JPS6048832B2 - magnetic bubble element - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a magnetic bubble element, and in particular to its pattern configuration.

In magnetic bubble elements, permalloy patterns are required for the transfer of magnetic bubbles (hereinafter referred to as "bubbles") and detection by magnetoresistive effect, and bubble generators, dividers, extinguishers, gates, etc. A conductor pattern necessary for control is required, but since the permalloy pattern and the conductor pattern are generally patterned using separate masks, mask alignment is required twice.

This results in poor workability and low product yield.
Therefore, attempts have been made to create these patterns by first mask alignment, as shown in FIGS. 1 and 2.

Fig. 1 shows what is called the mask transfer method. First, as shown in Fig. 1, a magnetic thin film 3 made of permalloy (NiFe) etc. is deposited on a bubble material 1 via a spacer layer 2 made of SiO2 etc. A resist pattern 4 is formed by applying photoresist and exposing and developing it. As shown in the next figure, after a mask material 5 such as titanium (Ti) is deposited, the photoresist 4 is removed using a solvent, and unnecessary portions of the mask material 5 are removed by lift-off. Using the metal mask 5' thus formed, unnecessary parts of the permalloy layer 3 are etched to obtain a permalloy pattern 3' which is a factor. However, in such a pattern of magnetic material, when the magnetic material pattern 3' is used as a bubble detector by utilizing the magnetoresistive effect, the masking metal 5' short-circuits the magnetic material pattern 3' and the detection function is interrupted. Therefore, the metal mask 5' must be removed. Furthermore, when the magnetic material pattern 3' is used as a conductor in a gate portion or the like, it is not satisfactory because of its large specific resistance. Note that 8 is a substrate made of bubble material. On the other hand, if a metal pattern with a low resistivity is also laminated at the same time using the single mask pattern forming method shown in FIG. 2, the pattern can sufficiently function as a conductor.

In other words, as shown in Figure A, by carefully aligning the
After forming a metal layer 6 with low resistivity only in the position where the conductor is to be provided, a permalloy layer 7 is applied over the entire surface as shown in the figure, and this is patterned with a single mask to form a layer as shown in figure C. Get the pattern. In this case, by using the metal pattern 6' side with low resistivity as a conductor and the permalloy pattern 7'' side as a detector based on the magnetoresistive effect, the drawbacks of the case shown in Fig. 1 can be overcome. In order to selectively deposit the metal layer 6 on the metal layer 6, some mask alignment is required, although it may be rough, so in the strict sense it cannot be called a single mask pattern forming method, and the masking process increases accordingly. The present invention provides a magnetic bubble element that can solve the conventional problems such as those shown in FIGS. 1 and 2 all at once.

In order to solve this technical problem, the technical means of the present invention is such that a conductor layer and a magnetic thin film layer, which are provided on a magnetic bubble material with an insulating layer in between, are formed into the same shape by a single mask method or the like. In addition to having a patterned layer structure,
Terminals can be connected to any layer. That is, the patterned surface of the conductive layer and the patterned surface of the magnetic thin film are both exposed at the terminal portion and serve as terminal connection surfaces so that the conductive layer and the magnetic thin film can be selectively or both terminally connected. Next, examples will be used to explain how the magnetic bubble element according to the present invention is actually implemented. FIG. 3 is a sectional view showing a method of manufacturing a magnetic bubble element according to the present invention, and FIG. 4 is an enlarged plan view of a terminal portion of the magnetic bubble element according to the present invention. In the case of the present invention. First, as shown in FIG. 3A, Al-Cu
A metal layer 9 with low resistivity, such as a second insulating layer 10
, a layer 11 of a magnetic film such as permalloy, and a third insulating layer 12 are deposited in this order by vapor deposition, sputtering, etc.
Plain? The entire child has the same layer structure. A mask pattern 13 is then formed on the third insulating layer 12. This may be a metal mask in which a metal such as Ti or Cr is patterned using a lift-off method as shown in FIG.
Even a photoresist mask makes no difference. After forming the mask pattern 13, the conductor layer 9 is patterned all at once by chemical etching or dry etching to obtain the structure of the opening. In this way, since the lowermost conductor layer 9 is etched in one patterning, the insulating layers 10, 12
The thickness should be such that it does not interfere with such etching. The material of the insulating layer is SiO. However, SiO or the like is preferable. When the multilayer pattern formed in this way is used as a conductor, the conductor pattern 9 with low resistivity is used to conduct electricity, and if necessary, the magnetic film pattern 11 and the metal mask pattern 13 are also connected in parallel to conduct electricity. You may. When used as a detector or transfer path, only the intermediate magnetic film pattern 11 is used. In the figure, the multilayer pattern on the left side is used as a conductor, and the magnetic film pattern 11' on the right side is used as a detector or transfer path pattern. In order to be able to freely select and use patterns with the same layer structure depending on the application, the present invention further performs the following terminal processing. FIG. 4 is a plan view of the device in which only the terminal portion is shown enlarged for convenience, and a magnetic bubble memory is formed in the area indicated by the broken line 14 using the single mask method of FIG.
has been completed. 9t and 11t are terminal portions connected to conductor patterns 9 and 11 such as gates in the memory section 14, respectively. Considering the case where the magnetic film pattern 11 is also used as a conductor, the magnetic film pattern 11 is also a terminal portion. 1
It is exposed like 1t.

This terminal is brought out by rough mask alignment and etching, and a part of the terminal is removed by etching down to the second insulating layer 10, exposing the bottom layer conductor pattern like 9t.
The other part is removed by etching up to the third insulating layer 12 to expose the magnetic film pattern as shown in 11t. When only the conductor pattern 9 is energized, its terminal 9t is connected to the mounting plane by wire bonding, and when the magnetic film pattern is also energized, its terminal 11t is also wire-bonded. When the metal mask pattern 13 is also used as a conductor, it can be used as a terminal as it is because it is on the top layer, and there is no need to expose the terminal by etching. 11't is a connection terminal portion of the magnetic film pattern 11' of the detector in the memory section 14.

When using the magnetic film pattern as a detector, it is sufficient to expose only the magnetic film pattern 11' as a terminal. Only the terminal 11't is formed to be exposed and used as a wire bonding terminal. As described above, according to the present invention, a magnetic bubble has a layered structure in which a conductive layer and a magnetic thin film layer, which are provided on a magnetic bubble material with an insulating layer in between, are patterned into the same shape by a single mask method or the like. In the element, both the patterned surface of the conductor layer and the patterned surface of the magnetic thin film are exposed at the terminal portion and serve as a terminal connection surface.

Therefore, by terminally connecting the conductive layer and the magnetic thin film selectively or both together, each pattern can be used independently or in combination as necessary, and the problems of the conventional method can be eliminated. That is, in a conductor portion such as a gate, the current capacity can be arbitrarily selected by using the metal pattern 9 having a low resistivity as a conductor independently or in combination with the magnetic film pattern 11 or the metal mask pattern 13. In addition, since an insulating spacer is interposed between each pattern, in order to insulate the magnetic film pattern from the conductor pattern and maintain detection characteristics, the mask alignment process is increased, although it is only rough as shown in Figure 2. Not only is it unnecessary, and there is no need to take the trouble to remove the metal mask as shown in FIG. 1, it can also be actively used as a conductor.

[BRIEF DESCRIPTION OF THE DRAWINGS] Fig. 1 is a diagram sequentially showing the patterning process of a magnetic bubble element by the conventional mask transfer method, Fig. 2 is a diagram showing the patterning process of the magnetic bubble element by the conventional single mask pattern method, FIG. 3 is a cross-sectional view showing the structure and manufacturing method of the magnetic bubble element according to the present invention, and FIG. 4 is a plan view showing the lead-out terminal portion of the magnetic bubble element according to the present invention. In the figure, 1 is a bubble material, 2, 10, 127 are insulating spacer layers, 9 is a conductor pattern, 11, 11' are magnetic film patterns, 13 is a metal mask, 9t, 11t, 11't
1 is a lead terminal, and 14 is a memory section.

Claims (1)

[Claims] 1. In a magnetic bubble element in which a conductor layer and a magnetic thin film layer provided with an insulating layer sandwiched between them are patterned in the same shape on a magnetic bubble material, the conductor layer and the magnetic thin film are selectively or both connected to terminals. A magnetic bubble element characterized in that the patterned surface of the conductor layer and the patterned surface of the magnetic thin film are both exposed at the terminal portion, and have a portion serving as a terminal connection surface.