JPS592349A - Formation of oxide superconductor circuit - Google Patents

Abstract

PURPOSE:To enable the pattern formation of the accuracy to several mum without changing characteristics by a method wherein a pattern of organic photo resist is formed on a substrate or a patterned substrate, next an oxide thin film is vapor-deposited, thereafter the organic photo resist is removed by combustion and evaporation, and thus the pattern of the oxide thin film is formed. CONSTITUTION:The pattern is formed by using normal phenol organic photo resist, and thereafter an insulation film (e.g. Al2O3) is deposited on the substrate 1 with the resist pattern 2 by a vacuum deposition method at a substrate temperature less than approx. 300 deg.C, the deposition temperature for the organic photo resist in vacuum. Afterwards, it is kept in an atmospheric furnace at 450 deg.C in oxygen for an hour or more, and then the resist 2 is removed by combustion and evaporation, resulting in the formation of the pattern.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method of forming an oxide superconductor circuit, which is related to a method of using a resist material in forming a wiring pattern or an insulating layer in the process of forming an oxide superconductor circuit.

Conventionally, organic photoresists have been used as resists for forming circuits of oxide superconductors.
When the substrate temperature rises, it solidifies and becomes difficult to remove with ordinary glue mover liquid. To fabricate a superconductor circuit, it is necessary to sequentially form thin films such as the upper electrode, extraction electrode, and insulating layer, but the above-mentioned restriction that the substrate temperature cannot be raised in this process is due to the film formation time. This leaves defects in the circuit system, such as an increase in bond strength or a decrease in the adhesive strength between films, and causes element deterioration due to thermal cycling between cryogenic temperatures and room temperature.

The present invention is characterized by a method of using a resist that focuses on the chemical stability of an oxide thin film, and its purpose is to provide a method for forming an oxide superconductor circuit that performs a lift-off process at a high substrate temperature. be.

That is, to summarize the present invention, the first aspect of the present invention is that in a method for forming an oxide superconductor circuit, a pattern of an organic photoresist is formed on a substrate or a patterned substrate, and then a pattern of the organic photoresist is formed. Depositing an oxide thin film in vacuum on the patterned substrate at a high temperature below the decomposition temperature, and then depositing the organic photoresist in a high temperature oxygen atmosphere.
The present invention relates to a method for forming an oxide superconductor circuit, which is characterized in that a pattern of an oxide thin film is formed by removal by combustion and evaporation.

The second invention of the present invention is a method for forming an oxide superconductor circuit, in which a thin film pattern of gold or zinc oxide is formed on a substrate or a patterned substrate, and then the gold or zinc oxide is reacted. An oxide superconductor circuit characterized in that an oxide thin film is deposited on the patterned substrate at a high temperature below that temperature, and then the gold or zinc oxide is melted away to form a pattern of the oxide thin film. Regarding the formation method.

The oxide thin film is prepared using a high-temperature oxidizing atmosphere, a diluent such as sulfuric acid, nitric acid, phosphoric acid, or a gold etchant.
It has the property of being stable in aqueous solutions. The present invention was achieved by researching ways to use resists that take advantage of this feature.

Examples of oxide superconductors in the present invention include BaP'b (1
-X)13j, (X)03 (however, 0.05 rix
<0.30). Examples of oxides that form oxide thin films are At203, BaPb Bi03 (
However, there is 0 (y) y (hereinafter abbreviated as BPB).

Methods for forming the thin film pattern of gold or zinc oxide in the second aspect of the present invention include a method using an organic photoresist and a method using a mask pattern. An example of a gold removal solution is an aqueous solution of iodine and potassium iodide, and an example of a zinc oxide removal solution is a dilute acid.

According to the present invention, it is possible to use a resist even at high substrate temperatures, so the lift-off method can be applied to the formation of oxide superconductor circuits.

For this reason, it is effective in forming an insulating layer to separate oxide superconductor layers when manufacturing a multilayer circuit using oxide superconductors, or in multilayering when etching is not applicable when the materials are of the same type.

The present invention will be explained in more detail with reference to Examples below, but the present invention is not limited to these Examples.

Note that FIGS. 1 and 2 of the attached drawings are process diagrams showing one embodiment of the method of the present invention.

Example 1 A circuit was formed according to the steps shown in FIG.

In FIG. 1, 1 represents a substrate (including a patterned substrate), 2 represents an organic photoresist, and 6 represents an oxide thin film.

First, use a conventional phenolic organic photoresist (for example, A
Step a to form a pattern using Z 135 (1)
), then the decomposition temperature of the organic photoresist in vacuum! A BPB film or insulating pA (for example, Az20a) is deposited on the substrate 1 with the resist pattern 2 by vacuum evaporation at a substrate temperature of less than about 100° C. (step b). Thereafter, this is held in an atmosphere furnace at 450° C. in oxygen for one hour or more, and the resist of step 2 is burnt and evaporated to be removed and a pattern is formed (Step C).

The resist in step b solidifies and cannot be removed with a normal stripping solution, but the pattern shape and composition do not change at all, and it is vaporized by the high temperature oxygen atmosphere in step C, and at that stage it adheres to the organic photoresist 2 soil. The deposited film 3 that has been removed is also removed at the same time.

On the other hand, since the deposited film on the substrate is an oxide that is stable in a high-temperature oxygen atmosphere, its characteristics do not change in the step C, making it possible to form the desired pattern with an accuracy of several μm.

Example 2 A circuit was formed according to the steps shown in FIG.

In FIG. 2, 1 to 6 have the same meanings as in FIG. 1, 31 means a BPB thin film, and 4 means an inorganic resist film (gold or zinc oxide).

First, a BPB thin film is patterned on the substrate (step a).
), then the entire upper part is covered with an inorganic resist (step b). Among inorganic resists, gold is deposited by vacuum evaporation, and zinc oxide is deposited by magnetron sputtering.
It is formed to have a thickness of about 1 μm. Thereafter, an organic/cyst pattern is formed using a conventional photorinography method (Step C).
). Next, the inorganic resist is patterned by an etching method, and then the organic resist is removed (step d).

For gold, a mixed aqueous solution of iodine and potassium iodide (KI
: I2:H20=207.107.1oor), and for zinc oxide dilute acid (e.g. 2% H2804,2
HNO3, 2% H3P04) is suitable as an etching solution.

Next, an insulating layer (for example, At203) or an oxide superconductor layer is deposited by vacuum evaporation at a high substrate temperature (about 300° C.) that provides sufficient adhesive strength over the entire two surfaces. In this case, the above-mentioned inorganic resist 4 does not react with BPB or the insulating layer and is stable. Finally, the desired pattern is obtained by removing the inorganic resist (step f)
.

The etching solution used in step d can be used as the inorganic resist removing agent, and the inorganic resist can be completely removed within a few minutes. In contrast to the above-mentioned etching solution, BPB is stable even when immersed for several hours, and the above-mentioned process allows formation of a circuit with an intended function with an accuracy of several micrometers.

As explained in detail above, according to the present invention, the lift-off method can be applied to the formation of oxide superconductor circuits, and the lift-off method can be applied to the formation of an insulating layer that separates oxide superconductor layers, or the etching method can be applied to It has the advantage of being effective for multi-layering when it cannot be applied.

[Brief explanation of the drawing]

FIG. 1 is a process diagram for using an organic resist, and FIG. 2 is a process diagram for using an inorganic resist. 1: Substrate, 2: Organic photoresist film, 3: Insulating film or B
PB film, 31: BPB film, 4: Inorganic resist No. / Fig. 2

Claims (1)

[Claims] 1. In a method for forming an oxide superconductor circuit, a pattern of an organic photoresist is formed on a substrate or a patterned substrate, and then the patterned substrate is heated to a high temperature below the decomposition temperature of the organic photoresist. An oxide superconductor characterized in that an oxide thin film is deposited thereon in vacuum, and then the organic photoresist is removed by combustion and evaporation in a high-temperature oxygen atmosphere to form a pattern of the oxide thin film. Body circuit formation method. 2. In a method for forming an oxide superconductor circuit, a thin film pattern of gold or zinc oxide is formed on a substrate or a patterned substrate, and then the patterned film is heated at a high temperature below the reaction temperature of the gold or zinc oxide. A method for forming an oxide superconductor circuit, comprising depositing an oxide thin film on a substrate, and then dissolving and dissolving the gold or zinc oxide to form a pattern of the oxide thin film.