JPS599111B2 - Manufacturing method of planar magnetic bubble element overlay - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for manufacturing a planar magnetic bubble element overlay, which is intended to simplify the process and improve reliability.

The mainstream overlay structure of magnetic bubble elements is the so-called conductor-first type, in which a conductor is placed below a driving permalloy element via an insulating layer to provide a gate function.

In this case, the thickness of the permalloy film above the gate function portion becomes thinner at this stepped portion, resulting in so-called step coverage defects, resulting in wire breakage and poor magnetic properties. Also, even if
Even if the step coverage was good, there were many problems, such as the need to consider the magnetic characteristics of the step portion in pattern design. In order to solve these problems,
Several planarization processes have been devised, but all of them are extremely complex and impractical, or require the use of an insulating layer on top of the organic resist used to form the conductor pattern. Various problems arose due to the resist lift-off method.

In other words, in the resist lift-off method, the insulating layer is formed in particular at 5102 to prevent carbonization of the organic resist.
This is done by low-temperature sputtering or low-temperature deposition of SiO. However, in low-temperature SiO2 sputtering, SiO2 clings to the side surfaces of the resist, making resist lift-off difficult, and in low-temperature evaporation of Si0, there are concerns about adhesion.

Furthermore, there was a drawback that a step of forming an insulating layer again was required after lift-off of the organic resist. This invention was made to eliminate the above-mentioned drawbacks of the conventional method, and adopts a lift-off method using a conductive metal instead of a lift-off method using an organic resist, thereby reducing the number of steps and improving reliability. It is an object of the present invention to provide a method for manufacturing a planar magnetic valve element overlay that can be manufactured with high efficiency.

Embodiments of the method for manufacturing a planar magnetic bubble element overlay according to the present invention will be described below with reference to the drawings. 1st
The drawings and FIG. 1 are diagrams showing a manufacturing process for flattening a planar type magnetic valve element for explaining one embodiment thereof. First, as shown in FIG. 1, SiO22 is formed to a thickness of about 1.4 .mu.m on a cleaned wafer 1 by sputtering. This film thickness of SiO22 is the final distance between the Permalloy transfer pattern and the surface of the wafer 1. Next, using the organic resist as a mask, as shown in FIG.
Etsu thousand and CF4+H2 gas pressure 3X10-2t0r
Etch to a depth of 0.8 μm at a power density of 0.3 W/Clll).

At this time, the SiO etching cross section becomes almost perpendicular to the surface of the wafer 1.

Next, the process moves to the step shown in FIG. 3, where the organic resist is peeled off, and then Al--Cu3 is vacuum-deposited as a conductor metal to a thickness of about 0.4 .mu.m over the entire surface of the SiO22.

The substrate heating temperature during this vapor deposition is about 150°C. Furthermore, as shown in Fig. 4, SiO4 was replaced with Al-Cu.
A thickness of 0.5 μm is deposited on the entire surface of No. 3 in the same vacuum (also at this time, the substrate heating temperature during deposition is about 150° C.).

Next, the Al--Cu3 other than the conductor pattern arrangement area 2a is spray-etched at a ratio of hydrochloric acid to water of 1:1, and at the same time, the SiO4 film deposited on the top is removed as shown in FIG.

Through the above steps, A2-0u3 in the conductor pattern arrangement portion 2a is insulated by SiO4.

Moreover, the surfaces of SiO4 and SiO22 are flat with almost no difference in level. Thereafter, a permalloy film 5 is formed by a 0.4μ sputtering method, as shown in FIG. Further, it is patterned by photo-etching technology, and then, as a protective film, a film of SiO26 with a thickness of 0.5 .mu.m is formed on the entire surface by sputtering as shown in FIG.

As described in detail above, according to the method for manufacturing a planar magnetic bubble element overlay of the present invention, SiO is formed as a protective film on a wafer, and this SiO2 is used as a reactive layer using an organic resist on the upper surface as a mask. After etching to a predetermined depth using sputter etching to form a conductor pattern placement area, a conductor metal is vapor deposited on the entire surface of the SiO2, and after SiO is vapor deposited on the entire surface of the conductor metal, conductors other than the conductor pattern placement area are formed. metal and S formed on top of it
After selectively removing iO, the top surfaces of the remaining SiO and SiO2 are flattened without any steps, and the SiO and SiO2 are flattened.
Since the permalloy pattern is formed on O, the insulating layer is already formed on the conductive metal at the end of lift-off, and the step of forming an insulating layer after lift-off can be omitted.

Accordingly, even when compared to the non-planarization process which requires the least number of steps, the number of steps for removing the conductor metal is increased, and there is no need to form an insulating layer on the conductor metal at a particularly low temperature.

In addition, the method of the present invention involves first forming a conductor pattern placement portion (groove) in the protective film and embedding the conductor in the groove, which greatly simplifies the process compared to other planarization techniques. . Furthermore, the method of the present invention allows the overlay structure of a magnetic bubble device to be manufactured using highly reliable materials used in conventional magnetic bubble device formation and IC manufacturing. In addition, since the conductive metal and insulating layers can be formed in the same vacuum, it is possible to form a film with excellent adhesion between the metal and insulating layers, and to create highly reliable circuit patterns that can shorten work time. It has excellent effects such as being able to form.

[Brief explanation of drawings]

1 to 7 are process diagrams for explaining one embodiment of the method for manufacturing a planar magnetic bubble element overlay according to the present invention. 1... Wafer 2... SiO2, 2a
......Conductor pattern arrangement section, 3...Al
-Cul4...SiO, 6...SiO
,,5...Permalloy film.

Claims (1)

[Claims] 1 A protective film of SiO_2 is formed on the wafer, and this protective film is etched to a predetermined depth by reactive sputter etching using the organic resist on the upper surface as a mask to form a conductor pattern arrangement area, and then the surface of the protective film is etched to a predetermined depth. After depositing a conductive metal over the entire surface and providing SiO on the entire surface of the conductive metal, the conductive metal other than the conductor pattern arrangement area and the SiO formed on the top thereof are selectively removed, and the remaining SiO The upper surface of the protective film is planarized, and this Si
A method for manufacturing a planar magnetic bubble element overlay, comprising forming a permalloy pattern on an O and a protective film.