JP2003140322A - Reticle cleaning device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a reticle cleaning device which does not require a costly device for a reticle having a foreign matter deposited and efficiently removes the foreign matter. SOLUTION: When the reticle 12 is conveyed from a charging port 16 of a housing 11 into the housing 11 via a conveyance arm 13, an air nozzle 14 which is positioned over a width broader than the width of the reticle 12 is disposed in the housing 11, nitrogen is blown against the reticle which is conveyed at a constant speed thereinto from above and below, thereby, the foreign matter deposited to the reticle 12 is removed over the whole surface of the reticle. The length and angle of the air nozzle 14 with respect to the reticle and the discharge pressure of nitrogen injected from the air nozzle is set so as to be the optimum amount.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a reticle cleaning device, and more particularly, to a reticle cleaning device for removing foreign matters attached to a pellicle film of a reticle having a pellicle film as a protective film by air blow.

[0002]

2. Description of the Related Art A conventional method for cleaning a reticle is shown in FIG.

In the conventional reticle cleaning apparatus, when dust adheres to the pellicle surface, an operator uses the air gun 21 to cause the pellicle film 12d of the reticle substrate and the reticle substrate 1 to be removed.
N ₂ was blown on the back surface of 2a to blow off dust. However, in this method, N sprayed on the pellicle film
The wind pressure of ₂ was too strong, or the tip of the air gun 21 contacted the pellicle film 12d, and the pellicle film was damaged at a frequency of about twice / year.

When the angle of the air gun with respect to the pellicle surface of the pellicle film 12 becomes 60 ° or more, or when the distance between the pellicle surface and the tip of the air gun becomes narrower than 10 mm, the wind pressure blown to the pellicle surface is shown in FIG. It becomes stronger than the proper wind pressure range, increasing the risk of damaging the pellicle membrane.

Further, even when the discharge pressure of N ₂ per one outlet of the air gun 21 becomes 0.7 kgf / cm ² or more, the wind pressure on the pellicle surface also becomes strong and the pellicle film may be damaged. Becomes higher. Sometimes air gun 21
The tip of the pellicle may come into contact with the pellicle membrane and damage the pellicle membrane.

On the contrary, the angle of the air gun to the pellicle surface is 30 ° or less, the distance from the pellicle surface is 15 mm or more, N
_When the discharge pressure of ₂ is 0.3 kgf / cm ² or less, the wind pressure blown to the pellicle surface falls within the appropriate wind pressure range, and dust cannot be completely removed and remains.

Therefore, in order to suppress the wind pressure blown to the pellicle surface within the proper wind pressure range, the angle of the air gun with respect to the pellicle surface is 30 to 60 °, and the distance from the pellicle surface is 1 °.
It is necessary to perform the cleaning operation at 0 to 15 mm and the discharge pressure of N ₂ per one blowout port of 0.3 to 0.7 kgf / cm ² .

In the conventional manual work, it is difficult to maintain such an angle and interval within an appropriate range, and sometimes the pellicle membrane is damaged due to too sharp an angle or too narrow an interval. Will be invited.

Therefore, there is a need for a device that can fix the angle of the air nozzle and the distance between the pellicle surface and the pellicle surface within the above ranges so that the reticle with a pellicle can always be cleaned within an appropriate wind pressure range.

If the pellicle film is damaged, the reticle maker will be asked to replace the pellicle film, but the cost is high (over 200,000 yen per sheet) and the construction period is long. In many cases, the same damaged reticle will be purchased again. 2 for new reticles
The cost is about 0,000 yen / sheet, and the damage occurs about twice / year, resulting in a wasteful expense of about 400,000 yen / year.

If the worker notices the damage of the pellicle film, the cost is about this amount, but if the worker does not notice the damage of the pellicle film and continues to use the reticle, the problem becomes more serious.

If the degree of breakage of the pellicle film is large, the operator will notice it and stop using the reticle. However, the degree of breakage is very small, or the broken point is the metal frame 12.
If it is near the upper part of c, it may not be detected by the dust inspection, and it may be overlooked that it is damaged. In the reticle with the pellicle film 12d damaged in such a state, dust enters from the damaged portion in the subsequent use and adheres to the surface of the chrome pattern 12b.

When dust adheres to the chrome pattern 12b, the dust is transferred onto the semiconductor substrate during the exposure operation using the reticle, which leads to a short circuit of the wiring pattern. As a result, the yield of a semiconductor device manufactured using the semiconductor substrate is reduced. In this way, in step-and-repeat exposure, dust on the reticle
The reticle is repeatedly transferred to the chips that are formed on the semiconductor substrate that is used for the exposure work, and defects are transferred to all the chips in common, so the damage is large, sometimes tens of millions of yen to hundreds of millions of yen. May lead to damage.

For reference, cleaning of a reticle without a pellicle does not use a method of blowing dust off with an air gun. Instead, a reticle cleaning device is used to clean the reticle in pure water with CO ₂ bubbling, and to remove IPA (iso-propyl). -Alcohol) is replaced and dried.

Next, an example in which an air blow method is used as a method for cleaning a reticle with a pellicle film will be described with reference to FIG. Japanese Unexamined Patent Publication No. 2000-98589 shows an example of a device for removing a foreign substance 117 in a reticle foreign substance inspecting device for the purpose of eliminating the human intervention for removing the foreign substance on the reticle. This is one in which the reticle 112 stored in the reticle case 103 is transferred to the transfer arm 11
The foreign matter 102 adhering to the surface of the reticle 112 is detected by using the laser light source 107 and the scattered light detector 108. To remove the detected foreign object 117, and transferring the reticle 112 in reticle stage 106b of the housing 131 to move to the vicinity N ₂ injection nozzle 114 by the transfer arm 113, N ₂ injection nozzle 11
The foreign matter is removed by spraying N ₂ pressurized from No. 4, and the foreign matter is discharged from the discharge port 115.

[0016]

However, in this case, the N ₂ injection nozzle 114 is provided only at one position at the front surface of the reticle 112 and at one position at the back surface thereof, that is, at two positions in total. Therefore, in order to bring the portion where the foreign matter 117 detected by the foreign matter inspection is attached to the vicinity of the nozzle, the transport arm 113 is not limited to the depth direction (X direction) in the foreign matter removing unit but also to the left and right direction (Y direction). ), That is, in two dimensions. For this reason, the transport mechanism needs to move in the XY directions, and the device has a complicated structure, which makes the device expensive. Also,
Since the reticle is moved in the X-Y directions, the foreign matter removing unit becomes large and the area occupied by the apparatus becomes large accordingly.

Further, when a plurality of foreign matters are adhered on the reticle, it is necessary to repeat the procedure of moving the plurality of foreign matter adhering points to the vicinity of the nozzle, removing dust, and moving to the next adhering point. is there. For example, if there are ten foreign matter adhered portions, it is necessary to repeat the movement in the XY directions and the N ₂ injection 10 times, which is a very inefficient work.

An object of the present invention is to provide a reticle cleaning device which can remove foreign matter efficiently without requiring an expensive device for a reticle to which foreign matter is attached.

[0019]

A reticle cleaning device of the present invention includes a housing, a carrying device for carrying a reticle into the housing, and a gas in the reticle carried into the housing in the housing. A reticle cleaning device that has a gas spraying device that sprays a gas and an exhaust port that is attached to the periphery of the housing, and that removes foreign matter adhering to the reticle by injecting gas using the gas spraying device. The gas spraying device has a plurality of gas spraying ports arranged in a range including at least one side of the reticle. The reticle cleaning device of the present invention has the following suitable application modes.

First, in the reticle cleaning apparatus of the present invention, the step of injecting gas using the gas spraying device to remove foreign matter adhering to the reticle is carried out by the carrier device at a predetermined speed. It is carried out by carrying the film into the housing, and scanning the inside of the housing while the reticle receives the air blow on the entire surface of the reticle by the carrying device.

Next, in the reticle cleaning device of the present invention, the gas blowing device has the gas blowing ports on both sides of the reticle.

Next, in the reticle cleaning apparatus of the present invention, the gas blowing port is an air nozzle, and the air nozzle has a space of 10 from the surface of the reticle.
˜15 mm, the angle of the air nozzle with respect to the surface of the reticle is set to 30 to 60 °, and the discharge pressure of the gas injected from the air nozzle is 0.3 to 0.7 kgf /
It is set to cm ² .

Next, in the reticle cleaning device of the present invention, the reticle protects the glass substrate, the light shielding film pattern formed on one surface of the glass substrate, and the light shielding film pattern so as to cover the light shielding film pattern. The reticle cleaning device according to claim 1, further comprising a pellicle film that constitutes one surface of the reticle.

Next, in the reticle cleaning apparatus of the present invention, the gas blowing port is arranged in parallel with at least one side of the reticle.

[0025]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention relates to a device for removing dust adhering to the pellicle surface of a reticle with a pellicle used in an exposure process in a semiconductor manufacturing process, and efficiently without damaging the pellicle film. The purpose is to remove dust.

A reticle cleaning device according to the present invention supports a housing that constitutes the device, a transfer arm that supports the reticle, and an N for efficiently removing dust adhering to the transfer arm, the pellicle surface, and the reticle back surface.
_{2 It is} composed of an air nozzle that has a plurality of (nitrogen) blowout ports arranged in a horizontal row, and an exhaust port for exhausting dust inside the housing to the outside of the housing.

Since the angle and interval of the air nozzles are fixed at optimum values, as in the conventional case where an operator manually carries out cleaning work using an air gun,
It is possible to prevent that the wind pressure on the pellicle surface is too strong, the pellicle film is damaged by the contact of the tip of the air gun, and conversely, the wind pressure is too weak and dust remains without being removed.

As described above, the cleaning apparatus according to the present invention is intended to efficiently remove dust adhering to the pellicle surface or the reticle back surface without damaging the pellicle film.

FIG. 1 is a side view of the reticle cleaning apparatus according to the present invention before the reticle is loaded into the housing, and FIG. 2 is a side view of the apparatus when the reticle is loaded into the housing. A top view corresponding to FIG. 2 is shown in FIG. Further, FIG. 4 is a diagram showing the relationship between the wind pressure of nitrogen (N ₂ ) sprayed on the pellicle surface and the dust removal rate, and the relationship between the pellicle film damage rate.

The reticle cleaning apparatus according to the present invention adheres to the housing 11 and the reticle 12 that constitute the apparatus, the transfer arm 13 for loading and unloading the housing, the pellicle surface of the pellicle film 12d and the back surface of the reticle substrate 12a. An air nozzle 14 that blows out N ₂ (nitrogen) for efficiently removing dust, an exhaust port 15 for exhausting dust in the housing to the outside of the housing, and the reticle 1.
It is composed of two insertion ports 16.

The plurality of air nozzles 14 are arranged side by side in a row, and are wider than the lateral width of the reticle by about 1 to 2 cm as a whole, and N ₂ can be sprayed on the entire area of the reticle 12 in the lateral direction. In addition, the transfer arm 13 is set to 10 to 5
By pulling out at a constant speed of 0 cm / min, N ₂ can be sprayed on the entire area of the reticle in the vertical direction.
With this structure, the dust on the entire surface of both the pellicle surface and the back surface of the reticle 12 can be removed.

The tip of the air nozzle 14 and the pellicle film 12d
Is 10 to 15 mm, and the nozzle angle θ is 30 to 6
It is fixed at 0 °. Further, the discharge pressure of N ₂ per one outlet of the air nozzle 14 is 0.3 to 0.7 kgf.
/ Is fixed in cm ^2, since the wind pressure on the pellicle surface is to fit within the appropriate wind pressure range of 4, breakage of the pellicle film 12d is close to 0 as possible, sufficient to remove dust It is possible to blow N ₂ with a certain wind pressure. Further, as long as there is no abnormality in the transport system, the tip of the nozzle does not come into contact with the pellicle film 12d and the pellicle film 12d is not damaged.

Now, the role of the pellicle film during exposure will be described. FIG. 5 shows how the image formation points differ depending on the presence or absence of the pellicle.

The reticle 12 is formed of a glass substrate 12a having a thickness of about 45 mm, a wiring pattern 12b is formed of chrome on one surface of the reticle 12, and a metal frame 12c is attached to the chrome pattern surface, and nitrocellulose or the like is formed thereon. Pellicle film 12 with a thickness of several tens of microns
d is arranged so as to cover the wiring pattern. The pellicle film 12d and the pattern surface are kept at a distance of several mm by a metal frame 12c. By thus covering the wiring pattern with the pellicle film 12d, it is possible to prevent dust from directly adhering to the wiring pattern of the reticle 12.

The left side of FIG. 5 shows an image forming point in the case of a reticle without a pellicle film. When the foreign matter 17 adheres to the reticle 12 on which the wiring pattern is formed, an image forming point 19 having a pattern of dust is transferred onto the semiconductor substrate 20 via the lens 18. Therefore, a short circuit due to dust in the wiring pattern transferred onto the semiconductor substrate 20 occurs.
The yield of semiconductor devices manufactured using this semiconductor substrate 20 is reduced.

The right side of FIG. 5 shows an image forming point with a pellicle. In this case, the wiring pattern of the reticle is entirely covered with the pellicle film 12d, and dust adheres to the pellicle film 12d. Therefore, the image formation point 1 at the time of exposure
Since 9 is formed at a position beyond the semiconductor substrate 20, no image is formed on the surface of the semiconductor substrate 20. Therefore, the influence of dust can be reduced and the yield as a semiconductor device can be improved.

Similarly, the reticle substrate 12a is thickened to about 45 mm so that dust attached to the back surface of the reticle is not imaged on the semiconductor substrate. (The thickness of the conventional reticle is as thin as about 22.5 mm, and dust adhering to the back surface of the reticle affects wiring shorts in some cases.) However, dust adhering to the pellicle film 12 d also depends on the size. It leads to a short circuit of the wiring pattern. If the size of the dust adhering to the pellicle 12 is about several tens to several hundreds of μm, no image is formed on the semiconductor substrate 20 according to the above theory, which does not lead to a short circuit of the wiring pattern. When it is more than several hundred μm, the dust becomes a shadow, the positive resist cannot be sufficiently exposed, and the transferred wiring pattern is short-circuited. Therefore, it is necessary to remove such dust from the pellicle 12, and conventionally, an operator uses an air gun or the like to remove nitrogen (N
₂ ) It was removed by spraying.

First, as shown in FIG. 1, the reticle 12 with a pellicle film is set on the transfer arm 13, and the transfer arm 1
By inserting 3 into the housing 11, the reticle 12 is inserted into the housing 11 through the insertion opening 16. At this time, the reticle 12 is inserted far enough into the air nozzle 14 (FIG. 2).

Next, from the air nozzle 14 at a predetermined pressure, N
Gas such as ₂ is discharged, and at the same time, the inside of the housing 11 is exhausted from the exhaust port 15. After that, by pulling out the transport arm 13 at a predetermined speed, the dust adhering to the pellicle surface and the back surface of the reticle 12 can be blown off, and the blown dust is discharged from the exhaust port 15 to the outside of the housing 11.

The air nozzles 14 are wider than the lateral width of the reticle 12, and the nozzle outlets are arranged in a line. N ₂ is discharged from all the outlets, and in this state the reticle 12 moves at a constant speed. Since it is pulled out of the housing 11, dust on the entire surface of the reticle 12 can be removed.

As described above, in the case of the present invention, a plurality of air outlets arranged in a row are provided, and the air nozzle having the width of the reticle as a whole is about 1 to 2 cm is provided, and the air nozzle is provided in the entire lateral direction of the reticle. N ₂ can be sprayed.
Therefore, by pulling out the transport arm at a constant speed, it is possible to remove dust on the entire surface of both the pellicle surface and the back surface of the reticle at the same time, and it is possible to remove foreign matter adhering to the reticle very efficiently. .

Further, the transfer arm need only be moved from the state in which the reticle is inserted into the housing in the front direction of the housing (X direction: left-right direction with respect to the paper surface), and the movement in the Y direction (direction perpendicular to the paper surface). Since it does not have a carrier system, the structure of the carrier system is simple and inexpensive.

Further, since the width of the housing does not move in the Y direction, the reticle cleaning device can be smaller and the area occupied by the device can be smaller than that in the case of Japanese Patent Laid-Open No. 2000-98589.

As described above, according to the present invention, the dust removing operation is efficient, the structure of the transport system is simple, the apparatus can be made inexpensive, and the area occupied by the apparatus can be small.
It is superior to the reticle cleaning device disclosed in Japanese Patent Publication No. 98589.

If the cleaning device and the exposure device and the dust inspection device are connected by a clean tunnel whose cleanliness is maintained so that the reticle can be transported without being exposed to the atmosphere, dust can be transferred to the cleaned reticle. It is possible to convey and set to the exposure device or the dust inspection device without attaching foreign matter.

[0046]

As described above, by using the reticle cleaning device according to the present invention, it is possible to efficiently remove dust adhering to the pellicle surface and the reticle back surface without damaging the pellicle film. By using this reticle, it is possible to prevent a pattern short-circuit of a semiconductor substrate that is exposed to light, and consequently improve the yield of semiconductor devices formed on this semiconductor substrate.

Further, since the damage of the pellicle film is eliminated, it is possible to suppress wasteful expenses due to replacement of the pellicle film and purchase of a new reticle.

[Brief description of drawings]

FIG. 1 is a side view of the reticle cleaning apparatus according to the embodiment of the present invention before the reticle is loaded into the housing.

FIG. 2 is a side view of the reticle cleaning apparatus according to the embodiment of the present invention with the reticle carried in the housing.

FIG. 3 is a top view of FIG.

FIG. 4 is a graph showing the relationship between the wind pressure of nitrogen (N ₂ ) blown onto the pellicle surface and the dust removal rate, and the relationship between the pellicle film damage rate.

FIG. 5 is a schematic diagram showing the role of the pellicle film during exposure in the manner of the difference in the image formation point depending on the presence or absence of the pellicle.

FIG. 6 is a schematic view showing a method for cleaning a reticle by a conventional method.

FIG. 7 is a schematic diagram showing a conventional example in which an air blow method is used as a method for cleaning a reticle with a pellicle film.

[Explanation of symbols]

11,111,131 housing 12,112 reticle 12a reticle substrate 12b chrome pattern 12c gold frame 12d pellicle membrane 13,113 Transport arm 14,114 Air nozzle 15,115 exhaust port 16 insertion slot 17, 117 foreign matter 18 lenses 19 Image point 20 Semiconductor substrate 21 air gun 103 reticle case 106a, 106b reticle stage 107 laser light source 108 scattered light detector

Claims (7)

[Claims] 1. A housing, a transport device for transporting a reticle into the housing, a gas spraying device in the housing for spraying a gas onto the reticle carried into the housing, and mounted around the housing. A reticle cleaning device for ejecting a gas using the gas spraying device to remove foreign matter attached to the reticle, wherein the gas spraying device cleans at least one side of the reticle. A reticle cleaning device having a plurality of gas blowing ports arranged in a range including the reticle cleaning device. 2. The step of injecting gas using the gas blowing device to remove foreign matter adhering to the reticle, the carrying device carrying the reticle into the housing at a predetermined speed, and carrying the carrying device. 2. The reticle cleaning apparatus according to claim 1, wherein the reticle is scanned by scanning the inside of the housing while the reticle receives the air blow on the entire surface thereof. 3. The reticle cleaning device according to claim 1, wherein the gas blowing device has the gas blowing ports on both sides of the reticle. 4. The gas blowing port is composed of an air nozzle, and the air nozzle is set to have an interval of 10 to 15 mm with respect to the surface of the reticle and an angle of the air nozzle with respect to the surface of the reticle of 30 to 60 °. The reticle cleaning device according to claim 1, 2, or 3. 5. The reticle cleaning device according to claim 4, wherein the discharge pressure of the gas injected from the air nozzle is set to 0.3 to 0.7 kgf / cm ² . 6. The pellicle that constitutes a surface of the reticle by protecting the reticle so as to cover the glass substrate, a light-shielding film pattern formed on one surface of the glass substrate, and the light-shielding film pattern. A membrane having a membrane.
The reticle cleaning device according to any one of 1. 7. The reticle cleaning device according to claim 1, wherein the gas blowing ports are arranged in parallel to at least one side of the reticle.