KR960015482B1 - Lithographic developer and lithographic process - Google Patents

Abstract

No content

Description

Lithography Developer and Lithography Process

1 is a graph showing mask fidelity of a resist pattern developed with the developer of the present invention;

2 is a schematic diagram showing the transfer mask used in the design of the contact hole,

3 is a graph showing surfactant concentration dependency of exposure threshold energy of contact hole formation in Example 1;

4 is a photograph showing profiles of 0.8 μm, 0.7 μm, and 0.6 μm contact holes formed using a g line reduction projection exposure apparatus having a NA value of 0.43 and a developer of the present invention;

5 is a photograph showing a profile of 0.6 µm, 0.5 µm and 0.4 µm contact holes formed using a g line reduction projection exposure apparatus having an NA value of 0.55 and a developer of the present invention;

6 is a conceptual diagram showing a manufacturing method of ultrapure ozone-containing water,

7A and 7B are XPS spectra showing that the surfactant is removed from the silicon surface by washing with ultrapure water containing ozone,

8 is a graph showing that the surfactant is removed from the silicon surface by washing with ultrapure water containing ozone according to the contact angle measurement,

9A and 9B are photographs showing a 0.6 μm line-and-space pattern after washing with ultrapure ozone-containing water,

9A; Before cleaning.

9B; After cleaning.

10A and 10B are photographs showing the roughness of the silicon surface when the developer of the present invention or the conventional developer is used;

Figure 10A; Conventional developer.

10B; Developer of the present invention.

11 is a graph showing the relationship between the molecular weight of the surfactant used in the present invention, the ratio of the hydrophilic group [(A + B) / (A + B + C)], foamability and cloud point,

12 is a graph showing the relationship between resist film thickness and developer immersion time;

13 is a graph showing the relationship between the exposure threshold energy required for contact hole formation and the concentration of the surfactant in the developer;

14A and 14B are electron micrographs showing the effect of the surfactant in the developer on the shape of the hole when forming contact holes of different sizes,

14A; Resist MCPRi 6600.

14B; Resist THMRip 1800.

15A and 15B are electron micrographs showing 0.35 占 퐉 contact holes formed by using a developer and exposed by varying the focus positions.

Figure 15A; Resist MCPRi 6600.

Figure 15B; Resist THMRip 1800.

16 is a graph showing the TMAH concentration dependence of the selectivity of the resist to the developer;

Figure 17 is a photograph showing a 0.55㎛ line and space pattern formed by a conventional developer,

18 is a graph showing the change of the centerline average roughness of the silicon surface by immersion in the developer;

19 is a graph showing the deterioration of the channel mobility of the MOSFET by the developer;

20 is an XPS spectrum showing adsorption of surfactant to silicon wafer surface,

21A and 21B are photographs showing a profile of a contact hole formed using a conventional developer;

22 is a graph showing the dependence of the exposure threshold energy on the concentration of the surfactant added to the developer to form a contact hole using a conventional developer;

FIG. 23 is a photograph showing a contact hole formed using a developer containing a surfactant as shown in FIG.

The present invention relates to a developer (developer) for lithography and a lithography process, and more particularly, to a lithography developer and a lithography process suitable for an ultra high density integration process.

In recent years, with the increase in density and size of semiconductor devices, the lithography process requires the formation of fine resist patterns with process margins. For this reason, photoresists having a high resolution are used for pattern formation, and these resists are positive or negative, usually 2.38 of an alkaline developer, for example, tetramethylammonium hydroxide (hereinafter referred to as TMAH). Pattern formation is performed by the weight% aqueous solution.

As the resist material is made to have high resolution, the ratio of the dissolution rate of the exposed portion and the non-exposed portion of the resist layer, that is, the selectivity of the resist to the developer, is improved, and the state is shown in FIG. In FIG. 16, the ratio of the dissolution rate of the exposed portion to the non-exposed portion of the resist layer is shown as a function of TMAH concentration. In the figure, the resolution of the labeled photoresist A is 1.2 mu m and the positive photoresist B is shown. Is 0.8 µm and the positive photoresist C is 0.6 µm. As shown in the figure, it can be seen that the selectivity of the resist increases exponentially as the resolution of the resist improves. In other words, it can be seen that realizing a high resolution resist is the same as improving the selectivity of the exposed portion and the non-exposed portion of the resist layer.

In order to improve the developing ability, there have been attempts to increase the concentration of the developing solution, but in this case, the selectivity of the exposed portion and the non-exposed portion of the resist layer is lowered, resulting in deterioration of the resolution performance of the resist.

FIG. 17 shows a 0.55 μm line-and-space resist pattern developed by a developer without adding a surfactant of the conventional form. The exposure was performed using a g-line reduction projection exposure apparatus with a lens having a numerical aperture of 0.43. Since the wettability on the resist surface of the developer is poor, trailing of the resist pattern after development and the occurrence of residues (circles in FIG. 17) can be seen. In order to suppress this phenomenon, in some cases, a developer containing a surfactant is used. However, when some types of substrates are used, a developer containing a surfactant so far can suppress the generation of a resist residue. On the contrary, the addition of this type of surfactant lowered the sensitivity of the resist or the exposure margin.

FIG. 18 shows the flatness of the surface after immersing a silicon wafer for 60 seconds in a developer without adding a conventional surfactant, using a centerline average roughness. As can be seen from this, compared to the reference wafer which is not immersed in the developer, the wafer immersed in the developer is only in contact with the developer for a short time of 60 seconds and the surface becomes very rough. In addition, when a semiconductor device is manufactured in such a surface state, its electrical characteristics are significantly degraded.

Fig. 19 shows data obtained by fabricating a MOS transistor using such a rough surface wafer and examining channel mobility. It can be seen that the channel mobility is extremely deteriorated with respect to the reference value when the surface is roughened in contact with the developer.

In addition, when a specific surfactant is added to the developer, silicon surface roughness is prevented, but the surfactant is adsorbed on the silicon. In FIG. 20, data obtained by observing 15 peaks of carbon by X-ray photoelectron spectroscopy (XPS) are shown. The data from the silicon surface exposed to the developer containing the surfactant for 60 seconds shows the peak 1501 indicating the presence of the surfactant. It was found that when a developer containing a surfactant was used, the surfactant was adsorbed onto the lower substrate and was not removed by a normal washing process. If the surfactant is adsorbed on the surface of the substrate, it becomes a carbon contamination, resulting in a decrease in film quality in the subsequent formation of various thin films. On the other hand, if a surfactant that does not adsorb on the silicon surface is selected, the silicon surface becomes rough.

Under these circumstances, if a contact hole was formed using a resist having a resolution of up to 0.6 µm (which can form a line-and-space pattern with mask fidelity), the resist could not exert its capability. .

21 shows a cross-sectional photograph of a contact hole developed using a conventional developer. Under exposure conditions (220 mJ / cm 2) in which a contact hole of 0.8 μm size is formed, 0.7 μm and 0.6 μm holes are underexposure conditions.

Under exposure conditions (280 mJ / cm 2) in which a contact hole of 0.7 μm size is formed, the 0.8 μm hole is an overexposure condition, and the 0.6 μm hole is an underexposure condition. In other words, in a region (e.g., a hollow region) where their own exposure area is small, the wettability of the developing solution is poor and does not penetrate the resist pattern, so that the resist performance cannot be sufficiently exhibited.

In order to improve the wettability of the developer, a developer containing a surfactant is used. 22 shows the relationship between the concentration of the surfactant added to the developer and the exposure threshold energy for contact hole formation. Contact hole exposure threshold energy refers to the exposure energy required for the bottom of the contact hole to reach the lower substrate. Increasing the concentration of the surfactant added to the developer lowers the exposure threshold energy, but the difference in the exposure threshold energy between different hole sizes does not change from the state before the surfactant addition. That is, using the surfactants up to now, it was impossible to form microcontact holes having different sizes with high accuracy under the same exposure conditions.

FIG. 23 shows a cross-sectional photograph of a contact hole formed by using a developer containing a surfactant as shown in FIG. FIG. 23 shows that the side wall of the contact hole becomes curved when the conventional surfactant is added, and in order to improve the wettability of the developing solution, increasing the amount of the surfactant added so far causes deterioration of the hole shape. Occurred.

SUMMARY OF THE INVENTION The present invention has been made in view of the above point, and an object of the present invention is to provide a developer for lithography and a lithography process capable of developing a fine resist pattern having all regions of different sizes and shapes as the original design. .

In the lithography developer of the present invention, in the lithography developer used to develop a resist pattern having regions of different sizes and shapes by dissolving and removing the resist region of the resist layer formed on the resist pattern, the developer is the resist. It is characterized by containing a surfactant which can increase the dissolution of the resist of the resist area to be dissolved by small dissolution removal area on the surface of the layer.

In the lithography process of the present invention, in the lithography process of dissolving and removing a resist region of a resist layer formed on a resist pattern in order to develop a resist pattern having regions of different sizes and shapes, A lithography developer containing a surfactant capable of increasing the dissolution of the resist in the resist region to be dissolved and removed with a small dissolution removal area on the surface is used for at least part of the resist pattern development.

In the present invention, a developer containing a surfactant capable of increasing dissolution of the resist in a smaller resist region is used. Therefore, when a resist pattern formed by projecting a pattern having regions of different sizes using a pattern forming apparatus is developed using this developer, the surfactant is adsorbed on the resist surface. Next, since the surfactant is usually present in the microregions where the liquid does not easily penetrate, the development proceeds through the same process as the resist region having a relatively large pattern region. For this reason, regardless of the size and development of the resist area, a fine resist pattern having a different size and development area can be developed as originally designed, and moreover. It is possible to realize an ultra-high density and ultra-high speed LSI.

The surfactant used in the lithography developer and the lithography process is preferably a surfactant having antifoaming properties.

As the surfactant, for example, an amine surfactant having a ethylene-propylene block as a branched chain group, a hydrophilic group, and the like having a amine group, an ethylene oxide group and / or a propylene oxide, and the like are preferable. It is preferable that the density | concentration of these surfactant shall be 300 ppm or more.

The surfactant used in the present invention is the following general formula (I)

HO (CH ₂ CH ₂ O) _a (CH (CH ₃ ) CH ₂ O) _b (CH ₂ CH ₂ O) _c ) H (I)

Especially preferable are surfactants represented by (a, b, c are integers).

Furthermore, when the molecular weight of HO (CH ₂ CH ₂ O) a is A, the molecular weight of (CH (CH ₃ ) CH ₂ O) _b is B, and the molecular weight of (CH ₂ CH ₂ O) _c H is C, A , Between B and C

(A + C) / (A + B + C) ≤0.2

Is particularly preferred, and the molecular weight of the surfactant is preferably 4,000 or less. The concentration of the surfactant in the developer is preferably 100 ppm to 1,000 ppm.

As surfactant used for this invention, surfactant represented by Formula (I) is preferable, and foaming at the time of image development can be suppressed further by optimizing the structure and molecular weight of surfactant, and also the film loss of a non-exposed part. This can be further suppressed to form a fine pattern with very high accuracy.

11 shows the relationship between the molecular weight of the surfactant and the ratio [(A + C) / (A + B + C)] of the hydrophilic group to foamability and cloud point. As is apparent from FIG. 11, by decreasing the proportion of the hydrophilic group, the foamability is reduced, and the generation of bubbles at 30% is not seen at all, and there is no pattern defect caused by the bubbles. Moreover, when the molecular weight of surfactant is 4000 or less, cloud point can be 25 or more, and under normal developing conditions, there is no precipitation influence of surfactant, and a pattern can be formed with high precision.

In the lithography step, the resist exposure may be performed using a g line or i line reduction projection exposure apparatus.

In addition, it is preferable to remove the surfactant adsorbed on the resist surface or the lower substrate of the resist with ultrapure water containing ozone of 0.1 ppm or more, and in this case, the concentration of ozone in the ultrapure water is preferably 2.0 ppm or more. .

In particular, the effect of the present invention is more remarkable when the size of the resist pattern is 0.5 µm or less.

Further, when the amount of the surfactant added is 100 ppm or more, the wettability is further improved, and it is easier to form a random pattern in which other resist regions are mixed. Moreover, the upper limit of addition amount is 1,000 ppm from the solubility of surfactant.

(Example 1)

A first embodiment of the present invention will be described with reference to the drawings. FIG. 1 shows the design fidelity of the line-and-space pattern of the resist exposed by the g-line reduction projection exposure apparatus having a numerical aperture of 0.43 and developed with the developer (TMAH content; 2.38 wt%) of the present embodiment. The positive resist (TSMR-V50; manufactured by Tokyo Kakogyo Co., Ltd.) has a resolution of 0.6 µm, but in the developing step using the developer of the present invention, the type of resist is not particularly problematic.

The surfactant used in this embodiment is an amine antifoaming surfactant having a branched chain of ethylene-propylene block, or a lithography developer containing a surfactant that can increase the dissolution of a resist in a smaller resist area. You just need That is, in developing a resist pattern having regions of different sizes and shapes, with respect to the resist region to be dissolved and removed from the resist layer formed on the resist pattern, the resist region to be dissolved and removed with a small dissolution removal area on the surface of the resist layer What is necessary is just a surfactant which can increase the dissolution of a resist.

The phenomenon of the contact hole after the developing process using these resists and a developing solution was observed with the scanning microscope.

2 shows the transfer mask used for the design of the contact hole. One fifth of the size on the mask 201 becomes the actual size. On the 5-inch-diameter n-type (100) silicon substrate, a positive resist layer (resist: TSMR-V50; manufactured by Tokyo Okaka Co., Ltd.) having a film thickness of 1.26 mu m is formed. By a g-line reduced projection exposure apparatus having a lens having a numerical aperture of 0.43, the test pattern 202 is subjected to five-to-one reduction projection on the sample surface through the mask 201. Regarding the difference between the types of the resist pattern forming apparatus, since there is no influence in the present invention, other apparatuses may be used.

Thereafter, the sample is immersed in the developing solution of the present embodiment for 70 seconds, washed with ultrapure water for 60 seconds to form a hole. The spacing between the holes is twice the size of the hole. For example, in the case of a 0.6 μm size hole, the distance is 1.2 μm. In this embodiment, first, a hole having a size of 0.6 µm to 0.6 µm is manufactured.

3 shows the concentration dependency of the exposure threshold energy for the formation of the contact hole, and as the surfactant increases, the decrease in the exposure threshold energy is observed in the small size of the hole.

That is, in the case of a 0.8 μm hole, the concentration dependence of the surfactant of the exposure threshold energy is not very low. However, as the hole size decreases to 0.7 μm and 0.6 μm, the exposure threshold energy decreases remarkably with increasing the concentration of the surfactant. . When the addition concentration of the surfactant was 300 ppm or more, contact holes up to 0.6 µm could be formed under the same exposure conditions. This phenomenon is due to the use of the developer of the present embodiment, and has a capability of increasing the dissolution of the resist in a smaller size resist area.

Next, the cross section of the hole was observed with a scanning electron microscope. 4 shows profiles of contact holes of 0.8 μm, 0.7 μm, and 0.6 μm. When the conventional developer is used, the recess side wall is curved, but in the case of the developer used in this example, the recess side wall was sharp. This phenomenon is characterized by the fact that the developer selectively penetrates into the fine region, the dissolution reaction product diffuses rapidly and is removed from the resist surface, and the smaller the resist region is, the more rapidly the fresh developer is supplied. This is because the phenomenon progresses through the same process.

Subsequently, a contact hole up to 0.4 [mu] m was formed using a g-line reduced projection exposure apparatus having a lens having a numerical aperture of 0.55 manufactured to form a high resolution pattern.

5 shows a cross-sectional photograph of a contact hole of 0.8 μm, 0.5 μm, and 0.4 μm. The exposure energy was 280 mJ / cm 2, and exposure was performed under the same exposure conditions.

As apparent from Fig. 5, by using the developer of the present embodiment, it was possible to form a favorable hole accurately under the same exposure conditions, up to a 0.4 µm hole, which could not be formed conventionally. This phenomenon is achieved by a developer having an effect of increasing the developing ability as the ultrafine pattern that is difficult to develop.

From the above results, it was confirmed that with the developer of this embodiment, regardless of the size and shape of the resist region, in particular, a microresist pattern of 0.5 µm or less could be developed as originally designed by the g-line reduction projection exposure apparatus.

(Example 2)

A second embodiment of the present invention will be described with reference to FIGS. 6 to 10B.

FIG. 6 is a conceptual diagram showing a method for producing ozone-containing ultrapure water used for washing ozone-containing ultrapure water of this embodiment. In the apparatus shown in FIG. 6, ozone is generated by electrolysis of ultrapure water and dissolved in ultrapure water supplied separately. As an ozone generator (ozonizer), a commercially available product can be used, and no special treatment is necessary.

By using this apparatus, it is possible to supply ozone concentration in ultrapure water up to 0.01 to 10 ppm with high accuracy and stability.

FIG. 7 shows an X-ray photoelectron of 15 peaks of carbon obtained from a sample obtained by immersing a silicon wafer for 60 seconds in a developing solution used in the present invention, followed by washing with water for 60 seconds, and a sample with 60 ppm of ultrapure water containing 2 ppm of ozone. Data analyzed by spectroscopy. In water washing with ultrapure water, the surfactant peak 701 is seen on the silicon surface, whereas in water washing with ultrapure water containing 2 ppm of ozone, the surfactant peak 701 is not seen. It was confirmed that the surfactant adsorbed on the silicon surface was decomposed and removed by washing with ultrapure water containing ozone at room temperature. It was also confirmed that the same effect was obtained by setting the washing time to 10 minutes even when the ozone addition concentration to ultrapure water was 0.1 ppm.

Next, the sample in which the non-exposed positive resist thin film was formed was immersed in the developing solution containing surfactant of this invention for 60 second, and surfactant was made to adsorb | suck on the surface. Thereafter, the treatment was performed with ultrapure water containing 2 ppm of ozone to investigate the contact angle of the ultrapure water on the sample surface.

8 shows the relationship between the ozone-containing ultrapure water cleaning time and the ability of the surfactant to be removed from the resist surface. Since the surfactant is adsorbed on the resist surface before washing with ultrapure water containing 2 ppm of ozone, the contact angle is lower than that of the clean resist surface. However, after 60 seconds or more of cleaning, it was confirmed that the surfactant could be removed in perfect agreement with the value of the contact angle on the surface of the clean resist.

9 shows a profile of a 0.6 탆 resist pattern before and after cleaning with ultrapure water containing 2 ppm of ozone. No difference was observed in the profile of the resist pattern of 0.6 µm before and after washing with ultrapure water containing 2 ppm of ozone, and it was confirmed that there was no adverse effect such as deformation of the resist pattern due to ozone.

FIG. 10 shows the surface photograph after immersing a silicon wafer in a developer used in the present invention and a conventional developer for 30 minutes, followed by washing with ultrapure water containing 2 ppm of ozone.

It was confirmed that surface roughness of silicon occurs when immersed in a developer that does not contain a conventional surfactant, but surface roughness of silicon does not occur in the developer used in the present invention.

(Example 3)

In this embodiment, as a developing solution, NMD-3 (TMAH content 2.38 wt%, manufactured by Tokyo Kakokyo Co., Ltd.), a surfactant (EPAN610, manufactured by Daiichi Kogyo Seiyaku Co., Ltd.), (A + C ) / (A + B + C) = 0.1 and molecular weight 1,944) were used at various concentrations. As the resist, MCPRi 6600 and THMRip 1800 (manufactured by Mitsubishi Kasei Co., Ltd.) were used.

In the same manner as in Example 1, after forming a resist layer of 1.085 mu m on an n-type (100) silicon substrate having a diameter of 5 inches, the mask 201 was formed by a g-ray reduction projection exposure apparatus having a lens having a numerical aperture of 0.55. ), The test pattern 202 was subjected to a 5: 1 reduction projection on the sample surface. Next, the samples were immersed in various developing solutions for various times.

As a comparison, the same experiment is conducted using a developer NMD-3 containing no surfactant and a developer containing a conventional surfactant.

FIG. 12 shows the relationship between the development time and the resist film loss. As shown in the figure, when the developer containing the conventional surfactant is used, the film loss is remarkable. As in the case of the developer not containing, there was almost no film loss after 10 minutes, and it was found that no problem occurred when developing for a normal developing time (about 1 minute). FIG. 12 shows the case where MCPRi 6600 is used as the resist, but it was also confirmed that there was almost no film loss even when THMRip 1800 was used.

Next, as a result of examining the relationship between the exposure threshold energy required to form contact holes of various sizes and the concentration of the surfactant, the difference in the exposure threshold energy corresponding to each contact hole decreases with the increase in the amount of the surfactant added. As shown in FIG. 13, it was found that the exposure threshold energy was kept constant within the range of 100 to 1000 ppm.

The results of observing the contact hole of the sample obtained by immersing the exposed sample for 70 seconds in the developing solution and the developing solution containing no surfactant for 70 seconds and then washing with ultrapure water for 60 seconds are shown in FIGS. 14A and 14B. It is shown in Figure 14B.

As is apparent from FIGS. 14A and 14B, by using the developer of the present embodiment, a pattern in which 0.3 µm to 1.0 µm holes, which could not be conventionally formed for both MCPRi 6600 and THMRip 1800, was mixed, can be accurately formed under the same exposure conditions. there was.

In this example, EPAN610 was used as the surfactant, but the same was true even when EPAN 420 (molecular weight 1,200, hydrophilic group 20%) and EPAN720 (molecular weight, 2,000, hydrophilic group 20%) having different molecular weights and hydrophilic group ratios were used. Get the result.

(Example 4)

In the same manner as in Example 3, the g-line reduction projection apparatus is exposed to various focal points, thereby forming a contact hole of 0.35 mu m.

The developing solution was made the same as Example 3 except having changed the addition amount of surfactant. For comparison, a contact hole is likewise formed using a developer containing no surfactant. Scanning electron micrographs of the resist pattern thus developed are shown in FIGS. 15A (resist; MCPRi 6600) and 15B (resist; THMRip 1800). In Figs. 15A and 15B, " F-value " is a quantity indicating a focus position, and in this embodiment, +0.7 mu m represents the best focus position.

As is apparent from FIGS. 15A and 15B, when the contact hole is formed, a sharp pattern can be formed even when the defocusing amount is large by using the developer of the present embodiment, and only a focus margin of 0.5 占 퐉 has been conventionally obtained. In contrast, it was found that a large focus margin of 1 µm was obtained.

As described above, by the lithography developer and lithography process of the present invention, in the ultra-high density integrated semiconductor process, all microresist patterns having different sizes and shapes can be formed as originally designed, and thus ultra high density It is possible to realize ultra-high speed LSI.

Claims (14)

In the developer for lithography used for developing a resist pattern having regions of different sizes and shapes by dissolving and removing the resist region of the resist layer formed on the resist pattern, the developer is represented by the following general formula (I). HO (CH ₂ CH ₂ O) _a (CH (CH ₃ ) CH ₂ O) _b (CH ₂ CH ₂ O) _c ) H. … … … … … … … … … (Ⅰ) (Wherein a, b and c are integers), and the surfactant is a molecular weight of HO (CH ₂ CH ₂ O) a in the general formula (I). When the molecular weight of (CH (CH ₃ ) CH ₂ O) _b is B and the molecular weight of (CH ₂ CH ₂ O) _c H is C, (A + C) / (A + B + C) ≤0.2 The surfactant is lithography developer, characterized in that to increase the dissolution of the resist of the resist area to be dissolved and removed small dissolution removal area on the surface of the resist layer. The developing solution for lithography according to claim 1, wherein the surfactant is an antifoaming surfactant. The developer for lithography according to any one of claims 1 to 3, wherein the concentration of the surfactant is 300 ppm or more. The developer for lithography according to claim 1, wherein the surfactant has a molecular weight of 4,000 or less. The developer for lithography according to claim 1, wherein the concentration of the surfactant is 100 to 1,000 ppm. In the lithography process including the step of dissolving and removing a resist region of a resist layer formed on a resist pattern in order to develop a resist pattern having regions of different size and shape, the following general formula (I) HO (CH ₂ CH ₂ O) _a (CH (CH ₃ ) CH ₂ O) _b (CH ₂ CH ₂ O) _c ) H. … … … … … … … … … (Ⅰ) In the formula, a, b and c are integers, and a lithography developer consisting of a basic solution of a surfactant is used for at least part of the resist pattern development, and the surfactant is represented by the general formula (I). When the molecular weight of HO (CH ₂ CH ₂ O) _a is A, the molecular weight of (CH (CH ₁ ) CH | ₂ O) _b is B, and the molecular weight of (CH ₂ CH ₂ O) _c H is C, (A + B) / (A + B + C) ≤0.2 And the surfactant can increase the dissolution of the resist in the resist region to be dissolved and removed with a small dissolution removal area on the surface of the resist layer. The lithography process according to claim 6, wherein the surfactant is an antifoaming surfactant. The lithography process according to any one of claims 6 to 7, wherein the concentration of the surfactant is 300 ppm or more. The lithography process according to claim 6, wherein the surfactant has a molecular weight of 4,000 or less. The lithography process according to claim 18, wherein the concentration of the surfactant is 100 to 1,000 ppm. The lithography process according to any one of claims 6, 7, 9, and 10, wherein the resist pattern has a resist area of 0.5 mu m or less in size. The lithography process according to any one of claims 6, 7, 9, and 10, wherein the resist is exposed using a g-ray or i-ray reduction projection exposure apparatus. The method according to any one of claims 6, 7, 9, and 10, wherein the surfactant adsorbed on the resist surface or the resist lower substrate is washed and removed with ultrapure water containing ozone of 0.1 ppm or more. Lithography Process. The lithography process according to claim 13, wherein the ozone concentration in the ultrapure water is 2.0 ppm or more.