Method for removing material coating film by forming an improved freezing-free anti-spacer using a two-layer system
Patent Information
- Authority / Receiving Office
- JP · JP
- Patent Type
- Patents
- Current Assignee / Owner
- TOKYO ELECTRON LTD
- Filing Date
- 2022-05-26
- Publication Date
- 2026-07-31
Smart Images
Figure 0007898077000001 
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Abstract
Description
Technical Field
[0001] Cross - Reference to Related Applications This disclosure claims the benefit of U.S. Provisional Patent Application No. 63 / 195,756, filed on June 2, 2021, which is hereby incorporated by reference in its entirety.
[0002] This disclosure relates to a semiconductor manufacturing method, and more particularly, to facilitating the removal of a coating material covering a structure by utilizing the surface energy difference found in some fluorinated polymers or polymers having long - chain alkyl functional groups that promote segregation on the surface or top layer in a two - layer polymer system.
Background Art
[0003] The description of the background provided herein is for the purpose of generally presenting the background of the disclosure. The research of the inventors within the scope described in this background section, and aspects of the description that would not originally be recognized as prior art at the time of filing, are not to be regarded as either expressly or impliedly admitted as prior art to this disclosure.
[0004] In material processing methodologies (such as photolithography), creating a patterned layer typically involves coating the upper surface of a substrate with a thin layer of a radiosensitive material, such as a photoresist. This radiosensitive material is then converted into a pattern mask that can be used to etch or transfer a pattern onto the underlying layer on the substrate. Patterning of a radiosensitive material generally involves exposure of the radiosensitive material to a radiation source via a reticle (and associated optical system), for example, using a photolithography exposure system. This exposure creates a latent pattern within the radiosensitive material, which can then be developed. Development refers to dissolving and removing a portion of the radiosensitive material to obtain a relief pattern (a raised or recessed pattern). Depending on the tone of the photoresist used and / or the type of developing solvent, the removed portion of the material may be either an irradiated or unirradiated area of the radiosensitive material. The relief pattern can then function as a mask layer defining the pattern.
[0005] The preparation and development of various films used for pattern formation may include heat treatment or baking. For example, a newly coated film may undergo post-coating bake (PAB) to evaporate the solvent and / or increase the rigidity or etching resistance of the structure. Alternatively, post-exposure bake (PEB) may be performed to harden a given pattern to prevent further dissolution. Manufacturing tools for coating and developing onto substrates typically include one or more bake modules. Some photolithography processes involve coating the substrate with a thin film of undercoat anti-reflective coating (BARC), followed by coating with resist, and then, as a process step for creating a microchip, exposing the substrate to a pattern of light. The resulting relief pattern can then be used as a mask or template for additional processing, such as transferring the pattern to a lower layer.
[0006] The relief pattern can be covered with a vapor-deposited material that fills trenches for the final spacer formation. The vapor-deposited material can be further modified to adjust the dimensions of the final spacer. However, in order to develop the modified vapor-deposited material, it may be necessary to remove the vapor-deposited coating to access the modified portion. However, some soft materials cannot withstand etching or chemical mechanical polishing processes. Therefore, a method is desired to remove the coating without affecting the underlying material or causing changes in the dimensions of the modified material. [Overview of the Initiative] [Means for solving the problem]
[0007] This disclosure relates to a method for patterning a substrate, comprising forming a relief pattern on the substrate from a first layer of photoresist on the substrate, wherein the first layer of photoresist comprises a first solubility shift agent and a second solubility shift agent, the photoresist is sensitive to the first solubility shift agent and the second solubility shift agent, and the relief pattern is formed by activating the first solubility shift agent using a chemical line of a pattern and developing the first layer of photoresist; and depositing a polymer mixture onto the relief structure, wherein the polymer mixture fills the openings defined by the relief pattern, covers the relief structure, and the region above the top surface of the relief structure is a coating region, the polymer mixture comprises a first polymer and a second polymer, and the polymer mixture is configured to self-segregate with respect to gravity so that a first film and a second film are formed from the polymer mixture. The present invention relates to a method comprising: a first film containing polymer 1 being formed beneath a second film containing polymer 2, wherein the first and second films are formed such that the second film fills a coating region, the first film being sensitive to a second solubility shift agent and having a sensitivity threshold lower than that of the photoresist, and the second film being soluble in a first developer; activating the second solubility shift agent and diffusing it from the relief structure to the first film to a predetermined diffusion length, wherein the second solubility shift agent is activated so as to satisfy the sensitivity threshold of the first film without satisfying the sensitivity threshold of the photoresist, the diffusion region formed on the first film becoming soluble in the first developer, while the photoresist remains insoluble in the first developer; and developing a substrate to remove the soluble diffusion region of the second film and the first film.
[0008] The Disclosure further relates to a method for patterning a substrate, comprising: forming a relief pattern on the substrate from a first layer of photoresist on the substrate, wherein the first layer of photoresist comprises a first solubility shift agent and a second solubility shift agent, the photoresist is sensitive to the first solubility shift agent and the second solubility shift agent, the relief pattern is formed by activating the first solubility shift agent using a chemical line of a pattern and developing the first layer of photoresist; and depositing a resin overcoat onto the relief structure, wherein the resin overcoat fills the openings defined by the relief pattern, covers the relief structure, and the region above the top surface of the relief structure is a coating region, the resin overcoat comprises a resin mixture comprising a first resin and a second resin, and the resin overcoat is self-segregating with respect to gravity so that a first film and a second film are formed from the resin overcoat. The present invention relates to a method comprising: a configuration wherein a first film containing a first resin is formed beneath a second film containing a second resin, and the first and second films are formed such that the second film fills a coating region, the first film is sensitive to a second solubility shift agent and has a sensitivity threshold lower than that of the photoresist, and the second film is soluble in a first developer; activating the second solubility shift agent and diffusing it from the relief structure to the first film to a predetermined diffusion length, wherein the second solubility shift agent is activated so as to satisfy the sensitivity threshold of the first film without satisfying the sensitivity threshold of the photoresist, and the diffusion region formed on the first film becomes soluble in the first developer, while the photoresist remains insoluble in the first developer; and developing the substrate to remove the soluble diffusion region of the second film and the first film.
[0009] The Disclosure further relates to a method for patterning a substrate, comprising: receiving a substrate having features defining partially filled openings; depositing a polymer mixture onto the substrate, wherein the polymer mixture fills the openings defined by the features, covers the features, and the area above the top surface of the features is a coating region, the polymer mixture comprises a first polymer and a second polymer, and the polymer mixture is configured to self-segregate with respect to gravity such that a first film and a second film are formed from the polymer mixture, the first film comprising the first polymer being formed below the second film comprising the second polymer, the first and second films being formed such that the first film partially fills the defined openings while the second film fills the remaining portion of the defined openings and fills the coating region, the second film being sensitive to a particular solvent while the first film is insoluble in a particular solvent; and developing the substrate with a particular solvent to remove the second film, leaving the first film in the defined openings.
[0010] It should be noted that this summary section does not specify all embodiments and / or progressively novel aspects of the invention as described in this disclosure or claims. Instead, the summary of the invention provides only a preliminary consideration of different embodiments and corresponding novelty aspects. For further details and / or anticipated aspects of the invention and embodiments, readers should refer to the sections on embodiments for carrying out the invention of this disclosure and the corresponding drawings, which are discussed further below.
[0011] Various embodiments of this disclosure, proposed as examples, will be described in detail with reference to the following figures. In the figures, similar numbers refer to similar elements. [Brief explanation of the drawing]
[0012] [Figure 1A] This is a cross-sectional substrate segment showing a substrate including a relief pattern, according to an embodiment of the present disclosure. [Figure 1B]This is a cross-sectional substrate segment showing the deposition of material on a relief pattern according to an embodiment of the present disclosure. [Figure 1C] This is a cross-sectional substrate segment showing modification of the overcoat according to an embodiment of the present disclosure. [Figure 1D] This is a cross-sectional substrate segment showing the development result according to an embodiment of the present disclosure. [Figure 1E] This is a cross-sectional substrate segment showing a developing factor according to an embodiment of the present disclosure. [Figure 2A] This is a cross-sectional substrate segment showing a substrate exhibiting a relief pattern, according to an embodiment of the present disclosure. [Figure 2B] This is a cross-sectional substrate segment showing the deposition of material on a relief pattern according to an embodiment of the present disclosure. [Figure 2C] This is a cross-sectional substrate segment showing acid diffusion according to an embodiment of the present disclosure. [Figure 2D] This is a cross-sectional substrate segment showing the development result according to an embodiment of the present disclosure. [Figure 3A] This is a cross-sectional substrate segment showing a single polymer overcoat according to an embodiment of the present disclosure. [Figure 3B] This is a cross-sectional substrate segment showing a recessed single polymer overcoat according to an embodiment of the present disclosure. [Figure 4A] This is a cross-sectional substrate segment showing a polymer bilayer film system according to an embodiment of the present disclosure. [Figure 4B] This is a cross-sectional substrate segment showing a recessed polymer bilayer film system according to an embodiment of the present disclosure. [Figure 5] This is an oblique view substrate segment showing a vapor-deposited polymer bilayer film system according to an embodiment of the present disclosure. [Figure 6] This is a flowchart of a method for forming a pattern on a substrate according to an embodiment of the present disclosure. [Modes for carrying out the invention]
[0013] The following disclosure provides various embodiments or examples for implementing various features of the subject matter presented. For the sake of brevity, specific examples of components and configurations are described below. Naturally, these are merely examples and are not intended to be limiting. For example, the formation of a first feature above or on a second feature in the following description may include embodiments in which the first and second features are formed in direct contact, or it may include embodiments in which an additional feature is formed between the first and second features so that they are not in direct contact. In addition, the disclosure may repeat reference numbers and / or letters in various embodiments. This repetition is for the sake of brevity and clarity and does not in itself refer to the relationships between the various embodiments and / or configurations discussed. Furthermore, for the sake of brevity, this specification may use spatially relative terms such as “top,” “bottom,” “below,” “downward,” “lower,” “above,” and “upper” to describe the relationship of one element or feature to another, as shown in the figures. Spatially relative terminology is intended to encompass different orientations of the device in use or operation, in addition to the orientation shown in the figure. The device may be in other orientations (rotated 90 degrees, or otherwise), and spatially relative descriptors used herein may be interpreted accordingly.
[0014] The order in which the different steps described herein are presented is for the purpose of clarity. In general, these steps can be performed in any suitable order. Furthermore, different features, techniques, structures, etc., described herein may be referred to in different places within this disclosure, but each concept can be performed independently or in combination with others. Therefore, the present invention can be embodied and explored in many different ways.
[0015] Due to continuous miniaturization, an improvement in pattern formation resolution is required. One approach is to utilize spacer technology that defines sub-resolution line features via atomic layer deposition (ALD). However, when an opposite tone feature is desired, using the spacer technique can be complex and costly because it involves overcoating with another material, chemical mechanical planarization (CMP), and reactive ion etching (RIE) to dig out the spacer material and leave narrow trenches, which is one issue.
[0016] An anti-spacer is a self-aligned technique that defines a minimum line width (CD) using the diffusion length of reactive species and forms narrow trenches. By spatially controlling the reactive species through exposure through a mask, narrow slot contacts can be formed instead of narrow trenches. Instead of spatial control, the reactive species can be uniformly controlled across the wafer by the decomposition of a thermal acid generator (TAG) through a baking process. The corresponding CD can be adjusted by changing the molecular weight of the reactive species, the molecular structure of the reactive species, as well as the baking temperature and baking time. Furthermore, the CD can be controlled by the composition of the material through which the reactive species diffuses. The polarity of the components within the resin (the material through which the reactive species diffuses) can affect the acid diffusivity and the activation energy of the reactive species-sensitive components of the material, which is an additional means to control the process. These techniques can achieve narrow slot contact features with dimensions beyond advanced lithography capabilities. However, the process can include a freezing step. The freezing step can be a process that invalidates the possibility of solubility shift of the layer having the acid generator. However, the freezing process may induce defects or errors and may reduce throughput.
[0017] The aforementioned anti-spacer flow uses a thermal freezing process, in which the deprotected photoresist mandrel is inhibited from dissolving in an aqueous developer used to remove the deprotected (or de-crosslinked or otherwise solubility-altered) overcoat and expose the anti-spacer features. Incorporating a thermal freezing function into the photoresist can be challenging due to the stringent requirements for high-volume production and the reactive environment of the polymer resin.
[0018] To achieve this objective, U.S. Patent Application No. 63 / 135,217, "Freeze-less Anti-spacer Formation by Contrast Selectivity," describes a technique for forming sub-resolution anti-spacer features without the need for thermal freezing, i.e., a "freeze-less" anti-spacer method, which is hereby incorporated by reference in its entirety. What is described therein is a method for forming sub-resolution anti-spacer features that are below the deprotection threshold of the photoresist mandrel required to achieve solubility in an aqueous developer. The dissolution contrast inherent to the overcoat is paired with the photoresist mandrel such that the solubility of the overcoat can be altered to form an anti-spacer while the photoresist remains relatively or sufficiently insoluble in the developer. This process provides a means of avoiding the need for a thermal freezing step to prevent dissolution of the photoresist mandrel. Thus, no additional TAGs are required in the formulation of the mandrel.
[0019] The incorporated disclosed process improves the advantages of patterning, but this process includes the removal of the resin overcoat film. The film is the amount of filling material above the upper surface of the mandrel or the relief pattern (see below). The film can be removed to access or expose the anti-spacer features for pattern transfer or continuous pattern formation. The technique described herein enhances this anti-spacer formation method by using a self-segregating polymer mixture overcoat on a two-layer polymer system. The first polymer fills the space below the upper surface of the relief pattern, while the second polymer accumulates on top of the upper surface of the relief pattern. After the formation of the anti-spacer feature by acid diffusion, the second polymer can be easily removed with a developer without affecting the first polymer or the relief pattern.
[0021] This specification describes techniques that utilize the difference in surface energy observed in certain fluorinated polymers or polymers having long-chain alkyl functional groups to promote segregation of the surface layer (or upper film) in a bilayer polymer system. Thus, the coating film of the filler material for anti-spacer formation can be easily removed, and features formed by deprotected regions defined by diffusion distance can be accessed.
[0022] To achieve this objective, Figure 1A is a cross-sectional substrate segment showing a substrate 105 including a relief pattern 110 according to an embodiment of the present disclosure. In one embodiment, the relief pattern 110 can be formed on the surface of the substrate 105. For example, a photolithography process can be used to image and develop a layer of photoresist material onto the relief pattern 110. The relief pattern 110 can, for example, yield a mandrel 110a after development. Multiple mandrels 110a can also form the relief pattern 110 depending on the desired final features. In particular, the mandrel 110a may include width and height, and the height of the mandrel 110a can be defined by the distance measured from the surface of the substrate 105 to the top of the mandrel 110a.
[0023] Figure 1B is a cross-sectional substrate segment showing the deposition of material on a relief pattern 110 according to an embodiment of the present disclosure. In one embodiment, the overcoat 115a may be deposited on the relief pattern 110, for example, via a spin coating process. Other non-limiting examples of coating processes include, in particular, dip coating, flow coating, spray coating, etc. The deposited material may be, for example, a resin or polymer 115. In particular, an excess of deposited resin / polymer 115 may result in some amount of resin / polymer 115 being coated onto the top of the mandrel 110a. This excess can be defined as a coating film. It may be necessary to remove the coating film in order to expose the top of the mandrel 110a for further processing. For example, a CMP process can be used to physically remove the coating film of the overcoat 115a and flatten the overcoat 115a. However, processes such as CMP may not be able to achieve the removal of the overcoat 115a material between the mandrels 110a without reducing the overall height of the relief pattern 110.
[0024] Figure 1C shows a cross-sectional substrate segment illustrating the modification of the overcoat 115a according to an embodiment of the present disclosure. In one embodiment, the relief pattern 110 material may contain an acid that diffuses from the relief pattern 110 into the surrounding overcoat 115a to form a soluble region 120. That is, the acid can modify the resin / polymer 115 and cause a solubility shift. In particular, this diffusion distance may not completely change the solubility of the coating film on the upper surface of the mandrel 110a, depending on the formulation of the polymer mixture. Therefore, an extra process step may be performed to remove this insoluble coating film before accessing the anti-spacer narrow opening (trench) such as the CMP. Even if the overcoat 115a has partial solubility in a given developer, this may still hinder complete spacer formation. Increasing the solubility of the overcoat 115a may result in changes to the uniformity of trenches and CDs across the wafer (substrate 105) that are greater than desired. This may also depend on the unevenness of the substrate 105 and the dimensions of the object being accessed.
[0025] Figure 1D shows a cross-sectional substrate segment illustrating the development result according to an embodiment of the present disclosure. In one embodiment, the developer can expose the soluble region 120 and then remove the soluble region 120 of the overcoat 115a. As shown in Figure 1D, the narrow opening or anti-spacer can be defined by the diffusion distance of the acid, which results in a solubility shift of the resin / polymer 115.
[0026] Figure 1E shows a cross-sectional substrate segment illustrating development factors according to an embodiment of the present disclosure. In one embodiment, the height of the coating film and the time taken to remove the anti-spacer trench can define the development time. Thus, excessive development time widens the anti-spacer trench, while a lower dissolution rate can provide a larger process window. As shown, the height of the mandrel 110a is not the same as the height of the remaining overcoat 115a. In particular, a two-layer overcoat can help improve the overall uniformity of the wafer compared to a single polymer overcoat in an anti-spacer process flow.
[0027] This specification describes a method for forming antispace features by pattern formation on a substrate, wherein the step of removing the coating film by a self-segregating polymer mixture overcoat on a two-layer polymer system is facilitated.
[0028] To achieve this objective, Figure 2A is a cross-sectional substrate segment showing a substrate 105 including a relief pattern 110 according to an embodiment of the present disclosure. In one embodiment, a layer of photoresist can be deposited onto the relief pattern 110, imaged, and developed, as described previously.
[0029] Figure 2B is a cross-sectional substrate segment showing the deposition of a material on a relief pattern 110 according to an embodiment of the present disclosure. In one embodiment, the overcoat 115a may be deposited on the relief pattern 110, for example, via a spin coating process. Other non-limiting examples of coating processes include, in particular, dip coating, flow coating, spray coating, etc. Here, the deposition material may be, for example, a resin or polymer mixture. The polymer mixture may include, for example, a resin / polymer 115 as a first resin / polymer in the mixture and a high-solubility resin / polymer 125 as a second resin / polymer. Non-limiting examples of the high-solubility resin / polymer 125 include, in particular, HFIP-M, MA-MIB-HFA, MA-BTHB-OH, MA-3,5-HFA-CHOH, MA-BTHB-NB, MA-EATf, and MA-DM-EATf. Non-limiting examples of the resin / polymer 115 include any type of methacrylate or phenolic polymer having reverse solubility with respect to the mandrel 110a material. The overcoat 115 can not only fill the openings defined by the relief pattern 110, but can also cover the relief pattern 110. In particular, due to the excess of the deposited polymer mixture, the coating film can also cover the top of the mandrel 110a.
[0030] In one embodiment, the polymer mixture may be configured to self-segregate or self-assemble. For example, the polymer mixture may self-segregate with respect to gravity or perpendicular to the plane of the surface of the substrate 105. Self-segregation may occur after deposition without activation, or an activation step may be used depending on the composition of the polymer mixture. For example, a bake step may be used for thermal activation. As a result of self-segregation, a bilayer or two-layer film is obtained. Figure 2B shows a bilayer film after self-segregation, including a resin / polymer 115 film placed below a high-solubility resin / polymer 125 film. The composition of each film may have different properties. For example, the lower resin / polymer 115 film may be configured to provide good etching resistance. For example, the lower resin / polymer 115 film may have very low solubility in TMAH, or may not dissolve at all, unless ester protecting groups are present and deprotection occurs in the presence of an acid. Conversely, the upper high-solubility resin / polymer 125 film may have very high solubility in TMAH, for example. The lower resin / polymer 115 film can also be configured to change its solubility when the threshold for acid or other agents is lower compared to the photoresist material. Depending on the application and the material selected for a given concentration in the formulation, the upper high-solubility resin / polymer 125 film can achieve polymer segregation of 10-30 angstroms or more in situ.
[0031] In particular, in one embodiment, the relative amounts of the first polymer and the second polymer (e.g., resin / polymer 115 and high-solubility resin / polymer 125) may be configured such that there is enough material for the second polymer to constitute a coating area. The second polymer film may even extend below the upper surface of the mandrel 110a of the relief pattern 110. The second polymer film or upper polymer layer may be configured differently from the first polymer layer. The second polymer layer may be configured to dissolve in a given developer or solvent without requiring the agent to shift its solubility. Thus, the formulation of the polymer mixture facilitates the removal of the upper film or coating, thereby exposing a portion of the relief pattern 110 and optionally the lower resin / polymer 115 film.
[0032] Figure 2C shows a cross-sectional substrate segment exhibiting acid diffusion according to an embodiment of the present disclosure. In one embodiment, the upper segregated high-solubility resin / polymer 125 can be designed to have a relatively high dissolution rate in a given developer. This allows for very rapid removal of the coating to expose the anti-spacer region. After acid diffusion to form the soluble region 120, and subsequent deprotection, the anti-spacer region may also be soluble in a given developer. The acid diffusion length or distance can be precisely controlled by bake time, temperature, and other factors. By incorporating the high-solubility resin / polymer 125 at the top of a two-layer arrangement of the overcoat 115a, the need for the remaining polymer to have a specific dissolution rate in the developer can be eliminated, thus making it easier to match the etching selectivity and platform type with the polymer of the first lower film.
[0033] Removing the coating film may allow access to the anti-spacer region indicated by the arrow in Figure 2C. The high-solubility resin / polymer 125 can develop the anti-spacer using a specific developer dissolution rate while maintaining the desired aspect ratio of the formed lines. Another property of the lower resin / polymer 115 film may be different etching selectivity. To optimize etching transfer to the lower layer, it would be preferable that the etching selectivity of the lower resin / polymer 115 film and the mandrel 110a material be similar. Furthermore, in one embodiment, the high-solubility resin / polymer 125 may not require etching selectivity. To mitigate some of the challenges of lower film selectivity, a small amount of blended polymer can be used in the upper high-solubility resin / polymer 125 film. The blended polymer can be selected to be chemically different from the main polymer, and the surface energy of the blended polymer may allow segregation at the top of the film during coating, such as spin coating. The blended polymer may also have high developer solubility without requiring etching selectivity. Segregating a polymer film to form a monolayer as a topcoat for 193 nm immersion lithography not only yields an extremely thin film, but also allows for the formation of bulk heterojunctions for exciton separation in photovoltaic devices. In the embodiments described herein, a thick layer of high-solubility resin / polymer 125 can be migrated to the surface with a thickness similar to that of the coating film for the underlying resin / polymer 115 film formulation.
[0034] Figure 2D is a cross-sectional substrate segment showing the development result according to an embodiment of the present disclosure. In one embodiment, by having a higher developer dissolution rate than the upper high-solubility resin / polymer 125 film, it is possible to expose the region of the lower resin / polymer 115 film that has reacted with the diffused acid to form a developer-soluble anti-spacer region 120. The polymer remaining in the lower film does not require intrinsic or unexposed developer solubility, and attention can be focused on other properties such as etching selectivity. Another advantage of the main polymer in the lower resin / polymer 115 film not having developer solubility is that it improves the overall uniformity of the wafer. By having a two-layer polymer film system in which the upper developer-soluble high-solubility resin / polymer 125 covers slightly more than the coating portion of the overcoat 115a, the overall non-uniformity of the wafer can be essentially self-corrected to some extent. After the upper film is removed, the soluble anti-spacer can also be removed.
[0035] Other process flow steps described herein can be similar to those in a rate-selective flow process for antispacer formation, and no additional steps are required. A first resist containing an additional acid source can be coated and imaged. A second formulation containing a polymer bilayer system can be coated over the first layer image. This formulation can be coated from a solvent that does not dissolve the first layer pattern and may, but is not limited to, MIBC (methyl isobutyl carbitol). The second formulation may optionally contain a solvent that promotes segregation of the two polymers present. The low surface energy polymer may contain fluorinated moieties or long-chain alkyl functionalities to promote a surface energy difference. The low surface energy polymer may also contain acidic functional groups to promote efficient dissolution in the developer. Promoting segregation on uneven surfaces to form a coating film results in the improvements described herein. The lower main polymer can be any polymer with similar chemical properties to the pattern resist of the first layer, preferably having functional groups that promote similar etching selectivity. The main polymer may contain a switching component that deprotects (changes the solubility of) the first layer polymer at a lower activation energy. The new solubility region can be soluble in solvents that do not dissolve the first layer pattern.
[0036] In one embodiment, after vapor deposition of a polymer bilayer film, a bake step is performed to generate and diffuse an acid into the underlying polymer, and the solubility of the main polymer can be switched in a deprotection step. In a subsequent development step, the coating layer with a high dissolution rate and the areas deprotected by acid diffusion baking can be removed. After the development step, trenches and lines are formed from the underlying film. Here, a new pattern with smaller trenches can be transferred to the underlying layer.
[0037] Advantageously, the polymer bilayer film system described herein improves overall wafer uniformity compared to a single polymer overcoat in an anti-spacer process flow. In a polymer bilayer system, the coating film can be made of a different material from the sidewall, and the lower polymer of the polymer bilayer system does not require solubility in, for example, TMAH. As can be understood, various polymers and compositions can be selected to form a polymer bilayer system. Depending on the selected polymer and solvent system, the upper layer can have various heights. Thus, the height of a given coating film and the time it takes to remove the anti-spacer trench can define the corresponding development time. Increasing the development time can widen the anti-spacer trench, while a lower dissolution rate can provide a larger process window.
[0038] To achieve this objective, Figure 3A is a cross-sectional substrate segment showing a single polymer overcoat according to an embodiment of the present disclosure. Figure 3B is a cross-sectional substrate segment showing a recessed single polymer overcoat according to an embodiment of the present disclosure. In one embodiment, there are many manufacturing steps where it is desired to partially fill a trench or opening. Some processes may involve depositing a single polymer overcoat 115a and then performing an etching step to remove the coating and recess the material. This type of etching may lack an etching stop layer, and therefore the amount of recess is estimated using etching time, which can be poorly controllable. Atomic layer etching can be used, but this can increase costs and decrease throughput.
[0039] Thus, Figure 4A is a cross-sectional substrate segment showing a polymer bilayer film system according to an embodiment of the present disclosure. Figure 4B is a cross-sectional substrate segment showing a recessed polymer bilayer film system according to an embodiment of the present disclosure. In one embodiment, the polymer mixture can be selected to be soluble in different developers and self-segregate or self-assemble into at least two layers. The upper film (highly soluble resin / polymer 125) can fill the coating area and part of the openings. The upper film can be removed using a specific solvent that does not dissolve the lower film (resin / polymer 115) or has at least a significantly slow dissolution rate, so that the upper film can be removed while leaving the lower film in place.
[0040] As can be understood, there may be several applications where filling recessed trenches is desired. As a non-limiting example, one application involves forming recesses with spin-on glass. Figure 5 is an oblique view of a substrate segment showing a deposited polymer bilayer film system according to an embodiment of the present disclosure. On the left side of Figure 5, a precise recess between spacers is desired. The polymer mixture can be deposited onto a substrate having a specific feature / opening. The polymer mixture can segregate to a precise depth in the trench and then be removed by a spin-on solvent rinse. One advantage of this bilayer recess is its implementation into track tools (coater-developer tools) to improve throughput. In some recess applications, the polymer bilayer film system can be a defined alternative to bottom growth, which is independent of substrate or sidewall selectivity. Note that bilayer segregation as described herein is not limited to soft materials, and any type of spin-on material mixture that supports self-segregation can be used.
[0041] In summary, the two-layer overcoat film enables a high-throughput method that allows for the formation of a coating of controlled thickness, which can then be removed to create a flat surface or precisely adjusted recesses. During anti-spacer coating, the overcoat polymer segregating on the surface has high developer solubility. The development process allows for the rapid removal of the upper polymer forming the coating, thereby exposing the lower deprotected polymer and forming a trench. The protected acid-unstable overcoat polymer at the bottom of the two layers does not require developer solubility, thereby improving the uniformity of CD across the wafer and enabling enhanced polymer functionality.
[0042] Figure 6 is a flowchart of a method 600 for forming a pattern on a substrate according to an embodiment of the present disclosure.
[0043] Step 605 is to deposit a first layer of photoresist onto the substrate.
[0044] Step 610 is to form a relief pattern from a first layer of photoresist, the first layer of photoresist comprising a first solubility shift agent and a second solubility shift agent, the photoresist being sensitive to the first solubility shift agent and the second solubility shift agent, and the relief pattern is formed by activating the first solubility shift agent using a chemical line of a certain pattern and developing the first layer of photoresist.
[0045] Step 615 is to deposit a resin or polymer mixture onto a relief structure, wherein the resin / polymer mixture fills the openings defined by the relief pattern and covers the relief structure, the area above the top surface of the relief structure is a coating area, the resin / polymer mixture comprises a first resin / polymer and a second resin / polymer, the resin / polymer mixture is configured to self-segregate with respect to gravity so that a first film and a second film are formed from the resin / polymer mixture, the first film containing the first resin / polymer is formed below the second film containing the second resin / polymer, the first film and the second film are formed such that the second film fills the coating area, the first film is sensitive to a second solubility shift agent and has a sensitivity threshold lower than the sensitivity threshold of the photoresist, and the second film is soluble in a first developer.
[0046] Step 620 involves activating a second solubility shift agent and diffusing the second solubility shift agent from the relief structure to the first film to a predetermined diffusion length, wherein the second solubility shift agent is sufficiently activated to satisfy the sensitivity threshold of the first film without satisfying the sensitivity threshold of the photoresist, and the diffusion region formed on the first film becomes soluble in the first developer, while the photoresist remains insoluble in the first developer.
[0047] Step 625 is to develop the substrate to remove the soluble diffusion regions of the second film and the first film.
[0048] A method for forming a pattern on a substrate is to form a relief pattern on the substrate from a first layer of photoresist on the substrate, wherein the first layer of photoresist comprises a first solubility shift agent and a second solubility shift agent, the photoresist is sensitive to the first solubility shift agent and the second solubility shift agent, and the relief pattern is formed by activating the first solubility shift agent using a chemical line of a pattern and developing the first layer of photoresist; and to deposit a polymer mixture onto the relief structure, wherein the polymer mixture fills the openings defined by the relief pattern, covers the relief structure, and the region above the top surface of the relief structure is a coating region, the polymer mixture comprises a first polymer and a second polymer, and the polymer mixture is configured to self-segregate with respect to gravity so that a first film and a second film are formed from the polymer mixture, A first film containing a polymer is formed beneath a second film containing a second polymer, and the first and second films are formed such that the second film fills a coating region, the first film is sensitive to a second solubility shift agent and has a sensitivity threshold lower than that of the photoresist, and the second film is soluble in a first developer; the second solubility shift agent is activated and diffused from the relief structure to the first film to a predetermined diffusion length, wherein the second solubility shift agent is activated sufficiently to satisfy the sensitivity threshold of the first film without satisfying the sensitivity threshold of the photoresist, the diffusion region formed on the first film becomes soluble in the first developer, while the photoresist remains insoluble in the first developer; and the substrate is developed to remove the soluble diffusion region of the second film and the first film.
[0049] In one embodiment, the polymer mixture is deposited by spin coating deposition.
[0050] In one embodiment, the polymer mixture undergoes autosegregation when deposited onto the substrate.
[0051] In one embodiment, the second film extends below the upper surface of the relief structure during self-segregation.
[0052] In one embodiment, the polymer mixture self-segregates in response to heat, and the method further includes depositing the polymer mixture onto a relief structure and then performing a thermal bake.
[0053] In one embodiment, developing the substrate further includes developing the substrate with a first developer to remove the second film and the soluble diffusion regions of the first film.
[0054] In one embodiment, the second film is soluble in the second developer, and developing the substrate further includes developing the substrate with the second developer to remove the second film, and then developing the substrate with the first developer to remove the soluble diffusion region of the first film.
[0055] In one embodiment, the second film is removed after activating the second solubility shift agent.
[0056] In one embodiment, the second film is removed before the second solubility shift agent is activated.
[0057] In one embodiment, the material of the second polymer includes HFIP-M, MA-MIB-HFA, MA-BTHB-OH, MA-3,5-HFA-CHOH, MA-BTHB-NB, MA-EATf, and MA-DM-EATf.
[0058] A method for forming a pattern on a substrate is to form a relief pattern on the substrate from a first layer of photoresist on the substrate, wherein the first layer of photoresist comprises a first solubility shift agent and a second solubility shift agent, the photoresist is sensitive to the first solubility shift agent and the second solubility shift agent, and the relief pattern is formed by activating the first solubility shift agent using a chemical line of a pattern and developing the first layer of photoresist; and to deposit a resin overcoat onto the relief structure, wherein the resin overcoat fills the openings defined by the relief pattern and covers the relief structure, the region above the top surface of the relief structure is a coating region, the resin overcoat has a resin mixture comprising a first resin and a second resin, and the resin overcoat is configured to self-segregate with respect to gravity so that a first film and a second film are formed from the resin overcoat. The present invention relates to a method comprising: a first film containing a first resin being formed beneath a second film containing a second resin, the first and second films being formed such that the second film fills a coating region, the first film being sensitive to a second solubility shift agent and having a sensitivity threshold lower than that of the photoresist, and the second film being soluble in a first developer; activating the second solubility shift agent and diffusing it from the relief structure to the first film to a predetermined diffusion length, wherein the second solubility shift agent is sufficiently activated to satisfy the sensitivity threshold of the first film without satisfying the sensitivity threshold of the photoresist, the diffusion region formed on the first film becoming soluble in the first developer, while the photoresist remains insoluble in the first developer; and developing the substrate to remove the soluble diffusion region of the second film and the first film.
[0059] In one embodiment.
[0060] In one embodiment, the resin overcoat is deposited by a spin coating deposition method.
[0061] In one embodiment, the resin overcoat undergoes self-segregation when deposited onto the substrate.
[0062] In one embodiment, the second film extends below the upper surface of the relief structure during self-segregation.
[0063] In one embodiment, the resin overcoat self-segregates in response to heat, and the method further includes depositing the resin overcoat onto a relief structure and then performing a thermal bake.
[0064] In one embodiment, developing the substrate further includes developing the substrate with a first developer to remove the second film and the soluble diffusion regions of the first film.
[0065] In one embodiment, the second film is soluble in the second developer, and developing the substrate further includes developing the substrate with the second developer to remove the second film, and then developing the substrate with the first developer to remove the soluble diffusion region of the first film.
[0066] In one embodiment, the second film is removed after activating the second solubility shift agent.
[0067] In one embodiment, the second film is removed before the second solubility shift agent is activated.
[0068] A method for patterning a substrate includes: receiving a substrate having features defining partially filled openings; depositing a polymer mixture onto the substrate, wherein the polymer mixture fills the openings defined by the features, covers the features, and the area above the top surface of the features is a coating region, the polymer mixture comprises a first polymer and a second polymer, and the polymer mixture is configured to self-segregate with respect to gravity such that a first film and a second film are formed from the polymer mixture, the first film containing the first polymer being formed below the second film containing the second polymer, the first and second films being formed such that the first film partially fills the defined openings while the second film fills the remaining portion of the defined openings and fills the coating region, the second film being sensitive to a particular solvent while the first film is insoluble in a particular solvent; and developing the substrate with a particular solvent to remove the second film, leaving the first film in the defined openings.
[0069] In the preceding description, specific details have been provided, such as the particular geometric shape of the processing system and descriptions of the various components and processes used. However, it should be understood that the techniques described herein may be implemented in other embodiments different from these specific details, and that such details are for illustrative purposes only and not to limit the scope. Multiple embodiments disclosed herein have been described with reference to the accompanying drawings. Similarly, for illustrative purposes, certain numbers, materials, and configurations have been shown to ensure thorough understanding. However, multiple embodiments may be implemented without such specific details. Since components having substantially identical functional structures are indicated by the same reference numerals, redundant descriptions may be omitted.
[0070] To aid in understanding various embodiments, various techniques have been described as multiple operations. The order of description should not be interpreted as meaning that these operations are necessarily order-dependent. In fact, these operations do not have to be performed in the order presented. The described operations may be performed in a different order than in the described embodiments. Various additional operations may be performed in additional embodiments, and / or the described operations may be omitted.
[0071] As used herein, “substrate” or “target substrate” refers collectively to an object processed in accordance with the present invention. A substrate may include any material portion or structure of a device, in particular a semiconductor device or other electronic device, such as a base substrate structure, reticle, or layer on or superimposed on a base substrate structure, such as a thin film. Therefore, a substrate is not limited to any particular base structure, underlay, or coating layer, whether patterned or not, but rather is intended to include any such layer or base structure, and any combination of layers and / or base structures. The description may refer to specific types of substrates, but these are for illustrative purposes only.
[0072] Those skilled in the art will also understand that even with many modifications to the operation of the techniques described above, the same objectives of the present invention can still be achieved. Such modifications are intended to be included within the scope of this disclosure. Therefore, the above description of embodiments of the present invention is not intended to be limiting. Rather, limitations on embodiments of the present invention are presented in the following claims.
Claims
1. A method for forming a pattern on a substrate, A step of forming a relief pattern including a relief structure on a substrate from a first layer of photoresist on the substrate, The first layer of the photoresist comprises a first solubility shift agent and a second solubility shift agent. The relief pattern is formed by activating the first solubility shift agent using a chemical line pattern and developing the first layer of the photoresist, The step of forming a polymer mixture film on the relief structure, The polymer mixture fills the openings defined by the relief pattern and coats the relief structure. The region above the upper surface of the aforementioned relief structure is an overburden region. The polymer mixture comprises a first polymer and a second polymer. The polymer mixture is configured to self-segregate with respect to gravity so that a first thin film and a second thin film are formed from the polymer mixture. The first thin film containing the first polymer is formed below the second thin film containing the second polymer, The first thin film and the second thin film are formed such that the second thin film fills the coating region. When the second solubility shift agent is activated, the first thin film exhibits higher reactivity to the second solubility shift agent compared to the photoresist. The first thin film is insoluble in the first developer, The second thin film is soluble in the first developer, step and The steps include activating the second solubility shift agent and diffusing the second solubility shift agent from the relief structure to the first thin film with a predetermined diffusion length, The diffusion region formed on the first thin film by reaction with the second solubility shift agent becomes soluble in the first developer, while the photoresist remains insoluble in the first developer. The steps include developing the substrate to remove the soluble diffusion regions of the second thin film and the first thin film, Methods that include...
2. The method according to claim 1, wherein the polymer mixture is formed by a spin coating method.
3. The method according to claim 1, wherein the polymer mixture undergoes self-segregation when a film is formed on the substrate.
4. The method according to claim 3, wherein the second thin film extends below the upper surface of the relief structure during self-segregation.
5. The aforementioned polymer mixture undergoes autosegregation in response to heat, The method according to claim 3, further comprising the step of forming the polymer mixture on the relief structure and then performing a thermal bake.
6. The method according to claim 1, wherein the step of developing the substrate further includes developing the substrate with the first developer to remove the second thin film and the soluble diffusion region of the first thin film.
7. The second thin film is soluble in the second developer, The method according to claim 1, wherein the step of developing the substrate further includes the step of developing the substrate with the second developer to remove the second thin film, prior to the step of developing the substrate with the first developer to remove the soluble diffusion region of the first thin film.
8. The method according to claim 7, wherein the second thin film is removed after activating the second solubility shift agent.
9. The method according to claim 7, wherein the second thin film is removed before activating the second solubility shift agent.
10. The method according to claim 1, wherein the material of the second polymer comprises HFIP-M, MA-MIB-HFA, MA-BTHB-OH, MA-3,5-HFA-CHOH, MA-BTHB-NB, MA-EATf, and MA-DM-EATf.
11. A method for forming a pattern on a substrate, A step of forming a relief pattern including a relief structure on a substrate from a first layer of photoresist on the substrate, The first layer of the photoresist comprises a first solubility shift agent and a second solubility shift agent. The relief pattern is formed by activating the first solubility shift agent using a chemical line pattern and developing the first layer of the photoresist, The step of forming a resin overcoat on the relief structure, The resin overcoat fills the openings defined by the relief pattern and covers the relief structure. The region above the upper surface of the relief structure is a coating region. The resin overcoat comprises a resin mixture containing a first resin and a second resin. The resin overcoat is configured to self-segregate with respect to gravity so that a first thin film and a second thin film are formed from the resin overcoat. The first thin film containing the first resin is formed below the second thin film containing the second resin, The first thin film and the second thin film are formed such that the second thin film fills the coating region. When the second solubility shift agent is activated, the first thin film exhibits higher reactivity to the second solubility shift agent compared to the photoresist. The first thin film is insoluble in the first developer, The second thin film is soluble in the first developer, step and The steps include activating the second solubility shift agent and diffusing the second solubility shift agent from the relief structure to the first thin film with a predetermined diffusion length, The diffusion region formed on the first thin film by reaction with the second solubility shift agent becomes soluble in the first developer, while the photoresist remains insoluble in the first developer. The steps include developing the substrate to remove the soluble diffusion regions of the second thin film and the first thin film, Methods that include...
12. The method according to claim 11, wherein the resin overcoat is formed by a spin coating method.
13. The method according to claim 11, wherein the resin overcoat self-segregates when it is formed on the substrate.
14. The method according to claim 13, wherein the second thin film extends below the upper surface of the relief structure during self-segregation.
15. The aforementioned resin overcoat undergoes self-segregation in response to heat, The method according to claim 13, further comprising the step of forming the resin overcoat on the relief structure and then performing a thermal bake.
16. The method according to claim 11, wherein the step of developing the substrate further includes developing the substrate with the first developer to remove the second thin film and the soluble diffusion region of the first thin film.
17. The second thin film is soluble in the second developer, The method according to claim 11, wherein the step of developing the substrate further includes the step of developing the substrate with the second developer to remove the second thin film, prior to the step of developing the substrate with the first developer to remove the soluble diffusion region of the first thin film.
18. The method according to claim 17, wherein the second thin film is removed after activating the second solubility shift agent.
19. The method according to claim 17, wherein the second thin film is removed before activating the second solubility shift agent.
20. A method for forming a pattern on a substrate, A step of receiving a substrate having a feature portion that defines an opening to be partially filled, The step of forming a polymer mixture film on the substrate, The polymer mixture fills the opening defined by the feature portion and covers the feature portion. The region above the upper surface of the aforementioned feature portion is a coating region. The polymer mixture comprises a first polymer and a second polymer. The polymer mixture is configured to self-segregate with respect to gravity so that a first thin film and a second thin film are formed from the polymer mixture. The first thin film containing the first polymer is formed below the second thin film containing the second polymer, The first thin film and the second thin film are formed such that the first thin film partially fills the defined opening, while the second thin film fills the remaining portion of the defined opening, thereby filling the coating region. The second thin film is soluble in the first solvent, while the first thin film is insoluble in the first solvent, step and The step of developing the substrate using the first solvent to remove the second thin film, The first thin film has a step remaining in the defined opening, Methods that include...