A substrate like PCB (SLP) is a high-end PCB that falls between traditional HDI boards and IC packaging boards. It features finer lines, thinner thickness, and higher flatness, making it suitable for chip level packaging such as Fan Out WLP.
Key facts and trends
SLP supports packaging solutions with higher integration, and has been maturely applied in Apple A/M series chips and Nvidia GPUs.
The current mainstream trend is for SLP to evolve towards “approaching true carrier board”, namely HLC (Hybrid Layer Circuit) hybrid lamination technology, further reducing line width/spacing to below 50 μ m.
This field is undergoing a technological transformation from “PCB process improvement” to “semiconductor level manufacturing”, with cleanliness and material purity requirements approaching wafer fab standards.
Controversy and Different Perspectives
There is still controversy over whether SLP should be classified as PCB or semiconductor packaging material. Some experts believe that as its functionality approaches that of IC carrier boards, it may break away from the traditional PCB statistical category and become an independent new industry branch in the future.
✅ Trend evidence: Some manufacturers have invested in building SLP and HLC production lines, with the goal of providing comprehensive PCB solutions for AI applications. (Source: Oriental Wealth Finance Channel, September 6, 2025)