JP2002348663A - Mg sputtering target for forming MgO thin film with low particle generation - Google Patents

Abstract

An object of the present invention is to provide an Mg sputtering target used when manufacturing an MgO thin film as a protective film of a dielectric layer in an AC type plasma display panel by a reactive sputtering method. An inclusion existing in a Mg base has a maximum diameter of 5 mm.
An Mg sputtering target for forming an MgO thin film having a small particle size of 1 mm or less (preferably 1 mm or less).

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a protective film for a dielectric layer in an AC plasma display panel.
The present invention relates to a Mg sputtering target used when producing a gO thin film by a reactive sputtering method.

[0002]

2. Description of the Related Art Generally, an MgO thin film is used as a protective film for a dielectric layer in an AC type plasma display panel. This MgO thin film is usually formed by vapor deposition. Attempts have been made to form them by sputtering (see JP-A-10-130828). However, the MgO target has poor sinterability due to the high melting point of MgO,
Therefore, it is difficult to obtain a sintered body having sufficiently high density and high strength. Therefore, in general, the MgO sputtering target has low density and strength, and high-speed film formation is difficult because high-power high-speed film formation using this low-density and strength MgO sputtering target causes cracks. Therefore, in recent years, in order to form an MgO thin film by sputtering, an attempt has been made to form a MgO thin film by performing reactive sputtering in an inert gas atmosphere containing a small amount of oxygen using a sputtering target made of metallic Mg. I have.

[0003]

However, the conventional metal M
When reactive sputtering is performed using a Mg sputtering target consisting of g, particles adhere to the obtained MgO thin film due to the occurrence of abnormal discharge, and, in severe cases, glow discharge becomes unstable due to the abnormal discharge, In some cases, stable sputtering cannot be performed.

[0004]

Means for Solving the Problems Accordingly, the present inventors have:
When abnormal discharge thus particles in forming by reactive sputtering an MgO thin film was conducted research to obtain a less Mg sputtering target be generated, CaCl ₂ present in the matrix of Mg sputtering target, MgCl _2, KCl etc. The size of the inclusions greatly affects the abnormal discharge and thus the generation of particles. If the maximum diameter of these inclusions exceeds 5 mm, the abnormal discharge and thus the particles are generated. 5mm diameter
The research result said that it was necessary to limit to below (preferably 1 mm or less).

[0005] The present invention has been made based on the results of such research, and has been made to form an MgO thin film having a maximum particle diameter of 5 mm or less (preferably 1 mm or less) and a small number of particles, which are present in the Mg base. Mg sputtering target for use.

A conventional Mg sputtering target is:
It is manufactured by molding a commercially available Mg ingot with a small amount of inclusions into a target shape.
g Ingots are manufactured by the Durville-type casting method or the semi-continuous casting method. However, the Mg sputtering target of the present invention uses the above-mentioned Durbil-type casting method or semi-continuous casting method to eliminate inclusions having a maximum diameter exceeding 5 mm. The ingot obtained by the above is further redissolved at least once by a Durville type casting method or a semi-continuous casting method, and the ingot obtained by the remelting is formed into a target shape. The number of times of re-dissolution is determined by examining inclusions contained in a commercially available ingot and determining the amount thereof.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION A commercially available metallic Mg ingot was prepared, and the presence or absence of an inclusion was measured by an ultrasonic flaw detection method. As a result, a large inclusion having a maximum diameter of 5 mm or more was present.

Example 1 A commercially available metallic Mg ingot was remelted three times by a semi-continuous casting method to produce a metallic Mg ingot, and the metallic Mg ingot was subjected to ultrasonic flaw detection to determine the presence or absence of inclusions. Maximum inclusion: no large inclusions exceeding 1 mm were present. The thus obtained metal Mg ingot was formed into a size having a diameter of 127 mm and a thickness of 15 mm to produce a target 1 of the present invention.

Example 2 This commercially available metal Mg ingot was redissolved once by a semi-continuous casting method to produce a metal Mg ingot, and the metal Mg ingot was subjected to ultrasonic flaw detection to determine the presence or absence of inclusions. No large inclusions exceeding the maximum diameter: 5 mm were present, but inclusions within the maximum diameter: 1 to 5 mm were present. The thus obtained metal Mg ingot was formed into a size having a diameter of 127 mm and a thickness of 15 mm to prepare a target 2 of the present invention.

Conventional Example 1 The commercially available metallic Mg ingot was used as it was, and had a diameter of:
A conventional target was manufactured by molding to a size of 127 mm and a thickness of 15 mm.

Examples 1 and 2 and a conventional target were attached to a DC magnetron sputtering apparatus, and sputtering was performed for 35 hours under the following conditions: DC power: 800 W, Ar pressure: 5 mTorr, oxygen pressure: 50 μTorr, and the number of arcs generated was examined. The results shown in Table 1 were obtained. In this case, the arc immediately after the start of sputtering is due to contamination or oxides on the target surface and may be ignored.

[0012]

[Table 1]

[0013]

From the results shown in Table 1, Examples 1 to 2
In the target of the present invention manufactured in the above, since the number of times of arc generation is much smaller than that of the conventional target manufactured in Conventional Example 1, it can be seen that the number of particles generated at the time of sputtering is significantly smaller, and Excellent effects such as the yield can be further improved.

Claims (2)

[Claims] 1. The method according to claim 1, wherein the inclusions present in the Mg base have a maximum diameter of 5
mm or less, the Mg sputtering target for forming an MgO thin film with less generation of particles. 2. Inclusions existing in the Mg base have a maximum diameter of 1
mm or less, the Mg sputtering target for forming a MgO thin film with less generation of particles.