Miscellaneous active electrical nonlinear devices – circuits – and – Specific signal discriminating without subsequent control – By amplitude
Reexamination Certificate
2000-03-17
2001-11-20
Wells, Kenneth B. (Department: 2816)
Miscellaneous active electrical nonlinear devices, circuits, and
Specific signal discriminating without subsequent control
By amplitude
C327S143000, C327S198000
Reexamination Certificate
active
06320428
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to a semiconductor integrated circuit device which comprises a data storage section, formed inside a chip, for storing desirable mode setting data corresponding to products of a plurality of types, redundancy data, and so on.
Examples of product types in a semiconductor integrated circuit device are
(1) a product type in which the layout of pads depends on a package such as TSOP (Thin Small Outline Package)/SOP (Small Outline Package), and the locations of pads to be used are switched,
(2) a product type in which parallel data have different bit lengths such as ×4, ×8, and ×16, and the numbers of I/O blocks and sense amplifiers to be activated change in accordance with a bit length, and
(3) a product type in which addressing changes such that the top and bottom of an address for designating an irregular block are switched in an irregular-block product in a flash EEPROM.
In the semiconductor integrated circuit device having a plurality of different modes, the operation mode of the device must be determined by some method.
In general, either of the master slice or bonding option methods is conventionally selected in order to develop one mask set into the types of products having a plurality of different modes.
In the master slice method, different modes are switched by exchanging, e.g., Al masks. This method is generally used in developing one mask set into a plurality of mode types.
On the other hand, the bonding option method uses an input signal from a dummy pad to select a different mode. A power supply voltage or ground potential is applied to the dummy pad to determine the mode of an integrated circuit by either potential.
A semiconductor integrated circuit device in which a plurality of product types are developed by the bonding option method is disclosed in, e.g., the following reference:
EUROPEAN PATENT Publication Number 0 476 282 A2 (lines 29-44, p. 10,
FIG. 1
n
and the like).
In the bonding option method, no plurality of masks need be prepared compared to the master slice method, and data need not be managed in correcting the mask.
In the master slice method, one product type requires one mask. Assume that four product types are simultaneously developed, and the product type is switched by Al masks. If a given Al mask must be corrected, four Al masks must be corrected, resulting in high mask cost. If the number of times of correction is large, the correction contents may not be completely managed. All functions corresponding to the corrected masks must be checked, and the evaluation is cumbersome.
In the bonding option method, a power supply or ground potential is applied to a dummy pad for determining the contents of a device. Therefore, the dummy pad must be arranged between power supply pins or ground pins. Alternatively, the bonding option exclusively requires a pad connected to the power supply and a pad connected to the ground adjacent to the dummy pad. Since the bonding option method requires a large number of extra pads to lead to an increase in chip area, this method cannot cope with so many modes.
Semiconductor integrated circuit devices designed in consideration of the above technology and comprising data storage sections that store mode setting data corresponding to products of a plurality of types, are disclosed, for example, in the following publications:
Jpn. Pat. Appln. KOKAI Publication No. 2-116084 (the description between the fourteenth line of the lower left column of page 2 and the eleventh line of the lower right column of the same page, and FIG. 2); and
Jpn. Pat. Appln. KOKAI Publication No. 6-243677 (the descriptions in paragraphs [0044] and [0102], and FIG. 10)
In the semiconductor integrated circuit device disclosed in each of these publications, mode setting data are stored in a nonvolatile transistor. Due to this feature, the semiconductor integrated circuit device enables one mask set to be developed into a plurality of product types, eliminates the need for extra pads, and does not therefore require an increased chip area.
The data storage section, which includes a nonvolatile transistor, stores mode setting data corresponding to products of a-plurality of types. Accordingly, the data storage section requires very high reliability.
However, the two Japanese KOKAI publication No. 2-116084 and No. 6-243677 do not disclose any measures that can be taken to improve the reliability of the data storage section.
BRIEF SUMMARY OF THE INVENTION
It is the first object of the present invention to increase the reliability of a data memory portion for storing, for example, desired mode setting data corresponding to a plurality of product types to data memory portion being arranged with a chip.
To achieve the first object, according to the present invention, an internal power supply generated within the chip is used as the power supply of the data memory portion instead of an external power supply.
More specifically, in the present invention, by using the internal power supply generated within the chip as the power supply of the data memory portion, a malfunction of the data memory portion caused by, e.g., fluctuations in voltage of the external power supply is prevented.
To further suppress an increase in chip area, the data memory portion requires the same micro-lithography technique as that applied to another integrated circuit portion formed within the same chip. For example, in the data memory portion, a power supply voltage must be decreased.
However, if the power supply voltage is decreased, data may not be correctly read out from the data memory portion. The data memory portion stores, for example, desired mode setting data corresponding to a plurality of product types to determine the type of product. For this reason, high precision is required for the reading of data from the data memory portion.
It is the second object of the present invention to read out data from the data memory portion at high precision even if the power supply voltage is decreased.
To achieve the second object, according to the present invention, data is read out from the data memory portion at a boosted voltage higher than the power supply voltage.
That is, in the present invention, data is read out from the data memory portion at the boosted voltage higher than the power supply voltage. With this setting, even if the data memory portion stores data using a nonvolatile memory cell, the data read precision is increased by increasing the difference between the threshold voltage of the nonvolatile memory cell in an “ON” state, and the voltage of the control gate.
When the power supply voltage becomes low, it may happen that the internal power supply voltage is not high enough to operate the data storage section in a reliable manner, particularly when the system is turned on. The data storage section stores desirable mode setting data corresponding to products of a plurality of types, and the type of a product is determined on the basis of the mode setting data. Therefore, the data storage section must be operated as soon as the system is turned on. The data storage section must be reliably operated even when the internal power supply voltage is not very high, such as the time when the system has just been turned on.
It is the third object of the present invention to correctly operate the data memory portion upon, particularly, power-on.
To achieve the third object, in the present invention, a circuit for detecting the voltage of the internal power supply and outputting a signal representing that the voltage of the internal power supply increases to a voltage high enough to correctly operate the data memory portion is arranged within the chip. The operation of the data memory portion is enabled by a signal from this circuit.
In other words, in the present invention, the data memory portion is operated only when the voltage of the internal power supply increases to a voltage high enough to correctly operate the data memory portion. As a result, the data memory portion correctl
Atsumi Shigeru
Banba Hironori
Kuriyama Masao
Saito Hidetoshi
Taura Tadayuki
Banner & Witcoff , Ltd.
Kabushiki Kaisha Toshiba
Wells Kenneth B.
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