JP2012049305A - Vacuum ultraviolet light processor - Google Patents

Abstract

An object of the present invention is to uniformly treat a light intensity distribution of vacuum ultraviolet light applied to a material to be treated, and to treat the material to be treated highly uniformly.
A light source that irradiates vacuum ultraviolet light, a stage on which a material to be processed is placed, an in-plane light intensity of vacuum ultraviolet light that is disposed between the stage and the light source and is irradiated on the surface of the material to be processed. A correction member for correcting the distribution is provided, and the in-plane transmittance is adjusted by the correction member, and the processed member is irradiated with vacuum ultraviolet light having a uniform light intensity.
[Selection] Figure 1

Description

  The present invention relates to a vacuum ultraviolet light processing apparatus that can uniformly irradiate vacuum ultraviolet light (VUV light: light having a wavelength of 200 nm or less in ultraviolet light).

  A conventional vacuum ultraviolet light processing apparatus using an excimer lamp or the like having a wavelength of 200 nm or less uses, for example, a light source in which a plurality of tubular excimer lamps are juxtaposed on a wafer to be processed as shown in Patent Document 1. In general, the wafer is processed by irradiation with vacuum ultraviolet light.

  It is desired that the vacuum ultraviolet light to be irradiated irradiates the surface of the wafer, which is a material to be processed, with a uniform intensity so that the wafer is processed uniformly.

  Patent Document 2 discloses a lamp device that considers the uniformity of the irradiation light intensity of the vacuum ultraviolet light to be irradiated. In this example, it is disclosed that a plurality of cylindrical dielectric barrier discharge lamps are juxtaposed and a substantially V-shaped light reflecting plate is provided between adjacent lamps.

  Patent Document 3 discloses that a stage on which a wafer is placed is rotated or translated with respect to a lamp in order to obtain uniformity of irradiation light intensity of vacuum ultraviolet light.

JP 2005-158796 A JP-A-8-153493 JP 2005-197348 A

  Patent Document 1 discloses that a wafer, which is a material to be processed, is irradiated with vacuum ultraviolet light using a light source in which a plurality of tubular excimer lamps are juxtaposed to process the wafer. However, no mention is made of the uniformity of the irradiation intensity of the vacuum ultraviolet light within the wafer surface and the uniformity of the wafer processing associated therewith.

  In Patent Document 2, a plurality of cylindrical dielectric barrier discharge lamps are juxtaposed, and a substantially V-shaped light reflecting plate is provided between adjacent lamps. In this example, the uniformity of the irradiation intensity of the vacuum ultraviolet light within the wafer surface is not sufficient. That is, consideration is given to the uniformity in the direction orthogonal to the axis of the cylindrical lamp (the direction in which a plurality of lamps are arranged). However, no consideration is given to the in-wafer uniformity of the irradiation light intensity in the axial direction of the cylindrical lamp when the distance between the cylindrical lamp and the wafer is large.

  As described above, Patent Document 3 discloses that a wafer stage is rotated or translated with respect to a lamp in order to obtain uniformity of irradiation light intensity of vacuum ultraviolet light.

  When the wafer stage is rotated, the circumferential uniformity is improved, but it is difficult to sufficiently improve the radial uniformity. Particularly in the vicinity of the center, a singular point of light intensity is likely to occur, and it is difficult to irradiate vacuum ultraviolet light highly uniformly over the entire surface of the wafer.

  When the wafer stage is moved in translation, as described above, in the case where the distance between the cylindrical lamp and the wafer is large, the uniformity of the irradiation light intensity in the axial direction of the cylindrical lamp is reduced in the wafer surface. For this reason, when translation is performed in a direction perpendicular to the axial direction of the lamp, which is a general translational direction, the uniformity in the length direction of the lamp is reduced, and vacuum ultraviolet light is highly uniformly distributed over the entire wafer surface. Difficult to irradiate.

  When the material to be processed is a wafer that requires microfabrication, it is essential to reduce minute foreign matter from the viewpoint of yield. In such a case, moving the wafer stage has a high risk of generating foreign matter from the drive unit. In such a case, it is desirable to improve the in-wafer uniformity of the irradiation intensity of the vacuum ultraviolet light with the wafer stage fixed.

  As described above, in a vacuum ultraviolet light processing apparatus using an excimer lamp having a wavelength of 200 nm or less, it is possible to obtain uniformity in wafer surface of the irradiation light intensity of vacuum ultraviolet light, and a sufficient uniformity of wafer processing associated therewith. It is difficult to get.

  The present invention has been made in view of these problems, and provides a vacuum ultraviolet light processing apparatus capable of highly uniformly irradiating vacuum ultraviolet light on the entire surface of the processing material and processing the processing material with high uniformity. To do.

  In order to solve the above problems, the present invention employs the following means.

  A light source that irradiates vacuum ultraviolet light, a stage on which the material to be processed is placed, and an in-plane light intensity distribution of the vacuum ultraviolet light that is disposed between the stage and the light source and is irradiated on the surface of the material to be processed. A correction member is provided, and the in-plane transmittance is adjusted by the correction member, and the processing target member is irradiated with vacuum ultraviolet light having a uniform light intensity.

  Since this invention is provided with the above structure, it can provide the vacuum ultraviolet light processing apparatus which can irradiate vacuum ultraviolet light to the to-be-processed material whole surface highly uniformly, and can process a to-be-processed material highly uniformly.

It is a longitudinal cross-sectional view of the vacuum ultraviolet light processing apparatus which concerns on 1st Embodiment. It is a figure which shows the axial direction cross section of the light intensity distribution correction | amendment window in 1st Embodiment. It is a figure explaining 2nd Embodiment. It is a figure explaining 2nd Embodiment. It is a figure explaining 3rd Embodiment. It is a figure explaining 3rd Embodiment. It is a figure explaining 4th Embodiment. It is a figure which shows the example of the penetration pattern of a light intensity distribution correction | amendment penetration board. It is a figure explaining 5th Embodiment. It is a figure which shows XZ sectional drawing of a light intensity distribution correction window. It is a figure explaining 6th Embodiment. It is a figure explaining 6th Embodiment. It is a figure explaining 7th Embodiment. It is a figure which shows the 1st example of the vacuum ultraviolet light processing apparatus with which this invention is applied. It is the figure which looked at FIG. 14 from the upper part. It is a figure which shows the relationship between the light intensity distribution of vacuum ultraviolet light, and the lamp-wafer distance. It is a figure which shows the relationship between the light intensity distribution of vacuum ultraviolet light, and the lamp-wafer distance. It is a figure which shows the 2nd example of the vacuum ultraviolet light processing apparatus with which this invention is applied. It is a figure which shows the relationship between the light intensity distribution of vacuum ultraviolet light, and the lamp-wafer distance. It is a longitudinal cross-sectional view which shows the 3rd example of the vacuum ultraviolet light processing apparatus to which this invention is applied.

  Hereinafter, embodiments will be described with reference to the accompanying drawings. 14 to 20 are diagrams showing a vacuum ultraviolet light processing apparatus to which the present invention is applied, FIG. 14 is a diagram showing a first example of a vacuum ultraviolet light processing apparatus to which the present invention is applied, and FIG. It is the figure which looked at FIG. 14 from the upper part.

  As shown in the figure, a cylindrical excimer lamp 1 using a dielectric barrier discharge having a wavelength of 200 nm or less is installed in a lamp house 2. As the cylindrical excimer lamp 1, an Xe excimer lamp that emits excimer light having a wavelength of 172 nm is often used. In the processing chamber 4, a wafer 5 which is a material to be processed is placed on a wafer stage 6.

  Here, the diameter of the wafer is 300 mm. Further, a window 3 capable of transmitting the vacuum ultraviolet light is installed between the lamp house 2 and the processing chamber 4 so that the vacuum ultraviolet light emitted from the cylindrical excimer lamp 1 is irradiated onto the wafer 5. ing. As the window material, a flat plate made of synthetic quartz capable of transmitting excimer light having a wavelength of 172 nm was used. The lamp house 2 and the processing chamber 4 are partitioned by a window 3. The lamp house 2 is provided with a gas inlet (not shown) and a gas outlet (not shown). By introducing N 2 gas into the lamp house and replacing the inside of the lamp house 2 with N 2 gas, Attenuation of vacuum ultraviolet light by O2 gas in the air is suppressed.

  In addition, the cylindrical excimer lamp 1 and the window 3 are cooled by introducing N 2 gas, and the transmission limit of the vacuum ultraviolet light is shifted and the light intensity of the vacuum ultraviolet light is reduced due to the temperature rise of the synthetic quartz as the window material. Is suppressed.

  The processing chamber 4 is also provided with a gas inlet (not shown) and a gas outlet (not shown). By introducing N2 gas into the processing chamber 4 and substituting the inside of the processing chamber 4 with N2 gas, attenuation of vacuum ultraviolet light due to O2 gas in the air is suppressed.

  As another example, the inside of the processing chamber 4 can be evacuated by a vacuum exhaust port (not shown) and a vacuum exhaust system (not shown) provided in the processing chamber 4, and the wafer 5 can be irradiated with vacuum ultraviolet light. . As yet another example, the inside of the processing chamber 4 is formed by a vacuum exhaust port (not shown) and a gas introduction port (not shown), a vacuum exhaust system (not shown), and a gas supply system (not shown) provided in the processing chamber 4. After evacuation, a gas is introduced, and the wafer 5 can be irradiated with vacuum ultraviolet light under reduced pressure.

  Under the above circumstances, the wafer stage 6 is driven in the direction (X axis) perpendicular to the axial direction (Y axis) of the cylindrical excimer lamp 1 to scan (sweep) the wafer 5 with respect to the cylindrical excimer lamp 1. Thus, the wafer 5 can be processed by irradiating the entire surface of the wafer 5 with vacuum ultraviolet light.

  FIG. 16 shows a calculation result of the relationship between the light intensity distribution of the vacuum ultraviolet light (X-axis direction) and the lamp-wafer 5 distance (Z-axis direction) at a lamp width (diameter) of 40 mm. FIG. 17 shows the calculation result of the relationship between the light intensity distribution (Y-axis direction) of vacuum ultraviolet light and the lamp-wafer 5 distance (Z-axis direction) at a lamp length of 320 mm.

  For simplicity, it was calculated as (1) the radiated light intensity distribution was uniform under the lamp, (2) no window 3 and (3) no vacuum ultraviolet light attenuation in the gas phase. As shown in FIGS. 16 and 17, as the distance between the lamp and the wafer 5 increases, the light intensity of the vacuum ultraviolet light decreases, and even though it is directly below the lamp, the uniformity deteriorates. This can be understood because the light emission from the lamp is related to the solid angle.

  As shown in FIGS. 14 and 15, even when the wafer 5 is scanned in the direction perpendicular to the axial direction of the cylindrical excimer lamp 1 (X-axis direction) (X-axis direction) as shown in FIG. It turns out that it is difficult to irradiate light and process the wafer uniformly.

  FIG. 18 is a longitudinal sectional view showing a second example of a vacuum ultraviolet light processing apparatus to which the present invention is applied. In this example, a plurality of cylindrical excimer lamps 1 shown in FIG. 14 are arranged in parallel to the lamp axis (in the X-axis direction) in parallel. Further, the opening width of the window 3 is made larger than the diameter of the wafer 5 so that the vacuum ultraviolet light from the plurality of cylindrical excimer lamps 1 can be irradiated to the entire surface of the wafer 5. Thereby, the wafer stage 6 can be fixed. FIG. 19 shows the calculation results of the relationship between the vacuum ultraviolet light intensity distribution (X-axis direction) and the lamp-wafer 5 distance (Z-axis direction) at a lamp width of 40 mm and a lamp interval of 30 mm, as in FIG. Show. Even in the case of this example in which a plurality of cylindrical excimer lamps 1 are arranged, it can be seen from FIG. 19 that it is difficult to uniformly irradiate the entire surface of the wafer 5 with vacuum ultraviolet light and uniformly treat the wafer.

  FIG. 20 is a longitudinal sectional view showing a third example of a vacuum ultraviolet light processing apparatus to which the present invention is applied. In this example, instead of the plurality of cylindrical excimer lamps 1 shown in FIG. A lamp 7 is arranged. Also in this case, the diameter of the window 3 is made larger than the diameter of the wafer 5 and the wafer stage 6 is fixed so that the vacuum ultraviolet light from the disc-shaped excimer lamp 7 can be irradiated to the entire surface of the wafer 5. .

  When the diameter of the disc-shaped excimer lamp 7 is 320 mm, the calculation result (not shown) of the relationship between the light intensity distribution (radial direction) of the vacuum ultraviolet light and the distance between the lamp and the wafer 5 (Z-axis direction) is shown in FIG. However, since the distribution is axially symmetric, the light intensity at the outer peripheral portion is further reduced as compared with FIG. 17, and the uniformity is deteriorated. Therefore, even in the case of this example in which the disk-shaped excimer lamp 7 is arranged, it is found that it is difficult to uniformly irradiate the entire surface of the wafer 5 with vacuum ultraviolet light and uniformly treat the wafer 5.

  As described above, in a vacuum ultraviolet light processing apparatus using an excimer lamp or the like having a wavelength of 200 nm or less, the uniformity of the irradiation light intensity of vacuum ultraviolet light on the wafer surface is not sufficient. For this reason, it is difficult to uniformly irradiate the entire surface of the wafer 5 with vacuum ultraviolet light and treat the wafer 5 uniformly.

  FIG. 1 is a longitudinal sectional view of a vacuum ultraviolet light processing apparatus according to the first embodiment. As shown in FIG. 1, a cylindrical excimer lamp 1 using a dielectric barrier discharge having a wavelength of 200 nm or less is installed in a lamp house 2. In this embodiment, the cylindrical excimer lamp 1 uses an Xe excimer lamp that emits excimer light with a wavelength of 172 nm. However, an Ar excimer lamp with a wavelength of 126 nm, a Kr excimer lamp with a wavelength of 146 nm, an ArF excimer lamp with a wavelength of 193 nm, Other vacuum ultraviolet light sources may be used.

  In the processing chamber 4, a wafer 5 that is a material to be processed is placed on a wafer stage 6. In the present embodiment, the diameter of the wafer is 300 mm. Further, between the lamp house 2 and the processing chamber 4, a light intensity distribution that transmits the radiated vacuum ultraviolet light so that the vacuum ultraviolet light radiated from the cylindrical excimer lamp 1 is uniformly irradiated on the wafer 5. A correction window 8 is provided.

  As the window material of the light intensity distribution correction window 8, a synthetic quartz flat plate capable of transmitting excimer light having a wavelength of 172 nm is used, but other materials that transmit vacuum ultraviolet light such as MgF2, CaF2, LIF, and sapphire are used. May be. However, since the transmission spectrum of vacuum ultraviolet light differs depending on the material, it is necessary to select a material that transmits light from the vacuum ultraviolet light source to be used.

  The lamp house 2 and the processing chamber 4 are partitioned by a light intensity distribution correction window 8. The lamp house 2 is provided with a gas inlet (not shown) and a gas outlet (not shown). By introducing N 2 gas into the lamp house 2 and replacing the inside of the lamp house 2 with N 2, vacuum ultraviolet light is obtained. The attenuation by O2 in the air is suppressed. At this time, the lamp and the light intensity distribution correction window 8 are cooled by the introduced N 2 gas. As a result, it is possible to suppress a decrease in the light intensity of the vacuum ultraviolet light accompanying a shift in the transmission limit of the vacuum ultraviolet light due to the temperature rise of the synthetic quartz constituting the light intensity distribution correction window 8. As the gas introduced into the lamp house, other rare gases such as He, Ne, Kr, and Ar may be used as long as the attenuation of vacuum ultraviolet light is small. In the case of He, since the heat transfer efficiency is high, the light intensity distribution correction window 8 can be cooled more efficiently.

  Similarly to the lamp house 2, the processing chamber 4 is also provided with a gas inlet (not shown) and a gas outlet (not shown). Therefore, (1) by introducing N2 gas into the lamp house 2 and substituting the inside of the lamp house 2 with N2, attenuation of vacuum ultraviolet light due to O2 in the air can be suppressed. The gas may be another rare gas such as He. (2) Further, a photoexcited reaction gas such as O 2 gas or a photo-assisted surface reaction gas with the wafer 5 can be introduced from a gas inlet (not shown). (3) In another example, the inside of the processing chamber 4 is evacuated by a vacuum exhaust port (not shown) and a vacuum exhaust system (not shown) provided in the processing chamber 4, and the wafer 5 is irradiated with vacuum ultraviolet light. Can do. (4) In yet another example, a processing chamber is provided by a vacuum exhaust port (not shown), a gas inlet (not shown), a vacuum exhaust system (not shown), and a gas supply system (not shown) provided in the processing chamber 4. After the inside of the vacuum chamber 4 is evacuated, a photoexcited reaction gas such as O 2 or a light-assisted surface reaction gas with the wafer 5 is introduced, and the wafer 5 can be irradiated with vacuum ultraviolet light under reduced pressure. In addition, the gas discharged from the lamp house 2 and the processing chamber 4 is discharged after being processed through an exhaust gas processing device (not shown) such as ozone processing as necessary.

  FIG. 2 is a diagram showing an axial cross section (YZ cross section) of the cylindrical excimer lamp 1 of the light intensity distribution correction window 8 in the first embodiment.

  The light intensity distribution in the axial direction (Y-axis direction) of the cylindrical excimer lamp 1 is as shown in FIG. 17 according to the distance between the cylindrical excimer lamp 1 and the wafer 5 when the light intensity distribution correction window 8 is not provided. A convex light intensity distribution is obtained. The lamp length was 320 mm. In the present embodiment, in order to correct the convex light intensity distribution shown in FIG. 17, a light intensity distribution correction window having a convex cross section as shown in FIG. 2 is used.

  The light intensity distribution correction window 8 has a constant light absorption coefficient α, although a material that favorably transmits vacuum ultraviolet light from the cylindrical excimer lamp 1 is selected. In this case, when the light passes through a plate having a thickness t, the light intensity attenuates in proportion to exp (−t / α). Therefore, the light intensity distribution when the distance between the cylindrical excimer lamp 1 and the wafer 5 is set to a predetermined value is obtained by FIG. 17 or by actual measurement. The light having the obtained emission intensity distribution is attenuated according to the attenuation factor exp (−t / α) corresponding to the material constituting the light intensity distribution correction window 8. At this time, the thickness distribution in the Y-axis direction of the light intensity distribution correction window is changed so that the light intensity distribution on the wafer 5 after passing through the light intensity distribution correction window 8 becomes uniform. In this case, it is also preferable to consider changes in transmittance due to multiple reflection at the interfaces on both sides of the light intensity distribution correction window 8, refraction of transmitted light in a convex cross-sectional shape, and the like.

  Note that the lamp house 2 and the processing chamber 4 are separated by a light intensity distribution correction window 8, and foreign substances generated from the lamp house 2 are prevented from flowing into the processing chamber 4. As a result, foreign matter adhering to the wafer 5 can be reduced and the yield can be improved.

  The plate thickness of the light intensity distribution correction window 8 is designed so as to maintain mechanical strength and reduce light attenuation according to the differential pressure between the lamp house 2 and the processing chamber 4. For the seal portion between the light intensity distribution correction window 8 and the processing chamber 4 or the lamp house 2, a seal material, an O-ring or the like (not shown) is selected according to the differential pressure. Further, even if the light intensity distribution correction window 8 is separately provided on the flat window 3 as shown in FIG. 14, the effect of correcting the light intensity distribution can be obtained.

  When irradiating the vacuum ultraviolet light, the wafer stage 6 is driven in a direction (X axis) perpendicular to the length direction (Y axis) of the cylindrical excimer lamp, and the wafer 5 is moved in the X direction relative to the cylindrical excimer lamp. Scan (sweep) in the axial direction. Thereby, the wafer 5 can be processed by irradiating the entire surface of the wafer 5 with vacuum ultraviolet light. Thus, by providing the light intensity distribution correction window 8, it is possible to irradiate vacuum ultraviolet light uniformly in the Y-axis direction, and to scan (sweep) the wafer 5 in the X-axis direction, so that it is uniform in the X-axis direction. Can be irradiated with vacuum ultraviolet light. Therefore, the entire surface of the wafer 5 can be uniformly irradiated with vacuum ultraviolet light, and as a result, the entire surface of the wafer 5 can be processed with high uniformity.

  3 and 4 are diagrams for explaining the second embodiment. In the present embodiment, instead of the light intensity distribution correction window 8 in the first embodiment shown in FIG. 1, a window 3 that transmits vacuum ultraviolet light and a light intensity distribution correction through plate 9 are provided.

  In FIG. 4, the example of the penetration pattern of the light intensity correction penetration board 9 is shown. The light intensity correcting through plate 9 is made of a material that does not transmit VUV light, such as a metal plate, a ceramic plate, a glass plate, or a Si plate. In this embodiment, a thin stainless plate is used. The through plate 9 is a plate structure in which a through mesh or a large number of through holes are formed, and the in-plane light intensity of the transmitted light is changed by changing the in-plane distribution of the through portion so that a desired in-plane light intensity distribution can be obtained. Correct the distribution.

  In the present embodiment, as shown in FIG. 4, a lattice pattern is used, and the lattice spacing A is increased from the center toward the outer periphery so as to correct the convex light intensity distribution shown in FIG. The lattice width B was constant. The penetrating portion may be an arbitrary pattern such as a mesh pattern or a hole-like dot pattern. Note that the surface density or size of patterns such as lattices and holes adjusts the aperture ratio of the light intensity distribution correcting through-hole plate 9 so as to correct the convex light intensity distribution shown in FIG. Since the light intensity distribution correcting through-hole plate 9 is basically made of a material that does not transmit or hardly transmits VUV light, it is designed to increase the aperture ratio as much as possible to increase the transmitted light intensity. When the distance C between the light intensity distribution correcting through-hole plate 9 and the wafer 5 is close, the pattern of the light intensity distribution correcting through-hole plate 9 is transferred. For this reason, it is desirable that the interval C be larger than a portion that does not transmit light (in this case, the lattice width B).

  According to the present embodiment, the same entire surface of the wafer 5 as in the first embodiment can be processed uniformly. Unlike the first embodiment, there is no need to consider correction of the transmittance of vacuum ultraviolet light due to multiple reflection at the interface of the light intensity distribution correction window 8, refraction of the vacuum ultraviolet light, etc., and light intensity distribution correction penetration. The design of the plate 9 is easy.

  5 and 6 are diagrams for explaining the third embodiment.

  In this embodiment, instead of one cylindrical excimer lamp 1 in the first embodiment shown in FIG. 1, a plurality of (four in this embodiment) cylindrical excimer lamps 1 are provided, and vacuum ultraviolet light is further emitted. The diameter D of the opening to be irradiated is made larger than the wafer diameter, and the wafer stage is fixed.

  FIG. 6 shows an XZ sectional view of the light intensity distribution correction window 8. Note that the YZ cross section has the same shape as in FIG.

  When a plurality of cylindrical excimer lamps 1 are arranged side by side as in this embodiment (lamp width 40 mm, lamp interval 60 mm as in the example of FIG. 18), and there is no light intensity distribution correction window 8, The light intensity distribution is a light intensity distribution as shown in FIG. 19 according to the interval between the cylindrical excimer lamp 1 and the wafer 5.

  Therefore, as in the first embodiment, the intensity distribution of the vacuum ultraviolet light applied to the wafer 5 can be uniformly corrected by changing the plate thickness distribution of the light intensity distribution correction window 8.

  Therefore, according to the third embodiment of the present invention, the entire surface of the wafer 5 similar to that of the first embodiment can be processed uniformly. Unlike the first embodiment, since it is not necessary to scan (sweep) the wafer stage, the risk of foreign matter generation due to stage driving is reduced, which is advantageous in improving the yield. Further, since the wafers 5 can be collectively processed without being scanned, the processing speed per wafer is improved, and the throughput is improved.

  7 and 8 are diagrams for explaining a fourth embodiment of the present invention. In this embodiment, instead of the single cylindrical excimer lamp 1 in the second embodiment shown in FIG. 3, a plurality of (four in this embodiment) cylindrical excimer lamps 1 are provided, and vacuum ultraviolet light is provided. The diameter D of the opening that irradiates the wafer is made larger than the wafer diameter, and the wafer stage is fixed.

  In FIG. 8, the example of the penetration pattern of the light intensity distribution correction penetration board 9 is shown. The concept of the material and pattern of the light intensity distribution correcting through-hole plate 9 and the distance between the light intensity distribution correcting through-hole plate 9 and the wafer 5 are the same as those in the second embodiment shown in FIG.

  In this embodiment, as shown in FIG. 8, a grid pattern is used, and the Y-axis direction has a grid interval A from the center to the outer periphery so as to correct the convex light intensity distribution of FIG. In the X-axis direction, the lattice spacing A is periodically changed so as to correct the periodic light intensity distribution of FIG. The lattice width B was constant.

  According to the present embodiment, it is possible to obtain the same operational effects as those of the second embodiment and the third embodiment. Further, the light intensity distribution correcting through-hole plate 9 can be easily designed, the risk of foreign matter generation can be reduced, the processing throughput of the wafer 5 can be improved, and the entire surface of the wafer 5 can be processed uniformly.

  9 and 10 are diagrams for explaining a fifth embodiment of the present invention. In the present embodiment, a disk-shaped excimer lamp 7 is provided instead of the plurality of cylindrical excimer lamps 1 in the third embodiment shown in FIG. 5, and the diameter D of the opening for irradiating vacuum ultraviolet light is set to the wafer diameter. And a wafer stage is fixed.

  FIG. 10 shows an XZ sectional view of the light intensity distribution correction window 8. When the light intensity distribution correction window 8 is not provided, the light intensity distribution in the X-axis direction (radial direction) becomes a light intensity distribution as shown in FIG. 17 according to the distance between the disc-shaped excimer lamp 7 and the wafer 5. However, since the distribution is axisymmetric, the light intensity at the outer peripheral portion is further reduced from that in FIG. The diameter of the disc-shaped excimer lamp was 320 mm.

  In the present embodiment, as in the first embodiment, the intensity distribution of the vacuum ultraviolet light applied to the wafer 5 can be uniformly corrected by changing the plate thickness distribution of the light intensity distribution correction window 8. In the present embodiment, the light intensity distribution correction window has a convex plate thickness distribution as shown in FIG. Further, as described in the first embodiment, the light intensity distribution correction window 8 is designed in consideration of a change in the transmittance of vacuum ultraviolet light due to multiple reflection at the interface, refraction of vacuum ultraviolet light, and the like. Is desirable.

  According to the present embodiment, it is possible to obtain operational effects such as the ability to uniformly treat the entire surface of the wafer 5 as in the third embodiment. Further, the light intensity distribution correction window 8 can be constituted by a simple axisymmetric curved surface as shown in FIG. 10 instead of a wave-shaped complicated curved surface as shown in the third embodiment (FIG. 6). For this reason, it is easy to process and therefore can be manufactured at low cost.

  11 and 12 are diagrams for explaining a sixth embodiment of the present invention. In the present embodiment, a disk-shaped excimer lamp 7 is provided instead of the plurality of cylindrical excimer lamps 1 in the fourth embodiment shown in FIG. 7, and the diameter D of the opening for irradiating vacuum ultraviolet light is made larger than the wafer diameter. The wafer stage is also fixed.

  In FIG. 12, the example of the penetration pattern of the light intensity distribution correction penetration board 9 is shown. The concept of the material and pattern of the light intensity distribution correcting through-hole plate 9 and the distance between the light intensity distribution correcting through-hole plate 9 and the wafer 5 is the same as in the second embodiment (FIG. 4), and detailed description thereof is omitted. In this embodiment, as shown in FIG. 12, a radial and circumferential lattice pattern is used, and the radial direction is a convex light intensity distribution similar to FIG. 10 (however, since it is an axially symmetric distribution, from FIG. Further, the lattice spacing of the circumferential lattice was increased from the central portion toward the outer peripheral portion so as to correct the distribution in which the light intensity at the outer peripheral portion decreased. If the lattice width is constant, and the aperture ratio at the center is unnecessarily lowered, the number of radial lattices is decreased and adjusted. Further, the lattice width may be changed and adjusted to a desired aperture ratio. In this way, by adjusting the aperture ratio of the light intensity distribution correction through-hole plate 9 in the plane, the light intensity distribution of the vacuum ultraviolet light on the wafer 5 becomes a desired distribution (in this case, a uniform distribution). Can be adjusted.

  As described above, also in the sixth embodiment, it is possible to obtain the same functions and effects as those in the fourth embodiment and the fifth embodiment.

  FIG. 13 is a diagram for explaining a seventh embodiment of the present invention. In the present embodiment, a cooling mechanism 10 is provided on the outer peripheral portion of the light intensity distribution correcting through plate 9 in the sixth embodiment shown in FIG.

  As the cooling mechanism 10, an air cooling mechanism using a gas blower or a fan, a water cooling mechanism using cooling water, an electronic cooling mechanism using a Peltier element, or the like can be applied. In the vacuum ultraviolet light processing apparatus, it is desired that the light intensity distribution is made uniform and the light intensity is stabilized.

  One of the factors that cause fluctuations in light intensity is that the vacuum ultraviolet light transmission spectrum changes with the temperature change of the vacuum ultraviolet light transmitting material such as an excimer lamp and a window. For this reason, the light intensity distribution correcting through-hole plate 9 is made of a material having good heat conduction efficiency such as metal or ceramics, and is installed on the window 3 or in the vicinity thereof, and the cooling mechanism 10 is further provided on the outer peripheral portion. As a result, the window 3 is cooled directly by contact heat transfer, and the excimer lamp is indirectly cooled by convection or the like, so that a decrease in light intensity of vacuum ultraviolet light or the like can be suppressed.

  In each of the embodiments described above, the Xe excimer lamp that emits excimer light having a wavelength of 172 nm is used as the cylindrical excimer lamp 1 and the disc-shaped excimer lamp 7. Other vacuum ultraviolet light sources such as an ArF excimer lamp with a wavelength of 193 nm may be used. Further, in each of the above embodiments, the VUV light irradiated to the processing material, such as the light intensity distribution correction window 8 and the light intensity distribution correction penetrating plate 9, is disposed between the light source emitting vacuum ultraviolet light and the processing material. Although means for correcting the in-plane light intensity distribution is provided, it may be used in combination with a reflection mirror that reflects VUV light.

  Further, the vacuum ultraviolet light processing apparatus in each of the embodiments described above removes organic contamination on the wafer, cures the low-k film, reduces the LWR (Line Width Roughness) of the resist pattern, suppresses CD fluctuation of the resist pattern, resist trim ( CD control) and the like.

  In particular, in resist pattern processing, a resist (dry ArF resist, immersion ArF resist, EUV resist, etc.) is exposed with an exposure machine (ArF exposure machine, EUV exposure machine, etc.), developed, and subjected to resist patterning. Thereafter, the vacuum ultraviolet light processing apparatus of the present invention is used to irradiate the vacuum ultraviolet light after the inside of the processing chamber is made a vacuum or an inert gas atmosphere that does not absorb vacuum ultraviolet light such as N2. Thereby, the initial LWR of the resist can be reduced. Further, by using the resist after the LWR is reduced as a mask and etching the resist base film with plasma or the like, it is possible to realize fine processing with a small LWR.

  Similarly, for resist pattern CD fluctuation suppression, shrink exposure (CD reduction) due to electron beam of resist can be suppressed by irradiating vacuum ultraviolet light after resist exposure and development, and stable with CD-SEM etc. Can be measured. Since the dimension of the resist pattern as a mask can be accurately measured in this way, the target CD dimension can be finely processed with high accuracy by etching the base film with plasma or the like.

  In the resist trim, after reducing the pressure of the processing chamber, the reactive gas atmosphere such as O2 or the processing chamber is made an inert gas atmosphere that does not absorb vacuum ultraviolet light such as N2, and then the reactive gas such as O2 is removed. By introducing the resist, the resist can be trimmed and adjusted to a desired CD. Further, depending on the initial CD in-plane distribution or the initial LWR distribution of the resist pattern after lithography, the in-plane distribution of the vacuum ultraviolet light can be changed to a desired distribution (by the light intensity distribution correction window 8 or the light intensity distribution correcting through plate 9). By correcting to a concave distribution, a convex distribution, or the like, the CD in-plane distribution or LWR distribution of the resist pattern can be corrected to a desired distribution such as a highly uniform distribution. In addition, the present invention can be applied to any use for irradiating a processing object such as a wafer with vacuum ultraviolet light.

  As described above, according to the embodiment of the present invention, the in-plane light intensity distribution of the vacuum ultraviolet light irradiated to the material to be processed is corrected between the light source that emits vacuum ultraviolet light and the material to be processed. Means are provided. The means for correcting the in-plane light intensity distribution of the vacuum ultraviolet light is made of a vacuum ultraviolet light transmitting material such as synthetic quartz, MgF2, CaF2, LiF, etc., and the vacuum in order to obtain a desired in-plane light intensity distribution. The thickness of the ultraviolet light transmitting material is changed in the plane. Thereby, the in-plane light intensity distribution of vacuum ultraviolet light can be corrected. The means for correcting the in-plane light intensity distribution of the vacuum ultraviolet light is made of a material that does not transmit vacuum ultraviolet light, such as a metal plate, a ceramic plate, a glass plate, or a Si plate, and has a through mesh structure or a plurality of through hole structures. Thus, the in-plane distribution (aperture ratio) of the penetrating portion is changed so as to obtain a desired in-plane light intensity distribution. Thereby, the in-plane light intensity distribution of vacuum ultraviolet light can be corrected.

  As described above, the light intensity distribution correction window 8 or the light intensity distribution correction through-hole plate 9 is placed between the vacuum ultraviolet light source such as an excimer lamp and the material to be processed such as a wafer, so that the material to be processed is irradiated. Since the light intensity distribution of the vacuum ultraviolet light can be adjusted uniformly, the entire surface of the processing object such as the wafer is irradiated with the vacuum ultraviolet light with high uniformity, and as a result, the wafer 5 can be processed with high uniformity.

DESCRIPTION OF SYMBOLS 1 Cylindrical excimer lamp 2 Lamphouse 3 Window 4 Processing chamber 5 Wafer 6 Wafer stage 7 Disc-shaped excimer lamp 8 Light intensity distribution correction window 9 Light intensity distribution correction penetration board 10 Cooling mechanism

Claims (6)

A light source that emits vacuum ultraviolet light;
A stage for placing the material to be processed;
A correction member that is disposed between the stage and the light source and corrects the in-plane light intensity distribution of the vacuum ultraviolet light applied to the surface of the material to be processed; A vacuum ultraviolet light processing apparatus characterized by irradiating vacuum ultraviolet light having uniform light intensity on a member to be processed. In the vacuum ultraviolet light processing apparatus according to claim 1,
The correction member is made of a vacuum ultraviolet light transmissive material containing any of synthetic quartz, MgF2, CaF2, LiF, and sapphire, and the transmittance in the plane is adjusted by changing the thickness of the transmissive material in the plane. A vacuum ultraviolet light processing apparatus characterized by uniformly correcting the in-plane light intensity distribution of vacuum ultraviolet light. In the vacuum ultraviolet light processing apparatus according to claim 1,
The correction member is made of a vacuum ultraviolet ray non-transmissive material including any one of a metal plate, a ceramic plate, a glass plate, and an Si plate, and has an in-plane transmittance formed by a plurality of through holes formed in the non-transmissive material. A vacuum ultraviolet light processing apparatus characterized in that the in-plane light intensity distribution of vacuum ultraviolet light transmitted through a correction member made of the non-transmissive material material is uniformly corrected. In the vacuum ultraviolet light processing apparatus according to claim 2 or 3,
A vacuum ultraviolet light processing apparatus comprising a cooling mechanism for cooling the correction member. The vacuum ultraviolet light processing apparatus according to claim 4, wherein the cooling mechanism includes any one of an air cooling mechanism, a water cooling mechanism, and a cooling mechanism using a Peltier element. A lamp chamber containing a light source that emits vacuum ultraviolet light;
A processing chamber that houses a stage on which the processing material is placed, irradiates the processing material with vacuum ultraviolet light, and performs a predetermined processing on the processing material;
Gas introduction means for introducing an inert gas into the lamp chamber and the processing chamber;
A correction member that is hermetically disposed at a boundary between the lamp chamber and the processing chamber between the stage and the light source and corrects a light intensity distribution on the processing material of vacuum ultraviolet light irradiated on the processing material; A vacuum ultraviolet light processing apparatus, wherein the processing member is irradiated with vacuum ultraviolet light having uniform light intensity.

Images