and scope of the invention as defined by the patent. For example, many of the processes described above can be implemented using different methods, and other processes or combinations thereof can be substituted for many of the processes described above.

[0198] Furthermore, the scope of this invention is not limited to the specific embodiments of the processes, machinery, manufacturing, material composition, means, methods, and steps described in the specification. Those skilled in the art will understand from the disclosure of this invention that existing or future processes, machinery, manufacturing, material composition, means, methods, or steps that have the same function or achieve substantially the same results as the corresponding embodiments described herein can be used according to this invention. Accordingly, such processes, machinery, manufacturing, material composition, means, methods, or steps are included within the scope of this invention's patent.

Claims

1. An expandable negative photoresist, comprising: A polymer material; A suspended material containing multiple expandable molecules; as well as A photoacid generator.

2. The expandable negative photoresist as described in claim 1, wherein the expansion coefficient of the suspending material is greater than the expansion coefficient of the polymer material.

3. The expandable negative photoresist as described in claim 2, wherein a density of the suspending material is less than a density of the polymer material.

4. The expandable negative photoresist as claimed in claim 1, wherein the expandable molecule is chemically bonded to the polymer material via a chemical bond.

5. The expandable negative photoresist of claim 4, wherein the chemical bond is broken using a photodegradation bond-breaking method.

6. The expandable negative photoresist of claim 1, wherein the polymeric material comprises poly(tert-butoxycarboxystyrene).

7. The expandable negative photoresist of claim 1, wherein the photoacid generator comprises triphenylsulfonium hexafluoroantimonate.

8. A method for adjusting a cross-sectional profile of a spacer oxide, comprising: Provide a substrate; An underlayer is applied onto the substrate; A first photoresist layer is formed on the underlying layer, wherein the first photoresist layer includes a first suspension material, wherein the first suspension material contains a plurality of first expandable molecules; An exposure process is performed on the first photoresist layer to create a second photoresist layer in the first photoresist layer, wherein the second photoresist layer includes a second suspension material, wherein the second suspension material contains a plurality of second expandable molecules; A development process is performed on both the first photoresist layer and the second photoresist layer to form a third photoresist layer and an expandable layer located on the third photoresist layer, wherein the expandable layer includes a plurality of second expandable molecules. Deposit a spacer oxide layer to cover the third photoresist layer and the expandable layer; and A thermal process is performed on the expandable layer to adjust the cross-sectional profile of the spacer oxide.

9. The method of claim 8, wherein the first photoresist layer is a negative photoresist.

10. The method of claim 9, wherein the first suspending material is uniformly distributed throughout the first photoresist layer.

11. The method of claim 10, wherein each of the plurality of first expandable molecules is chemically bonded to a first polymeric material in the first photoresist layer by a chemical bond.

12. The method of claim 11, wherein the coefficient of expansion of the first suspending material is greater than the coefficient of expansion of the first polymeric material.

13. The method of claim 12, wherein the density of the first suspension material is less than the density of the first polymer material.

14. The method of claim 13, wherein the first polymeric material of the first photoresist layer comprises poly(tert-butoxycarboxystyrene).

15. The method of claim 8, wherein each of the plurality of second expandable molecules is separated from a second polymeric material in the second photoresist layer.

16. The method of claim 15, wherein the coefficient of expansion of the second suspension material is greater than the coefficient of expansion of the second polymer material.

17. The method of claim 16, wherein the density of the second suspension material is less than the density of the second polymer material.

18. The method of claim 17, wherein the second polymeric material of the second photoresist layer comprises poly(4-hydroxystyrene).

19. The method of claim 15, wherein the third photoresist layer does not contain the plurality of second expandable molecules, and the expandable layer contains the plurality of second expandable molecules.

20. The method of claim 15, further comprising: A mask is disposed on the first photoresist layer, wherein the mask includes an unmasked portion that defines a region in the first photoresist layer, and that region will be exposed subsequently.

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