JP2591347B2 - Mounting board inspection equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a mounting board inspection apparatus, and more particularly to a mounting board inspection apparatus for observing a high-speed electric signal waveform by utilizing an electro-optic effect.

[0002]

2. Description of the Related Art As shown in FIG. 7, a conventional mounting board inspection apparatus has a fixture 22 having a large number of probes 23 and a tester 21 electrically connected to each probe by a cable or the like. . The probe 23 is brought into contact with a test terminal on the mounting board 1 or an input / output terminal of a component such as an LSI, and an electric signal is input from the tester to the component to be measured mounted on the board from the tester, and the output electric signal is output. Is measured to observe the electric signal waveform of the measured component.

A mounting board inspection apparatus that does not use a probe is described in Japanese Patent Application Laid-Open No. 3-167490. In this apparatus, a voltage or an induced voltage is optically measured by bringing an electro-optic crystal into contact with or close to an object to be measured.

[0004]

In this conventional mounting board inspection apparatus, since a large number of probes are brought into contact with test terminals or input / output terminals of components, the operating condition of the components changes due to the contact resistance (capacitance). However, a correct electric signal waveform cannot be observed for an ultra-high-speed component having a small operation margin.

On the other hand, with regard to a higher-density mounting board, the terminal to be brought into contact with the probe is only a few tens of μm, which makes it difficult to make contact with the probe, and the probe becomes thinner to facilitate the contact. However, there is a problem that the life of the device is shortened and a large investment is required.

In the conventional apparatus using the electro-optic effect without using the above-described probe, it is difficult to accurately measure the electric field to be measured when the apparatus is brought close to the apparatus. Further, when the contact is made, if the height of the object to be measured varies, all the measurement objects cannot be measured accurately.

It is an object of the present invention to provide an apparatus capable of accurately measuring a high-speed electric signal waveform without measuring a high-density mounting board with a probe without contacting an object to be measured. Further, the present invention provides an apparatus that can accurately and inexpensively measure a high-density mounting board, which has been difficult to measure with a conventional apparatus using a probe. Alternatively, compared to the conventional measurement device using the electro-optic effect,
In addition, an object of the present invention is to provide an apparatus that can accurately measure even a measurement object on a mounting board having a variation in height.

[0008]

A mounting board inspection apparatus according to the present invention comprises a transparent metal layer on the upper surface, a reflector on the lower surface, and a projection.
A sensor element comprising an electro-optic effect object provided with a divided high dielectric elastomer , a laser light source,
Optical means for passing the laser light from the laser light source into the sensor element or reflecting the laser light to the reflection plate and passing the laser light, and between the transparent metal layer and the reflection plate of the sensor element. There is provided a detecting means for detecting the modulation degree of the modulated laser light which has been modulated by passing through or reflecting through the electro-optical object affected by the generated potential difference.

Alternatively, the mounting board inspection device of the present invention is divided into a transparent metal layer on the upper surface, a reflector and a projection on the lower surface.
Board provided with a plurality of sensor elements made of an electro-optical effect object provided with a highly dielectric elastomer provided, a laser light source, and a laser beam from the laser light source passing through the sensor element or the reflecting plate Optical means for injecting a laser beam so as to reflect and pass through, and pass or reflect and pass through an electro-optical object affected by a potential difference generated between the transparent metal layer of the sensor element and the reflector. Means for detecting the degree of modulation of the modulated laser light which has been modulated.

Further, the mounting board inspection apparatus of the present invention has a metal layer on an upper surface, a reflector on a lower surface, and a high- intensity divided into projections.
A sensor element comprising an electro-optic effect object provided with an electro-elastomer , two laser light sources, and a laser beam from the laser light source passing through the sensor element or reflected by the reflection plate and passing therethrough. Optical means for injecting laser light into the optical element, and modulation by passing or reflecting and passing through an electro-optic effect object affected by a potential difference generated between the transparent metal layer and the reflector of the sensor element. And two detecting means for detecting the degree of modulation of the modulated laser light that has received the modulated laser light.

[0011]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. FIG. 1 is an overall configuration diagram of a mounting board inspection apparatus according to one embodiment of the present invention. The sensor element 2 is brought into contact with an object to be measured on the mounting board 1, and the mounting board is set on the board mounting table 3. Board drive device 10 incorporating a clock circuit, power supply, etc. for operating components on a mounting board
Thus, the object to be measured on the mounting board obtains a certain electric signal. As will be described in detail later, the sensor element 2 generates an electric field in the electro-optical effect object by the electric signal.

A laser light is output from a laser light source 6 and enters a laser light scanning unit 5 via a beam splitter 4.
The light is focused toward the measurement point of the sensor element and projected vertically. The projected laser light is reflected by the reflection plate of the sensor element and returns to the light scanning section 5 again. At this time, in the process of reflecting and reciprocating the electro-optical object, the plane of polarization changes due to the electro-optical effect due to the electric field generated in the electro-optical object. The laser beam returned to the laser beam scanning unit 5 again enters the light receiving unit 7 again via the beam splitter 4, and a change in the polarization state is detected. The control mechanism 8 controls the board driving device 10, the laser light source 6, and the laser light scanning unit 5 to continuously measure the change in the polarization state, performs signal processing in the signal processing mechanism 9, and performs signal processing. Measure the electrical signal of the object.

Next, the sensor element will be described in detail. FIGS. 2 and 3 are a top view and a side view when the sensor element of the first embodiment is brought into close contact with an object to be measured.
(A). The sensor element is LiNbO ₃ , KDP,
On the upper surface of an electro-optic object 13 made of an electro-optic effect crystal such as GaAs or an electro-optic effect polymer mixed with a dye such as DANS or DR1, I made of indium, tin or oxide
A transparent metal layer 14 which is a TO film, a reflecting plate 15 made of a metal such as Al or Ag or a dielectric multilayer film is deposited on the lower surface, and a high dielectric elastomer 16 is coated on the reflecting plate 15 with a conductive adhesive or the like. Glued.

Reflector 15 and High Dielectric Elastomer 1
6 is processed by a printing / etching technique or a laser so as to divide the electro-optical object 13 into a protruding shape. The size of the protrusions and the distance between the protrusions depend on the lead terminals that are the DUTs or the width of the wiring connected to the lead terminals. It is calculated in advance so that it does not come into contact with the object at the same time.

When the sensor element is brought into contact with the object to be measured, a fringe electric field generated from the object to be measured generates a high dielectric elastomer 16 and a reflector 15 of the contacting projection.
Through it into the electro-optic object 13. At this time, the transparent metal layer 14 deposited on the upper surface of the sensor element is GN
Since it is grounded at the D level, the electric field in the electro-optical object 13 goes to the upper surface direction without leaking in the lateral direction.

Since the high-dielectric elastomer 16 has flexibility, even if there is a spatial gap due to variations in height in each of the objects to be measured, the gap can be filled, and projections are formed on all the objects to be measured. It is possible to make contact.

FIG. 3B is a side view when the sensor element of the second embodiment is brought into close contact with the object to be measured. The insulator 1 has a thickness between the projections of the sensor element of the first embodiment that is greater than the thickness of the reflector 15 and lower than the surface of the projection.
Fill in 8. Accordingly, it is possible to prevent the reflection plate 15 from deteriorating due to corrosion or the like, improve the physical strength of the projection, and prevent the projection from being bent and touching the projection that is in contact with a different object to be measured.

Next , the second aspect of the present invention will be described with reference to the drawings. FIG. 4 is an overall configuration diagram of a mounting board inspection apparatus according to one embodiment of the present invention. The sensor board 19 is combined with the mounting board 1 and installed on the board mounting table 3.
Other devices are the same as those shown in FIG. 1, and the operation is the same.

The sensor board 19 will be described in detail. FIG. 5 shows a top view of the sensor board 19. The board made of insulating material is the design drawing of the mounting board or CA
The sensor element 2 is hollowed out according to D design data or the like so as to contact a lead terminal of a component 20 such as an LSI to be measured or a wiring on a board. At this time, parts such as high-height components and connectors that are detrimental to bringing the sensor element 2 into contact with the object to be measured are also cut out at the same time. The sensor element 2 is adhered only to the side surface to the hollowed portion, and is arranged so as to be in contact with the object to be measured. The sensor elements are the same as those described above with reference to FIG.

Next, the invention of claim 3 will be described with reference to the drawings. FIG. 6 is an overall configuration diagram of a mounting board inspection apparatus according to one embodiment of the present invention. The sensor element 2 is brought into contact with the mounting board 1 on the object to be measured on the front and back sides, and is set up on the board mounting table 3 so that the front and back sides of the mounting board are horizontal. An object to be measured on the mounting board obtains a certain electric signal by the board driving device 10 incorporating a clock circuit, a power supply, and the like for operating components on the mounting board. The sensor element is the same as that described above, and an electric field is generated in the electro-optic effect object by the electric signal.

A laser beam is output from a laser light source (1) 6A on the front side of the mounting board, that is, on the left side in FIG. 6, and a laser beam scanning unit (1) 5A is passed through a beam splitter (1) 4A.
, Is collected toward the measurement point of the sensor element, and is projected vertically. The projected laser light is reflected by the reflection plate of the sensor element and returns to the laser light scanning unit (1) again. At this time, in the process of reflecting and reciprocating the electro-optical effect object, the polarization plane changes due to the electro-optical effect due to the electric field generated in the electro-optical effect object. The laser beam returned to the laser beam scanning unit (1) is again transmitted to the beam splitter (1).
Then, the light is incident on the light receiving section (1) 7A, and a change in the polarization state is detected.

The laser light source (2) 6B, the beam splitter (2) 4B, the laser beam scanning unit (2) 5B, and the light receiving unit (2) 7B on the rear side of the mounting board, on the right side in FIG. The change in the polarization state of the electro-optic effect object of the sensor element in contact with the object to be measured on the back side is detected.

The board driving device 1 is controlled by the control mechanism 8.
0, laser light source (1) 6A, laser light scanning unit (1) 5
A, laser light source (2) 6B, laser light scanning unit (2) 5B
, The change in the polarization state is continuously measured, the signal processing mechanism 9 performs signal processing, and the electric signal of the object to be measured is measured. Electrical signals can be measured simultaneously on the front and back sides of the mounting board.

For a mounting board on which components are mounted on both sides or a mounting board where components are mounted at high density and the sensor element must be brought into contact with the lead terminals or wiring on the back surface, Inspection time can be greatly reduced as compared to a mounting board inspection apparatus that inspects only one side at a time.

[0025]

As described above, according to the first aspect of the present invention, the sensor element, the laser light source, and the laser light from the laser light source pass through the inside of the sensor element or reflect through the reflection plate of the sensor element. And a modulated laser modulated by passing through or reflecting through an electro-optic object affected by a potential difference between a transparent metal layer of a sensor element and a reflector. A detection unit for detecting the degree of light modulation is provided.

This eliminates the need to bring the probe into contact with the object to be measured, thereby preventing the operation state of the component from being changed by the contact resistance (capacitance) and facilitating the measurement of a portion difficult to contact with the probe. In addition, it has the effect of reducing investment due to probe breakage.

Furthermore, since a high dielectric elastomer is provided in the sensor element as compared with a conventional measuring device using the electro-optic effect, the sensor element can be adhered without damaging the object to be measured, and an electric signal can be obtained. Can be measured accurately. In addition, accurate measurement can be performed with good reproducibility even when the object to be measured has a variation in height.

According to a second aspect of the present invention, there is provided a sensor board in which a sensor element is arranged to be in contact with an object to be measured, a laser light source, and a laser beam from the laser light source passing through the sensor element or a sensor. An optical means for injecting a laser beam so as to reflect and pass through the reflector of the element, and pass or reflect through an electro-optic effect object affected by a potential difference generated between the transparent metal layer of the sensor element and the reflector. Detecting means for detecting the degree of modulation of the modulated laser light that has been modulated by passing through it. This eliminates the need for the probe to be in contact with the object to be measured, thus preventing the operating state of the component from changing due to the contact resistance (capacitance), facilitating the measurement of parts that are difficult to contact with the probe, and Investment in probe damage

Further, according to the present invention, since the object to be measured and the electro-optical element can be arranged in advance, the displacement of the electro-optical element with respect to the object to be measured can be eliminated. In addition, even when the laser light and the electro-optical element are misaligned, an electric signal is not detected in a portion where the electro-optical element does not exist.
An erroneous signal is not detected, and only a signal from the device under test can be accurately measured.

According to a third aspect of the present invention, the sensor element, the two laser light sources, and the laser light from the laser light source do not pass through the inside of the sensor element or are reflected by the reflection plate of the sensor element and pass therethrough. Modulated by passing through or reflecting through an electro-optic effect object affected by a potential difference between the transparent metal layer of the sensor element and the reflector, and two optical means for injecting laser light into the It is provided with two detecting means for detecting the modulation degree of the modulated laser light.

This eliminates the need to bring the probe into contact with the object to be measured, thereby preventing the operation state of the component from being changed by the contact resistance (capacitance), and facilitating the measurement of a portion that is difficult to contact with the probe. In addition, it has an effect of reducing investment due to breakage of the probe. Furthermore, both the front and back surfaces of the board can be measured simultaneously, and the measurement time can be reduced.

[Brief description of the drawings]

FIG. 1 is an overall configuration diagram of a mounting board inspection apparatus according to an embodiment of the present invention.

FIG. 2 is a top view when the sensor element according to one embodiment of the present invention is brought into close contact with an object to be measured.

FIGS. 3A and 3B are side views when the sensor element in the embodiment of the present invention is brought into close contact with an object to be measured.

FIG. 4 is an overall configuration diagram of a mounting board inspection apparatus according to one embodiment of the present invention.

FIG. 5 is a top view of a sensor board according to one embodiment of the present invention.

FIG. 6 is an overall configuration diagram of a mounting board inspection apparatus according to one embodiment of the present invention.

FIG. 7 is a view for explaining a conventional mounting board inspection apparatus.

[Explanation of symbols]

REFERENCE SIGNS LIST 1 mounting board 2 sensor element 3 board mounting base 4 4A, 4B beam splitter 55 5A, 5B laser light scanning part 66A, 6B laser light source 77A, 7B light receiving part 8 control mechanism 9 signal processing mechanism 10 board driving device 11 Target part 12 Board wiring 13 Electro-optical object 14 Transparent metal layer 15 Reflector 16 High dielectric elastomer 17 Object to be measured 18 Insulator 19 Sensor board 20 Parts 21 Tester 22 Fixture 23 Probe

 ──────────────────────────────────────────────────続 き Continuation of front page (72) Inventor Toshio Ishiyama 5-7-1 Shiba, Minato-ku, Tokyo Within NEC Corporation (56) References JP-A-3-180778 (JP, A) JP-A-3 -48171 (JP, A) JP-A-6-160495 (JP, A) JP-A-63-256864 (JP, A)

Claims (3)

(57) [Claims] 1. A transparent metal layer on an upper surface, a reflector and a protrusion on a lower surface.
A sensor element composed of an electro-optic effect object provided with a high dielectric elastomer divided in an erected manner , a laser light source, and a laser beam from the laser light source passing through the sensor element or reflecting on the reflection plate. Optical means for injecting a laser beam so as to pass through, and passing or reflecting and passing through an electro-optical object affected by a potential difference generated between the transparent metal layer and the reflector of the sensor element. Detecting means for detecting the degree of modulation of the modulated laser beam modulated by the mounting board inspection apparatus. 2. A transparent metal layer on an upper surface, and a reflector and a protrusion on a lower surface.
A sensor board including a plurality of sensor elements made of an electro-optical effect object provided with a high dielectric elastomer divided in a raised shape , a laser light source, and a laser beam from the laser light source passing through the inside of the sensor element Or an optical means for injecting a laser beam so as to reflect and pass through the reflector, and pass or pass through an electro-optical object affected by a potential difference generated between the transparent metal layer of the sensor element and the reflector. A mounting board inspection apparatus, comprising: a detection unit configured to detect a modulation degree of a modulated laser beam modulated by being reflected and passed. 3. The mounting board inspection apparatus according to claim 1, further comprising two each of the laser beam, the optical unit, and the detection unit.