A photoresist composed of a leptin compound, its preparation method and application

Abstract

This invention discloses a photoresist composed of pterene compounds, its preparation method, and its applications. The photoresist composition provided by this invention comprises the following components: pterene A as shown in the following formula, pterene B as shown in the following formula, a photoacid generator, an organic solvent, and an organic base. The photoresist can be used in EUV lithography technology, possessing the characteristics of high resolution, high sensitivity, and high photosensitivity, and has broad application prospects.

Description

Technical Field

[0001] This invention belongs to the field of photoresist technology, specifically relating to a photoresist composed of a leptin compound, its preparation method, and its application. Background Technology

[0002] With the continuous development of modern semiconductor technology and its widespread application in electronic devices, communication equipment, information security, and entertainment devices, it has become one of the most dynamic technological fields in the world today, permeating all aspects of our work and life. Integrated circuit manufacturing is the core area of ​​the semiconductor industry. Every upgrade of integrated circuits is inseparable from the evolution of photolithography technology; the history of photolithography technology is the history of integrated circuit development, and the level of photolithography technology determines the manufacturing level of integrated circuits.

[0003] The principle of photolithography is to coat the surface of a silicon wafer with a layer of highly photosensitive photoresist, and then shine light (usually ultraviolet, deep ultraviolet, or extreme ultraviolet light) through a mask onto the silicon wafer surface. The photoresist exposed to the light reacts. Afterwards, the exposed / unexposed photoresist is washed away with a specific solvent, thus transferring the circuit pattern from the mask to the silicon wafer. Photolithography technology has undergone transformations in exposure methods, from contact / proximity, equal-magnification projection, shrinkage step projection, and scanning step projection. Exposure wavelengths have evolved from full-spectrum exposure (300-450nm), to 436nm G-lines, 365nm I-lines, 248nm KrF lasers, to the most widely used 193nm ArF lasers, and now to the widely researched 13.5nm extreme ultraviolet light, electron beams, and X-rays. Manufacturing nodes have progressed from 0.5mm, 0.1mm, 90nm to 30nm, and even lower. Extreme ultraviolet lithography differs from traditional optical lithography in that it has an extremely short wavelength. However, most elements have strong absorption of extreme ultraviolet (EUV) light, making traditional long-wavelength photoresists unsuitable for EUV lithography. Therefore, new EUV photoresist systems need to be developed. Photolithography is one of the most critical technologies in integrated circuit manufacturing. The successful application of each generation of photolithography technology has greatly promoted the development of integrated circuits, leading to higher integration density and lower costs. Photolithography is the process of exposing photoresist material coated on the surface of a semiconductor substrate to transfer the intricate geometric patterns on the mask onto the semiconductor substrate. The increasing resolution of photolithographic patterns means higher integration density and smaller critical dimensions in integrated circuits.

[0004] The semiconductor industry currently agrees that extreme ultraviolet (EUV) lithography (13.5nm) is a promising next-generation lithography technology. Due to its extremely short wavelength, the final resolution will be limited only by the material properties of the photoresist. EUV lithography can produce higher-resolution circuit patterns, significantly improving the integration density of integrated circuits and the performance of electronic devices. Researching photoresists and lithography processes suitable for EUV lithography has become both a hot topic and a challenge in lithography research.

[0005] EUV photoresists must possess characteristics such as low absorbance, high transparency, high etch resistance, high resolution, high sensitivity, low exposure dose, high environmental stability, low gas generation, and low line edge roughness. The development of EUV photoresists has been limited by three factors: resolution, line edge roughness, and photosensitivity, which generally exhibit an interdependent relationship. In early photolithography technologies, polymer photoresists were the most widely used; therefore, polymer photoresist systems were initially applied to EUV lithography. The industry urgently needs to develop EUV photoresists that improve resolution. Summary of the Invention

[0006] The technical problem this invention aims to solve is the limited variety and poor selectivity of existing EUV photoresists. Therefore, it provides a photoresist composition composed of pterene compounds, its preparation method, and its applications. The photoresist provided by this invention features high resolution, high sensitivity, and high photosensitivity, and has a wide range of applications.

[0007] This invention provides a photoresist composition comprising the following components: pterene A as shown in the following formula, pterene B as shown in the following formula, a photoacid generator, an organic solvent, and an organic base;

[0008]

[0009] The pterene A is present in 50-70 parts by weight, and the pterene B is present in 30-50 parts by weight.

[0010] In the photoresist composition, the photoacid generator can be a conventional photoacid generator in the photoresist field, such as...

[0011] In the photoresist composition, the organic solvent can be a conventional organic solvent in the photoresist field, such as an ester solvent; preferably ethyl lactate.

[0012] In the photoresist composition, the organic base can be a conventional organic base in the field of photoresist, preferably a weak organic base, such as trioctylamine.

[0013] In the photoresist composition, the pterene A is preferably present in 60 parts by weight.

[0014] In the photoresist composition, the pterene B is preferably present in 40 parts by weight.

[0015] In the photoresist composition, the number of parts by weight of the photoacid generator can be a conventional number in the art, such as 1-10 parts, preferably 7 parts.

[0016] In the photoresist composition, the organic solvent can be in parts by weight in a number that is conventional in the art, such as 1,000-2,000 parts, preferably 1,500 parts.

[0017] In the photoresist composition, the organic base can be in the conventional amount by weight, preferably 0.2-1 parts, more preferably 0.5 parts.

[0018] In one specific embodiment, the photoacid-generating agent is 1-10 parts by weight.

[0019] The organic solvent is ethyl lactate in 1000-2000 parts by weight;

[0020] The organic base is 0.2-1 parts by weight of trioctylamine.

[0021] In one specific embodiment, the photoresist composition comprises the following components: the above-mentioned pterene A, the above-mentioned pterene B, the above-mentioned photoacid generator, the above-mentioned organic solvent, and the above-mentioned organic base;

[0022] Wherein, compound A refers to the type and content of compound A; pterene B refers to the type and content of pterene B; photoacid generator refers to the type and content of photoacid generator; and organic base refers to the type and content of organic base.

[0023] The photoresist composition is preferably composed of any one of the following components in parts by weight: pterene A, pterene B, photoacid generator, organic solvent, and organic base.

[0024] Photoresist composition 1: 60 parts of the pterene A, 40 parts of the pterene B, 7 parts of the photoacid generator, 1500 parts of the organic solvent and 0.5 parts of the organic base;

[0025] Photoresist composition 2: 50 parts of the pterene A, 30 parts of the pterene B, 1 part of the photoacid generator, 1000 parts of the organic solvent and 0.5 parts of the organic base;

[0026] Photoresist composition 3: 55 parts of the pterene A, 35 parts of the pterene B, 3 parts of the photoacid generator, 1200 parts of the organic solvent and 0.5 parts of the organic base;

[0027] Photoresist composition 4: 65 parts of the pterene A, 45 parts of the pterene B, 5 parts of the photoacid generator, 1600 parts of the organic solvent, and 0.5 parts of the organic base;

[0028] Photoresist composition 5: 70 parts of the pterene A, 50 parts of the pterene B, 10 parts of the photoacid generator, 2000 parts of the organic solvent, and 0.5 parts of the organic base;

[0029] Photoresist composition 6: 66 parts of the pterene A, 38 parts of the pterene B, 7 parts of the photoacid generator, 1500 parts of the organic solvent, and 0.5 parts of the organic base;

[0030] Photoresist composition 7: 62 parts of the pterene A, 46 parts of the pterene B, 7 parts of the photoacid generator, 1500 parts of the organic solvent, and 0.5 parts of the organic base;

[0031] Photoresist composition 8: 50 parts of the pterene A, 50 parts of the pterene B, 7 parts of the photoacid generator, 1500 parts of the organic solvent and 0.5 parts of the organic base;

[0032] In photoresist compositions 1-8, the photoacid generator is... The organic solvent is ethyl lactate, and the organic base is trioctylamine.

[0033] The present invention also provides a method for preparing a photoresist composition, which includes the following steps: mixing the components of the photoresist composition evenly.

[0034] The mixture may further include a filtration step. The filtration can be a conventional method, preferably using an ultra-high molecular weight polyethylene (UHMWPE) membrane. The UHMWPE membrane preferably has a pore size of 0.1 μm.

[0035] The present invention also provides a method for forming patterns using photolithography, the method comprising the following steps:

[0036] Step 1: Coat the above photoresist composition onto the substrate surface and bake to obtain a photoresist layer;

[0037] Step 2: Expose, bake, and develop the photoresist layer obtained in Step 1 to obtain the photoresist pattern.

[0038] In step 1, the substrate can be a conventional substrate in the art, preferably a wafer, such as an 8-inch wafer.

[0039] In step 1, the coating method can be a conventional method in the art, preferably spin coating with a rotary coater.

[0040] In step 1, when using a rotary coater for spin coating, the preferred rotation speed of the coater is 2000-3000 rpm, for example, 2500 rpm.

[0041] In step 1, the thickness of the photoresist layer can be a conventional thickness in the art, preferably 40-60nm, for example 50nm.

[0042] In step 1, the baking temperature can be a conventional baking temperature in the art, preferably 70-90°C, for example 80°C.

[0043] In step 1, the baking time can be a conventional baking time in the art, preferably 50-70 seconds, for example 60 seconds.

[0044] In step 2, the baking temperature can be a conventional baking temperature in the art, preferably 120-140℃, for example 130℃.

[0045] In step 2, the baking time can be a conventional baking time in the art, preferably 50-70 seconds, for example 60 seconds.

[0046] In step 2, the developing process can be a conventional operation in the art. The developing agent generally used is an aqueous solution of tetramethylammonium hydroxide, such as an aqueous solution of tetramethylammonium hydroxide with a mass fraction of 2.38%.

[0047] Without violating common sense in the field, the above-mentioned preferred conditions can be combined arbitrarily to obtain various preferred embodiments of the present invention.

[0048] The resin used in this invention is self-made, while all other reagents and raw materials used are commercially available.

[0049] The positive and progressive effects of this invention are that the photoresist provided by this invention has better resolution, photosensitivity, and lower line edge roughness. Therefore, the EUV photoresist composition of this invention has good application prospects. Detailed Implementation

[0050] The present invention is further illustrated below by way of embodiments, but the invention is not limited to the scope of the embodiments described herein. Experimental methods in the following embodiments that do not specify specific conditions were performed according to conventional methods and conditions, or as selected according to the product instructions.

[0051] Examples 1-8 and Comparative Examples 1-8 for the preparation of photoresist compositions

[0052] According to the combination and content shown in Table 1, the components were mixed evenly and filtered through a 0.1 μm ultra-high molecular weight polyethylene membrane to obtain a photoresist composed of phenene compounds.

[0053] Where pterene A is

[0054] Where pterene B is

[0055] Among them, the photoacid generator is... The organic solvent is ethyl lactate; the organic base is trioctylamine.

[0056] Table 1

[0057]

[0058] Effect Example

[0059] 1. EUV exposure and testing

[0060] Photoresist film preparation and exposure: The prepared photoresist was applied to an 8-inch wafer using a spin coater at 2500 RPM, and then heated at 80°C for 60 seconds on a hot plate to obtain the photoresist film. The average film thickness of 50 nm was measured at 25 points using an F50 (Filmetrics) optical film thickness measurement system. Extreme ultraviolet exposure was performed on the Shanghai Synchrotron Radiation Facility interferometric lithography line station (BL08U1B), followed by baking at 130°C for 60 seconds. Finally, development was performed in a 2.38 wt% tetramethylammonium hydroxide (TMAH) aqueous solution to obtain the pattern.

[0061] LER determination: LER of 50-nm LS pattern was measured under FE-SEM (Hitachi SU9000).

[0062] LWR determination: The LWR of the 50-nm LS pattern was measured under CD-SEM (HITACHI, CD-SEM, CG5000).

[0063] Sensitivity testing: An Ethmeter was used as the sensitivity indicator. A stepped 25-point exposure at different energies (e.g., 0.5 mJ / cm²) was performed on an 8-inch wafer. 2 1mJ / cm 2 1.5 mJ / cm 2 ...), after post-baking (PEB), development is performed, and the film thickness is measured. The film thickness that just reaches 0 nm is recorded as Eth.

[0064] Resolution detection: Under the above sensitivity conditions, the limiting resolution (the minimum width limit when separating and resolving lines and spacing) under the exposure dose (the dose of electron beam irradiation) is taken as the LS resolution.

[0065] Table 2

[0066]

[0067]

[0068] 2. EB Exposure and Detection

[0069] Photoresist film preparation and exposure: Photoresist was applied to an 8-inch wafer using a spin coater at 2500 RPM, and then heated at 80°C for 60 seconds on a hot plate to obtain the photoresist film. The average film thickness of 50 nm was measured at 25 points using an F50 (Filmetrics) optical film thickness measurement system. The photoresist was exposed to an electron beam using an Elionix ELS-G100 EB writing system (elionix, accelerating voltage 100 keV) and then baked at 130°C for 60 seconds. Finally, it was developed in a 2.38 wt% tetramethylammonium hydroxide (TMAH) aqueous solution to obtain the pattern.

[0070] Eop: Optimal exposure (Eop) is defined as providing an exposure dose with 1:1 resolution at the top and bottom of a 50-nm 1:1 line-and-space (LS) pattern.

[0071] LER determination: LER of 50-nm LS pattern was measured under FE-SEM (Hitachi SU9000).

[0072] LWR determination: The LWR of the 50-nm LS pattern was measured under CD-SEM (HITACHI, CD-SEM, CG5000).

[0073] Resolution detection: Under the above Eop conditions, the limiting resolution (the minimum width limit when separating and resolving lines and spacing) under the exposure dose (the dose of electron beam irradiation) is taken as the LS resolution.

[0074] Table 3

[0075]

[0076]

Claims

1. A photoresist composition, characterized in that, It contains the following components: pterene A as shown in the following formula, pterene B as shown in the following formula, photoacid generator, organic solvent and organic base; The pterene A is present in 50-70 parts by weight, and the pterene B is present in 30-50 parts by weight.

2. The photoresist composition according to claim 1, characterized in that, The photoresist composition satisfies one or more of the following conditions; (1) The photoacid generator is (2) The organic solvent is an ester solvent; (3) The organic base is a weak organic base.

3. The photoresist composition according to claim 1, characterized in that, The organic solvent is ethyl lactate; And / or, the organic base is trioctylamine.

4. The photoresist composition according to claim 1, characterized in that, The photoresist composition satisfies one or more of the following conditions; (1) The pterene A is 60 parts by weight; (2) The number of parts of the pterene B by weight is 40; (3) The amount of the photo-acid-generating agent is 1-10 parts by weight; (4) The organic solvent is in parts by weight of 1000-2000 parts; (5) The organic base is 0.2-1 parts by weight.

5. The photoresist composition according to claim 4, characterized in that, The photoresist composition satisfies one or more of the following conditions; (1) The photo-acid-generating agent is 7 parts by weight; (2) The organic solvent is 1500 parts by weight; (3) The organic base is 0.5 parts by weight.

6. The photoresist composition according to claim 1, characterized in that, The photoacid-generating agent is 1-10 parts by weight. The organic solvent is ethyl lactate in 1000-2000 parts by weight; The organic base is 0.2-1 parts by weight of trioctylamine.

7. The photoresist composition according to any one of claims 1-6, characterized in that, It is composed of the following components: pterene A, pterene B, photoacid generator, organic solvent, and organic base.

8. The photoresist composition according to claim 1, characterized in that, It is composed of any one of the following components by weight: pterene A, pterene B, photoacid generator, organic solvent, and organic base. Photoresist composition 1: 60 parts of the pterene A, 40 parts of the pterene B, 7 parts of the photoacid generator, 1500 parts of the organic solvent and 0.5 parts of the organic base; Photoresist composition 2: 50 parts of the pterene A, 30 parts of the pterene B, 1 part of the photoacid generator, 1000 parts of the organic solvent and 0.5 parts of the organic base; Photoresist composition 3: 55 parts of the pterene A, 35 parts of the pterene B, 3 parts of the photoacid generator, 1200 parts of the organic solvent and 0.5 parts of the organic base; Photoresist composition 4: 65 parts of the pterene A, 45 parts of the pterene B, 5 parts of the photoacid generator, 1600 parts of the organic solvent, and 0.5 parts of the organic base; Photoresist composition 5: 70 parts of the pterene A, 50 parts of the pterene B, 10 parts of the photoacid generator, 2000 parts of the organic solvent, and 0.5 parts of the organic base; Photoresist composition 6: 66 parts of the pterene A, 38 parts of the pterene B, 7 parts of the photoacid generator, 1500 parts of the organic solvent, and 0.5 parts of the organic base; Photoresist composition 7: 62 parts of the pterene A, 46 parts of the pterene B, 7 parts of the photoacid generator, 1500 parts of the organic solvent, and 0.5 parts of the organic base; Photoresist composition 8: 50 parts of the pterene A, 50 parts of the pterene B, 7 parts of the photoacid generator, 1500 parts of the organic solvent and 0.5 parts of the organic base; In photoresist compositions 1-8, the photoacid generator is... The organic solvent is ethyl lactate, and the organic base is trioctylamine.

9. A method for preparing the photoresist composition according to any one of claims 1-8, characterized in that, Simply mix all components of the photoresist composition evenly.

10. A method for forming a pattern using photolithography, characterized in that, The method includes the following steps: Step 1: Coat the substrate surface with the photoresist composition as described in any one of claims 1-8, and bake to obtain a photoresist layer; Step 2: Expose, bake, and develop the photoresist layer obtained in Step 1 to obtain the photoresist pattern.

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