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Ship-To-Control Standard

Chemicals and Gases Manufacturers Group Executive Committee January 2008








What is the Standard?

A "Ship to Control" supply position is a growing expectation of material suppliers to the IC manufacturing industry. SEMI has adopted standard guidelines for suppliers to follow in developing control limit calculation procedures that can be used as a basis for lot approval procedures.

Why Standardize?

Producer SQC/SPC practices are typically inconsistent internally

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Different parts/divisions of companies have differing practices Form of requests from differing customer divisions sometimes differ

No two customers have requested the same method!


Requests differ substantially

o o o

Implies product fragmentation (one grade becomes many grades) Higher cost Product availability issues

It is in the Roadmap

Basis for Calculating Limits

The standard provides a methodology for calculating statistically based upper and/or lower limits that targets control of product Type I error at 1%. This error is the risk that future in-control product will fall outside the any of the limits for that product. Statistical methodology has adjustments for:

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Sample size Number of parameters being specified Method detection limit censored data Nonnormally distributed data

Device Manufacturer Motivation

Reduced incoming variation implies better process control and less final product variation/failures Supplier use of SQC/SPC results in gradual improvement Limit need for internal monitoring of incoming material quality

Potential Materials Supplier Benefits

Standardization reduces need for customer specific specifications (e.g., product fragmentation and its impact on the supply chain) Minimizes incoming material variation as much as feasible without "cherry-picking" supplier's process Minimizing incoming material variation will make producer's processes more stable Out of control processes can be very expensive for suppliers (implicit motivator to implement good SQC/SPC practices) Good SQC/SPC practices should result in gradual supplier improvement Rigorous statistical methodology should reduce data handling disagreements

Potential Materials Supplier Concerns

Ship to control is costlier for a supplier to provide (unless that product is already over specified) SEMI ship to control tries to not statistically over specify product (1% supplier risk level)




Real supplier risk levels are likely to exceed 1%; may be more costly to produce than anticipated Raw material batch variation (large, infrequent raw material batches used by supplier may not have their variation be fully reflected in the limits) Real supplier risk levels are likely to exceed 1%; producers and suppliers may experience more supply chain issues

Statistical specifications provide what the supplier's process is capable of consistently producing, not necessarily what a producer's process needs

Where Can I Find the Details?

Ship To Control Standard Description ­ available on-line on the Advocacy section of the SEMI Website in the Chemicals and Gases Manufacturer's Group (CGMG) pages SEMI Ship-to-Control Standard ­ available on the SEMI Website


CGMG Charter

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