Electronic Components Aging Test

In electronic products the processing process, due to the complex processing and component materials experienced a large number of uses, both processing defects and component defects can be divided into obvious defects and potential defects, obvious defects refer to those defects that lead to the product can not work properly, such as short circuit / broken circuit.

Electronic Components

Potential defects lead to products that can be used temporarily, but the defects will be quickly exposed in use and the product will not work properly. Potential defects, on the other hand, cannot be detected by conventional inspection means, but are rejected by applying aging methods.

If the aging method is ineffective, potential defects that are not removed will eventually manifest themselves in the form of early failures or malfunctions during the product’s operation, leading to increased product return rates and increased maintenance costs.

 

1、Concept

Aging refers to a certain ambient temperature, a longer period on the components of the continuous application of environmental stress, and environmental stress screening includes not only high-temperature stress but also many other stresses, such as temperature cycling, random vibration, etc., through the combined effect of electrical and thermal stress to accelerate a variety of physical and chemical reaction processes within the components, to promote the hidden in the internal components of a variety of potential defects exposed as early as possible, so that the purpose of eliminating early failure products. To achieve the purpose of eliminating early failure products. Aging is a kind of environmental stress screening.

 

2、Role

① For a series of defects that may exist in the process of manufacturing, such as surface staining, poor lead welding, channel leakage, wafer cracks, oxide layer defects, and local hot spots have a better screening effect.

② For components without defects, aging can also promote the stability of its electrical parameters.

 

3、Aging test items

The main aging test items are:

3.1 Light aging test:

Light aging is the main outdoor use of materials subjected to aging damage, for indoor use of materials, will also be subjected to a certain degree of light aging. Simulation of light aging of the main three lamps has its advantages, The carbon arc lamp was first invented to use, the establishment of the measurement system earlier, many Japanese standards and fiber materials standards use carbon arc lamps, but due to the high price of carbon arc lamp, the performance is not stable enough (90 hours after the use of lamps need to be replaced), has gradually been replaced by xenon arc lamps, ultraviolet lamps. Xenon lamps have a greater advantage in simulating natural light, the price is relatively low, suitable for most products.

UV lamps produce light below 400nm, can better accelerate the simulation of natural light in the ultraviolet ray on the destruction of materials, the acceleration factor is higher than xenon lamps, the stability of the light source than xenon lamps, but prone to non-natural light output of the destruction (especially UVB lamps).

UV Aging Tester (2)

Main applications: outdoor, and indoor use of rubber and plastic, paint, ink products, communications, electrical and other equipment shells, automotive parts, motorbike parts.

3.2 Thermal aging

Main reference standards:  ASTM D3045, JIS K 6257, and so on.

The heat aging box has the function of procedure, and the temperature change can be set through the procedure, which is suitable for the needs of heat aging of various products.

Main application scope: heat-resistant aging test of various products, such as PCB boards, electrical appliances in the insulating rubber, long-life demand for products (such as cable-stayed bridges with the jacket material, the use of more than 20 years), etc., to examine the material with the use of time, the change in product performance conditions, and to examine the reliability of the product use.

3.3 Damp heat aging

The main reference standards: are general standards such as GB/T 15905, and GB/T 2573.

In addition, can also be set according to different product standards, enterprise standards of humidity, and temperature change curves, suitable for a variety of complex thermal aging tests. During the use of the product, it is easy to be affected by both temperature and humidity. For some water-sensitive materials, such as PET, PBT, etc., it is necessary to carry out the humid-heat aging test to assess whether it is suitable for long-term use in a humid environment.

3.4 Salt spray aging

Main reference standards: ASTM D117, JISZ2371, and other standards.

Neutral salt spray, acid salt spray, copper ion accelerated salt spray test. Mainly used to simulate the atmosphere dissolved in water vapor sodium chloride on the coating, plating, and other protective procedures and the corrosive effect of metal floor materials, especially in coastal areas and inland salt lakes around the region, the air salt is high, the product is very easy to be corroded by salt spray.

Mainly applicable products: all kinds of coatings, such as building exterior coatings, marine coatings, container coatings, etc., and all kinds of plating.

3.5 Ozone aging

Main reference standards: HG/T 2869, JIS K 6259, ASTM D 1149.

It mainly examines the ozone-resistant performance of rubber (rubber contains a large number of double bonds, which are easy to be attacked by ozone, especially when it is used dynamically or stretched, the ozone damage to rubber is more serious), and also examines the ozone-resistant performance of new elastomers such as TPU, EPDM, and so on.

3.6 High and low-temperature cycle

Main reference standards: JG/T 25 architectural coatings coating freeze-thaw cycle resistance determination method and other standards, can be by different product standards, on the high and low-temperature cycle, freeze-thaw cycle of the relevant test methods to carry out the test. It is mainly used for the testing of architectural coatings and special environmental use equipment.

 

4、Electronic components aging test precautions

To achieve satisfactory results in aging, the following points should be noted:

① The aging equipment should have good measures to prevent self-excited oscillation.

② When applying a voltage to the device, it should be increased slowly from zero and reduced slowly when de-voltage, otherwise the instantaneous pulse generated by the sudden change of power supply voltage may damage the device. After aging, measurements should be made promptly within the time specified in the standards or specifications, otherwise, certain parameters that are out of specification during aging will return to their original values.

③ To ensure that the transistor can be aged at the highest junction temperature, the transistor thermal resistance should be measured accurately.

For integrated circuits, due to their operating voltage and operating current being subject to greater restrictions, their junction temperature rise is very little, such as not improving the ambient temperature which makes it difficult to achieve the temperature required for effective aging. Therefore, room temperature static power aging is only applied to some integrated circuits (linear and digital circuits).

 

5、 Semiconductor devices commonly used in aging screening methods

5.1 Room temperature static power aging

Room temperature static power aging is to make the device at room temperature aging. Semiconductor PN junction is in a positive bias conduction state, the thermal stress required for device aging, is converted from the power consumed by the device itself. As the device is in the aging process due to the combined effects of electricity and heat, the device’s internal physical and chemical reaction process is accelerated, prompting its potential defects exposed in advance, so that the defective device is removed. This aging method does not require high-temperature equipment, the operation is also very simple, so it is commonly used. In the safe range of the device, the appropriate increase in aging power (increase the device junction temperature) can receive better-aging results and can shorten the aging time.

To make the aging achieve satisfactory results, one should pay attention to the following points:

① Aging equipment should be a good measure to prevent self-excited oscillation.

② When applying a voltage to the device, the voltage should be increased slowly from zero, and the voltage should be reduced slowly, otherwise the instantaneous pulse generated by the sudden change of power supply voltage may damage the device. After aging, measurements should be made in time within the time specified in the standard or specification, otherwise, certain parameters that are out of specification during aging will return to their original values.

③ To ensure that the transistor can be aged at the highest junction temperature, the transistor thermal resistance should be measured accurately.

transistors

For integrated circuits, due to their operating voltage and operating current being subject to greater restrictions, their junction temperature temperature rise is very little, such as not improving the ambient temperature which makes it difficult to achieve the temperature required for effective aging. Therefore, room temperature static power aging is only applied in some integrated circuits (linear and digital circuits).

5.2 High-temperature static power aging

High-temperature static power aging of the charging method and test circuit form are the same as the room temperature static power aging, the difference is that the former is in a higher ambient temperature. As the device is at a higher ambient temperature for aging, the junction temperature of the integrated circuit can reach a very high temperature. Therefore, in general, the integrated circuit of high-temperature static power aging effect than room temperature static power aging is better.

Some military electronic component standards specify the integrated circuit to high-temperature static power aging, the specific conditions are: in the product standard rated supply voltage, rated load, signal, and line under the aging. Aging conditions are 125 ± 3 ℃, 168 h (can be determined as needed). The aging process is monitored at least once every 8 hours.

High-temperature reverse bias aging

In high-temperature reverse bias aging, the PN junction of the device is subjected to both high-temperature environmental stress and reverse bias piezoelectric stress, and there is no current or only a small current passing through the device, with almost no power consumption. This aging method is particularly effective in rejecting early failure devices with surface effect defects and is therefore widely used in the aging of semiconductor devices for some reverse applications.

High-Temperature Dynamic Aging

High-temperature dynamic aging is mainly used for digital devices, this aging method is driven by a pulse signal at the input of the aging device, so that the device is constantly in the flip-flop state. This aging method is very close to the actual use of the device.

High-temperature dynamic aging has two basic test circuits: series switching and parallel switching test circuits.

A series switching test circuit is also known as the ‘ring counter’ circuit. Its characteristics are: all the outputs and inputs of the device under test are connected in series to form a ring counting circuit. As the output of the former level is the input of the latter level, that is, the latter level is the load of the former level, which does not require additional excitation signals and additional loads, the equipment is simple and easy to implement. The disadvantage is that any one of the test device failures will make the whole ring system stop working, so the test. Until replaced with a new test circuit or short the problematic device is, the test is back to normal.

The parallel switching test circuit is characterized by the device under test being connected in parallel with the excitation power supply, so each device under test can be driven individually by the applied switching voltage, the output of each device under test can be connected to an analog maximum value of the load, thus overcoming the shortcomings of the series switching aging.

High-temperature dynamic aging test conditions are generally in the highest-rated operating temperature and the highest-rated operating voltage aging 168 ~ 240 h. For example, civilian devices usually a few hours, military high-reliability devices can choose 100 ~ 168 hours, and aerospace-grade devices can be selected for 240 hours or even longer cycles.

 

6、The aging of components

① Resistive components aging test generally by the requirements of the specification to impose the power and temperature environment, special attention should be paid to the aging of whether there is a requirement for heat dissipation.

② Capacitor aging test generally uses high-temperature voltage aging. This method is: in the capacitor’s highest rated operating temperature under the application of rated voltage for 96 ~ 100 h, to weed out the products due to defects in the medium caused by breakdown and short-circuit. For example, organic film capacitor dielectric pinholes, defects, and conductive particles in high-temperature voltage aging will lead to short-circuit failure of the capacitor; liquid tantalum electrolytic capacitors with serious defects in the high-temperature voltage aging, the short-circuit current flowing through the defects is very large, so that the temperature of the product rises suddenly. The electrolyte and solder rapidly vaporize, causing the pressure to reach a level sufficient to destroy the product.

For capacitors without potential defects, high-temperature voltage aging eliminates internal stresses in the product, improves dielectric properties, and increases the capacity stability of the capacitor. High-temperature voltage aging can make the dielectric defective metallized paper dielectric (or plastic foil film) capacitors produce ‘self-healing’, to restore its performance.

 

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