Burn-in Board for Reliability Testing

Semiconductor equipment that test and screen out early failures during the “infant mortality” stage are put on a board known as “Burn-in Board”. On a burn-in board, there are multiple sockets to place the semiconductor device (ie. laser diode or photodiode). The number of devices which are placed on a board can consist of low batches of 64 to over 1000 devices at the same time.

These burn-in boards are then inserted into the burn-in oven which can be controlled by an ATE (Automatic Test Equipment) that supplies the mandatory voltages towards the samples while maintaining the desired oven temperature. The electrical bias applied may either be static or dynamic.

Usually the semiconductor components (ie. Laser Diodes) are pushed beyond what they will have to go through in normal use. This ensures that the manufacturer can be confident that they have a robust laser diode or photo diode device and that the component can meet reliability and qualification standards.

Burn-in Board material options:

IS410

IS410 is a high-performance FR-4 epoxy laminate and prepreg system designed to support the printed circuit board industry’s requirements for higher levels of reliability and the trend to use lead free solder.

370HR

370HR laminates and prepregs are made using a patented high performance 180°C Tg FR-4 multifunctional epoxy resin system that is designed for multilayer Printed Wiring Board (PWB) applications where maximum thermal performance and reliability are required.

BT Epoxy

BT epoxy is widely chosen for its outstanding thermal, mechanical, and electrical properties. This laminate is suitable for lead-free PCB assembly. It is primarily used for multilayer board applications. It features excellent electro migration, insulation resistance, and high thermal resistance. It also maintains bond strength at high temperature.

Polymide

BT epoxy is widely chosen for its outstanding thermal, mechanical, and electrical properties. This laminate is suitable for lead-free PCB assembly. It is primarily used for multilayer board applications. It features excellent electro migration, insulation resistance, and high thermal resistance. It also maintains bond strength at high temperature.

Nelco 4000-13

Nelco® N4000-13 series is an enhanced epoxy resin system engineered to provide both outstanding thermal and high signal speed / low signal loss properties. N4000-13 SI® is excellent for applications that require optimum signal integrity and precise impedance control, while maintaining high reliability through CAF 2 and thermal resistance.

Burn-in Board Thickness:

0.062” – 0.125” (1.57 mm – 3.17 mm)

Burn-in Board Applications:

During the burn-in process extreme temperatures often ranging from 125°C – 250°C or even 300°C are applied so the materials used need to be extremely durable. IS410 is used for burn-in board applications up to 155°C and typically a polyimide for applications up to 250°C.

Burn-in boards can be used in environmental testing conditions such as:

HAST (Highly Accelerated Temperature and Humidity Stress)

LTOL (Low Temperature Operating Life)

HTOL (High Temperature Operating Life)

Burn-in Board Design Requirements:

One of the most important considerations is selecting the highest possible reliability and quality for the Burn in Board and the test socket. You don’t want your Burn in board or socket to fail before the device under test. Therefore, all active/passive components and connectors should comply with high-temperature requirements, and all materials and components should meet high-temperature and aging requirements.

Burn-in Chamber

A burn-in chamber is an environmental oven used to evaluates the reliability of multiple semiconductor devices and performs large capacity screenings for premature failure (infant mortality). These environmental chambers are designed for static and dynamic burn-in of integrated circuits (ICs) and other electronic devices such as laser diodes.

Selecting Chamber Size

The chamber size depends on the size of the burn-in board, the number of products in each burn-in board, and the number of batches required per day to meet production requirements. If the interior space is too small, insufficient space between parts results in poor performance. If it is too large, space, time and energy are wasted.

Companies that are purchasing a new burn-in set-up should work with the vendor to ensure the heat source has enough steady-state and maximum capacity to match the load for the DUT.

When using forced recirculating airflow, parts benefit from spacing, but the oven can be loaded more densely vertically because airflow is distributed along the entire side wall. Parts should be kept 2-3 inches (5.1 – 7.6cm) from the oven walls.

Burn-in Chamber Design Specs

Temperature Range

Depending on the requirements of the Device Under Test (DUT) select a chamber that has a dynamic range such as 15°C above ambient to 300°C (572°F)

Temperature Accuracy

It is important that the temperature does not fluctuate. Uniformity is the maximum difference between the highest and lowest temperatures in a chamber at a specified setting. A specification of at least 1% setpoint for uniformity and 1.0°C control accuracy is acceptable in most semiconductor burn-in applications.

Resolution

A high-temperature resolution of 0.1°C will provide the best control to meet burn-in requirements

Environmental Savings

Consider a burn-in chamber that has a refrigerant that has a zero ozone layer depletion coefficient. Burn-in chambers with refrigeration are related to chambers operating in temperatures below 0 degrees Celsius down to – 55°C.

Chamber configuration

The chamber can be designed with card cages, card-slots, and access doors to simplify connecting DUT boards and driver boards with ATE stations.

Chamber Air Flow

In most cases a forced convection oven with recirculating airflow will provide the best distribution of heat and significantly speeds the time-to-temperature and heat transfer to parts. Temperature uniformity and performance depends on a fan design that directs air to all areas of the chamber.

The chamber can be design with a horizontal or vertical airflow. It is important to know the direction of inserting the DUT based on the airflow of the chamber.

Custom ATE Wiring

When it comes to measuring over hundreds of devices, inserting wires through an aperture or test hole may not be practical. Custom wiring connectors can be mounted directly to the oven to facilitate the electrical monitoring of the device with an ATE.

How A Burn-in Oven Controls Temperature

The  burn-in oven uses a temperature controller executing a standard PID (proportional, integral, derivative) algorithm. The controller senses the actual temperature value versus the desired setpoint value, and issues corrective signals to the heater calling for application ranging anywhere from no heat to full heat. A fan is also used to equalize the temperature through the chamber.

The most common sensor used for accurate temperature control of the environmental oven is a Resistance Temperature Detector (RTD) which a platinum-based unit typically referred to as a PT100.

Sizing The Chamber

If you are using an existing oven, basic thermal modelling based on factors such as the oven’s thermal capacity and losses, heat-source output, and DUT mass will allow you to verify that the oven and heat source are sufficient to reach desired temperature with a thermal time constant short enough for tight loop response under the controller’s direction.

Burn-in Testing

Burn-in testing is the process by which a system detects early failures in semiconductor components (infant mortality), thereby increasing a semiconductor component reliability. Normally burn-in tests are performed on electronic devices such as laser diodes with an Automatic Test Equipment laser diode burn-in system that runs the component for an extended period of time to detect problems.

A burn-in system will use cutting-edge technology to test the component and provide precision temperature control, power and optical (if required) measurements to ensure the precision and reliability required for manufacturing, engineering evaluation, and R&D applications.

Burn-in testing may be conducted to ensure that a device or system functions properly before it leaves the manufacturing plant or to confirm new semiconductors from the R&D lab are meeting designed operating requirements.

It is best to burn-in at the component level when the cost of testing and replacing parts is lowest. Burn-in of a board or an assembly is difficult because different components have different limits.

It is important to note that burn-in test is usually used to filter out devices that fail during the “infant mortality stage” (beginning of bathtub curve) and does not take into count the “lifetime” or wearout (end of the bath tub curve) – this is where reliability testing comes into play.

Wearout is the natural end-of-life of a component or system related to continuous use as a result of materials interaction with the environment. This regime of failure is of particular concern in denoting the lifetime of the product. It is possible to describe wearout mathematically allowing the concept of reliability and, hence, lifetime prediction.

What Causes Components to Fail During Burn-in?

The root cause of fails detected during burn-in testing can be identified as dielectric failures, conductor failures, metallization failures, electromigration, etc. These faults are dormant and randomly manifest into device failures during device life-cycle. With burn-in testing, an Automatic Test Equipment (ATE) will stress the device, accelerating these dormant faults to manifest as failures and screen out failures during the infant mortality stage.

Burn-in testing detects faults that are generally due to imperfections in manufacturing and packaging processes, which are becoming more common with the increasing circuit complexity and aggressive technology scaling.

Burn-in Testing Parameters

A burn-in test specification varies depending on the device and testing standard (military or telecom standards). It usually requires the electrical and thermal testing of a product, using an expected operating electrical cycle (extreme of operating condition), typically over a time period of 48-168 hours. The thermal temperature of the burn-in test chamber can range from 25°C to 140°C .

Burn-in is applied to products as they are made, to detect early failures caused by faults in manufacturing practice.

Burn In Fundamentally performs the following:

Stress + Extreme Conditions + Prolong Time = Acceleration of “Normal/Useful life”

Types of Burn-in Tests

Dynamic Burn-in :  the device is exposed to high voltage and temperature extremes while being subjected to various input stimuli .

A burn-in system applies various electrical stimuli to each device while the device is exposed to extreme temperature and voltage. The advantage of dynamic burn-in is its ability to stress more internal circuits, causing additional failure mechanisms to occur. However, dynamic burn-in is limited because it cannot completely simulate what the device would experience during actual use, so all the circuit nodes may not get stressed.

Static Burn-in : Device under test (DUT) is stressed at elevated constant temperature for an  extended period of time.

A burn-in system applies extreme voltage or currents and temperatures to each device without operating or exercising the device. The advantages of static burn-in are its low cost and simplicity.

How is a Burn-In Test Performed?

The semiconductor device is placed onto special Burn-in Boards (BiB) while the test is executed inside special Burn-in Chamber (BIC).

Know more about Burn-in Chamber（Click here）

Clean Dust-free Oven

Clean oven is also known as dust-free oven, mainly using the air filter to purify the environment and avoid fine particles in the air into the chamber. The air inside the chamber is closed and self-circulating, which is repeatedly filtered by the 100-class high temperature and high efficiency air filter, so that the working room is in a dust-free state. The dust-free oven is suitable for pre-treatment baking of silicon wafer, gallium arsenide, lithium niobate, glass and other materials before gluing, hard film baking after gluing and high temperature baking after developing in semiconductor manufacturing. It is also suitable for electronic liquid crystal display, LCD, CMOS, IS, medicine, laboratory and other production and scientific research departments; In addition, the dust-free industrial oven can be used for drying, heat treatment, aging and other high temperature tests of non-volatile and non-flammable and explosive items.

Features of dust-free oven:

1. Structure: the structure of dust-free oven is reasonable, assembled by the box part, the electrical control cabinet, the electric heating and the air duct circulation system.

2, Sealing design: surrounded by argon welding, using high temperature silicone rubber dust-free sealing strip heat insulation, to ensure tightness and cleanliness;

3, External dust treatment: the external material is SPCC steel plate after powder spraying plastic, wear-resistant dust and slag;

4, High efficiency filter: HEPA filter structure clean room, 99.99% effective filtration, cleanliness reached grade 100;

5, Energy saving: insulation material for high-density fiber, heat preservation and energy saving;

6, Layered structure design: the height of the internal chamber layer can be adjusted and freely taken out;

7, Temperature control instrument: automatic control of temperature, constant temperature and time control, setting with over temperature automatic power outage and alarm circuit for reliable control and safe use.

8, Electrical accessories: all use the first-line brand, PID calculus temperature control system and overtemperature protection device, intelligent constant temperature, small temperature difference, suitable for different products of long and short baking.

Product parameters of dust-free oven:

1, Temperature range: from normal temperature to 250℃, constant temperature adjustable

2, External size: H1660*W770*D920mm; internal size: H900*W600*D600mm

3, Heating speed: from room temperature to 200℃ in about 30 minutes

4, Insulation performance: the outer wall temperature of the chamber does not exceed 45℃ (when the temperature inside the chamber reaches 200℃)

5, Temperature control accuracy: ±1℃

6, Temperature uniformity: ±3℃%

7, The use of power supply: 380V/50HZ (3 ∮ 5 wire)

Clean Hot Air Circulation Oven

Hot air circulation oven is a universal drying equipment with a long history, which has a wide range of application, uniform temperature, high thermal efficiency and simple operation. It is one of the necessary drying equipment for most pharmaceutical and related enterprises, and is also a popular drying equipment for users.

Based on years of actual production experience and existing production technology, combined with the current national pharmaceutical industry GMP requirements, our company designed the oven that is higher than the current national GMP standard requirements for the pharmaceutical industry - clean oven, its technical characteristics are described as follows:

1, Equipment materials: internal and external walls are SUS304 stainless steel, the internal cavity is full of welding, rounded transition, making the oven without wind phenomenon in the working state, and making the equipment easy to clean, no water seepage phenomenon in the heat preservation layer, to ensure that the cleanliness of the items dried each time. The external wall is made of brushed board making the outer surface of the oven is flat, smooth, beautiful, no visible concavity and convexity;

2, Circulating fan impeller, volute shell are made of stainless steel, to ensure clean circulating air; selection of large air volume, high air pressure centrifugal fan as a circulating fan for forced ventilation, which can speed up the drying speed of the material to ensure the uniformity of material drying.

3, The drying oven air inlet is divided into two levels of filtration, the new air inlet for the intermediate filter, making the new air up to 300,000, after heating each cycle of hot air with high-temperature high efficiency filter filtration, so that the hot air into the drying oven are more than 10,000 levels of cleanliness, to ensure that the drying process of cleanliness;

4, The system is equipped with all stainless steel moisture exhaust fan, and the system's PLC program module collects the humidity in the system for intelligent control: According to the signal provided by the humidity control instrument, the damper actuator of the humidification port is controlled by the damper. At the same time, the damper is controlled by the frequency converter to output the corresponding frequency according to the size of the humidity signal, and the reasonable air volume is discharged to achieve the best humidification effect and achieve reasonable humidification. The moisture outlet is equipped with a medium effect filter to ensure the cleanliness of the return air of the moisture outlet.

5, Oven heating form: steam or electric heating. The material is stainless steel. Its has good heat dissipation effect and sanitary conditions. The fluctuation range is about ±1℃;

6, The circulatory system stroke from both sides of the main machine into the same time, concentrated to the middle exhaust air, compared with the conventional design to reduce the temperature difference between the left and right sides of the oven; According to the guiding rules of the air volume and air pressure of the air inlet and air outlet, multiple groups of punching plates with different ratios are designed as the distribution device of the inward hot air to achieve a smaller temperature difference. Moreover, the fixing method of the air equalizing network board and the main engine adopts the quick fixing method, which can quickly clean the inlet and outlet air duct to ensure the cleanliness of the chamber;

7, The equipment is designed with 5 sewage outlets in the air inlet, skip and air outlet, which can ensure that all the sewage is discharged quickly after cleaning. The five sewage outlets are gathered into a main pipe for centralized discharge, reducing the total sewage outlet, so that the plant can open less floor drains;

8, The equipment in the inlet and outlet duct design can cover the entire system of 7 online cleaning ports, in normal circumstances to achieve fast and simple online cleaning function, can also be directly set up online cleaning device, in order to achieve the true meaning of CIP;

9, The oven track is convex splints, and the bottom plate is connected by round foot welding, and the drying car is equipped with inclined pedal, which makes the drying car easy to enter and exit; At the same time reduce the dead Angle without affecting the blowdown performance; Stainless steel square tube is used for the column and stainless steel Angle steel is used for the beam of the oven, and argon arc welding is adopted. Wheels with high temperature resistant nylon wheels, each dryer with 2 directional wheels, 2 steering wheels. The whole dryer has reasonable structure, high strength, beautiful and practical;

10, The equipment heating system (heater, high temperature and high efficiency filter) is concentrated in the closed stainless steel chamber, good insulation effect, high cleanliness, and high temperature and high efficiency filter for the drawer type fast loading structure, can be cleaned and replaced quickly; The connecting parts and the system are connected with the adjustable screw quick installation design, which is convenient for maintenance and overhaul;

11, The oven door lock adopts advanced adjustable elastic door lock, good locking performance, easy to operate. High temperature and non-toxic silicone rubber sealing ring is used between the door and the box, which has excellent sealing performance. The insulation layer of the oven adopts ultra-fine glass wool, which has good thermal insulation performance.

12, All the round flanges in the system are connected by quick-opening clamp, and the method is designed by quick-mounting butterfly screws, which facilitates the disassembly and cleaning of the pipeline;

13, There are two quick verification ports on the equipment host, which is convenient to verify the temperature and humidity during the working process.

Environmental Test Solutions for Electronic Products

The statistical analysis shows that the failure of electronic components accounts for 50% of the failure of electronic complete machine, and the reliability detection technology still faces many challenges.

Environmental Test Solutions For Mechanical And Electrical Products

The statistical analysis shows that the failure of electronic components accounts for 50% of the failure of electronic complete machine, and the reliability detection technology still faces many challenges.

Environmental test Solutions for Vehicle Transport Auto Parts

The reliability of vehicle transportation auto parts products is very important, which directly determines the safety, reliability and operation comfort of the vehicle.

High and Low Temperature Low Pressure Test Equipment & Rapid Decompression Device

High and low temperature low pressure test chamber：

(1). Main technical indicators

1. Studio size: 1000D×1000W×1000H mm, the internal size is about 1000L

2. External size: about 3400D×1400W×2010H mm, excluding the controller, test hole and other prominent parts.

3. Temperature range: -70℃ ~ +150℃

4. Temperature fluctuation: ≤±0.5℃, normal pressure, no load

5. Temperature deviation: ±2℃, normal pressure, no load

6. Temperature uniformity: ≤2℃, atmospheric pressure, no-load

7. Heating rate: +20℃→+150℃≤60min

8. Cooling rate: +20℃→-65℃≤60min

9. Humidity range: Humidity 20% ~ 98%RH (temperature +20℃ ~ +85℃ range)

10. Humidity deviation: ≤+ 2-3%RH (> 75%RH), ≤±5%RH(≤75%RH), under normal pressure and no-load conditions.

11. Pressure range: normal pressure ~ 0.5kPa

12. Pressure reduction rate: normal pressure ~ 1.0kPa≤30min

13. Pressure recovery rate: ≤10.0kPa/min

14. Pressure deviation: normal pressure ~ 40kPa:≤±2kPa, 40KPa ~ 4kPa:≤±5%kPa, below 4kPa:≤± 0.1kPa

15. Wind speed: frequency conversion adjustment

16. Power: about 50kW

17. Noise: ≤75dB (A), 1 meter away from the front of the chamber and 1.2 meters above the ground.

18. Weight: 1900Kg

(2). Rapid decompression device (optional)

In order to meet the requirements of rapid depressurization, an independent rapid depressurization chamber is processed. The rapid depressurization chamber is composed of a shell assembly, a pressure assembly, a door assembly, an interface and a moving frame. Before rapid decompression, the user needs to connect an external pipeline.

1. Studio size: 400mm deep x 500mm wide x 600mm long; The internal wall material is processed with 3.0 SUS304/2B, and 5mm square pipe is used as the pressure reinforcement.

2. External dimension: 530mm deep ×700mm wide ×880mm long, the external wall material is made of 1.2mm cold-rolled steel plate, the surface is sprayed white (consistent with the color of the chamber);

3. A pressure sensor port is reserved at the top of the container. The control sensor port is located at the rear of the container to facilitate the quick buck device to be routed.

4. For the convenience of moving fast buck device. Install four lifting casters under the frame; The moving frame is welded by ordinary steel and sprayed on the surface.

5. Rapid decompression process: In order to improve the pumping speed of rapid depressurization chamber, the test chamber is first pumped to about 1kPa, and the electric valve connecting the test chamber equipment and the fast reducing device is opened to realize the fast reducing function, and the valve is closed when it reaches 18.8kPa. The constant pressure in the fast relief chamber can be achieved by auxiliary pumping (intake valve).

(3). Product implementation standards

1. GB/T2423.1-2008 Test A: Low temperature test

2. GB/T2423.2-2008 Test B: Low temperature test

3. GB/T 2423.3-2006 test Cab: constant temperature and humidity test

4. GB/T 2423.4-2008 test Db: alternating temperature and humidity test

5. GB/T2423.21-2008 Test M: Low pressure test method

6. GB/T2423.25-2008 test Z/AM: Low temperature/low pressure comprehensive test

7. GB/T2423.26-2008 Test Z/BM: high temperature/low pressure comprehensive test

8. General requirements for GJB150.1-2009

9. GJB150.2A-2009 Low pressure (altitude) test

10. GJB150.3A-2009 high temperature test

11. GJB150.4A-2009 low temperature test

12. GJB150.6-86 temperature-height test

13. GJB150.19-86 Temperature - humidity - height test

14. DO16F rapid decompression test

15. GB/T 10586-2006 temperature and humidity test chamber technical conditions

16. GB/T 10590-2006 high temperature low pressure test chamber technical conditions

17. GB/T 10592-2008 high and low temperature test chamber technical standard

18. GB/T 5170.1-2008 General Rules for inspection methods of environmental test equipment for electrical and electronic industry

19. GB/T 5170.2-2008 Electrical and electronic products environmental test equipment test method temperature and humidity test equipment

20. GB/T 5170.5-2008 Electrical and electronic products environmental test equipment test method temperature and humidity test equipment

GB/T 5170.10-2008 Electrical and electronic products environmental test equipment test method high temperature low pressure test equipment

Information Communication Environment Test Solution

The statistical analysis shows that the failure of electronic components accounts for 50% of the failure of electronic complete machine, and the reliability detection technology still faces many challenges.