JPS61276337A - Semiconductor inspecting device - Google Patents

Abstract

PURPOSE:To inspect without characteristic deterioration nor damage by mounting a light signal conductor on a supporting substrate, and applying a light signal from its output terminal to the arbitrary position on the surface of an LSI. CONSTITUTION:An optical fiber 2 is mounted on an independently movable base 1 in elevational, longitudinal and lateral directions, one end 3 is connected through a connector 4 with a laser light source 5, and a condensing lens 7 is mounted at the other terminal 6. A voltage source 9, an input signal source 10, and an output signal measuring instrument 11 are connected with an LSI 8. When a light is emitted to a semiconductor, electron-hole pairs are excited therein. Accordingly, a signal is input to the LSI interior by controlling the type, emitting light amount, emitting time and place of a light source to effectively evaluate the characteristics and to analyze a defect in combination with the conventional electric inspecting method.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to an inspection device used for characteristic inspection and failure analysis of semiconductor devices such as LSIs (semiconductor integrated circuits). The present invention provides a semiconductor inspection device equipped with an input means.

Conventional technology: Inspection of electrical characteristics and failure analysis of LSI involves inputting an electrical signal to the signal input terminal of the LSI, observing the electrical signal obtained from the output terminal, and determining whether or not the LSI is good or evaluating its characteristics. Ta. However, as LSIs become smaller and more highly integrated, it has become difficult to perform sufficient characteristic evaluation and failure analysis using only the method using input and output terminals as described above. It is necessary to input signals and directly observe the electrical status of internal circuits.

Conventionally, AI inside LSI was used for such purpose! Electrical signals were input or observed by bringing a metal probe into contact with the wiring pattern. However, this method
With the miniaturization and higher density of I, it has become difficult to bring the metal probe into precise contact with the Al wiring pattern inside the LSI, making it no longer compatible with today's LSIs.

In recent years, in response to the above problem, E-B (Eleat ran-
Beam) tester has been developed. This device irradiates the LSI surface placed in a vacuum sample chamber with an electron beam (EB) accelerated with an accelerating voltage of several kilovolts, detects the secondary electron signal emitted from the LSI surface, and then detects the secondary electron signal emitted from the LSI surface. It is used to observe the physical state of the device, and has the feature of being able to cope with the miniaturization and high density of LSIs.

On the other hand, by scanning the LSI surface with a single laser beam,
A method has been proposed for analyzing the internal operating state of an LSI by detecting an internally generated photoexcitation current from a power supply terminal of the LSI. (Nagase: "Laser scanning device analysis system" IEICE, Semiconductor Transistor Study Group material, 5SD Problems to be solved by the invention The conventional devices and methods described above can detect the electrical operating state of the internal circuit of an LSI without contact. It is intended for analysis and does not have the function of applying signals to the internal circuits of the LSI.

For this reason, if a fault exists in a certain circuit block of an LSI made up of a plurality of circuit blocks, it is not possible to analyze the characteristics of the faulty circuit and subsequent circuits.

Further, there are problems such as the inability to evaluate the characteristics of each functional block or circuit that constitutes an LSI.

In addition, the above-mentioned EB tester also increases the acceleration energy and
By adjusting the irradiation method of B, in principle, LSI
It becomes possible to apply signals internally. However, in this case, the LSI surface is irradiated with a high-acceleration-energy electron beam, resulting in deterioration or destruction of the LSI characteristics.
Not practical.

Furthermore, even with the conventional method of scanning the LSI surface with a laser beam, it is theoretically possible to apply a signal inside the LSI by appropriately selecting the laser power and laser irradiation location. However, since this method uses a single laser beam, it is not possible to input signals to multiple locations at the same time. In addition, implementing this method requires large-scale equipment;
It ends up being expensive. Furthermore, since this method narrows down the laser beam, it is only possible to apply a signal within the field of view determined by the objective lens of an optical microscope, making it inapplicable for analysis of large-diameter LSIs.

Means for Solving the Problems The present invention has been made in view of the above problems, and includes an optical signal conductor in which one end of the support base is used as an optical signal input terminal and the other end is used as an optical signal output terminal. The optical signal output from the optical signal output terminal of this optical signal conductor is connected to the LSI.
By irradiating a desired part of the surface, it is possible to apply a signal to any location inside the LSI.

By using the above-mentioned means, the present invention makes it possible to simultaneously apply signals to multiple locations even in a large-diameter LSI without causing characteristic deterioration or destruction of the LSI. (Depending on the configuration), it is possible to realize a semiconductor inspection device at low cost.

Embodiment An embodiment of a semiconductor inspection apparatus according to the present invention will be described with reference to the configuration diagram shown in FIG.

In FIG. 1, the support base is constituted by a stage 1 that can be independently moved up and down, right and left, and one back and forth direction, and one optical fiber 2 is attached to the stage 1. Here, one end 3 of the optical fiber 2 is an optical signal input terminal, and a semiconductor laser, He-
It is connected to a light source 6 such as a Ne laser. The other end 6 is a light output terminal, and a condenser lens 7 is attached to the light end. Here, the optical fiber 2 is bent and fixed to the unheld base 1 as necessary so that its light output is output in a predetermined direction.

Next, the semiconductor inspection apparatus according to this embodiment will be explained using FIG. 2. In Figure 2, the power supply terminal of LSI8,
The input terminal and the output terminal each have a voltage source 91. Input signal source 10. An output signal measuring device 11 is connected. Now, L
It is necessary to directly apply a signal to the inside of the SI, and the semiconductor inspection device of this embodiment irradiates the surface of the LSI 8 with light.Here, the stage 1 can move up and down, right and left, and in the front and rear directions. It becomes possible to irradiate light to any location. Furthermore, a condensing lens 7 attached to the optical output terminal of the optical fiber 2 irradiates the LSI with finely focused light. Note that if there is no need to narrow down the irradiated light, the condenser lens 7 is not necessarily necessary.

Generally, when a semiconductor is irradiated with light, electron-hole pairs are excited inside the semiconductor. For this reason, by controlling the type of light source, the amount of light irradiated, the irradiation time, and the location where it is irradiated.
l) Signals can be input into the LSI.

As described above, the semiconductor inspection apparatus of this embodiment enables light irradiation to any location on the surface of an LSI, and when combined with the conventional electrical inspection method, more effective characteristic evaluation and Failure analysis becomes possible.

Next, an embodiment of the semiconductor inspection apparatus according to the present invention in which a plurality of photoconductors are provided on one support base will be described with reference to FIG. In FIG. 3, a plurality of optical fibers 23 are attached to a glass-epoxy substrate 22 having a cavity 21. As shown in FIG. A collective lens 24 is attached to the optical output terminal of each optical fiber, and the optical input terminal is connected to a light source, respectively. In this embodiment, the light irradiation part of the LSI is determined in advance, and the support base is placed with the optical fiber's optical output terminal or the condensing lens aligned so that the light is irradiated to the determined location. needs to be fixed. According to this embodiment, it is possible to irradiate light onto a plurality of predetermined locations by aligning the LSI once, and more complex characteristic evaluation and failure analysis are possible.

In the embodiment shown below, a plurality of optical fibers and metal probes are provided on one support base.

As shown in FIG. 4, a plurality of optical fibers 32 and metal probes 33 are attached to the support base 31. As in the above embodiment, a condenser lens 3 is provided at the tip of the optical fiber 32.
4 are provided. According to the semiconductor testing device of this embodiment, it is possible to perform characteristic evaluation and failure analysis by combining electrical analysis and analysis using optical signal input. For example, LSI power supply, G
By contacting the ND terminal and the output terminal with a metal probe, it becomes possible to provide an input signal with light. In addition, the conventional example will be used to explain 9E.
If used in combination with the -B tester, it is possible to contact only the power supply and GND terminals with a metal probe, give the input signal with light, and detect the output with secondary electrons.

In this embodiment, the optical signal conductor is constructed of an optical fiber, but any material may be used as long as it can efficiently transmit light.

Effects of the Invention The semiconductor inspection device of the present invention enables inspection of large diameters (ll, T, S
It is also possible to apply signals to multiple locations at the same time, making it possible to perform characteristic evaluation and failure analysis for each functional block or circuit block of an LSI, which was previously impossible, at low cost.

[Brief explanation of drawings]

FIG. 1 is a schematic perspective view of a semiconductor inspection device according to an embodiment of the present invention, FIG. 2 is a perspective view of an application example of the semiconductor inspection device of the present invention,
FIG. 3 is a perspective view of essential parts of a device according to another embodiment of the present invention;
The figure is a perspective view of essential parts of a device according to still another embodiment of the present invention. 1... Stage, 2... Optical fiber, 7... Condensing lens, 8... LSI,
22...Glass-epoxy substrate, 23...
...Optical fiber, 24...Condensing lens, 32
・・・・・・Optical fiber, 34・River・Condensing lens,
33...Metal probe. Name of agent: Patent attorney Toshio Nakao and 1 other person No. 1
Figure S Figure 3 Figure 4

Claims (6)

[Claims] (1) An optical signal conductor having one end as an optical signal input terminal and the other end as an optical signal output terminal is installed on a supporting base, and the optical signal output from the optical output terminal is transmitted to the surface of the semiconductor device. A semiconductor inspection device characterized in that it irradiates a desired part of a semiconductor device. (2) The semiconductor inspection apparatus according to claim 1, wherein the supporting base is constituted by a stage that can be independently moved in the vertical, horizontal, and front-back directions. (3) The semiconductor inspection device according to claim 1, wherein the supporting base is composed of a flat substrate. (4) The semiconductor inspection device according to claim 1, wherein the photoconductor is made of an optical fiber. (5) The semiconductor inspection device according to claim 1, characterized in that the optical output terminal of the photoconductor is equipped with a condensing lens. (6) The semiconductor inspection device according to claim 1, wherein the supporting base is provided with a metal probe.