Preparation method of nanoimprint template with high aspect ratio

Abstract

The invention relates to the technical field of nanoimprint, in particular to a preparation method of a nanoimprint template with a high aspect ratio, which comprises the following steps of: forming patterns with the spacing of 110-200nm and the width of 110-200nm on photoresist by using a deep ultraviolet lithography technology; transferring the pattern on the photoresist to the oxide layer through an etching process; and carrying out oxide layer deposition on the oxide layer with the transferred pattern, and preparing the high aspect ratio nanoimprint template by controlling deposition conditions and process parameters. According to the method, the large-size pattern is formed through optical exposure etching, and then the pattern is corrected, so that the efficient and accurate high-aspect-ratio pattern preparation method is realized. The method has a wide application prospect in the fields of semiconductor manufacturing, micro-nano processing and the like. For example, in semiconductor manufacturing, devices such as transistors and memories with high aspect ratios can be prepared by using the method; in the micro-nano processing, the method can be used for preparing micro-nano devices, sensors and the like with complex structures.

Description

Technical Field

[0001] The invention relates to the technical field of nanoimprinting, and in particular to a method for preparing a nanoimprinting template with a high aspect ratio. Background Art

[0002] With the rapid development of nanotechnology, the preparation of high-precision and high-resolution nanoscale patterns has become an important demand in scientific research and industry. Among the many nano-pattern preparation technologies, nanoimprint technology has attracted widespread attention due to its significant advantages such as simple process, low cost, large-scale production and high pattern resolution. This technology uses an imprinting mold to imprint the photoresist, and combined with subsequent process steps, successfully replicates the micro-nano structure on the mold onto the material to be processed, achieving the preparation of high-precision patterns.

[0003] As a key material in nanoimprint technology, photoresist is usually composed of single molecules or polymers and has the characteristics of thermal curing or UV curing. During the imprinting process, the curing method of the photoresist and the adhesion between it and the imprinting mold must be precisely controlled to ensure the best imprinting effect. This feature gives nanoimprint technology a unique advantage in preparing complex and fine nano patterns.

[0004] However, the production of high-resolution templates, the core of nanoimprint technology, faces certain challenges. At present, high-resolution templates are mainly produced by direct electron beam exposure. The electron beam exposure method uses an electron beam to irradiate the surface of the template material and forms the desired pattern by precisely controlling the position and intensity of the electron beam. Although this method can produce high-precision nano patterns, it has the following two significant disadvantages:

[0005] 1. Low efficiency of electron beam exposure and long production cycle: During the electron beam exposure process, the surface of the template material needs to be scanned point by point to form the required pattern. This process is time-consuming, resulting in a long template production cycle and unable to meet the needs of fast and efficient production. At the same time, low efficiency also limits the large-scale production of templates and increases production costs.

[0006] 2. Electron beam glue has poor etching resistance and cannot achieve high aspect ratio pattern etching: After electron beam exposure, the template material needs to be developed, etched, and other processes to obtain the final nanoimprint template. However, the commonly used electron beam glue has poor etching resistance and cannot withstand the etching process of high aspect ratio patterns, resulting in a decrease in the pattern quality of the template and failing to meet the preparation requirements of high-precision nano patterns.

[0007] In summary, although nanoimprint technology has significant advantages in preparing high-precision nanopatterns, the preparation of high-resolution templates faces challenges such as low efficiency and poor etching resistance. Therefore, developing an efficient, low-cost, high-quality method for preparing high-resolution templates is of great significance to promote the further development of nanoimprint technology.

[0008] In view of this, the present invention is proposed. Summary of the invention

[0009] The object of the present invention is to provide a method for preparing a nanoimprint template with a high aspect ratio, which can realize the preparation of an imprint template with a high aspect ratio and has the advantages of high efficiency, high quality and low cost.

[0010] The present invention provides a method for preparing a high aspect ratio nanoimprint template, comprising the following steps:

[0011] S1, deep ultraviolet lithography;

[0012] S2, graphic transfer;

[0013] S3, oxide layer deposition.

[0014] The present invention first forms a large-size pattern by optical exposure etching to achieve the construction of a small line width structure, and then corrects the pattern and reduces its size to achieve the preparation of a high aspect ratio pattern. The method effectively combines the high efficiency of deep ultraviolet lithography and the accuracy of oxide layer deposition. The method is simple and efficient, and provides a new way to prepare high aspect ratio patterns.

[0015] As a preferred embodiment of the present technical solution, step S1 includes: using deep ultraviolet lithography technology to form a pattern with a spacing of 110-200nm and a width of 110-200nm on the photoresist.

[0016] In the present invention, deep ultraviolet lithography is firstly used to form a pattern with a certain spacing and width on the photoresist. The deep ultraviolet lithography not only improves the efficiency of pattern preparation and reduces production costs, but also effectively avoids the inefficient electron beam exposure.

[0017] As a preferred embodiment of the present technical solution, step S2 includes: transferring the pattern on the photoresist to the oxide layer through an etching process.

[0018] The present invention further adopts an etching process to transfer the pattern on the photoresist to the oxide layer. Since the thickness of the photoresist can reach 4000 Å, it is completely feasible to transfer to an oxide layer with a thickness of 3000 Å or higher. The etching process can effectively ensure the accurate transfer of the pattern and avoid deformation or error during the transfer process.

[0019] As a preferred embodiment of the present technical solution, step S3 includes: depositing an oxide layer on the oxide layer to which the pattern has been transferred, and preparing a high aspect ratio nanoimprint template by controlling deposition conditions and process parameters, wherein the deposition thickness is between 300-600 nm.

[0020] Finally, the present invention deposits an oxide layer on the oxide layer to which the pattern has been transferred, thereby realizing a nanoimprint template with a high aspect ratio. The oxide layer deposition technology has the characteristics of high precision and strong controllability, and can prepare patterns with complex structures and high aspect ratios.

[0021] Studies have shown that the method of the present invention can realize the preparation of structural patterns with a width of 30nm and a depth-to-width ratio of 1:10. Compared with the electron beam exposure method, it has the advantages of high preparation efficiency and low production cost.

[0022] As a preferred embodiment of the present technical solution, the photoresist is UV135, and the thickness of the photoresist is 3000-4000A. Since the thickness of the photoresist can reach 3000-4000A, the pattern can be transferred to an oxide layer with a height of 3000A or even 4000A.

[0023] As a preferred embodiment of the present technical solution, during pattern transfer, the etching process used is preferably dry etching, and during dry etching, it is necessary to control the etching rate to 38A / min, the pressure to 200mTorr-300mTorr, and the etching gas to be CF4 and CHF3.

[0024] As a preferred embodiment of the present technical solution, when the oxide layer is deposited, the deposited material includes any one of silicon dioxide, silicon nitride and amorphous silicon.

[0025] As a preferred embodiment of the present technical solution, in step S3, when the oxide layer is deposited, a deposition method includes any one of thermal oxidation and chemical vapor deposition.

[0026] When thermal oxidation is used, the temperature during the deposition process needs to be controlled to be 1100-1200° C. and the gas flow rate to be 10 L / min-30 L / min.

[0027] When chemical vapor deposition is used, the temperature during the deposition process needs to be controlled at 500-700°C, the pressure at 2.0 Torr-3.0 Torr, and the gas flow rate at 35 L / min.

[0028] The method for preparing a nanoimprint template with a high aspect ratio of the present invention has at least the following beneficial effects:

[0029] The present invention first uses deep ultraviolet lithography technology to form a pattern with a certain spacing and width on a photoresist; then, the pattern on the photoresist is transferred to an oxide layer through an etching process; finally, an oxide layer is deposited on the oxide layer to which the pattern has been transferred, and a high aspect ratio nanoimprint template can be prepared by controlling the deposition conditions and process parameters. The present invention realizes an efficient and accurate method for preparing a high aspect ratio pattern by using a method of optical exposure etching to form a large-size pattern and then correcting the pattern. The present invention effectively solves the problems of low exposure efficiency, long production cycle, poor etching resistance of electron beam colloid, and inability to achieve high aspect ratio pattern etching in the electron beam exposure method. The method has broad application prospects in the fields of semiconductor manufacturing, micro-nano processing, etc. For example, in semiconductor manufacturing, the method can be used to prepare devices such as transistors and memories with a high aspect ratio; in micro-nano processing, the method can be used to prepare micro-nano devices and sensors with complex structures. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] In order to more clearly illustrate the specific implementation methods of the present invention or the technical solutions in the prior art, the drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some implementation methods of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0031] Figure 1 It is a flow chart of the method for preparing a nanoimprint template with a high aspect ratio according to the present invention;

[0032] Figure 2 The silicon oxide pattern obtained after the pattern transfer of the present invention;

[0033] Figure 3 The nanoimprint template pattern with a depth-to-width ratio of 1:10 prepared in Example 1 of the present invention;

[0034] Figure 4 This is the nanoimprint template pattern prepared in the control example of the present invention.

[0035] Description of reference numerals:

[0036] 1: substrate; 2: photoresist; 3: oxide layer. DETAILED DESCRIPTION

[0037] The technical solution of the present invention will be clearly and completely described below in conjunction with the embodiments. Obviously, the described embodiments are part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0038] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as limiting the present invention.

[0039] In addition, the terms "first" and "second" are only used for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of the present invention, "multiple" means two or more, unless otherwise clearly and specifically defined. In addition, the terms "installed", "connected" and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal connection of two components. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0040] Figure 1 is a flow chart of the method for preparing a high aspect ratio nanoimprint template of the present invention, referring to Figure 1 The preparation process of is carried out as follows.

[0041] Example 1

[0042] This embodiment provides a method for preparing a high aspect ratio nanoimprint template, comprising the following steps:

[0043] S1. Using deep ultraviolet lithography technology, a pattern with a spacing of 180 nm and a width of 180 nm is formed on the photoresist;

[0044] S2, using dry etching process, and controlling the etching rate to 38A / min, the pressure to 250mTorr, the etching gas to CF4 and CHF3, transfer the pattern on the photoresist to the oxide layer ( Figure 2 is the silicon oxide pattern obtained after pattern transfer);

[0045] S3, using thermal oxidation method to deposit a 500nm oxide layer on the oxide layer to which the pattern has been transferred, wherein during thermal oxidation deposition, the temperature during the deposition process is controlled to be 1100-1200°C, and the gas flow rate is 10L / min-30L / min, to prepare a nanoimprint template with a high aspect ratio ( Figure 3 This is a nanoimprint template pattern with a depth-to-width ratio of 1:10 prepared in the embodiment).

[0046] Example 2

[0047] This embodiment provides a method for preparing a high aspect ratio nanoimprint template, comprising the following steps:

[0048] S1. Using deep ultraviolet lithography technology, a pattern with a spacing of 200 nm and a width of 200 nm is formed on the photoresist;

[0049] S2, using dry etching process, and controlling the etching rate to 38A / min, the pressure to 300mTorr, and the etching gas to CF4 and CHF3, to transfer the pattern on the photoresist to the oxide layer;

[0050] S3. A 600nm oxide layer is deposited on the oxide layer to which the pattern has been transferred by thermal oxidation. During thermal oxidation deposition, the temperature during the deposition process is controlled to be 1100-1200°C, and the gas flow rate is 10L / min-30L / min, so as to prepare a nanoimprint template with a high aspect ratio.

[0051] Example 3

[0052] This embodiment provides a method for preparing a high aspect ratio nanoimprint template, comprising the following steps:

[0053] S1. Using deep ultraviolet lithography technology, a pattern with a spacing of 110nm and a width of 110 is formed on the photoresist;

[0054] S2, using dry etching process, and controlling the etching rate to 38A / min, the pressure to 200mTorr, and the etching gas to CF4 and CHF3, to transfer the pattern on the photoresist to the oxide layer;

[0055] S3. A 300 Å oxide layer is deposited on the oxide layer to which the pattern has been transferred by thermal oxidation. During thermal oxidation deposition, the temperature during the deposition process is controlled to be 1100-1200°C, and the gas flow rate is 10L / min-30L / min, so as to prepare a nanoimprint template with a high aspect ratio.

[0056] Example 4

[0057] This embodiment provides a method for preparing a high aspect ratio nanoimprint template, comprising the following steps:

[0058] S1. Using deep ultraviolet lithography technology, a pattern with a spacing of 180 nm and a width of 180 nm is formed on the photoresist;

[0059] S2, using dry etching process, and controlling the etching rate to 38A / min, the pressure to 250mTorr, and the etching gas to CF4 and CHF3, to transfer the pattern on the photoresist to the oxide layer;

[0060] S3. A 500 nm oxide layer is deposited on the oxide layer to which the pattern has been transferred by chemical vapor deposition. During chemical vapor deposition, the temperature during the deposition process is controlled to be 500-700°C, the pressure is 2.0 Torr-3.0 Torr, and the gas flow rate is 35 L / min, so as to prepare a nanoimprint template with a high aspect ratio.

[0061] Example 5

[0062] This embodiment provides a method for preparing a high aspect ratio nanoimprint template, comprising the following steps:

[0063] S1. Using deep ultraviolet lithography technology, a pattern with a spacing of 200 nm and a width of 200 nm is formed on the photoresist;

[0064] S2, using dry etching process, and controlling the etching rate to 38A / min, the pressure to 300mTorr, and the etching gas to CF4 and CHF3, to transfer the pattern on the photoresist to the oxide layer;

[0065] S3. A 600 nm oxide layer is deposited on the oxide layer to which the pattern has been transferred by chemical vapor deposition. During chemical vapor deposition, the temperature during the deposition process is controlled to be 500-700°C, the pressure is 2.0 Torr-3.0 Torr, and the gas flow rate is 35 L / min, so as to prepare a nanoimprint template with a high aspect ratio.

[0066] Example 6

[0067] This embodiment provides a method for preparing a high aspect ratio nanoimprint template, comprising the following steps:

[0068] S1. Using deep ultraviolet lithography technology, a pattern with a spacing of 110 nm and a width of 110 nm is formed on the photoresist;

[0069] S2, using dry etching process, and controlling the etching rate to 38A / min, the pressure to 200mTorr, and the etching gas to CF4 and CHF3, to transfer the pattern on the photoresist to the oxide layer;

[0070] S3. A 300 nm oxide layer is deposited on the oxide layer to which the pattern has been transferred by chemical vapor deposition. During chemical vapor deposition, the temperature during the deposition process is controlled to be 500-700°C, the pressure is 2.0 Torr-3.0 Torr, and the gas flow rate is 35 L / min, so as to prepare a nanoimprint template with a high aspect ratio.

[0071] Comparison Example

[0072] This comparative example adopts the method of electron beam exposure to prepare the nanoimprint template, which specifically includes the following steps:

[0073] Prepare the template material to be exposed;

[0074] placing the template material in an electron beam exposure machine;

[0075] Design and input pattern information into the electron beam exposure machine;

[0076] Adjust the position and intensity of the electron beam to perform exposure;

[0077] After the exposure is completed, the template material is developed, etched, and processed to obtain the final nanoimprint template.

[0078] Figure 4 This is the nanoimprint template prepared in this control example. As can be seen from the figure, the aspect ratio of the nanoimprint template prepared in this control example can only reach 3.5:1.

[0079] It can be seen that compared with the electron beam exposure method, the present invention can not only prepare a nanoimprint template with a high aspect ratio, but also has the advantages of high efficiency, high quality and low cost.

[0080] In the above description, the technical details of patterning and etching of each layer are not described in detail. However, those skilled in the art should understand that various technical means can be used to form layers, regions, etc. of desired shapes. In addition, in order to form the same structure, those skilled in the art can also design methods that are not completely the same as the methods described above.

[0081] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for preparing a high aspect ratio nanoimprint template, characterized in that: The following steps are involved: S1, deep ultraviolet lithography; S2, graphic transfer; S3, oxide layer deposition.

2. The preparation method according to claim 1, characterized in that: Step S1 includes: using deep ultraviolet lithography technology to form a pattern with a spacing of 110-200nm and a width of 110-200nm on the photoresist.

3. The preparation method according to claim 1, characterized in that: Step S2 includes: transferring the pattern on the photoresist to the oxide layer through an etching process.

4. The preparation method according to claim 1, characterized in that: Step S3 includes: depositing an oxide layer on the oxide layer to which the pattern has been transferred, and preparing a nanoimprint template with a high aspect ratio by controlling deposition conditions and process parameters, wherein the deposition thickness is between 300-600 nm.

5. The preparation method according to claim 2, characterized in that: The photoresist is UV135, and the thickness of the photoresist is 3000-4000A.

6. The preparation method according to claim 3, characterized in that: The etching process is dry etching; During the dry etching, the etching rate is controlled to be 38A / min, the pressure is 200mTorr-300mTorr, and the etching gas is CF4 and CHF3.

7. The preparation method according to claim 4, characterized in that: In step S3, when the oxide layer is deposited, the deposited material includes any one of silicon dioxide, silicon nitride and amorphous silicon.

8. The preparation method according to claim 4, characterized in that: In step S3, when the oxide layer is deposited, the deposition method includes any one of thermal oxidation and chemical vapor deposition.

9. The preparation method according to claim 8, characterized in that: During the thermal oxidation, the temperature during the deposition process is controlled to be 1100-1200° C., and the gas flow rate is 10 L / min-30 L / min.

10. The preparation method according to claim 8, characterized in that: During the chemical vapor deposition, the temperature during the deposition process is controlled to be 500-700° C., the pressure to be 2.0 Torr-3.0 Torr, and the gas flow rate to be 35 L / min.

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