JPS58208988A - Method for testing deffective loop mask - Google Patents

Abstract

PURPOSE:To test a magnetic bubble element of major/minior loop constitution suitably in excellent way, by masking a minor loop verified as defective at the previous test for testing the element this time. CONSTITUTION:When a minor loop 13-3 is tested as defective by means of the demagnetization test or the like for example, the loop 13-3 is masked for the next temperature test and the test is conducted without writing the magnetic bubble. If a minor loop 13-1 is defective, then the loops 13-3, 13-1 are masked at the next low temperature test. Thus, the generation of mis-judgement taking a good minor loop as defective because of the disturbance of the defective minor loops is prevented, and the magnetic bubble element of the major/minor loop constitution is tested suitably in excellent way.

Description

DETAILED DESCRIPTION OF THE INVENTION (1) Technical Field of the Invention The present invention relates to an improvement in a testing method for magnetic bubble memories used as storage devices in electronic computing devices or terminals thereof.

(2) Background of the technology Magnetic bubble memory has various characteristics such as non-volatility, high storage density, low power consumption, small size and light weight, and is also extremely expensive because it is a solid-state device that does not contain any mechanical elements. It is reliable and is expected to have a promising future as a large capacity memory. This magnetic bubble memory utilizes the fact that magnetic bubbles can move freely in a magnetic thin film having G-axis anisotropy due to a magnetic field.As shown in FIG. It is composed of rotating magnetic field generating coils 2 and 2' for driving, bias magnetic field generating foundation stones 3 and 3' for stably holding the bubble, and the like.

The memory element 1 is made by forming a thin film of magnetic garnet by liquid phase epitaxial growth on a gadolinium-gallium-garnet single crystal substrate, for example, and forming a pattern such as a half-disk as shown in FIG. A bubble transfer path is formed. The configuration of this bubble transfer path includes a serial loop configuration,
There is a major minor loop configuration. FIG. 3 is a diagram showing an example 2 of a measure minor lube configuration, and includes a write measure line 5 having a bubble generator 4, a read measure line 7 having a bubble detector 6, and a transformer 7 agate. 8 and a plurality of minor lubes 10-1 to 10-n connected by a replicate gate 9.

(3) Prior art and problems In such magnetic bubble memory elements, variations in characteristics occur due to variations in manufacturing conditions.

Therefore, it is necessary to examine the operating characteristics of each individual. To examine this operating characteristic, there are demagnetization tests that look at the behavior while gradually lowering the bias magnetic field value, high temperature tests that look at the behavior at high temperatures, and low temperature tests that look at the behavior at low temperatures.

Conventionally, in such tests, bubbles were written in all minor lubes, and minor lubes whose read information did not match the written data were treated as defective minor lubes. This method has a drawback that if there is a defective minor loop that interferes with other minor loops because a bubble is written in a certain minor loop, the disturbed minor loop is also determined to be a defective minor loop.

(4) Purpose of the Invention In view of the above-mentioned conventional drawbacks, it is an object of the present invention to provide a test method for a magnetic bubble memory element having a major-minor loop configuration that does not erroneously determine a good minor loop as a bad loop. It is.

(5) Structure and object of the invention According to the present invention, in a series of test methods for testing the operating characteristics of a magnetic bubble memory with a major-minor loop configuration, a defective loop in the minor loop found in a pre-test process is This is achieved by providing a defective loop mask testing method that is characterized in that the process is tested without writing bubbles through masking.

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

FIG. 4 is a diagram for explaining the defective loop mask testing method according to the present invention. In the figure, 11 is a major line for writing, 12 is a major line for reading, 11. ~
13-n each indicate a minor loop.

In the test method according to the present invention, if loop 13-3 in the mana lubricant is found to be defective by, for example, a demagnetization test, the defective loop 13-3 is
No bubbles are written in loop 8, but bubbles are written only in other loops to perform the test.

If, for example, the loop 13-1 is found to be defective, the next low-temperature test is performed without writing any bubbles into both the loops 13-3 and 13-1.

In this way, the test method of the present invention is such that a defective loop found in the test in the pre-process is masked and not used in the test in the post-process.

This prevents problems such as writing a bubble in a bad loop that affects other loops, such as a bubble escaping from a bad loop and invading other loops, or causing other good loops to become defective. .

(7) Effects of the Invention As explained in detail above, the defective loop mask testing method according to the present invention is performed by masking and testing previously known defective minor loops in a magnetic bubble memory with a major minor loop configuration. Even if there is a defective loop that may cause interference to others, it will not interfere with others because the bubbles will be written in, so it will have a great effect in that it will be possible to reduce the number of defective minor loops.

[Brief explanation of drawings]

Fig. 1 is a diagram for explaining a conventional magnetic bubble memory device, Fig. 2 is a diagram showing an example of a bubble transfer path, and Fig. 3 is a diagram for explaining a major-minor lube configuration of a magnetic bubble memory. , and FIG. 4 are diagrams for explaining the defective loop mask testing method according to the present invention. In the drawings, 11 is a major line for writing, 12 is a major line for reading, and 13-1 to 13-n are minor loops. are shown respectively.Figure 3

Claims (1)

[Claims] 1. In a series of test methods to test the operating characteristics of a magnetic bubble memory with a major-minor lube configuration, defective loops among the minor loops found in the previous test process are masked during the next test process, and the test is performed without writing bubbles. A defective loop mask testing method characterized by performing.