JP2875553B2 - Method for Preventing Oxidation-Reduction Reaction Occurrence and Processing Apparatus Used Therefor - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a method for preventing the occurrence of a redox reaction and a processing apparatus used for the method, and in particular, two or more different conductive films are electrically connected to each other. The present invention relates to a method for preventing the occurrence of an oxidation-reduction reaction suitable for improving the yield during the manufacture of a device having a structure, and a processing apparatus used for the method.

[Conventional technology]

A typical example of a process including an operation of immersing a multilayer film including at least two or more different conductive films in an alkaline solution includes a photolithography process used for manufacturing ICs, thin film transistors, and the like. This step is
For example, "Super LSI Technology" (Souken Shuppan) 278-28
As described in item 3, the method includes the steps shown in FIG. 5 and the following description. That is, (a) a step of forming a resist layer 4 on a workpiece 15 formed on a substrate 1, (b) a step of exposing the resist 4 to light by irradiating the resist 4 with light through a mask 5, and (c). Developing the substrate obtained in (b) using a developing device comprising a developing tank 6 and a developing solution 7 shown in (c ') to obtain a predetermined resist pattern; and (d) etching a substance to be processed by etching. And (e) stripping the resist 4.

Here, the step of immersing the multilayer film in an alkaline solution is the step (c). As the developing solution 7, an alkaline solution having a pH of 12 to 13 is widely used. As shown in FIG. 6A, the developing device of FIG.
Is filled with the developing solution 7, and the substrate 1 to be processed is immersed in the developing device, and the developing device 7 is sprayed from the nozzle 16 onto the substrate 1 as shown in FIG. There is a spray device for developing.

[Problems to be solved by the invention]

Here, an ITO (Indium Tin Oxide) film made of an oxide of indium (In) and tin (Sn) and an aluminum (A)
l) Problems of the prior art will be described by taking, as an example, a case where a substrate having a structure electrically connected to a film is immersed in an alkaline developer.

When the electrically connected ITO film and Al film come into contact with an alkaline solution, a difference in ionization tendency causes a potential difference between the two films, causing the Al to be oxidized and the ITO to be reduced. However, due to this phenomenon, oxygen in the ITO film is released, causing problems such as a decrease in the transmittance of the ITO film and an increase in resistance. Further, when the reduction reaction further proceeds, metal powder of In or Sn precipitates, the surface irregularities become severe, and the film thickness becomes thin. In addition, since the deposited metal powder only adheres to the substrate, there is a problem that the metal powder is easily peeled off by washing with water or the like.

SUMMARY OF THE INVENTION An object of the present invention is to provide a method for preventing the occurrence of a redox reaction which occurs when two or more electrically conductive films which are electrically connected to each other are brought into contact with an alkaline solution. , And a processing apparatus used for implementing the method.

[Means for solving the problem]

The above object can be achieved by adding an oxidizing agent to the alkaline solution used for the treatment. Here, as the oxidizing agent, oxygen, ozone, aqueous hydrogen peroxide, ammonium bichromate, and sodium hypochlorite are effective.

[Action]

By adding the oxidizing agent to the alkaline solution, it is possible to suppress the occurrence of the oxidation-reduction reaction occurring between the two or more different conductive films described above, and to damage the conductive film caused by the progress of the reaction, Deterioration and the like can be prevented.

〔Example〕

Hereinafter, the method for preventing the occurrence of the oxidation-reduction reaction of the present invention and the processing apparatus used for the method will be specifically described with reference to examples.

Embodiment 1 An embodiment in which the method for preventing the occurrence of an oxidation-reduction reaction according to the present invention is applied to a photolithography step will be described with reference to FIG.

That is, the photolithography process using the method for preventing the occurrence of a redox reaction of the present invention comprises the steps of: (a) forming a resist 4 on a substrate 1 on which a multilayer film in which an ITO film 2 and an Al film 3 are electrically connected is laminated; Coating step (b) on the substrate 1 obtained in (a) via a mask 5
(C) exposing the resist 4 to light, and (c) introducing a gas 8 containing oxygen into a developing tank 6 filled with a developing solution 7 shown in (c ′). The present invention comprises the steps of: developing using a developing device to obtain a predetermined resist pattern; (d) processing the Al film 3 into the same shape as the resist pattern by etching; and (e) removing the resist. The method and the processing apparatus are applied to the step (c).

Here, an example of the developing device shown in (c ') will be described with reference to FIG. 2. This device comprises a preliminary tank 10 filled with a developer 7, a bubbler 13 for generating fine bubbles, and a preliminary tank. A system consisting of an ultrasonic device 12 for vibrating 10 and
It comprises a developing tank 6 and a pump 11. Also,
The preliminary tank 10 contains fine bubbles 9 containing oxygen via a bubbler 13.
The foam 9 is further finely foamed by the ultrasonic device 12. Thus, the developing solution 7 containing a large amount of oxygen is transferred to the main body of the developing tank 6 by the pump 11.

FIG. 1 (e) shows an example in which a developer prepared by mixing oxygen with a solution 30 prepared by mixing a 1: 1 alkali developer (trade name: DE-3) manufactured by Tokyo Ohka Co., Ltd. )
When the substrate having the structure in which the ITO film 2 and the Al film 3 were electrically connected was immersed, no oxidation-reduction reaction occurred, and no defects were found in both films.

Similar results were obtained when ozone was used instead of oxygen.

Embodiment 2 FIG. 3 shows an example of a developing apparatus using a spray of a developing solution containing oxygen or a gas containing oxygen as a processing apparatus used for carrying out the method of the present invention.

The apparatus comprises a nozzle 16, a developing solution 7, a reserve tank 10 for storing the developing solution 7, and a gas 8 containing oxygen or oxygen. Further, oxygen or gas 8 containing oxygen is also sent to the nozzle 16, mixed with the developing solution 7 and sprayed from the nozzle 16 onto the substrate 1.

When a substrate having the structure shown in FIG. 1 (e) is processed using the above apparatus and a mixed solution of DE-3: water = 1: 1 as a developing solution and oxygen as a gas, an oxidation-reduction reaction occurs. IT by
No defects were found in the O film or Al film.

Embodiment 3 An example in which a substance other than oxygen or ozone is used as an oxidizing agent added to an alkaline solution will be described with reference to FIG.

The developing tank 6 was filled with a developing solution 7 in which 1 ml of hydrogen peroxide solution, 4 ml of sodium hypochlorite or 2 g of dichromic acid was added to the liquid 1 prepared as DE-3: water = 1: 1, and FIG. When the substrate 1 having the structure shown in (1) was immersed, no oxidation-reduction reaction occurred and there was no damage to the film. Further, the developability of the developer at this time was exactly the same as that when the oxidizing agent was not added. Similar results were obtained when the above-mentioned mixed solution was used in a developing device by a spray method.

In the above embodiment, the conductive film is made of an Al film and an ITO film.
Although an example in which the film and the alkaline solution are a developer is described, similar results were obtained when the film and the alkaline solution were applied to an alkaline solution such as a stripper or a cleaning solution.

〔The invention's effect〕

As described above, when two or more different electrically conductive films that are electrically connected to each other are brought into contact with an alkaline solution, by taking measures for adding an oxidizing agent to the alkaline solution, the conventional technology can be used. To solve the problem
A method for preventing the occurrence of an oxidation-reduction reaction and a processing apparatus therefor can be provided. As a result, in the manufacture of a device having a structure in which two or more different conductive films are electrically connected, the manufacturing yield can be improved.

[Brief description of the drawings]

FIG. 1 is a view showing a procedure of a photolithography step using the method for preventing the occurrence of an oxidation-reduction reaction according to the present invention, and FIG. 2 is a processing apparatus of the present invention having a mechanism for introducing a gas containing oxygen into a developer (immersion). FIG. 3 is a view showing the structure of a developing apparatus by a spray method, FIG. 3 is a view showing the structure of a processing apparatus of the present invention (developing apparatus by a spray method) provided with a mechanism for introducing a gas containing oxygen into a developing solution, and FIG. FIG. 5 is a view showing the configuration of a processing apparatus of the present invention (developing apparatus using an immersion method) when an oxidizing agent other than oxygen or ozone is added to a developing solution. FIG. 5 is a view showing a conventional photolithography process, and FIG. FIG. 1 is a diagram showing a configuration of a processing device (developing device) according to the related art. DESCRIPTION OF SYMBOLS 1 ... Substrate 2, 2 ... ITO film 3 ... Al film, 4 ... Resist 5 ... Mask, 6 ... Development tank 7 ... Development liquid, 8 ... Gas 9 ... Bubbles, 10 ... Preliminary tank 11 Pump, 12 Ultrasonic device 13 Bubbler, 14 Oxidizing agent 15 Work material, 16 Nozzle

──────────────────────────────────────────────────続 き Continuing from the front page (72) Inventor Takao Takano 292, Yoshida-cho, Totsuka-ku, Yokohama-shi, Kanagawa Prefecture Inside the Manufacturing Research Laboratory, Hitachi, Ltd. (72) Mitsuo Nakatani 292, Yoshida-cho, Totsuka-ku, Yokohama, Kanagawa Prefecture Stock (72) Inventor Yoshifumi Tomita 3300 Hayano, Mobara-shi, Chiba Prefecture Inside Mobara Plant, Hitachi, Ltd. (72) Inventor Akira Sasano 3300, Hayano, Mobara-shi, Chiba Prefecture Mobara Plant, Hitachi, Ltd. (72) Inventor Hideaki Taniguchi 3300 Hayano, Mobara City, Chiba Pref. Inside the Mobara Plant, Hitachi, Ltd. (56) References JP-A-63-284824 (JP, A) JP-A-2-310381 (JP, A) JP-A-1-151237 (JP, A) JP-A-59-104132 (JP, A) JP-A-64-55926 (JP, U) (58) t.Cl. ^6, DB name) H01L 21/306 - 21/3063 H01L 21/308 H01L 21/027 H01L 21/304 H01L 21/3205 H01L 21/321 H01L 21/28 - 21/288 H01L 21/44 - 21/445 C23F 1/00-3/06

Claims (5)

(57) [Claims] 1. An oxidation-reduction reaction of said conductive film which occurs through said alkaline solution when at least two or more different conductive films are brought into contact with said alkaline solution in a state of being electrically connected to said alkaline solution. A method for preventing the occurrence of an oxidation-reduction reaction, characterized in that the oxidation-reduction reaction is reduced by adding an oxidant. 2. The method according to claim 1, wherein one of the two or more different conductive films is a transparent conductive film mainly containing indium and tin oxide, and the other is a metal film mainly containing aluminum. The method for preventing occurrence of an oxidation-reduction reaction according to claim 1. 3. The method according to claim 1, wherein said alkaline solution is a photoresist developing solution, a photoresist stripping solution or an alkaline cleaning solution. 4. The method according to claim 1, wherein said oxidizing agent is at least one of oxygen, ozone, aqueous hydrogen peroxide, ammonium bichromate, and sodium hypochlorite. The method for preventing the occurrence of the oxidation-reduction reaction as described above. 5. An apparatus for performing treatment by bringing at least two or more different conductive films into contact with an alkaline solution in an electrically connected state, comprising a mechanism for adding an oxidizing agent to the alkaline solution. A processing apparatus used for implementing a method for preventing the occurrence of a redox reaction.