JP2877061B2 - Coplanarity 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 coplanarity inspection apparatus, and more particularly to a coplanarity inspection apparatus for inspecting a height difference between bumps of an IC chip.

[0002]

2. Description of the Related Art As a conventional height inspection apparatus using a laser, there is a "method of inspecting the appearance of electronic parts" disclosed in Japanese Patent Application Laid-Open No. H4-1508.

FIG. 3 is a perspective view showing this conventional inspection apparatus, wherein 101 is a substrate, 102 is a lead of an electronic component 108 mounted on the substrate 101, 103 is a circuit pattern formed on the substrate 101, and 104 is a circuit pattern. A solder portion for bonding the lead 102 and the circuit pattern 103; 105, an xy-direction position detecting element such as PSD; 110, a laser device;
Reference numeral 1 denotes a mirror for scanning the laser spot light emitted from the laser device 110 in the xy directions.

Next, a description will be given of the height measurement by the conventional inspection apparatus.

While scanning the laser spot light emitted from the laser device 110 in the x-direction from the lead 102 to the solder portion 104, the laser light reflected at each of the reflection points A to H is applied to the position detecting element 105. Incident,
From the positions of the incident points ya to yh in the y direction, the height of the surface of the lead 102 or the solder portion 104 is detected, and the shape of the solder portion 104 is determined. At this time, by simultaneously detecting the positions of the incident points xa to xh in the x direction, the positions of the reflection points A to H in the x direction are detected, and the appropriateness of the detected position of the detected height is determined.

[0006]

The above-described conventional height inspection method using a laser has the drawback that the mechanism for performing laser scanning is complicated and the inspection time is long.

[0007]

SUMMARY OF THE INVENTION A coplanarity inspection apparatus according to the present invention includes a lighting device arranged around a substrate to be inspected to illuminate a slope of a bump, and a camera for imaging the substrate to be inspected and outputting analog image data. A / D conversion means for inputting analog image data and performing A / D conversion to output a grayscale image signal, and binarization for inputting a grayscale image signal and binarizing the bump portion having a large amount of reflected light to be "1" Means, and the binarized data binarized by the binarizing means are input, and the center of gravity of each label is calculated and calculated by a labeling process.
The bump height inspection range is determined based on the obtained center of gravity position. <br/> The inspection position calculating means matches the bump height inspection position obtained by the inspection position calculating means with the measurement position of the optical displacement measuring means. XY driving means for moving the inspection target substrate XY in such a way as to cause the bump height to be measured using an optical displacement measuring means , and coplanarity is calculated from the height measurement result at the bump height inspection position. A coplanarity calculation unit that performs the coplanarity calculation ,
Output means using the least error square method from the bump height data.
Low bump and high bump furthest from the plane.
It is characterized in that the difference between pumps is defined as coplanarity. light
The mechanical displacement measuring means is a laser displacement meter.
You. Bump height detection set by inspection position calculation means
The inspection range is the center of gravity of each label.
Bump height inspection range set by inspection position calculation means
It is characterized in that the enclosure is a designated area including the position of the center of gravity.

[0008]

Next, an embodiment of the present invention will be described with reference to the drawings.

FIG. 1 is a block diagram showing an embodiment of the present invention.

[0010] The coplanarity inspection apparatus shown in FIG.
Light up the slopes of. The camera 4 images the inspection target substrate 1 and outputs analog image data a. AD conversion means 5
Receives analog image data, performs AD conversion, and outputs gray image data b. The binarizing means 6 outputs the grayscale image data b
And outputs the binarized image data c at a predetermined binarization level so that only the bump slope having a large amount of reflected light becomes “1”. The inspection position calculation means 7 receives the binarized image data c, calculates the center of gravity of each label by a labeling process, and outputs bump height inspection position data d as a bump height inspection position. The XY stage driving means 8 inputs the bump height inspection position data d, drives the XY stage 10 so that the bump height inspection position coincides with the measurement position of the laser displacement meter 9, and outputs a positioning end signal e. The height measurement means 11 receives the positioning end signal e, measures the height of the bump by the laser displacement meter 9, and outputs the measurement end signal f and the bump height data g. The XY stage driving means 8 receives the measurement end signal f, measures the bump height for the number of labels, and outputs the all bump measurement end signal h after the measurement for all the labels. The coplanarity calculation means 12 sequentially inputs the bump height data g, and after inputting the all bump measurement end signal h, calculates the coplanarity and outputs the coplanarity i. Good / bad judgment means 1
No. 3 compares the coplanarity i with the preset maximum value of the coplanarity non-defective item, and determines that the coplanarity calculated from the coplanarity non-defective item maximum value is large, and that the coplanarity i is non-defective if the coplanarity is equal or smaller.

Hereinafter, specific detection examples will be described with reference to FIGS.
This will be described with reference to FIG. FIGS. 2A to 2D are diagrams illustrating the principle of the coplanarity inspection device according to the present invention. The illumination 2 is arranged around the inspection target substrate 1 such that the amount of light reflected from the slope portion of the bump 3 on the inspection target substrate 1 is largest and is reflected directly above. The camera 4 is the inspection target substrate 1
And outputs analog image data a. The AD converter 5 receives the analog image data, performs AD conversion, and outputs grayscale image data b. FIG. 2A is a pattern diagram of the grayscale image data b of the inspection target substrate 1. In FIG. 2A, the slope portion of the bump is a portion having a large density value. The binarizing means 6 receives the grayscale image data b, binarizes it at a predetermined binarization level so that only the bump slope portion having a large density value becomes "1", and outputs the binarized image data c. I do.
FIG. 2B is a pattern diagram of the binarized image data c, and the slope portion of the bump is the area of “1” after binarization. FIG.
In (b), since the amount of reflected light is small and the density value is small at the top of the substrate and the ball, the area becomes “0” after binarization. The inspection position calculation means 7 receives the binarized image data c, calculates the center of gravity of each label by a labeling process, and outputs bump height inspection position data d as a bump height inspection position. FIG. 2C shows the position of the center of gravity of each label calculated by the position inspection means 7. The XY stage driving means 8 inputs the bump height inspection position data d, drives the XY stage 10 so that the bump height inspection position coincides with the measurement position of the laser displacement meter 9, and outputs a positioning end signal e. The height measuring means 11 inputs the positioning end signal e, measures the bump height by the laser displacement meter 9, and outputs the measurement end signal f and the bump height data g.

As a means for measuring the bump height, as shown in FIG. 2D, an inspection range of a predetermined size is generated so that the barycentric coordinates of each label become the center, and the bump height measurement range is determined. When the bump height is measured at a preset pitch within the bump height measurement range and the maximum value of the measured bump height is used as the bump height data, the peak of the bump is located at a position slightly deviated from the center of gravity. However, a method of measuring the height of the bump is also conceivable.

The XY stage driving means 8 outputs a measurement end signal f
And repeat the bump height measurement for the number of labels,
After the measurement is completed for all labels, an all-bump measurement end signal h is output. The coplanarity calculating means 12 sequentially inputs the bump height data g, inputs the all bump measurement end signal h, calculates the coplanarity, and outputs the coplanarity i. As a method of calculating the coplanarity, for example, there is a method in which a plane is obtained from the height data of all bumps by the least error square method, and the difference between the lowest bump and the highest bump farthest from the plane is used as the coplanarity. Good / bad judgment means 1
3 is a comparison between the coplanarity i and the preset maximum value of the coplanarity non-defective product, and the coplanarity i calculated from the coplanarity non-defective maximum value is large;
If they are the same or smaller, they are determined to be good.

In the block diagram of FIG. 1, the camera and the laser displacement meter are fixed and the substrate to be inspected moves XY. However, the structure where the substrate to be inspected is fixed and the camera and the laser displacement meter move XY. Conceivable. Further, an optical scan type displacement measuring device other than the laser displacement meter can be used.

[0015]

According to the coplanarity inspection apparatus of the present invention, a bump on a substrate to be inspected is collectively imaged by a camera, a bump height inspection position is calculated from the imaged image, and only the calculated inspection position is determined using a laser displacement meter. The height can be measured and the coplanarity can be calculated, so that the inspection can be performed at low cost and at high speed without being affected by the displacement of the bump position.

[Brief description of the drawings]

FIG. 1 is a block diagram showing an embodiment of the present invention.

FIGS. 2A to 2D are diagrams for explaining the principle of the present invention.

FIG. 3 is a perspective view showing an example of the related art.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Inspection object board 2 Lighting 3 Bump 4 Camera 5 A / D conversion means 6 Binarization means 7 Inspection position calculation means 8 XY stage drive means 9 Laser displacement meter 10 XY stage 11 Height measurement means 12 Coplanarity calculation means 13 Good / bad judgment means 21 Inspection Control Board 22 Bump 23 Bump Slope 24 Label Center of Gravity 25 Bump Height Measurement Range

Claims (4)

(57) [Claims] 1. An illumination device arranged around a substrate to be inspected so as to illuminate a slope of a bump, a camera for imaging the substrate to be inspected and outputting analog image data, and performing AD conversion by inputting the analog image data. A / D conversion means for outputting a grayscale image signal, binarizing means for inputting the grayscale image signal and binarizing the bump portion having a large amount of reflected light to be "1", Inspection position calculation means for inputting the binarized data, calculating the center of gravity of each label by labeling processing, and determining a bump height inspection range based on the calculated center of gravity, and the inspection position calculation means XY driving means for moving the inspection target substrate XY so that the obtained height inspection position of the bump coincides with the measurement position of the optical displacement measuring means, and the optical displacement meter
A height measuring means for measuring the height of the bump by using the measuring means, compares the coplanarity calculating means for calculating the coplanarity from the height measurement result of the bump height inspection position, and said coplanarity and good judgment value The coplanarity calculating means, which has good / bad determining means
Is flattened by the least error square method from bump height data.
The lower bump and the higher bump furthest from the plane.
A coplanarity inspection apparatus characterized in that the difference between the steps is defined as coplanarity. 2. The coplanarity inspection device according to claim 1, wherein said optical displacement measuring means is a laser displacement meter. 3. The coplanarity inspection apparatus according to claim 1, wherein the bump height inspection range set by said inspection position calculation means is a center of gravity of each of said labels. 4. The coplanarity inspection apparatus according to claim 1, wherein a bump height inspection range set by said inspection position calculation means is a designated area including said center of gravity position.