Tag Archives: Microelectronics

Isopropyl Alcohol (IPA): Still the #1 Choice in Cleanrooms

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The most common liquid used for cleaning surfaces in the cleanroom is IPA, primarily because of its purity and consistency. Cleanroom operators sometimes ask if denatured alcohol can replace IPA in the cleanroom.  The simple answer is No.  Here’s why. Denatured alcohol is used for non-critical applications such as fuel for stoves, shellac thinner, and [Read More…]

Cleanroom Paper – Q & A

Question This paper can be autoclaved for Grade A/B cleanroom areas, but can it be used with an inkjet printer and a copier? Will handwritten ink or marker smear or bleed on the paper? Will handwritten ink or marker smear or bleed on the paper when exposed to water or 70% alcohol spray? Answer Our Berkshire [Read More…]

The Truth About “LINT-FREE” Wipes

Lint Free Wipes

“Lint Free Wipes” is a term that evolved with the semiconductor industry since it’s infancy and is a descriptive way of saying the application requires a low-linting solution. A search on the internet returns a plethora of web related searches for Lint Free Wipes. The only problem is that there is technically not such thing [Read More…]

Particles on Surfaces: Part 8 – How Clean is Clean For Microelectronic Companies?

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Let’s focus on one of the most challenging cleaning requirements for the pharmaceutical industry – cleaning equipment used to manufacture injectable materials – so called “parenteral drugs”. These materials must be made in environments that are absolutely clean and sterile, because there is no opportunity for the drugs to be sterilized after packaging – i.e. [Read More…]

Particles on Surfaces: Part 6 – How Clean is Clean?

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The surfaces have been wiped and the obvious question is:  How clean are they? Start with what you see. Do the surfaces look visibly clean?  If not, the wiping activity is not yet done. Wipe to the absence of visible soil on both the surface and the wiper. Keep wiping until the last wiper shows [Read More…]

Particles on Surfaces: Part 5 – Cleaning Floors and Walls

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In a cleanroom, cleaning floors and walls is like cleaning other surfaces, only more so – larger surface areas and corresponding larger wiping cloths. Let’s start with floors. The same principles apply to wiping floors as described previously in Particles on Surfaces Part 4 – use linear wiping strokes and wipe from clean to dirty. To achieve [Read More…]

Particles on Surfaces: Part 4 – Optimum Wiping Techniques

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Before we address wiping techniques, we might well question the need for wiping. After all, if capillary forces hold particles to surfaces strongly enough that the particles can’t easily get airborne, why the great concern to remove the particles by wiping? The simple answer is embodied in two words:  Contact Transfer. That’s the means by which [Read More…]

Particles on Surfaces: Part 2 – The Ties That Bind

In Particles on Surfaces – Part 1, witness wafer and settling plate data showed that particles and bacteria (i.e. viable particles) will settle on cleanroom surfaces. From this we can infer that particles do NOT behave as hard microscopic billiard balls, striking surfaces and rebounding into the air. Rather, through inelastic collisions with the surface, they [Read More…]

Particles on Surfaces: Part 1 – Next to Godliness

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Surely cleanrooms qualify. Air filtered everywhere. Operators garbed from head to foot with only a portion of their faces exposed.  Spotless stainless steel and plastic surfaces everywhere. No paper or cardboard anywhere. Manufactured product protected. Surely this is cleanliness next to Godliness. Appearances are deceiving. Despite the advances made in the High Efficiency Particle Air [Read More…]

“Lint-Free” Wipes: Available Only Through Your Fairy Godmother

Lint Free Wipes

Web searches for “Lint Free Wipes” provide some interesting information.  A Google search returns 82,300 hits. A search of “lint-free” on the American Society for Testing Materials (ASTM) site returns 265 hits, and a search of “lint-free” on the United States Pharmacopeia (USP) site returns 737 hits. Of these, three are contained in the <797> document on [Read More…]