Segmented Bond Pad Design for Parasitic Capacitance Reduction

Solution Overview

Problem

Parasitic capacitances in semiconductor devices due to bond pads degrade electrical performance, particularly in high-performance devices, and existing methods to reduce capacitance, such as using low-k materials, compromise mechanical stability and are limited in thickness and dielectric constant adjustments.

Innovation Solution

A segmented bond pad design where a portion is electrically active and another portion provides mechanical support, isolated from the wire bond, reducing the active area and thereby minimizing parasitic capacitance without altering the dielectric stack thickness or constant.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If the bond pad area is increased to improve mechanical stability, then mechanical stability is improved, but parasitic capacitance increases degrading electrical performance

Engineering Contradiction:

Improvemechanical stabilityVSAvoidparasitic capacitance

Core Design Contradiction:

StrengthVSObject-generated harmful factors

Solution Approach 1:

The bond pad is divided into two distinct portions: an active portion that is electrically connected to the substrate and an inactive portion that is electrically isolated from the substrate. This segmentation allows the inactive portion to contribute to mechanical stability and wire bond support without adding to the parasitic capacitance, as it is electrically isolated. The active portion maintains the necessary electrical connection while being minimized in area to reduce capacitance.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Different portions of the bond pad structure are assigned different electrical properties: the active portion is conductive and electrically connected to the substrate, while the inactive portion is electrically isolated (effectively insulating). This local differentiation of electrical quality allows the structure to simultaneously provide mechanical support and minimize parasitic capacitance by ensuring only the necessary active area contributes to electrical capacitance.

Inventive Principle:

Principle #3Local quality

2Object-generated harmful factors

If low-k materials are used to reduce parasitic capacitance, then parasitic capacitance is reduced, but mechanical stability is compromised

Engineering Contradiction:

Improveparasitic capacitanceVSAvoidmechanical stability

Core Design Contradiction:

Object-generated harmful factorsVSStrength

Solution Approach 1:

The bond pad is divided into two distinct portions: an active portion that is electrically connected to the substrate and an inactive portion that is electrically isolated from the substrate. This segmentation allows the inactive portion to contribute to mechanical stability and wire bond support without adding to the parasitic capacitance, as it is electrically isolated. The active portion maintains the necessary electrical connection while being minimized in area to reduce capacitance.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Different portions of the bond pad structure are assigned different electrical properties: the active portion is conductive and electrically connected to the substrate, while the inactive portion is electrically isolated (effectively insulating). This local differentiation of electrical quality allows the structure to simultaneously provide mechanical support and minimize parasitic capacitance by ensuring only the necessary active area contributes to electrical capacitance.

Inventive Principle:

Principle #3Local quality

3Object-generated harmful factors

If the dielectric stack thickness is increased to reduce capacitance, then parasitic capacitance is reduced, but manufacturing complexity and process limitations are encountered

Engineering Contradiction:

Improveparasitic capacitanceVSAvoiddielectric stack thickness adjustments

Core Design Contradiction:

Object-generated harmful factorsVSDevice complexity

Solution Approach 1:

The bond pad is divided into two distinct portions: an active portion that is electrically connected to the substrate and an inactive portion that is electrically isolated from the substrate. This segmentation allows the inactive portion to contribute to mechanical stability and wire bond support without adding to the parasitic capacitance, as it is electrically isolated. The active portion maintains the necessary electrical connection while being minimized in area to reduce capacitance.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Different portions of the bond pad structure are assigned different electrical properties: the active portion is conductive and electrically connected to the substrate, while the inactive portion is electrically isolated (effectively insulating). This local differentiation of electrical quality allows the structure to simultaneously provide mechanical support and minimize parasitic capacitance by ensuring only the necessary active area contributes to electrical capacitance.

Inventive Principle:

Principle #3Local quality

Data Source

PatentUS9543260B2Segmented bond pads and methods of fabrication thereof

Publication Date: 2017.01.10 INFINEON TECHNOLOGIES AG

AI summary

In accordance with an embodiment of the present invention, a semiconductor device includes a first bond pad disposed at a first side of a substrate. The first bond pad includes a first plurality of pad segments. At least one pad segment of the first plurality of pad segments is electrically isolated from the remaining pad segments of the first plurality of pad segments.