JPH04259234A - Method for measuring semiconductor device - Google Patents

Abstract

PURPOSE:To measure a base-opened collector-emitter withstanding voltage automatically with stability and accuracy, by disconnecting a measurement system from the base of a monitor device designed specifically for measurement of the base-opened collector-emitter withstanding voltage. CONSTITUTION:A measurement system is disconnected from a base terminal of a monitor transistor 1 designed specifically for measurement of the base- opened collector-emitter withstanding voltage VCEO. In this case, the measurement system is connected to as base of a traditional monitor transistor 2 for ordinary characteristic measurement. When the monitor transistor 1 and the traditional monitor transistor 2 are both adequately set on a wafer, then a probe for the traditional monitor transistor in an automatic measurement apparatus can be used, as it is, for the measurement of the base-opened collector- emitter withstanding voltage VCEO with stability and accuracy.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of manufacturing a semiconductor device, and more particularly to a method of measuring a monitor element in the manufacture of bipolar devices.

Process reproducibility is required to improve the performance of recent semiconductor devices. However, at present, there is not enough margin for variations in device characteristics between wafers due to process fluctuations, etc., and therefore there is a demand for automatic measurement and evaluation of all monitor elements provided on all wafers.

Bipolar devices are similarly provided with monitor elements on all wafers, but the measurement of the collector/emitter breakdown voltage (VCEO) with an open base is not accurate due to the capacitance and leakage current of the measurement system connected to the base. I couldn't do it.

The present invention can be used as a method for stably measuring the accurate value of the collector-emitter breakdown voltage VCEO with an open base.

[0005]

2. Description of the Related Art The collector-emitter breakdown voltage VCEO of a bipolar transistor with an open base is defined as the maximum rating of the transistor as the most severe condition for the collector-emitter breakdown voltage.

As is well known, when the base-emitter resistance RBE is changed from 0 to ∞, the collector-emitter breakdown voltage VCER gradually decreases and reaches a minimum when RBE=∞. The value at this time becomes VCEO.

[0007] Conventionally, VCEO was measured by placing probes on the emitter, base, and collector terminals of the monitor element, and disconnecting the base/emitter in the measuring instrument.

In this case, as mentioned above, accurate values cannot be obtained due to the capacitance, leakage current, etc. of the measurement system connected to the base, so give up on automatic measurement and perform manual measurement by removing the base wiring of the measurement system. was measuring.

[0009]

[Problems to be Solved by the Invention] In the conventional example, automatic measurement of monitor elements is not possible, and manual measurement increases man-hours. A problem has arisen in that processing is required.

[0010] Here, the data processing performed in order to treat data obtained by manual measurement in the same manner as other data obtained by automatic measurement refers to statistical processing (average value, standard deviation, trend, When displaying graphs (correlation, etc.), VCEO means that corrections must be input into the computer based on manually measured data.

The object of the present invention is to provide a method that can automatically measure the collector-emitter breakdown voltage VCEO with an open base, and can do so stably and accurately.

0012

[Means for solving the problem] The solution to the above problem is 1)
Using a monitor element formed on the surface of a semiconductor substrate and consisting of a bipolar transistor that has a collector measurement terminal connected to a collector electrode and an emitter measurement terminal connected to an emitter electrode, but does not have a base measurement terminal connected to a base electrode, the collector A method for measuring a semiconductor device, comprising the step of connecting a measuring terminal and the emitter measuring terminal to a measuring instrument and measuring the collector/emitter withstand voltage VCEO with an open base, or 2) measuring a monitor element for measuring characteristics. Using the collector probe, base probe, and emitter probe used in
This is achieved by the method for measuring a semiconductor device described in 1) above, which measures EO.

[0013]

[Operation] Since the measurement system of the present invention is not connected to the base of the monitor element dedicated to measuring the collector-emitter withstand voltage (VCEO) with the base open, the effects of the capacitance and leakage current of the measurement system are removed, allowing accurate automatic measurement. It is designed to be measurable.

[0014]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a plan view illustrating an embodiment of the present invention. In the figure, (1) is a monitor transistor dedicated to VCEO measurement, and the base is not wired to connect to the measurement system.

[0015] (2) is a conventional monitor transistor for normal characteristic measurement, and the base is wired to connect to the measurement system. The symbols in the figure represent the following, and the numbers 1 and 2 in the symbols are (1) and (2) of the monitor transistors mentioned above.
) corresponds to

C1, C2 are collector electrodes, E1,
E2 is the emitter electrode, B1 and B2 are the base electrodes,
C1P and C2P are collector measurement pads, EP is a common emitter measurement pad, and B2P is a base measurement pad.

If a monitor transistor (1) dedicated to VCEO measurement is formed at an appropriate position on the wafer together with a conventional monitor transistor (2), the probe used for measuring the conventional monitor transistor of an automatic measuring device can be used as is. VCEO can be measured accurately and stably.

When measuring a certain manufacturing lot to see the effect of the embodiment, it was found that in the conventional example, VCEO = 0 to 25
According to the example, the variation with VC was
EO was within the range of 5 to 8 V. This indicates that in the conventional example, an apparent value was measured.

[0019]

[Effects of the Invention] It has become possible to stably and accurately automatically measure the collector/emitter breakdown voltage VCEO with an open base.

As a result, the conventional manual measurement and data processing thereof can be omitted, contributing to a reduction in man-hours.

[Brief explanation of the drawing]

[Fig. 1] Plan view explaining one embodiment of the present invention

[Explanation of symbols]

C1, C2 Collector electrode E1, E2 Emitter electrode B1, B2 Base electrode

Claims (2)

[Claims] [Claim 1] A monitor element formed on the surface of a semiconductor substrate and consisting of a bipolar transistor that has a collector measurement terminal connected to a collector electrode and an emitter measurement terminal connected to an emitter electrode, but does not have a base measurement terminal connected to a base electrode. 1. A method for measuring a semiconductor device, comprising the step of: connecting the collector measurement terminal and the emitter measurement terminal to a measuring device to measure a collector-emitter breakdown voltage VCEO with an open base. 2. Using a collector probe, a base probe, and an emitter probe used for measuring the monitor element for characteristic measurement, the collector probe and the emitter probe of these probes are brought into contact with the collector measurement terminal and the emitter measurement terminal, respectively. 2. The method for measuring a semiconductor device according to claim 1, wherein VCEO is measured using the following steps.