JP2012252070A - Stripping agent composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a stripping agent composition that does not use urea as an anticorrosive but can reliably exhibit anticorrosion performance at normal temperature of about 20°C.SOLUTION: The stripping agent composition contains alkanol amine and an anticorrosive essentially comprising pyrogallol and is adjusted to a pH of 8 to 10. The alkanol amine exhibits a stripping function to remove a resist film and an etching residue; and the pyrogallol can strongly remove dissolved oxygen of a water content, provided that the pH is controlled to 8 to 10. Thus, the obtained stripping agent composition preliminarily prevents dissolved oxygen from reacting on a metal surface such as an exposed copper film, and exhibits an anticorrosion function.

Description

  The present invention relates to a release agent composition for treating a resist or impurities after dry etching, which is used in a manufacturing process of a semiconductor substrate or a liquid crystal panel.

  Conventionally, this type of release agent composition is known to contain not only a release agent but also an anticorrosive agent in order to suppress corrosion on a metal substrate containing aluminum or copper (for example, see Patent Document 1). ).

  Hereinafter, the release agent composition will be described with reference to FIGS.

  As shown in FIG. 3A, after a silicon oxide film 101, a silicon nitride film 102, and a silicon oxide film 103 are formed on a semiconductor substrate (not shown) on which elements such as transistors are formed, a chemical machine is formed. A copper wiring composed of the barrier metal film 104 and the copper film 105 is formed by using a damascene process utilizing mechanical polishing, and a silicon nitride film 106 and a silicon oxide film 107 are further formed thereon.

  Next, a resist film 108 patterned in a predetermined shape is provided on the silicon oxide film 107 (FIG. 3B).

  Next, using the resist film 108 as a mask, the silicon oxide film 107 is dry etched until the silicon nitride film 106 is exposed, thereby forming a through hole 110 (FIG. 3C). At this time, the etching residue 111 adheres to the inner wall of the through hole 110. Further, the silicon nitride film 106 may be etched in some through holes, and a part of the copper film 105 may be exposed.

  After the etching is completed, a part of the resist film 108 is removed by oxygen plasma ashing, and then a peeling process is performed using a release agent composition. By this peeling treatment, the resist film and the etching residue 111 are removed. At this time, although the copper film 105 is exposed in some through holes, the copper film 105 is damaged by using a release agent composition containing (a) urea or a urea derivative and (i) a hydroxy aromatic. The resist film and the etching residue 111 can be removed without giving (FIG. 4A).

  Thereafter, the silicon nitride film 106 is etched by changing the above etching and etching gas. At this time, although the etching residue 112 adheres to the inner wall of the through hole 110 (FIG. 4B), the copper film 105 is damaged by using the release agent composition containing the components (a) and (b). The etching residue 112 can be removed without giving (FIG. 4C).

  Thereafter, a barrier metal film 14 and a tungsten film 15 in which Ti and TiN are laminated in this order are formed inside the through hole, and then planarization by CMP is performed to form an interlayer connection plug (FIG. 4). (D)).

JP 2001-209191 A (FIG. 1, FIG. 2, Table 1)

  In such a conventional release agent composition, it is essential to contain (a) urea or a urea derivative and (b) a hydroxy aromatic as an anticorrosive agent. It is a component that keeps the anticorrosion function. As shown in FIG. 6, when urea is used alone, the anticorrosive property is poor, and the anticorrosive containing the component (a) such as urea may not function.

  Moreover, in order to fully exhibit the peeling function of a release agent composition, there exists a subject that it is necessary to maintain liquid temperature at about 80 degreeC, and the release agent composition which can be used at normal temperature was desired.

  Then, this invention solves the said conventional subject, and it aims at providing the peeling agent composition which can exhibit anticorrosion performance reliably at the normal temperature of about 20 degreeC, without using urea as an anticorrosion agent. To do.

  And, in order to achieve this object, the present invention comprises (a) an anticorrosive containing pyrogallol as an essential component, and (b) an alkanolamine, wherein the pH is adjusted to 8-10. Thus, an intended composition is achieved.

  Moreover, this invention contains the anticorrosive which has (a) pyrogallol as an essential component, (b) alkanolamine, (c) water-soluble polar solvent, (d) water, and adjusted pH to 8-10. The release agent composition is characterized by this.

  According to the present invention, when (a) an anticorrosive containing pyrogallol as an essential component and (b) an alkanolamine are included and the pH is adjusted to 8-10, b) The alkanolamine exhibits a peeling function, and the resist film and etching residue are removed. In addition, since the pH of acidic (a) pyrogallol and alkaline (b) alkanolamine is adjusted to maintain the pH at 8 to 10 at the time of mixing, by maintaining this pH value range, (a) pyrogallol Can strongly remove dissolved oxygen in the water, prevent the dissolved oxygen from reacting with the exposed metal surface such as copper film, and it is not necessary to coexist with urea or urea derivatives as an anticorrosive. In use, the effect of sufficiently exhibiting the anticorrosion function can be obtained.

  Furthermore, the release agent composition in which the components (a) and (b) are mixed has a pH in the weakly alkaline range of 8 to 10, and prevents generation of precipitates by preventing metal ions from becoming hydroxides. In addition, since the release agent composition can be used continuously without impairing the release function, the replacement frequency is reduced and an effect that the release treatment can be performed economically is obtained.

Sectional drawing of process of semiconductor substrate showing use of release agent composition of Embodiment 1 of the present invention Characteristic chart showing the relationship between pH value and dissolved oxygen concentration of pyrogallol Cross-sectional process diagram of a semiconductor substrate showing the use of a conventional release agent composition Cross-sectional process of semiconductor substrate showing other use of conventional release agent composition

  The release agent composition according to claim 1 of the present invention includes (a) an anticorrosive agent containing pyrogallol as an essential component, and (b) an alkanolamine, and has a configuration in which the pH is adjusted to 8 to 10. Thereby, when performing the stripping treatment, (b) the alkanolamine exerts the stripping function, the resist film and the etching residue are removed, and the pH of the stripping composition is kept at 8-10. Within this pH range, (a) pyrogallol can powerfully remove oxygen contained in moisture, thereby preventing oxygen from reacting with the exposed copper film and exhibiting an anticorrosive function.

  Moreover, (a) it contains the anticorrosive which has pyrogallol as an essential component, (b) alkanolamine, (c) water-soluble polar solvent, (d) It is set as the structure which adjusts pH to 8-10. Also good. As a result, (c) the water-soluble polar solvent melts the components (a), (c), and (d) and mixes them so that the pH value is uniform between 8 and 10, so that (a) oxygen of pyrogallol The removal force is exhibited stably, and the effect of maintaining the anticorrosion function is achieved.

  Further, (a) pyrogallol may be obtained by decomposing hydrolyzable tannin. Thereby, at the stage of producing the release agent composition, hydrolyzable tannin reacts with water (d) and decomposes to (a) pyrogallol, and thus exhibits the above-described anticorrosive function. In addition, (a) pyrogallol is produced when hydrolyzed tannin is dissolved in water, and this hydrolyzed tannin is contained in natural plants such as tea leaves and is easily degraded by microorganisms. Similarly, (b) alkanolamine has biodegradability, and the release agent composition in which the components (a) and (b) are mixed is easily decomposed by microorganisms, so that it can be easily disposed of. In addition, at the time of storage, there exists an effect that handling and acquisition are easy by managing the hydrolyzable tannin extracted from tea leaves etc. as a raw material.

  Moreover, the adjustment container which accommodates a hydrolyzable tannin and (b) alkanolamine each in a separate container, and adjusts pH to 8-10 when mixing both components of a hydrolyzable tannin and (b) alkanolamine at least. You may make it the structure called the peeling agent composition manufactured by. Thereby, an appropriate amount of the hydrolyzable tannin having a known pH is introduced into the adjustment container together with water to produce (a) pyrogallol, and (b) another container containing the alkanolamine having a known pH. An appropriate amount of the release agent composition can be obtained in the mixing vessel by adding an appropriate amount to the adjustment vessel and, if necessary, a pH adjuster or the like, so that an essential component of the release agent composition can be obtained. (A) The raw material storage before mixing of (b) component and the effect that pH adjustment at the time of mixing can be performed easily are produced.

  Further, by adopting monoethanolamine or N-methylaminoethanol as (b) alkanolamine, the peeling performance can be exhibited well.

  In addition, (c) dimethyl sulfoxide is used as the water-soluble polar solvent, so that not only organic substances but also inorganic compounds are dissolved well. Therefore, other release agent compositions of the present invention are mixed evenly, and release performance and anticorrosion performance are achieved. Good performance can be achieved.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

(Embodiment 1)
First, each component of the release agent composition described in claims 1 and 2 of the present invention will be described. (A) Pyrogallol is a trivalent phenol equivalent to 1,2,3-trihydroxylbenzene or 1,2,3-benzenetriol, and hydroxyhydroquinone and phloroglucin are isomers. (A) Pyrogallol is soluble in water and alcohol, has strong reducibility, and removes oxygen in a few seconds when it comes into contact with dissolved oxygen in water at room temperature in an alkaline solution region of pH 8 or higher. As a result, the dissolved oxygen contained in the release agent composition is strongly absorbed, so even if the release agent composition comes into contact with a metal surface such as a copper film, the metal surface is not oxidized and corroded. Anticorrosion function can be demonstrated.

  Thus, since the release agent composition of the present invention removes oxygen itself that causes oxidation and does not directly contact the metal surface, for all metals that can be oxidatively corroded, It effectively demonstrates the anticorrosion function.

  Moreover, (a) pyrogallol is produced when hydrolyzed tannin is dissolved in water, and this hydrolyzed tannin is contained in natural plants. For example, it is abundant in the wood part of chestnut, oak bark, tea leaves, miraboram fruit, Chinese quintuplet, etc. Can be stored.

  Examples of (b) alkanolamine include monoethanolamine, diethanolamine, N-ethylaminoethanol, N-methylaminoethanol, dimethylaminoethanol, 2- (2-aminoethoxy) ethanol, and this component is a release agent. The composition exhibits a peeling performance. In particular, monoethanolamine and N-methylaminoethanol are excellent in peeling performance.

  Further, as the (c) water-soluble polar solvent, it is preferable to use an organic solvent having miscibility with the components (a) and (b) and (d) water described later. The types include sulfoxides, sulfones, amides, lactams, imidazolidinones, lactones, polyhydric alcohols, etc. Among them, sulfoxide dimethyl sulfoxide is excellent in peelability and corrosion resistance. Yes.

Dimethyl sulfoxide is represented by the chemical formula CH ₃ —SO—CH ₃ and is easily mixed with water.
In addition, since it is highly polar and dissolves not only organic substances but also inorganic compounds well, it is good as a release agent composition of the present invention, but is not limited thereto, and is appropriately selected from the above-mentioned (c) water-soluble polar solvents. Can be used.

  (D) Water is an important component for mixing the above components (a) and (b) together with (c) the water-soluble polar solvent, and decomposes hydrolyzed tannin to produce (a) pyrogallol. And (a) an anticorrosive function of pyrogallol and (b) an alkanolamine peeling function.

  And manufacture of a release agent composition can be implemented by adjusting the pH in an adjustment container to 8-10 while mixing the hydrolyzable tannin and the (b) alkanolamine which were each accommodated in the separate container in the adjustment container. . That is, an appropriate amount from a container containing hydrolyzable tannin having a known pH is introduced into a control container together with water to produce (a) pyrogallol, and an appropriate amount from another container containing (b) alkanolamine having a known pH. Is added to the adjustment container, and (c) a water-soluble polar solvent and (d) water are added and mixed, and if necessary, a pH adjuster or the like is added to adjust the pH to 8 to 10 in the mixing container. A release agent composition can be obtained.

  At this time, the blending ratio of each component (a) to (d) is such that (a) component is 1 to 60% by mass, (b) component is 5 to 70% by mass, and (d) component is 2 to 40% by mass. It is suitable that the component (c) is in the range of the remaining mass%, but it is not limited to this condition, and the final release agent composition has a pH that falls within 8-10. That's fine. That is, this blending ratio may be changed in order to adapt to various conditions generated in the semiconductor substrate manufacturing process, and it is an essential condition that the pH of the stripping composition is within 8-10. is there.

  Next, as an application example of the release agent composition of the present invention, an example of using the release agent composition in the step of forming a copper wiring on a semiconductor substrate will be described. Since the process of forming the copper wiring is substantially the same as that shown in the prior art, the process different from the conventional example will be mainly described.

  As shown in FIG. 1A, after the etching process is completed, a part of the resist film 8 is removed by oxygen plasma ashing, and then a stripping process is performed using the stripping composition of the present invention. By this peeling process, the resist film 8a and the etching residue 11 are removed. At this time, although the copper film 5 is exposed in a part of the through holes 10, it contains (a) an anticorrosive containing pyrogallol as an essential component, and (b) an alkanolamine, and the pH is adjusted to 8 to 10. By using the stripping composition, since the dissolved oxygen does not touch the copper film 5, the resist film 8a and the etching residue 11 can be removed without causing damage such as corrosion.

  Further, in the next step shown in FIG. 1B, when etching the silicon nitride film 6 by changing the etching gas, even if the etching residue 12 adheres to the inner wall of the through hole 10, it was used first. If the stripper composition is within the range of pH 8 to 10, (a) pyrogallol can maintain the ability to remove dissolved oxygen and exhibit an anticorrosive function, and therefore this stripper composition can be used continuously and repeatedly. it can.

  Next, in the characteristic diagram of the dissolved oxygen concentration shown in FIG. 2, (a) measuring the change in the dissolved oxygen concentration due to the change in pH value using the concentration of the solution containing hydrolyzable tannin as the source of pyrogallol as a parameter (A) It is verified that the release agent composition containing pyrogallol is effective at a pH value of 8 or more.

  2 (a) to 2 (c) show three types of solutions obtained by adding 0.1% by mass, 0.5% by mass, and 1.0% by mass of hydrolyzable tannin to 200 cc of pure water, respectively. FIG. 5 is a characteristic diagram showing the relationship between pH value and dissolved oxygen concentration (mg / l). The dissolved oxygen concentration is a value measured by a DO meter, and the water temperature during measurement is 20 ° C. to 22 ° C. at room temperature. Further, what is shown in FIG. 2 (d) is a confirmation test conducted by raising the pH value to 12 under the same measurement conditions as in FIG. 2 (c).

  And comparing each characteristic diagram, since what is shown in FIG. 2 (a) is low at a hydrolyzable tannin content of 0.1% by mass, the dissolved oxygen concentration is 1.5-6 mg / l at pH 8-10. And shows a high value. However, as shown in FIGS. 2B to 2D, when the content of hydrolyzable tannin is increased to 0.5% by mass or more, the dissolved oxygen concentration decreases to 0 mg / l or the vicinity thereof. This indicates that (a) pyrogallol produced by the decomposition of hydrolyzable tannin reliably removes dissolved oxygen in the liquid if the pH is 8 or higher.

  Moreover, what is shown in FIG.2 (e) measured transition of a dissolved oxygen concentration when 1.0 mass% of hydrolyzable tannins were added with respect to 200cc of solutions which set pH value to 8.6. It is. This measurement result shows that the dissolved oxygen concentration in the solution of 6.3 mg / l rapidly decreases to 0 mg / l between 120 seconds and 180 seconds, and deoxygenates in a short time. Furthermore, the subsequent process maintains the deoxygenated state.

  Thus, at pH 8-10, (a) pyrogallol can remove the dissolved oxygen in the liquid in a short time and maintain a deoxygenated state. Therefore, (a) pyrogallol is an essential component. The release agent composition can be proved to exhibit an anticorrosion function by preventing oxygen from directly contacting the metal surface.

  Therefore, as in the present invention, (a) an anticorrosive agent containing pyrogallol as an essential component, and (b) a release agent composition containing alkanolamine and having a pH adjusted to 8 to 10 (b) Exhibits the peeling function of alkanolamine and (a) pyrogallol strongly removes oxygen contained in the liquid, preventing oxygen from reacting with the exposed metal surface such as copper film, and ensuring anticorrosion function It can be demonstrated to.

  Further, a release agent composition containing (a) an anticorrosive agent containing pyrogallol as an essential component, (b) an alkanolamine, (c) a water-soluble polar solvent, (d) water, and adjusting the pH to 8 to 10. (C) Since the water-soluble polar solvent melts the components (a), (c) and (d) and mixes them so that the pH value is uniform between 8 and 10, (a) pyrogallol It is possible to stably exhibit the oxygen-removing power.

  Since the release agent composition according to the present invention is a release agent that exerts a strong anticorrosion function by removing oxygen strongly, expensive and rare metals such as decorative precious metals and finely processed metal jewelry Useful as a cleaning agent.

5 Copper film 6 Silicon nitride film 8 Resist film 8a Resist film 10 Through hole 11 Etching residue 12 Etching residue

Claims (6)

(A) an anticorrosive agent containing pyrogallol as an essential component;
(B) contains an alkanolamine,
A release agent composition having a pH adjusted to 8 to 10. (A) an anticorrosive agent containing pyrogallol as an essential component;
(B) an alkanolamine;
(C) a water-soluble polar solvent;
(D) contains water,
A release agent composition having a pH adjusted to 8 to 10. (A) Pyrogallol is obtained by decomposing hydrolyzable tannins, The stripping composition according to claim 1 or 2. The hydrolyzable tannin and (b) alkanolamine are stored in separate containers, respectively, and at least when the hydrolyzable tannin and (b) alkanolamine are mixed, the hydrolyzable tannin and the alkanolamine are manufactured by adjusting means for adjusting pH to 8-10 The release agent composition according to claim 3. (B) The stripping composition according to any one of claims 1 to 4, wherein the alkanolamine is monoethanolamine or N-methylaminoethanol. (C) The stripping composition according to claim 2, wherein the water-soluble polar solvent is dimethyl sulfoxide.

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