SEMI M38 - Specification for Polished Reclaimed Silicon Wafers
This Standard was technically approved by the Silicon Wafer Global Technical Committee. This edition was approved for publication by the global Audits and Reviews Subcommittee on February 1, 2018. Available at www.semiviews.org and www.semi.org in July 2018; originally published September 1999; previously published March 2012.
Silicon wafers are often subjected to reclaim processes in order to improve manufacturing efficiency in device production. A reclaimed wafer is one that has been re-conditioned for subsequent utilization.
This Specification covers requirements for reclaimed silicon wafers to be used for testing and process monitoring in semiconductor manufacturing.
In some instances for 300 mm wafers with supplier marked back surfaces, it is necessary to re-inscribe the mark after one or more reclaim cycles. Consequently, this Specification also includes an Appendix that covers the re-inscription of such wafers.
This Specification divides reclaimed wafers into four application categories: Mechanical, Furnace, Particle, and Lithography and provides tables of the specification requirements for each category. Thus, a prospective purchaser of reclaimed silicon wafers needs to know which application matches his or her requirements.
Only requirements for some attributes are specified in Tables 1 and 2. Other requirements are indicated to be ‘customer specified’ which means that the customer may specify a requirement for that particular attribute, ‘as-supplied’ which means that the attribute has whatever value was supplied in the wafer delivered (or used) for reclaim, and ‘unspecified’ which means that the attribute is not specified and for which the wafer does not need to be tested.
In addition to the general categories listed in ¶ 2.1, this Specification provides requirements for reclaimed wafers intended for use in advanced device production, including devices in the 180 and 130 nm technology generations in the third table.
This Specification is directed specifically to silicon wafers with one or both polished surfaces. If the wafers have epitaxial deposits, the attributes of the epitaxial layer are not included the specification requirements.
This Specification covers reclaim wafers that are either customer-supplied or third party-sourced. The user should exercise caution when sourcing materials with unknown thermal histories, unknown bulk contamination, or unknown deposits, such as gold (Au) films.
For applications placing higher demands on silicon wafers such as particle counting, measuring pattern resolution in a photolithography process, or surface ion contamination monitoring, the customer may want to reference SEMI M1, SEMI M8, or SEMI M24.
For reference purposes, U.S. customary units shall be used for wafers of 2- and 3-inch nominal diameter and System International (SI), commonly called metric, units for 100 mm and larger diameter wafers.
Referenced SEMI Standards
SEMI M1 — Specification for Polished Single Crystal Silicon Wafers
SEMI M8 — Specification for Polished Monocrystalline Silicon Test Wafers
SEMI M24 — Specification for Polished Monocrystalline Silicon Premium Wafers
SEMI M31 — Specification for Mechanical Features of Front Opening Shipping Box Used to Transport and Ship 300 mm Wafers
SEMI M45 — Specification for 300 mm Wafer Shipping System
SEMI M59 — Terminology for Silicon Technology
SEMI T3 —Specification for Wafer Box Labels
SEMI T7 — Specification for Back Surface Marking of Double-Side Polished Wafers with a Two-Dimensional Matrix Code Symbol