JP3564313B2 - Method of forming insulating film for thin film magnetic head - Google Patents

Description

【００１４】
高周波電力小とは実験で使用したスパッタ装置で高周波電力を０．５〜１．５ｋＷの範囲に設定してスパッタした場合であり、高周波電力大とは、高周波電力を３．５〜５．０ｋＷの範囲に設定してスパッタした場合である。また、バイアス電圧は５０〜１５０Ｖとした。
【００１５】
図３はスパッタ条件を変えた４種のサンプルと従来方法によって形成したサンプルについて、絶縁膜が破壊される電界強度を測定した結果を示す。測定値は所定の条件でスパッタして形成したアルミナの絶縁膜を金属で挟み、電圧を印加して絶縁膜が絶縁破壊された際の電圧を膜厚で割って得たものである。
【００１６】
なお、図３、４で示した各サンプルのスパッタ条件は以下のとおりである。

【００１７】
図３に示す測定結果は、従来方法によって形成したアルミナの絶縁膜、すなわち１回の成膜工程で形成した絶縁膜にくらべて、上記Ａ＋Ａ、Ａ＋Ｂ、Ｃ＋Ａ、Ｃ＋Ｃの４種のサンプルはいずれも電界強度が向上しており、絶縁膜として優れた絶縁特性を有することが確かめられた。なお、上記の４種のサンプルのうちＡ＋ＡのサンプルとＡ＋Ｂのサンプルが他のサンプルに比較して良好な結果が得られた。
【００１８】
図４は、アルミナの絶縁膜の膜厚を薄くしていった際に絶縁不良が発生する割合を調べた結果を示す。従来方法でアルミナの絶縁膜を形成した場合、膜厚が９５０オングストローム〜８３０オングストローム程度の場合は不良発生率が１０％以下であるが、膜厚が７００オングストローム程度になると不良発生率が８０％以上となる。これに対して、上記の４種類のサンプルについて膜厚を変えて不良発生率を調べたところ、７００オングストローム程度の膜厚であっても不良発生率は１０％以下であった。
この実験結果は、複数回のスパッタ操作を行うことによってアルミナの絶縁膜の絶縁特性が明確に改善できたことを示している。
【００１９】
本発明方法によれば、絶縁膜の膜厚を薄くしてなおかつ絶縁特性を向上させることが可能であるから、薄膜磁気ヘッドのギャップ間隔をより狭く形成することが可能となり、磁気ディスクの高密度化に好適に対応することが可能になる。また、薄膜磁気ヘッドの信頼性を向上させることができ、製造歩留まりの向上にも有効に寄与することができる。
また、本発明に係る絶縁膜の形成方法は従来の薄膜磁気ヘッドの製造方法及び製造装置がそのまま使用できるという利点もある。
【００２０】
【発明の効果】
本発明に係る薄膜磁気ヘッドの絶縁膜の形成方法によれば、膜厚を薄く形成してなおかつ絶縁特性の優れた絶縁膜を得ることができるから、薄膜磁気ヘッドの製造に好適に適用でき、信頼性の高い磁気ヘッドを製造し得るとともに、磁気ヘッドの小型化、高密度化にも好適に適用することが可能となる。
【図面の簡単な説明】
【図１】薄膜磁気ヘッドの概略構成を示す断面図である。
【図２】薄膜磁気ヘッドの絶縁膜を形成する工程を示すフロー図である。
【図３】本発明方法によって形成した絶縁膜と従来方法によって形成した絶縁膜の絶縁破壊時の電界強度を測定した結果を示すグラフである。
【図４】本発明方法によって形成した絶縁膜と従来方法によって形成した絶縁膜について、膜厚を変えたときの不良発生率を調べた結果を示すグラフである。
【符号の説明】
１０ 再生ヘッド
１０ａ 磁気抵抗効果素子
１０ｂ 端子
１２ 基板
１４ 下部シールド層
１６、１８ 絶縁膜
２０ 上部シールド層
４６ はんだめっき被膜
５０ はんだボール[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a method for forming an insulating film of a thin-film magnetic head.
[0002]
[Prior art]
A magnetic head used in a magnetic disk device has a reproducing head for reproducing signals from the magnetic disk and a recording head for writing signals to the magnetic disk. FIG. 1 shows a schematic configuration of a reproducing head portion of a magnetic head, and shows a magnetoresistive element 10a and a terminal 10b constituting a reproducing head 10. Reference numeral 12 denotes a substrate, on which a lower shield layer 14 is provided as a magnetic shield layer, a magnetoresistive element 10a and a terminal 10b are provided via an insulating film 16, and an upper shield layer 20 is provided via an insulating layer 18. Is provided.
[0003]
The lower shield layer 14 and the upper shield layer 20 are provided for magnetically shielding the reproducing head 10. Since these shield layers are conductors, the magnetoresistive effect elements 10a and The terminal 10b is electrically insulated from the shield layer.
The shield layer, the insulating films 16 and 18 and the reproducing head 10 are formed on the substrate 12 by sputtering. That is, a target is placed in a vacuum chamber, a sputtering gas such as an argon gas is introduced, high-frequency power is applied to a cathode, and a film is formed on a substrate.
[0004]
[Problems to be solved by the invention]
By the way, in recent years, as the density of magnetic disk devices has increased, the size of magnetic heads has been further reduced, and it has been demanded that the insulating films 16 and 18 formed on the thin film magnetic head be formed thinner. In a conventional thin-film magnetic head, the insulating film is formed to have a thickness of about 1000 to 1500 angstroms. However, it is required that this thickness be about several hundred angstroms. However, when the film thickness is reduced, the insulating characteristics of the insulating film such as a decrease in the withstand voltage due to a pinhole or the like become a problem.
[0005]
The present invention relates to a method for forming an insulating film in such a thin-film magnetic head, wherein an insulating film having a required thickness and a smaller thickness than an insulating film used in a conventional thin-film magnetic head. An object of the present invention is to provide a method for forming an insulating film of a thin-film magnetic head which can be formed, thereby obtaining a small-sized thin-film magnetic head having high reliability.
[0006]
[Means for Solving the Problems]
The present invention has the following configuration to achieve the above object.
That is, in a method for forming an insulating film of a thin-film magnetic head in which an insulating film for electrically insulating a conductive layer formed on a substrate and another formed layer is formed, the insulating film is formed in a vacuum chamber. in the time of film formation by sputtering, divided sputtering operation a plurality of times of sputtering operation, as the hold operation to stop discharging when moving to next sputter operations from each round of the sputtering operation, to flow the sputtering gas in a vacuum chamber It is characterized in that a required film thickness is obtained by performing an operation for elapse of time for cooling the substrate .
Further, in the method for forming an insulating film of a thin-film magnetic head in which an insulating film for electrically insulating a conductor layer formed on a substrate and another formed layer is formed, the insulating film is formed in a vacuum chamber. When forming a film by sputtering, the sputtering operation is divided into a plurality of sputtering operations, and as a hold operation to stop discharge when shifting from each sputtering operation to the next sputtering operation, the insulating film is sputtered, and then a vacuum chamber is formed. It is characterized by performing an operation of elapse of time for cooling the substrate without evacuating the vacuum and breaking the vacuum, and introducing a sputtering gas again at the next sputtering operation to obtain a required film thickness. .
The sputtering operation for obtaining the required film thickness is divided into a plurality of sputtering operations, and the holding operation is performed in the middle of each sputtering operation to cool the substrate, thereby suppressing the growth of pinholes in the insulating film, and contract the hole it is possible to improve the insulation properties of the insulating film.
Also, each time the sputtering operation, it is effective to carry out by adjusting the magnitude of the high-frequency power applied to the target each time, also, each time the sputtering operation, the direction of the bias voltage to deposit an insulating film on the substrate side Is also effective in improving the insulating properties of the insulating film.
[0007]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawings.
The method of forming the insulating film of the thin-film magnetic head according to the present invention is a method of forming insulating films 16 and 18 for electrically insulating the shield layer of the thin-film magnetic head shown in FIG. 1 from the magnetoresistive element 10a and the terminal 10b. It is preferably applied to In the embodiment, an insulating film is formed by using alumina as an insulator to form an alumina film by a sputtering method.
[0008]
As a method for forming an insulating film, the present invention is characterized in that an insulating film having a required thickness is obtained by performing a plurality of sputtering operations. That is, when forming an alumina film to a thickness of, for example, 600 angstroms, the film is formed by sputtering twice in 300 angstroms. The reason why the sputtering operation is performed a plurality of times is to perform a hold operation for stopping the discharge and cooling the substrate once for each sputtering operation.
[0009]
The hold operation is intended to suppress the growth of pinholes in the film formation layer by cooling the substrate after performing the sputtering operation, and to shrink the pinholes. Therefore, in the hold operation, after the sputtering operation is performed, the time for temporarily stopping the discharge and cooling the substrate is allowed to elapse. As a hold operation, a method in which a sputtering gas such as an argon gas is caused to flow into a vacuum chamber at a constant gas pressure, or a method in which after sputtering, the vacuum chamber is once evacuated to a vacuum, and the sputtering is performed again in the next sputtering operation There is a method of introducing gas. In any case, the surface of the film formation layer must be kept clean so as not to break the vacuum of the vacuum chamber.
[0010]
In each sputtering operation, high-frequency power is applied to the target, but the high-frequency power may be the same each time, or the film-forming conditions may be adjusted by increasing or decreasing the high-frequency power each time. By changing the high-frequency power and adjusting the film formation conditions, it is possible to further improve the insulating characteristics of the insulating film.
In addition, during each sputtering operation, the insulating characteristics of the insulating film can be improved by adjusting the film forming conditions by applying a bias voltage so as to draw alumina (insulator) into the substrate.
[0011]
FIG. 2 is a flowchart showing a method for forming an insulating film according to the present invention. As shown in the figure, a sputtering operation and a holding operation are repeatedly performed to obtain an insulating film having a required film thickness. The number of times of the sputtering operation is not particularly limited, and the film thickness formed in each sputtering operation does not need to be the same. Further, power adjustment and bias adjustment in the sputtering operation can be appropriately set, and the hold method in the hold operation can also be appropriately set.
[0012]
3 and 4 show measurement results of comparing the insulating properties of an alumina insulating film formed by the above method and an alumina insulating film formed by the conventional method. All the samples according to the above method were obtained by sputtering alumina twice in the same thickness, and the sputtering conditions were as follows.
[0013]
[Table 1]

[0014]
The high frequency power is low when high frequency power is set in the range of 0.5 to 1.5 kW by the sputtering apparatus used in the experiment, and the high frequency power is high when the high frequency power is 3.5 to 5.0 kW. This is the case where the sputtering is performed in the range shown in FIG. The bias voltage was set to 50 to 150V.
[0015]
FIG. 3 shows the results of measuring the electric field strength at which the insulating film is destroyed for the four kinds of samples under different sputtering conditions and the samples formed by the conventional method. The measured value is obtained by sandwiching an alumina insulating film formed by sputtering under predetermined conditions with a metal, applying a voltage, and dividing a voltage when the insulating film is broken down by a film thickness.
[0016]
The sputtering conditions for each sample shown in FIGS. 3 and 4 are as follows.

[0017]
The measurement results shown in FIG. 3 indicate that the four types of samples A + A, A + B, C + A, and C + C are all different from the alumina insulating film formed by the conventional method, that is, the insulating film formed in one film forming step. It was confirmed that the electric field strength was improved and the insulating film had excellent insulating properties. The A + A sample and the A + B sample among the above four samples showed better results than the other samples.
[0018]
FIG. 4 shows the result of examining the rate at which insulation failure occurs when the thickness of the alumina insulating film is reduced. When an alumina insulating film is formed by a conventional method, the defect occurrence rate is 10% or less when the film thickness is about 950 angstroms to 830 angstroms, but when the film thickness is about 700 angstroms, the defect occurrence rate is 80% or more. It becomes. On the other hand, when the defect occurrence rate was examined by changing the film thickness of the above four types of samples, the defect occurrence rate was 10% or less even at a film thickness of about 700 Å.
The experimental results show that the insulating properties of the alumina insulating film could be clearly improved by performing the sputtering operation a plurality of times.
[0019]
According to the method of the present invention, it is possible to reduce the thickness of the insulating film and to improve the insulating characteristics. It is possible to suitably cope with the development. Further, the reliability of the thin-film magnetic head can be improved, and it can also effectively contribute to the improvement of the production yield.
Further, the method for forming an insulating film according to the present invention has an advantage that a conventional method and apparatus for manufacturing a thin-film magnetic head can be used as it is.
[0020]
【The invention's effect】
According to the method for forming an insulating film of a thin-film magnetic head according to the present invention, it is possible to obtain an insulating film having a small thickness and excellent insulating properties, and thus can be suitably applied to the manufacture of a thin-film magnetic head. A highly reliable magnetic head can be manufactured, and the magnetic head can be suitably applied to miniaturization and high density of the magnetic head.
[Brief description of the drawings]
FIG. 1 is a sectional view showing a schematic configuration of a thin-film magnetic head.
FIG. 2 is a flowchart showing a step of forming an insulating film of the thin-film magnetic head.
FIG. 3 is a graph showing the results of measuring the electric field strength at the time of dielectric breakdown of the insulating film formed by the method of the present invention and the insulating film formed by the conventional method.
FIG. 4 is a graph showing the results of examining the defect occurrence rate when the film thickness is changed for the insulating film formed by the method of the present invention and the insulating film formed by the conventional method.
[Explanation of symbols]
Reference Signs List 10 reproducing head 10a magnetoresistive element 10b terminal 12 substrate 14 lower shield layers 16, 18 insulating film 20 upper shield layer 46 solder plating film 50 solder ball

Claims (4)

A method for forming an insulating film of a thin-film magnetic head, wherein an insulating film for electrically insulating a conductor layer formed on a substrate and another film-forming layer is formed.
It said insulating film when forming by sputtering in a vacuum chamber, as a hold operation to stop discharging the sputtering operation a plurality of times of sputtering operation, when moving to next sputter operations from each round of sputtering operation, the vacuum chamber A method for forming an insulating film of a thin-film magnetic head, characterized in that a required thickness is obtained by performing an operation for allowing a time for cooling a substrate by flowing a sputtering gas therein . In a method of forming an insulating film of a thin-film magnetic head, the insulating film is formed by electrically insulating a conductive layer formed on a substrate and another formed layer.
When the insulating film is formed by sputtering in a vacuum chamber, the sputtering operation is divided into a plurality of sputtering operations, and the insulating film is used as a hold operation for stopping discharge when shifting from each sputtering operation to the next sputtering operation. After the sputtering, the vacuum chamber is evacuated, and the operation for allowing the time for cooling the substrate to elapse without breaking the vacuum is performed. method for forming the insulating film of the thin film magnetic head you and obtaining a. 3. The method for forming an insulating film of a thin-film magnetic head according to claim 1 , wherein each sputtering operation is performed by adjusting the magnitude of the high-frequency power applied to the target each time . The sputtering operation for each round, forming method according to claim 1, 2 or 3 thin film magnetic head of the insulating film, wherein the performing by applying a bias voltage direction of depositing an insulating film on the substrate side.

Images