Test Analysis & Equipment Utilization

Physical & Mechanical Environmental Test

Mechanical Shock Test is a test performed to determine the ability of semiconductor devices mounted on printed circuit boards as well as components and assembled parts to withstand moderately severe shocks resulting from suddenly applied forces or abrupt changes in motion encountered during mishandling, improper transportation, or field operation.
As for components, this test is to evaluate the compatibility of a product under the specified shock and as for assembled parts to evaluate changes in motion encountered by repeated physical shock. This is a destructive test to evaluate the resistance of a device to external shock.

Summary of Mechanical Shock Test

Mechanical Shock Test is subject to the following three conditions: maximum shock pulse, pulse duration (width), and shock pulse.

  • The maximum pulse means maximum acceleration applied to the device and the error range is within 10%.
  • The pulse width shall be measured between the 10% point of the peak acceleration during rise time and the 10% point during decay time and the error range is within 15%.
  • The shock pulse means the total amount of waves measured at the maximum shock pulse and the error range is within 10%.

During testing, the device must be rigidly mounted or restrained by its case or body, with ample protection for the leads. The samples shall be subjected to 5 shock pulses for each orientation (total 30 shock pulses),
with the peak intensity and duration of the pulses complying with those defined by the specified test condition, in each of the following orientations: +X, -X, +Z, -Z, +Y, and -Y. (Service condition 1)
In case of assembled parts, when bending is required by shock impulses, the samples shall be subjected to 12 shock pulses, two each for six orientations: +X, -X, +Z, -Z, +Y, -Y. (Service condition 2).

Service Condition Max. Level Pulse duration Shock Pulse Drop Height
g ms cm/s in/s cm inches
H 2900 0.3 543 214 150 59
G 2000 0.4 499 197 127 50
B 1500 0.5 468 184 112 44
F 900 0.7 393 155 78.9 31
A 500 1.0 312 123 49.7 20
E 340 1.2 255 100 33.1 13
D 200 1.5 187 73.7 17.9 7
C 100 2.0 125 49.2 7.90 3

[Service condition 1] When direct shock pulses are applied to the surface of components (unit element) and assembled parts.

Service Condition Max. Level Pulse duration Shock Pulse Drop Height
g ms cm/s in/s cm inches
1 109 8.0 544 214 151 60
2 108 7.5 506 199 130 51
3 107 7.0 468 184 111 44
4 105 6.5 426 168 92.6 36
5 103 6.0 386 152 75.9 30
6 95 5.8 344 135 60.3 24
7 86 5.6 301 118 46.1 18
8 72 5.4 243 95.6 30.0 12
9 67 5.3 222 87.3 25.1 10
10 61 5.2 198 78.0 20.0 8
11 54 5.1 172 67.7 15.1 6
12 45 5.0 140 55.3 10.1 4
13 39 5.0 122 47.9 7.6 3
14 32 5.0 100 39.3 5.1 2

[Service condition 2] When shock pulse-induced warpage is applied to assembled parts.

Mechanical Shock Test Equipment
Mechanical Shock Test Equipment
Test condition B : 1500ºC 0.5ms pulse shape
Test condition B : 1500ºC 0.5ms pulse shape

Reference Documents

  • JESD22-B110B “Mechanical Shock – Component and Subassembly”
Board Level Drop Test is performed with mechanical shock test equipment according to the similar procedures employed in Mechanical Shock Test. This test is to analyze solder joints with test board and other preparations specified and daisy chains provided. Drop test facilitates continuous quality monitoring and the results can be used as useful data in relation to failure data. As Pb-free circuit boards are used, SJR reliability has been issued. This test is required for mobile and electronic components fields. After fifteen components are surface-mounted on specified eight boards, apply stress to them at specified peak acceleration, pulse duration, velocity change, etc. In case of standard conditions for mobile products, peak acceleration is 1500G and pulse duration is 0.5ms of pulse shape.

Summary of Drop Test

Service
Condition
Equivalent drop height
(inches/cm)
Velocity Change
(in/s, cm/s)
Acceleration
Peak (G)
Pulse duration
(ms)
B 44 / 112 184 / 467 1500 0.5

Reference Documents

  • JESD22-B111 “Board Level Drop Test Method of Components for Handheld Electronic Products”
Standard Board mounted on Drop Table
Standard Board mounted on Drop Table

Vibration Tests are tests performed to determine the effects of mechanical vibration within a specified frequency range on semiconductor devices. There are two military standards that are widely used for this purpose:

1) The Vibration Fatigue Test, as defined by Mil-Std-993 Method 2005
2) The Variable Frequency Vibration Test, as defined by Mil-Std-883 Method 2007.

Both vibration tests are similar in many aspects, although they are intended to uncover different types of vibration-related failures. The vibration fatigue test (Method 2005) requires a testing apparatus that is capable of providing sustained vibration within the specified levels, and fail or pass is determined by external visual inspection and electrical test. In this test, the sample is firmly fastened on the vibration platform with its leads adequately secured. The sample is then subjected to a simple harmonic vibration that has a constant amplitude having a peak acceleration corresponding to the specified test condition. The vibration fatigue test shall be performed for 32+/-8 hours minimum in each of the X-, Y-, and Z- orientations. The variable frequency vibration test (Method 2007) requires the same testing apparatus as the vibration fatigue test and its preparation process is similar to that of vibration fatigue test. If the test preparation process is complete, the sample is then subjected to a simple harmonic vibration that has either a peak-to-peak amplitude of 0.06 inch +/- 10% or a peak acceleration of the specified test condition. The vibration frequency shall then be varied approximately logarithmically between 20 and 2,000 Hz. The entire frequency range of 20-2000 Hz and the return to 20 Hz must be traversed in not less than 4 minutes. This cycle shall be performed 4 times in each of the orientations X, Y, and Z, for a total of 12 times. After either vibration test has been completed, external visual inspection of the case, leads, and seals shall be performed at 10 X to 20 X.

Reference Documents

  • Mil-Std883 Method 2005 “Vibration Fatigue”
  • JESD22-B103B “Vibration, Variable Frequency”
Vibration Test and its controller
Vibration Test and its controller

Printed circuit board assemblies experience various mechanical loading conditions during assembly and use. The repeated flexing (cyclic bending) of board during various assembly and test operations and in actual use can cause electrical failures due to circuit board and trace cracks, solder interconnects cracks, and the component cracks. Although the number of repeated bend cycles is small during assembly, the magnitude of flexure can be very significant. On the other hand, the actual use conditions such as repeated key-presses in mobile phone can result in a large number of repeated bend cycles during the life of the product, albeit at a lower magnitude. Since component manufacturers and suppliers cannot evaluate their package performance on actual final products, a board level test method is needed to evaluate the performance of mounted components due to repeated bending of board and compare their performance with other components. This test provides board specifications (the same board as one for drop tests of mobile assembled parts) and the sample is daisy chained to monitor resistance changes. With 9 components each for four boards surface-mounted, this test will be continued for maximum 200,000 cycles until at least 60% of all units have failed.

Bending 시험

Summary of Cyclic Bend Test

Parameter Recommended Optional
Span for support Anvils (mm) 110 N/A
Span of Load Anvils (mm) 78 N/A
Load Anvil to Components Keep-out (the minimum distance from
load anvil centerline to edge of closest components) (mm)
10 N/A
Minimum Anvil radius (mm) 3 N/A
Load Anvil vertical displacement (mm) 2 Up to 4 mm
Load profile Sinusoidal Triangular
Cyclic Frequency (Hz) 1 Up to 3

Reference Documents

  • JESD22-B113 “Board Level Cyclic Bend Test”

Torsion (torque) test is usually performed to determine torque or torsional stress. The actual product may be bent by equipment or human strength during the assembly process or at the board level. Even though a specific level of reliability is secured by environmental tests at specified temperature and humidity conditions, the device may return frequently under the physical condition. So proper tests should be simulated by predicting conditions for assemble and use of the sample product.

Torque test ongoing
Torque test ongoing

Drop test is performed to determine how a product is affected by a sudden shock when it or its package drops during the transportation or by mistaken handling. This test may degrade the performance of a product or give eternal damages and repeated drop tests may simulate the same failure as introduced by drop in the field. Furthermore, the shock pulse (g) transmitted to a surface-mount product in the package or desired locations of a product can be measured by a three-axis accelerometer so that the influence of a drop on the product may be analyzed. This test can cover free fall height up to 84 inch (213cm) and is conducted by equipment provided with steel, concrete and wood base plate. This test can measure various orientations and angles including flatness, corner, and edge. Tests on the durability and shock pulses of a product are conducted according to ASTM D5276-98. Free fall test can be applied to semiconductor components. AEC Q-100 test can be conducted, which stipulates 6-axis drop test on package (MEMS Cavity Device) at the height of 1.2 meters.

Test Methods

  • Box Level Drop Test: Drop test for packaged products
  • Product Level Drop Test: Drop test for products
  • Package Level Drop Test: Drop test for product components

Reference Documents

  • ASTM D5276-98 “Standard Test Method for Drop Test of Loaded Containers by Free Fall”
  • AEC Q-100 Test Group G “Cavity Package Integrity Tests”

Drop test

Drop test

Drop sensor

Drop sensor
3-axis Accelerometer (Model: 350B50)
High amplitude, shock, triaxial ICP® accelerometer, 0.5 mV/g, 10k g range,
w/built-in 2nd order low-pass filter (-3dB at 20 kHz)

Orientation of drop tests

Corner Orientation
Corner Orientation
Edge Orientation
Edge Orientation
Flatness Orientation
Flatness Orientation

Base Plate Type

최상층 Wood Plate → 중간층 Concrete Plate → 최하층 Steel Plate
Soderability test pertains to the process of evaluating the solderability of degrading terminations, such as lead and terminal. The degradation of lead and terminal decreases the general soldering quality during assembling process, which may cause failure during the actual use.
Aspects of failure in solder
Aspects of failure in solder

Solderability test methods include 1) DIP & LOOK, 2) SMD simulation, 3) Wetting Balance, etc.

Test Method Through-Hole Mount Surface Mount
Leadless J-Lead Gull Wing
Dip & Look Test O O O O
Surface Mount Process Simulation Test X O O O
Wetting Balance Solder Pot Test X O O O
Solderability requirements by semiconductor product families

Dip & Look

The Dip & Look is a traditional method for evaluating solderability of semiconductor components. The lead and terminal are dipped into the solder and the soldering state is inspected. To simulate the storage condition of a product for a long time, a preconditioning process (Dry steam at 93 ℃ or BAKE at 150 ℃ for 16 hours) is performed. Dip the cross section of a sample into flux and then into solder at 245 ℃ for 5 seconds. Observe the appearance of the sample at 10X magnifications to find whether or not the intended parts are coated more than 95% and there is any Dewetting, Nonwetting, and pinhole.

Method for testing dip & lock
Method for testing dip & lock

Surface Mount Process Simulation

Evaluate the solderability of SMD-type semiconductor components by simulating the actual reflow environment. Just like Dip and Look method, perform a preconditioning process, apply solder paste on the base board, and set reflow profile according to the solderability and standards of the product to implement the SMD process. Then separate semiconductor components from the board. Finally judge whether or not it is soldered more than 95% through magnification inspection.

Solder paste 도포/제품 결합 ──Reflow Process ─→확대 검사(전/후)

Wetting Balance

Wetting balance test is to measure the wetting forces of lead and terminal imposed by the molten solder on the test surface as it is dipped into and held in the solder bath as a function of time and plotted. The results are expressed by wetting force/ time graphs and provide the acceptance criteria for uniform reproduction and wetting forces. This test measures the strength of the solder pushing and pulling terminal and shows the results as the above graph. As it is a quantitative measurement, it is very useful to compare the characteristics of materials.

Wetting balance tester & Wetting curve
Wetting balance tester & Wetting curve

Reference Documents

  • JEDEC JEDS22-B102D “Solderability”
  • J-STD-002 “Solderability Tests for Component Leads, Terminations, Lugs, Terminals and Wires”