JP5839226B2 - Resist residue removal composition - Google Patents

Description

  The present invention relates to a resist residue removing composition used for the production of an electronic circuit on a semiconductor substrate such as a semiconductor integrated circuit and a semiconductor element circuit of a liquid crystal panel. Specifically, the present invention relates to a resist residue removing composition used for removing a resist residue generated when a copper wiring is formed on a semiconductor substrate using a resist.

  Conventionally, aluminum has been mainly used as a wiring material in electronic circuits such as semiconductor integrated circuits and semiconductor element circuits of liquid crystal panels. However, with the narrowing of the wiring width or the enlargement of liquid crystal display devices such as liquid crystal televisions, copper, which is a metal with lower resistance and lower cost, has been proposed as a new wiring material.

  A multilayer wiring is formed in a semiconductor integrated circuit, a semiconductor element circuit, or the like. In general, in the step of forming wiring, a radiation sensitive resist (also simply referred to as a resist) is formed on an interlayer insulating film, and is patterned by a method such as exposure and development. Next, the interlayer insulating film is dry-etched using the patterned resist as a mask to form a trench or hole for embedding the copper wiring. At this time, the resist is usually ashed (ashed) and deposited as residues in trenches and holes as oxides of various materials. The resist residue removing composition is mainly used in a step after forming trenches and holes, and is used for stripping and removing unnecessary resist or resist residues.

  As a stripping remover for resists or resist residues, organic alkalis, inorganic alkalis, organic acids, inorganic acids, polar solvents, mixed compositions thereof or aqueous solutions thereof are often used. Among these, it is known that a mixture using hydrofluoric acid or a mixture using various amines is effective for removing a resist residue generated during wiring formation in a semiconductor substrate manufacturing process. Compositions containing fluoride ions are widely used because of their high detergency and treatment at room temperature.

  For example, Patent Document 1 describes that a resist residue is stripped and removed using a resist removing cleaning solution containing ammonium fluoride and a water-soluble solvent and having a pH of 4 to 8. Patent Document 2 describes that a resist residue is stripped and removed using a resist residue removing liquid composition comprising an aqueous solution containing sulfuric acid and a trace amount of hydrofluoric acid. Further, Patent Document 3 describes that a resist residue is peeled and removed by using a cleaning solution containing nitric acid, sulfuric acid, a fluorine compound, and a corrosion inhibitor and having a pH of 3-7.

  By the way, the resist or resist residue stripping composition used in the copper wiring process in semiconductor integrated circuits, semiconductor element circuits, etc. has (1) low corrosiveness to the lower layer copper wiring exposed at the hole bottom. (2) Ability to remove copper oxide-based compounds formed on the copper surface at the bottom of the holes generated in the wiring process, and (3) Silicon oxidation formed on the walls of the holes and trenches generated in the same wiring process The ability to remove physical compounds is required. However, since the conventional amine-based residue stripping removal composition has high copper corrosiveness and low cleaning ability, these three required performances cannot be satisfied. Moreover, none of the fluorine-based resist residue stripping / removing agents in Patent Documents 1 to 3 satisfy these three required performances.

  On the other hand, Patent Document 4 discloses a composition containing about 5% by mass of an oxidizing agent, about 10% by mass of a fluoride reducing agent, and about 0.01% by mass of an organic acid. Phosphoric acid is used as an oxidizing agent. It is disclosed that hydrofluoric acid can be used as the fluoride reducing agent and citric acid can be used as the organic acid. However, this composition is intended to form a metal oxide film with an oxidizing agent and remove the metal oxide film with a fluoride such as hydrogen fluoride, and contains about 10% by mass of fluoride. Therefore, there is a problem that the interlayer insulating film is corroded. Patent Document 5 discloses a wide range of compositions containing at least one acid selected from a number of options including hydrofluoric acid, phosphoric acid, citric acid and the like and at least one of hydrogen peroxide. However, there is no description or exemplification of an aspect, a blending ratio, or the like that is specifically selected from these many options and blended, and no actual use example is described.

JP 2004-094203 A JP 2005-173046 A JP 2005-150236 A JP 2004-363611 A Special table 2007-505509 gazette

  Accordingly, the present invention provides a copper surface at the bottom of the hole that is generated in the wiring process and has low corrosiveness to the lower layer copper wiring exposed at the bottom of the hole in a multilayer copper wiring process in a semiconductor integrated circuit, a semiconductor element circuit, etc. The ability to remove copper oxide-based compounds formed above and the ability to remove silicon oxide-based compounds formed on the walls of holes and trenches generated in the same wiring process is excellent, and can corrode interlayer insulation films. It is an object to provide a resist residue removing composition.

The present invention comprises at least one selected from the group consisting of component (A): phosphoric acid, phosphate, sulfuric acid and sulfate,
Component (B): an organic acid,
Component (C): hydrofluoric acid and / or hydrofluoric acid salt,
Resist residue removal used in the step of forming a copper wiring using a resist, containing component (D): water, and containing component (C) in an amount of 0.01 to 2% by weight based on the total amount of the composition It is a composition.
In one aspect of the present invention, component (A) is at least one selected from the group consisting of phosphoric acid, phosphate and sulfate.
In another embodiment of the present invention, component (A) is a phosphate and / or sulfate.
In another aspect of the present invention, component (B) is at least one selected from the group consisting of citric acid, malic acid, lactic acid, succinic acid, malonic acid, and acetic acid.
In another aspect of the present invention, component (C) is ammonium fluoride.
In another one aspect | mode of this invention, a component (A) is contained 0.01 to 50weight% with respect to the composition whole quantity.
In another embodiment of the present invention, the pH is 3 or less.

  With the above-described configuration, the composition of the present invention has low corrosiveness to copper wiring, excellent removal ability for copper oxide compounds, and removal ability for silicon oxide compounds, and can corrode interlayer insulating films. Absent. Therefore, in the multilayer copper wiring process using a resist in a semiconductor integrated circuit, a semiconductor element circuit, or the like by the composition of the present invention, (1) without corroding the lower layer copper wiring exposed at the bottom of the hole, (2) Remove the copper oxide compound formed on the copper surface at the bottom of the hole generated in the wiring process and (3) the silicon oxide compound formed on the wall surface of the hole and trench generated in the same wiring process. And a highly reliable copper wiring can be formed.

  As said component (A), at least 1 sort (s) selected from the group which consists of phosphoric acid, a phosphate, a sulfuric acid, and a sulfate is used. Examples of the phosphate include, for example, ammonium dihydrogen phosphate, diammonium hydrogen phosphate, triammonium phosphate, sodium dihydrogen phosphate, disodium hydrogen phosphate, trisodium phosphate, potassium dihydrogen phosphate, phosphoric acid Dipotassium hydrogen, Tripotassium phosphate, Tetramethylammonium dihydrogen phosphate, Ditetramethylammonium hydrogen phosphate, Tritetramethylammonium phosphate, Ethanolamine phosphate, Diethanolamine phosphate, Triethanolamine phosphate Salt. Examples of the sulfate include ammonium sulfate, sodium sulfate, potassium sulfate, tetramethylammonium sulfate, and ethanolamine sulfate. Among these, a phosphate is preferable, and the phosphate is preferably ammonium dihydrogen phosphate, diammonium hydrogen phosphate, or triammonium phosphate.

  The concentration of the component (A) is preferably 0.01 to 50% by weight, more preferably 0.1 to 25% by weight, and further preferably 0.1 to 15% by weight in the composition. Component (A) has the ability to remove copper oxide compounds.

  As the component (B), an organic acid is used. The organic acid is not particularly limited, and examples thereof include citric acid, malic acid, lactic acid, succinic acid, malonic acid, acetic acid, glycine, and alanine. These may be used alone or in combination of two or more. Among these, preferably citric acid, malic acid, lactic acid, succinic acid, malonic acid and acetic acid are at least one selected from the group consisting of citric acid, malic acid and lactic acid, more preferably Citric acid and lactic acid.

  The concentration of the component (B) is preferably 0.01 to 20% by weight, more preferably 0.1 to 15% by weight, and further preferably 1.0 to 5.0% by weight in the composition. The component (B) has a copper anticorrosion performance and a copper oxide removal performance.

  Component (C) may be hydrofluoric acid, hydrofluoric acid salt, or a combination of both. Examples of the hydrofluoric acid salt include ammonium fluoride, tetramethylammonium fluoride, tetraethylammonium fluoride, and tetrabutylammonium fluoride, and one or more of these can be used. Of these, hydrofluoric acid salt is preferable, and ammonium fluoride is preferable as the hydrofluoric acid salt.

  The concentration of the component (C) is 0.01 to 2% by weight in the composition. If it exceeds 2% by weight, corrosion of the interlayer insulating film occurs, and if it is less than 0.01% by weight, the removal performance of the silicon-based residue is deteriorated. Preferably, it is 0.04-1.5 weight%, More preferably, it is 0.08-1.0 weight%, More preferably, it is 0.15-0.70 weight%.

  Generally, the blending amount of the components (A) to (C) is more preferably 1.0 to 15% by weight, and even more preferably 1.0 to 8.0% by weight.

  The pH of the composition is not particularly limited, but is preferably pH 1.0 to 8.0, more preferably pH 2.0 to 6.0, from the viewpoints of copper oxide removal ability and silicon residue removal ability. . Moreover, it is preferable that it is pH 3.0 or less from a viewpoint of improving a copper oxide residue removal capability.

  Water is used as the component (D). The water is preferably water from which impurities have been removed by physical or chemical treatment.

  The blending amount of component (D) may be the balance of the above components (A) to (C) in the composition, or when using any additional components described later, the blending amount is subtracted. The rest. However, the amount of water is generally preferably 50% by weight or more, and more preferably 75% by weight or more.

  The resist residue removing composition of the present invention can optionally use other additional components. As said additional component, an organic solvent can be included, for example in order to improve residue removability. Further, a surfactant may be included for improving wettability. Furthermore, the copper anticorrosive agent generally used can also be included. The organic solvent is not particularly limited, and examples thereof include N, N-dimethylacetamide, N, N-diethylacetamide, ethyl diethylene glycol, methyl diethylene glycol, dimethyl sulfoxide and the like. The surfactant is not particularly limited, and examples thereof include an anionic surfactant such as sodium dodecylbenzenesulfonate, and a nonionic surfactant containing an ethylene oxide or propylene oxide skeleton. The copper anticorrosive is not particularly limited, and examples thereof include nitrogen-containing cyclic compounds such as benzotriazole, triazole, histidine, and thiol compounds.

  As the compounding amount of the additional component, the compounding amount of the organic solvent is preferably 1.0 to 70% by weight, more preferably 5.0 to 50% by weight, and the compounding amount of the surfactant is 0.001 to 0.001. 5.0 wt% is preferable, 0.01 to 1.0 wt% is more preferable, and the compounding amount of the copper anticorrosive is preferably 0.01 to 5.0 wt%, 0.01 to 1.0 wt% Is more preferable.

  The resist residue removing composition of the present invention is suitably used for stripping and removing unnecessary resist or resist residues in a multilayer copper wiring process using a resist in a semiconductor integrated circuit, a semiconductor element circuit, or the like. Preferably, it is used in a step after the formation of the trench and the hole, and the residue generated in the trench and the hole after the dry etching and ashing can be removed while preventing the corrosion of the underlying copper wiring. Alternatively, the formed copper film can be used in a process of removing residues such as resist residues and reactants remaining on the wiring side wall and wiring while dry etching and ashing to prevent wiring thinning and voids. . The treatment using the resist residue removing composition of the present invention is applied to the substrate by a method such as coating, spraying or dipping, and the treatment temperature is preferably 10 to 50 ° C., more preferably 20 to 40 ° C., treatment time. As for this, Preferably it can carry out in 2 seconds-30 minutes, More preferably, it is 40 seconds-20 minutes, Then, running water rinse and drying can be performed as needed.

  EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples, but the present invention is not limited to these examples.

Examples 1 , 3 to 4, 8, 9, 12, 13, 17 Reference Example 2, 5 to 7, 10, 11, 14 to 16 , 18 to 24 , Comparative Examples 1 to 9
Each component of Examples, Reference Examples, and Comparative Examples was mixed with the formulations shown in Table 1-1, Table 2-1, and Table 3-1, and resist residue removal compositions were prepared. The pH of each composition was measured at 25 ° C., and the results were shown. The following evaluation was performed using each composition. The results are shown in Table 1-2, Table 2-2, and Table 3-2.

Evaluation 1. Copper low corrosivity It was evaluated by measuring the copper etch rate. First, copper was sputtered on a silicon substrate to prepare a substrate for measuring an etch rate. This copper substrate piece was immersed in the resist residue removing composition at 25 ° C., and the change in film thickness was measured to measure the copper etch rate. In Tables 1-2 to 3-2, the results with a copper etch rate of 0.4 nm / min or less are indicated as “good” because the copper corrosivity is satisfactory and the low corrosion resistance of copper is good. In the case of other results, “x” was displayed.

2. Copper oxide residue removal ability It evaluated by measuring the etching rate of copper oxide. First, copper oxide was sputtered onto a silicon substrate to prepare an etch rate measurement substrate. This copper oxide substrate piece was immersed in the resist residue removing composition at 25 ° C., and the change in film thickness was measured to measure the copper oxide etch rate. In Tables 1-2 to 3-2, the result that the copper oxide etch rate was 1.0 nm / min or more was indicated as “◯” because the copper oxide residue removal ability was good because the copper oxide dissolution ability was high. In other cases, x was displayed.

3. Silicon-based residue removal capability It was confirmed by observation with a scanning electron microscope (SEM) and evaluated that the residue in the hole was removed. The wiring material at the bottom of the hole was copper, and a substrate was used in which a hole was formed in the silicon-based interlayer insulating film by dry etching, and the resist was ashed. Silicon-based residues adhere to the hole sidewalls in the substrate after dry etching and ashing. When it was confirmed by SEM observation that the residue adhering to the hole side wall was removed, it was indicated as “◯” because the silicon-based residue removal ability was good. Moreover, when the residue was not removed, it displayed as x.

4). Hole Shape The degree of corrosion of the interlayer insulating film was evaluated for the hole pattern substrate used in the test for removing the silicon-based residue. If the hole shape does not change at all before and after processing due to corrosion of the interlayer insulation film, it is indicated as ◎, slight surface roughness etc. is seen, but if it is practical, it is indicated as ○, and what changes greatly is indicated as ×. displayed.

In Table 1-1, Table 1-2, Table 2-1, and Table 2-2, as shown in Comparative Examples 1 to 9, any one of Component (A), Component (B), and Component (C) is included. If there is no resist residue removal composition or a resist residue removal composition containing a large amount of hydrofluoric acid, all of the low corrosion resistance of copper, silicon residue removal ability, copper oxide residue removal ability, and hole shape are all good. No results were obtained. On the other hand, in the resist residue removal compositions shown in Examples 1 , 3 to 4 , 8 , 9 , 12 , and 13 , all of the low corrosion resistance, silicon residue removal ability, and copper oxide residue removal ability of copper are good. I was able to get a good result.

In addition to the component (A), the component (B), the component (C), and water, the resist residue removal composition of Example 17 shown in Tables 3-1 and 3-2 includes an organic solvent, A surfactant or a copper anticorrosive agent was contained, and good results were obtained with all of the low corrosion resistance of copper, silicon residue removal ability, and copper oxide residue removal ability.

  From the above results, it was shown that the resist residue removal composition of the present invention has higher residue removal performance and lower corrosion resistance of copper than conventional resist strippers.

Claims (4)

Component (A): at least one selected from the group consisting of phosphoric acid and phosphate,
Component (B): at least one organic acid selected from the group consisting of citric acid, malic acid, lactic acid, succinic acid, malonic acid, and acetic acid;
Component (C): hydrofluoric acid and / or hydrofluoric acid salt,
Component (D): containing water,
Using a resist containing 0.01 to 2% by weight of component (C) with respect to the total amount of the composition, containing 50% by weight or more of component (D) with respect to the total amount of the composition, and having a pH of 3 or less A resist residue removing composition used in a process of forming a copper wiring.   The resist residue removing composition according to claim 1, wherein component (A) is phosphoric acid. Component (C), the resist residue removal composition of claim 1 or 2 is ammonium fluoride. The resist residue removing composition according to any one of claims 1 to 3 , wherein the component (A) is contained in an amount of 0.1 to 25 wt% based on the total amount of the composition.