JPS6342349B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a magnetic bubble memory element used in a storage device such as an electronic computing device, and particularly to a method for manufacturing a bubble transfer path thereof.

The storage density of magnetic bubble memories has been increasing due to the recent increase in the amount of information and the demand for smaller devices. Under these circumstances, in order to increase the density of magnetic bubble memory, which uses conventional soft magnetic thin film patterns such as permalloy as bubble transfer paths, to 4M bits or more, micropatterns with a pattern period of 2 to 3 μm are required. However, it is difficult to form fine details of such micropatterns due to the limitations of optical lithography.

[Prior Art] For this reason, a method as shown in FIG. 3 has been developed as a method for producing fine patterns. In this method, first, as shown in figure a, SiO ₂ is placed on top of the bubble crystal 1.
A spacer 2 and a thin film 3 of non-magnetic material are formed, and then a resist mask 4 is formed thereon as shown in figure b, and ion etching is performed to form a pattern 5 of non-magnetic material as shown in figure c. Next, as shown in Figure d, the mask 4 is removed and a soft magnetic thin film 6 is formed over the entire surface. Next, a resist mask 7 is formed thereon as shown in Fig. e, and etching is performed to form a soft magnetic pattern 8 as shown in Fig. F. The soft magnetic pattern 8 thus formed is provided with a steep step a by the pattern 5 of non-magnetic material, and the magnetic discontinuity caused by this step makes it possible to give directionality to the transfer of bubbles. Therefore, according to this method, a bubble transfer pattern smaller than that of the conventional method can be formed even by optical lithography.

[Problem that the invention seeks to solve]

In the above method, it is necessary to form a resist pattern 7 spanning a steep step in the step shown in FIG. There is a problem in that it is difficult to form soft magnetic patterns.

[Means for solving problems]

The present invention provides a method for manufacturing a magnetic bubble transfer path that solves the above problems, and the means thereof include:
A pattern with a two-layer structure of two types of non-magnetic materials is formed on the magnetic bubble material, then a soft magnetic material is laminated to the same thickness as the first layer of the non-magnetic pattern, and then The second layer is etched to remove the second layer of the non-magnetic pattern and the soft magnetic material thereon, and then a resist pattern is created so as to span the first layer of the non-magnetic pattern and the soft magnetic material, and then etched. A method for manufacturing a magnetic bubble transfer path is characterized in that it comprises steps of removing soft magnetic material outside the resist pattern.

[Effect]

In the method for manufacturing the magnetic bubble transfer path, when the second layer of the non-magnetic pattern is etched away, the remaining first layer of non-magnetic material and the soft magnetic material become almost on the same plane and are flattened. Since the photoresist for forming the soft magnetic pattern is formed with a uniform thickness, a good soft magnetic pattern can be formed by patterning and etching the photoresist in the next step.

〔Example〕

Embodiments of the present invention will be described in detail below with reference to the drawings.

FIG. 1 shows a process diagram for explaining one embodiment of the present invention. In the figure, 10 is a bubble material;
11 is a spacer, 12 is a first layer of nonmagnetic material, 1
3 is a second layer of non-magnetic material, 14 is a soft magnetic material, 1
Reference numeral 5 indicates a photoresist, and reference numeral 16 indicates a soft magnetic pattern.

In this embodiment, first, as shown in Fig. a, the bubble material 10
A pattern having a two-layer structure is formed using two types of nonmagnetic materials, a first layer of nonmagnetic material 12 and a second layer of nonmagnetic material 13, with spacers 11 interposed therebetween. Then b
As shown in the figure, a soft magnetic material 14 is laminated on the entire surface to a thickness equal to that of the first layer nonmagnetic pattern 12. Then the second
The non-magnetic material 13 of the layer is selectively etched to remove the second layer of non-magnetic material 13 and the soft magnetic material 14 thereon as shown in FIG. As a result, the nonmagnetic pattern 12 and the soft magnetic material 14 of the first layer become on the same plane and are flattened. Next, a photoresist is applied thereon and patterned to form a photoresist pattern 15 as shown in Figure d. Finally, the soft magnetic material 14 is etched using the photoresist pattern 15 as a mask to remove unnecessary portions and form a soft magnetic pattern 16. FIG. 2 is a plan view of the completed pattern, in which 12 is the first layer of non-magnetic material and 16 is the soft magnetic pattern.

Note that the two types of nonmagnetic materials must be materials that can be selectively etched; for example, if the first layer 12 is
If Ti is used for the second layer 13 of Al--Cu alloy, Al
-Cu is not etched by CFu plasma, so
Ti can be selectively etched.

〔Effect of the invention〕

As explained above, according to the present invention, two types of non-magnetic materials are used to form the details of the soft magnetic pattern, and by selectively etching one of them, the surface before the soft magnetic pattern is formed is flattened. Therefore, it becomes easy to form a resist pattern for the next production of a soft magnetic pattern, and a magnetic bubble transfer path with a good shape can be formed.

[Brief explanation of drawings]

FIG. 1 is a process diagram for explaining the method of manufacturing a magnetic bubble transfer path of the present invention, FIG. 2 is a plan view of a transfer path manufactured by the method of manufacturing a magnetic bubble transfer path of the present invention, and FIG. FIG. 3 is a process diagram for explaining a conventional method for manufacturing a magnetic bubble transfer path. In the figure, 10 is a bubble material, 11 is a spacer, 1
2 is a first layer of non-magnetic material, 13 is a second layer of non-magnetic material, 14 is a soft magnetic material, 15 is photoresist,
16 each indicate a soft magnetic pattern.

Claims (1)

[Claims] 1. A pattern with a two-layer structure of two types of non-magnetic materials is formed on the magnetic bubble material, and then a soft magnetic material is laminated to the same thickness as the first layer of the non-magnetic pattern, and then the non-magnetic pattern After etching the second layer of the non-magnetic pattern to remove the second layer of the non-magnetic pattern and the soft magnetic material thereon, and then creating a resist pattern so as to span the first layer of the non-magnetic pattern and the soft magnetic material. 1. A method for manufacturing a magnetic bubble transfer path, comprising steps of etching to remove soft magnetic material outside the resist pattern.