Structured Bonding Layer in Metal-Ceramic Carrier Substrates

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Solution Overview

Problem

Existing carrier substrates, particularly metal-ceramic substrates, face challenges in reducing production effort and complexity, especially in the etching process required for isolating metal sections, which can affect the width of isolation trenches and the shape of the boundary line between metal layers and insulation elements.

Innovation Solution

A method involving a structured active metal layer with a high active metal content (>15% by weight) is used between metal and insulation layers, allowing for a bonding layer with interruptions, which simplifies the etching process by eliminating the need for 'second etching in certain areas, and utilizes a solder base material without active metals to achieve a strong and thin bonding layer.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If a complete bonding layer is used between metal and ceramic layers, then strong bonding is achieved, but extensive etching process is required to isolate metal sections

Engineering Contradiction:
Improvebond strengthVSAvoidetching process complexity
Core Design Contradiction:
StrengthVSDevice complexity

Solution Approach 1:

The bonding layer is segmented into discrete bonding islands rather than forming a continuous layer. This segmentation is achieved by controlling the deposition or formation of bonding material only in specific regions where metal-to-ceramic bonding is required, leaving other regions without bonding material. The segmented structure provides sufficient bonding strength at critical interfaces while eliminating the need for extensive etching to isolate metal sections, as the non-bonding regions naturally provide isolation.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The bonding layer exhibits local quality variations, being present only in specific regions where bonding is needed and absent in regions where isolation is required. This localized bonding approach allows the structure to have different properties in different locations: strong bonding at metal-ceramic interfaces where required, and natural isolation in regions where bonding material is absent, thereby reducing process complexity.

Inventive Principle:
Principle #3Local quality

2Strength

If traditional bonding processes are used, then metal layers are bonded to ceramic layers, but the boundary line shape and isolation trench width are affected

Engineering Contradiction:
Improvebonding reliabilityVSAvoidboundary line precision
Core Design Contradiction:
StrengthVSManufacturing precision

Solution Approach 1:

The bonding layer structure is predetermined and prepared in advance during the layer formation process, with bonding material deposited or formed only in the exact regions where bonding is required. This preliminary structuring eliminates the need for subsequent etching operations to define isolation regions, thereby preserving the precision of boundary lines and isolation trench widths as originally designed, while ensuring reliable bonding at critical interfaces.

Inventive Principle:
Principle #10Preliminary action

3Strength

If active metal content in bonding layer is increased, then bonding strength is improved, but production effort increases

Engineering Contradiction:
Improvebond strengthVSAvoidproduction efficiency
Core Design Contradiction:
StrengthVSProductivity

Solution Approach 1:

The active metal bonding material is extracted from the entire bonding layer and retained only in the specific regions where bonding is required. By removing the bonding material from non-essential regions, the total quantity of active metal needed is reduced, thereby decreasing material costs and production effort while maintaining sufficient bonding strength at the critical metal-ceramic interfaces where the bonding material is present.

Inventive Principle:
Principle #2Taking out (Extraction)

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

This approach reduces production effort, enhances the quality of the bond between metal and ceramic layers, and allows for thinner solder layers, improving the efficiency and effectiveness of the carrier substrate's electrical connections while minimizing defects.

Implementation Method 1

This active metal, which is, for example, at least one element from the group consisting of Hf, Ti, Zr, Nb, and Ce, creates a bond between the solder and the ceramic through a chemical reaction

Methodology Applied
Scientific EffectChemical reaction: Chemical Bonding

Implementation Method 2

while the bond between the solder and the metal is a metallic brazing alloy

Methodology Applied
Scientific EffectMetallic brazing alloy: Brazing

Data Source

PatentEP4136941B1Carrier substrate and manufacturing process of a carrier substrate
Publication Date: 2024.04.10 ROGERS GERMANY
  • EP4136941B1 patent drawingFigure 1
  • EP4136941B1 patent drawingFigure 2
  • EP4136941B1 patent drawingFigure 3

AI summary

The invention relates to a method for producing a support substrate (1), in particular a metal-ceramic substrate, according to one of the previous claims, having the steps of: - providing at least one metal layer (10) and an insulating element (30), in particular a ceramic element (30), a glass element, a glass-ceramic element, and/or a high temperature-resistant plastic element, said at least one metal layer (10) and insulating element (30) extending along a main extension plane (HSE), - arranging the at least one metal layer (10) and the insulating element (30) one over the other in a stacking direction (S) running perpendicularly to the main extension plane (HSE), wherein an active metal layer (15) is arranged between the at least one metal layer (10) and the insulating element (30), and - binding the at least one metal layer (10) to the insulating element (30) via the active metal layer (15), thereby forming a binding layer (13) between the at least one metal layer (10) and the insulating element (30), a structured binding layer (12) being formed in particular during the binding process.