Production of radio frequency ID tags

A method for producing and testing a multiplicity of integrated circuits, comprising:

• forming a multiplicity of integrated circuit dice on a wafer,
• forming a test die on the wafer and connecting the test die to all integrated circuit dice,
• testing all integrated circuit dice by connecting a tester to the test die while all dice remain together on the wafer, and addressing each integrated circuit die via the test die by issuing commands to each die under test and receiving responses for each die relative to parameters of the integrated circuit to be tested,
• gathering test result information for the integrated circuit dice in the test die and the tester and using that information, discarding bad integrated circuit dice on trimming the integrated circuit dice from the wafer, and
• wherein the test die enables all integrated circuit dice for testing simultaneously and sends testing commands to all integrated circuit dice simultaneously, each integrated circuit die having a memory element and each die performing the desired tests and then storing the test results in the memory or register element, and including the test die's then sequentially shifting an enable bit through each tested integrated circuit die sequentially to read status of that die, then the test die's writing a memory element on the die under test to signify that each particular die was tested and whether the die passed or failed, for subsequent determination or to whether the die is to be used.

In the production of an RF ID tag that receives and stores energy from an interrogator signal and sends a responsive signal on a transmit frequency back to the interrogator, a method for efficiently tuning and assuring accuracy of the tag's transmit frequency in responding to the interrogator, comprising:

• (a) for an initial period of production of RF ID tags, as each of many series of tags is produced on a wafer, roughly setting the transmit frequency of each tag to a gross frequency range for all tags, by measuring a characteristic of a circuit component in the tag that affects transmit frequency and roughly tuning based on this characteristic in a testing phase of manufacture,
• (b) at the point of application of the tags to products or product containers, fine tuning each tag's transmit frequency over the air by sending an interrogating signal within the gross frequency range to the tag and detecting a response from the tag, measuring the frequency of the response, determining a frequency adjustment amount for each tag, and sending a further signal within the gross frequency range to each tag to set bits in a nonvolatile element of the tag circuitry to adjust the tag substantially to the desired tag transmit frequency, and
• (c) applying a plurality of the tags to products or containers, at the point of application;
• (d) for said initial period of production of the RF ID tags, monitoring the actual transmit frequency of each tag, or of a sampling of tags or selective wafer probing, as measured at the point of application prior to fine tuning, and using this information, making adjustments to the process of production of the tags on the wafers to improve the accuracy of the transmit frequency toward the desired tag transmit frequency, and continuing to adjust the process of production of the tags until a target percentage is achieved of tags having a transmit frequency within said gross frequency range before any rough tuning of tags during production as in step (a), and
• (e) after said target percentage has been achieved in the initial period of production of the RF ID tags, discontinuing all testing of tags during the wafer production and relying on the integrated circuitry of the tags as produced, continuing to fine tune the transmit frequency of the tags at the point of application of the tags, with discarding of tags that fail to fine tune to the desired transmit frequency at the point of application.