Production of radio frequency ID tags
First Claim
1. In the production of a radio frequency ID tag, of the type that receives and stores RF energy from an interrogator and uses that energy for the transmission of a responding signal, a method for imposing a randomized transmit time delay on each tag manufactured, such time delay being different for essentially every tag to avoid simultaneous responsive transmission by multiple tags, comprising:
- including a non-volatile settable element in an integrated circuit of the tag, with a computer in the manufacturing process, generating a pseudo-random number using an algorithm, such pseudo-random number essentially being different for each tag in a batch of tags for a particular application, and placing such a pseudo-random number in the non-volatile element of each such tag, such number controlling the transmit time delay for responding transmission of each tag, whereby no random number generator is needed onboard the tag.
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Accused Products
Abstract
A radio frequency ID tag, very small in size and with an onboard antenna, is manufactured, tested and applied cost-efficiently. The transmit frequency for the tag is set during manufacture approximately, within a selected range, in a gross tuning step. The gross calibration is based on one or more measured characteristics of electronic componentry on wafers, and based on such measured characteristics, the chips can be grossly calibrated and parallel so that all tags will be within a fairly close tolerance of the target transmit frequency. A second tuning step fine tunes each tag by RF communication to set values of capacitance, resistance, etc., and this can be at the point of application of the tags. Other disclosed aspects of the invention also add to economy of producing the tag and reliability of the tags in service.
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Citations
23 Claims
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1. In the production of a radio frequency ID tag, of the type that receives and stores RF energy from an interrogator and uses that energy for the transmission of a responding signal, a method for imposing a randomized transmit time delay on each tag manufactured, such time delay being different for essentially every tag to avoid simultaneous responsive transmission by multiple tags, comprising:
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including a non-volatile settable element in an integrated circuit of the tag, with a computer in the manufacturing process, generating a pseudo-random number using an algorithm, such pseudo-random number essentially being different for each tag in a batch of tags for a particular application, and placing such a pseudo-random number in the non-volatile element of each such tag, such number controlling the transmit time delay for responding transmission of each tag, whereby no random number generator is needed onboard the tag. - View Dependent Claims (2, 3, 4)
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5. 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 an interrogator, comprising:
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in manufacture of a series of tags on a wafer, only roughly setting the transmit frequency 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, 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 non-volatile element of the tag circuitry to adjust the tag substantially to the desired tag transmit frequency, and applying a plurality of the tags to products or containers, at the point of application. - View Dependent Claims (6, 7, 8, 9, 10, 11, 12, 13, 14, 15)
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16. A method for producing and testing a multiplicity of integrated circuits, comprising:
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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, and 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. - View Dependent Claims (17, 18, 19, 20)
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21. 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:
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(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 non-volatile 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. - View Dependent Claims (22, 23)
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Specification