Embedding Components, Part 7—Semiconductor Placement and Termination Methodologies

Progress in developing high-density embedded-component substrate capability has accelerated through the cooperation and joint development programs between many government and industry organizations and technical universities. In addition to these joint development programs, several independent laboratories and package assembly service providers have developed a number of proprietary processes for embedding the uncased semiconductor elements.

Developers have found that embedding the semiconductors on an inner layer of the PCB or package substrate directly in line with active and passive components mounted on the outer surface ensures that the conductor interface between related components will be minimized.

There are a number of methods used for interconnecting uncased semiconductor components. Semiconductor elements can be mounted onto the core substrate in the faceup orientation or facedown. When placing the die with the active surface of the die facing up, termination will likely adopt copper-plated microvia methodology. Meanwhile, facedown placement will enable the direct interface to land patterns provided on the designated layer of the circuit structure

As noted in Part 6 of this series, the semiconductor fabrication process initially furnishes the die with aluminum bond pads on its perimeter for the traditional wire-bond interface process.

Faceup Semiconductor Termination

Both gold wire-bond and ribbon-bond processes may be applied for completing the die-to-substrate interface. In preparation for this process, a cavity is provided in the substrate (typical of that described in Part 4) to provide clearance for both the die attach and terminal interface. The faceup attachment method traditionally adopts an adhesive material (liquid epoxy or film) for initially attaching the die to the substrate’s surface. Termination lands are positioned on the upper layer of the cavity in line with the wire-bond termination sites on the die element.

To read this entire column, which appeared in the January issue of Design007 Magazine, click here.

Back

2019

Embedding Components, Part 7—Semiconductor Placement and Termination Methodologies

03-11-2019

Progress in developing high-density embedded-component substrate capability has accelerated through the cooperation and joint development programs between many government and industry organizations and technical universities. In addition to these joint development programs, several independent laboratories and package assembly service providers have developed a number of proprietary processes for embedding the uncased semiconductor elements.

View Story

Embedding Components, Part 6: Preparation for Active Semiconductor Elements

01-10-2019

Designers are well aware that a shorter circuit path between the individual die elements, the greater the signal transmission speed, which significantly reduces inductance. By embedding the semiconductors on an inner layer directly in line with related semiconductor packages mounted on the outer surface, the conductor interface distance between die elements will be minimized.

View Story
Back

2018

Embedding Components, Part 5: Alternative Termination Methodologies and Surface Plating Variations

12-19-2018

Because they are furnished with a very thin profile, resistor and capacitor components with different values can be mounted directly onto land patterns on a subsurface layer of the printed circuit structure. However, handling and placing of these small components requires systems with a high level of positional accuracy. Interconnection can be accomplished using either deposited solder paste and reflow processing or applying a conductive polymer material. Due to the extremely small land pattern geometries required for mounting the miniature passive components, companies commonly rely on precision dispensing these materials.

View Story

Embedding Components, Part 4: Passive Component Selection and Land Pattern Development

11-29-2018

As noted in Part 3 of this series, a broad range of discrete passive component elements are candidates for embedding, but the decision to embed these component elements within the multilayer circuit structure must be made early in the design process. While many of these components are easy candidates for integrating into the substrate, others may not be suitable, or they are difficult to rationalize because they involve more complex process methodology.

View Story

Embedding Components, Part 3: Implementing Discrete Passive Devices

11-15-2018

Most of the passive components used in electronics are discrete surface mount components configured to mount onto land patterns furnished on the surface of a PC board. Designers have several choices for providing passive functions in a system design, such as discrete surface-mounted passives, array passives or passive networks, integrated (Rs and Cs) passive devices, and embedded discrete passive components.

View Story

Designers Notebook: Strategies for High-Density PCBs

01-01-2018

As hand-held and portable electronic products and their circuit boards continue to shrink in size, the designer is faced with solving the physical differences between traditional printed board fabrication and what’s commonly referred to as HDI processing. The primary driver for HDI is the increased complexity of the more advanced semiconductor package technology. These differences can be greater than one order of magnitude in interconnection density.

View Story
Back

2017

Strategies for High-Density PCBs

11-27-2017

As hand-held and portable electronic products and their circuit boards continue to shrink in size, the designer is faced with solving the physical differences between traditional printed board fabrication and what’s commonly referred to as high-density interconnect (HDI) processing.

View Story

Embedding Components, Part 2

07-30-2017

Technology and processes for embedding capacitor and inductor elements rely on several unique methodologies. Regarding providing capacitor functions, IPC-4821 defines two methodologies for forming capacitor elements within the PCB structure: laminate-based (copper-dielectric-copper) or planar process and non-laminate process using deposited dielectric materials.

View Story

Embedding Components, Part 1

06-30-2017

The printed circuit has traditionally served as the platform for mounting and interconnecting active and passive components on the outer surfaces. Companies attempting to improve functionality and minimize space are now considering embedding a broad range of these components within the circuit structure. Both uncased active and passive component elements are candidates for embedding but the decision to embed components within the multilayer circuit structure must be made early in the design process.

View Story
Back

2016

Specifying Lead-Free Compatible Surface Finish and Coating for Solderability and Surface Protection

07-06-2016

A majority of the components furnished for electronic assembly are designed for solder attachment to metalized land patterns specifically designed for each device type. Providing a solder process-compatible surface finish on these land patterns is vital...

View Story

Flexible and Rigid-Flex Circuit Design Principles, Part 6

05-26-2016

The designer is generally under pressure to release the documentation and get the flexible circuit into production. There is, however, a great deal at risk. Setting up for medium-to-high volume manufacturing requires significant physical and monetary resources. To avoid potential heat from management, the designer must insist on prototyping the product and a thorough design review prior to release.

View Story

Flexible and Rigid-Flex Circuit Design Principles, Part 5

04-27-2016

The outline profile of the flexible circuit is seldom uniform. One of the primary advantages of the flexible design is that the outline can be sculpted to fit into very oblique shapes. In this column, Vern Solberg focuses on outline planning, physical reinforcement, and accommodating bends and folds in flexible and rigid-flex circuits.

View Story

Flexible and Rigid-Flex Circuit Design Principles, Part 4

03-30-2016

All of the design rules for the glass reinforced-portion of the board (land pattern geometry for mounting surface mount devices, solder mask and the like) are now well-established. One unique facet of fabricating the rigid-flex product is how the flexible portion of the circuit is incorporated with the rigid portion of the circuit. As a general rule for multilayer PCB design, furnish a balanced structure by building up the circuit layers in pairs (4, 6, 8 and so on).

View Story

Flexible and Rigid-Flex Circuit Design Principles, Part 3

03-02-2016

This column focuses on methods for specifying base materials, and also address copper foil variations and fabrication documentation. It is important to research the various products in order to choose the one that best meets the design requirements.

View Story

Flex and Rigid-Flex Circuit Design Principles, Part 2

02-19-2016

Flexible circuits are commonly developed to replace ordinary printed circuit board assemblies that rely on connectors and hardwire for interconnect.

View Story

Flex and Rigid-Flex Circuit Design Principles, Part 1

01-27-2016

Flexible circuits represent an advanced approach to total electronics packaging, typically occupying a niche that replaces ordinary printed circuit board assemblies and the hard-wire interface needed to join assemblies.

View Story
Back

2005

PCB Designers Notebook: Flexible Circuit Design

01-03-2005

The flexible circuit was originally used as a conductive element for interfacing signals from one electronics assembly to another.

View Story
Copyright © 2019 I-Connect007. All rights reserved.