JP4474015B2 - Sputtering equipment for insulator production - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an apparatus for producing an insulator by sputtering on an electronic component or the like of a semiconductor or a magnetic head.
[0002]
[Prior art]
Conventionally, as a sputtering apparatus used for manufacturing an insulator, for example, a substrate c such as a silicon wafer, a cathode electrode d, and a film deposition chamber b evacuated by a vacuum pump a as shown in FIG. The thing of the structure which provided the target e for insulator formation on this electrode d is known. When an alumina insulator is formed on the substrate c by RF sputtering, an aluminum target e is prepared, the electrode d is connected to a high frequency power source, and the film forming chamber b is connected to gas introduction pipes j and f. Argon gas and oxygen gas are introduced. The aluminum particles sputtered by ions from the plasma generated in front of the electrode d react with oxygen gas to become alumina and deposit on the substrate c. The pressure in the film forming chamber b is measured by an ionization vacuum gauge g. In order to prevent sputter particles from adhering to the inner wall of the film forming chamber b, an adhesion preventing plate h is provided in front of the inner wall, and the film forming chamber b and the adhesion preventing plate h are grounded and configured as an anode. . i is a substrate stage.
[0003]
[Problems to be solved by the invention]
If the production of the insulator is continued by sputtering as described above, the plasma generation state begins to be different from the production start time. Specifically, the difference starts from the point in time when a total thickness of several μm or more is formed on the substrate c. This is because the surface of the anode necessary for the generation and maintenance of discharge by the cathode electrode d becomes insufficient due to the adherence of the insulator to the deposition preventing plate h, the cathode electrode d, the substrate stage i, and the like. is there. The plasma moves toward a surface in the film formation chamber b where no insulator is attached in search of an anode necessary for discharge, and begins to take a form different from the initial form. As a result, the characteristics of the manufactured insulator are different from the initial one, which is not preferable for quality control.
[0004]
Conventionally, in such a case, in order to recover the initial state, the operation is stopped, the deposition preventing plate h is replaced, and maintenance of the sputtering apparatus such as the surface treatment of the inner wall of the film forming chamber is performed. However, in the past, the time when maintenance should be performed is not clear, and it is determined by time management, or maintenance is performed after an abnormality occurs in the characteristics of the manufactured insulator. There are inconveniences such as lowering the operation efficiency or causing product defects.
[0005]
It is an object of the present invention to provide an apparatus in which a clear maintenance time of a sputtering apparatus for producing an insulator is known and product defects are not generated.
[0006]
[Means for Solving the Problems]
In the present invention, an apparatus for preparing an insulator by providing a substrate, a cathode electrode, and an insulator forming target in a vacuum evacuated deposition chamber, and depositing particles sputtered from the target on the substrate. An adhesion preventing plate is provided in front of the inner wall of the film forming chamber to prevent scattering of the insulator, and the state of plasma generation that diffuses into the space between the inner wall of the film forming chamber and the adhesion preventing plate is determined by the electrode. The above purpose was achieved by monitoring. The electrode can be composed of an ionimeter ion collector.
[0007]
DETAILED DESCRIPTION OF THE INVENTION
Referring to the drawings, an embodiment of the present invention will be described. In FIG. 2, reference numeral 1 denotes a film forming chamber evacuated by a vacuum pump 2, and an upper RF power source or the like is provided in the film forming chamber 1. And a substrate stage 5 on which a substrate 4 such as a silicon wafer is placed. Reference numeral 6 denotes an insulator forming target attached to the cathode electrode 3, 7 denotes a gas introduction pipe for introducing a sputtering gas such as argon gas, and 8 denotes a gas introduction pipe for introducing a reactive gas such as oxygen gas. The film forming chamber 1 is provided with a pressure gauge 9 such as an ionization vacuum gauge in order to measure the pressure in the film forming chamber 1 before starting sputtering, and in front of the inner wall of the film forming chamber 1, An adhesion preventing plate 10 for preventing the inner wall from being contaminated with sputtered particles or the like is detachably provided. When an insulator having a predetermined thickness is formed on the substrate 4, the substrate 4 is transferred into and out of the film forming chamber 1 by appropriate loading / unloading means.
[0008]
Such a configuration is not particularly different from the conventional one, and an aluminum target 6 is prepared, the inside of the film forming chamber 1 is evacuated, and argon gas and oxygen gas are introduced from the gas introduction pipes 7 and 8, respectively. Sputtering power is applied to the cathode electrode 3 to generate a plasma 11 in front of the target 6, and aluminum particles sputtered by ions incident on the target 6 react with oxygen gas to form an alumina insulator on the substrate 4. However, when the total thickness of the insulator formed on the substrate 4 exceeds 1 to 2 μm as described above, the plasma generation state becomes abnormal, and the film thickness distribution And the reproducibility of characteristics such as film stress are deteriorated. This abnormality in the plasma state is due to the adhesion of an insulator to the anode deposition plate 10 or the inner wall of the film forming chamber 1, and in a normal state where an insulator with good reproducibility can be produced, as shown in FIG. In the state in which the plasma 11 is localized in front of 3 but an insulator with poor reproducibility is produced, it spreads toward the back surface of the deposition prevention plate 10 and the exhaust port, for example, as shown in FIG. It turned out to be sought. The state of deformation differs depending on the material of the insulator, the internal structure of the film forming chamber 1, and the like.
[0009]
In order to detect such a plasma abnormality, in the present invention, an electrode 12 for monitoring the generation state of the plasma 11 is provided in the film forming chamber 1, and the abnormal spread of the plasma 11 is detected by a change in the detected ion current. , And the maintenance for removing the insulator in the film forming chamber 1 can be performed. The electrode 12 may be any electrode that can detect an ion current, such as an ion collector of a known ionometer, and is provided at a position where the plasma 11 moves and an abnormality is detected. An ion current caused by plasma that is provided in a space between the inner wall of the membrane chamber 1 and diffuses there is detected. The detected ion current value varies depending on the insulator to be manufactured and the type of the substrate, and thus cannot be generally stated. However, in the illustrated example, the ion current is 1 nA or less at the time when an insulator with good reproducibility can be manufactured. When the ion current exceeds 1 nA, the plasma starts to move as shown in FIG. 3, and the reproducibility starts to deteriorate at this time. Therefore, in the embodiment, when the ion current exceeds 1 nA, the operation of the apparatus is stopped, and the protection plate 10 is replaced and the inner wall is cleaned. Maintenance can be performed at an appropriate time, and productivity is improved. The generation of good products can be prevented.
[0010]
In the embodiment shown in the figure, when an alumina thin film having a thickness of 500 mm is formed on 1000 substrates 4, when the total thickness of the thin films on each substrate 4 reaches 50 μm (1000 substrates), ions of the ionometer An ion current of 1 nA was detected from the electrode 12 constituted by the collector. Furthermore, when the alumina thin film was formed on the remaining substrates and the film thickness distribution and film stress of the alumina formed on each substrate 4 were examined, the characteristics of the insulator until the 1 nA ion current was detected were good. However, those manufactured after that had a poor film thickness distribution and a large variation in film stress.
[0011]
【The invention's effect】
As described above, according to the present invention, since an electrode such as an ionization ion collector for monitoring the plasma generation state is provided in the film formation chamber of the sputtering apparatus for producing the insulator, the insulator adheres to the film formation chamber. It is possible to detect an abnormality in the plasma generation state due to the above, and it is possible to improve the productivity by knowing the accurate maintenance time and to produce a product with uniform quality.
[Brief description of the drawings]
FIG. 1 is a cutaway side view of a conventional sputtering apparatus for producing an insulator. FIG. 2 is a cutaway side view showing an embodiment of the present invention. FIG. 3 is an explanatory view of an abnormal state of plasma.
DESCRIPTION OF SYMBOLS 1 Film-forming chamber, 3 Cathode electrode, 4 Substrate, 6 Insulator formation target, 7.8 Gas introduction pipe, 10 Deposition plate, 11 Plasma, 12 electrode,

Claims (2)

In a deposition chamber which is evacuated, the substrate and the cathode electrode and the insulating material forming the target provided, in the apparatus for making insulation sputtered particles from the target are deposited on the substrate, the film forming chamber An adhesion preventing plate for preventing the insulator from scattering is provided in front of the inner wall of the film, and the plasma generation state diffusing into the space between the inner wall of the film forming chamber and the adhesion preventing plate is monitored by the electrode. A sputtering apparatus for producing an insulating material.   The said electrode was comprised with the ionization ion collector, The sputtering apparatus for insulator preparation of Claim 1 characterized by the above-mentioned.

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