JPH05234876A - Method for removing metal impurity from resist component - Google Patents

Abstract

PURPOSE: To remove metal impurities from a resist component by allowing a resist component solution to make sufficient contact to a cation exchange resin and a chelate resin. CONSTITUTION: In a solvent, preferably a mixture liquid of ethyl lactate and ethyl-3-ethoxypropionte, a resist component for example a novolak resin is dissolved. Then the solution is put in a plastic bottle, and then a chelate resin and a cation exchange resin are added. Both the chelate resin and the cation resin are washed three times in ethyl lactate before being used. The obtained suspension is rotated for 24 hours in a bottle rotator. Then, the suspension is filtered with a membrane filter, so that resist components such as containing no metal impurities is obtained.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a method for removing metallic impurities from resist components. More specifically, the present invention removes metal impurities (including sodium, iron, calcium, chromium, copper, nickel, zinc, etc.) from the resist component or the solution of the resist composition. It relates to a method comprising contacting with a chelating resin.

[0002]

BACKGROUND OF THE INVENTION Photoresist compositions have been used in microlithographic processes for the fabrication of miniaturized electronic components, such as in the manufacture of integrated circuits and printed wiring board circuits. Generally, in these methods, a thin coating or film of a photoresist composition is first applied to a silicon wafer used to make integrated circuits, or a substrate material such as an aluminum or copper plate for printed wiring boards. The coated substrate is then baked to evaporate the solvent in the photoresist composition and fix the coating on the substrate.

The coated surface of the baked substrate is then subjected to imagewise radiation exposure. This radiation exposure causes a chemical transformation in the exposed areas of the coated surface. Visible light, ultraviolet (UV) light, electron beams, and X-ray radiant energy are the types of radiation currently commonly used in microlithography. After this imagewise exposure, the coated substrate is treated with a developer to dissolve and remove either the radiation-exposed or unexposed areas of the substrate-coated surface.

There are two types of photoresist compositions, negative acting and positive acting. Both negative-acting and positive-acting compositions are generally made up of a film-forming resin and a photoactive compound dissolved in a suitable coating solvent. Additives for specific functions can be added. When a negative-acting photoresist composition is imagewise exposed to radiation, the areas of the resist composition that are exposed to radiation become less soluble in the developer (eg, due to a crosslinking reaction), while the photoresist is exposed. The unexposed areas of the coating remain relatively soluble in the developer. Therefore, treatment of the exposed negative working resist with a developer will result in the removal of the unexposed areas of the resist coating, thus producing a negative image in the resist coating; and thereby the photoresist composition being deposited. The desired portion of the side substrate surface is removed.

On the other hand, when a positive-acting photoresist composition is imagewise exposed to radiation, the areas of the resist composition exposed to radiation become more soluble in the developer (eg, intramolecular transfer reactions occur. Areas that were not exposed at the same time remain relatively insoluble in the developer. Accordingly, treatment of the exposed positive working resist with a developer removes the exposed areas of the resist coating, producing a positive image in the photoresist coating. The desired portion of the underlying substrate surface is stripped.

After this development step, the now partially unprotected substrate is treated with a substrate etchant, plasma gas, or the like. This etchant or plasma gas etches the portion of the substrate where the photoresist coating has been removed in the developer. The areas of the substrate where the photoresist coating still remains are protected and the pattern thus etched forms in the substrate material corresponding to the photomask used for the imagewise exposure of the radiation. The remaining areas of the photoresist coating can then be removed by a stripping process, leaving a clean etched substrate surface. In some cases it is desirable to heat treat the remaining resist layer after the development step and before the etching step to increase adhesion to the underlying substrate and resistance to the etchant.

Positive-acting photoresist compositions are currently preferred because they generally have better resolution and pattern transfer characteristics than negative-acting photoresist compositions. Preferred positive acting photoresists generally comprise a novolak resin and an o-quinonediazide photoactive compound dissolved in a suitable solvent.

Impurity levels in photoresist compositions have become of increasing concern. Contamination of photoresist impurities, especially metals, can lead to deterioration of semiconductor devices made by the photoresist, shortening the life of these devices.

The level of impurities in the photoresist composition is (1) the selection of materials for the photoresist composition that meet strict impurity level specifications, and (2) the introduction of impurities into the photoresist composition, so that the photoresist formulation And has been and is being controlled by careful management of process parameters. As photoresist applications continue to grow. More stringent impurity standards have to be created.

When novolac resin materials are used to make positive photoresists, such novolac resins have been subjected to distillation or recrystallization purification steps to remove impurities, especially metals. However, such a process has drawbacks. First, it is time consuming and costly. More importantly, these require impurities to a very low level now required for advanced applications (ie ppb at the highest level).
Lower value) and cannot be removed.

Alternatively, ion exchange resins have been used for novolac impurities. One common method is to pass an impure novolac resin solution through a granular cation exchange resin (eg, AMBERLYST styrene sulfonic acid-divinylbenzene cation exchange resin). However, such a process has some problems associated with it, including the following:

1. Cation exchange resin treatment of novolaks will reduce the pH value of the novolac-containing solution and will likely result in significant corrosion of the metal container for storing the purified novolac-containing solution.

2. Although purified novolaks may have a reduced dissolution rate during the photoresist development process,
This may be due to the undesirable adsorption of the low molecular weight portion of the novolak resin on the cation exchange resin.

3. Alkali metals such as sodium and potassium are easily removed by conventional particulate cation exchange resins. However, divalent or trivalent metal cations (eg Cu ⁺² , Ni ⁺² , Zn ⁺² , Fe ⁺² , F
e ⁺³ , Ca ⁺² or Cr ⁺³ ions) have a low affinity for common cation exchange resins. Iron and other easily oxidizable metals cannot be completely removed as they can become colloidal metal oxides or hydroxides. Such a colloidal substance is not significantly removed by the cation exchange resin treatment.

4. Ion exchange resins, especially strong acid type cation exchange resins, decompose resist components or solvents used which contain hydrolyzable groups such as esters. For example, ethyl lactate decomposes by Amberlyst A-15 to form a polylactite moiety, impairing the lithographic performance of the photoresist. As used herein, the term “polylactite” refers to a cyclic dimer of lactic acid (lactic acid) produced by hydrolysis of ethyl lactate, a polymer or oligomer product of lactite, and the like.

In addition to standard cation exchange resin treatments of novolac resins, complete photoresist compositions (eg, novolac resins, photosensitizers, and solvents) can be subjected to both cation and anion exchange resin treatments. Are known. For example, Japanese Patent Publication No. Sho 57-743.
No. 70 shows a method of reducing impurities in a resist by using a cation exchange resin and an anion exchange resin separately and sequentially. September 12, 1989
Published Japanese Patent Publication No. 1-228,56
No. 0 shows that the content of metal impurities in the photosensitive resin solution or photoresist composition can be reduced by a mixture of cation and anion exchange resins. However, both of these methods have the drawback that they cannot remove divalent and trivalent metal impurities and may decompose the solvent for the resist components or resist composition.

Usually, such cation and anion exchange resins are washed with deionized water or a solvent similar to the solvent in which the resist components are dissolved. However, metal ions such as sodium or potassium, as well as other acidic contaminants, are strongly bound to the anionically charged groups of the cation exchange resin, so such washing with water or solvent does not result in metal impurities. Cannot clean the resin that has already adhered.

Accordingly, there remains a need in the photoresist art for improved methods of removing metallic impurities from novolac resins and other materials used as photoresist components. The present invention is one answer to this need.

[0019]

Accordingly, one embodiment of the present invention is to remove metal impurities from the resist component: (a) dissolving the resist component in a solvent; (b) adding the cation exchange resin and the chelate resin to the resist component solution. At least a portion of the metal impurities on the cation exchange and chelate resins; and (c) separating the cation exchange and chelate resins carrying the metal impurities from the resist component solution. The present invention is directed to a method for removing metal impurities, which comprises each step of

A preferred embodiment of the present invention is to remove metal impurities from the resist component: (a) dissolving the resist component in a solvent; (b) allowing the resist component solution to cation exchange resin and chelate resin for sufficient time. Contacting to adsorb at least a portion of the metal impurities on the cation exchange and chelate resin, wherein the cation exchange resin, and optionally the chelate resin, was pre-washed with a solution of a quaternary ammonium salt compound. And (c) a method for removing metal impurities, which comprises the steps of: (c) separating the cation exchange supporting the metal impurities and the chelate resin from the resist component solution.

[0021]

DETAILED DESCRIPTION OF THE INVENTION The term "resist component" used in the present specification and claims includes an alkali-soluble resin such as a novolak resin and a polyvinylphenyl resin, a photoactive compound and its precursor and photoresist compositions. Each additive (for example, a sensitivity enhancer, a dye, etc.) usually used in the product is included. The term also includes precursor compounds for making each such component. Examples of such precursor compounds are bone nucleus compounds for making photoactive compounds, as well as photoactive ester compound precursors (eg naphthoquinone diazide sulfonyl chloride) and the like.

As used herein, the term "novolak resin" refers to
It refers to any of the novolak resins that are completely soluble in alkaline developers that are commonly used for positive acting photoresist compositions. Suitable novolac resins include phenol-formaldehyde novolac resin, cresol-formaldehyde novolac resin,
Included are those having a molecular weight of preferably about 500 to about 40,000, more preferably about 800 to about 20,000, such as xylenol-formaldehyde novolac resin, cresol-xylenol-formaldehyde novolac resin.

These novolac resins are preferably made by addition-condensation polymerization with a phenolic monomer or monomers (eg phenol, cresol, xylenol or mixtures thereof) together with a source of aldehydes such as formaldehyde, It is stable, water-insoluble, alkali-soluble, and has film-forming properties. One preferred novolak resin is about 1,0 produced by polycondensation between a mixture of meta- and para-cresol and formaldehyde.
It has a molecular weight of 00 to about 10,000. Representative novolak resin production processes are shown in US Pat. Nos. 4,377,631; 4,529,682; and 4,587,196 issued to Medhat Toukhy. Has been done.

Another preferred novolak resin is 199
PCT Publication WO 91/0, published March 21, 1
No. 3769.

The term "photoactive compound" as used herein and in the claims includes any of the conventional photoactive compounds commonly used in photoresist compositions. The quinonediazide compounds as a generic concept are one of the preferred classes of compounds, of which the preferred class of classes are the naphthoquinonediazide compounds. As mentioned previously, photoactive compound precursors can also be treated according to the present invention. One of the photoactive compound precursors handled by this method is 2,6-bis (2,3,4-trihydroxyphenyl) methylene-4.
-Methylphenol (this product is also known as 7-PyOL), which is described in U.S. Pat. No. 4,992,3.
No. 56, Example 3.

Photoresist additives can be handled according to the present invention. Such additives include sensitivity enhancers,
Includes pigments, etc. The preferred sensitivity enhancer is 1
-[(1'-methyl-1 '-(4'-hydroxyphenyl) -ethyl)] 4- [1', 1'-bis- (4-hydroxyphenyl) ethyl] benzene (this is TRI
(Known as SP-PA).

In the first step of the method of the present invention, the resist component is dissolved in a solvent or solvent mixture to facilitate contact of the resist component with the cation exchange resin and the chelate resin. Examples of suitable solvents are acetone, methoxyacetoxypropane, ethyl cellosolve acetate, n-
Butyl acetate, ethyl lactate, ethyl-3-ethoxypropionate, propylene glycol, alkyl ether acetate or mixtures thereof, and the like. Cosolvents such as xylene or n-butyl acetate can also be used. One preferred solvent is a mixture of ethyl lactate and ethyl-3-ethoxypropionate, wherein the weight ratio of ethyl lactate: ethyl-3-ethoxypropionate is about 30: 7.
0 to about 80:20.

The solid content of the resulting resist component solution is not critical. Preferably, the amount of solvent or solvent mixture is from about 50% to about 500% by weight or more; more preferably from about 75% to about 400% by weight based on the weight of the resist component.

Although it is preferred to use a single resist component as the material treated by the method of the present invention, it is contemplated that combinations of resist components may be used within the scope of the present invention. For example, in accordance with the present invention, a fully positive acting photoresist formulation (eg, novolak resin or resins, photoactive compounds such as quinonediazide sensitizers and dyes, sensitivity enhancers, surfactants as well as solvents or mixed solvents). , A combination of conventional optional minor components such as, etc.) may be desired.

Metallic impurities in the solution of the resist component are monovalent metal cations such as alkali metals (that is, Na ⁺ and K ⁺ ) and divalent or trivalent cations (that is, Ca).
⁺² , Fe ⁺² , Fe ⁺³ , Cr ⁺³ or Zn ⁺² ). Such metallic impurities may also be present in the form of colloidal particles, such as insoluble colloidal iron hydroxides and oxides. This metallic impurity may come from the chemical precursors for the resist components (ie in the case of novolac resins this is the phenolic monomer and the aldehyde source) as well as the solvent used to make the solution. These impurities may also come from the catalyst used to make the resist component, or the equipment used to synthesize or store it.

Generally, the amount of metal impurities in resist components such as novolac resins will be 500 by weight for metals such as sodium and iron prior to applying the method of the present invention.
Up to 5,000 ppb, or more. Sodium impurities are generally in the form of monovalent ions (Na ⁺² ). Iron impurities are generally present in the form of divalent and trivalent (Fe ⁺² and Fe ⁺³ ) and also in the form of insoluble colloidal iron (ie iron hydroxides and oxides).

The resist component solution is prepared by the conventional method of mixing a solvent and a resist component. Generally, it is preferable to add the resist component to a sufficient amount of the solvent and dissolve the resist component in the solvent. This process is facilitated by agitation or other conventional mixing means.

The next step in the method of the present invention is to contact the solution of the resist component with at least one chelate resin and at least one cation exchange resin.

Chelating resins useful for the present invention include:
Included are any of the chelate resins compatible with the cation exchange resin used as well as the solvent of the resist component, while being capable of removing metals from the resist component. Examples of suitable chelating resins include iminodicarboxylic acid-derivatized poly (chloromethylstyrene),
Included are 2,5-dihydroxyterephthalaldehyde-diamine Schiff salt polyacrylates, and polyhydroxamic acids derived from polyacrylates and hydroxylamines, beta-diketone polymers, polyphosphoric acids, polyamines, and the like. One preferred chelating resin is Dowex available from Dow Chemical Company.
EX) A-1. This is an iminodicarboxylic acid type resin.

Another preferred chelating resin is DIAION (DIA) manufactured by Mitsubishi Kasei Co., Ltd. of Japan.
NION) CR-20. The chelating resin is a cross-linked styrene-divinylbenzene copolymer resin having polyamine functional chelating groups in the copolymer and having an average particle size of 1.2 μm.

Addition of a chelate resin having polyamine chelate groups to the resist component increases the pH value of the resulting mixture (ie, from about 3.5 to about 5-6 in proportion to the amount of chelate resin added). ) Was recognized. This unexpected increase in pH value causes the formation of hydroxide complexes for ferric or other polyvalent metal ion impurities. These hydroxide complexes precipitate from the liquid and can be removed by conventional separation means (ie microfiltration). The treatment with the polyamine-type chelate resin reduces the pH value of the resist component solution because the treatment with the cation exchange resin reduces the pH value.
The pH of the resist component solution will generally be returned to its original pH level. Therefore, the adverse corrosion and other undesired effects associated with highly acidic materials will be avoided.

Cation exchange resins useful for the present invention include any and all cation exchange resins that are capable of removing metal from the resist component and that are compatible with the chelate resin used with the solvent of the resist component. Be done. Suitable cation exchange resins include phenol sulfonate-formaldehyde condensates, phenol-benzaldehyde sulfonate condensates, styrene sulfonic acid-divinylbenzene copolymers, acrylic acid-divinylbenzene copolymers, methacrylic acid-divinylbenzene copolymers and other types of sulfonic acid. Alternatively, polymers containing a carboxylic acid group are included. One preferred particulate cation exchange resin is Amberlyst 15 available from Rohm and Haas. This is a styrene sulfonic acid-divinylbenzene copolymer.

Besides granular cation exchange resins, fibrous cation exchange resins can also be used. The term "fiber-like" is used to describe ion exchange resins, especially cation exchange resins, which have been made into fiber materials as opposed to particulate materials. Such a fibrous material may be in the form of fibrous, sheet, chordal, fine fibrous, fine film or the like. The fibrous resin can be made from organic ion exchange resin materials in which ion exchange groups have been introduced onto the resin such as polystyrene, polyphenols, polyvinyl alcohol, polyacrylates, polyesters and polyamides. The fibrous ion-exchange resin can also be composed of a mixture of the above-mentioned ion-exchange resin materials with non-ion-exchange resins or fibrous materials such as polyolefin resins, acrylonitrile polymers and copolymers and cellulose acetate.

Generally, the fibrous ion-exchange resin has a diameter of about 1 to 500 μm, preferably 10 to 100 μm and a length of about 0.1 to 100 μm, preferably 0.50 to 50 m.
It is made in the shape of m. A preferred fibrous cation exchange resin is TIN-available from Toray Industries, Inc. of Japan.
100 and TIN-600. TIN-100 has a sulfonic acid exchange group introduced on a polystyrene resin,
It is a polystyrene / polyolefin composite fiber. TI
N-600 is a polystyrene / polyolefin resin in which an iminodiacetic acid exchange group is introduced on polystyrene. 40 μm for both TIN-100 and TIN-600
It has a diameter of 0.5 mm and a length of 0.5 mm. These fiber-like ion exchange resins have excellent adsorption power and large surface area, and at the same time have good chemical resistance and heat resistance.

The amounts of the chelate resin and the cation exchange resin used in the method of the present invention are preferably about 1% by weight to about 10% by weight based on the solution of the resist component. More preferably, these amounts are from about 2% to about 4% by weight, based on the solution.

The chelate resin: cation exchange resin weight ratio used in the method of the present invention is generally from about 9: 1 to about 1: 1.
9, more preferably about 75:25 to about 25:75, and most preferably about 1: 1.

As previously explained, another embodiment of the present invention is the pretreatment or prewash of the cation exchange resin, optionally the chelate resin, with a quaternary ammonium salt solution. This quaternary ammonium cation can enhance the ion exchange reaction between the prewashed cation exchange resin or chelate resin and the resist component without undesirably reducing the pH value of the treated resist component. Admitted.

The anions in the quaternary ammonium salt compound, especially the hydroxyl groups, can extract the cationic counterion of the cation exchange resin (that is, H ⁺ or Na ⁺ ), so that the bulky quaternary ammonium cation is the cation. It seems to be a counter ion on the exchange resin. This bulky quaternary ammonium cation counterion substitution with H ⁺ or Na ⁺ cation counterions results in high efficiency of metal ion reduction and suppression of hydrolysis of the resist component or solvent containing the resist component. Give birth.

Quaternary ammonium salt compounds include tetramethylammonium hydroxide (TMAH), although other classes of quaternary ammonium salts as well as other tetra-alkylammonium hydroxides are suitable for the process of this invention. Will. Other quaternary ammonium cations include tetraethylammonium, methyltriethanolammonium, benzylmethyldiethanolammonium, and the like.

The most preferred quaternary ammonium salt compounds are polymeric quaternary ammonium compounds.
These include hexamethrine, poly (vinylbenzyltrimethylammonium) chloride, polyimidazoline and quaternized poly (vinylpyridine).

Polymeric quaternary ammonium compounds are preferred because their cations are more strongly immobilizable to the anionic groups of the cation exchange resin than the monomeric quaternary ammonium cations.

The quaternary ammonium salt is contacted with the ion exchange resin in the form of a solution, preferably an aqueous solution. The amount of ammonium salt in the solution is generally about 1 to about 50.
% By weight.

The amount of quaternary ammonium salt compound used should be in excess relative to the weight of the cation exchange and chelating resin treated. Fourth commonly used
The amount of primary ammonium salt is about 150 to 1,000 weight percent or more of the cation exchange and chelate resin.

The prewashing method may be any of the methods conventionally used for washing cation exchange and chelating resins with water or organic solvents. One preferred method is to add the resin to a large excess of an aqueous solution containing 2 to 30% by weight of quaternary ammonium salt, and to add 20
Stir the resulting suspension for ˜40 minutes and then decant the quaternary ammonium salt solution. It is preferable to repeat this stirring and inclining 3 to 5 times. Thus, the washed resin can be further washed with the same solvent liquid,
It will be used in the contacting step (b) to pre-swell the cation exchange and chelating resins.

The chelate resin and the cation exchange resin can be brought into contact with the solution of the resist component by simultaneous or sequential operations. At the same time, the contact between the chelating resin and the cation exchange resin will occur simultaneously. If sequential, the resist component is first contacted with either the chelate resin or the cation exchange resin and then with the other resin. In each case, the time for each contact is at least a portion (preferably at least a majority ... at least 50% by weight ...) Of the metal impurities present in the resist component solution and more preferably at least 90
% By weight) should be sufficient to adsorb.

There are four preferred modes of this contacting process for the present invention. These are as follows:

1. Mixed bed column system-the chelate resin and the cation exchange resin are packed together in an ion exchange column and the solution of resist components is passed through this column. Preferably, the resist component solution is passed at a constant rate and temperature to maximize adsorption of metal impurities on the chelate and cation exchange resin.

2. Mixed batch system-A chelate resin and a cation exchange resin are mixed in a resist component solution to form a suspension. After sufficient contact time, the chelate and cation exchange resin are removed from the resist component solution, preferably by filtration. Preferably, it may be advantageous if the chelating resin and the cation exchange resin may be dispersed in the solvent prior to addition to the resist component solution. Further, contact in this manner is preferably carried out at a constant temperature to maximize adsorption on the chelate and cation exchange resin.

3. Sequential column system-the chelate resin is packed in one ion exchange column and the cation exchange resin is packed in another ion exchange cation. A solution of resist components is passed sequentially through the two columns.

4. Sequential batch system-In this method, a solution of the resist component is mixed with either the chelate resin or the cation exchange resin in a closed container and, after a suitable contact time, the chelate resin or the cation exchange resin is removed from the resist component solution. , Preferably by membrane filtration. The partially treated resist component solution is then contacted with the resin that was not used initially, and the resin is then separated by the resist component solution.

The separation step (c) of the present invention, when a mixed bed column system or a sequential column system is used,
Occurs immediately after the contacting step (b). In mixed batch systems and sequential batch systems, this separation step (c) requires additional operator intervention.

After the contact and separation steps, the resist component system thus treated has a reduced metal content of less than about 100 ppb (weight). For example, the amount by weight of sodium and iron impurities is only 100-20 pp each.
It is in the range of b or even less.

The resist component solution is preferably contacted with other optional materials besides the chelate resin and the cation exchange resin. One preferred optional material is an anion exchange resin. Such resins can be used when there is the problem of concomitant pH drop or insufficient removal of metal. Suitable anion exchange resins include quaternary ammonium group-containing phenolic resins, quaternary ammonium group-containing styrene-divinylbenzene copolymers, aromatic polyamines, polyethyleneimine and the like.

One preferred particulate anion exchange resin is a quaternary ammonium styrene-designated Amberlyst A-27 manufactured by Rohm and Haas.
It is a divinylbenzene resin. Another preferred granular anion exchange resin is a fatty amino group-containing styrene-divinylbenzene resin called Amberlyst A-21, also made by Rohm and Haas. In addition, a fiber-shaped anion exchange resin can also be used. Such resins have anion exchange groups such as primary amines, secondary amines, tertiary amines, quaternary ammonium salts, and others. One of the fiber-like anion exchange resins is TI available from Toray Industries, Inc. of Japan.
N-100. This is a polystyrene / polyolefin composite resin having trimethylammonium groups introduced onto polystyrene.

If the untreated resist component solution contains a significant amount of insoluble colloidal hydroxides or oxides, the resist component solution is added to the cation exchange resin and the chelate resin prior to contact with the solution. Pass through a micropore membrane with a pore size of 1-0.5 μm. This filtration operation will remove at least a portion of the insoluble colloid, making the contacting step (b) more efficient.

The following examples and comparative examples are provided to further illustrate the present invention. All parts and percentages are by weight unless otherwise stated.

Example 1 A meta / para mixed cresol novolak resin was made by reacting formaldehyde with a cresol mixture of 40 mol% m-cresol / 60 mol% p-cresol. The molecular weight of this novolac resin is 6,50 as measured by GPC.
It was 0. This novolak (44.8 g) was dissolved in a mixed solvent of ethyl lactate (EL, 90.0 g) and ethyl-3-ethoxypropionate (EEP, 38.6 g). Next, this novolak solution was put into a plastic bottle, and the chelate resin ⁽¹⁾ (3.5 g) and the cation exchange resin ⁽²⁾ (3.5 g) were added to this bottle.
Both the chelate resin and the cation exchange resin were washed 3 times with ethyl lactate before use.

The resulting suspension was rotated in a bottle rotator for 24 hours. The chelates and cation exchange resin particles were removed from the suspension by filtering the suspension through a membrane filter having a pore size of 0.2 μm (size.

The content of sodium and iron impurities in this novolak solution was measured before adding the chelate and the cation exchange resin and after removing it by filtration. Sodium content was measured by atomic absorption spectroscopy in a graphite furnace. The results of these measurements are shown in Table 1 below.

Note (1) Dyanion CR manufactured by Mitsubishi Kasei
-10. The chelating resin is a cross-linked styrene-divinylbenzene copolymer having a side chain group of iminodiacetic acid and has an average particle diameter of 1.2 μm.

Note (2) Amberlist 15 manufactured by Rohm and Haas. This cation exchange resin is styrene-
It is a divinylbenzene sulfonate copolymer.

Example 2 The same novolaks, EL and E as prepared in Example 1
The EP solution (173.4 g) was placed in a plastic bottle. The same chelating resin as used in Example 1 (3.5
g) was added to this novolak solution.

The resulting suspension was rotated on a bottle rotator for 24 hours at ambient temperature. The chelate resin particles were removed from the suspension by filtering the suspension through a membrane filter having a pore size of 0.2 μm.

After this treatment, the same cation exchange resin used in Example 1 (3.5 g) was added to the novolak solution filtrate.

The resulting suspension was rolled in a bottle rotator for another 24 hours at ambient temperature. The cation exchange resin was removed from the suspension through a membrane filter with a pore size of 0.2 μm.

Both the chelate resin particles and the cation exchange resin particles were prewashed with ethyl lactate in the same manner as described in Example 1.

The sodium and iron impurity contents of the novolac solution were measured by the same analytical method as described in Example 1 before the chelate resin treatment and after the cation exchange resin treatment. The results of these measurements are shown in Table 1 below.

Example 3 The same novolak, EL, and EEP solution (173.4 g) as prepared in Example 1 was placed in a plastic bottle. Another type of chelating resin ⁽³⁾ (3.5 g),
The same type of cation exchange resin used in Example 1 (3.5 g) was then added to the bottle. Both the chelate resin and the cation exchange resin were prewashed with ethyl lactate in the same manner as described in Example 1.

The resulting suspension was rolled in a bottle rotator for 24 hours. The chelates and cation exchange resin particles are then filtered through the suspension through a membrane filter having a pore size of 0.2 μm,
Removed from suspension.

The sodium and iron impurity contents in the novolak solution were measured by the same analytical method as described in Example 1 before the addition of the chelate and the cation exchange resin particles and after removing them by filtration. .. The results of these measurements are shown in Table 1 below.

Note (3) Dyanion CR manufactured by Mitsubishi Kasei
-20. The chelate resin is a cross-linked styrene-divinylbenzene copolymer resin having polyamine functional chelate groups in the copolymer and has an average particle size of 1.2 μm.

Example 4 The same novolaks, EL and E as prepared in Example 1
The EP solution (173.4 g) was placed in a plastic bottle. The Dianion CR-20 chelating resin used in Example 3 was added to this bottle.

The resulting suspension was rolled in a bottle rotator for 24 hours. This chelate resin particle is 0.2 μm
The suspension was removed from the suspension by filtering the suspension through a membrane filter having a pore size of.

After this treatment, the same cation exchange resin used in Example 1 (3.5 g) was added to the filtrate of the novolac solution.

The resulting suspension is 24 at ambient temperature.
Rotate in a bottle rotator for hours. Cation exchange resin particles were removed from the suspension through a membrane filter with a pore size of 0.2 μm.

Both the chelate resin particles and the cation exchange resin particles were prewashed with ethyl lactate in the same manner as described in Example 1.

The sodium and iron impurity contents of the novolak solution were measured by the same analytical method as described in Example 1 before the chelate resin treatment and after the cation exchange resin treatment. The results of these measurements are shown in Table 1 below.

Comparative Example 1 The same novolaks, EL and E as prepared in Example 1
The EP solution (173.4 g) was placed in a plastic bottle. The cation exchange resin used in Examples 1-4, Amberlyst 15 (3.5 g) was added to this bottle.

The resulting suspension was rolled in a bottle rotator for 24 hours. Cation exchange resin particles were then removed from the suspension by filtering the suspension through a membrane filter having a pore size of 0.2 μm.

The sodium and iron impurity contents in the novolac solution were measured by the same analytical method as described in Example 1 before the addition of the cation exchange resin and after removing it by filtration. The results of these measurements are shown in Table 1 below.

Comparative Example 2 The same novolaks, EL and E as prepared in Example 1
The EP solution (173.4 g) was placed in plastic.
The chelating resin used in Examples 1 and 2, Dyanion CR-10 (3.5 g) was added to the bottle.

The suspension obtained was rolled in a bottle rotator for 24 hours. Chelate resin particles were removed from the suspension by filtering the suspension through a membrane filter having a pore size of 0.2 μm.

The sodium and iron impurity contents in the novolac solution were measured by the same analytical method as described in Example 1, before the addition of the chelate resin particles and after their removal by filtration. The results of these measurements are shown in Table 1 below.

Comparative Example 3 The same novolaks, EL and E as prepared in Example 1
The EP solution (173.4 g) was placed in a plastic bottle. The chelating resin dianion CR-20 (3.5 g) used in Examples 3 and 4 was added to this bottle.

The resulting suspension was rolled in a bottle rotator for 24 hours. Chelate resin particles were removed from the suspension by filtering the suspension through a membrane filter having a pore size of 0.2 μm.

The sodium and iron impurity contents in the novolak solution were measured by the same analytical method as described in Example 1, before the addition of the chelate resin particles and after their removal by filtration. The results of these measurements are shown in Table 1 below.

[0092]

[Table 1]

The following Examples and Comparative Examples show the effects when the method of the present invention is applied to the sensitivity enhancer (that is, TRISP-PA) or the bone nucleus (7-PyOL) of the photoactive compound. ..

Comparative Example 4 TRISP-PA / acetone solution contacted only with Dyanion CR-10 chelating resin TRISP- in microelectronic grade acetone.
A 10% (w / w) solution of PA was microfiltered into a plastic bottle through a 0.2 μm membrane filter. Dianion CR- for this filtered solution
10% chelating resin was added in a 2% amount (w / w). The chelating resin was washed with acetone before use.

The obtained suspension was rotated on a bottle rotator for 24 hours. The chelate resin particles were removed from the suspension by decantation.

The sodium and iron impurity contents in the TRISP-PA solution were measured before microfiltration, after microfiltration and after decanting from the chelate resin, respectively. Sodium content was measured by flame or graphite furnace atomic absorption spectroscopy. Iron content was measured by inductively coupled plasma atomic absorption spectroscopy. The results of these measurements are shown in Table 2 below.

Comparative Example 5 TRISP-PA / Acetone Solution Contacted Only with Dyanion CR-20 Chelating Resin Microfiltered T as prepared for Comparative Example 4
A 10% (w / w) solution of RISP-PA was placed in a plastic bottle. 2% (w / w) in this filtered solution
Dianion CR-20 chelate resin was added. The chelating resin was washed with acetone before use.

The resulting suspension was rotated on a bottle rotator for 24 hours. The chelate resin particles were removed from the suspension by decantation.

The sodium and iron impurity contents in the TRISP-PA solution were measured before microfiltration, after microfiltration and after decanting from the chelate resin, respectively.
Sodium content was measured by flame or graphite furnace atomic absorption spectroscopy. Iron content was measured by inductively coupled plasma atomic absorption spectroscopy. The results of these measurements are shown in Table 2 below.

Example 5 Dyanion CR-10 chelate resin and RCP-22H
TRISP-PA / acetone solution contacted with cation exchange resin The same microfiltered TR prepared for Comparative Example 4.
A 10% (w / w) solution of ISP-PA was placed in a plastic bottle. Add 2% (w / w) Dyanion CR-10 chelate resin and 2% (w / w) RCP to the filtered solution.
-22H ⁽⁴⁾ cation exchange resin was added. The chelate resin and the cation exchange resin were washed with acetone before use.

The resulting suspension was rolled on a bottle rotator for 24 hours. The particles of chelate resin and cation exchange resin were removed from the suspension by decantation.

The sodium and iron impurity contents in the TRISP-PA solution were measured before microfiltration, after microfiltration and after decanting from the chelate resin, respectively.
Sodium content was measured by flame or graphite furnace atomic absorption spectroscopy. Iron content was measured by inductively coupled plasma atomic absorption spectroscopy. The results of these measurements are shown in Table 2 below.

Note (4) RCP-22H is manufactured by Mitsubishi Kasei. The cation exchange resin is a styrene sulfonic acid-divinylbenzene copolymer, a highly porous crosslinked particulate resin.

Example 6 Dyanion CR-20 chelate resin and RCP-22H
TRISP-PA / Acetone Solution Contacted with Cation Exchange Resin A 10% (w / w) solution of TRISP-PA microfiltered as prepared for Comparative Example 4 was placed in a plastic bottle. .. Add 2% (w /
w) Dyanion CR-20 chelate resin and 2% (w /
w) RCP-22H ⁽⁴⁾ cation exchange resin was added. The chelate resin and the cation exchange resin were washed with acetone before use.

The resulting suspension was rotated on a bottle rotator for 24 hours. The particles of chelate resin and cation exchange resin were removed from the suspension by decantation.

The sodium and iron impurity contents in the TRISP-PA solution were measured before microfiltration, after microfiltration and after decanting from the chelate resin, respectively. Sodium content was measured by flame or graphite furnace atomic absorption spectroscopy. Iron content was measured by inductively coupled plasma atomic absorption spectroscopy. The results of these measurements are shown in Table 2 below.

Comparative Example 6 7-PyOL / Acetone Solution in Contact with Dyanion CR-10 Chelate Resin Only 7-PyOL in Microelectronic Grade Acetone
Of 10% (w / w) solution was microfiltered through a 0.2 μm membrane filter into a plastic bottle. Dianion CR-1 is added to the filtered solution.
0% chelating resin was added in a 2% amount (w / w). The chelating resin was washed with acetone before use.

The resulting suspension was rotated on a bottle rotator for 24 hours. The chelate resin particles were removed from the suspension by decantation.

The sodium and iron impurity contents in the 7-PyOL solution were measured before microfiltration, after microfiltration and after decantation from the chelate resin, respectively. Sodium content was measured by flame or graphite furnace atomic absorption spectroscopy. Iron content was measured by inductively coupled plasma atomic absorption spectroscopy. These measurement results are shown in Table 2 below.
Shown inside.

Comparative Example 7 7-PyOL / Acetone Solution Contacted Only with Dianion CR-20 Chelate Resin A 10% (w / w) solution of 7-PyOL microfiltered in the same manner as prepared for Comparative Example 6. Was placed in a plastic bottle. To this filtered solution was added 2% (w / w) dianion chelate resin. The chelating resin was washed with acetone before use.

The resulting suspension was rotated on a bottle rotator for 24 hours. The chelate resin particles were removed from the suspension by decantation.

The contents of sodium and iron impurities in the 7-PyOL solution were measured before microfiltration, after microfiltration and after decantation from the chelate resin. Sodium content was measured by flame or graphite furnace atomic absorption spectroscopy. Iron content was measured by inductively coupled plasma atomic absorption spectroscopy. These measurement results are shown in Table 2 below.
Shown inside.

Example 7 Dyanion CR-10 chelate resin and RCP-22H
7-PyOL / Acetone Solution Contacted with Cation Exchange Resin A 10% (w / w) solution of 7-PyOL microfiltered as prepared for Comparative Example 6 was placed in a plastic bottle. .. To this filtered solution was added 2% (w / w) Dyanion CR-10 chelate resin and 2% (w / w) RCP-22H ⁽⁴⁾ cation exchange resin. The chelate resin and the cation exchange resin were washed with acetone before use.

The resulting suspension was rotated on a bottle rotator for 24 hours. The particles of chelate resin and cation exchange resin were removed from the suspension by decantation.

The contents of sodium and iron impurities in the 7-PyOL solution were measured before microfiltration, after microfiltration, and after decantation from the chelate resin. Sodium content was measured by flame atomic absorption spectroscopy. Iron content was measured by inductively coupled plasma atomic absorption spectroscopy. The results of these measurements are shown in Table 2 below.

Example 8 Dyanion CR-20 chelate resin and RCP-22H
7-PyOL / acetone solution contacted with cation exchange resin The same microfiltered 7 prepared for Comparative Example 6
A 10% (w / w) solution of PyOL was placed in a plastic bottle. 2% (w / w) Dyanion CR-20 resin and 2% (w / w) RCP-2 were added to the filtered solution.
2H ⁽⁴⁾ cation exchange resin was added. The chelate resin and the cation exchange resin were washed with acetone before use.

The resulting suspension was rotated on a bottle rotator for 24 hours. The particles of chelate resin and cation exchange resin were removed from the suspension by decantation.

The contents of sodium and iron impurities in the 7-PyOL solution were measured before microfiltration, after microfiltration, and after decantation from the chelate resin. Sodium content was measured by flame or graphite furnace atomic absorption spectroscopy. Iron content was measured by inductively coupled plasma atomic absorption spectroscopy. The results of these measurements are shown in Table 2 below.

[0119]

[Table 2]

Example 9 Cation exchange resin ⁽²⁾ (10 g) was washed with an aqueous solution (100 g) containing 25% by weight of tetramethylammonium hydroxide (TMAH). This washing was done by suspending the cation exchange resin in the TMAH solution in a plastic bottle. The bottle was rolled in a bottle rotator for 30-40 minutes at ambient temperature. Then, the resin particles were separated by decanting the TMAH solution. The resin particles were resuspended in the same TMAH solution. The gradient and resuspension are repeated twice more to thoroughly wash the particles.
The particles are collected by the final decantation of TMAH.

A meta / para mixed cresol novolac resin similar to that used in Example 1 (60 mol% m-cresol / 40 mol% p-cresol) was dissolved in ethyl lactate. The solid content of the obtained product is 30% by weight.
Met.

To this novolak resin solution was added the prewashed cation exchange resin. The amount of cation exchange resin added is 2% by weight of the solution. The resulting suspension was rotated on a bottle rotator for 24 hours at ambient temperature. The cation exchange resin was removed by filtration through a membrane filter with a pore size of 0.2 μm.

The sodium content in novolac was measured by graphite furnace atomic absorption spectroscopy. For the pH measurement, the novolac / ethyl lactate solution treated as described above is used.
60/40 ethyl lactate to water with deionized water
It was performed after diluting so that the volume ratio was set to. This dilution is necessary to obtain a stable pH value. The results of these analyzes are shown in Table 3 below.

Comparative Example 8 The method of Example 9 was repeated except that the cation exchange resin was washed with ethyl lactate (100 g) instead of the aqueous solution of TMAH. Sodium and pH
Level was measured according to the same method as described in Example 9. The results are shown in Table 3.

[0125]

[Table 3]

The data in this table show that prewashing the cation exchange resin with the TMAH solution still removes substantially the same amount of sodium impurities without an undesired reduction in the pH of the resin solution.

Although the present invention has been described above with reference to specific embodiments thereof, it will be apparent that many changes, modifications and variations can be made without departing from the inventive concept disclosed herein. It is therefore intended to cover all such changes, modifications and variations that fall within the spirit and broader scope of the appended claims.

 ─────────────────────────────────────────────────── ───Continued from the front page (72) Inventor Edward A. Fittsu The Herald, Rhode Island, USA 02806. Burlington. Fairview Circle 1 (72) Inventor Lawrence Huereira, Massachusetts, USA 02720. Forever River. Wallnut Street 598

Claims (7)

[Claims] 1. (a) Dissolving a resist component in a solvent; (b) Contacting the resist component solution with a cation exchange resin and a chelate resin for a sufficient period of time so that metal impurities on the cation exchange and chelate resin A method for removing metal impurities from a resist component, which comprises the steps of adsorbing at least a part thereof; and (c) separating the cation exchange and the chelate resin carrying the metal impurities from the resist component solution. 2. The method according to claim 1, wherein the resist component solution is contacted with the cation exchange removal and chelating resin at the same time. 3. The method according to claim 1, wherein the resist component solution is sequentially contacted with the cation exchange resin and the chelate resin. 4. The method according to claim 1, wherein the method of contacting comprises adding the cation exchange resin and the chelate resin to the resist component solution. 5. The method according to claim 1, wherein the chelating resin has polyamine chelating groups. 6. The contacting step (b) is sufficient to allow the resist component solution to contain sodium and iron at 100 ppb or less after the separating step (c), respectively. The method of claim 1, wherein 7. (a) Dissolving a resist component in a solvent; (b) Contacting the resist component solution with a cation exchange resin and a chelate resin for a sufficient period of time to allow metal impurities on the cation exchange and chelate resin. At least partly adsorbed, the cation exchange resin and optionally the chelating resin having been pre-washed with a solution of a quaternary ammonium salt compound; and (c) removing metal impurities from the resist component solution. A method for removing metal impurities from a resist component, characterized by the steps of separating the supported cation exchange and chelating resin.