JPS6237467B2 - - Google Patents
Info
- Publication number
- JPS6237467B2 JPS6237467B2 JP9997780A JP9997780A JPS6237467B2 JP S6237467 B2 JPS6237467 B2 JP S6237467B2 JP 9997780 A JP9997780 A JP 9997780A JP 9997780 A JP9997780 A JP 9997780A JP S6237467 B2 JPS6237467 B2 JP S6237467B2
- Authority
- JP
- Japan
- Prior art keywords
- magnetic field
- loops
- bubble memory
- defective
- holding
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
- 230000015654 memory Effects 0.000 claims description 29
- 230000002950 deficient Effects 0.000 claims description 21
- 238000012360 testing method Methods 0.000 claims description 12
- 230000006866 deterioration Effects 0.000 claims description 3
- 230000006870 function Effects 0.000 claims description 2
- 230000007257 malfunction Effects 0.000 description 9
- 230000007547 defect Effects 0.000 description 7
- 238000004519 manufacturing process Methods 0.000 description 4
- 238000012216 screening Methods 0.000 description 4
- 238000010586 diagram Methods 0.000 description 2
- 238000011160 research Methods 0.000 description 2
- 230000003247 decreasing effect Effects 0.000 description 1
- 238000001514 detection method Methods 0.000 description 1
- 230000007787 long-term memory Effects 0.000 description 1
- 238000000034 method Methods 0.000 description 1
- 230000006403 short-term memory Effects 0.000 description 1
- 238000012546 transfer Methods 0.000 description 1
Classifications
-
- G—PHYSICS
- G11—INFORMATION STORAGE
- G11C—STATIC STORES
- G11C29/00—Checking stores for correct operation ; Subsequent repair; Testing stores during standby or offline operation
- G11C29/04—Detection or location of defective memory elements, e.g. cell constructio details, timing of test signals
-
- G—PHYSICS
- G11—INFORMATION STORAGE
- G11C—STATIC STORES
- G11C29/00—Checking stores for correct operation ; Subsequent repair; Testing stores during standby or offline operation
- G11C29/003—Checking stores for correct operation ; Subsequent repair; Testing stores during standby or offline operation in serial memories
Description
【発明の詳細な説明】
本発明は量産された磁気バブルメモリチツプあ
るいは磁気バブリメモリパツケージのメモリ動作
試験を行い、弱欠陥ループをも比較的短時間に検
出できる磁気バブルメモリ選別試験機に関する。DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a magnetic bubble memory sorting tester capable of testing the memory operation of mass-produced magnetic bubble memory chips or magnetic bubble memory packages and detecting even weak defective loops in a relatively short time.
第１図はメイジヤマイナ方式磁気バブルメモリ
チツプの構成例を示し、図中、ｍは情報を貯える
マイナループ、RMLは読出し情報を転送するリ
ードメイジヤライン、WMLは書込み情報を転送
するライトメイジヤライン、Ｄは磁気バブル検出
を電気信号にして送出するバブル検出器、Ｇは情
報を書込む磁気バブル発生器、Ｒはマイナループ
ｍの情報をリードメイジヤラインRMLに複写す
るレプリケートゲート、Ｓはライトメイジヤライ
ンWML上の情報とマイナループ中の情報とを入
替えるスワツプゲートである。この様に磁気バブ
ルメモリチツプは多数のマイナループｍを有し、
このマイナループｍの数ｌは、例えば’256kbチ
ツプの場合250〜300個、1Mbチツプの場合550〜
600個で、チツプ全体の面積の大部分はマイナル
ープによつて占められる。磁気バブルメモリチツ
プを実際に製造する際、全く無欠陥のチツプばか
りを製造することは困難で、多くのチツプは大抵
いくつかの欠陥を持つが、欠陥はチツプ内でラン
ダムに生ずるため、欠陥のほとんどすべてはチツ
プ面積の大部分を占めるマイナループ上に生ず
る。すなわち製造された多くのチツプは欠陥のあ
るマイナループ（欠陥ループ）をいくつか持つ。
第１図中のｄは、この様な欠陥を示す。この欠陥
ループ対策として、マイナループｍの数ｌを実際
に使用する必要ループ数ｂよりあらかじめ余分に
ｓ個設けておき、１メモリチツプ内の欠陥ループ
数がｓ個以内のチツプは合格として許容し量産歩
留を上げることが広く行われている。余分に設け
るｓ個のマイナループをスペアループと呼び、そ
の数は、通常、256kbチツプの場合に20〜30個、
1Mbチツプの場合40〜60個である。 Fig. 1 shows an example of the configuration of a magnetic bubble memory chip using the magia-minor method. A bubble detector that converts magnetic bubble detection into an electric signal and sends it out; G is a magnetic bubble generator that writes information; R is a replicate gate that copies information from the minor loop m to the read mager line RML; S is on the light mager line WML. This is a swap gate that swaps information with information in the minor loop. In this way, the magnetic bubble memory chip has a large number of minor loops m,
The number of minor loops m is, for example, 250 to 300 for a 256kb chip, and 550 to 300 for a 1Mb chip.
600, and the majority of the total area of the chip is occupied by the minor loop. When actually manufacturing magnetic bubble memory chips, it is difficult to manufacture completely defect-free chips, and most chips usually have some defects, but since defects occur randomly within the chip, it is difficult to manufacture chips that are completely defect-free. Almost all occur on the minor loop, which occupies most of the chip area. That is, many manufactured chips have some defective minor loops.
d in FIG. 1 indicates such a defect. As a countermeasure against defective loops, the number l of minor loops m is set in advance by an extra s than the required number of loops b actually used, and chips with the number of defective loops in one memory chip within s are accepted as acceptable, and mass production is started. It is widely practiced to raise the bar. The extra s minor loops provided are called spare loops, and the number is usually 20 to 30 for a 256kb chip.
For a 1Mb chip, the number is 40 to 60.
したがつて磁気バブルメモリ選別試験機は、磁
気バブルメモリチツプにメモリ動作を実行させ、
誤動作する欠陥ループ数を調べる機能を持ち、欠
陥ループ数がｓ個以内ならば合格、（ｓ＋１）個
以上ならば不合格とするような構成になつてい
る。 Therefore, the magnetic bubble memory sorting tester allows magnetic bubble memory chips to perform memory operations,
It has a function of checking the number of defective loops that malfunction, and is configured to pass if the number of defective loops is s or less, and to fail if it is (s+1) or more.
近年磁気バブルメモリ容量を大幅に増加するた
め、メモリチツプは高密度化され、それに伴い磁
気バブル径も、３μｍ程度から２μｍ程度に微小
化され、マイナループを形成する基本転送路のサ
イズも12μｍ程度から８μｍ程度へと高集積化さ
れつつあり、今後更に磁気バブルメモリチツプは
高密度化される傾向にある。 In recent years, in order to significantly increase the capacity of magnetic bubble memory, memory chips have become highly dense, and the diameter of magnetic bubbles has accordingly been miniaturized from about 3 μm to about 2 μm, and the size of the basic transfer path forming the minor loop has also decreased from about 12 μm to 8 μm. In the future, magnetic bubble memory chips will tend to become even more highly integrated.
磁気バブル径が３μｍ程度以上の、これまでの
磁気バブルメモリチツプでは余り問題にならなか
つたが、磁気バブル径が２μｍ程度以下の微小バ
ブルを用いた高密度化された磁気バブルメモリチ
ツプでは、後述の弱欠陥ループが存在し、長時間
のメモリ動作試験を行わなければメモリチツプの
選別ができないという問題が重大になつてきた。 This has not been much of a problem with conventional magnetic bubble memory chips with magnetic bubble diameters of about 3 μm or more, but with high-density magnetic bubble memory chips using microbubbles with magnetic bubble diameters of about 2 μm or less, the problem will be discussed later. The problem has become serious that memory chips cannot be selected without long-term memory operation tests due to the existence of weak defective loops.
すなわち選別試験機で欠陥ループを調べる際、
メモリ動作を実行させると直ちに誤動作する明確
な欠陥ループ以外に、短時間のメモリ動作では正
常に動作するが、長時間メモリ動作させている
と、たまに誤動作する欠陥ループが存在すること
がわかつた。以後、直ちに誤動作する欠陥ループ
を強欠陥ループ、長時間動作後たまに誤動作する
欠陥ループを弱欠陥ループと呼ぶこととする。こ
の様な弱欠陥ループを含む磁気バブルメモリチツ
プを従来の選別試験機で選別しようとすれば長時
間のメモリ動作試験を要し、選別試験効率が悪く
なつてしまう。 In other words, when examining defective loops with a screening tester,
In addition to clearly defective loops that malfunction as soon as a memory operation is executed, we have found that there are also defective loops that operate normally during short-term memory operations but occasionally malfunction when memory operations are performed for long periods of time. Hereinafter, a defective loop that immediately malfunctions will be referred to as a strongly defective loop, and a defective loop that occasionally malfunctions after a long period of operation will be referred to as a weakly defective loop. If a conventional sorting test machine were to be used to sort magnetic bubble memory chips containing such weakly defective loops, a long memory operation test would be required, resulting in poor sorting test efficiency.
本発明の目的は、比較的短時間で、弱欠陥ルー
プの試験可能な磁気バブルメモリ選別試験機を提
供することにある。 An object of the present invention is to provide a magnetic bubble memory sorting tester that can test weakly defective loops in a relatively short time.
上記目的を達成するために本発明においては、
スタートストツプ動作による特性劣化抑制のため
に加えていた従来公知のホールデイング磁界を脈
動させながらメモリ動作を行わせ、選別試験を行
うこととした。本発明者が実験研究の結果、ホー
ルデイング磁界を脈動させることにより弱欠陥ル
ープの誤動作が加速されることがわかつたからで
ある。 In order to achieve the above object, in the present invention,
We decided to conduct a selection test by performing memory operation while pulsating a conventionally known holding magnetic field that was applied to suppress characteristic deterioration due to start-stop operation. This is because, as a result of experimental research, the present inventor found that pulsating the holding magnetic field accelerates the malfunction of the weak defect loop.
バブル径が２μｍ程度以下の微小バブルを用い
た高密度バブルメモリについて、本発明者が実験
研究の結果、まず次の特性が認められた。 As a result of experimental research conducted by the present inventor regarding a high-density bubble memory using microbubbles with a bubble diameter of approximately 2 μm or less, the following characteristics were first observed.
(a) チツプを駆動する回転磁界をオン、オフした
メモリ動作（スタートストツプ動作）を行わせ
ると、弱欠陥ループは誤動作しやすくなる。(a) When a memory operation is performed in which the rotating magnetic field that drives the chip is turned on and off (start-stop operation), weakly defective loops tend to malfunction.
(b) データパターン依存性が強く、データパター
ンを各種組合せて変化させると、弱欠陥ループ
が誤動作しやすくなる。(b) Data pattern dependence is strong, and when data patterns are changed in various combinations, weakly defective loops tend to malfunction.
しかし、これらは強欠陥ループについても同
様であり、従来の選別試験機でも上記(a)、(b)の
特性を考慮して試験しており、これらだけでは
弱欠陥ループ動作試験時間短縮は不十分であつ
た。そのため本発明者は、弱欠陥ループの特性
を更に詳細に調べた結果、つぎの様なことがわ
かつた。 However, these are the same for strong defect loops, and conventional screening testers also take into account the characteristics (a) and (b) above, and these alone cannot shorten the operation test time for weak defect loops. It was enough. Therefore, the inventor investigated the characteristics of the weakly defective loop in more detail and found the following.
(c) ホールデイング磁界を脈動させることによ
り、弱欠陥ループの誤動作が大きく加速され
る。本発明はこの(c)の特性を利用したのであ
る。(c) By pulsating the holding magnetic field, the malfunction of the weak defect loop is greatly accelerated. The present invention utilizes this characteristic (c).
以下ホールデイング磁界について説明する。磁
気バブルメモリは、動作時のみ回転磁界が加えら
れ（オン）、動作しない時は回転磁界が加えられ
ない（オフ）使用法をとる。すなわち回転磁界の
オン、オフが繰返される。これをスタートストツ
プ動作とよぶ。第２図はこの時の回転磁界ＨRの
ベクトル軌跡の一例を示す。スタート時の回転磁
界の方向と、ストツプ時の回転磁界の方向とは同
方向で、その方向はバブルメモリチツプによつて
定まる特定方向になつている。この方向はスター
トストツプ方向と呼ばれ、第２図に示した例の場
合はプラスＹ方向である。バブルメモリチツプに
スタートストツプ動作をさせると動作特性が劣化
する。この劣化を最小に抑えるために、バブルメ
モリチツプの面内、スタートストツプ方向に、第
３図に示すような大きさ数エルステツド程度の直
流磁界を加えることが従来一般に行われており、
これがホールデイング（holding）磁界Ｈhであ
る。従来の選別試験機でも一定に保つたホールデ
イング磁界を加えながら動作させていた。 The holding magnetic field will be explained below. A magnetic bubble memory is used in such a way that a rotating magnetic field is applied only when it is in operation (ON), and not applied (OFF) when it is not in operation. That is, the rotating magnetic field is repeatedly turned on and off. This is called start-stop operation. FIG. 2 shows an example of the vector locus of the rotating magnetic field H R at this time. The direction of the rotating magnetic field at the start and the direction of the rotating magnetic field at the stop are the same, and the direction is a specific direction determined by the bubble memory chip. This direction is called the start-stop direction, and in the example shown in FIG. 2, it is the plus Y direction. When a bubble memory chip is subjected to start-stop operation, its operating characteristics deteriorate. In order to minimize this deterioration, it has been common practice to apply a DC magnetic field of several Oersteds in the plane of the bubble memory chip in the start-stop direction, as shown in Figure 3.
This is the holding magnetic field H h . Conventional sorting testers were operated while applying a holding magnetic field that was kept constant.
第４図は本発明に係る脈動するホールデイング
磁界Ｈhのベクトル軌跡の例を示す。第４図に示
した例では、ホールデイング磁界ベクトルは方向
不変で、大きさだけ脈動している。第５図は本発
明の他の実施例におけるホールデイング磁界Ｈh
のベクトル軌跡を示し、磁界ベクトルの方向と大
きさの両方が同時に変つている。このような変動
するホールデイング磁界は、回転磁界発生用の直
交する２個のコイル（ＸコイルとＹコイル）に脈
動ホールデイング磁界用のバイアス電流を流すこ
とによつて容易に得られる。 FIG. 4 shows an example of the vector locus of the pulsating holding magnetic field H h according to the present invention. In the example shown in FIG. 4, the holding magnetic field vector remains unchanged in direction and pulsates in magnitude. FIG. 5 shows the holding magnetic field H h in another embodiment of the present invention.
, where both the direction and magnitude of the magnetic field vector are changing simultaneously. Such a fluctuating holding magnetic field can be easily obtained by passing a bias current for a pulsating holding magnetic field through two orthogonal coils (X coil and Y coil) for generating a rotating magnetic field.
以上説明したように本発明によれば、弱欠陥ル
ープを含んだ磁気バブルメモリの選別試験を比較
的短時間に実行できるようになり、選別試験効率
が大幅に向上する。 As explained above, according to the present invention, it becomes possible to carry out a screening test for magnetic bubble memories containing weakly defective loops in a relatively short time, and the efficiency of the screening test is greatly improved.
第１図は磁気バブルメモリチツプ構成例図、第
２図はスタートストツプ動作する時の回転磁界ベ
クトルの軌跡の例を示す図、第３図は従来の磁気
バブルメモリ選別試験機におけるホールデイング
磁界のベクトル図、第４図は本発明に係る大きさ
だけ脈動するホールデイング磁界ベクトル軌跡
図、第５図は本発明に係る大きさと方向が両方と
も脈動するホールデイング磁界ベクトル軌跡図で
ある。
ＨR……回転磁界、Ｈh……ホールデイング磁
界。
Figure 1 shows an example of the structure of a magnetic bubble memory chip, Figure 2 shows an example of the locus of the rotating magnetic field vector during start-stop operation, and Figure 3 shows the holding magnetic field in a conventional magnetic bubble memory sorting tester. FIG. 4 is a vector locus diagram of a holding magnetic field pulsating in magnitude according to the present invention, and FIG. 5 is a vector locus diagram of a holding magnetic field pulsating in both magnitude and direction according to the present invention. H R ...Rotating magnetic field, H h ...Holding magnetic field.
Claims (1)
ため、ホールデイング磁界を加えながらメモリ動
作を行わせ、欠陥ループ数を検出する機能を備え
た磁気バブルメモリ選別試験機において、選別試
験動作時、ホールデイング磁界を脈動させるよう
にしたことを特徴とする磁気バブルメモリ選別試
験機。 ２ ホールデイング磁界の大きさと方向の両方を
脈動させるようにした特許請求の範囲第１項記載
の磁気バブルメモリ選別試験機。[Scope of Claims] 1 In order to suppress characteristic deterioration due to start-stop operation, a sorting test was carried out in a magnetic bubble memory sorting tester equipped with a function of performing memory operation while applying a holding magnetic field and detecting the number of defective loops. A magnetic bubble memory sorting test machine characterized by a holding magnetic field that pulsates during operation. 2. The magnetic bubble memory sorting tester according to claim 1, wherein both the magnitude and direction of the holding magnetic field are pulsated.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP9997780A JPS5727480A (en) | 1980-07-23 | 1980-07-23 | Tester for magnetic bubble memory selection |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP9997780A JPS5727480A (en) | 1980-07-23 | 1980-07-23 | Tester for magnetic bubble memory selection |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS5727480A JPS5727480A (en) | 1982-02-13 |
| JPS6237467B2 true JPS6237467B2 (en) | 1987-08-12 |
Family
ID=14261719
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP9997780A Granted JPS5727480A (en) | 1980-07-23 | 1980-07-23 | Tester for magnetic bubble memory selection |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS5727480A (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH0381197U (en) * | 1989-12-08 | 1991-08-20 |
Families Citing this family (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS59217287A (en) * | 1983-05-25 | 1984-12-07 | Fujitsu Ltd | Testing method of bubble memory element |
| EP0201007A3 (en) * | 1985-04-26 | 1989-03-22 | Hitachi, Ltd. | Method for measuring holding field of a magnetic bubble memory module using picture-frame-core |
| JPS6314392A (en) * | 1986-07-05 | 1988-01-21 | Fujitsu Ltd | Controller for magnetic bubble memory device |
-
1980
- 1980-07-23 JP JP9997780A patent/JPS5727480A/en active Granted
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH0381197U (en) * | 1989-12-08 | 1991-08-20 |
Also Published As
| Publication number | Publication date |
|---|---|
| JPS5727480A (en) | 1982-02-13 |
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