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Chip Scale Review May • June • 2019

[ChipScaleReview.com]

Driving reliability in automotive electronics

assembly materials

By Andy C. Mackie, Andreas Karch, Kay Parker, Erron Pender, Ricky McDonough

[Indium Corporation]

he automotive elect ronics

industry is advancing at a

rate never seen before. The

standard mass-produced passenger car

has evolved over the past 100 years from a

purely mechanical form of transportation

to the “world’s most complex edge

device” (

Figure 1

) [1]. It has been noted

that a 2018 luxury car used over 100

million lines of code to run its operations

[2]. Ensuring potential 24/7 functionality

and long-term reliability has never been

more challenging.

From a technology standpoint, electric-

powered vehicles (EV) are al ready

making signif icant inroads into the

global market as we slowly move away

from the standard internal combustion

engine (ICE). Over the next 15 years,

major cities could see individual car

ownership giving way to mobility as a

service (MaaS), potentially enabled by

autonomous driving (AD) driverless

cars using 5G wireless infrastructure.

Advances toward true AD (so-called

“level 5” cars) are already bearing fruit

as level 2-4 advanced driver-assistance

systems (ADAS), which enable the safer

operation of standard human-operated

vehicles, whether EV or ICE-powered.

Newer EV manufacturers are blurring

the lines between a Tier I (traditional

electronic subassembly supplier) and a

semiconductor supplier, such as in the

area of EV engine control technology [3].

This is a trend we can expect to continue

as the need for increased functionality

i n sma l l e r p a c k a g e s t h a t d r i v e s

heterogeneous integration ineluctably

moves f rom digital into analog and

power packaging, driven by the need for

increased power density.

This technology evolution towards

EV will also impact infrastructure, such

as charging stations and the power grid.

Since the beginning of 2018, European

or ig i nal equ ipment manu fa ct u re r s

(OEMs) have been pushing for mostly

battery electric vehicles (BEV) in the

European market by 2025; however, it

has been estimated that an overnight

conversion of all passenger vehicles in the

USA to electric power would require a

35% increase [4] in the total electric grid

capacity to supply power for charging

those vehicles. An estimated 350-500kW

or more would be needed for the fastest

charging stations; probably at 1,000V,

with the last 10-20% of battery charging

always proving the slowest [5].

Evolution of mission profile

One of the key elements in defining the

reliability of a vehicle, and of its systems

and components, is its “mission profile.”

This is the series of environments—

such as temperature, humidity, vibration,

dust, and salt-spray—and usage scenarios

that a vehicle will be exposed to in a set

period of time. A “100,000-mile/10-year”

warranty is typical for a modern ICE

vehicle. Mission profiles have a central

role in reliability assessment as they take

into account the key factors that affect

systems both in the operating or non-

operating modes.

One recent example for a future EV

usage mission profile was given by Audi [6]:

• Driving (8,000 hours);

• Charging (30,000 hours); and

• Off-grid parking (92,000 hours).

This mission profile results in a total of

15 years of required working life for the car,

and a 50% increase in lifetime warranties.

Reliability by location in vehicle

The mission prof ile describes the

a u t omo t i v e ov e r a l l e n v i r o n me n t

challenges, but each location in the car

will see a different use case. The long-

established Automotive Elect ronics

Cou nci l (AEC) st a nd a rd Q100 for

i nt eg r a t ed c i r cu it s cove r s s eve r a l

grades of device usage, from 0 (higher

temperature exposure) down to grade 3

— equivalent to the mild temperature

exposure of mobile devices. “In-cabin”

electronics may be considered to be

in a fairly benign environment (grade

3 or 2), except where the electronics

are dashboard mounted, and hence,

in an ICE car, exposed to more heat

(grade 2 or 1). “Under the hood” for

an ICE car obviously means being in

a compartment with burning fuel, and

T

Figure 1:

Car as edge device.