Probe structures for microdevice inspection

Abstract

A probe card assembly includes: a substrate; one or more probe units in contact with the substrate, each probe unit including: an electrode integrated on the substrate; a bridge formed on the electrode to include a force sensor; a probe having a probe tip connected to the bridge, the probe biased to allow measurement of at least one property of a microdevice disposed on a wafer. The probe array in the probe card is used to test a microdevice by: aligning the array with a corresponding microdevice on a substrate; moving the probe card to the microdevice; biasing at least one probe to allow measurement of at least one property of the microdevice; monitoring a change in at least one property; and detecting connection of the microdevice by the change in at least one property of the microdevice.

Description

[0001] CROSS REFERENCE TO RELATED APPLICATIONS

[0002] This application claims priority to and the benefit of U.S. Provisional Patent Application No. 62 / 808,593, filed on February 21, 2019, which is hereby incorporated by reference in its entirety. Technical Field

[0003] The present disclosure relates to a wafer inspection apparatus including an improved probe card assembly. Background Art

[0004] Generally, a probe card is used to test a wafer of a semiconductor chip. During the positioning of the probe card over the wafer, the probe card sometimes fails to make uniform contact with the wafer and becomes tilted. It is desirable to provide an improved probe card assembly to achieve uniform contact with the wafer. Summary of the invention

[0005] According to one embodiment, a probe card assembly is provided. The probe card assembly includes: a substrate; one or more probe units in contact with the substrate, wherein each probe unit includes: a force sensor or electrode integrated on the substrate; a bridge formed on or above the force sensor; and a probe having a probe tip connected to the bridge, wherein the probe is biased to allow measurement of at least one property of a microdevice disposed on a wafer.

[0006] According to another embodiment, a method for testing an array of microdevices is provided, comprising: providing an array of probes in a probe card; aligning the probe array with corresponding microdevices on a substrate; moving the probe card to the microdevices; biasing at least one probe to allow measurement of at least one property of the at least one microdevice; monitoring changes in at least one property of the microdevice; and detecting connection of the microdevice through the change in at least one property of the microdevice.

[0007] According to some embodiments, a method for planarizing a wafer of microdevices for testing may be provided, the method comprising: providing at least one support for at least one probe unit connected to the wafer; aligning a corresponding area of ​​the wafer that does not have a microdevice to be tested to the at least one support; and pushing the corresponding area using the support. BRIEF DESCRIPTION OF THE DRAWINGS

[0008] The foregoing and other advantages of the present disclosure will become apparent after reading the following detailed description and referring to the accompanying drawings.

[0009] Figure 1 A cross-sectional view of a probe card assembly according to an embodiment of the present invention is illustrated.

[0010] Figure 2 The arrangement of force electrodes with probe units in a grid is illustrated.

[0011] Figure 3 A cross-sectional view of a probe card assembly according to an embodiment of the present invention is illustrated.

[0012] Figure 4 The arrangement of force electrodes and test electrodes in a grid is described.

[0013] Figure 5 Illustrate the different zones of the wafer.

[0014] Figure 6 Instructions Use support to push the wafer to become flat.

[0015] Although the present disclosure is susceptible to various modifications and alternative forms, specific embodiments or implementations have been shown by way of example in the drawings and will be described in detail herein. However, it should be understood that the present invention is not intended to be limited to the specific forms disclosed. Instead, the present disclosure will cover all modifications, equivalents, and alternatives that fall within the spirit and scope of the present invention as defined by the appended claims. DETAILED DESCRIPTION

[0016] Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs.

[0017] As used in the specification and claims, the singular form "a," "an," and "the" include plural references unless the context clearly dictates otherwise.

[0018] The term "comprising" as used herein will be understood to mean that the following list is non-exhaustive and may or may not include any other additional suitable items, such as one or more further features, components and / or elements (as appropriate). The terms "microdevice", "microLED" all refer to examples of semiconductor chips.

[0019] Generally, probe cards are used to test a wafer of semiconductor chips. During positioning of the probe card over the wafer, the probe card may not be in uniform contact with the wafer and become tilted. There is a need to provide an improved probe assembly / unit that uniformly senses the contact of the probe with the wafer.

[0020] According to one embodiment, an improved probe card assembly is provided.

[0021] According to another embodiment, a probe card assembly includes a substrate and one or more probe units in contact with the substrate.

[0022] In one case, each probe unit includes a force sensor / electrode integrated on the substrate. In another case, the force sensor or electrode may be part of the probe tip.

[0023] According to some embodiments, a bridge may be formed over the force sensor. The bridge may have one or more conductive layers. The bridge may include a first conductive layer for generating capacitance using the force sensor and a second conductive layer for connecting the probe tip to a signal. The first conductive layer and the second conductive layer may be the same or different layers.

[0024] In one embodiment, a dielectric layer may be disposed between the force sensor and the bridge.

[0025] In another embodiment, the bridge may have more than one probe tip with more than one electrode to connect it to a signal.The bridge may be a combination of dielectric and conductive layers.

[0026] In one case, when the probe tip touches a contact on a microdevice or substrate, the bridge deforms, thereby changing the capacitance between the force electrode and the conductive layer on the bridge. This change can be used to calibrate the force applied to the probe. In another case, the deformation of the bridge changes the resistance of the conductive layer on the bridge, which can be measured to extract the force applied to the probe.

[0027] According to yet other embodiments, when the probe tip touches the microdevice on the substrate, the bridge can be deformed so that an electrical property of the probe changes. The electrical property includes a capacitance change or a resistance change between the force sensor and the first conductive layer of the bridge.

[0028] In one instance, a change in an electrical property is used to identify a connection between the microdevice and the probe tip when a force is applied to the microdevice.

[0029] According to another embodiment, the contact between the probe tip and the microdevice can be periodically checked while the probe card is pushed toward the device. The probe can be biased to allow at least one property of the microdevice to be measured and the monitoring to see changes in at least one property of the microdevice. Changes in at least one property of the microdevice in different areas of the probe card can identify connected areas and unconnected areas.

[0030] In another embodiment, a method for testing an array of microdevices may include the steps of: 1) moving a probe card toward the microdevice while biasing the probes to allow measurement of at least one property of the microdevice without damaging the microdevice; 2) monitoring at least one property of the microdevice in different regions associated with the probe card as the probes move toward the microdevice; and 3) if a change in at least one property related to electrical coupling occurs in one or more regions, moving other regions toward the microdevice and stopping movement of the coupled regions.

[0031] In one case, in response to not having a connection between the probe tip and the microdevice in some areas, the probe can be tilted toward the unconnected area. This applies to a single tip or an array of tips.

[0032] In one case, changes in capacitance or resistance can be used to detect defective microdevices on a substrate.

[0033] In another case, the change in capacitance / resistance can be used to detect the uniformity of the probe card.The signals can be connected vertically, horizontally, or in another cluster format.

[0034] According to yet another embodiment, the connection test probe tip can be set on different areas (e.g., corners or edges) to detect contact. If the connection test probe is connected to the wafer in some areas and not connected to the wafer in other areas, the probe card can be tilted toward the unconnected area.

[0035] In one case, a support may be used to push the wafer to make it flat. In one case, a different zone may be provided for each probe, wherein each probe may cover a zone or one probe may move between zones.

[0036] In another case, at least one support may be provided with a probe unit.The support may be aligned with the wafer to cover the inactive area (ie, the area not to be tested) and the support may approach the wafer and push the wafer to make it flat.

[0037] Various embodiments according to the current structures and processes provided are described in more detail below.

[0038] refer to Figure 1 , illustrating a probe card assembly 100. The probe card assembly includes a substrate 102. The substrate may be made of glass, sapphire or other materials. The substrate 102 may have one or more probe units (112, 114) in contact with the substrate. Each probe unit (112, 114) may include a force sensor or electrode 106 integrated on the substrate. A dielectric layer 108 may be disposed above the force electrode / sensor 106. A bridge 110 may be formed on or above the force electrode 106. A probe 104 having a probe tip may be connected to the bridge 110. The bridge has one or more conductive layers. In one case, the bridge may include a first conductive layer to generate capacitance using the force electrode / sensor 106. In another case, the bridge may include a second conductive layer that connects the probe tip to a microdevice on a wafer to generate a signal. The first conductive layer and the second conductive layer may be the same or different layers. In one case, the force electrode / sensor 106 may be a portion of the probe tip. The bridge 110 may have more than one probe tip with more than one force electrode / sensor to connect it to the signal. In one embodiment, the probe is biased to allow measurement of electrical properties of microdevices disposed on a wafer.

[0039] When the probe tip contacts the microdevice, the bridge deforms and changes the electrical properties of the probe. The change in electrical properties may include a change in capacitance or resistance between the force electrode / sensor and the bridge. The change in electrical properties may be used to identify the connection between the microdevice and the probe tip when a force is applied to the microdevice.

[0040] In one embodiment, when the probe tip contacts the microdevice or substrate, the bridge can deform due to a change in capacitance between the force electrode and the electrode on the bridge. The change in capacitance can be used to calibrate the force applied to the probe. In another case, the deflection of the bridge changes the resistance of the conductive layer of the bridge.

[0041] In another embodiment, the connection between the probe tip and the microdevice can be monitored periodically as the probe is pushed toward the device. The connection in different areas can be measured. If some areas are connected and some areas are not connected, then the probe card is tilted toward the unconnected areas.

[0042] Also, the connection test probe tip may be disposed on an area where the probe is connected to the micro device. The connection test probe tip may be disposed on a corner of the probe card.

[0043] refer to Figure 2 , an arrangement of force electrodes with probe units in a grid may be provided. Grid 208 shows a plurality of force electrodes 204 arranged in columns on the probe units. A plurality of probe electrodes 206 may be formed in rows. The probe electrodes in at least one row may be activated and capacitance / resistance may be detected from the force electrodes. Thus, a change in capacitance / resistance of the force electrodes may be associated with the row. Activation may be rotated through different rows. A plurality of probe units 206 may be disposed on a substrate. In one case, the force electrodes 204 may be part of a probe tip of a probe. In one embodiment, different arrangements of force electrodes with probe units in a grid may be provided. The signal may be connected vertically, horizontally, or in another cluster format.

[0044] refer to Figure 3 , two alternative methods of providing the probe card assembly are available. Figure 1In case 1 discussed in , the probe card assembly includes a substrate 102. The substrate may be made of glass, sapphire or other materials. The substrate 102 may have one or more probe units (120, 130) in contact with the substrate. Each probe unit (120, 130) may include a force sensor or electrode 106 integrated on the substrate. A dielectric layer 108 may be disposed above the force electrode / sensor 106. A bridge 110 may be formed on or above the force electrode 106. A probe 112 having a probe tip may be connected to the bridge 110. The bridge has one or more conductive layers. In one case, the bridge may include a first conductive layer to generate capacitance using the force electrode / sensor 106. In another case, the bridge may include a second conductive layer that connects the probe tip to a microdevice on a wafer to generate a signal. The first conductive layer and the second conductive layer may be the same or different layers. In one case, the force electrode / sensor 106 may be part of the probe tip. The bridge 110 may have more than one probe tip with more than one force electrode / sensor to connect it to a signal.

[0045] In another case (Case 2), only a single bridge 310 is provided to connect one or more probes (304, 306) on the substrate 302. Here, more than one probe (304, 306) is formed on top of the bridge 310 and the electrodes 308 on the bridge can be patterned to provide independent connections to each probe when needed.

[0046] refer to Figure 4 , the test electrodes (406, 404, 402) may be arranged to connect the test probe tips on the areas where the probes are connected to the microdevices. In one case, the connection test probe tips may be arranged on different areas (e.g., on corners or edges) to detect contact. If the connection test probes are connected to the wafer in some areas and not connected to the wafer in other areas, the probe card may be tilted toward the unconnected areas.

[0047] refer to Figure 5, the wafer / substrate 500 may be provided with different zones 502. Each zone may be provided with a probe having a probe tip to test the microdevice on the wafer. In one case, the probe may cover one zone, or it may cover all zones divided on the wafer. The probe may move between different zones. To test the microdevice on the wafer, a probe array may be provided in a probe card. The probe may be aligned to the corresponding microdevice on the wafer / substrate. The probe card may be moved to the microdevice. One or more probes may be biased to allow measurement of at least one property of at least one microdevice. The probe may be periodically monitored to monitor changes in at least one property of the microdevice and the connection of the microdevice may be detected by changes in at least one property of the microdevice. Changes in at least one property of the microdevice in different regions of the probe card may identify connected regions and unconnected regions. In response to the lack of connection between the probe tip and the microdevice at some regions, the probe may be tilted toward the unconnected region.

[0048] refer to Figure 6 , supports may be provided to flatten the wafer. Since the wafer 610 may have bending or deformation due to stress, it may be challenging to probe a relatively large area using a probe card, especially for fine probe tips. In one case, at least one support 602 may be provided with a probe unit (604, 606). There may be more than one support around the probe unit. The probe unit includes at least one force sensor integrated on a substrate, a dielectric layer above the force electrode / sensor, and a bridge may be formed on or above the force electrode. The probe has a probe tip that can be connected to the bridge. The bridge has one or more conductive layers.

[0049] In one embodiment, the support 602 can be aligned with the wafer 610 to cover the inactive area (i.e., the area that will not be tested) and the support can be close to the wafer 610 and push the wafer to make it flat. In one case, the probe card can be moved between different zones of the wafer generated by the support. In another case, a different probe card can be used for each zone. In response to not having a connection between the probe tip and the microdevice at some areas, the support can be used to tilt the probe toward the unconnected area.

[0050] According to one embodiment, a probe card assembly may be provided. The probe card assembly may include: a substrate; one or more probe units in contact with the substrate, wherein each probe unit includes: a force sensor or electrode integrated on the substrate; a bridge formed on or above the force sensor; and a probe having a probe tip connected to the bridge, wherein the probe is biased to allow measurement of at least one property of a microdevice disposed on a wafer.

[0051] According to another embodiment, a dielectric layer may be sandwiched between the force sensor and the bridge. The bridge may include a first conductive layer for generating capacitance using the force sensor and a second conductive layer connecting the probe tip to the signal. The first conductive layer and the second conductive layer are the same or different layers.

[0052] According to some embodiments, when the probe tip contacts the microdevice, the bridge is deformable and changes the electrical properties of the probe. The change in electrical properties includes a change in capacitance or resistance between the force sensor and the first conductive layer of the bridge.

[0053] According to another embodiment, the change in electrical characteristics is used to identify the connection between the microdevice and the probe tip when a force is applied to the microdevice. In response to not having a connection between the probe tip and the microdevice at some areas, the probe can be tilted toward the unconnected area. The connection test probe tip can be set on the area where the probe is connected to the microdevice.

[0054] According to some embodiments, a method for testing an array of microdevices may be provided. The method may include: providing a probe array in a probe card; aligning the probe array with corresponding microdevices on a substrate; moving the probe card to the microdevices; biasing one or more probes to allow measurement of at least one property of at least one microdevice; monitoring changes in at least one property of the microdevice; and detecting connection of the microdevice by the change in at least one property of the microdevice. Biasing one or more probes at different regions of the probe card.

[0055] According to another embodiment, changes in at least one property of the microdevice in different regions of the probe card identify connected regions and unconnected regions. In response to not having a connection between the probe tip and the microdevice at some regions, the probe can be tilted toward the unconnected region.

[0056] According to some embodiments, monitoring a change in at least one property of the microdevice may include monitoring a change in capacitance or resistance.One or more force electrodes may be used with one or more probes to detect connections.

[0057] According to one embodiment, a method for planarizing a wafer of microdevices for testing is provided, comprising: providing at least one support for at least one probe unit connected to the wafer; aligning a corresponding area of ​​the wafer that does not have a microdevice to be tested to the at least one support; and using the support to push the corresponding area.

[0058] According to another embodiment, at least one support can generate different zones, and each zone has a probe card covering said zone to test microdevices. In another case, a single probe card is moved between different zones of the wafer generated by at least one support.

[0059] In one case, there is a dielectric between the conductive portion of the probe and the contact point of the semiconductor chip. Here, the signal is capacitively or inductively coupled between the probe and the semiconductor chip.

[0060] Although the present disclosure is susceptible to various modifications and alternative forms, specific embodiments or implementations have been shown by way of example in the drawings and described in detail herein. However, it should be understood that the present disclosure is not intended to be limited to the specific forms disclosed. Instead, the present disclosure will cover all modifications, equivalents, and alternatives that fall within the spirit and scope of the present invention as defined by the appended claims.

Claims

1. A probe card assembly, comprising: substrate; One or more probe units in contact with the substrate, wherein each probe unit comprises: A force sensor or electrode integrated on the substrate; a bridge formed over the force sensor or electrode; and A probe is formed on the bridge and has a probe tip connected to the bridge, wherein the probe is biased to allow measurement of at least one property of a microdevice disposed on a wafer.

2. The probe card assembly according to claim 1, further comprising: A dielectric layer is sandwiched between the force sensor and the bridge. 3 . The probe card assembly of claim 1 , wherein the bridge comprises a first conductive layer to generate capacitance using the force sensor. 4 . The probe card assembly of claim 3 , wherein the bridge comprises a second conductive layer connecting the probe tip to a signal. 5 . The probe card assembly of claim 4 , wherein the first conductive layer and the second conductive layer are the same or different layers.

6. The probe card assembly of claim 3, wherein when the probe tip contacts the microdevice, the bridge deforms, which changes an electrical property of the probe.

7. The probe card assembly of claim 6, wherein the change in electrical characteristics comprises a change in capacitance between the force sensor and the first conductive layer of the bridge.

8. The probe card assembly of claim 6, wherein the change in electrical characteristics comprises a change in resistance between the force sensor and the first conductive layer of the bridge.

9. The probe card assembly of claim 6, wherein the change in electrical characteristics is used to identify a connection between the microdevice and the probe tip when a force is applied to the microdevice. 10 . The probe card assembly of claim 9 , wherein in response to having no connection between the probe tip and the microdevice at an area, the probe tip tilts toward an unconnected area.

11. The probe card assembly of claim 1 , further comprising: A test probe tip is attached over the area where the probe is attached to the microdevice.

12. The probe card assembly of claim 1, wherein the force sensor or electrode may be part of the probe tip.

13. The probe card assembly of claim 7, wherein the change in capacitance is used to calibrate a force applied to the probe.

14. The probe card assembly of claim 6, wherein the deformation of the bridge changes the resistance of the first conductive layer on the bridge, which can be measured to extract the force applied to the probe.

15. The probe card assembly of claim 6, wherein the change in electrical characteristics is used to detect uniformity of the probe card.

16. The probe card assembly of claim 6, wherein the contact between the probe tip and the microdevice is periodically checked while the probe card is pushed toward the device.

17. A method for testing a microdevice array, comprising: aligning the probe array in the probe card assembly according to claim 1 with corresponding microdevices on the substrate; moving the probe card assembly to the microdevice; biasing one or more probes to allow measurement of at least one property of the at least one microdevice; monitoring a change in at least one property of the microdevice; and The connection of the micro-device is detected by the change of at least one property of the micro-device.

18. The method of claim 17, wherein the one or more probes are biased at different areas of the probe card assembly.

19. The method of claim 17, wherein the changes in at least one property of the microdevice in different areas of the probe card assembly identify connected areas and unconnected areas.

20. The method of claim 17, wherein in response to having no connection between the probe tip and the microdevice at some areas, the probe is tilted toward the unconnected areas.

21. The method of claim 17, wherein monitoring the change in at least one property of the microdevice comprises monitoring a change in capacitance or resistance.

22. The method of claim 17, further comprising: One or more force electrodes are utilized to the one or more probes to detect the connection.

23. A method for planarizing a wafer of microdevices for testing, comprising: providing at least one support for at least one probe unit according to claim 1 connected to the wafer; aligning a corresponding area of ​​the wafer that does not have a microdevice to be tested to the at least one support member; The corresponding area is pushed using the support member.

24. The method of claim 23, wherein the at least one support creates different zones, and each zone has a probe card covering the zone to test the microdevice.

25. The method of claim 23, wherein a single probe card is moved between different zones of the wafer created by the at least one support.

Images