JPH07283598A - Method for mounting electronic device - Google Patents

Abstract

PURPOSE:To accurately, rapidly align an electronic device such as a grid array package, etc., having electrodes on a rear surface on a printed board when the device is mounted on the board. CONSTITUTION:1) A method for mounting an electronic device 1 comprises the steps of opening a through hole 2 opened at a package 1 of an electronic device, providing a reference mark 4 on a printed board 3, aligning the hole 2 at the mark 4 and then mounting the device 1 on the board 3. 2) A visual observation is used for the aligning, or a light beam is scanned, a scattered light is received from the hole, and its position is detected. 3) The package 1 of the device is a ball grid array package or a land grid array package. 4) The hole 2 is opened through the electrode board of the package 1.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electronic device mounting method, and more particularly to a positioning method for surface mounting an electronic device such as a grid array package having electrodes on the back surface on a printed circuit board.

When surface-mounting an electronic device such as a flat package, it is necessary to accurately mount a large number of electrodes with a narrow pitch at predetermined positions on a printed circuit board, which results in high accuracy between the package and the printed circuit board. Alignment is required. Therefore, even in a grid array package having a large number of electrodes with a narrow pitch on the back surface, similar alignment accuracy is required when mounting on the surface.

[0003]

2. Description of the Related Art Conventionally, when an electronic device is mounted on a printed circuit board, alignment is performed by image recognition. However, image recognition has a limit in image processing capability, and the position of the package is determined not by the electrodes but by the outer shape. Due to the alignment, accurate alignment is difficult when there are electrodes on the back surface of the package.

[0004]

SUMMARY OF THE INVENTION It is an object of the present invention to accurately and quickly align a printed circuit board when mounting an electronic device of a grit array package having an electrode on the back surface.

[0005]

[Means for Solving the Problems] To solve the above problems, 1) a through hole 2 is opened in a package 1 of an electronic device, and a reference mark 4 is provided on a printed circuit board 3;
The electronic device after aligning with the reference mark 4
1) Mounting method of electronic device by mounting on the printed circuit board 3, or 2) Visual alignment is used for the alignment, or light such as laser light or light emitted from a light emitting diode is scanned to scatter light from the through hole. The above-mentioned 1 which receives the light and detects the position
Or 3) the mounting method of the electronic device described above, or 3) the mounting method of the electronic device according to 1 or 2, wherein the package 1 of the electronic device is a ball grid array package or a land grid array package, or 4) the through hole 2 is It is achieved by the method for mounting an electronic device described in 1 or 2 or 3 above, which is opened through the electrode substrate of the package 1.

[0006]

FIG. 1 is a diagram for explaining the principle of the present invention. In the figure, 1 is an electronic device of a grid array package (or land array package), 2 is a through hole opened in the grid array package, 3 is a printed circuit board, 4 is a reference mark for alignment provided on the printed circuit board,
5 is a laser beam generator, 6 is a laser beam receiver, 7 is an analyzer, 8 is a computer, and 9 is an alignment device.

Electronic device of grid array package
1 can be held and moved by the chuck of the alignment device 9. In the present invention, first, a reference mark 4 for alignment is provided at a predetermined position on a printed board by printing or the like, while one or more through holes 2 are provided through the electrode board of the grid array package. Since this through hole is formed on the same surface as the electrode, it can be formed with extremely high precision for the electrode.

Next, the reference mark 4 for alignment on the printed circuit board is scanned at a constant speed with a laser beam through a through hole 2 formed in the package through the electrode substrate of the package, and the scattered light at that time is received by a receiver 6. Analyzer
The results are analyzed by 7, and the results are fed back to the alignment device 9 by the computer 8, and the alignment device 9 corrects the alignment deviation.

Therefore, by aligning the through hole formed with high precision with respect to the electrode for the above reason and the reference mark on the printed circuit board, the package electrode and the electrode on the printed circuit board can be accurately positioned. It becomes possible to match. At this time, accurate and quick alignment can be performed by using laser beam scanning.

[0010]

FIG. 2 is an explanatory view of an embodiment of the present invention. Figure 1
In the above, the example in which the through hole 2 was opened in the package body through the electrode substrate was explained, but here we show an example in which it is opened only in the electrode substrate of the package.

In the figure, 10 is an electronic device of a ball grid array package (or land grid array package) (consisting of an electrode substrate 10A and a semiconductor chip sealing portion 10B located thereon), 2 is a grid array package electrode. It is a through hole opened in the substrate 10A.

In the embodiment, a laser light generator and a laser light receiver are used, but instead of this, a light emitting diode (L
A light generation device and a light reception device according to ED) may be used.
Alternatively, visual alignment may be used.

FIGS. 3A to 3D are plan views of the ball grid array package of the embodiment. The figure shows an example in which two round or square through holes 2 are opened at different positions. FIG. 4 is a diagram showing an example of the relationship between the through hole 2 and the reference mark 4.

FIGS. 5 (A) and 5 (B) are explanatory views of the alignment example of the embodiment. In FIG. 5A, for example, a He-Cd laser is used as the laser light generator, and a light intensity detector is used as the laser light receiver. The laser beam scans the through hole 2 and the reference mark 4 at a constant velocity in the direction of the arrow shown in the figure.

Scattered light generated as a result of scanning the laser light at a constant speed is passed through the receiver and obtained as an electric signal as shown in FIG. 5B with respect to time. The analyzer 7 analyzes the electrical signal obtained in this way, obtains the transit time (representing the constant velocity scanning distance) between the edge of the through hole 2 and the reference mark, and sends the data to the computer 8.

The computer 8 calculates the deviation of the reference mark 4 from the central portion of the through hole 2 from the data from the analyzer 7, and it is necessary to move the reference mark 4 so as to reach the central portion of the through hole 2. Calculate if there is. Also,
At this time, convert time into distance. Note that this conversion can also be performed with the analyzer 7. Furthermore, the calculated movement amount is instructed to the alignment device 9.

The aligning device 9 moves the package by a designated distance according to an instruction from the computer 8 and moves the package to a regular position. Then, the laser beam is again scanned at a constant speed to check whether the reference mark is located in the center of the through hole.

As a result, if the reference mark does not come to the center of the through hole at once, the above operation is repeated.

[0019]

According to the present invention, when mounting an electronic device of a grid array package having an electrode on the back surface,
Accurate and quick alignment is possible on the printed circuit board. As a result, the mounting yield and mass productivity can be improved.

[Brief description of drawings]

FIG. 1 is an explanatory view of the principle of the present invention.

FIG. 2 is an explanatory diagram of an embodiment of the present invention.

FIG. 3 is a plan view of the ball grid array package of the embodiment.

FIG. 4 is a diagram showing an example of a relationship between a through hole and a reference mark.

FIG. 5 is an explanatory diagram of a positioning example of the embodiment.

[Explanation of symbols]

1 Electronic device of grid array package 2 Through hole opened through electrode substrate in grid array package 3 Printed circuit board 4 Reference mark for alignment provided on printed circuit board 5 Laser light generator 6 Laser light receiver 7 Analyzer 8 Computer 9 Aligner 10 Electronic device in ball grid array package

Claims (4)

[Claims] 1. A through hole in an electronic device package (1).
(2) Open and the reference mark (4) on the printed circuit board (3)
And mounting the electronic device (1) on the printed circuit board (3) after aligning the through hole (3) with the reference mark (4). 2. The method for mounting an electronic device according to claim 1, wherein the position is detected by using visual observation or by scanning a light beam and receiving scattered light from the through hole to detect the position. 3. The electronic device mounting method according to claim 1, wherein the electronic device package (1) is a ball grid array package or a land grid array package. 4. The method of mounting an electronic device according to claim 1, wherein the through hole (2) is opened through the electrode substrate of the package (1).