JPS62285294A - Manufacture of magnetic bubble memory element - Google Patents

Abstract

PURPOSE:To eliminate the need for an etching mask pattern for bubble crystals corresponding to a 'Permalloy(R)' transfer line without deteriorating a bias margin substantially by thinning the film thickness of the bubble crystal of the ion implantation transfer line part by etching. CONSTITUTION:An ion implantation layer 29 is formed on magnetic bubble crystals 11, a 'Permalloy(R)' pattern is formed thereon via an insulation layer to manufacture a magnetic bubble memory element. In such case, the ion implantation layer is removed by a prescribed depth by etching before the forming of the 'Permalloy(R)' pattern. In the relation between the etching depth of the ion implantation layer and the collapse magnetic field, as the etching depth is increased, the collapse magnetic field is increased. Thus, when the etching depth of the ion implantation layer is properly selected, the bias magnetic field level of the ion implantation layer is made coincident with that of the 'Permalloy(R)' transfer line.

Description

[Detailed Description of the Invention] 3. Detailed Description of the Invention [Summary] In an ion-implanted bubble element or a hybrid bubble memory element having an ion-implanted transfer path and a permalloy transfer path, a bubble crystal in the ion-implanted transfer path portion By reducing the film thickness by etching, the bias magnetic field margin between the ion-implanted transfer path and the permalloy transfer path, that is, the collapse magnetic field, is completely eliminated, and the poetic characteristics are stabilized and improved.

[Industrial application field]

The present invention relates to a magnetic bubble memory element used in a storage device such as an electronic computing device, and more specifically,
The present invention relates to its manufacturing method.

[Conventional technology]

For example, in a hybrid bubble device, the operating margin (collapse magnetic field) of both the ion-implanted transfer path and the permalloy transfer path must be the same bias, but the ion-implanted transfer path usually has a lower level (this is It needs to be at the same level as the permalloy transfer path.

Conventionally, this method has been to match the collapse magnetic field of the permalloy transfer path to that of the ion kain transfer path, so to speak, to match the ``high'' side to the ``low'' side.

The relationship between the etching depth of the bubble crystal portion of the permalloy transfer path region and the collapse magnetic field is as shown by the broken line in Figure 3. It is known that the larger the etching depth, the smaller the collapse magnetic field, that is, the smaller the bias margin. There is.

Based on this fact, conventionally the etching depth of the bubble crystal portion of the Permalloy transfer path region was increased until the bias margin of the Permalloy transfer path matched the bias margin of the ion implantation transfer path. , conventionally, as shown in FIGS. 4(1) to (5), the substrate 10
A mask pattern 21 for etching a portion 23 of the bubble crystal 11 corresponding to the permalloy pattern is formed on the bubble crystal 11 formed above, and then the bubble crystal 1 is etched.
1 was etched by ion silling, the mask pattern 21 was removed, an ion implantation mask 25 was formed, a transfer path pattern 27 was etched, and finally ions were implanted there to form an ion implantation layer 29. . Permalloy pattern 33 is spacer (insulating layer) 31
is formed on the crystal portion 23 via the . In this method, since the crystal part 23 corresponding to the permalloy pattern is etched by a depth h, the collapse magnetic field is lowered based on the phenomenon shown in FIG. 3, and the bias margin matches the bias magnetic field of the ion-implanted layer, which is lower than that. do. In other words, the etching depth h is selected so that the bias margin of the permalloy transfer path and the bias margin of the ion implantation layer are approximately the same.

[Problem that the invention seeks to solve]

However, in the above conventional method, the bias margin of the permalloy transfer path is matched to that of the ion-implanted layer, which not only causes the problem that the bias margin becomes small, but also requires that the bubble crystal portion 23 corresponding to the permalloy transfer path be etched. Mask pattern 2 to perform
1, the manufacturing method is troublesome and expensive.

The present invention was created in view of these points, and is a simple etching method that does not substantially reduce the bias margin and eliminates the need for an etching mask pattern for the bubble crystal portion corresponding to the permalloy transfer path. The purpose of this invention is to provide a method for manufacturing an inexpensive magnetic bubble memory element.

[Means for solving problems]

Therefore, in the present invention, when producing a magnetic bubble memory element by forming an ion-implanted layer on a magnetic bubble crystal and then forming a permalloy pattern thereon via an insulating layer, it is necessary to It is characterized in that the ion implantation layer is removed by etching to a predetermined depth.

[For production]

The inventor investigated the relationship between the etching depth of the ion-implanted layer and the collapse magnetic field, and as a result, as shown by the solid line in FIG. I found out that it does. (Ion implantation conditions are 200KeV, 2XIO”N
e'/c+J, 60KeV, 2XIO”
H2”/ai, 50KeV, 7 X 10”N
e'/cj) However, if the etching depth of the ion-implanted layer is appropriately selected, the bias magnetic field level of the ion-implanted layer can be made to match that of the permalloy transfer path.

According to the present invention, the bias margin of the ion implanted layer matches the bias margin of the permalloy transfer path by increasing the etching depth of the ion implanted layer, thereby achieving the objective.

〔Example〕

FIG. 1 is a diagram showing an embodiment of the present invention, and shows (1) to (5)
) is a diagram explaining the process. In this embodiment, first, as shown in FIG. 1(1), a mask 35 (the mask 25 in FIG. equivalent) is formed. After forming an ion implantation transfer pattern 27 using this mask 35, ions are implanted thereto to form an ion implantation layer (pattern) 29 (FIG. 1(2)). Next, the ion-implanted layer 29 is etched to a predetermined depth D by ion milling using the mask 35 (FIG. 1(3)). As a result, by designing the etching depth D of the ion-implanted layer to an appropriate value, as shown in FIG. The greatest feature of the present invention is that the ion implantation transfer path once formed in this way is removed by etching to a predetermined depth.

The subsequent steps are the same as those in Figure 4 (4) and (5),
After removing the mask 35 (FIG. 1 (4)), the spacer 3
1 to form a permalloy transfer path pattern 33 (
Figure 1 (5)).

Fig. 2 shows another embodiment of the present invention, and Fig. 2 (1)
The steps up to (2) are shown in Figure 1 (1).

Same as (2), but before etching the ion implantation layer 29 by ion milling, the ion implantation mask 35 is etched.
is removed and the entire surface is etched to a depth D by ion milling (FIG. 2(3)). That is, in this embodiment, as is clear from FIG. 2(4), the bubble crystal 11 corresponding to the permalloy transfer path is also etched by a depth D, so the collapse magnetic field in this area becomes small, as is clear from FIG. 3. . In other words, in the embodiment shown in FIG. 2, the bias margin of the ion implantation layer and the bias margin of the permalloy transfer path are brought close to each other and matched at some point in the middle. The etching depth of the ion-implanted layer can be reduced compared to the case of FIG. 1, which depends only on the reduction in film thickness. Also, the second
The illustrated embodiment also has the secondary effect that no step is formed on the surface of the bubble crystal. The process shown in Figure 2 (4) and the following steps are shown in Figure 1 (
This is the same as 5).

In the embodiment shown in FIG. 2, the bubble crystal 11 and the ion-implanted layer 29 are etched in consideration of the etching depth D.
Although it is possible to design the layer to be thin, as in the present invention, it is preferable to once form the ion-implanted layer to a predetermined thickness and then reduce the film thickness by etching, as the distribution of the implanted ions becomes more uniform. has been confirmed.

〔Effect of the invention〕

As described above, according to the present invention, it is possible to make the bias margins of the ion implantation transfer path and the permalloy transfer path the same level using an extremely simple method, which is extremely useful in practice. .

[Brief explanation of drawings]

Fig. 1 is a diagram for explaining an embodiment of the present invention in the order of steps, Fig. 2 is a diagram showing another embodiment of the present invention, and Fig. 3 is a diagram showing the collapse magnetic field and etching depth of the permalloy transfer path and ion implantation layer. FIG. 4 is a diagram showing the manufacturing process of a conventional magnetic bubble memory element. 11... Bubble crystal 1, 29... Ion implantation layer, 3
3... Permalloy transfer path.

Claims (1)

[Claims] 1. When producing a magnetic bubble memory element by forming an ion-implanted layer on a magnetic bubble crystal and then forming a permalloy pattern thereon via an insulating layer, the ion-implanted layer is etched prior to forming the pattern. A method for manufacturing a magnetic bubble memory device characterized by removing only a predetermined depth.