JPH0287542A - Inspection device - Google Patents

Abstract

PURPOSE:To make it feasible to observe the electric signals inside an element to be inspected non-destructively and noncontactly by a method wherein the element is scanned on a focus point of a magnetic lens so that the electric signals and the channel status thereof may be observed three-dimensionally. CONSTITUTION:A specimen base 2 is properly shifted so that the part of an element to be inspected may be scanned relatively on the focus point of a magnetic lens 4. The analog current levels detected by respective superconductive detecting elements 41a-43a are binary-coded through an A/D converter 5 to be inputted to a signal processor 6. The signal processor 6 performs the specified analysis based on the scanning positions to be changed by the shifting specimen base 2 as well as the distribution status of the detected magnetic induction flux density conforming to the previously set up program so that the potentials and the variable currents in the wiring structure inside the element 3 to be inspected may be detected three-demensionally to be inputted to an output device 7 for the display as visible picture images. Through these procedures, the electric signals inside the element 3 to be inspected can be observed non- destructively and noncontactly.

Description

[Detailed Description of the Invention] [Prior Art] The present invention relates to inspection technology, and is particularly applicable to non-contact and non-destructive observation of electrical signals such as current and voltage inside semiconductor integrated circuit devices. Concerning effective techniques.

[Conventional technology]

For example, as a technology for non-contact measurement of electrical signals in the internal wiring structure of a semiconductor integrated circuit device, for example, Ohmsha Co., Ltd., published on November 30, 1980, Tachibana, Institute of Electronics and Communication Engineers, "LSI Handbook" JP6
As described in 65 to 666, an EB test device is known that utilizes the fact that the amount of secondary electrons generated from a site irradiated with an electron beam depends on the potential at the irradiation site.

In other words, by irradiating an electron beam with the target wiring structure exposed and observing an image whose brightness is modulated by the intensity of secondary electrons generated from the irradiated area, the potential distribution of the target wiring structure can be determined. It is observed as a dimensional image.

[Problem to be solved by the invention]

However, in the above-mentioned conventional technology, it is necessary to expose the target observation site to the electron beam (because it is necessary to expose the target observation site to the electron beam, for example, it is made of ceramics? There is a problem in that it is practically difficult to observe the lower layer of a multilayer wiring structure in a multilayer wiring board or a semiconductor integrated circuit device.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide an inspection technique that allows observation of electrical signals inside an object to be inspected in a non-contact and non-destructive manner.

The above and other objects and novel features of the present invention will become apparent from the description herein and the accompanying drawings.

[Means to solve the problem]

A brief overview of typical inventions disclosed in this application is as follows.

That is, the inspection device according to the present invention includes a plurality of superconducting magnetic sensing elements concentrically arranged on a substrate and an electronic circuit that holds sampling outputs of the superconducting magnetic sensing elements, and a test device located at a focal point. A magnetic lens that detects magnetic changes in an object, an analog-to-digital converter that converts the sampling output output as an analog signal from the magnetic lens into a digital signal, a signal processing means that analyzes the digital signal, and a digital signal converter. The device is equipped with an output means for visualizing and outputting the analysis results, and by scanning the focus on the object to be measured, it is possible to three-dimensionally observe the state of the electrical signal and the path of the electrical signal inside the object to be measured. This is how it was done.

[Effect]

According to the above-described inspection technology of the present invention, observation is performed using magnetism generated as a result of changes in potential and current over time in the current path inside the object to be inspected, so that the object to be inspected is observed. If the area is magnetically blocked by a transparent material, there is no need to destroy a part of the object to be inspected, for example to expose the target observation area to the outside, and It is possible to observe electrical signals and electrical signal paths inside the device in a non-contact and non-destructive manner.

〔Example〕

FIG. 1 is a block diagram showing the main parts of an inspection apparatus according to an embodiment of the present invention, and FIG. 2 is an explanatory diagram showing the negative part in more detail.

Magnetic shield room that blocks external magnetic noise
A sample stage 2 is provided inside the sample stage 2, which can be moved freely in a horizontal plane and vertically.For example, a semiconductor integrated circuit device or a semiconductor integrated circuit device is mounted on this sample stage 2. It is configured such that an object to be inspected 3 such as a multilayer wiring board is placed thereon in a detachable manner.

This sample stage 2 is provided with a socket (not shown) depending on the type of the object to be measured 3, etc., and it is possible to put the object to be measured 3, such as a semiconductor integrated circuit device, into a normal operating state. ing.

A magnetic lens 4 is provided above the sample stage 2 and is configured to detect weak magnetism generated from inside the object to be inspected 3 with high sensitivity.

That is, this magnetic lens 4 is, for example, as shown in FIG.
Using J-thography technology, etc., a plurality of superconducting magnetic sensing elements 41a, 42a, 43a made of superconducting materials are arranged on a circumference with different radii, and the plurality of superconducting magnetic sensing elements 41a to 43a are arranged in concentric circles. It is constructed by overlapping substrates 41 to 43 such that

The propagation time of the magnetic signal from the focal position of the magnetic lens 4 to the individual superconducting magnetic sensing elements 4ia, 42a, and 43a is made equal.

Although not particularly shown, individual substrates 41, 42, 43
A plurality of superconducting magnetic sensing elements 41a, 42a arranged in
, 43a is equipped with an electronic circuit that functions to sample the current generated when the magnetic flux crosses the superconducting magnetic sensing element at a predetermined time interval and hold it as an analog quantity using well-known photolithography technology. It is formed.

In addition, these electronic circuits have an A that binarizes the analog measurement signal sampled in the electronic circuit.
/D converter 5 is connected, and this A/D converter 5 is also connected.
A signal processing device 6 consisting of, for example, a microprocessor is connected to the converter 5.

This signal processing device 6 analyzes the temporal changes in a plurality of measurement information corresponding to the plurality of superconducting magnetic sensing elements 41a, 42a, and 43a constituting the magnetic lens 4. The current and potential in the internal wiring structure of the object to be measured 3 located at the focal point of the object 3 are measured.

Further, an output device 7 consisting of, for example, a cathode ray tube or a printer is connected to the signal processing device 6, and a three-dimensional image such as a current path inside the object to be measured 3 obtained by the signal processing device 6 is displayed. configured to be displayed.

The operation of this embodiment will be explained below.

First, the object 3 to be measured, such as a semiconductor integrated circuit device or a multilayer wiring board on which the semiconductor integrated circuit device is mounted, is set on the sample stage 2 at the focus position of the magnetic lens 4 in its normal state.

Thereafter, the object to be measured 3 is brought into a normal operating state so that an electrical signal flows through the internal wiring structure (not shown), and the sample stage 2 is moved appropriately so that the focus position of the magnetic lens 4 is adjusted. A target inspection region of the object 3 to be inspected is relatively scanned.

At this time, a part of the magnetic flux generated by the electric signal flowing inside the object to be inspected 3 crosses the magnetic lens 4, and the plurality of superconducting magnetic sensing elements 41a, 4 forming the magnetic lens 4
A current is generated in 2a, 43a by this magnetic flux, and an electronic circuit (not shown) connected to the superconducting magnetic sensing elements 41a, 42a, 43a detects and holds this current as an analog l by sampling operation at a predetermined period. do.

In this embodiment, a plurality of superconducting magnetic sensing elements 41a, 42
Detection sensitivity is increased by synchronizing the sampling period and timing of each of a and 43a.

Then, the individual superconducting magnetic sensing elements 41a, 42a, 4
The current value of the analog quantity detected in each of 3a is
After being binarized through the A/D converter 5, it is manually input to the signal processing device 6.

The signal processing device 6 uses a preset program to determine a predetermined value based on the scanning position caused by the displacement of the sample stage 2 and the distribution state of the strength and weakness of the magnetic flux detected in the individual superconducting magnetic sensing elements 41a, 42a, and 43a. The analysis operation is performed to three-dimensionally understand the changes in potential and current in the target wiring structure (not shown) inside the object to be inspected 3, and send it to the output device 7, and display it as a visible image on the output device 7. .

The operator then uses the image displayed on the output device 7 to observe the presence or absence of electricity and changes in potential in the wiring structure inside the object 3 to be inspected. The presence or absence of wire breakage in the structure and the operating state of the object to be inspected 3 are checked.

In this way, according to this embodiment, the state of the electric signal in the wiring structure inside the object to be inspected 3 can be known through the magnetism generated from the object to be inspected 3.
Electric signals inside the object to be inspected 3 can be observed in a non-contact and non-destructive manner without breaking a part of the object to be inspected 3 to expose the intended wiring structure.

Furthermore, it is not necessary to perform complicated work such as breaking a part of the object 3 to be inspected prior to the inspection, and the time required for the inspection is shortened.

Furthermore, since the inspection can be performed without destroying the inspected object 3, the inspection apparatus of this embodiment is incorporated into a part of the manufacturing process of the inspected object 3 such as a semiconductor integrated circuit device, so-called in-line inspection. This makes it possible to improve productivity in the manufacturing process of semiconductor integrated circuit devices and the like.

Although the invention made by the present inventor has been specifically explained above based on Examples, it goes without saying that the present invention is not limited to the Examples and can be modified in various ways without departing from the gist thereof. Nor.

For example, in the above embodiment, the magnetic lens is placed only on one side of the object to be inspected, but the invention is not limited to this, and a plurality of magnetic lenses may be placed at positions surrounding the object to be inspected. .

〔Effect of the invention〕

Among the inventions disclosed in this application, the effects obtained by typical ones are briefly explained below.

That is, the inspection apparatus of the present invention includes a plurality of superconducting magnetic sensing elements concentrically arranged on a substrate and an electronic circuit that holds sampling outputs of the superconducting magnetic sensing elements, and the inspection apparatus is configured to detect an object to be measured located at a focal point. a magnetic lens for detecting a magnetic change in the magnetic lens; an analog-to-digital conversion means for converting the sampling output output as an analog signal from the magnetic lens into a digital signal; a signal processing means for analyzing the digital signal; It consists of an output means that visualizes and outputs the signal analysis results,
By scanning the focal point with respect to the object to be measured,
Since the state of the electrical signal and the path of the electrical signal inside the object to be measured is observed three-dimensionally, if the target observation area of the object to be inspected is hidden by a magnetically transparent material, For example, there is no need to destroy a part of the object to be inspected in order to expose the target observation area to the outside.
Electrical signals and electrical signal paths inside the object to be inspected can be observed in a non-contact and non-destructive manner.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing the main parts of an inspection device that is an embodiment of the present invention, and FIG. 2 is an explanatory diagram showing a part thereof in more detail. DESCRIPTION OF SYMBOLS 1... Magnetic shield room, 2... Sample stage, 3... Test object, 4... Magnetic lens, 41-43... Substrate,
41a to 43a... superconducting magnetic sensing element, 5...A
/D controller part, 6...signal processing device, 7...output device. Agent: Patent Attorney Katsuo Ogawa, - 2nd 41-43: Substrates 41a-43a: Superconducting magnetic sensing element

Claims (1)

[Claims] 1. An object to be measured located at a focal point, consisting of a plurality of superconducting magnetic sensing elements arranged concentrically on a substrate and an electronic circuit that holds sampling outputs of the superconducting magnetic sensing elements. a magnetic lens for detecting magnetic changes; an analog-to-digital conversion means for converting the sampling output output from the magnetic lens as an analog signal into a digital signal; a signal processing means for analyzing the digital signal; and a signal processing means for analyzing the digital signal. and an output means for visualizing and outputting the analysis results of the object to be measured, and by scanning the focal point with respect to the object to be measured, the state of the electric signal inside the object to be measured and the path of the electric signal can be visualized in three dimensions. 1. An inspection device characterized in that it is designed to perform a specific observation. 2. Claim 1, characterized in that temporal changes in the electrical signal observed at the focal position of the object to be measured are observed.
Inspection equipment as described. 3. The inspection apparatus according to claim 1 or 2, wherein the object to be measured is a semiconductor integrated circuit device, and the electrical signal inside the semiconductor integrated circuit device is observed in a non-contact and non-destructive manner.