RF COMMUNICATION DEVICE WITHOUT TEMPORARY CONNECTION LINE, AND MANUFACTURING METHOD

Abstract

It is described an RF communication device comprising: i) an RF antenna functionality; ii) at least one antenna pad connected to the RF antenna functionality; iii) a further functionality which is not an RF antenna functionality; and iv) at least one non-antenna pad electrically connected to the further functionality.

The antenna pad and the non-antenna pad are arranged to be short-circuited with each other, and the non-antenna pad is electrically connected via a connection line to the further functionality within the RF communication device.

Further, a method of manufacturing an RF communication device is described.

Claims

1-15. (canceled)

16. An RF communication device, comprising: an RF antenna functionality; at least one antenna pad connected to the RF antenna functionality; a further functionality which is not an RF antenna functionality; and at least one non-antenna pad electrically connected to the further functionality; wherein the antenna pad and the non-antenna pad are arranged to be short-circuited with each other; and wherein the non-antenna pad is electrically connected via a connection line to the further functionality within the RF communication device.

17. The RF communication device according to claim 16, wherein the electrical connection between the non-antenna pad and the further functionality is free of a temporary connection line.

18. The RF communication device according to claim 16, wherein the non-antenna pad comprises a test pad, and wherein the further functionality comprises a test circuit device.

19. The RF communication device according to claim 16, wherein the RF communication device is one of the group which consists of an RFID device, an RFID tag, an RFID IC.

20. The RF communication device according to claim 16, further comprising: a control element arranged at the connection line between the non-antenna pad and the further functionality.

21. The RF communication device according to claim 20, wherein the control element is configured to electrically connect the non-antenna pad and the further functionality in a first mode, and wherein the control element is configured to electrically disconnect the non-antenna pad and the further functionality in a second mode.

22. The RF communication device according to claim 21, wherein the first mode is a test mode, and wherein the second mode is a non-test mode.

23. The RF communication device according to claim 21, wherein the second mode is an RF communication mode, and wherein, during the RF communication mode, the non-antenna pad is electrically isolated from the further functionality.

24. The RF communication device according to claim 20, wherein the control element comprises a transmission gate or an inverter.

25. The RF communication device according to claim 20, wherein the control element comprises at least two transistors.

26. The RF communication device according to claim 25, wherein the at least two transistors comprise an NMOS transistor and a PMOS transistor.

27. The RF communication device according to claim 20, further comprising: a peak detector arranged between the non-antenna pad and the control element.

28. The RF communication device according to claim 27, wherein the peak detector comprises a positive peak detector element and a negative peak detector element.

29. The RF communication device according to claim 20, wherein the control element comprises a charge pump.

30. The RF communication device according to claim 16, further comprising: an antenna that is configured as a slit antenna with at least two segments, wherein the antenna pad and the non-antenna pad are connected to the same segment.

31. The RF communication device according to claim 30, wherein the antenna is configured as a single-slit antenna.

32. A method of manufacturing an RF communication device, the method comprising: providing a wafer with a plurality of RF communication device preforms, wherein the preforms respectively comprise: an RF antenna functionality, at least one antenna pad connected to the RF antenna functionality, a further functionality which is not an RF antenna functionality, and at least one non-antenna pad electrically connected to the further functionality; connecting, within the RF communication device preforms, the non-antenna pad electrically via a connection line to the further functionality; separating the wafer into a plurality of RF communication devices.

33. The method according to claim 32, wherein the wafer is free of a temporary connection line, which temporary connection line is disconnected during the separating, between the non-antenna pad and the further functionality.

34. A method of using a connection line, arranged completely within an RF communication device between a non-antenna pad and a non-antenna functionality, in order to substitute for a partially external temporary connection line.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0035] FIG. 1 illustrates an RF communication device according to an exemplary embodiment of the present disclosure.

[0036] FIG. 2 illustrates an RF communication device with a single slit antenna according to an exemplary embodiment of the present disclosure.

[0037] FIGS. 3 to 5 illustrate respectively an RF communication device with a control element according to exemplary embodiments of the present disclosure.

[0038] FIG. 6 illustrates an RF communication device with a charge pump according to an exemplary embodiment of the present disclosure.

[0039] FIG. 7 illustrates an RF communication device with a peak detector according to an exemplary embodiment of the present disclosure.

[0040] FIG. 8 illustrates an RF communication device with a positive peak detector element and a negative peak detector element according to an exemplary embodiment of the present disclosure.

[0041] FIG. 9 illustrates a waveform at an antenna pad of an RF communication device according to an exemplary embodiment of the present disclosure.

[0042] FIG. 10 illustrates a conventional RFID chip.

[0043] FIG. 11 illustrates a conventional wafer with external temporary connection lines.

[0044] FIG. 12 illustrates a conventional RFID chip preform with an external temporary connection line.

[0045] The illustrations in the drawings are schematic. In different drawings, similar or identical elements are provided with the same reference signs.

DETAILED DESCRIPTION OF THE DRAWINGS

[0046] Before, referring to the drawings, an exemplary embodiment will be described in further detail, and some basic considerations will be summarized based on which embodiments of the disclosure have been developed.

[0047] According to an exemplary embodiment, there is described a single-slit antenna solution is an RFID assembly technology which can enable easier and low cost antenna designs. In this assembly solution, one or more non-antenna pads of the RFID chip (RF communication device) are shorted-circuited to the RF pads (antenna pads). In the state-of-the-art single-slit antenna solution implementation, the non-antenna pads short-circuited to the RF pads are electrically disconnected and therefore can be safely short-circuited to the RF pads. The connection from the non-antenna pads to the internal nodes (test circuitry) of the chip is done via the scribe lines (separation between adjacent chips) of the semiconductor wafer and broken after the dicing step. This connection is referred here as “saw bow connection” (temporary connection line). The present disclosure is about an electrical circuitry that allows the removal of the saw bow but keeping its functionality. In addition, it may enable smaller scribe lines being beneficial for next generation dicing techniques. This novel approach is isolating the RF signals to the internal nodes through the non-antenna pads allowing them to be short-circuited to the RF pads safely. A challenge of passive RFID tags may be seen in blocking the RF signal before being powered. It may be desirable to electrically isolate RF signals from a pad to an internal node, controlled by a passive device.

[0048] FIG. 1 illustrates an RF communication device 100 (in this example an RFID IC of an RFID tag) according to an exemplary embodiment of the present disclosure. The RF communication device 100 comprises an RF antenna functionality 115 with an RF front-end, a data modulator, a data demodulator, a digital control, and a memory. Two antenna pads 110 are connected to the RF antenna functionality 115. The RF communication device 100 further comprises a further functionality 125 (in the example shown a test circuit) which is not an RF antenna functionality. Two non-antenna pads 120 (test pads) are electrically connected to the further functionality 125. The antenna pad 110 and the non-antenna pad 120 are arranged to be short-circuited with each other (not shown, see FIG. 2 below). The non-antenna pads 120 are electrically connected via a connection line 130 to the further functionality 125, respectively, within the RF communication device 100. It can be seen that the electrical connection 130 between the non-antenna pads 120 and the further functionality 125 is free of a partially (chip-) external temporary connection line 230 (compare the conventional examples in FIGS. 10 to 12 above).

[0049] FIG. 2 illustrates an RF communication device 100 with a single slit antenna design according to an exemplary embodiment of the present disclosure. The RF communication device 100 further comprises an antenna 116 with two antenna segments 116a, 116b which are divided by a slit. The segments 116a, 116b hereby form diploes of the antenna 116. A first antenna pad 110 and a first non-antenna pad 120 are short-circuited within a common pad that is coupled to the first antenna segment 116a. A second antenna pad 110 and a second non-antenna pad 120 are short-circuited in a further common pad that is coupled to the second antenna segment 116b.

[0050] FIG. 3 illustrates an RF communication device 100 with a control element 150 according to an exemplary embodiment of the present disclosure. The control element 150 is implement with two transistors 151, 152, being an NMOS 152 and a PMOS 151 transistor, that implement an inverter function. If a control signal is “0”, the non-antenna pad 120 is bypassed through the PMOS 151 and connected to the test circuitry 125. If the control signal is “1”, the test circuitry 125 is isolated from the non-antenna pad 120 and the node is pulled-down. Control signal being “1” would be an isolated mode (isolating TP2/circuitry) and “0” a connection (test) mode.

[0051] Connected mode: control signal starts “1” and later is moved to “0”, connecting the non-antenna pad 120 and the test circuitry 125. The supply voltage, which sets “1” of control signal, is generated from a stimulus at the non-antenna pad 120. There is a voltage drop between the non-antenna pad 120 voltage and supply voltage, which is caused by the PMOS Vth, in a way the supply voltage and control, if “1” logic, can be increased by increasing the non-antenna pad 120 voltage. If the non-antenna pad 120 voltage is increased, the voltage also increases and once it achieves the control circuit threshold, the control signal is de-asserted “0”, thereby connecting the non-antenna pad 120 to the test circuit 125, thus allowing testability.

[0052] Isolated mode (RF communication mode): the control signal starts “1” and it keeps “1”. Supply voltage is generated through the RF front-end and the supply voltage is high enough to block the RF signal present at the non-antenna pad 120. In other words, the control signal, which is defined by the supply voltage being higher than the RF signal at the non-antenna pad 120, is applied in a way that the RF signal can be isolated by the PMOS 151.

[0053] In other words, the control element 150 is configured to electrically connect the non-antenna pad 120 and the further functionality 125 in a first mode, in particular a test mode (connection mode), and the control element 150 is configured to electrically disconnect the non-antenna pad 120 and the further functionality 125 in a second mode, in particular a non-test mode (isolated mode). The second mode is an RF communication mode, and, during the RF communication mode, the non-antenna pad 120 is electrically isolated from the further functionality 125.

[0054] FIG. 4 illustrates an RF communication device 100 with a control element 150 according to an exemplary embodiment of the present disclosure. The control element 150 is implemented as a transmission gate between the non-antenna pad 120 and the test circuit 125, including IO buffer 126 and analog-multiplexer (mux) block 128. Reference sign 180 denotes the border between device 100 and scribe line. In test mode, the control element 150 is enabled and the test circuit 125 is connected to the non-antenna pad 120. After the antenna assembly, since the chip is no more tested, the control element 150 is disabled, thereby isolating the test circuit 125 from the non-antenna pad 120, and consequently, also isolating the test circuit 125 from the antenna pad 110.

[0055] Once the control element 150 circuit has less load (capacitive and resistive) compared with the test circuit 125, the introduction of the control element 150 contributes to minimize the impact of the removal of the temporary connection line 230 over chip parameters like impedance and power.

[0056] FIG. 5 illustrates an RF communication device 100 with a control element 150 according to an exemplary embodiment of the present disclosure. The design is similar to the one showed in FIG. 4, the difference being that the TO buffer block 126 is omitted by simplicity and the analog-mux 128 is shown in more detail.

[0057] FIG. 6 illustrates an RF communication device 100 with a charge pump 170 according to an exemplary embodiment of the present disclosure. The design is very similar to the one shown in FIG. 4 with the difference being that a charge pump 170 is connected to the transmission gate 150. The application of the charge pump 170 is to provide a proper bias voltage to the bulk terminals of the devices of the transmission gate, in a way the parasitic devices inherent to the MOS transistors (151 and 152 in FIG. 6), like diodes and bipolar transistors, are prevented to be triggered.

[0058] FIG. 7 illustrates an RF communication device 100 with an additional peak detector 160, between the non-antenna pad 120 and the control element 150, according to an exemplary embodiment of the present disclosure. The application of the peak detector 160 can also decrease an undesired negative voltage at the test circuit 125, in particular the analog-mux 128.

[0059] FIG. 8 illustrates an RF communication device 100 with a positive peak detector element 165 and a negative peak detector element 166 according to an exemplary embodiment of the present disclosure. The design is very similar to the one shown in FIG. 7 with the difference being that the peak detector 160 comprises a positive peak detector element 165 and a negative peak detector element 166.

[0060] FIG. 9 illustrates a waveform (voltage vs. time) at power-up, for example according to the embodiment described in FIG. 8 above. The voltage at the RF antenna pads 110 starts to grow, and then stabilizes. This is the typical power-up behavior when a reader is turned-on and RFID tags in the same region of the reader are energized. It can be seen that, even though the antenna pad 110 and the non-antenna pad 120 are short-circuited, the waveform is as expected and desired (no negative impact from the non-antenna pad 110 to further functionality 125 connection 130).

[0061] In this specification, embodiments have been presented in terms of a selected set of details. However, a person of ordinary skill in the art would understand that many other embodiments may be practiced which include a different selected set of these details. It is intended that the following claims cover all possible embodiments.

REFERENCE NUMERALS

[0062] 100 RF communication device, RFID tag [0063] 110 Antenna pad (RF pad) [0064] 115 Antenna functionality (antenna-related device) [0065] 116 Antenna [0066] 116a First segment [0067] 116b Second segment [0068] 120 Non-antenna pad (test pad) [0069] 125 Non-antenna functionality (non-antenna-related device, test circuitry) [0070] 126 IO buffer [0071] 128 Analog Multiplexer (MUX) [0072] 130 Connection line [0073] 150 Control element [0074] 151 First transistor [0075] 152 Second transistor [0076] 160 Peak detector [0077] 165 Positive peak detector element [0078] 166 Negative peak detector element [0079] 170 Charge pump [0080] 180 Separation line, scribe line [0081] 200 Conventional RFID chip [0082] 201 Conventional wafer [0083] 210 Conventional RF pad [0084] 215 Conventional antenna functionality [0085] 220 Conventional test pad [0086] 225 Conventional test circuitry [0087] 230 Conventional saw bow [0088] 280 Conventional scribe line