WO2017039184A1

WO2017039184A1 - Adhesive removing device and method

Info

Publication number: WO2017039184A1
Application number: PCT/KR2016/009002
Authority: WO
Inventors: 박일현; 조대엽; 김영중
Original assignee: (주)이오테크닉스
Priority date: 2015-09-04
Filing date: 2016-08-17
Publication date: 2017-03-09

Abstract

A device for removing an adhesive for adhering a mask and a pellicle from the mask is disclosed. The disclosed adhesive removing device comprises: a laser emitting unit for emitting a laser beam at an adhesive layer formed between the mask and the pellicle; a control unit for controlling the wavelength, waveform, and energy density of the laser beam so as to remove the adhesive layer by the emission of the laser beam; and a photographing unit for monitoring a region at which the laser beam is emitted.

Description

Adhesive Removal Apparatus and Method

An apparatus and method for removing adhesive on a mask to separate a pellicle from a mask.

In the lithography process in the manufacture of circuit patterns, such as a semiconductor device or a liquid crystal display, a substrate for exposure, such as a photomask or a reticle, is used. However, when foreign matter such as contaminants adheres to the substrate for exposure, the precision of the lithography process may be reduced. In order to prevent foreign matter adhesion, a dust cover called a pellicle is mounted on the photomask or reticle.

In manufacturing processes, such as a semiconductor device, such as LSI and an ultra-LSI, and a liquid crystal display panel, patterning is performed by irradiating light to a photosensitive layer etc. through a mask (it is also called an exposure disc and a reticle). At this time, if foreign matter is attached to the mask, the light is absorbed or bent by the foreign matter. For this reason, there arises a problem that the pattern to be formed is deformed or the edges are jagged and the dimension, quality and appearance of the patterning are damaged. To alleviate this problem, a dust cover called a pellicle is mounted on the mask.

The pellicle includes a pellicle frame made of metal and a pellicle film disposed on one side of the pellicle frame. And the mask adhesive for fixing a pellicle to a mask may be formed in the surface of the other end of a pellicle frame. The pellicle must be replaced when it reaches its end of life or is damaged. To do this, the adhesive must be removed.

Conventionally, the adhesive is removed by a wet removal method using sulfuric acid or an organic chemical, but in this case, not only the adhesive but also the mask may be damaged together, and the adhesive removal process is very difficult.

According to embodiments, a method and apparatus for separating a pellicle by removing an adhesive formed between a mask and a pellicle using a laser beam is provided.

In one aspect,

In the apparatus for removing from the mask the adhesive for bonding the mask and pellicle,

A laser irradiator for irradiating a laser beam to the adhesive layer formed between the mask and the pellicle; And

A controller for controlling the wavelength, waveform, and energy density of the laser beam such that the adhesive layer is removed by irradiation of the laser beam; And

Provided is an adhesive removal apparatus comprising a; photographing unit for monitoring the area irradiated with the laser beam.

The photographing unit may include an illumination light source for illuminating illumination light and a camera for photographing the illumination light reflected from an area to which the laser beam is irradiated.

The adhesive removing device may include a mirror to which the illumination light and the laser beam are incident and which one of the illumination light and the laser beam transmits and the other reflects.

The wavelength of the illumination light may be configured to be different from the wavelength of the laser beam.

The photographing unit may include an optical filter that transmits light having the same wavelength as the wavelength of the illumination light and shields light having a wavelength different from the wavelength of the illumination light among the light incident on the photographing unit.

The wavelength of the laser beam may be 193nm to 290nm.

The wavelength of the illumination light may be 570nm to 770nm.

The display apparatus may further include an auxiliary photographing unit provided outside the path of the laser beam to photograph the illumination light scattered on the adhesive layer and the mask.

The auxiliary photographing unit may include an optical filter that shields the laser beam and transmits the illumination light, and a camera that photographs the illumination light transmitted through the optical filter.

In another aspect,

In the method of removing from the mask the adhesive for bonding the mask and pellicle,

Controlling the wavelength, waveform and energy density of the laser beam such that the adhesive layer is removed by irradiation of a laser beam;

Irradiating a laser beam on an adhesive layer formed between the mask and the pellicle; And

And obtaining a photographed image of the area to which the laser beam is irradiated.

The adhesive removal method may include changing a region to which the laser beam is irradiated when it is determined that the adhesive layer is removed from the photographed image.

The acquiring of the captured image may include irradiating illumination light to an area to which the laser beam is irradiated and photographing the illumination light reflected from an area to which the laser beam is irradiated.

Acquiring the photographed image,

The laser beam may be provided outside the path of the laser beam, and photographing the illumination light scattered on the adhesive layer and the mask.

The adhesive removal method may include transmitting one of the illumination light and the laser beam and reflecting the other by using a mirror in a path of the laser beam.

The wavelength of the laser beam may be 193nm to 290nm, the wavelength of the illumination light may be configured to be 570nm to 770nm.

According to exemplary embodiments, a laser beam may be used to remove the adhesive layer on the mask. In addition, the adhesive removal process may be monitored by acquiring a photographed image of the laser beam irradiation area. In addition, the time for which the laser beam is irradiated from the monitoring result can be properly adjusted to shorten the adhesive removal time and to ensure the removal of the adhesive layer. In addition, the laser beam can be prevented from being excessively irradiated to damage the mask.

1 is a perspective view showing a state in which a pellicle is attached on a mask.

FIG. 2 is a cross-sectional view of a mask and a pellicle shown in FIG. 1.

3 is a view showing the adhesive remaining on the surface of the mask after removing the pellicle from the mask.

4 is a view schematically showing an adhesive removing device according to an exemplary embodiment.

5 is a diagram illustrating a configuration of a photographing unit.

Fig. 6 is a flowchart showing a method of removing an adhesive using an adhesive removing apparatus according to an exemplary embodiment.

7 is a diagram illustrating a photographed image acquired by a photographing unit by way of example.

8 is a diagram illustrating another example of a captured image acquired by the photographing unit.

Hereinafter, a mirror mount for a laser processing apparatus according to an exemplary embodiment will be described in detail with reference to the accompanying drawings.

In the drawings, like reference numerals refer to like elements, and the size of each element in the drawings may be exaggerated for clarity and convenience of description. Meanwhile, the embodiments described below are merely exemplary, and various modifications are possible from these embodiments.

* Hereinafter, what is described as "top" or "upper" may include not only directly above and in contact but also above noncontact.

Terms such as first and second may be used to describe various components, but the components should not be limited by the terms. The terms are only used to distinguish one component from another.

Singular expressions include plural expressions unless the context clearly indicates otherwise. In addition, when a part is said to "include" a certain component, which means that it may further include other components, except to exclude other components unless otherwise stated.

In addition, terms such as “unit” and “module” described in the specification mean a unit that processes at least one function or operation.

1 is a perspective view illustrating a state in which a pellicle 20 is attached on a mask 10. 2 is sectional drawing which showed the cross section of the mask 10 and the pellicle 20 shown in FIG.

1 and 2, the pellicle 20 may be attached to the mask 10. The mask pattern 12 may be formed on the mask 10. The shape of the mask pattern 12 may vary depending on a patterning shape to be formed through a lithography process in a semiconductor device such as an LSI, an ultra LSI, or a liquid crystal panel. The mask 10 may include various materials. In exemplary embodiments, the mask 10 may include quartz. In addition, the mask 10 may include a quartz layer and a chromium (Cr) layer provided on the quartz layer. As another example, the mask 10 may include a quartz layer and a molybdenum silicide (MoSi) layer provided on the quartz layer. Accordingly, the mask 10 may include at least one of quartz, chromium, and molybdenum silicide on the surface that meets the adhesive 30. The above materials are merely exemplary and are not limited thereto.

The pellicle 20 may be attached to the mask 10. The pellicle 20 may include a pellicle frame 24 and a pellicle film 22 provided on the pellicle frame 24. The size and shape of the pellicle frame 24 may vary depending on the size and shape of the mask 10 used in the lithographic process. In addition, the size and shape of the pellicle frame 24 may not necessarily correspond to the size and shape of the mask 10. The pellicle film 22 may be attached to one surface of the pellicle frame 24. The pellicle film 22 may be attached through the pellicle frame 24 and the pellicle adhesive layer 26. However, the present invention is not limited thereto, and the pellicle film 22 and the pellicle frame 24 may be integrally connected without the pellicle adhesive layer 26. The pellicle film 22 is a transparent material and may transmit light through the pellicle film 22 during the lithography process. The light transmitted through the pellicle film 22 can pattern the object to be processed via the mask 10.

When the pellicle 20 is attached on the mask 10, a predetermined space may be provided between the pellicle film 22 and the mask 10. The predetermined space may be blocked from the outside by the pellicle film 22 and the pellicle frame 24. Therefore, foreign matters may be prevented from entering the mask 10.

The pellicle 20 may be attached to the mask 10 through the adhesive 30. The adhesive 30 may be formed of an adhesive having adhesive strength, and the pellicle 20 may be fixed on the mask 10. In exemplary embodiments, the adhesive 30 may include a fluoropolymer-based material. Exemplary of the fluoropolymer series materials include polytetrafluoroethylene polymer, tetrafluoroethylene (TFE) / perfluoro (alkyl vinyl ether) polymer and ethylene / tetrafluoroethylene polymer, chlorotrifluoroethylene (CTFE) And the like, but are not limited thereto. In addition to the fluoropolymer series, the adhesive 30 may include other materials. For example, the adhesive 30 may include a hydrogenated substance of a block polymer having a saturated cyclic hydrocarbon structure such as styrene / isoprene / styrene-based triblock polymer, and an adhesive material containing a tackifier. It may also comprise a hot melt adhesive material containing styrene / ethylene / propylene / styrene triblock copolymers and aliphatic petroleum resins.

3 is a view showing a state in which the adhesive 30 remains on the surface of the mask 10 after removing the pellicle 20 from the mask 10.

As shown in FIG. 3, if the adhesive 30 remains on the mask 10, it may be difficult to replace the pellicle 20 and attach it to the mask 10 again. Conventionally, an organic compound or a sulfuric acid compound was used to remove the adhesive on the mask 10. That is, the adhesive 30 may be removed through a wet cleaning process using the organic compound or the sulfuric acid compound. However, when the wet cleaning process is performed, a problem may occur in that the transmittance of the mask pattern 12 or the material of the mask 10 of the mask 10 is changed. In addition, the cleaning process itself is cumbersome and time consuming.

Referring to FIG. 4, the adhesive layer 30 is removed by irradiation of a laser beam 110 and a laser beam to irradiate a laser beam to the adhesive layer 30 formed between the mask 10 and the pellicle 20. The controller 120 may control the wavelength, the waveform, and the energy density of the laser beam. In addition, the adhesive remover may further include a laser measuring unit 115 to provide feedback information on the parameters of the laser beam.

Most of the laser beam emitted from the laser irradiator 110 may be irradiated toward the adhesive layer 30 on the mask 10. A part of the laser beam may be incident to the laser measuring unit 115. The laser measuring unit 115 may measure the wavelength, waveform, energy density, etc. of the incident laser beam. The laser measuring unit 115 may transmit parameter information of the measured laser beam to the control unit 120. The controller 120 may determine the control information of the parameter of the laser beam based on the measurement information of the laser measuring unit 115. The controller 120 may transmit the control information to the laser irradiation unit 110.

When controlling the wavelength of the laser beam, the controller 120 may allow the photons of the laser beam to have energy enough to separate the bonding structure of the adhesive layer 30. For example, as described above, when the adhesive layer 30 includes a fluoropolymer-based material, energy of 4.5 eV or more may be required to separate the bonding structure of the fluorine-based material. Therefore, the control part 120 can control the wavelength of a laser beam to 266 nm or less. The above figures are exemplary only and are not limited thereto. The wavelength of the laser beam may vary depending on the bonding structure of the materials the adhesive layer 30 may have. However, if the wavelength of the laser beam is too short, it may damage the mask (10). Therefore, the wavelength of the laser beam can be adjusted in the range of approximately 193 nm to 290 nm.

In addition, the controller 120 may adjust the waveform of the laser beam into a pulse waveform that is repeated at a constant cycle. In this case, the laser beam may have a pulse waveform having a predetermined pulse width and period. The reason for adjusting the waveform of the laser beam is as follows. If the waveform of the laser beam is not a pulse waveform but a waveform having a constant energy intensity, the temperature of the adhesive layer 30 may continue to rise while irradiating the laser beam. However, the temperature at which the mask 10 can withstand damage is limited. For example, in order for the properties of the mask 10 not to change, the temperature of the mask 10 should be maintained at about 200 ° C or less. Therefore, when irradiating the laser beam to the adhesive layer 30, it is necessary to maintain the temperature of the adhesive layer 30 so as not to be higher than the temperature at which the characteristics of the mask 10 changes. To this end, the laser beam may have a pulse waveform that is repeated at a predetermined cycle. If the laser beam has a pulse waveform, the adhesive layer 30 increases in temperature while the energy of the laser beam is high, and the adhesive layer 30 is lowered again while the energy of the laser beam is low. It is possible to prevent the temperature of the layer 30 from monotonically increasing.

For example, the controller 120 may adjust the pulse width of the laser beam in a range of about 10ps to 100ns. In addition, the control unit 120 may have a period of the pulse wave of 10Hz to 100Hz. In an exemplary embodiment, as the pulse width increases in the above range, the period may also increase, but is not necessarily limited thereto.

In addition, the controller 120 may adjust the energy density of the laser beam in the range of 25 mJ / cm 2 to 1000 mJ / cm 2.

Adhesive removal apparatus according to the embodiment may include a photographing unit 130 for monitoring the area to which the laser beam is irradiated. The photographing unit 130 may provide photographing information of a region to which the laser beam is irradiated. Through this, the photographing unit 130 may provide monitoring information on the removal of the adhesive layer 30. The mirror 140 may be provided in front of the photographing unit 130. The mirror 140 may transmit the laser beam. On the other hand, the mirror may reflect the illumination light (L2) from the photographing unit 130 to be described later.

5 is a diagram illustrating a configuration of the photographing unit 130.

Referring to FIG. 5, the photographing unit 130 may include an illumination light source 132. The illumination light source 132 may irradiate the illumination light L2 necessary for photographing the laser beam irradiation area. As described above, the processing laser beam may be short in wavelength and suitable for destructive processes. Therefore, direct imaging of the processing laser beam may cause damage to the apparatus, and may also degrade the quality of the photographed image. Therefore, the photographing unit 130 may obtain the photographed image of the laser beam irradiation area by using the illumination light L2 emitted from the illumination light L2. Here, the captured image is a concept including not only real time image information but also still image information.

The photographing unit 130 may include a camera 138 for photographing the illumination light L2. The wavelength of the illumination light L2 may be adjusted to the visible light region so that the camera 138 easily acquires the captured image. For example, the wavelength of the illumination light L2 may be 570 nm to 770 nm.

The photographing unit 130 may include a beam splitter 134 for transmitting some of the light emitted from the illumination light source 132 and reflecting some of the illumination light reflected from the laser beam irradiation area toward the camera 138. The illumination light L2 reflected by the beam splitter 134 may be incident on the camera 138. The camera 138 may receive the illumination light L2 to obtain a captured image of the laser beam irradiation area.

The photographing unit may include an optical filter 136 that transmits light having the same wavelength as the wavelength of the illumination light and shields light having a wavelength different from the wavelength of the illumination light among the light incident on the photographing unit. The optical filter 136 may selectively shield or transmit light depending on the wavelength. The optical filter 136 may shield the laser beam L1 and transmit only the illumination light L2 toward the camera 138. The optical filter 136 may be used to prevent the laser beam from entering the camera 138 and damaging the camera 138.

Referring back to FIG. 4, the adhesive remover may include a mirror 140 to which the illumination light L2 and the laser beam L1 are incident. The mirror 140 may transmit one of the illumination light L2 and the laser beam L1 and reflect the other. For example, the mirror 140 may be a dichroic mirror that selectively reflects or transmits light depending on the wavelength. The wavelength of the laser beam L1 and the illumination light L2 may be set differently. The dichroic mirror may transmit one of the laser beam L1 and the illumination light L2 having different wavelengths and reflect the other.

4 shows an example in which the mirror 140 transmits the laser beam L1 and reflects the illumination light L2. However, the embodiment is not limited thereto. For example, the mirror 140 may reflect the laser beam L1 and transmit the illumination light L2.

4 and 5, the adhesive removing apparatus may further include an auxiliary photographing unit 150 provided outside the path of the laser beam. The auxiliary photographing unit 150 may photograph the illumination light L2 scattered from the laser beam irradiation area. The auxiliary photographing unit 150 may include a camera 152 that photographs the illumination light L2. The auxiliary photographing unit 150 may include an optical filter 154. The optical filter 154 may selectively transmit the light according to the wavelength of the light. For example, the optical filter 154 may shield the laser beam L1 having a wavelength of 193 nm to 290 nm and transmit illumination light having a wavelength of 570 nm to 770 nm. The optical filter 154 may prevent the camera 152 of the auxiliary photographing unit 150 from being damaged by the laser beam L1. Also, the light filter 154 may increase the sharpness of the image of the illumination light L2 captured by the camera 152.

Referring to FIG. 6, the adhesive removal method according to the embodiment includes controlling the wavelength, waveform, and energy density of the laser beam such that the adhesive layer 30 is removed by irradiation of the laser beam L1 (S110). , Irradiating the laser beam L1 to the adhesive layer 30 formed between the mask 10 and the pellicle 20 (S120) and acquiring a photographed image of an area to which the laser beam is irradiated (S130). can do.

In operation S110, the controller 120 may adjust parameters of the laser beam. For example, the controller 120 may adjust the wavelength of the laser beam L1 to approximately 193 nm to 290 nm. In addition, the controller 120 may adjust the pulse width of the laser beam L1 in a range of approximately 10 ps to 100 ns, and a period of the pulse wave in a period of 10 Hz to 100 Hz. The controller 120 may allow the adhesive layer 30 to be removed by the laser beam L1 while reducing damage to the mask 10 by adjusting the parameters of the laser beam L1.

In step S120, the laser beam L1 emitted from the laser irradiator 110 may be irradiated onto the adhesive layer 30.

In operation S130, the capturing unit 130 and the auxiliary capturing unit 150 may acquire a captured image of a region to which the laser beam L1 is irradiated. In order to acquire a captured image, the photographing unit 130 may irradiate the laser beam irradiation area with the illumination light L2 from the illumination light source 132. For example, the wavelength of the illumination light L2 may be 570 nm to 770 nm. The photographed image acquired by the photographing unit 130 may be used to determine whether to change the laser beam irradiation area.

For example, the adhesive removal method may include checking whether the adhesive layer 30 is removed from the photographed image obtained in step S130 (S140) and changing the laser beam irradiation area when the adhesive layer 30 is removed. It may further comprise the step (S150).

In operation S140, it may be determined whether the adhesive layer 30 is removed from the photographed image. In the photographed image, it may be confirmed whether an image from which the adhesive layer 30 is removed is visible. The verification operation may manually determine a photographed image by hand and determine whether to change the laser beam irradiation area therefrom. As another example, the checking operation may be performed by a computing device embedded in the photographing unit 130. The computing device may analyze the captured image by a designated algorithm. For example, the computing device may store an image of the mask 10 surface from which the adhesive has been removed as a reference image. In addition, the computing device may compare the photographed image with the reference image to evaluate the similarity of the two images. The computing device may determine whether to further irradiate the laser beam L1 from the evaluation information on the similarity. For example, when the evaluation information on the similarity is converted into a score, the computing device may determine that the adhesive layer 30 is removed when the score is equal to or greater than a predetermined reference value.

7 is a diagram illustrating a photographed image obtained by the photographing unit 130 by way of example.

Referring to FIG. 7, it can be seen that the adhesive layer 30 remains in the laser beam irradiation area S1 without being completely removed. As shown in FIG. 7, if the adhesive layer 30 remains in the laser beam irradiation area S1 in the photographed image, the process may return to step S120 again to further irradiate the laser beam L1.

8 is a diagram illustrating another example of a captured image acquired by the photographing unit 130.

Referring to FIG. 8, it can be seen that the adhesive layer 30 is removed from the laser beam irradiation area S1 and the surface of the mask 10 is exposed. As shown in FIG. 8, if the adhesive layer 30 does not remain in the laser beam irradiation area S1 in the captured image, step S150 may be performed to change the laser beam irradiation area S1. In operation S150, when the laser beam irradiation area S1 is changed, the irradiation direction of the laser beam L1 of the laser irradiation unit 110 may be changed. As another example, the direction in which the laser beam L1 is irradiated may be changed by adjusting the direction of the scanner without changing the direction in which the laser irradiator 110 irradiates the laser beam L1. As another example, the position at which the laser beam L1 is irradiated does not change, and the mask 10 may be moved by the movement of the workpiece stage (not shown). While moving the mask 10 relative to the position at which the laser beam L1 is irradiated, the position S1 at which the laser beam is irradiated on the mask 10 and the adhesive layer 30 may be changed.

In the above, with reference to FIGS. 1 to 8, the adhesive removal apparatus and the method according to the exemplary embodiments have been described. According to the embodiments described above, the adhesive layer 30 on the mask 10 may be removed using the laser beam L1. In addition, the adhesive removal process may be monitored by acquiring a photographed image of the laser beam irradiation area. In addition, the time for which the laser beam L1 is irradiated from the monitoring result can be appropriately adjusted to shorten the adhesive removal time and ensure the removal of the adhesive layer 30. In addition, it is possible to prevent the laser beam L1 from being excessively irradiated and damaging the mask 10.

While many details are set forth in the foregoing description, they should be construed as illustrative of preferred embodiments rather than to limit the scope of the invention. Therefore, the scope of the present invention should not be defined by the described embodiments, but should be determined by the technical spirit described in the claims.

Claims

In the apparatus for removing from the mask the adhesive for bonding the mask and pellicle,

A laser irradiator for irradiating a laser beam to the adhesive layer formed between the mask and the pellicle;

A controller for controlling the wavelength, waveform, and energy density of the laser beam such that the adhesive layer is removed by irradiation of the laser beam; And

And a photographing unit configured to monitor an area to which the laser beam is irradiated.
The method of claim 1,

The photographing unit includes an illumination light source for illuminating illumination light and a camera for photographing the illumination light reflected from the area irradiated with the laser beam.
The method of claim 2,

And a mirror configured to receive the illumination light and the laser beam and to transmit one of the illumination light and the laser beam and reflect the other.
The method of claim 2,

And the wavelength of the illumination light is different from the wavelength of the laser beam.
The method of claim 2,

The photographing unit includes an optical filter including a light filter for transmitting the light having the same wavelength as the wavelength of the illumination light of the light incident to the photographing unit and shielding the light having a wavelength different from the wavelength of the illumination light.
The method of claim 1,

The wavelength of the laser beam is 193nm to 290nm adhesive removal apparatus.
The method of claim 2,

The wavelength of the illumination light is 570nm to 770nm adhesive remover.
The method of claim 2,

And an auxiliary photographing unit provided outside the path of the laser beam to photograph the illumination light scattered on the adhesive layer and the mask.
The method of claim 8,

The auxiliary photographing unit includes an optical filter for shielding the laser beam and transmitting the illumination light and a camera for photographing the illumination light passing through the optical filter.
In the method of removing from the mask the adhesive for bonding the mask and pellicle,

Controlling the wavelength, waveform and energy density of the laser beam such that the adhesive layer is removed by irradiation of a laser beam;

Irradiating a laser beam on an adhesive layer formed between the mask and the pellicle; And

And obtaining a photographed image of a region to which the laser beam is irradiated.
The method of claim 10,

And when the adhesive layer is found to be removed from the photographed image, changing an area to which the laser beam is irradiated.
The method of claim 10,

The acquiring of the photographed image may include irradiating illumination light to an area to which the laser beam is irradiated and photographing the illumination light reflected from an area to which the laser beam is irradiated.
The method of claim 12,

And the wavelength of the illumination light is different from the wavelength of the laser beam.
The method of claim 12,

Acquiring the photographed image,

And a step of photographing the illumination light scattered on the adhesive layer and the mask provided outside the path of the laser beam.
The method of claim 12,

And transmitting one of the illumination light and the laser beam and reflecting the other by using a mirror in a path of the laser beam.
The method of claim 13,

The wavelength of the laser beam is 193nm to 290nm, the wavelength of the illumination light is configured to be 570nm to 770nm.