JP3107070B2 - Inspection device and inspection method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an inspection apparatus and an inspection method, and more particularly to a ball grid array (BG).
A: An inspection apparatus and an inspection method suitable for use in a Ball Grid Array) package.

[0002]

2. Description of the Related Art A BGA package is used for mounting an integrated circuit component such as a semiconductor element.
Since the electrode surfaces are bonded to each other so as to be opposed to each other, it is difficult to confirm the connection state of the components after mounting. Therefore, it is important to detect a defect at the component stage of the BGA package alone. Since the connection terminals of the BGA package are spherical terminals made of solder, they are glossy, and it is very difficult to inspect the shape from the appearance.

A method of inspecting the appearance of a solder ball used in a conventional BGA package will be described with reference to FIGS. In the method shown in FIG. 3, a laser beam emitted from a laser irradiator 5 installed diagonally above the solder ball 3 of the BGA package 1 installed on the measurement table 2 emits a slit-shaped laser beam, and the laser In this method, the light is captured by the CCD camera 12 provided above and the height of the solder ball 3 is calculated from the semi-elliptical shape of the reflected image.

That is, in this method, the solder balls 3
Is larger or smaller than a given size,
When the shape is distorted, the shape is reflected in the reflected image of the laser. Therefore, the shape of the solder ball 3 can be estimated to some extent from the reflected image of the laser.

The method shown in FIG. 4 irradiates a laser beam onto a solder ball 3 of a BGA package 1 placed on a measuring table 2 from a laser irradiator 5 placed above the same via a half mirror 6 while scanning a laser beam. The light reflected from the surface of the solder ball 3 is reflected by the half mirror 6 and captured by the CCD camera 12.

In this method, information on the intensity of the laser reflected light is processed and converted into the shape of the solder ball 3, and this is displayed in a contour line. If the size of the BGA solder ball 3
Can be estimated.

[0007]

However, the method shown in FIG.
In order to detect the height of the spot, it is not enough to irradiate the laser beam in a spot, and it is necessary to make the slit shape,
There is a problem that image processing takes time. Further, for example, when the upper portion of the BGA solder ball 3 is crushed and the actual height is changed, the difference cannot be identified and the accurate height of the solder ball 3 cannot be measured. There is a problem.

In the method shown in FIG. 4, the height of the BGA solder ball 3 is calculated from the intensity of the reflected light obtained by scanning the laser, so that the scanning is performed to determine the height accurately. It is necessary to increase the resolution by shortening the interval. On the other hand, if the resolution is increased, there is a problem that the measurement time becomes longer. In addition, it is liable to be affected by the reflectance of the solder ball 3, and in order to perform fine scanning, it is necessary to perform measurement on a high-precision XY table, and there is a problem that equipment becomes expensive.

For this reason, although it is an important inspection to ensure the quality of one of the BGA package,
The conventional method cannot easily and accurately detect the height of the solder ball 3, and often requires a visual inspection that requires man-hours. However, more pins,
As the pitch becomes narrower and the ball diameter becomes smaller, it is necessary to establish a simple and accurate appearance inspection method.

The present invention has been made in view of the above problems, and a main object of the present invention is to provide a BGA package capable of simply and accurately measuring the height of a solder ball and performing a visual inspection of the BGA package. An object of the present invention is to provide an inspection device and an inspection method.

[0011]

In order to achieve the above object, according to a first aspect of the present invention, a light irradiator and a light reflected by the object are detected on the object to be inspected. A light receiver, and, in an inspection apparatus for inspecting whether or not the external shape of the object to be inspected is a desired shape, a plate transmitting light provided with a recess having a shape substantially equal to the desired shape, The inspection object and the inspection object are disposed on the inspection object.
Optical path shift that occurs in relation to the size of the gap between the dent
Characterized by comprising means for detecting
And

According to a second aspect of the present invention, there is provided a second aspect, comprising: an optical transmitter and an optical receiver, irradiating an object to be inspected with the optical transmitter, and detecting the reflected light by the optical receiver. Thus, in the inspection method for inspecting whether or not the external shape of the object to be inspected is a desired shape, a light-transmitting plate provided with a depression having a shape substantially equal to the desired shape is provided on the object to be inspected. The optical receiver detects an optical path shift generated in correlation with the size of the gap between the inspection object and the depression, and inspects the shape of the inspection object from the detection result.

According to a third aspect of the present invention, there is provided a laser irradiator on a BGA package having solder balls arranged in an array, and a screen for displaying light reflected by the solder balls. B for inspecting whether or not the external shape of the solder ball is a desired shape
A GA package inspecting apparatus, wherein a gauge plate in which depressions having substantially the same shape as normal-sized solder balls are arranged in an array is provided on the BGA package.

Further, according to a fourth aspect of the present invention, in a fourth aspect, a laser irradiator and a screen are provided, and the laser irradiator irradiates a laser beam to the solder balls arranged in an array on a BGA package. Is displayed on the screen, thereby inspecting whether or not the external shape of the solder ball is a desired shape, wherein the BGA package has a shape substantially equal to a normal size solder ball on the BGA package. Providing a gauge plate in which the depressions are arranged in an array, displaying the deviation of the optical path of the laser light generated in correlation with the size of the gap between the solder ball and the depression on the screen, and from the magnitude of the deviation. The size of the solder ball is determined.

In the present invention, it is preferable that the gauge plate is made of glass or plastic.

As described above, according to the present invention, since the gauge plate is provided, and the shape of the solder ball of the BGA package is inspected by utilizing the gap formed between the gauge plate and the solder ball, high-speed and accurate inexpensive equipment is used. Inspection becomes possible.

[0017]

DESCRIPTION OF THE PREFERRED EMBODIMENTS In a preferred embodiment of the BGA package inspection apparatus according to the present invention,
A depression (4a in FIG. 2) on the package (1 in FIG. 2) having substantially the same shape as a normal size solder ball (3a in FIG. 1).
A gauge plate (4 in FIG. 2) is arranged in an array, and the solder ball is irradiated with a laser beam, and is correlated with the size of the gap between the defective-sized solder ball (3b in FIG. 2) and the depression. The deviation of the optical path of the laser light generated as a result is displayed on a screen, and it is inspected from the magnitude of the deviation whether the appearance of the solder ball is a desired shape.

[0018]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a block diagram showing an embodiment of the present invention; FIG. 1 and 2 are cross-sectional views schematically illustrating a method of inspecting a BGA package according to an embodiment of the present invention. FIG. 1 illustrates a case where a solder ball has a normal size. Reference numeral 2 indicates a case where the size of the solder ball is defective.

First, in the BGA package inspection apparatus according to the present embodiment, a gauge plate 4 made of a material such as glass that transmits laser light is attached to a BGA package 1 installed on a measurement table 2. The gauge plate 4 has a recess 4a provided corresponding to the shape of the solder ball 3a having a normal size. When the shape of the solder ball is normal, the solder ball 3a is formed.
A small and uniform gap is formed between the gauge plate 4 and the recess 4 a of the gauge plate 4.

Further, a laser irradiator 5 is installed diagonally above the BGA package 1, and the laser beam transmitted through the half mirror 6 is reflected on the surface of the solder ball 3a and returns to the half mirror 6 again. The laser beam reflected by the laser beam enters the screen 7 and forms a laser reflection image.

Next, a method of inspecting the shape of a solder ball by the BGA package inspecting apparatus of this embodiment will be described. In FIG. 1, first, a BGA package 1 is placed on a measurement table 2 which is kept horizontal, and a gauge plate 4 having a depression 4a having a ball size and a slight clearance is set thereon. Since the gauge plate 4 is aligned with the height of the solder ball 3a, when the size of the solder ball is normal, the clearance between the depression 4a of the gauge plate 4 and the solder ball 3a is almost zero.

In this state, when a laser beam is emitted from the laser irradiator 5, the laser beam enters the gauge plate 4 and then goes straight inside the gauge plate 4 to reach the boundary with the solder ball 3a. Since the clearance between the solder ball 3a and the solder ball 3a is substantially zero, the laser beam is reflected by the solder ball 3a and then reenters the gauge plate 4 at substantially the same position.

The laser beam reflected according to the angle of the surface of the solder ball 3a passes through a predetermined optical path and is reflected by the half mirror 6, and is projected on the screen 7 as a laser reflection image 9a of a normal size solder ball. You. By displaying the center of the laser reflected image 9a on the screen as the target mark 8, it can be used as a reference point in the following inspection.

Next, FIG. 2 will be described. FIG. 2 shows a case where the size of the solder ball is defective (in this case, the size is small). Here, similarly to FIG. 1, when the BGA package 1 and the gauge plate 4 are set on the measurement table 2, even if the defective size solder balls 3b are mixed, the gauge plate has a high height when the ball size is normal. So it will be aligned
At a place where the ball size is normal, the clearance between the gauge plate 4 and the solder ball 3a becomes almost zero, while at the position of the defective size solder ball 3b, a gap is generated therebetween.

In this state, when a laser is irradiated from the laser irradiator 5, the laser beam incident on the gauge plate 4 travels straight inside the gauge plate 4 and reaches the inner wall.
Since there is a gap between the gauge plate 4 and the solder ball 3b, the optical path of the solder ball 3b greatly shifts while being reflected on the surface of the solder ball 3b and returning to the inner wall of the gauge plate 4 as shown in FIG. become.

The laser light whose optical path is greatly shifted in this way is reflected by the half mirror 6 and is projected on the screen 7 as a laser reflection image 9b of a defective-sized solder ball. That is, the gauge plate 4 and the solder balls 3b
The laser reflected image 9b is shifted from the target mark 8 according to the gap between the target mark 8 and the laser reflected image 9b. Accordingly, the laser reflection image 9b on the screen 7 and the target mark 8
By measuring the displacement of the solder ball 3b, the size of the gap between the gauge plate 4 and the solder ball 3b, that is, the height of the solder ball 3b can be measured.

As described above, according to the method of the present embodiment, the height of the solder ball 3b is measured by measuring the size of the void generated between the defective size solder ball 3b and the gauge plate 4. Therefore, unlike the conventional method of measuring the height of a solder ball by image processing of a laser reflection image, it is not necessary to make a laser beam into a slit shape or scan, and a laser is applied to one solder ball. The height of the solder ball can be accurately detected only by irradiating the light once, so that high-speed measurement can be performed.

In this embodiment, an example in which glass is used as the material of the gauge plate has been described. However, the present invention is not limited to the above material, but may be any transparent material that can transmit laser. It is clear. Therefore, for example, it may be made of acrylic, polycarbonate, or the like.

[0029]

As described above, according to the present invention,
A BGA component stage in which the height of the solder balls formed on the BGA package can be accurately and easily inspected, and therefore, the connection terminals are on the back surface and the soldering state of the connection terminals cannot be visually checked after mounting. The quality check can be performed at a lower cost and at a higher speed than in the prior art, and there is an effect that the quality can be greatly improved and the cost can be greatly reduced.

The reason is that, in the present invention, since a depression corresponding to the shape of a normal-sized solder ball is formed in a gauge plate made of a material that transmits laser light, such as glass, the solder ball is defective. A gap is formed between the solder ball and the recess of the gauge plate, and the optical path is largely shifted before the laser beam is reflected on the surface of the solder ball and returns again. Is shifted from the target mark. By measuring the displacement, the size of the gap between the gauge plate and the solder ball, that is, the height of the solder ball can be measured.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view for explaining a structure of a BGA package inspection apparatus according to an embodiment of the present invention, showing a case where a solder ball has a normal size.

FIG. 2 is a cross-sectional view for explaining a structure of a BGA package inspection apparatus according to one embodiment of the present invention, showing a case where a solder ball has a defective size.

FIG. 3 is a cross-sectional view illustrating a conventional BGA package inspection device.

FIG. 4 is a sectional view showing a conventional BGA package inspection device.

[Explanation of symbols]

 Reference Signs List 1 BGA package 2 Measurement table 3 Solder ball 3a Solder ball of normal size 3b Solder ball of defective size 4 Gauge plate 4a Depression 5 Laser irradiator 6 Half mirror 7 Screen 8 Target mark 9a Laser reflection image of solder ball of normal size 9b Fault Laser reflection image of solder ball of size 10 CCD camera 11 Reflection surface image 12 Image converted to contour line

Claims (6)

(57) [Claims] A light irradiator; and a light receiver for detecting a light reflected by the object, the external shape of the object being a desired shape. In the inspection device for inspecting whether or not, a plate that transmits light provided with a depression having a shape substantially equal to the desired shape is disposed on the inspection object, and a plate between the inspection object and the depression is provided. Correlated with the size of the gap
For detecting the optical path shift caused by the optical receiver
Equipped with an inspection device, characterized in that. 2. An external shape of an object to be inspected by irradiating an object to be inspected with the light irradiator and detecting light reflected from the object by the optical image receiver. In an inspection method for inspecting whether or not a desired shape is provided, a light-transmitting plate provided with a depression having a shape substantially equal to the desired shape is disposed on the inspection object, and the inspection object and An inspection method, comprising: detecting an optical path shift occurring in correlation with the size of a gap between the hollow and the depression by the optical receiver; and inspecting the shape of the inspection object from the detection result. 3. A ball grid array (BGA) package having solder balls arranged in an array,
A BGA package inspection device, comprising: a laser irradiator; and a screen for displaying light reflected by the solder balls, wherein the BGA package inspection device inspects whether or not the external shape of the solder balls is a desired shape. A BGA package inspection apparatus, wherein a gauge plate in which depressions having substantially the same shape as normal-sized solder balls are arranged in an array is provided thereon. 4. The BGA package inspection apparatus according to claim 3 , wherein said gauge plate is made of one of glass and plastic. 5. A BG comprising a laser irradiator and a screen.
By irradiating laser light to the solder balls arranged in an array on the A package by the laser irradiator and displaying the reflected light on the screen, it is inspected whether or not the external shape of the solder balls is a desired shape. A method of inspecting a BGA package, comprising: providing, on the BGA package, a gauge plate in which depressions having a shape substantially equal to a solder ball having a normal size are arranged in an array, and forming a gap between the solder balls and the depressions. A method for inspecting a BGA package, comprising: displaying a shift of an optical path of laser light generated in correlation with the size on the screen, and judging a size of the solder ball from the size of the shift. 6. The BGA package inspection method according to claim 5 , wherein said gauge plate is made of one of glass and plastic.