Implementing Embedded Component from Concept-to-

ManufacturingIPC APEX 2014

Humair Mandavia,Executive Director, Zuken SOZO

Center

AgendaZUKEN

Embedded Components

Overview of embedded component technologies

Common issues with embedded components

Design for embedded components from concept-to-manufacturing

Summary

Evolution of Computer Engineering

Past innovationsThe origin The Present

Technology continues to evolve

Picture:Wuerth Elektronik

Evolution of PCB design and manufacturing

IPC technology projection 2010

Introduction to embedded PCB components• Embedded PCB Components are components (R’s, C’s,

L’s, IC’s, etc.) that are either formed or placed between inner layers of a PCB.

• Integration of Embedded PCB Components into the PCB, also referred to as 3D PCB integration or technologies, further opens the door to the miniaturization of electronics.

• Some of these technologies have been in use for over 20 years. However, ongoing advances in manufacturing capabilities continue to make it easier to implement in practice.

Trend of Placed Embedded Components for High Frequency Applications [4]

General technological progression to Embedded Components [9]

Advantages and disadvantagesAdvantages:

1. Reduction in outer layer surface area2. Increase in functionality for same surface area (greater density)

• For example, the number of components in mobile phones is increasing, however the general form factor limitations remain the same

3. Performance improvement • Shorter trace lengths with reduced trace inductance - allows for increased circuit

speed

4. Potential decrease in total assembled costs• PCB cost will be higher, but some cost can be offset by fewer total components for

final assembly

5. High pin-count active devices can be embedded directly within the substrate• Protect IP

Advantages and disadvantagesDisadvantages:

1. Too many workarounds to implement within legacy 2D design tools

2. Meeting tolerance requirements can be more difficult for formed components

• Trimming can be slow and expensive

3. Achieving required value from formed (passive) components is difficult

4. Prototype cost is higher5. Embedded components can be damaged during assembly

• Rework is not possible

6. Multiple dies will increase number of power-rails7. Impact on thermal behavior8. Availability of bare-dies from IC vendor? (added cost)

Common issues with embedded components

High-speed packaging issues

Consideration for manufacturing

Implementing embedded components

Design rules for embedded components

High-speed packaging issuesExamples of integrated circuit packages over the last decades

Variations in:• Overall package size

- number of pins- maximum die size

• Pins geometry- pin spacing (pitch)- perimeter vs. area array

• Plastic vs. ceramic package material- hermeticity- thermal properties- cost

High-speed packaging issues

Picture: Renesas [12]

High-speed packaging issuesPackage-less options

• Package-less involves dealing with bare die- Used in multi-chip modules (MCMs), chip-on-board (COB), and other processes

• Motivation:- Reduced cost- Reduced size / volume- Integrated circuit technology trends

o Various die sizeso Growing # of I/Oo Increased power dissipation

Chip on board

PoP module

Placing active components As more functions are required for the same surface

area, there is a rapid increase in the use of embedded placed components.

Some component suppliers are producing specialized low-profile components more suited for embedding into a PCB.

On the upper right there is a stacked SiP with 4 IC-dies embedded shown.

In the example right, embedded cores created by stacking multiple prepreg layers with cavities cut out for the components. Prepreg layers are stacked until all components are covered.

Pressure and heat are then applied to cure the prepreg layers surrounding the components to create a new core. The core with embedded components can then be used as building blocks for the rest of the PCB. Embedded Component Cores

PCB with two embedded cores [3]

(Picture: FhG-IZM Berlin)

Placing active components Two methods of making connects to embedded components are shown below:

1. Solder connection:- This method requires the embedded component to be soldered to an inner layer.- Risk: solder could melt during subsequent processes.

2. Direct via connection:- For this method the component is not soldered to an inner layer trace but rather connected directly to a via.- Benefit: further reduction in trace length.- Risk: the embedded component could be damaged during blind via laser drilling or during via plating.

From the limitations provided above, it should be clear that manufacturability is a key limiting factor in the use of embedded placed components. Ongoing improvements in manufacturability are being pursued to address these concerns.

Embedded PCB Connections for a Placed Capacitor [7]

Dedicated design rules

Picture: Würth

Implementing embedded componentsEasy technology configuration of allowed layers for embedded components is needed, including connection strategy.

ECAD Library Issues for Embedded Components

Embedded discrete on layer 2 Embedded discrete

on layer 3

• Creating footprints/geometries within ECAD library for embedded components

• Simplified definition for embedded component footprints:- Any layer, - Support any number of layers

• Legacy systems require multiple footprints for different layers have been needed for an embedded component

Upfront planning for component placement• Start placement studies during the

product planning phase– Early floorplanning reduces effort in the

detail design process– Understand impact of form, fit, and

function in 2D and 3D– Identify potential obstacles in advance

• Define component rules and constraints during logical circuit design– Correct footprint specification– Specific instructions on placement and

routing

Defining layer placementIssues in PCB design are three dimensional – 3D systems are now required to handle these complexities

Consideration for cavities• Cavities for embedded components are also a 3D problem• Should cavities be pre-defined in the library or interactively

designed during layout?– Dependent on design process

• Design rules/online DRC should consider impact of both embedded– Cavity size– Cavity capacity– Spacing between cavities

Caution with cavities!• Remember that laser cavities will reduce the

routing space – No space to drill vias

Connection of embedded components• Various connection strategies for embedded

components• Creating manufacturing outputs

- Manual output of microvia locations- If modeled in 3D, laser drill point locations can

be exported automatically• TSVs also should be considered for PoP

Embedded comp with double side connections

IVH

PAD Cavity

Design rules for cavities• Work with your manufacturers to understand the requirements

and process!– Implement the rules upfront in your design tools

Picture: Würth

Upfront manufacturing checks and result collaboration

• Design to vendor- and technology-specific manufacturing checks for fabrication and assembly

• Checks should be conducted during and after board layout– Critical step before design is signed-off for

release-to-manufacturing• Communication with manufacturers and

other suppliers/partners– Native design data– Standard file formats: IPC-2581, ODB++– Output of check results to a spreadsheet

with graphical snapshots and check status/feedback

Summary/Conclusion• It is important to understand the challenges involved with

embedded components– Value can be realized – important to plan and drive design to

correct specification• Work closely with your manufactures and capture guidelines

– All major ones are able to implement various embedded component technologies

– Manufacturing process has matured in various industries: consumer, telecom, defense, and medical

• Start placement studies as early as the product planning phase to optimize floorplanning and understand potential design challenges

• Working with these technologies induces a 3D problem– Consider a true 3D design approach for implementation

• Important to design in real-time to correct design and manufacturing rules

References(1) “Printed Circuits Handbook: Sixth Edition, Chapter 21: Embedded Components. “, Clyde F. Coombs, Jr. (2008). New York,

NY: McGraw-Hill(2) “Novel Substrate with Combined Embedded Capacitance and Resistance for Better Electrical Performance and Higher

Integration”, John Andresakis, Daniel Brandler, & Dong Nong, 2006 Electronic Components and Technology Conference.(3) “Optimization of PCB build-up layer configuration for electronic assemblies with active embedded components in the

board”, W.C. Maia Filho, M. Brizoux, & A. Grivon, 11th International Conference on Thermal, Mechanical and Multiphysics Simulation and Experiments in Micro-Electronics and Micro-Systems, EuroSimE 2010.

(4) “Embedded Passive Components to Increase the Reliability of High-Frequency Electronic Circuits”; Yves Ousten, Bruno Levrier, Genevieve Duchamp, & Philippe Kertesz, IXL Enseirb UMR5818, France.

(5) “Embedding components into PCBs needs accurate, reliable placement”. Eric Klaver (2011), www.globalsmteasia.com.(6) “Implementing HDI and Embedded Passives in a High-Reliability Aerospace Application”, Happy Holden, Microsystems,

Packaging, Assembly & Circuits Technology Conference, IMPACT 2008. 3rd International.(7) “PCBs with embedded components emerge for capacitors”, Akihisa Seki, AEI by Dempa Publications, Inc., March 2011.(8) “Design for Embedded Components in PCB Structures”. Dean Wiltshire, www.wirelessdesignmag.com.(9) “Embedded Components in PCB”. Risto Tuominen, Embera Electronics.(10) “Embedded Magnetics Opens Door to New Approach to Circuit Design”, Steven R. Kubes ECN, 55(12), 26-28, November

2011.(11) “Embedded Chip Packages – Technology and Application”, L.Boettcher, D.Manessis, A.Ostmann, S.Karaszkiewicz,

H.Reichl, Frauenhofer-IZM Berlin, SMTA Int. Conference 2008.(12) Renesas: http://www.renesas.eu/products/package/characteristic/index.jsp