JPS598344A - Semiconductor device - Google Patents

Abstract

PURPOSE:To remove a semiconductor product with a nonstandardized semiconductor substrate positively by making sure a resistivity value of a semiconductor substrate by a breakdown voltage value of a P-N junction. CONSTITUTION:An N<+> type buried layer 4 is formed to the P type semiconductor substrate 5, and N-type epitaxial growth layers 8 are formed onto the layer 4. P type layers 3 for isolating an element are formed to the eptaxial layers 8 so as to be surrounded at distances not joined with the N<+> type buried layer 4 while a P type semiconductor layers 3' is formed in an internal region of the layer 8 so as to join with the upper layer of the N<+> type buried layer 4. An electrode extracting port is formed to the upper surface of the P type semiconductor layer 3', and the layer 3' is wired by a metallic electrode 1. An external metallic wiring terminal A for testing characteristic is formed to the wiring 1. The breakdown voltage of the PN junction between the N<+> type buried layer 4 and the P type semiconductor substrate 5 is measured by applying positive voltage to the electrode section A. The resistivity value (impurity concentration) of the substrate 5 is inspected from the breakdown voltage value.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a semiconductor device, and particularly relates to a
An integrated circuit device (hereinafter referred to as IC) in which an epitaxial growth layer is formed and elements are formed on the surface of the integrated circuit device (hereinafter referred to as IC).
, relates to a semiconductor device having an element for preventing the P-type semiconductor substrate having a specific resistance value different from a desired value from being used and manufactured in a transistor.

Generally, the structure of a bipolar IC is as shown in FIG. A υN type semiconductor layer 8 is formed by epitaxial growth on a semiconductor substrate having an N+ type semiconductor layer formed on the upper surface of the P type semiconductor substrate 5, and a desired element is formed on the upper surface of the N type semiconductor layer. The semiconductor substrate 5 is usually 1 to 20Ω-
A resistor with a specific resistance value of cm is used, but this is selected depending on the circuit and characteristics of the product being manufactured.
A semiconductor with an optimal resistivity value is used.

Although sufficient management is carried out when using these various types of semiconductor substrates, sometimes products with completely different specifications for intended use or products outside the specifications due to manufacturing variations are mixed in. Something happens. In analog ICs etc. that require a relatively high current capacity, the P-type semiconductor substrate has 1 to 1
A material with a specific resistance value of about 0 Ω-cm is used. If this semiconductor substrate contains a substance with a high specific resistance value of 10 Ω-cm or more, the following problems will occur. .

First of all, the I'C of the semiconductor device structure □ in FIG.
In the circuit operation, a current is caused to flow from the element formed on the upper surface of the N-type epitaxial layer 8 to the P-type semiconductor substrate 5, and after passing through the substrate, flows to the element on the N-type epitaxial layer 8. The greater the resistance value, the greater the voltage and voltage drop within the substrate. Generally, the substrate is used as the lowest potential, and the lowest potential is lowered by the voltage drop.

As a result, the potential distribution on the circuit fluctuates and the circuit function malfunctions.1゜The second defect is, for example, when the specific resistance is 5Ω-Cnl and 15Ω.
-cm, the impurity concentration is about one-tenth lower.

When such a substrate is assembled into a case after forming an element, a metal solder is used to alloy and bond the semiconductor substrate and the case, but at this time an N-type layer is formed on the surface of the semiconductor substrate. In such a structure, starting from the P-type semiconductor layer 7 formed in the N-type epitaxial growth layer, the N of one epitaxial growth layer 8, the P of the P-type semiconductor substrate 5, and the N-type layer formed on the bottom surface of the P-type semiconductor substrate. This causes parasitic thyristor characteristics due to the PNPN structure, resulting in serious defects in circuit characteristics.

It would be good if semiconductor devices with defects such as those mentioned above could be completely eliminated as defects through characteristic tests conducted after device formation, but in reality, they vary depending on the conditions under which they are used, and it is difficult to eliminate them only by measuring characteristics. It was extremely difficult to do so, and there was a risk that the product would be shipped outside and cause serious defects. However, in order to prevent the contamination of this type of semiconductor substrate with non-standard products,
Inspecting each board one by one is very expensive and difficult in terms of workability.

SUMMARY OF THE INVENTION An object of the present invention is to provide a semiconductor device in which defects can be reliably removed during characteristic testing in order to prevent the above-mentioned drawbacks.

The present invention is characterized in that a semiconductor layer of a second conductivity type is selectively formed on the upper surface of a semiconductor substrate of a first conductivity type, an epitaxial growth layer of a second conductivity type is formed on the semiconductor substrate, and an epitaxial growth layer of a second conductivity type is formed on the semiconductor substrate of the first conductivity type. An insulating separation layer of a first conductivity type is formed so as to surround the semiconductor layer of a second conductivity type at a distance that does not contact the semiconductor layer, and at the same time, a semiconductor layer of the same first conductivity type as the insulating separation layer is formed between the semiconductor layer of the second conductivity type. Formed so as to be bonded to the upper layer.
A semiconductor device has an outlet provided on the upper surface of the semiconductor layer.

By providing such an element in the substrate, defects can be reliably removed during characteristic testing.

Embodiments of the present invention will be described below with reference to FIGS. 2(a) and 2(b). First, the N-type layer 4 is formed on the P-type semiconductor substrate layer 5 .

Next, each N-type epitaxial growth layer 8 is formed on this upper surface. A P-type semiconductor layer 3 is formed in the epitaxial growth layer 8 so as to surround it at a distance that does not contact the N0-type semiconductor layer 4 for insulation isolation of the elements.

At the same time, a P-type semiconductor layer 3' is formed in the inner region thus surrounded so as to be in contact with the upper layer of the N++ semiconductor layer 4.

A one-pole outlet is provided on the upper surface of the P return conductor layer 3', and a metal electrode 1 is used for wiring. This wiring forms an outer metal wiring terminal A so that a characteristic test can be performed.

The breakdown voltage of the PN junction varies depending on the impurity concentration υ,
Its value is generally known. This invention takes advantage of this point. When a positive voltage is applied to the electrode part A with respect to the P-type semiconductor substrate 5, the P-type semiconductor layer 3' and the N+ type semiconductor rf44 have a forward voltage, and the N++ semiconductor 4 and the P-type semiconductor substrate 5 have a voltage in the opposite direction. voltage. At this time, the breakdown voltage of the PN junction at the reverse voltage is measured. P of insulating separation layer
The junction between the type semiconductor layer 3 and the N type epitaxial growth layer 8 also has a reverse voltage, but the breakdown voltage value of the PN junction becomes lower as the impurity concentration increases. The breakdown voltage value of the junction with the 4P type semiconductor substrate 5 is obtained. The impurity concentration of the N+ type trench conductor layer 4 can be sufficiently controlled as a device characteristic, and the breakdown voltage value corresponding to the impurity concentration of the P type semiconductor substrate 5 can be set. In this way, the specific resistance value (impurity concentration) of the P-type semiconductor substrate 5 can be confirmed by P.
Testing is possible based on the breakdown voltage value of the N+ junction.

By installing the above-mentioned elements, it is possible to conduct characteristic tests at the same time as circuit tests, and semiconductor products with non-standard semiconductor substrates can be removed in advance, which can greatly improve quality and manufacturing. .

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view showing a commonly used semiconductor device.
FIG. 2(a) is a sectional view of a semiconductor device showing an embodiment of the present invention, and FIG. 2(b) is a top view thereof. In the figure, 1...metal electrode, 2...
...Insulating coating, 3.3'...P-type semiconductor layer, 4.
...N''1 semiconductor layer, 5...P type semiconductor substrate, 6...N medium semiconductor layer, 7...
P-type semiconductor layer, 8...N-type epitaxial growth layer, A...metal wiring portion for taking out the electrode to the outside. 1st figure grass 2 figure

Claims (1)

[Claims] A semiconductor layer of a second conductivity type is selectively formed on the upper surface of the semiconductor substrate of the first conductivity type, and a q-epitaxial growth layer of a second conductivity type is formed on the semiconductor substrate and the semiconductor layer of the second conductivity type. , a first conductivity type semiconductor layer is formed as an insulating separation layer in the epitaxial growth layer so as to surround the second conductivity type semiconductor layer at a distance that does not contact the second conductivity type semiconductor layer, and an upper layer of the second conductivity type semiconductor layer is formed in the inner region. 1. A semiconductor device, characterized in that the semiconductor layer is formed so as to be bonded to each other, and an electrode area outlet is provided on the upper surface of the semiconductor layer.