JPH0448092A - Reactive dry etching method - Google Patents

Abstract

PURPOSE:To completely remove the packing material and to clean the surface of a recessed shape part by successively treating the packing material in the recessed shape part with reactive gas high in reactivity and reactive gas high in sputtering properties by a parallel plane type reactive dry etching device. CONSTITUTION:A lower magnetic core 2 and an insulated layer 4 are successively formed on a base plate 1. A back contact part 8 is formed by performing reactive dry etching with fluorohydrocarbon-based gas and the lower magnetic ore 2 is exposed. Then the insulated layer 4 and the back contact part 8 are coated with an organic film 5 and, furthermore,, a metallic film 6 is formed. Thereafter, the metallic film 6 on the back contact part 8 is removed. Then oxygen is utilized and the organic film 5 on the back contact part 8 is etched by a parallel plane type reactive dry etching device. Thereafter, the reactive gas is changed over to a gaseous mixture of oxygen and argon from oxygen. Sputtering properties of etching are enhanced and the residual organic film is removed. Thereby a reactive product and decomposition material are made unpresented on the lower magnetic core 2.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a reactive dry etching method using a parallel plate type reactive dry etching apparatus.

[Conventional technology]

As shown in FIG. 2, a wire-wound thin film magnetic head includes a substrate 1, a lower magnetic core 2 made of a ferromagnetic thin film formed to cover the substrate 1, and a multilayer spiral magnetic head on the lower magnetic core 2. It mainly consists of a winding conductor layer 3 formed on the winding conductor layer 3 and a step-shaped upper magnetic core 9 connected to the lower magnetic core 2 and provided at a position corresponding to the spiral center of the winding conductor layer 3. There is. Note that the winding conductor layer 3 is covered with an interlayer insulating layer, which will be described later, to prevent short circuits. In addition, the lower magnetic core 2 is made of, for example, Fe-Al! A ferromagnetic material mainly composed of Fe such as -3i is used.

By the way, with the recent increase in the density of magnetic recording, magnetic recording media with high coercive force are being used, and even in thin film magnetic heads, it is necessary to sufficiently magnetize such magnetic recording media with high coercive force. There is a need for saturation magnetization characteristics that can be achieved. Therefore, in order to improve the saturation magnetization characteristics, the thickness of the upper magnetic core 9 is increased, and the thickness is usually set to 5 to 30 μm.

When forming the upper magnetic core 9 having a relatively thick film thickness by etching, the wet type 1 notching method is used.
Due to the large influence of side etching, it is difficult to maintain the accuracy of the track width.In addition, in the ion milling method, the winding conductor layer 3 may be partially cut due to the film thickness distribution of the upper magnetic core 9 material and the etching rate distribution. It may be etched and cause wire breakage.

Therefore, the following method of forming the upper magnetic core 9 is adopted.

That is, as shown in FIG. 3(a), a lower magnetic core 2 and an insulating layer 4 in which a wire-wound conductor layer 3 as a magnetic field generating coil is inserted are sequentially formed on a substrate 1. After that, an organic film 5 is formed to cover the insulating layer 4. In addition,
For example, polyimide resin is used for the organic film 5.

Next, the organic film 5 is masked with a metal film 6 such as Al or Cu, and the organic film on the winding conductor layer 3 is etched by a reactive dry etching method using oxygen gas, as shown in FIG. Remove membrane 5.

Then, the metal film 6 serving as the mask is removed, and a magnetic layer 10 is formed to cover the insulating layer 4 and the organic film 5, as shown in FIG. And ion milling method,
The magnetic layer 10 is formed by a wet etching method or a grinding method.
is processed to form the upper magnetic core 9 as shown in the same figure (d).
get. Finally, the remaining organic film 5 is removed by a plasma etching method using oxygen gas or a dissolving method using an organic solvent, and the upper part provided on the winding conductor layer 3 is removed as shown in FIG. Magnetic core 9 is completed.

According to the formation method using the organic film 5 as described above, the upper magnetic core 9 can be formed with high accuracy in track width without damaging the winding conductor layer 3 or the insulating layer 4.

[Problem to be solved by the invention]

By the way, the part where the upper magnetic core 9 is connected to the lower magnetic core 2 (see FIG. 2) corresponds to the spiral center of the winding conductor layer 3, and as shown in FIG. A portion of the insulating layer 4 is removed in a concave shape to form a hack contact portion 8 in which the lower magnetic core 2 is exposed. Then, the above-mentioned upper magnetic core 9 is formed thereon.

That is, according to the above structure, after the organic film 5 and the metal film 6 for mask are formed in sequence, reactive tri-etching using oxygen gas is performed to remove the organic film 5 covering the bank contact portion 8. is removed. At this time, since the hack contact portion 8 has a concave shape, in a general-purpose parallel plate type reactive dry etching device, the central portion of the hack contact portion 8 is etched faster than the peripheral portion. For this reason, as shown in the figure, an organic film 5'' tends to remain in the peripheral area. Therefore, over-etching is performed to completely remove this.

However, the lower magnetic core 2 is also etched due to the over-etching, and as a result, reaction products adhere to the lower magnetic core 2, and a degraded layer 7 is formed on the surface of the lower magnetic core 2, as shown in FIG. This has the problem that it may cause problems.

Furthermore, this reaction product and the altered layer 7 are chemically stable and are not only insoluble in water, xylene, acetone, ethyl alcohol, and other organic solvents, but also do not react with acids or alkalis, so they cannot be removed. This is extremely difficult. Therefore, the upper magnetic core 9 (FIG. 2) is formed not on the clean surface of the lower magnetic core 2 but on the reaction product or the altered layer 7, which reduces the performance of the thin-film magnetic head. It has the problem of

(Means for Solving the Problems) In order to solve the above-mentioned problems, the reactive dry etching method of the present invention performs etching by introducing a reactive gas into a parallel plate type reactive dry etching apparatus. In the reactive dry etching method for removing fillers filled in the etching, the etching process includes a first step using a highly reactive reaction gas and a second step using a reaction gas with higher spunter properties than the first step. The method is characterized in that the second step is performed after the first step.

[For production]

According to the above configuration, when removing the filler filled in the concave portion, specifically, for example, an organic substance, the first step uses, for example, oxygen as a highly reactive reaction gas;
a second step using, for example, a mixed gas of oxygen and argon as a reactive gas having higher soot and smoldering properties than the second step;
Since the second step is performed after the first step, etching is performed efficiently in the first step, and in the second step, the organic matter remaining around the concave portion is removed and the organic matter deposited on the surface of the concave portion is removed. Reaction products, altered layers, etc. are removed by sputtering. As a result, not only the organic substances in the concave portions are completely removed, but also a clean surface appears in the concave portions.

[Example] As an example of the present invention, a step of forming a connecting portion between a lower magnetic core and an upper magnetic core, that is, a step of forming a back contact portion in the manufacturing process of a wire-wound thin film magnetic hend will be exemplified. The explanation will be as follows based on FIGS. (a) to (d). Note that members having the same functions as those shown in the drawings of the conventional example are given the same reference numerals.

First, as shown in FIG. 1(a), a lower magnetic core 2 made of a ferromagnetic thin film of an iron-based alloy such as Fe-Al-3i, SiO□ or Si is placed on a substrate 1 made of ferrite or the like.
, N, etc., and a predetermined portion of the insulating layer 4 is etched by reactive dry etching using a fluorocarbon gas until the lower magnetic core 2 is exposed, forming a concave shape. A hack contact portion 8 (concave portion) is formed. Next, an organic film 5 (filling material) is formed of polyimide resin or the like so as to cover the insulating layer 4 and the back contact portion 8 . Then, a metal film 6 for a mask is formed of Cu or the like so as to cover the organic film 5. Then, the metal film 6 on the back contact section 8 is etched by ion milling or the like to form an etching mask pattern for removing the organic film 5 on the back contact section 8.

Next, a parallel plate type reactive dry etching device using oxygen (a highly reactive reactive gas) as a reactive gas was used.
The organic film 5 on the hack contact portion 8 is etched using the metal film 6 as a mask (first step). FIG. 4B shows a stage in the middle of this enching.

As the etching progresses further, the lower magnetic core 2 begins to be exposed at the center of the lower part of the bank contact portion 8, and the lower magnetic core 2 also begins to undergo etching. Then, as shown in FIG. 2C, a reaction product or altered layer 7 begins to form on the lower magnetic core 2.

Note that at this point, the organic film 5' remains around the hack contact portion 8.

In this example, from this stage, the reaction gas is switched from oxygen to a mixed gas of oxygen and argon (a reaction gas with higher sputtering properties than in the first step) to improve the sputtering properties of etching (second step). process). That is, regarding the organic film 5' around the hack contact part 8,
It is mainly removed by etching with ordinary oxygen, and the reaction products or altered layer 7 on the lower magnetic core 2 are mainly removed by sputtering with argon.
As shown in FIG. 4(d), the organic film 5' is completely removed while ensuring that no reaction product or altered layer 7 remains on the lower magnetic core 2.

By the way, in the above mixed gas, the mixing ratio of argon is 2.
0voI! , % or less, the sputtering properties of etching deteriorate and it becomes difficult to remove the reaction product or the altered layer 7. On the other hand, when the argon mixing ratio exceeds 80 voff%, the etching reactivity decreases, and it takes time to etch the organic film 5 in the peripheral area of the bank contact part 8. As a result, the lower magnetic core 2 The damage to the surface becomes greater. Therefore, the appropriate mixing ratio of argon is 20 to 80 vof%.

By the way, the etching conditions in this example are: gas composition 100% 0□, gas pressure 0°08 Tor
Etching was started with a r, xy etching power density of 0.14 W/cm", and then the gas composition was
of%: Switch to 50voffi%, gas pressure 0.
08Torr, etching power density 0.07W/cm
2, etching is performed with improved sputtering properties.

In this example, since the etching rate of the organic film 5 (FIG. 6(b)) was 1000 etching/min under the above-mentioned condition using the 100% 0□ reaction gas, the etching rate on the back contact portion 8 was If the film thickness of the organic film 5 is 20 μm, then 20
The lower magnetic core 2 will begin to be exposed after 0 minutes. Therefore, at this time, the reaction gas is being switched.

As described above, after the organic film 5 is completely removed and a clean surface of the bank contact portion 8 is obtained, a magnetic layer (not shown) is formed and processed into an upper magnetic core. Therefore, the lower magnetic core 2 and the upper magnetic core are well magnetically coupled. Thereby, using the organic film 5, it is possible to manufacture a thin film magnetic head suitable for high-density magnetic recording that maintains a highly accurate track width and has excellent saturation magnetization characteristics.

In the above embodiments, the process of forming the back contact portions 8 of the lower magnetic core 2 and the upper magnetic core in the manufacturing process of a wire-wound thin film magnetic head has been described, but the process is not limited thereto. The reactive dry etching method of the present invention can be similarly applied to any process in which a filler filled in a concave portion is removed using a method.

〔Effect of the invention〕

As described above, the reactive dry etching method of the present invention includes:
When removing the filler filled in the concave portion, specifically, for example, organic matter, the first step uses oxygen as a highly reactive reaction gas, and the second step uses oxygen as a reaction gas with higher spunter properties than in the first step. For example, the second step includes a second step using a mixed gas of oxygen and argon, and the second step is performed after the first step, so that etching is performed efficiently in the first step, and etching is performed around the concave portion in the second step. Remaining organic matter is removed, and reaction products, altered layers, etc. deposited on the surface of the concave portion are removed by sputtering. This results in
Not only is the filler in the concave portion completely removed, but the concave portion has a clean surface.

[Brief explanation of the drawing]

FIGS. 1(a) to 1(d) show an embodiment of the present invention, and are explanatory diagrams showing a process of forming a connecting portion between a lower magnetic core and an upper magnetic core in the manufacturing process of a wire-wound thin film magnetic head. It is. 2 to 4 show conventional examples. FIG. 2 is a perspective view of a wire-wound thin film magnetic hand. FIGS. 3<a> to 3(e) are explanatory diagrams showing the process of forming the upper magnetic core of a wire-wound thin film magnetic head. FIGS. 4(a) and 4(b) are explanatory diagrams showing a process of forming a connecting portion between a lower magnetic core and an upper magnetic core in the manufacturing process of a wire-wound thin film magnetic head. 1 is a substrate, 2 is a lower magnetic core, 3 is a winding conductor layer, 4 is an insulating layer, 5.5゛ is an organic film (filling), 6 is a metal film, 7 is a degraded layer, 8 is a back contact part ( 9 is an upper magnetic core, and 10 is a magnetic layer. Patent applicant Sharp Corporation Figure 1 (a) Figure 1 (b) Figure (C) Figure (d) Figure (a) Figure (b) Figure (C) Figure (d)

Claims (1)

[Claims] 1. In the reactive dry etching method, which performs etching by introducing a reactive gas into a parallel plate type reactive dry etching apparatus to remove the filler filled in the recessed part, the above etching uses a highly reactive reactive gas. A reactive dry etching method comprising a first step and a second step using a reactive gas with higher sputtering properties than the first step, and characterized in that the second step is performed after the first step.