---
title: Cleaner Chemistry and Faster Startup with Next Generation Ancillary Photochemical Filters
description: Discover how next‑gen UPE and Microgard filters boost chemical cleanliness and speed startup in semiconductor fabs. Learn how Entegris innovations reduce extractables in PGME/PGMEA, TMAH, and nBA for improved wafer yield and reliability.
---

[Entegris Blog | Ensights](https://blog.entegris.com)

# [Cleaner Chemistry and Faster Startup with Next Generation Ancillary Photochemical Filters](https://blog.entegris.com/cleaner-chemistry-and-faster-startup-with-next-generation-ancillary-photochemical-filters)

 Written by [Entegris](https://blog.entegris.com/author/entegris) | Dec 22, 2025

Cleaner Chemistry and Faster Startup with Next Generation Ancillary Photochemical Filters

In advanced semiconductor fabs, even trace levels of metal or organic contaminants in ancillary photochemicals, like PGME/PGMEA, TMAH, and nBA, can compromise wafer yield, chip performance, and device reliability. Central Delivery Systems (CDS) must deliver ultra-clean chemicals to photolithography tools, but legacy filters may fall short in removing extractables or enabling fast system startup in photolithography.

Addressing These Challenges:

Entegris recently conducted a study of new UPE (ultra-high molecular weight polyethylene) filters tailored for CDS applications. This study evaluates their performance to reduce extractables and improve filter startup efficiency across three key chemistries: PGME/PGMEA (7:3), 2.38% TMAH (aq), and nBA.

How We Solved It:

Four new filter designs were tested using static soak methods and ICP-MS/GC-FID analysis to quantify metal and organic extractables. The filters included:

- Microgard™ UPE D01 and Nylon N01 for PGME/PGMEA
- Microgard AT 2 nm Dry for nBA
- Microgard AT 2 nm Prewet for 2.38% TMAH (aq)

Each filter was benchmarked against its respective point-of-reference (POR) filter, demonstrating significant improvements in metal and organic extractables in these photochemicals.

| **Photochemical** | **New Filters Evaluated** | **POR** | **Metal Extractables Reduction** | **Organic Extractables Reduction** |
| --- | --- | --- | --- | --- |
| PGME/PGMEA | UPE D01 | UPE | 60% | 70% |
| PGME/PGMEA | Nylon N01 | Nylon | 70% | 50% |
| nBA | Microgard AT 2 nm Dry | PTFE A | 50% | 40% |
| 2.38% TMAH (aq) | Microgard AT 2 nm Prewet | PTFE B | 90% | N/A |

 

Conclusion and What’s Next

These next-generation filters significantly improve chemical cleanliness and reduce startup times in automated delivery systems. As fabs scale to sub-3 nm nodes and adopt more complex chemistries, CDS filtration must evolve to meet tighter purity specs.

Watch Lead Author, Patricia Chen describes the study and [download the full Tech Note](https://www.entegris.com/en/home/resources/reference-materials/technical-notes/technote-development-of-ancillary-photochemical-bulk-filters-14232.html).

 

Join us as collaboration partners or bring your individual process needs to solve these challenges. Contact our Experts to get started.

[View full post](https://blog.entegris.com/cleaner-chemistry-and-faster-startup-with-next-generation-ancillary-photochemical-filters)

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