Two meanings:
In the context of intellectual property, it usually means developing technology in a room (or with a development team) from which all trade secrets and know-how obtained from a competitor under license, or all copyrighted materials, have been excluded, thus ensuring the technology is independently developed and therefore not subject to the license and any restrictions in the license or royalty obligations. In practice, clean room development is notoriously difficult to do, since it involves careful selection of all materials provided to the clean room developers to ensure the absence of any proprietary information, as well as the location of talented individuals who, oddly enough, during their careers lacked the curiosity to consider details of major technology influencing their industry, e.g., Java programmers who never looked at how Sun’s Java Virtual Machine (JVM) works, or semiconductor developers who are strangely devoid of interest in Intel’s X86 instruction set or the ARM architecture (See Click License, Shrink-Wrap License and Tar-Baby License).
One well-known case arose when Advanced Micro Devices, Inc. sought to develop its own processors compatible with the X86 instruction set used by Intel using a clean room, i.e., a room from which all Intel intellectual property had been excluded, trumpeting its achievement with an “Independence Day” promotion. However, in reality, the hygiene of AMD’s clean room was not complete and its developers had used Intel’s IP. As a result, AMD found itself with two legal problems—a lawsuit with and liability to Intel, and an SEC action resulting from the inaccurate representation of the room’s cleanliness, which AMD ultimately settled.
“Clean room” may also be used to refer to a laboratory or manufacturing facility from which contaminants have been excluded, which are usually subject to a classification system, depending on how rigorous the air cleaning controls are. Clean room standards range from the basic class 1,000,000 and class 100,000 clean rooms to class 100 and class 1 at the highest level of cleanliness. To elaborate, at class 100,000 up to 3.5 million particles (of less than ½ mm) are permissible in each one cubic meter of air, while at class 100 only 3,500 would be allowed. The classification system also relates to how often air in the room is sampled for contaminants, at 100,000 twice a week is acceptable, at higher levels sampling is more or less continuous. The level of clean room used is a function of the quality control requirements for the product—semiconductors for example have high-level clean rooms—and products for use in such facilities usually have to be made in similar environments.