KGD - The concept

KGD or 'Know Good Die' exists as both a predefined type of product and also as a flexible standard that a product can achieve when it meets specific quality and reliability criteria.

KGD - The product

Die manufacturers offer KGD straight off their production line as an immediately marketable product. KGD product developed by the original manufacturer usually provides assurance that:

1. The die yield will meet the customers requirement within a competitive price budget

2. The die performance will meet the electrical KGD specification it is sold to

3. The die electrical performance will meet or exceed comparable packaged goods in terms of quality and reliability levels.

Manufactured KGD are commonly produced by well established foundries with a long process yield track record which is often described as a 'proven characterisation'. However, there is no universal process flow which 'makes' KGD and the necessary test criteria will always be dependant on variables such as product family type, likely end application or existing yield history data. Often manufacturers will offer various grades of KGD to help guide the customer in choosing the right level of reliability they need in relation to their end application. The golden rule of buying direct KGD product is that the manufacturer gives a 100% guarantee that each die sold has been tested to meet the specification it is marketed at.

KGD - The standard

There is no default standard in place that a part must meet to achieve KGD status and debate still continues today on what should denote an acceptable KGD status.

A KGD status can only truly be given to a product by an engineer possessing the following attributes:

1.Long term experience and knowledge of testing methods used to prove reliability 2.Knowledge of the track history and design maturity of the product in terms of probable yield and reliability 3.Knowledge of the application the product is being designed into, how the product will be assembled into the application and the likely conditions the product will be subject to 4.Knowledge of other components designed into the application related to the product during operation and their characterisation 5.The ability to weigh up the possible tolerance for re-work on the application, should product fail, against the additional cost incurred by applying higher criteria to reach an acceptable KGD standard.

KGD status can only be granted when an engineer with the right qualifications is able to determine the necessary performance specification needed in relation to its application and can prove it with test data and yield results.

Although achieving KGD status is a product specific task, there are usually common routes taken with regards to establishing possible reliability through product testing. Just as an original manufacturer may market KGD product at different levels of performance often a die processor is also able to offer similar degrees of possible reliability dependant on the level of testing the product receives. Once again this helps guide the customer towards establishing the level of reliability their product will need in relation to a set cost. For example Die Technology Ltd offers several core process flows useful for determining KGD status and also develops custom test schedules to meet both new and specialist products which are often lacking in track history or relevant characterisation.

KGD - Capabilities

KGD supplied product Die Technology can supply KGD product from our franchised manufacturers and also advise on the right grading of KGD most suited for the customer application.

KGD tested product Die Technology Ltd offer three core process flows, each of greater complexity and order of cost.

• Process 1 - Manufacturers probed parts are visually screened, a sample taken which is then subjected to element evaluation without burn-in.
• Process 2 - As Process #1 but with 168 hour burn-in and subsequent re-test to manufacturers DC specification.
• Process 3 - As Process #2 but with a hot probe carried out for the DC characteristics prior to the selection of the sample die for the qualification process.

Customer testing schedules can be designed to meet a customers die reliability requirement. Consultancy can also be given regarding KGD and also test analysis where required.

Die Technology are members of the Good-Die project, A European Initiative to Promote Known-Good-Die (KGD) Technologies we are also related to the DPC (Die Products Consortium) whose members include National Semiconductor, Texas Instruments and many other well know die manufacturers.