JP2004200494A - System and method for removing thin film - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a system and a method for removing thin films in which the quality of thin film removing process can be enhanced while increasing the fabrication yield. <P>SOLUTION: The thin film removing system comprises a wafer stage 1, and a laser irradiation system 2 for irradiating the upper surface (surface) of a wafer W mounted on the wafer stage 1 with a laser beam. The laser irradiation system 2 is provided with a mechanism 30 for regulating the quantity of the laser beam. Thin films, e.g. a resist film and an antireflection film, are removed from the objective region A for removing thin films on the surface of the wafer W by scanning the objective region A with the laser beam of slit shape in the direction of X axis. At first, the objective region A is scanned with a large quantity of the laser beam in order to remove the thin films through the laser ablation phenomenon, and then residues are removed through the laser cleaning phenomenon by scanning the objective region A while lowering the quantity of the beam. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a thin film removing apparatus and a thin film removing method for removing a thin film formed on a surface of a substrate by irradiating the surface of the substrate with laser light. Substrates for thin film removal include, for example, semiconductor wafers, glass substrates for liquid crystal display devices, glass substrates for plasma displays, optical disk substrates, magnetic disk substrates, magneto-optical disk substrates, photomask substrates, etc. It is.
[0002]
[Prior art]
For example, in a manufacturing process of a semiconductor device having a multilayer structure, a photolithography process is repeated, and patterned wiring layers and insulating layers are laminated on a semiconductor wafer (hereinafter simply referred to as “wafer”). In order to make the positional relationship between the layers appropriate, alignment (positioning) of the wafer at the time of exposure processing in the photolithography process is important.
[0003]
The alignment of the wafer is achieved, for example, by detecting an alignment mark formed on the wafer with a CCD camera and adjusting the position of the wafer based on the detection result. However, when a thin film such as a resist film or an antireflection film is formed on the surface of the wafer, the accuracy of alignment mark detection by the CCD camera is lowered, and as a result, the accuracy of wafer alignment is lowered. Therefore, when aligning the wafer, it is necessary to locally remove the thin film on the alignment mark.
[0004]
As a device for removing a thin film on an alignment mark, a thin film removing device using a laser ablation phenomenon has recently attracted attention. In this type of thin film removing apparatus, for example, a certain region on the alignment mark is collectively irradiated with laser light. Then, an ablation phenomenon occurs in which the thin film vaporizes explosively in the region irradiated with the laser light, and as a result, the thin film in the region irradiated with the laser light is removed (see, for example, Patent Document 1).
[0005]
[Patent Document 1]
Japanese Patent Laid-Open No. 10-1173779
[Problems to be solved by the invention]
However, when the thin film is removed by the laser ablation phenomenon, the vaporized material of the thin film scatters from the region where the laser ablation phenomenon occurs (the region irradiated with the laser beam), which becomes particles, which surround the region and alignment. It adheres to the thin film removal target area on the mark.
In order to leave no residue in the thin film removal target area, it is conceivable to irradiate the thin film removal target area multiple times with laser light, but the thin film was removed by repeatedly irradiating with strong laser light. The underlying layer (including the substrate itself) that appears later may be damaged. As a result, there is a problem that the processing quality is deteriorated and the yield of the product is deteriorated.
[0007]
Accordingly, an object of the present invention is to provide a thin film removing apparatus and a thin film removing method capable of improving the quality of thin film removal processing and improving the manufacturing yield.
[0008]
[Means for Solving the Problems and Effects of the Invention]
The invention described in claim 1 for achieving the above object is a thin film removing apparatus for removing a thin film formed on a surface of a substrate (W), wherein the laser irradiates the surface of the substrate with laser light. A light irradiating means (2, 21 to 24), an energy density adjusting means (30) for adjusting the energy density of the laser light irradiated from the laser light irradiating means to the surface of the substrate, the laser light irradiating means and the energy Laser light irradiation control means (5) for irradiating the thin film removal target area (A) on the surface of the substrate with laser light at different energy densities at least twice by controlling the density adjusting means, The light irradiation control means, when irradiating the thin film removal target region at least twice with the laser light, irradiates the laser light after the first time than when irradiating the laser light with the first time. Write time is, so that the energy density of the laser beam irradiated to the thin film removal target area is lowered, a thin film removing apparatus, characterized in that for controlling said energy density adjusting means.
[0009]
In addition, the alphanumeric characters in parentheses represent corresponding components in the embodiments described later. The same applies hereinafter.
The thin film removing method according to claim 2 can be carried out by using the above thin film removing apparatus. That is, the thin film removal method according to claim 2 is a thin film removal method for removing the thin film formed on the surface of the substrate (W) by laser light irradiation, and is a thin film removal target region (A) on the surface of the substrate. ), A first laser light irradiation step (S6) of irradiating a laser beam with a predetermined first energy density, and a predetermined second energy density lower than the first energy density after the first laser light irradiation step. A second laser light irradiation step (S8) for irradiating the thin film removal target region with the laser light.
[0010]
According to the present invention, for example, a laser ablation phenomenon is caused by irradiation with a laser beam having a large energy density to remove a thin film, and then a laser cleaning phenomenon is caused by irradiation with a laser beam having a small energy density. The residue can be removed. Thus, the thin film removal process can be performed without damaging the underlying layer of the thin film to be removed and with little residue. As a result, the quality of the thin film removal process can be improved, and the production yield of products to which the thin film removal process is applied can be improved.
[0011]
According to a third aspect of the present invention, the first energy density is preferably equal to or greater than a threshold value at which a thin film material in a thin film removal target region on the surface of the substrate is removed by a laser ablation phenomenon.
That is, with regard to the thin film removing apparatus, the laser light irradiation control means determines the energy density of the laser light at the time of the first laser light irradiation of the at least two laser light irradiations. It is preferable to control the energy density adjusting means so that the thin film material in the thin film removal target region on the surface has a value equal to or higher than a threshold value removed by the laser ablation phenomenon.
[0012]
According to a fourth aspect of the present invention, the second energy density is preferably a value at which residues on the thin film on the substrate surface are removed by a laser cleaning phenomenon. Furthermore, as described in claim 5, the second energy density is preferably a value that does not damage the underlying layer of the thin film.
That is, with regard to the thin film removal apparatus, the laser light irradiation control means removes the energy density of the laser light during the subsequent laser light irradiation, and the residue on the thin film on the substrate surface is removed by a laser cleaning phenomenon. It is preferable to control the energy density adjusting means so as to be a value (which is further preferably a value that does not damage the underlying layer of the thin film).
[0013]
The laser irradiating means may irradiate the laser beam to the thin film removal target region in a lump, or irradiate the surface of the substrate with a laser beam having a slit shape smaller than the thin film removal target region. Also good. In this case, the slit-shaped laser beam refers to a laser beam that forms a slit-shaped (elongated strip-shaped) laser irradiation region (light image) on the surface of the substrate.
When the slit-shaped laser beam is irradiated, the laser beam from the laser beam irradiation unit is scanned on the surface of the substrate by the scanning unit that relatively moves the laser beam from the laser beam irradiation unit and the substrate. Thus, the entire region of the thin film removal target region can be irradiated with laser light.
[0014]
For example, after the scanning means scans a laser beam having a large energy density in a predetermined direction within a thin film removal target region where the thin film on the surface of the substrate is to be removed, a small energy density is obtained in a direction opposite to that direction. By scanning the laser beam, the first laser light irradiation step and the second laser light irradiation step can be performed. That is, when the thin film removal target region is reciprocally scanned, the thin film can be removed by the laser ablation phenomenon of the thin film material during the forward scan, and the residue can be removed by the laser cleaning phenomenon during the backward scan. Of course, the scanning directions by the laser light at the time of thin film removal and residue removal may coincide.
[0015]
In order to quickly remove particles generated during the thin film removal process due to the laser ablation phenomenon and to suppress overheating of the substrate, a fluid supply means (3) for forming a liquid flow on the substrate surface in the processing target region is provided. It is preferable to provide it.
[0016]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.
FIG. 1 is a diagram conceptually showing the structure of a thin film removing apparatus according to an embodiment of the present invention. For example, this thin film removing apparatus locally removes a thin film such as a resist film or an antireflection film formed on the surface of a wafer W, which is an example of a substrate, prior to an exposure process in a semiconductor manufacturing process. A wafer stage 1 having a substantially horizontal wafer placement surface 11 and a wafer W placed on the wafer placement surface 11 of the wafer stage 1 are used to expose alignment marks provided in the lower layer. And a laser irradiation system 2 for irradiating the upper surface (surface) with laser light.
[0017]
An XY drive mechanism 12 for moving the wafer stage 1 in a horizontal XY plane is coupled to the wafer stage 1. By operating the XY drive mechanism 12 with the wafer W placed on the wafer placement surface 11 of the wafer stage 1, the wafer W placed on the wafer placement surface 11 is moved together with the wafer stage 1 along the XY axis. The irradiation position of the laser beam from the laser irradiation system 2 on the upper surface of the wafer W can be changed by moving the wafer W in the X-Y axis direction.
[0018]
The laser irradiation system 2 includes a laser oscillator 21 that oscillates pulsed laser light, a light amount adjustment mechanism 30 for adjusting the light amount (energy density) of the laser light, and an enlargement optical system 22 that expands the laser light after the light amount adjustment. And a mask 23 for shaping the cross-sectional shape of the laser light magnified by the magnifying optical system 22 into a slit shape (a narrow rectangular shape), and condensing the slit-shaped laser light shaped by the mask 23, A reduction optical system 24 for guiding the surface of the wafer W on the wafer stage 1 is included.
[0019]
The laser oscillator 21 oscillates laser light having a wavelength of 0.4 μm or less (for example, excimer laser light, YAG laser light, etc.). For example, the pulse laser beam from the laser oscillator 21 travels substantially vertically upward, the light amount is adjusted by the light amount adjusting mechanism 30, and then the optical path is bent in a substantially horizontal direction by the reflecting mirror 25, so Incident light is magnified at a predetermined magnification by the magnification optical system 22. The laser beam magnified by the magnifying optical system 22 travels in a substantially horizontal direction, the optical path is bent substantially vertically downward by the reflection mirror 26, and the upper surface of the mask 23 disposed substantially parallel to the wafer W on the wafer stage 1. Is irradiated.
[0020]
A slit 231 is formed on the mask 23 at a position where the laser beam is irradiated (on the optical path of the laser beam), and a part of the laser beam irradiated on the upper surface passes through the slit 231, so that the laser beam is The cross-sectional shape is shaped into a shape corresponding to the slit 231 (slit shape). The laser light shaped into a slit shape by the mask 23 is condensed at a predetermined reduction magnification by a reduction optical system (imaging optical system) 24 and is incident on the upper surface of the wafer W placed on the wafer stage 1. As a result, for example, a laser beam is irradiated onto a slit-shaped region (for example, a region of 3 μm × 85 μm) long in the Y-axis direction on the upper surface of the wafer W. In other words, a slit-shaped optical image (laser image) that is long in the Y-axis direction is formed on the upper surface of the wafer W.
[0021]
Further, a nozzle 3 for supplying water (pure water) to the upper surface of the wafer W is disposed above the wafer stage 1. The water supplied from the nozzle 3 to the upper surface of the wafer W forms, for example, a water flow that flows on the wafer W in the negative direction of the X axis when the right direction in FIG. 1 is the positive direction of the X axis in the horizontal XY plane. To do. At a position away from the wafer placement surface 11 by a predetermined distance, for example, a transparent plate 4 made of quartz is disposed substantially parallel to the wafer placement surface 11. In contact with the water flow (water film) formed above, the height of the water flow is regulated to the interval (the predetermined interval) between the wafer mounting surface 11 and the lower surface of the transparent plate 4. Thereby, a water flow layer having a certain thickness in contact with the lower surface of the transparent plate 4 is formed on the wafer W, and the laser light from the laser irradiation system 2 passes through the transparent plate 4 and the water flow layer and passes through the upper surface of the wafer W. Will be irradiated.
[0022]
The thin film removing apparatus further includes a control device 5 having a configuration including a microcomputer. The control device 5 controls the laser oscillator 21 to irradiate the upper surface of the wafer W with the slit-shaped laser light from the laser irradiation system 2, while controlling the XY drive mechanism 12 so that the wafer W is exposed to the wafer stage 1. Reciprocally move in the X-axis direction. As a result, the slit-shaped laser beam reciprocates (scans) in the X-axis direction on the upper surface of the wafer W. As a result, the rectangular region on the upper surface of the wafer W is irradiated with the laser beam a plurality of times. A thin film such as a resist film or an antireflection film is removed from the rectangular region irradiated with.
[0023]
Further, the control device 5 controls the light amount adjustment mechanism 30 to change the light amount of the laser light irradiated on the wafer W in at least two stages.
2A and 2B are illustrative views showing a configuration example of the light amount adjusting mechanism 30. FIG. The light amount adjusting mechanism 30 shown in FIG. 2A is arranged in order from the laser oscillator 21 side, an electro-optical element EO as polarization state control means interposed on the optical path of the laser light from the laser oscillator 21, and a specific polarization. And a polarizing beam splitter PBS as a pass filter means. The electro-optical element EO can control the birefringence of the material on the optical path by applying an electric field according to a control signal from the control device 5. The polarization beam splitter PBS allows specific polarization to pass and changes the traveling direction of other polarization by 90 degrees. Therefore, by controlling the polarization state of the laser light by controlling the electro-optical element EO, the amount of light that passes through the polarization beam splitter PBS and reaches the magnifying optical system 22 can be adjusted.
[0024]
The light quantity adjusting mechanism 30 shown in FIG. 2 (b) is, in order from the laser oscillator 21 side, a wave plate (λ / 2 plate, as a polarization state control means interposed on the optical path of the laser light from the laser oscillator 21. (λ / 4 plate, etc.) 31 and a polarization beam splitter PBS as a specific polarization pass filter means. Since the polarization state of the laser light that has passed through the polarizing plate 31 is changed by controlling the direction of the wave plate 31 by the control device 5, the amount of light that reaches the magnifying optical system 22 through the polarizing beam splitter PBS is adjusted. it can.
[0025]
2A and 2B, a polarization filter may be used as the specific polarization pass filter means instead of the polarization beam splitter PBS.
2A and 2B, an attenuator incorporated in the laser oscillator 21 may be used as a light amount adjusting mechanism, and the attenuator may be controlled by the control device 5.
FIG. 3 is a diagram for explaining an example of the operation of the thin film removing apparatus, and FIG. 4 is a flowchart for explaining the flow of the thin film removing process. The operation of this thin film removing apparatus will be described by taking as an example the case of removing a thin film from a rectangular thin film removal target area A having a width in the X-axis direction of 160 μm and a width in the Y-axis direction of 85 μm.
[0026]
The wafer W to be subjected to thin film removal is carried in by a robot arm (not shown) and placed on the wafer placement surface 11 of the wafer stage 1 with its surface facing up (step S1). When the wafer W is placed, first, the XY drive mechanism 12 is controlled by the control device 5, and the laser light from the laser irradiation system 2 is on the alignment mark (usually a plurality of laser beams) on the wafer W. The position of the wafer W is adjusted so as to irradiate the irradiation start position A1 that is a predetermined distance D (for example, 5 to 20 μm) away from the end of the thin film removal target area A that is the area of (Step S2).
[0027]
After the position adjustment of the wafer W, the supply of water from the nozzle 3 to the surface of the wafer W is started, and a water flow that flows in the negative direction of the X axis is formed on the wafer W (step S3).
Subsequently, the light amount adjusting mechanism 30 is controlled by the control device 5, whereby the light amount of the laser light applied to the thin film on the wafer W is set to a predetermined first light amount (step S4). The first light quantity is determined so that the energy density of the laser beam on the surface of the wafer W is equal to or higher than a threshold energy density at which the thin film to be removed on the wafer W can be removed by the laser ablation phenomenon. For example, when the thin film to be removed is an antireflection film used in a photolithography process, the threshold energy density is about 0.4 J / cm ² .
[0028]
Next, the laser oscillator 21 is controlled by the control device 5, and the irradiation of the pulse laser beam from the laser irradiation system 2 to the surface of the wafer W is started (step S5). The pulse laser beam is repeatedly oscillated from the laser oscillator 21 at a constant frequency f (for example, 50 Hz). Thereby, for example, a 3 μm × 85 μm slit-shaped pulse laser beam is repeatedly irradiated to a position separated by a predetermined distance D from the end of the thin film removal target area A on the X axis negative direction side. In the region A1 irradiated with the pulse laser beam, a laser ablation phenomenon occurs every time the pulse laser beam is irradiated, and the thin film is removed by this laser ablation phenomenon.
[0029]
When a predetermined number (a predetermined number of pulses) of pulsed laser light is applied to the surface of the wafer W, the control device 5 controls the XY driving mechanism 12 so that the position of the wafer W is the X axis of the slit-shaped pulsed laser light. It is moved in the negative direction of the X axis by a distance equal to the direction width. That is, when the laser irradiation system 2 irradiates the surface of the wafer W with a 3 μm × 85 μm slit-shaped pulsed laser beam, the wafer W is moved by 3 μm in the negative direction of the X axis. As a result, the irradiation region of the pulsed laser light on the surface of the wafer W moves to a region adjacent to the previous laser light irradiation region in the positive direction of the X axis, and the thin film in the new laser light irradiation region is removed. . Thereafter, similarly, every time a predetermined number of pulsed laser beams are irradiated onto the surface of the wafer W, the irradiated region of the pulsed laser beam is moved to a region adjacent in the positive direction of the X axis.
[0030]
When the irradiation area of the pulse laser beam reaches the end on the X-axis positive direction side of the thin film removal target area A, and the area is irradiated with a predetermined number of pulse laser beams, the moving direction of the irradiation area of the pulse laser beam is It can be changed in the opposite direction. That is, the XY drive mechanism 12 is controlled by the control device 5 and the position of the wafer W is moved in the negative direction of the X axis by a distance equal to the width of the slit-shaped pulse laser beam in the X axis direction. The irradiation region of the pulse laser beam on the surface of the laser beam is moved to a region adjacent to the previous laser beam irradiation region in the negative X-axis direction. Thereafter, each time a predetermined number of pulsed laser beams are irradiated onto the surface of the wafer W, the irradiated region of the pulsed laser beam is moved to a region adjacent in the negative X-axis direction.
[0031]
Then, when the irradiation region of the pulse laser beam reaches the end of the thin film removal target region A on the X axis negative direction side and the region is irradiated with a predetermined number of pulse laser beams, the moving direction of the irradiation region of the pulse laser beam Is reversed again. That is, every time a predetermined number of pulsed laser beams are irradiated, the laser beam irradiation region is moved in the positive direction of the X axis and moved to the irradiation start position A1. Thus, the first scan for removing the thin film in the thin film removal target area A by the laser ablation phenomenon is performed (step S6).
[0032]
In this first scan, each portion of the thin film removal target region A receives the predetermined number of pulsed laser beams twice. Therefore, the predetermined number does not damage the underlying layer (may be another thin film layer or the wafer W itself) by two irradiations with the predetermined number of pulsed laser beams. It is determined that a degree of ablation will be performed.
Next, the control device 5 controls the light amount control mechanism 3 to adjust the light amount of the laser light to a second light amount smaller than the first light amount (step S7). This second light quantity is determined so that the energy density of the laser light applied to the surface of the wafer W is less than a threshold value that damages the underlying layer of the thin film to be removed. Specifically, if the base layer is silicon, the energy density threshold value that damages the silicon is about 0.4 J / cm ² . If the underlayer is a TiN layer, the threshold value of the energy density that damages the TiN layer is about 0.1 J / cm ² . In general, if the threshold value of the energy density required for removing the thin film to be removed is higher than the threshold value of the energy density that damages the underlying layer, the thin film is good without damaging the underlying layer. Can be removed.
[0033]
After setting the second light quantity, the thin film removal target area A is reciprocated from the irradiation start position A1 in the same manner as in the first scan, and a predetermined number of parts are applied to each part in the thin film removal target area A. Irradiation with pulsed laser light is performed twice. As a result, a laser cleaning process is performed to remove residues in the thin film removal target area A1 without damaging the underlying layer (step S8).
After the second scan is thus performed, the control device 5 stops the oscillation of the laser oscillator 21 (step S9).
[0034]
In this manner, the thin film is removed from the thin film removal target area A on the surface of the wafer W, and the residue is cleaned. Thereafter, after the supply of water from the nozzle 3 to the wafer W is stopped (step S10), if there is another thin film removal target region on the wafer W (NO in step S11), the other thin film removal target. The process from step S2 is repeated for the area.
When the processing for all the thin film removal target areas on the wafer W is completed (YES in step S11), the processed wafer W is unloaded from the wafer stage 1 by the robot arm (step S12).
[0035]
As described above, according to this embodiment, the thin film removal target region A is reciprocated twice, the thin film is removed by the laser ablation phenomenon at the first scan, and the laser cleaning phenomenon is performed at the second scan. Residue removal processing is performed. Thereby, the thin film can be removed without damaging the underlying layer to be removed, and the residue in the thin film removal target region can be reduced. Therefore, the quality of the thin film removal process is improved, and the manufacturing yield of the semiconductor device can be improved.
[0036]
Furthermore, in this embodiment, the laser beam irradiation start position A1 is set to a position separated by a predetermined distance D from the end of the thin film removal target area A on the X axis negative direction side, and the laser beam is scanned in the X axis negative direction. At this time, the laser beam overruns the irradiation start position A1 and is moved to the end of the thin film removal target area A on the X axis negative direction side. Thus, when the irradiation start position A1 is irradiated with laser light, the particles P concentrate and adhere to the vicinity of the intermediate portion in the longitudinal direction of the slot-shaped laser irradiation area on the X axis negative direction side of the irradiation start position A1. However, the particles P can be removed by a laser ablation phenomenon or a laser cleaning phenomenon.
[0037]
As mentioned above, although one Embodiment of this invention was described, this invention can also be implemented with another form. For example, in the above embodiment, the reciprocating scan of the thin film removal target area A is performed in both the first scan for thin film removal by the laser ablation phenomenon and the second scan for residue removal by the laser cleaning phenomenon. Each part of the thin film removal target area A is irradiated with the pulse laser beam twice. However, for example, during the forward scan in which the thin film removal target area A is irradiated with pulsed laser light from the irradiation start position A1 toward the X axis positive direction end or the negative direction end, the laser Perform a thin film removal process (first scan) using the ablation phenomenon, and perform a scan of the return path that is irradiated with pulsed laser light from the X-axis positive end or negative end to the irradiation start position A1. In some cases, a residue removal process (second scan) using a laser cleaning phenomenon may be performed. Of course, the irradiation start position may be the X axis negative direction side end or the positive direction side end of the thin film removal target area A, instead of the irradiation start position A1 in the X axis intermediate portion.
[0038]
In addition, after the thin film is removed by the laser ablation phenomenon by irradiating the pulse laser beam (first light amount) once or a plurality of times in the slit-shaped region irradiated with the pulse laser beam, the irradiation position of the laser beam is changed. Without changing, the amount of light is reduced to the second amount of light, one or a plurality of times of pulsed laser light is irradiated, residue removal processing by laser cleaning is continued, and then the laser light irradiation position is changed. It may be.
[0039]
Further, the amount of light may be changed in three or more stages. That is, for example, when the same region is irradiated with pulse laser light three times or more, the light amount is gradually decreased from the light amount that can cause the laser ablation phenomenon to the light amount that can cause the laser cleaning phenomenon. You may make it go.
Further, as the mask 23, an aperture having an opening corresponding to the thin film removal target area is used as a diaphragm member, and the thin film removal target laser scanning phenomenon and laser cleaning phenomenon are performed by batch shot without scanning the thin film removal target area. You may make it remove the residue by.
[0040]
In addition, when the wafer W is irradiated with the laser beam, a water flow is formed on the wafer W. However, if the thin film on the surface of the wafer W is not adversely affected, for example, ion water, ozone water, carbonated water, or the like is used. A liquid flow may be formed on the wafer W, or a gas flow such as an inert gas such as nitrogen gas, argon gas, or helium gas may be formed on the wafer W. .
In addition, various design changes can be made within the scope of matters described in the claims.
[Brief description of the drawings]
FIG. 1 is a diagram conceptually showing the structure of a thin film removing apparatus according to an embodiment of the present invention.
FIG. 2 is an illustrative view showing a configuration example of a light amount adjustment mechanism.
FIG. 3 is a diagram for explaining an example of the operation of the thin film removing apparatus.
FIG. 4 is a flowchart for explaining a flow of processing by the thin film removing apparatus.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Wafer stage 2 Laser irradiation system 3 Nozzle 5 Control apparatus 12 XY drive mechanism 21 Laser oscillator 30 Light quantity adjustment mechanism A Thin film removal object area W Wafer

Claims (5)

A thin film removing apparatus for removing a thin film formed on a surface of a substrate,
Laser light irradiation means for irradiating the surface of the substrate with laser light;
Energy density adjusting means for adjusting the energy density of the laser light applied to the surface of the substrate from the laser light irradiation means;
A laser beam irradiation control unit that controls the laser beam irradiation unit and the energy density adjusting unit to irradiate the thin film removal target region on the surface of the substrate with a laser beam at least twice at different energy densities;
When the laser light irradiation control means irradiates the thin film removal target region at least twice with the laser light irradiation, the laser light irradiation control means, when the laser light irradiation is performed later, The thin film removing apparatus characterized in that the energy density adjusting means is controlled so that the energy density of the laser light applied to the thin film removal target region is lowered. A thin film removal method for removing a thin film formed on a surface of a substrate by laser light irradiation,
A first laser light irradiation step of irradiating a thin film removal target region on the surface of the substrate with a laser beam having a predetermined first energy density;
After the first laser light irradiation step, a second laser light irradiation step of irradiating the thin film removal target region with laser light having a predetermined second energy density lower than the first energy density is included. Thin film removal method. 3. The thin film removal method according to claim 2, wherein the first energy density is a value equal to or greater than a threshold value at which a thin film material in a thin film removal target region on the surface of the substrate is removed by a laser ablation phenomenon. 4. The thin film removal method according to claim 2, wherein the second energy density is a value at which residues on the thin film on the substrate surface are removed by a laser cleaning phenomenon. 5. The thin film removal method according to claim 2, wherein the second energy density is a value that does not damage the underlying layer of the thin film.

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