CN100535753C - Immersion lithography system and method for illuminating semiconductor structure with photoresist layer - Google Patents

Abstract

The invention provides an immersion lithography system and a method for illuminating a semiconductor structure with a photoresist layer. The lithography system is comprised of an optical surface, an immersion fluid in contact with a portion of the optical surface and having a pH of less than 7, and a semiconductor structure having a photoresist layer formed on an upper surface thereof, wherein a portion of the surface of the photoresist layer is in contact with the immersion fluid. In addition, the invention also provides an irradiation method of the semiconductor structure with the photoresist layer formed on the upper surface, which comprises the following steps: firstly, injecting infiltration fluid with the pH value less than 7 between the optical element and the photoresist layer; then, light is irradiated onto the photoresist layer through the immersion fluid, wherein the wavelength of the light is preferably less than 450 nm. The photoetching system and the illumination method provided by the invention not only improve the resolution ratio, but also can prevent the immersion fluid from polluting the photoresist layer or the optical lens.

Description

Immersion photolithography system and method for illuminating semiconductor structures with photoresist layers

technical field

The invention relates to a manufacturing process of a semiconductor element, in particular to a system and a method of an immersion photolithography technology and an immersion fluid used therein.

Background technique

In a typical photolithography system, in order to distinguish high-resolution patterns such as dots, lines or images, the photolithography system must have high resolution. In photolithography systems used in the integrated circuit (IC) industry, light is typically projected directly onto a photoresist layer to pattern electrode elements. Lithography systems have been used in the IC industry for decades and are expected to address processes below 50nm line width. Therefore, improving the resolution of the lithography system has become one of the most important issues for semiconductor IC chip manufacturers to manufacture high-density, high-speed semiconductor IC chips.

For a photolithography system, its resolution R is determined by the formula R=k ₁ λ/NA. Among them, k ₁ is the lithography constant, λ is the wavelength of the image light source, NA is the numerical aperture, calculated by the formula NA=nsinθ, where θ is the half-open aperture of the system center angle, and n is the distance between the lithography system and the substrate The refractive index of the material.

Generally, there are three methods that can be used to adjust the resolution of photolithography etching to improve photolithography. The first method is to reduce the wavelength λ of the image light source. For example, an argon fluorine excimer laser (λ=193 nm) is used instead of G-rays (λ=436 nm) to reduce the wavelength. Recently, the wavelength of imaging light sources has been reduced to 157 nm, and even reduced to extreme ultraviolet (EUV) wavelengths. The second method is to reduce the value of the photoresist constant _k1 , for example, the value of _k1 can be reduced from 0.6 to 0.4 using a phase shift mask and off-axis illumination. The third method is to increase the value of numerical aperture NA by improving optical design, manufacturing technology and metrology control. Currently, the value of numerical aperture NA has been increased from 0.35 to about 0.8. However, the common methods for improving the resolution mentioned above are approaching the physical and technical limits. For example, the value of NA (ie, nsinθ) is limited by n. If an optical system with free space is used, n is equal to 1 at this time, that is, the upper limit of NA is 1.

In recent years, immersion lithographic technology has been developed to allow a further increase in the value of NA (Numerical Aperture) relative to general photolithographic technology. In immersion lithography, the substrate is immersed in a liquid with a high refractive index or an immersion fluid for lithography, and the fluid with a high refractive index (n>1) will fill the outermost optical unit of the lithography system (such as a lens) and the substrate (which is originally filled with air), therefore, using this method, the lens can have an NA value greater than 1. Perfluoropolyether (PFPE), cyclooctane, deionized water (DI-water) and other fluids with high refractive index can be used in immersion lithography. Since the NA value breaks through the original upper limit 1, compared with general photolithography technology, immersion photolithography technology can provide more precise photolithography manufacturing resolution.

A high-refractive-index fluid for immersion lithography should meet several requirements: the fluid must have a low absorption coefficient for the light of the specific wavelength used; the fluid must have a moderately high refractive index to correct the overall system The refractive index; the fluid must have chemical compatibility and good contact with the optical device (lens) and the photoresist on the substrate.

The following summarizes the documents pertaining to immersion lithography:

(1) Publication No. US 2002/0163629 US Patent Methods and apparatus employing an index matching medium.

(2) The US Patent No. US5900354 for Method for Optical Inspection and Lithography.

(3) The U.S. Patent No. US5610683 Immersion typeprojection exposure apparatus.

(4) The US Patent No. US5121256 Lithography system employing a solid immersion lens.

(5) J.A. Hoffnagle et al. Liquid immersion Deep-ultraviolet interferometric lithography. J. Vacuum Science and technology B, Vol.17, No.6, pp:3306-3309:1999.

(6) M. Switkes et al. Immersion lithography at 157nm. J. Vacuum Science and technology B, Vol.19, No.6, pp:2353-2356:1999.

The traditional immersion lithography technology uses water as the immersion fluid, but the pH value of the water used as the immersion fluid has not been further controlled. As a result, photoresists (especially chemically amplified photoresists) used in photolithography are contaminated with hydroxide ions (OH ⁻ ) from wetting fluids or water. In addition, the materials used in some optical lenses, such as calcium fluoride, also have a certain solubility in water.

Therefore, developing better immersion lithography techniques and methods to improve the problems caused by existing techniques is an urgent research issue in semiconductor technology.

Contents of the invention

In view of this, the purpose of the present invention is to provide an immersion photolithography system, an immersion fluid suitable for an immersion photolithography system, and a method for illuminating a semiconductor structure with a photoresist layer formed thereon, which not only improves the immersion photolithography The resolution of the system is improved, and the contamination of the photoresist layer by the immersion fluid and the dissolution of the optical lens are reduced.

In order to achieve the above object, the present invention provides an immersion photolithography system, comprising: an optical surface, wherein the optical surface contains calcium fluoride or magnesium fluoride; and an immersion fluid with a pH value less than 7, wherein the immersion fluid In contact with at least a portion of the optical surface, wherein a fluorine-containing compound is dissolved in the wetting fluid, the concentration of fluoride ions in the wetting fluid is greater than 0.01 mol/liter.

According to the immersion photolithography system of the present invention, the immersion fluid includes water.

According to the immersion photolithography system of the present invention, the pH value of the immersion fluid is between 2 and 7.

According to the immersion photolithography system of the present invention, the pH value of the immersion fluid is between 4-7.

According to the immersion photolithography system of the present invention, the pH value of the immersion fluid is between 6 and 7.

According to the immersion photolithography system of the present invention, the optical surface comprises silicon dioxide.

According to the immersion photolithography system of the present invention, the optical surface further includes molten silicon.

According to the immersion photolithography system of the present invention, the fluorine-containing compound is dissolved in the immersion fluid.

According to the immersion photolithography system of the present invention, the fluorine-containing compound is formed by mixing one or more of sodium fluoride, potassium fluoride and hydrofluoric acid.

According to the immersion photolithography system of the present invention, the concentration of fluoride ions in the immersion fluid is greater than 0.1 mol/liter.

According to the immersion photolithography system of the present invention, there is a semiconductor element substrate under the optical surface, and the uppermost layer of the semiconductor element substrate has a photoresist layer.

According to the immersion photolithography system of the present invention, the photoresist layer includes chemically amplified photoresist.

According to the immersion photolithography system of the present invention, the semiconductor element substrate is immersed in the immersion fluid.

According to the immersion photolithography system of the present invention, a support base is provided under the semiconductor element substrate, and the support base is immersed in the immersion fluid.

In order to achieve the above object, the present invention also provides an immersion photolithography system, which is characterized in that the immersion photolithography system comprises: an optical surface, wherein the optical surface contains calcium fluoride; an immersion fluid with a pH value less than 7 , wherein the immersion fluid is in contact with at least a portion of the optical surface, wherein a fluorine-containing compound is dissolved in the immersion fluid, the concentration of fluoride ions in the immersion fluid is greater than 0.01 moles/liter; and a wavelength is less than 197 nanometers The image light source, wherein, there is a semiconductor element substrate under the optical surface, and the uppermost layer of the semiconductor element substrate has a photoresist layer.

According to the immersion photolithography system of the present invention, the pH value of the immersion fluid is between 6 and 7.

According to the immersion photolithography system of the present invention, the fluorine-containing compound is dissolved in the immersion fluid, and the fluorine-containing compound is obtained by mixing one or more of sodium fluoride, potassium fluoride, and hydrofluoric acid. into.

According to the immersion photolithography system of the present invention, the concentration of fluoride ions in the immersion fluid is greater than 0.01 mol/liter.

In order to achieve the above object, the present invention provides a method for illuminating a semiconductor structure on which a photoresist layer is formed, comprising: introducing an immersion fluid with a pH value less than 7 into the space between the optical surface and the photoresist layer, wherein the The optical surface comprises calcium fluoride or magnesium fluoride; and providing a light energy directly passing through the immersion fluid to irradiate the photoresist layer, wherein the immersion fluid is dissolved with fluorine-containing compounds, and the fluoride ions in the immersion fluid The concentration is greater than 0.01 mol/L.

According to the method of illuminating a semiconductor structure with a photoresist layer formed thereon according to the present invention, the pH value of the wetting fluid is between 2 and 7.

According to the method of illuminating the semiconductor structure on which the photoresist layer is formed according to the present invention, the pH value of the wetting fluid is between 6 and 7.

According to the method for illuminating a semiconductor structure with a photoresist layer formed thereon in the present invention, a fluorine-containing compound is dissolved in the wetting fluid, and the fluorine-containing compound is formed from sodium fluoride, potassium fluoride, hydrofluoric acid One or more of them are mixed.

According to the method of illuminating a semiconductor structure on which a photoresist layer is formed according to the present invention, the concentration of fluorine ions in the wetting fluid is greater than 0.1 mol/liter.

According to the method for illuminating a semiconductor structure on which a photoresist layer is formed according to the present invention, the photoresist layer includes a chemically amplified photoresist.

According to the method for illuminating a semiconductor structure on which a photoresist layer is formed according to the present invention, the method for illuminating light further includes developing the photoresist layer.

According to the method of illuminating the semiconductor structure on which the photoresist layer is formed according to the present invention, the step of developing the photoresist layer includes soaking the photoresist layer in tetramethylammonium hydroxide solution.

The immersion photolithography system provided by the present invention and the method for illuminating the semiconductor structure with the photoresist layer formed thereon improve the refraction of the material between the photolithography system and the semiconductor structure by introducing the immersion fluid between the optical surface and the photoresist layer rate, thereby improving the resolution of the lithography system. At the same time, because the pH value of the immersion fluid is less than 7, the pollution of the photoresist layer by hydroxide ions in the immersion fluid is suppressed, and the accuracy of the subsequent process is improved; since the ions contained in the optical lens material are introduced into the immersion fluid, The same ion effect is used to suppress the dissolution of the immersion fluid to the optical lens and reduce the damage of the immersion fluid to the optical lens.

Description of drawings

FIG. 1 is a schematic diagram of the immersion photolithography system of the present invention.

2a and 2b are schematic diagrams illustrating the interaction between hydroxide ions (OH ⁻ ) of an immersion fluid (such as water) and a photoresist layer (photosensitive material) to be exposed.

Fig. 3a is a schematic diagram of a T-shaped cross-section of a photoresist layer polluted by alkali (hydroxide ions, OH ^- ) in the immersion fluid.

FIG. 3 b is a schematic diagram of a better photoresist profile for a photoresist layer that is not polluted by alkali (hydroxide ions, OH ⁻ ) in the immersion fluid.

Figures 4a and 4b are schematic illustrations of the interaction between hydrogen ions (H ⁺ ) of an wetting fluid (eg water) and an optical element (lens material).

Fig. 5 is a graph showing the relationship between the pH value of the immersion fluid and the solubility of the calcium fluoride lens.

Fig. 6 is the relationship curve between the concentration of F ^- in the immersion fluid and the solubility of calcium fluoride lens.

Detailed ways

The following are preferred embodiments of the present invention to illustrate the immersion photolithography system and its usage according to the present invention.

FIG. 1 is a schematic diagram of one embodiment of an immersion lithography system 10 . The immersion lithography system 10 includes an image light source 20, the light source 20 emits a light energy beam 21, and passes through a lens 22, then the light energy beam 21 passes through a shield 30 and an optical element module 40, and finally passes through a The outermost lens 50 of the optical surface 51 . The space between the outermost lens 50 and the photosensitive material 70 formed on the semiconductor element substrate 80 is filled with the immersion fluid 60 .

In a preferred embodiment, the semiconductor element substrate 80 may be a semiconductor substrate on which an integrated circuit is formed. For example, the semiconductor element substrate 80 may be a silicon substrate (such as a single crystal silicon substrate or a silicon-on-insulator) with transistors.

Photosensitive material 70 may be a photoresist layer or other shielding material. In a preferred embodiment, the photosensitive material 70 can be patterned into a very small size, and the patterned photosensitive material layer with a very small size can be used, for example, to form an etch mask for polysilicon lines (or other conductive materials) It can also be used to make metal oxide semiconductor (MOS) gates with a length of less than 50 nanometers. In addition, the patterned photosensitive material layer can also be used to make metal wires (such as copper damascene wires) with a size of about 200 nanometers or less.

The semiconductor element substrate 80 is supported by a wafer support stand 85 . As shown in FIG. 1 , the immersion fluid 60 is located between the outermost lens 50 and the photosensitive material 70 . In order to simplify the figure and highlight the gist of the present invention, FIG. 1 only shows the wetting fluid 60 between the outermost lens 50 and the photosensitive material 70 . However, both the substrate 80 and/or the pedestal 85 can be immersed in the immersion fluid 60 during the patterning process of the photosensitive material 70 .

FIG. 2 a is an enlarged schematic view of the outermost lens 50 , the photosensitive material 70 and the immersion fluid 60 between them in the photolithography system 10 . The outermost lens 50 is in contact with the immersion fluid 60 . In conventional photolithography systems, the immersion fluid 60 is water. But other fluids, such as cyclooctane and perfluoropolyether (PFPE), can also be used as the immersion fluid 60 . The immersion fluid 60 contains hydroxide ions (OH ⁻ ). If the wetting fluid 60 is water, hydroxide ions will exist due to the dissociation of water, and the equilibrium equation is as follows:

H ₂ O ₍₁₎ →H ⁺ _(aq) +OH ^- _(aq) (Formula I)

Among them, H ⁺ is a hydrogen ion, OH ^- is a hydroxide ion. Symbols 1 and aq represent liquid and aqueous solution states, respectively. The immersion fluid 60 is in contact with the upper surface 90 of the photosensitive material 70 , as shown in FIG. 2 a , at an interface 90 with a portion of the photosensitive material or photoresist 70 . Wherein, the photosensitive material 70 can be a photoresist layer with a wavelength of 193 nm, 157 nm or less as the image light source.

When a predetermined area of the photosensitive material 70 is exposed to a certain dose of light energy beam 21, the exposed portion of the photosensitive material 70 will generate a photocatalyst. The photosensitive material 70 can be chemically amplified (CA) photoresist, which is widely used in photolithography technology with a wavelength of 193 nm or 157 nm. Catalysts produced by exposure are generally acid-releasing catalysts, denoted HA. For example, the catalyst HA will protonate the ester functional group of a photoresist polymer material to form a more soluble acid, and at the same time regenerate protons or hydrogen ions (H ⁺ ), which will deprotonate other The ester functionality then regenerates other acids which dissolve and regenerate H ⁺ . This sequential reaction of protonation, formation of soluble acids, and regeneration of protons is called a chemical amplification reaction.

FIG. 2 b is an enlarged perspective view 100 of the interface 90 between the immersion fluid 60 (water) and the exposed photosensitive material 70 . It is worth noting that acid-releasing catalysts may exist as HA or dissociate into H ⁺ and ^A- forms. It has been mentioned in the background technology section that if there is a large amount of hydroxide ions in the immersion fluid 60, it is very unfavorable, because the hydroxide ions 110 in the immersion fluid 60 will diffuse to the surface of the photosensitive material 70 in contact with the immersion fluid 60, And neutralize acid catalysts. Therefore, in the region where the photosensitive material 70 is in contact with the immersion fluid 60 , the acid catalyst produced by the photosensitive material 70 is consumed, resulting in a decrease in the chemically amplified reaction rate of the photosensitive material 70 near the interface 90 .

As shown in FIG. 3 a , after the exposed photosensitive material 70 (photoresist) is developed with a developing solution such as tetramethylammonium hydroxide (TMAH), the exposed portion 200 of the photoresist will be dissolved. However, due to the low chemical amplification reaction rate of the exposed photosensitive material 70 in the region adjacent to the interface 90, its dissolution range in the developing step becomes smaller, resulting in a T-shaped profile of the photoresist line 210, as shown in FIG. 3a . Therefore, if the acid catalyst on the surface of the photosensitive material is continuously neutralized, the patterned photosensitive material 70 will have a wider line width L1.

According to a preferred embodiment of the present invention, the concentration of OH ^- ions in the immersion fluid 60 is controlled at 10 ^-7 mol/L (or mol/dm ³ , where mol, L and dm represent moles, liters and decimeters, respectively) . The invention reduces the concentration of OH ^- ions to less than 10 ^-7 mol/L, so that the consumption of the acid catalyst in the exposed area of the photoresist surface can be suppressed. Therefore, by reducing the concentration of OH ⁻ ions and the amount of OH ⁻ ions diffused into the photoresist, the patterned photosensitive material 220 has a better line width L2 as shown in FIG. 3 b.

Adding an excess of protons or hydrogen ions to the immersion fluid 60 is one way to reduce the concentration of ^OH- ions in the water. The addition of additional hydrogen ions to the water shifts the equilibrium of Equation I to the left so that the concentration of OH ^- ions is less than 10 ^-7 mol/L. Adding acid to the immersion fluid 60 can change the concentration of hydrogen ions in the immersion fluid 60, and the type of acid can be organic acids such as acetic acid or formic acid, or inorganic acids such as dilute hydrochloric acid or dilute sulfuric acid, and can also be used in combination.

Therefore, according to a preferred embodiment of the present invention, the immersion fluid 60 has an excess concentration of hydrogen ions to reduce the concentration of hydroxide ions in the equilibrium equation. According to the present invention, the preferred value of the concentration of hydrogen ions in the immersion fluid 60 should be greater than 10 ^-7 mol/L, that is, the pH value of the immersion fluid 60 is preferably less than 7, and the concentration of hydrogen ions at room temperature (300K) The preferred range is about 10 ^-7 mol/L to 10 ^-7 mol/L, or 10 ^-7 mol/L to 10 ^-4 mol/L, or 10 ^-7 mol/L to 10 ^-5 mol/L, The optimal range is about 10 ^-7 mol/L to 10 ^-6 mol/L. Within the above-mentioned hydrogen ion concentration range, the pH value of the immersion fluid 60 is less than 7, preferably between 2 and 7, more preferably between 4 and 7 or between 5 and 7, and most preferably between about 5 and 7. between 6 and 7. The definition of pH is -log[H ⁺ ], where [H ⁺ ] is the molar concentration of hydrogen ions. Adding acid to the immersion fluid 60 can further improve the chemical amplification effect of the photoresist.

4a is a cross-sectional view of the wetting fluid 60 (ie water) in contact with the outermost lens 50, and FIG. 4b is an enlarged perspective view 300 of the wetting fluid 60 (ie water) and the optical surface 51 of the outermost lens 50. The surface of the outermost lens 50 may have a very small part dissolved in the immersion fluid 60, and the lens material may be silicon dioxide, fused silica, magnesium fluoride (MgF ₂ ) or calcium fluoride (CaF ₂ ). Taking the calcium fluoride lens material used in a preferred embodiment of the present invention as an example, it will form calcium ions (Ca ²⁺ ) and fluorine ions (F ^- ) after being dissolved in water, as shown below:

CaF _2(s) → Ca ²⁺ _(aq) +2F ^- _(aq) (Formula II)

At room temperature, 1 liter of water with a pH value of 7 can dissolve about 3×10 ^-4 moles of solid calcium fluoride. Due to the continuous flow of the immersion fluid, the calcium fluoride lens material is dissolved in the water at a fixed concentration and then carried away by the water. The amount dissolved will increase with the age of the instrument (eg, several years). If the solubility of the lens material is different in different lens regions, it will cause deformation of the lens surface, and even cause image distortion and instrument failure.

Figure 5 is the molar solubility of _CaF2 in water at different pH (or acidity). When the pH value of water decreases from 7, that is, the acidity increases, the solubility of CaF ₂ will also increase, and when the pH value is less than 4, the increase of CaF ₂ solubility is more significant. The increase in the solubility of calcium fluoride in acidic water is mainly due to the increase in the concentration of hydrogen ions. If there is an excess of hydrogen ions, hydrogen ions (H ⁺ ) are easy to combine with fluoride ions (F ^- ) to shift the balance to the right, resulting in hydrofluoric acid (HF) aqueous solution:

H ⁺ _(aq) +F ^- _(aq) → HF _(aq) (Formula III)

Because fluoride ions are consumed in generating hydrofluoric acid, the equilibrium of Equation II will shift to the right, causing more _CaF2 solids to dissolve, which will accelerate the loss of lens _CaF2 material. Therefore, when the pH value is maintained below 7, although the impact on acid catalyst consumption can be reduced, the pH value should not be too low, otherwise it will cause severe dissolution of the _CaF2 lens material. Therefore, the pH value of the immersion fluid described in the present invention is generally within the range of less than 7, preferably 2-7, more preferably 4-7, and most preferably 5-7, even 6-7.

It can be seen from another preferred embodiment of the present invention that the solubility of lens materials can be reduced by using the same ion effect. For example, if the material of the outermost lens 50 is CaF ₂ , the dissolution of CaF ₂ can be suppressed by making the immersion fluid 60 (water) contain a certain concentration of fluorine ions. According to the same ion effect, the additional added fluoride ions would shift the formula II to the left, thus effectively inhibiting the dissolution of _CaF2 .

As shown in FIG. 6, as the concentration of fluoride ions in the immersion fluid 60 increases, the molar solubility of _CaF2 decreases. The specific method can be to add highly soluble fluorine-containing compounds in water, such as sodium fluoride, potassium fluoride, hydrofluoric acid or a mixture of the above substances. In another preferred embodiment of the present invention, the fluorine-containing compound is preferably hydrofluoric acid, more preferably a mixture of hydrofluoric acid and sodium fluoride. The immersion fluid of the present invention has a fluoride ion concentration greater than 0.01 mol/L, preferably greater than 0.05 mol/L, and optimally greater than 0.1 mol/L.

In addition, it is worth noting that the immersion lithography system described in the present invention may also include other known methods applicable to immersion lithography techniques, for example, the immersion lithography system may be exposed on the outermost lens and Part of the wafers are soaked with the immersion fluid, or the entire wafer is soaked in the immersion fluid, or the whole base is soaked in the immersion fluid.

Although the present invention has been described above through preferred embodiments, the preferred embodiments are not intended to limit the present invention. Those skilled in the art should be able to make various changes and supplements to the preferred embodiment without departing from the spirit and scope of the present invention. Therefore, the scope of protection of the present invention is subject to the scope of the claims.

A brief description of the symbols in the drawings is as follows:

10: Immersion lithography system 22: Lens

20: image light source 30: shielding

21: Light energy beam 40: Optical component module

50: Outermost lens 100: Magnified perspective view

51: Optical surface 110: Hydroxide diffused into photosensitive material

60: Wetting Fluid Ions

70: Photosensitive material 200: Photoresist exposed part

80: Semiconductor element substrate 210: Photoresist line with T-shaped section

85: Wafer support pedestal 220: Photoresist line

90: Upper surface of photosensitive material 300: Enlarged perspective view

Claims (22)

1. immersion lithography system is characterized in that this immersion lithography system comprises:

An optical surface, wherein said optical surface comprises calcium fluoride or magnesium fluoride; And

PH value wherein should be soaked into fluid and contact with the some of this optical surface at least less than 7 infiltration fluid, was dissolved with fluorine-containing compound in the wherein said infiltration fluid, and the concentration of fluorine ion is greater than 0.01 mol in the described infiltration fluid.

2. immersion lithography system according to claim 1 is characterized in that: described infiltration fluid comprises water.

3. immersion lithography system according to claim 2 is characterized in that: the pH value of described infiltration fluid is between 2 to 7.

4. immersion lithography system according to claim 3 is characterized in that: the pH value of described infiltration fluid is between 4 to 7.

5. immersion lithography system according to claim 4 is characterized in that: the pH value of described infiltration fluid is between 6 to 7.

6. immersion lithography system according to claim 1 is characterized in that: described fluorochemicals is to be mixed by in sodium fluoride, potassium fluoride, the hydrofluorite one or more.

7. immersion lithography system according to claim 1 is characterized in that: the concentration of fluorine ion is greater than 0.1 mol in the described infiltration fluid.

8. immersion lithography system according to claim 1 is characterized in that: described optical surface below has a semiconductor element substrate, and the superiors of this semiconductor element substrate have a photoresist layer.

9. immersion lithography system according to claim 8 is characterized in that: described photoresist layer comprises the chemical amplification type photoresistance.

10. immersion lithography system according to claim 8 is characterized in that: described semiconductor element substrate soaks in described infiltration fluid.

11. immersion lithography system according to claim 8 is characterized in that: have supporting platform seat below the described semiconductor element substrate, this supporting platform seat is soaked in described infiltration fluid.

12. an immersion lithography system is characterized in that this immersion lithography system comprises:

An optical surface, wherein said optical surface comprises calcium fluoride;

PH value wherein should be soaked into fluid and contact with the some of this optical surface at least less than 7 infiltration fluid, was dissolved with fluorine-containing compound in the wherein said infiltration fluid, and the concentration of fluorine ion is greater than 0.01 mol in the described infiltration fluid; And

Wavelength is less than the image light source of 197 nanometers,

Wherein, described optical surface below has a semiconductor element substrate, and the superiors of this semiconductor element substrate have a photoresist layer.

13. immersion lithography system according to claim 12 is characterized in that: the pH value of described infiltration fluid is between 6 to 7.

14. immersion lithography system according to claim 12 is characterized in that: this fluorochemicals is to be mixed by in sodium fluoride, potassium fluoride, the hydrofluorite one or more.

15. one kind to the top irradiation method that is formed with the semiconductor structure of photoresist layer, it is characterized in that this irradiation method comprises:

Import a pH value in the space between optical surface and photoresist layer less than 7 infiltration fluid, wherein said optical surface comprises calcium fluoride or magnesium fluoride; And

Provide a luminous energy directly to pass this infiltration fluid and shine on this photoresist layer, be dissolved with fluorine-containing compound in the wherein said infiltration fluid, the concentration of fluorine ion is greater than 0.01 mol in the described infiltration fluid.

16. according to claim 15 to the top irradiation method that is formed with the semiconductor structure of photoresist layer, it is characterized in that: the pH value of described infiltration fluid is between 2 to 7.

17. according to claim 16 to the top irradiation method that is formed with the semiconductor structure of photoresist layer, it is characterized in that: the pH value of described infiltration fluid is between 6 to 7.

18. according to claim 15 to the top irradiation method that is formed with the semiconductor structure of photoresist layer, it is characterized in that: this fluorochemicals is to be mixed by in sodium fluoride, potassium fluoride, the hydrofluorite one or more.

19. according to claim 15 to the top irradiation method that is formed with the semiconductor structure of photoresist layer, it is characterized in that: the concentration of fluorine ion is greater than 0.1 mol in the described infiltration fluid.

20. according to claim 15 to the top irradiation method that is formed with the semiconductor structure of photoresist layer, it is characterized in that: described photoresist layer comprises the chemical amplification type photoresistance.

21. according to claim 15 to the top irradiation method that is formed with the semiconductor structure of photoresist layer, it is characterized in that: this irradiation method also comprises develops to described photoresist layer.

22. according to claim 21 to the top irradiation method that is formed with the semiconductor structure of photoresist layer, it is characterized in that: described photoresist layer is carried out step of developing comprise described photoresist layer is infiltrated on the tetramethyl Dilute Ammonia Solution.

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