JPS62282770A - Inspecting method for soldering - Google Patents

Abstract

PURPOSE:To improve the inspection accuracy by measuring a temperature of each soldered part of a body to be inspected, by a non-contact type an infrared thermometer, and discriminating whether a soldered state is good or not, through a means such as a constant temperature line, etc., of each part of the body to be inspected. CONSTITUTION:With respect to a soldered part 03 of a body to be inspected 02 on a printed circuit board 01, an infrared temperature sensor camera 04 is provided, a temperature is measured, and also, a heating value and a temperature are analyzed and compared by an image processor 05. In this case, a result of analysis is displayed as a constant temperature line 08 on a TV monitor 06. By comparing and collating the constant temperature line 08 with a constant temperature line of good soldering, whether the soldered part 03 is good or not is discriminated. In this way, a defect of soldering can be detected appropriately without depending on only a visual sense of an inspector, therefore, the inspection accuracy is improved remarkably.

Description

DETAILED DESCRIPTION OF THE INVENTION 3. Detailed Description of the Invention Field of Industrial Application The present invention relates to a method for inspecting soldering of electronic components, and particularly to a method of inspecting fine solder parts such as soldering of chip components.

BACKGROUND OF THE INVENTION Conventionally, this type of soldering inspection method includes a method of inspecting external defects by identifying CCD television images;
Alternatively, identify any defects in the solder using ultrasonic flaw detection,
A method of testing has been proposed.

Problems to be Solved by the Invention However, since the above-mentioned conventional CCD television image recognition method is only an appearance recognition method, it has the disadvantage that it is not possible to determine the soldering condition of the shadow part of the image, that is, the bottom of the electrode. There is.

Next, the ultrasonic flaw detection method has the disadvantage that it must be performed underwater.

The present invention has been made in view of the above-mentioned conventional circumstances, and
SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a new soldering inspection method which makes it possible to eliminate the above-mentioned drawbacks inherent in the conventional techniques.

Means for Solving the Problems In order to achieve the above object, the soldering inspection method according to the present invention detects various soldering defects in the reflow soldering method, such as irregular or excessive amount of solder, or problems with chip components. Unsoldered electrodes and unsoldered electrodes on the board, misalignment of solder parts, etc. are determined by analyzing the temperature and amount of heat.

The heat I of some parts of the solder is the sum of the amount of heat derived from the specific heat of the individual parts and the electrodes of the board, which is almost constant, and the amount of heat held by the solder, which varies depending on the amount, and the heat conduction of the materials of the solder and each electrode. shows the heat preservation status of one individual because it is in good condition. Therefore, differences in the amount of heat and heat distribution associated with each volatile defect can be sufficiently detected.

Embodiment Next, a preferred embodiment of the present invention will be specifically explained with reference to the drawings.

FIG. 1 is a sketch for explaining one embodiment of the present invention.

In FIG. 1, reference number 01 is a printed circuit board on which a sample chip component is mounted, and a solder portion 03 of a flat package component, that is, a chip component, of sample 02 is measured by an infrared temperature sensor/camera 04, and an image processing device 05
Analysis and comparison of the amount of heat and temperature is performed using the image processing device 05.The results of the comparison with the image processing device 05 are displayed on the 7V monitor θB, and compared to the isolayer line 07 with good soldering as shown in Fig. 2, there are defects as shown in Fig. 3. Isolayer line 08 of solder part 09 with
Defects in soldering are determined based on the difference between the two.

A certain temperature condition is applied to the specimen 02 immediately after reflow, and the quality of the soldering state can be determined based on the temperature difference between the specimen 02 before and after the application.

It is also possible to measure the temperature distribution with an infrared surface thermometer, draw isolayer lines, and use image recognition processing by the image processing device 05 to determine whether soldering is good or bad.

By drawing the isothermal distribution in color and determining the quality of soldering through color recognition processing, relatively easy and accurate determination is possible.

As described in detail, according to the present invention, soldering defects can be accurately detected by analyzing the flu degree and heat amount of the soldered state after reflow. Therefore,
For example, by installing an inspection machine applying the inspection method according to the present invention near the exit of a conveyor reflow furnace, it is possible to easily identify soldering defects that could only be detected by the visual sense of an inspector using a hot wire. becomes possible.

Furthermore, it has the effect of making it possible to identify even finer defects that cannot be visually identified.

[Brief explanation of drawings]

Figure 1 is a sketch for explaining one embodiment of the present invention, Figure 2 is a diagram showing a normal soldered TV monitor surface, and Figure 3 is a diagram showing a normal soldered TV monitor surface.
The figure shows a soldered T'l/monitor screen with a defect. 01, , Sample substrate, 02. , ,Electronic components in the sample, 03, ,How many parts of solder in the sample, 04. ,
, infrared temperature sensor, 05. , ,Image processing device, (
1G, , T'V Monitor, 07. , , Normal isostratic line, 08. , ,Anomalous isostratic line, 09. , ,
defective part

Claims (4)

[Claims] (1) When reflow soldering electronic components, the temperature of each soldered part of the reflow soldered specimen is measured with a non-contact infrared thermometer, and the quality of the soldering is determined by the difference in temperature from the already measured specimen. A soldering inspection method characterized by discrimination. (2) Claim No. (1) characterized in that a certain temperature condition is applied to the sample immediately after reflow, and the quality of the soldering condition is determined based on the temperature difference between the sample before and after the application.
Soldering inspection method described in section. (3) The temperature distribution is measured with an infrared surface thermometer to draw isothermal lines, and the quality of the soldering is determined by image recognition processing.
Soldering inspection method described in ). (4) The soldering inspection method according to claim (3), characterized in that the quality of the soldering is determined by color recognition processing of the isothermal distribution in color.