JPH0578176B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (1) Technical Field of the Invention The present invention relates to an inspection apparatus for electronic components, for example, an apparatus for automatically inspecting defects in an integrated circuit (IC) die bonding assembly process.

(2) Technology background The IC assembly process includes chip separation (cutting the wafer into individual chips), die bonding (dying or attaching the chips to a package), and wire bonding (die attaching the chips to a package). These processes include stringing wires between the chip's electrodes and package leads) and sealing (sealing the package), and automation is progressing in each process. However, inspections after each process to increase IC reliability have not yet been automated and rely on visual inspection by workers.

(3) Conventional technology and problems Currently, the die bonding process is automated and high-speed processing is performed. However, post-processing inspections still rely on visual inspection by workers, which has drawbacks such as not being able to perform a 100% inspection (inspection of all ICs), and inspection standards differing depending on individual differences among workers. Furthermore, in die bonding, there is a problem in that if wire bonding is performed without the chip being completely attached to the die, the chip will break, resulting in the same result if a defective product is produced.

(4) Purpose of the Invention In view of the above-mentioned conventional problems, an object of the present invention is to provide an apparatus that automates the post-die bonding inspection that relies on visual inspection by an operator and enables high-speed 100% inspection. .

(5) Structure of the Invention According to the present invention, this object includes: an A/D converter that converts a signal from an imaging device into analog/digital; an image memory that stores the signal from the A/D converter; A first illumination device that performs vertical epi-illumination to image the IC chip position; a second illumination device that images the area around the IC chip from four sides of the IC chip; and an image obtained by the first illumination. a position detection circuit for detecting the position of the IC chip;
Based on the image obtained by the second illumination and the position of the IC chip, predetermined inspection areas corresponding to each of the outer peripheries of the IC chip were set in four directions around the IC chip, and the areas protruding around the IC chip within the inspection area were set. I C
It is characterized by comprising a mounting member inspection circuit that inspects the ratio of the inspection area of the chip mounting member to the whole, and a pass/fail determination circuit that automatically determines whether the die bonding condition is good or bad based on the output of the mounting member inspection circuit. This is achieved by providing a die bonding inspection device that achieves this.

(6) Examples of the invention Embodiments of the present invention will be explained in detail below with reference to the drawings.

Die bonding is a process of attaching an IC chip (also called die) 1 separated from a wafer to a die stage 3 of a package 2, as shown in FIG. First, a gold pellet 4 is placed on the die stage 3, and a chip 1 is rubbed onto it.
This causes eutectic formation of gold and silicon, and the chip 1 is fixed on the die stage 3. Note that the first
In the figure, 5 indicates a lead.

FIG. 2 is an enlarged sectional view of the die bonding portion of the package after die bonding. A portion of the eutectic gold-silicon adheres to the sides of the chip and forms a gold-silicon fillet 6. Fillet 6
Whether or not die bonding was successful can be determined based on the presence or absence of . Note that in FIG. 2, 7 indicates a lead.

3 and 4 are diagrams showing the method of inputting images of the IC chip and the gold-silicon fillet used in the present invention, and FIG. A lighting system is shown. In imaging, first the illumination 11, which is the first illumination device,
, and illuminate from directly above chip 1. If this image is captured by the TV camera 13 directly above, for example, the third
The image shown in Figure b is obtained. In Fig. 3, 15 is a half mirror, 16 is a lens, and 17 is a half mirror.
An IC chip image is shown.

FIG. 4a is a diagram of the illumination system for imaging the gold-silicon fillet 6, in which the second illumination device, the illumination 12, illuminates the IC chip 1 from four sides, and
When the TV camera 14 captures an image of the fillet, the fourth
The image shown in Figure b is obtained. In the figure, 18
indicates a fillet image.

The testing procedure of this device will be explained with reference to the block diagram of FIG. In the figure, S indicates the start of the test.

In the step indicated by a in FIG.
Turn on and input the image of IC chip 1. The image thus obtained is shown in FIG.

In step b shown in FIG. 5, the addresses of the four corners of IC chip 1 are determined from the image obtained in step a.

In step c in FIG. 5, the illumination 12 is turned on and an image of the gold silicon fillet 6 is input. An image of the gold silicon fillet 6 is shown in FIG.

In the step indicated by d in FIG. 5, the chip outer circumference (the outer circumference is shown by the dotted line in FIG. 7) of the image in step c is defined from the address obtained in step b.

In step e in FIG. 5, a predetermined inspection area (region, indicated by reference numeral A in FIG. 8) is set from the outer periphery of the chip.

In step f in Fig. 5, the inspection area A
The fillet signals within the slice are counted, and if the value is greater than or equal to a predetermined value (slice level), it is determined that there is a fillet.

There is no test for counting, that is, high level, in the direction indicated by the arrow in Figure 9, 1, 0.
Check the level of and count how many 1s there are.
Scan to see how many 1's there are, obtain a count signal, slice it at a certain level, and test how far the fillet signal is. An offset is provided for the slice level in consideration of noise and the like.

Finally, in step g in FIG. 5, the percentage of the entire inspection area in which the fillet 6 is present is determined, and if the value is greater than or equal to a predetermined value (inspection standard), it is determined to be a good product, and if it is less than a predetermined value, it is determined to be a defective product.

Next, the structure and operation of the apparatus of the present invention will be explained with reference to the block diagram of FIG.

Turn on the lighting device 11 and connect the IC1 to the TV camera 13
Take an image with The video signal passes through a TV camera drive circuit 22, is analog-to-digital converted by an A/D converter 23, and is stored in an image memory 24. Position detection circuit 2 from data in image memory 24
Find the IC chip corner address in step 5. The above corresponds to steps a to b in FIG.

Next, the illumination device 12 is turned on, and the IC 1 is imaged with the TV camera 13. The video signal is similarly stored in the image memory 24, and a fillet inspection circuit 26 inspects the fillet from the data in the image memory 24. The above corresponds to steps c to f in FIG.

Further, a good/bad judgment circuit 27 judges whether the die bonding is good or bad. This corresponds to step g in FIG.

Note that the control device 21 is for controlling the entire inspection device. That is, the control device 21
is used to switch the illumination devices 11 and 12, and instruct the image memory 24, position detection circuit 25, fillet inspection circuit 26, and pass/fail judgment circuit 27.

The embodiments of the present invention have been described above, taking as an example the inspection after die bonding processing using eutectic of gold and silicon. Die bonding using other conductive resins or adhesives can be similarly tested.

(7) Effects of the Invention As described in detail above, according to the present invention, an inspection device for an IC chip or the like consisting of an imaging device, a lighting device, an A/D converter, an image memory, and an inspection circuit can be used to test a sample, for example, an IC chip. How is the installation done?
The shape of the mounting member allows for automatic inspection, and also allows for 100% inspection, which is highly effective in improving the reliability of semiconductor devices.

[Brief explanation of the drawing]

Fig. 1 is an exploded perspective view for explaining die bonding, Fig. 2 is an enlarged sectional view of the die bonding part, Fig. 3 is a diagram showing an IC chip image input method,
FIG. 4 is a diagram showing a gold silicon fillet image input method, FIG. 5 is a diagram showing an inspection procedure of the apparatus of the present invention,
Figure 6 is a diagram schematically showing an IC chip image, Figure 7
8 is a diagram schematically showing a fillet image, FIG. 8 is a diagram showing an inspection area, FIG. 9 is a diagram showing a fillet counting principle, and FIG. 10 is a block diagram of the configuration of a die attaching inspection apparatus. 1...IC chip, 2...package, 3...
Dice stage, 4... Gold pellet, 5... Lead, 6... Gold silicon fillet, 11, 12
...Lighting, 13,14...TV camera, 15...
Half mirror, 16... Lens, 17... IC chip image, 18... Fillet image, 21... Control circuit, 22... TV camera drive circuit, 23...
A/D converter, 24...Image memory, 25...Position detection circuit, 26...Gold silicon fillet detection circuit, 27...Good, defective determination circuit, A...Inspection area, S...Inspection disclosure, a...IC chip image input, b...IC chip corner detection, c...gold silicon fillet image input, d...IC chip outer periphery detection, e...inspection area setting, f...fillet signal counting within the inspection area, g...Good, bad judgment,
...Counting direction, ...Slice level.

Claims (1)

[Claims] 1. An A/D converter that converts signals from an imaging device into analog/digital, an image memory that stores signals from the A/D converter, and a vertical epi-illumination device for imaging the IC chip position. A first illumination device that illuminates, and from four sides of the IC chip,
a second illumination device for capturing an image around the IC chip; a position detection circuit for detecting the position of the IC chip from the image produced by the first illumination; and a position detection circuit for detecting the position of the IC chip from the image produced by the second illumination A predetermined inspection area corresponding to each of the outer periphery of the IC chip is set in four directions around the IC chip from the position, and the area protruding around the IC chip within the inspection area is
It is equipped with a mounting member inspection circuit that inspects the ratio of the IC chip mounting member to the entire inspection area, and a pass/fail judgment circuit that automatically determines whether the die bonding condition is good or bad based on the output of the mounting member inspection circuit. Features of die bonding inspection equipment.