JPH01239482A - Testing method for resin-sealed semiconductor device - Google Patents

Abstract

PURPOSE:To detect a microcrack and to securely evaluate a test result with high accuracy by pressing water in the semiconductor device at room temperature, immersing it in liquid held above the boiling point of water, and confirming bubbling through the vaporization of the water. CONSTITUTION:Solder 8 is melted in a solder tank 7 with a temperature control function and the semiconductor device is immersed therein. Compressed air 14 is sent to a pressure applying device 12 through a pressure valve 13, and consequently the water 20 is pressed in the semiconductor device 9. The air is discharged through a vent valve 15 after the water is pressed in, and the semiconductor device 9 is taken out of a beaker 12. Lastly, the semiconductor device 9 wherein the water is pressed in is immersed in the liquid 17 held above 100 deg.C by the liquid tank 16 with the temperature control function by using a jig 18. Clear air bubbles are found in the semiconductor device where the water is pressed as compared with a semiconductor device 9 where no water is pressed, and it is evident that the certainty of the evaluation result is improved.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention applies mechanical environmental tests 11r to resin-sealed semiconductor devices.
Improving the certainty of evaluation results when carried out 1! r: Regarding the test method to be realized.

Conventional technology Resin-encapsulated semiconductor devices (hereinafter referred to as semiconductor devices) are
Due to the demand for higher mounting density on printed circuit boards, their shapes are becoming smaller and thinner. For this reason, in recent years, as a mounting method, methods such as solder immersion and infrared reflow, in which the entire semiconductor device is rapidly heated to a high temperature of 200° C. or higher, have been adopted. Therefore, the semiconductor device i) thermal shock resistance is decreasing. Figure 2 (a) (bl shows an example in which cracks occurred in the resin part of a semiconductor device as a result of a soldering heat resistance test, which is one of the mechanical environment tests used as a test method to evaluate the thermal shock resistance of semiconductor devices. FIG. 2 (al (b)) shows a semiconductor device in which a chip 2 is mounted on a die pad 1, and the chip 2 and a lead frame 3 are connected with a wire 4, which is then sealed with a resin 5. This figure shows how a crack 6 was generated in the resin 5 starting from a part of the corner of the die pad 1 when the entire semiconductor device was immersed in molten solder (183°C). However, due to the rapid temperature changes applied to the entire semiconductor device, cracks in the resin part 6
occurs, indicating that the thermal shock resistance is reduced. Furthermore, similar failures may occur when equipment using semiconductor devices is used outdoors. This is because in an outdoor environment, the range of temperature changes in the environment expands, and these changes are applied repeatedly. In addition, even in the same outdoor field, in the automotive field such as automobiles, in addition to the repeated environmental temperature changes, mechanical vibrations and impact forces are applied, so if these exceed the strength of the resin part of the semiconductor device, the may occur. In contrast to the soldering heat resistance test mentioned above, which evaluates the thermal shock resistance during mounting of semiconductor devices, evaluation test methods for repeated environmental temperature changes, mechanical vibrations, and shocks include thermal shock tests, vibration tests, and impact tests. and so on. These are a part of the mechanical environment test, and conventionally, visual judgment is usually adopted as a method for evaluating the test results.

Problems to be Solved by the Invention The nail 6 of the resin part shown in FIG.
Usually, the presence or absence of the occurrence is visually determined using magnification a of about 0 to 30 times. However, it is difficult to identify cracks by modifying their shape and size.
Mere visual confirmation has its limits. Therefore, there is a problem in that the IM accuracy and reproducibility of the heat resistance evaluation results of semiconductor devices are impaired.

SUMMARY OF THE INVENTION Therefore, it is an object of the present invention to solve the above-mentioned conventional problems and to improve the accuracy of evaluation results of mechanical environment tests of semiconductor devices.

Means for Solving the Problems In the semiconductor device testing method of the present invention, after conducting a mechanical environment test, water is forced into the semiconductor device in a high-pressure atmosphere at room temperature, and the test method is immersed in a liquid at a temperature higher than the boiling point of water (100°C). This is a method in which foaming from the resin shoe is confirmed by immersion in the resin due to the evaporation of water.

Effects As mentioned above, if water is injected into the inside of the semiconductor device in a high-pressure atmosphere at room temperature after a mechanical environment test is performed on the semiconductor device, if a crack occurs in the resin part of the semiconductor device during the mechanical environment test, Water is forced into this crack. Thereafter, it is immersed in a liquid at a temperature higher than the boiling point of water (100° C.), and the water press-injected into the crack evaporates and expands, which is detected as bubbles around the crack. The present invention utilizes the evaporative expansion effect of water to detect fine particles that are difficult or impossible to detect with the naked eye. Significant improvements in accuracy and reproducibility can be achieved.

EXAMPLE Hereinafter, an example of the present invention will be described as shown in FIG.
The explanation will be based on 1. Figure 1 (at (bl (cl) is an example of the case where it is applied to the solder heat resistance test, which is one of the mechanical environment tests. First, the solder with temperature control function [ Eri to 7, solder 8
is melted and the semiconductor device 9 is immersed into it. Next, as shown in FIG. 1 fb), the semiconductor device 9 after the solder application test is immersed in a beaker 11 filled with water 10, and the beaker 11 is placed inside a suitable pressure sealing device 12.

Compressed air 1 is supplied to the pressure sealing device 12 through a pressurizing valve 13.
4 is fed into the semiconductor device 9, and elimi water 10 is press-fitted into the semiconductor device 9. Compressed air pressure is 3~4~. The press-fitting time is about 20 minutes. After the press-fitting is completed, the exhaust valve 15 is made to evacuate the air, and the beaker 11 is made and the semiconductor device 9 is taken out. Finally, in Figure 1 (
As shown in C1, in the liquid tank 16 with temperature control function, Eri, 10
The semiconductor device 9 into which water has been press-fitted using the jig 18 is immersed in the liquid 17 set at 0° C. or higher. As a result, air bubbles 19 are formed by pressing the resin portion of the semiconductor device 9. Note that the liquid 17 is stable above the boiling point of water;
Since characteristics such as not having a chemical effect on the semiconductor device @ 9 and being transparent for visual confirmation of bubbles are required, an inert type fluorine liquid (boiled at 230°C) is required.

A setting temperature of 125°C is appropriate. However, if water adheres to the surface of the semiconductor device 9, it will foam when it is immersed in the liquid 17 and cannot be distinguished from the air bubbles 19 from the cracked portion. It is desirable to remove attached water and gold.

In addition, FIG. 1 (cl) also shows a comparison with a semiconductor device 20 in which water was not injected after conducting a soldering heat resistance test under the same conditions.Clear bubbles were seen in the semiconductor device into which water was injected. It can be seen that the reliability of the evaluation results has been improved.Also, after changing the conditions of the soldering heat resistance test (soldering temperature, immersion time, degree of immersion, etc.), water was press-injected and the semiconductor device under each condition was improved. If bubbles are generated, comparing their locations and the duration of the bubbles allows us to understand the thermal shock resistance of the semiconductor device and take measures to improve it. Furthermore, since water is expected to enter from the interface between the lead frame 3 and the resin 5, by evaluating air bubbles from this interface, the adhesion between the two can be easily determined, and the long-term moisture resistance of the semiconductor device can also be evaluated. can.

The above is an example of application to solder heat resistance testing, but it can also be applied to other mechanical environment tests (e.g. vibration, shock, thermal shock tests, etc.) to detect extremely minute cracks that occur as a result. It is possible to achieve significant improvements in certainty, resolution, precision, and reproducibility for evaluation of test results.

Effects of the Invention According to the test method of the present invention described above, cracks in the resin part of semiconductor devices that occur during mechanical environment tests that are difficult to discern with the naked eye can be easily detected by injecting water in a short time at room temperature. The accuracy, precision, and reproducibility of test result evaluations are significantly improved.

In particular, in visual inspection, the evaluation results may lack objectivity, so the test method of the present invention greatly improves the dependence on the measurer.

[Brief explanation of the drawing]

Figure 1 (al (c) is a sectional view showing the test procedure in one embodiment of the test method of the present invention, Figure 2
Machining (BL is a plan view and a cross-sectional view of the semiconductor device after the soldering heat resistance test. 5...Resin, 6...Crack, 7...Solder bath with temperature control function, 8...Solder , 9... semiconductor device, 1
0...Water, 12...Pressure enclosure device, 16...Liquid tank with temperature control function, 17...Liquid, 19...Bubble. Agent Yoshihiro Renmoto 1st Figure 2nd Figure 16 In Masa - Crackoo

Claims (1)

[Claims] 1. After conducting a mechanical environment test on a resin-sealed semiconductor device, water is pressurized into the semiconductor device at room temperature, and then immersed in a liquid at a temperature higher than the boiling point of water to form foam due to the evaporation of water. Test method for resin-sealed semiconductor devices to confirm