Apparatus for transferring a semiconductor die from an arrangement of semiconductor dies to a target

Abstract

The present disclosure proposes an apparatus for transferring a semiconductor die (2) from an arrangement of semiconductor dies to a target. The apparatus according to the disclosure comprises a wafer stage (5) which is configured to receive a flexible carrier (14) on which the arrangement of semiconductor dies can be arranged, wherein the flexible carrier (14) is a sheet like element having at least two pairs of opposite edges wherein opposite edges are at least partially substantially parallel, wherein the wafer stage (5) comprising: a releasing unit (4) for releasing a semiconductor die from the arrangement of semiconductor dies, a controller for controlling the releasing unit and / or the wafer stage, a first archlike edge mount (7a) suitable for receiving first edge of flexible carrier (14) and a second archlike edge mount (7b) suitable for receiving second edge of flexible carrier (14) opposite the edge received by the first archlike edge mount (7a) at least two motors (16) having common rotation axis each coupled to the archlike edge mounts (7a, 7b) accordingly, wherein the two motors are configured for synchronously rotating each of the archlike edge mounts (7a, 7b) around a rotational axis.

Description

[0001] TITLE

[0002] APPARATUS FOR TRANSFERRING A SEMICONDUCTOR DIE FROM AN ARRANGEMENT OF SEMICONDUCTOR DIES TO A TARGET

[0003] TECHNICAL FIELD

[0004] Aspects of the present disclosure relate to an apparatus for transferring a semiconductor die from an arrangement of semiconductor dies to a target. Further aspects of the present disclosure relate to a wafer stage to be used in such apparatus.

[0005] BACKGROUND OF THE DISCLOSURE

[0006] An apparatus for transferring a semiconductor die from a diced semiconductor wafer to a target is known in the art. For example, US 2017140959 A1 discloses an apparatus that comprises a wafer stage having a wafer chuck on which a diced semiconductor wafer can be arranged, and a target stage having a target chuck on which the target can be arranged. Both the wafer stage and target stage comprise one or more motors for changing the mutual position between the diced semiconductor wafer on the wafer chuck and the target on the target chuck. The apparatus further comprises a releasing unit in the form of a needle for releasing a semiconductor die from the diced semiconductor wafer. The releasing unit, the wafer stage, and the target stage are controlled using a controller.

[0007] In the known system, a diced semiconductor wafer is brought into proximity of the target, which for example could be a printed-circuit board. When a semiconductor die on the semiconductor wafer is in alignment with an intended position on the target, the needle is brought into alignment with the semiconductor die. The needle then presses the semiconductor die away from the semiconductor wafer and onto the target.

[0008] The die transfer above is referred to as a direct die transfer. More in particular, the die is transferred from the diced semiconductor wafer onto the target without being placed or supported in between the steps of releasing the die and placing the die onto the target.

[0009] An important figure of merit for apparatuses of the type described above is the number of semiconductor dies that can be transferred per unit time. This time is often limited by the step of positioning the semiconductor wafer relative to the target. SUMMARY OF THE DISCLOSURE

[0010] An aspect of the present disclosure is related to providing an alternative apparatus for transferring a semiconductor die from an arrangement of semiconductor dies to a target that employs a different manner in which the arrangement of semiconductor dies is positioned relative to the target. According to an aspect of the present disclosure, this alternative apparatus allows faster accelerations due to reduced moment of inertia and therefore higher throughput, additionally it reduces the costs of operation due to simplified design which does not require accurate manufacturing of the element that is suitable for carrying the semiconductor wafer.

[0011] According to an aspect of the present disclosure, the apparatus for transferring a semiconductor die from an arrangement of semiconductor dies to a target is provided. It comprises a wafer stage which is configured to be coupled with a flexible carrier on which the arrangement of semiconductor dies can be arranged, a releasing unit for releasing a semiconductor die from the arrangement of semiconductor dies.

[0012] The wafer stage comprises first archlike edge mount which is suitable for receiving an edge of the flexible carrier and second archlike edge mount suitable for receiving opposite edge of the flexible carrier. The wafer stage further comprises at least two motors each coupled to the archlike edge mounts accordingly. The motors are configured for synchronously rotating each of the archlike edge mounts around a rotational axis.

[0013] The rotation of the flexible carrier allows the movement and positioning of the single die over the target and releasing it using light or needle as an engaging unit. Improvement provided by the disclosure is to obtain high acceleration values during the movement of the flexible carrier over the target with high resolutions and precision. Wafer stage with rotating flexible carrier having low moment of inertia provides much less vibrations to the apparatus during start and stop of a movement. Less inertia provides also less torsional stress to the flexible carrier.

[0014] The apparatus is preferably configured to transfer the semiconductor dies from the arrangement of semiconductor dies onto the target directly. The releasing unit can be configured for releasing a semiconductor die from the arrangement of semiconductor dies such that it falls onto the target. In this case, the releasing unit is not engaging the semiconductor die at the moment it arrives at the desired position on the target. In other embodiments, an auxiliary unit can be used to direct the released semiconductor die to the target. For example, a burst of compressed air may be used to push the released semiconductor die towards the target. In such cases, the semiconductor die can be displaced towards the target against Earth's gravitational force. In another example release mechanism using needle or laser is provided or any other that can work against gravity as the dies are given momentum. In another example air bearing surface on the release unit is provided to push out the foil locally. The subsequent friction this induces is counteracted with a small layer of air between the release unit and the foil.

[0015] The arrangement of semiconductor dies can be comprised by a diced semiconductor wafer or by a structured semiconductor wafer. A structured semiconductor wafer may comprise a plurality of semiconductor dies that are arranged in a pattern that is different from a pattern in which the dies were arranged prior to dicing the semiconductor wafer they originate from. Alternatively, a structured semiconductor wafer may comprise a plurality of semiconductor dies that originate from different semiconductor wafers. In such case, the semiconductor dies have been individually placed onto a carrier such as a film, foil, or tape.

[0016] According to an aspect of the present disclosure an apparatus for transferring a semiconductor die from an arrangement of semiconductor dies to a target, comprising a wafer stage which is configured to receive a flexible carrier on which the arrangement of semiconductor dies can be arranged, wherein the flexible carrier is a sheet like element having at least two pairs of opposite edges wherein opposite edges are at least partially substantially parallel, wherein the wafer stage comprising: a) a releasing unit for releasing a semiconductor die from the arrangement of semiconductor dies; b) a controller for controlling the releasing unit and / or the wafer stage; c) a first archlike edge mount suitable for receiving first edge of flexible carrier and d) a second archlike edge mount suitable for receiving second edge of flexible carrier opposite the edge received by the first archlike edge mount e) at least two motors having common rotation axis each coupled to the archlike edge mounts accordingly, wherein the two motors are configured for synchronously rotating each of the archlike edge mounts around a rotational axis, wherein the dimensions of arc of the archlike edge mount at least partially corresponds to the dimensions of arc of the archlike edge mount and wherein the archlike edge mounts are facing each other forming a void between them and are configured for rotating over common axis and the two motors are mounted away from the void and the releasing unit is configured for operating in the void between the archlike edge mounts and is configured to move at least along the rotation axis.

[0017] Preferably the arc of the archlike edge mount is between 120-180 degrees, more preferably 150-180 degrees.

[0018] Preferably the archlike edge mounts further comprise an edge mounts and a socket located at the beginning and at the end of the arc of the archlike mounts, configured to receive at least partially the edge mounts coupled with the two opposite flexible carrier edges.

[0019] Preferably the edge mounts have form of clamps configured to clench at least part of the flexible carrier edge.

[0020] Preferably the socket comprise means for providing a tensioning force to the flexible carrier, wherein the tensioning force is substantially perpendicular to the rotation axis.

[0021] Preferably the means for providing tensioning force are screw like elements.

[0022] Preferably at least one of the archlike elements is configured to move along the rotation axis for increasing or decreasing distance between the archlike edge mounts suitable for providing a tension force to the flexible carried along the rotation axis.

[0023] Preferably the two motors are rotating synchronously by means of mechanical coupling.

[0024] Preferably the two motors are rotating synchronously by means of servomechanical coupling comprising rotation angle sensor of each motor and a control unit for matching rotation position of each motor.

[0025] Preferably wherein archlike edge mounts are partially hollow structures providing reduce weight and reduced moment of inertia.

[0026] Preferably the releasing unit further comprises a light directing unit, a light source that is configured to emit light towards the light directing unit, and wherein the light directing unit is configured for directing light from the light source towards the flexible carrier, preferably in a substantially perpendicular manner.

[0027] Preferably the releasing unit is configured for releasing a semiconductor die from the arrangement of semiconductor dies mounted in the flexible carrier, which semiconductor die is arranged at a release position, wherein the arrangement of semiconductor dies optionally comprises a plurality of semiconductor dies arranged in a matrix of rows and columns, wherein the rows extend at least substantially in parallel to the rotational axis. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] The disclosure will now be discussed with reference to the drawings, which show in:

[0029] Figure 1 shows an example of an apparatus for placing a semiconductor die from a diced semiconductor wafer onto a target in accordance with the present disclosure;

[0030] Figure 2 shows further details of the example of the apparatus of Figure 1 ;

[0031] Figure 3 shows a further aspect of the example of the apparatus of Figure 1.

[0032] DETAILED DESCRIPTION OF THE DISCLOSURE

[0033] For a proper understanding of the disclosure, in the detailed description below corresponding elements or parts of the disclosure will be denoted with identical reference numerals as in the drawings.

[0034] Hereinafter, embodiments will be presented in which a semiconductor die from a diced semiconductor wafer is placed on a target. The present disclosure is however not limited to placing semiconductor dies from diced semiconductor wafers. In general, semiconductor dies can be placed from an arrangement of dies including but not limited to diced semiconductor wafers and structured wafers.

[0035] Figure 1 illustrates an apparatus 1 for placing a semiconductor die from a diced semiconductor wafer onto a target in accordance with an aspect of the present disclosure. Here, diced singulated semiconductor wafer is arranged on a flexible carrier 14 that is mounted on the arches of the two archlike edge mounts 7a, 7b , bending the flexible carrier 14 into an section of a cylinderlike shape. Each of the archlike edge mounts 7a, 7b is connected to motors 16 which are configured to rotate the flexible carrier 14 synchronously with the same speed and angular position around the rotational axis 15.

[0036] Preferably the motors can achieve acceleration (of the foil surface, tangential acceleration) around 300 m / s2in some examples the acceleration is over 1000 m / s2. Further preferably the motors 16 are mounted inside a sleeve 17 which is configured to cool the motors for improved performance. The cooling system can utilize thermal electrical cooling, water cooling, air cooling or any other commonly used cooling method. Synchronously for the purpose of this disclosure is defined as starting and finishing the rotation at the same time with the same acceleration and velocity in function of time. Synchronous rotation provides no torque or torsional stresses introduced to the flexible carrier 14 so that no deformation is introduced to the flexible carrier 14.

[0037] The shape and dimensions of arc of the archlike edge mount 7a at least partially corresponds to the dimensions of arc of the archlike edge mount 7b. This provides a parallellike surfaces on which the flexible carrier 14 is mounted on the archlike mounts 7a, 7b therefore the flexible carrier 14 is bend into the cylinderlike shape. The flexible carrier 14 is preferably mounted onto the arc part of the archlike mounts 7a, 7b using any suitable means preferably suction force provided by vacuum pump and delivered by channels and holes in the arc surface, screws, clamps, or any other mechanical mounting system. Mounting is possible also using adhesion glue or magnetic force. However, the flexible carrier in the preferred example rest on the arcs of the archlike mounts 7a, 7b without any mounting system or elements. In this example flexible carrier 14 is clamped by the edge mounts 8 which are mounted in sockets 9 located at the beginning and at the end of the arc of the archlike mounts 7a, 7b accordingly.

[0038] In the preferred example the archlike edge mounts 7a, 7b are mirror elements, facing each other forming a void between them and are configured for rotating over common axis 15 with the two motors 16 mounted away from the void. In the formed void the releasing unit 4 is operating. The releasing unit 4 can move in any direction but at least along the rotation axis 15. Relevant movement of the releasing unit 4 along the rotation axis 15 and rotation of the flexible carrier 14 provided by the archlike mounts 7a, 7b with synchronized motors 16 positions the releasing unit 4 over or under the single die element attached to the flexible carrier 14 selected by the control unit. This configuration provides a cylindrical coordinate system.

[0039] Flexible carrier 14 has, at least for the most part, a constant cross section along rotational axis, flexible carrier 14 can be bent into arch of different angle depending on the shape of the arctic edge mounts 7a, 7b , in particular the archlike edge mounts 7a, 7b is partially circular shape or elliptical shape and the flexible carrier 14 mounted on the archlike edge mounts 7a, 7b form a cylinderlike surface.

[0040] In the preferred example of the disclosure the arc of the archlike edge mount 7a, 7b is between 120-180 degrees more preferably 150-180 degrees. The angle of the arch bigger than 180 is not suitable for providing the releasing unit 4 with height higher than the diameter of the cylinderlike bended flexible carrier 14.

[0041] Arches having arch angel larger than 180 degrees are suitable for releasing units having high dimension smaller than the diameter of the cylinderlike bended flexible carrier 14 and configured for mounting then through the opening in at least one archlike mount 7a, 7b and / or at least one motor 16.

[0042] By mounting the flexible carrier 14 by its edges, two opposite edges resting on the arches of archlike mounts 7a, 7b in the cylinderlike manner, and the other two opposite edges clamped by the edge clamps, the rest area of flexible carrier 14 is free for processing. There is no dies supporting element provided other than tensioned flexible carrier 14. This allows releasing unit 4 to be mounted, which pushes out the wafer foil to a defined height. The apparatus and protruding element are shown in Figure 2 without the flexible carrier 14 mounted on for the purpose of achieving clarity of the figure.

[0043] As seen in Figure 3, the flexible carrier 14 further comprise edge mounts 8 which are mounted on a pair of opposite edges of the flexible carrier 14 which are not used for attaching the flexible carrier to the archlike edge mounts 7a, 7b. The archlike edge mounts 7a, 7b preferably comprise additional sockets 9 configured to receive and be coupled with the edge mounts 8. The edge mounts 8 may have the form of clamps configured to clamp or clench at least part of the opposite edges of the flexible carrier 14.

[0044] It is also beneficial that one side of the wafer stage comprising one archlike edge mount 7a or 7b is configured to be moved along the rotational axis 15 in order to simplify the removal and mounting of the flexible carrier 14 or to provide tension to the flexible carrier 14.

[0045] It should be noted that the present disclosure is not limited to the abovementioned combination of motors, clamps or archlike elements. Disclosed apparatus may comprise more or less motors, clamps or archlike elements for translating in a different direction.

[0046] Various inspection systems can be mounted to the apparatus. An inspection system can be used for inspecting semiconductor dies from diced semiconductor wafer. Such inspection may comprise determining position and orientation of semiconductor dies. This allows a final correction to be made.

[0047] Another or the same camera can also be used for checking whether a semiconductor die is damaged prior to releasing that die. If it is determined that a semiconductor die is damaged, it may be decided, by controller of apparatus 1, to skip that semiconductor die.

[0048] Another or the same camera can also be used for checking whether a semiconductor die has been released. If it is determined that this semiconductor die was not released, a new releasing attempt can be made.

[0049] In the above, the present disclosure has been described using detailed embodiments thereof. However, the present disclosure is not limited to these embodiments. Instead, various modifications are possible without departing from the scope of the present disclosure which is defined by the appended claims and their equivalents.

[0050] Particular and preferred aspects of the disclosure are set out in the accompanying independent claims. Combinations of features from the dependent and / or independent claims may be combined as appropriate and not merely as set out in the claims.

[0051] The term "comprising" does not exclude other elements or steps, the term "a" or "an" does not exclude a plurality. Reference signs in the claims shall not be construed as limiting the scope of the claims.

[0052] LIST OF REFERENCE NUMERALS USED

[0053] 1 apparatus

[0054] 2 die

[0055] 4 releasing unit

[0056] 5 wafer stage

[0057] 7a-7b archlike edge mount

[0058] 8 edge mount

[0059] 9 socket

[0060] 14 flexible carrier

[0061] 15 rotational axis

[0062] 16 motor

[0063] 17 sleeve to cool motor 16

Claims

CLAIMS1. An apparatus for transferring a semiconductor die from an arrangement of semiconductor dies to a target, comprising a wafer stage which is configured to receive a flexible carrier on which the arrangement of semiconductor dies can be arranged, wherein the flexible carrier is a sheet like element having at least two pairs of opposite edges wherein opposite edges are at least partially substantially parallel, wherein the wafer stage comprising: a) a releasing unit for releasing a semiconductor die from the arrangement of semiconductor dies; b) a controller for controlling the releasing unit and / or the wafer stage; c) a first archlike edge mount suitable for receiving first edge of flexible carrier and d) a second archlike edge mount suitable for receiving second edge of flexible carrier opposite the edge received by the first archlike edge mount; at least two motors having common rotation axis each coupled to the archlike edge mounts accordingly, wherein the two motors are configured for synchronously rotating each of the archlike edge mounts around a rotational axis, wherein the dimensions of arc of the archlike edge mount at least partially corresponds to the dimensions of arc of the archlike edge mount and wherein the archlike edge mounts are facing each other forming a void between them and are configured for rotating over common axis and the two motors are mounted away from the void and the releasing unit is configured for operating in the void between the archlike edge mounts and is configured to move at least along the rotation axis.

2. The apparatus according to claim 1, wherein the arc of the archlike edge mount (7a, 7b) is between 90-180 degrees, more preferably 110-160 degrees.

3. The apparatus according to claim 1 or 2, wherein the archlike edge mounts further comprise an edge mounts and a socket located at the beginning and at the end of the arc of the archlike mounts, configured to receive at least partially the edge mounts (8) coupled with the two opposite flexible carrier edges.

4. The apparatus according to claim 3, wherein the edge mounts have form of clamps configured to clench at least part of the flexible carrier edge.

5. The apparatus according to claim 3 or 4, wherein the socket comprise means for providing a tensioning force to the flexible carrier wherein the tensioning force is substantially perpendicular to the rotation axis.

6. The apparatus according to claim 5, wherein the means for providing tensioning force are screw like elements.

7. The apparatus according to any of the previous claims, wherein at least one of the archlike elements is configured to move along the rotation axis for increasing or decreasing distance between the archlike edge mounts suitable for providing a tension force to the flexible carrier along the rotation axis.

8. The apparatus according to any of the previous claims wherein the two motors are rotating synchronously by means of mechanical coupling.

9. The apparatus according to any of the previous claims, wherein the two motors are rotating synchronously by means of servomechanical coupling comprising rotation angle sensor of each motor and a control unit for matching rotation position of each motor.

10. The apparatus according to any of the previous claims, wherein archlike edge mounts are partially hollow structures providing reduce weight and reduced moment of inertia.

11. The apparatus according to claim 9, wherein the releasing unit further comprises a light directing unit, a light source that is configured to emit light towards the light directing unit, and wherein the light directing unit is configured for directing light from the light source towards the flexible carrier, preferably in a substantially perpendicular manner.

12. The apparatus according to any of the previous claims, wherein the releasing unit is configured for releasing a semiconductor die from the arrangement of semiconductor dies mounted in the flexible carrier, which semiconductor die is arranged at a release position, wherein the arrangement of semiconductor dies optionally comprises a plurality of semiconductor dies arranged in a matrix of rows and columns, wherein the rows extend at least substantially in parallel to the rotational axis.

13. The apparatus according to any of the previous claims, wherein the releasing unit is configured for pushing the foil radially outward to place semiconductor die on the target element.

14. The apparatus according to any of the previous claims, wherein the releasing unit further comprise an air bearing unit between the releasing unit and the flexible carries for reducing friction.

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