Introducing LPKF Tensor Ablation: Precision RDL Ablation Without Yield Loss

Economic RDL Opening for Damage-Free Glass Substrate Singulation

LPKF's breakthrough laser technology delivers selective RDL ablation with zero substrate damage, precisely ablating redistribution layers while preserving the structural integrity of the glass core beneath.

What is Tensor Ablation?

Before glass core substrates can be singulated, the RDL and dielectric layers must be selectively removed to expose clean separation paths. This step is critical to ensure precise dicing without damaging the glass. Tensor Ablation performs this with ultra-short pulse laser precision, selectively removing RDL/dielectrics while preserving the underlying glass enabling clean, damage-free singulation.

The SeWaRe Challenge: Why Conventional RDL Removal Fails

Glass core substrate singulation in advanced packaging requires first removing the redistribution layers (RDL) and build‑up dielectrics such as ABF at the panel edges, so the glass core can be cleanly separated into individual substrates without shorts or cracks.

However, manufacturers working with glass core substrates face a persistent problem: conventional ablation methods introduce microdamage and thermal stress that trigger the SeWaRe effect, a defect mechanism where the glass substrate splits internally along a plane, destroying structural integrity and causing catastrophic yield loss.

LPKF Tensor Ablation solves this.

The new laser technology enables selective RDL removal that prevents the SeWaRe effect precisely ablating redistribution layers while preserving complete glass substrate integrity. Where traditional methods create the microcracks, edge damage, and thermal stress that cause substrate splitting, Tensor Ablation delivers clean, damage-free removal.

What makes Tensor Ablation different

For manufacturers building the next generation of glass core packages, fan-out RDL structures, and high-density interposers, Tensor Ablation eliminates the SeWaRe risk, delivering the yield, reliability, and process control that advanced packaging demands.

No substrate microdamage

Eliminates SeWaRe failure initiation

Minimal thermal stress

Prevents CTE mismatch damage

Clean, defect free edges

No edge damage or splitting

Glass integrity preserved

Structural stability through all processing stages

Traditional Ablation vs. LPKF Tensor Ablation

Challenge	Traditional Methods	LPKF Tensor Ablation
SeWaRe Effect Risk	High—thermal and mechanical stress cause microcracks that propagate into substrate splitting	Eliminated — controlled ablation prevents crack initiation and substrate damage
Glass Substrate Integrity	Compromised—visible damage, subsurface defects, and microfractures	Fully preserved — no damage to glass core, no subsurface defects
Edge Quality	Rough, irregular edges with thermal damage and debris	Clean, precise edges — micron-level accuracy with minimal heat-affected zone
Thermal Stress	Significant heat input creates CTE mismatch stress that triggers SeWaRe failures	Minimized — precise energy control reduces thermal load and internal stress
Process Reliability	Inconsistent results, high defect rates, substrate-related failures in downstream processing	Reproducible — consistent quality across substrates and production volumes
Yield Impact	Substrate damage leads to scrapped units and rework	Maximized — eliminates substrate-related yield loss
Downstream Processing Risk	Damaged substrates fail during thermal cycles, assembly, or under mechanical stress	Robust — substrates withstand subsequent processing without SeWaRe splitting

Technical Specifications

Laser System

Laser Type: Ultra-short pulse laser (picosecond/femtosecond regime)

Wavelength: Optimized for selective RDL ablation with minimal glass interaction

Pulse Duration: Picosecond range (minimizes thermal diffusion and substrate damage)

Repetition Rate: High-frequency kHz range (high-throughput processing)

Quality & Control

Process Monitoring: Real-time ablation depth control and quality verification

Defect Detection: Inline inspection for complete RDL removal without substrate damage

Repeatability: Minimal process variation across production runs

SeWaRe Prevention: Zero substrate microdamage confirmed by cross-sectional analysis

Process Capabilities

Material Selectivity: High selectivity between RDL materials (Cu, polymer dielectrics) and glass substrate

Ablation Precision: Sub-micron positioning accuracy

Edge Quality: Clean edges with minimal heat-affected zone

Layer Removal Thickness: Configurable per pass (single or multi-layer removal)

Substrate Compatibility: Borosilicate glass, fused silica, ultra-thin glass (wide thickness range)

Production Performance

Throughput: High throughput capability (depending on panel size and ablation area)

Automation Level: Fully automated substrate handling and processing

Uptime: Designed for 24/7 production environments

Footprint: Compact cleanroom footprint

Applications

Copper RDL Integration: Glass core substrates with copper RDL

Packaging Solutions: Panel-level fan-out packaging

Heterogeneous Integration: Glass interposers for heterogeneous integration

Fine-Pitch Interconnects: High-density interconnect substrates

Innovation & Development: R&D and prototyping for advanced packaging architectures

Why Tensor Ablation Matters

In advanced packaging, the SeWaRe effect isn't just a defect, it's a yield killer that can remain hidden until thermal cycling or mechanical stress causes catastrophic substrate failure.

LPKF Tensor Ablation is purpose-built to eliminate this risk. By combining material-selective laser parameters with precision process control, we deliver RDL removal that protects what matters most: the structural integrity of your glass substrate.

The result? Higher yields, lower rework, and the confidence that your substrates will survive downstream processing and field conditions.