Pattern formation method
A pattern formation method comprises a process of forming a resist pattern with an opening that exposes a first region of a glass film arranged on a substrate through a base film; a process of forming a neutralization film above the glass film; a process of forming a directed self-assembly material layer containing a first segment and a second segment above the glass film; a process of microphase separating the directed self-assembly material layer to form a directed self-assembly pattern containing a first part that includes the first segment and a second part that includes the second segment; and a process of removing either the first part or the second part and using the other as a mask to process the base film.
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This application is based upon and claims the benefit of priority from Japanese Patent Application No. 2012-208276, filed Sep. 21, 2012, the entire contents of which are incorporated herein by reference.
FIELDEmbodiments described herein relate generally to a pattern formation method.
BACKGROUNDConventional lithography techniques used in the manufacturing process of semiconductor devices include the double patterning technique by ArF immersion exposure, EUV lithography, and nano imprints. The conventional lithography techniques have various problems, such as increased costs and decreased throughput caused by the refinement of patterns.
Under such conditions, application of DSA (directed self-assembly) to lithography techniques is expected. Since directed self-assembly is generated by spontaneous energy stability, this enables the formation of patterns with high dimensional accuracy. Especially for technologies using microphase separation of macromolecule block copolymer, periodic structures up to several hundred nanometers (nm) of various shapes may be formed with a simple coating and annealing process. Depending on the composition ratio of the macromolecule block copolymer, spherical shapes, cylindrical shapes, or lamellar shapes may be formed by changing the sizes based on the molecular weight, and a dot pattern, hole or pillar pattern, or a line pattern of various dimensions may be formed on a substrate.
In order to form a desired pattern in a wide range using DSA, a guide to control the generating position of the DSA polymer phase needs to be provided. A physical guide (grapho-epitaxy) has a relief structure with a phase-separation pattern formed on the surface. A chemical guide (chemical-epitaxy) is formed on the lower layer of the DSA material. Based on the surface energy difference, control of the forming position of the microphase separation pattern is achieved.
Several chemical guide formation methods are known; however, many of these guides contain physical steps with sizes up to 10 nm. This physical step makes it difficult to transcribe a microphase separation pattern on the lower layer of the processed film, which causes detrimental effects to the regularity of the phase separation.
Embodiments provide a pattern formation method that enables an increase in the flatness of a chemical guide and easily transcribes a microphase separation pattern onto a lower film.
In general, the embodiments are explained below based on the drawings presented in the figures.
According to one embodiment, a pattern formation method includes a process of forming a resist pattern with an opening that exposes a first region of a glass film onto the glass film arranged on a substrate through a film that is used for further processing; a process of forming a neutralization film above the glass film after removing the resist pattern; a process of forming a directed self-assembly material layer containing a first segment and a second segment above the glass film after removing the neutralization film; a process of microphase separating the directed self-assembly material layer to form a directed self-assembly pattern containing a first part that includes the first segment and a second part that includes the second segment; and a process of removing either the first part or the second part and using the other as a mask to process the film.
First EmbodimentThe pattern formation method based on the first embodiment will be described with reference to
First, as shown in
Here, it is desired that the surface of the SOG film 103 be hydrophobic and that a pure water (de-ionized water (DIW)) contact angle to be greater than or equal to 76 degrees (°). The contact angle of greater than or equal to 76° here is a contact angle of DIW on the film when the film has a median surface energy between that of a pure block copolymer of polystyrene (PS) film and that of a pure polymethyl methacrylate (PMMA) film. In the present embodiment, an SOG film having a DIW contact angle 83.0° is used. In the process shown in
Next, as shown in
Next, as shown in
Next, as shown in
Then, as shown in
Next, as shown in
Then, as shown in
After that, etching is performed and a line pattern is obtained by using the etching rate difference in PS and PMMA to selectively eliminate the first polymer part 107a or the second polymer part 107b in the directed self-assembly pattern 107 by, for instance, the oxygen plasma treatment. Then, the remaining first polymer part 107a or second polymer part 107b is used as a mask to process the first film 102. As a result, the line pattern is transcribed onto the first film 102.
In the present embodiment, the directed self-assembly material 106 is formed above a chemical guide (SOG film 103) having a high surface flatness. Consequently, a microphase separating pattern may be easily transcribed onto the first film (lower film) 102 that is further processed.
In this embodiment, the resist is narrowed by the O2 plasma treatment shown in
In the process shown in
The pattern formation method based on the second embodiment will be described with reference to
First, as shown in
Here, it is desired that the surface of the SOG film 203 be hydrophobic and that the pure water contact angle be greater than or equal to 76°. In the process shown in
Next, as shown in
Then, as shown in
Next, as shown in
Then, as shown in
Next, as shown in
Subsequently, a line pattern is obtained by using the etching rate difference in PS and PMMA to selectively eliminate the first polymer part 207a or the second polymer part 207b in the directed self-assembly pattern 207 by, for instance, an oxygen plasma treatment. Then, the remaining first polymer part 207a or second polymer part 207b is used as a mask to process the first film 202. As a result, a line pattern is transcribed onto the first film 202.
In the present embodiment, the directed self-assembly material 206 is formed above the chemical guide (SOG film 203) having high surface flatness. Consequently, a microphase separating pattern may be easily transcribed onto the first film (lower film) 202.
In addition, compared to the first embodiment, the present embodiment omits the oxidation treatment process (refer to
The pattern formation method based on the third embodiment will be described with reference to
First, as shown in
Here, the surface of the SOG film 303 is hydrophobic and a pure water contact angle is greater than or equal to 76°. In addition, the SOG film 303 has a higher hydrophobicity than that of the SOG film 203 in the second embodiment. In the process shown in
Next, as shown in
Then, as shown in
Next, as shown in
Subsequently, a line pattern is obtained by using the etching rate difference in PS and PMMA to selectively eliminate the first polymer part 307a or the second polymer part 307b in the directed self-assembly pattern 307 by, for instance, the oxygen plasma treatment. Then, the remaining first polymer part 307a or second polymer part 307b is used as a mask to process the first film 302. As a result, a line pattern is transcribed onto the first film 302.
In the present embodiment, the directed self-assembly material 306 is formed above the chemical guide (SOG film 303) having high surface flatness. Consequently, a microphase separating pattern may be easily transcribed onto the first film (lower film) 302.
In addition, in the present embodiment, pattern formation may be further simplified as compared to that described in the second embodiment because the formation/removal process of the neutralization film (refer to
Although the first to third embodiments explained the example where the resist is processed in a line-and-space pattern, and the directed self-assembly material layer is microphase separated in a lamellar form, the resist pattern form or directed self-assembly material may be changed, and the directed self-assembly material layer may also be microphase separated into a cylindrical form.
While certain embodiments have been described, these embodiments have been presented by way of example only, and they are not intended to limit the scope of the inventions. Indeed, the novel embodiments described herein may be embodied in a variety of other forms; furthermore, various omissions, substitutions and changes in the form of the embodiments described herein may be made without departing from the spirit of the inventions. The accompanying claims and their equivalents are intended to cover such forms or modifications as would fall within the scope and spirit of the inventions.
Claims
1. A pattern formation method, comprising:
- forming a first layer on a substrate;
- forming a second layer on the first layer;
- forming a resist pattern on the second layer in a line and space pattern, the space pattern having openings that expose a portion of the second layer;
- removing the resist pattern to form a first region and a second region on the second layer, wherein the first region has a greater hydrophobicity than the second region;
- forming a neutralization film on the second layer;
- removing the neutralization film;
- forming a directed self-assembly material layer containing a first segment and a second segment on the second layer after the neutralization film is removed;
- microphase separating the directed self-assembly material layer to form a self-assembled pattern containing a first polymer part that includes the first segment and a second polymer part that includes the second segment; and
- removing either the first polymer part or the second polymer part, using the other as a mask to process the first layer.
2. The method of claim 1, wherein removing the resist pattern comprises oxidizing the resist pattern.
3. The method of claim 2, wherein removing the resist pattern comprises exposing the resist pattern and the second layer to oxygen plasma.
4. The method of claim 2, wherein removing the resist pattern comprises exposing the resist pattern to ozonated water.
5. The method of claim 2, wherein removing the resist pattern comprises exposing the resist pattern to light in the vacuum-ultraviolet wavelength.
6. The method of claim 1, wherein removing the resist pattern comprises exposing the resist pattern to a solvent.
7. The method of claim 1, wherein the neutralization film alters the hydrophobicity of the first region.
8. The method of claim 7, wherein the neutralization film alters the hydrophobicity of the second region.
9. The method of claim 8, wherein the neutralization film increases the hydrophobicity of the second region.
10. A pattern formation method, comprising:
- forming a first film on a substrate;
- forming a second film on the first film;
- forming resist pattern on the second film, the resist pattern having a line-and-space pattern, wherein a line width is narrower than a space width;
- removing the resist pattern to form a first region and a second region on the second film, each of the first region and the second region having different hydrophobic properties;
- forming a neutralization film on the second layer;
- removing the neutralization film;
- forming a directed self-assembly material layer containing a first segment and a second segment on the line and space pattern after the neutralization film is removed;
- microphase separating the directed self-assembly material layer to form a pattern containing a first part that includes the first segment and a second part that includes the second segment; and
- removing either the first part or second part and using the other as a mask to process the first film.
11. The method of claim 10, wherein removing the resist pattern comprises oxidizing the resist pattern.
12. The method of claim 11, wherein removing the resist pattern comprises exposing the resist pattern to ozonated water.
13. The method of claim 11, wherein removing the resist pattern comprises exposing the resist pattern to light in the vacuum-ultraviolet wavelength.
14. The method of claim 11, wherein removing the resist pattern comprises exposing the resist pattern and the second layer to oxygen plasma.
15. The method of claim 14, wherein the first region corresponds to the space pattern and the second region corresponds to the line pattern, and after removal of the resist pattern, the area of the second region is reduced.
16. The method of claim 10, wherein the neutralization film alters the hydrophobicity of the first region.
17. The method of claim 16, wherein the neutralization film alters the hydrophobicity of the second region.
18. A pattern formation method, comprising: wherein:
- forming a base film on a substrate;
- forming a spin on glass film on the base film;
- forming a resist pattern having openings that expose a first region of the glass film;
- removing the resist pattern to form second regions adjacent the first region;
- forming a neutralization film on the second layer;
- removing the neutralization film;
- forming a directed self-assembly material layer on the glass film, the directed self assembly material layer containing a first segment and a second segment;
- microphase separating the directed self-assembly material layer to form a directed self-assembly pattern containing a first part that includes the first segment and a second part that includes the second segment; and
- removing either the first part or the second part and using the other as a mask to process the base film,
- the first region has a greater hydrophobicity than the second regions.
19. The method of claim 18, wherein the neutralization film alters the hydrophobicity of the first region.
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Type: Grant
Filed: Mar 4, 2013
Date of Patent: Apr 7, 2015
Patent Publication Number: 20140087566
Assignee: Kabushiki Kaisha Toshiba (Tokyo)
Inventors: Hirokazu Kato (Aichi), Ayako Kawanishi (Kanagawa)
Primary Examiner: Reema Patel
Application Number: 13/784,648
International Classification: H01L 21/302 (20060101); H01L 21/033 (20060101);