Quality and Integrity
The Wafer Sort Controller (WSC) supports the use of a Barcode Reader and Optical Character Recognition (OCR), both of which enhance the production process by guaranteeing lot and wafer integrity.
The WSC provides the ability to print the lot number in barcode format at the top of each lot summary sheet. This feature ensures lot number integrity for lot tracking purposes where barcode scanners are available.
Another important feature is the ability to define the ‘reference die’ position at an easily recognisable position on the wafer, providing a visual aid during product set-up and ensuring ‘reference die’ integrity.
In addition, a wafer level ‘maverick’ yield trigger can be set such that ‘maverick’ wafers are highlighted on the lot summary once probing is complete, and the user is given the option to remove them via the Summary Editor.
The WSC provides an Automation Mode option that strictly controls the production setup, enabling the product specific automated download of both the prober and tester based on the lot number, which can be entered manually or via a barcode reader.
Automation Mode not only guarantees the integrity of the production setup but also reduces system setup time which can result in throughput gains. Once the system has been setup it is valid for any subsequent lots of the same product.
The Automation Mode is enabled via the System Configuration Menu.
Die Kill Tool
The Wafer Sort Controller (WSC) provides the ability to downgrade die that for some reason need to be rejected after all previous processes have been completed i.e. wafer probe, AVI and MDE.
The Die Kill Tool enables the user to perform this function off-line or manually on the prober itself.
The WSC enables the user to manually step around the wafer to identify the additional failing die, or use the mouse to ‘draw’ around the affected area on the wafer map.
The WSC assigns a Bin 0 to identify this particular type of failure and the wafer/lot summaries are updated accordingly.
In addition, should all wafers in a lot be affected with the same problem, a template file can be generated and applied to every wafer.
The WSC provides the ability to edit the wafer/lot summary once probing is complete to enable changes to be made to the good die totals should inspection fails exist or for any other reason good die need to be inked out and the good die count adjusted.
The Summary Editor also provides the ability to interactively modify the ‘maverick’ wafer yield trigger enabling the user to assess the impact to the shippable wafers, die quantity and lot yield. Any required changes that are submitted, will result in the lot summary being modified accordingly to reflect these.