Lithographic EMIB Cavity Formation for Scaled Bump Pitch

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Current methods for forming cavities in embedded multi-interconnect bridge (EMIB) technology face challenges with dimensional and positional tolerances, leading to issues like laser punch through and copper pad delamination, especially as bump pitch scales down and organic substrate thickness variations become more unpredictable.

Innovation Solution

The use of lithographic processes to form cavities with sacrificial conductive layers, which are then etched away, improves dimensional and positional tolerances, allowing for more precise control and reducing the risk of copper punch through by aligning cavity formation with other conductive features on the same mask.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If laser skiving is used to form cavities in organic substrates, then cavity formation is achieved, but dimensional and positional tolerances deteriorate leading to laser punch through and copper pad delamination

Engineering Contradiction:

Improvecavity dimensional and positional tolerancesVSAvoidrisk of laser punch through and copper pad delamination

Core Design Contradiction:

Manufacturing precisionVSReliability

Solution Approach 1:

The patent introduces lithographically defined sacrificial conductive layers as intermediary structures that mediate between the laser processing step and the final cavity formation. These sacrificial layers serve as precise templates that guide laser skiving while protecting underlying copper pads, thereby improving both dimensional tolerances and reliability during cavity formation

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent applies preliminary action by forming lithographically patterned sacrificial conductive layers before laser skiving. These pre-formed structures define the exact cavity boundaries and protect critical areas in advance, preventing laser punch through and ensuring precise dimensional control during subsequent processing

Inventive Principle:

Principle #10Preliminary action

2Length of moving object

If bump pitch is scaled down to 30 μm or lower, then finer interconnect bridges are achieved, but organic substrate thickness variation becomes more unpredictable exceeding 40 μm

Engineering Contradiction:

Improvebump pitchVSAvoidorganic layer thickness uniformity

Core Design Contradiction:

Length of moving objectVSManufacturing precision

Solution Approach 1:

The patent changes the parameter of cavity formation from direct laser skiving through variable thickness organic material to a two-step process using lithographically defined sacrificial layers. This parameter change decouples the cavity dimensions from the underlying organic substrate thickness variations, enabling precise cavity formation even when organic layer thickness varies by over 40 μm

Inventive Principle:

Principle #35Parameter changes

3Device complexity

If conventional cavity formation methods are used, then process simplicity is maintained, but cavity location tolerances with respect to adjacent structures deteriorate

Engineering Contradiction:

Improvecavity formation processVSAvoidcavity location tolerances

Core Design Contradiction:

Device complexityVSManufacturing precision

Solution Approach 1:

The patent merges cavity formation with the existing lithographic patterning process by using the same lithography tools and sacrificial layer techniques already employed for conducting features. This integration maintains overall process simplicity while dramatically improving cavity location tolerances through perfect alignment with adjacent structures defined on the same mask

Inventive Principle:

Principle #5Merging (Combining)

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 enhances the reliability of EMIBs by achieving tighter tolerances (+/−3 μm) and perfect true position alignment, reducing the likelihood of defects such as laser punch through and copper pad delamination, while maintaining design rule flexibility.

Implementation Method 1

The use of lithographic processes to form cavities with sacrificial conductive layers

Methodology Applied

Scientific EffectLithography: Photography

Implementation Method 2

which are then etched away, improves dimensional and positional tolerances

Methodology Applied

Scientific EffectEtching: Ablation

Data Source

PatentUS11929330B2Lithographic cavity formation to enable EMIB bump pitch scaling

Publication Date: 2024.03.12 INTEL CORP

AI summary

Embodiments include an electronic package with an embedded multi-interconnect bridge (EMIB) and methods of making such packages. Embodiments include a first layer, that is an organic material and a second layer disposed over the first layer. In an embodiment, a cavity is formed through the second layer to expose a first surface of the first layer. A bridge substrate is in the cavity and is supported by the first surface of the first layer. Embodiments include a first die over the second layer that is electrically coupled to a first contact on the bridge substrate, and a second die over the second layer that is electrically coupled to a second contact on the bridge substrate. In an embodiment the first die is electrically coupled to the second die by the bridge substrate.