JP2006258890A - Resist stripper for substrate process - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a resist stripper that can strip an ion-implanted resist having inferior stripping property at a relatively low temperature in a short time, considering problems that conventionally stripping a resist or an antireflection film in a substrate process (front end of line) in the manufacture of semiconductors is carried out by use of a mixture solution comprising sulfuric acid and hydrogen peroxide water (SPM cleaning liquid), however, the process shows low productivity and disadvantage from a viewpoint of cost and requires high concentration and a high temperature process, and in particular, an ion-implanted resist is further difficult to be stripped than a resist with no ion implanted and shows insufficient stripping property even with a SPM cleaning liquid. <P>SOLUTION: The resist stripper comprises ammonia and acetonitrile. The stripping liquid is excellent in resist stripping property, and particularly excellent in stripping the ion-implanted resist. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a resist stripping solution for a substrate process, and particularly to a resist stripping solution suitable for stripping an ion-implanted resist that is difficult to strip.

  Conventionally, resist removal in a substrate process (Front End of Line) has been conventionally performed by a mixed solution (SPM cleaning solution) composed of sulfuric acid and hydrogen peroxide in a batch type cleaning apparatus. As typical use conditions, it is carried out by treating with an SPM cleaning solution (sulfuric acid: hydrogen peroxide = 4: 1) at 100 to 120 ° C. for 10 minutes.

  However, under such conditions, the productivity is low and the cost is disadvantageous, so that replacement of a concentrated and high temperature solution such as an SPM cleaning solution has been desired.

  On the other hand, in the semiconductor manufacturing process, an ionized p-type or n-type impurity element is implanted into the Si substrate in order to form a p / n junction, but the ion-implanted resist is more than the resist that is not ion-implanted. It was much more difficult to remove the resist.

  In addition, a resist stripping solution containing hydrogen peroxide and a quaternary ammonium salt (for example, Patent Documents 1 and 2), a resist stripping solution containing an oxidizing agent, a chelating agent, a water-soluble fluorine compound, and an organic solvent (for example, Patent Documents) 3) A resist stripping solution containing hydrogen peroxide, ammonium ions, phosphoric acid and / or carbonate ions and having a pH of 5 or more (Patent Document 4) has been proposed. However, none of the resist stripping solutions are used in the substrate process, and it is not particularly related to ion-implanted resists that are difficult to strip, and there is no description about it.

  As described above, a resist stripping solution that can strip off a resist with poor stripping properties that has been ion-implanted in a substrate process at a low temperature in a short time has not been known.

JP 2002-202617 A JP 2003-5383 A JP 2000-258924 JP 2003-330205 A

An object of the present invention is to remove a resist having poor releasability implanted with ions at a relatively low temperature in a short time. That is, in particular, under the conditions of a temperature of 80 ° C. or less and a short time (˜1 minute) without damaging the exposed polycrystalline Si (poly-Si), Si oxide film (SiO ₂ ), etc. An object of the present invention is to provide a resist stripping solution capable of removing the injected resist having poor stripping property and antireflection film.

As a result of intensive studies on a resist stripping solution, particularly a resist stripping solution for a substrate process (hereinafter referred to as “resist stripping solution”), the present inventors have found that poly-Si in a mixed solution of ammonia, acetonitrile, and water at a specific concentration. Resist with poor peelability due to ion implantation of resist and / or antireflection film, especially arsenic or boron, at a temperature of 80 ° C. or less and for a short time (˜1 minute) without damaging SiO ₂ or the like The inventors have found that the antireflection film can be removed and have completed the present invention.

  That is, the present invention is a resist stripper containing ammonia and acetonitrile as essential components.

  The present invention is described in detail below.

  The resist stripping solution in the present invention is a resist and / or antireflection film applied on a substrate, then exposed to light, developed, processed by etching, ion implantation, etc. to form a circuit, and then the remaining resist and / or A solution used to remove the antireflection film.

  The resist and antireflection film used in the present invention are not particularly limited, and examples thereof include hydroxystyrene-based polymers and novolak-based polymers.

  In the present invention, after applying the resist and / or antireflection film on the substrate, exposure, development, etching, ion implantation and the like are performed to form a circuit, followed by peeling with the resist stripping solution of the present invention. .

  The resist stripping solution of the present invention comprises ammonia and acetonitrile as its components.

  Ammonia used in the resist stripping solution of the present invention has an action of stripping and removing the resist and / or the antireflection film. Ammonia is generally marketed as aqueous ammonia and can be used as aqueous ammonia. Although it can be easily obtained, it is preferable to use a high-purity product in order to maintain the cleanliness of the wafer.

  Acetonitrile used in the resist stripping solution of the present invention has an action of promoting dissolution and stripping of the resist and / or antireflection film. Acetonitrile is generally commercially available and can be easily obtained.

  An organic solvent can be added to the resist stripping solution of the present invention. There are no particular limitations on the organic solvent that can be used. For example, methanol, ethanol, propanol, butanol, ethylene glycol, diethylene glycol, alcohols such as propylene glycol, dipropylene glycol, glycerol, ethers such as dioxane and tetrahydrofuran, dimethylformamide, dimethylacetamide Amides such as methylpyrrolidone and dimethylimidazolidinone, esters such as dimethyl carbonate, ethylene carbonate and propylene carbonate, sulfoxides such as dimethyl sulfoxide, methoxyethanol, methoxypropanol, ethoxyethanol, ethoxypropanol, propoxyethanol, propoxypropanol, butoxyethanol , Butoxypropanol, diethylene glycol Ether alcohol such as nomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monopropyl ether, diethylene glycol monobutyl ether, dipropylene glycol monomethyl ether, dipropylene glycol monoethyl ether, dipropylene glycol monopropyl ether, dipropylene glycol monobutyl ether, propio Organic nitriles such as nitrile, butyronitrile, isobutyronitrile, succinonitrile, benzonitrile, adiponitrile and the like can be mentioned, and sulfoxide, ether alcohol and organic nitrile are particularly preferable because they promote the peeling of the resist. These may be used alone or in combination of two or more.

  The amount of the organic solvent used varies greatly depending on the use conditions, but the solvent content is preferably 99% by weight or less, more preferably 95% by weight or less, based on the total weight of the resist stripping solution. When the organic solvent exceeds 99% by weight, the peeling performance is lowered.

Water may be added to the resist stripping solution of the present invention. The water content is 50% by weight or less. If the amount is too large, other semiconductor materials such as SiO ₂ may be damaged.

  As a component amount of the resist stripping solution of the present invention, the ammonia content is 0.1 to 10% by weight, preferably 0.5 to 5% by weight. If the concentration of ammonia exceeds this range, the peeling effect is excellent, but a large amount of ammonia vapor is generated, making handling difficult. Conversely, if the amount is too small, the peeling effect becomes insufficient.

  The content of acetonitrile is 1 to 99% by weight, preferably 5 to 99% by weight. If it is too much or too little, the resist peeling effect is insufficient.

  The resist stripping solution of the present invention may be used by adding each component when stripping the resist, or may be used after mixing each component in advance.

  The resist stripping solution of the present invention is most preferably used when stripping a resist layer or an antireflective film that has deteriorated peelability due to treatment such as ion implantation among resist films coated on an inorganic substrate. .

  The resist stripping solution in the present invention can be used in a substrate process, for example. Here, the substrate process is a so-called FEOL (Front End of Line) process before the formation of the wiring structure in the semiconductor manufacturing process.

  The resist stripping solution of the present invention includes resists such as negative-type and positive-type resists that can be developed with an alkaline aqueous solution for i-line and KrF excimer lasers, and further ion-implanted with arsenic or boron. Exhibits particularly high releasability in peeling.

  The resist stripping solution of the present invention can strip the resist at a temperature of 20 ° C. to 80 ° C. for a cleaning time of 1 minute or less.

The resist stripping solution of the present invention is a resist, antireflection film at a temperature of 80 ° C. or less and for a short time (˜1 minute) without damaging polycrystalline Si (poly-Si), Si oxide film (SiO ₂ ), etc. Can be peeled off, and is particularly excellent as a resist stripping solution for a substrate process.

Hereinafter, the method of the present invention will be described with reference to examples, but the present invention is not limited thereto. In order to simplify the notation, the following abbreviations were used.
NH ₃ : ammonia MeCN: acetonitrile DMSO: dimethyl sulfoxide BP: butoxypropanol EG: ethylene glycol H ₂ O: water SA: sulfuric acid HPO: hydrogen peroxide Examples 1-7, Comparative Examples 1-4
A silicon wafer (post-baked at 120 ° C., manufactured by Advantech Co., Ltd.) coated with a positive resist in which 10 ¹⁴ ions / cm ² of arsenic were ion-implanted as ion species was applied to a stripping solution shown in Table 1 at 40 ° C. or 60 ° C., 1 It was immersed for a minute, then washed with water and dried.

The surface of the treated silicon wafer was observed with a scanning electron microscope and the resist peelability was examined. Also, the erosion of Si, poly-Si film, 60 ° C. The silicon wafer was formed a SiO ₂ film coating was immersed for 5 minutes, were evaluated by surface observation.

  Table 1 shows the stripping solution composition and stripping results.

The resist peelability and erosion were evaluated as follows.
<Resist peelability>
○: Completely peeled, Δ: Partially retained, ×: Residual on the entire surface <Si erosion>
○: No erosion, △: Partial erosion, ×: Heavy erosion

Claims (8)

A resist stripping solution comprising ammonia and acetonitrile. 2. The resist stripping solution according to claim 1, further comprising an organic solvent and / or water in addition to ammonia and acetonitrile. The resist stripping solution according to claim 1 or 2, wherein the organic solvent is at least one selected from the group consisting of alcohol, ether, amide, ester, sulfoxide, ether alcohol, and organic nitrile. Organic solvent alcohol, ether, amide, ester, sulfoxide ether alcohol, organic nitrile is methanol, ethanol, propanol, butanol, ethylene glycol, diethylene glycol, propylene glycol, dipropylene glycol, glycerol, dioxane, tetrahydrofuran, dimethylformamide, dimethylacetamide , Methylpyrrolidone, dimethylimidazolidinone, dimethyl carbonate, ethylene carbonate, propylene carbonate, dimethyl sulfoxide, methoxyethanol, methoxypropanol, ethoxyethanol, ethoxypropanol, butoxyethanol, butoxypropanol, propionitrile, butyronitrile, isobutyronitrile, Succinonitrile, benzonitrile, Resist stripping solution according to claim 1 及至 claim 3 is at least one selected from the group consisting of Jiponitoriru. The concentration of ammonia is 0.01 to 10% by weight, the concentration of acetonitrile is 1 to 99% by weight, the concentration of organic solvent is 99% or less, and the concentration of water is 50% by weight or less. Resist stripping solution. The resist stripping solution for a substrate process according to any one of claims 1 to 5, comprising ammonia and acetonitrile. The resist stripping solution according to any one of claims 1 to 6, which strips the resist and / or the antireflection film. The resist stripping solution according to any one of claims 1 to 6, wherein the resist and / or the antireflection film is an ion-implanted arsenic or boron.