Titanium-based-dienediol dry photoresist and preparation method thereof

Abstract

The invention discloses a titanium-based-dienediol dry photoresist and a preparation method thereof, and the preparation method of the titanium-based-dienediol dry photoresist comprises the following steps: taking a titanium source and dienediol as precursors, carrying out molecular layer deposition, and obtaining the titanium-based-dienediol dry photoresist after deposition. According to the invention, the chemical synthesis step and the coating step are combined, so that the photoresist does not need to be synthesized in advance, and then the photoresist is covered on the surface of the silicon wafer by using a spin coating method. Compared with the characteristic of non-uniform thickness at positions with different linear speeds in a spin-coating process, the dry process has good uniformity, does not need to use a chemical solvent, and has great advantages in the aspects of use cost, environmental friendliness and post-treatment compared with a wet process using spin-coating. The line resolution ratio of the titanium-based-dienediol dry type photoresist can reach 7.9 nm, and meanwhile, the sensitivity of the titanium-based-dienediol dry type photoresist in 30 kV electron beam exposure reaches 0.54 mC / cm < 2 >.

Description

Technical Field

[0001] This invention belongs to the field of photoresist technology, specifically relating to a titanium-based diene glycol dry photoresist and its preparation method. Background Technology

[0002] Photolithography is a key technology for the further development of large-scale integrated circuits. The minimum size of the photolithography process is directly related to the upper limit of development in the microelectronics field. Over the past few decades, photolithography process nodes have evolved from 248nm to 193nm, then to immersion 193nm, and currently to the 13.5nm EUV extreme ultraviolet lithography technology. For the world today, the light source is no longer the most critical issue hindering the development of photolithography technology. Photoresist is the object processed in the photolithography process; it plays a role in pattern transfer during micro- and nano-manufacturing and is the most critical consumable in this process.

[0003] Currently, most organic photoresists are composed of light elements such as C, H, and O. These elements have weak absorption of EUV light, making them difficult to utilize effectively and resulting in significant losses. Traditional polymer photoresists, to achieve patterning effects, typically use anti-reflective layers of varying thicknesses (200nm-300μm) and anti-etching layers to enhance etching resistance. The introduction of these underlayers increases the vertical unevenness of the photoresist, resulting in high line edge roughness (LER) and line width roughness (LWR) during high-resolution exposure in the EUV band. Dry photoresists possess excellent photon trapping capabilities; however, existing dry photoresists have low line resolution and sensitivity. Low sensitivity significantly increases exposure time, leading to pattern distortion and increased exposure costs. Low resolution prevents the transfer of smaller patterns onto the photoresist, while also resulting in relatively high LER and LWR. Therefore, developing a dry photoresist with high line resolution and sensitivity is of paramount importance now and in the future for the further development of photolithography processes. Summary of the Invention

[0004] In order to solve the problems mentioned in the background art, the purpose of this invention is to provide a titanium-based diene glycol dry photoresist and its preparation method.

[0005] To achieve the above objectives, the technical solution adopted by the present invention is as follows: On the one hand, the present invention provides a method for preparing titanium-based diene glycol dry photoresist, using titanium source and diene glycol as precursors, performing molecular layer deposition, and obtaining titanium-based diene glycol dry photoresist after deposition.

[0006] Furthermore, the titanium source is at least one of tetra(dimethylamino)titanium, tetra(diethylamino)titanium, tetra(ethylmethylamino)titanium, trimethoxy(pentamethylcyclopentadienyl)titanium, tetra(ethoxy)titanium, titanium tetrachloride, trichloromonocenetitanium, isopropyl titanate, dichloromonocenetitanium, and tris(dimethylamino)cyclopentadienyltitanium (CpTi).

[0007] Further, the dienediol is at least one of 1,5-hexadien-3,4-diol and its isomers, 1,5-heptadien-3,4-diol and its isomers, and 2,6-dimethyl-3,7-octadien-2,6-diol and its isomers.

[0008] Further, the specific steps of the molecular layer deposition are as follows: heating the titanium source to 328-483K, heating the diene glycol to 353-433K, maintaining the reactor temperature at 353-433K, and purging the reaction with 20-40 sccm of dry nitrogen gas. Each complete cycle of the molecular layer deposition process consists of two reactions: (1) blowing in the titanium source for reaction, followed by blowing in nitrogen gas to purge all reaction gases; (2) blowing in the diene glycol for reaction, followed by blowing in nitrogen gas to purge all reaction gases. The thickness of the titanium-based diene glycol dry photoresist is controlled according to the number of deposition cycles.

[0009] Furthermore, the molecular layer deposition reaction is carried out on a silicon or silicon dioxide substrate.

[0010] Furthermore, the deposition thickness is 0.1 nanometers per cycle.

[0011] Furthermore, the titanium source combines with the hydroxyl bonds on the diene glycol to form a titanium-diene-titanium structure.

[0012] On the other hand, the present invention provides a titanium-based diene glycol dry photoresist, which is prepared by any of the preparation methods described above.

[0013] Compared with the prior art, the present invention has the following beneficial effects:

[0014] (1) The line resolution of the titanium-based diene glycol dry photoresist of this invention can reach 7.9 nm, which is much higher than 25 nm. Simultaneously, the sensitivity of the titanium-based diene glycol dry photoresist reaches 0.54 mC / cm under 30 kV electron beam exposure. 2 It is already close to traditional organic photoresists in dry photoresist.

[0015] (2) In the extreme ultraviolet (EUV) band, the titanium element in the titanium-based diene glycol dry photoresist of this invention has a much higher light absorption area compared to traditional C, H, and O photoresists, enabling it to efficiently absorb EUV light and emit photogenerated electrons. Simultaneously, titanium exhibits good etching resistance. The entire exposure system can be compressed to a thickness of 20 nm, meeting the requirements of next-generation photolithography processes for photoresist thickness. Furthermore, the lower thickness reduces the vertical unevenness of the entire exposure system. The introduction of dienes into the titanium-based diene glycol dry photoresist of this invention, along with the increased content of unsaturated hydrocarbons, significantly enhances the EUV light reaction.

[0016] (3) The preparation method of this invention grows directly on silicon or silicon dioxide through a chemical reaction. This invention combines the chemical synthesis step with the coating step, eliminating the need for pre-synthesizing the photoresist before spin coating to cover the silicon wafer surface. Compared to the uneven thickness at different linear velocities in spin coating, the dry process has good uniformity and does not require the use of chemical solvents, offering significant advantages in terms of cost, environmental friendliness, and post-processing compared to the wet process using spin coating. Furthermore, the molecular layer deposition method can precisely control the growth of a single atom or molecular cluster per cycle, resulting in more precise control over the film thickness, which can be accurately controlled at the 0.1 nm level. The photoresist of this invention exhibits better performance in thickness control and uniformity control of the photoresist film thickness compared to the spin coating method. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the preparation process of the titanium-based diene glycol dry photoresist prepared in Example 1 of the present invention;

[0018] Figure 2 The images show the effects of electron beam exposure and development of the titanium-diene glycol dry photoresist prepared in Example 3 of the present invention after different exposure doses.

[0019] Figure 3 This is a SEM image of the titanium-based diene glycol dry photoresist prepared in Example 4 of the present invention after exposure and development. Detailed Implementation

[0020] To better understand the content of this invention, the following detailed description is provided in conjunction with specific implementation methods. However, the scope of protection of this invention is not limited to the following embodiments.

[0021] Thin films are deposited in commercial ALD equipment.

[0022] Example 1

[0023] The preparation process of titanium-based diene glycol dry photoresist is shown in the schematic diagram below. Figure 1As shown: Tetra(dimethylamino)titanium was used as the titanium source and heated to 328K for vaporization. 1,5-hexadien-3,4-diol was used as the diene glycol source and the source flask containing 1,5-hexadien-3,4-diol was heated to 353K. The reactor temperature was maintained at 393K, and the reaction was purged with 20 sccm of dry nitrogen. Each complete cycle of the molecular layer deposition process consisted of two reactions: (1) 50 ms of gaseous tetra(dimethylamino)titanium was introduced at a partial pressure of 4.0 Pa, followed by 15 s of nitrogen purging; (2) 50 ms of gaseous 1,5-hexadien-3,4-diol was introduced at a partial pressure of 2.6 Pa, followed by 45 s of nitrogen purging. The deposition thickness was 30 nm after 300 cycles, i.e., 0.1 nm / cycle.

[0024] Example 2

[0025] The preparation of titanium-based diene glycol dry photoresist involved using tetra(dimethylamino)titanium as the titanium source, heated to 328K for vaporization, and 1,5-heptadien-3,4-diol as the diene glycol source, with the source flask containing 1,5-heptadien-3,4-diol heated to 393K. The reactor temperature was maintained at 393K, and the reaction was purged with 20 sccm of dry nitrogen. Each complete cycle of the molecular layer deposition process consisted of two reactions: (1) 50 ms of gaseous tetra(dimethylamino)titanium was introduced at a partial pressure of 4.0 Pa, followed by 15 s of nitrogen purging; and (2) 100 ms of gaseous 1,5-heptadien-3,4-diol was introduced at a partial pressure of 3.3 Pa, followed by 45 s of nitrogen purging. A thickness of 28 nm was achieved after 300 cycles, approximately 0.1 nm per cycle.

[0026] Example 3

[0027] Thin film sensitivity testing:

[0028] The preparation process of titanium-based diene glycol dry photoresist is shown in the schematic diagram below. Figure 1 As shown: Tetra(dimethylamino)titanium was used as the titanium source and heated to 328K for vaporization. 1,5-hexadien-3,4-diol was used as the diene glycol source and the source flask containing 1,5-hexadien-3,4-diol was heated to 353K. The reactor temperature was maintained at 393K, and the reaction was purged with 20 sccm of dry nitrogen. Each complete cycle of the molecular layer deposition process consisted of two reactions: (1) 50 ms of gaseous tetra(dimethylamino)titanium was introduced at a partial pressure of 4.0 Pa, followed by 15 s of nitrogen purging; (2) 50 ms of gaseous 1,5-hexadien-3,4-diol was introduced at a partial pressure of 2.6 Pa, followed by 45 s of nitrogen purging. After 200 cycles of deposition, the thickness was 21.6 nm.

[0029] The titanium-based diene glycol dry photoresist was exposed using electron beams with different exposure doses of 30 kV. The exposed titanium-based diene glycol dry photoresist was then post-baked at 373 K for 90 s, followed by development with N,N-dimethylformamide for 45 s. The effects of electron beam exposure and development with different exposure doses are shown below. Figure 2 As shown. From Figure 2 As can be seen from the exposure dose and step height, when the electron beam exposure dose reaches 540 μC / cm 2 At this point, the titanium-based diene glycol dry photoresist was almost completely exposed. Under 30kV electron beam exposure, the sensitivity of the titanium-based diene glycol dry photoresist reached 0.54 mC / cm. 2 It is already close to traditional organic photoresists in dry photoresist.

[0030] Example 4

[0031] Line resolution test of thin film:

[0032] The preparation process of titanium-based diene glycol dry photoresist is shown in the schematic diagram below. Figure 1 As shown: Tetra(dimethylamino)titanium was used as the titanium source and heated to 328 K for vaporization. 1,5-hexadien-3,4-diol was used as the diene glycol source and the source flask containing 1,5-hexadien-3,4-diol was heated to 353 K. The reactor temperature was maintained at 393 K, and the reaction was purged with 20 sccm of dry nitrogen. Each complete cycle of the molecular layer deposition process consisted of two reactions: (1) 50 ms of gaseous tetra(dimethylamino)titanium was introduced at a partial pressure of 4.0 Pa, followed by 15 s of nitrogen purging; (2) 50 ms of gaseous 1,5-hexadien-3,4-diol was introduced at a partial pressure of 2.6 Pa, followed by 45 s of nitrogen purging. After 180 cycles of deposition, the thickness was 19.2 nm.

[0033] A 50kV electron beam was used (exposure dose of 2.4mC / cm). 2 The titanium-based diene glycol dry photoresist was exposed, then post-baked at 373K for 90 seconds, followed by development with N,N-dimethylformamide for 45 seconds. SEM analysis was performed after exposure and development, and the results are shown below. Figure 3 As shown, from Figure 3 As can be seen, the electron beam is 50kV and the exposure dose is 2.4mC / cm. 2 The line width is 7.9nm. The line resolution of the titanium-based diene glycol dry photoresist can reach 7.9nm, which is basically the limit resolution of this electron beam lithography machine.

[0034] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several modifications and improvements can be made without departing from the inventive concept, and these all fall within the protection scope of the present invention.

Claims

1. A method for preparing a titanium-based diene glycol dry photoresist, characterized in that, Using titanium source and diene glycol as precursors, molecular layer deposition was performed to obtain titanium-based diene glycol dry photoresist.

2. The preparation method according to claim 1, characterized in that, The titanium source is at least one of tetra(dimethylamino)titanium, tetra(diethylamino)titanium, tetra(ethylmethylamino)titanium, trimethoxy(pentamethylcyclopentadiene)titanium, tetra(ethoxy)titanium, titanium tetrachloride, trichloromonocenetitanium, isopropyl titanate, dichloromonocenetitanium, and tri(dimethylamino)cyclopentadienetitanium.

3. The preparation method according to claim 1, characterized in that, The dienadiol is at least one of 1,5-hexadien-3,4-diol and its isomers, 1,5-heptadien-3,4-diol and its isomers, and 2,6-dimethyl-3,7-octadien-2,6-diol and its isomers.

4. The preparation method according to claim 1, characterized in that, The specific steps of the molecular layer deposition are as follows: the titanium source is heated to 328-483K, the diene glycol is heated to 353-433K, the temperature of the reactor is maintained at 353-433K, and the reaction is purged with 20-40 sccm of dry nitrogen. Each complete cycle of the molecular layer deposition process consists of two reactions: (1) the titanium source is blown in to react, and then nitrogen is introduced to purge all the reaction gases; (2) the diene glycol is blown in to react, and then nitrogen is introduced to purge all the reaction gases. The thickness of the titanium-based diene glycol dry photoresist is controlled according to the number of deposition cycles.

5. The preparation method according to claim 4, characterized in that, The molecular layer deposition reaction is carried out on a silicon or silicon dioxide substrate.

6. The preparation method according to claim 4, characterized in that, The deposition thickness is 0.1 nanometers per cycle.

7. The preparation method according to claim 4, characterized in that, The titanium source combines with the hydroxyl bonds on the diene glycol to form a titanium-diene-titanium structure.

8. A titanium-based diene glycol dry photoresist, characterized in that, It is prepared by any one of the preparation methods described in claims 1-9.

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