JP2007178370A - Method for inspecting solder junction and method of manufacturing integrated circuit component - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an inspecting method for determining with higher accuracy whether a jointing state between package of integration circuit and a wiring board is good or poor. <P>SOLUTION: The method of inspecting solder joints for inspecting between a plurality of solder balls 5 arranged on the surface of the BGA package 10, and lands 12 provided on the printed wiring board 11, is provided with: detection processes S101 to S102; and determination processes S103 to S108. The detection processes S101 to S102 detect the distribution of elements contained in solder paste 16 applied on the lands 12 and is not contained in the solder balls 5 from the information obtained by irradiating the solder jointed parts with X-rays. The determination processes S103 to S108 determine the quality of the solder joints, based on the detected distribution of the elements. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a method for inspecting a solder joint state of an array package such as a BGA (Ball Grid Array) type package or a CSP (Chip Scale Package) type package mounted on a printed wiring board, and an integrated circuit component manufacturing method. It is.

In recent years, electronic devices such as mobile phones, personal computers, and video devices have been remarkably improved in performance and size and weight. What makes this possible is the mounting technology of the semiconductor device that is the core of the technology, and the density of packages for mounting the semiconductor device and the speed of signal processing are increasing. In particular, array packages such as BGA and CSP are attracting attention as a package form effective for increasing the number of terminals.
However, although packages such as BGA are excellent in increasing the number of terminals, due to their structure, when they are mounted on a printed wiring board, the junction with the printed wiring board is hidden by the package body. Laser-type visual inspection devices cannot observe the bonding state between the printed wiring board and the semiconductor device, and there is a problem that it is difficult to determine whether the bonding state is good or bad.
As a means for solving these problems, various methods have been proposed in which an X-ray inspection apparatus is used to observe a bonded portion of a package such as a BGA and a printed wiring board to determine whether the product is good or bad.
For example, the quality determination is performed by transmitting the joint using an X-ray transmission device and comparing the shape of the joint with other joints, for example, by comparing whether the area is large or small. In addition, an inspection method has been proposed in which the interface of the joint is observed from a three-dimensional shape image obtained by irradiating X-rays to determine pass / fail judgment.

Furthermore, as a method for inspecting with higher accuracy, for example, the fact that the gap between the solder joints often occurs in a direction parallel to the printed wiring board is used to be perpendicular to the main surface of the printed wiring board. Pass / fail judgment is performed by obtaining a cross-sectional image (so-called longitudinal tomographic image) (see Patent Document 1).
Moreover, the quality determination is performed by detecting the shadow of the lead content in the solder alloy with an X-ray transmission device (see Patent Document 2).
JP 2000-275191 A JP-A-10-170455

However, in the conventional method of determining the quality of the joint using X-rays, in response to the recent environmental problems, if a package such as BGA is mounted on a printed wiring board with lead-free solder that does not contain lead, Since there is no lead content, no shadow can be detected, and it is impossible to make a pass / fail judgment.
Also, the size of solder balls provided on a package such as BGA varies. For example, a tolerance of about 150 μm for a 600 μm solder ball is a good product in design. For this reason, when the solder paste is printed with a thickness of 150 μm and a package such as BGA having such a tolerance is mounted on a printed wiring board, the cross-sectional area at the center is small even though the bonding state is good. Therefore, it is difficult to determine whether the joining is good or bad.
Even if the size of the solder ball is larger than usual, it is difficult to determine the connection failure that occurs without melting the solder ball because of insufficient heating during the heat treatment.
In addition to the BGA package, other electronic components (for example, electrolytic capacitors, connectors, and chip components) are mounted on both sides of the printed wiring board on the printed wiring board. It is difficult to get close to the area, it is difficult to increase the resolution of the longitudinal section image and the resolution of the three-dimensional shape image by CT scan, and it is difficult to observe whether there is a gap between the solder ball and the printed wiring board. .

  Therefore, the present invention improves the problems of the above conventional solder joint inspection method, and inspects the joint state between the integrated circuit package and the printed wiring board more accurately, and the joint quality by the joint inspection method. An object of the present invention is to provide a method of manufacturing an integrated circuit component in which the reliability of connection is improved.

A solder joint inspection method as a first invention is a solder joint inspection method for inspecting solder joints between a plurality of solder balls arranged on the surface of an integrated circuit package and connection terminals provided on a printed wiring board. And a detection step and a determination step. In the detection step, the distribution of elements that are included in the solder paste applied on the connection terminals and not included in the solder balls is detected from information obtained by irradiating the X-rays to the portions to be soldered. In the determination step, the quality of the solder joint is determined based on the distribution of the detected elements.
Here, the “integrated circuit package” is, for example, a surface mounting package called a BGA type package or a CSP type package. “Solder balls” are, for example, rounded small solder materials called bumps. The “connection terminal” is, for example, an electrode called a land formed at a position where a solder ball of an integrated circuit package is mounted on a printed wiring board, and is formed of, for example, copper. Further, for example, a solder paste called cream solder is applied (printed) to the connection terminals. “Elements not contained in solder balls” means, for example, not only elements that are not contained in solder balls at all, but also elements that are not the main constituent elements of solder balls but are attached to solder balls in small amounts. It also means an element contained in a very small amount in a solder ball.

In solder bonding, an integrated circuit package and a printed wiring board are positioned and mounted. Further, soldering is performed by melting the solder balls and the solder paste by heating to the integrated circuit package or the printed wiring board to form a molten solder. At this time, if the solder joint is normally performed, for example, a material contained in the solder paste covers the surface of the molten solder. On the other hand, when the bonding is poor, a gap is formed between the solder paste and the solder ball, or the solder paste and the solder ball are not melted.
In the present invention, when solder bonding is normally performed in this way, it is possible to determine whether solder bonding is good or bad by utilizing the fact that the elements contained in the solder ball and the molten solder are different. That is, after solder joining, it is judged from the information obtained by irradiating the X-rays on the part where the solder joint is performed, whether or not the solder ball has become molten solder, and the quality of the solder joint is judged. As a result, it is possible to determine the quality of the bonding state between the integrated circuit package and the printed wiring board with higher accuracy.
The solder joint inspection method as the second invention is the first invention, wherein the element is any of the elements constituting the flux contained in the solder paste.

Here, the “flux” is a product obtained by adding a chemical or the like to a vegetable natural resin such as pine ani, for example, melts at a temperature lower than that of the solder, promotes the solder wetting phenomenon, It is used to cover the surface and prevent reoxidation.
In the present invention, for example, it is possible to determine the quality of the solder joint by utilizing the fact that the elements constituting the flux move to the solder ball side by melting the solder ball and the solder paste.
The solder joint inspection method as a third invention is the second invention, wherein the element is any of carbon, hydrogen, oxygen, chlorine, bromine and fluorine.
The flux is composed of carbon, hydrogen, oxygen, chlorine, bromine, fluorine, and the like. For this reason, it becomes possible to determine the quality of solder joint by detecting any of these. In particular, since the flux has a high carbon content, the quality of solder joints may be determined by detecting carbon.
A solder joint inspection method as a fourth invention is the first invention, wherein the detection step includes a step of irradiating X-rays from a direction substantially perpendicular to the printed wiring board, and a transmission X-ray of the irradiated X-rays And detecting the distribution of elements.

Here, in the detection step, the distribution state of the element in the portion to be soldered can be integrated and detected in a direction substantially perpendicular to the printed wiring board.
In the present invention, for example, it is possible to determine whether solder bonding is good or not by utilizing the fact that the material contained in the solder paste moves to the solder ball side by melting the solder ball and the solder paste. . That is, it is possible to determine whether the solder joint is good or bad by using the fact that the distribution of elements in the detected transmitted X-rays differs depending on whether or not such movement occurs.
The solder joint inspection method as the fifth invention is the fourth invention, wherein the determination step is normal when the detected element does not exist in the center of the part to be soldered. If it exists in the central portion, it is determined that the solder joint is defective.
When soldering is normally performed, for example, a material included in the solder paste covers the surface of the molten solder. For this reason, with transmitted X-rays from a direction perpendicular to the printed wiring board, when soldering is performed normally, the material contained in the solder paste is placed on the outer periphery of the part to be soldered (the part that becomes molten solder). Distributed. On the other hand, when the solder joint is defective, the material contained in the solder paste covers the surface of the solder paste. For this reason, in the transmission X-ray from the direction perpendicular to the printed wiring board, the material contained in the solder paste is distributed to the center of the portion to be soldered.

In the present invention, it is possible to determine the quality of the solder joint using the above phenomenon.
Further, this determination step may be automatically executed by image processing. For example, an image showing the distribution of elements in shading may be processed to determine the distribution of the material contained in the solder paste. By enabling such automatic inspection, it is possible to perform 100% inspection instead of sampling inspection, and it is possible to provide a highly reliable connection with stable quality.
The solder joint inspection method as a sixth invention is the first invention, wherein the detecting step detects a step of irradiating the portion to be soldered with X-rays, and detects fluorescent X-rays of the irradiated X-rays. And a step of detecting an element distribution of a portion to be soldered at a predetermined position in a direction substantially perpendicular to the printed wiring board.
Here, in the detection step, it is possible to detect the element distribution state in the cross section at a predetermined position of the portion to be soldered. For this reason, for example, it is possible to three-dimensionally detect the distribution state of elements in a portion to be soldered.
In the present invention, for example, it is possible to determine whether solder bonding is good or not by utilizing the fact that the material contained in the solder paste moves to the solder ball side by melting the solder ball and the solder paste. . That is, it is possible to determine whether the solder joint is good or bad by using the fact that the distribution of elements in the detected transmitted X-rays differs depending on whether or not such movement occurs.

The solder joint inspection method as the seventh invention is the sixth invention, wherein the determination step is normal when the detected element does not exist in the center of the part to be soldered. If it exists in the central portion, it is determined that the solder joint is defective.
When soldering is normally performed, for example, a material included in the solder paste covers the surface of the molten solder. For this reason, in the fluorescent X-rays in the part to be soldered, when the soldering is normally performed, the material contained in the solder paste is distributed on the outer peripheral part of the part to be soldered (the part that becomes the molten solder). On the other hand, when the solder joint is defective, the material contained in the solder paste covers the surface of the solder paste. For this reason, in the fluorescent X-rays at a predetermined position, the material contained in the solder paste is distributed to the center of the part to be soldered.
In the present invention, it is possible to determine the quality of the solder joint using the above phenomenon.
Further, this determination step may be automatically executed by image processing. For example, an image showing the distribution of elements in shading may be processed to determine the distribution of the material contained in the solder paste. By enabling such automatic inspection, it is possible to perform 100% inspection instead of sampling inspection, and it is possible to provide a highly reliable connection with stable quality.

According to an eighth aspect of the present invention, there is provided a method of manufacturing an integrated circuit component comprising: a step of solder-joining a plurality of solder balls arranged on the surface of an integrated circuit package and connection terminals provided on a printed wiring board; And a step of inspecting solder joints by the solder joint inspection method according to the present invention.
Here, the “integrated circuit component” is, for example, a component in which an integrated circuit package and a printed wiring board are joined by soldering.
In the present invention, since it includes the step of inspecting the solder joints by the solder joint inspection method as the first to seventh inventions, the reliability of the connection between the integrated circuit package and the printed wiring board is improved, and the integrated circuit with stable quality Parts can be provided.

  According to the present invention, it is possible to provide an inspection method for determining the quality of a bonded state between an integrated circuit package and a printed wiring board with higher accuracy. In addition, it is possible to provide a method of manufacturing an integrated circuit component in which the bonding quality is determined by the bonding portion inspection method and the connection reliability is improved.

[Embodiment 1]
Hereinafter, a method for inspecting a solder joint according to the first embodiment of the present invention will be described.
<About the overview>
In the solder joint inspection method, when a solder ball provided on the surface of a package for surface mounting such as a BGA package or a CSP package and a land provided on a printed wiring board are joined using a solder paste, the solder paste This utilizes the fact that the flux contained therein becomes a residue around the joint (molten solder).
The solder paste is a kneaded product of solder alloy and flux. Flux is an organic substance composed of pine crabs, activators, thixotropic agents and solvents. Pine jani or activator removes the oxide film at the joint in order for the solder alloy to melt and join. A thixotropic agent and a solvent are used for printing and applying a solder paste to a land portion of a printed wiring board with high accuracy.
The flux removes the oxide film on the surface of the joint at the time of solder joining. As a result, the solder paste spreads out and melts and solidifies with the solder balls. At this time, the flux moves to the outside of the molten solder and becomes a residue.
<About solder joints>
Hereinafter, the solder joint of the solder joint according to the first embodiment will be described with reference to the drawings.

FIG. 1 is a cross-sectional view of a BGA package for explaining solder bonding at a solder joint. FIG. 1 shows a cross-sectional view of a BGA package before being soldered.
As shown in FIG. 1, the BGA package 10 electrically connects the semiconductor chip 2, the BGA substrate 4 that fixes the semiconductor chip 2, and the electrode portion of the semiconductor chip 2 and the electrode portion of the BGA substrate 4. A resin outer body 1 that protects the gold wire 3, the semiconductor chip 2, the gold wire 3, and the electrode portion of the BGA substrate 4, and a solder ball 5 disposed on the surface opposite to the outer body 1, Consists mainly of.
The solder ball 5 is electrically connected to the electrode portion of the BGA substrate 4. Thereby, the soldered BGA package 10 and the printed wiring board 11 are electrically connected. The solder ball 5 may be a sphere having a diameter of 0.6 mm and may be made of a metal, but is formed of an alloy of Sn3Ag0.5Cu (Ag is 3 wt%, Cu is 0.5 wt%, and the rest is Sn). Also good.
Lands 12 as connection terminals are formed on the printed wiring board 11 at positions corresponding to positions where the solder balls 5 of the BGA package 10 are disposed. The land 12 is a member for electrical connection with components arranged on the printed wiring board 11 and is formed by etching or the like. A solder paste 16 having an alloy composition of Sn3Ag0.5Cu is printed on the land 12 by printing. The land 12 is formed with a thickness of 0.035 mm, and the solder paste 16 is formed with a thickness of 0.15 mm including the thickness of the land 12.

With the above configuration, the BGA package 10 is mounted on the printed wiring board 11 by solder bonding. Specifically, the solder balls 5 of the BGA package 10 and the lands 12 of the printed wiring board 11 are mounted so as to coincide with each other, heated to a temperature higher than the melting point of the solder alloy by a heating device such as a reflow furnace, and then cooled. Thus, solder bonding is performed.
FIG. 2 is a cross-sectional view of the BGA package 10 and the printed wiring board 11 after being joined by the solder joint described above.
As shown in FIG. 2, the land 12 of the printed wiring board 11 and the BGA package 10 are joined together by a solder joint portion 13 in which the solder balls 5 and the solder paste 16 are melted and solidified.
At this time, the solder joint portion 13 that is well joined is formed to a thickness of 0.55 mm, and the flux residue 15 is present on the surface. The flux residue 15 is a part of the flux contained in the solder ball 5 and the molten solder paste 16 adhered to the surface as a residue.
On the other hand, when the solder joint is defective, the flux residue 15 does not adhere around the solder ball 5 but adheres around the solder paste 16.

<About solder joint inspection method>
In the present embodiment, whether the solder joint is good or bad is determined using the phenomenon described above. This will be described more specifically with reference to FIGS. 3 and 4.
The solder joint inspection method shown in FIG. 3 includes a first step (S101 to S102) for detecting the distribution of the flux residue 15 from the information obtained by irradiating the X-rays to the part to be soldered, and the detected distribution. The second step (S103 to S108) for determining whether the solder joint is good or not based on the above.
FIG. 4 is an image showing the concentration distribution of carbon contained in the flux residue 15 obtained in the first step (S101 to S102). This concentration distribution is obtained by irradiating X-rays from the direction perpendicular to the printed wiring board 11 (the direction from the BGA package 10 side to the printed wiring board 11 side) with respect to the portion for determining the quality of solder bonding (S101). It is obtained by detecting transmitted X-rays (S102). That is, by detecting transmitted X-rays of X-rays irradiated from such a direction, an image in which the concentration of carbon contained in the flux residue 15 is integrated in the direction perpendicular to the printed wiring board 11 is obtained. That is, a portion containing a large amount of carbon is dark, and a portion not containing carbon is displayed lightly.

Carbon is present only in the flux residue 15 at the solder joint 13. For this reason, in the solder joint portion 13 with good solder joint, carbon is distributed only in the outer peripheral portion of the solder joint portion 13. For this reason, in the solder joint part 13 with good solder joint, a good joint image 21 in which carbon exists only in the outer peripheral part is obtained. That is, the well-bonded image 21 has an annular portion 21a with a high density at the outer periphery, and a circular portion 21b with a low density at the center.
On the other hand, when the solder joint is defective, as shown in FIG. 2, the solder ball 5 and the solder paste 16 are not joined, and the flux contained in the solder paste 16 does not move to the solder ball 5 side. For this reason, carbon located on the surface of the solder paste 16 is detected by transmitted X-rays, and a poor bonding image 22 in which carbon is also present in the central portion other than the outer periphery is obtained. That is, the poor bonding image 22 is a circular image having a substantially uniform darkness throughout.
In the second step (S103 to S108), the quality of the solder joint is determined based on the carbon concentration distribution image obtained in the first step (S101 to S102). Specifically, after the images shown in FIG. 4 are obtained, each image is digitally processed.
In the digital processing, each image is digitized as digital data corresponding to the darkness (S103), and binarization processing (S104) is performed using a predetermined threshold. Thereby, the image of the part containing carbon of a predetermined amount or more is replaced with black, and the image of the part containing carbon less than the predetermined amount is replaced with white. Here, the predetermined threshold is set to such a value that the darkness of the poorly bonded image 22 is replaced with black. Thereby, the annular portion 21a of the good bonding image 21 is replaced with a black region, the circular portion 21b is replaced with a white region, and the poor bonding image 22 is replaced with a black region.

Further, it is determined whether or not the size d of the white area at the center of each binarized image is greater than or equal to a predetermined size (S105). Here, the predetermined size is, for example, a size such as two-thirds of the diameter of the land 12. Here, when the determination result is affirmative (S105), it is determined that the image is the good joint image 21. On the other hand, if the determination result is negative, it is determined that the image is a poorly bonded image 22.
Such a determination is performed for all images. If the determination result of S105 is affirmative for all images, it is determined that the BGA package 10 and the printed wiring board 11 are well bonded, and the determination result is output (S107). On the other hand, if the determination result in S105 is negative even in one image, it is determined that the bonding between the BGA package 10 and the printed wiring board 11 is defective, and the determination result is output (S108). Note that products that are determined to have poor bonding are discarded or repaired.
The above process is performed by a control unit such as a computer connected to the X-ray irradiation apparatus.
<effect>
In the solder joint inspection method described above, it is possible to acquire the X-ray image as described above and determine the quality of the joint based on the carbon distribution. Therefore, even if the size of the solder balls 5 provided on the BGA package 10 varies, it is possible to determine the quality of the bonding with high accuracy.

As described above, in the present embodiment, the solder joint is inspected based on the carbon concentration distribution. For this reason, it is possible to perform non-destructive and high-accuracy determination of the quality of solder bonding of a BGA package, which cannot be inspected by an optical inspection apparatus or a laser inspection apparatus.
<Others>
(1)
In the above embodiment, it is described that the concentration of carbon contained in the flux is detected, but the element to be detected is not limited to this. For example, any element that is included in the solder paste 16 and not included in the solder ball 5 may be used, and any element that constitutes the flux may be used. Specifically, in addition to carbon, any of hydrogen, oxygen, chlorine, bromine, and fluorine may be detected. The “element not included in the solder ball 5” means not only an element that is not included in the solder ball 5, but also the surface of the solder ball 5 although it is not a main constituent element of the solder ball 5. It also means an element adhering to the solder ball 5 or an element contained in the solder ball 5 in a very small amount.
(2)
In the above embodiment, the BGA package 10 has been described as an example, but the present invention can also be applied to other array packages. Specifically, the present invention can be applied to a CSP package or the like.

(3)
In the above embodiment, the case where the second step of the solder joint inspection method is automated has been described. However, a human may determine the density distribution image obtained in the first step.
(4)
In the above embodiment, the second step has been described as determining whether the image is a good joining image 21 or a poor joining image 22 by using the size of the white region. However, the shape of the white region is taken into consideration. Also good. Specifically, the determination may be made based on whether or not the white area has the same shape as the land 12.
(5)
In the above embodiment, Sn3Ag0.5Cu is used as the solder paste 16, but other materials may be used. In the present invention, the same measurement is possible regardless of whether it contains lead or is lead-free.
(6)
Although an X-ray apparatus is used to obtain the carbon concentration distribution, other apparatuses have the same effect if an image of the carbon concentration distribution can be obtained.

(7)
In the above-described embodiment, it is described that the quality of solder joint is determined by irradiating X-rays and detecting transmitted X-rays. Here, the quality of the solder joint may be determined by detecting fluorescent X-rays.
With fluorescent X-rays, it is possible to detect element concentrations at various positions inside the object by adjusting the irradiation intensity.
For example, as shown in FIG. 5, the element concentration distribution of the cross section of the solder joint 13 at a predetermined height is obtained from the printed wiring board 11 by adjusting the X-ray irradiation concentration and detecting the fluorescent X-rays. Can do.
Here, the predetermined height is, for example, a position where the solder paste 16 and the solder ball 5 come into contact with each other when the solder paste 16 and the solder ball 5 are formed in a normal size. It is the position farthest from. That is, as described above, since the solder paste 16 is formed to have a thickness of 0.15 mm including the thickness of the land 12, the predetermined height is, for example, 0.15 mm.
The element concentration distribution image of the cross section of the solder joint 13 at the predetermined height is the same as that shown in FIG. Specifically, when the solder joint is good, a good joint image 21 is obtained, and when the solder joint is bad, a poor joint image 22 is obtained. Since the subsequent processing has been described above, the description thereof is omitted here.

The element concentration distribution image described above may be acquired for one cross section, or may be acquired for a plurality of cross sections having different heights by adjusting the X-ray irradiation concentration. When acquiring with a plurality of cross sections, it is possible to acquire an element concentration distribution image three-dimensionally, and it is possible to more accurately determine solder joints.
In particular, in such determination using fluorescent X-rays, as shown in FIG. 5, even when the BGA package 10 is mounted at the same position on both surfaces of the printed wiring board 11, the carbon dioxide for each BGA package 10 is It is possible to obtain a density distribution image.
In the above description, the predetermined height of the cross section for detecting the concentration distribution is set to 0.15 mm, for example, but if the height is 0 to 0.15 mm from the printed wiring board 11, it depends on the state of the solder paste 16. Therefore, it is possible to make an accurate determination.
(8)
Note that the structure shown in this embodiment mode is merely an example, and the present invention is not limited to these specific examples.

  The printed wiring board inspected by the solder joint inspection method of the present invention has high solder joint reliability and high long-term reliability. Therefore, it is useful for all electronic devices, but is particularly useful for products such as mobile phones, digital cameras, movies, and video devices that use many BGA (CSP) packages.

Sectional view of BGA package according to Embodiment 1 (before soldering) Sectional view of BGA package according to Embodiment 1 (after soldering) Flowchart for explaining a solder joint inspection method according to the first embodiment Explanatory drawing explaining the solder joint test | inspection method concerning Embodiment 1 Sectional view of BGA package according to Embodiment 2 (after soldering)

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Exterior body 2 Semiconductor chip 3 Gold wire 4 BGA board 5 Solder ball 11 Printed wiring board 12 Land 13 Solder joint 15 Flux residue 16 Solder paste 21 Good joint image 22 Bad joint image

Claims (8)

A solder joint inspection method for inspecting solder joints between a plurality of solder balls arranged on the surface of an integrated circuit package and connection terminals provided on a printed wiring board,
A detection step of detecting a distribution of elements contained in the solder paste applied onto the connection terminals and not included in the solder balls, from information obtained by irradiating the X-rays on the soldered portions; and ,
Based on the detected distribution of the elements, a determination step for determining whether the solder joint is good or bad,
Comprising
Solder joint inspection method. The element is any of the elements constituting the flux contained in the solder paste.
The solder joint inspection method according to claim 1. The element is any of carbon, hydrogen, oxygen, chlorine, bromine and fluorine.
The solder joint inspection method according to claim 2. The detection step includes
Irradiating X-rays from a direction substantially perpendicular to the printed wiring board;
Detecting transmitted X-rays of the irradiated X-rays and detecting the distribution of the elements;
Having
The solder joint inspection method according to claim 1. The determination step includes
When the detected element does not exist at the center of the part to be soldered, it is determined that the solder joint is normal, and when it is present at the center, it is determined that the solder joint is defective. ,
The solder joint inspection method according to claim 4. The detection step includes
Irradiating the soldered portion with X-rays;
Detecting the X-ray fluorescence of the irradiated X-ray, and detecting the distribution of the element in the soldered portion at a predetermined position in a direction substantially perpendicular to the printed wiring board;
Having
The solder joint inspection method according to claim 1. The determination step includes
When the detected element does not exist at the center of the part to be soldered, it is determined that the solder joint is normal, and when it is present at the center, it is determined that the solder joint is defective. ,
The solder joint inspection method according to claim 6. Solder bonding a plurality of solder balls arranged on the surface of the integrated circuit package and connection terminals provided on the printed wiring board;
A step of inspecting a solder joint by the solder joint inspection method according to claim 1;
Comprising
Integrated circuit component manufacturing method.

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