Dummy Metallic Trace Layout for Flat Ceramic Substrates

Solution Overview

Problem

Ceramic substrates often exhibit non-planar surfaces due to variations in metallic trace density, leading to stress issues when attaching dies, which can cause damage and reliability problems in electronic devices.

Innovation Solution

Incorporating dummy metallic traces with a density of at least 50% of the functional metallic traces to create a uniform density distribution across the surface, reducing gaps and surface variations, and ensuring these traces are electrically isolated from functional traces to avoid electrical interference.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If functional metallic traces are placed only where needed for electrical connections, then electrical functionality is achieved, but surface non-planarity occurs due to density variations

Engineering Contradiction:

Improveelectrical functionalityVSAvoidsurface planarity

Core Design Contradiction:

ReliabilityVSShape

Solution Approach 1:

The patent applies local quality by creating different regions with different trace densities: functional regions with higher density for electrical connectivity and dummy regions with lower density for surface planarity. The dummy metallic traces are strategically placed in non-functional areas to balance the overall density distribution without interfering with electrical functions.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The patent uses copying by creating dummy metallic traces that replicate the appearance and physical properties of functional traces but without electrical connectivity. These copied traces serve purely to balance density and improve surface planarity, allowing the substrate to maintain uniform thermal and mechanical properties across the entire surface.

Inventive Principle:

Principle #26Copying

2Shape

If dummy metallic traces are added to balance density, then surface flatness improves, but device complexity increases

Engineering Contradiction:

Improvesurface flatnessVSAvoidtrace pattern complexity

Core Design Contradiction:

ShapeVSDevice complexity

Solution Approach 1:

The patent extracts the electrical functionality from the dummy metallic traces, separating it from the density-balancing function. By making the dummy traces electrically isolated through breaks, gaps, or insulation, the design removes unnecessary complexity while retaining the surface flatness benefit. Only the essential density-balancing function remains in the dummy traces.

Inventive Principle:

Principle #2Taking out (Extraction)

3Shape

If metallic trace density is increased uniformly across the surface, then surface planarity improves, but material usage and cost increase

Engineering Contradiction:

Improvesurface planarityVSAvoidmetallic trace material

Core Design Contradiction:

ShapeVSQuantity of substance

Solution Approach 1:

The patent applies local quality by creating different regions with different trace densities: functional regions with higher density for electrical connectivity and dummy regions with lower density for surface planarity. The dummy metallic traces are strategically placed in non-functional areas to balance the overall density distribution without interfering with electrical functions.

Inventive Principle:

Principle #3Local quality

Data Source

PatentUS11990399B2Device with dummy metallic traces

Publication Date: 2024.05.21 TEXAS INSTRUMENTS INC

AI summary

An electronic device includes a substrate having a surface, functional metallic traces on a first portion of the surface that are electrically connected to carry current in the electronic device and have a first density, and dummy metallic traces on a second portion of the surface that are electrically isolated from the functional metallic traces and have a second density that is within at least 50% of the first density.