JPS6012679A - Information memory device - Google Patents

Abstract

PURPOSE:To provide an auxiliary power source built-in memory device having long life and compact size by incorporating all solid state secondary batteries in a resin package. CONSTITUTION:A solid state unit cell 1 measuring 5X5X0.8mm. and a semiconductor memory device chip 2 are fixed on the both sides of a lead frame 3, and electrodes 5 for connecting unit cells in series are arranged, and they are incorporated in a resin package 6 which also serves as a battery container. A unit cell pellet consists of a positive layer 7 comprising positive mix of the mixture of Cu0.6V2O5 powder and Cu ion conductive electrolyte of RbCu4I1.5Cl3.5 powder and graphite, an electrolyte layer 8 comprising Cu ion conductive solid electrolyte of RbCu4I1.5Cl3.5, and a negative layer 9 comprising negative mix of the mixture of Cu2S powder, Cu powder, and Cu ion conductive solid electrolyte RbCu4I1.5Cl3.5 powder. By packaging together memory device and batteries, volatile memory device which loses memory stored when it is separated from power source can be converted into vertual nonvolatile memory device.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to information storage devices such as semiconductor memory devices, in particular,
The present invention relates to an information storage element having an integrated power supply for pull-up.

The structure of conventional examples and their problems The use of small batteries in electronic equipment depends on the development of high-density information storage elements such as conductive memory elements.
Note 1) In order to maintain retention even when the main power supply is cut off, it is increasingly being used as an auxiliary power source for the memory buffer knobs in the arm.

As a battery for auxiliary power supply, even if the discharge capacity and output current are small, it is necessary to use a battery that does not impair retention when attaching or detaching the memory element from the equipment or board (note 1). It is desirable that the memory element and the force be integrated without being combined.

Conventionally, as such an auxiliary power source, a coin-shaped or button-shaped primary battery is mainly used, but the battery and memory element are not integrated.
The power generation element of the battery is housed in a battery container, and the integrated circuit chip, which is a memory device, is housed in a memory device container, and each is simply supplied as an independent electronic component.

This is due to the fact that liquid substances are often used as materials for power generation elements in conventional batteries, and because they are highly corrosive materials, semiconductors made of silicon or other compound semiconductor materials Memory element 4
This was because it was extremely difficult to store it in the same container as the intelligent circuit chip.

Purpose of the Invention The present invention integrates an information storage element such as a semiconductor memory element with a battery, and conventionally, when disconnected from the power supply of the device,
The purpose is to change a so-called volatile memory element, which loses all stored information, into a seemingly volatile memory element.

Structure of the Invention The information storage element according to the present invention is made entirely of solid materials and includes a rechargeable secondary battery power generating element within its resin package. By using such a power generating element, the necessary battery capacity can be replenished from an external power source at a timely manner, so the battery capacity can be reduced, and packages for miniaturized element chips such as semiconductor memory elements can be realized. easily fits inside. In addition, since solid materials are used, power generation elements, which are normally known as strong oxidizing or reducing agents or metal corrosive agents, can be packaged in the same package as the memory element chip without having to be confined in a special battery container. Even if it is sealed inside, it will not touch the memory element chip and damage it.

Description of Examples Among the power generation elements of the battery according to the present invention, as the positive electrode active material and the negative electrode active material, for example, CunMX2 (n:0
．． 1-0.8; M: Ti, W, Mo, Nb; X: S, S
o) and CunM003. Cunv205(n:0.
1 to 0.8), and a group of inorganic solid substances represented by Cu 2 S and Cu. In addition, as the electrolyte material, Cu@ion conductive solid electrolyte is used, and CuBr-DTDBr2 (N,N'-dimethyltrimethyldiamine dipromide) system, 7CuBr
・C6H12N4CH3BT or RbCu4 Engineering 2
A Cu" ion conductive solid electrolyte such as the -xC'3+x system can be used. Among these electrolytes, the RbCu I C1 system is particularly suitable for the above-mentioned group of positive electrodes 42-
Even if it is in contact with X 3+x and the negative electrode active material material for a long period of time,
For batteries that are resistant to chemical changes and can be used for long periods of time,
It can be used most suitably.

Table 1 shows some battery systems that use RbCu411.6Ct3.6 as an electrolyte and can be effectively used in the present invention, as well as the battery voltage of a single cell and the combination of positive electrode and negative electrode active materials.

The cell reactions shown in Table 1 are summarized as follows.

The battery reaction of the positive electrode is the battery reaction of the negative electrode.The capacity of the battery is determined by the amount of positive and negative electrode active materials and the δ value. The value of δ should be approximately 0 to maintain good charge/discharge characteristics.
．． It is preferably 1 or less.

A specific example of an information storage element using the power generation element as described above will be described with reference to the drawings.

FIG. 1 is a cross-sectional view of a semiconductor memory element in which a part of the package is a battery container, which is one of the embodiments of the present invention.

1 has a thickness of 0.8 cm, in which the power generation element is made of solid material;
02, which is a 53BX51B unit cell, is a semiconductor memory element chip, and 3 is a lead frame for arranging the semiconductor memory element chip on one side and a group of unit cells on the other side. 4 is an insulating coating layer, and 5 is an electrode for connecting the cells in series. 6 is a resin package that also serves as a battery container.

FIG. 2 is a diagram showing in detail the cross-sectional structure of the cell 1 shown in FIG. 1, where 7 is a positive electrode layer, 8 is a solid electrolyte layer, and 9 is a negative electrode layer. For example, C u o, e which is a positive electrode active material
A positive electrode composition was prepared by mixing V20s powder, Cu(I3 ion conductive solid electrolyte RbCu4I, 5C't3.6 powder, and graphite powder as a conductive agent at a weight ratio of 1:0.05. agent powder 0.08 gr and Cu69 ion conductive solid electrolyte Rb Cu 4I 1.5CZ
3. s powder 0.05g, Cu2S powder, Cu powder, CuΦ ion conductive solid electrolyte RbCu411.5C
13.5 powder in a weight ratio of 1: 4.75: 1.2
Cell pellets with thickness o, sNb, size 5 mm x 58 square, obtained by press-molding 0.15 gr of negative electrode mixture powder mixed at a ratio of 5. Use.

Two such unit cell pellets are joined in series using a conductive adhesive made of carbon powder and epoxy resin to form a battery pack. As shown in Figure 3 1, the thickness is 10~20
On one side of the IJ-deframe 3, an insulating coating 4 made of a polyimide resin coating of μ is coated and baked.
The assembled battery 10 of the set has electrodes 5 made of conductive adhesive,
Glue is placed. FIG. 3 2 shows a front view of the other side of such a lead frame 3, and 2 is a semiconductor memory device chimp, which is a C-MOS static RAM memory device with a memory capacity of 4 kilobytes. .

The power supply voltage when holding memory is approximately 3V.

Power consumption is 0.01 m #-. As shown in FIG. 3, the unit cell group and the semiconductor memory element chip are arranged at predetermined positions on the lead frame and connected by wire bonding, and then the whole is resin packaged by transfer molding. Epoxy resin coated with silica is usually used as a resin material for transfer molding. In addition, heating at 180 to 185°C is required to heat and melt this resin, and Cu n MX 2 is used as a battery power generation element material.
When (X:S) is used, a slight amount of sulfur is generated, so it is preferable to use an acetal resin that can be transferred and molded simply by applying pressure at room temperature.

FIG. 4 shows the battery voltage during charging and discharging at a room temperature of about 20"C for a group of single cells packaged together with a semiconductor memory element in this way. The charging and discharging current values are as follows: 3.
It is 3 μA. Both charging time and discharging time were 300 hours. When the discharge time is about 300 hours, the battery voltage is
The voltage will never drop below 3.0V, which is necessary for memory retention in the semiconductor memory element.

Figure 5 shows the battery voltage at the end of discharge in each cycle of a group of single cells when charging and discharging cycles are repeated with a charging and discharging current value of 3.3 μA and a charging and discharging time of 300 hours; It shows the relationship with the number of charge/discharge cycles. Mitsuru・
Even after 300 discharge cycles, the battery voltage remains at 3.
It shows 0V or more, and the extended discharge time is 9000
This battery can be used for more than 0 hours (approximately 10 years). In fact, the memory retention of the semiconductor memory device using the auxiliary power source is only required when the main power of the device is turned off at night or on holidays, so the semiconductor memory device equipped with the battery according to the present invention is Moreover, it can be made into a semi-permanent nonvolatile memory element in which information can be electrically written and read.

Next, in order to put the information storage element of the present invention into practical use,
In addition to the number of charge/discharge cycles of the power generation element, the degree of deterioration of the battery discharge capacity when the battery is left open-circuited after charging, that is, the magnitude of self-discharge, is a problem. In a solid electrolyte battery, this is largely influenced by the electronic conductivity of the Cu0 ion conductive solid electrolyte layer among the power generation elements. The electrolyte used in this example is one of a series of Cu ion conductive solid electrolytes represented by RbCu4, -xCt3+.
0.5) has particularly low electronic conductivity among these, and the self-discharge of a battery using this during storage is extremely small.

Table 2 shows that among the power generation elements of this example, RbCu4I, −
Using xCi3+, a group of single cells was heated at room temperature of about 20°C.
．． After charging and discharging once for 600 hours at a current value of 3 μA, charging for 300 hours and discharging for 300 hours, charging and discharging for 300 hours at the same current value, and then charging for approximately 20 hours.
The open circuit voltage value when left at 'C for 60 days and the battery voltage when discharged at 3.3 μA after discharge. OVK
This shows the discharge capacity until .

Table 2 RbCu4I, -xC13+, (X=0.25-0.
It can be seen that the electrolyte 6) is extremely superior when the battery is left unused.

In this example, the combination of positive electrode active material and negative electrode active material is positive electrode active material: Cu o, e V2O5.

Although a combination of negative electrode active material: Cu 2 S + Cu was used, no matter which combination of positive electrode active material and negative electrode active material shown in Table 1 is used, the battery voltage will vary from about 3.6V to about 6.6V. It goes without saying that the same effects as in this embodiment can be obtained by configuring the unit cell group so that the voltage is ov.

Effects of the Invention The information storage element of the present invention is one in which an all-solid-state secondary battery-based power generation element is integrally housed in a resin package.
0 that can realize a memory element with built-in auxiliary power supply that is compact and durable for long-term use.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view showing the structure of a semiconductor memory element according to an embodiment of the present invention, FIG. 2 is a cross-sectional view showing the structure of the unit cell in FIG. 1, and FIG. Figure (2
] are a plan view and a back view of the information storage element shown in FIG. 1, FIG. 4 is a graph showing changes in battery voltage during charging and discharging, and FIG. 5 is a graph showing battery voltage at the end of discharge and charging and discharging. It is a graph showing the relationship with the number of discharge cycles. 1...Single cell, 2...Semiconductor memory device chip, 6...Resin package〇Name of agent: Patent attorney Toshio Nakao and 1 other person 1st
Figure 3 (f) 0

Claims (3)

[Claims] (1) A secondary battery-based power generation element made entirely of solid materials is placed inside the resin package housing the information storage element chip, which constitutes an auxiliary power source for the information storage element chip and can be charged externally. Information storage element that is housed and integrated like this (2) Among the power generation elements, the positive electrode and the negative electrode are Cu nM
X2 (n: 0.1-0.8; M: Ti,
W, Mo, Nb;) (:S, Se) and Cun
M003. An inorganic compound represented by Cunv206 (n:o, 1-0.8) and. One or two types selected from the group Cu2S, Cu
The information storage element according to claim 1, characterized in that the information storage element is mainly composed of more than one type of solid substance. (3) Among the power generation elements, the electrolyte is RbCu4, -x
Cu expressed as Ct3+x (x: 0.25-0.5)
■Patent claim F characterized by being an ion conductive solid electrolyte Items 1 and 2