JPH04359447A - Soldering-junction inspecting apparatus for semiconductor device - Google Patents

Abstract

PURPOSE:To make it possible to inspect a soldering junction at a central part of a chip easily at a high speed with high accuracy with regard to an inspecting apparatus for a soldering junction of a semiconductor device. CONSTITUTION:A soldering-junction inspecting apparatus is used for a semiconductor device having a semiconductor chip 1 and a substrate 3, which are bonded together through soldering bumps 5 and 7 formed on the semiconductor chip 1. The soldering-junction inspecting apparatus includes an X-ray source 12 for irradiating a soldering junction 2, and an X-ray detecting means 14 for detecting an X-ray that has been transmitted through the soldering junction 2. Moreover, the soldering-junction inspecting apparatus includes a multi-valued shading data forming means 25 for generating multi-valued shading data on the detected X-ray from the output of the X-ray detecting means 14, and a soldering-junction abnormality judging means 30 for judging whether or not there is a change in shading in a given region of the soldering junction by using the multi-valued shading data.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a solder joint inspection apparatus for semiconductor devices, and more particularly to an inspection apparatus used for automatic inspection of surface mount components after a soldering process. 2. Description of the Related Art Recently, with the miniaturization of electronic devices, the packaging density of printed circuit boards constituting semiconductor devices has increased. In circuit systems for large computers, in order to shorten the wiring length between LSIs and improve signal propagation speed, it is necessary to accommodate the increasing number of LSI input terminals within the same chip size. Flip chips are attracting attention in response to these demands.

[0002] In the flip chip, ball-shaped solder made of Pn or Sn is previously provided on the electrode pads of an LSI chip via via metal, and all the electrodes are connected to the board at once by placing it on the board and melting the solder. It is something to do. Flip chips are superior in terms of high-density packaging, high reliability, and high productivity, and can have a much smaller mounting area than conventional chip components. However, it is necessary to inspect the solder joints after the chip is mounted on the board, but in the case of flip chips, it is difficult to inspect the solder joints using conventional visual or optical inspections. There are many.

0003

2. Description of the Related Art FIG. 7 shows an example of a flip-chip semiconductor device, in which (A) a silicon chip 1 is connected to a solder joint 2.
(B) is a perspective view showing the mounting on the board 3 by
(C) is an enlarged view showing the state before soldering, and (C) is an enlarged view showing the state after soldering. As shown in (B), ball-shaped solder bumps 5 are provided on the thin film electrode 4 of the silicon chip 1 by vapor deposition or the like, while ball-shaped solder bumps 7 are provided on the electrode 6 of the substrate 3 as well. It will be done. The solder bumps 5 of the silicon chip 1 and the solder bumps 7 of the substrate 3 are arranged at corresponding positions, and the silicon chip 1 is placed on the substrate 3. Then, when the substrate 3 on which the silicon chip 1 is mounted is heated, the solder bumps 5 and 7 melt and join together, forming a solder joint (footprint) 2, as shown in (C). Since surface tension is generated in the molten solder bumps 5, 7, the positions of the upper and lower solder bumps 5, 7 are automatically aligned, and a monolithic spherical or rounded cylindrical solder joint 2 is obtained. It will be done. However, in some cases, defective solder joints 2 are formed.

FIG. 8 is a diagram showing an example of a solder joint 2. As shown in FIG. (A) to (C) show normal solder joints 2, and (D
) to (G) show defective and abnormal solder joints 2. Here, the solder joints 2 (D) to (G) are respectively referred to as unfused, toppling type, reverse topping type, and elongated. In addition, there may be a positional shift where the solder joint part 2 falls diagonally, a void, etc.

[0005]

SUMMARY OF THE INVENTION Therefore, it is necessary to inspect the solder joints 2 after mounting the silicon chip 1 on the substrate 3. Conventional flip chip solder joint 2
Inspections have relied primarily on visual inspection using a microscope. However, in visual inspection, although it is possible to see the solder joints 2 located at the periphery of the silicon chip 1, it is difficult to see the solder joints 2 located at the center of the silicon chip 1. Although it is also possible to observe the reflected image of the solder joint 2 using a mirror, it is still difficult to inspect the solder joint 2 located at the center of the silicon chip 1.

Another test for flip chip solder joints 2 is to perform an electrical continuity test. However, many of the products to be inspected include complex logic, so when conducting an electrical continuity test, it is necessary to perform a tedious test that matches the logic of the product, which is extremely time-consuming. there were.

[0007] Furthermore, in order to inspect the solder joints 2 located at the center of the silicon chip 1, it is conceivable to irradiate the surface of the silicon chip 1 with X-rays and see through all the solder joints 2. . However, with conventional X-ray technology,
Forming a grayscale image on an X-ray photograph or display,
Abnormalities are determined by visually observing the grayscale image and based on the difference in grayscale. In this case as well, the obtained grayscale image has a fine structure, and it is difficult and time-consuming to recognize the object to be inspected from such a grayscale image. Additionally, although there are techniques such as CT scanning, it is difficult to use such techniques directly for inspecting solder joints.

An object of the present invention is to provide a solder joint inspection device for a semiconductor device that enables inspection of the solder joint located at the center of a chip, and that enables simple, high-speed, and highly accurate inspection. That's true.

[0009]

[Means for Solving the Problems] A solder joint inspection device for a semiconductor device according to the present invention includes an X-ray beam that irradiates a solder joint.
a radiation source, an X-ray detection means for detecting the X-rays transmitted through the solder joint, and a multi-value gradation data forming means for forming multi-value gradation data of the detected X-rays from the output of the X-ray detection means; The present invention is characterized by comprising a solder joint abnormality determining means for determining whether or not there is a portion where the density changes within a predetermined region of the solder joint based on the multivalued gray data.

A solder joint inspection device for a semiconductor device according to another aspect of the present invention includes two X-ray sources that can irradiate from above and below the solder joint; two X-ray detection means each capable of detecting the X-rays transmitted through the solder joint, and a first gray-scale data forming means for forming gray-scale data of the detected X-rays from the output of one of the X-ray detection means. , by comparing the second gradation data forming means for forming gradation data of detected X-rays from the output of the other X-ray detection means with the gradation data formed by the first and second gradation data forming means. The present invention is characterized by comprising a solder joint abnormality determination means for determining a solder joint abnormality.

[0011] Furthermore, an apparatus for inspecting a solder joint portion of a semiconductor device according to another aspect of the present invention includes
a radiation source, an X-ray detection means for detecting X-rays transmitted through the solder joint, and a gray-scale data forming means for forming gray-scale data of a profile passing through at least the center of the solder bump or its vicinity from the output of the X-ray detection means. , a solder joint abnormality determining means for determining a second-order differential of the density data of the profile and determining from the second-order differential whether or not the solder bump is abnormal.

0012

[Function] The above-described features of the present invention include an X-ray source, an X-ray detection means, a grayscale data forming means, and a solder joint abnormality determining means. The method of forming shading data and the corresponding determination of solder joint abnormalities each have detailed characteristics, but in any case, solder joints can be determined from shading data formed by transmitting the solder joint with X-rays. Abnormalities can be automatically determined by a computer.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a diagram showing the principle of the first feature of the present invention, and the upper row shows the step of irradiating the solder joint 2 with X-rays from above. A solder joint 2 is formed between the electrodes 4 and 6, and corresponds to one of the solder joints 2 of the flip-chip bonded semiconductor device shown in FIG. Solder joint 2
The solder bumps 5 and 7 of the silicon chip 1 and the substrate 3 are melted and integrated.

[0014] X-rays are irradiated from above each solder joint 2, and the X-rays transmitted through each solder joint 2 are usually formed as a grayscale image. In the present invention, the X-rays transmitted through each solder joint 2 are detected as numerical values for each minute section of each solder joint 2, providing grayscale data along the entire area of each solder joint 2. The solder contains components that easily absorb X-rays (hardly transmits X-rays) such as Pn, and the solder
Furthermore, the silicon chip 1 and the substrate 3 are made of a component that absorbs less X-rays than solder. Therefore, even if the electrodes 4 and 6, as well as the silicon chip 1 and substrate 3 are irradiated with X-rays at the same time, these do not appear as changes in the density of the transmitted X-rays as much as the solder joint 2.

Although the density data of the transmitted X-rays obtained in this manner can be used directly, it is preferable to log-convert the density data and use it as data corresponding to the thickness t. Generally, the amount of attenuation of X-rays when an object is irradiated with X-rays is expressed by the following formula. I=I0exp(-μt)
(1) Here, I0 is the incident X-ray dose, I is the transmitted X-ray dose, μ is the absorption coefficient, and t is the thickness of the object. Here, assuming that the absorption coefficient of continuous X-rays is constant, (1
) is converted into log, the following equation for the thickness t of the object is obtained: By substituting the detected amount of transmitted X-rays into this equation, the thickness t can be determined. t=-(1/μ)In(I/I0)
(2)

The middle part of FIG. 2 shows the density data of the transmitted X-rays of the solder joint 2 which has been log-converted in this manner. This shading data is the thickness t of each minute section of the solder joint 2.
It shows a profile proportional to , and the amount of transmitted X-rays is low in the central portion where the thickness t is large, and the amount of transmitted X-rays increases toward the outer periphery.

Next, the density data of the transmitted X-rays is multivalued. As shown in the lower part of FIG. 2, when the slice levels of the density of the transmitted X-ray dose are determined and the data of each level is plotted and imaged, a concentric striped pattern is created. This concentric striped pattern is essentially contour lines of light and shade levels.

Next, an abnormality in the solder joint 2 is determined from the multivalued gradation data of the transmitted X-rays obtained in this manner. Examples of abnormal solder joints 2 are shown in FIGS. 8D to 8G, and include unfused solder joints, cracked solder joints, reverse bent shapes, elongation, misalignment, voids, and the like. These abnormal products have a constricted outer circumferential shape, and compared to the normal products shown in FIGS. There is. Therefore, such a portion with a small wall thickness t appears in the multivalued gray data and can be easily determined to be abnormal.

FIG. 2 shows an example of a normal solder joint 2 and its multilevel gradation data, in which the striped pattern and contour lines are mostly formed outside the cylindrical region connecting the electrodes 4 and 6. FIG. 3 shows an example of the abnormal solder joint 2 and its multivalued gradation data, in which a part of the striped pattern and contour lines are formed inside the cylindrical region connecting the electrodes 4 and 6. Therefore, for example, if there is a striped pattern or contour lines within a circle equal to the area of the electrodes 4 and 6, it can be determined that there is an abnormality. In fact, a circle smaller than the electrodes 4 and 6, that is, a circle with a predetermined radius from the center of the solder joint 2, can be used as a reference.

FIG. 4 is a diagram showing a first embodiment of the present invention. A moving stage 10 supports a semiconductor device in which a silicon chip 1 is mounted on a substrate 3 by a solder joint 2. The moving stage 10 is controlled by a stage controller 11 including an actuator such as a motor, and is movable in the X and Y directions within one plane. An X-ray source 12 is arranged above the silicon chip 1, and an X-ray fluorescent screen 13 and a line sensor 14 are arranged below the substrate 3. Further, an imaging lens 8 is provided between the X-ray fluorescent screen 13 and the line sensor 14.
5 has been inserted. The X-ray source 12 irradiates the solder joint 2, and the X-rays transmitted through the solder joint 2 are sent to the X-ray fluorescent screen 13.
At this time, the X-ray fluorescent screen 13 emits light according to the amount of transmitted X-rays. The line sensor 14 detects the amount of X-rays transmitted through the solder joint 2, converts the fluorescence of the X-ray fluorescent screen 13 into an electrical signal, and connects the A/D converter 15 and the image signal input means 16.
send to The line sensor 14 is composed of, for example, a CCD in which a plurality of light-to-electric conversion elements are arranged in a row, and the solder joint 2
The amount of transmitted X-rays in a section corresponding to one row of a plurality of minute two-dimensional sections is detected. The solder joint 2 is the line sensor 14
By sending the moving stage 10 across the
All sections of the solder joint 2 are detected.

The solder joint inspection apparatus of the present invention includes a computer, that is, a CPU 17, and the formation of multivalued gray data and the determination of abnormalities in the solder joint 2 are carried out by the computer. The CPU 17 is connected to an image signal input means 16, a memory 18, and an I/O port 19 via a bus. Stage controller 11 is controlled via I/O port 19.

FIG. 5 is a flowchart of inspection of solder joints carried out with the apparatus of FIG. The X-rays irradiated from the X-ray source 12 pass through the solder joint 2 and pass through the X-ray fluorescent screen 1.
3 and is detected by the line sensor 14 (step 2
1). The output signal of the line sensor 14 is A/D converted (
Step 22), it is captured as a grayscale image signal and stored in the memory 18 (Step 23). This grayscale image signal is log-converted (step 24), multivalued at a specific slice level, and stored in the memory 18 as multivalued grayscale data (step 25).

On the other hand, the computer controls the stage controller 11 of the moving stage 10 so that the X-rays are irradiated almost perpendicularly to the center of each solder joint 2 (step 26), and the amount of stage movement is controlled by the computer. It is always input (step 27). Therefore, the position of the center of the bump (solder joint 2) is determined based on the multivalued gray data (step 28). An inspection range is determined with respect to this center (step 29), and a circle having a predetermined radius from the center of the solder joint 2 is set. Next, it is determined whether a striped pattern exists within this inspection range (step 30).
. If yes, it is determined to be normal (step 31), and if no, it is determined to be abnormal (step 32).

FIG. 6 is a schematic diagram showing this testing procedure. A plurality of silicon chips 1 are provided on the substrate 3,
The moving stage 10 moves while sequentially selecting the silicon chip 1 and the solder joints 2 therein. The location of the center of the bump is determined for each solder joint 2. The inspection range S is set as an area within a circle with a predetermined radius from the center of the solder joint 2. Finally, it is determined whether a striped pattern exists within this inspection range S.

FIG. 9 shows an embodiment according to the second feature of the present invention, which includes two X-ray sources 12a and 12b that can irradiate from above and below the solder joint 2, and the two X-ray sources 12a and 12b. Source 1
Two X-ray detection means 44a each capable of detecting X-rays irradiated from 2a and 12b and transmitted through the solder joint 2
, 44b. In this embodiment, the X-ray detection means 44a, 44b consist of an X-ray image intensifier.

The upper X-ray source 12a is located approximately on the same line as the lower X-ray detection means 44a, and the lower X-ray source 12b is located approximately on the same line as the upper X-ray detection means 44b. It has become. These two sets of detection devices are intended to irradiate the same solder joint 2 with X-rays from above and below and compare the results to inspect for abnormalities.

In FIG. 9, each X-ray detection means 44a, 4
The output signals of 4b are sent to A/D converters 15a and 15, respectively.
b and are stored as first and second grayscale data in the memories 18a and 18b via the image signal input means 16a and 16b. In this example, a computer, namely C
The PU 17 determines whether the solder joint 2 is abnormal by comparing the first and second shading data. Also,
Stage controller (SC) 11 has I/O port 19
controlled via.

In this embodiment, these two sets of detection devices are arranged a predetermined distance apart in the direction of movement of the semiconductor device supported on the movement stage 10. Once the solder joint 2, which is one set of detection devices 12b and 44b, is detected,
The semiconductor device is moved and the other set of detection devices 12,
The solder joint 2 is detected at 44a. A delay circuit 45 is inserted in the signal path of the X-ray detection means 44b that first generates the detection signal, and holds the detection signal of the X-ray detection means 44b for a time corresponding to the moving time of the solder joint 2. , both X-ray detection means 44a, 44b
are output synchronously.

FIG. 10 is a diagram illustrating problems when X-rays are irradiated from one side. (A) shows an example of an abnormal solder joint 2, in which one electrode 4 side is tapered. (B) shows an example of a normal solder joint 2. The neck part of the solder joint 2 in (A) is locally constricted, but when considering the overall thickness distribution, the thickness of the solder joint 2 in (A) and (B) Since the variation in the density is relatively small, the variation factor is less likely to appear in the density data obtained when X-rays are irradiated from one side. (A)
It becomes difficult to determine that the solder joint 2 is abnormal.

Therefore, in the present invention, two X-ray sources 12a,
12b irradiates the solder joint 2 with X-rays from above and below, and the first shading data and the second shading data are compared based on the outputs from the two X-ray detection means 44a and 44b. It is something.

Referring to FIG. 11, when X-rays are irradiated from above to the solder joint 2 as shown in FIG. When the section 2 is irradiated with X-rays from below, gradation data having a characteristic as shown by Q is obtained. It was found that there are considerable differences in the characteristics of P and Q. Therefore, P
By determining the difference between the characteristics of

[0032] When the solder joint 2 is irradiated with X-rays from above and below, such a difference in density data occurs because the closer the distance from the X-ray source to the object is, the larger the shadow in the X-ray fluoroscopic image becomes. This is because the longer the distance from the X-ray source to the object, the smaller the shadow in the X-ray fluoroscopic image. (Especially, this tendency increases when microfocus X-rays are used and the magnification is large.) Therefore, according to the second feature of the present invention, although the overall shape is relatively good, the vertical asymmetric This is effective for detecting abnormalities in solder joints 2 that have serious defects. In this case, there is no need to perform multi-value conversion as in the case of the first feature of the present invention, so the configuration becomes even simpler.

FIGS. 12 and 13 are flowcharts of an inspection that combines the first and second features of the present invention. In steps 51 to 55, the first test shown in FIGS. 1 to 5 is performed based on the output of one set of X-ray detection means 44b. If the answer is YES in step 55, it is determined that there is an abnormality, and the defect is dealt with in step 56. If no in step 55, (A
). Similarly, in steps 57 to 60, determinations are made based on the first inspection. If YES in step 60, it is determined that there is an abnormality, and the defect is dealt with in step 61. If the answer in step 60 is NO, the process proceeds to (A).

In FIG. 13, in step 62 the same pad is recognized, in step 63 pattern matching of the gray scale image data from the outputs of the respective X-ray detection means 44a and 44b is performed, and in step 64 both gray scale image data are matched. Make a deduction. Then, in step 65, the subtraction gray image data is binarized at a specific slice level, the binarized area is calculated in step 65, and it is determined in step 66 whether the binarized area is smaller than a predetermined value β. . If no, defect processing is performed in step 68, and if yes, normal processing is performed in step 69.

FIG. 14 shows a second embodiment according to the second feature of the invention.
This is an example. Similar to the embodiment of FIG. 9, X-ray sources 12a and 12b are provided on the upper and lower sides of the solder joint 2, respectively.
And X-ray detection means 44a, 44b are arranged. In this embodiment, the set of the X-ray source 12a and the X-ray detection means 44a and the set of the X-ray source 12b and the X-ray detection means 44b are arranged diagonally in a cross-crossing relationship, and at the same time are connected by the same solder. Section 2 is inspected from above and below. In this case as well, similarly to the embodiment of FIG. 9, defects in the solder joint 2 can be inspected by comparing the output data from the two X-ray detection means 44a and 44b.

FIG. 15 shows an embodiment according to the third feature of the invention. In this embodiment as well, the moving stage 10 supports a semiconductor device in which a silicon chip 1 is mounted on a substrate 3 via a solder joint 2. The moving stage 10 is controlled by a stage controller 11. An X-ray source 12 is arranged above the silicon chip 1, and an X-ray detection means consisting of an X-ray image intensifier 45 and a television camera 46 is arranged below the substrate 3.

In this embodiment as well, the determination of abnormality in the solder joint 2 is carried out by a computer. The CPU 17 is connected to the outputs of the A/D conversion circuit 15, memory 18, I/O port 19, display, etc. via a bus. Furthermore, logarithmic conversion means 48, quadratic differentiation means 49, defect detection means 50, etc. are provided. These logarithmic conversion means 48,
The second-order differentiating means 49 and the defect detecting means 50 are provided as functional means implemented by the CPU 17 or as circuit means controlled by the CPU 17.

FIG. 16 is a flowchart for inspecting the solder joint 2. In step 71, X-ray fluoroscopy is performed, in step 72, the center position of the bump is detected, and in step 73
Extract one line profile in step 74.
Perform logarithmic transformation (log transformation). The procedure up to this point is almost the same as that for obtaining the X-ray grayscale image data shown in the middle part of FIG. However, in FIG. 1, the X-ray grayscale image data was obtained for the entire solder joint 2, but in this embodiment, it is sufficient to perform the data for one line passing through the center of the solder joint 2 or its vicinity.

Next, in step 75, the second derivative of the profile of the solder joint 2 (one line of X-ray density image data) is calculated. As shown in FIGS. 17 and 18, the profile of the solder joint 2 is obtained as a function f of the distance (x) along the line crossing the solder joint 2,
The second derivative f'' can then be calculated. Then, in step 76, positive/negative continuity can be detected, and in step 77, defect detection can be performed. Note that in this case, the lookup table in step 78 is used. be able to.

FIG. 17 shows the characteristics of the profile f and its second derivative t'' when inspecting a normal solder joint 2 that is bulged in a barrel shape, and FIG. The characteristics of the profile f and its second-order differential f'' are shown when inspecting the profile f and its second-order differential f''. In the profile f of the normal solder joint 2 shown in FIG. 17, there is a downwardly convex curve at a position
The second derivative f'' has a waveform that suddenly falls from a positive value.On the other hand, in the profile f of the abnormal solder joint 2 shown in FIG.
becomes an upwardly convex curve, and its second-order derivative f'' becomes a waveform that falls suddenly toward the value of zero.In this way,
Depending on whether the solder joint 2 is constricted or not, the second derivative f'' of the profile f of the solder joint 2 exhibits a clear contrast, and it can therefore be determined whether it is normal or abnormal.

When actually determining abnormality, it is preferable to adopt the determination method shown in FIG. 19. In Figure 19 (
A) shows that the continuity of the positive and negative values of the numerical values in each minute interval plotting the second derivative f'' is detected. By having a predetermined number of consecutive positive or negative numerical values, the trend shown in Fig. 17 is detected. or the trend shown in Figure 18.Also, (B
) determines whether the value is positive or negative by determining a certain threshold value and calculating or integrating the sum up to that threshold value. By adopting such a method, the accuracy of judgment can be improved.

FIG. 20 shows a second embodiment according to the third aspect of the invention.
This is an example. In this embodiment, the configuration of the X-ray detection means is different from that in FIG. 15. This X-ray detection means is
It includes an X-ray fluorescent screen 83 and a line sensor 84 similar to the line fluorescent screen 13 and line sensor 14, and further includes an X-ray fluorescent screen 8
An imaging lens 85 is inserted between the line sensor 84 and the line sensor 84 .

[0043]

As described above, the solder joint inspection device for semiconductor devices according to the present invention includes an X-ray source, an X-ray detection means, a grayscale data forming means, and a solder joint abnormality determining means. With this configuration, abnormalities in solder joints can be automatically determined from the shading data created by transmitting X-rays through the solder joints, and even solder joints located in the center of the chip can be inspected. is possible.

[Brief explanation of drawings]

FIG. 1 is a diagram explaining the principle of the present invention.

FIG. 2 is a diagram showing a normal solder joint and its multivalued gradation data.

FIG. 3 is a diagram showing an abnormal solder joint and its multivalued shading data.

FIG. 4 is a diagram showing a first embodiment of the present invention.

FIG. 5 is a diagram showing a flowchart for inspecting solder joints.

FIG. 6 is a schematic diagram showing an inspection procedure.

FIG. 7 is a diagram showing a flip-chip semiconductor device;
(A) is a perspective view of the completed flip chip, (B) is a partial enlarged view before bonding, and (C) is a partial enlarged view after bonding.

FIG. 8 is a diagram showing examples of solder joints, in which (A) to (C) show normal solder joints, and (D) to (G)
FIG. 3 shows a defective solder joint.

FIG. 9 shows an embodiment according to the second aspect of the invention.

FIG. 10 is a diagram illustrating problems when X-rays are irradiated from one side.

FIG. 11 is a diagram illustrating a case where X-rays are irradiated from above and below.

FIG. 12 is a diagram showing the first half of a flowchart for inspecting solder joints.

FIG. 13 is a diagram showing the second half of a flowchart for inspecting solder joints.

FIG. 14 shows a second embodiment according to the second feature of the invention.

FIG. 15 shows an embodiment according to the third aspect of the invention.

FIG. 16 is a diagram showing a flowchart of inspecting a solder joint.

FIG. 17 is a diagram illustrating judgment when the test using second-order differentiation is normal.

FIG. 18 is a diagram illustrating judgment when an abnormality occurs in an examination using second-order differentiation.

FIG. 19 is a diagram showing an example of judgment in an inspection using second-order differentiation, where (A) is a diagram showing an example of detecting positive and negative continuity, and (B) is a diagram showing the calculation of the sum up to the threshold value. FIG.

FIG. 20 shows a second embodiment according to the third feature of the invention.

[Explanation of symbols]

1...Silicon chip 2...Solder joint 3...Substrate 4, 6...electrode 5, 7...Solder bump 10...Movement stage 12...X-ray source 12a, 12b...X-ray source 14...Line sensor 44a, 44b...X-ray detection means 45...Image intensifier

Claims (7)

[Claims] 1. A solder joint inspection apparatus for a semiconductor device in which a semiconductor chip (1) provided with solder bumps (5, 7) and a substrate (3) are joined by fusion of the solder bumps, the solder joint part (2) being ) is an X-ray source that irradiates (
12), an X-ray detection means (14) for detecting the X-rays transmitted through the solder joint (2), and a multi-value converter for forming multi-value gray scale data of the detected X-rays from the output of the X-ray detecting means. The solder joint abnormality determining means (30) is equipped with a shading data forming means (25) and a solder joint abnormality determining means (30) for determining whether there is a part where the shading changes in a predetermined area of the solder joint from the multivalued shading data. Semiconductor device solder joint inspection equipment. 2. The multilevel grayscale data is formed in a concentric striped pattern connecting transmitted X-ray doses of the same level, and the solder joint abnormality determination means detects a pattern within a circle with a predetermined radius from the center of the solder joint. 2. The solder joint inspection device for a semiconductor device according to claim 1, wherein the inspection device determines whether or not there is a striped pattern on the solder joint portion of a semiconductor device. 3. A solder joint inspection device for a semiconductor device in which a semiconductor chip (1) provided with solder bumps (5, 7) and a substrate (3) are joined by fusion of the solder bumps, the solder joint part (2) being ) two X-ray sources (12a, 12b) capable of irradiating from above and below;
Two X-ray detection means (44a, 44b) each capable of detecting X-rays emitted from the two X-ray sources and transmitted through the solder joint (2), and detection from the output of one X-ray detection means. a first grayscale data forming means (54) for forming grayscale data of X-rays; a second grayscale data forming means (59) for forming grayscale data of detected X-rays from the output of the other X-ray detection means; solder joint abnormality determination means (
67) A solder joint inspection device for a semiconductor device, comprising: 4. A semiconductor device is supported movably in a predetermined direction, and includes a set of one of the two X-ray sources and a corresponding one of the X-ray detection means, and a set of the other X-ray source and the corresponding X-ray detection means. A corresponding set of X-ray detection means and the other X-ray detection means are arranged a predetermined distance apart in the predetermined direction, and further output a detected value of the transmitted X-rays of the solder bump where one of the X-ray detection means is located, and When the device moves in the predetermined direction, after a travel time for the solder bump to reach the other X-ray detection means from the one X-ray detection means, the other X-ray detection means detects the transmitted X-rays of the solder bump. The apparatus is configured to output a detected value, and includes a holding means for holding and outputting the detected value of the one X-ray detecting means for a time corresponding to the travel time,
4. The solder joint inspection apparatus for a semiconductor device according to claim 3, wherein the detection values of the one and the other X-ray detection means are outputted in synchronization. 5. A solder joint inspection apparatus for a semiconductor device in which a semiconductor chip (1) provided with solder bumps (5, 7) and a substrate (3) are joined by fusion of the solder bumps, the solder joint part (2) being ) is an X-ray source that irradiates (
12), an X-ray detection means (45) for detecting X-rays transmitted through the solder joint (2), and forming shading data of a profile passing through at least the center of the solder bump or its vicinity from the output of the X-ray detection means. A semiconductor device comprising: grayscale data forming means (48) for determining the density data of the profile; and solder joint abnormality determining means (50) for calculating the second derivative of the grayscale data of the profile and determining from the second derivative whether or not the solder bump is abnormal. solder joint inspection equipment. 6. The solder joint inspection device for a semiconductor device according to claim 5, wherein the solder joint abnormality determining means determines the abnormality by detecting continuity of positive and negative values of the second-order differential value. 7. The solder joint abnormality determining means calculates the sum of values within a certain threshold value of the profile of the second-order differential value, and determines abnormality based on the sign or negative of the sum.
A solder joint inspection device for a semiconductor device according to .