JPS5818781B2 - semiconductor equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a semiconductor device, particularly an integrated circuit chip incorporating a monitor element.

In order to destructively or non-destructively measure the characteristics of the elements that make up an integrated circuit and return the measured data to the manufacturing process and for maintenance and inspection purposes, it is possible to incorporate a monitor element into the chip. It is being done.

For example, if a monitor transistor is manufactured in the same process as the actual transistor, the characteristics of the actual transistor can be estimated by measuring the characteristics of the monitor transistor, and destructive testing is also possible using this method. .

By the way, as is known, in an integrated circuit, the number of pins, that is, the number of external terminals is limited, and it is desirable to avoid having the monitor element exclusively use the pins.

On the other hand, some integrated circuits are provided with a plurality of external terminals of the same potential, such as a small current ground terminal separate from a large current ground terminal.

In such an integrated circuit, after mounting, the plurality of external terminals are short-circuited by wiring, but until then, the terminals are independent from each other.

Therefore, if a monitor element is connected between these terminals,
The characteristics of the monitor element can be checked without using dedicated terminals or pins.

The present invention has been made with attention to this point, and is characterized by the fact that before wiring of a semiconductor chip in which an integrated circuit is constructed, there is substantially insulation, and after wiring, between terminals that are brought to the same potential. ,
A monitor element is formed on the chip and connected thereto to provide a factor to know the characteristics of the integrated circuit.

This will be explained in detail below with reference to the drawings.

In FIG. 1, 10 is a semiconductor chip, and an electronic circuit is constructed by a well-known process.

In this example, this electronic circuit 12 is an operational amplifier and is indicated by its symbol.

14 and 16 are operational amplifier output terminals, and 18 is a power supply terminal.

22, 24, and 26 are resistors that connect the input/output of the amplifier to the ground, and 28 and 32 are ground terminals or bonding pads.

Since the ground terminals 28 and 32 are both grounded, there is no problem in principle if only one of them is used, but if there is a large difference in the current flowing, such as in the input signal circuit and the output stage power supply circuit, If the small current side is affected by the large current side, for example, if you remove the terminal 32 and use the terminal 28 for the ground wiring of the output circuit, the wiring in the integrated circuit is generally made of an aluminum evaporated film and has resistance, so feedback will not occur. I don't like it because it's bad.

Therefore, as shown in the figure, the ground terminal 32 for large current and the ground terminal 28 for small current are separated, and the ground terminal 32 for large current is connected to the conductor stage 20 by an external wiring 34, and the ground terminal 32 for large current is connected to the conductor stage 20 by a wiring 34. A method is adopted in which the wiring 36 leading to the stage 20 and the small current terminal 28 are connected.

If this is done, the electric resistance of the stage 20 is small, so feedback will not be affected. In such an integrated circuit, the chip 10 is of course placed on the stage at the wafer stage, that is, before the chip 10 is scribed. It is not attached and terminals 28 and 32 are insulated.

According to the present invention, two terminals have the same potential after mounting and are substantially the same as one terminal, but are separated before mounting.
A monitor element 30 built into the chip is connected to the terminal using the terminal.

FIG. 2 shows an example of a monitor element, in which a is a pinch resistor and b is a MOS transistor.

The pinch resistor 30a is created together with the bipolar transistor in the impurity diffusion process, and its resistance value serves as a guideline for the hFE of the transistor.

Therefore, during the wafer processing, the hFE of the transistor in the electronic circuit within the chip is estimated by applying a voltage to the terminal 28° 32 and measuring the resistance value, and if there is an abnormality, it is immediately fed back to the manufacturing process. Can be done.

MOS transistor 30b is a monitor element whose gate and source are short-circuited and diode-connected, and which determines the threshold value (vth), which is an important parameter of the MO8I transistor, by knowing the voltage at which current flows between terminals 28 and 32. be.

Of course, this monitor element is also manufactured in the same manufacturing process as the actual operating elements in the chip.

After hFE and Vth are measured by the monitor element, the chip is scribed and mounted on the IC package, and as described in FIG. .

In order to measure the monitor element and estimate the characteristics of the IC element even after mounting, the terminals 28 and 32 may be wired to different pins of the IC package.

In this way, it is possible to remove the IC from the socket or the like and measure the distance between the pins, thereby estimating changes in IC element characteristics over time.

In this case, one extra pin is required, but there are commercially available ICs that have two ground pins, and this can be applied to such ICs.

As the terminals or pins used, in addition to ground terminals, a plurality of terminals such as power supply terminals, which are short-circuited when in use, can be used.

As explained above, according to the present invention, a monitor element can be built into a chip without increasing the number of terminal pins, which is extremely effective.

[Brief explanation of the drawing]

1 and 2 are circuit diagrams showing an embodiment of the present invention. In the drawing, 10 is a semiconductor chip, 28 and 32 are terminals having the same potential, and 30 is a monitor element.

Claims (1)

[Claims] 1. A monitor element that is formed on a semiconductor chip on which an integrated circuit is formed between terminals that are substantially insulated before wiring and that are held at the same potential after wiring, and that provides a factor for knowing the characteristics of the integrated circuit. A semiconductor device characterized by being formed by connecting.