Introduction

Pin in paste (PiP) is an advanced soldering technique used in printed circuit board (PCB) assembly. PiPprinting deposits solder paste inside through-hole vias and pads prior to component placement. This enables soldering the through-hole pins and PCB in a single reflow pass. PiP provides benefits over traditional wave soldering or selective soldering methods for through-hole components. This article will provide an in-depth overview of PiP technology, processes, advantages, and implementation considerations.

Overview of Pin in Paste Basics

Pin in paste soldering involves:

• Depositing solder paste into through-hole PCB locations
• Mounting components on the solder paste deposits
• Reflowing to solder component pins and PCB in one step

This contrasts with:

• First inserting pins through empty holes
• Then wave or selective soldering the pins

PiP enables efficient all-surface-mount assembly without separate soldering passes.

Why Use Pin in Paste Soldering?

Pin in paste offers several advantages over traditional through-hole soldering:

Lower Cost

Eliminates need for wave soldering or selective soldering equipment. Reduces capital investment.

Higher Reliability

Minimizes thermal shock to components by eliminating second reflow pass. Avoiding multiple passes improves reliability.

Design Flexibility

Enables mixed SMT and through-hole components to be assembled together. Simplifies designs.

Process Simplicity

Only a single solder reflow pass required for all components. Reduces production steps and cycle time.

High Density Capability

Fine pitch PiP printing facilitates dense component placement not achievable with wave soldering.

Improved Quality

Lower defect rates and more consistent joint quality than wave or selective soldering.

Lead-Free Processing

Lead-free solder paste used for PiP is compatible with RoHS regulations.

For these reasons, PiP utilization continues growing for high complexity and low/medium volume assemblies.

PiP Printing Process Overview

Implementing pin in paste soldering involves three main steps:

1. PiP Dispensing

Solder paste is precisely jetted into the through-hole pads and vias prior to component placement.

• High accuracy paste dispensing machines are used
• Minimal paste volume is deposited
• 100% of holes can be printed or only selected locations

2. Component Placement

Components are mounted by pick and place systems onto the solder paste deposits.

• Paste holds components in place tentatively
• Some adhesive may still be required in some cases
• Components do not shift or tilt ideally

3. Reflow

The assembly undergoes reflow soldering to “tent” solder component pins and pads.

• SAC305 or other solder paste used
• Same profile as for SMT components
• May require dual speed profile

This reflows solder to electrically and mechanically connect pins and finalize solder joints.

PiP Processing Considerations

Optimizing PiP print quality and reliability involves attention to:

Paste Deposit Accuracy

Paste must cleanly dispense inside holes without smearing or shifting during placement.

Minimum Paste Volume

Only sufficient solder paste to form the joint should be dispensed to avoid overflow.

Component Pitch Range

Printing can accommodate fine pitch but not ultra-fine component spacing.

Hole Wall Preparation

Oxides inside drill walls may require plasma treatment to enhance wetting.

Solder Mask Expansion

Solder mask overlaps onto pad copper improves capillary flow.

Reflow Profile

Dual speed profiles with extended soak above liquidus often works best.

Careful process engineering is needed to implement PiP effectively.

PiP Design Rules

To enable reliable PiP soldering, PCB designs should follow guidelines:

• Via Pad Diameters – 0.3mm to 1.0mm range preferred
• Annular Rings – 0.25mm to 0.5mm annular rings around drilled holes
• Hole Spacing – No closer than 3x hole diameter side-to-side
• Copper Plating – ≥25μm copper thickness in holes
• Solder Mask Expansion – 0.05mm to 0.15mm onto pad copper
• Pad Shapes – Round holes easier than slotted holes

Adhering to these PiP design rules ensures paste can dispense and solder can wick effectively.

PiP Applications

Components suitable for pin in paste soldering include:

• Through-hole connectors
• Press-fit pins
• Transformers, inductors, and coils
• Switches and relays
• Terminal blocks and screw terminals
• Regulators and heat sinks
• LED displays and indicators

PiP enables mixed SMT/through-hole assemblies combining advanced and legacy components.

Pros and Cons of PiP Technology

Pin in paste offers advantages but isn’t ideal for all situations:

Advantages

• Lower capital equipment costs
• Improved joint quality and reliability
• Design flexibility
• Lead-free processing
• High density assembly

Disadvantages

• Tight process controls required
• Potential tombstoning without adhesive
• Additional paste deposit step
• Fine pitch components challenging
• Hole wall preparation may be needed

Assemblers should weigh the tradeoffs versus production volumes, cost targets, and product complexity when considering adopting PiP.

The Future of Pin in Paste Soldering

PiP utilization continues growing as dispensing accuracy improves and designs shift towards mixed SMT/through-hole assemblies. Continued progress in solder paste formulation, hole wall surface finishes, and advanced profiling will further expand PiP soldering adoption. Its flexibility and technical capabilities position PiP well for meeting future electronics assembly requirements.

Conclusion

Pin in paste soldering delivers an efficient process for assembling through-hole components without wave or selective soldering equipment. By dispensing solder paste into PCB pads and vias prior to placement, reflow can solder pins and through-holes in one pass. With tight process controls and design considerations, PiP enables high performance mixed technology assemblies. As demand grows for flexible, high-mix production, PiP stands poised to become an increasingly valued assembly process option.

Frequently Asked Questions

Q: What types of solder paste are used for pin in paste processes?

Standard “no-clean” SAC305 solder pastes are suitable for many PiP applications. For challenging situations, solder pastes engineered specifically for PiP with wider reflow profiles may be preferred.

Q: Does PiP allow double-sided reflow soldering?

Yes, PiP printing can be done on both sides of a PCB followed by double-sided component placement. Dual reflow would then solder all joints in one pass. This further simplifies processing.

Q: How does PiP soldering compare cost-wise to wave soldering?

Eliminating wave soldering equipment provides significant cost savings on lower to medium volume production. For very high volumes, dedicated wave solder may still be more cost effective than PiP bypassing capital expenses.

Q: What are the limitations on component pin pitch with PiP?

The finest pitch achievable with PiP is around 1mm pin spacing depending on hole size. Ultra-fine pitch components may still require traditional soldering approaches.

Q: Can solder paste be dispensed into plated through holes or is plating needed?

PiP printing can work with both plated and non-plated holes. But plating provides stronger metallurgy for soldering. Preparation may be needed on non-plated holes walls.

Pin in Paste (PiP) Technology in SMT Assembly:

We all know the increasing technological advancement in electronics industry, the core reason for which is the growing competition among PCB manufacturers and suppliers. Every PCB CEM (Contract Electronic Manufacturer) is find new ways to cut cost, increase quality and shorten the lead time of PCBs fabrication, assembly, testing and delivery. So talking about the cutting the cost is a highly significant in increasing profit gains and thus ultimately leading the particular CEM in the race of PCB manufacturing competitors.

There are many ways to reduce the manufacturing cost of PCB fabrication and assembly like PCBs with multiple layers are mostly High Density Interconnect (HDI) PCBs, so they are expensive as compared to single or double layer PCBs, so in order to compare the cost analysis of PCB manufacturing, it is important to consider two PCBs with same parameters like they both should be multilayer, HDI and SMT + THT components based. However the difference making aspect in terms of cost analysis are the 1- Surface Finish methods 2- PCB components selection 3- Component Sourcing 4- Process cost 5- Labor Cost and 6- Overhead expenses can determine the ultimate cost per PCB that is produced by CEM.

In this article we will discuss the most powerful method of component mounting in prototype PCB assembly process that will ultimately reduce the cost of manufacturing and speed up the process thus resulting in less lead time.

Comparison of Commonly Practiced SMT/THT PCBA and PiP:

While the most of the PCB manufactures and assemblers use the reflow soldering method for SMT (Surface Mount Technology) components assembly and then manual soldering or wave soldering of THT (Through Hole Technology) components, the best method to carry out is the PiP (Pin in Paste) method. The following flow chart shows the common process flow of SMT and THT components assembly.

Now in contrast to the above process flow, the PiP (Pin in Paste) PCBA process flow is lot simpler and easier. Checkout the below mentioned PiP process flow chart.

As you can see that the process is shortened tremendously, this is because the SMT and Through-hole components are baked by the same Reflow Oven that was used to bake only SMT parts. The PiP process is simplified in following manner.

• 1- The additional process of manual assembly of THT electronic components is eliminated
• 2- Wave Soldering is not required
• 3- Additional PCB Assembly process setup machine i.e. Wave soldering machine is not required
• 4- Additional labor not required to work on PCB coming out of vacuum reflow oven

Advantages of PiP:

• 1- Elimination of capital equipment like wave soldering machine, laser soldering machines or any other equipment associated with Through hole soldering
• 2- Saving labor cost by eliminating hand soldering and labor associated with wave soldering process
• 3- Cost can be saved by reclaiming floor space used in the wave and hand soldering processes.
• 4- Material cost saving like solder bars, fluxes, wave solder pallets and other hazardous materials in the wave solder process.
• 5- Other indirect incentives lesser number of through-hole connection by replacing THT components to their equivalent SMT and reduction in heating operations. Because various stages of heating cycle like reflow, wave or hand soldering can increase the risk of damage to the board and component, hence eliminating the wave and hand soldering methods in PiP is a big benefit.
• 6- The greatest advantage of PiP is the ability to design PCB with complex components on bottom side, in traditional process most complex components can only be placed on top side of PCB because they are not able to pass through the wave solder process. By eliminating the wave solder process the PCBs can be designed with complex components on both top and bottom side. This makes it easy to design smaller and denser PCBs for smaller electronic devices

So what is actually PiP technology..?

As we know that the Through-Hole components are those that have pins/leads and they need to be inserted into the PCB holes and then soldered manually or by wave soldering machine. A technology that was first used in 1985 by Motorola to solder the THT components in reflow soldering oven and that made strong joints though.

In the pin-and-paste technology, also known as THR (= Through-Hole-Reflow) technology leaded components (THT) are soldered in the reflow process. Paste is printed by means of stencils or dispenser into the through holes for the pins and the through-hole components are assembled on the board. The Pin in Paste PiP is also known as intrusive reflow, Reflow on through hole (ROT), Solder paste on Through Hole technology (SPOTT) and Alternative assembly and reflow technology (AART).

How is PiP Done.?

First of all, the circuit board is printed with solder paste in stencil printer. The stencil printer apply the solder paste on all SMT and THT components locations. Then it may pass through the dispenser for manual dispensing of solder paste, then the SMT and THT components are placed on PCB by means of pick and place robot. After this the whole assembly is placed in vacuum reflow soldering oven, where the solder paste is melted and SMT plus THT components are soldered on PCB. This seems a lot simpler process flow but it can have several challenges which are mentioned below.

Usually the manual hand driven solder paste dispenser is suitable for prototype PCB assembly process where larger production run of PCB is not the case. An example of solder paste dispenser syringe is shown in figure. In the prototyping case, the manual components handling/placement on PCB is recommended.

A solder paste stencil example is shown in the figure below

Challenges of PiP PCBA Technology:

• 1- The through hole THT and SMT surface mount components are needed to be baked in Reflow oven hence they (whole component including terminal and plastic body i.e. casing) must have capability to withstand high temperature like 260^OC for 10 seconds.
• 2- Because some THT components do not have their equivalent SMT versions so those THT components have to be assembled on PCB and cannot be avoided.
• 3- The THT component should be selected such that its housing/casing construction allow a visual inspection of the solder joint.
• 4- A protective stand-off pad beneath the component’s casing/body must be placed to ensure there is no touching/contact with the solder paste during reflow process.
• 5- The high speed automated pick and place robot can grab the THT and SMT component from its planar surface to place it on PCB.
• 6- It can be difficult to provide an adequate solder paste for through hole joints with stencil printing process.

These challenges can be covered by properly focusing on the requirements of Pin in Paste PCB assembly. Some of them are discussed here.

Component Requirement:

• 1- The component SMT or THT selected for PiP must survive the high temperature of reflow oven
• 2- The THT components must be selected in a way that it fits the requirements of SMT pick and place robot machine, to be picked and placed on PCB automatically and accurately. These requirements are the component height, component shape and spacing between component pins.
• 3- The layer of tin must be coated on top of vias for THR (Through Hole Reflow), hence to achieve this, the minimum distance between component and PCB should be between 0.3mm to 0.7mm and the THT component lead should be 1.5mm thicker than the PCB thickness in order to meet IPC3 standard.

Component Pad Requirements:

• 1- It is recommended that the smaller components placed on bottom side and larger components on top side. A minimum of 2mm spacing must be kept around PIP components; if there are multiple PIP components then at-least 10mm spacing between adjacent PiP components must be ensured to avoid interference during automatic mounting by Pick and place robot.
• 2- The distance between adjacent through hole centers should be at least 2mm, distance between edges of adjacent pads should be at least 0.6mm, distance between pad edge and aperture diameter should be at least 0.3mm. Pad aperture diameter should be larger than component pin diameter by 0.2 to 0.4mm. This is done to avoid tin connection between adjacent pins or between pads.

Stencil Requirements:

• 1- The most important parameter for stronger solder joint is the amount/volume of solder paste being printed by stencil, this is governed by diameter of through holes, thickness of substrate and lead shape. The tin paste must fill the electroplated through hole and fillets are on the top and bottom of PCB.
• 2- The amount of tin paste required by THT solder joints is larger than the required by SMT
• 3- Usually the flux fills the 50% of the volume of plated through-hole and remaining 50% is filled by tin paste, hence air bubbles or voids can form when the flux is volatized after soldering process. This can be troublesome, so suitable amount of solder/tin paste must be applied on each through-hole pad.
• 4- The ideal tin paste filling must be greater than 90% and tin paste filling amount in through holes must be greater than bottom pad by 0.5 to 1mm. A squeegee angle of 45^Ois reasonable however the smaller the squeegee angle the more then tin paste is filled in the through hole and greater the angle the lesser the tin paste fill in through hole as show in diagram below where V velocity is constant in both cases.

Reflow Oven Requirements:

• The reflow oven temperature settings allow the smooth and steady heat transmission through radiation to the solder pads of SMT and solder joints of THT. As can be seen from the typical reflow temperature profile, the liquidus is at 217^OC for 45-75 seconds. This is actually the reflow window, however the slow ramp of 1-3^OC is important for stable temperature rise and then degrading the temperature uniformly at the rate of 2-4^OC finishes of the reflow process.

Conclusion:

Summing it up all, we can say that PiP (Pin in Paste) method of PCB assembly is extraordinarily useful for mass production of smaller, denser and lighter PCBAs which can cut the cost of production tremendously. With Pin in Paste technology one can have a stronger and better THT solder joint as that of manual or wave soldering and can place complex SMT components on both sides of PCB thus optimizing PCB board space and miniaturizing electronic devices.

Introduction

Copper clad laminate (CCL) forms the basic structure of printed circuit boards. CCL consists of a central insulating core material sandwiched between layers of copper foil. The manufacturing process to create quality CCL utilizing epoxy resin involves multiple steps including impregnation, lamination, copper bonding, and final finishing. This article will overview the end-to-end CCL production process using epoxy resin chemistry.

Overview of CCL with Epoxy Resin

CCL material consists of:

• Central insulating dielectric core
• Layer of copper foil on each side
• Epoxy resin throughout core

The core provides mechanical support. Epoxy resin gives chemical adhesion and bond integrity. Copper foil enables circuit patterning.

Epoxy resin CCL offers:

• High bond strength
• Good thermal performance
• Excellent chemical resistance
• Long-term reliability
• Cost effective manufacturing

Epoxy resins are the most common resin system used in PCB materials.

CCL Manufacturing Steps

Producing quality CCL with epoxy resin involves the following key steps:

1. Core Material Preparation

The insulating core material comes in sheets consisting of woven fiberglass cloth. The material is inspected, cleaned, batched, and staged for impregnation.

2. Resin Mixing

Liquid epoxy resin is weighed and mixed with hardeners and other reactive additives to form the impregnation resin. The mix is filtered for cleanliness.

3. Impregnation

The core material is pulled through a tank of prepared resin. The woven glass cloth fully wets out as resin penetrates evenly throughout each sheet. This stage determines final resin content.

4. B-Stage Oven Curing

The impregnated core material is pulled through a long heated tunnel oven. Heat causes partial curing of the resin into a tacky B-stage state ready for lamination.

5. Copper Foil Bonding

Rolls of thin copper foil are pressed onto both sides of the impregnated, B-stage core material. The assembly then enters a heated nip roller press.

6. Autoclave Lamination

The copper clad sheet enters an autoclave chamber. High pressure and heat fully cures the resin bonding the foil to the core into a solid laminate.

7. Cooling

After autoclave curing, the laminate passes through a cooling zone to bring CCL temperature back down for additional processing.

8. Roller Treatment

Roller presses apply mechanical pressure to ensure lamination uniformity, remove any air pockets, and improve surface smoothness.

9. Machining

Computer numeric control (CNC) routers machine the CCL into standardized sheet sizes with beveled edges. Holes may also be drilled.

10. Quality Inspection

100% inspection of CCL sheets checks for defects, thickness, hole quality, and other metrics to ensure specifications are met.

11. Packaging

Inspected sheets are carefully packaged to avoid damage prior to shipment or further PCB processing.

The CCL sheets must meet exacting standards to endure PCB fabrication, assembly, and service life. Strict process controls provide consistent, high-quality CCL product.

Key Process Considerations

Several factors are critical during CCL manufacture:

Resin Content

The amount of resin solids impregnated into the woven glass must stay within a target range. Too much or too little resin impacts properties.

No Voids

Air pockets between glass fibers or delaminations create weak points that can cause PCB failures.

Controlled Thickness

Consistent core thickness is critical across each CCL lot. Thickness uniformity impacts subsequent PCB processes.

Bond Integrity

Strong, uniform bonds between resin, foil, and glass withstand PCB processing stresses and temperature cycling.

Dimensional Stability

Sheets must exhibit minimal curling or shrinking to avoid registration issues during PCB imaging and etching.

Cleanliness

No residue or foreign material can remain on surfaces or in the core to prevent PCB defects.

Maintaining strict tolerances and disciplines for these parameters ensures reliable CCL quality.

Material Options

Various material options exist when formulating CCL with epoxy resin:

Epoxy Chemistry

• Standard Bisphenol A epoxy
• High Tg epoxy for improved thermal capability
• Halogen-free epoxy for environmental compliance
• Low Dk epoxies to reduce signal loss

Core Material

• Standard E-glass with greater resin absorption
• Quartz glass that absorbs less resin
• Non-woven aramid or polyester fibers

Copper Foil

• Standard ED copper
• Rolled annealed copper for high ductility
• Low profile copper foils

Coatings – Treatments can be applied to finished CCL sheets:

• Oxide surface treatments to improve resin bonding
• Graphite coatings to reduce drilling debris

The choices result in application-specific CCL material optimized for electrical, thermal, and mechanical needs.

Quality Control Testing

To validate material performance, CCL undergoes extensive quality control testing at multiple stages:

• Interlaminar Bond Testing – Measures resin-to-foil peel strength
• Microsection Analysis – Checks layer uniformity under magnification
• Thermal Stress Testing – Evaluates degradation under temperature cycling
• Fabrication Simulation – Test drilling, imaging, and etching on samples
• Dielectric Analysis – Determines dielectric constant and loss tangent
• Dimensional Stability Analysis – Quantifies shrinkage and expansion
• Electrical Testing – Verifies dielectric breakdown voltage

Statistical process control with extensive testing provides the assurance of product quality and consistency.

Conclusion

Manufacturing reliable copper clad laminate utilizing epoxy resin requires careful process control and validation. When executed properly, CCL provides the robust foundation needed for further PCB fabrication and assembly into quality electronic products. The combination of high performance resins, sturdy core materials, and advanced manufacturing techniques enables CCL to serve its vital role in the production of printed circuit boards.

Frequently Asked Questions

Q: Why is fiberglass most commonly used as the core material in CCL?

Fiberglass provides an optimal balance of mechanical strength, dimensional stability across temperature variations, dielectric performance, and cost-effectiveness. The woven glass cloth construction also absorbs resin effectively during impregnation.

Q: What are some key advantages of epoxy resin systems?

Epoxy resins offer high adhesive strength, chemical and moisture resistance, good dielectric properties, processing versatility, and cost efficiency. These characteristics make epoxies ideal for electrical applications.

Q: What is the difference between FR-4 and other common CCL designations?

FR-4 is a specific flame-retardant grade of CCL made from brominated epoxy resin and E-glass core. Other grades like G-10 and FR-5 indicate different resin systems, core materials, and characteristics optimized for specific applications.

Q: How does CCL thickness tolerance impact PCB manufacturing?

Consistent CCL thickness is critical for maintaining registration during layer-to-layer imaging and etching processes in PCB fabrication. Tighter thickness tolerances enable higher density PCB technologies.

Q: What is the purpose of beveled edges on CCL sheets?

Beveled edges prevent sharp corners from damaging handling equipment or operators. The angled edges also help avoid peeling or lifting during inner layer lamination in multilayer PCB fabrication.

Introduction

Printed circuit boards (PCB) play a pivotal role in the functioning and performance of automotive electronics. From powertrain systems to ADAS, infotainment and lighting, PCBs can be found enabling various functions. The harsh under-the-hood environment along with increasing electronics complexity impose stringent requirements on automotive PCBs. In this article, we will take a look at key PCB applications in vehicles, critical design considerations and specialized PCB types used in the automotive industry.

PCB Applications in Automotive

Some major application areas using PCB technology in modern vehicles:

Powertrain Control

• Engine control unit
• Transmission control module
• Battery management system
• Traction inverter & converter

ADAS Systems

• Camera modules
• Radar PCBs
• LiDAR electronics
• Vision processing units

Infotainment Head-units

• Navigation system
• Audio amplifier
• Telematics gateway
• Display graphics module

Body Control

• Lighting/luminaire PCBs
• Door control module
• HVAC control
• Central gateway ECU

Instrument Clusters

• Odometer
• Driver information display
• Telltales and warning lights

Security Modules

• Immobilizer PCB
• Central locking ECU
• Blind spot detection

PCB Design Challenges in Automotive

Designing PCBs for automotive applications brings unique challenges:

High Vibration/Shock Loads

• Vibration from engine and road noises.
• Shock from bumps and unequal road surfaces.

Wide Temperature Range

• Under-the-hood temperature up to 125°C.
• Cold temperature down to -40°C.

Electromagnetic Interference

• Switching noise from motors and actuators.
• RF interference from transmitters.

High Voltages

• DC bus voltage upto 650V in electric vehicles.
• Fast transients like load dump.

Mixed Signal Circuits

• Combination of sensitive analog and noisy digital circuits.

Safety and Reliability Critical

• Rigorous product validation needed.
• Adherence to ISO26262 functional safety standard.

Key PCB Design Considerations

To meet the demanding automotive environment, certain design practices are followed:

Component Selection

• Automotive grade components rated for extended temperature range.
• Parts qualified based on AEC-Q101 standard testing.

Layout Design

• Minimum clearance and creepage distance as per ISO 6469-3.
• Safety critical layout separation and partitioning.

Power Integrity

• Robust power distribution network design.
• Protection against voltage transients.
• Effective grounding.

Signal Integrity

• Controlled impedance routing for high-speed buses.
• Effective EMI and noise filtering.

Thermal Management

• Suitable dielectric materials like polyimide for higher temperature rating.
• Thermal vias/slots for heat dissipation.

Vibration Resistance

• Component bonding, underfill and encapsulation techniques.
• Board stiffening elements like aluminum baseplate.

Conformal Coating

• Paraxylene, acrylic, polyurethane or epoxy coating.
• Protection against dust, moisture, chemicals.

Safety Standards

• Compliance to ISO 26262 Functional Safety standard.
• Adherence to MISRA coding guidelines.

Reliability Testing

• Industry standard validation as per AEC-Q100, AEC-Q101.
• Accelerated testing – temperature cycling, humidity, HASS etc.

Types of PCBs Used in Automotive

Different types of PCB technologies and constructions are leveraged to meet the demanding automotive application requirements:

Rigid PCBs

• Conventional FR-4 glass epoxy rigid PCBs.
• Higher Tg variants like FR-4 High Temp for thermal reliability.
• Halogen-free and flame retardant materials.
• Metal core boards for thermal management.

Flexible PCBs

• Single, double or multilayer flex circuits.
• Suit applications with space constraints or movement.
• Polyimide material for flexibility at higher temperatures.

Rigid-Flex PCBs

• Combination of rigid and flexible sections.
• Allows three dimensional routing.
• Used to interconnect multiple PCBs.

Metal Backed PCBs

• Insulated metal substrate (IMS) or metal core PCBs.
• Metal baseplate aids heat dissipation and EMI shielding.

High Frequency PCBs

• RF designs with precise impedance control and absorbers.
• Low-loss material substrates like PTFE.
• Synthetic heat sinks for power amplifiers.

New PCB Trends in Automotive

Emerging trends in automotive PCB technologies include:

HDI PCBs

• High density interconnects to integrate more functionality.
• More routing layers, microvias and thinner dielectrics.

High Thermal Conductivity Dielectrics

• Dielectrics with ceramic fillers for improved thermal dissipation.

Low Temperature Co-fired Ceramic (LTCC)

• Multilayer ceramic PCBs for demanding RF and power modules.

Additive Processes

• Additive fabrication to produce high aspect ratio fine features.
• Technologies like aerosol jet printing.

Embedded Passives

• Passives like resistors and capacitors integrated within the PCB.
• Saves space and improves electrical performance.

Panel Level Packaging

• Panel scale manufacturing vs single PCBs.
• Allows integration of PCB, ICs, passives etc.

Quality and Reliability Testing

• Higher reliance on automotive industry standards like AEC-Q100/101, IPC-A-610G Automotive Addendum.
• In-circuit and functional testing.
• Accelerated life testing.

Conclusion

From engine control units to ADAS cameras, PCBs have become indispensable in modern vehicles due to the electronics revolution. Automotive PCB design requires mastering signal integrity, robust power distribution, thermal management and mechanical reliability while meeting stringent industry standards. As automotive electronics complexity grows exponentially, innovations in PCB materials, high density integration, quality/reliability validation and panel scale manufacturing will be critical to realize future mobility visions.

FAQs

1. What are some key factors driving increased electronics content in automobiles?

Demand for connectivity, infotainment, electrification, autonomous features is driving rapid growth in automotive electronics content.

2. What is the typical temperature rating required for under-the-hood automotive PCBs?

Due to high temperature environment, under-the-hood PCBs must withstand temperatures of 105°C to 125°C.

3. How does ISO26262 relate to automotive PCB design?

It provides an automotive functional safety framework with requirements traceability impacting PCB design validation.

4. Which construction provides higher thermal conductivity – IMS or MC PCB?

Insulated metal substrate (IMS) has dielectric directly bonded to metal baseplate giving higher thermal conductivity than metal core PCB.

5. What are some key board level reliability tests done for automotive PCB qualification?

Common reliability tests include temperature cycling, shock/vibration, humidity/bias, HTOL (high temperature operating life) etc.

The industrial sector has seen a tremendous boom in past decade when the demand in automobile exponentially increased due to rapidly growing automation technology. Today the automobile giants like Toyota, Honda, BMW, Ford and Tesla are producing such a high class automobiles and targeting specific consumer class that can buy such a marvelous piece of art of automation engineering. Besides mechanical engineering miracles we all know that brought the revolution in cars and automobile vehicles, the electronics engineering industry has now got involved extensively in automobile industry. Today’s automobile vehicle is a combination of true art of mechanical and electronics engineering. All of the aesthetics that we see in high class sports car like Lamborghini or Ferrari, or we see power control system in heavy loaded trucks like Caterpillar or Komatsu lifters, cranes etc we see that the control system working behind is based on some sort of Electronic Control System (ECS). And this ECS is founded on Special kind of Automotive PCB.

Applications of Automobile PCBs:

Like Caterpillar 797F mining truck has the electronic clutch pressure control, service break sensor, Engine sensor, ARC switch, service break, secondary break control, axle speed sensor circuit, position and steering sensor circuits. There are lots of other examples of general use consumer cars with impressive dashboard,  with LED or LCD display, GPS and radar electronics embedded on dashboard, FM radio, automatic doors and locking systems, electronic relays to control fuel valves/solenoids, timer circuits for engine, Engine Control Unit (ECU) or Engine Control System (ECS) PCB modules, automatic mirror controller, Airbag controller, and front, rear and side LED light control and drive circuits for headlights, back lights and indicator lights respectively, car speed and acceleration sensor and display circuits, Car Battery Management system circuits, wireless key remote door locking system for car safety, air conditioning control etc.

The auto driver system in modern automobile cars is totally PCB based and highly sophisticated electronic circuits are functioning behind the scene. These PCBs are made pre-programmed for sensing the surrounding environment of car to detect obstacle around it in neat vicinity. This is commonly done by IR and Doppler radar system. The auto robot car driving system will take control of car brake, clutch and race and makes decision based on the inputs from surrounding and programming fed in the complicated automotive PCBs.

Although these automobile PCBs are powered by car batteries which is in most cases maintenance free batteries and all the car electronics is operated by this 12VDC battery system. The cabling and wire harness is laid inside the car along with fuses to prevent the electronics from over current or overvoltage surges.

Electric Vehicle:

Nowadays, we see in newspaper, electronic media and people talking about future cars that will run totally on batteries and no fuel or diesel will be required for car now. Yes this is true, scientist and engineers have come-up with a new invention in the battery system that these batteries will charge in the matter of few hours and will give backup to your care for many days. This system is just like our smart-phones that once charged in few hours will give back-up 2-3 days. But there are differences in this novel technology because some electric vehicle will give few days of back and mileage while other can gives battery charging power for weeks. Obviously, the technology of E-Vehicles or Electric Vehicle is not possible without Automotive PCBs. Although our discussion in previous section was just to power up the accessory car electronics and engine control while the fuel was still the diesel and oil, while here in this case the car is totally “electrified” completely eliminating the need of fuel or diesel.

Types of Automotive PCBs:

From our discussion above it is clear that the automotive PCBs should be something that will give the highest performance in terms of power dissipation, efficient heat transfer, long life cycle and robustness. Commonly if we open up the deck or dashboard of our cars we see a complex electronics and wiring inside with relays, fuses and sockets mounted and connecting various modules with each other. These Electronic components are all mounted on Rigid PCBs that are High Density Interconnect (HDI) PCBs, Heavy copper PCBs to allow high amount of current flow from car battery to accessory electronic, ceramic substrate PCBs to bear against harsh, stringent environment of car surrounding like car moving in deserts, forest, mountainous regions or running in hot sunny weather.

The aluminum based Metal Core PCBs (MCPCBs) are commonly seen in automotive electronics that consist of bright LED lights. These bright LED lights draw high current from battery and in turn gives high luminosity white light. Moreover the small motors hidden inside car body to control the cars fins, windows, side mirrors or any part that is moving, draws good enough current from battery. Hence the need of heavy copper PCB is required to provide least resistance path to the flow of current so as to protect/avoid PCB to melt down due to high temperature / heat generated by high currents.

There are flexible PCBs also found in car electronics front dashboard, connecting large LED, LCD display to the processor board, or connecting various electronic modules each other by flexible PCBs. Flexible PCBs are light weight and can be adjusted/flexed inside the small space available in car deck/dashboard. The combination of rigid and flexible PCBs called Rigid-Flex PCBs are also found in Automotive PCBs.

Rayming PCB Services for Automotive PCBs:

At Rayming PCB Our expertise in manufacturing automotive PCBs is vast. We assure high quality and robust PCB manufacturing services. Our PCBs are ISO 9001-2008 and UL certified, so you know they are reliable, durable that will last long. We are the one-stop shop for all your PCB manufacturing and assembly needs. Our proven reputation among our valued clients shows the quality product we deliver. Please send us the design specifications and details about your Automotive PCB at this email sales@raypcb.com

Future of Automotive and PCB Industry Together:

These two gigantic industries can change the shape of the automation industry. As we witness today that cars have been invented totally depending upon electricity and batteries and completely knocking out the need of fuel pumps. Now in future electric charging stations will charge your car like a smart-phone and your will then drive your car more “Energy efficiently” and more environment friendly. Having said that, the electronics PCB manufacturing and assembly industry is the Part and Parcel of automotive industry. It is just the matter of time that world would see these automotive PCBs being used as an integral part of every car’s engine electronics, as car’s accessories electronics and completely replacing mechanical fuel engines with electronic car engines and interface electric motors to drive your car effectively.