JP2007034067A - Cleaning liquid for lithography - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a cleaning liquid that shows uniformly favorable cleaning property on a resist of ArF specification which is not sufficiently cleaned with a conventional cleaning liquid, and that shows high drying property after processing without deteriorating characteristics of a resist by cleaning. <P>SOLUTION: The cleaning liquid for lithography comprises a single alkoxycarboxylic acid alkylester or a mixture solvent of the ester with alkoxybenzene. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention is a cleaning liquid used when producing a resist pattern by lithography, and is particularly suitable for dissolving and removing an unnecessary portion of a resist film provided on a substrate and a photoresist composition remaining in a photoresist supply apparatus. The present invention relates to a cleaning liquid for lithography.

Conductive substrates used in the manufacture of semiconductor elements and liquid crystal display elements generally undergo a process of applying a photoresist on a silicon wafer or glass substrate to form a photoresist pattern. When applying this resist, the edge portion of the substrate Since the resist adheres to the back surface portion and becomes a hindrance during the subsequent resist pattern formation, this unnecessary resist needs to be washed and removed in advance.
As the cleaning liquid used for these purposes, a solvent that can efficiently dissolve and remove unnecessary resists, is quickly dried, and does not impair the characteristics of the resist film after cleaning is used.

  In addition, when a resist pattern is manufactured using a substrate having a photoresist film on the surface, photoresist residues deposit on the equipment, piping, and equipment used, and adhere and dry, thereby hindering subsequent operations. Various solvents are used as cleaning agents for dissolving and removing the resist deposits. These cleaning agents are desired to be able to completely dissolve and remove the resist adhering dry matter in as short a time as possible while not adversely affecting the subsequent processing steps.

  By the way, many of these cleaning agents are mainly composed of a specific ether solvent, ester solvent or a mixture thereof, or a mixture of these with a specific ketone solvent, lactone solvent or alcohol solvent.

  So far, for example, a resist removing cleaning solution in which a basic substance is dissolved in a glycol ether such as ethylene glycol, propylene glycol or a lower alkyl ether of dipropylene glycol as a main component of a specific ether solvent. (See Patent Document 1), resist remover comprising dipropylene glycol mono-lower alkyl ether (see Patent Document 2), resist cleaning removal solvent comprising propylene glycol alkyl ether, ketone and lactam or lactone (Patent Document 3) Reference), propylene glycol alkyl ether, ethylene glycol alkyl ether, or a cleaning agent for lithography composed of alkoxybutanol and a lower alcohol (see Patent Document 4), and a specific ester solvent is known. As a component, a resist cleaning solvent composed of a monooxocarboxylic acid ester and a ketone (see Patent Document 5), a resist cleaning solvent composed of butyl acetate or ethyl lactate and propylene glycol monoalkyl ether (see Patent Document 6) ), A photoresist cleaning thinner composition comprising ethyl lactate and ethyl-3-ethoxypropionate (see Patent Document 7), a lithography detergent comprising alkyl acetate or alkyl lactate and alcohol (see Patent Document 4), A thinner composition for removing a photoresist comprising alkyl lactate, propylene glycol monoalkyl ether acetate and a ketone (see Patent Document 8) is known.

  Moreover, the lithography cleaning liquid supply pipe installed in the semiconductor production line has a limited number of pipes, so all uses, specifically, cleaning in the cup, substrate edge cleaning, substrate back surface cleaning, There is a demand for a cleaning solution that can comprehensively cover pipe cleaning, rework cleaning, prewetting, and the like.

  In addition, it is difficult to dissolve the ArF excimer laser resist, which is a resist composed of an acrylic polymer, in the lithography cleaning liquid known so far, and the edge portion and the back surface portion of the substrate are cleaned well. The resist solution for ArF excimer laser can be removed from the resist supply apparatus (coater cup and pipe) to which ArF excimer laser resist residue has adhered, and the cleaning liquid for cleaning and removing these resists has a sufficient effect. I could not.

JP-A-9-269601 (Claims and others) JP-A-9-31147 (Claims and others) JP-A-11-218933 (Claims and others) JP 11-44960 A (Claims and others) JP-A-4-130715 (Claims and others) Japanese Patent Laid-Open No. 7-128867 (Claims and others) JP-A-10-104847 (Claims and others) JP 2005-128529 A (Claims and others)

  The present invention shows uniformly good cleaning properties with respect to ArF-specific resists that could not be sufficiently cleaned with conventional cleaning liquids, has good drying properties after processing, and resists by cleaning. The purpose of this invention is to provide a cleaning solution that does not impair the characteristics of the above.

  The present inventors can use a cleaning agent that can be used in the production of a resist pattern using a lithography technique, and that also exhibits excellent solubility in ArF resist residues that could not be removed by conventional cleaning solutions. As a result of earnest research to develop, as a result of alkoxycarboxylic acid alkyl ester alone or a mixture of this and alkoxybenzene, about 3 to 10 times the dissolving power of ArF resist residue compared to conventional cleaning agents. Based on this finding, the present inventors have made the present invention.

  That is, the present invention provides a cleaning liquid for lithography comprising an alkoxycarboxylic acid alkyl ester alone or a mixed solvent thereof with alkoxybenzene.

The cleaning agent of the present invention may be an alkoxycarboxylic acid alkyl ester alone or a mixture of an alkoxycarboxylic acid alkyl ester and an alkoxybenzene.
This alkoxycarboxylic acid alkyl ester is an alkyl ester of a carboxylic acid in which one hydrogen atom of the hydrocarbon group forming the carboxylic acid is substituted with an alkoxy group, and examples thereof include methoxyacetic acid and ethoxyacetic acid. And methyl, ethyl, and propyl esters of lower alkoxy fatty acids such as methoxypropionic acid, ethoxypyropionic acid, propoxypropionic acid, methoxybutyric acid, ethoxybutyric acid, and propoxybutyric acid. Particularly preferred among these are methyl 3-methoxypropionate, methyl 4-methoxybutyrate, ethyl 3-ethoxypropionate, and ethyl 4-ethoxybutyrate.

  In addition, from the viewpoint of solubility, the cleaning liquid of the present invention preferably uses an alkoxycarboxylic acid alkyl ester and an alkoxybenzene as a mixed solvent. Examples of such alkoxybenzene include a methoxy group, an ethoxy group, a propoxy group, and a pentoxy group. And alkoxybenzene substituted with an alkoxy group such as These benzenes may be further substituted with a lower alkyl group as desired. Examples of such a compound include anisole, phenetole, butylphenyl ether, pentylphenyl ether, methoxytoluene and the like. Of these, anisole is most preferable.

  In the cleaning agent of the present invention, this alkoxybenzene is preferably contained in a proportion of 50% by mass or less, particularly preferably 30% by mass or less, based on the total mass. In general, as a cleaning agent for use in lithography technology, it is required to completely dissolve a residue of a photoresist adhering to a substrate or a photoresist supply apparatus within 10 minutes.

  In order to remove the photoresist unnecessary portion on the substrate using the cleaning liquid of the present invention, after applying a necessary resist on the substrate by, for example, spin coating, the cleaning liquid is applied to the edge of the substrate or the back surface of the substrate or both. Contact is performed, and unnecessary portions of the resist film are washed away, and then dried.

  Whether or not the unnecessary resist on the substrate edge portion and the back surface portion has been removed can be confirmed by observation with a step measuring device or a scanning electron microscope, and whether or not the resist residue of the resist supply device has been removed, It can be confirmed visually.

  According to the present invention, the resist remaining on the resist unnecessary portion on the substrate, the coater cup, the piping, the connection point, etc. of the photoresist supply apparatus with a dissolving power about 3 to 10 times that of conventionally known solvents, particularly acrylic The residue of the system polymer can be efficiently dissolved and removed.

  Next, the best mode for carrying out the present invention will be described by way of examples. However, the present invention is not limited to these examples.

Example 1 and Comparative Examples 1-7
A photoresist for ArF (product name “TArF-P6111”, manufactured by Tokyo Ohka Kogyo Co., Ltd.) containing an acrylic polymer was dried under reduced pressure on a 90 ° C. water bath for 60 minutes to form a dried resist.
Next, this dried product was immersed in a cleaning solution shown in Table 1 (25 ° C.), and the time required until the dried product was completely dissolved was measured. The results are shown in Table 1.

GBL: γ-butyrolactone PM: propylene glycol monomethyl ether acetate PE: propylene glycol monomethyl ether EL: ethyl lactate MIBK: methyl isobutyl ketone CH: cyclohexanone MAK: methyl amyl ketone

  From this result, it can be seen that the methyl methoxypropionate alone has a remarkably high solubility in ArF resist as compared with other solvents alone.

Example 2
Using a mixed solvent in which anisole and methyl methoxypropionate were mixed at a ratio (mass ratio) shown in Table 2, the time required until the dried solid was completely dissolved was measured in the same manner as in Example 1. The results are shown in Table 2.

  From this result, it can be seen that when the methyl methoxypropionate is 70% by mass or more, particularly high dissolving power can be obtained.

Example 3
ArF photoresist (product name “TArF-P6111” manufactured by Tokyo Ohka Kogyo Co., Ltd.) and spinner (product name “DNS D-SPIN” manufactured by Dainippon Screen Mfg. Co., Ltd.) are used at 2500 rpm on a silicon wafer having a diameter of 200 mm. A resist film having a film thickness of 1.35 μm was formed by spin coating at a rotational speed of 10 seconds, and then heated and dried at 60 ° C. for 80 seconds.
Next, the cleaning liquid consisting of the cleaning agent of Example 1, that is, methyl methoxypropionate, was sprayed at a rate of 10 ml / min from a nozzle placed at a position 5 mm from the wafer edge at 25 ° C. to clean the resist film edge. And air dried for 30 seconds.
The edge part of the resist film thus treated was scanned using a stylus type surface shape measuring instrument (product name “DEKTAK8” manufactured by ULVAC, Inc.), and the enlarged pattern shape in the cross-sectional direction was measured. As a result, it was found that the resist film surface other than the edge portion was hardly affected, and unnecessary portions of the edge portion were almost removed.

Example 4
In place of the cleaning agent of Example 1, a cleaning agent comprising a mixture of anisole and methyl methoxypropionate in a mixing ratio of 30:70 was subjected to the same treatment on the same sample as in Example 3. Next, when the shape of the edge portion of the resist film was measured in the same manner as in Example 3, the resist film surface other than the edge portion was hardly affected, and unnecessary portions of the edge portion were almost removed. I found out.

Comparative Example 8
In place of the cleaning agent of Example 1, the same treatment as in Example 3 was performed using a cleaning liquid composed of a mixed solvent of methyl methoxypropionate and propylene glycol monomethyl ether in a mixing ratio of 50:50. Next, when the shape of the edge portion of the resist film was measured in the same manner as in Example 3, the unnecessary portion at the edge portion was hardly removed.

  The present invention removes the resist in the unnecessary portions of the end surface portion and the back surface portion that are generated when applying the resist on the substrate, and prevents the occurrence of product defects due to the presence of the unnecessary portions, as well as pipe cleaning and rework. It can be used for various purposes such as cleaning and pre-wetting.

Claims (7)

  A cleaning solution for lithography comprising an alkoxycarboxylic acid alkyl ester alone or a mixed solvent thereof with alkoxybenzene.   The lithography cleaning liquid according to claim 1, wherein the alkoxycarboxylic acid alkyl ester is a methoxypropionic acid alkyl ester.   The lithography cleaning liquid according to claim 1, wherein the alkoxybenzene is anisole.   The lithography cleaning liquid according to claim 1, comprising a mixed solvent of an alkoxycarboxylic acid alkyl ester and an alkoxybenzene.   The lithography cleaning liquid according to claim 4, wherein the compounding amount of alkoxybenzene is 50% by mass or less based on the total mass of the mixed solvent.   The lithography cleaning liquid according to any one of claims 1 to 5, for removing the acrylic polymer-containing photoresist composition. The lithography cleaning liquid according to any one of claims 1 to 6, for removing a residue of the acrylic polymer-containing photoresist composition attached to the photoresist supply apparatus.