KR100904896B1 - Method of developing e-beam resist for patterning - Google Patents

Method of developing e-beam resist for patterning Download PDF

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KR100904896B1
KR100904896B1 KR1020080010047A KR20080010047A KR100904896B1 KR 100904896 B1 KR100904896 B1 KR 100904896B1 KR 1020080010047 A KR1020080010047 A KR 1020080010047A KR 20080010047 A KR20080010047 A KR 20080010047A KR 100904896 B1 KR100904896 B1 KR 100904896B1
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South Korea
Prior art keywords
electron beam
beam resist
developing
hsq
pattern
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KR1020080010047A
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Korean (ko)
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김기범
이효성
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재단법인서울대학교산학협력재단
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    • G—PHYSICS
    • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
    • G03F—PHOTOMECHANICAL PRODUCTION OF TEXTURED OR PATTERNED SURFACES, e.g. FOR PRINTING, FOR PROCESSING OF SEMICONDUCTOR DEVICES; MATERIALS THEREFOR; ORIGINALS THEREFOR; APPARATUS SPECIALLY ADAPTED THEREFOR
    • G03F7/00—Photomechanical, e.g. photolithographic, production of textured or patterned surfaces, e.g. printing surfaces; Materials therefor, e.g. comprising photoresists; Apparatus specially adapted therefor
    • G03F7/20—Exposure; Apparatus therefor
    • G03F7/2051—Exposure without an original mask, e.g. using a programmed deflection of a point source, by scanning, by drawing with a light beam, using an addressed light or corpuscular source
    • G03F7/2059—Exposure without an original mask, e.g. using a programmed deflection of a point source, by scanning, by drawing with a light beam, using an addressed light or corpuscular source using a scanning corpuscular radiation beam, e.g. an electron beam
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L21/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
    • H01L21/02—Manufacture or treatment of semiconductor devices or of parts thereof
    • H01L21/027—Making masks on semiconductor bodies for further photolithographic processing not provided for in group H01L21/18 or H01L21/34
    • H01L21/0271—Making masks on semiconductor bodies for further photolithographic processing not provided for in group H01L21/18 or H01L21/34 comprising organic layers
    • H01L21/0273—Making masks on semiconductor bodies for further photolithographic processing not provided for in group H01L21/18 or H01L21/34 comprising organic layers characterised by the treatment of photoresist layers
    • H01L21/0274—Photolithographic processes
    • H01L21/0275—Photolithographic processes using lasers

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  • General Physics & Mathematics (AREA)
  • Engineering & Computer Science (AREA)
  • Health & Medical Sciences (AREA)
  • Toxicology (AREA)
  • Optics & Photonics (AREA)
  • Condensed Matter Physics & Semiconductors (AREA)
  • Manufacturing & Machinery (AREA)
  • Computer Hardware Design (AREA)
  • Microelectronics & Electronic Packaging (AREA)
  • Power Engineering (AREA)
  • Photosensitive Polymer And Photoresist Processing (AREA)

Abstract

Disclosed is an electron beam resist developing method for pattern formation. In the method of developing an electron beam resist for forming a pattern according to the present invention, after preparing a substrate on which an electron beam resist is applied, the electron beam resist is irradiated to a portion to form a pattern of the substrate, and the electron beam is irradiated to a first developer, and then developed. In the first developing step, the impurities formed on the electron beam resist are etched and developed by exposing the etched substrate to the second developer. Developing the electron beam resist by the method according to the invention makes it possible to develop the electron beam resist supplied with a considerable amount of charge, thereby forming a high density pattern having a minimum wiring width of 10 nm or less.

Description

Method of developing E-beam resist for patterning

The present invention relates to a semiconductor manufacturing process, and more particularly, to a process of forming a pattern on a substrate.

In a semiconductor manufacturing process, a pattern on a substrate is generally formed through a lithography process. The lithography process is a process of forming a pattern on a substrate by etching the substrate using a resist pattern formed by applying a resist on the substrate and then exposing and developing the resist. Recently, as the degree of integration of devices increases, electron beam lithography processes have been studied to form nanoscale patterns. In this case, it has been reported that when the electron beam lithography process is performed using hydrogen silsesquioxane (HSQ) as an electron beam resist, a single line pattern having a size of 10 nm or less can be formed.

However, when the electron beam is irradiated to the HSQ electron beam resist, the electron beam is scattered, and the electron beam is also influenced in the region other than the region where the pattern is to be formed. The minimum wiring width is limited at 20 nm. This is because in the case of a high density pattern, the effects of electron beam scattering are superimposed so that more influence is made outside the region to form the pattern.

1 is a view showing the thickness of the HSQ electron beam resist remaining after the development according to the exposure dose of the electrons supplied to the HSQ electron beam resist when developing the HSQ electron beam resist exposed to the electron beam. As the developer, tetramethyl ammonium hydroxide (TMAH) was used.

Referring to FIG. 1, when more than 400 μC of charge per cm 2 is supplied to the HSQ electron beam resist, the HSQ electron beam resist remains unremoved even if developed for a long time. However, if a charge of about 100 μC per cm 2 is supplied to the HSQ electron beam resist, all HSQ electron beam resists are removed and the substrate is exposed even after 30 seconds development. And HSQ electron beam resist remaining after development according to the amount of electrons supplied to the HSQ electron beam resist when the development time is maintained for 1 minute (-▲-), 3 minutes (-*-) and 5 minutes (-◆-). It can be seen that the thickness of is almost constant. This means that if a certain amount of charge is supplied to the HSQ electron beam resist, the HSQ electron beam resist remains unremoved even after long development.

Therefore, the area to form a pattern is irradiated with an electron beam so that a charge of 400 μC or more per 1 cm 2 is supplied to the HSQ electron beam resist, and the area where a pattern is not formed is irradiated with an electron beam so that a charge of 100 μC or less per 1 cm 2 is supplied to an HSQ electron beam resist. It is desirable to investigate.

However, as described above, in the high-density pattern, the scattering effect of the electron beam is increased, so the area to form the pattern is irradiated with the electron beam so that a charge of 400 μC or more per 1 cm 2 is supplied to the HSQ electron beam resist, and the area not to form the pattern is 1 cm 2. It is not easy to irradiate the electron beam so that a charge of 100 μC or less is supplied to the HSQ electron beam resist. That is, unlike a single line pattern, when forming a high-density pattern, scattering of the electron beams overlaps, and thus it is difficult to form a pattern having a size of 20 nm or less. Therefore, even if a charge of 100 μC or more per 1 cm 2 is supplied to the HSQ electron beam resist, development is needed to develop the substrate to expose the HSQ electron beam resist.

The technical problem to be solved by the present invention is to provide a method that can easily develop the electron beam resist formed in the region not to form a pattern.

In order to solve the above technical problem, an electron beam resist development method for forming a pattern according to the present invention comprises the steps of preparing a substrate coated with an electron beam resist; Irradiating an electron beam on a portion of the substrate to form a pattern; A first developing step of developing by exposing the substrate irradiated with the electron beam to a first developer; An etching step of etching the impurities formed on the electron beam resist in the first developing step; And a second developing step of developing the etched substrate by exposure to a second developer.

According to the electron beam resist development method for pattern formation according to the present invention, since the impurities generated while developing the electron beam resist are etched and then developed again, all of the electron beam resists formed in the region where the pattern is not to be formed can be easily developed. Further, when the electron beam resist is developed by the method according to the present invention, it is possible to develop the electron beam resist supplied with a considerable amount of charge, thereby forming a high density pattern having a minimum wiring width of 10 nm or less.

Hereinafter, with reference to the accompanying drawings will be described in detail a preferred embodiment of the electron beam resist development method for pattern formation according to the present invention. However, the present invention is not limited to the embodiments disclosed below, but will be implemented in various forms, and only the present embodiments are intended to complete the disclosure of the present invention and to those skilled in the art to fully understand the scope of the invention. It is provided to inform you.

2 is a flowchart illustrating a process of performing a preferred embodiment of the electron beam resist development method for pattern formation according to the present invention.

Referring to FIG. 2, first, a substrate on which an electron beam resist is applied is prepared (S210). The substrate is a silicon wafer, the electron beam resist is a negative type resist, preferably a hydrogen silsesquioxane (HSQ) is used. The HSQ electron beam resist is applied onto the substrate by spin coating.

Next, the electron beam is irradiated to a region to form a pattern on the substrate (S220). Since a negative electron beam resist is used, an electron beam is irradiated to the area to form a pattern on a substrate. In this embodiment, the electron beam has a radius of 50 nm.

The first developing step of developing the electron beam resist is performed by exposing the substrate irradiated with the electron beam to the first developer (S230). As the first developer, any one of tetramethyl ammonium hydroxide (TMAH) and KOH may be used. In this embodiment, the 25wt% TMAH aqueous solution was used as the first developer and developed at 21 ° C. The substrate exposed to the first developer is washed with DI (deionized) water and then dried with nitrogen (N 2 ). When the first development step is performed, as shown in FIG. 1, all of the HSQ electron beam resists in the region supplied with the charge of 100 μC or less per 1 cm 2 are removed, but when the predetermined amount of charge is supplied, all the HSQ electron beam resists are not removed. Can be.

Even if the development time lasts for a long time, none of the HSQ electron beam resists are removed, because impurities such as siloxane are formed on the HSQ electron beam resists and interfere with the development of the HSQ electron beam resists. In order to analyze such a phenomenon, XPS (X-ray photoelectron spectra) analysis was performed, and the Si 2p spectra of the XPS analysis results are shown in FIGS. 3 (a) to 3 (c).

FIG. 3 (a) shows the XPS results obtained by applying only the HSQ electron beam resist on the substrate, and FIG. 3 (b) shows the XPS results after irradiating the HSQ electron beam resist with an electron beam corresponding to 280 μC / cm 2 . 3 (c) shows the result of XPS after performing the first development step with a 25 wt% TMAH aqueous solution at 21 ° C. FIG. Figure 3 (a) to Fig. 3 (c) to the left of the Gaussian (Gaussian) distribution shown in each figure (320, 340, 360) is in that the Si 4 + peak (peak), and right (310, 330, 350) corresponds to the Si 3 + peak. Si 3 + peak in this embodiment means a state in which silicon (Si) contained in the electron beam resist HSQ is a bond and the hydrogen (H) and, Si 4+ peaks of silicon contained in the electron beam resist all HSQ It means that the bond with hydrogen is broken and combined with oxygen.

Referring to FIG. 3 (a), the HSQ electron beam resist applied on the substrate shows that the Si 4 + peak 320 hardly appears and only the Si 3 + peak 310 appears large, so that most silicon is combined with one hydrogen. It is in a state. By following the HSQ the electron beam resist is looking for a (S220) 3 after (b) irradiation in the electron beam Si 4 + peak 340 is increased as viewed some silicon is supplied to the electron beam break the bonds with the hydrogen bond and oxygen It can be seen that.

Referring to FIG. 3 (c) which is an XPS result after the first developing step S230, it can be seen that the Si 4 + peak 360 suddenly increases and the Si 3 + peak 350 decreases. This means that a large amount of silicon on the surface of the HSQ electron beam resist breaks down with hydrogen and combines with oxygen during development to form siloxane on the surface of the HSQ electron beam resist. And siloxane is not removed by the developer.

As a result, the siloxane on the surface must first be etched to remove all of the HSQ electron beam resist. Therefore, next, the impurities formed on the electron beam resist are etched (S240). At this time, the etching solution for etching is a solution containing hydrofluoric acid (HF). The siloxane is easily etched by a solution containing hydrofluoric acid. In this embodiment, the solution used for etching was diluted 1: 4000 in hydrofluoric acid and water, and the etching rate in the case of etching using such an etching solution is 2 nm per minute. Since siloxane is formed only on the surface, and hydrofluoric acid is etched on both the irradiated portion and the non-irradiated portion, only one minute is etched so that only the surface of the HSQ electron beam resist can be etched.

The XPS result after etching with the above-described etching solution (S240) is shown in Fig. 3 (d). Referring to FIG. 3 (d), it can be seen that the Si 3 + peak 370 increases and the Si 4 + peak 380 decreases to form a shape similar to that of FIG. 3 (b). This is because the siloxane formed on the surface was etched to expose the internal HSQ electron beam resist to the surface.

Next, a second developing step of developing the electron beam resist using the second developing solution is performed (S250). Since all the siloxanes which hindered the development were etched, the substrate was exposed to the developer again to remove the HSQ electron beam resist in the portion where the electron beam was not irradiated. The second developer may be the same as the first developer, and any one of TMAH and KOH may be used.

4 shows the remaining HSQ electron beam after development according to the amount of electrons supplied to the HSQ electron beam resist in the case where only the first development step and the first development step, the etching step and the second development step are performed. It is a figure which shows the thickness of a resist. FIG. 5 is a diagram illustrating a development rate according to the amount of electrons supplied to the HSQ electron beam resist when only the first developing step is performed and when the first developing step, the etching step and the second developing step are performed. . All developing time of FIG. 4 and FIG. 5 was made into 1 minute.

Referring to FIG. 4, when only the first developing step is performed (-■-, 410), as shown in FIG. 1, only the HSQ electron beam resist having a predetermined thickness is developed and no longer developed. In addition, when the etching is performed after the first developing step (-●-, 420), it can be seen that the HSQ electron beam resist of about 2 nm is further removed. This is because etching was performed for 1 minute using an etching solution having an etching rate of 2 nm / min as described above. In the case where the second development step is performed after the etching is performed (-Δ-, 430), the development proceeds again, and the development is performed again to the extent developed in the first development step, indicating that the HSQ electron beam resist is removed.

Referring to FIG. 5, it can be seen that the developing speeds of the first developing step and the second developing step are the same regardless of the amount of electrons supplied to the HSQ electron beam resist. This means that the first developing step and the second developing step are caused by the same mechanism. That is, the HSQ electron beam resist after etching exhibits the same characteristics as the HSQ electron beam resist before performing the first developing step.

6A to 7B show the results of forming the patterned HSQ electron beam resist by performing only the first development step and all of the first development step, the etching step and the second development step.

FIG. 6 (a) is a plan-view scanning electron microscope (SEM) image showing a line pattern when the HSQ electron beam resist irradiated with an electron beam of 400 mu C / cm 2 is performed only in the first developing step, and FIG. b) is a planar SEM image showing the line pattern when the HSQ electron beam resist irradiated with the 400 μC / cm 2 electron beam according to the present invention is subjected to the first developing step, the etching step and the second developing step. FIG. 7 (a) is a planar SEM image showing a dot pattern when the HSQ electron beam resist irradiated with 37 fC electron beam at each dot is performed only in the first developing step, and FIG. Accordingly, it is a planar SEM image showing a dot pattern when the HSQ electron beam resist irradiated with 37 fC electron beam to each point is subjected to the first development step, etching step and second development step.

6A and 6B, when only the first development step is performed (FIG. 6A), the substrate indicated by reference numeral 610a is not exposed as much as desired. This is because neither of the HSQ electron beam resists 610b has been developed. In contrast, in the case where all of the first developing step, the etching step and the second developing step are performed (FIG. 6 (b)), the substrate indicated by reference numeral 610b is exposed to a desired degree. This is because the HSQ electron beam resist 620b at the position where the pattern is not formed is removed through etching and the second development step.

Referring to FIGS. 7A and 7B, when only the first developing step is performed (FIG. 7A), the substrate 710a is not exposed to a desired level, so that the dot pattern 720a is perfectly formed. It can be seen that it remains unconnected by the undeveloped HSQ electron beam resist 730. In contrast, in the case where all of the first developing step, the etching step, and the second developing step are performed (FIG. 7B), all the dot patterns 720b are perfectly formed in an island shape, and the dot pattern ( It can be seen that the substrate 710a around 720b is completely exposed without being obscured by the HSQ electron beam resist.

As a result, when the HSQ electron beam resist is developed through the first development step, the etching step, and the second development step as described above, more HSQ electron beam registers remaining in unwanted areas can be removed, thereby forming a pattern of a desired shape. You can do it.

2, it is checked whether the substrate is exposed to the region where the pattern is not to be formed (S260). As shown in FIG. 4, even when the development is performed up to the second development step, if the amount of electrons supplied to the HSQ electron beam resist is large, all of the HSQ electron beam resist may not be removed. Therefore, if all of the HSQ electron beam resists have not been removed, the process of etching again to remove the siloxane formed on the surface of the HSQ electron beam resist and then developing again should be repeated until all of the HSQ electron beam resists are removed. In other words, if the substrate is not exposed in the region where the pattern is not to be formed, steps S240 and S250 are performed again to expose the substrate.

Although the preferred embodiments of the present invention have been shown and described above, the present invention is not limited to the specific preferred embodiments described above, and the present invention belongs to the present invention without departing from the gist of the present invention as claimed in the claims. Various modifications can be made by those skilled in the art, and such changes are within the scope of the claims.

1 is a view showing the thickness of the HSQ electron beam resist remaining after development according to the amount of electrons supplied to the HSQ electron beam resist when developing the HSQ electron beam resist exposed to the electron beam.

2 is a flowchart illustrating a process of performing a preferred embodiment of the electron beam resist developing method for pattern formation according to the present invention.

3 (a) is a diagram showing XPS results in a state in which only HSQ electron beam resist is applied onto a substrate.

3 (b) is a diagram showing XPS results after irradiating an HSQ electron beam resist with an electron beam corresponding to 280 μC / cm 2 .

Figure 3 (c) is a view showing the XPS results after performing the first development step in a 25wt% TMAH aqueous solution at 21 ℃.

Figure 3 (d) is a view showing the XPS results after performing etching for 1 minute with hydrofluoric acid.

4 shows the thickness of the HSQ electron beam resist remaining after development according to the amount of electrons supplied to the HSQ electron beam resist when only the first development step is performed and when the first development step, the etching step and the second development step are performed. The figure shown.

FIG. 5 is a diagram illustrating a developing speed according to the amount of electrons supplied to the HSQ electron beam resist when only the first developing step is performed and when the first developing step, the etching step and the second developing step are performed.

6 (a) is a plan-view scanning electron microscope (SEM) image showing a line pattern when the HSQ electron beam resist irradiated with an electron beam of 400 μC / cm 2 is performed only in the first developing step.

FIG. 6 (b) is a planar SEM image showing a line pattern when the HSQ electron beam resist irradiated with 400 μC / cm 2 electron beam is subjected to the first development step, etching step and second development step according to the present invention.

FIG. 7A is a planar SEM image showing a dot pattern when the HSQ electron beam resist irradiated with 37 fC electron beam to each dot is performed only in the first developing step.

FIG. 7B is a planar SEM image showing a dot pattern when the HSQ electron beam resist irradiated with 37 fC electron beams on each point is subjected to the first developing step, the etching step and the second developing step.

Claims (5)

Preparing a substrate coated with an electron beam resist; Irradiating an electron beam on a portion of the substrate to form a pattern; A first developing step of developing by exposing the substrate irradiated with the electron beam to a first developer; An etching step of etching the impurities formed on the electron beam resist in the first developing step; And And a second developing step of developing the etched substrate by exposure to a second developing solution. The method of claim 1, And sequentially performing the etching step and the second developing step at least once after the second developing step. The method according to claim 1 or 2, The electron beam resist is an electron beam resist development method for pattern formation, characterized in that the hydrogen silsesquioxane (HSQ). The method according to claim 1 or 2, The first developer and the second developer is the same as any one of TMAH (tetramethyl ammonium hydroxide) and KOH, the electron beam resist development method for pattern formation. The method according to claim 1 or 2, The etching step is an electron beam resist development method for pattern formation, characterized in that for etching the impurity using a solution containing HF.
KR1020080010047A 2008-01-31 2008-01-31 Method of developing e-beam resist for patterning KR100904896B1 (en)

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Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5328560A (en) 1992-06-09 1994-07-12 Mitsubishi Denki Kabushiki Kaisha Method of manufacturing semiconductor device
KR19980077751A (en) * 1997-04-22 1998-11-16 윤종용 Photoresist Pattern Formation Method
JP2002270487A (en) 2001-03-09 2002-09-20 Matsushita Electric Ind Co Ltd Method of forming resist pattern and method of manufacturing semiconductor device using the method
KR20040056116A (en) * 2002-12-23 2004-06-30 주식회사 하이닉스반도체 Method of manufacturing a semiconductor device

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5328560A (en) 1992-06-09 1994-07-12 Mitsubishi Denki Kabushiki Kaisha Method of manufacturing semiconductor device
KR19980077751A (en) * 1997-04-22 1998-11-16 윤종용 Photoresist Pattern Formation Method
JP2002270487A (en) 2001-03-09 2002-09-20 Matsushita Electric Ind Co Ltd Method of forming resist pattern and method of manufacturing semiconductor device using the method
KR20040056116A (en) * 2002-12-23 2004-06-30 주식회사 하이닉스반도체 Method of manufacturing a semiconductor device

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