JPH06294779A - Ultrasonic apparatus and method for image inspection - Google Patents

Abstract

PURPOSE:To detect a state of exfoliation or the like inside IC without necessitating skill, by generating contour data by subjecting smoothed measured data or display data to secondary differentiation, and by obtaining a clear image by adjusting the gain of an echo signal or the focus of a probe. CONSTITUTION:An ultrasonic flaw detecting part 6 transmits a transmission pulse to a probe 4, receives an echo signal from a sample 1 and sends it to a peak detecting part 7. The detecting part 7 extracts a peak value of a received echo, subjects it to A/D conversion 8 and then sends the converted value to a measured data processing device 16. After storing the sent data in a memory 14e, MPU 9 executes an image smoothing processing program 14a to remove noise and generates display data on a smoothed image. In succession, it executes an edge emphasizing processing program 14b and extracts the contour of the display data by Laplacian (secondary differentiation) so as to emphasize an edge. When a clear image is not obtained, adjustment can be executed simply by adjusting a gain or a focus. Then, an inspecting region binary-coding processing program 14c is executed, the area of a place of exfoliation is calculated and the quality of the sample is determined.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ultrasonic image inspection apparatus and its inspection method, and more specifically, it can easily display a clear image of a peeling state or void of an adhesive material inside a component such as an IC. Ultrasonic image inspection apparatus capable of performing

[0002]

2. Description of the Related Art An ultrasonic image inspection apparatus, which is one of ultrasonic measurement apparatuses, is capable of, for example, focusing on a predetermined depth position of a component to be inspected and collecting a C scope image at that position. The sampling is performed by applying a gate to the echo reception signal (video signal, RF signal, etc.) obtained from the inspected component in correspondence with the focal point position to determine the magnitude of the echo height (peak value) of the echo reception signal. By converting to a luminance or color signal.

In the inspection of ICs among electronic components, in addition to the electrical characteristics, the adhesion state between the chip and the base on which it is mounted determines the quality of the product. The condition and voids are inspected.
When the chip and the base are peeled off, the reflection intensity there is high, so if there is an echo reception signal with a level above a certain level, if that part is made a red color signal, the peeling or void part will be It can be displayed as a red image.
This makes the peeled state and voids clear.

[0004]

However, in general, in the ultrasonic measuring device, since the signal level of the echo reception signal can be adjusted, the gain (amplification rate or attenuation rate of the echo reception signal) is adjusted. Just by doing so, the level of the echo reception signal changes greatly, and the part displayed in red becomes larger or smaller as a whole. Also,
If the gain is reduced, the peeling state and voids will not be displayed in red. Therefore, it is difficult to obtain a clear image corresponding to peeling, and there are many erroneous determinations of the peeled state and voids.

The C-scope image focuses the inspection surface and collects the inspection image there, but the signal level of the echo reception signal also changes due to the positional deviation of the focusing. Due to this, the content of the displayed image is also different, and an erroneous determination of the peeled state or void occurs. Furthermore, the state of the measurement image changes depending on the selection of the probe used and the focal length.

These are common not only to the inspection of the peeling state and the voids but also to the image inspection by the ultrasonic wave. In the ultrasonic image inspection apparatus, the echo depending on the inspection contents of the inspected part is echoed. It is necessary to optimally set the gain for the received signal. The setting of the gain, selection of the probe, and focusing are performed by a skilled person according to the component to be inspected and the inspection content, and it is necessary to collect the basic data many times. Therefore, at present, it is difficult for an expert to set the optimum gain or focus.

Recently, the ultrasonic image inspection apparatus is used for nondestructive inspection of various parts, and there is a demand that it can be operated by not only a skilled person but also a person who is not familiar with ultrasonic measurement. The object of the present invention is to solve the above-mentioned problems of the prior art and to meet the above-mentioned demands, and anyone can obtain a clear image of the peeling state or void of the adhesive material inside a component such as an IC. An object of the present invention is to provide an ultrasonic image inspection apparatus and an inspection method thereof that can be easily obtained.

[0008]

The features of the ultrasonic image inspection apparatus of the present invention that achieves the above object are that a focus type probe and an echo reception signal from the probe are driven to amplify the received echo reception signal. Alternatively, it has an ultrasonic flaw detection unit that attenuates to obtain a measurement signal, and sets the focus position of the probe to a predetermined position inside the inspection object and displays a cross-sectional image of the inspection object according to the measurement signal. In the sonic image inspection device, smoothing processing means for performing a smoothing process on the measurement data or display data of the article to be inspected obtained according to the measurement signal, and a secondary for the smoothed measurement data or display data. It is provided with a contour data generating means for performing a differentiating process to generate contour data, and a contour display means for displaying a contour image according to the contour data. Attenuation factor is one that can be adjusted from the outside.

Further, in the inspection method of the present invention, smoothing processing is performed on the measurement data or display data of the article to be inspected, and the second derivative processing is performed on the smoothed measurement data or display data. The contour data is generated to display the contour image based on the contour data, and when the displayed contour image is not appropriate, the gain of the echo reception signal of the inspected article or the focus position of the focus probe is adjusted. Is.

[0010]

First, the principle of detecting the peeled state of the present invention will be described with reference to FIG. When a peeling condition occurs, there are gaps or thin air layers. 20 of FIG. 2 (a)
Is this release layer. The base 21 is the IC chip 22 to which it is adhered. When the ultrasonic wave is applied to the boundary portion of this layer, it is found that the echo reception signal A on the separation layer side and the echo reception signal B on the non-separation side have inverted or different phases (FIG. 2). (See (b)). Due to this phase inversion or difference, the echo reception signal at the boundary changes greatly. This is not related to the slight difference in gain or the shift of the focus position with respect to the echo reception signal.

FIGS. 2 (c) to 2 (f) show an example of the level of the echo reception signal when the separation layer boundary portion of the IC is measured. As shown by the arrow, a large dip appears in the echo reception signal corresponding to the boundary of the separated state. FIG. 6C shows the level of the echo reception signal when the gain is appropriate in the X direction (horizontal direction) of the display screen,
(D) is the level of a similar echo reception signal when the gain is set excessively. The figure (e) shows the level of the echo reception signal when the gain is proper in the Y direction (longitudinal direction) of the display screen, and (f) shows the level of the echo reception signal when the gain is set excessively. Is. Here, this drop (the echo reception signal at the position of the arrow) clearly appears even if the gain of the ultrasonic flaw detector is increased slightly or the focus position is slightly shifted.

The signal at the boundary of the separated state can be clearly captured by taking the second derivative of the echo reception signal. However, the drop portion (the position of the arrow) of the echo reception signal is noisy. It is also caused by. Therefore, in order to distinguish the drop in the noise part and the drop in the boundary part, smoothing processing is performed on the measurement data of the echo reception signal. As a result, the noise portion is removed, and the boundary line portion in the separated state can be separated from the noise and contour-displayed, and the portion can be clarified. Note that the above is also common to voids.

Therefore, by generating the contour data based on the data obtained by performing the smoothing process on the measurement data or the display data as described above, it is possible to contour-display the peeled region or the void portion. In the contour display, not only the peeling state and voids but also the outer shape of the structure are displayed according to the internal structure of the inspected part. When the gain or focus position of the ultrasonic flaw detector is significantly deviated, the contour does not sufficiently appear, and in such a case, it is obvious from the contour image. Therefore, even a person who is not an ultrasonic measurement expert may adjust the gain and the focus position so that the contour image becomes clear. As a result, even an unskilled person in ultrasonic measurement can easily inspect the peeled state and voids in the inspected article. In particular, it becomes easier to understand by displaying the cross-sectional image of the conventional C scope and then displaying the contour image here.

[0014]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a block diagram of an ultrasonic measuring apparatus to which an ultrasonic image inspection apparatus of the present invention is applied, FIG. 2 is an explanatory view of a principle of detecting a peeled state of the present invention, and FIG. FIG. 4 is a flowchart of a void inspection process, and FIG. 4 is an explanatory view of a cross-sectional image of a conventional C scope and a contour image according to the present invention for a chip portion of an IC. In FIG. 1, 20
Is an ultrasonic measurement device and has an ultrasonic flaw detection unit 6 to which the probe 4 is connected. The probe 4 is a focus type probe attached to an XYZ moving mechanism 5 which is a scanning mechanism.
Thus, the inspected component 1 such as an IC is scanned in the XY directions.
The height of the probe 4 with respect to the inspected component 1 can be set by moving the probe 4 in the Z direction, and the probe 4 is focused on a predetermined depth position to be inspected. During the inspection, the inspected component 1 is usually placed on the bottom of the water tank 2 or on the pedestal, and is immersed in the water 3 together with the probe 4.

The ultrasonic flaw detection section 6 is a measurement section which has a so-called pulser / receiver built-in, which transmits a transmission pulse signal to the probe 4 and receives an echo reception signal from the probe 4, and which is equipped with an oscilloscope or the like as necessary. The received signal is amplified or attenuated and sent to the peak detector 7.

The peak detector 7 produces an echo reception signal waveform at the gate portion set corresponding to the focus position of the probe 4, with respect to the waveform of the echo reception signal obtained by the ultrasonic flaw detector 6 and the probe 4. Extract and detect the peak value. Then, the analog voltage value corresponding to the peak level of the echo reception signal in the gate is
The A / D conversion circuit 8 performs A / D conversion for digitization, and sends it to the measurement data processing device 16. In addition, the gate is the probe 4 in the measurement data processing device 16.
The position is calculated according to the distance from the inspected component 1 (height in the Z direction), and the gate control signal corresponding to this position is sent from the measurement data processing device 16 and set.
The gate set by the peak detector 7 has a surface wave synchronous gate mode and a main synchronous gate mode.

The measurement data processing unit 16 includes a microprocessor (hereinafter referred to as MPU) 9, a keyboard (or an operation panel, and a keyboard including the operation panel) 10, an interface 12, an image memory 13, a main memory 14, and a display. 15 and the like, which are connected to each other by a bus 11. In addition, the XYZ moving mechanism 5, the peak detection unit 7, and the ultrasonic flaw detection unit 6 are also connected to the bus 11 via the interface 12, and the MPU
They are controlled by 9.

The MPU 9 includes a peak detecting section 7 (its A / D
The data is received from the conversion circuit 8), the data is temporarily stored in the main memory 14, the processing described later is executed on this data according to various processing programs stored in the memory, and the result is stored in the image memory 13. A process of storing and displaying the measurement result on the display 15 is performed. here,
The image smoothing processing program 14 is stored in the main memory 14.
a, an edge emphasis processing program 14b, an inspection area binarization processing program 14c, a peeling area ratio calculation / pass / fail judgment program 14d, etc. are stored, and a depth set value from the surface of the inspection surface input from the keyboard 10 or The measurement data such as the sound velocity of the inspected component and the data such as the measurement result are stored in the data storage area 14e.

The image smoothing processing program 14a causes the MP to be input by inputting a peeling inspection function key from the keyboard 10.
It is started by U9. FIG. 3 shows a processing flow of the peeling inspection processing program in this case. The MPU 9 executes this program by inputting a function key for peeling inspection. As a result, the measurement data stored in the main memory 14 is expanded into two-dimensional image data corresponding to the pixels on the display screen, and for the pixel of interest, for example, the average value of the nine pixels diagonally to the front, rear, left, and right is calculated and the Set to pixel value. Then, the target pixel is sequentially updated to calculate the average value,
An average value of all display pixels is calculated to generate display data in which the image is smoothed (step 100). Note that image smoothing is performed so that noise is not erroneously detected as an edge in the next edge enhancement process, and the average value is adopted by, for example, four pixels before and after, left and right, and five pixels of self. It may be present, and may be determined depending on the inspection target.

The edge enhancement processing program 14b is started after the processing of the image smoothing processing program 14a is completed (step 101). The MPU 9 performs so-called contour extraction processing by Laplacian on the display data smoothed by this execution, and performs edge enhancement.

The Laplacian is a so-called second derivative of the original data, and the function f (x, y) of each measurement data obtained corresponding to the display position on the screen (X, Y) is ▽ ² f in the x direction. In (x), the y direction becomes ▽ ² f (y). With these functions, display data is generated corresponding to the pixel positions on the screen and transferred to the image memory 13.

As described with reference to FIG. 2, at the boundary between the separation and the void, a large change appears in the measurement data due to the phase inversion or the phase difference of the reflected echo. By capturing this with the second derivative, this portion can be displayed as a contour. At this time, the frame of the IC chip also appears as a contour.

Therefore, when the gain adjustment is poor or the focusing is poor, a contour image on the IC chip side cannot be obtained sufficiently. When this contour image appears well, the contours of peeling and voids are often captured. Therefore, the gain and focus may be adjusted so that the outline image on the IC chip side can be sufficiently obtained. Such adjustment can be relatively easily performed by a non-expert if the structure and shape of the inspection object are known.

The inspection area binarization processing program 14c is
After the processing of the edge emphasizing processing program 14b is completed, it is activated by the function key input (step 102) of the quality judgment (step 103). When the keyboard is input, the MPU 9 receives the inspection area binarization processing program 14
Execute c. By this execution, first, with respect to the display data of the contour extraction, an inspection target area is set and the data is binarized. That is, first, the operator specifies the range to be inspected with the cursor (step 10).
3). Next, the range is read from the position of the cursor on the screen, a threshold value (threshold level) is set for this range, and the display data of the multi-tone data is converted into binarized display data (step 104). This is transferred to the image memory 13 and an edge is displayed on the screen of the display 13 (step 105). For example, since the chip area of the IC is the inspection area as the inspection area, this area is set in step 103. Further, here, in step 104, for example, the data that exceeds the threshold is set to "1", and the other data is binarized to "0".

FIG. 4A shows an image of the inspection portion contour-displayed in step 105.
(B) shows a conventional C scope image. The peeled area ratio calculation / pass / fail judgment program 14d is started after the processing of the inspection area binarization processing program 14c is completed (steps 106 and 107). By executing this, the MPU 9 causes the area S of the inner region surrounded by “1” to be S.
To calculate. Note that the peeling or void region is a region smaller than the entire area. Therefore, the small enclosed area side is selected as the exfoliation area. The area S of this region is calculated. Of course, the portion surrounded by the outer outline is not defined as the peeling area. The calculated area S is compared with the area SR set as a pass / fail judgment standard, and if it exceeds the area SR, it is judged to be defective (step 108). In the IC, for example, about 5 to 10% of the area of the chip is used as a comparison standard for acceptability.

As described above, in the embodiment, the inspection region is designated and the state of peeling or voids is detected by the binarization process, and the area is calculated to judge the quality, but it is simply displayed. The quality of the inspected part may be determined from the image displayed. In this case, it is easy to understand by displaying the conventional measurement image shown in FIG. 4B and then displaying the image shown in FIG. If the contour is unclear in the image of (a), the gain may be reset or the focus position may be adjusted and the inspection may be performed again. Further, the object to be inspected is not limited to the electronic component, and may be any article as long as it is an article inspecting for defects such as peeling and voids.

[0027]

As can be understood from the above description, according to the present invention, the contour data is generated based on the data obtained by performing the smoothing process on the measurement data or the display data, and the region in the peeling state is generated. Since the outlines of voids and voids can be displayed, the state of peeling and voids can be clearly displayed, and parts can be inspected without being affected by slight differences in the gain settings of the ultrasonic flaw detector and slight misalignment. You can easily. As a result, even an unskilled person can inspect the parts.

[Brief description of drawings]

FIG. 1 is a block diagram of an ultrasonic measurement device to which an ultrasonic image inspection device of the present invention is applied.

FIG. 2 is an explanatory diagram of a principle of detecting a peeled state according to the present invention.

FIG. 3 is a flowchart of a peeling or void inspection process.

FIG. 4 is an explanatory view of a cross-sectional image of a conventional C scope and a contour image according to the present invention with respect to a chip portion of an IC.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Inspected part, 2 ... Water tank, 4 ... Focus type ultrasonic probe (probe), 5 ... XYZ moving mechanism, 6 ... Ultrasonic flaw detection part, 7 ... Peak detection part, 8a ... A / D conversion circuit, 8b ...
Time measurement circuit, 9 ... Microprocessor (MPU), 1
0 ... Keyboard, 11 ... Bus, 13 ... Image memory, 14
... main memory, 14a ... image smoothing processing program,
14b ... Edge enhancement processing program, 14c ... Inspection area binarization processing program 14c, 14d ... Peeling area ratio calculation / pass / fail judgment program, 14e ... Data storage area, 16
… Measurement data processor.

Claims (3)

[Claims] 1. A focus type probe, and an ultrasonic flaw detector for driving the probe and receiving an echo reception signal from the probe to amplify or attenuate the echo reception signal to obtain a measurement signal. In an ultrasonic image inspection device which is set at a predetermined position inside an inspected article and displays a cross-sectional image of the inspected article according to the measurement signal, measurement of the inspected article obtained according to the measurement signal Smoothing processing means for performing smoothing processing on the data or display data; contour data generating means for performing second-order differentiation processing on the smoothed measurement data or display data to generate contour data; and the contour And a contour display unit for displaying a contour image according to data, wherein the amplification factor or the attenuation factor of the ultrasonic flaw detection unit can be externally adjusted. Video inspection devices. 2. The article to be inspected is an electronic component, the contour data generating means performs Laplacian processing, and when the contour image is not proper, the focus position of the probe or the amplification factor or attenuation factor. The ultrasonic image inspection apparatus according to claim 1, wherein is adjusted. 3. An ultrasonic image inspection apparatus having a focus type probe for ultrasonically measuring an inspected article and displaying a cross-sectional image, wherein smoothing processing is performed on measurement data or display data of the inspected article. Then, second-order differentiation processing is performed on the smoothed measurement data or display data to generate contour data, a contour image is displayed based on this contour data, and when the displayed contour image is not appropriate. An ultrasonic image inspection method comprising adjusting a gain of an echo reception signal of the article to be inspected or a focus position of the focus type probe.