JPH05230623A - Majufacture of oxidation resistant protective film - Google Patents

Abstract

PURPOSE:To provide the method for manufacturing an oxidation resistant protective film excellent in oxidation resistance, inexpensively manufacturable and, furthermore, easily removable. CONSTITUTION:This is the method for manufacturing an oxidation resistant protective film in which an oxidation resistant protective film is formed by vapor-depositing metal on the surface of a substrate 1, and at least either of the condition in which the oxide of the metal has value smaller than that of the oxide of the substrate in the absolute value of standard generating free energy at a room temp. and the condition in which the oxide of the metal has value higher than that of the oxide of the substrate 1 in decomposing energy at a room temp. is satisfied.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of manufacturing an oxidation resistant protective film.

[0002]

2. Description of the Related Art When forming a film, there are, for example, a chemical vapor deposition method (CVD method) and a physical vapor deposition method (PVD method). Each of these methods has its own characteristics. In general, the CVD method has a high film deposition rate and good throwing power, but on the other hand, the type of the substrate is limited because the film is formed while heating the substrate, and it was exposed to high temperatures. Sometimes the substrate is damaged. On the other hand, the vacuum vapor deposition method, which is a type of PVD method, can form a film without exposing the substrate to high temperatures, but the adhesion is inferior to the CVD method. Therefore, these methods are properly used according to the type of the substrate, the purpose of the film to be attached, and the like.

When a multilayer film is formed by combining such film forming processes, it may be necessary to use a plurality of thin film forming apparatuses. At this time, finish the previous process,
The sample must be exposed to the atmosphere when moving to the next step. At this time, the treated surface of the substrate is oxidized, polluted in the air,
There is a risk of being corroded and adversely affecting the properties of the treated surface and of the film produced on it.

In order to avoid this, when a multilayer film is formed by using a plurality of thin film forming apparatuses, the surface to be processed is oxidized even when the sample is exposed to the atmosphere when the process moves from the previous process to the next process. Form a protective film to prevent contamination and corrosion. In other words, on the surface of the substrate that has been treated in the previous step,
A protective film is formed in the same chamber without exposing this substrate to the atmosphere. After that, before performing the next step in the thin film forming apparatus for performing the next step, the protective film is removed and the process is started. Through such a process, even if the sample is exposed to the atmosphere, the treated surface of the sample is not oxidized, contaminated or corroded.

This oxidation resistant protective film has been conventionally formed by an ion plating method or a CVD method.

[0006]

However, in the ion plating method or the CVD method, the cost is high when the protective film is formed, and the adhesion of the formed protective film is high, so that the removal is not easy and the removal is difficult. It causes considerable damage to the surface of the substrate. Further, the CVD method has a drawback that hydrogen remains in the film and the hydrogen forms a dangling bond, which attracts oxygen and is easily oxidized.

Therefore, an object of the present invention is to provide a method of manufacturing an oxidation resistant protective film which has excellent oxidation resistance, can be manufactured at low cost, and can be easily removed.

[0008]

The method for producing an oxidation-resistant protective film according to the present invention comprises depositing a metal on the surface of a substrate to form an oxidation-resistant protective film on the surface of the substrate. A method for producing a film, which comprises a condition that the oxide of the metal has a value smaller than that of the substrate in an absolute value of standard free energy of formation, and the oxide of the metal causes oxidation of the substrate at a decomposition energy. It is characterized in that at least one of the conditions having a value larger than that of the object is satisfied.

[0009]

The method of manufacturing the oxidation resistant protective film according to the present invention will be described with reference to FIG.
The device shown in FIG. That is, 1 is silicon (S
A substrate such as i), 2 is an evaporation source, 3 is a metal as an evaporation material, and these are provided in a vacuum container (not shown).
The metal 3 is vaporized by the vaporization source 2, is made to fly to the surface of the substrate 1, and is vapor-deposited as shown in FIG.
Since the oxidation resistant protective film 4 thus formed is formed by vapor deposition, the cost can be reduced as compared with the conventional example. Further, since the particle energy is small, the substrate 1
Since the damage to the surface of the substrate is minimized and the adhesion is low, the substrate 1 can be easily removed in both the dry process and the wet process without damaging the substrate 1.

On the other hand, the surface of a metal is oxidized when exposed to the atmosphere, and depending on the material, oxygen diffuses in the metal film and reaches the surface of the substrate 1. However, the type of metal is, for example, a condition that the standard free energy of formation of the oxide of the metal is smaller in absolute value than that of the substrate (Si) at room temperature, or the decomposition energy of the oxide of the metal is at room temperature. By applying conditions satisfying at least one of the conditions having a larger value, that is, one or both of the conditions, it is possible to prevent oxidation of the substrate 1 and improve the oxidation resistance. ..

That is, first, the absolute value of the standard free energy of formation is smaller than that of the substrate 1. The larger the standard free energy of formation, that is, the smaller the absolute value, the more the metal is oxidized than the substrate 1. This is because it is difficult to form things. Therefore, an oxide of a metal satisfying this condition serves as the oxidation resistant protective film 4, which makes the substrate 1 excellent in oxidation resistance.

The condition that the decomposition energy has a value larger than that of the substrate 1 is that the larger the decomposition energy than the substrate 1, the more chemically stable the oxide formed, so that the oxide layer is a barrier. This is because it plays the role of a layer and suppresses the invasion of oxygen from the surface layer. Therefore, a metal satisfying this condition also has excellent oxidation resistance of the substrate 1.

[0013]

EXAMPLE A Si wafer is pretreated by HF rinse,
After cleaning the surface with Ar ions, a Cu film,
A Si film, a Ti film, and an Al film are formed by a vacuum deposition method,
3 different thicknesses for each: 300Å, 50
A substrate 1 having a metal film of 0Å and 1000Å was formed. By the same method, a substrate 1 of Ni film and Fe film having a thickness of 300Å and 500Å was formed.

After leaving these samples in the atmosphere for about 4 weeks, the depth of oxygen penetration from the surface layer was determined by Auger electron spectroscopy. This oxygen penetration depth and room temperature (29
These oxides (2CuO, 2Cu ₂ O, 2NiO, 2Fe at 8K)
O, 2 / 3Fe ₂ O ₃ , 1 / 2Fe ₃ O ₄ , SiO ₂ , TiO ₂ , 2TiO, 2 / 3Al ₂ O ₃ ) standard free energy of formation ΔGf is shown in FIG. 3 at room temperature (298K). FIG. 4 shows the relationship between the penetration depth of oxygen and the decomposition energy of oxides. In the figure, ○ indicates a film thickness of 30.
0Å, △ mark is film thickness 500Å, square mark is film thickness 1000
The metal film of Å is shown.

As is clear from FIG. 3, Cu, Ni, F
e oxide (2CuO, 2Cu ₂ O, 2NiO, 2FeO, 2 / 3Fe ₂ O ₃ , 1 / 2Fe
₃ O ₄ ) standard free energy of formation is the oxide (Si
The penetration depth of oxygen from the surface layer is smaller than that of O ₂ ), which means that the penetration depth of oxygen from the surface layer is small due to the property that the metal is less likely to form an oxide than the substrate 1. It can be seen that it is excellent as an oxidation resistant protective film.

As is apparent from FIG. 4, Ti, Al
The decomposition energy of the oxide (TiO ₂ , 2TiO, 2 / 3Al ₂ O ₃ ) is larger than that of the oxide (SiO ₂ ) of the substrate 1, and the penetration depth of oxygen from the surface layer is small. This is because the formed oxide is chemically stable, and the oxide layer plays the role of a barrier layer and suppresses the invasion of oxygen from the surface layer, indicating that it is excellent as an oxidation resistant protective film. ..

[0017]

The method for producing an oxidation resistant protective film according to the present invention has a condition that the oxide of the metal has a smaller value than the oxide of the substrate in the absolute value of standard free energy of formation at room temperature, and Since the metal is selected which satisfies at least one of the conditions that the oxide of the metal has a larger value than the oxide of the substrate in the decomposition energy at room temperature, it has excellent oxidation resistance, can be manufactured at low cost, and can be removed. The effect is that an oxidation resistant protective film can be easily formed.

[Brief description of drawings]

FIG. 1 is an explanatory view of a thin film forming apparatus for carrying out a method of manufacturing an oxidation resistant protective film according to the present invention.

FIG. 2 is a schematic side view of a substrate.

FIG. 3 is a graph of the penetration depth of oxygen from the surface layer with respect to the standard energy of formation of oxide.

FIG. 4 is a graph of penetration depth of oxygen from the surface layer with respect to decomposition energy.

[Explanation of symbols]

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Akinori Ebe, 47 Umezu Takaune-cho, Ukyo-ku, Kyoto City, Nissin Electric Co., Ltd. (72) Inventor Taizo Okazaki, 47 Umezu-Takaune-cho, Ukyo-ku, Kyoto City, Nissin Electric Co., Ltd.

Claims (1)

[Claims] 1. A method for producing an oxidation resistant protective film, which comprises forming an oxidation resistant protective film on the surface of a substrate by vapor-depositing a metal on the surface of the substrate, wherein the standard free energy of formation is the absolute value. Satisfying at least one of a condition that the metal oxide has a value smaller than that of the base oxide and a condition that the metal oxide has a larger value in decomposition energy than the base oxide. A method for producing an oxidation-resistant protective film, which is characterized.