JPH01500785A - integrated circuit - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed description of the invention] integrated circuit This invention relates to integrated circuits.

In recent years, integrated circuits have been leaning toward large-scale integrated circuits.

In these large scale integrated circuits, the performance of individual components within the circuit must be controlled before the circuit is damaged. There is little room to change parameters while in use. Such damage can be caused by e.g. Tracking is achieved by electromigration of conductive tracks. Occurs when a short or open circuit occurs. This damage causes excessive current to flow through the track. And it happens. In addition, even if the cross-sectional area of the track changes slightly, it will take a long time to break the circuit. The time will be significantly reduced. Other parameter changes that may lead to circuit damage Examples are ion diffusion in gate oxides, hot carrier trapping and ionizing radiation. Limit voltage instability due to line effects, for example that of MO8 devices in the circuit.

In systems consisting of many small integrated circuits, these small integrated circuits are easily tested. can be tested and replaced, but this may not be possible in systems consisting of one or more large circuits. It's difficult.

The object of the invention is to provide an integrated circuit that does not have this problem.

According to the present invention, while the operation of the integrated circuit continues to be stopped, the operation of the integrated circuit is stopped. shows the monitor circuit that caused the damage and when this monitor circuit broke. An integrated circuit is provided with means for indicating.

In one particular integrated circuit according to the invention, the monitor circuit includes a conductive pattern and a The current density of the current flowing through the turns is higher than when the integrated circuit is stopped. and means for passing a current through the pattern. Such a monitor circuit is It can be used to monitor damage to integrated circuit conductive parts due to

In such an integrated circuit, the display means indicates when an open circuit occurs in the pattern. Ru. Alternatively, the above-mentioned indicating means may indicate when a short circuit occurs between the pattern and an adjacent conductor. The period may also be displayed.

In another integrated circuit according to the invention, the monitor circuit is a field effect device, which and means for comparing the limiting voltage of the device with a reference voltage. .

Special Table Sen1-500785 (2) Such a monitor circuit monitors changes in the limiting voltage in a field effect device. Can be used for.

In the following, two integrated circuits according to the invention are illustrated with reference to the accompanying drawings, which are for illustrative purposes only. I'll explain.

FIG. 1 is a schematic diagram showing a monitor circuit incorporated in a first integrated circuit; Figure 2 shows the monitor circuit switch. Assembled into the second integrated circuit with the configuration and arrangement of 1 is a schematic diagram illustrating a built-in monitor circuit, and Figure 3 shows the monitor of Figure 2 with the monitor circuit switches arranged in a second configuration. It is a diagram showing a circuit.

First, to explain Figure 1, the monitor circuit built into the first circuit is a power source. to monitor possible damage to metal tracks in integrated circuits due to air migration. It has become. The monitor circuit is connected directly to the resistor 3 placed between the two feed rails 5.7. It consists of a metal test pattern in the form of stripes I connected in columns. this test Patterns are formed on integrated circuits at the same time as other conductive tracks in the circuit, allowing for processing changes. The change in track thickness caused by this change is reflected in the stripe I. monitor times During operation of an integrated circuit incorporating stripe I, the current density of the current flowing through stripe I is Normally, the value is larger than the maximum rating value of the vapor deposition pattern in the integrated circuit. Set the value of resistor 3 to . U-shaped conductive track that partially surrounds stripe l 9 from stripe l by a distance equal to the maximum recommended line spacing in the integrated circuit. Separate. The track 9 is connected by a resistor 11 whose resistance value is somewhat larger than that of the resistor 3. Connect to power supply rail 7.

Stripe I and resistor, each measured with respect to earth, during operation of the integrated circuit Voltage at a point between 3■! Continuously monitor the voltage at a point on the conductive track tar. Since the resistance of the stripe is much larger than the resistance of resistor 3, e.g. Air movement causes an open circuit in stripe I, causing voltage Vl to be close to that of rail 7. The voltage ■l is close to that of the rail 5 until it reaches the rail 5. Usually the warning circuit ( (not shown) are connected to or incorporated into an integrated circuit; When the monitored voltage Vt appears across stripe 1, the voltage Vl issue a warning in response. In addition, this circuit is designed to Provides an early warning when serious damage is likely to occur. Second, high reliability is required. If the integrated circuit Appropriate measures should be taken.

The warning circuit also indicates that stripe 1 is electrically When connected to track 9, it also responds to voltage v2 approaching the voltage value on rail 5. answer.

Note that the test pattern is designed to simulate possible failure modes. It can take the form of

For example, with a step on the underlying polysilicon line or with border contact holes. But that's fine.

Also, the motor now responds to the possible damage of the metal track due to electromobility. The monitor device may be designed to respond only to opens or shorts in the stripe. It may be configured as follows.

Next, to explain FIG. 2, the second integrated circuit is a MOS provided within the integrated circuit. The circuit is configured to monitor critical voltage instability in the transistor. Figure 2 As shown in the figure, monitor transistor 2 is connected between the two power supply rails 23 and 25. Connecting. The gate of this transistor 2I is connected to a two-position switch via a rail 23. 27 movable contacts and fixed contacts, and the drain of the transistor is connected to the via and the other fixed connection of switch 27 to rail 23 through resistor 29. The point connects to a point 30 between the drain and resistor 29. Also, connect in series In addition, two resistors 31 and 33 with the same resistance value are connected between rails 23 and 25. . The fixed contacts of the second three-way switch 35 are connected between the connections of the two resistors 31 and 33. The movable contact is connected to one electrode of the capacitor 37, and the movable contact is connected to one electrode of the capacitor 37, and the movable contact is connected to one electrode of the The other fixed contact is a contact located between the drain of the transistor 21 and the resistor 29. Connect 30J. The second electrode of the capacitor 37 has one n-channel 39 and one connected to the gate electrode of the p-channel 41M0S) transistor, and connected to the gate electrode of the n-channel transistor. The drain of the resistor 39 is connected to the rail 25, and the drain of the n-channel transistor 41 is connected to the rail 25. the source is connected to rail 23, and the remaining sources and drains are connected together. . Further, the second electrode of the capacitor is connected to the solenoid of the transistor 39 via the switch 43. 2 to the conductor connecting the ground and the drain of transistor 4I, as shown in FIG. Close like this. In this regard, Voltage Special Table Hei 1-500785 (3) Monitor v3.

Switches 27, 35 and 43 both consist of synchronized transmission gate circuits. accumulation Approximately 90% of the time when the circuit is operating, the switch is in the position shown in Figure 2. ing. Therefore, the gate of monitor transistor 21 is directly connected to rail 23. to give maximum gate bias.

The output voltage v3 is approximately half the potential difference between the rails 23.25, i.e. V- as shown in FIG. REF, and the capacitor 37 charges up to this voltage. Switch shown in Figure 3 When the switch is turned on, the gate of the monitor transistor 21 is connected to the drain. Then resistor 29b (assuming it has a sufficiently high value, the voltage It settles down around the voltage V・T. Therefore, the switch 35 is placed in the position shown in FIG. When the switch 43 is turned on and the switch 43 is opened, the voltage applied to the capacitor 37 becomes V-T. -V-REF increases. When V-T is greater than V-REF, transistor 4 Only I becomes conductive and the voltage v3 becomes that of rail 25. However, ■・T When V-REF is small, only transistor 39 becomes conductive and the voltage v3 becomes It will be that of Rail 23. In this case, if the limit voltage VT is smaller than V-REF, , a warning circuit (not shown) uses the value of ■3 to issue a warning signal.

Note that the value of V-REF can be easily determined by selecting the values of resistors 31 and 33 relatively. Can be set. It is also generally expected that an integrated circuit according to the invention will have at least four considerations. Incorporating a monitor circuit to monitor the potential voltage instability Changes in maximum and minimum values of p-channel limit voltage and maximum and minimum values of p-channel limit voltage Changes in can be detected.

The above explains how to monitor damage that may be caused by electrical migration or critical voltage changes. The monitor circuit according to the present invention has been described. In the integrated circuit according to the present invention, there are no parameters that may lead to damage to the circuit. Many changes are possible in the data.

international search report m5-+wll@MI A#Ma14 NL PCT/GB 95/QQ547

Claims (5)

[Claims] 1. Damage occurs before the integrated circuit stops operating while the integrated circuit continues to stop operating. This monitor circuit (1, 3, 9, 11) and this monitor circuit (1, 3, 9, 11) means for displaying when the item was damaged. . 2. The monitor circuit (1, 3, 9, 11) detects the current flowing through the conductive pattern (1). Conductive pattern (1) provided so that the current density is higher than when the integrated circuit is not operating An integrated circuit according to claim 1, comprising: 3. Claims wherein the display means displays the time when an open circuit occurs in pattern (1). The integrated circuit according to paragraph 2. 4. When the above display means causes a short circuit between the pattern (1) and the adjacent conductor (9) 3. The integrated circuit according to claim 2, which displays a period. 5. A monitoring circuit electrically applies stress to the field effect device (21). Comparing the limiting voltage of the applying means (30) and the device with a reference voltage (vref) Apparatus according to claim 1, comprising means.