JP2008298850A - Photomask storage method, photomask stocker, and method for manufacturing semiconductor device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a photomask storage method for preventing a foreign matter from growing by eliminating outgassing causing the foreign matter growing in a space in a pellicle film of photomask without requiring an inspection for checking the presence of the growing foreign matter of the photomask and washing for removing the growing foreign matter. <P>SOLUTION: In this photomask storage method, the photomask 10 provided with a ventilation hole 15 connecting the space 18 in the pellicle film with the outside is stored in a pellicle frame 13 constituting the photomask 10, and the photomask stocker 30 storing the photomask has a function for controlling air pressure in its inside to reduce pressure of the atmosphere in the photomask stocker 30, keep normal pressure, and boost it repeatedly and replace the atmosphere in the space 18 in the pellicle film with the atmosphere supplied from the outside and having high cleanliness. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a photomask storage method for replacing an atmosphere in a pellicle film during storage of a photomask used in a semiconductor device manufacturing process, a photomask stocker using the photomask storage method, and a photo using the photomask storage method The present invention relates to a method for manufacturing a semiconductor device using a mask.

In recent years, the required specifications of photomasks have become stricter as the semiconductor industry is upgraded (high integration, high precision, high performance). Correspondingly, the exposure wavelength of the scanner or stepper becomes shorter and the exposure energy tends to increase.
When the photomask is continuously irradiated with ultraviolet rays having high exposure energy, growth foreign matter (generally also referred to as HAZE) is generated in the photomask. The growing foreign matter starts to be generated as a fine foreign matter and grows and becomes larger by continuing the ultraviolet irradiation.
When the growth foreign matter adheres to the surface of the photomask, when the predetermined pattern is transferred to the semiconductor substrate, the portion where the growth foreign matter is attached is transferred as a part of the pattern. It becomes a defect. In particular, since the defect on the pattern surface is repeatedly transferred to the wafer, it becomes a common defect and the influence on the manufacture of the semiconductor device is very large.
After the pellicle film is mounted on the photomask, various substances (hereinafter referred to as outgas) are generated in the space in the pellicle film. Examples of outgas include an adhesive for the pellicle film, an adhesive for the inner wall of the pellicle frame, an adhesive for the reticle, a solvent remaining in the photomask, and SO ₄ contained in the remaining chemical solution such as a chemical. Is mentioned. Outgas and the like increase in the space in the pellicle membrane over time, and accumulate while gradually concentrating. These outgasses and the like are liable to cause a chemical reaction with a substance generally present in the air atmosphere, such as ammonia. For example, SO ₄ such as outgas reacts with ammonia NH ₃ to generate a substance such as ammonium sulfate on the surface of the photomask, and further, driving energy is obtained by exposure light (such as ultraviolet rays) of a scanner or the like to promote the reaction. Growing foreign matter that grows and affects the manufacture of the semiconductor device is formed.

As described above, the growth foreign matter is generally formed by photochemical reaction of gas in the atmosphere or residual chemical remaining in the photomask when the photomask is irradiated with exposure light from an exposure apparatus such as a scanner. A foreign material that grows. At present, as one of countermeasures against the generation of growth foreign substances, it is required to suppress these outgases and the like, and improvement of the material of a member used for a photomask is performed. However, it is difficult to completely eliminate the outgas and the like, and it is impossible to prevent the outgas from accumulating in the atmosphere of the pellicle film space over time. Therefore, when a growth foreign substance is generated, as a countermeasure, the growth foreign substance is often removed by maintenance by re-cleaning.
During the use of the photomask that has been used repeatedly, it is very inefficient to inspect and clean the growing foreign matter each time in the use of the photomask and the manufacture of the semiconductor device. This is a major factor in reducing productivity.
Maintenance such as cleaning needs to be performed continuously as long as it is used as a photomask. For maintenance by cleaning, the pellicle film must be replaced. To replace the pellicle film, it is necessary to peel the pellicle firmly attached to the light-transmitting substrate with an adhesive material from the light-transmitting substrate, scratching the light-transmitting substrate, contamination due to cleaning of the adhesive residue, etc. With risk. In addition to re-cleaning, photomask maintenance can only be performed one by one for each photomask, and it is not practical to deal with photomasks stored in large quantities, and maintenance costs are also high. It will be a big cost.

  Therefore, as a countermeasure against the growth foreign matter, for example, in Patent Document 1, the two opposing plates are each made of a light transmissive material, and the inside is filled with a purge gas made of an inert gas containing a predetermined amount of active gas. A photomask storage device is disclosed that has a housing that can store a photomask and an adjusting means that can adjust the air pressure inside the housing. Also, the pressure control is performed only by reducing the pressure to prevent the backflow of the inert gas. In Patent Document 2, a plurality of ventilation holes are provided in a structure that surrounds a gas replacement space to be replaced with an inert gas by a surrounding member, and the inside of the container forming the space around the structure is filled with the inert gas. Discloses an inert gas replacement method in which an inert gas is allowed to enter the gas replacement space and the gas replacement space is replaced with an inert gas. In the cited document 2, pressure control is performed inside and outside the chamber (exposure apparatus chamber) and outside the chamber only to prevent back flow from the exhaust port. In Patent Document 3, a reticle drying device is provided in an exposure apparatus, and the reticle is used so as not to come into contact with a drying source using a holding unit in the reticle drying device before mounting the reticle on the reticle stage of the exposure unit. A reticle drying apparatus is disclosed that heats and drys a reticle using a drying source while maintaining the pressure in the chamber, reducing the pressure in the chamber using an exhaust mechanism, and purging the chamber using a purge mechanism. As the pressure of the atmosphere, the pressure is only reduced to promote drying. In Patent Document 4, at least one of the pressure of an inert gas supplied to the supply nozzle, the pressure of the gas discharged from the discharge nozzle, the pressure of the inert gas supplied into the surrounding means, and the pressure of the gas discharged from the surrounding means is used. An exposure apparatus having pressure control means for controlling is disclosed. In the cited document 4, the atmosphere is replaced by taking in air from one side and exhausting from the other side, and does not control the pressure.

JP2002-299220 JP 2003-228163 A JP 2004-170802 A JP2006-060037

However, in the cited document 1, the number of molecules is reduced while maintaining the concentration of the active gas in the chamber, and the pressure control is only a reduced pressure to prevent the backflow of the active gas. In Cited Document 2, there is a description of pressure control, but it is only pressure control inside and outside the chamber (exposure apparatus chamber) and the purpose of preventing backflow from the exhaust port. Therefore, control is always performed so that one is positive pressure and the other is negative pressure. Cited Document 3 describes that the pressure is reduced to promote drying. In the cited document 4, two vent holes are provided in the pellicle frame, and the atmosphere is replaced by sucking air from one side and exhausting air from the other side. In addition, since the atmosphere is replaced for each photomask, work efficiency is poor. In any of the inventions described in any of the above cited references, it is difficult to efficiently suppress the generation of growth foreign substances.
SUMMARY OF THE INVENTION Accordingly, the present invention provides a photomask storage method that suppresses the generation of growth foreign substances by removing outgas that causes the growth foreign substances generated in the space inside the pellicle film of the photomask. It is an object to provide a photomask storage method and a photomask stocker that do not perform the inspection for the presence or absence of growth foreign substances on the photomask, and the cleaning for removing the growth foreign substances.
Furthermore, it is possible to suppress the generation of the growth foreign matter even if the photomask used in the manufacturing process of the semiconductor device is repeatedly used, and to inspect the photomask for the presence or absence of the growth foreign matter, and to provide a cleaning process for removing the growth foreign matter. There is provided a method for manufacturing a semiconductor device.

The features of the present invention, which is a means for solving the above problems, are listed below.
The present invention provides a photomask stocker for storing and storing a photomask provided with a vent hole that connects the pellicle membrane space and the outside to the pellicle frame constituting the photomask, and has a function of controlling the internal atmospheric pressure. This is a photomask storage method in which the atmosphere in the pellicle film is replaced with an atmosphere of high cleanliness supplied from the outside by repeatedly reducing the pressure in the mask stocker, normal pressure, and pressurization.
By making the atmosphere inside the pellicle always a clean atmosphere, it is possible to eliminate outgassing as a cause of growth foreign substances. In an environment where the photomask is stored in the stocker, the atmosphere in the pellicle film space can be cleaned, and continuous implementation becomes possible. As a prevention and countermeasure against the occurrence of growth foreign substances, the maintenance of one sheet or one sheet becomes unnecessary, and the reticle quality that is effective in terms of cost and man-hour can be maintained in a high state. As a result, it is possible to eliminate the adverse effect on transfer due to simple foreign matters such as dust.

The present invention is also a photomask stocker for storing and storing a photomask, wherein the atmosphere in the photomask stocker is repeatedly reduced, normal, and pressurized, and each photomask has an atmosphere in the pellicle film. It is a photomask stocker provided with a counter that counts a predetermined number of times of replacement.
By substituting the atmosphere in the pellicle film a predetermined number of times, the outgas concentration can be lowered until generation of growth foreign substances can be suppressed. Further, by providing a counter for counting the number of times the photomask is replaced, a large number of photomasks can be managed simultaneously.

The present invention also relates to a method of manufacturing a semiconductor device for manufacturing various semiconductor elements, magnetic device elements, dielectric device elements, etc. by transferring a circuit pattern shape such as an element / wiring pattern onto a wafer using a photomask. .
By using a photomask by this photomask management method, pattern errors due to growing foreign matter in the exposure (photolithography) process can be reduced.

As described above, according to the present invention, it is possible to eliminate outgas, which is a cause of occurrence of long foreign matters, and thus it is possible to manage a photomask that does not need to be inspected one by one when used in a semiconductor device manufacturing process. A method and photomask stocker could be provided.
Further, according to the present invention, even if the photomask is used repeatedly, the generation of the growth foreign matter is suppressed, and the semiconductor device without the inspection for the presence of the growth foreign matter in the photomask and the cleaning step for removing the growth foreign matter is not provided. We were able to provide a manufacturing method.

The best mode for carrying out the present invention will be described below with reference to the drawings. Note that it is easy for a person skilled in the art to make other embodiments by changing or modifying the present invention within the scope of the claims, and the following description is an example of the best mode of the present invention. It is not intended to limit the scope of the claims.
In the present invention, a pellicle frame 13 is provided on a surface of a translucent substrate 11 where a pattern 14 to be transferred to a transfer object is formed, and the photomask 10 having a pellicle film 12 provided on the pellicle frame 13 is a photomask. In the method of storing the photomask stored in the stocker 30, the pellicle frame 14 is provided with the air holes 15 for sucking and exhausting the atmosphere, and the pressure in the photomask stocker 30 is increased and / or reduced, and this is repeated. The photomask management method replaces the atmosphere of the pellicle film inner space 18 formed by the translucent substrate 11, the pellicle frame 13, and the pellicle film 12.
FIG. 1 is a schematic view showing the structure of a photomask. A pellicle film 12 is attached to the photomask 10 in order to prevent adhesion of foreign matters such as simple dust and dirt. The pellicle film 12 is a metallic outer frame, and a thin transparent film of an organic thin film such as nitrocellulose is stretched on one opening of the pellicle frame 13 by an adhesive such as polybutene resin, polyvinyl acetate resin, or acrylic resin. ing. The pellicle frame 13 is provided with a ventilation hole 15 for adjusting ventilation that penetrates the inner surface and the outer surface. A filter 16 is provided in the vent hole 15 to prevent foreign matter (dust) existing in the outer surface atmosphere from entering the inner surface through the vent hole 15. A similar adhesive is applied to the pellicle frame 13 at the opening opposite to the pellicle film 12 side in order to attach the pellicle frame 13 to the translucent substrate 11. In addition, an adhesive for trapping foreign matter (dust) may be applied to the inner wall portion of the pellicle frame 13. A glass substrate is used as the translucent substrate 11. As the pattern 14, a vacuum-deposited metal film such as aluminum or chromium is used. The pellicle frame 13 is made of an aluminum alloy whose surface is anodized.
Ultraviolet rays irradiated on the reticle 10 by exposure in the photolithography process are incident from the surface side where the pattern 14 is not formed, and are incident on the surface side where the pattern 14 is formed. Others pass through the interface between the translucent substrate 10 and the pellicle film 12, enter the pellicle film 12, and exit to the outside.

FIG. 2 is a schematic diagram showing the configuration of the photomask stocker. When the photomask 10 with the vericle film 12 is stored in the photomask stocker 30, it is stored in the storage unit 35 in the photomask stocker 30, as shown in FIG. The photomask stocker housing 31 includes an intake portion 32 that supplies an external atmosphere to the storage portion 35 and an exhaust portion 33 that exhausts the internal atmosphere from the storage portion 35. The intake section 32 and the exhaust section 33 are connected to a fan or a blower 323 of a pump by removing a simple foreign matter such as dust by sandwiching a filter 322 at an intake port 321. The air blowing means 323 is operated by an operation panel 34 provided outside the photomask stocker 30. A timer or counter 37 is further provided outside the photomask stocker 30 to measure the time when the photomask 10 is stored or the number of intake / exhaust times.
Further, a sign is assigned to the storage unit 35 for each place where the photomask 10 is stored, and the time of the photomask 10 placed at the position of the sign is measured. Thereby, the time stored in the photomask stocker 30 of the photomask 10 and the like can be clarified, and it can be clarified whether the atmosphere in the space in the pellicle film 12 has been replaced.
Although FIG. 2 shows a photomask stocker having a configuration including an intake hole and an exhaust hole, this is merely an example, and the pressure in the stocker can be reduced and / or increased even without such a configuration. Any structure can be used, and for example, a structure in which intake and exhaust are performed using a common hole formed in the photomask stocker may be used. Further, pressurization and / or decompression may be performed by sucking and exhausting an inert gas such as Ar or N ₂ .

FIG. 3 is a diagram schematically showing the state of the reticle when the inside of the photomask stocker is evacuated and decompressed.
The atmosphere in the photomask stocker 30 is exhausted from the exhaust port 33 and depressurized. However, the pellicle membrane space 18 of the reticle in the photomask stocker 30 is at the pressure before exhaustion, and the atmosphere of the pellicle membrane space 18 is exhausted through the vent hole 16, but the size of the vent hole 16, A predetermined time is required for the pressure of the atmosphere inside and outside the pellicle film 12 to be equal depending on the type of filter. Accordingly, the elastic pellicle film 12 swelled by being pressed by the atmospheric pressure in the pellicle film inner space 18 as shown in FIG. 3A until the pressure in the atmosphere inside and outside the pellicle film 12 becomes equal. It becomes a state. The amount of deflection when it swells is indicated by an arrow A. Moreover, the white arrow in FIG. 3 has shown the magnitude | size and direction of the pressure of atmosphere. Black arrows indicate the flow of the atmosphere.
However, when a predetermined time elapses, as shown in FIG. 3B, the pellicle film 12 returns to the flat original state, and at that time, a part 18 ′ of the pellicle film inner space indicated by hatching is exposed to the outside. Exhausted.
Thereafter, when the photomask stocker 30 is returned to the original atmospheric pressure state, similarly, a predetermined time is required for the pressures of the atmosphere inside and outside the pellicle film 12 to become equal. Therefore, until the pressure in the atmosphere inside and outside the pellicle film becomes equal, as shown in FIG. 3C, the elastic pellicle film is pressed by the atmospheric pressure in the space outside the pellicle film and is in a deflated state. Become. The amount of deflection when it is deflated is indicated by an arrow B ′. At this time, the amount of bending B ′ withering differs depending on the amount of exhausted atmosphere, but it does not become larger than the amount of bending A in FIG.
However, when a predetermined time elapses, as shown in FIG. 3D, the pellicle film 12 returns to the flat original state, and at that time, a part 18 ″ of the space in the pellicle film indicated by oblique lines is externally applied. Inhaled.
In this way, the atmosphere of the pellicle film inner space 18 can be exchanged by performing normal pressure and reduced pressure with the photomask stocker 30. In particular, by drawing air into the pellicle membrane space 18, the concentration of the outgas and the like in the pellicle membrane space 18 can be reduced and then exhausted, so that the outgas and the like can be exhausted simultaneously. By exhausting the outgas and the like, the concentration of the outgas remaining in the pellicle film space 18 can be reduced, and the generation of the growth foreign matter 20 can be suppressed.

FIG. 4 is a diagram schematically showing the state of the reticle when the inside of the photomask stocker is sucked and pressurized.
The atmosphere in the photomask stocker 30 is sucked from the air inlet 32 and pressurized. However, the space 18 in the pellicle membrane of the photomask 10 in the photomask stocker 30 is at the pressure before the intake, and the atmosphere in the space 18 in the pellicle membrane 18 is sucked through the vent 16, but the size of the vent 16 is large. Depending on the type of the filter 17, a predetermined time is required for the pressure in the atmosphere inside and outside the pellicle film 18 to be equal. Therefore, before the pressure of the atmosphere inside and outside the pellicle film 12 becomes equal, as shown in FIG. 4A, the elastic pellicle film 12 is deflated by being pressed by the atmospheric pressure in the space outside the pellicle film. It becomes a state. The amount of flexure when deflated is indicated by an arrow B. The white arrows in FIG. 4 indicate the magnitude and direction of the atmospheric pressure. Black arrows indicate the flow of the atmosphere.
However, when a predetermined time elapses, as shown in FIG. 4B, the pellicle film 12 returns to the original flat state, and at that time, a part 18 ′ of the pellicle film inner space 18 shown by the oblique lines is removed from the outside. Inhaled from.
Thereafter, when the photomask stocker 30 is returned to the original atmospheric pressure state, similarly, a predetermined time is required for the pressures of the atmosphere inside and outside the pellicle film 12 to become equal. Accordingly, the elastic pellicle film 12 is pushed by the atmospheric pressure in the pellicle film inner space 18 and swells as shown in FIG. 4C until the pressures of the atmosphere inside and outside the pellicle film 18 become equal. It becomes a state. The amount of deflection when it swells is indicated by an arrow A. At this time, the swelling deflection amount A ′ varies depending on the exhausted atmosphere amount, but it does not become larger than the deflection amount B in FIG. 4A in the pressurized state.
However, when a predetermined time elapses, as shown in FIG. 4D, the pellicle film 12 returns to the original flat state, and at that time, a part 18 ″ of the pellicle film inner space 18 indicated by hatching is inside. It is exhausted from.
In this way, the atmosphere of the pellicle film inner space 18 can be exchanged by performing normal pressure and pressurization with the photomask stocker 30. In particular, when the pellicle membrane space 18 is exhausted, the concentrated outgas generated in the pellicle membrane space 18 can be exhausted simultaneously. Furthermore, by reducing the concentration of the outgas remaining in the pellicle film inner space 18 by inhaling, generation of the growth foreign substance 20 can be suppressed.

FIG. 5 is a diagram schematically showing the state of the reticle when the inside of the photomask stocker is inhaled and pressurized, and further exhausted and depressurized.
The atmosphere in the photomask stocker 30 is sucked from the air inlet 32 and pressurized. However, the space 18 inside the pellicle film of the reticle in the photomask stocker 30 is at the pressure before inhalation, and the atmosphere in the space 18 inside the pellicle film is inhaled through the vent hole 16, but the atmosphere inside and outside the pellicle film 12. Until the pressure becomes equal, as shown in FIG. 5A, the elastic pellicle membrane is pressed by the atmospheric pressure in the pellicle outer space 18 and is in a deflated state. The amount of flexure when deflated is indicated by an arrow B.
However, when a predetermined time has elapsed, the pellicle film 12 returns to the flat original state, and at that time, a part 18 ′ of the pellicle film inner space 18 indicated by oblique lines is sucked from the outside.
However, before the pellicle film 12 becomes the original flat state, when the photomask stocker 30 is exhausted and depressurized, the elastic pellicle film 12 is pushed by the atmospheric pressure of the pellicle film inner space 18. As shown in FIG. 5 (b), it swells and reaches a state of a deflection amount A. Accordingly, in order to make the pressure inside and outside the pellicle film 12 the same, a part 18 ′ ″ of the atmosphere including the outgas in the pellicle film inner space 18 is exhausted.
At this time, an intermediate state in which the pellicle film 12 becomes flat may be used. Furthermore, the amount of the atmosphere to be exhausted can be increased and the atmosphere can be exchanged efficiently by changing the intermediate state from the deflated state to the inflated state while passing slowly.
Furthermore, by applying the pressure without bringing it into the normal pressure state, the elastic pellicle film 12 is pressed by the atmospheric pressure of the pellicle film outer space 18 and becomes deflated as shown in FIG. 5C. In this state, the atmosphere inside the pellicle membrane space 18 is inhaled with a larger amount of atmosphere than when the normal pressure state is changed to the reduced pressure state, so that the concentration of outgas remaining in the pellicle membrane space 18 can be greatly reduced. The generation of the growth foreign material 20 can be suppressed.

At this time, by repeating suction and exhaust in normal pressure / depressurized state, normal pressure / pressurized state, normal pressure / pressurized / depressurized state, concentration of outgas etc. in the pellicle membrane space 18 is prevented, Further, the concentration of outgas or the like can be reduced.
In addition, it is preferable that the volume to be sucked and exhausted at one time is repeated to 10% or less with respect to the space 18 in the pellicle membrane. In the inner space 18 of the pellicle film, outgas or the like is continuously generated from the adhesive or the like, and in order to eliminate this continuously and to always keep the concentration below the concentration at which the growth foreign substance 20 is generated, 2 % Or more is preferably exhausted. If it is less than 2%, the concentration of generated outgas and the like gradually increases even if exhausted repeatedly, so that the growth foreign matter 20 may be generated even if the photomask has been stored for a long time.
Furthermore, the higher the volume that can be evacuated, the better, but there is a limit to the volume that can be evacuated at one time due to the strength of the pellicle film 12, the strength of the adhesive, the suction / exhaust capacity of the photomask stocker 30, and the like. In this case, with exhaust of 10% or less, the process is repeated at least nine times. By performing exhausting nine times or more, generation of the growth foreign material 20 can be suppressed.
Therefore, it is preferable to exhaust 9 to 45 times or more in the range of 2 to 10% before exposing to light such as ultraviolet light through the photolithography process. In the photomask stocker 30 of the present invention, by providing a timer or a counter, the number of exhausts of the pellicle film inner space 18 is measured, so that the concentration of outgas and the like is reduced before the growth of foreign substances 20 occurs. Can know. If the intake / exhaust speed is kept constant, the number of exhausts can be replaced by time, and even by measuring the time, it is known that the concentration of outgas and the like has decreased before the growth of the foreign material 20 occurs. be able to.

In order to prevent the pellicle film 12 from loosening, the pressurization or depressurization speed in the photomask stocker 30 is set to 7.31 hPs / min. Control with: As a means for controlling the pressure, the pressure in the photomask stocker 30 is controlled by controlling any one or a combination of the intake air supply amount, the intake air supply speed, the intake air supply pressure, the exhaust gas discharge amount, the exhaust gas exhaust speed, and the exhaust gas exhaust pressure. Fluctuate. In FIG. 2, the flow rate / speed or pressure is controlled from above the operation panel by controlling the fan or pump via the operation panel 34. As a control amount of the pressure in the photomask stocker 30, it is necessary to control the pressure fluctuation so that the pellicle film 12 does not loosen. As a control amount of the pressure in the photomask stocker 30, it is necessary to control the pressure fluctuation so that the pellicle film 12 does not bend. For example, reduced pressure or increased pressure is 7.31 hPs / min. By setting the following amount of change, the amount of bending of the pellicle film 12 is managed, and the speed of pressure increase / decrease is controlled within a range in which the pellicle film is not plastically deformed. Furthermore, it has been found that when the pressurization / decompression is controlled at this speed, the pellicle film 12 does not loosen. The pellicle film 12 is a highly translucent resin such as nitrocellulose or fluoropolymer, and has a thickness in the range of 0.8 to 2.0 μm.
Further, the amount of bending of the pellicle film 12 is set to ± 2 mm or less. In addition, it is necessary to control the amount of bending of the pellicle film 12 and to control the pressure reduction pressure in a range where the pellicle film 12 is not plastically deformed. When the pellicle film 12 is provided on the pellicle frame 13, if the deflection amount exceeds ± 2 mm, the pellicle film 12 may be peeled off during repeated suction and exhaust. Furthermore, if the amount of deflection exceeds ± 2 mm, plastic deformation may occur, making it impossible to reuse. This amount of change can be controlled by the diameter and quantity of the pressure adjusting hole of the pellicle frame 13, the fineness of the filter, and the like.

Next, a manufacturing process of a semiconductor device using a photomask stored by the photomask storage method will be described. FIG. 6 is a flowchart showing the overall manufacturing process of the semiconductor device. First, in the design process, a circuit design of a semiconductor device that matches the use and characteristics is performed (step S1). In the mask manufacturing process, a photomask is manufactured based on the design pattern of the circuit design (step S2).
On the other hand, in the wafer manufacturing process, a wafer to be a substrate of a semiconductor device is manufactured using a material such as silicon (step S3). Next, in the wafer processing step, an actual circuit is formed on the wafer by lithography using the photomask and the wafer (step S4).
In this wafer processing step, for example, in resist processing, a photosensitive agent is applied to the wafer (step S81). In the next exposure process, the circuit pattern is transferred to the resist on the wafer using the photomask 10 by the exposure apparatus (step S82). In the development process, the exposed wafer is developed and fixed (step S83). In the next cleaning step, the resist that has become unnecessary after the etching is cleaned and removed (step S84). These processes are appropriately used between processes such as oxidation in the wafer processing process.
In the oxidation step, the surface of the wafer provided with the resist is oxidized (step S91). In the CVD process, an insulating film is formed on the wafer surface (step S92). In the ion implantation process, ions are implanted into the wafer (step S93). Further, in the etching process, the wafer surface is etched to form a predetermined circuit pattern or electrodes are formed (step S94).
By repeating these steps, multiple circuit patterns are formed on the wafer.
Next, the assembly process includes assembly processes such as an assembly process (dicing, bonding), a packaging process (chip encapsulation), and the like, and a semiconductor chip is formed using the manufactured wafer (step S5). In the inspection process, inspections such as an operation confirmation test and a durability test of the manufactured semiconductor device are performed (step S6). Through these steps, the semiconductor device is completed and shipped (step S7).

FIG. 7 is a schematic diagram for explaining a situation where a growth foreign substance is generated in the photomask. Among these, the growth foreign matter 201 and 202 on the photomask 10 is in the outgas etc. remaining in the pellicle film space 18 and in the photomask stocker 30, in the scanner / stepper, in the clean room, in the reticle transport case, etc. , SO ₄ , NO _x (where X is a natural number) ions, and the like.
By irradiating high-energy ultraviolet rays with a scanner / stepper where these substances exist, a photochemical reaction is caused, and substances represented by ammonium sulfate and the like are generated, and so-called growth foreign substances 20 are generated. And deposited on the photomask 10. Further, the growth foreign material 20 on the photomask 10 starts to be generated on the surface where the pattern 14 is not present. Thereafter, when the exposure to ultraviolet rays is continued, after the foreign matter on the surface of the translucent substrate 11 grows to some extent, the growth foreign matter 20 occurs on the pattern surface where the pattern 14 of the reticle 10 exists. Since the growth foreign substance 20 on the translucent substrate 11 is not a focus surface in the case of exposing with a scanner / stepper, the influence on the yield on the wafer is small unless it grows large. Further, since the growth foreign substance 20 on the pattern surface is located between the translucent substrate 11 and the pellicle film 12 and cannot grow in the height direction, the space between them grows in the horizontal direction. For this reason, the pattern 14 and the pattern 14 may be connected. When this pattern is transferred to the wafer, the pattern 14 to which circuits, wirings, and the like are connected is formed on the wafer, resulting in a defect in the semiconductor device. . In the present invention, irradiation with high-energy ultraviolet rays by a scanner / stepper is unavoidable in the manufacture of a semiconductor device. Therefore, the growth foreign substance 20 is replaced by replacing outgas generated in the pellicle film inner space 18. Occurrence of the occurrence of defects in semiconductor device manufacturing is prevented. Further, by omitting the step of inspecting the photomask 10 for the presence of the growth foreign material 20 before using it in the photolithography process, it is possible to increase the throughput in manufacturing the semiconductor device.

  In addition, since gases generated from cases for storing the photomask 10 and transporting jigs such as POD also have the same problem, the photomask 10 is provided with a vent 16 (filter) 16 for outside air, and the case is stored at the time of storage. It is also possible to apply the photomask storage method of the present invention by replacing the atmosphere in the jig.

Although the present invention has been described with reference to the preferred embodiments, the present invention is not limited to such specific embodiments, and various modifications and changes can be made within the scope described in the claims. The features of the present invention are listed below.
(Appendix 1)
A photomask provided with a translucent substrate having a pattern to be transferred to a transfer target, a pellicle frame formed on the translucent substrate and having a vent, and a pellicle film supported by the pellicle frame In the photomask storage method of storing in the photomask stocker,
A photomask storage method, wherein pressurization and / or decompression are repeated in the photomask stocker.
(Appendix 2)
In the photomask storage method according to attachment 1,
A photomask storage method, wherein 10% or less of the space in the pellicle membrane is sucked or exhausted by one pressurization or decompression.
(Appendix 3)
In the photomask storage method according to appendix 1 or 2,
A method of storing a photomask, wherein the intake and exhaust of the photomask is repeated nine times or more while the photomask is stored in the photomask stocker.
(Appendix 4)
A photomask provided with a translucent substrate having a pattern to be transferred to a transfer target, a pellicle frame formed on the translucent substrate and having a vent hole, and a pellicle film supported by the pellicle frame In the photomask stocker to store,
The photomask stocker is capable of pressurizing and / or depressurizing air pressure in the photomask stocker.
(Appendix 5)
In a method for manufacturing a semiconductor device,
The method for manufacturing a semiconductor device includes manufacturing a semiconductor device by transferring the pattern onto a semiconductor substrate using a photomask stored by the photomask storage method according to any one of appendices 1 to 3. A method for manufacturing a semiconductor device.
(Supplementary note 6) The photomask storage method according to supplementary note 1, wherein a filter is attached to the vent hole.
(Additional remark 7) The said photomask stocker performs the said pressurization and / or pressure reduction through the inlet port and exhaust port which a photomask stocker is equipped, The photomask stocker of Additional remark 4 characterized by the above-mentioned.

It is the schematic which shows the structure of a photomask. It is the schematic which shows the structure of a photomask stocker. It is the figure which represented typically the state of the reticle when the inside of a photomask stocker was exhausted and pressure-reduced. It is the figure which represented typically the state of the reticle when inhaling and pressurizing the inside of a photomask stocker. FIG. 6 is a diagram schematically showing the state of a reticle when the inside of the photomask stocker is inhaled and pressurized, and further exhausted and depressurized. It is a flowchart which shows the whole manufacturing process of a semiconductor device. It is the schematic for demonstrating the condition where the growth foreign material generate | occur | produces in a photomask.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Reticle 11 Translucent board | substrate 12 Pellicle film | membrane 13 Pellicle frame 14 Pattern 20 Growth foreign substance 30 Photomask stocker 31 Photomask stocker housing | casing 32 Inhalation part 321 Intake port 322 Filter 323 Blower means 33 Exhaust part 34 Operation panel 35 Storage part 36 timer

Claims (5)

A photomask provided with a translucent substrate having a pattern to be transferred to a transfer target, a pellicle frame formed on the translucent substrate and having a vent, and a pellicle film supported by the pellicle frame In the photomask storage method of storing in the photomask stocker,
A method of storing a photomask, characterized by repeating pressurization and / or decompression in the photomask stocker. The photomask storage method according to claim 1, wherein a filter is attached to the vent hole. A photomask provided with a translucent substrate having a pattern to be transferred to a transfer target, a pellicle frame formed on the translucent substrate and having a vent hole, and a pellicle film supported by the pellicle frame In the photomask stocker to store,
The photomask stocker is capable of pressurizing and / or depressurizing air pressure in the photomask stocker. The photomask stocker according to claim 3, wherein the photomask stocker performs the pressurization and / or decompression through an intake port and an exhaust port provided in the photomask stocker. In a method for manufacturing a semiconductor device,
A method for manufacturing the semiconductor device includes manufacturing a semiconductor device by transferring a pattern to a semiconductor substrate using the photomask stored by the photomask storage method according to claim 1. Manufacturing method.

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