JP4849709B2 - Measuring device for flatness etc. - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a flatness measuring apparatus that mainly measures flatness of a large number of pins such as an IC chip using a laser displacement sensor or the like.
[0002]
[Prior art]
In the prior art, for example, when measuring the flatness of a large number of pins such as an IC chip, the chip is placed on a flat reference plate, and the laser is detected from a laser displacement sensor provided above the pins. The position of each pin was measured.
[0003]
[Problems to be solved by the invention]
In the above-described prior art, the flat reference surface must be determined virtually (virtual flat reference surface). For example, in the case of a chip having a large number of pins (lead: 40 poles on one side, etc.) on each side of the quadrangle, the pin that is projected upward on each side is detected from the position of the detected pin. The virtual flat reference plane is determined with the triangular plane connecting the vertices of the three pins excluding the pin that is the least out of the flat reference plane, and how far each pin is recessed from the virtual flat reference plane. It was to measure whether it was in the site. For this reason, there is a problem that optical measurement “cannot measure the center row” and spatial measurement “unknown true reference plane in multiple rows”. In such a conventional technique, when the chip body is warped as shown in FIG. 10, the virtual flat reference plane itself is wrong due to the warp, and as a result, a floating pin exceeding the floating reference may be generated. The number of pins has been increased by placing the pins on a flat mounting substrate (mounting stage) and soldering or fitting them into the connector, resulting in many mounting defects.
[0004]
The present invention has been made in view of the above-described problems of the prior art, and its purpose is flatness and the like that enable measurement of the position of a chip pin or the like on an absolute flat (planar) reference surface. To provide a measuring device.
[0005]
[Means for Solving the Problems]
The present invention is described below in order to achieve the above-mentioned object.
An optical sensor is a laser autofocus sensor for sensing the reflected light of the particular light beam impinging on the measurement object irradiates the specific light consisting of laser beam by the focusing,
A drive unit that horizontally moves the light sensor;
A light transmissive flat plate provided in parallel with the horizontal movement surface of the photosensor;
A flat reference surface on which the measurement object consisting of the outer surface of the light-transmitting flat plate is directly placed ;
A first reflected light beam that can be sensed by the optical sensor by reflecting a part of the specific light beam that is irradiated from the optical sensor and attempts to pass through the light-transmissive flat plate by the flat reference surface that is a first reflective surface. And the specific light beam that has passed through the light-transmissive flat plate is reflected by the measurement portion of the measurement object that is the second reflection surface, and is more sensitive than the first reflected light beam that can be sensed by the optical sensor. A thin film such as a vapor deposition film for obtaining a predetermined transmission characteristic of the specific wavelength range light, which is the specific light, applied to both surfaces of the light transmissive flat plate so as to obtain a strong second reflected light beam. such from the Rutotomoni,
In a state where there is the first reflected light beam and the second reflected light beam at a place where the measurement object is present, the first reflected light beam that is a weak reflected light beam is not focused and is a strong reflected light beam. The second reflected light beam is focused and the second reflected light beam can be measured , and the first reflected light beam is focused and the second reflected light beam can be measured at a place where there is no measurement object. The transmission characteristic is set so that the relationship between the first reflected light beam that is a weak reflected light beam and the second reflected light beam that is a strong reflected light beam is set so that one reflected light beam can be measured .
A flat reference point is calculated from the sensing data of the first reflected light beam, and a distance from the flat reference point to the measurement point of the measurement object is calculated from the sensing data of the second reflected light beam. It is a measuring device for flatness and the like.
[0006]
A chip having a large number of pins (leads) on all sides of a square, for example, is placed on the flat reference surface so that the pins are placed directly on the flat reference surface. Irradiate a measurement object with a specific light beam from an optical sensor (for example, an autofocus sensor), and detect the reflected light beam from the measurement object with a light sensor (in the case of an autofocus sensor, by focusing), from a flat reference surface Measure the distance (floating distance) to the measurement object. Since the three pins that protrude most among the four sides hit the flat reference plane and the chip is placed, it is placed on a flat mounting board as it is and mounted, so accurate pin position measurement without error Is realized.
[0007]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described with reference to the drawings.
<Embodiment 1> FIG. 1 is a block diagram of an apparatus for measuring flatness, etc. according to Embodiment 1 of the present invention, FIG. 2 is a block diagram of a measurement portion of the same Embodiment 1, and FIG. FIG. 4 is a screen diagram in which the measurement results in the configuration diagram of FIG. 3 are displayed as waveforms on a monitor, and FIGS. 5, 6, 7 and 8 are quadrangular shapes in which a large number of pins are provided in a four-sided row. It is the screen figure which displayed the measurement result of each side row of a chip on the monitor.
[0008]
The flatness (planar) degree measuring device 1 irradiates a specific light beam 2 and senses a reflected light beam of the specific light beam 2 hitting the measurement object (body) 3 and horizontally moves the light sensor 5. The specific light 2 irradiated from the drive unit 6 and the optical sensor 5 is transmitted and hits the measurement object 3, and the intensity by which the optical sensor 5 can detect the reflected light 4 reflected and reflected by the measurement object 3 is transmitted. The light transmission plane plate 7 provided in parallel with the horizontal movement surface of the optical sensor 5 and the outer surface of the light transmission plane plate 7 and for directly placing the measuring object 3 A horizontal moving surface and a horizontal flat (planar) reference surface 8 of the optical sensor 5 located inside the light-transmitting flat plate 7, and a flat reference surface of the measurement portion 9 of the measurement object 3 based on the sensing data of the optical sensor 5. Calculated the position (floating distance) from 8 A specific light beam which is composed of a control unit 10 for controlling the driving unit 6 and the like, a display monitor 11 for measurement / control, and a printer 12 and which is emitted from the optical sensor 5 and is transmitted through the light-transmissive flat plate 7 2 is reflected by the flat reference surface 8 to obtain a first reflected light beam that can be sensed by the optical sensor 5, and the specific light beam 2 transmitted through the light-transmissive flat plate 7 is reflected by the measurement object 3. Then, the transmission characteristic of the transmissive flat plate 7 is set so that a second reflected light beam that can be detected by the optical sensor 5 by returning and transmitting through the light transmissive flat plate 7 is obtained, and the detection data of the first reflected light beam is used. The flat reference point 11 is calculated, and the distance from the flat reference point 12 to the measurement portion (measurement point of the pin) 9 of the measurement object 3 is calculated based on the second reflected light sensing data.
[0009]
An optical sensor (optical displacement type) 5 is a laser focus sensor ( focus distance measuring method : resolution 0.01 μm), and a specific light beam 2 to be irradiated uses a laser beam of 670 nm. The light-transmitting flat plate 7 is a vapor-deposited film containing magnesium fluoride as a main component on both surfaces of the glass flat plate (by vacuum evaporation) so that the transmittance of the specific light 2 which is a laser beam of 670 nanometers is 98% or more. Is given. Reflection from the flat reference surface 8 is less than 2%. The flat reference surface 8 is processed with flatness polished to a flatness of about 3 μm or less. The light transmissive flat plate is a glass plate as it is so that the reflection is large and the reflected light from the measurement object cannot be sufficiently detected by the optical sensor. The transmittance of the light-transmitting flat plate varies depending on the light reflection characteristics of the object to be measured, but it is preferably 95% or more and the reflectance is about 2% to 5%. Deposition of vapor deposition materials such as magnesium fluoride, aluminum, platinum, gold, silver, copper, chromium, silicon, nickel, titanium pentoxide, germanium, titanium dioxide, silicon monoxide, silicon dioxide, etc. Multilayer) makes it possible to make the laser in the target frequency range have the target transmittance. This differs depending on the company or worker, and is largely based on know-how.
[0010]
The specific light beam 2 irradiated at the site where the measurement object 3 is placed includes a first reflected light beam and a second reflected light beam. Of course, this is because the lift (distance) of the measurement object from the flat reference surface 8 is examined, and the second reflected light beam is measured. In this case, in order to avoid the first reflected light beam, the first reflected light beam is removed from the measurable range, and the second reflected light beam is measured, and the amount of lifting of the measuring object 3 from the flat reference surface 8 is maximized. The relationship that can be measured is set.
[0011]
As shown in FIG. 2, since the measurement part 9 which is the tip of the pin (lead) 13 of the measurement object 3 is directly placed on the flat reference surface 8 and measured, the measurement part 9 is placed on the mounting base and the measurement part 9 Since measurement is performed under the same conditions as those in contact with the mounting substrate, it is measured with an absolute flat reference surface (absolute flat reference surface) in the same state as the actual mounting conditions, not the virtual flat reference surface. . That is, even if the measurement object 20 is warped as shown in FIG. 2 , the actual flatness can be measured because the measurement is performed under the same measurement conditions as the mounting conditions on the mounting substrate.
[0012]
In FIG. 3, a measurement object 27 having four rows of pins 23, 24, 25, and 26 is set on the flat reference surface 8 with five rows of pins 22. 4 shows a measurement result screen in which the measurement result of the measurement object 27 in FIG. The second pin of the pin row 23, the fifth pin of the pin row 25, and the third pin of the pin row 26 are the most protruding pins in each row. A flat reference surface is formed. It is shown how much other pins are floating from the contact portion of the three pins, that is, the flat reference surface 8. The higher the waveform, the greater the floating distance.
[0013]
5, 6, 7, and 8, a measurement result screen of a measurement object (not shown) 27 having quadrangular pin rows 30, 31, 32, 33 (one row of 15 pins) is displayed on the monitor 11. Has been. Since the 4th pin of the pin row 30, the 14th pin of the pin row 31, and the 8th pin of the pin row 32 are the most protruding pins in each row, these 3 pins are in contact with the flat reference surface 8 and are absolutely A flat reference surface is formed. It is shown how much other pins are floating from the contact portion of the three pins, that is, the flat reference surface 8. The higher the waveform, the greater the floating distance. The light intensity of the light sensor can be adjusted.
In the description of the following embodiment, the same reference numerals are given to the same components as those of the above-described embodiments, and the description thereof is omitted.
[0014]
<Embodiment 2>
FIG. 9 is a block diagram showing a measuring apparatus for flatness etc. according to Embodiment 2 of the present invention. Flatness and the like measuring device 40, in addition to the configuration of the flatness or the like measuring device 1, the light sensor for horizontally moving integrally the same as the light sensor 5 to the opposite side of the optical sensor 5 of the light transmissive flat plate 7 5 is a high-precision measurement that measures the vertical movement distance of a vertical driving unit (not shown) that vertically moves the optical sensor 41 and the optical sensor 41 that is vertically moved by the vertical driving unit. A high-resolution scale sensor 44 (measurable range: 50000 μm, resolution: 0.005 μm) is provided. In order to move the optical sensor 5 and the optical sensor 41 integrally, the horizontal driving means 43 fixes the optical sensor 5 to the integrated sensor fixing arm 45 and the optical sensor 41 to the sensor fixing arm 46 . The sensor fixing arm 45 and the sensor fixing arm 46 are horizontally moved integrally. The flatness of both surfaces of the measurement object 42 in a state where the measurement object 42 is placed on the flat reference surface 8 and the thickness can be measured at the same time. The optical sensor 41 is moved to a part off the measurement object 42, vertically lowered, and the position of the flat reference surface 8 is measured and memorized by the photolysis scale sensor 44. Depending on the measurement object, the position of the measurement object is placed after the position of the flat reference surface is measured in an empty state. By measuring the upper surface of the measuring object 42 with the optical sensor 44, the shape of the upper surface can be measured. The position A of the upper surface measured by the optical sensor 44 is calculated from the stored flat reference surface position, and the distance B from the flat reference surface can be obtained. The thickness C of the measurement object can be obtained by negatively calculating the distance (floating distance) from the flat reference surface measured by the optical sensor 5 to the lower surface of the measurement object 42 from the distance B from the flat reference surface. I can do it. In the conventional technique for measuring the thickness of a measurement object, the thickness was measured by applying a measurement beam from both sides of the measurement object. In this case, a high point for determining a reference point (middle point) is used. An accurate calibration gauge was provided, and a high-accuracy scale sensor was provided to measure the distance traveled by moving both sensors vertically. That is, since two expensive scale sensors are required, the cost is high. The flatness measuring device 40 does not require this calibration gauge and one scale sensor, so that the device can be made inexpensive.
[0015]
【The invention's effect】
Since the present invention is as described above, the following effects can be obtained.
An optical sensor that is a laser autofocus sensor that irradiates a specific light beam composed of a laser beam and senses the reflected light beam of the specific light beam that hits the measurement object by focusing, a drive unit that horizontally moves the optical sensor, and the light A light-transmitting flat plate provided in parallel with the horizontal movement surface of the sensor, a flat reference surface on which the measurement object consisting of an outer surface of the light-transmitting flat plate is directly placed, and the light transmitting from the light sensor. A portion of the specific light beam that is about to pass through the reflective flat plate is reflected by the flat reference surface, which is a first reflective surface, to obtain a first reflected light beam that can be sensed by the optical sensor, and the light transmission property the specific light transmitted through the flat plate second stronger than the measurement portion the optical sensor is reflected by the sensible for the first reflected light beam of the measurement object is a second reflective surface For such reflected beam is obtained, and it and a thin film such as deposited film to obtain a predetermined transmission characteristic of the specific wavelength band light is a particular light beam applied to both surfaces of the light transmissive flat plate In addition , in a state where the first reflected light beam and the second reflected light beam at a place where the measurement object is present, the first reflected light beam that is a weak reflected light beam is not focused, The second reflected light beam, which is a strong reflected light beam, is focused and the second reflected light beam can be measured , and the focus is adjusted to the first reflected light beam at a place where the measurement object is not present. The transmission characteristic is set so that the first reflected light beam, which is a weak reflected light beam, and the second reflected light beam, which is a strong reflected light beam, are set so that the first reflected light beam can be measured. First reflected ray sensing data A flat reference point is calculated by a sensor, and a distance from the flat reference point to a measurement point of the measurement object is calculated from the second reflected light sensing data. So
For example, it is possible to obtain an accurate total flat characteristic in a state where the chip is placed on a mounting board that is actually mounted regardless of warping of the chip body. As a result, it is possible to solve the problems of the optical measurement “cannot measure the central column” and the spatial measurement “the true reference planes in a plurality of columns are unknown”, which was a problem of the prior art. In chips with a large number of pins, defective products can be reliably identified and removed, so that there are virtual measurement conditions and actual mounting conditions that are affected by the warpage of the chip body as in the prior art. There is an effect that it is possible to eliminate mounting defects resulting from the difference. In other words, quality can be quantitatively measured, evaluated and improved in reliability.
[0016]
The flat reference point is calculated from the sensing data of the first reflected light (flat reference surface), and the distance from the flat reference point to the measuring point of the measuring object is calculated from the sensing data of the second reflected light (measuring object). Thus, the flat reference plane can be determined without requiring any special adjustment, so that there is an effect of realizing an apparatus capable of measuring immediately without error.
[0017]
[Brief description of the drawings]
FIG. 1 is a configuration diagram of a flatness etc. measuring apparatus according to a first embodiment of the present invention.
FIG. 2 is a configuration diagram of a measurement part according to the first embodiment of the present invention.
FIG. 3 is a configuration diagram of a measurement part according to the first embodiment of the present invention.
4 is a screen view in which the measurement results in the configuration diagram of FIG. 3 of the present invention are displayed as waveforms on a monitor.
FIG. 5 is a screen view in which a measurement result of a first side row of a square chip in which a large number of pins are provided in the four side row of the present invention is displayed on a monitor.
FIG. 6 is a screen view in which a measurement result of a second side row of a quadrangular chip in which a large number of pins are provided in the four side row of the present invention is displayed on a monitor.
FIG. 7 is a screen view in which a measurement result of a third side row of a rectangular chip in which a large number of pins are provided in the four side row of the present invention is displayed on a monitor.
FIG. 8 is a screen view in which a measurement result of a fourth side row of a quadrangular chip in which a large number of pins are provided in the four side row of the present invention is displayed on a monitor.
FIG. 9 is a configuration diagram showing a flatness etc. measuring apparatus according to a second embodiment of the present invention.
FIG. 10 is a configuration diagram of a conventional flatness measuring apparatus.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Flatness etc. measuring apparatus 2 ... Specific light beam 3 ... Measurement object 4 ... Warping part 5 ... Optical sensor 6 ... Drive unit 7 ... Light transmissive flat plate 8 ... Flat reference surface 9 ... Measurement part 10 ... Control unit 11 ... Monitor 12 ...・ Printer 13 ... Pin 22 ... Pin 23 ... Pin row 24 ... Pin row 25 ... Pin row 26 ... Pin row 27 ··· Measurement object 30 ··· Pin row 31 ··· Pin row 32 · · · Pin row 33 · · · Pin row 40 · · · Measuring device for flatness, etc. 41... Optical sensor 42 .. Measurement object 43... Horizontal driving means 44... High resolution scale sensor 45. ... Optical sensor fixed arm 50 ... Platformity measuring device 51 of the prior art ... Sensor horizontal movement drive unit 52 ... Laser focus sensor 53 ... Measurement object table 54..Specific rays

Claims (1)

An optical sensor is a laser autofocus sensor for sensing the reflected light of the particular light beam impinging on the measurement object irradiates the specific light consisting of laser beam by the focusing,
A drive unit that horizontally moves the light sensor;
A light transmissive flat plate provided in parallel with the horizontal movement surface of the photosensor;
A flat reference surface on which the measurement object consisting of the outer surface of the light-transmitting flat plate is directly placed ;
A first reflected light beam that can be sensed by the optical sensor by reflecting a part of the specific light beam that is irradiated from the optical sensor and attempts to pass through the light-transmissive flat plate by the flat reference surface that is a first reflective surface. And the specific light beam that has passed through the light-transmissive flat plate is reflected by the measurement portion of the measurement object that is the second reflection surface, and is more sensitive than the first reflected light beam that can be sensed by the optical sensor. A thin film such as a vapor deposition film for obtaining a predetermined transmission characteristic of the specific wavelength range light, which is the specific light, applied to both surfaces of the light transmissive flat plate so as to obtain a strong second reflected light beam. such from the Rutotomoni,
In a state where there is the first reflected light beam and the second reflected light beam at a place where the measurement object is present, the first reflected light beam that is a weak reflected light beam is not focused and is a strong reflected light beam. The second reflected light beam is focused and the second reflected light beam can be measured , and the first reflected light beam is focused and the second reflected light beam can be measured at a place where there is no measurement object. The transmission characteristic is set so that the relationship between the first reflected light beam that is a weak reflected light beam and the second reflected light beam that is a strong reflected light beam is set so that one reflected light beam can be measured .
A flat reference point is calculated from the sensing data of the first reflected light beam, and a distance from the flat reference point to the measurement point of the measurement object is calculated from the sensing data of the second reflected light beam. Measuring device for flatness etc.

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