In this dataset, the term covers photosensitive polyimide and photosensitive polybenzoxazole formulations used to pattern redistribution layers directly, without a separate photoresist and etch step. Claims typically address the material’s behaviour during processing — cure temperature, sidewall profile after exposure and development, adhesion to the underlying copper, and elongation retention after thermal cycling. These properties matter because the dielectric has to survive both lithographic patterning and the mechanical stresses of subsequent packaging steps.

The assignee ranking is led by one company with 724 of the 2,922 records in scope, well ahead of the fifth-place holder at 107 records. The top five assignees combined hold 48.8% of all records, and the top ten hold 60.5%, indicating a field with a concentrated core and a long tail of smaller filers. Recent-year momentum data shows some of these same leaders filing far less in the latest tracked year, though publication lag means the most recent one to two years are still incomplete.

Complete-year data shows filings grew 8% from 279 in 2021 to 300 in 2024, with a peak of 339 in 2022. Numbers for 2025 and 2026 appear lower, but that reflects publication lag — patent applications typically publish around 18 months after filing — rather than an actual drop in filing activity. Any conclusion about a slowdown should wait until those later years are fully published.