TW201835971A - A method for lithography patterning - Google Patents

Abstract

A method for lithography patterning includes forming a material layer over a substrate; exposing a portion of the material layer to a radiation; and removing the exposed portion of the material layer in a developer, resulting in a patterned material layer. The developer comprises water, an organic solvent, and a basic solute. In an embodiment, the basic solute is less than 30% of the developer by weight.

Description

   Patterning method for lithography process   

The present disclosure relates to a semiconductor device and a manufacturing method thereof. In particular, it relates to a method for patterning a lithographic process.

From now on, the semiconductor integrated circuit (IC) industry has experienced exponential growth. The development of integrated circuit materials and design technology has led to the generation of integrated circuits, and the new generation has smaller and more complex circuits than the previous generation. During the evolution of integrated circuits, an increase in functional density (such as the number of interconnected components per wafer area) is usually accompanied by a reduction in geometric dimensions (such as the smallest component (or line) that can be produced using process technology). In general, scaling down the process can increase production efficiency and reduce related costs. At the same time, scaling down the process also increases the complexity of processing and manufacturing integrated circuits.

For example, the lithography process is a method of transferring integrated circuit patterns to a semiconductor wafer. In the lithography process, a photoresist film is coated on the surface of the wafer, and then a photoresist pattern is formed by exposure and development. Subsequently, a photoresist pattern is used to etch the wafer to form an integrated circuit. The quality of the photoresist pattern directly affects the quality of the final integrated circuit. As the scaling-down process continues, the line edge roughness (LER) and line width roughness (LWR) of the photoresist pattern become more important. There are several factors that affect the line edge roughness / line width roughness of the photoresist pattern, and one of them is a developing solution, such as a chemical solution for developing an exposed photoresist film. Currently, an alkaline aqueous developer is used in a positive tone development (PTD) process, and a developer containing an organic solvent is used in a negative tone development (NTD) process. The former often causes photoresist expansion problems and photoresist pattern collapse problems, while the latter cannot provide sufficient photoresist contrast. Therefore, a new photoresist developer is needed.

In some embodiments, the present disclosure relates to a method for patterning a lithographic process. The method includes forming a material layer on a substrate, and exposing a portion of the material layer to light. The method further includes removing an exposed portion of the material layer in a developing solution to generate a patterned material layer, wherein the developing solution includes water, an organic solvent, and an alkaline solute.

The features of several embodiments have been outlined above, so those skilled in the art can better understand the aspects of this disclosure. Those skilled in the art should understand that they can easily use this disclosure as a basis to design or retouch other processes and structures to achieve the same purpose and / or achieve the same advantages as the embodiments described herein. Those skilled in the art should also understand that this kind of equal structure does not depart from the spirit and scope of this disclosure, and those who are familiar with this art can make various changes, substitutions and decorations without departing from the spirit and scope of this disclosure.

100‧‧‧ Method

102‧‧‧step

104‧‧‧step

106‧‧‧ steps

108‧‧‧ steps

110‧‧‧step

200‧‧‧Semiconductor

202‧‧‧ Substrate

204‧‧‧patterned layer / hard mask layer

204A‧‧‧Patterned hard mask layer

206‧‧‧material layer

206A‧‧‧Unexposed part / Photoresist pattern

206B‧‧‧Exposure

208‧‧‧Irradiated beam

210‧‧‧Developer

300‧‧‧ Extreme Ultraviolet Lithography Process System

302‧‧‧Irradiation light source

306‧‧‧ Concentrating optical element

308‧‧‧Mask

310‧‧‧Mask Platform

312‧‧‧projection optics

314‧‧‧ substrate platform

400‧‧‧Developing tools

402‧‧‧Substrate Platform

404‧‧‧Sports Agency

406‧‧‧Nozzle

408‧‧‧container

500‧‧‧method

508‧‧‧step

610‧‧‧Developer

Read the following detailed description and the corresponding drawings to understand the multiple aspects of this disclosure. It should be noted that many features in the drawings are not drawn according to the standard practice in the industry. In fact, the dimensions of the features can be arbitrarily increased or decreased to facilitate the clarity of the discussion.

FIG. 1 is a flowchart of a method for patterning a lithographic process according to a plurality of aspects of the present disclosure.

FIG. 2A, FIG. 2B, FIG. 2C, FIG. 2D, FIG. 2E, and FIG. 2F are schematic cross-sectional views of a target pattern according to some embodiments of the present disclosure.

3 and 4 are apparatuses using the method of FIG. 1 according to some embodiments of the present disclosure.

FIG. 5 is a flowchart of another method for patterning a lithographic process according to the present disclosure.

FIG. 6 is a schematic cross-sectional view of forming a target pattern in a process stage according to some embodiments of the present disclosure.

The following will clearly illustrate the spirit of this disclosure with drawings and detailed descriptions. Any person with ordinary knowledge in the technical field who understands the embodiments of this disclosure can be changed and modified by the techniques taught in this disclosure. Depart from the spirit and scope of this disclosure. For example, describing "the first feature is formed on or above the second feature", in the embodiment will include the first feature and the second feature having direct contact; and will also include the first feature and the second feature as indirect The contact has additional features formed between the first feature and the second feature. In addition, the disclosure will reuse component numbers and / or text in multiple examples. The purpose of repetition is to simplify and clarify, and does not itself determine the relationship between the various embodiments and / or the configuration in question.

In addition, relative vocabulary such as "below", "below", "below", "above" or "up" or similar words are used in this article to facilitate the description of an element shown in the drawings Or relationship to another element or feature. In addition to describing the orientation of the device in the drawings, the term relative orientation includes different orientations of the device under use or operation. When the device is additionally set (rotated 90 degrees or other facing orientation), the relative vocabulary of orientation used in this article can also be interpreted accordingly.

Generally speaking, the present disclosure relates to a method for manufacturing a semiconductor device, and more particularly to a composition and a method of using the photoresist film for development exposure in a lithography process. In the photolithography process patterning, the photoresist film is exposed to irradiation light, for example: exposure to deep ultraviolet (DUV) light, extreme ultraviolet (EUV) light, or electron beam (e-beam) irradiation After the light, the photoresist film is developed in a developing solution (chemical liquid). The developing solution removes a portion of the photoresist film, thereby forming a photoresist pattern including a line pattern and / or a groove pattern. Subsequently, the photoresist pattern is used as an etching mask in the subsequent etching process, and the pattern is transferred to the underlying patterned layer.

Generally speaking, the photoresist film used for development exposure has two types of processes: a positive tone development (PTD) process and a negative tone development (NTD) process. The positive development process uses a positive developer. The negative development process uses a negative developer. The term "positive developer" as used herein refers to a region that selectively dissolves and removes an exposed photoresist film that is not below a first critical value (such as an exposure dose value). As used herein, the term "negative developer" means to selectively dissolve and remove unexposed or underexposed areas of the photoresist film, such as areas where the exposure is not above the second critical value. The first threshold value and the second threshold value may be the same or different, depending on the parameters of the photoresist material and the developing solution. In the following disclosure, the term “unexposed region” of the photoresist film (or photoresist layer) includes both unexposed and underexposed photoresist film regions.

At present, the commonly used positive and negative developers each have their own disadvantages in advanced lithography processes. For example, commonly used positive-type developers often cause photoresist expansion. During the positive development process, it was observed that the exposed area of the photoresist film can expand to or exceed 100%. Photoresist expansion increases the line edge roughness (LER) and line width roughness (LWR) of the developed photoresist pattern. Another problem with the commonly used positive developer is that the developed photoresist pattern sometimes collapses due to the excessive surface tension generated by the positive developer. In the commonly used negative developing solution, the problem of photoresist expansion and photoresist pattern collapse are usually not found. However, negative developers do not produce as good photoresist contrast as positive developers, resulting in high line edge roughness, high line width roughness, and / or low patterning fidelity. The object of this disclosure is to provide a positive-type developer, which has a low-line edge roughness, a low-line-width roughness, and a high-resistance contrast photoresist film. The new developer will meet the requirements of contemporary advanced lithography processes, including extreme ultraviolet lithography and electron beam lithography.

FIG. 1 is a flowchart of a method 100 for patterning a substrate (such as a semiconductor wafer) according to various aspects of the present disclosure. The method 100 may be implemented in whole or in part by a system using a deep ultraviolet lithography process, an extreme ultraviolet lithography process, an electron beam lithography process, an x-ray lithography process, and other lithography processes. In some embodiments, an extreme ultraviolet lithography process is used as a main example. In addition, additional operations may be provided before, during, and after the method 100 is performed. In order to perform the additional operations of the method, the operations described in part may be replaced, eliminated, or moved. The method 100 is merely an example, and this should not be used to limit the disclosure beyond what is explicitly stated in the scope of the patent application. The method 100 is described with reference to FIGS. 2A to 2F as follows, in which a semiconductor device 200 is manufactured using an embodiment of the method 100. In addition, in some embodiments, FIG. 3 and FIG. 4 are schematic diagrams illustrating equipment used by the method 100.

In various embodiments, the semiconductor device 200 is an intermediate stage device during the manufacture of an integrated circuit or a part of the integrated circuit. This device may include static random access memory and / or logic circuits; passive components such as resistors, Capacitors and inductors; active components such as: p-type field effect transistors, n-type field effect transistors, fin field effect transistors, other multi-gate field effect transistors, metal oxide semiconductor field effect transistors, complementary metal oxide Semiconductor transistors, bipolar transistors, high-voltage transistors, high-frequency transistors, other active components, and combinations thereof.

In step 102 of the method 100 (as shown in FIG. 1), a substrate 202 is provided. Referring to FIG. 2A, the substrate 202 includes one or more layers of material or composition. In some embodiments, the substrate 202 is a semiconductor substrate (eg, a wafer). In other embodiments, the substrate 202 includes crystalline silicon. In another embodiment, the substrate 202 includes other element semiconductors such as germanium; compound semiconductors such as silicon carbide, gallium arsenide, indium arsenide, and indium phosphide; or alloy semiconductors such as silicon germanium carbide, gallium phosphide Arsenic, and indium gallium phosphide. In some embodiments, the substrate 202 may include a silicon on insulator (SOI) that is deformed / pressurized to improve performance. The substrate 202 may include an epitaxial region, a doped region, and one or more semiconductors. Element or part of a semiconductor element, conductive and / or non-conductive layer, and / or other suitable features and layers.

In other embodiments, the substrate 202 is a mask substrate. The mask substrate may include a low thermal expansion material, such as quartz, silicon, silicon carbide, or a silicon oxide-titanium oxide compound. Furthermore, the substrate 202 can be used to make a deep UV mask, an extreme UV mask, or other types of mask substrates.

As shown in FIG. 2A, in some embodiments, the substrate 202 includes a patterned layer 204. In some embodiments, the patterned layer 204 is composed of, for example, amorphous silicon (a-Si), silicon dioxide, silicon nitride, silicon oxynitride (SiON), silicon carbon nitride (SiCN), silicon carbide, and nitride. A hard mask layer of titanium, other suitable materials, or a combination of the above. In various embodiments, the patterned layer 204 may include a high-k dielectric layer, a gate layer, a hard mask layer, an interface layer, a cover layer, a diffusion / barrier layer, a dielectric layer, a conductive layer, and others. A suitable layer, and / or a combination of the above.

In step 104 of the method 100 (as shown in FIG. 1), a material layer 206 is formed on the substrate 202 (as shown in FIG. 2B). Referring to FIG. 2B, in some embodiments, a liquid polymer material is spin-coated on the substrate 202 to form a material layer 206. In some embodiments, the material layer 206 further undergoes a soft baking process and a hard baking process. In some embodiments, the material layer 206 is a light-sensitive layer, for example, a photoresist including i-line photoresist, a deep ultraviolet photoresist including krypton fluoride (KrF) photoresist and argon fluoride (ArF) photoresist, Extreme ultraviolet photoresist, electron beam photoresist, and ion beam photoresist. In some embodiments, the material layer 206 is a photoresist sensitive to extreme ultraviolet light, and the material layer 206 is used for positive-type development. For example, under extreme ultraviolet light, the material layer 206 can be added to the positive-type development. Solubility in liquid. For convenience, the material layer 206 will be referred to as a photoresist film (or photoresist) 206 in the following discussion. In some embodiments, the photoresist film 206 includes a photo-acid generator (PAG), and the photo-acid generator generates an acid after being irradiated with light. The acid can catalyze the cleavage of the acid labile group (ALG) from the main chain polymer of the photoresist film. When the acid-labile group leaves the main chain polymer, the branch units of the polymer will become a carboxylic group. This increases the solubility of the polymer in the positive developer and allows the exposed areas of the photoresist film to be removed by the developer, while the unexposed areas remain insoluble and become a masking element for subsequent processes.

In some embodiments, before forming the material layer 206, the method 100 forms an anti-reflection coating on the patterned layer 204, and then forms a material layer 206 on the anti-reflection coating. For example, the anti-reflective coating can be a material including a nitrogen-free anti-reflective coating (NFARC) layer, such as: silicon dioxide, silicon carbide (SOC), and plasma to enhance the chemical vapor phase. Deposit silicon oxide (PECVD-SiO2), other suitable materials, or a combination of the above. In other embodiments, in the method 100, more than one layer is formed between the patterned layer 204 and the material layer 206.

In step 106 of the method 100 (as shown in FIG. 1), the irradiation beam 208 (as shown in FIG. 2C) of the photoresist film 206 in the lithography process system 300 is exposed. Referring to FIG. 2C, the irradiation beam 208 may be i-line (365 nm), deep ultraviolet light, such as erbium fluoride excimer laser (248 nm) or argon fluoride molecular laser (193 nm), Extreme ultraviolet radiation (eg, 13.8 nm), electron beam, x-ray, ion beam, or other appropriate irradiation light. Step 106 may be performed in the air, in a liquid (immersion lithography process), or in a vacuum (eg, extreme ultraviolet lithography process and electron beam lithography process). In some embodiments, by using the irradiation beam 208 to pattern a mask having an integrated circuit pattern, such as a transmission mask or a reflection mask, such masks may include things like phase shifting and / or optical proximity correction ( optical proximity correction (OPC) resolution enhancement technology. In another embodiment, without using a mask, the irradiation light beam 208 is directly modulated in an integrated circuit pattern (unmasked lithography process). In some embodiments, the irradiation light beam 208 is an extreme ultraviolet irradiation light and the lithography process system 300 is an extreme ultraviolet lithography process system. An example of the extreme ultraviolet lithography process system 300 is shown in FIG. 3.

Referring to FIG. 3, the extreme ultraviolet lithography process system 300 includes an irradiation light source 302 that generates an irradiation light beam 208, a condensing optical element 306, a mask platform 310 on which a fixed mask 308 is fixed, a projection optical element 312, and a fixed inclusion The substrate 202 and the substrate platform 314 of the element 200 of the photoresist film 206. In the present disclosure, the extreme ultraviolet lithography process system 300 may be a step exposure machine or a scan exposure machine.

The irradiation light source 302 provides an irradiation light beam 208, which has a wavelength in the extreme ultraviolet range, such as about 1 nm to 100 nm. In some embodiments, the illumination beam 208 has a wavelength of about 13.5 nanometers. The condensing optical element 306 includes a multilayer-coated light collector and a plurality of grazing angle incidence mirrors. The light-concentrating optical element 306 is configured to collect and shape the irradiation light beam 208, and provide a gap of the irradiation light beam 208 to the mask 308. The mask 308 is also called a light mask or reticle, and contains a target pattern of one or more integrated circuit elements. The mask 308 provides a patterned mask image to illuminate the light beam 208. The mask 308 is a reflective mask in some embodiments, and may include resolution enhancement techniques such as phase shifting techniques and / or optical proximity correction. The mask 308 is fixed on the mask platform 310 by vacuuming to provide accurate position and movement of the mask 308 during the alignment, focusing, leveling, and exposure operations of the extreme ultraviolet lithography process system 300.

The projection optical element 312 includes one or more lenses and a plurality of reflectors. The lens may have a magnification of less than one, thus reducing the patterned mask image of the mask 308 to the element 200, especially to the photoresist film 206. The substrate 200 is used to fix the component 200 to provide the accurate position and movement of the mask 308 during the alignment, focusing, leveling, and exposure operations of the extreme ultraviolet lithography process system 300, so that the patterned mask of the mask 308 The image is repeatedly exposed on the photoresist film 206 (although other lithographic processes are also possible). In the positive-type developing solution, the exposed portion of the photoresist film 206 becomes soluble.

As in the embodiment shown in FIG. 2C, the portion 206B of the photoresist film 206 is exposed by a sufficient amount of irradiation light 208, so that the portion 206B can be removed by a positive developing solution as described below, and the photoresist film 206 A portion 206A is an unexposed area. In some embodiments, the photoresist film 206 includes a photoacid generator, and the semiconductor device 200 may undergo one or more post-exposure baking processes. The post-exposure baking process uses a photoacid generator to accelerate the generation of acid, and accelerates the process of photoresist pattern formation.

Step 108 (see FIG. 1) of the method 100 is constructed according to a plurality of aspects of the present disclosure, and the exposed photoresist film 206 is developed in a developing solution 210. Referring to FIG. 2D, a developing solution 210 is applied to the photoresist film 206, including both an exposed portion 206B and an unexposed portion 206A. In some embodiments, the developing solution 210 is a positive developing solution, and the developing solution dissolves and removes the exposed portion 206B to generate a photoresist pattern 206A (as shown in FIG. 2E). In the example shown in Fig. 2E, the photoresist pattern 206A is represented by a line pattern. However, the following also applies to the photoresist pattern represented by the groove.

As mentioned above, the commonly used positive and negative developers each have their own shortcomings in today's advanced lithography processes: the former usually causes the problem of photoresist expansion and photoresist pattern collapse, and the latter produces photoresist Insufficient contrast. At the same time, the commonly used positive developer produces high photoresistance contrast, while the commonly used negative developer does not cause photoresist expansion. The inventors of this disclosure have found a way to combine the advantages of both positive and negative developers while avoiding the respective disadvantages of the developers.

Commonly used positive-type developing solutions use an alkaline (or dissociated alkaline) aqueous solution, such as a solution using water as a solvent and alkali as a solute. The base may be organic or inorganic. The inventors of this disclosure believe that water solvents may be the cause of the expansion of the photoresist film. Water has a small molecular weight (molecular weight = 18), and water molecules can easily penetrate the photoresist film and cause the photoresist film to swell. Therefore, reducing the water content in the positive developer can cause less photoresist expansion.

Commonly used negative developers use organic materials (rather than water) as solvents. Organic solvents have a relatively large (compared to water) molecular weight. The inventors of the present disclosure believe that the large molecular weight of the organic solvent is a negative-type developer that usually does not cause the photoresist film to swell. However, the commonly used negative developing solution lacks a solute (especially an alkaline solute), and the lack of this solute may be the reason why the negative developing solution cannot produce high photoresistance contrast.

According to the construction of the present disclosure, the developer 210 combines the advantages of a commonly used positive developer with the advantages of a commonly used negative developer. In some embodiments, the developing solution 210 includes at least one organic solvent and at least one alkaline solute. Further, in the embodiment, the weight percent concentration of the at least one organic solvent in the developing solution is greater than 50%. More examples of the developing solution 210 are provided below. In several experiments, the embodiment of the developer 210 produced a photoresist pattern with smaller line edge roughness and line width roughness than the commonly used positive developer, and provided a photoresist pattern higher than that of the commonly used negative developer. Photoresist contrast.

In some embodiments, the developing solution 210 includes an alkaline solute in a range of greater than 0% but less than 30% by weight. For example, the developing solution 210 may include an alkaline solute having a concentration of about 0% to about 20% by weight, such as an alkaline solute having a concentration of about 2% to about 10% by weight.

In some embodiments, the developing solution 210 further contains water with a concentration of less than 50% by weight in the developing solution. In some examples, the developing solution 210 includes an organic solvent with a concentration of about 70% by weight, an alkaline solute with a concentration of about 10% by weight, water with a concentration of about 20% by weight, and other additives, such as One or more surfactants.

In some embodiments, the organic solvent of the developing solution 210 includes at least one of the following: a hydroxyl (OH) functional group, a hydrogen nitrogen (NH) functional group, a nitrogen dihydrogen (NH ₂ ) functional group, and a hydrogen sulfur (SH) functional group , A methoxy (OMe) functional group, and an ethoxy (OEt) functional group. In some embodiments, the organic solvent of the developing solution 210 has a molecular weight of less than 300, because having too large a molecular weight may reduce the effectiveness of the developing solution 210 in dissolving and exposing the photoresist film. However, the molecular weight of the organic solvent is not small enough to cause the photoresist film to swell like a commonly used positive developing solution. Further, in this embodiment, the organic solvent has a molecular weight larger than that of water. For example, the organic solvent may have a molecular weight greater than 50. In some embodiments, the organic solvent of the developing solution 210 is at least one of the following: ethylene glycol, diethylene glycol, and propylene glycol.

In some embodiments, the basic solute of the developing solution 210 is an alkali ion, a non-alkali ion, or a combination thereof. For example, the basic solute may be an alkali ion containing hydroxide ions. In various embodiments, the basic solute is an alkali ion having a molecular weight of less than 400, because having an excessively large molecular weight may reduce the effectiveness of the developing solution 210 in dissolving and exposing the photoresist film.

In other embodiments, the basic solute may be a non-alkali ion, such as a base containing an amine. For example, the basic solute may include a primary amine, a secondary amine, or a tertiary amine. Further, in this embodiment, for the same reason as described above, the molecular weight of the non-alkali ion may be less than 300. In some embodiments, the basic solute is ethylenediamine. In another embodiment, the alkaline solute of the developing solution 210 does not have a metal, so as to avoid the metal content remaining in the developing photoresist. For example, the basic solute may be tetramethylammonium hydroxide (TMAH), tetrabutylammonium hydroxide (TBAH), ethylenediamine (EDA), triethyleneamine, pyridine, Guanidine salt, pyridine, or another organic base.

In various embodiments, the developing solution 210 has a surface tension of less than 50 millinewtons / meter. Low surface tension reduces the possibility of shrinking the photoresist pattern. In addition, in some embodiments, the developing solution 210 may include some additives, such as one or more surfactants. For example, the surfactant can be anionic, non-ionic, or hydrophilic ionic. The surfactant helps reduce the surface tension of the developing solution 210.

With continued reference to FIG. 2D, a developing solution 210 is applied to the photoresist film 206. The exposed portion 206B of the photoresist film 206 is dissolved by the developing solution 210, leaving an unexposed portion 206A (including the underexposed portion) on the substrate 202. For convenience of discussion, the unexposed portion 206A is also referred to as a photoresist pattern 206A. Due to the properties of the developing solution 210 described above, the photoresist pattern 206A has very smooth edges and side walls (such as low line edge roughness and rough line width) and is well defined (ie, high developing contrast) .

In some embodiments, a developing solution 210 is applied to the element 200 in the developing tool 400, and an embodiment of the developing tool 400 is shown in FIG. 4. Referring to FIG. 4, the developing tool 400 is a part of a cluster tool for a semiconductor manufacturing process. After exposing the photoresist film 206 to the extreme ultraviolet lithography process system 300 (as shown in FIG. 2C and FIG. 3), the component 200 is transferred to the developing tool 400 to apply a developing solution 210 on the photoresist film 206. As shown in FIG. 4, the developing tool 400 applies the developing solution 210 through a spin-coating development process, that is, the developing tool 400 sprays the developing solution 210 onto the photoresist film 206, and at the same time, the element 200 starts from the vertical axis Spin.

As shown in FIG. 4, the developing tool 400 includes a substrate platform 402, and the substrate platform 402 is designed to fix the component 200 including the photoresist film 206. During the spin-coating development process, the substrate platform 402 is operated to spin, and the component 200 fixed to the substrate platform 402 is caused to spin accordingly. For example, the substrate platform 402 includes a vacuum chuck, an electric chuck, or other suitable mechanism to fix the component 200. The developing tool 400 further includes a movement mechanism 404 integrated with the substrate platform 402 to operate the substrate platform 402 and the component 200 fixed on the substrate platform in various motion modes. In some embodiments, the motion mechanism 404 includes a motor for driving the substrate platform 402 and the component 200 to drive the substrate platform 402 and the component 200 to rotate at a specific speed during various operations such as development and cleaning.

When the element 200 spins, the developing solution 210 is sprayed on the element 200 through the nozzle 406. The developer solution 210 is stored in a container 408 and transferred to a nozzle 406 by a transfer device including a pipe. The developing solution 210 may be transferred using a pump, a compressed gas, or other mechanism.

In various embodiments, the developing solution 210 may be continuously sprayed onto the element 200. Alternatively, the developer may be applied by other means such as a puddle development process. The method 100 may include further operations after step 108 to complete the photoresist pattern 206A. For example, a dip operation may be performed by de-ionized (DI) water to clean the element 200 to remove residues and particles, and / or perform post-development baking (PDB)) The process is to harden the photoresist pattern 206A, thereby increasing the structural stability of the photoresist pattern.

In step 110 of the method 100 (as shown in FIG. 1), the integrated circuit pattern is transferred from the photoresist pattern 206A to the substrate 202 (as shown in FIG. 2F). In some embodiments, step 110 includes etching the substrate 202 using the photoresist pattern 206A as an etching mask. In some embodiments, the patterned layer 204 is a hard mask layer. Further, in this embodiment, the integrated circuit pattern is first transferred from the photoresist pattern 206A to the hard mask layer 204, and then transferred to other layers of the substrate 202. For example, the hard mask layer 204 may be etched through the opening of the photoresist pattern 206A using dry (plasma) etching, wet etching, and / or other etching methods. For example, the dry etching process may include: an oxygen-containing gas, a fluorine-containing gas (eg, carbon tetrafluoride (CF ₄ ), sulfur hexafluoride (SF ₆ ), difluoromethane (CH ₂ F ₂ ), trifluoro Methane (CHF ₃ ) and / or hexafluoroethane (C ₂ F ₆ )), chlorine-containing gases (for example; chlorine, chloroform (CHCl ₃ ), carbon tetrachloride (CCl ₄ ), and / or boron trichloride ( BCl ₃ )), bromine-containing gas (for example: hydrogen bromide (HBr) and / or tribromomethane (CHBR ₃ )), iodine-containing gas, other suitable gas and / or plasma, or a combination thereof. For example, the wet etching process may include dilute hydrofluoric acid; potassium hydroxide solution; ammonia; tetramethylammonium hydroxide; a solution containing hydrofluoric acid, nitric acid, and / or acetic acid; or other suitable wet Etching in an etchant. During the etching of the hard mask layer 204, the photoresist pattern 206A may be partially or completely consumed. In some embodiments, any remaining portion of the photoresist pattern 206A may be peeled off, leaving a patterned hard mask layer 204A on the substrate 202, as shown in FIG. 2F.

Although not shown in FIG. 1, the method 100 may continue to form a final pattern or form an integrated circuit element on the substrate 202. In some embodiments, the substrate 202 is a semiconductor substrate, and the method 100 is performed to form a fin-type field effect transistor structure. For example, in step 110, a plurality of active fins are formed in the semiconductor substrate 202. Due to the low line edge roughness and rough line width of the photoresist pattern 206A, the active fins have a uniform critical dimension. In another embodiment, the method 100 is performed to form a plurality of gate electrodes in the semiconductor substrate 202. Due to the smooth sidewalls of the photoresist pattern 206A, the gate electrode has a uniform gate length. In another embodiment, a metal line is formed in the multilayer interconnection structure as a target pattern. For example, a metal line may be formed in the interlayer dielectric layer of the substrate 202, and the dielectric layer is etched in step 110 to include a plurality of trenches. Subsequently, the method 100 is performed to fill the trench with a conductive material such as a metal; and grind the conductive material using a process such as chemical mechanical planarization (CMP) to expose the patterned interlayer dielectric layer so as to interlayer dielectric. A metal line is formed in the electrical layer. The above is a device / structure manufactured and / or improved according to the multi-faceted method 100 and the developing solution 210 of the present disclosure, which should not be used to limit the present disclosure.

FIG. 5 is a method 500 of patterning a substrate (such as a semiconductor wafer) according to a plurality of aspects of the disclosure in some embodiments. The method 500 is an example, and this attempt should not be used to limit the scope of the disclosure beyond the scope of patent application. The content explicitly stated in the paragraph may provide additional operations before, during, and after performing the method 500; in order to perform the additional operations of the method, the operations described in the section may be replaced, eliminated, or moved. The method 500 is described with reference to FIG. 6, which is a schematic cross-sectional view of the semiconductor device 200 in a manufacturing stage of the method 500.

The method 500 is similar to the method 100 in many respects. One difference between the method 500 and the method 100 is the development of the exposed photoresist film 206. Referring to FIG. 5, the method 500 also includes steps 102, 104, 106, and 110 in the method 100 described above, and is not repeated here for simplicity. After the method 500 proceeds to step 106, the operation proceeds to step 508 to develop the exposed photoresist film 206 with the developing solution 610. Referring to FIG. 6, a developing solution 610 is applied on the photoresist film 206. In some embodiments, the developing solution 610 includes at least one organic solvent, water, and at least one alkaline solute. Further, in some embodiments, the weight percent concentration of water in the developer is greater than 20%. According to the developer 610 constructed in this disclosure, the advantages of the commonly used positive developer and the commonly used negative developer are combined. The reason is similar to that discussed in the developer 210 described above. Further, since the photoresist film generally has a hydrophobic portion (such as a resin polymer main chain) and a hydrophilic portion (such as a hydroxyl functional group), part of the water in the developing solution 610 helps to increase the dissolution rate of the exposure photoresist. And to reduce the loss of unexposed photoresist during the development process. Further examples of the developing solution 610 are described below. In a number of experiments, the embodiment of the developing solution 610 can produce a photoresist with a dissolution contrast higher than that of commonly used positive and negative developers.

In some embodiments, the weight percent concentration of at least one alkaline solute in the developing solution 610 is greater than 0% but less than 30%. For example, the developing solution 610 may include an alkaline solute having a concentration of about 0% to about 20% by weight, such as an alkaline solute having a concentration of about 2% to about 10% by weight. In some embodiments, the developing solution 610 includes at least one organic solvent with a concentration greater than 5% by weight. For example, the developing solution 610 may include an organic solvent with a concentration of more than 5% by weight, an alkaline solute with a concentration of less than 30% by weight, water with a concentration of more than 20% by weight, and other additives, such as one or more Surfactants. In some embodiments, the developing solution 610 may include an organic solvent with a concentration of more than 50% by weight, an alkaline solute with a concentration of less than 30% by weight, water with a concentration of more than 20% by weight, and other additives, such as one or Multiple surfactants.

In some embodiments, the organic solvent of the developing solution 610 includes at least one of the following: a hydroxyl (OH) functional group, a hydrogen nitrogen (NH) functional group, a nitrogen dioxide (NH ₂ ) functional group, and a hydrogen sulfur (SH) functional group , A methoxy (OMe) functional group, and an ethoxy (OEt) functional group. In other embodiments, the organic solvent of the developing solution 610 includes an ester (RO (CH ₂ ) _n OR) functional group, where n is an integer greater than or equal to two. In some examples, n is equal to 2 or 3, each R may be the same or different, and R may be a hydrogen atom or an alkyl group having less than 10 carbon atoms. In some embodiments, the organic solvent of the developing solution 610 is at least one of the following: ethylene glycol, diethylene glycol, and propylene glycol. In some embodiments, the organic solvent of the developing solution 610 has a molecular weight of less than 500, and the molecular weight of the organic solvent is greater than the molecular weight of water to reduce the expansion of the photoresist film.

In some embodiments, the basic solute of the developing solution 610 is an alkali ion, a non-alkali ion, or a combination thereof. For example, the solute may comprise an alkaline hydroxide ions (OH ^-) of alkali ions, alkali ions can have a molecular weight of less than 400. In another embodiment, the basic solute may be a non-alkali ion, such as a base containing an amine. For example, the basic solute may include a primary amine, a secondary amine, or a tertiary amine, and the molecular weight of the non-basic ion may be less than 300. For example, the basic solute may be tetramethylammonium hydroxide, tetrabutylammonium hydroxide, ethylenediamine, trivinylamine, pyridine, guanidinium salt, pyridine, or another organic base. In some embodiments, the alkaline solute of the developing solution 610 does not have a metal, so as to avoid the metal content remaining in the developing photoresist.

In various embodiments, the surface tension of the developing solution 610 is less than 50 millinewtons / meter. Low surface tension reduces the possibility of photoresist pattern collapse. In addition, in some embodiments, the developing solution 610 may include additives, such as one or more surfactants, to help reduce the surface tension of the developing solution 610. For example, the surfactant can be anionic, non-ionic, or hydrophilic ionic.

With continued reference to FIG. 6, a developing solution 610 is applied on the photoresist film 206, and the exposed portion 206B of the photoresist film 206 is dissolved by the developing solution 610 to generate a photoresist pattern 206A (as shown in FIG. 2E), as shown in FIG. 2E In the example, the photoresist pattern 206A is represented by a line pattern, however, the method 500 is equally applicable to the photoresist pattern represented by a trench. Due to the properties of the developing solution 610 described above, the photoresist pattern 206A has low line edge roughness, low line width roughness, and high photoresist contrast. Referring to FIG. 5, after step 508, the method 500 proceeds to step 110 to transfer the integrated circuit pattern from the photoresist pattern 206A to the substrate 202 (as shown in FIG. 2F). This is not repeated.

One or more embodiments of the present disclosure provide numerous benefits to the formation of semiconductor devices and semiconductor devices, but the disclosure should not be limited in this way. For example, the photoresist developer constructed according to the present disclosure provides superior performance in the positive development process of advanced lithography, such as: deep ultraviolet lithography process, extreme ultraviolet lithography process, and electron beam lithography process. The photoresist developing solution reduces the surface roughness of the photoresist pattern, such as the reduction of line edge roughness and line width roughness, and provides high patterning fidelity. The above-mentioned photoresist developer is particularly advantageous in the manufacture of nanometer semiconductors, in which the uniformity of critical dimensions has become a key factor in circuit performance.

Claims (1)

    A method for patterning a lithographic process, comprising: forming a material layer on a substrate; exposing a portion of the material layer to an irradiated light; and removing the exposed portion of the material layer in a developing solution. A patterned material layer is generated, wherein the developing solution includes water, an organic solvent, and an alkaline solute.