JPS61209366A - Method for testing reliability of resin sealed type semiconductor apparatus - Google Patents

Abstract

PURPOSE:To make it possible to shorten a reliability testing time and to enable the detection of a fine flaw, by applying two kinds of liquid penetration treatment and liquid evaporation treatment to a mold element prior to conducting the reliability test of said mold element. CONSTITUTION:A mold element 1 is immersed in molten solder 13 for a predetermined time and the liquid penetrated in the surface of a chip by this treatment is exposed to high temp. of b.p. or more to be instantaneously evaporated At this time, said element 1 generates abrupt volumetric expansion but, because the surface of the chip is molded from a resin material, said volumetric change can not be escaped to the outside and said liquid comes to high pressure gas to collectively apply evaporation pressure to the flow area, especially, a pinhole or minute crack area of the protective film on the surface of the chip and said flaw area is enlarged or destructed. At the same time, an impurity ion is thrown into the flaw under high pressure. When thus pretreated mold element 1 is adapted to a reliability test, the promotion or destruction of the pretreated flaw part or the generation of trouble due to the impurity ion thrown into the flaw part consciously becomes fast and the shortening of a test time or the discovery of fine trouble is enabled.

Description

[Detailed Description of the Invention] Industrial Field of Application The present invention relates to reliability testing of resin-sealed semiconductor devices (hereinafter abbreviated as molded elements), specifically, reliability testing that involves accelerated deterioration of the molded elements. It is about the method.

BACKGROUND OF THE INVENTION Conventionally, completed molded devices have been tested as they are in accordance with reliability testing methods standardized by JIS and the like. In this case, durability tests and environmental tests are mainly conducted, and the main purpose is shown in Figure 6.

This will be explained with reference to FIG.

FIG. 6 shows a cross-sectional view of a molded element taking a semiconductor integrated circuit device (IC) as an example, where 1 is the molded element body, 4 is a lead wire, 5 is a lead frame, and 6 is an I (
j chip, 7 is molded resin fi, IC chip part 6
Figure 6 shows an enlarged version of the figure. In FIG. 6, 4 is a lead wire from the IC chip, 8 is a vapor-deposited metal wiring, and 6
9 is an IC chip substrate, 9 is a protective film %1o is an insulating film, and 7 is a resin material so as to cover all of the above.

In the reliability test, there was a deterioration in characteristics due to impurity ions that entered the local part 9 of the protective film 9, disconnection of the electrode wiring 8 due to impurity ions that entered the other local part 9B, and lead wire 4.
and contact deterioration of the vapor-deposited metal wiring 8 have been tested through durability tests and environmental tests such as high-temperature actual operation durability tests, high-temperature reverse bias durability tests, high-temperature and high-humidity bias tests, and high-temperature and high-humidity storage tests.

Problems to be Solved by the Invention In such conventional testing methods, as the failure rate has decreased due to improvements in materials and construction methods, the testing time has become longer and it has been difficult to detect minute defects at an early stage.

The present invention was made to improve these drawbacks, and aims to provide a method for detecting minute defects and shortening test time by introducing a simple pretreatment method.

Means for Solving the Problems In order to achieve the above-mentioned object, the present invention provides a method of exposing to high humidity under atmospheric pressure or high pressure or immersing in a solution under high pressure immediately before conducting a reliability test. After infiltrating the chip surface with a liquid, heat treatment is performed to a temperature above the boiling point of the liquid, and the vaporization pressure of the liquid is used to enlarge minute defects on the chip surface and impurity ions are forced into the defects using high pressure. This process performs the process of pushing the

Effect of the Invention With the above-described configuration, the present invention can detect minute defects on the chip surface and significantly shorten the reliability test time by combining pretreatment and conventional reliability testing methods.

Embodiment Next, an embodiment of the present invention will be explained with reference to the block diagram shown in FIG.

In FIG. 1, a liquid infiltration process and a liquid vaporization process are performed on the molded element 1 in advance, preferably immediately before the actual reliability test is performed.

In the liquid immersion process, the mold element 1 is exposed to high humidity under atmospheric pressure or high pressure, or immersed in a solution under high pressure, so that water vapor or solution intentionally penetrates into the chip surface. In this case, the appropriate high humidity conditions are 85°C, 196% RH, and steam pressurization (4 atm, 142°C, 100% RH), and the liquid immersion conditions include immersion in a solution (alcohol, etc.) and high pressure gas ( Set appropriate conditions such as infiltration under H gas (4 atmospheres).

FIG. 2 is a schematic cross-sectional view of an example of equipment for setting high humidity conditions.
This is what was saved on 2. In this case, the mold element 1 is as shown in FIG.
It penetrates through the interface between the lead wire 4 and the resin 7, and reaches the surface of the IC chip 6 along the interface between the lead wire 4 and the resin 7. The processing time is set appropriately based on the processing method 9 conditions.

In Figure 1, after the liquid infiltration process is performed, the liquid is vaporized, but in this case, it is necessary to heat the liquid to a temperature higher than the boiling point of the infiltrated solution, and it is necessary to heat the liquid to a temperature that is as rapid as possible. It is desirable to take. The heating means is 70 Rocarbon.

Any suitable method may be used, such as direct immersion in a high-temperature liquid such as silicone oil or molten solder, or exposure to a high-temperature atmosphere such as heating with a heater or infrared heating. The former, that is, direct □ immersion in high-temperature liquid is preferable.

FIG. 3 shows a process explanatory diagram of one embodiment.

13 is molten solder, for example 260. The mold element 1 is directly immersed in a lead-tin alloy solder bath of 'C for 30 seconds. The processing temperature and processing time may be appropriately set depending on the type of resin, the circuit performance of the chip, etc.

Through this process, the liquid that has penetrated the chip surface is exposed to high temperatures above the boiling point and instantly vaporizes. At this time, a rapid volumetric expansion occurs, but since the bottom of the chip is molded with a resin material, this change cannot escape and becomes a high-pressure gas, causing pinholes and minute cracks in the protective film on the chip surface. Vaporization pressure is applied intensively to areas where there are defects, enlarging or destroying these defective areas. At the same time, impurity ions are forced into these defects at high pressure. When this is dealt with using the molded element shown in FIG. 6, the liquid adhering to the surface of the protective film 9 is heated to a high temperature and becomes a high-pressure gas, and in the local parts 9 and 9B of the protective film 9, Focus on weak areas of the membrane to enlarge or destroy these defects. For example, if the weak part of the local part 9B of the same litter is accelerated or destroyed, it will lead to electrode wiring deterioration and disconnection, and if the weak part of another local part 9 is accelerated or destroyed, the V of the MO3 type semiconductor device, This leads to fluctuations in characteristics such as h□ and h□ of bipolar semiconductor devices. Further, strong gas pressure is applied not only to the surface of the protective film 9 but also to the interface between the wire 4 and the electrode wiring 8, thereby accelerating the deterioration of the contact portion.

When a molded element pretreated through the above process is applied to a reliability test, failures are significantly more likely to occur due to the acceleration or destruction of defective parts caused by the pretreatment and the intentionally introduced impurity ions. This makes it possible to shorten the test time. Furthermore, it becomes possible to discover minute failures that could not be detected conventionally.

FIG. 4 shows a comparison of the results of a high temperature, high humidity bias test and a high temperature operation durability test performed on mold elements with and without the pretreatment of the present invention. It is a Weibull chart in which the vertical axis represents the cumulative number fi100 percent and the horizontal axis represents the test time.

In the figure, M' and M' are the results of a durability test using 160°C actual operation, and B and B' are the results of a high temperature, high humidity bias test at 86°C and 185% RH.The test conditions for each are the results of a reliability test. Generally adopted. Among the test results,
Person B, indicated by the solid line, shows an example in which the molded element was stored for 20 hours under a saturated water vapor pressure of 3 atm, and then immersed in molten solder at 260°C for 30 seconds, and Person B indicated by the broken line. ', B' indicate those not subjected to these treatments.

As is clear from this figure, both M and B, which are shown by solid lines that have been pretreated, have a higher failure rate than A' and B', which are not pretreated and are shown by broken lines, indicating that the test time can be shortened. There is.

Effects of the Invention As is clear from the above explanation, according to the present invention, before a reliability test is performed on a molded element, pretreatment is performed using two types of treatment: liquid immersion treatment and liquid vaporization treatment. It is practical and extremely useful as a method for shortening reliability tests and detecting minute defects.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing an embodiment of the present invention;
Fig. 2 is a schematic sectional view of the equipment showing an example of liquid immersion processing according to the present invention, Fig. 3 is an explanatory diagram of the molten solder immersion process also showing an example of liquid vaporization processing, and Fig. 4 is a diagram for explaining the details of the present invention. Wiple chart showing the high temperature actual operation durability test results and high temperature high humidity bias test results, Figure 5 is resin sealing carving C
FIG. 6 is an enlarged sectional view of the vicinity of the IC chip shown in FIG. 1...Mold element, 4...Lead wire, 6...Lead frame, 6...
IC chip, 7...Mold resin, 8...
...Vapour-deposited metal wiring, 9...Protective film, 10...
...Insulating film, 12...High pressure solution, 13...
...Melted solder. Name of agent: Patent attorney Satoshi Nakao, 11th son, and 1 other person Figure 1 Figure 2 Figure 4 η Figure 3 Weibltepet t (/LγS)-111 5-m- Word 7 Reim No. 6rIA 4-1-ν- Dofuiya 5--Wa) ``7 Reimu''

Claims (1)

[Claims] Immediately before carrying out durability tests and environmental tests on resin-sealed semiconductor devices, the chip surface is exposed to high humidity under atmospheric pressure or high pressure, or immersed in a solution under high pressure to infiltrate the chip surface with liquid. 1. A method for testing the reliability of a resin-sealed semiconductor device, the method comprising: heating the liquid, and then performing a heat treatment, and detecting minute defects using the vaporization pressure of the liquid.