An underlayer adhesive composition and its use in semiconductor manufacturing processes

Abstract

Embodiments of the present application provide a primer composition, the primer composition comprising: an alkali-soluble resin; a water-soluble polymer, the water-soluble polymer having a dissolution rate in a developer greater than a dissolution rate of the alkali-soluble resin in the developer; a crosslinking agent, the crosslinking agent crosslinking the alkali-soluble resin and the water-soluble polymer; an organic solvent capable of dissolving both the alkali-soluble resin and the water-soluble polymer; an additive; wherein the primer composition does not contain a photosensitive agent. Embodiments of the present application also provide a bilayer system and applications of the bilayer system in a semiconductor manufacturing process. The technical solution of the present application can simplify the process steps of pattern formation and transfer in the bilayer photoresist process, and can accurately control the lithography window by controlling the crosslinking degree of the primer composition and the development time.

Description

Technical Field

[0001] This application relates to the field of semiconductor technology, and more specifically to an underlayer adhesive composition and its application in semiconductor manufacturing processes. Background Technology

[0002] In semiconductor manufacturing processes, metals are typically used as conductors to connect functional units within devices. Some metals or processes cannot be patterned by etching; these metals usually require vapor deposition to transfer the pattern. This type of process uses photoresist capable of forming an inverted trapezoidal shape. During vapor deposition, the metal deposited on the photoresist is detached along with the photoresist during the stripping process, thus forming the desired pattern. However, when depositing thicker metals, the metal tends to adhere to the sidewalls of the photoresist. In this case, the metal deposited at the top of the photoresist can connect with the metal deposited in the unremoved areas through the sidewalls, making it impossible to remove them together during photoresist stripping, leading to short circuits and other problems.

[0003] Existing technologies use a double-layer photoresist structure to form an undercut on the bottom layer to solve the aforementioned short circuit problem. However, in actual production, the bottom layer of the double-layer photoresist structure also has certain photosensitive characteristics, resulting in a mismatch between the positive or negative photoresist masks of the bottom and top layers. Furthermore, the double exposure process for overlay requires high overlay precision from the exposure equipment. Summary of the Invention

[0004] To address the aforementioned problems in the prior art, embodiments of this application propose a base resist composition, providing a two-layer system that requires only one photolithography step, and offering the application of the two-layer system in semiconductor manufacturing processes. This simplifies the process steps of pattern formation and transfer in the two-layer photoresist process, and allows for precise control of the photolithography window by controlling the degree of crosslinking and development time of the base resist composition.

[0005] According to one aspect of this application, a base coat composition is provided, comprising: an alkali-soluble resin; a water-soluble polymer, wherein the water-soluble polymer has a dissolution rate in a developer solution greater than the dissolution rate of the alkali-soluble resin in a developer solution; a crosslinking agent for crosslinking the alkali-soluble resin and the water-soluble polymer; an organic solvent capable of simultaneously dissolving the alkali-soluble resin and the water-soluble polymer; and additives; wherein the base coat composition does not contain a photosensitizer.

[0006] In some embodiments, the mass ratio of alkali-soluble resin to water-soluble polymer is 3-20:1, preferably 5-15:1.

[0007] In some embodiments, the dissolution rate of the alkali-soluble resin in the developer is less than 300 Å / s, and the dissolution rate of the water-soluble polymer in the developer is greater than 1000 Å / s; preferably, the dissolution rate of the alkali-soluble resin in the developer is between 50 and 150 Å / s, and the dissolution rate of the water-soluble polymer in the developer is greater than 2000 Å / s.

[0008] In some embodiments, the weight-average molecular weight of the alkali-soluble resin is between 1,000 and 50,000, and the weight-average molecular weight of the water-soluble polymer is between 1,000 and 100,000. Preferably, the weight-average molecular weight of the alkali-soluble resin is between 10,000 and 50,000, and the weight-average molecular weight of the water-soluble polymer is between 5,000 and 50,000.

[0009] In some embodiments, the alkali-soluble resin is one or more selected from phenolic resin, acrylic resin, methacrylic resin, hydroxystyrene resin, polyimide resin, and silicone resin.

[0010] In some embodiments, the water-soluble polymer is one or more of polyvinylpyrrolidone, polyvinyl alcohol, polyethylene glycol, polyether polyol, polyacrylic acid, polyethyleneimine, polyethyleneamine, polyallylamine, alkyd resin, and sulfonamide resin.

[0011] In some embodiments, the crosslinking agent is one or more of melamine resin, epoxy monomer having at least two epoxy groups, and epoxy phenolic resin.

[0012] In some embodiments, the organic solvent is one or more of benzyl alcohol, benzyl alcohol, γ-butyrolactone, ethyl lactate, propylene glycol monomethyl ether, ethylene glycol methyl ether, ethylene glycol ethyl ether, ethylene glycol butyl ether, diethylene glycol dimethyl ether, N-methylpyrrolidone, N,N-dimethylacetamide, and N,N-dimethylformamide.

[0013] In some embodiments, based on the mass of the undercoat composition as 100%, the mass fraction of the alkali-soluble resin is 5%-40%, the mass fraction of the water-soluble polymer is 0.01%-10%, the mass fraction of the crosslinking agent is 0.01%-10%, the mass fraction of the additive is 0.01%-5%, and the mass fraction of the organic solvent is 40%-90%.

[0014] According to another aspect of this application, a two-layer system is provided, comprising a top photoresist layer formed of a photoresist composition and a bottom resist film layer formed of the aforementioned bottom resist composition, wherein the top photoresist layer is located on the bottom resist film layer, and wherein the water-soluble polymer is insoluble in the organic solvent in the photoresist composition.

[0015] According to another aspect of this application, an application of a bilayer system in a semiconductor manufacturing process is provided, including exposing and developing the bilayer system.

[0016] The underlying adhesive composition of this application can be used in conjunction with the photoresist composition to form a two-layer system. The underlying adhesive composition is used to form the undercut underlying adhesive film layer (i.e., the undercut sacrificial layer). After the underlying adhesive composition forms the undercut film layer, it can resist the solvent of the photoresist composition. The undercut film layer does not mix with the top photoresist layer and has good solubility in the developer. The undercut window can be precisely controlled by controlling the degree of crosslinking of the underlying adhesive composition and the development time in subsequent processes. Attached Figure Description

[0017] To more clearly illustrate the embodiments of this application, the accompanying drawings used in the embodiments will be briefly described below. Obviously, the drawings described below are merely some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort. It is worth noting that, according to industry standard practice, the components are not drawn to scale and are used only for illustrative purposes. In fact, for clarity of discussion, the dimensions of the components can be arbitrarily increased or decreased.

[0018] Figures 1-6 A schematic flowchart of a semiconductor manufacturing process according to some embodiments of this application is shown.

[0019] Figure 7 A scanning electron microscope image of the morphology of a photoresist pattern after it has been formed, according to an embodiment of this application, is shown.

[0020] Figure 8 The image shown is a scanning electron microscope (SEM) image of the morphology of Comparative Example 4 after the formation of the photoresist pattern.

[0021] Figure 9 The image shown is a scanning electron microscope image of the morphology of Comparative Example 5 after the photoresist pattern has been formed. Detailed Implementation

[0022] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention. It should be understood that the technical features involved in the various embodiments of this application described below can be combined with each other as long as they do not conflict with each other.

[0023] This application provides a base coat composition comprising: an alkali-soluble resin; a water-soluble polymer, wherein the water-soluble polymer has a greater dissolution rate in the developer than the alkali-soluble resin has a greater dissolution rate in the developer; a crosslinking agent that crosslinks the alkali-soluble resin and the water-soluble polymer; an organic solvent capable of simultaneously dissolving the alkali-soluble resin and the water-soluble polymer; and additives; wherein the base coat composition does not contain a photosensitizer. The alkali-soluble resin of this application is soluble in both the organic solvent and developer of the photoresist composition and is a commonly used resin in the photoresist field. Water-soluble polymers, on the other hand, are insoluble in the organic solvent of typical photoresist compositions but soluble in the developer. Furthermore, the rate at which water-soluble polymers dissolve in the developer is greater than that of alkali-soluble resins. The bottom resist composition of this application, by limiting the addition of water-soluble polymers and crosslinking agents (alkali-soluble resins and water-soluble polymers can be crosslinked through the crosslinking agent), and by limiting the organic solvent to one that can simultaneously dissolve both alkali-soluble resins and water-soluble polymers, allows the bottom resist composition to be used in conjunction with the photoresist composition to form a bilayer system. The bottom resist composition can be used to form the undercut bottom resist film layer (i.e., the undercut sacrificial layer). After forming the bottom resist film layer, the bottom resist composition resists the solvent of the photoresist composition, does not mix with the top photoresist layer, and exhibits good solubility in the developer. The undercut window can be precisely controlled by adjusting the degree of crosslinking of the bottom resist composition and the development time in subsequent processes.

[0024] This application also provides a two-layer system comprising a top photoresist layer formed by a photoresist composition and a bottom resist film layer formed by the aforementioned bottom resist composition, wherein the top photoresist layer is located on the bottom resist film layer and the two are in direct contact, wherein the water-soluble polymer is not dissolved in the organic solvent in the photoresist composition.

[0025] It should be understood that the cross-linking of water-soluble polymers with alkali-soluble resins reduces the solubility of alkali-soluble resins in the organic solvents of the photoresist composition. This allows the bottom sacrificial layer located below to resist the organic solvents of the top photoresist layer located above, preventing the bottom and top layers from becoming miscible. In addition, due to the presence of water-soluble polymers (water-soluble polymers have a high dissolution rate in the developer, and cross-linked water-soluble polymers can still dissolve in the developer), even if cross-linking occurs, the bottom layer can still dissolve in the developer, and the dissolution rate is faster than that of the top photoresist layer. Therefore, it can be ensured that when the bottom adhesive composition and the photoresist composition are used together, the bottom layer can form an undercut, and the undercut can be precisely controlled by controlling the degree of cross-linking and the development time in subsequent processes.

[0026] In some embodiments, the mass ratio of alkali-soluble resin to water-soluble polymer is 3-20:1. If the mass of alkali-soluble resin is less than three times the mass of water-soluble polymer, the water-soluble polymer content is too high, resulting in a rapid overall development speed even after cross-linking occurs in the composition after baking. Excessive development of the underlayer can cause the upper photoresist layer to tilt or detach from the substrate. If the mass of alkali-soluble resin is greater than 20 times the mass of water-soluble polymer, the water-soluble polymer content is too low, leading to excessively long development time required to form the undercut pattern, or causing the development speeds of the upper and lower layers to be similar, thus preventing the formation of the undercut pattern. In some preferred embodiments, the mass ratio of alkali-soluble resin to water-soluble polymer is 5-15:1. The overall development speed of the composition after coating and baking is 20-300 Å / s, which is moderate and facilitates better control of forming the desired undercut pattern after exposure and development.

[0027] In some embodiments, the dissolution rate of the alkali-soluble resin in the developer is less than 300 Å / s; the dissolution rate of the water-soluble polymer in the developer is greater than 1000 Å / s. If the dissolution rate of the alkali-soluble resin in the developer is greater than 300 Å / s, the molecular weight of the alkali-soluble resin is too low, and the cross-linked composition cannot resist the solvent during the top layer photoresist spin coating process, resulting in miscibility between the upper and lower layers. After miscibility, the undercut pattern cannot be formed. If the dissolution rate of the water-soluble polymer in the developer is less than 1000 Å / s, the development speed of the cross-linked composition after baking will be too low, resulting in an excessively long development time or failure to develop. Preferably, the alkali-soluble resin has a dissolution rate in the developer between 50-150 Å / s; the water-soluble polymer has a dissolution rate in the developer greater than 2000 Å / s; and the composition can crosslink and form a polymer that can resist the solvent of the upper photoresist after spin coating and baking. The development rate of this polymer is between 20-300 Å / s, which is significantly different from the development rate of the unexposed part of the upper pattern, and can form a clear undercut pattern.

[0028] In some embodiments, the weight-average molecular weight of the alkali-soluble resin is between 1000 and 50000, and the weight-average molecular weight of the water-soluble polymer is between 1000 and 100000. When the weight-average molecular weight of the water-soluble polymer is greater than 100000, and the dissolution rate in the developer is greater than 2000 Å / s, this type of water-soluble polymer has excessively high hydrophilicity and polarity, and cannot miscibly dissolve with other components to form a homogeneous solution. When the weight-average molecular weight of the water-soluble polymer is less than 1000, the polymer formed by cross-linking after the composition is baked after spin coating cannot resist the solvent of the upper photoresist layer. Preferably, the weight average molecular weight of the alkali-soluble resin is between 10,000 and 50,000, and the weight average molecular weight of the water-soluble polymer is between 5,000 and 50,000. The solvent of the top photoresist composition is a poor solvent for the water-soluble polymer. The water-soluble polymer with a molecular weight in this range, when combined with a high molecular weight alkali-soluble resin, crosslinking agent, and additives, can form a polymer that can resist the solvent of the top photoresist composition and is soluble in the developer.

[0029] In this application, the weight-average molecular weight was determined according to the national standard GB / T 21863-2008 Gel permeation chromatography (GPC) using tetrahydrofuran as the eluent, and polystyrene standard was selected for the determination of the standard curve.

[0030] In some embodiments, the alkali-soluble resin may be one or more of phenolic resin, acrylic resin, methacrylic resin, hydroxystyrene resin, polyimide resin, and silicone resin.

[0031] In some embodiments, the water-soluble polymer may be one or more of polyvinylpyrrolidone, polyvinyl alcohol, polyethylene glycol, polyether polyol, polyacrylic acid, polyethyleneimine, polyethyleneamine, polyallylamine, alkyd resin, and sulfonamide resin.

[0032] In some embodiments, the crosslinking agent may be one or more of melamine resin, epoxy monomer having at least two epoxy groups, and epoxy phenolic resin.

[0033] More specifically, the melamine resin is a melamine resin containing ether bond substituents, and its molecular structure is shown in Formula 1: Equation 1; where R 1 R 2 R 3 R 4 R 5 R 6 Each can independently represent -H, -OH, -CH3, -CH2OH, -CH2CH2OH, -CH2OCH3, -CH2CH2OCH3, -OCH3, -OCH2CH3, R 1 -R 6The substituents contain multiple ether bonds, and the number of ether bonds is 2-6.

[0034] Preferably, the structural formula of the melamine resin containing ether bonds can be one or more of the structural formulas shown below: Compound 1 Compound 2 Compound 3 Compound 4 Compound 5 Compound 6 Compound 7 Compound 8 Compound 9 Compound 10 Compound 11 Compound 12 Compound 13 Compound 14 Compound 15 Compound 16 Compound 17.

[0035] Preferably, the structural formula of the epoxy monomer can be one or more of the structural formulas shown below: Compound 18 Compound 19 Compound 20 Compound 21 Compound 22 Compound 23 Compound 24 Compound 25 Compound 26 Compound 27 Compound 28 Compound 29 Compound 30.

[0036] Preferably, the structural formula of the epoxy phenolic resin can be one or more of the structural formulas shown below: Compound 31 Compound 32; epoxy equivalent of 100-400, preferably 150-350, and molecular weight of 500-5000, preferably 800-3000.

[0037] In some embodiments, the organic solvent of the undercoat composition may be one or more of benzyl alcohol, benzyl alcohol, γ-butyrolactone, ethyl lactate, propylene glycol monomethyl ether, ethylene glycol methyl ether, ethylene glycol ethyl ether, ethylene glycol butyl ether, diethylene glycol dimethyl ether, and N-methylpyrrolidone.

[0038] In some embodiments, the additive in the undercoat composition is a silicone-containing surfactant. Preferably, the surfactant includes a silicone ether surfactant. Preferably, the silicone ether surfactant includes any one or a combination of at least two of polyether siloxane copolymers, polyether-modified siloxane copolymers, or polyester-modified polydimethylsiloxane copolymers.

[0039] In some embodiments, based on the mass of the undercoat composition as 100%, the mass fraction of the alkali-soluble resin is 5%-40%, the mass fraction of the water-soluble polymer is 0.01%-10%, the mass fraction of the crosslinking agent is 0.01%-10%, the mass fraction of the additive is 0.01%-5%, and the mass fraction of the organic solvent is 40%-90%.

[0040] This application also provides the application of bilayer systems in semiconductor manufacturing processes, including exposure and development of bilayer systems. Figures 1-6 A schematic flow diagram of a semiconductor manufacturing process according to some embodiments of this application is shown, wherein... Figures 1-4 This illustrates a method for forming photoresist patterns in semiconductor manufacturing processes. (Reference) Figures 1-4 As shown, this application provides a method for forming a photoresist pattern, comprising the following steps: S1: uniformly coating a bottom resist composition on a substrate 10; S2: baking the bottom resist composition coated in step S1 to remove organic solvents, forming a bottom resist film layer 12; S3: uniformly coating a layer of photoresist composition, which may be a positive photoresist composition or a negative photoresist composition, on top of the bottom resist film layer baked in step S2; S4: baking the photoresist composition coated in step S3 to form a top photoresist layer 14; S5: using a photomask 16, exposing the bottom resist film layer 12 and the top photoresist layer 14 obtained in step S4 to a photolithography machine; S6: placing the exposed top photoresist layer 14' and the bottom resist film layer 12 obtained in step S5 in a developing solution (not shown) for development until the target pattern is obtained (see [reference]). Figure 4 S7: Perform hard film baking on the obtained target pattern (not shown). According to the above method, if positive photoresist is applied in step S3, the formation of the photoresist pattern is performed according to steps S1 to S7 above; if negative photoresist is applied in step S3, step S5' is added after step S5 and before step S6: the underlying resist layer and photoresist layer exposed in step S5 are exposed and then baked to solidify the photoresist layer in the exposed area.

[0041] In this process, the coating methods for steps S1 and S3 can be spin coating or slot coating; the baking temperature for step S2 can be 80~200°C, and the baking time can be 60s~300s. The baking temperature and time in step S2 affect the crosslinking reaction of the alkali-soluble resin and the water-soluble polymer under the action of the crosslinking agent. By controlling the baking temperature and baking time, the degree of crosslinking among the three can be controlled, thereby controlling the development rate of the underlying film layer in the development step, thus making it more flexible and applicable in use; the baking temperature for step S4 is 80~200°C. The baking temperature is 0~130°C, and the baking time is 60s~240s; in step S5', the exposure is performed at 90-120°C followed by baking for 60-120s; in step S6, the developer can be a tetramethylammonium hydroxide aqueous solution with a concentration range of 0.4~3.5%, or a sodium hydroxide aqueous solution with a concentration range of 0.1~1%, or a potassium hydroxide aqueous solution with a concentration range of 0.1~1%, and the developing time is 40s~300s, which can be controlled according to actual needs; in step S7, the post-baking temperature is 120-130°C, and the baking time is 60-100s to make the hardening film more complete.

[0042] In step S3, the solvent used in the photoresist composition can be one or more of the following: propylene glycol methyl ether acetate, ethyl acetate, n-butyl acetate, ethyl ethoxypropionate, methyl 3-methylpropionate, anisole, diethylene glycol diethyl ether, diethylene glycol methyl ethyl ether, diethylene glycol methyl ethyl ether, tetrahydrofuran, toluene, xylene, and cyclohexane. The solvent used in the photoresist composition is a solvent that is not easily soluble in the water-soluble polymer of the bottom adhesive composition, so as to ensure that the bottom adhesive film layer and the top photoresist layer are separated.

[0043] If a water-soluble polymer is not introduced into the bottom resist layer, even if the alkali-soluble resin and the crosslinking agent undergo a crosslinking reaction at high temperature to form a high-molecular polymer, it cannot resist the solvent of the photoresist composition. During the coating process of the upper photoresist, it will mix with the bottom resist layer, thus failing to form a pattern with undercut. This application utilizes commonly used raw materials to achieve the design of the bottom sacrificial layer. The purpose of adding the water-soluble polymer is twofold: first, to reduce the solubility of the alkali-soluble resin of the bottom sacrificial layer in the organic solvent of the top photoresist layer, resisting the organic solvent and preventing the two layers from dissolving together; second, to enable the bottom sacrificial layer to dissolve in the developer, and the dissolution rate is greater than that of the top photoresist layer, thus forming an undercut.

[0044] See Figure 4 As shown, the target pattern formed by the method for forming photoresist patterns in this application has an undercut, as referenced. Figure 5 As shown, although the metal 20 deposited on the photoresist is still attached to the sidewalls of the photoresist, due to the undercut, the target metal pattern deposited at the non-photoresist location is disconnected from the metal on the sidewalls. The metal deposited on the photoresist is detached along with the photoresist during the stripping process, thus forming... Figure 6The desired graphic 22 is shown.

[0045] Figure 7 A scanning electron microscope (SEM) image of the morphology of a photoresist pattern after its formation according to an embodiment of this application is shown, with reference to... Figure 7 As shown, the recessed depth of the bottom sacrificial layer compared to the top photoresist layer is D.

[0046] It should be noted that the various characteristics and parameters described in the base adhesive composition also apply to the two-layer system and its application in semiconductor manufacturing processes.

[0047] The present application is further illustrated by the following embodiments, but the present application is not limited thereto.

[0048] Example 1: The mass ratio of alkali-soluble resin to water-soluble polymer was 3:1. The alkali-soluble resin was a phenolic resin with a weight average molecular weight of 30,000; the water-soluble polymer was polyvinylpyrrolidone with a weight average molecular weight of 3,000. The crosslinking agent was compound 1. The organic solvent was ethyl lactate:benzyl alcohol = 95:5.

[0049] Example 2: The mass ratio of alkali-soluble resin to water-soluble polymer was 20:1. The alkali-soluble resin was a phenolic resin with a weight average molecular weight of 30,000; the water-soluble polymer was polyvinylpyrrolidone with a weight average molecular weight of 3,000. The crosslinking agent was compound 1. The organic solvent was ethyl lactate:benzyl alcohol = 95:5.

[0050] Comparative Example 1: The mass ratio of alkali-soluble resin to water-soluble polymer was 2:1. The alkali-soluble resin was a phenolic resin with a weight average molecular weight of 30,000; the water-soluble polymer was polyvinylpyrrolidone with a weight average molecular weight of 3,000. The crosslinking agent was compound 1. The organic solvent was ethyl lactate:benzyl alcohol = 95:5.

[0051] Comparative Example 2: The mass ratio of alkali-soluble resin to water-soluble polymer was 25:1. The alkali-soluble resin was a phenolic resin with a weight average molecular weight of 30,000; the water-soluble polymer was polyvinylpyrrolidone with a weight average molecular weight of 3,000. The crosslinking agent was compound 1. The organic solvent was ethyl lactate:benzyl alcohol = 95:5.

[0052] Example 3: The mass ratio of alkali-soluble resin to water-soluble polymer was 5:1. The alkali-soluble resin was an acrylic resin (Sartoma CN115 NS) with a weight average molecular weight of 1000; the water-soluble polymer was polyvinyl alcohol with a weight average molecular weight of 1000. The crosslinking agent was compound 18. The organic solvent was ethyl lactate:benzyl alcohol = 95:5.

[0053] Example 4: The mass ratio of alkali-soluble resin to water-soluble polymer was 5:1. The alkali-soluble resin was an acrylic resin (Mitsubishi BR-115) with a weight average molecular weight of 50,000; the water-soluble polymer was polyvinyl alcohol with a weight average molecular weight of 1,000. The crosslinking agent was compound 18. The organic solvent was ethyl lactate:benzyl alcohol = 95:5.

[0054] Example 5: The mass ratio of alkali-soluble resin to water-soluble polymer was 5:1. The alkali-soluble resin was an acrylic resin (Sartoma CN115 NS) with a weight average molecular weight of 1000; the water-soluble polymer was polyvinyl alcohol with a weight average molecular weight of 100,000. The crosslinking agent was compound 18. The organic solvent was ethyl lactate:benzyl alcohol = 95:5.

[0055] Example 6: The mass ratio of alkali-soluble resin to water-soluble polymer was 5:1. The alkali-soluble resin was an acrylic resin (Mitsubishi BR-115, Japan) with a weight average molecular weight of 50,000; the water-soluble polymer was polyvinyl alcohol with a weight average molecular weight of 100,000. The crosslinking agent was compound 18. The organic solvent was ethyl lactate:benzyl alcohol = 95:5.

[0056] Example 7: The mass ratio of alkali-soluble resin to water-soluble polymer was 15:1. The alkali-soluble resin was a hydroxystyrene-based resin (Shanghai Bayi Space-Time Advanced Materials Co., Ltd. BPN-10000 / 03 / 1-35) with a dissolution rate of 50 Å / s in the developer; the water-soluble polymer was polyethyleneimine with a dissolution rate of 1100 Å / s in the developer. The crosslinking agent was compound 31, with an epoxy equivalent of 200 and a molecular weight of 1000. The organic solvent was ethyl lactate.

[0057] Example 8: The mass ratio of alkali-soluble resin to water-soluble polymer was 15:1. The alkali-soluble resin was a hydroxystyrene-based resin (Shanghai Bayi Space-Time Advanced Materials Co., Ltd. BPN-9000 / 03 / 1-35) with a dissolution rate of 150 Å / s in the developer; the water-soluble polymer was polyethyleneimine with a dissolution rate of 1100 Å / s in the developer. The crosslinking agent was compound 31 with an epoxy equivalent of 200 and a molecular weight of 1000. The organic solvent was ethyl lactate.

[0058] Example 9: The mass ratio of alkali-soluble resin to water-soluble polymer was 15:1. The alkali-soluble resin was a hydroxystyrene-based resin (Shanghai Bayi Space-Time Advanced Materials Co., Ltd. BPN-8000 / 03 / 1-35) with a dissolution rate of 200 Å / s in the developer; the water-soluble polymer was polyethyleneimine with a dissolution rate of 1100 Å / s in the developer. The crosslinking agent was compound 31 with an epoxy equivalent of 200 and a molecular weight of 1000. The organic solvent was ethyl lactate.

[0059] Example 10: The mass ratio of alkali-soluble resin to water-soluble polymer was 15:1. The alkali-soluble resin was a hydroxystyrene-based resin (Shanghai Bayi Space-Time Advanced Materials Co., Ltd. BPN-10000 / 03 / 1-35) with a dissolution rate of 50 Å / s in the developer; the water-soluble polymer was polyethyleneimine with a dissolution rate of 2000 Å / s in the developer. The crosslinking agent was compound 31 with an epoxy equivalent of 200 and a molecular weight of 1000. The organic solvent was ethyl lactate.

[0060] Comparative Example 3: The mass ratio of alkali-soluble resin to water-soluble polymer was 15:1. The alkali-soluble resin was a hydroxystyrene-based resin (Shanghai Bayi Space-Time Advanced Materials Co., Ltd. BPN-6000 / 03 / 1-35) with a dissolution rate of 400 Å / s in the developer; the water-soluble polymer was polyethyleneimine with a dissolution rate of 800 Å / s in the developer. The crosslinking agent was compound 31, with an epoxy equivalent of 200 and a molecular weight of 1000. The organic solvent was ethyl lactate.

[0061] Comparative Example 4: Only alkali-soluble resin and crosslinking agent were added, without water-soluble polymer.

[0062] Comparative Example 5: Only alkali-soluble resin was used, without the addition of water-soluble polymers and crosslinking agents.

[0063] The formulations for each embodiment and comparative example are shown in Table 1 below:

[0064] Alkali-soluble resin / wt% Water-soluble polymers / wt% Crosslinking agent / wt% Organic solvents / wt% Additives / wt% Example 1 14 4.7 1 80 0.3 Example 2 17.8 0.9 1 80 0.3 Example 3 15.6 3.1 1 80 0.3 Example 4 15.6 3.1 1 80 0.3 Example 5 15.6 3.1 1 80 0.3 Example 6 15.6 3.1 1 80 0.3 Example 7 17.5 1.2 1 80 0.3 Example 8 17.5 1.2 1 80 0.3 Example 9 17.5 1.2 1 80 0.3 Example 10 17.5 1.2 1 80 0.3 Comparative Example 1 12.5 6.2 1 80 0.3 Comparative Example 2 18 0.7 1 80 0.3 Comparative Example 3 17.5 1.2 1 80 0.3 Comparative Example 4 18.7 none 1 80 0.3 Comparative Example 5 19.7 none none 80 0.3

[0065] Top-layer photoresist composition: 20 wt% of cresol phenolic resin with a molecular weight of 10,000, 5 wt% of photosensitizer, 74.95 wt% of propylene glycol methyl ether acetate solvent, and 0.05 wt% of additives.

[0066] Method for forming photoresist patterns: The underlying photoresist composition of the above-described embodiments or comparative examples is coated onto a substrate using spin coating. The coated underlying photoresist composition is baked at 170°C for 120 seconds to form an underlying photoresist film layer. A positive photoresist composition is coated on top of the underlying photoresist film layer using spin coating. The coated positive photoresist composition is baked at 100°C for 60 seconds. Using a photomask, the obtained photoresist layer is exposed on a photolithography machine. The exposed underlying photoresist film layer and photoresist layer are then placed in a developing solution for development. The developing solution is a tetramethylammonium hydroxide aqueous solution with a concentration range of 0.4~3.5%, and the development time is 120 seconds.

[0067] Table 2 below summarizes the recess depth D of the bottom sacrificial layer relative to the top photoresist layer in various embodiments and comparative examples.

[0068] Depth D, um Example 1 6.3 Example 2 0.25 Example 3 4.7 Example 4 0.8 Example 5 3.6 Example 6 0.43 Example 7 1.8 Example 8 2.1 Example 9 2.3 Example 10 4.1 Comparative Example 1 The undercut pattern was not formed due to excessively fast development speed. Comparative Example 2 Because the mixed adhesives did not form an undercut pattern Comparative Example 3 Because the mixed adhesives did not form an undercut pattern Comparative Example 4 Because the mixed adhesives did not form an undercut pattern Comparative Example 5 Because the mixed adhesives did not form an undercut pattern

[0069] Table 2

[0070] The above description is merely a preferred embodiment of this application and is not intended to limit this application. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A base adhesive composition, characterized in that, The undercoat composition comprises: Alkali-soluble resins; A water-soluble polymer, wherein the dissolution rate of the water-soluble polymer in the developer is greater than the dissolution rate of the alkali-soluble resin in the developer; A crosslinking agent is used to crosslink the alkali-soluble resin with the water-soluble polymer; An organic solvent capable of simultaneously dissolving the alkali-soluble resin and the water-soluble polymer; additive; The underlying adhesive composition does not contain photosensitizers.

2. The undercoat composition according to claim 1, characterized in that, The mass ratio of the alkali-soluble resin to the water-soluble polymer is 3-20:1, preferably 5-15:

1.

3. The undercoat composition according to claim 1, characterized in that, The alkali-soluble resin has a dissolution rate of less than 300 Å / s in the developer, and the water-soluble polymer has a dissolution rate of greater than 1000 Å / s in the developer. Preferably, the alkali-soluble resin has a dissolution rate in the developer between 50 and 150 Å / s, and the water-soluble polymer has a dissolution rate in the developer greater than 2000 Å / s.

4. The undercoat composition according to claim 1, characterized in that, The weight-average molecular weight of the alkali-soluble resin is between 1,000 and 50,000, and the weight-average molecular weight of the water-soluble polymer is between 1,000 and 100,000. Preferably, the weight-average molecular weight of the alkali-soluble resin is between 10,000 and 50,000, and the weight-average molecular weight of the water-soluble polymer is between 5,000 and 50,000.

5. The undercoat composition according to claim 1, characterized in that, The alkali-soluble resin is one or more of the following: phenolic resin, acrylic resin, methacrylic resin, hydroxystyrene resin, polyimide resin, and silicone resin.

6. The undercoat composition according to claim 1, characterized in that, The water-soluble polymer is one or more of the following: polyvinylpyrrolidone, polyvinyl alcohol, polyethylene glycol, polyether polyol, polyacrylic acid, polyethyleneimine, polyethyleneamine, polyallylamine, alkyd resin, and sulfonamide resin.

7. The undercoat composition according to claim 1, characterized in that, The crosslinking agent is one or more of melamine resin, epoxy monomer having at least two epoxy groups, and epoxy phenolic resin.

8. The undercoat composition according to claim 1, characterized in that, The organic solvent is one or more of benzyl alcohol, benzyl alcohol, γ-butyrolactone, ethyl lactate, propylene glycol monomethyl ether, ethylene glycol methyl ether, ethylene glycol ethyl ether, ethylene glycol butyl ether, diethylene glycol dimethyl ether, and N-methylpyrrolidone.

9. The undercoat composition according to claim 2, characterized in that, Based on the mass of the underlying adhesive composition as 100%, the mass fraction of the alkali-soluble resin is 5%-40%, the mass fraction of the water-soluble polymer is 0.01%-10%, the mass fraction of the crosslinking agent is 0.01%-10%, the mass fraction of the additive is 0.01%-5%, and the mass fraction of the organic solvent is 40%-90%.

10. A two-layer system, characterized in that, It includes a top photoresist layer formed from a photoresist composition and a bottom resist film layer formed from a bottom resist composition according to any one of claims 1-9, wherein the top photoresist layer is located on the bottom resist film layer, and wherein the water-soluble polymer is not soluble in the organic solvent in the photoresist composition.

11. An application of the bilayer system of claim 10 in a semiconductor manufacturing process, characterized in that: The two-layer system is exposed and developed.

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