JP5619458B2 - Resist pattern forming method and mold manufacturing method - Google Patents

Description

  The present invention relates to a resist layer developer, a resist pattern forming method, and a mold manufacturing method, and more particularly, to a developer and a developing method when forming a pattern on a resist.

  Conventionally, in magnetic media used in hard disks and the like, a technique has been used in which magnetic particles are miniaturized, the magnetic head width is minimized, and data tracks on which information is recorded are narrowed to increase the recording density. On the other hand, there is an increasing demand for higher recording density, and in this magnetic medium, the magnetic influence between adjacent tracks cannot be ignored. For this reason, the conventional method has a limit in increasing the recording density.

  In recent years, a new type of media called patterned media in which data tracks of magnetic media are formed by magnetic separation has been proposed. This patterned medium is intended to achieve a higher recording density by removing (grooving) a magnetic material unnecessary for recording to improve signal quality.

  As a technique for mass-producing this patterned media, a pattern to be transferred (here, a master mold or a copy mold (also called a working replica) that is copied and copied once or multiple times using the master mold as a master mold) There is known an imprint technique (or nanoimprint technique) in which a patterned medium is produced by transferring to a magnetic medium). Hereinafter, the master mold and the copy mold are collectively referred to simply as a mold.

  For example, in Patent Document 1, a resist pattern forming method for manufacturing an imprint mold is described in which a resist layer is formed by applying a copolymer of α-methylstyrene and α-chloroacrylic acid as a resist on a quartz substrate. A technique is described in which the resist layer is subjected to electron beam drawing or exposure (hereinafter referred to as electron beam drawing), and the resist developer is acetic acid-n-amyl.

  As a related technology, a technology that uses a mixed solution of methyl isobutyl ketone and isopropanol as a resist developer composed of a copolymer of α-methylstyrene and α-chloroacrylic acid is known as a technology used in semiconductor manufacturing. (For example, refer to Patent Document 2).

  In addition, as a related technique, a technique using isopropanol as a resist developer made of a copolymer of α-methylstyrene and α-chloroacrylic acid is known as a technique used in patterned media production (for example, Non-Patent Document 1).

  Similarly, as related technology, but as a technology used in photo-image formation, especially in semiconductor manufacturing, as a resist developer composed of partially fluorinated bicyclic comonomers, Bertrell XF (registered trademark) Mitsui DuPont Fluorochemical Co., Ltd. is a fluorocarbon. (For example, see Patent Document 3).

JP 2009-226762 A JP 2000-039717 A Japanese translation of PCT publication No. 2002-525683

XiaoMin Yang et. al. J. et al. Vac. Sci. Technol. B 25 (6), Nov / Dec 2007 p. 2202

However, when developing a resist composed of a copolymer of α-methylstyrene and α-chloroacrylic acid with a developer composed of acetic acid-n-amyl, an electron beam drawn site (hereinafter referred to as resist dissolution) A line-and-space fine pattern with a width ratio of 1 to 2 between the region where the electron beam is not drawn (hereinafter referred to as the resist non-dissolved portion) and the resist layer. The line width of the resist-dissolved portion is about 26 nm, which is a resolution that is the limit for practical use (hereinafter referred to as resolution). In the case of using a mixed solution of methyl isobutyl ketone and isopropanol of Patent Document 2 in which 56 to 44 (volume mixing ratio) of methyl isobutyl ketone to isopropanol is used as the developer, the resolution described above is used. Was 20 nm.
Further, when the isopropanol of Non-Patent Document 1 was used as a developer, the resolution was improved to 14 nm.

Therefore, with the three types of developers, the resolution of the formed resist pattern was up to 14 nm.
On the other hand, the magnetic recording density aimed at practical use in Discrete Track Recording Media, which is one of patterned media, is generally 1 TeraBit / inch ² and the required track pitch is 50 nm. In other words, the resolution in a line-and-space pattern with a width ratio of 1 to 2 is approximately 17 nm. Similarly, in order to achieve a higher magnetic recording density of about 1.5 TeraBit / inch ² , the track pitch required for that is about 33 nm, that is, in a line-and-space pattern with a width ratio of 1: 2. The resolution is approximately 11 nm.

Therefore, it is required to achieve a higher resolution for the resolution.
The structure formed in the resist layer formed by the resist dissolving portion and the resist non-dissolving portion is referred to as a resist pattern.

  SUMMARY OF THE INVENTION An object of the present invention has been made in view of the above circumstances, and a resist layer developer, a resist pattern forming method, and a mold manufacturing that provide a desired high resolution for a resist layer having a predetermined composition. It is to provide a method.

The first aspect of the present invention is used when developing a resist layer that contains a polymer of α-chloromethacrylate and α-methylstyrene and that does not contain fluorine by drawing or exposing it to an energy beam. A resist layer developer comprising: a solvent having a dissolution rate of a resist non-dissolved portion (site not drawn or exposed) of less than about 0.5 mm per hour. It is.
The second aspect of the present invention is used when developing a resist layer that contains a polymer of α-chloromethacrylate and α-methylstyrene and that does not contain fluorine by drawing or exposing it to an energy beam. A resist layer developer comprising a solvent containing a fluorocarbon.
In a third aspect of the present invention, a step of forming a resist layer containing a polymer of α-chloromethacrylate and α-methylstyrene and not containing fluorine on a substrate, and irradiating the resist layer with an energy beam A step of drawing or exposing a predetermined pattern shape, and a step of developing the drawn or exposed resist layer with the developer according to the first or second aspect of the invention. This is a resist pattern forming method.
According to a fourth aspect of the present invention, there is provided the developer according to the third aspect, wherein the developer has a CF ₃ group at one or both ends and a (CFX) group (X is F or H). It is characterized by having.
According to a fifth aspect of the present invention, in the invention described in the third or fourth aspect, the developer is CF _3- (CFX) _n -CF ₃ (X is F or H, and n is a natural number). It is characterized by being.
According to a sixth aspect of the present invention, in the invention according to any one of the third to fifth aspects, the drawing or exposure step is a step of performing electron beam drawing, and the resist layer is sensitive to an electron beam. It is a resist.
According to a seventh aspect of the present invention, there is provided a step of forming a resist layer containing a polymer of α-chloromethacrylate and α-methylstyrene on a substrate and not containing fluorine and sensitive to an electron beam, A step of performing electron beam drawing on the layer, and a step of developing the drawn or exposed resist layer with a developer composed of CF _3- (CFX) _n -CF ₃ (X is F or H, and n is a natural number) And a method of forming a resist pattern.
According to an eighth aspect of the present invention, there is provided a step of forming a resist layer containing a polymer of α-chloromethacrylate and α-methylstyrene on a substrate and not containing fluorine, and irradiating the resist layer with an energy beam. Thus, there is provided a mold manufacturing method comprising a step of drawing or exposing a predetermined pattern shape and a step of developing the drawn or exposed resist layer with a developer containing fluorocarbon. .

  According to the present invention, a resist layer having a predetermined composition can be provided with a higher resolution in order to form a resist dissolution portion with a developer after drawing or exposure, that is, to form a resist pattern. it can.

It is a cross-sectional schematic diagram for demonstrating the manufacturing process of the mold which concerns on this embodiment. It is the figure which described the relationship between the exposure amount and resolution required for resist melt | dissolution of the electron beam drawing part in an Example and a comparative example, ie, resist pattern formation. It is a photograph which shows the result of having observed the resist pattern in the middle of preparation of the sample (mold) in an Example and a comparative example using the scanning electron microscope.

  As described in Patent Document 3, a fluorocarbon developer is used for a partially fluorinated resist (that is, a fluororesin). Thus, conventionally, the developer has been selected so that the dissolution rate in the resist is increased.

  However, the present inventors have found that the resolution can be increased by selecting the developer to lower the dissolution rate as opposed to selecting the developer to increase the dissolution rate. .

  Based on this knowledge, the present inventors have adopted Vertrel XF, which is a fluorocarbon, as a developer for a resist layer that does not contain fluorine. As a result, it has been found that a resist pattern with a desired high resolution can be formed.

<Embodiment>
Hereinafter, an embodiment of the present invention will be described based on FIG. 1 which is a schematic cross-sectional view for explaining a manufacturing process of a master mold.

(Preparation of substrate)
First, a substrate 1 that will eventually become a master mold 20 is prepared (FIG. 1A).

  The substrate in this embodiment is made of a metal such as quartz, sapphire, or Si, plastic, ceramic, or a combination thereof, and any material or structure can be used as long as it can be used as the master mold 20.

  In the present embodiment, description will be made using a substrate 1 made of wafer-shaped quartz. Hereinafter, the substrate 1 made of quartz having a wafer shape is simply referred to as a substrate 1. Here, the substrate 1 may have a shape other than the wafer shape, and is processed into a rectangular shape, a polygonal shape, a semicircular shape when viewed from the plane (upper surface), or a rectangular shape or a trapezoidal shape when viewed from the side surface. Any substrate may be used as long as it has a shape that can be accurately and stably fixed as a mold to the imprint apparatus. Further, the main surface may have a platform terrain (mesa structure or pedestal) whose peripheral edge is slightly lower than the pattern forming region of the mold main surface.

(Formation of hard mask layer on substrate)
First, the substrate 1 (FIG. 1A) that has been appropriately polished and cleaned as necessary is introduced into a sputtering apparatus. In this embodiment, a target made of chromium (Cr) is sputtered with argon gas and nitrogen gas to form a hard mask layer 2 made of chromium nitride (FIG. 1B).

  The hard mask layer 2 in the present embodiment is composed of a single layer or a plurality of layers, and the hard mask layer 2 in a portion corresponding to a groove (hereinafter referred to as a groove portion) of the resist pattern 4 described later is removed by etching. After that, it refers to a layer that acts as a mask material when the substrate 1 is etched to form a groove portion, and can protect portions other than the groove portion. Here, the hard mask layer 2 preferably has good adhesion to the resist layer 3 containing a polymer of α-chloromethacrylate and α-methylstyrene. The hard mask layer 2 preferably has good etching selectivity with the resist layer 3 containing a polymer of α-chloromethacrylate and α-methylstyrene. Further, the film thickness of the hard mask layer 2 at this time is preferably a thickness that remains until etching for forming a groove in the substrate 1 is completed.

(Formation of resist layer)
In the present embodiment, the substrate 1 on which the hard mask layer 2 is formed is appropriately washed, and after performing dehydration baking before resist application or formation of an adhesion auxiliary layer as necessary for improving adhesion. As shown in FIG. 1C, a resist containing a polymer of α-chloromethacrylate and α-methylstyrene and not containing fluorine is applied to the substrate 1 on which the hard mask layer 2 is formed, A resist layer 3 is formed. As a coating method, in this embodiment, the resist solution is dropped onto the main surface of the substrate 1 on which the hard mask layer 2 is formed, and then the substrate 1 is rotated at a predetermined rotational speed to form the resist layer 3. A spin coating method is used. Next, the substrate 1 on which the resist layer 3 is spin-coated is baked on a hot plate at a predetermined temperature and time, and then transferred onto a cooling plate kept at room temperature (22.5 ° C.), for example, and cooled. The resist layer 3 was formed by processing and drying.
Here, when the groove can be formed by etching the substrate 1 using the resist pattern as a mask material without requiring the hard mask layer 2, the resist layer 3 may be directly formed on the substrate 1. In this case, the resist layer 3 may be provided on the substrate 1 after the dehydration baking process or the formation of the adhesion auxiliary layer.

This resist may be any resist that does not contain fluorine and has reactivity when drawn or exposed by irradiation with an energy beam. Specifically, it may be a resist that needs to be developed with a developer, and may be a resist having sensitivity to ultraviolet rays, X-rays, electron beams, ion beams, proton beams, and the like. In this embodiment, a case where electron beam drawing is performed will be described.
At this time, a conductive agent for preventing charge-up may be applied on the resist layer 3.
In addition, the thickness of the resist layer 3 at this time is preferably such a thickness that the resist layer remains until etching of the hard mask layer 2 formed on the substrate 1 is completed. This is because etching to the hard mask layer 2 removes not only the portion corresponding to the resist dissolution portion formed in the resist layer 3 but also the resist layer 3 in the resist non-dissolution portion.

(Pattern drawing)
Next, a desired pattern is drawn on the resist layer 3 using an electron beam drawing apparatus.
This fine pattern may be in the micron order, but may be in the nano order from the viewpoint of the performance of electronic devices in recent years, and this is preferable in view of the performance of the final product.
In the present embodiment, a case will be described in which the resist layer 3 is a positive resist, and the portion drawn by the electron beam serves as a resist dissolution portion, and thus corresponds to the groove portion of the mold 20.

(developing)
After drawing a desired fine pattern with an electron beam, as shown in FIG. 1D, the resist layer 3 is developed with a predetermined developer, and the portion of the resist layer 3 on which the electron beam is drawn (resist dissolving portion) is removed. Then, a resist pattern 4 corresponding to a desired fine pattern is formed.

  Here, in the present embodiment, the drawn resist layer is developed with a developer containing a solvent A containing fluorocarbon which is a solvent having a dissolution rate of a resist non-dissolved portion of less than about 0.5% per hour as a developer. 3 is developed, that is, the resist layer in the resist dissolving portion is dissolved and removed.

In the present embodiment, a developer using CF ₃ —CFH—CFH—CF ₂ —CF ₃ (Bertrel XF (registered trademark, Mitsui, DuPont Fluorochemical Co., Ltd.), hereinafter also referred to as Compound Y) as the solvent A is used. The case where it was used for is described.

Specific examples of the development process for the resist layer 3 include the following methods.
That is, the hard mask layer 2 and the resist layer 3 are provided, and the substrate 1 on which a desired pattern is drawn with an electron beam is rotated at a predetermined rotational speed. Then, the developer is supplied dropwise from above the substrate 1. At this time, the developer may be at room temperature or may be maintained at a predetermined temperature. During the dropping of the developer, dissolution of the resist dissolving portion by the developer occurs.
In addition, even after the dissolution of the resist dissolving portion is completed, the developer containing the resist melt is kept by dripping the developer excessively while rotating the substrate 1. Flows down from the outer edge of the substrate. Further, by continuing to dripping the developer excessively while rotating the substrate 1, the developer containing the resist solution is replaced with the developer not containing the resist solution, and a clean resist pattern is formed. .

The solvent A may be any of fluorocarbon, perfluorocarbon, fluoroether, or a mixture thereof. That is, the dissolution rate of the resist non-dissolved portion (the portion where the electron beam is not drawn) of the resist layer containing a polymer of α-chloromethacrylate and α-methylstyrene and not containing fluorine is less than about 0.5% per hour. If it is good. By using the solvent A, the following effects can be expected. Solvent A composed of either fluorocarbon, perfluorocarbon, or fluoroether, or a mixture thereof includes a polymer of α-chloromethacrylate and α-methylstyrene and has a dissolution rate in a resist layer that does not contain fluorine. Is an extremely low poor solvent. By using a poor solvent, the dissolution rate of the resist layer 3 as a whole developer can be lowered. By doing so, unnecessary dissolution of the resist non-dissolved part due to the excessively high dissolution rate can be suppressed, and as a result, the resolution can be improved. In addition, the solvent A composed of any one of fluorocarbon, perfluorocarbon, fluoroether, or a mixture thereof has relatively low surface tension and viscosity. Therefore, it is easy to enter a very fine gap, and even when the electron beam drawing portion (resist dissolving portion) is extremely fine, the resist layer can be dug while being dissolved, and a nano-order extremely fine resist pattern can be formed.

Further, considering that the solvent A listed here lowers the surface tension, CF _3- (CX) _n -CF ₃ (X is a mixture of F or H, and n is a natural number) (that is, fluorocarbon), CF _3- (CX) _n -CF ₃ (X is F and n is a natural number, hereinafter referred to as Compound A) (ie, perfluorocarbon) (hereinafter referred to as Compound B), or CF _3- (CX) _m —O— (CX) _n -CX ₃ (X is F or H or a mixture of F and H, and m and n are integers) (that is, fluoroether, hereinafter referred to as Compound C), or Compound A and B or A And C, or compound B and compound C, or a mixture of compounds A, B, and C may be used. The dissolution rate of the resist non-dissolved portion (portion where electron beam is not drawn) of the resist layer containing a polymer of α-chloromethacrylate and α-methylstyrene and not containing fluorine is less than about 0.5% per hour. It may be a solvent or a mixed solution of a plurality of solvents.

(rinse)
Thereafter, immediately after the supply of the developer is stopped, the rinse agent is supplied dropwise from above the substrate 1 while rotating the substrate 1 in order to wash away the developer.
It is preferable that the rinsing agent is supplied dropwise before the developer supply is stopped. By doing so, it is possible to prevent the developer from being instantly replaced with the rinse agent, and the resist melt remaining in the developer staying on the substrate to be precipitated again and become dirty.
This rinsing agent has a lower dissolution rate of the resist non-dissolved portion (portion where the electron beam is not drawn) of the resist layer with respect to the solvent A as the developer, and is poor in wettability with the resist layer. A solvent is preferred. Further, by using a solvent having a surface tension equal to or smaller than that of the solvent A as a developer as the rinse agent, pattern collapse in the subsequent drying process can be prevented or reduced.
If an appropriate rinse agent is not found, the processing time with the developer A may be extended as long as the resist pattern quality can be maintained. Alternatively, the rinsing process may be omitted.

(Dry)
A drying process is performed on the substrate 1 that has been subjected to the above-described rinsing process or the substrate 1 that has not been rinsed. In this drying process, the substrate 1 is rotated at a predetermined number of revolutions after stopping the dripping supply of the rinsing agent after the rinsing process, or after stopping the dripping supply of the developer if the rinsing process is omitted. By doing. As a result, the rinse agent or developer flows down from the outer edge of the substrate or evaporates due to centrifugal force. Thus, the substrate 1 with the hard mask layer 2 on which the resist pattern 4 composed of the desired resist-dissolved portion and the resist non-dissolved portion is formed is obtained.
It is to be noted that, in order to remove the developer or rinse agent remaining in the formed resist pattern 4 and to improve the adhesion between the resist pattern 4 and the hard mask layer 2, drying is performed as necessary. A baking process may be performed following the process.

(Descum of resist pattern: first etching)
Thereafter, the substrate 1 with the hard mask layer 2 on which the resist pattern 4 is formed is introduced into a dry etching apparatus. Then, first etching with a mixed gas of oxygen gas and argon (Ar) gas is performed to remove the residue (scum) of the resist dissolution portion. Here, instead of oxygen gas, for example, fluorine-based gas such as CH ₄ may be used. Further, helium (He) may be added.

(Hard mask layer etching: second etching)
Subsequently, after exhausting the gas used in the first etching, the second etching is performed with a mixed gas composed of chlorine gas and oxygen gas, and the hard mask layer exposed by the development process and the first etching process is performed. 2 is removed.
Thus, as shown in FIG. 1 (e), the groove processing corresponding to the resist pattern 4 is performed on the hard mask layer 2 on the substrate 1.
Note that the etching end point at this time is determined by using, for example, a reflection optical end point detector or a plasma monitor.

(Substrate etching: third etching)
Subsequently, after exhausting the gas used in the second etching, a third etching using a fluorine-based gas is performed on the substrate 1.

  Thus, as shown in FIG. 1 (f), the groove 10 corresponding to the resist pattern 4 is processed on the substrate 1, and the hard mask layer 2 remaining except the groove and the mold 10 before the remaining resist pattern 4 is removed are formed. Produced.

Note that as the fluorine-based gas used here, C _x F _y (for example, CF ₄ , C ₂ F ₆ , C ₃ F ₈ ), CHF ₃ , a mixed gas thereof, or a rare gas (He, Ar, Xe, etc.) are included. In the etching to the substrate 1, when the substrate 1 is a quartz or Si wafer and the pattern to be formed is micro order, wet etching using hydrofluoric acid may be performed.

(Removal of resist pattern)
Subsequently, the resist pattern 4 remaining after the third etching is removed by a resist stripper made of a mixed solution of sulfuric acid and hydrogen peroxide solution, and the resist pattern 4 is completely stripped.
Specifically, the substrate 1 is immersed in the resist stripper for a predetermined time, and then the resist stripper is washed away with a rinse agent (in this case, room temperature or heated pure water). Next, the substrate 1 is dried by the same method as the drying process.
In addition, as a resist remover used here, in addition to the above-mentioned mixed solution of sulfuric acid and hydrogen peroxide solution, an organic solvent (in the case of a resist containing a polymer of α-chloromethacrylate and α-methylstyrene, anisole or N , N-dimethylacetamide (ZDMAC (manufactured by Nippon Zeon Co., Ltd.)), ozone water, etc. Any compound may be used as long as it is a compound that can swell and dissolve or chemically decompose and remove the resist. May be heated to increase the resist stripping / removing capability, or may be an ashing process using oxygen plasma.
The resist pattern 4 may be removed after the second etching process and before the third etching process.

(Removal of hard mask layer: fourth etching)
Subsequently, the hard mask layer 2 patterned corresponding to the resist pattern 4 remaining on the mold 10 before removing the remaining hard mask layer 2 is dry-etched by the same method as the first etching. The process of peeling and removing is performed. If there is a chemical that can dissolve and remove the hard mask layer, the hard mask layer may be removed by wet etching.

  After the above steps, the substrate 1 is cleaned if necessary. In this way, a master mold 20 as shown in FIG. 1G is completed.

  Note that only one of the etchings may be wet etching, and other etchings may be dry etching, or all etchings may be wet etching or dry etching. Further, when the pattern size is in the micron order, wet etching may be introduced according to the pattern size, such as wet etching at the micron order stage and dry etching at the nano order stage.

In the present embodiment as described above, the following effects can be obtained.
That is, a developer containing a solvent A containing a fluorocarbon, which is a solvent having a dissolution rate of the resist non-dissolved part of less than about 0.5% per hour, contains a polymer of α-chloromethacrylate and α-methylstyrene, and By using it for a resist layer not containing fluorine, a resist pattern can be formed with a desired high resolution.

In the present embodiment, description has been made focusing on a resist containing a polymer of α-chloromethacrylate and α-methylstyrene and not containing fluorine. However, the technical idea of the present invention is applied to this type of resist. It is speculated that it is not limited. That is, it is presumed that the solvent A constituting the developer for the resist can be set each time depending on the type of resist. Further, even when the fluorocarbon listed in the present embodiment is not used, if another type of compound is used for the solvent A, the effects described in the present embodiment may be obtained. Furthermore, it is speculated that another type of compound can also be used as the rinsing liquid without using the fluorocarbon mentioned in the present embodiment in the rinsing liquid.
The technical idea of the present invention has been intensively studied by the inventors.

  Further, the resist pattern forming method and the mold manufacturing method in the first embodiment can be suitably applied to the following uses other than the mold manufacturing. For example, a photomask for a semiconductor device, semiconductor manufacturing, a micro electro mechanical system (MEMS) , Sensor elements, optical disks, optical components such as diffraction gratings and polarizing elements, nanodevices, organic transistors, color filters, microlens arrays, immunoassay chips, DNA separation chips, microreactors, nanobiodevices, optical waveguides, optical filters, photo It can be widely applied to the production of nick crystals.

  As mentioned above, although embodiment which concerns on this invention was mentioned, said disclosure content shows exemplary embodiment of this invention. The scope of the present invention is not limited to the exemplary embodiments described above. Regardless of whether it is explicitly described or suggested in this specification, those skilled in the art will make various modifications to the embodiments of the present invention based on the disclosure of this specification. Can be implemented.

  Next, an Example is shown and this invention is demonstrated concretely. Of course, the present invention is not limited to the following examples.

<Example 1>
In this example, a wafer-shaped synthetic quartz substrate (outer diameter 150 mm, thickness 0.7 mm) was used as the substrate 1 (FIG. 1A).
First, the substrate 1 was introduced into a sputtering apparatus, and a target made of chromium (Cr) was sputtered with argon gas and nitrogen gas to form a hard mask layer 2 made of chromium nitride having a thickness of 2 nm (FIG. 1B). )). The substrate 1 on which the hard mask layer was formed was baked on a hot plate at 200 ° C. for 10 minutes to perform a dehydration baking process. Thereafter, the substrate 1 was placed on a cooling plate kept at room temperature (22.5 ° C.) to cool the substrate 1.

  Next, the substrate 1 on which the hard mask layer was formed was set on a resist coater. ZEP520A-7 (manufactured by Nippon Zeon Co., Ltd.), which is a polymer of α-chloromethacrylate and α-methylstyrene, is used as a solvent and anisole for ZEP520A-7 (manufactured by Nippon Zeon Co., Ltd.). The resist solution was prepared in advance by diluting ZEP520A-7 to ZEP-A so that the volume mixing ratio was 1: 3. About 3 ml of this resist solution was dropped on the substrate 1, and then the substrate 1 was rotated at 4000 rpm for 45 seconds.

  After spin coating of the resist solution, this substrate 1 is baked on a hot plate at 200 ° C. for 15 minutes (baking after coating) to remove unnecessary residual solvent in the formed resist layer, and have a thickness of 30 nm. A resist layer made of ZEP520A was obtained.

  Then, using a point beam type electron beam drawing machine with an accelerating voltage of 100 kV, the line-and-width ratio between the electron beam drawing portion (resist dissolving portion) and the electron beam non-drawing portion (resist non-dissolving portion) is 1: 2.・ Draw a space pattern. At this time, electron beam drawing was performed by changing the width of the portion corresponding to the resist dissolution portion every 3 nm in the range of the resist dissolution portion in the range of 8 to 30 nm.

Thereafter, the resist layer of the substrate 1 was developed with the developer according to this example. As the developer according to this example, CF ₃ —CFH—CFH—CF ₂ —CF ₃ (Bertrel XF (registered trademark, manufactured by Mitsui DuPont Fluorochemical Co., Ltd.)) was used.

  During this development processing, the substrate 1 was kept rotating at 250 rpm. Then, a developer was dropped from above the substrate 1 for 30 seconds. At this time, the developer was kept at room temperature (22.5 ° C.).

  Then, after the supply of the developer was stopped, the substrate 1 was appropriately rotated at 1500 rpm to perform a drying process. Thus, a sample according to the example was manufactured.

  At this time, there is no significant residue in the portion that is originally a resist dissolving portion, there is no sticking of the adjacent resist undissolved portion, and furthermore, there is no curve or meandering of the pattern greatly deviating from a predetermined drawing pattern portion, In addition, there is no protrusion or biting that deviates significantly from the predetermined drawing pattern portion, and the width ratio between the electron beam drawing portion (resist dissolving portion) and the electron beam non-drawing portion (resist non-dissolving portion) is approximately The line width of the resist dissolution part that is normally resolved, which is 1: 2, was measured, and this line width was determined as the resolution that would be a limit in practical use. Moreover, the exposure amount when the resolution which becomes the limit in practical use was obtained was determined as the necessary exposure amount.

<Example 2>
In Example 1, only Bartrel XF was used as a developer. On the other hand, in Example 2, the volume mixing ratio of Bartrel XF and isopropanol was 5 to 3, that is, the volume mixing ratio of isopropanol to (Bertrel XF + isopropanol) was 37.5%. A sample was prepared in the same manner as in Example 1 except for this.

<Comparative Examples 1-3>
In Example, the developer was only Bertrell XF or a mixed liquid of Bertrell XF and isopropanol. In Comparative Example 1, the developer was only ZED-N50 (made by Nippon Zeon Co., Ltd.) composed of acetic acid-n-amyl, In Comparative Example 2, the developer is ZMD-C (manufactured by Nippon Zeon Co., Ltd.) consisting of a mixture of methyl isobutyl ketone and isopropanol (volume mixing ratio is 56:44), and in Comparative Example 3, the developer is only isopropanol. A sample was prepared in the same manner as in Example 1 except that.

<Evaluation>
Samples obtained in Examples and Comparative Examples (Quartz substrate with a resist pattern (a chromium nitride film is formed as a hard mask layer directly on the quartz substrate, and a polymer of α-chloromethacrylate and α-methylstyrene is formed thereon) Evaluation was made on a resist pattern comprising ZEP520A, which is a resist that does not contain fluorine. The results are shown in FIGS.
FIG. 2 is a diagram describing the relationship between the resolution that is the limit in practical use in Example 1 and Example 2 and the exposure amount necessary for resist dissolution.
FIG. 3 is a photograph obtained by observing the resist pattern, which is in the process of producing samples (molds) in Examples 1-2 and Comparative Examples 1-3, using a scanning electron microscope.
Table 1 shows a developer of Examples and Comparative Examples after a resist layer made of ZEP520A which is a polymer of α-chloromethacrylate and α-methylstyrene and does not contain fluorine is formed on a substrate. The film thickness of the resist layer was measured with a spectral reflection type film thickness meter before and after that, and the dissolution rate per hour of the resist layer (corresponding to a non-dissolved part) was obtained.

In Examples 1 and 2, as shown in FIGS. 2 and 3A and 3B, a resist pattern having a high resolution of 11 nm, which is better than Comparative Examples 1 to 3, was obtained. In particular, when the volume mixing ratio of isopropanol to (Bertrel XF + isopropanol) is 37.5% (that is, in Example 2), the required exposure amount in the case of Example 1 is about 725 μC / cm ² compared with the required exposure amount of 1800 μC / cm ^2. A resist pattern with a high resolution of 11 nm was obtained with a low exposure of cm ² (about 40%).
As a result, in Examples 1 and 2, the resolution was improved as compared with Comparative Examples 1 to 3.

On the other hand, as shown in FIG. 2 and FIGS. 3C to 3E, in Comparative Example 1, the resolution is 26 nm and the required exposure amount is 120 μC / cm ² , and the required exposure amount is low, but it is practical compared to the examples. The resolution, which is the limit in use, was low (FIG. 2 (Comparative Example 1), FIG. 3 (c)).
In Comparative Example 2, the resolution is 20 nm and the necessary exposure amount is 350 μC / cm ^{2. As} in Comparative Example 1, the necessary exposure amount can be low, but the resolution that is the limit in practical use is that in Example 1 and 2 (Fig. 2 (Comparative Example 2), Fig. 3 (d)).
As described above, a resolution of 11 nm (line-and-space with a width ratio of 1: 2) is required for a track pitch of about 33 nm in the DTRM necessary to achieve the magnetic recording density “1.5 TeraBit / inch ² ”. (Pattern) is not obtained in Comparative Example 1, Comparative Example 2 and Comparative Example 3 (FIG. 2 (Comparative Example 3) and FIG. 3 (e)).

DESCRIPTION OF SYMBOLS 1 Substrate 2 Hard mask layer 3 Resist layer 4 Resist pattern 10 Residual hard mask layer and resist layer removal mold 20 Mold (master mold)

Claims (6)

Forming a resist layer containing a polymer of α-chloromethacrylate and α-methylstyrene and not containing fluorine on a substrate;
Irradiating the resist layer with an energy beam to draw or expose a predetermined pattern shape; and
Developing the drawn or exposed resist layer with a developer containing fluorocarbon ; and
A method of forming a resist pattern, comprising: 2. The resist pattern forming method according to claim 1 , wherein the developer has a CF ₃ group at one or both ends and a (CFX) group (X is F or H) at the other end. The _{developer, CF 3 - (CFX) n} -CF 3 (X is F or H and n is a natural number) The method of forming a resist pattern according to claim 1 or 2, characterized in that a. The drawing or exposure step is a step of performing electron beam drawing,
The resist layer forming method of a resist pattern according to any one of claims 1 to 3, characterized in that a resist having sensitivity to electron beam. Forming a resist layer sensitive to an electron beam on a substrate, which contains a polymer of α-chloromethacrylate and α-methylstyrene and does not contain fluorine;
Performing electron beam drawing on the resist layer;
Developing the drawn or exposed resist layer with a developer comprising CF _3- (CFX) _n -CF ₃ (X is F or H and n is a natural number);
A method of forming a resist pattern, comprising: Forming a resist layer containing a polymer of α-chloromethacrylate and α-methylstyrene and not containing fluorine on a substrate;
Irradiating the resist layer with an energy beam to draw or expose a predetermined pattern shape; and
Developing the drawn or exposed resist layer with a developer containing fluorocarbon; and
The manufacturing method of the mold characterized by including.