JP4637968B2 - Method for producing photoresist composition - Google Patents

Description

The present invention relates to a method for manufacturing a photoresist composition.

In general, a chemically amplified photoresist composition using a KrF excimer laser, ArF excimer laser, F ₂ excimer laser, EUV (extreme ultraviolet light), EB (electron beam), or the like as a light source (radiation source) is disclosed in, for example, As described in Japanese Patent No. 296779 (Patent Document 1), a resin component (A), an acid generator component (B) that generates acid upon exposure, and an organic solvent (C) that can dissolve these components Is included.
Such a chemically amplified photoresist composition is required to have high resolution, high sensitivity, and a resist pattern having a good shape.
In recent years, when a resist pattern with a high resolution of 0.15 microns or less is required, in addition to these characteristics, there is a defect (surface defect) of a resist pattern after development more than before. More improvement is needed.
This defect is a general defect detected when a developed resist pattern is observed from directly above with, for example, a surface defect observation apparatus (trade name “KLA”) manufactured by KLA Tencor. This defect is, for example, a scum after development, bubbles, dust, a bridge between resist patterns, and the like.

In order to improve such defects, improvement has been attempted mainly focusing on resist compositions such as a resin component, an acid generator component, and a solvent component of a resist composition [JP-A-2001-56556]. Publication (Patent Document 2)].
In addition, the resist solution (photoresist composition in a solution state) has a foreign matter aging characteristic of the resist solution in which fine particles are generated during storage (while the photoresist composition is being stored, the solid foreign matter contained in the photoresist composition). Is also a problem, and improvement is desired.
In order to improve the foreign matter aging characteristics, as in the above, improvement has been attempted centering on the resist composition [Japanese Patent Laid-Open No. 2001-22072 (Patent Document 3)].

JP 2002-296679 A JP 2001-56556 A JP 2001-22072 A Japanese Patent Laid-Open No. 2002-62667 JP 2001-350266 A

However, the techniques described in Patent Documents 2 and 3 are not yet sufficient in their effects.
Furthermore, when the fine particles are generated, the defect may be caused, and it is strongly desired to improve the foreign matter aging characteristics for improving the defect.
However, a method for sufficiently improving the defect and storage stability of the resist pattern after this phenomenon has not been known so far.
Incidentally, JP-A-2002-62667 (Patent Document 4) discloses a method for producing a photoresist composition in which the amount of fine particles in the photoresist composition that circulates the line is reduced by passing the photoresist composition through a filter. Proposed.
As described in Patent Document 4, in the production of a photoresist composition, it is known that a photoresist composition is produced and passed through a filter. The resist pattern defect and storage stability cannot be improved sufficiently.
Japanese Patent Laid-Open No. 2001-350266 (Patent Document 5) proposes a method for producing a photoresist composition that passes through a filter having a positive zeta potential. However, according to the examination of the present applicant, when a photoresist composition is processed by the method described in Patent Document 5, the composition may change. This change in composition is disadvantageous because it causes changes in the sensitivity of the photoresist composition and the resist pattern size.
In recent years, among resist pattern defects after the phenomenon, a fine resist pattern such as a resist pattern of 130 nm or less using ArF excimer laser or the like, that is, ArF excimer laser, F ₂ excimer laser, EUV, EB, etc. In the case of forming, the problem of defect resolution becomes more severe.
That is, it has become an extremely important problem to suppress defects such as fine scum and microbridge after development, which has not been a major problem with resists for KrF excimer lasers. However, none of the above-mentioned prior arts have sufficiently solved.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a technique for obtaining a photoresist composition capable of suppressing defects in a resist pattern after development, particularly generation of fine scum and microbridge. .
It is another object of the present invention to provide a technique for obtaining a photoresist composition having excellent foreign matter aging characteristics (storage stability).
More preferably, it is an object of the present invention to provide a technique for obtaining a photoresist composition in which changes in sensitivity and resist pattern size hardly occur before and after processing.

In order to achieve the above object, the present invention employs the following configuration.
The present invention (seventh invention (embodiment)) is derived from a structural unit (a1) derived from a (meth) acrylic acid ester having an acid dissociable, dissolution inhibiting group and a (meth) acrylic acid ester having a lactone ring. A resin component (A) having a structural unit (a2) and a structural unit (a3) derived from a (meth) acrylic acid ester having a hydroxyl group and / or a cyano group, and acid generation that generates an acid upon exposure Passing the photoresist composition containing the agent component (B) and the organic solvent (C) through a first filter having a first film made of a nylon film having a pore diameter of 0.04 μm or less, In addition, before or after the step of passing the first filter, the photoresist composition is further passed through a second filter having a second film made of polyolefin resin or fluororesin. A method for producing a photoresist composition characterized by having a that process.
The defect appears only in the resist pattern, and is different from the pinhole defect in the resist coating film before the so-called pattern formation.
In the present specification, (meth) acrylic acid represents one or both of acrylic acid and methacrylic acid. Moreover, a structural unit shows the unit induced | guided | derived from the monomer which comprises a polymer.

ADVANTAGE OF THE INVENTION According to this invention, the technique which can obtain the photoresist composition which can suppress the defect of the resist pattern after image development, especially generation | occurrence | production of a fine scum and microbridge can be provided.
In addition, it is possible to provide a technique for obtaining a photoresist composition having excellent foreign matter aging characteristics (storage stability).
More preferably, it is possible to provide a technique for obtaining a photoresist composition in which a change in sensitivity and resist pattern size hardly occurs before and after processing.

It is the schematic block diagram which showed an example of the filtration apparatus of this invention. It is the schematic block diagram which showed an example of the coating device carrying the filtration apparatus of this invention. It is a graph of Zisman Plot.

First Embodiment [Operation Procedure and Device]
Hereinafter, an example of the method for producing a photoresist composition and a filtration apparatus of the present invention will be described in accordance with the procedure.
First, as a filtration device, a first filtration unit having a first filter having a first membrane (filtration membrane) having a zeta potential in the range of −20 mV and 15 mV or less in distilled water having a pH of 7.0. And what prepares the 2nd filtration part provided with the 2nd filter which has the 2nd membrane (filtration membrane) made of polyethylene or polypropylene is prepared.
The zeta potential is the potential of the diffusion ion layer generated around the charged particles in the liquid.
More specifically, when the ultrafine powder has a charge in the liquid, ions of opposite charges are attracted to the fine powder by electrostatic force to cancel the charge, and an electric double layer is formed. The potential on the outermost surface of this double layer is the zeta potential.
The zeta potential measurement is said to be effective for determining the surface structure of fine powders and fine particles. Hereinafter, the term “zeta potential” simply means “zeta potential in distilled water at pH 7.0”. The numerical value in the present invention is the nominal value of the filter manufacturer.
And in the said 1st Embodiment, the filter provided with the film | membrane of a specific range is used for the zeta potential made into such a filter manufacturer's nominal value, It is characterized by the above-mentioned.
By using a film having such a specific zeta potential, the effect of reducing defects, particularly fine scum and microbridges, and suppressing foreign matter aging can be obtained.

In the present invention, the filter includes, for example, at least a film that allows a photoresist composition to pass therethrough and a support member that supports the film, and is manufactured by Nippon Pole Co., Ltd., Advantech Toyo Co., Microlith Co., Ltd., or KITZ. Various materials and pore diameters are manufactured or sold by filter manufacturers such as the company for filtering ultrapure water, high-purity chemicals, fine chemicals, and the like.
In the present invention, the photoresist composition passing through the filter may be a photoresist composition having the same concentration as that of the product, or a concept including a so-called stock solution having a solid content concentration of about 8 to 15% by mass before dilution.
In addition, the term “filtration” used in the present invention includes a chemical “filtration” (“permeate only a fluid phase [gas or liquid] using a porous membrane or phase”). In addition to the meaning of “separating a semi-solid or solid from the phase of a fluid” “Kyoto University Dictionary 9 July 31, 1962 Kyoritsu Publishing Co., Ltd.”, The case where the semi-solid phase or solid trapped by the membrane cannot be visually confirmed by passing through the membrane is also included.

And according to a conventional method, the photoresist composition containing the resin component (A), the acid generator component (B) which generates an acid by exposure, and the organic solvent (C) is prepared.
Thereafter, as shown in FIG. 1, when the photoresist composition is supplied from the storage tank 1 (photoresist composition storage part) to the first filtration part 2, the photoresist composition is contained in the first filtration part 2. The first filter 2 a provided in the first filter 2 a passes through the first membrane and is filtered, and the filtrate is supplied to the first filtrate storage tank 3. Next, when the filtrate (photoresist composition) is supplied from the first filtrate storage tank 3 to the second filtration unit 4, the filtrate is provided in the second filtration unit 4. In 4a, it is filtered through the second membrane.
Finally, the filtrate [photoresist composition] is put in a container 5 to obtain a product.
Here, although the 2nd filtration part 4 (2nd filter 4a) is not essential, by using the 2nd filter 4, the burden of filtration with the 1st filter 2a in the 1st filtration part 2 is carried out. This is preferable because it can be reduced, and the defect reduction effect and foreign matter aging characteristics are further improved.

The film of the second filter 4a is not particularly limited as long as it is conventionally used for the filtration application of a photoresist composition, for example, a fluorine resin such as PTFE (polytetrafluoroethylene); polypropylene, polyethylene, etc. A polyolefin resin such as nylon 6 (registered trademark), nylon 66 (registered trademark), and the like.
Among these, a film selected from polypropylene and polyethylene films is preferable when combined with the first filter, because both the effect of reducing defects and the characteristics of foreign matter aging are excellent. The polypropylene film includes a high density polypropylene (HDPE) film and an ultra high molecular weight polypropylene (UPE) film in addition to the normal polypropylene.

As a procedure for combining filtration by the second filter 4a after the step of filtering by the first filter 2a provided with the first membrane of the present invention, the first filtration unit 2 of the present invention includes The first filter 2a provided is first filtered, then supplied to the second filtration unit 4, and the second filtration 4a provided with, for example, a polyethylene or polypropylene membrane is subjected to the second filtration. And finally, it filters with the filter provided with the membrane made from PTFE. At this time, it is not necessary to perform filtration with a filter having a final PTFE membrane, but it is preferable to perform filtration. Also, before the step of filtering with the first filter 2a, the same as with the second filter 4a. It is also possible to provide a prefiltration step of filtering about once or twice using the above filter. The filter used in the prefiltration step is the same as the film of the second filter 4a described above, and a preferable film is selected from polypropylene and polyethylene films.

As a procedure for combining the specific pre-filtration by the second filter 4a and the step of passing the first filter 2a provided with the first membrane, for example, the filter is first filtered with a filter made of PTFE. Then, the second filtration 4a provided with a polyethylene or polypropylene membrane is used for the second filtration, and then supplied to the first filtration unit 2 and provided in the first filtration unit 2. The first filter 2a is used for filtration. At this time, it is not necessary to perform the filtration with the filter having the first PTFE membrane, but it is preferable to perform the filtration. In the present invention, the first filter 2a provided in the first filtration unit 2 is provided. You may use combining the operation filtered with the said 2nd filter 4a in both before and after filtration.

In the present invention, if filtering is performed at least once by the first filter 2a, excellent effects can be obtained in terms of defect reduction effect and foreign matter aging characteristics. The number of times of passage through the membrane (the number of times of filtration), the combination of filters provided with other types of membranes, and the like are not particularly limited, and can be appropriately adjusted according to the purpose.
In particular, it is preferable to perform filtration through the first filter 2a once or twice, and finally perform filtration through the second filter 4a, since both the effect of reducing defects and the foreign matter aging characteristics are excellent. In the case of performing filtration by the first filter 2a twice or more, an apparatus that passes the first filtration unit 2 once by a conventional method and supplies the filtered filtrate to the first filtration unit 2 again. The configuration may be as follows.
The configuration of the filtration device can be appropriately selected depending on the combination of filters in the filtration step, and the photoresist composition before and after filtration such as a reservoir is appropriately stored before and after one or more types of filters (filters). By providing a tank to do, it can be configured as various forms.

Various forms can be adopted for the filtration device of the present invention.
For example, it may be an apparatus used in the manufacturing process of the photoresist composition as described above, or may be an apparatus mounted on a coating apparatus such as a spinner, a coating and developing apparatus (coater / developer), or the like. Good. That is, in the present invention, the coating apparatus includes not only a so-called photoresist composition coating apparatus but also a comprehensive concept including a coating apparatus integrated with another apparatus such as a developing apparatus, such as a coating and developing apparatus. To do. These coating apparatuses have a nozzle, and normally, a photoresist composition is supplied from the nozzle onto a wafer (substrate), and the photoresist composition is applied onto the wafer.
Therefore, the filtration device of the present invention may be incorporated into the coating device or the like so that the photoresist composition passes through the membrane of the filtration device of the present invention before being supplied onto the wafer from this nozzle. As a result, before the photoresist composition is supplied onto the wafer, those that cause defects in the photoresist composition are removed, so that the effect of reducing defects, particularly fine scum and microbridges, can be obtained. It is done.
In addition, about the specific example of the coating device which mounts the filtration apparatus of the said 3rd, 4th, or 8th invention (mode) which is the said 5th or 9th invention (mode), Example 4-1 mentioned later is mentioned. This will be described in Comparative Example 4-1.

The film used for the first filter 2a is in the range of more than −20 mV and less than 15 mV; preferably in the range of more than −20 mV and less than 10 mV; more preferably in the range of more than −20 mV and less than 10 mV; most preferably negative zeta Those having a potential (exceeding −20 mV) are preferred because they are excellent in defects, in particular, the effect of reducing fine scum and microbridge and the foreign matter aging characteristics.
The negative zeta potential is −5 mV or less (however, over −20 mV), preferably −10 to −18 mV, and more preferably −12 to −16 mV. A filter having a nylon (polyamide) film is particularly preferable as the first filter film, and particularly a filter with a nylon film that satisfies the preferable numerical range of the negative zeta potential.

Of the membranes used for the first filter 2a having such a specific zeta potential, a filter having a membrane showing a positive zeta potential is made of polyamide modified by charge modification (for example, nylon 6 (registered trademark)). ), Nylon 66 (registered trademark, etc.) membranes are generally used.
In addition, as a filter including a membrane exhibiting a negative zeta potential, for example, Ultipore N66 made of nylon 66 (registered trademark) that is not charge-modified (product name: manufactured by Nippon Pole Co., Ltd., the zeta potential is about −12 to − 16 mV), nylon 66 (registered trademark) Ultipleat (registered trademark: P-Nylon Filter) (product name: manufactured by Nippon Pole Co., Ltd., zeta potential is about -12 to -16 mV, pore diameter 0.04 μm), etc. Can be mentioned. Among these, the latter Ultipplez (registered trademark: Ultrapleat) is more preferable.
Further, the filter having a film exhibiting a negative zeta potential is suitable for the method for producing a photoresist composition according to the first, second or seventh invention, and the filtration device according to the third, fourth or eighth invention. Filter.
As a filter in a coating device equipped with the filtration device of the third, fourth or eighth invention which is the fifth or ninth invention, made of nylon 66 (registered trademark) whose attachment / detachment type is changed for the coating device. P-Nyron Filter (product name: manufactured by Nippon Pole Co., Ltd., zeta potential is about −12 to −16 mV, pore size 0.04 μm) and the like. In addition, it is preferable that it is set as the aspect which can remove and replace only a filter in the coating device which mounts the filtration apparatus as a detachable form in a coating device.

  In the present invention, this film-coated filter having a negative zeta potential is preferable because it is excellent in defects, in particular, the effect of reducing fine scum and microbridge and the aging characteristics of foreign matter. The reason for this is not clear, but because it is a membrane filter having a specific zeta potential, specific particles that cause defects and foreign matter aging, particularly lactone groups such as structural units (a2) and (a3) described later, It is presumed that selective filtration efficiency for a resin having a large content of units having a polar group such as a hydroxyl group may be improved. Further, it is preferable to use a film having a negative zeta potential because a photoresist composition in which the sensitivity and the resist pattern size hardly change after the treatment can be obtained even if the photoresist composition is filtered. The reason is presumed that the composition of the composition hardly changes, and for example, a quencher such as a nitrogen-containing organic compound or an organic acid is hardly adsorbed.

The pore diameter of the membrane used for the first filter 2a is the nominal value of the filter manufacturer. It is appropriately adjusted from the viewpoint of productivity and the effect of the present invention, depending on the combination of the filtration sections (combination of filter form, membrane type, number of times of passage through the membrane, etc.).
For example, when only the first filter 2a is used without using the second filter 4a, the pore diameter of the film of the first filter 2a is 0.2 μm or less, preferably 0.1 μm or less, more preferably 0.04 μm. Use of the following products is preferable in terms of effects. However, if it becomes too small, productivity (resist composition production and coating throughput) tends to decrease. The lower limit is about 0.01 μm, but is practically 0.02 μm or more.

Similarly, when filtration is performed in combination with the second filter 4a, it is preferable in terms of effects to use a product of 0.1 μm or less, more preferably 0.04 μm or less. The lower limit is about 0.01 μm, but is practically 0.02 μm or more.
In any case, the defect reducing effect is that the pore diameter of the membrane used for the first filter 2a satisfies the range of 0.01 to 0.04 μm, preferably 0.02 to 0.04 μm. From the point of the effect of improving the foreign matter aging characteristics and productivity, it is preferable. Moreover, 0.04 micrometer is preferable from the point of coexistence of an effect and productivity.
The pore size of the membrane of the second filter 4a is 0.2 μm or less, preferably 0.1 μm or less, more preferably 0.02 μm or less. The lower limit is not particularly limited, but is practically 0.02 μm or more.
Note that the pore diameter of the film used for the second filter 4a preferably satisfies the range of 0.02 to 0.1 [mu] m from the viewpoint of the effect of reducing defects and the effect of improving foreign matter aging characteristics.
The hole diameter of the second filter here is also the nominal value of the filter manufacturer as described above.

As the shapes (forms) of the first filter 2a and the second filter 4a, so-called disk type, cartridge type, and the like are generally used.
The surface area (filtration area) of the first filter 2a and the second filter 4a is preferably adjusted as appropriate depending on the amount of processing of the photoresist composition and the like, and is not particularly limited. .
Further, the filtration pressure [differential pressure resistance] of the first filter 2a and the second filter 4a is not particularly limited, and may be, for example, the same conditions as in the prior art.
The flow rate of the photoresist composition supplied to the first filtration unit 2 and the second filtration unit 4 is appropriately adjusted depending on the filter characteristics, surface area, etc.

  In the first embodiment, by using a film having a specific zeta potential, the effect of reducing defects, particularly fine scum and microbridge, and suppressing foreign matter aging can be obtained. In particular, when a film having a negative zeta potential is used, an effect that a photoresist composition in which changes in sensitivity and resist pattern size hardly occur can be obtained.

Note that the scum and defects of the resist pattern can be evaluated as the number of so-called surface defects by, for example, a surface defect observation apparatus KLA2132 (product name) manufactured by KLA Tencor. The microbridge can be confirmed by observing with a side length SEM or the like.
Foreign matter aging can be evaluated by measuring the number of foreign matters using a particle counter.
As the foreign matter aging characteristics, the foreign matter of the photoresist composition after being stored at 40 ° C. or room temperature after production using, for example, an in-liquid particle counter (manufactured by Rion, product name: particle sensor KS-41 or KL-20K). Evaluate aging characteristics. Such an apparatus counts the number of particles having a particle size of 0.15 to 0.3 μm or more per 1 cm ³ . The measurement limit is usually 20,000 pieces / cm ³ or more.
Normally, the foreign matter in the photoresist composition immediately after production is adjusted to about 10 to 30 particles / cm ³ or less for particles of 0.3 μm or more, and to about 900 particles / cm ³ or less for particles of 0.15 μm or more. ing. By applying the present invention, it is possible to obtain a characteristic that the foreign matter aging characteristic is almost the same as that immediately after manufacturing, preferably even after half a year.

  Whether or not the composition is changed is determined by analyzing the concentration of the material in the photoresist composition before and after the processing through the filter, or when forming a resist pattern using the photoresist composition. Evaluation can be made by measuring changes in sensitivity (optimum exposure amount) and resist pattern size.

Second Embodiment [Operation Procedure and Apparatus]
In the second embodiment, a photoresist composition containing a resin component (A), an acid generator component (B) that generates an acid upon exposure, and an organic solvent (C) has a critical surface tension of 70 dyne / cm or more. And a resin component (A), and an acid generator component (B) that generates an acid by exposure. ) And an organic solvent (C), a filtration unit having a reservoir that stores a photoresist composition, and a first filtration unit that allows the photoresist composition to pass therethrough, wherein the first filtration unit comprises: It is a filtration apparatus characterized by having a 1st filter provided with the 1st film | membrane whose critical surface tension is 70 dyne / cm or more.

The second embodiment is different from the first embodiment in that the first filtration unit 2 shown in FIG. 1 has a first film that satisfies the characteristic that the critical surface tension is 70 dyne / cm or more. The point provided with one filter 2a.
The critical surface tension (physical surface tension) is a physical property known as “wetting property” of the surface physical property of a polymer, and is the surface tension (γc) of a solid. Since γc cannot be directly evaluated like a liquid, it can be obtained from the Young-Dupre equation and Zisman Plot as follows.
Young-Dupre equation:
γLV cos θ = γSV−γSL
In the formula, θ: contact angle, S: solid, L: liquid, V: saturated vapor. When water is used as the liquid, θ is 90 °, and when θ is 90 ° or more, the surface is hydrophobic, and the surface close to 0 ° is called hydrophilic.
Zisman Plot (see Figure 3):
The contact angle θ is measured using various liquids having a surface tension γLV, and γLV and cos θ are plotted. When γLV approaches γSV on the solid surface, θ decreases, and the contact angle θ becomes 0 ° at a certain value of γLV. The γLV of the liquid when θ = 0 ° is defined as the surface tension of the solid, that is, the critical surface tension (γc).
In addition, γc in the polymer material (Material) used for the filter (film processed for the filter) (Medium) and before being used for the filter (before being processed for the filter) is as follows. is there.
-Example of nylon 66 membrane (Medium) provided in the filter: 77 dyne / cm (the unit is omitted below)
General nylon 66 (Material) not provided for the filter: 46
Example of polyethylene or polypropylene membrane (Medium) provided in the filter: 36
Example of polytetrafluoroethylene (PTFE) membrane provided in the filter: 28
-General PTFE (Material) not provided for the filter: 18.5, etc.
Thus, γc differs between the polymer material (Material) and the film (Medium) provided in the filter processed so as to function as a filter.
Γc in the second embodiment means that the critical surface tension of the first film provided in the first filter 2a has a characteristic of 70 dyne / cm or more, and the polymer material (Material) Not a value. This difference results from the processing of the polymeric material (Material) so that it can be included in the filter. Even if the same material is used, the value of the critical surface tension is different if the processing method is different. Therefore, it is preferable that the critical surface tension of the filter film is individually checked for a nominal value or a measured value is obtained.

By using a filter provided with a film having a critical surface tension of 70 dyne / cm or more, the effect of reducing defects, particularly fine scum and microbridge, and suppressing foreign matter aging can be obtained. The upper limit is 95 dyne / cm or less because the defect reduction effect is inferior. A more preferable range is 75 dyne / cm or more and 90 dyne / cm or less, and a further preferable range is 75 dyne / cm or more and 80 dyne / cm or less.
The value of the critical surface tension in the present invention is the nominal value of the manufacturer of the filter. Specifically, a plurality of liquids having known surface tensions are prepared, dropped onto the target film, and soaked into the film by its own weight. It can also be easily determined by identifying the boundaries of things that do not penetrate.

  As the filter satisfying the critical surface tension value in the present invention, the above-mentioned nylon 66 (registered trademark) Ultipleat (registered trademark: P-Nylon Filter) (product name: manufactured by Nippon Pole Co., Ltd., zeta potential is About −12 to −16 mV, pore diameter 0.04 μm, 77 dyne / cm).

On the other hand, examples of the filter that does not satisfy the value of the critical surface tension in the present invention include a filter having a film made of a fluororesin such as PTFE or a polyolefin resin such as polypropylene or polyethylene that has been commercially available.
The value of the critical surface tension of the film in these filters is about 50 dyne / cm or less as described above.
In the second embodiment, a film that satisfies the critical surface tension value and is not subjected to charge modification is preferable. The charge modification is synonymous with the expression of forced potential modification, and the membrane without such charge modification has a specific zeta potential as in the first filter 2a in the first embodiment. I can say that. That is, a range of −20 mV or more and 15 mV or less; preferably a range of −20 mV or more and 10 mV or less; more preferably a range of −20 mV or more and less than 10 mV; most preferably a negative zeta potential (however, more than −20 mV) However, even if the photoresist composition itself is subjected to filtration treatment, it is preferable because a photoresist composition in which changes in sensitivity and resist pattern size hardly occur after the treatment can be obtained. The negative zeta potential is −5 mV or less (however, over −20 mV), preferably −10 to −18 mV, and more preferably −12 to −16 mV.

  About the preferable aspect of the hole diameter of a film | membrane, it is the same as that of 1st Embodiment. In particular, it is preferable to use a product having a pore size of the first filter 2a of 0.04 μm or less. However, if it is too small, productivity (resist composition production and coating throughput) tends to decrease. The lower limit is about 0.01 μm, but is practically 0.02 μm or more.

In the second embodiment, by using a filter including a film having a critical surface tension of 70 dyne / cm or more, an effect of reducing defects, particularly fine scum, microbridge, and foreign matter aging can be obtained.
In particular, by using a film having the above zeta potential, even if the photoresist composition itself is filtered, the composition is less likely to change after the treatment, and the photoresist composition is less susceptible to changes in sensitivity and resist pattern size. Since it is obtained, it is preferable.
The reason for this is not clear, but the critical surface tension is 70 dyne / cm or more, so that the film surface is easily wetted with the resist composition. Therefore, specific particles that cause defects and foreign matter aging, particularly the structural unit (a2 described later) ) And (a3), it is presumed that selective filtration efficiency for a resin having a large content of a unit having a polar group such as a lactone group or a hydroxyl group may be improved.
In addition, it is presumed that by having the zeta potential, the bias of the charge is reduced and the adsorption of a specific substance to the film surface can be suppressed, and as a result, the change in the composition of the photoresist composition can be suppressed. .

Third Embodiment [Operation Procedure and Device]
As a third aspect, a photoresist composition containing a resin component (A), an acid generator component (B) that generates an acid upon exposure, and an organic solvent (C) has a pore size of 0.04 μm or less. A method for producing a photoresist composition comprising a step of passing a first filter having a first film made of a nylon film, a resin component (A), and an acid generator that generates an acid upon exposure A filtration device having a reservoir for storing a photoresist composition containing a component (B) and an organic solvent (C), and a first filtration unit for allowing the photoresist composition to pass therethrough, wherein the first filtration It is a filtration apparatus characterized by having a 1st filter provided with the 1st film | membrane which a part consists of a nylon membrane of 0.04 micrometer or less.

The third embodiment is different from the first embodiment in that the first filter 2 shown in FIG. 1 includes a first filter 2a having a nylon membrane having a pore diameter of 0.04 μm or less. It is a point to use.
As a filter having such a membrane, the above-described nylon 66 (registered trademark) Ultipleat (registered trademark: Ultraplet) P-Nylon Filter (product name: manufactured by Nippon Pole Co., Ltd., zeta potential is about −12 to − 16 mV, pore diameter 0.04 μm, 77 dyne / cm) and the like.
Note that, as described in the second embodiment, the nylon in the filter is the first filter including the first membrane made of the nylon membrane having a pore diameter of 0.04 μm or less in the third embodiment. The membrane naturally does not include general nylon 66 (Material) which is not provided in the filter. Therefore, nylon 66 (Material) which is not provided in the filter having a critical surface tension of 46 dyne / cm does not correspond to the nylon film in the filter.

The pore diameter of the membrane used for the first filter 2a is the nominal value of the filter manufacturer. In the entire embodiment shown in this specification, particularly in this embodiment, the smaller the hole diameter, the more effective the effect of reducing defects and improving the aging characteristics of foreign matter is not simple. It is preferable to select in consideration of the relationship.
For example, even when filtering using only the first filter 2a without using the second filter 4a, or when filtering in combination with the second filter 4a, the pore diameter of the membrane of the first filter 2a is 0.04 μm. Use the following products: If it is too small, productivity (resist composition production and coating throughput) tends to decrease. The lower limit is about 0.01 μm, but is practically 0.02 μm or more. In addition, by being 0.04 micrometer or less, the effect of reduction of a defect, especially the suppression of fine scum, microbridge, and foreign material aging is acquired. In addition, the effect by this numerical limitation is show | played by the combination with the film | membrane made from nylon as mentioned above.

In addition, the preferable aspect in the case of performing combining using the 2nd filter 4a is the same as that of 1st Embodiment.
In the third embodiment, a membrane that satisfies the above requirements and is not subjected to charge modification is preferable. The charge modification is the same as described in the second embodiment, that is, a range of −20 mV or more and 15 mV or less; preferably a range of −20 mV or more and 10 mV or less; more preferably a range of −20 mV or more and less than 10 mV. Most preferably have a negative zeta potential (but greater than -20 mV). Thereby, even if the photoresist composition itself is filtered, a photoresist composition that is less susceptible to changes in sensitivity and resist pattern size after the treatment can be obtained. The negative zeta potential is −5 mV or less (however, over −20 mV), preferably −10 to −18 mV, and more preferably −12 to −16 mV.

By using the first filter including the first film made of a nylon film having a pore diameter of 0.04 μm or less, it is possible to obtain an effect of reducing defects, particularly fine scum, microbridge, and foreign matter aging.
The reason for this is not clear, but due to the fact that it is a nylon membrane and its specific pore size, the membrane surface causes defects and foreign matter, particularly lactone groups such as structural units (a2) and (a3) described later, It is presumed that a resin having a large content of a unit having a polar group such as a hydroxyl group can be selectively adsorbed and the filtration efficiency is improved.

[Photoresist composition suitable for applying the present invention]
The present invention is suitable for the production of a so-called chemically amplified photoresist composition that essentially comprises a resin component (A) and an acid generator (B). That is, the production method of the present invention is suitable for processing a photoresist composition having such a composition, and the filtering device and the coating apparatus of the present invention are suitable for processing a photoresist composition having such a composition.
The component (A) is not particularly limited as long as it is used in a chemically amplified photoresist composition, but is preferably used as a resin component of a photoresist composition for an ArF excimer laser. Examples thereof include a resin having a structural unit derived from an acid ester.
As described above, the fineness after development, which was not a major problem with the resist for KrF excimer laser, particularly when ArF excimer laser or later, that is, when ArF excimer laser, F ₂ excimer laser, EUV, EB, or the like is used as the light source, is used. Therefore, it is preferable to apply the present invention to a process or an apparatus using a resist for these light sources.

-Component (A) As the component (A), an alkali-soluble resin or a resin that can be alkali-soluble is usually used. The former is a so-called negative type photoresist, and the latter is a so-called positive type photoresist composition.
In the case of the negative type, a crosslinking agent is blended in the photoresist composition together with the component (B). When an acid is generated from the component (B) by exposure during the formation of the resist pattern, the acid acts on the cross-linking agent, and the component (A) is cross-linked and becomes alkali-insoluble. As the crosslinking agent, for example, amino-based crosslinking agents such as melamine having a methylol group or alkoxymethyl group, urea or glycoluril are usually used.

  In the case of the positive type, the component (A) is an alkali-insoluble one having a so-called acid dissociable dissolution inhibiting group. When an acid is generated from the component (B) by exposure, the acid dissociates the acid dissociable dissolution inhibiting group. By dissociating, the component (A) becomes alkali-soluble.

In particular, when the present invention is applied to the manufacture of a photoresist composition (particularly positive type) using a resin having a structural unit derived from (meth) acrylic acid ester, the first filter deteriorates defects and foreign matter aging characteristics. The effect of removing foreign substances that cause the occurrence of such a phenomenon is great, which is preferable. In a resin having a structural unit derived from a (meth) acrylic acid ester, it is preferable that the structural unit is 15 mol% or more. In addition, although an upper limit is not specifically limited, 100 mol% may be sufficient.
For reasons that are not clear, such resins contain monomers, oligomers, etc. that have the property of being removed by the first filter as a cause of defects or the cause of foreign matter or an increase in foreign matter over time. It is thought that there is a tendency to.

Specifically, for example, it is preferably used for the production of a positive photoresist composition using a resin containing the following structural unit (a1).
(A1): A structural unit derived from a (meth) acrylic acid ester having an acid dissociable, dissolution inhibiting group.
This resin may optionally further contain the following structural units (a2) and (a3), preferably structural units (a1) and (a2), more preferably (a1), (a2) and (a3). ) Is preferably included.
(A2): A structural unit derived from a (meth) acrylic acid ester having a lactone ring.
(A3): A structural unit derived from a (meth) acrylic acid ester having a hydroxyl group and / or a cyano group.

In the positive photoresist compositions for ArF excimer laser and the following, those containing both the structural units (a1) and (a2) are mainly used. In such a polymer obtained by polymerizing monomers having different polarities, various monomers, oligomers, and other by-products are expected to cause foreign matters such as defects or after a lapse of time. The unit (a1) has a small polarity (high hydrophobicity), and the unit (a2) tends to have a large polarity.
However, by applying the first embodiment, the second embodiment or the third embodiment of the present invention, in a photoresist composition using a resin obtained by polymerizing monomers having different polarities in this way. However, it is possible to improve foreign matter aging characteristics and suppress the occurrence of defects. In particular, in positive photoresist compositions for ArF excimer lasers and later, defects such as fine scum and microbridge are likely to cause problems, and therefore it is effective to apply the present invention.
Moreover, the filter (especially negative zeta) provided with the 1st film | membrane is processed by processing the copolymer which has structural unit (a1)-(a3) or (a1)-(a4) mentioned later by this invention. It is confirmed that a resin having a high content of units having polar groups such as structural units (a2) and (a3) is selectively trapped and removed from the resist composition. Yes.
Such a resin can be synthesized by a conventional method.

..Structural unit (a1)
In the structural unit (a1), the acid dissociable, dissolution inhibiting group is not particularly limited. In general, those formed with a carboxyl group of (meth) acrylic acid and a cyclic or chain tertiary alkyl ester are widely known. Among them, an aliphatic monocyclic or polycyclic group-containing acid dissociable, dissolution inhibiting group can be mentioned, and particularly excellent in dry etching resistance, and from the viewpoint of forming a resist pattern, an aliphatic polycyclic group-containing acid dissociation property. A dissolution inhibiting group is preferably used.
Examples of the monocyclic group include groups obtained by removing one hydrogen atom from cycloalkane and the like.
Examples of the polycyclic group include groups in which one hydrogen atom is removed from bicycloalkane, tricycloalkane, tetracycloalkane and the like.
Specific examples include groups in which one hydrogen atom has been removed from a polycycloalkane such as cyclohexane, adamantane, norbornane, isobornane, tricyclodecane, and tetracyclododecane.
Such polycyclic groups can be appropriately selected and used from among many proposed resin components for resist compositions for ArF excimer lasers, for example.
Of these, an adamantyl group, a norbornyl group, and a tetracyclododecanyl group are industrially preferable.

  More specifically, the structural unit (a1) is preferably at least one selected from the following general formula (I), (II) or (III).

（式中、Ｒは水素原子又はメチル基、Ｒ^１は低級アルキル基である。）

(In the formula, R is a hydrogen atom or a methyl group, and R ¹ is a lower alkyl group.)

（式中、Ｒは水素原子又はメチル基、Ｒ^２及びＲ^３はそれぞれ独立に低級アルキル基である。）

(In the formula, R is a hydrogen atom or a methyl group, and R ² and R ³ are each independently a lower alkyl group.)

（式中、Ｒは水素原子又はメチル基、Ｒ^４は第３級アルキル基である。）

(In the formula, R is a hydrogen atom or a methyl group, and R ⁴ is a tertiary alkyl group.)

In the formula, R ¹ is preferably a lower linear or branched alkyl group having 1 to 5 carbon atoms, such as methyl group, ethyl group, propyl group, isopropyl group, n-butyl group, isobutyl group, pentyl group, An isopentyl group, a neopentyl group, etc. are mentioned. Among them, an alkyl group having 2 or more carbon atoms, preferably 2 to 5 carbon atoms is preferable, and in this case, acid dissociation tends to be higher than in the case of a methyl group. Industrially, a methyl group and an ethyl group are preferable.

R ² and R ³ are each independently preferably a lower alkyl group having 1 to 5 carbon atoms. Such groups tend to be more acid dissociable than 2-methyl-2-adamantyl groups.
More specifically, R ² and R ³ are preferably each independently a lower linear or branched alkyl group similar to R ¹ described above. Among them, the case where R ² and R ³ are both methyl groups is industrially preferable, and specific examples include structural units derived from 2- (1-adamantyl) -2-propyl (meth) acrylate. it can.

R ⁴ is a tertiary alkyl group such as a tert-butyl group or a tert-amyl group, and a case where it is a tert-butyl group is industrially preferable.
In addition, the group —COOR ⁴ may be bonded to the 3 or 4 position of the tetracyclododecanyl group shown in the formula, but since these isomers are mixed, the bonding position cannot be specified. Similarly, the carboxyl group residue of the (meth) acrylate structural unit is bonded to the position 8 or 9 shown in the formula, but the bonding position cannot be specified.
The structural unit (a1) is preferably the above general formula (I) or (II), particularly (I).

  The structural unit (a1) is 20 to 60 mol%, preferably 30 to 50 mol%, based on the total of all the structural units of the component (A).

..Structural unit (a2)
As the structural unit (a2), a structural unit in which a monocyclic group consisting of a lactone ring or a polycyclic group having a lactone ring is bonded to the ester side chain portion of the (meth) acrylic acid ester can be mentioned. At this time, the lactone ring indicates one ring containing an —O—C (O) — structure, and this is counted as the first ring. Therefore, here, in the case of only a lactone ring, it is called a monocyclic group, and when it has another ring structure, it is called a polycyclic group regardless of the structure.
Specific examples of the structural unit (a2) include a monocyclic group obtained by removing one hydrogen atom from γ-butyrolactone, and a polycyclic group obtained by removing one hydrogen atom from a lactone ring-containing polycycloalkane. Formula group etc. are mentioned.
Specifically, for example, structural units represented by the following structural formulas (IV) to (VII) are preferable.

（式中、Ｒは水素原子又はメチル基、ｍは０又は１である。）

(In the formula, R is a hydrogen atom or a methyl group, and m is 0 or 1.)

（式中、Ｒは水素原子又はメチル基である。）

(In the formula, R is a hydrogen atom or a methyl group.)

（式中、Ｒは水素原子又はメチル基である。）

(In the formula, R is a hydrogen atom or a methyl group.)

（式中、Ｒは水素原子又はメチル基である。）

(In the formula, R is a hydrogen atom or a methyl group.)

  The structural unit (a2) is preferably contained in an amount of 20 to 60 mol%, particularly 20 to 50 mol%, based on the total of all the structural units constituting the component (A).

..Structural unit (a3)
As the structural unit (a3), for example, a resin for a photoresist composition for ArF excimer laser can be appropriately selected and used from among many proposed ones. For example, a hydroxyl group and / or a cyano group-containing aliphatic polyvalent compound can be used. It preferably contains a cyclic group, and more preferably contains a hydroxyl group or a cyano group-containing aliphatic polycyclic group.
The polycyclic group can be appropriately selected from a large number of polycyclic groups similar to those exemplified in the description of the structural unit (a1).
Specifically, as the structural unit (a3), those having a hydroxyl group-containing adamantyl group, a cyano group-containing adamantyl group, or a carboxyl group-containing tetracyclododecanyl group are preferably used.
More specifically, a structural unit represented by the following general formula (VIII) can be given.

（式中、Ｒは水素原子又はメチル基である。）

(In the formula, R is a hydrogen atom or a methyl group.)

  The structural unit (a3) is preferably contained in an amount of 10 to 50 mol%, preferably 20 to 40 mol%, based on the total of all the structural units constituting the component (A).

The component (A) may include a structural unit (a4) other than the structural units (a1) to (a3).
The structural unit (a4) is not particularly limited as long as it is another structural unit that is not classified into the structural units (a1) to (a3).
For example, a structural unit containing an aliphatic polycyclic group and derived from a (meth) acrylic acid ester is preferable.
Examples of the polycyclic group include those exemplified in the case of the structural unit (a1), and are for ArF excimer laser, for KrF positive excimer laser (preferably for ArF excimer laser). A large number of hitherto known materials can be used for the resin component of the photoresist composition.
In particular, at least one selected from a tricyclodecanyl group, an adamantyl group, and a tetracyclododecanyl group is preferable in terms of industrial availability.
Specific examples of the structural unit (a4) include those having the following structures (IX) to (XI).

（式中Ｒは水素原子又はメチル基である）

(Wherein R is a hydrogen atom or a methyl group)

（式中Ｒは水素原子又はメチル基である）

(Wherein R is a hydrogen atom or a methyl group)

（式中Ｒは水素原子又はメチル基である）

(Wherein R is a hydrogen atom or a methyl group)

  The structural unit (a4) is preferably contained in an amount of 1 to 25 mol%, preferably 10 to 20 mol%, based on the total of all structural units constituting the component (A).

In addition, although the mass average molecular weight (polystyrene conversion reference | standard by gel permeation chromatography) of resin of (A) component is not specifically limited, it is 5000-30000, More preferably, it is 8000-20000.
Moreover, (A) component can be comprised from 1 type, or 2 or more types of resin, for example, using 1 type or 2 types or more of resin which has a unit induced | guided | derived from the above (meth) acrylic ester. Alternatively, other types of resins may be mixed and used.

-(B) component As (B) component, arbitrary things can be suitably selected from the well-known things as an acid generator in a conventional chemically amplified resist, and can be used.
For example, diphenyliodonium trifluoromethanesulfonate, (4-methoxyphenyl) phenyliodonium trifluoromethanesulfonate, bis (p-tert-butylphenyl) iodonium trifluoromethanesulfonate, triphenylsulfonium trifluoromethanesulfonate, (4-methoxyphenyl) diphenylsulfonium trifluoro L-methanesulfonate, (4-methylphenyl) diphenylsulfonium nonafluorobutanesulfonate, (p-tert-butylphenyl) diphenylsulfonium trifluoromethanesulfonate, diphenyliodonium nonafluorobutanesulfonate, bis (p-tert-butylphenyl) iodonium nonafluorobutane Sulfonate, triphenyl sulfo Including onium salts such as um nonafluorobutanesulfonate can be exemplified. Of these, onium salts having a fluorinated alkyl sulfonate ion as an anion are preferable.

  This (B) component may be used independently and may be used in combination of 2 or more type. The compounding quantity is 0.5-30 mass parts with respect to 100 mass parts of (A) component, for example.

-(C) component (C) component is an organic solvent. As the component (C), any component can be used as long as it can dissolve the component (A) and the component (B) to form a uniform solution. One or two or more can be appropriately selected and used.
Specifically, for example, ketones such as γ-butyrolactone, acetone, methyl ethyl ketone, cyclohexanone, methyl isoamyl ketone, 2-heptanone; ethylene glycol, ethylene glycol monoacetate, diethylene glycol, diethylene glycol monoacetate, propylene glycol, propylene glycol monoacetate , Dipropylene glycol, or dipropylene glycol monoacetate monomethyl ether, monoethyl ether, monopropyl ether, monobutyl ether or monophenyl ether and other polyhydric alcohols and derivatives thereof; cyclic ethers such as dioxane; methyl lactate , Ethyl lactate, methyl acetate, ethyl acetate, butyl acetate, methyl pyruvate, ethyl pyruvate, methoxypropio Methyl acid, esters such as ethyl ethoxypropionate can be exemplified. These organic solvents may be used independently and may be used as 2 or more types of mixed solvents.
Of these, propylene glycol monomethyl ether acetate (PGMEA), ethyl lactate (EL) and the like are preferable. Furthermore, you may mix | blend (gamma) -butyrolactone about 5-20 mass% in (C) component.
The amount of the component (C) is set to a concentration suitable for use as a photoresist composition and applicable to a substrate or the like.

Other components The photoresist composition may further contain other components as desired.
For example, a nitrogen-containing organic compound such as a known amine, preferably a secondary lower aliphatic amine or tertiary lower, is further added as an optional component (D) for improving the resist pattern shape, retention stability and the like. Aliphatic amines can be included.
Here, the lower aliphatic amine means an alkyl or alkyl alcohol amine having 5 or less carbon atoms. Examples of the secondary and tertiary amines include trimethylamine, diethylamine, triethylamine, di-n-propylamine, -N-propylamine, tripentylamine, diethanolamine, triethanolamine and the like can be mentioned, and tertiary alkanolamines such as triethanolamine are particularly preferable.
These may be used alone or in combination of two or more.
(D) component is normally used in 0.01-5.0 mass parts with respect to 100 mass parts of (A) component.

Further, for the purpose of preventing sensitivity deterioration due to the addition of the component (D) and improving the stability of holding, etc., an organic carboxylic acid or an oxo acid of phosphorus or a derivative thereof is further contained as an optional component (E). Can do. In addition, (D) component and (E) component can also be used together, and any 1 type can also be used.
As the organic carboxylic acid, for example, malonic acid, citric acid, malic acid, succinic acid, benzoic acid, salicylic acid and the like are suitable.
Phosphorus oxoacids or derivatives thereof include phosphoric acid, phosphoric acid di-n-butyl ester, phosphoric acid diphenyl ester and other phosphoric acid or derivatives thereof such as phosphonic acid, phosphonic acid dimethyl ester, phosphonic acid- Like phosphonic acids such as di-n-butyl ester, phenylphosphonic acid, phosphonic acid diphenyl ester, phosphonic acid dibenzyl ester and derivatives thereof, phosphinic acids such as phosphinic acid, phenylphosphinic acid and their esters Among these, phosphonic acid is particularly preferable.
(E) A component is used in the ratio of 0.01-5.0 mass parts per 100 mass parts of (A) component.

  In addition, the photoresist composition further contains miscible additives as desired, for example, additional resins for improving the performance of the resist film, surfactants for improving the coating properties, dissolution inhibitors, plasticizers, Stabilizers, colorants, antihalation agents and the like can be added.

A resist pattern using such a photoresist composition can be formed by a conventional method.
For example, the above photoresist composition is first applied onto a substrate such as a silicon wafer with a spinner and prebaked (PAB treatment) for 40 to 120 seconds, preferably 60 to 90 seconds, at a temperature of 80 to 150 ° C. Further, for example, KrF, ArF, or F ₂ excimer laser light, Extreme UV (extreme ultraviolet light), EB (electron beam), or X-ray is selectively exposed through a desired mask pattern by an exposure apparatus or the like. Or after drawing, PEB (post-exposure heating) treatment is performed for 40 to 120 seconds, preferably 60 to 90 seconds under a temperature condition of 80 to 150 ° C. Subsequently, this is developed using an alkali developer, for example, an aqueous solution of 0.1 to 10% by mass of tetramethylammonium hydroxide. In this way, a resist pattern faithful to the mask pattern can be obtained.
An organic or inorganic antireflection film can be provided between the substrate and the coating layer of the resist composition.

Hereinafter, the present invention will be described in detail with reference to examples.
Various physical properties of the photoresist compositions of Examples and Comparative Examples described below were determined as follows.
(1) Foreign matter aging characteristics (Example 1-1) to (Comparative Example 1-2) were stored at 40 ° C after production using an in-liquid particle counter (Rion, product name: KS-41). (6 months, 1 month, or 2 weeks) The foreign material aging characteristics of the photoresist composition were evaluated.
The measurement limit is 20,000 / cm ³ or more.
Further, the foreign matters in the photoresist composition immediately after production were adjusted to 10 particles / cm ³ or less with particles of 0.3 μm or more.
About (Example 2-1)-(Comparative Example 2-3), after storing at room temperature after production using a liquid particle counter (manufactured by Rion, product name: KS-41) (1 month) The foreign material aging characteristics of the photoresist composition were evaluated.
The measurement limit is 20,000 / cm ³ or more.
Further, the foreign matters in the photoresist composition immediately after production were adjusted to 900 particles / cm ³ or less with particles of 0.15 μm or more.

(2) Defect The adjusted photoresist composition (positive type) is applied onto a silicon wafer (diameter 200 mm) using a spinner, pre-baked (PAB treatment) at 130 ° C. for 90 seconds on a hot plate, and dried. A resist layer having a thickness of 350 nm was formed.
Subsequently, ArF excimer laser (193 nm) was selectively irradiated through the mask pattern by an ArF exposure apparatus NSR-S302 (NA (numerical aperture) = 0.60, σ = 0.75 manufactured by Nikon Corporation).
Then, PEB treatment was performed at 120 ° C. for 90 seconds, followed by paddle development with an aqueous 2.38 mass% tetramethylammonium hydroxide solution at 23 ° C. for 60 seconds, followed by washing with water for 20 seconds and drying to obtain a 250 nm line. An and-space pattern was formed (Example 1-2 to Comparative Example 1-2). In Example 2-1 to Comparative Example 2-3, a 130 nm line and space pattern was formed.
Defects were measured using a surface defect observation apparatus KLA2132 (product name) manufactured by KLA Tencor, and the number of defects in the wafer was evaluated. In each of the examples and comparative examples, three wafers were used for the test, and the average value was obtained.
In all the examples and comparative examples, it was confirmed by the side length SEM S-9220 (manufactured by Hitachi, Ltd.) that the defect is a so-called bridge type in which the line pattern is bridged.

(Example 1-1)
The following components (A) to (D) were mixed and dissolved to produce a positive photoresist composition (for ArF excimer laser).

Component (A): The following monomer 2-methyl-2-adamantyl methacrylate 40 mol% (corresponding to the structural unit (a1))
α-gamma butyrolactone methacrylate 40 mol% (corresponding to the structural unit (a2)),
3-hydroxy-1-adamantyl methacrylate 20 mol% (corresponding to the structural unit (a3)),
100 mass parts (B) component: Triphenylsulfonium nonafluorobutane sulfonate 2.0 mass parts (C) Component: PGMEA and EL Mixed solvent (mass ratio 6: 4) 750 parts by mass (D) Component: Triethanolamine 0.2 parts by mass

4000 ml of this photoresist composition is supplied from the storage part to the first filtration part having the following first filter and the second filtration part having the second filter, and sequentially filtered to obtain the photoresist composition. I got a thing. The filtration pressure of the photoresist composition supplied to the first filtration unit and the second filtration unit was 0.4 kgf / cm ² .

First filter: Nylon Ulchipore N66 (product name: manufactured by Paul Corporation)
The first filter has a zeta potential of −15 mV and a pore diameter of 0.04 μm. The specifications are filtration pressure [resistance pressure difference (38 ° C.)] of 4.2 kgf / cm ² , and surface area (filtration area) of 0.2. It was 09 m ² . The filter was a disposable type having a diameter of 72 mm and a height of 114.5 mm. The critical surface tension was 77 dyne / cm.
Second filter: Polypropylene (Product name: Unipore Polyfix, manufactured by KITZ)
The pore size of the second filter was 0.02 μm, and the specifications were filtration pressure [differential pressure resistance (20 ° C.)] of 0.4 MPa and surface area (filtration area) of 3400 cm ² . The filter was a disposable type having a diameter of 58 mm and a height of 148.6 mm. The critical surface tension was 29 dyne / cm.

The foreign matter aging characteristics of the photoresist composition after storage at 40 ° C. for 6 months were almost the same as those immediately after production.
The average number of defects was 10 or less per wafer.
In addition, when what adsorb | sucked to the 1st filter was analyzed, the molar ratio of the said alpha-gamma butyrolactone methacrylate unit and the said 3-hydroxy- 1-adamantyl methacrylate unit among said (a1)-(a3)], The insoluble resin was found to be more than the molar ratio of the original copolymer in the photoresist composition.

(Example 1-2)
In Example 1-1, the same filter as in Example 1-1 was used except that the first filter was changed to a nylon Ultipore N66 (product name: manufactured by Pall) having a pore diameter of 0.02 μm. Thus, the foreign matter aging characteristics and defects were evaluated. The filtration pressure was adjusted according to the filter.
As a result, the foreign matter aging characteristics were almost the same as those immediately after production after one month at 40 ° C. The average number of defects was 10 or less per wafer.

(Example 1-3)
In Example 1-1, the same filter was used as the first filter, and a filter made of polyethylene having the same pore diameter (product name: Macroguard UPE filter, manufactured by Microlith) was used in the second filter. In the same manner as in Example 1-1, foreign matter aging characteristics and defects were evaluated. The filtration pressure was adjusted according to the filter. The critical surface tension of the second filter film was 31 dyne / cm. As a result, the foreign matter aging characteristics were almost the same as those immediately after production after one month at 40 ° C. The average number of defects was 10 or less per wafer.

(Example 1-4) (Reference Example)
In Example 1-1, the same filter was used as the first filter, and the foreign matter aging characteristics and defects were evaluated in the same manner as in Example 1-1 except that the second filter was not used.
As a result, the foreign matter aging characteristics were almost the same as those immediately after production after one month at 40 ° C. The average number of defects was 10 or less per wafer. However, when the same defect was measured after one month at 40 ° C., the average was 20 to 30 per wafer.

(Comparative Example 1-1)
Except that the first filter was changed to the following, a photoresist composition was prepared in the same manner as in Example 1-1, and foreign matter aging characteristics and defects were evaluated.
First filter: Polytetrafluoroethylene (Product name: Enflon, manufactured by Pall)
The first filter has a zeta potential of −20 mV and a pore size of 0.05 μm. The specifications are filtration pressure [differential pressure resistance (38 ° C.)] of 3.5 kgf / cm ² , and surface area (filtration area) is 0. 0.13 m ² and the critical surface tension was 28 dyne / cm. The filter was a disposable type having a diameter of 72 mm and a height of 114.5 mm.

As a result, the aging characteristics of the foreign matter after 2 weeks at 40 ° C. exceeded the measurement limit and could not be measured.
The average number of defects was 5000 per wafer. The length measurement SEM apparatus confirmed that the defect is a so-called bridge type in which the line patterns are bridged.

(Comparative Example 1-2)
In Example 1-1, the same procedure as in Example 1-1 was performed, except that the first filter was a nylon N66 Posidyne (product name: manufactured by Pall Corporation, zeta potential was 18 mV) and the pore diameter was 0.1 μm. The foreign matter aging characteristics were evaluated. The filtration pressure was prepared according to the filter.
As a result, the foreign matter aging characteristics exceeded the measurement limit after 2 weeks at 40 ° C. and could not be measured. The defect did not even need to be measured.

(Example 2-1)
The following components (A) to (D) were mixed and dissolved to produce a positive photoresist composition (for ArF excimer laser).

(A) component: the following monomers 2-methyl-2-adamantyl methacrylate 35 mol% (corresponding to the structural unit (a1): in general formula (I), R and R ¹ are both methyl groups),
α-gamma butyrolactone methacrylate 35 mol% (corresponding to the structural unit (a2): in the general formula (VII), R is a methyl group),
3-hydroxy-1-adamantyl methacrylate 15 mol% (corresponding to the structural unit (a3): in the general formula (VIII), R is a methyl group),
15 mol% of tricyclodecanyl methacrylate (corresponding to the structural unit (a4): in the general formula (IX), R is a methyl group)
100 mass parts (B) component: 2.0 mass parts of triphenylsulfonium nonafluorobutane sulfonate (C) component: 733 mass parts of PGMEA ( Preparation so that the solid content concentration in the composition is 12%)
(D) component: Triethanolamine 0.2 mass part

4000 ml of this photoresist composition was passed through the polytetrafluoroethylene filter used in Comparative Example 1-1, and then pre-filtered through the same second filter as in Example 1-1.
Next, as a first filter, Nylon 66 (registered trademark) Ultiplet (registered trademark) P-Nylon Filter (product name: manufactured by Nippon Pole Co., Ltd., zeta potential of about -12 to -16 mV, pore size 0) .04 μm, with a critical surface tension of 77 dyne / cm).
Such a photoresist composition was evaluated.

There were 14 defects.
The foreign matter aging after storage for 1 month was 982 particles having a particle diameter of 0.15 μm or more.
In addition, when what adsorb | sucked to the 1st filter was analyzed, among the said quaternary unit [(a1)-(a4)], the said alpha-gamma butyrolactone methacrylate unit and the said 3-hydroxy- 1-adamantyl methacrylate unit. It was found to be an insoluble resin having a weight average molecular weight of about 40,000, the molar ratio being greater than the molar ratio of the original copolymer in the photoresist composition.

(Comparative Example 2-1)
After the same prefiltration as in Example 2-1, a photoresist composition was prepared by passing through the polytetrafluoroethylene filter used in Comparative Example 1-1. And it evaluated similarly to Example 2-1.
The number of defects was 4,100.
Foreign matter aging after storage for 1 month was 6509 particles having a particle size of 0.15 μm or more.

(Comparative Example 2-2)
After pre-filtration similar to Example 2-1, a photoresist composition was prepared by passing through a polypropylene filter similar to the second filter used in Example 1-1. And it evaluated similarly to Example 2-1.
There were 34 defects.
The foreign matter aging after storage for 1 month was 1070 particles having a particle diameter of 0.15 μm or more.

(Comparative Example 2-3)
After the prefiltration, except that the pore size of the polypropylene filter used in Comparative Example 2-2 was changed from 0.02 μm to 0.05 μm, the positive photoresist composition was adjusted in the same manner as in Comparative Example 2-2. evaluated. The critical surface tension was the same as that used in Comparative Example 2-2.
There were 244 defects.
As a result of foreign matter aging after storage for 1 month, there were 1030 particles having a particle size of 0.15 μm or more.

(Comparative Example 2-4)
The second filter used in Example 1-1 after the same prefiltration as in Example 2-1, which was made of polyethylene whose pore diameter was changed to 0.05 microns (Product name: Macroguard UPE filter, A photoresist composition was prepared by passing through a filter manufactured by Microlith). And it evaluated similarly to Example 2-1.
There were 897 defects.
Foreign matter aging after storage for 1 month was 1819 particles having a particle size of 0.15 μm or more.

(Example 3-1)
The positive photoresist composition of Example 2-1 was produced in the same composition except that 0.2 parts by mass of salicylic acid was added as the component (E). Subsequently, the prefiltration and the 1st filter were passed similarly to Example 2-1.
Such a photoresist composition was evaluated.

There were about 20 defects.
Foreign matter aging after storage for 1 month was 7 or less particles having a particle diameter of less than 0.20 μm.
Further, this photoresist composition is applied onto a silicon wafer (diameter 200 mm) using a spinner, pre-baked (PAB treatment) at 130 ° C. for 90 seconds on a hot plate, and dried to form a resist layer having a thickness of 400 nm. Formed.
Subsequently, ArF excimer laser (193 nm) was selectively irradiated through the mask pattern by an ArF exposure apparatus NSR-S302 (NA (numerical aperture) = 0.60, σ = 0.75 manufactured by Nikon Corporation).
Then, PEB treatment was performed at 120 ° C. for 90 seconds, and further paddle development was performed with a 2.38 mass% tetramethylammonium hydroxide aqueous solution at 23 ° C. for 60 seconds, followed by washing with water for 20 seconds and drying to form a resist pattern. Formed.
And when the change of the resist pattern size was compared about the thing before and after filtering with a 1st filter, there was no big change in the pattern size of 160 nm.

(Comparative Example 3-1)
In Example 3-1, the N66 Posiddyne made of nylon (product name: manufactured by Pall Corp., zeta potential is 18 mV, critical surface tension is 77 dyne / cm) using the first filter in Comparative Example 1-2 has a pore size of 0. The foreign material aging characteristics were evaluated in the same manner as in Example 3-1, except that the filter was 1 μm.
As a result, the foreign matter aging characteristics exceeded the measurement limit after 2 weeks at 40 ° C. and could not be measured.
The defect did not even need to be measured.
Moreover, when the change of the resist pattern size was compared between before and after filtering with the first filter of this comparative example, the 160 nm pattern size was changed by about 15 nm.

(Example 4-1) (Reference example)
FIG. 2 shows the structure of a photoresist composition coating apparatus equipped with a filtration apparatus used in Example 4-1.
In this example, the positive photoresist composition of Example 2-1 was used. Hereinafter, the apparatus will be described along operation procedures.

The photoresist composition 7 is sucked by the pump 11 from the reservoir tank 10, passes through the introduction tube 9, passes through the first filtration unit 12, and is applied to the substrate 14 such as a silicon wafer from the nozzle 13 of the coating apparatus. Supplied. In addition, this composition is filtered with the 1st filter 12a provided with the 1st film | membrane provided in the 1st filtration part 12. FIG.
The composition after being filtered is dropped from the nozzle 13. At that time, the rotating shaft 17 in the coating unit 18 of the coating apparatus rotates, so that the support unit 15 of the substrate 14 attached to the tip of the rotating shaft 17 rotates the substrate 14 disposed thereon. Then, the photoresist composition dropped on the substrate 14 spreads by the centrifugal force and is applied onto the substrate 14. In addition, the bottomed cylindrical body (defense wall) is provided in the circumference | surroundings of the nozzle 13, the board | substrate 14, and the support part 15 so that these may be enclosed, and the rotating shaft 17 has penetrated the bottom part. The bottomed cylindrical body 16 prevents the photoresist composition from being scattered around by rotating the substrate. Note that the reservoir 8 is provided with a pressurizing tube 6 so that the photoresist composition 7 can be supplied from the reservoir 8 to the reservoir tank 10 by pressurizing the photoresist composition 7 with an inert gas such as nitrogen. ing.

The reservoir tank 10 may or may not be provided, and the pump 11 is not limited as long as it has a function of supplying photoresist from the storage unit 8 to the application unit 18.
In addition, the 2nd filtration part provided with the 2nd filter can also be provided in one or both before and behind the 1st filtration part 12, and the combination of filters is various as mentioned above demonstrated about the filtration apparatus. Embodiments can be selected.
Although the example of the spinner is shown as the coating apparatus, in recent years, various coating methods other than the spin coating such as the slit nozzle method have been proposed, and the apparatus has also been proposed.
Further, as described above, the coating apparatus may be a so-called coating / developing apparatus that can consistently perform subsequent development processes. For example, “Clean Truck ACT-8” manufactured by Tokyo Electron Ltd. can be used, and this was used in this example.

The first filtration unit 12 is the first filter including the first membrane having a zeta potential of more than −20 mV and 15 mV or less in distilled water having a pH of 7.0 in the third invention, or in the fourth invention. A portion having the first filter provided with the first film having a critical surface tension of 70 dyne / cm or more, or the first filter comprising the nylon film of 0.04 μm or less in the eighth invention It is. In addition, as this filter, for example, P-Nyron (product name: manufactured by Nippon Pole Co., Ltd., having a membrane made of nylon 66 (registered trademark), the zeta potential is about −12 to −16 mV, the pore diameter is 0.04 μm, critical The surface tension can be 77 dyne / cm), etc., which was used in this example.

  According to this apparatus, a positive resist layer is formed on the substrate 14 by the series of processes described above using the positive photoresist composition of Example 2-1. Thereafter, a resist pattern is formed by pre-baking, selective exposure, PEB, development, and rinsing along a normal lithography process. Then, the formed resist pattern is measured using a surface defect observation apparatus KLA2132 (product name) manufactured by KLA Tencor Co., Ltd., and defects in the wafer are evaluated.

Note that the second filter described in the first, second, third, fourth, seventh, and eighth inventions may be used as necessary.
In this example, the lithography process was performed as follows.
Example 2-1 A positive photoresist composition was applied on a silicon wafer (diameter 200 mm) using a spinner, pre-baked (PAB treatment) at 130 ° C. for 90 seconds on a hot plate, and dried to obtain a film thickness. A 350 nm resist layer was formed. Subsequently, ArF excimer laser (193 nm) was selectively irradiated through the mask pattern by an ArF exposure apparatus NSR-S302 (NA (numerical aperture) = 0.60, σ = 0.75 manufactured by Nikon Corporation). Then, PEB treatment was performed at 120 ° C. for 90 seconds, and further paddle development was performed for 60 seconds with an aqueous 2.38 mass% tetramethylammonium hydroxide solution at 23 ° C., followed by washing with water for 20 seconds and drying, and a 130 nm line. An and space pattern was formed.
When the defects on the pattern were measured with the KLA2132, the number of defects was 14, which was a very good result.

(Comparative Example 4-1)
In Example 4-1, the first filter was the same as Example 4-1, except that the first filter was changed to the one made of polytetrafluoroethylene used in Comparative Example 1-1 (product name: Enflon, manufactured by Paul). Then, the photoresist composition was prepared and the defect was evaluated.
As a result, when the number of defects on the pattern was measured, it was 4100, which was a bad result.

(Comparative Example 4-2)
In Example 4-1, the first filter used in the second filter of Example 1-1 was made of polypropylene (product name: Unipore Polyfix, manufactured by KITZ, Inc., pore diameter: 0.02 μm). Except for the change, a photoresist composition was prepared in the same manner as in Example 4-1, and the defect was evaluated.
As a result, when the number of defects on the pattern was measured, it was 34, which was a poor result.

(Comparative Example 4-3)
In Example 4-1, the first filter was made of the same polypropylene as used in Comparative Example 2-3 except that the filter had a pore diameter of 0.05 μm. A photoresist composition was prepared in the same manner as in 4-1, and the defect was evaluated.
As a result, when the number of defects on the pattern was measured, it was 244, which was a bad result.

(Comparative Example 4-4)
In Example 4-1, the first filter is made of the same material as that used in Example 1-3 as the second filter, but the hole diameter is changed to 0.05 μm, and the most versatile application device. A photoresist composition was prepared and defects were evaluated in the same manner as in Example 4-1, except that a polyethylene filter (product name: Macroguard UPE filter, manufactured by Microlith) was used.
As a result, when the number of defects on the pattern was measured, it was 897, which was a bad result.

From the results of the above examples and comparative examples, it was found that in the examples according to the present invention, the foreign matter aging characteristics are remarkably improved only by changing the filter film type.
It was confirmed that the fine scum and microbridge at the time of forming the resist pattern can be significantly reduced. Moreover, there was no change in the characteristics before and after filtration, which was good.

DESCRIPTION OF SYMBOLS 1 ... Stock solution storage tank, 2 ... 1st filtration part, 2a ... 1st filter, 4 ... 2nd filtration part, 4a ... 2nd filter, 5 ... Container, 6 ... Pressure tube, 7 ... Photoresist, 8 ... Photoresist reservoir, 9 ... Photoresist introduction tube, 10 ... Reservoir tank, 11 ... Pump, 12 .... 1st filter part, 12a ... film, 13 ... nozzle for dripping photoresist, 14 ... substrate such as silicon wafer, 15 ... substrate support, 16 ... bottomed cylindrical shape Body, 17... Rotating shaft, 18.

Claims (3)

A structural unit (a1) derived from a (meth) acrylic acid ester having an acid dissociable, dissolution inhibiting group, a structural unit (a2) derived from a (meth) acrylic acid ester having a lactone ring, a hydroxyl group and / or A resin component (A) having a structural unit (a3) derived from a (meth) acrylic acid ester having a cyano group, an acid generator component (B) that generates an acid upon exposure, and an organic solvent (C). Before and after the step of passing the first filter, the step of passing a first filter comprising a first membrane made of a nylon membrane having a pore diameter of 0.04 μm or less. One or both of the steps further comprises passing the photoresist composition through a second filter having a second film made of polyolefin resin or fluororesin. Method for producing Torejisuto composition.   The method for producing a photoresist composition according to claim 1, wherein the second film is made of polyethylene, polypropylene, or PTFE (polytetrafluoroethylene). The structural unit (a1) is 20 to 60 mol%, the structural unit (a2) is 20 to 60 mol%, and the structural unit (a1) is based on the total of all structural units of the resin component (A). The method for producing a photoresist composition according to claim 1 or 2, wherein a3) is from 10 to 50 mol%.

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