Coupling probe for micro device detection
By using capacitively coupled probes and series switches, the problem of difficult measurement of micro-devices was solved, achieving efficient and reliable measurement results, reducing costs and improving measurement accuracy.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- VUEREAL INC
- Filing Date
- 2021-03-10
- Publication Date
- 2026-07-10
AI Technical Summary
Existing technologies are difficult to efficiently measure a large number of micro-devices, especially since the small size and large number of devices make contact measurement difficult, and post-processing steps increase costs and defects.
Using a capacitively coupled probe, a time-varying stimulation signal is applied between the contacts of the micro-device and the common electrode. The positive or negative slope of the signal is used to activate the device function, and the bias state of the device is controlled by a series switch to prevent the reset function from pushing the device into an unrecoverable state.
It enables efficient and reliable measurement of micro-devices, reduces measurement costs, improves measurement accuracy, and avoids device damage.
Smart Images
Figure CN115210582B_ABST
Abstract
Description
Technical Field
[0001] This invention relates to probes designed for measuring cycles of microdevices. Summary of the Invention
[0002] Embodiments of the present invention relate to a coupling probe for measuring the cycle of a microdevice, the coupling probe comprising: an electrode made of a conductive layer covered by a dielectric for stimulating the microdevice; a stimulation capacitor formed of the conductive layer, the dielectric, and a device pad; a voltage stimulation source for stimulating the stimulation capacitor; and a switch configured in series to turn on the microdevice after a first active portion of the stimulation signal.
[0003] Another embodiment of the invention relates to a method for measuring the cycle of a microdevice using a non-contact probe, the method comprising: applying a time-varying stimulation voltage signal to a stimulation capacitor formed between at least one contact / pad of the microdevice and a common electrode; activating a function in the microdevice due to either a positive or negative slope of the stimulation voltage signal; and using a switch to keep the microdevice on after the active portion of the time-varying stimulation voltage signal.
[0004] Another embodiment of the invention relates to a method for measuring the cycle of a microdevice using a non-contact probe, the method comprising: applying a time-varying stimulation voltage signal to a stimulation capacitor formed between at least one contact / pad of the microdevice and a common electrode; activating a function in the microdevice due to either a positive or negative slope of the stimulation voltage signal; and increasing the amplitude of the active portion of the time-varying stimulation voltage signal after each cycle. Attached Figure Description
[0005] The foregoing and other advantages of the present invention will become apparent from reading the following detailed description and referring to the accompanying drawings.
[0006] Figure 1(a) illustrates an exemplary implementation of the probe and its position on the device during a measurement cycle.
[0007] Figure 1(b) shows another configuration in which a probe tip is used instead of a coupling probe electrode.
[0008] Figure 2 This shows V when the device is turned on. ST The positive slope.
[0009] Figure 3 The electrical structure of the probe is shown.
[0010] While the invention is readily adaptable to various modifications and alternatives, specific embodiments or implementations have been illustrated by way of example in the accompanying drawings and will be described in detail herein. However, it should be understood that this disclosure is not intended to limit it to the particular forms disclosed. Rather, this disclosure is intended to cover all modifications, equivalents, and alternatives falling within the spirit and scope of the invention as defined by the appended claims. Detailed Implementation
[0011] While specific embodiments and applications of the invention have been illustrated and described, it should be understood that the invention is not limited to the precise structure and composition disclosed herein, and various modifications, alterations and variations may be apparent from the foregoing description without departing from the spirit and scope of the invention as defined in the appended claims.
[0012] In this specification, the terms "device" and "microdevice" are used interchangeably. However, those skilled in the art will recognize that the embodiments described herein are independent of device size.
[0013] There is a need to measure microdevices across wafers to increase the yield of integrating functional microdevices into system substrates. The challenge is that the number of microdevices on the original (or donor) substrate is enormous, reaching hundreds of millions. Furthermore, the sheer size of these devices makes contact measurement extremely difficult. One solution is to perform post-processing on the microdevices and create larger pads using metal traces to form an array for measuring the microdevices. While this approach can be effective, the post-processing steps increase cost and defects.
[0014] In a first embodiment, capacitive coupling via a common electrode (made of a conductive layer covered by a dielectric) can be used to stimulate a group of microdevices (or one of the microdevices). The dielectric can be a thin film, an air gap, or a combination of both.
[0015] Here, a time-varying signal (stimulus signal) V is applied to the capacitor. ST The capacitor is formed between at least one contact / pad of the microdevice and a common electrode. Depending on the position of the capacitor relative to the current path through the device, either a positive or negative slope of the stimulus signal can activate a function in the microdevice. In this case, the slope is referred to as the active portion of the signal. The other portion of the signal is referred to as the reset portion. Depending on the function to be measured, the active or reset portion of the signal can be changed.
[0016] In some cases, the reset function can push a device into an unrecoverable state and activate it. For example, if the device is an LED with parasitic capacitance, the positive slope of the signal will inject current into the diode, and the voltage across the diode will stabilize at V. ON(It is a function of the injected current). After applying a negative slope, the voltage across the diode will shift to a very low value, and the next positive slope will not be able to raise that voltage to V. ON .
[0017] In addition to the first embodiment, to address this problem, a reset function can push the device into an unrecoverable state and be activated, switching the device to the stimulation signal V. ST Used in series. During the active portion of the signal, the signal is connected to the stimulation capacitor C. ST Furthermore, during the rest function (or a portion thereof), the signal is disconnected from the capacitor. Thus, the bias state of the device is controlled, where in one case the bias state is the voltage level at one or more contacts / pads of the device. In another case, the bias state can be the charge stored in the device capacitor or the stimulation capacitor.
[0018] In addition to the first embodiment, the value of the stimulation capacitor varies during the reset or active portion of the signal. In this way, the effect of each reset or active portion is controlled to ensure that the device is always set under good bias conditions.
[0019] This invention relates to the functionality of probes for microdevices. Figure 1(a) illustrates an exemplary specific implementation of the probe and its position on the device during a measurement cycle. In Figure 1(a) and Figure 3 In one implementation scheme given in the document, V ST It is a stimulus signal, C d It is a device capacitor, and C ST It is a stimulating capacitor. C ST It is formed of a conductive layer, a dielectric, and a device pad (entry pad) / contact. A pad (or probe buffer ring) may be present around the probe to accommodate the probe resting on top of the microdevice. The probe buffer ring / pad may also be conductive to couple with some contacts of the microdevice. The support pad may be a ring or other structure surrounding the probe or at other locations on the probe.
[0020] like Figure 1a , Figure 1b and Figure 3 The switch SW shown needs to ensure that the microdevice can be used as... Figure 2 The first active portion of the signal shown is then switched on. For example... Figure 2 The V shown ST The active slope is during the period when the device is on, and the reset slope is during the period when the device is off. Here, the active slope of the signal is positive.
[0021] Figure 1(b) shows an alternative configuration in which a probe tip is used instead of a coupling probe electrode. Here, a support pad protects the probe tip and the microdevice from unwanted stress.
[0022] The support pad can also be an active structure. Here, a sensor can be used as a reference surface or microdevice to identify the probe's position. The sensor can be based on capacitance, inductance, or waveform.
[0023] The probe structure of Figure 1(b) can be mounted in a leveling device. When the probe is brought close to the microdevice, if the probe is not flush with the microdevice substrate, a portion of the support pad can contact the microdevice substrate. Here, the leveling device can adjust the position of the probe to make it flush with the substrate. The leveling device can be passive, such as a gimbal, or it can be active using an actuator. The support pad can retract after leveling so that the probe (probe tip or coupling electrode) can contact or closely approach the microdevice. In one case, the support pad can be made of a soft material that retracts under pressure. In another related case, the support pad is active and uses an electroactive polymer actuator (piezoelectric or other type) for retraction. The support pad can retract completely or partially.
[0024] In addition to the first embodiment, to address this problem, a reset function can push the microdevice into an irreversible state and activate it, switching it to the stimulation signal V. ST Used in series. Here, the active signal can be V. ST The negative slope.
[0025] If switch SW is not present, then when V ST When there is a reset slope (negative slope in this case), it will push the device into a bias condition that makes it impossible to turn on the device using the same active portion of the signal (positive slope in this case).
[0026] In addition to the first embodiment, to address this problem, a reset function can push the device into an unrecoverable state and be activated, switching the device to the stimulation signal V. ST Used in series. Another approach is to increase V after each loop. ST The slope or amplitude of the active portion. It can be seen that this limits the number of times the device can be switched on.
[0027] In addition to the first embodiment, to address this problem, a reset function can push the device into an unrecoverable state and be activated, switching the device to the stimulation signal V. ST Used in series. The switch will V during the reset slope of this signal. ST Disconnect from the device. Therefore, the device state does not change; it can be turned on during the active portion of the signal without limiting the number of cycles.
[0028] In addition to the first embodiment, to address this problem, a reset function can push the device into an unrecoverable state and be activated, switching the device to the stimulation signal V. ST Used in series. During the active portion of the signal, the signal is connected to the stimulation capacitor C. ST C ST It can be a variable capacitor, so the effect of capacitor coupling on the device is reduced during the reset slope of the signal. Therefore, the bias state of the microdevice does not change significantly.
[0029] Method Implementation Plan
[0030] The present invention also describes a method for measuring the cycle of a microdevice using a coupling probe, comprising the steps of: applying a time-varying stimulation voltage signal to a stimulation capacitor formed between at least one contact or pad of the microdevice and a common electrode; activating a function in the microdevice due to either a positive or negative slope of the stimulation voltage signal; and using a switch to keep the microdevice on after the active portion of the time-varying stimulation voltage signal.
[0031] The present invention also describes a method for measuring the cycle of a microdevice using a coupling probe, comprising the steps of: applying a time-varying stimulation voltage signal to a stimulation capacitor formed between at least one contact / pad of the microdevice and a common electrode; activating a function in the microdevice due to either a positive or negative slope of the stimulation voltage signal; and increasing the amplitude of the active portion of the time-varying stimulation voltage signal after each cycle.
[0032] The probe switch disconnects the microdevice during the reset slope of the time-varying stimulation voltage signal, wherein the value of the stimulation capacitor varies during the reset slope or active portion of the time-varying stimulation voltage signal to control the effect of each reset slope or active portion, thereby keeping the microdevice under good bias conditions.
[0033] In one embodiment, the probe electrode is a common electrode of the microdevice, wherein the microdevice is connected to the stimulation capacitor during the active portion of the signal, and during the rest slope, the time-varying stimulation voltage signal is disconnected from the stimulation capacitor, such that the bias state of the microdevice is controlled, wherein in one case the bias state is a voltage level at one or more contacts or pads of the device.
[0034] In another embodiment, the probe electrode is a common electrode, wherein the microdevice is connected to the stimulation capacitor during the active portion of the signal, and during the rest slope, the time-varying stimulation voltage signal is disconnected from the stimulation capacitor, such that the bias state of the microdevice is controlled, wherein in one case the bias state is the charge stored in the stimulation capacitor.
[0035] In another embodiment, the probe electrode is a common electrode, wherein the microdevice is connected to the stimulation capacitor during the active portion of the signal, and during the rest slope, the time-varying stimulation voltage signal is disconnected from the stimulation capacitor, such that the bias state of the microdevice is controlled, wherein in one case the bias state is the charge stored in the device capacitor.
[0036] While the invention is readily adaptable to various modifications and alternatives, specific embodiments or implementations have been illustrated by way of example in the accompanying drawings and will be described in detail herein. However, it should be understood that this disclosure is not intended to limit it to the particular forms disclosed. Rather, this disclosure is intended to cover all modifications, equivalents, and alternatives falling within the spirit and scope of the invention as defined by the appended claims.
Claims
1. A coupling probe for measuring the cycles of a microdevice, the coupling probe comprising: Electrodes, which are made of a conductive layer covered by a dielectric, are used to stimulate the microdevice; A stimulation capacitor, the stimulation capacitor being formed of the conductive layer, the dielectric, and the device pad; A voltage stimulation source, wherein the voltage stimulation source is used to stimulate the stimulation capacitor; and A switch, connected in series, controls the bias condition of the microdevice to turn it on after the first active portion of the stimulus signal. The value of the stimulation capacitor varies during the reset slope or active portion of the time-varying stimulation voltage signal to control the effect of each reset slope or active portion, thereby keeping the microdevice under good bias conditions.
2. The coupling probe according to claim 1, wherein the dielectric is a thin film, an air gap, or a combination of both.
3. The coupling probe according to claim 1, wherein the electrode is the common electrode of the microdevice.
4. The coupling probe of claim 1, wherein the switch is a point at which the voltage stimulation source is disconnected from the microdevice during a portion of the reset slope of the stimulation signal.
5. The coupling probe of claim 1, wherein the stimulation capacitor is a variable capacitor for minimizing the effect of capacitor coupling on the microdevice during the reset slope of the time-varying stimulation voltage signal.
6. The coupling probe of claim 1, wherein the switch disconnects the microdevice during the reset slope of the time-varying stimulation voltage signal.
7. The coupling probe of claim 6, wherein in the active portion of the time-varying stimulation voltage signal, the microdevice is connected to the stimulation capacitor, and during the reset slope, the time-varying stimulation voltage signal is disconnected from the stimulation capacitor, such that the bias state of the microdevice is controlled, wherein in one case the bias state is a voltage level at at least one contact or pad of the microdevice.
8. The coupling probe of claim 6, wherein in the active portion of the time-varying stimulation voltage signal, the microdevice is connected to the stimulation capacitor, and during the reset slope, the time-varying stimulation voltage signal is disconnected from the stimulation capacitor, such that the bias state of the microdevice is controlled, wherein in one case the bias state is a charge stored in the stimulation capacitor.
9. The coupling probe of claim 6, wherein in the active portion of the time-varying stimulation voltage signal, the microdevice is connected to the stimulation capacitor, and during the reset slope, the time-varying stimulation voltage signal is disconnected from the stimulation capacitor, such that the bias state of the microdevice is controlled, wherein in one case the bias state is a charge stored in the device capacitor.
10. The coupling probe of claim 1, wherein the coupling probe rests on top of the microdevice on a support pad.
11. The coupling probe of claim 10, wherein the support pad is conductive to couple with one or more contacts of the microdevice.
12. The coupling probe of claim 10, wherein the support pad is a loop surrounding the coupling probe.
13. The coupling probe of claim 10, wherein the probe structure is mounted in a leveling device, and if the coupling probe is not flush with the microdevice substrate, a portion of the support pad contacts the microdevice substrate.
14. The coupling probe of claim 13, wherein the leveling device adjusts the position of the coupling probe to make the coupling probe flush with the microdevice substrate, and the support pad retracts after leveling to allow the probe tip or coupling electrode to contact or closely approach the microdevice.
15. The coupling probe of claim 13, wherein the support pad is fully or partially retracted.
16. The coupling probe of claim 13, wherein the leveling device is passive using a universal joint or active using an actuator.
17. The coupling probe of claim 10, wherein the support pad is active and uses an electroactive polymer actuator.
18. The coupling probe of claim 17, wherein the active support pad retracts during measurement to provide enhanced connectivity with the microdevice.
19. A method for measuring the cycle of a microdevice using a coupling probe, the method comprising: A time-varying stimulation voltage signal is applied to the stimulation capacitor of the coupling probe, the stimulation capacitor being formed between at least one contact or pad of the microdevice and a common electrode; The stimulation capacitor is stimulated using a voltage stimulation source; The function in the microdevice is activated by either the positive or negative slope of the time-varying stimulus voltage signal; and A switch is used to keep the microdevice on after the active portion of the time-varying stimulus voltage signal.
20. The method of claim 19, wherein the switch is a point at which the voltage stimulation source is disconnected from the microdevice during a portion of the reset slope of the time-varying stimulation voltage signal.
21. The method of claim 19, wherein the stimulation capacitor is a variable capacitor for minimizing the effect of capacitor coupling on the microdevice during the reset slope of the time-varying stimulation voltage signal.
22. The method of claim 19, wherein the switch disconnects the microdevice during the reset slope of the time-varying stimulus voltage signal.
23. The method of claim 19, wherein the value of the stimulation capacitor varies during the reset slope or active portion of the time-varying stimulation voltage signal to control the effect of each reset slope or active portion, thereby maintaining the microdevice under good bias conditions.
24. The method of claim 22, wherein in the active portion of the time-varying stimulation voltage signal, the microdevice is connected to the stimulation capacitor, and during the reset slope, the time-varying stimulation voltage signal is disconnected from the stimulation capacitor, such that the bias state of the microdevice is controlled, wherein in one case the bias state is a voltage level at at least one contact or pad of the microdevice.
25. The method of claim 22, wherein in the active portion of the time-varying stimulation voltage signal, the microdevice is connected to the stimulation capacitor, and during the reset slope, the time-varying stimulation voltage signal is disconnected from the stimulation capacitor, such that the bias state of the microdevice is controlled, wherein in one case the bias state is a charge stored in the stimulation capacitor.
26. The method of claim 22, wherein in the active portion of the time-varying stimulation voltage signal, the microdevice is connected to the stimulation capacitor, and during the reset slope, the time-varying stimulation voltage signal is disconnected from the stimulation capacitor, such that the bias state of the microdevice is controlled, wherein in one case the bias state is a charge stored in the device capacitor.
27. A method for measuring the cycle of a microdevice using a coupling probe, the method comprising: A time-varying stimulation voltage signal is applied to the stimulation capacitor of the coupling probe, the stimulation capacitor being formed between at least one contact or pad of the microdevice and a common electrode; The stimulation capacitor is stimulated using a voltage stimulation source; The function in the microdevice is activated by either the positive or negative slope of the time-varying stimulus voltage signal; A switch is used to keep the microdevice on after the active portion of the time-varying stimulus voltage signal; as well as After each cycle, the amplitude of the active portion of the time-varying stimulus voltage signal is increased.
28. The method of claim 27, wherein the switch is a point at which the voltage stimulation source is disconnected from the microdevice during a portion of the reset slope of the time-varying stimulation voltage signal.
29. The method of claim 27, wherein the stimulation capacitor is a variable capacitor for minimizing the effect of capacitor coupling on the microdevice during the reset slope of the time-varying stimulation voltage signal.
30. The method of claim 27, wherein the switch disconnects the microdevice during the reset slope of the time-varying stimulus voltage signal.
31. The method of claim 27, wherein the value of the stimulation capacitor varies during the reset slope or active portion of the time-varying stimulation voltage signal to control the effect of each reset slope or active portion, thereby maintaining the microdevice under good bias conditions.
32. The method of claim 30, wherein in the active portion of the time-varying stimulation voltage signal, the microdevice is connected to the stimulation capacitor, and during the reset slope, the time-varying stimulation voltage signal is disconnected from the stimulation capacitor, such that the bias state of the microdevice is controlled, wherein in one case the bias state is a voltage level at at least one contact or pad of the microdevice.
33. The method of claim 30, wherein in the active portion of the time-varying stimulation voltage signal, the microdevice is connected to the stimulation capacitor, and during the reset slope, the time-varying stimulation voltage signal is disconnected from the stimulation capacitor, such that the bias state of the microdevice is controlled, wherein in one case the bias state is a charge stored in the stimulation capacitor.
34. The method of claim 30, wherein in the active portion of the time-varying stimulation voltage signal, the microdevice is connected to the stimulation capacitor, and during the reset slope, the time-varying stimulation voltage signal is disconnected from the stimulation capacitor, such that the bias state of the microdevice is controlled, wherein in one case the bias state is a charge stored in the device capacitor.