车规标准AEC-Q200REV-C(4)

A typical manufacturing requirement is the ability of the component to withstand up to 3 reflows at Pb-free conditions (e.g., top-side, bottom-side, rework). The table in this section below reflects the current mechanical limitations of specific types of passive components in meeting this requirement.

Preconditioning is used to simulate the thermal stress devices must endure during attachment to circuit boards in electronic system manufacturing. These stresses become more severe and, thus, more important to simulate when higher Pb-free temperatures are used. These stresses can then influence the functional life of the device, which is why preconditioning is required before environmental life stress tests.

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4.3.3

Passive SMD Device Preconditioning

Refer to Table 4.2 to determine the maximum number of reflows before the appropriate reliability stress test for a given type of passive component. The difference in the number of reflows represents the differences in capability among the various types of passive devices. The peak reflow temperature for Pb-free forward compatibility, measured as the reflow oven ambient, is

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260(+0/-5)C when attaching surface mount passive devices onto test boards. If the supplier

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feels their component cannot endure a 260C reflow and demonstrate acceptable life, perform a lower reflow precondition temperature, informing the user immediately of this deviation. Table 4.2 – Preconditioning Reflow Requirements Before Reliability Stress Testing

Qualification Requirements AEC-Q200 SMD Moisture Preconditioning Number of reflow passes required onto test boards is shown per test and type of component. Number is dependent

on technology limitations.

Required Reliability Stress Tests after Preconditioning

Type of Component

Term Str

Ceramic/Tantalum 3 3333Inductor PTC Polymer Thermistor PTC Ceramic Thermistor 2 2 2 2 2

NTC Thermistor Trimmer Varistor Resonator/Crystal Attenuator Bd Flex

HTE

MR

BH

OL

TC

TS

moisture soaking to MSL 1 before reflow for plastic packaged SMD capacitors, inductors and attenuators only. If device is incapable of MSL1, can soak at MSL3 before reflow, but parts must be drypacked for shipment to user.

three reflow passes at 260ºC/20 seconds (instead of 10 seconds) onto test boards

Aluminum electrolytics must be allowed to cool after the first and before the second reflow passes

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4.3.3

Resistance to Dissolution of Metallization Test

Perform this test per section 4.2.4 of J-STD-002 using a solder dip temperature of 260 +0/-5 C.

Table 4.2

Qualification Requirements AEC-Q200 Resistance to Dissolution of J-STD-002

Metallization Section 4.2.4

260+0/-5C

4.3.4

Tin (Sn) Whisker Growth Evaluation

Tin whisker growth is more likely to occur, influenced by complex material and processing conditions, when tin termination plating is used. This is a wearout reliability issue in that these whiskers can grow to contact adjacent terminations to cause false data pulses, intermittent failures and, in extreme circumstances, electrical overstress.

4.3.4.1 Termination Plating If using tin without an underlayer (e.g., Ni) as the termination plating, it must be deposited in a

very clean environment and must display a matte finish. In addition, some studies have shown

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that a tin plating thickness >7um, a nickel underlayer and/or a postbake at 150C/1 hour will minimize the likelihood of whisker growth. These conditions have been identified as major factors in minimizing tin whisker growth.

4.3.4.2 Tin Whisker Growth Testing Suppliers must test for susceptibility to whisker growth during device aging. After each stress,

the terminations shall be observed visually using a high power (>50X) microscope. Any termination displaying a whisker filament greater than or equal to 50um in total axial length shall constitute a failure.

Table 4.3 – Tin Whisker Test Conditions

Stress Type Reference Test Conditions Inspection Minimum

Specification Intervals Duration

Temperature Cycling JESD22 TMIN = -55 (+0/-10)C cycles

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Method A104 TMAX = 85 (+10/-0)C

Air-to-air

tSOAK = 5 to 10 min. ~3 cycles/hour

Ambient Temperature/ 1000 hours 3000 hours 30 +/- 2 C Humidity Storage 60 +/- 3 %RH

High Temperature/ 1000 hours 3000 hours 60 +/- 5 C Humidity Storage 87 +3/-2 %RH

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The above inspection intervals and minimum durations are based on experimental data and are given to make data comparisons easier. Total test durations (cycles/hour) are not specified in JESD22 Method A121. Some experimental data suggests that there is an incubation time during which whiskers do not appear. This incubation time depends on lead finish, thickness of the finish and substrate characteristics. If test durations are too short, whiskers will not be observed. For qualification of lead finishes, test duration and inspection intervals will be defined in the qualification plan agreed to by the supplier and user.

4.4

Data Submission Format

Data summary shall be submitted as defined in Appendix 4. The individual user shall submit raw data and histograms upon request. All data and documents (e.g., justification for non-performed test, etc.) shall be maintained by the supplier in accordance with QS-9000 / TS-16949 requirements.

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TABLE 1 - QUALIFICATION SAMPLE SIZE REQUIREMENTS

Stress NO. Note Sample Size Per Number Accept on

Lot of lots Number

failed

Pre-and Post-Stress 1 G All qualification parts submitted 0 Electrical Test f …… 此处隐藏：5354字，全部文档内容请下载后查看。喜欢就下载吧 ……