JPH0447975B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a semiconductor device, and particularly to a semiconductor device including a semiconductor element for measuring characteristics.

In recent semiconductor integrated circuits, high integration,
The miniaturization of elements is progressing rapidly due to advances in various processing techniques, and semiconductor elements, wiring, etc. are becoming smaller, and the chip area for the same circuit size is decreasing year by year. However, on the other hand, although the semiconductor elements built into integrated circuits for measuring characteristics have become smaller, the metal pads used to bring the probe into contact with them from the outside during measurement have become smaller. Considering the ease of needle alignment,
It cannot be made into a small area. Further, this semiconductor element for measuring characteristics needs to be placed at a certain distance from other elements and wiring so as not to damage other elements and wiring during probe contact work. In addition to this, for example, in the case of MOSFET,
As circuits are configured to use more threshold voltages, the number of MOSFET patterns to be measured is increasing.

FIGS. 1a to 1c are a plan view, a circuit symbol diagram, and a sectional view of a conventional MOSFET for measuring characteristics when a measuring probe is brought into contact with a metal pad. Note that the oxide film is omitted in FIG. 1a to clearly show the structure.

As shown in FIGS. 1a-c, a semiconductor substrate 10
Source region 1 and drain region 2 formed on
are connected to metal pads A and B through openings 3 in oxide film 5. Similarly, the polysilicon layer forming the gate electrode 4 is connected to the metal pad C through the opening 3. Since the metal pad makes contact with the measurement probe 6, the area cannot be smaller than a certain level, and therefore the metal pad occupies most of the area of the MOSFET.

Therefore, when a circuit with many threshold voltages is designed, the measurement MOSFETs for those types are formed on the same chip.
The disadvantage is that the proportion occupied by the area becomes large and the proportion of the effective element forming area becomes small.

The purpose of the present invention is to eliminate the above-mentioned drawbacks and to
The object of the present invention is to provide a semiconductor device with an improved degree of integration by reducing the area of a MOSFET and increasing the ratio of an effective element formation area.

In the semiconductor device according to the present invention, the characteristic measuring semiconductor elements provided in the device are first and second semiconductor elements, respectively.
and a gate electrode formed between these regions with a gate insulating film interposed therebetween.
The MOSFETs are arranged on the same straight line, and the second
The MOSFET is arranged between the first MOSFET and the third MOSFET on another straight line parallel to the straight line, and the gate electrode of the second MOSFET extends in a direction perpendicular to the straight line. The gate electrodes of the first and third MOSFETs are connected to a first conductive pad that connects the first regions of the first and third MOSFETs, and the gate electrodes of the first and third MOSFETs extend in a direction perpendicular to the straight line. a second and a third connected to the first and second regions of the MOSFET, respectively;
The present invention is characterized in that fourth and fifth conductive pads are provided, each connected to the second region of the first and third MOSFETs.

Next, embodiments of the present invention will be described in detail using the drawings.

FIGS. 2a and 2b are a plan view and a circuit symbol diagram of an embodiment of the present invention. In FIG. 2a, the oxide film is omitted as in the case of FIG. 1a.

As shown in FIGS. 2a and 2b, three measurement MOSFETs Tr1, Tr2, and Tr having a source region 1, a drain region 2, and a gate electrode 4 are mounted on the semiconductor substrate.
3 are formed, and each terminal is connected to five metal pads A to E. In particular, the metal pad C has the drain electrode of the first MOSFET: Tr1,
Second MOSFET: Tr2 gate electrode and third MOSFET
MOSFET: The source electrode of Tr3 is connected.
In the three measurement MOSFETs formed in this way, the proportion occupied by metal pads is 5/9 compared to the conventional one. If there are more MOSFETs for measurement, this value will approach 1/3 because the number of metal pads connected to the three electrodes will increase.
In other words, the ratio occupied by the measurement MOSFET is nearly 1/3 that of the conventional case, and the ratio of the effective element formation area increases accordingly.

Next, we will explain how to measure the characteristics of these MOSFETs.

FIGS. 3a to 3c are circuit symbol diagrams for explaining the characteristic measuring method of the embodiment of the present invention shown in FIGS. 2a and 2b.

First, as shown in Figure 3a, when measuring the characteristics of Tr1, short-circuit metal pads D and E,
Ground potential V _E is applied to metal pads A, B, and C, respectively.
The static characteristics of Tr1 are measured by bringing three measurement probes into contact so as to give a gate potential V _A and a drain potential V _B. In this case, Tr2 and Tr3 have no influence.

Next, when measuring Tr2, rotate the semiconductor substrate at 180°.
The metal pads E and A rotate as shown in Figure 3b.
short-circuit and connect metal pads B, C, and D to V _B , respectively.
Measure the static characteristics by touching the measurement probe so that V _A and V _E. In this case, Tr1 and Tr3 are Tr
It does not affect the measurement of 2.

When measuring Tr3, as shown in Figure 3c, metal pads C, D, and E are used as in the case of Tr1.
The static characteristics are measured by touching the measuring probe so that V _E , V _A and V _B are applied. In this case as well, Tr1 and
Tr2 does not affect the measurement.

Metal pads A, B, C, D, E shown in Figure 2a
A triangle with the same size and the center of each metal pad as its apex, for example, metal pads ABC, BCD,
If the triangle formed by the vertices of the CDE is formed as an equilateral triangle, there is no need to change the mutual positions of the probes in contact with the metal pad.
MOSFET characteristics can be measured with ease.

As explained in detail above, according to the present invention,
By commonly using the metal pads of the MOSFETs for measurement so as not to affect the characteristic measurements, the number of metal pads can be reduced and a semiconductor device with a larger proportion of the effective element formation area can be obtained, which is highly effective.

[Brief explanation of the drawing]

Figures 1 a to c are a plan view, a circuit symbol diagram, and a sectional view of a conventional MOSFET for measuring characteristics, and a cross-sectional view when a measuring probe is brought into contact with a metal pad, and Figures 2 a and b are an embodiment of the present invention. Plan view and circuit symbol diagram, Figure 3a
-c are circuit symbol diagrams for explaining characteristic measurement of an embodiment of the present invention shown in FIGS. 2a and 2b. 1... Source region, 2... Drain region, 3...
...Opening portion, 4...Gate electrode, 5...Oxide film, 6
...Tip, 10...Semiconductor substrate, Tr1...1st
MOSFET, Tr2...Second MOSFET, Tr3
...Third MOSFET, A, B, C, D, E...
Metal pad.

Claims (1)

[Scope of Claims] 1. In a semiconductor device including a semiconductor element for characteristic measurement, each of the semiconductor elements for characteristic measurement has a first region and a second region, and a gate electrode formed between these regions with a gate insulating film interposed therebetween. , the first and third MOSFETs are arranged on the same straight line, and the second MOSFET is arranged on the same straight line parallel to the straight line. The gate electrode of the second MOSFET extends in a direction perpendicular to the straight line and connects the first regions of the first and third MOSFETs. The gate electrodes of the first and third MOSFETs extend in a direction perpendicular to the straight line and connect to the second MOSFET.
second and third conductive pads respectively connected to the first and second regions of the MOSFET, and fourth and third conductive pads respectively connected to the second regions of the first and third MOSFETs. 1. A semiconductor device comprising: 5 conductive pads. 2. A triangle having apexes at the centers of the first, second and third conductive pads, a triangle having apexes at the centers of the first, second and fourth conductive pads, and a triangle having apexes at the centers of the first, second and fourth conductive pads; 2. The semiconductor device according to claim 1, wherein the first to fifth conductive pads are formed such that each triangle having an apex at the center of the fifth conductive pad is an equilateral triangle.