Ceramic Liner for Laser Skiving Copper Pad Protection

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Solution Overview

Problem

Conventional laser skiving techniques for creating cavities in organic substrates are time-consuming and prone to damage, especially when dealing with non-homogeneous materials like mold compound with fillers, often resulting in delamination or breakage of copper pads due to excessive heat and narrow process windows.

Innovation Solution

Incorporating a ceramic liner or fin structures around the copper pads to prevent damage during the laser skiving process, allowing for a high-power laser cavity formation without damaging the underlying copper pads, thereby improving throughput and yield.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If conventional laser skiving techniques are used to create cavities in organic substrates, then cavity formation is achieved, but the process is time-consuming and causes damage to copper pads due to excessive heat

Engineering Contradiction:

Improvecavity formation qualityVSAvoidcopper pad integrity

Core Design Contradiction:

Manufacturing precisionVSReliability

Solution Approach 1:

A ceramic liner is introduced as an intermediary layer between the laser skiving process and the copper pad. The ceramic liner absorbs and dissipates the laser-induced heat, preventing direct thermal damage to the copper pad while still allowing the laser to effectively remove the organic substrate material and form the cavity.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The ceramic liner is deposited onto the copper pad before the laser skiving process begins. This preliminary protective action ensures that the copper pad is already shielded when the high-power laser is applied, preventing thermal damage during cavity formation.

Inventive Principle:

Principle #10Preliminary action

2Productivity

If high-power laser is used for cavity formation, then throughput is improved, but the process window becomes narrow and damage to copper pads occurs

Engineering Contradiction:

Improvecavity formation throughputVSAvoidprocess window

Core Design Contradiction:

ProductivityVSAdaptability or versatility

Solution Approach 1:

The ceramic liner serves as a heat buffer that decouples the high-power laser input from the copper pad, enabling the use of higher laser powers (improving throughput) without proportionally increasing the risk of pad damage. This expands the acceptable process parameter range.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The introduction of the ceramic liner changes the thermal parameters of the system, allowing for higher laser power settings and longer processing times without exceeding the damage threshold of the copper pad, thereby expanding the process window.

Inventive Principle:

Principle #35Parameter changes

3Manufacturing precision

If laser skiving is performed on non-homogeneous materials like mold compound with fillers, then cavity formation is achieved, but delamination and breakage of copper pads occur due to excessive heat

Engineering Contradiction:

Improvecavity formation in non-homogeneous materialVSAvoidthermal damage to copper pad

Core Design Contradiction:

Manufacturing precisionVSObject-affected harmful factors

Solution Approach 1:

The ceramic liner acts as a thermal intermediary that protects the copper pad from the heterogeneous thermal environment created by laser skiving through non-homogeneous mold compound. It provides a stable thermal interface regardless of the variations in the overlying material.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The ceramic liner is applied beforehand to cushion the copper pad against the unpredictable thermal stresses that arise when laser skiving through non-homogeneous materials with varying thermal conductivities and absorption characteristics.

Inventive Principle:

Principle #11Beforehand cushioning (Prior cushioning)

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

The use of ceramic liners or fin structures enables reliable and efficient cavity creation in organic dielectric materials, preventing thermal damage to copper pads and expanding the process window, thus enhancing the laser skiving process's reliability and efficiency.

Implementation Method 1

Conventional laser skiving techniques for creating cavities in organic substrates

Methodology Applied

Scientific EffectLaser ablation: Laser Ablation

Implementation Method 2

removing a portion of the dielectric material to form a cavity

Methodology Applied

Scientific EffectAblation: Ablation

Implementation Method 3

Incorporating a ceramic liner or fin structures around the copper pads to prevent damage during the laser skiving process

Methodology Applied

Scientific EffectThermal conduction: Conduction (thermal)

Data Source

PatentUS20230420378A1Packaging architecture with cavities for embedded interconnect bridges

Publication Date: 2023.12.28 INTEL CORP

AI summary

Embodiments of a microelectronic assembly comprise an interposer comprising a dielectric material and a pad of conductive material having at least one of a ceramic liner and fin structures; at least two integrated circuit (IC) dies coupled to the interposer; and a bridge die in the interposer conductively coupled to the at least two IC dies. The bridge die has a first face and an opposing second face, the first face of the bridge die is proximate to the at least two IC dies, and the second face of the bridge die is in contact with the pad.